Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/22/12
AREA FORECAST DISCUSSION
NWS TUCSON AZ
305 PM MST FRI JUL 20 2012
.SYNOPSIS...MONSOONAL MOISTURE HAS RETURNED AND THIS WILL LEAD TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS THIS WEEKEND INTO
EARLY NEXT WEEK.
&&
.DISCUSSION...MID-AFTERNOON DOPPLER RADAR SHOWED ISOLATED SHOWERS
AND THUNDERSTORMS ACROSS THE AREA. SENT UP A BALLOON LATE THIS
MORNING TO SEE IF THERE HAVE BEEN ANY CHANGES TO THE PROFILE. IT DID
SHOW AN INCREASE IN MID-LEVEL STEERING FLOW AND THE STORMS TODAY ARE
MOVING AROUND 12-20 MPH. THIS WILL LIMIT FLASH FLOODING POTENTIAL
BUT WITH INVERTED-V PROFILE...THE THREAT OF SEEING ISOLATED SEVERE
WINDS IS THERE. SPC HAS CENTRAL PORTIONS OF THE AREA UNDER A SLIGHT
RISK. ACTIVITY OVER THE NEXT 6 HOURS...WILL BASICALLY BE ACROSS
PINAL/PIMA/SANTA CRUZ COUNTIES...WITH ISOLATED GRAHAM/COCHISE
COUNTIES. INTERESTING TO NOTE THAT LATER TONIGHT THE UOFA WRF MODELS
AND THE HRRR MODEL ARE ROTATING STORMS FROM SW NEW MEXICO/NW
CHIHUAHUA INTO THE EASTERN ZONES. WITH THE POSSIBILITY THAT THIS
MIGHT HAPPEN...HAVE KEPT POPS UP IN THE EASTERN ZONES DURING THE
OVERNIGHT PERIOD. THE NEXT SHIFT WILL MONITOR TRENDS AND MAY END UP
DOING AN UPDATE TO THE FORECAST.
APPROACHING INVERTED TROF WILL KEEP THE AREA ACTIVITY THIS WEEKEND
WITH THE THREAT OF WET MICROBURSTS EACH DAY. TEMPERATURES THIS
WEEKEND FOR THE MOST PART WILL BE AT OR SLIGHTLY BELOW NORMAL.
MODELS STILL KEEP THE AREA ACTIVE ON MONDAY AND THEN GRADUALLY BRING
DRIER AIR INTO THE AREA...THUS LIMITING DAILY THUNDERSTORMS BELOW
STANDARD MONSOON FORECAST...GENERALLY JUST ISOLATED THUNDERSTORMS.
TEMPERATURES WILL BE AROUND NORMAL NEXT WEEK.
&&
.AVIATION...ISOLD-SCT TSRA/SHRA THIS AFTERNOON BECOMING MORE
WIDESPREAD THIS EVENING THEN ISOLD -TSRA/-SHRA 06Z-12Z SATURDAY.
SCT-BKN MID LEVEL CLOUDS WITH BASES 8-10K FT EXPECTED OVER THE NEXT
24 HOURS. BRIEF WIND GUSTS APPROACHING 45 KTS WITH THE STRONGEST
TSRA. OTHERWISE...VFR CONDITIONS AND SURFACE WIND GENERALLY LESS
THAN 10 KTS THRU SATURDAY AFTERNOON OR 21/20Z. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST ARIZONA TODAY AND AGAIN TOMORROW AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE AREA FROM THE EAST BRINGING WITH IT
PLENTY OF MOISTURE. SLIGHTLY DRIER AIR WILL THEN MOVE INTO THE AREA
FOR THE START OF NEXT WEEK...BUT ENOUGH MOISTURE WILL REMAIN FOR
MORE ISOLATED MAINLY AFTERNOON AND EVENING THUNDERSTORMS.
&&
.CLIMATE...THE QUICK MOVING THUNDERSTORM THAT HIT THE TUCSON
INTERNATIONAL AIRPORT BETWEEN 145 PM AND 215 PM...DROPPED 0.34" INTO
THE RAIN GAUGE. THUS AS OF 245 PM THE MONSOON AND SUMMER RAINFALL
TOTALS ARE UP TO 4.19"...WHICH RANK AS THE 2ND WETTEST MONSOON AND
3RD WETTEST SUMMER TO DATE. THE TOTAL FOR JULY IS UP TO 3.85" WHICH
RANKS AS 2ND WETTEST TO DATE AND 19TH WETTEST FOR ENTIRE MONTH OF
JULY. LASTLY...THE 2012 TOTAL IS UP TO 4.87" WHICH RANKS AS 40TH
WETTEST TO DATE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS TUCSON AZ
250 PM MST FRI JUL 20 2012
.SYNOPSIS...MONSOONAL MOISTURE HAS RETURNED AND THIS WILL LEAD TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS THIS WEEKEND INTO
EARLY NEXT WEEK.
&&
.DISCUSSION...MID-AFTERNOON DOPPLER RADAR SHOWED ISOLATED SHOWERS
AND THUNDERSTORMS ACROSS THE AREA. SENT UP A BALLOON LATE THIS
MORNING TO SEE IF THERE HAVE BEEN ANY CHANGES TO THE PROFILE. IT DID
SHOW AN INCREASE IN MID-LEVEL STEERING FLOW AND THE STORMS TODAY ARE
MOVING AROUND 12-20 MPH. THIS WILL LIMIT FLASH FLOODING POTENTIAL
BUT WITH INVERTED-V PROFILE...THE THREAT OF SEEING ISOLATED SEVERE
WINDS IS THERE. SPC HAS CENTRAL PORTIONS OF THE AREA UNDER A SLIGHT
RISK. ACTIVITY OVER THE NEXT 6 HOURS...WILL BASICALLY BE ACROSS
PINAL/PIMA/SANTA CRUZ COUNTIES...WITH ISOLATED GRAHAM/COCHISE
COUNTIES. INTERESTING TO NOTE THAT LATER TONIGHT THE UOFA WRF MODELS
AND THE HRRR MODEL ARE ROTATING STORMS FROM SW MEXICO/NW CHIHUAHUA
INTO THE EASTERN ZONES. WITH THE POSSIBILITY THAT THIS MIGHT
HAPPEN...HAVE KEPT POPS UP IN THE EASTERN ZONES DURING THE OVERNIGHT
PERIOD. THE NEXT SHIFT WILL MONITOR TRENDS AND MAY END UP DOING AN
UPDATE TO THE FORECAST.
APPROACHING INVERTED TROF WILL KEEP THE AREA ACTIVITY THIS WEEKEND
WITH THE THREAT OF WET MICROBURSTS EACH DAY. TEMPERATURES THIS
WEEKEND FOR THE MOST PART WILL BE AT OR SLIGHTLY BELOW NORMAL.
MODELS STILL KEEP THE AREA ACTIVE ON MONDAY AND THEN GRADUALLY BRING
DRIER AIR INTO THE AREA...THUS LIMITING DAILY THUNDERSTORMS BELOW
STANDARD MONSOON FORECAST...GENERALLY JUST ISOLATED THUNDERSTORMS.
TEMPERATURES WILL BE AROUND NORMAL NEXT WEEK.
&&
.AVIATION...ISOLD-SCT TSRA/SHRA THIS AFTERNOON BECOMING MORE
WIDESPREAD THIS EVENING THEN ISOLD -TSRA/-SHRA 06Z-12Z SATURDAY.
SCT-BKN MID LEVEL CLOUDS WITH BASES 8-10K FT EXPECTED OVER THE NEXT
24 HOURS. BRIEF WIND GUSTS APPROACHING 45 KTS WITH THE STRONGEST
TSRA. OTHERWISE...VFR CONDITIONS AND SURFACE WIND GENERALLY LESS
THAN 10 KTS THRU SATURDAY AFTERNOON OR 21/20Z. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST ARIZONA TODAY AND AGAIN TOMORROW AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE AREA FROM THE EAST BRINGING WITH IT
PLENTY OF MOISTURE. SLIGHTLY DRIER AIR WILL THEN MOVE INTO THE AREA
FOR THE START OF NEXT WEEK...BUT ENOUGH MOISTURE WILL REMAIN FOR
MORE ISOLATED MAINLY AFTERNOON AND EVENING THUNDERSTORMS.
&&
.CLIMATE...THE QUICK MOVING THUNDERSTORM THAT HIT THE TUCSON
INTERNATIONAL AIRPORT BETWEEN 145 PM AND 215 PM...DROPPED 0.34" INTO
THE RAIN GAUGE. THUS AS OF 245 PM THE MONSOON AND SUMMER RAINFALL
TOTALS ARE UP TO 4.19"...WHICH RANK AS THE 2ND WETTEST MONSOON AND
3RD WETTEST SUMMER TO DATE. THE TOTAL FOR JULY IS UP TO 3.85" WHICH
RANKS AS 2ND WETTEST TO DATE AND 19TH WETTEST FOR ENTIRE MONTH OF
JULY. LASTLY...THE 2012 TOTAL IS UP TO 4.87" WHICH RANKS AS 40TH
WETTEST TO DATE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1040 AM MDT FRI JUL 20 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
TODAY: A FEW LIGHT SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUED
TO MOVE NORTH-NORTHEASTWARD ACROSS WEST-CENTRAL AND NORTHEAST UTAH
EARLY THIS MORNING. NAM AND HRRR SEEMED TO HANDLE THIS ACTIVITY
WELL AND BOTH INDICATED THE POSSIBILITY OF SOME ISOLATED CELLS
LINGERING THROUGH 15Z.
HIGH PRESSURE CENTERED OVER THE CENTRAL HIGH PLAINS WILL CONTINUE
TO CARRY MONSOON MOISTURE NORTHWARD DURING THE REMAINDER OF THE
DAY. THE DEEPEST MOISTURE WILL BE OVER EASTERN UTAH...BUT MOISTURE
LEVELS SHOULD CONTINUE TO RISE OVER WESTERN COLORADO. DAYTIME
WARMING WORKING ON MONSOON MOISTURE WILL BRING SCATTERED TO
NUMEROUS THUNDERSTORMS TO THE MOUNTAIN AREAS FROM LATE MORNING
INTO THE EVENING. AS DIURNAL CIRCULATIONS BREAK DOWN LATER IN THE
AFTERNOON...EXPECT WIDELY SCATTERED STORMS TO IMPACT THE LOWER
ELEVATIONS.
INCREASED CLOUD AND SHOWER/STORM COVERAGE WILL SHOULD BRING HIGHS
DOWN A FEW DEGREES ACROSS THE REGION.
TONIGHT THROUGH SUNDAY: EASTERN UTAH AND WESTERN COLORADO WILL
CONTINUE TO SIT ON THE WESTERN SIDE OF THE LARGE DOMINATING HIGH
PRESSURE RIDGE PARKED OVER THE CENTRAL CONUS. THIS WILL KEEP US IN
A FAVORABLE POSITION FOR THE MONSOONAL MOISTURE SURGE TO PERSIST
THROUGH THE WEEKEND. THE RIDGE DOES BECOME FLATTENED A LITTLE AS
PACIFIC ENERGY MOVES ACROSS SOUTHWEST CANADA. BUT THIS WILL HAVE
LITTLE IMPACT TO OUR SENSIBLE WEATHER. THE AREA WILL SEE A GRADUAL
INCREASE IN MOISTURE THROUGH SUNDAY. DIURNALLY FAVORED SHOWERS AND
THUNDERSTORMS WILL DEVELOP EACH DAY...WITH SOME ACTIVITY
CONTINUING OVERNIGHT. LOCALIZED HEAVY RAIN WILL BE POSSIBLE. ALSO
IF ANY WEAK BUT UNRESOLVED DISTURBANCES ROTATE ACROSS THE AREA...
SHOWERS AND THUNDERSTORMS WILL BE ENHANCED.
WITH THE INCREASED CLOUD COVER AND BETTER CHANCE OF RAIN...HIGH
TEMPERATURES WILL BE DOWN A FEW DEGREES AS COMPARED TO THE LAST FEW
DAYS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
THE BROAD AREA OF HIGH PRESSURE INDICATED TO REMAIN QUASI-
STATIONARY OVER THE CENTRAL PLAINS THROUGH NEXT WEEK. AS A
RESULT...MONSOON MOISTURE WILL CONTINUE TO MOVE OVER THE REGION
UNABATED RESULTING IN LARGELY DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS EACH DAY. TEMPERATURES WILL HOVER NEAR NORMAL FOR
THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1029 AM MDT FRI JUL 20 2012
VFR CONDITIONS WILL PREVAIL ACROSS THE REGION FOR THE REMAINDER OF
THIS MORNING. THIS AFTERNOON DAYTIME HEATING WILL BRING ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS. BY MIDAFTERNOON...SCATTERED TO
NUMEROUS THUNDERSTORM COVERAGE WILL RESULT IN FREQUENT MOUNTAIN
OBSCURATIONS AND GUSTY OUTFLOW WINDS TO 45 MPH. REGIONAL AIRPORTS
FACE THE BEST CHANCE OF THUNDERSTORMS FROM 21Z TO 03Z WITH THOSE
IN CLOSE PROXIMITY TO HIGHER TERRAIN TO THE SOUTH FAVORED. THESE
STORMS WILL BRING BRIEF MVFR CIGS AND/OR VSBY IN HEAVY RAIN.
SHOWERS AND THUNDERSTORMS WILL DECREASE...BUT NOT FULLY DIMINISH
OVERNIGHT. LITTLE CHANGE IS EXPECTED SATURDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...NL/EH
LONG TERM...NL
AVIATION...MC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
400 AM MDT FRI JUL 20 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
TODAY: A FEW LIGHT SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUED
TO MOVE NORTH-NORTHEASTWARD ACROSS WEST-CENTRAL AND NORTHEAST UTAH
EARLY THIS MORNING. NAM AND HRRR SEEMED TO HANDLE THIS ACTIVITY
WELL AND BOTH INDICATED THE POSSIBILITY OF SOME ISOLATED CELLS
LINGERING THROUGH 15Z.
HIGH PRESSURE CENTERED OVER THE CENTRAL HIGH PLAINS WILL CONTINUE
TO CARRY MONSOON MOISTURE NORTHWARD DURING THE REMAINDER OF THE
DAY. THE DEEPEST MOISTURE WILL BE OVER EASTERN UTAH...BUT MOISTURE
LEVELS SHOULD CONTINUE TO RISE OVER WESTERN COLORADO. DAYTIME
WARMING WORKING ON MONSOON MOISTURE WILL BRING SCATTERED TO
NUMEROUS THUNDERSTORMS TO THE MOUNTAIN AREAS FROM LATE MORNING
INTO THE EVENING. AS DIURNAL CIRCULATIONS BREAK DOWN LATER IN THE
AFTERNOON...EXPECT WIDELY SCATTERED STORMS TO IMPACT THE LOWER
ELEVATIONS.
INCREASED CLOUD AND SHOWER/STORM COVERAGE WILL SHOULD BRING HIGHS
DOWN A FEW DEGREES ACROSS THE REGION.
TONIGHT THROUGH SUNDAY: EASTERN UTAH AND WESTERN COLORADO WILL
CONTINUE TO SIT ON THE WESTERN SIDE OF THE LARGE DOMINATING HIGH
PRESSURE RIDGE PARKED OVER THE CENTRAL CONUS. THIS WILL KEEP US IN
A FAVORABLE POSITION FOR THE MONSOONAL MOISTURE SURGE TO PERSIST
THROUGH THE WEEKEND. THE RIDGE DOES BECOME FLATTENED A LITTLE AS
PACIFIC ENERGY MOVES ACROSS SOUTHWEST CANADA. BUT THIS WILL HAVE
LITTLE IMPACT TO OUR SENSIBLE WEATHER. THE AREA WILL SEE A GRADUAL
INCREASE IN MOISTURE THROUGH SUNDAY. DIURNALLY FAVORED SHOWERS AND
THUNDERSTORMS WILL DEVELOP EACH DAY...WITH SOME ACTIVITY
CONTINUING OVERNIGHT. LOCALIZED HEAVY RAIN WILL BE POSSIBLE. ALSO
IF ANY WEAK BUT UNRESOLVED DISTURBANCES ROTATE ACROSS THE AREA...
SHOWERS AND THUNDERSTORMS WILL BE ENHANCED.
WITH THE INCREASED CLOUD COVER AND BETTER CHANCE OF RAIN...HIGH
TEMPERATURES WILL BE DOWN A FEW DEGREES AS COMPARED TO THE LAST FEW
DAYS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
THE BROAD AREA OF HIGH PRESSURE INDICATED TO REMAIN QUASI-
STATIONARY OVER THE CENTRAL PLAINS THROUGH NEXT WEEK. AS A
RESULT...MONSOON MOISTURE WILL CONTINUE TO MOVE OVER THE REGION
UNABATED RESULTING IN LARGELY DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS EACH DAY. TEMPERATURES WILL HOVER NEAR NORMAL FOR
THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 400 AM MDT FRI JUL 20 2012
THE DAY WILL BEGIN WITH VFR CONDITIONS ACROSS THE REGION. THERE
WILL LIKELY BE A FEW LIGHT SHOWERS LINGERING OVER PORTIONS OF
NORTHEAST UTAH...THOUGH THIS ACTIVITY WILL NOT ADVERSELY IMPACT
FLIGHT CATEGORIES.
MOISTURE MOVING NORTHWARD ACROSS THE REGION COMBINED WITH DAYTIME
HEATING WILL BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
WITH FEW CELLS APPEARING OVER HIGHER TERRAIN AS EARLY AS 17Z. BY
MIDAFTERNOON...SCATTERED TO NUMEROUS THUNDERSTORM COVERAGE WILL
RESULT IN FREQUENT MOUNTAIN OBSCURATIONS AND GUSTY OUTFLOW WINDS
TO 45 MPH. REGIONAL AIRPORTS FACE THE BEST CHANCE OF THUNDERSTORMS
FROM 21Z TO 03Z WITH THOSE IN CLOSE PROXIMITY TO HIGHER TERRAIN TO
THE SOUTH FAVORED. THESE STORMS WILL BRING BRIEF MVFR CIGS AND/OR
VSBY IN HEAVY RAIN.
SHOWERS AND THUNDERSTORMS WILL DECREASE...BUT NOT FULLY DIMINISH
OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...NL/EH
LONG TERM...NL
AVIATION...NL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
957 PM EDT SAT JUL 21 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL BRING DRY AND PLEASANT WEATHER
OVERNIGHT AND SUNDAY. AS HIGH PRESSURE SHIFTS EAST OF THE NEW
ENGLAND COAST...WARMER AND MORE HUMID CONDITIONS WILL RETURN
DURING THE EARLY WEEK. THE BEST CHANCE OF SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE MONDAY AND TUESDAY...AHEAD OF AND ALONG THE
NEXT COLD FRONT. HIGH PRESSURE BRINGS A RETURN TO DRY WEATHER FOR
MID WEEK...WITH ADDITIONAL SHOWERS POSSIBLE BY THE END OF THE
WORKWEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
10 PM UPDATE...
NO MAJOR CHANGES TO ONGOING FORECAST. UPDATED TEMPS/WINDS/SKY
BASED ON CURRENT SATELLITE AND LATEST HRRR FORECAST DATA. BAND OF
CLOUDS IN THE ST LAWRENCE VALLEY EXTRAPOLATES TO THE CT VALLEY
AROUND 3-4 AM...AND THIS WAS ADJUSTED IN THE FORECAST. OBSERVED
CLOUDS WITH THIS FEATURE ARE MID LEVEL OR HIGHER...SO NO PCPN
EXPECTED WITH THEM OVERNIGHT.
WITH DEW POINTS IN THE UPPER 40S AND 50S...EXPECT MIN TEMPS IN
THIS SAME RANGE WITH GOOD RADIATIONAL COOLING. PATCHY
FOG...LOCALLY DENSE...IS AGAIN EXPECTED ESPECIALLY IN THE INTERIOR
VALLEYS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...
HIGH PRESSURE CONTINUES TO SLIDE OFFSHORE FURTHER LOCKING OUR AREA
INTO A SOUTHWEST FLOW AND A GRADUAL INCREASE IN MOISTURE INCLUDING
SURFACE DEW POINTS. MODELS SHOW A SHORT WAVE CROSSING THROUGH THE AREA AS
WELL. SOME INCREASE IN CLOUDS IS EXPECTED...LARGELY VIA AN INCREASE
OF DIURNAL CUMULUS. MAY SEE SOME ISOLATED SHOWERS...MAINLY IN THE
FAR INTERIOR WHERE A SLIGHT CHANCE POP IS IN PLACE...BUT MODEL SOUNDINGS
DO INDICATE A WEAK MID LEVEL CAP AND INSTABILITY IS QUITE MARGINAL.
850 MB TEMPS AROUND 14-15C SUGGESTS THAT TEMPS WILL MAX OUT IN THE
80S MOST PLACES.
SUNDAY NIGHT...
MODELS SHOW FAIRLY MOIST AIRMASS IN PLACE WITH PWATS APPROACHING 1.5
INCHES. MODELS ALSO SHOW ANOTHER SHORT WAVE POTENTIALLY MOVING
THROUGH THE AREA. AS WITH THE PREVIOUS RUNS...THE NAM AND TO A MUCH
LESSER EXTENT THE GFS TRY TO BRING SOME WEAK OVERNIGHT CONVECTION
THROUGH THE AREA. OBVIOUSLY NO DIURNAL HEATING TO ASSIST IN
FORMATION OF CONVECTION...BUT LI/S AT OR BELOW ZERO...AND MID
LEVEL CAP APPEARS TO BE GONE. LACK OF STRONG LIFT WITH THE
EXCEPTION OF THE GFS LATE. AT THIS TIME WILL GO WITH A SLIGHT TO
LOW CHANCE POP FOR SHOWERS OR THUNDERSTORMS ACROSS THE AREA.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGHLIGHTS...
* HEAT AND HUMIDITY RETURN MONDAY AND TUESDAY
* COLD FRONT WITH SHOWERS AND THUNDERSTORMS EXPECTED MONDAY AND
TUESDAY
* HIGH PRESSURE/DRY WEATHER RETURNS MID WEEK
OVERVIEW AND MODEL PREFERENCES...
21/12Z GUIDANCE CONTINUES TO SHOW GOOD SYNOPTIC SCALE AGREEMENT
THROUGH MOST OF NEXT WEEK. THIS PERIOD IS MARKED BY A TRANSITION
FROM ZONAL FLOW ALOFT TO A MORE MERIDIONAL TROUGH/RIDGE PATTERN...
WHICH WILL AFFECT DAY TO DAY SENSIBLE WEATHER DETAILS. CONTINUE
TO LIKE PREVIOUS SHIFTS THINKING WITH GFS/NAM BLEND AS BASELINE
THROUGH THE MID TERM...WITH A GFS/ECMWF BLEND IN THE LONGER TERM.
THE TWO POINTS WHERE MODEL DISAGREEMENT MAY MAKE A BIGGER MARK ON
IS WITH THE ARRIVAL OF A STRONG SHORTWAVE AND ASSOCIATED LOW
PRESSURE/FRONTAL SYSTEM FRIDAY INTO EARLY NEXT WEEKEND. THERE ARE
STILL SOME TIMING DIFFERENCES TO BE RESOLVED...ALTHOUGH A 21/12Z
GFS/ECMWF BLEND STILL SUGGESTS UNSETTLED CONDITIONS.
DETAILS...
MONDAY AND TUESDAY...
IT STILL APPEARS SOUTHERN NEW ENGLAND WILL HAVE TO CONTEND WITH
BOTH A PRE-FRONTAL TROUGH AS WELL AS A COLD FRONT EARLY NEXT WEEK.
STILL THINKING THE COLD FRONT WILL NOT CROSS OUR REGION UNTIL
TUESDAY. CONVECTIVE INDICES STILL LOOK FAVORABLE FOR
THUNDERSTORMS...WITH THE GREATEST POTENTIAL TUESDAY. THE BIG
LIMITATION FOR STRONG TO SEVERE THUNDERSTORMS AT THIS POINT
CONTINUES TO BE WIND SHEAR WHICH IS MORE ON THE WEAK SIDE. WILL
NEED TO MONITOR THIS SITUATION OVER THE NEXT FEW DAYS.
SOUTH TO SOUTHWEST FLOW WILL BRING A RETURN TO HEAT AND
UNCOMFORTABLE HUMIDITY DURING THIS PERIOD AS WELL.
WEDNESDAY AND THURSDAY...
A MID-LEVEL TROUGH IS EXPECTED TO MOVE OVER NORTHERN NEW ENGLAND
AND THE MARITIMES DURING THIS TIMEFRAME. THIS SHOULD DIRECT A WEAK
SURFACE HIGH PRESSURE TO NUDGE SOUTH ACROSS NEW ENGLAND.
TEMPERATURES SHOULD BE NEAR NORMAL WITH MUCH MORE COMFORTABLE
HUMIDITY.
FRIDAY AND SATURDAY...
THERE ARE STILL A LOT OF DETAILS TO BE WORKED OUT FOR THIS PORTION
OF THE FORECAST. BOTH THE 21/12Z GFS AND ECMWF DEPICT UNSETTLED
WEATHER SOMETIME DURING THIS PERIOD. MAINTAINED A CHANCE OF
SHOWERS FOR NOW WITH SEASONABLE TEMPERATURES.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
TONIGHT THROUGH SUNDAY...HIGH CONFIDENCE.
VFR...BUT WITH AREAS OF FOG LATE TONIGHT ACROSS THE CT RIVER
VALLEY AND IN TYPICAL FOG SPOTS SUCH AS TAN AND OWD AND BED. LIGHT
FLOW OVERNIGHT AS HIGH PRESSURE CROSSES THROUGH THE AREA FROM THE
NORTH...THEN WINDS BECOMING SW SUNDAY AS THIS HIGH PRESSURE MOVES
OFFSHORE. POTENTIAL FOR SEA-BREEZE FORMATION AGAIN SUNDAY.
KBOS TAF...HIGH CONFIDENCE VFR THRU SUNDAY. LOW RISK OF A SEA-BREEZE
DEVELOPING SUNDAY AFTERNOON.
KBDL TAF...HIGH CONFIDENCE IN TAF...EXCEPT MODERATE CONFIDENCE OF
MVFR FOG TOWARDS AND AROUND DAYBREAK SUN.
SUNDAY NIGHT...PRIMARILY VFR...BUT RISK OF MVFR CIGS/VSBYS IN
ISOLATED SHOWERS AND THUNDERSTORMS AND PATCHY FOG.
OUTLOOK...MONDAY THROUGH THURSDAY...
MONDAY AND TUESDAY...MODERATE TO HIGH CONFIDENCE.
MAINLY VFR. BRIEF MVFR CONDITIONS ARE LIKELY WITH AFTN SCT
SHRA/TSRA BOTH DAYS.
WEDNESDAY AND THURSDAY...HIGH CONFIDENCE.
VFR.
&&
.MARINE...
MODERATE TO HIGH CONFIDENCE
TONIGHT...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FOR THE OUTER
WATERS SOUTH OF RI AND MARTHAS VINEYARD AND NANTUCKET. SOUTHERLY
SWELL WILL RESULT IN 3 TO 5 FT SEAS ACROSS THE SOUTHERN
WATERS...DIMINISHING AFTER MIDNIGHT. OTHERWISE...WINDS AND SEAS
SHOULD REMAIN BELOW SCA THRESHOLDS ACROSS THE REST OF THE WATERS.
SUN AND SUN NIGHT...WINDS AND SEAS REMAIN BELOW SCA THRESHOLDS
THROUGH THE PERIOD.
OUTLOOK...MONDAY THROUGH THURSDAY...
MONDAY THROUGH TUESDAY...MODERATE CONFIDENCE.
A COLD FRONT WILL BE SLOWLY APPROACHING THE WATERS THROUGH THE
PERIOD WITH MOSTLY SW FLOW. WIND GUSTS COULD TOUCH 25 KT POSSIBLY
DURING EACH AFTERNOON...BUT SHOULD MOSTLY REMAIN AT OR BELOW
20 KT. A BUILDING SWELL OFFSHORE COULD GET CLOSE TO 5 FT ACROSS
THE OUTER SOUTH COASTAL WATERS. A MARGINAL SMALL CRAFT ADVISORY
MAY BE NEEDED. OTHERWISE...SHOWERS AND THUNDERSTORMS WITH
LOCALLY GUSTY WINDS AND ROUGH SEAS ARE POSSIBLE EACH AFTERNOON.
WEDNESDAY AND THURSDAY...HIGH CONFIDENCE.
TRANQUIL WEATHER WITH SEAS 4 FT OR LESS AND WIND GUSTS LESS THAN
20 KT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT SUNDAY
FOR ANZ255-256.
&&
$$
SYNOPSIS...BELK/NMB
NEAR TERM...WTB
SHORT TERM...NMB
LONG TERM...BELK
AVIATION...BELK/NMB
MARINE...BELK/NMB
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
221 PM EDT FRI JUL 20 2012
.PREV DISCUSSION... /ISSUED 1140 AM EDT FRI JUL 20 2012/
UPDATE...
HAVE MADE SEVERAL MINOR TWEAKS TO GRIDS THIS MORNING...MOSTLY TO
ACCOUNT FOR HOURLY TRENDS WITH TEMPS DEWPOINTS AND POPS. SPC STILL
HAS MOST OF THE AREA IN A SLIGHT RISK FOR DAY1...AND POPS ACROSS
NORTH AND CENTRAL GEORGIA REMAIN VERY HIGH THIS AFTERNOON TO
ACCOUNT FOR CONVECTIVE DEVELOPMENT. THE CONCERN IS THAT...WITH THE
EXCEPTION OF THE MOST RECENT HRRR RUNS...NONE OF THE HIRES MODELS
HAD THE MCS REMNANTS LASTING SO LONG THIS MORNING. CONDITIONS ARE
PRETTY STABLE ACROSS NORTH GEORGIA RIGHT NOW WITH CAPES BELOW 500
IN THE RAIN-COOLED AIRMASS. HOWEVER...BEHIND THE CIRRUS SHIELD...
TEMPS ARE ALREADY STARTING TO INCREASE AND AT AFD TIME AM STARTING
TO SEE CONVECTION FIRE NEAR CHA. THINK THAT IN THE END THE
INSTABILITY WILL CATCH UP. 12Z KFFC MODIFIED SOUNDING WITH LOWER
70S DEWPOINTS AND A HIGH IN THE UPPER 80S GIVES OVER 3000 J/KG
SBCAPE SO AT THIS POINT STILL EXPECT NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP WITH SOME POSSIBLY SEVERE. POPS MAY
ACTUALLY NEED TO BE INCREASED INTO THE AFTERNOON ONCE WE GET A
HANDLE ON LOCATION AND MOVEMENT.
TDP
PREV DISCUSSION... /ISSUED 741 AM EDT FRI JUL 20 2012/
SHORT TERM /TODAY THROUGH SATURDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
INITIAL CONCERN IS THE CONVECTIVE COMPLEX (MCS) SPREADING SOUTHWARD
FROM TN THIS MORNING. REGIONAL RADARS...CLOUD TOP TEMPERATURES NOTED
ON SATELLITE AND LIGHTNING DATA ALL SUGGEST THE STRONGER STORMS WILL
PUSH INTO NORTH AL... WITH A WEAKENING TREND NOTED FOR CONVECTION
MOVING INTO NORTH GA. THEREFORE...EXPECT MAINLY SHOWERS TO PUSH
ACROSS NORTH GA THIS MORNING...TO INCLUDE METRO ATLANTA...BEFORE
DISSIPATING. HOWEVER...CANNOT RULE OUT A THUNDERSTORM OR TWO WITH
THIS ACTIVITY...SO WILL MENTION A SLIGHT CHANCE OF THUNDER THROUGH
THE MORNING HOURS. THE GREATER THUNDERSTORM THREAT WILL OCCUR DURING
AFTERNOON HEATING AS AN ACTIVE UPPER TROUGH INTERACTS WITH A MOIST
(NEAR 2 INCH PW`S) AND UNSTABLE AIR MASS (1500-2500 J/KG CAPE) TO
PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND EVENING. REMNANT OUTFLOW BOUNDARIES FROM THIS
MORNING`S MCS SHOULD HELP PROVIDE A FOCUS FOR STORM DEVELOPMENT...
AND THIS SHOULD OCCUR MAINLY OVER NORTH GA WHERE BOUNDARIES SHOULD
BE LINGERING. A SLIGHT INCREASE IN VERTICAL WIND SHEAR FROM A
STRENGTHENING SW MID LEVEL FLOW AHEAD OF A COLD FRONT PUSHING INTO
TN TODAY COULD AID IN STRONG TO SEVERE STORM DEVELOPMENT...
ESPECIALLY IF ENHANCED BY WEAK DISTURBANCES TRAVERSING THE UPPER
TROUGH TODAY. SPC HAS PLACED NORTH GA IN A SLIGHT RISK TODAY...
MAINLY NORTH OF A HAMILTON TO MONTICELLO TO WASHINGTON LINE. THE
PRIMARY THREAT WILL BE DAMAGING WIND GUSTS... BUT ALSO EXPECT
FREQUENT LIGHTNING...HEAVY RAIN AND SMALL HAIL WITH THE STRONGER
STORMS. ANY SLOW MOVING STORMS WILL PRODUCE LOCALLY HEAVY RAIN...
AND COULD RESULT IN BRIEF LOCALIZED FLASH FLOODING. MODELS AGREE ON
STALLING THE COLD FRONT OVER TN TONIGHT... THEN SAGGING THE FRONT
INTO NORTH GA ON SATURDAY WHERE IT LIKELY LINGERS BEFORE PUSHING
BACK NORTH ON SUNDAY. WILL CONTINUE TO SHOW A SLIGHT CHANCE OF
THUNDER OVERNIGHT... WITH LIKELY POPS WARRANTED AGAIN ON SATURDAY AS
THE ACTIVE UPPER TROUGH INTERACTS WITH THE FRONTAL BOUNDARY.
INCREASING CLOUDS AND CONVECTIVE ACTIVITY SHOULD HOLD DAYTIME HIGHS
DOWN INTO THE 80S FOR MOST AREAS TODAY AND AGAIN ON SATURDAY. HAVE
LEANED TOWARD A MAV AND MET BLEND THROUGH THE SHORT TERM AS MAV
LOOKED A BIT WARM AND MET COOL FOR HIGHS. THE LOWS WERE VERY CLOSE
AND LOOKED REASONABLE.
39
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
FRONTAL BOUNDARY WHICH SAGS OVER GA SAT WILL BEGIN TO PUSH BACK
NORTHWARD SAT NIGHT AS BERMUDA LIKE RIDGE BUILDS OFF THE GA/CAROLINA
COAST. THE BOUNDARY KEEPS A DECENT AMOUNT OF MOISTURE AND A FOCUSING
MECHANISM OVER THE AREA THROUGH MONDAY AFTERNOON BEFORE DIMINISHING
UNDER THE BUILDING RIDGE. SHOULD CONTINUE TO SEE A MOSTLY DIURNAL
CONVECTIVE TREND IN THE EXTENDED AS MOISTURE FROM THE GULF ROTATES
UP INTO THE AREA UNDER THE SURFACE RIDGE THROUGH DAY 7. EVEN WITH
THE HIGH IN PLACE...PLENTY OF LOW LEVEL MOISTURE WILL SUPPORT
DIURNAL CONVECTION EACH DAY. FORECAST PRECIPITABLE WATER VALUES
STILL SHOWING NEAR 2.0 INCH VALUES THROUGH THE MIDDLE OF NEXT
WEEK...AND WITH K-INDEX VALUES IN THE MID TO UPPER 30S...HEAVY RAIN
STILL REMAINS A THREAT. WIDESPREAD 1-1.25 INCHES ARE EXPECTED
THROUGH SUNDAY AFTERNOON...WITH LOCALLY HEAVIER AMOUNTS ASSOCIATED
WITH AREAS OF MODERATE TO STRONG CONVECTION. BY WEDNESDAY...LOW
PRESSURE DEEPENING OVER THE CANADIAN MARITIMES WILL DRAG ANOTHER
FRONTAL BOUNDARY THROUGH THE MID ATLANTIC STATES...WITH TROUGH
EXTENDING INTO NORTH GEORGIA. THE MODELS DO DIFFER A BIT ON JUST HOW
FAR SOUTH THIS FRONTAL BOUNDARY MOVES SO WILL CONTINUE WITH
DIURNALLY DRIVEN CHANCE POPS THROUGH DAY 7.
AS FOR TEMPERATURES...THINGS SHOULD BE A BIT COOLER THIS WEEKEND
WITH HI TEMPS IN THE 80S TO LOW 90S DUE TO THE FRONTAL BOUNDARY AND
RAIN. TEMPS WILL BEGIN TO REBOUND MONDAY THROUGH WEDNESDAY WITH
TEMPS BACK INTO THE MID 90S BY WED/THU.
01
&&
.AVIATION...
18Z UPDATE...
EXPECT CONVECTION TO DEVELOP LATER THIS AFTERNOON AND EVENING...
AND HAVE KEPT TREND WITH TEMPO IN THE TAFS. ONCE THE CONVECTION
CLEARS...SHOULD SEE ANOTHER ROUND OF MVFR VSBY AND IFR CIGS
SATURDAY MORNING MUCH LIKE THIS MORNING WAS. SOME UNCERTAINTY AS
TO WHEN AND HOW FAST THE CIGS WILL LIFT. ANOTHER ROUND OF
CONVECTION EXPECTED FOR SATURDAY AFTERNOON. SOUTHWEST WINDS
GENERALLY 5-10KT THROUGH THE PERIOD EXCEPT IN THUNDERSTORMS.
//ATL CONFIDENCE...18Z UPDATE...
HIGH ON CONVECTION TODAY AND SATURDAY AFTERNOON...MEDIUM ON
IMPACTS TO ATL.
HIGH ON DEVELOPMENT OF IFR CIGS...MEDIUM ON TIMING OF ONSET AND
LIFTING.
HIGH ON WINDS AND VSBY.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 72 84 70 / 70 60 60 40
ATLANTA 88 72 84 70 / 90 60 60 40
BLAIRSVILLE 84 69 82 66 / 70 60 60 40
CARTERSVILLE 89 71 85 70 / 80 60 60 40
COLUMBUS 89 73 88 72 / 70 50 60 30
GAINESVILLE 87 72 85 70 / 90 60 60 40
MACON 90 73 89 71 / 70 50 60 30
ROME 89 72 89 72 / 100 60 50 30
PEACHTREE CITY 88 71 85 70 / 70 60 60 40
VIDALIA 90 73 90 74 / 70 40 60 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1140 AM EDT FRI JUL 20 2012
.UPDATE...
HAVE MADE SEVERAL MINOR TWEAKS TO GRIDS THIS MORNING...MOSTLY TO
ACCOUNT FOR HOURLY TRENDS WITH TEMPS DEWPOINTS AND POPS. SPC STILL
HAS MOST OF THE AREA IN A SLIGHT RISK FOR DAY1...AND POPS ACROSS
NORTH AND CENTRAL GEORGIA REMAIN VERY HIGH THIS AFTERNOON TO
ACCOUNT FOR CONVECTIVE DEVELOPMENT. THE CONCERN IS THAT...WITH THE
EXCEPTION OF THE MOST RECENT HRRR RUNS...NONE OF THE HIRES MODELS
HAD THE MCS REMNANTS LASTING SO LONG THIS MORNING. CONDITIONS ARE
PRETTY STABLE ACROSS NORTH GEORGIA RIGHT NOW WITH CAPES BELOW 500
IN THE RAIN-COOLED AIRMASS. HOWEVER...BEHIND THE CIRRUS SHIELD...
TEMPS ARE ALREADY STARTING TO INCREASE AND AT AFD TIME AM STARTING
TO SEE CONVECTION FIRE NEAR CHA. THINK THAT IN THE END THE
INSTABILITY WILL CATCH UP. 12Z KFFC MODIFIED SOUNDING WITH LOWER
70S DEWPOINTS AND A HIGH IN THE UPPER 80S GIVES OVER 3000 J/KG
SBCAPE SO AT THIS POINT STILL EXPECT NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP WITH SOME POSSIBLY SEVERE. POPS MAY
ACTUALLY NEED TO BE INCREASED INTO THE AFTERNOON ONCE WE GET A
HANDLE ON LOCATION AND MOVEMENT.
TDP
&&
.PREV DISCUSSION... /ISSUED 741 AM EDT FRI JUL 20 2012/
SHORT TERM /TODAY THROUGH SATURDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
INITIAL CONCERN IS THE CONVECTIVE COMPLEX (MCS) SPREADING SOUTHWARD
FROM TN THIS MORNING. REGIONAL RADARS...CLOUD TOP TEMPERATURES NOTED
ON SATELLITE AND LIGHTNING DATA ALL SUGGEST THE STRONGER STORMS WILL
PUSH INTO NORTH AL... WITH A WEAKENING TREND NOTED FOR CONVECTION
MOVING INTO NORTH GA. THEREFORE...EXPECT MAINLY SHOWERS TO PUSH
ACROSS NORTH GA THIS MORNING...TO INCLUDE METRO ATLANTA...BEFORE
DISSIPATING. HOWEVER...CANNOT RULE OUT A THUNDERSTORM OR TWO WITH
THIS ACTIVITY...SO WILL MENTION A SLIGHT CHANCE OF THUNDER THROUGH
THE MORNING HOURS. THE GREATER THUNDERSTORM THREAT WILL OCCUR DURING
AFTERNOON HEATING AS AN ACTIVE UPPER TROUGH INTERACTS WITH A MOIST
(NEAR 2 INCH PW`S) AND UNSTABLE AIR MASS (1500-2500 J/KG CAPE) TO
PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND EVENING. REMNANT OUTFLOW BOUNDARIES FROM THIS
MORNING`S MCS SHOULD HELP PROVIDE A FOCUS FOR STORM DEVELOPMENT...
AND THIS SHOULD OCCUR MAINLY OVER NORTH GA WHERE BOUNDARIES SHOULD
BE LINGERING. A SLIGHT INCREASE IN VERTICAL WIND SHEAR FROM A
STRENGTHENING SW MID LEVEL FLOW AHEAD OF A COLD FRONT PUSHING INTO
TN TODAY COULD AID IN STRONG TO SEVERE STORM DEVELOPMENT...
ESPECIALLY IF ENHANCED BY WEAK DISTURBANCES TRAVERSING THE UPPER
TROUGH TODAY. SPC HAS PLACED NORTH GA IN A SLIGHT RISK TODAY...
MAINLY NORTH OF A HAMILTON TO MONTICELLO TO WASHINGTON LINE. THE
PRIMARY THREAT WILL BE DAMAGING WIND GUSTS... BUT ALSO EXPECT
FREQUENT LIGHTNING...HEAVY RAIN AND SMALL HAIL WITH THE STRONGER
STORMS. ANY SLOW MOVING STORMS WILL PRODUCE LOCALLY HEAVY RAIN...
AND COULD RESULT IN BRIEF LOCALIZED FLASH FLOODING. MODELS AGREE ON
STALLING THE COLD FRONT OVER TN TONIGHT... THEN SAGGING THE FRONT
INTO NORTH GA ON SATURDAY WHERE IT LIKELY LINGERS BEFORE PUSHING
BACK NORTH ON SUNDAY. WILL CONTINUE TO SHOW A SLIGHT CHANCE OF
THUNDER OVERNIGHT... WITH LIKELY POPS WARRANTED AGAIN ON SATURDAY AS
THE ACTIVE UPPER TROUGH INTERACTS WITH THE FRONTAL BOUNDARY.
INCREASING CLOUDS AND CONVECTIVE ACTIVITY SHOULD HOLD DAYTIME HIGHS
DOWN INTO THE 80S FOR MOST AREAS TODAY AND AGAIN ON SATURDAY. HAVE
LEANED TOWARD A MAV AND MET BLEND THROUGH THE SHORT TERM AS MAV
LOOKED A BIT WARM AND MET COOL FOR HIGHS. THE LOWS WERE VERY CLOSE
AND LOOKED REASONABLE.
39
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
FRONTAL BOUNDARY WHICH SAGS OVER GA SAT WILL BEGIN TO PUSH BACK
NORTHWARD SAT NIGHT AS BERMUDA LIKE RIDGE BUILDS OFF THE GA/CAROLINA
COAST. THE BOUNDARY KEEPS A DECENT AMOUNT OF MOISTURE AND A FOCUSING
MECHANISM OVER THE AREA THROUGH MONDAY AFTERNOON BEFORE DIMINISHING
UNDER THE BUILDING RIDGE. SHOULD CONTINUE TO SEE A MOSTLY DIURNAL
CONVECTIVE TREND IN THE EXTENDED AS MOISTURE FROM THE GULF ROTATES
UP INTO THE AREA UNDER THE SURFACE RIDGE THROUGH DAY 7. EVEN WITH
THE HIGH IN PLACE...PLENTY OF LOW LEVEL MOISTURE WILL SUPPORT
DIURNAL CONVECTION EACH DAY. FORECAST PRECIPITABLE WATER VALUES
STILL SHOWING NEAR 2.0 INCH VALUES THROUGH THE MIDDLE OF NEXT
WEEK...AND WITH K-INDEX VALUES IN THE MID TO UPPER 30S...HEAVY RAIN
STILL REMAINS A THREAT. WIDESPREAD 1-1.25 INCHES ARE EXPECTED
THROUGH SUNDAY AFTERNOON...WITH LOCALLY HEAVIER AMOUNTS ASSOCIATED
WITH AREAS OF MODERATE TO STRONG CONVECTION. BY WEDNESDAY...LOW
PRESSURE DEEPENING OVER THE CANADIAN MARITIMES WILL DRAG ANOTHER
FRONTAL BOUNDARY THROUGH THE MID ATLANTIC STATES...WITH TROUGH
EXTENDING INTO NORTH GEORGIA. THE MODELS DO DIFFER A BIT ON JUST HOW
FAR SOUTH THIS FRONTAL BOUNDARY MOVES SO WILL CONTINUE WITH
DIURNALLY DRIVEN CHANCE POPS THROUGH DAY 7.
AS FOR TEMPERATURES...THINGS SHOULD BE A BIT COOLER THIS WEEKEND
WITH HI TEMPS IN THE 80S TO LOW 90S DUE TO THE FRONTAL BOUNDARY AND
RAIN. TEMPS WILL BEGIN TO REBOUND MONDAY THROUGH WEDNESDAY WITH
TEMPS BACK INTO THE MID 90S BY WED/THU.
01
AVIATION...
12Z UPDATE...
IFR CIGS WILL PERSIST UNTIL AROUND 13-14Z...THEN A LARGE AREA OF
CONVECTION OVER NW GA SPREADS IN OVER THE ATLANTA AREA TAF SITES...
RESULTING IN TEMPO -SHRA/-TSRA AROUND 13-16Z BEFORE THIS CONVECTION
GRADUALLY DISSIPATES THROUGH 17Z. THE AIR MASS WILL TAKE SOME TIME
TO DESTABILIZE AGAIN... BUT DO EXPECT OUTFLOWS FROM MORNING
CONVECTION TO HELP SPARK ADDITIONAL TSRA DEVELOPMENT AROUND 22-02Z
TODAY. MODELS AGREE ON IFR/MVFR CIGS DEVELOPING EARLY SAT MORNING AT
MOST TAF SITES...SO WILL CONTINUE TO SHOW MVFR CIGS BY 09Z SAT AT
ATL. EXPECT A WSW WIND AT 8-10KTS TO PREVAIL TODAY...THEN BACK MORE
SOUTHERLY LATER THIS EVENING AT 4-6KTS...BUT SHOULD STAY JUST WEST
OF SOUTH OVERNIGHT. IFR/MVFR CIGS SHOULD SCT BY 15Z SAT.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF -TSRA THIS MORNING...THEN
REDEVELOPMENT LATER TODAY. MEDIUM TO HIGH CONFIDENCE ALL OTHER
ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 72 84 70 / 70 60 60 40
ATLANTA 88 72 84 70 / 90 60 60 40
BLAIRSVILLE 84 69 82 66 / 70 60 60 40
CARTERSVILLE 89 71 85 70 / 80 60 60 40
COLUMBUS 89 73 88 72 / 70 50 60 30
GAINESVILLE 87 72 85 70 / 90 60 60 40
MACON 90 73 89 71 / 70 50 60 30
ROME 89 72 89 72 / 100 60 50 30
PEACHTREE CITY 88 71 85 70 / 70 60 60 40
VIDALIA 90 73 90 74 / 70 40 60 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1233 PM EDT FRI JUL 20 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 356 AM EDT FRI JUL 20 2012
AS A COLD FRONT AND WEAK SURFACE LOW DEPART THE AREA TODAY...A
WEAK SHORTWAVE WILL TRAVERSE THE REGION. THIS WILL HAVE A SMALL
CHANCE OF SPARKING AN ADDITIONAL SHOWER OR TWO THIS MORNING BEFORE
DRY WEATHER RETURNS TO THE FORECAST THROUGH THE WEEKEND.
ADDITIONALLY...SKIES WILL BE MOSTLY CLOUDY THROUGH THE FIRST HALF
OF THE DAY AS STRATOCUMULUS BUILDS INTO THE AREA IN THE CYCLONIC
FLOW. THIS WILL ALSO HELP KEEP TEMPERATURES DOWN TODAY...WITH SOME
AREAS STRUGGLING TO EVEN REACH THE 80 DEGREE MARK...A MAJOR SHIFT
FROM RECENT RECORD BREAKING HEAT. UNFORTUNATELY...THIS RESPITE
WILL BE SHORT LIVED...AS A RAPID WARMING TREND WILL FOLLOW FOR THE
WEEKEND...WITH TEMPERATURES BACK WELL INTO THE MID 90S BY SUNDAY
AS RIDGING ONCE AGAIN ASSERTS DOMINANCE ACROSS THE AREA. NORTHWEST
FLOW ALOFT NEXT WEEK SUGGESTS ONE OR MORE CHANCES FOR
THUNDERSTORMS...BUT PROBABILITIES REMAIN LOW AND UNCERTAIN AT THE
MOMENT.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1039 AM EDT FRI JUL 20 2012
ISOLATED SHOWERS AND SPRINKLES ARE TAKING THEIR TIME ABOUT GOING
AWAY. RUC ISNT IN ANY RUSH TO GET RID OF THEM. WILL UPDATE TO KEEP
SOME PRECIP THROUGH MOST OF AFTERNOON. CURRENT POPS STILL LOOK
GOOD...BUT WILL MENTION ISOLATED SPRINKLES WEST.
TAKING TEMPS DOWN A CAT IN THE EAST AND CENTRAL WITH PRECIP AND
CLOUDS HANGING ON LONGEST THERE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 356 AM EDT FRI JUL 20 2012
WITH SURFACE HIGH PRESSURE THE DOMINANT FEATURE THROUGHOUT THE
SHORT TERM...TEMPERATURES ARE THE ONLY SIGNIFICANT FORECAST ISSUE.
MODEL 850 TEMPS WARM SIGNIFICANTLY AND QUICKLY THROUGH THE SHORT
TERM...AND ARE BACK INTO THE LOW 20C RANGE BY SUNDAY.
LATELY...THIS HAS TRANSLATED EASILY INTO THE MID 90S...AND WHILE
RECENT RAINFALL HAS MADE A SMALL DENT INTO EXTREME DROUGHT...IT
WILL TAKE MUCH MORE THAN WHAT HAS ALREADY OCCURRED TO MITIGATE
IMPACT OF DROUGHT ON TEMPERATURES. EXPECT WE WILL BEGIN TO EASILY
OUTPACE MOS ONCE AGAIN. GENERALLY RAISED CONSENSUS AT LEAST A
COUPLE OF DEGREES ON MAXES...WITH CORRESPONDING BUT SLIGHTLY
SMALLER HIKES DURING THE OVERNIGHTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 255 AM EDT FRI JUL 20 2012
LONG RANGE MODELS AND ENSEMBLES SUGGEST UPPER RIDGE ACROSS THE
PLAINS EARLY NEXT WEEK WILL SETTLE SOUTHEAST ACROSS THE SOUTHERN
STATES MIDWEEK WITH CENTRAL INDIANA ON THE SOUTHERN FRINGES OF THE
WESTERLIES. MODELS ALSO HAVE QPF THROUGH MUCH OF THE EXTENDED.
UPPER THICKNESS PATTERN IS CONDUCIVE TO PERIODIC NORTHWEST TO
SOUTHEAST MOVING THUNDERSTORM COMPLEXES ACROSS THE LOWER GREAT LAKES
AND OHIO VALLEY...SO WILL LEAVE AT LEAST SMALL CHANCE POPS
THROUGHOUT THE EXTENDED. KEPT AFTERNOON TEMPERATURES A FEW DEGREES
ABOVE MOS AND THE CENTRAL REGION INITIALIZATION AS WE STILL HAVE A
WAY TO GO BEFORE THE DROUGHT LOSES ITS IMPACT.
&&
.AVIATION /DISCUSSION FOR THE 201800Z TAFS/...
ISSUED AT 1233 PM EDT FRI JUL 20 2012
WEAK UPPER DISTURBANCE DROPPING SOUTH THROUGH THE AREA MAY BRING A
FEW SCATTERED LIGHT SHOWERS TO THE KIND/KBMG VICINITY UNTIL ABOUT
201900Z.
OTHERWISE...DRIER AIR WORKING IN AT THE LOWER LEVELS COMBINED WITH
WEAK BOUNDARY LAYER HEATING SHOULD ALLOW FOR ANY LINGERING IFR
CEILINGS TO LIFT INTO AN MVFR DECK 015-020 BY OR SHORTLY AFTER
ISSUANCE TIME. CEILINGS SHOULD CONTINUE TO RISE THROUGHOUT THE
AFTERNOON...REACHING INTO THE VFR CATEGORY BY MID TO LATE
AFTERNOON...AND EVENTUALLY SCATTERING OUT FROM NORTH TO SOUTH DURING
THE EVENING.
SURFACE WINDS MAY OCCASIONALLY APPROACH 15 KTS FROM 010-030 HEADINGS
THROUGHOUT THE AFTERNOON AND EARLY EVENING HOURS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...JK
SHORT TERM...NIELD
LONG TERM....MK
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1038 AM EDT FRI JUL 20 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 356 AM EDT FRI JUL 20 2012
AS A COLD FRONT AND WEAK SURFACE LOW DEPART THE AREA TODAY...A
WEAK SHORTWAVE WILL TRAVERSE THE REGION. THIS WILL HAVE A SMALL
CHANCE OF SPARKING AN ADDITIONAL SHOWER OR TWO THIS MORNING BEFORE
DRY WEATHER RETURNS TO THE FORECAST THROUGH THE WEEKEND.
ADDITIONALLY...SKIES WILL BE MOSTLY CLOUDY THROUGH THE FIRST HALF
OF THE DAY AS STRATOCUMULUS BUILDS INTO THE AREA IN THE CYCLONIC
FLOW. THIS WILL ALSO HELP KEEP TEMPERATURES DOWN TODAY...WITH SOME
AREAS STRUGGLING TO EVEN REACH THE 80 DEGREE MARK...A MAJOR SHIFT
FROM RECENT RECORD BREAKING HEAT. UNFORTUNATELY...THIS RESPITE
WILL BE SHORT LIVED...AS A RAPID WARMING TREND WILL FOLLOW FOR THE
WEEKEND...WITH TEMPERATURES BACK WELL INTO THE MID 90S BY SUNDAY
AS RIDGING ONCE AGAIN ASSERTS DOMINANCE ACROSS THE AREA. NORTHWEST
FLOW ALOFT NEXT WEEK SUGGESTS ONE OR MORE CHANCES FOR
THUNDERSTORMS...BUT PROBABILITIES REMAIN LOW AND UNCERTAIN AT THE
MOMENT.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1039 AM EDT FRI JUL 20 2012
ISOLATED SHOWERS AND SPRINKLES ARE TAKING THEIR TIME ABOUT GOING
AWAY. RUC ISNT IN ANY RUSH TO GET RID OF THEM. WILL UPDATE TO KEEP
SOME PRECIP THROUGH MOST OF AFTERNOON. CURRENT POPS STILL LOOK
GOOD...BUT WILL MENTION ISOLATED SPRINKLES WEST.
TAKING TEMPS DOWN A CAT IN THE EAST AND CENTRAL WITH PRECIP AND
CLOUDS HANGING ON LONGEST THERE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 356 AM EDT FRI JUL 20 2012
WITH SURFACE HIGH PRESSURE THE DOMINANT FEATURE THROUGHOUT THE
SHORT TERM...TEMPERATURES ARE THE ONLY SIGNIFICANT FORECAST ISSUE.
MODEL 850 TEMPS WARM SIGNIFICANTLY AND QUICKLY THROUGH THE SHORT
TERM...AND ARE BACK INTO THE LOW 20C RANGE BY SUNDAY.
LATELY...THIS HAS TRANSLATED EASILY INTO THE MID 90S...AND WHILE
RECENT RAINFALL HAS MADE A SMALL DENT INTO EXTREME DROUGHT...IT
WILL TAKE MUCH MORE THAN WHAT HAS ALREADY OCCURRED TO MITIGATE
IMPACT OF DROUGHT ON TEMPERATURES. EXPECT WE WILL BEGIN TO EASILY
OUTPACE MOS ONCE AGAIN. GENERALLY RAISED CONSENSUS AT LEAST A
COUPLE OF DEGREES ON MAXES...WITH CORRESPONDING BUT SLIGHTLY
SMALLER HIKES DURING THE OVERNIGHTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 255 AM EDT FRI JUL 20 2012
LONG RANGE MODELS AND ENSEMBLES SUGGEST UPPER RIDGE ACROSS THE
PLAINS EARLY NEXT WEEK WILL SETTLE SOUTHEAST ACROSS THE SOUTHERN
STATES MIDWEEK WITH CENTRAL INDIANA ON THE SOUTHERN FRINGES OF THE
WESTERLIES. MODELS ALSO HAVE QPF THROUGH MUCH OF THE EXTENDED.
UPPER THICKNESS PATTERN IS CONDUCIVE TO PERIODIC NORTHWEST TO
SOUTHEAST MOVING THUNDERSTORM COMPLEXES ACROSS THE LOWER GREAT LAKES
AND OHIO VALLEY...SO WILL LEAVE AT LEAST SMALL CHANCE POPS
THROUGHOUT THE EXTENDED. KEPT AFTERNOON TEMPERATURES A FEW DEGREES
ABOVE MOS AND THE CENTRAL REGION INITIALIZATION AS WE STILL HAVE A
WAY TO GO BEFORE THE DROUGHT LOSES ITS IMPACT.
&&
.AVIATION /DISCUSSION FOR THE 201500Z KIND TAF UPDATE.../
ISSUED AT 1012 AM EDT FRI JUL 20 2012
SURFACE TROUGH HAS PASSED THROUGH KIND...WITH AN ASSOCIATED WIND
SHIFT TO 010-030 DEGREES. IFR CEILINGS...ALONG WITH A FEW AREAS OF
IFR VISIBILITY RESTRICTIONS IN LIGHT RAIN/DRIZZLE/LIGHT FOG EXIST
BEHIND THE WIND SHIFT. THESE CONDITIONS EXPECTED TO CONTINUE FROM
TIME TO TIME AT KIND INTO THE EARLY AFTERNOON HOURS...ROUGHLY
201700Z. DRIER AIR WORKING IN AT THE LOWER LEVELS COMBINED WITH WEAK
BOUNDARY LAYER HEATING...SHOULD ALLOW FOR CEILINGS TO RISE THROUGH
THE MVFR CATEGORY AND EVENTUALLY VFR LATER THIS AFTERNOON. WILL BUMP
BACK THE CEILING/VISIBILITY IMPROVEMENT BACK A COUPLE OF HOURS IN
THE UPDATE. PREVIOUS DISCUSSION FOLLOWS.
SATELLITE AND OBSERVATION TRENDS ALONG WITH MODELS SUGGEST MVFR AND
POSSIBLY IFR CONDITIONS EXPECTED THROUGH 19Z. AFTER THAT...CEILINGS
SHOULD COME UP TO VFR AND START BREAKING UP WITH CLEARING AFTER 00Z.
NORTHEAST WINDS 10 KNOTS OR SLIGHTLY MORE TODAY WILL BECOME LIGHT TO
CALM AFTER DARK. THIS COULD LEAD TO SOME MVFR OR WORSE FOG
OVERNIGHT. HOWEVER...A DRY DAY TODAY ALONG WITH DEW POINTS
DECREASING TO THE UPPER 50S AND LOWER 60S TONIGHT MAY KEEP IT P6SM.
WITH CONFIDENCE LOW...AND WITH IT THAT FAR OUT...WILL LEAVE FOG OUT
FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...JK
SHORT TERM...NIELD
LONG TERM....MK
AVIATION...MK/JAS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1034 PM CDT SAT JUL 21 2012
.UPDATE...
CONVECTION HAS ALREADY EXPANDED ACROSS FAR SRN SD AND SRN MN SO HAVE
UPPED PRECIP CHANCES FAR NORTH.
PREVIOUS UPDATE...NO APPRECIABLE CHANGES TO FORECAST TONIGHT. WAS
SOME CONCERN REGARDING FATE OF SMALL CONVECTIVE CLUSTER APPROACHING
YANKTON AS IT RODE TOP OF ELEVATED MIXED LAYER...BUT THAT CONTINUES
TO DISSIPATE. EXAMINATION OF RAP ELEVATED INSTABILITY LAYERS
SUGGESTS MOST FAVORABLE CAPE/CIN ALOFT CONTINUES TO LIFT NORTHWARD
INTO SD AND MN OVERNIGHT. THIS APPEARS TO BE COINCIDENT WITH SHARP
BAROCLINIC ZONE NOTED ALONG RAP 315K ISENT SURFACE. STRONG UVM AND
MOISTURE CONVERGENCE IS NOTED ON NOSE OF 30-40KT FLOW AFTER MIDNIGHT
WITH ISENT SURFACE CHANGING FROM 900-700MB ALONG TRAJECTORY FROM
CENTRAL NE INTO SWRN MN. WITH THIS IN MIND EXPECT CURRENT WRN SD
MCS TO EXPAND EASTWARD EARLY SUN MORNING...AND/OR AN INCREASE OF
CURRENT ELEVATED SHOWERS FESTERING OVER SRN MN. MAY EVEN SEE SOME
SORT OF CONNECTION. SEVERAL SUPPORTING WRF RUNS AND THE LATEST HRRR
FOCUS ALONG THE SD/MN BORDER...WITH THE HRRR EVEN BLOSSOMING
CONVECTION INTO IA OVERNIGHT. FEEL THIS IS TOO AGGRESSIVE SOUTH
CONSIDERING THE MEAN WIND BEING MORE EAST THAN SOUTH...BUT SEE NO
REASON TO CHANGE CURRENT OVERNIGHT LOW POPS NORTH AT THIS POINT.
&&
.SHORT TERM /TONIGHT/...
SERIES OF VORTICITY CENTERS TUMBLING DOWN EAST SIDE OF UPPER RIDGE
AND SOME MID-LEVEL WARM ADVECTION HAVE KEPT SHOWERS GOING INTO THE
AFTERNOON ACROSS NORTHERN AND EASTERN IOWA. ASSOCIATED SPILLAGE OF
CLOUDS FARTHER SOUTH HELD DOWN HIGH TEMPERATURES SOMEWHAT TODAY BUT
DID NOT PRODUCE ANY BENEFICIAL RAINFALL. IT APPEARS THE PATTERN
WON`T CHANGE MUCH OVERNIGHT...AND WITH ANOTHER VORTICITY CENTER
SHOWING UP NEAR THE BLACK HILLS AND ANOTHER SURGE OF 850 MB WINDS
OVERNIGHT...CONVECTION SHOULD DEVELOP AGAIN NEAR THE MINNESOTA
BORDER BY MIDNIGHT OR SO. AGAIN...THIS SHOULD NOT BE VERY INTENSE
AND WILL REMAIN ELEVATED...BUT IT WILL HAVE CONSEQUENCES FOR CLOUD
COVER INTO SUNDAY. LIGHT SOUTH FLOW WILL PERSIST OVERNIGHT AT THE
SURFACE WITH THE LOW PRESSURE CENTER REMAINING IN SOUTH DAKOTA. TO
THIS POINT...THE SOUTH WINDS ARE NOT BRINGING IN A LOT OF
HUMIDITY...EXCEPT IN NORTHERN IOWA NEARER THE SURFACE BOUNDARY WHICH
IS POSITIONED IN SOUTHERN MINNESOTA. AS A RESULT...LOW TEMPERATURES
SHOULD DROP TO NEAR 70 DEGREES IN MOST LOCATIONS WITH THE EXCEPTION
OF THE DES MOINES AND CENTRAL IOWA HEAT ISLANDS.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
FORECAST CONCERNS IN THE EXTENDED REVOLVE AROUND WHERE THE
CONVECTION AND CLOUDS WILL HAMPER TEMPS AND AFFECT THE EXCESSIVE
HEAT WARNING. THE EFFECTS OF WHICH WERE MADE EVIDENT TODAY. THE
MODELS ARE CONSISTENT IN KEEPING SHORTWAVES RIDGING OVER THE
PERIPHERY OF THE UPPER LEVEL RIDGE. MODELS ARE CONSISTENT IN
DEVELOPING STORMS OVER SOUTHERN MINNESOTA AND CORFIDI VECTORS DROP
THE STORMS INTO NORTHERN/EASTERN IOWA...MUCH LIKE TODAY...EXCEPT
THAT THE SOUTHERN EXTEND OF THE STORMS IS A BIT MORE IN QUESTION.
NONE THE LESS...CLOUD COVER WILL BE OVER THE AREA AND AFFECT THE
TEMPS. HEAT INDICES...ESPECIALLY ACROSS THE SOUTH AND WEST...WHILE
A LITTLE LOWER ARE STILL IN THE 101-106 RANGE. THIS FALLS A BIT
SHORT OF THE WARNING CRITERIA BUT IF WE GET A LITTLE MORE SUN OR
THE STORMS DON`T EVOLVE AS FAR SOUTH THEN WE WILL HAVE NO PROBLEM
HEATING UP. MY CONFIDENCE IS NOT HIGH ENOUGH TO CHANGE THE WARNING
AT THIS POINT. THERE IS ONE EXCEPTION...NORTH OF HIGHWAY 20 IS THE
MOST UNLIKELY AREA TO SEE EXCESSIVE HEAT. SHOWERS/CLOUDS WILL
PLAGUE THIS AREA JUST ABOUT EVERY DAY OF THE WARNING. FOR THIS
REASON I HAVE DROPPED THE WARNING NORTH OF HIGHWAY 20 WHICH
AMOUNTS TO ONE TIER OF COUNTIES.
MONDAY AND TUESDAY DEFINITELY LOOK LIKE THE HOTTEST DAYS OF THE
WEEK SO LITTLE CHANGES MADE TO THE FORECAST HERE EXCEPT TO TWEAK
TEMPS A BIT.
FOR WEDNESDAY A STRONG UPPER LEVEL LOW TRAVELING ACROSS SOUTHERN
CANADA WILL FLATTEN THE RIDGE WHILE AT THE SURFACE A WEAK COLD
FRONT WILL SHIFT ACROSS THE FORECAST AREA. THERE IS DECENT FORCING
ALONG THE BOUNDARY AND OFFERS OUR BEST CHANCE AT SEEING
CLOUDS/STORMS. TIMING OF THE BOUNDARY AT THIS POINT REMAINS IN
QUESTION WHICH PUTS INTO QUESTION WHETHER WE WILL NEED AN
EXCESSIVE HEAT WARNING FOR WEDNESDAY BUT AGAIN...MY CONFIDENCE IS
NOT HIGH ENOUGH TO DROP IT FOR THE PERIOD SO I WILL LET IT RIDE
FOR NOW. HOWEVER...I DID INCREASE POPS/CLOUDS AND KNOCK TEMPS
BACK A BIT. THE SAME LOGIC IS APPLIED FOR THIS PERIOD AS WELL. WE
FALL A BIT SHY ON THE CRITERIA BUT IF WE GET A BIT MORE SUN OR THE
FRONT SLOWS...WE WILL HAVE NO PROBLEM REACHING CRITERIA.
AS FOR THE REST OF THE EXTENDED...THE RIDGE REBUILDS TO OUR WEST
PUTTING US IN A MORE NW FLOW WITH WEAK HIGH PRESSURE AT THE
SURFACE. THIS WILL BRING A BREAK TO THE HEAT AND ACTUALLY PRODUCE
HIGHS THAT ARE MORE SEASONAL. HIGHS BY NEXT WEEKEND WILL BE IN THE
MID TO UPPER 80S WHICH WILL BE A WELCOME RELIEF TO WHAT WE HAVE HAD.
&&
.AVIATION...22/00Z
SIMILAR TO YESTERDAY...PRIMARILY VFR CONDITIONS ANTICIPATED WITH
NOTHING MORE THAN INTERMITTENT MID CLOUD CIGS. THERE IS SOME
POTENTIAL FOR SHOWERS AND THUNDERSTORMS NORTH OVERNIGHT AS SCATTERED
HIGH PLAINS CONVECTION CONTINUES TO TOP UPPER LEVEL RIDGE. HAVE
INCLUDED A PERIOD OF VCSH WORDING AT MCW FOR NOW...BUT CONFIDENCE
NOT GREAT ENOUGH AT THE MOMENT TO INCLUDE OTHER SITES OR ADD
THUNDER.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING UNTIL 3PM WED
ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-
CRAWFORD-DALLAS-DECATUR-GREENE-GUTHRIE-HAMILTON-JASPER-LUCAS-MADISON-
MARION-MONROE-POLK-RINGGOLD-SAC-STORY-TAYLOR-UNION-WARREN-WAYNE-
WEBSTER
EXCESSIVE HEAT WARNING FROM 1PM SUN TO 3PM WED
BLACK HAWK-DAVIS-GRUNDY-HARDIN-MAHASKA-MARSHALL-POWESHIEK-TAMA-
WAPELLO
&&
$$
LONG TERM...FAB
SHORT TERM...JUNGBLUTH
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
947 PM CDT SAT JUL 21 2012
.UPDATE...
NO APPRECIABLE CHANGES TO FORECAST TONIGHT. WAS SOME CONCERN
REGARDING FATE OF SMALL CONVECTIVE CLUSTER APPROACHING YANKTON AS IT
RODE TOP OF ELEVATED MIXED LAYER...BUT THAT CONTINUES TO DISSIPATE.
EXAMINATION OF RAP ELEVATED INSTABILITY LAYERS SUGGESTS MOST
FAVORABLE CAPE/CIN ALOFT CONTINUES TO LIFT NORTHWARD INTO SD AND MN
OVERNIGHT. THIS APPEARS TO BE COINCIDENT WITH SHARP BAROCLINIC ZONE
NOTED ALONG RAP 315K ISENT SURFACE. STRONG UVM AND MOISTURE
CONVERGENCE IS NOTED ON NOSE OF 30-40KT FLOW AFTER MIDNIGHT WITH
ISENT SURFACE CHANGING FROM 900-700MB ALONG TRAJECTORY FROM CENTRAL
NE INTO SWRN MN. WITH THIS IN MIND EXPECT CURRENT WRN SD MCS TO
EXPAND EASTWARD EARLY SUN MORNING...AND/OR AN INCREASE OF CURRENT
ELEVATED SHOWERS FESTERING OVER SRN MN. MAY EVEN SEE SOME SORT OF
CONNECTION. SEVERAL SUPPORTING WRF RUNS AND THE LATEST HRRR FOCUS
ALONG THE SD/MN BORDER...WITH THE HRRR EVEN BLOSSOMING CONVECTION
INTO IA OVERNIGHT. FEEL THIS IS TOO AGGRESSIVE SOUTH CONSIDERING
THE MEAN WIND BEING MORE EAST THAN SOUTH...BUT SEE NO REASON TO
CHANGE CURRENT OVERNIGHT LOW POPS NORTH AT THIS POINT.
&&
.SHORT TERM /TONIGHT/...
SERIES OF VORTICITY CENTERS TUMBLING DOWN EAST SIDE OF UPPER RIDGE
AND SOME MID-LEVEL WARM ADVECTION HAVE KEPT SHOWERS GOING INTO THE
AFTERNOON ACROSS NORTHERN AND EASTERN IOWA. ASSOCIATED SPILLAGE OF
CLOUDS FARTHER SOUTH HELD DOWN HIGH TEMPERATURES SOMEWHAT TODAY BUT
DID NOT PRODUCE ANY BENEFICIAL RAINFALL. IT APPEARS THE PATTERN
WON`T CHANGE MUCH OVERNIGHT...AND WITH ANOTHER VORTICITY CENTER
SHOWING UP NEAR THE BLACK HILLS AND ANOTHER SURGE OF 850 MB WINDS
OVERNIGHT...CONVECTION SHOULD DEVELOP AGAIN NEAR THE MINNESOTA
BORDER BY MIDNIGHT OR SO. AGAIN...THIS SHOULD NOT BE VERY INTENSE
AND WILL REMAIN ELEVATED...BUT IT WILL HAVE CONSEQUENCES FOR CLOUD
COVER INTO SUNDAY. LIGHT SOUTH FLOW WILL PERSIST OVERNIGHT AT THE
SURFACE WITH THE LOW PRESSURE CENTER REMAINING IN SOUTH DAKOTA. TO
THIS POINT...THE SOUTH WINDS ARE NOT BRINGING IN A LOT OF
HUMIDITY...EXCEPT IN NORTHERN IOWA NEARER THE SURFACE BOUNDARY WHICH
IS POSITIONED IN SOUTHERN MINNESOTA. AS A RESULT...LOW TEMPERATURES
SHOULD DROP TO NEAR 70 DEGREES IN MOST LOCATIONS WITH THE EXCEPTION
OF THE DES MOINES AND CENTRAL IOWA HEAT ISLANDS.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
FORECAST CONCERNS IN THE EXTENDED REVOLVE AROUND WHERE THE
CONVECTION AND CLOUDS WILL HAMPER TEMPS AND AFFECT THE EXCESSIVE
HEAT WARNING. THE EFFECTS OF WHICH WERE MADE EVIDENT TODAY. THE
MODELS ARE CONSISTENT IN KEEPING SHORTWAVES RIDGING OVER THE
PERIPHERY OF THE UPPER LEVEL RIDGE. MODELS ARE CONSISTENT IN
DEVELOPING STORMS OVER SOUTHERN MINNESOTA AND CORFIDI VECTORS DROP
THE STORMS INTO NORTHERN/EASTERN IOWA...MUCH LIKE TODAY...EXCEPT
THAT THE SOUTHERN EXTEND OF THE STORMS IS A BIT MORE IN QUESTION.
NONE THE LESS...CLOUD COVER WILL BE OVER THE AREA AND AFFECT THE
TEMPS. HEAT INDICES...ESPECIALLY ACROSS THE SOUTH AND WEST...WHILE
A LITTLE LOWER ARE STILL IN THE 101-106 RANGE. THIS FALLS A BIT
SHORT OF THE WARNING CRITERIA BUT IF WE GET A LITTLE MORE SUN OR
THE STORMS DON`T EVOLVE AS FAR SOUTH THEN WE WILL HAVE NO PROBLEM
HEATING UP. MY CONFIDENCE IS NOT HIGH ENOUGH TO CHANGE THE WARNING
AT THIS POINT. THERE IS ONE EXCEPTION...NORTH OF HIGHWAY 20 IS THE
MOST UNLIKELY AREA TO SEE EXCESSIVE HEAT. SHOWERS/CLOUDS WILL
PLAGUE THIS AREA JUST ABOUT EVERY DAY OF THE WARNING. FOR THIS
REASON I HAVE DROPPED THE WARNING NORTH OF HIGHWAY 20 WHICH
AMOUNTS TO ONE TIER OF COUNTIES.
MONDAY AND TUESDAY DEFINITELY LOOK LIKE THE HOTTEST DAYS OF THE
WEEK SO LITTLE CHANGES MADE TO THE FORECAST HERE EXCEPT TO TWEAK
TEMPS A BIT.
FOR WEDNESDAY A STRONG UPPER LEVEL LOW TRAVELING ACROSS SOUTHERN
CANADA WILL FLATTEN THE RIDGE WHILE AT THE SURFACE A WEAK COLD
FRONT WILL SHIFT ACROSS THE FORECAST AREA. THERE IS DECENT FORCING
ALONG THE BOUNDARY AND OFFERS OUR BEST CHANCE AT SEEING
CLOUDS/STORMS. TIMING OF THE BOUNDARY AT THIS POINT REMAINS IN
QUESTION WHICH PUTS INTO QUESTION WHETHER WE WILL NEED AN
EXCESSIVE HEAT WARNING FOR WEDNESDAY BUT AGAIN...MY CONFIDENCE IS
NOT HIGH ENOUGH TO DROP IT FOR THE PERIOD SO I WILL LET IT RIDE
FOR NOW. HOWEVER...I DID INCREASE POPS/CLOUDS AND KNOCK TEMPS
BACK A BIT. THE SAME LOGIC IS APPLIED FOR THIS PERIOD AS WELL. WE
FALL A BIT SHY ON THE CRITERIA BUT IF WE GET A BIT MORE SUN OR THE
FRONT SLOWS...WE WILL HAVE NO PROBLEM REACHING CRITERIA.
AS FOR THE REST OF THE EXTENDED...THE RIDGE REBUILDS TO OUR WEST
PUTTING US IN A MORE NW FLOW WITH WEAK HIGH PRESSURE AT THE
SURFACE. THIS WILL BRING A BREAK TO THE HEAT AND ACTUALLY PRODUCE
HIGHS THAT ARE MORE SEASONAL. HIGHS BY NEXT WEEKEND WILL BE IN THE
MID TO UPPER 80S WHICH WILL BE A WELCOME RELIEF TO WHAT WE HAVE HAD.
&&
.AVIATION...22/00Z
SIMILAR TO YESTERDAY...PRIMARILY VFR CONDITIONS ANTICIPATED WITH
NOTHING MORE THAN INTERMITTENT MID CLOUD CIGS. THERE IS SOME
POTENTIAL FOR SHOWERS AND THUNDERSTORMS NORTH OVERNIGHT AS SCATTERED
HIGH PLAINS CONVECTION CONTINUES TO TOP UPPER LEVEL RIDGE. HAVE
INCLUDED A PERIOD OF VCSH WORDING AT MCW FOR NOW...BUT CONFIDENCE
NOT GREAT ENOUGH AT THE MOMENT TO INCLUDE OTHER SITES OR ADD
THUNDER.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING UNTIL 3PM WED
ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-
CRAWFORD-DALLAS-DECATUR-GREENE-GUTHRIE-HAMILTON-JASPER-LUCAS-MADISON-
MARION-MONROE-POLK-RINGGOLD-SAC-STORY-TAYLOR-UNION-WARREN-WAYNE-
WEBSTER
EXCESSIVE HEAT WARNING FROM 1PM SUN TO 3PM WED
BLACK HAWK-DAVIS-GRUNDY-HARDIN-MAHASKA-MARSHALL-POWESHIEK-TAMA-
WAPELLO
&&
$$
LONG TERM...FAB
SHORT TERM...JUNGBLUTH
AVIATION...SMALL
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
230 PM CDT FRI JUL 20 2012
.MESOSCALE UPDATE...CONCERNING THUNDERSTORM DEVELOPMENT AND SEVERE
WEATHER POTENTIAL THIS AFTERNOON...
AS OF 2 PM THIS AFTERNOON...RATHER COMPLEX SURFACE FRONTAL ZONE
AND ASSOCIATED BOUNDARY LAYER MASS CONVERGENCE AXIS CONTINUE TO
MOVE SOUTHEASTWARD ACROSS NORTHWEST MINNESOTA. MAIN CONVERGENCE
AXIS AND INITIAL WIND SHIFT EXTENDS FROM BETWEEN FARGO AND GRAND
FORKS TO JUST WEST OF INTERNATIONAL FALLS...WITH A NARROW AXIS OF
DRIER AIR WORKING EASTWARD ALONG THE IMMEDIATE WIND SHIFT LINE.
HOWEVER..RICH BOUNDARY LAYER MOISTURE WITH DEWPOINTS IN THE UPPER
60S TO LOWER 70S EXISTS OVER MUCH OF THE DULUTH CWA AHEAD OF THIS
LOCAL DRYING PLUME..AND THERE IS ALSO A NARROW ZONE OF RICH BOUNDARY
LAYER MOISTURE JUST BEHIND THE FRONT OVER FAR NW/NCENT MN WHERE
BOUNDARY LAYER CUMULUS HAS RAPIDLY DEVELOPED OVER THE PAST HOUR OR
SO.
THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY AS TO EXACTLY WHERE AND
WHEN DEEP CONVECTION MIGHT DEVELOP THIS AFTERNOON WITH CONSIDERABLE
SPREAD STILL IN THE SHORT RANGE HI-RESOLUTION GUIDANCE THROUGH THIS
EVENING. LOCAL DLH WRF SUGGESTS SVR STORMS WILL DEVELOP IN THE RED
LAKE TO KINL AREA BETWEEN 3-4 PM AND THEN MAINTAIN FOR SEVERAL HOURS
WHILE MOVING SEWD ACROSS THE CENTRAL SRN PORTIONS OF THE DLH CWA.
HOWEVER..SEVERAL OTHER MODELS SUGGEST NOT MUCH IN THE WAY OF DEEP
CONVECTION AT ALL WITH A MAINLY DRY FRONTAL PASSAGE.
GIVEN THE APPROACHING UPPER LEVEL SPEED MAX AND WEAK WAVE AS
EVIDENCED IN UPPER LEVEL RAP PV OBJECTIVE ANALYSIS FIELDS..AND THE
STRENGTH OF THE INSTABILITY PRESENT IT SEEMS A LITTLE BIT OF A
STRETCH THAT NO STORMS AT ALL WOULD FORM. THE GREATEST RISK OF
STRONG/SVR TSTORM DEVELOPMENT APPEARS TO BE BETWEEN THE WALKER/RED
LAKE/INTERNATIONAL FALLS/VOYAGEURS NATIONAL PARK AREA BETWEEN 3-5
PM..WITH A GENERAL SOUTHEAST MOVEMENT THEREAFTER INTO THE CORRIDOR
FROM BRAINERD/WALKER NEWD TO THE IRON RANGE AND ELY BY EARLY
EVENING.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
MILLER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
641 AM CDT FRI JUL 20 2012
.UPDATE...FOR 12Z AVIATION DISCUSSION BELOW...
&&
.DISCUSSION.../ISSUED 414 AM CDT FRI JUL 20/
CURRENT H5 ANALYSIS SHOWS 597 DM H5 RIDGE NOW FIRMLY IN PLACE
ACROSS THE CENTRAL HIGH PLAINS...WITH 594 DM HEIGHTS ALL THE WAY
UP INTO CENTRAL SODAK. THERE IS A WEAK SHORTWAVE...REALLY SERIES
OF SHORT WAVES ROUNDING THE RIDGE ACROSS THE DAKOTAS THIS MORNING.
THIS HAS RESULTED IN THE DEVELOPMENT OF A WEAK LLJ AND MOIST
ISENTROPIC ASCENT ACROSS THE ERN DAKOTAS...WHERE SCT STORMS HAVE
BEEN SLOWLY INCREASING IN COVERAGE OVERNIGHT. AT THE SFC...A
RATHER WEAK AND DIFFUSE BOUNDARY STRETCHES FROM WINNIPEG DOWN
TOWARD BISMARK AND OFF INTO NW SODAK.
STILL LOOKS LIKE UPPER AIR PATTERN WILL NOT CHANGE A WHOLE LOT
THIS PERIOD...WITH UPPER RIDGE CONTINUING TO DOMINATE THE CENTER
OF THE COUNTRY FOR THE NEXT WEEK...WHILE OCCASIONAL SHORT WAVES
RIPPLE ACROSS SRN CANADA. MOST SUBSTANTIAL OF THESE WAVES HAS BEEN
SPINNING OFF THE BC COAST THE LAST FEW DAYS...WHICH THE GFS AND
ECMWF CONTINUE TO SEND ACROSS THE INTERNATIONAL BORDER MID WEEK.
IN FACT...LATEST CFS FORECAST WOULD INDICATE THERE WILL NOT BE
MUCH CHANGE TO THIS STATUS QUO OUT FOR THE NEXT 4 WEEKS. IF THIS
ENDS UP BEING THE CASE...THEN THE RECORD FOR WARMEST JULY ON
RECORD IN THE TWIN CITIES /1936/ MAY VERY WELL END UP BEING IN
JEOPARDY.
FOR TODAY...EXPECT CONVECTION JUST OFF TO OUR WEST TO SLOWLY WORK
EAST THIS MORNING...MOVING INTO WEST CENTRAL MN AROUND 12Z.
HOWEVER...DIURNAL WEAKENING OF THE LLJ SHOULD ALLOW FOR A FAIRLY
RAPID DECREASE IN STORM INTENSITY/COVERAGE...NOT TO MENTION THIS
ACTIVITY WILL BE MOVING INTO DRIER/LESS UNSTABLE AIR AS IT WORKS
EAST. MOST HI-RES MODELS ALONG WITH SREF PROBS HIGHLIGHT THIS IDEA
OF ACTIVITY WORKING INTO THE WRN CWA THIS MORNING...ONLY TO
QUICKLY DIE OFF ONCE IT GETS HERE. FOR THE AFTERNOON...EXPECT
ADDITIONAL ISO/SCT CONVECTION TO BE MAINLY NORTH OF THE MPX AREA
ALONG THE BOUNDARY...WITHIN A POOL OF 3000-3500 J/KG OF MLCAPE
INDICATED BY THE NAM FROM NE SODAK THROUGH THE FARGO AREA AND UP
TOWARD INL. GOING THROUGH THE NIGHT...ANY OF THIS ACTIVITY WILL
BEGIN TO SLOWLY SAG SOUTH INTO THE AREA AS BOTH THE BOUNDARY AND
LLJ /AS WEAK AS IT IS/ WORK INTO CENTRAL MN. WITH THE LLJ SLOWLY
PUSHING SOUTH THROUGH THE MPX AREA OVERNIGHT...WOULD SUSPECT AT
LEAST SOME CONVECTION TO DEVELOP AS WE HAVE SEEN ACROSS THE
DAKOTAS THIS EVENING WITH IN THE LLJ. HOWEVER...INSTABILITY FRI
NIGHT WILL BE MUCH WEAKER THAN WHAT IS CURRENTLY BEING SEEN OVER
THE DAKOTAS...SO COVERAGE SHOULD NOT BE AS GREAT. GIVEN PROXIMITY
TO THE UPPER RIDGE...SHEAR WILL CONTINUE TO BE WEAK...SO NOT
ANTICIPATING ANY WIDESPREAD SVR THREAT UNLESS CONVECTION CAN GET
ORGANIZED INTO A SEMI-LINEAR SYSTEM AT SOME POINT. GOING INTO
SATURDAY...FOCUS FOR VERY SMALL THUNDER CHANCES WILL PUSH INTO THE
SRN PART OF THE CWA AS THE WEAK BOUNDARY PUSHES INTO IA.
FOR HIGHS THIS AFTERNOON...SHOULD SEE A NICE GRADIENT IN VALUES
FROM WEST TO EAST ACROSS THE AREA. NAM/ECMWF SHOWS 925-850 MB LAYER
TEMPS INCREASING TO AROUND 30C THIS AFTERNOON IN WEST CENTRAL MN.
VALUES THIS HIGH YESTERDAY YIELDED HIGHS WELL INTO THE 100S ACROSS
THE DAKOTAS...SO BUMPED UP HIGHS A FEW DEGREES IN FAR WRN SECTIONS
OF THE CWA. ASSUMING UPPER CLOUDS DO NOT SPOIL THE PARTY...FULLY
EXPECT PLACES OUT AROUND MADISON TO MAKE A RUN AT 100 TODAY. OVER
WRN WI...TEMPS IN THE 925-850 LAYER WILL BE DOWN CLOSE TO
22C...AND MIXING THESE DOWN TO THE SFC YIELDS HIGHS ONLY IN THE
MID 80S. GOING INTO SATURDAY...NAM/ECMWF SHOW THE WARM AIR PUSHING
SOUTH OF HERE AND LOOKS LIKE MOST OF THE AREA WILL SEE A BREAK
FROM HIGHS IN THE 90S ON SATURDAY...BEFORE THEY COME BACK SUNDAY.
FOR SUNDAY THROUGH MONDAY NIGHT...THE MPX AREA STILL LOOKS TO BE
PERCHED ON THE N/NE EDGE OF THE UPPER RIDGE AND ASSOCIATED
CAP...BUT FORCING FOR ANY CONVECTION BASED ON H85 LLJ/MOISTURE
TRANSPORT FORECASTS LOOKS TENUOUS AT BEST AND WOULD SUSPECT THIS
PERIOD TO BE PRETTY MUCH DRY. IN ADDITION TO THE DRY WX...HIGHS
SHOULD HAVE NO PROBLEM FINDING THEIR WAY BACK INTO THE 90S FOR ALL
BUT THE NRN FRINGE OF THE MPX CWA.
TUESDAY THROUGH THURSDAY PERIOD WILL SEE A WEAKENING/FLATTENING
OUT OF THE UPPER RIDGE AS A STRONG SHORT WAVE MOVES ACROSS SRN
CANADA. WITH THE 20.00 RUNS...THE GFS/ECMWF ARE SHOWING A BIT MORE
DISAGREEMENT WITH THIS SYSTEM...WITH THE ECMWF RUNNING ABOUT 12-18
HOURS FASTER THAN THE GFS. BIGGEST IMPACT WITH THIS IS THAT AN
ECMWF SOLUTION WOULD BRING AN END TO THE PRECIP THURSDAY...WHILE
THE GFS KEEPS THE FRONT AND ASSOCIATED PRECIP AROUND INTO FRIDAY.
BEST CHANCE FOR PRECIP IN THIS PERIOD STILL LOOKS TO BE TUESDAY
AFTERNOON INTO TUESDAY NIGHT AS A WARM FRONT SHARPENS ACROSS THE
MPX AREA AND SLOWLY LIFTS NORTHEAST. ABOUT THE ONLY THING THAT
WOULD KEEP HIGHS OUT OF THE 90S DURING THIS DAYS IS EXTENSIVE
CLOUD COVER/PRECIP NORTH OF THE BOUNDARY TUESDAY...BUT SHOULD BE A
GOOD OPPORTUNITY TO CONTINUE PILING UP THE 90 DEGREE HIGHS ACROSS
MUCH OF THE AREA. THE ECMWF DOES NOT INDICATE THE POTENTIAL FOR
90 DEGREE HIGHS LEAVING THE AREA UNTIL THE END OF THE WEEK...AND
EVEN THEN IT ONLY PUSHES THEM OVER TO IA AND SODAK.
&&
.AVIATION.../12Z TAF ISSUANCE/
SHOWER AND THUNDERSTORM CHANCES ARE THE MAIN FORECAST CONCERN
THIS TAF PERIOD. THE 20.08 HRRR CONTINUED TO DEPICT THE
ADVANCEMENT OF SHRA/TS ACTIVITY OVER EASTERN SD ACROSS THE TAF
AREA TODAY. HOWEVER...ITS INITIALIZATION WAS RELATIVELY POOR...SO
OPTED NOT TO INCLUDE MID-DAY SHRA/TS AT KMSP/KRNH/KEAU AS THE
SOLUTION WOULD SUGGEST. DID HOWEVER INCLUDE A MENTION OF SHRA/TS
AT KAXN/KSTC/KRWF TODAY...AS THE SHORTWAVE OVER ERN SD IS
DETECTABLE IN MORNING RADAR IMAGERY. H85-H7 THETA E ADVECTION
WANES NOTABLY THIS MORNING HOWEVER...SO ANTICIPATE GRADUAL
DECAYING OF THE CURRENT ACTIVITY...AND VICINITY VERBAGE SHOULD BE
SUFFICIENT FOR THE MOST PART. TONIGHT WILL BRING ANOTHER
OPPORTUNITY FOR CONVECTIVE DEVELOPMENT AS THE LLJ RAMPS UP AGAIN.
HAVE INCLUDED PROB30 GROUPS FOR KMSP/KEAU/KRNH AFTER 05Z SAT.
SOUTHERLY WINDS INCREASING TODAY...WITH SUSTAINED SPEEDS AROUND 10
KNOTS AND GUSTS INTO THE MID/UPPER TEENS /KNOTS/.
KMSP...VFR EXPECTED TODAY. WHILE AN ISOLATED SHOWER OR
THUNDERSTORM CANNOT BE RULED OUT TODAY...CONFIDENCE AND
PROBABILITY ARE TOO LOW TO INCLUDE IT IN THE TAF DURING THE
DAYTIME. TONIGHT WILL BRING A SLIGHTLY HIGHER CHANCE AS THE LLJ
INCREASES...SO HAVE INCLUDED A PROB30 AFTER 05Z SAT. SOUTHERLY
WINDS WILL PREVAIL THROUGH TONIGHT...WITH A SHIFT TO SOUTHWESTERLY
OCCURRING AROUND/AFTER 12Z SAT.
/OUTLOOK/
SATURDAY...VFR WITH A 20 PERCENT CHANCE OF TSRA. WINDS N AT 10-15KTS.
SUNDAY...VFR WITH A 20 PERCENT CHANCE OF TSRA. WINDS S AT 5-10KTS.
MONDAY...VFR. WINDS NW AT 5-10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LRS/MPG
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1120 PM CDT THU JUL 19 2012
.SHORT TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(TONIGHT)
`COLD` FRONT IS DRIFTING THROUGH THE NORTHERN PORTION OF THE CWFA
THIS AFTERNOON. SHORT-RANGE EXPLICIT MODELS SUCH AS THE HRRR... AND
NCEP 4KM WRF FIRE UP CONVECTION SOUTH OF THE STL METRO AREA ACROSS
THE EASTERN OZARKS WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED ALONG A
PRE-FRONTAL TROF. WHILE THE RAP AND NAM DO HAVE SOME PRECIP AS FAR
NORTH AS THE I-70 CORRIDOR...I THINK ANY PRECIP THAT BREAKS OUT THAT
FAR NORTH WILL BE SPOTTY AND WEAK. PRECIP ACROSS THE OZARKS SHOULD
END BY LATE EVENING.
(FRIDAY-SATURDAY)
SOMEWHAT COOLER AIR WILL FILTER INTO EASTERN MISSOURI AND SOUTHERN
ILLINOIS FOR FRIDAY AND SATURDAY. MODELS ARE IN GOOD AGREEMENT THAT
850MB TEMPS WILL DROP DOWN TO THE 20-22C RANGE WHICH MIXES DOWN TO
THE LOW TO MID 90S. HAVE BASICALLY IGNORED THE COOL GFS GUIDANCE
AND STUCK VERY CLOSE TO PERSISTENCE AND THE NAM. SHOULD BE ABLE TO
KEEP HEAT INDEX VALUES BELOW 100 DEGREES BOTH DAYS...SO WILL LET THE
ADVISORY EXPIRE AS PLANNED.
CARNEY
&&
.LONG TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(SUNDAY-THURSDAY)
MEDIUM RANGE GUIDANCE HAS BEEN VERY PERSISTENT IN BUILDING THE UPPER
LEVEL RIDGE BACK OVER THE AREA ON SUNDAY AND KEEPING IT OVER US
THROUGH MID-WEEK. 850MB TEMPS ON THE ECMWF RISE TO 24C-26C OVER THE
AREA AS THE THERMAL RIDGE BUILDS BACK OVER THE MIDWEST WITH A
VENGEANCE. EXPECT TEMPERATURES AOA 100 DEGREES FOR THE ENTIRE WEEK
WITH HEAT INDEX VALUES IN EXCESS OF 105. HEAT INDEX VALUES MAY BE A
BIT LOWER OVER THE EASTERN OZARKS DUE TO SLIGHTLY LOWER AMBIENT
TEMPERATURES AND LOWER DEWPOINTS SINCE THEY WILL BE FURTHEST FROM
THE THERMAL RIDGE AXIS. HAVE ISSUED AN EXCESSIVE HEAT WATCH FOR
MOST OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...BUT LEFT THE
EASTERN OZARKS OUT. MODELS TRY TO PRINT OUT SOME SPOTTY PRECIP HERE
AND THERE DURING THE AFTERNOON...BUT HAVE KEPT THE EXTENDED DRY DUE
TO THE PERSISTENT DROUGHT.
CARNEY
&&
.AVIATION...
ISSUED AT 1120 PM CDT THU JUL 19 2012
ISOLD -TSRA HAVE NOW MOVED WELL SOUTH OF THE ST. METRO TAF SITES.
NEXT CONCERN IS THE AREA OF CLOUDS WITH MVFR CIGS MOVING SOUTH INTO
CENTRAL ILLINOIS. CIG OF BKN041 HAS JUST MOVED INTO KUIN IN A PATCH
OF CLOUDS AHEAD OF THE MAIN BODY. HAVE ADDED A HIGH MVFR CIG AT
KUIN AROUND 09Z TO ACCOUNT FOR THE LOWER CIGS...BUT NOT SURE THAT
THEY WILL MAKE IT ALL THE WAY SOUTH TO THE ST. METRO TAF SITES.
HAVE ADDED SCT030 AT THE SITES STARTING 11-12Z TO ACCOUNT FOR THIS
POSSIBILITY. THEN MIXING SHOULD CAUSE ANY CLOUDS TO GO SCT BY MID
MORNING. OTHERWISE EXPECT DRY AND VFR CONDITIONS WITH NORTHERLY
WINDS SHIFT EASTERLY AFTER 00Z.
SPECIFICS FOR KSTL...THERE IS SOME SMALL CHANCE FOR MVFR CIGS TO
MOVE INTO KSTL FROM THE NORTH AROUND 12Z...BUT DO NOT HAVE HIGH
ENOUGH CONFIDENCE TO GO WITH ANY MORE THAN SCT AT THIS POINT. WILL
KEEP WITH A DRY AND VFR FORECAST AT THIS POINT WITH NORTHERLY
WINDS SHIFTING FROM THE EAST AFTER 00Z.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-
FRANKLIN MO-GASCONADE MO-JEFFERSON MO-KNOX MO-LEWIS MO-
LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST.
LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR ADAMS IL-BOND IL-BROWN IL-CALHOUN IL-CLINTON IL-
FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MARION IL-MONROE IL-MONTGOMERY IL-PIKE IL-ST. CLAIR IL-
WASHINGTON IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
344 AM MDT FRI JUL 20 2012
.SHORT TERM...VALID FOR TDY AND SAT...
IT WILL REMAIN HOT THE NEXT TWO DAYS...BUT AT LEAST SLIGHT CHANCES
OF THUNDER ARE BEING THROWN BACK INTO THE MIX TOO THANKS TO ENERGY
DAMPENING THE HOT DOME OF HIGH PRESSURE ALOFT. THE 00 UTC GUIDANCE
IS IN GOOD AGREEMENT ON THIS IDEA...AND IT LINES UP WELL WITH MOST
OF THE GOING FORECAST...SO CONTINUITY RULED WITH THIS RELEASE.
THIS MORNING...MID- AND UPPER-LEVEL MOISTURE ADVECTION AND A 55 KT
250-HPA JET STREAK MOVING INTO CENTRAL MT MAY GENERATE SOME SHOWER
ACTIVITY ACROSS THE AREA. THE LAST FEW HRRR RUNS APPEAR TOO ROBUST
WITH THIS ACTIVITY SINCE THE BOUNDARY LAYER IS STILL RATHER DRY...
BUT RADAR IMAGERY AT 09 UTC SUGGESTS SLIGHT CHANCE POPS ARE NEEDED
EVEN FOR THE BILLINGS AREA.
THIS AFTERNOON AND EVENING...LOW CHANCES OF STORMS WILL EXIST OVER
THE WHOLE AREA AS LOW-LEVEL EASTERLY FLOW BECOMES ESTABLISHED. THE
00 UTC DETERMINISTIC MODELS ALL SUGGEST THAT MID-LEVEL LAPSE RATES
WILL ACTUALLY WEAKEN BY 18 UTC THOUGH...PERHAPS IN RESPONSE TO THE
SIMULATED MOISTURE ADVECTION AND EARLY-DAY SHOWER ACTIVITY. THE 21
UTC SREF ALSO SUPPORTS THIS NOTION...SO IT IS HARD TO DISCOUNT. IT
THUS APPEARS MLCAPE WILL BE LIMITED TO LESS THAN 1000 J/KG...WHICH
MAY LIMIT STORM COVERAGE AND INTENSITY. ISOLATED SEVERE STORMS ARE
STILL POSSIBLE IN SOUTHEASTERN MT THOUGH...WHERE PROBABILITIES FOR
STORM INITIATION WILL BE HIGHER IN CLOSE PROXIMITY TO A WEAK FRONT
AND HIGHER TERRAIN OVER NORTHEASTERN WY AND WESTERN SD...AND WHERE
0-6 KM BULK WIND SHEAR OF 40 TO 50 KT IS EXPECTED.
TONIGHT...A 35 KT 850-HPA LOW-LEVEL JET IS EXPECTED TO FORM ACROSS
SOUTHEASTERN MT...WHICH SHOULD PROVIDE FORCING FOR CONVECTION ATOP
A RETREATING MID-LEVEL FRONT. MUCAPE WILL BE ON THE ORDER OF 1000
J/KG BASED ON A NON-NAM CONSENSUS...SO SOME ORGANIZED UPDRAFTS MAY
OCCUR WELL AFTER SUNSET. THE SCENARIO IS WORTHY OF SOME 40 PERCENT
TYPE OF POPS IN CARTER AND FALLON COUNTIES THROUGH THE NIGHT. EVEN
SO...THE 00 UTC GFS AND NAM BOTH SHOW SOME WEAK 500-HPA SHORT WAVE
RIDGING OVER SOUTHEASTERN MT BEFORE 12 UTC...WHICH COULD SHUT DOWN
CONVECTION EARLIER THAN EXPECTED. THE 00 UTC 4 KM WRF NMM DOES NOT
HAVE ANYTHING TO DO WITH THAT POSSIBILITY THOUGH...AS IT CALLS FOR
RATHER ROBUST CONVECTION IN FAR SOUTHEASTERN MT ALL NIGHT.
ON SAT...A WEAK FRONT IS EXPECTED TO MOVE INTO EASTERN MT...BUT IT
LOOKS LIKE MIXING BEHIND THAT FEATURE WILL EXTEND TO 650 HPA. HIGH
TEMPERATURES WILL THUS EASILY EXCEED 95 F FOR MOST LOWER ELEVATION
LOCATIONS. MLCAPE IS EXPECTED TO EXCEED 2000 J/KG EAST OF THE WIND
SHIFT WITH THAT FRONT...WHICH COULD LINGER OVER SOUTHEASTERN MT...
SO SOME POPS FOR STORMS ARE AGAIN WARRANTED IN THAT AREA. NON-ZERO
SEVERE WEATHER PROBABILITIES WILL ALSO EXIST...BUT 00 UTC GUIDANCE
SUGGESTS 0-6 KM BULK SHEAR ONLY NEAR 30 KT...WHICH MAY BE MARGINAL
FOR MORE THAN A TRANSIENT RISK WITH ANY STORMS THAT FORM. SCHULTZ
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
CRITICAL FIRE WEATHER CONDITIONS EARLY NEXT WEEK CONTINUE TO BE
THE PRIMARY CONCERN FOR THE EXTENDED PERIOD. SOUTHWEST UPPER FLOW
CONTINUES INTO MONDAY BETWEEN HIGH PRESSURE ACROSS THE PLAINS AND
APPROACHING UPPER LOW IN THE PACIFIC NORTHWEST. DISTURBANCES IN
THE FLOW WILL BE ENOUGH FOR A MENTION OF ISOLATED STORMS INTO
MONDAY. PACIFIC NORTHWEST UPPER LOW EXPECTED TO TRACK OFF TO OUR
NORTH TUESDAY THROUGH WEDNESDAY WITH ASSOCIATED COLD FRONTAL
PASSAGE ON TUESDAY. MONDAY SHOULD BE THE WARMEST DAY OF NEXT WEEK
IN A PREFRONTAL ENVIRONMENT. BUMPED TEMPERATURES UP JUST A BIT
MORE FOR MONDAY. BRISK SOUTHEAST WINDS OVER EASTERN MONTANA ARE
EXPECTED AHEAD OF THE FRONT WITH GUSTY WEST WINDS BEHIND IT
LEADING TO THE POTENTIAL FOR DANGEROUS FIRE WEATHER.
MIDWEEK WILL SEE A RELATIVE COOL DOWN WITH GRADUAL WARMING AGAIN
LATE IN THE WORK WEEK. RAISED TEMPS A BIT FOR THURSDAY AND FRIDAY
NEXT WEEK BASED ON GFS AND ECMWF PROGGED THERMAL RIDGE. ECMWF
HINTS AT A STRONGER WAVE OUT OF THE SOUTHWEST NEXT SATURDAY AS
DOES THE GFS TO A LESSER EXTENT. THIS REPRESENTS THE BEST CHANCE
OF DECENT WIDESPREAD RAINFALL ON OUR HORIZON. BT
&&
.AVIATION...
WIDELY SCATTERED SHOWERS WILL SPREAD OVER THE KLVM AREA EARLY THIS
MORNING AS WELL AS THE NEARBY MOUNTAINS....BUT CONDITIONS SHOULD
REMAIN VFR DUE TO HIGH BASES. A FEW TSTMS ARE POSSIBLE ACROSS THE
ENTIRE AREA FRIDAY AFTER 18UTC. THESE WILL BE HIGH BASED AND THUS
VFR WILL PREVAIL...THOUGH LOCAL MVFR IS A POSSIBILITY NEAR EITHER
KMLS OR KBHK. IN ADDITION...ERRATIC WIND GUSTS CAN BE EXPECTED
NEAR ANY STORMS THAT DEVELOP THIS AFTERNOON AND EVENING. BT
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SAT SUN MON TUE WED THU
-------------------------------------------------------
BIL 095 066/096 064/096 066/099 064/092 061/092 061/095
2/T 21/U 11/U 22/T 20/U 00/U 00/U
LVM 095 054/095 054/094 055/096 054/090 054/091 052/093
2/T 22/T 22/T 22/T 20/B 01/U 11/U
HDN 098 062/097 061/098 067/101 065/096 061/095 062/098
2/T 21/U 11/U 22/T 20/U 11/U 00/U
MLS 097 070/100 069/099 070/104 069/095 064/093 064/098
2/T 21/U 11/U 22/T 30/B 11/U 10/U
4BQ 097 064/099 064/098 067/100 068/094 061/093 063/098
3/T 32/T 21/B 22/T 21/U 11/U 10/U
BHK 096 064/097 065/096 066/097 067/092 064/089 061/094
2/T 42/T 31/B 22/T 32/T 22/T 10/U
SHR 095 060/096 059/096 061/098 062/093 058/093 057/096
3/T 21/B 21/B 21/B 20/B 11/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
812 PM EDT SAT JUL 21 2012
.SYNOPSIS...
HIGH PRESSURE WILL SLIDE EASTWARD ACROSS NEW ENGLAND THROUGH
SUNDAY...BRINGING WARMER TEMPERATURES AND PERHAPS A STRAY
THUNDERSTORM TO INLAND LOCATIONS. VERY WARM TEMPERATURES WILL LAST
THROUGH MONDAY...THEN A COLD FRONT WILL CROSS LATE MONDAY WITH SOME
THUNDERSTORMS. DRY WEATHER AND NEAR AVERAGE TEMPERATURES WILL THEN
RETURN FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 545 PM...SKIES ARE LARGELY MOSTLY SUNNY ACROSS THE AREA...THANKS
TO A COMBINATION OF STABILIZING LAKE BREEZES AND FLATTENING/THINNING
DIURNAL CU. JUST A SMALL AMOUNT OF LOW STRATUS LINGERS NEAR THE
NY/PA BORDER IN CATTARAUGUS COUNTY...AND EVEN THIS SHOULD
DISSIPATE IN THE NEXT HOUR WITH CONTINUED MIXING.
THIS EVENING...A WEAK UPPER TROF WILL APPROACH FROM THE UPPER LAKES.
A CONSENSUS OF THE NAM/RGEM/GFS SHOW BARELY MEASURABLE QPF WITH
THIS...AND THIS APPEARS TO BE A REASONABLE FORECAST WITH JUST A
FEW SHOWERS NOTED UPSTREAM ACROSS THE CENTRAL/UPPER LAKES AND
NEARBY SOUTHERN ONTARIO...THE CLOSEST OF WHICH IS NOW FALLING
APART AS IT WORKS INTO THE MORE STABLE AIR FROM LAKE ONTARIO.
THE HRRR BRINGS SOME SCATTERED SHOWERS INTO WESTERN NEW YORK LATE
THIS EVENING...BUT CONSIDERING THAT IT WAS OVERDONE THIS
AFTERNOON /WHEN IT ALSO TRIED TO DEVELOP SHOWERS/ WILL ONLY CARRY
A SLIGHT CHANCE OF SHOWERS WITH THIS WEAK UPPER LEVEL DISTURBANCE.
EVEN IF THIS FEATURE DOES NOT BRING SHOWERS...IT DOES APPEAR LIKELY
THAT MID-LEVEL CLOUDS ASSOCIATED WITH THIS DISTURBANCE WILL MOVE
ACROSS WESTERN NEW YORK OVERNIGHT. THIS COMBINED WITH A SSW FLOW
WILL KEEP TEMPERATURES A BIT WARMER THAN LAST NIGHT...WITH LOWS
LIKELY TO BE IN THE UPPER 60S NEAR THE LAKES...AND IN THE UPPER 50
TO LOWER 60S INLAND. IT ALSO WILL LIMIT THE POTENTIAL FOR
FOG...THOUGH ANY PROLONGED CLEARING COULD ALLOW FOR FOG TO DEVELOP.
WHILE NO DISTINCT FEATURE IS EXPECTED TO CROSS ON SUNDAY...THE
REGION WILL REMAIN UNDER THE INFLUENCE OF VERY WEAK UPPER LEVEL
TROUGHING. MEANWHILE...A SOUTHWESTERLY FLOW WILL
INCREASE...ENHANCING LAKE BREEZES NORTHEAST OF THE LAKES. THE NAM/GFS
ARE A BIT MORE AGGRESSIVE THAN THE RGEM...WITH BOTH THE
UKMET/EUROPEAN SHOWING LIGHT BUT MEASURABLE QPF ACROSS PARTS OF
WESTERN NEW YORK. WITH A STRONG LAKE-BREEZE LIKELY TO BE IN
PLACE...IT WOULD BE DIFFICULT FOR ANY SHOWERS TO DEVELOP FROM
BUFFALO TO ROCHESTER NORTHWARD...WITH THIS AREA LIKELY TO BE SHADOWED. THE
BEST CHANCE FOR SHOWERS AND THUNDERSTORMS TO DEVELOP WILL BE ALONG
THE LAKE ERIE BREEZE ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER ON
SUNDAY AFTERNOON. THERE WILL BE MODEST LEVELS OF INSTABILITY IN
PLACE GENERALLY IN THE 500 TO 1000 J/KG LEVEL. WHILE THE LACK OF
STRONG FORCING ALOFT WILL LIMIT THE EXTENT OF STORMS...THE LAKE
BREEZE MAY PROVIDE ENOUGH OF A FOCUS FOR SOME SHOWERS AND
THUNDERSTORMS TO DEVELOP.
OTHERWISE...EXPECT A FAIRLY BRISK LAKE BREEZE OFF LAKE ERIE...WITH
BUFFALO LIKELY TO GUST TO 25 MPH OR SO DURING THE AFTERNOON HOURS.
THIS SHOULD LIMIT HIGH TEMPERATURES IN BUFFALO METRO TO THE LOWER
AND MID 80S...WITH UPPER 80S LIKELY IN MORE INTERIOR SECTIONS WHICH
ARE LESS INFLUENCED BY A SW FLOW.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
THE NEXT SYSTEM OF INTEREST IS CURRENTLY NEARING SASKATCHEWAN. THIS
FAIRLY COMPACT FEATURE WILL TRACK EASTWARD ACROSS THE CANADIAN
PROVINCES AND THEN SOUTHEASTWARD TOWARD THE GREAT LAKES REGION AS
THE FEATURE TO ITS NORTH...CURRENTLY OVER THE NORTHWEST
TERRITORIES...BEGINS TO CARVE OUT A LONGWAVE TROUGH OVER THE EASTERN
HALF OF CANADA EARLY NEXT WEEK.
ON SUNDAY NIGHT...THERE WILL BE SOME ELEVATED INSTABILITY AHEAD OF
THE ABOVE MENTIONED FEATURE. THAT...TOGETHER WITH THE WARM
LAKES...MAY BE ABLE TO GENERATE SOME CONVECTION IN THE WEE HOURS OF
THE MORNING. THIS WILL BE AHEAD OF A COLD FRONT THAT IS EXPECTED TO
DROP INTO THE REGION LATER MONDAY OR MONDAY NIGHT. SUCH NOCTURNAL
EVENTS ARE ALWAYS TRICKY TO FORECAST AND RARELY HANDLED WELL BY
MODEL GUIDANCE. WILL LEAN TOWARD SREF AND CLIMO FOR THIS PERIOD.
INSTABILITY ONLY INCREASES ON MONDAY...WITH POSSIBLE ONGOING OR
PREFRONTAL CONVECTION/LAKE BREEZE DEVELOPMENT BY AFTERNOON. THE
FRONT ITSELF IS NOT CURRENTLY FORECAST TO MOVE IN UNTIL MONDAY
NIGHT. HOWEVER...SREF DATA HAS BEEN HINTING AT A POSSIBLE SEVERE
WEATHER SCENARIO WITH AMPLE 40KT WIND SHEAR AND INSTABILITY BY
AFTERNOON. SPC HAS THE REGION IN A DAY 3 OUTLOOK /SEE TEXT AREA/
AND AGREE THERE IS POTENTIAL. HOWEVER FOR NOW WILL ONLY DISCUSS THIS
AS A LOW PROB SCENARIO HERE AND NOT UPDATE THE HWO UNTIL MORE
CONFIDENCE IS SEEN IN MODEL GUIDANCE. CURRENT GUIDANCE SHOWS THAT
CONVECTION AND BEST SHEAR MAY NOT MAKE IT TO OUR REGION UNTIL PAST
PEAK HEATING...ARRIVING TOWARD MONDAY EVENING. ALSO...WINDS WILL BE
INCREASING ON MONDAY...WITH GUSTS 25-35 MPH POSSIBLE EAST OF LAKE
ERIE BY AFTERNOON...LESS SO EAST OF LAKE ONTARIO. THIS TYPE OF WIND
CAN PLAY HAVOC WITH CONVECTIVE DEVELOPMENT WITH TOO MUCH LOW LEVEL
SHEAR HINDERING CONVECTIVE INITIATION. A LOW CONFIDENCE FORECAST IS
IN PLACE FOR SUNDAY NIGHT THROUGH MONDAY NIGHT WITH RESPECT TO
CONVECTIVE TIMING...PROBABILITY AND/OR AREAL COVERAGE OF
OCCURRENCE...AND SEVERE WEATHER POSSIBILITIES ON MONDAY/MONDAY
NIGHT. THERE WILL BE SLIGHTLY HIGHER CONFIDENCE FOR CONVECTION IN
THE SOUTHERN TIER AND FINGER LAKES REGION WHICH WOULD BE THE MOST
LIKELY PLACE FOR AFTERNOON AND/OR EVENING CONVECTION BASED ON
CURRENT MODEL GUIDANCE.
CONFIDENCE INCREASES LATER TUESDAY AS THE FRONT MOVES EAST OF THE
REGION. HIGH PRESSURE IS STILL SITUATED UPSTREAM...BUT A DRYING
AIRMASS ALOFT SUGGESTS KEEPING MEASURABLE PRECIPITATION POTENTIAL
OUT OF THE FORECAST.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
HIGH PRESSURE WEDNESDAY. HIGH CONFIDENCE. THURSDAY ALSO LOOKS
LIKE A LOCK WITH WITH HIGH PRESSURE OVERHEAD.
FRIDAY AND SATURDAY HOWEVER POSE A PROBLEM. THE LATEST GFS ONCE
AGAIN SPORTS A DEEPENING LOW AS IT MOVES ACROSS THE NORTHERN GREAT
LAKES REGION...SOMETHING SIMILAR TO A FEW DAYS AGO ALTHOUGH
SLOWER...WHILE THE ECMWF HAS A TOTALLY DIFFERENT SOLUTION. WITH
SUCH UNCERTAINTY A WEEK OUT...WILL FORECAST CLIMO FOR THIS PERIOD
AND THEREFORE MENTION A CHANCE OF SHOWERS AND THUNDERSTORMS AS THERE
IS NO POINT IN TRYING TO PIN DOWN FEATURES WHICH ARE IN MODEL
FANTASY LAND AND NOT TRACKABLE.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...LOTS OF MID LEVEL CLOUDS STREAMING INTO THE CWA IN
ASSOCIATED WITH A WEAK UPPER TROUGH MOVING ACROSS THE GREAT LAKES
REGION THIS EVENING. REGIONAL RADARS SHOW LITTLE IN THE WAY OF
MOISTURE WITH THIS SYSTEM...A FEW ISOLATED SHOWERS AND THUNDERSTORMS
FAR UPSTREAM OVER MICHIGAN...NO IMPACT TO LOCAL AVIATION
OPERATIONS. CLOUD DEBRIS FROM THIS SYSTEM SHOULD KEEP TEMPERATURES
UP A BIT FROM LAST NIGHT...WHICH SHOULD ELIMINATE MOST IF NOT ALL
FOG FORMATION ALLOWING VFR CONDITIONS TO PREVAIL OVERNIGHT.
A WEAK DISTURBANCE WILL PASS ON SUNDAY...RESULTING IN A LOW CHANCE
OF SHOWERS. COVERAGE SHOULD BE QUITE SPARSE...AND SHOWERS ARE NOT
LIKELY TO HAVE AN IMPACT ON TAF LOCATIONS. THE ONLY OTHER AREA
OF CONCERN WILL BE SW FLOW OFF OF LAKE ERIE WITH KBUF LIKELY
SEEING GUSTS UP TO 25 KTS DURING THE AFTERNOON HOURS.
OUTLOOK...
SUNDAY NIGHT...MAINLY VFR.
MONDAY AND MONDAY NIGHT...MAINLY VFR WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS.
TUESDAY THROUGH THURSDAY...VFR.
&&
.MARINE...
WINDS WILL REMAIN ON THE LIGHT SIDE OVERNIGHT...AS A SOUTHWESTERLY
FLOW GAINS INFLUENCE OVER LINGER LAKE BREEZE AFFECTS. SOUTHWEST
WINDS WILL INCREASE ON THE LAKES SUNDAY...BUT FLOW WILL LIKELY
REMAIN BELOW SMALL CRAFT CRITERIA...THOUGH WINDS MAY BUILD WAVES ON
LAKE ERIE SUNDAY AFTERNOON.
THE FRONT WILL CROSS THE WATERS MONDAY NIGHT...WITH AN INCREASING
SOUTHWEST FLOW ON MONDAY. SMALL CRAFT ADVISORIES MAY BE NEEDED AHEAD
OF THIS FRONT. AFTER THIS...HIGH PRESSURE WILL GRADUALLY BUILD
ACROSS THE WATERS...WITH GENERALLY LIGHT WINDS THROUGH MID-WEEK.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/JJR
SHORT TERM...ZAFF
LONG TERM...ZAFF
AVIATION...AR/APFFEL
MARINE...APFFEL/ZAFF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1020 PM EDT SAT JUL 21 2012
.SYNOPSIS...
TYPICAL SUMMER TIME WEATHER WILL CONTINUE WITH BERMUDA HIGH PRESSURE
OFFSHORE AND SURFACE LOW PRESSURE INLAND PRODUCING SOUTHWEST WINDS
AND LOCALIZED THUNDERSTORMS TO THE COASTAL CAROLINAS. A BUILDING
RIDGE ALOFT WILL BRING A WARMING TREND THROUGH NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 PM SATURDAY...LATEST SFC ANALYSIS PLACES THE STATIONARY
FRONT JUST NORTH OF THE AREA...EXTENDING FROM ROUGHLY DUCK NC
WEST-SOUTHWEST TO NASHVILLE NC. THIS KEEPS THE FA WITHIN THE JUICY
AIR MASS PAINTED WITH PWS OF 2+ INCHES. THE MAJORITY OF THE DAYS
CONVECTION HAS WANED ACROSS THE AREA AND WAS LIKELY A PRODUCT FROM
SFC FORCING...IE. SEA BREEZE AND RESIDUAL OUTFLOW BOUNDARIES.
MID-LEVEL TROFFINESS WILL PERSIST TONIGHT INTO SUNDAY. A WEAK
IMPULSE EMBEDDED IN 5H FLOW IS PROGGED TO MOVE FROM GSP THIS EVENING
ACROSS PORTIONS OF THE FA OVERNIGHT TO THE SOUTHERN OUTER BANKS
AFTER SUNDAYS SUNRISE. THE DYNAMICS FROM THE IMPULSE WILL BE ENOUGH
TO IGNITE ISOLATED/WIDELY SCATTERED TSRA DURING A PORTION OF THE
OVERNIGHT. AND FOR THAT REASON HAVE KEPT AN ACTIVE OVERNIGHT POP
ACROSS THE NORTHERN PORTIONS OF THE FA THROUGH THE MID TO LATE
EVENING HRS. ANOTHER WARM AND STICKY NIGHT ON TAP FOR THE FA...WITH
LOW TEMPS RANGING FROM THE MID 70S INLAND TO THE UPPER 70S TO AROUND
80 ALONG THE IMMEDIATE COAST. THE SFC PG IS NOT AS PRONOUNCED LIKE
PREVIOUS NIGHTS. THIS WILL RESULT IN SW WINDS 5 MPH OR LESS
INLAND...5 TO 15 MPH ALONG THE IMMEDIATE COAST. THE UPPER RANGE
LIMIT WILL OCCUR THIS EVENING DUE TO THE DECAY OF AN ACTIVE SEA
BREEZE CIRCULATION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...BERMUDA HIGH AND PIEDMONT TROUGH REMAIN TWO
DOMINANT SURFACE FEATURES CONTROLLING COASTAL CAROLINAS WEATHER.
THIS WILL MAINTAIN A SW SFC FLOW VEERING AROUND TO MORE WESTERLY
THROUGH THE LOW TO MID LEVELS. 850 TO 700 MB WINDS WILL BE 15 TO
25 KTS SUN AFTN INCREASING UP TO 20 TO 30 KTS MON AFTN AS THEY
VEER TOWARD THE NW. MID TO UPPER TROUGH LIFTS OFF TO THE NORTH
NORTHEAST AS RIDGE BUILDS IN FROM EAST AND WEST EXPANDING ACROSS
THE SOUTHEAST SUNDAY THROUGH MONDAY. ANY SHORTWAVE ENERGY TOPPING
THE RIDGE SHOULD REMAIN JUST TO NORTH OF LOCAL CWA. H5 HEIGHTS WILL
RISE UP TO 595 DEM AND WILL SEE INCREASED BUT WEAKER SUBSIDENCE
AND DRIER AIR THROUGH THE MID LEVELS. WITH BEST UPPER LEVEL SUPPORT
TO THE NORTH AND STRONG WESTERLY LOW TO MID LEVEL FLOW...EXPECT
MORE LOCALIZED CONVECTION ALONG CONVERGENT BOUNDARIES TYPICAL OF
SUMMERTIME...WITH BETTER CHC OVER NC. SEA BREEZE SHOULD REMAIN FAIRLY
CLOSE TO THE COAST WITH STRONGER WESTERLY COMPONENT TO
FLOW...ESPECIALLY ON MONDAY. THEREFORE ANY CONVECTION THAT FORMS
ALONG SEA BREEZE BOUNDARY WILL BE CLOSER TO THE COAST AND WILL
MOVE RAPIDLY OFF TO THE EAST TOWARD THE WATERS. ALSO EXPECT OTHER
SHWRS/TSTMS TO DEVELOP ALONG PIEDMONT TROUGH FURTHER INLAND AND
MOVE EAST TOWARD THE COAST. MOISTURE PROFILES DO SHOW VERY MOIST
UPPER LEVELS WITH WINDS ABOVE H4 HAVING GOOD NW-N COMPONENT.
THEREFORE EXPECT PERIODS OF CIRRUS...MAINLY FROM CONVECTIVE DEBRIS
CLOUDS FROM CONVECTION UPSTREAM. THIS SHOULD FILTER OUT SOME OF
THE SUN.
WITH RISING H5 HEIGHTS AND STRONG LOW LEVEL WESTERLY COMPONENT TO
THE FLOW...EXPECT WARM SUMMERTIME TEMPS RUNNING BETWEEN 90 AND 95
MOST PLACES.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...A RETURN TO HOT AND HUMID WEATHER EXPECTED
FOR MUCH OF THE EXTENDED...WITH ABOVE CLIMO PRECIP CHANCES THROUGH
LATE WEEK.
LARGE ELONGATED UPPER RIDGE EXTENDING FROM NEBRASKA SOUTHEAST INTO
FLORIDA WILL GET GRADUALLY PUSHED SOUTHWARD AS A LARGE UPPER LOW
ACROSS CANADA SHEARS OFF AND DROPS VORT IMPULSES INTO A BROAD
EASTERN LONGWAVE TROUGH. AS THIS OCCURS...W/NW FLOW DEVELOPS THROUGH
MUCH OF THE COLUMN ABOVE THE IMMEDIATE SURFACE. AT THE
SURFACE...LARGE BERMUDA HIGH PRESSURE GETS SHUNTED SOUTH AS
WELL...BUT NEAR SURFACE S/SW FLOW PERSISTS THROUGH THE PERIOD.
THE COMBINATION OF THE MID LEVEL TROUGH...850MB TEMPS AROUND
20C...AND MOIST RETURN SURFACE FLOW WILL CREATE DECENT CONVECTION
CHANCES EACH DAY...WITH WIDESPREAD COVERAGE POSSIBLE ESPECIALLY ON
WEDNESDAY. AN ACTIVE PIEDMONT TROUGH AND SEA BREEZE FRONT WILL OCCUR
EACH DAY...ALTHOUGH WITH THE DEEP W/NW FLOW THE SEA BREEZE WILL
REMAIN PINNED NEAR THE COAST. PWATS OF TWO INCHES OR GREATER AND
HIGH THETA-E AIR COMBINED WITH STEEP LOW LEVEL LAPSE RATES AND
SUBTLE VORT IMPULSES WILL SPAWN CONVECTION EACH AFTN...BUT MOST
ACTIVITY WILL BE DIURNALLY FORCED AND WILL KEEP INHERITED
CHC-BY-DAY...SILENT-BY-NIGHT POP. THE BEST TSTM COVERAGE WILL BE
WEDNESDAY AHEAD OF A COLD FRONT WHICH WILL TRY TO DROP SOUTH INTO
THE ILM CWA. EXPECT THIS BOUNDARY TO GET HUNG UP JUST NORTH OF THE
AREA...BUT THIS WILL STILL SERVE AS AN ADDITIONAL FOCUS FOR
CONVECTION DURING WED/WED NIGHT. OVERALL POP WILL TREND DOWNWARD
LATE IN THE PERIOD AS 500MB RIDGE BUILDS BACK TO THE NORTH.
HOWEVER...WILL KEEP SCHC POP (SILENT BY DAY 6/7) FOR ISOLATED TSTMS
IN A STILL VERY WARM/MOIST AIR MASS.
850MB TEMPS AROUND 20C WILL SUPPORT HIGHS WELL INTO THE 90S MOST
DAYS EVEN WITH THE LIMITING IMPACT OF CLOUD COVER. MINS AT NIGHT
WILL FALL ONLY INTO THE MID 70S...NEAR 80 SOME NIGHTS AT THE COAST.
&&
.AVIATION /00Z SATURDAY THROUGH THURSDAY/...
AS OF 00Z...CONVECTION IS REALLY WANING AT THIS POINT...WITH MAINLY
VCSH ADVERTISED IN THE TAFS. THE HRRR MODEL DOES DEPICT ANOTHER
BATCH OF CONVECTION AROUND 05Z...MOVING INTO THE NORTHWEST PORTION
OF THE CWA. THIS FEATURE PROBABLY HAS BEEN OVERDONE...AND THE LATEST
HOURLY RUN DOES WEAKEN IT A BIT.
MOSTLY MID AND HIGH CLOUD CONVECTIVE DEBRIS WILL BE THE RULE
OVERNIGHT...AREAS THAT RECEIVED DECENT RAINFALL...MAINLY LBT...COULD
SEE SOME MVFR FOG TOWARD SUNRISE. SUNDAY...CONTINUED SOUTHWEST
FLOW...A BIT WEAKER THAN TODAY. LIKEWISE DEEP MOISTURE IS A BIT LESS
THAN TODAY...BUT STILL COULD SQUEEZE OUT ISOLATED CONVECTION TOWARD
THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...CHANCE OF AFTERNOON THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 PM SATURDAY...THE DECAYING SEA BREEZE WILL RESULT IN
SSW-SW WINDS 15 TO OCCASIONALLY 20 KT THROUGH THIS MID-EVENING HRS
...BEFORE FINALLY BACKING DOWN TO SW 10 TO 15 KT DURING THE
PRE-DAWN HRS OF SUNDAY. THE SFC PG WILL NOT BE NEARLY AS TIGHT LIKE
THE PREVIOUS FEW DAYS...AND THE NOCTURNAL 925MB JET IS NOT AS
PRONOUNCED LIKE THE PREVIOUS FEW DAYS. THUS...THE REASONS FOR THE
LOWER FORECAST WIND SPEEDS FOR THE OVERNIGHT INTO SUNDAY. SIG SEAS
WILL RUN 2 TO 4 FT AND BE RULED BY THE 5 TO 6 SECOND SHORT PERIOD
LOCALLY PRODUCED WIND DRIVEN WAVES. WAVEWATCH3 ILLUSTRATES AN
INCREASE OF THE 9-10 SECOND PERIOD ESE GROUND SWELL FROM 1/2 FT THIS
EVENING TO 1+ FT BY SUNRISE SUNDAY. THIS WILL OFFSET THE SUBSIDING
WIND DRIVEN WAVE HEIGHTS AS A RESULT OF THE DIMINISHING WIND FIELD.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...SOUTHWEST FLOW WILL CONTINUE BETWEEN
BERMUDA HIGH TO THE EAST AND PIEDMONT TROUGH OVER INLAND
CAROLINAS. NAM SHOWING DECENT LOW LEVEL JETTING BOTH SUN AND MON
NIGHT BUT STRONGER MON NIGHT AS WINDS ALOFT INCREASE UP TO 25 TO
30 KTS. OVERALL EXPECT SFC WINDS AROUND 15 KTS SUNDAY INCREASING
UP TO 15 TO 20 KTS ON MONDAY AND VEERING SLIGHTLY MORE TO THE
W-SW. EACH AFTERNOON WINDS WILL BECOME SLIGHTLY MORE ON SHORE AND
GUSTIER CLOSE TO THE COAST AS SEA BREEZE DEVELOPS. WNA SHOWING
LONGER PERIOD UP TO 10 SECOND SWELLS MIXING WITH LOCALLY DRIVEN
WIND WAVES TO PRODUCE SEAS 2 TO 4 FT. SHOULD REACH UP TO 4 TO 5 FT
IN OUTER WATERS MON NIGHT IN STRONGER W-SW WINDS.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...TYPICAL SUMMERTIME PATTERN THROUGH THE
EXTENDED WITH PERSISTENT SW RETURN FLOW DOMINATING THE SYNOPTIC
WIND. SW WINDS OF 15-20 KTS WILL OCCUR ON BOTH TUESDAY AND
WEDNESDAY...EASING TO AROUND 10 KTS AND VEERING TO SLIGHTLY MORE
W/SW BY THURSDAY AS A BACK DOOR TYPE FRONT APPROACHES FROM THE
NORTH. THESE SW WINDS WILL KEEP A 4-5FT/5SEC SW WIND WAVE ONGOING
THROUGH THE PERIOD...ALTHOUGH AMPLITUDE WILL DECAY SLIGHTLY ON
THURSDAY. AT THE SAME TIME...THE PERSISTENT FLOW AROUND HIGH
PRESSURE RIDGE OVER THE ATLANTIC WILL KEEP A SE GROUND SWELL PRESENT
WITHIN THE WAVE SPECTRUM. SWELL INITIALLY OF 2FT/9SEC WILL BECOME
2FT/13 SEC BY THURSDAY. SEAS OF 3-5 FT TUESDAY WILL SLOWLY
DECREASE...BECOMING 2-3 FT THURSDAY THANKS TO EASING WINDS AND THE
LONGER PERIOD SWELL DECAYING MORE QUICKLY DUE TO OCEAN BOTTOM
FRICTION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
955 PM EDT SAT JUL 21 2012
.SYNOPSIS...
A WEAK FRONT WILL HOLD NEAR THE VIRGINIA BORDER THROUGH EARLY
MONDAY. THE FRONT WILL THEN DISSIPATE AS UPPER LEVEL HIGH PRESSURE
BUILDS OVER THE LOWER MISSISSIPPI VALLEY... GULF COAST STATES... AND
SOUTHEAST THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 PM SATURDAY...
DPVA ASSOCIATED WITH AN ELONGATING SHEAR AXIS APPROACHING FROM THE
NORTHWEST AND A COUPLE SUBTLE DISTURBANCES NOTED IN WATER VAPOR
IMAGERY AND RUC 500MB ANALYSIS... ARE HELPING TO SUSTAIN CONVECTION
ALONG VARIOUS OUTFLOWS AND PRESUMABLY THE ORIGINAL WEAK COLD FRONT
NEAR THE VA BORDER EARLIER THIS AFTERNOON. THE APPROACH OF THE
UPPER LEVEL SHEAR AXIS AND MERGING COLD POOLS APPEARS TO BE HELPING
TO PUSH THE FRONT SOUTHWARD TOWARD THE US HWY 64 CORRIDOR...WHERE
ONGOING THUNDERSTORMS CURRENTLY STRETCH FROM NEAR ASHEBORO TO
RALEIGH TO THE ROCKY MOUNT AREA. WHILE MUCH OF THE CWA HAS BEEN
STABILIZED BY CONVECTION DURING THE PAST 6 HOURS...PW IS STILL
AROUND 2 INCHES AND THE SPC MESOANALYSIS SHOWS AN AXIS OF MLCAPE
EXTENDING FROM THE SOUTHERN PIEDMONT TO THE SANDHILLS....WHICH
SHOULD SUPPORT SCATTERED SHOWERS AND STORMS INTO THE OVERNIGHT
HOURS. MOST OF THE OPERATIONAL MODELS KEEP CONVECTION GOING THROUGH
12Z WHILE THE SHEAR AXIS MOVES ACROSS THE AREA...WITH MOST QPF
SHIFTING TOWARD THE COAST. THE SEVERE THREAT...WHICH HAS BEEN
LIMITED TO JUST A FEW STORMS THIS EVENING...WILL ALSO BE ON DOWNWARD
TREND AS INSTABILITY WANES. RAINFALL WAS RATHER HEAVY THIS EVENING
WITH A FEW AREAS RECEIVING 2-4 INCHES...ESPECIALLY OVER THE NORTHERN
COASTAL PLAIN...SO THERE MAY BE SOME PATCHY FOG LATE TONIGHT. THE
HRRR AND RUC RH CROSS-SECTIONS SUGGEST STRATUS WILL REDEVELOP BY
09Z...AND THERE ARE SIGNS OF STRATUS ALREADY DEVELOPING NORTH OF THE
NC/VA BORDER. LOWS SHOULD HOLD IN THE LOW TO MID 70S.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 250 PM SATURDAY...
WHILE MOISTURE REMAINS PLENTIFUL OVERALL...WITH PRECIPITABLE WATER
VALUES TO AROUND TWO INCHES PARTICULARLY ON THE NAM...THE GFS BUFR
SOUNDINGS ARE NOTICEABLY MORE STABLE PARTICULARLY WITH SLIGHT
WARMING IN THE LAYER AROUND 850MB. THE SHEAR AXIS WEAKENS AND SHOULD
PIVOT WEST AND WEAKEN IN RESPONSE TO INCREASING HEIGHTS ALOFT. WHILE
OVERALL INSTABILITY APPEARS BETTER SUNDAY AFTERNOON AS OPPOSED TO
THIS AFTERNOON...WITH MLCAPE LIKELY REACHING OR JUST EXCEEDING
2000J/KG...OVERALL COVERAGE OF SHOWERS AND THUNDERSTORMS IN CENTRAL
NORTH CAROLINA IS LIKELY TO BE LESS AS A RESULT OF WHAT SHOULD BE
DIMINISHING SYNOPTIC SUPPORT. THE FRONT SHOULD CONTINUE TO SLOWLY
WEAKEN...AND WITH THE SHEAR AXIS WEAKENING AS WELL...WILL CONTINUE
THE FORECAST OF SCATTERED SHOWERS AND THUNDERSTORMS FROM THE
AFTERNOON THROUGH THE EARLY EVENING. THERE IS STILL THE POTENTIAL
FOR AN ISOLATED DAMAGING WIND THREAT...AND AGREE WITH THE SPC DAY 2
ASSESSMENT OF THAT ISOLATED POTENTIAL. DOWNDRAFT CAPE IS 500-900J/KG
AS FORECAST BY THE MORE ROBUST NAM...UNDER A RELATIVE MAXIMUM OF
850MB THETA-E. HIGH TEMPERATURES SHOULD MOSTLY BE IN THE LOWER 90S...
WITH A FEW HIGHS POSSIBLE AROUND 90 OR TOWARD 95 DEPENDING ON HOW
QUICKLY ANY MORNING LOW CLOUDS DIMINISH...AND THE ONSET OF ANY DEEP
CONVECTION.
SUNDAY NIGHT...BOTH THE NAM AND THE GFS BUFR SOUNDINGS BECOME FAIRLY
STABLE TO DEEP CONVECTION. THE GFS DOES FORECAST SOME OVERNIGHT
QPF...BUT ITS MOS GUIDANCE CHANCES OF RAIN ARE LOW LATE AT NIGHT...
AND WITH CONVERGENCE ALOFT FORECAST OVERNIGHT SUNDAY...IT WOULD SEEM
CHANCES FOR ANY SHOWERS AND THUNDERSTORMS SHOULD FALL BELOW SLIGHT
CHANCE BY AROUND MIDNIGHT. OVERNIGHT LOWS ONCE AGAIN SHOULD BE
MOSTLY IN THE RANGE OF 70 TO 75.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
THE MAIN WEATHER FEATURE DURING MUCH OF THE LONG TERM PERIOD WILL BE
BROAD MID LEVEL RIDGING THAT IS PROGGED TO EXTEND FROM THE CENTRAL
PLAINS INTO THE SOUTHEAST...WITH CENTRAL NC ON THE NORTHERN
PERIPHERY OF THIS RIDGE. THEREFORE...WE WILL BE UNDER NORTHWESTERLY
FLOW ALOFT FOR MUCH OF THE PERIOD AND HENCE THE POTENTIAL FOR WEAK
DISTURBANCES TO IMPACT THE AREA WILL LIKELY BE OUR MAIN CHANCES FOR
ANY PRECIP BEYOND TYPICAL SUMMERTIME CONVECTION. MODELS ALSO
INDICATE (TO VARYING DEGREES) A BACK DOOR FRONT APPROACHING THE AREA
MIDWEEK...BUT GIVEN THE TIME OF YEAR...WILL KEEP THE FRONT NORTH OF
REGION FOR NOW. AS A RESULT...SINCE IT IS IMPOSSIBLE TO TIME ANY
WEAK UPPER LEVEL DISTURBANCES THIS FAR OUT...AM EXPECTING MOSTLY
ISOLATED TO SCATTERED DIURNAL TYPE PRECIP AS A WEAK SURFACE TROUGH
WILL BE IN PLACE OVER THE REGION. THEN...AT THE END OF THE WORK
WEEK...A SHORT WAVE TROUGH IS PROGGED TO AMPLIFY ACROSS THE NORTHERN
PLAINS WHICH WILL EVENTUALLY SUPPRESS THE RIDGE. AS THIS SHORT WAVE
MOVES EAST AND AMPLIFIES EVEN MORE...IT SHOULD BEGIN TO CARVE AN
UPPER LEVEL TROUGH OVER THE REGION BY THE WEEKEND...WITH AN
ASSOCIATED SURFACE FRONT APPROACHING FROM THE NORTHWEST. WILL STILL
KEEP ONLY SCATTERED DIURNAL CONVECTION IN THE FORECAST FOR THIS TIME
FRAME...BUT WILL SHOW A SLIGHT INCREASE IN THE POPS. THE HEAT WILL
ALSO RETURN TO THE REGION...WITH GENERALLY MID (AND SOME UPPER) 90S
EXPECTED FOR MOST OF THE PERIOD. OVERNIGHT LOWS WILL REMAIN IN THE
LOW TO MID 70S.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 755 PM SATURDAY...
CHALLENGING AVIATION FORECAST AS A BROKEN BAND OF SCATTERED STRONG
TO SEVERE STORMS EXTENDS ACROSS NORTHERN SECTIONS OF CENTRAL NC
EARLY THIS EVENING. BASED ON THE CURRENT MOVEMENT OF STORMS TOWARD
THE SOUTH... AND A GUST OF STRONG WINDS ALSO MOVING SOUTHWARD
RUNNING OUT AHEAD OF THE STORMS... THESE WILL REMAIN IN THE VICINITY
OF INT/GSO THROUGH 03Z... AND MAY PASS DIRECTLY OVER RDU AND RWI
PRIOR TO 04Z. BRIEF MVFR TO IFR CONDITIONS AND NORTHEAST WINDS
GUSTING TO 20-30 KTS ARE LIKELY BENEATH THESE STORMS... AND AVIATION
INTERESTS SHOULD ALSO BE ALERT FOR VERY FREQUENT LIGHTNING STRIKES.
CONFIDENCE IS HIGH THAT IFR/LIFR STRATUS BASED BELOW 1 THOUSAND FT
AGL WILL REDEVELOP TONIGHT AFTER 06Z... AND THIS IS SUPPORTED BY THE
LATEST HRRR MODEL AVIATION OUTPUT. MVFR VSBYS ARE ALSO EXPECTED. LOW
CLOUDS WILL SLOWLY LIFT TO MVFR BUT WILL LIKELY REMAIN BROKEN
THROUGH 14Z... NOT BECOMING VFR UNTIL AFTER 16Z. ADDITIONAL
SCATTERED STORMS ARE EXPECTED AFTER 18Z SUNDAY... BUT CONFIDENCE IN
THE TIMING AND LOCATION OF DEVELOPMENT PRECLUDES PLACING A
THUNDERSTORM MENTION IN THE AVIATION FORECAST AT THIS TIME.
LOOKING BEYOND EARLY SUNDAY EVENING... PATCHY IFR STRATUS AND MVFR
FOG ARE EXPECTED AT RDU/RWI/FAY LATE SUNDAY NIGHT THROUGH MONDAY
MORNING. AS A WARM AND HUMID AIR MASS HOLDS OVER THE REGION THROUGH
MID WEEK... DAILY OCCURRENCES OF AFTERNOON AND EARLY EVENING SHOWERS
AND STORMS WITH LOCALLY GUSTY WINDS AND MVFR CONDITIONS IN HEAVY
RAIN ARE POSSIBLE AT EACH TERMINAL THROUGH THURSDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...DJF/SMITH
SHORT TERM...DJF
LONG TERM...KRR
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
755 PM EDT SAT JUL 21 2012
.SYNOPSIS...
A WEAK FRONT WILL HOLD NEAR THE VIRGINIA BORDER THROUGH EARLY
MONDAY. THE FRONT WILL THEN DISSIPATE AS UPPER LEVEL HIGH PRESSURE
BUILDS OVER THE LOWER MISSISSIPPI VALLEY... GULF COAST STATES... AND
SOUTHEAST THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 250 PM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE SURFACE FRONT VERY NEAR THE
VIRGINIA BORDER...LIKELY JUST NORTH OF THE BORDER WITH KTDF STILL
SHOWING A SOUTHWEST WIND. OUTFLOW FROM ONGOING AND DEVELOPING
SHOWERS AND THUNDERSTORMS MAY RESULT IN THE FRONT SHIFTING SLIGHTLY
SOUTH ACROSS THE BORDER DURING THE EVENING AND OVERNIGHT HOURS...BUT
ITS OVERALL LOCATION SHOULD BE VERY SIMILAR TO ITS CURRENT ONE
THROUGH THE NEAR- AND SHORT-TERM PERIODS. THE SPC MESOANALYSIS
SHOWED MLCAPE FROM 1000 TO 2000J/KG...THOUGH SHEAR IS VERY WEAK AS
ANTICIPATED AND DOWNDRAFT CAPE IS FAIRLY LOW AS WELL...MOSTLY LESS
THAN 500J/KG EXCEPT IN THE FAR SOUTH TOWARD THE SOUTH CAROLINA
BORDER. 850MB LIFT ON THE SHORT-TERM GUIDANCE IS BEST THIS EVENING...
AND WHILE AN ISOLATED SEVERE THUNDERSTORM IS POSSIBLE DUE TO
DAMAGING WIND...MOST STORMS THROUGH THE AFTERNOON AND EVENING SHOULD
END UP ON THE STRONG SIDE WITH MOST OF THE GUST POTENTIAL OF 40 TO
50 MPH. AS AFTERNOON THUNDERSTORMS CONTINUE TO DEVELOP NEAR THE
FRONT AND ASSOCIATED WITH DIFFERENTIAL HEATING AND THE MID-LEVEL
SHEAR AXIS TO THE SOUTH AND SOUTHEAST...GENERAL MOVEMENT EAST AND
NORTHEAST SHOULD RESULT IN LIKELY CHANCES FOR SHOWERS AND
THUNDERSTORMS FROM THE LATE AFTERNOON THROUGH AT LEAST THE EARLY
EVENING ACROSS CENTRAL NORTH CAROLINA. DEVELOPMENT OVER THE
NORTHWEST FOOTHILLS...AGAIN NEAR THE FRONT...SHOULD EVENTUALLY
AFFECT THE TRIAD AS WELL. OVERNIGHT...BUFR SOUNDINGS BECOME MORE
STABLE ESPECIALLY ON THE GFS...ALTHOUGH WITH DECENT MOISTURE AND THE
PRESENCE OF THE SHEAR AXIS ALOFT ALONG WITH THE PROXIMITY OF THE
FRONT...WILL NOT COMPLETELY ELIMINATE CHANCES FOR A SHOWER.
OVERNIGHT LOWS...69 TO 74.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 250 PM SATURDAY...
WHILE MOISTURE REMAINS PLENTIFUL OVERALL...WITH PRECIPITABLE WATER
VALUES TO AROUND TWO INCHES PARTICULARLY ON THE NAM...THE GFS BUFR
SOUNDINGS ARE NOTICEABLY MORE STABLE PARTICULARLY WITH SLIGHT
WARMING IN THE LAYER AROUND 850MB. THE SHEAR AXIS WEAKENS AND SHOULD
PIVOT WEST AND WEAKEN IN RESPONSE TO INCREASING HEIGHTS ALOFT. WHILE
OVERALL INSTABILITY APPEARS BETTER SUNDAY AFTERNOON AS OPPOSED TO
THIS AFTERNOON...WITH MLCAPE LIKELY REACHING OR JUST EXCEEDING
2000J/KG...OVERALL COVERAGE OF SHOWERS AND THUNDERSTORMS IN CENTRAL
NORTH CAROLINA IS LIKELY TO BE LESS AS A RESULT OF WHAT SHOULD BE
DIMINISHING SYNOPTIC SUPPORT. THE FRONT SHOULD CONTINUE TO SLOWLY
WEAKEN...AND WITH THE SHEAR AXIS WEAKENING AS WELL...WILL CONTINUE
THE FORECAST OF SCATTERED SHOWERS AND THUNDERSTORMS FROM THE
AFTERNOON THROUGH THE EARLY EVENING. THERE IS STILL THE POTENTIAL
FOR AN ISOLATED DAMAGING WIND THREAT...AND AGREE WITH THE SPC DAY 2
ASSESSMENT OF THAT ISOLATED POTENTIAL. DOWNDRAFT CAPE IS 500-900J/KG
AS FORECAST BY THE MORE ROBUST NAM...UNDER A RELATIVE MAXIMUM OF
850MB THETA-E. HIGH TEMPERATURES SHOULD MOSTLY BE IN THE LOWER 90S...
WITH A FEW HIGHS POSSIBLE AROUND 90 OR TOWARD 95 DEPENDING ON HOW
QUICKLY ANY MORNING LOW CLOUDS DIMINISH...AND THE ONSET OF ANY DEEP
CONVECTION.
SUNDAY NIGHT...BOTH THE NAM AND THE GFS BUFR SOUNDINGS BECOME FAIRLY
STABLE TO DEEP CONVECTION. THE GFS DOES FORECAST SOME OVERNIGHT
QPF...BUT ITS MOS GUIDANCE CHANCES OF RAIN ARE LOW LATE AT NIGHT...
AND WITH CONVERGENCE ALOFT FORECAST OVERNIGHT SUNDAY...IT WOULD SEEM
CHANCES FOR ANY SHOWERS AND THUNDERSTORMS SHOULD FALL BELOW SLIGHT
CHANCE BY AROUND MIDNIGHT. OVERNIGHT LOWS ONCE AGAIN SHOULD BE
MOSTLY IN THE RANGE OF 70 TO 75.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
THE MAIN WEATHER FEATURE DURING MUCH OF THE LONG TERM PERIOD WILL BE
BROAD MID LEVEL RIDGING THAT IS PROGGED TO EXTEND FROM THE CENTRAL
PLAINS INTO THE SOUTHEAST...WITH CENTRAL NC ON THE NORTHERN
PERIPHERY OF THIS RIDGE. THEREFORE...WE WILL BE UNDER NORTHWESTERLY
FLOW ALOFT FOR MUCH OF THE PERIOD AND HENCE THE POTENTIAL FOR WEAK
DISTURBANCES TO IMPACT THE AREA WILL LIKELY BE OUR MAIN CHANCES FOR
ANY PRECIP BEYOND TYPICAL SUMMERTIME CONVECTION. MODELS ALSO
INDICATE (TO VARYING DEGREES) A BACK DOOR FRONT APPROACHING THE AREA
MIDWEEK...BUT GIVEN THE TIME OF YEAR...WILL KEEP THE FRONT NORTH OF
REGION FOR NOW. AS A RESULT...SINCE IT IS IMPOSSIBLE TO TIME ANY
WEAK UPPER LEVEL DISTURBANCES THIS FAR OUT...AM EXPECTING MOSTLY
ISOLATED TO SCATTERED DIURNAL TYPE PRECIP AS A WEAK SURFACE TROUGH
WILL BE IN PLACE OVER THE REGION. THEN...AT THE END OF THE WORK
WEEK...A SHORT WAVE TROUGH IS PROGGED TO AMPLIFY ACROSS THE NORTHERN
PLAINS WHICH WILL EVENTUALLY SUPPRESS THE RIDGE. AS THIS SHORT WAVE
MOVES EAST AND AMPLIFIES EVEN MORE...IT SHOULD BEGIN TO CARVE AN
UPPER LEVEL TROUGH OVER THE REGION BY THE WEEKEND...WITH AN
ASSOCIATED SURFACE FRONT APPROACHING FROM THE NORTHWEST. WILL STILL
KEEP ONLY SCATTERED DIURNAL CONVECTION IN THE FORECAST FOR THIS TIME
FRAME...BUT WILL SHOW A SLIGHT INCREASE IN THE POPS. THE HEAT WILL
ALSO RETURN TO THE REGION...WITH GENERALLY MID (AND SOME UPPER) 90S
EXPECTED FOR MOST OF THE PERIOD. OVERNIGHT LOWS WILL REMAIN IN THE
LOW TO MID 70S.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 755 PM SATURDAY...
CHALLENGING AVIATION FORECAST AS A BROKEN BAND OF SCATTERED STRONG
TO SEVERE STORMS EXTENDS ACROSS NORTHERN SECTIONS OF CENTRAL NC
EARLY THIS EVENING. BASED ON THE CURRENT MOVEMENT OF STORMS TOWARD
THE SOUTH... AND A GUST OF STRONG WINDS ALSO MOVING SOUTHWARD
RUNNING OUT AHEAD OF THE STORMS... THESE WILL REMAIN IN THE VICINITY
OF INT/GSO THROUGH 03Z... AND MAY PASS DIRECTLY OVER RDU AND RWI
PRIOR TO 04Z. BRIEF MVFR TO IFR CONDITIONS AND NORTHEAST WINDS
GUSTING TO 20-30 KTS ARE LIKELY BENEATH THESE STORMS... AND AVIATION
INTERESTS SHOULD ALSO BE ALERT FOR VERY FREQUENT LIGHTNING STRIKES.
CONFIDENCE IS HIGH THAT IFR/LIFR STRATUS BASED BELOW 1 THOUSAND FT
AGL WILL REDEVELOP TONIGHT AFTER 06Z... AND THIS IS SUPPORTED BY THE
LATEST HRRR MODEL AVIATION OUTPUT. MVFR VSBYS ARE ALSO EXPECTED. LOW
CLOUDS WILL SLOWLY LIFT TO MVFR BUT WILL LIKELY REMAIN BROKEN
THROUGH 14Z... NOT BECOMING VFR UNTIL AFTER 16Z. ADDITIONAL
SCATTERED STORMS ARE EXPECTED AFTER 18Z SUNDAY... BUT CONFIDENCE IN
THE TIMING AND LOCATION OF DEVELOPMENT PRECLUDES PLACING A
THUNDERSTORM MENTION IN THE AVIATION FORECAST AT THIS TIME.
LOOKING BEYOND EARLY SUNDAY EVENING... PATCHY IFR STRATUS AND MVFR
FOG ARE EXPECTED AT RDU/RWI/FAY LATE SUNDAY NIGHT THROUGH MONDAY
MORNING. AS A WARM AND HUMID AIR MASS HOLDS OVER THE REGION THROUGH
MID WEEK... DAILY OCCURRENCES OF AFTERNOON AND EARLY EVENING SHOWERS
AND STORMS WITH LOCALLY GUSTY WINDS AND MVFR CONDITIONS IN HEAVY
RAIN ARE POSSIBLE AT EACH TERMINAL THROUGH THURSDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...KRR
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
740 PM EDT SAT JUL 21 2012
.SYNOPSIS...
TYPICAL SUMMER TIME WEATHER WILL CONTINUE WITH BERMUDA HIGH PRESSURE
OFFSHORE AND SURFACE LOW PRESSURE INLAND PRODUCING SOUTHWEST WINDS
AND LOCALIZED THUNDERSTORMS TO THE COASTAL CAROLINAS. A BUILDING
RIDGE ALOFT WILL BRING A WARMING TREND THROUGH NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM SATURDAY...LATEST SFC ANALYSIS PLACES THE STATIONARY
FRONT JUST NORTH OF THE AREA...EXTENDING FROM ROUGHLY DUCK WESTWARD
ALONG OR JUST SOUTH OF THE NC-VA STATE BORDER. THIS KEEPS THE FA
WITHIN THE JUICY AIR MASS AND PAINTED WITH PWS OF 2+ INCHES. THE
MAJORITY OF THE DAYS CONVECTION HAS WANED ACROSS THE AREA AND WAS A
PRODUCT FROM SFC FORCING...IE. SEA BREEZE AND RESIDUAL OUTFLOW
BOUNDARIES. MID-LEVEL TROFFINESS WILL PERSIST TONIGHT AND INTO
SUNDAY. A WEAK IMPULSE EMBEDDED IN 5H FLOW IS PROGGED TO MOVE FROM
GSP THIS EVENING ACROSS PORTIONS OF THE FA OVERNIGHT TO THE SOUTHERN
OUTER BANKS AFTER SUNDAYS SUNRISE. THE DYNAMICS FROM THE IMPULSE
WILL BE ENOUGH TO IGNITE ISOLATED/SCATTERED TSRA DURING THE
OVERNIGHT. AND FOR THAT REASON HAVE KEPT AN ACTIVE OVERNIGHT
POP IN THE FORECAST. ANOTHER WARM AND STICKY NIGHT FOR THE FA...WITH
LOW TEMPS RANGING FROM THE MID 70S INLAND TO THE UPPER 70S TO AROUND
80 ALONG THE IMMEDIATE COAST. THE SFC PG IS NOT AS PRONOUNCED LIKE
PREVIOUS NIGHTS. THIS WILL RESULT IN SW WINDS 5 MPH OR LESS
INLAND...5 TO 15 MPH ALONG THE IMMEDIATE COAST. THE UPPER RANGE
LIMIT WILL OCCUR THIS EVENING DUE TO AN ACTIVE SEA BREEZE
CIRCULATION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...BERMUDA HIGH AND PIEDMONT TROUGH REMAIN TWO
DOMINANT SURFACE FEATURES CONTROLLING COASTAL CAROLINAS WEATHER.
THIS WILL MAINTAIN A SW SFC FLOW VEERING AROUND TO MORE WESTERLY
THROUGH THE LOW TO MID LEVELS. 850 TO 700 MB WINDS WILL BE 15 TO
25 KTS SUN AFTN INCREASING UP TO 20 TO 30 KTS MON AFTN AS THEY
VEER TOWARD THE NW. MID TO UPPER TROUGH LIFTS OFF TO THE NORTH
NORTHEAST AS RIDGE BUILDS IN FROM EAST AND WEST EXPANDING ACROSS
THE SOUTHEAST SUNDAY THROUGH MONDAY. ANY SHORTWAVE ENERGY TOPPING
THE RIDGE SHOULD REMAIN JUST TO NORTH OF LOCAL CWA. H5 HEIGHTS WILL
RISE UP TO 595 DEM AND WILL SEE INCREASED BUT WEAKER SUBSIDENCE
AND DRIER AIR THROUGH THE MID LEVELS. WITH BEST UPPER LEVEL SUPPORT
TO THE NORTH AND STRONG WESTERLY LOW TO MID LEVEL FLOW...EXPECT
MORE LOCALIZED CONVECTION ALONG CONVERGENT BOUNDARIES TYPICAL OF
SUMMERTIME...WITH BETTER CHC OVER NC. SEA BREEZE SHOULD REMAIN FAIRLY
CLOSE TO THE COAST WITH STRONGER WESTERLY COMPONENT TO
FLOW...ESPECIALLY ON MONDAY. THEREFORE ANY CONVECTION THAT FORMS
ALONG SEA BREEZE BOUNDARY WILL BE CLOSER TO THE COAST AND WILL
MOVE RAPIDLY OFF TO THE EAST TOWARD THE WATERS. ALSO EXPECT OTHER
SHWRS/TSTMS TO DEVELOP ALONG PIEDMONT TROUGH FURTHER INLAND AND
MOVE EAST TOWARD THE COAST. MOISTURE PROFILES DO SHOW VERY MOIST
UPPER LEVELS WITH WINDS ABOVE H4 HAVING GOOD NW-N COMPONENT.
THEREFORE EXPECT PERIODS OF CIRRUS...MAINLY FROM CONVECTIVE DEBRIS
CLOUDS FROM CONVECTION UPSTREAM. THIS SHOULD FILTER OUT SOME OF
THE SUN.
WITH RISING H5 HEIGHTS AND STRONG LOW LEVEL WESTERLY COMPONENT TO
THE FLOW...EXPECT WARM SUMMERTIME TEMPS RUNNING BETWEEN 90 AND 95
MOST PLACES.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...A RETURN TO HOT AND HUMID WEATHER EXPECTED
FOR MUCH OF THE EXTENDED...WITH ABOVE CLIMO PRECIP CHANCES THROUGH
LATE WEEK.
LARGE ELONGATED UPPER RIDGE EXTENDING FROM NEBRASKA SOUTHEAST INTO
FLORIDA WILL GET GRADUALLY PUSHED SOUTHWARD AS A LARGE UPPER LOW
ACROSS CANADA SHEARS OFF AND DROPS VORT IMPULSES INTO A BROAD
EASTERN LONGWAVE TROUGH. AS THIS OCCURS...W/NW FLOW DEVELOPS THROUGH
MUCH OF THE COLUMN ABOVE THE IMMEDIATE SURFACE. AT THE
SURFACE...LARGE BERMUDA HIGH PRESSURE GETS SHUNTED SOUTH AS
WELL...BUT NEAR SURFACE S/SW FLOW PERSISTS THROUGH THE PERIOD.
THE COMBINATION OF THE MID LEVEL TROUGH...850MB TEMPS AROUND
20C...AND MOIST RETURN SURFACE FLOW WILL CREATE DECENT CONVECTION
CHANCES EACH DAY...WITH WIDESPREAD COVERAGE POSSIBLE ESPECIALLY ON
WEDNESDAY. AN ACTIVE PIEDMONT TROUGH AND SEA BREEZE FRONT WILL OCCUR
EACH DAY...ALTHOUGH WITH THE DEEP W/NW FLOW THE SEA BREEZE WILL
REMAIN PINNED NEAR THE COAST. PWATS OF TWO INCHES OR GREATER AND
HIGH THETA-E AIR COMBINED WITH STEEP LOW LEVEL LAPSE RATES AND
SUBTLE VORT IMPULSES WILL SPAWN CONVECTION EACH AFTN...BUT MOST
ACTIVITY WILL BE DIURNALLY FORCED AND WILL KEEP INHERITED
CHC-BY-DAY...SILENT-BY-NIGHT POP. THE BEST TSTM COVERAGE WILL BE
WEDNESDAY AHEAD OF A COLD FRONT WHICH WILL TRY TO DROP SOUTH INTO
THE ILM CWA. EXPECT THIS BOUNDARY TO GET HUNG UP JUST NORTH OF THE
AREA...BUT THIS WILL STILL SERVE AS AN ADDITIONAL FOCUS FOR
CONVECTION DURING WED/WED NIGHT. OVERALL POP WILL TREND DOWNWARD
LATE IN THE PERIOD AS 500MB RIDGE BUILDS BACK TO THE NORTH.
HOWEVER...WILL KEEP SCHC POP (SILENT BY DAY 6/7) FOR ISOLATED TSTMS
IN A STILL VERY WARM/MOIST AIR MASS.
850MB TEMPS AROUND 20C WILL SUPPORT HIGHS WELL INTO THE 90S MOST
DAYS EVEN WITH THE LIMITING IMPACT OF CLOUD COVER. MINS AT NIGHT
WILL FALL ONLY INTO THE MID 70S...NEAR 80 SOME NIGHTS AT THE COAST.
&&
.AVIATION /00Z SATURDAY THROUGH THURSDAY/...
AS OF 00Z...CONVECTION IS REALLY WANING AT THIS POINT...WITH MAINLY
VCSH ADVERTISED IN THE TAFS. THE HRRR MODEL DOES DEPICT ANOTHER
BATCH OF CONVECTION AROUND 05Z...MOVING INTO THE NORTHWEST PORTION
OF THE CWA. THIS FEATURE PROBABLY HAS BEEN OVERDONE...AND THE LATEST
HOURLY RUN DOES WEAKEN IT A BIT.
MOSTLY MID AND HIGH CLOUD CONVECTIVE DEBRIS WILL BE THE RULE
OVERNIGHT...AREAS THAT RECEIVED DECENT RAINFALL...MAINLY LBT...COULD
SEE SOME MVFR FOG TOWARD SUNRISE. SUNDAY...CONTINUED SOUTHWEST
FLOW...A BIT WEAKER THAN TODAY. LIKEWISE DEEP MOISTURE IS A BIT LESS
THAN TODAY...BUT STILL COULD SQUEEZE OUT ISOLATED CONVECTION TOWARD
THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...CHANCE OF AFTERNOON THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM SATURDAY...THE ACTIVE BUT SOMEWHAT PINNED SEA BREEZE
WILL RESULT IN SSW-SW WINDS 15 TO OCCASIONALLY 20 KT THIS
EVENING...BEFORE FINALLY BACKING DOWN TO SW 10 TO 15 KT DURING THE
PRE-DAWN HRS OF SUNDAY. THE SFC PG WILL NOT BE NEARLY AS TIGHT LIKE
THE PREVIOUS FEW DAYS...AND THE NOCTURNAL 925MB JET IS NOT AS
PRONOUNCED LIKE THE PREVIOUS FEW DAYS. THUS...THE REASONS WHY THE
LOWER FORECAST SPEEDS FOR OVERNIGHT INTO SUNDAY. SIG SEAS WILL RUN 2
TO 4 FT AND BE RULED BY THE 5 TO 6 SECOND SHORT PERIOD LOCALLY
PRODUCED WIND DRIVEN WAVES. WAVEWATCH3 ILLUSTRATES AN INCREASE OF
THE 9-10 SECOND PERIOD ESE GROUND SWELL FROM 1/2 FT THIS EVENING TO
1+ FT BY SUNRISE SUNDAY. THIS WILL OFFSET THE SUBSIDING WIND DRIVEN
WAVE HEIGHTS AS A RESULT OF THE DIMINISHING WIND FIELD TONIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...SOUTHWEST FLOW WILL CONTINUE BETWEEN
BERMUDA HIGH TO THE EAST AND PIEDMONT TROUGH OVER INLAND
CAROLINAS. NAM SHOWING DECENT LOW LEVEL JETTING BOTH SUN AND MON
NIGHT BUT STRONGER MON NIGHT AS WINDS ALOFT INCREASE UP TO 25 TO
30 KTS. OVERALL EXPECT SFC WINDS AROUND 15 KTS SUNDAY INCREASING
UP TO 15 TO 20 KTS ON MONDAY AND VEERING SLIGHTLY MORE TO THE
W-SW. EACH AFTERNOON WINDS WILL BECOME SLIGHTLY MORE ON SHORE AND
GUSTIER CLOSE TO THE COAST AS SEA BREEZE DEVELOPS. WNA SHOWING
LONGER PERIOD UP TO 10 SECOND SWELLS MIXING WITH LOCALLY DRIVEN
WIND WAVES TO PRODUCE SEAS 2 TO 4 FT. SHOULD REACH UP TO 4 TO 5 FT
IN OUTER WATERS MON NIGHT IN STRONGER W-SW WINDS.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...TYPICAL SUMMERTIME PATTERN THROUGH THE
EXTENDED WITH PERSISTENT SW RETURN FLOW DOMINATING THE SYNOPTIC
WIND. SW WINDS OF 15-20 KTS WILL OCCUR ON BOTH TUESDAY AND
WEDNESDAY...EASING TO AROUND 10 KTS AND VEERING TO SLIGHTLY MORE
W/SW BY THURSDAY AS A BACK DOOR TYPE FRONT APPROACHES FROM THE
NORTH. THESE SW WINDS WILL KEEP A 4-5FT/5SEC SW WIND WAVE ONGOING
THROUGH THE PERIOD...ALTHOUGH AMPLITUDE WILL DECAY SLIGHTLY ON
THURSDAY. AT THE SAME TIME...THE PERSISTENT FLOW AROUND HIGH
PRESSURE RIDGE OVER THE ATLANTIC WILL KEEP A SE GROUND SWELL PRESENT
WITHIN THE WAVE SPECTRUM. SWELL INITIALLY OF 2FT/9SEC WILL BECOME
2FT/13 SEC BY THURSDAY. SEAS OF 3-5 FT TUESDAY WILL SLOWLY
DECREASE...BECOMING 2-3 FT THURSDAY THANKS TO EASING WINDS AND THE
LONGER PERIOD SWELL DECAYING MORE QUICKLY DUE TO OCEAN BOTTOM
FRICTION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
146 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT APPROACHING FROM THE NORTH WILL STALL OVER THE AREA
THROUGH THE WEEKEND...PROVIDING FOR UNSETTLED WEATHER. AS THE FRONT
BASICALLY DISSIPATES BY EARLY NEXT WEEK...HIGH TEMPERATURES ONCE
AGAIN WILL WARM TO LEVELS ABOVE NORMAL.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1005 AM FRIDAY...
THE LATEST SURFACE ANALYSIS SHOWED A WAVY FRONTAL BOUNDARY...WITH
SURFACE WAVES ALONG THE BOUNDARY...EXTENDING MAINLY ALONG AND NEAR
THE OHIO RIVER...THEN SOUTHEAST FROM SOUTHERN OHIO TOWARD DELMARVA.
A SURFACE TROUGH WAS ALSO LOCATED OVER THE FOOTHILLS AND FAR WESTERN
PIEDMONT. WHILE THE SURFACE GRADIENT WAS SLACK OVER CENTRAL NORTH
CAROLINA...AMDAR SOUNDINGS AS WELL AS THE KGSO 12Z SOUNDING SHOWED
SOME WINDS NEAR THE INVERSION AROUND 20KT. ALREADY...THERE HAVE BEEN
A COUPLE OF GUSTS APPROACHING 20KT ON SURFACE OBSERVATIONS...NOTABLY
AT KFAY.
WHILE DIFFICULT TO RESOLVE ON STANDARD WATER VAPOR IMAGERY...EARLY
MORNING VISIBLE IMAGERY WOULD SUGGEST AN MCV MOVING OVER FAR
NORTHEAST TENNESSEE...WHICH ESSENTIALLY ALL OF THE SHORT-TERM
GUIDANCE FORECASTS MOVING EAST OVER OR VERY NEAR CENTRAL NORTH
CAROLINA DURING THE AFTERNOON. THE RUC IS THE STRONGEST AMONG THE
GFS AND NAM...AND WHILE PRECIPITABLE WATER VALUES ARE CURRENTLY AT A
REGIONAL MINIMUM OVER THE WESTERN THIRD OF THE STATE ON THE LATEST
SPC MESOANALYSIS...WITH THE APPROACH OF THE MCV AND EXPECTED SLOW
EASTWARD PROGRESS OF THE SURFACE TROUGH IN RESPONSE...850MB THETA-E
ADVECTION FROM THE SOUTHWEST SHOULD LIMIT OR NULLIFY ANY
PRECIPITABLE WATER REDUCTION THIS AFTERNOON. 850MB DEW POINTS ARE IN
THE TEENS ON THE LATEST UPPER-AIR ANALYSIS AT THAT LEVEL.
MORNING LOW CLOUDS WERE GRADUALLY DIMINISHING ON THE LATEST VISIBLE
IMAGES...AND WHILE 1000-500MB LAPSE RATES ARE NOT FORECAST
PARTICULARLY HIGH THIS AFTERNOON...TO AROUND 6.5C/KM...AND DCAPE IS
FAIRLY LOW...AROUND 200J/KG...THE COMBINATION OF BETTER SYNOPTIC
FORCING...BETTER AVAILABLE LOW-LEVEL WINDS...AND SOME INCREASING
SHEAR LATE ESPECIALLY NORTHWEST...WHERE 0-6KM SHEAR SHOULD INCREASE
TO AROUND 25KT...SHOULD PROVIDE FOR THE POTENTIAL OF SOME
THUNDERSTORMS ORGANIZING ENOUGH TO HAVE A RISK FOR SEVERE WEATHER
WITH DAMAGING WIND THE PRIMARY SEVERE WEATHER THREAT. SREF
PROBABILISTIC FORECAST FOR GREATER THAN 100 CLOUD-TO-GROUND
LIGHTNING STRIKES SUGGESTS A MAXIMUM OVER THE WESTERN PIEDMONT...AND
THIS SEEMS REASONABLE WHERE THE -10C TO -30C CAPE IS A MAXIMUM...TO
AROUND 600J/KG. THE PREVIOUS FORECAST OF SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS DEVELOPING SEEMS VERY REASONABLE AND
CONTINUED THIS FOR THE AFTERNOON...INCREASING THE RAW NUMBERS ON THE
CHANCES FOR RAIN MAINLY TOWARD THE YADKIN RIVER TO JUST SHY OF
CATEGORICAL BASED ON THE CONSENSUS OF THE ABOVE...PLUS MOS GUIDANCE
AND THE LATEST HRRR WRF OUTPUT. TEMPERATURES IN MOST LOCATIONS...
AFTER A SLOW START IN THEIR RISE DUE TO CLOUDS...SHOULD REACH LOWER
TO MID 90S...POSSIBLY MORE OF A STRUGGLE TO REACH 90 IN THE
IMMEDIATE TRIAD. -DJF
TONIGHT...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL
EVENTUALLY DECREASE FROM W-E OR NW-SE AFTER MIDNIGHT IN ASSOC/W
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION. HOWEVER...WILL
KEEP AT LEAST 20-30% PRECIP CHANCES IN PLACE THE REMAINDER OF THE
NIGHT GIVEN AN APPROACHING UPPER LEVEL TROUGH IN THE PRESENCE OF A
VERY MOIST AND MARGINALLY UNSTABLE AIRMASS. LOW-LEVEL SHEAR BETWEEN
SUNSET AND MIDNIGHT (01-04Z) THIS EVENING (EAST OF HWY 1) IS PROGGED
TO BE SIMILAR TO THAT ANALYZED BY SPC MESOANALYSIS AT 09Z THIS
MORNING (150 M2/S2 OF 0-1 KM HELICITY AND 20-25 KT OF 0-1 KM BULK
SHEAR OVER CENTRAL/EASTERN NC). HOWEVER...DEEP CONVECTION WOULD HAVE
A DIFFICULT TIME REMAINING SFC-BASED BY THE TIME LOW-LEVEL SHEAR
STRENGTHENS IN CENTRAL NC...AND THE PROBABILITY OF A BRIEF/ISOLD TOR
IS TOO LOW TO MENTION. IF THERE WAS A VERY LOW-END POTENTIAL...IT
WOULD LIKELY BE EAST OF I-95 BETWEEN 01-04Z IN AREAS NOT STABILIZED
BY OUTFLOW AND/OR THE SEABREEZE. WITH A VERY MOIST LOW-LEVEL AIRMASS
IN PLACE...EXPECT LOWS TONIGHT IN THE LOWER 70S...OR 71-74F. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 145 AM FRIDAY...
PULSE THUNDERSTORMS WILL BRING LOCALLY VERY HEAVY RAIN AND GUSTY
WINDS BOTH SATURDAY AND SUNDAY.
A WEAK SURFACE COLD FRONT IS EXPECTED TO DRIFT SOUTHERLY SOUTH
THROUGH TN/WVA/VA SATURDAY... POSSIBLY REACHING NORTHERN NC LATE
SATURDAY AND SATURDAY NIGHT... BEFORE STALLING OVER OUR REGION INTO
SUNDAY. THE STRONG CONFLUENCE ALONG THIS FRONT WILL COMBINE WITH
STRONG SURFACE HEATING TO PROVIDE MORE THAN ADEQUATE LIFT OF VERY
MOIST AIR IN SUPPORT OF THE DEVELOPMENT OF NUMEROUS THUNDERSTORMS
AGAIN SATURDAY AFTERNOON INTO THE EVENING. AREAL AVERAGE QPF SHOULD
BE ON THE ORDER OF 0.50 TO 1 INCH... WITH SOME LOCALLY VERY HEAVY
AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE DUE TO THE MOISTURE POOLING
AND SLOW STORM MOVEMENT. THIS INFORMATION WILL CONTINUE TO BE
MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK (HWO). SUNDAY SHOULD
AGAIN BE JUST AS CONVECTIVELY ACTIVE WITH THE LOW LEVEL CONFLUENCE
ZONE BECOMING NEARLY STATIONARY OVER THE PIEDMONT. QPF SUNDAY WILL
AGAIN INDICATE 0.50 TO 1 INCH AREAL AVERAGES... WITH LOCALLY 2
INCHES AGAIN POSSIBLE. HOPEFULLY... THE HEAVIER AMOUNTS WILL FALL IN
DIFFERENT LOCATIONS THAN THOSE THAT RECEIVE HEAVY AMOUNTS BOTH
FRIDAY AND SATURDAY. THAT IS NOT ALWAYS THE CASE HOWEVER...
THEREFORE SOME LOCAL AREAS MAY RECEIVE OVER 4 INCHES OF RAIN TOTAL
TODAY THROUGH SUNDAY.
SHEAR IS FORECAST TO CONTINUE TO BE LACKING WHICH OFTEN WILL LEAD TO
THE CONVECTIVE MODE BEING "PULSE"... OR TYPICAL SUMMERTIME STRONG
THUNDERSTORMS. THIS MEANS LESS IN THE WAY OF ORGANIZED SEVERE
STORMS. HOWEVER... EVEN THOUGH "ORGANIZED AND WIDESPREAD" SEVERE
THUNDERSTORMS ARE NOT FORECAST... THERE WILL LIKELY BE BE A RAPID
DEVELOPMENT OF "PULSE" THUNDERSTORMS BOTH SATURDAY AND SUNDAY. SOME
OF THESE MAY BECOME LOCALLY SEVERE WITH DAMAGING WIND GUSTS TO 60
MPH POSSIBLE. WE WILL HIGHLIGHT THIS LOCAL PULSE SEVERE CHANCE AS
WELL IN THE HWO FOR BOTH DAYS. HIGHS SATURDAY ARE FAVORED TO BE IN
THE 86-92 RANGE... N TO S. LOWS SATURDAY NIGHT... 69-73. HIGHS
SUNDAY MAY BE A BIT COOLER (ONLY DUE TO THE FORECAST HIGH DEW POINTS
AND WETTER GROUND BY THEN) 85-90.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 145 AM FRIDAY...
ANOTHER HOT AND HUMID WEEK...WITH A CHANCE OF MAINLY AFTERNOON AND
EVENING THUNDERSTORMS.
STRONG UPPER RIDGING IS FORECAST TO BEGIN TO EXTEND EASTWARD FROM
THE CENTRAL UNITED STATES TO NEAR THE APPALACHIANS BY MID WEEK. THE
BOUNDARY THAT IS FORECAST TO BRING THE THUNDERSTORMS TO OUR REGION
THIS WEEKEND IS FORECAST TO DISSIPATE OVER OUR AREA MONDAY THROUGH
TUESDAY. AS WE LOSE THE INFLUENCE OF THE BOUNDARY (LIFT/MOISTURE
POOLING/CONVERGENCE) WE WILL SEE THE WIDESPREAD STORMS OF THE
WEEKEND BECOME SCATTERED DURING MONDAY AND TUESDAY. A NW FLOW ALOFT
MAY NOT TURN OUT TO BE THAT MUCH DRIER MID TO LATE WEEK AS
DISTURBANCES ALOFT MAY TRIGGER AT LEAST SCATTERED DIURNAL STORMS ALL
WEEK. WE WILL MAINTAIN POPS OF AT LEAST CLIMATOLOGY FOR LATE JULY
(35 PERCENT OR SO) MOST OF THE WEEK.
THE HEAT WILL ALSO BEGIN TO RETURN WITH LESS IN THE WAY OF CLOUDS/
STORMS DURING THE PM HOURS. THEREFORE...HIGHS ARE EXPECTED TO BE IN
THE UPPER 80S TO LOWER 90S MONDAY...90-95 TUESDAY... THEN MOSTLY MID
90S BY THURSDAY. IT WILL CONTINUE VERY MUGGY WITH DEW POINTS IN THE
70S. LOWS WILL ALSO BE IN THE 70S.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 145 PM FRIDAY...
VFR CONDITIONS WILL BE THE RULE OUTSIDE OF SHOWERS AND THUNDERSTORMS
THROUGH THIS EVENING. SHOWERS AND THUNDERSTORMS WILL PRODUCE LOCALLY
GUSTY WINDS...NOTE THE GUST TO 36KT AT KPOB AT 1718Z. OVERNIGHT...
IT IS DIFFICULT TO ASSESS THE POTENTIAL FOR LOW CLOUDS. THE HIGHER
WINDS JUST OFF OF THE SURFACE WILL BE TOWARD KFAY AND KRWI LATE
TONIGHT...WHILE THE SREF MODEL HAS ITS HIGHEST PROBABILITIES MOSTLY
FROM KGSO AND KRDU SOUTHWEST...AND HIGHER THAN IT INITIALIZED THIS
MORNING WHEN MVFR AND LOCALLY IFR CEILINGS OCCURRED ACROSS CENTRAL
NORTH CAROLINA. CONFIDENCE IS FAIRLY HIGH THAT THERE WILL BE AREAS
OF MVFR CEILINGS IN CENTRAL NORTH CAROLINA...BUT THE LOCATION OF THE
LOWER CEILINGS IS MORE UNCERTAIN. FOR THE 18Z VALID TAF...LEANED
TOWARD THE SREF OUTPUT WITH THE TEMPORARY CONDITIONS OF IFR CLOUDS
TOWARD KGSO AND KRDU...AND ONLY LOW MVFR CEILINGS AT KFAY AND KRWI
LATE TONIGHT AND EARLY SATURDAY AFTER SUNRISE.
BEYOND THE 18Z VALID TAF PERIOD...ANTICIPATE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS DEVELOPING IN A MOIST AIR MASS AGAIN BY LATE
SATURDAY MORNING...BECOMING MORE NUMEROUS DURING THE AFTERNOON AND
CONTINUING INTO SATURDAY EVENING. REMAINING SHOWERS SHOULD BECOME
MUCH MORE ISOLATED OR DIMINISH LATE SATURDAY NIGHT. SCATTERED
SHOWERS AND THUNDERSTORMS OCCUR AGAIN SUNDAY...THEN ANY SHOWERS AND
THUNDERSTORMS SHOULD TEND TO BECOME MORE ISOLATED EARLY NEXT WEEK AS
THE COLD FRONT MOVING SOUTH CURRENTLY FROM VIRGINIA STALLS AND
DISSIPATES. LATE NIGHT AND EARLY MORNING LOW CLOUDS ARE ALSO
POSSIBLE...WITH THE LATEST GUIDANCE SUGGESTING A BETTER POTENTIAL
LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SEC/DJF
NEAR TERM...DJF/VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1005 AM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTH TODAY AS AN UPPER LEVEL
DISTURBANCE PROGRESSES SOUTHEAST FROM THE OHIO VALLEY INTO THE
CAROLINAS. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED THIS AFTERNOON THROUGH THE WEEKEND AS THE FRONT STALLS OUT
OVER THE REGION.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1005 AM FRIDAY...
THE LATEST SURFACE ANALYSIS SHOWED A WAVY FRONTAL BOUNDARY...WITH
SURFACE WAVES ALONG THE BOUNDARY...EXTENDING MAINLY ALONG AND NEAR
THE OHIO RIVER...THEN SOUTHEAST FROM SOUTHERN OHIO TOWARD DELMARVA.
A SURFACE TROUGH WAS ALSO LOCATED OVER THE FOOTHILLS AND FAR WESTERN
PIEDMONT. WHILE THE SURFACE GRADIENT WAS SLACK OVER CENTRAL NORTH
CAROLINA...AMDAR SOUNDINGS AS WELL AS THE KGSO 12Z SOUNDING SHOWED
SOME WINDS NEAR THE INVERSION AROUND 20KT. ALREADY...THERE HAVE BEEN
A COUPLE OF GUSTS APPROACHING 20KT ON SURFACE OBSERVATIONS...NOTABLY
AT KFAY.
WHILE DIFFICULT TO RESOLVE ON STANDARD WATER VAPOR IMAGERY...EARLY
MORNING VISIBLE IMAGERY WOULD SUGGEST AN MCV MOVING OVER FAR
NORTHEAST TENNESSEE...WHICH ESSENTIALLY ALL OF THE SHORT-TERM
GUIDANCE FORECASTS MOVING EAST OVER OR VERY NEAR CENTRAL NORTH
CAROLINA DURING THE AFTERNOON. THE RUC IS THE STRONGEST AMONG THE
GFS AND NAM...AND WHILE PRECIPITABLE WATER VALUES ARE CURRENTLY AT A
REGIONAL MINIMUM OVER THE WESTERN THIRD OF THE STATE ON THE LATEST
SPC MESOANALYSIS...WITH THE APPROACH OF THE MCV AND EXPECTED SLOW
EASTWARD PROGRESS OF THE SURFACE TROUGH IN RESPONSE...850MB THETA-E
ADVECTION FROM THE SOUTHWEST SHOULD LIMIT OR NULLIFY ANY
PRECIPITABLE WATER REDUCTION THIS AFTERNOON. 850MB DEW POINTS ARE IN
THE TEENS ON THE LATEST UPPER-AIR ANALYSIS AT THAT LEVEL.
MORNING LOW CLOUDS WERE GRADUALLY DIMINISHING ON THE LATEST VISIBLE
IMAGES...AND WHILE 1000-500MB LAPSE RATES ARE NOT FORECAST
PARTICULARLY HIGH THIS AFTERNOON...TO AROUND 6.5C/KM...AND DCAPE IS
FAIRLY LOW...AROUND 200J/KG...THE COMBINATION OF BETTER SYNOPTIC
FORCING...BETTER AVAILABLE LOW-LEVEL WINDS...AND SOME INCREASING
SHEAR LATE ESPECIALLY NORTHWEST...WHERE 0-6KM SHEAR SHOULD INCREASE
TO AROUND 25KT...SHOULD PROVIDE FOR THE POTENTIAL OF SOME
THUNDERSTORMS ORGANIZING ENOUGH TO HAVE A RISK FOR SEVERE WEATHER
WITH DAMAGING WIND THE PRIMARY SEVERE WEATHER THREAT. SREF
PROBABILISTIC FORECAST FOR GREATER THAN 100 CLOUD-TO-GROUND
LIGHTNING STRIKES SUGGESTS A MAXIMUM OVER THE WESTERN PIEDMONT...AND
THIS SEEMS REASONABLE WHERE THE -10C TO -30C CAPE IS A MAXIMUM...TO
AROUND 600J/KG. THE PREVIOUS FORECAST OF SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS DEVELOPING SEEMS VERY REASONABLE AND
CONTINUED THIS FOR THE AFTERNOON...INCREASING THE RAW NUMBERS ON THE
CHANCES FOR RAIN MAINLY TOWARD THE YADKIN RIVER TO JUST SHY OF
CATEGORICAL BASED ON THE CONSENSUS OF THE ABOVE...PLUS MOS GUIDANCE
AND THE LATEST HRRR WRF OUTPUT. TEMPERATURES IN MOST LOCATIONS...
AFTER A SLOW START IN THEIR RISE DUE TO CLOUDS...SHOULD REACH LOWER
TO MID 90S...POSSIBLY MORE OF A STRUGGLE TO REACH 90 IN THE
IMMEDIATE TRIAD. -DJF
TONIGHT...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL
EVENTUALLY DECREASE FROM W-E OR NW-SE AFTER MIDNIGHT IN ASSOC/W
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION. HOWEVER...WILL
KEEP AT LEAST 20-30% PRECIP CHANCES IN PLACE THE REMAINDER OF THE
NIGHT GIVEN AN APPROACHING UPPER LEVEL TROUGH IN THE PRESENCE OF A
VERY MOIST AND MARGINALLY UNSTABLE AIRMASS. LOW-LEVEL SHEAR BETWEEN
SUNSET AND MIDNIGHT (01-04Z) THIS EVENING (EAST OF HWY 1) IS PROGGED
TO BE SIMILAR TO THAT ANALYZED BY SPC MESOANALYSIS AT 09Z THIS
MORNING (150 M2/S2 OF 0-1 KM HELICITY AND 20-25 KT OF 0-1 KM BULK
SHEAR OVER CENTRAL/EASTERN NC). HOWEVER...DEEP CONVECTION WOULD HAVE
A DIFFICULT TIME REMAINING SFC-BASED BY THE TIME LOW-LEVEL SHEAR
STRENGTHENS IN CENTRAL NC...AND THE PROBABILITY OF A BRIEF/ISOLD TOR
IS TOO LOW TO MENTION. IF THERE WAS A VERY LOW-END POTENTIAL...IT
WOULD LIKELY BE EAST OF I-95 BETWEEN 01-04Z IN AREAS NOT STABILIZED
BY OUTFLOW AND/OR THE SEABREEZE. WITH A VERY MOIST LOW-LEVEL AIRMASS
IN PLACE...EXPECT LOWS TONIGHT IN THE LOWER 70S...OR 71-74F. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 145 AM FRIDAY...
PULSE THUNDERSTORMS WILL BRING LOCALLY VERY HEAVY RAIN AND GUSTY
WINDS BOTH SATURDAY AND SUNDAY.
A WEAK SURFACE COLD FRONT IS EXPECTED TO DRIFT SOUTHERLY SOUTH
THROUGH TN/WVA/VA SATURDAY... POSSIBLY REACHING NORTHERN NC LATE
SATURDAY AND SATURDAY NIGHT... BEFORE STALLING OVER OUR REGION INTO
SUNDAY. THE STRONG CONFLUENCE ALONG THIS FRONT WILL COMBINE WITH
STRONG SURFACE HEATING TO PROVIDE MORE THAN ADEQUATE LIFT OF VERY
MOIST AIR IN SUPPORT OF THE DEVELOPMENT OF NUMEROUS THUNDERSTORMS
AGAIN SATURDAY AFTERNOON INTO THE EVENING. AREAL AVERAGE QPF SHOULD
BE ON THE ORDER OF 0.50 TO 1 INCH... WITH SOME LOCALLY VERY HEAVY
AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE DUE TO THE MOISTURE POOLING
AND SLOW STORM MOVEMENT. THIS INFORMATION WILL CONTINUE TO BE
MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK (HWO). SUNDAY SHOULD
AGAIN BE JUST AS CONVECTIVELY ACTIVE WITH THE LOW LEVEL CONFLUENCE
ZONE BECOMING NEARLY STATIONARY OVER THE PIEDMONT. QPF SUNDAY WILL
AGAIN INDICATE 0.50 TO 1 INCH AREAL AVERAGES... WITH LOCALLY 2
INCHES AGAIN POSSIBLE. HOPEFULLY... THE HEAVIER AMOUNTS WILL FALL IN
DIFFERENT LOCATIONS THAN THOSE THAT RECEIVE HEAVY AMOUNTS BOTH
FRIDAY AND SATURDAY. THAT IS NOT ALWAYS THE CASE HOWEVER...
THEREFORE SOME LOCAL AREAS MAY RECEIVE OVER 4 INCHES OF RAIN TOTAL
TODAY THROUGH SUNDAY.
SHEAR IS FORECAST TO CONTINUE TO BE LACKING WHICH OFTEN WILL LEAD TO
THE CONVECTIVE MODE BEING "PULSE"... OR TYPICAL SUMMERTIME STRONG
THUNDERSTORMS. THIS MEANS LESS IN THE WAY OF ORGANIZED SEVERE
STORMS. HOWEVER... EVEN THOUGH "ORGANIZED AND WIDESPREAD" SEVERE
THUNDERSTORMS ARE NOT FORECAST... THERE WILL LIKELY BE BE A RAPID
DEVELOPMENT OF "PULSE" THUNDERSTORMS BOTH SATURDAY AND SUNDAY. SOME
OF THESE MAY BECOME LOCALLY SEVERE WITH DAMAGING WIND GUSTS TO 60
MPH POSSIBLE. WE WILL HIGHLIGHT THIS LOCAL PULSE SEVERE CHANCE AS
WELL IN THE HWO FOR BOTH DAYS. HIGHS SATURDAY ARE FAVORED TO BE IN
THE 86-92 RANGE... N TO S. LOWS SATURDAY NIGHT... 69-73. HIGHS
SUNDAY MAY BE A BIT COOLER (ONLY DUE TO THE FORECAST HIGH DEW POINTS
AND WETTER GROUND BY THEN) 85-90.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 145 AM FRIDAY...
ANOTHER HOT AND HUMID WEEK...WITH A CHANCE OF MAINLY AFTERNOON AND
EVENING THUNDERSTORMS.
STRONG UPPER RIDGING IS FORECAST TO BEGIN TO EXTEND EASTWARD FROM
THE CENTRAL UNITED STATES TO NEAR THE APPALACHIANS BY MID WEEK. THE
BOUNDARY THAT IS FORECAST TO BRING THE THUNDERSTORMS TO OUR REGION
THIS WEEKEND IS FORECAST TO DISSIPATE OVER OUR AREA MONDAY THROUGH
TUESDAY. AS WE LOSE THE INFLUENCE OF THE BOUNDARY (LIFT/MOISTURE
POOLING/CONVERGENCE) WE WILL SEE THE WIDESPREAD STORMS OF THE
WEEKEND BECOME SCATTERED DURING MONDAY AND TUESDAY. A NW FLOW ALOFT
MAY NOT TURN OUT TO BE THAT MUCH DRIER MID TO LATE WEEK AS
DISTURBANCES ALOFT MAY TRIGGER AT LEAST SCATTERED DIURNAL STORMS ALL
WEEK. WE WILL MAINTAIN POPS OF AT LEAST CLIMATOLOGY FOR LATE JULY
(35 PERCENT OR SO) MOST OF THE WEEK.
THE HEAT WILL ALSO BEGIN TO RETURN WITH LESS IN THE WAY OF CLOUDS/
STORMS DURING THE PM HOURS. THEREFORE...HIGHS ARE EXPECTED TO BE IN
THE UPPER 80S TO LOWER 90S MONDAY...90-95 TUESDAY... THEN MOSTLY MID
90S BY THURSDAY. IT WILL CONTINUE VERY MUGGY WITH DEW POINTS IN THE
70S. LOWS WILL ALSO BE IN THE 70S.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 1005 AM FRIDAY...
MVFR CEILINGS WILL LIFT AND BECOME VFR DURING THE MORNING...WITH
MOSTLY VFR CONDITIONS EXPECTED THEREAFTER THROUGH 12Z. SURFACE WINDS
WILL SHOW SOME GUSTINESS...POSSIBLY TO NEAR 20KT PARTICULARLY TOWARD
KFAY AND KRWI THIS AFTERNOON. NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP OVER CENTRAL NC THIS AFTERNOON AND LINGER INTO
THIS EVENING AS A COLD FRONT APPROACHES THE AREA FROM THE NORTH.
WILL MENTION VCSH AT ALL TAF SITES BY 17-18Z...WITH A TEMPO GROUP
FOR IFR CONDITIONS AND GUSTY WINDS BETWEEN 18-22Z AT INT/GSO AND
19-23Z AT RDU/RWI/FAY...WHEN DEEP CONVECTION WILL BE MOST LIKELY.
ISOLD TO SCATTERED SHOWERS AND STORMS WILL REMAIN POSSIBLE THROUGH
THE END OF THE TAF PERIOD...THOUGH CONVECTION SHOULD WEAKEN AND
DECREASE IN COVERAGE AFTER 03Z THIS EVENING.
LOOKING AHEAD:
EXPECT SCATTERED TO NUMEROUS SHOWERS AND STORMS DURING THE AFTERNOON
AND EVENING HOURS SATURDAY AND SUNDAY AS THE FRONT STALLS OUT OVER
VA/NC. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE
PRE-DAWN HOURS EACH MORNING IN ASSOCIATION WITH A MOIST AIRMASS IN
PLACE. AFTERNOON AND EVENING SHOWERS/STORMS AND PRE-DAWN FOG/STRATUS
WILL REMAIN POSSIBLE THROUGH EARLY/MID NEXT WEEK IN ASSOCIATION WITH
A SEASONABLY MOIST AIRMASS IN THE PRESENCE OF NW FLOW ALOFT. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF/VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...DJF/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
435 PM EDT FRI JUL 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL MOVE ACROSS THE AREA THROUGH THE WEEKEND.
A COLD FRONT WILL APPROACH FROM THE NORTH BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LINE OF CONVECTION AHEAD OF A COLD FRONT WILL CONTINUE TO PUSH
SOUTH OUT OF THE REGION LATE THIS AFTERNOON INTO THE EARLY
EVENING. CONSIDERABLE LOW CLOUD COVER WILL START TO CLEAR FROM
THE NORTHWEST DURING THIS TIME FRAME. LATEST RAP RUNS SUGGEST THAT
CLEARING SHOULD ACCELERATE ACROSS A GOOD PART OF THE AREA LATER IN
THE EVENING. BUT STILL SOME QUESTION WHETHER/WHEN CLOUDS WILL
DIMINISH IN SOUTHEASTERN ZONES. NOT OUT OF THE QUESTION THAT THERE
COULD BE SOME FOG DEVELOPMENT WHERE SKIES CLEAR ALTHOUGH DRYING
LOW LEVELS SHOULD OFFSET THAT POTENTIAL AT LEAST SOMEWHAT.
FORECAST LOWS ARE SLIGHTLY ABOVE MOS CONSENSUS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
HIGH PRESSURE WILL BUILD INTO THE REGION TOMORROW AND MOVE OFF TO
THE SOUTHEAST ON SUNDAY. THIS WILL BRING A DRIER AIR MASS ACROSS
THE REGION. BUT RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL
SLOWLY INCREASE DEW POINTS ONCE AGAIN. A SHORT WAVE WILL MOVE
SOUTHEAST ACROSS THE REGION SATURDAY NIGHT BUT THIS SHOULD ONLY
BRING MID AND HIGH CLOUDS. GUIDANCE IS SUGGESTING THAT A LOW
LEVEL JET WILL PUSH INTO THE LOWER GREAT LAKES SUNDAY NIGHT WHICH
COULD RESULT IN SOME SHOWERS AND THUNDERSTORMS DEVELOPING NORTH OF
THE AREA LATE. KEPT POPS LOW AT THIS POINT BUT WILL HAVE TO
CONTINUE TO WATCH THIS POTENTIAL.
ANY COOLING WITH THIS HIGH WILL BE BRIEF AS UPPER HEIGHTS REMAIN
FAIRLY HIGH WITH THE PERSISTENT RIDGE JUST WEST OF THE REGION.
HAVE FORECAST HIGHS NEAR OR ABOVE WARMER NAM MOS GUIDANCE BUT WENT
WITH MORE OF A BLEND DURING THE NIGHT PERIODS. HOWEVER IF CLOUDS
ARE MORE EXTENSIVE THAN FORECAST...LOWS MAY END UP BEING SEVERAL
DEGREES WARMER.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
MODEL AGREEMENT FOR THE EXTENDED PERIOD REMAINS IN FAIR SHAPE...IN
TERMS OF THE LARGE SCALE FEATURES. GFS ENSEMBLE MEANS CONTINUE TO
SHOW A RELATIVELY SMALL AMOUNT OF SPREAD THROUGH THE END OF NEXT
WEEK. THE OVERALL PATTERN WILL BEGIN WITH THE CONTINUED DOMINANCE OF
A BROAD CENTRAL US RIDGE...WHICH LOSES ITS INFLUENCE OVER THE
EASTERN US AS TROUGHING OVER NEW ENGLAND LEADS TO GRADUAL (AND WEAK)
HEIGHT FALLS IN THE OHIO VALLEY AS THE WEEK PROGRESSES.
THE TRANSITION INTO A NW FLOW REGIME OVER THE OHIO VALLEY WILL LEAD
TO INCREASED CHANCES OF PRECIPITATION AT TIMES DURING THE WEEK.
PREVIOUS GFS/ECMWF MODEL RUNS HAVE NOT BEEN CONSISTENT ON THE
LOCATION OF THE FORCING OR TIMING OF THE BEST PRECIPITATION
CHANCES...BUT THE 12Z RUNS TODAY ARE SIMILAR ENOUGH TO PROVIDE SOME
CONFIDENCE IN THE SPECIFICS OF THE FORECAST. THE HIGHEST MAGNITUDE
OF HEIGHT FALLS WILL OCCUR ON TUESDAY...WITH A WEAK SURFACE FRONT
ALSO MOVING SOUTH INTO THE REGION. POPS HAVE BEEN INCREASED TO THE
30-40 RANGE FOR TUESDAY AFTERNOON. SOME DEGREE OF PRECIPITATION
CHANCES (THOUGH LESS ORGANIZED) WILL CONTINUE THROUGH THE REST OF
THE WEEK...AS THE NEAR-SURFACE BOUNDARY MOVES JUST ENOUGH TO THE
NORTHEAST TO KEEP THE CWA MORE FIRMLY INTO THE SOUTHERN AIR MASS
(WITH GREATER MOISTURE).
THE OVERALL CHANGES TO THE AIR MASS DURING THE EXTENDED WILL BE
SMALL...SO THE TEMPERATURE FORECAST WILL REMAIN MOSTLY UNCHANGED.
WHILE THE OVERALL TREND WILL BE FOR LITTLE CHANGE FROM ONE DAY TO TH
NEXT (WITH MAX TEMPS IN THE LOWER 90S)...WHAT ENDS UP HAPPENING FROM
DAY TO DAY WILL ALMOST CERTAINLY BE INFLUENCED BY CONVECTION OR
LEFTOVER CLOUDS. MONDAY DOES APPEAR TO BE THE WARMEST DAY OF THE
WEEK AT THIS TIME...WITH ONLY VERY LOW CHANCES OF RAIN AND WITH THE
RIDGE STILL HAVING THE GREATEST INFLUENCE.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
LINE OF CONVECTION HAS DEVELOPED ALONG A COLD FRONT RUNNING FROM
NR CVG/LUK-HOC-RZT. THIS PUTS THE FRONT THROUGH THE TAFS. EXCEPT
FOR A STRAY SHOWER AROUND ILN AT THE VERY BEGINNING OF THE PERIOD
THE TAFS SHOULD BE DRY.
IFR/MVFR CLDS HAVE BEEN STUBBORN TO RISE. CLEARING IS BACK IN NRN
INDIANA...BUT IT APPEARS THAT IS WILL BE SLOW TO REACH THE TAFS.
THINK THAT THE CIGS WILL RISE...BUT WILL STAYING MVFR THIS AFTN.
SCATTERED OUT CLDS AT DAY AROUND 02Z AND CVG/LUK AROUND 04Z. KEPT
CMH/LCK MVFR CIGS THE ENTIRE NIGHT.
SHOULD SEE FOG REDEVELOP OVERNIGHT...ESPECIALLY IN THE W...WHERE
THE CLOUDS SCT OUT. BROUGHT VSBYS DOWN TO 1SM IN THE WEST BETWEEN
08-12Z. IT MIGHT GO LOWER...BUT CONFIDENCE ISNT HIGH ENOUGH TO
PUT IT IN TAFS THAT FAR OUT ATTM.
MVFR CU SHOULD REDEVELOP TOMORROW MORNING AS FOG DISSIPATES...BUT
THEN SHOULD RISE TO VFR BY THE TIME THE TAFS PERIOD ENDS.
OUTLOOK...THUNDERSTORMS POSSIBLE TUESDAY AND WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
149 AM EDT FRI JUL 20 2012
.SYNOPSIS...
AN UPPER SHORT WAVE...COMBINED WITH ABUNDANT MOISTURE AND DIURNAL
HEATING PROVIDE UNSTABLE CONDITIONS THROUGH FRIDAY. A COLD FRONT WILL
MOVE THROUGH THE AREA FRIDAY. HIGH PRESSURE BUILDS IN FRIDAY NIGHT
INTO SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...
MORE CONVECTION TRIGGERED BY A SHORT WAVE ALOFT TO PUSH INTO THE
SOUTHEAST OHIO COUNTIES IN THE NEXT HOUR OR SO. LOCAL MODELS
CONTINUE TO INDICATE INITIATION THROUGH DAWN...AND KEEP THE POPS
RELATIVELY HIGH.
PREVIOUS DISCUSSION...
AN APPROACHING UPPER LEVEL TROUGH WILL PROVIDE ENOUGH
FORCING OVER A HIGH CAPE...HIGH PRECIPITABLE WATER ENVIRONMENT
THROUGH FRIDAY.
SEVERAL BANDS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP AND MOVE
FROM THE WEST THIS EVENING AND LATER TONIGHT. HPC QPF GUIDANCE
SUGGEST NEAR 3 INCHES MAINLY NORTHERN WV PANHANDLE...SOUTH ALONG
THE OH RIVER INTO PKB THROUGH 12Z FRIDAY.
EXPECT HEAVY DOWNPOURS WITH EVERY SINGLE STORM. MODELS SHOW PRECIPITABLE
WATER EXCEEDING 2 INCHES THROUGH THIS AFTERNOON THROUGH FRIDAY.
THE NAM AND HPC SUGGEST A STRONGER SHOT OF PRECIPITATION OVERNIGHT
TONIGHT. A MODERATE RISK FOR EXCESSIVE RAINFALL STILL IN EFFECT FROM
HPC THROUGH 00Z SATURDAY. DUE TO YESTERDAYS RAINFALL AMOUNTS
MEASURED BY RAIN GAGE...BETWEEN 0.5 TO 1.8 INCHES ACROSS NORTH
CENTRAL WV...WHILE RADAR STORM TOTALS...ALTHOUGH
OVERESTIMATED...SHOWED HIGHER AMOUNTS AWAY FROM GROUND
GAGES...GROUNDS ARE NEARLY SATURATED. BESIDES THESE AREAS ARE MORE
PRONE TO FLOODING. THEREFORE...KEPT FLASH FLOOD WATCH FOR SEVERAL
COUNTIES ACROSS THE CENTRAL AND NORTH CENTRAL WV...INCLUDING
ATHENS COUNTY IN SOUTHEAST OH.
ADJUSTED POPS CLOSER TO THE HRRR PER BETTER AGREEMENT ON LACK OF
AFTERNOON CONVECTION...WHILE OTHER MESO AND SYNOPTIC MODELS
OVERDUE PCPN. A DISORGANIZED MCS TYPE FEATURE CONTINUES TO PRODUCE
BANDS OF THUNDERSTORMS ACROSS OH. THE FIRST BAND HAVE REACHED
SOUTHEAST OH BY MID AFTERNOON...AND IS EXPECTED TO MOVE EAST TO
AFFECT THE FLASH FLOOD WATCH AREA EARLY THIS EVENING. ADDITIONAL
BAND OF STORMS ARE EXPECTED TO DEVELOP OVERNIGHT POSING THE THREAT
FOR SIGNIFICANT RAIN ACCUMULATIONS.
MOIST...WARM...AND HIGH SFC CAPE ENVIRONMENT REMAIN IN PLACE ON
FRIDAY...WHILE A SECONDARY VORT MAX MOVES ACROSS ASSOCIATED WITH
THE AFOREMENTIONED UPPER TROUGH. THEREFORE...KEPT HIGH LIKELY POPS
THROUGH THE END OF THE PERIOD FOCUSING THE EASTERN HALF OF THE
AREA.
WENT CLOSER TO THE LAV/MAV NUMBERS THROUGH THE PERIOD.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
BY FRIDAY EVENING THE COLD FRONT IS EXPECTED TO BE NEAR THE OHIO
RIVER. MEANWHILE BEST LARGE SCALE FORCING FOR ASCENT IS LOCATED OVER
THE NORTHEAST PART OF FORECAST AREA. IN ADDITION...A VORT MAX WILL
BE PUSHING SE-WARD ACROSS NORTHERN WV...WITH LIFT ASSOC WITH IT OUT
AHEAD ACROSS NE PART OF CWA. FINALLY...WITH COLD FRONT MOVING INTO
NORTHERN PART OF AREA AND GOOD LLVL MOISTURE CONVERGENCE
NOTED...SHOWERS/STORMS A GOOD BET TO CONTINUE ACROSS MUCH OF THE
AREA WITH THE HIGHEST POPS WEIGHTED ACROSS NE ZONES BY THE EVENING
HOURS. THOUGH GREATEST COVERAGE IS EXPECTED NORTHEAST...BETTER
CHANCE AT STRONG TO SVR WX APPEARS TO BE ACROSS SOUTHERN AND WESTERN
PARTS OF FORECAST AREA WHERE MARGINAL SHEAR COINCIDES BEST WITH
HIGHEST AXIS OF INSTABILITY. HEAVY DOWNPOURS AND STRONG WINDS
CONTINUE TO BE THE PRIMARY HAZARDS MAINLY BTWN 00Z-03Z. DCAPE VALUES
OF BTWN 500J-800J WITH SFC-MIDLEVEL THETA-E DIFFERENCES OF ~25C
PARTICULARLY ACROSS THE WEST ZONES INDICATE BETTER POTENTIAL FOR
STRONG DOWNBURST WINDS IN THESE LOCALES. SHOWERS/STORMS WILL PUSH
EASTWARD AND SOUTHWARD OVERNIGHT WITH DIMINISHING INTENSITY WITH
LOSS OF INSTABILITY.
BY SATURDAY MORNING COLD FRONT SHOULD BE LOCATED ACROSS THE
SOUTHEAST PART OF CWA WITH LARGE SCALE FORCING FOR SUBSIDENCE
OVERSPREADING THE AREA FROM NW/SE. BEST DEEP LAYER MOISTURE WILL BE
LOCATED NEAR AND AHEAD OF THE FRONT AND THUS WILL CONTINUE SLIGHT
CHANCE/LOW CHANCE POPS IN THIS AREA. FRONTAL ZONE WILL STALL TO THE
SOUTH AND SOUTHEAST ALONG WITH MOISTURE WITH CONTINUED CHANCE OF
SHOWERS AND THUNDERSTORMS PRIMARILY FAR EAST AND SOUTH THE REMAINDER
OF SATURDAY. WILL CONTINUE PRIMARILY SLIGHT CHANCE POPS SUNDAY AGAIN
PRIMARILY FOR FAR EASTERN AND SOUTHERN ZONES AS INSTABILITY AND LLVL
MOISTURE REMAIN ENTRENCHED IN THOSE AREAS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
OPERATIONAL EXTENDED NWP CONTINUES TO BE IN REASONABLY GOOD
AGREEMENT REGARDING GENERAL FEATURES DURING THIS PERIOD...DEPICTING
A STRENGTHENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS/HIGH PLAINS
REGION WITH ANOTHER OFF SE ATLANTIC COAST...WITH WNW/NW FLOW ALOFT
OVER FORECAST AREA THROUGH MUCH OF THE PERIOD. AS UPPER HIGH
ATTEMPTS TO BUILD EASTWARD...MAX TEMPS WILL REMAIN SLIGHTLY ABOVE
NORMAL LEVEL WITH READING CONTINUING IN THE UPPER 80S/LOWER 90S
LOWLAND AREAS. EXTENDED NWP AND ENSEMBLES ALSO IN DECENT AGREEMENT
WITH MOVING A FRONT INTO THE AREA TUESDAY AND WILL GO AHEAD AND
RAISE POPS INTO THE LOW CHANCE CATEGORY FOR THIS PERIOD. DIFFERENCES
ARISE HOWEVER WITH THE HANDLING OF THIS FRONT HOWEVER AND WILL USE A
BLEND WITH A LEANING TOWARDS THE EC WITH REGARD TO DAYS 6-7. TEMPS
WILL GENERALLY CONTINUE IN THE UPPER 80S/LOWER 90S FOR THE
PERIOD...PERHAPS A FEW DEGREES COOLER TUESDAY WITH THE FRONT/MORE
CLOUDS IN AREA.
&&
.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
SURFACE LOW RIDING INTO THE MIDDLE OHIO VALLEY COUPLED WITH
DISTURBANCES ALOFT AND PLENTY OF MOISTURE MAKES FOR A COMPLEX
AVIATION FORECAST TONIGHT. DESPITE CLOUD COVER...FOG HAS DEVELOPED
AT CRW...WITH IFR TO LIFR CEILINGS AT PKB AND EKN. WITH CONVECTION
CONTINUING OVERNIGHT...EXPECT OBSERVATIONS TO BOUNCE...REDUCING
OVERALL CONFIDENCE IN THE FORECAST. THESE CEILINGS COULD LIFT WITH
ANY RAIN...AS WOULD THE VISIBILITY AT CRW UNDER SIMILAR
CONDITIONS. MORE CONVECTION EXPECTED DURING THE DAY FRIDAY BEFORE
ENDING LATE FRIDAY EVENING AND FRIDAY NIGHT. TAFS WARRANT PLENTY
OF VCTS/CB DURING THE LATE MORNING AND AFTERNOON HOURS TODAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF THUNDERSTORMS AND ANY
CATEGORY CHANGES MAY VARY. MORNING FOG COVERAGE MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 07/20/12
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H H H H H M M H
HTS CONSISTENCY H H H H H H H H M M M H
BKW CONSISTENCY M M H H H H H H H H H M
EKN CONSISTENCY H H H H H M M M M M L M
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M M M M H H H H H H H H
AFTER 06Z SATURDAY...
IFR FOG POSSIBLE EARLY SATURDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JS/ARJ/50
NEAR TERM...ARJ/26
SHORT TERM...50
LONG TERM...50
AVIATION...26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
518 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN DRAPED ACROSS SOUTH CENTRAL
PENNSYLVANIA INTO THE NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD SOUTH ACROSS THE AREA SUNDAY AND MONDAY. TEMPERATURES FOR
MUCH OF NEXT WEEK WILL RETURN TO NEAR...OR SLIGHTLY ABOVE NORMAL.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
TSRA HAVE FORMED OVER SWRN PA AND ARE MOVING INTO THE LAURELS.
THIS AREA HAS BEEN PINPOINTED BY THE NAM AND RUC FOR THE PAST FEW
RUNS TO RECEIVE THE HEAVIEST RAINFALL OVER THE NEXT 6-9 HOURS.
BEST LLVL CONVERGENCE EXISTS THERE WITH FRONT INCHING SOUTHWARD.
SLIM BREAKS IN THE CLOUDS OVER SWRN PA HAVE ALLOW THE STABILITY TO
DROP AND CAPES TO CLIMB THE NAM HAS BEEN HANDLING THIS SITUATION
WELL WITH THE 06 AND 12Z RUNS. SINCE THEY HAVE HAD SIMILAR 1 TO
1.5 INCH AMOUNTS OF RAIN OVER THE PAST 36 HRS IN THE
LAURELS...HAVE EXPANDED THE FFA WESTWARD. CANCELLED THE FFA OVER
THE SERN COS - STABILITY IS HIGHER IN THE SE...BUT 0.5 TO 1 INCH
AMOUNTS ARE STILL POSSIBLE THERE THROUGH SUNSET. THESE AMOUNTS
SHOULD NOT BE ENOUGH TO CAUSE FLASH FLOODING IN THE SE. THE
STORMS IN THE SWRN COS WILL MOST LIKELY EXPAND AND SHOULD DROP
SLOWLY TO THE E/SE THIS EVENING...TAPERING OFF BY MIDNIGHT.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
LOW LEVEL FLOW REMAINS UPSLOPE INTO THE CENTRAL AND WESTERN
MOUNTAINS FOR THE ENTIRE NIGHT AND INTO SAT MORNING. THUS...THE
CLOUDS WILL MOST LIKELY LOWER AS THE LITTLE MIXING IN PLACE THIS
AFTN/EVENING GOES AWAY. EXPECT SOME DRIZZLE OR EVEN LIGHT SHOWERS
TO LINGER THROUGH THE NIGHT. COVERAGE AND INTENSITY ARE EXPECTED
TO BE ISOLD/SCT AND VERY LIGHT...SO WILL JUST CALL FOR AREAS OF
DZ AND FG AT MOST PLACES...ESP THE HILL TOPS. MINS WILL HOLD
WITHIN 5 DEGS OF 60F. MINOR LLVL RIDGING BUILDING DOWN FROM NY
STATE WILL ASSIST THE DAYTIME MIXING ON SAT IN EATING AWAY AT THE
STRATUS FROM THE OUTSIDE INWARD. WILL KEEP IT VERY CLOUDY IN THE
LAURELS AND CENTRAL MTS THROUGH THE ENTIRE DAY WITH HIGH RH KEPT
IN BY THE MDLS FOR THE LAYER BELOW 10KFT IN THE AM - AND MIXING
FROM BELOW HELPING TO LIFT THE LAYER TO A BASE OF 4-5KFT BY THE
END OF THE DAY. WILL MENTION DZ OR SCT SHRA IN THE MORNING FOR
THE CENTRAL MTS...AND FOR MOST OF THE DAY IN THE LAURELS.
ELSEWHERE...THE SKIES SHOULD SHOW SIGNIFICANT BREAKS IN THE AFTN.
BUT RIDGING WILL KEEP IT STABLE ENOUGH TO PRECLUDE MENTIONS OF
SHOWERS IN THE AFTN. TEMPS WILL CREEP CLOSER TO NORMAL MAXES ON
SAT WITH THE SLOWLY ERODING/THINNING CLOUDS. WILL MAKE IT MILDER
IN THE EAST WHERE CLOUDS HAVE THE BEST CHANCE OF MELTING AWAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE LONG TERM BEGINS WITH REGION UNDER UPPER-LEVEL NORTHWESTERLY
FLOW...WITH WEAK EMBEDDED DISTURBANCES. ALTHOUGH MUCH OF SUNDAY
AND MONDAY WILL BE PARTLY TO MOSTLY SUNNY AND DRY...THERE IS A
CHANCE FOR A MAINLY AFTN/EVE SHOWER OR THUNDERSTORM EACH DAY.
A SHARPER UPPER-LEVEL TROUGH WILL DIG INTO THE NORTHEASTERN
UNITED STATES ON TUESDAY...PUSHING A COLD FRONT ACROSS THE
COMMONWEALTH. THIS FRONT WILL BE ACCOMPANIED BY A CHC OF
SHRA/TSRA...ALTHOUGH EVEN TUES SHOULD FEATURE AT LEAST PARTIAL
SUNSHINE.
WEDNESDAY SHOULD BE A BIT COOLER AND DRIER AS THE FRONT SAGS JUST
TO OUR SOUTH AND STALLS. THE MODELS ARE HINTING THAT THE FRONT
WILL LIFT BACK NORTHWARD INTO THE REGION LATE IN THE
WEEK...BRINGING A RETURN OF UNSETTLED WEATHER.
TEMPERATURES WILL RISE TO ABOVE-NORMAL LEVELS MONDAY AND TUESDAY
PRIOR TO THE FRONTAL PASSAGE...BEFORE RETURNING CLOSER TO NORMAL
FOR THE MIDDLE TO LATTER PART OF THE WEEK.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
SLOW MOVING LOW PRES SYSTEM PASSING SOUTH OF PA TONIGHT WILL BRING
LOW CIGS AND OCNL RAIN/DRIZZLE TO CENTRAL PA THIS EVENING. A RIDGE OF
HIGH PRES OVR THE GRT LKS WILL PUSH SOUTHEAST TONIGHT...BRINGING
IMPROVING CONDS ACROSS THE SUSQ VALLEY INCLUDING IPT AND POSSIBLY
MDT/LNS LATE TONIGHT. HOWEVER...MOIST EASTERLY FLOW ASCENDING THE
HIGHER TERRAIN OF CENTRAL PA WILL LIKELY CAUSE IFR CIGS TO
PERSIST FROM BFD SOUTHWARD THRU UNV...AOO AND JST.
SLOW IMPROVEMENT TO GENERALLY MVFR CONDITIONS OVR THE CENTRAL MTNS SAT
AND VFR SUSQ VALLEY. CONTINUED IMPROVEMENT IS POSSIBLE SAT
NIGHT...BUT KJST MAY STAY IFR/MVFR INTO SUNDAY MORNING.
OUTLOOK...
MON-WED...MAINLY VFR...SCT PM TSTMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR PAZ024>026-
033>036.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...EVANEGO
AVIATION...DANGELO/FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
323 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN DRAPED ACROSS SOUTH CENTRAL
PENNSYLVANIA INTO THE NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD SOUTH ACROSS THE AREA SUNDAY AND MONDAY. TEMPERATURES FOR
MUCH OF NEXT WEEK WILL RETURN TO NEAR...OR SLIGHTLY ABOVE NORMAL.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
TSRA HAVE FORMED OVER SWRN PA AND ARE MOVING INTO THE LAURELS.
THIS AREA HAS BEEN PINPOINTED BY THE NAM AND RUC FOR THE PAST FEW
RUNS TO RECEIVE THE HEAVIEST RAINFALL OVER THE NEXT 6-9 HOURS.
BEST LLVL CONVERGENCE EXISTS THERE WITH FRONT INCHING SOUTHWARD.
SLIM BREAKS IN THE CLOUDS OVER SWRN PA HAVE ALLOW THE STABILITY TO
DROP AND CAPES TO CLIMB THE NAM HAS BEEN HANDLING THIS SITUATION
WELL WITH THE 06 AND 12Z RUNS. SINCE THEY HAVE HAD SIMILAR 1 TO
1.5 INCH AMOUNTS OF RAIN OVER THE PAST 36 HRS IN THE
LAURELS...HAVE EXPANDED THE FFA WESTWARD. CANCELLED THE FFA OVER
THE SERN COS - STABILITY IS HIGHER IN THE SE...BUT 0.5 TO 1 INCH
AMOUNTS ARE STILL POSSIBLE THERE THROUGH SUNSET. THESE AMOUNTS
SHOULD NOT BE ENOUGH TO CAUSE FLASH FLOODING IN THE SE. THE
STORMS IN THE SWRN COS WILL MOST LIKELY EXPAND AND SHOULD DROP
SLOWLY TO THE E/SE THIS EVENING...TAPERING OFF BY MIDNIGHT.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
LOW LEVEL FLOW REMAINS UPSLOPE INTO THE CENTRAL AND WESTERN
MOUNTAINS FOR THE ENTIRE NIGHT AND INTO SAT MORNING. THUS...THE
CLOUDS WILL MOST LIKELY LOWER AS THE LITTLE MIXING IN PLACE THIS
AFTN/EVENING GOES AWAY. EXPECT SOME DRIZZLE OR EVEN LIGHT SHOWERS
TO LINGER THROUGH THE NIGHT. COVERAGE AND INTENSITY ARE EXPECTED
TO BE ISOLD/SCT AND VERY LIGHT...SO WILL JUST CALL FOR AREAS OF
DZ AND FG AT MOST PLACES...ESP THE HILL TOPS. MINS WILL HOLD
WITHIN 5 DEGS OF 60F. MINOR LLVL RIDGING BUILDING DOWN FROM NY
STATE WILL ASSIST THE DAYTIME MIXING ON SAT IN EATING AWAY AT THE
STRATUS FROM THE OUTSIDE INWARD. WILL KEEP IT VERY CLOUDY IN THE
LAURELS AND CENTRAL MTS THROUGH THE ENTIRE DAY WITH HIGH RH KEPT
IN BY THE MDLS FOR THE LAYER BELOW 10KFT IN THE AM - AND MIXING
FROM BELOW HELPING TO LIFT THE LAYER TO A BASE OF 4-5KFT BY THE
END OF THE DAY. WILL MENTION DZ OR SCT SHRA IN THE MORNING FOR
THE CENTRAL MTS...AND FOR MOST OF THE DAY IN THE LAURELS.
ELSEWHERE...THE SKIES SHOULD SHOW SIGNIFICANT BREAKS IN THE AFTN.
BUT RIDGING WILL KEEP IT STABLE ENOUGH TO PRECLUDE MENTIONS OF
SHOWERS IN THE AFTN. TEMPS WILL CREEP CLOSER TO NORMAL MAXES ON
SAT WITH THE SLOWLY ERODING/THINNING CLOUDS. WILL MAKE IT MILDER
IN THE EAST WHERE CLOUDS HAVE THE BEST CHANCE OF MELTING AWAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE LONG TERM BEGINS WITH REGION UNDER UPPER-LEVEL NORTHWESTERLY
FLOW...WITH WEAK EMBEDDED DISTURBANCES. ALTHOUGH MUCH OF SUNDAY
AND MONDAY WILL BE PARTLY TO MOSTLY SUNNY AND DRY...THERE IS A
CHANCE FOR A MAINLY AFTN/EVE SHOWER OR THUNDERSTORM EACH DAY.
A SHARPER UPPER-LEVEL TROUGH WILL DIG INTO THE NORTHEASTERN
UNITED STATES ON TUESDAY...PUSHING A COLD FRONT ACROSS THE
COMMONWEALTH. THIS FRONT WILL BE ACCOMPANIED BY A CHC OF
SHRA/TSRA...ALTHOUGH EVEN TUES SHOULD FEATURE AT LEAST PARTIAL
SUNSHINE.
WEDNESDAY SHOULD BE A BIT COOLER AND DRIER AS THE FRONT SAGS JUST
TO OUR SOUTH AND STALLS. THE MODELS ARE HINTING THAT THE FRONT
WILL LIFT BACK NORTHWARD INTO THE REGION LATE IN THE
WEEK...BRINGING A RETURN OF UNSETTLED WEATHER.
TEMPERATURES WILL RISE TO ABOVE-NORMAL LEVELS MONDAY AND TUESDAY
PRIOR TO THE FRONTAL PASSAGE...BEFORE RETURNING CLOSER TO NORMAL
FOR THE MIDDLE TO LATTER PART OF THE WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
FRONTAL SYSTEM ACROSS CENTRAL PA WILL CONTINUE TO SAG SLOWLY
SOUTHWARD THIS EVENING. CONVECTION/THUNDER CURRENTLY OVER THE SW
WILL AFFECT KJST/KAOO THROUGH 02Z/03Z...BUT DIMINISH WITH LOSS OF
HEATING AS WELL AS THE SLOW SAG OF THE FRONT. ELSEWHERE...ONLY
ISOLD/SCT SHRA ARE EXPECTED AS A SHORT WAVE TROUGH SLIDES ACROSS
THE NRN TIER AND WEAK CONVERGENCE/UPSLOPE EXISTS IN THE LLVLS.
THE ENTIRE AREA WILL BE STUCK IN MAINLY IFR OR LOW-END MVFR CLOUDS
AND SCT SHRA OR DZ THROUGH THE WHOLE NIGHT. EXPECT LITTLE CHANGE
IN THE CIGS AND VSBYS TONIGHT...WITH SLIGHT IMPROVEMENT TO
GENERALLY MVFR CONDITIONS IN THE WEST SAT AND VFR EAST. CONTINUED
IMPROVEMENT IS POSSIBLE SAT NIGHT...BUT KJST MAY STAY IFR/MVFR
INTO SUNDAY MORNING.
OUTLOOK...
MON-WED...MAINLY VFR...SCT PM TSTMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR PAZ024>026-
033>036.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...EVANEGO
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
249 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN DRAPED ACROSS SOUTH CENTRAL
PENNSYLVANIA INTO THE NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD SOUTH ACROSS THE AREA SUNDAY AND MONDAY. TEMPERATURES FOR
MUCH OF NEXT WEEK WILL RETURN TO NEAR...OR SLIGHTLY ABOVE NORMAL.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
TSRA HAVE FORMED OVER SWRN PA AND ARE MOVING INTO THE LAURELS.
THIS AREA HAS BEEN PINPOINTED BY THE NAM AND RUC FOR THE PAST FEW
RUNS TO RECEIVE THE HEAVIEST RAINFALL OVER THE NEXT 6-9 HOURS.
BEST LLVL CONVERGENCE EXISTS THERE WITH FRONT INCHING SOUTHWARD.
SLIM BREAKS IN THE CLOUDS OVER SWRN PA HAVE ALLOW THE STABILITY TO
DROP AND CAPES TO CLIMB THE NAM HAS BEEN HANDLING THIS SITUATION
WELL WITH THE 06 AND 12Z RUNS. SINCE THEY HAVE HAD SIMILAR 1 TO
1.5 INCH AMOUNTS OF RAIN OVER THE PAST 36 HRS IN THE
LAURELS...HAVE EXPANDED THE FFA WESTWARD. CANCELLED THE FFA OVER
THE SERN COS - STABILITY IS HIGHER IN THE SE...BUT 0.5 TO 1 INCH
AMOUNTS ARE STILL POSSIBLE THERE THROUGH SUNSET. THESE AMOUNTS
SHOULD NOT BE ENOUGH TO CAUSE FLASH FLOODING IN THE SE. THE
STORMS IN THE SWRN COS WILL MOST LIKELY EXPAND AND SHOULD DROP
SLOWLY TO THE E/SE THIS EVENING...TAPERING OFF BY MIDNIGHT.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
LOW LEVEL FLOW REMAINS UPSLOPE INTO THE CENTRAL AND WESTERN
MOUNTAINS FOR THE ENTIRE NIGHT AND INTO SAT MORNING. THUS...THE
CLOUDS WILL MOST LIKELY LOWER AS THE LITTLE MIXING IN PLACE THIS
AFTN/EVENING GOES AWAY. EXPECT SOME DRIZZLE OR EVEN LIGHT SHOWERS
TO LINGER THROUGH THE NIGHT. COVERAGE AND INTENSITY ARE EXPECTED
TO BE ISOLD/SCT AND VERY LIGHT...SO WILL JUST CALL FOR AREAS OF
DZ AND FG AT MOST PLACES...ESP THE HILL TOPS. MINS WILL HOLD
WITHIN 5 DEGS OF 60F. MINOR LLVL RIDGING BUILDING DOWN FROM NY
STATE WILL ASSIST THE DAYTIME MIXING ON SAT IN EATING AWAY AT THE
STRATUS FROM THE OUTSIDE INWARD. WILL KEEP IT VERY CLOUDY IN THE
LAURELS AND CENTRAL MTS THROUGH THE ENTIRE DAY WITH HIGH RH KEPT
IN BY THE MDLS FOR THE LAYER BELOW 10KFT IN THE AM - AND MIXING
FROM BELOW HELPING TO LIFT THE LAYER TO A BASE OF 4-5KFT BY THE
END OF THE DAY. WILL MENTION DZ OR SCT SHRA IN THE MORNING FOR
THE CENTRAL MTS...AND FOR MOST OF THE DAY IN THE LAURELS.
ELSEWHERE...THE SKIES SHOULD SHOW SIGNIFICANT BREAKS IN THE AFTN.
BUT RIDGING WILL KEEP IT STABLE ENOUGH TO PRECLUDE MENTIONS OF
SHOWERS IN THE AFTN. TEMPS WILL CREEP CLOSER TO NORMAL MAXES ON
SAT WITH THE SLOWLY ERODING/THINNING CLOUDS. WILL MAKE IT MILDER
IN THE EAST WHERE CLOUDS HAVE THE BEST CHANCE OF MELTING AWAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
POSITIVE TILT...SFC AND UPPER LEVEL RIDGE WILL NOSE INTO THE REGION
FROM THE WEST SATURDAY NIGHT AND SUNDAY BRINGING PARTIAL
CLEARING...LIGHT WINDS...AND DRY WEATHER.
HIGH TEMPS SUNDAY WILL REBOUND BACK TO NEAR OR JUST SLIGHTLY BELOW
NORMAL. WILL STAY WITH CONTINUITY AND INCLUDE JUST A FEW ISOLATED
SHRA/TSRA AFTER 18Z SUNDAY. HOWEVER...COVERAGE SHOULD BE QUITE
SPARSE AS MID LEVEL LAPSE RATES WILL BE AOB 6C/KM.
THE SERN CANADA AND NE U.S. UPPER TROUGH AMPLIFIES THROUGH THE
MIDWEEK PERIOD. SEVERAL FAST MOVING...ALBEIT RATHER FLAT SHORTWAVES
WILL RACE SOUTHEAST /WITH SOME OBVIOUS TIMING UNCERTAINTY/ AND
TRIGGER SOME MAINLY AFTERNOON/EARLY EVENING SCTD SHOWERS AND TSRA
MONDAY AND TUESDAY.
HEIGHTS BEGIN TO RISE WEDNESDAY ACCOMPANIED BY AN AREA OF HIGH
PRESSURE AT THE SFC DRIFTING OVERHEAD. KEPT IT DRY WITH POPS ONLY
AROUND 10 PERCENT WEDNESDAY. WARMER AIR WILL PUSH EAST INTO THE
REGION AT THE SFC AND ALOFT LATER IN THE WEEK BRINGING A CHANCE FOR
A FEW SHOWERS AND ISOLATED TO SCATTERED TSRA.
TEMPS FOR MUCH OF NEXT WEEK SHOULD BE NEAR TO SLIGHTLY ABOVE NORMAL
WITH MODERATE DEWPOINTS GENERALLY IN THE U50S NORTH...TO MID 60S IN
THE SOUTH.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
FRONTAL SYSTEM ACROSS CENTRAL PA WILL CONTINUE TO SAG SLOWLY
SOUTHWARD THIS EVENING. CONVECTION/THUNDER CURRENTLY OVER THE SW
WILL AFFECT KJST/KAOO THROUGH 02Z/03Z...BUT DIMINISH WITH LOSS OF
HEATING AS WELL AS THE SLOW SAG OF THE FRONT. ELSEWHERE...ONLY
ISOLD/SCT SHRA ARE EXPECTED AS A SHORT WAVE TROUGH SLIDES ACROSS
THE NRN TIER AND WEAK CONVERGENCE/UPSLOPE EXISTS IN THE LLVLS.
THE ENTIRE AREA WILL BE STUCK IN MAINLY IFR OR LOW-END MVFR CLOUDS
AND SCT SHRA OR DZ THROUGH THE WHOLE NIGHT. EXPECT LITTLE CHANGE
IN THE CIGS AND VSBYS TONIGHT...WITH SLIGHT IMPROVEMENT TO
GENERALLY MVFR CONDITIONS IN THE WEST SAT AND VFR EAST. CONTINUED
IMPROVEMENT IS POSSIBLE SAT NIGHT...BUT KJST MAY STAY IFR/MVFR
INTO SUNDAY MORNING.
OUTLOOK...
MON-WED...MAINLY VFR...SCT PM TSTMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR PAZ024>026-
033>036.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
315 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND ARRIVE ON
SATURDAY. THE FRONT IS EXPECTED TO STALL OVER THE AREA THROUGH THE
WEEKEND BEFORE DISSIPATING MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THE AFTERNOON... ANTICIPATE THE FOCUS OF
STRONGEST CONVECTIVE STORMS WILL EXTEND FROM UPSTATE SC NORTHEAST
ITNO THE SOUTHERN PIEDMONT OF NC. THAT IS ALIGNED WITH RAP SBCAPE
MAXIMUM OF 3000+ J/KG. EFFECTIVE SHEAR IS HIGH ENOUGH OVER PORTIONS
OF THE MOUNTAINS TO SUGGEST SOME ORGANIZATION TO THE
THUNDERSTORMS... BUT THAT AREA IS WEST OF THE MOST UNSTABLE AIR.
PLUS... THE MID-LEVEL VORTICITY MAXIMUM AND BEST VORTICITY ADVECTION
APPEARS TO BE MOVING OUT OVER THE PIEDMONT AS SHORT WAVE TROUGH
ALOFT TRAVELS EASTWARD. SHEAR EAST OF MOUNTAINS NOT PARTICULARLY
IMPRESSIVE AND DOWNDRAFT CAPE IS ONLY AROUND 500 J/KG... SO PULSE
NATURE OF STORMS LIKELY TO PREDOMINATE WITH POSSIBILITY OF SOME
MULTICELL CLUSTERS GETTING TOGETHER.
OTHWERWISE... MODELS IN PRETTY GOOD AGREEMENT REGARDING EVOLUTION OF
MID AND UPPER LEVEL FEATURES THROUGH DAYTIME SATURDAY. AT 500 MB...
LARGE RIDGE PERSISTS OVER WESTERN U.S. WITH BERMUDA HIGH OVER
ATLANTIC. 500 MB TROUGH EXTENDING DOWN EAST COAST INTO OUR CWA
PERSISTS THROUGH SATURDAY... BUT IT WITHDRAWS SLOWLY TO THE NORTH
LEAVING A SHEAR AXIS BEHIND. SHORT WAVE TROUGH CROSSING CWA THIS
AFTERNOON AND THIS EVENING WILL MAINTAIN SURFACE LOW ON FRONTAL
BOUNDARY ACROSS MID-ATLANTIC REGION. LOW WILL BE OFFSHORE SATURDAY
MORNING AND CONTINUE MOVING EAST THEREAFTER. BERMUDA HIGH BUILDS
SLOWLY WESTWARD AS 500 MB HEIGHTS INCREASE JUST A BIT. THIS WILL MAKE
SOUTHWARD MOVEMENT OF FRONTAL BOUNDARY VERY DIFFICULT TO MAINTAIN.
MOIST SOUTHWEST FLOW AHEAD OF THE FRONT ON WEST SIDE OF BERMUDA HIGH
WORKS IN COMBINATION WITH THE WEAK UPPER-LEVEL TROUGH/SHEAR AXIS TO
CONTINUE A MOIST SOUTHWEST FLOW INTO OUR AREA. FORECASTS FOR
OVERNIGHT AND SATURDAY ACCORDINGLY WILL CARRY POPS FOR SHOWERS AND
THUNDERSTORMS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 230 PM EDT FRIDAY...AN UPPER TROUGH AXIS WILL REMAIN ALONG THE
EAST COAST FROM SATURDAY NIGHT THROUGH MONDAY...WHILE A RIDGE
REMAINS OVER THE PLAINS. A WEAKENING...STALLED SURFACE FRONT WILL
REMAIN OVER OUR AREA THROUGH MONDAY. ALTHOUGH THERE DOES NOT APPEAR
TO BE MUCH ISENTROPIC UPGLIDE OVER THE BOUNDARY...SHORTWAVES MOVING
INTO THE UPPER TROUGH AND OVER THE VICINITY OF THE FRONT WILL
SUPPORT PRECIPITATION THROUGH THE PERIOD...MAXIMIZED WITH GREATER
INSTABILITY DURING DAYLIGHT HOURS. WITHOUT A STRONG LIFTING
MECHANISM...PRECIPITATION AMOUNTS ARE EXPECTED TO BE MODERATE...BUT
SEVERAL DAYS OF RAIN COULD LEAD TO SOME LOCALIZED HYDROLOGICAL
PROBLEMS WITH TIME. MINIMUM TEMPERATURES WILL BE SLIGHTLY ABOVE
NORMAL...AND MAXIMUM TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 145 PM FRIDAY...THE CWFA WILL BE IN AN AREA BETWEEN RIDGING TO
THE SOUTH AND WEST AND NW TO SE ORIENTED NRN STREAM FLOW TO THE
NORTH. THE FLOW WILL BE CLOSE ENUF THAT WE SHUD SEE SOME EFFECT FROM
A SERIES OF WEAK SHORT WAVES MOVING THRU THE FLOW. AT THE SFC...A
BACK DOOR COLD FRONT WILL APPROACH THE AREA BUT STALL TO OUR NORTH.
A SERIES OF LOW PRESSURE WAVES WILL MOVE WEST ALONG THE FRONT. OVER
OUR CWFA...A LEE TROF AND COPIOUS LOW LEVEL MOISTURE WILL REMAIN IN
PLACE THRU THE PERIOD. THIS SHUD LEAD TO GENERALLY SCT DIURNAL
CONVECTION EACH DAY. LOWS WILL BE NEARLY STEADY AROUND 5 DEGREES
ABOVE NORMAL. HIGHS START OUT NEARLY 5 DEGREES ABOVE NORMAL THEN
FALL A COUPLE OF DEGREES BY THE END OF THE PERIOD.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT... SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE IN THE
VICINITY OF THE TERMINAL THROUGH 00Z. THUNDERSTORMS WILL BE CAPABLE
OF STRONG AND GUSTY WIND AND SMALL HAIL. AFTER 02Z... CEILING 4-6 KT
FT LOWERING TO NEAR 2K FT AROUND 12Z. POSSIBILITY EXISTS OF
VISIBILITY NEAR 5 MI IN FOG AROUND SUNRISE. CONSIDERABLE CLOUDINESS
WILL MAKE RADIATIONAL COOLING DIFFICULT... SO VISILITY RESTRICTION
NOT CURRENTLY IN TAF DUE TO UNCERTAINTY. EXCEPT NEAR
THUNDERSTORMS... SURFACE WIND WILL BE SOUTHWEST LESS THAN 10 KT.
REMAINDER TERMINALS... 4-6K FT BROKEN TO OVERCAST. VISIBILITY
UNRESTRICTED EXPECT VICINITY SCATTERED THUNDERSTORMS... MOST
NUMEROUS NEAR KAND... KGMU... AND KGSP. AFT 02Z... SHOWERS AND
THUNDERSTORMS BECOME MORE WIDELY SCATTERED. TOWARD SUNRISE... SOME
LOWER CEILING 2-4 KT FT AND POSSIBILITY OF VISIBILITY RESTRICTION IN
FOG... ESPECIALLY VICINITY KAVL.
OUTLOOK...AS A COLD FRONT STALLS OVER THE AREA...SCATTERED TO
NUMEROUS CONVECTIVE STORMS AND ASSOCIATED RESTRICTIONS WILL PERSIST
THROUGH THE WEEKEND. LATE NIGHT/MORNING FOG AND LOW STRATUS
PROBABILITIES WILL ALSO REMAIN FAIRLY HIGH...ESPECIALLY IN THE MTN
VALLEYS. THUNDERSTORMS WILL BECOME LESS NUMEROUS AS BERMUDA HIGH
BUILDS INTO THE REGION DURING THE FIRST PART OF THE 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...JAT
NEAR TERM...LGL
SHORT TERM...JAT
LONG TERM...RWH
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
151 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND ARRIVE ON
SATURDAY. THE FRONT IS EXPECTED TO STALL OVER THE AREA THROUGH THE
WEEKEND BEFORE DISSIPATING MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 130 PM EDT... CONVECTIVE STORMS ARE DEVELOPING RAPIDLY ACROSS
UPSTATE SOUTH CAROLINA INTO THE SOUTHERN PIEDMONT OF NORTH CAROLINA.
EXPECT CONVECTIVE WEATHER TO BE PRIMARY FEATURE THIS AFTERNOON. RAP
CAPES DISPLAY AN AXIS OF 3000 J/KG EXTENDING FROM SOUTH OF KGSP TO
VICINITY KCLT.
PREVIOUS DISCUSSION...
AT 1030 AM EDT... MORNING DATA CONTINUE TO INDICATE POTENTIAL FOR
THUNDERSTORMS DURING THE AFTERNOON AND EVENING... BUT CLOUDINESS
FROM OVERNIGHT MCS TO OUR WEST AND FRONT TO THE NORTH IS SPREADING
OVER MUCH OF THE CWA. CLOUDS COULD PUT A LITTLE BIT OF A DAMPER OR
DELAY ON CONVECTIVE INITIATION... BUT THERE WILL BE PLENTY OF
OPPORTUNITY FOR CLOUDS TO ERODE THUS ALLOWING BOUNDARY LAYER TO
COLLECT SOME WARMTH. IN THE VERY NEAR TERM... WILL DECREASE POPS
BUT INCREASE THEM TO CURRENT FORECAST VALUE BY MID TO LATE AFTERNOON.
AFTERNOON RAP CAPES ARE IN THE 1500 TO 3000 J/KG RANGE WITH AXIS OF
HIGHEST CAPE FROM APPROXIMALY KAND TO KCLT BY 17Z. NAM CAPES ARE A
LITTLE LOWER... GENERALLY 1000 TO 2000 J/KG... EXCEPT LESS THAN 1000
OVER MOUNTAINS. WIND PROFILES IDENTIFY VERY LITTLE SHEAR... SO PULSE
STORMS WITH LITTLE ORGANIZATION EXPECTED. QUITE POSSIBLE THAT SOME
MULTICELL CLUSTERS CAN DEVELOP... BUT RAP DCAPES ARE ONLY AROUND 500
J/KG SO THAT LOWERS CONFIDENCE A LITTLE THAT MAJOR COLD POOLS WILL
DEVELOP. HOWEVER... NAM MOVES AN AXIS OF DCAPE AROUND 1000 J/KG
ACROSS CWA FROM WEST TO EAST LATER TODAY. POTENTIAL FOR THAT FEATURE
WILL NEED TO BE MONITORED.
AS OF 605 AM EDT...MCS ACTIVITY HAS BEEN WEAKENING TO OUR WEST...BUT
IT IS STILL GENERATING QUITE A FEW CLOUD TO GROUND LIGHTNING STRIKES
OVER CENTRAL TENN AND NORTHERN ALABAMA. OVER THE PAST FEW
HOURS...THE ONLY SHOWER ACTIVITY WE HAVE SEEN HAS BEEN OVER THE FAR
WESTERN NC MTS...HOWEVER COVERAGE SHOULD BEGIN TO INCREASE LATER
THIS MORNING AS THINGS BEGIN TO HEAT UP AND THE FIRST UPPER
SHORTWAVE APPROACHES. TEMPS ARE HOLDING A BIT WARMER THAN
ANTICIPATED...SO I BUMPED UP THE MIN TEMPS A DEGREE OR 2.
PREVIOUS DISCUSSION...
A COLD FRONT WILL APPROACH FROM THE NORTH LATER TODAY...WHILE A PAIR
OF FAIRLY POTENT LOOKING H5 SHORTWAVES MOVE INTO THE BASE OF THE
TROUGH. WITH THE ATMOSPHERE REMAINING MOIST AND UNSTABLE...I KEEP
POPS AT LIKELY OVER MOST OF THE CWFA DURING THE LATE AFTERNOON AND
THRU THE LATE EVENING HOURS. CONDITIONS WILL BE SUFFICIENT FOR
SEVERE THUNDERSTORMS AGAIN...AND WITH UNIDIRECTIONAL SHEAR
PRESENT...SOME ORGANIZATION IS POSSIBLE...ESPECIALLY IN THE
PIEDMONT. WITH BETTER STEERING FLOW AND MOVING STORMS...FLOODING
SHOULD NOT BE AS MUCH OF A CONCERN...HOWEVER LOCALIZED...HIGH QPF
WILL BE POSSIBLE FROM TRAINING OR REPEATING CELLS. MAXIMUM
TEMPERATURES WILL BE NEAR NORMAL...AS LONG AS CLOUD COVER BREAKS
ENOUGH TO ALLOW SUFFICIENT HEATING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AT 230 PM EDT FRIDAY...AN UPPER TROUGH AXIS WILL REMAIN ALONG THE
EAST COAST FROM SATURDAY NIGHT THROUGH MONDAY...WHILE A RIDGE
REMAINS OVER THE PLAINS. A WEAKENING...STALLED SURFACE FRONT WILL
REMAIN OVER OUR AREA THROUGH MONDAY. ALTHOUGH THERE DOES NOT APPEAR
TO BE MUCH ISENTROPIC UPGLIDE OVER THE BOUNDARY...SHORTWAVES MOVING
INTO THE UPPER TROUGH AND OVER THE VICINITY OF THE FRONT WILL
SUPPORT PRECIPITATION THROUGH THE PERIOD...MAXIMIZED WITH GREATER
INSTABILITY DURING DAYLIGHT HOURS. WITHOUT A STRONG LIFTING
MECHANISM...PRECIPITATION AMOUNTS ARE EXPECTED TO BE MODERATE...BUT
SEVERAL DAYS OF RAIN COULD LEAD TO SOME LOCALIZED HYDROLOGICAL
PROBLEMS WITH TIME. MINIMUM TEMPERATURES WILL BE SLIGHTLY ABOVE
NORMAL...AND MAXIMUM TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 145 PM FRIDAY...THE CWFA WILL BE IN AN AREA BETWEEN RIDGING TO
THE SOUTH AND WEST AND NW TO SE ORIENTED NRN STREAM FLOW TO THE
NORTH. THE FLOW WILL BE CLOSE ENUF THAT WE SHUD SEE SOME EFFECT FROM
A SERIES OF WEAK SHORT WAVES MOVING THRU THE FLOW. AT THE SFC...A
BACK DOOR COLD FRONT WILL APPROACH THE AREA BUT STALL TO OUR NORTH.
A SERIES OF LOW PRESSURE WAVES WILL MOVE WEST ALONG THE FRONT. OVER
OUR CWFA...A LEE TROF AND COPIOUS LOW LEVEL MOISTURE WILL REMAIN IN
PLACE THRU THE PERIOD. THIS SHUD LEAD TO GENERALLY SCT DIURNAL
CONVECTION EACH DAY. LOWS WILL BE NEARLY STEADY AROUND 5 DEGREES
ABOVE NORMAL. HIGHS START OUT NEARLY 5 DEGREES ABOVE NORMAL THEN
FALL A COUPLE OF DEGREES BY THE END OF THE PERIOD.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT... UPDATED 18Z TAF INCLUDES TEMPO FOR THUNDERSTORMS DURING
AFTERNOON. OTHERWISE... CONVECTIVE CLOUD BASES 4-5K FT. SURFACE WIND
WILL BE PREDOMINANTLY FROM SOUTHWEST AT LESS THAN 10 KT... BUT
STRONG AND GUSTY VICINITY THUNDERSTORMS. THUNDERSTORMS WILL BE
CAPABLE OF PRODUCING SMALL HAIL. OVERNIGHT... EXPECT CLOUD BASES
4-5K FT CONTINUING BUT LOWERING TO 2-4 KT FT.
REMAINDER TAF SITES... SCATTERED THUNDERSTORMS DURING AFTERNOON WILL
PRODUCE CEILING AND VISIBILITY RESTRICTIONS. EXCEPT VARIABLE WIND AT
KAVL SOUTHWEST WIND LESS THAN 10 KT EXCEPT STRONG AND GUSTY NEAR
THUNDERSTORMS. THUNDERSTORMS CAPABLE OF PRODUCING SMALL HAIL.
OVERNIGHT... EXPECT CLOUD BASES 3-5K FT WITH SOME VISIBILITY
RESTRICTIONS IN FOG TOWARD SUNRISE... SPECIALLY VICINITY KAVL.
OUTLOOK...AS A COLD FRONT STALLS OVER THE AREA...SCATTERED TO
NUMEROUS (MAINLY DIURNAL) CONVECTION AND ASSOCIATED RESTRICTIONS
WILL PERSIST THROUGH THE WEEKEND. LATE NIGHT/MORNING FOG AND LOW
STRATUS PROBABILITIES WILL ALSO REMAIN FAIRLY HIGH...ESPECIALLY IN
THE MTN VALLEYS.
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...JAT
NEAR TERM...LGL
SHORT TERM...JAT
LONG TERM...RWH
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1037 AM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND ARRIVE ON
SATURDAY. THE FRONT IS EXPECTED TO STALL OVER THE AREA THROUGH THE
WEEKEND BEFORE DISSIPATING MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1030 AM EDT... MORNING DATA CONTINUE TO INDICATE POTENTIAL FOR
THUNDERSTORMS DURING THE AFTERNOON AND EVENING... BUT CLOUDINESS
FROM OVERNIGHT MCS TO OUR WEST AND FRONT TO THE NORTH IS SPREADING
OVER MUCH OF THE CWA. CLOUDS COULD PUT A LITTLE BIT OF A DAMPER OR
DELAY ON CONVECTIVE INITIATION... BUT THERE WILL BE PLENTY OF
OPPORTUNITY FOR CLOUDS TO ERODE THUS ALLOWING BOUNDARY LAYER TO
COLLECT SOME WARMTH. IN THE VERY NEAR TERM... WILL DECREASE POPS
BUT INCREASE THEM TO CURRENT FORECAST VALUE BY MID TO LATE AFTERNOON.
AFTERNOON RAP CAPES ARE IN THE 1500 TO 3000 J/KG RANGE WITH AXIS OF
HIGHEST CAPE FROM APPROXIMALY KAND TO KCLT BY 17Z. NAM CAPES ARE A
LITTLE LOWER... GENERALLY 1000 TO 2000 J/KG... EXCEPT LESS THAN 1000
OVER MOUNTAINS. WIND PROFILES IDENTIFY VERY LITTLE SHEAR... SO PULSE
STORMS WITH LITTLE ORGANIZATION EXPECTED. QUITE POSSIBLE THAT SOME
MULTICELL CLUSTERS CAN DEVELOP... BUT RAP DCAPES ARE ONLY AROUND 500
J/KG SO THAT LOWERS CONFIDENCE A LITTLE THAT MAJOR COLD POOLS WILL
DEVELOP. HOWEVER... NAM MOVES AN AXIS OF DCAPE AROUND 1000 J/KG
ACROSS CWA FROM WEST TO EAST LATER TODAY. POTENTIAL FOR THAT FEATURE
WILL NEED TO BE MONITORED.
PREVIOUS DISCUSSION...
AS OF 605 AM EDT...MCS ACTIVITY HAS BEEN WEAKENING TO OUR WEST...BUT
IT IS STILL GENERATING QUITE A FEW CLOUD TO GROUND LIGHTNING STRIKES
OVER CENTRAL TENN AND NORTHERN ALABAMA. OVER THE PAST FEW
HOURS...THE ONLY SHOWER ACTIVITY WE HAVE SEEN HAS BEEN OVER THE FAR
WESTERN NC MTS...HOWEVER COVERAGE SHOULD BEGIN TO INCREASE LATER
THIS MORNING AS THINGS BEGIN TO HEAT UP AND THE FIRST UPPER
SHORTWAVE APPROACHES. TEMPS ARE HOLDING A BIT WARMER THAN
ANTICIPATED...SO I BUMPED UP THE MIN TEMPS A DEGREE OR 2.
PREVIOUS DISCUSSION...
A COLD FRONT WILL APPROACH FROM THE NORTH LATER TODAY...WHILE A PAIR
OF FAIRLY POTENT LOOKING H5 SHORTWAVES MOVE INTO THE BASE OF THE
TROUGH. WITH THE ATMOSPHERE REMAINING MOIST AND UNSTABLE...I KEEP
POPS AT LIKELY OVER MOST OF THE CWFA DURING THE LATE AFTERNOON AND
THRU THE LATE EVENING HOURS. CONDITIONS WILL BE SUFFICIENT FOR
SEVERE THUNDERSTORMS AGAIN...AND WITH UNIDIRECTIONAL SHEAR
PRESENT...SOME ORGANIZATION IS POSSIBLE...ESPECIALLY IN THE
PIEDMONT. WITH BETTER STEERING FLOW AND MOVING STORMS...FLOODING
SHOULD NOT BE AS MUCH OF A CONCERN...HOWEVER LOCALIZED...HIGH QPF
WILL BE POSSIBLE FROM TRAINING OR REPEATING CELLS. MAXIMUM
TEMPERATURES WILL BE NEAR NORMAL...AS LONG AS CLOUD COVER BREAKS
ENOUGH TO ALLOW SUFFICIENT HEATING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 310 AM FRIDAY...AN UPPER TROF WITH A SERIES OF EMBEDDED
SHORTWAVES REMAINS OVER THE REGION SAT AS THE SFC BOUNDARY STALLS
ACROSS THE AREA. THIS COMBINED WITH RIGHT ENTRANCE REGION OF THE
UPPER JET OVER THE CWA WILL PROVIDE ENOUGH SYNOPTIC SCALE FORCING
AND UPPER DIVERGENCE FOR LIKELY CONVECTION SAT...WITH SCT CONVECTION
LINGERING THRU THE EVE. DUE TO LOWER HEIGHTS...INCREASED CLOUDS AND
SHWRS...HIGH TEMPS WILL BE BELOW AVG SAT WITH LOWS AROUND AVG SAT
NIGHT. THE SHORT WAVE MOVES E OF THE REGION SUN BUT A WEAKNESS
BETWEEN A RIDGE TO THE W AND ONE TO THE E WILL LEAVE A SHEAR AXIS
OVER THE AREA. IT STILL APPEARS THE FRONT WILL BEGIN TO WASH OUT BUT
A WEAK BOUNDARY IS EXPECTED TO LINGER ACROSS THE AREA. THIS SHOULD
BE ENOUGH FOCUS FOR AT LEAST SCT CONVECTION SUN AFTN-EVE. LOOK FOR
TEMPS WITHIN A DEG OR SO OF AVG.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 310 AM FRIDAY...A WEAK TROF WILL REMAIN OVER THE REGION
MON...THEN THE AXIS WILL TRANSITION E THRU THE WEEK. AS AN UPPER
RIDGE BEGINS TO BUILD IN FROM THE W TUE-WED...A SERIES OF WEAK SHORT
WAVES WILL MOVE OVER THE AREA. A LEE TROF IS EXPECTED TO REMAIN
ACROSS THE PIEDMONT WITH ABOVE AVG LOW LEVEL MOISTURE LINGERING OVER
THE AREA...LEADING TO DIURNALLY ENHANCED CONVECTION EACH DAY. EXPECT
NEAR TO SLIGHTLY ABOVE AVG TEMPS MON...ABOVE AVG TUE-THU.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT... BOUNDARY LAYER HEATING AND MIXING GRADUALLY ELIMINATING
STRATUS CEILING NEAR 15 HND FT BUT COULD LINGER VICINITY TERMINAL
UNTIL APPROXIMATELY 16Z. SURFACE WIND WILL BE SOUTHWEST 10 KT OR LESS.
LAYERS OF MID AND HIGH CLOUDS FROM REMNANTS OF CONVECTION TO THE
WEST AND FRONT TO THE NORTH WILL CONTINUE TO DRIFT OVER THE AREA.
CONVECTIVE CLOUDS WITH BASES AROUND 5K FT WILL BE THE PREDOMINANT
LOWER CLOUD DURING THE AFTERNOON AND INTO THE EVENING. AFTER 18Z...
CEILING AND VISIBILITY RESTRICTIONS WILL EXIST IN THUNDERSTORMS...
POSSIBLY ACCOMPANIED BY SMALL HAIL AND STRONG AND GUSTY WIND
VARIABLE IN DIRECTION. LOW STRATUS AND FOG COULD OCCUR VICINITY
AIRFIELD SATURDAY MORNING.
REMAINDER TAF SITES... MID AND HIGH CLOUD LAYERS PRODUCED BY
CONVECTIVE STORMS TO THE WEST AND APPROACHING WEAK COLD FRONT WILL
DRIFT ACROSS AREA. DURING AFTERNOON PREDOMINANT LOW CLOUD WILL BE
BASES OF CONVECTIVE CLOUDS AT 4-5K FT. CEILING AND VISIBILITY
RESTRICTIONS WILL EXIST IN THUNDERSTORMS... POSSIBLY ACCOMPANIED BY
SMALL HAIL AND STRONG AND GUSTY WIND. THUNDERSTORMS LIKELY TO
CONTINUE INTO THE NIGHT. LOW AND STRATUS AND FOG CLOUD OCCUR
SATURDAY MORNING... PARTICULARLY AT SITES THAT HAVE RAINFALL.
OUTLOOK...AS A COLD FRONT STALLS OVER THE AREA...SCATTERED TO
NUMEROUS (MAINLY DIURNAL) CONVECTION AND ASSOCIATED RESTRICTIONS
WILL PERSIST THROUGH THE WEEKEND. LATE NIGHT/MORNING FOG AND LOW
STRATUS PROBABILITIES WILL ALSO REMAIN FAIRLY HIGH...ESPECIALLY IN
THE MTN VALLEYS.
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...JAT
NEAR TERM...LGL
SHORT TERM...RB
LONG TERM...RB
AVIATION...JPT
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1255 PM CDT FRI JUL 20 2012
.DISCUSSION...
UPDATED FOR AVIATION.
&&
.PREV DISCUSSION... /ISSUED 1100 AM CDT FRI JUL 20 2012/
UPDATE...
CONDITIONS AT 11 AM HAVE WARMED INTO THE 90S WEST OF A LINE FROM
ROUGHLY DYERSBURG TO CLARKSDALE. FURTHER EAST...SOME INFLUENCE
FROM THE ROBUST THUNDERSTORM ACTIVITY IN MIDDLE TENNESSEE /CLOUDS
AND OUTFLOWS/ HAS TEMPERED TEMPERATURES A BIT IN THE 80S. THE
925MB THERMAL RIDGE HAS NOW CENTERED ITSELF ALONG A LINE FROM
OKLAHOMA CITY EAST TO MEMPHIS. AN ILL-DEFINED FRONT APPEARS TO BE
SITUATED OVER NRN MS WITH A FEW STORMS AHEAD OF IT OVER MONROE
COUNTY.
WILL LEAVE THE CURRENT HEADLINE CONFIGURATION IN PLACE...BUT THE
EASTERN COUNTIES WITHIN THE WARNING ARE MARGINAL GIVEN THE CURRENT
CLOUD COVER. NAM 925 MB TEMPS HAVE ALSO COME DOWN A COUPLE
DEGREES...SO REDUCED HIGHS BY A DEGREE OR TWO IN MOST PLACES.
STILL THINK HEAT INDICES OF 110F ARE OBTAINABLE OVER THE DELTA AND
NEAR I-40 IN SWRN TN.
MODELS ARE RELUCTANT TO DEVELOP ANYTHING SIGNIFICANT THIS
AFTERNOON...BUT THE HRRR DOES SHOW ISOLATED CELLS DEVELOPING LATE
THIS AFTERNOON OVER MOST OF THE AREA SO DID NOT FEEL I COULD
REMOVE POPS.
BORGHOFF
PREV DISCUSSION... /ISSUED 508 AM CDT FRI JUL 20 2012/
DISCUSSION...
TEMPERATURES ARE GENERALLY RUNNING 1-5 DEGREES WARMER THAN THEY
WERE 24 HOURS AGO...AND DEW POINTS ARE AROUND 2 DEGREES WARMER
WITH THE EXCEPTION OF NORTHEAST ARKANSAS WHERE SOME DRIER AIR IS
WORKING IN. 4 AM TEMPERATURES REMAIN IN THE LOW 80S AT MANY
LOCATIONS ACROSS THE MIDSOUTH THE WARMEST READINGS ARE IN THE
DELTA AREAS...INCLUDING THE MEMPHIS METRO AREA WITH THE COOLEST
READINGS IN NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER. A FEW SHOWERS DEVELOPED ALONG THE
TENNESSEE/MISSISSIPPI STATE LINE EARLIER THIS MORNING...BUT HAVE
NOW PRETTY MUCH DISSIPATED. MID AND HIGH CLOUDS OVERSPREAD MOST OF
THE MIDSOUTH HELPING TO LIMIT RADIATIONAL COOLING.
WE SHOULD SEE ANOTHER VERY HOT DAY TODAY DESPITE SOME CLOUD
COVER.AN EXCESSIVE HEAT WARNING HAS BEEN ISSUED FOR MUCH OF THE
AREA. TEMPERATURES WILL START A FEW DEGREES WARMER THAN YESTERDAY
AND WARM QUICKLY INTO THE 90S. CONVECTION WILL GET GOING FAIRLY
EARLY AND MAY PROVIDE SOME LOCALIZED RELIEF TO THE HEAT...BUT DO
NOT THINK COVERAGE...OR THE DURATION OF ANY PRECIPITATION WILL
LIMIT THE HEATING ON ANY LARGE SCALE. THE EXCEPTION MAY BE ACROSS
PORTIONS OF NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER WHERE STORMS ARE EXPECTED TO BE MOST WIDESPREAD.
AFTERNOON HIGHS WILL BE AT OR ABOVE 99 DEGREES ACROSS MOST OF THE
AREA...WITH THE EXCEPTION BEING THE SAME AREA MENTIONED ABOVE. THE
WARMEST READINGS WILL LIKELY BE ACROSS THE DELTA AND NORTHEAST
ARKANSAS WHERE TEMPERATURES MAY APPROACH 105 DEGREES. HEAT INDICES
MAY CLIMB AS HIGH AS 114 DEGREES.
ALTHOUGH HEAT WILL BE THE MAIN STORY TODAY...THE STORM PREDICTION
CENTER ALSO HAS MUCH OF THE MIDSOUTH IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS. THE INTENSE HEAT AND HIGH HUMIDITY WILL RESULT IN A
VERY UNSTABLE AIRMASS FEATURING CAPE VALUES IN EXCESS OF 3500 J/KG
AND LI`S LOWER THAN -8C. THE MOST UNSTABLE CONDITIONS WILL BE
FOUND IN NORTH MISSISSIPPI AND WEST TENNESSEE. DAMAGING WIND WOULD
BE THE PRIMARY THREAT FROM THESE STORMS. OUTFLOW FROM THE ONGOING
CONVECTION IN CENTRAL TENNESSEE MAY BECOME A FOCUS FOR REDEVELOPMENT
OF STORMS DURING THE DAY TODAY. HAVE NOT SEEN ANY INDICATION THAT
IT HAS PROPAGATED VERY FAR WEST YET...BUT IT COULD LEAD TO BETTER
RAIN CHANCES FARTHER WEST DEPENDING ON ITS EVOLUTION/MOVEMENT.
A WEAK COLD FRONT WILL SINK SOUTH OF THE AREA TONIGHT ALLOWING A
COOLER DRIER AIRMASS TO FILTER INTO THE AREA. AS A RESULT...WE
PROBABLY WILL NOT NEED ANY ADDITIONAL HEAT PRODUCTS TOMORROW.
HIGHS SHOULD BE IN THE MIDDLE 90S AT MOST LOCATIONS. GUIDANCE
DIFFERS SIGNIFICANTLY WITH HIGHS OVER THE NEXT FEW DAYS...WILL
STAY ON THE WARM SIDE OF GUIDANCE BASED ON RECENT TRENDS. TOMORROW
WILL LIKELY BE THE COOLEST DAY OUT OF THE NEXT 7 UNLESS A LOCATION
IS LUCKY ENOUGH TO GET RELIEF FROM RAINFALL. HIGHS ON SATURDAY
WILL BE NEAR NORMAL ACROSS MOST OF THE AREA...GENERALLY 92 TO 94
DEGREES...ALTHOUGH PORTIONS OF EAST ARKANSAS WILL CLIMB BACK INTO
THE UPPER 90S AS A THERMAL RIDGE BUILDS EAST.
THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT
WEEK AS A RIDGE STRENGTHENS OVER THE PLAINS AND SURFACE HIGH
PRESSURE ENCOMPASSES MUCH OT THE DEEP SOUTH. NO ORGANIZED WEATHER
IS ON THE SCOPE...ALTHOUGH WE WILL LIKELY SEE CLIMATOLOGICAL 20-30
PERCENT POPS NEARLY EVERY AFTERNOON. HIGHS FOR MOST OF THE
UPCOMING WORK WEEK WILL BE BETWEEN 95 AND 100 DEGREES.
&&
.AVIATION...
18Z TAFS
PRIMARY SHORT TERM CONCERN IS MVFR CIGS OVER WEST TN AND
NORTHEAST MS. THESE CIGS WERE EMBEDDED IN OUTFLOW FROM A LARGE
TSRA COMPLEX THAT OCCURRED OVER MIDDLE TN LAST EVENING. WHILE
MVFR CIGS WERE SLOWER TO DISSIPATE THAN EARLIER FORECAST... EXPECT
VFR TO RETURN TO TUP AND MKL BY 20Z.
REGARDING AFTERNOON TSRA... OF THE MIDSOUTH TAF SITES...TUP WAS
EARLIER THOUGHT TO HAVE A MENTIONABLE TSRA CHANCE THIS AFTERNOON.
HOWEVER... COOLER MORE STABLE AIRMASS UNDER THE MVFR WILL PRECLUDE
A TEMPO TSRA FOR THE SCHEDULED TUP TAF. SOME TS WILL BE POSSIBLE OVER
NORTH CENTRAL MS HOWEVER. BEST TSRA CHANCE WELL SOUTH OF TUP...
NEAR A CONVERGENT BOUNDARY OVER CENTRAL MS.
VFR SHOULD PREVAIL OVER THE MIDSOUTH THIS EVENING. OVERNIGHT
PERIODS MORE OF A CONCERN. GFS LAMP GUIDANCE CONTINUES TO DEVELOP
LIFR CIGS AND GROUND FOG AT MKL AFTER 09Z. NAM GUIDANCE LESS SO...
BUT DOES INDICATE THE POSSIBILITY OF POST FRONTAL MVFR CIGS EAST
OF MEM TOWARD 12Z. FOR THE 18Z TAFS... HAVE KEPT MEM SCT FOR THE
OVERNIGHT OUTBOUND PUSH.
PWB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 101 78 95 76 / 20 10 10 0
MKL 95 72 93 70 / 20 10 10 0
JBR 102 73 96 73 / 10 0 0 0
TUP 94 74 92 73 / 50 20 20 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CLAY-GREENE-LAWRENCE-
RANDOLPH.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CRAIGHEAD-
CRITTENDEN-CROSS-LEE AR-MISSISSIPPI-PHILLIPS-POINSETT-ST.
FRANCIS.
MO...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CALHOUN-CHICKASAW-
ITAWAMBA-LEE MS-MONROE-PONTOTOC-PRENTISS-TISHOMINGO-UNION.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR ALCORN-BENTON
MS-COAHOMA-DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TUNICA-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CARROLL-DECATUR-HARDIN-
HENDERSON-HENRY-LAKE-OBION-WEAKLEY.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-LAUDERDALE-
MADISON-MCNAIRY-SHELBY-TIPTON.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1100 AM CDT FRI JUL 20 2012
.UPDATE...
CONDITIONS AT 11 AM HAVE WARMED INTO THE 90S WEST OF A LINE FROM
ROUGHLY DYERSBURG TO CLARKSDALE. FURTHER EAST...SOME INFLUENCE
FROM THE ROBUST THUNDERSTORM ACTIVITY IN MIDDLE TENNESSEE /CLOUDS
AND OUTFLOWS/ HAS TEMPERED TEMPERATURES A BIT IN THE 80S. THE
925MB THERMAL RIDGE HAS NOW CENTERED ITSELF ALONG A LINE FROM
OKLAHOMA CITY EAST TO MEMPHIS. AN ILL-DEFINED FRONT APPEARS TO BE
SITUATED OVER NRN MS WITH A FEW STORMS AHEAD OF IT OVER MONROE
COUNTY.
WILL LEAVE THE CURRENT HEADLINE CONFIGURATION IN PLACE...BUT THE
EASTERN COUNTIES WITHIN THE WARNING ARE MARGINAL GIVEN THE CURRENT
CLOUD COVER. NAM 925 MB TEMPS HAVE ALSO COME DOWN A COUPLE
DEGREES...SO REDUCED HIGHS BY A DEGREE OR TWO IN MOST PLACES.
STILL THINK HEAT INDICES OF 110F ARE OBTAINABLE OVER THE DELTA AND
NEAR I-40 IN SWRN TN.
MODELS ARE RELUCTANT TO DEVELOP ANYTHING SIGNIFICANT THIS
AFTERNOON...BUT THE HRRR DOES SHOW ISOLATED CELLS DEVELOPING LATE
THIS AFTERNOON OVER MOST OF THE AREA SO DID NOT FEEL I COULD
REMOVE POPS.
BORGHOFF
&&
.PREV DISCUSSION... /ISSUED 508 AM CDT FRI JUL 20 2012/
DISCUSSION...
TEMPERATURES ARE GENERALLY RUNNING 1-5 DEGREES WARMER THAN THEY
WERE 24 HOURS AGO...AND DEW POINTS ARE AROUND 2 DEGREES WARMER
WITH THE EXCEPTION OF NORTHEAST ARKANSAS WHERE SOME DRIER AIR IS
WORKING IN. 4 AM TEMPERATURES REMAIN IN THE LOW 80S AT MANY
LOCATIONS ACROSS THE MIDSOUTH THE WARMEST READINGS ARE IN THE
DELTA AREAS...INCLUDING THE MEMPHIS METRO AREA WITH THE COOLEST
READINGS IN NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER. A FEW SHOWERS DEVELOPED ALONG THE
TENNESSEE/MISSISSIPPI STATE LINE EARLIER THIS MORNING...BUT HAVE
NOW PRETTY MUCH DISSIPATED. MID AND HIGH CLOUDS OVERSPREAD MOST OF
THE MIDSOUTH HELPING TO LIMIT RADIATIONAL COOLING.
WE SHOULD SEE ANOTHER VERY HOT DAY TODAY DESPITE SOME CLOUD
COVER.AN EXCESSIVE HEAT WARNING HAS BEEN ISSUED FOR MUCH OF THE
AREA. TEMPERATURES WILL START A FEW DEGREES WARMER THAN YESTERDAY
AND WARM QUICKLY INTO THE 90S. CONVECTION WILL GET GOING FAIRLY
EARLY AND MAY PROVIDE SOME LOCALIZED RELIEF TO THE HEAT...BUT DO
NOT THINK COVERAGE...OR THE DURATION OF ANY PRECIPITATION WILL
LIMIT THE HEATING ON ANY LARGE SCALE. THE EXCEPTION MAY BE ACROSS
PORTIONS OF NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER WHERE STORMS ARE EXPECTED TO BE MOST WIDESPREAD.
AFTERNOON HIGHS WILL BE AT OR ABOVE 99 DEGREES ACROSS MOST OF THE
AREA...WITH THE EXCEPTION BEING THE SAME AREA MENTIONED ABOVE. THE
WARMEST READINGS WILL LIKELY BE ACROSS THE DELTA AND NORTHEAST
ARKANSAS WHERE TEMPERATURES MAY APPROACH 105 DEGREES. HEAT INDICES
MAY CLIMB AS HIGH AS 114 DEGREES.
ALTHOUGH HEAT WILL BE THE MAIN STORY TODAY...THE STORM PREDICTION
CENTER ALSO HAS MUCH OF THE MIDSOUTH IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS. THE INTENSE HEAT AND HIGH HUMIDITY WILL RESULT IN A
VERY UNSTABLE AIRMASS FEATURING CAPE VALUES IN EXCESS OF 3500 J/KG
AND LI`S LOWER THAN -8C. THE MOST UNSTABLE CONDITIONS WILL BE
FOUND IN NORTH MISSISSIPPI AND WEST TENNESSEE. DAMAGING WIND WOULD
BE THE PRIMARY THREAT FROM THESE STORMS. OUTFLOW FROM THE ONGOING
CONVECTION IN CENTRAL TENNESSEE MAY BECOME A FOCUS FOR REDEVELOPMENT
OF STORMS DURING THE DAY TODAY. HAVE NOT SEEN ANY INDICATION THAT
IT HAS PROPAGATED VERY FAR WEST YET...BUT IT COULD LEAD TO BETTER
RAIN CHANCES FARTHER WEST DEPENDING ON ITS EVOLUTION/MOVEMENT.
A WEAK COLD FRONT WILL SINK SOUTH OF THE AREA TONIGHT ALLOWING A
COOLER DRIER AIRMASS TO FILTER INTO THE AREA. AS A RESULT...WE
PROBABLY WILL NOT NEED ANY ADDITIONAL HEAT PRODUCTS TOMORROW.
HIGHS SHOULD BE IN THE MIDDLE 90S AT MOST LOCATIONS. GUIDANCE
DIFFERS SIGNIFICANTLY WITH HIGHS OVER THE NEXT FEW DAYS...WILL
STAY ON THE WARM SIDE OF GUIDANCE BASED ON RECENT TRENDS. TOMORROW
WILL LIKELY BE THE COOLEST DAY OUT OF THE NEXT 7 UNLESS A LOCATION
IS LUCKY ENOUGH TO GET RELIEF FROM RAINFALL. HIGHS ON SATURDAY
WILL BE NEAR NORMAL ACROSS MOST OF THE AREA...GENERALLY 92 TO 94
DEGREES...ALTHOUGH PORTIONS OF EAST ARKANSAS WILL CLIMB BACK INTO
THE UPPER 90S AS A THERMAL RIDGE BUILDS EAST.
THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT
WEEK AS A RIDGE STRENGTHENS OVER THE PLAINS AND SURFACE HIGH
PRESSURE ENCOMPASSES MUCH OT THE DEEP SOUTH. NO ORGANIZED WEATHER
IS ON THE SCOPE...ALTHOUGH WE WILL LIKELY SEE CLIMATOLOGICAL 20-30
PERCENT POPS NEARLY EVERY AFTERNOON. HIGHS FOR MOST OF THE
UPCOMING WORK WEEK WILL BE BETWEEN 95 AND 100 DEGREES.
&&
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS SHOULD CONTINUE FOR MUCH OF THE FORECAST PERIOD.
SOME SHOWERS AND THUNDERSTORMS MAY DEVELOP THIS AFTERNOON WITH THE
BEST CHANCE OVER NORTH MISSISSIPPI WHICH COULD PRODUCE BRIEF
PERIODS OF MVFR CEILINGS AND VISIBILITIES. WINDS WILL START OUT
FROM THE SOUTHWEST THIS MORNING BUT GRADUALLY SHIFT TOE NORTHWEST
THIS AFTERNOON AND EVENTUALLY TO THE NORTH OVERNIGHT.
ARS
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 101 78 96 74 / 20 10 10 0
MKL 95 72 93 68 / 20 10 10 0
JBR 102 73 98 72 / 10 0 0 0
TUP 94 74 92 71 / 50 20 20 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CLAY-GREENE-LAWRENCE-
RANDOLPH.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CRAIGHEAD-
CRITTENDEN-CROSS-LEE AR-MISSISSIPPI-PHILLIPS-POINSETT-ST.
FRANCIS.
MO...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CALHOUN-CHICKASAW-
ITAWAMBA-LEE MS-MONROE-PONTOTOC-PRENTISS-TISHOMINGO-UNION.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR ALCORN-BENTON
MS-COAHOMA-DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TUNICA-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CARROLL-DECATUR-HARDIN-
HENDERSON-HENRY-LAKE-OBION-WEAKLEY.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-LAUDERDALE-
MADISON-MCNAIRY-SHELBY-TIPTON.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1239 PM CDT FRI JUL 20 2012
.DISCUSSION...
SEE AVIATION DISCUSSION.
&&
.AVIATION...
GENERALLY VFR CONDS EXPECTED TODAY. UPPER HIGH OVER THE CENTRAL
PLAINS AND SURFACE HIGH PRESSURE OVER THE WESTERN GULF SHOULD KEEP
PRECIP TO THE EAST OF TAF SITES TODAY. FCST SOUNDINGS DON`T SHOW
MUCH IN THE WAY OF LOW CLOUDS FOR SAT MORNING BUT WILL LEAN A BIT
TOWARD PERSISTENCE AND HINT AT MVFR CIGS FOR IAH NORTHWARD.
CONVECTIVE POTENTIAL INCREASES TOMORROW AFTN (AFTER 18Z) WITH PW
VALUES APPROACHING 2 INCHES AND K INDEX VALUES APPROACHING 40. 43
&&
.PREV DISCUSSION... /ISSUED 1056 AM CDT FRI JUL 20 2012/
UPDATE...
ONLY MINOR GRID UPDATES TO INCREASE AREAWIDE DEW POINTS/RHS...AND
TO FOCUS HIGHER CHANCE POPS OVER THE SOUTHEASTERN FORECAST AREA
THIS AFTERNOON. HIGHER PVA RIDING AROUND THE SOUTHERN PERIPHERY OF
UPPER RIDGING CENTERED OVER THE WESTERN PLAINS IS CREATING THE
UNSETTLED WEATHER OFF THE COAST OF LOUISIANA. THE GENERAL
CONSENSUS AMONGST THE MODELS IS TO KEEP THE BULK OF THIS ENERGY
OVER LCH`S WESTERN CWA...TRAVELING FURTHER OFFSHORE. THUS...THERE
APPEARS TO BE A STARK DELINEATION CONCERNING RAINFALL OVER EXTREME
EASTERN TEXAS/NW GULF VERSUS MUCH DRIER CONDITIONS (PRECIPITATION-
WISE) FOR OUR REGION GOING INTO THE WEEKEND. INCREASING NEAR 2
INCH PWATS FROM THE WESTERN ADVECTION OF LOUISIANA`S MOIST AIR
MASS PER MID-LEVEL EASTERLY FLOW. FOR TODAY...LOW 90F CONVECTIVE
TEMPERATURES WITHIN A MOISTENING AND HEATED MID 90F EARLY AFTERNOON
ENVIRONMENT ENSURES AT LEAST 20 PERCENT MID-LATE AFTERNOON SHOWER/
ISOLATED STORM COVERAGE. 31
PREV DISCUSSION... /ISSUED 418 AM CDT FRI JUL 20 2012/
DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 78 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 78 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 82 91 81 92 / 30 30 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1056 AM CDT FRI JUL 20 2012
.UPDATE...
ONLY MINOR GRID UPDATES TO INCREASE AREAWIDE DEW POINTS/RHS...AND
TO FOCUS HIGHER CHANCE POPS OVER THE SOUTHEASTERN FORECAST AREA
THIS AFTERNOON. HIGHER PVA RIDING AROUND THE SOUTHERN PERIPHERY OF
UPPER RIDGING CENTERED OVER THE WESTERN PLAINS IS CREATING THE
UNSETTLED WEATHER OFF THE COAST OF LOUISIANA. THE GENERAL
CONSENSUS AMONGST THE MODELS IS TO KEEP THE BULK OF THIS ENERGY
OVER LCH`S WESTERN CWA...TRAVELING FURTHER OFFSHORE. THUS...THERE
APPEARS TO BE A STARK DELINEATION CONCERNING RAINFALL OVER EXTREME
EASTERN TEXAS/NW GULF VERSUS MUCH DRIER CONDITIONS (PRECIPITATION-
WISE) FOR OUR REGION GOING INTO THE WEEKEND. INCREASING NEAR 2
INCH PWATS FROM THE WESTERN ADVECTION OF LOUISIANA`S MOIST AIR
MASS PER MID-LEVEL EASTERLY FLOW. FOR TODAY...LOW 90F CONVECTIVE
TEMPERATURES WITHIN A MOISTENING AND HEATED MID 90F EARLY AFTERNOON
ENVIRONMENT ENSURES AT LEAST 20 PERCENT MID-LATE AFTERNOON SHOWER/
ISOLATED STORM COVERAGE. 31
&&
.PREV DISCUSSION... /ISSUED 631 AM CDT FRI JUL 20 2012/
DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION
AVIATION...
A FEW LOW CLOUDS ACROSS THE REGION THIS MORNING BUT VFR CONDITIONS
ARE EXPECTED FOR THE BULK OF THE TAF VALID PERIOD. SOUTHWESTERLY
WINDS ARE EXPECTED TODAY AS HIGH PRESSURE CONTINUES TO BUILD
ACROSS THE NORTHERN GULF OF MEXICO. THUNDERSTORMS ARE EXPECTED TO
BE RATHER ISOLATED AS SUBSIDENCE ALOFT WILL HELP TO CAP CONVECTION
THIS AFTERNOON. WITH THIS IN MIND HAVE REMOVED THE MENTION OF VCSH
FOR TODAY AS COVERAGE WILL BE TOO LOW TO WARRANT A MENTION IN THE
TAFS. 38
PREV DISCUSSION... /ISSUED 418 AM CDT FRI JUL 20 2012/
DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 78 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 78 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 82 91 81 92 / 30 30 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
631 AM CDT FRI JUL 20 2012
.DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION
&&
.AVIATION...
A FEW LOW CLOUDS ACROSS THE REGION THIS MORNING BUT VFR CONDITIONS
ARE EXPECTED FOR THE BULK OF THE TAF VALID PERIOD. SOUTHWESTERLY
WINDS ARE EXPECTED TODAY AS HIGH PRESSURE CONTINUES TO BUILD
ACROSS THE NORTHERN GULF OF MEXICO. THUNDERSTORMS ARE EXPECTED TO
BE RATHER ISOLATED AS SUBSIDENCE ALOFT WILL HELP TO CAP CONVECTION
THIS AFTERNOON. WITH THIS IN MIND HAVE REMOVED THE MENTION OF VCSH
FOR TODAY AS COVERAGE WILL BE TOO LOW TO WARRANT A MENTION IN THE
TAFS. 38
&&
.PREV DISCUSSION... /ISSUED 418 AM CDT FRI JUL 20 2012/
DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 77 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 77 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 81 91 81 92 / 20 20 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...04
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
418 AM CDT FRI JUL 20 2012
.DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
&&
.MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 77 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 77 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 81 91 81 92 / 20 20 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...04
AVIATION/MARINE...38
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1017 PM MDT SAT JUL 21 2012
.UPDATE...
ISSUED AT 1011 PM MDT SAT JUL 21 2012
MOST OF THE CONVECTION HAS MOVED NORTH OF I-70 AND SPREADING
ACROSS THE NORTHWEST PLATEAU ACROSS RIO BLANCO AND MOFFAT
COUNTIES. ONLY A FEW STRAY LIGHTNING STRIKES REMAIN. SOUTH OF I-70
SHOWERS AND TSTMS HAVE DECREASED SUBSTANTIALLY. HAVE TRENDED AREAL
COVERAGE DOWN QUICKLY ACROSS THE FORECAST AREA OVER THE NEXT 6 HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 247 PM MDT SAT JUL 21 2012
MOIST SUBTROPICAL FLOW WITH CONTINUE THROUGH THE WEEKEND. ATMOSPHERE
CONTINUES TO BE QUITE MOIST AS SHOWN BY THE GJT SOUNDING AND MODEL
SOLUTIONS. WATER VAPOR AND RUC13 PICKING UP A SHORT WAVE MOVING
NORTHWEST ACROSS UTAH THIS AFTERNOON WHICH WILL KEEP BEST FORCING
FROM THIS WAVE WEST OF THE CWA. HOWEVER...AS DIURNAL HEATING
INCREASES THIS AFTERNOON EXPECT CONVECTION TO INCREASE INTO THE
EVENING HOURS. IN ADDITION...RUC13 AND NAM12 ALSO SHOW INDICATIONS
OF ANOTHER SHORT WAVE WHICH WILL MOVE NORTH ACROSS SOUTHWESTERN
COLORADO THIS EVENING AND PRODUCE ADDITIONAL LIFT FOR THIS MOIST AND
UNSTABLE AIRMASS. SHOWERS AND THUNDERSTORM ACTIVITY WILL DECREASE
OVERNIGHT...BUT WOULD NOT RULE OUT SOME ADDITIONAL ACTIVITY DURING
THE EARLY MORNING HOURS. MODELS SHOW MORE OF THE SAME FOR SUNDAY AS
MOIST UNSTABLE SOUTHERLY FETCH CONTINUES OVER THE FORECAST AREA WITH
ANOTHER ROUND OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS...DECREASING OVERNIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 247 PM MDT SAT JUL 21 2012
A COUPLE OF MINOR CHANGES SEEN DURING THIS PERIOD...OTHERWISE VERY
LITTLE DIFFERENCE SEEN IN THE SENSIBLE WX PATTERN. HIGH PRESSURE
OVER THE PLAINS CONTINUES TO BE A FAVORABLE POSITION TO BRING A
STEADY STREAM OF MONSOONAL MOISTURE INTO THE SWRN U.S. INCLUDING ERN UT
AND WRN CO. IN THE MEANTIME A CLOSED UPPER LOW OVER THE PACIFIC NW
MOVES EWRD INTO SRN ALBERTA BY TUESDAY AFTERNOON. THIS FLATTENS
THE RIDGE SOME AND RESULTS IN THE UPPER LEVEL WINDS TRANSITIONING
FROM SWRLY TO NWRLY BY TUES AFTERNOON. BUT LIKE STATED ABOVE
LITTLE IF ANY IMPACT IS SEEN ON OUR SENSIBLE WX PATTERN. THIS HAS
BEEN HIGHLIGHTED BY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM
FORMATION FOCUSED OVER THE HIGHER TERRAIN.
A SLIGHT DOWNTURN IN CONVECTION IS SEEN WED/THU AS A DRIER
NORTHWESTERLY FLOW INVADES THE REGION. HOWEVER IT IS QUICKLY
FOLLOWED BY THE NEXT SURGE OF SUBTROPICAL MOISTURE WHICH SHOULD
OCCUR FRIDAY AND SATURDAY AS THE FLOW SWITCHES BACK TO THE
SOUTHWEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1011 PM MDT SAT JUL 21 2012
VFR CONDITIONS AREA EXPECTED OVERNIGHT AND THROUGH EARLY SUNDAY
AFTERNOON AT ALL TAF SITES. BY MID-AFTERNOON SUNDAY EXPECT
SCATTERED TO NUMEROUS SHOWERS AND TSTMS TO DEVELOP AGAIN...
PRODUCING LOCAL MVFR CIGS AND VSBY IN HEAVIER SHOWERS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...CC
SHORT TERM...MPM
LONG TERM...MC
AVIATION...CC
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1203 AM CDT SUN JUL 22 2012
.UPDATE...
ADDED 06Z TAF DISCUSSION.
CONVECTION HAS ALREADY EXPANDED ACROSS FAR SRN SD AND SRN MN SO HAVE
UPPED PRECIP CHANCES FAR NORTH.
PREVIOUS UPDATE...NO APPRECIABLE CHANGES TO FORECAST TONIGHT. WAS
SOME CONCERN REGARDING FATE OF SMALL CONVECTIVE CLUSTER APPROACHING
YANKTON AS IT RODE TOP OF ELEVATED MIXED LAYER...BUT THAT CONTINUES
TO DISSIPATE. EXAMINATION OF RAP ELEVATED INSTABILITY LAYERS
SUGGESTS MOST FAVORABLE CAPE/CIN ALOFT CONTINUES TO LIFT NORTHWARD
INTO SD AND MN OVERNIGHT. THIS APPEARS TO BE COINCIDENT WITH SHARP
BAROCLINIC ZONE NOTED ALONG RAP 315K ISENT SURFACE. STRONG UVM AND
MOISTURE CONVERGENCE IS NOTED ON NOSE OF 30-40KT FLOW AFTER MIDNIGHT
WITH ISENT SURFACE CHANGING FROM 900-700MB ALONG TRAJECTORY FROM
CENTRAL NE INTO SWRN MN. WITH THIS IN MIND EXPECT CURRENT WRN SD
MCS TO EXPAND EASTWARD EARLY SUN MORNING...AND/OR AN INCREASE OF
CURRENT ELEVATED SHOWERS FESTERING OVER SRN MN. MAY EVEN SEE SOME
SORT OF CONNECTION. SEVERAL SUPPORTING WRF RUNS AND THE LATEST HRRR
FOCUS ALONG THE SD/MN BORDER...WITH THE HRRR EVEN BLOSSOMING
CONVECTION INTO IA OVERNIGHT. FEEL THIS IS TOO AGGRESSIVE SOUTH
CONSIDERING THE MEAN WIND BEING MORE EAST THAN SOUTH...BUT SEE NO
REASON TO CHANGE CURRENT OVERNIGHT LOW POPS NORTH AT THIS POINT.
&&
.SHORT TERM /TONIGHT/...
SERIES OF VORTICITY CENTERS TUMBLING DOWN EAST SIDE OF UPPER RIDGE
AND SOME MID-LEVEL WARM ADVECTION HAVE KEPT SHOWERS GOING INTO THE
AFTERNOON ACROSS NORTHERN AND EASTERN IOWA. ASSOCIATED SPILLAGE OF
CLOUDS FARTHER SOUTH HELD DOWN HIGH TEMPERATURES SOMEWHAT TODAY BUT
DID NOT PRODUCE ANY BENEFICIAL RAINFALL. IT APPEARS THE PATTERN
WON`T CHANGE MUCH OVERNIGHT...AND WITH ANOTHER VORTICITY CENTER
SHOWING UP NEAR THE BLACK HILLS AND ANOTHER SURGE OF 850 MB WINDS
OVERNIGHT...CONVECTION SHOULD DEVELOP AGAIN NEAR THE MINNESOTA
BORDER BY MIDNIGHT OR SO. AGAIN...THIS SHOULD NOT BE VERY INTENSE
AND WILL REMAIN ELEVATED...BUT IT WILL HAVE CONSEQUENCES FOR CLOUD
COVER INTO SUNDAY. LIGHT SOUTH FLOW WILL PERSIST OVERNIGHT AT THE
SURFACE WITH THE LOW PRESSURE CENTER REMAINING IN SOUTH DAKOTA. TO
THIS POINT...THE SOUTH WINDS ARE NOT BRINGING IN A LOT OF
HUMIDITY...EXCEPT IN NORTHERN IOWA NEARER THE SURFACE BOUNDARY WHICH
IS POSITIONED IN SOUTHERN MINNESOTA. AS A RESULT...LOW TEMPERATURES
SHOULD DROP TO NEAR 70 DEGREES IN MOST LOCATIONS WITH THE EXCEPTION
OF THE DES MOINES AND CENTRAL IOWA HEAT ISLANDS.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
FORECAST CONCERNS IN THE EXTENDED REVOLVE AROUND WHERE THE
CONVECTION AND CLOUDS WILL HAMPER TEMPS AND AFFECT THE EXCESSIVE
HEAT WARNING. THE EFFECTS OF WHICH WERE MADE EVIDENT TODAY. THE
MODELS ARE CONSISTENT IN KEEPING SHORTWAVES RIDGING OVER THE
PERIPHERY OF THE UPPER LEVEL RIDGE. MODELS ARE CONSISTENT IN
DEVELOPING STORMS OVER SOUTHERN MINNESOTA AND CORFIDI VECTORS DROP
THE STORMS INTO NORTHERN/EASTERN IOWA...MUCH LIKE TODAY...EXCEPT
THAT THE SOUTHERN EXTEND OF THE STORMS IS A BIT MORE IN QUESTION.
NONE THE LESS...CLOUD COVER WILL BE OVER THE AREA AND AFFECT THE
TEMPS. HEAT INDICES...ESPECIALLY ACROSS THE SOUTH AND WEST...WHILE
A LITTLE LOWER ARE STILL IN THE 101-106 RANGE. THIS FALLS A BIT
SHORT OF THE WARNING CRITERIA BUT IF WE GET A LITTLE MORE SUN OR
THE STORMS DON`T EVOLVE AS FAR SOUTH THEN WE WILL HAVE NO PROBLEM
HEATING UP. MY CONFIDENCE IS NOT HIGH ENOUGH TO CHANGE THE WARNING
AT THIS POINT. THERE IS ONE EXCEPTION...NORTH OF HIGHWAY 20 IS THE
MOST UNLIKELY AREA TO SEE EXCESSIVE HEAT. SHOWERS/CLOUDS WILL
PLAGUE THIS AREA JUST ABOUT EVERY DAY OF THE WARNING. FOR THIS
REASON I HAVE DROPPED THE WARNING NORTH OF HIGHWAY 20 WHICH
AMOUNTS TO ONE TIER OF COUNTIES.
MONDAY AND TUESDAY DEFINITELY LOOK LIKE THE HOTTEST DAYS OF THE
WEEK SO LITTLE CHANGES MADE TO THE FORECAST HERE EXCEPT TO TWEAK
TEMPS A BIT.
FOR WEDNESDAY A STRONG UPPER LEVEL LOW TRAVELING ACROSS SOUTHERN
CANADA WILL FLATTEN THE RIDGE WHILE AT THE SURFACE A WEAK COLD
FRONT WILL SHIFT ACROSS THE FORECAST AREA. THERE IS DECENT FORCING
ALONG THE BOUNDARY AND OFFERS OUR BEST CHANCE AT SEEING
CLOUDS/STORMS. TIMING OF THE BOUNDARY AT THIS POINT REMAINS IN
QUESTION WHICH PUTS INTO QUESTION WHETHER WE WILL NEED AN
EXCESSIVE HEAT WARNING FOR WEDNESDAY BUT AGAIN...MY CONFIDENCE IS
NOT HIGH ENOUGH TO DROP IT FOR THE PERIOD SO I WILL LET IT RIDE
FOR NOW. HOWEVER...I DID INCREASE POPS/CLOUDS AND KNOCK TEMPS
BACK A BIT. THE SAME LOGIC IS APPLIED FOR THIS PERIOD AS WELL. WE
FALL A BIT SHY ON THE CRITERIA BUT IF WE GET A BIT MORE SUN OR THE
FRONT SLOWS...WE WILL HAVE NO PROBLEM REACHING CRITERIA.
AS FOR THE REST OF THE EXTENDED...THE RIDGE REBUILDS TO OUR WEST
PUTTING US IN A MORE NW FLOW WITH WEAK HIGH PRESSURE AT THE
SURFACE. THIS WILL BRING A BREAK TO THE HEAT AND ACTUALLY PRODUCE
HIGHS THAT ARE MORE SEASONAL. HIGHS BY NEXT WEEKEND WILL BE IN THE
MID TO UPPER 80S WHICH WILL BE A WELCOME RELIEF TO WHAT WE HAVE HAD.
&&
.AVIATION...22/06Z
PRIMARY CONCERN WILL BE CONVECTIVE TRENDS OVERNIGHT. THUNDERSTORMS
CONTINUE TO EXPAND OVER SRN SD AND SRN MN AND EXPECT THE COMPLEXES
EVENTUALLY TURN SEWD AFFECTING NRN SITES /KMCW/KALO/. CIGS WILL
PRIMARY REMAIN VFR THROUGH THE PERIOD...BUT COULD BRIEFLY DIP TO
MVFR CIGS OR VSBYS IF A HEAVIER STORM IMPACTS A SITE. CONFIDENCE IN
THIS OCCURRING IS NOT GREAT HOWEVER SO HAVE NOTHING MORE THAN VFR
VCTS. ANY CONVECTION SHOULD EXIT THE AREA BY SUN MORNING WITH SLY
WINDS INCREASING AND BECOMING SOMEWHAT GUSTY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING UNTIL 3PM WED
ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-
CRAWFORD-DALLAS-DECATUR-GREENE-GUTHRIE-HAMILTON-JASPER-LUCAS-MADISON-
MARION-MONROE-POLK-RINGGOLD-SAC-STORY-TAYLOR-UNION-WARREN-WAYNE-
WEBSTER
EXCESSIVE HEAT WARNING FROM 1PM SUN TO 3PM WED
BLACK HAWK-DAVIS-GRUNDY-HARDIN-MAHASKA-MARSHALL-POWESHIEK-TAMA-
WAPELLO
&&
$$
LONG TERM...FAB
SHORT TERM...JUNGBLUTH
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1054 PM MDT SAT JUL 21 2012
.UPDATE...
ISSUED AT 903 PM MDT SAT JUL 21 2012
THE RED FLAG WARNING WAS ALLOWED TO EXPIRE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1251 PM MDT SAT JUL 21 2012
AS OF EARLY THIS AFTERNOON THE CENTER OF THE UPPER LEVEL HIGH IS
JUST NORTHEAST OF THE CWA ALLOWING THIN CIRRUS TO ROTATE NORTHWEST
OVER MUCH OF THE AREA. SOME FLAT CU HAS ALSO DEVELOPED OVER THE FAR
WRN QUARTER OF THE CWA ATOP A LEE TROUGH. TEMPS THUS FAR FOR MOST
LOCATIONS ARE AT OR ABOVE THE CENTURY MARK.
FOR THE REST OF THE AFTERNOON RELATIVE HUMIDITIES SHOULD CONTINUE
TO SLOWLY DECREASE ESPECIALLY ACROSS THE WRN ZONES WHERE THE RED FLAG
WARNING IS IN PLACE. THE SFC WINDS HAVE BEEN RATHER LIGHT IN THE
15 TO 25 MPH RANGE THUS FAR...SO ONLY PORTIONS OF THE WARNING ARE
VERIFYING TO THIS POINT. HAVE LEFT THE FCST DRY TODAY THROUGH
TOMORROW DESPITE THE HRRR GENERATING ISOLATED STORMS THIS
AFTERNOON ALONG/NEAR THE SFC TROUGH (WHERE THE CU IS CURRENTLY
LOCATED).
FOR TONIGHT I WENT WITH A PERSISTENCE FORECAST FOLLOWING LAST
NIGHT/S LOW TEMPS ALONG WITH LIGHT SOUTHERLY WINDS AND MOSTLY
CLEAR SKIES. TOMORROW WILL ONCE AGAIN BE HOT WITH LOW 100S ACROSS
THE BOARD...WARMEST EAST WHERE THE HEAT ADVISORY IS. HAVE DEBATED
WHETHER TO ISSUE A FIRE WEATHER WATCH FOR TOMORROW FOR GENERALLY
THE SAME LOCATIONS AS TODAY/S RED FLAG WARNING. THE FORECASTED
RELATIVE HUMIDITIES REACH CRITERIA BUT THE WINDS APPEAR A BIT TOO
LIGHT. WANT TO SEE HOW TODAY PLAYS OUT AS TODAY AND TOMORROW ARE
NEARLY IDENTICAL FOR MET CONDITIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 233 PM MDT SAT JUL 21 2012
THE STRONG H5 RIDGE REMAINS IN PLACE THROUGH MONDAY NIGHT. VERY
LITTLE CHANGES REGARDING THE AIRMASS ALOFT WITH SIMILAR HIGH TEMPS
EACH DAY THROUGH MIDWEEK. NO CHANGE TO CURRENT HEAT ADVISORY WITH
EASTERN LOCATIONS EXPECTED TO HAVE HEAT INDEX VALUES AROUND 105.
TEMPERATURES ALOFT WILL COOL SOME AFTER TUESDAY AS H5 HEIGHTS
BEGIN TO DECREASE...HOWEVER WITH RIDGING OF SOME FASHION EXPECTED
TO CONTINUE...ABOVE NORMAL TEMPERATURES IN THE UPPER 90S/NEAR 100
WILL CONTINUE THROUGH THE EXTENDED PERIODS.
DRY CONDITIONS ARE EXPECTED TO PERSIST WITH RED FLAG CONDITIONS
POSSIBLE AGAIN ON MONDAY...DEPENDING ON WINDS. BEST CHANCE FOR PRECIP
WILL BE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT WHEN A STRONG
UPPER LOW MOVES ACROSS SOUTHERN CANADA...AND A TRAILING SHORTWAVE
TROUGH MOVES ACROSS THE PLAINS. THERE REMAINS UNCERTAINTY REGARDING
THE POSITION/STRENGTH OF THE TRAINING SHORTWAVE...WITH ECMWF FURTHER
SOUTH AND STRONGER. IGNORING THE DIFFERENCES REGARDING LARGE SCALE
ASCENT...MOISTURE PROFILES ARE UNIMPRESSIVE. DEEP DRY LAYER TO 650MB
REMAINS IN PLACE THROUGH THESE PERIODS. BASED ON SOUNDINGS ISOLATED
DRY THUNDERSTORMS MAY ULTIMATELY BE FAVORED...HOWEVER WITH BOTH GFS
AND ECMWF ARE BOTH SHOWING QPF OF SOME SORT AROUND THE AREA SO
MEASURABLE PRECIP CANT BE RULED OUT. I DECIDED TO KEEP ISOLATED
THUNDERSTORM MENTION FOR NOW. RIDGING BEGINS TO BUILD BACK OVER THE
INTER-MOUNTAIN WEST ON THURSDAY AND SHOULD CONTINUE TO DOMINATE THE
WEATHER OVER THE PLAINS THROUGH NEXT WEEKEND. THERE IS SOME
INDICATION OF A SHORTWAVE TROUGH PASSAGE NEXT WEEKEND OVER EASTERN
NEBRASKA...HOWEVER MOISTURE SEEMS TO BE CUT OFF FROM OUR AREA. WITH
STABLE AIR MASS ALOFT OVER OUR CWA..CONFIDENCE IS LOW IN ANY
ACTIVITY INITIATING OVER OUR CWA...SO I KEPT FORECAST DRY AFTER
WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1053 PM MDT SAT JUL 21 2012
LITTLE TO NO CHANGE WITH VFR CONDITIONS EXPECTED THROUGH THE
PERIOD. SOUTHERLY WINDS WILL BECOME GUSTY AS THE AIR MASS QUICKLY
HEATS UP.
&&
.CLIMATE...
ISSUED AT 233 PM MDT SAT JUL 21 2012
VERY HOT TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH NEXT
WEEK...WITH SEVERAL LOCATIONS POSSIBLY BREAKING DAILY TEMPERATURE
RECORDS.
DAILY RECORDS FOR SUNDAY (JUL 22)...
GOODLAND.....105 (1934)
HILL CITY....108 (1934)
BURLINGTON...104 (1990)
MCCOOK.......110 (1931)
YUMA.........109
TRIBUNE......107
COLBY........107
DAILY RECORDS FOR MONDAY (JUL 23)...
GOODLAND.....110 (1936)
HILL CITY....107 (1940)
BURLINGTON...105 (1963)
MCCOOK.......106 (1940)
YUMA.........107
TRIBUNE......107
COLBY........105
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR KSZ002>004-014>016-028-
029-042.
CO...NONE.
NE...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR NEZ080-081.
&&
$$
UPDATE...BULLER
SHORT TERM...05
LONG TERM...DR
AVIATION...BULLER
CLIMATE...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
904 PM MDT SAT JUL 21 2012
.UPDATE...
ISSUED AT 903 PM MDT SAT JUL 21 2012
THE RED FLAG WARNING WAS ALLOWED TO EXPIRE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1251 PM MDT SAT JUL 21 2012
AS OF EARLY THIS AFTERNOON THE CENTER OF THE UPPER LEVEL HIGH IS
JUST NORTHEAST OF THE CWA ALLOWING THIN CIRRUS TO ROTATE NORTHWEST
OVER MUCH OF THE AREA. SOME FLAT CU HAS ALSO DEVELOPED OVER THE FAR
WRN QUARTER OF THE CWA ATOP A LEE TROUGH. TEMPS THUS FAR FOR MOST
LOCATIONS ARE AT OR ABOVE THE CENTURY MARK.
FOR THE REST OF THE AFTERNOON RELATIVE HUMIDITIES SHOULD CONTINUE
TO SLOWLY DECREASE ESPECIALLY ACROSS THE WRN ZONES WHERE THE RED FLAG
WARNING IS IN PLACE. THE SFC WINDS HAVE BEEN RATHER LIGHT IN THE
15 TO 25 MPH RANGE THUS FAR...SO ONLY PORTIONS OF THE WARNING ARE
VERIFYING TO THIS POINT. HAVE LEFT THE FCST DRY TODAY THROUGH
TOMORROW DESPITE THE HRRR GENERATING ISOLATED STORMS THIS
AFTERNOON ALONG/NEAR THE SFC TROUGH (WHERE THE CU IS CURRENTLY
LOCATED).
FOR TONIGHT I WENT WITH A PERSISTENCE FORECAST FOLLOWING LAST
NIGHT/S LOW TEMPS ALONG WITH LIGHT SOUTHERLY WINDS AND MOSTLY
CLEAR SKIES. TOMORROW WILL ONCE AGAIN BE HOT WITH LOW 100S ACROSS
THE BOARD...WARMEST EAST WHERE THE HEAT ADVISORY IS. HAVE DEBATED
WHETHER TO ISSUE A FIRE WEATHER WATCH FOR TOMORROW FOR GENERALLY
THE SAME LOCATIONS AS TODAY/S RED FLAG WARNING. THE FORECASTED
RELATIVE HUMIDITIES REACH CRITERIA BUT THE WINDS APPEAR A BIT TOO
LIGHT. WANT TO SEE HOW TODAY PLAYS OUT AS TODAY AND TOMORROW ARE
NEARLY IDENTICAL FOR MET CONDITIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 233 PM MDT SAT JUL 21 2012
THE STRONG H5 RIDGE REMAINS IN PLACE THROUGH MONDAY NIGHT. VERY
LITTLE CHANGES REGARDING THE AIRMASS ALOFT WITH SIMILAR HIGH TEMPS
EACH DAY THROUGH MIDWEEK. NO CHANGE TO CURRENT HEAT ADVISORY WITH
EASTERN LOCATIONS EXPECTED TO HAVE HEAT INDEX VALUES AROUND 105.
TEMPERATURES ALOFT WILL COOL SOME AFTER TUESDAY AS H5 HEIGHTS
BEGIN TO DECREASE...HOWEVER WITH RIDGING OF SOME FASHION EXPECTED
TO CONTINUE...ABOVE NORMAL TEMPERATURES IN THE UPPER 90S/NEAR 100
WILL CONTINUE THROUGH THE EXTENDED PERIODS.
DRY CONDITIONS ARE EXPECTED TO PERSIST WITH RED FLAG CONDITIONS
POSSIBLE AGAIN ON MONDAY...DEPENDING ON WINDS. BEST CHANCE FOR PRECIP
WILL BE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT WHEN A STRONG
UPPER LOW MOVES ACROSS SOUTHERN CANADA...AND A TRAILING SHORTWAVE
TROUGH MOVES ACROSS THE PLAINS. THERE REMAINS UNCERTAINTY REGARDING
THE POSITION/STRENGTH OF THE TRAINING SHORTWAVE...WITH ECMWF FURTHER
SOUTH AND STRONGER. IGNORING THE DIFFERENCES REGARDING LARGE SCALE
ASCENT...MOISTURE PROFILES ARE UNIMPRESSIVE. DEEP DRY LAYER TO 650MB
REMAINS IN PLACE THROUGH THESE PERIODS. BASED ON SOUNDINGS ISOLATED
DRY THUNDERSTORMS MAY ULTIMATELY BE FAVORED...HOWEVER WITH BOTH GFS
AND ECMWF ARE BOTH SHOWING QPF OF SOME SORT AROUND THE AREA SO
MEASURABLE PRECIP CANT BE RULED OUT. I DECIDED TO KEEP ISOLATED
THUNDERSTORM MENTION FOR NOW. RIDGING BEGINS TO BUILD BACK OVER THE
INTER-MOUNTAIN WEST ON THURSDAY AND SHOULD CONTINUE TO DOMINATE THE
WEATHER OVER THE PLAINS THROUGH NEXT WEEKEND. THERE IS SOME
INDICATION OF A SHORTWAVE TROUGH PASSAGE NEXT WEEKEND OVER EASTERN
NEBRASKA...HOWEVER MOISTURE SEEMS TO BE CUT OFF FROM OUR AREA. WITH
STABLE AIR MASS ALOFT OVER OUR CWA..CONFIDENCE IS LOW IN ANY
ACTIVITY INITIATING OVER OUR CWA...SO I KEPT FORECAST DRY AFTER
WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 541 PM MDT SAT JUL 21 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WINDS WILL BE
GUSTY...ESPECIALLY AT KGLD...WHEN THE HEATING OF THE DAY OCCURS.
&&
.CLIMATE...
ISSUED AT 233 PM MDT SAT JUL 21 2012
VERY HOT TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH NEXT
WEEK...WITH SEVERAL LOCATIONS POSSIBLY BREAKING DAILY TEMPERATURE
RECORDS.
DAILY RECORDS FOR SUNDAY (JUL 22)...
GOODLAND.....105 (1934)
HILL CITY....108 (1934)
BURLINGTON...104 (1990)
MCCOOK.......110 (1931)
YUMA.........109
TRIBUNE......107
COLBY........107
DAILY RECORDS FOR MONDAY (JUL 23)...
GOODLAND.....110 (1936)
HILL CITY....107 (1940)
BURLINGTON...105 (1963)
MCCOOK.......106 (1940)
YUMA.........107
TRIBUNE......107
COLBY........105
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR KSZ002>004-014>016-028-
029-042.
CO...NONE.
NE...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR NEZ080-081.
&&
$$
UPDATE...BULLER
SHORT TERM...05
LONG TERM...DR
AVIATION...BULLER
CLIMATE...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
542 PM MDT SAT JUL 21 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1251 PM MDT SAT JUL 21 2012
AS OF EARLY THIS AFTERNOON THE CENTER OF THE UPPER LEVEL HIGH IS
JUST NORTHEAST OF THE CWA ALLOWING THIN CIRRUS TO ROTATE NORTHWEST
OVER MUCH OF THE AREA. SOME FLAT CU HAS ALSO DEVELOPED OVER THE FAR
WRN QUARTER OF THE CWA ATOP A LEE TROUGH. TEMPS THUS FAR FOR MOST
LOCATIONS ARE AT OR ABOVE THE CENTURY MARK.
FOR THE REST OF THE AFTERNOON RELATIVE HUMIDITIES SHOULD CONTINUE
TO SLOWLY DECREASE ESPECIALLY ACROSS THE WRN ZONES WHERE THE RED FLAG
WARNING IS IN PLACE. THE SFC WINDS HAVE BEEN RATHER LIGHT IN THE
15 TO 25 MPH RANGE THUS FAR...SO ONLY PORTIONS OF THE WARNING ARE
VERIFYING TO THIS POINT. HAVE LEFT THE FCST DRY TODAY THROUGH
TOMORROW DESPITE THE HRRR GENERATING ISOLATED STORMS THIS
AFTERNOON ALONG/NEAR THE SFC TROUGH (WHERE THE CU IS CURRENTLY
LOCATED).
FOR TONIGHT I WENT WITH A PERSISTENCE FORECAST FOLLOWING LAST
NIGHT/S LOW TEMPS ALONG WITH LIGHT SOUTHERLY WINDS AND MOSTLY
CLEAR SKIES. TOMORROW WILL ONCE AGAIN BE HOT WITH LOW 100S ACROSS
THE BOARD...WARMEST EAST WHERE THE HEAT ADVISORY IS. HAVE DEBATED
WHETHER TO ISSUE A FIRE WEATHER WATCH FOR TOMORROW FOR GENERALLY
THE SAME LOCATIONS AS TODAY/S RED FLAG WARNING. THE FORECASTED
RELATIVE HUMIDITIES REACH CRITERIA BUT THE WINDS APPEAR A BIT TOO
LIGHT. WANT TO SEE HOW TODAY PLAYS OUT AS TODAY AND TOMORROW ARE
NEARLY IDENTICAL FOR MET CONDITIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 233 PM MDT SAT JUL 21 2012
THE STRONG H5 RIDGE REMAINS IN PLACE THROUGH MONDAY NIGHT. VERY
LITTLE CHANGES REGARDING THE AIRMASS ALOFT WITH SIMILAR HIGH TEMPS
EACH DAY THROUGH MIDWEEK. NO CHANGE TO CURRENT HEAT ADVISORY WITH
EASTERN LOCATIONS EXPECTED TO HAVE HEAT INDEX VALUES AROUND 105.
TEMPERATURES ALOFT WILL COOL SOME AFTER TUESDAY AS H5 HEIGHTS
BEGIN TO DECREASE...HOWEVER WITH RIDGING OF SOME FASHION EXPECTED
TO CONTINUE...ABOVE NORMAL TEMPERATURES IN THE UPPER 90S/NEAR 100
WILL CONTINUE THROUGH THE EXTENDED PERIODS.
DRY CONDITIONS ARE EXPECTED TO PERSIST WITH RED FLAG CONDITIONS
POSSIBLE AGAIN ON MONDAY...DEPENDING ON WINDS. BEST CHANCE FOR PRECIP
WILL BE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT WHEN A STRONG
UPPER LOW MOVES ACROSS SOUTHERN CANADA...AND A TRAILING SHORTWAVE
TROUGH MOVES ACROSS THE PLAINS. THERE REMAINS UNCERTAINTY REGARDING
THE POSITION/STRENGTH OF THE TRAINING SHORTWAVE...WITH ECMWF FURTHER
SOUTH AND STRONGER. IGNORING THE DIFFERENCES REGARDING LARGE SCALE
ASCENT...MOISTURE PROFILES ARE UNIMPRESSIVE. DEEP DRY LAYER TO 650MB
REMAINS IN PLACE THROUGH THESE PERIODS. BASED ON SOUNDINGS ISOLATED
DRY THUNDERSTORMS MAY ULTIMATELY BE FAVORED...HOWEVER WITH BOTH GFS
AND ECMWF ARE BOTH SHOWING QPF OF SOME SORT AROUND THE AREA SO
MEASURABLE PRECIP CANT BE RULED OUT. I DECIDED TO KEEP ISOLATED
THUNDERSTORM MENTION FOR NOW. RIDGING BEGINS TO BUILD BACK OVER THE
INTER-MOUNTAIN WEST ON THURSDAY AND SHOULD CONTINUE TO DOMINATE THE
WEATHER OVER THE PLAINS THROUGH NEXT WEEKEND. THERE IS SOME
INDICATION OF A SHORTWAVE TROUGH PASSAGE NEXT WEEKEND OVER EASTERN
NEBRASKA...HOWEVER MOISTURE SEEMS TO BE CUT OFF FROM OUR AREA. WITH
STABLE AIR MASS ALOFT OVER OUR CWA..CONFIDENCE IS LOW IN ANY
ACTIVITY INITIATING OVER OUR CWA...SO I KEPT FORECAST DRY AFTER
WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 541 PM MDT SAT JUL 21 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WINDS WILL BE
GUSTY...ESPECIALLY AT KGLD...WHEN THE HEATING OF THE DAY OCCURS.
&&
.CLIMATE...
ISSUED AT 233 PM MDT SAT JUL 21 2012
VERY HOT TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH NEXT
WEEK...WITH SEVERAL LOCATIONS POSSIBLY BREAKING DAILY TEMPERATURE
RECORDS.
DAILY RECORDS FOR SUNDAY (JUL 22)...
GOODLAND.....105 (1934)
HILL CITY....108 (1934)
BURLINGTON...104 (1990)
MCCOOK.......110 (1931)
YUMA.........109
TRIBUNE......107
COLBY........107
DAILY RECORDS FOR MONDAY (JUL 23)...
GOODLAND.....110 (1936)
HILL CITY....107 (1940)
BURLINGTON...105 (1963)
MCCOOK.......106 (1940)
YUMA.........107
TRIBUNE......107
COLBY........105
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR
KSZ001-002-013-014-027-041.
HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR KSZ002>004-014>016-028-
029-042.
CO...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ252>254.
NE...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR
NEZ079-080.
HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR NEZ080-081.
&&
$$
SHORT TERM...05
LONG TERM...DR
AVIATION...BULLER
CLIMATE...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
313 PM MDT FRI JUL 20 2012
.SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 112 PM MDT FRI JUL 20 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE ACROSS THE
INTER-MOUNTAIN WEST...CENTERED OVER EASTERN COLORADO. AT THE
SURFACE A WEAK SURFACE TROUGH IS IN PLACE WITH ITS MAIN AXIS ALONG
THE FRONT RANGE. SEVERAL WEAK SURFACE TROUGHS EXTEND EAST TOWARDS
THE KS CO BORDER.
WEAK SURFACE CONVERGENCE ALONG THESE SURFACE TROUGHS AND STEEP LOW
LEVEL LAPSE RATES HAVE LED TO THE DEVELOPMENT OF SHALLOW CUMULUS
EARLY THIS AFTERNOON. LARGE SCALE SUBSIDENCE COMBINED WITH A VERY
STRONG CAP WILL LIMIT UPDRAFT POTENTIAL...SO I HAVE KEPT ANY
THUNDERSTORM MENTION OUT OF FORECAST THROUGH TOMORROW.
WITH DRY CONDITIONS EXPECTED MAIN CONCERN IS NEAR RECORD
TEMPERATURES AND POSSIBLE FIRE WEATHER CONCERNS. WITH GUIDANCE
SHOWING AIRMASS SLIGHTLY ALOFT THAN TODAY...AND WINDS SHIFTING TO
THE SOUTH-SOUTHWEST TEMPERATURES ACROSS MUCH OF THE AREA COULD SEE
TEMPERATURES IN THE 105 TO 110 RANGE. RED FLAG CONDITIONS ARE NOT
CURRENTLY EXPECTED...WITH WINDS AROUND 20 MPH. IF RH VALUES WERE
TO DROP TO 10 PERCENT IN THE WEST THEN WE COULD MEET CRITERIA.
THIS IS NOT EXPECTED TO OCCUR...SO NO FIRE WEATHER HIGHLIGHTS
PLANNED FOR SATURDAY AT THIS POINT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 313 PM MDT FRI JUL 20 2012
BROAD MID/UPPER RIDGE WILL REMAIN ANCHORED OVER THE CENTRAL PLAINS
THROUGH THE EARLY PART OF NEXT WEEK WITH A CONTINUATION OF
AFTERNOON TEMPS IN THE 100 TO 110 RANGE WITH APPARENT TEMPS
GENERALLY IN THE 103 TO 108 RANGE. AS SUCH...HAVE EXTENDED THE
HEAT ADVISORY THROUGH TUESDAY EVENING. HAD CONSIDERED UPGRADING AT
LEAST FAR EASTERN PORTIONS OF THE FORECAST AREA TO AN EXCESSIVE
HEAT WARNING GIVEN SLIGHTLY HIGHER HEAT INDICIES BUT THERE IS A
BIT OF UNCERTAINTY AS TO HOW FAR DEW POINTS WILL MIX EACH
AFTERNOON. IF THEY ARE LOWER THAN CURRENTLY FORECAST...APPARENT
TEMP VALUES WOULD BE CORRESPONDINGLY LOWER. FELT MORE CONFIDENT IN
KEEPING THE ADVISORY IN PLACE AND ALLOW FUTURE SHIFTS TO
REEVALUATE THE NEED FOR AN UPGRADE.
WEAK SHORTWAVE TROUGH WILL PASS THROUGH THE TRI-STATE AREA TUESDAY
NIGHT INTO WEDNESDAY. STRONGEST FORCING FOR ASCENT WILL REMAIN
NORTH OF THE FORECAST AREA BUT CAN`T COMPLETELY RULE OUT AN
ISOLATED/SCATTERED STORM. POTENTIAL FOR ISOLATED CONVECTION WILL
CONTINUE EACH AFTERNOON THROUGH THE END OF THE FORECAST PERIOD. TEMPS
WILL BE ONLY SLIGHTLY COOLER WITH HIGHS RANGING FROM THE MID 90S
TO AROUND 105 FROM WEST TO EAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1100 AM MDT FRI JUL 20 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT BOTH KGLD AND
KMCK. SOUTHEAST WINDS AROUND 11KT WILL PERSIST THROUGH
TONIGHT...WITH GUSTS THIS AFTERNOON AND EARLY EVENING 15-18KT. LEE
TROUGH STRENGTHENS SOME OVER EASTERN COLORADO...WITH GRADIENT
INCREASING SOME OVER BOTH TERMINALS. RESULT WILL BE WINDS SHIFTING
TO THE SOUTH...WITH GUSTY WINDS AROUND 18KT DEVELOPING AFTER
SUNRISE SATURDAY MORNING.
&&
.CLIMATE...
ISSUED AT 112 PM MDT FRI JUL 20 2012
VERY HOT TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH NEXT
WEEK...WITH SEVERAL LOCATIONS POSSIBLY BREAKING A DAILY
TEMPERATURE RECORD ON SATURDAY AND SUNDAY.
DAILY RECORDS FOR SATURDAY (JUL 21)...
GOODLAND.....105 (2005)
HILL CITY....110 (1934)
BURLINGTON...103 (2005)
MCCOOK.......105 (2005)
YUMA.........109
TRIBUNE......107
COLBY........106
DAILY RECORDS FOR SUNDAY (JUL 22)...
GOODLAND.....105 (1934)
HILL CITY....108 (1934)
BURLINGTON...104 (1990)
MCCOOK.......110 (1931)
YUMA.........109
TRIBUNE......107
COLBY........107
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR KSZ002>004-014>016-028-
029-042.
CO...NONE.
NE...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR NEZ080-081.
&&
$$
SHORT TERM...DR
LONG TERM...FOLTZ
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
112 PM MDT FRI JUL 20 2012
.SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 112 PM MDT FRI JUL 20 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE ACROSS THE
INTER-MOUNTAIN WEST...CENTERED OVER EASTERN COLORADO. AT THE
SURFACE A WEAK SURFACE TROUGH IS IN PLACE WITH ITS MAIN AXIS ALONG
THE FRONT RANGE. SEVERAL WEAK SURFACE TROUGHS EXTEND EAST TOWARDS
THE KS CO BORDER.
WEAK SURFACE CONVERGENCE ALONG THESE SURFACE TROUGHS AND STEEP LOW
LEVEL LAPSE RATES HAVE LED TO THE DEVELOPMENT OF SHALLOW CUMULUS
EARLY THIS AFTERNOON. LARGE SCALE SUBSIDENCE COMBINED WITH A VERY
STRONG CAP WILL LIMIT UPDRAFT POTENTIAL...SO I HAVE KEPT ANY
THUNDERSTORM MENTION OUT OF FORECAST THROUGH TOMORROW.
WITH DRY CONDITIONS EXPECTED MAIN CONCERN IS NEAR RECORD
TEMPERATURES AND POSSIBLE FIRE WEATHER CONCERNS. WITH GUIDANCE
SHOWING AIRMASS SLIGHTLY ALOFT THAN TODAY...AND WINDS SHIFTING TO
THE SOUTH-SOUTHWEST TEMPERATURES ACROSS MUCH OF THE AREA COULD SEE
TEMPERATURES IN THE 105 TO 110 RANGE. RED FLAG CONDITIONS ARE NOT
CURRENTLY EXPECTED...WITH WINDS AROUND 20 MPH. IF RH VALUES WERE
TO DROP TO 10 PERCENT IN THE WEST THEN WE COULD MEET CRITERIA.
THIS IS NOT EXPECTED TO OCCUR...SO NO FIRE WEATHER HIGHLIGHTS
PLANNED FOR SATURDAY AT THIS POINT.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 225 AM MDT FRI JUL 20 2012
THE RIDGE WILL CONTINUE OVER THE PLAINS. A FRONT EXTENDING ACROSS
NORTHERN NEBRASKA INTO EASTERN WYOMING WILL SHIFT SOUTH INTO
NORTHWEST KANSAS WEDNESDAY/THURSDAY. UNTIL THEN SUBSIDENCE AND VERY
WARM TEMPERATURES ALOFT WILL INHIBIT THUNDERSTORMS ACROSS THE FA.
THE RIDGE FLATTENS SOME TUESDAY NIGHT AS AN UPPER LOW MOVES ACROSS
SOUTHERN CANADA. THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS NEAR
THE FRONT TUESDAY NIGHT. MORE STORMS WILL BE POSSIBLE
WEDNESDAY/THURSDAY.
MAX TEMPERATURES WILL CONTINUE TOPPING OUT IN THE UPPER 90S/LOW 100S
COOLING TO THE MID 90S THURSDAY. MIN TEMPERATURES WILL RANGE FROM
THE UPPER 60S IN EASTERN COLORADO TO THE MID 70S IN THE EASTERN FA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1100 AM MDT FRI JUL 20 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT BOTH KGLD AND
KMCK. SOUTHEAST WINDS AROUND 11KT WILL PERSIST THROUGH
TONIGHT...WITH GUSTS THIS AFTERNOON AND EARLY EVENING 15-18KT. LEE
TROUGH STRENGTHENS SOME OVER EASTERN COLORADO...WITH GRADIENT
INCREASING SOME OVER BOTH TERMINALS. RESULT WILL BE WINDS SHIFTING
TO THE SOUTH...WITH GUSTY WINDS AROUND 18KT DEVELOPING AFTER
SUNRISE SATURDAY MORNING.
&&
.CLIMATE...
ISSUED AT 112 PM MDT FRI JUL 20 2012
VERY HOT TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH NEXT
WEEK...WITH SEVERAL LOCATIONS POSSIBLY BREAKING DAILY TEMPERATURE
RECORD ON SATURDAY AND SUNDAY.
DAILY RECORDS FOR SATURDAY (JUL 21)...
GOODLAND.....105 (2005)
HILL CITY....110 (1934)
BURLINGTON...103 (2005)
MCCOOK.......105 (2005)
YUMA.........109
TRIBUNE......107
COLBY........106
DAILY RECORDS FOR SUNDAY (JUL 22)...
GOODLAND.....105 (1934)
HILL CITY....108 (1934)
BURLINGTON...104 (1990)
MCCOOK.......110 (1931)
YUMA.........109
TRIBUNE......107
COLBY........107
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...HEAT ADVISORY UNTIL 9 PM CDT SUNDAY FOR KSZ002>004-014>016-028-
029-042.
CO...NONE.
NE...HEAT ADVISORY UNTIL 9 PM CDT SUNDAY FOR NEZ080-081.
&&
$$
SHORT TERM...DR
LONG TERM...FS
AVIATION...DR
CLIMATE...DR
AS WITH PREVIOUS FORECAST DISCUSSIONS...IT LOOKS AS THOUGH AN
ACTIVE WEATHER PATTERN WILL DEVELOP TUE AND LAST INTO WED AS A
SERIES OF SHRTWV/S AND A STRONG THERMAL GRADIENT DEVELOPS ALONG
THE MN/IA BORDER. DUE TO HIGH PRECIPITABLE WATER VALUES...THERE
SHOULD BE SEVERAL ROUNDS OF HEAVY RAINFALL SOMETIME
TUE/WED...BEFORE TAPERING OFF LATE WED/THU AS THE COOLER AND DRIER
AIR FILTERS SOUTHWARD ACROSS THE UPPER MIDWEST. ONE DIFFERENCE IN
THE EXTENDED PERIOD IS THE ORIENTATION OF THE MAIN JET
STREAM...WHICH HAS BEEN WELL NORTH ACROSS OUR REGION. AS THE
STRONGER SYSTEM MOVES ACROSS THE AREA THU...THE PATTERN BEGINS TO
CHG WITH THE JET SAGGING SOUTHWARD BY THE END OF THE WEEK.
ALTHOUGH THICKNESS VALUES DUE BEGIN TO RISE BY LATE NEXT
WEEKEND...THE MEAN FLOW IS MUCH FASTER ACROSS THE UPPER
MIDWEST...WITH THE JET STREAM FURTHER SOUTH THAN IN PREVIOUS
WEEKS. SO...A MORE ACTIVE WEATHER PATTERN IS BECOMING MORE LIKELY
NEXT WEEK /THE BEGINNING OF AUGUST/ ALONG WITH MORE SEASONABLE
TEMPS. ..JLT..
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN CONCERN THIS TAF PERIOD DEALS WITH EVOLUTION OF CONVECTION
OVERNIGHT. THIS CONVECTION IS SITTING ON THE NOSE OF A LLJ AND
FULLY EXPECT THIS ACTIVITY FOLLOW THIS FORCING FEATURE ACROSS THE
AREA. SEEING TWO CAMPS FOR THE EVOLUTION OF THE LLJ OVERNIGHT.
THE GFS/SREF SHOW THE LLJ BASICALLY LAYING OVER ALMOST DUE EAST
OVERNIGHT...TAKING BULK OF ACTIVITY SOUTH OF ALL BUT RWF.
NAM/ECMWF/RAP SHOW THE LLJ COMING A BIT FARTHER NORTH BEFORE
TURNING EAST...ALLOWING FOR THE CONVECTIVE POTENTIAL TO WORK INTO
MSP AND POSSIBLY EVEN AS FAR NORTH AND EAST AS RNH. WITH THE HRRR
SUPPORTING THE LATER SOLUTION...CONTINUED THE MENTION OF SHRA AT
MSP AFTER 10Z. AS WITH THE PAST COUPLE OF NIGHTS...ANY CONVECTION
OUT THERE SHOULD QUICKLY DIMINISH AFTER 15Z AS LLJ WEAKENS AND
SHIFTS EAST. ANY CONVECTION THIS AFTERNOON SHOULD BE CONFINED TO
ERN WI AND THE ARROWHEAD WHERE BETTER LOW LEVEL FORCING WILL
RESIDE. FOR TONIGHT...ALL MODELS CONTINUE TO SHOW A BRIEF BREAK
FROM THE NOCTURNAL LLJ...SO NOT ANTICIPATING A THIRD NIGHT IN A
ROW OF OVERNIGHT CONVECTION.
OTHER CONCERN FOR THE REST OF THIS EVENING WILL BE THE FOG
POTENTIAL...ESPECIALLY IN WI. SFC HIGH IS CURRENTLY CENTERED OVER
THE MI/WI BORDER. DEWPOINT DEPRESSIONS GENERALLY 3 DEGREES OR
LESS...AND WITH CALM WINDS AND CURRENTLY A MOSTLY CLEAR SKY...FG
COULD BE AN ISSUE /SEE 1/2SM VIS AT RPD/. HOWEVER...CLOUD COVER
STREAMING IN FROM THE WEST SHOULD HELP LIMIT THE FOG. IS A LOW
CONFIDENCE FOG SITUATION THERE...SO WILL CONTINUE TO MONITOR FOR
POSSIBLE AMDS THROUGH THE EVENING.
KMSP...BASED ON REASONING ABOVE...DO EXPECT A BAND OF SHRA/TSRA TO
MOVE ACROSS THE FIELD IN THE 11-13Z WINDOW. WILL BE TROPICAL TYPE
SHOWERS WITH THIS ACTIVITY...SO IFR VSBYS WILL POSSIBLE IF A CORE
DOES GO OVER THE FIELD...OTHERWISE ITS VFR CONDS FOR THIS TAF
PERIOD. AS WITH YESTERDAY...WILL SEE A RAPID IMPROVEMENT IN SKY
CONDITIONS IN THE MORNING...WITH MOSTLY SUNNY SKIES BY THE
AFTERNOON. FOR WINDS...WEAK SFC LOW CURRENTLY OVER SE SODAK IS
PEGGED BY THE HRRR TO MOVE INTO SW MN THIS MORNING...WITH GRADIENT
TIGHTENING THIS MORNING. NET RESULT OF THIS WOULD BE TO CREATE A
BIT STRONGER SOUTH WIND THAN CURRENTLY INDICATED. EXTREME CASE FOR
WINDS TODAY WOULD BE A 18012G21KT TYPE WIND AT 18Z...AS NAM BUFR
SOUNDING WOULD INDICATE.
//OUTLOOK...
MONDAY...VFR EXPECTED. WINDS LGT/VRB BECOMING N 5 KT.
MONDAY NIGHT THROUGH WEDNESDAY...MVFR CONDITIONS POSSIBLE DUE TO
SCATTERED SHRA/TSRA. WINDS NE TO E 5-10 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
105 AM CDT SUN JUL 22 2012
.UPDATE...
06Z AVIATION ADDED BELOW.
&&
.DISCUSSION...
/ISSUED 223 PM CDT SAT JUL 21 2012/
THE 00Z AND 12Z ECMWF GIVE SOME HINTS OF A POSSIBLE CHANGE IN THE
LARGE SCALE PATTERN BY NEXT WEEKEND... BUT THERE IS FAR FROM A
CONSENSUS IN THE LONG RANGE GUIDANCE. THE GFS AND MANY OF THE GEFS
AND ECMWF ENSEMBLE SOLUTIONS... AS WELL AS THE CANADIAN...
CONTINUE TO HANG ONTO THE BASIC THEME OF MAINTAINING A BROAD UPPER
RIDGE OVER MUCH OF THE CENTRAL CONUS AND SOUTH CENTRAL CANADA
THROUGH THE FORESEEABLE FUTURE. SHOULD THE ECMWF PAN OUT... WE
WOULD SEE RIDGING RETROGRADE A BIT TO THE WESTERN SIDE OF THE
CONTINENT... WITH GOOD TROUGHING OVER EASTERN CANADA HELPING TO
BRING MORE CONSISTENT NEAR AND PERHAPS BELOW NORMAL TEMPERATURES
INTO OUR VICINITY. WE STILL LOOK TO BE NEAR THE PERIPHERY OF THE
UPPER RIDGE THROUGH MOST OF THE UPCOMING WEEK REGARDLESS OFF
WHETHER A SHIFT EVENTUALLY OCCURS... AND AS SUCH WILL CONTINUE TO
SEE WARM TEMPERATURES BALANCED WITH PERIODIC CHANCES FOR SHRA/TSRA
AS THE BAROCLINIC ZONE FLIRTS WITH OUR AREA.
TONIGHT AND SUNDAY...WEAK SFC FRONT EXTENDING E-W OVER CENTRAL MN
INTO NRN WI WILL CONTINUE TO DRIFT S OVERNIGHT INTO SUN...EVENTUALLY
SETTLING NEAR OR JUST S OF THE IA/MN BORDER INTO SRN WI. MOST OF THE
SHWRS/TSTMS AHEAD OF THIS FRONT OVER SRN MN HAS DISSIPATED AND
SHIFTED OFF TO THE S. CLOUDS HAVE THINNED OUT OVER MUCH OF
NRN-CENTRAL PORTIONS OF THE COVERAGE AREA AND THIS TREND WILL
CONTINUE TONIGHT AS THE FRONT MOVES S. MOST LOCATIONS WILL END UP
MOSTLY CLEAR TNGT. THE ONLY EXCEPTION WILL BE FAR SRN MN IN CLOSE
PROXIMITY TO THE FNT WHERE ISOLD SHWRS/TSTMS ARE STILL POSSIBLE.
EVEN WITH THE FNT DROPPING S...VIRTUALLY NO CHANGE IN AIRMASS IS
EXPECTED TNGT SO WITH WINDS GOING LIGHT TO CALM...NO TEMP ADVECTION
IS EXPECTED. THEREFORE...WILL LOOK FOR LOWS SUN MORNING SIMILAR TO
WHAT WAS RECORDED THIS MORNING...IN THE LOWER 60S TO LOWER 70S. HIGH
TEMPS ON SUN COULD BE A LITTLE TRICKY DEPENDING ON THE EXTENT OF
CLOUD COVER. UNDER FULL SUN AND MIXING...HIGHS COULD EASILY REACH
THE MID 90S WITH 850-925MB TEMPS FORECAST TO BE HIGHER SUNDAY THAN
TDA...AND AREAS WITHOUT CLOUDS TDA HAVE ALREADY HIT THE MID 80S.
HOWEVER...S AND SE PORTIONS OF THE CWFA WILL SEE ADDITIONAL CLOUD
COVER THAN THE REST OF THE CWFA...LEADING TO SLIGHTLY COOLER TEMPS.
THAT SAID...AM STILL LOOKING FOR HIGHS ARND 90 DEGREES...ESPECIALLY
AS WINDS SWING AROUND TO HAVE A MORE PRONOUNCED SLY COMPONENT.
TOMORROW NIGHT AND MONDAY LOOK LIKE THEY SHOULD BE WARM AND DRY
OVER MOST OF THE AREA... ALTHOUGH SOME PCPN COULD SNEAK INTO THE
SOUTH AND SOUTHWEST ON MONDAY AS ANOTHER SHORTWAVE WORKS AROUND
THE UPPER RIDGE AND INTERACTS WITH THE STALLED FRONTAL BOUNDARY.
THE TRICK OF COURSE WILL CONTINUE TO BE FIGURING OUT EXACTLY WHERE
THAT BOUNDARY WILL BE... AND SINCE EACH ROUND OF MCS AND
ASSOCIATED SHRA/TSRA CAN SHIFT ITS LOCATION... THE CHANCES ON
MONDAY COULD BE FARTHER NORTH... SOUTH... OR EAST. BUT FOR NOW...
THE CONSENSUS OPINION FROM THE ECMWF... NAM... AND SREF WOULD BE
TO HIGHLIGHT SOME POTENTIAL OVER THE SOUTHWEST INTO THE SOUTH
CENTRAL PORTION OF THE AREA... BEGINNING ON MONDAY THEN SHIFTING
OVER MUCH OF THE AREA MONDAY NIGHT INTO TUESDAY NIGHT AS A MORE
SIGNIFICANT SHORTWAVE WORKS IN AND THE FRONTAL BOUNDARY BECOMES
MORE ACTIVE. THERE MAY BE SOME POTENTIAL FOR HEAVY RAIN GIVEN THE
POSSIBILITY OF TRAINING PCPN MONDAY NIGHT THROUGH TUESDAY... BUT
IT/S DEFINITELY TOO EARLY TO PIN DOWN THAT POSSIBILITY BOTH FROM
AND OCCURRENCE AND PARTICULARLY FROM A LOCATION PERSPECTIVE.
HOWEVER... IT WILL BE SOMETHING TO KEEP AN EYE ON OVER THE NEXT
DAY OR TWO... SINCE IT MIGHT NEED TO BE HIGHLIGHTED IN LATER
FORECASTS AND OUTLOOK PRODUCTS. THE POTENTIAL COULD CERTAINLY
PERSIST THROUGH INTO WEDNESDAY NIGHT SINCE THE OVERALL BIG PICTURE
CHANGES LITTLE... UNTIL WE EVENTUALLY SEE A SUFFICIENTLY
SIGNIFICANT UPPER WAVE ARRIVE BY THURSDAY TO SHIFT THINGS OUT OF
HERE FOR A TIME. HOWEVER... THE PREDICTABILITY OF THE BOUNDARY
POSITION AND INSTABILITY/MOISTURE AXIS DECREASES MARKEDLY AFTER
TUESDAY NIGHT SINCE MUCH WILL DEPEND ON HOW THINGS EVOLVE MONDAY
NIGHT AND TUESDAY... AND AS A RESULT THE NWP SOLUTIONS VARY QUITE
A BIT BY MID-WEEK WITH RESPECT TO THE DETAILS. BUT... IF WE MANAGE
TO MAINTAIN THE UPPER RIDGE AND BAROCLINIC ZONE IN A REASONABLY
SIMILAR LOCATION THROUGH MIDWEEK... SOME LOCATIONS COULD
DEFINITELY SEE SOME SIGNIFICANT THREE OR FOUR DAY PCPN TOTALS. THE
MOST LIKELY AREA AT THIS POINT IN TIME... BASED ON MODEL CONSENSUS
OF THE LARGE SCALE MASS/MOISTURE FIELDS AND PERSISTENCE... WOULD
BE NEAR THE I-94 CORRIDOR.
KEPT CHANCES FOR PCPN IN FOR THURSDAY AS THE MAIN UPPER WAVE
FINALLY WORKS THROUGH THE REGION AND PUSHES THE BAROCLINIC ZONE
SOUTH/EAST OF US. ALSO LINGERED SOME CHANCES INTO FRIDAY OVER THE
EASTERN PORTION OF THE CWFA WHERE A SECONDARY COLD FRONTAL
BOUNDARY MAY HAVE ENCOUNTER ENOUGH LINGERING INSTABILITY TO KICK
OFF SOME SHRA/TSRA GIVEN THE PRESENCE OF THE COOLER TEMPERATURES
ALOFT. DRIED THINGS OUT FOR FRIDAY NIGHT AND SATURDAY WITH THE
EXPECTATION OF A SURFACE HIGH AND SOME COOL/DRY ADVECTION FROM THE
NORTH. OVERALL... CONFIDENCE IN THE FORECAST DETAILS DECREASES
MARKEDLY AFTER TUESDAY... SO IDEAS BY FRIDAY AND SATURDAY SHOULD
REALLY BE TAKEN WITH THAT IN MIND. HOWEVER... THERE IS A
REASONABLE CONSENSUS IN THE OVERALL IDEA OF PUSHING THE BAROCLINIC
ZONE OUT OF THE AREA DURING THE SECOND HALF OF THE WEEK... ITS
JUST A QUESTION OF WHEN AND HOW FAR. AFTER THAT... IT BECOMES A
QUESTION OF WHETHER IT WILL BE GONE FOR A WHILE AS SUGGESTED BY
THE ECMWF OR WHETHER IT WILL REASSERT ITSELF QUICKLY AS SUGGESTED
BY THE GFS.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN CONCERN THIS TAF PERIOD DEALS WITH EVOLUTION OF CONVECTION
OVERNIGHT. THIS CONVECTION IS SITTING ON THE NOSE OF A LLJ AND
FULLY EXPECT THIS ACTIVITY FOLLOW THIS FORCING FEATURE ACROSS THE
AREA. SEEING TWO CAMPS FOR THE EVOLUTION OF THE LLJ OVERNIGHT.
THE GFS/SREF SHOW THE LLJ BASICALLY LAYING OVER ALMOST DUE EAST
OVERNIGHT...TAKING BULK OF ACTIVITY SOUTH OF ALL BUT RWF.
NAM/ECMWF/RAP SHOW THE LLJ COMING A BIT FARTHER NORTH BEFORE
TURNING EAST...ALLOWING FOR THE CONVECTIVE POTENTIAL TO WORK INTO
MSP AND POSSIBLY EVEN AS FAR NORTH AND EAST AS RNH. WITH THE HRRR
SUPPORTING THE LATER SOLUTION...CONTINUED THE MENTION OF SHRA AT
MSP AFTER 10Z. AS WITH THE PAST COUPLE OF NIGHTS...ANY CONVECTION
OUT THERE SHOULD QUICKLY DIMINISH AFTER 15Z AS LLJ WEAKENS AND
SHIFTS EAST. ANY CONVECTION THIS AFTERNOON SHOULD BE CONFINED TO
ERN WI AND THE ARROWHEAD WHERE BETTER LOW LEVEL FORCING WILL
RESIDE. FOR TONIGHT...ALL MODELS CONTINUE TO SHOW A BRIEF BREAK
FROM THE NOCTURNAL LLJ...SO NOT ANTICIPATING A THIRD NIGHT IN A
ROW OF OVERNIGHT CONVECTION.
OTHER CONCERN FOR THE REST OF THIS EVENING WILL BE THE FOG
POTENTIAL...ESPECIALLY IN WI. SFC HIGH IS CURRENTLY CENTERED OVER
THE MI/WI BORDER. DEWPOINT DEPRESSIONS GENERALLY 3 DEGREES OR
LESS...AND WITH CALM WINDS AND CURRENTLY A MOSTLY CLEAR SKY...FG
COULD BE AN ISSUE /SEE 1/2SM VIS AT RPD/. HOWEVER...CLOUD COVER
STREAMING IN FROM THE WEST SHOULD HELP LIMIT THE FOG. IS A LOW
CONFIDENCE FOG SITUATION THERE...SO WILL CONTINUE TO MONITOR FOR
POSSIBLE AMDS THROUGH THE EVENING.
KMSP...BASED ON REASONING ABOVE...DO EXPECT A BAND OF SHRA/TSRA TO
MOVE ACROSS THE FIELD IN THE 11-13Z WINDOW. WILL BE TROPICAL TYPE
SHOWERS WITH THIS ACTIVITY...SO IFR VSBYS WILL POSSIBLE IF A CORE
DOES GO OVER THE FIELD...OTHERWISE ITS VFR CONDS FOR THIS TAF
PERIOD. AS WITH YESTERDAY...WILL SEE A RAPID IMPROVEMENT IN SKY
CONDITIONS IN THE MORNING...WITH MOSTLY SUNNY SKIES BY THE
AFTERNOON. FOR WINDS...WEAK SFC LOW CURRENTLY OVER SE SODAK IS
PEGGED BY THE HRRR TO MOVE INTO SW MN THIS MORNING...WITH GRADIENT
TIGHTENING THIS MORNING. NET RESULT OF THIS WOULD BE TO CREATE A
BIT STRONGER SOUTH WIND THAN CURRENTLY INDICATED. EXTREME CASE FOR
WINDS TODAY WOULD BE A 18012G21KT TYPE WIND AT 18Z...AS NAM BUFR
SOUNDING WOULD INDICATE.
//OUTLOOK...
MONDAY...VFR EXPECTED. WINDS LGT/VRB BECOMING N 5 KT.
MONDAY NIGHT THROUGH WEDNESDAY...MVFR CONDITIONS POSSIBLE DUE TO
SCATTERED SHRA/TSRA. WINDS NE TO E 5-10 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/MPG
AREA FORECAST DISCUSSION
NWS RALEIGH NC
210 AM EDT SUN JUL 22 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCES TRACKING SOUTHEAST INTO A MOIST AND
UNSTABLE AIRMASS OVER THE REGION WILL RESULT IN SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS AGAIN THIS AFTERNOON AND EVENING.
WARMER TEMPERATURES AND DAILY CHANCES FOR AFTERNOON SHOWERS AND
THUNDERSTORMS ARE EXPECTED THROUGH MUCH OF THE UPCOMING WORK WEEK IN
ASSOCIATION WITH A PERSISTENT PATTERN OF NORTHWEST FLOW ALOFT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 PM SATURDAY...
DPVA ASSOCIATED WITH AN ELONGATING SHEAR AXIS APPROACHING FROM THE
NORTHWEST AND A COUPLE SUBTLE DISTURBANCES NOTED IN WATER VAPOR
IMAGERY AND RUC 500MB ANALYSIS... ARE HELPING TO SUSTAIN CONVECTION
ALONG VARIOUS OUTFLOWS AND PRESUMABLY THE ORIGINAL WEAK COLD FRONT
NEAR THE VA BORDER EARLIER THIS AFTERNOON. THE APPROACH OF THE
UPPER LEVEL SHEAR AXIS AND MERGING COLD POOLS APPEARS TO BE HELPING
TO PUSH THE FRONT SOUTHWARD TOWARD THE US HWY 64 CORRIDOR...WHERE
ONGOING THUNDERSTORMS CURRENTLY STRETCH FROM NEAR ASHEBORO TO
RALEIGH TO THE ROCKY MOUNT AREA. WHILE MUCH OF THE CWA HAS BEEN
STABILIZED BY CONVECTION DURING THE PAST 6 HOURS...PW IS STILL
AROUND 2 INCHES AND THE SPC MESOANALYSIS SHOWS AN AXIS OF MLCAPE
EXTENDING FROM THE SOUTHERN PIEDMONT TO THE SANDHILLS....WHICH
SHOULD SUPPORT SCATTERED SHOWERS AND STORMS INTO THE OVERNIGHT
HOURS. MOST OF THE OPERATIONAL MODELS KEEP CONVECTION GOING THROUGH
12Z WHILE THE SHEAR AXIS MOVES ACROSS THE AREA...WITH MOST QPF
SHIFTING TOWARD THE COAST. THE SEVERE THREAT...WHICH HAS BEEN
LIMITED TO JUST A FEW STORMS THIS EVENING...WILL ALSO BE ON DOWNWARD
TREND AS INSTABILITY WANES. RAINFALL WAS RATHER HEAVY THIS EVENING
WITH A FEW AREAS RECEIVING 2-4 INCHES...ESPECIALLY OVER THE NORTHERN
COASTAL PLAIN...SO THERE MAY BE SOME PATCHY FOG LATE TONIGHT. THE
HRRR AND RUC RH CROSS-SECTIONS SUGGEST STRATUS WILL REDEVELOP BY
09Z...AND THERE ARE SIGNS OF STRATUS ALREADY DEVELOPING NORTH OF THE
NC/VA BORDER. LOWS SHOULD HOLD IN THE LOW TO MID 70S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 210 AM SUNDAY...
THE MODELS ARE IN AGREEMENT IN THAT STRONG UPPER RIDGING CENTERED
OVER KS/MO WILL EXTEND EASTWARD OVER THE TENNESSEE AND OHIO VALLEYS
TO THE SOUTHEAST ATLANTIC COAST MONDAY THROUGH TUESDAY NIGHT. THE
CORE OF THE RIDGING IS FORECAST TO REMAIN OVER THE CENTRAL PLAINS
BUT EXTEND ESE ACROSS THE GULF COAST STATES MONDAY INTO MONDAY
NIGHT. MODELS THEN FORECAST ANOTHER SHORT WAVE TROUGH TO DEVELOP AND
DIVE SE FROM THE GREAT LAKES TO THE MID-ATLANTIC LATE TUESDAY AND
WEDNESDAY. THE BOTTOM LINE FOR NORTH CAROLINA... HOT AND HUMID WITH
TYPICAL SUMMERTIME WEATHER WITH THE CORE OF THE EXTREME HEAT AND
DROUGHT EXPECTED TO REMAIN WELL WEST OF OUR REGION OVER KS/MO TO
IA/IL. MONDAY AND TUESDAY SHOULD BRING THE LEAST CHANCES OF
AFTERNOON AND EVENING THUNDERSTORMS. WE WILL CARRY ONLY 20-30 POP
WITH THE HIGHEST POP EXPECTED ALONG AND EAST OF THE PIEDMONT TROUGH
(WHICH MAY BE PUSHED TO THE FAR EASTERN PIEDMONT OR WESTERN COASTAL
PLAIN AND SANDHILLS BOTH DAYS. THEREFORE... 20 POP NW AND 30 POP SE
LOOKS REASONABLE. EXPECT MOSTLY SUNNY TO PARTLY SUNNY SKIES BOTH
DAYS WITH HIGHS IN THE LOWER TO MID 90S. LOWS WILL BE IN THE LOWER
TO MID 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 210 AM SUNDAY...
THE OVERALL FLOW PATTERN ACROSS THE UNITED STATES IS FORECAST TO
CONTINUE TO REPEAT ITSELF WITH THE MEAN UPPER RIDGE EXPECTED TO BE
LOCKED OVER THE PLAINS AND ROCKIES... AND THE NORTHEAST UNITES
STATES TROUGH WILL REESTABLISH ITSELF LATE WEEK. PERIODIC
DISTURBANCES IN THE NW FLOW ALOFT WILL POSSIBLY BRING ENHANCED
CHANCES OF THUNDERSTORMS... FOLLOWED BY A STRONGER UPPER SHORT WAVE
TROUGH AGAIN LATE WEEK. ONE WAVY FRONT SHOULD MAKE A RUN AT THE
REGION AROUND WEDNESDAY... FOLLOWED BY ANOTHER STRONGER FRONT BY
LATE WEEK OR THE WEEKEND. THESE FEATURES ARE DIFFICULT TO TIME THIS
FAR OUT. FOR NOW... WE WILL MAINTAIN A CHANCE OF MAINLY AFTERNOON
AND EVENING THUNDERSTORMS WEDNESDAY THROUGH SATURDAY... WITH THE
BEST CHANCES WITH THE APPROACH OF THE AFOREMENTIONED HARD TO TIME
FEATURES AND ASSOCIATED COLD FRONTS. IT APPEARS THAT ANY FRONT WILL
CONTINUE TO HAVE A VERY DIFFICULT TIME PROVIDING ANY COOLER DRIER
AIR. HOWEVER... AND MORE IMPORTANTLY... THE FRONTS WILL CONTINUE TO
SUPPLY THE REGION WITH MUCH NEEDED DRENCHING AND COOLING
THUNDERSTORMS ON A SCATTERED BASIS. HIGHS WILL REMAIN 90-95. LOWS
70-75 WED-SAT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 150 AM SUNDAY...
24-HR TAF PERIOD:
ISOLATED SHOWER ACTIVITY WILL REMAIN POSSIBLE AT ALL TAF SITES
THROUGH THE REMAINDER OF THE MORNING. GIVEN LITTLE CHANGE IN THE
ATMOSPHERE OVER CENTRAL NC COMPARED TO THE PAST SEVERAL DAYS...
EXPECT AREAS OF IFR/LIFR CEILINGS TO DEVELOP PRIOR TO SUNRISE AND
PERSIST THROUGH MID/LATE MORNING...LIFTING TO MVFR AND EVENTUALLY
SCATTERING OUT BETWEEN 15-18Z...WITH AFTERNOON CEILINGS GENERALLY
RANGING BETWEEN 3000-4000 FT AGL. ONCE AGAIN...EXPECT SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP FROM MID/LATE
AFTERNOON THROUGH THIS EVENING AS UPPER LEVEL DISTURBANCES TRACK
THROUGH A MOIST/UNSTABLE AIRMASS OVER THE REGION. ANTICIPATE THE
MOST LIKELY TIME-FRAME FOR CONVECTION WILL BE BETWEEN 19Z THIS
AFTERNOON AND 03Z TONIGHT. THE LATEST MODEL GUIDANCE INDICATES
STRENGTHENING WEST/SW FLOW BETWEEN 1500-5000 FT AGL ADVECTING A
DRIER LOW-LEVEL AIRMASS INTO CENTRAL NC BY THE END OF THE TAF PERIOD
(06-12Z MONDAY)...AND IT APPEARS THAT IFR/LIFR CEILINGS ARE LESS
LIKELY TO DEVELOP DURING THE PRE-DAWN HOURS MONDAY MORNING.
HOWEVER...FORECAST SOUNDINGS INDICATE A 25-30 KT SOUTHWESTERLY
LOW-LEVEL JET DEVELOPING AT ~1500 FT AGL PRIOR TO SUNRISE MONDAY
MORNING IN THE PRESENCE OF LIGHT/VARIABLE SURFACE WINDS. AS A
RESULT...A SHORT PERIOD OF SOUTHWESTERLY LOW LEVEL WIND SHEAR WILL
BE POSSIBLE BETWEEN 06-12Z MONDAY MORNING.
LOOKING AHEAD:
NORTHWEST FLOW ALOFT WILL BE IN PLACE OVER THE REGION THROUGHOUT
MUCH (IF NOT ALL) OF THE UPCOMING WORK WEEK. AS A RESULT...EXPECT
DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS (MOST LIKELY
AFTERNOON/EVENING) AND A POTENTIAL FOR FOG OR LOW CEILINGS DURING
THE PRE-DAWN HOURS EACH MORNING. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF/SMITH
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
203 AM EDT SUN JUL 22 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCES TRACKING SOUTHEAST INTO A MOIST AND
UNSTABLE AIRMASS OVER THE REGION WILL RESULT IN SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS AGAIN THIS AFTERNOON AND EVENING.
WARMER TEMPERATURES AND DAILY CHANCES FOR AFTERNOON SHOWERS AND
THUNDERSTORMS ARE EXPECTED THROUGH MUCH OF THE UPCOMING WORK WEEK IN
ASSOCIATION WITH A PERSISTENT PATTERN OF NORTHWEST FLOW ALOFT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 PM SATURDAY...
DPVA ASSOCIATED WITH AN ELONGATING SHEAR AXIS APPROACHING FROM THE
NORTHWEST AND A COUPLE SUBTLE DISTURBANCES NOTED IN WATER VAPOR
IMAGERY AND RUC 500MB ANALYSIS... ARE HELPING TO SUSTAIN CONVECTION
ALONG VARIOUS OUTFLOWS AND PRESUMABLY THE ORIGINAL WEAK COLD FRONT
NEAR THE VA BORDER EARLIER THIS AFTERNOON. THE APPROACH OF THE
UPPER LEVEL SHEAR AXIS AND MERGING COLD POOLS APPEARS TO BE HELPING
TO PUSH THE FRONT SOUTHWARD TOWARD THE US HWY 64 CORRIDOR...WHERE
ONGOING THUNDERSTORMS CURRENTLY STRETCH FROM NEAR ASHEBORO TO
RALEIGH TO THE ROCKY MOUNT AREA. WHILE MUCH OF THE CWA HAS BEEN
STABILIZED BY CONVECTION DURING THE PAST 6 HOURS...PW IS STILL
AROUND 2 INCHES AND THE SPC MESOANALYSIS SHOWS AN AXIS OF MLCAPE
EXTENDING FROM THE SOUTHERN PIEDMONT TO THE SANDHILLS....WHICH
SHOULD SUPPORT SCATTERED SHOWERS AND STORMS INTO THE OVERNIGHT
HOURS. MOST OF THE OPERATIONAL MODELS KEEP CONVECTION GOING THROUGH
12Z WHILE THE SHEAR AXIS MOVES ACROSS THE AREA...WITH MOST QPF
SHIFTING TOWARD THE COAST. THE SEVERE THREAT...WHICH HAS BEEN
LIMITED TO JUST A FEW STORMS THIS EVENING...WILL ALSO BE ON DOWNWARD
TREND AS INSTABILITY WANES. RAINFALL WAS RATHER HEAVY THIS EVENING
WITH A FEW AREAS RECEIVING 2-4 INCHES...ESPECIALLY OVER THE NORTHERN
COASTAL PLAIN...SO THERE MAY BE SOME PATCHY FOG LATE TONIGHT. THE
HRRR AND RUC RH CROSS-SECTIONS SUGGEST STRATUS WILL REDEVELOP BY
09Z...AND THERE ARE SIGNS OF STRATUS ALREADY DEVELOPING NORTH OF THE
NC/VA BORDER. LOWS SHOULD HOLD IN THE LOW TO MID 70S.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 250 PM SATURDAY...
WHILE MOISTURE REMAINS PLENTIFUL OVERALL...WITH PRECIPITABLE WATER
VALUES TO AROUND TWO INCHES PARTICULARLY ON THE NAM...THE GFS BUFR
SOUNDINGS ARE NOTICEABLY MORE STABLE PARTICULARLY WITH SLIGHT
WARMING IN THE LAYER AROUND 850MB. THE SHEAR AXIS WEAKENS AND SHOULD
PIVOT WEST AND WEAKEN IN RESPONSE TO INCREASING HEIGHTS ALOFT. WHILE
OVERALL INSTABILITY APPEARS BETTER SUNDAY AFTERNOON AS OPPOSED TO
THIS AFTERNOON...WITH MLCAPE LIKELY REACHING OR JUST EXCEEDING
2000J/KG...OVERALL COVERAGE OF SHOWERS AND THUNDERSTORMS IN CENTRAL
NORTH CAROLINA IS LIKELY TO BE LESS AS A RESULT OF WHAT SHOULD BE
DIMINISHING SYNOPTIC SUPPORT. THE FRONT SHOULD CONTINUE TO SLOWLY
WEAKEN...AND WITH THE SHEAR AXIS WEAKENING AS WELL...WILL CONTINUE
THE FORECAST OF SCATTERED SHOWERS AND THUNDERSTORMS FROM THE
AFTERNOON THROUGH THE EARLY EVENING. THERE IS STILL THE POTENTIAL
FOR AN ISOLATED DAMAGING WIND THREAT...AND AGREE WITH THE SPC DAY 2
ASSESSMENT OF THAT ISOLATED POTENTIAL. DOWNDRAFT CAPE IS 500-900J/KG
AS FORECAST BY THE MORE ROBUST NAM...UNDER A RELATIVE MAXIMUM OF
850MB THETA-E. HIGH TEMPERATURES SHOULD MOSTLY BE IN THE LOWER 90S...
WITH A FEW HIGHS POSSIBLE AROUND 90 OR TOWARD 95 DEPENDING ON HOW
QUICKLY ANY MORNING LOW CLOUDS DIMINISH...AND THE ONSET OF ANY DEEP
CONVECTION.
SUNDAY NIGHT...BOTH THE NAM AND THE GFS BUFR SOUNDINGS BECOME FAIRLY
STABLE TO DEEP CONVECTION. THE GFS DOES FORECAST SOME OVERNIGHT
QPF...BUT ITS MOS GUIDANCE CHANCES OF RAIN ARE LOW LATE AT NIGHT...
AND WITH CONVERGENCE ALOFT FORECAST OVERNIGHT SUNDAY...IT WOULD SEEM
CHANCES FOR ANY SHOWERS AND THUNDERSTORMS SHOULD FALL BELOW SLIGHT
CHANCE BY AROUND MIDNIGHT. OVERNIGHT LOWS ONCE AGAIN SHOULD BE
MOSTLY IN THE RANGE OF 70 TO 75.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
THE MAIN WEATHER FEATURE DURING MUCH OF THE LONG TERM PERIOD WILL BE
BROAD MID LEVEL RIDGING THAT IS PROGGED TO EXTEND FROM THE CENTRAL
PLAINS INTO THE SOUTHEAST...WITH CENTRAL NC ON THE NORTHERN
PERIPHERY OF THIS RIDGE. THEREFORE...WE WILL BE UNDER NORTHWESTERLY
FLOW ALOFT FOR MUCH OF THE PERIOD AND HENCE THE POTENTIAL FOR WEAK
DISTURBANCES TO IMPACT THE AREA WILL LIKELY BE OUR MAIN CHANCES FOR
ANY PRECIP BEYOND TYPICAL SUMMERTIME CONVECTION. MODELS ALSO
INDICATE (TO VARYING DEGREES) A BACK DOOR FRONT APPROACHING THE AREA
MIDWEEK...BUT GIVEN THE TIME OF YEAR...WILL KEEP THE FRONT NORTH OF
REGION FOR NOW. AS A RESULT...SINCE IT IS IMPOSSIBLE TO TIME ANY
WEAK UPPER LEVEL DISTURBANCES THIS FAR OUT...AM EXPECTING MOSTLY
ISOLATED TO SCATTERED DIURNAL TYPE PRECIP AS A WEAK SURFACE TROUGH
WILL BE IN PLACE OVER THE REGION. THEN...AT THE END OF THE WORK
WEEK...A SHORT WAVE TROUGH IS PROGGED TO AMPLIFY ACROSS THE NORTHERN
PLAINS WHICH WILL EVENTUALLY SUPPRESS THE RIDGE. AS THIS SHORT WAVE
MOVES EAST AND AMPLIFIES EVEN MORE...IT SHOULD BEGIN TO CARVE AN
UPPER LEVEL TROUGH OVER THE REGION BY THE WEEKEND...WITH AN
ASSOCIATED SURFACE FRONT APPROACHING FROM THE NORTHWEST. WILL STILL
KEEP ONLY SCATTERED DIURNAL CONVECTION IN THE FORECAST FOR THIS TIME
FRAME...BUT WILL SHOW A SLIGHT INCREASE IN THE POPS. THE HEAT WILL
ALSO RETURN TO THE REGION...WITH GENERALLY MID (AND SOME UPPER) 90S
EXPECTED FOR MOST OF THE PERIOD. OVERNIGHT LOWS WILL REMAIN IN THE
LOW TO MID 70S.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 150 AM SUNDAY...
24-HR TAF PERIOD:
ISOLATED SHOWER ACTIVITY WILL REMAIN POSSIBLE AT ALL TAF SITES
THROUGH THE REMAINDER OF THE MORNING. GIVEN LITTLE CHANGE IN THE
ATMOSPHERE OVER CENTRAL NC COMPARED TO THE PAST SEVERAL DAYS...
EXPECT AREAS OF IFR/LIFR CEILINGS TO DEVELOP PRIOR TO SUNRISE AND
PERSIST THROUGH MID/LATE MORNING...LIFTING TO MVFR AND EVENTUALLY
SCATTERING OUT BETWEEN 15-18Z...WITH AFTERNOON CEILINGS GENERALLY
RANGING BETWEEN 3000-4000 FT AGL. ONCE AGAIN...EXPECT SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP FROM MID/LATE
AFTERNOON THROUGH THIS EVENING AS UPPER LEVEL DISTURBANCES TRACK
THROUGH A MOIST/UNSTABLE AIRMASS OVER THE REGION. ANTICIPATE THE
MOST LIKELY TIME-FRAME FOR CONVECTION WILL BE BETWEEN 19Z THIS
AFTERNOON AND 03Z TONIGHT. THE LATEST MODEL GUIDANCE INDICATES
STRENGTHENING WEST/SW FLOW BETWEEN 1500-5000 FT AGL ADVECTING A
DRIER LOW-LEVEL AIRMASS INTO CENTRAL NC BY THE END OF THE TAF PERIOD
(06-12Z MONDAY)...AND IT APPEARS THAT IFR/LIFR CEILINGS ARE LESS
LIKELY TO DEVELOP DURING THE PRE-DAWN HOURS MONDAY MORNING.
HOWEVER...FORECAST SOUNDINGS INDICATE A 25-30 KT SOUTHWESTERLY
LOW-LEVEL JET DEVELOPING AT ~1500 FT AGL PRIOR TO SUNRISE MONDAY
MORNING IN THE PRESENCE OF LIGHT/VARIABLE SURFACE WINDS. AS A
RESULT...A SHORT PERIOD OF SOUTHWESTERLY LOW LEVEL WIND SHEAR WILL
BE POSSIBLE BETWEEN 06-12Z MONDAY MORNING.
LOOKING AHEAD:
NORTHWEST FLOW ALOFT WILL BE IN PLACE OVER THE REGION THROUGHOUT
MUCH (IF NOT ALL) OF THE UPCOMING WORK WEEK. AS A RESULT...EXPECT
DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS (MOST LIKELY
AFTERNOON/EVENING) AND A POTENTIAL FOR FOG OR LOW CEILINGS DURING
THE PRE-DAWN HOURS EACH MORNING. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF/SMITH
SHORT TERM...DJF
LONG TERM...KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1254 AM EDT SUN JUL 22 2012
.SYNOPSIS...
TYPICAL SUMMERTIME WEATHER WILL CONTINUE WITH BERMUDA HIGH PRESSURE
OFFSHORE AND SURFACE LOW PRESSURE INLAND PRODUCING SOUTHWEST WINDS
AND LOCALIZED THUNDERSTORMS TO THE EASTERN CAROLINAS. A BUILDING
RIDGE ALOFT WILL BRING A WARMING TREND THROUGH THIS NEW WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 AM SUNDAY...PLENTY OF THICK MID-LEVEL CLOUD COVER
(ALTOCUMULUS) COVERS THE EASTERN CAROLINAS EARLY THIS MORNING. THIS
MOISTURE IS ASSOCIATED WITH A MID-LEVEL SHEAR AXIS THAT LIES JUST
EAST OF INTERSTATE 95. RADAR LOOPS SHOW SPRINKLES AND A FEW VERY
LIGHT SHOWERS MOVING WEST TO EAST. THE PAST FEW HRRR MODEL RUNS
ACTUALLY DEVELOP MORE IMPRESSIVE SHOWERS AND THUNDERSTORMS JUST
AHEAD OF THE SHEAR AXIS IN THE NEXT HOUR OR TWO. WHILE I CAN SAY I`M
NOT TOO IMPRESSED WITH THE HRRR`S DUBIOUS TRACK RECORD WITH
CONVECTIVE INITIATION OVER THE PAST WEEK...I`LL ADD SMALL POPS
(20-30 PERCENT) FROM NOW THROUGH 10Z (6 AM) MAINLY FOR THE COASTAL
COUNTIES. WITH CLOUDS AND A STEADY SW SURFACE WIND WE`RE PROBABLY
WITHIN A COUPLE DEGREES OF OUR ULTIMATE OVERNIGHT LOWS...MID 70S
INLAND AND 77-81 NEAR THE COAST. PREVIOUS DISCUSSION FROM 1030 PM
SATURDAY FOLLOWS...
LATEST SFC ANALYSIS PLACES THE STATIONARY FRONT JUST NORTH OF THE
AREA...EXTENDING FROM ROUGHLY DUCK NC WEST-SOUTHWEST TO NASHVILLE
NC. THIS KEEPS THE FA WITHIN THE JUICY AIR MASS PAINTED WITH PWS OF
2+ INCHES. THE MAJORITY OF THE DAYS CONVECTION HAS WANED ACROSS THE
AREA AND WAS LIKELY A PRODUCT FROM SFC FORCING...IE. SEA BREEZE AND
RESIDUAL OUTFLOW BOUNDARIES. MID-LEVEL TROFFINESS WILL PERSIST
TONIGHT INTO SUNDAY. A WEAK IMPULSE EMBEDDED IN 5H FLOW IS PROGGED
TO MOVE FROM GSP THIS EVENING ACROSS PORTIONS OF THE FA OVERNIGHT TO
THE SOUTHERN OUTER BANKS AFTER SUNDAYS SUNRISE. THE DYNAMICS FROM
THE IMPULSE WILL BE ENOUGH TO IGNITE ISOLATED/WIDELY SCATTERED TSRA
DURING A PORTION OF THE OVERNIGHT. AND FOR THAT REASON HAVE KEPT AN
ACTIVE OVERNIGHT POP ACROSS THE NORTHERN PORTIONS OF THE FA THROUGH
THE MID TO LATE EVENING HRS. ANOTHER WARM AND STICKY NIGHT ON TAP
FOR THE FA...WITH LOW TEMPS RANGING FROM THE MID 70S INLAND TO THE
UPPER 70S TO AROUND 80 ALONG THE IMMEDIATE COAST. THE SFC PG IS NOT
AS PRONOUNCED LIKE PREVIOUS NIGHTS. THIS WILL RESULT IN SW WINDS 5
MPH OR LESS INLAND...5 TO 15 MPH ALONG THE IMMEDIATE COAST. THE
UPPER RANGE LIMIT WILL OCCUR THIS EVENING DUE TO THE DECAY OF AN
ACTIVE SEA BREEZE CIRCULATION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...BERMUDA HIGH AND PIEDMONT TROUGH REMAIN TWO
DOMINANT SURFACE FEATURES CONTROLLING COASTAL CAROLINAS WEATHER.
THIS WILL MAINTAIN A SW SFC FLOW VEERING AROUND TO MORE WESTERLY
THROUGH THE LOW TO MID LEVELS. 850 TO 700 MB WINDS WILL BE 15 TO
25 KTS SUN AFTN INCREASING UP TO 20 TO 30 KTS MON AFTN AS THEY
VEER TOWARD THE NW. MID TO UPPER TROUGH LIFTS OFF TO THE NORTH
NORTHEAST AS RIDGE BUILDS IN FROM EAST AND WEST EXPANDING ACROSS
THE SOUTHEAST SUNDAY THROUGH MONDAY. ANY SHORTWAVE ENERGY TOPPING
THE RIDGE SHOULD REMAIN JUST TO NORTH OF LOCAL CWA. H5 HEIGHTS WILL
RISE UP TO 595 DEM AND WILL SEE INCREASED BUT WEAKER SUBSIDENCE
AND DRIER AIR THROUGH THE MID LEVELS. WITH BEST UPPER LEVEL SUPPORT
TO THE NORTH AND STRONG WESTERLY LOW TO MID LEVEL FLOW...EXPECT
MORE LOCALIZED CONVECTION ALONG CONVERGENT BOUNDARIES TYPICAL OF
SUMMERTIME...WITH BETTER CHC OVER NC. SEA BREEZE SHOULD REMAIN FAIRLY
CLOSE TO THE COAST WITH STRONGER WESTERLY COMPONENT TO
FLOW...ESPECIALLY ON MONDAY. THEREFORE ANY CONVECTION THAT FORMS
ALONG SEA BREEZE BOUNDARY WILL BE CLOSER TO THE COAST AND WILL
MOVE RAPIDLY OFF TO THE EAST TOWARD THE WATERS. ALSO EXPECT OTHER
SHWRS/TSTMS TO DEVELOP ALONG PIEDMONT TROUGH FURTHER INLAND AND
MOVE EAST TOWARD THE COAST. MOISTURE PROFILES DO SHOW VERY MOIST
UPPER LEVELS WITH WINDS ABOVE H4 HAVING GOOD NW-N COMPONENT.
THEREFORE EXPECT PERIODS OF CIRRUS...MAINLY FROM CONVECTIVE DEBRIS
CLOUDS FROM CONVECTION UPSTREAM. THIS SHOULD FILTER OUT SOME OF
THE SUN.
WITH RISING H5 HEIGHTS AND STRONG LOW LEVEL WESTERLY COMPONENT TO
THE FLOW...EXPECT WARM SUMMERTIME TEMPS RUNNING BETWEEN 90 AND 95
MOST PLACES.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...A RETURN TO HOT AND HUMID WEATHER EXPECTED
FOR MUCH OF THE EXTENDED...WITH ABOVE CLIMO PRECIP CHANCES THROUGH
LATE WEEK.
LARGE ELONGATED UPPER RIDGE EXTENDING FROM NEBRASKA SOUTHEAST INTO
FLORIDA WILL GET GRADUALLY PUSHED SOUTHWARD AS A LARGE UPPER LOW
ACROSS CANADA SHEARS OFF AND DROPS VORT IMPULSES INTO A BROAD
EASTERN LONGWAVE TROUGH. AS THIS OCCURS...W/NW FLOW DEVELOPS THROUGH
MUCH OF THE COLUMN ABOVE THE IMMEDIATE SURFACE. AT THE
SURFACE...LARGE BERMUDA HIGH PRESSURE GETS SHUNTED SOUTH AS
WELL...BUT NEAR SURFACE S/SW FLOW PERSISTS THROUGH THE PERIOD.
THE COMBINATION OF THE MID LEVEL TROUGH...850MB TEMPS AROUND
20C...AND MOIST RETURN SURFACE FLOW WILL CREATE DECENT CONVECTION
CHANCES EACH DAY...WITH WIDESPREAD COVERAGE POSSIBLE ESPECIALLY ON
WEDNESDAY. AN ACTIVE PIEDMONT TROUGH AND SEA BREEZE FRONT WILL OCCUR
EACH DAY...ALTHOUGH WITH THE DEEP W/NW FLOW THE SEA BREEZE WILL
REMAIN PINNED NEAR THE COAST. PWATS OF TWO INCHES OR GREATER AND
HIGH THETA-E AIR COMBINED WITH STEEP LOW LEVEL LAPSE RATES AND
SUBTLE VORT IMPULSES WILL SPAWN CONVECTION EACH AFTN...BUT MOST
ACTIVITY WILL BE DIURNALLY FORCED AND WILL KEEP INHERITED
CHC-BY-DAY...SILENT-BY-NIGHT POP. THE BEST TSTM COVERAGE WILL BE
WEDNESDAY AHEAD OF A COLD FRONT WHICH WILL TRY TO DROP SOUTH INTO
THE ILM CWA. EXPECT THIS BOUNDARY TO GET HUNG UP JUST NORTH OF THE
AREA...BUT THIS WILL STILL SERVE AS AN ADDITIONAL FOCUS FOR
CONVECTION DURING WED/WED NIGHT. OVERALL POP WILL TREND DOWNWARD
LATE IN THE PERIOD AS 500MB RIDGE BUILDS BACK TO THE NORTH.
HOWEVER...WILL KEEP SCHC POP (SILENT BY DAY 6/7) FOR ISOLATED TSTMS
IN A STILL VERY WARM/MOIST AIR MASS.
850MB TEMPS AROUND 20C WILL SUPPORT HIGHS WELL INTO THE 90S MOST
DAYS EVEN WITH THE LIMITING IMPACT OF CLOUD COVER. MINS AT NIGHT
WILL FALL ONLY INTO THE MID 70S...NEAR 80 SOME NIGHTS AT THE COAST.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...HRRR MODEL STILL WANTS TO DEVELOP ANOTHER ROUND OF
CONVECTION BETWEEN NOW AND 10Z. MUCH OF THE CWA ATMOSPHERE HAS NOT
BEEN WORKED OVER...SO THIS REMAINS A POSSIBILITY HOWEVER CONFIDENCE
IS RATHER LOW GIVEN THE HRRR`S DUBIOUS TRACK RECORD WITH CONVECTIVE
INITIATION OVER THE PAST WEEK. WE DO EXPECT BKN MID-LEVEL CLOUD
COVER TO REMAIN IN PLACE...WITH LIGHT SOUTHWEST SURFACE WINDS
THROUGH DAYBREAK.
AREAS THAT RECEIVED DECENT RAINFALL...MAINLY LBT...COULD SEE SOME
MVFR FOG TOWARD SUNRISE. AFTER DAYBREAK CONTINUED SOUTHWEST FLOW IS
EXPECTED...A BIT WEAKER THAN SATURDAY. LIKEWISE DEEP MOISTURE IS A
BIT LESS THAN WAS OBSERVED ON SATURDAY...BUT STILL COULD SQUEEZE OUT
ISOLATED CONVECTION IN THE AFTERNOON...MAINLY ALONG THE SEABREEZE
BOUNDARY AND PERHAPS NEAR THE PIEDMONT TROUGH AXIS INLAND.
EXTENDED OUTLOOK...CHANCE OF AFTERNOON THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 AM SUNDAY...A MODEST SOUTHWEST WIND WILL CONTINUE THROUGH
THE NIGHT AVERAGING 15 KT. A FEW GUSTS COULD APPROACH 20 KT AT
TIMES...ESPECIALLY NEAR THE TIP OF CAPE FEAR...AND OFFSHORE NORTH OF
CAPE FEAR. SEAS RANGE FROM 4 FT AT THE FRYING PAN SHOALS BUOY TO 3
FT AT THE NEARSHORE WRIGHTSVILLE BEACH CORMP BUOY...BOTH RIGHT ON
TARGET WITH OUR PREVIOUS FORECASTS. THE LATEST HRRR MODEL INDICATES
WE MAY SEE RENEWED DEVELOPMENT OF SHOWERS AND THUNDERSTORMS
OVERNIGHT...ESPECIALLY FROM MYRTLE BEACH TO SOUTHPORT. THE HRRR`S
TRACK RECORD IS NOT TOO GOOD SO WE`LL KEEP THE PROBABILITY OF NEW
SHOWERS AND STORMS IN THE "ISOLATED" CATEGORY FOR NOW. PREVIOUS
DISCUSSION FROM 1030 PM SATURDAY FOLLOWS...
THE DECAYING SEA BREEZE WILL RESULT IN SSW-SW WINDS 15 TO
OCCASIONALLY 20 KT THROUGH THIS MID-EVENING HRS ...BEFORE FINALLY
BACKING DOWN TO SW 10 TO 15 KT DURING THE PRE-DAWN HRS OF SUNDAY.
THE SFC PG WILL NOT BE NEARLY AS TIGHT LIKE THE PREVIOUS FEW
DAYS...AND THE NOCTURNAL 925MB JET IS NOT AS PRONOUNCED LIKE THE
PREVIOUS FEW DAYS. THUS...THE REASONS FOR THE LOWER FORECAST WIND
SPEEDS FOR THE OVERNIGHT INTO SUNDAY. SIG SEAS WILL RUN 2 TO 4 FT
AND BE RULED BY THE 5 TO 6 SECOND SHORT PERIOD LOCALLY PRODUCED WIND
DRIVEN WAVES. WAVEWATCH3 ILLUSTRATES AN INCREASE OF THE 9-10 SECOND
PERIOD ESE GROUND SWELL FROM 1/2 FT THIS EVENING TO 1+ FT BY SUNRISE
SUNDAY. THIS WILL OFFSET THE SUBSIDING WIND DRIVEN WAVE HEIGHTS AS A
RESULT OF THE DIMINISHING WIND FIELD.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...SOUTHWEST FLOW WILL CONTINUE BETWEEN
BERMUDA HIGH TO THE EAST AND PIEDMONT TROUGH OVER INLAND
CAROLINAS. NAM SHOWING DECENT LOW LEVEL JETTING BOTH SUN AND MON
NIGHT BUT STRONGER MON NIGHT AS WINDS ALOFT INCREASE UP TO 25 TO
30 KTS. OVERALL EXPECT SFC WINDS AROUND 15 KTS SUNDAY INCREASING
UP TO 15 TO 20 KTS ON MONDAY AND VEERING SLIGHTLY MORE TO THE
W-SW. EACH AFTERNOON WINDS WILL BECOME SLIGHTLY MORE ON SHORE AND
GUSTIER CLOSE TO THE COAST AS SEA BREEZE DEVELOPS. WNA SHOWING
LONGER PERIOD UP TO 10 SECOND SWELLS MIXING WITH LOCALLY DRIVEN
WIND WAVES TO PRODUCE SEAS 2 TO 4 FT. SHOULD REACH UP TO 4 TO 5 FT
IN OUTER WATERS MON NIGHT IN STRONGER W-SW WINDS.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...TYPICAL SUMMERTIME PATTERN THROUGH THE
EXTENDED WITH PERSISTENT SW RETURN FLOW DOMINATING THE SYNOPTIC
WIND. SW WINDS OF 15-20 KTS WILL OCCUR ON BOTH TUESDAY AND
WEDNESDAY...EASING TO AROUND 10 KTS AND VEERING TO SLIGHTLY MORE
W/SW BY THURSDAY AS A BACK DOOR TYPE FRONT APPROACHES FROM THE
NORTH. THESE SW WINDS WILL KEEP A 4-5FT/5SEC SW WIND WAVE ONGOING
THROUGH THE PERIOD...ALTHOUGH AMPLITUDE WILL DECAY SLIGHTLY ON
THURSDAY. AT THE SAME TIME...THE PERSISTENT FLOW AROUND HIGH
PRESSURE RIDGE OVER THE ATLANTIC WILL KEEP A SE GROUND SWELL PRESENT
WITHIN THE WAVE SPECTRUM. SWELL INITIALLY OF 2FT/9SEC WILL BECOME
2FT/13 SEC BY THURSDAY. SEAS OF 3-5 FT TUESDAY WILL SLOWLY
DECREASE...BECOMING 2-3 FT THURSDAY THANKS TO EASING WINDS AND THE
LONGER PERIOD SWELL DECAYING MORE QUICKLY DUE TO OCEAN BOTTOM
FRICTION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/TRA
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...HDL/TRA
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
437 AM EDT SUN JUL 22 2012
.SYNOPSIS...
A FRONTAL BOUNDARY FROM NORTH CAROLINA INTO TENNESSEE WILL
DISSIPATE TODAY. HIGH PRESSURE WILL STRETCH FROM THE CENTRAL
PLAINS TO THE SOUTHEAST COAST FROM TONIGHT INTO MONDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTH BY WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT SUNDAY...
RADAR SHOWED ISOLATED SHOWERS FROM SMYTH AND GRAYSON COUNTIES INTO
THE NORTHWEST NORTH CAROLINA MOUNTAINS. THEY REST OF THE
PRECIPITATION FROM EARLIER TONIGHT HAS EITHER DISSIPATED OR MOVD
SOUTHEAST OUT OF THE FORECAST AREA. VAD WIND PROFILES FROM AREA
RADARS SHOWED A NORTH TO NORTHEAST WIND IN THE LOWER 1-4KFT WITH
WEST WINDS ABOVE THIS LAYER. FRONT EXTENDING ACROSS NORTH CAROLINA
AND TENNESSEE WILL CONTINUE TO WEAKEN AND DISSIPATE TODAY WITH
THE WEDGE ERODING AND SURFACE WINDS BECOMING SOUTH TO SOUTHWEST
OVER THE FORECAST AREA BY MID AFTERNOON.
EXPECT LOW CLOUDS TO HOLD IN EAST OF THE BLUE RIDGE THIS MORNING.
EVEN IF COUNTIES IN THE NORTHEAST PART OF THE FORECAST AREA DO NOT
SCATTER OUT UNTIL LATER TODAY...EVEN JUST A COUPLE HOURS OF SUN
WILL BRING TEMPERATURES WELL INTO THE 80S. USED A NON DIURNAL
HOURLY TEMPERATURE FORECAST BASED ON THE GRIDDED LAMP GUIDANCE AND
EXPECTED CLOUD COVER.
FR PROBABILITY OF PRECIPITATION...MODELS HELD ON TO A LOW CHANCE
THIS MORNING. HRRR AND LOCAL WRF SHOWED SHOWERS AND THUNDERSTORMS
DEVELOPING THIS AFTERNOON SOUTH OF HWY 460. ADJUSTED TIMING AND
COVERAGE OF THE PRECIPITATION IN THE SOUTH THIS AFTERNOON.
ONCE STORMS DISSIPATE IN THE EVENING...LITTLE TO NO PRECIPITATION
EXPECTED OVERNIGHT. MAV GUIDANCE LOOKED REASONABLE FOR MINIMUM
TEMPERATURES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SUNDAY...
HEIGHTS INCREASE INTO EARLY NEXT WEEK AS A SLICE OF THE UPPER RIDGE
RESPONSIBLE FOR THE HOT WEATHER ACROSS THE HEARTLAND STRETCHES
EASTWARD. H85 TEMPS WILL RISE TO AROUND +20C. CONSIDERING THE
MOVEMENT OF THE UPPER RIDGE AND ITS POSITION BY TUESDAY ...MOVING
JUST TO OUR SW WHICH WILL DELIVER A DOWNSLOPING NW COMPONENT...TEMPS
MAY VERIFY THE WARMEST GUIDANCE VALUES. MOS HAS BEEN TOO COOL WITH
TEMPS ACROSS THE MIDWEST...AND THIS MAY CONTINUE INTO THE OHIO
VALLEY AND MIDDLE ATLANTIC. GFS/NAM HAVING A HARD TIME PINPOINTING
WHICH DAY WOULD BE BEST FOR AN MCS TO ROLL THROUGH AND INSTEAD HAVE
SEVERAL WAVES OF PRECIP MOVING THROUGH MONDAY THROUGH WEDNESDAY. THIS
PROBABLY HAS LED TO SOME OF THE COOLER MAX TEMPS OFF THE MET. THE
BEST CHANCE FOR AN MCS TO APPROACH OUR REGION LOOKS TO BE LATER
TUESDAY AND TUESDAY NIGHT...AS CORFIDI VECTORS HAVE SUFFICIENT
MAGNITUDE AND DIRECTION TO LEAD SOMETHING TO SE WEST VA FROM THE NW.
ALTHOUGH IT MAY STILL OCCUR...WIDESPREAD STORMS AND HIGH QPF EARLY
TUESDAY LOOKS OVERDONE. NOT ENOUGH CONFIDENCE TO GO LIKELY BUT WILL
KEEP THE HIGHEST POPS IN THE TUESDAY PM AND TUESDAY NIGHT
TIME FRAME...WITH MORE PULSE TYPE STORMS ON MONDAY AND SMALLER POPS.
COLD FRONT DRAPED WEST TO EAST THROUGH THE GREAT LAKES ON TUESDAY
SINKS TO SE WEST VA AND NEAR NW NC INTO WEDNESDAY. THEREFORE THOSE
SPOTS HAVE THE BEST CHANCE OF STORMS CONTINUING INTO MIDWEEK.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 1222 PM EDT SATURDAY...
LOOKS LIKE WE WILL BE STUCK IN A HUMID SOMEWHAT STORMY BUT TYPICAL
LATE JULY PATTERN WITH THE RIDGE STAYING RIGHT ON THE SWRN DOORSTEP
OF OUR REGION...WITH THE BLACKSBURG FORECAST AREA REMAINING ON THE
SRN FRINGE OF THE TROUGH OVER THE NORTHEAST.
WILL BE GOING WITH DAILY THREAT OF SHRA/TSRA BUT WILL SEE ENHANCED
PROBABILITIES AS A SERIES OF SHORTWAVES GRAZE BY...BUT TIMING AT
THIS POINT IS UP IN THE AIR...WITH FRONTAL BOUNDARY SWINGING TOWARD
US IN THE WED-THU TIME FRAME THEN LIFTING NORTH AGAIN BY THE WEEKEND.
LOWS AT NIGHT WILL STAY IN THE 60S IN THE MTNS WITH LOWER 70S EAST
WITH HIGHS IN THE MID-UPPER 80S MTNS TO LOWER TO MID 90S EAST. OF
COURSE ANY CONVECTION AND OR BLOWOFF OF STORMS WILL LIMIT SOME
HEATING FROM TIME TO TIME DURING THE DAY.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
AS OF 145 AM EDT SUNDAY...
GRIDDED LAMP GUIDANCE BRINGS IFR CEILINGS INTO ROA/BLF AND BCB BY
09Z. EAST TO NORTHEAST DIRECTION OF THE SURFACE AND LOW LEVEL
WINDS WILL PRODUCE SOME FOG AND DRIZZLE...ESPECIALLY ON THE EAST
SLOPES OF THE BLUE RIDGE OVERNIGHT. LAMP GUIDANCE HAD CLOUDS
LIFTING TO MVFR AROUND 14-15Z BUT CONFIDENCE IS LOW THAT
IMPROVEMENT WILL BE THAT QUICK. THINK ALL LOCATIONS SHOULD
FINALLY REACH VFR CIGS BY MID AFTERNOON WITH LYH LIKELY BEING THE
LAST AIRPORT TO SCATTER OUT THE LOW CLOUDS.
ONCE CLOUDS BURN OFF...AN UPPER LEVEL TROUGH AND AFTERNOON
HEATING MAY GENERATE AN ISOLATED SHOWER OR THUNDERSTORM THIS
AFTERNOON BUT TOO ISOLATED TO INCLUDE MENTION IN THE TAFS.
FOG MAY REFORM ACROSS THE MOUNTAIN VALLEYS TONIGHT INTO MONDAY
MORNING.
NW FLOW ALOFT LOOKS TO PERSIST MONDAY THRU THURSDAY...RESULTING
IN BOUTS OF SHRA/TSRA THRU THE PERIOD. OTHERWISE EXPECTING VFR
OUTSIDE OF ANY PERIODS OF THUNDERSTORMS...AND CONTINUED LATE NIGHT
FOG THROUGH MID OR LATE WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KM
LONG TERM...WP
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
227 AM CDT SUN JUL 22 2012
.SHORT TERM...THROUGH TUESDAY
227 AM CDT SUN JUL 22 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS MORNING SHOWED A WEAK AREA OF LOW
PRESSURE OVER SOUTH DAKOTA WITH A WARM FRONT EXTENDING EAST ACROSS
SOUTHERN MINNESOTA INTO CENTRAL WISCONSIN. LOCAL AND REGIONAL
RADARS SHOWING A COMPLEX OF SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF THE BOUNDARY OVER SOUTHERN MINNESOTA.
WATER VAPOR IMAGERY LOOP SHOWS A WEAK SHORT WAVE TROUGH OVER
WESTERN MINNESOTA HELPED TO SPARK THE CONVECTION THIS MORNING. THE
22.03Z RAP BRINGS THIS SHORT WAVE TROUGH ACROSS THE AREA ON ITS
WAY TO THE SOUTHERN TIP OF LAKE MICHIGAN BY LATE MORNING. THE WAVE
IS PRODUCING AROUND 4 PVU/S OF VORTICITY ADVECTION IN THE 500-300
MB LAYER AND IS EXPECTED TO CONTINUE DOING SO AS IT MOVES
OVERHEAD. THE LOW LEVEL MOISTURE TRANSPORT INTO THE ACTIVITY IS
EXPECTED TO GRADUALLY TURN TO THE SOUTHWEST THE FARTHER EAST THE
ACTIVITY GETS...BUT SHOULD CONTINUE TO FEED INTO IT UNTIL AFTER
SUNRISE. WILL CONTINUE TO MONITOR RADAR TRENDS BUT THINKING THERE
SHOULD BE DECENT COVERAGE OF SHOWERS FOR AREAS WEST OF THE
MISSISSIPPI RIVER FOR THE FIRST HALF OF THE MORNING. COVERAGE
SHOULD THEN START TO DIMINISH AS THE MOISTURE FEED STARTS TO
WEAKEN WITH ONLY SOME WIDELY SCATTERED ACTIVITY LEFT OVER FOR THE
AFTERNOON.
ONCE THE FRONT GOES THROUGH TODAY...IT WILL BECOME STATIONARY JUST
SOUTH OF THE AREA AND BECOME THE FOCUS FOR THE REMAINDER OF THE
PERIOD. THE 22.00Z NAM...AND TO A LESSER DEGREE...THE 21.12Z ECMWF
SHOW THE FRONTOGENESIS GRADUALLY INCREASING AND BECOMING DEEPER
ALONG THE FRONT STARTING MONDAY. BY LATE MONDAY NIGHT INTO TUESDAY
MORNING...THE FRONTOGENESIS IS EXPECTED TO BE MODERATE IN
STRENGTH IN THE 1000-850 MB LAYER AND WEAK IN THE 850-500 MB
LAYER. THE NEXT SURFACE LOW WILL BE TAKING SHAPE OVER NEBRASKA OR
SOUTH DAKOTA ALONG THE WESTERN PART OF THE FRONT. AS THIS
CONTINUES TO DEVELOP...THE LOW LEVEL WARM AIR ADVECTION OVER THE
FRONT WILL BE INCREASING WITH THE ECMWF SHOWING AROUND 2 UBAR/S
OF UP GLIDE ON THE 315K ISENTROPIC SURFACE OVER THE FRONT. THESE
HAVE BEEN CONSISTENT SIGNALS SO HAVE RAISED THE RAIN CHANCES UP TO
50 PERCENT FOR A GOOD SHARE OF THE AREA NORTH OF THE FRONT. THE
MOISTURE TRANSPORT INTO THE FRONT DOES NOT LOOK TO BE VERY STRONG
WITH BOTH THE NAM AND ECMWF SUGGESTING IT WILL BE MORE PARALLEL TO
THE FRONT INSTEAD OF INTO IT. THE FORCING THEN STARTS TO WEAKEN
BUT DOES NOT TOTALLY DISSIPATE TUESDAY AFTERNOON SO MAINTAINED A
30 PERCENT CHANCE FOR MUCH OF THE AREA.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
227 AM CDT SUN JUL 22 2012
BOTH THE 21.12Z AND 22.00Z RUNS OF THE ECMWF HAVE SUGGESTED A
PATTERN SHIFT WILL BE TAKING PLACE THROUGH THE EXTENDED. THE MEAN
UPPER LEVEL RIDGE IS EXPECTED TO GET FLATTENED AND PUSHED TO THE
SOUTHEAST AS AN UPPER LEVEL LOW MOVES ALONG THE CANADIAN BORDER.
AS THIS SYSTEM MOVES BY LATE IN THE PERIOD...THE RIDGE THEN DOES
NOT BUILD BACK OVER THE ROCKIES NEARLY AS STRONG AS ANOTHER STORM
SYSTEM LOOKS TO BE MOVING ONSHORE WITH MEAN TROUGHING DEVELOPING
ALONG THE WEST COAST KEEPING THE FLOW OVER THE UPPER MIDWEST MORE
OF A ZONAL TO WEAK NORTHWEST PATTERN. AS THE UPPER LEVEL LOW
APPROACHES...THE SURFACE LOW WILL TRACK EAST ALONG THE FRONTAL
BOUNDARY WITH INCREASING FRONTOGENESIS AND ISENTROPIC UP GLIDE.
THIS FORCING WILL COMBINE WITH THE LIFT AHEAD OF THE UPPER LEVEL
LOW AND PROVIDE GOOD FORCING FOR RAIN OVER THE AREA TUESDAY NIGHT
INTO WEDNESDAY NIGHT. THE RAIN CHANCES WILL CONTINUE THURSDAY INTO
FRIDAY BUT WILL BE ON THE DECREASE AS THE SYSTEM MOVES SLOWLY PAST
THE AREA.
&&
.AVIATION...TONIGHT AND SUNDAY
1141 PM CDT SAT JUL 21 2012
SUBTLE SHORT WAVE TROUGH GENERATING ENOUGH LIFT AND LOW LEVEL
RESPONSE TO SPARK CONVECTION OVER SOUTHWEST MINNESOTA LATE THIS
EVENING AS FORECAST. MESOSCALE MODELS TRACK THIS EAST-SOUTHEAST SO
EXPECT SOME IMPACT TO TAF SITES BUT SHOULD STILL REMAIN MAINLY VFR.
ADDED THREAT FOR -TSRA AT KRST AFTER 22/07Z BUT EXPECT CONVECTION TO
WEAKEN AS IT PROGRESSES EAST BY DAYBREAK.
AFTER THIS MORNING SHOWER ACTIVITY...HARD TO FIND ANY TYPE OF
FEATURE THAT WOULD GENERATE MORE LATER IN THE DAY SO EXCEPT FOR SOME
OCCASIONAL MID/HIGH LEVEL CLOUDS...VFR CONDITIONS TO PREVAIL INTO
SUNDAY NIGHT AND BROAD UPPER RIDGE CONTINUES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
227 AM CDT SUN JUL 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION.....SHEA
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1058 AM EDT SUN JUL 22 2012
.SYNOPSIS...
A WEAK TROUGH WILL MAKE ITS WAY INTO THE AREA THIS
AFTERNOON...BRINGING A CHANCE FOR SOME SHOWERS AND POSSIBLY A
THUNDERSTORM WITH IT...ESPECIALLY TO THE FINGER LAKES AND SOUTHERN
TIER REGIONS. A STRONGER TROUGH WILL MOVE THROUGH ON MONDAY
AFTERNOON...BRINGING YET ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE WILL BUILD BACK INTO THE AREA FOR THE
MIDDLE OF THE WEEK..
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE... THE VSBL SAT LOOP SHOWS AN EXPANDING AREA OF LWR
CLDS ATTM ACRS NE PA...INTO PTNS OF NY`S SRN TIER. WE DO EXPECT
THAT THIS CLD MASS...IN GENERAL...WILL EVOLVE INTO AN OPEN
CELLULAR CU FIELD BY EARLY AFTN. OTHWS...SUNNY SKIES WILL GIVE WAY
TO SCT-BKN MID-LVL CLDS AND SOME CU BY ARND 18Z...AS MOIST ADVECTS
IN FROM THE W. THE UPSHOT OF ALL THIS...IS THAT PTLY SUNNY SKIES
CAN BE ANTICIPATED AREA-WIDE THIS AFTN.
AS FAR AS CONVECTIVE POTENTIAL GOES...A WEAK MID-LVL TROUGH (SEEN
BEST ARND 700 MB) WILL BE DRIFTING ESEWD INTO WRN/CNTRL NY LTR
THIS AFTN INTO THE EVE...COUPLED WITH VERY WEAK LOW-LVL WAA. THIS
COMBO SHOULD HELP TRIGGER ISOLD-SCTD SHRA/TSRA...MAINLY ALG AND W
OF THE I-81 CORRIDOR. OVERALL...SVR POTENTIAL LOOKS LOW...AS MRNG
SNDGS SHOW SOME CINH IN THE 700-800 MB LYR AT BOTH ALY/BUF...WHICH
SHOULD SLOW PARCEL ACCELERATIONS A BIT (EVEN PROJECTED SB CAPE
VALUES ARE ONLY ARND 1000 J/KG ANYWAY). ALSO...DEEP-LYRD SHEAR IS
FAIRLY WEAK (20 KT OR SO IN THE LWST 6 KM).
BASED ON 925-850 MB TEMPS AT 12Z...AND ANTICIPATED WEAK THERMAL
ADVECTIONS...OUR FCST MAX TEMPS LOOK DECENT...AND ONLY VERY MINOR
CHGS WERE MADE.
PREV DISC... 630AM UPDATE...MODELS CONTINUE TO SHOW THE
FRONT/TROUGH FALLING APART AS IT REACHES THE CWA SOMETIME AFTER
MID DAY. THE HRRR IS A LITTLE FASTER, BUT APPEARS TO BE ALREADY
OVERDOING PRECIPITATION THIS MORNING. EVEN SO, IT SHOWS ONLY SOME
SHOWERS ALONG THE WESTERN CWA BORDER AND THEN BREAKING UP LATER
TODAY. DID DECIDE TO SPREAD POPS A LITTLE FURTHER EAST THIS
AFTERNOON, BUT REALLY DID NOT RAISE THEM ABOVE THE LOW END CHC
POPS THAT WERE ALREADY THERE. THERE IS JUST GREAT UNCERTAINTY WITH
THIS FORECAST, AS THERE IS UNCERTAINTY IN REGARDS TO THE STRENGTH
AND EXACT TIMING OF THE TROUGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE TROUGH, OR WHAT IS LEFT OF IT, SHOULD STALL IN THE VICINITY OF
THE CWA. THIS KEEPS A MENTION OF SHOWERS AND STORMS IN THE
FORECAST SUNDAY NIGHT. POPS INCREASE QUITE A BIT FOR MONDAY AS A
MORE VIGOROUS SHORT WAVE AND A PRE- FRONTAL TROUGH APPROACH THE
REGION. THE MAIN COLD FRONT WILL MOVE THROUGH MONDAY NIGHT, WHICH
WILL KEEP CONVECTION GOING THROUGH THE NIGHT AND INTO TUESDAY MORNING,
ALBEIT LOWER POPS WITH THE LOSS OF DAYTIME HEATING. HIGH PRESSURE
WILL QUICKLY TRY TO BUILD IN BEHIND THIS FRONT, BRINGING A HALT TO
SHOWERS BY LATE TUESDAY AFTERNOON OR EARLY TUESDAY EVENING.
HIGH TEMPERATURES WILL BE PERSISTENT FROM SUNDAY THROUGH TUESDAY,
REACHING INTO THE LOW TO MID 80S, TO POSSIBLY EVEN NEAR 90 TOWARDS
THE LAKE PLAIN. LOWS FOR MONDAY AND TUESDAY WILL ALSO BE
PERSISTENT, ON GETTING INTO THE MID 60S OVER MOST OF THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
UPPER PATTERN DURING THIS TIME FRAME WILL BE DOMINATED BY DEEP
CLOSED LOW PRESSURE ACROSS EASTERN CANADA...WITH A BUILDING RIDGE
ACROSS THE AMERICAN/CANADIAN WEST. FAIR AND DRY WX EXPECTED AT THE
START OF THE EXTENDED PERIOD AS HIGH PRESSURE DIVES SOUTH FROM
SOUTHERN CANADA. WITH WEAK NORTHERLY FLOW EXPECTED...TEMPS WILL
HOVER JUST BELOW NORMAL FOR DAYTIME HIGHS UNDER MOSTLY SUNNY
SKIES. HIGH PRESSURE WILL EXIT STAGE RIGHT WEDNESDAY NGT IN
ADVANCE OF A SLOW MOVING DISTURBANCE APPROACHING FROM THE WESTERN
AND CENTRAL GREAT LAKES. FCST MODELS IN RECENT DAYS HAVE BEEN
SUGGESTING A SLOW MOVING EASTWARD PROGRESSING SHORTWAVE/CLOSED LOW
EMANATING FROM BUILDING HEIGHTS OUT WEST...HOWEVER RECENT MODEL
RUNS HAVE STRUGGLED WITH TIMING AND LOCATION OF SEVERAL FEATURES
TO INCLUDE SFC LOW AND ASSOCIATED FRONTAL BOUNDARY POSITIONS. THAT
SAID...MODELS APPEAR TO BE CONVERGING ON A SOLUTION THAT BRINGS
THE FIRST SFC LOW EAST ACROSS OUR AREA ON THU...WITH CONTINUED
UNSETTLED CONDITIONS THEN EXPECTED THROUGH THE DURATION OF THE
FCST PERIOD AS ADDITIONAL SFC WAVES INTERACT WITH A STALLED FRONT
ACROSS THE NORTHERN MID-ATLANTIC AND OHIO VLY REGIONS.
AFOREMENTIONED CLOSED LOW WILL EVENTUALLY BEGIN UNDERCUTTING
EASTERN CANADIAN UPPER LOW BY LATE WEEK...HOWEVER WITH ANY POLAR
STREAM WINDS DISPLACED WELL TO THE NORTH...SHORTWAVE ENERGY/UPPER
LOW APPROACHING FROM THE NORTHWEST WILL INCH ALONG EVER SO SLOWLY. THE
END RESULT WILL BE CONTINUED CHANCES FOR RA/STORMS THROUGH THE
NEXT WEEKEND WITH AT OR BELOW NORMAL TEMPS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
UPSTREAM RADAR OBSERVATIONS INDICATING DEVELOPING CONVECTION THIS
HOUR JUST SOUTH OF TORONTO. FCST MODELS CONTINUE TO SUGGEST
SHWR/STORMS DEVELOPING FROM WEST TO EAST AS THE LATE
MORNING/AFTERNOON HRS PROGRESS AS A WEAK SURFACE TROUGH AND
SHORTWAVE MOVE OVER THE REGION. FOR NOW...OVERALL CONVECTIVE
CONVERGE REMAINS HIGHLY IN QUESTION AND BASED ON THIS...DO NOT
HAVE ENOUGH CONFIDENCE TO INCLUDE TSRA MENTION IN THE FCST. THAT
SAID...HAVE DECIDED TO INTRODUCE A TEMPO SHRA MENTION AT
ELM/BGM/ITH WHERE INSTABILITY WILL BE GREATEST. DAY SHIFT WILL HAVE
TO MONITOR TRENDS AND ADD OTHER TERMINALS IF DEEMED NECESSARY.
LGT SOUTHWEST WINDS EARLY ON WILL BECOME WESTERLY 5-10 KTS BY
MID/LATE AFTERNOON AS THE AFOREMENTIONED TROUGH PASSES. EXPECT
DEVELOPING CU BETWEEN 4-5 KFT LATER THIS MORNING AS DAYTIME
HEATING COMMENCES. BY TONIGHT...MODEL RH FIELDS SUGGEST INCREASING
AMOUNTS OF DRY AIR ALOFT WHICH WOULD LIKELY LEAD TO A GRADUAL
EROSION OF LINGERING LOW STRATUS FROM WEST TO EAST AND POTENTIAL
FOG DEVELOPMENT AT BOTH ITH AND ELM. FOG POSSIBILITIES WILL
INCREASE IF TERMINALS RECEIVE RAIN DURING THE DAY TODAY. FOR
NOW...HAVE MADE MVFR MENTION AT BOTH LOCATIONS.
OUTLOOK...
MON AND TUE...VFR...CHC MVFR IN SHWR/TSTM MAINLY IN THE AFTERNOON.
WED/THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...SLI
NEAR TERM...MLJ/SLI
SHORT TERM...SLI
LONG TERM...TAC
AVIATION...CMG
AREA FORECAST DISCUSSION...CORRECTED
NWS BINGHAMTON NY
655 AM EDT SUN JUL 22 2012
.SYNOPSIS...
A WEAK TROUGH WILL MAKE ITS WAY INTO THE AREA THIS
AFTERNOON...BRINGING A CHANCE FOR SOME SHOWERS AND POSSIBLY A
THUNDERSTORM WITH IT...ESPECIALLY TO THE FINGER LAKES AND SOUTHERN
TIER REGIONS. A STRONGER TROUGH WILL MOVE THROUGH ON MONDAY
AFTERNOON...BRINGING YET ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE WILL BUILD BACK INTO THE AREA FOR THE
MIDDLE OF THE WEEK..
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
630AM UPDATE...MODELS CONTINUE TO SHOW THE FRONT/TROUGH FALLING
APART AS IT REACHES THE CWA SOMETIME AFTER MID DAY. THE HRRR IS A
LITTLE FASTER, BUT APPEARS TO BE ALREADY OVERDOING PRECIPITATION
THIS MORNING. EVEN SO, IT SHOWS ONLY SOME SHOWERS ALONG THE
WESTERN CWA BORDER AND THEN BREAKING UP LATER TODAY. DID DECIDE TO
SPREAD POPS A LITTLE FURTHER EAST THIS AFTERNOON, BUT REALLY DID
NOT RAISE THEM ABOVE THE LOW END CHC POPS THAT WERE ALREADY THERE.
THERE IS JUST GREAT UNCERTAINTY WITH THIS FORECAST, AS THERE IS
UNCERTAINTY IN REGARDS TO THE STRENGTH AND EXACT TIMING OF THE
TROUGH.
PREVIOUS DISCUSSION...A COLD FRONT WILL APPROACH THE AREA AND
BEGIN TO DISSIPATE INTO MORE OF A WEAK TROUGH. IT MAY BE ENOUGH TO
TRIGGER SOME ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS OVER
THE CWA...WITH THE FINGER LAKES SEEING THE BEST CHANCE AT SEEING
CONVECTIVE DEVELOPMENT. CAPE VALUES OVER THE FINGER LAKES WILL BE
BETWEEN 1500 AND 2000 JOULES. LIS WILL BE AROUND -6. HOWEVER, THE
BEST CAPE WILL NOT OCCUR UNTIL LATE AFTERNOON INTO EARLY EVENING.
SO, IT MAY NOT BE ABLE TO CAPITALIZE ON DAYTIME HEATING. ALSO, MID
AND UPPER LEVEL LAPSE RATES ARE NOT IN FAVOR OF DEVELOPMENT. THE
MAIN LOW WILL BE PULLING WELL TO THE NORTH OF THE CWA, AS IT WILL
BE CENTERED NORTH OF THE HUDSON BAY. MODELS SHOW THE FRONT
CONTINUES TO DETERIORATE AS IT MOVES INTO THE CWA. BUT, STILL CAN
NOT RULE OUT SOME DEVELOPMENT LATER TODAY, SO AGAIN, CHC POPS IN
THE FINGER LAKE AND ISOLD IN THE REST OF THE AREA FOR NOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE TROUGH, OR WHAT IS LEFT OF IT, SHOULD STALL IN THE VICINITY OF
THE CWA. THIS KEEPS A MENTION OF SHOWERS AND STORMS IN THE
FORECAST SUNDAY NIGHT. POPS INCREASE QUITE A BIT FOR MONDAY AS A
MORE VIGOROUS SHORT WAVE AND A PRE- FRONTAL TROUGH APPROACH THE
REGION. THE MAIN COLD FRONT WILL MOVE THROUGH MONDAY NIGHT, WHICH
WILL KEEP CONVECTION GOING THROUGH THE NIGHT AND INTO TUESDAY MORNING,
ALBEIT LOWER POPS WITH THE LOSS OF DAYTIME HEATING. HIGH PRESSURE
WILL QUICKLY TRY TO BUILD IN BEHIND THIS FRONT, BRINGING A HALT TO
SHOWERS BY LATE TUESDAY AFTERNOON OR EARLY TUESDAY EVENING.
HIGH TEMPERATURES WILL BE PERSISTENT FROM SUNDAY THROUGH TUESDAY,
REACHING INTO THE LOW TO MID 80S, TO POSSIBLY EVEN NEAR 90 TOWARDS
THE LAKE PLAIN. LOWS FOR MONDAY AND TUESDAY WILL ALSO BE
PERSISTENT, ON GETTING INTO THE MID 60S OVER MOST OF THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
UPPER PATTERN DURING THIS TIME FRAME WILL BE DOMINATED BY DEEP
CLOSED LOW PRESSURE ACROSS EASTERN CANADA...WITH A BUILDING RIDGE
ACROSS THE AMERICAN/CANADIAN WEST. FAIR AND DRY WX EXPECTED AT THE
START OF THE EXTENDED PERIOD AS HIGH PRESSURE DIVES SOUTH FROM
SOUTHERN CANADA. WITH WEAK NORTHERLY FLOW EXPECTED...TEMPS WILL
HOVER JUST BELOW NORMAL FOR DAYTIME HIGHS UNDER MOSTLY SUNNY
SKIES. HIGH PRESSURE WILL EXIT STAGE RIGHT WEDNESDAY NGT IN
ADVANCE OF A SLOW MOVING DISTURBANCE APPROACHING FROM THE WESTERN
AND CENTRAL GREAT LAKES. FCST MODELS IN RECENT DAYS HAVE BEEN
SUGGESTING A SLOW MOVING EASTWARD PROGRESSING SHORTWAVE/CLOSED LOW
EMANATING FROM BUILDING HEIGHTS OUT WEST...HOWEVER RECENT MODEL
RUNS HAVE STRUGGLED WITH TIMING AND LOCATION OF SEVERAL FEATURES
TO INCLUDE SFC LOW AND ASSOCIATED FRONTAL BOUNDARY POSITIONS. THAT
SAID...MODELS APPEAR TO BE CONVERGING ON A SOLUTION THAT BRINGS
THE FIRST SFC LOW EAST ACROSS OUR AREA ON THU...WITH CONTINUED
UNSETTLED CONDITIONS THEN EXPECTED THROUGH THE DURATION OF THE
FCST PERIOD AS ADDITIONAL SFC WAVES INTERACT WITH A STALLED FRONT
ACROSS THE NORTHERN MID-ATLANTIC AND OHIO VLY REGIONS.
AFOREMENTIONED CLOSED LOW WILL EVENTUALLY BEGIN UNDERCUTTING
EASTERN CANADIAN UPPER LOW BY LATE WEEK...HOWEVER WITH ANY POLAR
STREAM WINDS DISPLACED WELL TO THE NORTH...SHORTWAVE ENERGY/UPPER
LOW APPROACHING FROM THE NORTHWEST WILL INCH ALONG EVER SO SLOWLY. THE
END RESULT WILL BE CONTINUED CHANCES FOR RA/STORMS THROUGH THE
NEXT WEEKEND WITH AT OR BELOW NORMAL TEMPS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
UPSTREAM RADAR OBSERVATIONS INDICATING DEVELOPING CONVECTION THIS
HOUR JUST SOUTH OF TORONTO. FCST MODELS CONTINUE TO SUGGEST
SHWR/STORMS DEVELOPING FROM WEST TO EAST AS THE LATE
MORNING/AFTERNOON HRS PROGRESS AS A WEAK SURFACE TROUGH AND
SHORTWAVE MOVE OVER THE REGION. FOR NOW...OVERALL CONVECTIVE
CONVERGE REMAINS HIGHLY IN QUESTION AND BASED ON THIS...DO NOT
HAVE ENOUGH CONFIDENCE TO INCLUDE TSRA MENTION IN THE FCST. THAT
SAID...HAVE DECIDED TO INTRODUCE A TEMPO SHRA MENTION AT
ELM/BGM/ITH WHERE INSTABILITY WILL BE GREATEST. DAYSHIFT WILL HAVE
TO MONITOR TRENDS AND ADD OTHER TERMINALS IF DEEMED NECESSARY.
LGT SOUTHWEST WINDS EARLY ON WILL BECOME WESTERLY 5-10 KTS BY
MID/LATE AFTERNOON AS THE AFOREMENTIONED TROUGH PASSES. EXPECT
DEVELOPING CU BETWEEN 4-5 KFT LATER THIS MORNING AS DAYTIME
HEATING COMMENCES. BY TONIGHT...MODEL RH FIELDS SUGGEST INCREASING
AMOUNTS OF DRY AIR ALOFT WHICH WOULD LIKELY LEAD TO A GRADUAL
EROSION OF LINGERING LOW STRATUS FROM WEST TO EAST AND POTENTIAL
FOG DEVELOPMENT AT BOTH ITH AND ELM. FOG POSSIBILITIES WILL
INCREASE IF TERMINALS RECEIVE RAIN DURING THE DAY TODAY. FOR
NOW...HAVE MADE MVFR MENTION AT BOTH LOCATIONS.
OUTLOOK...
MON AND TUE...VFR...CHC MVFR IN SHWR/TSTM MAINLY IN THE AFTERNOON.
WED/THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...SLI
NEAR TERM...SLI
SHORT TERM...SLI
LONG TERM...TAC
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
629 AM EDT SUN JUL 22 2012
.SYNOPSIS...
A WEAK TROUGH WILL MAKE ITS WAY INTO THE AREA THIS
AFTERNOON...BRINGING A CHANCE FOR SOME SHOWERS AND POSSIBLY A
THUNDERSTORM WITH IT...ESPECIALLY TO THE FINGER LAKES AND SOUTHERN
TIER REGIONS. A STRONGER TROUGH WILL MOVE THROUGH ON MONDAY
AFTERNOON...BRINGING YET ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE WILL BUILD BACK INTO THE AREA FOR THE
MIDDLE OF THE WEEK..
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
630AM UPDATE...MODELS CONTINUE TO SHOW THE FRONT/TROUGH FALLING
APART AS IT REACHES THE CWA SOMETIME AFTER MID DAY. THE HRRR IS A
LITTLE FASTER, BUT APPEARS TO BE ALREADY OVERDOING PRECIPITATION
THIS MORNING. EVEN SO, IT SHOWS ONLY SOME SHOWERS ALONG THE
WESTERN CWA BORDER AND THEN BREAKING UP LATER TODAY. DID DECIDE TO
SPREAD POPS A LITTLE FURTHER EAST THIS AFTERNOON, BUT REALLY DID
NOT RAISE THEM ABOVE THE LOW END CHC POPS THAT WERE ALREADY THERE.
THERE IS JUST GREAT UNCERTAINTY WITH THIS FORECAST, AS THERE IS
UNCERTAINTY IN REGARDS TO THE STRENGTH AND EXACT TIMING OF THE
TROUGH.
PREVIOUS DISCUSSION...A COLD FRONT WILL APPROACH THE AREA AND
BEGIN TO DISSIPATE INTO MORE OF A WEAK TROUGH. IT MAY BE ENOUGH TO
TRIGGER SOME ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS OVER
THE CWA...WITH THE FINGER LAKES SEEING THE BEST CHANCE AT SEEING
CONVECTIVE DEVELOPMENT. CAPE VALUES OVER THE FINGER LAKES WILL BE
BETWEEN 1500 AND 2000 JOULES. LIS WILL BE AROUND -6. HOWEVER, THE
BEST CAPE WILL NOT OCCUR UNTIL LATE AFTERNOON INTO EARLY EVENING.
SO, IT MAY NOT BE ABLE TO CAPITALIZE ON DAYTIME HEATING. ALSO, MID
AND UPPER LEVEL LAPSE RATES ARE NOT IN FAVOR OF DEVELOPMENT. THE
MAIN LOW WILL BE PULLING WELL TO THE NORTH OF THE CWA, AS IT WILL
BE CENTERED NORTH OF THE HUDSON BAY. MODELS SHOW THE FRONT
CONTINUES TO DETERIORATE AS IT MOVES INTO THE CWA. BUT, STILL CAN
NOT RULE OUT SOME DEVELOPMENT LATER TODAY, SO AGAIN, CHC POPS IN
THE FINGER LAKE AND ISOLD IN THE REST OF THE AREA FOR NOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE TROUGH, OR WHAT IS LEFT OF IT, SHOULD STALL IN THE VICINITY OF
THE CWA. THIS KEEPS A MENTION OF SHOWERS AND STORMS IN THE
FORECAST SUNDAY NIGHT. POPS INCREASE QUITE A BIT FOR MONDAY AS A
MORE VIGOROUS SHORT WAVE AND A PRE- FRONTAL TROUGH APPROACH THE
REGION. THE MAIN COLD FRONT WILL MOVE THROUGH MONDAY NIGHT, WHICH
WILL KEEP CONVECTION GOING THROUGH THE NIGHT AND INTO TUESDAY MORNING,
ALBEIT LOWER POPS WITH THE LOSS OF DAYTIME HEATING. HIGH PRESSURE
WILL QUICKLY TRY TO BUILD IN BEHIND THIS FRONT, BRINGING A HALT TO
SHOWERS BY LATE TUESDAY AFTERNOON OR EARLY TUESDAY EVENING.
HIGH TEMPERATURES WILL BE PERSISTENT FROM SUNDAY THROUGH TUESDAY,
REACHING INTO THE LOW TO MID 80S, TO POSSIBLY EVEN NEAR 90 TOWARDS
THE LAKE PLAIN. LOWS FOR MONDAY AND TUESDAY WILL ALSO BE
PERSISTENT, ON GETTING INTO THE MID 60S OVER MOST OF THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
UPPER PATTERN DURING THIS TIME FRAME WILL BE DOMINATED BY DEEP
CLOSED LOW PRESSURE ACROSS EASTERN CANADA...WITH A BUILDING RIDGE
ACROSS THE AMERICAN/CANADIAN WEST. FAIR AND DRY WX EXPECTED AT THE
START OF THE EXTENDED PERIOD AS HIGH PRESSURE DIVES SOUTH FROM
SOUTHERN CANADA. WITH WEAK NORTHERLY FLOW EXPECTED...TEMPS WILL
HOVER JUST BELOW NORMAL FOR DAYTIME HIGHS UNDER MOSTLY SUNNY
SKIES. HIGH PRESSURE WILL EXIT STAGE RIGHT WEDNESDAY NGT IN
ADVANCE OF A SLOW MOVING DISTURBANCE APPROACHING FROM THE WESTERN
AND CENTRAL GREAT LAKES. FCST MODELS IN RECENT DAYS HAVE BEEN
SUGGESTING A SLOW MOVING EASTWARD PROGRESSING SHORTWAVE/CLOSED LOW
EMANATING FROM BUILDING HEIGHTS OUT WEST...HOWEVER RECENT MODEL
RUNS HAVE STRUGGLED WITH TIMING AND LOCATION OF SEVERAL FEATURES
TO INCLUDE SFC LOW AND ASSOCIATED FRONTAL BOUNDARY POSITIONS. THAT
SAID...MODELS APPEAR TO BE CONVERGING ON A SOLUTION THAT BRINGS
THE FIRST SFC LOW EAST ACROSS OUR AREA ON THU...WITH CONTINUED
UNSETTLED CONDITIONS THEN EXPECTED THROUGH THE DURATION OF THE
FCST PERIOD AS ADDITIONAL SFC WAVES INTERACT WITH A STALLED FRONT
ACROSS THE NORTHERN MID-ATLANTIC AND OHIO VLY REGIONS.
AFOREMENTIONED CLOSED LOW WILL EVENTUALLY BEGIN UNDERCUTTING
EASTERN CANADIAN UPPER LOW BY LATE WEEK...HOWEVER WITH ANY POLAR
STREAM WINDS DISPLACED WELL TO THE NORTH...SHORTWAVE ENERGY/UPPER
LOW APPROACHING FROM THE NORTHWEST WILL INCH ALONG EVER SO SLOWLY. THE
END RESULT WILL BE CONTINUED CHANCES FOR RA/STORMS THROUGH THE
NEXT WEEKEND WITH AT OR BELOW NORMAL TEMPS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MID-LEVEL CLOUD DECK CURRENTLY MOVING OVER THE AREA IN ADVANCE OF
A WEAK SFC TROUGH OFF TO OUR WEST. UPSTREAM SFC OBS INDICATE
NEARLY STEADY TEMPS AS FAR WEST AS SOUTHERN ONTARIO AND EASTERN MI
THIS HR AS A RESULT OF INCREASING WARM AIR ADVECTION AHEAD OF
AFOREMENTIONED TROUGH. CONSIDERING CROSSOVER TEMPS WERE IN THE UPPER
50S YESTERDAY AFTERNOON IN ELM...AND WITH BEST MOISTURE POOLING SOUTH
ACROSS CENTRAL AND SOUTHERN PA THIS HR...HAVE BACKED OFF ON IFR
FOG MENTION AT THE ELM TERMINAL FOR NOW. FURTHER SOUTH AT
AVP...LATEST 11-3.9U SATELLITE IMAGERY SHOWING LEADING EDGE OF LOW
STRATUS SLOWLY WORKING NORTH THROUGH THE LWR WYOMING VLY. THAT
SAID...HAVE INSERTED A TEMPO MVFR MENTION AT 09Z TO ACCOUNT FOR
THE POSSIBILITY OF THESE CLOUDS MOVING OVER THE TERMINAL.
REMAINING SITES...EXPECT VFR THROUGH THE EARLY MORNING HRS.
AS WE PROGRESS THROUGH THE DAY TODAY...EXPECT LGT SW TO W WINDS
BETWEEN 5-10 KTS. PLENTY OF MID-LEVEL MOISTURE WILL REMAIN IN
PLACE THUS EXPECT A DEVELOPING STRATOCU ONCE AGAIN. FCST MODELS DO
HINT AT DEVELOPING SHWRS/STORMS BY EARLY AFTERNOON AS THETA-E
RIDGE MOVES INTO THE AREA...HOWEVER WITH VERY LITTLE UPPER-LEVEL
SUPPORT...NOT ENOUGH CONFIDENCE EXISTS FOR INCLUSION AT THIS
TIME.
OUTLOOK...
MON AND TUE...VFR...CHC MVFR IN SHWR/TSTM MAINLY IN THE AFTERNOON.
WED/THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...SLI
NEAR TERM...SLI
SHORT TERM...SLI
LONG TERM...TAC
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
630 AM CDT SUN JUL 22 2012
.AVIATION...
ELEVATED THUNDERSTORMS HAVE DEVELOPED THIS MORNING SOUTH OF THE
METROPLEX IN ASSOCIATION WITH A SUBTLE EASTERLY WAVE. ACTIVITY
EXTENDS SOUTHWARD BEYOND THE SOUTHERN CWA AND WILL LIKELY AFFECT
THE WACO TERMINAL PERIODICALLY OVER THE NEXT FEW HOURS. WILL
INCLUDE VCTS FOR KACT THROUGH 14Z...WITH THE THOUGHT THAT ACTIVITY
WILL SHIFT WEST AND WEAKEN AFTER SUNRISE. THE HRRR HAS DONE A GOOD
JOB SO FAR AND ALSO INDICATES WEAKENING AFTER 13Z. SO FAR STORMS
HAVE REMAINED SOUTH OF TARRANT AND DALLAS COUNTIES...AND WILL
LIKELY LEAVE OUT MENTION OF TS AT METROPLEX-AREA TERMINALS UNLESS
FUTURE TRENDS DEMAND OTHERWISE. IR LOOP DOES SHOW ACCAS SPREADING
ACROSS THE METROPLEX...SO MAY INCLUDE A VCSH FOR THE NEXT FEW
HOURS DUE TO THE POSSIBILITY OF A FEW ELEVATED SHOWERS DEVELOPING
IN THE AREA. ISOLATED STORMS MAY AGAIN BECOME POSSIBLE THIS
AFTERNOON BUT COVERAGE SHOULD REMAIN LOWER THAN THE PAST FEW DAYS.
AT THIS TIME...FEEL THE CHANCE WILL BE TOO LOW TO MENTION AT TAF
SITES. VFR CONDITIONS WITH SOUTH WINDS AROUND 10KT WILL CONTINUE
IN THE EVENING AND OVERNIGHT FORECASTS.
30
&&
.PREV DISCUSSION... /ISSUED 402 AM CDT SUN JUL 22 2012/
12Z UPPER AIR ANALYSIS INDICATED AN ELONGATED CYCLONIC SHEAR AXIS
AT THE H250 LEVEL EXTENDING FROM THE CAROLINAS WEST OVER THE
SOUTHEASTERN CONUS AND OVER THE RED RIVER IN THE SOUTHERN PLAINS.
ALTHOUGH SUBTLE...H700 STREAMLINES HINT AT A WEAK MID-LEVEL
DISTURBANCE OVER THE WESTERN GOMEX WITH LA AND TX COASTAL UPPER
AIR OBSERVATIONS HINT AT WEAK CYCLONIC CURVATURE. WATER VAPOR
IMAGERY DEPICTS THE ELONGATED SHEAR AXIS WELL AS A POCKET OF DRIER
AIR WITH A COUPLE OF EMBEDDED CYCLONIC EDDIES. ONE OF THESE EDDIES
WAS LOCATED OVER THE NORTHEASTERN PORTIONS OF THE CWA EARLY THIS
MORNING...AND WAS MOVING WEST-SOUTHWEST. REGIONAL RADARS INDICATED
ISOLATED THUNDERSTORM AND RAIN SHOWER ACTIVITY ALONG A LINE FROM
LUFKIN TOWARDS GOLDTHWAITE MOVING SOUTH AS OF 08Z.
TODAY AND TONIGHT...THE CYCLONIC CIRCULATION OVER THE NORTHEASTERN
CWA EARLY THIS MORNING IS ESSENTIALLY A WEAK SHORTWAVE TROUGH.
THIS FEATURE WILL CONTINUE TO MOVE WEST-SOUTHWEST THIS MORNING
PROVIDING SOME VERY WEAK LARGE SCALE FORCING FOR ASCENT OVER NORTH
TX. AS A RESULT WENT AHEAD AND KEPT A MENTION OF ISOLATED
THUNDERSTORMS IN ACROSS NORTH TX THIS MORNING AS SOME ELEVATED
THUNDERSTORM ACTIVITY CANNOT BE RULED OUT. ANY STORMS THAT DEVELOP
THIS MORNING ARE NOT EXPECTED TO BE STRONG OR SEVERE BUT COULD
PRODUCE CLOUD TO GROUND LIGHTNING. THIS TROUGH IS EXPECTED TO MOVE
WEST OF THE FORECAST AREA THIS AFTERNOON LEAVING WEAK FORCING FOR
SUBSIDENCE IN ITS WAKE. DESPITE WEAK SUBSIDENCE OVER THE AREA THIS
AFTERNOON...FORECAST SOUNDINGS FROM MOST GUIDANCE INDICATE AN
UNCAPPED ATMOSPHERE OVER NORTH AND CENTRAL TX. WITHOUT ANY
SIGNIFICANT FORCING TO FOCUS CONVECTION...WENT AHEAD AND LOWERED
POPS TO 10 PERCENT FOR ALL LOCATIONS AND ONLY MENTIONED ISOLATED
THUNDERSTORMS THROUGH THIS EVENING. ANY STORMS THAT DEVELOP ARE
EXPECTED TO BE PULSE TYPE STORMS PRIMARILY CAPABLE OF PRODUCING
MICROBURST WINDS. STORMS ARE NOT EXPECTED TO HOLD TOGETHER LONG
ENOUGH TO BE HAIL OR HEAVY RAIN PRODUCERS AT THIS TIME. EXPECT ANY
THUNDERSTORM ACTIVITY WILL DISSIPATE QUICKLY AROUND SUNSET.
AS THE SHORTWAVE MOVES WEST OF THE CWA...SURFACE LOW PRESSURE IS
EXPECTED TO FOLLOW SUIT WITH THE SURFACE LOW NEAR WICHITA FALLS
EARLY THIS MORNING EXPECTED TO MOVE TOWARDS GUTHRIE BY 21Z THIS
AFTERNOON. THIS IS IMPORTANT FOR NORTH AND CENTRAL TX BECAUSE
WHILE THE LOW REMAINS IN PLACE NEAR WICHITA FALLS...LOW LEVEL WIND
FIELDS MAINTAIN A WEST-SOUTHWESTERLY COMPONENT WHICH EQUATES TO
WEAK WARM AIR ADVECTION FOR AREAS GENERALLY ALONG AND WEST OF THE
INTERSTATE 35/35E CORRIDOR. CONSIDERING WE HAD ANOTHER DAY OF
RECORD HEAT YESTERDAY...WEAK WARM AIR ADVECTION WOULD NOT BRING
MUCH RELIEF FROM THE HEAT. ASSUMING THE SURFACE LOW MOVES WEST AS
EXPECTED BY THIS AFTERNOON...THIS SHOULD ALLOW LOW LEVEL WIND
FIELDS TO BACK AROUND TOWARDS THE SOUTH-SOUTHEAST WHICH WILL
RESULT IN COLD AIR ADVECTION AND COOLER TEMPERATURES FOR MUCH OF
NORTH AND CENTRAL TX. BECAUSE THIS TRANSITION TO COLD AIR
ADVECTION IS NOT EXPECTED UNTIL LATER IN THE DAY...HIGHS WILL
LIKELY TOP OUT ABOVE THE CENTURY MARK FOR THE WESTERN HALF OF THE
CWA ONCE AGAIN TODAY.
LOW LEVEL THICKNESS VALUES CONTINUE TO BE GREATER ALONG AND NORTH
OF INTERSTATE 20 TODAY...SO EXPECT THE WARMEST TEMPERATURES TO
OCCUR OVER THE NORTHWESTERN CWA WHERE HIGHS MAY ONCE AGAIN PEAK OUT
NEAR 105 DEGREES EARLY THIS AFTERNOON. SPC MESOANALYSIS INDICATES
THAT THE EASTERN HALF OF THE FORECAST AREA REMAINS VERY MOIST
DESPITE YESTERDAYS THUNDERSTORM ACTIVITY. MESOANALYSIS INDICATES
PWAT VALUES OF 1.8 INCHES EAST OF THE INTERSTATE 35 CORRIDOR AS OF
08Z. WHEN FACTORING IN HIGHER AFTERNOON RH VALUES WITH TODAYS
FORECAST HIGHS...HEAT INDEX VALUES ARE ONCE AGAIN EXPECTED TO TOP
OUT ABOVE THE 105 DEGREE MARK FOR THE NORTHERN HALF OF THE
FORECAST AREA. WILL MAINTAIN THE HEAT ADVISORY FOR THESE LOCATIONS
THROUGH THIS AFTERNOON AS A RESULT. SOUTHEASTERLY FLOW IS EXPECTED
TO PERSIST INTO EARLY NEXT WEEK WHICH WILL KEEP WEAK COLD AIR
ADVECTION IN PLACE AND SHOULD PREVENT ANY EXTENSION OF THE HEAT
ADVISORY INTO MONDAY.
MONDAY...SUNDAY NIGHT AND INTO MONDAY MODELS CONSISTENTLY BRING
THE WEAK MID-LEVEL CYCLONIC FEATURE OVER THE WESTERN GOMEX WEST
OVER SOUTH TX. EARLY MORNING WATER VAPOR IMAGERY DOES NOT SEEM TO
HAVE THIS FEATURE RESOLVED...SO THE ASSUMPTION IS THAT THIS SYSTEM
IS STRONGEST AT THE MID-LEVELS AND POSSIBLY REPRESENTS THE
REMNANTS OF OLD THUNDERSTORM ACTIVITY. EITHER WAY THIS FEATURE
LOOKS TO REMAIN JUST SOUTH OF THE FORECAST AREA AND SHOULD NOT
HAVE ANY DIRECT IMPACT ON PRECIPITATION CHANCES DURING THE DAY ON
MONDAY. AS THIS FEATURE MOVES WEST...IT WILL ALLOW SOUTHEASTERLY
FLOW TO DEEPEN OVER NORTH AND CENTRAL TX AND MODELS RESPOND BY
BRINGING PWATS UP TO NEARLY 2 INCHES ACROSS THE EASTERN TWO-THIRDS
OF THE CWA BY MONDAY AFTERNOON. THE GFS INDICATES THAT A PIECE OF
ENERGY FROM THE UPPER LEVEL SHEAR AXIS WILL MOVE WEST TOWARDS THE
FORECAST AREA SUNDAY NIGHT AS THE SHEAR AXIS LOSES IDENTITY AND IS
REPLACED BY UPPER LEVEL RIDGING FOR EARLY NEXT WEEK. WITH TROPICAL
MOISTURE IN PLACE...THIS FEATURE IS EXPECTED TO ACT LIKE A TUTT
LOW AND SPREAD LARGE SCALE FORCING FOR ASCENT OVER NORTH TX AS IT
MOVES OVERHEAD MONDAY AFTERNOON. AS A RESULT WENT AHEAD AND SPREAD
THE COVERAGE OF 20 POPS TO COVER MOST AREAS ALONG AND SOUTH OF
INTERSTATE 30 AND ALONG AND EAST OF INTERSTATE 35.
IF THIS FEATURE IS REAL...POPS MAY NEED TO BE INCREASED BEFORE
MONDAY AFTERNOON AS THUNDERSTORM COVERAGE MAY BE MORE SCATTERED IN
NATURE. AT THIS TIME IT IS DIFFICULT TO PICK OUT WHICH PORTION OF
THE UPPER SHEAR AXIS IS GOING TO ORGANIZE AND MOVE WEST...SO DID
NOT HAVE THE CONFIDENCE TO GO WITH HIGHER PERCENTAGES AT THIS
TIME. IF IT PANS OUT AS THE GFS FORECASTS...LOCALLY HEAVY RAINFALL
WOULD BE POSSIBLE AS TALL-SKINNY CAPE PROFILES IN A RELATIVELY
WEAKLY SHEARED ENVIRONMENT WOULD BE EXPECTED TO BE EFFICIENT
RAINFALL PRODUCERS. WET MICROBURSTS COULD NOT BE RULED OUT...BUT
OVERALL THE ENVIRONMENT WOULD NOT SUPPORT A GOOD MICROBURST/WIND
DAMAGE THREAT.
REMAINDER OF THE FORECAST...UPPER LEVEL RIDGING IS EXPECTED TO
BUILD OVER THE WESTERN GULF WHILE THE SOUTH TX MID-LEVEL LOW MOVES
TOWARDS NEW MEXICO AND MERGES WITH OUR WESTWARD MOVING SHORTWAVE
TROUGH INTO ONE LARGE UPPER LEVEL WEAKNESS OVER THE SOUTHERN HIGH
PLAINS. IN GENERAL EXPECT WEAK UPPER RIDGING TO DOMINATE NORTH AND
CENTRAL TX...SO MAINTAINED A DRY FORECAST FOR THE REMAINDER OF THE
WEEK. PERSISTENT WEAK SUBSIDENCE WILL SLOWLY WORK AWAY AT THE
HIGH PWAT AIR OVER THE FORECAST AREA DIMINISHING THE POTENTIAL FOR
PEAK HEATING ISOLATED STORMS LATER IN THE WEEK. BECAUSE DEEP
MOISTURE WILL REMAIN IN PLACE ON TUESDAY...CANNOT RULE OUT SOME
ISOLATED STORMS DURING THE PEAK HEATING HOURS OF THE DAY...BUT DID
NOT INCLUDE ANYTHING IN THE WORDED FORECAST AS THERE IS NO
DISCERNABLE FORCING FOR ASCENT AT THIS TIME. TEMPERATURES SHOULD
REMAIN JUST ABOVE NORMAL WITH HIGHS TOPPING OUT IN THE UPPER 90S
DAILY.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 101 78 97 76 97 / 10 10 20 10 5
WACO, TX 100 76 96 76 97 / 10 10 20 10 5
PARIS, TX 98 74 95 73 96 / 10 10 10 10 5
DENTON, TX 101 77 98 76 97 / 10 10 10 10 5
MCKINNEY, TX 99 76 97 75 96 / 10 10 20 10 5
DALLAS, TX 101 79 97 76 97 / 10 10 20 10 5
TERRELL, TX 99 76 95 74 96 / 10 10 20 10 5
CORSICANA, TX 98 77 94 74 95 / 10 10 20 10 5
TEMPLE, TX 100 74 96 73 96 / 10 10 20 10 5
MINERAL WELLS, TX 102 74 99 73 98 / 10 10 10 10 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR TXZ091>095-100>107-
115>123.
&&
$$
30/69
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
945 AM EDT SUN JUL 22 2012
.SYNOPSIS...
A FRONTAL BOUNDARY FROM NORTH CAROLINA INTO TENNESSEE WILL
DISSIPATE TODAY. HIGH PRESSURE WILL STRETCH FROM THE CENTRAL
PLAINS TO THE SOUTHEAST COAST FROM TONIGHT INTO MONDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTH BY WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT SUNDAY...
CLOUDY SKIES WILL LINGER THROUGH MUCH OF THE MORNING...THEN SCOUR
DURING THE AFTERNOON. A FEW SHOWERS TRACKING ACROSS THE NORTH
CAROLINA AND GRAYSON HIGHLANDS THIS MORNING. THESE SHOWERS SHOULD
FADE SOME IN AREAL COVERAGE MOVING EAST...THEN REMNANTS/OUTFLOW
BOUNDARIES WILL GENERATE MORE SHOWERS AND THUNDERSTORMS THIS
AFTERNOON. MAJORITY OF THE MODELS HAVE GENEROUS POPS ACROSS RNK
SOUTHERN TIER COUNTIES THIS AFTERNOON. THEREFORE WILL MAINTAIN SOME
SHOWERS IN THE AFTERNOON WHILE KEEPING THE NORTH DRY.
AS OF 415 AM EDT SUNDAY...
RADAR SHOWED ISOLATED SHOWERS FROM SMYTH AND GRAYSON COUNTIES
INTO THE NORTHWEST NORTH CAROLINA MOUNTAINS. THEY REST OF THE
PRECIPITATION FROM EARLIER TONIGHT HAS EITHER DISSIPATED OR MOVED
SOUTHEAST OUT OF THE FORECAST AREA. VAD WIND PROFILES FROM AREA
RADARS SHOWED A NORTH TO NORTHEAST WIND IN THE LOWER 1-4KFT WITH
WEST WINDS ABOVE THIS LAYER. FRONT EXTENDING ACROSS NORTH CAROLINA
AND TENNESSEE WILL CONTINUE TO WEAKEN AND DISSIPATE TODAY WITH THE
WEDGE ERODING AND SURFACE WINDS BECOMING SOUTH TO SOUTHWEST OVER
THE FORECAST AREA BY MID AFTERNOON.
EXPECT LOW CLOUDS TO HOLD IN EAST OF THE BLUE RIDGE THIS MORNING.
EVEN IF COUNTIES IN THE NORTHEAST PART OF THE FORECAST AREA DO NOT
SCATTER OUT UNTIL LATER TODAY...EVEN JUST A COUPLE HOURS OF SUN
WILL BRING TEMPERATURES WELL INTO THE 80S. USED A NON DIURNAL
HOURLY TEMPERATURE FORECAST BASED ON THE GRIDDED LAMP GUIDANCE AND
EXPECTED CLOUD COVER.
FR PROBABILITY OF PRECIPITATION...MODELS HELD ON TO A LOW CHANCE
THIS MORNING. HRRR AND LOCAL WRF SHOWED SHOWERS AND THUNDERSTORMS
DEVELOPING THIS AFTERNOON SOUTH OF HWY 460. ADJUSTED TIMING AND
COVERAGE OF THE PRECIPITATION IN THE SOUTH THIS AFTERNOON.
ONCE STORMS DISSIPATE IN THE EVENING...LITTLE TO NO PRECIPITATION
EXPECTED OVERNIGHT. MAV GUIDANCE LOOKED REASONABLE FOR MINIMUM
TEMPERATURES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SUNDAY...
HEIGHTS INCREASE INTO EARLY NEXT WEEK AS A SLICE OF THE UPPER RIDGE
RESPONSIBLE FOR THE HOT WEATHER ACROSS THE HEARTLAND STRETCHES
EASTWARD. H85 TEMPS WILL RISE TO AROUND +20C. CONSIDERING THE
MOVEMENT OF THE UPPER RIDGE AND ITS POSITION BY TUESDAY ...MOVING
JUST TO OUR SW WHICH WILL DELIVER A DOWNSLOPING NW COMPONENT...TEMPS
MAY VERIFY THE WARMEST GUIDANCE VALUES. MOS HAS BEEN TOO COOL WITH
TEMPS ACROSS THE MIDWEST...AND THIS MAY CONTINUE INTO THE OHIO
VALLEY AND MIDDLE ATLANTIC. GFS/NAM HAVING A HARD TIME PINPOINTING
WHICH DAY WOULD BE BEST FOR AN MCS TO ROLL THROUGH AND INSTEAD HAVE
SEVERAL WAVES OF PRECIP MOVING THROUGH MONDAY THROUGH WEDNESDAY. THIS
PROBABLY HAS LED TO SOME OF THE COOLER MAX TEMPS OFF THE MET. THE
BEST CHANCE FOR AN MCS TO APPROACH OUR REGION LOOKS TO BE LATER
TUESDAY AND TUESDAY NIGHT...AS CORFIDI VECTORS HAVE SUFFICIENT
MAGNITUDE AND DIRECTION TO LEAD SOMETHING TO SE WEST VA FROM THE NW.
ALTHOUGH IT MAY STILL OCCUR...WIDESPREAD STORMS AND HIGH QPF EARLY
TUESDAY LOOKS OVERDONE. NOT ENOUGH CONFIDENCE TO GO LIKELY BUT WILL
KEEP THE HIGHEST POPS IN THE TUESDAY PM AND TUESDAY NIGHT
TIME FRAME...WITH MORE PULSE TYPE STORMS ON MONDAY AND SMALLER POPS.
COLD FRONT DRAPED WEST TO EAST THROUGH THE GREAT LAKES ON TUESDAY
SINKS TO SE WEST VA AND NEAR NW NC INTO WEDNESDAY. THEREFORE THOSE
SPOTS HAVE THE BEST CHANCE OF STORMS CONTINUING INTO MIDWEEK.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 1222 PM EDT SATURDAY...
LOOKS LIKE WE WILL BE STUCK IN A HUMID SOMEWHAT STORMY BUT TYPICAL
LATE JULY PATTERN WITH THE RIDGE STAYING RIGHT ON THE SWRN DOORSTEP
OF OUR REGION...WITH THE BLACKSBURG FORECAST AREA REMAINING ON THE
SRN FRINGE OF THE TROUGH OVER THE NORTHEAST.
WILL BE GOING WITH DAILY THREAT OF SHRA/TSRA BUT WILL SEE ENHANCED
PROBABILITIES AS A SERIES OF SHORTWAVES GRAZE BY...BUT TIMING AT
THIS POINT IS UP IN THE AIR...WITH FRONTAL BOUNDARY SWINGING TOWARD
US IN THE WED-THU TIME FRAME THEN LIFTING NORTH AGAIN BY THE WEEKEND.
LOWS AT NIGHT WILL STAY IN THE 60S IN THE MTNS WITH LOWER 70S EAST
WITH HIGHS IN THE MID-UPPER 80S MTNS TO LOWER TO MID 90S EAST. OF
COURSE ANY CONVECTION AND OR BLOWOFF OF STORMS WILL LIMIT SOME
HEATING FROM TIME TO TIME DURING THE DAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
AS OF 145 AM EDT SUNDAY...
GRIDDED LAMP GUIDANCE HAD CLOUDS LIFTING TO MVFR AROUND 16Z AT
ROA/LYH/DAN AND BCB BUT CONFIDENCE IS LOW THAT IMPROVEMENT WILL BE
THAT QUICK. THINK ALL LOCATIONS SHOULD FINALLY REACH VFR CIGS BY
MID AFTERNOON WITH LYH LIKELY BEING THE LAST AIRPORT TO SCATTER
OUT THE LOW CLOUDS.
ONCE CLOUDS BURN OFF...AN UPPER LEVEL TROUGH AND AFTERNOON
HEATING MAY GENERATE AN ISOLATED SHOWER OR THUNDERSTORM THIS
AFTERNOON BUT TOO ISOLATED TO INCLUDE MENTION IN THE TAFS.
FOG MAY REFORM ACROSS THE MOUNTAIN VALLEYS TONIGHT INTO MONDAY
MORNING. HAVE ADDED LIFR FOG IN THE GREENBRIER VALLEY FOR THE LWB
AIRPORT.
NW FLOW ALOFT LOOKS TO PERSIST MONDAY THRU THURSDAY...RESULTING
IN BOUTS OF SHRA/TSRA THRU THE PERIOD. OTHERWISE EXPECTING VFR
OUTSIDE OF ANY PERIODS OF THUNDERSTORMS...AND CONTINUED LATE NIGHT
FOG THROUGH MID OR LATE WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/RCS
SHORT TERM...KM
LONG TERM...WP
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
725 AM EDT SUN JUL 22 2012
.SYNOPSIS...
A FRONTAL BOUNDARY FROM NORTH CAROLINA INTO TENNESSEE WILL
DISSIPATE TODAY. HIGH PRESSURE WILL STRETCH FROM THE CENTRAL
PLAINS TO THE SOUTHEAST COAST FROM TONIGHT INTO MONDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTH BY WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT SUNDAY...
RADAR SHOWED ISOLATED SHOWERS FROM SMYTH AND GRAYSON COUNTIES INTO
THE NORTHWEST NORTH CAROLINA MOUNTAINS. THEY REST OF THE
PRECIPITATION FROM EARLIER TONIGHT HAS EITHER DISSIPATED OR MOVD
SOUTHEAST OUT OF THE FORECAST AREA. VAD WIND PROFILES FROM AREA
RADARS SHOWED A NORTH TO NORTHEAST WIND IN THE LOWER 1-4KFT WITH
WEST WINDS ABOVE THIS LAYER. FRONT EXTENDING ACROSS NORTH CAROLINA
AND TENNESSEE WILL CONTINUE TO WEAKEN AND DISSIPATE TODAY WITH
THE WEDGE ERODING AND SURFACE WINDS BECOMING SOUTH TO SOUTHWEST
OVER THE FORECAST AREA BY MID AFTERNOON.
EXPECT LOW CLOUDS TO HOLD IN EAST OF THE BLUE RIDGE THIS MORNING.
EVEN IF COUNTIES IN THE NORTHEAST PART OF THE FORECAST AREA DO NOT
SCATTER OUT UNTIL LATER TODAY...EVEN JUST A COUPLE HOURS OF SUN
WILL BRING TEMPERATURES WELL INTO THE 80S. USED A NON DIURNAL
HOURLY TEMPERATURE FORECAST BASED ON THE GRIDDED LAMP GUIDANCE AND
EXPECTED CLOUD COVER.
FR PROBABILITY OF PRECIPITATION...MODELS HELD ON TO A LOW CHANCE
THIS MORNING. HRRR AND LOCAL WRF SHOWED SHOWERS AND THUNDERSTORMS
DEVELOPING THIS AFTERNOON SOUTH OF HWY 460. ADJUSTED TIMING AND
COVERAGE OF THE PRECIPITATION IN THE SOUTH THIS AFTERNOON.
ONCE STORMS DISSIPATE IN THE EVENING...LITTLE TO NO PRECIPITATION
EXPECTED OVERNIGHT. MAV GUIDANCE LOOKED REASONABLE FOR MINIMUM
TEMPERATURES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SUNDAY...
HEIGHTS INCREASE INTO EARLY NEXT WEEK AS A SLICE OF THE UPPER RIDGE
RESPONSIBLE FOR THE HOT WEATHER ACROSS THE HEARTLAND STRETCHES
EASTWARD. H85 TEMPS WILL RISE TO AROUND +20C. CONSIDERING THE
MOVEMENT OF THE UPPER RIDGE AND ITS POSITION BY TUESDAY ...MOVING
JUST TO OUR SW WHICH WILL DELIVER A DOWNSLOPING NW COMPONENT...TEMPS
MAY VERIFY THE WARMEST GUIDANCE VALUES. MOS HAS BEEN TOO COOL WITH
TEMPS ACROSS THE MIDWEST...AND THIS MAY CONTINUE INTO THE OHIO
VALLEY AND MIDDLE ATLANTIC. GFS/NAM HAVING A HARD TIME PINPOINTING
WHICH DAY WOULD BE BEST FOR AN MCS TO ROLL THROUGH AND INSTEAD HAVE
SEVERAL WAVES OF PRECIP MOVING THROUGH MONDAY THROUGH WEDNESDAY. THIS
PROBABLY HAS LED TO SOME OF THE COOLER MAX TEMPS OFF THE MET. THE
BEST CHANCE FOR AN MCS TO APPROACH OUR REGION LOOKS TO BE LATER
TUESDAY AND TUESDAY NIGHT...AS CORFIDI VECTORS HAVE SUFFICIENT
MAGNITUDE AND DIRECTION TO LEAD SOMETHING TO SE WEST VA FROM THE NW.
ALTHOUGH IT MAY STILL OCCUR...WIDESPREAD STORMS AND HIGH QPF EARLY
TUESDAY LOOKS OVERDONE. NOT ENOUGH CONFIDENCE TO GO LIKELY BUT WILL
KEEP THE HIGHEST POPS IN THE TUESDAY PM AND TUESDAY NIGHT
TIME FRAME...WITH MORE PULSE TYPE STORMS ON MONDAY AND SMALLER POPS.
COLD FRONT DRAPED WEST TO EAST THROUGH THE GREAT LAKES ON TUESDAY
SINKS TO SE WEST VA AND NEAR NW NC INTO WEDNESDAY. THEREFORE THOSE
SPOTS HAVE THE BEST CHANCE OF STORMS CONTINUING INTO MIDWEEK.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 1222 PM EDT SATURDAY...
LOOKS LIKE WE WILL BE STUCK IN A HUMID SOMEWHAT STORMY BUT TYPICAL
LATE JULY PATTERN WITH THE RIDGE STAYING RIGHT ON THE SWRN DOORSTEP
OF OUR REGION...WITH THE BLACKSBURG FORECAST AREA REMAINING ON THE
SRN FRINGE OF THE TROUGH OVER THE NORTHEAST.
WILL BE GOING WITH DAILY THREAT OF SHRA/TSRA BUT WILL SEE ENHANCED
PROBABILITIES AS A SERIES OF SHORTWAVES GRAZE BY...BUT TIMING AT
THIS POINT IS UP IN THE AIR...WITH FRONTAL BOUNDARY SWINGING TOWARD
US IN THE WED-THU TIME FRAME THEN LIFTING NORTH AGAIN BY THE WEEKEND.
LOWS AT NIGHT WILL STAY IN THE 60S IN THE MTNS WITH LOWER 70S EAST
WITH HIGHS IN THE MID-UPPER 80S MTNS TO LOWER TO MID 90S EAST. OF
COURSE ANY CONVECTION AND OR BLOWOFF OF STORMS WILL LIMIT SOME
HEATING FROM TIME TO TIME DURING THE DAY.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 145 AM EDT SUNDAY...
GRIDDED LAMP GUIDANCE HAD CLOUDS LIFTING TO MVFR AROUND 16Z AT
ROA/LYH/DAN AND BCB BUT CONFIDENCE IS LOW THAT IMPROVEMENT WILL BE
THAT QUICK. THINK ALL LOCATIONS SHOULD FINALLY REACH VFR CIGS BY
MID AFTERNOON WITH LYH LIKELY BEING THE LAST AIRPORT TO SCATTER
OUT THE LOW CLOUDS.
ONCE CLOUDS BURN OFF...AN UPPER LEVEL TROUGH AND AFTERNOON
HEATING MAY GENERATE AN ISOLATED SHOWER OR THUNDERSTORM THIS
AFTERNOON BUT TOO ISOLATED TO INCLUDE MENTION IN THE TAFS.
FOG MAY REFORM ACROSS THE MOUNTAIN VALLEYS TONIGHT INTO MONDAY
MORNING. HAVE ADDED LIFR FOG IN THE GREENBRIER VALLEY FOR THE LWB
AIRPORT.
NW FLOW ALOFT LOOKS TO PERSIST MONDAY THRU THURSDAY...RESULTING
IN BOUTS OF SHRA/TSRA THRU THE PERIOD. OTHERWISE EXPECTING VFR
OUTSIDE OF ANY PERIODS OF THUNDERSTORMS...AND CONTINUED LATE NIGHT
FOG THROUGH MID OR LATE WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KM
LONG TERM...WP
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
556 AM CDT SUN JUL 22 2012
.SHORT TERM...THROUGH TUESDAY
227 AM CDT SUN JUL 22 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS MORNING SHOWED A WEAK AREA OF LOW
PRESSURE OVER SOUTH DAKOTA WITH A WARM FRONT EXTENDING EAST ACROSS
SOUTHERN MINNESOTA INTO CENTRAL WISCONSIN. LOCAL AND REGIONAL
RADARS SHOWING A COMPLEX OF SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF THE BOUNDARY OVER SOUTHERN MINNESOTA.
WATER VAPOR IMAGERY LOOP SHOWS A WEAK SHORT WAVE TROUGH OVER
WESTERN MINNESOTA HELPED TO SPARK THE CONVECTION THIS MORNING. THE
22.03Z RAP BRINGS THIS SHORT WAVE TROUGH ACROSS THE AREA ON ITS
WAY TO THE SOUTHERN TIP OF LAKE MICHIGAN BY LATE MORNING. THE WAVE
IS PRODUCING AROUND 4 PVU/S OF VORTICITY ADVECTION IN THE 500-300
MB LAYER AND IS EXPECTED TO CONTINUE DOING SO AS IT MOVES
OVERHEAD. THE LOW LEVEL MOISTURE TRANSPORT INTO THE ACTIVITY IS
EXPECTED TO GRADUALLY TURN TO THE SOUTHWEST THE FARTHER EAST THE
ACTIVITY GETS...BUT SHOULD CONTINUE TO FEED INTO IT UNTIL AFTER
SUNRISE. WILL CONTINUE TO MONITOR RADAR TRENDS BUT THINKING THERE
SHOULD BE DECENT COVERAGE OF SHOWERS FOR AREAS WEST OF THE
MISSISSIPPI RIVER FOR THE FIRST HALF OF THE MORNING. COVERAGE
SHOULD THEN START TO DIMINISH AS THE MOISTURE FEED STARTS TO
WEAKEN WITH ONLY SOME WIDELY SCATTERED ACTIVITY LEFT OVER FOR THE
AFTERNOON.
ONCE THE FRONT GOES THROUGH TODAY...IT WILL BECOME STATIONARY JUST
SOUTH OF THE AREA AND BECOME THE FOCUS FOR THE REMAINDER OF THE
PERIOD. THE 22.00Z NAM...AND TO A LESSER DEGREE...THE 21.12Z ECMWF
SHOW THE FRONTOGENESIS GRADUALLY INCREASING AND BECOMING DEEPER
ALONG THE FRONT STARTING MONDAY. BY LATE MONDAY NIGHT INTO TUESDAY
MORNING...THE FRONTOGENESIS IS EXPECTED TO BE MODERATE IN
STRENGTH IN THE 1000-850 MB LAYER AND WEAK IN THE 850-500 MB
LAYER. THE NEXT SURFACE LOW WILL BE TAKING SHAPE OVER NEBRASKA OR
SOUTH DAKOTA ALONG THE WESTERN PART OF THE FRONT. AS THIS
CONTINUES TO DEVELOP...THE LOW LEVEL WARM AIR ADVECTION OVER THE
FRONT WILL BE INCREASING WITH THE ECMWF SHOWING AROUND 2 UBAR/S
OF UP GLIDE ON THE 315K ISENTROPIC SURFACE OVER THE FRONT. THESE
HAVE BEEN CONSISTENT SIGNALS SO HAVE RAISED THE RAIN CHANCES UP TO
50 PERCENT FOR A GOOD SHARE OF THE AREA NORTH OF THE FRONT. THE
MOISTURE TRANSPORT INTO THE FRONT DOES NOT LOOK TO BE VERY STRONG
WITH BOTH THE NAM AND ECMWF SUGGESTING IT WILL BE MORE PARALLEL TO
THE FRONT INSTEAD OF INTO IT. THE FORCING THEN STARTS TO WEAKEN
BUT DOES NOT TOTALLY DISSIPATE TUESDAY AFTERNOON SO MAINTAINED A
30 PERCENT CHANCE FOR MUCH OF THE AREA.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
227 AM CDT SUN JUL 22 2012
BOTH THE 21.12Z AND 22.00Z RUNS OF THE ECMWF HAVE SUGGESTED A
PATTERN SHIFT WILL BE TAKING PLACE THROUGH THE EXTENDED. THE MEAN
UPPER LEVEL RIDGE IS EXPECTED TO GET FLATTENED AND PUSHED TO THE
SOUTHEAST AS AN UPPER LEVEL LOW MOVES ALONG THE CANADIAN BORDER.
AS THIS SYSTEM MOVES BY LATE IN THE PERIOD...THE RIDGE THEN DOES
NOT BUILD BACK OVER THE ROCKIES NEARLY AS STRONG AS ANOTHER STORM
SYSTEM LOOKS TO BE MOVING ONSHORE WITH MEAN TROUGHING DEVELOPING
ALONG THE WEST COAST KEEPING THE FLOW OVER THE UPPER MIDWEST MORE
OF A ZONAL TO WEAK NORTHWEST PATTERN. AS THE UPPER LEVEL LOW
APPROACHES...THE SURFACE LOW WILL TRACK EAST ALONG THE FRONTAL
BOUNDARY WITH INCREASING FRONTOGENESIS AND ISENTROPIC UP GLIDE.
THIS FORCING WILL COMBINE WITH THE LIFT AHEAD OF THE UPPER LEVEL
LOW AND PROVIDE GOOD FORCING FOR RAIN OVER THE AREA TUESDAY NIGHT
INTO WEDNESDAY NIGHT. THE RAIN CHANCES WILL CONTINUE THURSDAY INTO
FRIDAY BUT WILL BE ON THE DECREASE AS THE SYSTEM MOVES SLOWLY PAST
THE AREA.
&&
.AVIATION...TODAY AND TONIGHT
556 AM CDT SUN JUL 22 2012
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL PERSIST ACROSS THE
AREA THROUGH THE MID MORNING HOURS. A FEW SHOWERS AND PERHAPS AN
ISOLATED THUNDERSTORM COULD IMPACT THE TAF SITES THIS MORNING. WILL
BE INCLUDED -SHRA AND VCTS AT BOTH TAF SITES THROUGH 14Z AT KRST
AND THROUGH 15Z AT KLSE TO ACCOUNT FOR THIS ACTIVITY. IF ANY
THUNDERSTORMS MOVE OVER THE TAF SITES...A BRIEF PERIOD OF MVFR
CONDITIONS WOULD OCCUR WITH CEILINGS LOWERING TO AROUND 2000 FT.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO TAPER OFF LATER THIS
MORNING AS A WARM FRONT LIFTS TO THE NORTH OF THE TAF SITES AND
DRIER AIR ALOFT MOVES IN FROM THE SOUTHWEST. PLAN ON SOUTHWEST
WINDS INCREASING INTO THE 10 TO 15 KTS RANGE. FORECAST SOUNDINGS
ARE SUGGESTING WINDS COULD INCREASE INTO THE 15 TO 20 KT RANGE
WITH GUSTS AROUND 30 KTS POSSIBLE. THE MIXING SEEMS TOO AGGRESSIVE
IN THESE SOUNDINGS WITH SOME CLOUD COVER EXPECTED TO BE IN PLACE
THROUGH MUCH OF THE DAY. WILL HAVE TO MONITOR CLOUD TRENDS AND
MIXING CLOSELY LATE THIS MORNING INTO EARLY THIS AFTERNOON. THERE
IS A SLIGHT CHANCE OF A HIGH BASED SHOWER OR THUNDERSTORMS THIS
AFTERNOON. IF ANY STORMS WOULD DEVELOP...THEY WOULD BE CAPABLE OF
PRODUCING GUSTY WINDS. THINKING THE DRIER AIR MOVING IN SHOULD
KEEP STORMS FROM FORMING THIS AFTERNOON AT THE TAF SITES SO HAVE
NOT INCLUDED ANY SHOWER OR STORM MENTION IN THE THE TAFS AT THIS
TIME. A STRONG INVERSION IS EXPECTED ACROSS THE REGION OVERNIGHT
TONIGHT BRINGING THE POTENTIAL FOR LOW LEVEL WIND SHEAR. SURFACE
WINDS WILL DROP OFF THIS EVENING AS SURFACE HEATING DECREASES. A
MODEST LOW LEVEL JET LOOKS TO SET UP MAINLY AT KLSE TONIGHT WITH
WINDS JUST ABOVE THE SURFACE INCREASING TO AROUND 40 KTS. WILL
HAVE TO CLOSELY MONITOR SURFACE WINDS TONIGHT AND HOW MUCH
DECOUPLING OCCURS. OTHERWISE...PLAN ON VFR CONDITIONS DURING THE
OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
227 AM CDT SUN JUL 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
250 PM MDT SUN JUL 22 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 248 PM MDT SUN JUL 22 2012
RIDGE OVER THE GREAT PLAINS AND TROUGH OVER THE WEST COAST CONTNUE
TO ALLOW A MOIST SOUTHERLY FETCH OVER THE FORECAST AREA THROUGH
THE SHORT TERM PERIOD. A BIT MORE CLOUD COVER THIS MORNING HAS
DELAYED ONSET OF CONVECTION BUT AS CONDITIONS ARE STARTING TO
CLEAR OUT EARLY THIS AFTERNOON ACTIVITY HAS PULSED UP IN THE LAST
HOUR. RUC13 AND WV ARE SHOWING TWO POTENTIAL TRIGGERS IN THIS FLOW
THIS AFTERNOON. ONE IS OVER CENTRAL ARIZONA WHICH IS EXPECTED TO
MOVE EAST ACROSS THE FOUR CORNERS REGION BY LATE THIS AFTERNOON.
THE OTHER IS OVER SOUTHWESTERN COLORADO EARLY THIS AFTERNOON AND
IS EXPECTED TO MOVE SLOWLY NORTHEAST THIS AFTERNOON. THE MAIN
THREAT ONCE AGAIN WILL BE HEAVY RAIN WITH SOME ISOLATED FLASH
FLOODING POSSIBLE...ALONG WITH FREQUENT CLOUD TO RAIN LIGHTNING.
SHOWER AND THUNDERSTORM ACTIVITY WILL DECREASE AFTER MIDNIGHT. BY
MONDAY...PACIFIC NORTHWEST TROUGH WILL MOVE SLOWLY
EAST...OTHERWISE NOT MUCH CHANGE IN WEATHER PATTERN WITH ABUNDANT
MOISTURE IN PLACE...EXPECT ANOTHER ROUND OF SCATTERED TO NUMEROUS
AFTERNOON AND EVENING THUNDERSTORMS WITH THE POTENTIAL FOR HEAVY
RAIN.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 248 PM MDT SUN JUL 22 2012
UPPER CLOSED LOW OVER SRN ALBERTA WILL DRIFT SLOWLY EWRD TUESDAY...
FLATTENING THE RIDGE OF HIGH PRESSURE THAT HAS BEEN OVER OUR REGION.
THIS WILL ALSO USHER IN A WIND SHIFT TO THE NORTHWEST. SOME DYNAMIC
INSTABILITY WILL HELP TO GENERATE ANOTHER AFTERNOON OF WIDESPREAD
CONVECTION TUESDAY AFTERNOON. HOWEVER SIGNIFICANT DRYING ALOFT IS
SEEN FROM THE NORTHWEST TUESDAY NIGHT AND WEDNESDAY. THIS WILL
RESULT IN A NOTABLE DOWNTURN IN CONVECTION WEDNESDAY OVER MOST OF
THE CWA...EXCEPT NEAR AND ALONG THE CONTINENTAL DIVIDE WHERE A
LITTLE DEEPER MOISTURE WILL RESIDE. SHEAR PROFILE ALSO LOOKS LIKE IT
MAY BECOME A LITTLE MORE FAVORABLE FOR STRONGER STORM DEVELOPMENT IN
THAT AREA.
HIGH PRESSURE WILL START TO REBUILD OVER THE SRN GRT BASIN THURSDAY
HELPING HELPING TO SUPPRESS CONVECTION...BUT LOW LEVEL MOISTURE SHOULD
STILL BE IN PLACE FOR AT LEAST ISOLATED STORM DEVELOPMENT. THE NEXT
UPSTREAM TROF IN THE GULF OF ALASKA WILL APPROACH OUR PACIFIC COAST
FRIDAY WHICH WILL PUSH THE ABOVE MENTIONED HIGH PRESSURE CELL
EASTWARD...WHICH WILL THEN ALLOW A SOUTHWESTERLY FLOW TO REDEVELOP.
ACCOMPANYING THIS FLOW WILL BE ANOTHER SURGE OF SUB-TROPICAL
MOISTURE. THIS WILL BRING INCREASING CHANCES OF SHOWER AND
THUNDERSTORM DEVELOPMENT FRIDAY AFTERNOON THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 248 PM MDT SUN JUL 22 2012
DIURNAL HEATING COMBINING WITH ABUNDANT SOUTHERLY FETCH OF MOISTURE
IS GENERATING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WHICH
WILL CONTINUE INTO THE EVENING HOURS ACROSS MUCH OF THE FORECAST
AREA. EXPECT SCATTERED TO NUMEROUS THUNDERSTORM COVERAGE BY LATE
THIS AFTERNOON WHICH WILL RESULT IN FREQUENT MOUNTAIN OBSCURATIONS AND
GUSTY OUTFLOW WINDS FROM 30 TO 40 MPH. REGIONAL AIRPORTS IN CLOSE
PROXIMITY TO HIGHER TERRAIN WILL SEE THE BEST CHANCE OF
THUNDERSTORM ACTIVITY FROM 22Z TO 03Z. THESE STORMS WILL BRING
BRIEF MVFR CIGS AND/OR VSBY IN HEAVY RAIN. SHOWER ACTIVITY WIL
DECREASE OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...MPM
LONG TERM...MC
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1245 PM EDT SUN JUL 22 2012
.SYNOPSIS...
A FRONTAL BOUNDARY FROM NORTH CAROLINA INTO TENNESSEE WILL
DISSIPATE TODAY. HIGH PRESSURE WILL STRETCH FROM THE CENTRAL
PLAINS TO THE SOUTHEAST COAST FROM TONIGHT INTO MONDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTH BY WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1235 PM EDT SUNDAY...
IT TOOK A LITTLE WHILE BUT LOW CLOUDS ARE LIFTING/BREAKING THIS
AFTERNOON AS A WEAK SURFACE WEDGE ERODES. TEMPERATURES WARMING VERY
QUICKLY WHERE THE SUN IS OUT AND SOUTHERLY IS REESTABLISHED TO PUSH
TEMPERATURES INTO THE 80S THIS AFTERNOON. A WEAK LEE TROUGH
ACROSS THE PIEDMONT AND DECAYING SURFACE BOUNDARY OVER NORTH
CAROLINA WILL GENERATE SCATTERED SHOWERS AND THUNDERSTORMS ALONG THE
NC/VA BORDER...EAST OF THE BLUE RIDGE. CAN NOT RULE OUT A STRONG
STORM OR TWO IN THE SOUTH BUT SEVERE THREAT IS KLESS THAN 5
PERCENT.
AS OF 935 AM EDT SUNDAY...
CLOUDY SKIES WILL LINGER THROUGH MUCH OF THE MORNING...THEN SCOUR
DURING THE AFTERNOON. A FEW SHOWERS TRACKING ACROSS THE NORTH
CAROLINA AND GRAYSON HIGHLANDS THIS MORNING. THESE SHOWERS SHOULD
FADE SOME IN AREAL COVERAGE MOVING EAST...THEN REMNANTS/OUTFLOW
BOUNDARIES WILL GENERATE MORE SHOWERS AND THUNDERSTORMS THIS
AFTERNOON. MAJORITY OF THE MODELS HAVE GENEROUS POPS ACROSS RNK
SOUTHERN TIER COUNTIES THIS AFTERNOON. THEREFORE WILL MAINTAIN
SOME SHOWERS IN THE AFTERNOON WHILE KEEPING THE NORTH DRY.
AS OF 415 AM EDT SUNDAY...
RADAR SHOWED ISOLATED SHOWERS FROM SMYTH AND GRAYSON COUNTIES
INTO THE NORTHWEST NORTH CAROLINA MOUNTAINS. THEY REST OF THE
PRECIPITATION FROM EARLIER TONIGHT HAS EITHER DISSIPATED OR MOVED
SOUTHEAST OUT OF THE FORECAST AREA. VAD WIND PROFILES FROM AREA
RADARS SHOWED A NORTH TO NORTHEAST WIND IN THE LOWER 1-4KFT WITH
WEST WINDS ABOVE THIS LAYER. FRONT EXTENDING ACROSS NORTH CAROLINA
AND TENNESSEE WILL CONTINUE TO WEAKEN AND DISSIPATE TODAY WITH THE
WEDGE ERODING AND SURFACE WINDS BECOMING SOUTH TO SOUTHWEST OVER
THE FORECAST AREA BY MID AFTERNOON.
EXPECT LOW CLOUDS TO HOLD IN EAST OF THE BLUE RIDGE THIS MORNING.
EVEN IF COUNTIES IN THE NORTHEAST PART OF THE FORECAST AREA DO NOT
SCATTER OUT UNTIL LATER TODAY...EVEN JUST A COUPLE HOURS OF SUN
WILL BRING TEMPERATURES WELL INTO THE 80S. USED A NON DIURNAL
HOURLY TEMPERATURE FORECAST BASED ON THE GRIDDED LAMP GUIDANCE AND
EXPECTED CLOUD COVER.
FR PROBABILITY OF PRECIPITATION...MODELS HELD ON TO A LOW CHANCE
THIS MORNING. HRRR AND LOCAL WRF SHOWED SHOWERS AND THUNDERSTORMS
DEVELOPING THIS AFTERNOON SOUTH OF HWY 460. ADJUSTED TIMING AND
COVERAGE OF THE PRECIPITATION IN THE SOUTH THIS AFTERNOON.
ONCE STORMS DISSIPATE IN THE EVENING...LITTLE TO NO PRECIPITATION
EXPECTED OVERNIGHT. MAV GUIDANCE LOOKED REASONABLE FOR MINIMUM
TEMPERATURES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SUNDAY...
HEIGHTS INCREASE INTO EARLY NEXT WEEK AS A SLICE OF THE UPPER RIDGE
RESPONSIBLE FOR THE HOT WEATHER ACROSS THE HEARTLAND STRETCHES
EASTWARD. H85 TEMPS WILL RISE TO AROUND +20C. CONSIDERING THE
MOVEMENT OF THE UPPER RIDGE AND ITS POSITION BY TUESDAY ...MOVING
JUST TO OUR SW WHICH WILL DELIVER A DOWNSLOPING NW COMPONENT...TEMPS
MAY VERIFY THE WARMEST GUIDANCE VALUES. MOS HAS BEEN TOO COOL WITH
TEMPS ACROSS THE MIDWEST...AND THIS MAY CONTINUE INTO THE OHIO
VALLEY AND MIDDLE ATLANTIC. GFS/NAM HAVING A HARD TIME PINPOINTING
WHICH DAY WOULD BE BEST FOR AN MCS TO ROLL THROUGH AND INSTEAD HAVE
SEVERAL WAVES OF PRECIP MOVING THROUGH MONDAY THROUGH WEDNESDAY. THIS
PROBABLY HAS LED TO SOME OF THE COOLER MAX TEMPS OFF THE MET. THE
BEST CHANCE FOR AN MCS TO APPROACH OUR REGION LOOKS TO BE LATER
TUESDAY AND TUESDAY NIGHT...AS CORFIDI VECTORS HAVE SUFFICIENT
MAGNITUDE AND DIRECTION TO LEAD SOMETHING TO SE WEST VA FROM THE NW.
ALTHOUGH IT MAY STILL OCCUR...WIDESPREAD STORMS AND HIGH QPF EARLY
TUESDAY LOOKS OVERDONE. NOT ENOUGH CONFIDENCE TO GO LIKELY BUT WILL
KEEP THE HIGHEST POPS IN THE TUESDAY PM AND TUESDAY NIGHT
TIME FRAME...WITH MORE PULSE TYPE STORMS ON MONDAY AND SMALLER POPS.
COLD FRONT DRAPED WEST TO EAST THROUGH THE GREAT LAKES ON TUESDAY
SINKS TO SE WEST VA AND NEAR NW NC INTO WEDNESDAY. THEREFORE THOSE
SPOTS HAVE THE BEST CHANCE OF STORMS CONTINUING INTO MIDWEEK.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 1222 PM EDT SATURDAY...
LOOKS LIKE WE WILL BE STUCK IN A HUMID SOMEWHAT STORMY BUT TYPICAL
LATE JULY PATTERN WITH THE RIDGE STAYING RIGHT ON THE SWRN DOORSTEP
OF OUR REGION...WITH THE BLACKSBURG FORECAST AREA REMAINING ON THE
SRN FRINGE OF THE TROUGH OVER THE NORTHEAST.
WILL BE GOING WITH DAILY THREAT OF SHRA/TSRA BUT WILL SEE ENHANCED
PROBABILITIES AS A SERIES OF SHORTWAVES GRAZE BY...BUT TIMING AT
THIS POINT IS UP IN THE AIR...WITH FRONTAL BOUNDARY SWINGING TOWARD
US IN THE WED-THU TIME FRAME THEN LIFTING NORTH AGAIN BY THE WEEKEND.
LOWS AT NIGHT WILL STAY IN THE 60S IN THE MTNS WITH LOWER 70S EAST
WITH HIGHS IN THE MID-UPPER 80S MTNS TO LOWER TO MID 90S EAST. OF
COURSE ANY CONVECTION AND OR BLOWOFF OF STORMS WILL LIMIT SOME
HEATING FROM TIME TO TIME DURING THE DAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 1245 PM EDT SUNDAY...
SUB VFR CLOUDS STARTED LIFTING ACROSS THE MOUNTAINS AROUND 15Z/11A
SUNDAY. WE WILL SEE THIS TREND IN THE EAST THROUGH EARLY THIS
AFTERNOON. A FRONTAL BOUNDARY ACROSS NORTH CAROLINA BACK INTO THE
TENNESEE VALLEY GENERATING A FEW SHOWERS TOWARD ABINGTON (VJI)
LATE THIS MORNING. WITH THE SUN COMING THROUGH THE CLOUDS...EXPECT
THIS SHOWERS TO CONTINUE TO MOVE EAST AND ALONG THE NC/VA BORDER
INTO THIS EVENING. CONFIDENCE IS LOW THAT ANYONE OF THESE SHOWERS
WILL LOWER CEILINGS BELOW VFR THIS AFTERNOON. THE CHANCES FOR A
THUNDERSTORMS HITTING AN AIRPORT IS ALSO LOW. WILL TIME THE
SHOWERS AS BEST I CAN BUT LEAVE TS AND CB OUT OF THE FORECAST.
FLIGHT PATHS WILL HAVE A BETTER CHANCE OF BEING AFFECTED SOUTH OF
THE VA/NC BORDER.
NW FLOW ALOFT LOOKS TO PERSIST MONDAY THRU THURSDAY...RESULTING
IN BOUTS OF SHRA/TSRA THRU THE PERIOD. OTHERWISE EXPECTING VFR
OUTSIDE OF ANY PERIODS OF THUNDERSTORMS...AND CONTINUED LATE NIGHT
FOG THROUGH MID OR LATE WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/RCS
SHORT TERM...KM
LONG TERM...WP
AVIATION...AMS/RCS
AREA FORECAST DISCUSSION
NWS SPOKANE WA
231 PM PDT Sun Jul 22 2012
.SYNOPSIS...
A strong upper level low will cross the region tonight through
Monday night and result in a chance of thunderstorms for mountain
locations. A few strong storms are possible in the Idaho panhandle
this evening. After the low exits Tuesday, expect a return to dry
and seasonably warm weather for the rest of the week.
&&
.DISCUSSION...
Tonight through Monday: The deep upper level low pressure system is
slowly pushing its way into the Pac NW this afternoon. Water vapor
imagery shows the tightly wound center of the low just southwest
of Vancouver Island with a leading upper level front pushing into
the Cascades. A -24 Celsius cold pool at 500 mbs will accompany
this system as it moves into the Northern Cascades just south of
the Canadian border. This is a fairly anomalous cold pool for mid
July as it is between 2-3 standard deviations colder than what is
average for is time of year and for this region. Models are all in
good agreement moving the center of the low from west to east,
generally right along the Canadian Border. As this system moves
along, we are expecting showers and possibly some thunderstorms to
develop in association with the upper level cold pool in the
northern mountains.
This low is situated at the base of a trough, which is expected to
deepen a bit through this evening. As the trough deepens, we will
see the atmospheric flow pattern become slightly more southerly.
This will allow some monsoonal moisture to ride up northward into
extreme eastern WA and into the Idaho Panhandle. The monsoonal
moisture is reflective of the expansive area of surface convection
and thunderstorms blossoming over southern and central Idaho.
Models have been consistent in showing elevated convection late
this evening into tonight from the northeast Blue Mountains into
the Northern Panhandle and points southeastward. The RUC model
shows increasing 700-850 mb Theta E temperatures across this area,
which is indicative of destabilization of the atmosphere at mid
and upper levels. Dew point temperatures have been falling across
the basin through the afternoon, indicating drier more stable air.
Places like Pullman, Lewiston, Coeur d`Alene and Bonners Ferry
have held on to higher dew points in the low to mid 50s, compared
to dew points in the 40s for places like Moses Lake and Spokane.
This makes me more confident that any convection tonight across
the southeast will not make it much further westward than the
Spokane Area.
Winds will pick up tonight with the passage of the cold front.
Expect these winds to pick up in the Wenatchee Area first in the
early evening hours and then spread eastward into the basin
tonight. winds will be sustained at around 15 to 25 mph with gusts
as high as 25 to 35 mph. Wenatchee could be even slightly more
windy with strong cold air advection through the Cascade gaps this
evening. High temperatures tomorrow will be well below average
with highs expected to be in the 70s for most valley locations.
The northern valleys will have a hard time breaking 70 due to
cloud cover and precipitation. /SVH
Monday night through Wednesday...The next closed upper level low
will slowly track northeast-east and in to Alberta Monday night.
Behind the exiting low the flow will turn northwest. The 00z and
now the 12z models runs are now picking up on another much weaker
low pressure system forming just of Vancouver Island Tuesday, then
deepening as it moves into northwest Washington Tuesday night and
Wednesday. This is a little bit different solution than what we
saw yesterday.
Monday night and Tuesday. As the low kicks out of the region
Monday night moisture will wrap around the low. There isn`t much
in the way of dynamical lift left, save for some orographics. But
there will be some lingering instability and this will support
isolated showers across the northern mountains through the night.
There will be enough instability across north Idaho for an
outside chance of a thunderstorm through the evening hours.
Showers will be on the decrease through the night and Tuesday
morning. Both surface based and ML cape increase through the day
again Tuesday. And while the cape is capped there will be an
opportunity for showers across the northern tier of zones late in
the afternoon. 850 temps increase to 17-18C and with mostly sunny
skies temperatures should show a rebound over the cooler
temperatures from Monday.
Tuesday night and Wednesday the low off Vancouver island begins to
deepen as it moves off the coast. This will swing the upper level
flow back around to the southwest and allow some Pacific moisture
back into the northern mountains. Surface based cape increases to
around 500 J/kg, LI`s -1 to -2 and 700-500 theta e lapse rates
decrease across the north cascades and northern mountains. So
instability is only marginal and there is no decent forcing
mechanism. The models are picking up on a few little waves in the
southwest flow, but these look to be pretty weak. Still, there
will be a chance of surfaced based convection and isolated showers
and a few embedded thunderstorms in the late afternoon.
Temperatures will continue to increase and should be near normal
by Wednesday. /Tobin
Wednesday night through Sunday: A long-wave trough migrates to
the B.C. coast and keeps the Inland Northwest under a dirty ridge,
as weak shortwaves slip in on the southwest flow. This will bring
occasional clouds to the CWA, a lingering threat of mainly
mountains showers and thunderstorms, and warmer temperatures.
Temperatures are expected to warm to average and slightly above
through the period. Guidance shows 850mb temperatures peaking
Thursday and Friday, with a slight cooling trend next weekend
behind the one shortwave, and surface temperatures are forecast to
follow this same trend.
One shortwave, which was coming across the southern Gulf of
Alaska Sunday evening, arrives at the Pacific Northwest coast
Wednesday evening. As the aforementioned long-wave trough migrates
toward the B.C. coast through the end of the work week, the
shortwave is drawn across the CWA. Per the PWAT projections,
moisture pools near the Canadian border and Cascades Wednesday
night through Friday and increases across the southeast CWA
Thursday afternoon and Friday. PWATs rise to between 110-130% of
normal. Models also indicate some low-grade instability. SBCAPE
values between 100-400 J/kg are indicated across the northern
third of the CWA Wednesday evening and again Thursday afternoon
and evening. The passing impulse and upslope flow will help bring
the shower and thunderstorm threat to these areas. Similar SBCAPE
values come into the southeast CWA Thursday afternoon and evening,
from the Blues to Central Panhandle Mountains and will lead to
some shower and thunderstorm threat here too.
By Friday the best moisture and instability retreats into the far
southeast CWA and against the northern Cascades. This leaves the
primary shower potential across northwest Okanogan county, the
Blues, southeast Shoshone county and the Camas Prairie. Guidance
currently indicates CIN values between 100-200 J/kg from the Blues
through the Camas Prairie and southwest Shoshone county, which
would likely inhibit the convection. However there is potential
for showers to develop south of here, where the CIN is weak, and
advect into these areas before falling apart.
Additionally low-end breezy conditions are expected with the
passing wave, especially Friday. At this time, however, relative
humidities and sustained wind speeds are not expected to result in
red flag conditions.
By Saturday the region is under drier, more stable air, lending
to a dry forecast. Then by Sunday another potential shortwave
impulse and injection of monsoonal moisture will return a threat
of showers to the mountains, particularly the far southeast.
Models are not in good agreement with the track and timing of this
potential shortwave, so PoPs are decidedly low. /J. Cote`
&&
.AVIATION...
18z TAFS: A low pressure system will push through a cold front
late this afternoon through this evening. This will result in
increasing westerly winds, beginning with KEAT after 22Z and
spread eastward reaching the Panhandle by 02Z early this evening. We
will likely see some wind gusts up to around 25 to 35 mph through
the evening. We should then lose the gusts as we decouple tonight
with possibly some weak low level wind shear. Winds are expected
to relax a bit by tomorrow morning. Showers and thunderstorms will
remain across the northern mountains this afternoon. Some moisture
moving up from the south may produce some elevated thunderstorms
across the Northeast Blues into the Northern Panhandle by late
this evening. However, there is some question if we will get this
moisture, so confidence is low at this point. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 53 72 54 81 57 85 / 10 10 0 0 0 10
Coeur d`Alene 55 71 52 80 53 83 / 20 10 10 10 10 10
Pullman 49 73 47 79 50 84 / 20 0 0 0 0 0
Lewiston 60 83 56 89 59 92 / 30 0 0 0 0 0
Colville 56 75 52 83 55 86 / 20 30 10 10 10 20
Sandpoint 54 71 49 80 51 83 / 40 30 20 10 10 10
Kellogg 56 69 49 77 53 82 / 40 10 10 10 10 10
Moses Lake 55 79 54 86 57 90 / 10 0 0 0 0 0
Wenatchee 58 80 57 86 61 90 / 10 0 0 0 10 0
Omak 56 77 52 86 57 89 / 30 20 10 10 10 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
311 PM CDT SUN JUL 22 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
311 PM CDT SUN JUL 22 2012
THE MAIN FOCUS GOING THROUGH MID WEEK IS WITH THE PRECIPITATION
CHANCES AND HOW WARM IT WILL GET TOMORROW.
LITTLE TO NO CHANGE TO THE UPPER LEVEL PATTERN AS A LARGE...YET
FLAT RIDGE OF HIGH PRESSURE REMAINS CENTERED ON THE CENTRAL
PLAINS. THE FOCUS FOR ANY PRECIPITATION CHANCES HAS BEEN WITH ANY
MID LEVEL SHORT WAVE TROUGHS THAT HAVE DROPPED DOWN FROM THE
NORTHWEST FROM THE DAKOTAS. THIS MORNINGS SHORT WAVE HAS
PROPAGATED OFF TO THE EAST WITH A CLOSED MID LEVEL LOW TRACKING
EAST ACROSS SOUTH CENTRAL CANADA. THIS MORE POTENT MID LEVEL LOW
HAS LED TO STRONGER SOUTHERLY LOW LEVEL FLOW WITH ONE SURFACE
LOW/LEFT OVER MCV OVER SOUTHERN MINNESOTA AND A DEEPER LOW NORTH
OF WINNIPEG.
THE INITIAL FOCUS FOR THE REST OF THIS AFTERNOON AND EVENING IS
WITH THE WARM FRONT THAT EXTENDS EAST OUT OF THE MCV LOW TOWARD
EAU CLAIRE AND HAS BEEN LIFTING NORTH THROUGH THE AFTERNOON. SKIES
HAVE CLEARED ACROSS MUCH OF NORTHERN IOWA WITH SCATTERED
CONVECTION/CLOUD COVER STILL OVERHEAD THROUGH MUCH OF SOUTHERN
MINNESOTA AND WESTERN WISCONSIN. WITH INVERTED V SOUNDINGS NOTED
FROM THE WARM SECTOR WHERE SURFACE TEMPERATURES QUICKLY JUMPED
INTO THE 90S...THE CONCERN IS THAT SOME SURFACE BASED STORMS WILL
BE IGNITED AS THE MCV MOVES IN AND BRINGS SOME STRONG WINDS ALONG
WITH IT. THIS AFTERNOON/S HRRR RUNS HAVE BEEN HITTING WESTERN
WISCONSIN HARDER WITH CONVECTION ALONG THE WARM FRONT WHICH
APPEARS TO BE OVERDONE. WHILE CONFIDENCE IS LOW WITH HOW THE REST
OF THIS AFTERNOON AND EVENING WILL PAN OUT...THERE APPEARS TO BE
ENOUGH OF A THREAT TO CARRY SOME CHANCES FOR PRECIPITATION INTO
THE EVENING.
BEYOND TONIGHT...THE MAIN COLD FRONT DROPS SOUTH TOMORROW AND
BECOMES STATIONARY IN NORTHERN IOWA BY TOMORROW NIGHT. THIS
FEATURE MAY BE ENOUGH OF A KICKER TO INITIATE CONVECTION ALONG IT
TOMORROW DESPITE HIGH LFC/S AND LACK OF UPPER LEVEL SUPPORT.
WITH INCREASING 850-500MB FRONTOGENESIS ALONG THIS FRONTAL
ZONE...ADDED SOME SMALL SHOWER/STORM CHANCES TOMORROW AFTERNOON
AND INCREASED THE EVENING CHANCES. SEVERE WEATHER DOES NOT LOOK
VERY LIKELY...BUT INVERTED V SOUNDINGS OUT AHEAD OF THE FRONT
COULD LEAD TO SOME GUSTY WINDS WITH SOME OF THE STORMS THAT DO
MANAGE TO DEVELOP.
WITH THE COLD FRONT BRINGING SOME CLOUD COVER ALONG WITH IT AND
DEEP AFTERNOON MIXING LEADING TO DRYING DEW POINTS...IT DOES NOT
APPEAR AS THOUGH HEAT INDICES WILL WARM UP MUCH BEYOND 100 DEGREES.
THE MISSISSIPPI AND WISCONSIN RIVER VALLEYS MAY BE THE EXCEPTION
WHERE TEMPERATURES WILL BE A FEW DEGREES HIGHER. AFTER COLLABORATION
WITH NEIGHBORING OFFICES...HAVE DECIDED TO NOT ISSUE A HEAT
ADVISORY FOR TOMORROW ACROSS NORTHEAST IOWA/SOUTHWEST WISCONSIN.
THE BAROCLINIC ZONE ALONG THE FRONT BECOMES MORE ACTIVE MONDAY
NIGHT THROUGH WEDNESDAY AS THE LOW LEVEL FRONTOGENESIS STAYS
STRONG AND THE LOW LEVEL MOISTURE TRANSPORT INCREASES. CONFIDENCE
IS PRETTY HIGH THAT SOME MORE SIGNIFICANT RAINS WILL COME AS THIS
PATTERN SETS UP...PARTICULARLY AT NIGHT WHEN THE LOW LEVEL JET
DEVELOPS AND NOSES UP INTO THE REGION. CAN NOT RULE OUT SOME
SEVERE WEATHER OVER THIS TIME FRAME AS WELL WITH UNSTABLE AIR
POOLING ALONG THE FRONT ALONG WITH DECENT DEEP LAYER
SHEAR...PARTICULARLY IF THE BOUNDARY HANGS UP ACROSS THE AREA IN
NORTHEAST IOWA AND NOT TO THE SOUTH AS FORECAST. THE BETTER
CHANCES FOR ORGANIZED CONVECTION MAY BE ON TUESDAY NIGHT INTO
WEDNESDAY AS A MID LEVEL SHORT WAVE TROUGH COMES THROUGH AND
BRINGS A LOW ALONG THE STATIONARY FRONT.
.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY NIGHT
311 PM CDT SUN JUL 22 2012
THE STATIONARY FRONT WILL GET A KICK TO THE SOUTH IN THE WAKE OF
THE SURFACE LOW THAT COMES THROUGH ON WEDNESDAY THOUGH CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL PERSIST INTO FRIDAY AS A CLOSED MID
LEVEL LOW DROPS SOUTHEAST FROM THE NORTHERN PLAINS INTO THE GREAT
LAKES. RIDGING THEN MOVES IN FROM THE WEST FRIDAY NIGHT INTO
SATURDAY AT THE SURFACE AND ALOFT AND SHOULD BRING DRIER
CONDITIONS ALONG WITH IT. TEMPERATURES LOOK SEASONAL IN THE LOW TO
MID 80S ACROSS THE REGION WITH 850MB TEMPERATURES DROPPING INTO
THE +15C AREA.
&&
.AVIATION...THROUGH 18Z MONDAY
1243 PM CDT SUN JUL 22 2012
CURRENTLY WATCHING A WEAKENING MID-LEVEL TROUGH WHICH CAUSED
OVERNIGHT/MORNING CONVECTION ROTATE EAST OF THE RIVER. AS A
RESULT...BULK OF SHRA/ISOLD TS ACTIVITY NOW EAST OF THE TAF SITES.
OTHERWISE...A SURFACE WARM FROM WAS LOCATED FROM NEAR THE TWIN
CITIES AND THEN SOUTHEAST APPROXIMATELY ALONG I-94. SOUTH WINDS
HAVE BEEN PICKING UP IN THE WARM SECTOR AT KRST/KLSE THE LAST
COUPLE OF HOURS WITH SOME GUSTINESS EXPECTED THROUGH THE AFTERNOON
TO AROUND 20-25KT AT KRST. KLSE EXPECTED TO STAY IN THE 10-15KT
RANGE. SKY COVER EXPECTED TO BE SCATTERED AC/ACCAS IN BROAD WARM
AIR ADVECTION. OVERNIGHT PERIOD LOOKS RELATIVELY QUIET WITH
SCATTERED AC/ACCAS CONTINUING AND WINDS SLACKENING. WINDS WILL
START VEERING TO THE WEST/NORTHWEST MONDAY MORNING IN THE 14-15Z
TIME FRAME AS A SURFACE COLD FRONT MOVES SOUTHEAST THROUGH THE
AREA. ONCE THE FRONT SLIPS JUST SOUTH OF THE AREA IT IS EXPECTED
TO STALL OUT ACROSS NORTHERN IA/IL. ANOTHER WEAK MID-LEVEL TROUGH
IS THEN EXPECTED TO INTERACT WITH THIS FRONTAL BOUNDARY BY MONDAY
AFTERNOON FOR A CHANCE OF SHRA/TS...WITH MOST OF THIS ACTIVITY
EXPECTED TO REMAIN SOUTH OF THE TAF SITES. OTHERWISE...APPEARS VFR
CONDITIONS WILL PREVAIL THROUGH MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
311 PM CDT SUN JUL 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
308 PM CDT SUN JUL 22 2012
.SHORT TERM...
.TONIGHT AND MONDAY...FORECAST CONFIDENCE IS MEDIUM.
WIDELY SCATTERED SHOWERS HAVE BEEN MOVING INTO AREAS WEST OF MADISON
ALL DAY...AND HAVE DIMINISHED WITH DRY AIR IN LOW LEVELS OF THE
ATMOSPHERE. THESE SHOWERS DRIVEN BY LOW LEVEL JET NOSE/WARM AIR
ADVECTION AND PASSING VORTICITY MAXIMUM. ANOTHER VORTICITY MAXIMUM
IN SOUTHWEST MINNESOTA SHOULD SHIFT EAST ACROSS THE AREA THROUGH
THIS EVENING. IN ADDITION...LOW LEVEL JET NOSE SHIFTS EAST ACROSS
THE AREA THIS EVENING...WITH FOCUSED WARM AIR ADVECTION.
AREA FORECAST SOUNDINGS FROM NAM SHOWING ELEVATED CAPES ONLY UP TO
500 J/KG...WITH GOOD DEEP LAYER SHEAR. MEAN LAYER CAPE MUCH HIGHER
ON RAP ANALYSIS...BUT DEWPOINTS SEEM OVERDONE BY SEVERAL DEGREES.
LEVEL OF FREE CONVECTION NEAR 700MB AS WELL...WITH A BIT OF A CAP TO
WORK THROUGH. INVERTED V TYPE STRUCTURE TO SOUNDINGS DO INDICATE
DOWNBURST WIND POTENTIAL IF ANY DECENT CELLS DEVELOP. MESOSCALE
MODELS DIFFER A FAIR AMOUNT WITH TRENDS THROUGH THE NIGHT.
GIVEN SOME UNCERTAINTY WITH EXACT EVOLUTION OF POSSIBLE
CONVECTION...WITH GO WITH CHANCE POPS FOR THUNDER THROUGH THE
EVENING...LINGERING IN THE SOUTHEAST AFTER 06Z MONDAY.
OTHERWISE...MID LEVEL CLOUDS SHOULD LINGER...WITH MILD LOWS IN THE
70S ACROSS MOST OF THE AREA.
WEST SOUTHWEST WINDS AHEAD OF COLD FRONT PULL HOT AIRMASS INTO THE
AREA. 925MB TEMPERATURES FROM NAM SUGGEST HIGHS OF AROUND 100 OR A
BIT HIGHER...BUT SHOULD HAVE AT LEAST SOME MID LEVEL CLOUDS IN THE
AREA WITH PASSING VORTICITY MAXIMUM. WITH UNCERTAINTY WITH AMOUNT OF
CLOUDS IN THE AREA...OPTED TO GO MID TO UPPER 90S FOR HIGHS...WHICH
KEEPS HEAT INDEX VALUES JUST UNDER 100. THUS...WILL HOLD OFF ON A
HEAT ADVISORY FOR NOW.
ALSO...WEAK COLD FRONT DROPPING SOUTHEAST INTO THE AREA DURING THE
AFTERNOON MAY HELP GENERATE SHOWERS AND A FEW STORMS. SOMEWHAT
BETTER MEAN LAYER CAPES WITH GOOD DEEP LAYER SHEAR EXPECTED...BUT
WILL HAVE TO AGAIN REACH NEAR 700MB LEVEL OF FREE CONVECTION. SLIGHT
CHANCES FOR THUNDER SEEM REASONABLE FOR NOW.
.MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
THE NEAR 100 KNOT JET MAX NEAR LAKE SUPERIOR MONDAY EVENING WILL
WEAKEN A BIT AS IT REACHES LAKE HURON EARLY TUESDAY MORNING...WITH
WISCONSIN IN A NORTHWEST MID/UPPER FLOW. THERE IS SOME 250 MB UPPER
DIVERGENCE MONDAY NIGHT ACROSS SOUTHERN WISCONSIN...WITH SOME
CONVECTIVE FEEDBACK ON THE NAM GIVING SEVERAL BULLS EYES OF MORE
MODERATE DIVERGENCE.
THE SURFACE BOUNDARY IS PUSHED SOUTH ACROSS EASTERN IOWA AND
FAR NORTHERN ILLINOIS TUESDAY NIGHT...THEN ACROSS CENTRAL ILLINOIS
TO SOUTHERN INDIANA LATE MONDAY EVENING. THE 925/850 MB THERMAL
RIDGE IS PUSHED TO THE SOUTH OF WISCONSIN ROUGHLY PARALLELING THE
SURFACE BOUNDARY. THE 700 MB RELATIVE HUMIDITY IS FAIRLY HIGH
MONDAY NIGHT WITH MODERATE 700 MB UPWARD MOTION AROUND 11 MICROBARS/SEC
ALONG AND JUST NORTH OF THE BOUNDARY...WHILE THE 700 MB MOISTURE
CONVERGENCE IS HIGHEST ACROSS SOUTHERN WISCONSIN.
THE FORECAST SOUNDINGS ARE FAIRLY MOIST WITH PRECIPITABLE WATER
VALUES AROUND 2 INCHES ACROSS MUCH OF THE FORECAST AREA. SOME
ELEVATED CAPE OF AROUND 1000 J/KG ALSO EXISTS DURING THE
EVENING...BUT THIS IS IF LIFTED FROM JUST ABOVE THE DEVELOPING
NOCTURNAL INVERSION. GIVEN ALL THIS WILL CONTINUE THE CHANCE OF
THUNDERSTORMS.
.TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
THE MID/UPPER FLOW BECOMES MORE WEST WEDNESDAY AS THE SOUTHWEST
CANADIAN MID/UPPER LOW MOVES INTO SOUTHERN SASKATCHEWAN...THEN
TOWARDS LAKE WINNIPEG. THERE IS MODERATE UPPER DIVERGENCE ACROSS
MUCH OF THE FORECAST AREA TUESDAY NIGHT...THEN EXITING TO THE EAST
BY NOON WEDNESDAY. MODERATE 700 MB MOISTURE CONVERGENCE OF UP TO
20 G/KG/12 HOUR EXTENDS ACROSS THE FORECAST AREA TUESDAY NIGHT
INTO WEDNESDAY. THE 850 MB FLOW BECOMES SOUTHWEST MAINLY JUST TO
OUR SOUTH WITH AROUND 10 G/KG/12 HOUR VALUES OF 850 MB MOISTURE
CONVERGENCE. 800 AND 700 MB LI`S ARE AROUND -3 TUESDAY NIGHT AND
WEDNESDAY WITH ELEVATED CAPE AROUND 800 J/KG LIFTED FROM THE
MOISTURE LAYER AT 8 THSD FT. PRECIPITABLE VALUES REMAIN AROUND 2
INCHES OVER MUCH OF THIS TIME FRAME...WITH MOST MODELS INDICATING
PRECIPITATION WITH MODERATE AMOUNTS AROUND 0.50 INCH.
THE NORTHERN PORTION OF THE 850 MB THERMAL RIDGE DOES PUSH INTO
EASTERN IOWA AND NORTHERN ILLINOIS WITH THE SOUTHWEST PORTIONS OF
THE FORECAST AREA ON THE NOSE OF THE THERMAL RIDGE WITH TEMPERATURES
NEAR 24 CELSIUS.
THE 12Z NAM AND 06Z DGEX KEEPS THE SURFACE FRONT ACROSS IOWA AND
NORTHERN ILLINOIS. HOWEVER THE 12Z GFS AND 00Z ECMWF DOES PUSH A
WARM FRONT INTO SOUTHWEST PORTIONS OF THE FORECAST AREA FROM NEAR
MADISON TO JANESVILLE. THICKNESS VALUES ARE NEAR 582 DECAMETERS ON
MOST OF THE MODELS NEAR THE ILLINOIS BORDER.
FAIRLY DECENT PRECIPITATION CHANCES DURING THIS TIME FRAME.
THE LOCAL CWASP SEVERE WEATHER INDEX HAS VALUES NEAR 60 PERCENT
ON THE GFS WEDNESDAY AFTERNOON WHILE THE NAM HAS IT CLOSER TO THE
LOW OVER NORTHERN MINNESOTA...WHICH SEEMS TO BE MORE REASONABLE.
.LONG TERM...
.WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
BY THURSDAY THE UPPER LOW/TROUGH AXIS REACHES FAR NORTHERN
MINNESOTA.
THE SURFACE LOW PATTERN HAS A DOUBLE LOW STRUCTURE WITH ONE LOW
NEAR THE BOUNDARY AND ANOTHER CLOSER TO THE MID LEVEL TROUGH.
FAIRLY DECENT PRECIPITATION CHANCES CONTINUE WEDNESDAY NIGHT INTO
THURSDAY.
.FRIDAY AND SATURDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
THE ECMWF AND GFS TAKES THE UPPER TROUGH ACROSS THE GREAT LAKES
FRIDAY AND OFF TO THE NORTHEAST U.S. AND SOUTHEAST CANADA
SATURDAY.
BOTH THE GFS AND ECMWF BRINGS SOME INSTABILITY SHOWERS FRIDAY
BEFORE HIGH PRESSURE EXTENDS ACROSS THE UPPER MISSISSIPPI VALLEY
AND WESTERN GREAT LAKES SATURDAY.
.SUNDAY...FORECAST CONFIDENCE MEDIUM.
A MORE ZONAL FLOW RETURNS ACROSS THE NORTHERN U.S. ON SUNDAY. THE
12Z GFS AND 06Z DGEX ARE DRY...BUT THE 00Z/12Z ECMWF HAS SOME
PRECIPITATION IN THE RETURN WARM AIR ADVECTION REGION GETTING
INTO PORTIONS OF SOUTHERN WISCONSIN. WILL LEAN TOWARDS A CONSENSUS
FORECAST.
&&
.AVIATION/00Z TAFS/...
VFR CONDITIONS EXPECTED THROUGH MONDAY ACROSS TAF SITES. BROKEN
MIDDLE TO HIGH CLOUDS SHOULD CONTINUE TO SPREAD ACROSS TAF SITES
LATE THIS AFTERNOON...AND LINGER TONIGHT. ANY SHOWERS AND
THUNDERSTORMS THAT TRY TO FORM AND MOVE THROUGH SOUTHERN WISCONSIN
DURING THIS TIME WILL HAVE TO BATTLE DRIER LOW LEVEL AIRMASS OVER
THE AREA. THERE SHOULD STILL BE ENOUGH LIFT WITH LOW LEVEL JET
STREAM TO BRING CHANCES FOR SHOWERS AND THUNDERSTORMS AROUND TAF
SITES. CONFIDENCE IS LOW IN EXACT TIMING...SO USED VICINITY WORDING
IN TAFS FOR NOW.
POSSIBILITY FOR LOW LEVEL WIND SHEAR BETWEEN 04Z AND 09Z WITH 40
KNOT PLUS WINDS AT 2000 FEET ABOVE GROUND LEVEL. CONFIDENCE LOW IN
THE MAGNITUDE OF THESE WINDS...SO LEFT MENTION OUT OF TAFS FOR NOW.
LIGHT TO MODERATE SOUTH SOUTHWEST WINDS BY 00Z MONDAY SHOULD BECOME
SOUTHWEST LATER TONIGHT...AND WESTERLY ON MONDAY. HOT AIRMASS MONDAY
EXPECTED. COLD FRONT PASSING SOUTHEAST THROUGH THE AREA DURING THE
AFTERNOON WILL BRING SLIGHT CHANCES OF SHOWERS AND
THUNDERSTORMS...BUT LEFT MENTION OUT OF TAFS FOR NOW DUE TO LOW
CONFIDENCE IN TIMING AND COVERAGE. SCATTERED TO BROKEN MID LEVEL
CLOUDS SHOULD CONTINUE INTO MONDAY AS WELL.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...WOOD
MONDAY NIGHT THROUGH SUNDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1243 PM CDT SUN JUL 22 2012
.SHORT TERM...THROUGH TUESDAY
227 AM CDT SUN JUL 22 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS MORNING SHOWED A WEAK AREA OF LOW
PRESSURE OVER SOUTH DAKOTA WITH A WARM FRONT EXTENDING EAST ACROSS
SOUTHERN MINNESOTA INTO CENTRAL WISCONSIN. LOCAL AND REGIONAL
RADARS SHOWING A COMPLEX OF SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF THE BOUNDARY OVER SOUTHERN MINNESOTA.
WATER VAPOR IMAGERY LOOP SHOWS A WEAK SHORT WAVE TROUGH OVER
WESTERN MINNESOTA HELPED TO SPARK THE CONVECTION THIS MORNING. THE
22.03Z RAP BRINGS THIS SHORT WAVE TROUGH ACROSS THE AREA ON ITS
WAY TO THE SOUTHERN TIP OF LAKE MICHIGAN BY LATE MORNING. THE WAVE
IS PRODUCING AROUND 4 PVU/S OF VORTICITY ADVECTION IN THE 500-300
MB LAYER AND IS EXPECTED TO CONTINUE DOING SO AS IT MOVES
OVERHEAD. THE LOW LEVEL MOISTURE TRANSPORT INTO THE ACTIVITY IS
EXPECTED TO GRADUALLY TURN TO THE SOUTHWEST THE FARTHER EAST THE
ACTIVITY GETS...BUT SHOULD CONTINUE TO FEED INTO IT UNTIL AFTER
SUNRISE. WILL CONTINUE TO MONITOR RADAR TRENDS BUT THINKING THERE
SHOULD BE DECENT COVERAGE OF SHOWERS FOR AREAS WEST OF THE
MISSISSIPPI RIVER FOR THE FIRST HALF OF THE MORNING. COVERAGE
SHOULD THEN START TO DIMINISH AS THE MOISTURE FEED STARTS TO
WEAKEN WITH ONLY SOME WIDELY SCATTERED ACTIVITY LEFT OVER FOR THE
AFTERNOON.
ONCE THE FRONT GOES THROUGH TODAY...IT WILL BECOME STATIONARY JUST
SOUTH OF THE AREA AND BECOME THE FOCUS FOR THE REMAINDER OF THE
PERIOD. THE 22.00Z NAM...AND TO A LESSER DEGREE...THE 21.12Z ECMWF
SHOW THE FRONTOGENESIS GRADUALLY INCREASING AND BECOMING DEEPER
ALONG THE FRONT STARTING MONDAY. BY LATE MONDAY NIGHT INTO TUESDAY
MORNING...THE FRONTOGENESIS IS EXPECTED TO BE MODERATE IN
STRENGTH IN THE 1000-850 MB LAYER AND WEAK IN THE 850-500 MB
LAYER. THE NEXT SURFACE LOW WILL BE TAKING SHAPE OVER NEBRASKA OR
SOUTH DAKOTA ALONG THE WESTERN PART OF THE FRONT. AS THIS
CONTINUES TO DEVELOP...THE LOW LEVEL WARM AIR ADVECTION OVER THE
FRONT WILL BE INCREASING WITH THE ECMWF SHOWING AROUND 2 UBAR/S
OF UP GLIDE ON THE 315K ISENTROPIC SURFACE OVER THE FRONT. THESE
HAVE BEEN CONSISTENT SIGNALS SO HAVE RAISED THE RAIN CHANCES UP TO
50 PERCENT FOR A GOOD SHARE OF THE AREA NORTH OF THE FRONT. THE
MOISTURE TRANSPORT INTO THE FRONT DOES NOT LOOK TO BE VERY STRONG
WITH BOTH THE NAM AND ECMWF SUGGESTING IT WILL BE MORE PARALLEL TO
THE FRONT INSTEAD OF INTO IT. THE FORCING THEN STARTS TO WEAKEN
BUT DOES NOT TOTALLY DISSIPATE TUESDAY AFTERNOON SO MAINTAINED A
30 PERCENT CHANCE FOR MUCH OF THE AREA.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
227 AM CDT SUN JUL 22 2012
BOTH THE 21.12Z AND 22.00Z RUNS OF THE ECMWF HAVE SUGGESTED A
PATTERN SHIFT WILL BE TAKING PLACE THROUGH THE EXTENDED. THE MEAN
UPPER LEVEL RIDGE IS EXPECTED TO GET FLATTENED AND PUSHED TO THE
SOUTHEAST AS AN UPPER LEVEL LOW MOVES ALONG THE CANADIAN BORDER.
AS THIS SYSTEM MOVES BY LATE IN THE PERIOD...THE RIDGE THEN DOES
NOT BUILD BACK OVER THE ROCKIES NEARLY AS STRONG AS ANOTHER STORM
SYSTEM LOOKS TO BE MOVING ONSHORE WITH MEAN TROUGHING DEVELOPING
ALONG THE WEST COAST KEEPING THE FLOW OVER THE UPPER MIDWEST MORE
OF A ZONAL TO WEAK NORTHWEST PATTERN. AS THE UPPER LEVEL LOW
APPROACHES...THE SURFACE LOW WILL TRACK EAST ALONG THE FRONTAL
BOUNDARY WITH INCREASING FRONTOGENESIS AND ISENTROPIC UP GLIDE.
THIS FORCING WILL COMBINE WITH THE LIFT AHEAD OF THE UPPER LEVEL
LOW AND PROVIDE GOOD FORCING FOR RAIN OVER THE AREA TUESDAY NIGHT
INTO WEDNESDAY NIGHT. THE RAIN CHANCES WILL CONTINUE THURSDAY INTO
FRIDAY BUT WILL BE ON THE DECREASE AS THE SYSTEM MOVES SLOWLY PAST
THE AREA.
&&
.AVIATION...THROUGH 18Z MONDAY
1243 PM CDT SUN JUL 22 2012
CURRENTLY WATCHING A WEAKENING MID-LEVEL TROUGH WHICH CAUSED
OVERNIGHT/MORNING CONVECTION ROTATE EAST OF THE RIVER. AS A
RESULT...BULK OF SHRA/ISOLD TS ACTIVITY NOW EAST OF THE TAF SITES.
OTHERWISE...A SURFACE WARM FROM WAS LOCATED FROM NEAR THE TWIN
CITIES AND THEN SOUTHEAST APPROXIMATELY ALONG I-94. SOUTH WINDS
HAVE BEEN PICKING UP IN THE WARM SECTOR AT KRST/KLSE THE LAST
COUPLE OF HOURS WITH SOME GUSTINESS EXPECTED THROUGH THE AFTERNOON
TO AROUND 20-25KT AT KRST. KLSE EXPECTED TO STAY IN THE 10-15KT
RANGE. SKY COVER EXPECTED TO BE SCATTERED AC/ACCAS IN BROAD WARM
AIR ADVECTION. OVERNIGHT PERIOD LOOKS RELATIVELY QUIET WITH
SCATTERED AC/ACCAS CONTINUING AND WINDS SLACKENING. WINDS WILL
START VEERING TO THE WEST/NORTHWEST MONDAY MORNING IN THE 14-15Z
TIME FRAME AS A SURFACE COLD FRONT MOVES SOUTHEAST THROUGH THE
AREA. ONCE THE FRONT SLIPS JUST SOUTH OF THE AREA IT IS EXPECTED
TO STALL OUT ACROSS NORTHERN IA/IL. ANOTHER WEAK MID-LEVEL TROUGH
IS THEN EXPECTED TO INTERACT WITH THIS FRONTAL BOUNDARY BY MONDAY
AFTERNOON FOR A CHANCE OF SHRA/TS...WITH MOST OF THIS ACTIVITY
EXPECTED TO REMAIN SOUTH OF THE TAF SITES. OTHERWISE...APPEARS VFR
CONDITIONS WILL PREVAIL THROUGH MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
227 AM CDT SUN JUL 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...DAS