Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/09/12
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
850 AM MST TUE AUG 7 2012
.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL OVER THE DESERT SOUTHWEST THIS
WEEK...RESULTING IN WELL ABOVE NORMAL TEMPERATURES AND PERIODS OF
EXCESSIVE HEAT. THUNDERSTORM CHANCES WILL BE FOCUSED MAINLY OVER
HIGHER TERRAIN OF NORTHERN AND EASTERN ARIZONA TODAY...THOUGH THERE
WILL BE A CHANCE OF STORMS WEDNESDAY AND THURSDAY ACROSS
SOUTH-CENTRAL ARIZONA. THE WELL ABOVE NORMAL TEMPERATURES WILL
PERSIST THROUGH AT LEAST THE WEEKEND ALONG WITH BELOW NORMAL CHANCES
FOR RAIN AND THUNDERSTORMS.
&&
.DISCUSSION...
CURRENT FORECAST STILL IN GOOD SHAPE AS HOT TEMPERATURES WILL BE THE
DOMINANT FEATURE TODAY AND THROUGH THE REST OF THE WEEK. THE VORT
MAX OVER NORTHWEST SONORA MEXICO CONTINUES TO TRACK WEST NORTHWEST
JUST SOUTH OF ARIZONA. A FEW ISOLATED SHOWERS ON THE NORTH SIDE OF
THE VORT MAX WILL STILL BE POSSIBLE ACROSS SOUTHERN YUMA COUNTY
THROUGH THE REST OF THE MORNING...BUT LIKELY ONLY RESULTING IN
SPRINKLES OR NON-MEASURABLE AMOUNTS. ADDITIONAL DEVELOPMENT WILL BE
POSSIBLE THROUGH THE REST OF TODAY ASSOCIATED WITH THIS
FEATURE...BUT THE LOW END SLIGHT CHANCE IN PORTIONS OF FAR SOUTHEAST
CALIFORNIA STILL LOOKS REASONABLE. MAY HAVE TO INCREASE THE COVERAGE
OF SLIGHT CHANCE POPS IF DEVELOPMENT BECOMES MORE ACTIVE LATER
TODAY. ELSEWHERE...STORMS CHANCES ARE LOWER THAN YESTERDAY WITH
DECREASING MOISTURE. PRECIPITABLE WATER VALUES DROP TO AROUND 1 INCH
OR EVEN SLIGHTLY BELOW AN INCH ACROSS EASTERN ARIZONA...SO NOT
EXPECTING ACTIVE STORM DEVELOPMENT ACROSS THE HIGHER TERRAIN EAST OF
PHOENIX. ANY SHOWERS OR THUNDERSTORMS THAT DO DEVELOP WILL LIKELY BE
LIMITED AND STAY WELL EAST OF THE VALLEY.
&&
.PREVIOUS DISCUSSION...
LATEST WV IMAGERY SHOWS A COMPACT VORT MAX MOVING STEADILY WESTWARD
ACROSS NORTHERN SONORA WHILE ISOLATED THUNDERSTORMS HAVE PERSISTED
EARLY THIS MORNING ACROSS PIMA COUNTY. MODELS HAVE HAD A DIFFICULT
TIME INITIALIZING THE TROUGH...THOUGH THE LATEST HRRR SUGGESTS
ISOLATED CONVECTION WILL REMAIN A THREAT THROUGH THE DAY FROM YUMA
INTO THE IMPERIAL VALLEY. A WEAK BOUNDARY IS EVIDENT ON IR SATELLITE
AND IT SEEMS REASONABLE THAT ISOLATED CELLS COULD DEVELOP ALONG AND
AHEAD OF THIS FEATURE. FURTHER EAST ACROSS SOUTH-CENTRAL
AZ...EXCESSIVE HEAT WILL BE THE MAIN STORY AS A STRONG ANTICYCLONE
IN NM DRIFTS WESTWARD AND INTO NORTHERN AZ BY THIS AFTERNOON.
INCREASING NVA AND WEAK SUBSIDENCE WILL GENERALLY PRECLUDE
CONVECTION ACROSS THE LOWER DESERTS. STEERING FLOW REMAINS WEAK AND
ISOLATED THUNDERSTORMS ARE AGAIN EXPECTED TO REMAIN CONFINED TO THE
HIGHER ELEVATIONS OF GILA COUNTY. TEMPERATURES WERE WEIGHTED HEAVILY
TOWARDS THE ECMWF...WHICH HAS PERFORMED WELL RECENTLY AND TENDS TO
DO A BETTER JOB WITH EXCESSIVE HEAT EVENTS. RECORD HIGH TEMPERATURE
FOR TODAY IN PHOENIX IS 112 DEGREES...SET IN 1905...AND IS IN
JEOPARDY OF BEING TIED OR EVEN BROKEN THIS AFTERNOON.
CENTER OF THE ANTICYCLONE WILL MOVE INTO UT WEDNESDAY. THIS WILL
PRODUCE A WEAK NORTHEASTERLY FLOW WHICH WILL INCREASE DOWNSLOPING
AND ADIABATIC WARMING. TEMPERATURES ARE EXPECTED TO BE 1 TO 3
DEGREES WARMER THAN THOSE TUESDAY AND THE RECORD HIGH TEMPERATURE OF
113 DEGREES IN PHOENIX IS AGAIN IN JEOPARDY OF BEING ECLIPSED.
TEMPERATURES WILL BE EVEN WARMER ACROSS SW AZ AND SE CA AND THE
EXCESSIVE HEAT WATCH HAS BEEN UPGRADED TO A WARNING IN THESE AREAS.
LATEST SREF SHOWS DEEPER MOISTURE CURRENTLY ACROSS THE SOUTHERN
ROCKIES WHICH IS EXPECTED TO REACH EASTERN AZ WED EVENING. SCATTERED
THUNDERSTORMS WILL HAVE THE POTENTIAL TO PROPAGATE OUT OF GILA
COUNTY AND INTO THE LOWER ELEVATIONS WEDNESDAY NIGHT. AT THE VERY
LEAST...BLOWING DUST WILL BE A THREAT ACROSS THE PHOENIX METRO AREA
AND INTO PINAL COUNTY.
EASTERLY FLOW WILL STRENGTHEN THURSDAY AS THE HIGH BECOMES
POSITIONED NEAR THE FOUR CORNERS. DRIER AIR WILL SHIFT WESTWARD AND
THERE IS INCREASING UNCERTAINTY WITH REGARD TO THE EXCESSIVE HEAT.
IT IS CONCEIVABLE THAT THURSDAY WILL BE COOLER IF AN OUTFLOW
BOUNDARY MOVES THROUGH WEDNESDAY NIGHT. AT THIS POINT...THE WATCH
WILL BE EXTENDED ONLY FOR SW AZ AND SE CA.
THE ANOMALOUS HIGH WILL PERSIST INTO EARLY NEXT WEEK. GFS/ECMWF IN
GOOD AGREEMENT THAT DRIER AIR WILL EVENTUALLY BE ADVECTED WESTWARD.
ANOTHER STRETCH OF EXCESSIVE HEAT IS LIKELY ALONG WITH BELOW AVERAGE
RAIN CHANCES.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
FEW-SCT MID-HIGH LEVEL CLOUDS...ALONG WITH WINDS AROUND 10KT OR LESS
TO PREVAIL INTO WEDNESDAY MORNING. AFTN/EVE THUNDERSTORM ACTIVITY
WILL BE ISOLATED AT BEST...MAINLY CONFINED TO THE MOGOLLON RIM...
WHITE MOUNTAINS...SOUTHEAST ARIZONA.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
WEAK DISTURBANCE COULD BRING INCREASING MID LEVEL CLOUD DECKS OVER
THE AREA THIS MORNING ALONG WITH AN ISOLATED THUNDERSTORM...HOWEVER
CONFIDENCE TOO LOW TO MENTION CONVECTION IN TAFS AT THIS TIME.
OTHERWISE...MOSTLY SUNNY/CLEAR SKIES AND LIGHT WINDS EXPECTED THIS
AFTERNOON INTO WEDNESDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG UPPER LEVEL HIGH PRESSURE WILL REMAIN OVER THE REGION INTO
THE WEEKEND. AS A RESULT...ABOVE NORMAL/VERY HOT TEMPERATURES AND
DAYTIME RELATIVE HUMIDITY VALUES IN THE TEENS ARE EXPECTED THROUGH
THE PERIOD. SUFFICIENT MOISTURE AND INSTABILITY OVER THE MOUNTAINS
OF SOUTH-CENTRAL ARIZONA WILL PROVIDE A DAILY THREAT OF AFTERNOON
AND EVENING THUNDERSTORMS...AND OCCASIONALLY A FEW STORMS COULD
PROPAGATE INTO THE LOWER DESERT ELEVATIONS. ANY WETTING RAINFALL
EVENTS WILL BE ISOLATED AND SPORADIC. OUTSIDE OF STRONG GUSTY WINDS
ASSOCIATED WITH STORMS...LIGHT WINDS EXPECTED THROUGH THE PERIOD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING UNTIL 8 PM MST WEDNESDAY
AZZ022-023-027-028.
EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM MST WEDNESDAY
AZZ020-021-025-026.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM PDT WEDNESDAY
CAZ031>033.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING CAZ031>033.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN
PREVIOUS DISCUSSION...HIRSCH
AVIATION...MEYERS
FIRE WEATHER...MO/MEYERS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
513 AM MST TUE AUG 7 2012
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL OVER THE DESERT SOUTHWEST THIS
WEEK...RESULTING IN WELL ABOVE NORMAL TEMPERATURES AND PERIODS OF
EXCESSIVE HEAT. THUNDERSTORM CHANCES WILL BE FOCUSED MAINLY OVER
HIGHER TERRAIN OF NORTHERN AND EASTERN ARIZONA TODAY...THOUGH THERE
WILL BE A CHANCE OF STORMS WEDNESDAY AND THURSDAY ACROSS
SOUTH-CENTRAL ARIZONA. THE WELL ABOVE NORMAL TEMPERATURES WILL
PERSIST THROUGH AT LEAST THE WEEKEND ALONG WITH BELOW NORMAL CHANCES
FOR RAIN AND THUNDERSTORMS.
&&
.DISCUSSION...
LATEST WV IMAGERY SHOWS A COMPACT VORT MAX MOVING STEADILY WESTWARD
ACROSS NORTHERN SONORA WHILE ISOLATED THUNDERSTORMS HAVE PERSISTED
EARLY THIS MORNING ACROSS PIMA COUNTY. MODELS HAVE HAD A DIFFICULT
TIME INITIALIZING THE TROUGH...THOUGH THE LATEST HRRR SUGGESTS
ISOLATED CONVECTION WILL REMAIN A THREAT THROUGH THE DAY FROM YUMA
INTO THE IMPERIAL VALLEY. A WEAK BOUNDARY IS EVIDENT ON IR SATELLITE
AND IT SEEMS REASONABLE THAT ISOLATED CELLS COULD DEVELOP ALONG AND
AHEAD OF THIS FEATURE. FURTHER EAST ACROSS SOUTH-CENTRAL
AZ...EXCESSIVE HEAT WILL BE THE MAIN STORY AS A STRONG ANTICYCLONE
IN NM DRIFTS WESTWARD AND INTO NORTHERN AZ BY THIS AFTERNOON.
INCREASING NVA AND WEAK SUBSIDENCE WILL GENERALLY PRECLUDE
CONVECTION ACROSS THE LOWER DESERTS. STEERING FLOW REMAINS WEAK AND
ISOLATED THUNDERSTORMS ARE AGAIN EXPECTED TO REMAIN CONFINED TO THE
HIGHER ELEVATIONS OF GILA COUNTY. TEMPERATURES WERE WEIGHTED HEAVILY
TOWARDS THE ECMWF...WHICH HAS PERFORMED WELL RECENTLY AND TENDS TO
DO A BETTER JOB WITH EXCESSIVE HEAT EVENTS. RECORD HIGH TEMPERATURE
FOR TODAY IN PHOENIX IS 112 DEGREES...SET IN 1905...AND IS IN
JEOPARDY OF BEING TIED OR EVEN BROKEN THIS AFTERNOON.
CENTER OF THE ANTICYCLONE WILL MOVE INTO UT WEDNESDAY. THIS WILL
PRODUCE A WEAK NORTHEASTERLY FLOW WHICH WILL INCREASE DOWNSLOPING
AND ADIABATIC WARMING. TEMPERATURES ARE EXPECTED TO BE 1 TO 3
DEGREES WARMER THAN THOSE TUESDAY AND THE RECORD HIGH TEMPERATURE OF
113 DEGREES IN PHOENIX IS AGAIN IN JEOPARDY OF BEING ECLIPSED.
TEMPERATURES WILL BE EVEN WARMER ACROSS SW AZ AND SE CA AND THE
EXCESSIVE HEAT WATCH HAS BEEN UPGRADED TO A WARNING IN THESE AREAS.
LATEST SREF SHOWS DEEPER MOISTURE CURRENTLY ACROSS THE SOUTHERN
ROCKIES WHICH IS EXPECTED TO REACH EASTERN AZ WED EVENING. SCATTERED
THUNDERSTORMS WILL HAVE THE POTENTIAL TO PROPAGATE OUT OF GILA
COUNTY AND INTO THE LOWER ELEVATIONS WEDNESDAY NIGHT. AT THE VERY
LEAST...BLOWING DUST WILL BE A THREAT ACROSS THE PHOENIX METRO AREA
AND INTO PINAL COUNTY.
EASTERLY FLOW WILL STRENGTHEN THURSDAY AS THE HIGH BECOMES
POSITIONED NEAR THE FOUR CORNERS. DRIER AIR WILL SHIFT WESTWARD AND
THERE IS INCREASING UNCERTAINTY WITH REGARD TO THE EXCESSIVE HEAT.
IT IS CONCEIVABLE THAT THURSDAY WILL BE COOLER IF AN OUTFLOW
BOUNDARY MOVES THROUGH WEDNESDAY NIGHT. AT THIS POINT...THE WATCH
WILL BE EXTENDED ONLY FOR SW AZ AND SE CA.
THE ANOMALOUS HIGH WILL PERSIST INTO EARLY NEXT WEEK. GFS/ECMWF IN
GOOD AGREEMENT THAT DRIER AIR WILL EVENTUALLY BE ADVECTED WESTWARD.
ANOTHER STRETCH OF EXCESSIVE HEAT IS LIKELY ALONG WITH BELOW AVERAGE
RAIN CHANCES.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
FEW-SCT MID-HIGH LEVEL CLOUDS...ALONG WITH WINDS AROUND 10KT OR LESS
TO PREVAIL INTO WEDNESDAY MORNING. AFTN/EVE THUNDERSTORM ACTIVITY
WILL BE ISOLATED AT BEST...MAINLY CONFINED TO THE MOGOLLON RIM...
WHITE MOUNTAINS...SOUTHEAST ARIZONA.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
WEAK DISTURBANCE COULD BRING INCREASING MID LEVEL CLOUD DECKS OVER
THE AREA THIS MORNING ALONG WITH AN ISOLATED THUNDERSTORM...HOWEVER
CONFIDENCE TOO LOW TO MENTION CONVECTION IN TAFS AT THIS TIME.
OTHERWISE...MOSTLY SUNNY/CLEAR SKIES AND LIGHT WINDS EXPECTED THIS
AFTERNOON INTO WEDNESDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG UPPER LEVEL HIGH PRESSURE WILL REMAIN OVER THE REGION INTO
THE WEEKEND. AS A RESULT...ABOVE NORMAL/VERY HOT TEMPERATURES AND
DAYTIME RELATIVE HUMIDITY VALUES IN THE TEENS ARE EXPECTED THROUGH
THE PERIOD. SUFFICIENT MOISTURE AND INSTABILITY OVER THE MOUNTAINS
OF SOUTH-CENTRAL ARIZONA WILL PROVIDE A DAILY THREAT OF AFTERNOON
AND EVENING THUNDERSTORMS...AND OCCASIONALLY A FEW STORMS COULD
PROPAGATE INTO THE LOWER DESERT ELEVATIONS. ANY WETTING RAINFALL
EVENTS WILL BE ISOLATED AND SPORADIC. OUTSIDE OF STRONG GUSTY WINDS
ASSOCIATED WITH STORMS...LIGHT WINDS EXPECTED THROUGH THE PERIOD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING UNTIL 8 PM MST WEDNESDAY
AZZ022-023-027-028.
EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM MST WEDNESDAY
AZZ020-021-025-026.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM PDT WEDNESDAY
CAZ031>033.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING CAZ031>033.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...MEYERS
FIRE WEATHER...MO/MEYERS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
350 AM MST TUE AUG 7 2012
.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL OVER THE DESERT SOUTHWEST THIS
WEEK...RESULTING IN WELL ABOVE NORMAL TEMPERATURES AND PERIODS OF
EXCESSIVE HEAT. THUNDERSTORM CHANCES WILL BE FOCUSED MAINLY OVER
HIGHER TERRAIN OF NORTHERN AND EASTERN ARIZONA TODAY...THOUGH THERE
WILL BE A CHANCE OF STORMS WEDNESDAY AND THURSDAY ACROSS
SOUTH-CENTRAL ARIZONA. THE WELL ABOVE NORMAL TEMPERATURES WILL
PERSIST THROUGH AT LEAST THE WEEKEND ALONG WITH BELOW NORMAL CHANCES
FOR RAIN AND THUNDERSTORMS.
&&
.DISCUSSION...
LATEST WV IMAGERY SHOWS A COMPACT VORT MAX MOVING STEADILY WESTWARD
ACROSS NORTHERN SONORA WHILE ISOLATED THUNDERSTORMS HAVE PERSISTED
EARLY THIS MORNING ACROSS PIMA COUNTY. MODELS HAVE HAD A DIFFICULT
TIME INITIALIZING THE TROUGH...THOUGH THE LATEST HRRR SUGGESTS
ISOLATED CONVECTION WILL REMAIN A THREAT THROUGH THE DAY FROM YUMA
INTO THE IMPERIAL VALLEY. A WEAK BOUNDARY IS EVIDENT ON IR SATELLITE
AND IT SEEMS REASONABLE THAT ISOLATED CELLS COULD DEVELOP ALONG AND
AHEAD OF THIS FEATURE. FURTHER EAST ACROSS SOUTH-CENTRAL
AZ...EXCESSIVE HEAT WILL BE THE MAIN STORY AS A STRONG ANTICYCLONE
IN NM DRIFTS WESTWARD AND INTO NORTHERN AZ BY THIS AFTERNOON.
INCREASING NVA AND WEAK SUBSIDENCE WILL GENERALLY PRECLUDE
CONVECTION ACROSS THE LOWER DESERTS. STEERING FLOW REMAINS WEAK AND
ISOLATED THUNDERSTORMS ARE AGAIN EXPECTED TO REMAIN CONFINED TO THE
HIGHER ELEVATIONS OF GILA COUNTY. TEMPERATURES WERE WEIGHTED HEAVILY
TOWARDS THE ECMWF...WHICH HAS PERFORMED WELL RECENTLY AND TENDS TO
DO A BETTER JOB WITH EXCESSIVE HEAT EVENTS. RECORD HIGH TEMPERATURE
FOR TODAY IN PHOENIX IS 112 DEGREES...SET IN 1905...AND IS IN
JEOPARDY OF BEING TIED OR EVEN BROKEN THIS AFTERNOON.
CENTER OF THE ANTICYCLONE WILL MOVE INTO UT WEDNESDAY. THIS WILL
PRODUCE A WEAK NORTHEASTERLY FLOW WHICH WILL INCREASE DOWNSLOPING
AND ADIABATIC WARMING. TEMPERATURES ARE EXPECTED TO BE 1 TO 3
DEGREES WARMER THAN THOSE TUESDAY AND THE RECORD HIGH TEMPERATURE OF
113 DEGREES IN PHOENIX IS AGAIN IN JEOPARDY OF BEING ECLIPSED.
TEMPERATURES WILL BE EVEN WARMER ACROSS SW AZ AND SE CA AND THE
EXCESSIVE HEAT WATCH HAS BEEN UPGRADED TO A WARNING IN THESE AREAS.
LATEST SREF SHOWS DEEPER MOISTURE CURRENTLY ACROSS THE SOUTHERN
ROCKIES WHICH IS EXPECTED TO REACH EASTERN AZ WED EVENING. SCATTERED
THUNDERSTORMS WILL HAVE THE POTENTIAL TO PROPAGATE OUT OF GILA
COUNTY AND INTO THE LOWER ELEVATIONS WEDNESDAY NIGHT. AT THE VERY
LEAST...BLOWING DUST WILL BE A THREAT ACROSS THE PHOENIX METRO AREA
AND INTO PINAL COUNTY.
EASTERLY FLOW WILL STRENGTHEN THURSDAY AS THE HIGH BECOMES
POSITIONED NEAR THE FOUR CORNERS. DRIER AIR WILL SHIFT WESTWARD AND
THERE IS INCREASING UNCERTAINTY WITH REGARD TO THE EXCESSIVE HEAT.
IT IS CONCEIVABLE THAT THURSDAY WILL BE COOLER IF AN OUTFLOW
BOUNDARY MOVES THROUGH WEDNESDAY NIGHT. AT THIS POINT...THE WATCH
WILL BE EXTENDED ONLY FOR SW AZ AND SE CA.
THE ANOMALOUS HIGH WILL PERSIST INTO EARLY NEXT WEEK. GFS/ECMWF IN
GOOD AGREEMENT THAT DRIER AIR WILL EVENTUALLY BE ADVECTED WESTWARD.
ANOTHER STRETCH OF EXCESSIVE HEAT IS LIKELY ALONG WITH BELOW AVERAGE
RAIN CHANCES.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
FEW-SCT MID-HIGH LEVEL CIGS ARE EXPECTED TO PREVAIL AT THE PHOENIX
AREA TERMINALS THRU THE TAF PERIOD. GUSTY NORTHEASTERLY WINDS THAT
WERE SEEN AT THE TERMINALS A COUPLE OF HOURS AGO HAVE DIMINISHED.
TYPICAL EASTERLY DIURNAL WINDS ARE EXPECTED TO PREVAIL THRU THE REST
OF TONIGHT...ALTHOUGH THEY BE ENHANCED A BIT OVER THE NEXT FEW HOURS
BY OUTFLOWS FROM DISSIPATING THUNDERSTORMS OVER SOUTHEAST PINAL
COUNTY.
SOUTHEAST CALIFORNIA...SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
VFR CIRRUS CIGS AND MAINLY LIGHT WINDS TO PREVAIL AT BOTH KBLH AND
KIPL THROUGH THE PERIOD.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG UPPER LEVEL HIGH PRESSURE WILL REMAIN STATIONED OVER THE
INTERMOUNTAIN WEST THROUGH THE WEEKEND. AS A RESULT...ABOVE
NORMAL/VERY HOT TEMPERATURES AND DAILY DAYTIME RELATIVE HUMIDITY
VALUES IN THE TEENS ARE EXPECTED. SUFFICIENT MOISTURE AND
INSTABILITY OVER THE MOUNTAINS OF SOUTH-CENTRAL ARIZONA WILL PROVIDE
NEARLY A DAILY THREAT OF AFTERNOON/EVENING THUNDERSTORMS...AND
OCCASIONALLY A FEW STORMS COULD PROPAGATE INTO THE LOWER DESERT
ELEVATIONS. ANY WETTING RAINFALL EVENTS WILL BE ISOLATED AND
SPORADIC. OUTSIDE OF ANY STRONG GUSTY WINDS ASSOCIATED WITH
STORMS...LIGHT WINDS EXPECTED THROUGH THE PERIOD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING UNTIL 8 PM MST WEDNESDAY
AZZ022-023-027-028.
EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM MST WEDNESDAY
AZZ020-021-025-026.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM PDT WEDNESDAY
CAZ031>033.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING CAZ031>033.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...PERCHA
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
350 PM MST TUE AUG 7 2012
.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL OVER THE DESERT SOUTHWEST THIS
WEEK...RESULTING IN WELL ABOVE NORMAL TEMPERATURES AND PERIODS OF
EXCESSIVE HEAT. THUNDERSTORM CHANCES WILL BE FOCUSED MAINLY OVER
HIGHER TERRAIN OF NORTHERN AND EASTERN ARIZONA TODAY...THOUGH THERE
WILL BE A CHANCE OF STORMS WEDNESDAY AND THURSDAY ACROSS
SOUTH-CENTRAL ARIZONA. THE WELL ABOVE NORMAL TEMPERATURES WILL
PERSIST THROUGH AT LEAST THE WEEKEND ALONG WITH BELOW NORMAL CHANCES
FOR RAIN AND THUNDERSTORMS.
&&
.DISCUSSION...
LATEST WV IMAGERY SHOWS A COMPACT VORT MAX MOVING STEADILY WESTWARD
ACROSS NORTHERN SONORA WHILE ISOLATED THUNDERSTORMS HAVE PERSISTED
EARLY THIS MORNING ACROSS PIMA COUNTY. MODELS HAVE HAD A DIFFICULT
TIME INITIALIZING THE TROUGH...THOUGH THE LATEST HRRR SUGGESTS
ISOLATED CONVECTION WILL REMAIN A THREAT THROUGH THE DAY FROM YUMA
INTO THE IMPERIAL VALLEY. A WEAK BOUNDARY IS EVIDENT ON IR SATELLITE
AND IT SEEMS REASONABLE THAT ISOLATED CELLS COULD DEVELOP ALONG AND
AHEAD OF THIS FEATURE. FURTHER EAST ACROSS SOUTH-CENTRAL
AZ...EXCESSIVE HEAT WILL BE THE MAIN STORY AS A STRONG ANTICYCLONE
IN NM DRIFTS WESTWARD AND INTO NORTHERN AZ BY THIS AFTERNOON.
INCREASING NVA AND WEAK SUBSIDENCE WILL GENERALLY PRECLUDE
CONVECTION ACROSS THE LOWER DESERTS. STEERING FLOW REMAINS WEAK AND
ISOLATED THUNDERSTORMS ARE AGAIN EXPECTED TO REMAIN CONFINED TO THE
HIGHER ELEVATIONS OF GILA COUNTY. TEMPERATURES WERE WEIGHTED HEAVILY
TOWARDS THE ECMWF...WHICH HAS PERFORMED WELL RECENTLY AND TENDS TO
DO A BETTER JOB WITH EXCESSIVE HEAT EVENTS. RECORD HIGH TEMPERATURE
FOR TODAY IN PHOENIX IS 112 DEGREES...SET IN 1905...AND IS IN
JEOPARDY OF BEING TIED OR EVEN BROKEN THIS AFTERNOON.
CENTER OF THE ANTICYCLONE WILL MOVE INTO UT WEDNESDAY. THIS WILL
PRODUCE A WEAK NORTHEASTERLY FLOW WHICH WILL INCREASE DOWNSLOPING
AND ADIABATIC WARMING. TEMPERATURES ARE EXPECTED TO BE 1 TO 3
DEGREES WARMER THAN THOSE TUESDAY AND THE RECORD HIGH TEMPERATURE OF
113 DEGREES IN PHOENIX IS AGAIN IN JEOPARDY OF BEING ECLIPSED.
TEMPERATURES WILL BE EVEN WARMER ACROSS SW AZ AND SE CA AND THE
EXCESSIVE HEAT WATCH HAS BEEN UPGRADED TO A WARNING IN THESE AREAS.
LATEST SREF SHOWS DEEPER MOISTURE CURRENTLY ACROSS THE SOUTHERN
ROCKIES WHICH IS EXPECTED TO REACH EASTERN AZ WED EVENING. SCATTERED
THUNDERSTORMS WILL HAVE THE POTENTIAL TO PROPAGATE OUT OF GILA
COUNTY AND INTO THE LOWER ELEVATIONS WEDNESDAY NIGHT. AT THE VERY
LEAST...BLOWING DUST WILL BE A THREAT ACROSS THE PHOENIX METRO AREA
AND INTO PINAL COUNTY.
EASTERLY FLOW WILL STRENGTHEN THURSDAY AS THE HIGH BECOMES
POSITIONED NEAR THE FOUR CORNERS. DRIER AIR WILL SHIFT WESTWARD AND
THERE IS INCREASING UNCERTAINTY WITH REGARD TO THE EXCESSIVE HEAT.
IT IS CONCEIVABLE THAT THURSDAY WILL BE COOLER IF AN OUTFLOW
BOUNDARY MOVES THROUGH WEDNESDAY NIGHT. AT THIS POINT...THE WATCH
WILL BE EXTENDED ONLY FOR SW AZ AND SE CA.
THE ANOMALOUS HIGH WILL PERSIST INTO EARLY NEXT WEEK. GFS/ECMWF IN
GOOD AGREEMENT THAT DRIER AIR WILL EVENTUALLY BE ADVECTED WESTWARD.
ANOTHER STRETCH OF EXCESSIVE HEAT IS LIKELY ALONG WITH BELOW AVERAGE
RAIN CHANCES.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
FEW-SCT MID-HIGH LEVEL CIGS ARE EXPECTED TO PREVAIL AT THE PHOENIX
AREA TERMINALS THRU THE TAF PERIOD. GUSTY NORTHEASTERLY WINDS THAT
WERE SEEN AT THE TERMINALS A COUPLE OF HOURS AGO HAVE DIMINISHED.
TYPICAL EASTERLY DIURNAL WINDS ARE EXPECTED TO PREVAIL THRU THE REST
OF TONIGHT...ALTHOUGH THEY BE ENHANCED A BIT OVER THE NEXT FEW HOURS
BY OUTFLOWS FROM DISSIPATING THUNDERSTORMS OVER SOUTHEAST PINAL
COUNTY.
SOUTHEAST CALIFORNIA...SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
VFR CIRRUS CIGS AND MAINLY LIGHT WINDS TO PREVAIL AT BOTH KBLH AND
KIPL THROUGH THE PERIOD.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG UPPER LEVEL HIGH PRESSURE WILL REMAIN STATIONED OVER THE
INTERMOUNTAIN WEST THROUGH THE WEEKEND. AS A RESULT...ABOVE
NORMAL/VERY HOT TEMPERATURES AND DAILY DAYTIME RELATIVE HUMIDITY
VALUES IN THE TEENS ARE EXPECTED. SUFFICIENT MOISTURE AND
INSTABILITY OVER THE MOUNTAINS OF SOUTH-CENTRAL ARIZONA WILL PROVIDE
NEARLY A DAILY THREAT OF AFTERNOON/EVENING THUNDERSTORMS...AND
OCCASIONALLY A FEW STORMS COULD PROPAGATE INTO THE LOWER DESERT
ELEVATIONS. ANY WETTING RAINFALL EVENTS WILL BE ISOLATED AND
SPORADIC. OUTSIDE OF ANY STRONG GUSTY WINDS ASSOCIATED WITH
STORMS...LIGHT WINDS EXPECTED THROUGH THE PERIOD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING UNTIL 8 PM MST WEDNESDAY
AZZ022-023-027-028.
EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM MST WEDNESDAY
AZZ020-021-025-026.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM TO 8 PM PDT WEDNESDAY
CAZ031>033.
EXCESSIVE HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY
EVENING CAZ031>033.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...PERCHA
FIRE WEATHER...MO
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
140 AM EDT TUE AUG 7 2012
.PREV DISCUSSION... /ISSUED 1014 PM EDT MON AUG 6 2012/
UPDATE...
MAIN AREA OF PERSISTENT CONVECTIVE DEVELOPMENT PAST DIURNAL
HEATING HAS BEEN ACROSS THE NORTHERN PORTION OF THE AREA ALONG AN
AXIS OF SFC CONVERGENCE. AS WEAK UPPER LOW CONTINUES TO BE
CENTERED NEAR SW GA...A MOIST TROPICAL AIRMASS REMAINS IN PLACE
WITH PWATS OF 2 INCHES OR GREATER. ANY REMNANT BOUNDARY OR WEAK
FORCING FOR ASCENT WILL MAINTAIN AT LEAST SHOWER POTENTIAL THROUGH
THE OVERNIGHT. WITH THE LATEST HRRR SOLUTION SUPPORTING CONTINUED
ACTIVITY IN THE NORTH INTO THE EARLY MORNING...HAVE INCLUDED
LIKELY POPS ACROSS THE NORTH UNTIL 06Z AND CHANCE POPS ELSEWHERE
CONTINUING INTO TUESDAY. PRIMARILY SHOWERS POSSIBLE WITH ISOLATED
THUNDER. MADE ONLY MINOR TREND TWEAKS TO TEMPS AND DEWPOINTS.
PREVIOUS DISCUSSION FOLLOWS...
03
PREV DISCUSSION... /ISSUED 225 PM EDT MON AUG 6 2012/
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
WEAK TROPICAL LOW HAS WORKED ITS WAY INTO SOUTHEAST ALABAMA THIS
AFTERNOON AND IS PROGGED TO REMAIN IN THAT VICINITY THROUGH TONIGHT.
INDICATIONS ARE THE LOW WILL BEGIN LIFTING NORTHEAST ACROSS THE
FORECAST AREA BY TUESDAY AFTERNOON AND TUESDAY NIGHT. AS LONG AS THE
LOW REMAINS ACROSS THE SOUTHERN PORTIONS OF ALABAMA AND GEORGIA THE
WEAK COLD FRONT EXTENDING FROM THE MID-ATLANTIC COASTAL REGION TO
THE SOUTHERN PLAINS SHOULD BE HELD AT BAY. INSTABILITY REMAINS
MARGINAL THROUGH THE PERIOD AS THE VERTICAL TEMPERATURE PROFILES
REMAIN NEARLY MOIST ADIABATIC. BIGGEST THREAT FROM ANY CONVECTION IS
LIKELY TO BE LOCALLY HEAVY RAIN AS PRECIPITABLE WATER VALUES
CONTINUE TO HOVER AROUND THE 2 INCH RANGE. HARD TO TIME WHEN THE
BEST CHANCES FOR PRECIPITATION WILL BE THROUGH THE PERIOD AS
NORTHWEST UPPER FLOW IS LIKELY TO TRANSPORT A SERIES OF WEAK WAVES
INTO THE AREA. IN GENERAL I HAVE STUCK WITH A DIURNAL MAXIMUM
PATTERN TO THE PROBABILITY OF PRECIPITATION. EXTENSIVE CLOUD COVER
AND WIDESPREAD PRECIPITATION WILL KEEP TEMPERATURES AT OR BELOW
SEASONAL NORMALS THROUGH THE PERIOD.
20
LONG TERM /WEDNESDAY THROUGH MONDAY/...
TROPICAL MOISTURE REMAINS OVER THE REGION WEDNESDAY HOWEVER THE
WESTERLIES DIP DOWN A LITTLE INTO NORTH GA AND TRIES TO PUSH A WEAK
SURFACE TROUGH INTO THE NORTHERN PART OF THE CWA. THIS WILL AID IN
SHOWERS/THUNDERSTORMS...MAINLY DURING THE AFTERNOON WEDNESDAY ACROSS
THE CWA. NO OTHER CHANGES ARE PLANNED FOR THE REST OF THE LONG TERM.
PREVIOUS LONG TERM DISCUSSION FOLLOWS...
PREV LONG TERM DISCUSSION... /ISSUED 337 AM EDT MON AUG 6 2012/
/WEDNESDAY THROUGH SUNDAY/... OVERALL PATTERN REMAINS THE SAME
WITH BOTH GFS AND ECMWF IN GENERAL AGREEMENT. THE FORECAST AREA
PERSISTS IN A BROAD EASTERN TROUGH WITH A STALLED SURFACE BOUNDARY
WITH WEAK WAVES TRAVELING ALONG IT. WITH ABUNDANT TROPICAL
MOISTURE AVAILABLE...HAVE KEPT THE POPS IN AN AVERAGE 40 TO 50
PERCENT RANGE UNTIL THE END OF THE WEEK. MODELS STILL SHOWING SOME
DRYING AS AN UPPER CLOSED LOW DEEPENS OVER THE GREAT LAKES. THIS
MAY PUSH THE SURFACE BOUNDARY INTO SOUTH GEORGIA BEGINNING ON
SATURDAY. SO HAVE REDUCED THE POPS A BIT FOR SATURDAY AND SUNDAY.
WITH POTENTIAL FOR INCREASED CLOUD COVER...HIGHS IN THE MID 80S TO
LOW 90S LOOK REASONABLE FOR MUCH OF THE AREA.
17/41
&&
.AVIATION...
06Z UPDATE...
VFR CIGS ACROSS THE AREA WILL LOW TO MVFR AND THEN IFR BY BETWEEN
10-12Z. MVFR AND BRIEFLY LOWER VSBYS EXPECTED...THOUGH TAF WILL
ONLY CARRY MVFR. SHRA AROUND OFF AND ON THROUGH MOST OF THE DAY
WITH THE POSSIBILITY OF TSRA THIS AFTERNOON...HAVE CONTINUED
PROB30 FOR TSRA. EASTERLY WINDS WILL SHIFT MORE SSE LATER THIS
MORNING...BACK TO EAST THIS EVENING. SOME GUIDANCE SUGGESTING
BRIEF SSW WINDS BETWEEN 14-18Z BUT HAVE KEPT THEM ON THE EAST SIDE.
EXPECT ANOTHER ROUND OF MVFR TO IFR CIGS AGAIN WEDNESDAY MORNING.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON MOST ELEMENTS.
LOW ON POTENTIAL FOR WINDS TO SHIFT SSW MIDDAY.
LOW ON POTENTIAL FOR TSRA IMPACTS AT ATL.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 86 70 87 71 / 60 50 60 40
ATLANTA 86 73 87 73 / 60 50 60 40
BLAIRSVILLE 82 66 83 64 / 70 50 40 40
CARTERSVILLE 86 68 89 69 / 60 50 50 40
COLUMBUS 86 74 90 74 / 60 50 60 40
GAINESVILLE 86 71 86 71 / 60 50 60 40
MACON 86 73 88 73 / 60 50 60 40
ROME 86 69 91 70 / 60 50 40 40
PEACHTREE CITY 87 69 87 70 / 60 50 60 40
VIDALIA 87 74 88 75 / 70 50 60 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1139 PM CDT MON AUG 6 2012
.DISCUSSION...
ISSUED 858 PM CDT MON AUG 6 2012
CENTRAL ILLINOIS WILL BE ON THE WESTERN EDGES OF DEPARTING SURFACE
HIGH PRESSURE OVERNIGHT. THE RIDGE AXIS WILL STILL GENERALLY
RESIDE OVER OUR COUNTIES UNTIL LATE TONIGHT...PROVIDING LIGHT AND
VARIABLE WINDS UNDER MOSTLY CLEAR SKIES.
ONE ITEM OF NOTE FOR LATE TONIGHT FOR OUR WESTERN COUNTIES MAY BE
A STORM COMPLEX THAT IS PROJECTED TO DEVELOP IN SW MINNESOTA AND
NW IOWA...ALONG AN INVERTED TROUGH EXTENDING FROM LOW PRESSURE IN
WESTERN NEBRASKA. THE HRRR MODEL INDICATES THEY MAY MOVE EAST-
SOUTHEAST ACROSS IOWA TOWARD SUNRISE. WHILE THE STORMS SHOULD
REMAIN WEST-NW OF OUR AREA...SOME CIRRUS CLOUDS FROM THAT COMPLEX
MAY COVER OUR WESTERN COUNTIES...HELPING TO KEEP THEIR LOW TEMPS
SLIGHTLY WARMER THAN THE REST OF OUR CWA. OUR GRIDS ALREADY
REFLECTED THAT POSSIBILITY.
AS FOR WINDS...THE RIDGE AXIS WILL BEGIN TO SLIDE JUST EAST OF
ILLINOIS BY 12Z TUESDAY...WHICH MAY TRANSLATE INTO WINDS
DEVELOPING A SOUTHWEST DIRECTION BY SUNRISE IN OUR WESTERN
COUNTIES. THAT RETURN FLOW MAY CARRY SLIGHT WARM ADVECTION AS
WELL...WHICH WOULD ALSO WORK TO KEEP THE WESTERN COUNTIES SLIGHTLY
WARMER.
THE FORECAST GRIDS WERE GENERALLY IN GOOD SHAPE...WITH ONLY SOME
MINOR ADJUSTMENTS TO THE SKY GRIDS TO ACCOUNT FOR LATE NIGHT
CIRRUS IN THE WEST. NO FORMAL ZONE UPDATE WILL BE NEEDED FOR THE
SMALL CHANGES. UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
SHIMON
&&
.AVIATION...
ISSUED 1139 PM CDT MON AUG 6 2012...FOR THE 06Z TAFS
THE MAIN CONCERN WILL BE A WEAK TROUGH DROPPING INTO CENTRAL
ILLINOIS TOMORROW AFTERNOON. PIA/BMI WILL HAVE THE BEST CHANCES TO
SEE INCREASING MID CLOUDS AFTER 18Z. A FEW SHOWERS OR STORMS ARE
INDICATED IN THE QPF FIELDS OF THE MODELS...BUT THEY ARE GENERALLY
TOO AGGRESSIVE WITH PRECIP IN THESE MARGINAL CASES DURING A
DROUGHT. I WENT WITH A BROKEN CLOUD DECK AT PIA/BMI TMRW AFTN...IN
LIEU OF A VCSH.
WINDS MAY INCREASE TO AROUND 10KT FROM THE W-SW FOR PIA/BMI BY
MIDDAY...BUT WEAKER WINDS SHOULD PREVAIL FOR THE E-S TERMINALS.
NO REDUCTION TO VIS IS EXPECTED IN THE GENERALLY DRY AIRMASS.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 255 PM CDT MON AUG 6 2012
HIGH PRESSURE DOMINATING CENTRAL ILLINOIS WEATHER...AS WELL AS
MUCH OF THE MIDWEST THROUGHOUT THE FORECAST. UPPER RIDGING
CONTINUES OVER THE WESTERN HALF OF THE CONUS AND A FEW SYSTEMS
DIVE INTO THE GENERAL BROAD TROF OVER THE GREAT LAKES AND EASTERN
HALF OF THE COUNTRY. DEGREE OF INFLUENCE DEPENDING ON HOW DEEP THE
SYSTEMS DIG INTO THE TROF. SEEN THIS PATTERN SEVERAL TIMES OVER
THE SUMMER...WITH TEMPERATURES ON THE EDGE OF A MID LEVEL THERMAL
GRADIENT...A LITTLE MOVEMENT EITHER WAY OF THE WAVE PATTERN MAKES
A RATHER LARGE DIFFERENCE. THAT BEING SAID...STABILITY OF THE WAVE
PATTERN SEEMS TO BE IN AGREEMENT ACROSS OPERATIONAL MODELS.
HOWEVER...THE ISSUES COME INTO PLAY ON THE STRENGTH AND TIMING OF
THE WAVES FROM WED NIGHT INTO THU NIGHT...WITH THE NEXT CHANCE FOR
PRECIP.
SHORT TERM...TONIGHT AND TOMORROW...
QUIET WEATHER IN THE OVERNIGHT UNDER A RIDGE AXIS. CLEAR NIGHT AND
CALM WINDS EXPECTED. TOMORROW EXPECTED TO BE THE WARMEST OF THE
FORECAST...WITH LOW TO MID 90S ACROSS THE REGION AS THAT THERMAL
GRADIENT SLIPS A LITTLE FURTHER NORTH WITH THE WEAKER DIG INTO THE
EASTERN TROF. 19C TO 20C AT 850MB AND A RATHER DRY COLUMN WILL
KEEP THE TEMPS FAR ABOVE TODAY`S TEMPS. FLOW REMAINS RATHER
AMBIGUOUS THROUGH THE NEXT COUPLE OF DAYS WITH THE HIGH ANCHORING
THE WEATHER OVERALL.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
NEXT SYSTEM ON APPROACH WED NIGHT. FORECAST MODELS DIFFERING A BIT
WITH TIMING AND STRENGTH OF THE INITIAL WAVE FOR MIDWEST. GFS
EARLY AND WET...BRINGING IN QPF ON TUES NIGHT. HOWEVER...BOTH
ECMWF AND NAM ARE SLIGHTLY SLOWER AND MORE CONSERVATIVE WITH
INITIAL PRECIP...KEEPING BACK UNTIL WED NIGHT. THINK SOME
SPRINKLES MAY BE ABLE TO DEVELOP WITH AGGRESSIVE ENOUGH OF A CU
FIELD ON WEDNESDAY...AND HAVE ADDED THAT GRID...BUT WOULD LIKE TO
DEFER THE FORECAST TO THE MORE CONSERVATIVE SOLUTION CONSIDERING
THE ONGOING DROUGHT AND THE TREND OF THE SUMMER IN GENERAL. POPS
THURSDAY AND INTO THURS NIGHT. FRI SHOULD BE MOSTLY DRY...BUT SOME
AFTERNOON POP UPS WILL LIKELY REMAIN POSSIBLE ON THE EASTERN
BORDER OF THE STATE WITH THE EXITING SYSTEM UNLESS IT CONTINUES TO
ACCELERATE A BIT. REMAINING FORECAST IS DRY...AS GFS IS OVERDOING
THE EXTENDED A BIT...AND THE ECMWF KEEPS THE
MIDWEST...PARTICULARLY THE BULLSEYE IN THE MIDDLE OF CENTRAL
ILLINOIS...DRY.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1022 PM EDT WED AUG 8 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 246 PM EDT WED AUG 8 2012
A FRONTAL SYSTEM IS EXPECTED TO DROP SOUTH INTO THE AREA TONIGHT. A
WAVE OF LOW PRESSURE WILL MOVE ACROSS NORTHERN INDIANA DURING THE
DAY ON THURSDAY. THIS WILL DRAG A COLD FRONT THROUGH THE AREA
THURSDAY AFTERNOON AND NIGHT. IN THE WAKE OF THIS FRONT...HIGH
PRESSURE WILL BUILD INTO THE REGION. ANOTHER WEAK FRONTAL SYSTEM MAY
AFFECT THE AREA LATE IN THE WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 920 PM EDT WED AUG 8 2012
FOR THE REMAINDER OF THE NIGHT...WITH QUASISTATIONARY BOUNDARY IN
THE AREA...AND WEAK UPPER LEVEL WAVES...INCLUDING REMNANT MCV
MOVING THROUGH SRN GREAT LAKES...EXPECT SCATTERED THUNDERSTORMS.
COVERAGE HAS BEEN SLOW TO EXPAND THUS FAR THIS EVENING...ALTHOUGH
THERE IS SOME HINT IN SREF PROBABILITIES...RAP...AND HRRR THAT
EXPANSION OF COVERAGE MAY OCCUR WITH A SLIGHT INCREASE IN MID
LEVEL FLOW LATE TONIGHT. CONSIDERING THIS...HAVE DEPICTED 40 TO 50
POPS WITH SCATTERED WORDING THROUGHOUT...AND POPS HIGHEST IN
VICINITY OF THE BOUNDARY. ISOLATED STRONG STORM CANNOT BE RULED
OUT...AND 5 PERCENT/SEE TEXT ON DAY ONE OUTLOOK PERFECTLY REASONABLE.
INCREASED CLOUD COVER AND AS A RESULT...IN CONCERT WITH LATEST
HOURLY NUMERICAL GUIDANCE AND OBSERVATIONAL TRENDS...BUMPED MIN
TEMPS UP SLIGHTLY IN SOME PORTIONS OF THE AREA. STILL MID 60S TO
AROUND 70...JUST SOME MINOR TWEAKS TO INDIVIDUAL NUMBERS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 246 PM EDT WED AUG 8 2012
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES WILL AFFECT THE
FORECAST AREA DURING THIS PERIOD. ONE WAVE...CURRENTLY OVER THE
UPPER MISSISSIPPI VALLEY...IS EXPECTED TO MOVE THROUGH THURSDAY
AFTERNOON AND EVENING. THIS WILL BE FOLLOWED BY AN UPPER LOW WHICH
WILL SETTLE INTO THE GREAT LAKES BY FRIDAY AND SATURDAY.
A SURFACE LOW ASSOCIATED WITH THE FIRST UPPER WAVE IS EXPECTED TO
MOVE ACROSS NORTHERN INDIANA THURSDAY AFTERNOON...WHICH WILL DRAG A
COLD FRONT THROUGH THE FORECAST AREA LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. THIS SETUP LOOKS TO PROVIDE THE BEST CHANCES FOR
PRECIPITATION DURING THIS PERIOD. DEEP LAYER SHEAR IS INITIALLY
RATHER WEAK...BUT GETS PROGRESSIVELY STRONGER TOWARDS THE LATE
AFTERNOON AND EARLY EVENING HOURS ON THURSDAY. MID LEVEL LAPSE RATES
ARE MARGINALLY FAVORABLE FOR SEVERE STORMS...SO THERE IS SOME
POTENTIAL FOR STORM ORGANIZATION AND ATTENDANT THREAT FOR MAINLY
WIND DAMAGE GIVEN THE INCREASING DEEP SHEAR. WILL CONTINUE TO
MENTION POPS FOR THURSDAY AND THURSDAY NIGHT...WITH THE HIGHEST POPS
AROUND FRONTAL PASSAGE...FROM MID AFTERNOON THURSDAY UNTIL ABOUT
MIDNIGHT THURSDAY NIGHT.
WILL KEEP A SMALL POP IN THE FORECAST FOR FRIDAY WITH THE UPPER LOW
IN THE AREA. APPEARS BY SATURDAY...THE UPPER LOW WILL HAVE DRIFTED
FAR ENOUGH OFF TO THE NORTHEAST TO KEEP THAT PERIOD DRY.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR THURSDAY
ARE PROBABLY ABOUT 3-6 DEGREES TOO LOW. THE HIGHS ON FRIDAY LOOK
BETTER...BUT MAY STILL BE A LITTLE COOL. GUIDANCE LOWS LOOK OK AT
THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 246 PM EDT WED AUG 8 2012
MODELS HAVE LOW RAIN CHANCES AT TIMES...BUT CONSIDERING RECENT
BIASES A TOTALLY DRY FORECAST BEST BET.
EUROPEAN MOS AND MEX TEMPS CLOSE THROUGH PERIOD. FOR MINS...CONSALL
MODEL WE INITIALIZED WITH IS ALSO CLOSE AND SEE NO REASON TO
CHANGE.
EVERYTHING AGREES GRADUAL WARMING THROUGH THE PERIOD. GIVEN RECENT
BIASES IN WARMING SITUATIONS WILL GO A FEW DEGREES ABOVE EVEN
RELATIVELY HOT CONSALL.
&&
.AVIATION /DISCUSSION FOR 090300Z TAF UPDATES/...
ISSUED AT 1022 PM EDT WED AUG 8 2012
HAD TO ADJUST WINDS ESPECIALLY DIRECTIONS DUE TO SYNOPTIC AND
OUTFLOW BOUNDARIES IN THE AREA. OTHERWISE...KEPT TEMPO THUNDERSTORM
GROUPS GOING AT LAF AND BMG FOR THE NEXT FEW HOURS BASED ON RADAR
TRENDS...TOOK THEM OUT UNTIL 08Z AT IND AND 06Z AT HUF WHEN AN UPPER
TROUGH APPROACHES.
PREVIOUS DISCUSSION FOLLOWS...
EXPECT SOME THUNDERSTORMS ACROSS CENTRAL INDIANA TONIGHT AND
THURSDAY AS A QUASI-STATIONARY BOUNDARY COMBINES WITH UPPER WAVES
AND INSTABILITY. AWIPS DISTANCE AND SPEED TOOL SUGGESTS THUNDERSTORM
ACTIVITY WILL BE IN THE LAF AREA NEAR ISSUANCE TIME. WITH LIKELY
POPS THERE TONIGHT...WILL GO WITH PREVAILING -TSRA FOR THE FIRST TWO
HOURS OF THE TAF FOLLOWED BY 4 HOURS TEMPO -TSRA...AS RAPID REFRESH
SUGGESTS ADDITIONAL ACTIVITY WILL MOVE INTO THE AREA. NEXT BEST
CHANCE OF THUNDERSTORMS WILL BE AFTER 18Z TOMORROW AS AN UPPER WAVE
AND DEEPER MOISTURE APPROACHES. FOR THE OTHER SITES...NOT CONFIDENT
ENOUGH TO GO WITH ANYTHING MORE THAN VCTS TONIGHT WITH PROB30 GROUP
AFTER 18Z THURSDAY. CONDITIONS SHOULD BE VFR OUTSIDE OF
THUNDERSTORMS PER MODEL TIME SECTIONS MOISTURE PROFILE. WINDS WILL
BE LIGHT TO CALM TONIGHT BEFORE BECOMING SOUTHWEST AT LESS THAN 10
KNOTS THURSDAY AS THE FRONT LIFTS NORTH OF THE TERMINALS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...NIELD
SHORT TERM...JAS
LONG TERM....JK
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
921 PM EDT WED AUG 8 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 246 PM EDT WED AUG 8 2012
A FRONTAL SYSTEM IS EXPECTED TO DROP SOUTH INTO THE AREA TONIGHT. A
WAVE OF LOW PRESSURE WILL MOVE ACROSS NORTHERN INDIANA DURING THE
DAY ON THURSDAY. THIS WILL DRAG A COLD FRONT THROUGH THE AREA
THURSDAY AFTERNOON AND NIGHT. IN THE WAKE OF THIS FRONT...HIGH
PRESSURE WILL BUILD INTO THE REGION. ANOTHER WEAK FRONTAL SYSTEM MAY
AFFECT THE AREA LATE IN THE WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 920 PM EDT WED AUG 8 2012
FOR THE REMAINDER OF THE NIGHT...WITH QUASISTATIONARY BOUNDARY IN
THE AREA...AND WEAK UPPER LEVEL WAVES...INCLUDING REMNANT MCV
MOVING THROUGH SRN GREAT LAKES...EXPECT SCATTERED THUNDERSTORMS.
COVERAGE HAS BEEN SLOW TO EXPAND THUS FAR THIS EVENING...ALTHOUGH
THERE IS SOME HINT IN SREF PROBABILITIES...RAP...AND HRRR THAT
EXPANSION OF COVERAGE MAY OCCUR WITH A SLIGHT INCREASE IN MID
LEVEL FLOW LATE TONIGHT. CONSIDERING THIS...HAVE DEPICTED 40 TO 50
POPS WITH SCATTERED WORDING THROUGHOUT...AND POPS HIGHEST IN
VICINITY OF THE BOUNDARY. ISOLATED STRONG STORM CANNOT BE RULED
OUT...AND 5 PERCENT/SEE TEXT ON DAY ONE OUTLOOK PERFECTLY REASONABLE.
INCREASED CLOUD COVER AND AS A RESULT...IN CONCERT WITH LATEST
HOURLY NUMERICAL GUIDANCE AND OBSERVATIONAL TRENDS...BUMPED MIN
TEMPS UP SLIGHTLY IN SOME PORTIONS OF THE AREA. STILL MID 60S TO
AROUND 70...JUST SOME MINOR TWEAKS TO INDIVIDUAL NUMBERS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 246 PM EDT WED AUG 8 2012
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES WILL AFFECT THE
FORECAST AREA DURING THIS PERIOD. ONE WAVE...CURRENTLY OVER THE
UPPER MISSISSIPPI VALLEY...IS EXPECTED TO MOVE THROUGH THURSDAY
AFTERNOON AND EVENING. THIS WILL BE FOLLOWED BY AN UPPER LOW WHICH
WILL SETTLE INTO THE GREAT LAKES BY FRIDAY AND SATURDAY.
A SURFACE LOW ASSOCIATED WITH THE FIRST UPPER WAVE IS EXPECTED TO
MOVE ACROSS NORTHERN INDIANA THURSDAY AFTERNOON...WHICH WILL DRAG A
COLD FRONT THROUGH THE FORECAST AREA LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. THIS SETUP LOOKS TO PROVIDE THE BEST CHANCES FOR
PRECIPITATION DURING THIS PERIOD. DEEP LAYER SHEAR IS INITIALLY
RATHER WEAK...BUT GETS PROGRESSIVELY STRONGER TOWARDS THE LATE
AFTERNOON AND EARLY EVENING HOURS ON THURSDAY. MID LEVEL LAPSE RATES
ARE MARGINALLY FAVORABLE FOR SEVERE STORMS...SO THERE IS SOME
POTENTIAL FOR STORM ORGANIZATION AND ATTENDANT THREAT FOR MAINLY
WIND DAMAGE GIVEN THE INCREASING DEEP SHEAR. WILL CONTINUE TO
MENTION POPS FOR THURSDAY AND THURSDAY NIGHT...WITH THE HIGHEST POPS
AROUND FRONTAL PASSAGE...FROM MID AFTERNOON THURSDAY UNTIL ABOUT
MIDNIGHT THURSDAY NIGHT.
WILL KEEP A SMALL POP IN THE FORECAST FOR FRIDAY WITH THE UPPER LOW
IN THE AREA. APPEARS BY SATURDAY...THE UPPER LOW WILL HAVE DRIFTED
FAR ENOUGH OFF TO THE NORTHEAST TO KEEP THAT PERIOD DRY.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR THURSDAY
ARE PROBABLY ABOUT 3-6 DEGREES TOO LOW. THE HIGHS ON FRIDAY LOOK
BETTER...BUT MAY STILL BE A LITTLE COOL. GUIDANCE LOWS LOOK OK AT
THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 246 PM EDT WED AUG 8 2012
MODELS HAVE LOW RAIN CHANCES AT TIMES...BUT CONSIDERING RECENT
BIASES A TOTALLY DRY FORECAST BEST BET.
EUROPEAN MOS AND MEX TEMPS CLOSE THROUGH PERIOD. FOR MINS...CONSALL
MODEL WE INITIALIZED WITH IS ALSO CLOSE AND SEE NO REASON TO
CHANGE.
EVERYTHING AGREES GRADUAL WARMING THROUGH THE PERIOD. GIVEN RECENT
BIASES IN WARMING SITUATIONS WILL GO A FEW DEGREES ABOVE EVEN
RELATIVELY HOT CONSALL.
&&
.AVIATION /DISCUSSION FOR 090000Z TAF ISSUANCE/...
ISSUED AT 700 PM EDT WED AUG 8 2012
EXPECT SOME THUNDERSTORMS ACROSS CENTRAL INDIANA TONIGHT AND
THURSDAY AS A QUASI-STATIONARY BOUNDARY COMBINES WITH UPPER WAVES
AND INSTABILITY. AWIPS DISTANCE AND SPEED TOOL SUGGESTS THUNDERSTORM
ACTIVITY WILL BE IN THE LAF AREA NEAR ISSUANCE TIME. WITH LIKELY
POPS THERE TONIGHT...WILL GO WITH PREVAILING -TSRA FOR THE FIRST TWO
HOURS OF THE TAF FOLLOWED BY 4 HOURS TEMPO -TSRA...AS RAPID REFRESH
SUGGESTS ADDITIONAL ACTIVITY WILL MOVE INTO THE AREA. NEXT BEST
CHANCE OF THUNDERSTORMS WILL BE AFTER 18Z TOMORROW AS AN UPPER WAVE
AND DEEPER MOISTURE APPROACHES. FOR THE OTHER SITES...NOT CONFIDENT
ENOUGH TO GO WITH ANYTHING MORE THAN VCTS TONIGHT WITH PROB30 GROUP
AFTER 18Z THURSDAY. CONDITIONS SHOULD BE VFR OUTSIDE OF
THUNDERSTORMS PER MODEL TIME SECTIONS MOISTURE PROFILE. WINDS WILL
BE LIGHT TO CALM TONIGHT BEFORE BECOMING SOUTHWEST AT LESS THAN 10
KNOTS THURSDAY AS THE FRONT LIFTS NORTH OF THE TERMINALS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...NIELD
SHORT TERM...JAS
LONG TERM....JK
AVIATION...MK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1122 PM MDT MON AUG 6 2012
.UPDATE...
ISSUED AT 415 PM MDT MON AUG 6 2012
UPDATED TO INCLUDE THUNDERSTORM CHANCES IN THE WEST. CONVECTION
HAS INITIATED ALONG A SURFACE TROUGH IN NORTHEAST COLORADO. STORM
MOTIONS ARE ALMOST DUE SOUTH SO NOT SURE HOW FAR EAST THESE WILL
BE ABLE TO MOVE THIS EVENING. FURTHERMORE...DEW POINTS ARE QUITE
LOW. FOR THOSE REASONS...LIMITED POPS TO 30 IN THE FAR NORTHWEST
AND 20 ELSEWHERE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 236 PM MDT MON AUG 6 2012
THROUGH TONIGHT...SHORTWAVE TROUGH WILL TRANSLATE SOUTHEASTWARD THE
NORTHERN PLAINS. STRONGEST FORCING FOR ASCENT WILL REMAIN NORTHEAST
OF THE FORECAST AREA. HOWEVER...WITH A SURFACE LOW DEVELOPING ACROSS
NORTHEAST COLORADO...DO EXPECT ISOLATED TO SCATTERED THUNDERSTORMS
TO DEVELOP ACROSS NORTHERN/NORTHEASTERN PORTIONS OF THE FORECAST
AREA AFTER 06Z. WILL ALSO NEED TO MONITOR A WEAK AREA OF SURFACE
CONVERGENCE JUST TO THE WEST OF THE FORECAST AREA WHERE A SHALLOW CU
FIELD CONTINUES TO DEVELOP. LATEST RUNS OF THE HRRR DEVELOP
CONVECTION IN THIS AREA WITH A GENERAL EASTWARD/SOUTHEASTWARD
MOVEMENT. NOT COMPLETELY SOLD ON THIS SOLUTION SO OPTING TO KEEP
POPS OUT OF THE FORECAST FOR NOW. WILL NEED TO MONITOR AND
REEVALUATE AS THE AFTERNOON GOES ON.
TUESDAY...SLIGHTLY STRONGER SHORTWAVE TROUGH WILL BEGIN TO IMPACT
THE REGION DURING THE DAY TUESDAY. WILL LIKELY SEE A LULL IN PRECIP
DURING THE MORNING HOURS IN THE WAKE OF THE DEPARTING OVERNIGHT
SYSTEM WITH PRECIP CHANCES INCREASING DURING THE AFTERNOON HOURS.
DEEP LAYER SHEAR WILL INCREASE TO AROUND 30-35 KTS DURING THE
AFTERNOON HOURS WHICH WILL HELP ORGANIZE THUNDERSTORM UPDRAFTS. ONE
LIMITING FACTOR WILL BE MINIMAL AVAILABLE INSTABILITY WITH SBCAPE
VALUES OF 500-1000 J/KG. POINT SOUNDINGS DO INDICATE AN INVERTED-V
STRUCTURE SO WOULD ANTICIPATE GUSTY OUTFLOW WINDS BEING THE PRIMARY
THREAT TOMORROW AFTERNOON/EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 236 PM MDT MON AUG 6 2012
TUESDAY NIGHT-THURSDAY...LARGE SCALE H5 RIDGE WILL AMPLIFY OVER THE
NORTHERN ROCKIES THROUGH THE PERIOD...WITH MAIN CONCERN BEING THE
CHANCE FOR LINGERING PRECIPITATION OVER PORTIONS OF THE CWA TUESDAY
NIGHT WITH PRECIPITATION CHANCES LOOKING TO BE VERY SMALL AFTER THAT
LARGE SCALE SUBSIDENCE OVERSPREADS THE AREA WITH DEEP LAYER FLOW
ALOFT OUT OF THE NORTH-NORTHWEST KEEPING ANY DEEP MOISTURE RETURN TO
THE AREA LIMITED. FOR TUESDAY NIGHT HOWEVER...DIV Q FIELDS SUGGEST LARGE
SCALE SUBSIDENCE WILL OVERSPREAD THE CWA AFTER 03Z...WHICH SHOULD
BEGIN TO DIMINISH PRECIPITATION POTENTIAL PRETTY QUICKLY OVERNIGHT.
WHILE THERE WILL BE LARGE SCALE SUBSIDENCE...THINK THERE WILL BE AT
LEAST A SHORT WINDOW FOR PRECIPITATION DURING THE EVENING
HOURS...MAINLY ALONG AND SFC TROUGH EXPECTED TO STRETCH FROM
FIRSTVIEW TO MCCOOK. WITH MIXED LAYER CINH VALUES FAIRLY HIGH AND
AFOREMENTIONED SUBSIDENCE CONFIDENCE IN PRECIPITATION FAIRLY LOW.
ALTHOUGH SREF AND GEFS HAVE FAIRLY HIGH PROBABILITIES (>75%) IN
EASTERN CWA...DO NOT THINK CONFIDENCE IS HIGH ENOUGH TO GO MORE THAN
20-40 PERCENT CHANCES THROUGH THE EVENING HOURS.
AS H5 RIDGE AMPLIFIES AND MUCH DRIER AIR WORKS INTO THE CWA...THINK
PRECIP CHANCES WILL REMAIN VERY LOW TO PRACTICALLY NOTHING THROUGH
THE REST OF THE PERIOD. SEEMS TO BE A FAIRLY LARGE SPREAD BETWEEN
MODELS WITH RESPECT TO HOW WARM THINGS WILL GET ACROSS THE AREA.
WHILE GFS IS MUCH COOLER THAN OTHER MODELS AND GIVEN THE OVERALL
FLOW PATTERN WOULD NOT BE UNHEARD OF FOR A COOLER AIR MASS TO BACK
INTO CWA. THAT BEING SAID...GFS HAS A FAIRLY WELL DOCUMENTED COLD
BIAS THIS SUMMER AND THINK OVERALL BIAS CORRECTED VALUES IN THE
MID/UPPER 90S LOOK REASONABLE. MUCH DRIER AIR IS EXPECTED TO MOVE
INTO THE AREA WEDNESDAY AFTERNOON ALLOWING RH`S TO APPROACH CRITICAL
VALUES. OVERALL DO NOT THINK CONDITIONS WILL BE LONG LASTING AND DO
NOT PLAN ON ISSUING ANY WATCHES AT THIS POINT AND THINK THE BIGGEST
IMPACT OF DRIER AIR MASS WILL BE TO ALLOW TEMPS TO BE RATHER COOL
GIVEN LIGHT WINDS/CLEAR SKIES AND DRY AIR.
IN THE EXTENDED (FRIDAY-NIGHT-MONDAY)...WHILE MEDIUM RANGE MODELS
START THE PERIOD IN REASONABLE AGREEMENT...DIFFERENCES EMERGE FAIRLY
QUICKLY IN THE PERIOD WITH RESPECT TO HANDLING OF SHORT WAVE TROUGH
MOVES AROUND TOP OF THE AMPLIFIED H5 RIDGE AND WHAT IMPACT...IF ANY
THIS TROUGH HAS ON LARGE SCALE RIDGE PATTERN. THESE DIFFERENCES DO
NOT LEAD TO A LOT OF CONFIDENCE IN FORECAST FROM SATURDAY ON...AND
PLAN ON KEEPING FORECAST NEAR CONSENSUS DATA FOR THE TIME BEING
UNTIL A BETTER FAVORED SOLUTION APPEARS...ALTHOUGH THINK WEIGHTING
BLENDS A BIT MORE TOWARDS THE ECWMF IS IN ORDER BASED ON THE GEFS
DATA. LATEST ECMWF HAS COME IN A BIT COOLER THAN PREVIOUS RUNS AND
GIVEN EASTERLY SFC FLOW AND STRONG HIGH AROUND BASE OF SFC HIGH
THINK A GENERAL COOLING TREND IS IN ORDER. WITH MOST NIGHTS NOT
REALLY BRINGING A CLEAR SIGNAL FOR WARM TEMPS (DENSE CLOUD
COVER...STRONG WINDS...ETC) HAVE WORKED THE 3-5 DEGREE COOLER BIAS
CORRECTED SOLUTIONS INTO OVERNIGHT LOW FORECASTS WHERE I COULD...TO
PICK UP OUR NORMALLY COLDEST SPOTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM MDT MON AUG 6 2012
SURFACE TROUGH NEAR THE COLORADO AND KANSAS STATE LINE WILL MOVE
LITTLE THROUGH TOMORROW RESULTING IN LIGHT AND VARIABLE WINDS.
PRECIPITATION CHANCES WILL BE LOW...LATEST MODEL GUIDANCE SUGGESTS
LIGHT RAIN SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM MOVING
OUT OF COLORADO LATE TONIGHT AND INTO TUESDAY MORNING. CONFIDENCE
IS NOT VERY GOOD...AS MODELS HAVE INITIALIZED FAR TOO WET...SO
DECIDED NOT TO MENTION ANY IN THE TAFS UNTIL RADAR TRENDS SUPPORT
IT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...024
SHORT TERM...FOLTZ
LONG TERM...JRM
AVIATION...024
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
331 PM EDT TUE AUG 7 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OFF THE COAST MIDWEEK...PERMITTING
SOUTHWEST FLOW TO BECOME ESTABLISHED. A COLD FRONT WILL ARRIVE LATE
FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
18Z SFC ANALYSIS SHOWS THE CENTER OF HIPRES HAS SHIFTED OFF THE
MID-ATLANTIC COAST. REMNANT SFC DEWPOINT BOUNDARY STRETCHING FROM
THE NRN PIEDMONT TO JUST SE OF I-95. THIS BOUNDARY WILL REMAIN
NEARLY STATIONARY THIS AFTN. DEWPOINTS IN THE LOW AND MID 60S RESIDE
NORTH AND WEST OF THE BOUNDARY...LOWER 70S TO THE SOUTH AND EAST.
BLENDED SAT AND RAP ANALYSIS SHOWED A TIGHT NW TO SE PWAT
GRADIENT...RANGING FROM UNDER INCH OVER THE ALLEGHENY FRONT TO JUST
UNDER TWO INCHES OVER THE SRN MD CHSPK BAY.
SCT SHOWERS AND TSTMS HAVE DEVELOPED ERY THIS AFTN SOUTH AND EAST OF
DC. EXPECT AN UPTICK IN THE ACTIVITY MID AFTN IN THIS MOIST/UNSTABLE
AIRMASS ALONG AND SOUTH/EAST OF THE BOUNDARY...WHERE MID-LVL LIFT IS
LOCATED AHEAD OF A WEAK SHORTWAVE TROUGH MOVING THRU SRN MD.
WITH LIGHT WINDS ALOFT...STORM MOTION WILL BE VERY WEAK. THE
SETUP SUPPORTS A LOCALIZED THREAT OF FLASH FLOODING IN THE NRN
PIEDMONT AND SRN MD. STILL CANNOT RULE OUT A PULSE SEVERE STORM OR
TWO GIVEN THE FAVORABLE ENVIRONMENT FOR A WET MICROBURST...
ALTHOUGH CLOUD COVER HAS LIMITED THE THREAT.
LGT SLY FLOW WILL OVERTAKE ENTIRE REGION TNGT AS HIPRES MOVES AWAY
FROM THE ERN SEABOARD. SIMILAR TO LAST NGT...CONVECTION WILL WANE
AFTER SUNSET...BUT A COUPLE OF SHOWERS AND STORMS MAY LINGER
OVNGT...ESPECIALLY IN SRN MD. ANOTHER MUGGY NGT IS EXPECTED WITH
MIN TEMPS IN THE 60S WELL NORTH AND WEST OF THE DC AND
BALTIMORE...LOW 70S IN THE NEARBY SUBURBS AND MID 70S IN THE CITIES.
THE DIFFUSE BOUNDARY WILL REMAIN OVER THE REGION WED...BUT SHOULD
START TO PROGRESS NWD. SHOWERS AND STORMS EXPECTED TO DEVELOP AGAIN
IN THE WARM/MOIST AIRMASS...ESPECIALLY EAST OF THE BLUE RIDGE. GIVEN
LACK OF SYNOPTIC LIFT... COVERAGE SHOULD BE ISO.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AN UPPER-LEVEL TROUGH WILL APPROACH THE CWA DURING THE SECOND HALF
OF THE WORK WEEK. THIS WILL PRODUCE SHOWERS AND THUNDERSTORMS...SOME
OF WHICH COULD BE SEVERE...BOTH THURS AND FRI AFTERNOONS. CONTINUING
SOUTHWEST FLOW INTO THE AREA WILL MAINTAIN A WARM HUMID AIRMASS
THROUGH MIDWEEK. THIS COMBINED WITH THE PASSAGE OF A SHORTWAVE PRIOR
TO THE MAIN UPPER-TROUGH WILL PROVIDE SUFFICIENT LIFT FOR TSTMS
THURS AFTERNOON. BY FRI...A COLD FRONT LOOKS TO BE POSITIONED JUST
TO THE REGION/S WEST WITH ANOTHER WIDER SPREAD ROUND OF SEVERE
WEATHER IN THE AFTERNOON HOURS. BOTH DAYS HAVE BEEN OUTLOOKED BY SPC
WITH A SLIGHT RISK FOR THE CWA DURING DAYS 3 AND 4.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
GUIDANCE DEPICTS THE ACTUAL FRONT TRANSITIONING ACROSS THE AREA
DURING THE DAY SATURDAY WITH HIGH PRESSURE BUILDING IN BEHIND. THIS
WILL LOWER TEMPS BY 5-10 DEGREES TO VALUES A LITTLE COOLER THEN
NORMAL FOR THE BEGINNING OF AUGUST. PRECIP COULD LINGER THROUGH THE
DAY SATURDAY AS THE FRONT SLOWLY MOVES OFFSHORE. HOWEVER...THE
THREAT OF SEVERE STORMS WILL BE CONFINED TO THURS AND FRI. WIND WILL
SHIFT TO NORTHWEST BRINGING DRIER AIR INTO THE REGION FOR THE
BEGINNING OF THE WEEK. EXPECT MOSTLY DRY CONDITIONS WITH DAYTIME
HIGHS IN THE MID 80S AND LOWS IN THE MID 60S FOR SUN THROUGH TUE.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
MVFR AND IFR VSBYS ARE EXPECTED ACROSS AREA TERMINALS TONIGHT AS A
HUMID AIR MASS REMAINS OVER THE REGION. CHO SHOULD SEE THE BIGGEST
DROP IN VSBY AS THE AREA COULD SEE SOME SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON. ELSEWHERE WITH THE EXCEPTION OF
DCA...SHOULD SEE REDUCTIONS TO AROUND 3 SM. WIND WILL SLOWLY SHIFT
FROM NORTHEAST TO SOUTHWEST THROUGH THE TAF VALID PERIOD. THE
SOUTHWESTERLY SHIFT IN WIND DIRECTION WILL HELP TO MAINTAIN LOW
LEVEL BUT VFR CIGS THROUGH THE DAY TOMORROW.
AN UPPER LOW WILL DEEPEN OVER THE UPPER MIDWEST AND GREAT LAKES LATE
THIS WEEK WHILE AN ASSOCIATED COLD FRONT MOVES THRU FRI NGT OR SAT.
UNSETTLED WX WILL OCCUR DURING THIS TIME...WITH HIGH CHANCES FOR
PRECIP THU-SAT. SOME STORMS MAY BE STRONG DURING THE AFTN HRS THU
AND FRI. VSBY RESTRICTIONS IN STORMS LIKELY.
&&
.MARINE...
A RESIDUAL BOUNDARY REMAINS STATIONARY OVER THE CENTRAL MD CHSPK
BAY....WITH SLY FLOW OCCURRING SOUTH OF NORTH BEACH AND NELY FLOW TO
THE NORTH. THE BOUNDARY WILL SLOWLY LIFT NWD WED. ENHANCED SLY FLOW
DUE TO CHANNELING SOUTH OF THE BOUNDARY WILL STILL REMAIN BELOW SCA
THRESHOLD THRU WED. ISO SHOWERS AND STORMS MAY LINGER INTO THE
NGT...THOUGH NOT AS STRONG AND WIDESPREAD AS THIS AFTN. THREAT OF
STORMS CONTINUE WED.
LOPRES AND ASSOCIATED COLD FRONT WILL APPROACH FROM THE WEST THU
BEFORE MOVING THRU FRI AND SAT...RESULTING IN A PROLONGED PERIOD OF
SHOWERS AND STORMS DURING THIS TIME. SOME OF THE STORMS MAY BE
STRONG THU AND FRI AFTN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
KLEIN/CLS
AREA FORECAST DISCUSSION...CORRECTED
NWS BALTIMORE MD/WASHINGTON DC
1029 AM EDT TUE AUG 7 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL MOVE OFFSHORE TODAY...PERMITTING
SOUTHWEST FLOW TO BECOME ESTABLISHED THROUGH THE END OF THE WEEK.
A COLD FRONT WILL ARRIVE BY LATE FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
REMNANT FRONTAL BOUNDARY REMAINS STATIONARY OVER THE NRN PIEDMONT
AND SRN MD THIS MRNG. LIGHT NLY FLOW AND DEWPOINTS IN THE 60S RESIDE
NORTH OF THE BOUNDARY WITH LIGHT SLY FLOW AND DEWPOINTS IN THE
LOWER 70S TO THE SOUTH. BLENDED SAT AND RAP ANALYSIS SHOWED A
TIGHT NW TO SE PWAT GRADIENT...RANGING FROM THREE-QUARTER INCH
OVER CBE TO ALMOST TWO INCHES OVER NHK. 12Z IAD RAOB SHOWED A VERY
DRY AIRMASS ABOVE H7 AND PWAT OF 1.2 INCH.
WEAK CONVERGENCE ALONG THE BOUNDARY AND THE APPROACH OF A SUBTLE
SHORTWAVE TROUGH HAS PROVIDED ENOUGH FORCING TO TRIGGER SHOWERS AND
STORMS IN LOWER SRN MD THIS MRNG. WITH WEAK FLOW ALOFT AND A STALLED
BOUNDARY...STORMS HAD LITTLE MOVEMENT OVER ST MARYS...RESULTING IN
RADAR ESTIMATED RAINFALL OF 3 INCHES IN JUST OVER AN HOUR. THE
ENVIRONMENT WILL NOT CHANGE MUCH TDA AND WILL BE FAVORABLE FOR A
LOCALIZED THREAT OF FLASH FLOODING IN FAR SRN ZONES OF THE CWA.
SUBSIDENCE BEHIND THE UPPER SHORTWAVE TROUGH SHOULD LIMIT COVERAGE
OF STORMS THIS AFTN IN SRN MD AND EVERYWHERE FOR THAT MATTER. SOUTH
OF THE BOUNDARY...A FEW SHOWERS AND STORMS STILL EXPECTED TO DEVELOP
IN THE MOIST/UNSTABLE AIRMASS OVER CENTRAL VA AND SRN MD. IF SOME
PERSISTENT BREAKS IN MRNG CLOUD COVER DEVELOP THIS AFTN...THEN ONE
OR TWO STORMS IN CENTRAL VA AND SRN MD COULD BECOME PULSE SEVERE
GIVEN THE FAVORABLE ENVIRONMENT FOR A WET MICROBURST.
MODEL MAX T HAS BEEN RUNNING SVRL DEGREES TOO COOL FOR SVRL DAYS
NOW. DONT FORSEE AMS TDA TO BE ANY COOLER THAN YDA. IF ANYTHING H8
TEMPS WL RISE BY ANTHR DEG OR SO. THEREFORE...HV BASED MAXT FCST
ON PERSISTENCE MORE THAN MOS...AND WL BE COMING IN A FEW DEG HIER
THAN THE WARMEST OFFERING. MIN-T SEEMS MORE REASONABLE...IN STEP
W/ DEWPTS...AND HV BLENDED W/ MET.
&&
.SHORT TERM /WEDNESDAY/...
AFTER BEING HELD DOWN ACROSS THE VA/NC BORDER FOR A COUPLE OF
DAYS...THE STATIONARY BOUNDARY WILL BEGIN TO LIFT TOWARD THE NORTH
ON WED. THE BOUNDARY THOUGH WILL WASH-OUT AND WILL BASICALLY MORPH
INTO A CONVERGENCE ZONE FOR PRECIP ALONG THE SRN ATLC COAST. AS THIS
CORRIDOR ORIENTS ITSELF FROM SW-NE...IT WILL ALSO ALLOW FOR SOME
WEAKER AREAS OF LIFT TO EXIST ALONG THE I-95 CORRIDOR - ALONG W/ A
TIGHT MOISTURE GRADIENT. DEWPOINTS ACROSS THE MTNS WILL DROP DOWN
INTO THE 50S AND EFFECTIVELY END PRECIP CHANCES FOR THE DAY...WHILE
L70S EXIST E OF THE BLUE RIDGE. ISOLATED SHOWERS/TSTMS WILL BE
POSSIBLE ACROSS THESE AREAS...ESPECIALLY CLOSER TO THE BAY. THIS
WILL ALSO RESULT IN BALMY CONDITIONS FOR THE METRO AREAS...BUT MORE
COMFORTABLE ACROSS THE VLYS/MTNS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
CHANGES WILL COME GRADUALLY OVER THE SECOND HALF OF THE WEEK.
SEVERAL UPPER VORT LOBES WILL SWING AROUND A POSITIVELY TILTED UPPER
TROF SLIDING DOWN FROM THE GREAT LAKES REGION. AS THE FIRST ONE
APPROACHES ON THU AFTN...SHOWERS AND TSTMS WILL BE ON THE INCREASE
FROM WEST-TO-EAST BUT MAINLY FOR LATER IN THE DAY AND OVERNIGHT.
EMBEDDED AREAS OF CONVECTION WILL BE POSSIBLE W/ THE OVERNIGHT
ACTIVITY...BUT THERE WILL BE MUCH LOWER INSTABILITY AT THAT POINT.
AFTER A BRIEF LULL EARLY FRI...THE NEXT UPPER VORT WILL THEN PULL
THE TROF AXIS DOWN ACROSS THE AREA. THIS WILL BRING A GOOD CHANCE
FOR MORE WIDESPREAD SHOWERS AND SOME EMBEDDED SCATTERED STORMS. THE
TROUGH AXIS WILL THEN TURN INTO A CUT-OFF UPPER LOW THAT MOST LONG
TERM GUIDANCE AGREES WILL TAKE OFF TOWARD NEW ENGLAND BUT NOT BEFORE
DEVELOPING SOME SHOWERS ACROSS THE ERN HALF OF THE CWA ON SAT.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
CHO WAS THE ONLY SIDE BELOW VFR AT 12Z TAF ISSUANCE...BUT HAS SINCE
IMPROVED TO VFR. AREA CAUGHT BTWN DRY AIR ATTEMPTING TO SNEAK SWD
FM PA WHILE HUMID AIR RIDES NEWD TDA. IT/LL LEAD TO LOTSA
CLDCVR...BUT SUSPECT MOST OF IT WL BE MID DECK...IE VFR FLGT CONDS
WL GNLY PREVAIL.
VERY SMALL CHANCE /AROUND 20 PERCENT/ FOR AN ISO SHOWER OR STORM
TO BRIEFLY IMPACT CHO THIS AFTN OR ERY EVE. THUS LIKELIHOOD IS TOO
LOW TO INCLUDE IN TAFS.
SAME AIRMASS TNGT...WHICH COULD LEAD TO ANOTHER ROUND OF
FOG AT MRB/CHO. BASED ON WHAT HAPPENED THIS MRNG...LOCAL
RESTRICTION MAY DROP INTO IFR RANGE ERY WED MRNG.
MAINLY DRY ON WED...THOUGH A FEW SHOWERS/TSTMS MAY DEVELOP ALONG
THE I-95 CORRIDOR AFTER SOME DAYTIME HEATING LATER IN THE AFTN-EVE
HRS. A MORE POTENT LOW PRESSURE SYSTEM WILL THEN APPROACH THE AREA
ON THU...BRINGING ANOTHER CHANCE FOR PRECIP THU AFTN THROUGH SAT
MRNG - FRI BEING THE BEST CHANCE FOR WIDESPREAD SHOWER/TSTM
ACTIVITY. WINDS WILL BE MAINLY LIGHT EACH DAY...W/ A STEADY SLY
BREEZE EACH AFTN THIS WEEK.
&&
.MARINE...
COMPLEX FLOW ACRS THE REGION. GNLY WSWLY WNDS PREVAIL...THO NRN BAY
STILL REFLECTS WK NNELY FLOW FM THE COOLER/DRIER AIR PARKED ACRS
PA.
OVER THE COURSE OF THE DAY...THE SLY FLOW WL WIN OUT...AND MAY
RESULT IN A LTL CHANNELING BY DAYS END. NO FLAGS XPCTD. MAY ALSO HV
A CPL AFTN-EVE TSTMS OVER THE LOWER TIDAL POTOMAC AND MD CHSPK
BAY. CANNOT RULE OUT THE ISSUANCE OF ONE OR TWO SMWS FOR GUSTY
TSTM WINDS.
LIGHT WINDS HEADING INTO WED...THOUGH A FEW BRIEF PERIODS OF SLY
CHANNELING W/ DEVELOP OVER THE LOWER BAY PERIODICALLY THRU THE END
OF THE CURRENT WEEK. AN UPPER LOW WILL THEN GLIDE JUST TO OUR NORTH
THU/FRI...BRINGING MORE PRECIP CHANCES TO AREA TO CLOSE OUT THE WORK
WEEK. THE UPPER LOW WILL THEN RACE OFF TOWARD NEW ENGLAND THIS
WEEKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...KLEIN
PREV DISC...HTS/GMS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
959 AM EDT TUE AUG 7 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL MOVE OFFSHORE TODAY...PERMITTING
SOUTHWEST FLOW TO BECOME ESTABLISHED THROUGH THE END OF THE WEEK.
A COLD FRONT WILL ARRIVE BY LATE FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
REMNANT FRONTAL BOUNDARY REMAINS STATIONARY OVER THE NRN PIEDMONT
AND SRN MD THIS MRNG. LIGHT NLY FLOW AND DEWPOINTS IN THE 60S RESIDE
NORTH OF THE BOUNDARY WITH LIGHT SLY FLOW AND DEWPOINTS IN THE
LOWER 70S TO THE SOUTH. BLENDED SAT AND RAP ANALYSIS SHOWED A
TIGHT NW TO SE PWAT GRADIENT...RANGING FROM THREE-QUARTER INCH
OVER CBE TO ALMOST TWO INCHES OVER NHK. 12Z IAD RAOB SHOWED A VERY
DRY AIRMASS ABOVE H7 AND PWAT OF 1.2 INCH.
WEAK CONVERGENCE ALONG THE BOUNDARY AND THE APPROACH OF A SUBTLE
SHORTWAVE TROUGH HAS PROVIDED ENOUGH FORCING TO TRIGGER SHOWERS AND
STORMS IN LOWER SRN MD THIS MRNG. WITH WEAK FLOW ALOFT AND A STALLED
BOUNDARY...STORMS HAD LITTLE MOVEMENT OVER ST MARYS...RESULTING IN
RADAR ESTIMATED RAINFALL OF 3 INCHES IN JUST OVER AN HOUR. THE
ENVIRONMENT WILL NOT CHANGE MUCH TDA AND WILL BE FAVORABLE FOR A
LOCALIZED THREAT OF FLASH FLOODING IN FAR SRN ZONES OF THE CWA.
SUBSIDENCE BEHIND THE UPPER SHORTWAVE TROUGH SHOULD LIMIT COVERAGE
OF STORMS THIS AFTN IN SRN MD AND EVERYWHERE FOR THAT MATTER. SOUTH
OF THE BOUNDARY...A FEW SHOWERS AND STORMS STILL EXPECTED TO DEVELOP
IN THE MOIST/UNSTABLE AIRMASS OVER CENTRAL VA AND SRN MD. IF SOME
PERSISTENT BREAKS IN MRNG CLOUD COVER DEVELOP THIS AFTN...THEN ONE
OR TWO STORMS IN CENTRAL VA AND SRN MD COULD BECOME PULSE SEVERE
GIVEN THE FAVORABLE ENVIRONMENT FOR A WET MICROBURST.
MOS MAXT HAS BEEN RUNNING SVRL DEGF TOO WARM FOR SVRL DAYS NOW. DONT
FORSEE AMS TDA TO BE ANY COOLER THAN YDA. IF ANYTHING H8 TEMPS WL
RISE BY ANTHR DEG OR SO. THEREFORE...HV BASED MAXT FCST ON
PERSISTENCE MORE THAN MOS...AND WL BE COMING IN A FEW DEG HIER THAN
THE WARMEST OFFERING. MIN-T SEEMS MORE REASONABLE...IN STEP W/
DEWPTS...AND HV BLENDED W/ MET.
&&
.SHORT TERM /WEDNESDAY/...
AFTER BEING HELD DOWN ACROSS THE VA/NC BORDER FOR A COUPLE OF
DAYS...THE STATIONARY BOUNDARY WILL BEGIN TO LIFT TOWARD THE NORTH
ON WED. THE BOUNDARY THOUGH WILL WASH-OUT AND WILL BASICALLY MORPH
INTO A CONVERGENCE ZONE FOR PRECIP ALONG THE SRN ATLC COAST. AS THIS
CORRIDOR ORIENTS ITSELF FROM SW-NE...IT WILL ALSO ALLOW FOR SOME
WEAKER AREAS OF LIFT TO EXIST ALONG THE I-95 CORRIDOR - ALONG W/ A
TIGHT MOISTURE GRADIENT. DEWPOINTS ACROSS THE MTNS WILL DROP DOWN
INTO THE 50S AND EFFECTIVELY END PRECIP CHANCES FOR THE DAY...WHILE
L70S EXIST E OF THE BLUE RIDGE. ISOLATED SHOWERS/TSTMS WILL BE
POSSIBLE ACROSS THESE AREAS...ESPECIALLY CLOSER TO THE BAY. THIS
WILL ALSO RESULT IN BALMY CONDITIONS FOR THE METRO AREAS...BUT MORE
COMFORTABLE ACROSS THE VLYS/MTNS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
CHANGES WILL COME GRADUALLY OVER THE SECOND HALF OF THE WEEK.
SEVERAL UPPER VORT LOBES WILL SWING AROUND A POSITIVELY TILTED UPPER
TROF SLIDING DOWN FROM THE GREAT LAKES REGION. AS THE FIRST ONE
APPROACHES ON THU AFTN...SHOWERS AND TSTMS WILL BE ON THE INCREASE
FROM WEST-TO-EAST BUT MAINLY FOR LATER IN THE DAY AND OVERNIGHT.
EMBEDDED AREAS OF CONVECTION WILL BE POSSIBLE W/ THE OVERNIGHT
ACTIVITY...BUT THERE WILL BE MUCH LOWER INSTABILITY AT THAT POINT.
AFTER A BRIEF LULL EARLY FRI...THE NEXT UPPER VORT WILL THEN PULL
THE TROF AXIS DOWN ACROSS THE AREA. THIS WILL BRING A GOOD CHANCE
FOR MORE WIDESPREAD SHOWERS AND SOME EMBEDDED SCATTERED STORMS. THE
TROUGH AXIS WILL THEN TURN INTO A CUT-OFF UPPER LOW THAT MOST LONG
TERM GUIDANCE AGREES WILL TAKE OFF TOWARD NEW ENGLAND BUT NOT BEFORE
DEVELOPING SOME SHOWERS ACROSS THE ERN HALF OF THE CWA ON SAT.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
CHO WAS THE ONLY SIDE BELOW VFR AT 12Z TAF ISSUANCE...BUT HAS SINCE
IMPROVED TO VFR. AREA CAUGHT BTWN DRY AIR ATTEMPTING TO SNEAK SWD
FM PA WHILE HUMID AIR RIDES NEWD TDA. IT/LL LEAD TO LOTSA
CLDCVR...BUT SUSPECT MOST OF IT WL BE MID DECK...IE VFR FLGT CONDS
WL GNLY PREVAIL.
VERY SMALL CHANCE /AROUND 20 PERCENT/ FOR AN ISO SHOWER OR STORM
TO BRIEFLY IMPACT CHO THIS AFTN OR ERY EVE. THUS LIKELIHOOD IS TOO
LOW TO INCLUDE IN TAFS.
SAME AIRMASS TNGT...WHICH COULD LEAD TO ANOTHER ROUND OF
FOG AT MRB/CHO. BASED ON WHAT HAPPENED THIS MRNG...LOCAL
RESTRICTION MAY DROP INTO IFR RANGE ERY WED MRNG.
MAINLY DRY ON WED...THOUGH A FEW SHOWERS/TSTMS MAY DEVELOP ALONG
THE I-95 CORRIDOR AFTER SOME DAYTIME HEATING LATER IN THE AFTN-EVE
HRS. A MORE POTENT LOW PRESSURE SYSTEM WILL THEN APPROACH THE AREA
ON THU...BRINGING ANOTHER CHANCE FOR PRECIP THU AFTN THROUGH SAT
MRNG - FRI BEING THE BEST CHANCE FOR WIDESPREAD SHOWER/TSTM
ACTIVITY. WINDS WILL BE MAINLY LIGHT EACH DAY...W/ A STEADY SLY
BREEZE EACH AFTN THIS WEEK.
&&
.MARINE...
COMPLEX FLOW ACRS THE REGION. GNLY WSWLY WNDS PREVAIL...THO NRN BAY
STILL REFLECTS WK NNELY FLOW FM THE COOLER/DRIER AIR PARKED ACRS
PA.
OVER THE COURSE OF THE DAY...THE SLY FLOW WL WIN OUT...AND MAY
RESULT IN A LTL CHANNELING BY DAYS END. NO FLAGS XPCTD. MAY ALSO HV
A CPL AFTN-EVE TSTMS OVER THE LOWER TIDAL POTOMAC AND MD CHSPK
BAY. CANNOT RULE OUT THE ISSUANCE OF ONE OR TWO SMWS FOR GUSTY
TSTM WINDS.
LIGHT WINDS HEADING INTO WED...THOUGH A FEW BRIEF PERIODS OF SLY
CHANNELING W/ DEVELOP OVER THE LOWER BAY PERIODICALLY THRU THE END
OF THE CURRENT WEEK. AN UPPER LOW WILL THEN GLIDE JUST TO OUR NORTH
THU/FRI...BRINGING MORE PRECIP CHANCES TO AREA TO CLOSE OUT THE WORK
WEEK. THE UPPER LOW WILL THEN RACE OFF TOWARD NEW ENGLAND THIS
WEEKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...KLEIN
PREV DISC...HTS/GMS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
433 AM EDT TUE AUG 7 2012
.SYNOPSIS...
DRY AND MILD CONDITIONS WILL CONTINUE THROUGH MOST OF WEDNESDAY AS
HIGH PRESSURE PUSHES EAST OF THE AREA. A COLD FRONT WILL APPROACH
FROM THE NORTHWEST LATE ON WEDNESDAY AND BRING A SLIGHT CHANCE OF
THUNDERSTORMS. A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL
RETURN TO THE REGION THURSDAY INTO FRIDAY WHEN A LOW PRESSURE
SYSTEM CROSSES THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A DRY AND WEAK ZONAL FLOW. AT THE SURFACE, A BROAD AREA OF HIGH
PRESSURE EXTENDS FROM THE MISSOURI VALLEY ACROSS THE OHIO VALLEY
AND INTO THE MID-ATLANTIC. ASIDE FROM SOME CIRRUS PUSHING EAST OF
PITTSBURGH SKIES ARE CLEAR THIS MORNING.
CLEARING FROM THE WEST WILL CONTINUE THIS MORNING AS UPPER LEVEL
MOISTURE PUSHES EASTWARD. BROAD HIGH PRESSURE WILL CONTINUE TO
DOMINATE TODAY AND TONIGHT. THIS WILL ALLOW FOR CLEAR SKIES
THROUGH THIS PERIOD. DESPITE ABUNDANT SUNSHINE, HIGHS TODAY ARE
CLOSER TO THE COOLER MAV GUIDANCE, RANGING FROM THE LOWER 80S
ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES TO THE UPPER 80S
ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV. ONE MORE
NIGHT OF RADIATIONAL COOLING WILL OCCUR TONIGHT WITH MOSTLY CLEAR
SKIES AND NEAR CALM WINDS. WITH A SLIGHT SOUTHERLY COMPONENT TO
WINDS THIS WILL ALLOW FOR A SLIGHTER WARMER NIGHT ACROSS MOST
LOCATIONS WITH LOWS RANGING FROM THE UPPER 50S TO THE LOWER 60S.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
THERE IS GFS/ECMWF/NAM AGREEMENT THAT BENIGN WEATHER WILL CONTINUE
EARLY ON WEDNESDAY WITH A DEEP LAYER OF DRY AIR IN PLACE. A WEAK
SHORT WAVE WILL MOVE EASTWARD ACROSS THE AREA AND A COLD FRONT
WILL DROP SOUTHEASTWARD INTO THE REGION LATE IN THE DAY. 850-700MB
OMEGA INDICATES THERE MAY BE ENOUGH FORCING FOR A FEW SHOWERS OR
THUNDERSTORMS TO DEVELOP ALTHOUGH MOISTURE WILL STILL BE FAIRLY
LIMITED. THUS, WENT WITH SCHC POPS FOR LATE IN THE DAY. WITH THE
LOSS OF HEATING, ANY CONVECTION WILL DIMINISH WEDNESDAY NIGHT.
WEAK WARM AIR ADVECTION AHEAD OF THE FRONT WILL ALLOW FOR TEMPS TO
WARM TO AROUND 5 DEGREES ABOVE NORMAL FOR HIGHS. WITH WARM TD
ADVECTION ONGOING, TEMPS WILL ONLY DROP TO THE MID 60S ACROSS MOST
OF THE AREA WEDNESDAY NIGHT.
FOR THURSDAY INTO FRIDAY, A BLEND OF THE GFS/ECMWF WAS USED TO
DEPICT A MID-LEVEL LONG WAVE TROUGH SWINGING FROM THE UPPER MIDWEST
INTO THE OHIO VALLEY AND A WEAK SURFACE LOW MOVING FROM THE
MISSOURI VALLEY INTO THE UPPER OHIO VALLEY. ON THURSDAY, THE
INITIAL COLD FRONT WILL SLIDE ACROSS THE AREA WITH MODERATE
INSTABILITY DEVELOPING. HIGH TEMPS WILL BE A FEW DEGREES ABOVE
NORMAL AHEAD OF THE FRONT. HIGH CHANCE POPS WILL CONTINUE INTO
FRIDAY WITH SYNOPTIC FORCING FROM THE LOW AS IT CROSSES THE AREA.
IN THE WAKE OF THE FRONT, COOLER AIR WILL BE USHERED INTO THE AREA
FOR FRIDAY WITH HIGHS AROUND 5 TO 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS:
- NO SEVERE WEATHER EXPECTED
- BELOW NORMAL TEMPERATURES
- WELCOME RAINFALL LATE THIS WEEK
IN THE WAKE OF THE FRONT...EXPECT TEMPERATURES TO BE COOL INTO
THE WEEKEND. DAYTIME HIGHS WILL BE IN THE LOW TO MID 70S WHICH IS
TEN DEGREES BELOW NORMAL.
LONG RANGE ENSEMBLE PREDICTION SYSTEMS CONTINUE TO EXIT THE CLOSED
MID LEVEL CYCLONE SLOWLY NE SATURDAY. THE SOUTHERN EXTENT OF THE
TROWAL IS PROJECTED TO BE JUST N OF OUR CWA...HOWEVER TIMING THIS
FAR OUT CAN CERTAINLY CHANGE. CARRIED PCPN MENTION A LITTLE LONGER
THAN AFOREMENTIONED MODELS INDICATE. BUFR SOUNDINGS AND LLVL RH
PROGS ILLUSTRATE A SATURATED BOUNDARY LAYER...SO CLOUDS SHOULD
TAKE THE BETTER PART OF SATURDAY TO VACATE THE REGION...ESPECIALLY
THE MTNS. WOULD NOT RULE OUT A PERIOD OF DRIZZLE IN THE HIGHER
TERRAIN SAT MRNG. THERMODYNAMIC INSTABILITY IS NIL...SO REMOVED
THUNDER FROM THE FORECAST FOR THE UPCOMING WEEKEND. CONDITIONS
IMPROVE DAYS 6 AND 7 WITH THE ESTABLISHMENT OF ZONAL FLOW AND A
RETURN TO MORE SEASONAL TEMPERATURES.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
HIGH CLOUDS WILL SLOWLY CLEAR FROM NW TO SE THROUGH THE EARLY
MORNING HOURS. THESE HIGH CLOUDS WILL LIKELY PRECLUDE ANYTHING
WORSE THAN BRIEF MVFR VISIBILITIES OVERNIGHT FROM KLBE TO KAGC AND
ALL POINTS SOUTH. NORTH OF THAT LINE...CLEARING AND DECENT
RADIATION WILL MAKE THE CHANCES OF BRIEF MVFR VISIBILITIES A BIT
HIGHER. HOWEVER...GIVEN THE CONTINUED RATHER WIDE DEWPOINT
DEPRESSIONS AT KPIT AND KDUJ...AND LIGHT FOG MAY BE MORE DIFFICULT
TO MANAGE THERE. OTHERWISE...SUBSIDENCE AND DEW FORMATION SEEM
LIKELY TO SETTLE OUT DEWPOINTS BY A COUPLE DEGREES
OVERNIGHT...WHICH WILL MEAN AND FOG WORSE THAN MVFR IS LIKELY TO
BE EXTREMELY LOCALIZED AND LIKELY AROUND A RIVER (SUCH AS KHLG).
FRIES
.OUTLOOK...MONDAY NIGHT THROUGH SATURDAY...
VFR IS EXPECTED THROUGH WEDNESDAY BEFORE RESTRICTIONS ARE POSSIBLE
IN SHRA/TSRA THURSDAY THROUGH SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1107 PM CDT MON AUG 6 2012
.UPDATE...
UPDATED TO INCLUDE 06Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
OVERVIEW...ABOVE NORMAL TEMPS EXPECTED TOMORROW BEFORE SHOWERS AND
STORMS ON WEDNESDAY KICK START A COOLING TREND THAT WILL LAST THROUGH
THE WEEKEND. RAIN CHANCES ON THURSDAY AND FRIDAY ARE BASED ON TWO
INDEPENDENT FEATURES. INCREASED POPS DURING THIS TIME FRAME.
CERTAINLY A NON ZERO CHANCE OF PRECIP TONIGHT IN WESTERN WI AND IN
FAR SOUTHERN MN. A COUPLE RUNS OF THE HRRR AND THE RAP BOTH
HIGHLIGHT THESE AREAS WITH SHOWERS LATE THIS EVENING. SEEING THE
EFFECTS OF THE COLD FRONT STRETCHED OUT ACROSS NORTHERN MM.
GETTING NEAR SURFACE CONVERGENCE SHOWING UP IN THE MESO ANALYSIS
BUT ALSO PRETTY OBVIOUS JUST BASED ON THE LOW LEVEL FLOW. NICE
BAND OF CUMULUS AND EVENED EMBEDDED SHOWERS VISIBLE THIS
AFTERNOON. SECONDLY...SUBTLE SHORTWAVE ENERGY IN THE EASTERN
DAKOTAS ALSO DROPPING SOUTH THIS AFTERNOON. NOT MUCH BEING
REFLECTED IN THE SHORT TERM HEIGHT/VORTICITY FIELDS...BUT
DEFINITELY SOMETHING APPARENT ON THE WATER VAPOR. IN
GENERALLY...TRIMMED THE POPS BACK TONIGHT. POP VALUES WERE ALREADY
LOW...IN THE 20-30%...BY LIMITED THE AREAL EXTEND OF THE POPS
COMPARED TO THE PREVIOUS FORECAST. THINK A VAST MAJORITY OF THE
FORECAST AREA REMAINS DRY EVEN WITH THE WEAK FRONTAL PASSAGE.
WONDERING IF THE HIGH DEWPOINT BIAS OFF THE RAP IS PLAYING INTO
THE EXTRA PRECIP TONIGHT.
REALLY CAN NOT SEE HOW MUCH DIFFERENT TOMORROW WILL BE COMPARED
TO TODAY IN TERMS OF TEMPERATURES. IT MIGHT BE A DEGREE OR TWO
COOLER THAN TODAY...BUT 70-80% OF THE GUIDANCE HAS FORECAST 2M
TEMPS AND 850MB TEMPS VERY SIMILAR TO WHAT WAS SEEN TODAY. STILL
LOOKS GOOD FOR AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS ON
WEDNESDAY WITH SHORTWAVE ROTATING AROUND THE RIDGE OVER THE NEXT
36-48HRS. SHEAR IS MARGINAL WITH RELATIVELY WEAK MID LEVEL
FLOW...BUT FORCING AND INSTABILITY SHOULD NOT BE A PROBLEM...SO
LIKELY POPS ARE NOT A STRETCH AT THIS POINT. WE BLEED THE POPS
INTO THURSDAY DUE TO THE UPPER LOW DROPPING SOUTH OUT OF THE
INTERIOR OF CANADA...NOW IN NORTH CENTRAL CANADA BETWEEN 70-75
NORTH. THIS SYSTEM HAS PROBABLY TRENDED A LITTLE BIT SLOWER AND
STRONGER WITH TIME OVER THE LAST COUPLE DAYS. THERE IS NOT MUCH
RECOVERY IN TERMS OF INSTABILITY...BUT COOL TEMPS ALOFT SUGGESTS
SHOWERY ACTIVITY WITH EMBEDDED THUNDER. COOLED TEMPS ON
THURSDAY...MIGHT BE HARD TO GET MUCH ABOVE 75 IN SOME LOCATIONS IN
CENTRAL MN AND WI WITH CLOUD COVER AND SHOWERS.
&&
.AVIATION.../06Z TAF ISSUANCE/
VFR CONDS TO PREVAIL THROUGHOUT THE 07/06Z TAF SET /EXCEPT FOR
POSSIBLE PRE-DAWN GROUND FOG ISSUES AT THE WI TAF SITES IN THE
MORNING/. A COLD FRONT WILL DROP THROUGH THE REGION OVERNIGHT.
VERY LITTLE CONVECTIVE ACTIVITY ALONG THE LINE EXCEPT ALONG ITS
ERN FRINGES IN THE ARROWHEAD REGION WHICH MAY DROP INTO NWRN WI.
RADAR IMAGERY SHOWS VERY LITTLE YET THERE IS A WEAK UPPER LEVEL
DISTURBANCE MOVING IN CONJUNCTION WITH THE FNT THAT MAY BE ENOUGH
TO PRODUCE ISOLD SHWRS OVER NWRN INTO CENTRAL WI...BUT CHCS ARE
TOO LOW FOR ITS INCLUSION...ESP WITH THE DRY LOWER-MIDDLE LAYERS
DEPICTED ON MODEL SOUNDINGS. THUS...HAVE KEPT THE TAFS DRY.
COMPACT LOW LEVEL MOISTURE UNDERNEATH THE NIGHTLY INVERSION OVER
WI MAY ALSO PRODUCE PRE-DAWN GROUND FOG...WITH KEAU
CLIMATOLOGICALLY FAVORABLE. AFTER DAWN...PLENTY OF SUNSHINE WITH
SHIFTING WINDS. HIGH CLOUDS INCRS LATE IN THE DAY THROUGH TMRW
EVENING AHEAD OF A STRONGER UPPER LEVEL DISTURBANCE MOVG TWD THE
REGION. POPS INCRS AFTER THE 06Z TIMEFRAME SO NO POPS NEEDED AT
THE TAIL END OF THIS TAF SET.
MSP...VFR CONDS THROUGHOUT. HIGH CLOUDS INCRS LATE IN THE DAY THRU
TMRW NIGHT AS HIGH PRES DEPARTS AND AN UPPER LEVEL DISTURBANCE
APPROACHES. WILL SEE CIGS IN THE 10-15 KFT RANGE BY TMRW EVENING
INTO TMRW NIGHT. CHCS FOR PRECIP STILL LESS THAN 20 PERCENT
THROUGH 12Z WED SO NO POPS INCLUDED AT THIS POINT. WINDS LGT/VRBL
OVERNIGHT THEN LESS THAN 10 KT FROM MAINLY THE N...ALTHOUGH THE
DIRECTIONAL FORECAST WILL BE A BIT TRICKY WITH THE FRONT PUSHING
THROUGH TNGT FOLLOWED BY HIGH PRESSURE SCOOTING ACROSS THE REGION.
OUTLOOK...
.WEDNESDAY...VFR WITH MVFR/TSRA POSSIBLE. WINDS SE AT 5-10 KTS.
.THURSDAY...MVFR CLOUDS AND SHRA DURING THE DAY...BECOMING VFR
OVERNIGHT. WINDS N AT 10G15 KTS.
.FRIDAY...VFR. WINDS E 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC
AREA FORECAST DISCUSSION
NWS JACKSON MS
1010 AM CDT TUE AUG 7 2012
.UPDATE...CLEAR TO PARTLY CLOUDY SKIES PREVAIL ACROSS MOST OF THE
ARKLAMISS THIS MORNING...BUT THERE ARE A FEW SHOWERS OVER CATAHOULA
AND CONCORDIA PARISH. THESE SHOWERS WILL CONTINUE TO DIMINISH
THROUGH THE MORNING HOURS. DRIER AIR BUILDING IN FROM A HIGH
CENTERED TO THE NORTHWEST WILL RESULT IN MAINLY JUST ISOLATED
THUNDERSTORM COVERAGE THIS AFTERNOON WITH THE BEST COVERAGE MAINLY
ALONG AND SOUTH OF I-20. OUR LOCAL WRF MODEL AND THE HRRR MODEL ALSO
SUGGEST THIS. MADE SOME SLIGHT CHANGES TO THE POP/WEATHER THIS
AFTERNOON...BUT OTHER THAN THAT THE CURRENT FORECAST LOOKS ON TRACK
AND NO UPDATES ARE NEEDED AT THIS TIME./15/
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...WITH MANY LOCATIONS
SEEING DECENT RAINFALL YESTERDAY...WE HAVE HAD TO CONTEND WITH FOG
THIS MORNING. LOCAL OBSERVATIONS SHOWING VISIBILITIES REDUCED IN
SOME PLACES TO 1/2-1/4 MILES...ESPECIALLY ALONG AND EAST OF I-55.
WILL CONTINUE TO MENTION PATCHY FOG THROUGH ABOUT 13-14Z BUT INCLUDE
MENTION OF DENSE FOG IN THE EAST AND SOUTH. VISIBILITIES ARE GOING
UP AND DOWN BUT WILL CONTINUE TO MONITOR IF AN ADVISORY IS NEEDED
THIS MORNING.
DRIER AIR HAS MOVED IN ALOFT ACROSS THE REGION AND THIS IS EVIDENT
IN A REDUCTION IN THE OVERALL PW VALUE PER THE 00Z KJAN SOUNDING.
DEWPOINTS THIS MORNING ARE RUNNING ABOUT 2-4 DEGREES LOWER THAN 24
HOURS AGO. IN ADDITION...THE UPPER TROUGH IS FORECAST TO BE TO OUR
EAST WITH NORTHWEST FLOW ALOFT OVER THE REGION. ALL OF THIS WILL
COMBINE FOR MORE OF A LACK OF STORM ACTIVITY TODAY. THE AREA WHERE
THE BETTER CHANCE WILL BE IS SOUTH OF I-20 WHERE ISOLATED COVERAGE
IS EXPECTED AT MOST AND THIS MAY EVEN STRUGGLE WITH THE DRIER AIR IN
PLACE. HIGHS TODAY ONCE AGAIN SHOULD REACH INTO THE MID
90S...ESPECIALLY IN THE DELTA WHERE RAINFALL REMAINS SCARCE AND
DRIER AIR SHOULD HELP CONDITIONS WARM UP. OVERNIGHT LOWS WILL BE IN
THE LOWER 70S AND EVEN SOME UPPER 60S.
FOR WEDNESDAY...THE UPPER PATTERN WILL REMAIN SIMILAR WITH THE
TROUGH TO THE EAST AND THE MAIN UPPER RIDGE TO THE WEST. WE MAY SEE
A LITTLE MORE IN THE WAY OF DAYTIME SHOWERS AND
THUNDERSTORMS...ESPECIALLY ACROSS THE SOUTH AS TEMPERATURES WARM
INTO THE MID 90S ONCE AGAIN. THE DRIEST AIRMASS WILL ONCE AGAIN BE
LOCATED IN THE DELTA...LIMITING ANY RAIN CHANCES THERE WHERE THE
MOIST AIR WILL BE ACROSS THE FAR SOUTHERN PORTIONS OF THE PINE BELT.
ANY DAYTIME ACTIVITY WILL DIMINISH WITH SUNSET...LEAVING RELATIVELY
COOL NIGHT AS COMPARED TO RECENT WEEKS. /28/
.LONG TERM...THURSDAY THROUGH MONDAY...NOT MUCH CHANGE FROM THE PREV
LONG TERM AS MED RANGE GUID CONTINUE TO SUPPORT A SIMILAR PATTERN
FOR LATE WEEK AND THE WEEKEND. ACTUALLY...MODELS ARE IN BETTER
AGREEMENT THAN LAST NIGHT...THUS THE EVOLUTION OF PRIMARY ELEMENTS
CONTAIN HIGHER CONFIDENCE. ONE OF THE MAIN FEATURES OF INTEREST IS A
LATE SUMMER COOL FRONT THAT NOW LOOKS TO PUSH WELL INTO THE CWA IF
NOT THROUGH THE CWA BY EARLY SATURDAY.
NW FLOW PATTERN WILL BE IN PLACE THROUGH THE WEEKEND WITH A FEW
DISTINCT S/WV`S DRIVING THE MAIN WEATHER FEATURES. FIRST OFF ON
THU-FRI THE CWA WILL BE LOCATED SOUTH OF THE SFC FRONT AND WITHIN
THE LOW LEVEL THERMAL AXIS. THIS WILL SUPPORT EASILY MID 90 DEGREE
TEMPS THU AFTERNOON. I WOULD LIKE TO WARM TEMPS MORE...BUT THERE ARE
A FEW THINGS THAT THE MODELS ARE SHOWING THAT IS HOLDING ME BACK
FROM BEING MORE AGGRESSIVE. FOR FRI...TEMPS WERE WARMED SOME 2-4
DEGREES TO KEEP IN LINE WITH WARMER READINGS JUST AHEAD OF THE SFC
FRONT. AS FOR PRECIP/WX...THE FIRST S/WV LOOKS TO IMPACT THE CWA
LATE THU AFTERNOON AND MOST LIKELY THU NGT. THERE LOOKS TO BE SOME
LINGERING MID LEVEL DRY AIR OVER THE NW HALF OF THE CWA ON THU AND
IT WILL LIKELY TAKE MOST OF THE DAY FOR THE APPROACHING S/WV TO
PROVIDE SUFFICIENT LIFT TO ERODE THAT LAYER...THUS BETTER POPS ARE
FOCUSED THU EVE/NGT WHICH IS INLINE WITH LATEST GFS. QUICKLY ON THE
HEALS OF THE FIRST S/WV WILL BE A MORE POTENT WAVE THAT IS MORE
PHASED WITH THE LONG WAVE TROUGH AXIS THAT WILL STRETCH FROM THE
GREAT LAKES DOWN THROUGH THE LOWER MS VALLEY. THIS WILL PROMOTE
ADDITIONAL STORM DEVELOPMENT FRI...ESPECIALLY ACROSS THE SOUTH HALF
WHERE DEEPEST MOISTURE LOOKS TO EXIST.
THE ABOVE MENTIONED LONG WAVE TROUGH WILL BE THE DRIVING FORCE THAT
LOOKS TO PUSH A COOL FRONT WELL INTO THE CWA FOR LATE FRI NGT/SAT.
DON`T EXPECT "COOL" AIR...BUT THE CHANGE IN AIRMASS SHOULD KNOCK THE
EDGE OFF THE HEAT AS HIGH WILL BE MORE FROM THE UPPER 80S TO LOWER
90S INSTEAD OF THE MID 90S. ADDITIONALLY...DRIER AIR WILL MOVE IN
AND SFC DEWPTS LOOK TO FALL WELL INTO THE 60S. THIS WILL ALSO
SUPPORT SLIGHTLY COOLER NIGHTS WITH LOWS RANGING FROM 65-70 FROM
SAT-MON MORNINGS. OVERALL...THIS SHOULD BE SOME 3-5 DEGREES BELOW
AVG ALONG WITH LESS HUMIDITY. QUITE NICE FOR EARLY AUG. /CME
&&
.AVIATION...PATCHY SUB-VFR CONDITIONS AROUND EARLY THIS MORNING DUE
TO FOG HAVE LIFTED...ALTHOUGH SOME CLOUDS AND A FEW SHOWERS ARE
OCCURRING ACROSS PORTIONS OF NE LA BRUSHING THE SOUTHWEST EDGE OF
THE FORECAST AREA. EXPECTING SCATTERED CLOUDS TO DEVELOP THROUGHOUT
THE DAY...BUT NEARLY ALL CEILINGS SHOULD REMAIN ABOVE 3 KFT.
THUNDERSTORM COVERAGE SHOULD BE MUCH LESS THAN YESTERDAY...ALTHOUGH
THERE WILL STILL BE ISOLATED SPOTS OF ACTIVITY AROUND THIS AFTERNOON
ALONG AND SOUTH OF INTERSTATE TWENTY. WINDS WILL GENERALLY TEND TO
BE FROM THE NORTH FROM MIDDAY THROUGH EARLY EVENING AT 5 TO 10 MPH.
FOR TONIGHT THE POTENTIAL FOR PATCHY FOG SHOULD BE LOWER THAN WHAT
WAS THE CASE THIS MORNING. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 94 70 96 71 / 14 13 12 17
MERIDIAN 95 70 96 71 / 13 13 12 19
VICKSBURG 95 68 95 69 / 13 13 12 13
HATTIESBURG 96 73 97 74 / 17 19 40 24
NATCHEZ 93 71 93 73 / 15 14 29 17
GREENVILLE 95 69 96 71 / 8 6 9 12
GREENWOOD 95 69 95 70 / 10 6 11 11
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
28/CME
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1249 PM CDT TUE AUG 7 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Have raised afternoon temperatures by a few degrees owing to
presence of h8 thermal ridge overhead, plenty of sun and a boundary
layer that is once again drying out and allowing for super-adiabatic
lapse rates to occur near the surface. Also bumped up pops over far
northeast KS and parts of far nw MO due to new convection which
sprouted over northeast KS since 1645Z. None of the short range
convective models are handling the convection over KS. Using the
overall LSX local WRF, HRRR and NAM20 model trends suggest
convection should have a difficult time moving too far owing to a
very weak steering flow and relatively stable downstream airmass.
MJ
&&
.PREV DISCUSSION...
/337 AM CDT Tue Aug 7 2012/
Today through Thursday...
The main forecast challenge in the short term is precipitation
chances for this afternoon through Wednesday across the region. Both
the NAM and GFS break out convection this afternoon across eastern
Nebraska, where a subtle surface boundary creates minor lift for
initiation. The front will likely become more diffuse as it travels
southward, which will combine with an increasing capping inversion
to make precipitation unlikely in our area through late this
evening. However; in case thunderstorms that do develop track into
our far northwest this evening, edged some slight chances into our
far northwest before 06z Wednesday.
Currently, the highest probability for rainfall looks to be across
our far west after 06z Wednesday. A decent low level jet develops
across central Kansas and eastern Nebraska around midnight, while a
slight southeasterly turn to the low level wind field brings a bit
more moisture into play across the region. These ingredients could
support thunderstorm development or the enhancement of ongoing
convection in southeast Nebraska and northeast Kansas, which could
form an MCS that tracks through northwest Missouri early Wednesday
morning. A shortwave trough will approach the region around daybreak
on Wednesday, turning steering winds to the west southwest and
pushing any weakening activity across southern Iowa and far northern
Missouri, likely exiting the region around mid morning. As a result,
there will be a marginal severe weather threat across our northwest
early Wednesday morning if a well-formed MCS can develop and move
through the region.
By Wednesday afternoon, the shortwave will drop southeastward
through northern Missouri, possibly supporting broadly scattered
showers and thunderstorms across the CWA during the daytime. Without
appreciable surface focus for initiation and the mixing of low-level
moisture during the afternoon, the probability of precipitation
remains somewhat low, but is worth mentioning with decent midlevel
forcing. Models are a bit inconsistent on the speed of the wave and
its trajectory, but precipitation chances should taper off Wednesday
night from west to east, ending Thursday morning.
Temperatures during the period will depend on the coverage of clouds
and precipitation, but should be warmest today with mixing of mid
20s C 850 temperatures and only scattered midlevel clouds, then
cooler Wednesday and Thursday as the trough over the east deepens
and temperatures aloft cool.
Laflin
Medium Range (Friday - Monday)
The pattern during the extended forecast seems pretty slow to evolve
leaving the region in prolonged northwest flow. this should keep
temperatures at or possibly even below normal for the period. While
models show some precipitation chances over the weekend due to an
advancing shortwave, latest ECMWF shows our chances diminishing.
With atmospheric moisture limited, low to no pops is probably the
right choice. For now will go with the 15-20 pops the model blend
init gave, but wouldn`t be surprised to see us go dry for the
weekend over the next few days if the trend continues.
Bailey
&&
.FIRE WEATHER...
Much like Monday afternoon, very dry conditions are expected again
Tuesday afternoon as winds turn to the south at 5 to 10 knots.
Relative humidity values will once again fall to around 20% but
light winds will preclude widespread red flag conditions. However,
given the severity of the drought conditions, any increase in winds
will lead to substantially higher fire danger threats. Will continue
to issue an SPS for the elevated fire danger threat.
MJ
&&
.AVIATION...
For the 18z TAFs, expect VFR conditions overall during this forecast
period. Short range models not handling the current upstream
convection very well. However, weak steering flow suggests this
activity will be slow moving and pass west of KSTJ and likely not
reach the KMCI/KMKC terminals. Owing to much uncertainty in timing
and lack of confidence later in the forecast will use VCTS to
indicate potential of nearby storms and await better modeling or
established radar trends and amend if necessary. Better bet for
convection will most likely occur after 18z Wed.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
934 PM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS OUR AREA BY EARLY THIS
EVENING...WITH SCATTERED SHOWERS AND THUNDERSTORMS ACCOMPANYING ITS
PASSAGE. MAINLY DRY WEATHER WILL THEN FOLLOW THE FRONT TONIGHT...
BEFORE LOW PRESSURE LIFTS NORTHEAST FROM THE OHIO VALLEY THURSDAY
AND FRIDAY AND BRINGS INCREASINGLY UNSETTLED CONDITIONS.
&&
.NEAR TERM /THROUGH THURSDAY/...
THROUGH THIS EVENING...SHOWERS AND THUNDERSTORMS HAVE EXITED THE
REGION...LEAVING WESTERN NEW YORK DRY. RADAR DOES SHOW SOME
LINGERING SHOWERS ACROSS SOUTHWESTERN ONTARIO...BUT THESE ARE
LIKELY TO CONTINUE TO SLIDE TO THE NORTHEAST. CONSENSUS QPF AMONG
THE PAST TWO RUNS OF THE NAM/GFS/RGEM SHOW MODEST AMOUNTS NEAR AND
SOUTH OF A STALLED FRONTAL BOUNDARY IN SOUTHERN PORTIONS OF THE
CWA...BUT FEEL THE LARGELY DRY HRRR IS MORE LIKELY TO VERIFY.
OTHERWISE...THERE IS A POTENTIAL FOR FOG TO FORM TONIGHT...THOUGH
THIS LARGELY DEPENDS ON HOW QUICKLY CLOUDS ASSOCIATED WITH THE
SYSTEM ACROSS MICHIGAN SPREAD INTO THE REGION. TEMPERATURE-DEW
POINT SPREADS ARE NARROW IN AREAS WHERE SHOWERS FELL TODAY...AND
IN THE VALLEYS...SO WE COULD SEE FOG START TO DEVELOP LATE THIS
EVENING IN THESE SPOTS. THEN FOG WILL VARY BASED ON CLOUD
COVER...AS A BROKEN LAYER OF MID-HIGH CLOUDS ENTERS FROM WEST TO EAST.
ON THURSDAY...CLOUDS WILL CONTINUE TO INCREASE AND THICKEN ACROSS
THE AREA FROM SOUTHWEST TO NORTHEAST AS UPPER TROUGHING TAKES
SHAPE ACROSS THE GREAT LAKES...AND AN ATTENDANT SURFACE LOW
DEVELOPS AND LIFTS NORTHEAST ACROSS THE OHIO VALLEY. WITH DIURNAL
HEATING...THE FRONTAL BOUNDARY STALLED OUT JUST TO OUR SOUTH MAY
BECOME THE FOCUS FOR ANOTHER ROUND OF SCATTERED CONVECTION ACROSS
THE SOUTHERN TIER AND FINGER LAKES DURING THE AFTERNOON...BEFORE
THE MAIN SURFACE WAVE DRAWS CLOSE ENOUGH TO BRING INCREASING
SHOWER/THUNDERSTORM CHANCES TO THE REST OF THE REGION LATER IN THE
DAY. WILL CONTINUE TO INDICATE A NORTHEAST-SOUTHWEST GRADIENT IN
PRECIP CHANCES ACROSS THE REGION TOMORROW AFTERNOON...RANGING FROM
SLIGHT CHANCE/LOW CHANCE ACROSS THE SAINT LAWRENCE VALLEY AND
NORTH COUNTRY...TO HIGH CHANCE ACROSS THE SOUTHERN TIER AND FAR
WESTERN NEW YORK. WITH THE BEST INSTABILITY REMAINING ALONG AND
SOUTH OF THE FRONT AND ANY STRONGER WIND FIELDS ALOFT REMAINING TO
ITS NORTH...AT THIS POINT OUR SEVERE WEATHER POTENTIAL FOR
TOMORROW AFTERNOON LOOKS TO BE RELATIVELY LOW.
AS FOR TEMPERATURES...READINGS WILL AGAIN BE A LITTLE MILDER TONIGHT
THAN LAST NIGHT...WITH LOWS RANGING FROM THE UPPER 50S/NEAR 60
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND NORTH COUNTRY TO
THE MID 60S ACROSS THE LAKE PLAINS. WITH 850 MB TEMPS OF +14C TO
+16C AND INCREASING CLOUD COVER/PRECIP CHANCES THEN EXPECTED ON
THURSDAY...DAYTIME HIGHS SHOULD RANGE FROM THE LOWER TO MID 80S IN
MOST LOCATIONS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
MUCH NEEDED BENEFICIAL RAINS CONTINUING TO LOOK PROMISING DURING THE
THURSDAY NIGHT THROUGH FRIDAY NIGHT TIME FRAME...AS POTENT UPPER
LEVEL LOW DROPS THROUGH THE GREAT LAKES. NAM/CANADIAN/GFS ALL ON
BOARD IN CONTINUING TO DEVELOP INCREASING RAIN AREA...ALONG WITH
SOME EMBEDDED STRONGER CONVECTION WITH THE INCREASING MID LEVEL
FRONTOGENESIS AND SUBSTANTIAL HEIGHT FALLS TAKING PLACE.
PRECIPITATION PATTERN LOOKS TO BECOME EVEN MORE FOCUSED LATE
THURSDAY NIGHT AND FRIDAY. THE LOW/MID LEVEL BAROCLINIC ZONE
EXTENDING ACROSS NEW YORK STATE WILL UNDERGO SIGNIFICANT
FRONTOGENESIS AND DEEPEN IN RESPONSE TO INCREASING UPPER LEVEL
DIVERGENCE AND INTENSE LARGE SCALE ASCENT JUST AHEAD OF THE PV
ANOMALY...ALLOWING RAIN/EMBEDDED THUNDER TO INCREASE IN
COVERAGE/INTENSITY. PLACEMENT OF HEAVIEST PRECIPITATION AXIS WILL BE
A TOUGH CALL WITH STILL SOME MODEL DISCREPANCIES IN THE EXACT TRACK
OF THE UPPER LEVEL LOW AND SUBSEQUENT SURFACE WAVE...AS WELL AS A
MODEL AGREEMENT OF THE PRESENCE OF A SHARP DRY SLOT NOSING INTO A
PORTION OF THE AREA. PRECIPITABLE WATER VALUES ACROSS THE ENTIRE
AREA WILL BE RUNNING IN THE 1.5 TO 1.75 INCH RANGE. EXPECTATIONS ARE
THAT A GENERAL WIDESPREAD 0.75 TO 1.25 INCHES OF RAIN WILL
OCCUR...WITH HEAVIER AMOUNTS NEARING 2 INCHES VERY POSSIBLE ACROSS
EASTERN SECTIONS OF THE AREA WHERE MODELS DO NOT PLACE ANY
SIGNIFICANT DRY SLOTTING.
THE STEADIEST PRECIPITATION SHOULD DROP OF FRIDAY NIGHT AND SATURDAY
AS DEEP DRY SLOT WORKS INTO THE AREA BEHIND THE LOW AS IT PUSHES
INTO ONTARIO. HOWEVER...WRAP AROUND MOISTURE BEGINS TO WORK INTO
WESTERN SECTIONS DURING THE DAY SATURDAY...EVENTUALLY PUSHING
THROUGH EASTERN SECTIONS BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
HEIGHTS BEGIN TO RISE IN THE WAKE OF THE UPPER LOW FOR THE SECOND
HALF OF THE WEEKEND. A LINGERING CYCLONIC FLOW OVER EASTERN SECTIONS
OF THE AREA COULD TOUCH OFF A FEW SHOWERS...OTHERWISE THE OVERALL
TREND IS TO DRY THINGS OUT FROM WEST TO EAST. HEIGHTS CONTINUING TO
RISE THROUGH MID WEEK. FOR THE MOST PART EXPECT DRY WEATHER...
ALTHOUGH GLOBAL MODELS SUGGESTING A COUPLE OF WEAK SHORT WAVES
CROSSING THE REGION IN THE NORTHWEST FLOW ALOFT. HOWEVER...THESE
MODELS DIFFER IN INTENSITY AND TRACK OF THE INDIVIDUAL WAVE WAND
CONFIDENCE IS LOW THAT MUCH ACTIVITY WILL BE GENERATED...OTHER THAN
SOME SPOTTY DIURNALLY DRIVEN CONVECTION.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
THE MAIN AVIATION CONCERN TONIGHT IS THE POTENTIAL FOR FOG. THIS
SHOULD BE PATCHY IN NATURE...DEPENDING ON HOW MUCH RAIN FELL TODAY
AND HOW LONG LOCATIONS REMAIN CLEAR BEFORE MID AND HIGH CLOUDS
MOVE IN LATE TONIGHT. JHW HAS THE BEST CHANCE FOR FOG...THOUGH IT
CANNOT BE RULED OUT AT ANY LOCATION. FOG COULD BE LOCALLY
DENSE...BUT VSBY WILL LIKELY IMPROVE BEFORE 12Z AS CLOUDS MOVE IN.
EXPECT THURSDAY TO START OFF MAINLY VFR...WITH AN INCREASING
CHANCE FOR SHOWERS OR THUNDERSTORMS DURING THE AFTERNOON HOURS.
AREAL COVERAGE SHOULD BE SCATTERED IN NATURE...SO FOR NOW WILL
JUST INTRODUCE A VCSH TO THE TAFS. SHOWERS AND THUNDERSTORMS MAY
BRING BRIEF PERIODS OF IFR OR LOWER CONDITIONS.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...IFR/MVFR IN RAIN WITH SCATTERED
THUNDERSTORMS.
SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
SUNDAY...MAINLY VFR.
MONDAY...VFR.
&&
.MARINE...
MAINLY DRY WEATHER WILL THEN FOLLOW THE FRONT TONIGHT...BEFORE LOW
PRESSURE LIFTS NORTHEAST FROM THE OHIO VALLEY THURSDAY AND FRIDAY
AND BRINGS INCREASINGLY UNSETTLED CONDITIONS...INCLUDING THE
THREAT OF SCATTERED THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...GENERALLY LIGHT TO MODEST WINDS TO
CONTINUE THROUGH THURSDAY...WITH WAVES REMAINING UNDER 2 FEET. AFTER
THAT TIME...A STRENGTHENING NORTH TO NORTHEASTERLY FLOW WILL BRING A
RISK OF ADVISORY LEVEL WINDS AND WAVES TO WESTERN LAKE ONTARIO BY
FRIDAY MORNING.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...APFFEL/JJR
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...APFFEL
MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
721 PM EDT WED AUG 8 2012
.SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE
EVENING. ONLY WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED THURSDAY WITH BETTER CHANCES EXPECTED FRIDAY. A COLD FRONT
WILL ALLOW THE CHANCE OF STORMS TO CONTINUE ON SATURDAY. HIGH
PRESSURE WILL BUILD INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 6:00 PM WEDNESDAY...HAVE FIRED OUT A QUICK UPDATE TO GO WITH
CATEGORICAL POPS FOR NORTHWESTERN COUNTIES AS CONVECTION APPEARS TO
BE ORGANIZING. HRRR HAS THE ACTIVITY CAPTURED WELL AND MAINTAINS IT
FOR SEVERAL HOURS. DAYTIME HEATING HAS ALLOWED THE TEMPERATURES TO
RISE TO THE UPPER 80S IN THESE AREAS PROVIDING AMPLE SURFACE BASED
INSTABILITY. HRRR/1800 UTC GFS AND NAM SHOW THIS WILL BE ALL THE
ACTIVITY AND THEREFORE REMOVED POPS FOR THE REMAINDER OF THE AREA
AFTER AROUND 0400 UTC.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...THE NEXT H5 TROUGH WILL DEVELOP ACROSS THE
MS VALLEY THU AS AN UPPER LOW DIVES SOUTH FROM THE WESTERN GREAT
LAKES REGION. THE RESULT WILL BE A HIGHLY AMPLIFIED/ANOMALOUS TROUGH
ALOFT OVER THE EASTERN UNITED STATES BY FRIDAY. THE TROUGH WILL PUSH
A COLD FRONT TOWARD THE FORECAST AREA LATE FRIDAY. THE PRECIPITABLE
WATER WILL ALSO INCREASE TO 2+INCHES FRIDAY AHEAD OF THE FRONT ALONG
WITH SUFFICIENT INSTABILITY THE BETTER BET FOR TSTMS DURING THE
SHORT TERM PERIOD WILL BE FRIDAY. CURRENTLY THE FORECAST AREA IS IN
A SLIGHT RISK FOR SEVERE TSTMS FRIDAY...BUT ULTIMATELY IT MAY DEPEND
ON THE AMOUNT OF CLOUD COVER WHICH COULD IMPEDE DESTABILIZATION.
OTHERWISE...FAVORED A BLEND OF MAV/MET NUMBERS EACH PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...IN A PATTERN MORE COMMONLY SEEN IN NOVEMBER
THAN MID-AUGUST...A HIGHLY ANOMALOUS 500MB TROUGH SPINS ACROSS THE
GREAT LAKES BEFORE ROTATING OFF TO THE NORTHEAST DURING THE EARLY
PART OF THE WEEK. AS THIS TROUGH SLOWLY SPINS AWAY...IT DRAGS A COLD
FRONT ACROSS THE AREA. GUIDANCE IN DECENT AGREEMENT ON TIMING OF
THIS FRONT...AND EXPECT FROPA TO OCCUR VERY EARLY SUNDAY. MOST
SIGNIFICANT WEATHER OF THE EXTENDED WILL OCCUR SATURDAY AS FRONT
PUSHES ACROSS THE AREA...DISPLACING THE WARM SECTOR AIRMASS. ATTM
SPC HAS NO PORTION OF OUR REGION OUTLOOKED IN DAY 4...BUT WOULD NOT
BE SURPRISED IF A SLIGHT RISK OR SEE TEXT IS INTRODUCED WITH LATER
UPDATES AS FRONT WORKS INTO A MODERATELY UNSTABLE AIRMASS WITH
DECENT NEARLY UNIDIRECTIONAL SHEAR AND HIGH PWATS.
ADDITIONALLY...GFS/EURO SHOW STRONG PVA ASSOCIATED WITH A VORT LOBE
ALONG THE FRONT AND DIFFLUENCE IN THE RIGHT ENTRANCE REGION TO A
90KT 300MB JET. ALL THESE TOGETHER SUGGEST SCATTERED TO WIDESPREAD
THUNDERSTORMS SATURDAY...WITH THE POTENTIAL FOR ISOLATED DAMAGING
WIND GUSTS. THE LIMITING FACTOR MAY BE INCREASED CLOUD COVER FROM
CONVECTIVE DEBRIS FRIDAY...BUT THIS IS STILL YET TO BE SEEN. WILL
KEEP INHERITED LIKELY POP SATURDAY...WANING TO SCHC BY SUNDAY
MORNING AS FRONT MOVES OFFSHORE. TEMPS SATURDAY WILL BE RIGHT AROUND
CLIMO...90/70.
DRIER AIR BEHIND THE FRONT COMBINED WITH SLIGHTLY INCREASED 500MB
HEIGHTS WILL CAUSE A SIGNIFICANT DECREASE IN TSTM CHANCES SUN-TUE.
STILL...WITH TEMPS AROUND 90 AND SLIGHTLY ENHANCED LAPSE RATES DUE
TO BROAD EAST-COAST TROUGHING...ANY DAY COULD FEATURE ISOLATED
DIURNAL CONVECTION. WILL KEEP POP BELOW MENTIONABLE SUN/MON BEFORE
MOISTURE RETURN INCREASES WITH RETURN OF BERMUDA HIGH TUE/WED. TEMPS
THROUGH THE WEEK WILL BE NEAR NORMAL FOR MID AUGUST.
&&
.AVIATION /00Z WEDNESDAY THROUGH MONDAY/...
AS OF 00Z...VFR EXPECTED THROUGH VALID PERIOD...WITH EXCEPTION OF
ANTICIPATED MVFR/POSSIBLE IFR/ FOG LATE OVERNIGHT INTO THE EARLY
MORNING HOURS.
CURRENT RADAR IMAGERY DEPICTS AN AREA OF TSRA/SHRA MOVING INTO THE
AREA...WHICH WILL IMPACT THE INLAND TERMINALS OVER THE NEXT
COUPLE OF HOURS. FOR THE REST OF THE OVERNIGHT HOURS...LIGHT SOUTH
WINDS WILL PREVAIL WITH FEW/SCT LOW AND HIGH-LEVEL CLOUDS ACROSS
THE AREA. GIVEN RECENT RAINFALL WITH ANTICIPATED LIGHT WINDS AND
ONLY FEW/SCT HIGH LEVEL CLOUDS...MODEL GUIDANCE AGREES WITH
POTENTIAL FOR MVFR AT ALL SITES OVERNIGHT...WITH POSSIBLE
IFR...ESPECIALLY INLAND. AFTER DAYBREAK...ANY LINGERING FOG WILL
QUICKLY DISSIPATE ALLOWING FOR VFR TO PREVAIL. AS TROPICAL AIRMASS
CONTINUES...CANNOT RULE OUT ISOLATED SHOWERS AND A POSSIBLE
THUNDERSTORM THROUGHOUT THE DAY. ATTM...HAVE INTRODUCED VCSH INTO
CURRENT FCST. SOUTHWEST WINDS WILL BACK TO THE SOUTH BY THE
AFTERNOON HOURS AND PREVAIL WITH SUSTAINED WINDS AOB 12 KTS.
ANTICIPATE ANY SHRA/CONVECTION TO TAPER OFF INTO THE EVENING HOURS
WITH WINDS BECOMING LIGHT.
EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:00 PM WEDNESDAY...NO CHANGES TO COASTAL WATERS FORECAST WITH
THE EVENING UPDATE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...LIGHT WESTERLY FLOW THURSDAY MORNING WILL
BACK TO A SOUTHERLY DIRECTION DURING THE DAY AND INCREASE INTO THE
10-15 KT RANGE. SOUTH TO SOUTHWEST FLOW WILL PREVAIL THURSDAY NIGHT
AND LINGER AROUND 15 KT FRIDAY. SPEEDS COULD REACH 15-20 KT FRIDAY
NIGHT AHEAD OF A COLD FRONT. THE SOUTH TO SOUTHWEST FETCH WILL ALLOW
SEAS TO BUILD TO EXERCISE CAUTION LEVELS DURING THE PERIOD...AND
WILL BE HIGHEST DURING FRIDAY NIGHT
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 3 PM WEDNESDAY...SW FLOW THROUGH THE PERIOD...BUT WILL BE
STRONGEST SATURDAY AS COLD FRONT APPROACHES FROM THE WEST. AS THIS
FRONT WORKS TOWARDS THE COAST...PRESSURE GRADIENT TIGHTENS...AND
WINDS WILL BE AROUND 15 KTS SATURDAY. GRADIENT WILL EASE AS FRONT
MOVES TO THE WATERS AND DISSIPATES BY EARLY SUNDAY...BECOMING 10 KTS
OR LESS SUNDAY AND MONDAY...STILL FROM THE SW. A WEAK SE SWELL WILL
EXIST THROUGH THE EXTENDED...BUT SIGNIFICANT WAVE HEIGHTS WILL BE
DRIVEN ALMOST EXCLUSIVELY BY THE WIND. 3-5 FT SEAS SATURDAY WILL
DECREASE THROUGH SUNDAY...BECOMING 2-3 FT LATE SUNDAY AND MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...15
SHORT TERM...SRP
LONG TERM...JDW
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EDT TUE AUG 7 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL DRIFT EAST ACROSS THE CAROLINAS AND
SOUTHERN VIRGINIA TODAY AND TONIGHT...AND LIE ALONG THE COASTAL
PLAIN ON WEDNESDAY. ANOTHER UPPER LEVEL TROUGH WILL AFFECT OUR
REGION FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...
AREAS OF LIGHT TO MODERATE RAIN STRETCH FROM THE SOUTHERN PIEDMONT
TO THE NORTHERN COASTAL PLAIN THIS MORNING...ALONG A SHEARED OUT
VORTICITY AXIS NOTED IN WATER VAPOR AND RAP 500MB ANALYSIS. WHILE
ALL OF THE CWA OVERCAST...THE LOW STRATUS IS THICKEST OVER THE FROM
THE TRIANGLE WESTWARD TO THE TRIAD....AND VISIBLE SATELLITE IMAGERY
SHOWS A VEIL OF MID CLOUDS STREAMING ACROSS THE WESTERN HALF OF THE
STATE. THUS...EVEN AS THE STRATUS SLOWLY LIFTS THIS MORNING...SOME
AREAS MAY STRUGGLE TO GET OUT OF THE 70S...ESPECIALLY IN THOSE AREAS
WHERE RAIN FALLS THROUGH MIDDAY. SOME BREAKS IN CLOUD COVER ARE
BEGINNING TO SHOW OVER THE SOUTHERN COASTAL PLAIN...AND TEMPS COULD
REACH THE MID 80S FROM FAYETTEVILLE TO THE SOUTHEAST. WHILE
CONFIDENCE IN THE TEMP FORECAST IS LOW... HAVE ATTEMPTED TO ADJUST
TEMPS DOWNWARD OVER THE WESTERN PIEDMONT USING MET MOS AND NAM/GFS
RAW 2M TEMP FIELDS BASED...WHICH YIELDS VALUES ROUGHLY IN THE 79-85
RANGE.
REGARDING POPS...A WEAK UPPER LEVEL LOW AND ASSOCIATED VORT MAX OVER
AL/GA THIS MORNING WILL BE DRAWN NORTHWARD TODAY AHEAD OF AN UPPER
LEVEL TROUGH APPROACHING FROM THE MIDWEST. MEANWHILE.. A WEAK UPPER
JET OVER THE MID ATLANTIC STATES IS FORECAST TO BUILD BACK TO THE
SOUTHWEST ACROSS VA...WHICH SHOULD PROVIDE SOME RIGHT ENTRANCE
REGION LIFT AND ALSO HELP PRECIP EXPAND BACK TO THE NORTH OF THE
CURRENT PRECIP AXIS. MOST CAMS SUGGEST PRECIP WILL SHIFT NORTH
TOWARD ACROSS THE PIEDMONT THIS MORNING...THEN SHIFT EASTWARD TOWARD
THE COASTAL PLAIN LATER THIS AFTERNOON AND EVENING WITH THE SHEAR
AXIS. MOST OF THE WESTERN PIEDMONT SHOULD REMAIN RELATIVELY STABLE
AS COMPARED TO THE EASTERN PIEDMONT AND COASTAL PLAIN...WHERE
MODIFICATION OF THE 12Z KMHX RAOB SUGGEST 1000-1500 J/KG OF MLCAPE
IS POSSIBLE IF TEMPS CAN REACH THE MID 80S. DEEP LAYER SHEAR
FORECASTS CONTINUE TO BE BELOW 20KT...SO SEVERE POTENTIAL REMAINS
LOW AND WILL BE CONFINED TO STRONGER PULSE STORMS. HAVE MADE SOME
ADJUSTMENTS TO THE TIMING OF POPS THIS MORNING...BUT OVERALL THE
SHOWERS WILL BE NUMEROUS THIS AFTERNOON WITH SCATTERED STORMS AND
HEAVY RAIN MAINLY EAST.
FLASH FLOOD GUIDANCE HAS RECOVERED TO NORMAL VALUES FOR MOST AREAS
THIS MORNING. THE EXCEPTIONS APPEARS TO BE MAINLY RANDOLPH AND
STANLEY COUNTIES WHERE THE HEAVIEST RAIN FELL MONDAY. ONE TO TWO
INCHES IN AN HOUR OR TWO COULD CAUSE SOME FLOODING ISSUES IN THOSE
AREAS IF HEAVIER SHOWERS MATERIALIZE LATER TODAY. -SMITH
TONIGHT...BEST FOCUS FOR SHOWERS WILL BE ACROSS THE COASTAL PLAIN
THE FIRST HALF OF THE EVENING AS SHEAR AXIS DRIFTS EAST THOUGH
SHOULD SEE COVERAGE DECREASE BY MIDNIGHT AS AIR MASS STABILIZES AND
BEST LOW LEVEL MOISTURE TRANSPORT SHIFTS MORE TO THE IMMEDIATE COAST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT...WITH THE SHEAR AXIS CLOSER TO THE
COAST...EXPECT A RETURN TO MORE TYPICAL SUMMERTIME PATTERN OVER THE
PIEDMONT WITH RANDOM...DIURNALLY DRIVEN CONVECTION EXPECTED. SURFACE
PROJECTIONS SUGGEST A DEWPOINT GRADIENT BETWEEN THE TRIAD AND THE
TRIANGLE/FAY AREAS...SO EXPECT CONVECTION TO INITIATE ALONG THIS
FEATURE BY EARLY-MID AFTERNOON WITH CONVECTION DRIFTING EAST-SE.
THIS SUGGEST MORE COVERAGE IN THE SE VERSUS NW. PLAN TO HAVE POPS 30
PERCENT NW TO 50 PERCENT SE. PERIODS OF SUN PRIOR TO CONVECTION
INITIATION SHOULD LEAD TO AFTERNOON CLOSE TO NORMAL (UPPER 80S TO
AROUND 90). ANY CONVECTION WED EVENING SHOULD DIMINISH WITH LOSS OF
HEATING. PARTIAL CLEARING MAY ALLOW FOR THE DEVELOPMENT OF AREAS OF
FOG BY DAYBREAK THU. MIN TEMPS UPPER 60S TO LOWER 70S.-WSS
THURSDAY AND THURSDAY NIGHT:
BRIEF WESTERLY MID LEVEL FLOW IS EXPECTED TO AGAIN BACK TO
SOUTHWESTERLY ACROSS OUR AREA ON THURSDAY AS THE EAST COAST TROUGH
BEGINS TO DEEPEN AGAIN AS A STRONG S/W ALOFT DROPS
SOUTH/SOUTHEASTWARD OUT OF CANADA INTO THE UPPER MIDWEST AND GREAT
LAKES REGION. AT THE SURFACE MODELS INDICATE A SHARPENING
PIEDMONT/LEE SIDE TROUGH ACROSS THE AREA. BOTH NAM AND GFS BUFR
SOUNDINGS INDICATE A GOOD BIT OF DRY AIR IN THE MID LEVELS ALONG
WITH A WEAK CAP. HOWEVER... WITH SURFACE DEWPOINTS EXPECTED TO BE IN
THE UPPER 60S TO LOWER 70S (YIELDING MLCAPE IN THE 1500-2000 J/KG
RANGE FOR THE AFTERNOON) ALONG WITH THE SHARPENING SURFACE TROUGH
EXPECT WE WILL SEE SOME ISOLATED TO SCATTERED SHOWERS AND STORMS.
THUS... WILL CONTINUE A LOW END CHANCE FOR SHOWERS AND STORMS
THURSDAY AFTERNOON AND EVENING. WITH DEEP LAYER SHEAR AGAIN EXPECTED
TO REMAIN FAIRLY WEAK ON THE ORDER OF 15 TO 20 KTS DO NOT EXPECT ANY
ORGANIZED SEVERE WEATHER OUTBREAK. HOWEVER... A FEW STORMS MAY
BECOME STRONG TO SEVERE WITH THE MAIN THREAT OF DAMAGING DOWNBURST
WINDS AND MARGINALLY SEVERE HAIL. WITH LOW LEVEL THICKNESS VALUES
EXPECTED TO CLIMB TO AROUND 1420 METERS AND PARTLY SUNNY SKIES...
EXPECT WE WILL SE AFTERNOON HIGH TEMPS TOP OUT AROUND 90/LOWER 90S.
EXPECT CHANCES FOR SHOWERS AND STORMS TO DECREASE WITH THE LOSS OF
DAYTIME HEATING. OVERNIGHT LOWS ARE EXPECTED TO GENERALLY BE IN THE
LOWER 70S AGAIN... WITH PERHAPS A FEW OF THE URBAN AREAS REMAINING
IN THE MID 70S. -BSD
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON THE L/W PATTERN ACROSS
THE CONUS LATE WEEK INTO THE WEEKEND... WHICH IS EXPECTED TO
CONTINUE TO FEATURE TROUGHING IN THE EAST AND RIDGING WEST.
HOWEVER... THE EAST COAST TROUGH IS EXPECTED TO DEEPEN LATE THIS
WEEK/EARLY NEXT WEEKEND AS THE AFOREMENTIONED STRONG S/W DIVES
SOUTH/SOUTHEASTWARD OUT OF CANADA LATE WEEK AND DEVELOP A CLOSED LOW
ACROSS THE GREAT LAKES/OHIO VALLEY REGION... RESULTING IN A DEEP
TROUGH ACROSS THE EASTERN U.S. FOR THIS TIME OF YEAR (YESTERDAY HPC
NOTED THAT HEIGHTS MAY AVERAGE 1.5 TO 2.0 STANDARD DEVIATIONS BELOW
CLIMATOLOGY ACROSS PORTIONS OF THE EASTERN U.S. DURING THIS
TIMEFRAME). AS THIS HAPPENS AN ASSOCIATED SURFACE FRONT IS EXPECTED
TO APPROACH THE AREA LATE THIS WEEK... WITH THE ACTUAL FRONT
FORECAST TO MOVE INTO THE AREA IN THE FRIDAY NIGHT TO SATURDAY
TIMEFRAME... BEFORE STALLING OUT AND EVENTUALLY DISSIPATING ACROSS
EASTERN PORTIONS OF THE AREA. GIVEN THE STRENGTH OF THE TROUGH ALOFT
THIS LOOKS REASONABLE. THIS SETUP FOR THIS TIME OF YEAR WOULD FAVOR
AN INCREASE CHANCE OF SOME ORGANIZED SEVERE STORMS ALONG WITH A GOOD
CHANCE FOR WIDESPREAD SHOWERS AND STORMS... GIVEN THE IMPROVING
LARGE SCALE LIFT. WITH REGARD TO THE SEVERE THREAT THE GFS HAS 1200
TO 2000 J/KG OF MLCAPE FOR FRIDAY AFTERNOON... WITH DEEP LAYER SHEAR
INCREASING INTO THE 25 TO 30 KT RANGE. GIVEN THE IMPROVING DEEP
LAYER SHEAR VALUES AND USUAL SUMMERTIME INSTABILITY SPC HAS PLACED
US IN THE DAY 4-8 OUTLOOK FOR INCREASED SEVERE POTENTIAL... WITH THE
MAIN SEVERE THREAT FROM DAMAGING WINDS AND LARGE HAIL. GIVEN PW`S OF
AROUND 2 INCHES AGAIN EXPECTED WITH THIS SYSTEM... FLASH FLOODING
MAY BE A THREAT IF A GIVEN LOCATIONS RECEIVES SEVERAL SHOWERS AND
STORMS... ESPECIALLY IN URBAN AREAS.
CHANCES FOR SHOWERS AND STORMS WILL LINGER INTO SATURDAY AND
SUNDAY... ESPECIALLY ACROSS EASTERN PORTIONS OF THE AREA AS THE
FRONT BEGINS TO STALL AND EVENTUALLY DISSIPATES BY THE END OF THE
WEEKEND. CHANCES FOR SHOWERS AND STORMS APPEAR TO INCREASE AGAIN BY
EARLY NEXT WEEK AS ANOTHER (MUCH WEAKER) UPPER LEVEL DISTURBANCE MAY
APPROACH THE REGION.
HIGH TEMPS DURING THE PERIOD ARE EXPECTED TO GENERALLY BE IN THE MID
TO UPPER 80S... WITH LOWS RANGING FROM THE MID 60S TO LOWER 70S
(WITH SOME LOCATIONS ACROSS THE NORTHWEST POSSIBLY DROPPING INTO THE
LOWER 60S ON SUNDAY MORNING).
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 150 PM TUESDAY...
CEILINGS VARY ACROSS CENTRAL NC FROM MVFR TO VFR...BUT EVEN LOCALES
WITH VFR CONDITIONS STILL HAVE SCT STRATUS IN THE 1-3K FT RANGE.
EXPECT THESE CONDITIONS TO HOLD OR DETERIORATE THIS AFTERNOON AS
SHOWERS ISOLATED THUNDERSTORMS DEVELOP AND MOVE INTO THE AREA FROM
THE SOUTH. HEAVY RAIN AND PERIODS OF IFR/LIFR VSBYS WILL BE
POSSIBLE WITH THE HEAVIER SHOWERS...WHICH ARE MORE LIKELY AT
KRDU...KRWI...AND KFAY THROUGH MIDNIGHT. AFTER MIDNIGHT...MOST OF
THE SHOWERS AND STORMS WILL DIMINISH AND/OR MOVE EAST OF THE
AREA. HOWEVER...CEILINGS ARE LIKELY TO LOWER TO AT LEAST IFR
LEVELS AGAIN BY 09Z...WITH THE POSSIBILITY OF FOG GIVEN THE
WIDESPREAD RAIN IN THE PAST 24 HOURS.
IMPROVING CONDITIONS ARE EXPECTED FOR MUCH OF CENTRAL NC ON
WEDNESDAY. SCATTERED SHOWERS AND STORMS WILL BE POSSIBLE DURING THE
AFTERNOON HOURS...BUT CEILINGS SHOULD LIFT AND SCATTER BY LATE
MORNING AND HIGH END MVFR TO VFR CONDITIONS SHOULD PREVAIL FOR MANY
LOCATIONS.
AFTERNOON SHOWERS/STORMS AND MORNING STRATUS/FOG ARE AGAIN THURSDAY.
A STRONGER STORM SYSTEM WILL APPROACH THE AREA FRIDAY...LEADING TO
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS FRIDAY AFTERNOON INTO
EARLY SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS/BSD
LONG TERM...BSD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EDT TUE AUG 7 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL DRIFT EAST ACROSS THE CAROLINAS AND
SOUTHERN VIRGINIA TODAY AND TONIGHT...AND LIE ALONG THE COASTAL
PLAIN ON WEDNESDAY. ANOTHER UPPER LEVEL TROUGH WILL AFFECT OUR
REGION FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...
AREAS OF LIGHT TO MODERATE RAIN STRETCH FROM THE SOUTHERN PIEDMONT
TO THE NORTHERN COASTAL PLAIN THIS MORNING...ALONG A SHEARED OUT
VORTICITY AXIS NOTED IN WATER VAPOR AND RAP 500MB ANALYSIS. WHILE
ALL OF THE CWA OVERCAST...THE LOW STRATUS IS THICKEST OVER THE FROM
THE TRIANGLE WESTWARD TO THE TRIAD....AND VISIBLE SATELLITE IMAGERY
SHOWS A VEIL OF MID CLOUDS STREAMING ACROSS THE WESTERN HALF OF THE
STATE. THUS...EVEN AS THE STRATUS SLOWLY LIFTS THIS MORNING...SOME
AREAS MAY STRUGGLE TO GET OUT OF THE 70S...ESPECIALLY IN THOSE AREAS
WHERE RAIN FALLS THROUGH MIDDAY. SOME BREAKS IN CLOUD COVER ARE
BEGINNING TO SHOW OVER THE SOUTHERN COASTAL PLAIN...AND TEMPS COULD
REACH THE MID 80S FROM FAYETTEVILLE TO THE SOUTHEAST. WHILE
CONFIDENCE IN THE TEMP FORECAST IS LOW... HAVE ATTEMPTED TO ADJUST
TEMPS DOWNWARD OVER THE WESTERN PIEDMONT USING MET MOS AND NAM/GFS
RAW 2M TEMP FIELDS BASED...WHICH YIELDS VALUES ROUGHLY IN THE 79-85
RANGE.
REGARDING POPS...A WEAK UPPER LEVEL LOW AND ASSOCIATED VORT MAX OVER
AL/GA THIS MORNING WILL BE DRAWN NORTHWARD TODAY AHEAD OF AN UPPER
LEVEL TROUGH APPROACHING FROM THE MIDWEST. MEANWHILE.. A WEAK UPPER
JET OVER THE MID ATLANTIC STATES IS FORECAST TO BUILD BACK TO THE
SOUTHWEST ACROSS VA...WHICH SHOULD PROVIDE SOME RIGHT ENTRANCE
REGION LIFT AND ALSO HELP PRECIP EXPAND BACK TO THE NORTH OF THE
CURRENT PRECIP AXIS. MOST CAMS SUGGEST PRECIP WILL SHIFT NORTH
TOWARD ACROSS THE PIEDMONT THIS MORNING...THEN SHIFT EASTWARD TOWARD
THE COASTAL PLAIN LATER THIS AFTERNOON AND EVENING WITH THE SHEAR
AXIS. MOST OF THE WESTERN PIEDMONT SHOULD REMAIN RELATIVELY STABLE
AS COMPARED TO THE EASTERN PIEDMONT AND COASTAL PLAIN...WHERE
MODIFICATION OF THE 12Z KMHX RAOB SUGGEST 1000-1500 J/KG OF MLCAPE
IS POSSIBLE IF TEMPS CAN REACH THE MID 80S. DEEP LAYER SHEAR
FORECASTS CONTINUE TO BE BELOW 20KT...SO SEVERE POTENTIAL REMAINS
LOW AND WILL BE CONFINED TO STRONGER PULSE STORMS. HAVE MADE SOME
ADJUSTMENTS TO THE TIMING OF POPS THIS MORNING...BUT OVERALL THE
SHOWERS WILL BE NUMEROUS THIS AFTERNOON WITH SCATTERED STORMS AND
HEAVY RAIN MAINLY EAST.
FLASH FLOOD GUIDANCE HAS RECOVERED TO NORMAL VALUES FOR MOST AREAS
THIS MORNING. THE EXCEPTIONS APPEARS TO BE MAINLY RANDOLPH AND
STANLEY COUNTIES WHERE THE HEAVIEST RAIN FELL MONDAY. ONE TO TWO
INCHES IN AN HOUR OR TWO COULD CAUSE SOME FLOODING ISSUES IN THOSE
AREAS IF HEAVIER SHOWERS MATERIALIZE LATER TODAY. -SMITH
TONIGHT...BEST FOCUS FOR SHOWERS WILL BE ACROSS THE COASTAL PLAIN
THE FIRST HALF OF THE EVENING AS SHEAR AXIS DRIFTS EAST THOUGH
SHOULD SEE COVERAGE DECREASE BY MIDNIGHT AS AIR MASS STABILIZES AND
BEST LOW LEVEL MOISTURE TRANSPORT SHIFTS MORE TO THE IMMEDIATE COAST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT...WITH THE SHEAR AXIS CLOSER TO THE
COAST...EXPECT A RETURN TO MORE TYPICAL SUMMERTIME PATTERN OVER THE
PIEDMONT WITH RANDOM...DIURNALLY DRIVEN CONVECTION EXPECTED. SURFACE
PROJECTIONS SUGGEST A DEWPOINT GRADIENT BETWEEN THE TRIAD AND THE
TRIANGLE/FAY AREAS...SO EXPECT CONVECTION TO INITIATE ALONG THIS
FEATURE BY EARLY-MID AFTERNOON WITH CONVECTION DRIFTING EAST-SE.
THIS SUGGEST MORE COVERAGE IN THE SE VERSUS NW. PLAN TO HAVE POPS 30
PERCENT NW TO 50 PERCENT SE. PERIODS OF SUN PRIOR TO CONVECTION
INITIATION SHOULD LEAD TO AFTERNOON CLOSE TO NORMAL (UPPER 80S TO
AROUND 90). ANY CONVECTION WED EVENING SHOULD DIMINISH WITH LOSS OF
HEATING. PARTIAL CLEARING MAY ALLOW FOR THE DEVELOPMENT OF AREAS OF
FOG BY DAYBREAK THU. MIN TEMPS UPPER 60S TO LOWER 70S.-WSS
THURSDAY AND THURSDAY NIGHT:
BRIEF WESTERLY MID LEVEL FLOW IS EXPECTED TO AGAIN BACK TO
SOUTHWESTERLY ACROSS OUR AREA ON THURSDAY AS THE EAST COAST TROUGH
BEGINS TO DEEPEN AGAIN AS A STRONG S/W ALOFT DROPS
SOUTH/SOUTHEASTWARD OUT OF CANADA INTO THE UPPER MIDWEST AND GREAT
LAKES REGION. AT THE SURFACE MODELS INDICATE A SHARPENING
PIEDMONT/LEE SIDE TROUGH ACROSS THE AREA. BOTH NAM AND GFS BUFR
SOUNDINGS INDICATE A GOOD BIT OF DRY AIR IN THE MID LEVELS ALONG
WITH A WEAK CAP. HOWEVER... WITH SURFACE DEWPOINTS EXPECTED TO BE IN
THE UPPER 60S TO LOWER 70S (YIELDING MLCAPE IN THE 1500-2000 J/KG
RANGE FOR THE AFTERNOON) ALONG WITH THE SHARPENING SURFACE TROUGH
EXPECT WE WILL SEE SOME ISOLATED TO SCATTERED SHOWERS AND STORMS.
THUS... WILL CONTINUE A LOW END CHANCE FOR SHOWERS AND STORMS
THURSDAY AFTERNOON AND EVENING. WITH DEEP LAYER SHEAR AGAIN EXPECTED
TO REMAIN FAIRLY WEAK ON THE ORDER OF 15 TO 20 KTS DO NOT EXPECT ANY
ORGANIZED SEVERE WEATHER OUTBREAK. HOWEVER... A FEW STORMS MAY
BECOME STRONG TO SEVERE WITH THE MAIN THREAT OF DAMAGING DOWNBURST
WINDS AND MARGINALLY SEVERE HAIL. WITH LOW LEVEL THICKNESS VALUES
EXPECTED TO CLIMB TO AROUND 1420 METERS AND PARTLY SUNNY SKIES...
EXPECT WE WILL SE AFTERNOON HIGH TEMPS TOP OUT AROUND 90/LOWER 90S.
EXPECT CHANCES FOR SHOWERS AND STORMS TO DECREASE WITH THE LOSS OF
DAYTIME HEATING. OVERNIGHT LOWS ARE EXPECTED TO GENERALLY BE IN THE
LOWER 70S AGAIN... WITH PERHAPS A FEW OF THE URBAN AREAS REMAINING
IN THE MID 70S. -BSD
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON THE L/W PATTERN ACROSS
THE CONUS LATE WEEK INTO THE WEEKEND... WHICH IS EXPECTED TO
CONTINUE TO FEATURE TROUGHING IN THE EAST AND RIDGING WEST.
HOWEVER... THE EAST COAST TROUGH IS EXPECTED TO DEEPEN LATE THIS
WEEK/EARLY NEXT WEEKEND AS THE AFOREMENTIONED STRONG S/W DIVES
SOUTH/SOUTHEASTWARD OUT OF CANADA LATE WEEK AND DEVELOP A CLOSED LOW
ACROSS THE GREAT LAKES/OHIO VALLEY REGION... RESULTING IN A DEEP
TROUGH ACROSS THE EASTERN U.S. FOR THIS TIME OF YEAR (YESTERDAY HPC
NOTED THAT HEIGHTS MAY AVERAGE 1.5 TO 2.0 STANDARD DEVIATIONS BELOW
CLIMATOLOGY ACROSS PORTIONS OF THE EASTERN U.S. DURING THIS
TIMEFRAME). AS THIS HAPPENS AN ASSOCIATED SURFACE FRONT IS EXPECTED
TO APPROACH THE AREA LATE THIS WEEK... WITH THE ACTUAL FRONT
FORECAST TO MOVE INTO THE AREA IN THE FRIDAY NIGHT TO SATURDAY
TIMEFRAME... BEFORE STALLING OUT AND EVENTUALLY DISSIPATING ACROSS
EASTERN PORTIONS OF THE AREA. GIVEN THE STRENGTH OF THE TROUGH ALOFT
THIS LOOKS REASONABLE. THIS SETUP FOR THIS TIME OF YEAR WOULD FAVOR
AN INCREASE CHANCE OF SOME ORGANIZED SEVERE STORMS ALONG WITH A GOOD
CHANCE FOR WIDESPREAD SHOWERS AND STORMS... GIVEN THE IMPROVING
LARGE SCALE LIFT. WITH REGARD TO THE SEVERE THREAT THE GFS HAS 1200
TO 2000 J/KG OF MLCAPE FOR FRIDAY AFTERNOON... WITH DEEP LAYER SHEAR
INCREASING INTO THE 25 TO 30 KT RANGE. GIVEN THE IMPROVING DEEP
LAYER SHEAR VALUES AND USUAL SUMMERTIME INSTABILITY SPC HAS PLACED
US IN THE DAY 4-8 OUTLOOK FOR INCREASED SEVERE POTENTIAL... WITH THE
MAIN SEVERE THREAT FROM DAMAGING WINDS AND LARGE HAIL. GIVEN PW`S OF
AROUND 2 INCHES AGAIN EXPECTED WITH THIS SYSTEM... FLASH FLOODING
MAY BE A THREAT IF A GIVEN LOCATIONS RECEIVES SEVERAL SHOWERS AND
STORMS... ESPECIALLY IN URBAN AREAS.
CHANCES FOR SHOWERS AND STORMS WILL LINGER INTO SATURDAY AND
SUNDAY... ESPECIALLY ACROSS EASTERN PORTIONS OF THE AREA AS THE
FRONT BEGINS TO STALL AND EVENTUALLY DISSIPATES BY THE END OF THE
WEEKEND. CHANCES FOR SHOWERS AND STORMS APPEAR TO INCREASE AGAIN BY
EARLY NEXT WEEK AS ANOTHER (MUCH WEAKER) UPPER LEVEL DISTURBANCE MAY
APPROACH THE REGION.
HIGH TEMPS DURING THE PERIOD ARE EXPECTED TO GENERALLY BE IN THE MID
TO UPPER 80S... WITH LOWS RANGING FROM THE MID 60S TO LOWER 70S
(WITH SOME LOCATIONS ACROSS THE NORTHWEST POSSIBLY DROPPING INTO THE
LOWER 60S ON SUNDAY MORNING).
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 728 AM TUESDAY...
A MID LEVEL TROUGH INTERACTING WITH THE VERY MOIST AIR OVER CENTRAL
NC WILL CAUSE SCATTERED TO NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
ACROSS THE AREA THROUGH TONIGHT. THE GREATEST COVERAGE AND INTENSITY
WILL OCCUR DURING THE LATE MORNING THROUGH THE EARLY EVENING HOURS.
IN VICINITY OF THE HEAVIER SHOWERS AND T-STORMS...EXPECT MVFR
CONDITIONS WITH BRIEF PERIODS OF IFR CEILING/VISIBILITY.
BULK OF THE CONVECTION WILL DIMINISH OVER THE PIEDMONT INCLUDING
KRDU...KINT...AND KGSO BY MIDNIGHT...WHILE CONTINUE WELL INTO THE
NIGHT AT KRWI AND KFAY. EXPECT PATCHES OF IFR CEILING AND MVFR
VISIBILITY FOG TO DEVELOP OVER CENTRAL NC AFTER 06Z WED AND PERSIST
THROUGH 13Z WED.
ONCE MORNING STRATUS/FOG DIMINISH WEDNESDAY MORNING...EXPECT MAINLY
VFR CONDITIONS. CONVECTION COVERAGE EXPECTED TO BE LESS THAN TODAY
AND MAINLY DIURNALLY DRIVEN. SCATTERED CONVECTION LATE WEDNESDAY
AFTERNOON SHOULD DIMINISH WITHIN AN HOUR OR TWO AFTER SUNSET.
EXPECT A REPEAT PERFORMANCE THURSDAY WITH MORNING STRATUS AND FOG
GIVING WAY TO VFR CONDITIONS (ASIDE FROM LATE AFTERNOON CONVECTION).
ANOTHER MID-UPPER LEVEL TROUGH WITH AN ATTENDANT SURFACE BOUNDARY
WILL INCREASE THE THREAT FOR SCATTERED TO NUMEROUS SHOWERS AND
T-STORMS FRIDAY AFTERNOON INTO EARLY SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS/BSD
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
355 AM EDT TUE AUG 7 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN STALLED JUST NORTH OF THE AREA
TODAY THROUGH LATE WEEK BEFORE MOVING TO NEAR THE COAST OVER THE
WEEKEND. VERY MOIST AIR WILL THE THREAT OF RAIN HIGH THROUGH LATE
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 335 AM TUESDAY...PER RADAR TRENDS...PRECIPITATION IS RAPIDLY
FILLING IN TO THE SW/W OF THE MHX CWA AND BEGINNING TO MOVE INTO
OUR SOUTHERN COASTAL PLAINS COUNTIES. HAVE UPPED POPS TO LIKELY
OVER ROUGHLY THE WESTERN HALF OF THE CWA THROUGH 12Z AS LATEST RAP
AND HRRR INDICATE THESE SHOWERS WILL CONTINUE TO STREAM NORTHEAST
INTO EASTERN NORTH CAROLINA. FOR THE REMAINDER OF THE
DAY...ATMOSPHERE REMAINS VERY MOIST WITH PRECIPITABLE WATER VALUES
NEAR 2 INCHES. THIS MOIST BOUNDARY LAYER COUPLED WITH A STALLED
SURFACE BOUNDARY TO THE NORTH AND SOME STRONG H5 VORTICITY
EMBEDDED WITHIN A SOUTHWEST FLOW ALOFT WILL LEAD TO WAVES OF
SHOWERS CONTINUING OVER THE AREA THROUGH THE DAY AND HAVE HIGH CHC
TO LIKELY POPS EVERYWHERE. CLOUDS/PRECIPITATION WILL HOLD TEMPS
DOWN AS WELL WITH MOST MAX TEMPERATURES ONLY INTO THE MIDDLE 80S.
WITH DECENT INSTABILITY...WILL ALSO SEE SOME EMBEDDED
THUNDER...BUT UPPER LEVELS REMAIN WARM AND SHEAR MINIMAL...SO THE
SEVERE THREAT WILL BE LIMITED TODAY. THE PRIMARY THREAT WILL BE
HEAVY RAINFALL AND HAVE THIS WORDING IN THE ZONE FORECAST/GRIDS
TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
AS OF 340 AM TUESDAY...THE AXIS OF THE HEAVIEST RAIN WILL SHIFT
TO THE SOUTH AND EAST TONIGHT TOWARD THE COAST AS ANOTHER STRONG
SHORTWAVE MOVES ALONG THE COAST AND AXIS OF HIGHEST MIXING RATIO
AND SURFACE THETA-E SHIFTS TO THE SOUTH. WILL LIKELY SEE SOME
EMBEDDED THUNDER GIVEN MODERATE INSTABILITY. WILL HAVE LIKELY POPS
OVER THE SOUTHERN HALF OF THE CWA TONIGHT...TAPERING BACK TO HIGH
CHC NORTH. MIN TEMPS WILL BE MOSTLY IN THE LOWER 70S DUE TO THE
RAIN-COOLED AIR.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 330 AM TUE...RAINY PATTERN WILL CONTINUE THROUGH WED WITH
PERIODS OF HEAVY RAIN LOOKING LIKELY...FOLLOWED BY SCATTERED SHOWERS
AND TSTORMS LATE IN THE WEEK.
FRONTAL BOUNDARY WILL REMAIN IN PLACE ACROSS E NC ON WED...AND WITH
UPR STAGNANT TROUGH IN PLACE...DYNAMICS WILL BE IN PLACE FOR ANOTHER
ROUND OF HEAVY RAIN. IN ADDITION...THE AREA WILL BE UNDER RIGHT
ENTRANCE REGION OF DEPARTING JET STREAK...SO LIFT WILL BE ENHANCED
WITH AREA OF STRONG MID LEVEL FGEN IN PLACE. THIS WILL ENHANCE
RAINFALL TOTALS...AND COULD BE A SEVERE TSTORM OR TWO WITH DEEP
LAYER SHEAR IN EXCESS OF 25 KT...THOUGH INSTABILITY WILL BE LIMITED
WITH EXTENSIVE CLOUD COVER AND RAIN. RAIN CHANCES CONFINED TO OUTER
BANKS BY LATE AFTERNOON AS AREA OF LIFT MOVES EASTWARD.
FRONTAL BOUNDARY PROGGED TO BE NEAR OR JUST OFF THE COAST WED
NIGHT...WITH LIKELY POPS CONFINED TO THE IMMEDIATE COAST.
FOR THUR...IT APPEARS A DRIER DAY IS ON TAP WITH A BRIEF RESPITE
FROM THE WIDESPREAD RAIN...AS AREA WILL BE UNDER BROAD SW FLOW...
THOUGH MAJOR FORCING MECHANISM WELL TO THE WEST OF THE AREA.
MED/LONG RANGE MODELS IN GOOD AGREEMENT ON DEEP TROUGH CENTERED OVER
THE GREAT LAKES THUR NIGHT...TRANSLATING EASTWARD TOWARDS CENTRAL
APPALACHIANS FRI NIGHT. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD
SHOWERS THUNDERSTORMS INTO E NC FRI AND SAT. BEST CHANCES ATTM
APPEAR TO BE ON SAT...AS E NC WILL BE UNDER RIGHT ENTRANCE REGION OF
JET STREAK...TRANSLATING TO STRONG UPPER SUPPORT AND MID LEVEL FGEN
ONCE AGAIN. COULD BE A SEVERE TSTORM THREAT AS DEEP LAYER SHEAR WILL
BE PRESENT...AND PROVIDED INSTABILITY IS DECENT.
RAIN CHANCES MAY LINGER INTO LATE THIS WEEKEND THROUGH EARLY NEXT
WEEK...AS THERE ARE INDICATIONS FRONTAL BOUNDARY MAY GET HUNG UP
ACROSS E NC.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
/SHORT TERM TODAY AND TONIGHT/...
AS OF 345 AM WEDNESDAY...WIDESPREAD SHOWERS AND A FEW
THUNDERSTORMS WILL COVER THE AREA TODAY INTO TONIGHT. THERE WILL
BE LIKELY REDUCTIONS TO MVFR CEILINGS AND VSBYS IN THESE NUMEROUS
SHOWERS THROUGHOUT THE TAF PERIOD.
/LONG TERM WEDNESDAY THROUGH SATURDAY/...
AS OF 330 AM TUESDAY...WIDESPREAD RAIN AND THUNDERSTORMS WILL PLAGUE
E NC ON WED...WITH REDUCTIONS IN VSBY/CIG TO IFR POSSIBLE AT TIMES.
MUCH DRIER DAY ON THUR ON TAP...WITH CONDITIONS IMPROVING TO VFR ALL
AREAS. WILL SEE MORE SHOWER ACTIVITY FRI AND SAT...WITH MORE TEMPO
REDUCTIONS TO MVFR OR LOWER POSSIBLE.
&&
.MARINE...
/SHORT TERM TODAY AND TONIGHT/...
AS OF 345 AM TUESDAY...MARINE FORECAST REMAINS STEADY STATE WITH
SW WINDS OF 10 TO 15 KNOTS CONTINUING FOR TODAY AND TONIGHT WITH
SEAS IN THE 2 TO 3 FOOT RANGE. LATEST BUOY OBSERVATIONS SHOWING A
BIT MORE OF A SOUTHEAST SWELL COMPONENT AFFECTING THE NORTHERN
WATERS AT 10 TO 13 SECONDS. WINDS MAY GUST TO 20 KNOTS IN
CONVECTION WITH NUMEROUS SHOWERS AND A FEW TSTMS TODAY...BUT THE
GUSTINESS WILL BE SHORT-LIVED. NO SIGNIFICANT CHANGES TO THE
SHORT TERM FORECAST ARE NEEDED.
/LONG TERM WEDNESDAY THROUGH SATURDAY/...
AS OF 330 AM TUESDAY...SW FLOW WILL PERSIST THROUGH THE LONG TERM...
WITH WINDS 15 TO OCNL 20 KT WED THROUGH FRI. SEAS WILL GRADUALLY
BUILD TOWARDS 6 FEET...REACHING 6 FEET SOMETIME LATE FRIDAY...AS
WINDS REACH 20 TO 25 KT FRI NIGHT THROUGH SAT AS GRADIENT IS PINCHED
WITH AN APPROACHING DEEP TROUGH OF LOW PRES. WINDS AND SEAS DIMINISH
TO BELOW SCA LATE IN THE WEEKEND.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...TL
AVIATION...CTC/TL
MARINE...CTC/TL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1245 AM EDT TUE AUG 7 2012
.SYNOPSIS...
A STATIONARY FRONT EXTENDING FROM THE MID-ATLANTIC TO THE LOWER
MISSISSIPPI VALLEY WILL REMAIN FOR THE NEXT SEVERAL
DAYS...EVENTUALLY DISSIPATING LATE THIS WEEK. A COLD FRONT WILL
APPROACH FROM THE NORTHWEST FRIDAY AND MOVE THROUGH THE STATE THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1245 AM TUESDAY...BAND OF LIGHT TO MODERATE SHOWERS IS
GRADUALLY DIMINISHING IN COVERAGE ACROSS THE NORTH/NORTHEASTERN
COUNTIES EARLY THIS MORNING. HOWEVER...WITH ADDITIONAL SHORTWAVE
ENERGY APPROACHING FROM THE WEST LATER IN THE NIGHT...THINK SOME
REDEVELOPMENT IS POSSIBLE ACROSS THE NORTHERN COASTAL PLAINS AND
SOUND COUNTIES. AS A RESULT...WILL HAVE HIGH CHC POPS FOR THE NORTHERN
TIER THROUGH THE OVERNIGHT HOURS. ALSO SEEING SHOWERS INCREASING
IN COVERAGE SOUTH OF WILMINGTON AND WILL CARRY CHANCE POPS OVER
THE SOUTHERN COASTAL SECTIONS TOWARD MORNING AS LATEST RAP BRINGS
THIS ACTIVITY INTO THE SOUTHERN CWA. OTHER AREAS WILL BE IN A
SLIGHT CHC POP RANGE THROUGH EARLY MORNING. MIN TEMPERATURES WILL
RANGE IN THE LOWER 70S IN RAIN COOLED AREAS AND 75 TO 80 DEGREES
ELSEWHERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
AS OF 225 PM MON...WEAK SURFACE LOW OVER THE LOWER GULF STATES
WILL MOVE NORTHEAST ALONG A TROF OF LOW PRESSURE EXTENDING THROUGH
CENTRAL GEORGIA TO CENTRAL NORTH CAROLINA. THIS WILL HELP DEEPEN
THE MOISTURE ACROSS THE AREA. PRECIP WATER VALUES REACH JUST OVER
2.3 INCHES BY TUESDAY AFTERNOON. LIFT WILL INCREASE DURING THE DAY
AIDED BY AN ELONGATED VORT LOBE IN THE MID LEVELS APPROACHING FROM
THE WEST. LIKELY POPS ACROSS THE WEST AND NORTH WITH 40-50 PERCENT
ELSEWHERE. HIGHS GENERALLY IN THE MID 80S THROUGHOUT DUE TO
INCREASED CLOUD COVER AND CONVECTION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
AS OF 225 PM MONDAY...WILL REMAIN UNSETTLED FOR MUCH OF THIS
PERIOD. WEAK UPR TRF TO THE NW COMBINED WITH AXIS OF DEEP MOISTURE
OVER ERN NC WILL LEAD TO SCT TO NUMEROUS SHRA AND TSRA TUE NIGHT
INTO THU. WILL HAVE HIGH CHC TO LIKELY POPS MUCH OF THE PERIOD.
SHEAR ALOFT REMAINS WEAK AND THIS SHLD LIMIT THE SEVERE THREAT.
MUCH STRONGER UPR TRF WILL APPROACH FRI INTO SAT WITH BETTER SHEAR
AND GREATER THREAT OF SEVERE. FOR NOW WILL CONT CHC POP FOR LATE
IN THE WEEK....LATER SHIFTS MAY BE ABLE TO ADJUST UP AS TIMING OF
FEATURES BECOMES CLEARER. MAY GET A BRIEF LULL IN PRECIP SUNDAY AS
ECMWF SHOWS SOME DRIER AIR SPREADING IN AS WEAKENING FRONT MAKES
IT TO CST. UPR TRF NEVER PUSHES THRU AND LOOKS LIKE MOISTURE AND
SCT SHRA/TSRA WILL RETURN EARLY NEXT WEEK. CLOUDS AND PRECIP SHLD
KEEP HIGH TEMPS IN THE 80S WITH LOWS MAINLY IN THE 70S THRU THE
PD. EXPECT MANY AREAS WILL RECEIVE 2+ INCHES OF RAINFALL THRU THE
LONG TERM FCST.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /TONIGHT AND TUE/
AS OF 1030 PM MON...HIGH PRES OFF THE SE COAST CONTINUES TO BRING
MOIST S/SWLY FLOW ACROSS RTES THROUGH THE TAF PERIOD WHILE A
FRONTAL BOUNDARY REMAINS STALLED ACROSS THE MID ATLANTIC TO THE
DEEP SOUTH. HEAVIEST CONVECTION HAS WANED LATE THIS EVENING WITH
HEAVIEST SHOWERS AND TSTMS ACROSS NERN RTES WITH LIMITED IMPACT AT
THE TERMINALS...ALTHOUGH COULD SEE AN ISOLATED SHOWER AT PGV OVER
THE COUPLE HOURS. AN UPPER LEVEL WAVE IS PROGGED BY SEVERAL
MODELS TO IMPACT THE REGION LATE TONIGHT WHICH COULD SERVE TO
INITIATE ADDITIONAL CONVECTION DURING THE PRE-DAWN HOURS. A MOIST
AND UNSTABLE AIRMASS PERSISTS TUE AND EXPECT SCATTERED TO NUMEROUS
SHOWERS ACROSS ERN NC. OUTSIDE OF CONVECTION FLIGHT CONDITIONS
EXPECTED TO PRIMARILY BE VFR BUT COULD SEE PATCHY FOG DEVELOP LATE
TONIGHT BRIEFLY LOWERING CIGS.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 225 PM MONDAY...SCT TO NUMEROUS SHRA AND TSRA WILL CONT THRU
THE PERIOD WITH BRIEF REDUCTIONS IN CIGS/VSBYS AS CONVECTION
CROSSES TAF SITES. SATURATED LOW LVLS WILL LIKELY LEAD TO SOME
LATE NIGHT AND MORN STRATUS AND FOG WITH PDS OF MVFR/IFR.
&&
.MARINE...
SHORT TERM /TONIGHT AND TUE/
AS OF 1245 AM TUESDAY...HAVE TONED DOWN WINDS A BIT AS CONVECTION
HAS WEAKENED OVER THE NORTHERN WATERS. MOST AREAS WILL HAVE SW
WINDS OF 10 TO 15 KNOTS OVERNIGHT WITH SEAS RIGHT AROUND 3 FEET. A
RATHER STAGNANT PATTERN WILL CONTINUE IN THE SHORT TERM WITH A
STATIONARY FRONT EXTENDING FROM THE MID-ATLANTIC TO THE LOWER
MISSISSIPPI VALLEY...AND THE BERMUDA HIGH OFFSHORE.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 225 PM MONDAY...FAIRLY QUITE TUE NIGHT INTO THU MORN WITH
S/SW WINDS 15 KTS OR LESS AND SEAS 2 TO 4 FT. SW WINDS WILL BE
INCREASING LATER THU AND ESPCLY FRI AS COLD FRONT
APPROACHES...LOOKS LIKE WINDS OF 15 TO 25 KTS FRI WITH SEAS
REACHING 6 FT OR MORE OVER MUCH OF THE OUTER WTRS FRI INTO EARLY
SAT. GRDNT WILL LOOSEN SAT AS FRONT GETS CLOSER AND BEGINS TO
WEAKEN...THIS WILL LEAD TO DIMINISHING SW WINDS AND SEAS SUBSIDING
TO 3 TO 5 FT SAT AFTN.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HSA
NEAR TERM...CTC
SHORT TERM...HSA
LONG TERM...RF/HSA
AVIATION...RF/SK
MARINE...CTC/RF/SK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
856 PM CDT WED AUG 8 2012
.DISCUSSION...
A WEAK SFC BOUNDARY MOVING INTO THE NORTHERN CWA HAS RESULTED IN
A BIT MORE CONVECTIVE ACTIVITY THEN EXPECTED...WITH A FEW ISOLATED
SHOWERS EVEN DEVELOPING AS FAR WEST AS THE DEVILS LAKE BASIN.
BUMPED UP POPS FOR THE NORTHERN CWA THIS EVENING...BUT THINK THAT
ACTIVITY WILL BECOME MORE ISOLATED AFTER WE LOSE DAYTIME HEATING.
KEPT THE POPS SLIGHT FOR THE AFTER MIDNIGHT PERIOD. WILL HAVE TO
WATCH THE NORTHWESTERN CWA AS THE HRRR IS INDICATING THE
POSSIBILITY OF FOG FORMATION. THERE WILL BE PLENTY OF LOW LEVEL
MOISTURE...BUT AT THIS POINT THINK THAT NORTHERLY WINDS BEHIND THE
BOUNDARY WILL KEEP US FAIRLY MIXED SO WILL KEEP FOG MENTION OUT
FOR NOW. TEMPERATURES CONTINUE TO SEEM ON TRACK TO BOTTOM OUT IN
THE 50S.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE WITH SOME SHOWERS MOVING INTO THE
KTVF VICINITY THIS EVENING. WILL WATCH KDVL AND POSSIBLY KGFK FOR
SOME PATCHY FOG FORMATION TOWARDS MORNING...BUT THINK THAT
NORTHERLY WINDS PICKING UP TO AROUND 8 KTS WILL KEEP US MIXED SO
WILL LEAVE OUT OF TAFS FOR NOW. VFR CONDITIONS AND NORTH TO
NORTHEASTERLY WINDS AT AROUND 10 KTS WILL CONTINUE FOR MOST OF THE
DAY TOMORROW.
&&
.PREV DISCUSSION... /ISSUED 247 PM CDT WED AUG 8 2012/
SHORT TERM...
MAIN FORECAST CHALLENGE WILL BE PCPN CHANCES WITH THE SHORT WAVE
TONIGHT AND THEN AGAIN BY SAT. WILL UTILIZE A MODEL BLEND FOR THE
SHORT TERM FORECAST.
TONIGHT...PCPN DRIED UP PRETTY QUICKLY THIS AFTERNOON WITH THE
THICKEST CLOUD COVER STILL LINGERING IN THE FAR SOUTH. THERE WAS A
FAIR AMOUNT OF FOG IN THE CLEARING ZONE EARLY THIS MORNING AND
THIS SEEMS TO HAVE RESULTED IN A FAIRLY EXTENSIVE CUMULUS FIELD
THIS AFTERNOON. MOST OF THIS CUMULUS SHOULD THIN OUT WITH LOSS OF
HEATING BUT THERE IS ANOTHER SHORT WAVE DROPPING SOUTHWARD OUT OF
MANITOBA. THIS WAVE IS CURRENTLY NEAR THE MANITOBA LAKES REGION
AND SHOULD SWING INTO NORTHWEST MN TONIGHT. INHERITED FORECAST HAD
SOME CHANCES FOR PCPN TONIGHT TO ACCOUNT FOR THIS AND WILL KEEP
THEM...WHICH MAINLY AFFECTS THE NORTHEAST FA. WITH CLEARING SKIES
AND LIGHT WINDS THERE COULD BE SOME FOG AROUND BUT CONFIDENCE IS
NOT TOO HIGH. THEREFORE WILL LEAVE ANY MENTION OF FOG OUT OF THE
FORECAST FOR NOW AND LET LATER SHIFTS KEEP AN EYE ON IT.
THU-SAT...RIDGING BUILDS INTO THE REGION BEHIND THE DEPARTING
SHORT WAVE RESULTING IN A QUIET PERIOD FOR THU THRU FRI NIGHT.
SYSTEM THAT WAS ON TRACK FOR SAT LOOKS A BIT SLOWER AND POSSIBLY
WEAKER. GENERAL MODEL CONSENSUS NOW KEEPS THE MOST PCPN OVER
CENTRAL ND DOWN INTO NORTHEAST SD.
LONG TERM (SAT NIGHT-WED)...
MODELS IN FAIR AGREEMENT AND SHOULD SEE SEASONAL TEMPERATURES FOR
THE EXTENDED PERIOD. CHC OF PCPN CONFINED TO THE NORTH AND EAST
UNDER THE NW FLOW ALOFT AT THE BEGINNING OF NEXT WEEK. CHC OF PCPN
INCREASES ACROSS THE CFWA AS A STRONGER WAVE IS PROGGED TO MOVE
ACROSS THE NORTHERN PLAINS...SOUTHERN CANADA AND BRING INSTABILITY
AND FORCING TO THE REGION TUESDAY AND WEDNESDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
955 PM EDT WED AUG 8 2012
.SYNOPSIS...
MID LEVEL SHORT WAVE AXIS CROSSES NORTHERN WEST VIRGINIA BEFORE
MIDNIGHT. COLD FRONT AFFECTS THE AREA THURSDAY AND FRIDAY. HIGH
PRESSURE BUILDS IN THIS WEEKEND WITH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 02Z...HAVE SURFACE FRONT FROM NEAR PIT ON SW TO CMH...CVG...THEN
WEST ACROSS SOUTHERN INDIANA. 00Z RAP SHOWS MAIN 500 VORT MAX
CROSSING NRN WV MTNS BY 03Z...BUT HAS A WEAKENING VORT LINGERING IN
NORTH CENTRAL WV THROUGH 06Z. MAY BE HELPING A FEW LINGERING STORMS
CROSSING THE OHIO RIVER AT 02Z.
WILL INCREASE AREAL COVERAGE OF THE FOG WHERE IT RAINS IN NRN
CENTRAL WV...BUT NOT CONFIDENT ON THE EXACT INTENSITY. WILL LIMIT
THE FOG IN SOUTHEAST OHIO SINCE BOUNDARY LAYER WINDS STAY UP...AND
CLOUDS WITH THE NEXT 500 VORT MAX SHOULD BE APPROACHING BY THE
PREDAWN HOURS.
ALSO...INCREASED POPS A BIT FASTER FOR OUR SOUTHEAST OHIO COUNTIES
DURING THE PREDAWN...WITH MORE SUPPORT ARRIVING...BEFORE LIFTING NE.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
MODELS IN REASONABLE AGREEMENT WITH THE MASS FIELDS AS VIGOROUS
UPPER LEVEL TROUGH AND ATTENDING COLD FRONT AFFECT OUR AREA FOR THE
END OF THE WORKWEEK.
IT IS SOMEWHAT OF A COMPLEX SYSTEM...AS THERE IS A LEAD UPPER TROUGH
OUT AHEAD OF THE MAIN UPPER TROUGH. THIS LEAD UPPER TROUGH WILL
OUTRUN THE FRONT AND MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS
THURSDAY NIGHT. WITHOUT A LOW LEVEL FOCUSING MECHANISM...WILL STAY
IN CHANCE CATEGORY. TEMPS WILL BE ON THE WARM SIDE OF GUIDANCE WITH
MOISTURE AND CLOUDS IN INCREASING SOUTHERLY FLOW.
THE COLD FRONT WILL WAIT FOR THE MAIN UPPER TROUGH SWINGING AROUND A
DEVELOPING CLOSED CENTER OVER THE GREAT LAKES FRIDAY...WHICH WILL
THEN ACCELERATE THE FRONT EASTWARD DURING FRIDAY. AGAIN...AS WITH
THE LAST SYSTEM...LOTS OF CLOUDS LIMITING HEATING AND TIMING OF THE
FRONT WILL LESSEN DESTABILIZATION FOR FRIDAY CONVECTION.
HOWEVER...GOOD DYNAMICS WILL STILL SUPPORT A BAND OF ORGANIZED
CONVECTION ALONG AND AHEAD OF THE FRONT ON FRIDAY. FOR TIMING...WILL
STILL GO WITH THE SLIGHTLY SLOWER NAM SOLUTION. WILL UP POPS TO
LIKELY IN WEST AROUND 12Z...MOVE ACROSS THE REMAINDER OF THE AREA
DURING THE DAY FRIDAY. BY FRIDAY EVENING...WHILE THE FRONT ITSELF
MAY LAG A BIT BEHIND THE UPPER TROUGH...THE WESTERN EDGE OF THE
DEEPER MOISTURE WILL MOVE INTO THE MOUNTAINS. THUS...WILL LOWER THE
POPS SIGNIFICANTLY BEHIND THE WESTERN EDGE OPF THE DEEPER
MOISTURE..BUT STILL KEEP SOME POPS WITH THE FRONT ITSELF. FRONT DOES
EXITS THE MOUNTAINS BEFORE 12Z SATURDAY...WITH A DRY SLOT WORKING IN
OVER MUCH OF THE AREA BY SATURDAY MORNING. MOST POPS BASICALLY END
WITH THE PASSAGE OF THE FRONT LATER FRIDAY NIGHT. ALSO MUCH COOLER
TEMPS WORK IN BY SATURDAY MORNING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SATURDAY WILL BE A TRANSITION CAY AS THE PROGRESSIVE UPPER LOW OVER
THE GREAT LAKES LIFTS OUT. WRAPAROUND MOISTURE WILL BRING LOTS OD
CLOUDS FOR MUCH OF SATURDAY...WITH LINGERING SHOWERS MAINLY IN THE
NORTH. MUCH COOLER WITH TEMPS STRUGGLING TO REACH 80. HIGH PRESSURE
TAKES CONTROL SUNDAY AND EARLY NEXT WEEK WITH DRY CONDITIONS AND
SLOWING REBOUNDING TEMPS...THANKS TO SUNSHINE. ONE NOTE...THE GFS
LOOKS TO BE THE OUTLIER ON A CLIPPER SYSTEM AND PRECIP ON TUESDAY.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
CONTINUES TO BE A CHALLENGING AVIATION FORECAST OVERNIGHT IN REGARDS
TO DISSIPATING CONVECTION...LINGERING CLOUD DECK...AND FOG
FORMATION. MID LEVEL 500 MB VORT MAX AXIS PASSES EAST...OVER NRN WV
MOUNTAINS BY 03Z. CURRENTLY DO NOT HAVE HIGH ENOUGH POP FOR MENTION
CONVECTION AT ELKINS...SINCE TIMING IS AROUND 02Z/03Z...AND WAS
THINKING WEAKENING BY THEN. YET...CONVECTION SHOULD AFFECT PKB TO
CKB TO WESTON CORRIDOR 00Z TO 02Z. WITH LOCAL VSBY NEAR 3 MILES AND
CEILINGS 3 TO 4 THSD FT BKN.
INITIALLY WAS THINKING LESS FOG OVERNIGHT PKB TO CKB...BUT WITH THE
EVENING RAIN...WILL HOLD SOME THICKER FOG THERE 06Z TO 12Z.
YET...WITH BOUNDARY LAYER AND 925 MB FLOW...HAVE THE VISIBILITY MORE
VARIABLE ACROSS SOUTHEAST OHIO AND NORTHERN WEST VIRGINIA...COMPARED
TO THE EKN-CRW AND SOUTHERN WV COAL FIELDS FOR 06Z TO 12Z.
DID GO WITH LESS FOG TONIGHT AT HTS AND THE TRI STATE VICINITY THAN
WE PREVIOUS HAD...COUNTING ON NO SHOWERS AND THAT LOW LEVEL FLOW.
HAVE SOME 5 TO 8 THSD FT SCATTERED TO BROKEN CLOUDS FOR 12Z
THURSDAY...AND MAYBE A RAIN SHOWER IN SOUTHEAST OHIO. THEN CLOUDS
FORMING AT 3 TO 5 THSD FT SCATTERED TO BROKEN BY 15 TO 16Z.
BEST COVERAGE TO SCATTERED CONVECTION EXPECTED AFTER 18Z ACROSS
OHIO INTO NORTHERN WEST VIRGINIA COMPARED TO COUNTIES FURTHER TO THE
SOUTH.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LINGERING CLOUDS FROM EVENING CONVECTION COULD
DELAY OR DETER FOG FORMATION.
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 THU 08/09/12
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 M M H L L L L L L M
HTS CONSISTENCY H H M M H H H M H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H M L L L L L L L L L
PKB CONSISTENCY H M M M H L L L L L L M
CKB CONSISTENCY H H M M M L L L L L L M
AFTER 00Z FRIDAY...
IFR CONDITIONS POSSIBLE UNDER HEAVIEST SHOWERS/TSRA THURSDAY
AFTERNOON AND EVENING. IFR CONDITIONS ALSO POSSIBLE FRIDAY WITH
FRONT AS A RESULT OF CEILINGS AND SHOWERS/THUNDERSTORMS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...KTB
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
714 PM EDT WED AUG 8 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL REMAIN NEARLY STATIONARY ALONG THE OHIO
RIVER TONIGHT INTO THURSDAY. A STRONGER COLD FRONT AHEAD OF AN
ENERGETIC UPPER LEVEL LOW WILL BRING A ROUND OF SHOWERS AND
THUNDERSTORMS TO THE OHIO VALLEY ON THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
MADE MINOR ADJUSTMENTS TO THE FORECAST BASED ON CURRENT CONDITIONS
AND THUNDERSTORM ACTIVITY. A WEAK COLD FRONT HAD DROPPED SOUTH
INTO THE FORECAST AREA BY EARLY THIS EVENING. WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS CONTINUE ALONG AND AHEAD OF THE COLD
FRONT DUE TO WEAK LOW LEVEL FORCING AND AFTERNOON HEATING. THIS
FRONT WILL CONTINUE TO DROP SOUTH TONIGHT AND BECOME NEARLY
STATIONARY NEAR THE OHIO RIVER. THE SHOWER AND THUNDERSTORM
ACTIVITY WILL DECREASE THROUGH THE LATE EVENING HOURS. ANOTHER
CHANCE OF SHOWERS/THUNDERSTORMS WILL OCCUR IN THE EARLY MORNING
HOURS ASSOCIATED WITH AN UPPER LEVEL SYSTEM. THE RISK OF ISOLATED
SEVERE THUNDERSTORM ACTIVITY WILL DIMINISH THROUGH THE EVENING.
THE LOWS TONIGHT WILL BE WARMER THAN WEDNESDAY NIGHT WITH LOWS IN
THE MID 60S TO AROUND 70.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE WEAK COLD FRONT WILL LAY OUT AS A BOUNDARY ON THURSDAY AND
ANOTHER MID LEVEL SHORTWAVE WILL INTERACT WITH IT. THIS WILL BRING
A BETTER CHANCE OF THUNDERSTORMS ACROSS THE FORECAST AREA. WILL
ALSO SEE A CHANCE OF SEVERE WEATHER WITH THE MAIN THREAT BEING DAMAGING
WINDS. LOW PRESSURE WILL RIDE NE ALONG THE BOUNDARY THURSDAY NIGHT
IN RESPONSE TO AN UPPER LOW STRENGTHENING OVER THE WESTERN GREAT
LAKES AND CROSSING THE NORTHERN OHIO VALLEY BY EARLY FRI. MODELS
HANDLE THE TRACK OF THE LOW A LITTLE DIFFERENTLY WHICH WILL IMPACT
WHERE GREATEST PRECIPITATION OCCURRS. THE BEST COVERAGE OF
SHOWERS/THUNDERSTORMS WILL BE LATE THURSDAY INTO FRIDAY AS THE LOW
APPROACHES AND MOVES THROUGH THE OHIO VALLEY REGION.
WITH AN INCREASE IN CLOUDS AND PRECIPITATION THURSDAY...THE HIGH
TEMEPRATURES WILL BE COOLER THAN TODAY. MOST AREAS WILL SEE HIGHS
IN THE 80S EXCEPT AROUND 90 IN THE FAR SE. THE LOWS THURSDAY NIGHT
WILL BE IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
CLOSED UPPER LOW PROGGED TO BE OVER LOWER MICHIGAN AT 12Z FRIDAY
WITH SURFACE LOW POSITIONED OVER LAKE ERIE. THIS SYSTEM WILL
GRADUALLY PUSH FURTHER NORTHEASTWARD INTO CANADA THROUGH THE FIRST
PART OF THE WEEKEND...LEAVING MAINLY DRY AND COOLER CONDITIONS IN
ITS WAKE. WENT ON THE COOL SIDE OF GUIDANCE FOR FRIDAY AS
CLOUDS... PRECIPITATION...AND NORTHERLY FLOW BEHIND A FRONTAL
BOUNDARY WILL KEEP TEMPERATURES DOWN. FORECASTED HIGHS FOR FRIDAY
RIGHT NOW ARE ABOUT 10 DEGREES BELOW NORMAL. BOTH THE 00Z AND 12Z
ECMWF RUNS HAVE BEEN A LITTLE QUICKER TO PUSH THE SYSTEM OUT OF
THE AREA THAN THE LATEST NAM/GFS...SO DECIDED TO KEEP JUST SLIGHT
POPS INTO SATURDAY FOR THE FAR NORTHEASTERN CWA.
EXPECT A GRADUAL CLEARING SATURDAY AFTERNOON INTO THE OVERNIGHT AS
THE LOW PUSHES AWAY. LOWS SATURDAY NIGHT WILL BE COOL AS HIGH
PRESSURE BUILDS INTO THE REGION. WINDS WILL BECOME MORE SOUTHERLY BY
SUNDAY THE HIGH DRIFTS EAST OF THE REGION. THIS WILL BE THE START OF
A WARMING TREND THAT WILL CONTINUE THROUGH THE FIRST PART OF NEXT
WEEK WITH TEMPERATURES BACK IN THE 80S.
ONLY OTHER FEATURES OF CONCERN FOR THE EXTENDED PERIOD WILL ARRIVE
MONDAY INTO MONDAY NIGHT AS THE GFS BRINGS A DECENT SHORTWAVE AND
SURFACE LOW THROUGH THE REGION. NEITHER FEATURE HAS BEEN QUITE AS
DEVELOPED IN THE PAST TWO ECMWF RUNS AND THUS THE ECMWF HAS BEEN
TRENDING DRY. WENT AHEAD AND INTRODUCED SLIGHT POPS FOR THIS PERIOD
AS THE PAST FEW GFS RUNS HAVE BEEN CONSISTENT AND THE FEATURES ARE
AT LEAST EVIDENT IN THE ECMWF...BUT CONFIDENCE IN PRECIP IS NOT VERY
HIGH AT THIS TIME.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
CU FIELD IS TRYING TO FILL IN ACROSS THE AREA EARLY THIS AFTERNOON
AS WE CONTINUE TO WARM UP AND DESTABILIZE. ML CAPES ARE NOW INTO
THE 1500 TO 2000 J/KG RANGE ACROSS MUCH OF THE REGION. AS THE COLD
FRONT SAGS SLOWLY SOUTH ACROSS THE REGION THROUGH THIS EVENING...A
FEW THUNDERSTORMS MAY POP UP GIVEN THE INSTABILITY AND WEAK LOW
LEVEL FORCING. MEANWHILE...REMNANTS FROM EARLIER CONVECTION ARE
CONTINUING TO PROGRESS ACROSS ILLINOIS TOWARD WESTERN INDIANA. THE
LAST FEW RUNS OF THE RAP HAVE BEEN TRYING TO PIVOT A WEAKENING
LINE OF SHOWERS ASSOCIATED WITH THIS UP ACROSS AT LEAST OUR WESTERN
AREAS THROUGH EARLY EVENING. GIVEN THE UNCERTAINTY...THINK THE BEST
WAY TO COVER THE CHANCE RIGHT NOW IS JUST WITH A VCSH. ANOTHER
WEAK MID LEVEL SHORT WAVE WILL THEN PUSH TOWARD THE AREA LATE
TONIGHT INTO THURSDAY MORNING. EXPECT THE BEST CHANCE FOR ANY
PCPN ASSOCIATED WITH THIS TO BE ACROSS OUR NORTH AND WILL AGAIN
COVER WITH A VCSH. A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL
THEN DEVELOP OFF TO OUR WEST THROUGH THE AFTERNOON
HOURS...POSSIBLY AFFECTING CVG TOWARD THE END OF THEIR TAF
PERIOD.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...PARKER
NEAR TERM...PARKER
SHORT TERM...PARKER
LONG TERM...KURZ
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS TULSA OK
944 PM CDT WED AUG 8 2012
...UPDATE...
.DISCUSSION...
THE BULK OF EARLIER HEAVY CONVECTIVE ACTIVITY HAS MOVED SOUTH OUT
OF THE AREA. A COUPLE OF ISOLATED SMALL THUNDERSTORMS REMAIN IN
EASTERN OKLAHOMA... WITH SCATTERED STORMS CURRENTLY MOVING
SOUTHWARD TOWARD FAR NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS.
COOL AND MOIST OUTFLOW HAS MOVED ACROSS THE ENTIRE FORECAST AREA
WITH THE EXCEPTION OF FAR WESTERN OSAGE AND PAWNEE COUNTIES.
TEMPERATURES IN SOME RAIN-COOLED AREAS BRIEFLY DIPPED BELOW
FORECAST OVERNIGHT LOWS BEFORE WARMING AGAIN. HAVE NOT CHANGED
FORECAST LOWS SINCE DEWPOINTS HAVE NOW RISEN ENOUGH TO PUT A
BOTTOM UNDER TEMPS. HOWEVER... HAVE UPDATED DEWPOINTS IN THE GRIDS
AND ASSOCIATED CALCULATED GRID ELEMENTS. POPS FOR THE REMAINDER OF
THE NIGHT LOOK GOOD... WITH HIGHEST CHANCES REMAINING TOWARD THE
EAST. UPDATED PRODUCTS HAVE BEEN SENT.
&&
.PREV DISCUSSION... /ISSUED 625 PM CDT WED AUG 8 2012/
..UPDATE...
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SCATTERED STRONG TO SEVERE STORMS ALONG WITH MULTIPLE
OUTFLOW BOUNDARIES WILL CONTINUE TO RESULT IN ERRATIC
WIND DIRECTIONS AND SPEEDS FOR THE NEXT SEVERAL HOURS.
THUNDERSTORMS NEAR THE KMLC TAF SITE WILL GRADUALLY
DIMINISH AFTER 02Z...WITH ADDITIONAL STORMS POTENTIALLY
IMPACTING THE KFYV/KXNA SITES FROM THE NORTH BY 01-02Z.
EXPECT PERIODIC MVFR/IFR CONDITIONS IN AND NEAR STORMS.
MOST OF THE ACTIVITY SHOULD WEAKEN AFTER 06Z. A COLD
FRONT WILL MOVE THROUGH THE REGION THURSDAY MORNING
AND COULD RESULT IN A FEW LATE AFTERNOON STORMS FOR
KMLC/KFSM.
PREV DISCUSSION... /ISSUED 343 PM CDT WED AUG 8 2012/
DISCUSSION...
ONGOING CONVECTION WILL MAINTAIN A RISK OF DAMAGING DOWNBURST
WINDS ACROSS SE OK AND WESTERN AR INTO SUNSET...WITH ATTENTION
THEN TURNING TO EXPANDING CONVECTION ACROSS THE CENTRAL PLAINS.
THIS CONVECTION WILL BE FORCED BY A RESPECTABLE MID LEVEL WAVE FOR
EARLY AUGUST...AND LIKELY DEVELOP SOUTH AND EASTWARD AFTER SUNSET.
GIVEN THE DEEPLY MIXED AND NOT-YET OVERTURNED BOUNDARY LAYER IN
PLACE ACROSS NE OK...THE CONVECTION WILL HAVE A GOOD CHANCE OF
DEVELOPING INTO THE REGION. THE SOUTHWARD EXTENT SHOULD BE LIMITED
BY THE ONGOING CONVECTION AND ITS EFFECTS ON STABILIZING THE
BOUNDARY LAYER. THIS SCENARIO IS LARGELY SUPPORTED BY THE 18Z NAM
AND HRRR OUTPUT.
THE COLD FRONT ASSOCIATED WITH THE PASSING WAVE WILL MOVE INTO NE
OK BY SUNRISE THURSDAY...AND THROUGH MUCH OF THE FORECAST AREA BY
SUNSET THURSDAY. STORM CHANCES WILL RESIDE ALONG AND SOUTH OF THE
BOUNDARY PRIMARILY DURING THE AFTERNOON HOURS ON THURSDAY.
NOTICEABLY DRIER AND COOLER AIR WILL FOLLOW THE FRONT AND BRING
TEMPS NEAR NORMAL FRIDAY AND SATURDAY. RAINFALL FOOTPRINTS...OR
LACK THEREOF...MAY LARGELY AFFECT THE DEGREE OF COOLING GIVEN THE
VERY WARM GROUND TEMPS AND LACK OF CLOUD COVER BEHIND THE FRONT.
UPPER RIDGING WILL ATTEMPT TO EXPAND BACK EASTWARD OVER THE
WEEKEND...THOUGH IT LOOKS TO BE SUPPRESSED FURTHER SOUTH AND NOT
HAVE AS STRONG AS INFLUENCE AS RECENTLY. SOUTHERN PERIPHERY OF A
PASSING WAVE MAY SUPPORT PRECIP LATE SUNDAY INTO
MONDAY...OTHERWISE NO SIGNIFICANT PRECIP CHANCES ARE NOTED UNTIL
POSSIBLY JUST BEYOND THIS FORECAST TIME FRAME.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...06
LONG TERM....99
AREA FORECAST DISCUSSION
NWS TULSA OK
625 PM CDT WED AUG 8 2012
...UPDATE...
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SCATTERED STRONG TO SEVERE STORMS ALONG WITH MULTIPLE
OUTFLOW BOUNDARIES WILL CONTINUE TO RESULT IN ERRATIC
WIND DIRECTIONS AND SPEEDS FOR THE NEXT SEVERAL HOURS.
THUNDERSTORMS NEAR THE KMLC TAF SITE WILL GRADUALLY
DIMINISH AFTER 02Z...WITH ADDITIONAL STORMS POTENTIALLY
IMPACTING THE KFYV/KXNA SITES FROM THE NORTH BY 01-02Z.
EXPECT PERIODIC MVFR/IFR CONDITIONS IN AND NEAR STORMS.
MOST OF THE ACTIVITY SHOULD WEAKEN AFTER 06Z. A COLD
FRONT WILL MOVE THROUGH THE REGION THURSDAY MORNING
AND COULD RESULT IN A FEW LATE AFTERNOON STORMS FOR
KMLC/KFSM.
&&
.PREV DISCUSSION... /ISSUED 343 PM CDT WED AUG 8 2012/
DISCUSSION...
ONGOING CONVECTION WILL MAINTAIN A RISK OF DAMAGING DOWNBURST
WINDS ACROSS SE OK AND WESTERN AR INTO SUNSET...WITH ATTENTION
THEN TURNING TO EXPANDING CONVECTION ACROSS THE CENTRAL PLAINS.
THIS CONVECTION WILL BE FORCED BY A RESPECTABLE MID LEVEL WAVE FOR
EARLY AUGUST...AND LIKELY DEVELOP SOUTH AND EASTWARD AFTER SUNSET.
GIVEN THE DEEPLY MIXED AND NOT-YET OVERTURNED BOUNDARY LAYER IN
PLACE ACROSS NE OK...THE CONVECTION WILL HAVE A GOOD CHANCE OF
DEVELOPING INTO THE REGION. THE SOUTHWARD EXTENT SHOULD BE LIMITED
BY THE ONGOING CONVECTION AND ITS EFFECTS ON STABILIZING THE
BOUNDARY LAYER. THIS SCENARIO IS LARGELY SUPPORTED BY THE 18Z NAM
AND HRRR OUTPUT.
THE COLD FRONT ASSOCIATED WITH THE PASSING WAVE WILL MOVE INTO NE
OK BY SUNRISE THURSDAY...AND THROUGH MUCH OF THE FORECAST AREA BY
SUNSET THURSDAY. STORM CHANCES WILL RESIDE ALONG AND SOUTH OF THE
BOUNDARY PRIMARILY DURING THE AFTERNOON HOURS ON THURSDAY.
NOTICEABLY DRIER AND COOLER AIR WILL FOLLOW THE FRONT AND BRING
TEMPS NEAR NORMAL FRIDAY AND SATURDAY. RAINFALL FOOTPRINTS...OR
LACK THEREOF...MAY LARGELY AFFECT THE DEGREE OF COOLING GIVEN THE
VERY WARM GROUND TEMPS AND LACK OF CLOUD COVER BEHIND THE FRONT.
UPPER RIDGING WILL ATTEMPT TO EXPAND BACK EASTWARD OVER THE
WEEKEND...THOUGH IT LOOKS TO BE SUPPRESSED FURTHER SOUTH AND NOT
HAVE AS STRONG AS INFLUENCE AS RECENTLY. SOUTHERN PERIPHERY OF A
PASSING WAVE MAY SUPPORT PRECIP LATE SUNDAY INTO
MONDAY...OTHERWISE NO SIGNIFICANT PRECIP CHANCES ARE NOTED UNTIL
POSSIBLY JUST BEYOND THIS FORECAST TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 105 75 100 69 / 20 30 0 10
FSM 103 78 104 70 / 70 30 20 10
MLC 102 74 103 69 / 60 30 20 10
BVO 104 69 99 64 / 20 30 0 10
FYV 92 67 97 64 / 30 40 10 10
BYV 98 70 95 66 / 30 50 10 10
MKO 104 73 102 69 / 50 40 0 10
MIO 100 71 97 68 / 20 40 0 10
F10 104 75 102 70 / 40 30 10 10
HHW 100 75 103 73 / 30 30 30 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...18
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1113 AM CDT TUE AUG 7 2012
.UPDATE...
EXPANDED THE HEAT ADVISORY FARTHER NORTH TO INCLUDE
THE OKLAHOMA CITY METRO...LAWTON...SHAWNEE...AND
STILLWATER AREAS. ALSO...MADE SMALL ADJUSTMENTS
TO OTHER ELEMENTS TODAY.
&&
.DISCUSSION...
VERY HOT AND MORE HUMID WEATHER WILL PREVAIL THIS
AFTERNOON WITH ISOLATED THUNDERSTORMS.
MADE THE CHANGES TO THE HEAT ADVISORY AS DEEPER MOISTURE
AND HUMIDITY WITH DEWPOINTS MAINLY IN THE LOWER TO MID 60S WILL
YIELD HIGHER HEAT INDEX VALUES THIS AFTERNOON ESPECIALLY SOUTHEAST
OF AN ALTUS TO PONCA CITY LINE. THE 12Z KOUN SOUNDING DEPICTED PW
OF 1.58 INCHES WHICH IS 124 OF NORMAL AND HIGHER THAN THE PAST
SEVERAL DAYS. HEAT INDICES IN THE 103 TO 109 RANGE ARE EXPECTED.
REGARDING RAIN CHANCES THIS AFTERNOON...ALTERED RAIN CHANCES TO
RESEMBLE THE LATEST HRRR RUNS. KEPT THE HIGHEST RAIN
CHANCES...AROUND 30 PERCENT...EAST OF I-35 WHERE APPEARS DEEPEST
MOISTURE AND WEAKEST CAPPING WILL OCCUR. NEARLY ANYWHERE CAN GET
WET...BUT DUE TO WEAK SHEAR...THINK MOST PLACES WILL REMAIN
RAINFREE.
ANY STORM THIS AFTERNOON MAY PRODUCE SEVERE DAMAGING WINDS OF 60
MPH OR GREATER DUE TO DCAPE VALUES 1200 TO 1800 J/KG. LOCALLY
HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING STRIKES ARE POSSIBLE
AS WELL WHICH MAY IGNITE FIRES.
AS FOR HIGHS THIS AFTERNOON...DID NOT ALTER THEM MUCH
DUE TO ONGOING CLOUD COVER AND CONVECTION. HOWEVER...THINK
THEY MAY BE TOO CONSERVATIVE. HIGHS MAY BE EVEN HOTTER THAN
CURRENTLY FORECAST...ESPECIALLY IF CLOUD COVER DECREASES.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 104 74 100 74 / 20 30 20 20
HOBART OK 105 73 99 74 / 30 30 20 20
WICHITA FALLS TX 105 76 101 76 / 20 20 20 20
GAGE OK 102 69 97 68 / 20 30 20 10
PONCA CITY OK 104 71 96 73 / 30 20 20 20
DURANT OK 103 75 98 76 / 30 20 30 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR OKZ012-013-
017>020-023>032-037>048-050>052.
TX...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR TXZ086-089-090.
&&
$$
17/03
AREA FORECAST DISCUSSION
NWS NORMAN OK
507 AM CDT TUE AUG 7 2012
.DISCUSSION...
SATELLITE HAS SHOWN ACCAS DEVELOPING IN VARIOUS AREAS THIS
MORNING AND ASSOCIATED SHOWERS AND THUNDERSTORMS HAVE ALSO
DEVELOPED IN THE PAST FEW HOURS. HRRR IS ABOUT THE ONLY MODEL THAT
HAS SHOWED THIS DEVELOPMENT AND IT EXPECTS THIS CONVECTION TO
DISSIPATE LATE MORNING. WILL PROBABLY HAVE STORM REDEVELOPMENT
THIS AFTERNOON... BUT AGAIN DO NOT EXPECT THE STORMS TO BE VERY
WIDESPREAD. TODAY WILL BE ANOTHER HOT DAY BEFORE TEMPERATURES COME
COOL SLIGHTLY AS UPPER RIDGE SHIFTS TO THE WEST. HEAT INDICES WILL
BE MARGINAL FOR THE CURRENT HEAT ADVISORY... BUT WILL LET IT RIDE
FOR TODAY. WILL LIKELY SEE ISOLATED TO SCATTERED STORMS EACH
PERIOD THROUGH THURSDAY WHEN A FRONT MOVES THROUGH THE AREA.
FORECAST HIGHS THROUGH THE REMAINDER OF THE FORECAST PERIOD WILL
BE ABOVE AVERAGE... BUT NOT AS HIGH AS RECENT DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 104 74 100 74 / 20 30 20 20
HOBART OK 105 73 99 74 / 30 30 20 20
WICHITA FALLS TX 105 76 101 76 / 20 20 20 20
GAGE OK 102 69 97 68 / 30 30 20 10
PONCA CITY OK 104 71 96 73 / 20 20 20 20
DURANT OK 103 75 98 76 / 20 20 30 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR OKZ039>048-
050>052.
TX...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR TXZ086-089-090.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
601 PM CDT WED AUG 8 2012
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW...
&&
.AVIATION...
A BROKEN LINE OF SHOWERS AND THUNDERSTORMS WAS LOCATED ALONG A
LINE FROM NEAR OZONA...TO FORT MCKAVETT...TO BRADY. EXPECT THIS
ACTIVITY TO CONTINUE TO MOVE SOUTH THROUGH THE NEXT COUPLE OF HOURS. AN
ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE AT MAINLY
KBBD...KJCT AND KSOA...WITH MOST OF THE ACTIVITY WINDING DOWN BY
02Z. BRIEF HEAVY RAINFALL AND GUSTY WINDS TO NEAR 40 MPH WILL BE
POSSIBLE WITH THESE STORMS. TONIGHT THROUGH LATE THURSDAY
MORNING...EXPECT VFR CONDITIONS AND LIGHT AND VARIABLE WINDS.
&&
.PREV DISCUSSION... /ISSUED 359 PM CDT WED AUG 8 2012/
SHORT TERM...
SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE HEARTLAND
AND CONCHO VALLEY THIS AFTERNOON. THIS ACTIVITY IS DEVELOPING
IN ASSOCIATION WITH LIFT FROM A WEAK SHORT WAVE THAT IS
OVERSPREADING THE AREA FROM THE NORTH. LATEST HRRR SEEMS TO BE
DOING A DECENT JOB SO FAR AND INDICATES ADDITIONAL DEVELOPMENT
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA THROUGH EARLY EVENING.
WILL MAINTAIN 30 POPS SOUTH AND SLIGHT CHANCE POPS NORTH ACROSS
THE BIG COUNTRY THROUGH THE EVENING HOURS. MAY STILL SEE SOME
LINGERING ACTIVITY ALONG THE I-10 CORRIDOR THROUGH LATE EVENING
BUT MOST OF THE CONVECTION SHOULD DISSIPATE AFTER SUNEST. THE MAIN
THREAT FROM THUNDERSTORMS WILL BE LOCALLY HEAVY RAINFALL...GUSTY
WINDS AND DANGEROUS CLOUD TO GROUND LIGHTNING.
DRIER AIR WILL FILTER INTO THE AREA FROM THE NORTH LATER TONIGHT AND
THURSDAY. THIS WILL RESULT IN DRY AND HOT CONDITIONS ACROSS THE AREA
WITH AFTERNOON HIGHS AROUND THE CENTURY MARK. CANNOT RULE OUT AN
ISOLATED STORM OR TWO ACROSS SOUTHEAST SECTIONS THURSDAY AFTERNOON
SO KEPT ISOLATED MENTION OVER THIS AREA.
LONG TERM...
AS AN UPPER TROUGH AND LOW DROP SOUTHEAST ACROSS THE LOWER
GREAT LAKES REGION...TRAILING PORTION OF ASSOCIATED COLD
FRONT WILL MOVE SOUTH INTO THE BIG COUNTRY THURSDAY NIGHT...
AND ACROSS THE REST OF WEST CENTRAL TEXAS ON FRIDAY. THIS
PORTION OF THE FRONT WILL BE WEAK HOWEVER...WITH THE MAIN
ADVECTION OF COOLER AIR EXPECTED TO BE TO THE NORTHEAST OF
OUR AREA. WITH WEAK SURFACE CONVERGENCE AND A DRIER AIRMASS
PROGGED...RAIN CHANCES LOOK LOOK TOO SMALL INCLUDE IN OUR AREA
WITH THE ARRIVAL/PASSAGE OF THIS FRONT. TEMPERATURES WILL BE
SLIGHTLY COOLER ACROSS THE BIG COUNTRY...WHERE HIGHS FRIDAY
ARE EXPECTED TO BE IN THE MID/UPPER 90S.
THE UPPER HIGH WILL BE CENTERED OVER NEW MEXICO DURING THE
WEEKEND. GIVEN ITS PROXIMITY...HOT AND DRY CONDITIONS CAN BE
EXPECTED FOR WEST CENTRAL TEXAS. THE WARMEST READINGS ARE
EXPECTED SUNDAY...WHEN HIGHS SHOULD RANGE FROM 100-105 DEGREES
AREAWIDE. LITTLE CHANGE IS INDICATED WITH THIS PATTERN THROUGH AT
LEAST EARLY NEXT WEEK. THE 12Z GFS AND ECMWF SHOW A WEAKENING WITH
THIS HIGH BY NEXT TUESDAY OR WEDNESDAY...WITH THE GFS BRINGING A
DISTURBANCE NORTH-NORTHEAST FROM THE LOWER RIO GRANDE VALLEY INTO
CENTRAL AND EASTERN TEXAS. GIVEN THAT THIS IS LATE DAY 6 AND DAY
7...LEANING AT THIS TIME TOWARD PERSISTENCE WITH THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 74 101 72 97 70 / 20 10 10 5 5
SAN ANGELO 74 101 73 101 70 / 30 20 10 10 5
JUNCTION 73 97 72 101 70 / 30 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DANIELS
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1125 PM CDT MON AUG 6 2012
.DISCUSSION...
SEE 06Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED AT THE TERMINALS THE NEXT 24 HOURS.
ISOLD TSTMS ARE POSSIBLE ACROSS ACROSS MUCH OF WEST CENTRAL TEXAS
AFTER 20Z TUE...HOWEVER WILL KEEP TSTMS OUT OF THE TERMINALS DUE
TO VERY SPARSE COVERAGE.
21
&&
.PREV DISCUSSION... /ISSUED 953 PM CDT MON AUG 6 2012/
UPDATE...
WEAKENING CONVECTION HAS MOVED INTO THE NORTHEAST PORTION OF THE
CWA NEAR THROCKMORTON AND WILL CONTINUE ITS DOWNWARD TREND AS IT
MOVES SSW. ADDITIONAL...MORE IMPRESSIVE...STORMS EXIST ALONG THE
I-35 CORRIDOR FORMING JUST NORTH OF THE RED RIVER NEAR THE
INTERSECTION OF THE LOW LEVEL JET AND A QUASI-STATIONARY SURFACE
FRONT. HOWEVER...THESE STORMS WILL MOVE GENERALLY SOUTH AND SHOULD
REMAIN TO THE EAST OF THE CWA. THE HRRR MAINTAINS THE CONVECTION
OVER THROCKMORTON COUNTY WELL INTO THE NORTHERN CONCHO VALLEY BUT
OTHER 3 KM WRF VARIETIES WEAKEN THIS CONVECTION OVER THE NEXT 1-2
HOURS. GIVEN THE PERSISTENCE OF LAST NIGHTS ACTIVITY...I HAVE
KEPT MENTION OF THUNDERSTORMS FOR THE BIG COUNTRY THROUGH 09Z WITH
DRY CONDITIONS THEREAFTER. I ALSO LOWERED MIN TEMPS JUST A BIT...
SHADING CLOSER TO WHAT WAS OBSERVED THIS MORNING WITH A SLIGHT
MODEL BLEND BUILT IN. GENERALLY LOW/MID 70S ARE EXPECTED ACROSS
THE CWA.
JOHNSON
PREV DISCUSSION... /ISSUED 350 PM CDT MON AUG 6 2012/
SHORT TERM...
LITTLE CHANGE TO FORECAST REASONING THE NEXT 24 HOURS. WEST
CENTRAL TEXAS WILL REMAIN ON THE EASTERN PERIPHERY OF THE UPPER
HIGH THAT WILL BE CENTERED OVER THE FOUR CORNERS REGION THE REST
OF THIS WEEK. WATER VAPOR IMAGERY ALREADY SHOWING BETTER MID
LEVEL MOISTURE ACROSS ACROSS THE AREA COMPARED TO THE PAST COUPLE
OF DAYS. THE INCREASE IN MOISTURE COUPLED WITH STRONG DAYTIME
HEATING WILL ALLOW FOR ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON AND EVENING AND AGAIN TUESDAY
AFTERNOON. THE BEST CHANCE FOR STORMS THROUGH THIS EVENING WILL
BE ACROSS THE BIG COUNTRY WHERE 20 POPS WERE ADDED.
OTHERWISE...WENT WITH ISOLATED WORDING ELSEWHERE THROUGH THE
EVENING HOURS.
SIMILAR SCENARIO FOR TUESDAY WITH BEST CHANCE FOR ISOLATED
CONVECTION ACROSS THE BIG COUNTRY TUESDAY AFTERNOON. TEMPERATURES
ON TUESDAY WILL BE SIMILAR TO TODAY WITH AFTERNOON HIGHS
GENERALLY A COUPLE OF DEGREES EITHER SIDE OF THE CENTURY MARK.
LONG TERM...
WEST CENTRAL TEXAS WILL BE THE EASTERN SIDE OF THE UPPER RIDGE
INTO NEXT WEEKEND...WITH NORTHERLY FLOW ALOFT. ISOLATED
THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE...WEDNESDAY INTO
THURSDAY...BUT BEST CHANCE OF A THUNDERSTORM WILL BE WEDNESDAY
NIGHT AS GFS MODEL BRINGS A WEAK COLD FRONT THROUGH THE REGION.
MAY STAY 2-3 DEGREES LESS HOT THURSDAY INTO SATURDAY...BUT UPPER
RIDGE/850 MB THERMAL TROUGH STRENGTHENS AGAIN SUNDAY INTO EARLY
NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 76 101 76 102 75 / 10 20 10 20 20
SAN ANGELO 74 102 75 102 73 / 5 10 10 20 20
JUNCTION 72 98 73 102 74 / 5 10 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
346 PM EDT TUE AUG 7 2012
.SYNOPSIS...
A PERIOD OF UNSETTLED WEATHER WILL CONTINUE THIS WEEK AS A FRONTAL
BOUNDARY OSCILLATES ACROSS THE MID ATLANTIC REGION. A STRONG COLD
FRONT WILL SWEEP ACROSS THE REGION ON FRIDAY...BRINGING A GENEROUS
COVERAGE OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER
AND DRIER WEATHER IS EXPECTED BY THE START OF THE NEXT WEEK AS
HIGH PRESSURE BUILDS INTO THE REGION.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 233 PM EDT TUESDAY...
A FRONTAL BOUNDARY WAS SLOWLY HEADING SOUTH THROUGH THE REGION. THE
FRONT...ALONG WITH DAYTIME HEATING...IS HELPING ISOLATED SHOWERS TO
DEVELOP THIS AFTERNOON NEAR THE CREST OF THE BLUE RIDGE FROM ROUGHLY
FLOYD VA...SOUTHWEST INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA.
OTHER ISOLATED SHOWERS WERE OVER PARTS OF THE MOUNTAIN EMPIRE REGION
OF SOUTHWEST VIRGINIA AND SOUTHSIDE VIRGINIA. THESE ARE EXPECTED TO
CONTINUE THROUGH THE AFTERNOON...AND PERHAPS INCREASE IN COVERAGE
AND GAIN A FEW STRIKES OF LIGHTNING. THIS FRONT WILL CONTINUE TO
SLOWLY HEAD SOUTH THROUGH THE NIGHT...SO THAT HIGH PRESSURE WILL BE
NOSING SOUTH INTO THE REGION BY WEDNESDAY.
THIS HIGH WILL BRING A TREND TOWARDS DECREASING CLOUDS OVERNIGHT
INTO EARLY WEDNESDAY MORNING. LIGHT WINDS...AND LINGERING BOUNDARY
LAYER MOISTURE BELOW THE NOCTURNAL INVERSION WILL HELP GENERATE
AREAS OF FOG TONIGHT ACROSS A GENEROUS PORTION OF THE AREA. WHILE
THERE IS BOUND TO BE SOME DENSE FOG...CONFIDENCE IN IT BEING
WIDESPREAD ARE NOT HIGH AT THIS TIME. WILL HIGHLIGHT THE POTENTIAL
FOR SOME DENSE FOG TONIGHT IN ALL BUT THE BLUEFIELD TO TAZEWELL
AREA. LOW TEMPERATURES TONIGHT WILL AVERAGE THREE TO FIVE DEGREES
COOLER THAN READINGS EXPERIENCED THIS MORNING.
ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR AS
PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH.
HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE
LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED SHOWERS
SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING FARTHER TO OUR
SOUTH...MORE SUNSHINE SHOULD YIELD HIGH TEMPERATURES ON WEDNESDAY
ABOUT THREE TO FIVE DEGREES WARMER THAN TODAY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 242 PM EDT TUESDAY...
CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE SHORT TERM
PERIOD AS AN UPPER LEVEL TROF AMPLIFIES OVER THE GREAT LAKES AND
INTO THE OHIO VALLEY BY FRIDAY.
IN ADVANCE OF THIS SYSTEM...TEMPERATURES SHOULD WARM TOWARD THE
WARMER NAM MOS VALUES ON THURSDAY AS THE LOW LEVEL THERMAL RIDGE
NOSES INTO OUR AREA. BEST CHANCES FOR THUNDERSTORMS ON THURSDAY WILL
BE IN THE WEST AS A LEAD SHORT WAVE (OVERDONE BY THE GFS) APPROACHES
OUR AREA AND INTERACTS WITH A MODERATELY UNSTABLE AIRMASS. KEPT POPS
IN THE EASTERN PORTION OF THE FORECAST AREA ON THURSDAY AS WEAK LOW
LEVEL CONVERGENCE ALONG A LEE-SIDE TROF SHOULD GENERATE SCATTERED
CONVECTION.
THIS CONVECTION MAY LINGER A FEW HOURS BEYOND SUNDOWN THURSDAY NIGHT
WITH SUPPORT FROM THE WEAK UPPER LEVEL WAVE MOVING THROUGH.
THE TREND OF THE MODELS FOR FRIDAY`S SYSTEM HAS BEEN TO SLOW ITS
EASTWARD PROGRESS SLIGHTLY. BY 00Z (8 PM EDT) SATURDAY...MOST MODELS
SHOW THE COLD FRONT STILL WEST OF OUR FORECAST AREA. THE POTENTIAL
EXISTS FOR STRONG TO SEVERE STORMS TO ERUPT IN ADVANCE OF THIS
SYSTEM AS THE AREA COMES UNDER THE INFLUENCE OF THE RR QUAD OF AN
UPPER LEVEL JET ROTATING AROUND THE EASTERN SIDE OF THE APPROACHING
SHORT WAVE TROF. THE BIGGEST QUESTION CONCERNING THE POTENTIAL FOR
SEVERE WEATHER WILL BE THE INSTABILITY. CLOUDS ON FRIDAY SHOULD KEEP
HIGH TEMPS BELOW THURSDAY`S EXPECTED HIGHS AND MAY KEEP INSTABILITY
DOWN. THE GFS CRAVEN SIG SVR PARAMETER FORECAST KEEPS THE HIGHEST
POTENTIAL FOR SEVERE WEATHER TO OUR SOUTHEAST...WHERE INSTABILITY IS
FORECAST TO BE HIGHER. CONSIDERING THE STRENGTH OF THIS UPPER LEVEL
SYSTEM...WILL KEEP MENTION OF SVR WX IN THE HWO...ALONG WITH THE
THREAT FOR HEAVY RAIN WITH PWATS EXPECTED TO EXCEED 2 INCHES IN THE
EAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 242 PM EDT TUESDAY...
THE LONG RANGE MODELS ARE IN GOOD AGREEMENT THAT THE EASTERN U.S.
REMAINS UNDER THE INFLUENCE OF AN UPPER TROF THAT DE-AMPLIFIES WITH
TIME. AHEAD OF THE UPPER TROF...A STRONG COLD FRONT WILL SWEEP
THROUGH FRIDAY NIGHT. THE 00Z ECMWF HOLDS MORE UPPER LEVEL ENERGY ON
THE WEST SIDE OF THE UPPER TROF AND KEEPS PRECIP LINGERING IN THE
FAR EASTERN PORTION OF OUR FORECAST AREA ON SATURDAY. SO WE HAVE
DELAYED THE ENDING TIME OF THE PRECIP UNTIL MIDDAY SATURDAY.
OTHERWISE...UPSLOPE RAIN SHOWERS CAN BE EXPECTED UNDER THE TROF AXIS
AND LOW LEVEL NORTHWEST WINDS.
DRIER...COOLER AND LESS HUMID AIR WILL INVADE THE REGION LATE
SATURDAY INTO SUNDAY. THE GEFS SHOWS 850MB TEMPS BY 18Z SATURDAY
WILL BE 1-2 STANDARD DEVIATIONS BELOW NORMAL. SO...LEANED TOWARD THE
COOLER ECMWF VALUES FOR TEMPS SATURDAY NIGHT THROUGH SUNDAY NIGHT.
TEMPERATURES WILL GRADUALLY WARM MONDAY AND TUESDAY AS THE UPPER
LEVEL TROF RELAXES...BUT INDIVIDUAL SHORT WAVES MOVING THROUGH AN
UPPER LEVEL NORTHWEST FLOW COMBINED WITH A WEAK SOUTHEAST FLOW WILL
GENERATE AFTERNOON SHOWERS AND STORMS.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
AS OF 132 PM EDT TUESDAY...
MAINLY VFR CONDITIONS EXIST ALONG AND NORTH OF KBLF-KFCX LINE THIS
AFTERNOON...WITH PATCHY MVFR CIGS SOUTH OF THIS LINE. EXPECTING
CIGS TO TREND TO VFR AT ALL LOCATIONS BY LATE THIS AFTERNOON.
ISOLATED SHOWERS AND STORMS ALSO POSSIBLE MAINLY ALONG AND SOUTH
OF THE NC/VA BORDER THROUGH THE AFTERNOON. TONIGHT...ISOLATED
CONVECTION WILL CONTINUE INTO THE EVENING. MANY AREAS WILL SEE
VALLEY AND RIVER FOG DEVELOPING OVERNIGHT...WITH MOSTS AREAS MVFR
FOR VSBYS BY SURNISE WITH ISOLATED IFR OR LOWER. VLIFR/LIFR CIGS
AREA ALSO POSSIBLE WITHIN THE VALLEYS. ANY SUB-VFR CONDITIONS
SHOULD IMPROVE TO VFR BY 13-14Z...9-10AM...WEDNESDAY
A FRONTAL BOUNDARY WILL HOVER AROUND THE REGION THROUGH THE
WEEKEND WITH PERIODIC WAVES OF ENERGY RIDING ALONG IT. LOOK FOR AT
LEAST ISOLATED DIURNAL CONVECTION DURING THIS TIME PERIOD...WITH
FRIDAY INTO SATURDAY HAVING A BETTER CHANCE OF ORGANIZED
CONVECTION AS A LOW DEVELOPS OVER THE MIDWEST AND EJECTS THE FRONT
EASTWARD AS A STRONG COLD FRONT. LATE NIGHT/EARLY MORNING MOUNTAIN
AND RIVER VALLY FOG IS ALSO EXPECTED MOST NIGHTS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS
SHORT TERM...PH
LONG TERM...PH
AVIATION...DS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
300 PM EDT TUE AUG 7 2012
.SYNOPSIS...
A PERIOD OF UNSETTLED WEATHER WILL CONTINUE THIS WEEK AS A FRONTAL
BOUNDARY OSCILATES ACROSS THE MID ATLANTIC REGION. A STRONG COLD
FRONT WILL SWEEP ACROSS THE REGION ON FRIDAY...BRINGING A GENEROUS
COVERAGE OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER
AND DRIER WEATHER IS EXPECTED BY THE START OF THE NEXT WEEK AS
HIGH PRESSURE BUILDS INTO THE REGION.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 233 PM EDT TUESDAY...
A FRONTAL BOUNDARY WAS SLOWLY HEADING SOUTH THROUGH THE REGION. THE
FRONT...ALONG WITH DAYTIME HEATING...IS HELPING ISOLATED SHOWERS TO
DEVELOP THIS AFTERNOON NEAR THE CREST OF THE BLUE RIDGE FROM ROUGHLY
FLOYD VA...SOUTHWEST INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA.
OTHER ISOLATED SHOWERS WERE OVER PARTS OF THE MOUNTAIN EMPIRE REGION
OF SOUTHWEST VIRGINIA AND SOUTHSIDE VIRGINIA. THESE ARE EXPECTED TO
CONTINUE THROUGH THE AFTERNOON...AND PERHAPS INCREASE IN COVERAGE
AND GAIN A FEW STRIKES OF LIGHTNING. THIS FRONT WILL CONTINUE TO
SLOWLY HEAD SOUTH THROUGH THE NIGHT...SO THAT HIGH PRESSURE WILL BE
NOSING SOUTH INTO THE REGION BY WEDNESDAY.
THIS HIGH WILL BRING A TREND TOWARDS DECREASING CLOUDS OVERNIGHT
INTO EARLY WEDNESDAY MORNING. LIGHT WINDS...AND LINGERING BOUNDARY
LAYER MOISTURE BELOW THE NOCTURNAL INVERSION WILL HELP GENERATE
AREAS OF FOG TONIGHT ACROSS A GENEROUS PORTION OF THE AREA. WHILE
THERE IS BOUND TO BE SOME DENSE FOG...CONFIDENCE IN IT BEING
WIDESPREAD ARE NOT HIGH AT THIS TIME. WILL HIGHLIGHT THE POTENTIAL
FOR SOME DENSE FOG TONIGHT IN ALL BUT THE BLUEFIELD TO TAZEWELL
AREA. LOW TEMPERATURES TONIGHT WILL AVERAGE THREE TO FIVE DEGREES
COOLER THAN READINGS EXPERIENCED THIS MORNING.
ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR AS
PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH.
HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE
LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED SHOWERS
SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING FARTHER TO OUR
SOUTH...MORE SUNSHINE SHOULD YIELD HIGH TEMPERATURES ON WEDNESDAY
ABOUT THREE TO FIVE DEGREES WARMER THAN TODAY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 242 PM EDT TUESDAY...
CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE SHORT TERM
PERIOD AS AN UPPER LEVEL TROF AMPLIFIES OVER THE GREAT LAKES AND
INTO THE OHIO VALLEY BY FRIDAY.
IN ADVANCE OF THIS SYSTEM...TEMPERATURES SHOULD WARM TOWARD THE
WARMER NAM MOS VALUES ON THURSDAY AS THE LOW LEVEL THERMAL RIDGE
NOSES INTO OUR AREA. BEST CHANCES FOR THUNDERSTORMS ON THURSDAY WILL
BE IN THE WEST AS A LEAD SHORT WAVE (OVERDONE BY THE GFS) APPROACHES
OUR AREA AND INTERACTS WITH A MODERATELY UNSTABLE AIRMASS. KEPT POPS
IN THE EASTERN PORTION OF THE FORECAST AREA ON THURSDAY AS WEAK LOW
LEVEL CONVERGENCE ALONG A LEE-SIDE TROF SHOULD GENERATE SCATTERED
CONVECTION.
THIS CONVECTION MAY LINGER A FEW HOURS BEYOND SUNDOWN THURSDAY NIGHT
WITH SUPPORT FROM THE WEAK UPPER LEVEL WAVE MOVING THROUGH.
THE TREND OF THE MODELS FOR FRIDAY`S SYSTEM HAS BEEN TO SLOW ITS
EASTWARD PROGRESS SLIGHTLY. BY 00Z (8 PM EDT) SATURDAY...MOST MODELS
SHOW THE COLD FRONT STILL WEST OF OUR FORECAST AREA. THE POTENTIAL
EXISTS FOR STRONG TO SEVERE STORMS TO ERUPT IN ADVANCE OF THIS
SYSTEM AS THE AREA COMES UNDER THE INFLUENCE OF THE RR QUAD OF AN
UPPER LEVEL JET ROTATING AROUND THE EASTERN SIDE OF THE APPROACHING
SHORT WAVE TROF. THE BIGGEST QUESTION CONCERNING THE POTENTIAL FOR
SEVERE WEATHER WILL BE THE INSTABILITY. CLOUDS ON FRIDAY SHOULD KEEP
HIGH TEMPS BELOW THURSDAY`S EXPECTED HIGHS AND MAY KEEP INSTABILITY
DOWN. THE GFS CRAVEN SIG SVR PARAMETER FORECAST KEEPS THE HIGHEST
POTENTIAL FOR SEVERE WEATHER TO OUR SOUTHEAST...WHERE INSTABILITY IS
FORECAST TO BE HIGHER. CONSIDERING THE STRENGTH OF THIS UPPER LEVEL
SYSTEM...WILL KEEP MENTION OF SVR WX IN THE HWO...ALONG WITH THE
THREAT FOR HEAVY RAIN WITH PWATS EXPECTED TO EXCEED 2 INCHES IN THE
EAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 242 PM EDT TUESDAY...AS OF 233 PM EDT TUESDAY...
A FRONTAL BOUNDARY WAS SLOWLY HEADING SOUTH THROUGH THE REGION. THE
FRONT...ALONG WITH DAYTIME HEATING...IS HELPING ISOLATED SHOWERS TO
DEVELOP THIS AFTERNOON NEAR THE CREST OF THE BLUE RIDGE FROM ROUGHLY
FLOYD VA...SOUTHWEST INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA.
OTHER ISOLATED SHOWERS WERE OVER PARTS OF THE MOUNTAIN EMPIRE REGION
OF SOUTHWEST VIRGINIA AND SOUTHSIDE VIRGINIA. THESE ARE EXPECTED TO
CONTINUE THROUGH THE AFTERNOON...AND PERHAPS INCREASE IN COVERAGE
AND GAIN A FEW STRIKES OF LIGHTNING. THIS FRONT WILL CONTINUE TO
SLOWLY HEAD SOUTH THROUGH THE NIGHT...SO THAT HIGH PRESSURE WILL BE
NOSING SOUTH INTO THE REGION BY WEDNESDAY.
THIS HIGH WILL BRING A TREND TOWARDS DECREASING CLOUDS OVERNIGHT
INTO EARLY WEDNESDAY MORNING. LIGHT WINDS...AND LINGERING BOUNDARY
LAYER MOISTURE BELOW THE NOCTURNAL INVERSION WILL HELP GENERATE
AREAS OF FOG TONIGHT ACROSS A GENEROUS PORTION OF THE AREA. WHILE
THERE IS BOUND TO BE SOME DENSE FOG...CONFIDENCE IN IT BEING
WIDESPREAD ARE NOT HIGH AT THIS TIME. WILL HIGHLIGHT THE POTENTIAL
FOR SOME DENSE FOG TONIGHT IN ALL BUT THE BLUEFIELD TO TAZEWELL
AREA. LOW TEMPERATURES TONIGHT WILL AVERAGE THREE TO FIVE DEGREES
COOLER THAN READINGS EXPERIENCED THIS MORNING.
ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR AS
PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH.
HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE
LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED SHOWERS
SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING FARTHER TO OUR
SOUTH...MORE SUNSHINE SHOULD YIELD HIGH TEMPERATURES ON WEDNESDAY
ABOUT THREE TO FIVE DEGREES WARMER THAN TODAY.
THE LONG RANGE MODELS ARE IN GOOD AGREEMENT THAT THE EASTERN U.S.
REMAINS UNDER THE INFLUENCE OF AN UPPER TROF THAT DE-AMPLIFIES WITH
TIME. AHEAD OF THE UPPER TROF...A STRONG COLD FRONT WILL SWEEP
THROUGH FRIDAY NIGHT. THE 00Z ECMWF HOLDS MORE UPPER LEVEL ENERGY ON
THE WEST SIDE OF THE UPPER TROF AND KEEPS PRECIP LINGERING IN THE
FAR EASTERN PORTION OF OUR FORECAST AREA ON SATURDAY. SO WE HAVE
DELAYED THE ENDING TIME OF THE PRECIP UNTIL MIDDAY SATURDAY.
OTHERWISE...UPSLOPE RAIN SHOWERS CAN BE EXPECTED UNDER THE TROF AXIS
AND LOW LEVEL NORTHWEST WINDS.
DRIER...COOLER AND LESS HUMID AIR WILL INVADE THE REGION LATE
SATURDAY INTO SUNDAY. THE GEFS SHOWS 850MB TEMPS BY 18Z SATURDAY
WILL BE 1-2 STANDARD DEVIATIONS BELOW NORMAL. SO...LEANED TOWARD THE
COOLER ECMWF VALUES FOR TEMPS SATURDAY NIGHT THROUGH SUNDAY NIGHT.
TEMPERATURES WILL GRADUALLY WARM MONDAY AND TUESDAY AS THE UPPER
LEVEL TROF RELAXES...BUT INDIVIDUAL SHORT WAVES MOVING THROUGH AN
UPPER LEVEL NORTHWEST FLOW COMBINED WITH A WEAK SOUTHEAST FLOW WILL
GENERATE AFTERNOON SHOWERS AND STORMS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
AS OF 132 PM EDT TUESDAY...
MAINLY VFR CONDITIONS EXIST ALONG AND NORTH OF KBLF-KFCX LINE THIS
AFTERNOON...WITH PATCHY MVFR CIGS SOUTH OF THIS LINE. EXPECTING
CIGS TO TREND TO VFR AT ALL LOCATIONS BY LATE THIS AFTERNOON.
ISOLATED SHOWERS AND STORMS ALSO POSSIBLE MAINLY ALONG AND SOUTH
OF THE NC/VA BORDER THROUGH THE AFTERNOON. TONIGHT...ISOLATED
CONVECTION WILL CONTINUE INTO THE EVENING. MANY AREAS WILL SEE
VALLEY AND RIVER FOG DEVELOPING OVERNIGHT...WITH MOSTS AREAS MVFR
FOR VSBYS BY SURNISE WITH ISOLATED IFR OR LOWER. VLIFR/LIFR CIGS
AREA ALSO POSSIBLE WITHIN THE VALLEYS. ANY SUB-VFR CONDITIONS
SHOULD IMPROVE TO VFR BY 13-14Z...9-10AM...WEDNESDAY
A FRONTAL BOUNDARY WILL HOVER AROUND THE REGION THROUGH THE
WEEKEND WITH PERIODIC WAVES OF ENERGY RIDING ALONG IT. LOOK FOR AT
LEAST ISOLATED DIURNAL CONVECTION DURING THIS TIME PERIOD...WITH
FRIDAY INTO SATURDAY HAVING A BETTER CHANCE OF ORGANIZED
CONVECTION AS A LOW DEVELOPS OVER THE MIDWEST AND EJECTS THE FRONT
EASTWARD AS A STRONG COLD FRONT. LATE NIGHT/EARLY MORNING MOUNTAIN
AND RIVER VALLY FOG IS ALSO EXPECTED MOST NIGHTS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS
SHORT TERM...PH
LONG TERM...PH
AVIATION...DS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
305 AM CDT TUE AUG 7 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
305 AM CDT TUE AUG 7 2012
MAIN CONCERN DEALS WITH FRONTAL PASSAGE THIS MORNING ALONG WITH ANY
SHOWER/THUNDER CHANCES...THEN SHOWER/THUNDER CHANCES AGAIN WEDNESDAY
THROUGH THURSDAY EVENING.
CURRENTLY MONITORING A COLD FRONT MOVING SOUTH ACROSS UPPER
MI/NORTHERN WI. RADAR SHOWING MAIN SHRA/TS ACTIVITY CONFINED ACROSS
NORTHEAST WI THROUGH CENTRAL/EASTERN UPPER MICHIGAN. OTHERWISE...
SKIES AT 3 AM WERE MOSTLY CLEAR ACROSS THE AREA WITH TEMPERATURES
RANGING FROM THE UPPER 50S TO MIDDLE 60S.
07.00Z MODELS IN VERY GOOD AGREEMENT THROUGH THE SHORT TERM WITH
HANDLING OF OVERALL SYNOPTIC PATTERN.
FOR TODAY...WILL BE WATCHING THAT COLD FRONT CONTINUE MOVING SOUTH
THROUGH THE AREA...EXITING BY NOON. MODEL SOUNDINGS SHOWING VERY
HIGH-BASED ACCAS ASSOCIATED WITH THE FRONT AS IT PASSES
THROUGH...LENDING TO EVAPORATION BEFORE THE RAIN REACHES THE GROUND.
WILL CONTINUE A SLIGHT CHANCE OF SHRA/TS THIS MORNING SOUTH OF A
RICHLAND CENTER/PRAIRIE DU CHIEN WI...TO CHARLES CITY IA LINE WHERE
BETTER 850MB MOISTURE TRANSPORT/CONVERGENCE WILL RESIDE.
OTHERWISE...PLAN ON DRYING THIS AFTERNOON AS THE FRONT SLIPS SOUTH
OF THE AREA AND HIGH PRESSURE BUILDS SOUTH OUT OF MN. HIGHS TODAY
ARE EXPECTED TO BE IN THE 80S.
MOSTLY CLEAR SKIES THIS EVENING WILL GIVE WAY TO INCREASING MID/HIGH
CLOUDS LATE TONIGHT AHEAD OF AN APPROACHING MID-LEVEL SHORTWAVE
TROUGH DROPPING SOUTHEAST THROUGH THE DAKOTAS. APPEARS ANY SHRA/TS
ACTIVITY WILL STAY WEST OF THE AREA AS DRIER AIR ASSOCIATED WITH THE
HIGH HOLDS IN PLACE OVER THE FORECAST AREA.
FOR WEDNESDAY THROUGH THURSDAY WILL BE WATCHING THE MID-LEVEL
SHORTWAVE TROUGH MOVE SOUTHEAST INTO THE AREA WHILE A DEEPER/MORE
VIGOROUS TROUGH ROTATES SOUTH OUT OF CANADA. COLDER/CYCLONIC FLOW
ALOFT WILL COMBINE WITH DAYTIME SURFACE HEATING TO PRODUCE 0-3KM
MUCAPE IN THE 500-1000J/KG FOR SHRA/TS CHANCES. WITH CLOUD
COVER/SCATTERED CONVECTION/COLD AIR ALOFT...PLAN ON TEMPERATURES
THURSDAY ONLY TOPPING OFF IN THE UPPER 60S TO MIDDLE 70S. LOOK FOR
THE TROUGH TO ROTATE SOUTHEAST OF THE AREA THURSDAY NIGHT BRINGING
AN END TO SHRA/TS CHANCES.
.LONG TERM...FRIDAY THROUGH MONDAY
305 AM CDT TUE AUG 7 2012
LATEST GFS/ECMWF SHOW A RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA
ON FRIDAY...HOLDING THROUGH SATURDAY FOR A BOUT OF QUIET/DRY WEATHER
WITH HIGH TEMPERATURES IN THE 70S. MODELS SHOW A WEAK MID-LEVEL WAVE
COMING THROUGH THE RIDGE ON SUNDAY. THIS IS EXPECTED TO SPREAD A FEW
CLOUDS INTO THE AREA...BUT EXPECTED TO REMAIN DRY. GFS/ECMWF THEN
SHOW SOME DIFFERENCES ON MONDAY WITH THE GFS WANTING TO BRING
ANOTHER MID-LEVEL WAVE FARTHER SOUTH INTO THE AREA WHILE THE ECMWF
IS MUCH WEAKER AND FARTHER NORTH INTO CANADA. CONSENSUS OF THE MODEL
YIELDS A DRY MONDAY WITH HIGHS IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION...THROUGH 18Z TUESDAY
1100 PM CDT MON AUG 6 2012
VERY DRY 00Z SOUNDINGS FROM MSP/GRB/DVN...WITH LITTLE TO NO CLOUDS
INDICATED IN THE VICINITY FROM LATEST CLOUD/STRATUS SATELLITE
IMAGERY. OTHER THEN A FEW MID LEVEL CLOUDS...THE BULK OF WHAT WAS
OUT THERE WAS CONFINED AROUND A FRONTAL BOUNDARY ACROSS NORTHEAST
MN/UP OF MICH. RAP STILL ADAMANT WITH ABOUT 1000 J/KG OF MLCAPE
ACROSS THE AREA FOR MUCH OF THE OVERNIGHT...WITH SOME FRONTOGENETIC
FORCING...AND A GOOD PUSH OF 925 MB MOISTURE ADVECTION. THAT FRONT
TO THE NORTH WILL DROP SOUTH OVERNIGHT...LIKELY SLIPPING SOUTH OF
KRST/KLSE AROUND 12Z...AND THERE IS A WEAK SHORTWAVE MAKING ITS WAY
SOUTHEAST ACROSS THE REGION. SO...THERE ARE FORCING MECHANISMS...BUT
SATURATION PER THE SOUNDINGS AND FORECAST RH FIELDS/BUFKIT SOUNDINGS
PRETTY MEAGER. IF SHRA/TS WOULD DEVELOP...BASES WOULD PROBABLY BE
AOA 8 KFT. CONFIDENCE LOW ENOUGH THAT I HAVE REMOVED THE VCSH FROM
THE TAFS. IF THEY DO DEVELOP...DON/T BELIEVE THERE WOULD BE ANY
CIG/VSBY IMPACT. PERHAPS SOME GUSTINESS.
AS FOR VSBY...WITH SKIES MORE SKC/SCT OVERNIGHT AND THE SFC WIND
FIELD VRB/CALM ACROSS MUCH OF THE AREA...RIVER VALLEY FOG IS A
CONCERN. T/TD SPREAD THE SAME AS YESTERDAY AT 03Z AT KLSE...8
DEGREES. WINDS AREN/T PROGGED TO BE AS LIGHT OFF THE SFC
THOUGH...WITH RAP/NAM12 BUFKIT SOUNDINGS AROUND 10-15 KTS BY 200-400
HUNDRED FEET. TDS HAVE CONTINUED TO CLIMB THIS EVENING...AND MIGHT
GET ANOTHER 1-2 DEGREE RISE. THIS COULD BE ALL THAT IS NEEDED FOR
IFR FG AT KLSE. HAVE DECIDE TO TREND THE FORECAST MUCH LIKE MONDAY
MORNING...WITH 2SM...AND BCFG TO COVER THE PATCHES OF MORE DENSE
FOG. CONDITIONS WILL BE MONITORED AND ADJUSTMENTS MADE AS A
NEEDED.
WITH THE FRONT SLIDING THROUGH EARLY TUE MORNING...WINDS WILL SWITCH
TO THE NORTHWEST. HIGH PRESSURE WILL FOLLOW IN ITS WAKE...WITH QUIET
VFR CONDITIONS THEN INTO TUE NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 AM CDT TUE AUG 7 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
337 AM EDT THU AUG 9 2012
.DISCUSSION...
TODAY-TONIGHT...
CENTRAL FL IS UNDER THE DIRECT INFLUENCE OF A MID/UPR LVL COL AS
SEEN BY THE LATEST RAP ANALYSIS OF THE H85-H50 AND H30-H20
STREAMLINES. THE RESULTING STEERING FLOW IS QUITE WEAK AND HOLDS
LITTLE POTENTIAL FOR PUSHING ANY SIG MID LVL ENERGY INTO THE TORPID
AIRMASS THAT CURRENTLY BLANKETS THE CWA: BOTH THE H85-H50 AND
H85-H30 VORTICITY FIELDS SHOW MINIMAL LIFT POTENTIAL.
LOW AND MID LVL MOISTURE TRAPPED UNDERNEATH THE COL WITH H100-H70
AND H85-H50 MEAN RH VALUES LARGELY ABV 75PCT OVR THE NW HALF OF THE
CWA. MID LVL THERMAL RIDGE HAS WEAKENED A TOUCH OVER THE PAST 24HRS
THOUGH H70 TEMPS REMAIN ON THE ORDER OF 9C. COMBINED WITH H50 TEMPS
BTWN -6C AND -7C...THE MID LVL LAPSE RATES ARE MODERATELY UNSTABLE
AT BEST. A 50KT H30-H20 JET STREAK LIFTING UP THE ERN SEABOARD WILL
GENERATE WEAK UPR LVL DIVERGENCE N OF THE CAPE THIS MORNING...BUT
THIS WILL DIMINISH THRU THE DAY AS THE JET PULLS AWAY FROM THE FL
PENINSULA.
THE CURRENT WX PATTERN IS TYPICAL OF MID SUMMER...THOUGH LINGERING
DRY AIR OVER THE SE HALF OF THE CWA WILL RESULT IN BLO AVG PRECIP
COVERAGE. MESOSCALE BNDRY INTERACTION ONCE AGAIN WILL BE REQUIRED TO
SPARK DIURNAL CONVECTION. ISOLD COVERAGE OVER THE SE HALF OF THE CWA
DUE TO DRIER AIR AND EARLIER FORMATION OF THE EAST COAST SEA
BREEZE...SCT COVERAGE INTERIOR DUE TO DEEPER MOISTURE AND WARMER MAX
TEMPS. MOST OF THE ACTIVITY WILL BURN OUT BY SUNSET. WILL KEEP ISOLD
TSRAS THRU MID EVENING OVR THE NRN CWA TO ACCOUNT FOR LINGERING
POCKETS OF ENERGY.
MAV MOS TEMPS CONTINUE ON THE HIGH SIDE GIVE THE MID/UPR LVL
MOISTURE BAND AND EARLY FORMATION OF THE SEA BREEZE...WILL CONTINUE
TO KEEP MAX TEMPS IN THE U80S/L90S ALONG THE COAST AND L/M90S
INTERIOR. LIGHT SRLY BREEZE WILL KEEP MIN TEMPS IN THE L/M70S.
FRI-SAT...LITTLE CHANGE FROM PREVIOUS GFS RUNS IS INDICATED.
UPPER LEVEL INVERTED TROUGH WILL PUSH WEST OF THE AREA/WEAKEN ON
FRI. THIS WILL CAUSE SUBSIDENCE TO DIMINISH. THEN ON SAT THE TAIL
END OF A TROUGH IN THE WESTERLIES WILL NOSE INTO THE EASTERN GULF
OF MEXICO...WHICH IS USUALLY A FAVORABLE SYNOPTIC PATTERN FOR
INCREASED POPS.
SOUTHEAST LOW LEVEL FLOW WILL START TO TAP HIGHER MOISTURE ON FRI
SO POPS WILL RETURN TO SCATTERED ACROSS THE AREA. THE HIGHEST
VALUES SHOULD BE OVER THE SOUTH WHERE DEEPEST MOISTURE IS PROGGED.
ON SAT AROUND 2 INCHES OF PRECIPITABLE WATER IS INDICATED AREAWIDE.
WITH THE TROUGH ALOFT MOVING ACROSS THE SOUTHEAST STATES THERE
SHOULD BE SOME WESTERLY STEERING LEVEL FLOW...ALBEIT RATHER WEAK. SO
POPS WILL BE AT LEAST 40 PERCENT AREAWIDE. GREATER BOUNDARY
INTERACTIONS ACROSS THE SOUTH SHOULD CAUSE HIGHER VALUES AROUND 50
PERCENT. THESE VALUES ARE CLOSE TO THE LATEST MOS. NOT CONFIDENT
ENOUGH IN THE MODEL HANDLING OF MOISTURE TO GO HIGHER ON POPS YET.
SUN-THU...GFS INDICATES TROUGHING ALOFT OVER THE EASTERN PART OF
THE COUNTRY WITH ASSOCIATED SURFACE FRONTAL TROUGH KEEPING SURFACE
RIDGE ACROSS THE CENTRAL TO SOUTH CENTRAL FLORIDA PENINSULA. THIS
SHOULD ALLOW A WEAK WESTERLY STEERING FLOW TO CONTINUE ACROSS THE
AREA FOR MOST OF THE PERIOD. NEAR TO A LITTLE ABOVE NORMAL
PRECIPITABLE WATER IS INDICATED. WITH 700 MB TEMPS REMAINING 9 TO
10 DEGREES CELSIUS...AGREE WITH MOS POPS WHICH REMAIN AT OR A
LITTLE BELOW CLIMO...30 TO 40 PERCENT.
WITH CONVECTION LIKELY TO INITIATE A LITTLE LATER THAN NORMAL...MAX
TEMPS WILL CONTINUE A FEW DEGREES HOTTER THAN NORMAL...WITH 90 TO
LOWER 90S ALONG THE COAST AND MID 90S INLAND.
&&
.AVIATION...
ALL SITES VFR UNLESS OTHERWISE NOTED: THRU 09/13Z...LCL MVFR
CIGS/IFR VSBYS IN BR CSTL SITES S OF KMLB. BTWN 09/15Z-09/17Z...
DVLPMNT OF THE EAST COAST SEA BREEZE S OF KTIX WILL FORCE A SFC
WNDSHFT FM S/SE TO E AOB 10KTS...SEA BREEZE WILL WORK ITS WAY UP THE
COAST N OF KTIX THRU MID AFTN...FORCING A WNDSHFT FM S/SW TO SE.
BTWN 08/18Z-08/24Z...SCT MVFR SHRAS/IFR TSRAS N OF KISM-KTIX...ISOLD
MVFR SHRAS/IFR TSRAS S OF KISM-KTIX.
&&
.MARINE...
TODAY-TONIGHT...ATLC RIDGE AXIS BISECTING THE FL PENINSULA WILL
GENERATE A GENTLE TO MODERATE S/SE BREEZE S OF CAPE CANAVERAL...S/SW
N OF CAPE CANAVERAL. THE EAST COAST SEA BREEZE WILL FORM BY MIDDAY S
OF THE CAPE...FORCING SFC/BNDRY LYR WNDS NEAR THE COAST TO BACK TO
THE E. SEA BREEZE WILL DVLP NWD THRU MID AFTN WITH WINDS BACKING TO
THE SE BTWN THE CAPE AND FLAGLER BEACH. SEAS AOB 2FT NEARSHORE AND
2-3FT OFFSHORE. SCT AFTN TSRAS MOVG OFFSHORE N OF THE CAPE.
FRI-MON...THE ATLANTIC SURFACE RIDGE AXIS IS PROGGED TO EXTEND
ACROSS THE CENTRAL TO SOUTH CENTRAL PENINSULA. THIS WILL CONTINUE
THE SOUTHWEST TO SOUTH/SOUTHEAST WIND FLOW WITH SPEEDS 10 KNOTS
OR LESS...EXPECT FOR A SLIGHT INCREASE TO 10-15 KNOTS FRI EVENING.
INCREASING MOISTURE AND A WEAK WESTERLY STEERING LEVEL WIND FLOW
SHOULD BRING SOME OF THE AFTERNOON/EVENING STORMS BACK ACROSS THE
COAST AND INTO THE NEAR SHORE ATLANTIC ON MOST OF THE DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 90 75 92 74 / 30 20 30 20
MCO 93 76 94 74 / 30 20 30 20
MLB 89 76 90 74 / 20 10 30 20
VRB 91 74 90 74 / 20 10 40 30
LEE 92 77 95 75 / 30 20 30 20
SFB 93 77 94 75 / 30 20 30 20
ORL 93 76 94 76 / 30 20 30 20
FPR 91 74 90 73 / 20 10 40 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
426 AM EDT THU AUG 9 2012
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL REMAIN OFFSHORE THROUGH LATE WEEK...WHILE
A WEAK TROUGH OF LOW PRESSURE PERSISTS INLAND. A STRONG LOW PRESSURE
SYSTEM WILL DEVELOP TO THE NORTH ON FRIDAY...WHILE AN ASSOCIATED
COLD FRONT APPROACHES OVER THE WEEKEND. THE FRONT WILL LIKELY STALL
OVER OR NEAR THE AREA...BEFORE DISSIPATING BY THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE-DAWN...OVERNIGHT WE HAVE BEEN WATCHING AN E-W BOUNDARY MAINTAIN
CONVECTION JUST OFFSHORE. THIS BOUNDARY EXTRAPOLATES THROUGH THE
SAVANNAH RIVER BUT ONLY SPOTTY LAND BASED SHOWERS DESPITE SOME
DECENT INSTABILITY NOTED ON THE SPC RUC MESO ANALYSIS AT 08Z.
UPSTREAM CONVECTION OVER THE CSRA AND S CAROLINA UPSTATE IN
RESPONSE TO A WEAK SHORT WAVE AND A REGION OF UPPER DIVERGENCE.
CANNOT RULE OUT AN ISOLATED SHOWER OR STORM ACROSS THE FORECAST
AREA BUT MOST AREAS TO START THE DAY DRY. SOME AREAS WILL SEE
PATCHY FOG WITH TEMPS AND DEW POINTS EQUIVALENT AND LOW LEVELS
SATURATED.
TODAY...A WEAK MID/UPPER TROUGH LINGERS ACROSS THE REGION WITH
ATMOSPHERIC MOISTURE AND STABILITY PROFILES FAIRLY TYPICAL FOR
THIS TIME OF YEAR. LAST NIGHT/S CONVECTION OVER THE SE MIDLANDS
PUSHED A FAIRLY SUBSTANTIAL OUTFLOW BOUNDARY INTO INLAND AREAS TO
THE NW OF BEAUFORT AND W OF CHARLESTON AND THE OTHER BOUNDARY IN
SE GEORGIA UNLIKELY TO MOVE MUCH TODAY. DIFFERENTIAL HEATING THIS
MORNING AND PRESENCE OF SMALL SCALE BOUNDARIES SHOULD MAKE FOR
SOME FAIR DESTABILIZATION THIS AFTERNOON WITH PULSE CONVECTION
BECOMING SCATTERED TO THE W OF I-95 AND MAINLY ISOLATED ALONG
COASTAL SOUTH CAROLINA. SATELLITE IMAGERY SHOWS BETTER CHANCES FOR
SOME MORNING SUNSHINE MANY AREAS AND THIS SHOULD RESULT IN WARMER
TEMPS 89-92 DEGREES TODAY BEFORE SHOWERS AND STORMS INITIATE. BEST
INSTABILITY PARAMETERS SUGGEST STRONGER TSTMS WILL END UP OVER
INLAND AREAS MAINLY ALONG AND W OF I-95 AND PROBABLY N OF I-16.
ISOLATED SEVERE WEATHER MAY BE POSSIBLE LOCALLY WITH DOWNDRAFT
CAPES OVER 1000 J/KG TO START THE DAY TO THE N OF I-16. STEERING
FLOW WILL BE INITIALLY BE SLUGGISH ACROSS THE AREA. TO THE S OF
I-16...PWATS ARE HIGHER AND CONVECTIVE INITIATION WILL LIKELY
OCCUR SOMEWHAT EARLIER IN THE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
MODELS IN GOOD AGREEMENT ON DRIVING A FAIRLY SIGNIFICANT MID LEVEL
TROUGH INTO THE GEORGIA AND THE CAROLINAS TONIGHT AND THIS FEATURE
WILL LIKELY MAINTAIN SCATTERED CONVECTIVE RAINS ACROSS THE
FORECAST AREA THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS.
WEAK HEIGHT FALLS SUGGEST CONVECTION COULD REMAIN STRONG INLAND IN
MULTICELL CLUSTERS WITH SCATTERED SHOWERS AND TSTMS DEVELOPING TOWARD
COASTAL AREAS OVERNIGHT... ESPECIALLY IF AIR MASS GOES UNTAPPED
FROM SEA BREEZE CONVECTION THIS AFTERNOON.
FRIDAY AND SATURDAY...A STRONG UPPER LOW SYSTEM WILL ROTATE INTO
THE OHIO VALLEY REGION ON FRIDAY...PROVIDING THE NECESSARY ENERGY
TO DEVELOP AN UNSEASONABLY STRONG CO-LOCATED SURFACE LOW. THE
STACKED LOW SYSTEM WILL SLOWLY MEANDER FARTHER TO THE
NORTH/NORTHEAST FRIDAY INTO SATURDAY...WHILE THE UPPER TROUGH
STRETCHING DOWN THE EAST COAST AMPLIFIES ACCORDINGLY. A TRAILING
COLD FRONT WILL MAKE STEADY PROGRESS TOWARD THE COASTLINE THROUGH
THE DAYTIME HOURS SATURDAY...AIDED BY A SERIES OF SHORTWAVES
DOWNSTREAM OF THE TROUGH AXIS JUST TO THE WEST. UPPER LEVEL
SUPPORT WITHIN THE RIGHT REAR ENTRANCE OF A STRENGTHENING UPPER
JET...COMBINED WITH SHORTWAVE ENERGY AND LOW LEVEL CONVERGENCE
FROM THE APPROACHING COLD FRONT...WILL ENHANCE DEEP MOISTURE
ACROSS THE REGION. AS A RESULT...SHOWER/THUNDERSTORM POTENTIAL
WILL INCREASE FRIDAY AND SATURDAY. WILL CONTINUE TO ADVERTISE MOST
SIGNIFICANT CONVECTIVE COVERAGE ON SATURDAY...WHEN THE FRONT WILL
BE CLOSEST TO THE FORECAST AREA AND UPPER LEVEL SUPPORT WILL BE
MAXIMIZED. HAVE INDICATED POPS GENERALLY IN THE 40 PERCENT RANGE
FRIDAY AND FRIDAY NIGHT...INCREASING TO AROUND 50 PERCENT BY
SATURDAY. CONSIDERING THE UNSEASONABLY STRONG SYNOPTIC LEVEL
FEATURES AT BOTH THE SURFACE AND ALOFT...AS WELL AS TYPICAL
SUMMERTIME HEATING AND INSTABILITY...WILL NEED TO MONITOR MODEL
TRENDS AND STORM PREDICTION CENTER OUTLOOKS FOR SEVERE WEATHER
POTENTIAL.
HIGH TEMPERATURES FRIDAY AND SATURDAY WILL BE SUPPRESSED SLIGHTLY
BY THICKENING CLOUD COVER AND DECREASING HEIGHTS ALOFT. EXPECT
TEMPERATURES TO PEAK IN THE UPPER 80S TO AROUND 90 DEGREES BOTH
AFTERNOONS...LIKELY COOLEST ON SATURDAY WHEN RAIN COVERAGE WILL BE
GREATEST.
SUNDAY...AS THE UPPER LOW CENTER CONTINUES TO LIFT INTO EASTERN
CANADA...THE EAST COAST TROUGH WILL BECOME LESS AMPLIFIED TO THE
SOUTH. THIS WILL CAUSE THE COLD FRONT TO STALL AND BEGIN TO
DISSIPATE OVER OR NEAR THE FORECAST AREA EARLY NEXT WEEK. WEAK
HIGH PRESSURE WILL ATTEMPT TO BUILD FROM THE WEST AND INTRODUCE
DRIER AIR INTO THE SOUTHEAST STATES. EXPECT PRECIPITATION
POTENTIAL TO DECREASE AS A RESULT...AND HAVE LIMITED POPS INTO THE
SLIGHT CHANCE TO LOW CHANCE RANGE ACCORDINGLY. WILL INDICATE BEST
CONVECTIVE COVERAGE ACROSS SOUTHEAST GEORGIA ZONES CLOSEST TO
LINGERING MOISTURE ALONG THE SOUTHERN BOUNDARY OF THE DISSIPATING
FRONT.
TEMPERATURES ON SUNDAY WILL REBOUND INTO THE LOWER 90S AWAY FROM
THE LOCALLY COOLER COASTLINE DUE TO INCREASING INSOLATION AND A
SLIGHT INCREASE IN HEIGHTS ALOFT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A LESS AMPLIFIED UPPER LEVEL PATTERN IS EXPECTED MONDAY THROUGH
THE MIDDLE OF NEXT WEEK. THE SURFACE PATTERN WILL REMAIN RELATIVELY
WEAK AS WELL...WITH SUBTLE HIGH PRESSURE SETTLING OVER THE REGION
MONDAY AND TUESDAY. MEDIUM RANGE MODELS ARE IN SOME DISAGREEMENT
REGARDING THE TRACK OF SHORTWAVE ENERGY WITHIN THE BASE OF A WEAK
UPPER TROUGH THAT WILL TAKE SHAPE ALONG THE EAST COAST LATE
TUESDAY INTO THURSDAY. HAVE LIMITED PRECIPITATION CHANCES ON
MONDAY AND TUESDAY...LACKING NOTABLE DEEP MOISTURE AND UPPER LEVEL
SUPPORT. HAVE THEN INCREASED POPS SLIGHTLY FOR WEDNESDAY AND
THURSDAY TO ACCOUNT FOR THE FORMATION OF THE BROAD UPPER TROUGH
ALONG THE EAST COAST AND AN ASSOCIATED SURFACE WAVE OF LOW
PRESSURE. STILL EXPECT CONVECTION TO MAINTAIN A MORE SEASONAL
DIURNAL DEVELOPMENT PATTERN...WITH BEST COVERAGE DURING THE
FAVORED AFTERNOON/EVENING HOURS EACH DAY. HIGH TEMPERATURES WILL
GENERALLY RANGE IN THE LOWER 90S AWAY FROM THE LOCALLY COOLER
COASTLINE.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
PATCHY FOG IS POSSIBLE AROUND THE COASTAL CORRIDOR AROUND DAYBREAK
THIS MORNING AS HIGH CLOUDS WERE MAINLY THIN. OTHERWISE MAINLY VFR
CONDITIONS EXPECTED OUTSIDE OF IMPACTS FROM DIURNAL CONVECTION THIS
AFTERNOON AND EVENING. CONDITIONS APPEAR TO FAVOR KSAV FOR SLIGHTLY
HIGHER CHANCES AFTER 18Z AND WE CONTINUED THE PROB30 MENTIONS AND
LINGERED VCTS INTO THU EVENING. AT KCHS...TSTMS PROBABLY MORE HIT
OR MISS DURING PEAK HEATING TODAY. WILL NEED TO WATCH AFTER FOR
ADDITIONAL TSTMS LOOMING TO THE W AFTER SUNSET AT BOTH TERMINALS.
EXTENDED AVIATION OUTLOOK...
CONDITIONS WILL REMAIN UNSETTLED
THROUGH THE UPCOMING WEEKEND. BRIEF PERIODS OF MVFR OR LOWER
CONDITIONS WILL BE POSSIBLE WITH ANY SHOWERS AND
THUNDERSTORMS...MAINLY DURING THE AFTERNOON/EVENING HOURS.
&&
.MARINE...
NO SIGNIFICANT CHANGE TO SYNOPTIC PATTERN OR FORECAST CONDITIONS
TODAY WITH SW FLOW 10-15 KT EARLY AND LATE AND CLOSE TO 10 KT
AROUND MIDDAY. LOW LEVEL JET WILL INCREASE TONIGHT AND WE SHOULD
SEE WINDS INCREASE TO NEAR 15 KT WITH GUSTS TO 20 KT AT TIMES
AND SEAS BUILD FROM 2 FT TO 3-4 FT LATE.
FRIDAY THROUGH MONDAY...SOUTH TO SOUTHWEST FLOW WILL CONTINUE
ACROSS THE LOCAL WATERS UNDER THE INFLUENCE OF THE SUBTROPICAL
HIGH TO THE EAST. AS A COLD FRONT APPROACHES FROM THE NORTHWEST
EARLY THIS WEEKEND...THE LOW LEVEL FLOW WILL INCREASE WITH THE
TIGHTENING PRESSURE GRADIENT. WINDS COULD SURGE CLOSE TO MARGINAL
SMALL CRAFT ADVISORY LEVELS FRIDAY INTO EARLY SATURDAY...BUT STILL
EXPECT CONDITIONS TO REMAIN JUST BELOW CRITERIA AT THIS POINT.
SINCE THE FRONT IS EXPECTED TO DISSIPATE WITHOUT A CLEAR PASSAGE
ACROSS THE MARINE ZONES...WINDS WILL MAINTAIN A SOUTHERLY
COMPONENT INTO EARLY NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1238 AM EDT THU AUG 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 246 PM EDT WED AUG 8 2012
A FRONTAL SYSTEM IS EXPECTED TO DROP SOUTH INTO THE AREA TONIGHT. A
WAVE OF LOW PRESSURE WILL MOVE ACROSS NORTHERN INDIANA DURING THE
DAY ON THURSDAY. THIS WILL DRAG A COLD FRONT THROUGH THE AREA
THURSDAY AFTERNOON AND NIGHT. IN THE WAKE OF THIS FRONT...HIGH
PRESSURE WILL BUILD INTO THE REGION. ANOTHER WEAK FRONTAL SYSTEM MAY
AFFECT THE AREA LATE IN THE WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 920 PM EDT WED AUG 8 2012
FOR THE REMAINDER OF THE NIGHT...WITH QUASISTATIONARY BOUNDARY IN
THE AREA...AND WEAK UPPER LEVEL WAVES...INCLUDING REMNANT MCV
MOVING THROUGH SRN GREAT LAKES...EXPECT SCATTERED THUNDERSTORMS.
COVERAGE HAS BEEN SLOW TO EXPAND THUS FAR THIS EVENING...ALTHOUGH
THERE IS SOME HINT IN SREF PROBABILITIES...RAP...AND HRRR THAT
EXPANSION OF COVERAGE MAY OCCUR WITH A SLIGHT INCREASE IN MID
LEVEL FLOW LATE TONIGHT. CONSIDERING THIS...HAVE DEPICTED 40 TO 50
POPS WITH SCATTERED WORDING THROUGHOUT...AND POPS HIGHEST IN
VICINITY OF THE BOUNDARY. ISOLATED STRONG STORM CANNOT BE RULED
OUT...AND 5 PERCENT/SEE TEXT ON DAY ONE OUTLOOK PERFECTLY REASONABLE.
INCREASED CLOUD COVER AND AS A RESULT...IN CONCERT WITH LATEST
HOURLY NUMERICAL GUIDANCE AND OBSERVATIONAL TRENDS...BUMPED MIN
TEMPS UP SLIGHTLY IN SOME PORTIONS OF THE AREA. STILL MID 60S TO
AROUND 70...JUST SOME MINOR TWEAKS TO INDIVIDUAL NUMBERS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 246 PM EDT WED AUG 8 2012
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES WILL AFFECT THE
FORECAST AREA DURING THIS PERIOD. ONE WAVE...CURRENTLY OVER THE
UPPER MISSISSIPPI VALLEY...IS EXPECTED TO MOVE THROUGH THURSDAY
AFTERNOON AND EVENING. THIS WILL BE FOLLOWED BY AN UPPER LOW WHICH
WILL SETTLE INTO THE GREAT LAKES BY FRIDAY AND SATURDAY.
A SURFACE LOW ASSOCIATED WITH THE FIRST UPPER WAVE IS EXPECTED TO
MOVE ACROSS NORTHERN INDIANA THURSDAY AFTERNOON...WHICH WILL DRAG A
COLD FRONT THROUGH THE FORECAST AREA LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. THIS SETUP LOOKS TO PROVIDE THE BEST CHANCES FOR
PRECIPITATION DURING THIS PERIOD. DEEP LAYER SHEAR IS INITIALLY
RATHER WEAK...BUT GETS PROGRESSIVELY STRONGER TOWARDS THE LATE
AFTERNOON AND EARLY EVENING HOURS ON THURSDAY. MID LEVEL LAPSE RATES
ARE MARGINALLY FAVORABLE FOR SEVERE STORMS...SO THERE IS SOME
POTENTIAL FOR STORM ORGANIZATION AND ATTENDANT THREAT FOR MAINLY
WIND DAMAGE GIVEN THE INCREASING DEEP SHEAR. WILL CONTINUE TO
MENTION POPS FOR THURSDAY AND THURSDAY NIGHT...WITH THE HIGHEST POPS
AROUND FRONTAL PASSAGE...FROM MID AFTERNOON THURSDAY UNTIL ABOUT
MIDNIGHT THURSDAY NIGHT.
WILL KEEP A SMALL POP IN THE FORECAST FOR FRIDAY WITH THE UPPER LOW
IN THE AREA. APPEARS BY SATURDAY...THE UPPER LOW WILL HAVE DRIFTED
FAR ENOUGH OFF TO THE NORTHEAST TO KEEP THAT PERIOD DRY.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR THURSDAY
ARE PROBABLY ABOUT 3-6 DEGREES TOO LOW. THE HIGHS ON FRIDAY LOOK
BETTER...BUT MAY STILL BE A LITTLE COOL. GUIDANCE LOWS LOOK OK AT
THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 246 PM EDT WED AUG 8 2012
MODELS HAVE LOW RAIN CHANCES AT TIMES...BUT CONSIDERING RECENT
BIASES A TOTALLY DRY FORECAST BEST BET.
EUROPEAN MOS AND MEX TEMPS CLOSE THROUGH PERIOD. FOR MINS...CONSALL
MODEL WE INITIALIZED WITH IS ALSO CLOSE AND SEE NO REASON TO
CHANGE.
EVERYTHING AGREES GRADUAL WARMING THROUGH THE PERIOD. GIVEN RECENT
BIASES IN WARMING SITUATIONS WILL GO A FEW DEGREES ABOVE EVEN
RELATIVELY HOT CONSALL.
&&
.AVIATION /DISCUSSION FOR 090600Z TAF ISSUANCE/...
ISSUED AT 1238 AM EDT THU AUG 9 2012
WILL NEED TEMPO GROUPS AFTER 06Z AND PROB GROUPS THE REST OF THE
PERIOD AS AN UPPER TROUGH ACROSS THE MISSISSIPPI VALLEY PROGRESSES
EAST TOWARDS CENTRAL INDIANA...AND AN UPPER LOW MOVES TO NEAR LAKE
MICHIGAN AFTER 00Z TONIGHT. MEANWHILE...A FRONTAL BOUNDARY ALONG
WITH THUNDERSTORM OUTFLOW BOUNDARIES...DEEPER MOISTURE AND
INSTABILITY WILL ALSO SERVE TO FOCUS THUNDERSTORMS ACROSS CENTRAL
INDIANA THROUGH THE TAF PERIOD. CEILINGS SHOULD MOSTLY BE VFR AWAY
FROM THUNDERSTORMS UNTIL AFTER 00Z WHEN LOW LEVEL MOISTURE
INCREASES. COULD SEE SOME MVFR OR WORSE VISIBILITY AT TIMES IN
THUNDERSTORMS OR BRIEFLY IN FOG OVERNIGHT. MEANWHILE...WINDS SHOULD
BE LESS THAN 10 KNOTS EXCEPT IN STORMS OR NEAR OUTFLOW BOUNDARIES.
WIND DIRECTION WILL ALSO BE PROBLEMATIC DEPENDING ON WHERE THE
BOUNDARIES SET UP.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...NIELD
SHORT TERM...JAS
LONG TERM....JK
AVIATION...MK
AREA FORECAST DISCUSSION
NWS BILLINGS MT
325 AM MDT THU AUG 9 2012
.SHORT TERM...VALID FOR TDY AND FRI...
EARLY MORNING RAP MODEL DATA AND WATER VAPOR IMAGERY SHOWS THE
UPPER LEVEL RIDGE IS SLOWLY STARTING TO BREAK DOWN
ALREADY. EVEN THOUGH THE RIDGE WILL BECOME FLATTER
TODAY...CONDITIONS WILL STILL BE HOT AND DRY ACROSS THE REGION.
THERE IS A SLIGHT CHANCE FOR AN ISOLATED SHOWER OR
THUNDERSTORM...MAINLY OVER WESTERN ZONES...AS AN IMPULSE OF ENERGY
MAKES IT OVER THE AREA THIS AFTERNOON. THERE IS A LITTLE
INSTABILITY OVER MOUNTAINOUS REGIONS IN THE WESTERN ZONES...BUT
NOT SURE IF IT WILL BE REALIZED DUE TO STRONG CAP AT 850 AND 700
MB.
FOR FRIDAY...THE FOCUS TURNS TO THE POTENTIAL FOR WIDESPREAD
SHOWERS AND THUNDERSTORMS OVER MOST OF THE AREA. MODELS ARE
IN GOOD AGREEMENT IN PROGGING A SERIES OF VORTICITY POCKETS OVER
SOUTH CENTRAL MONTANA BY FRIDAY AFTERNOON. THE TIMING IS SLIGHTLY
DIFFERENT BETWEEN THE NAM AND GFS SOLUTIONS...WITH THE GFS
LINGERING A LITTLE BIT LONGER BEFORE EXITING THE CWA TO THE EAST.
500 TO 300 MB Q VECTOR MODEL FIELDS SHOW MAXIMUM CONVERGENCE JUST
NORTH OF THE CWA...WHICH WILL HELP TO DEVELOP A LEE SIDE TROUGH AT
THE SURFACE...AND WILL SERVE AS THE FOCUS FOR MOST OF THE
PRECIPITATION ACTIVITY. IN ADDITION...A WIND SPEED MAXIMA AT 850
WILL ATTEMPT TO SUPPLY MOISTURE TO THE AREA. THE MAIN MOISTURE
AXIS IS IN WESTERN SOUTH DAKOTA...BUT THE BREADTH OF THE LOW LEVEL
JET SHOULD BE WIDE ENOUGH TO HELP SUPPORT THUNDERSTORM GROWTH OVER
EASTERN ZONES BY FRIDAY NIGHT.
AS FAR AS INSTABILITY IS CONCERNED...LIFTED INDICES APPROACH -5 C
OVER SOUTHEAST MONTANA...WHICH COINCIDES WITH CAPE VALUES
APPROACHING 1000 J/KG AT MODEL SOUNDINGS FOR KBHK. AT CURRENT TIME
SHEAR PROFILES DO NOT APPEAR STRONG ENOUGH TO SUPPORT WIDESPREAD
SEVERE STORMS...BUT THAT MAY CHANGE AS THE SURFACE TROUGH SETS UP.
MAIN CONCERNS WOULD BE FOR LARGE HAIL AND STRONG WINDS. SINGER
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MODELS TRENDING A BIT SLOWER WITH DEPARTURE OF SECONDARY
SHORTWAVE ON SATURDAY...THUS LOOKS LIKE A BETTER CHANCE OF SHOWERS
AND THUNDERSTORMS ESPECIALLY IN OUR EAST ON THIS DAY. WITH
PRECIPITABLE WATERS ON THE ORDER OF 1.2 INCHES AND LOW LCL HEIGHTS
FROM KMLS-K4BQ EASTWARD THINK SOME HEAVY RAIN IS A POSSIBILITY.
THIS ENERGY WILL EXIT TO THE EAST BY SATURDAY EVENING. HAVE
TAPERED BACK EXPECTED HIGHS A BIT IN OUR EAST.
CHANCES OF PCPN NOT GREAT IN THE SUNDAY-TUESDAY TIME PERIOD AS
UPPER LEVEL RIDGE AND HIGH HEIGHTS WILL BE DOMINANT...BUT COULD BE
SOME MAINLY DIURNAL WEAK CONVECTION OVER OUR MTNS AND PERHAPS AT
TIMES IN OUR EAST WHERE LOW LEVEL BOUNDARY AND EAST WINDS WILL
LINGER. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH HIGHS MOSTLY
IN THE UPPER 80S TO MID 90S. TUESDAY MAY BE THE WARMEST DAY GIVEN
POTENTIAL FOR PREFRONTAL WARMING UNDER INCREASED SW FLOW ALOFT.
MODELS IN GOOD OVERALL AGREEMENT IN SHOWING A COOL DOWN BY
WEDNESDAY AND THURSDAY OF NEXT WEEK...THOUGH WITH DIFFERENCES IN
THE DETAILS AS SHARP UPPER TROF SLIDES OUT OF THE NORTHWEST. MODEL
CONSENSUS SUGGESTS COOL ADVECTION AND NORTH WINDS BEGINNING
WEDNESDAY AND A MUCH COOLER DAY BY THURSDAY...WITH INCREASED
CHANCES OF PRECIPITATION. WITH SOME CONFIDENCE HAVE RAISED POPS TO
ABOVE CLIMATOLOGY...AND EXPECT TEMPS TO FALL BELOW NORMAL BY
THURSDAY.
JKL
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL ACROSS THE REGION TODAY...WITH SOME
HIGH-BASED THUNDERSTORM ACTIVITY EXPECTED ESPECIALLY ALONG THE
MOUNTAINS AND FOOTHILLS THIS AFTERNOON AND EVENING. ERRATIC WIND
GUSTS ARE POSSIBLE NEAR ANY OF THESE STORMS. A WEAK COLD FRONT
WILL BRING A SHIFT TO NORTH OR NORTHEAST WINDS TODAY...EXCEPT IN
FAR EASTERN PARTS NEAR KMLS AND KBHK WHERE EASTERLY WINDS WILL
PERSIST. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 097 063/092 063/088 060/093 061/093 062/091 059/084
2/T 23/T 41/B 11/B 21/B 12/T 22/T
LVM 095 055/089 055/086 052/089 052/088 053/087 051/081
3/T 34/T 41/B 12/T 22/T 22/T 22/T
HDN 100 064/095 063/091 061/095 061/096 063/094 058/086
2/T 23/T 42/T 12/T 22/T 12/T 22/T
MLS 098 066/094 066/089 062/093 064/096 064/092 061/083
2/T 23/T 42/T 12/T 22/T 22/T 22/T
4BQ 097 065/093 064/089 061/093 062/094 065/093 058/083
2/T 23/T 42/T 12/T 22/T 22/T 22/T
BHK 091 063/090 063/086 060/088 061/090 064/089 060/080
1/B 23/T 52/T 22/T 22/T 22/T 22/T
SHR 096 060/091 060/087 056/091 058/094 059/090 055/082
2/T 23/T 42/T 12/T 22/T 11/B 22/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
139 AM EDT THU AUG 9 2012
.SYNOPSIS...
MID LEVEL WEAK SHORT WAVES MOVES FROM THE WEST OVERNIGHT. COLD
FRONT AFFECTS THE AREA THURSDAY AND FRIDAY. HIGH PRESSURE BUILDS
IN THIS WEEKEND WITH COOLER TEMPERATURES.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
ADJUSTED SKY AND POP GRIDS PER LATEST RADAR AND SATELLITE IMAGES.
ISOLATED CONVECTION CONTINUED TO FLARE ACROSS OUR SOUTHEASTERN
COUNTIES TONIGHT. RADAR SHOWING STRONG PULSES WITH HIGH HAIL CORE
ALOFT. COUPLE OF SEVERE STORM WARNINGS COULD BE ISSUED.
ADDITIONAL CONVECTION IS NOTED OVER OH...MOVING NORTHEAST AROUND 20
KNOTS. THIS CONVECTION COULD REACH PORTIONS OF SOUTHEAST OH
OVERNIGHT...CLOSER TO PERRY COUNTY OH. ADDITIONAL SHOWERS/STORMS
COULD DEVELOP ALONG OUTFLOW BOUNDARIES SOUTH OF THIS CLUSTER TO
AFFECT OTHER PORTIONS OF SOUTHEAST OH OVERNIGHT.
MODELS SHOW SMALL VORT MAXES APPROACHING SOUTHEAST OH
TONIGHT...OVER SFC DEWPOINTS IN THE MID TO UPPER 60S.
PREVIOUS DISCUSSION BELOW...
AT 02Z...HAVE SURFACE FRONT FROM NEAR PIT ON SW TO
CMH...CVG...THEN WEST ACROSS SOUTHERN INDIANA. 00Z RAP SHOWS MAIN
500 VORT MAX CROSSING NRN WV MTNS BY 03Z...BUT HAS A WEAKENING
VORT LINGERING IN NORTH CENTRAL WV THROUGH 06Z. MAY BE HELPING A
FEW LINGERING STORMS CROSSING THE OHIO RIVER AT 02Z.
WILL INCREASE AREAL COVERAGE OF THE FOG WHERE IT RAINS IN NRN
CENTRAL WV...BUT NOT CONFIDENT ON THE EXACT INTENSITY. WILL LIMIT
THE FOG IN SOUTHEAST OHIO SINCE BOUNDARY LAYER WINDS STAY UP...AND
CLOUDS WITH THE NEXT 500 VORT MAX SHOULD BE APPROACHING BY THE
PREDAWN HOURS.
ALSO...INCREASED POPS A BIT FASTER FOR OUR SOUTHEAST OHIO COUNTIES
DURING THE PREDAWN...WITH MORE SUPPORT ARRIVING...BEFORE LIFTING NE.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH FRIDAY NIGHT/...
MODELS IN REASONABLE AGREEMENT WITH THE MASS FIELDS AS VIGOROUS
UPPER LEVEL TROUGH AND ATTENDING COLD FRONT AFFECT OUR AREA FOR THE
END OF THE WORKWEEK.
IT IS SOMEWHAT OF A COMPLEX SYSTEM...AS THERE IS A LEAD UPPER TROUGH
OUT AHEAD OF THE MAIN UPPER TROUGH. THIS LEAD UPPER TROUGH WILL
OUTRUN THE FRONT AND MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS
THURSDAY NIGHT. WITHOUT A LOW LEVEL FOCUSING MECHANISM...WILL STAY
IN CHANCE CATEGORY. TEMPS WILL BE ON THE WARM SIDE OF GUIDANCE WITH
MOISTURE AND CLOUDS IN INCREASING SOUTHERLY FLOW.
THE COLD FRONT WILL WAIT FOR THE MAIN UPPER TROUGH SWINGING AROUND A
DEVELOPING CLOSED CENTER OVER THE GREAT LAKES FRIDAY...WHICH WILL
THEN ACCELERATE THE FRONT EASTWARD DURING FRIDAY. AGAIN...AS WITH
THE LAST SYSTEM...LOTS OF CLOUDS LIMITING HEATING AND TIMING OF THE
FRONT WILL LESSEN DESTABILIZATION FOR FRIDAY CONVECTION.
HOWEVER...GOOD DYNAMICS WILL STILL SUPPORT A BAND OF ORGANIZED
CONVECTION ALONG AND AHEAD OF THE FRONT ON FRIDAY. FOR TIMING...WILL
STILL GO WITH THE SLIGHTLY SLOWER NAM SOLUTION. WILL UP POPS TO
LIKELY IN WEST AROUND 12Z...MOVE ACROSS THE REMAINDER OF THE AREA
DURING THE DAY FRIDAY. BY FRIDAY EVENING...WHILE THE FRONT ITSELF
MAY LAG A BIT BEHIND THE UPPER TROUGH...THE WESTERN EDGE OF THE
DEEPER MOISTURE WILL MOVE INTO THE MOUNTAINS. THUS...WILL LOWER THE
POPS SIGNIFICANTLY BEHIND THE WESTERN EDGE QPF THE DEEPER
MOISTURE..BUT STILL KEEP SOME POPS WITH THE FRONT ITSELF. FRONT DOES
EXITS THE MOUNTAINS BEFORE 12Z SATURDAY...WITH A DRY SLOT WORKING IN
OVER MUCH OF THE AREA BY SATURDAY MORNING. MOST POPS BASICALLY END
WITH THE PASSAGE OF THE FRONT LATER FRIDAY NIGHT. ALSO MUCH COOLER
TEMPS WORK IN BY SATURDAY MORNING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SATURDAY WILL BE A TRANSITION CAY AS THE PROGRESSIVE UPPER LOW OVER
THE GREAT LAKES LIFTS OUT. WRAPAROUND MOISTURE WILL BRING LOTS OD
CLOUDS FOR MUCH OF SATURDAY...WITH LINGERING SHOWERS MAINLY IN THE
NORTH. MUCH COOLER WITH TEMPS STRUGGLING TO REACH 80. HIGH PRESSURE
TAKES CONTROL SUNDAY AND EARLY NEXT WEEK WITH DRY CONDITIONS AND
SLOWING REBOUNDING TEMPS...THANKS TO SUNSHINE. ONE NOTE...THE GFS
LOOKS TO BE THE OUTLIER ON A CLIPPER SYSTEM AND PRECIP ON TUESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
TRICKY FORECAST PINPOINTING WHICH AREAS WILL FOG TONIGHT. NORTHERN
PORTIONS RECEIVED PCPN YESTERDAY AFTERNOON AND EVENING.
HOWEVER...CLOUD COVER COULD BE THE PREVENTING FACTOR FOR DENSE
VALLEY FOG. THEREFORE...DELAYED THE ONSET OF DENSE IFR FOG AT PKB...CKB
AND EKN.
STRONG CONVECTION FIRING UP ACROSS CENTRAL OH...MOVING NORTHEAST.
RADAR IMAGES INDICATE AN OUTFLOW BOUNDARY FROM THIS COMPLEX
EXTENDING SOUTH...AND TRACKING TOWARDS SOUTHEAST OH. WITH
DEWPOINTS IN THE MID TO UPPER 60S...EXPECT THIS OUTFLOW BOUNDARY
TO INTERACT WITH THE MOISTURE IN PLACE AND TRIGGER ADDITIONAL
SHOWERS OR STORMS.
ENOUGH CLEARING SHOULD SUFFICE FOR DENSE VALLEY FOG AT CRW AND CKB AROUND
FROM 08-12Z TIME FRAME. DUE TO CLOUD COVER AROUND EKN...IFR IN 2SM
EXPECTED AFTER 10Z.
OTHER SITES MAY EXPERIENCE MVFR FOG CONDITIONS PER ABUNDANT
MOISTURE THROUGH 13Z.
BEST COVERAGE TO SCATTERED CONVECTION EXPECTED AFTER 18Z ACROSS
OHIO INTO NORTHERN WEST VIRGINIA COMPARED TO COUNTIES FURTHER TO
THE SOUTH.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LINGERING CLOUDS FROM EVENING CONVECTION COULD
DELAY OR DETER FOG FORMATION.
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 THU 08/09/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY M L L L L L L M H H H H
HTS CONSISTENCY M M M M M M M H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L L H H H H
PKB CONSISTENCY M M L L L L L M H H H H
CKB CONSISTENCY M M L L L L L M H H H H
AFTER 06Z FRIDAY...
IFR CONDITIONS POSSIBLE UNDER HEAVIEST SHOWERS/TSRA THURSDAY
AFTERNOON AND EVENING. IFR CONDITIONS ALSO POSSIBLE FRIDAY WITH
FRONT POST RAINFALL FOG.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...KTB
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1248 AM EDT THU AUG 9 2012
.SYNOPSIS...
MID LEVEL WEAK SHORT WAVES MOVES FROM THE WEST OVERNIGHT. COLD
FRONT AFFECTS THE AREA THURSDAY AND FRIDAY. HIGH PRESSURE BUILDS
IN THIS WEEKEND WITH COOLER TEMPERATURES.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
ADJUSTED SKY AND POP GRIDS PER LATEST RADAR AND SATELLITE IMAGES.
ISOLATED CONVECTION CONTINUED TO FLARE ACROSS OUR SOUTHEASTERN
COUNTIES TONIGHT. RADAR SHOWING STRONG PULSES WITH HIGH HAIL CORE
ALOFT. COUPLE OF SEVERE STORM WARNINGS COULD BE ISSUED.
ADDITIONAL CONVECTION IS NOTED OVER OH...MOVING NORTHEAST AROUND 20
KNOTS. THIS CONVECTION COULD REACH PORTIONS OF SOUTHEAST OH
OVERNIGHT...CLOSER TO PERRY COUNTY OH. ADDITIONAL SHOWERS/STORMS
COULD DEVELOP ALONG OUTFLOW BOUNDARIES SOUTH OF THIS CLUSTER TO
AFFECT OTHER PORTIONS OF SOUTHEAST OH OVERNIGHT.
MODELS SHOW SMALL VORT MAXES APPROACHING SOUTHEAST OH
TONIGHT...OVER SFC DEWPOINTS IN THE MID TO UPPER 60S.
PREVIOUS DISCUSSION BELOW...
AT 02Z...HAVE SURFACE FRONT FROM NEAR PIT ON SW TO
CMH...CVG...THEN WEST ACROSS SOUTHERN INDIANA. 00Z RAP SHOWS MAIN
500 VORT MAX CROSSING NRN WV MTNS BY 03Z...BUT HAS A WEAKENING
VORT LINGERING IN NORTH CENTRAL WV THROUGH 06Z. MAY BE HELPING A
FEW LINGERING STORMS CROSSING THE OHIO RIVER AT 02Z.
WILL INCREASE AREAL COVERAGE OF THE FOG WHERE IT RAINS IN NRN
CENTRAL WV...BUT NOT CONFIDENT ON THE EXACT INTENSITY. WILL LIMIT
THE FOG IN SOUTHEAST OHIO SINCE BOUNDARY LAYER WINDS STAY UP...AND
CLOUDS WITH THE NEXT 500 VORT MAX SHOULD BE APPROACHING BY THE
PREDAWN HOURS.
ALSO...INCREASED POPS A BIT FASTER FOR OUR SOUTHEAST OHIO COUNTIES
DURING THE PREDAWN...WITH MORE SUPPORT ARRIVING...BEFORE LIFTING NE.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH FRIDAY NIGHT/...
MODELS IN REASONABLE AGREEMENT WITH THE MASS FIELDS AS VIGOROUS
UPPER LEVEL TROUGH AND ATTENDING COLD FRONT AFFECT OUR AREA FOR THE
END OF THE WORKWEEK.
IT IS SOMEWHAT OF A COMPLEX SYSTEM...AS THERE IS A LEAD UPPER TROUGH
OUT AHEAD OF THE MAIN UPPER TROUGH. THIS LEAD UPPER TROUGH WILL
OUTRUN THE FRONT AND MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS
THURSDAY NIGHT. WITHOUT A LOW LEVEL FOCUSING MECHANISM...WILL STAY
IN CHANCE CATEGORY. TEMPS WILL BE ON THE WARM SIDE OF GUIDANCE WITH
MOISTURE AND CLOUDS IN INCREASING SOUTHERLY FLOW.
THE COLD FRONT WILL WAIT FOR THE MAIN UPPER TROUGH SWINGING AROUND A
DEVELOPING CLOSED CENTER OVER THE GREAT LAKES FRIDAY...WHICH WILL
THEN ACCELERATE THE FRONT EASTWARD DURING FRIDAY. AGAIN...AS WITH
THE LAST SYSTEM...LOTS OF CLOUDS LIMITING HEATING AND TIMING OF THE
FRONT WILL LESSEN DESTABILIZATION FOR FRIDAY CONVECTION.
HOWEVER...GOOD DYNAMICS WILL STILL SUPPORT A BAND OF ORGANIZED
CONVECTION ALONG AND AHEAD OF THE FRONT ON FRIDAY. FOR TIMING...WILL
STILL GO WITH THE SLIGHTLY SLOWER NAM SOLUTION. WILL UP POPS TO
LIKELY IN WEST AROUND 12Z...MOVE ACROSS THE REMAINDER OF THE AREA
DURING THE DAY FRIDAY. BY FRIDAY EVENING...WHILE THE FRONT ITSELF
MAY LAG A BIT BEHIND THE UPPER TROUGH...THE WESTERN EDGE OF THE
DEEPER MOISTURE WILL MOVE INTO THE MOUNTAINS. THUS...WILL LOWER THE
POPS SIGNIFICANTLY BEHIND THE WESTERN EDGE OPF THE DEEPER
MOISTURE..BUT STILL KEEP SOME POPS WITH THE FRONT ITSELF. FRONT DOES
EXITS THE MOUNTAINS BEFORE 12Z SATURDAY...WITH A DRY SLOT WORKING IN
OVER MUCH OF THE AREA BY SATURDAY MORNING. MOST POPS BASICALLY END
WITH THE PASSAGE OF THE FRONT LATER FRIDAY NIGHT. ALSO MUCH COOLER
TEMPS WORK IN BY SATURDAY MORNING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SATURDAY WILL BE A TRANSITION CAY AS THE PROGRESSIVE UPPER LOW OVER
THE GREAT LAKES LIFTS OUT. WRAPAROUND MOISTURE WILL BRING LOTS OD
CLOUDS FOR MUCH OF SATURDAY...WITH LINGERING SHOWERS MAINLY IN THE
NORTH. MUCH COOLER WITH TEMPS STRUGGLING TO REACH 80. HIGH PRESSURE
TAKES CONTROL SUNDAY AND EARLY NEXT WEEK WITH DRY CONDITIONS AND
SLOWING REBOUNDING TEMPS...THANKS TO SUNSHINE. ONE NOTE...THE GFS
LOOKS TO BE THE OUTLIER ON A CLIPPER SYSTEM AND PRECIP ON TUESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
CONTINUES TO BE A CHALLENGING AVIATION FORECAST OVERNIGHT IN REGARDS
TO DISSIPATING CONVECTION...LINGERING CLOUD DECK...AND FOG
FORMATION. MID LEVEL 500 MB VORT MAX AXIS PASSES EAST...OVER NRN WV
MOUNTAINS BY 03Z. CURRENTLY DO NOT HAVE HIGH ENOUGH POP FOR MENTION
CONVECTION AT ELKINS...SINCE TIMING IS AROUND 02Z/03Z...AND WAS
THINKING WEAKENING BY THEN. YET...CONVECTION SHOULD AFFECT PKB TO
CKB TO WESTON CORRIDOR 00Z TO 02Z. WITH LOCAL VSBY NEAR 3 MILES AND
CEILINGS 3 TO 4 THSD FT BKN.
INITIALLY WAS THINKING LESS FOG OVERNIGHT PKB TO CKB...BUT WITH THE
EVENING RAIN...WILL HOLD SOME THICKER FOG THERE 06Z TO 12Z.
YET...WITH BOUNDARY LAYER AND 925 MB FLOW...HAVE THE VISIBILITY MORE
VARIABLE ACROSS SOUTHEAST OHIO AND NORTHERN WEST VIRGINIA...COMPARED
TO THE EKN-CRW AND SOUTHERN WV COAL FIELDS FOR 06Z TO 12Z.
DID GO WITH LESS FOG TONIGHT AT HTS AND THE TRI STATE VICINITY THAN
WE PREVIOUS HAD...COUNTING ON NO SHOWERS AND THAT LOW LEVEL FLOW.
HAVE SOME 5 TO 8 THSD FT SCATTERED TO BROKEN CLOUDS FOR 12Z
THURSDAY...AND MAYBE A RAIN SHOWER IN SOUTHEAST OHIO. THEN CLOUDS
FORMING AT 3 TO 5 THSD FT SCATTERED TO BROKEN BY 15 TO 16Z.
BEST COVERAGE TO SCATTERED CONVECTION EXPECTED AFTER 18Z ACROSS
OHIO INTO NORTHERN WEST VIRGINIA COMPARED TO COUNTIES FURTHER TO THE
SOUTH.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LINGERING CLOUDS FROM EVENING CONVECTION COULD
DELAY OR DETER FOG FORMATION.
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 THU 08/09/12
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 M M H L L L L L L M
HTS CONSISTENCY H H M M H H H M H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H M L L L L L L L L L
PKB CONSISTENCY H M M M H L L L L L L M
CKB CONSISTENCY H H M M M L L L L L L M
AFTER 06Z FRIDAY...
IFR CONDITIONS POSSIBLE UNDER HEAVIEST SHOWERS/TSRA THURSDAY
AFTERNOON AND EVENING. IFR CONDITIONS ALSO POSSIBLE FRIDAY WITH
FRONT AS A RESULT OF CEILINGS AND SHOWERS/THUNDERSTORMS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...ARJ/KB
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS TULSA OK
1144 PM CDT WED AUG 8 2012
...UPDATE...
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
CONVECTION HAS WEAKENED CONSIDERABLY...WITH A FEW STORMS
POSSIBLE AT KFYV/KXNA THROUGH AROUND 08Z. COLD FRONT WILL
ENTER NORTHEAST OKLAHOMA THURSDAY MORNING AND PASS THROUGH
ALL TAF SITES BY 20-22Z. DROPPED MENTION OF VCTS AT KMLC
AND KFSM AS ANY ADDITIONAL DEVELOPMENT SHOULD STAY SOUTH
OF THESE SITES THURSDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 944 PM CDT WED AUG 8 2012/
..UPDATE...
DISCUSSION...
THE BULK OF EARLIER HEAVY CONVECTIVE ACTIVITY HAS MOVED SOUTH OUT
OF THE AREA. A COUPLE OF ISOLATED SMALL THUNDERSTORMS REMAIN IN
EASTERN OKLAHOMA... WITH SCATTERED STORMS CURRENTLY MOVING
SOUTHWARD TOWARD FAR NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS.
COOL AND MOIST OUTFLOW HAS MOVED ACROSS THE ENTIRE FORECAST AREA
WITH THE EXCEPTION OF FAR WESTERN OSAGE AND PAWNEE COUNTIES.
TEMPERATURES IN SOME RAIN-COOLED AREAS BRIEFLY DIPPED BELOW
FORECAST OVERNIGHT LOWS BEFORE WARMING AGAIN. HAVE NOT CHANGED
FORECAST LOWS SINCE DEWPOINTS HAVE NOW RISEN ENOUGH TO PUT A
BOTTOM UNDER TEMPS. HOWEVER... HAVE UPDATED DEWPOINTS IN THE GRIDS
AND ASSOCIATED CALCULATED GRID ELEMENTS. POPS FOR THE REMAINDER OF
THE NIGHT LOOK GOOD... WITH HIGHEST CHANCES REMAINING TOWARD THE
EAST. UPDATED PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 625 PM CDT WED AUG 8 2012/
.UPDATE...
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SCATTERED STRONG TO SEVERE STORMS ALONG WITH MULTIPLE
OUTFLOW BOUNDARIES WILL CONTINUE TO RESULT IN ERRATIC
WIND DIRECTIONS AND SPEEDS FOR THE NEXT SEVERAL HOURS.
THUNDERSTORMS NEAR THE KMLC TAF SITE WILL GRADUALLY
DIMINISH AFTER 02Z...WITH ADDITIONAL STORMS POTENTIALLY
IMPACTING THE KFYV/KXNA SITES FROM THE NORTH BY 01-02Z.
EXPECT PERIODIC MVFR/IFR CONDITIONS IN AND NEAR STORMS.
MOST OF THE ACTIVITY SHOULD WEAKEN AFTER 06Z. A COLD
FRONT WILL MOVE THROUGH THE REGION THURSDAY MORNING
AND COULD RESULT IN A FEW LATE AFTERNOON STORMS FOR
KMLC/KFSM.
PREV DISCUSSION... /ISSUED 343 PM CDT WED AUG 8 2012/
DISCUSSION...
ONGOING CONVECTION WILL MAINTAIN A RISK OF DAMAGING DOWNBURST
WINDS ACROSS SE OK AND WESTERN AR INTO SUNSET...WITH ATTENTION
THEN TURNING TO EXPANDING CONVECTION ACROSS THE CENTRAL PLAINS.
THIS CONVECTION WILL BE FORCED BY A RESPECTABLE MID LEVEL WAVE FOR
EARLY AUGUST...AND LIKELY DEVELOP SOUTH AND EASTWARD AFTER SUNSET.
GIVEN THE DEEPLY MIXED AND NOT-YET OVERTURNED BOUNDARY LAYER IN
PLACE ACROSS NE OK...THE CONVECTION WILL HAVE A GOOD CHANCE OF
DEVELOPING INTO THE REGION. THE SOUTHWARD EXTENT SHOULD BE LIMITED
BY THE ONGOING CONVECTION AND ITS EFFECTS ON STABILIZING THE
BOUNDARY LAYER. THIS SCENARIO IS LARGELY SUPPORTED BY THE 18Z NAM
AND HRRR OUTPUT.
THE COLD FRONT ASSOCIATED WITH THE PASSING WAVE WILL MOVE INTO NE
OK BY SUNRISE THURSDAY...AND THROUGH MUCH OF THE FORECAST AREA BY
SUNSET THURSDAY. STORM CHANCES WILL RESIDE ALONG AND SOUTH OF THE
BOUNDARY PRIMARILY DURING THE AFTERNOON HOURS ON THURSDAY.
NOTICEABLY DRIER AND COOLER AIR WILL FOLLOW THE FRONT AND BRING
TEMPS NEAR NORMAL FRIDAY AND SATURDAY. RAINFALL FOOTPRINTS...OR
LACK THEREOF...MAY LARGELY AFFECT THE DEGREE OF COOLING GIVEN THE
VERY WARM GROUND TEMPS AND LACK OF CLOUD COVER BEHIND THE FRONT.
UPPER RIDGING WILL ATTEMPT TO EXPAND BACK EASTWARD OVER THE
WEEKEND...THOUGH IT LOOKS TO BE SUPPRESSED FURTHER SOUTH AND NOT
HAVE AS STRONG AS INFLUENCE AS RECENTLY. SOUTHERN PERIPHERY OF A
PASSING WAVE MAY SUPPORT PRECIP LATE SUNDAY INTO
MONDAY...OTHERWISE NO SIGNIFICANT PRECIP CHANCES ARE NOTED UNTIL
POSSIBLY JUST BEYOND THIS FORECAST TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 75 100 69 92 / 30 10 0 0
FSM 74 104 70 93 / 30 10 10 10
MLC 71 103 69 94 / 30 0 10 0
BVO 69 99 64 92 / 30 10 0 0
FYV 67 97 64 87 / 40 10 10 0
BYV 70 95 66 85 / 50 10 10 0
MKO 73 102 69 93 / 40 10 10 0
MIO 71 97 68 88 / 40 10 0 0
F10 73 102 70 93 / 30 0 0 0
HHW 70 103 73 95 / 30 20 10 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...18
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1110 PM CDT WED AUG 8 2012
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW...
&&
.AVIATION...
MOST OF THE CONVECTION ACROSS THE AREA HAS DISSIPATED THIS
EVENING...WITH A FEW LIGHT SHOWERS ACROSS THE NORTHWEST HILL
COUNTRY. EXPECT WINDS TO REMAIN LIGHT AND VARIABLE WITH VFR
CONDITIONS PREVAILING THROUGH THE PERIOD. AN ISOLATED SHOWER OR
THUNDERSTORMS IS POSSIBLE THURSDAY AFTERNOON AT KJCT AND
KSOA...BUT CONFIDENCE IS TOO LOW TO INCLUDE IN THE CURRENT TAF
PACKAGE.
&&
.PREV DISCUSSION... /ISSUED 601 PM CDT WED AUG 8 2012/
DISCUSSION...
SEE AVIATION DISCUSSION BELOW...
AVIATION...
A BROKEN LINE OF SHOWERS AND THUNDERSTORMS WAS LOCATED ALONG A
LINE FROM NEAR OZONA...TO FORT MCKAVETT...TO BRADY. EXPECT THIS
ACTIVITY TO CONTINUE TO MOVE SOUTH THROUGH THE NEXT COUPLE OF HOURS. AN
ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE AT MAINLY
KBBD...KJCT AND KSOA...WITH MOST OF THE ACTIVITY WINDING DOWN BY
02Z. BRIEF HEAVY RAINFALL AND GUSTY WINDS TO NEAR 40 MPH WILL BE
POSSIBLE WITH THESE STORMS. TONIGHT THROUGH LATE THURSDAY
MORNING...EXPECT VFR CONDITIONS AND LIGHT AND VARIABLE WINDS.
PREV DISCUSSION... /ISSUED 359 PM CDT WED AUG 8 2012/
SHORT TERM...
SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE HEARTLAND
AND CONCHO VALLEY THIS AFTERNOON. THIS ACTIVITY IS DEVELOPING
IN ASSOCIATION WITH LIFT FROM A WEAK SHORT WAVE THAT IS
OVERSPREADING THE AREA FROM THE NORTH. LATEST HRRR SEEMS TO BE
DOING A DECENT JOB SO FAR AND INDICATES ADDITIONAL DEVELOPMENT
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA THROUGH EARLY EVENING.
WILL MAINTAIN 30 POPS SOUTH AND SLIGHT CHANCE POPS NORTH ACROSS
THE BIG COUNTRY THROUGH THE EVENING HOURS. MAY STILL SEE SOME
LINGERING ACTIVITY ALONG THE I-10 CORRIDOR THROUGH LATE EVENING
BUT MOST OF THE CONVECTION SHOULD DISSIPATE AFTER SUNEST. THE MAIN
THREAT FROM THUNDERSTORMS WILL BE LOCALLY HEAVY RAINFALL...GUSTY
WINDS AND DANGEROUS CLOUD TO GROUND LIGHTNING.
DRIER AIR WILL FILTER INTO THE AREA FROM THE NORTH LATER TONIGHT AND
THURSDAY. THIS WILL RESULT IN DRY AND HOT CONDITIONS ACROSS THE AREA
WITH AFTERNOON HIGHS AROUND THE CENTURY MARK. CANNOT RULE OUT AN
ISOLATED STORM OR TWO ACROSS SOUTHEAST SECTIONS THURSDAY AFTERNOON
SO KEPT ISOLATED MENTION OVER THIS AREA.
LONG TERM...
AS AN UPPER TROUGH AND LOW DROP SOUTHEAST ACROSS THE LOWER
GREAT LAKES REGION...TRAILING PORTION OF ASSOCIATED COLD
FRONT WILL MOVE SOUTH INTO THE BIG COUNTRY THURSDAY NIGHT...
AND ACROSS THE REST OF WEST CENTRAL TEXAS ON FRIDAY. THIS
PORTION OF THE FRONT WILL BE WEAK HOWEVER...WITH THE MAIN
ADVECTION OF COOLER AIR EXPECTED TO BE TO THE NORTHEAST OF
OUR AREA. WITH WEAK SURFACE CONVERGENCE AND A DRIER AIRMASS
PROGGED...RAIN CHANCES LOOK LOOK TOO SMALL INCLUDE IN OUR AREA
WITH THE ARRIVAL/PASSAGE OF THIS FRONT. TEMPERATURES WILL BE
SLIGHTLY COOLER ACROSS THE BIG COUNTRY...WHERE HIGHS FRIDAY
ARE EXPECTED TO BE IN THE MID/UPPER 90S.
THE UPPER HIGH WILL BE CENTERED OVER NEW MEXICO DURING THE
WEEKEND. GIVEN ITS PROXIMITY...HOT AND DRY CONDITIONS CAN BE
EXPECTED FOR WEST CENTRAL TEXAS. THE WARMEST READINGS ARE
EXPECTED SUNDAY...WHEN HIGHS SHOULD RANGE FROM 100-105 DEGREES
AREAWIDE. LITTLE CHANGE IS INDICATED WITH THIS PATTERN THROUGH AT
LEAST EARLY NEXT WEEK. THE 12Z GFS AND ECMWF SHOW A WEAKENING WITH
THIS HIGH BY NEXT TUESDAY OR WEDNESDAY...WITH THE GFS BRINGING A
DISTURBANCE NORTH-NORTHEAST FROM THE LOWER RIO GRANDE VALLEY INTO
CENTRAL AND EASTERN TEXAS. GIVEN THAT THIS IS LATE DAY 6 AND DAY
7...LEANING AT THIS TIME TOWARD PERSISTENCE WITH THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 74 101 72 97 70 / 20 10 10 5 5
SAN ANGELO 74 101 73 101 70 / 20 20 10 10 5
JUNCTION 73 97 72 101 70 / 20 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DANIELS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
241 AM CDT THU AUG 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY
241 AM CDT THU AUG 9 2012
MAIN CONCERNS INCLUDE RAIN CHANCES TODAY INTO THIS EVENING/FOG FRIDAY
NIGHT/TEMPERATURES THROUGH THE PERIOD.
LATEST WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWING A MID-LEVEL
SHORTWAVE TROUGH MOVING SOUTHEAST ACROSS SOUTHERN WI/EASTERN IA.
ANOTHER MORE VIGOROUS SHORTWAVE WAS MOVING SOUTH THROUGH WESTERN
ONTARIO/ARROWHEAD REGION OF MN. SOUTHERN SHORTWAVE TROUGH
DEFORMATION AREA WAS PRODUCING SOME 700MB FRONTOGENETIC FORCING AND
RESULTING IN SCATTERED -SHRA ACTIVITY MAINLY EAST OF THE MISSISSIPPI
RIVER. RAP SHOWS THIS FRONTOGENESIS WEAKENING OVER THE NEXT FEW
HOURS...AND RADAR MOSAIC ALREADY SHOWING DISSIPATION OF THE SHRA
ACTIVITY. MEANWHILE...THE TROUGH DROPPING SOUTH THROUGH
ONTARIO/NORTHERN MN WAS PRODUCING A MORE ORGANIZED BAND OF
SHRA/ISOLD THUNDER IN GOOD 700-300MB PV-ADVECTION PER THE RAP.
OTHERWISE...SKIES ACROSS THE AREA WERE MOSTLY CLOUDY WITH
TEMPERATURES IN THE 60S.
LATEST NCEP MODELS/SREF REMAIN IN GOOD AGREEMENT THROUGH THE SHORT
TERM PERIOD.
FOR TODAY...WILL BE WATCHING THE WAVE OVER ONTARIO/NORTHERN MN DROP
SOUTHEAST ACROSS THE AREA. INCREASING PV-ADVECTION/STEEPENING LAPSE
RATES ACROSS THE AREA WILL LEAD TO MORE SHOWER/THUNDER DEVELOPMENT.
BEST FORCING APPEARS TO BE EAST OF THE MISSISSIPPI...SO TRENDED POPS
HIGHER THERE. IN ADDITION...THE NAM INDICATING 0-3KM MUCAPE
INCREASING INTO THE 1000-1500J/KG RANGE BY NOON WITH BULK SHEAR IN THE
15 TO 30KT RANGE FOR PERHAPS SOME LINEAR ORGANIZATION OF THE
CONVECTION. WITH THIS IN MIND...ALONG WITH COLDER AIR ALOFT AND
LOWERING WET BULB ZERO HEIGHTS...WILL HAVE TO WATCH FOR ISOLATED
SEVERE THREAT TODAY WITH HAIL AND WIND BEING THE MAIN THREATS.
OTHERWISE...TEMPERATURES WILL BE A BIT COOLER WITH THE
TROUGH/SCATTERED CONVECTION. ANTICIPATING HIGHS TODAY RANGING FROM
THE UPPER 60S ACROSS NORTH CENTRAL WI...TO THE LOWER/MID 70S
ELSEWHERE.
LOOK FOR THE TROUGH TO DEEPEN/FORM A CLOSED LOW AS IT MOVES
SOUTHEAST OF THE AREA TONIGHT TOWARD IN/MI BORDER BY FRI 12Z. AT THE
SURFACE...HIGH PRESSURE WILL BE BUILDING INTO THE AREA WITH
DRYING/NORTHERLY FLOW. THIS IS EXPECTED TO DRY UP/PUSH ANY LINGERING
SHRA ACTIVITY SOUTHEAST OF THE AREA BY MIDNIGHT...WITH CLEARING
SKIES FROM NORTHWEST TO SOUTHEAST. LOOK FOR LOWS IN THE LOWER/MID
50S WITH POCKETS OF MID/UPPER 40S IN THE CRANBERRY BOG AREAS OF
CENTRAL WI.
ON FRIDAY...CLOSED MID-LEVEL AND DEEP SURFACE LOW WILL HANG UP OVER
SOUTHERN LOWER MI AS HIGH PRESSURE CONTINUES TO BUILD INTO OUR AREA.
DECENT DRYING NORTHERLY FLOW WILL RESULT ACROSS THE AREA. MAY SEE
SOME CUMULUS BUILD UP ACROSS THE EASTERN PORTION OF THE AREA DUE TO
CLOSER PROXIMITY OF COLDER/CYCLONIC FLOW ALOFT. TRENDED DEW POINTS
LOWER DUE TO ANTICIPATED DEEPER MIXING TO 825MB PER THE NAM BUFKIT
SOUNDING. HIGH TEMPERATURES WILL CONTINUE TO BE A BIT ON THE COOLER
THAN NORMAL SIDE IN THE 70S.
HIGH PRESSURE WILL SETTLE OVERHEAD FRIDAY NIGHT WITH THE RIDGE AXIS
OVER AT LEAST THE WESTERN HALF OF THE FORECAST AREA. LIGHT
WINDS/CLEAR SKIES AND WATER TEMPERATURES SITTING IN THE UPPER 70S
WILL LIKELY LEAD TO SOME RIVER VALLEY FOG TOWARD MORNING.
OTHERWISE...OVERNIGHT LOWS WILL BE QUITE COOL IN THE 40S. HIGH
PRESSURE CONTINUES TO BE IN CONTROL ACROSS THE AREA THROUGH SATURDAY
FOR DRY CONDITION WITH HIGHS IN THE MID/UPPER 70S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
241 AM CDT THU AUG 9 2012
LATEST GFS/ECMWF I FAIRLY DECENT AGREEMENT THROUGH THE EXTENDED
FORECAST PERIOD. BOTH SHOW A WEAK MID-LEVEL TROUGH MOVING EAST OUT
OF THE DAKOTAS/CENTRAL PLAINS TOWARD THE AREA SATURDAY NIGHT THROUGH
SUNDAY NIGHT FOR A SMALL CHANCE OF SHOWER/THUNDERSTORMS. A MORE
SIGNIFICANT LOW PRESSURE SYSTEM IS SLATED TO MOVE EAST OUT OF THE
PACIFIC NORTHWEST INTO THE REGION BY WEDNESDAY. WARM AIR ADVECTION
IN ADVANCE OF THIS SYSTEM WILL GIVE THE AREA INCREASING
SHOWER/THUNDERSTORM CHANCES FROM TUESDAY INTO WEDNESDAY.
OTHERWISE...LOOK FOR TEMPERATURES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL IN THE EXTENDED WITH HIGHS WARMING FROM THE 70S ON SUNDAY TO
WELL INTO THE 80S TUESDAY AND WEDNESDAY.
&&
.AVIATION...THROUGH 06Z FRIDAY
1156 PM CDT WED AUG 8 2012
COMPLICATED WEATHER SYSTEM TO AFFECT THE TAFS THROUGH THE PERIOD.
MOISTURE CONVERGENCE IN THE LOW-LEVELS IS LEADING TO SHOWERS JUST
NORTH OF THE TAF SITES OVERNIGHT. WITHIN THIS SHOWER BAND CIGS ARE
MVFR AND AS SUNRISE APPROACHES...IFR CAN BE EXPECTED. THIS AREA OF
CLOUD WILL SHIFT INTO THE TAFS TO CAUSE THE MVFR/IFR OVERNIGHT. AS
THE DAYTIME CONTINUES...CIGS SHOULD IMPROVE.
A VIGOROUS WEATHER SYSTEM WILL SHIFT THROUGH WI DURING THE DAY BUT
KLSE IS EXPECTED TO BE FAR ENOUGH WEST TO NOT SEE TSRA CHANCES.
HOWEVER...THIS MAY NEED TO BE ADDED TO FUTURE FORECASTS SHOULD
TSRA THREAT INCREASE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
241 AM CDT THU AUG 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS ALBANY NY
1020 AM EDT THU AUG 9 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL SLOWLY TRACK SOUTHWARD AND STALL
OVER UPSTATE NEW YORK TODAY...ALLOWING FOR SHOWERS AND THUNDERSTORMS
DURING THE AFTERNOON AND EVENING HOURS. A FEW OF THESE STORMS MAY
BE STRONG. MEANWHILE...LOW PRESSURE WILL ORGANIZE OVER THE MIDWEST
TONIGHT...AND MOVE INTO THE EASTERN GREAT LAKES BY SATURDAY. ITS
ASSOCIATED COLD FRONT WILL ADVANCE TOWARD THE LOCAL REGION FRIDAY
AND CROSS THE REGION SATURDAY...ALLOWING FOR ADDITIONAL SHOWERS AND
THUNDERSTORMS...SOME OF WHICH WILL CONTAIN HEAVY RAINFALL.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM EDT...THE POTENTIAL IS INCREASING FOR A FEW SEVERE
THUNDERSTORMS THIS AFTERNOON AND INTO THE EVENING HOURS.
FOG/STRATUS HAS CLEARED OUT OF THE MAJORITY OF THE AREA...AND
DEWPOINTS REMAIN VERY HIGH...WITH TDS CURRENTLY 65-70 DEGREES F. A
STALLED OUT STATIONARY BOUNDARY REMAINS JUST NORTHWEST OF THE
REGION. ALTHOUGH DEEP LAYER SHEAR IS LIMITED FOR SOUTHEASTERN
AREAS...IT SHOULD INCREASE TO 25-40 KTS FOR AREAS NORTH AND WEST
OF THE CAPITAL REGION BY LATE THIS AFTN/THIS EVENING /ACCORDING TO
THE 06Z GFS/. FORECASTED CAPE FOR TODAY OFF THE 12Z KALY SOUNDING
IS ABOUT 2300-2800 J/KG ACROSS THE REGION...AND MID LEVEL LAPSE
RATES ARE RESPECTABLE /BOTH THE 06Z GFS AND NAM SHOW 850-500 MB
LAPSE RATES OF AROUND 6 C/KM/. AS A RESULT...SPC HAS NUDGED MOST
OF OUR AREA BACK IN THE SLIGHT RISK. WE WILL NEED TO MONITOR RADAR
TRENDS BY THE EARLY AFTN HOURS...AS BOTH THE LOCAL HIRES WRF AND
3KM HRRR SHOW CONVECTION DEVELOPING DURING THE EARLY AFTN
HOURS...ALTHOUGH THE HRRR SHOWS THE ACTIVITY BECOMING MORE
ORGANIZED THAN THE WRF.
TONIGHT...THE FORECAST WRF NMM AND ARW CORES SUGGEST A LULL IN THE
ACTIVITY AS THE MAIN UPPER LOW CURRENTLY TRACKING ACROSS THE
ARROWHEAD OF MINNESOTA BEGINS TO CARVE OUT AN ANOMALOUS LOWERING
HEIGHTS INTO THE OHIO VALLEY AND CENTRAL GREAT LAKES REGION.
HOWEVER...THE GLOBAL MODELS SUGGEST THE INCREASE IN
THETA-E/MOISTURE TRANSPORT VECTOR MAGNITUDES WILL CONTINUE WITH
SHOWER DEVELOPMENT OVERNIGHT. MOS GUIDANCE DOES LOWER POPS
OVERNIGHT BUT NOT TOO LOW TO DROP MENTION OF PRECIP FROM THE
FORECAST/GRIDS. THEREFORE...WE WILL CONTINUE WITH THE 30-40% POPS
OVERNIGHT FOR THE ENTIRE REGION WITH SHOWERS AND THE CHANCE FOR
THUNDERSTORMS. AS LOW LEVEL MOISTURE INCREASES FURTHER AND SURFACE
WINDS EXPECTED TO DECOUPLE...AREAS OF FOG ARE EXPECTED AND WILL
INCLUDE IN THE GRIDS/FORECAST. OVERNIGHT LOWS WILL BE WARM AND
MUGGY WITH VALUES MAINLY INTO THE L-U 60S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AN ACTIVE PERIOD OF WEATHER WITH THE POTENTIAL FOR SEVERE
WEATHER AND HEAVY RAINFALL...
NCEP MODEL SUITE AND INTERNATIONAL GUIDANCE THIS MORNING CONTINUE
TO ADVERTISE AN UNSEASONABLY LOWER HEIGHT ANOMALIES OVER THE MID
WEST AS UPPER LOW EVOLVES. THIS LEAVES OUR REGION WITHIN A
SOUTHERLY INCREASE OF WARM AND MOIST CONVEYOR BELT AS PWATS CLIMB
TOWARD 2 INCHES THROUGH THE SHORT TERM. SEVERE POTENTIAL ON FRIDAY
COULD BE RATHER INTERESTING AS IT WILL BE HIGHLY DEPENDENT ON
ACCUMULATED INSOLATION. AS THIS UPSTREAM SYSTEM DEEPENS...OUR LOW
LEVEL FLOW IS FORECAST TO BACK SLIGHTLY WHICH COULD BE MESOSCALE
ENHANCED WITHIN THE HUDSON VALLEY REGION. MUCAPES ON FRIDAY COULD
EXCEED 2K J/KG WITH ENOUGH INSOLATION FOR MORE ROBUST CONVECTION. IN
COLLABORATION WITH SPC THIS MORNING...SLIGHT RISK WAS ADJUSTED
NORTHWARD TO ENCOMPASS THE SOUTHERN 2/3RDS OF THE CWFA. PER THERE
EXCELLENT DISC...
SOMEWHAT STRONGER DEEP AND LOW LEVEL SHEAR MAY DEVELOP FROM NRN
MID ATLANTIC INTO ERN PORTION OF THE OH VALLEY AND NERN STATES IN
ASSOCIATION WITH A MID LEVEL JET ROTATING THROUGH SERN PERIPHERY
OF THE UPPER LOW. IF SUFFICIENT INSTABILITY DEVELOPS...STORMS MAY
BECOME A BIT MORE ORGANIZED IN THIS REGION WITH POTENTIAL FOR
EMBEDDED MESOCYCLONES AND BOWING SEGMENTS. DAMAGING WIND WILL BE
THE MAIN THREAT...BUT A CONDITIONAL THREAT WILL EXIST FOR A COUPLE
OF TORNADOES.
FURTHERMORE...AS THOSE PWATS INCREASE...SO DOES THE POTENTIAL FOR
HEAVY RAINFALL FRIDAY INTO FRIDAY NIGHT. PER THE CSTAR III
RESEARCH...SEVERAL PIECES POINT TOWARD HEAVY RAINFALL BUT NOT ALL
OF THE PIECES APPEAR TO LINE UP TOO WELL. WHILE THE POTENTIAL FOR
SOME TRAINING ECHOES IS APPARENT...FLASH FLOOD GUIDANCE REMAINS
RATHER HIGH WITH COUNTY VALUES RANGING FROM 2-4 INCHES ALONG WITH
OUR RECENT DRY WEATHER TRENDS. SO HEADLINES AT THE PRESENT TIME AS
WE WILL CLOSELY MONITOR TRENDS AND CONTINUE TO MAKE FORECAST
ADJUSTMENTS. WE WILL CONTINUE TO HIGHLIGHT THESE HAZARDS IN THE HWO
THIS MORNING.
GUIDANCE IS SOMEWHAT IN TIMING DISAGREEMENTS WITH THE DEPARTURE
OF THE FRONTAL BOUNDARY ON SATURDAY. AS SUGGESTED BY THE LATEST
ENSEMBLES...WE WILL FAVOR MORE TOWARD THE ECMWF TIMING WHICH
KEEPS POPS INTO THE CHC-SCT CATEGORY ALONG AND EAST OF THE HUDSON
RIVER WITH DECREASED POPS FURTHER WEST AS THAT DRY SLOT
APPROACHES. AS SOME PARTIAL SUNSHINE IS EXPECTED...ALONG WITH A
MOIST GROUND...HIGHS SATURDAY AFTERNOON CLIMB INTO THE LOWER 80S
FOR VALLEY LOCATIONS AND 70S ELSEWHERE PER 850MB TEMPS INTO THE
LOWER-MID TEENS CELSIUS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HAVE POPULATED THIS PORTION OF GRIDDED DATABASE WITH A 50/50
BLEND OF 18Z/08 HPC GUIDANCE AND 00Z/09 GMOS.
SAT NT-SUN NT...MAIN OCCLUDED/COLD FRONT SHOULD MOVE E OF THE REGION
EARLY SAT NT...AS MID LEVEL DRY SLOT PUNCHES NORTHEAST ACROSS AREA.
THIS SHOULD ALLOW SHOWERS TO TAPER OFF...ALTHOUGH CAN NOT COMPLETELY
RULE OUT ADDITIONAL LIGHTER SHOWERS...OR AREAS OF DRIZZLE...ESP
ACROSS THE SOUTHERN ADIRONDACKS...AND HIGHER ELEVATIONS ACROSS
WESTERN NEW ENGLAND. THEN...AS THE MID/UPPER LEVEL COLD POOL MOVE
ACROSS DURING SUNDAY/SUNDAY EVENING...DIURNALLY DRIVEN SHOWERS
SHOULD DEVELOP...ESP ACROSS HIGHER ELEVATIONS. WILL INDICATE SLIGHT
CHC TO LOW CHC POPS FOR SUNDAY TO ACCOUNT FOR THIS. EXPECT TEMPS TO
BE NEAR OR A BIT BELOW SEASONAL LEVELS...GENERALLY 75-80 WITHIN
VALLEY REGIONS...AND 60S TO LOWER 70S ACROSS HIGHER ELEVATIONS.
OVERNIGHT MINS SHOULD FALL INTO HE LOWER 60S IN VALLEY AREAS...AND
50S ELSEWHERE FOR SUNDAY MORNING...THEN A FEW DEGREES
COOLER...MAINLY 50S...FOR MON AM.
MONDAY-MONDAY NIGHT...WEAK RIDGE OF HIGH PRESSURE SHOULD SLIDE
ACROSS THE REGION...WITH GENERALLY FAIR CONDITIONS. TEMPS SHOULD
REACH 80-85 IN VALLEYS..AND 75-80 ACROSS HIGHER ELEVATIONS...WITH
OVERNIGHT MINS FALLING INTO THE LOWER 60S ACROSS THE HUDSON RIVER
VALLEY...AND LOWER/MID 50S ACROSS THE SOUTHERN ADIRONDACKS.
TUE-WED...MOST LONG RANGE MODELS INDICATE ANOTHER POTENTIAL UPPER
LEVEL LOW DIGGING SOUTHWARD FROM EASTERN CANADA INTO THE NORTHEAST
STATES. DEPENDING ON THE EXPECT PATH AND EVOLUTION OF THIS
FEATURE...SHOWERS AND POSSIBLE THUNDERSTORMS MAY OCCUR DURING THIS
PERIOD...ESP TUE NT/WED. TEMPS SHOULD REACH 80-85 IN VALLEYS...AND
75-80 ACROSS HIGHER ELEVATIONS...WITH OVERNIGHT MINS FALLING INTO
THE LOWER/MID 60S IN VALLEYS...AND 55-60 ACROSS HIGHER ELEVATIONS.
500HPA CUTOFF LIFTS NNE INTO QB TAKING CLOUDS AND THE THREAT OF
-SHRA WITH IT SUNDAY ON ECMWF. AT SFC W FLOW BCMS EST ACROSS THE
RGN..AND BY EVENING SFC HIGH BUILDS OVER THE MID ATLC. GFS/GEM
HOLDING SOME CLOUDS AND MINIMAL QPF OVER NW PERIPHERY OF FCA...BUT
OTRW A FAIR DAY. CONDS REMAIN DRY MONDAY AS SFC HIGH HOLDS OVER MID
ATLC AND 500HPA REMAINS ZONAL.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
A WEAK COLD FRONT WILL GRADUALLY APPROACH FROM THE NORTH AND WEST
TODAY...TRIGGERING SCATTERED AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS.
AREAS OF MVFR/IFR CIGS AND VSBYS WILL PERSIST INTERMITTENTLY AT THE
TAF SITES THROUGH AROUND 14Z/THU...BEFORE GRADUALLY DISSIPATING.
THEN...SCATTERED SHOWERS/TSTMS WILL DEVELOP THIS AFTERNOON...MAINLY
AFTER 18Z. THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL GRADUALLY
DECREASE AFTER 02Z/FRI. AREAS OF MVFR/IFR CIGS AND VSBYS WILL LIKELY
DEVELOP ONCE AGAIN AFTER 06Z/FRI.
WINDS WILL BECOME SOUTH TO SOUTHWEST AT 5-10 KT THIS
AFTERNOON...THEN WILL BECOME LIGHT/VARIABLE ONCE AGAIN TONIGHT.
WINDS WILL BE MUCH STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR
ANY THUNDERSTORMS.
OUTLOOK...
FRI-SAT...MVFR/IFR. SHRA/TSRA LIKELY. AM LOW CLOUDS/FOG.
SAT NGT-MON...VFR. NO SIG WX.
&&
.FIRE WEATHER...
MINIMAL FIRE WEATHER CONCERNS AS INCREASING LOW LEVEL MOISTURE
ALONG WITH POTENTIAL FOR SHOWERS AND THUNDERSTORMS...ALONG WITH
HEAVY RAINFALL...WILL KEEP RELATIVE HUMIDITIES AT OR ABOVE 50
PERCENT THROUGH THE END OF THE WEEK.
&&
.HYDROLOGY...
A MODERATE TO SIGNIFICANT HEAVY RAINFALL EVENT REMAINS POSSIBLE
THROUGH FRIDAY NIGHT WITH A GENERAL 1-3 INCHES PER THE LATEST QPF
GUIDANCE WITH LOCALIZED AMOUNTS OF 3-4 INCHES POSSIBLE.
SCATTERED SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP
THURSDAY...WITH NUMEROUS SHOWERS AND STORMS EXPECT FRIDAY INTO
FRIDAY NIGHT AS A SERIES OF FRONTAL PASSAGES AND ANOMALOUS UPPER
LOW OVER THE MID WEST IMPACTS THE AREA.
IT IS STILL TOO EARLY TO DETERMINE WHERE THE HIGHEST PRECIPITATION
AMOUNTS WOULD BE....HOWEVER THERE REMAINS A CONCERN FOR POSSIBLE
FLASH FLOODING.
AS FAR AS MAIN STEM RIVERS GO...THERE COULD BE SIGNIFICANT WITHIN
BANK RISES ON SOME DEPENDING ON WHERE THE AXIS OF HEAVY RAINFALL
SETS UP. HOWEVER...GIVEN THE DRY CONDITIONS OF LATE...AT THIS
POINT...WIDESPREAD RIVER FLOODING APPEARS UNLIKELY.
DUE TO ALL THESE FACTORS MENTIONED ABOVE...WILL KEEP MENTION FOR THE
POSSIBILITY FOR HEAVY RAINFALL IN OUR HAZARDOUS WEATHER OUTLOOK.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/BGM
NEAR TERM...FRUGIS/BGM
SHORT TERM...BGM
LONG TERM...KL
AVIATION...KL
FIRE WEATHER...BGM
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1142 AM EDT THU AUG 9 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL SLOWLY MOVE TOWARD OUR AREA TODAY AND
TONIGHT. AN AREA OF LOW PRESSURE HOWEVER WILL THEN MOVE ACROSS THE
GREAT LAKES REGION AND INTO SOUTHEASTERN CANADA FRIDAY AND
SATURDAY. AN ASSOCIATED COLD FRONT WILL SLIDE ACROSS OUR REGION
SATURDAY, FOLLOWED BY WEAK HIGH PRESSURE SUNDAY THROUGH TUESDAY.
THE NEXT COLD FRONT IS FORECAST TO APPROACH FROM THE NORTHWEST
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK MID LEVEL IMPULSE, SOME H8 THETA E ADVECTION AND
INSTABILITY WITH DIMINISHING CIN WERE ENOUGH TO TRIGGER ISOLATED
CONVECTION FROM W OF MPO TO NEAR IAD LATE THIS MORNING. THE THETA
E ADVECTION SEEMS PROGGED MAINLY FOR OUR NORTHERN AND WESTERN
ZONES THIS AFTERNOON. THE IMPULSE SHOULD CLEAR US TO OUR SOUTHEAST
BY EARLY AFTERNOON AND PUT US INTO A REGION OF NVA, SO WE AREN`T
REALLY ENTHUSIASTIC ABOUT INGREDIENTS COMING TOGETHER TO CAUSE THE
KIND OF BLOSSOMING OF CONVECTION THAT THE 12Z RUN OF THE HRRR WAS
SHOWING. ON THE OTHER HAND, THE THETA E ADVECTION AND INSTABILITY
ARE REAL AND SOME MODERATE BULK SHEAR WILL BE ON OUR NORTHWESTERN
DOORSTEP BY 00Z. WE ARE STANDING PAT WITH THE CHANCE TO SLIGHT
CHANCE AFTERNOON POPS PUSHING FROM NORTHWEST TO AROUND THE I-95
CORRIDOR AT THIS TIME.
REGARDING TEMPERATURES, THE MORNING SOUNDINGS FROM IAD, APG AND
OKX SUPPORTED THE MAX TEMPERATURE FORECAST. COOLER TEMPERATURES
ALONG THE COAST THANKS TO THE SOUTH-SOUTHEAST SURFACE FLOW WERE
VERIFYING. THE ONLY CHANGE WE MADE WAS TO THE SOUTHERN POCONOS
WHERE THE TEMPERATURES WERE SIMILAR TO THOSE IN FAR NORTHWEST NJ.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
LINGERING CONVECTION IS FORECAST TO DRIFT EASTWARD THIS EVENING.
WE WILL MENTION A CHANCE OF SHOWERS AND THUNDERSTORMS FOR MUCH OF
OUR REGION, KEEPING ONLY A SLIGHT CHANCE NEAR THE COAST.
SCATTERED TO ISOLATED CONVECTION MAY PERSIST INTO THE LATE NIGHT
HOURS AS A MID LEVEL IMPULSE IN THE SOUTHWESTERLY FLOW LIFTS OVER
OUR REGION. ALSO, A SURFACE BOUNDARY FROM THE SOUTHWEST AND SOUTH
IS EXPECTED TO ARRIVE.
WITH HIGH HUMIDITY LEVELS, TEMPERATURES SHOULD DROP ONLY INTO THE
7OS TONIGHT, EXCEPT IN THE ELEVATED TERRAIN WHERE SOME READINGS IN
THE UPPER 60S ARE POSSIBLE. THE FRONTAL BOUNDARY AND LOW LEVEL
MOISTURE FROM ANY CONVECTION MAY CAUSE THE DEVELOPMENT OF SOME FOG
AND LOW CLOUDS LATE TONIGHT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THIS TIME FRAME LOOKS TO START ON THE ACTIVE SIDE /POTENTIALLY
LOCALLY HEAVY RAIN AND STRONG CONVECTION/ ALONG WITH HUMID
CONDITIONS, FOLLOWED BY A MORE CALMER TIME. THE OVERALL SYNOPTIC
SETUP IS COMPRISED OF A VIGOROUS SHORT WAVE AMPLIFYING INTO A
CLOSED LOW ACROSS THE GREAT LAKES AND SOUTHEASTERN CANADA. THIS
FEATURE THEN SHIFTS NORTHEASTWARD LATER FRIDAY AND SATURDAY. THIS
SYSTEM THOUGH MAY BE SLOW TO MOVE NORTHEASTWARD ESPECIALLY
DEPENDING ON HOW CLOSED OFF IT BECOMES. THERE DOES HOWEVER LOOK
LIKE ENOUGH OF A FLOW AND ENERGY UPSTREAM TO PUSH THE CLOSED LOW
NORTHEASTWARD AS WE GO THROUGH SATURDAY AND SUNDAY. THE PATTERN
THEN LOOKS TO TRANSITION TO MORE ZONAL /SOME TROUGHING HOLDING ON
THOUGH FROM THE GREAT LAKES INTO THE NORTHEAST/ WITH WEAK HIGH
PRESSURE BUILDING FROM THE UPPER OHIO VALLEY TO THE MID ATLANTIC.
THE NEXT COLD FRONT MAY THEN BE APPROACHING FROM THE NORTHWEST
WEDNESDAY.
FOR FRIDAY, AS THE UPPER-LEVEL TROUGH AMPLIFIES TO OUR NORTHWEST
AND CLOSES OFF, A DEEP SOUTHERLY FLOW WILL ALLOW MOISTURE TO
INCREASE /PW VALUES NEAR 2 INCHES/. THIS IN COMBINATION WITH A
SOMEWHAT STRONGER WIND FIELD AND LOWERING HEIGHTS ARRIVING WILL
RESULT IN AN INCREASE IN SHOWERS AND THUNDERSTORMS. THE SEVERE
THREAT WILL GENERALLY BE DETERMINED BY HOW MUCH HEATING OCCURS, AS
THE SHEAR IS FORECAST TO INCREASE TO ABOUT 20-30 KNOTS FRIDAY INTO
EARLY SATURDAY. IT APPEARS THAT AT LEAST A FEW SHOWERS AND
THUNDERSTORMS COULD BE ONGOING TO START FRIDAY ALTHOUGH THE
OVERALL COVERAGE SHOULD BE LIMITED AND MOSTLY ACROSS OUR WESTERN
ZONES. HOWEVER, POCKETS OF STRONGER HEATING MAY ALLOW FOR MORE
ROBUST CONVECTION TO DEVELOP. THERE IS SOME TIMING DIFFERENCES
WITH SOME GUIDANCE A BIT FASTER WITH THE ASSOCIATED SURFACE LOW
AND COLD FRONT.
FRIDAY LOOKS TO BE ACTIVE WITH SHOWERS AND THUNDERSTORMS
OCCURRING AT ANY TIME ALTHOUGH THE AFTERNOON AND AT NIGHT LOOKS TO
BE MORE FAVORED AS THE MAIN THRUST OF THE INCOMING SHARPENING
TROUGH ARRIVES. THE GUIDANCE INDICATES THAT THE MLCAPE VALUES
INCREASE UP TO 1500 J/KG FRIDAY GIVEN A WARM AND RATHER MOIST
AIR MASS. THIS MAY BECOME PROBLEMATIC THOUGH REGARDING THE SEVERE
WEATHER POTENTIAL AS SHOWERS AND STORMS MAY TEND TO DEVELOP
QUICKLY. IN ADDITION, THERE IS THE POTENTIAL FOR A FAIR AMOUNT OF
CLOUDS TO BE AROUND AND LIMITING THE OVERALL INSTABILITY. ANY MORE
ROBUST STORMS THAT CAN SUSTAIN THEMSELVES AND EVEN BECOME
ORGANIZED WILL INCREASE THE LOCALLY STRONG WIND THREAT /DOWNBURST
POTENTIAL DUE TO WATER LOADED DOWNDRAFTS APPEARS TO BE THE MAIN
THREAT/, ALTHOUGH SOME HAIL IS POSSIBLE IF CONVECTIVE ELEMENTS CAN
BECOME TALL ENOUGH. THE DEEP AND LOW-LEVEL SHEAR MAY BECOME
SOMEWHAT STRONGER IN ASSOCIATION WITH A MID LEVEL JET ROTATING
THROUGH THE SOUTHEASTERN PERIPHERY OF THE UPPER LOW. IF SUFFICIENT
INSTABILITY DEVELOPS, STORMS MAY BECOME A BIT MORE ORGANIZED WITH
THE POTENTIAL FOR BOWING SEGMENTS. IN ADDITION, THE POTENTIAL
EXISTS FOR THE LOW-LEVEL WINDS TO BACK MORE TO THE SOUTHEAST WHILE
ALOFT THEY ARE FROM THE SOUTHWEST, ADDING TO THE LOW-LEVEL SHEAR.
AGAIN IF ENOUGH INSTABILITY CAN DEVELOP AND BE MAINTAINED, SOME
CONVECTIVE ELEMENTS MAY BE ABLE TO DEVELOP SOME STORM ROTATION.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY VERY HEAVY RAIN AS
RAINFALL RATES SHOULD BE EFFICIENT. THE STEERING FLOW LOOKS TO BE
ABOUT 20 KNOTS THEREFORE THE SHOWERS AND STORMS WILL BE MOVING,
BUT WE MAY HAVE TO WATCH FOR TRAINING CELLS. FOR NOW, WE WILL
CONTINUE TO INCLUDE A POSSIBLE HEAVY RAIN MENTION IN THE FORECAST
BUT OPTED TO NOT INCLUDE OTHER ENHANCED WORDING ATTM DUE TO LOWER
CONFIDENCE REGARDING COVERAGE/INSTABILITY AND OVERALL STORM
EVOLUTION. A MENTION HOWEVER FOR THE POTENTIAL OF SOME SEVERE
STORMS WILL BE CONTINUED IN THE HAZARDOUS WEATHER OUTLOOK.
FOR SATURDAY, THE CLOSED LOW ALLOWS THE SURFACE LOW TO BE
CAPTURED NEAR THE EASTERN GREAT LAKES REGION WITH THE ASSOCIATED
COLD OR OCCLUDED FRONT SHIFTING OFF THE COAST WITH TIME. THIS WILL
BRING AN END TO THE SHOWERS AND THUNDERSTORMS DURING THE COURSE OF
THE DAY WITH THE MORNING BEING THE MOST ACTIVE AS OF NOW. A DRY
SLOT SHOULD BE WORKING INTO THE AREA DURING THE AFTERNOON AS THE
CLOSED LOW SLOWLY LIFTS NORTHEASTWARD. DESPITE THE CYCLONIC FLOW
PERSISTING THROUGH THE NIGHT, THE LACK OF APPRECIABLE LIFT SHOULD
KEEP ANY SHOWER THREAT RATHER LOW. IT SHOULD BE TURNING LESS HUMID
DURING THE COURSE OF THE AFTERNOON AS DRYING PUSHES IN FROM THE
WEST.
FOR SUNDAY AND MONDAY, THE AFOREMENTIONED CLOSED LOW GRADUALLY
LIFTS AWAY FROM OUR AREA WITH A TROUGH AXIS SLIDING ACROSS. THIS
KEEPS OUR AREA AT LEAST FOR SUNDAY WITHIN A CYCLONIC FLOW ALOFT
WHILE HIGH PRESSURE AT THE SURFACE BUILDS IN. THE MAIN COLD POOL
ALOFT LOOKS TO DRIFT FAR ENOUGH NORTH TO KEEP ANY SHOWERS REMOVED
FROM OUR REGION, ALTHOUGH THERE COULD BE ADDITIONAL CUMULUS
DEVELOPMENT DURING PEAK HEATING. AS AT LEAST SOME MIXING OCCURS
ALONG WITH AN AIR MASS CHANGE, DEW POINTS SHOULD BE LOWER TO
PROVIDE A MORE PLEASANT DAY. DESPITE THE MID LEVEL FLOW TURNING
MORE ZONAL LATE SUNDAY AND MONDAY, SOME GUIDANCE HINTS AT A SHORT
WAVE TRACKING SOUTHEASTWARD FROM THE MIDWEST. SOME CONVECTION MAY
BE TIED TO THIS AS SOME WAA AND MOISTURE ADVECTION OCCURS AHEAD OF
IT. FOR NOW, OPTED TO KEEP MONDAY DAY DRY AND CONTINUE SLIGHT CHC
POPS AT NIGHT.
FOR TUESDAY AND WEDNESDAY, WHILE THE FLOW TRIES TO MAINTAIN A
MORE ZONAL ORIENTATION IT APPEARS THAT THERE WILL BE SOME SHORT
WAVES EMBEDDED WITHIN THIS FLOW. THIS MAY TEAM UP OR ENHANCE SOME
WAA AHEAD OF IT WITH POSSIBLE ISOLATED TO SCATTERED CONVECTION AS
A RESULT. SOME OF THE GUIDANCE TENDS TO AMPLIFY AT LEAST ONE SHORT
WAVE SOME DURING THIS TIME FRAME WHICH RESULTS IN A HIGHER
CONVECTIVE POTENTIAL. AS OF NOW, WE DID NOT MAKE MUCH IN THE WAY
OF CHANGES AS TIMING OF THESE FEATURES IS MORE DIFFICULT THIS FAR
OUT. IF THERE IS LITTLE IN THE WAY OF TROUGH AMPLIFICATION AND THE
SHORT WAVE REMAINS WEAKER, THEN WE MAY HAVE TO WAIT FOR A COLD
FRONT TO APPROACH DURING WEDNESDAY FOR PERHAPS A BETTER CHC OF
CONVECTION. LITTLE CHANGES WERE MADE TO THE TEMPERATURES ATTM.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
INTO THE AFTERNOON HOURS, MAINLY VFR CONDITIONS ARE ANTICIPATED
WITH SOME SCATTERED CUMULUS DEVELOPING. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO FORM OVER THE TERRAIN OF
NORTHEASTERN PENNSYLVANIA EARLY THIS AFTERNOON AND THEY MAY EXPAND
TO THE SOUTH AND EAST. AS A RESULT, THERE IS THE POTENTIAL FOR A
MID TO LATE AFTERNOON SHOWER OR THUNDERSTORM AT KRDG AND KABE.
HOWEVER, THERE IS NOT ENOUGH FORECAST CONFIDENCE REGARDING THE
TIMING AND ACTUAL IMPACT AT THOSE TWO LOCATIONS TO INCLUDE THE
MENTION IN THE TAFS AT THIS POINT. A SOUTHERLY FLOW AT 5 TO 10
KNOTS IS EXPECTED.
SCATTERED TO ISOLATED SHOWERS AND THUNDERSTORMS ARE FORECAST TO
LINGER IN OUR REGION INTO TONIGHT. AGAIN, THE FORECAST CONFIDENCE
LEVEL IS NOT HIGH ENOUGH TO INCLUDE THEIR MENTION IN THE TAFS AT
THIS TIME.
WITH THE LOW LEVEL MOISTURE AND A SURFACE BOUNDARY LIFTING
NORTHWARD INTO OUR REGION LATE TONIGHT, SOME FOG AND LOW CLOUDS
ARE POSSIBLE.
OUTLOOK...
FRIDAY AND SATURDAY...SHOWERS AND THUNDERSTORMS WILL INCREASE
THROUGH THE DAY FRIDAY AND CONTINUE SATURDAY MORNING AS A COLD
FRONT APPROACHES AND THEN MOVES THROUGH THE REGION. VFR WILL
BECOME MVFR OR EVEN LOWER ESPECIALLY IF SHOWERS AND STORMS BECOME
RATHER WIDESPREAD. THE AIR MASS WILL BE RATHER HUMID AS WELL,
THEREFORE CEILINGS MAY REMAIN LOW ESPECIALLY FRIDAY NIGHT AND
EARLY SATURDAY MORNING. THE OVERALL CONDITIONS ARE EXPECTED TO
IMPROVE TO VFR DURING THE SATURDAY FROM WEST TO EAST.
SUNDAY AND MONDAY...VFR.
&&
.MARINE...
THE SOUTHERLY FLOW IS EXPECTED TO INCREASE INTO THE 10 TO 15 KNOT
RANGE FOR TODAY AND TONIGHT. WAVE HEIGHTS ON OUR OCEAN WATERS
SHOULD REMAIN IN THE 2 TO 3 FOOT RANGE. ON DELAWARE BAY, WAVE
HEIGHTS WILL LIKELY BE 2 FEET OR LESS.
OUTLOOK...
A VIGOROUS SYSTEM CLOSING OFF ACROSS THE GREAT LAKES AND UPPER
OHIO VALLEY WILL DRIVE A SURFACE LOW ACROSS THE EASTERN GREAT
LAKES FRIDAY INTO SATURDAY. AN ASSOCIATED COLD/OCCLUDED FRONT WILL
MOVE THROUGH OUR AREA SATURDAY. AHEAD OF THIS FEATURE, A SOUTHERLY
FLOW WILL OCCUR AND STRENGTHEN SOME AS THE PRESSURE GRADIENT
TIGHTENS. AN EXAMINATION OF THE 925 MB FORECAST WINDS REVEALS
25-30 KNOTS MOVES THROUGH FRIDAY NIGHT AND SATURDAY MAINLY AHEAD
OF AND ALONG THE COLD FRONT. THIS MAY RESULT IN A PERIOD OF
ADVISORY LEVEL GUSTS, AND THE SOUTHERLY FLOW WILL TEND TO BUILD
THE SEAS TO NEAR 5 FEET ON THE OCEAN. AS A RESULT, A SMALL CRAFT
ADVISORY MAY BE NEEDED FOR FRIDAY AND AT LEAST PART OF SATURDAY
BUT FOR NOW HELD OFF. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
BECOME MORE NUMEROUS DURING FRIDAY AND SATURDAY MORNING BEFORE
ENDING. SOME STORMS COULD BE CAPABLE OF PRODUCING LOCALLY GUSTY
WINDS.
A WEAK AREA OF HIGH PRESSURE THEN BEGINS TO BUILD INTO OUR REGION
SUNDAY AND MONDAY WITH A LIGHT WESTERLY WIND THAT MAY TURN
SOUTHERLY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...IOVINO/DELISI
SHORT TERM...IOVINO
LONG TERM...GORSE
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION
NWS MIAMI FL
1043 AM EDT THU AUG 9 2012
.UPDATE...THE LATEST HRRR SHOWS QUITE A BIT OF CONVECTION
DEVELOPING OVER THE INTERIOR AND ESPECIALLY THE GULF COAST/NAPLES
AREA THIS AFTERNOON. THE MIAMI SOUNDING THIS MORNING SHOWS
SUFFICIENT MOISTURE FOR CONVECTION...WITH A PWAT OF 1.62 INCHES
AND THE DRIEST AIR IN THE MID LEVELS. HAVE INCREASED THE COVERAGE
OF SHOWERS/TSTORMS FOR THE INTERIOR AND GULF COAST...WITH THE
HIGHEST POPS ACROSS THE NAPLES AREA. WEAK LAPSE RATES ARE PRESENT
BUT GIVEN STRONG HEATING AND MID LEVEL DRY AIR...A FEW STRONG
STORMS ARE POSSIBLE WHERE CONVERGENCE IS MAXIMIZED WHICH LOOKS TO
BE ACROSS THE GREATER NAPLES AREA LATE THIS AFTERNOON. STRONG WIND
GUSTS TO AROUND 50 MPH WOULD BE THE MAIN CONCERN IN THE STRONGEST
STORMS...AS WELL AS FREQUENT LIGHTNING. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 655 AM EDT THU AUG 9 2012/
AVIATION...
EASTERLY FLOW EXPECTED TO CONTINUE THROUGH THE PERIOD AT ALL EAST
COAST SITES WITH VFR CONDITIONS. KEPT VCTS MENTION AT KAPF AS A
WEAK GULF COAST SEA BREEZE COULD DEVELOP DURING THE EARLY
AFTERNOON HOURS RESULTING IN SCATTERED SHRA/TSTMS.
PREV DISCUSSION... /ISSUED 326 AM EDT THU AUG 9 2012/
SHORT TERM...TODAY THROUGH SATURDAY...A DEEP LAYER ATLANTIC
RIDGE SHOULD REMAIN ACROSS SOUTH CENTRAL FLORIDA TODAY AND
TONIGHT. WATER VAPOR IMAGES SHOW A RATHER DRY AIRMASS BEING
ADVECTED WESTWARD ACROSS THE NRN BAHAMAS AND THE SOUTHERN PORTIONS
OF THE PENINSULA BY THE DEEP EASTERLY FLOW AROUND THE BASE OF THIS
RIDGE. WL EXPECT THIS DRY AIR, COMBINED WITH SUBSIDENCE ALOFT, TO
KEEP PRECIP ACTIVITY TO A MINIMUM ACROSS MOST AREAS TODAY.
HOWEVER, LOCAL BREEZES AND DIURNAL HEATING COULD STILL LEAD TO THE
DEVELOPMENT OF A FEW SHWRS/TSTMS ACROSS INTERIOR PORTIONS LATER
THIS AFTERNOON. WL EXPECT THIS TO BE FOCUSED MORE TOWARD THE
WESTERN INTERIOR AND WEST OF LAKE OKEECHOBEE. PLENTY OF SUNSHINE
TODAY WILL ALSO LEAD TO AFTERNOON TEMPS SOARING INTO THE LOWER TO
MID 90S WITH HEAT INDICES AT OR ABOVE 100 DEGREES ACROSS MOST
AREAS, EXCEPT FOR THE IMMEDIATE EAST COAST.
A RATHER ACTIVE TROPICAL WAVE WAS LOCATED ACROSS THE CENTRAL
CARIBBEAN SEA EARLIER THIS MORNING MOVING WEST AT AROUND 10-15
KTS. AN UPPER LOW WAS ALSO INDICATED JUST NW OF JAMAICA AND
INTERACTING WITH THE WAVE. A LARGE ENVELOP OF MOISTURE WAS
ASSOCIATED WITH BOTH SYSTEMS. MOISTURE SHOULD BEGIN TO INCREASE
GRADUALLY OVER S. FLORIDA AS THE UPPER LOW MOVES TO THE WESTERN
TIP OF CUBE FRIDAY, BUT WILL BE FURTHER ENHANCED AS THE TROPICAL
WAVE MOVES ACROSS THE LOCAL AREA FRI NIGHT AND SATURDAY. DUE TO
THE NATURE OF THESE SYSTEMS AND THE COMPLEXITY OF THE INTERACTIONS
BETWEEN UPPER LOWS AND TROPICAL WAVES (BASED ON PAST EXPERIENCE),
DECIDED TO INCREASE THE CHANCES OF RAIN WITH CAUTION FOR BOTH
FRIDAY AND SATURDAY AND NOT GO AS HIGH AS GFS. IF THE RIGHT
COMBINATION, ENHANCED LOW LEVEL CONVERGENCE ASSOCIATED WITH THE
WAVE AND UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE LOW, COMES TO
PLAY, THE CHANCES FOR RAIN COULD BE SIGNIFICANTLY HIGHER.
LONG TERM...SUNDAY THROUGH WEDNESDAY...AN UPPER RIDGE SHOULD
BEGIN TO BUILD ACROSS THE REGION WHILE A LOW LEVEL ATLANTIC RIDGE
IS EXPECTED TO BUILD WESTWARD. THIS WILL TO LIMIT THE PRECIP
ACTIVITY BY WAY OF MID/UPPER LVL SUBSIDENCE AND WILL TEND TO FOCUS
AFTERNOON SHWRS/TSTMS MORE TOWARD INTERIOR AND WESTWARD PORTIONS
OF S. FLORIDA. NIGHTTIME AND EARLY MORNING PRECIP ACTIVITY COULD
ALSO OCCUR ALONG EASTERN AREAS.
MARINE...A LIGHT TO MODERATE SE FLOW SHOULD PREVAIL THROUGH THE
END OF THE WEEK WITH A SHIFT TO MORE SOUTHERLY BY THE WEEKEND.
SEAS ARE EXPECTED TO BE BELOW 4 FT THROUGH THE PERIOD.
HOWEVER...BOTH SEAS AND WINDS COULD BE SIGNIFICANTLY HIGHER IN THE
VICINITY OF SHOWERS AND THUNDERSTORMS...ESPECIALLY FRI NIGHT AND
SATURDAY AS THE TROPICAL WAVE MOVES THROUGH.
FIRE WEATHER...NO CONCERNS AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 79 89 75 / 20 20 50 40
FORT LAUDERDALE 91 80 88 75 / 20 20 50 50
MIAMI 91 79 89 76 / 20 20 50 50
NAPLES 93 77 91 76 / 50 20 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1046 AM EDT THU AUG 9 2012
.SYNOPSIS...
A STALLED FRONT WILL BE THE FOCUS FOR SHOWERS AND STORMS TODAY. A
MUCH LARGER SYSTEM WILL CONTINUE THE THREAT FOR ACTIVITY ON FRIDAY
AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STILL AT ODDS DETERMINING WHAT WILL HAPPEN WITH PRECIPITATION AND
SEVERE POSSIBILITIES FOR TODAY. A COUPLE OF STORMS ARE CURRENTLY
PASSING THROUGH EASTERN OHIO AND NORTHERN PENNSYLVANIA...BUT
DIFFICULTY WILL LIE IN WHERE PRECIPITATION WILL OCCUR DURING THE
AFTERNOON. HARD TO SAY WHETHER CONVECTION WILL REMAIN SCATTERED
AND MULTICELLED...SIMILAR TO THE 00Z NCEP WRF NMM/ARW...OR WHETHER
A LINE WILL DEVELOP IN OHIO AND MOVE TO THE EAST...AS SHOWN IN
SEVERAL HRRR RUNS AND THE 12Z NAM. IN EITHER SCENARIO...WITH
HIGHEST SHEAR VALUES EXPECTED TO REMAIN FARTHER NORTH ACROSS
EXTREME NORTHEASTERN OHIO...EXTREME NORTHWESTERN
PENNSYLVANIA...AND WESTERN NEW YORK...THIS MAY LIMIT SEVERE
POSSIBILITIES. OF COURSE...SKIES REMAINING CLEAR SOUTH AND EAST OF
PITTSBURGH WILL INCREASE INSTABILITY VALUES IN THAT AREA...EVEN IF
SHEAR VALUES REMAIN LOW. WITH BEST SHEAR TO THE NORTH AND BEST
INSTABILITY TO THE SOUTH...MAY JUST END UP WITH NON-SEVERE
THUNDERSTORMS. LOW CONFIDENCE FORECAST FOR THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
AN LARGE UL LOW WILL MOVER OVER LOWER MI TONIGHT. THIS SYSTEM WILL
DEVELOP A SFC LOW ALONG THE BOUNDARY AND FORCE THE BOUNDARY BACK
NORTHWARD TONIGHT. THE TRAILING COLD FRONT WILL MOVE INTO W OHIO
LATE TONIGHT AS THE 50 LOW DEEPENS AND MOVES SLOWLY EASTWARD.
EXPECT TO SEE A BREAK IN THE ACTIVITY THIS EVENING, AS THE SFC AND
UL LOW WILL BECOME THE FOCAL POINT AND THE UPPER OHIO VALLEY WILL
BE IN THE WARM SECTOR. AS THE ENTIRE SYSTEM MOVES EASTWARD,
EXPECT MORE SHOWERS AND STORMS TO BEGIN TO MOVE BACK INTO THE AREA
LATE TONIGHT.
THE SYSTEM WILL OCCLUDE FRIDAY MORNING AND SLOWLY MOVE EASTWARD.
THE SFC FRONT WILL SPIN THROUGH FRIDAY AFTERNOON. EXPECT A WET
FRIDAY WITH BELOW NORMAL TEMPS.
ENTIRE SYSTEM WILL MOVE TOWARD THE NORTHERN GREAT LAKES ON
SATURDAY. MOISTURE AND UL WAVES WILL ROTATE AROUND THE EXITING
SYSTEM, KEEPING IN CLOUDS, COOL TEMPS AND THE RISK FOR SHOWERS
THROUGH SAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WRAPAROUND PRECIPITATION SHOULD BE SHIFTING TO THE NORTH BY
SATURDAY EVE. HIGH PRESSURE WILL BUILD IN ON SUNDAY AND MOVE
THROUGH ON MONDAY. LATEST GFS CONTINUES TO SHOW A WEAK SYSTEM
MOVING THROUGH BY THE MIDDLE OF NEXT WEEK. WILL INCLUDE THE
MENTION OF PRECIP AT THIS TIME.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
UPSTREAM CONVECTION AHEAD OF ANOTHER SHORT WAVE IN WESTERN OHIO
IS LIKELY TO FALL APART BEFORE REACHING THE TERMINALS...LEAVING A
TREMENDOUS AMOUNT OF MID-LEVEL CONVECTIVE DEBRIS CLOUD OVER MUCH
OF THE AREA THROUGH AT LEAST THE EARLY AFTERNOON. AS
SUCH...PREVIOUS PROB30S FOR THUNDER THIS AFTERNOON WERE NOT
UPGRADED OR ENHANCED AS THUNDERSTORM DEVELOPMENT CHANCES SEEM TO
BE LOWER THAN PREVIOUSLY ANTICIPATED. FRIES
.OUTLOOK...FRIDAY THROUGH MONDAY...
RESTRICTIONS CAN BE EXPECTED IN WIDESPREAD SHOWERS AND
THUNDERSTORMS FRIDAY INTO FRIDAY NIGHT...WITH MORE ISOLATED
COVERAGE EXPECTED SATURDAY AND SATURDAY NIGHT. SUNDAY AND MONDAY
SHOULD SEE A RETURN TO VFR CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
1026 AM EDT THU AUG 9 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE OHIO VALLEY
TODAY...WITH A WEAK UPPER TROUGH MOVING ACROSS THE AREA THIS
AFTERNOON. THE FRONT WILL SLOWLY CROSS THE REGION LATE FRIDAY
INTO SATURDAY. HIGH PRESSURE WILL SETTLE ACROSS THE REGION SUNDAY
THROUGH MONDAY...BEFORE ANOTHER COLD FRONT AFFECTS THE REGION
THROUGH THE MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
ATMOSPHERIC DESTABILIZATION IS UNDERWAY WITH MOST LOCALES BREAKING
OUT OF THE FOG/LOW CLOUDS FROM EARLIER THIS MORNING. CLUSTER OF
SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER NORTHERN MARYLAND
HAS EXPANDED AND WILL MOVE EAST ACROSS NORTHERN VIRGINIA.
ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY CAN BE EXPECTED THIS
AFTERNOON AS DAYTIME HEATING COMBINES WITH DECENT MOISTURE AND AN
APPROACHING TROUGH. THERE REMAINS A THREAT FOR STRONG TO SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING WITH HIGH CAPE ENVT BUT
SHEAR REMAINS WEAK. STORM MOTION WILL BE SLOW WITH HEAVY DOWNPOURS
AND LOCALIZED FLOODING A CONCERN.
NEAR-TERM MODELS ARE ALSO COLLECTIVELY KEYING-IN ON BASICALLY ONE
LINE OR BROKEN LINE OF CONVECTION THAT MOVES ACROSS THE AREA OVER
THE COURSE OF THE AFTN/EARLY EVE...W/ VERY LITTLE IMMEDIATELY
BEHIND IT - THOUGH THE HRRR DOES CONTINUALLY DEVELOP CELLS BACK
INTO WV MOST OF THE DAY. THIS SOLUTION DOES LINE-UP W/ THE
FORECAST FOR A LEE TROUGH TO MOVE ACROSS THE AREA THIS AFTN...THE
PRECURSOR TO THE INCOMING LOW PRESSURE SYSTEM ON FRIDAY - THESE
FEATURES WILL AFFECT THE AREA ABOUT A DAY APART.
THERE WILL BE ENOUGH LIFT BEHIND THE INITIAL LEE TROUGH PASSAGE
AND THE INCOMING LOW PRESSURE SYSTEM TO DEVELOP SCATTERED BATCHES
OF SHOWER ACTIVITY WELL INTO THE OVERNIGHT HRS. IT WILL STILL BE
WARM TONIGHT - EVEN W/ OVERCAST SKIES AND SCATTERED SHOWERS SINCE
THE HUMIDITY LEVELS WILL STAY FAIRLY HIGH.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
UPPER LEVEL LOW PRESSURE PROGRESSES INTO THE GREAT LAKES AREA BY
EARLY FRIDAY. A DEEP SOUTHERLY FLOW REMAINS IN PLACE EARLY FRIDAY AS
THE COLD FRONT CROSSES THE CENTRAL APPALACHIANS. THE GFS IS A LITTLE
FASTER WITH THE TIMING OF THE FRONT THROUGH THE DC AREA...WHILE THE
NAM REMAINS CONSISTENT BRINGING IT IN FRIDAY EVENING. THERE WILL BE
DECENT MID LEVEL FRONTOGENESIS BACK OUT TOWARD W VA AHEAD OF THE
UPPER TROF. SPC KEEPS US IN A SLIGHT RISK FOR SEVERE STORMS FRIDAY
GIVEN UNCERTAINTY IN CLOUD COVER AND MARGINAL SHEAR. A PERIOD OF
LOCALLY HEAVY RAINFALL IS LIKELY FRIDAY AFTERNOON AND EVENING WITH
ISOLATED STRONG TO SEVERE THUNDERSTORMS. TEMPERATURES IN THE MID 80S
ARE EXPECTED IN THE METRO AREAS WITH MUGGY DEW POINTS NEAR 70
DEGREES. BEHIND THE FRONT A DRIER NORTHWEST FLOW DEVELOPS. BOTH THE
NAM AND GFS HAVE THE PRECIPITATION BAND PUSHING EAST OF OUR AREA BY
18Z SATURDAY. WE ARE CARRYING CHANCES OF SHOWERS ABOUT 6 HOURS BEHIND
THIS TO ACCOUNT FOR THE POSSIBILITY OF EARLIER MODEL RUNS THAT THE
FRONT WOULD HANG UP ACROSS OUR AREA...CERTAINLY POSSIBLE THIS TIME
OF YEAR. COOLER TEMPERATURES ARE LIKELY SATURDAY IN EITHER EVENT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE GFS AND ECMWF BRING A TROF INTO THE INLAND PACIFIC NORTHWEST BY
THE END OF THIS PERIOD WITH A RIDGE REPLACING THE TROF CURRENTLY
OVER MINNESOTA. THIS TELECONNECTS TO A WEAKER TROF OVER THE EASTERN
U.S. AS THE OLD GREAT LAKES TROF EJECTS INTO EASTERN CANADA. SUNDAY
LOOKS LIKE A NICE DAY WITH TEMPERATURES IN THE MID 80/S AND DEW
POINTS IN THE 60/S. THE HUMIDITY BEGINS TO RETURN MONDAY AND
TUESDAY WITH THE APPROACH OF THE NEXT UPSTREAM TROF AND AN
INCREASING SOUTHERLY FLOW. TEMPERATURES RISE BACK INTO THE LOWER
90S BY MONDAY WITH A CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS.
THIS THREAT SPREADS INTO THE METRO AREAS TUESDAY AND WEDNESDAY.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
MOST OF THE FOG HAS MIXED OUT. SCATTERED SHOWERS AND THUNDERSTORMS
WILL PERSIST THROUGH EARLY EVENING WITH OCCASIONAL REDUCTIONS IN VSBY
AND CIGS TO MVFR. SOME OF THE STORMS COULD CONTAIN STRONG GUSTY
WINDS AOA 40 KTS...SMALL HAIL AND HEAVY DOWNPOURS. PATCHY FOG
WILL REDEVELOP OVERNIGHT INTO EARLY FRIDAY.
POTENTIALLY SEVERE THUNDERSTORMS PROGRESS NORTHEAST THROUGH THE MID
ATLANTIC FRIDAY WITH HEAVY RAIN AND POSSIBLE STRONG WINDS. THE
COLD FRONT STALLS OVER CHESAPEAKE BAY REGION SATURDAY...WITH HIGH
PRESSURE AND MAINLY VFR CONDITIONS EXPECTED SUNDAY AND MONDAY.
&&
.MARINE...
SLY WINDS WILL BEGIN TO CHANNEL AND STRENGTHEN LATER THIS AFTN. A
SCA REMAINS IN EFFECT FOR THE BAY - MAINLY THE MAIN CHANNEL. THE
PEAK WILL BE THIS EVENING AND INTO THE LATE NIGHT HRS...THEN
GRADUALLY SUBSIDE FROM NORTH- TO-SOUTH. SHOWERS AND TSTMS ARE ALSO
EXPECTED TO DEVELOP OFF THE WEST LATER THIS AFTN AND APPROACH THE
WATERS...CREATING GUSTY WINDS IN LOCALIZED AREAS.
SOUTHERLY CHANNELING WILL DEVELOP FRIDAY WITH WIND SPEEDS
APPROACHING 15 KTS. WINDS WILL BECOME LOCALLY GUSTY OVER THE
WATERS IN THUNDERSTORMS FRIDAY WITH REDUCED VISIBILITIES IN HEAVY
DOWNPOURS. A SMALL CRAFT ADVISORY MAY BE NEEDED FRIDAY WITH GUSTY
WINDS FROM THUNDERSTORMS INTO FRIDAY NIGHT. FRONT STALLS WITH
CONTINUED SHOWERS AND THUNDERSTORMS SATURDAY. HIGH PRESSURE AND
FAIR WEATHER IS EXPECTED SUNDAY AND MONDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EDT
THIS EVENING FOR ANZ530>533-537>542.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM EDT
FRIDAY FOR ANZ534-543.
&&
$$
SYNOPSIS...GMS
NEAR TERM...KRW
SHORT TERM...GMS
LONG TERM...SDG
AVIATION...KRW/GMS
MARINE...KRW/GMS
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
746 AM EDT THU AUG 9 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE OHIO VALLEY
TODAY...WITH A WEAK UPPER TROUGH MOVING ACROSS THE AREA THIS
AFTERNOON. THE FRONT WILL SLOWLY CROSS THE REGION LATE FRIDAY
INTO SATURDAY. HIGH PRESSURE WILL SETTLE ACROSS THE REGION SUNDAY
THROUGH MONDAY...BEFORE ANOTHER COLD FRONT AFFECTS THE REGION
THROUGH THE MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SCATTERED SHOWERS HAVE BEGUN TO TAKE SHAPE OVER NORTHERN
MARYLAND...PARTICULARLY ALLEGANY AND WASHINGTON COUNTIES. EXPECT
COVERAGE TO INCREASE ONCE THE FOG/HAZE/LOW CLOUDS MIX OUT AND
DESTABILIZATION BEGINS TO OCCUR. A MOIST ATMOSPHERE COMBINED WITH
HEATING AND AN APPROACHING TROUGH ALL POINT TO AN UPTICK IN
CONVECTIVE ACTIVITY TODAY. MADE ADJUSTMENTS TO INCREASE
POPS/INCREASE SKY GRIDS AND TO ADD MORE COVERAGE OF FOG EARLY
THIS MORNING. WILL ALSO FURTHER INVESTIGATE HIGH TEMPERATURES THIS
AFTERNOON GIVEN INCREASING CLOUDS APPROACHING FROM THE WEST.
LOCAL HI-RES GUIDANCE DEVELOPS SCATTERED TSTMS ALONG THE HIGHER
TERRAIN AND MOVES THEM EWD UNDER THE MOST PRONOUNCED MID-LEVEL
STEERING FLOW WE`VE SEEN IN THE PAST FEW DAYS. THESE NEAR-TERM
MODELS ARE ALSO COLLECTIVELY KEYING-IN ON BASICALLY ONE LINE OR
BROKEN LINE OF CONVECTION THAT MOVES ACROSS THE AREA OVER THE
COURSE OF THE AFTN/EARLY EVE...W/ VERY LITTLE IMMEDIATELY BEHIND
IT - THOUGH THE HRRR DOES CONTINUALLY DEVELOP CELLS BACK INTO WV
MOST OF THE DAY. THIS SOLUTION DOES LINE-UP W/ THE FORECAST FOR A
LEE TROUGH TO MOVE ACROSS THE AREA THIS AFTN...THE PRECURSOR TO
THE INCOMING LOW PRESSURE SYSTEM ON FRIDAY - THESE FEATURES WILL
AFFECT THE AREA ABOUT A DAY APART. MODEST INSTABILITY WILL ALLOW
FOR MORE ISOLATED/SCATTERED TSTMS W/ LOCALIZED HEAVY RAIN...GUSTY
WINDS AND HAIL.
ASSUMING THE EARLIER TSTM ACTIVITY CUTS DOWN ON THE INSTABILITY
THIS AFTN W/ LITTLE RECOVERY TIME TILL THE OVERNIGHT
HRS...CONVECTIVE CHANCES WILL DROP OFF TO A MORE ISOLATED/EMBEDDED
NATURE FOR ANY OVERNIGHT PRECIP ACTIVITY. THERE WILL BE ENOUGH
LIFT BEHIND THE INITIAL LEE TROUGH PASSAGE AND THE INCOMING LOW
PRESSURE SYSTEM TO DEVELOP SCATTERED BATCHES OF SHOWER ACTIVITY
WELL INTO THE OVERNIGHT HRS. IT WILL STILL BE WARM TONIGHT - EVEN
W/ OVERCAST SKIES AND SCATTERED SHOWERS SINCE THE HUMIDITY LEVELS
WILL STAY FAIRLY HIGH.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
UPPER LEVEL LOW PRESSURE PROGRESSES INTO THE GREAT LAKES AREA BY
EARLY FRIDAY. A DEEP SOUTHERLY FLOW REMAINS IN PLACE EARLY FRIDAY AS
THE COLD FRONT CROSSES THE CENTRAL APPALACHIANS. THE GFS IS A LITTLE
FASTER WITH THE TIMING OF THE FRONT THROUGH THE DC AREA...WHILE THE
NAM REMAINS CONSISTENT BRINGING IT IN FRIDAY EVENING. THERE WILL BE
DECENT MID LEVEL FRONTOGENESIS BACK OUT TOWARD W VA AHEAD OF THE
UPPER TROF. SPC KEEPS US IN A SLIGHT RISK FOR SEVERE STORMS FRIDAY
GIVEN UNCERTAINTY IN CLOUD COVER AND MARGINAL SHEAR. A PERIOD OF
LOCALLY HEAVY RAINFALL IS LIKELY FRIDAY AFTERNOON AND EVENING WITH
ISOLATED STRONG TO SEVERE THUNDERSTORMS. TEMPERATURES IN THE MID 80S
ARE EXPECTED IN THE METRO AREAS WITH MUGGY DEW POINTS NEAR 70
DEGREES. BEHIND THE FRONT A DRIER NORTHWEST FLOW DEVELOPS. BOTH THE
NAM AND GFS HAVE THE PRECIPITATION BAND PUSHING EAST OF OUR AREA BY
18Z SATURDAY. WE ARE CARRYING CHANCES OF SHOWERS ABOUT 6 HOURS BEHIND
THIS TO ACCOUNT FOR THE POSSIBILITY OF EARLIER MODEL RUNS THAT THE
FRONT WOULD HANG UP ACROSS OUR AREA...CERTAINLY POSSIBLE THIS TIME
OF YEAR. COOLER TEMPERATURES ARE LIKELY SATURDAY IN EITHER EVENT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE GFS AND ECMWF BRING A TROF INTO THE INLAND PACIFIC NORTHWEST BY
THE END OF THIS PERIOD WITH A RIDGE REPLACING THE TROF CURRENTLY
OVER MINNESOTA. THIS TELECONNECTS TO A WEAKER TROF OVER THE EASTERN
U.S. AS THE OLD GREAT LAKES TROF EJECTS INTO EASTERN CANADA. SUNDAY
LOOKS LIKE A NICE DAY WITH TEMPERATURES IN THE MID 80/S AND DEW
POINTS IN THE 60/S. THE HUMIDITY BEGINS TO RETURN MONDAY AND
TUESDAY WITH THE APPROACH OF THE NEXT UPSTREAM TROF AND AN
INCREASING SOUTHERLY FLOW. TEMPERATURES RISE BACK INTO THE LOWER
90S BY MONDAY WITH A CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS.
THIS THREAT SPREADS INTO THE METRO AREAS TUESDAY AND WEDNESDAY.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
PATCHY FOG EXPECTED ACROSS THE AREA...THOUGH ONLY BRIEFLY DENSE
TOWARD SUNRISE IN LOCALIZED AREAS. MOSTLY CLR THIS MRNG...THOUGH
CUMULUS DECKS WILL BEGIN TO DEVELOP EARLY AFTN. SCATTERED SHOWERS
AND TSTMS WILL DEVELOP THIS MORNING AND MOVE EAST FROM THE MTNS
OVER THE COURSE OF THE AFTN AND INTO EARLY EVNG. METRO AREAS COULD
SEE THIS ACTIVITY TOWARD LATE AFTN...W/ A LULL PERIOD FOR THE LATE
NIGHT HRS. SCATTERED SHOWERS POSSIBLE OVERNIGHT.
POTENTIALLY SEVERE THUNDERSTORMS PROGRESS NORTHEAST THROUGH THE MID
ATLANTIC FRIDAY WITH HEAVY RAIN AND POSSIBLE STRONG WINDS. THE
COLD FRONT STALLS OVER CHESAPEAKE BAY REGION SATURDAY...WITH HIGH
PRESSURE AND MAINLY VFR CONDITIONS EXPECTED SUNDAY AND MONDAY.
&&
.MARINE...
LIGHT WINDS OVERNIGHT...MAINLY SWLY. A LOW PRESSURE SYSTEM WILL
APPROACH TODAY FROM THE NW AND INCREASE THE SFC PRES GRADIENT UP
AGAINST THE LARGE BERMUDA HIGH OFF THE COAST. SLY WINDS WILL BEGIN
TO CHANNEL AND STRENGTHEN LATER THIS AFTN. A SCA IS NOW POSTED FOR
THE BAY - MAINLY THE MAIN CHANNEL. THE PEAK WILL BE THIS EVENING
AND INTO THE LATE NIGHT HRS...THEN GRADUALLY SUBSIDE FROM NORTH-
TO-SOUTH. SHOWERS AND TSTMS ARE ALSO EXPECTED TO DEVELOP OFF THE
WEST LATER THIS AFTN AND APPROACH THE WATERS...CREATING GUSTY
WINDS IN LOCALIZED AREAS.
SOUTHERLY CHANNELING WILL DEVELOP FRIDAY WITH WIND SPEEDS
APPROACHING 15 KTS. WINDS WILL BECOME LOCALLY GUSTY OVER THE
WATERS IN THUNDERSTORMS FRIDAY WITH REDUCED VISIBILITIES IN HEAVY
DOWNPOURS. A SMALL CRAFT ADVISORY MAY BE NEEDED FRIDAY WITH GUSTY
WINDS FROM THUNDERSTORMS INTO FRIDAY NIGHT. FRONT STALLS WITH
CONTINUED SHOWERS AND THUNDERSTORMS SATURDAY. HIGH PRESSURE AND
FAIR WEATHER IS EXPECTED SUNDAY AND MONDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EDT
THIS EVENING FOR ANZ530>533-537>542.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM EDT
FRIDAY FOR ANZ534-543.
&&
$$
SYNOPSIS...GMS
NEAR TERM...KRW/GMS
SHORT TERM...GMS
LONG TERM...SDG
AVIATION...GMS/KRW
MARINE...GMS/KRW
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
752 AM EDT THU AUG 9 2012
.SYNOPSIS...
ISSUED AT 321 AM EDT THU AUG 9 2012
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL BRING RAIN AND UNSEASONABLY
COOL WEATHER TODAY THROUGH FRIDAY. HIGH TEMPERATURES WILL ONLY REACH
THE MID 60S TO MID 70S TODAY AND FRIDAY. IT WILL ALSO BECOME RATHER
BREEZY LATE TONIGHT THROUGH FRIDAY. A FEW LIGHTER SHOWERS MAY LINGER
INTO SATURDAY BUT MOST OF THE WEEKEND SHOULD BE DRY.
&&
.UPDATE...
ISSUED AT 750 AM EDT THU AUG 9 2012
I UPDATED THE GRIDS TO TRACK THE AREA OF CONVECTION NEAR JACKSON
OUT AN BRING THE AREA OF RAIN NORTH OF MKG IN. I KEPT KEPT THE
TREAT OF THUNDERSTORMS THIS AFTERNOON DUE TO THE STRENGTH OF THE
DYNAMICS WITH THIS DIGGING SYSTEM AND THE DEVELOPING MID LEVEL JET
SEGMENT SHOWN BY THE LATEST RAP (09Z) OVER CENTRAL LOWER MICHIGAN
AFTER 18Z CAUSING COUPLING WITH THE EXIT REGION OF THE JET
SEGMENT DIVING INTO IL AT THAT TIME. THIS SHOULD HELP PULL MID
LEVEL UNSTABLE AIR NORTH OVER THE EASTERN CWA LATE THIS AFTERNOON.
THE HEAVY RAIN THREAT WILL HAVE TO BE WATCHED... I COULD SEE A NEED
FOR URBAN AND SMALL STREAM FLOODING ADVISORIES BY THIS EVENING AS
THE RAIN BAND COMES TOGETHER OVER OUR CWA.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON)
ISSUED AT 321 AM EDT THU AUG 9 2012
AN UPPER LEVEL LOW PRESSURE SYSTEM IN CONJUNCTION WITH AN
INTENSIFYING SFC LOW TRACKING NE ACROSS OHIO TONIGHT WILL BRING RAIN
AND UNSEASONABLY COOL CONDITIONS TODAY THROUGH FRIDAY. MAX TEMPS
TODAY WILL ONLY REACH THE UPPER 60S TO MID 70S. IT WILL BE EVEN
COOLER FRIDAY WITH STRONG NORTH WINDS... EXTENSIVE LOW CLOUDS AND
SHOWERS. MAX TEMPS FRIDAY WILL ONLY REACH THE MID 60S TO NEAR 70.
MAINTAINING VERY HIGH (CATEGORICAL) POPS FOR RAIN TODAY THROUGH
TONIGHT. LOCALLY HEAVY RAIN IS POSSIBLE WITH DEEP MOISTURE IN PLACE
AND HIGH PRECIPITABLE WATER VALUES. ON AVERAGE A GENERAL ONE TO TWO
INCH TYPE RAINFALL IS LIKELY FOR MOST OF OUR FCST AREA FROM TODAY
THROUGH FRIDAY BUT A FEW HIGHER TOTALS ARE POSSIBLE. MOST (IF NOT
ALL) CONVECTIVE DEVELOPMENT TODAY THROUGH TONIGHT SHOULD STAY SOUTH
OF OUR FCST AREA ACROSS IN/OH WHERE SOME DECENT SFC/ELEVATED
INSTABILITY WILL DEVELOP LATER TODAY THROUGH TONIGHT.
EXTENSIVE CLOUD COVER WILL LIKELY LINGER ON SATURDAY BUT ANY
LINGERING LIGHTER SHOWERS SHOULD GRADUALLY TAPER OFF AS THE UPPER
TROF AXIS SHIFTS A LITLE FURTHER ENE AWAY FROM OUR REGION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 321 AM EDT THU AUG 9 2012
THERE WILL BE SLOW WARMING TREND UNTIL THE NEXT SYSTEM COMES THROUGH
LATE IN THE WEEK. COULD BE AN ACTIVE THUNDERSTORM EVENT LATE WEEK
WITH THE FRONT.
THE MODELS DO AGREE OVER ALL ON THE LARGE SCALE UPPER WAVE PATTERN.
THAT IS THE SOUTHERN BRANCH OF THE POLAR JET SLOWLY DIGS SOUTH OVER
THE WESTERN CONUS THROUGH AT LEAST WEDNESDAY. THAT IN TURN RESULTS
IN RISING HEIGHTS OVER THE CENTRAL CONUS INTO MID WEEK. THIS ALL
HAPPENS DUE TO THE STORM SYSTEM THAT IS CURRENTLY NEAR THE NORTH
POLE DIGGING SOUTH SOUTHEAST INTO WESTERN AND CENTRAL CANADA DURING
THIS SAME TIME(SUNDAY INTO WEDNESDAY). THAT RESULTS IN THE LARGE
UPPER HIGH THAT HAS BEEN CAUSING ALL THE HOT WEATHER FOR THE PAST
FEW MONTHS... OVER MOST OF THE CONUS... TO FINALLY BE SQUASHED AND
SHIFTED TO THE GULF OF MEXICO BY WEDNESDAY. THE RISING HEIGHTS WOULD
MEAN WARMER TEMPERATURES HEAR AGAIN (BUT JUST FOR A SHORT TIME).
AS I WROTE YESTERDAY THROUGH... LARGE SCALE CHANGES IN THE PLANETARY
WAVE PATTERN ARE CURRENTLY UNDERWAY. I DO NOT EXPECT ANOTHER BIG
HEAT WAVE FROM THIS WARM UP. A STRONG COLD FRONT FOLLOWS LATE IN THE
WEEK. THAT WILL BE PROCEEDED BY THUNDERSTORMS. HOWEVER THAT WILL BE
JUST BEYOND OUR CURRENT FORECAST PERIOD. THE EVENT LATE WEEK COULD
BE A SIGNIFICANT STORM EVENT FROM WHAT BOTH THE GFS AND ECMWF
SUGGEST. REMEMBER WE HAVE A POLAR LOW DIGGING SOUTH THAT MAY PHASE
WITH PACIFIC STORM IN THAT TIME FRAME.
AS FOR THE DAY TO DAY...OUR CLOSED UPPER LOW SHOULD BE DEPARTING THE
WESTERN GREAT LAKES SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE WILL
BRING SUNSHINE AND TYPICAL MID AUGUST TEMPERATURES. A WEAK SYSTEM
WILL MOVE THROUGH THE WESTERN GREAT LAKES IN THE MONDAY TIME FRAME.
THAT SYSTEM IS CURRENTLY MOVING ON SHORE OVER THE WESTERN CONUS AND
IS THE KICKER THAT HELPS TO BOOT THE UPPER LOW OUT OF THE GREAT
LAKES. THE MODELS ARE STRUGGLING WITH IT BUT NO MATTER... IT IS WEAK
SYSTEM AND SHOULD HAVE A LIMITED IMPACT TO SOUTHWEST MICHIGAN
WEATHER IN THE MONDAY TIME FRAME...ISOLATED SHOWERS AT BEST.
THE REAL WARM UP WILL BE TUESDAY AND WEDNESDAY. STORMS WILL
FOLLOW... OF COURSE THERE IS ALWAYS TIMING ISSUES WITH SUCH FRONTS
BUT WE WILL HAVE TO WATCH THIS ONE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 750 AM EDT THU AUG 9 2012
THE CONVECTION OVER JXN WILL DEPART BY 13Z... MORE LIKELY BY 1215Z
ACTUALLY. THE BKN005 CIGS AT LAN SHOULD BE GONE BY 13Z TOO AS NO
OTHER SITES HAVE THAT SORT OF CEILING NEAR THERE.
FOR THE MOST PART I EXPECT VFR CIGS/VSBY MOST OF THE REST OF THE
MORNING AT OUR TAF SITES. AS THE STORM STARTS TO COME TOGETHER MID
TO LATE AFTERNOON ALL TAF SITES SHOULD SEE MVFR TO IFR VSBY AND
IFR CIGS. THAT WILL CONTINUE INTO FRIDAY AFTERNOON AS THE STORM
CONTINUES TO DEVELOP.
&&
.MARINE...
ISSUED AT 321 AM EDT THU AUG 9 2012
WINDS AND WAVES WILL RAMP UP SIGNIFICANTLY TONIGHT THROUGH FRIDAY.
WATERSPOUTS ARE ALSO POSSIBLE BY THIS AFTERNOON THROUGH TONIGHT INTO
FRIDAY.
&&
.HYDROLOGY...
ISSUED AT 321 AM EDT THU AUG 9 2012
CUMULATIVE RAINFALL TOTALS FROM TODAY THROUGH FRIDAY OF AN INCH OR
TWO ARE LIKELY ACROSS MUCH OF OUR FCST AREA. NO SIGNIFICANT HYDRO
ISSUES ARE ANTICIPATED THOUGH GIVEN LOW RIVER LEVES/DRY ANTECEDENT
CONDITIONS ALTHOUGH RIVER LEVELS WILL COME UP SOMEWHAT IN RESPONSE
TO THIS PROLONGED RAIN EVENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WATCH FROM FRIDAY MORNING THROUGH SATURDAY MORNING FOR
LMZ844>849.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT FRIDAY
FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION...UPDATE
NWS JACKSON MS
1035 AM CDT THU AUG 9 2012
.UPDATE...RECIPE FOR LOCALIZED HEAVY RAINFALL IN PLACE THIS MORNING
UP ALONG AND HIGHWAY 82 CORRIDOR IN CENTRAL MISSISSIPPI AS A RATHER
STRONG SUMMER TROUGH DIVES SOUTHEAST INTO THE REGION. WARM AIR AND
MOISTURE ADVECTION EARLIER THIS MORNING KICKED OFF A SLOW MOVING
CLUSTER OF THUNDERSTORMS IN THIS NEIGHBORHOOD THAT HAS SINCE SHOWN A
STRONG TENDENCY TO BACK-BUILD AND TRAIN ACTIVITY OVER SIMILAR AREAS.
THIS TENDENCY IS EXPLAINED WELL BY LATEST RUC ANALYSIS REVEALING 850
MB CORFIDI VECTOR RIDGING JUXTAPOSING ITSELF IN THE SAME GENERAL
REGION. MIX OF MODELS AND ANALYSIS ALSO REVEAL SUBTLE RIGHT ENTRANCE
REGION JET STREAM DYNAMICS COULD ALSO BE IMPARTING ADDITIONAL
ATMOSPHERIC LIFT TO THE SITUATION. BY EARLY AFTERNOON (AND HOPEFULLY
BEFORE) THE ATMOSPHERIC SITUATION PRODUCING THE TRAINING CONVECTION
SHOULD EVOLVE TO THE POINT WHERE ACTIVITY WILL PROGRESS SOUTHEAST
(AND THUS NOT TRAIN AND BE SUCH A FLASH FLOOD WORRY).
OTHERWISE...SHOWERS AND STORMS IN THE FORECAST AREA SO FAR THIS
MORNING HAVE MAINLY BEEN CONFINED TO THE AFOREMENTIONED HIGHWAY 82
CORRIDOR. HOWEVER...THIS SHOULD CHANGE IN THE NEXT FEW HOURS SINCE
THE INCOMING UPPER TROUGH IS IMPARTING MORE AND MORE LIFT ACROSS THE
WHOLE OF THE REGION AND FAVORABLE MOISTURE ADVECTION VECTORS ARE
EVOLVING. BEST CHANCES FOR STORMS WILL OF COURSE BE RIGHT NOW IN
NORTH-CENTRAL AND NORTHEASTERN ZONES (WHERE IT IS RAINING LIKE
HECK)...BUT IN 2 TO 3 HOURS THE BEST CHANCES WILL SHIFT TO AREAS
ROUGHLY ALONG AND SOUTH OF THE NATCHEZ TRACE CORRIDOR THROUGH MID TO
LATE AFTERNOON. FORTUNATELY...WE DO NOT EXPECT A REPEAT OF BIG
FLOODING WORRIES FURTHER SOUTH IN THE REGION TODAY...ALTHOUGH
COMBINATION OF MODEST SHEAR/MODEST INSTABILITY AND AMPLE LIFT WILL
UNDOUBTEDLY BE ENOUGH TO GENERATE SOME STRONG TO OCCASIONAL SEVERE
STORMS. MAIN RISK WITH THE MOST INTENSE STORMS WILL BE DAMAGING
WINDS AND HAIL UP TO QUARTER SIZE OR SO.
BY LATE THIS AFTERNOON WE ANTICIPATE MOST STORMS ASSOCIATED WITH
FIRST SHORT WAVE SHOULD BE EXITING TO THE EAST OR SOUTH OF THE
FORECAST AREA WHILE ANOTHER VIGOROUS SHORT WAVE (ASSOCIATED WITH AN
ACTUAL COLD FRONT) COMES PLOWING TOWARDS THE AREA FROM THE NORTH.
THIS WILL LIKELY BRING ADDITIONAL THUNDERSTORM CHANCES TO AT LEAST
NORTHERN ZONES BY EARLY THIS EVENING (IF NOT A LITTLE
EARLIER)...WITH AGAIN A POTENTIAL FOR SOME SEVERE ACTIVITY TO BE
THROWN IN THE MIX.
EXPECT MORE TO COME WITH THE MAIN AFTERNOON FORECAST PACKAGE...BUT
FOR NOW I HAVE MAINLY ADJUSTED FORECAST SOME TO ACCOUNT FOR LOCALLY
HEAVY RAIN IN NORTHEASTERN ZONES. TO HWO IS ALSO BEING TWEAKED IN
RESPONSE TO THIS RISK. /BB/
&&
.PREV DISCUSSION... /ISSUED 319 AM CDT THU AUG 9 2012/
SHORT TERM...COMPLEX CONVECTIVE FORECAST FOR THIS SHORT TERM AS THE
EVOLVING MEAN LONG WAVE TROUGH WILL CONTAIN MULTIPLE S/WV`S WHICH
WILL DRIVE THE SENSIBLE WEATHER FOR EACH PERIOD. OVERALL...THE
MODELS ARE TRYING TO MAKE SENSE OF IT ALL AND I FEEL GOOD ABOUT WHAT
I HAVE TO WORK WITH GIVEN THE COMPLEXITY OF THE SITUATION.
TO START...THE INITIAL S/WV IS OVER THE W/NW PART OF THE CWA AND IS
CURRENTLY BEGINNING TO GEN UP SOME SHRA/TSRA ACTIVITY ACROSS THAT
AREA. LOOK FOR THIS TO EXPAND IN COVERAGE THROUGH EARLY/MID MORNING
ACROSS THE NW HALF OF THE CWA. AS LIFT FROM THIS FEATURE SHIFTS
E/SE...THE LOW LEVEL RESPONSE AND MOISTURE CONVERGENCE WILL FOLLOW
SUIT. I SEE THE CENTRAL AND SE HALF OF THE AREA GETTING SOMEWHAT OF
AN EARLY START TO THE CONVECTION. BEST PRECIP CHANCES FOR THIS AREA
LOOK TO BE LATE MORNING THROUGH EARLY AFTERNOON. AS THIS
OCCURS...THE NW HALF WILL SEE A BREAK AND HAVE SOME TIME TO WARM UP
AND DESTABILIZE AHEAD OF THE NEXT S/WV (MORE ON THAT IN A BIT). FOR
THE SE HALF AND EASTERN PORTIONS...CONCERNING STRONG/SVR STORM
POTENTIAL. I`M NOT REAL HIGH ON THIS...MAINLY DUE TO THE EARLY START
OF ACTIVITY. HOWEVER...THERE WILL EXIST SOME ENHANCED MID LEVEL FLOW
ASSOCIATED WITH OUR S/WV ALONG WITH SOME MID LEVEL COOLING.
ADDITIONALLY...BETTER THAN AVG FORCING WILL EXIST AS WELL AND I CAN
SEE SOME STRONG STORMS WITH A COUPLE SVR CELLS MIXED IN.
AGAIN...THIS IS FOR THE SE HALF AND EASTERN PORTIONS FROM 11AM
THROUGH 4PM. MAIN RISK LOOKS TO BE FROM 40-60 MPH WINDS AND
LIGHTNING AS STORMS MOVE GENERALLY WEST TO EAST.
SHIFTING TO THE SECOND S/WV AND FOCUSING BACK TOWARD THE NW HALF OF
THE CWA FOR LATE AFTERNOON/EVENING. THIS PORTION OF THE CWA WILL
HAVE THE OPPORTUNITY TO WARM INTO MID 90S. ADDITIONALLY...TEMPS
ALOFT WILL REMAIN COOLER THAN AVG AND PROMOTE FAIRLY STEEP LAPSE
RATES WITH VERTICAL TOTALS AROUND 28C. THIS 2ND S/WV WILL CONTAIN A
STRONGER MID LEVEL SPEED MAX ALONG WITH AN ASSOCIATED MID LEVEL DRY
PUNCH DIVING SE ACROSS THE SOUTHERN PLAINS. IT IS THIS PART OF THE
CWA WHERE I`M MORE CONCERNED WITH SVR STORMS BETWEEN 5 PM AND
MIDNIGHT. ADDITIONAL ACTIVITY LOOKS TO LINGER PAST MIDNIGHT AS
WELL...JUST LIKELY NOT STRONG. HAZARDS FROM THIS ACTIVITY WILL BE 60
MPH WINDS...QUARTER HAIL AND POTENTIALLY MORE INTENSE LIGHTNING. I
WILL CONSTRUCT GRAPHICS TO ILLUSTRATE EACH RISK ALONG WITH
SEGMENTING THE HWO TO FIT THE SITUATION. LASTLY...LOCALLY HEAVY RAIN
WILL BE POSSIBLE WITH ANY STORM.
ON TO FRI...THIS PERIOD IS A CHALLENGE AS WELL...BUT I`M FEELING
MORE CONFIDENT WITH THE MAJORITY OF THE ACTIVITY OCCURRING ACROSS
THE SOUTH HALF. THE MAIN ISSUE WITH THIS PERIOD IS TIMING. ALL
INDICATIONS ARE...ACTIVITY MAY BE AT THE START OF THE FRI
PERIOD...OR GET A QUICK START. FOR NOW...WILL NOT GO WITH SPECIFIC
TIMING ON POPS DUE TO THE UNCERTAINTY. THE BEST DEEP MOISTURE LOOKS
TO BE ALONG AND SOUTH OF I-20 AS THE DRIER MID LEVEL AIR ASSOCIATED
WITH THE S/WV WILL LIKELY BE OVER THE NORTHERN CWA. ALSO...A MORE
PRONOUNCED NW FLOW WILL EXIST AND ANY STORMS SHOULD MOVE OFF TO THE
SE. AS FOR STRONG STORMS FRI...NOT REALLY EXPECTING MUCH AS THE ONLY
THING GOING FOR IT WOULD BE STRONGER OVERALL WINDS ALOFT. LAPSE
RATES WILL BE RATHER TAME AND INSTABILITY WILL BE LIMITED. AT THIS
POINT...I WOULD BE BEST TO NOT MENTION ANY RISK ON FRI AND SEE HOW
THINGS ARE SETUP AFTER WE DEAL WITH THESE FIRST TWO PERIODS. /CME/
LONG TERM...SATURDAY THROUGH NEXT THURSDAY...BEHIND THE PASSAGE OF
FRIDAY/FRIDAY NIGHT`S COLD FRONT...A DRIER AIRMASS WILL FILTER SOUTH
INTO THE REGION FOR THE WEEKEND. WHILE THIS WILL RESULT IN SLIGHTLY
COOLER AFTERNOON AND OVERNIGHT TEMPERATURES...THE BIGGER STORY WILL
BE THE NOTICEABLY...AND MUCH APPRECIATED...LESS HUMID CONDITIONS
FELT ACROSS THE FORECAST AREA AS DEW POINTS DROP FROM THE MID 70S
WE`VE SEEN THROUGH MUCH OF THE SUMMER...DOWN INTO THE LOW AND MIDDLE
60S.
AS FAR AS TEMPERATURES ARE CONCERNED FOR THE WEEKEND...AS STATED
ABOVE THEY`LL BE SLIGHTLY COOLER. I ADJUSTED HIGHS UP A BIT ON
SATURDAY RESULTING IN THEIR RANGING FROM THE MID 80S TO LOWER 90S...
WHICH IS WARMER THAN MOS YET COOLER THAN THE MET GUIDANCE. AFTER
TAKING A LOOK AT LOW LEVEL TEMPS FORECASTED OVER THE AREA DURING
THIS TIME AND COMPARING THEM WITH LOCAL CLIMATOLOGY...THIS UPWARDS
ADJUSTMENT MADE SENSE. HIGHS WILL BE A TAD WARMER ON SUNDAY...BUT
STILL SLIGHTLY COOLER THAN THOSE FROM RECENT DAYS. LOOK FOR LOWS
SATURDAY NIGHT TO FALL INTO THE LOW AND MIDDLE 60S...AND LOWS SUNDAY
NIGHT TO SLIP INTO THE MID 60S AND LOWER 70S.
UNFORTUNATELY...JUST AS QUICK AS THIS DRIER AIR CAME...THE AIRMASS
WILL MODERATE UP THROUGH THE REMAINDER OF THE FORECAST PERIOD. THIS
BASICALLY EQUATES TO A RETURN TO WHAT`S BEEN THE NORM FOR SUMMER
ACROSS THE CWA...HOT AND HUMID CONDITIONS WITH ISOLATED TO
SCATTERED SHOWERS AND STORMS EACH AFTERNOON...LINGERING INTO THE
EARLY EVENING HOURS. MODELS DO INDICATE A WEAK BOUNDARY TRYING TO
SNEAK INTO THE CWA AND MEANDERING ABOUT ACROSS THE FORECAST AREA
THROUGH MID-WEEK. IF THIS PANS OUT...IT COULD ENHANCE RAIN CHANCES
DURING THE LATTER HALF OF THE FORECAST PERIOD...AND COULD RESULT IN
A COMPLEX OR TWO OF SHOWERS AND STORMS TRAVERSING THE REGION UNDER
NORTHWEST FLOW ALOFT. /19/
&&
.AVIATION...GREATEST AVIATION CONCERN IS THE ONGOING MVFR AND IFR
CONDS ACRS KGWO TO KGTR DUE TO TSRA/LOW CIGS. XPCT CONDS TO IMPROVE
BRIEFLY AT KGTR BY 1530Z WITH ADDITIONAL SCT TSRA THROUGH LATE MRNG
THRU AFTN. FOR CNTRL AND SRN TAF SITES...IT WILL BE MORE TRICKY AS
FAR AS TIMING. SCT TSRA XPCTED TO DVLP ACROSS REGION LATE MRNG AND
PERSIST THROUGH EVENING AS MID LVL DISTURBANCE MOVES THROUGH. CNTRL
AND SRN SITES SHOULD HAVE VFR PREVAIL BUT INTERMITTENT MVFR/IFR
CONDS PSBL THIS AFTN. LOW CIGS/BR OVRNGT SHOULD RESULT IN MIX OF
MVFR/VFR. SLY SFC WINDS WILL BE 6-12 KT WITH SOME HIGHER GUSTS THIS
AFTN. SOME GUSTS TO 20-30 KT PSBL INVOF STRONGER TSRA. STORM TOPS TO
FL450.
/ALLEN/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 92 74 91 69 / 57 42 41 18
MERIDIAN 91 72 92 68 / 58 41 52 30
VICKSBURG 93 74 91 66 / 49 39 34 15
HATTIESBURG 92 75 93 73 / 71 20 54 28
NATCHEZ 91 75 91 70 / 61 29 42 17
GREENVILLE 95 75 91 66 / 38 48 20 9
GREENWOOD 94 74 90 65 / 66 45 22 10
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
BB/ALLEN/CME/19
AREA FORECAST DISCUSSION
NWS BILLINGS MT
918 AM MDT THU AUG 9 2012
.SHORT TERM...VALID FOR TDY AND FRI...
MINOR UPDATE TO THE FORECAST THIS MORNING TO ADD ISOLATED POPS
FROM BAKER SOUTHWEST TO SHERIDAN. WEAK UPPER WAVE WAS DRAGGING A
SURFACE TROUGH ACROSS THIS AREA AND IS GENERATING ISOLATED
PRECIPITATION. A FEW LIGHTNING STRIKES HAVE BEEN OBSERVERED JUST
NORTH OF WHEATLAND COUNTY AS WEAK INSTABILITY IS DEVELOPING.
INCREASED CLOUD COVERAGE OVER THE EASTERN ZONES THIS MORNING BUT
SKY`S SHOULD CLEAR BY EARLY THIS AFTERNOON BEHIND THE UPPER WAVE.
RICHMOND
PREVIOUS DISCUSSION...
EARLY MORNING RAP MODEL DATA AND WATER VAPOR IMAGERY SHOWS THE
UPPER LEVEL RIDGE IS SLOWLY STARTING TO BREAK DOWN ALREADY. EVEN
THOUGH THE RIDGE WILL BECOME FLATTER TODAY...CONDITIONS WILL STILL
BE HOT AND DRY ACROSS THE REGION. THERE IS A SLIGHT CHANCE FOR AN
ISOLATED SHOWER OR THUNDERSTORM...MAINLY OVER WESTERN ZONES...AS
AN IMPULSE OF ENERGY MAKES IT OVER THE AREA THIS AFTERNOON. THERE
IS A LITTLE INSTABILITY OVER MOUNTAINOUS REGIONS IN THE WESTERN
ZONES...BUT NOT SURE IF IT WILL BE REALIZED DUE TO STRONG CAP AT
850 AND 700 MB.
FOR FRIDAY...THE FOCUS TURNS TO THE POTENTIAL FOR WIDESPREAD
SHOWERS AND THUNDERSTORMS OVER MOST OF THE AREA. MODELS ARE
IN GOOD AGREEMENT IN PROGGING A SERIES OF VORTICITY POCKETS OVER
SOUTH CENTRAL MONTANA BY FRIDAY AFTERNOON. THE TIMING IS SLIGHTLY
DIFFERENT BETWEEN THE NAM AND GFS SOLUTIONS...WITH THE GFS
LINGERING A LITTLE BIT LONGER BEFORE EXITING THE CWA TO THE EAST.
500 TO 300 MB Q VECTOR MODEL FIELDS SHOW MAXIMIUM CONVERGENCE
JUST NORTH OF THE CWA...WHICH WILL HELP TO DEVELOP A LEE SIDE
TROUGH AT THE SURFACE. ..AND WILL SERVE AS THE FOCUS FOR MOST OF
THE PRECIPITATION ACTIVITY. MIN ADDITION...A WIND SPEED MAXIMA AT
850 WILL ATTEMPT TO SUPPLY MOISTURE TO THE AREA. THE MAIN MOISTURE
AXIS IS IN WESTERN SOUTH DAKOTA...BUT THE BREADTH OF THE LOW LEVEL
JET SHOULD BE WIDE ENOUGH TO HELP SUPPORT THUNDERSTORM GROWTH OVER
EASTERN ZONES BY FRIDAY NIGHT.
AS FAR AS INSTABILITY IS CONCERNED...LIFTED INDICES APPROACH -5 C
OVER SOUTHEAST MONTANA...WHICH COINCIDES WITH CAPE VALUES
APPROACHING 1000 J/KG AT MODEL SOUNDINGS FOR KBHK. AT CURRENT TIME
SHEAR PROFILES DO NOT APPEAR STRONG ENOUGH TO SUPPORT WIDESPREAD
SEVERE STORMS...BUT THAT MAY CHANGE AS THE SURFACE TROUGH SETS UP.
MAIN CONCERNS WOULD BE FOR LARGE HAIL AND STRONG WINDS. SINGER
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MODELS TRENDING A BIT SLOWER WITH DEPARTURE OF SECONDARY
SHORTWAVE ON SATURDAY...THUS LOOKS LIKE A BETTER CHANCE OF SHOWERS
AND THUNDERSTORMS ESPECIALLY IN OUR EAST ON THIS DAY. WITH
PRECIPITABLE WATERS ON THE ORDER OF 1.2 INCHES AND LOW LCL HEIGHTS
FROM KMLS-K4BQ EASTWARD THINK SOME HEAVY RAIN IS A POSSIBILITY.
THIS ENERGY WILL EXIT TO THE EAST BY SATURDAY EVENING. HAVE
TAPERED BACK EXPECTED HIGHS A BIT IN OUR EAST.
CHANCES OF PCPN NOT GREAT IN THE SUNDAY-TUESDAY TIME PERIOD AS
UPPER LEVEL RIDGE AND HIGH HEIGHTS WILL BE DOMINANT...BUT COULD BE
SOME MAINLY DIURNAL WEAK CONVECTION OVER OUR MTNS AND PERHAPS AT
TIMES IN OUR EAST WHERE LOW LEVEL BOUNDARY AND EAST WINDS WILL
LINGER. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH HIGHS MOSTLY
IN THE UPPER 80S TO MID 90S. TUESDAY MAY BE THE WARMEST DAY GIVEN
POTENTIAL FOR PREFRONTAL WARMING UNDER INCREASED SW FLOW ALOFT.
MODELS IN GOOD OVERALL AGREEMENT IN SHOWING A COOL DOWN BY
WEDNESDAY AND THURSDAY OF NEXT WEEK...THOUGH WITH DIFFERENCES IN
THE DETAILS AS SHARP UPPER TROF SLIDES OUT OF THE NORTHWEST. MODEL
CONSENSUS SUGGESTS COOL ADVECTION AND NORTH WINDS BEGINNING
WEDNESDAY AND A MUCH COOLER DAY BY THURSDAY...WITH INCREASED
CHANCES OF PRECIPITATION. WITH SOME CONFIDENCE HAVE RAISED POPS TO
ABOVE CLIMATOLOGY...AND EXPECT TEMPS TO FALL BELOW NORMAL BY
THURSDAY.
JKL
&&
.AVIATION...
MOSTLY CLOUDY SKIES WILL GIVE WAY TO PARTLY CLOUDY SKIES EAST OF
A KSHR-KMLS LINE TODAY. WEST OF THIS LINE...EXPECT PARTLY TO
MOSTLY SUNNY SKIES. AN ISOLATED THUNDERSTORM WILL BE
POSSIBLE...MAINLY OVER THE MOUNTAINS AND ADJACENT FOOTHILLS. GUSTY
ERRATIC WINDS AND MVFR CONDITIONS WILL BE POSSIBLE WITH ANY
THUNDERSTORM. WIDESPREAD AREAS OF SMOKE WILL EXIST AS WELL...BUT
OVERALL...VFR CONDITIONS WILL PREVAIL TODAY. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 098 062/091 063/088 061/093 062/093 063/091 060/083
2/T 23/T 42/T 11/B 21/B 11/B 22/T
LVM 096 054/088 055/090 052/093 052/092 053/087 051/083
3/T 34/T 41/B 11/B 21/B 12/T 23/T
HDN 101 063/094 063/091 061/095 061/096 063/094 058/085
2/T 23/T 42/T 11/U 21/B 11/B 22/T
MLS 099 065/093 066/088 062/093 064/095 064/092 062/086
2/T 23/T 43/T 12/T 22/T 11/B 22/T
4BQ 098 064/092 064/088 061/093 062/094 065/093 060/087
2/T 23/T 53/T 11/U 12/T 11/B 22/T
BHK 092 062/089 063/084 060/088 061/090 064/090 061/085
2/T 23/T 54/T 22/T 22/T 22/T 22/T
SHR 097 059/090 060/087 056/091 058/094 059/093 055/086
2/T 23/T 42/T 11/B 12/T 11/B 22/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EDT THU AUG 9 2012
.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA TODAY. A STRONG
SURFACE COLD FRONT WILL APPROACH OUR REGION FROM THE NORTHWEST
FRIDAY AND CROSS CENTRAL NC ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM THURSDAY...
A SMALL AREA OF STRATUS OVER WILSON...NASH AND EDGECOMBE COUNTIES IS
ERODING AND DRIFTING NORTHEAST AND WILL GIVE WAY TO MOSTLY CLEAR
SKIES OVER THE COASTAL PLAIN THIS MORNING. HOWEVER...SOME THIN HIGH
CLOUDS OUT AHEAD OF CONVECTION OVER NORTHERN MS/AL WILL OVERSPREAD
THE AREA FROM THE WEST...AND SHOULD BECOME THICKER OVER THE WESTERN
PIEDMONT LATER TODAY AS THE SHORTWAVE RESPONSIBLE FOR THE CONVECTION
SWINGS INTO THE SOUTHEAST US. TEMPS WILL BE MOSTLY UNAFFECTED BY
THE CLOUDS...HOWEVER. THE 12Z KGSO RAOB CAME IN WITH A LOW LEVEL
THICKNESS OF 1414M... A GOOD 5M HIGHER THAN FORECAST. ADDING A
COUPLE DEGREES ONTO HIGHS DERIVED FROM 1414M YIELDS 90-93...WHICH IS
IN LINE WITH STATISTICAL GUIDANCE AND THE CURRENT FORECAST.
MODIFIED 12Z RAOBS AND MODEL FORECASTS SHOW 1500-2000 J/KG OF MLCAPE
THIS AFTERNOON...GREATEST FROM THE COASTAL PLAIN TO THE SOUTHERN
PIEDMONT. WEAK LOW LEVEL FORCING...ALONG WITH MUCH DRIER MID LEVEL
AIR THAN THE PAST FEW DAYS...SHOULD LIMIT COVERAGE OF CONVECTION TO
MOSTLY ISOLATED STORMS. THERE IS A SMALL HINT OF A WEAK SURFACE
OVER THE WESTERN PIEDMONT...AND THE MORNING RUNS OF THE HRRR HAS
BEEN CONSISTENTLY SHOWING CONVECTION INVITATION FROM ANSON COUNTY TO
RANDOLPH COUNTY JUST AFTER 18Z. ANY STRONGER STORMS THAT DEVELOP
WILL HAVE PLENTY OF DRY AIR TO ENTRAIN...AS WELL AS A WETBULB
FREEZING LEVEL BELOW 10K FT...SO AN ISOLATED WIND/HAIL THREAT WILL
EXIST. -SMITH
TONIGHT...DECENT MID LEVEL TROUGH CURRENTLY OVER THE MO/ARK OZARKS
PROJECTED TO ADVANCE EWD AND WILL APPROACH OUR REGION AFTER SUNSET.
THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS FEATURE AND
CONFIDENCE INCREASING THAT WE WILL LIKELY SEE AT LEAST SCATTERED
CONVECTION EITHER MOVE INTO OR DEVELOPMENT OVER THE WESTERN PIEDMONT
AFTER MIDNIGHT. HAVE INCREASED POPS SLIGHTLY IN THE FAR WEST TO 40
PERCENT. IF MODEL GUIDANCE REMAINS CONSISTENT....COULD ARGUE FOR A
MENTION OF LIKELY THOUGH LOW LEVEL ATMOSPHERE WILL ACHIEVE MAXIMUM
STABILITY DURING THIS PERIOD. MIN TEMPS UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 315 AM THURSDAY...
FRIDAY...CONVECTIVELY ACTIVE DAY POSSIBLE ACROSS CENTRAL NC THOUGH
STILL SOME QUESTION AS THE AMOUNT OF INSTABILITY AND SHEAR THAT WILL
BE ATTAINED.
AFOREMENTIONED MID LEVEL TROUGH WILL SLOW ITS EWD ADVANCE...WAITING
FOR ENERGY ROTATING AROUND THE DEEPENING UPPER LEVEL TROUGH OVER THE
GREAT LAKES TO ROUND THE BASE OF THE TROUGH. THIS LEAD TROUGH WILL
LIKELY MAINTAIN CONSIDERABLE CLOUDINESS IN THE MORNING ALONG WITH
SCATTERED TO NUMEROUS SHOWERS AND A FEW T-STORMS. AS THE ENERGY IN
THE GREAT LAKES TROUGH GETS CLOSER TO THE APPALACHIANS AND MID
ATLANTIC...SHOULD SEE AN INCREASE IN THE 850-700MB WIND FIELD
LEADING TO BETTER BULK SHEAR (AROUND 30 KTS) SUGGESTING BETTER
POTENTIAL FOR ORGANIZED CONVECTION. DUE TO DEEP UNIDIRECTIONAL
FLOW...EXPECT MAINLY MULTICELLULAR LINEAR CONVECTION WITH POTENTIAL
FOR DAMAGING WIND GUSTS AND SOME HAIL. TIMING FAVORS LATE FRIDAY
INTO FRIDAY EVENING...AND MAINLY ALONG AND EAST OF HIGHWAY 1 WHERE
BETTER LOW LEVEL INSTABILITY WILL LIE.
TEMPS FRIDAY DEPENDENT ON AMOUNT OF INSOLATION. EXPECT A PERIOD OF
PARTIAL SUN IN THE AFTERNOON PRIOR TO CONVECTION BECOMING MORE
ACTIVE. THICKNESSES IN THE LOWER 1420S SUPPORT MAX TEMPS IN THE 80S
TO NEAR 90.
FRIDAY NIGHT...EXPECT ACTIVE CONVECTION TO PERSIST THROUGH THE NIGHT
AS TROUGH BECOMES ELONGATED DUE TO APPROACH OF GREAT LAKES SYSTEM.
DEEPENING SW FLOW WILL LIKELY CAUSE CONVECTIVE BANDS TO TRAIN NEWD.
THUS...SHOULD SEE WEATHER SCENARIO TRANSITION FROM A SEVERE WEATHER
THREAT IN THE EARLY EVENING TO A HEAVY RAIN THREAT THAT WILL PERSIST
INTO EARLY SATURDAY. WILL CONTINUE LIKELY POPS FOR NOW. MIN TEMPS
UPPER 60S TO LOWER 70S. -WSS
SATURDAY AND SATURDAY NIGHT:
THE SURFACE COLD FRONT IS EXPECTED TO SLOWLY MOVE ACROSS CENTRAL NC
ON SATURDAY... BEFORE STALLING AND DISSIPATING ACROSS THE COASTAL
PLAIN OR JUST TO THE SOUTH AND EAST OF THE AREA SATURDAY NIGHT INTO
SUNDAY. HAVE FOLLOWED CLOSER TO A BLEND OF THE GFS AND ECWMF WRT THE
FRONTAL TIMING AS HPC CONTINUES TO NOTE THE NAM APPEARS TO BE A SLOW
OUTLIER. THIS WILL LEAD TO ANOTHER GOOD CHANCE OF SHOWERS AND STORMS
FOR AT LEAST EASTERN AND SOUTH/SOUTHEASTERN PORTIONS OF THE AREA.
HAVE INCREASED POPS ACROSS THE EASTERN AND SOUTH/SOUTHEASTERN
PORTIONS OF THE AREA FOR SATURDAY... GIVEN A BIT SLOWER TIMING OF
THE FRONT. THIS YIELDS LIKELY POPS EAST/SOUTHEAST TO SLIGHT CHANCE
NORTHWEST. WITH THE SURFACE FRONT DRAPED ACROSS THE AREA A GOOD PART
OF THE DAY THIS WILL CREATE A TRICKY HIGH TEMP FORECAST ALONG WITH
HOW MUCH INSTABILITY WILL BE PRESENT (HOW MUCH HEATING WILL WE BE
ABLE TO REALIZE WITH THE PARTLY SUNNY TO MOSTLY CLOUDY SKIES) AND
RESULTANT SEVERE STORM CHANCES. THE GFS IS SHOWING 1000 TO 1500 J/KG
OF MLCAPE FOR SATURDAY AFTERNOON GENERALLY ALONG AND EAST OF U.S.
HIGHWAY 1. THIS COMBINED WITH CONTINUED LARGE SCALE LIFT AND DEEP
LAYER SHEAR ON THE ORDER OF 30 TO 35 KTS SHOULD LEAD TO AT LEAST
SOME ORGANIZED CONVECTION ACROSS EASTERN PORTIONS OF THE AREA...
WITH THE MAIN SEVERE THREAT FROM DAMAGING WINDS. IN ADDITION TO THE
THREAT FOR SEVERE STORMS... THE STRONGEST STORMS WILL LIKELY PRODUCE
HEAVY RAIN AS PW`S ARE EXPECTED TO CONTINUE TO BE AROUND 2 INCHES
ACROSS THE EAST AND SOUTH/SOUTHEAST. THIS MAY LEAD TO A FLASH
FLOODING THREAT WITH THE POTENTIAL OF THE SLOW MOVING FRONT...
ESPECIALLY ACROSS URBAN AREAS. WILL ADD MENTION OF SEVERE STORMS AND
FLASH FLOODING TO THE HWO FOR THIS TIMEFRAME.
WILL TREND POPS DOWNWARD SATURDAY NIGHT AS THE CLOSED LOW ALOFT OVER
THE GREAT LAKES BEGINS TO LIFT NORTH-NORTHEASTWARD ALLOWING THE MAIN
MID LEVEL TROUGH AXIS TO SWING THROUGH THE AREA. THIS WILL YIELD NO
POPS NW TO SLIGHT CHANCE/CHANCE EAST/SOUTHEAST. AS MENTIONED
ABOVE... HIGH TEMPS WILL BE TRICKY FOR SATURDAY. FOR NOW WILL KEEP
HIGHS IN THE MID TO UPPER 80S ACROSS THE AREA. LOW TEMPS ON SUNDAY
MORNING ARE EXPECTED TO RANGE FROM THE MID 60S NW TO AROUND 70 SE.
-BSD
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 315 AM THURSDAY...
THE COLD FRONT MENTIONED IN THE SHORT TERM DISCUSSION ABOVE IS
EXPECTED TO CONTINUE TO DISSIPATE/WASH OUT ON SUNDAY JUST TO THE
EAST AND SOUTHEAST OF THE AREA AS THE MID/UPPER FLOW BECOMES MORE
ZONAL IN THE WAKE OF THE DEPARTED MID/UPPER TROUGH ALOFT. THIS WILL
RESULTED IN GENERALLY DRY CONDITIONS... WITH ONLY SLIGHT CHANCES FOR
SHOWERS AND STORMS ON SUNDAY AND MONDAY. UNCERTAINTY GROWS WRT THE
STRENGTH AND TIMING OF A MUCH WEAKER S/W TROUGH ALOFT AND MOISTURE
RETURN FOR MONDAY NIGHT THROUGH TUESDAY NIGHT. FOR NOW WILL SHOW A
SLIGHT CHANCE OF DIURNAL SHOWERS AND STORMS FOR THIS TIMEFRAME. THE
WEAK S/W TROUGH ALOFT IS EXPECTED TO BE EAST OF THE AREA BY
WEDNESDAY WITH RIDING ALOFT BUILDING BACK INTO THE AREA... YIELDING
LESS OF A CHANCE OF AFTERNOON AND EVENING STORMS. TEMPS DURING THE
PERIOD ARE EXPECTED TO BE IN THE MID TO UPPER 80S... WITH PERHAPS A
RETURN TO SOME LOCATIONS REACHING THE LOWER 90S AGAIN BY EARLY TO
MID NEXT WEEK.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 730 AM THURSDAY...
POCKETS OF LIFR/LIFR VISIBILITY AND CEILINGS EARLY THIS MORNING WILL
DISSIPATE PRIOR TO 9 AM...LEAVING SCATTERED CLOUDS WITH BASES
1500-3000FT. BY EARLY AFTERNOON...SCATTERED CUMULUS WILL PREVAIL
WITH BASES 4000-5000FT.
AFTERNOON CONVECTION SHOULD BE LIMITED AS THERE IS A LACK OF A
TRIGGER ALOFT AND NEAR THE SURFACE. THUS ONLY EXPECT ISOLATED
CONVECTION THIS AFTERNOON THROUGH THE EARLY EVENING HOURS.
A MID LEVEL TROUGH WILL APPROACH CENTRAL NC LATE TONIGHT. THIS
WEATHER SYSTEM WILL TRIGGER A FEW SHOWERS AND ISOLATED T-STORMS LATE
TONIGHT (AFTER 10-11 PM) OVER THE WESTERN AND SOUTHERN PIEDMONT
INCLUDING IN VICINITY OF THE TRIAD TERMINALS. LATER FRIDAY AND
FRIDAY...AN UPPER LEVEL TROUGH AND ATTENDANT SURFACE COLD FRONT WILL
APPROACH FROM THE WEST. THIS SYSTEM INTERACTING WITH THE MOIST
UNSTABLE AIR IN PLACE WILL TRIGGER/SUSTAIN SCATTERED-NUMEROUS
SHOWERS AND T-STORMS FRIDAY AFTERNOON AND FRIDAY NIGHT. THIS WILL
CAUSE PERIODS OF SUB VFR CONDITIONS AT ALL TAF SITES. THE STRONGER
CELLS WILL HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND GUSTS IN
EXCESS OF 50KTS.
BY SATURDAY...CONDITIONS WILL BE IMPROVING IN THE NW PIEDMONT BUT
STILL EXPECT A DECENT THREAT FOR SCATTERED CONVECTION OVER THE
REMAINDER OF CENTRAL NC WITH EPISODES OF SUB-VFR CEILING AND
VISIBILITY DUE TO THE SHOWERS AND T-STORMS.
THE SURFACE COLD FRONT SHOULD EDGE EAST OUT OF OUR AREA SATURDAY
NIGHT INTO SUNDAY MORNING WITH IMPROVING AVIATION CONDITIONS
PROJECTED TO LAST THROUGH MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS/BSD
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
711 AM CDT THU AUG 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY
241 AM CDT THU AUG 9 2012
MAIN CONCERNS INCLUDE RAIN CHANCES TODAY INTO THIS EVENING/FOG FRIDAY
NIGHT/TEMPERATURES THROUGH THE PERIOD.
LATEST WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWING A MID-LEVEL
SHORTWAVE TROUGH MOVING SOUTHEAST ACROSS SOUTHERN WI/EASTERN IA.
ANOTHER MORE VIGOROUS SHORTWAVE WAS MOVING SOUTH THROUGH WESTERN
ONTARIO/ARROWHEAD REGION OF MN. SOUTHERN SHORTWAVE TROUGH
DEFORMATION AREA WAS PRODUCING SOME 700MB FRONTOGENETIC FORCING AND
RESULTING IN SCATTERED -SHRA ACTIVITY MAINLY EAST OF THE MISSISSIPPI
RIVER. RAP SHOWS THIS FRONTOGENESIS WEAKENING OVER THE NEXT FEW
HOURS...AND RADAR MOSAIC ALREADY SHOWING DISSIPATION OF THE SHRA
ACTIVITY. MEANWHILE...THE TROUGH DROPPING SOUTH THROUGH
ONTARIO/NORTHERN MN WAS PRODUCING A MORE ORGANIZED BAND OF
SHRA/ISOLD THUNDER IN GOOD 700-300MB PV-ADVECTION PER THE RAP.
OTHERWISE...SKIES ACROSS THE AREA WERE MOSTLY CLOUDY WITH
TEMPERATURES IN THE 60S.
LATEST NCEP MODELS/SREF REMAIN IN GOOD AGREEMENT THROUGH THE SHORT
TERM PERIOD.
FOR TODAY...WILL BE WATCHING THE WAVE OVER ONTARIO/NORTHERN MN DROP
SOUTHEAST ACROSS THE AREA. INCREASING PV-ADVECTION/STEEPENING LAPSE
RATES ACROSS THE AREA WILL LEAD TO MORE SHOWER/THUNDER DEVELOPMENT.
BEST FORCING APPEARS TO BE EAST OF THE MISSISSIPPI...SO TRENDED POPS
HIGHER THERE. IN ADDITION...THE NAM INDICATING 0-3KM MUCAPE
INCREASING INTO THE 1000-1500J/KG RANGE BY NOON WITH BULK SHEAR IN THE
15 TO 30KT RANGE FOR PERHAPS SOME LINEAR ORGANIZATION OF THE
CONVECTION. WITH THIS IN MIND...ALONG WITH COLDER AIR ALOFT AND
LOWERING WET BULB ZERO HEIGHTS...WILL HAVE TO WATCH FOR ISOLATED
SEVERE THREAT TODAY WITH HAIL AND WIND BEING THE MAIN THREATS.
OTHERWISE...TEMPERATURES WILL BE A BIT COOLER WITH THE
TROUGH/SCATTERED CONVECTION. ANTICIPATING HIGHS TODAY RANGING FROM
THE UPPER 60S ACROSS NORTH CENTRAL WI...TO THE LOWER/MID 70S
ELSEWHERE.
LOOK FOR THE TROUGH TO DEEPEN/FORM A CLOSED LOW AS IT MOVES
SOUTHEAST OF THE AREA TONIGHT TOWARD IN/MI BORDER BY FRI 12Z. AT THE
SURFACE...HIGH PRESSURE WILL BE BUILDING INTO THE AREA WITH
DRYING/NORTHERLY FLOW. THIS IS EXPECTED TO DRY UP/PUSH ANY LINGERING
SHRA ACTIVITY SOUTHEAST OF THE AREA BY MIDNIGHT...WITH CLEARING
SKIES FROM NORTHWEST TO SOUTHEAST. LOOK FOR LOWS IN THE LOWER/MID
50S WITH POCKETS OF MID/UPPER 40S IN THE CRANBERRY BOG AREAS OF
CENTRAL WI.
ON FRIDAY...CLOSED MID-LEVEL AND DEEP SURFACE LOW WILL HANG UP OVER
SOUTHERN LOWER MI AS HIGH PRESSURE CONTINUES TO BUILD INTO OUR AREA.
DECENT DRYING NORTHERLY FLOW WILL RESULT ACROSS THE AREA. MAY SEE
SOME CUMULUS BUILD UP ACROSS THE EASTERN PORTION OF THE AREA DUE TO
CLOSER PROXIMITY OF COLDER/CYCLONIC FLOW ALOFT. TRENDED DEW POINTS
LOWER DUE TO ANTICIPATED DEEPER MIXING TO 825MB PER THE NAM BUFKIT
SOUNDING. HIGH TEMPERATURES WILL CONTINUE TO BE A BIT ON THE COOLER
THAN NORMAL SIDE IN THE 70S.
HIGH PRESSURE WILL SETTLE OVERHEAD FRIDAY NIGHT WITH THE RIDGE AXIS
OVER AT LEAST THE WESTERN HALF OF THE FORECAST AREA. LIGHT
WINDS/CLEAR SKIES AND WATER TEMPERATURES SITTING IN THE UPPER 70S
WILL LIKELY LEAD TO SOME RIVER VALLEY FOG TOWARD MORNING.
OTHERWISE...OVERNIGHT LOWS WILL BE QUITE COOL IN THE 40S. HIGH
PRESSURE CONTINUES TO BE IN CONTROL ACROSS THE AREA THROUGH SATURDAY
FOR DRY CONDITION WITH HIGHS IN THE MID/UPPER 70S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
241 AM CDT THU AUG 9 2012
LATEST GFS/ECMWF I FAIRLY DECENT AGREEMENT THROUGH THE EXTENDED
FORECAST PERIOD. BOTH SHOW A WEAK MID-LEVEL TROUGH MOVING EAST OUT
OF THE DAKOTAS/CENTRAL PLAINS TOWARD THE AREA SATURDAY NIGHT THROUGH
SUNDAY NIGHT FOR A SMALL CHANCE OF SHOWER/THUNDERSTORMS. A MORE
SIGNIFICANT LOW PRESSURE SYSTEM IS SLATED TO MOVE EAST OUT OF THE
PACIFIC NORTHWEST INTO THE REGION BY WEDNESDAY. WARM AIR ADVECTION
IN ADVANCE OF THIS SYSTEM WILL GIVE THE AREA INCREASING
SHOWER/THUNDERSTORM CHANCES FROM TUESDAY INTO WEDNESDAY.
OTHERWISE...LOOK FOR TEMPERATURES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL IN THE EXTENDED WITH HIGHS WARMING FROM THE 70S ON SUNDAY TO
WELL INTO THE 80S TUESDAY AND WEDNESDAY.
&&
.AVIATION...TODAY AND TONIGHT
711 AM CDT THU AUG 9 2012
INVERTED TROUGH EXTENDING NORTH FROM THE SURFACE LOW OVER MO/IL
REACHES UP RIGHT ALONG THE MISSISSIPPI NEAR KLSE. MOISTURE POOLING
NEAR THE BOUNDARY HELPING TO FUEL LOW STRATUS ACROSS NORTHERN
IA...SOUTHEAST MN...AND WESTERN/NORTHERN WI. KRST OBSERVATIONS
HAVE RECENTLY GONE DOWN TO LIFR AND ANTICIPATE THIS TO LINGER FOR
A FEW HOURS THIS MORNING. SLOW IMPROVEMENT TO MVFR BY 16Z IS
ANTICIPATED. KLSE IS A BIT CLOSER TO THE WIND SHIFT AND THUS THE
LOWEST CLOUD IS NOT IMPACTING THE AIRPORT DIRECTLY. MVFR
CONDITIONS SHOULD PREVAIL...BUT PERIODS OF IFR/LIFR POSSIBLE FOR A
FEW HOURS THIS MORNING.
UPPER LEVEL SHORT WAVE TROUGH APPROACHING THUNDER BAY THIS MORNING
WILL DROP SOUTHEAST INTO THE GREAT LAKES BY TONIGHT. ASSOCIATED
SURFACE LOW AND COLD FRONT ARE EXPECTED TO SWEEP THROUGH THE
REGION AS WELL. THIS SHOULD BRING ANOTHER RISK FOR SHRA THIS
AFTERNOON. BEST FORCING APPEARS TO BE EAST OF THE MISSISSIPPI SO
DO NOT ANTICIPATE A LARGE THREAT FOR THUNDER AT KLSE. THUS HAVE
LEFT IT OUT OF THE TAF AT THIS TIME.
FINAL CONCERN IS FOR FOG TONIGHT AS THE SYSTEM DEPARTS THE AREA
AND HIGH PRESSURE BUILDS IN. RIDGE AXIS WILL NOT MAKE IT
COMPLETELY INTO THE AREA...SO WINDS MAY STAY UP JUST ENOUGH TO
KEEP THE DENSE FOG TO FORM. BUT I DO ANTICIPATE AT LEAST SOME
LIGHT FOG/MIST TO DEVELOP...SO ADDED TO THE TAFS. LATER SHIFTS
WILL MONITOR THE CLEARING TREND THIS EVENING...AND PROGRESS OF THE
RIDGE AXIS TONIGHT...TO DETERMINE IF CHANGES TO THE FOG FORECAST
ARE NEEDED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
241 AM CDT THU AUG 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...MW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
542 PM EDT THU AUG 9 2012
.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT APPROACH TONIGHT THROUGH FRIDAY. A
SECONDARY LOW WILL FORM AND IMPACT THE AREA FRIDAY NIGHT THROUGH
SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS A PRE-FRONTAL TROUGH EDGES CLOSER TO WESTERN PORTIONS OF THE
CWA...SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND TRACK
EAST. ML MUCAPE VALUES REMAIN QUITE HIGH...AVERAGING 2000-3000
J/KG OVER THE AREA...BUT MOST OF THE MODELS HAVE THE STORMS BARELY
MAKING IT THROUGH NYC BEFORE ENDING JUST AS THEY APPROACH
FAIRFIELD AND NASSAU COUNTIES. ONLY THE HRRR MODEL HAS STORMS
GOING THROUGH NYC AND INTO WESTERN CT AND LONG ISLAND.
STORMS THE DEVELOPED ALONG THE NORTH SHORE OF LONG ISLAND IN
ASSOCIATION WITH THE SEA BREEZE BOUNDARY HAVE ENDED...AND DO NOT
THINK MUCH ADDITIONAL ACTIVITY WILL OCCUR FROM THAT BOUNDARY.
WILL FOLLOW THE GUIDANCE AND KEEP LIKELY POPS CONFINED TO FAR NW
ZONES...MAINLY ORANGE/ROCKLAND AND WESTERN PASSAIC COUNTIES...AND
HIGH CHANCE ALONG AND WEST OF THE HUDSON RIVER. ONCE STORMS FIRE
UP AND TRACK EAST...THEY WILL MOVE INTO AN ATMOSPHERE THAT REMAINS
UNSTABLE. MID-LEVEL STEERING CURRENT SEEMS LOW...SO STORMS WILL
TRACK FAIRLY SLOWLY. THIS WILL RESULT IN AREAS OF LOCALLY HEAVY
RAINFALL...WHICH COULD RESULT IN FLASH FLOODING. AT THE VERY
LEAST...URBAN/POOR DRAINAGE/SMALL STREAM FLOODING CAN BE EXPECTED.
IN ADDITION...STORMS ARE CAPABLE OF GUSTY WINDS AND FREQUENT AND
DANGEROUS LIGHTNING STRIKES.
STORMS TAPER OFF BY MIDNIGHT. LOW PRES OVER THE MIDWEST CONTINUES
TO MOVE INTO THE OH VALLEY...SO WILL KEEP AT LEAST SLIGHT CHANCE
TO LOW CHANCE POPS IN THE FORECAST THROUGH THE OVERNIGHT. WITH
ABUNDANT LOW LEVEL MOISTURE IN THE ATMOSPHERE...EXPECTING LOW
STRATUS/FOG TO DEVELOP AFTER MIDNIGHT.
WARM AND HUMID TONIGHT WITH LOWS IN THE MID 70S IN/AROUND NYC AND
IN THE UPPER 60S ELSEWHERE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
LOW PRES OVER THE GREAT LAKES MOVES INTO THE OH VALLEY FRIDAY
AFTERNOON AND INTENSIFIES AS IT THEN TRACKS OVER LAKE HURON. THIS
SYSTEM WILL PUSH A WARM FRONT ALONG THE EAST COAST AND THROUGH THE
REGION FROM SOUTH TO NORTH DURING THE DAY FRIDAY. AS THIS FRONT
TRACKS NORTH...IT WILL HAVE UPPER LEVEL SUPPORT FROM A MID LEVEL
SHORTWAVE TRACKING ALONG THE COAST. SHOWERS AND THUNDERSTORMS WILL
OVERSPREAD THE REGION FROM SOUTH TO NORTH...AND WITH ELEVATED
INSTABILITY OVER THE REGION...GUSTY WINDS AND FREQUENT LIGHTNING
CAN BE EXPECTED. A TROPICAL AIRMASS WILL OVERSPREAD THE REGION...
MAKING IT VERY WARM AND HUMID. WITH PWATS APPROACHING 2"...HEAVY
RAIN AND FLASH FLOODING IS POSSIBLE.
AS THE LOW INTENSIFIES OVER LAKE HURON LATE FRIDAY...A SECONDARY
LOW WILL FORM OVER THE DELMARVA...TRACK ALONG THE COAST...AND MOVE
INTO THE LOCAL AREA LATE FRIDAY THROUGH FRIDAY NIGHT. HEAVY RAIN
AND GUSTY WINDS ALONG WITH POSSIBLE FLASH FLOODING EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
SURFACE LOW OVER SOUTHERN ONTARIO SATURDAY AM BEINGS ITS GRADUALLY
FILLING PROCESS AS THE COLD FRONT FINALLY REACHES THE NYC METRO
AREA. THE INSTABILITY IS RATHER LIMITED AND HAVE FOCUSED MAINLY ON
THE PASSING NATURE OF SHOWERS AND CALLED IT ONLY ISOLATED FOR THE
THUNDERSTORM CHANCE. MAIN FOCUS FOR HEAVIER RAINFALL WOULD BE
EAST OF THE HUDSON - LONG ISLAND AND CT WITH RAINING SHOWERS. IN
ADDITION...THE BEST LIKELIHOOD OF SHOWERS WOULD BE THE MORNING.
IN TERMS OF MODELS...GOOD AGREEMENT IN THE DETERMINISTIC 12Z
RUNS...BUT 15Z SERF IS SUPPORTING A SLOWER PASSAGE OF THE FRONT.
THAT BEING SAID...HAVE INCLUDED CHC SHOWERS INTO SATURDAY NIGHT.
THE FRONT CRAWLS TO JUST EAST OF MONTAUK BY SUNDAY AM. THUS...SILL
CARRYING AND CHANCE OF EARLY MORNING SHOWERS FOR EASTERN LI. AGAIN
SREF IS SLOWER WITH LINGERING SHOWERS INTO SUNDAY AFTERNOON.
HIGH PRESSURE WILL EVENTUALLY BUILDS IN ON MONDAY.
NEXT SHORTWAVE APPROACHES LATE TUESDAY WITH DIURNAL CONVECTION
THAT STRETCHES INTO THE NIGHT AND CONTINUES INTO WEDNESDAY. USED
30-40 POP...BUT THERE`S GOOD AGREEMENT WITH 12Z GFS AND ECMWF HERE
- SO CONFIDENCE IS FAIRLY GOOD.
HIGH PRESSURE THEN FOLLOWS FOR THURSDAY INTO FRIDAY.
ECMWF SHOWING A FAIRLY DEEP TROUGH FOR NEXT WEEKEND AS WELL.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY WILL MOVE SLOWLY...BUT
REMAIN TO THE WEST OF THE AREA THROUGH TONIGHT.
MULTIPLE CLUSTERS/LINES OF CONVECTION NEAR/IN THE FORECAST AREA
LATE THIS AFTN. CURRENT TIMING IN TAFS LOOKS GOOD...SO NO MAJOR
CHANGES MADE. FIRST LINE CURRENTLY MOVING THROUGH NYC
TERMINALS. WATCHING ANOTHER CLUSTER NEAR KTTN...BUT IT CURRENT
MOVEMENT INDICATES IT WILL REMAIN S OF NYC. ANOTHER LINE IN THE
LOWER HUDSON VALLEY IS TRACKING NE AND SHOULD REMAIN N OF
KHPN/KBDR UNLESS THEY BUILD ON THE SOUTHERN EDGE. MONITORING
CLOSELY. BRIEF MVFR TO LOCALLY IFR CONDS MAY OCCUR AS STORMS MOVE
THROUGH.
FOG AND LOW CLOUDS LIKELY RETURN THIS EVENING ALONG THE COAST
THEN EXPAND INLAND OVERNIGHT. LOW END MVFR CONDITIONS
LIKELY...WITH IFR PSBL...ESPECIALLY COASTAL TERMINALS.
SLY WINDS GENERALLY 10-15KT...WITH OCNL GUSTS AROUND 20 KT NYC
TERMINALS PSBL UNTIL 00Z.
SHOWERS/TS MAY MOVE IN AT TIMES EARLY TOMORROW MORNING BUT EXPECT
TS TO BE ISOLD UNTIL AFTERNOON. LOW CLOUDS AND FOG SHOULD MOSTLY
BURN OFF BY MID MORNING.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: WIND GUSTS MAY DIMINISH EARLIER THAN
FORECAST. WINDS MAY SHIFT TO THE W FOR AN HOUR OR SO AFTER TS
MOVE THROUGH. LOW CONFIDENCE IN TIMING OF LOW CLOUD DEVELOPMENT
OVERNIGHT.
KJFK FCSTER COMMENTS: WINDS MAY SHIFT TO THE W FOR AN HOUR OR SO
AFTER TS MOVE THROUGH. LOW CONFIDENCE IN TIMING OF LOW CLOUD
DEVELOPMENT OVERNIGHT.
KLGA FCSTER COMMENTS: WIND GUSTS MAY DIMINISH EARLIER THAN
FORECAST. WINDS MAY SHIFT TO THE W FOR AN HOUR OR SO AFTER TS
MOVE THROUGH. LOW CONFIDENCE IN TIMING OF LOW CLOUD DEVELOPMENT
OVERNIGHT.
KTEB FCSTER COMMENTS: WINDS MAY SHIFT TO THE W FOR AN HOUR OR SO
AFTER TS MOVE THROUGH. LOW CONFIDENCE IN TIMING OF LOW CLOUD
DEVELOPMENT OVERNIGHT.
KHPN FCSTER COMMENTS: WINDS MAY SHIFT TO THE W FOR AN HOUR OR SO
AFTER TS MOVE THROUGH. LOW CONFIDENCE IN TIMING OF LOW CLOUD
DEVELOPMENT OVERNIGHT.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS ANTICIPATED. LOW
CONFIDENCE IN TIMING OF LOW CLOUD DEVELOPMENT THIS EVENING.
OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRI-SAT...PERIODS OF IFR IN SCATTERED HEAVY SHOWERS AND TSTMS. LOW
CLOUDS AND FOG ALSO POSSIBLE OUTSIDE OF ANY STORMS AT NIGHT. GUSTY
SSE WINDS FRI AFTERNOON.
.SUN-TUE...VFR.
&&
.MARINE...
GENERALLY A WEAK PRES GRADIENT WILL KEEP GRADIENT WIND GUSTS BELOW
25 KT. THUNDERSTORMS DEVELOPING THIS EVENING...THEN AGAIN FRIDAY
THROUGH FRIDAY NIGHT...COULD RESULT IN THUNDERSTORM WIND GUSTS
GREATER THAN 34 KT. HEAVY RAIN WILL RESULT IN DIMINISHED VSBY...
RANGING FROM 1 TO 3 MILES.
THE PERSISTENT SOUTHERLY FLOW WILL PUSH SEAS UP AROUND 5 FT
STARTING FRIDAY NIGHT. A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS
MAY BE NEEDED FRIDAY NIGHT...BUT CONFIDENCE IS NOT HIGH ENOUGH TO
WARRANT ISSUING ONE AT THIS TIME...AS SEAS MAY HOVER AROUND 4 FT
AND NOT QUITE MAKE IT TO 5 FT.
SEAS MAY ON THE EASTERN HALF OF THE NEAR SHORE OCEAN
SATURDAY...BUT BASED ON WIND FORECAST...THINK WAVEWATCH MODEL IS
A BIT HIGH AND HAVE LOWERED THE FORECAST 0.5-1.0`.
SEAS AND WINDS ON SUNDAY INTO EARLY NEXT WEEK ARE FORECAST BELOW
SCA LEVELS.
&&
.HYDROLOGY...
A QUARTER TO A HALF INCH OF PRECIPITATION IS LIKELY THROUGH THIS
EVENING ACROSS THE LOWER HUDSON VALLEY INTO PORTIONS OF NE
NJ...WITH UP TO A TENTH OF AN INCH FARTHER TO THE EAST. HEAVY RAIN
MOVES INTO THE REGION FRIDAY THROUGH FRIDAY NIGHT...WITH 1.25-1.5"
QPF POSSIBLE OVER WESTERN ZONES AND UP TO AN INCH OVER EASTERN
ZONES. LOCAL FLOODING OF LOW LYING...POOR DRAINAGE AREAS AND SMALL
STREAMS IS POSSIBLE IN HEAVIER RAINFALL THIS EVENING AND AGAIN
FRIDAY-FRIDAY NIGHT.
HEAVIER RAIN POTENTIAL SHIFTS TO THE EAST ON SATURDAY FOR LI AND
CT. AGAIN...THE PROLONGED NATURE OF THE RAINFALL SUGGESTS ONLY LOCAL
PONDING/MINOR FLOOD POTENTIAL.
RIVER FLOODING IS NOT EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
355 PM EDT THU AUG 9 2012
.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT APPROACH TONIGHT THROUGH FRIDAY. A
SECONDARY LOW WILL FORM AND IMPACT THE AREA FRIDAY NIGHT THROUGH
SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS A PRE-FRONTAL TROUGH EDGES CLOSER TO WESTERN PORTIONS OF THE
CWA...SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND TRACK
EAST. ML MUCAPE VALUES REMAIN QUITE HIGH...AVERAGING 2000-3000
J/KG OVER THE AREA...BUT MOST OF THE MODELS HAVE THE STORMS BARELY
MAKING IT THROUGH NYC BEFORE ENDING JUST AS THEY APPROACH
FAIRFIELD AND NASSAU COUNTIES. ONLY THE HRRR MODEL HAS STORMS
GOING THROUGH NYC AND INTO WESTERN CT AND LONG ISLAND.
STORMS THE DEVELOPED ALONG THE NORTH SHORE OF LONG ISLAND IN
ASSOCIATION WITH THE SEA BREEZE BOUNDARY HAVE ENDED...AND DO NOT
THINK MUCH ADDITIONAL ACTIVITY WILL OCCUR FROM THAT BOUNDARY.
WILL FOLLOW THE GUIDANCE AND KEEP LIKELY POPS CONFINED TO FAR NW
ZONES...MAINLY ORANGE/ROCKLAND AND WESTERN PASSAIC COUNTIES...AND
HIGH CHANCE ALONG AND WEST OF THE HUDSON RIVER. ONCE STORMS FIRE
UP AND TRACK EAST...THEY WILL MOVE INTO AN ATMOSPHERE THAT REMAINS
UNSTABLE. MID-LEVEL STEERING CURRENT SEEMS LOW...SO STORMS WILL
TRACK FAIRLY SLOWLY. THIS WILL RESULT IN AREAS OF LOCALLY HEAVY
RAINFALL...WHICH COULD RESULT IN FLASH FLOODING. AT THE VERY
LEAST...URBAN/POOR DRAINAGE/SMALL STREAM FLOODING CAN BE EXPECTED.
IN ADDITION...STORMS ARE CAPABLE OF GUSTY WINDS AND FREQUENT AND
DANGEROUS LIGHTNING STRIKES.
STORMS TAPER OFF BY MIDNIGHT. LOW PRES OVER THE MIDWEST CONTINUES
TO MOVE INTO THE OH VALLEY...SO WILL KEEP AT LEAST SLIGHT CHANCE
TO LOW CHANCE POPS IN THE FORECAST THROUGH THE OVERNIGHT. WITH
ABUNDANT LOW LEVEL MOISTURE IN THE ATMOSPHERE...EXPECTING LOW
STRATUS/FOG TO DEVELOP AFTER MIDNIGHT.
WARM AND HUMID TONIGHT WITH LOWS IN THE MID 70S IN/AROUND NYC AND
IN THE UPPER 60S ELSEWHERE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
LOW PRES OVER THE GREAT LAKES MOVES INTO THE OH VALLEY FRIDAY
AFTERNOON AND INTENSIFIES AS IT THEN TRACKS OVER LAKE HURON. THIS
SYSTEM WILL PUSH A WARM FRONT ALONG THE EAST COAST AND THROUGH THE
REGION FROM SOUTH TO NORTH DURING THE DAY FRIDAY. AS THIS FRONT
TRACKS NORTH...IT WILL HAVE UPPER LEVEL SUPPORT FROM A MID LEVEL
SHORTWAVE TRACKING ALONG THE COAST. SHOWERS AND THUNDERSTORMS WILL
OVERSPREAD THE REGION FROM SOUTH TO NORTH...AND WITH ELEVATED
INSTABILITY OVER THE REGION...GUSTY WINDS AND FREQUENT LIGHTNING
CAN BE EXPECTED. A TROPICAL AIRMASS WILL OVERSPREAD THE REGION...
MAKING IT VERY WARM AND HUMID. WITH PWATS APPROACHING 2"...HEAVY
RAIN AND FLASH FLOODING IS POSSIBLE.
AS THE LOW INTENSIFIES OVER LAKE HURON LATE FRIDAY...A SECONDARY
LOW WILL FORM OVER THE DELMARVA...TRACK ALONG THE COAST...AND MOVE
INTO THE LOCAL AREA LATE FRIDAY THROUGH FRIDAY NIGHT. HEAVY RAIN
AND GUSTY WINDS ALONG WITH POSSIBLE FLASH FLOODING EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
SURFACE LOW OVER SOUTHERN ONTARIO SATURDAY AM BEINGS ITS GRADUALLY
FILLING PROCESS AS THE COLD FRONT FINALLY REACHES THE NYC METRO
AREA. THE INSTABILITY IS RATHER LIMITED AND HAVE FOCUSED MAINLY ON
THE PASSING NATURE OF SHOWERS AND CALLED IT ONLY ISOLATED FOR THE
THUNDERSTORM CHANCE. MAIN FOCUS FOR HEAVIER RAINFALL WOULD BE
EAST OF THE HUDSON - LONG ISLAND AND CT WITH RAINING SHOWERS. IN
ADDITION...THE BEST LIKELIHOOD OF SHOWERS WOULD BE THE MORNING.
IN TERMS OF MODELS...GOOD AGREEMENT IN THE DETERMINISTIC 12Z
RUNS...BUT 15Z SERF IS SUPPORTING A SLOWER PASSAGE OF THE FRONT.
THAT BEING SAID...HAVE INCLUDED CHC SHOWERS INTO SATURDAY NIGHT.
THE FRONT CRAWLS TO JUST EAST OF MONTAUK BY SUNDAY AM. THUS...SILL
CARRYING AND CHANCE OF EARLY MORNING SHOWERS FOR EASTERN LI. AGAIN
SREF IS SLOWER WITH LINGERING SHOWERS INTO SUNDAY AFTERNOON.
HIGH PRESSURE WILL EVENTUALLY BUILDS IN ON MONDAY.
NEXT SHORTWAVE APPROACHES LATE TUESDAY WITH DIURNAL CONVECTION
THAT STRETCHES INTO THE NIGHT AND CONTINUES INTO WEDNESDAY. USED
30-40 POP...BUT THERE`S GOOD AGREEMENT WITH 12Z GFS AND ECMWF HERE
- SO CONFIDENCE IS FAIRLY GOOD.
HIGH PRESSURE THEN FOLLOWS FOR THURSDAY INTO FRIDAY.
ECMWF SHOWING A FAIRLY DEEP TROUGH FOR NEXT WEEKEND AS WELL.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY WILL MOVE SLOWLY
TODAY...BUT REMAIN TO THE WEST OF THE AREA THROUGH TONIGHT.
SCT TS CONTINUE TO DEVELOP ACROSS ERN PA...WITH ACTIVITY MORE
ISOLATED ON LOCAL SEA BREEZES. TS TO THE WEST ARE SLOW
MOVERS...AND WOULD NOT ARRIVE TO NEAR NYC UNTIL AFT 21Z. BRIEF
SUB-VFR MAY OCCUR AS STORMS MOVE THROUGH--BUT THEY WILL LIKELY BE
IN A WKNG STATE AND CONFIDENCE IN THIS IS LOW.
FOG AND LOW CLOUDS RETURN THIS EVENING ALONG THE COAST THEN EXPAND
INLAND OVERNIGHT. LOW END MVFR CONDITIONS LIKELY...WITH IFR
PSBL...ESPECIALLY COASTAL TERMINALS.
WINDS GENERALLY SSE 10-12KT THIS AFTERNOON...WITH OCNL G16-18KT PSBL
UNTIL 22Z.
SHOWERS/TS MAY MOVE IN AT TIMES EARLY TOMORROW MORNING BUT EXPECT
TS TO BE ISOLD UNTIL AFTERNOON. LOW CLOUDS AND FOG SHOULD MOSTLY
BURN OFF BY MID MORNING.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: WIND GUSTS WILL BE OCCASIONAL THIS AFTERNOON.
AMENDMENTS POSSIBLE FOR TS TIMING THIS AFTERNOON. WINDS MAY SHIFT
TO THE W FOR AN HOUR OR SO AFTER TS MOVE THROUGH. LOW CONFIDENCE
IN TIMING OF LOW CLOUD DEVELOPMENT OVERNIGHT.
KJFK FCSTER COMMENTS: WIND GUSTS WILL BE OCCASIONAL THIS AFTERNOON.
AMENDMENTS POSSIBLE FOR TS TIMING THIS AFTERNOON. WINDS MAY SHIFT
TO THE W FOR AN HOUR OR SO AFTER TS MOVE THROUGH. LOW CONFIDENCE
IN TIMING OF LOW CLOUD DEVELOPMENT THIS EVENING.
KLGA FCSTER COMMENTS: WIND GUSTS WILL BE OCCASIONAL THIS AFTERNOON.
AMENDMENTS POSSIBLE FOR TS TIMING THIS AFTERNOON. WINDS MAY SHIFT
TO THE W FOR AN HOUR OR SO AFTER TS MOVE THROUGH. LOW CONFIDENCE
IN TIMING OF LOW CLOUD DEVELOPMENT OVERNIGHT.
KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TS TIMING THIS
AFTERNOON. WINDS MAY SHIFT TO THE W FOR AN HOUR OR SO AFTER TS
MOVE THROUGH. LOW CONFIDENCE IN TIMING OF LOW CLOUD DEVELOPMENT
OVERNIGHT.
KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TS TIMING THIS
AFTERNOON. WINDS MAY SHIFT TO THE W FOR AN HOUR OR SO AFTER TS
MOVE THROUGH. LOW CONFIDENCE IN TIMING OF LOW CLOUD DEVELOPMENT
OVERNIGHT.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS ANTICIPATED. LOW
CONFIDENCE IN TIMING OF LOW CLOUD DEVELOPMENT THIS EVENING.
OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRI-SAT...PERIODS OF IFR IN SCATTERED HEAVY SHOWERS AND TSTMS. LOW
CLOUDS AND FOG ALSO POSSIBLE OUTSIDE OF ANY STORMS AT NIGHT. GUSTY
SSE WINDS FRI AFTERNOON.
.SUN-TUE...VFR.
&&
.MARINE...
GENERALLY A WEAK PRES GRADIENT WILL KEEP GRADIENT WIND GUSTS BELOW
25 KT. THUNDERSTORMS DEVELOPING THIS EVENING...THEN AGAIN FRIDAY
THROUGH FRIDAY NIGHT...COULD RESULT IN THUNDERSTORM WIND GUSTS
GREATER THAN 34 KT. HEAVY RAIN WILL RESULT IN DIMINISHED VSBY...
RANGING FROM 1 TO 3 MILES.
THE PERSISTENT SOUTHERLY FLOW WILL PUSH SEAS UP AROUND 5 FT
STARTING FRIDAY NIGHT. A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS
MAY BE NEEDED FRIDAY NIGHT...BUT CONFIDENCE IS NOT HIGH ENOUGH TO
WARRANT ISSUING ONE AT THIS TIME...AS SEAS MAY HOVER AROUND 4 FT
AND NOT QUITE MAKE IT TO 5 FT.
SEAS MAY ON THE EASTERN HALF OF THE NEAR SHORE OCEAN
SATURDAY...BUT BASED ON WIND FORECAST...THINK WAVEWATCH MODEL IS
A BIT HIGH AND HAVE LOWERED THE FORECAST 0.5-1.0`.
SEAS AND WINDS ON SUNDAY INTO EARLY NEXT WEEK ARE FORECAST BELOW
SCA LEVELS.
&&
.HYDROLOGY...
A QUARTER TO A HALF INCH OF PRECIPITATION IS LIKELY THROUGH THIS
EVENING ACROSS THE LOWER HUDSON VALLEY INTO PORTIONS OF NE
NJ...WITH UP TO A TENTH OF AN INCH FARTHER TO THE EAST. HEAVY RAIN
MOVES INTO THE REGION FRIDAY THROUGH FRIDAY NIGHT...WITH 1.25-1.5"
QPF POSSIBLE OVER WESTERN ZONES AND UP TO AN INCH OVER EASTERN
ZONES. LOCAL FLOODING OF LOW LYING...POOR DRAINAGE AREAS AND SMALL
STREAMS IS POSSIBLE IN HEAVIER RAINFALL THIS EVENING AND AGAIN
FRIDAY-FRIDAY NIGHT.
HEAVIER RAIN POTENTIAL SHIFTS TO THE EAST ON SATURDAY FOR LI AND
CT. AGAIN...THE PROLONGED NATURE OF THE RAINFALL SUGGESTS ONLY LOCAL
PONDING/MINOR FLOOD POTENTIAL.
RIVER FLOODING IS NOT EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MPS
NEAR TERM...MPS
SHORT TERM...MPS
LONG TERM...JST
AVIATION...PW
MARINE...MPS/JST
HYDROLOGY...MPS/JST
AREA FORECAST DISCUSSION
NWS MIAMI FL
250 PM EDT THU AUG 9 2012
.AVIATION...
OUTSIDE OF A BRIEF SHOWER SPREADING ASHORE ALONG THE EAST
COAST...VFR CONDITIONS SHOULD PERSIST THROUGH REMAINDER OF THE DAY
TODAY. HOWEVER...FOR APF...WILL KEEP VCTS IN THIS TAF PACKAGE FOR
THE LATE AFTERNOON AND EVENING PERIODS WHERE THE BEST CHANCE FOR
SCATTERED SHOWERS AND STORMS WILL BE. OVERNIGHT...DEEP LAYER
MOISTURE IS FORECAST TO SPREAD OVER THE AREA FROM THE
SOUTHEAST...WHICH WILL BRING THE RAINFALL CHANCES BACK TO THE
AREA...ESPECIALLY ACROSS THE EAST COAST TERMINALS LATE TONIGHT
THROUGH THE FIRST PORTION OF THE DAY FRIDAY. THEREFORE...WILL
INCLUDE VCSH FOR ALL EAST COAST SITES LATE TONIGHT...THEN VCTS FOR
APF LATER IN THE PERIOD. WINDS WILL REMAIN MOSTLY LIGHT OUT OF THE
SOUTHEAST...THEN VEER TO THE SOUTH OVER THE WEEKEND. 85/AG
&&
.PREV DISCUSSION... /ISSUED 1043 AM EDT THU AUG 9 2012/
UPDATE...THE LATEST HRRR SHOWS QUITE A BIT OF CONVECTION
DEVELOPING OVER THE INTERIOR AND ESPECIALLY THE GULF COAST/NAPLES
AREA THIS AFTERNOON. THE MIAMI SOUNDING THIS MORNING SHOWS
SUFFICIENT MOISTURE FOR CONVECTION...WITH A PWAT OF 1.62 INCHES
AND THE DRIEST AIR IN THE MID LEVELS. HAVE INCREASED THE COVERAGE
OF SHOWERS/TSTORMS FOR THE INTERIOR AND GULF COAST...WITH THE
HIGHEST POPS ACROSS THE NAPLES AREA. WEAK LAPSE RATES ARE PRESENT
BUT GIVEN STRONG HEATING AND MID LEVEL DRY AIR...A FEW STRONG
STORMS ARE POSSIBLE WHERE CONVERGENCE IS MAXIMIZED WHICH LOOKS TO
BE ACROSS THE GREATER NAPLES AREA LATE THIS AFTERNOON. STRONG WIND
GUSTS TO AROUND 50 MPH WOULD BE THE MAIN CONCERN IN THE STRONGEST
STORMS...AS WELL AS FREQUENT LIGHTNING. /GREGORIA
PREV DISCUSSION... /ISSUED 655 AM EDT THU AUG 9 2012/
AVIATION...
EASTERLY FLOW EXPECTED TO CONTINUE THROUGH THE PERIOD AT ALL EAST
COAST SITES WITH VFR CONDITIONS. KEPT VCTS MENTION AT KAPF AS A
WEAK GULF COAST SEA BREEZE COULD DEVELOP DURING THE EARLY
AFTERNOON HOURS RESULTING IN SCATTERED SHRA/TSTMS.
PREV DISCUSSION... /ISSUED 326 AM EDT THU AUG 9 2012/
SHORT TERM...TODAY THROUGH SATURDAY...A DEEP LAYER ATLANTIC
RIDGE SHOULD REMAIN ACROSS SOUTH CENTRAL FLORIDA TODAY AND
TONIGHT. WATER VAPOR IMAGES SHOW A RATHER DRY AIRMASS BEING
ADVECTED WESTWARD ACROSS THE NRN BAHAMAS AND THE SOUTHERN PORTIONS
OF THE PENINSULA BY THE DEEP EASTERLY FLOW AROUND THE BASE OF THIS
RIDGE. WL EXPECT THIS DRY AIR, COMBINED WITH SUBSIDENCE ALOFT, TO
KEEP PRECIP ACTIVITY TO A MINIMUM ACROSS MOST AREAS TODAY.
HOWEVER, LOCAL BREEZES AND DIURNAL HEATING COULD STILL LEAD TO THE
DEVELOPMENT OF A FEW SHWRS/TSTMS ACROSS INTERIOR PORTIONS LATER
THIS AFTERNOON. WL EXPECT THIS TO BE FOCUSED MORE TOWARD THE
WESTERN INTERIOR AND WEST OF LAKE OKEECHOBEE. PLENTY OF SUNSHINE
TODAY WILL ALSO LEAD TO AFTERNOON TEMPS SOARING INTO THE LOWER TO
MID 90S WITH HEAT INDICES AT OR ABOVE 100 DEGREES ACROSS MOST
AREAS, EXCEPT FOR THE IMMEDIATE EAST COAST.
A RATHER ACTIVE TROPICAL WAVE WAS LOCATED ACROSS THE CENTRAL
CARIBBEAN SEA EARLIER THIS MORNING MOVING WEST AT AROUND 10-15
KTS. AN UPPER LOW WAS ALSO INDICATED JUST NW OF JAMAICA AND
INTERACTING WITH THE WAVE. A LARGE ENVELOP OF MOISTURE WAS
ASSOCIATED WITH BOTH SYSTEMS. MOISTURE SHOULD BEGIN TO INCREASE
GRADUALLY OVER S. FLORIDA AS THE UPPER LOW MOVES TO THE WESTERN
TIP OF CUBE FRIDAY, BUT WILL BE FURTHER ENHANCED AS THE TROPICAL
WAVE MOVES ACROSS THE LOCAL AREA FRI NIGHT AND SATURDAY. DUE TO
THE NATURE OF THESE SYSTEMS AND THE COMPLEXITY OF THE INTERACTIONS
BETWEEN UPPER LOWS AND TROPICAL WAVES (BASED ON PAST EXPERIENCE),
DECIDED TO INCREASE THE CHANCES OF RAIN WITH CAUTION FOR BOTH
FRIDAY AND SATURDAY AND NOT GO AS HIGH AS GFS. IF THE RIGHT
COMBINATION, ENHANCED LOW LEVEL CONVERGENCE ASSOCIATED WITH THE
WAVE AND UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE LOW, COMES TO
PLAY, THE CHANCES FOR RAIN COULD BE SIGNIFICANTLY HIGHER.
LONG TERM...SUNDAY THROUGH WEDNESDAY...AN UPPER RIDGE SHOULD
BEGIN TO BUILD ACROSS THE REGION WHILE A LOW LEVEL ATLANTIC RIDGE
IS EXPECTED TO BUILD WESTWARD. THIS WILL TO LIMIT THE PRECIP
ACTIVITY BY WAY OF MID/UPPER LVL SUBSIDENCE AND WILL TEND TO FOCUS
AFTERNOON SHWRS/TSTMS MORE TOWARD INTERIOR AND WESTWARD PORTIONS
OF S. FLORIDA. NIGHTTIME AND EARLY MORNING PRECIP ACTIVITY COULD
ALSO OCCUR ALONG EASTERN AREAS.
MARINE...A LIGHT TO MODERATE SE FLOW SHOULD PREVAIL THROUGH THE
END OF THE WEEK WITH A SHIFT TO MORE SOUTHERLY BY THE WEEKEND.
SEAS ARE EXPECTED TO BE BELOW 4 FT THROUGH THE PERIOD.
HOWEVER...BOTH SEAS AND WINDS COULD BE SIGNIFICANTLY HIGHER IN THE
VICINITY OF SHOWERS AND THUNDERSTORMS...ESPECIALLY FRI NIGHT AND
SATURDAY AS THE TROPICAL WAVE MOVES THROUGH.
FIRE WEATHER...NO CONCERNS AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 88 77 90 / 20 70 50 60
FORT LAUDERDALE 80 88 79 90 / 30 70 50 60
MIAMI 79 88 78 90 / 30 70 50 60
NAPLES 76 89 76 91 / 20 50 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
637 PM EDT THU AUG 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 226 PM EDT THU AUG 9 2012
LOW PRESSURE OVER SOUTHEASTERN ILLINOIS WILL PUSH NORTHEAST
TONIGHT...DRAGGING A COLD FRONT ACROSS CENTRAL INDIANA THIS
EVENING. THIS IN COMBINATION WITH DAYTIME HEATING WILL ALLOW FOR
SCATTERED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON AND THIS
EVENING ALONG AND AHEAD OF THE FRONT.
THE LOW WILL SLOWLY PUSH TO THE EASTERN GREAT LAKES ON FRIDAY AND
SATURDAY...ALLOWING COOLER AIR ON NORTHWEST WINDS AND DRY WEATHER TO
ARRIVE IN CENTRAL INDIANA FOR THE WEEKEND.
COOLER WEATHER IS EXPECTED MUCH OF NEXT WEEK. A LOW PRESSURE
SYSTEM PASSING TO THE SOUTH ON WEDNESDAY AND A COLD FRONT
APPROACHING ON THURSDAY NIGHT AND FRIDAY WILL BRING OUR NEXT
CHANCES FOR SHOWERS AND STORMS.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 226 PM EDT THU AUG 9 2012
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS LOW PRESSURE NEAR STL
WITH A COLD FRONT EXTENDING SW INTO NW ARKANSAS AND A WARM FRONT
STRETCHING SE ACROSS SOUTHERN ILLINOIS AND SOUTHERN INDIANA.
VISIBLE PICTURE SHOW PLENTY OF CLOUD COVER ACROSS CENTRAL
INDIANA...HOWEVER CLEARING WAS IN PLACE ACROSS CENTRAL AND
SOUTHERN ILLINOIS. DEW POINT TEMPS REMAINED MOIST IN THE 60S. RADAR
SHOWS TSRA DEVELOPING OVER CENTRAL KENTUCKY AND SW OHIO.
MAIN FORECAST CHALLENGE WILL BE POPS.
AS THE LOW PRESSURE SYSTEM NEAR STL IS EXPECTED TO TRACK NE
TONIGHT MORE FAVORABLE CONDITIONS ARE EXPECTED OVER ILLINOIS FOR
CONVECTION DEVELOPMENT. LIFTED INDICES REMAIN NEGATIVE THIS
AFTERNOON AHEAD OF THE FRONT WITH FAVORABLE CAPE IN EXCESS OF 1300
J/KG. HRRR DEVELOPS BEST CONVECTION ALONG THE COLD FRONT WHICH
SHOULD PASS ACROSS CENTRAL INDIANA AFTER 00Z. 0-3KM SHEAR AXIS OF
NEAR 25-30 KNTS PUSH ACROSS THE STATE WITH ET FRONT AS WELL. THUS
WILL KEEP TSRA MENTION WITH LIKELY OR BETTER POPS FOR TONIGHT.
AS THE FRONT DEPARTS TOWARD 12Z FORECAST SOUNDINGS SHOW MUCH DRIER
AIR ARRIVING. WILL TREND POPS DOWNWARD AFTER 06Z. AS FOR LOWS...WILL
USE A BLEND OF MAVMOS AND METMOS GIVEN THE CHANGE IN AIRMASS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 226 PM EDT THU AUG 9 2012
MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN AND
WILL USE A BLEND. MAIN FORECAST CHALLENGE WILL BE TEMPS THROUGH THE
PERIOD.
NAM/GFS AGREE THAT A DEEP UPPER LOW EXPECTED TO BE OVER NORTHERN
INDIANA ON FRIDAY WILL SLOWLY DRIFT NORTHEAST TO THE GREAT LAKES.
ABUNDANT CLOUD COVER IS EXPECTED TO REMAIN ACROSS THE AREA ON
FRIDAY AS THE LOW DRIFTS TO THE NORTH. TIME HEIGHT SECTIONS SHOW
GOOD LOWER LEVEL MOISTURE. FURTHERMORE FORECAST SOUNDINGS SHOW
CONVECTIVE TEMPERATURES IN THE LOWER 70S THAT COULD RESULT IN SOME
ISOLATED POP UP AFTERNOON RAIN SHOWERS. WILL TREND HIGHS COOLER
THAN MAVMOS GIVEN THE EXPECTED CLOUDS AND THE COLD AIR ADVECTION.
LINGERING CLOUDS AND ANY ISOLATED SHRA WILL DISSIPATE ON FRIDAY
NIGHT AS UPPER LOW PULLS NORTHEAST AND ANY DAYTIME HEATING WANES.
EVEN BETTER DRYING APPEARS IN THE FORECAST SOUNDINGS IN ON FRIDAY
NIGHT AND SATURDAY...CONTINUING INTO SATURDAY NIGHT AS HIGH
PRESSURE REMAINS ACROSS THE AREA. GIVEN THE COLD AIR ADVECTION AS
850MB TEMPS FALL NEAR 10C WILL TREND HIGHS AND LOWS COOLER THAN
MAVMOS...WITH MOSTLY CLEAR NIGHTS AND A SUNNY SATURDAY.
SURFACE HIGH REMAINS IN CONTROL IN SUNDAY ACROSS THE OHIO
VALLEY...HOWEVER ALOFT A SHORT WAVE IS APPROACHING AND PUSHING
THROUGH INDIANA. SURFACE FLOW DOES NOT APPEAR TO OPEN AND ALLOW
FOR THE ADDITION OF GULF MOISTURE. THUS FOR NOW WILL HOLD OFF ON
POPS FOR SUNDAY UNTIL BETTER CONFIDENCE IS REVEALED IN LOWER LEVEL
MOISTURE....BUT WILL INCREASE CLOUD COVERAGE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 226 PM EDT THU AUG 9 2012
ENSEMBLES SUGGEST A FAIRLY PROGRESSIVE FLOW ACROSS THE NORTHERN
PARTS OF THE COUNTRY...WHILE THE SUB TROPICAL RIDGE HOLDS FROM THE
SOUTHERN ROCKIES EASTWARD ACROSS THE GULF COAST STATES. ANOTHER
UPPER DISTURBANCE IS EXPECTED TO DROP INTO THE GREAT LAKES AND OHIO
VALLEY EARLY NEXT WEEK...AND THEN LIFT OFF TO THE EAST BY THE MIDDLE
OF NEXT WEEK. ENSEMBLES SUGGEST THE BEST THREAT FOR PRECIPITATION
WITH THIS SYSTEM WILL BE MONDAY AND MONDAY NIGHT. WILL GO WITH
CHANCE POPS AT THOSE TIMES. HEIGHTS ARE EXPECTED TO RISE TOWARDS THE
MIDDLE OF NEXT WEEK AS TROUGH LIFTS OFF TO THE EAST...SO WILL
CONTINUE WITH A DRY FORECAST FOR TUESDAY AND WEDNESDAY.
BY THURSDAY...THERE ARE INDICATIONS THAT THE HEAT RIDGE MAY TRY TO
BUILD BACK INTO THE SOUTHERN PLAINS. THE ENSEMBLES SUGGEST ANOTHER
DISTURBANCE MAY RIDE OVER THE DEVELOPING RIDGE INTO THE LOCAL AREA
BY THURSDAY. WILL CONTINUE WITH CHANCE POPS AT THAT TIME.
&&
.AVIATION /DISCUSSION FOR THE 100000Z TAF ISSUANCE/...
ISSUED AT 637 PM EDT THU AUG 9 2012
THUNDERSTORM ACTIVITY WILL BE INCREASING THIS EVENING AS A COLD
FRONT DROPS SOUTHEAST ACROSS THE TERMINALS AND AN UPPER LOW PIVOTS
SOUTHEAST TO NORTHERN ILLINOIS AND THEN NORTHERN INDIANA. WILL GO
WITH TEMPO THUNDERSTORM GROUPS THROUGH 05Z AT HUF AND LAF AND IND
AND BMG TIL 06Z. WILL ALSO PERHAPS ADD THUNDER TO THE PRVAILING
GROUP JUST PRIOR TO ISSUANCE TIME...IF IT CAN BE DONE WITH GOOD
CONFIDENCE. MODELS AND SOME UPSTREAM OBSERVATIONS SUGGEST MVFR
CONDITIONS AFTER 06Z. WITH SURFACE WINDS PICKING UP...MORE CONFIDENT
ON STRATUS THAN FOG. WITH THE UPPER LOW IN THE VICINITY...COLD AIR
ALOFT AND LINGERING LOW LEVEL MOISTURE...PLENTY OF DIURNAL MVFR CU
WILL BE AROUND FRIDAY BEFORE CLEARING COMMENCES AT SUNSET AS HIGH
PRESSURE BUILDS IN FROM THE MISSISSIPPI VALLEY.
OTHERWISE...SOUTHWEST WINDS AT IND AND BMG SHOULD BECOME NORTHWEST
AROUND 02Z WHEN THE FRONT MOVES THROUGH. WINDS WILL INCREASE TO NEAR
10 KNOTS TOWARD 12Z AND 10 TO 15 KNOTS AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
445 PM EDT THU AUG 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 226 PM EDT THU AUG 9 2012
LOW PRESSURE OVER SOUTHEASTERN ILLINOIS WILL PUSH NORTHEAST
TONIGHT...DRAGGING A COLD FRONT ACROSS CENTRAL INDIANA THIS
EVENING. THIS IN COMBINATION WITH DAYTIME HEATING WILL ALLOW FOR
SCATTERED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON AND THIS
EVENING ALONG AND AHEAD OF THE FRONT.
THE LOW WILL SLOWLY PUSH TO THE EASTERN GREAT LAKES ON FRIDAY AND
SATURDAY...ALLOWING COOLER AIR ON NORTHWEST WINDS AND DRY WEATHER TO
ARRIVE IN CENTRAL INDIANA FOR THE WEEKEND.
COOLER WEATHER IS EXPECTED MUCH OF NEXT WEEK. A LOW PRESSURE
SYSTEM PASSING TO THE SOUTH ON WEDNESDAY AND A COLD FRONT
APPROACHING ON THURSDAY NIGHT AND FRIDAY WILL BRING OUR NEXT
CHANCES FOR SHOWERS AND STORMS.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 226 PM EDT THU AUG 9 2012
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS LOW PRESSURE NEAR STL
WITH A COLD FRONT EXTENDING SW INTO NW ARKANSAS AND A WARM FRONT
STRETCHING SE ACROSS SOUTHERN ILLINOIS AND SOUTHERN INDIANA.
VISIBLE PICTURE SHOW PLENTY OF CLOUD COVER ACROSS CENTRAL
INDIANA...HOWEVER CLEARING WAS IN PLACE ACROSS CENTRAL AND
SOUTHERN ILLINOIS. DEW POINT TEMPS REMAINED MOIST IN THE 60S. RADAR
SHOWS TSRA DEVELOPING OVER CENTRAL KENTUCKY AND SW OHIO.
MAIN FORECAST CHALLENGE WILL BE POPS.
AS THE LOW PRESSURE SYSTEM NEAR STL IS EXPECTED TO TRACK NE
TONIGHT MORE FAVORABLE CONDITIONS ARE EXPECTED OVER ILLINOIS FOR
CONVECTION DEVELOPMENT. LIFTED INDICES REMAIN NEGATIVE THIS
AFTERNOON AHEAD OF THE FRONT WITH FAVORABLE CAPE IN EXCESS OF 1300
J/KG. HRRR DEVELOPS BEST CONVECTION ALONG THE COLD FRONT WHICH
SHOULD PASS ACROSS CENTRAL INDIANA AFTER 00Z. 0-3KM SHEAR AXIS OF
NEAR 25-30 KNTS PUSH ACROSS THE STATE WITH ET FRONT AS WELL. THUS
WILL KEEP TSRA MENTION WITH LIKELY OR BETTER POPS FOR TONIGHT.
AS THE FRONT DEPARTS TOWARD 12Z FORECAST SOUNDINGS SHOW MUCH DRIER
AIR ARRIVING. WILL TREND POPS DOWNWARD AFTER 06Z. AS FOR LOWS...WILL
USE A BLEND OF MAVMOS AND METMOS GIVEN THE CHANGE IN AIRMASS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 226 PM EDT THU AUG 9 2012
MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN AND
WILL USE A BLEND. MAIN FORECAST CHALLENGE WILL BE TEMPS THROUGH THE
PERIOD.
NAM/GFS AGREE THAT A DEEP UPPER LOW EXPECTED TO BE OVER NORTHERN
INDIANA ON FRIDAY WILL SLOWLY DRIFT NORTHEAST TO THE GREAT LAKES.
ABUNDANT CLOUD COVER IS EXPECTED TO REMAIN ACROSS THE AREA ON
FRIDAY AS THE LOW DRIFTS TO THE NORTH. TIME HEIGHT SECTIONS SHOW
GOOD LOWER LEVEL MOISTURE. FURTHERMORE FORECAST SOUNDINGS SHOW
CONVECTIVE TEMPERATURES IN THE LOWER 70S THAT COULD RESULT IN SOME
ISOLATED POP UP AFTERNOON RAIN SHOWERS. WILL TREND HIGHS COOLER
THAN MAVMOS GIVEN THE EXPECTED CLOUDS AND THE COLD AIR ADVECTION.
LINGERING CLOUDS AND ANY ISOLATED SHRA WILL DISSIPATE ON FRIDAY
NIGHT AS UPPER LOW PULLS NORTHEAST AND ANY DAYTIME HEATING WANES.
EVEN BETTER DRYING APPEARS IN THE FORECAST SOUNDINGS IN ON FRIDAY
NIGHT AND SATURDAY...CONTINUING INTO SATURDAY NIGHT AS HIGH
PRESSURE REMAINS ACROSS THE AREA. GIVEN THE COLD AIR ADVECTION AS
850MB TEMPS FALL NEAR 10C WILL TREND HIGHS AND LOWS COOLER THAN
MAVMOS...WITH MOSTLY CLEAR NIGHTS AND A SUNNY SATURDAY.
SURFACE HIGH REMAINS IN CONTROL IN SUNDAY ACROSS THE OHIO
VALLEY...HOWEVER ALOFT A SHORT WAVE IS APPROACHING AND PUSHING
THROUGH INDIANA. SURFACE FLOW DOES NOT APPEAR TO OPEN AND ALLOW
FOR THE ADDITION OF GULF MOISTURE. THUS FOR NOW WILL HOLD OFF ON
POPS FOR SUNDAY UNTIL BETTER CONFIDENCE IS REVEALED IN LOWER LEVEL
MOISTURE....BUT WILL INCREASE CLOUD COVERAGE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 226 PM EDT THU AUG 9 2012
ENSEMBLES SUGGEST A FAIRLY PROGRESSIVE FLOW ACROSS THE NORTHERN
PARTS OF THE COUNTRY...WHILE THE SUB TROPICAL RIDGE HOLDS FROM THE
SOUTHERN ROCKIES EASTWARD ACROSS THE GULF COAST STATES. ANOTHER
UPPER DISTURBANCE IS EXPECTED TO DROP INTO THE GREAT LAKES AND OHIO
VALLEY EARLY NEXT WEEK...AND THEN LIFT OFF TO THE EAST BY THE MIDDLE
OF NEXT WEEK. ENSEMBLES SUGGEST THE BEST THREAT FOR PRECIPITATION
WITH THIS SYSTEM WILL BE MONDAY AND MONDAY NIGHT. WILL GO WITH
CHANCE POPS AT THOSE TIMES. HEIGHTS ARE EXPECTED TO RISE TOWARDS THE
MIDDLE OF NEXT WEEK AS TROUGH LIFTS OFF TO THE EAST...SO WILL
CONTINUE WITH A DRY FORECAST FOR TUESDAY AND WEDNESDAY.
BY THURSDAY...THERE ARE INDICATIONS THAT THE HEAT RIDGE MAY TRY TO
BUILD BACK INTO THE SOUTHERN PLAINS. THE ENSEMBLES SUGGEST ANOTHER
DISTURBANCE MAY RIDE OVER THE DEVELOPING RIDGE INTO THE LOCAL AREA
BY THURSDAY. WILL CONTINUE WITH CHANCE POPS AT THAT TIME.
&&
.AVIATION /DISCUSSION FOR THE 092100Z TAF UPDATES/...
ISSUED AT 445 PM EDT THU AUG 9 2012
THUNDERSTORMS ARE TAKING THEIR TIME DEVELOPING THIS AFTERNOON BUT
WITH LITTLE TO NO CAP...SHOULD NOT TAKE LONG. FOR THE UPDATE...TOOK
OUT UNNECESSARY HIGH LEVEL CEILINGS AND MADE MINOR TWEAKS TO WINDS.
OTHERWISE...NO CHANGES.
PREVIOUS DISCUSSION FOLLOWS....
SOME LOW POTENTIAL FOR DISORGANIZED CONVECTION EXPECTED TO LINGER
THROUGH THE MID AFTERNOON HOURS OVER THE TAF SITES AS WARM ADVECTION
CONTINUES OVER A SURFACE BOUNDARY LOCATED SOUTH OF THE OHIO RIVER.
MOST OF THE STRONGER INSTABILITY HAS BEEN SWEPT OUT OF THE LOCAL
AREA DUE TO CONVECTION EARLY THIS MORNING...SO THERE IS SOME DOUBT
ABOUT HOW MUCH CONVECTION MAY REDEVELOP LATER THIS AFTERNOON.
APPEARS THE BEST CHANCES FOR CONVECTION WILL BE WITH A COLD
FRONT...WHICH WILL DROP SOUTHEAST ACROSS THE TAF SITES ROUGHLY IN
THE 092300Z-100400Z TIME FRAME. WILL CONCENTRATE THE THUNDER THREAT
DURING THESE TIMES IN THE FORECAST. BRIEF IFR VISIBILITY
RESTRICTIONS LIKELY IN THE HEAVIER CELLS. CONVECTIVE CLOUD BASES
030-040.
OUTSIDE OF ANY CONVECTION...CEILINGS ABOVE 050/SURFACE WINDS BELOW
12 KTS EXPECTED FOR THE MOST PART THROUGH 100600Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
227 PM EDT THU AUG 9 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM
AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 226 PM EDT THU AUG 9 2012
LOW PRESSURE OVER SOUTHEASTERN ILLINOIS WILL PUSH NORTHEAST
TONIGHT...DRAGGING A COLD FRONT ACROSS CENTRAL INDIANA THIS
EVENING. THIS IN COMBINATION WITH DAYTIME HEATING WILL ALLOW FOR
SCATTERED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON AND THIS
EVENING ALONG AND AHEAD OF THE FRONT.
THE LOW WILL SLOWLY PUSH TO THE EASTERN GREAT LAKES ON FRIDAY AND
SATURDAY...ALLOWING COOLER AIR ON NORTHWEST WINDS AND DRY WEATHER TO
ARRIVE IN CENTRAL INDIANA FOR THE WEEKEND.
COOLER WEATHER IS EXPECTED MUCH OF NEXT WEEK. A LOW PRESSURE
SYSTEM PASSING TO THE SOUTH ON WEDNESDAY AND A COLD FRONT
APPROACHING ON THURSDAY NIGHT AND FRIDAY WILL BRING OUR NEXT
CHANCES FOR SHOWERS AND STORMS.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 226 PM EDT THU AUG 9 2012
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS LOW PRESSURE NEAR STL
WITH A COLD FRONT EXTENDING SW INTO NW ARKANSAS AND A WARM FRONT
STRETCHING SE ACROSS SOUTHERN ILLINOIS AND SOUTHERN INDIANA.
VISIBLE PICTURE SHOW PLENTY OF CLOUD COVER ACROSS CENTRAL
INDIANA...HOWEVER CLEARING WAS IN PLACE ACROSS CENTRAL AND
SOUTHERN ILLINOIS. DEW POINT TEMPS REMAINED MOIST IN THE 60S. RADAR
SHOWS TSRA DEVELOPING OVER CENTRAL KENTUCKY AND SW OHIO.
MAIN FORECAST CHALLENGE WILL BE POPS.
AS THE LOW PRESSURE SYSTEM NEAR STL IS EXPECTED TO TRACK NE
TONIGHT MORE FAVORABLE CONDITIONS ARE EXPECTED OVER ILLINOIS FOR
CONVECTION DEVELOPMENT. LIFTED INDICES REMAIN NEGATIVE THIS
AFTERNOON AHEAD OF THE FRONT WITH FAVORABLE CAPE IN EXCESS OF 1300
J/KG. HRRR DEVELOPS BEST CONVECTION ALONG THE COLD FRONT WHICH
SHOULD PASS ACROSS CENTRAL INDIANA AFTER 00Z. 0-3KM SHEAR AXIS OF
NEAR 25-30 KNTS PUSH ACROSS THE STATE WITH ET FRONT AS WELL. THUS
WILL KEEP TSRA MENTION WITH LIKELY OR BETTER POPS FOR TONIGHT.
AS THE FRONT DEPARTS TOWARD 12Z FORECAST SOUNDINGS SHOW MUCH DRIER
AIR ARRIVING. WILL TREND POPS DOWNWARD AFTER 06Z. AS FOR
LOWS...WILL USE A BLEND OF MAVMOS AND METMOS GIVEN THE CHANGE IN AIRMASS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 226 PM EDT THU AUG 9 2012
MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN AND
WILL USE A BLEND. MAIN FORECAST CHALLENGE WILL BE TEMPS THROUGH THE PERIOD.
NAM/GFS AGREE THAT A DEEP UPPER LOW EXPECTED TO BE OVER NORTHERN
INDIANA ON FRIDAY WILL SLOWLY DRIFT NORTHEAST TO THE GREAT LAKES.
ABUNDANT CLOUD COVER IS EXPECTED TO REMAIN ACROSS THE AREA ON
FRIDAY AS THE LOW DRIFTS TO THE NORTH. TIME HEIGHT SECTIONS SHOW
GOOD LOWER LEVEL MOISTURE. FURTHERMORE FORECAST SOUNDINGS SHOW
CONVECTIVE TEMPERATURES IN THE LOWER 70S THAT COULD RESULT IN SOME
ISOLATED POP UP AFTERNOON RAIN SHOWERS. WILL TREND HIGHS COOLER
THAN MAVMOS GIVEN THE EXPECTED CLOUDS AND THE COLD AIR ADVECTION.
LINGERING CLOUDS AND ANY ISOLATED SHRA WILL DISSIPATE ON FRIDAY
NIGHT AS UPPER LOW PULLS NORTHEAST AND ANY DAYTIME HEATING WANES.
EVEN BETTER DRYING APPEARS IN THE FORECAST SOUNDINGS IN ON FRIDAY
NIGHT AND SATURDAY...CONTINUING INTO SATURDAY NIGHT AS HIGH
PRESSURE REMAINS ACROSS THE AREA. GIVEN THE COLD AIR ADVECTION AS
850MB TEMPS FALL NEAR 10C WILL TREND HIGHS AND LOWS COOLER THAN
MAVMOS...WITH MOSTLY CLEAR NIGHTS AND A SUNNY SATURDAY.
SURFACE HIGH REMAINS IN CONTROL IN SUNDAY ACROSS THE OHIO
VALLEY...HOWEVER ALOFT A SHORT WAVE IS APPROACHING AND PUSHING
THROUGH INDIANA. SURFACE FLOW DOES NOT APPEAR TO OPEN AND ALLOW
FOR THE ADDITION OF GULF MOISTURE. THUS FOR NOW WILL HOLD OFF ON
POPS FOR SUNDAY UNTIL BETTER CONFIDENCE IS REVEALED IN LOWER LEVEL
MOISTURE....BUT WILL INCREASE CLOUD COVERAGE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 226 PM EDT THU AUG 9 2012
ENSEMBLES SUGGEST A FAIRLY PROGRESSIVE FLOW ACROSS THE NORTHERN
PARTS OF THE COUNTRY...WHILE THE SUB TROPICAL RIDGE HOLDS FROM THE
SOUTHERN ROCKIES EASTWARD ACROSS THE GULF COAST STATES. ANOTHER
UPPER DISTURBANCE IS EXPECTED TO DROP INTO THE GREAT LAKES AND OHIO
VALLEY EARLY NEXT WEEK...AND THEN LIFT OFF TO THE EAST BY THE MIDDLE
OF NEXT WEEK. ENSEMBLES SUGGEST THE BEST THREAT FOR PRECIPITATION
WITH THIS SYSTEM WILL BE MONDAY AND MONDAY NIGHT. WILL GO WITH
CHANCE POPS AT THOSE TIMES. HEIGHTS ARE EXPECTED TO RISE TOWARDS THE
MIDDLE OF NEXT WEEK AS TROUGH LIFTS OFF TO THE EAST...SO WILL
CONTINUE WITH A DRY FORECAST FOR TUESDAY AND WEDNESDAY.
BY THURSDAY...THERE ARE INDICATIONS THAT THE HEAT RIDGE MAY TRY TO
BUILD BACK INTO THE SOUTHERN PLAINS. THE ENSEMBLES SUGGEST ANOTHER
DISTURBANCE MAY RIDE OVER THE DEVELOPING RIDGE INTO THE LOCAL AREA
BY THURSDAY. WILL CONTINUE WITH CHANCE POPS AT THAT TIME.
&&
.AVIATION /DISCUSSION FOR THE 091800Z TAFS/...
ISSUED AT 1235 PM EDT THU AUG 9 2012
SOME LOW POTENTIAL FOR DISORGANIZED CONVECTION EXPECTED TO LINGER
THROUGH THE MID AFTERNOON HOURS OVER THE TAF SITES AS WARM ADVECTION
CONTINUES OVER A SURFACE BOUNDARY LOCATED SOUTH OF THE OHIO RIVER.
MOST OF THE STRONGER INSTABILITY HAS BEEN SWEPT OUT OF THE LOCAL
AREA DUE TO CONVECTION EARLY THIS MORNING...SO THERE IS SOME DOUBT
ABOUT HOW MUCH CONVECTION MAY REDEVELOP LATER THIS AFTERNOON.
APPEARS THE BEST CHANCES FOR CONVECTION WILL BE WITH A COLD
FRONT...WHICH WILL DROP SOUTHEAST ACROSS THE TAF SITES ROUGHLY IN
THE 092300Z-100400Z TIME FRAME. WILL CONCENTRATE THE THUNDER THREAT
DURING THESE TIMES IN THE FORECAST. BRIEF IFR VISIBILITY
RESTRICTIONS LIKELY IN THE HEAVIER CELLS. CONVECTIVE CLOUD BASES
030-040.
OUTSIDE OF ANY CONVECTION...CEILINGS ABOVE 050/SURFACE WINDS BELOW
12 KTS EXPECTED FOR THE MOST PART THROUGH 100600Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
331 PM EDT THU AUG 09 2012
.Short Term (Tonight through Friday Night)...
Issued at 331 PM EDT Thu Aug 9 2012
...Active Period of Weather Expected This Afternoon and Tonight...
Fairly active period of weather is shaping up for the Ohio Valley
this afternoon and tonight. In the near term, mid-level shortwave
combined with surface temperatures hitting convective temperatures
has resulted in convection firing across the region. Several areas
of convection are occurring across the area. The first is an
organizing line near the I-75 corridor in our eastern sections.
This is being forced by the aforementioned mid-level wave and by
diurnal heating. This activity will continue to head east and into
WFO JKL`s area over the next hour or so. Further west, a well
defined residual outflow boundary was located along our border with
WFO IND. This boundary extends from northern Dubois county NE to
Jefferson County. Convection is firing along this boundary due to
strong moisture convergence and diurnal heating. This activity
should head east-southeast over the next few hours. Finally
additional convection is firing also over west KY. Based on the
latest runs of the LMK WRF and 4km HRRR runs, this activity should
also head east-southeast and may impact our far southwestern
counties later this afternoon. Based on RUC proximity soundings,
this afternoon`s convective activity is likely to remain in the
pulse variety with damaging winds, torrential rains and intense CG
lightning being the main threats.
Latest deterministic and ensemble model runs seem to be showing some
forecast convergence with the forecast for later this evening and
overnight. First mid-level trough will scoot east this evening
while a secondary and more potent mid-level trough dropping down
into the Ohio Valley late tonight. As this wave drops south,
surface cyclone near KSTL will shift northeast while associated
surface cold drags behind. Strong mid-level height falls will
result in widespread synoptic scale lift across the region late
tonight. This combined with forcing along the front should result
in a secondary line of convection developing to our northwest and
slide southeast overnight. Despite this line moving through during
an instability minimum, the upper level dynamics appear to be strong
enough to support convection despite the meager instability.
Current thinking is that a convective line will generate along the
I-70 corridor and then drop southeast overnight. The line will
likely be strong to possibly severe especially to our northwest.
However, as the line heads southeast, it is possible that line may
weaken a bit as it slides through KY. Convection should be pushing
through southern Indiana in the 04-06Z time frame and then through
KY in the 06-11Z time frame. Have gone ahead and bumped up PoPs for
the overnight period. Lows will remain mild with temperatures
falling into the lower-mid 60s in the northwest and mid-upper 60s
elsewhere.
For Friday, the main forecast change here is that a lot more cloud
cover will be likely during the morning hours. Latest model
time-height model cross sections show plenty of low-level moisture
lingering behind the frontal boundary as it pushes through. Thus,
mostly cloudy skies seem very likely in the morning followed by
progressive clearing during the afternoon and into the evening
hours. Highs tomorrow will be quite cool compared to what we`ve
seen over the last few months. We should see readings in the upper
70s in the east with upper 70s to lower 80s in the central and
west. Lows Friday night will be quite comfortable with lows in the
mid-upper 50s.
.Long Term (Saturday through Thursday)...
Issued at 315 AM EDT Thu Aug 9 2012
...Mostly Sunny, Dry, and Cool Weekend Ahead...
A vertically stacked unseasonably far south and strong closed low
will begin to slowly fill over Lake Huron Saturday. This system will
slowly weaken and slowly lift north towards St. James Bay by late
Sunday. In its wake, it will leave residual troughing across the
western Great Lakes and the upper Midwest.
By early Saturday, the occluded front related to this upper low will
already have moved well east of the Commonwealth. Much drier and
cooler air originating in Canada, will have overspread the state by
dawn Saturday.
Expect mostly clear skies and relatively cool temperatures for the
upcoming weekend. Dewpoints will likely fall into the lower 50s by
Saturday afternoon. Highs will struggle to exceed 80 on Saturday
with highs on Sunday warming just a few degrees into the lower 80s.
Overnight lows early Sunday will quite likely reach into the upper
50s, with perhaps our urban areas remaining near 60.
A broad longwave trough will remain centered roughly over the Great
Lakes during the early portion of next week. This will ensure no
repeat of the excessively hot temperatures of early August anytime
soon. Both the latest GFS and the ECMWF show a disturbance sliding
southeast towards the base of this longwave trough Monday and
Tuesday. This system will approach the Commonwealth by late Monday.
At the surface, this system will likely aid in the formation of a
weak surface trough that may serve as a focus for convection
beginning late Monday, possibly continuing through the bulk of
Tuesday. Will introduce a chance of storms for the later half of
Monday, extending through Tuesday.
Temperatures will warm a bit within the Monday through Thursday time
period. However, even by Wednesday through Friday, temperatures
will not exceed our seasonal mid-August averages with highs
remaining in the upper 80s to around 90
&&
.Aviation (18Z TAF issuance)...
Issued at 117 PM EDT Thu Aug 9 2012
Approaching mid-level wave combined with surface heating has led to
the development of scattered convection in the I-65 corridor of
central Kentucky. Activity appears to be developing along a
residual northward moving outflow boundary. Expect scattered
convection to continue developing across the region this afternoon.
Initially, best coverage will be across north-central Kentucky, but
as the area approaches the convective temperature, we should see
convection gradually fill in. In general, VFR conditions are very
likely outside any thunderstorms. If a storm impacts a terminal, a
reduction in cigs and visibilities down to possibly tempo IFR will
be possible.
More organized convection is forecast to occur later this afternoon
and evening as a secondary mid-level wave and associated surface
cold front push through the region. These storms may pack a punch
as they move through with torrential rainfall, gusty winds, and
frequent lightning. Timing from the previous forecast still looks
rather good with KBWG being impacted from 10/06-11Z, KSDF from
10/04-08Z and KLEX from about 10/08-12Z. Latest model progs show
low-level moisture remaining in the region toward dawn with MVFR
visibilities and near IFR/MVFR cigs. Low clouds will likely persist
through the morning hours on Friday with improvement likely holding
off until after 10/18Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......MJ
Long Term........JSD
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
136 PM EDT THU AUG 9 2012
.SYNOPSIS...
ISSUED AT 321 AM EDT THU AUG 9 2012
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL BRING RAIN AND UNSEASONABLY
COOL WEATHER TODAY THROUGH FRIDAY. HIGH TEMPERATURES WILL ONLY REACH
THE MID 60S TO MID 70S TODAY AND FRIDAY. IT WILL ALSO BECOME RATHER
BREEZY LATE TONIGHT THROUGH FRIDAY. A FEW LIGHTER SHOWERS MAY LINGER
INTO SATURDAY BUT MOST OF THE WEEKEND SHOULD BE DRY.
&&
.UPDATE...
ISSUED AT 750 AM EDT THU AUG 9 2012
I UPDATED THE GRIDS TO TRACK THE AREA OF CONVECTION NEAR JACKSON
OUT AN BRING THE AREA OF RAIN NORTH OF MKG IN. I KEPT KEPT THE
TREAT OF THUNDERSTORMS THIS AFTERNOON DUE TO THE STRENGTH OF THE
DYNAMICS WITH THIS DIGGING SYSTEM AND THE DEVELOPING MID LEVEL JET
SEGMENT SHOWN BY THE LATEST RAP (09Z) OVER CENTRAL LOWER MICHIGAN
AFTER 18Z CAUSING COUPLING WITH THE EXIT REGION OF THE JET
SEGMENT DIVING INTO IL AT THAT TIME. THIS SHOULD HELP PULL MID
LEVEL UNSTABLE AIR NORTH OVER THE EASTERN CWA LATE THIS AFTERNOON.
THE HEAVY RAIN THREAT WILL HAVE TO BE WATCHED... I COULD SEE A NEED
FOR URBAN AND SMALL STREAM FLOODING ADVISORIES BY THIS EVENING AS
THE RAIN BAND COMES TOGETHER OVER OUR CWA.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON)
ISSUED AT 321 AM EDT THU AUG 9 2012
AN UPPER LEVEL LOW PRESSURE SYSTEM IN CONJUNCTION WITH AN
INTENSIFYING SFC LOW TRACKING NE ACROSS OHIO TONIGHT WILL BRING RAIN
AND UNSEASONABLY COOL CONDITIONS TODAY THROUGH FRIDAY. MAX TEMPS
TODAY WILL ONLY REACH THE UPPER 60S TO MID 70S. IT WILL BE EVEN
COOLER FRIDAY WITH STRONG NORTH WINDS... EXTENSIVE LOW CLOUDS AND
SHOWERS. MAX TEMPS FRIDAY WILL ONLY REACH THE MID 60S TO NEAR 70.
MAINTAINING VERY HIGH (CATEGORICAL) POPS FOR RAIN TODAY THROUGH
TONIGHT. LOCALLY HEAVY RAIN IS POSSIBLE WITH DEEP MOISTURE IN PLACE
AND HIGH PRECIPITABLE WATER VALUES. ON AVERAGE A GENERAL ONE TO TWO
INCH TYPE RAINFALL IS LIKELY FOR MOST OF OUR FCST AREA FROM TODAY
THROUGH FRIDAY BUT A FEW HIGHER TOTALS ARE POSSIBLE. MOST (IF NOT
ALL) CONVECTIVE DEVELOPMENT TODAY THROUGH TONIGHT SHOULD STAY SOUTH
OF OUR FCST AREA ACROSS IN/OH WHERE SOME DECENT SFC/ELEVATED
INSTABILITY WILL DEVELOP LATER TODAY THROUGH TONIGHT.
EXTENSIVE CLOUD COVER WILL LIKELY LINGER ON SATURDAY BUT ANY
LINGERING LIGHTER SHOWERS SHOULD GRADUALLY TAPER OFF AS THE UPPER
TROF AXIS SHIFTS A LITLE FURTHER ENE AWAY FROM OUR REGION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 321 AM EDT THU AUG 9 2012
THERE WILL BE SLOW WARMING TREND UNTIL THE NEXT SYSTEM COMES THROUGH
LATE IN THE WEEK. COULD BE AN ACTIVE THUNDERSTORM EVENT LATE WEEK
WITH THE FRONT.
THE MODELS DO AGREE OVER ALL ON THE LARGE SCALE UPPER WAVE PATTERN.
THAT IS THE SOUTHERN BRANCH OF THE POLAR JET SLOWLY DIGS SOUTH OVER
THE WESTERN CONUS THROUGH AT LEAST WEDNESDAY. THAT IN TURN RESULTS
IN RISING HEIGHTS OVER THE CENTRAL CONUS INTO MID WEEK. THIS ALL
HAPPENS DUE TO THE STORM SYSTEM THAT IS CURRENTLY NEAR THE NORTH
POLE DIGGING SOUTH SOUTHEAST INTO WESTERN AND CENTRAL CANADA DURING
THIS SAME TIME(SUNDAY INTO WEDNESDAY). THAT RESULTS IN THE LARGE
UPPER HIGH THAT HAS BEEN CAUSING ALL THE HOT WEATHER FOR THE PAST
FEW MONTHS... OVER MOST OF THE CONUS... TO FINALLY BE SQUASHED AND
SHIFTED TO THE GULF OF MEXICO BY WEDNESDAY. THE RISING HEIGHTS WOULD
MEAN WARMER TEMPERATURES HEAR AGAIN (BUT JUST FOR A SHORT TIME).
AS I WROTE YESTERDAY THROUGH... LARGE SCALE CHANGES IN THE PLANETARY
WAVE PATTERN ARE CURRENTLY UNDERWAY. I DO NOT EXPECT ANOTHER BIG
HEAT WAVE FROM THIS WARM UP. A STRONG COLD FRONT FOLLOWS LATE IN THE
WEEK. THAT WILL BE PROCEEDED BY THUNDERSTORMS. HOWEVER THAT WILL BE
JUST BEYOND OUR CURRENT FORECAST PERIOD. THE EVENT LATE WEEK COULD
BE A SIGNIFICANT STORM EVENT FROM WHAT BOTH THE GFS AND ECMWF
SUGGEST. REMEMBER WE HAVE A POLAR LOW DIGGING SOUTH THAT MAY PHASE
WITH PACIFIC STORM IN THAT TIME FRAME.
AS FOR THE DAY TO DAY...OUR CLOSED UPPER LOW SHOULD BE DEPARTING THE
WESTERN GREAT LAKES SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE WILL
BRING SUNSHINE AND TYPICAL MID AUGUST TEMPERATURES. A WEAK SYSTEM
WILL MOVE THROUGH THE WESTERN GREAT LAKES IN THE MONDAY TIME FRAME.
THAT SYSTEM IS CURRENTLY MOVING ON SHORE OVER THE WESTERN CONUS AND
IS THE KICKER THAT HELPS TO BOOT THE UPPER LOW OUT OF THE GREAT
LAKES. THE MODELS ARE STRUGGLING WITH IT BUT NO MATTER... IT IS WEAK
SYSTEM AND SHOULD HAVE A LIMITED IMPACT TO SOUTHWEST MICHIGAN
WEATHER IN THE MONDAY TIME FRAME...ISOLATED SHOWERS AT BEST.
THE REAL WARM UP WILL BE TUESDAY AND WEDNESDAY. STORMS WILL
FOLLOW... OF COURSE THERE IS ALWAYS TIMING ISSUES WITH SUCH FRONTS
BUT WE WILL HAVE TO WATCH THIS ONE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 136 PM EDT THU AUG 9 2012
NOT MUCH CHANGE TO THE FORECAST. UPPER LOW WILL CONTINUE TO MOVE
TOWARD LOWER MICHIGAN RESULTING IN SHOWERS AND LOWER CIGS. NE WIND
FLOW WILL ADVECT ADDITIONAL LOW LEVEL MOISTURE SWWD WHICH WILL
LEAD TO SOME IFR CIGS. CIGS WON/T ALWAYS BE IFR AND VSBYS WILL BE
P6SM AT TIMES. BOTH WILL BOUNCE UP AND DOWN THROUGH THE NEXT 24
HRS. THE UPPER LOW WILL BE SLOW TO MOVE ACROSS THE AREA.
&&
.MARINE...
ISSUED AT 321 AM EDT THU AUG 9 2012
WINDS AND WAVES WILL RAMP UP SIGNIFICANTLY TONIGHT THROUGH FRIDAY.
WATERSPOUTS ARE ALSO POSSIBLE BY THIS AFTERNOON THROUGH TONIGHT INTO
FRIDAY.
&&
.HYDROLOGY...
ISSUED AT 321 AM EDT THU AUG 9 2012
CUMULATIVE RAINFALL TOTALS FROM TODAY THROUGH FRIDAY OF AN INCH OR
TWO ARE LIKELY ACROSS MUCH OF OUR FCST AREA. NO SIGNIFICANT HYDRO
ISSUES ARE ANTICIPATED THOUGH GIVEN LOW RIVER LEVES/DRY ANTECEDENT
CONDITIONS ALTHOUGH RIVER LEVELS WILL COME UP SOMEWHAT IN RESPONSE
TO THIS PROLONGED RAIN EVENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WATCH FROM FRIDAY MORNING THROUGH SATURDAY MORNING FOR
LMZ844>849.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT FRIDAY
FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...93
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
305 PM CDT THU AUG 9 2012
.DISCUSSION...
TEMPERATURES WILL PROVIDE THE PRIMARY FORECAST CHALLENGES THROUGH
FRIDAY NIGHT...THEN ATTENTION SHIFTS MORE TOWARD PRECIPITATION
CHANCES OVER THE WEEKEND.
MAIN FEATURES FROM THE 12Z UPPER AIR CHARTS THIS MORNING SHOWED THE
FOLLOWING. AT 300 MB...JETSTREAM CURVED NORTHEAST ACROSS THE PACIFIC
NORTHWEST INTO THE NORTHERN PLAINS...THEN TURNED SOUTHEAST INTO THE
OHIO VALLEY. A JET MAX OF AROUND 100 KNOTS WAS NOTED OVER MINNESOTA.
AT 500 MB...A RATHER IMPRESSIVE CLOSED LOW WAS OVER NORTHEAST
MINNESOTA WITH 12 HOUR HEIGHT FALLS OF 70 METERS NOTED AT KINL. THE
CENTER OF A MID LEVEL RIDGE WAS OVER THE FOUR CORNERS REGION.
COOLER AIR WAS PUSHING DOWN FROM MINNESOTA AND THE EASTERN DAKOTAS
AT 700 MB AND 850 MB.
SURFACE ANALYSIS EARLY THIS AFTERNOON INDICATED A RIDGE OF COOL HIGH
PRESSURE EXTENDING FROM ONTARIO AND MANITOBA DOWN INTO THE NORTHERN
AND WESTERN PLAINS. WINDS WERE MAINLY FROM THE NORTH OVER THE LOCAL
AREA. THAT SURFACE RIDGE WILL BUILD EASTWARD ACROSS THE FORECAST
AREA TONIGHT THROUGH FRIDAY NIGHT...WITH SEASONABLE TEMPERATURES AND
DRY CONDITIONS. EXPECT SOME PATCHY FOG TONIGHT AS WINDS DECREASE...
ESPECIALLY IN PARTS OF OUR CENTRAL AND EASTERN ZONES WHERE SPOTTY
RAIN FELL YESTERDAY AND TUESDAY. EXPECT THAT TO BURN OFF QUICKLY
FRIDAY...IF IT DEVELOPS...WITH SCATTERED CUMULUS MOST AREAS BY THE
AFTERNOON. HIGHS FRIDAY WILL BE IN THE 80S...CLOSE TO NAM MOS.
RETURN FLOW STRENGTHENS LATE FRIDAY NIGHT INTO SATURDAY AND
MODELS ARE IN GENERAL AGREEMENT WITH LARGE SCALE PATTERN. THEY
SHOW SOME 850-700 MB THETA E ADVECTION SPREADING FROM WEST TO EAST
ON SATURDAY. LARGE SCALE FORCING SEEMS WEAK AT BEST...SO KEPT POPS
ONLY AT 20 PERCENT AND TRIED TO CONFINE THOSE TO NORTHEAST
NEBRASKA SATURDAY. A MODEST SHORTWAVE TROUGH DOES MOVE ACROSS THE
PLAINS FOR SATURDAY NIGHT/EARLY SUNDAY...AND THIS IS PROBABLY OUR
BEST CHANCE FOR THUNDERSTORMS. THE 12Z GFS SEEMED WAY TOO GENEROUS
WITH QPF AND ITS OUTPUT WAS GENERALLY NOT USED. FAVORED A BLEND OF
THE NAM AND ECMWF FOR NOW...BUT SHOULD BE ABLE TO ADJUST THINGS
MORE AS WE GET CLOSER WITH 4 KM NAM AND HRRR MODELS. LINGERED SOME
LOW POPS INTO SUNDAY BASED ON CURRENT MODEL TIMING OF FORCING.
OTHERWISE...LOOK FOR DEAMPLIFICATION OF THE 500 MB PATTERN THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK AS RIDGE SHIFTS FROM THE FOUR
CORNERS REGION TO THE SOUTHERN PLAINS. AS HEIGHTS INCREASE BY MID
WEEK...HIGHS IN THE 90S WILL BECOME COMMON AGAIN.
MILLER
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
THE PRIMARY CONCERN FOR THIS TAF PACKAGE ARE THE NORTHWEST THRU
NORTHEAST WINDS. A WEATHER SYSTEM OVER THE UPPER GREAT LAKES INTO
MINNESOTA WILL DROP SOUTHEAST INTO THE LOWER GREAT LAKES AND OHIO
VALLEY. SOME STRONGER WINDS ALOFT WILL MIX DOWN THIS AFTERNOON.
THE TRACK OF THIS SYSTEM SHOULD KEEP THE ACTIVE WEATHER TO THE
EAST OF THE TAF SITES. SURFACE WINDS WILL RANGE FROM 10 TO 18KTS
SUSTAINED WITH GUSTS TO 22KTS. CUMULUS THIS AFTERNOON SHOULD GIVE
WAY TO DECREASING CLOUDS AFTER SUNSET. THE SURFACE WINDS WILL
DIMINISH TO 5KTS OR LESS THIS EVENING AS SURFACE HIGH PRESSURE
BUILDS IN.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
138 PM EDT THU AUG 9 2012
.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA TODAY. A STRONG
SURFACE COLD FRONT WILL APPROACH OUR REGION FROM THE NORTHWEST
FRIDAY AND CROSS CENTRAL NC ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM THURSDAY...
A SMALL AREA OF STRATUS OVER WILSON...NASH AND EDGECOMBE COUNTIES IS
ERODING AND DRIFTING NORTHEAST AND WILL GIVE WAY TO MOSTLY CLEAR
SKIES OVER THE COASTAL PLAIN THIS MORNING. HOWEVER...SOME THIN HIGH
CLOUDS OUT AHEAD OF CONVECTION OVER NORTHERN MS/AL WILL OVERSPREAD
THE AREA FROM THE WEST...AND SHOULD BECOME THICKER OVER THE WESTERN
PIEDMONT LATER TODAY AS THE SHORTWAVE RESPONSIBLE FOR THE CONVECTION
SWINGS INTO THE SOUTHEAST US. TEMPS WILL BE MOSTLY UNAFFECTED BY
THE CLOUDS...HOWEVER. THE 12Z KGSO RAOB CAME IN WITH A LOW LEVEL
THICKNESS OF 1414M... A GOOD 5M HIGHER THAN FORECAST. ADDING A
COUPLE DEGREES ONTO HIGHS DERIVED FROM 1414M YIELDS 90-93...WHICH IS
IN LINE WITH STATISTICAL GUIDANCE AND THE CURRENT FORECAST.
MODIFIED 12Z RAOBS AND MODEL FORECASTS SHOW 1500-2000 J/KG OF MLCAPE
THIS AFTERNOON...GREATEST FROM THE COASTAL PLAIN TO THE SOUTHERN
PIEDMONT. WEAK LOW LEVEL FORCING...ALONG WITH MUCH DRIER MID LEVEL
AIR THAN THE PAST FEW DAYS...SHOULD LIMIT COVERAGE OF CONVECTION TO
MOSTLY ISOLATED STORMS. THERE IS A SMALL HINT OF A WEAK SURFACE
OVER THE WESTERN PIEDMONT...AND THE MORNING RUNS OF THE HRRR HAS
BEEN CONSISTENTLY SHOWING CONVECTION INVITATION FROM ANSON COUNTY TO
RANDOLPH COUNTY JUST AFTER 18Z. ANY STRONGER STORMS THAT DEVELOP
WILL HAVE PLENTY OF DRY AIR TO ENTRAIN...AS WELL AS A WETBULB
FREEZING LEVEL BELOW 10K FT...SO AN ISOLATED WIND/HAIL THREAT WILL
EXIST. -SMITH
TONIGHT...DECENT MID LEVEL TROUGH CURRENTLY OVER THE MO/ARK OZARKS
PROJECTED TO ADVANCE EWD AND WILL APPROACH OUR REGION AFTER SUNSET.
THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS FEATURE AND
CONFIDENCE INCREASING THAT WE WILL LIKELY SEE AT LEAST SCATTERED
CONVECTION EITHER MOVE INTO OR DEVELOPMENT OVER THE WESTERN PIEDMONT
AFTER MIDNIGHT. HAVE INCREASED POPS SLIGHTLY IN THE FAR WEST TO 40
PERCENT. IF MODEL GUIDANCE REMAINS CONSISTENT....COULD ARGUE FOR A
MENTION OF LIKELY THOUGH LOW LEVEL ATMOSPHERE WILL ACHIEVE MAXIMUM
STABILITY DURING THIS PERIOD. MIN TEMPS UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 315 AM THURSDAY...
FRIDAY...CONVECTIVELY ACTIVE DAY POSSIBLE ACROSS CENTRAL NC THOUGH
STILL SOME QUESTION AS THE AMOUNT OF INSTABILITY AND SHEAR THAT WILL
BE ATTAINED.
AFOREMENTIONED MID LEVEL TROUGH WILL SLOW ITS EWD ADVANCE...WAITING
FOR ENERGY ROTATING AROUND THE DEEPENING UPPER LEVEL TROUGH OVER THE
GREAT LAKES TO ROUND THE BASE OF THE TROUGH. THIS LEAD TROUGH WILL
LIKELY MAINTAIN CONSIDERABLE CLOUDINESS IN THE MORNING ALONG WITH
SCATTERED TO NUMEROUS SHOWERS AND A FEW T-STORMS. AS THE ENERGY IN
THE GREAT LAKES TROUGH GETS CLOSER TO THE APPALACHIANS AND MID
ATLANTIC...SHOULD SEE AN INCREASE IN THE 850-700MB WIND FIELD
LEADING TO BETTER BULK SHEAR (AROUND 30 KTS) SUGGESTING BETTER
POTENTIAL FOR ORGANIZED CONVECTION. DUE TO DEEP UNIDIRECTIONAL
FLOW...EXPECT MAINLY MULTICELLULAR LINEAR CONVECTION WITH POTENTIAL
FOR DAMAGING WIND GUSTS AND SOME HAIL. TIMING FAVORS LATE FRIDAY
INTO FRIDAY EVENING...AND MAINLY ALONG AND EAST OF HIGHWAY 1 WHERE
BETTER LOW LEVEL INSTABILITY WILL LIE.
TEMPS FRIDAY DEPENDENT ON AMOUNT OF INSOLATION. EXPECT A PERIOD OF
PARTIAL SUN IN THE AFTERNOON PRIOR TO CONVECTION BECOMING MORE
ACTIVE. THICKNESSES IN THE LOWER 1420S SUPPORT MAX TEMPS IN THE 80S
TO NEAR 90.
FRIDAY NIGHT...EXPECT ACTIVE CONVECTION TO PERSIST THROUGH THE NIGHT
AS TROUGH BECOMES ELONGATED DUE TO APPROACH OF GREAT LAKES SYSTEM.
DEEPENING SW FLOW WILL LIKELY CAUSE CONVECTIVE BANDS TO TRAIN NEWD.
THUS...SHOULD SEE WEATHER SCENARIO TRANSITION FROM A SEVERE WEATHER
THREAT IN THE EARLY EVENING TO A HEAVY RAIN THREAT THAT WILL PERSIST
INTO EARLY SATURDAY. WILL CONTINUE LIKELY POPS FOR NOW. MIN TEMPS
UPPER 60S TO LOWER 70S. -WSS
SATURDAY AND SATURDAY NIGHT:
THE SURFACE COLD FRONT IS EXPECTED TO SLOWLY MOVE ACROSS CENTRAL NC
ON SATURDAY... BEFORE STALLING AND DISSIPATING ACROSS THE COASTAL
PLAIN OR JUST TO THE SOUTH AND EAST OF THE AREA SATURDAY NIGHT INTO
SUNDAY. HAVE FOLLOWED CLOSER TO A BLEND OF THE GFS AND ECWMF WRT THE
FRONTAL TIMING AS HPC CONTINUES TO NOTE THE NAM APPEARS TO BE A SLOW
OUTLIER. THIS WILL LEAD TO ANOTHER GOOD CHANCE OF SHOWERS AND STORMS
FOR AT LEAST EASTERN AND SOUTH/SOUTHEASTERN PORTIONS OF THE AREA.
HAVE INCREASED POPS ACROSS THE EASTERN AND SOUTH/SOUTHEASTERN
PORTIONS OF THE AREA FOR SATURDAY... GIVEN A BIT SLOWER TIMING OF
THE FRONT. THIS YIELDS LIKELY POPS EAST/SOUTHEAST TO SLIGHT CHANCE
NORTHWEST. WITH THE SURFACE FRONT DRAPED ACROSS THE AREA A GOOD PART
OF THE DAY THIS WILL CREATE A TRICKY HIGH TEMP FORECAST ALONG WITH
HOW MUCH INSTABILITY WILL BE PRESENT (HOW MUCH HEATING WILL WE BE
ABLE TO REALIZE WITH THE PARTLY SUNNY TO MOSTLY CLOUDY SKIES) AND
RESULTANT SEVERE STORM CHANCES. THE GFS IS SHOWING 1000 TO 1500 J/KG
OF MLCAPE FOR SATURDAY AFTERNOON GENERALLY ALONG AND EAST OF U.S.
HIGHWAY 1. THIS COMBINED WITH CONTINUED LARGE SCALE LIFT AND DEEP
LAYER SHEAR ON THE ORDER OF 30 TO 35 KTS SHOULD LEAD TO AT LEAST
SOME ORGANIZED CONVECTION ACROSS EASTERN PORTIONS OF THE AREA...
WITH THE MAIN SEVERE THREAT FROM DAMAGING WINDS. IN ADDITION TO THE
THREAT FOR SEVERE STORMS... THE STRONGEST STORMS WILL LIKELY PRODUCE
HEAVY RAIN AS PW`S ARE EXPECTED TO CONTINUE TO BE AROUND 2 INCHES
ACROSS THE EAST AND SOUTH/SOUTHEAST. THIS MAY LEAD TO A FLASH
FLOODING THREAT WITH THE POTENTIAL OF THE SLOW MOVING FRONT...
ESPECIALLY ACROSS URBAN AREAS. WILL ADD MENTION OF SEVERE STORMS AND
FLASH FLOODING TO THE HWO FOR THIS TIMEFRAME.
WILL TREND POPS DOWNWARD SATURDAY NIGHT AS THE CLOSED LOW ALOFT OVER
THE GREAT LAKES BEGINS TO LIFT NORTH-NORTHEASTWARD ALLOWING THE MAIN
MID LEVEL TROUGH AXIS TO SWING THROUGH THE AREA. THIS WILL YIELD NO
POPS NW TO SLIGHT CHANCE/CHANCE EAST/SOUTHEAST. AS MENTIONED
ABOVE... HIGH TEMPS WILL BE TRICKY FOR SATURDAY. FOR NOW WILL KEEP
HIGHS IN THE MID TO UPPER 80S ACROSS THE AREA. LOW TEMPS ON SUNDAY
MORNING ARE EXPECTED TO RANGE FROM THE MID 60S NW TO AROUND 70 SE.
-BSD
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 315 AM THURSDAY...
THE COLD FRONT MENTIONED IN THE SHORT TERM DISCUSSION ABOVE IS
EXPECTED TO CONTINUE TO DISSIPATE/WASH OUT ON SUNDAY JUST TO THE
EAST AND SOUTHEAST OF THE AREA AS THE MID/UPPER FLOW BECOMES MORE
ZONAL IN THE WAKE OF THE DEPARTED MID/UPPER TROUGH ALOFT. THIS WILL
RESULTED IN GENERALLY DRY CONDITIONS... WITH ONLY SLIGHT CHANCES FOR
SHOWERS AND STORMS ON SUNDAY AND MONDAY. UNCERTAINTY GROWS WRT THE
STRENGTH AND TIMING OF A MUCH WEAKER S/W TROUGH ALOFT AND MOISTURE
RETURN FOR MONDAY NIGHT THROUGH TUESDAY NIGHT. FOR NOW WILL SHOW A
SLIGHT CHANCE OF DIURNAL SHOWERS AND STORMS FOR THIS TIMEFRAME. THE
WEAK S/W TROUGH ALOFT IS EXPECTED TO BE EAST OF THE AREA BY
WEDNESDAY WITH RIDING ALOFT BUILDING BACK INTO THE AREA... YIELDING
LESS OF A CHANCE OF AFTERNOON AND EVENING STORMS. TEMPS DURING THE
PERIOD ARE EXPECTED TO BE IN THE MID TO UPPER 80S... WITH PERHAPS A
RETURN TO SOME LOCATIONS REACHING THE LOWER 90S AGAIN BY EARLY TO
MID NEXT WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 135 PM THURSDAY...
THIS MORNING`S IFR/LIFR CONDITIONS HAVE DISSIPATED. SCATTERED CLOUDS
BASED BELOW 3 THOUSAND FT AGL DO PERSIST... BUT THIS WILL CONTINUE
TO LIFT AND DISSIPATE. CONVECTIVE CLOUDS WILL DEVELOP AND PERSIST
ALONG WITH HIGH THIN CLOUDS... BUT VFR CONDITIONS WILL HOLD FOR THE
REST OF THIS AFTERNOON... WITH A LIGHT WIND MAINLY FROM THE S OR SW.
AFTER 22Z... THE APPROACH OF A POTENT MID LEVEL LOW PRESSURE TROUGH
WILL BRING INCREASING COVERAGE OF SHOWERS AND STORMS FROM WEST TO
EAST... LIKELY AFFECTING INT/GSO AFTER 23Z... RDU AFTER 01Z... AND
RWI/FAY (WITH LESSER AREAL COVERAGE) AFTER 03Z. MVFR CONDITIONS ARE
LIKELY IN AND NEAR STORMS WITH BRIEF GUSTY WINDS. THE PERIOD OF
STORMY CONDITIONS IS LIKELY TO LAST FOR 2-4 HOURS AT ANY GIVEN
FORECAST SITE. SCATTERED SHOWERS MAY PERSIST AFTER 07Z TONIGHT BUT
WILL BE LOW IN COVERAGE. SCATTERED CLOUDS BASED AT 1-3 THOUSAND FT
AGL ARE EXPECTED 08Z-13Z WITH MVFR VSBYS POSSIBLE. RAPIDLY
INCREASING DEEP MOISTURE THROUGH THE COLUMN COMBINED WITH THE
APPROACHING LOW PRESSURE TROUGH ALOFT WILL FORCE AN EARLY
DEVELOPMENT OF SCATTERED TO NUMEROUS SHOWERS/STORMS BY LATE FRIDAY
MORNING... AS EARLY AS 15Z.
LOOKING BEYOND 18Z FRIDAY... EXPECT ONGOING NUMEROUS STORMS THROUGH
THE AFTERNOON WITH A HIGH PROBABILITY OF BRIEF MVFR CIGS/VSBYS IN
AND NEAR THESE STORMS. STORMS SHOULD SLOWLY WEAKEN AND BECOME
SCATTERED TO ISOLATED BY LATE FRIDAY EVENING... THEN INCREASE ANEW
BY LATE SATURDAY MORNING AS A COLD FRONT SLOWLY MOVES IN FROM THE
WEST. MVFR CONDITIONS ARE POSSIBLE THROUGH SATURDAY NIGHT... BUT THE
ARRIVAL OF DRIER AIR WILL BRING A TREND TO PREVAILING VFR CONDITIONS
SUNDAY MORNING. NO SIGNIFICANT PERIODS OF ADVERSE AVIATION
CONDITIONS ARE ANTICIPATED FROM MIDDAY SUNDAY THROUGH TUESDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS/BSD
LONG TERM...BSD
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
109 PM CDT THU AUG 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY
241 AM CDT THU AUG 9 2012
MAIN CONCERNS INCLUDE RAIN CHANCES TODAY INTO THIS EVENING/FOG FRIDAY
NIGHT/TEMPERATURES THROUGH THE PERIOD.
LATEST WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWING A MID-LEVEL
SHORTWAVE TROUGH MOVING SOUTHEAST ACROSS SOUTHERN WI/EASTERN IA.
ANOTHER MORE VIGOROUS SHORTWAVE WAS MOVING SOUTH THROUGH WESTERN
ONTARIO/ARROWHEAD REGION OF MN. SOUTHERN SHORTWAVE TROUGH
DEFORMATION AREA WAS PRODUCING SOME 700MB FRONTOGENETIC FORCING AND
RESULTING IN SCATTERED -SHRA ACTIVITY MAINLY EAST OF THE MISSISSIPPI
RIVER. RAP SHOWS THIS FRONTOGENESIS WEAKENING OVER THE NEXT FEW
HOURS...AND RADAR MOSAIC ALREADY SHOWING DISSIPATION OF THE SHRA
ACTIVITY. MEANWHILE...THE TROUGH DROPPING SOUTH THROUGH
ONTARIO/NORTHERN MN WAS PRODUCING A MORE ORGANIZED BAND OF
SHRA/ISOLD THUNDER IN GOOD 700-300MB PV-ADVECTION PER THE RAP.
OTHERWISE...SKIES ACROSS THE AREA WERE MOSTLY CLOUDY WITH
TEMPERATURES IN THE 60S.
LATEST NCEP MODELS/SREF REMAIN IN GOOD AGREEMENT THROUGH THE SHORT
TERM PERIOD.
FOR TODAY...WILL BE WATCHING THE WAVE OVER ONTARIO/NORTHERN MN DROP
SOUTHEAST ACROSS THE AREA. INCREASING PV-ADVECTION/STEEPENING LAPSE
RATES ACROSS THE AREA WILL LEAD TO MORE SHOWER/THUNDER DEVELOPMENT.
BEST FORCING APPEARS TO BE EAST OF THE MISSISSIPPI...SO TRENDED POPS
HIGHER THERE. IN ADDITION...THE NAM INDICATING 0-3KM MUCAPE
INCREASING INTO THE 1000-1500J/KG RANGE BY NOON WITH BULK SHEAR IN THE
15 TO 30KT RANGE FOR PERHAPS SOME LINEAR ORGANIZATION OF THE
CONVECTION. WITH THIS IN MIND...ALONG WITH COLDER AIR ALOFT AND
LOWERING WET BULB ZERO HEIGHTS...WILL HAVE TO WATCH FOR ISOLATED
SEVERE THREAT TODAY WITH HAIL AND WIND BEING THE MAIN THREATS.
OTHERWISE...TEMPERATURES WILL BE A BIT COOLER WITH THE
TROUGH/SCATTERED CONVECTION. ANTICIPATING HIGHS TODAY RANGING FROM
THE UPPER 60S ACROSS NORTH CENTRAL WI...TO THE LOWER/MID 70S
ELSEWHERE.
LOOK FOR THE TROUGH TO DEEPEN/FORM A CLOSED LOW AS IT MOVES
SOUTHEAST OF THE AREA TONIGHT TOWARD IN/MI BORDER BY FRI 12Z. AT THE
SURFACE...HIGH PRESSURE WILL BE BUILDING INTO THE AREA WITH
DRYING/NORTHERLY FLOW. THIS IS EXPECTED TO DRY UP/PUSH ANY LINGERING
SHRA ACTIVITY SOUTHEAST OF THE AREA BY MIDNIGHT...WITH CLEARING
SKIES FROM NORTHWEST TO SOUTHEAST. LOOK FOR LOWS IN THE LOWER/MID
50S WITH POCKETS OF MID/UPPER 40S IN THE CRANBERRY BOG AREAS OF
CENTRAL WI.
ON FRIDAY...CLOSED MID-LEVEL AND DEEP SURFACE LOW WILL HANG UP OVER
SOUTHERN LOWER MI AS HIGH PRESSURE CONTINUES TO BUILD INTO OUR AREA.
DECENT DRYING NORTHERLY FLOW WILL RESULT ACROSS THE AREA. MAY SEE
SOME CUMULUS BUILD UP ACROSS THE EASTERN PORTION OF THE AREA DUE TO
CLOSER PROXIMITY OF COLDER/CYCLONIC FLOW ALOFT. TRENDED DEW POINTS
LOWER DUE TO ANTICIPATED DEEPER MIXING TO 825MB PER THE NAM BUFKIT
SOUNDING. HIGH TEMPERATURES WILL CONTINUE TO BE A BIT ON THE COOLER
THAN NORMAL SIDE IN THE 70S.
HIGH PRESSURE WILL SETTLE OVERHEAD FRIDAY NIGHT WITH THE RIDGE AXIS
OVER AT LEAST THE WESTERN HALF OF THE FORECAST AREA. LIGHT
WINDS/CLEAR SKIES AND WATER TEMPERATURES SITTING IN THE UPPER 70S
WILL LIKELY LEAD TO SOME RIVER VALLEY FOG TOWARD MORNING.
OTHERWISE...OVERNIGHT LOWS WILL BE QUITE COOL IN THE 40S. HIGH
PRESSURE CONTINUES TO BE IN CONTROL ACROSS THE AREA THROUGH SATURDAY
FOR DRY CONDITION WITH HIGHS IN THE MID/UPPER 70S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
241 AM CDT THU AUG 9 2012
LATEST GFS/ECMWF I FAIRLY DECENT AGREEMENT THROUGH THE EXTENDED
FORECAST PERIOD. BOTH SHOW A WEAK MID-LEVEL TROUGH MOVING EAST OUT
OF THE DAKOTAS/CENTRAL PLAINS TOWARD THE AREA SATURDAY NIGHT THROUGH
SUNDAY NIGHT FOR A SMALL CHANCE OF SHOWER/THUNDERSTORMS. A MORE
SIGNIFICANT LOW PRESSURE SYSTEM IS SLATED TO MOVE EAST OUT OF THE
PACIFIC NORTHWEST INTO THE REGION BY WEDNESDAY. WARM AIR ADVECTION
IN ADVANCE OF THIS SYSTEM WILL GIVE THE AREA INCREASING
SHOWER/THUNDERSTORM CHANCES FROM TUESDAY INTO WEDNESDAY.
OTHERWISE...LOOK FOR TEMPERATURES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL IN THE EXTENDED WITH HIGHS WARMING FROM THE 70S ON SUNDAY TO
WELL INTO THE 80S TUESDAY AND WEDNESDAY.
&&
.AVIATION...THROUGH 18Z FRIDAY
109 PM CDT THU AUG 9 2012
FORECAST CONCERNS THIS PERIOD ARE PRECIPITATION CHANCES THIS
AFTERNOON...THEN STRATUS/FOG POTENTIAL OVERNIGHT. CLOSED UPPER
LEVEL LOW CURRENTLY NEAR DULUTH SLIDING SOUTH...AND SCATTERED
SHOWERS/STORMS DEVELOPING OUT AHEAD OF SURFACE COLD FRONT MOVING
THROUGH. EXPECT HIGHEST CHANCE OF SHOWERS/STORMS AT KRST/KLSE
THROUGH EARLY EVENING...THEN AS DRIER AIR WORKS IN AND LOSS OF
DAYTIME HEATING...PRECIP WILL GRADUALLY SUBSIDE. MVFR CLOUDS WILL
HANG ON AT KLSE THIS AFTERNOON...BEING CLOSER TO UPPER LOW AND
STEADY EAST WINDS. AT KRST...EXPECTING A RISE TO VFR CEILINGS THIS
AFTERNOON.
ATTENTION TURNS TO WHETHER AMPLE LOW-LEVEL MOISTURE IN THE
BOUNDARY LAYER WILL LEAD TO FOG AND/OR STRATUS OVERNIGHT. FORECAST
SOUNDINGS SUGGEST BOUNDARY LAYER WINDS TO REMAIN HIGH ENOUGH FOR
MIXING...EXCEPT FOR RIGHT NEAR SURFACE WHERE INVERSION
DEVELOPS...TRAPPING ANY REMAINING MOISTURE. GIVEN CLOUDS/RAIN
TODAY AND EXPECTED CLEARING TONIGHT...CONTINUED MVFR CONDITIONS AT
BOTH TAF SITES. THERE IS POTENTIAL CONDITIONS COULD LOWER TO
IFR...BUT CONFIDENCE ISN/T HIGH ENOUGH TO INCLUDE AT THIS POINT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
241 AM CDT THU AUG 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...ZT