Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/14/12
AREA FORECAST DISCUSSION
NWS ALBANY NY
635 AM EDT SUN AUG 12 2012
.SYNOPSIS...
A LARGE AREA OF LOW PRESSURE ALOFT SITUATED ACROSS
ONTARIO WILL SLOWLY MOVE AWAY FROM THE REGION TODAY. THIS WILL
CONTINUE TO ALLOW FOR SOME WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE EVENING HOURS. GRADUALLY DRIER AIR WILL
FILTER INTO THE REGION AS WEAK HIGH PRESSURE MOVES OVER THE AREA FOR
SUNDAY NIGHT AND MONDAY. ON TUESDAY INTO WEDNESDAY...ANOTHER SLOW
MOVING DISTURBANCE WILL CROSS THE REGION...RETURNING THE CHANCE FOR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 550 AM EDT...MAIN SURGE OF SUBTROPICAL MOISTURE ALONG THE
EASTERN SEABOARD IS WELL EAST OF THE REGION AND HEADING INTO
EASTERN NEW ENGLAND. THIS PRECIP...DUE TO A COMBINATION OF WEAK
ISENTROPIC LIFT AND THE RIGHT FRONT ENTRANCE REGION OF STRONG 115
JET STREAK...LOOKS TO MAINLY REMAIN EAST OF OUR AREA AS IT QUICKLY
SURGES NORTHEASTWARD. HOWEVER...A FEW ISOLATED LIGHT RAIN SHOWERS
HAVE DEVELOPED ACROSS OUR EASTERN ZONES ON THE BACKSIDE OF THIS
RAIN SHIELD. AS A RESULT...HAVE UPDATED POPS/WX TO ACCOUNT FOR ISOLD
RAIN SHOWERS THROUGH THE REMAINDER OF THE EARLY MORNING HOURS FOR
SOUTHEASTERN PARTS OF THE AREA. HAVE ALSO UPDATED TEMPS/TDS TO
ACCOUNT FOR LATEST OBS/TRENDS.
THE UPPER LOW THAT HAS BEEN IMPACTING OUR WEATHER FOR THE PAST
SEVERAL DAYS WILL CONTINUE TO HAVE AN EFFECT ON OUR
WEATHER...ALTHOUGH IT/S STARTING TO FINALLY LOSE ITS GRIP. THE
STACKED UPPER LOW IS CURRENTLY SITUATED OVER EASTERN ONTARIO...AND
IT WILL SLOWLY BE LIFTING NORTH THROUGH THE DAY. AT THE
MOMENT...PLENTY OF MID AND HIGH LEVEL CLOUDINESS IS STREAMING
NORTHWARD COURTESY OF A 115 KT JET STREAK LOCATED JUST EAST OF THE
UPPER LEVEL STORM. THIS SHOULD ALLOW FOR A MOSTLY CLOUDY
MORNING. SOME BREAKS IN THE CLOUDS SHOULD OCCUR BY THE MID
MORNING. AT THE SAME TIME...A WEAK SHORTWAVE SPINNING AROUND THE
MAIN UPPER LOW WILL CROSS THE REGION FOR THE AFTN/EARLY EVENING
HOURS. THIS SHOULD SET OFF SOME SHOWERS/TSTORMS...ESP FOR AREAS TO
THE NORTH OF CAPITAL REGION.
BOTH THE LOCAL HIRESWRF AND 3KM HRRR SHOWS THESE SHOWERS/STORMS TO
BE OF THE PULSE VARIETY...AND NOT QUITE AS POTENT AS RECENT DAYS.
THIS MAKES SENSE WITH 0-6 BULK SHEAR VALUES DROPPING THROUGH THE
AFTN TO ABOUT 20 KTS. MODEL SOUNDINGS SHOW WEAK MID LEVEL LAPSE
RATES...WITH A CAP DEVELOPING SOMEWHERE BETWEEN 600-700 MB. MODEL
CAPE FORECASTS VARY...WITH THE NAM SHOWING 500-1000 J/KG...AND THE
GFS MUCH LESS WITH ONLY A FEW HUNDRED J/KG. AT THIS POINT...IT
DOESN/T APPEAR THAT WE WILL HAVE TO DEAL WITH ANY SEVERE WEATHER
TODAY...AND ANY SHOWER OR TSTORM WILL BE SHORT LIVED AND LACK
ORGANIZATION. SPC AGREES AND PLACES OUR REGION IN JUST GENERAL
THUNDER. WITH PWAT VALUES OF AROUND 1.25 INCHES...WE DON/T EXPECT
WIDESPREAD HVY RAINFALL...AS THE AXIS OF BEST MOISTURE LOOKS TO BE
FOCUSED MORE ACROSS EASTERN NEW ENGLAND. WHILE WE CAN/T TOTALLY
RULE OUT A BRIEF HVY DOWNPOUR WITH ANY STORM...IT DOESN/T APPEAR
THAT FLASH FLOODING WILL BE A CONCERN AS IT WAS YESTERDAY.
MAX TEMPS WILL RANGE FROM THE UPPER 70S ACROSS THE WESTERN DACKS
TO THE UPPER 80S ACROSS THE MID HUDSON VALLEY. TD VALUES WILL
GRADUALLY BE DROPPING THROUGH THE DAY...BUT IT WILL STILL FEEL
MUGGY WITH TD VALUES IN THE 60S F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SURFACE HIGH PRESSURE WILL PASS OVER THE REGION ALONG WITH WEAK
RIDGING ALOFT FOR TONIGHT INTO TOMORROW NIGHT. THIS SHOULD HELP MOST
AREAS DRY. THE EXCEPTION WILL BE ACROSS THE SRN DACKS...WHERE A
BRIEF SHOWER MAY BE POSSIBLE TONIGHT INTO TOMORROW. MIN TEMPS
TONIGHT WILL RANGE FROM THE MID 50S TO MID 60S...AND MAX TEMPS ON
MONDAY LOOK JUST A TAD COOLER THAN TODAY/S...WITH MID 70S TO MID
80S. MIN TEMPS MON NIGHT WILL BE MID 50S TO MID 60S.
ANOTHER POTENT SHORTWAVE ALOFT WILL BEGIN TO HEAD TOWARDS THE
REGION FOR TUESDAY. WITH INCREASING AMOUNTS OF SHEAR AND TDS WELL
INTO THE 60S F...ORGANIZED THUNDERSTORMS ARE POSSIBLE DURING THE
AFTN HOURS. THE POTENCY OF THE TSTORMS WILL DEPEND ON JUST HOW
MUCH INSTABILITY IS IN PLACE. CURRENT NAM/GFS PROJECTIONS SHOWS
1000-2000 J/KG IS POSSIBLE IF ENOUGH CLEARING OCCURS. SPC HAS
PLACED OUR REGION IN THE SEE TEXT PORTION OF THE DAY 3 OUTLOOK.
MAX TEMPS LOOK TO REACH THE MID 80S FOR VALLEY AREAS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WE BEGIN THIS LONG TERM PORTION OF THE FORECAST WITH A DEPARTING
FRONTAL BOUNDARY AS A RATHER PROGRESSIVE UPPER LOW TRACKS ACROSS
MICHIGAN AND INTO LOWER CANADA INTO WEDNESDAY. IN FACT...SIMILAR
TO THE PREVIOUS UPPER LOW FROM THIS WEEKEND...ITS CYCLONIC FLOW
INFLUENCE WILL REMAIN ACROSS THE REGION THROUGH WEDNESDAY. THIS
WILL KEEP CHC-SCT POPS IN THE FORECAST WITH NEAR TO SLIGHTLY BELOW
SEASONABLE TEMPERATURES.
THEREAFTER...A BRIEF PERIOD OF TRANQUILITY AS A NARROW RIDGE OF HIGH
PRESSURE MOVES ACROSS THE REGION BEFORE THE NEXT SYSTEM APPROACHES
FOR THE END OF THE WEEK. THERE ARE TIMING DIFFERENCES WITH RESPECT
TO HOW PROGRESSIVE THIS SYSTEM WILL BE FOR THE REGION. THE ECMWF
REMAINS ON THE SLOWER SIDE OF THE GUIDANCE ENVELOPE WITH THE GFS ON
THE FASTER SIDE. THE DGEX/GGEM ARE SOMEWHAT IN THE MIDDLE WHICH
PLACES OUR REGION PERHAPS INTO A LONGER PERIOD OF TRANQUILITY UNTIL
FRIDAY AFTERNOON AND HEADING INTO THE WEEKEND. WE WILL TAYLOR THOSE
POPS/WX ACCORDINGLY AND WATCH FUTURE TRENDS. IF TIMING WERE TO
COINCIDING WITH MAY DAYTIME HEATING ALONG WITH INCREASING WIND
DYNAMICS...COULD BE AN INTERESTING PERIOD OF WEATHER AT THE END OF
THIS WEEK.
OVERALL...TEMPERATURES THROUGH THE PERIOD WILL AVERAGE NEAR NORMAL
WITH PRECIPITATION AT TO ABOVE NORMAL WHICH WILL BE HIGHLY DEPENDENT
ON CONVECTIVE ELEMENTS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
WHERE FOG DEVELOPED SHOULD QUICKLY LIFT INTO AN MVFR FLIGHT
CATEGORIES THIS EARLY SUNDAY MORNING. THEN A VARIETY OF CLOUD
LEVELS WILL BE ACROSS THE REGION WITH THE EXPECTATIONS OF THESE
CLOUDS REMAINING AT OR ABOVE VFR FLIGHT THRESHOLDS. LATER THIS
AFTERNOON...WE WILL WATCH A WEAK SURFACE TROUGH AND DEPARTING UPPER
LOW PROVIDE ANOTHER CHANCE FOR SCATTERED CONVECTION FOR THE REGION.
WE WILL CONTINUE WITH THE PREVIOUS FORECAST IDEA WITH PLACING A VCSH
AT ALL TERMINALS FROM THE NOON HOUR AND INTO THE AFTERNOON HOURS.
LATER TONIGHT...WE WILL ONCE AGAIN FACE THE POTENTIAL FOR MVFR TO
IFR CONDITIONS DUE TO LOW CLOUDS AND/OR FOG FOR FAVORED LOCATIONS.
OUTLOOK...
MON-MON NT...VFR. NO SIG WX.
TUE...VFR/MVFR. CHC SHRA/TSRA.
TUE NT-THU...MAINLY VFR. NO SIG WX EXP AT THIS TIME. CHC MVFR/IFR
WITH BR/FG AT NIGHT.
&&
.FIRE WEATHER...
LOW PRESSURE WILL CONTINUE TO MOVE AWAY FROM THE
AREA...HOWEVER...SOME ADDITIONAL RAIN SHOWERS AND THUNDERSTORMS
ARE POSSIBLE TODAY. THIS WILL KEEP ANY FIRE WEATHER CONCERNS TO A
MINIMUM. RH VALUES WILL BE NEAR 100 PERCENT THIS MORNING...BEFORE
DROPPING TO NEAR 40-50 PERCENT FOR THE AFTN HOURS. RH VALUES WILL
RETURN TO NEAR 100 PERCENT AGAIN TONIGHT. LIGHT S-SW WINDS ARE
EXPECTED FOR TODAY AND TONIGHT.
&&
.HYDROLOGY...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
TODAY...ESPECIALLY FOR AREAS NORTH OF THE CAPITAL REGION DURING
THE AFTERNOON AND EVENING HOURS. RAINFALL AMOUNTS WILL VARY
GREATLY...BUT WILL GENERALLY BE MUCH LESS THAN SATURDAY/S AMOUNTS.
WHILE ANY RAIN SHOWER OR THUNDERSTORM MAY CONTAIN A BRIEF BURST
OF HEAVIER RAIN...NO FLOODING IS EXPECTED...ALTHOUGH AREAS OF POOR
DRAINAGE OR URBAN AREAS COULD SEE PONDING OF WATER. WITH THE
ISOLATED TO SCATTERED NATURE OF THE RAINFALL...MAIN STEM RIVERS
SHOULD SEE LITTLE TO NO IMPACT FROM TODAY/S EXPECTED RAINFALL.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS ALBANY NY
551 AM EDT SUN AUG 12 2012
.SYNOPSIS...
A LARGE AREA OF LOW PRESSURE ALOFT SITUATED ACROSS
ONTARIO WILL SLOWLY MOVE AWAY FROM THE REGION TODAY. THIS WILL
CONTINUE TO ALLOW FOR SOME WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE EVENING HOURS. GRADUALLY DRIER AIR WILL
FILTER INTO THE REGION AS WEAK HIGH PRESSURE MOVES OVER THE AREA FOR
SUNDAY NIGHT AND MONDAY. ON TUESDAY INTO WEDNESDAY...ANOTHER SLOW
MOVING DISTURBANCE WILL CROSS THE REGION...RETURNING THE CHANCE FOR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 550 AM EDT...MAIN SURGE OF SUBTROPICAL MOISTURE ALONG THE
EASTERN SEABOARD IS WELL EAST OF THE REGION AND HEADING INTO
EASTERN NEW ENGLAND. THIS PRECIP...DUE TO A COMBINATION OF WEAK
ISENTROPIC LIFT AND THE RIGHT FRONT ENTRANCE REGION OF STRONG 115
JET STREAK...LOOKS TO MAINLY REMAIN EAST OF OUR AREA AS IT QUICKLY
SURGES NORTHEASTWARD. HOWEVER...A FEW ISOLATED LIGHT RAIN SHOWERS
HAVE DEVELOPED ACROSS OUR EASTERN ZONES ON THE BACKSIDE OF THIS
RAIN SHIELD. AS A RESULT...HAVE UPDATED POPS/WX TO ACCOUNT FOR ISOLD
RAIN SHOWERS THROUGH THE REMAINDER OF THE EARLY MORNING HOURS FOR
SOUTHEASTERN PARTS OF THE AREA. HAVE ALSO UPDATED TEMPS/TDS TO
ACCOUNT FOR LATEST OBS/TRENDS.
THE UPPER LOW THAT HAS BEEN IMPACTING OUR WEATHER FOR THE PAST
SEVERAL DAYS WILL CONTINUE TO HAVE AN EFFECT ON OUR
WEATHER...ALTHOUGH IT/S STARTING TO FINALLY LOSE ITS GRIP. THE
STACKED UPPER LOW IS CURRENTLY SITUATED OVER EASTERN ONTARIO...AND
IT WILL SLOWLY BE LIFTING NORTH THROUGH THE DAY. AT THE
MOMENT...PLENTY OF MID AND HIGH LEVEL CLOUDINESS IS STREAMING
NORTHWARD COURTESY OF A 115 KT JET STREAK LOCATED JUST EAST OF THE
UPPER LEVEL STORM. THIS SHOULD ALLOW FOR A MOSTLY CLOUDY
MORNING. SOME BREAKS IN THE CLOUDS SHOULD OCCUR BY THE MID
MORNING. AT THE SAME TIME...A WEAK SHORTWAVE SPINNING AROUND THE
MAIN UPPER LOW WILL CROSS THE REGION FOR THE AFTN/EARLY EVENING
HOURS. THIS SHOULD SET OFF SOME SHOWERS/TSTORMS...ESP FOR AREAS TO
THE NORTH OF CAPITAL REGION.
BOTH THE LOCAL HIRESWRF AND 3KM HRRR SHOWS THESE SHOWERS/STORMS TO
BE OF THE PULSE VARIETY...AND NOT QUITE AS POTENT AS RECENT DAYS.
THIS MAKES SENSE WITH 0-6 BULK SHEAR VALUES DROPPING THROUGH THE
AFTN TO ABOUT 20 KTS. MODEL SOUNDINGS SHOW WEAK MID LEVEL LAPSE
RATES...WITH A CAP DEVELOPING SOMEWHERE BETWEEN 600-700 MB. MODEL
CAPE FORECASTS VARY...WITH THE NAM SHOWING 500-1000 J/KG...AND THE
GFS MUCH LESS WITH ONLY A FEW HUNDRED J/KG. AT THIS POINT...IT
DOESN/T APPEAR THAT WE WILL HAVE TO DEAL WITH ANY SEVERE WEATHER
TODAY...AND ANY SHOWER OR TSTORM WILL BE SHORT LIVED AND LACK
ORGANIZATION. SPC AGREES AND PLACES OUR REGION IN JUST GENERAL
THUNDER. WITH PWAT VALUES OF AROUND 1.25 INCHES...WE DON/T EXPECT
WIDESPREAD HVY RAINFALL...AS THE AXIS OF BEST MOISTURE LOOKS TO BE
FOCUSED MORE ACROSS EASTERN NEW ENGLAND. WHILE WE CAN/T TOTALLY
RULE OUT A BRIEF HVY DOWNPOUR WITH ANY STORM...IT DOESN/T APPEAR
THAT FLASH FLOODING WILL BE A CONCERN AS IT WAS YESTERDAY.
MAX TEMPS WILL RANGE FROM THE UPPER 70S ACROSS THE WESTERN DACKS
TO THE UPPER 80S ACROSS THE MID HUDSON VALLEY. TD VALUES WILL
GRADUALLY BE DROPPING THROUGH THE DAY...BUT IT WILL STILL FEEL
MUGGY WITH TD VALUES IN THE 60S F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SURFACE HIGH PRESSURE WILL PASS OVER THE REGION ALONG WITH WEAK
RIDGING ALOFT FOR TONIGHT INTO TOMORROW NIGHT. THIS SHOULD HELP MOST
AREAS DRY. THE EXCEPTION WILL BE ACROSS THE SRN DACKS...WHERE A
BRIEF SHOWER MAY BE POSSIBLE TONIGHT INTO TOMORROW. MIN TEMPS
TONIGHT WILL RANGE FROM THE MID 50S TO MID 60S...AND MAX TEMPS ON
MONDAY LOOK JUST A TAD COOLER THAN TODAY/S...WITH MID 70S TO MID
80S. MIN TEMPS MON NIGHT WILL BE MID 50S TO MID 60S.
ANOTHER POTENT SHORTWAVE ALOFT WILL BEGIN TO HEAD TOWARDS THE
REGION FOR TUESDAY. WITH INCREASING AMOUNTS OF SHEAR AND TDS WELL
INTO THE 60S F...ORGANIZED THUNDERSTORMS ARE POSSIBLE DURING THE
AFTN HOURS. THE POTENCY OF THE TSTORMS WILL DEPEND ON JUST HOW
MUCH INSTABILITY IS IN PLACE. CURRENT NAM/GFS PROJECTIONS SHOWS
1000-2000 J/KG IS POSSIBLE IF ENOUGH CLEARING OCCURS. SPC HAS
PLACED OUR REGION IN THE SEE TEXT PORTION OF THE DAY 3 OUTLOOK.
MAX TEMPS LOOK TO REACH THE MID 80S FOR VALLEY AREAS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WE BEGIN THIS LONG TERM PORTION OF THE FORECAST WITH A DEPARTING
FRONTAL BOUNDARY AS A RATHER PROGRESSIVE UPPER LOW TRACKS ACROSS
MICHIGAN AND INTO LOWER CANADA INTO WEDNESDAY. IN FACT...SIMILAR
TO THE PREVIOUS UPPER LOW FROM THIS WEEKEND...ITS CYCLONIC FLOW
INFLUENCE WILL REMAIN ACROSS THE REGION THROUGH WEDNESDAY. THIS
WILL KEEP CHC-SCT POPS IN THE FORECAST WITH NEAR TO SLIGHTLY BELOW
SEASONABLE TEMPERATURES.
THEREAFTER...A BRIEF PERIOD OF TRANQUILITY AS A NARROW RIDGE OF HIGH
PRESSURE MOVES ACROSS THE REGION BEFORE THE NEXT SYSTEM APPROACHES
FOR THE END OF THE WEEK. THERE ARE TIMING DIFFERENCES WITH RESPECT
TO HOW PROGRESSIVE THIS SYSTEM WILL BE FOR THE REGION. THE ECMWF
REMAINS ON THE SLOWER SIDE OF THE GUIDANCE ENVELOPE WITH THE GFS ON
THE FASTER SIDE. THE DGEX/GGEM ARE SOMEWHAT IN THE MIDDLE WHICH
PLACES OUR REGION PERHAPS INTO A LONGER PERIOD OF TRANQUILITY UNTIL
FRIDAY AFTERNOON AND HEADING INTO THE WEEKEND. WE WILL TAYLOR THOSE
POPS/WX ACCORDINGLY AND WATCH FUTURE TRENDS. IF TIMING WERE TO
COINCIDING WITH MAY DAYTIME HEATING ALONG WITH INCREASING WIND
DYNAMICS...COULD BE AN INTERESTING PERIOD OF WEATHER AT THE END OF
THIS WEEK.
OVERALL...TEMPERATURES THROUGH THE PERIOD WILL AVERAGE NEAR NORMAL
WITH PRECIPITATION AT TO ABOVE NORMAL WHICH WILL BE HIGHLY DEPENDENT
ON CONVECTIVE ELEMENTS.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
PLENTY OF LOW LEVEL MOISTURE IN PLACE...HOWEVER...AMPLE MID AND HIGH
LEVEL CLOUDS TO COMPLICATE THE TAF FORECAST THE NEXT SEVERAL HOURS.
KGFL-KPSF HAVE ALREADY BEEN IN THE IFR TERRITORY AND BELIEVE THEY
WILL ONCE AGAIN WITH DEWPOINT DEPRESSIONS NEAR ZERO SO HAVE PLACED A
TEMPO GROUP AT THIS TIME. ELSEWHERE...DEWPOINT DEPRESSIONS WERE
WITHIN A FEW DEGREES AND MVFR VISIBILITIES WILL BE POSSIBLE. SO
HAVE PLACE A TEMPO GROUP FOR KPOU-KALB AS WE WILL MONITOR TRENDS
CLOSELY.
SHORTLY AFTER SUNRISE...WHILE LOW LEVEL IMPROVEMENTS SHOULD
COMMENCE...WE WILL WATCH A WEAK SURFACE TROUGH AND DEPARTING UPPER
LOW PROVIDE ANOTHER CHANCE FOR SCATTERED CONVECTION FOR THE REGION.
WE WILL CONTINUE WITH THE PREVIOUS FORECAST IDEA WITH PLACING A VCSH
AT ALL TERMINALS FROM THE NOON HOUR AND INTO THE AFTERNOON.
OUTLOOK...
SUN OVRNT...MAINLY VFR. POSSIBLE MVFR/IFR WITH FG AND/OR LOW
STRATUS.
MON-MON NT...VFR. NO SIG WX.
TUE-WED...VFR/MVFR. CHC SHRA/TSRA.
THU...VFR. NO SIG WX EXP AT THIS TIME.
&&
.FIRE WEATHER...
LOW PRESSURE WILL CONTINUE TO MOVE AWAY FROM THE
AREA...HOWEVER...SOME ADDITIONAL RAIN SHOWERS AND THUNDERSTORMS
ARE POSSIBLE TODAY. THIS WILL KEEP ANY FIRE WEATHER CONCERNS TO A
MINIMUM. RH VALUES WILL BE NEAR 100 PERCENT THIS MORNING...BEFORE
DROPPING TO NEAR 40-50 PERCENT FOR THE AFTN HOURS. RH VALUES WILL
RETURN TO NEAR 100 PERCENT AGAIN TONIGHT. LIGHT S-SW WINDS ARE
EXPECTED FOR TODAY AND TONIGHT.
&&
.HYDROLOGY...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
TODAY...ESPECIALLY FOR AREAS NORTH OF THE CAPITAL REGION DURING
THE AFTERNOON AND EVENING HOURS. RAINFALL AMOUNTS WILL VARY
GREATLY...BUT WILL GENERALLY BE MUCH LESS THAN SATURDAY/S AMOUNTS.
WHILE ANY RAIN SHOWER OR THUNDERSTORM MAY CONTAIN A BRIEF BURST
OF HEAVIER RAIN...NO FLOODING IS EXPECTED...ALTHOUGH AREAS OF POOR
DRAINAGE OR URBAN AREAS COULD SEE PONDING OF WATER. WITH THE
ISOLATED TO SCATTERED NATURE OF THE RAINFALL...MAIN STEM RIVERS
SHOULD SEE LITTLE TO NO IMPACT FROM TODAY/S EXPECTED RAINFALL.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
401 AM EDT SUN AUG 12 2012
.SYNOPSIS...
A LARGE AREA OF LOW PRESSURE ALOFT SITUATED ACROSS
ONTARIO WILL SLOWLY MOVE AWAY FROM THE REGION TODAY. THIS WILL
CONTINUE TO ALLOW FOR SOME WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE EVENING HOURS. GRADUALLY DRIER AIR WILL
FILTER INTO THE REGION AS WEAK HIGH PRESSURE MOVES OVER THE AREA FOR
SUNDAY NIGHT AND MONDAY. ON TUESDAY INTO WEDNESDAY...ANOTHER SLOW
MOVING DISTURBANCE WILL CROSS THE REGION...RETURNING THE CHANCE FOR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 401 AM EDT...THE UPPER LOW THAT HAS BEEN IMPACTING OUR WEATHER
FOR THE PAST SEVERAL DAYS WILL CONTINUE TO HAVE AN EFFECT ON OUR
WEATHER...ALTHOUGH IT/S STARTING TO FINALLY LOSE ITS GRIP. THE
STACKED UPPER LOW IS CURRENTLY SITUATED OVER EASTERN ONTARIO...AND
IT WILL SLOWLY BE LIFTING NORTH THROUGH THE DAY. AT THE
MOMENT...PLENTY OF MID AND HIGH LEVEL CLOUDINESS IS STREAMING
NORTHWARD COURTESY OF A 115 KT JET STREAK LOCATED JUST EAST OF THE
UPPER LEVEL STORM. THIS SHOULD ALLOW FOR A MOSTLY CLOUDY
MORNING...WITH MOST AREAS STAYING DRY. SOME BREAKS IN THE CLOUDS
SHOULD OCCUR BY THE MID MORNING. AT THE SAME TIME...A WEAK
SHORTWAVE SPINNING AROUND THE MAIN UPPER LOW WILL CROSS THE REGION
FOR THE AFTN/EARLY EVENING HOURS. THIS SHOULD SET OFF SOME
SHOWERS/TSTORMS...ESP FOR AREAS TO THE NORTH OF CAPITAL REGION.
BOTH THE LOCAL HIRESWRF AND 3KM HRRR SHOWS THESE SHOWERS/STORMS TO
BE OF THE PULSE VARIETY...AND NOT QUITE AS POTENT AS RECENT DAYS.
THIS MAKES SENSE WITH 0-6 BULK SHEAR VALUES DROPPING THROUGH THE
AFTN TO ABOUT 20 KTS. MODEL SOUNDINGS SHOULD WEAK MID LEVEL LAPSE
RATES...WITH A CAP DEVELOPING SOMEWHERE BETWEEN 600-700 MB. MODEL
CAPE FORECASTS VARY...WITH THE NAM SHOWING 500-1000 J/KG...AND THE
GFS MUCH LESS WITH ONLY A FEW HUNDRED J/KG. AT THIS POINT...IT
DOESN/T APPEAR THAT WILL HAVE TO DEAL WITH ANY SEVERE WEATHER
TODAY...AND ANY SHOWER OR TSTORM WILL BE SHORT LIVED AND LACK
ORGANIZATION. SPC AGREES AND PLACES OUR REGION IN JUST GENERAL
THUNDER. WITH PWAT VALUES OF AROUND 1.25 INCHES...WE DON/T EXPECT
WIDESPREAD HVY RAINFALL...AS THE AXIS OF BEST MOISTURE LOOKS TO BE
FOCUSED MORE ACROSS EASTERN NEW ENGLAND. WHILE WE CAN/T TOTALLY
RULE OUT A BRIEF HVY DOWNPOUR WITH ANY STORM...IT DOESN/T APPEAR
THAT FLASH FLOODING WILL BE A CONCERN AS IT WAS YESTERDAY.
MAX TEMPS WILL RANGE FROM THE UPPER 70S ACROSS THE WESTERN DACKS
TO THE UPPER 80S ACROSS THE MID HUDSON VALLEY. TD VALUES WILL
GRADUALLY BE DROPPING THROUGH THE DAY...BUT IT WILL STILL FEEL
MUGGY WITH TD VALUES IN THE 60S F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SURFACE HIGH PRESSURE WILL PASS OVER THE REGION ALONG WITH WEAK
RIDGING ALOFT FOR TONIGHT INTO TOMORROW NIGHT. THIS SHOULD HELP MOST
AREAS DRY. THE EXCEPTION WILL BE ACROSS THE SRN DACKS...WHERE A
BRIEF SHOWER MAY BE POSSIBLE TONIGHT INTO TOMORROW. MIN TEMPS
TONIGHT WILL RANGE FROM THE MID 50S TO MID 60S...AND MAX TEMPS ON
MONDAY LOOK JUST A TAD COOLER THAN TODAY/S...WITH MID 70S TO MID
80S. MIN TEMPS MON NIGHT WILL BE MID 50S TO MID 60S.
ANOTHER POTENT SHORTWAVE ALOFT WILL BEGIN TO HEAD TOWARDS THE
REGION FOR TUESDAY. WITH INCREASING AMOUNTS OF SHEAR AND TDS WELL
INTO THE 60S F...ORGANIZED THUNDERSTORMS ARE POSSIBLE DURING THE
AFTN HOURS. THE POTENCY OF THE TSTORMS WILL DEPEND ON JUST HOW
MUCH INSTABILITY IS IN PLACE. CURRENT NAM/GFS PROJECTIONS SHOWS
1000-2000 J/KG IS POSSIBLE IF ENOUGH CLEARING OCCURS. SPC HAS
PLACED OUR REGION IN THE SEE TEXT PORTION OF THE DAY 3 OUTLOOK.
MAX TEMPS LOOK TO REACH THE MID 80S FOR VALLEY AREAS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WE BEGIN THIS LONG TERM PORTION OF THE FORECAST WITH A DEPARTING
FRONTAL BOUNDARY AS A RATHER PROGRESSIVE UPPER LOW TRACKS ACROSS
MICHIGAN AND INTO LOWER CANADA INTO WEDNESDAY. IN FACT...SIMILAR
TO THE PREVIOUS UPPER LOW FROM THIS WEEKEND...ITS CYCLONIC FLOW
INFLUENCE WILL REMAIN ACROSS THE REGION THROUGH WEDNESDAY. THIS
WILL KEEP CHC-SCT POPS IN THE FORECAST WITH NEAR TO SLIGHTLY BELOW
SEASONABLE TEMPERATURES.
THEREAFTER...A BRIEF PERIOD OF TRANQUILITY AS A NARROW RIDGE OF HIGH
PRESSURE MOVES ACROSS THE REGION BEFORE THE NEXT SYSTEM APPROACHES
FOR THE END OF THE WEEK. THERE ARE TIMING DIFFERENCES WITH RESPECT
TO HOW PROGRESSIVE THIS SYSTEM WILL BE FOR THE REGION. THE ECMWF
REMAINS ON THE SLOWER SIDE OF THE GUIDANCE ENVELOPE WITH THE GFS ON
THE FASTER SIDE. THE DGEX/GGEM ARE SOMEWHAT IN THE MIDDLE WHICH
PLACES OUR REGION PERHAPS INTO A LONGER PERIOD OF TRANQUILITY UNTIL
FRIDAY AFTERNOON AND HEADING INTO THE WEEKEND. WE WILL TAYLOR THOSE
POPS/WX ACCORDINGLY AND WATCH FUTURE TRENDS. IF TIMING WERE TO
COINCIDING WITH MAY DAYTIME HEATING ALONG WITH INCREASING WIND
DYNAMICS...COULD BE AN INTERESTING PERIOD OF WEATHER AT THE END OF
THIS WEEK.
OVERALL...TEMPERATURES THROUGH THE PERIOD WILL AVERAGE NEAR NORMAL
WITH PRECIPITATION AT TO ABOVE NORMAL WHICH WILL BE HIGHLY DEPENDENT
ON CONVECTIVE ELEMENTS.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
PLENTY OF LOW LEVEL MOISTURE IN PLACE...HOWEVER...AMPLE MID AND HIGH
LEVEL CLOUDS TO COMPLICATE THE TAF FORECAST THE NEXT SEVERAL HOURS.
KGFL-KPSF HAVE ALREADY BEEN IN THE IFR TERRITORY AND BELIEVE THEY
WILL ONCE AGAIN WITH DEWPOINT DEPRESSIONS NEAR ZERO SO HAVE PLACED A
TEMPO GROUP AT THIS TIME. ELSEWHERE...DEWPOINT DEPRESSIONS WERE
WITHIN A FEW DEGREES AND MVFR VISIBILITIES WILL BE POSSIBLE. SO
HAVE PLACE A TEMPO GROUP FOR KPOU-KALB AS WE WILL MONITOR TRENDS
CLOSELY.
SHORTLY AFTER SUNRISE...WHILE LOW LEVEL IMPROVEMENTS SHOULD
COMMENCE...WE WILL WATCH A WEAK SURFACE TROUGH AND DEPARTING UPPER
LOW PROVIDE ANOTHER CHANCE FOR SCATTERED CONVECTION FOR THE REGION.
WE WILL CONTINUE WITH THE PREVIOUS FORECAST IDEA WITH PLACING A VCSH
AT ALL TERMINALS FROM THE NOON HOUR AND INTO THE AFTERNOON.
OUTLOOK...
SUN OVRNT...MAINLY VFR. POSSIBLE MVFR/IFR WITH FG AND/OR LOW
STRATUS.
MON-MON NT...VFR. NO SIG WX.
TUE-WED...VFR/MVFR. CHC SHRA/TSRA.
THU...VFR. NO SIG WX EXP AT THIS TIME.
&&
.FIRE WEATHER...
LOW PRESSURE WILL CONTINUE TO MOVE AWAY FROM THE
AREA...HOWEVER...SOME ADDITIONAL RAIN SHOWERS AND THUNDERSTORMS
ARE POSSIBLE TODAY. THIS WILL KEEP ANY FIRE WEATHER CONCERNS TO A
MINIMUM. RH VALUES WILL BE NEAR 100 PERCENT THIS MORNING...BEFORE
DROPPING TO NEAR 40-50 PERCENT FOR THE AFTN HOURS. RH VALUES WILL
RETURN TO NEAR 100 PERCENT AGAIN TONIGHT. LIGHT S-SW WINDS ARE
EXPECTED FOR TODAY AND TONIGHT.
&&
.HYDROLOGY...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
TODAY...ESPECIALLY FOR AREAS NORTH OF THE CAPITAL REGION DURING
THE AFTERNOON AND EVENING HOURS. RAINFALL AMOUNTS WILL VARY
GREATLY...BUT WILL GENERALLY BE MUCH LESS THAN SATURDAY/S AMOUNTS.
WHILE ANY RAIN SHOWER OR THUNDERSTORM MAY CONTAIN A BRIEF BURST
OF HEAVIER RAIN...NO FLOODING IS EXPECTED...ALTHOUGH AREAS OF POOR
DRAINAGE OR URBAN AREAS COULD SEE PONDING OF WATER. WITH THE
ISOLATED TO SCATTERED NATURE OF THE RAINFALL...MAIN STEM RIVERS
SHOULD SEE LITTLE TO NO IMPACT FROM TODAY/S EXPECTED RAINFALL.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
940 PM EDT MON AUG 13 2012
.UPDATE...HAVE TWEAKED POPS AGAIN...KEEPING CHANCE OR SLIGHT CHANCE
OVER MUCH OF THE CWA EXCEPT EAST CENTRAL. WATCHING THUNDERSTORMS IN
MISSISSIPPI AND MAY HAVE TO ADJUST POPS AGAIN LATER. WITH RAIN
COOLED AIR ACROSS THE NORTHWEST...HOURLY TEMPERATURES HAVE FALLEN
MORE RAPIDLY AND HAVE TRIED TO ADJUST FOR THAT IN THE GRIDS.
41
.PREVIOUS UPDATE...
DIFFICULT FORECAST FOR TONIGHT...WITH NONE OF THE MODELS REALLY
HAVING A GOOD HANDLE ON THE CURRENT SHOWER AND THUNDERSTORM ACTIVITY.
HAVE SIGNIFICANTLY UPDATED POPS AND WEATHER GRIDS TO ACCOUNT FOR
CURRENT CONVECTION ASSOCIATED WITH MCS THAT MOVED EASTWARD OUT OF
TN/AL THIS AFTERNOON. LATEST LAPS SHOWING BEST INSTABILITY ALONG THE
GA/AL LINE...WITH AREAS FURTHER EAST FAR MORE STABLE. IN
GENERAL...EXPECT AN OVERALL WEAKENING TREND AS THIS LARGE AREA OF
PRECIPITATION CONTINUES TO MOVE EASTWARD.
WILL BE MAKING PERIODIC UPDATES TO THE FORECAST AS NECESSARY AS
THIS EVENT CONTINUES TO UNFOLD. HAVE GONE AHEAD AND CANCELLED THE
SVR WATCH FOR THE FAR NORTHEAST PORTION OF THE STATE.
31
&&
.PREV DISCUSSION... /ISSUED 308 PM EDT MON AUG 13 2012/
..SEVERE STORMS EXPECTED THROUGH THIS EVENING EXTREME NW GEORGIA...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ALL EYES ON MCS OVER TENNESSEE AND ALABAMA WHICH CONTINUES TO MAKE
STEADY PROGRESS TO THE EAST. NOW HAVE A WATCH UP FOR THE EXTREME
NW CORNER OF THE FORECAST AREA WHERE THERE IS IRONICALLY LITTLE TO
NO INSTABILITY AT THIS TIME. SYSTEM HAS HOWEVER BEEN ABLE TO BRING
ALONG ITS OWN ENHANCED MOISTURE AND INSTABILITY ALTHOUGH ITS
ABILITY TO DO SO AS IT APPROACHES THE FORECAST AREA REMAINS IN
QUESTION. RAP SHORT TERM GUIDANCE DOES SHOW INCREASED INSTABILITY
WITHIN THE NEXT 2 HOURS PUSHING INTO THE NW ZONES BUT ONLY ON THE
ORDER OF 1500 TO 2000 J/KG...MUCH LESS THAN UPSTREAM VALUES WE HAVE
SEEN. SO IN SHORT...EXPECTING SVR POTENTIAL TO INCREASE FOR THE
EXTREME NW AND WESTERN TIER OVER THE NEXT SEVERAL HOURS BUT TRENDS
IN INSTABILITY SUGGEST A LIMITED TIMEFRAME FOR CONVECTIVE
POTENTIAL. ALSO WATCHING DEVELOPING AREA OF DCAPE IN EXCESS OF
1000 J/KG WHICH COULD ALLOW FOR ISOLATED SVR OUTSIDE OF CURRENT
WATCH AREA FROM COLUMBUS UP TO LA GRANGE.
QUESTIONS ALSO SURROUND HOW FAR ACTUAL LINE OF SHOWERS AND STORMS
MAKES IT TO THE EAST. AS MENTIONED...EXPECTING A SHARP INSTABILITY
GRADIENT AND MOMENTUM LOOKS TO ONLY TAKE THIS SYSTEM SO FAR. HRRR
IS DIMINISHING LINE AND THEN GENERATES NEW CONVECTION ALONG ACTUAL
FRONT INTO THE OVERNIGHT HOURS. GIVEN CURRENT TRENDS...WILL EXPAND
POP COVERAGE SLIGHTLY EASTWARD BUT ONLY CARRY LOW END CHANCE POPS
INTO THE OVERNIGHT PERIOD FOR THE ATLANTA METRO AND POINTS NORTH
AND WEST.
BY 12Z...FRONT WILL SAG INTO NORTH GEORGIA WITH DRIER AIR
BEGINNING TO FILTER IN. WILL BE IN LARGE SCALE TROUGH PATTERN BUT
NO NOTABLE SHORTWAVES EMBEDDED IN FLOW UNTIL 00Z. THIS COULD
ENHANCE POPS FIELD BUT PRIMARILY OVER THE SOUTHERN TIER WHERE I
HAVE INCLUDED LIKELY POPS.
DEESE
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO SIGNIFICANT CHANGES PLANNED.
BDL
MEDIUM RANGE MODELS REMAIN CONSISTENT THROUGH THE EXTENDED
FORECAST PERIOD KEEPING THE EASTERN U.S. UNDER PERSISTENT LONG
WAVE TROUGHING. ALTHOUGH THE LARGE SCALE PATTERN REMAINS FAIRLY
STATIC...THE SMALLER SCALE REMAINS QUITE ACTIVE AS SHORT WAVES
SWING THROUGH THE TROUGH DIGGING OUT OF THE NORTHERN PLAINS INTO
THE OHIO VALLEY. THIS PATTERN KEEPS THE BEST UPPER DYNAMICS NORTH
OF THE REGION...BUT MANAGES TO DRIVE A SERIES OF ASSOCIATED
SURFACE FRONTS THROUGH THE STATE. FIRST SYSTEM IS EXITING AS WE
HEAD INTO THE EXTENDED PERIOD SO ANOTHER SHOT OF MILDER AND FAIRLY
DRY AIR SETTLES IN FOR THE MIDDLE OF THE WEEK. NEXT SYSTEM IS
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND. THIS
CORRESPONDS WELL WITH PREVIOUS MODEL RUNS SO THERE ARE NO
SIGNIFICANT CHANGES TO THE PREVIOUS EXTENDED FORECAST THEMES.
20
AVIATION...
00Z UPDATE...
REMNANTS OF SQUALL LINE PASSING ACROSS NORTH GA THIS EVENING. MORE
CONVECTION POSSIBLE OVERNIGHT BUT SHOULD BE SCATTERED. WILL HAVE TO
AMEND AS NEEDED TERMINALS THAT WILL BE AFFECTED. SHOULD BE VFR FOR
MUCH OF THE NIGHT...HOWEVER DUE TO PREVIOUS RAIN SOME LOCAL IFR
CEILINGS AND VISIBILITIES ARE POSSIBLE. TIMING ON THIS IS UNCERTAIN.
SCATTERED CONVECTION SHOULD DEVELOP AGAIN TUESDAY AFTERNOON. WINDS
GENERALLY LIGHT AND VARIABLE OVERNIGHT...SOUTHWEST 5 TO 10KT AFTER
14Z TUESDAY.
//ATL CONFIDENCE...00Z UPDATE...
LOW TO MEDIUM ON IFR CEILINGS AND VISIBILITY OVERNIGHT.
MEDIUM TO HIGH ON REMAINING ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 90 69 91 / 20 40 20 10
ATLANTA 70 87 71 88 / 60 30 20 10
BLAIRSVILLE 63 83 64 85 / 50 30 20 5
CARTERSVILLE 67 87 68 89 / 70 30 20 5
COLUMBUS 71 90 74 91 / 60 40 20 20
GAINESVILLE 67 87 69 88 / 50 30 20 10
MACON 67 91 72 91 / 20 50 30 20
ROME 67 87 68 89 / 50 30 20 5
PEACHTREE CITY 67 87 69 89 / 60 30 20 10
VIDALIA 70 92 75 92 / 10 60 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....31
AVIATION...41
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
800 PM EDT MON AUG 13 2012
.UPDATE...
DIFFICULT FORECAST FOR TONIGHT...WITH NONE OF THE MODELS REALLY
HAVING A GOOD HANDLE ON THE CURRENT SHOWER AND THUNDERSTORM ACTIVITY.
HAVE SIGNIFICANTLY UPDATED POPS AND WEATHER GRIDS TO ACCOUNT FOR
CURRENT CONVECTION ASSOCIATED WITH MCS THAT MOVED EASTWARD OUT OF
TN/AL THIS AFTERNOON. LATEST LAPS SHOWING BEST INSTABILITY ALONG THE
GA/AL LINE...WITH AREAS FURTHER EAST FAR MORE STABLE. IN
GENERAL...EXPECT AN OVERALL WEAKENING TREND AS THIS LARGE AREA OF
PRECIPITATION CONTINUES TO MOVE EASTWARD.
WILL BE MAKING PERIODIC UPDATES TO THE FORECAST AS NECESSARY AS
THIS EVENT CONTINUES TO UNFOLD. HAVE GONE AHEAD AND CANCELLED THE
SVR WATCH FOR THE FAR NORTHEAST PORTION OF THE STATE.
31
&&
.PREV DISCUSSION... /ISSUED 308 PM EDT MON AUG 13 2012/
..SEVERE STORMS EXPECTED THROUGH THIS EVENING EXTREME NW GEORGIA...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ALL EYES ON MCS OVER TENNESSEE AND ALABAMA WHICH CONTINUES TO MAKE
STEADY PROGRESS TO THE EAST. NOW HAVE A WATCH UP FOR THE EXTREME
NW CORNER OF THE FORECAST AREA WHERE THERE IS IRONICALLY LITTLE TO
NO INSTABILITY AT THIS TIME. SYSTEM HAS HOWEVER BEEN ABLE TO BRING
ALONG ITS OWN ENHANCED MOISTURE AND INSTABILITY ALTHOUGH ITS
ABILITY TO DO SO AS IT APPROACHES THE FORECAST AREA REMAINS IN
QUESTION. RAP SHORT TERM GUIDANCE DOES SHOW INCREASED INSTABILITY
WITHIN THE NEXT 2 HOURS PUSHING INTO THE NW ZONES BUT ONLY ON THE
ORDER OF 1500 TO 2000 J/KG...MUCH LESS THAN UPSTREAM VALUES WE HAVE
SEEN. SO IN SHORT...EXPECTING SVR POTENTIAL TO INCREASE FOR THE
EXTREME NW AND WESTERN TIER OVER THE NEXT SEVERAL HOURS BUT TRENDS
IN INSTABILITY SUGGEST A LIMITED TIMEFRAME FOR CONVECTIVE
POTENTIAL. ALSO WATCHING DEVELOPING AREA OF DCAPE IN EXCESS OF
1000 J/KG WHICH COULD ALLOW FOR ISOLATED SVR OUTSIDE OF CURRENT
WATCH AREA FROM COLUMBUS UP TO LA GRANGE.
QUESTIONS ALSO SURROUND HOW FAR ACTUAL LINE OF SHOWERS AND STORMS
MAKES IT TO THE EAST. AS MENTIONED...EXPECTING A SHARP INSTABILITY
GRADIENT AND MOMENTUM LOOKS TO ONLY TAKE THIS SYSTEM SO FAR. HRRR
IS DIMINISHING LINE AND THEN GENERATES NEW CONVECTION ALONG ACTUAL
FRONT INTO THE OVERNIGHT HOURS. GIVEN CURRENT TRENDS...WILL EXPAND
POP COVERAGE SLIGHTLY EASTWARD BUT ONLY CARRY LOW END CHANCE POPS
INTO THE OVERNIGHT PERIOD FOR THE ATLANTA METRO AND POINTS NORTH
AND WEST.
BY 12Z...FRONT WILL SAG INTO NORTH GEORGIA WITH DRIER AIR
BEGINNING TO FILTER IN. WILL BE IN LARGE SCALE TROUGH PATTERN BUT
NO NOTABLE SHORTWAVES EMBEDDED IN FLOW UNTIL 00Z. THIS COULD
ENHANCE POPS FIELD BUT PRIMARILY OVER THE SOUTHERN TIER WHERE I
HAVE INCLUDED LIKELY POPS.
DEESE
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO SIGNIFICANT CHANGES PLANNED.
BDL
MEDIUM RANGE MODELS REMAIN CONSISTENT THROUGH THE EXTENDED
FORECAST PERIOD KEEPING THE EASTERN U.S. UNDER PERSISTENT LONG
WAVE TROUGHING. ALTHOUGH THE LARGE SCALE PATTERN REMAINS FAIRLY
STATIC...THE SMALLER SCALE REMAINS QUITE ACTIVE AS SHORT WAVES
SWING THROUGH THE TROUGH DIGGING OUT OF THE NORTHERN PLAINS INTO
THE OHIO VALLEY. THIS PATTERN KEEPS THE BEST UPPER DYNAMICS NORTH
OF THE REGION...BUT MANAGES TO DRIVE A SERIES OF ASSOCIATED
SURFACE FRONTS THROUGH THE STATE. FIRST SYSTEM IS EXITING AS WE
HEAD INTO THE EXTENDED PERIOD SO ANOTHER SHOT OF MILDER AND FAIRLY
DRY AIR SETTLES IN FOR THE MIDDLE OF THE WEEK. NEXT SYSTEM IS
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND. THIS
CORRESPONDS WELL WITH PREVIOUS MODEL RUNS SO THERE ARE NO
SIGNIFICANT CHANGES TO THE PREVIOUS EXTENDED FORECAST THEMES.
20
AVIATION...
00Z UPDATE...
REMNANTS OF SQUALL LINE PASSING ACROSS NORTH GA THIS EVENING. MORE
CONVECTION POSSIBLE OVERNIGHT BUT SHOULD BE SCATTERED. WILL HAVE TO
AMEND AS NEEDED TERMINALS THAT WILL BE AFFECTED. SHOULD BE VFR FOR
MUCH OF THE NIGHT...HOWEVER DUE TO PREVIOUS RAIN SOME LOCAL IFR
CEILINGS AND VISIBILITIES ARE POSSIBLE. TIMING ON THIS IS UNCERTAIN.
SCATTERED CONVECTION SHOULD DEVELOP AGAIN TUESDAY AFTERNOON. WINDS
GENERALLY LIGHT AND VARIABLE OVERNIGHT...SOUTHWEST 5 TO 10KT AFTER
14Z TUESDAY.
//ATL CONFIDENCE...00Z UPDATE...
LOW TO MEDIUM ON IFR CEILINGS AND VISIBILITY OVERNIGHT.
MEDIUM TO HIGH ON REMAINING ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 90 69 91 / 20 40 20 10
ATLANTA 70 87 71 88 / 60 30 20 10
BLAIRSVILLE 63 83 64 85 / 50 30 20 5
CARTERSVILLE 67 87 68 89 / 70 30 20 5
COLUMBUS 71 90 74 91 / 60 40 20 20
GAINESVILLE 67 87 69 88 / 50 30 20 10
MACON 67 91 72 91 / 20 50 30 20
ROME 67 87 68 89 / 50 30 20 5
PEACHTREE CITY 67 87 69 89 / 60 30 20 10
VIDALIA 70 92 75 92 / 10 60 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....31
AVIATION...41
AREA FORECAST DISCUSSION
NWS LINCOLN IL
850 PM CDT MON AUG 13 2012
.DISCUSSION...
ISSUED 850 PM CDT MON AUG 13 2012
CLEARING LINE HAS PUSHED TO ABOUT A MACOMB-PEORIA-LACON LINE AT
MID EVENING. MAIN QUESTION IS HOW MUCH FURTHER SOUTH THIS WILL
MAKE IT. HAVE BEEN SEEING SOME EVIDENCE THAT AREAS EAST OF I-39
ARE NOT CLEARING OUT QUITE AS FAST AS FURTHER SOUTHWEST...AND
AN AREA OF STRATUS BELOW 1000 FEET HAS BEEN DEVELOPING FROM
DECATUR TO PONTIAC. AWIPS TIME-OF-ARRIVAL TOOL AND RAP MODEL CLOUD
GUIDANCE HAS THE WESTERN CWA MOSTLY CLEAR BEFORE MIDNIGHT...BUT
THE RAP INDICATES THE CLOUDS ACROSS THE EAST WILL BE TOUGH TO
ERODE WITH A BOUNDARY STILL IN THE AREA. HAVE ADDED SOME MENTION
OF PATCHY FOG OVERNIGHT...ESPECIALLY IN AREAS THAT WILL SEE SOME
SUBSTANTIAL CLEARING AND LIGHTER WINDS.
UPDATED ZONES/GRIDS HAVE BEEN SENT.
GEELHART
&&
.AVIATION...
ISSUED 618 PM CDT MON AUG 13 2012
MAIN CONCERN IS WITH POTENTIAL FOR MVFR/IFR CEILINGS AND
VISIBILITIES THROUGH EARLY TUESDAY MORNING. LARGE STRATOCUMULUS
SHIELD COVERING THE TAF SITES EARLY THIS EVENING...WITH CEILINGS
GENERALLY IN THE MVFR RANGE...BUT VISIBLE SATELLITE IMAGERY
SHOWING THE CLEARING LINE MAKING GOOD SOUTHWARD PROGRESS. SHOULD
SEE KPIA SCATTER OUT AROUND 02Z RANGING TO AROUND 06Z AT KDEC.
HOWEVER...RAP MODEL SHOWING A LARGE AREA OF LOW STRATUS BELOW 1000
FEET DEVELOPING OVER EAST CENTRAL ILLINOIS AND WESTERN INDIANA
LATE THIS EVENING. HAVE A FEELING THAT KCMI WILL BE STUCK IN THE
CLOUDS THROUGH THE NIGHT...AND KDEC MAY BE ON THE BORDER. WILL
LIKELY SEE SOME LIGHT FOG OF 4-6SM VISIBILITIES AT ALL SITES...
BUT WILL NEED TO WATCH FOR SOME LOWER VALUES AT TIMES...ESPECIALLY
AS SKIES CLEAR AND WINDS BECOME LIGHTER. BY MID TO LATE TUESDAY
MORNING...VFR CONDITIONS WILL PREVAIL.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT MON AUG 13 2012
CLOUDY...COOL...AND SHOWERY WEATHER WILL CONTINUE THIS EVENING
BEFORE THE SURFACE LOW FINALLY DEPARTS INTO INDIANA. FOR TUESDAY
AND WEDNESDAY...SURFACE HIGH PRESSURE WILL KEEP THE WEATHER
QUIET...WITH MUCH WARMER TEMPS ON WEDNESDAY. THEN A COLD FRONT
WILL BRING SHOWERS AND STORMS BACK TO THE AREA THURSDAY AND
THURSDAY NIGHT...FOLLOWED BY A RETURN TO BELOW NORMAL TEMPS FOR
NEXT WEEKEND AND INTO NEXT WEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY.
INSTABILITY NEAR THE SURFACE LOW WILL ALLOW SHOWERS AND POSSIBLY A
FEW THUNDERSTORMS TO LINGER INTO THE EVENING...MAINLY EAST OF
I-55. THE LOW CENTER IS EXPECTED TO TRACK JUST SOUTH OF
SPRINGFIELD TO LAWRENCEVILLE. THE SPC DY1 OUTLOOK STILL INCLUDES
OUR FAR SOUTHEAST COUNTIES NEAR LWV...WHERE MU CAPES ARE NEAR 1000
J/KG AND EFFECTIVE SHEAR IS 25-30KT. BY MIDNIGHT...THE LOW SHOULD
BE INTO INDIANA...AND INTO KY BY 12Z TUES. WE KEPT SOME SLIGHT
CHANCE POPS AFTER MIDNIGHT EAST OF I-57.
TUESDAY WILL SEE HIGH PRESSURE ARRIVING...BUT THE TYPICALLY COOLER
AIR BEHIND THE LOW WILL BE SHORT LIVED AS 850MB TEMPS WARM FROM 12
TO 16C TUES AFTERNOON. THAT WARMING ALONG WITH INCREASING SUNSHINE
AS THE DAY PROGRESSES WILL HELP TEMPS WARM INTO THE LOW TO MID
80S. THAT WARMING TREND WILL INTENSIFY ON WEDNESDAY AS THE THERMAL
RIDGE PEAKS AHEAD OF THE APPROACHING COLD FRONT. HIGHS ON WED ARE
EXPECTED TO CLIMB ABOVE NORMAL IN THE UPPER 80S TO LOWER 90S.
A FEW SHOWERS MAY DEVELOP THURSDAY MORNING...BUT THE BULK OF THE
PRECIPITATION ACCUMULATION SHOULD COME THURS AFTERNOON AND
EVENING. THE NAM IS THE FAST OUTLIER WITH TIMING OF THE FRONT INTO
THE MID CWA BY 18Z...BUT WE DECIDED TO CONTINUE WITH THE CONSENSUS
SLOWER SOLUTION OF THE GFS/CANADIAN GEM/ECMWF. WE HAVE LIKELY POPS
IN THE NW HALF THURS AND THE SE HALF THURS NIGHT.
LONG TERM...FRIDAY THROUGH MONDAY.
A COOLER AIRMASS WILL SETTLE INTO THE UPPER MIDWEST FOR FRIDAY AND
LINGER THROUGH MONDAY...WITH BELOW NORMAL TEMPS ACROSS THE BOARD.
AS THE UPPER TROUGH AXIS MOVES ACROSS CENTRAL IL ON FRIDAY...WE
CANT RULE OUT A FEW SPRINKLES DEVELOPING IN THE STEEPER LAPSE
RATES. HOWEVER...WE KEPT THE FORECAST DRY FOR NOW. THE REMAINDER
OF THE WEEKEND AND INTO MONDAY IS FORECAST TO BE DRY BY THE ECMWF.
THE OVERLY MOIST GFS IS GENERATING DIURNAL SHOWERS EACH DAY OF THE
EXTENDED. NORTHWEST FLOW ALOFT MAY ALLOW FOR A STRAY SHORTWAVE AT
SOME POINT THIS WEEKEND...BUT CHANCES ARE LOW ENOUGH TO LEAVE OUT
TRYING TO PINPOINT TIMING THIS EARLY.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
639 AM CDT SUN AUG 12 2012
.UPDATE...
RADAR TRENDS AND SFC OBS INDICATE PRECIP WHEN IT REACHES THE
GROUND IS SPRINKLES WITH SOME HEAVIER SHRA. PER THE RAP MODEL THE
MAIN SHORTWAVE IS STILL WEST OF THE MISSOURI AND WILL MOVE THROUGH
LATE THIS AFTERNOON/TONIGHT. 06Z MODELS HAVE TRENDED THE SFC LOW
FURTHER SOUTH WHICH WAS EXPECTED. THIS SOUTHWARD TREND SUGGESTS
THE NORTHERN CWFA IS FAVORED FOR THE HEAVIER RAINFALL WITH A
POTENTIAL AXIS 30 MILES EITHER SIDE OF HWY 30.
OVERALL THE CURRENT FCST GENERALLY LOOKS TO BE ON TRACK WITH
PERHAPS SOME MINOR CHANGES TO REFLECT CURRENT TRENDS. LIFT TOOL
STILL SUGGESTS THE SOUTHERN HALF OF THE CWFA HAS THE BETTER TSRA
CHANCES LATE THIS AFTERNOON/EVENING. HOWEVER...ISOLD TSRA CANNOT
BE RULED OUT ACROSS THE NORTHERN HALF OF THE CWFA AS THE
DEFORMATION ZONE DEVELOPS. ..08..
&&
.AVIATION...
MAINLY VFR WX IS EXPECTED THROUGH 00Z/13. FM 21Z/12 TO 03Z/13
TSRA MAY DVLP WITH KBRL HAVING THE BEST CHANCE OF HAVING VCTS BUT
THIS WAS NOT INCLUDED IN THE 12Z TAFS. AFT 00Z/13 CONDITIONS WILL
DETERIORATE TO MVFR WITH POSSIBLE IFR VSBYS AS A STORM SYSTEM
MOVES THROUGH THE AREA. ..08..
&&
.PREV DISCUSSION... /ISSUED 325 AM CDT SUN AUG 12 2012/
SYNOPSIS...
06Z SFC ANALYSIS HAS A LOW NEAR K9V9 WITH OTHER LOWS NEAR KDDC AND
JUST NORTH OF KAMA. STRONG PRESSURE FALLS WERE ALONG THE MISSOURI
RIVER IN EASTERN NEBRASKA WHILE HIGH PRESSURE REMAINED ACROSS THE
WESTERN GREAT LAKES AND OHIO VALLEY. DEW POINTS WERE IN THE 40S AND
50S ACROSS THE GREAT LAKES WITH 50S AND LOW 60S IN THE PLAINS.
SHORT TERM...TODAY AND TONIGHT...
THE NEXT 24 HRS WILL BE INTERESTING AS THERE ARE INDICATIONS THAT A
NONLINEAR EVENT WILL OCCUR.
THE CURRENT RETURNS ON RADAR...MOST OF WHICH ARE SPRINKLES AT BEST
JUST WEST OF THE CWFA IS THE RESULT OF FORCING ON THE 315K THETA
SFC. WRF TRENDS WITH SOME INPUT FROM THE RAP INDICATE THIS FORCING
WILL WEAKEN AS IT ENCOUNTERS THE DRY AIR OVER THE AREA THROUGH
SUNRISE. THUS SPRINKLES OR VERY LIGHT RAIN IS EXPECTED GENERALLY
ALONG/WEST OF THE MISSISSIPPI.
AFTER SUNRISE...THE OVERALL FORCING CONTINUES TO WEAKEN INDICATING
AFTER A SHOT OF LIGHT RAIN/SPRINKLES EARLY THIS MORNING. THERE MAY
BE A BRIEF LULL FROM MID TO LATE MORNING. HOWEVER...CONDENSATION
PRESSURE DEFICITS ON THE 315K THETA SFC REMAIN LOW AND WITH AN
APPROACHING VORT MAX SOME SHRA/SPRINKLES WILL LIKELY PERSIST INTO
THE LATE MORNING HOURS.
THIS AFTERNOON AS THE MAIN SHORTWAVE APPROACHES PRECIPITATION WILL
BREAK OUT IN ERNEST ACROSS THE CWFA AS FORCING INCREASES. WRF
INDICATES EXTREMELY STRONG FORCING WILL DEVELOP BY MID TO LATE
AFTERNOON OVER THE NORTHERN HALF OF THE CWFA. CONCEPTUALLY WHAT IS
BEING SUGGESTED IS A DEFORMATION ZONE DEVELOPING. THE LIFT TOOL HAS
NEGATIVE THETA E LAPSE RATES DEVELOPING ACROSS THE SOUTHERN HALF OF
THE CWFA. THUS BY MID TO LATE AFTERNOON THERE SHOULD BE ISOLATED TO
SCATTERED TSRA ACROSS THE SOUTHERN HALF OF THE CWFA. WITH
INDICATIONS OF THE SYSTEM BEING NONLINEAR...ONE CANNOT RULE OUT
ISOLD TSRA ACROSS THE NORTHERN HALF OF THE CWFA. HOWEVER...ANY TSRA
THAT DEVELOP ACROSS THE NORTHERN HALF OF THE CWFA WILL HAVE A NARROW
WINDOW OF 3-6 HRS BEFORE THE FORCING SATURATES THE ATMOSPHERIC
COLUMN AND TURNS EVERYTHING TO STRATIFORM RAIN.
AS THE DEFORMATION ZONE MATURES TONIGHT RAIN WILL BECOME MORE
WIDESPREAD. RIGHT NOW IT APPEARS THAT AXIS OF THE DEFORMATION ZONE
SHOULD BE SOMEWHERE BETWEEN HWY 30 AND HWY 20 SUGGESTING THE
HEAVIEST RAIN WILL FALL THERE. AFTER MIDNIGHT FCST SOUNDINGS SHOW A
SATURATED ATMOSPHERE SO THE TSRA THREAT ACROSS THE SOUTHERN HALF OF
THE CWFA WILL END. JUST PRIOR TO SUNRISE THE OVERALL FORCING STARTS
TO WEAKEN SO THE AREAL COVERAGE/INTENSITY OF THE RAIN WILL BEGIN TO
DECREASE.
AS FOR RAINFALL AMOUNTS THROUGH SUNRISE MONDAY...THE NORTHERN HALF
OF THE CWFA SHOULD SEE GENERAL AMOUNTS OF ONE HALF TO ONE INCH WITH
POSSIBLY LOCALLY HIGHER AMOUNTS. THE SOUTH HALF OF THE CWFA SHOULD
SEE AMOUNTS BETWEEN ONE QUARTER AND ONE HALF INCH.
TEMPERATURES TODAY WILL BE INTERESTING. THERE IS THE POSSIBILITY
THAT THE FAR NORTHWEST PARTS OF THE CWFA MAY NOT GET OUT OF THE 60S
DUE TO CLOUDS/PRECIPITATION. THE FAR EAST/SOUTH PARTS OF THE CWFA
SHOULD SEE READINGS IN THE UPPER 70S TO LOWER 80S WITH LOW TO MID
70S ELSEWHERE. ..08..
LONG TERM...MONDAY THROUGH NEXT SATURDAY...
TIMING OF THE SIGNIFICANT COLD FRONT ON THURSDAY IS THE MAIN FORECAST
CHALLENGE.
OVERVIEW...
INITIALIZATION AND VERIFICATION IS AVERAGE WITH MOST SOLUTIONS TOO
DRY WITH SFC MOISTURE EXCEPT GFS 3-5 DEGREES TOO HIGH. VERIFICATION
AT 06Z SUPPORTS A 70/30 BLEND OF FORCING OF THE HI-RES ECMWF AND GFS
DAYS 2-7 WITH SOME REDUCTION IN GFS CONTAMINATED DEWPOINTS. THIS
SUPPORTS A MODERATE RAIN EVENT WITH PASSAGE OF THURSDAY COLD FRONT
AND GENERALLY MODERATE HUMIDITY`S.
MONDAY...SLIGHTLY LOWERED RAIN AMOUNTS IN MORNING WITH LIGHT TO LOW
END MODERATE AMOUNTS IN THE DECAYING DEFORMATION ZONE. LOCAL TOOLS
STILL SUGGEST MOST OR ALL SIGNIFICANT PRECIPITATION TO END BY NOON
WITH CLEARING SKIES FROM NORTHWEST TO EAST IN THE AFTERNOON. HIGH
TEMPERATURES TO REMAIN A CHALLENGE WITH MANY LOCATIONS ALONG AND
EAST OF THE MISSISSIPPI RIVER MAX VALUES AROUND 5 TO 6 PM. LOCAL
TOOLS AND TECHNIQUES CONTINUE TO SUPPORT A FEW HOURS OF SUNSHINE
SHOULD ALLOW FOR HIGHS TO REBOUND INTO THE MID TO UPPER 70S. MONDAY
NIGHT...KEPT LOWS IN THE UPPER 50S WITH A LIGHT NORTHWEST WIND.
STILL POTENTIAL FOR WINDS DECOUPLING TOWARD DAYBREAK ALLOWING FOR
SOME LOWER 50 DEGREE READINGS.
TUESDAY/WEDNESDAY...FAIR WITH VERY LITTLE CHANGE TO PREVIOUS FORECAST
EXCEPT LOWERING WEDNESDAY AM MINS. PATCHY FOG RISK ALSO REMAINS WITH
CALM WINDS AND GOOD DECOUPLING. SHOWERS AND STORMS WEDNESDAY EVENING
HAVE UPPED POPS TO HIGH CHANCE TO LIKELY.
THURSDAY...FRONT TO PASS DURING THE DAY. HIGH CHANCE POPS OF SHOWERS
AND STORMS WITH RISK OF SEVERE IN PM HOURS IF AREA TEMPERATURES CAN
RISE INTO THE MID/UPPER 80S WITH 60 DEWPOINTS AHEAD OF BOUNDARY.
NORTHWEST WINDS MAY BE GUSTY BEHIND FRONT. THURSDAY NIGHT...CLEARING
AND COLDER WITH MINS IN THE UPPER 40S TO MID 50S SUGGESTED.
FRIDAY AND SATURDAY...COOL AND COMFORTABLE LATE SUMMER WEATHER WITH
WELL BELOW NORMAL TEMPERATURES. LOCAL TOOLS SUPPORTS HIGHS UPPER 60S
TO UPPER 70S BOTH DAYS AND LOWS MOSTLY IN THE 40S WITH ISOLATED UPPER
30S POSSIBLE FOR LATER SHIFTS.
NICHOLS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
325 AM CDT SUN AUG 12 2012
.SYNOPSIS...
06Z SFC ANALYSIS HAS A LOW NEAR K9V9 WITH OTHER LOWS NEAR KDDC AND
JUST NORTH OF KAMA. STRONG PRESSURE FALLS WERE ALONG THE MISSOURI
RIVER IN EASTERN NEBRASKA WHILE HIGH PRESSURE REMAINED ACROSS THE
WESTERN GREAT LAKES AND OHIO VALLEY. DEW POINTS WERE IN THE 40S AND
50S ACROSS THE GREAT LAKES WITH 50S AND LOW 60S IN THE PLAINS.
&&
.SHORT TERM...TODAY AND TONIGHT...
THE NEXT 24 HRS WILL BE INTERESTING AS THERE ARE INDICATIONS THAT A
NONLINEAR EVENT WILL OCCUR.
THE CURRENT RETURNS ON RADAR...MOST OF WHICH ARE SPRINKLES AT BEST
JUST WEST OF THE CWFA IS THE RESULT OF FORCING ON THE 315K THETA
SFC. WRF TRENDS WITH SOME INPUT FROM THE RAP INDICATE THIS FORCING
WILL WEAKEN AS IT ENCOUNTERS THE DRY AIR OVER THE AREA THROUGH
SUNRISE. THUS SPRINKLES OR VERY LIGHT RAIN IS EXPECTED GENERALLY
ALONG/WEST OF THE MISSISSIPPI.
AFTER SUNRISE...THE OVERALL FORCING CONTINUES TO WEAKEN INDICATING
AFTER A SHOT OF LIGHT RAIN/SPRINKLES EARLY THIS MORNING. THERE MAY
BE A BRIEF LULL FROM MID TO LATE MORNING. HOWEVER...CONDENSATION
PRESSURE DEFICITS ON THE 315K THETA SFC REMAIN LOW AND WITH AN
APPROACHING VORT MAX SOME SHRA/SPRINKLES WILL LIKELY PERSIST INTO
THE LATE MORNING HOURS.
THIS AFTERNOON AS THE MAIN SHORTWAVE APPROACHES PRECIPITATION WILL
BREAK OUT IN ERNEST ACROSS THE CWFA AS FORCING INCREASES. WRF
INDICATES EXTREMELY STRONG FORCING WILL DEVELOP BY MID TO LATE
AFTERNOON OVER THE NORTHERN HALF OF THE CWFA. CONCEPTUALLY WHAT IS
BEING SUGGESTED IS A DEFORMATION ZONE DEVELOPING. THE LIFT TOOL HAS
NEGATIVE THETA E LAPSE RATES DEVELOPING ACROSS THE SOUTHERN HALF OF
THE CWFA. THUS BY MID TO LATE AFTERNOON THERE SHOULD BE ISOLATED TO
SCATTERED TSRA ACROSS THE SOUTHERN HALF OF THE CWFA. WITH
INDICATIONS OF THE SYSTEM BEING NONLINEAR...ONE CANNOT RULE OUT
ISOLD TSRA ACROSS THE NORTHERN HALF OF THE CWFA. HOWEVER...ANY TSRA
THAT DEVELOP ACROSS THE NORTHERN HALF OF THE CWFA WILL HAVE A NARROW
WINDOW OF 3-6 HRS BEFORE THE FORCING SATURATES THE ATMOSPHERIC
COLUMN AND TURNS EVERYTHING TO STRATIFORM RAIN.
AS THE DEFORMATION ZONE MATURES TONIGHT RAIN WILL BECOME MORE
WIDESPREAD. RIGHT NOW IT APPEARS THAT AXIS OF THE DEFORMATION ZONE
SHOULD BE SOMEWHERE BETWEEN HWY 30 AND HWY 20 SUGGESTING THE
HEAVIEST RAIN WILL FALL THERE. AFTER MIDNIGHT FCST SOUNDINGS SHOW A
SATURATED ATMOSPHERE SO THE TSRA THREAT ACROSS THE SOUTHERN HALF OF
THE CWFA WILL END. JUST PRIOR TO SUNRISE THE OVERALL FORCING STARTS
TO WEAKEN SO THE AREAL COVERAGE/INTENSITY OF THE RAIN WILL BEGIN TO
DECREASE.
AS FOR RAINFALL AMOUNTS THROUGH SUNRISE MONDAY...THE NORTHERN HALF
OF THE CWFA SHOULD SEE GENERAL AMOUNTS OF ONE HALF TO ONE INCH WITH
POSSIBLY LOCALLY HIGHER AMOUNTS. THE SOUTH HALF OF THE CWFA SHOULD
SEE AMOUNTS BETWEEN ONE QUARTER AND ONE HALF INCH.
TEMPERATURES TODAY WILL BE INTERESTING. THERE IS THE POSSIBILITY
THAT THE FAR NORTHWEST PARTS OF THE CWFA MAY NOT GET OUT OF THE 60S
DUE TO CLOUDS/PRECIPITATION. THE FAR EAST/SOUTH PARTS OF THE CWFA
SHOULD SEE READINGS IN THE UPPER 70S TO LOWER 80S WITH LOW TO MID
70S ELSEWHERE. ..08..
.LONG TERM...MONDAY THROUGH NEXT SATURDAY...
TIMING OF THE SIGNIFICANT COLD FRONT ON THURSDAY IS THE MAIN FORECAST
CHALLENGE.
OVERVIEW...
INITIALIZATION AND VERIFICATION IS AVERAGE WITH MOST SOLUTIONS TOO
DRY WITH SFC MOISTURE EXCEPT GFS 3-5 DEGREES TOO HIGH. VERIFICATION
AT 06Z SUPPORTS A 70/30 BLEND OF FORCING OF THE HI-RES ECMWF AND GFS
DAYS 2-7 WITH SOME REDUCTION IN GFS CONTAMINATED DEWPOINTS. THIS
SUPPORTS A MODERATE RAIN EVENT WITH PASSAGE OF THURSDAY COLD FRONT
AND GENERALLY MODERATE HUMIDITY`S.
MONDAY...SLIGHTLY LOWERED RAIN AMOUNTS IN MORNING WITH LIGHT TO LOW
END MODERATE AMOUNTS IN THE DECAYING DEFORMATION ZONE. LOCAL TOOLS
STILL SUGGEST MOST OR ALL SIGNIFICANT PRECIPITATION TO END BY NOON
WITH CLEARING SKIES FROM NORTHWEST TO EAST IN THE AFTERNOON. HIGH
TEMPERATURES TO REMAIN A CHALLENGE WITH MANY LOCATIONS ALONG AND
EAST OF THE MISSISSIPPI RIVER MAX VALUES AROUND 5 TO 6 PM. LOCAL
TOOLS AND TECHNIQUES CONTINUE TO SUPPORT A FEW HOURS OF SUNSHINE
SHOULD ALLOW FOR HIGHS TO REBOUND INTO THE MID TO UPPER 70S. MONDAY
NIGHT...KEPT LOWS IN THE UPPER 50S WITH A LIGHT NORTHWEST WIND.
STILL POTENTIAL FOR WINDS DECOUPLING TOWARD DAYBREAK ALLOWING FOR
SOME LOWER 50 DEGREE READINGS.
TUESDAY/WEDNESDAY...FAIR WITH VERY LITTLE CHANGE TO PREVIOUS FORECAST
EXCEPT LOWERING WEDNESDAY AM MINS. PATCHY FOG RISK ALSO REMAINS WITH
CALM WINDS AND GOOD DECOUPLING. SHOWERS AND STORMS WEDNESDAY EVENING
HAVE UPPED POPS TO HIGH CHANCE TO LIKELY.
THURSDAY...FRONT TO PASS DURING THE DAY. HIGH CHANCE POPS OF SHOWERS
AND STORMS WITH RISK OF SEVERE IN PM HOURS IF AREA TEMPERATURES CAN
RISE INTO THE MID/UPPER 80S WITH 60 DEWPOINTS AHEAD OF BOUNDARY.
NORTHWEST WINDS MAY BE GUSTY BEHIND FRONT. THURSDAY NIGHT...CLEARING
AND COLDER WITH MINS IN THE UPPER 40S TO MID 50S SUGGESTED.
FRIDAY AND SATURDAY...COOL AND COMFORTABLE LATE SUMMER WEATHER WITH
WELL BELOW NORMAL TEMPERATURES. LOCAL TOOLS SUPPORTS HIGHS UPPER 60S
TO UPPER 70S BOTH DAYS AND LOWS MOSTLY IN THE 40S WITH ISOLATED UPPER
30S POSSIBLE FOR LATER SHIFTS.
NICHOLS
&&
.AVIATION... /ISSUED 1139 PM CDT SAT AUG 11 2012/
A RIDGE OF HIGH PRESSURE OVER EASTERN IA LATE THIS EVENING WILL MOVE
EAST AS A DEVELOPING LOW PRESSURE OVER THE NORTHERN PLAINS...REACHES
THE MID MISSOURI RIVER VALLEY BY MID-DAY SUNDAY...THEN DROPS SOUTH
INTO NORTHERN MO BY SUNDAY EVENING. GENERALLY VFR CIGS/VSBYS ARE
EXPECTED THROUGH MUCH OF THE FORECAST PERIOD. LIGHT RAIN AND
SPRINKLES SPREADING EAST AHEAD OF THE SURFACE LOW SHOULD PUSH INTO
EASTERN IA EARLY SUNDAY MORNING AND MAY REACH THE MISSISSIPPI RIVER
BY NOON. THE RAIN WILL BE RUNNING INTO A DRY AIRMASS SO CIGS AND
VSBYS ARE EXPECTED TO STAY VFR THROUGH 00Z MONDAY. AFTER 00Z
CONDITIONS WILL DETERIORATE TO MVFR AS THE RAIN CONTINUES TO SPREAD
OVER THE AREA AND THE LOW LEVELS BEGIN TO SATURATE.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
08/NICHOLS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
625 PM MDT MON AUG 13 2012
.UPDATE...
ISSUED AT 616 PM MDT MON AUG 13 2012
JUST COMPLETED AN UPDATE. SIGNIFICANTLY RAISED POPS IN THE
SOUTHWEST HALF OF THE AREA. SHORTWAVE TROUGH AND RIGHT REAR
QUADRANT OF JET ARE INCREASING THE COVERAGE OF STORMS FURTHER EAST
THAN WHAT WAS PREVIOUSLY DEPICTED. THE HRRR IS CATCHING THE HOURLY
TRENDS ON THE PRECIPITATION VERY WELL AND IS MIRRORED CLOSELY BY
THE 6 HOUR AMOUNTS SHOWN BY THE SREF AND ECMWF. THIS AREA MAKES
VERY GOOD SENSE CONSIDERING THE TRENDS AND THE LIFTING MECHANISMS.
SO FOLLOWED CLOSELY THOSE MODEL DEPICTIONS THROUGH THIS EVENING.
OTHERWISE...INCREASED CLOUD COVER SIGNIFICANTLY THROUGH THE
EVENING. WILL MONITOR TRENDS ON EVERYTHING ELSE THROUGH THE
EVENING. MESOSCALE AFFECTS WILL NO DOUBT WREAK HAVOC ON REMAINING
PARAMETERS THROUGH THE NIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 140 PM MDT MON AUG 13 2012
UPPER FLOW WILL BE NORTHWEST TONIGHT/TUESDAY. A SHORTWAVE WILL COME
THROUGH THE FLOW TONIGHT. SUBSIDENCE WILL FOLLOW BEHIND THE WAVE ON
TUESDAY. SURFACE HIGH PRESSURE WILL BE OVER THE AREA TONIGHT. LOW
PRESSURE WILL BE OVER EASTERN WYOMING/NORTHEAST COLORADO TUESDAY.
DYNAMICS FROM THE INCOMING SHORTWAVE TONIGHT ARE SHOWN TO SLIDE
SOUTHEAST FROM EASTERN COLORADO INTO THE SOUTHERN FA. THIS IS WHERE
THE BEST MOISTURE IS AS WELL. PLAN TO GO WITH CHANCE POPS FOR THIS
AREA AND SLIGHT CHANCE POPS WHERE THERE IS LESS MOISTURE AND
FORCING. SUBSIDENCE WILL KEEP POPS NIL TUESDAY.
MIN TEMPERATURES TONIGHT WILL BE WARMER THAN LAST NIGHT AS COOLER
TEMPERATURES HAVE MOVED PAST THE FA AND SOUTH WINDS WILL MAINTAIN
GOOD MIXING OVERNIGHT. EXPECT READINGS IN THE UPPER 50S/LOWER 60S.
MAX TEMPERATURES TUESDAY WILL RISE INTO THE LOWER 90S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 250 PM MDT MON AUG 13 2012
THE FIRST SIGNIFICANT WEATHER FEATURE TO IMPACT THE AREA DURING
THIS PERIOD WILL BE A STRONG UPPER SHORT WAVE TROUGH NOW OVER
BRITISH COLUMBIA AS SEEN IN WATER VAPOR IMAGERY. THIS TROUGH WILL
MOVE SOUTHEAST AND SWEEP ACROSS THE C-N PLAINS WED-WED NIGHT. AT
THE SURFACE A STRONG COLD FRONT WILL MOVE RAPIDLY SOUTH ACROSS THE
FORECAST AREA WEDNESDAY EVENING AND WILL CLEAR THE AREA LATE
WEDNESDAY NIGHT. THESE FEATURES WILL GIVE AN OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS MAINLY WEDNESDAY NIGHT. MUCH COLDER AIR
WILL SETTLE INTO THE REGION FOR THURSDAY AND FRIDAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S.
BOTH THE EC AND GFS SUGGEST A MODERATELY STRONG NORTHWEST FLOW
ALOFT FOR THE REMAINDER OF THE WEEK AND THROUGH THE WEEKEND. THE
EC IS MOSTLY DRY WITH THIS PATTERN BUT THE GFS SUGGESTS THE
POTENTIAL FOR SEVERAL EPISODES OF PRECIPITATION. BOTH MODELS HINT
AT SEVERAL WEAK...FAST-MOVING SHORT WAVE TROUGHS SLIDING SOUTHEAST
THROUGH THE FLOW BUT TIMING WILL BE DIFFICULT. LOW POPS ARE
INCLUDED IN THE EXTENDED FORECAST AS A RESULT. ANY CONVECTION
WHICH INITIATES ON THE CHEYENNE RIDGE WOULD MOVE INTO THE
AREA...AIDED BY SOUTHEAST SURFACE FLOW WHICH WILL ENHANCE STORM
INFLOW TO KEEP CONVECTION GOING FOR A FEW HOURS BEFORE
DISSIPATION.
TEMPERATURES OVER THE WEEKEND WILL RETURN TO CLOSER TO NORMAL
VALUES BUT THE EXTREME HEAT HAS ABATED FOR AT LEAST THE NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 541 PM MDT MON AUG 13 2012
COMPLICATED SET OF TAFS ESPECIALLY FOR KGLD. EVEN WITH THE
THUNDERSTORMS IN PROGRESS...MODELS STILL NOT IN COMPLETE AGREEMENT
AS TO WHERE TO PUT THE PRECIPITATION. BASED ON LATEST TRENDS FROM
OBSERVATIONAL DATA...THE HRRR IS DOING THE BEST RIGHT AND DOES
BRING IN A CLUSTER OF STORMS THROUGH THE EVENING. SO HAVE INSERTED
THUNDERSTORMS ACROSS AT KGLD DURING THIS TIME. BASED ON WHAT HAVE
SEEN UPSTREAM...IT WILL BE POSSIBLE THAT MVFR VISIBILITIES WILL
OCCUR AT KGLD. MODELS INDICATING LOW CLOUDS AFTER 06Z AT KGLD.
WILL LET THE THUNDERSTORM SITUATION EVOLVE BEFORE BECOMING MORE
PESSIMISTIC BUT DID INSERT A SCATTERED LOW DECK. FOR KMCK IT LOOKS
LIKE THUNDERSTORMS WILL NOT AFFECT THE TAF SITE AT THIS TIME.
HOWEVER...WILL TO MONITOR TO MAKE ADJUSTMENTS AS NEEDED. IF NO
THUNDERSTORMS OCCUR AT KMCK...CONDITIONS WILL BE VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...FS
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
549 PM MDT MON AUG 13 2012
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 140 PM MDT MON AUG 13 2012
UPPER FLOW WILL BE NORTHWEST TONIGHT/TUESDAY. A SHORTWAVE WILL COME
THROUGH THE FLOW TONIGHT. SUBSIDENCE WILL FOLLOW BEHIND THE WAVE ON
TUESDAY. SURFACE HIGH PRESSURE WILL BE OVER THE AREA TONIGHT. LOW
PRESSURE WILL BE OVER EASTERN WYOMING/NORTHEAST COLORADO TUESDAY.
DYNAMICS FROM THE INCOMING SHORTWAVE TONIGHT ARE SHOWN TO SLIDE
SOUTHEAST FROM EASTERN COLORADO INTO THE SOUTHERN FA. THIS IS WHERE
THE BEST MOISTURE IS AS WELL. PLAN TO GO WITH CHANCE POPS FOR THIS
AREA AND SLIGHT CHANCE POPS WHERE THERE IS LESS MOISTURE AND
FORCING. SUBSIDENCE WILL KEEP POPS NIL TUESDAY.
MIN TEMPERATURES TONIGHT WILL BE WARMER THAN LAST NIGHT AS COOLER
TEMPERATURES HAVE MOVED PAST THE FA AND SOUTH WINDS WILL MAINTAIN
GOOD MIXING OVERNIGHT. EXPECT READINGS IN THE UPPER 50S/LOWER 60S.
MAX TEMPERATURES TUESDAY WILL RISE INTO THE LOWER 90S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 250 PM MDT MON AUG 13 2012
THE FIRST SIGNIFICANT WEATHER FEATURE TO IMPACT THE AREA DURING
THIS PERIOD WILL BE A STRONG UPPER SHORT WAVE TROUGH NOW OVER
BRITISH COLUMBIA AS SEEN IN WATER VAPOR IMAGERY. THIS TROUGH WILL
MOVE SOUTHEAST AND SWEEP ACROSS THE C-N PLAINS WED-WED NIGHT. AT
THE SURFACE A STRONG COLD FRONT WILL MOVE RAPIDLY SOUTH ACROSS THE
FORECAST AREA WEDNESDAY EVENING AND WILL CLEAR THE AREA LATE
WEDNESDAY NIGHT. THESE FEATURES WILL GIVE AN OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS MAINLY WEDNESDAY NIGHT. MUCH COLDER AIR
WILL SETTLE INTO THE REGION FOR THURSDAY AND FRIDAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S.
BOTH THE EC AND GFS SUGGEST A MODERATELY STRONG NORTHWEST FLOW
ALOFT FOR THE REMAINDER OF THE WEEK AND THROUGH THE WEEKEND. THE
EC IS MOSTLY DRY WITH THIS PATTERN BUT THE GFS SUGGESTS THE
POTENTIAL FOR SEVERAL EPISODES OF PRECIPITATION. BOTH MODELS HINT
AT SEVERAL WEAK...FAST-MOVING SHORT WAVE TROUGHS SLIDING SOUTHEAST
THROUGH THE FLOW BUT TIMING WILL BE DIFFICULT. LOW POPS ARE
INCLUDED IN THE EXTENDED FORECAST AS A RESULT. ANY CONVECTION
WHICH INITIATES ON THE CHEYENNE RIDGE WOULD MOVE INTO THE
AREA...AIDED BY SOUTHEAST SURFACE FLOW WHICH WILL ENHANCE STORM
INFLOW TO KEEP CONVECTION GOING FOR A FEW HOURS BEFORE
DISSIPATION.
TEMPERATURES OVER THE WEEKEND WILL RETURN TO CLOSER TO NORMAL
VALUES BUT THE EXTREME HEAT HAS ABATED FOR AT LEAST THE NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 541 PM MDT MON AUG 13 2012
COMPLICATED SET OF TAFS ESPECIALLY FOR KGLD. EVEN WITH THE
THUNDERSTORMS IN PROGRESS...MODELS STILL NOT IN COMPLETE AGREEMENT
AS TO WHERE TO PUT THE PRECIPITATION. BASED ON LATEST TRENDS FROM
OBSERVATIONAL DATA...THE HRRR IS DOING THE BEST RIGHT AND DOES
BRING IN A CLUSTER OF STORMS THROUGH THE EVENING. SO HAVE INSERTED
THUNDERSTORMS ACROSS AT KGLD DURING THIS TIME. BASED ON WHAT HAVE
SEEN UPSTREAM...IT WILL BE POSSIBLE THAT MVFR VISIBILITIES WILL
OCCUR AT KGLD. MODELS INDICATING LOW CLOUDS AFTER 06Z AT KGLD.
WILL LET THE THUNDERSTORM SITUATION EVOLVE BEFORE BECOMING MORE
PESSIMISTIC BUT DID INSERT A SCATTERED LOW DECK. FOR KMCK IT LOOKS
LIKE THUNDERSTORMS WILL NOT AFFECT THE TAF SITE AT THIS TIME.
HOWEVER...WILL TO MONITOR TO MAKE ADJUSTMENTS AS NEEDED. IF NO
THUNDERSTORMS OCCUR AT KMCK...CONDITIONS WILL BE VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...FS
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS WICHITA KS
351 PM CDT SUN AUG 12 2012
.DISCUSSION...
SHORT RANGE...TONIGHT THROUGH TUESDAY
IN THE VERY SHORT TERM...SMALL CU BEGINNING TO DEVELOP ACROSS EXTREME
EASTERN KANSAS DUE TO DIURNAL MIXING AND WEAK ISENTROPIC LIFT...WITH
ADDITIONAL COLD CORE CU MOVING INTO NORTHEAST KANSAS. RIGHT
NOW...CU DEVELOPMENT IS NOT OVERLY IMPRESSIVE...HOWEVER SPC MESO
GRAPHICS INDICATED UNCAPPED ENVIRONMENT ACROSS SOUTHEAST KANSAS
AHEAD OF FRONTAL BOUNDARY CURRENTLY BISECTING CWA. HRRR AND RUC
BOTH GIVING INFINISMAL CHANCE OF THUNDERSTORMS BRUSHING EXTREME
SOUTHEASTERN CWA BETWEEN 21/12 AND 01/13...THUS WILL MAINTAIN LOW
CHANCE PO0PS IN THIS AREA. THE REST OF THE CWA WILL REMAIN DRY
OVERNIGHT.
NEXT CHANCE OF PRECIPITATION COMES LATE MONDAY NIGHT INTO TUESDAY
AS MCS ROLLS OFF LEE SLOPE OF ROCKIES. MITIGATING FACTOR FOR
COVERAGE WILL BE LOW LEVEL MOISTURE AS FRONT CURRENTLY MOVING
THROUGH PLAINS WILL SCOUR MOISTURE. ISENTROPIC LIFT/MOIST ADVECTION
IMPROVES BETWEEN 06 AND 12 UTC ON TUESDAY...SO WILL TREND POPS UP IN
THIS TIME PERIOD. DISCPREPANCY AS WELL ON EXACT TRACK AND SOUTHERN
DEVELOPMENT OF STORMS BETWEEN SHORT TERM MODELS AND ENSEMBLES...WILL
LEAN TOWARD EC SOLUTION WHICH KEEPS BULK OF PRECIP IN CLOSE
PROXIMITY TO BETTER QG AND ISENTROPIC FORCING. MCS THAT ROLLS
THROUGH APPEARS TO LEAVE BOUNDARIES AROUND THAT WILL ALLOW
ADDITIONAL DEVELOPMENT TUES AFTERNOON EVENING AS RRQ OF UPPER LEVEL
JET DIVES FROM CENTRAL PLAINS INTO LOWER MISSISSIPPI VALLEY.
OVERALL...TRENDED LOWER ON QPF AS WELL GIVEN DROUGHT TRENDS.
TEMPERATURES WILL BE PLEASANT...WITH NARY A 100 DEGREE IN SITE FOR
SOME TIME. LARGE SCALE TROUGH ACROSS EASTERN TWO THIRDS OF NATION
WILL KEEP HEAT AT BAY FOR A WHILE. NORTH TO NORTHEAST FLOW MONDAY
WILL KEEP TEMPERATURES BELOW NORMAL FOR THE FIRST TIME IN A LONG
TIME. THAT TREND CONTINUES THROUGH THE SHORT TERM...AS CLOUDS AND
CONVECTION WILL KEEP THINGS A LITTLE COOLER ON TUESDAY AS WELL.
DRYNESS OF SOIL WILL ALLOW FOR SUPERADIABATIC HEATING...SO WILL
TREND TOWARD HIGHER END OF GUIDANCE FOR THE MOST PART.
MEDIUM RANGE...WEDNESDAY THROUGH SATURDAY
ANOTHER ROUND OF SHOWERS AND STORMS POSSIBLE WEDNESDAY NIGHT INTO
THURSDAY AS POTENT SHORT WAVE MOVING THROUGH NORTHERN STREAM DRIVES
ANOTHER FRONTAL SYSTEM THROUGH CWA. MOISTURE AGAIN WILL BE
LIMITED...SO LITTLE SUSPECT OF GREATER POPS PROBABILITIES BEING
GENERATED BY GEFS AND CONSENSUS BLENDS. GIVEN RECENT DROUGHT
TRENDS...TONED PROBABILITIES BACK A LITTLE. AFTER
THURSDAY...SURFACE RIDGING WILL BE IN PLACE THROUGH THE EARLY
WEEKEND...THEN UPPER RIDGING BEGINS TO BUILD BACK INTO CENTRAL
PLAINS AS EASTERN U.S. LARGE SCALE TROUGH EDGES EAST. THERE IS AN
OUTSIDE CHANCE OF CONVECTION RETURNING LATE IN THE WEEKEND DUE TO
ENHANCED RETURNED FLOW...BUT WILL LEAVE FORECAST DRY FOR NOW.
TEMPERATURES RETURN TO NORMAL ON WEDNESDAY HEAD OF AFOREMENTIONED
FRONTAL BOUNDARY...THEN ANOTHER SEVERAL DAYS OF BELOW NORMAL
TEMPERATURES IN STORE FOR THE CWA IN TERMS OF MAXIMUMS AND
MINIMUMS. USED A BLEND OF CONSENSUS FOR HIGHS AND GFS40 FOR
MINS...WHICH HAS BEEN DOING AMAZINGLY WELL GIVEN HOW POORLY IT HAS
HANDLED MAX TEMPERATURES OF LATE.
SF
&&
.PREV DISCUSSION... /ISSUED 1222 PM CDT SUN AUG 12 2012/
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VFR CONDITIONS EXPECTED TO PREVAIL THRU THE FORECAST VALID PERIOD.
ISOLATED CONVECTION IS EXPECTED ALONG A COLD FRONT LATE THIS
AFTERNOON...WITH A FEW STORMS POSSIBLY AFFECTING SOUTHEAST KANSAS.
FRONTAL TIMING SUGGESTS THIS ACTIVITY WILL BE JUST SOUTH OF KCNU
THOUGH INCLUDED A VCTS FOR A FEW HOURS AT START OF FORECAST.
OTHERWISE GUSTY NORTH-NORTHWEST WINDS BEHIND THE FRONT WILL
DIMINISH THIS EVENING...ONLY TO PICK UP AGAIN AFTER SUNRISE ON
MONDAY MORNING ACROSS THE AREA.
KED
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 61 90 62 87 / 10 0 20 30
HUTCHINSON 59 87 62 88 / 10 0 30 30
NEWTON 59 86 60 88 / 10 0 20 30
ELDORADO 58 89 58 88 / 10 0 10 30
WINFIELD-KWLD 62 91 62 88 / 10 0 10 30
RUSSELL 58 87 60 88 / 0 0 30 50
GREAT BEND 59 87 61 88 / 0 0 30 40
SALINA 58 87 61 89 / 10 0 30 40
MCPHERSON 58 87 62 88 / 10 0 20 30
COFFEYVILLE 62 93 60 88 / 20 0 0 30
CHANUTE 60 89 58 88 / 30 0 0 30
IOLA 59 88 58 87 / 30 10 0 30
PARSONS-KPPF 61 90 60 88 / 20 0 0 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1130 PM MDT SAT AUG 11 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 108 PM MDT SAT AUG 11 2012
PRE-FRONTAL TROUGH AND ASSOCIATED WIND SHIFT LINE HAS MOVED INTO
THE FAR WESTERN PART OF THE FORECAST AREA. WATER VAPOR IMAGERY
SHOWS SHORT WAVE TROUGH CURRENTLY MOVING ACROSS SOUTHEAST WYOMING.
ALTHOUGH THE STRONGEST PART OF THE WAVE WILL BE NORTH OF FORECAST
AREA...THERE WILL BE ENOUGH DIFFERENTIAL CYCLONIC VORTICITY
ADVECTION TO PRODUCE SCATTERED CONVECTION. LATEST GFS IS SLIGHTLY
SLOWER WITH FEATURE...BUT STILL ON TRACK FOR SCATTERED PRECIPITATION
CHANCES TONIGHT.
KFTG RADAR IS SHOWING SIGNS OF CONVECTIVE DEVELOPMENT NORTH OF KLIC.
LATEST RUN OF THE HRRR MODEL CONTINUES TO PRODUCE SCATTERED
THUNDERSTORMS OVER EASTERN COLORADO FROM 21Z-23Z...WITH STORMS
MOVING OVER THE REST OF THE AREA AFTER THAT TIME. HRRR MAY BE
OVERDONE WITH THE AMOUNT OF COVERAGE...BUT HAS THE GENERAL IDEA.
BOTH THE NAM/GFS ALSO SHOW CONVECTION ADVECTING OVER MOST OF THE
AREA. THEREFORE...WILL CONTINUE WITH SCATTERED POPS THROUGH
MIDNIGHT. AS MENTIONED EARLIER...LOW LEVEL SHEAR IS MINIMAL.
SOUNDING PROFILES...HOWEVER..HAVE AN INVERTED-V SIGNATURE.
SO...SOME CONVECTIVE WIND GUSTS WILL APPROACH SEVERE LIMITS...THOUGH
WOULD LIKE TO SEE A LITTLE MORE IMPRESSIVE DOWNDRAFT CAPE. 700 MB
THETA/E AXIS WILL EXTEND FROM GOODLAND TO HASTINGS THIS EVENING...SO
A FEW STORMS MAY PRODUCE BRIEF HEAVY RAIN.
COLD FRONT AND DRIER AIR WILL MOVE ACROSS THE AREA AFTER 06Z.
1000/500 MB THICKNESS VALUES DROP...BUT NOT IMPRESSIVELY. WILL
ONLY COOL TEMPERATURES SEVERAL DEGREES TONIGHT AND SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 PM MDT SAT AUG 11 2012
SUNDAY NIGHT-MONDAY NIGHT...DRY SUNDAY NIGHT UNDER HIGH PRESSURE
WITH JUST A FEW CLOUDS. LOWS IN THE 50S. ON MONDAY A WEATHER
DISTURBANCE ENTERS THE SOUTHWEST AND WESTERN PORTION OF THE FORECAST
AREA MOVING EAST/SOUTHEAST ACROSS THE REMAINDER OF THE AREA MONDAY
NIGHT. THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
WITH ITS PASSAGE. HIGH TEMPERATURES MONDAY IN THE MID 80S TO AROUND
90 WITH OVERNIGHT LOWS MONDAY NIGHT IN THE UPPER 50S TO LOW 60S.
TUESDAY...DRY WEATHER EXPECTED. NOT REAL CONFIDENT IN PRECIP CHANCES
TUESDAY NIGHT GIVEN RATHER POOR MOISTURE AVAILABILITY ACROSS THE
AREA. HIGHS IN THE LOW TO MID 90S.
WEDNESDAY...COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASES THROUGH
WEDNESDAY NIGHT AS AN UPPER LEVEL TROUGH AND COLD FRONT MOVE ACROSS
THE AREA. HIGHS IN THE UPPER 80S TO LOW 90S WITH LOWS WEDNESDAY
NIGHT IN THE UPPER 50S TO MID 60S.
THURSDAY...MAY SEE SOME LINGERING PRECIPITATION DURING THE DAY
BEFORE MOISTURE AVAILABILITY DECREASES AS SFC HIGH MOVES IN THURSDAY
NIGHT. HIGHS IN THE MID 70S TO LOW 80S. OVERNIGHT LOWS IN THE MID TO
UPPER 50S.
FRIDAY-SATURDAY...UPPER RIDGE REBUILDS ACROSS THE INTERMOUNTAIN WEST
THROUGH THE PERIOD. MOISTURE AVAILABILITY FOR PRECIPITATION LOOKS
PRETTY LOW AS IS CONFIDENCE IN PRECIPITATION CHANCES. HIGHS ON
FRIDAY IN THE LOW 80S...WARMING INTO THE UPPER 80S TO AROUND 90.
OVERNIGHT LOWS IN THE MID 50S TO AROUND 60.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1129 PM MDT SAT AUG 11 2012
VFR EXPECTED AT BOTH KGLD AND KMCK THROUGH THE VALID TAF PERIOD.
THUNDERSTORM CHANCES HAVE ENDED FOR TONIGHT. A COLD FRONT WILL
MOVE THROUGH THE REGION OVERNIGHT WITH SURFACE WINDS SHIFTING TO
THE NORTHWEST...OCCASIONALLY GUSTY THROUGH SUNDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...MENTZER
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS CARIBOU ME
636 PM EDT SUN AUG 12 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OF THE REGION OVERNIGHT. A WEAK RIDGE
OF HIGH PRESSURE WILL MOVE ACROSS THE AREA MONDAY INTO TUESDAY THEN
ANOTHER LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH
ON WEDNESDAY FROM CENTRAL CANADA.
&&
.NEAR TERM /THROUGH MONDAY/...
UPDATE...MADE SOME ADJUSTMENTS TO POP,WX, AND QPF GRIDS BASED ON
CURRENT RADAR AND OBSERVATIONS. THE MAIN CHANGE WAS TO UP QPF AND
POPS OVER WESTERN SECTIONS FOR THIS EVENING AS AN AREA OF SHOWERS
WITH SOME ISOLATED THUNDERSTORMS HAS FORMED RIGHT ALONG THE QUEBEC
BORDER. THIS AREA SHOULD SLOWLY SHIFT EAST THROUGH THIS EVENING.
PREVIOUS DISCUSSION... LOW PRESSURE WILL MOVE INTO CENTRAL QUEBEC
PROVINCE TONIGHT THEN WEAKEN MONDAY. HAVE BASED POPS INTO THIS
EVENING ON RUC13 THEN TRANSITION TO THE A BLEND OF THE
NAM12...GFS40...CMCREG AND ECMWF. FOR TEMPERATURE AND DEW POINT
HAVE USED THE GMOS. QPF BASED ON THE A BLEND OF THE NAM12 AND
GFS40. ATMOSPHERE LOOKS STABLE OVER EASTERN MAINE SO WILL REMOVE
MENTION OF THUNDER THIS EVENING AFTER 0000Z.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LGT WINDS WITH A WEAK SFC PRES GRAD AND AT LEAST PARTIALLY CLR
SKIES MON NGT ACROSS THE FA SHOULD ALLOW FOR ENOUGH RADIATIONAL
COOLING TO RESULT IN PATCHY VALLEY FOG LATE IN THE PD.
MOST IF NOT ALL OF THIS FOG SHOULD BURN OFF SHORTLY AFT SUNRISE
TUE ALLOWING FOR INTERVALS OF CLDS AND SUNSHINE ACROSS THE FA ALG
WITH WARM AFTN HI TEMPS MSLY IN THE LOWER TO MID 80S...XCPT COOLER
ALG THE IMMEDIATE COAST. THE STRENGTH OF THE S/WV RIDGE ALF SHOULD
MSLY PREVENT TSTM DEVELOPMENT...SO WE LOWERED POPS TO THE SLGT CHC
CAT MAINLY ACROSS NRN/WRN PTNS OF THE FA FOR THE AFTN AND EVE HRS.
MEANWHILE...A STRONGER S/WV MOVG E FROM CNTRL CAN WILL BEGIN TO
BRING HI/MID CLDS TO THE FA AS ERLY AS LATE TUE NGT. DUE TO THE
SLIGHTLY FASTER ARRIVAL OF THE S/WV THAN SHOWN IN MODELS YSTDY
ATTM...WE HELD OFF ON ANY FOG MENTION IN OUR FA LATE TUE NGT FOR
NOW. OTHERWISE...SHWRS COULD ARRIVE INTO WRN PTNS OF THE FA WED
MORN AND INTENSIFY TO TSTMS OVR CNTRL AND ERN PTNS OF THE FA WED
AFTN WITH MAX POTENTIAL AFTN SB CAPES OF 1000-1500 J/KG BASED ON
SREF PROJECTIONS WITH OPNL GFS/NAM PROJECTIONS UPWARDS OF 1500-
2000 J/KG LIKELY TO HI GIVEN CURRENT PROJECTIONS OF LMTD SUNSHINE
ON WED. FOR THIS REASON...WE WILL NOT BE INCLUDING ANY ENHANCED
TSTM WORDING IN OUR GRIDS FOR WED AFTN ATTM. HOWEVER...CONSENSUS
OF DIFFERENT MODEL 6 HRLY QPF PROJECTIONS FAVORED GOING UP TO LOW
CAT POPS SPCLY W...N AND CNTRL PTNS OF THE FA WED AFTN WITH LIKELY
POPS OVR DOWNEAST AREAS AND CHC POPS OVR THE WATERS.
AFT MILD OVRNGT LOWS TUE NGT...HI TEMPS WED WILL LIKELY BE HELD
BACK BY CLD CVR...SPCLY OVR NRN AND WRN PTNS OF THE REGION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UNSETTLED CONDITIONS WILL CONTINUE THROUGH THE END OF THE WEEK INTO
THE WEEKEND AS THE REGION REMAINS UNDER THE INFLUENCE OF AN UPPER
TROUGH. RIGHT OFF THE BAT, THE FORECAST MODELS ARE HAVING TROUBLE
AGREEING ON THE HANDLING OF THIS TROUGH AND THE SHORTWAVES THAT WILL
TRAVERSE AROUND ITS PERIPHERY. WHILE THE GFS AND ECMWF BOTH HAVE A
CLOSED SHORTWAVE IN THE VICINITY OF SOUTHERN WEDNESDAY EVENING, THE
GFS OPENS THE WAVE UP WEDNESDAY NIGHT AND SHUNTS IT EASTWARD
THURSDAY. THIS ALLOWS A BRIEF RIDGE TO BUILD OVER NEW ENGLAND
THURSDAY INTO EARLY FRIDAY, MEANING DRY WEATHER FOR THAT TIME
PERIOD. THE GFS THEN PRODUCES SEVERAL ROUNDS OF SHOWERS OVER THE
STATE THROUGH THE WEEKEND AS WAVES MOVE THROUGH THE SOUTHWEST FLOW
ALOFT AHEAD OF THE MAIN UPPER LOW. MEANWHILE, THE ECMWF CUTS OFF THE
FIRST UPPER SHORTWAVE WEDNESDAY NIGHT AND THEN SLOWLY MOVES IT EAST
TO NOVA SCOTIA BY SATURDAY MORNING. ONLY THEN DOES IT SHOW SOME
RIDGING AT THE SURFACE AND ALOFT, FRIDAY NIGHT THROUGH SUNDAY. WHILE
THIS SOLUTION WOULD FAVOR A MAINLY DRY WEEKEND, THE UPPER LOW WILL
STILL BE CLOSE ENOUGH TO PRODUCE SCATTERED SHOWERS EACH AFTERNOON.
GIVEN THESE DISCREPANCIES, HAVE GONE WITH A CHANCE OF SHOWERS
EACH DAY OF THE LONG TERM PERIOD.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
NEAR TERM: EXPECT IFR CONDITIONS TONIGHT INTO MONDAY.
SHORT TO LONG TERM: GENERALLY VFR ALL TAF SITES XCPT MVFR/IFR IN
LATE NGT PATCHY FOG LATE TUE NGT AND IN TSTMS AND HEAVIER SHWRS
MSLY WED INTO WED NGT. PREVAILING VFR THEREAFTER WITH MVFR
POSSIBLE IN SCATTERED SHOWERS POSSIBLE EACH DAY THROUGH THE
WEEKEND.
&&
.MARINE...
NEAR TERM: HAVE USED A BLEND OF THE NAM12 AND GFS40 TO INITIALIZE
THE WIND GRIDS WILL LOWER MODEL WINDS SPEEDS ABOUT 50 PERCENT TO
BETTER FIT BUOY OBSERVATIONS. LATE THIS EVENING INTO MONDAY WILL
LOWER MODEL BLEND WINDS BY 20 PERCENT TO ADJUST FOR STRONG MARINE
LAYER. FOR WAVES: PRIMARY WAVE GROUP IS AROUND 4 FEET FROM 195
DEGREES AT 8 SECONDS AND ORIGINATES FROM FETCH AREA SOUTH AND
EAST OF GULF OF MAINE. SECONDARY LONG PERIOD GROUP AT 1 FOOT FROM
145 DEGREES AND 10 SECONDS. EXPECT COMBINED SEA TO STAY BELOW 5
FEET SO WILL NOT ISSUE SCA FOR SEAS BUT MAY COME CLOSE TO 5 FEET
FOR A FEW HOURS THIS EVENING. WILL USE NAM/SWAN FOR WAVES. STILL
DENSE FOG ACROSS COASTAL WATERS SO WILL KEEP AREAS OF FOG WITH
VISIBILITY BELOW 1 MILE THROUGH MONDAY MORNING THEN TRANSITION TO
PATCHY FOG IN AFTERNOON.
SHORT TERM: NO HDLNS ANTICIPATED THRU THE SHORT TERM. STABLE
SFC-500M AGL LAPSE RATES WILL PRECLUDE MUCH IN THE WAY OF MIXING
AND WIND SPEEDS ABV 12 KT. TDYS 12Z WW3 WV GUIDANCE WAS NOT TO
HIGH OVR OUTER WATERS...SO WE ONLY LOWERED IT BY 10-15 PERCENT OVR
OPEN WATERS AND LOWERED IT TO 1 TO 2 FT NEAR THE COASTLINE AND
INNER BAYS/HARBORS. WITH LITTLE IN THE WAY OF OFFSHORE WINDS MON
NGT TO BRING DRIER AIR OVR THE WATERS...WE KEPT A MENTION OF
PATCHY FOG OVR OUR MZS DURG THIS PD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...FITZSIMMONS/HEWITT/MIGNONE
SHORT TERM...VJN
LONG TERM...HASTINGS
AVIATION...FITZSIMMONS/HEWITT/MIGNONE
MARINE...FITZSIMMONS/HEWITT/MIGNONE/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
514 PM EDT SUN AUG 12 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OF THE REGION OVERNIGHT. A WEAK RIDGE
OF HIGH PRESSURE WILL MOVE ACROSS THE AREA MONDAY INTO TUESDAY THEN
ANOTHER LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH
ON WEDNESDAY FROM CENTRAL CANADA.
&&
.NEAR TERM /THROUGH MONDAY/...
UPDATE...ADDED THUNDER INTO THE FCST FOR THE NORTHERN AND CENTRAL
AREAS BASED ON LATEST RADAR, LTG DETECTION AND LAPS SOUNDINGS
SHOWING INSTABILITY HOLDING ON THROUGH 23Z AT LEAST. HIGH WBZS >
11.5K FT AND DUAL POL ASSESSMENT INDICATES HEAVY RAINFALL
POTENTIAL W/TSTMS.
PREVIOUS DISCUSSION...
LOW PRESSURE WILL MOVE INTO CENTRAL QUEBEC PROVINCE TONIGHT THEN
WEAKEN MONDAY. HAVE BASED POPS INTO THIS EVENING ON RUC13 THEN
TRANSITION TO THE A BLEND OF THE NAM12...GFS40...CMCREG AND ECMWF.
FOR TEMPERATURE AND DEW POINT HAVE USED THE GMOS. QPF BASED ON THE
A BLEND OF THE NAM12 AND GFS40. ATMOSPHERE LOOKS STABLE OVER
EASTERN MAINE SO WILL REMOVE MENTION OF THUNDER THIS EVENING AFTER
0000Z.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LGT WINDS WITH A WEAK SFC PRES GRAD AND AT LEAST PARTIALLY CLR
SKIES MON NGT ACROSS THE FA SHOULD ALLOW FOR ENOUGH RADIATIONAL
COOLING TO RESULT IN PATCHY VALLEY FOG LATE IN THE PD.
MOST IF NOT ALL OF THIS FOG SHOULD BURN OFF SHORTLY AFT SUNRISE
TUE ALLOWING FOR INTERVALS OF CLDS AND SUNSHINE ACROSS THE FA ALG
WITH WARM AFTN HI TEMPS MSLY IN THE LOWER TO MID 80S...XCPT COOLER
ALG THE IMMEDIATE COAST. THE STRENGTH OF THE S/WV RIDGE ALF SHOULD
MSLY PREVENT TSTM DEVELOPMENT...SO WE LOWERED POPS TO THE SLGT CHC
CAT MAINLY ACROSS NRN/WRN PTNS OF THE FA FOR THE AFTN AND EVE HRS.
MEANWHILE...A STRONGER S/WV MOVG E FROM CNTRL CAN WILL BEGIN TO
BRING HI/MID CLDS TO THE FA AS ERLY AS LATE TUE NGT. DUE TO THE
SLIGHTLY FASTER ARRIVAL OF THE S/WV THAN SHOWN IN MODELS YSTDY
ATTM...WE HELD OFF ON ANY FOG MENTION IN OUR FA LATE TUE NGT FOR
NOW. OTHERWISE...SHWRS COULD ARRIVE INTO WRN PTNS OF THE FA WED
MORN AND INTENSIFY TO TSTMS OVR CNTRL AND ERN PTNS OF THE FA WED
AFTN WITH MAX POTENTIAL AFTN SB CAPES OF 1000-1500 J/KG BASED ON
SREF PROJECTIONS WITH OPNL GFS/NAM PROJECTIONS UPWARDS OF 1500-
2000 J/KG LIKELY TO HI GIVEN CURRENT PROJECTIONS OF LMTD SUNSHINE
ON WED. FOR THIS REASON...WE WILL NOT BE INCLUDING ANY ENHANCED
TSTM WORDING IN OUR GRIDS FOR WED AFTN ATTM. HOWEVER...CONSENSUS
OF DIFFERENT MODEL 6 HRLY QPF PROJECTIONS FAVORED GOING UP TO LOW
CAT POPS SPCLY W...N AND CNTRL PTNS OF THE FA WED AFTN WITH LIKELY
POPS OVR DOWNEAST AREAS AND CHC POPS OVR THE WATERS.
AFT MILD OVRNGT LOWS TUE NGT...HI TEMPS WED WILL LIKELY BE HELD
BACK BY CLD CVR...SPCLY OVR NRN AND WRN PTNS OF THE REGION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UNSETTLED CONDITIONS WILL CONTINUE THROUGH THE END OF THE WEEK INTO
THE WEEKEND AS THE REGION REMAINS UNDER THE INFLUENCE OF AN UPPER
TROUGH. RIGHT OFF THE BAT, THE FORECAST MODELS ARE HAVING TROUBLE
AGREEING ON THE HANDLING OF THIS TROUGH AND THE SHORTWAVES THAT WILL
TRAVERSE AROUND ITS PERIPHERY. WHILE THE GFS AND ECMWF BOTH HAVE A
CLOSED SHORTWAVE IN THE VICINITY OF SOUTHERN WEDNESDAY EVENING, THE
GFS OPENS THE WAVE UP WEDNESDAY NIGHT AND SHUNTS IT EASTWARD
THURSDAY. THIS ALLOWS A BRIEF RIDGE TO BUILD OVER NEW ENGLAND
THURSDAY INTO EARLY FRIDAY, MEANING DRY WEATHER FOR THAT TIME
PERIOD. THE GFS THEN PRODUCES SEVERAL ROUNDS OF SHOWERS OVER THE
STATE THROUGH THE WEEKEND AS WAVES MOVE THROUGH THE SOUTHWEST FLOW
ALOFT AHEAD OF THE MAIN UPPER LOW. MEANWHILE, THE ECMWF CUTS OFF THE
FIRST UPPER SHORTWAVE WEDNESDAY NIGHT AND THEN SLOWLY MOVES IT EAST
TO NOVA SCOTIA BY SATURDAY MORNING. ONLY THEN DOES IT SHOW SOME
RIDGING AT THE SURFACE AND ALOFT, FRIDAY NIGHT THROUGH SUNDAY. WHILE
THIS SOLUTION WOULD FAVOR A MAINLY DRY WEEKEND, THE UPPER LOW WILL
STILL BE CLOSE ENOUGH TO PRODUCE SCATTERED SHOWERS EACH AFTERNOON.
GIVEN THESE DISCREPANCIES, HAVE GONE WITH A CHANCE OF SHOWERS
EACH DAY OF THE LONG TERM PERIOD.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: EXPECT IFR CONDITIONS TONIGHT INTO MONDAY.
SHORT TO LONG TERM: GENERALLY VFR ALL TAF SITES XCPT MVFR/IFR IN
LATE NGT PATCHY FOG LATE TUE NGT AND IN TSTMS AND HEAVIER SHWRS
MSLY WED INTO WED NGT. PREVAILING VFR THEREAFTER WITH MVFR
POSSIBLE IN SCATTERED SHOWERS POSSIBLE EACH DAY THROUGH THE
WEEKEND.
&&
.MARINE...
NEAR TERM: HAVE USED A BLEND OF THE NAM12 AND GFS40 TO INITIALIZE
THE WIND GRIDS WILL LOWER MODEL WINDS SPEEDS ABOUT 50 PERCENT TO
BETTER FIT BUOY OBSERVATIONS. LATE THIS EVENING INTO MONDAY WILL
LOWER MODEL BLEND WINDS BY 20 PERCENT TO ADJUST FOR STRONG MARINE
LAYER. FOR WAVES: PRIMARY WAVE GROUP IS AROUND 4 FEET FROM 195
DEGREES AT 8 SECONDS AND ORIGINATES FROM FETCH AREA SOUTH AND
EAST OF GULF OF MAINE. SECONDARY LONG PERIOD GROUP AT 1 FOOT FROM
145 DEGREES AND 10 SECONDS. EXPECT COMBINED SEA TO STAY BELOW 5
FEET SO WILL NOT ISSUE SCA FOR SEAS BUT MAY COME CLOSE TO 5 FEET
FOR A FEW HOURS THIS EVENING. WILL USE NAM/SWAN FOR WAVES. STILL
DENSE FOG ACROSS COASTAL WATERS SO WILL KEEP AREAS OF FOG WITH
VISIBILITY BELOW 1 MILE THROUGH MONDAY MORNING THEN TRANSITION TO
PATCHY FOG IN AFTERNOON.
SHORT TERM: NO HDLNS ANTICIPATED THRU THE SHORT TERM. STABLE
SFC-500M AGL LAPSE RATES WILL PRECLUDE MUCH IN THE WAY OF MIXING
AND WIND SPEEDS ABV 12 KT. TDYS 12Z WW3 WV GUIDANCE WAS NOT TO
HIGH OVR OUTER WATERS...SO WE ONLY LOWERED IT BY 10-15 PERCENT OVR
OPEN WATERS AND LOWERED IT TO 1 TO 2 FT NEAR THE COASTLINE AND
INNER BAYS/HARBORS. WITH LITTLE IN THE WAY OF OFFSHORE WINDS MON
NGT TO BRING DRIER AIR OVR THE WATERS...WE KEPT A MENTION OF
PATCHY FOG OVR OUR MZS DURG THIS PD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/MIGNONE
SHORT TERM...VJN
LONG TERM...HASTINGS
AVIATION...HEWITT/MIGNONE
MARINE...HEWITT/MIGNONE/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
321 PM EDT SUN AUG 12 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OF THE REGION OVERNIGHT. A WEAK RIDGE
OF HIGH PRESSURE WILL MOVE ACROSS THE AREA MONDAY INTO TUESDAY THEN
ANOTHER LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH
ON WEDNESDAY FROM CENTRAL CANADA.
&&
.NEAR TERM /THROUGH MONDAY/...
LOW PRESSURE WILL MOVE INTO CENTRAL QUEBEC PROVINCE TONIGHT THEN
WEAKEN MONDAY. HAVE BASED POPS INTO THIS EVENING ON RUC13 THEN
TRANSITION TO THE A BLEND OF THE NAM12...GFS40...CMCREG AND ECMWF.
FOR TEMPERATURE AND DEW POINT HAVE USED THE GMOS. QPF BASED ON THE
A BLEND OF THE NAM12 AND GFS40. ATMOSPHERE LOOKS STABLE OVER
EASTERN MAINE SO WILL REMOVE MENTION OF THUNDER THIS EVENING AFTER
0000Z.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LGT WINDS WITH A WEAK SFC PRES GRAD AND AT LEAST PARTIALLY CLR
SKIES MON NGT ACROSS THE FA SHOULD ALLOW FOR ENOUGH RADIATIONAL
COOLING TO RESULT IN PATCHY VALLEY FOG LATE IN THE PD.
MOST IF NOT ALL OF THIS FOG SHOULD BURN OFF SHORTLY AFT SUNRISE
TUE ALLOWING FOR INTERVALS OF CLDS AND SUNSHINE ACROSS THE FA ALG
WITH WARM AFTN HI TEMPS MSLY IN THE LOWER TO MID 80S...XCPT COOLER
ALG THE IMMEDIATE COAST. THE STRENGTH OF THE S/WV RIDGE ALF SHOULD
MSLY PREVENT TSTM DEVELOPMENT...SO WE LOWERED POPS TO THE SLGT CHC
CAT MAINLY ACROSS NRN/WRN PTNS OF THE FA FOR THE AFTN AND EVE HRS.
MEANWHILE...A STRONGER S/WV MOVG E FROM CNTRL CAN WILL BEGIN TO
BRING HI/MID CLDS TO THE FA AS ERLY AS LATE TUE NGT. DUE TO THE
SLIGHTLY FASTER ARRIVAL OF THE S/WV THAN SHOWN IN MODELS YSTDY
ATTM...WE HELD OFF ON ANY FOG MENTION IN OUR FA LATE TUE NGT FOR
NOW. OTHERWISE...SHWRS COULD ARRIVE INTO WRN PTNS OF THE FA WED
MORN AND INTENSIFY TO TSTMS OVR CNTRL AND ERN PTNS OF THE FA WED
AFTN WITH MAX POTENTIAL AFTN SB CAPES OF 1000-1500 J/KG BASED ON
SREF PROJECTIONS WITH OPNL GFS/NAM PROJECTIONS UPWARDS OF 1500-
2000 J/KG LIKELY TO HI GIVEN CURRENT PROJECTIONS OF LMTD SUNSHINE
ON WED. FOR THIS REASON...WE WILL NOT BE INCLUDING ANY ENHANCED
TSTM WORDING IN OUR GRIDS FOR WED AFTN ATTM. HOWEVER...CONSENSUS
OF DIFFERENT MODEL 6 HRLY QPF PROJECTIONS FAVORED GOING UP TO LOW
CAT POPS SPCLY W...N AND CNTRL PTNS OF THE FA WED AFTN WITH LIKELY
POPS OVR DOWNEAST AREAS AND CHC POPS OVR THE WATERS.
AFT MILD OVRNGT LOWS TUE NGT...HI TEMPS WED WILL LIKELY BE HELD
BACK BY CLD CVR...SPCLY OVR NRN AND WRN PTNS OF THE REGION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UNSETTLED CONDITIONS WILL CONTINUE THROUGH THE END OF THE WEEK INTO
THE WEEKEND AS THE REGION REMAINS UNDER THE INFLUENCE OF AN UPPER
TROUGH. RIGHT OFF THE BAT, THE FORECAST MODELS ARE HAVING TROUBLE
AGREEING ON THE HANDLING OF THIS TROUGH AND THE SHORTWAVES THAT WILL
TRAVERSE AROUND ITS PERIPHERY. WHILE THE GFS AND ECMWF BOTH HAVE A
CLOSED SHORTWAVE IN THE VICINITY OF SOUTHERN WEDNESDAY EVENING, THE
GFS OPENS THE WAVE UP WEDNESDAY NIGHT AND SHUNTS IT EASTWARD
THURSDAY. THIS ALLOWS A BRIEF RIDGE TO BUILD OVER NEW ENGLAND
THURSDAY INTO EARLY FRIDAY, MEANING DRY WEATHER FOR THAT TIME
PERIOD. THE GFS THEN PRODUCES SEVERAL ROUNDS OF SHOWERS OVER THE
STATE THROUGH THE WEEKEND AS WAVES MOVE THROUGH THE SOUTHWEST FLOW
ALOFT AHEAD OF THE MAIN UPPER LOW. MEANWHILE, THE ECMWF CUTS OFF THE
FIRST UPPER SHORTWAVE WEDNESDAY NIGHT AND THEN SLOWLY MOVES IT EAST
TO NOVA SCOTIA BY SATURDAY MORNING. ONLY THEN DOES IT SHOW SOME
RIDGING AT THE SURFACE AND ALOFT, FRIDAY NIGHT THROUGH SUNDAY. WHILE
THIS SOLUTION WOULD FAVOR A MAINLY DRY WEEKEND, THE UPPER LOW WILL
STILL BE CLOSE ENOUGH TO PRODUCE SCATTERED SHOWERS EACH AFTERNOON.
GIVEN THESE DISCREPANCIES, HAVE GONE WITH A CHANCE OF SHOWERS
EACH DAY OF THE LONG TERM PERIOD.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: EXPECT IFR CONDITIONS TONIGHT INTO MONDAY.
SHORT TO LONG TERM: GENERALLY VFR ALL TAF SITES XCPT MVFR/IFR IN
LATE NGT PATCHY FOG LATE TUE NGT AND IN TSTMS AND HEAVIER SHWRS
MSLY WED INTO WED NGT. PREVAILING VFR THEREAFTER WITH MVFR
POSSIBLE IN SCATTERED SHOWERS POSSIBLE EACH DAY THROUGH THE
WEEKEND.
&&
.MARINE...
NEAR TERM: HAVE USED A BLEND OF THE NAM12 AND GFS40 TO INITIALIZE
THE WIND GRIDS WILL LOWER MODEL WINDS SPEEDS ABOUT 50 PERCENT TO
BETTER FIT BUOY OBSERVATIONS. LATE THIS EVENING INTO MONDAY WILL
LOWER MODEL BLEND WINDS BY 20 PERCENT TO ADJUST FOR STRONG MARINE
LAYER. FOR WAVES: PRIMARY WAVE GROUP IS AROUND 4 FEET FROM 195
DEGREES AT 8 SECONDS AND ORIGINATES FROM FETCH AREA SOUTH AND
EAST OF GULF OF MAINE. SECONDARY LONG PERIOD GROUP AT 1 FOOT FROM
145 DEGREES AND 10 SECONDS. EXPECT COMBINED SEA TO STAY BELOW 5
FEET SO WILL NOT ISSUE SCA FOR SEAS BUT MAY COME CLOSE TO 5 FEET
FOR A FEW HOURS THIS EVENING. WILL USE NAM/SWAN FOR WAVES. STILL
DENSE FOG ACROSS COASTAL WATERS SO WILL KEEP AREAS OF FOG WITH
VISIBILITY BELOW 1 MILE THROUGH MONDAY MORNING THEN TRANSITION TO
PATCHY FOG IN AFTERNOON.
SHORT TERM: NO HDLNS ANTICIPATED THRU THE SHORT TERM. STABLE
SFC-500M AGL LAPSE RATES WILL PRECLUDE MUCH IN THE WAY OF MIXING
AND WIND SPEEDS ABV 12 KT. TDYS 12Z WW3 WV GUIDANCE WAS NOT TO
HIGH OVR OUTER WATERS...SO WE ONLY LOWERED IT BY 10-15 PERCENT OVR
OPEN WATERS AND LOWERED IT TO 1 TO 2 FT NEAR THE COASTLINE AND
INNER BAYS/HARBORS. WITH LITTLE IN THE WAY OF OFFSHORE WINDS MON
NGT TO BRING DRIER AIR OVR THE WATERS...WE KEPT A MENTION OF
PATCHY FOG OVR OUR MZS DURG THIS PD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...VJN
LONG TERM...HASTINGS
AVIATION...MIGNONE
MARINE...MIGNONE/VJN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
327 AM EDT SUN AUG 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY DECREASE CLOUDS TODAY AND PROVIDE
COMFORTABLE CONDITIONS INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN TROUGH AXIS, ON THE SOUTHERN FLANK OF THE EXITING UPPER
LEVEL LOW, WILL MOVE THROUGH OHIO VALLEY THIS MORNING. THE LAST
UL WAVE WILL SWING THROUGH WITH THE AXIS, PROVIDING CLOUDS AND
POSSIBLY KICKING OFF A SHOWER IN THE NORTH. ONCE THE AXIS SWINGS
THROUGH, CLOUDS WILL BEGIN TO RETREAT TO THE NORTHEAST, ALLOWING
FOR AN INCREASE IN SUNSHINE FROM THE SOUTHWEST LATE THIS MORNING.
THE RETURN OF SUNSHINE, WILL PROVIDE MODERATING TEMPS. THE NORTH
WILL BE LAST TO SEE THE SUN AND WILL CONTINUE TO SEE COOL AND
CLOUDY CONDITIONS THROUGH MOST OF THE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SFC HIGH WILL MOVE INTO THE MID-ATLANTIC BY MONDAY MORNING. MONDAY
WILL BE A DAY OF INCREASING CLOUD COVER AHEAD OF THE NEXT
DEVELOPING SYSTEM. HIGH CLOUDS WILL MOVE IN EARLY MONDAY MORNING,
WITH MID CLOUDS COVERING MUCH OF THE REGION DURING THE AFTERNOON.
THE NEXT SFC LOW WILL MOVE ACROSS THE MIDWEST MONDAY, AHEAD OF A
DIGGING UL TROUGH. THE SFC LOW, AND ITS COLD FRONT, WILL MOVE INTO W
OHIO MONDAY NIGHT WITH THE TROUGH TRAILING CLOSE BEHIND. WOULD
EXPECT SHOWERS TO MOVE INTO THE WEST LATE MONDAY NIGHT AND
PROGRESS EASTWARD INTO TUESDAY. ATMOSPHERE IS SOMEWHAT UNSTABLE
TUESDAY AND THERE WILL BE A PUSH OF HIGHER TDS AHEAD OF THE SFC
FRONT. WILL INCLUDE THE MENTION OF STORMS ON TUESDAY, WITH THE
BEST CHANCE COMING WITH THE PASSAGE OF THE SFC FRONT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A SECONDARY SFC FRONT WILL SWING THROUGH WITH THE TROUGH AXIS
TUESDAY NIGHT. WILL NEED TO LEAVE IN THE CHANCE FOR A SHOWER OR
STORM TUESDAY EVENING WITH THE CROSSING BOUNDARY.
STILL SOME TIMING AND STRENGTH DISCREPANCIES IN THE MEDIUM RANGE
MODELS. HAVE MADE VERY LITTLE CHANGES TO LONG TERM FORECAST.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
RECENT SATELLITE AND SURFACE DATA SHOW BROKEN COLD-POOL
STRATOCUMULUS, WITH MOST CEILINGS IN THE VFR RANGE, CONTINUING
ACROSS THE UPPER OHIO VALLEY OVERNIGHT. GFS LAMP AND NAM MOS SUGGEST
NOCTURNAL COOLING MAY INDUCE IFR CEILINGS AND MVFR VISIBILITIES IN
FOG PRIOR TO SUNRISE AT 11Z. ON THE OTHER HAND, HRRR MODEL OUTPUT
SHOWED A SLOW DECREASE IN CLOUD COVERAGE, WITH GENERALLY NO MORE
THAN SCATTERED COVERAGE BY MIDDAY.
FOR NOW HAVE HEDGED WITH A TEMPORARY DETERIORATION TO MVFR
RESTRICTIONS PRIOR TO SUNRISE /11Z/, THEN OPTED FOR VFR
STRATOCUMULUS CEILINGS TO BECOME SCATTERED SOUTH OF THE I-80
CORRIDOR BY AFTERNOON /16Z/ AND ACROSS THE NORTH BEFORE EVENING
/00Z/. VFR TO THEN CONTINUE TONIGHT.
SURFACE WINDS WILL BE FROM THE SOUTHWEST NEAR 5 KTS THIS MORNING,
THEN BECOME MORE WESTERLY NEAR 10 KTS THIS AFTERNOON, BEFORE
BECOMING LIGHT TONIGHT.
.OUTLOOK...MONDAY THROUGH THURSDAY...
NEXT POSSIBLE RESTRICTIONS WILL BE DUE TO SCATTERED SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PASSAGE OF LOW PRESSURE TUESDAY
INTO EARLY WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
104 AM EDT SUN AUG 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY DECREASE CLOUDS TODAY AND PROVIDE
COMFORTABLE CONDITIONS INTO MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
50H LOW CONTINUES TO SPIN INTO CANADA. THE MAIN TROUGH AXIS ON THE
SOUTHERN FLANK OF THE LOW WILL MOVE THROUGH THE UPPER OHIO VALLEY
THIS MORNING. THE LAST UL WAVE WILL SWING THROUGH WITH THE AXIS,
KEEPING IN THE CLOUDS AND POSSIBLY KICKING OFF A SHOWER IN THE
NORTH. ONCE THE AXIS SWINGS THROUGH, CLOUDS WILL BEGIN TO RETREAT
TO THE NORTHEAST, ALLOWING FOR AN INCREASE IN SUNSHINE FROM THE
SOUTHWEST LATE THIS MORNING. THE RETURN OF SUNSHINE, WILL PROVIDE
MODERATING TEMPS. THE NORTH WILL BE LAST TO SEE THE SUN AND WILL
CONTINUE TO SEE COOL AND CLOUDY CONDITIONS THROUGH MOST OF THE
DAY.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
SFC HIGH WILL MOVE INTO THE MID-ATLANTIC BY MONDAY MORNING. MONDAY
WILL BE A DAY OF INCREASING CLOUD COVER AHEAD OF THE NEXT
DEVELOPING SYSTEM. HIGH CLOUDS WILL MOVE IN EARLY MONDAY MORNING,
WITH MID CLOUDS COVERING MUCH OF THE REGION DURING THE AFTERNOON.
THE NEXT SFC LOW WILL MOVE ACROSS THE MIDWEST MONDAY, AHEAD OF A
DIGGING UL TROUGH. THE SFC LOW, AND ITS COLD FRONT, WILL MOVE INTO W
OHIO MONDAY NIGHT WITH THE TROUGH TRAILING CLOSE BEHIND. WOULD
EXPECT SHOWERS TO MOVE INTO THE WEST LATE MONDAY NIGHT AND
PROGRESS EASTWARD INTO TUESDAY. ATMOSPHERE IS SOMEWHAT UNSTABLE
TUESDAY AND THERE WILL BE A PUSH OF HIGHER TDS AHEAD OF THE SFC
FRONT. WILL INCLUDE THE MENTION OF STORMS ON TUESDAY, WITH THE
BEST CHANCE COMING WITH THE PASSAGE OF THE SFC FRONT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A SECONDARY SFC FRONT WILL SWING THROUGH WITH THE TROUGH AXIS
TUESDAY NIGHT. WILL NEED TO LEAVE IN THE CHANCE FOR A SHOWER OR
STORM TUESDAY EVENING WITH THE CROSSING BOUNDARY.
STILL SOME TIMING AND STRENGTH DISCREPANCIES IN THE MEDIUM RANGE
MODELS. HAVE MADE VERY LITTLE CHANGES TO LONG TERM FORECAST.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
RECENT SATELLITE AND SURFACE DATA SHOW BROKEN COLD-POOL
STRATOCUMULUS, WITH MOST CEILINGS IN THE VFR RANGE, CONTINUING
ACROSS THE UPPER OHIO VALLEY OVERNIGHT. GFS LAMP AND NAM MOS SUGGEST
NOCTURNAL COOLING MAY INDUCE IFR CEILINGS AND MVFR VISIBILITIES IN
FOG PRIOR TO SUNRISE AT 11Z. ON THE OTHER HAND, HRRR MODEL OUTPUT
SHOWED A SLOW DECREASE IN CLOUD COVERAGE, WITH GENERALLY NO MORE
THAN SCATTERED COVERAGE BY MIDDAY.
FOR NOW HAVE HEDGED WITH A TEMPORARY DETERIORATION TO MVFR
RESTRICTIONS PRIOR TO SUNRISE /11Z/, THEN OPTED FOR VFR
STRATOCUMULUS CEILINGS TO BECOME SCATTERED SOUTH OF THE I-80
CORRIDOR BY AFTERNOON /16Z/ AND ACROSS THE NORTH BEFORE EVENING
/00Z/. VFR TO THEN CONTINUE TONIGHT.
SURFACE WINDS WILL BE FROM THE SOUTHWEST NEAR 5 KTS THIS MORNING,
THEN BECOME MORE WESTERLY NEAR 10 KTS THIS AFTERNOON, BEFORE
BECOMING LIGHT TONIGHT.
.OUTLOOK...MONDAY THROUGH THURSDAY...
NEXT POSSIBLE RESTRICTIONS WILL BE DUE TO SCATTERED SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PASSAGE OF LOW PRESSURE TUESDAY
INTO EARLY WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
756 PM EDT MON AUG 13 2012
.SYNOPSIS...
ISSUED AT 311 PM EDT MON AUG 13 2012
RAIN SHOWERS WILL CONTINUE INTO TONIGHT AS LOW PRESSURE MOVES
SOUTH OF LOWER MICHIGAN. FAIR WEATHER WILL FOLLOW FOR TUESDAY AND
WEDNESDAY BUT STRONG THUNDERSTORMS ARE POSSIBLE THURSDAY NIGHT AS
A COLD FRONT MOVES THROUGH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 311 PM EDT MON AUG 13 2012
LOWERED POPS A BIT TONIGHT AND TUESDAY MORNING. DROPPED POPS FOR
TUESDAY AFTERNOON AND WEDNESDAY NIGHT.
RADAR TRENDS AND HRRR INDICATE THAT MOST OF THE SHOWERS WILL BE
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA WITH MORE SCATTERED
RAIN SHOWERS ACROSS THE NORTH. ADJUSTED POPS TO REFLECT THIS AND
ADDED AREAS OF FOG AFTER MIDNIGHT GIVEN THE EXPECTED LIGHT WINDS
AND HIGH LOW LEVEL RH. LEFT THUNDER OUT OF THE FORECAST DUE TO
MARGINAL INSTABILITY BUT CANNOT RULE OUT AN ISOLATED THUNDERSTORM.
NAM AND GFS CROSS SECTIONS SHOW A QUICKER DEPARTURE OF THE DEEPER
RH ON TUESDAY...SO TRIMMED POPS FOR THE MORNING AND DROPPED THEM
FOR THE AFTERNOON FOR ALL ZONES.
WEAK SFC RIDGING MOVES IN FOR TUESDAY NIGHT AND WEDNESDAY BUT
UPPER TROUGH AMPLIFICATION WILL LEAD TO STRONG SFC COLD FRONT
MOVING TOWARDS LOWER MICHIGAN WEDNESDAY NIGHT. AT HIS POINT IT
APPEARS THE ST ROMS ALONG THE FRONT WILL HOLD OFF UNTIL LATER
THURSDAY...SO DROPPED POPS FOR WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 311 PM EDT MON AUG 13 2012
MAIN FOCUS OF THE FCST CONTINUES TO BE THE STRONG FRONT EXPECTED TO
MOVE THROUGH THU/THU NIGHT. THE WEEKEND LOOKS COOL AND POTENTIALLY A
LITTLE UNSETTLED WITH TROUGHING HANGING OUT OVER THE REGION. NO REAL
CHANGES WERE MADE TO THE FCST.
PCPN CHANCES WILL BE GRADUALLY INCREASING AT THE BEGINNING OF THE
LONG TERM PERIOD ON THU. THIS OCCURS AS UPPER RIDGING MOVES EAST OF
THE AREA...AND THE STRONG UPPER SYSTEM CURRENTLY MOVING INTO NW
BRITISH COLUMBIA DIGS INTO THE REGION. MODELS CONTINUE TO INDICATE
THAT MOST OF THE PCPN WITH THE SFC FRONT WILL BE RIGHT ALONG AND
JUST BEHIND THE FRONT. THIS IS WHERE THE TAIL END OF THE UPPER
TROUGH AND SFC FRONT OVERLAP.
IT CONTINUES TO LOOK LIKE CLOUDS OUT AHEAD OF THE FRONT WILL
SUPPRESS DIURNAL INSTABILITY SOME. MODELS INDICATE THAT AT LEAST A
FEW HUNDRED J/KG OF ML CAPE WILL BE LIKELY...AND THE GFS /LIKELY
OVERDONE DUE TO SFC DEW POINTS/ SHOWS MORE POTENTIAL INSTABILITY.
DEEP LAYER SHEAR STILL LOOKS TO BE MARGINAL ALONG THE FRONT...WITH
MUCH BETTER VALUES POST-FRONTAL. WE STILL EXPECT THAT STRONG STORMS
WILL BE POSSIBLE DUE TO THE STRENGTH OF THE FRONT AND UPPER TROUGH
THAT COULD COMPENSATE FOR MARGINAL SHEAR AND INSTABILITY.
ONCE THE UPPER TROUGH SUPPORTING THE FRONT MOVES IN...IT LOOKS TO
BECOME ESTABLISHED OVER THE AREA THROUGH THE REMAINDER OF THE
PERIOD. WE WILL SEE SHORT WAVE ENERGY CONTINUE TO DIVE INTO THE MEAN
TROUGH OVER THE GREAT LAKES...HELPING TO REINFORCE IT. THIS WILL
KEEP A CHC OF MAINLY DIURNAL SHOWERS AROUND THROUGH NEXT MON. THE
AREA WILL SEE FALL-LIKE TEMPS IN THE 60S AND TO AROUND 70 FOR THE
WEEKEND. TEMPS WILL SLOWLY MODIFY INTO THE 70S BY MON NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 756 PM EDT MON AUG 13 2012
A FEW POCKETS OF MVFR CONDITIONS CAN BE EXPECTED THIS EVENING AS
SCATTERED RAIN SHOWERS MOVE THROUGH. HOWEVER AFTER MIDNIGHT LOOK
FOR IFR/LIFR CONDITIONS TO DEVELOP AS LOW STRATUS AND FOG FORMS.
CONFIDENCE IN THIS SCENERIO IS INCREASING...AND THE MORNING RUSH
TIME COULD BE NEGATIVELY IMPACTED BY THE LOW CIGS/VSBYS.
IFR/LIFR CONDITIONS SHOULD LIFT BY MID MORNING TUESDAY WITH VFR
FOLLOWING. A FEW ISOLD/SCT TSTMS COULD DEVELOP TUESDAY
AFTERNOON... BUT DID NOT PUT MENTION OF TS/CB IN THE TAFS SINCE
CONFIDENCE IS CURRENTLY TOO LOW.
&&
.MARINE...
ISSUED AT 311 PM EDT MON AUG 13 2012
SOME FOG IS POSSIBLE ALONG THE COAST WHERE COOLER WATERS HAVE BEEN
STIRRED UP BY LAST WEEKS STORM. OTHERWISE...NO SIGNIFICANT WEATHER
IS EXPECTED UNTIL THURSDAY OR THURSDAY NIGHT WHEN A COLD FRONT
BRINGS THE CHANCE FOR STRONG THUNDERSTORMS.
&&
.HYDROLOGY...
ISSUED AT 311 PM EDT MON AUG 13 2012
RAINS TODAY AND TONIGHT SHOULD NOT AFFECT RIVER LEVELS. SOME
HEAVIER RAINS ARE POSSIBLE THURSDAY AND THURSDAY NIGHT WITH A HALF
TO AN INCH OF BASIN AVERAGE QPF POSSIBLE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...MEADE
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
735 PM EDT MON AUG 13 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 407 PM EDT MON AUG 13 2012
WV LOOP AND RAOBS INDICATE UPPER TROUGHS FROM NORTHERN ONTARIO
THROUGH THE WESTERN GREAT LAKES REGION. STRONGEST SHORTWAVES IN
THE MEAN TROUGH ARE OVER NORTHERN ONTARIO AND ALSO SOUTHERN LOWER
MICHIGAN. SHORTWAVE BTWN THE TWO TROUGHS AND SFC TROUGH MERGED UP
WITH LAKE BREEZES OVR CNTRL UPR MICHIGAN EARLIER THIS AFTN TO KICK
OFF ISOLD SHRA AND STORMS. CONVECTIVE DEPTH WAS SHALLOW...BUT RADAR
ESTIMATED PRECIP AMOUNTS UP TO 1-1.5 INCHES SEEMED REASONABLE AS
STORM MOTION WAS SLOW AND EVEN TRIED TO BACKBUILD OVR EXTREME
SOUTH CENTRAL MARQUETTE COUNTY AS ONE STORM BRIEFLY BECAME A RIGHT
MOVER.
AS OF 19Z...THE MESS OF THE SYNOPTIC TROUGH AND LAKE BREEZE
CONVERGENCE BOUNDARY IS ORIENTED FM ROUGHLY WATERSMEET THROUGH JUST
NORTH OF CRYSTAL FALLS AND IRON MOUNTAIN AND EAST TOWARD NEWBERRY
AND SAULT STE MARIE. ISOLD-SCATTERED SHRA/TSRA ARE LOCATED ALONG THE
TROUGH WITH STORM MOTIONS GENERALLY ESE AROUND 15 MPH. BASED ON
RADAR TRENDS AND HRRR MODEL...HIGHLIGHTED HIGHEST POPS EARLY THIS
EVENING OVR SCNTRL UPR MICHIGAN...WITH DIMINISHING TREND BY LATE
EVENING DUE TO LOSS OF DAYTIME INSTABILITY AND LOW-LEVEL
CONVERGENCE. STILL...AT LEAST ISOLD SHRA/TSRA MAY TRY TO STICK
AROUND THROUGH EVEN AFTER MIDNIGHT IN THE FAR SCNTRL WITH LINGERING
WEAKER SHORTWAVE ENERGY OVERHEAD AND STEEPER MID-LEVEL LAPSE RATES
AND H85-H7 MOISTURE. ALL CONVECTION SHOULD BE OUT OF CWA BY LATE
TONIGHT. TEMPS OVER INTERIOR WEST MAY TRY TO FALL OFF INTO THE 40S
LATE TONIGHT WITH A LOWER PWAT MIN LOCATED THERE. A BIT OF WIND AND
POSSIBLE SCT-BKN MID CLOUDS SHOULD KEEP REST OF CWA IN THE 50S.
ON TUESDAY...DAY STARTS OFF WITH THE SCT-BKN MID CLOUDS WITH CU
BUILDUP BY LATE MORNING AS CONVECTIVE TEMPS ARE IN THE LOWER 70S.
SHORTWAVE ON BACK SIDE OF LARGER SCALE TROUGH IN CNTRL SASKATCHEWAN
AND/OR MANITOBA FCST TO SLIDE INTO CNTRL CWA BY MID AFTN. GIVEN
SIMILAR FCST SBCAPES IN THE 700-1000J/KG RANGE COULD SEE REPEAT
PERFORMANCE OF TODAY...OR AT LEAST SOMEWHAT SIMILAR...WITH
ISOLD-SCATTERED SHRA/TSRA FORMING SHORTLY AFTER CONVECTIVE TEMPS
ARE REACHED. MAIN DIFFERENCE IS THE SHORTWAVE IS NOT AS STRONG AND
LOW-LEVEL CONVERGENCE WILL BE STRICTLY DRIVEN BY LAKE BREEZES FM
LAKE SUPERIOR/LAKE MICHIGAN. MSLP/WIND PATTERN POINTS TO AREA BTWN
SAW-IMT-ESC STAND TO SEE BEST COVERAGE OF SHRA/TSRA. FREEZING LEVELS
AROUND 11KFT AGL AND H85-H7 WINDS FAIRLY SIMILAR TO TODAY AS
WELL...SO AGAIN COULD SEE SLOW MOVING STORMS WITH MAIN HAZARDS
LIGHTNING AND HEAVY DOWNPOURS. SMALL HAIL COULD ALSO OCCUR WITH
STRONGEST STORMS. CONVERGENCE WANES BY LATE AFTN SO KEPT WITH IDEA
THAT POPS WILL BE OUT OF THE CWA BY EARLY TUESDAY EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 407 PM EDT MON AUG 13 2012
TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON...THE UPPER LEVEL TROUGH
WITH AXIS EXTENDING SOUTHWARD FROM CENTRAL ONTARIO THROUGH THE
EASTERN HALF OF UPPER MI AND INTO THE WESTERN HALF OF LOWER MI WILL
SHIFT EASTWARD OVERNIGHT...REACHING THE LOWER GREAT LAKES BY
WEDNESDAY AFTERNOON. AS THIS TROUGH SHIFTS EASTWARD A SURFACE AND
WEAK UPPER LEVEL RIDGE WILL BUILD INTO THE UPPER GREAT LAKES
REGION...BRIEFLY BRINGING AND END TO THE CHANCES OF PRECIPITATION.
WEDNESDAY EVENING THROUGH FRIDAY NIGHT...AS THE SURFACE RIDGE AND
UPPER LEVEL RIDGE BEGIN TO SHIFT EASTWARD TO THE LOWER GREAT LAKES
ATTENTION WILL THEN TURN TO AN APPROACHING LOW PRESSURE SYSTEM
CENTERED OVER NORTHERN MN...WITH ASSOCIATED UPPER LEVEL TROUGH TO
THE WEST OF THE SURFACE LOW...INDICATED BY BOTH THE
EC/GFS...SUGGESTING THAT THE SURFACE LOW IS EXPECTED TO INTENSIFY.
THE LOW WILL PASS TO THE NORTH OF THE UPPER PENINSULA BY 12Z
THURSDAY AS IT DRAGS A COLD FRONT THROUGH INTO CENTRAL UPPER MI
AROUND THE SAME TIME AS INDICATED BY PLOTTING MSLP/850 THETA
E/SURFACE WINDS. THE MAIN AREA OF PRECIPITATION WILL LIKELY BE
PEGGED TO THE FRONT OF THE COLD FRONT AS THE FORCING APPEARS THE
GREATEST ALONG THIS AREA AS SHOWN BY PLOTTING 500-300MB DIVQ ALONG
WITH 1000-500 RH VALUES. MU CAPE VALUES AREA PROGGED TO BE AROUND
500-800 J/KG OVER MUCH OF THE AREA OVER THE WESTERN HALF OF THE AREA
AROUND 06Z SHIFTING TO THE EAST HALF AROUND 12Z THURSDAY. 0-6 KM
SHEAR VALUES ARE EXPECTED TO BE AROUND 30 TO 35 KNOTS AHEAD OF THE
FRONT WITH VALUES INCREASING TO AROUND 50 KNOTS ALONG AND BEHIND THE
FRONT. SHEAR VALUES BEING MARGINAL FOR SEVERE WEATHER AHEAD OF THE
FRONT ALONG WITH CAPE IN THE HAIL GROWTH ZONE AROUND 100-200 J/KG
WOULD INDICATE ONLY A MARGINAL THREAT OF HAIL. DCAPE VALUES ARE
FAIRLY LOW WITH VALUES AROUND 100-150 J/KG DUE TO A LACK OF DRY AIR
IN THE MID LEVEL. THURSDAY NIGHT THROUGH FRIDAY NIGHT THE UPPER
LEVEL TROUGH WILL REMAIN OVER UPPER MI...WHILE SHIFTING EVER SO
SLOWLY TO THE EAST AS THE SURFACE LOW PULLS OT THE NORTHEAST TO
WESTERN QUEBEC. THE COOLER AIR WRAPPING AROUND THE BACK SIDE OF THE
LOW ALONG WITH DECREASED TEMPERATURES ALOFT...AROUND 4 TO 6C AT
H850...WILL HELP TO INCREASE THE CHANCE OF LAKE EFFECT SHOWERS OVER
THOSE AREAS FAVORED BY NORTH WINDS. HAVE ALSO INCREASED THE WINDS
OVER THE CENTRAL AND EASTERN PORTIONS OF THE LAKE AS CAA KICKS
IN...EXPECT THE STRONGER WINDS TO MIX DOWN AS H850 WINDS ARE AROUND
35 KNOTS. WILL HAVE TO KEEP AN EYE ON THIS THROUGH LATER SHIFTS.
SATURDAY THROUGH MONDAY...BOTH THE EC AND GFS KEEP THE UPPER LEVEL
500MB TROUGH SITUATED OVER MUCH OF THE UPPER GREAT LAKES
REGION...HELPING TO KEEP ON AND OFF CHANCES OF SHOWERS IN THE
FORECAST THROUGH MONDAY AFTERNOON. THE BEST CHANCE OF RAIN SHOWERS
THROUGH THIS PERIOD WOULD BE MONDAY AS A SURFACE LOW APPROACHES THE
AREA FROM THE WEST. MOISTURE THROUGH THIS TIME PERIOD APPEARS TO BE
FAIRLY LIMITED AS A SURFACE HIGH WILL REMAIN JUST TO THE SOUTH OF
THE REGION KEEPING DRY WESTERLY WINDS PUSHING INTO THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 734 PM EDT MON AUG 13 2012
LINGERING SHRA ASSOCIATED WITH COLD FRONT PASSING THRU THE AREA WILL
END AT KSAW WITHIN THE NEXT COUPLE OF HRS. OTHERWISE...VFR
CONDITIONS WILL PREVAIL AT KIWD/KCMX/KSAW DURING THE NIGHT.
HOWEVER...WITH RAINFALL THAT OCCURRED TODAY AT KSAW...LIGHT/CALM WIND
AND MAINLY CLR SKIES SHOULD ALLOW RADIATIONAL FOG TO DEVELOP AT KSAW
LATE IN THE NIGHT. INCLUDED AN IFR VIS FOR NOW. VFR CONDITIONS WILL
PREVAIL AT KIWD/KCMX TUE...BUT A PERIOD OF MVFR CIGS IS EXPECTED IN
THE MORNING AT KSAW AS CU DEVELOP. COULD BE AN AFTN SHRA AT
KSAW...BUT POTENTIAL IS TOO LOW TO INCLUDE WITH THIS FCST ISSUANCE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT MON AUG 13 2012
QUIET MARINE WEATHER THROUGH WEDNESDAY AS HIGH PRESSURE SLIDES
OVERHEAD. BY LATER THURSDAY...PASSAGE OF A STRONG COLD FRONT WILL
KICK UP NORTHWEST WINDS TO 25 KTS OVER MUCH OF THE LAKE. WINDS TO 30
KTS ARE EXPECTED OVER CENTRAL AND EASTERN SECTIONS AS COLDER AIRMASS
PUSHES ACROSS THE STILL WARMER WATERS OF LAKE SUPERIOR. THE UNSTABLE
PROFILE WILL LEAD TO BUILDING WAVES THURSDAY NIGHT INTO FRIDAY.
EXPECT THE STRONG WINDS AND HIGH WAVES TO CONTINUE INTO SATURDAY
BEFORE DIMINISHING WITH ARRIVAL OF HIGH PRESSURE. EXPECT THE HIGHER
WAVES TO LEAD TO AN INCREASED RISK OF RIP CURRENTS LATE THURSDAY
THROUGH FRIDAY ALONG THE BEACHES OF EASTERN LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KEC
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
113 AM EDT SUN AUG 12 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 407 PM EDT SAT AUG 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER SRN
ONTARIO...JUST WEST OF TORONTO...SLOWLY LIFTING TO THE NORTHEAST.
UPSTREAM...A SHORTWAVE TROUGH WAS LOCATED OVER SE MT LEAVING WEAK
RIDGING FROM MN INTO WRN LAKE SUPERIOR. AT THE SFC...A RIDGE EXTENDED
FROM JAMES BAY THROUGH NE MN INTO IA AHEAD OF A TROUGH OVER THE WRN
PLAINS.
TONIGHT...AS HIGH PRES BUILDS INTO THE REGION AND DAYTIME HEATING
FADES...ANY REMAINING CU WILL DIMINISH THIS EVENING. THE AIRMASS
WILL ALSO BE RELATIVELY DRY WITH PWAT VALUES AOB 0.50 INCH.
WITH FAVORABLE RADIATIONAL COOLING CONDITIONS TONIGHT...LOW TEMPS
WILL DROP TO THE LOWER 40S OVER THE INTERIOR W...WITH LOWS AROUND 50
OVER THE INTERIOR E. NEAR THE GREAT LAKES SHORES...LOWS WILL BE IN
THE 50S TO NEAR 60. CANNOT RULE OUT SOME GROUND FOG AGAIN OVER THE WEST
BUT SHOULD BE PATCHY/ISOLATED.
SUNDAY...THE MODELS WERE CONSISTENT IN KEEPING THE PLAINS SHORTWAVE
FAR ENOUGH TO THE SOUTHWEST OF THE CWA TO KEEP UPPER MI DRY. EVEN
THOUGH THERE WILL BE INCREASING OVER THE WEST HALF DURING THE
AFTERNOON ON THE NRN FRINGE OF THE SHRTWV FORCING...A DECENT AMOUNT OF
SUNSHINE ALONG WITH WEAK WA WILL HELP PUSH TEMPS BACK INTO THE MID
TO UPPER 70S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 407 PM EDT SAT AUG 11 2012
UPPER MS VALLEY UPPER TROUGH WILL CROSS THE UPPER GREAT LAKES SUNDAY
NIGHT INTO MONDAY. MOISTURE WILL BE LIMITED AND BEST FORCING WILL
BE WELL SOUTH OF THE AREA CLOSER TO THE SURFACE LOW TRACKING ACROSS
NORTHERN IL INTO LOWER MI. WILL KEEP LOW CHANCE POPS ACROSS THE
AREA LATE SUNDAY NIGHT THROUGH MONDAY. LAKE BREEZES COULD BE THE
FOCUS FOR SOME ADDED SHRA AND ISOLATED TSRA DEVELOPMENT MONDAY
AFTERNOON.
SURFACE LOW WILL CONTINUE EAST INTO SOUTHERN ONTARIO ON TUESDAY WITH
HIGH PRESSURE BUILDING INTO WEST AND CENTRAL UPPER MI. RIDGE AXIS
WILL PASS OVER THE AREA EARLY WEDNESDAY WITH WINDS TURNING TO THE
SOUTHWEST DURING THE AFTERNOON. WITH PLENTY OF SUNSHINE THIS SHOULD
BE THE WARMEST DAY OF THE WEEK WITH TEMPS NEAR 80 IN MANY AREAS.
NEXT UPPER TROUGH AND COLD FRONT WILL BEGIN TO APPROACH THE AREA
FROM THE WEST BY LATE IN THE DAY INTO WEDNESDAY NIGHT. THIS SHOULD
OFFER UP A DECENT CHANCE OF RAIN ACROSS MUCH OF THE AREA AHEAD OF
THE FRONT. SEVERE WEATHER CHANCES APPEAR TO BE MINIMAL BUT EXPECT AT
LEAST A BROKEN BAND OF SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF
THE FRONT FROM WEDNESDAY NIGHT INTO THURSDAY.
AFTER THE FRONT PASSES AND WINDS TURN NORTHWESTERLY...DECENT COLD
ADVECTION WILL LOWER 85H TEMPS INTO THE 2-4C RANGE. THUS...EXPECT
SOME EARLY FALL LIKE CONDITIONS WITH POST FRONTAL LAKE EFFECT CLOUDS
AND EVEN SOME LAKE INDUCED SHRAS FROM LATE THURSDAY INTO FRIDAY.
SURFACE RIDGE AXIS WILL PASS OVER THE AREA ON SATURDAY WITH A
MODERATING TREND BEGINNING THEREAFTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 112 AM EDT SUN AUG 12 2012
UNDER DRY AIR MASS ASSOCIATED WITH HIGH PRES DRIFTING OVER THE UPPER
LAKES...VFR CONDITIONS WILL PREVAIL THRU THE FCST PERIOD AT
KIWD/KCMX/KSAW. THERE MAY BE SOME SHALLOW RADIATIONAL FOG AT KIWD
OVERNIGHT...SIMILAR TO LAST NIGHT...BUT SCT HIGH CLOUDS SHOULD HELP
LIMIT OCCURRENCE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT SAT AUG 11 2012
AS HIGH PRESSURE BUILDS INTO THE REGION...WINDS WILL SLOWLY DIMINISH
THROUGH TONIGHT. WINDS SUN THRU WED WILL BE MOSTLY 15KT OR LESS AS
ONLY WEAK SYSTEMS AFFECT THE AREA. A FALL-LIKE LOW PRESSURE SYSTEM
AND FRONT MOVING THROUGH LAKE SUPERIOR THURSDAY COULD PRODUCE
STRONGER NW WINDS INTO THE 20-30 KT RANGE FROM THURSDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1053 PM CDT MON AUG 13 2012
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW...
&&
.DISCUSSION.../ISSUED 258 PM CDT MON AUG 13 2012/
MAIN FORECAST ISSUES ARE LINGERING SHRA/TSRA EARLY THIS EVENING...
THEN CHANCES FOR SOME SHRA/TSRA FROM LATE TUESDAY NIGHT THROUGH
EARLY THURSDAY. THINGS HAVE CHANGED LITTLE IN THE BIG PICTURE...
WITH THE LONGWAVE UPPER RIDGE REMAINING ALONG OR OFF THE WEST
COAST THROUGH THE FORECAST PERIOD WHILE THE LONGWAVE TROUGH
PERSISTS OVER THE CENTRAL AND EASTERN PART OF THE CONTINENT. THERE
IS SLIGHTLY MORE AGREEMENT IN THINGS PERHAPS SHIFTING EAST AGAIN
AS WE HEAD THROUGH NEXT WEEK... WITH THE GFS AND ECMWF BOTH
SUGGESTING THE RIDGE WILL TRY TO SHIFT EAST AND PERHAPS MODERATE
TEMPERATURES ACROSS OUR AREA ONCE AGAIN. BUT... THAT IS STILL JUST
BEYOND THE FORECAST TIME FRAME FOR TODAY... SO NOT YET AN ISSUE
WITH WHICH WE NEED TO CONTEND. THE MAIN FEATURE OF INTEREST FOR US
IS A HEALTHY SHORTWAVE CURRENTLY SEEN ON WATER VAPOR ALONG THE
BRITISH COLUMBIA COAST... WHICH WILL DIVE SOUTHEAST OVER THE NEXT
FEW DAYS AND THEN WORK ACROSS THE NORTHERN PLAINS AND UPPER
MIDWEST WEDNESDAY INTO THURSDAY. THIS WILL FIRST WORK TO BRING A
BRIEF SURGE OF WARMTH/MOISTURE INTO OUR AREA LATE TUESDAY NIGHT
INTO WEDNESDAY... BEFORE HELPING TO FORCE A SHARP COLD FRONT
ACROSS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT.
TODAY THROUGH TUESDAY...AFTERNOON SURFACE ANALYSIS IDENTIFIED A WEAK
PRESSURE TROUGH EXTENDING FROM THE U.P. OF MICHIGAN DOWN THROUGH
SOUTHEASTERN MINNESOTA. MEANWHILE ALOFT WV IMAGERY AND 500 HEIGHTS
SHOWED LARGE SCALE NORTHWEST FLOW WITH A VERY SUBTLE SHORTWAVE
EMBEDDED WITHIN THIS FLOW ACROSS CENTRAL MINNESOTA. A VAST
CUMULUS FIELD BLANKETED ALL OF THE UPPER MISSISSIPPI RIVER VALLEY
DESPITE THE WEAK FORCING. A FEW SHOWERS WITH EVEN SOME LIGHTNING HAD
DEVELOPED MAINLY ACROSS WESTERN WISCONSIN IN THE AREA OF BETTER LOW
LEVEL CONVERGENCE CLOSER TO THE PRESSURE TROUGH. AFTERNOON SPC
MESOANALYSIS IDENTIFIED NEARLY 1000J/KG OF ML CAPE IN THIS
REGION...BUT THE LACK OF SHEAR AND FORCING RESULTED IN ONLY SPORADIC
ISOLATED CONVECTION. THESE SHOWERS/THUNDERSHOWERS SHOULD GRADUALLY
SHIFT SOUTHEAST DURING THE EVENING HOURS...AND TAPER OFF AROUND
SUNSET AS THE DIURNAL HEATING END. SKIES WILL CLEAR OVERNIGHT AND
WINDS WILL BECOME LIGHT AND VARIABLE AS AN AREA OF SURFACE HIGH
PRESSURE SETTLES ACROSS THE REGION. LATER TONIGHT A FEW
THUNDERSTORMS ARE POSSIBLE ACROSS THE HIGH PLAINS OF THE WESTERN
DAKOTAS...BUT THESE SHOULD REMAIN OUT WEST WHERE THE LOW LEVEL
THETA_E ADVECTION IS MORE FAVORABLE. THEREFORE ON TUESDAY NOT
EXPECTING MUCH MORE THAN PERHAPS SOME CIRRUS NEAR THE MN/SD UNTIL
THE NEXT WEATHER MAKER MOVES IN FOR THE MIDDLE OF THE WEEK.
THE SURFACE HIGH WILL SHIFT EAST OF THE AREA BY TUESDAY NIGHT...
WITH RETURN FLOW SETTING UP ACROSS THE WEST BEFORE WEDNESDAY
MORNING. THE NAM AND GFS SHOW SOME ISENTROPIC ASCENT INTO THE WEST
PRIOR TO 12Z WEDNESDAY NEAR THE LEADING EDGE OF THE APPROACHING
850MB THETA-E RIDGE. 850-500MB DIFFERENTIAL THETA-E VALUES QUICKLY
BECOME NEGATIVE AS THE BETTER LOW LEVEL MOISTURE WORKS IN... ANY
PCPN WHICH CAN DEVELOP ON THIS LEADING EDGE OF WARM ADVECTION
COULD CERTAINLY BE CONVECTIVE IN NATURE... ALTHOUGH THERE DOESN/T
APPEAR TO BE TOO MUCH IN THE WAY OF MUCAPE OR EFFECTIVE SHEAR SO
DO NOT ANTICIPATE ANY VIGOROUS STORMS IN THIS INITIAL BAND OF
POSSIBLE SHRA/TSRA LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS
INITIAL AREA OF PCPN POTENTIAL OWING TO WARM ADVECTION AND THE
INITIAL MOISTURE SURGE SHOULD QUICKLY MOVE NORTH/EAST WEDNESDAY
MORNING... WITH LITTLE TO SUPPORT PCPN OVER OUR AREA FOR MUCH OF
WEDNESDAY. ATTENTION THEN TURNS TOWARD THE APPROACHING SHORTWAVE
TROUGH AND COLD FRONT... WHICH WILL MARCH EAST ACROSS THE AREA
WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. THERE ARE STILL SOME
DIFFERENCES IN TIMING BETWEEN THE GFS... NAM... AND ECMWF... WITH
THE ECMWF STILL BEING THE SLOWEST IN ITS EASTWARD PROGRESSION OF
THE SYSTEM. THERE IS ALSO SOME QUESTION AS TO HOW FAR SOUTH ALONG
THE FRONT SHRA/TSRA WILL DEVELOP... WITH THE GFS BEING MOST
AGGRESSIVE IN LIGHTING UP PCPN ALONG THE ENTIRE BOUNDARY. THE
ECMWF MANAGES TO DEVELOP THINGS SOUTH THROUGH OUR CWFA... BUT
LACKS SUFFICIENT LARGE SCALE FORCING AND LOW LEVEL CONVERGENCE TO
DEVELOP MUCH OF ANYTHING SOUTH OF THE IOWA BORDER. THE NAM IS MORE
SIMILAR TO THE ECMWF... AND SUGGESTS A BREAK IN THE SOUTHWARD
DEVELOPMENT OF PCPN OVER OUR AREA WITH PERHAPS SOME ADDITIONAL
ACTIVITY FARTHER SOUTH WHERE IT HAS A SECONDARY JET MAX NEAR THE
NEBRASKA/KANSAS BORDER. AT THIS POINT MANY OF THESE DIFFERENCES IN
THE MODEL DETAILS APPEAR TO BE DUE TO THEIR DIFFERENT HANDLING OF
CONVECTIVE DEVELOPMENT NOT ONLY WHEN THE SYSTEM IS IN OUR AREA...
BUT PARTICULARLY UPSTREAM PRIOR TO IT ARRIVING. WITH THAT IN
MIND... DO NOT HAVE COMPLETE FAITH IN ANY PARTICULAR SOLUTION...
BUT CERTAINLY FEEL FROM THE LARGE SCALE PERSPECTIVE THAT THE BEST
CHANCES FOR PCPN WILL BE OVER THE NORTHERN PART OF THE AREA...
WITH LESSER CHANCES FARTHER SOUTH. IF/WHEN STORMS DEVELOP WE WILL
HAVE SOME POTENTIAL FOR SEVERE WEATHER GIVEN THE ANTICIPATED
MLCAPE VALUES AOA 1500 J/KG... DEEP LAYER SHEAR ON THE ORDER OF
35-45KT... AND 0-2KM BULK SHEAR AOA 20KT OUT AHEAD OF THE COLD
FRONT. THE PRIMARY SEVERE WEATHER THREAT WOULD APPEAR TO BE
DAMAGING WIND GUSTS WITH PERHAPS INITIALLY DISCRETE MULTICELLS OR
SUPERCELLS GROWING UPSCALE INTO A LINEAR/BOWING SYSTEM WITH TIME.
OF COURSE... THERE IS MUCH TIME BETWEEN NOW AND WEDNESDAY... AND
MANY THINGS COULD COMPLICATE THE PICTURE... INCLUDING TIMING OF
THE BOUNDARY... LINGERING CLOUD COVER FROM WARM ADVECTION
CONVECTION... STRONGER/WEAKER LOW LEVEL SHEAR... ETC. HOWEVER...
THERE IS CERTAINLY A CONTINUED NEED TO KEEP AN EYE ON THE
POTENTIAL FOR SOME SEVERE WEATHER ACROSS THE AREA FROM WEDNESDAY
AFTERNOON INTO WEDNESDAY NIGHT.
SOME SHRA COULD LINGER INTO EARLY THURSDAY ON THE BACKSIDE OF THE
UPPER TROUGH WITH DECENT LAPSE RATES IN PLACE AS THE MID-LEVEL
COLD POOL ARRIVES AND SOME LOW LEVEL CYCLONIC FLOW REMAINS. BUT...
HIGH PRESSURE ARRIVES IN EARNEST BY THURSDAY AFTERNOON... WHICH
SHOULD WORK TO SCOUR OUT ANY LINGERING PCPN. THIS FEATURE SHOULD
PROVIDE FOR FAIR AND DRY CONDITIONS THROUGH THE BALANCE OF THE
WORKWEEK. BY THE WEEKEND THERE MAY BE SOME CHANCE FOR SHRA/TSRA
AGAIN AS WE GET ONTO THE BACKSIDE OF THE SURFACE HIGH AND SOME
INSTABILITY TRIES TO CREEK BACK INTO THE AREA AND A FEW WEAK
SHORTWAVES DROP SOUTHEAST ON THE PREVAILING NORTHWEST UPPER FLOW.
INCLUDED SOME CHANCE POPS TO ACCOUNT FOR THOSE POSSIBILITIES...
MAINLY TAKING THE CONSENSUS OF SOMEWHAT SIMILAR SOLUTIONS FROM THE
GFS AND ECMWF.
&&
.AVIATION.../06Z TAF ISSUANCE/
PREVALENT SURFACE HIGH PRESSURE WILL YIELD LIGHT WINDS AND VFR
CONDITIONS THROUGH THE PERIOD...WITH THE EXCEPTION OF THE
POSSIBILITY OF A PERIOD OF FOG BETWEEN 09Z AND 13Z. CONCERN MAINLY
LIES OVER WEST CENTRAL WI AND SOUTH CENTRAL MN /KEAU-KRNH-
KRWF/...WHERE MEASURABLE PRECIP FELL MONDAY AND THE RAP INDICATES
DEWPOINT DEPRESSIONS DECREASE TO AROUND 2 OVERNIGHT. DO NOT THINK
IT WILL BE A CRYSTAL CLEAR SKY OVERNIGHT...WITH SHORT TERM MODELS
INDICATING LINGERING MOISTURE CIRCA 850MB...WHICH WAS CONFIRMED BY THE
00Z MPX RAOB. THEREFORE EXPECT SCATTERED CLOUDS AROUND 6K FEET
MIGHT ABATE SOME OF THE FOG RISK...PARTICULARLY AT KRWF. HAVE
THEREFORE MAINTAINED ONLY MINOR MVFR VSBY REDUCTIONS AT KRWF AND
KRNH. LIFR VSBYS OR EVEN BRIEF VLIFR VSBYS APPEAR LIKELY AT KEAU WHERE
A HALF INCH OF RAIN FELL MONDAY AFTERNOON. THE REMAINDER OF THE
TAF PERIOD WILL FEATURE FEW-SCT CUMULUS NEAR KRNH AND KEAU...AND
INCREASING MID/HIGH CLOUDS FROM WEST TO EAST AS THE NEXT SYSTEM
APPROACHES.
KMSP...VFR THROUGH THE PERIOD WITH LIGHT AND VARIABLE WINDS UNDER
THE INFLUENCE OF HIGH PRESSURE. DIRECTIONAL COMPONENT WILL BE
NORTHWESTERLY ON TUESDAY. WINDS WILL BACK TO SOUTH/SOUTHEAST IN DIRECTION
AND MID CLOUDS WILL BEGIN TO INCREASE AFTER 00Z WED AS A SURFACE
TROUGH APPROACHES.
/OUTLOOK/
.WEDNESDAY...VFR WITH MVFR AND TSRA POSSIBLE EARLY MORNING AND
AGAIN AT NIGHT. NIGHT COLD FROPA BTWN 00Z AND 06Z. WINDS S AT
10G15KTS SHIFTING TO NW 10G15KTS WITH THE FROPA.
.THURSDAY...VFR. WINDS BECOMING NW AT 15G25KTS.
.FRI...VFR. WINDS NW AOB 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LRS/JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
315 AM CDT SUN AUG 12 2012
.DISCUSSION...
MAIN CONCERN TODAY IS EXTENT OF SHRA AND ISOLATED THUNDER ACROSS
THE REGION. WATER VAPOR IMAGERY SHOWING RATHER VIGOROUS TROUGH
MOVING ACROSS CENTRAL/EASTERN DAKOTAS THIS MORNING. LIGHT RAIN
LIFTED NORTHEAST A BIT EARLIER THAN ORIGINALLY THOUGHT...BUT HAS
SLOWED EASTWARD PROGRESS AFTER MIDNIGHT. THE MINNESOTA RIVER
VALLEY LOOKS LIKE GROUND ZERO FOR MUCH OF THE MORNING. FOLLOWED
MORE OF A GFS/ECMWF TRACK OF TROUGH...WITH THE GREATEST RAIN
THREAT LOCATED MAINLY ALONG AND SOUTH OF INTERSTATE 94. WILL CARRY
CAT POPS VICINITY OF THE MN RIVER VALLEY THIS MORNING...AND DROP
IT SOUTH THIS AFTERNOON AS THE TROUGH MOVES SOUTHERLY SOUTHEAST.
STRONG LAYERED FGEN REMAINS ACROSS THIS REGION...INTO THE SOUTHERN
METRO INTO THIS AFTERNOON. 305K ISENTROPIC SURFACE SHOWS THIS
POTENTIAL AS WELL...AS THE STRONGER ISENTROPIC OMEGA LIFTS FROM
THE MN RIVER VALLEY THIS MORNING...INTO THE SOUTHERN METRO BY
AFTERNOON. THUNDER THREAT IS RATHER LIMITED. SOME INSTABILITY
DEVELOPS INTO FAR SOUTHERN MINNESOTA BY AFTERNOON...PER GFS.
FOLLOWED THE 21Z SREF 1 HOUR CONVECTIVE FORECAST GUIDANCE FOR
MENTIONING ISOLD THUNDER...MAINLY FOR THIS AFTERNOON ACROSS FAR
SOUTHERN MINNESOTA. MAY HAVE TO INCLUDE SOME ISOLD IN THE MORNING
IN THE SOUTHWEST AS WELL. WITH THE CLOUD COVER AND SHOWERS
AROUND...TEMPERATURES WILL BE HELD IN THE 60S IN THE SOUTHWEST.
THIS SYSTEM MOVES OUT TONIGHT. MODELS RETAIN THE SECONDARY COLD
FRONT SCENARIO FOR MONDAY...AS IT MOVES SOUTHEAST ACROSS THE
REGION INTO THE AFTERNOON. INSTABILITY INCREASES INTO THE
AFTERNOON AHEAD OF THE FRONT...WITH SOME WEAK CONVERGENCE LIMITED
TO MAINLY WEST CENTRAL WISCONSIN. WILL HOLD ONTO SMALL CHANCE POPS
THERE INTO THE AFTERNOON.
HIGH PRESSURE AND DRY CONDITIONS FOLLOW THIS SYSTEM FOR MONDAY
NIGHT AND TUESDAY. SEVERAL DETERMINISTIC MODELS INDICATE A
LEADING SHORT WAVE MOVING ACROSS THE DAKOTAS TUESDAY NIGHT...IN
CONCERT WITH SOME RETURN FLOW WAA SPREADING INTO THE CENTRAL CWA.
THE 00Z ECWMF HOLDS ONTO ITS RIDGE INTO WEDNESDAY...KEEPING
TUESDAY NIGHT DRY. WILL HOLD ONTO SOME LOW END POPS OVER THE
NORTHWEST CWA FOR NOW. THE MAIN SHOW WITH THIS SYSTEM WILL BE
LATER WEDNESDAY AND WEDNESDAY NIGHT AS THE UPPER TROUGH AND
ASSOCIATED SURFACE FRONT MOVES THROUGH.
COOL/DRY HIGH PRESSURE DROPS ACROSS THE GREAT LAKES REGION/UPPER
MIDWEST THEN THURSDAY NIGHT THROUGH THE WEEKEND. SLIGHT WARMING TREND
LATE IN THE WEEKEND AS THE HIGH MOVES EAST.
&&
.AVIATION.../06Z TAF ISSUANCE/
WINTER LIKE SYSTEM COMING AT THE MPX AREA FROM SODAK LOOKS TO
SPREAD SHOWERS ACROSS MANY OF THE TAF SITES THIS PERIOD. 00Z GFS
ALONG WITH THE 21Z SREF WERE FOLLOWED IN THE MAKING OF THESE
TAFS...SO WENT A BIT MORE PESSIMISTIC THAN THE 00Z TAFS...
ESPECIALLY FOR STC/MSP. STILL HAVE LOTS OF DRY AIR THAT NEEDS TO
BE OVERCOME OVERNIGHT FOR PRECIP TO MAKE IT THROUGH GROUND...BUT
WITH 700 MB LOW PROGGED TO GO FROM NEAR ABR NOW TO THE WI/IL/IA
TRI-STATE ARE BY 06Z MON...MOST OF THE MPX AREA WILL BE IN A
PROLONGED AREA OF FORCING AND LIFT. THIS WILL LIKELY KEEP VIRGA
GOING FOR MUCH OF THE NIGHT WHICH WILL ALLOW ENOUGH MOISTENING
TO HAVE OCCURRED BY THE MORNING TO PUSH RAIN OUT CLOSE TO THE MS
RIVER. AS WAS SEEN ACROSS THE DAKOTAS YESTERDAY...NO CONVECTION IS
EXPECTED WITH THIS ACTIVITY...BUT AS THE 700 MB LOW MOVES ACROSS
SRN MN...WE WILL LIKELY SEE MVFR CIGS DEVELOP. LAMP SPREADS THESE
CIGS UP TO ALL BUT THE WI TERMINALS BY THE AFTERNOON...THOUGH
LOOKING AT 925-850 MB RH FROM THE GFS AND SREF MVFR CIG
PROBS...SUB VFR CIGS MAY STAY SOUTH OF ALL BUT RWF. WILL SEE SE/E
WINDS PICK UP ACROSS MN TONIGHT AS A SFC LOW HEADS FOR SE
SODAK...TURNING TOWARD THE NW BY THE END OF THE TAF AS THIS LOW
HEADS EAST OF OUR LONGITUDE. WI TERMINALS MAY NOT SEE MUCH WIND AT
ALL THIS PERIOD AS THEY REMAIN IN A BIT OF A CUL.
KMSP...CONFIDENCE WITH RAIN THIS PERIOD NOT HELPED OUT BY THE FACT
THAT NOTHING HAS REALLY BEEN ABLE TO KEEP UP WITH THE PACE WITH
WHICH RAIN HAS BEEN PUSHING EAST ACROSS THE STATE. HOWEVER...LOOKS
LIKE VERY DRY AIR ASSOCIATED WITH HIGH PRESSURE STILL OVERHEAD HAS
REALLY PUT THE BREAKS ON THINGS THE LAST COUPLE OF HOURS...SO HELD
OF -RA MENTION UNTIL CLOSER TO WHEN THE HRRR BRINGS IT IN.
CERTAINLY COULD COME IN MUCH SOONER THAT 14Z IF RETURNS TO THE
WEST CONTINUE THERE TREND OF MAKING IT THROUGH ALL THAT DRY
AIR. OF COURSE WITH THE DRY AIR...MSP MAY NOT SEE MUCH MORE THAN
VIRGA UNTIL CLOSER TO 18Z. AT ANY RATE...ONCE THE -RA
STARTS...WILL LIKELY BE 4-7 HOURS OF FAIRLY CONTINUOUS STRATUS
PRECIP...WITH CIGS SLOWLY DESCENDING TOWARD MVFR LEVELS DURING THE
AFTERNOON. 925 RH FROM THE GFS WOULD SUGGEST MVFR CIGS MAY MISS
THE FIELD TO THE SOUTH...BUT THERE IS TIME TO MODIFY THIS IF NEED
BE.
OUTLOOK...
.MONDAY...VFR. NW WINDS 5-10 KTS.
.TUESDAY...VFR. VARIABLE WINDS 5 KTS.
.WEDNESDAY...TSRA LIKELY OVERNIGHT. S WINDS 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1216 AM CDT SUN AUG 12 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.EVENING FORECAST UPDATE...
/ISSUED AT 955 PM CDT SAT AUG 11 2012/
PLAYING CATCH UP WITH POP/WEATHER GRIDS THIS EVENING AS PRECIP HAS
COME IN MUCH FASTER THAN WHAT EVEN THE 12Z GUIDANCE HAD IT DOING.
LEADING EDGE OF PRECIP MOVING INTO MN HIGHLIGHTED WELL BY FGEN IN
THE H7-H6 LAYER OFF THE RAP...ALONG WITH OMEGA ON THE -15C
ISOTHERM. OF COURSE COMPLICATING ALL OF THIS IS THE VERY DRY
AIRMASS OVERHEAD DUE TO DEPARTING HIGH...AS EVIDENCED BY THE 00Z
KMPX SOUNDING...WHICH STILL HAD A PWAT OF 0.7 INCHES. THIS DRY AIR
SHOULD SLOW THE EWRD PROGRESSION OF THE SHOWERS. FOLLOWING THE
RAP FORECAST FOR FGEN/OMEGA MENTIONED ABOVE...SHOULD SEE PRECIP
SHIELD /WHERE RAIN IS ACTUALLY REACHING THE SURFACE/ BE NEAR AN
ALBERT LEA...TO THE WEST TWIN CITIES METRO...TO ST. CLOUD LINE BY
AROUND 12Z. THIS TIMING ALSO AGREES WITH 23Z HRRR REFLECTIVITY
FORECAST...WHICH DOES NOT LOOK TO FAR OFF FROM REALITY WHEN
COMPARING TO OBS /IF ANYTHING IT IS A BIT SLOW/. OTHER CHANGE MADE
TO GRIDS WAS TO REMOVE ANY MENTION OF THUNDER TONIGHT...AS WE DID
NOT SEE ANY THUNDER ACROSS THE CENTRAL DAKOTAS WITH THIS ACTIVITY
SATURDAY AND DO NOT SEE WHY ANY INSTABILITY WOULD MATERIALIZE
TONIGHT.
&&
.PREV DISCUSSION...
/ISSUED 702 PM CDT SAT AUG 11 2012/
OVERVIEW...ONLY SIGNIFICANT FORECAST CHALLENGE IN THE COMING DAYS
LIES WITH THE SYSTEM CURRENTLY MOVING INTO THE DAKOTAS...WHICH WILL
AFFECT THE SENSIBLE WEATHER IN MINNESOTA AND PERHAPS EVEN FAR
WESTERN WI OVER THE NEXT 30 HOURS. COOL AND RAINY WEATHER IS ALMOST
GUARANTEED FROM WEST CENTRAL TO SOUTH CENTRAL MINNESOTA ON SUNDAY.
CONTINUED NORTHWEST FLOW AND COOLER THAN NORMAL TEMPERATURES WILL BE
AT WORK ALL THE WAY THROUGH THE EXTENDED. AFTER SUNDAY...NEXT CHANCE
FOR RAIN DOES NOT ARRIVE UNTIL MID WEEK WHEN A SURFACE TROUGH AND
COLD FRONT PASS THROUGH THE AREA.
IF ALL GOES WELL TODAY...WE WILL HAVE OUR RADAR BACK BY THIS EVENING
AND WE CAN ALL WATCH TOGETHER AS THE RAIN SHIELD ADVANCES INTO
MINNESOTA FROM THE DAKOTAS. PROBABLY A LITTLE BIT HIGHER CONFIDENCE
WITH THE FORECAST DONE TODAY GIVEN THE TIGHTER CLUSTERING OF MODEL
SOLUTIONS COMPARED TO THE LAST COUPLE DAYS. MOST NOTABLE CHANGE
PROBABLY COMES WITH THE NORTHERN JUMP OF THE SURFACE REFLECTION IN
THE 11.12Z NAM. THE EC HAS BEEN ON THE NORTHERN SIDE OF THE MODEL
SPREAD...GFS - VERY CONSISTENTLY SOMEWHERE IN THE MIDDLE...AND THE
NAM HAS BEEN PRETTY FAR SOUTH. SO...WITH THE NORTHERN JUMP ON THE
NAM...THERE IS HIGHER CONFIDENCE IN WESTERN AND SOUTHERN MN GETTING A
SOLID 6-12 HOURS OF DEFORMATION BANDED RAINFALL.
CURRENT WATER VAPOR IMAGERY AND 500MB RUC ANALYSIS SUGGEST THE UPPER
WAVE NOW COMING OUT OF THE NORTHERN ROCKIES IS NOT BEING COMPLETELY
MISHANDLED BY EITHER THE NAM/GFS/EC. HOWEVER...WOULD HAVE TO SAY
THAT THE 11.12Z NAM/UKMET ARE PROBABLY JUST A TOUCH BETTER THAN THE
EC/GFS...WHICH HAVE THE GREATEST HEIGHT FALLS AND LOW CENTER JUST A
BIT TOO FAR TO THE NORTHEAST AT 18Z TODAY. AT ANY RATE...INCREASED
POPS TO 90-100% IN WEST CENTRAL AND SOUTH CENTRAL MN...AS IT IS HARD
TO IMAGINE A SITUATION WHERE MEASURABLE RAIN BY PASSES THESE AREAS.
THE 700MB LOW TRACK AND 850-700MB FGEN...WHICH IS QUITE GOOD...ARE
BOTH FAVORABLE FOR A WIDESPREAD 0.25" OR MORE IN THESE AREAS. THERE
IS NOT GREAT CONVECTIVE POTENTIAL...SO DON`T THINK WE WILL SEE MANY
LOCATIONS GET NEAR 1"...BUT THERE SHOULD BE A LOT OF 0.50" TOTALS IN
AREAS THAT SORELY NEED THE RAIN. STILL MEAGER MUCAPE SHOWING UP AND
IT IS AUGUST SO STILL INCLUDED SLIGHT CHANCE OF THUNDER IN THE
FORECAST.
MUCH BIGGER QUESTION MARK FOR AREAS IN EAST CENTRAL MN AND WESTERN
WI. ALTHOUGH THIS SYSTEM HAS TRENDED A BIT STRONGER AND FARTHER
NORTH...LOCATIONS ON THE NORTH SIDE OF THE BEST BANDED PRECIP MAY
ONLY END UP WITH A TENTH OR A FEW HUNDREDTH. THIS INCLUDES THE TWIN
CITIES METRO. THE 11.12Z GFS HAS A QPF BULLSEYE MUCH FURTHER NORTH
THAN MOST OF THE OTHER GUIDANCE...BUT GET THE FEELING THIS IS A
BIT AGGRESSIVE AND THAT THE LOCATION OF THE LOW LEVEL FGEN AND QG
FORCING A BIT FURTHER SOUTH WILL ANCHOR THE RAIN MORE IN WESTERN
AND SOUTHERN MN. STILL INCREASED POPS FOR THE LIKELIHOOD OF AT
LEAST A FEW HUNDREDTHS IN MANY AREAS TOMORROW.
AS MENTIONED PREVIOUSLY...WE WILL SEE BRIEF RIDGING FOR TUESDAY AS
THE NEXT STRONG TROUGH MOVES INTO THE REGION FOR WEDNESDAY
AFTERNOON/WEDNESDAY NIGHT. THERE IS MUCH BETTER CONVECTIVE
POTENTIAL WITH THIS SYSTEM. SHOULD SEE MUCH COOLER CONDITIONS
FOLLOWING THIS TROUGH INTO THE WEEKEND.
&&
.AVIATION.../06Z TAF ISSUANCE/
WINTER LIKE SYSTEM COMING AT THE MPX AREA FROM SODAK LOOKS TO
SPREAD SHOWERS ACROSS MANY OF THE TAF SITES THIS PERIOD. 00Z GFS
ALONG WITH THE 21Z SREF WERE FOLLOWED IN THE MAKING OF THESE
TAFS...SO WENT A BIT MORE PESSIMISTIC THAN THE 00Z TAFS...
ESPECIALLY FOR STC/MSP. STILL HAVE LOTS OF DRY AIR THAT NEEDS TO
BE OVERCOME OVERNIGHT FOR PRECIP TO MAKE IT THROUGH GROUND...BUT
WITH 700 MB LOW PROGGED TO GO FROM NEAR ABR NOW TO THE WI/IL/IA
TRI-STATE ARE BY 06Z MON...MOST OF THE MPX AREA WILL BE IN A
PROLONGED AREA OF FORCING AND LIFT. THIS WILL LIKELY KEEP VIRGA
GOING FOR MUCH OF THE NIGHT WHICH WILL ALLOW ENOUGH MOISTENING
TO HAVE OCCURRED BY THE MORNING TO PUSH RAIN OUT CLOSE TO THE MS
RIVER. AS WAS SEEN ACROSS THE DAKOTAS YESTERDAY...NO CONVECTION IS
EXPECTED WITH THIS ACTIVITY...BUT AS THE 700 MB LOW MOVES ACROSS
SRN MN...WE WILL LIKELY SEE MVFR CIGS DEVELOP. LAMP SPREADS THESE
CIGS UP TO ALL BUT THE WI TERMINALS BY THE AFTERNOON...THOUGH
LOOKING AT 925-850 MB RH FROM THE GFS AND SREF MVFR CIG
PROBS...SUB VFR CIGS MAY STAY SOUTH OF ALL BUT RWF. WILL SEE SE/E
WINDS PICK UP ACROSS MN TONIGHT AS A SFC LOW HEADS FOR SE
SODAK...TURNING TOWARD THE NW BY THE END OF THE TAF AS THIS LOW
HEADS EAST OF OUR LONGITUDE. WI TERMINALS MAY NOT SEE MUCH WIND AT
ALL THIS PERIOD AS THEY REMAIN IN A BIT OF A CUL.
KMSP...CONFIDENCE WITH RAIN THIS PERIOD NOT HELPED OUT BY THE FACT
THAT NOTHING HAS REALLY BEEN ABLE TO KEEP UP WITH THE PACE WITH
WHICH RAIN HAS BEEN PUSHING EAST ACROSS THE STATE. HOWEVER...LOOKS
LIKE VERY DRY AIR ASSOCIATED WITH HIGH PRESSURE STILL OVERHEAD HAS
REALLY PUT THE BREAKS ON THINGS THE LAST COUPLE OF HOURS...SO HELD
OF -RA MENTION UNTIL CLOSER TO WHEN THE HRRR BRINGS IT IN.
CERTAINLY COULD COME IN MUCH SOONER THAT 14Z IF RETURNS TO THE
WEST CONTINUE THERE TREND OF MAKING IT THROUGH ALL THAT DRY
AIR. OF COURSE WITH THE DRY AIR...MSP MAY NOT SEE MUCH MORE THAN
VIRGA UNTIL CLOSER TO 18Z. AT ANY RATE...ONCE THE -RA
STARTS...WILL LIKELY BE 4-7 HOURS OF FAIRLY CONTINUOUS STRATUS
PRECIP...WITH CIGS SLOWLY DESCENDING TOWARD MVFR LEVELS DURING THE
AFTERNOON. 925 RH FROM THE GFS WOULD SUGGEST MVFR CIGS MAY MISS
THE FIELD TO THE SOUTH...BUT THERE IS TIME TO MODIFY THIS IF NEED
BE.
OUTLOOK...
.MONDAY...VFR. NW WINDS 5-10 KTS.
.TUESDAY...VFR. VARIABLE WINDS 5 KTS.
.WEDNESDAY...TSRA LIKELY OVERNIGHT. S WINDS 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/MPG
AREA FORECAST DISCUSSION
NWS GLASGOW MT
249 PM MDT SUN AUG 12 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY...
SYNOPTIC SET UP... A LARGE HEAT DOME EXTENDS OVER THE SOUTHWESTERN
QUADRANT OF THE UNITED STATES WITH A RIDGE SPUR RUNNING UP
THROUGH THE PACIFIC NORTHWEST AND INTO BRITISH COLUMBIA. A LARGE
TROUGH STRETCHES FROM THE NORTHWESTERN TERRITORIES THROUGH SOUTHERN
MANITOBA AND INTO THE UPPER MISSISSIPPI VALLEY. THIS HAS PLACED
NEMONT IN A NORTHWESTERN FLOW ALOFT. AT THE SURFACE A LARGE DRY...
COOL...AND SEMI-STABLE AIRMASS HAS SET UP SHOP OVER HIGH PLAINS
AND IS MODIFYING. FURTHER WEST ANOTHER LARGE TROUGH EXISTS SOUTH
OF ALASKA AND IS MOVING ONTO THE BRITISH COLUMBIAN SHORE.
THIS EVENING... AFTERNOON HEAT HAS HELP TO WARM UP THE LOWER ATMOSPHERE
JUST ENOUGH TO REINDUCE CONDITIONAL INSTABILITY INTO THE NORTHWEST
FLOW ALOFT. THIS IS SHOWING UP ACROSS SOUTHERN ALBERTA ON
SATELLITE AND CANADIAN RADARS. HRRR MODEL PROJECTS THIS TO DROP
SOUTH THROUGH BLAINE COUNTY AND INTO OUR CWA AND THEN DIE OFF JUST
BEFORE MIDNIGHT. PHILLIPS... PETROLEUM... AND GARFIELD COUNTY ARE
THE MOST LIKELY TO RECEIVE ANY OF THIS BANDED PRECIPITATION. QPF
IS UNKNOWN DUE TO NARROW BANDING POTENTIAL AND STRENGTH OF THE
BANDS. BEST GUESS FOR ANY ISOLATED LOCATIONS THAT DO SEE PRECIP
WOULD BE WELL LESS THAN AN TENTH OF AN INCH.
MONDAY... CONDITIONS SHOULD BE FAIRLY SIMILAR TO TODAY INCLUDING
SEASONAL TEMPERATURES WITH PARTLY CLOUDY SKIES AND A MOSTLY DRY
AFTERNOON.
MONDAY NIGHT THROUGH TUESDAY... A PROGRESSION OF SYNOPTIC FEATURES
IS ANTICIPATED WITH THE PACIFIC NORTHWEST RIDGE MOVING OVER MONTANA
OVERNIGHT AND THEN INTO EASTERN MONTANA AND THE DAKOTAS BY
TUESDAY. THE BC TROUGH WILL EXIT THE FRONTRANGE OVERNIGHT AND THEN
TAP INTO THE ARCTIC AIRMASS BUILDING OVER NUNAVUT... CREATING AN
EXPRESS LANE DOWN THE CANADIAN PRAIRIES FOR ONE WHOPPER OF A COLD
FRONT. COMPRESSIONAL WARMING OUT AHEAD OF THE COLD FRONT WILL SHOW
UP TUESDAY MORNING AND LAST INTO THE AFTERNOON HOURS. HAVE KEPT
GRIDS ON THE WARM SIDE THROUGHOUT THESE PERIODS TO ACCOUNT FOR
THIS... WITH DAYTIME HIGHS ABOVE NORMAL FOR THIS TIME OF YEAR. THE
COLD FRONT WILL HIT IN THE LATE AFTERNOON/EVENING AND MAY HAVE A
CHANCE AT PRODUCING AS MUCH THUNDER AS REGULAR RAIN SHOWERS EARLY
ON. GAH
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
STILL ANTICIPATING COLD FRONT TO SWEEP THROUGH MONTANA EARLY
TUESDAY NIGHT. PRECIPITATION WILL BE ASSOCIATED WITH THE 700MB
TROF WHICH DROPS OUT OF CANADA INTO NORTHERN MONTANA AFTER
MIDNIGHT AND WILL TAKE UNTIL WEDNESDAY AFTERNOON TO PUSH OUT OF
SOUTHERN MONTANA. FOLLOWING THE FRONT COLD HIGH PRESSURE SETTLES
INTO THE NORTHERN PLAINS FOR TEMPERATURES ABOUT 20 DEGREES COOLER
ON WEDNESDAY AND THURSDAY COMPARED TO TUESDAY.
UPPER RIDGE REBOUNDS INTO THE PACIFIC NORTHWEST LATE IN THE WEEK
THEN SLIDES ACROSS THE NORTHERN ROCKIES OVER THE WEEKEND. THIS
WILL RESULT IN DRY BUT STEADILY WARMING TEMPERATURES THROUGH THE
END OF THE EXTENDED PERIOD. EBERT
&&
.AVIATION...
MOSTLY VFR CONDITIONS EXPECTED OVER THE NEXT 24 HOURS. WINDS WILL
TURN FROM NORTH TO EAST OVERNIGHT AS HIGH PRESSURE SLIDES ACROSS
CENTRAL CANADA BUT WILL REMAIN FAIRLY LIGHT UNTIL MID MORNING ON
MONDAY. RAE
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1127 PM MDT SAT AUG 11 2012
.UPDATE...
A SMALL AREA OF SHOWERS AND THUNDERSTORMS DEVELOPED ALONG HIGHWAY 87
NEAR FORT BENTON AROUND 1030 PM MDT AS A WEAK UPPER-LEVEL SHORTWAVE
COMBINED WITH INCREASED LOW-LEVEL MOISTURE. SMALL HAIL...GUSTY WINDS
AND BRIEF HEAVY RAINFALL ARE POSSIBLE WITH THESE STORMS. THIS
ACTIVITY IS CURRENTLY SHIFTING SOUTH AND ADDITIONAL THUNDERSTORMS
MAY DEVELOP IN AN AREA EXTENDING ALONG I-15 FROM SHELBY TO GREAT
FALLS AND EAST ALONG MT-200 TOWARDS LEWISTOWN. THUNDERSTORMS WILL
DIMINISH EARLY SUNDAY MORNING. MLV
.DISCUSSION...
UPDATE FORTHCOMING. HAVE KEPT LOW POPS ACROSS THE NORTHEAST CORNER
OF THE COUNTY WARNING AREA THROUGH MIDNIGHT. THOUGH NOTHING
APPEARING ON RADAR AT THE MOMENT...THE MODELS AND HRRR ANALYSIS ALL
HAVE QPF SLIDING SOUTH OUT OF CANADA AND ACROSS THE NORTHEAST PRIOR
TO MIDNIGHT. CONVECTIVE ACTIVITY SHOULD END AFTER MIDNIGHT WITH
CLEARING SKIES AFFORDING A DECENT VIEW OF THE PERSEIED METEOR SHOWER.
EMANUEL
&&
.AVIATION...
UPDATED 0430Z.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. SCATTERED CLOUDS
WILL BE POSSIBLE NEAR THE CANADIAN BORDER AND IN THE ROCKY MOUNTAIN
FRONT. A FEW CLOUDS WILL REDEVELOP ON SUNDAY AND POSSIBLY A FEW
THUNDERSTORMS...MAINLY IN THE MOUNTAINS OF NORTH CENTRAL MONTANA.
LANGLIEB
&&
.PREV DISCUSSION...ISSUED 303 PM MDT SAT AUG 11 2012
TONIGHT THROUGH MONDAY...A NORTHWESTERLY FLOW ALOFT COMBINED WITH
BREEZY NORTHERLY UPSLOPE WINDS FROM A CANADIAN SURFACE HIGH
BUILDING SOUTH OVER THE AREA HAS CAUSED LOW-TOPPED CONVECTION TO
DEVELOP. ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE THROUGH
AROUND 9 PM MDT OR SO...BUT THEY SHOULD BE FAIRLY WEAK.
OTHERWISE...THE CLOUDS/SHOWERS/WINDS SHOULD DECREASE OVERNIGHT AS
AN UPPER LEVEL RIDGE OF HIGH PRESSURE BUILDS INTO THE AREA. A FEW
SHOWERS/THUNDERSTORMS MAY DEVELOP AGAIN OVER THE MOUNTAIN PEAKS
DURING THE PEAK HEATING OF THE AFTERNOON/EVENING HOURS OF SUNDAY
AND MONDAY. HOWEVER...THE UPPER LEVEL RIDGE IN PLACE WILL PREVENT
MUCH MOVEMENT OFF THE MOUNTAINS OF ANY SHOWERS/STORMS THAT MAY
DEVELOP. WINDS WILL SHIFT MORE EASTERLY ON SUNDAY AS THE SURFACE
HIGH SLIDES SOUTHEAST OF THE AREA...THEN THEY WILL BECOME MORE
SOUTHERLY ON MONDAY AS AN INVERTED SURFACE TROUGH MOVES INTO THE
AREA FROM THE WEST. TEMPERATURES ON SUNDAY WILL BE SIMILAR TO
TODAY (SLIGHTLY ABOVE NORMAL)...BUT THE WARMER AIR ASSOCIATED
WITH THE INVERTED SURFACE TROUGH WILL CAUSE TEMPERATURES TO WARM
TO 5 TO 10 DEGREES ABOVE NORMAL. COULSTON
MONDAY NIGHT THROUGH SATURDAY...PERIOD BEGINS WITH QUIET
CONDITIONS THROUGH TUES MORNING BEFORE A SHARP CANADIAN UPPER
LEVEL TROF AND ASSOCIATED COLD FRONT ARRIVES LATER THAT DAY.
STILL SEEING SOME SLIGHT TIMING DIFFERENCES ON THIS SYSTEM WITH
THE EUROPEAN MODEL BEING JUST A FEW HOURS QUICKER THAN THE GFS
MODEL...BUT OVERALL MODEL SOLUTIONS ARE SIMILAR IN SWEEPING THE
SYSTEM ACROSS CENTRAL AND SOUTHWEST MT FROM TUES THROUGH WED.
MOISTURE ACCOMPANYING THE TROF WILL GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS WITH GENERALLY LIGHT RAINFALL AMOUNTS AS
PRECIPITABLE WATER AMOUNTS ARE ONLY IN THE 0.7 TO 0.9 INCH RANGE.
MOST NOTICEABLE IMPACT WILL BE THE SIGNIFICANTLY COOLER
TEMPERATURES ON WED AS HIGHS ACROSS THE REGION WILL ONLY BE IN
THE MID 60S TO NEAR 70 DEGREES. AS THE CANADIAN SYSTEM EXITS INTO
ERN MT LATE WED...A STRONG RIDGE OF HIGH PRESSURE BUILDS INTO THE
GREAT BASIN AND NRN ROCKIES...BRINGING MOSTLY FAIR SKIES AND DRY
CONDITIONS FOR THURS THROUGH EARLY SAT AFTN. BY SAT AFTN THE
RIDGE AXIS DRIFTS EASTWARD...ALLOWING MONSOONAL MOISTURE TO
RETURN WITH A NEW ROUND OF SHOWERS AND THUNDERSTORMS CONTINUING
THROUGH SAT NIGHT. TEMPERATURES REMAIN PLEASANTLY COOL ON THURS
WITH HIGHS IN THE MID-UPPER 70S...THEN ARE EXPECTED TO CLIMB BACK
TO THE MID- UPPER 80S FOR FRI AND SAT. WARANAUSKAS
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 56 87 58 93 / 20 10 10 10
CTB 52 82 54 89 / 20 10 10 10
HLN 56 89 59 93 / 10 10 10 10
BZN 50 89 52 91 / 10 10 10 10
WEY 40 82 42 82 / 0 10 10 20
DLN 49 87 52 89 / 0 0 0 10
HVR 55 86 58 92 / 20 10 10 10
LWT 53 81 55 88 / 20 10 10 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1035 PM MDT SAT AUG 11 2012
UPDATED AVIATION SECTION
.DISCUSSION...
UPDATE FORTHCOMING. HAVE KEPT LOW POPS ACROSS THE NORTHEAST CORNER
OF THE COUNTY WARNING AREA THROUGH MIDNIGHT. THOUGH NOTHING
APPEARING ON RADAR AT THE MOMENT...THE MODELS AND HRRR ANALYSIS ALL
HAVE QPF SLIDING SOUTH OUT OF CANADA AND ACROSS THE NORTHEAST PRIOR
TO MIDNIGHT. CONVECTIVE ACTIVITY SHOULD END AFTER MIDNIGHT WITH
CLEARING SKIES AFFORDING A DECENT VIEW OF THE PERSEIED METEOR SHOWER.
EMANUEL
&&
.AVIATION...
UPDATED 0430Z.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. SCATTERED CLOUDS
WILL BE POSSIBLE NEAR THE CANADIAN BORDER AND IN THE ROCKY MOUNTAIN
FRONT. A FEW CLOUDS WILL REDEVELOP ON SUNDAY AND POSSIBLY A FEW
THUNDERSTORMS...MAINLY IN THE MOUNTAINS OF NORTH CENTRAL MONTANA.
LANGLIEB
&&
.PREV DISCUSSION...ISSUED 303 PM MDT SAT AUG 11 2012
TONIGHT THROUGH MONDAY...A NORTHWESTERLY FLOW ALOFT COMBINED WITH
BREEZY NORTHERLY UPSLOPE WINDS FROM A CANADIAN SURFACE HIGH
BUILDING SOUTH OVER THE AREA HAS CAUSED LOW-TOPPED CONVECTION TO
DEVELOP. ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE THROUGH
AROUND 9 PM MDT OR SO...BUT THEY SHOULD BE FAIRLY WEAK.
OTHERWISE...THE CLOUDS/SHOWERS/WINDS SHOULD DECREASE OVERNIGHT AS
AN UPPER LEVEL RIDGE OF HIGH PRESSURE BUILDS INTO THE AREA. A FEW
SHOWERS/THUNDERSTORMS MAY DEVELOP AGAIN OVER THE MOUNTAIN PEAKS
DURING THE PEAK HEATING OF THE AFTERNOON/EVENING HOURS OF SUNDAY
AND MONDAY. HOWEVER...THE UPPER LEVEL RIDGE IN PLACE WILL PREVENT
MUCH MOVEMENT OFF THE MOUNTAINS OF ANY SHOWERS/STORMS THAT MAY
DEVELOP. WINDS WILL SHIFT MORE EASTERLY ON SUNDAY AS THE SURFACE
HIGH SLIDES SOUTHEAST OF THE AREA...THEN THEY WILL BECOME MORE
SOUTHERLY ON MONDAY AS AN INVERTED SURFACE TROUGH MOVES INTO THE
AREA FROM THE WEST. TEMPERATURES ON SUNDAY WILL BE SIMILAR TO
TODAY (SLIGHTLY ABOVE NORMAL)...BUT THE WARMER AIR ASSOCIATED
WITH THE INVERTED SURFACE TROUGH WILL CAUSE TEMPERATURES TO WARM
TO 5 TO 10 DEGREES ABOVE NORMAL. COULSTON
MONDAY NIGHT THROUGH SATURDAY...PERIOD BEGINS WITH QUIET
CONDITIONS THROUGH TUES MORNING BEFORE A SHARP CANADIAN UPPER
LEVEL TROF AND ASSOCIATED COLD FRONT ARRIVES LATER THAT DAY.
STILL SEEING SOME SLIGHT TIMING DIFFERENCES ON THIS SYSTEM WITH
THE EUROPEAN MODEL BEING JUST A FEW HOURS QUICKER THAN THE GFS
MODEL...BUT OVERALL MODEL SOLUTIONS ARE SIMILAR IN SWEEPING THE
SYSTEM ACROSS CENTRAL AND SOUTHWEST MT FROM TUES THROUGH WED.
MOISTURE ACCOMPANYING THE TROF WILL GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS WITH GENERALLY LIGHT RAINFALL AMOUNTS AS
PRECIPITABLE WATER AMOUNTS ARE ONLY IN THE 0.7 TO 0.9 INCH RANGE.
MOST NOTICEABLE IMPACT WILL BE THE SIGNIFICANTLY COOLER
TEMPERATURES ON WED AS HIGHS ACROSS THE REGION WILL ONLY BE IN
THE MID 60S TO NEAR 70 DEGREES. AS THE CANADIAN SYSTEM EXITS INTO
ERN MT LATE WED...A STRONG RIDGE OF HIGH PRESSURE BUILDS INTO THE
GREAT BASIN AND NRN ROCKIES...BRINGING MOSTLY FAIR SKIES AND DRY
CONDITIONS FOR THURS THROUGH EARLY SAT AFTN. BY SAT AFTN THE
RIDGE AXIS DRIFTS EASTWARD...ALLOWING MONSOONAL MOISTURE TO
RETURN WITH A NEW ROUND OF SHOWERS AND THUNDERSTORMS CONTINUING
THROUGH SAT NIGHT. TEMPERATURES REMAIN PLEASANTLY COOL ON THURS
WITH HIGHS IN THE MID-UPPER 70S...THEN ARE EXPECTED TO CLIMB BACK
TO THE MID- UPPER 80S FOR FRI AND SAT. WARANAUSKAS
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 56 87 58 93 / 20 10 10 10
CTB 52 82 54 89 / 20 10 10 10
HLN 56 89 59 93 / 10 10 10 10
BZN 50 89 52 91 / 10 10 10 10
WEY 40 82 42 82 / 0 10 10 20
DLN 49 87 52 89 / 0 0 0 10
HVR 55 86 58 92 / 20 10 10 10
LWT 53 81 55 88 / 20 10 10 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...EMANUEL/COULSTON
LONG TERM...WARANAUSKAS
AVIATION...LANGLIEB
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
101 AM CDT SUN AUG 12 2012
.AVIATION...06Z KGRI TAF. VFR CEILING/VISIBILITY ARE FORECAST
THROUGH THE PERIOD...ALTHOUGH THERE ARE A FEW THINGS TO DISCUSS.
FIRST OFF...ALTHOUGH A BRIEF THUNDERSTORM IS STILL POSSIBLE MAINLY
WITHIN THE FIRST FEW HOURS TONIGHT...CONFIDENCE HAS GENERALLY
DECREASED IN THIS ACTIVITY DIRECTLY AFFECTING KGRI...AND THUS HAVE
REMOVED THE TEMPO GROUP BUT LEFT IN A VICINITY THUNDERSTORM
MENTION THROUGH 09Z. ATTENTION THEN TURNS TO INCREASING NORTH-
NORTHWEST WINDS. GENERALLY LIGHT/VARIABLE SPEEDS WILL PREVAIL
THROUGH THE FIRST SEVERAL HOURS...BEFORE A STEADY NORTH-NORTHWEST
WIND BECOMES ESTABLISHED BY MID-MORNING IN THE WAKE OF A COLD
FRONT...WITH SEVERAL HOURS OF GUST POTENTIAL TO AROUND 26KT. BY
SUNSET SUNDAY EVENING...GUSTINESS SHOULD SUBSIDE WITH SUSTAINED
SPEEDS EASING BELOW 12KT. AS FOR CEILING TRENDS...COULD SEE AT
LEAST A FEW HOURS OF BROKEN CEILING AROUND 4-5 THOUSAND FEET
DURING THE LAST 12-15 HOURS OF THE PERIOD AS STRATUS ROTATES SOUTH
ALONG THE BACKSIDE OF THE DEPARTING LOW PRESSURE SYSTEM...BUT THIS
CLOUD DECK IS EXPECTED TO REMAIN AT LEAST SLIGHTLY ABOVE MVFR
THRESHOLDS IF IT IN FACT MATERIALIZES.
&&
.PREV DISCUSSION... /ISSUED 408 PM CDT SAT AUG 11 2012/
SHORT TERM...THROUGH 00Z MONDAY. MORNING UPPER AIR ANALYSIS
INDICATES UPPER LEVEL RIDGING OVER THE SOUTHWESTERN CONUS AND
TROUGHING OVER THE EASTERN CONUS. A MID LEVEL SHORT WAVE IS ALSO
NOTED OVER EASTERN MONTANA. MID AND UPPER LEVEL JET ENERGY IS
SITUATED FROM THE NORTHWESTERN CONUS...EASTWARD INTO THE NORTHERN
PLAINS...AND THEN SOUTHEAST ACROSS THE MISSOURI AND MISSISSIPPI
VALLEYS ON INTO THE SOUTHEASTERN CONUS. THIS ~70KT UPPER LEVEL JET
AXIS REMAINS JUST TO THE EAST OF OUR CWA...MORE OVER EASTERN
NEBRASKA AND IOWA...THUS RESULTING IN FAIRLY WEAK TROPOSPHERIC
FLOW OVER SOUTH CENTRAL NEBRASKA AND NORTH CENTRAL KANSAS. WATER
VAPOR IMAGERY DOES NOT INDICATE A SUFFICIENT TROPICAL TAP OF MID
LEVEL MOISTURE ACROSS THE CENTRAL CONUS TODAY...BUT INCREASING MID
LEVEL MOISTURE IS NOTED OVER THE NORTHERN ROCKY MOUNTAIN RANGE AND
PORTIONS OF THE NORTHERN AND CENTRAL PLAINS AS THE MID LEVEL SHORT
WAVE...CURRENTLY OVER EASTERN MONTANA...APPROACHES FROM THE
NORTHWEST. THERE ALSO APPEARS TO BE A SUBTLE MID LEVEL
PERTURBATION WORKING ACROSS NEBRASKA AT THIS TIME AS WELL. AT THE
SURFACE A RIDGE OF HIGH PRESSURE IS NOTED OVER THE UPPER
MISSISSIPPI VALLEY...WITH LOW LEVEL RETURN FLOW ON THE BACK SIDE
OF THE RIDGE AXIS OVERTAKING MUCH OF THE CENTRAL PLAINS. A SURFACE
LOW IS ALSO NOTED OVER WESTERN NORTH DAKOTA...WITH AN ASSOCIATED
COLD FRONT EXTENDING SOUTH FROM THE LOW ACROSS THE NORTHERN AND
CENTRAL HIGH PLAINS.
WEAK FORCING AHEAD OF THE SUBTLE MID LEVEL PERTURBATION NOW
PUSHING ACROSS NEBRASKA IS HELPING PROMOTE ELEVATED PRECIPITATION
PRODUCTION ACROSS PORTIONS OF CENTRAL NEBRASKA...WITH RADAR DATA
FROM KUEX INDICATING ISOLATED TO SCATTERED RETURNS ACROSS NORTHERN
PORTIONS OF OUR CWA AS OF 20Z. THAT BEING SAID...PRECIPITATION
REPORTS HAVE BEEN HARD TO COME BY WITH THIS ACTIVITY WITH
PROXIMITY SOUNDINGS ACROSS OUR CWA PER RAP ANALYSIS INDICATING
PLENTY OF LOW LEVEL DRY AIR IN PLACE. STILL...QPF FIELDS FROM THE
11/12Z NAM AND OPERATIONAL GFS...AS WELL AS THE 11/12Z EC AND
11/09Z SREF-MEAN...ALL SUGGEST AT LEAST SOME PRECIPITATION WILL BE
REALIZED AT THE SURFACE ACROSS PORTIONS OF OUR WESTERN AND
NORTHERN CWA THROUGH 00Z THIS EVENING. GIVEN THE CURRENT RETURNS
FROM AREA RADARS...AS WELL AS THE ABOVE-MENTIONED MODEL
OUTPUT...WENT AHEAD AND INSERTED 20% POPS ACROSS THE NORTHERN TWO-
THIRDS OF OUR CWA THROUGH THIS EVENING. AS MENTIONED EARLIER...LOW
LEVEL MOISTURE VALUES ARE FAIRLY LOW AS OF EARLY AFTERNOON WITH
SURFACE DEW POINTS ACROSS OUR CWA GENERALLY IN THE 50S. THIS IS
HELPING KEEP INSTABILITY ON THE WEAK SIDE ACROSS SOUTH CENTRAL
NEBRASKA AND NORTH CENTRAL KANSAS. THAT BEING SAID...THE NAM DOES
INDICATE 0-1KM MLCAPE VALUES WILL INCREASE TO ~500J/KG ACROSS OUR
NORTHERN CWA LATER THIS AFTERNOON AS MID LEVEL LAPSE RATES
UNDERNEATH THE MID LEVEL PERTURBATION INCREASE. CHANCES FOR SEVERE
WEATHER THIS AFTERNOON AND EVENING APPEAR VERY LOW DUE TO THE
OVERALL LACK IN INSTABILITY...BUT THE RAP ANALYSIS PROXIMITY
SOUNDINGS ALSO INDICATE VERY DEEP INVERTED-V SOUNDINGS ACROSS MUCH
OF THE CWA WHICH WILL BE CONDUCIVE FOR BRIEF DOWN BURSTS DESPITE
THE GENERALLY WEAK CONVECTION. GIVEN ALL THIS...WILL ALSO GO AHEAD
AND INTRODUCE STRONG STORM WORDING...BRIEF WIND GUSTS TO AROUND 50
MPH...TO THE HWO FOR THIS AFTERNOON AND EVENING...AGAIN PRIMARILY
FOR LOCATIONS ACROSS OUR NORTHERN CWA.
SHOWERS WITH EMBEDDED THUNDERSTORMS SHOULD INCREASE IN AERIAL
COVERAGE ACROSS OUR CWA AS THE MAIN MID LEVEL SHORT WAVE
APPROACHES FROM EASTERN MONTANA. PLENTY OF DPVA AND MID LEVEL
THERMAL ADVECTION AHEAD OF THE MID LEVEL TROUGH AXIS SHOULD
PRESENT A DECENT PRECIPITATION SHIELD SOMEWHERE OVER THE
REGION...WITH QPF FIELDS FROM THE 11/12Z NAM...OPERATIONAL
GFS...EC...AS WELL AS THE 11/09Z SREF-MEAN...11/12Z 4KM WRF-
NMM...AND 11/16Z HRRR ALL SUGGESTING THE MOST LIKELY AREA OF
MEASURABLE PRECIPITATION IS LOCATED FROM NORTH CENTRAL NEBRASKA
INTO EASTERN NEBRASKA...WITH THESE BEST CHANCES FOR PRECIPITATION
CLIPPING OUR NORTHEASTERN CWA...ALTHOUGH ITS IMPORTANT TO REMEMBER
PRECIPITATION CHANCES ARE IN THE FORECAST FOR THE ENTIRE CWA. THE
NAM SUGGESTS OVERNIGHT DEEP LAYER MUCAPE VALUES OF AROUND 100J/KG
WILL BE REALIZED ACROSS PORTIONS OF THE AREA TONIGHT...AND WITH
THE AMOUNT OF DPVA AND MID LEVEL THERMAL ADVECTION INFILTRATING
THE AREA TONIGHT...WOULD EXPECT MORE OF A STRATIFORM RAIN EVENT
WITH EMBEDDED CONVECTIVE CLUSTERS WITHIN THE MAIN PRECIPITATION
SHIELD. WENT AHEAD WITH ONLY AN ISOLATED THUNDER MENTION IN THE
FORECAST FOR TONIGHT AS A RESULT...WITH NOTHING IN THE WAY OF
SEVERE WEATHER CURRENTLY EXPECTED. PRECIPITATION SHOULD QUICKLY
COME TO AN END SUNDAY MORNING AS THE MID LEVEL TROUGH AXIS CLEARS
THE AREA BY 12Z SUNDAY AND SUBSIDENCE QUICKLY INFILTRATES THE AREA
THROUGH THE REMAINDER OF SUNDAY.
THE SURFACE LOW...CURRENTLY OVER WESTERN NORTH DAKOTA...IS
EXPECTED TO MOVE SOUTHEAST ACROSS THE DAKOTAS AND INTO THE
MISSOURI AND MISSISSIPPI VALLEYS OVERNIGHT TONIGHT INTO TOMORROW.
THE ASSOCIATED COLD FRONT WILL ALSO MOVE SOUTHEAST AND IS EXPECTED
TO PUSH ACROSS OUR CWA DURING THE DAY SUNDAY. THAT BEING SAID
THERE ARE INDICATIONS...ESPECIALLY FROM THE NAM...THAT THE TRUE
LOW LEVEL COLD AIR ADVECTION WILL LIKELY HOLD OFF UNTIL THE
AFTERNOON AND EVENING HOURS ON SUNDAY BEFORE INFILTRATING OUR CWA.
THIS SCENARIO LOOKS A LOT LIKE THIS PAST WEDNESDAY WHERE WE HAD A
WIND SHIFT TO THE WEST/NORTHWEST AND THIS DOWN-SLOPING
WIND...WHICH ALLOWED THE LOW LEVEL AIRMASS TO DRY OUT VERY QUICKLY
BUT ALSO EFFICIENTLY HEAT UP AS THE COOLER AIR REMAINED WELL NORTH
OF THE AREA...RESULTED IN A FORECAST WHICH PRESENTED AN
OVERWHELMING COLD BIAS WITH MANY LOCATIONS COMING DANGEROUSLY
CLOSE TO CRITICAL FIRE WEATHER CONDITIONS. GIVEN ALL THIS...OPTED
TO PLAY CLOSE TO NAM/MET GUIDANCE...WHICH BOIVERIFY INDICATES
PERFORMED THE BEST OF ANY MODEL HEADING INTO LAST WEDNESDAY...FOR
SUNDAY TEMPERATURES...DEW POINTS AND WINDS. AS A RESULT...THE
CURRENT FORECAST SHOWS AFTERNOON RELATIVE HUMIDITY VALUES IN THE
23%-25% RANGE ACROSS THE SOUTHWESTERN ONE-THIRD OF OUR CWA. BREEZY
CONDITIONS WILL ALSO BE OBSERVED POST-FROPA ON SUNDAY BUT WITH THE
COOLER AIR LAGGING WELL BEHIND...ACROSS THE NORTHERN PLAINS
THROUGH MUCH OF THE DAY...THE STRONGEST LOW LEVEL PRESSURE
GRADIENT AND RESULTANT STRONGEST WINDS SHOULD ALSO REMAIN
RELEGATED TO NORTHERN PORTIONS OF THE CWA. ALTHOUGH SUSTAINED
WINDS OF ~20KTS EXIST IN THE FORECAST FOR NORTHERN PORTIONS OF THE
CWA...FARTHER SOUTH WHERE SURFACE RELATIVE HUMIDITY VALUES WILL BE
LOWER...SUSTAINED WINDS ARE ONLY EXPECTED TO CLIMB INTO THE
14-16KT RANGE. SO...AT THIS TIME CRITICAL FIRE WEATHER CONDITIONS
ARE NOT FORECAST FOR SUNDAY...BUT THIS IS SOMETHING FUTURE SHIFTS
WILL CERTAINLY WANT TO MONITOR CLOSELY. WILL GO AHEAD AND
HIGHLIGHT NEAR CRITICAL FIRE WEATHER CONDITIONS ACROSS OUR
SOUTHWEST IN THE HWO TO GET THE WORD OUT. FINALLY...BOIVERIFY
INDICATES BCCONSRAW HAS BEEN DOING VERY WELL WITH RESPECT TO SHORT
TERM OVERNIGHT TEMPERATURE FORECASTS AND AS A RESULT...FOLLOWED
CLOSELY TO BCCONSRAW FOR OVERNIGHT LOWS TONIGHT.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. OVERALL THIS WILL BE A
COOL PERIOD WITH HIGH TEMPERATURES GENERALLY RUNNING BELOW NORMAL
ON MOST DAYS. IN ADDITION...THERE WILL BE SEVERAL CHANCES OF
SHOWERS AND THUNDERSTORMS.
SUNDAY NIGHT THROUGH MONDAY. AN UPPER TROUGH WILL TRACK FROM IOWA
INTO THE GREAT LAKES WITH COOL HIGH PRESSURE SETTLING INTO THE
REGION. THIS WILL ALSO RESULT IN DRY WEATHER. MONDAY SHOULD BE A
GREAT DAY AS THE WINDS BECOME LIGHT UNDER THE SFC HIGH PRESSURE
AND HIGH TEMPERATURES WILL RANGE FROM AROUND 80 OVER SOUTHERN
NEBRASKA TO THE MID 80S OVER NORTHERN KANSAS. DECIDED TO GO A
TOUCH BELOW GUIDANCE WITH HIGH TEMPERATURES OVER NEBRASKA ZONES.
MONDAY NIGHT THROUGH TUESDAY...A WEAK SHORT WAVE WILL TRACK
THROUGH THE CENTRAL PLAINS. HOWEVER...FORECAST MODELS ARE NOT IN
VERY GOOD AGREEMENT ON THE TRACK OF THIS SYSTEM. THE 12Z ECMWF
WOULD MAKE FOR A RATHER RAINY MONDAY NIGHT INTO TUESDAY WHILE THE
GFS IS LESS EXCITED ABOUT PRECIPITATION. TYPICALLY THIS HAS BEEN
THE OTHER WAY AROUND THIS SEASON WITH THE GFS SHOWING MORE QPF.
ULTIMATELY IT DEPENDS ON THE TRACK OF THE WAVE AND WILL CONTINUE
TO CARRY SLIGHT POPS FOR NOW AND WILL WAIT FOR BETTER MODEL
AGREEMENT BEFORE RAISING OR LOWING POPS DURING THIS PERIOD. THE
TIMING OF THIS WAVE WOULD PUT THE MOST LIKELY TIMING OF POSSIBLE
PRECIPITATION AFTER MIDNIGHT MONDAY NIGHT THROUGH THE FIRST HALF
OF TUESDAY.
WEDNESDAY AND THURSDAY...A STRONGER SHORT WAVE WITH A SHARP COLD
FRONT WILL TRACK ACROSS OUR FORECAST AREA WEDNESDAY INTO WEDNESDAY
EVENING. THIS WILL RESULT IN SCATTERED THUNDERSTORMS WITH A FEW
POSSIBLY STRONG STORMS. THUNDERSTORMS WILL FOR THE MOST PART HAVE
MOVED THROUGH BY THURSDAY MORNING...WITH A CHANCE OF POST FRONTAL
RAIN SHOWERS DURING THE DAY ON THURSDAY. WEDNESDAY WILL LIKELY BE
ONE OF THE HOTTER DAYS OF THE WEEK AND POSSIBLY THE ONLY DAY
DURING THE LONG TERM PERIOD WITH ABOVE NORMAL HIGHS. HOWEVER...THE
TIMING OF THE COLD FRONT MAY IMPACT HIGH TEMPERATURES ACROSS
NORTHERN ZONES AND WILL NEED TO BE WATCHED CLOSELY. TEMPERATURES
ON THURSDAY WILL ONLY BE IN THE 70S ACROSS NEBRASKA TO AROUND 80
OVER NORTHER KANSAS. THE NEW CONSALL TEMPERATURES ARE ACTUALLY
EVEN A FEW DEGREES COOLER WITH THURSDAY HIGHS.
FRIDAY AND SATURDAY...DRY WEATHER WILL RETURN WITH HIGH PRESSURE
SETTLING IN BEHIND THE DEPARTING STORM SYSTEM. HIGH TEMPERATURES
WILL SLOWLY WARM...BUT REMAIN COOLER THAN NORMAL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...PFANNKUCH
SHORT TERM...BRYANT
LONG TERM...WESELY
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
339 PM EDT SUN AUG 12 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL BUILD OVER EASTERN NORTH CAROLINA THROUGH
TUESDAY AS A WEAK FRONT REMAINS STALLED WELL NORTH OF THE AREA. A
COLD FRONT WILL MOVE INTO AREA WEDNESDAY WITH ANOTHER STRONGER
FRONT APPROACHING THE REGION ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OR 3 PM SUNDAY...WITH THE FRONTAL BOUNDARY STILL PARKED NEAR
THE RALEIGH AREA AND WITH MODERATE INSTABILITY OVER THE COASTAL
PLAINS WITH CAPE VALUES OF AROUND 2500 J/KG AND LI`S AROUND
-6...WILL KEEP A SLIGHT CHC OF SHOWERS/TSTMS IN THE FORECAST
THROUGH ABOUT 22Z THIS EVENING. SOMEWHAT DRIER AIR STARTS TO
FILTER INTO EASTERN NC THIS EVENING AND OVERNIGHT AS AXIS OF MID-
LEVEL TROUGH MOVES OFFSHORE. DESPITE THE OVERALL DRYING OF THE
COLUMN...STILL THINK GROUND MOISTURE WILL BE SUFFICIENT TO PRODUCE
SOME PATCHES OF FOG OR STRATUS TOWARD MORNING. OVERNIGHT LOW
TEMPERATURES WILL RANGE FROM 68 TO 74 DEGREES TONIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
AS OF 3 PM SUNDAY...PRECIPITABLE WATER VALUES DROP TO NEAR AN INCH
ON MONDAY AS SLIGHTLY DRIER AIR MOVES IN WITH DEWPOINTS INTO THE
UPPER 60S INLAND AND LOWER 70S CLOSER TO THE COAST. WITH STRONG
SUBSIDENCE AND LOW MEAN RH VALUES...EXPECT SKIES TO BE MOSTLY
SUNNY. HIGH TEMPERATURES FOR MONDAY WILL BE IN THE MIDDLE AND
UPPER 80S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
AS OF 315 PM SUN...LONG TERM PERIOD WILL START OUT DRY FOR TUE...
WITH PRECIP CHANCES FOR MID WEEK AND THEN AGAIN NEXT WEEKEND.
TEMPERATURES WILL BE NEAR NORMAL THROUGH THE PERIOD.
BRIEF RIDGING OCCURS TUE AS SHORTWAVE BYPASSES THE AREA WELL TO THE
NORTH. WEAK PIEDMONT THERMAL TROUGH WILL KEEP ANY THUNDERSTORM
CHANCES WEST OF THE COASTAL PLAIN.
ISO TO SCT THUNDERSTORM CHANCES ON WEDNESDAY AS FAST MOVING COLD
FRONT PASSES THROUGH ON LOW AMPLITUDE SHORTWAVE. THIS SYSTEM WILL BE
MOISTURE STARVED SO NOT EXPECTING MUCH IN THE WAY OF QPF.
TEMPORARY RIDGING TAKES HOLD FOR THUR...BEFORE NEXT IN SERIES OF
FAST MOVING SHORTWAVES MOVES IN FROM THE WEST ON FRI. HAVE INC POPS
JUST A BIT FRI AFTERNOON AS THIS ENERGY COMES IN ALONG WITH DECREASE
IN HEIGHT FIELD YIELDING BETTER CHANCE OF THUNDERSHOWERS. PRECIP
CHANCES COULD LINGER INTO SAT AS WE REMAIN IN THE WARM SECTOR.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
SHORT TERM /TONIGHT AND MONDAY/...
AS OF 305 PM SUNDAY...A FEW SHOWERS MAY AFFECT INLAND TAF SITES
OVER THE NEXT 2 OR 3 HOURS...BUT THE PRECIPITATION HAS...FOR THE
MOST PART...MOVED EAST OF THE AREA. DESPITE OVERALL DRYING OF THE
COLUMN AS THE UPPER TROUGH MOVES OFFSHORE THIS EVENING...THINK
THERE IS PLENTY OF GROUND MOISTURE AND NUMERICAL GUIDANCE HINTS AT
FOG LATE TONIGHT. ALSO THINK THERE COULD BE SOME STRATUS...SO WILL
FORECAST MVFR/IFR CONDITIONS LATE TONIGHT. MONDAY SHOULD BE VFR
WITH SUNNY AND DRY WEATHER EXPECTED.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 330 PM SUN...MAINLY VFR CONDITIONS THROUGH THE LONG TERM.
ISOLATED TO SCT STORMS ON WED POSSIBLE...WITH DRY CONDITIONS ON TUE
AND THUR. ANOTHER CHANCES OF PRECIP ON FRI. COULD BE SOME LATE
NIGHT/EARLY AM FOG/BR THROUGH THE PERIOD AS WINDS WILL BE LIGHT EACH
EVENING.
&&
.MARINE...
SHORT TERM /TONIGHT AND MONDAY/...
AS OF 310 PM SUNDAY...SEEING A BIT OF AN AFTERNOON SURGE WITH
WINDS HOVERING AROUND 15 KNOTS FROM OREGON INLET SOUTH. GFS/NAM12
AND RAP INDICATES THAT WINDS WILL DROP TO AROUND 10 KNOTS AGAIN BY
EVENING. SEAS SHOULD REMAIN IN THE 2 TO 4 FOOT REALM TONIGHT AND
MONDAY PER LATEST WAVEWATCH 4 AND LOCAL SWAN GUIDANCE.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 330 PM SUN...FAIRLY QUIET BOATING CONDITIONS THROUGH THE LONG
TERM. SW WINDS AROUND 10 KT WILL INC TO 15 TO OCNL GUSTS NEARING 20
KT TUE NIGHT IN ADVANCE OF COLD FRONT MOVING IN FROM THE WEST. WINDS
DIMINISH TO 15 KT OR LESS ON WED. WINDS COULD BRIEFLY TURN NORTHERLY
BEHIND FRONTAL PASSAGE WED NIGHT AND EARLY THUR...THOUGH WILL REMAIN
ON THE LIGHT SIDE. SW WINDS ONCE AGAIN FOR LATE THUR THROUGH THE
WEEKEND...AND WINDS AND SEAS INC LATE FRI INTO SAT AHEAD OF NEXT
FRONTAL PASSAGE. ATTM EXPECTING CRITERIA TO REMAIN SUB SCA.
&&
.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
909 AM EDT SUN AUG 12 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL BOUNDARY WILL APPROACH THE AREA TODAY AND
MOVE OFF THE COAST AND DISSIPATE TONIGHT. HIGH PRESSURE WILL BUILD IN
EARLY NEXT WEEK. ANOTHER COLD FRONT WILL PASS THROUGH THE REGION
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 905 AM SUNDAY...HAVE RAISED POPS A BIT ACROSS THE
SOUTHERN/SOUTHWESTERN CWA WITH WIDESPREAD SHOWERS AND TSTMS
DRIFTING NORTHEAST AS OF 13Z. COLD FRONT REMAINS JUST WEST OF THE
RALEIGH AREA WITH VERY MOIST AIRMASS IN PLACE AS PRECIPITABLE
WATER REMAINS ABOVE 2 INCHES. THE LATEST RAP MODEL SHOWS THE PRECIP
CONTINUING THROUGH LATE MORNING WITH ADDITIONAL SHOWERS AND TSTMS
FORMING INLAND DURING THE AFTERNOON...MUCH LIKE THE PAST FEW DAYS.
HAVE ALREADY UPDATED LATEST ZONES/GRIDS TO REFLECT SLIGHTLY HIGHER
POPS OVER THE SOUTH/SOUTHWESTERN CORRIDOR. NO OTHER MAJOR CHANGES
AT THIS TIME.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
AS OF 400 AM SUNDAY...ANY SHOWER AND THUNDERSTORM ACTIVITY THAT DOES
DEVELOP THIS AFTERNOON WILL PUSH TO AND OFF THE COAST BY AROUND
MIDNIGHT. WILL SEE SOME CLEARING SKIES BEHIND THE FRONT BUT NOT
ANY COOLER TEMPS WITH LOWS IN THE LOWER 70S MOST AREAS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 345 AM SUN...UPPER TROUGH/SURFACE FRONT SHOULD BE OFF THE EAST
COAST MON MORNING WITH SURFACE WINDS SHIFTING W TO NW BEHIND THE
FRONT. BRIEF RIDGING SURFACE AND ALOFT WILL BUILD IN FROM THE SW MON
AFTERNOON TO MON NIGHT WITH WINDS SHIFTING BACK SOUTHERLY BY THE
AFTERNOON HOURS. A STRONG SHORTWAVE TROUGH ALOFT WILL DEVELOP ACROSS
THE NORTHERN PLAINS STATES MON AND PUSH EAST TOWARDS THE GREAT LAKES
MON NIGHT INTO TUES...THEN DRAG A COLD/COOL FRONT THROUGH EASTERN NC
LATE TUES NIGHT INTO WED NIGHT. PWATS DROP BELOW 1 INCH BRIEFLY MON
NIGHT BUT QUICKLY BUILD BACK OVER 1.75 INCHES AS SOUTHERLY FLOW
KICKS IN TUES AFTERNOON...INDICATING HEAVY RAIN MAY BE PROBLEMATIC
WITH SHOWERS AND THUNDERSTORMS TUES NIGHT INTO WED. MINOR TWEAKS TO
PREVIOUS POPS/WX FORECAST TO REFLECT SMALL CHANGES IN ECMWF/NAM
GUIDANCE...AND HAVE MAINTAINED 35-40 PERCENT CHANCE POPS TUES NIGHT
THROUGH WED. LOW LEVEL THICKNESSES WILL RANGE 1410-1415 METERS MON
THROUGH WED WHICH WILL PRODUCE MAX TEMPS IN THE UPPER 80S TO LOWER
90S.
SURFACE RIDGE WILL BUILD IN FROM THE NW THURS BEHIND THE EXITING
FRONT...WITH ZONAL FLOW DEVELOPING ALOFT AND THUS KEPT THURS DRY.
THE RIDGE WILL SHIFT OFFSHORE FRI MORNING ALLOWING RETURN SURFACE
FLOW TO DEVELOP BY FRI MORNING AND INITIATED SLIGHT CHANCE POPS FRI
AFTERNOON FOR DIURNAL CONVECTION. LOW LEVEL THICKNESSES CONTINUE
1410-1415 METERS WITH CLEAR SKIES EXPECTED THURS...AND ALTHOUGH NW/N
SURFACE FLOW WILL BRIEFLY USHER IN COOLER AIR...MAX TEMPS WILL BUILD
INTO THE UPPER 80S. ANOTHER UPPER LEVEL TROUGH WILL DEVELOP ACROSS
THE NORTHERN PLAINS STATES FRI THEN AMPLIFY AS IT HEADS EAST TOWARDS
THE GREAT LAKES INTO SAT. ECMWF/GFS INDICATE A STRONG SHORTWAVE WILL
DEVELOP ACROSS THE CENTRAL MISSISSIPPI VALLEY AREA AHEAD OF THE MAIN
UPPER TROUGH FRI AND PUSH EAST TOWARDS EASTERN NC...BRINGING ANOTHER
CHANCE FOR SHOWERS AND THUNDERSTORMS FRI THROUGH SAT. ADJUSTED
POPS/WX TO BETTER REFLECT TRENDS IN THE EXTENDED ECMWF. ALTHOUGH THE
SHORTWAVE WILL PUSH ANOTHER COLD/COOL FRONT WILL CROSS THE REGION
FRI/SAT... LOW LEVEL THICKNESSES CHANGE LITTLE. CLOUD COVER AND
PRECIP WILL BE THE BIGGEST DETERMINING FACTOR BETWEEN LOWER 90S AND
UPPER 80S FRI/SAT.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 730 AM SUNDAY...AREA OF SHOWERS AND THUNDERSTORMS
APPROACHING FROM THE SOUTHWEST TODAY LOOKS LIKE IT WILL MOSTLY
AFFECT IMMEDIATE COASTAL AREAS. CONTINUED TO INCLUDE VCTS IN THE
OAJ TAF EARLY THIS MORNING TO REFLECT THAT. COULD SEE SOME ADDITIONAL
SHOWERS AND TSTMS FURTHER INLAND THIS AFTERNOON...DEVELOPING IN
THE VICINITY OF THE APPROACHING COLD FRONT. EXPECT SOME BREAKS IN
CLOUDS TODAY AND WITH DAYTIME HEATING MODERATE INSTABILITY MAY AID
IN TSTM DEVELOPMENT. EXPECT PERIODS OF MVFR IN HEAVIER TSTMS...BUT
CARRIED JUST VCTS IN TAFS WITH VFR CONDITIONS. EXPECT FOG TO BE
AN ISSUE TONIGHT WITH LIGHT WINDS AND CLEARING SKIES BEHIND THE
FRONT AND SIGNIFICANT LOW LEVEL MOISTURE GIVEN PROLONGED RAINY
PERIOD. CAPPED AT 3SM/MVFR CONDITIONS DUE TO REDUCED VISIBILITIES
IN FOG AFTER MIDNIGHT.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 330 AM SUN...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH THE
EXTENDED. ISOLATED TO SCATTERED CONVECTION POSSIBLE TUES NIGHT
THROUGH WED AS A COLD FRONT CROSSES THE REGION WHICH MAY BRIEFLY
REDUCE CEILINGS/VSBYS. HIGH PRESSURE WILL BUILD IN THURS WITH VFR
CONDITIONS EXPECTED.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 910 AM SUNDAY...SMALL CRAFT ADVISORY HAS EXPIRED OVER THE
CENTRAL WATERS WITH SEAS IN THE 2 TO 4 FOOT RANGE AS SW/WSW WINDS
CONTINUE AT 10 KNOTS OR LESS. WILL MAKE MINOR TWEAKS TO THE FIRST
PERIOD OF THE FORECAST. FOLLOWED CLOSE TO WW3 FOR SEAS.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 400 AM SUN...GRADIENT WILL DIMINISH EARLY MON WITH VARIABLE
WINDS EARLY BECOMING SOUTHERLY AGAIN BY MON AFTERNOON. EXPECT SW
WINDS 10-15 KNOTS MON NIGHT THROUGH TUES WITH WIND-WAVE DOMINATED SEAS
MOSTLY 2-3 FT. SE SWELL OF 2 FT AROUND 9 SECONDS WILL PERSIST MON
NIGHT THROUGH TUES AS WELL. A COLD FRONT WILL APPROACH THE WATERS
FROM THE WEST BY WED MORNING WITH SW PRESSURE GRADIENT TIGHTENING
SLIGHTLY AND WINDS COULD GUST NEAR SCA LEVELS...HOWEVER EXPECT
MOSTLY SW 10-20 KNOTS AND SEAS 3 TO 5 FT. THE FRONT WILL CROSS
LATE WED NIGHT INTO THURS WITH SHOWERS AND THUNDERSTORMS EXPECTED.
WINDS AND SEAS SUBSIDE AS HIGH PRESSURE BUILDS IN FROM THE NORTH
THURS ALTHOUGH WAVEWATCH III SPECTRAL GUIDANCE CONTINUES TO
INDICATE SE SWELL OF 2 FT AT 9 SECONDS PERSISTING WED INTO THURS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RSB
NEAR TERM...CTC
SHORT TERM...RSB
LONG TERM...DAG
AVIATION...RSB/DAG
MARINE...RSB/CTC/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
147 AM EDT SUN AUG 12 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL BOUNDARY WILL CROSS THE AREA LATE SUNDAY.
HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK. ANOTHER COLD FRONT
WILL PASS THROUGH THE REGION THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1210 AM SUNDAY...MAD SOME TWEAKS TO POP TO ACCOUNT FOR
ONGOING RADAR TRENDS AND LATEST RUC MODEL GUIDANCE. LOWERED POPS
INLAND TO AROUND 30...BUT INCREASED POPS BACK TO LIKELY ALONG THE
OUTER BANKS TO ACCOUNT FOR ONGOING SHOWERS AND POSSIBLE
REDEVELOPMENT JUST OFF THE COAST. TEMP FCST LOOKS GOOD WITH CLOUD
COVER AND LIGHT SOUTHERLY BREEZE KEEPING TEMPS FROM FALLING MUCH
MORE OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
AS OF 7 PM SAT...TRIMMED BACK POPS TO CHANCE IN THE MORNING BASED
ON LATEST GUIDANCE. MORE IN THE WAY OF SCT ACTIVITY EXPECTED IN
THE AFTERNOON AS FRONT PUSHES THROUGH TO THE COASTAL WATERS.
AIRMASS WILL REMAIN UNSTABLE...THOUGH LACK OF SIG FORCING WILL
PROHIBIT STORMS FROM BECOMING SEVERE ON SUNDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...AXIS OF MID-LEVEL TROUGH WILL BE MOVING
OFFSHORE SUNDAY NIGHT WITH SLIGHTLY DRIER AIR ADVANCING INTO
EASTERN NORTH CAROLINA ON MONDAY. DEWPOINTS WILL DROP INTO THE
60S...BUT TEMPERATURES WILL STILL WARM WELL INTO THE 80S TO AROUND
90 DEGREES. GFS SHOWS A SHORTWAVE TROUGH CROSSING THE AREA TUESDAY
AFTERNOON WITH A SLIGHT INCREASE IN MEAN RH AND A SLIGHT CHC POP
FOR MOST AREAS. A WEAK COLD FRONT WILL DROP INTO THE CWA ON
WEDNESDAY AND HAVE CONTINUED RECENT TREND OF LOW POPS THROUGH
WEDNESDAY AND NEAR THE COAST INTO WEDNESDAY NIGHT. UPPER FLOW
BECOMES MORE ZONAL WITH A DRY DAY EXPECTED ON THURSDAY. SOME TIME
DIFFERENCE BETWEEN GFS AND ECMWF FOR NEXT RAIN-MAKING SYSTEM WITH
THE ECMWF A BIT FASTER AND WETTER WITH DEEP MOISTURE AND PRECIP
AHEAD OF COLD FRONT...BUT STILL WILL SHOW A TREND OF INCREASING
POPS FRIDAY AND SATURDAY OF NEXT WEEK. OVERALL TEMPERATURES WILL
BE AT OR JUST A DEGREE OR TWO ABOVE NORMAL THROUGH THE NEXT
WEEK...BUT MOST OF THE WEEK WILL BE CHARACTERIZED BY SLIGHTLY
LOWER DEWPOINTS...ESPECIALLY MONDAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 130 AM SUNDAY...MOSTLY BROKEN TO OVERCAST MID AND HIGH
CLOUDS WILL PERSIST THROUGH THE MORNING HOURS. THERE WILL BE A
CHANCE OF SOME SHOWERS/TSTMS ALONG THE COAST EARLY THIS MORNING.
MODELS SHOW THIS TREND AND SEEING SOME SHOWER ACTIVITY FORM OVER
EASTERN SC THAT COULD MOVE UP THIS WAY BY DAYBREAK. ALLOWED FOR
THIS IN THE OAJ TAF WITH A VCTS. OTHERWISE BEST CHANCE OF SHOWERS
AND TSTMS WILL BE THIS AFTERNOON WITH FRONT LINGERING JUST TO OUR
WEST AND A WEAK SHRTWV THAT WILL MOVE ACROSS THE AREA. EXPECT SOME
BREAKS IN CLOUDS TODAY AND WITH DAYTIME HEATING MODERATE
INSTABILITY TO AID IN TSTM DEVELOPMENT. EXPECT PERIODS OF MVFR IN
HEAVIER TSTMS...BUT CARRIED JUST A VCTS IN TAFS WITH VFR
CONDITIONS AT THIS TIME.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 210 PM SATURDAY...WITH LOWER HUMIDITY LEVELS...WOULD EXPECT
MAINLY VFR CONDITIONS MONDAY. SOME ISOLATED CONVECTION POSSIBLE
TUESDAY WITH A SLIGHT BETTER CHANCE WEDNESDAY WITH A COLD FRONT
LINGERING OVER THE CWA AND SOME BRIEF REDUCTIONS OF MVFR POSSIBLE.
THE LOW-LEVEL DRY OUT AGAIN THURSDAY WITH ANOTHER VFR DAY LIKELY
AS USUAL...CANNOT RULE OUT SOME LATE NIGHT AND EARLY MORNING
STRATUS AND FOG WHICH MAY CAUSE BRIEF DROPS TO MVFR/IFR STATUS.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 10 PM SATURDAY...BASED ON OBS OVER THE COASTAL WATERS SOUTH
OF OCRACOKE AND ON THE PAMLICO SOUND I WILL DROP THE SMALL CRAFT
ADVISORY THAT WAS IN EFFECT UNTIL 03Z. WILL LEAVE SMALL CRAFT
DUE TO SEAS IN EFFECT NORTH OF OCRACOKE THROUGH 09Z.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 220 PM SATURDAY...MAY SEE A BRIEF UPTICK IN THE WINDS
TUESDAY NIGHT INTO EARLY WEDNESDAY AS GRADIENT TIGHTENS AHEAD OF
COLD FRONTAL BOUNDARY MOVING INTO NORTHERN SECTIONS BEFORE
DISSIPATING. OTHERWISE...SHOULD SEE SOUTHWEST WINDS OF 15 KNOTS OR
LESS AND SEAS GENERALLY 2 TO 4 FEET THROUGHOUT THE PERIOD. LATEST
WAVEWATCH 4 AND LOCAL SWAN IN DECENT AGREEMENT ON WAVEHEIGHTS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
AMZ150-152-154.
&&
$$
SYNOPSIS...TL
NEAR TERM...RSB
SHORT TERM...TL
LONG TERM...CTC
AVIATION...RSB/CTC
MARINE...CTC/HSA/TL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1215 AM EDT SUN AUG 12 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL BOUNDARY WILL CROSS THE AREA LATE SUNDAY.
HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK. ANOTHER COLD FRONT
WILL PASS THROUGH THE REGION THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1210 AM SUNDAY...MAD SOME TWEAKS TO POP TO ACCOUNT FOR
ONGOING RADAR TRENDS AND LATEST RUC MODEL GUIDANCE. LOWERED POPS
INLAND TO AROUND 30...BUT INCREASED POPS BACK TO LIKELY ALONG THE
OUTER BANKS TO ACCOUNT FOR ONGOING SHOWERS AND POSSIBLE
REDEVELOPMENT JUST OFF THE COAST. TEMP FCST LOOKS GOOD WITH CLOUD
COVER AND LIGHT SOUTHERLY BREEZE KEEPING TEMPS FROM FALLING MUCH
MORE OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
AS OF 7 PM SAT...TRIMMED BACK POPS TO CHANCE IN THE MORNING BASED
ON LATEST GUIDANCE. MORE IN THE WAY OF SCT ACTIVITY EXPECTED IN
THE AFTERNOON AS FRONT PUSHES THROUGH TO THE COASTAL WATERS.
AIRMASS WILL REMAIN UNSTABLE...THOUGH LACK OF SIG FORCING WILL
PROHIBIT STORMS FROM BECOMING SEVERE ON SUNDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...AXIS OF MID-LEVEL TROUGH WILL BE MOVING
OFFSHORE SUNDAY NIGHT WITH SLIGHTLY DRIER AIR ADVANCING INTO
EASTERN NORTH CAROLINA ON MONDAY. DEWPOINTS WILL DROP INTO THE
60S...BUT TEMPERATURES WILL STILL WARM WELL INTO THE 80S TO AROUND
90 DEGREES. GFS SHOWS A SHORTWAVE TROUGH CROSSING THE AREA TUESDAY
AFTERNOON WITH A SLIGHT INCREASE IN MEAN RH AND A SLIGHT CHC POP
FOR MOST AREAS. A WEAK COLD FRONT WILL DROP INTO THE CWA ON
WEDNESDAY AND HAVE CONTINUED RECENT TREND OF LOW POPS THROUGH
WEDNESDAY AND NEAR THE COAST INTO WEDNESDAY NIGHT. UPPER FLOW
BECOMES MORE ZONAL WITH A DRY DAY EXPECTED ON THURSDAY. SOME TIME
DIFFERENCE BETWEEN GFS AND ECMWF FOR NEXT RAIN-MAKING SYSTEM WITH
THE ECMWF A BIT FASTER AND WETTER WITH DEEP MOISTURE AND PRECIP
AHEAD OF COLD FRONT...BUT STILL WILL SHOW A TREND OF INCREASING
POPS FRIDAY AND SATURDAY OF NEXT WEEK. OVERALL TEMPERATURES WILL
BE AT OR JUST A DEGREE OR TWO ABOVE NORMAL THROUGH THE NEXT
WEEK...BUT MOST OF THE WEEK WILL BE CHARACTERIZED BY SLIGHTLY
LOWER DEWPOINTS...ESPECIALLY MONDAY.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 10 PM SATURDAY...EXPECTING MAINLY VFR CONDITIONS TONIGHT
THOUGH SOME MVFR AND IFR IN SCATTERED SHOWERS AND TSTMS.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 210 PM SATURDAY...WITH LOWER HUMIDITY LEVELS...WOULD EXPECT
MAINLY VFR CONDITIONS MONDAY. SOME ISOLATED CONVECTION POSSIBLE
TUESDAY WITH A SLIGHT BETTER CHANCE WEDNESDAY WITH A COLD FRONT
LINGERING OVER THE CWA AND SOME BRIEF REDUCTIONS OF MVFR POSSIBLE.
THE LOW-LEVEL DRY OUT AGAIN THURSDAY WITH ANOTHER VFR DAY LIKELY
AS USUAL...CANNOT RULE OUT SOME LATE NIGHT AND EARLY MORNING
STRATUS AND FOG WHICH MAY CAUSE BRIEF DROPS TO MVFR/IFR STATUS.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 10 PM SATURDAY...BASED ON OBS OVER THE COASTAL WATERS SOUTH
OF OCRACOKE AND ON THE PAMLICO SOUND I WILL DROP THE SMALL CRAFT
ADVISORY THAT WAS IN EFFECT UNTIL 03Z. WILL LEAVE SMALL CRAFT
DUE TO SEAS IN EFFECT NORTH OF OCRACOKE THROUGH 09Z.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 220 PM SATURDAY...MAY SEE A BRIEF UPTICK IN THE WINDS
TUESDAY NIGHT INTO EARLY WEDNESDAY AS GRADIENT TIGHTENS AHEAD OF
COLD FRONTAL BOUNDARY MOVING INTO NORTHERN SECTIONS BEFORE
DISSIPATING. OTHERWISE...SHOULD SEE SOUTHWEST WINDS OF 15 KNOTS OR
LESS AND SEAS GENERALLY 2 TO 4 FEET THROUGHOUT THE PERIOD. LATEST
WAVEWATCH 4 AND LOCAL SWAN IN DECENT AGREEMENT ON WAVEHEIGHTS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
AMZ150-152-154.
&&
$$
SYNOPSIS...TL
NEAR TERM...RSB
SHORT TERM...TL
LONG TERM...CTC
AVIATION...CTC/HSA/TL
MARINE...CTC/HSA/TL
AREA FORECAST DISCUSSION
NWS TULSA OK
1230 PM CDT SUN AUG 12 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SCATTERED SHOWERS WILL CONTINUE WITHIN MID CLOUD DECK AHEAD OF
APPROACHING FRONTAL BOUNDARY. ISOLATED STORMS LATE AFTERNOON WILL
BE MENTIONED ACROSS OK SITES...WITH A LATE EVENING / NIGHT
MENTION FURTHER EAST AS FRONT SLOWS. CLEARING SKIES AND NORTHERLY
WINDS WILL FOLLOW FRONT.
&&
.PREV DISCUSSION... /ISSUED 1129 AM CDT SUN AUG 12 2012/
..UPDATE...
DISCUSSION...
COLD FRONT / SFC TROUGH CURRENTLY EXTENDS FROM NORTH CENTRAL OK
INTO SOUTHWEST OK WITH EXTENSIVE MID CLOUD PREVAILING AHEAD OF THE
BOUNDARY. SATELLITE SHOWS CLEARING RECENTLY UNDERWAY AHEAD OF THE
BOUNDARY...WHERE BOTH NAM AND RAP DATA HAVE TEMPS SOARING THIS
AFTERNOON. WHILE CURRENT TEMP TRENDS ARE BEHIND PACE...WILL
MAINTAIN FORECAST HIGHS AS A QUICK WARM UP THIS AFTERNOON IS
LIKELY. REGARDING AFTERNOON / EVENING CONVECTION...STRONGLY VEERED
FLOW WILL KEEP THE DEEPER MOISTURE CURRENTLY OVER EAST TEXAS
PUSHED TO OUR SE. THIS WILL DELAY...AND POSSIBLE HINDER...DEEP
CONVECTION THIS AFTERNOON. HOWEVER GIVEN THE APPROACHING WAVE
ALOFT AND EXPECTED SFC TEMPS...ADJUSTED FORECAST SOUNDINGS REMOVE
AFTERNOON INHIBITION WITHIN A MODERATELY SHEARED ENVIRONMENT. ANY
STORMS THAT DO FORM WILL BE HIGH BASED AND CAPABLE OF STRONG WINDS
AND HAIL. GIVEN LATEST LOCAL WRF RUNS ALONG WITH HRRR DATA WILL
KEEP THE POPS LOW GIVEN EXPECTATIONS OF IMITED STORM COVERAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 102 68 96 65 / 20 20 10 10
FSM 95 72 99 68 / 20 30 10 10
MLC 99 71 99 65 / 30 30 10 10
BVO 103 61 94 61 / 20 20 0 10
FYV 92 65 91 60 / 20 30 10 10
BYV 91 67 90 61 / 30 30 10 10
MKO 98 68 98 63 / 20 30 10 10
MIO 98 65 90 63 / 30 20 10 10
F10 100 69 98 65 / 30 20 10 10
HHW 98 73 100 68 / 30 40 20 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
1129 AM CDT SUN AUG 12 2012
...UPDATE...
.DISCUSSION...
COLD FRONT / SFC TROUGH CURRENTLY EXTENDS FROM NORTH CENTRAL OK
INTO SOUTHWEST OK WITH EXTENSIVE MID CLOUD PREVAILING AHEAD OF THE
BOUNDARY. SATELLITE SHOWS CLEARING RECENTLY UNDERWAY AHEAD OF THE
BOUNDARY...WHERE BOTH NAM AND RAP DATA HAVE TEMPS SOARING THIS
AFTERNOON. WHILE CURRENT TEMP TRENDS ARE BEHIND PACE...WILL
MAINTAIN FORECAST HIGHS AS A QUICK WARM UP THIS AFTERNOON IS
LIKELY. REGARDING AFTERNOON / EVENING CONVECTION...STRONGLY VEERED
FLOW WILL KEEP THE DEEPER MOISTURE CURRENTLY OVER EAST TEXAS
PUSHED TO OUR SE. THIS WILL DELAY...AND POSSIBLE HINDER...DEEP
CONVECTION THIS AFTERNOON. HOWEVER GIVEN THE APPROACHING WAVE
ALOFT AND EXPECTED SFC TEMPS...ADJUSTED FORECAST SOUNDINGS REMOVE
AFTERNOON INHIBITION WITHIN A MODERATELY SHEARED ENVIRONMENT. ANY
STORMS THAT DO FORM WILL BE HIGH BASED AND CAPABLE OF STRONG WINDS
AND HAIL. GIVEN LATEST LOCAL WRF RUNS ALONG WITH HRRR DATA WILL
KEEP THE POPS LOW GIVEN EXPECTATIONS OF IMITED STORM COVERAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 102 68 96 65 / 20 20 10 10
FSM 95 72 99 68 / 20 30 10 10
MLC 99 71 99 65 / 30 30 10 10
BVO 103 61 94 61 / 20 20 0 10
FYV 92 65 91 60 / 20 30 10 10
BYV 91 67 90 61 / 30 30 10 10
MKO 98 68 98 63 / 20 30 10 10
MIO 98 65 90 63 / 30 20 10 10
F10 100 69 98 65 / 30 20 10 10
HHW 98 73 100 68 / 30 40 20 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
158 AM EDT SUN AUG 12 2012
.SYNOPSIS...
AN UNSEASONABLY STRONG UPPER LEVEL LOW OVER THE LOWER GREAT LAKES
WILL SLOWLY LIFT NORTHWARD THROUGH SUNDAY. A RIDGE OF HIGH
PRESSURE WILL SLIDE EAST ACROSS THE COMMONWEALTH ON MONDAY
PROVIDING SPLENDID MID-SUMMER WEATHER. THE NEXT CHANCE FOR MORE
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL COME TUESDAY AFTERNOON
AND EVENING AS A COLD FRONT MOVES THROUGH THE OHIO VALLEY AND
ACROSS THE STATE. DRY WEATHER WILL RETURN FOR WEDNESDAY AND
THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SATELLITE LOOP CONTINUES TO SHOW A VERY COOL SEASON-LOOKING LOW
SPINNING OVER THE LOWER LAKES. MOST OF THE THICKEST LOW CLOUDS
HAVE STAYED STACKED OVER WESTERN PA WHERE TEMPS HAVE STAYED IN THE
CHILLY 60S FOR THE MOST PART.
LATEST LOOP SHOWS A SURGE IN MID/HIGH CLOUDS UP OVER SERN PA
INDICATING A WEAK WAVE SLIDING NORTH ALONG THE FRONT. THE RESPONSE
TO THIS HAS BEEN A SMALL BUT PERSISTENT AREA OF SHOWERS AND STORMS
THAT JUST CLIPPED ERN LANCASTER CTY.
LATEST HRRR AND NAM BRING THE SHOWERS TO AN END AROUND OR SHORTLY
AFTER MIDNIGHT...WITH DRIER AIR FINALLY FILTERING IN LATER
TONIGHT.
AS FOR THE REMAINDER OF THE REGION...THE THICKER CLOUDS WILL
DOMINATE WESTERN AREAS WITH SOME SCATTERED LIGHT SHOWERS OR
SPRINKLES. CAN`T SEE MUCH WORSE THAN SLIGHT CHANCE OR LOW CHANCE
POPS AS THE UPPER SYSTEM SPINS AWAY INTO THE OVERNIGHT.
IT WILL BE VERY COMFORTABLE FOR SLEEPING OVER MOST OF THE AREA AS
DRY AIR DOMINATES ALL BUT THE FAR SERN ZONES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
THE UPPER LOW WILL BE SLOWLY LIFTING NNE TOWARD WRN QUEBEC CANADA.
HOWEVER...THE SOUTHWARD TRAILING...MID-LEVEL THERMAL TROUGH WILL BE
RIGHT OVER THE CWA DURING THE PEAK HEATING OF THE LATE
MORNING/AFTERNOON HOURS. MORNING SUNSHINE SHOULD QUICKLY SELF
DESTRUCT INTO WIDESPREAD BKN STRATO CU ACROSS THE NRN TWO THIRDS OF
THE CWA. ISOLATED SHOWERS WILL DEVELOP ACROSS THE NRN MTNS DURING
THE MIDDAY/AFTERNOON. ANY PRECIP ACROSS THE CENTRAL MTNS AND LAURELS
SHOULD BE LIMITED TO SCATTERED SPRINKLES.
MAX TEMPS ON SUNDAY WILL RETURN TO NEAR NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE MID RANGE MODELS SEEM TO ALL BE IN AGREEMENT THAT THE TROUGH
WILL CONTINUE TO LIFT NORTHEASTWARD THROUGH SUNDAY NIGHT AND
MONDAY MORNING. WITH DRY AIR ADVECTION AND LOW PWATS...EXPECT
CLEARING WITH NO PRECIPITATION IN THE FORECAST THROUGH MONDAY. A
TROUGH WILL BEGIN ITS TREK THROUGH THE MIDWEST TUESDAY...BRINGING
A DECENT FRONT THROUGH. THE MODELS VARY SLIGHTLY ON THE
TIMING...AND CURRENT GEFS HAS NEUTRAL PWATS. THE SYSTEM WILL
PROGRESS THROUGH TUESDAY NIGHT INTO WEDNESDAY AND DEPENDING ON THE
MOISTURE ADVECTION...SCATTERED SHOWERS ARE POSSIBLE. AS SUCH HAVE
INCREASED POPS TUESDAY AFTERNOON INTO WEDNESDAY MORNING. THE
SYSTEM SHOULD LIFT OUT...THOUGH THIS IS WHEN THE MODELS SOLUTIONS BEGIN
TO DIVERGE. THE QUESTION SEEMS TO BE THE STRENGTH OF THE RIDGE
THAT WILL BUILD OVER EASTERN CANADA ON THURSDAY. THE GFS HAS A
WEAKER RIDGE WITH A TROUGH MOVING THROUGH CENTRAL CANADA WITH NO
TILT. THE EC HAS A STRONG RIDGE WAND A TROUGH THAT IS POSITIONED FURTHER
NORTH WITH A MORE NEGATIVE TILT. BOTH DRAG A FRONT THROUGH THE
REGION...WITH CONSIDERABLY MORE MOISTURE...FRIDAY INTO SATURDAY.
MODEL TEMPERATURES ARE TRENDING DOWNWARD...WITH SEVERAL DAYS MAX TEMPS
BELOW NORMAL. MIN TEMPS ARE TRENDING SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS CONTINUE OVER MOST OF CENTRAL PENNSYLVANIA
AS OF EARLY THIS MORNING...THE EXCEPTION BEING ACROSS THE NW
MOUNTAINS /KBFD/ WHERE MVFR TO IFR CIGS ARE OCCURRING.
STILL EXPECTING SOME MVFR FOG CONDITIONS OVERNIGHT AT MOST
AIRFIELDS... EXCEPT MAYBE ACROSS THE FAR SE WHERE THE MENTION OF
RESTRICTED CONDITIONS HAVE BEEN LEFT OUT OF TAFS AT THE PRESENT
TIME. THINKING IS THAT THICKER CLOUDS THERE WILL KEEP TEMPS FROM
FALLING TO THE DEWPOINT.
AFTER MORNING FOG AND SOME STRATUS...MOST AREAS WILL RETURN TO
VFR CONDITIONS DURING THE MORNING. EXCEPTION WILL BE AT KBFD WHERE
LINGERING COLD POOL/UPPER LOW WILL KEEP CLOUDS AND THE BEST CHANCE
OF SHOWERS WELL PAST NOON.
CHANCE OF SOME AREAS MVFR FOG AGAIN SUNDAY NIGHT...THEN VFR REST
OF THE DAY ON MONDAY.
OUTLOOK...
TUE...MAINLY VFR WITH SCT SHRA/TSRA.
WED...MAINLY VFR. ISOLD SHRA POSSIBLE.
THU...PATCHY VALLEY FOG AND MVFR VSBYS EARLY...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...CERU/STEINBUGL
AVIATION...JUNG/GARTNER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
916 PM EDT MON AUG 13 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE NORTHWEST TONIGHT AS
HIGH PRESSURE MOVES OFF THE ATLANTIC COAST. THIS FRONT WILL CROSS
OUR REGION LATE TUESDAY FOLLOWED BY HIGH PRESSURE WEDNESDAY AND
THURSDAY. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE AREA LATE IN
THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 915 PM...LATEST RADAR IMAGES INDICATE THAT RAINFALL ACROSS THE
MTNS WAS RAPIDLY DISSIPATING. I WILL UPDATE THE FORECAST TO CUT BACK
POPS AND ADJUST CLOUD COVER. A RECENT INCREASE IN MID MISSISSIPPI
RIVER VALLEY CONVECTION IS EVIDENT ON LATEST SATELLITE IMAGES.
CORFIDI VECTORS INDICATE THAT THE CONVECTION WILL FAVOR A E-SE TRACK
ACROSS THE DEEP SOUTH AND TN...POSSIBLY TURNING DUE EAST ACROSS
EASTERN TN AND NRN GA. BASED ON LATEST MODEL RUNS AND SATELLITE
TRENDS...IT APPEARS SAFE TO KEEP THE FORECAST DRY THROUGH MOST OF
THE NIGHT...WITH POPS INCREASING TO CHC DURING THE PRE DAWN HOURS
ACROSS THE MTNS.
AS OF 745 PM...I WILL UPDATE THE FORECAST TO ADJUST POPS ACROSS THE
NC MTNS AND UPPER SAVANNAH RIVER VALLEY THIS EVENING. LATEST RADAR
AND SATELLITE IMAGES INDICATE THAT THE MCS IS STEADILY WEAKENING. I
WILL EXPECT THAT ISO SHRA WILL REACH AS FAR EAST AS THE GSP AREA
BEFORE DISSIPATING. I WILL ALSO SIGNIFICANTLY DECREASE THE THUNDER
MENTION WITH THIS UPDATE. IN ADDITION...I WILL INCREASE SKY COVER
AND ADJUST TEMPS/DWPT TO OBS.
AS OF 545 PM...RECENT RADAR IMAGES INDICATE A WEAKENING LINE OF
SHOWERS AND EMBEDDED TSRA ACROSS EASTERN TN AND NRN GA. RECENT IR
SATELLITE IMAGES INDICATE THAT CLOUD TOP TEMPERATURES ARE WARMING
STEADILY WITH CLOUD TO GROUND LIGHTNING COUNTS DECREASING
SIGNIFICANTLY. HOWEVER...THE BAND SHOULD SURVIVE TO PRODUCE
MEASURABLE RAINFALL ACROSS THE WESTERN NC MTNS AND NE GA THROUGH
EARLY THIS EVENING. BASED ON RADAR AND SATELLITE TRENDS AND THE
CURRENT TEMPERATURE PROFILES...IT APPEARS THAT RAINFALL WILL
DISSIPATE RAPIDLY EAST OF THE SAVANNAH AND FRENCH BROAD RIVER
VALLEYS.
AS OF 430 PM...A BROAD NORTH TO SOUTH ORIENTED LINE OF SHOWERS AND
THUNDERSTORMS WAS LOCATED ALONG THE NORTHERN BORDER BETWEEN AL AND
GA. THE LINE IS PUSHING EAST INTO WEAKLY UNSTABLE AIR...WITH THE
LATEST CAPE ANALYSIS INDICATING ONLY 100 J/KG OF CAPE OVER THE
WESTERN NC MTNS. BASED ON THE RADAR TRENDS...LIGHTNING RATES...AND
RATE OF WARMING CLOUD TOP TEMPERATURES...A BAND OF FADING CONVECTION
WILL REACH THE WESTERN NC MTNS BEFORE TOTALLY DISSIPATING DURING THE
LATE EVENING. I WILL INCREASE POPS TO CHC ACROSS THE WESTERN NC MTNS
AND HIGHLIGHT GENERAL THUNDERSTORMS IN THE HWO. I WILL ALSO UPDATE
THE FORECAST TO ALIGN TEMPS AND DWPTS WITH OBSERVATIONS.
AS OF 145 PM...THE MAIN THING OF CONCERN FOR THIS UPDATE IS A LINE
OF CONVECTION CROSSING CENTRAL TN AND AL ATTM. THE MODELS DO NOT
SEEM TO BE HANDLING THIS VERY WELL. ATTM...IT STILL LOOKED LIKE THE
LINE WILL LOSE STEAM AS IT ENCOUNTERS STABLE AIR OVER ERN TN AND GA.
WITH THAT SAID...THE LATEST RAP BRINGS INSTBY WITH THE LINE (AS IT
IS NOT MOVING VERY FAST)...SUCH THAT THE SW NC MTNS DO DEVELOP ABOUT
1000-1500 J/KG OF CAPE BY 23Z AS THE LINE ARRIVES. THE CONVECTION
WILL HAVE THE ASSOCIATED MCV TO HELP WITH FORCING AS WELL. SO
ANOTHER UPDATE MAY BE NEEDED SHORTLY TO BUMP UP POP THERE. FOR
SURE...THE MOISTURE WILL SPREAD IN THIS EVENING/OVERNIGHT BRINGING
MAINLY MID AND HIGH CLOUDS. SOME SHWRS MAY SURVIVE INTO THE NC MTNS
THRU DAYBREAK. TEMPS ARE STILL FCST TO DROP TO NORMAL OR EVEN A
CATEGORY BELOW (THO THOSE MAY BE TOO COOL GIVEN EXPECTED CLOUD
COVER).
TUESDAY...A SHORTWAVE TROF WILL ROUND THE BASE OF THE LONGWAVE TROF
AXIS INVOF THE OH/TN VLYS. MEANWHILE...AN ASSOCIATED SFC LOW WILL
TRACK FROM THE MID MS VLY TO AROUND LAKE ERIE BY TUESDAY EVENING.
THE LOW PRES SYSTEM WILL PUSH A COLD FRONT ACRS THE OH/TN VLYS ON
TUESDAY...WITH PRE-FRONTAL BAND OF MOISTURE CROSSING THE CWFA.
GUIDANCE IN GOOD AGREEMENT OF HIGH-END CHC POPS FOR MOST OF THE AREA
WITH DECENT INSTBY AND NOMINAL BULK SHEAR. LLVL CONVERGENCE AND UPR
SUPPORT DO NOT LOOK THAT IMPRESSIVE. SO NOT EXPECTING TOO MUCH
ORGANIZATION. HOWEVER...A FEW SEVERE STORM CLUSTERS WILL BE POSSIBLE
TUESDAY AFTN. TEMPS WILL BE ONE TO TWO CATEGORIES BELOW NORMAL UNDER
MOSTLY CLOUDY SKIES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 245 PM MONDAY...A SHORT WAVE SWINGS ACROSS THE AREA TUE NITE
THEN EAST ON WED...LEAVING NEARLY ZONAL FLOW IN ITS WAKE FOR THU. AT
THE SFC...A COLD FRONT MOVES THRU WITH THE WAVE TUE NITE THEN EAST
OF THE AREA WED AS WELL. HIGH PRESSURE BUILDS IN FOR THU. EXPECT SCT
CONVECTION TO BE ONGOING TUE EVENING WHICH THEN DISSIPATES OVERNIGHT
WITH LOSS OF INSTABILITY. HOWEVER...ISOLATED SHRA COULD LINGER OVER
THE EAST NEAR THE FRONT AND OVER THE MTNS IN THE DEVELOPING WLY FLOW
AND LINGERING LOW LEVEL MOISTURE. ATMOS BECOMES CAPPED WED WITH
WARMER MID LEVEL TEMPS AND DIMINISHING LOW LEVEL MOISTURE IN THE
DEVELOPING WLY FLOW. TEMPS NEAR NORMAL TUE NITE AND WED. ATMOS
REMAINS CAPPED THU AS RELATIVELY WARM MID LEVEL TEMPS CONTINUE. LOW
LEVEL MOISTURE WILL BE LIMITED AS WELL. HOWEVER...ENUF H85 MOISTURE
WILL BE AROUND FOR A DECENT CU FIELD TO DEVELOP DURING THE
AFTERNOON. THEREFORE...HAVE A CONTINUED DRY FCST WITH LOWS FALLING A
LITTLE BELOW NORMAL BUT HIGHS REMAINING NEARLY STEADY AROUND NORMAL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EDT MONDAY...THE LATEST MEDIUM RANGE MODELS INDICATE
THAT A WEAK RIDGE OF HIGH OVER OUR AREA MOVES OFF TO THE EAST ON
LATE THURSDAY AS A COLD FRONT AND ASSOCIATED UPPER TROUGH OVER THE
GREAT LAKES REGION DIGS SOUTH INTO TN/OH. THE FRONT IS EXPECTED TO
SLIP FURTHER SOUTH INTO THE APPALACHIANS BY FRIDAY AND CROSSES OUR
CWA ON SATURDAY. WITH DEEPENING MOISTURE...MODERATE INSTABILITY
AND UPPER LEVEL DIVERGENCE...WILL INCREASE POPS INTO THE 30-40
PERCENT RANGE FRI/SAT. SOME THUNDERSTORMS COULD BE SEVERE ON
SATURDAY MAINLY OVER THE BLUE RIDGE AND NORTH CAROLINA PIEDMONT AS
MODEL SOUNDINGS SHOW FAIRLY STRONG 0-6KM BULK WIND SHEAR MAGNITUDE
OF +30KT AND MODERATE CAPE VALUES THERE. AS THE FRONT MOVES OFF TO
THE EAST...HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST SUNDAY AND
REMAIN THROUGH MONDAY. TEMPERATURES WILL REMAIN 3 TO 5 DEGREES BELOW
NORMAL WITH AFTERNOON HIGHS IN THE LOW TO MID 80S DURING THE PERIOD.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
AT KCLT...MID LEVEL DEBRIS CLOUDS WILL INCREASE OVER THE TERMINAL
THROUGH MOST OF THIS EVENING. BKN MID LEVEL CLOUDS WILL LIKELY
LINGER ACROSS THE TERMINAL THROUGH TONIGHT. THE INCREASING SKY COVER
AND PERSISTENT LIGHT SW WIND SHOULD FAVOR VFR CONDITIONS OVERNIGHT.
AS A COLD FRONT PUSHES INTO EAST TN...SOUTHWEST WINDS WILL LIKELY
STRENGTHEN THROUGH THE DAYLIGHT HOURS TOMORROW...WITH GUSTS INTO THE
TEENS DURING THE AFTERNOON. A BAND OF PRE FRONTAL SHRA/TSRA MAY
SWEEP ACROSS THE REGION DURING THE AFTERNOON...I WILL INCLUDE A
PROB30 BETWEEN 19Z TO 22Z.
ELSEWHERE...THIS EVENING...A DISSIPATING MCS MAY YIELD -RA AT KAND
AND KAVL AND VCSH AT KGMU AND KGSP THIS EVENING. OTHERWISE...MID
LEVEL CLOUDS WILL INCREASE AND THICKEN ACROSS THE WESTERN CAROLINAS
THIS EVENING AND LINGER THROUGH MOST OF THE NIGHT. THE INCREASING
SKY COVER AND PERSISTENT LIGHT SW WIND SHOULD FAVOR VFR CONDITIONS
OVERNIGHT FOR MOST WESTERN NC TERMINALS. I WILL INCLUDE MVFR FOG AT
KHKY AROUND SUNRISE. AS A COLD FRONT PUSHES INTO EAST TN...SOUTHWEST
WINDS WILL LIKELY STRENGTHEN THROUGH THE DAYLIGHT HOURS
TOMORROW...WITH GUSTS INTO THE TEENS DURING THE AFTERNOON AT KGMU
AND KGSP. A BAND OF PRE FRONTAL SHRA/TSRA MAY SWEEP ACROSS THE MTNS
AROUND MID DAY AND EAST DURING THE AFTERNOON...I WILL INCLUDE A
PROB30 FOR TSRA.
OUTLOOK...A SLOW MOVING COLD FRONT IS EXPECTED TO CROSS THE SOUTHERN
APPALACHIAN REGION TUESDAY EVENING THROUGH TUESDAY NIGHT...BRINGING A CHC
FOR SHRA/TSRA. THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER
THE REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...NED
SHORT TERM...RWH
LONG TERM...JOH
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
743 PM EDT MON AUG 13 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE NORTHWEST TONIGHT AS
HIGH PRESSURE MOVES OFF THE ATLANTIC COAST. THIS FRONT WILL CROSS
OUR REGION LATE TUESDAY FOLLOWED BY HIGH PRESSURE WEDNESDAY AND
THURSDAY. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE AREA LATE IN
THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 745 PM...I WILL UPDATE THE FORECAST TO ADJUST POPS ACROSS THE
NC MTNS AND UPPER SAVANNAH RIVER VALLEY THIS EVENING. LATEST RADAR
AND SATELLITE IMAGES INDICATE THAT THE MCS IS STEADILY WEAKENING. I
WILL EXPECT THAT ISO SHRA WILL REACH AS FAR EAST AS THE GSP AREA
BEFORE DISSIPATING. I WILL ALSO SIGNIFICANTLY DECREASE THE THUNDER
MENTION WITH THIS UPDATE. IN ADDITION...I WILL INCREASE SKY COVER
AND ADJUST TEMPS/DWPT TO OBS.
AS OF 545 PM...RECENT RADAR IMAGES INDICATE A WEAKENING LINE OF
SHOWERS AND EMBEDDED TSRA ACROSS EASTERN TN AND NRN GA. RECENT IR
SATELLITE IMAGES INDICATE THAT CLOUD TOP TEMPERATURES ARE WARMING
STEADILY WITH CLOUD TO GROUND LIGHTNING COUNTS DECREASING
SIGNIFICANTLY. HOWEVER...THE BAND SHOULD SURVIVE TO PRODUCE
MEASURABLE RAINFALL ACROSS THE WESTERN NC MTNS AND NE GA THROUGH
EARLY THIS EVENING. BASED ON RADAR AND SATELLITE TRENDS AND THE
CURRENT TEMPERATURE PROFILES...IT APPEARS THAT RAINFALL WILL
DISSIPATE RAPIDLY EAST OF THE SAVANNAH AND FRENCH BROAD RIVER
VALLEYS.
AS OF 430 PM...A BROAD NORTH TO SOUTH ORIENTED LINE OF SHOWERS AND
THUNDERSTORMS WAS LOCATED ALONG THE NORTHERN BORDER BETWEEN AL AND
GA. THE LINE IS PUSHING EAST INTO WEAKLY UNSTABLE AIR...WITH THE
LATEST CAPE ANALYSIS INDICATING ONLY 100 J/KG OF CAPE OVER THE
WESTERN NC MTNS. BASED ON THE RADAR TRENDS...LIGHTNING RATES...AND
RATE OF WARMING CLOUD TOP TEMPERATURES...A BAND OF FADING CONVECTION
WILL REACH THE WESTERN NC MTNS BEFORE TOTALLY DISSIPATING DURING THE
LATE EVENING. I WILL INCREASE POPS TO CHC ACROSS THE WESTERN NC MTNS
AND HIGHLIGHT GENERAL THUNDERSTORMS IN THE HWO. I WILL ALSO UPDATE
THE FORECAST TO ALIGN TEMPS AND DWPTS WITH OBSERVATIONS.
AS OF 145 PM...THE MAIN THING OF CONCERN FOR THIS UPDATE IS A LINE
OF CONVECTION CROSSING CENTRAL TN AND AL ATTM. THE MODELS DO NOT
SEEM TO BE HANDLING THIS VERY WELL. ATTM...IT STILL LOOKED LIKE THE
LINE WILL LOSE STEAM AS IT ENCOUNTERS STABLE AIR OVER ERN TN AND GA.
WITH THAT SAID...THE LATEST RAP BRINGS INSTBY WITH THE LINE (AS IT
IS NOT MOVING VERY FAST)...SUCH THAT THE SW NC MTNS DO DEVELOP ABOUT
1000-1500 J/KG OF CAPE BY 23Z AS THE LINE ARRIVES. THE CONVECTION
WILL HAVE THE ASSOCIATED MCV TO HELP WITH FORCING AS WELL. SO
ANOTHER UPDATE MAY BE NEEDED SHORTLY TO BUMP UP POP THERE. FOR
SURE...THE MOISTURE WILL SPREAD IN THIS EVENING/OVERNIGHT BRINGING
MAINLY MID AND HIGH CLOUDS. SOME SHWRS MAY SURVIVE INTO THE NC MTNS
THRU DAYBREAK. TEMPS ARE STILL FCST TO DROP TO NORMAL OR EVEN A
CATEGORY BELOW (THO THOSE MAY BE TOO COOL GIVEN EXPECTED CLOUD
COVER).
TUESDAY...A SHORTWAVE TROF WILL ROUND THE BASE OF THE LONGWAVE TROF
AXIS INVOF THE OH/TN VLYS. MEANWHILE...AN ASSOCIATED SFC LOW WILL
TRACK FROM THE MID MS VLY TO AROUND LAKE ERIE BY TUESDAY EVENING.
THE LOW PRES SYSTEM WILL PUSH A COLD FRONT ACRS THE OH/TN VLYS ON
TUESDAY...WITH PRE-FRONTAL BAND OF MOISTURE CROSSING THE CWFA.
GUIDANCE IN GOOD AGREEMENT OF HIGH-END CHC POPS FOR MOST OF THE AREA
WITH DECENT INSTBY AND NOMINAL BULK SHEAR. LLVL CONVERGENCE AND UPR
SUPPORT DO NOT LOOK THAT IMPRESSIVE. SO NOT EXPECTING TOO MUCH
ORGANIZATION. HOWEVER...A FEW SEVERE STORM CLUSTERS WILL BE POSSIBLE
TUESDAY AFTN. TEMPS WILL BE ONE TO TWO CATEGORIES BELOW NORMAL UNDER
MOSTLY CLOUDY SKIES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 245 PM MONDAY...A SHORT WAVE SWINGS ACROSS THE AREA TUE NITE
THEN EAST ON WED...LEAVING NEARLY ZONAL FLOW IN ITS WAKE FOR THU. AT
THE SFC...A COLD FRONT MOVES THRU WITH THE WAVE TUE NITE THEN EAST
OF THE AREA WED AS WELL. HIGH PRESSURE BUILDS IN FOR THU. EXPECT SCT
CONVECTION TO BE ONGOING TUE EVENING WHICH THEN DISSIPATES OVERNIGHT
WITH LOSS OF INSTABILITY. HOWEVER...ISOLATED SHRA COULD LINGER OVER
THE EAST NEAR THE FRONT AND OVER THE MTNS IN THE DEVELOPING WLY FLOW
AND LINGERING LOW LEVEL MOISTURE. ATMOS BECOMES CAPPED WED WITH
WARMER MID LEVEL TEMPS AND DIMINISHING LOW LEVEL MOISTURE IN THE
DEVELOPING WLY FLOW. TEMPS NEAR NORMAL TUE NITE AND WED. ATMOS
REMAINS CAPPED THU AS RELATIVELY WARM MID LEVEL TEMPS CONTINUE. LOW
LEVEL MOISTURE WILL BE LIMITED AS WELL. HOWEVER...ENUF H85 MOISTURE
WILL BE AROUND FOR A DECENT CU FIELD TO DEVELOP DURING THE
AFTERNOON. THEREFORE...HAVE A CONTINUED DRY FCST WITH LOWS FALLING A
LITTLE BELOW NORMAL BUT HIGHS REMAINING NEARLY STEADY AROUND NORMAL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EDT MONDAY...THE LATEST MEDIUM RANGE MODELS INDICATE
THAT A WEAK RIDGE OF HIGH OVER OUR AREA MOVES OFF TO THE EAST ON
LATE THURSDAY AS A COLD FRONT AND ASSOCIATED UPPER TROUGH OVER THE
GREAT LAKES REGION DIGS SOUTH INTO TN/OH. THE FRONT IS EXPECTED TO
SLIP FURTHER SOUTH INTO THE APPALACHIANS BY FRIDAY AND CROSSES OUR
CWA ON SATURDAY. WITH DEEPENING MOISTURE...MODERATE INSTABILITY
AND UPPER LEVEL DIVERGENCE...WILL INCREASE POPS INTO THE 30-40
PERCENT RANGE FRI/SAT. SOME THUNDERSTORMS COULD BE SEVERE ON
SATURDAY MAINLY OVER THE BLUE RIDGE AND NORTH CAROLINA PIEDMONT AS
MODEL SOUNDINGS SHOW FAIRLY STRONG 0-6KM BULK WIND SHEAR MAGNITUDE
OF +30KT AND MODERATE CAPE VALUES THERE. AS THE FRONT MOVES OFF TO
THE EAST...HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST SUNDAY AND
REMAIN THROUGH MONDAY. TEMPERATURES WILL REMAIN 3 TO 5 DEGREES BELOW
NORMAL WITH AFTERNOON HIGHS IN THE LOW TO MID 80S DURING THE PERIOD.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AT KCLT...MID LEVEL DEBRIS CLOUDS WILL INCREASE OVER THE TERMINAL
THROUGH MOST OF THIS EVENING. BKN MID LEVEL CLOUDS WILL LIKELY
LINGER ACROSS THE TERMINAL THROUGH TONIGHT. THE INCREASING SKY COVER
AND PERSISTENT LIGHT SW WIND SHOULD FAVOR VFR CONDITIONS OVERNIGHT.
AS A COLD FRONT PUSHES INTO EAST TN...SOUTHWEST WINDS WILL LIKELY
STRENGTHEN THROUGH THE DAYLIGHT HOURS TOMORROW...WITH GUSTS INTO THE
TEENS DURING THE AFTERNOON. A BAND OF PRE FRONTAL SHRA/TSRA MAY
SWEEP ACROSS THE REGION DURING THE AFTERNOON...I WILL INCLUDE A
PROB30 BETWEEN 19Z TO 22Z.
ELSEWHERE...THIS EVENING...A DISSIPATING MCS MAY YIELD -RA AT KAND
AND KAVL AND VCSH AT KGMU AND KGSP THIS EVENING. OTHERWISE...MID
LEVEL CLOUDS WILL INCREASE AND THICKEN ACROSS THE WESTERN CAROLINAS
THIS EVENING AND LINGER THROUGH MOST OF THE NIGHT. THE INCREASING
SKY COVER AND PERSISTENT LIGHT SW WIND SHOULD FAVOR VFR CONDITIONS
OVERNIGHT FOR MOST WESTERN NC TERMINALS. I WILL INCLUDE MVFR FOG AT
KHKY AROUND SUNRISE. AS A COLD FRONT PUSHES INTO EAST TN...SOUTHWEST
WINDS WILL LIKELY STRENGTHEN THROUGH THE DAYLIGHT HOURS
TOMORROW...WITH GUSTS INTO THE TEENS DURING THE AFTERNOON AT KGMU
AND KGSP. A BAND OF PRE FRONTAL SHRA/TSRA MAY SWEEP ACROSS THE MTNS
AROUND MID DAY AND EAST DURING THE AFTERNOON...I WILL INCLUDE A
PROB30 FOR TSRA.
OUTLOOK...A SLOW MOVING COLD FRONT IS EXPECTED TO CROSS THE SOUTHERN
APPALACHIAN REGION TUESDAY EVENING THROUGH TUESDAY NIGHT...BRINGING A CHC
FOR SHRA/TSRA. THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER
THE REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...NED
SHORT TERM...RWH
LONG TERM...JOH
AVIATION...NED
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
650 PM CDT MON AUG 13 2012
.DISCUSSION...
UPDATED FOR 00Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 226 PM CDT MON AUG 13 2012/
MORNING CONVECTION HAS MOVED EAST OF THE MIDSOUTH AS EXPECTED
WITH PARTIAL SUNSHINE SPREADING OVER THE AREA FROM THE WEST.
MEANWHILE...A COLD FRONT IS PUSHING INTO NORTHEAST ARKANSAS AND
STRETCHES SOUTHWESTWARD INTO NORTHEAST TX. THE FRONT HAS MOVED
THROUGH WALNUT RIDGE ARKANSAS AND IS APPROACHING JONESBORO.
STILL THINK THERE IS A CHANCE OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON INTO THIS EVENING ALONG AND AHEAD OF THE COLD
FRONT...ALTHOUGH THE SITUATION IS NOT CLEAR CUT. WATER VAPOR IMAGERY
INDICATES THE MAIN UPPER LEVEL TROUGH IS MOVING EAST OF THE MIDSOUTH
WITH UPPER LEVEL SUPPORT NOW LIMITED ACROSS OUR FORECAST AREA. WATER
VAPOR IMAGERY IS ALSO SHOWING VERY DRY AIR ALOFT MOVING INTO OUR
FORECAST AREA. HOWEVER...VERY WARM AND UNSTABLE AIR IS PUSHING INTO
THE AREA AHEAD OF THE FRONT ON SOUTHWEST SURFACE WINDS. TEMPERATURES
IN NORTHEAST AND EAST CENTRAL AR ARE MOVING INTO THE LOWER 90S AND
SURFACE BASED CAPES HAVE INCREASED TO BETWEEN 2000 AND 2500 J/KG AND
LIFTED INDICES HAVE DECREASED TO ABOUT MINUS 6.
LATEST HIGH RESOLUTION RAPID REFRESH (HRRR) MODEL INDICATES THAT
SCATTERED SHOWERS AND THUNDERSTORMS WILL BEGIN TO FORM ALONG THE
COLD FRONT BY 3 OR 4 PM...THEN BECOME A LITTLE BETTER ORGANIZED AS
THE STORMS MOVE EAST OF THE MS RIVER BY LATE AFTERNOON AND EVENING.
MODELS CONTINUE TO INDICATE THE ATMOSPHERE WILL BECOME QUITE
UNSTABLE AHEAD OF THE FRONT WITH SURFACE BASED CAPES INCREASING TO
BETWEEN 32000 AND 4200 J/KG WITH LIFTED INDICES DECREASING TO MINUS
8. ALTHOUGH...THE HRRR MODEL INDICATES THE STORMS WILL STRUGGLE IN
COVERAGE WITH SUCH DRY AIR ALOFT LIMITING THE MOISTURE.
ALTHOUGH...THE DRY AIR ALOFT WILL ENHANCE THE DOWNDRAFT POTENTIAL
WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE IN THE STRONGER STORMS.
LARGE HAIL IS ALSO POSSIBLE.
THE COLD FRONT IS FORECAST NEAR THE MS RIVER BY LATE
AFTERNOON...THEN WILL MOVE SOUTHEASTWARD THROUGH THE MIDSOUTH
TONIGHT. THINK THE SEVERE WEATHER THREAT WILL END BY LATE EVENING.
NOT MUCH CHANGE TO THE EARLIER FORECAST CONCERNING TUESDAY THROUGH
THE WEEKEND. HIGH PRESSURE AND DRIER AIR WILL SPREAD OVER THE
MIDSOUTH TUESDAY INTO WEDNESDAY ALLOWING FOR GOOD DIURNAL SPREADS IN
TEMPERATURES WITH RELATIVELY COOL NIGHTS AND VERY WARM AFTERNOONS.
A WARM FRONT IS FORECAST TO PUSH THROUGH THE MIDSOUTH THURSDAY WITH
VERY UNSTABLE AND MOIST AIR SPREADING BACK OVER THE AREA. THIS WILL
CAUSE A CHANCE OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL
APPROACH FROM THE NORTHWEST THURSDAY NIGHT AND MOVE SLOWLY THROUGH
THE REGION FRIDAY INCREASING THE THREAT OF SHOWERS AND
THUNDERSTORMS. THERE WILL BE A LINGERING CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS EAST CENTRAL ARKANSAS AND NORTH MS SATURDAY BUT
OTHERWISE KEPT WITH A RAINFREE FORECAST FOR THE WEEKEND INTO NEXT
MONDAY. HOWEVER...THERE IS SOME QUESTION HOW FAR THE COLD FRONT WILL
SETTLE SOUTHWARD BECOMING STALLING...SO SOME CHANCE OF SHOWERS AND
THUNDERSTORMS COULD LINGER ACROSS EAST CENTRAL AR AND NORTH MS INTO
SUNDAY.
JCL
&&
.AVIATION...
00Z TAF CYCLE
THE FRONT HAS MOVED THROUGH KJBR AND IS NOW MOVING THROUGH KMEM. TSRAS
HAVE MOVED EAST OF KMEM AND GUSTY NORTH WINDS WILL DIMINISH
QUICKLY. SCT SHRAS AND TSRAS WILL CONTINUE ACROSS EASTERN AREAS OF
THE MIDSOUTH FOR THE NEXT COUPLE OF HOURS AND HAVE CONTINUED VCTS AT
KMKL AND KTUP. VFR CONDS EXPECTED OUTSIDE OF TSRAS OVERNIGHT WITH
SOME FOG POSSIBLE LATER TONIGHT ESPECIALLY AT KMKL AND KTUP.
BECOMING CONCERNED ABOUT THE POSSIBILITY OF LOW CLOUDS EARLY TUESDAY
MORNING. A LARGE DECK OF STRATOCU OVER MO MAY PUSH SE ACROSS THE
AREA LATER TONIGHT. KMKL IS THE MOST LIKELY SPOT TO HAVE MVFR CIGS
AND HAVE ADDED THEM TO THE TAF. THE LOWER CIGS ARE POSSIBLE AT THE
OTHER TAF SITES THOUGH CONFIDENCE IS TOO LOW TO MENTION AT THIS
TIME.
SJM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 70 88 68 93 / 20 0 10 10
MKL 66 86 59 90 / 30 10 10 10
JBR 65 87 62 92 / 10 0 10 10
TUP 71 89 65 91 / 50 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
358 PM CDT SUN AUG 12 2012
.UPDATE...
ISSUING A QUICK UPDATE TO INCLUDE SEVERE THUNDERSTORM WATCH 573 IN
THE PACKAGE. 84
&&
.PREV DISCUSSION... /ISSUED 332 PM CDT SUN AUG 12 2012/
ALTHOUGH THE PRIMARY MODEL GUIDANCE REMAINS IN DISAGREEMENT
REGARDING THE CONVECTIVE POTENTIAL THIS EVENING...SHORT-TERM
MESOSCALE TRENDS ARE SUGGESTING THAT THE WETTER NAM...HI-RES WRF
AND HRRR MODELS ARE ON THE RIGHT TRACK. THE COLD FRONT IS MAKING
STEADY PROGRESS TO THE SOUTH AND AT 3 PM HAS PASSED THROUGH
WICHITA FALLS. HOWEVER OBS AND RADAR INDICATE A REGION OF LOW
LEVEL CONFLUENCE FROM ABILENE TO GRAHAM TO BOWIE. THIS AREA WILL
BE THE FAVORABLE REGION FOR INITIATION...AND CONVECTION LOOKS LIKE
IT WILL INITIATE WELL AHEAD OF THE FRONT. LOCAL OBJECTIVE ANALYSIS
INDICATES AN AXIS OF 1000-2500 J/KG OF CAPE ALONG AND EAST OF A
LINE FROM GAINESVILLE TO MINERAL WELLS TO LAMPASAS...WHILE DEEP
LAYER SHEAR IS NOW RUNNING NEAR 35KT ACROSS MUCH OF THE AREA.
UNLIKE PREVIOUS SUMMERTIME CONVECTIVE EVENTS...IT HAS BEEN A
COUPLE MONTHS SINCE WE HAVE HAD THIS MUCH 0-6KM WIND SHEAR
AVAILABLE. GIVEN THE AVAILABLE INSTABILITY AND SHEAR...BRIEF
SUPERCELLS WILL BE POSSIBLE...BUT THE MOST LIKELY CONVECTIVE MODE
WILL BE LINE SEGMENTS. SURFACE TEMPERATURES ARE 105+ ACROSS THE NW
ZONES AHEAD OF THE FRONT...WHILE DEWPOINTS ARE IN THE MID 50S.
THIS WILL CREATE AN EXTREMELY FAVORABLE ENVIRONMENT FOR
DOWNBURSTS. DAMAGING WINDS WILL BE THE PRIMARY THREAT THIS
EVENING...AND BECAUSE DEEP LAYER SHEAR IS AVAILABLE IT WILL ALSO
ENHANCE THE POTENTIAL FOR LINE SEGMENTS PRODUCING ORGANIZED COLD
POOLS. STRONG OUTFLOW WINDS MAY IMPACT A MUCH WIDER AREA THAN
ACTUAL RAINFALL. WILL ALSO INCLUDE A MENTION OF HAIL IN
HWO..ALTHOUGH HOT TEMPS MAY LIMIT HAIL SIZE. THE SCATTERED
CONVECTION IS EXPECTED TO TRACK NORTHWEST TO SOUTHEAST ACROSS THE
CWA THIS EVENING...AND THE HIGHEST POPS WILL BE PLACED IN A BAND
ACROSS THE CENTRAL CWA.
THE TRUE COLD FRONT WILL LIKELY BE TEMPORARILY HELD UP AS OUTFLOW
FROM CONVECTION OVER OUR AREA RESULTS IN PREDOMINANTLY SOUTHERLY
WINDS ON ITS NORTH SIDE. FRONT PROBABLY WILL NOT REACH THE
METROPLEX UNTIL DAYBREAK AND WILL LIKELY PUSH INTO THE SOUTHERN ZONES
BY AFTERNOON. HIGH TEMPERATURES TOMORROW WILL BE TRICKY...WITH
LOCATIONS ALONG AND SOUTH OF THE FRONT IN THE AFTERNOON BENEFITING
FROM SUBSIDENCE WARMING AND THE TEMPS FORECAST HERE MAY BE TOO
LOW. ON THE OTHER HAND...CURRENT OBSERVATIONS SUGGEST THE FRONT
HAS A STRONG PUSH...AND THEREFORE AM LEANING TOWARD THE GUIDANCE
THAT SHOWS SOME DECENT COLD ADVECTION IN THE LOW LEVELS ACROSS THE
NORTH AND NORTHEAST ZONES. WILL RETAIN A MENTION OF LOW POPS IN
THE SOUTHERN ZONES TOMORROW WHERE THE FRONT SHOULD BECOME ACTIVE
IN THE AFTERNOON HOURS.
NORTHWEST FLOW ALOFT WILL REMAIN IN PLACE THROUGH TUESDAY. MODEL
GUIDANCE IS HAVING SOME TIMING DIFFERENCES WITH RESPECT TO THE
NEXT SHORTWAVE...EITHER AS EARLY AS TUESDAY MORNING AND AS LATE AS
OVERNIGHT TUESDAY. INSTABILITY/SHEAR WILL BE SUFFICIENT FOR A MCS
OR REMNANT MCS OUTFLOW TO AFFECT THE AREA FROM OKLAHOMA DURING
THIS TIME. WILL CONTINUE WITH SLIGHT CHANCE POPS TUESDAY AND TUESDAY
NIGHT. SOUTHERLY WINDS RETURN BY WEDNESDAY AND NORTHWEST FLOW
ALOFT WEAKENS. CONVECTIVE POTENTIAL SHOULD ALSO DIMINISH...WHILE
TEMPS RETURN TO NEAR 100 DEGREES AREA WIDE THROUGH THURSDAY.
IN THE EXTENDED...THE STRONGER COLD FRONT STILL LOOKS ON TRACK.
IT SHOULD ARRIVE FRIDAY MORNING AND GRADUALLY WORK SOUTH THROUGH
THE REGION INTO SATURDAY MORNING. WILL CONTINUE WITH LOW POPS
STARTING THURSDAY NIGHT IN THE NORTH...WITH 30 PERCENT EVERYWHERE
FRIDAY. WILL HAVE POPS GRADUALLY CLEAR OUT FROM NORTH TO SOUTH ON
SATURDAY. THE LINGERING POPS ON SATURDAY ARE FAVORING THE GFS
SOLUTION WHICH IS WEAKER WITH THE FRONT...AND MAKES SENSE GIVEN
THE TIME OF THE YEAR. THE WEAKER THE FRONT...THE LONGER IT WILL
TAKE FOR IT TO CLEAR OUT THE MOISTURE. REGARDLESS...HIGH
TEMPERATURES SHOULD DROP INTO THE LOW 90S THIS WEEKEND DUE TO
EITHER LOWER THICKNESS VALUES AND/OR INCREASED CLOUDS/RAIN.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 99 73 98 76 / 40 10 5 10 20
WACO, TX 77 101 72 100 76 / 20 10 10 10 10
PARIS, TX 73 97 66 95 70 / 40 10 5 10 20
DENTON, TX 73 98 67 97 72 / 30 5 5 20 20
MCKINNEY, TX 73 98 67 96 71 / 40 10 5 10 20
DALLAS, TX 78 99 74 98 76 / 40 10 5 10 20
TERRELL, TX 77 99 70 96 73 / 40 10 5 10 20
CORSICANA, TX 76 100 73 98 75 / 30 10 5 10 20
TEMPLE, TX 75 100 72 100 75 / 20 20 10 10 10
MINERAL WELLS, TX 71 100 66 99 71 / 30 5 5 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
332 PM CDT SUN AUG 12 2012
.DISCUSSION...
ALTHOUGH THE PRIMARY MODEL GUIDANCE REMAINS IN DISAGREEMENT
REGARDING THE CONVECTIVE POTENTIAL THIS EVENING...SHORT-TERM
MESOSCALE TRENDS ARE SUGGESTING THAT THE WETTER NAM...HI-RES WRF
AND HRRR MODELS ARE ON THE RIGHT TRACK. THE COLD FRONT IS MAKING
STEADY PROGRESS TO THE SOUTH AND AT 3 PM HAS PASSED THROUGH
WICHITA FALLS. HOWEVER OBS AND RADAR INDICATE A REGION OF LOW
LEVEL CONFLUENCE FROM ABILENE TO GRAHAM TO BOWIE. THIS AREA WILL
BE THE FAVORABLE REGION FOR INITIATION...AND CONVECTION LOOKS LIKE
IT WILL INITIATE WELL AHEAD OF THE FRONT. LOCAL OBJECTIVE ANALYSIS
INDICATES AN AXIS OF 1000-2500 J/KG OF CAPE ALONG AND EAST OF A
LINE FROM GAINESVILLE TO MINERAL WELLS TO LAMPASAS...WHILE DEEP
LAYER SHEAR IS NOW RUNNING NEAR 35KT ACROSS MUCH OF THE AREA.
UNLIKE PREVIOUS SUMMERTIME CONVECTIVE EVENTS...IT HAS BEEN A
COUPLE MONTHS SINCE WE HAVE HAD THIS MUCH 0-6KM WIND SHEAR
AVAILABLE. GIVEN THE AVAILABLE INSTABILITY AND SHEAR...BRIEF
SUPERCELLS WILL BE POSSIBLE...BUT THE MOST LIKELY CONVECTIVE MODE
WILL BE LINE SEGMENTS. SURFACE TEMPERATURES ARE 105+ ACROSS THE NW
ZONES AHEAD OF THE FRONT...WHILE DEWPOINTS ARE IN THE MID 50S.
THIS WILL CREATE AN EXTREMELY FAVORABLE ENVIRONMENT FOR
DOWNBURSTS. DAMAGING WINDS WILL BE THE PRIMARY THREAT THIS
EVENING...AND BECAUSE DEEP LAYER SHEAR IS AVAILABLE IT WILL ALSO
ENHANCE THE POTENTIAL FOR LINE SEGMENTS PRODUCING ORGANIZED COLD
POOLS. STRONG OUTFLOW WINDS MAY IMPACT A MUCH WIDER AREA THAN
ACTUAL RAINFALL. WILL ALSO INCLUDE A MENTION OF HAIL IN
HWO..ALTHOUGH HOT TEMPS MAY LIMIT HAIL SIZE. THE SCATTERED
CONVECTION IS EXPECTED TO TRACK NORTHWEST TO SOUTHEAST ACROSS THE
CWA THIS EVENING...AND THE HIGHEST POPS WILL BE PLACED IN A BAND
ACROSS THE CENTRAL CWA.
THE TRUE COLD FRONT WILL LIKELY BE TEMPORARILY HELD UP AS OUTFLOW
FROM CONVECTION OVER OUR AREA RESULTS IN PREDOMINANTLY SOUTHERLY
WINDS ON ITS NORTH SIDE. FRONT PROBABLY WILL NOT REACH THE
METROPLEX UNTIL DAYBREAK AND WILL LIKELY PUSH INTO THE SOUTHERN ZONES
BY AFTERNOON. HIGH TEMPERATURES TOMORROW WILL BE TRICKY...WITH
LOCATIONS ALONG AND SOUTH OF THE FRONT IN THE AFTERNOON BENEFITING
FROM SUBSIDENCE WARMING AND THE TEMPS FORECAST HERE MAY BE TOO
LOW. ON THE OTHER HAND...CURRENT OBSERVATIONS SUGGEST THE FRONT
HAS A STRONG PUSH...AND THEREFORE AM LEANING TOWARD THE GUIDANCE
THAT SHOWS SOME DECENT COLD ADVECTION IN THE LOW LEVELS ACROSS THE
NORTH AND NORTHEAST ZONES. WILL RETAIN A MENTION OF LOW POPS IN
THE SOUTHERN ZONES TOMORROW WHERE THE FRONT SHOULD BECOME ACTIVE
IN THE AFTERNOON HOURS.
NORTHWEST FLOW ALOFT WILL REMAIN IN PLACE THROUGH TUESDAY. MODEL
GUIDANCE IS HAVING SOME TIMING DIFFERENCES WITH RESPECT TO THE
NEXT SHORTWAVE...EITHER AS EARLY AS TUESDAY MORNING AND AS LATE AS
OVERNIGHT TUESDAY. INSTABILITY/SHEAR WILL BE SUFFICIENT FOR A MCS
OR REMNANT MCS OUTFLOW TO AFFECT THE AREA FROM OKLAHOMA DURING
THIS TIME. WILL CONTINUE WITH SLIGHT CHANCE POPS TUESDAY AND TUESDAY
NIGHT. SOUTHERLY WINDS RETURN BY WEDNESDAY AND NORTHWEST FLOW
ALOFT WEAKENS. CONVECTIVE POTENTIAL SHOULD ALSO DIMINISH...WHILE
TEMPS RETURN TO NEAR 100 DEGREES AREA WIDE THROUGH THURSDAY.
IN THE EXTENDED...THE STRONGER COLD FRONT STILL LOOKS ON TRACK.
IT SHOULD ARRIVE FRIDAY MORNING AND GRADUALLY WORK SOUTH THROUGH
THE REGION INTO SATURDAY MORNING. WILL CONTINUE WITH LOW POPS
STARTING THURSDAY NIGHT IN THE NORTH...WITH 30 PERCENT EVERYWHERE
FRIDAY. WILL HAVE POPS GRADUALLY CLEAR OUT FROM NORTH TO SOUTH ON
SATURDAY. THE LINGERING POPS ON SATURDAY ARE FAVORING THE GFS
SOLUTION WHICH IS WEAKER WITH THE FRONT...AND MAKES SENSE GIVEN
THE TIME OF THE YEAR. THE WEAKER THE FRONT...THE LONGER IT WILL
TAKE FOR IT TO CLEAR OUT THE MOISTURE. REGARDLESS...HIGH
TEMPERATURES SHOULD DROP INTO THE LOW 90S THIS WEEKEND DUE TO
EITHER LOWER THICKNESS VALUES AND/OR INCREASED CLOUDS/RAIN.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 99 73 98 76 / 40 10 5 10 20
WACO, TX 77 101 72 100 76 / 20 10 10 10 10
PARIS, TX 73 97 66 95 70 / 40 10 5 10 20
DENTON, TX 73 98 67 97 72 / 30 5 5 20 20
MCKINNEY, TX 73 98 67 96 71 / 40 10 5 10 20
DALLAS, TX 78 99 74 98 76 / 40 10 5 10 20
TERRELL, TX 77 99 70 96 73 / 40 10 5 10 20
CORSICANA, TX 76 100 73 98 75 / 30 10 5 10 20
TEMPLE, TX 75 100 72 100 75 / 20 20 10 10 10
MINERAL WELLS, TX 71 100 66 99 71 / 30 5 5 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1238 PM CDT SUN AUG 12 2012
.AVIATION...
18Z TAFS...BREEZY NORTH TO NORTHEAST WINDS INITIALLY THIS AFTERNOON WILL
BEGIN TO GRADUALLY DISSIPATE LATE THIS AFTERNOON AS THE PRESSURE
GRADIENT RELAXES. WIND SPEEDS WILL DIMINISH TO LESS THAN 10 KTS EARLY
THIS EVENING...AND REMAIN LIGHT OVERNIGHT AS THEY GRADUALLY VEER TO
THE SOUTHEAST BY MONDAY MORNING IN RESPONSE TO SURFACE HIGH PRESSURE
SLIDING EASTWARD AND A WEAK LEE TROUGH DEVELOPING TO THE WEST. VFR
CONDITIONS ARE EXPECTED THROUGH THE PERIOD AS MID AND HIGH CLOUDS
CONTINUE TO TRANSLATE EAST/SOUTHEAST OVER THE AREA. A FEW
THUNDERSTORMS MAY TRY TO MAKE IT INTO THE FAR WESTERN PANHANDLES OUT
OF THE HIGHER TERRAIN OF NM AND CO THIS EVENING AND OVERNIGHT...BUT
WILL LIKELY STRUGGLE TO DO SO GIVEN LIMITED INSTABILITY AVAILABLE.
KB
&&
.PREV DISCUSSION... /ISSUED 1142 AM CDT SUN AUG 12 2012/
UPDATE...
REMOVED PRECIPITATION CHANCES FOR THE REST OF TODAY. ANY LIGHT SHOWER
ACTIVITY FROM EARLIER THIS MORNING HAS PUSHED SOUTHEAST OF THE
PANHANDLES. SURFACE COLD FRONT HAS PUSHED SOUTH OF THE
AREA AS WELL...WITH DRIER LOW-LEVEL AIR ADVECTING INTO THE AREA ON
BREEZY NORTH WINDS. MAIN MID/UPPER-LEVEL SHORTWAVE TROUGH CONTINUES
TO PUSH EAST INTO THE MS VALLEY...WITH BROADER SCALE SUBSIDENCE
BEHIND THIS FEATURE LIKELY TRUMPING ANY WEAK LIFT FROM A MINOR MID-
LEVEL RIPPLE SHOWN IN RAP ANALYSIS DATA OVER THE NORTHWEST
PANHANDLES. THE COMBINATION OF CAA ON NORTH/NORTHEAST WINDS AND
CONTINUED MID/HIGH-LEVEL CLOUDS STREAMING ACROSS THE SOUTH/SOUTHWEST
CWA IS EXPECTED TO KEEP FORECAST HIGHS BELOW CONVECTIVE TEMPS THIS
AFTERNOON. CONSIDERING THIS AND THE LACK OF FORCING AT LOW LEVELS AND
ALOFT...THINK THE PANHANDLES WILL REMAIN DRY THROUGH THIS AFTERNOON.
CANNOT TOTALLY RULE OUT A COUPLE OF SPRINKLES FALLING FROM THE MID
DECK ACROSS THE SOUTHERN CWA...BUT DRY LOW LEVELS AND LACK OF MORE
ROBUST DEVELOPMENT ARGUE AGAINST MUCH OF THIS. SOME ISOLATED
CONVECTION MAY TRY TO WORK INTO THE WESTERN PANHANDLES OUT OF THE
HIGHER TERRAIN THIS EVENING. ALSO NUDGED DOWN AFTERNOON HIGH TEMPS
SLIGHTLY DUE TO THE CAA ALONG WITH INCREASED CLOUD COVER ACROSS THE
SOUTH.
KB
PREV DISCUSSION... /ISSUED 628 AM CDT SUN AUG 12 2012/
AVIATION...
12Z TAF CYCLE
HIGH PRESSURE ALOFT WILL MAINTAIN A NORTHWESTERLY FLOW ACROSS THE
THREE TAF SITES THROUGH 12Z MONDAY. ISOLATED CONVECTION MAY MOVE INTO
THE PANHANDLES THIS AFTERNOON AND TONIGHT...HOWEVER CONFIDENCE TOO
LOW THAT ANY CONVECTION WILL AFFECT THE THREE TAF SITES. VFR
CONDITIONS WILL PREVAIL THROUGH 12Z MONDAY. A COLD FRONT WILL MOVE
THROUGH THE AMARILLO TAF SITE BY 15Z TODAY ALLOWING FOR NORTHERLY
WINDS...NORTHERLY WINDS WILL PREVAIL AT THE DALHART AND GUYMON TAF
SITES. WINDS 5 TO 15 KNOTS THIS MORNING WILL INCREASE TO AROUND 15 TO
25 KNOTS WITH HIGHER GUSTS AFTER 15Z TODAY...AND THEN DIMINISH TO 5
TO 10 KNOTS OR LESS AFTER 00Z TO 02Z MONDAY.
SCHNEIDER
PREV DISCUSSION... /ISSUED 355 AM CDT SUN AUG 12 2012/
DISCUSSION...
SCATTERED SHOWER ARE ACCOMPANYING A SURFACE TROUGH THAT IS SLOWLY
MOVING ACROSS THE TEXAS AND OKLAHOMA PANHANDLES THIS SUNDAY MORNING.
THE TROUGH IS FAR IN ADVANCE OF A COLD FRONT EXPECTED TO MOVE THROUGH
THE AREA TODAY. THIS SLOWER PROGRESSION OF THE FRONT IS MORE
REFLECTED IN THE SLOWER GFS SOLUTION RATHER THAN THE QUICKER NAM. AS
SUCH HAVE STUCK CLOSER TO THE GFS FOR THE FORECAST AND KEPT RAIN
CHANCES LOW SUNDAY THROUGH MONDAY.
NORTHWEST FLOW ALOFT WILL BE WELL ESTABLISHED BY MONDAY NIGHT AND
BRING A SERIES OF SHORTWAVES ACROSS THE PANHANDLES MONDAY NIGHT
THROUGH THURSDAY NIGHT. MONDAY NIGHT INTO TUESDAY WILL HAVE THE
BETTER CHANCE FOR WIDESPREAD RAIN FOR THE AREA AS A STRONGER
SHORTWAVE FOR THE SERIES DIVES SOUTHEASTWARD FROM EASTERN COLORADO.
THERE STILL REMAINS A DISCONTINUITY BETWEEN THE ECMWF AND GFS
CONCERNING A SECONDARY COLD FRONT FOR THE THURSDAY/FRIDAY TIME FRAME.
HOWEVER...THE MOST RECENT ECMWF HAS SLOWED THE FRONT PROGRESSION
SLIGHTLY COMPARED TO PREVIOUS RUNS...EDGING IT CLOSER TO THE GFS
SOLUTION. STUCK WITH THE CONSISTENT GFS...AND HAVE THE FRONT SLOWLY
MOVING THROUGH THE AREA DURING THE EARLY MORNING HOURS FRIDAY. THIS
SLOWER PROGRESSION SUPPORTS HIGHER POPS FOR FRIDAY MORNING AND HIGH
TEMPERATURES FOR FRIDAY IN THE LOW TO MID 80S. BEHIND THE FRONT
RETURN FLOW WILL QUICKLY RETURN AND START A WARMING TREND THROUGH THE
WEEKEND.
FIRE WEATHER...
A SURFACE TROUGH HAS SHIFTED THE WINDS TO THE NORTH SUNDAY MORNING AS
SCATTERED SHOWERS MOVE ACROSS THE AREA. EXPECT WINDS TO INCREASE
DURING THE DAY TOPPING OUT AROUND 20 MPH AS RELATIVE HUMIDITY VALUES
DROP TO NEAR 20 PERCENT. WINDS ARE EXPECTED TO DECREASE DURING THE
AFTERNOON HOURS. BY THIS EVENING RELATIVE HUMIDITY VALUES BEING A
STEADY RECOVERY AND MINIMUM RELATIVE HUMIDITY VALUES SHOULD REMAIN
ABOVE 20 PERCENT THROUGH THE WEEK. A SECONDARY FRONT EARLY FRIDAY
MORNING WILL PROVIDE ANOTHER WIND SHIFT TO THE NORTH AND RAIN CHANCES.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
02/08
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1142 AM CDT SUN AUG 12 2012
.UPDATE...
REMOVED PRECIPITATION CHANCES FOR THE REST OF TODAY. ANY LIGHT SHOWER
ACTIVITY FROM EARLIER THIS MORNING HAS PUSHED SOUTHEAST OF THE
PANHANDLES. SURFACE COLD FRONT HAS PUSHED SOUTH OF THE
AREA AS WELL...WITH DRIER LOW-LEVEL AIR ADVECTING INTO THE AREA ON
BREEZY NORTH WINDS. MAIN MID/UPPER-LEVEL SHORTWAVE TROUGH CONTINUES
TO PUSH EAST INTO THE MS VALLEY...WITH BROADER SCALE SUBSIDENCE
BEHIND THIS FEATURE LIKELY TRUMPING ANY WEAK LIFT FROM A MINOR MID-
LEVEL RIPPLE SHOWN IN RAP ANALYSIS DATA OVER THE NORTHWEST
PANHANDLES. THE COMBINATION OF CAA ON NORTH/NORTHEAST WINDS AND
CONTINUED MID/HIGH-LEVEL CLOUDS STREAMING ACROSS THE SOUTH/SOUTHWEST
CWA IS EXPECTED TO KEEP FORECAST HIGHS BELOW CONVECTIVE TEMPS THIS
AFTERNOON. CONSIDERING THIS AND THE LACK OF FORCING AT LOW LEVELS AND
ALOFT...THINK THE PANHANDLES WILL REMAIN DRY THROUGH THIS AFTERNOON.
CANNOT TOTALLY RULE OUT A COUPLE OF SPRINKLES FALLING FROM THE MID
DECK ACROSS THE SOUTHERN CWA...BUT DRY LOW LEVELS AND LACK OF MORE
ROBUST DEVELOPMENT ARGUE AGAINST MUCH OF THIS. SOME ISOLATED
CONVECTION MAY TRY TO WORK INTO THE WESTERN PANHANDLES OUT OF THE
HIGHER TERRAIN THIS EVENING. ALSO NUDGED DOWN AFTERNOON HIGH TEMPS
SLIGHTLY DUE TO THE CAA ALONG WITH INCREASED CLOUD COVER ACROSS THE
SOUTH.
KB
&&
.PREV DISCUSSION... /ISSUED 628 AM CDT SUN AUG 12 2012/
AVIATION...
12Z TAF CYCLE
HIGH PRESSURE ALOFT WILL MAINTAIN A NORTHWESTERLY FLOW ACROSS THE
THREE TAF SITES THROUGH 12Z MONDAY. ISOLATED CONVECTION MAY MOVE INTO
THE PANHANDLES THIS AFTERNOON AND TONIGHT...HOWEVER CONFIDENCE TOO
LOW THAT ANY CONVECTION WILL AFFECT THE THREE TAF SITES. VFR
CONDITIONS WILL PREVAIL THROUGH 12Z MONDAY. A COLD FRONT WILL MOVE
THROUGH THE AMARILLO TAF SITE BY 15Z TODAY ALLOWING FOR NORTHERLY
WINDS...NORTHERLY WINDS WILL PREVAIL AT THE DALHART AND GUYMON TAF
SITES. WINDS 5 TO 15 KNOTS THIS MORNING WILL INCREASE TO AROUND 15 TO
25 KNOTS WITH HIGHER GUSTS AFTER 15Z TODAY...AND THEN DIMINISH TO 5
TO 10 KNOTS OR LESS AFTER 00Z TO 02Z MONDAY.
SCHNEIDER
PREV DISCUSSION... /ISSUED 355 AM CDT SUN AUG 12 2012/
DISCUSSION...
SCATTERED SHOWER ARE ACCOMPANYING A SURFACE TROUGH THAT IS SLOWLY
MOVING ACROSS THE TEXAS AND OKLAHOMA PANHANDLES THIS SUNDAY MORNING.
THE TROUGH IS FAR IN ADVANCE OF A COLD FRONT EXPECTED TO MOVE THROUGH
THE AREA TODAY. THIS SLOWER PROGRESSION OF THE FRONT IS MORE
REFLECTED IN THE SLOWER GFS SOLUTION RATHER THAN THE QUICKER NAM. AS
SUCH HAVE STUCK CLOSER TO THE GFS FOR THE FORECAST AND KEPT RAIN
CHANCES LOW SUNDAY THROUGH MONDAY.
NORTHWEST FLOW ALOFT WILL BE WELL ESTABLISHED BY MONDAY NIGHT AND
BRING A SERIES OF SHORTWAVES ACROSS THE PANHANDLES MONDAY NIGHT
THROUGH THURSDAY NIGHT. MONDAY NIGHT INTO TUESDAY WILL HAVE THE
BETTER CHANCE FOR WIDESPREAD RAIN FOR THE AREA AS A STRONGER
SHORTWAVE FOR THE SERIES DIVES SOUTHEASTWARD FROM EASTERN COLORADO.
THERE STILL REMAINS A DISCONTINUITY BETWEEN THE ECMWF AND GFS
CONCERNING A SECONDARY COLD FRONT FOR THE THURSDAY/FRIDAY TIME FRAME.
HOWEVER...THE MOST RECENT ECMWF HAS SLOWED THE FRONT PROGRESSION
SLIGHTLY COMPARED TO PREVIOUS RUNS...EDGING IT CLOSER TO THE GFS
SOLUTION. STUCK WITH THE CONSISTENT GFS...AND HAVE THE FRONT SLOWLY
MOVING THROUGH THE AREA DURING THE EARLY MORNING HOURS FRIDAY. THIS
SLOWER PROGRESSION SUPPORTS HIGHER POPS FOR FRIDAY MORNING AND HIGH
TEMPERATURES FOR FRIDAY IN THE LOW TO MID 80S. BEHIND THE FRONT
RETURN FLOW WILL QUICKLY RETURN AND START A WARMING TREND THROUGH THE
WEEKEND.
FIRE WEATHER...
A SURFACE TROUGH HAS SHIFTED THE WINDS TO THE NORTH SUNDAY MORNING AS
SCATTERED SHOWERS MOVE ACROSS THE AREA. EXPECT WINDS TO INCREASE
DURING THE DAY TOPPING OUT AROUND 20 MPH AS RELATIVE HUMIDITY VALUES
DROP TO NEAR 20 PERCENT. WINDS ARE EXPECTED TO DECREASE DURING THE
AFTERNOON HOURS. BY THIS EVENING RELATIVE HUMIDITY VALUES BEING A
STEADY RECOVERY AND MINIMUM RELATIVE HUMIDITY VALUES SHOULD REMAIN
ABOVE 20 PERCENT THROUGH THE WEEK. A SECONDARY FRONT EARLY FRIDAY
MORNING WILL PROVIDE ANOTHER WIND SHIFT TO THE NORTH AND RAIN CHANCES.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
08/02
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
924 PM EDT MON AUG 13 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXIT THE REGION TONIGHT AND MAKE WAY FOR AN
APPROACHING COLD FRONT. THIS FRONT WILL MOVE THROUGH THE REGION
TOMORROW EVENING. IN ITS WAKE...HIGH PRESSURE WILL RETURN TO THE
REGION WITH YET ANOTHER...AND PERHAPS STRONGER...COLD FRONT SLATED
TO CROSS THE REGION FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 855 PM EDT MONDAY...
MOISTURE GRADUALLY RETURNING TO THE AREA TONIGHT WITH EVENING
RAOBS SHOWING ONLY A DRY LAYER REMAINING IN THE BOUNDARY LAYER AND
ANOTHER SMALL CAPPED POCKET ALOFT. INITIAL RESIDUAL BAND OF SHRA
WELL AHEAD OF THE FRONT ALONG THE MISS RIVER HAS BASICALLY FADED
CROSSING THE FAR WESTERN RIDGES BUT HAS ALLOWED FOR SOME INCREASE
IN WEAK INSTABILITY AS DEWPOINTS START TO SLOWLY CREEP UP. APPEARS
WITH THIS TREND CONTINUING OVERNIGHT THAT MAY SEE ISOLATED SHRA
AFFECT THE WEST...THEN PERHAPS A BAND OR TWO LATE ESPCLY NW
SECTIONS AS THE PRE-FRONTAL ZONE APPROACHES TOWARD MORNING PER THE
LATEST HRRR. THUS MADE ONLY SMALL ADJUSTS TO THE EARLIER EVENING
UPDATE WITH A SCATTERING OF 20ISH POPS PAST MIDNIGHT...THEN A BIT
HIGHER CHANCE WEST LATE. OTRW PLENTY OF CLOUDS AROUND TO MAKE
TEMPS A LITTLE MORE TRICKY AS THINGS BECOME MORE HUMID OVERNIGHT.
THINK SOME DEGREE OF CLDNS WILL LINGER THEREFORE BUMPED UP LOWS
A FEW DEGREES TO THE WARM SIDE OF MOS INCLUDING THE LATEST LAV.
AS OF 612 PM EDT MONDAY...
EARLY EVENING UPDATE MAINLY TO REDUCE POPS ACROSS THE SW THIS
EVENING GIVEN MAIN AXIS OF SHRA PASSING TO THE SW...AND THEN TO
INCLUDE SOME CHANCE POPS AFTER MIDNIGHT ACROSS THE WEST PER SHRA
DEVELOPMENT BEHIND THE PRE-FRONTAL RH LOBE ATTM. THIS SUPPORTED
VIA THE LATEST HRRR WHICH BRINGS SOME OF THIS LEFTOVER CONVECTION
INTO THE WESTERN ZONES LATE IN CONJUNCTION WITH MOISTENING OF MID
LEVELS OFF LATEST FORECAST RAOBS. ALSO LOWERED TEMPS SOME OVER THE
SW WHERE HEATING WAS LESS DUE TO EARLY ARRIVAL OF THE MID DECK
CANOPY.
AS OF 315 PM EDT MONDAY...
INFLUENCE OF HIGH PRESSURE WILL CONTINUE THROUGH THIS EVENING.
PRECIPITATION WILL BE VERY LIMITED...IF EXISTS AT ALL. THE GREAT
POTENTIAL WILL BE ALONG THE CREST OF THE BLUE RIDGE SOUTHWEST OF
FLOYD INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA...AND IN AREAS
ALONG AND NEAR THE NC/VA BORDER.
OVERNIGHT...MID TO HIGH LEVEL CLOUD COVER IS EXPECTED TO OVERSPREAD
THE REGION AS DEBRIS CLOUD COVER FROM AN APPROACHING COLD FRONT
ADVECTS INTO THE REGION. THIS WILL HAVE THE RESULT OF
LIMITED...ALTHOUGH NOT COMPLETELY PREVENTING...THE DEVELOPMENT OF
PRIMARILY LATE NIGHT MOUNTAIN VALLEY FOG...ESPECIALLY OVER PARTS OF
THE GREENBRIER AND NEW RIVER VALLEYS. SOME ISOLATED TO SCATTERED
SHOWERS WILL BE POSSIBLE OVER SOUTHEAST WEST VIRGINIA BY SUNRISE IN
ASSOCIATION WITH THE APPROACHING FRONT.
ON TUESDAY...THE FRONT WILL DRAW EVEN CLOSE TO THE REGION DURING THE
DAY TUESDAY. ISENTROPIC LIFT IN ADVANCE OF THE FRONT WILL HELP TO
PROVIDE GENEROUS COVERAGE OF SHOWERS AND STORMS BY MIDDAY ACROSS ALL
BUT THE FAR EASTERN SECTIONS OF THE REGION. BY THE LATE
AFTERNOON...ALL AREAS ARE EXPECTED TO HAVE AT LEAST SCATTERED
COVERAGE OF SHOWERS AND STORMS...WITH THE GREATEST COVERAGE ACROSS
SOUTHEAST WEST VIRGINIA AND AREAS ALONG AND NEAR THE CREST OF THE
BLUE RIDGE.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 112 PM EDT MONDAY...
JUST SOME MINOR TWEAKS TO THE PREVIOUS FORECAST FOR THIS TIME
PERIOD. MODELS SHOW A DECENT SHORTWAVE SHIFTING EAST ACROSS THE ARE
TUE NIGHT INTO WED MORNING...SO EXPECT TO SEE LINGERING SHOWERS OR
STORMS IN THE EAST TUE EVENING AND SOME UPSLOPE ENHANCE SHOWERS
ACROSS THE MTNS INTO WED MORNING BEFORE SUBSIDENCE STARTS TO DRY THE
COLUMN OUT SUBSTANTIALLY. THE UPPER FLOW STAYS IN A GENERAL WRLY
DIRECTION AFTER THE FRONTAL PASSAGE AND ONLY EXPECTING MEAGER DROPS
IN THE DEWPOINTS WITH TEMPS REMAINING JUST AS WARM AS TUESDAY.
A WEAK HIGH PRESSURE SYSTEM LINGERS ACROSS THE AREA INTO THURSDAY
DURING WHICH SKIES SHOULD REMAIN CLEAR-PARTLY CLOUDY.
SHOULD SEE INCREASING CLOUDS AHEAD OF NEXT TROUGH AND SFC FRONT LATE
THU NIGHT...BUT ANY PRECIP SHOULD HOLD OFF UNTIL FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 112 PM EDT MONDAY...
POSITIVE PNA PATTERN WITH TROUGH IN THE EASTERN U.S./TROUGH WEST
COAST WILL BE THE UPPER AIR FLOW INTO THE EXTENDED PERIOD WITH SOME
BREAKDOWN IN THE WRN RIDGE AFTER NEXT MONDAY.
THE NEXT FRONT WILL SLIDE INTO THE AREA FRIDAY INTO SATURDAY. UPPER
PATTERN SUPPORTS SLOWER MOVEMENT OF FRONT AND COULD SEE THE FRONT
STALL JUST SOUTH AND EAST OF THE FORECAST AREA OVER THE WEEKEND. THE
ECMWF ALLUDES TO MORE CLOUDS ACROSS THE SRN CWA INTO SUNDAY WITH AN
INCREASE IN PRECIP CHANCES HEADING INTO MONDAY ACROSS SRN VA/NRN NC.
FOR NOW WILL KEEP THE AREA DRY MONDAY...PER HPC AND ENSEMBLE
LEANINGS...GIVEN THE TROUGH DOES LOOK TO DEEPEN JUST ENOUGH.
SO FOR THIS PERIOD...THINK AT LEAST A CHANCE POPS WARRANTED FRI-SAT
WITH SOME DRYING ACROSS THE REGION SAT NIGHT-SUN WITH A FEW
LINGERING SHOWERS IN THE PIEDMONT...THEN MAINLY DRY WITH INCREASING
CLOUDS AROUND SUN NIGHT INTO MONDAY ACROSS THE PIEDMONT SOUTHWEST
INTO THE NC FOOTHILLS.
TEMPS THIS PERIOD SHOULD COOL OFF AGAIN TOWARD WHAT WE HAD THIS PAST
WEEKEND WITH HIGHS IN THE 70S WEST TO LOWER 80S EAST...WHILE LOWS AT
NIGHT RANGE FROM THE LOWER 50S WEST TO LOWER 60S EAST.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
AS OF 815 PM EDT MONDAY...
VFR CONDITIONS ARE EXPECTED THROUGH THE EVENING INTO THE OVERNIGHT
HOURS. OVERNIGHT...MID TO HIGH LEVEL CLOUDINESS WILL OVERSPREAD
THE AREA IN ADVANCE OF OUR NEXT COLD FRONT. THIS WILL LIMIT THE
EXTENT OF ANY MVFR MOUNTAIN OR RIVER VALLEY FOG. THE ADVANCING
COLD FRONT WILL PROMPT AN INCREASE IN SHOWERS AND STORMS DURING
THE DAY TOMORROW. ANTICIPATE THE KBLF - KLWB AREA WILL HAVE
SCATTERED SHOWERS AND PERHAPS A RUMBLE OR TWO OF THUNDER AFTER
14Z...10AM...WITH THE BEST CHANCES AFTER 16Z...12PM. HAVE
INDICATED VCSH STARTING AT 14Z INCREASING TO TSRA IN THE WEATHER
GROUP AT THESE TAF SITES TOMORROW TO INDICATE THIS. OTHER SITE
WILL HAVE INCREASING CHANCES OF SHOWERS THROUGHOUT THE DAY AND
HAVE ADDED VCSH TO ALL TAF SITES WITH THE APPROPRIATE TIME LAG.
LOCALIZED SUB-VFR CIGS AND VSBYS WILL BE POSSIBLE UNDER THE
STRONGEST CONVECTIVE CELLS TUESDAY AND TUESDAY EVENING.
NIGHTTIME SUB-VFR MOUNTAIN OR RIVER VALLEY FOG WILL BE POSSIBLE
THIS WEEK...ESPECIALLY IN AREAS THAT RECEIVE RAIN ON TUESDAY.
INCREASED COVERAGE OF SHOWERS AND STORMS AGAIN FRIDAY INTO
SATURDAY WITH THE PASSAGE OF THE NEXT COLD FRONT.
&&
.EQUIPMENT...
THE NOAA WEATHER RADIO FROM ROANOKE VIRGINIA IS OFF THE AIR
TONIGHT LIKELY DUE TO A PHONE PROBLEM. RETURN TO SERVICE TIME IS
UNKNOWN AS TECHNICIANS WORK ON THE PROBLEM.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS/JH
SHORT TERM...WP
LONG TERM...WP
AVIATION...JC
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
820 PM EDT MON AUG 13 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXIT THE REGION TONIGHT AND MAKE WAY FOR AN
APPROACHING COLD FRONT. THIS FRONT WILL MOVE THROUGH THE REGION
TOMORROW EVENING. IN ITS WAKE...HIGH PRESSURE WILL RETURN TO THE
REGION WITH YET ANOTHER...AND PERHAPS STRONGER...COLD FRONT SLATED
TO CROSS THE REGION FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 612 PM EDT MONDAY...
EARLY EVENING UPDATE MAINLY TO REDUCE POPS ACROSS THE SW THIS
EVENING GIVEN MAIN AXIS OF SHRA PASSING TO THE SW...AND THEN TO
INCLUDE SOME CHANCE POPS AFTER MIDNIGHT ACROSS THE WEST PER SHRA
DEVELOPMENT BEHIND THE PRE-FRONTAL RH LOBE ATTM. THIS SUPPORTED
VIA THE LATEST HRRR WHICH BRINGS SOME OF THIS LEFTOVER CONVECTION
INTO THE WESTERN ZONES LATE IN CONJUNCTION WITH MOISTENING OF MID
LEVELS OFF LATEST FORECAST RAOBS. ALSO LOWERED TEMPS SOME OVER THE
SW WHERE HEATING WAS LESS DUE TO EARLY ARRIVAL OF THE MID DECK
CANOPY.
AS OF 315 PM EDT MONDAY...
INFLUENCE OF HIGH PRESSURE WILL CONTINUE THROUGH THIS EVENING.
PRECIPITATION WILL BE VERY LIMITED...IF EXISTS AT ALL. THE GREAT
POTENTIAL WILL BE ALONG THE CREST OF THE BLUE RIDGE SOUTHWEST OF
FLOYD INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA...AND IN AREAS
ALONG AND NEAR THE NC/VA BORDER.
OVERNIGHT...MID TO HIGH LEVEL CLOUD COVER IS EXPECTED TO OVERSPREAD
THE REGION AS DEBRIS CLOUD COVER FROM AN APPROACHING COLD FRONT
ADVECTS INTO THE REGION. THIS WILL HAVE THE RESULT OF
LIMITED...ALTHOUGH NOT COMPLETELY PREVENTING...THE DEVELOPMENT OF
PRIMARILY LATE NIGHT MOUNTAIN VALLEY FOG...ESPECIALLY OVER PARTS OF
THE GREENBRIER AND NEW RIVER VALLEYS. SOME ISOLATED TO SCATTERED
SHOWERS WILL BE POSSIBLE OVER SOUTHEAST WEST VIRGINIA BY SUNRISE IN
ASSOCIATION WITH THE APPROACHING FRONT.
ON TUESDAY...THE FRONT WILL DRAW EVEN CLOSE TO THE REGION DURING THE
DAY TUESDAY. ISENTROPIC LIFT IN ADVANCE OF THE FRONT WILL HELP TO
PROVIDE GENEROUS COVERAGE OF SHOWERS AND STORMS BY MIDDAY ACROSS ALL
BUT THE FAR EASTERN SECTIONS OF THE REGION. BY THE LATE
AFTERNOON...ALL AREAS ARE EXPECTED TO HAVE AT LEAST SCATTERED
COVERAGE OF SHOWERS AND STORMS...WITH THE GREATEST COVERAGE ACROSS
SOUTHEAST WEST VIRGINIA AND AREAS ALONG AND NEAR THE CREST OF THE
BLUE RIDGE.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 112 PM EDT MONDAY...
JUST SOME MINOR TWEAKS TO THE PREVIOUS FORECAST FOR THIS TIME
PERIOD. MODELS SHOW A DECENT SHORTWAVE SHIFTING EAST ACROSS THE ARE
TUE NIGHT INTO WED MORNING...SO EXPECT TO SEE LINGERING SHOWERS OR
STORMS IN THE EAST TUE EVENING AND SOME UPSLOPE ENHANCE SHOWERS
ACROSS THE MTNS INTO WED MORNING BEFORE SUBSIDENCE STARTS TO DRY THE
COLUMN OUT SUBSTANTIALLY. THE UPPER FLOW STAYS IN A GENERAL WRLY
DIRECTION AFTER THE FRONTAL PASSAGE AND ONLY EXPECTING MEAGER DROPS
IN THE DEWPOINTS WITH TEMPS REMAINING JUST AS WARM AS TUESDAY.
A WEAK HIGH PRESSURE SYSTEM LINGERS ACROSS THE AREA INTO THURSDAY
DURING WHICH SKIES SHOULD REMAIN CLEAR-PARTLY CLOUDY.
SHOULD SEE INCREASING CLOUDS AHEAD OF NEXT TROUGH AND SFC FRONT LATE
THU NIGHT...BUT ANY PRECIP SHOULD HOLD OFF UNTIL FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 112 PM EDT MONDAY...
POSITIVE PNA PATTERN WITH TROUGH IN THE EASTERN U.S./TROUGH WEST
COAST WILL BE THE UPPER AIR FLOW INTO THE EXTENDED PERIOD WITH SOME
BREAKDOWN IN THE WRN RIDGE AFTER NEXT MONDAY.
THE NEXT FRONT WILL SLIDE INTO THE AREA FRIDAY INTO SATURDAY. UPPER
PATTERN SUPPORTS SLOWER MOVEMENT OF FRONT AND COULD SEE THE FRONT
STALL JUST SOUTH AND EAST OF THE FORECAST AREA OVER THE WEEKEND. THE
ECMWF ALLUDES TO MORE CLOUDS ACROSS THE SRN CWA INTO SUNDAY WITH AN
INCREASE IN PRECIP CHANCES HEADING INTO MONDAY ACROSS SRN VA/NRN NC.
FOR NOW WILL KEEP THE AREA DRY MONDAY...PER HPC AND ENSEMBLE
LEANINGS...GIVEN THE TROUGH DOES LOOK TO DEEPEN JUST ENOUGH.
SO FOR THIS PERIOD...THINK AT LEAST A CHANCE POPS WARRANTED FRI-SAT
WITH SOME DRYING ACROSS THE REGION SAT NIGHT-SUN WITH A FEW
LINGERING SHOWERS IN THE PIEDMONT...THEN MAINLY DRY WITH INCREASING
CLOUDS AROUND SUN NIGHT INTO MONDAY ACROSS THE PIEDMONT SOUTHWEST
INTO THE NC FOOTHILLS.
TEMPS THIS PERIOD SHOULD COOL OFF AGAIN TOWARD WHAT WE HAD THIS PAST
WEEKEND WITH HIGHS IN THE 70S WEST TO LOWER 80S EAST...WHILE LOWS AT
NIGHT RANGE FROM THE LOWER 50S WEST TO LOWER 60S EAST.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 815 PM EDT MONDAY...
VFR CONDITIONS ARE EXPECTED THROUGH THE EVENING INTO THE OVERNIGHT
HOURS. OVERNIGHT...MID TO HIGH LEVEL CLOUDINESS WILL OVERSPREAD
THE AREA IN ADVANCE OF OUR NEXT COLD FRONT. THIS WILL LIMIT THE
EXTENT OF ANY MVFR MOUNTAIN OR RIVER VALLEY FOG. THE ADVANCING
COLD FRONT WILL PROMPT AN INCREASE IN SHOWERS AND STORMS DURING
THE DAY TOMORROW. ANTICIPATE THE KBLF - KLWB AREA WILL HAVE
SCATTERED SHOWERS AND PERHAPS A RUMBLE OR TWO OF THUNDER AFTER
14Z...10AM...WITH THE BEST CHANCES AFTER 16Z...12PM. HAVE
INDICATED VCSH STARTING AT 14Z INCREASING TO TSRA IN THE WEATHER
GROUP AT THESE TAF SITES TOMORROW TO INDICATE THIS. OTHER SITE
WILL HAVE INCREASING CHANCES OF SHOWERS THROUGHOUT THE DAY AND
HAVE ADDED VCSH TO ALL TAF SITES WITH THE APPROPRIATE TIME LAG.
LOCALIZED SUB-VFR CIGS AND VSBYS WILL BE POSSIBLE UNDER THE
STRONGEST CONVECTIVE CELLS TUESDAY AND TUESDAY EVENING.
NIGHTTIME SUB-VFR MOUNTAIN OR RIVER VALLEY FOG WILL BE POSSIBLE
THIS WEEK...ESPECIALLY IN AREAS THAT RECEIVE RAIN ON TUESDAY.
INCREASED COVERAGE OF SHOWERS AND STORMS AGAIN FRIDAY INTO
SATURDAY WITH THE PASSAGE OF THE NEXT COLD FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS/JH
SHORT TERM...WP
LONG TERM...WP
AVIATION...JC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1043 PM CDT MON AUG 13 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SHORTWAVE
TROUGHING MOVING ACROSS EASTERN WISCONSIN EARLY THIS AFTERNOON. A
SECONDARY FRONT IS MOVING INTO NORTHWEST WISCONSIN AS WELL WHICH IS
INTERACTING WITH STEEP LOW LEVEL LAPSE RATES AND 200-400 J/KG OF ML
CAPE TO CREATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
LOOKING UPSTREAM...PLENTY OF CU OVER MINNESOTA AND SOUTH-CENTRAL
CANADA WHERE ADDITIONAL WEAK SHORTWAVE ENERGY IS MOVING INTO THE
WESTERN LAKE WINNIPEG REGION. THE MAIN FORECAST CONCERNS INCLUDE
TIMING THE END OF PRECIP CHANCES THIS EVENING...AND SMALL PRECIP
CHANCE TOMORROW AFTERNOON.
TONIGHT...THE SHORTWAVE TROUGH OVER EASTERN WISCONSIN WILL EXIT
DURING THE EVENING AND SHOWERS WILL BE WEAKENING WITH LOSS OF
HEATING. THE LATEST SHORT RANGE GUIDANCE AND ESTIMATES FROM STORM
MOTION SUGGEST SHOWERS WILL LINGER INTO EARLY THIS EVENING OVER FAR
NE INTO CENTRAL WISCONSIN...SO WILL KEEP A SHOWER MENTION TROUGH MID
EVENING. CLOUDS MAY BE SLOWER TO DISSIPATE AS A WEAK FRONT WASHES
OUT ACROSS THE REGION. WILL SHOW PARTLY CLOUDY CONDITIONS BECOMING
MOSTLY CLEAR OVERNIGHT. LOW LEVEL MOISTURE IS NOT REALLY ALL THAT
DRY THOUGH...SO WITH CLEARING SKIES AND LIGHT WINDS...COULD SEE
PATCHY FOG DEVELOP LATE...ESPECIALLY OVER THE COLD SPOTS OF N-C
WISCONSIN. LOWS IN THE UPPER 40S NORTH TO MID 50S SOUTH.
TUESDAY...NORTHWEST FLOW WILL PREVAIL ALOFT WHILE WEAK HIGH PRESSURE
WILL BE AT THE SURFACE. A WEAK SHORTWAVE NOW OVER SOUTHERN MANITOBA
WILL SLOWLY PASS ACROSS THE STATE. PROGGED SOUNDINGS LOOK SIMILAR TO
TODAYS..WITH STEEP LOW LEVEL LAPSE RATES AND ML CAPES UP TO 500 J/KG
DEVELOPING IN THE AFTERNOON. WILL HAVE WEAK CONVERGENCE ALONG THE
LAKE BREEZE FOR A FOCUS MECHANISM SO LIKE HAVING A CHANCE OF SHOWERS
OVER NORTHERN WISCONSIN FOR THE AFTERNOON. WARMED HIGHS UP A COUPLE
DEGREES AND WENT MID 70S TO LOW 80S.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. OTHER THAN TIMING
OF THE COLD FRONT LATE WEDNESDAY NIGHT OR THURSDAY THE MEDIUM
RANGE MODELS ARE IN PRETTY GOOD AGREEMENT INTO EARLY NEXT WEEK.
WEAK UPPER RIDGING SHOULD PROVIDE DRY WEATHER TUESDAY NIGHT AND
WEDNESDAY. UPPER DIFFLUENCE INCREASES WEDNESDAY NIGHT AS THE UPPER
TOUGH APPROACHES AND LOW LEVEL MOISTURE INCREASES AS WELL. SHOULD
GET A GOOD AREA OF SHOWERS AND THUNDERSTORMS MOVING INTO THE
WESTERN PART OF THE FORECAST AREA LATE WEDNESDAY NIGHT AND ACROSS
THE EAST THURSDAY MORNING. TIMING OF THE FRONT IS NOT IDEAL FOR
SEVERE THUNDERSTORMS SO THINK THAT THE SEVERE THREAT IS LOW.
UPPER FLOW BECOMES NORTHWEST FRIDAY AND SATURDAY AND A LARGE
SURFACE HIGH DROPS IN FROM THE NORTHERN PLAINS. WHILE IT SHOULD BE
GENERALLY DRY THERE IS A SMALL CHANCE OF MAINLY AFTERNOON SHOWERS
ACROSS THE NORTH IN THE COLD AND CYCLONIC FLOW. SURFACE HIGH
SHOULD BE RIGHT OVER THE AREA FRIDAY NIGHT AND WOULD NOT BE
SURPRISED TO SEE SOME FROST IN THE FAR NORTH.
&&
.AVIATION...ISOLD SHRA SHOULD DISSIPATE BEFORE THE NEW TAF
ISSUANCE OCCURS...SO WILL NOT HAVE ANY MENTION OF PCPN IN THE 06Z
TAFS. CLEARING SKIES AND LIGHT WINDS WILL ALLOW AREAS OF FOG TO
DEVELOP OVERNIGHT...WITH LOCAL VLIFR VSBYS/CIGS POSSIBLE IN AREAS
THAT RECEIVED SIGNIFICANT RAINFALL TODAY. HAVE CONTINUED THE TEMPO
GROUP FOR 1/2SM/VV002 AT RHI...AND MENTIONED VSBYS AS LOW AS 1SM
AT GRB. ANY FOG THAT DEVELOPS SHOULD MIX OUT EARLY TUESDAY
MORNING...FOLLOWED BY SCT CUMULUS CLOUDS DEVELOPING IN THE LATE
MORNING AND AFTERNOON.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
638 PM CDT MON AUG 13 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SHORTWAVE
TROUGHING MOVING ACROSS EASTERN WISCONSIN EARLY THIS AFTERNOON. A
SECONDARY FRONT IS MOVING INTO NORTHWEST WISCONSIN AS WELL WHICH IS
INTERACTING WITH STEEP LOW LEVEL LAPSE RATES AND 200-400 J/KG OF ML
CAPE TO CREATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
LOOKING UPSTREAM...PLENTY OF CU OVER MINNESOTA AND SOUTH-CENTRAL
CANADA WHERE ADDITIONAL WEAK SHORTWAVE ENERGY IS MOVING INTO THE
WESTERN LAKE WINNIPEG REGION. THE MAIN FORECAST CONCERNS INCLUDE
TIMING THE END OF PRECIP CHANCES THIS EVENING...AND SMALL PRECIP
CHANCE TOMORROW AFTERNOON.
TONIGHT...THE SHORTWAVE TROUGH OVER EASTERN WISCONSIN WILL EXIT
DURING THE EVENING AND SHOWERS WILL BE WEAKENING WITH LOSS OF
HEATING. THE LATEST SHORT RANGE GUIDANCE AND ESTIMATES FROM STORM
MOTION SUGGEST SHOWERS WILL LINGER INTO EARLY THIS EVENING OVER FAR
NE INTO CENTRAL WISCONSIN...SO WILL KEEP A SHOWER MENTION TROUGH MID
EVENING. CLOUDS MAY BE SLOWER TO DISSIPATE AS A WEAK FRONT WASHES
OUT ACROSS THE REGION. WILL SHOW PARTLY CLOUDY CONDITIONS BECOMING
MOSTLY CLEAR OVERNIGHT. LOW LEVEL MOISTURE IS NOT REALLY ALL THAT
DRY THOUGH...SO WITH CLEARING SKIES AND LIGHT WINDS...COULD SEE
PATCHY FOG DEVELOP LATE...ESPECIALLY OVER THE COLD SPOTS OF N-C
WISCONSIN. LOWS IN THE UPPER 40S NORTH TO MID 50S SOUTH.
TUESDAY...NORTHWEST FLOW WILL PREVAIL ALOFT WHILE WEAK HIGH PRESSURE
WILL BE AT THE SURFACE. A WEAK SHORTWAVE NOW OVER SOUTHERN MANITOBA
WILL SLOWLY PASS ACROSS THE STATE. PROGGED SOUNDINGS LOOK SIMILAR TO
TODAYS..WITH STEEP LOW LEVEL LAPSE RATES AND ML CAPES UP TO 500 J/KG
DEVELOPING IN THE AFTERNOON. WILL HAVE WEAK CONVERGENCE ALONG THE
LAKE BREEZE FOR A FOCUS MECHANISM SO LIKE HAVING A CHANCE OF SHOWERS
OVER NORTHERN WISCONSIN FOR THE AFTERNOON. WARMED HIGHS UP A COUPLE
DEGREES AND WENT MID 70S TO LOW 80S.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. OTHER THAN TIMING
OF THE COLD FRONT LATE WEDNESDAY NIGHT OR THURSDAY THE MEDIUM
RANGE MODELS ARE IN PRETTY GOOD AGREEMENT INTO EARLY NEXT WEEK.
WEAK UPPER RIDGING SHOULD PROVIDE DRY WEATHER TUESDAY NIGHT AND
WEDNESDAY. UPPER DIFFLUENCE INCREASES WEDNESDAY NIGHT AS THE UPPER
TOUGH APPROACHES AND LOW LEVEL MOISTURE INCREASES AS WELL. SHOULD
GET A GOOD AREA OF SHOWERS AND THUNDERSTORMS MOVING INTO THE
WESTERN PART OF THE FORECAST AREA LATE WEDNESDAY NIGHT AND ACROSS
THE EAST THURSDAY MORNING. TIMING OF THE FRONT IS NOT IDEAL FOR
SEVERE THUNDERSTORMS SO THINK THAT THE SEVERE THREAT IS LOW.
UPPER FLOW BECOMES NORTHWEST FRIDAY AND SATURDAY AND A LARGE
SURFACE HIGH DROPS IN FROM THE NORTHERN PLAINS. WHILE IT SHOULD BE
GENERALLY DRY THERE IS A SMALL CHANCE OF MAINLY AFTERNOON SHOWERS
ACROSS THE NORTH IN THE COLD AND CYCLONIC FLOW. SURFACE HIGH
SHOULD BE RIGHT OVER THE AREA FRIDAY NIGHT AND WOULD NOT BE
SURPRISED TO SEE SOME FROST IN THE FAR NORTH.
&&
.AVIATION...ISOLD/SCT SHRA/TSRA ASSOCIATED WITH A COLD FRONT AND
UPPER LEVEL DISTURBANCE...WILL DISSIPATE RAPIDLY EARLY THIS EVG.
HAVE ADDED VCSH AT AUW/CWA/GRB THROUGH 02Z TO COVER THE LINGERING
ACTIVITY. CLEARING SKIES AND LIGHT WINDS WILL ALLOW PATCHY FOG TO
DEVELOP LATE TONIGHT...WITH LOCAL VLIFR VSBYS/CIGS POSSIBLE IN
AREAS THAT RECEIVED RAINFALL TODAY. HAVE ADDED A TEMPO GROUP FOR
1/2SM/VV002 AT RHI. ANY FOG THAT DEVELOPS SHOULD MIX OUT EARLY
TUESDAY MORNING...FOLLOWED BY SCT CUMULUS CLOUDS DEVELOPING IN
THE LATE MORNING AND AFTERNOON.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
259 PM CDT SUN AUG 12 2012
.SHORT TERM...TONIGHT AND MONDAY
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SHORTWAVE
TROUGHING MOVING EAST OVER IOWA AND MINNESOTA AND SURFACE LOW
PRESSURE CENTERED OVER NE KANSAS EARLY THIS AFTERNOON. ARCING BAND
OF PRECIP STRETCHING FROM SOUTHERN MINNESOTA TO WESTERN ILLINOIS HAS
GENERALLY BEEN DECAYING AS IT MOVES INTO DRIER AIR OVER WISCONSIN.
A SECONDARY AND MORE POTENT BAND IS MOVING NE OVER NORTHEAST IOWA
WHILE ANOTHER AREA OF PRECIP EXISTS OVER EASTERN NORTH DAKOTA WITHIN
THE COMMA HEAD OF THE SHORTWAVE AND ALONG A CANADIAN COOL FRONT. AS
THE SHORTWAVE ENERGY MOVES EAST OVER THE STATE...PRECIP CHANCES ARE
THE MAIN FORECAST CONCERNS IN THE SHORT TERM.
TONIGHT...SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL MOVE EAST
INTO THE STATE OF WISCONSIN TONIGHT. ASSOCIATED ELONGATED SURFACE
LOW WILL ALSO MOVE EAST INTO ILLINOIS. THE LATEST NAM AND ECMWF
SHOW 300K ISENTROPIC ASCENT AND FGEN WILL REMAIN OVER NORTHERN
ILLINOIS AND SOUTHERN WISCONSIN TONIGHT...WHERE THE LOW LEVEL
MOISTURE WILL ALSO BE THE MOST ABUNDANT. PROGGED SOUNDINGS AND
UPSTREAM OBS CONTINUE TO SHOW DRY WEDGES BELOW 700MB WHERE THE
ATMOSPHERE STRUGGLES TO SATURATE BELOW 10KFT. WILL STILL HAVE THE
MID-LEVEL WAVE MOVE OVERHEAD THOUGH...SO SPRINKLES OR LIGHT SHOWERS
CANNOT BE RULED OUT. BUT WILL PLACE THE HIGHEST PROBABILITY OF
SHOWERS OVER CENTRAL AND EAST-CENTRAL WISCONSIN...THOUGH THE
PROBABILITY WILL ONLY BE IN THE LOW CHANCE RANGE. A MOSTLY CLOUDY
NIGHT WITH LOWS IN THE MID 50S TO LOW 60S.
MONDAY...THE SHORTWAVE TROUGH WILL SLOWLY MOVE ACROSS CENTRAL AND
EASTERN WISCONSIN IN THE MORNING AND EASTERN WISCONSIN AND LAKE
MICHIGAN IN THE AFTERNOON. NOT QUITE AS BULLISH IN QPF AS THE SREF
OR THE GFS SINCE THINK THAT LOW LEVEL FORCING WILL RESIDE FARTHER
SOUTH. BUT STILL LOOKS LIKE THE BEST CHANCES OF PRECIP WILL OCCUR
IN THE MORNING WHEN EAST-CENTRAL WISCONSIN WILL BE ON THE NORTHERN
PERIPHERY OF THE DEEPER MOISTURE...AND THE COMMA HEAD OF THE
SHORTWAVE MOVES OVER NORTH-CENTRAL WISCONSIN. SOME INTERACTION WITH
DAYTIME INSTABILITY APPEARS POSSIBLE AS ML CAPES UP TO 400 J/KG WILL
BE POSSIBLE BY MIDDAY. WILL KEEP A CHANCE IN THE AFTERNOON TO
ACCOUNT FOR ANY DIURNAL INSTABILITY ACTIVITY. PLENTY OF CLOUD COVER
WILL KEEP HIGHS IN THE LOW TO MID 70S.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. UPPER TROUGH WILL
EXIT THE AREA MONDAY NIGHT AND SCATTERED SHOWERS WILL END. THEN
MAINLY DRY NORTHWEST UPPER FLOW EXPECTED TUESDAY THROUGH
WEDNESDAY. THERE COULD BE ISOLATED OR WIDELY SCATTERED SHOWERS
TUESDAY AFTERNOON BUT LEFT THEM OUT OF THE FORECAST FOR NOW. A
SIGNIFICANT UPPER TROUGH WILL APPROACH THE REGION WEDNESDAY NIGHT
AND THURSDAY. THERE CONTINUES TO BE TIMING DIFFERENCES BETWEEN THE
MEDIUM RANGE MODELS SO DID NOT GO WITH LIKELY PROBABILITIES OF
PRECIPITATION AS THERE IS UNCERTAINTY AS TO WHICH PERIOD(S) RAIN
WILL FALL. EITHER WAY IT WILL BE MILDER AND A LITTLE MORE HUMID
WEDNESDAY AS WINDS BECOME SOUTH AND MOISTURE INCREASES. THE UPPER
TROUGH REALLY ESTABLISHES ITSELF ACROSS THE GREAT LAKES FRIDAY
THROUGH SUNDAY. WE MAY SEE THE FIRST PERIOD OF COOLER THAN NORMAL
WEATHER THIS SUMMER THAT LASTS MORE THAN A DAY OR TWO. FROST LOOKS
POSSIBLE FRIDAY NIGHT IN NORTHERN WISCONSIN WITH BIG SURFACE HIGH
OVERHEAD AND LOW DEW POINTS. MENTIONED THIS POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION...A WEAK STORM SYSTEM WILL PASS ACROSS THE STATE OVER THE
TAF PERIOD. THE BULK OF THE PRECIPITATION WILL SLIDE BY TO THE
SOUTH...BUT THERE IS A CHANCE THAT A FEW SHOWERS WILL MOVE INTO EAST
CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT INTO MONDAY
MORNING. WILL SHOW VFR CONDITIONS THROUGH THE TAF PERIOD...AS CIGS
AND VSBYS ARE MOSTLY VFR UPSTREAM.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1103 PM MDT MON AUG 13 2012
.AVIATION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
ACROSS SOUTHERN PORTIONS OF SOUTH CENTRAL AND SOUTHEAST
COLORADO...WITH ISOLATED -TSRA MOST LIKELY TO AFFECT KALS THROUGH
08Z. BRIEF VFR CIGS/VIS IN LIGHT RAIN ALONG WITH WIND GUSTS TO 20
KTS WILL BE POSSIBLE WITH THUNDERSTORMS. KPUB AND KCOS WILL LIKELY
REMAIN DRY WITH VFR CIGS POSSIBLE AT TIMES...ESPECIALLY AT KPUB AS
MID CLOUD DECK REMAINS OVER THE AREA. SKIES WILL GRADUALLY CLEAR
TOWARDS MORNING. MUCH LESS WIDESPREAD -TSRA ACTIVITY IS EXPECTED
FOR TUESDAY...WITH ONLY ISOLATED -TSRA POSSIBLE AT KCOS AND KALS.
PROBABILITY LOOKS TOO LOW TO WARRANT INCLUSION IN TAF SITES AT
THIS TIME. -KT
&&
.PREV DISCUSSION... /ISSUED 318 PM MDT MON AUG 13 2012/
SHORT TERM...
(TONIGHT AND TOMORROW)
..SCATTERED STORMS FOR EVERYONE NEXT 6-9 HOURS OR SO...
CURRENTLY...
WATER VAPOR AT 2 PM SHOWS A HEALTHY DISTURBANCE UP IN WYOMING AND IT
WAS MOVING EAST SOUTHEAST TOWARDS THE REGION. A RATHER LARGE AREA OF
RAIN WAS NOTED OVER THE GENERAL NW SXTNS OF THE STATE OF CO...WITH
QUITE A FEW SHOWER SURROUNDING THIS AREA OF RAIN. A COUPLE OF
VORTICES WERE IMPLIED IN THE RAIN SHIELD (ORIENTATION OF CURVED
RAINSHIELD ON RADAR IMGY)...WITH ONE NW OF LARAMIE AND ANOTHER
ENTERING NW CO.
REST OF TODAY AND INTO TONIGHT...
SHOWERS AND STORMS WILL CONTINUE TO INCREASE IN COVERAGE OVER THE
REGION...AND THERE IS A PRETTY GOOD CHANCE NEARLY ALL OF US WILL SEE
SOME RAIN DURING THE NEXT 9 HOURS OR SO. PRECIP WAS ALREADY
DEVELOPING ON THE PLAINS AS I WRITE (2 PM) AND HRRR FCST THIS TO
EXPAND AND MOVE TO THE EAST-SOUTHEAST. EVEN GFS HAS A LARGE BULLSEYE
OF PRECIP OVER THE FAR SE PLAINS LATER TODAY. AS FOR THE BURN
SCAR...LATEST HI RES GUIDANCE SHOWS THE BEST CHANCE BETWEEN 3 AND 5
PM. LOCALLY HEAVY RAIN COULD OCCUR BUT I AM NOT ALL THAT CONFIDENT
AS IT MAY BE TOO STABLE FOR ANY HEAVIER RAIN OVER THE SCAR...HOWEVER
I AM PRETTY CERTAIN THEY WILL GET MORE PRECIP TODAY. PRECIP OVER THE
REST OF THE MTNS WILL CONTINUE TO BLOSSOM AS THE AFTERNOON
PROGRESSES.
SHOWERS AND STORMS WILL BE ONGOING ACROSS THE PLAINS THIS EVENING.
ACTIVITY OVER THE MTNS WILL STILL BE ONGOING...BUT WILL BE ON A
GRADUAL DOWNWARD TREND AS THE EVENING PROGRESSES. I WOULD EXPECT BY
MID EVENING THE HEAVIEST STORMS WILL BE OVER THE EASTERN
PLAINS...ESPECIALLY THE FAR E PLAINS. A FEW STRONGER STORMS WILL BE
POSSIBLE BUT WILL ONLY BE MARGINALLY SEVERE AT BEST GIVEN THE
LIMITED CAPE/SHEAR FIELDS CURRENTLY IN PLACE.
BY MIDNIGHT...ISOLATED PRECIP MAY BE OVER THE MTNS WITH PRECIP OVER
THE FAR E PLAIN MOVING OUT OF THE STATE.
TOMORROW...
RATHER STABLE AIRMASS WILL LIKELY BE OVER THE PLAINS AND DO NOT
EXPECT ANY PRECIP. THE ONLY EXCEPTION MAY BE THAT PART OF THE PLAINS
ABOVE 6000 FEET WHICH MAY SEE A SHOWER LATE IN THE DAY. THE MTNS
WILL CONTINUE TO SEE SCTD COVERAGE..ESPECIALLY ALONG THE CONTDVD. I
DID KNOCK DOWN TEMPS A FEW DEGREES AS IT WILL LIKELY BE A BIT COOLER
TOMORROW THAN EARLIER ADVERTISED.
LONG TERM...
(TUESDAY NIGHT THROUGH MONDAY)
TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON...AS THE UPPER WAVE
DEPARTS AND THE RIDGE CONTINUES TO BREAK DOWN...SUBSIDENCE SHOULD
RESTRICT CONVECTION TO THE MTS THROUGH THE EVE...THEN THE TYPICAL
ISOLATED TO LOW SCATTERED CONVECTION FOR THE MTS WED AFTN. A WARM
AND BREEZY DAY IS ON TAP FOR WED...AHEAD OF THE NEXT INCOMING SFC
FRONT.
WEDNESDAY NIGHT THROUGH FRIDAY...MODELS INDICATE A RATHER STRONG
SHORTWAVE DROPS DOWN OUT OF CANADA AND ACROSS THE NORTHERN PLAINS ON
WED...PUSHING A SFC FRONT DOWN INTO COLORADO WED EVE. NAM MODEL
SHOWS A PRE-FRONTAL NORTHERLY PUSH THROUGH THE DAY WED...WITH THE
TRUE SFC FRONT CROSSING THE PALMER DVD RIGHT BETWEEN 00Z AND 06Z.
SO...NORTHERLY WINDS LATE WED NIGHT INTO THU MORNING...WITH WINDS
SWINGING AROUND TO THE EAST BY THU AFTN. PCPN SHOULD BE FAIRLY
WIDESPREAD LATE WED NIGHT AND LINGER INTO THE EARLY MORNING HRS OF
THU...THEN FIRE UP AGAIN QUICKLY ON THU WITH UPSLOPE SHOVING THE
MOISTURE UP AGAINST THE SOUTHERN FRONT RANGE. PCPN WILL TAPPER OFF
FROM N TO S THU EVE...THEN A LITTLE LESS COVERAGE IS THEN FORECAST
FOR FRI. MAX TEMPS ON THU ARE CURRENTLY FORECAST TO WARM INTO THE
70S TO NEAR 80 F FOR THE PLAINS...BUT WITH THE EXPECTED CLOUD COVER
THIS MAY BE SLIGHTLY TOO WARM...AND WILL HAVE TO REVISIT MAX TEMP
GRIDS AGAIN OVER THE NEXT FEW MODEL RUNS. THE COOL TEMPS SHOULD
CARRY OVER INTO FRI AS THE LLVL COOL AIR AND MOISTURE GRADUALLY
ERODES.
SATURDAY THROUGH MONDAY...UPPER RIDGE STRENGTHENS OVER THE WESTERN
US FOR THE WEEKEND...WITH CONVECTIVE ACTIVITY SLIPPING BACK INTO A
DIURNAL PATTERN WITH MORE ISOLATED COVERAGE TIED TO THE HIGHER
TERRAIN. GFS MODEL IS INDICATING A LOT MORE POSSIBLE PCPN OVER THE
PLAINS...WHICH IS LIKELY A RESULT OF THE RIDGE BREAKING DOWN FASTER
THAN WHAT THE ECMWF SHOWS...SO WILL MAINTAIN THE FORECAST OF DIURNAL
MT CONVECTION AND MAX TEMPS CLIMBING BACK INTO THE 90S FOR THE
PLAINS AND 80S FOR THE HIGH VALLEYS. 27
AVIATION...
ALL TAFS SITES WILL SEE STORMS TODAY. A FEW SHOWERS HAVE ALREADY
MOVED ACROSS KALS AND KCOS AS PER RADAR IMGY. WITH THE VORT MAX
MOVING ACROSS THE AREA LATER TODAY AND EARLY THIS EVENING SCATTERED
STORMS WILL MOVE ACROSS THE TAF SITES...WITH THE BEST CHANCE BETWEEN
3 AND 7 PM AT KCOS AND 3 AND 8 PM ACROSS KPUB. SHOWERS WILL MOVE
ACROSS KALS BETWEEN NOW AND 8 PM THIS EVENING. CIGS SHOULD REMAIN
ABOVE MVFR BUT WE MAY SEE BRIEF HVY RAINS WHICH WILL BRING MVFR
CONDITIONS TO THE TAF SITES.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31/44
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
509 AM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT
STRETCHES FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION...
HAS SPARKED CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND
WEST CENTRAL GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS
HOLD THIS CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS
INTO THE ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER...
CANNOT RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING
HOURS. EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND
SOUTH BUT WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT...
CURRENTLY ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER
THIS AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND
OF CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
AVIATION...
09Z UPDATE...
AN UPPER DISTURBANCE HAS SPARKED SCATTERED CONVECTION THAT WILL PUSH
ACROSS THE ATLANTA TAF SITES EARLY THIS MORNING. EXPECT A BRIEF
THREAT OF -TSRA THROUGH 11-12Z...WITH PREVAILING -RA CONTINUING
THROUGH 14-15Z. EXPECT TO SEE BRIEF MVFR CIGS THIS MORNING WITH THE
HEAVIER CONVECTION... BUT MID LEVEL VFR CIGS SHOULD PREVAIL BY
MID-LATE MORNING. A FRONTAL BOUNDARY WILL PUSH INTO FAR NW GA LATER
THIS AFTERNOON WITH SCATTERED CONVECTION EXPECTED TO DEVELOP OUT
AHEAD DURING MAX HEATING. MODELS AGREE THIS WILL BRING ANOTHER
THREAT OF TSTMS TO THE ATLANTA TAF SITES BY LATE AFTERNOON OR EARLY
EVENING. OTHERWISE...LIGHT SW WINDS THIS MORNING WILL INCREASE TO
AROUND 8-10KTS BY 15-16Z...AND BECOME MORE WESTERLY BY THIS EVENING.
//ATL CONFIDENCE...09Z UPDATE...
MEDIUM TO HIGH ON ALL ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....20
AVIATION...39
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
324 AM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT STRETCHES
FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION... HAS SPARKED
CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND WEST CENTRAL
GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS HOLD THIS
CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS INTO THE
ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER... CANNOT
RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING HOURS.
EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND SOUTH BUT
WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT... CURRENTLY
ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER THIS
AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND OF
CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
AVIATION...
06Z UPDATE...
INITIAL CONCERN IS SCATTERED CONVECTION OVER AL EARLY THIS MORNING.
TIMING TOOL SUGGEST AT LEAST -SHRA COULD MOVE INTO THE ATLANTA AREA
BY 10-12Z THIS MORNING. THE UPPER SHORT WAVE IS WEAKENING...BUT IS
EMBEDDED IN A LONG WAVE TROUGH THAT COULD SUPPORT ON-GOING
CONVECTION AS IT MOVES EASTWARD. HAVE ELECTED TO SHOW MID LEVEL CIGS
ASSOCIATED WITH THIS ACTIVITY FOR NOW AS SOME MODELS INDICATE IT MAY
SPLIT NORTH AND SOUTH OF ATLANTA AREA. WILL WATCH THIS ACTIVITY FOR
THE NEXT FEW HOURS... THEN AMEND AS NECESSARY IF CONVECTION HOLDS
TOGETHER AND ENTERS GA LATER THIS MORNING. OTHERWISE... COULD SEE
SOME BRIEF MVFR CIGS DEVELOP THIS MORNING BUT THINK THE MID LEVEL
CIGS SPREADING IN FROM THE WEST WILL DOMINATE THIS MORNING. A
FRONTAL BOUNDARY WILL PUSH INTO FAR NW GA LATER THIS AFTERNOON WITH
SCATTERED CONVECTION EXPECTED OUT AHEAD DURING MAX HEATING. WILL
FOCUS ON THIS CONVECTION FOR NOW. LIGHT WINDS WILL BECOME SW 8-10KTS
BY 15-16Z TODAY.
//ATL CONFIDENCE...06Z UPDATE...
LOW TO MEDIUM ON CONVECTION OR MVFR CIGS THIS MORNING. MEDIUM TO
HIGH ON REMAINING ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....20
AVIATION...39
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
156 AM EDT TUE AUG 14 2012
.UPDATE...
/ISSUED AT 940 PM EDT MON AUG 13 2012/
HAVE TWEAKED POPS AGAIN...KEEPING CHANCE OR SLIGHT CHANCE
OVER MUCH OF THE CWA EXCEPT EAST CENTRAL. WATCHING THUNDERSTORMS IN
MISSISSIPPI AND MAY HAVE TO ADJUST POPS AGAIN LATER. WITH RAIN
COOLED AIR ACROSS THE NORTHWEST...HOURLY TEMPERATURES HAVE FALLEN
MORE RAPIDLY AND HAVE TRIED TO ADJUST FOR THAT IN THE GRIDS.
41
.PREVIOUS UPDATE...
/ISSUED AT 800 PM EDT MON AUG 13 2012/
DIFFICULT FORECAST FOR TONIGHT...WITH NONE OF THE MODELS REALLY
HAVING A GOOD HANDLE ON THE CURRENT SHOWER AND THUNDERSTORM ACTIVITY.
HAVE SIGNIFICANTLY UPDATED POPS AND WEATHER GRIDS TO ACCOUNT FOR
CURRENT CONVECTION ASSOCIATED WITH MCS THAT MOVED EASTWARD OUT OF
TN/AL THIS AFTERNOON. LATEST LAPS SHOWING BEST INSTABILITY ALONG THE
GA/AL LINE...WITH AREAS FURTHER EAST FAR MORE STABLE. IN
GENERAL...EXPECT AN OVERALL WEAKENING TREND AS THIS LARGE AREA OF
PRECIPITATION CONTINUES TO MOVE EASTWARD.
WILL BE MAKING PERIODIC UPDATES TO THE FORECAST AS NECESSARY AS
THIS EVENT CONTINUES TO UNFOLD. HAVE GONE AHEAD AND CANCELLED THE
SVR WATCH FOR THE FAR NORTHEAST PORTION OF THE STATE.
31
&&
.PREV DISCUSSION... /ISSUED 308 PM EDT MON AUG 13 2012/
..SEVERE STORMS EXPECTED THROUGH THIS EVENING EXTREME NW GEORGIA...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ALL EYES ON MCS OVER TENNESSEE AND ALABAMA WHICH CONTINUES TO MAKE
STEADY PROGRESS TO THE EAST. NOW HAVE A WATCH UP FOR THE EXTREME
NW CORNER OF THE FORECAST AREA WHERE THERE IS IRONICALLY LITTLE TO
NO INSTABILITY AT THIS TIME. SYSTEM HAS HOWEVER BEEN ABLE TO BRING
ALONG ITS OWN ENHANCED MOISTURE AND INSTABILITY ALTHOUGH ITS
ABILITY TO DO SO AS IT APPROACHES THE FORECAST AREA REMAINS IN
QUESTION. RAP SHORT TERM GUIDANCE DOES SHOW INCREASED INSTABILITY
WITHIN THE NEXT 2 HOURS PUSHING INTO THE NW ZONES BUT ONLY ON THE
ORDER OF 1500 TO 2000 J/KG...MUCH LESS THAN UPSTREAM VALUES WE HAVE
SEEN. SO IN SHORT...EXPECTING SVR POTENTIAL TO INCREASE FOR THE
EXTREME NW AND WESTERN TIER OVER THE NEXT SEVERAL HOURS BUT TRENDS
IN INSTABILITY SUGGEST A LIMITED TIMEFRAME FOR CONVECTIVE
POTENTIAL. ALSO WATCHING DEVELOPING AREA OF DCAPE IN EXCESS OF
1000 J/KG WHICH COULD ALLOW FOR ISOLATED SVR OUTSIDE OF CURRENT
WATCH AREA FROM COLUMBUS UP TO LA GRANGE.
QUESTIONS ALSO SURROUND HOW FAR ACTUAL LINE OF SHOWERS AND STORMS
MAKES IT TO THE EAST. AS MENTIONED...EXPECTING A SHARP INSTABILITY
GRADIENT AND MOMENTUM LOOKS TO ONLY TAKE THIS SYSTEM SO FAR. HRRR
IS DIMINISHING LINE AND THEN GENERATES NEW CONVECTION ALONG ACTUAL
FRONT INTO THE OVERNIGHT HOURS. GIVEN CURRENT TRENDS...WILL EXPAND
POP COVERAGE SLIGHTLY EASTWARD BUT ONLY CARRY LOW END CHANCE POPS
INTO THE OVERNIGHT PERIOD FOR THE ATLANTA METRO AND POINTS NORTH
AND WEST.
BY 12Z...FRONT WILL SAG INTO NORTH GEORGIA WITH DRIER AIR
BEGINNING TO FILTER IN. WILL BE IN LARGE SCALE TROUGH PATTERN BUT
NO NOTABLE SHORTWAVES EMBEDDED IN FLOW UNTIL 00Z. THIS COULD
ENHANCE POPS FIELD BUT PRIMARILY OVER THE SOUTHERN TIER WHERE I
HAVE INCLUDED LIKELY POPS.
DEESE
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO SIGNIFICANT CHANGES PLANNED.
BDL
MEDIUM RANGE MODELS REMAIN CONSISTENT THROUGH THE EXTENDED
FORECAST PERIOD KEEPING THE EASTERN U.S. UNDER PERSISTENT LONG
WAVE TROUGHING. ALTHOUGH THE LARGE SCALE PATTERN REMAINS FAIRLY
STATIC...THE SMALLER SCALE REMAINS QUITE ACTIVE AS SHORT WAVES
SWING THROUGH THE TROUGH DIGGING OUT OF THE NORTHERN PLAINS INTO
THE OHIO VALLEY. THIS PATTERN KEEPS THE BEST UPPER DYNAMICS NORTH
OF THE REGION...BUT MANAGES TO DRIVE A SERIES OF ASSOCIATED
SURFACE FRONTS THROUGH THE STATE. FIRST SYSTEM IS EXITING AS WE
HEAD INTO THE EXTENDED PERIOD SO ANOTHER SHOT OF MILDER AND FAIRLY
DRY AIR SETTLES IN FOR THE MIDDLE OF THE WEEK. NEXT SYSTEM IS
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND. THIS
CORRESPONDS WELL WITH PREVIOUS MODEL RUNS SO THERE ARE NO
SIGNIFICANT CHANGES TO THE PREVIOUS EXTENDED FORECAST THEMES.
20
&&
.AVIATION...
06Z UPDATE...
INITIAL CONCERN IS SCATTERED CONVECTION OVER AL EARLY THIS MORNING.
TIMING TOOL SUGGEST AT LEAST -SHRA COULD MOVE INTO THE ATLANTA AREA
BY 10-12Z THIS MORNING. THE UPPER SHORT WAVE IS WEAKENING...BUT IS
EMBEDDED IN A LONG WAVE TROUGH THAT COULD SUPPORT ON-GOING
CONVECTION AS IT MOVES EASTWARD. HAVE ELECTED TO SHOW MID LEVEL CIGS
ASSOCIATED WITH THIS ACTIVITY FOR NOW AS SOME MODELS INDICATE IT MAY
SPLIT NORTH AND SOUTH OF ATLANTA AREA. WILL WATCH THIS ACTIVITY FOR
THE NEXT FEW HOURS... THEN AMEND AS NECESSARY IF CONVECTION HOLDS
TOGETHER AND ENTERS GA LATER THIS MORNING. OTHERWISE... COULD SEE
SOME BRIEF MVFR CIGS DEVELOP THIS MORNING BUT THINK THE MID LEVEL
CIGS SPREADING IN FROM THE WEST WILL DOMINATE THIS MORNING. A
FRONTAL BOUNDARY WILL PUSH INTO FAR NW GA LATER THIS AFTERNOON WITH
SCATTERED CONVECTION EXPECTED OUT AHEAD DURING MAX HEATING. WILL
FOCUS ON THIS CONVECTION FOR NOW. LIGHT WINDS WILL BECOME SW 8-10KTS
BY 15-16Z TODAY.
//ATL CONFIDENCE...06Z UPDATE...
LOW TO MEDIUM ON CONVECTION OR MVFR CIGS THIS MORNING. MEDIUM TO
HIGH ON REMAINING ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 90 69 91 / 20 40 20 10
ATLANTA 70 87 71 88 / 60 30 20 10
BLAIRSVILLE 63 83 64 85 / 50 30 20 5
CARTERSVILLE 67 87 68 89 / 70 30 20 5
COLUMBUS 71 90 74 91 / 60 40 20 20
GAINESVILLE 67 87 69 88 / 50 30 20 10
MACON 67 91 72 91 / 20 50 30 20
ROME 67 87 68 89 / 50 30 20 5
PEACHTREE CITY 67 87 69 89 / 60 30 20 10
VIDALIA 70 92 75 92 / 10 60 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41/39
LONG TERM....31
AVIATION...39
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1139 PM CDT MON AUG 13 2012
.DISCUSSION...
ISSUED 850 PM CDT MON AUG 13 2012
CLEARING LINE HAS PUSHED TO ABOUT A MACOMB-PEORIA-LACON LINE AT
MID EVENING. MAIN QUESTION IS HOW MUCH FURTHER SOUTH THIS WILL
MAKE IT. HAVE BEEN SEEING SOME EVIDENCE THAT AREAS EAST OF I-39
ARE NOT CLEARING OUT QUITE AS FAST AS FURTHER SOUTHWEST...AND
AN AREA OF STRATUS BELOW 1000 FEET HAS BEEN DEVELOPING FROM
DECATUR TO PONTIAC. AWIPS TIME-OF-ARRIVAL TOOL AND RAP MODEL CLOUD
GUIDANCE HAS THE WESTERN CWA MOSTLY CLEAR BEFORE MIDNIGHT...BUT
THE RAP INDICATES THE CLOUDS ACROSS THE EAST WILL BE TOUGH TO
ERODE WITH A BOUNDARY STILL IN THE AREA. HAVE ADDED SOME MENTION
OF PATCHY FOG OVERNIGHT...ESPECIALLY IN AREAS THAT WILL SEE SOME
SUBSTANTIAL CLEARING AND LIGHTER WINDS.
UPDATED ZONES/GRIDS HAVE BEEN SENT.
GEELHART
&&
.AVIATION...
ISSUED 1137 PM CDT MON AUG 13 2012
CLEARING LINE ROUGHLY EXTENDS FROM KIJX-KPNT AT 04Z. EASTERN
FLANKS OF THE CLEARING HAVE NOT MADE ANY REAL PROGRESS AS OF
LATE...AND PLAN TO KEEP IFR/LIFR CONDITIONS AT KCMI/KDEC THROUGH
THE NIGHT. 500 FOOT STRATUS DECK BECOMING WIDESPREAD ACROSS EAST
CENTRAL ILLINOIS...WITH LATEST MODEL GUIDANCE SHOWING IT HANGING
ON THROUGH ABOUT 13Z. THINK THE CLOUDS AT KDEC/KCMI WILL KEEP THE
VISIBILITY FROM GETTING OUT OF HAND...BUT AREAS FURTHER NORTH THAT
HAVE CLEAR SKIES IMMINENT OR ONGOING WILL BE SUSCEPTIBLE TO SOME
AREAS OF FOG. HAVE ALREADY SEEN VISIBILITIES DOWN TO 1/4 MILE AT
TIMES AT KGBG AND KC75...AND FEEL THAT KBMI/KPIA WILL BE
VULNERABLE AS WELL. ONCE THE LOW CLOUDS AND FOG LIFT AROUND
13-15Z...VFR CONDITIONS WILL PREVAIL AT ALL SITES.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT MON AUG 13 2012
CLOUDY...COOL...AND SHOWERY WEATHER WILL CONTINUE THIS EVENING
BEFORE THE SURFACE LOW FINALLY DEPARTS INTO INDIANA. FOR TUESDAY
AND WEDNESDAY...SURFACE HIGH PRESSURE WILL KEEP THE WEATHER
QUIET...WITH MUCH WARMER TEMPS ON WEDNESDAY. THEN A COLD FRONT
WILL BRING SHOWERS AND STORMS BACK TO THE AREA THURSDAY AND
THURSDAY NIGHT...FOLLOWED BY A RETURN TO BELOW NORMAL TEMPS FOR
NEXT WEEKEND AND INTO NEXT WEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY.
INSTABILITY NEAR THE SURFACE LOW WILL ALLOW SHOWERS AND POSSIBLY A
FEW THUNDERSTORMS TO LINGER INTO THE EVENING...MAINLY EAST OF
I-55. THE LOW CENTER IS EXPECTED TO TRACK JUST SOUTH OF
SPRINGFIELD TO LAWRENCEVILLE. THE SPC DY1 OUTLOOK STILL INCLUDES
OUR FAR SOUTHEAST COUNTIES NEAR LWV...WHERE MU CAPES ARE NEAR 1000
J/KG AND EFFECTIVE SHEAR IS 25-30KT. BY MIDNIGHT...THE LOW SHOULD
BE INTO INDIANA...AND INTO KY BY 12Z TUES. WE KEPT SOME SLIGHT
CHANCE POPS AFTER MIDNIGHT EAST OF I-57.
TUESDAY WILL SEE HIGH PRESSURE ARRIVING...BUT THE TYPICALLY COOLER
AIR BEHIND THE LOW WILL BE SHORT LIVED AS 850MB TEMPS WARM FROM 12
TO 16C TUES AFTERNOON. THAT WARMING ALONG WITH INCREASING SUNSHINE
AS THE DAY PROGRESSES WILL HELP TEMPS WARM INTO THE LOW TO MID
80S. THAT WARMING TREND WILL INTENSIFY ON WEDNESDAY AS THE THERMAL
RIDGE PEAKS AHEAD OF THE APPROACHING COLD FRONT. HIGHS ON WED ARE
EXPECTED TO CLIMB ABOVE NORMAL IN THE UPPER 80S TO LOWER 90S.
A FEW SHOWERS MAY DEVELOP THURSDAY MORNING...BUT THE BULK OF THE
PRECIPITATION ACCUMULATION SHOULD COME THURS AFTERNOON AND
EVENING. THE NAM IS THE FAST OUTLIER WITH TIMING OF THE FRONT INTO
THE MID CWA BY 18Z...BUT WE DECIDED TO CONTINUE WITH THE CONSENSUS
SLOWER SOLUTION OF THE GFS/CANADIAN GEM/ECMWF. WE HAVE LIKELY POPS
IN THE NW HALF THURS AND THE SE HALF THURS NIGHT.
LONG TERM...FRIDAY THROUGH MONDAY.
A COOLER AIRMASS WILL SETTLE INTO THE UPPER MIDWEST FOR FRIDAY AND
LINGER THROUGH MONDAY...WITH BELOW NORMAL TEMPS ACROSS THE BOARD.
AS THE UPPER TROUGH AXIS MOVES ACROSS CENTRAL IL ON FRIDAY...WE
CANT RULE OUT A FEW SPRINKLES DEVELOPING IN THE STEEPER LAPSE
RATES. HOWEVER...WE KEPT THE FORECAST DRY FOR NOW. THE REMAINDER
OF THE WEEKEND AND INTO MONDAY IS FORECAST TO BE DRY BY THE ECMWF.
THE OVERLY MOIST GFS IS GENERATING DIURNAL SHOWERS EACH DAY OF THE
EXTENDED. NORTHWEST FLOW ALOFT MAY ALLOW FOR A STRAY SHORTWAVE AT
SOME POINT THIS WEEKEND...BUT CHANCES ARE LOW ENOUGH TO LEAVE OUT
TRYING TO PINPOINT TIMING THIS EARLY.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1145 PM MDT MON AUG 13 2012
.UPDATE...
ISSUED AT 1008 PM MDT MON AUG 13 2012
JUST COMPLETED ANOTHER UPDATE. CURRENT PRECIPITATION FORECAST IS
ON TRACK. DID NOT WANT TO MESS WITH EITHER HAVING A PREVAILING
THUNDERSTORM OR EMBEDDED THUNDERSTORM FORECAST CONSIDERING WHAT
IS GOING ON UPSTREAM PLUS THE STRENGTH OF THE LIFT COMING IN.
PRECIPITATION LOOKS TO BE DONE BY 12Z. HRRR/RUC/NAM HINTING AT
SOME PATCHY FOG IN THE WEST...ROUGHLY IN THE AREA THAT RECEIVED
THE RAINFALL THIS EVENING...FROM LATER TONIGHT INTO TOMORROW
MORNING. WILL DEPEND ON HOW MUCH CLEARING WE GET BUT THAT DOES
LOOK REASONABLE CONSIDERING THE TEMPERATURE/DEWPOINT SPREADS ARE
ALREADY NOT THAT FAR APART EVEN WITH THE CLOUD COVER. WILL INSERT
IT INTO THE GRIDS FROM 09Z TO 15Z.
HRRR IS DOING WELL ON THE DEWPOINTS AND CURRENT TEMPERATURES AND
WINDS. SO WILL USE TO ADJUST DEWPOINTS...WINDS AND MINS. ADJUSTED
MINS DOWN IN THE NORTHWEST HALF AND UP A LITTLE IN THE SOUTHEAST
PORTION WHERE MORE CLOUD COVER WILL BE.
UPDATE ISSUED AT 616 PM MDT MON AUG 13 2012
JUST COMPLETED AN UPDATE. SIGNIFICANTLY RAISED POPS IN THE
SOUTHWEST HALF OF THE AREA. SHORTWAVE TROUGH AND RIGHT REAR
QUADRANT OF JET ARE INCREASING THE COVERAGE OF STORMS FURTHER EAST
THAN WHAT WAS PREVIOUSLY DEPICTED. THE HRRR IS CATCHING THE HOURLY
TRENDS ON THE PRECIPITATION VERY WELL AND IS MIRRORED CLOSELY BY
THE 6 HOUR AMOUNTS SHOWN BY THE SREF AND ECMWF. THIS AREA MAKES
VERY GOOD SENSE CONSIDERING THE TRENDS AND THE LIFTING MECHANISMS.
SO FOLLOWED CLOSELY THOSE MODEL DEPICTIONS THROUGH THIS EVENING.
OTHERWISE...INCREASED CLOUD COVER SIGNIFICANTLY THROUGH THE
EVENING. WILL MONITOR TRENDS ON EVERYTHING ELSE THROUGH THE
EVENING. MESOSCALE AFFECTS WILL NO DOUBT WREAK HAVOC ON REMAINING
PARAMETERS THROUGH THE NIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 140 PM MDT MON AUG 13 2012
UPPER FLOW WILL BE NORTHWEST TONIGHT/TUESDAY. A SHORTWAVE WILL COME
THROUGH THE FLOW TONIGHT. SUBSIDENCE WILL FOLLOW BEHIND THE WAVE ON
TUESDAY. SURFACE HIGH PRESSURE WILL BE OVER THE AREA TONIGHT. LOW
PRESSURE WILL BE OVER EASTERN WYOMING/NORTHEAST COLORADO TUESDAY.
DYNAMICS FROM THE INCOMING SHORTWAVE TONIGHT ARE SHOWN TO SLIDE
SOUTHEAST FROM EASTERN COLORADO INTO THE SOUTHERN FA. THIS IS WHERE
THE BEST MOISTURE IS AS WELL. PLAN TO GO WITH CHANCE POPS FOR THIS
AREA AND SLIGHT CHANCE POPS WHERE THERE IS LESS MOISTURE AND
FORCING. SUBSIDENCE WILL KEEP POPS NIL TUESDAY.
MIN TEMPERATURES TONIGHT WILL BE WARMER THAN LAST NIGHT AS COOLER
TEMPERATURES HAVE MOVED PAST THE FA AND SOUTH WINDS WILL MAINTAIN
GOOD MIXING OVERNIGHT. EXPECT READINGS IN THE UPPER 50S/LOWER 60S.
MAX TEMPERATURES TUESDAY WILL RISE INTO THE LOWER 90S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 250 PM MDT MON AUG 13 2012
THE FIRST SIGNIFICANT WEATHER FEATURE TO IMPACT THE AREA DURING
THIS PERIOD WILL BE A STRONG UPPER SHORT WAVE TROUGH NOW OVER
BRITISH COLUMBIA AS SEEN IN WATER VAPOR IMAGERY. THIS TROUGH WILL
MOVE SOUTHEAST AND SWEEP ACROSS THE C-N PLAINS WED-WED NIGHT. AT
THE SURFACE A STRONG COLD FRONT WILL MOVE RAPIDLY SOUTH ACROSS THE
FORECAST AREA WEDNESDAY EVENING AND WILL CLEAR THE AREA LATE
WEDNESDAY NIGHT. THESE FEATURES WILL GIVE AN OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS MAINLY WEDNESDAY NIGHT. MUCH COLDER AIR
WILL SETTLE INTO THE REGION FOR THURSDAY AND FRIDAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S.
BOTH THE EC AND GFS SUGGEST A MODERATELY STRONG NORTHWEST FLOW
ALOFT FOR THE REMAINDER OF THE WEEK AND THROUGH THE WEEKEND. THE
EC IS MOSTLY DRY WITH THIS PATTERN BUT THE GFS SUGGESTS THE
POTENTIAL FOR SEVERAL EPISODES OF PRECIPITATION. BOTH MODELS HINT
AT SEVERAL WEAK...FAST-MOVING SHORT WAVE TROUGHS SLIDING SOUTHEAST
THROUGH THE FLOW BUT TIMING WILL BE DIFFICULT. LOW POPS ARE
INCLUDED IN THE EXTENDED FORECAST AS A RESULT. ANY CONVECTION
WHICH INITIATES ON THE CHEYENNE RIDGE WOULD MOVE INTO THE
AREA...AIDED BY SOUTHEAST SURFACE FLOW WHICH WILL ENHANCE STORM
INFLOW TO KEEP CONVECTION GOING FOR A FEW HOURS BEFORE
DISSIPATION.
TEMPERATURES OVER THE WEEKEND WILL RETURN TO CLOSER TO NORMAL
VALUES BUT THE EXTREME HEAT HAS ABATED FOR AT LEAST THE NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1142 PM MDT MON AUG 13 2012
LINGERING LIGHT RAIN SHOWERS WILL BE AT OR NEAR BOTH SITES FOR THE
NEXT HOUR OR TWO. ONCE THE SHOWERS END AND SOME CLEARING OCCURS...MODELS
HAVE COME MORE INTO AGREEMENT OF BRINGING MVFR CEILINGS AND VISIBILITIES
INTO BOTH SITES WITH THE WORST CONDITIONS AT KGLD. CLEARING DOES
NOT OCCUR UNTIL MID TO LATE MORNING. ONCE THE CLEARING OCCURS...GUSTY
SOUTHERLY WINDS WILL BEGIN AND CONTINUE THROUGH MOST OF THE REST
OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...FS
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1018 PM MDT MON AUG 13 2012
.UPDATE...
ISSUED AT 1008 PM MDT MON AUG 13 2012
JUST COMPLETED ANOTHER UPDATE. CURRENT PRECIPITATION FORECAST IS
ON TRACK. DID NOT WANT TO MESS WITH EITHER HAVING A PREVAILING
THUNDERSTORM OR EMBEDDED THUNDERSTORM FORECAST CONSIDERING WHAT
IS GOING ON UPSTREAM PLUS THE STRENGTH OF THE LIFT COMING IN.
PRECIPITATION LOOKS TO BE DONE BY 12Z. HRRR/RUC/NAM HINTING AT
SOME PATCHY FOG IN THE WEST...ROUGHLY IN THE AREA THAT RECEIVED
THE RAINFALL THIS EVENING...FROM LATER TONIGHT INTO TOMORROW
MORNING. WILL DEPEND ON HOW MUCH CLEARING WE GET BUT THAT DOES
LOOK REASONABLE CONSIDERING THE TEMPERATURE/DEWPOINT SPREADS ARE
ALREADY NOT THAT FAR APART EVEN WITH THE CLOUD COVER. WILL INSERT
IT INTO THE GRIDS FROM 09Z TO 15Z.
HRRR IS DOING WELL ON THE DEWPOINTS AND CURRENT TEMPERATURES AND
WINDS. SO WILL USE TO ADJUST DEWPOINTS...WINDS AND MINS. ADJUSTED
MINS DOWN IN THE NORTHWEST HALF AND UP A LITTLE IN THE SOUTHEAST
PORTION WHERE MORE CLOUD COVER WILL BE.
UPDATE ISSUED AT 616 PM MDT MON AUG 13 2012
JUST COMPLETED AN UPDATE. SIGNIFICANTLY RAISED POPS IN THE
SOUTHWEST HALF OF THE AREA. SHORTWAVE TROUGH AND RIGHT REAR
QUADRANT OF JET ARE INCREASING THE COVERAGE OF STORMS FURTHER EAST
THAN WHAT WAS PREVIOUSLY DEPICTED. THE HRRR IS CATCHING THE HOURLY
TRENDS ON THE PRECIPITATION VERY WELL AND IS MIRRORED CLOSELY BY
THE 6 HOUR AMOUNTS SHOWN BY THE SREF AND ECMWF. THIS AREA MAKES
VERY GOOD SENSE CONSIDERING THE TRENDS AND THE LIFTING MECHANISMS.
SO FOLLOWED CLOSELY THOSE MODEL DEPICTIONS THROUGH THIS EVENING.
OTHERWISE...INCREASED CLOUD COVER SIGNIFICANTLY THROUGH THE
EVENING. WILL MONITOR TRENDS ON EVERYTHING ELSE THROUGH THE
EVENING. MESOSCALE AFFECTS WILL NO DOUBT WREAK HAVOC ON REMAINING
PARAMETERS THROUGH THE NIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 140 PM MDT MON AUG 13 2012
UPPER FLOW WILL BE NORTHWEST TONIGHT/TUESDAY. A SHORTWAVE WILL COME
THROUGH THE FLOW TONIGHT. SUBSIDENCE WILL FOLLOW BEHIND THE WAVE ON
TUESDAY. SURFACE HIGH PRESSURE WILL BE OVER THE AREA TONIGHT. LOW
PRESSURE WILL BE OVER EASTERN WYOMING/NORTHEAST COLORADO TUESDAY.
DYNAMICS FROM THE INCOMING SHORTWAVE TONIGHT ARE SHOWN TO SLIDE
SOUTHEAST FROM EASTERN COLORADO INTO THE SOUTHERN FA. THIS IS WHERE
THE BEST MOISTURE IS AS WELL. PLAN TO GO WITH CHANCE POPS FOR THIS
AREA AND SLIGHT CHANCE POPS WHERE THERE IS LESS MOISTURE AND
FORCING. SUBSIDENCE WILL KEEP POPS NIL TUESDAY.
MIN TEMPERATURES TONIGHT WILL BE WARMER THAN LAST NIGHT AS COOLER
TEMPERATURES HAVE MOVED PAST THE FA AND SOUTH WINDS WILL MAINTAIN
GOOD MIXING OVERNIGHT. EXPECT READINGS IN THE UPPER 50S/LOWER 60S.
MAX TEMPERATURES TUESDAY WILL RISE INTO THE LOWER 90S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 250 PM MDT MON AUG 13 2012
THE FIRST SIGNIFICANT WEATHER FEATURE TO IMPACT THE AREA DURING
THIS PERIOD WILL BE A STRONG UPPER SHORT WAVE TROUGH NOW OVER
BRITISH COLUMBIA AS SEEN IN WATER VAPOR IMAGERY. THIS TROUGH WILL
MOVE SOUTHEAST AND SWEEP ACROSS THE C-N PLAINS WED-WED NIGHT. AT
THE SURFACE A STRONG COLD FRONT WILL MOVE RAPIDLY SOUTH ACROSS THE
FORECAST AREA WEDNESDAY EVENING AND WILL CLEAR THE AREA LATE
WEDNESDAY NIGHT. THESE FEATURES WILL GIVE AN OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS MAINLY WEDNESDAY NIGHT. MUCH COLDER AIR
WILL SETTLE INTO THE REGION FOR THURSDAY AND FRIDAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S.
BOTH THE EC AND GFS SUGGEST A MODERATELY STRONG NORTHWEST FLOW
ALOFT FOR THE REMAINDER OF THE WEEK AND THROUGH THE WEEKEND. THE
EC IS MOSTLY DRY WITH THIS PATTERN BUT THE GFS SUGGESTS THE
POTENTIAL FOR SEVERAL EPISODES OF PRECIPITATION. BOTH MODELS HINT
AT SEVERAL WEAK...FAST-MOVING SHORT WAVE TROUGHS SLIDING SOUTHEAST
THROUGH THE FLOW BUT TIMING WILL BE DIFFICULT. LOW POPS ARE
INCLUDED IN THE EXTENDED FORECAST AS A RESULT. ANY CONVECTION
WHICH INITIATES ON THE CHEYENNE RIDGE WOULD MOVE INTO THE
AREA...AIDED BY SOUTHEAST SURFACE FLOW WHICH WILL ENHANCE STORM
INFLOW TO KEEP CONVECTION GOING FOR A FEW HOURS BEFORE
DISSIPATION.
TEMPERATURES OVER THE WEEKEND WILL RETURN TO CLOSER TO NORMAL
VALUES BUT THE EXTREME HEAT HAS ABATED FOR AT LEAST THE NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 541 PM MDT MON AUG 13 2012
COMPLICATED SET OF TAFS ESPECIALLY FOR KGLD. EVEN WITH THE
THUNDERSTORMS IN PROGRESS...MODELS STILL NOT IN COMPLETE AGREEMENT
AS TO WHERE TO PUT THE PRECIPITATION. BASED ON LATEST TRENDS FROM
OBSERVATIONAL DATA...THE HRRR IS DOING THE BEST RIGHT AND DOES
BRING IN A CLUSTER OF STORMS THROUGH THE EVENING. SO HAVE INSERTED
THUNDERSTORMS ACROSS AT KGLD DURING THIS TIME. BASED ON WHAT HAVE
SEEN UPSTREAM...IT WILL BE POSSIBLE THAT MVFR VISIBILITIES WILL
OCCUR AT KGLD. MODELS INDICATING LOW CLOUDS AFTER 06Z AT KGLD.
WILL LET THE THUNDERSTORM SITUATION EVOLVE BEFORE BECOMING MORE
PESSIMISTIC BUT DID INSERT A SCATTERED LOW DECK. FOR KMCK IT LOOKS
LIKE THUNDERSTORMS WILL NOT AFFECT THE TAF SITE AT THIS TIME.
HOWEVER...WILL TO MONITOR TO MAKE ADJUSTMENTS AS NEEDED. IF NO
THUNDERSTORMS OCCUR AT KMCK...CONDITIONS WILL BE VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...FS
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1130 PM CDT MON AUG 13 2012
.UPDATE...
ISSUED AT 1120 PM CDT MON AUG 13 2012
UPDATED FOR AVIATION SECTION ONLY.
UPDATE ISSUED AT 529 PM CDT MON AUG 13 2012
FROM A MESOSCALE PERSPECTIVE...THE CURRENT CONVECTION REMAINS IN A
QUASI-STEADY STATE. THE BEST THETA-E CONVERGENCE VIA LAPS DATA IS
BEING FOCUSED IN A ROUGHLY A 25 NAUTICAL MILE WIDE BAND ALONG THE
SURFACE FRONT...BUT WEST OF THE NORTH/SOUTH ORIENTED 2300 J2/K2
CAPE MAXIMUM ORIENTED NEAR INTERSTATE 55 IN SOUTHWEST ILLINOIS AND
SOUTHEAST MISSOURI. THE MAIN SURFACE LOW /WAVE/ IS OVER JACKSON
COUNTY ILLINOIS...AND WILL LIKELY MOVE NEAR MOUNT VERNON IN THE
NEXT COUPLE OF HOURS. UNFORTUNATELY...THE CORE OF THE HIGHER CAPE
VALUES HAS NOT BEEN PROGRESSING FURTHER NORTH...WHICH MAY LIMIT
UNCONDITIONAL SURFACE BASED INSTABILITY THROUGH THE EVENING.
THE HRRR AND 12KM NAM GUIDANCE APPEAR TO A HAVE A GENERAL IDEA OF
THE PROGRESSION OF THE FRONT AND OVERALL SYSTEM...BUT THE
PROJECTED FORECAST REFLECTIVITY GRIDS ARE ABOUT 80 TO 100 NM TOO
FAR TO THE SOUTHWEST. THE TIMING FOR SURFACE BASED CONVECTION WILL
BECOME MORE LIMITED THROUGH 00Z TUESDAY /7 PM CDT/ TONIGHT.
THERE IS A SUGGESTION IN THE 12KM NAM-WRF GUIDANCE THAT ENOUGH
FORECAST SHEAR /30-40KTS BULK SHEAR IN THE ZERO TO SIX KILOMETER
LAYER/ MOVING UP FROM EAST OF THE MISSISSIPPI RIVER IN WEST
TENNESSEE BETWEEN 23Z AND 02Z...THAT SOME MORE STORM DEVELOPMENT
AND ORGANIZATION MAY OCCUR TO SUSTAIN UPDRAFTS AS WEAK LOW LEVEL
WIND TRY TO INCREASE AT OR ABOVE THE DEVELOPING BOUNDARY LAYER
INVERSION AHEAD OF THE COLD FRONT. LOW LEVEL SHEAR IS QUITE
WEAK...SO ANY SUPPORT FOR RENEWED CONVECTION INTO WESTERN KENTUCKY
WILL HAVE TO COME FROM MID/UPPER LEVEL FORCING AND INSTABILITY.
THE KNQA VAD WIND PROFILE HAS BEEN SHOWING SOME INCREASE IN WINDS
NEAR 20KFT AS THE BASE OF THE UPPER WAVE. WHETHER THAT WILL BE
ENOUGH AS THE SHORTWAVE MOVES ACROSS WESTERN KY WILL BE THE 20
THOUSAND DOLLAR QUESTION.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 124 PM CDT MON AUG 13 2012
BOUNDARY AT 18Z WAS STILL OVER SOUTHEAST MISSOURI. AIR MASS
CONTINUES TO DESTABILIZE...WITH SOME ENHANCED CU SEEN NW OF
KCGI UP TOWARD PERRYVILLE MO. WILL CONTINUE TO MONITOR THIS
CORRIDOR AND POINTS EAST THROUGH THE AFTERNOON AND EARLY
EVENING FOR A FEW STRONG TO POSSIBLY SEVERE STORMS. OTHERWISE
THE ACTIVITY WILL PUSH EAST TONIGHT. QUIET WEATHER EXPECTED
TUESDAY AND TUESDAY NIGHT WITH VERY WEAK HIGH PRESSURE
FORECAST TO BUILD INTO THE AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 124 PM CDT MON AUG 13 2012
BY WEDNESDAY...UPPER HEIGHTS BEGIN TO RISE ACROSS THE AREA AND THIS
SHOULD RESULT IN WARMER TEMPERATURES...BUT WE SHOULD REMAIN RIGHT
AROUND NORMAL. THE SFC HIGH THAT WILL BE OVER THE AREA ON WEDNESDAY
WILL CONTINUE PROGRESSING TO THE EAST AND BY WEDNESDAY NIGHT...OUR
AREA SHOULD BE IN SOUTHERLY FLOW...WITH A WARM FRONT DEVELOPING TO
OUR SOUTH THAT WILL INCH SLOWLY TO THE NORTH. HOWEVER...WE WILL
REMAIN DRY WEDNESDAY NIGHT.
BY 12Z THURSDAY...A COLD FRONT WILL STRETCH FROM THE GREAT LAKES TO
WEST TEXAS...AND BE MOVING EASTWARD ACROSS OUR AREA WITH TIME. BOTH
THE GFS AND ECMWF HAVE BEEN IN REALLY GOOD AGREEMENT WITH THE
PROGRESSION OF THIS FRONT. HOWEVER...THE GFS/ECMWF HAVE DEFINITELY
SLOWED DOWN EVEN MORE WITH THE ONSET OF PRECIP...AND ACTUALLY
INDICATE THAT MOST OF THURSDAY MIGHT END UP BEING FAIRLY DRY...WITH
OUR WESTERN SECTIONS HAVING THE BEST CHANCES BY LATER IN THE
AFTERNOON. THIS WILL MEAN THAT WE WILL PROBABLY SEE WARMER HIGHS ON
THURSDAY AS WELL. WITH HIGHS IN THE UPPER 80S/LOWER 90S AND
DEW POINTS IN THE UPPER 60S/LOWER 70S...IT WILL DEFINITELY FEEL LIKE
SUMMER IS BACK. SO...WILL KEEP WITH MIDNIGHT SHIFTS THOUGHT OF
BREAKING THE THURSDAY TIME PERIOD INTO TWO...SHOWING BETTER CHANCES
DURING THE AFTERNOON. THE BULK OF THE RAIN WILL ARRIVE ON THURSDAY
NIGHT AS THE FRONT PASSES THROUGH...SO WILL CONTINUE WITH LIKELY
POPS.
BY 12Z FRIDAY...BOTH THE GFS/ECMWF/GEM HAVE THE FRONTAL BOUNDARY IN
OUR EASTERN COUNTIES OR JUST EAST OF THE AREA. BELIEVE WE WILL SEE
THE POSSIBILITY OF PRECIPITATION LINGERING FRIDAY MORNING MAINLY IN
THE SOUTHEASTERN HALF OF THE CWA. COULD ALMOST GO DRY FOR FRIDAY
AFTERNOON...BUT WITH THE MODELS TRENDING SLOWER WITH THIS
FRONT...WILL FORGO THAT FOR NOW.
FRIDAY NIGHT APPEARS DRY ATTM...AS HIGH PRESSURE BUILDS INTO THE
AREA FROM CANADA. MUCH COOLER TEMPERATURES SHOULD RESULT AS 850 MB
TEMPS DIVE INTO THE LOW TEENS BY SATURDAY. THIS SHOULD RESULT IN
TEMPERATURES THAT ARE WELL BELOW NORMAL. GIVEN THE VERY DRY AIR THAT
WILL LIKELY FILTER INTO THE REGION...HIGH TEMPERATURES WILL PROBABLY
END UP BEING HIGHER THAN WHAT THE CURRENT GUIDANCE NUMBERS ARE
SUGGESTING. THE GFS AND ECMWF INDICATE AN INCREASE IN
MOISTURE/PRECIPITATION AS EARLY AS SATURDAY NIGHT AND INTO
SUNDAY...AS SOME ENERGY WRAPS AROUND AN UPPER LOW IN EASTERN CANADA
AND DIVES DOWN INTO OUR AREA. THE ECMWF APPEARS TO BE FASTER AND A
LITTLE MORE GUNG HO ON THIS IDEA...SHOWING A MORE PRONOUNCED TROUGH
SWINGING THROUGH. WITH CURRENT MODEL DIFFERENCES...WILL LEAVE THINGS
DRY FOR THE WEEKEND AND MONDAY...UNTIL WE CAN OBTAIN SOME BETTER
CONSISTENCY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1120 PM CDT MON AUG 13 2012
MAIN ISSUES WITH THE 06Z TAF WILL COME IN THE 1ST COUPLE HOURS WITH
LEFT OVER ISOLD/SCT CONVECTION NEAR/SOUTH OF KOWB. BELIEVE THUNDER
IS OVER ELSEWHERE...THO COULD BE AN ISOLD SHOWER NEAR KEVV IN THE
06-08 TIME FRAME.
NEXT CONCERN WILL BE WITH POSSIBLE DENSE FOG FORMATION WHERE HEAVY
RAIN WAS RECEIVED TODAY. THIS IS MAINLY FROM NEAR KCGI THROUGH THE
KPAH SITE. HPAH RECEIVED OVER AN INCH OF RAIN THIS EVENING...AND
IS ALREADY MVFR AT 04Z. THIS SITE WILL LIKELY STAND THE HIGHEST
CHANCES OF TANKING DOWN TO IFR/LOW IFR IN THE 06-12Z TIME FRAME.
HOWEVER...LIGHT NW WINDS ARE JUST TO THE WEST...AND IF THESE
WINDS BREAK IN THROUGH THE INVERSION...THE FOG WOULD DISSIPATE.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...MEFFERT
AVIATION...MEFFERT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
559 AM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE, COMING EAST FROM INDIANA, WILL BRING SHOWERS AND
SCATTERED THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY UNTIL THE
LOW PASSES THROUGH TUESDAY EVENING. HIGH PRESSURE FROM IOWA WILL
FOLLOW WITH DRY SEASONABLE CONDITIONS WEDNESDAY AND THURSDAY. A
COLD FRONT, COMING SOUTHEAST FROM MONTANA, WILL PROVIDE THE NEXT
ROUND OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE ADJUSTED SHOWER CHANCES FOR THE EARLY THIS MORNING. BASED ON
RECENT RADAR AND SURFACE DATA PLUS HRRR MODEL OUTPUT, THE FIRST
BATCH OF ISOLATED SHOWERS HAS EXITED EAST OF THE MOUNTAINS. HAVE
ADDED ISOLATED FOG PATCHES THROUGH 9 AM.
BLEND OF RECENT WRF-NMM, HRRR, AND SREF MODEL OUTPUT THEN SHOW
CURRENT RADAR-DEPICTED SHOWERS AND ISOLATED THUNDERSTORMS OVER
WESTERN OHIO, WILL INCREASE IN COVERAGE LATER THIS MORNING AND
THROUGH THE AFTERNOON, AS THEY SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE CENTER, MOVING EAST FROM INDIANA.
HAVE LOW EXPECTATIONS REGARDING SEVERE POTENTIAL, AS NAM-MODEL
PROFILES AND MOST SREF MODEL MEMBERS SHOW INSTABILITY ACROSS THE
UPPER OHIO VALLEY WILL LIMITED BY THICKENING CLOUDS THIS MORNING.
THERE WILL BE MORE INSTABILITY AND HENCE MORE SEVERE POTENTIAL
EAST OF THE MOUNTAINS.
THIS SCENARIO IS FORTUNATE FOR THE UPPER OHIO VALLEY AS VERTICAL
WIND SHEAR, THAT IS, EFFECTIVE BULK SHEARS OF 30 PLUS KNOTS, WOULD
HAVE BEEN SUFFICIENT TO ORGANIZE RISING AIR COLUMNS INTO PRODUCING
SEVERE POTENTIAL.
AS LOW PRESSURE SYSTEM EXITS EAST TONIGHT, SHOWERS WILL END WEST
TO EAST LATE. DUE TO NOCTURNAL-COOLING OF A RAIN-MOISTENED SURFACE
LAYER, PATCHY FOG CAN DEVELOP.
FORECASTED TEMPERATURES TO BE SLIGHTLY COOLER THAN NORMAL TODAY,
THEN NEAR NORMAL TONIGHT, AS INDICATED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
BLEND OF SREF AND GFS MODEL OUTPUT SHOW HIGH PRESSURE COMING EAST
FROM IOWA WILL PROVIDE DRYING AND SUBSIDENCE ACROSS THE UPPER OHIO
VALLEY WEDNESDAY AND THURSDAY. DO REALIZE THERE WILL BE A TRAILING
TROUGH ALOFT WEDNESDAY THAT COULD SET OFF ISOLATED SHOWERS, BUT
CONCUR WITH GFS AND NAM MOS THAT PROBABILITIES WILL BE TOO LOW TO
MENTION.
A STRONGER LOW PRESSURE SYSTEM WILL MOVE EASTWARD ACROSS SOUTHERN
CANADA DURING THIS PERIOD, WHICH WILL PUSH A COLD FRONT THROUGH
THE UPPER OHIO VALLEY FRIDAY. SO HAVE ADDED A CHANCE OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY NIGHT AND FRIDAY.
FORECASTED TEMPERATURES TO BE NEAR SEASONABLE LEVELS BASED ON
RECENT GFS AND NAM MOS AND SREF MEAN VALUES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
POST-COLD FRONTAL 850 TEMPS OF 6-7C, WITH A COLD TROUGH ALOFT
PASSING THROUGH THE UPPER OHIO VALLEY, MAY CONTINUE CLOUDS AND
SCATTERED SHOWERS THROUGH DAYTIME SATURDAY. FORECASTED
TEMPERATURES TO BE ABOUT 5 DEGREES COOLER THAN NORMAL.
ENSUING HIGH PRESSURE WILL PROVIDE DRY BUT COOLER THAN NORMAL
TEMPERATURES SUNDAY AND MONDAY, JUDGING FROM RECENT GFS AND ECMWF
MOS.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
ISOLATED FOG PATCHES CAN PROVIDE MVFR VISIBILITIES THROUGH 13Z.
THEN VFR CONDITIONS WILL PERSIST UNTIL RAIN SHOWERS AND
SCATTERED THUNDERSTORMS SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE SYSTEM, THAT WILL CROSS THE REGION LATE THIS AFTERNOON,
AND EXIT EAST EARLY TONIGHT. MVFR CIGS AND VIS CAN BE EXPECTED
ESPECIALLY IN ANY THUNDERSTORMS BUT WITH LIMITED CONFIDENCE IN
TSRA COVERAGE AT THIS POINT WILL LEAVE IT OUT OF TAFS.
PATCHES OF FOG, WITH MAINLY MVFR RESTRICTIONS, CAN DEVELOP TONIGHT DUE TO
NOCTURNAL COOLING OF A RAIN-MOISTENED SURFACE LAYER.
.OUTLOOK...WEDNESDAY THROUGH SATURDAY...
EXPECT VFR WEDNESDAY AND THURSDAY DUE TO PASSING HIGH PRESSURE.
THE NEXT POSSIBILITY OF RESTRICTIONS WILL BE FRIDAY INTO SATURDAY
DUE TO SHOWERS AND STORMS ASSOCIATED WITH A COLD FRONTAL PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
457 AM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE, COMING EAST FROM INDIANA, WILL BRING SHOWERS ACROSS THE
UPPER OHIO VALLEY UNTIL THE LOW PASSES THROUGH TUESDAY EVENING.
HIGH PRESSURE FROM IOWA WILL FOLLOW WITH DRY SEASONABLE CONDITIONS
WEDNESDAY AND THURSDAY. A COLD FRONT, COMING SOUTHEAST FROM
MONTANA, WILL PROVIDE THE NEXT ROUND OF SHOWERS AND THUNDERSTORMS
FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE AGAIN ADJUSTED SHOWER CHANCES FOR THE EARLY MORNING TO NO MORE
THAN ISOLATED COVERAGE, BASED ON RECENT RADAR AND SURFACE DATA
PLUS HRRR MODEL OUTPUT.
BLEND OF RECENT WRF-NMM, HRRR, AND SREF MODEL OUTPUT THEN SHOW
CURRENT RADAR-DEPICTED SHOWERS AND ISOLATED THUNDERSTORMS OVER
WESTERN OHIO, WILL INCREASE IN COVERAGE LATER THIS MORNING AND
THROUGH THE AFTERNOON, AS THEY SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE CENTER, MOVING EAST FROM INDIANA.
HAVE LOW EXPECTATIONS REGARDING SEVERE POTENTIAL, AS NAM-MODEL
PROFILES AND MOST SREF MODEL MEMBERS SHOW INSTABILITY ACROSS THE
UPPER OHIO VALLEY WILL LIMITED BY THICKENING CLOUDS THIS MORNING.
THERE WILL BE MORE INSTABILITY AND HENCE MORE SEVERE POTENTIAL
EAST OF THE MOUNTAINS.
THIS IS FORTUNATE FOR THE UPPER OHIO VALLEY AS VERTICAL WIND
SHEAR, EFFECTIVE BULK SHEARS OF 30 PLUS KNOTS, WOULD HAVE BEEN
SUFFICIENT TO ORGANIZE RISING AIR COLUMNS INTO PRODUCING SEVERE
POTENTIAL.
AS LOW PRESSURE SYSTEM EXITS EAST TONIGHT, SHOWERS WILL END WEST
TO EAST LATE. DUE TO NOCTURNAL-COOLING OF A RAIN-MOISTENED SURFACE
LAYER, PATCHY FOG CAN DEVELOP.
FORECASTED TEMPERATURES TO BE SLIGHTLY COOLER THAN NORMAL TODAY,
THEN NEAR NORMAL TONIGHT, AS INDICATED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
BLEND OF SREF AND GFS MODEL OUTPUT SHOW HIGH PRESSURE COMING EAST
FROM IOWA WILL PROVIDE DRYING AND SUBSIDENCE ACROSS THE UPPER OHIO
VALLEY WEDNESDAY AND THURSDAY. DO REALIZE THERE WILL BE A TRAILING
TROUGH ALOFT WEDNESDAY THAT COULD SET OFF ISOLATED SHOWERS, BUT
CONCUR WITH GFS AND NAM MOS THAT PROBABILITIES WILL BE TOO LOW TO
MENTION.
A STRONGER LOW PRESSURE SYSTEM WILL MOVE EASTWARD ACROSS SOUTHERN
CANADA DURING THIS PERIOD, WHICH WILL PUSH A COLD FRONT THROUGH
THE UPPER OHIO VALLEY FRIDAY. SO HAVE ADDED A CHANCE OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY NIGHT AND FRIDAY.
FORECASTED TEMPERATURES TO BE NEAR SEASONABLE LEVELS BASED ON
RECENT GFS AND NAM MOS AND SREF MEAN VALUES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
POST-COLD FRONTAL 850 TEMPS OF 6-7C, WITH A COLD TROUGH ALOFT
PASSING THROUGH THE UPPER OHIO VALLEY, MAY CONTINUE CLOUDS AND
SCATTERED SHOWERS THROUGH DAYTIME SATURDAY. FORECASTED
TEMPERATURES TO BE ABOUT 5 DEGREES COOLER THAN NORMAL.
ENSUING HIGH PRESSURE WILL PROVIDE DRY BUT COOLER THAN NORMAL
TEMPERATURES SUNDAY AND MONDAY, JUDGING FROM RECENT GFS AND ECMWF
MOS.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL CONTINUE UNTIL HEAVIER RAIN SHOWERS AND
THUNDERSTORMS SPREAD EASTWARD AHEAD OF THE LOW PRESSURE SYSTEM
THAT WILL CROSS THE REGION LATE THIS AFTERNOON. MVFR CIGS AND VIS
CAN BE EXPECTED ESPECIALLY IN ANY THUNDERSTORMS BUT WITH LIMITED
CONFIDENCE IN TSRA COVERAGE AT THIS POINT WILL LEAVE IT OUT OF
TAFS.
.OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
MVFR/IFR CONDITIONS IN STRATUS/FOG COULD BE POSSIBLE BEHIND THE
FRONT TUESDAY NIGHT. VFR CONDITIONS SHOULD THEN RETURN FOR
WEDNESDAY AND THURSDAY DUE TO PASSING HIGH PRESSURE. THE NEXT
POSSIBILITY OF RESTRICTIONS WILL BE FRIDAY INTO SATURDAY DUE TO
SHOWERS AND STORMS ASSOCIATED WITH A COLD FRONTAL PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
202 AM EDT TUE AUG 14 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 407 PM EDT MON AUG 13 2012
WV LOOP AND RAOBS INDICATE UPPER TROUGHS FROM NORTHERN ONTARIO
THROUGH THE WESTERN GREAT LAKES REGION. STRONGEST SHORTWAVES IN
THE MEAN TROUGH ARE OVER NORTHERN ONTARIO AND ALSO SOUTHERN LOWER
MICHIGAN. SHORTWAVE BTWN THE TWO TROUGHS AND SFC TROUGH MERGED UP
WITH LAKE BREEZES OVR CNTRL UPR MICHIGAN EARLIER THIS AFTN TO KICK
OFF ISOLD SHRA AND STORMS. CONVECTIVE DEPTH WAS SHALLOW...BUT RADAR
ESTIMATED PRECIP AMOUNTS UP TO 1-1.5 INCHES SEEMED REASONABLE AS
STORM MOTION WAS SLOW AND EVEN TRIED TO BACKBUILD OVR EXTREME
SOUTH CENTRAL MARQUETTE COUNTY AS ONE STORM BRIEFLY BECAME A RIGHT
MOVER.
AS OF 19Z...THE MESS OF THE SYNOPTIC TROUGH AND LAKE BREEZE
CONVERGENCE BOUNDARY IS ORIENTED FM ROUGHLY WATERSMEET THROUGH JUST
NORTH OF CRYSTAL FALLS AND IRON MOUNTAIN AND EAST TOWARD NEWBERRY
AND SAULT STE MARIE. ISOLD-SCATTERED SHRA/TSRA ARE LOCATED ALONG THE
TROUGH WITH STORM MOTIONS GENERALLY ESE AROUND 15 MPH. BASED ON
RADAR TRENDS AND HRRR MODEL...HIGHLIGHTED HIGHEST POPS EARLY THIS
EVENING OVR SCNTRL UPR MICHIGAN...WITH DIMINISHING TREND BY LATE
EVENING DUE TO LOSS OF DAYTIME INSTABILITY AND LOW-LEVEL
CONVERGENCE. STILL...AT LEAST ISOLD SHRA/TSRA MAY TRY TO STICK
AROUND THROUGH EVEN AFTER MIDNIGHT IN THE FAR SCNTRL WITH LINGERING
WEAKER SHORTWAVE ENERGY OVERHEAD AND STEEPER MID-LEVEL LAPSE RATES
AND H85-H7 MOISTURE. ALL CONVECTION SHOULD BE OUT OF CWA BY LATE
TONIGHT. TEMPS OVER INTERIOR WEST MAY TRY TO FALL OFF INTO THE 40S
LATE TONIGHT WITH A LOWER PWAT MIN LOCATED THERE. A BIT OF WIND AND
POSSIBLE SCT-BKN MID CLOUDS SHOULD KEEP REST OF CWA IN THE 50S.
ON TUESDAY...DAY STARTS OFF WITH THE SCT-BKN MID CLOUDS WITH CU
BUILDUP BY LATE MORNING AS CONVECTIVE TEMPS ARE IN THE LOWER 70S.
SHORTWAVE ON BACK SIDE OF LARGER SCALE TROUGH IN CNTRL SASKATCHEWAN
AND/OR MANITOBA FCST TO SLIDE INTO CNTRL CWA BY MID AFTN. GIVEN
SIMILAR FCST SBCAPES IN THE 700-1000J/KG RANGE COULD SEE REPEAT
PERFORMANCE OF TODAY...OR AT LEAST SOMEWHAT SIMILAR...WITH
ISOLD-SCATTERED SHRA/TSRA FORMING SHORTLY AFTER CONVECTIVE TEMPS
ARE REACHED. MAIN DIFFERENCE IS THE SHORTWAVE IS NOT AS STRONG AND
LOW-LEVEL CONVERGENCE WILL BE STRICTLY DRIVEN BY LAKE BREEZES FM
LAKE SUPERIOR/LAKE MICHIGAN. MSLP/WIND PATTERN POINTS TO AREA BTWN
SAW-IMT-ESC STAND TO SEE BEST COVERAGE OF SHRA/TSRA. FREEZING LEVELS
AROUND 11KFT AGL AND H85-H7 WINDS FAIRLY SIMILAR TO TODAY AS
WELL...SO AGAIN COULD SEE SLOW MOVING STORMS WITH MAIN HAZARDS
LIGHTNING AND HEAVY DOWNPOURS. SMALL HAIL COULD ALSO OCCUR WITH
STRONGEST STORMS. CONVERGENCE WANES BY LATE AFTN SO KEPT WITH IDEA
THAT POPS WILL BE OUT OF THE CWA BY EARLY TUESDAY EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 407 PM EDT MON AUG 13 2012
TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON...THE UPPER LEVEL TROUGH
WITH AXIS EXTENDING SOUTHWARD FROM CENTRAL ONTARIO THROUGH THE
EASTERN HALF OF UPPER MI AND INTO THE WESTERN HALF OF LOWER MI WILL
SHIFT EASTWARD OVERNIGHT...REACHING THE LOWER GREAT LAKES BY
WEDNESDAY AFTERNOON. AS THIS TROUGH SHIFTS EASTWARD A SURFACE AND
WEAK UPPER LEVEL RIDGE WILL BUILD INTO THE UPPER GREAT LAKES
REGION...BRIEFLY BRINGING AND END TO THE CHANCES OF PRECIPITATION.
WEDNESDAY EVENING THROUGH FRIDAY NIGHT...AS THE SURFACE RIDGE AND
UPPER LEVEL RIDGE BEGIN TO SHIFT EASTWARD TO THE LOWER GREAT LAKES
ATTENTION WILL THEN TURN TO AN APPROACHING LOW PRESSURE SYSTEM
CENTERED OVER NORTHERN MN...WITH ASSOCIATED UPPER LEVEL TROUGH TO
THE WEST OF THE SURFACE LOW...INDICATED BY BOTH THE
EC/GFS...SUGGESTING THAT THE SURFACE LOW IS EXPECTED TO INTENSIFY.
THE LOW WILL PASS TO THE NORTH OF THE UPPER PENINSULA BY 12Z
THURSDAY AS IT DRAGS A COLD FRONT THROUGH INTO CENTRAL UPPER MI
AROUND THE SAME TIME AS INDICATED BY PLOTTING MSLP/850 THETA
E/SURFACE WINDS. THE MAIN AREA OF PRECIPITATION WILL LIKELY BE
PEGGED TO THE FRONT OF THE COLD FRONT AS THE FORCING APPEARS THE
GREATEST ALONG THIS AREA AS SHOWN BY PLOTTING 500-300MB DIVQ ALONG
WITH 1000-500 RH VALUES. MU CAPE VALUES AREA PROGGED TO BE AROUND
500-800 J/KG OVER MUCH OF THE AREA OVER THE WESTERN HALF OF THE AREA
AROUND 06Z SHIFTING TO THE EAST HALF AROUND 12Z THURSDAY. 0-6 KM
SHEAR VALUES ARE EXPECTED TO BE AROUND 30 TO 35 KNOTS AHEAD OF THE
FRONT WITH VALUES INCREASING TO AROUND 50 KNOTS ALONG AND BEHIND THE
FRONT. SHEAR VALUES BEING MARGINAL FOR SEVERE WEATHER AHEAD OF THE
FRONT ALONG WITH CAPE IN THE HAIL GROWTH ZONE AROUND 100-200 J/KG
WOULD INDICATE ONLY A MARGINAL THREAT OF HAIL. DCAPE VALUES ARE
FAIRLY LOW WITH VALUES AROUND 100-150 J/KG DUE TO A LACK OF DRY AIR
IN THE MID LEVEL. THURSDAY NIGHT THROUGH FRIDAY NIGHT THE UPPER
LEVEL TROUGH WILL REMAIN OVER UPPER MI...WHILE SHIFTING EVER SO
SLOWLY TO THE EAST AS THE SURFACE LOW PULLS OT THE NORTHEAST TO
WESTERN QUEBEC. THE COOLER AIR WRAPPING AROUND THE BACK SIDE OF THE
LOW ALONG WITH DECREASED TEMPERATURES ALOFT...AROUND 4 TO 6C AT
H850...WILL HELP TO INCREASE THE CHANCE OF LAKE EFFECT SHOWERS OVER
THOSE AREAS FAVORED BY NORTH WINDS. HAVE ALSO INCREASED THE WINDS
OVER THE CENTRAL AND EASTERN PORTIONS OF THE LAKE AS CAA KICKS
IN...EXPECT THE STRONGER WINDS TO MIX DOWN AS H850 WINDS ARE AROUND
35 KNOTS. WILL HAVE TO KEEP AN EYE ON THIS THROUGH LATER SHIFTS.
SATURDAY THROUGH MONDAY...BOTH THE EC AND GFS KEEP THE UPPER LEVEL
500MB TROUGH SITUATED OVER MUCH OF THE UPPER GREAT LAKES
REGION...HELPING TO KEEP ON AND OFF CHANCES OF SHOWERS IN THE
FORECAST THROUGH MONDAY AFTERNOON. THE BEST CHANCE OF RAIN SHOWERS
THROUGH THIS PERIOD WOULD BE MONDAY AS A SURFACE LOW APPROACHES THE
AREA FROM THE WEST. MOISTURE THROUGH THIS TIME PERIOD APPEARS TO BE
FAIRLY LIMITED AS A SURFACE HIGH WILL REMAIN JUST TO THE SOUTH OF
THE REGION KEEPING DRY WESTERLY WINDS PUSHING INTO THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 142 AM EDT TUE AUG 14 2012
MAIN ISSUE OVERNIGHT IS FOG. SHALLOW TRANSIENT RADIATIONAL FOG HAS
BEEN A COMMON OCCURRENCE AT KIWD THE LAST FEW NIGHTS...AND IT
APPEARS THAT WILL BE THE CASE AGAIN. EXPECT WIDE VIS FLUCTUATIONS
OVER SHORT PERIODS OF TIME THERE (IFR TO VFR). SINCE RAINFALL
OCCURRED AT KSAW...EXPECT RADIATIONAL FOG (PROBABLE IFR VIS) TO
DEVELOP OVERNIGHT. KCMX SHOULD REMAIN VFR. VFR CONDITIONS WILL
PREVAIL AT KIWD/KCMX TODAY. AT KSAW...LAKE BREEZES AND DAYTIME
HEATING WILL PROBABLY RESULT IN ISOLD/SCT CONVECTION IN CNTRL UPPER
MI. WITH UNCERTAINTY IN COVERAGE/LOCATION OF PCPN...ONLY INCLUDED
VCSH IN THE AFTN. MIGHT SEE SOME TSRA...BUT INSTABILITY WILL BE LESS
THAN YESTERDAY WHEN TSRA WERE MORE NUMEROUS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT MON AUG 13 2012
QUIET MARINE WEATHER THROUGH WEDNESDAY AS HIGH PRESSURE SLIDES
OVERHEAD. BY LATER THURSDAY...PASSAGE OF A STRONG COLD FRONT WILL
KICK UP NORTHWEST WINDS TO 25 KTS OVER MUCH OF THE LAKE. WINDS TO 30
KTS ARE EXPECTED OVER CENTRAL AND EASTERN SECTIONS AS COLDER AIRMASS
PUSHES ACROSS THE STILL WARMER WATERS OF LAKE SUPERIOR. THE UNSTABLE
PROFILE WILL LEAD TO BUILDING WAVES THURSDAY NIGHT INTO FRIDAY.
EXPECT THE STRONG WINDS AND HIGH WAVES TO CONTINUE INTO SATURDAY
BEFORE DIMINISHING WITH ARRIVAL OF HIGH PRESSURE. EXPECT THE HIGHER
WAVES TO LEAD TO AN INCREASED RISK OF RIP CURRENTS LATE THURSDAY
THROUGH FRIDAY ALONG THE BEACHES OF EASTERN LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KEC
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1212 AM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 311 PM EDT MON AUG 13 2012
RAIN SHOWERS WILL CONTINUE INTO TONIGHT AS LOW PRESSURE MOVES
SOUTH OF LOWER MICHIGAN. FAIR WEATHER WILL FOLLOW FOR TUESDAY AND
WEDNESDAY BUT STRONG THUNDERSTORMS ARE POSSIBLE THURSDAY NIGHT AS
A COLD FRONT MOVES THROUGH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 311 PM EDT MON AUG 13 2012
LOWERED POPS A BIT TONIGHT AND TUESDAY MORNING. DROPPED POPS FOR
TUESDAY AFTERNOON AND WEDNESDAY NIGHT.
RADAR TRENDS AND HRRR INDICATE THAT MOST OF THE SHOWERS WILL BE
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA WITH MORE SCATTERED
RAIN SHOWERS ACROSS THE NORTH. ADJUSTED POPS TO REFLECT THIS AND
ADDED AREAS OF FOG AFTER MIDNIGHT GIVEN THE EXPECTED LIGHT WINDS
AND HIGH LOW LEVEL RH. LEFT THUNDER OUT OF THE FORECAST DUE TO
MARGINAL INSTABILITY BUT CANNOT RULE OUT AN ISOLATED THUNDERSTORM.
NAM AND GFS CROSS SECTIONS SHOW A QUICKER DEPARTURE OF THE DEEPER
RH ON TUESDAY...SO TRIMMED POPS FOR THE MORNING AND DROPPED THEM
FOR THE AFTERNOON FOR ALL ZONES.
WEAK SFC RIDGING MOVES IN FOR TUESDAY NIGHT AND WEDNESDAY BUT
UPPER TROUGH AMPLIFICATION WILL LEAD TO STRONG SFC COLD FRONT
MOVING TOWARDS LOWER MICHIGAN WEDNESDAY NIGHT. AT HIS POINT IT
APPEARS THE ST ROMS ALONG THE FRONT WILL HOLD OFF UNTIL LATER
THURSDAY...SO DROPPED POPS FOR WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 311 PM EDT MON AUG 13 2012
MAIN FOCUS OF THE FCST CONTINUES TO BE THE STRONG FRONT EXPECTED TO
MOVE THROUGH THU/THU NIGHT. THE WEEKEND LOOKS COOL AND POTENTIALLY A
LITTLE UNSETTLED WITH TROUGHING HANGING OUT OVER THE REGION. NO REAL
CHANGES WERE MADE TO THE FCST.
PCPN CHANCES WILL BE GRADUALLY INCREASING AT THE BEGINNING OF THE
LONG TERM PERIOD ON THU. THIS OCCURS AS UPPER RIDGING MOVES EAST OF
THE AREA...AND THE STRONG UPPER SYSTEM CURRENTLY MOVING INTO NW
BRITISH COLUMBIA DIGS INTO THE REGION. MODELS CONTINUE TO INDICATE
THAT MOST OF THE PCPN WITH THE SFC FRONT WILL BE RIGHT ALONG AND
JUST BEHIND THE FRONT. THIS IS WHERE THE TAIL END OF THE UPPER
TROUGH AND SFC FRONT OVERLAP.
IT CONTINUES TO LOOK LIKE CLOUDS OUT AHEAD OF THE FRONT WILL
SUPPRESS DIURNAL INSTABILITY SOME. MODELS INDICATE THAT AT LEAST A
FEW HUNDRED J/KG OF ML CAPE WILL BE LIKELY...AND THE GFS /LIKELY
OVERDONE DUE TO SFC DEW POINTS/ SHOWS MORE POTENTIAL INSTABILITY.
DEEP LAYER SHEAR STILL LOOKS TO BE MARGINAL ALONG THE FRONT...WITH
MUCH BETTER VALUES POST-FRONTAL. WE STILL EXPECT THAT STRONG STORMS
WILL BE POSSIBLE DUE TO THE STRENGTH OF THE FRONT AND UPPER TROUGH
THAT COULD COMPENSATE FOR MARGINAL SHEAR AND INSTABILITY.
ONCE THE UPPER TROUGH SUPPORTING THE FRONT MOVES IN...IT LOOKS TO
BECOME ESTABLISHED OVER THE AREA THROUGH THE REMAINDER OF THE
PERIOD. WE WILL SEE SHORT WAVE ENERGY CONTINUE TO DIVE INTO THE MEAN
TROUGH OVER THE GREAT LAKES...HELPING TO REINFORCE IT. THIS WILL
KEEP A CHC OF MAINLY DIURNAL SHOWERS AROUND THROUGH NEXT MON. THE
AREA WILL SEE FALL-LIKE TEMPS IN THE 60S AND TO AROUND 70 FOR THE
WEEKEND. TEMPS WILL SLOWLY MODIFY INTO THE 70S BY MON NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1212 AM EDT TUE AUG 14 2012
CONFIDENCE IS FAIRLY HIGH THAT WIDESPREAD IFR/LIFR CONDITIONS WILL
SETTLE IN TONIGHT AFTER 06Z-08Z. THE LOW CIGS/VSBYS SHOULD LIFT
BY MID MORNING TUESDAY WITH VFR FOLLOWING FOR THE AFTERNOON. A FEW
ISOLD TSTMS COULD DEVELOP TUESDAY AFTERNOON... BUT STILL DID NOT
PUT MENTION OF TS/CB IN THE TAFS SINCE CONFIDENCE IS TOO LOW.
&&
.MARINE...
ISSUED AT 311 PM EDT MON AUG 13 2012
SOME FOG IS POSSIBLE ALONG THE COAST WHERE COOLER WATERS HAVE BEEN
STIRRED UP BY LAST WEEKS STORM. OTHERWISE...NO SIGNIFICANT WEATHER
IS EXPECTED UNTIL THURSDAY OR THURSDAY NIGHT WHEN A COLD FRONT
BRINGS THE CHANCE FOR STRONG THUNDERSTORMS.
&&
.HYDROLOGY...
ISSUED AT 311 PM EDT MON AUG 13 2012
RAINS TODAY AND TONIGHT SHOULD NOT AFFECT RIVER LEVELS. SOME
HEAVIER RAINS ARE POSSIBLE THURSDAY AND THURSDAY NIGHT WITH A HALF
TO AN INCH OF BASIN AVERAGE QPF POSSIBLE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...MEADE
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
325 AM CDT TUE AUG 14 2012
.DISCUSSION...
SEVERAL WEAK SHRTWV/S ACROSS THE DAKOTAS ARE CAUSING SOME CONCERNS
WITH ISOLD/SCT SHRA/TSRA IN SW/WC MN DURING THE AFTN/EVENING AS
AMPLE MID-LEVEL MOISTURE BEGINS TO ADVECT INTO THE AREA.
WV IMAGERY HAS THE MAIN SHRTWV ACROSS SW SD EARLIER THIS MORNING
WHICH IS ASSOCIATED WITH A DECAYING MCS FROM MT. BUT...THE FACT
THAT SOME SHRA CONTINUED AHEAD OF ANOTHER SHRTWV EMBEDDED IN
WESTERN ND DOES ALLOW FOR AT LEAST SOME ISOLD POPS IN WC/SW MN
DURING THE AFTN/EVENING OR BEFORE A MORE ESTABLISHED LLJ DEVELOPS
LATER TONIGHT IN THE DAKOTAS/WESTERN MN.
LATEST ECMWF HAS DEVELOPED A MORE SIGNIFICANT THERMAL BOUNDARY
ACROSS NE/SD LATER TODAY...WHICH WILL LEAD TO BETTER DYNAMICS
ACROSS SW MN AFT DARK AS THE LLJ DEVELOPS. EVEN THE LATEST
VWP/PROFILER NETWORK AT 85H IN NE INDICATED A BETTER LLJ THIS
MORNING COMPARED TO THE MODELS 6 HR FORECAST ACROSS SW SD.
THEREFORE...AM LEANING TOWARD HIGHER POPS IN SW/WC MN THIS
AFTN/EVENING...THEN SPREADING THIS ACTIVITY ACROSS S MN DURING THE
OVERNIGHT HRS...BEFORE THE NOCTURNAL LLJ DECREASES WED MORNING.
THIS SCENARIO ALSO PLAYS HAVOC ON TEMPS FOR WED WHICH MAY BE
COOLER IF MORE CLOUD COVER IS EXPECTED...ESPECIALLY IN THE NE FA.
OVERALL...THE BEST CHC OF WIDESPREAD CONVECTION IS WED
EVENING...WITH THE ACTIVITY QUICKLY MOVING NE/E DURING THE
OVERNIGHT HRS. SOME LINGERING SHRA ARE POSSIBLE IN THE FAR E FA
BEFORE NOON THU...BUT MOST OF THE ACTIVITY SHOULD BE DONE BY 12Z.
AS PER SVR WX...AMPLE 0-6KM WIND SHEAR AND CAPES ARND 2000 J/KG
WED EVENING SHOULD BE ENOUGH TO GENERATE ORGANIZED CONVECTIVE
STORMS. THE BEST 0-1KM SHEAR IS WELL AHEAD OF THE MAIN FRONTAL
BOUNDARY. HOWEVER...IF AN ESTABLISHED COMPLEX OF TSRA
DEVELOPS...THERE IS ENOUGH SHEAR TO POSSIBLY GENERATE A COLD POOL
LEADING TO A BOW ECHO SCENARIO. WILL HIGHLIGHT THE MORNING
HWO FOR THE SVR WX POTENTIAL...ALSO SEE THE LATEST SPC DAY2 OUTLOOK.
AFTER THU...CHC/S OF PRECIPITATION REMAIN LOW WITH A PREDOMINATE
W/NW FLOW ALOFT. TEMPS WILL REMAIN BLW NORMAL FOR THE MOST PART
THRU SUNDAY...WITH SOME MODIFICATIONS EARLY NEXT WEEK AS A MORE
WESTERNLY FLOW DEVELOPS...AND WARMER AIR FROM THE PLAINS BEGINS TO
SPILL ACROSS THE MIDWEST.
EVEN THOUGH SEVERAL SHRTWV/S DIVE S/SE FROM THIS NW FLOW
DEVELOPING THIS WEEKEND...MOISTURE WILL LIKELY BE LIMITED DUE TO
THE STRENGTH OF THE DRIER AIR MASS AND HOW FAR SOUTH THE FRONTAL
BOUNDARY MOVES TO THE SE U.S. OVER THE WEEKEND ..JLT..
&&
.AVIATION.../06Z TAF ISSUANCE/
PREVALENT SURFACE HIGH PRESSURE WILL YIELD LIGHT WINDS AND VFR
CONDITIONS THROUGH THE PERIOD...WITH THE EXCEPTION OF THE
POSSIBILITY OF A PERIOD OF FOG BETWEEN 09Z AND 13Z. CONCERN MAINLY
LIES OVER WEST CENTRAL WI AND SOUTH CENTRAL MN /KEAU-KRNH-
KRWF/...WHERE MEASURABLE PRECIP FELL MONDAY AND THE RAP INDICATES
DEWPOINT DEPRESSIONS DECREASE TO AROUND 2 OVERNIGHT. DO NOT THINK
IT WILL BE A CRYSTAL CLEAR SKY OVERNIGHT...WITH SHORT TERM MODELS
INDICATING LINGERING MOISTURE CIRCA 850MB...WHICH WAS CONFIRMED BY THE
00Z MPX RAOB. THEREFORE EXPECT SCATTERED CLOUDS AROUND 6K FEET
MIGHT ABATE SOME OF THE FOG RISK...PARTICULARLY AT KRWF. HAVE
THEREFORE MAINTAINED ONLY MINOR MVFR VSBY REDUCTIONS AT KRWF AND
KRNH. LIFR VSBYS OR EVEN BRIEF VLIFR VSBYS APPEAR LIKELY AT KEAU WHERE
A HALF INCH OF RAIN FELL MONDAY AFTERNOON. THE REMAINDER OF THE
TAF PERIOD WILL FEATURE FEW-SCT CUMULUS NEAR KRNH AND KEAU...AND
INCREASING MID/HIGH CLOUDS FROM WEST TO EAST AS THE NEXT SYSTEM
APPROACHES.
KMSP...VFR THROUGH THE PERIOD WITH LIGHT AND VARIABLE WINDS UNDER
THE INFLUENCE OF HIGH PRESSURE. DIRECTIONAL COMPONENT WILL BE
NORTHWESTERLY ON TUESDAY. WINDS WILL BACK TO SOUTH/SOUTHEAST IN DIRECTION
AND MID CLOUDS WILL BEGIN TO INCREASE AFTER 00Z WED AS A SURFACE
TROUGH APPROACHES.
/OUTLOOK/
.WEDNESDAY...VFR WITH MVFR AND TSRA POSSIBLE EARLY MORNING AND
AGAIN AT NIGHT. NIGHT COLD FROPA BTWN 00Z AND 06Z. WINDS S AT
10G15KTS SHIFTING TO NW 10G15KTS WITH THE FROPA.
.THURSDAY...VFR. WINDS BECOMING NW AT 15G25KTS.
.FRI...VFR. WINDS NW AOB 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/LS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
351 AM CDT TUE AUG 14 2012
.DISCUSSION...
FORECAST CONCERNS EARLY ON WILL BE ANY LINGERING PRECIPITATION AND
CLOUDS TODAY...THEN PRECIPITATION CHANCES TONIGHT AND BETTER
CHANCES FOR RAIN WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
THE 00Z H5 PATTERN HAD THE CENTRAL PLAINS UNDER NORTHWEST FLOW ALOFT
WITH A COUPLE OF EMBEDDED SHORTWAVES. AT 04Z...THE SHORTWAVE OVER
MONTANA HAD ALREADY PUSHED INTO THE DAKOTAS...AND THE SHORTWAVE OVER
COLORADO WAS ADVANCING INTO WRN KANSAS. THE 00Z 80KT H3 JET WAS OVER
NEBRASKA AND THERE WAS SOME DECENT UPR LEVEL DIVERGENCE OVER
COLORADO. THE H85 THETA-E AXIS AXIS AT 06Z WAS OVER THE WESTERN
PLAINS WITH H85 WINDS PER THE VWPS FM THE SOUTH AT AROUND 30 TO
35KTS. STEEP MID LEVEL LAPSE RATES OF 7 TO 8.5 DEG C/KM WERE ALSO IN
THIS REGION. BY 08Z...THE LAST WSR-88D RADAR MOSAIC HAD SOME
SHOWERS AND THUNDERSTORMS FROM THE CNTRL DAKOTAS BACK TOWARD WRN
NEBRASKA...A FEW ECHOES IN CENTRAL AND EASTERN NEBRASKA THAT HAD
WEAKENED FROM EARLIER THIS AM...AND A MORE ORGANIZED AREA OF
PRECIPITATION OVER KANSAS. AN EARLIER RUN OF THE HRRR DID NOT
PICK UP ON THE TSRA FOR CENTRAL NEBRASKA AND THE LATEST RUN IS
DOING A BETTER JOB...WITH A CONTINUED WEAKENING TREND AS THE
STORMS MOVE EAST.
THIS MORNING...THE LOW LEVEL JET IS PROGGED TO CONTINUE FROM 30 TO
35KTS FROM THE WCNTRL DAKOTAS INTO CNTRL NEBRASKA...SOUTH INTO
WRN AND CNTRL KANSAS WITH SOME VEERING DURING THE MORNING. THE
TRENDS ON THE IR SATELLITE WEAKENING AND THE NORTHERN WAVE REMAINS
WEAK AS IT MOVES THRU THE PLAINS WITH OTHER WEAK PIECES OF ENERGY
IN THE NORTHWEST FLOW ALOFT. THE SOUTHERN SHORTWAVE TROF IS
STRONGER AND MAINTAINS IT`S STRENGTH ACROSS KANSAS. SHOULD SEE
SOME CONVECTIVE DEBRIS WITH THESE SYSTEMS THIS MORNING. ALTHOUGH
DYNAMICS ARE WEAK...THETA-E ADVECTION CONTINUES DURING THE MORNING
AND EARLY AFTERNOON ALONG WITH MID LEVEL MOISTURE. WILL MENTION
ISOLATED SHOWERS ACROSS PARTS OF THE SOUTH THIS MORNING WITH A FEW
SPRINKLES FARTHER NORTH...AND COULD SEE AND ISOLATED SHOWER IN THE
NORTH THIS AFTERNOON AND EVENING. WITH THE VARIABLE
CLOUDS...TEMPERATURES COULD BE HELD DOWN...BUT FOR NOW HAVE HIGHS
IN THE MID TO UPPER 80S.
A MUCH STRONGER FRONT WILL MOVE INTO THE FORECAST AREA WEDNESDAY
AFTERNOON. THE LOW LEVEL JET STRENGTHENS TONIGHT AND CONTINUES
INTO WED NIGHT. INSTABILITY AND SHEAR INCREASE WITH THE
APPROACHING FRONT ALONG WITH DEEPER MOISTURE RETURN.
FRONTOGENESIS...UVV...AND STEEP LAPSE RATES ALL SUPPORT THE CHC
FOR SCT THUNDERSTORMS. HAVE MAINTAINED HIGH CHC POPS FOR MOST OF
THE AREA TO LIKELY POPS FOR THE NORTHEAST...WITH INCREASING CHANCE
FOR STORMS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...LINGERING
INTO THURSDAY MORNING. HIGHS WEDNESDAY SHOULD TOP OUT IN THE 90S.
SURFACE HIGH PRESSURE WILL BUILD IN LATER THURSDAY AND FRIDAY WITH
COOLER HIGH TEMPERATURES IN THE 70S AND LOWS IN THE 40S AND 50S.
THE FORECAST INTO THE WEEKEND REMAINS COOL WITH HIGHS IN THE 70S
AND LOWER 80S. THERE COULD BE SOME STORMS SATURDAY WITH A WEAK
FRONTAL PASSAGE.
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
HAVE CONTINUED TAF FORECASTS FOR VFR CONDITIONS...THE HIGHEST
PROBABILITY OCCURRENCE...BUT THERE REMAINS A LOW
PROBABILITY/CONFIDENCE ISSUE REGARDING FOG. SOME PATCHY FOG
IS POSSIBLE OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA WITH
SATURATION ALREADY REPORTED AT KICL AT 04Z. HOWEVER WITH
INCREASING MID CLOUD CIGS EXPECTED TO SPREAD INTO THE AREA AND
GROUND SURFACE QUITE DRY FROM LACK OF RAIN HAVE KEPT FOG OUT AT
TAF SITES. UPSTREAM CONVECTION OVER WRN SOUTH DAKOTA EXPECTED TO
STAY WEST OF TAF SITES BASED ON EVENING MODEL RUN.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
415 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 11 AM THIS MORNING/...
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLANE AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /11 AM THIS MORNING THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
130 AM UPDATE...
VFR CONDS EXPECTED AT ALL TERMINALS WITH EXCEPTION OF KELM EARLY
THIS MORNING. BKN-OVC100 CIGS ACRS KSYR/KRME WITH SKC FURTHER
SOUTH. AREA OF LIGHT SHOWERS MOVING ACROSS WESTERN NY AT THIS
MOMENT MAY MAKE IT INTO TERMINALS THIS MORNING BUT CONFIDENCE NOT
HIGH ENOUGH TO MENTION IN TERMINAL FORECASTS. HOWEVER GROWING AREA
OF RAIN ACROSS SOUTHERN PA MAY IMPACT KAVP BTWN 12Z-14Z AND HAVE
THROWN IN TEMPO MENTION TO THIS TERMINAL.
WITH CLEAR SKIES AND LIGHT WINDS AT KELM...MAY SEE BRIEF MVFR VSBY
RESTRICTIONS THROUGH 09Z BEFORE OVC DECK MOVES IN. BY AFTERNOON
EXPECT -SHRA TO DEVELOP ALL TERMINALS AFTER 18Z WITH SOME TSTMS
EXPECTED...HOWEVER CONFIDENCE REMAINS LOW ON TIMING AND SPECIFIC
TERMINALS TO BE IMPACTED.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
354 AM CDT TUE AUG 14 2012
.SHORT TERM...
PRECIP CHANCE FOR TONIGHT AND TOMORROW AND TEMPERATURES THURSDAY
WILL BE THE PRIMARY FORECAST CHALLENGES FOR THE PERIOD.
WV LOOP AND UPPER AIR ANALYSIS SHOW NORTHWESTERLY FLOW ALOFT WITH
SIGNS OF AN EMBEDDED WEAK SHORTWAVE OVER THE NORTHERN PLAINS...BUT
THE MAIN UPPER SYSTEM IS STILL DIGGING INTO BRITISH COLUMBIA. THE
THE NAM AND RAP ALONG WITH THE HRRR HAVE SOME LIGHT PRECIP
ENTERING OUR CWA THIS MORNING AS THE WEAK SHORTWAVE MOVES
THROUGH...WHILE THE LARGER SCALE MODELS STAY DRY. THERE HAS BEEN
SOME RADAR RETURNS OVER BIS...BUT THEY HAVE PRODUCED ONLY A VERY
SMALL AMOUNT OF RAIN AND SEEM TO BE ON A DOWNWARD TREND. WILL
MONITOR THROUGH THE NEXT HOUR OR SO IN CASE SOME SPRINKLES NEED TO
BE ADDED TO THE SOUTHWESTERN CWA THIS MORNING...BUT DO NOT THINK
WE WILL SEE ANYTHING MEASURABLE.
HIGH PRESSURE WILL MOVE OFF TO THE EAST TODAY...WITH SOUTHERLY
WINDS STARTING TO PICK UP OVER THE WESTERN CWA AS THE SFC LOW
DEVELOPS OVER EASTERN MT. HIGHS SHOULD BE A BIT WARMER THAN
YESTERDAY. TONIGHT...THE UPPER TROUGH WILL BEGIN TO DIG INTO MT
FROM CANADA...WHICH SHOULD HELP PUSH THE SFC LOW OUT INTO THE
PLAINS. THERE ARE SOME VARIATIONS AS TO HOW MUCH PRECIP BREAKS OUT
TONIGHT IN THE WARM AIR ADVECTION ON THE FRONT SIDE OF THE SYSTEM.
NAM AND GFS ARE IN FAIRLY DECENT AGREEMENT ON SOME DEVELOPMENT
OVER THE SOUTHERN COUNTIES OVERNIGHT...SO CONCENTRATED THE HIGHEST
POPS IN THAT AREA THIS EVENING WITH HIGHS POPS AFTER MIDNIGHT AS
THE SYSTEM CONTINUES TO MOVE CLOSER.
THE UPPER TROUGH WILL DIG INTO THE DAKOTAS ON WEDNESDAY...AND MUCH
DEPENDS ON THE EXACT TIMING OF THE UPPER SYSTEM AND ASSOCIATED
COLD FRONT...AND THE MODELS CONTINUE TO STRUGGLE WITH THIS. THE
NAM IS NOW SLOWER THAN THE GFS...WITH THE FRONT THROUGH MOST OF
THE COUNTIES BY MID DAY BUT IT SHOULD REACH THE SOUTHEAST BY PEAK
HEATING AND THE NAM SHOWS SOME DECENT INSTABILITY. THE GFS IS
FASTER AND HAS THE FRONT THROUGH ALL BUT THE FAR EASTERN EDGE BY
00Z THURSDAY. MEANWHILE...THE ECMWF IS SLOWER WITH THE UPPER
SYSTEM AND CONTINUES TO SHOW LINGERING PRECIP OVER THE EASTERN
COUNTIES THROUGH EARLY THURSDAY MORNING. ECMWF SEEMS TO HAVE MORE
INTERNAL CONSISTENCY...WITH THE NAM AND GFS DOING A LOT OF FLIP
FLOPPING. STILL A LOT OF UNCERTAINTY AS TO THE TIMING. IN THE
INTERESTS OF INTERSITE CONSISTENCY...CONTINUED TO KEEP LIKELY POPS
IN THE EASTERN COUNTIES FOR WEDNESDAY AFTERNOON AND EVENING WITH
SOME EVEN LINGERING AFTER MIDNIGHT IN THE FAR EASTERN COUNTIES.
AFTER THE COLD FRONT MOVES THROUGH...850MB TEMPS WILL BE IN THE
SINGLE DIGITS C AND WITH THE COLD POOL ALOFT...THERE WILL BE A
FAIR AMOUNT OF CLOUDS LINGERING AND EVEN SOME SHOWERS IN THE
NORTHEASTERN COUNTIES INTO THURSDAY. KEPT HIGHS IN THE 60S FOR
THURSDAY...AND WITH THE SFC HIGH NEARBY INTO THURSDAY NIGHT AND
DEW POINTS AROUND 40 F...LOWS THURSDAY NIGHT COULD BE QUITE COOL
IN THE LOW TO MID 40S.
.LONG TERM (FRI-MON)...
MODELS IN GOOD AGREEMENT WITH 500MB NORTHWEST FLOW...A VERY TYPICAL
EARLY FALL REGIME IN THE EXTENDED PERIOD. THIS WILL BRING
QUIET...READ DRY...WEATHER WITH SEASONABLY COOL TEMPS TO THE
NORTHERN PLAINS FOR THE UPCOMING WEEKEND. THE 500MB RIDGING ACROSS
THE INTERMOUNTAIN WEST WILL SLOWLY BEGIN TO WORK ITS WAY
EAST...REALIZING A GRADUAL INCREASE OF TEMPS FROM FRIDAY TO
MONDAY.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AS MID AND UPPER
LEVEL CLOUDS INCREASE. LIGHT WINDS WILL INCREASE OUT OF THE
SOUTHEAST AFTER 18Z AS LOW PRESSURE DEVELOPS TO THE WEST.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR/JK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
120 AM CDT TUE AUG 14 2012
.DISCUSSION...
EMBEDDED S/WV IMPULSE CONTINUES TO SLIDE EAST-SOUTHEAST ACROSS
WESTERN SOUTH DAKOTA. ASSOCIATED PRECIPITATION WITH THIS FEATURE
MAINLY TO OUR SOUTH. AREA OF LINGERING LIGHT SHOWERS OVER SOUTH
CENTRAL NORTH DAKOTA EXPECTED TO DIMINISH NOW THROUGH 9-10Z AS
FORCING DECREASES WITH THE DEPARTURE OF THE WAVE. WILL MAINTAIN
SLIGHT CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS WEST AND
CENTRAL THROUGH 12Z WITH MODELS DEPICTING SEVERAL WEAK WAVES IN
NORTHWEST FLOW ALOFT TRACKING ACROSS THE REGION. ALSO...SOUTHERLY
LLJ DEVELOPING OVER MY WEST WILL MIGRATE EAST INTO CENTRAL ND NOW
THROUGH 18Z. 00Z GFS/NAM ALONG WITH THE HRRR AND 4KM WRF ALL
GENERATE SHOWERS/POSSIBLE THUNDER WEST INTO CENTRAL THROUGH
12Z...WITH MODELS FOCUSING ON MY NORTHWEST AND NORTH CENTRAL WHERE
THE NOSE OF LLJ IS DEPICTED.
LINGERING PRECIPITATION LOOKS POSSIBLE 12-18Z TUESDAY MORNING OVER
MY CENTRAL AND EASTERN COUNTIES UNTIL THE LLJ WANES MID TO LATE
MORNING. DRY CONDITIONS FORECAST WEST. MODIFIED THE GRIDDED
FORECAST TO REFLECT THE ABOVE SCENARIO.
&&
.AVIATION...AT 11 PM CDT...A WARM FRONT EXTENDED ACROSS EASTERN
MONTANA INTO SOUTHWEST SOUTH DAKOTA. THE FRONT IS FORECAST TO MOVE
EAST INTO WESTERN NORTH DAKOTA TUESDAY AFTERNOON. AN AREA OF SHOWERS
IS DIMINISHING ACROSS SOUTHWEST NORTH DAKOTA. WITH RECENT RAINS
ADDED A MENTION OF 3 MILES IN LIGHT FOG/MIST ACROSS KDIK BETWEEN 09
AND 12Z. THERE IS SOME UNCERTAINTY IN WHETHER THIS WILL
HAPPEN...SO USED A TEMPO...AND KEPT IT LOW VFR. ELSEWHERE ALL TAF
SITES WILL BE VFR THROUGH THE 06Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1143 PM CDT MON AUG 13 2012
.DISCUSSION...
UPDATED FOR 06Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 226 PM CDT MON AUG 13 2012/
MORNING CONVECTION HAS MOVED EAST OF THE MIDSOUTH AS EXPECTED
WITH PARTIAL SUNSHINE SPREADING OVER THE AREA FROM THE WEST.
MEANWHILE...A COLD FRONT IS PUSHING INTO NORTHEAST ARKANSAS AND
STRETCHES SOUTHWESTWARD INTO NORTHEAST TX. THE FRONT HAS MOVED
THROUGH WALNUT RIDGE ARKANSAS AND IS APPROACHING JONESBORO.
STILL THINK THERE IS A CHANCE OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON INTO THIS EVENING ALONG AND AHEAD OF THE COLD
FRONT...ALTHOUGH THE SITUATION IS NOT CLEAR CUT. WATER VAPOR IMAGERY
INDICATES THE MAIN UPPER LEVEL TROUGH IS MOVING EAST OF THE MIDSOUTH
WITH UPPER LEVEL SUPPORT NOW LIMITED ACROSS OUR FORECAST AREA. WATER
VAPOR IMAGERY IS ALSO SHOWING VERY DRY AIR ALOFT MOVING INTO OUR
FORECAST AREA. HOWEVER...VERY WARM AND UNSTABLE AIR IS PUSHING INTO
THE AREA AHEAD OF THE FRONT ON SOUTHWEST SURFACE WINDS. TEMPERATURES
IN NORTHEAST AND EAST CENTRAL AR ARE MOVING INTO THE LOWER 90S AND
SURFACE BASED CAPES HAVE INCREASED TO BETWEEN 2000 AND 2500 J/KG AND
LIFTED INDICES HAVE DECREASED TO ABOUT MINUS 6.
LATEST HIGH RESOLUTION RAPID REFRESH (HRRR) MODEL INDICATES THAT
SCATTERED SHOWERS AND THUNDERSTORMS WILL BEGIN TO FORM ALONG THE
COLD FRONT BY 3 OR 4 PM...THEN BECOME A LITTLE BETTER ORGANIZED AS
THE STORMS MOVE EAST OF THE MS RIVER BY LATE AFTERNOON AND EVENING.
MODELS CONTINUE TO INDICATE THE ATMOSPHERE WILL BECOME QUITE
UNSTABLE AHEAD OF THE FRONT WITH SURFACE BASED CAPES INCREASING TO
BETWEEN 32000 AND 4200 J/KG WITH LIFTED INDICES DECREASING TO MINUS
8. ALTHOUGH...THE HRRR MODEL INDICATES THE STORMS WILL STRUGGLE IN
COVERAGE WITH SUCH DRY AIR ALOFT LIMITING THE MOISTURE.
ALTHOUGH...THE DRY AIR ALOFT WILL ENHANCE THE DOWNDRAFT POTENTIAL
WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE IN THE STRONGER STORMS.
LARGE HAIL IS ALSO POSSIBLE.
THE COLD FRONT IS FORECAST NEAR THE MS RIVER BY LATE
AFTERNOON...THEN WILL MOVE SOUTHEASTWARD THROUGH THE MIDSOUTH
TONIGHT. THINK THE SEVERE WEATHER THREAT WILL END BY LATE EVENING.
NOT MUCH CHANGE TO THE EARLIER FORECAST CONCERNING TUESDAY THROUGH
THE WEEKEND. HIGH PRESSURE AND DRIER AIR WILL SPREAD OVER THE
MIDSOUTH TUESDAY INTO WEDNESDAY ALLOWING FOR GOOD DIURNAL SPREADS IN
TEMPERATURES WITH RELATIVELY COOL NIGHTS AND VERY WARM AFTERNOONS.
A WARM FRONT IS FORECAST TO PUSH THROUGH THE MIDSOUTH THURSDAY WITH
VERY UNSTABLE AND MOIST AIR SPREADING BACK OVER THE AREA. THIS WILL
CAUSE A CHANCE OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL
APPROACH FROM THE NORTHWEST THURSDAY NIGHT AND MOVE SLOWLY THROUGH
THE REGION FRIDAY INCREASING THE THREAT OF SHOWERS AND
THUNDERSTORMS. THERE WILL BE A LINGERING CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS EAST CENTRAL ARKANSAS AND NORTH MS SATURDAY BUT
OTHERWISE KEPT WITH A RAINFREE FORECAST FOR THE WEEKEND INTO NEXT
MONDAY. HOWEVER...THERE IS SOME QUESTION HOW FAR THE COLD FRONT WILL
SETTLE SOUTHWARD BECOMING STALLING...SO SOME CHANCE OF SHOWERS AND
THUNDERSTORMS COULD LINGER ACROSS EAST CENTRAL AR AND NORTH MS INTO
SUNDAY.
JCL
&&
.AVIATION...
06Z TAF CYCLE
SHRAS AND TSRAS HAVE PUSHED WELL EAST OF THE COLD FRONT THAT IS
SLOWLY MOVING ACROSS THE MIDSOUTH. AT 04Z THE FRONT WAS LOCATED
JUST EAST OF A KDYR-KMEM-KUTA LINE. GENERALLY VFR CONDS EXPECTED
OVER THE NEXT FEW HOURS THOUGH SOME LIGHT FOG IS POSSIBLE AT KMKL
AND KTUP. DRIER AIR HAS MOVED INTO KJBR AND IS FILTERING INTO
KMEM SO FOG THREAT IS MINIMAL AT THOSE LOCATIONS. EXPECT LOW
CLOUDS TO MOVE SOUTH AND DEVELOP ACROSS THE AREA LATE TONIGHT SO
ADDED TEMPOS FOR MVFR CIGS AT ALL SITES BTWN 14/11Z AND 14/15Z.
IFR CIGS POSSIBLE IN KMKL. CIGS WILL GRADUALLY LIFT AND BECOME VFR
DURING THE DAY. WINDS WILL GENERALLY BE LIGHT OVERNIGHT INCREASE
TO NORTH AT 7-10 TUESDAY MORNING.
SJM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 69 88 68 93 / 10 0 10 10
MKL 65 86 59 90 / 30 10 10 10
JBR 63 87 62 92 / 10 0 10 10
TUP 70 89 65 91 / 50 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
205 AM EDT TUE AUG 14 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXIT THE REGION TONIGHT AND MAKE WAY FOR AN
APPROACHING COLD FRONT. THIS FRONT WILL MOVE THROUGH THE REGION
TOMORROW EVENING. IN ITS WAKE...HIGH PRESSURE WILL RETURN TO THE
REGION WITH YET ANOTHER...AND PERHAPS STRONGER...COLD FRONT SLATED
TO CROSS THE REGION FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 115 AM EDT TUESDAY...
INCREASING LOW AND MID LEVEL MOISTURE AND WEAK FORCING ASSOCIATED
WITH WEAK SHORT WAVE TROF MOVING NORTHEAST THROUGH THE AREA
RESULTING IN EXPANDING AREA OF SHOWERS ALONG AND WEST OF THE BLUE
RIDGE. NAM MODEL DEPICTING THIS QUITE WELL...AND GENERALLY
FOLLOWED FOR THE REST OF TONIGHT...GRADUALLY MOVING AREA OF BEST
FORCING AND ASSOCIATED WIDESPREAD SHOWERS INTO AND THEN OUT OF EXTREME
NORTHERN AND WESTERN COUNTIES BY LATE TONIGHT...WITH
PRECIPITATION ENDING ACROSS THE SOUTHWESTERN COUNTIES. ISSUED
UPDATE TO HOURLY GRIDS TO REFLECT THE TIMING AND TRANSIT OF HIGHER
PRECIPITATION PROBABILITIES ACROSS THE MOUNTAINS FOR THE OVERNIGHT
PERIOD...AND TWEAKED HOURLY TEMPERATURES AND DEW POINTS A BIT TO
REFLECT CURRENT AND ANTICIPATED TRENDS FOR THE REST OF THE NIGHT.
OTHERWISE...LEFT REST OF GRID PACKAGE UNCHANGED.
AS OF 855 PM EDT MONDAY...
MOISTURE GRADUALLY RETURNING TO THE AREA TONIGHT WITH EVENING
RAOBS SHOWING ONLY A DRY LAYER REMAINING IN THE BOUNDARY LAYER AND
ANOTHER SMALL CAPPED POCKET ALOFT. INITIAL RESIDUAL BAND OF SHRA
WELL AHEAD OF THE FRONT ALONG THE MISS RIVER HAS BASICALLY FADED
CROSSING THE FAR WESTERN RIDGES BUT HAS ALLOWED FOR SOME INCREASE
IN WEAK INSTABILITY AS DEW POINTS START TO SLOWLY CREEP UP. APPEARS
WITH THIS TREND CONTINUING OVERNIGHT THAT MAY SEE ISOLATED SHRA
AFFECT THE WEST...THEN PERHAPS A BAND OR TWO LATE SPCLY NW
SECTIONS AS THE PRE-FRONTAL ZONE APPROACHES TOWARD MORNING PER THE
LATEST HRRR. THUS MADE ONLY SMALL ADJUSTS TO THE EARLIER EVENING
UPDATE WITH A SCATTERING OF 20ISH POPS PAST MIDNIGHT...THEN A BIT
HIGHER CHANCE WEST LATE. OTRW PLENTY OF CLOUDS AROUND TO MAKE
TEMPS A LITTLE MORE TRICKY AS THINGS BECOME MORE HUMID OVERNIGHT.
THINK SOME DEGREE OF CLOUDINESS WILL LINGER THEREFORE BUMPED UP LOWS A
FEW DEGREES TO THE WARM SIDE OF MOS INCLUDING THE LATEST LAV.
AS OF 612 PM EDT MONDAY...
EARLY EVENING UPDATE MAINLY TO REDUCE POPS ACROSS THE SW THIS
EVENING GIVEN MAIN AXIS OF SHRA PASSING TO THE SW...AND THEN TO
INCLUDE SOME CHANCE POPS AFTER MIDNIGHT ACROSS THE WEST PER SHRA
DEVELOPMENT BEHIND THE PRE-FRONTAL RH LOBE ATTM. THIS SUPPORTED
VIA THE LATEST HRRR WHICH BRINGS SOME OF THIS LEFTOVER CONVECTION
INTO THE WESTERN ZONES LATE IN CONJUNCTION WITH MOISTENING OF MID
LEVELS OFF LATEST FORECAST RAOBS. ALSO LOWERED TEMPS SOME OVER THE
SW WHERE HEATING WAS LESS DUE TO EARLY ARRIVAL OF THE MID DECK
CANOPY.
AS OF 315 PM EDT MONDAY...
INFLUENCE OF HIGH PRESSURE WILL CONTINUE THROUGH THIS EVENING.
PRECIPITATION WILL BE VERY LIMITED...IF EXISTS AT ALL. THE GREAT
POTENTIAL WILL BE ALONG THE CREST OF THE BLUE RIDGE SOUTHWEST OF
FLOYD INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA...AND IN AREAS
ALONG AND NEAR THE NC/VA BORDER.
OVERNIGHT...MID TO HIGH LEVEL CLOUD COVER IS EXPECTED TO OVERSPREAD
THE REGION AS DEBRIS CLOUD COVER FROM AN APPROACHING COLD FRONT
ADVECTS INTO THE REGION. THIS WILL HAVE THE RESULT OF
LIMITED...ALTHOUGH NOT COMPLETELY PREVENTING...THE DEVELOPMENT OF
PRIMARILY LATE NIGHT MOUNTAIN VALLEY FOG...ESPECIALLY OVER PARTS OF
THE GREENBRIER AND NEW RIVER VALLEYS. SOME ISOLATED TO SCATTERED
SHOWERS WILL BE POSSIBLE OVER SOUTHEAST WEST VIRGINIA BY SUNRISE IN
ASSOCIATION WITH THE APPROACHING FRONT.
ON TUESDAY...THE FRONT WILL DRAW EVEN CLOSE TO THE REGION DURING THE
DAY TUESDAY. ISENTROPIC LIFT IN ADVANCE OF THE FRONT WILL HELP TO
PROVIDE GENEROUS COVERAGE OF SHOWERS AND STORMS BY MIDDAY ACROSS ALL
BUT THE FAR EASTERN SECTIONS OF THE REGION. BY THE LATE
AFTERNOON...ALL AREAS ARE EXPECTED TO HAVE AT LEAST SCATTERED
COVERAGE OF SHOWERS AND STORMS...WITH THE GREATEST COVERAGE ACROSS
SOUTHEAST WEST VIRGINIA AND AREAS ALONG AND NEAR THE CREST OF THE
BLUE RIDGE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 112 PM EDT MONDAY...
JUST SOME MINOR TWEAKS TO THE PREVIOUS FORECAST FOR THIS TIME
PERIOD. MODELS SHOW A DECENT SHORTWAVE SHIFTING EAST ACROSS THE ARE
TUE NIGHT INTO WED MORNING...SO EXPECT TO SEE LINGERING SHOWERS OR
STORMS IN THE EAST TUE EVENING AND SOME UPSLOPE ENHANCE SHOWERS
ACROSS THE MTNS INTO WED MORNING BEFORE SUBSIDENCE STARTS TO DRY THE
COLUMN OUT SUBSTANTIALLY. THE UPPER FLOW STAYS IN A GENERAL WRLY
DIRECTION AFTER THE FRONTAL PASSAGE AND ONLY EXPECTING MEAGER DROPS
IN THE DEW POINTS WITH TEMPS REMAINING JUST AS WARM AS TUESDAY.
A WEAK HIGH PRESSURE SYSTEM LINGERS ACROSS THE AREA INTO THURSDAY
DURING WHICH SKIES SHOULD REMAIN CLEAR-PARTLY CLOUDY.
SHOULD SEE INCREASING CLOUDS AHEAD OF NEXT TROUGH AND SFC FRONT LATE
THU NIGHT...BUT ANY PRECIP SHOULD HOLD OFF UNTIL FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 112 PM EDT MONDAY...
POSITIVE PNA PATTERN WITH TROUGH IN THE EASTERN U.S./TROUGH WEST
COAST WILL BE THE UPPER AIR FLOW INTO THE EXTENDED PERIOD WITH SOME
BREAKDOWN IN THE WRN RIDGE AFTER NEXT MONDAY.
THE NEXT FRONT WILL SLIDE INTO THE AREA FRIDAY INTO SATURDAY. UPPER
PATTERN SUPPORTS SLOWER MOVEMENT OF FRONT AND COULD SEE THE FRONT
STALL JUST SOUTH AND EAST OF THE FORECAST AREA OVER THE WEEKEND. THE
ECMWF ALLUDES TO MORE CLOUDS ACROSS THE SRN CWA INTO SUNDAY WITH AN
INCREASE IN PRECIP CHANCES HEADING INTO MONDAY ACROSS SRN VA/NRN NC.
FOR NOW WILL KEEP THE AREA DRY MONDAY...PER HPC AND ENSEMBLE
LEANINGS...GIVEN THE TROUGH DOES LOOK TO DEEPEN JUST ENOUGH.
SO FOR THIS PERIOD...THINK AT LEAST A CHANCE POPS WARRANTED FRI-SAT
WITH SOME DRYING ACROSS THE REGION SAT NIGHT-SUN WITH A FEW
LINGERING SHOWERS IN THE PIEDMONT...THEN MAINLY DRY WITH INCREASING
CLOUDS AROUND SUN NIGHT INTO MONDAY ACROSS THE PIEDMONT SOUTHWEST
INTO THE NC FOOTHILLS.
TEMPS THIS PERIOD SHOULD COOL OFF AGAIN TOWARD WHAT WE HAD THIS PAST
WEEKEND WITH HIGHS IN THE 70S WEST TO LOWER 80S EAST...WHILE LOWS AT
NIGHT RANGE FROM THE LOWER 50S WEST TO LOWER 60S EAST.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 200 AM EDT TUESDAY...
AREA OF SHOWERS ALONG AND WEST OF THE BLUE RIDGE WITH AREAS OF
MVFR RESTRICTIONS...AND EVEN SOME LOCALIZED IFR CONCERNS OVER/NEAR
SOME OF THE HIGHER RIDGES WILL GRADUALLY LIFT NORTH OF BATH COUNTY
VA BEFORE DAYBREAK WITH PASSAGE OF WEAK SHORT WAVE TROF. SOME
REDEVELOPMENT OF SOME FOG WITH IFR/LIFR RESTRICTIONS IN SOME MOUNTAIN
VALLEYS THAT RECEIVED RAIN WILL BE POSSIBLE UNTIL AN HOUR OR TWO
AFTER DAYBREAK...BUT NO DIRECT IMPACT EXPECTED TO ANY TERMINAL
FORECAST POINT AT THE PRESENT TIME.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ALONG AND IN
ADVANCE OF NEXT COOL FRONT EXPECTED TO BEGIN TO IMPACT WESTERN
TERMINAL FORECAST POINTS (KLWB AND KBLF) AS A PREVAILING CONDITION
BY OR SHORTLY AFTER NOON ON TUESDAY...WITH EVENT EXPECTED TO BE MORE
SCATTERED IN NATURE DURING THE AFTERNOON FOR POINTS FURTHER EAST
(KBCB...KROA...KLYH...KDAN)...WHERE VCTS REMARKS HAVE BEEN
INSERTED. ALTHOUGH SOME LOCALIZED MVFR OR EVEN IFR FLIGHT
RESTRICTIONS ARE POSSIBLE IN SOME OF THE STRONGER STORMS...MOST
AREAS SHOULD MAINTAIN VFR WEATHER ON TUESDAY DESPITE THE THREAT OF
PRECIPITATION.
OTHERWISE...OTHER THAN LOCALIZED FLIGHT RESTRICTIONS IN
AFTERNOON/EVENING SHOWERS/STORMS...AND WITH ADDITIONAL LOCALIZED
RESTRICTIONS DUE TO PATCHY LATE NIGHT/EARLY MORNING FOG IN
MOUNTAIN VALLEYS AND LOW LYING SECTIONS THAT RECEIVE RAIN...MAINLY
VFR WEATHER IS EXPECTED TO HOLD FOR MOST TERMINAL FORECAST POINTS
THROUGH THE UPCOMING WEEK.
&&
.EQUIPMENT...
THE NOAA WEATHER RADIO FROM ROANOKE VIRGINIA IS OFF THE AIR
TONIGHT LIKELY DUE TO A PHONE PROBLEM. RETURN TO SERVICE TIME IS
UNKNOWN AS TECHNICIANS WORK ON THE PROBLEM.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS/JH/WERT
SHORT TERM...WP
LONG TERM...WP
AVIATION...WERT
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1038 AM EDT TUE AUG 14 2012
.SYNOPSIS...
AN UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH
THE AREA FROM THE WEST TODAY. THE FRONT WILL BECOME DIFFUSE IN THE
FORECAST AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EXPECT A CONTINUED WEAKENING TREND WITH THE SHOWERS MOVING INTO
THE AREA FROM THE WEST THIS MORNING BECAUSE OF THE DRY AIR MASS IN
PLACE. THESE SHOWERS ARE ASSOCIATED WITH CONVERGENCE AHEAD OF THE
COLD FRONT AND A MID-LEVEL SHORTWAVE TROUGH. THE LATEST RAP SHOWS
THE SHORTWAVE TROUGH WILL BE SHIFTING EAST OF THE FORECAST AREA
THIS AFTERNOON...BUT INCREASED LOW-LEVEL MOISTURE AHEAD OF THE
FRONT AND DIURNAL HEATING SHOULD RESULT IN SCATTERED
THUNDERSTORMS. CLOUDINESS AND THE UPPER-LEVEL LIFT SHIFTING EAST
OF THE FORECAST AREA DURING THE AFTERNOON SHOULD LIMIT
INSTABILITY. THE NAM INDICATES MAINLY WEAK INSTABILITY WITH
AFTERNOON SURFACE LI/S NEAR -5. THE ACTIVITY COULD LINGER INTO
THE EVENING AND POSSIBLY THE OVERNIGHT HOURS BECAUSE OF CONTINUED
CONVERGENCE ASSOCIATED WITH THE WEAK FRONT AND POSSIBLY ANOTHER
MID-LEVEL SHORTWAVE TROUGH. HOWEVER...WE HAVE FORECASTED LOW POPS
BECAUSE OF THE LOSS OF HEATING AND THIS IS ALSO SUPPORTED BY THE
NAM AND GFS MOS GUIDANCE. EXPECT TEMPERATURES NEAR CLIMATOLOGY
WITH HIGHS TODAY NEAR 90 AND LOWS TONIGHT IN THE LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE UPPER TROUGH WILL CONTINUE TO MOVE SLOWLY EAST
ACROSS THE REGION. AT THE SURFACE...MODELS INDICATE THAT THE FRONT
WILL PUSH INTO THE FORECAST AREA AND BECOME DIFFUSE. THE SPC HAS
THE AREA IN A SEE TEXT WITH A MENTION THAT THIS AREA COULD BE
UPGRADED TO A SLIGHT RISK. MODEL TIME SECTIONS SHOW THE AIR MASS
ON WEDNESDAY WILL BECOME MODERATELY UNSTABLE WITH CAPE VALUES
APPROACHING 2000 J/KG...TT AROUND 50 AND LI/S BETWEEN -3 AND -6.
ALSO PRECIPITABLE WATER VALUES WILL BE AROUND 1.8 INCHES. A FEW
OF THE STORMS COULD BECOME STRONG WITH GUSTY WINDS AND LOCALLY
HEAVY RAIN. THE STORMS SHOULD BE MOVING ENOUGH TO PREVENT ANY
SIGNIFICANT FLOODING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
ACROSS THE EASTERN MIDLANDS ALONG AND AHEAD OF THE FRONTAL
BOUNDARY. BY WEDNESDAY NIGHT INTO THURSDAY...THE TROUGH AXIS WILL
MOVE EAST OF THE AREA. WEAK HIGH PRESSURE IS EXPECTED TO BUILD
INTO THE REGION FOR THURSDAY/THU NIGHT. GUIDANCE AND LOCAL NUMBERS
REASONABLY CLOSE THROUGH THE PERIOD AND HAVE STAYED NEAR CONSENSUS
FOR TEMPERATURES AND POPS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
UPPER FLOW BECOMES MORE ZONAL FRIDAY. A LONG-WAVE TROUGH THEN
BEGINS TO DEEPEN WITH ITS AXIS JUST TO THE WEST OF THE APPALACHIAN
MOUNTAINS SATURDAY THROUGH MONDAY. AN INCREASE IN LOW-LEVEL
MOISTURE IS EXPECTED TO YIELD A 20 TO 40 PERCENT CHANCE OF MAINLY
AFTERNOON AND EVENING CONVECTIVE ACTIVITY FRIDAY THROUGH MONDAY.
MAX TEMPERATURES AROUND 90 SHOULD BE THE RULE FRIDAY...BUT COOLING
DOWN SLIGHTLY INTO THE WEEKEND AS THE TROUGH DEVELOPS ACROSS THE
EASTERN HALF OF THE COUNTRY. MORE CLOUDS SATURDAY THROUGH MONDAY
WILL PROBABLY KEEP HIGHS IN THE MIDDLE/UPPER 80S. OVERNIGHT LOWS
IN THE MIDDLE/UPPER 60S TO LOWER 70S FOR MOST OF THE PERIOD.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
UPPER TROUGH SWINGING ACROSS THE TENNESSEE VALLEY RESULTING IN
CONVECTION OVER GEORGIA WITH VFR CIGS AROUND 6000 FT AHEAD OF THE
CONVECTION OVERSPREADING THE TERMINALS. SOME MVFR VSBYS IN FOG
POSSIBLE AT OGB 12Z-13Z. WILL INCLUDE VCSH AGS/DNL 13Z-15Z AND
CAE/CUB 15Z-17Z ALTHOUGH DO NOT EXPECT RESTRICTIONS.
A COLD FRONT WILL PUSH INTO THE AREA LATER THIS AFTERNOON BUT DEEP
MOISTURE IS LIMITED AS WELL AS INSTABILITY SO CONFIDENCE IS LOW FOR
TIMING CONVECTION AND COVERAGE SHOULD BE WIDELY SCATTERED. EXPECT
CUMULUS ALONG WITH A HIGHER CEILING DUE TO UPSTREAM CONVECTIVE
DEBRIS ADVECTING EASTWARD. WINDS WILL GENERALLY BE CALM THROUGH
SUNRISE THEN INCREASE TO AROUND 10 MPH FROM THE SOUTHWEST...THEN
BECOME LIGHT AFTER SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
800 AM EDT TUE AUG 14 2012
.SYNOPSIS...
AN UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH
THE AREA FROM THE WEST TODAY. THE FRONT WILL BECOME DIFFUSE IN THE
FORECAST AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EXPECT A CONTINUED WEAKENING TREND WITH THE SHOWERS MOVING INTO
THE AREA FROM THE WEST THIS MORNING BECAUSE OF THE DRY AIR MASS IN
PLACE. THESE SHOWERS ARE ASSOCIATED WITH CONVERGENCE AHEAD OF THE
COLD FRONT AND A MID-LEVEL SHORTWAVE TROUGH. THE LATEST RAP SHOWS
THE SHORTWAVE TROUGH WILL BE SHIFTING EAST OF THE FORECAST AREA
THIS AFTERNOON...BUT INCREASED LOW-LEVEL MOISTURE AHEAD OF THE
FRONT AND DIURNAL HEATING SHOULD RESULT IN SCATTERED
THUNDERSTORMS. CLOUDINESS AND THE UPPER-LEVEL LIFT SHIFTING EAST
OF THE FORECAST AREA DURING THE AFTERNOON SHOULD LIMIT
INSTABILITY. THE NAM INDICATES MAINLY WEAK INSTABILITY WITH
AFTERNOON SURFACE LI/S NEAR -5. THE THREAT OF SEVERE WEATHER
APPEARS LOW. THE ACTIVITY COULD LINGER INTO THE EVENING AND
POSSIBLY THE OVERNIGHT HOURS BECAUSE OF CONTINUED CONVERGENCE
ASSOCIATED WITH THE WEAK FRONT AND POSSIBLY ANOTHER MID-LEVEL
SHORTWAVE TROUGH. HOWEVER...WE HAVE FORECASTED LOW POPS BECAUSE OF
THE LOSS OF HEATING AND THIS IS ALSO SUPPORTED BY THE NAM AND GFS
MOS GUIDANCE. EXPECT TEMPERATURES NEAR CLIMATOLOGY WITH HIGHS
TODAY NEAR 90 AND LOWS TONIGHT IN THE LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE UPPER TROUGH WILL CONTINUE TO MOVE SLOWLY EAST
ACROSS THE REGION. AT THE SURFACE...MODELS INDICATE THAT THE FRONT
WILL PUSH INTO THE FORECAST AREA AND BECOME DIFFUSE. THE SPC HAS
THE AREA IN A SEE TEXT WITH A MENTION THAT THIS AREA COULD BE
UPGRADED TO A SLIGHT RISK. MODEL TIME SECTIONS SHOW THE AIR MASS
ON WEDNESDAY WILL BECOME MODERATELY UNSTABLE WITH CAPE VALUES
APPROACHING 2000 J/KG...TT AROUND 50 AND LI/S BETWEEN -3 AND -6.
ALSO PRECIPITABLE WATER VALUES WILL BE AROUND 1.8 INCHES. A FEW
OF THE STORMS COULD BECOME STRONG WITH GUSTY WINDS AND LOCALLY
HEAVY RAIN. THE STORMS SHOULD BE MOVING ENOUGH TO PREVENT ANY
SIGNIFICANT FLOODING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
ACROSS THE EASTERN MIDLANDS ALONG AND AHEAD OF THE FRONTAL
BOUNDARY. BY WEDNESDAY NIGHT INTO THURSDAY...THE TROUGH AXIS WILL
MOVE EAST OF THE AREA. WEAK HIGH PRESSURE IS EXPECTED TO BUILD
INTO THE REGION FOR THURSDAY/THU NIGHT. GUIDANCE AND LOCAL NUMBERS
REASONABLY CLOSE THROUGH THE PERIOD AND HAVE STAYED NEAR CONSENSUS
FOR TEMPERATURES AND POPS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
UPPER FLOW BECOMES MORE ZONAL FRIDAY. A LONG-WAVE TROUGH THEN
BEGINS TO DEEPEN WITH ITS AXIS JUST TO THE WEST OF THE APPALACHIAN
MOUNTAINS SATURDAY THROUGH MONDAY. AN INCREASE IN LOW-LEVEL
MOISTURE IS EXPECTED TO YIELD A 20 TO 40 PERCENT CHANCE OF MAINLY
AFTERNOON AND EVENING CONVECTIVE ACTIVITY FRIDAY THROUGH MONDAY.
MAX TEMPERATURES AROUND 90 SHOULD BE THE RULE FRIDAY...BUT COOLING
DOWN SLIGHTLY INTO THE WEEKEND AS THE TROUGH DEVELOPS ACROSS THE
EASTERN HALF OF THE COUNTRY. MORE CLOUDS SATURDAY THROUGH MONDAY
WILL PROBABLY KEEP HIGHS IN THE MIDDLE/UPPER 80S. OVERNIGHT LOWS
IN THE MIDDLE/UPPER 60S TO LOWER 70S FOR MOST OF THE PERIOD.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
UPPER TROUGH SWINGING ACROSS THE TENNESSEE VALLEY RESULTING IN
CONVECTION OVER GEORGIA WITH VFR CIGS AROUND 6000 FT AHEAD OF THE
CONVECTION OVERSPREADING THE TERMINALS. SOME MVFR VSBYS IN FOG
POSSIBLE AT OGB 12Z-13Z. WILL INCLUDE VCSH AGS/DNL 13Z-15Z AND
CAE/CUB 15Z-17Z ALTHOUGH DO NOT EXPECT RESTRICTIONS.
A COLD FRONT WILL PUSH INTO THE AREA LATER THIS AFTERNOON BUT DEEP
MOISTURE IS LIMITED AS WELL AS INSTABILITY SO CONFIDENCE IS LOW FOR
TIMING CONVECTION AND COVERAGE SHOULD BE WIDELY SCATTERED. EXPECT
CUMULUS ALONG WITH A HIGHER CEILING DUE TO UPSTREAM CONVECTIVE
DEBRIS ADVECTING EASTWARD. WINDS WILL GENERALLY BE CALM THROUGH
SUNRISE THEN INCREASE TO AROUND 10 MPH FROM THE SOUTHWEST...THEN
BECOME LIGHT AFTER SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
739 AM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT
STRETCHES FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION...
HAS SPARKED CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND
WEST CENTRAL GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS
HOLD THIS CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS
INTO THE ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER...
CANNOT RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING
HOURS. EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND
SOUTH BUT WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT...
CURRENTLY ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER
THIS AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND
OF CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
.AVIATION...
12Z UPDATE...
AN UPPER DISTURBANCE IS SPARKING THUNDERSTORMS OVER EAST CENTRAL AL
THIS MORNING. TIMING TOOL INDICATES TSTMS WILL PUSH ACROSS THE
ATLANTA AREA TAF SITES BETWEEN 13-15Z THIS MORNING. MAY SEE BRIEF
MVFR CIGS WITH THE HEAVIER CONVECTION... BUT EXPECT MID LEVEL VFR
CIGS TO PREVAIL. A FRONTAL BOUNDARY WILL PUSH INTO NW GA LATER THIS
AFTERNOON WITH SCATTERED CONVECTION DEVELOPING OUT AHEAD DURING MAX
HEATING. MODELS AGREE THIS TSTM ACTIVITY WILL PUSH ACROSS THE
ATLANTA TAF SITES DURING THE LATE AFTERNOON OR EARLY EVENING HOURS.
OTHERWISE... LIGHT SW WINDS THIS MORNING WILL INCREASE TO AROUND
8-10KTS BY 15-16Z...THEN BECOME MORE WESTERLY THIS EVENING AND
OVERNIGHT AHEAD OF AN APPROACHING COLD FRONT. WET GROUNDS AHEAD OF
THE COLD FRONT WILL RESULT IN IFR CIGS BY 09Z TONIGHT. THE DRIER NW
FLOW BEHIND THE COLD FRONT SHOULD CLEAR LOW CLOUDS OUT BY 13-14Z WED.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM TO HIGH ON ALL ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....20
AVIATION...39
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
636 AM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE, COMING EAST FROM INDIANA, WILL BRING SHOWERS AND
SCATTERED THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY UNTIL THE
LOW PASSES THROUGH THIS EVENING. HIGH PRESSURE FROM IOWA WILL
FOLLOW WITH DRY SEASONABLE CONDITIONS WEDNESDAY AND THURSDAY. A
COLD FRONT, COMING SOUTHEAST FROM MONTANA, WILL PROVIDE THE NEXT
ROUND OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE ADJUSTED SHOWER CHANCES FOR THE EARLY MORNING. BASED ON
RECENT RADAR AND SURFACE DATA PLUS HRRR MODEL OUTPUT, THE FIRST
BATCH OF ISOLATED SHOWERS HAS EXITED EAST OF THE MOUNTAINS. HAVE
ADDED ISOLATED FOG PATCHES THROUGH 9 AM.
BLEND OF RECENT WRF-NMM, HRRR, AND SREF MODEL OUTPUT THEN SHOW
CURRENT RADAR-DEPICTED SHOWERS AND ISOLATED THUNDERSTORMS OVER
WESTERN OHIO, WILL INCREASE IN COVERAGE LATER THIS MORNING AND
THROUGH THE AFTERNOON, AS THEY SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE CENTER, MOVING EAST FROM INDIANA.
HAVE LOW EXPECTATIONS REGARDING SEVERE POTENTIAL, AS NAM-MODEL
PROFILES AND MOST SREF MODEL MEMBERS SHOW INSTABILITY ACROSS THE
UPPER OHIO VALLEY WILL LIMITED BY THICKENING CLOUDS THIS MORNING.
THERE WILL BE MORE INSTABILITY AND HENCE MORE SEVERE POTENTIAL
EAST OF THE MOUNTAINS.
THIS SCENARIO IS FORTUNATE FOR THE UPPER OHIO VALLEY AS VERTICAL
WIND SHEAR, THAT IS, EFFECTIVE BULK SHEARS OF 30 PLUS KNOTS, WOULD
HAVE BEEN SUFFICIENT TO ORGANIZE RISING AIR COLUMNS INTO PRODUCING
SEVERE POTENTIAL.
AS LOW PRESSURE SYSTEM EXITS EAST TONIGHT, SHOWERS WILL END WEST
TO EAST LATE. DUE TO NOCTURNAL-COOLING OF A RAIN-MOISTENED SURFACE
LAYER, PATCHY FOG CAN DEVELOP.
FORECASTED TEMPERATURES TO BE SLIGHTLY COOLER THAN NORMAL TODAY,
THEN NEAR NORMAL TONIGHT, AS INDICATED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
BLEND OF SREF AND GFS MODEL OUTPUT SHOW HIGH PRESSURE COMING EAST
FROM IOWA WILL PROVIDE DRYING AND SUBSIDENCE ACROSS THE UPPER OHIO
VALLEY WEDNESDAY AND THURSDAY. DO REALIZE THERE WILL BE A TRAILING
TROUGH ALOFT WEDNESDAY THAT COULD SET OFF ISOLATED SHOWERS, BUT
CONCUR WITH GFS AND NAM MOS THAT PROBABILITIES WILL BE TOO LOW TO
MENTION.
A STRONGER LOW PRESSURE SYSTEM WILL MOVE EASTWARD ACROSS SOUTHERN
CANADA DURING THIS PERIOD, WHICH WILL PUSH A COLD FRONT THROUGH
THE UPPER OHIO VALLEY FRIDAY. SO HAVE ADDED A CHANCE OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY NIGHT AND FRIDAY.
FORECASTED TEMPERATURES TO BE NEAR SEASONABLE LEVELS BASED ON
RECENT GFS AND NAM MOS AND SREF MEAN VALUES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
POST-COLD FRONTAL 850 TEMPS OF 6-7C, WITH A COLD TROUGH ALOFT
PASSING THROUGH THE UPPER OHIO VALLEY, MAY CONTINUE CLOUDS AND
SCATTERED SHOWERS THROUGH DAYTIME SATURDAY. FORECASTED
TEMPERATURES TO BE ABOUT 5 DEGREES COOLER THAN NORMAL.
ENSUING HIGH PRESSURE WILL PROVIDE DRY BUT COOLER THAN NORMAL
TEMPERATURES SUNDAY AND MONDAY, JUDGING FROM RECENT GFS AND ECMWF
MOS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
ISOLATED FOG PATCHES CAN PROVIDE MVFR VISIBILITIES THROUGH 13Z.
THEN VFR CONDITIONS WILL PERSIST UNTIL RAIN SHOWERS AND
SCATTERED THUNDERSTORMS SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE SYSTEM, THAT WILL CROSS THE REGION LATE THIS AFTERNOON,
AND EXIT EAST EARLY TONIGHT. MVFR CIGS AND VIS CAN BE EXPECTED
ESPECIALLY IN ANY THUNDERSTORMS BUT WITH LIMITED CONFIDENCE IN
TSRA COVERAGE AT THIS POINT WILL LEAVE IT OUT OF TAFS.
PATCHES OF FOG, WITH MAINLY MVFR RESTRICTIONS, CAN DEVELOP
TONIGHT DUE TO NOCTURNAL COOLING OF A RAIN-MOISTENED SURFACE
LAYER. THE DEGREE TO WHICH RESTRICTIONS WILL DEVELOP WILL BE
HIGHLY DEPENDENT ON AMOUNT OF RAINFALL THAT ACTUALLY OCCURS
TODAY.
.OUTLOOK...WEDNESDAY THROUGH SATURDAY...
EXPECT VFR WEDNESDAY AND THURSDAY DUE TO PASSING HIGH PRESSURE.
THE NEXT POSSIBILITY OF RESTRICTIONS WILL BE FRIDAY INTO SATURDAY
DUE TO SHOWERS AND STORMS ASSOCIATED WITH A COLD FRONTAL PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1057 AM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 406 AM EDT TUE AUG 14 2012
AFTER A MORNING OF AREAS OF DENSE FOG AND SCATTERED RAIN
SHOWERS...MUCH OF THE AREA WILL SEE CLEARING SKIES THIS AFTERNOON.
MUCH OF THE REGION WILL SEE DRY CONDITIONS TONIGHT THROUGH
WEDNESDAY NIGHT AS HIGH PRESSURE MOVES THROUGH. THE CHANCE OF RAIN
WILL COME THURSDAY AS A STRONG COLD FRONT PUSHES THROUGH. MUCH
COOLER WEATHER IS EXPECTED BY THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 1058 AM EDT TUE AUG 14 2012
I EXPUNGED THE FOG FROM OUR GRIDS AND UPDATED OUR ZONE FORECAST TO
DROP ANY REFERENCE TO THE FOG. CURIOUS HOW THE LOW CLOUDS ARE
MIXING OUT MORE QUICKLY ALONG INTERSTATE 96 THEN ELSEWHERE... SO I
TRENDED THE CLOUD GRID THAT WAY. THAT IS I HAVE MORE CLOUDS NORTH
AND SOUTH OF INTERSTATE 96 INTO EARLY AFTERNOON TO ALLOW FOR THE
CLOUDS THAT ARE THERE TO MIX OUT.
A WEAK SHORTWAVE... AS SEEN ON THE RAP DATA AND ALSO SEEN ON THE
WATER VAPOR LOOP... MAY TOUCH OFF AN ISOLATED THUNDERSTORM OVER
OUR NE CWA THIS AFTERNOON. THE SOUNDING DO SHOW CAPES TO NEAR 1000
J/KG AND THE TQ INDEX RISES TO NEAR 25C WHICH IS WELL ABOVE THE
15C THRESHOLD FOR THUNDERSTORM. PROBLEM IS THERE IS VERY LITTLE
MOISTURE IN THE SOUNDINGS BETWEEN 10,000 AND 20,000 FT SO ANY CU
TOWERS THAT WOULD DEVELOP WILL HAVE TO STRUGGLE WITH THE DRY AIR
ENTRAINMENT. EVEN SO I PUT 20 POPS THIS AFTERNOON FOR THAT AREA.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
WILL GO WITH A DENSE FOG ADVISORY FOR NW AREAS OF THE CWA. THIS
AREA HAS SEEN THE MID LEVEL CLOUDS PEEL AWAY AND FOG IS DEVELOPING
UNDER THE CLEAR SKIES. OTHERWISE THE FEW LEFTOVER SHOWER IN THE
EASTERN CWA SHOULD BE CLEARING OUT THE OF CWA BY LATE MORNING.
EXPECT A FAIRLY RAPID CLEARING BEHIND THE SHOWERS INTO THE AFTERNOON.
QUIET WEATHER EXPECTED TONIGHT THROUGH WEDNESDAY NIGHT. TEMPS WILL
REBOUND TO 80 TO 85 FOR WEDNESDAY AS WE BEGIN TO SEE RETURN FLOW
AROUND A SURFACE HIGH.
CURRENT TIMING OF THE COLD FRONT ON THURSDAY MAY DIMINISH A SEVERE
THREAT. MODELS SUGGEST IT WILL PASS THROUGH EARLY AFTERNOON WITH
PLENTY OF CLOUDS AND SHOWERS AHEAD OF IT. THIS MAKES THE
OPPORTUNITY TO BECOME UNSTABLE QUESTIONABLE. EVEN SO...WE SHOULD
SEE A GOOD CHANCE OF SHOWERS AND A FEW STORMS...SO EXPANDED THE
LIKELY POPS OVER ALL OF THE CWA.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
A COLD FRONT WILL PUSH SOUTH OF THE AREA THURSDAY NIGHT...USHERING
IN A COOL FALL LIKE AIR MASS FOR THE WEEKEND. MAIN POINTS OF
CONTENTION IN THE LONG TERM ARE PRECIP CHANCES AND CHANCES FOR
STRONGER STORMS THURSDAY NIGHT...AND UPPER LOW SHOWER POTENTIAL OVER
THE WEEKEND.
COLD FRONT SHOULD BISECT THE FORECAST AREA FROM NORTHEAST TO
SOUTHWEST THURSDAY EVENING WITH SHOWERS AND THUNDERSTORMS ACROSS THE
CWA. BEST CHANCES WILL LIKELY BE ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. PRECIPITATION WILL LIKELY MOVE SOUTH OF THE AREA BY
FRIDAY MORNING. AS FOR THREAT OF STRONG STORMS...FEEL BETTER
INSTABILITY WILL BE JUST SOUTH AND EAST OF THE FORECAST AREA
THURSDAY NIGHT.
ENVISION DIURNALLY DRIVEN SHOWERS OVER THE WEEKEND WITH AN UPPER LOW
OVERHEAD. LOW LEVEL MOISTURE OFF THE GREAT LAKES WILL LIKELY ADD TO
THE INSTABILITY THAT WILL BE IN PLACE DUE TO THE COLD MID LEVELS.
GFS AND ECMWF STILL AT ODDS OVER A SHORTWAVE AND SURFACE TROUGH THAT
THE GFS SWINGS THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY. HAVE
20 POPS IN THE FORECAST AT THIS POINT UNTIL BETTER AGREEMENT OCCURS.
BOTTOM LINE CONTINUES TO BE A FALL LIKE FEEL FOR LATE IN THE WEEK
AND THE WEEKEND...AS HIGHS AROUND 70 FRI/SAT ONLY WARM TO THE LOW TO
MID 70S SUN/MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 741 AM EDT TUE AUG 14 2012
DEEPER MOISTURE IS MOVING EAST OF THE AREA THIS MORNING ALLOWING
FOG TO FORM IN ITS WAKE. LIFR CONDITIONS HAVE DEVELOPED ACROSS
MUCH OF THE AREA WHERE THE DEEPER MOISTURE HAS EXITED TO THE EAST.
THE LIFR CONDITIONS SHOULD LIFT RATHER QUICKLY THIS MORNING THOUGH
AS THE MOISTURE IS QUITE SHALLOW. BY 15Z...MOST AREAS SHOULD BE
VFR.
SCATTERED TO OCCASIONALLY BROKEN CUMULUS CLOUDS CAN BE EXPECTED
THROUGH THE BULK OF THE DAY...DISSIPATING WITH THE SETTING SUN.
OVERNIGHT...EXPECTING VFR CONDITIONS TO PREVAIL. THERE IS THE
POTENTIAL FOR SOME FOG ONCE AGAIN AFTER 08Z...BUT NOT AS WIDESPREAD.
AT THIS POINT LEFT THE FOG OUT OF THE FORECAST GIVEN LOW
CONFIDENCE.
&&
.MARINE...
ISSUED AT 406 AM EDT TUE AUG 14 2012
LIGHT WINDS AND LOW WAVES WILL BE THE SEEN THROUGH WEDNESDAY.
HOWEVER SOUTHERN WINDS WILL BE RAMPING UP WEDNESDAY NIGHT AND
THURSDAY...AHEAD AND AS THE FRONT COMES THROUGH. WE MAY APPROACH
SCA CONDITIONS LATE WEDNESDAY NIGHT/EARLY THURSDAY...BUT THERE
WILL BE EVEN STRONG WINDS IN THE CAA BEHIND THE FRONT BY THE END
OF THE WEEK.
&&
.HYDROLOGY...
ISSUED AT 406 AM EDT TUE AUG 14 2012
NEXT DECENT CHANCE OF RAIN WILL COME THURSDAY/THURSDAY NIGHT WITH
A STRONG COLD FRONT. MANY AREAS SHOULD SEE AROUND A HALF INCH OF
RAIN...WITH LOCALIZED HIGHER AMOUNTS. THIS SHOULD NOT CAUSE ANY
WIDESPREAD HYDRO CONCERNS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
632 AM CDT TUE AUG 14 2012
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
EXPECT VFR CONDITIONS THROUGH THE NEXT 24 HOURS. VARIABLE AMOUNTS
OF CLOUDINESS WILL OCCUR...WITH ANY CEILINGS FORECAST TO BE AT OR
ABOVE 9000 FEET. ALTHOUGH SOME ISOLATED -TSRA MAY OCCUR...FELT THE
CHANCE WAS LOW ENOUGH TO LEAVE OUT OF TAFS FOR NOW. SOUTHERLY
WINDS SHOULD INCREASE INTO THE 11-15 KNOT RANGE TODAY...THEN BE
IN THE 7-11 KNOT RANGE TONIGHT.
MILLER
&&
.PREV DISCUSSION... /ISSUED 351 AM CDT TUE AUG 14 2012/
DISCUSSION...
FORECAST CONCERNS EARLY ON WILL BE ANY LINGERING PRECIPITATION AND
CLOUDS TODAY...THEN PRECIPITATION CHANCES TONIGHT AND BETTER
CHANCES FOR RAIN WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
THE 00Z H5 PATTERN HAD THE CENTRAL PLAINS UNDER NORTHWEST FLOW ALOFT
WITH A COUPLE OF EMBEDDED SHORTWAVES. AT 04Z...THE SHORTWAVE OVER
MONTANA HAD ALREADY PUSHED INTO THE DAKOTAS...AND THE SHORTWAVE OVER
COLORADO WAS ADVANCING INTO WRN KANSAS. THE 00Z 80KT H3 JET WAS OVER
NEBRASKA AND THERE WAS SOME DECENT UPR LEVEL DIVERGENCE OVER
COLORADO. THE H85 THETA-E AXIS AXIS AT 06Z WAS OVER THE WESTERN
PLAINS WITH H85 WINDS PER THE VWPS FM THE SOUTH AT AROUND 30 TO
35KTS. STEEP MID LEVEL LAPSE RATES OF 7 TO 8.5 DEG C/KM WERE ALSO IN
THIS REGION. BY 08Z...THE LAST WSR-88D RADAR MOSAIC HAD SOME
SHOWERS AND THUNDERSTORMS FROM THE CNTRL DAKOTAS BACK TOWARD WRN
NEBRASKA...A FEW ECHOES IN CENTRAL AND EASTERN NEBRASKA THAT HAD
WEAKENED FROM EARLIER THIS AM...AND A MORE ORGANIZED AREA OF
PRECIPITATION OVER KANSAS. AN EARLIER RUN OF THE HRRR DID NOT
PICK UP ON THE TSRA FOR CENTRAL NEBRASKA AND THE LATEST RUN IS
DOING A BETTER JOB...WITH A CONTINUED WEAKENING TREND AS THE
STORMS MOVE EAST.
THIS MORNING...THE LOW LEVEL JET IS PROGGED TO CONTINUE FROM 30 TO
35KTS FROM THE WCNTRL DAKOTAS INTO CNTRL NEBRASKA...SOUTH INTO
WRN AND CNTRL KANSAS WITH SOME VEERING DURING THE MORNING. THE
TRENDS ON THE IR SATELLITE WEAKENING AND THE NORTHERN WAVE REMAINS
WEAK AS IT MOVES THRU THE PLAINS WITH OTHER WEAK PIECES OF ENERGY
IN THE NORTHWEST FLOW ALOFT. THE SOUTHERN SHORTWAVE TROF IS
STRONGER AND MAINTAINS IT`S STRENGTH ACROSS KANSAS. SHOULD SEE
SOME CONVECTIVE DEBRIS WITH THESE SYSTEMS THIS MORNING. ALTHOUGH
DYNAMICS ARE WEAK...THETA-E ADVECTION CONTINUES DURING THE MORNING
AND EARLY AFTERNOON ALONG WITH MID LEVEL MOISTURE. WILL MENTION
ISOLATED SHOWERS ACROSS PARTS OF THE SOUTH THIS MORNING WITH A FEW
SPRINKLES FARTHER NORTH...AND COULD SEE AND ISOLATED SHOWER IN THE
NORTH THIS AFTERNOON AND EVENING. WITH THE VARIABLE
CLOUDS...TEMPERATURES COULD BE HELD DOWN...BUT FOR NOW HAVE HIGHS
IN THE MID TO UPPER 80S.
A MUCH STRONGER FRONT WILL MOVE INTO THE FORECAST AREA WEDNESDAY
AFTERNOON. THE LOW LEVEL JET STRENGTHENS TONIGHT AND CONTINUES
INTO WED NIGHT. INSTABILITY AND SHEAR INCREASE WITH THE
APPROACHING FRONT ALONG WITH DEEPER MOISTURE RETURN.
FRONTOGENESIS...UVV...AND STEEP LAPSE RATES ALL SUPPORT THE CHC
FOR SCT THUNDERSTORMS. HAVE MAINTAINED HIGH CHC POPS FOR MOST OF
THE AREA TO LIKELY POPS FOR THE NORTHEAST...WITH INCREASING CHANCE
FOR STORMS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...LINGERING
INTO THURSDAY MORNING. HIGHS WEDNESDAY SHOULD TOP OUT IN THE 90S.
SURFACE HIGH PRESSURE WILL BUILD IN LATER THURSDAY AND FRIDAY WITH
COOLER HIGH TEMPERATURES IN THE 70S AND LOWS IN THE 40S AND 50S.
THE FORECAST INTO THE WEEKEND REMAINS COOL WITH HIGHS IN THE 70S
AND LOWER 80S. THERE COULD BE SOME STORMS SATURDAY WITH A WEAK
FRONTAL PASSAGE.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1027 AM EDT TUE AUG 14 2012
.SYNOPSIS...
TODAY THROUGH WEDNESDAY, LOW PRESSURE WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS WESTERN NEW YORK AND THEN INTO SOUTHERN
QUEBEC. THIS SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS TO THE
AREA PRIMARILY THIS AFTERNOON AND EVENING. UNSETTLED WEATHER WILL
CONTINUE THROUGH WEDNESDAY BEFORE HIGH PRESSURE BRINGS DRY AND
SEASONAL CONDITIONS ON THURSDAY. ANOTHER COLD FRONT WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
10 AM UPDATE...AREA OF SHOWERS AND ISOLATED THUNDERSTORMS NOW
DEPARTING THE WESTERN CATSKILLS AND POCONOS AS MID LEVEL SHORT
WAVE AND WEAK ISENTROPIC LIFT SHIFTS EAST. SATELLITE SHOWS
CLEARING SKIES ACROSS WESTERN NY AND INTO THE CENTRAL SOUTHERN
TIER. THIS AREA OF CLEARING IS EXPECTED TO MAKE PROGRESS ACROSS
THE FINGER LAKES REGION INTO THE LAKE PLAIN AND PARTS OF THE
SOUTHERN TIER. THIS WILL DESTABILIZE THE ATMOSPHERE PRIOR TO THE
NEXT MORE WIDESPREAD ROUND OF SHOWERS AND THUNDERSTORMS AS SFC LOW
TRACKS INTO WESTERN NEW YORK. CONVECTION WILL INCREASE LATER THIS
AFTERNOON INTO THE EVENING WITH STILL THE THREAT THAT A FEW MAY
BECOME SEVERE. JUST MINOR ADJUSTMENTS TO SHORT TERM POPS/CLOUDS/TEMPS.
.PREVIOUS DISC...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST
OF THE AREA BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY
SEVERE POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE
OF THESE SHOWERS THROUGH MID- AFTERNOON... BEFORE ANOTHER WAVE
ROTATING AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF
CONVECTION LATER THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME
CLEARING IS OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT
THIS POINT EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR
AREA THIS AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE
RANGE OF POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR
1000 J/KG. NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE
THIS AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT
WITH DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH
TO PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO
THIS EVENING. HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT
APPEARS TO BE LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN
ASSOCIATION WITH A WEAK... POORLY ORGANIZED SURFACE LOW... AND
MID-TO-UPPER LEVEL HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL
OF THE ABOVE REASONING EXPECT A FEW STRONG TO MARGINALLY SEVERE
STORMS TO DEVELOP LATER THIS AFTERNOON WITH ISOLATED SEVERE
REPORTS LIKELY BUT NOT A WIDESPREAD EVENT. SPC HAS THE SOUTHERN
HALF OF OUR AREA IN A SLIGHT RISK OF SEVERE WEATHER TODAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE/RRM
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
653 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATED AT 630 AM... HAVE UPDATED GRIDS BASED ON LATEST TRENDS.
AREA OF RAIN CONTINUES TO MOVE FROM CENTRAL TO NORTHEAST PA AND
HAVE INCREASED POPS TO 80 PERCENT OR GREATER TO COVER FOR THE
EXPECTED MOVEMENT OF THIS SYSTEM ACROSS NORTHEAST PA THROUGH ABOUT
9 AM. CONVECTIVE TREND WITH THIS SYSTEM HAS BEEN TOWARD WEAKENING
DURING THE PAST HOUR. DOPPLER RADAR ESTIMATES INDICATED OVER AN INCH
OF RAIN OVER A SMALL AREA WEST OF LUZERNE COUNTY... BUT RAIN RATES
AND LIGHTNING HAVE ALL DIMINISHED SINCE 5 AM. FARTHER NORTH RADAR
TRENDS INDICATE THAT JUST WIDELY SCATTERED SHOWERS OR STORMS CAN
BE EXPECTED THROUGH THE REST OF THIS MORNING. PREVIOUS DISCUSSION
BELOW.
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLAIN AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
644 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATED AT 630 AM... HAVE UPDATED GRIDS BASED ON LATEST TRENDS.
AREA OF RAIN CONTINUES TO MOVE FROM CENTRAL TO NORTHEAST PA AND
HAVE INCREASED POPS TO 80 PERCENT OR GREATER TO COVER FOR THE
EXPECTED MOVEMENT OF THIS SYSTEM ACROSS NORTHEAST PA THROUGH ABOUT
9 AM. CONVECTIVE TREND WITH THIS SYSTEM HAS BEEN TOWARD WEAKENING
DURING THE PAST HOUR. DOPPLER RADAR ESTIMATES INDICATED OVER AN INCH
OF RAIN OVER A SMALL AREA WEST OF LUZERNE COUNTY... BUT RAIN RATES
AND LIGHTNING HAVE ALL DIMINISHED SINCE 5 AM. FARTHER NORTH RADAR
TRENDS INDICATE THAT JUST WIDELY SCATTERED SHOWERS OR STORMS CAN
BE EXPECTED THROUGH THE REST OF THIS MORNING. PREVIOUS DISCUSSION
BELOW.
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLANE AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
638 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATED AT 630 AM... HAVE UPDATED GRIDS BASED ON LATEST TRENDS.
AREA OF RAIN CONTINUES TO MOVE FROM CENTRAL TO NORTHEAST PA AND
HAVE INCREASED POPS TO 80 PERCENT OR GREATER TO COVER FOR THE
EXPECTED MOVEMENT OF THIS SYSTEM ACROSS NORTHEAST PA THROUGH ABOUT
9 AM. CONVECTIVE TREND WITH THIS SYSTEM HAS BEEN TOWARD WEAKENING
DURING THE PAST HOUR. DOPPLER RADAR ESTIMATES INDICATED OVER AN INCH
OF RAIN OVER A SMALL AREA WEST OF LUZERNE COUNTY... BUT RAIN RATES
AND LIGHTNING HAVE ALL DIMINISHED SINCE 5 AM. FARTHER NORTH RADAR
TRENDS INDICATE THAT JUST WIDELY SCATTERED SHOWERS OR STORMS CAN
BE EXPECTED THROUGH THE REST OF THIS MORNING. PREVIOUS DISCUSSION
BELOW.
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLANE AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
130 AM UPDATE...
VFR CONDS EXPECTED AT ALL TERMINALS WITH EXCEPTION OF KELM EARLY
THIS MORNING. BKN-OVC100 CIGS ACRS KSYR/KRME WITH SKC FURTHER
SOUTH. AREA OF LIGHT SHOWERS MOVING ACROSS WESTERN NY AT THIS
MOMENT MAY MAKE IT INTO TERMINALS THIS MORNING BUT CONFIDENCE NOT
HIGH ENOUGH TO MENTION IN TERMINAL FORECASTS. HOWEVER GROWING AREA
OF RAIN ACROSS SOUTHERN PA MAY IMPACT KAVP BTWN 12Z-14Z AND HAVE
THROWN IN TEMPO MENTION TO THIS TERMINAL.
WITH CLEAR SKIES AND LIGHT WINDS AT KELM...MAY SEE BRIEF MVFR VSBY
RESTRICTIONS THROUGH 09Z BEFORE OVC DECK MOVES IN. BY AFTERNOON
EXPECT -SHRA TO DEVELOP ALL TERMINALS AFTER 18Z WITH SOME TSTMS
EXPECTED...HOWEVER CONFIDENCE REMAINS LOW ON TIMING AND SPECIFIC
TERMINALS TO BE IMPACTED.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
935 AM CDT TUE AUG 14 2012
.DISCUSSION...
UPDATED TO INCREASE CLOUD COVER A LITTLE ACROSS THE SOUTH THRU THE
MORNING. MAIN CHALLENGE IS HOW FAST THESE CLOUDS SHIFT OFF TO THE
EAST. WILL LOWER TEMPS A FEW DEGREES IN THE SOUTH BUT THINK IT
SHOULD SCATTER OUT LATER AND ALLOW TEMPS TO REBOUND QUICKLY.
EXPANDED THE MENTION OF SPRINKLES A LITTLE FURTHER TO THE EAST AS
WELL.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AS MID AND UPPER
LEVEL CLOUDS INCREASE. LIGHT WINDS WILL INCREASE OUT OF THE
SOUTHEAST AFTER 18Z AS LOW PRESSURE DEVELOPS TO THE WEST.
&&
.PREV DISCUSSION... /ISSUED 354 AM CDT TUE AUG 14 2012/
SHORT TERM...
PRECIP CHANCE FOR TONIGHT AND TOMORROW AND TEMPERATURES THURSDAY
WILL BE THE PRIMARY FORECAST CHALLENGES FOR THE PERIOD.
WV LOOP AND UPPER AIR ANALYSIS SHOW NORTHWESTERLY FLOW ALOFT WITH
SIGNS OF AN EMBEDDED WEAK SHORTWAVE OVER THE NORTHERN PLAINS...BUT
THE MAIN UPPER SYSTEM IS STILL DIGGING INTO BRITISH COLUMBIA. THE
THE NAM AND RAP ALONG WITH THE HRRR HAVE SOME LIGHT PRECIP
ENTERING OUR CWA THIS MORNING AS THE WEAK SHORTWAVE MOVES
THROUGH...WHILE THE LARGER SCALE MODELS STAY DRY. THERE HAS BEEN
SOME RADAR RETURNS OVER BIS...BUT THEY HAVE PRODUCED ONLY A VERY
SMALL AMOUNT OF RAIN AND SEEM TO BE ON A DOWNWARD TREND. WILL
MONITOR THROUGH THE NEXT HOUR OR SO IN CASE SOME SPRINKLES NEED TO
BE ADDED TO THE SOUTHWESTERN CWA THIS MORNING...BUT DO NOT THINK
WE WILL SEE ANYTHING MEASURABLE.
HIGH PRESSURE WILL MOVE OFF TO THE EAST TODAY...WITH SOUTHERLY
WINDS STARTING TO PICK UP OVER THE WESTERN CWA AS THE SFC LOW
DEVELOPS OVER EASTERN MT. HIGHS SHOULD BE A BIT WARMER THAN
YESTERDAY. TONIGHT...THE UPPER TROUGH WILL BEGIN TO DIG INTO MT
FROM CANADA...WHICH SHOULD HELP PUSH THE SFC LOW OUT INTO THE
PLAINS. THERE ARE SOME VARIATIONS AS TO HOW MUCH PRECIP BREAKS OUT
TONIGHT IN THE WARM AIR ADVECTION ON THE FRONT SIDE OF THE SYSTEM.
NAM AND GFS ARE IN FAIRLY DECENT AGREEMENT ON SOME DEVELOPMENT
OVER THE SOUTHERN COUNTIES OVERNIGHT...SO CONCENTRATED THE HIGHEST
POPS IN THAT AREA THIS EVENING WITH HIGHS POPS AFTER MIDNIGHT AS
THE SYSTEM CONTINUES TO MOVE CLOSER.
THE UPPER TROUGH WILL DIG INTO THE DAKOTAS ON WEDNESDAY...AND MUCH
DEPENDS ON THE EXACT TIMING OF THE UPPER SYSTEM AND ASSOCIATED
COLD FRONT...AND THE MODELS CONTINUE TO STRUGGLE WITH THIS. THE
NAM IS NOW SLOWER THAN THE GFS...WITH THE FRONT THROUGH MOST OF
THE COUNTIES BY MID DAY BUT IT SHOULD REACH THE SOUTHEAST BY PEAK
HEATING AND THE NAM SHOWS SOME DECENT INSTABILITY. THE GFS IS
FASTER AND HAS THE FRONT THROUGH ALL BUT THE FAR EASTERN EDGE BY
00Z THURSDAY. MEANWHILE...THE ECMWF IS SLOWER WITH THE UPPER
SYSTEM AND CONTINUES TO SHOW LINGERING PRECIP OVER THE EASTERN
COUNTIES THROUGH EARLY THURSDAY MORNING. ECMWF SEEMS TO HAVE MORE
INTERNAL CONSISTENCY...WITH THE NAM AND GFS DOING A LOT OF FLIP
FLOPPING. STILL A LOT OF UNCERTAINTY AS TO THE TIMING. IN THE
INTERESTS OF INTERSITE CONSISTENCY...CONTINUED TO KEEP LIKELY POPS
IN THE EASTERN COUNTIES FOR WEDNESDAY AFTERNOON AND EVENING WITH
SOME EVEN LINGERING AFTER MIDNIGHT IN THE FAR EASTERN COUNTIES.
AFTER THE COLD FRONT MOVES THROUGH...850MB TEMPS WILL BE IN THE
SINGLE DIGITS C AND WITH THE COLD POOL ALOFT...THERE WILL BE A
FAIR AMOUNT OF CLOUDS LINGERING AND EVEN SOME SHOWERS IN THE
NORTHEASTERN COUNTIES INTO THURSDAY. KEPT HIGHS IN THE 60S FOR
THURSDAY...AND WITH THE SFC HIGH NEARBY INTO THURSDAY NIGHT AND
DEW POINTS AROUND 40 F...LOWS THURSDAY NIGHT COULD BE QUITE COOL
IN THE LOW TO MID 40S.
LONG TERM (FRI-MON)...
MODELS IN GOOD AGREEMENT WITH 500MB NORTHWEST FLOW...A VERY TYPICAL
EARLY FALL REGIME IN THE EXTENDED PERIOD. THIS WILL BRING
QUIET...READ DRY...WEATHER WITH SEASONABLY COOL TEMPS TO THE
NORTHERN PLAINS FOR THE UPCOMING WEEKEND. THE 500MB RIDGING ACROSS
THE INTERMOUNTAIN WEST WILL SLOWLY BEGIN TO WORK ITS WAY
EAST...REALIZING A GRADUAL INCREASE OF TEMPS FROM FRIDAY TO
MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1037 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER BRIEFLY BEFORE THE NEXT COLD
FRONT MOVES ACROSS THE CAROLINAS LATE FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM...A BIT OF A COMPLICATED FCST FOR THIS MORNING UPDATE.
THE WATER VAPOR LOOP AND RAP SHOW A SERIES OF VORT MAXIMA ROUNDING
THE MEAN UPR TROF AXIS...WITH ONE OF THEM PROGGED TO CROSS THE CWFA
THIS AFTN/EVE. MEANWHILE...AS WEAK SFC LOW WAS ANALYZED INVOF OH
WITH A COLD FRONT EXTENDING SOUTH ACRS THE TN VLY TO THE SRN PLAINS.
VISIBLE SAT IMAGERY SHOWS COPIOUS CLOUD COVER FROM LAST NIGHT/S
CONVECTION...WITH A REMNANT COLD POOL ACRS ERN TN/N GA AND WRN HALF
OF THE CWFA.
SO THE MAIN CHALLENGE TODAY IS TIMING AND COVERAGE OF CONVECTION AND
WHAT SEVERE THREAT WE MAY HAVE. SPC HAS EXPANDED THE NEW DAY1
CONVECTIVE OUTLOOK TO INCLUDE THE ENTIRE CWFA. THE THINKING IS THAT
WITH 25-30 KTS OF 0-6 KM BULK SHEAR AND DPVA FROM AFOREMENTIONED S/W
ENERGY...ANY CLEARING OF CLOUDS WILL ALLOW ENUF DESTABILIZATION FOR
AT LEAST SCATTERED STORMS DEVELOPING WITHIN THE WARM SECTOR ALONG
AND AHEAD OF THE COLD FRONT AND BECOMING LOOSELY ORGANIZED INTO
MULTI-CELL CLUSTERS. SO WITH THIS UPDATE...I WILL PUSH BACK THE
HIGHER POPS UNTIL MID AFTN...AND WIL UPDATE THE HWO TO ADD MENTION
OF SEVERE THREAT. CONFIDENCE WILL INCREASE ONCE TRENDS ON THE CLOUD
COVER BECOME BETTER ESTABLISHED.
PREVIOUS DISCUSSION...
AT 300 AM EDT TUESDAY...AN UPPER TROUGH WIL PERSIST TODAY AND
TONIGHT FORM THE GREAT LAKES TO THE NORTHEAST GULF OF MEXICO. A
SHORTWAVE WILL EXIT THE CAROLINAS THIS MORNING. A SECOND SHORTWAVE
WILL CROSS THE MID MS RIVER VALLEY THIS EVENING...REACHING THE TN
VALLEY LATE TONIGHT. A WEAK SURFACE WAVE AND ASSOCIATED COLD FRONT
WILL CROSS THE GULF STATES TODAY...WHILE MOISTURE INCREASES AHEAD OF
IT. CAPE WILL APPROACH 1000 J/KG BY THIS AFTERNOON...AND SPEED AND
DIRECTIONAL SHEAR WILL EXIST. IF INSTABILITY WERE A BIT GREATER...
DAMAGING WIND GUSTS WOULD BE MORE OF A CONCERN...AS LOW LEVELS ARE
RELATIVELY DRY. CHANCE POPS WILL BE CARRIED TODAY...WITH NEAR LIKELY
POPS IN THE MOUNTAINS. MAXIMUM TEMPERATURES WILL BE SLIGHTLY BELOW
NORMAL.
THE COLD FRONT MOVES THROUGH OUR AREA TONIGHT. THE GFS IS A BIT
FASTER THAN THE NAM TO BRING THE FRONT...AND DRY AIR IN ITS WAKE...
EAST ACROSS OUR AREA. SMALL POPS WILL BE MAINTAINED THROUGH MOST OF
THE NIGHT...LINGERING LASTLY ALONG THE TN BORDER FOR UPSLOPE FLOW.
MINIMUM TEMPERATURES WILL BE AROUND NORMAL.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 205 AM TUESDAY...UPPER HEIGHTS BEGIN TO RISE EARLY WED AND
FLAT RIDGING WILL PREVAIL THROUGH MOST OF THE SHORT TERM. SOME
LINGERING SHOWERS FROM TUE/S FRONTAL SYSTEM COULD AFFECT THE ERN
ZONES AND MORESO THE NC MTNS EARLY WED...BUT THE MODELS HAVE
DIFFERING IDEAS ON THIS SO LITTLE CHANGE WAS MADE TO THE GOING SLT
CHANCES. EXPECT GOOD INSOLATION WED/THU TO ALLOW MAX TEMPS TO REACH
A CAT OR SO ABOVE NORMAL. THE GOOD NEWS IS THE LLVL FLOW WILL REMAIN
W/LY AND AFTERNOON TD/S WILL MIX OUT TO AROUND 60 F...MAKING FOR
WARM BUT RATHER PLEASANTLY DRY CONDITIONS EACH DAY. ISOL TO SCT
SHOWERY ACTIVITY SHOULD DEVELOP ACROSS THE WRN ZONES THU NIGHT AS A
PREFRONTAL TROF BEGINS TO DEEPEN AND MOVES TOWARD THE AREA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 130 AM EDT TUESDAY...GOOD AGREEMENT IS HAD BTW THE LATEST MID
RANGE MODELS WRT THE LARGE UPPER LOW AND THE EVOLUTION OF THE SFC
FRONT APPROACHING THE NC MTNS BY SAT. BEFORE THAT...A SMALL SCALE
UPPER RIDGE BREAKS DOWN OVER THE FCST AREA AND LLVL WINDS RESPOND
OUT OF THE SW ALLOWING A MOISTENING OF THE LLVLS AND AN INCREASE IN
MECHANICAL LIFT ACROSS THE HIGHER TERRAIN. DEWPOINTS WILL RETURN TO
THE MID TO UPPER 60S AND SCT AFTERNOON CONVECTION IS LIKELY ACROSS
THE MAJORITY OF THE AREA INTO THE EVENING. THE PREFRONTAL TROF WILL
PUSH INTO THE AREA EARLY SAT AND -SHRA WILL BE EXPECTED EARLY ON
ACROSS THE NC MTNS...THEN SPREADING EAST AS THE DAY PROGRESSES.
MODEL SOUNDINGS STILL INDICATE LOWER END SBCAPE AND MUCAPE...ESP
ACROSS THE NON/MTNS...WHILE DEEP LAYERED SHEAR REACHES A RESPECTABLE
30 KTS OR SO. THUS...STRONG STORMS ARE PROBABLE WITH A FEW POSSIBLY
REACHING SEVERE CRITERIA SAT AFTERNOON/EVENING. HIGH PRESSURE BUILDS
IN EARLY SUN AND REMAINS THROUGH MON WHICH WILL MAKE FOR A COUPLE
DRY DAYS. MAX TEMPS WILL BE RIGHT AROUND NORMAL FRI AND A FEW
DEGREES COOL SAT WITH ALL THE CLOUD COVER. SUN AND MON WILL
EXPERIENCE AN AIRMASS MIX...SO MAXES SHOULD BE HELD A COUPLE CATS
BELOW NORMAL EACH OF THOSE DAYS.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
AT KCLT...THE DEW POINT DEPRESSION IS NOT SUPPORTIVE OF A FOG
RESTRICTION THIS MORNING. LOW LEVEL CLOUD COVER WILL SPREAD INTO THE
AREA FORM THE SE THIS MORNING AHEAD OF AN APPROACHING COLD FRONT.
LOW VFR CIGS ARE EXPECTED BY AFTERNOON...AND A TEMPO WILL BE CARRIED
FOR AFTERNOON CONVECTION. THE MODELS SUGGEST THAT BREAKS WILL APPEAR
AS THE FRONT MOVES THROUGH TONIGHT...BUT A LOW VFR CIG WILL WILL
GENERALLY PERSIST. SW WINDS WILL INCREASE TO AROUND 10 KNOTS
TODAY...DECREASING TO 5 KNOTS AFTER SUNSET. BETWEEN WINDS AND CLOUD
COVER...NO FOG IS EXPECTED EARLY WEDNESDAY. FRONTAL PASSAGE AND A
WIND SHIFT ARE NOT EXPECTED UNTIL AFTER DAYBREAK WEDNESDAY.
ELSEWHERE...FOG HAS FAILED TO FORM...EVEN WHERE DEW POINT
DEPRESSIONS ARE LOW...AND CONFIDENCE IS DECREASING ON ANY
RESTRICTIONS THIS MORNING. LOW CLOUDS WILL INCREASE FROM THE SW THIS
MORNING...AND SC SITES COULD SEE CONVECTION THIS MORNING BASED ON
RADAR TRENDS IN GA. CONVECTION IS EXPECTED TO PEAK THIS AFTERNOON
WITH BETTER INSTABILITY. AS A COLD FRONT MOVES THROUGH TONIGHT...THE
MODELS SHOW BREAKS IN LOW VFR CLOUD COVER. SW WINDS WILL APPROACH 10
KNOTS TODAY...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY. FRONTAL PASSAGE AND A
WIND SHIFT ARE EXPECTED AFTER DAYBREAK WEDNESDAY.
OUTLOOK...A SLOW MOVING COLD FRONT IS EXPECTED TO CROSS THE SOUTHERN
APPALACHIAN REGION TUESDAY NIGHT...BRINGING A CHC FOR SHRA/TSRA. THE
CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE REGION ON
WEDNESDAY AND REMAIN THROUGH THE WORK WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...ARK/JAT
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...JAT
AREA FORECAST DISCUSSION
NWS ALBANY NY
146 PM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES
REGION...AND THE OHIO VALLEY THIS AFTERNOON WITH AN INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS INTO THIS EVENING. THE
UNSETTLED WEATHER WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE
HIGH PRESSURE BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 100 PM EDT...A WEAK VORT MAX IN THE SW FLOW VIA THE LATEST
RUC40 HAS PRODUCED SOME LIGHT SHOWERS SOUTH OF THE CAPITAL REGION.
IT HAS ALSO PRODUCED PLENTY OF MID AND HIGH CLOUDS ACROSS THE FCST
AREA VIA THE LATEST VISIBLE AND IR TRENDS. THERE WILL LIKELY BE A
BRIEF BREAK BEFORE THE NEXT SHORT-WAVE ASSOCIATED WITH THE TROUGH
OF LOW PRESSURE APPROACHES FROM THE SOUTH AND WEST IN THE LATER
AFTERNOON. EVIDENCE OF THIS IMPULSE ARE THE SHOWERS AND
THUNDERSTORMS MOVING INTO WRN NY AND THE NIAGARA FRONTIER.
WE LOWERED THE CONVECTIVE CHANCES TO SLIGHT CHC VALUES PRIOR TO 6
PM DUE TO THE CANOPY OF CLOUDS AND THE LACK OF INSTABILITY. THE
LATEST SPC MESOANALYSIS SHOWS SBCAPE AND MLCAPE VALUES OF 200-500
J/KG OVER THE FCST AREA. THE MID LEVEL LAPSE RATES REMAIN WEAK
TOO. WE LOWERED MAX TEMPS A FEW MORE DEGREES...BUT KEPT SOME LOWER
80S NORTH AND EAST OF THE CAPITAL REGION WHERE A LITTLE MORE
SUNSHINE WILL OCCUR THROUGH THE CLOUDS.
THE CHANCE OF SHOWERS AND THUNDERSTORMS INCREASE ACROSS THE SRN
DACKS AND CNTRL BTWN 21Z-00Z BASED ON THE LATEST HRRR 3KM COLUMNAR
BASED REF PRODUCT WITH THE SHORT-WAVE.
PREVIOUS DISCUSSION...
EXPECT AN INCREASING CHANCE OF SHOWERS AND SOME THUNDERSTORMS
FROM LATER THIS MORNING INTO TONIGHT WITH MORE SHOWERS AND
THUNDERSTORMS WEDNESDAY INTO WEDNESDAY EVENING AS THE UPPER
TROUGH PASSES THROUGH THE REGION. AT THIS POINT IN TIME IT APPEARS
THE BEST CHANCE FOR THUNDERSTORMS WHICH MAY PRODUCE LOCALLY HEAVY
RAIN WOULD BE LATER THIS AFTERNOON INTO EARLY THIS EVENING WHEN
FIRST H10-H8 THETA E RIDGE AXIS PEAKS ACRS FA WITH SHOWALTER
INDICES AT OR SLIGHTLY BELOW ZERO...MLMUCAPES 300-1000 J/KG AND
PWATS ARND 1.5 INCHES. THE SECOND MOST ACTIVE PERIOD IS EXPECTED
TO BE WEDNESDAY AFTERNOON WITH SLIGHTLY HIGHER PWATS IN THE 1.5 TO
1.67 INCH RANGE...SHOWALTER INDICES SLIGHTLY MORE
NEGATIVE...STRONGER THETA E RIDGE AND MLMUCAPES GREATER BTWN 1500
AND 3000 J/KG.
THE CHANCE OF SEVERE WEATHER REMAINS UNCERTAIN AT THIS TIME AS
PLENTY OF CLOUD COVER DURING THE MID WEEK PERIOD MAY REDUCE
SURFACE HEATING AND CAPES AND H7-H5 LAPSE RATES RATHER
UNIMPRESSIVE UNTIL WEDNESDAY WHEN IT REACHES ABOVE 6 C/KM ACRS
PORTIONS OF THE FA. WEDNESDAY MAY HAVE THE BETTER CHANCE OF MORE
ORGANIZED CONVECTION WITH SLIGHTLY BETTER SHEAR AND 0-3 KM
HELICITY. AT THIS POINT WILL CONTINUE WITH PREVIOUS WORDING IN HWO
MENTIONING A FEW STORMS MAY HAVE DAMAGING WIND GUSTS ON WEDNESDAY.
EXPECT HIGHS TODAY IN THE MID 70S TO MID 80S AND ON WEDNESDAY IN
THE 70S TO LOWER 80S. LOWS TONIGHT ARE EXPECTED TO BE IN THE
UPPER 50S TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WED NIGHT...EXPECT THE UPPER TROUGH AXIS TO SWING THROUGH THE
FA BY LATE EVENING WITH THE THREAT OF SHOWERS DIMINISHING DURING
THE SECOND HALF OF THE NIGHT AND LOWS IN THE MID 50S TO MID 60S.
ON THURSDAY RIDGING BUILDS ACRS THE FA AT THE SURFACE AND ALOFT
AND SLIDES EAST OF THE FA THURSDAY NIGHT PROVIDING DRY AND
SEASONABLE CONDITIONS. EXPECT HIGHS ON THURSDAY IN THE UPPER 70S TO
LOW TO MID 80S WITH LOWS THURSDAY NIGHT IN THE MID 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
HAVE GENERALLY USED A 50/50 BLEND OF 18Z/13 HPC GUIDANCE AND 00Z/14
GMOS FOR THIS PORTION OF THE GRIDDED DATABASE...ALTHOUGH SKEWED
POPS/WEATHER TOWARD THE 00Z/14 ECMWF FOR LATE FRI-SAT EVENING.
FRIDAY...COLD FRONT SHOULD APPROACH FROM THE WEST IN THE AFTERNOON.
HOWEVER...MODELS VARY CONSIDERABLY ON TIMING...WITH THE 00Z/14 GFS
AND GEFS MOST PROGRESSIVE...AND THE 00Z/14 ECMWF SLOWEST. WILL
INDICATE CHC POPS...MAINLY IN THE AFTERNOON HOURS FOR SCATTERED
SHOWERS/TSTMS. EXPECT A WARM AND SOMEWHAT HUMID DAY...WITH MAX TEMPS
REACHING THE LOWER/MID 80S IN VALLEYS...AND 75-80 ACROSS HIGHER
TERRAIN. SHOULD CLOUDS/SHOWERS HOLD OFF UNTIL LATER IN THE
DAY...EVEN WARMER MAX TEMPS COULD OCCUR.
FRI NT-SAT NT...LOW DEGREE OF CONFIDENCE DURING THIS TIME
PERIOD...AS LATEST 00Z/14 ECMWF HAS TRENDED BACK TO A SLOWER
FROPA...WITH WAVE FORMATION ALONG THE BOUNDARY ACROSS THE NORTHERN
MID ATLANTIC STATES TRACKING NE INTO SOUTHERN NEW ENGLAND...IMPLYING
A RATHER WET SATURDAY...WHILE THE 00Z/14 GFS AND GEFS MEAN CONTINUE
WITH A MORE PROGRESSIVE SYSTEM...WITH DRY WEATHER FOR LATE FRI NT
INTO SAT. WILL SIDE CLOSER TO THE ECMWF...AND LINGER CHC POPS ACROSS
MUCH OF THE REGION FOR FRI NT AND EARLY SAT...AND THEN SLOWLY TAPER
POPS FROM NW TO SE SAT AFTERNOON/EVENING. EXPECT MIN TEMPS TO FALL
INTO THE LOWER 60S IN VALLEYS...AND 50S ACROSS HIGHER TERRAIN FOR
FRI NT/SAT AM...WITH MAX TEMPS SAT MAINLY IN THE 70S WITHIN
VALLEYS...AND 65-70 ACROSS HIGHER ELEVATIONS. HOWEVER...EVEN COOLER
MAXES COULD OCCUR IN VALLEY REGIONS SHOULD CLOUDS AND RAIN PERSIST
THROUGH THE AFTERNOON HOURS. SAT NT/SUN AM SHOULD BE COOLER...WITH
MINS FALLING INTO THE 50S IN MOST VALLEYS...AND 45-50 ACROSS HIGHER
ELEVATIONS.
SUN-MON...AT THIS TIME...WILL INDICATE FAIR AND SEASONABLY COOL
CONDITIONS...AS HIGH PRESSURE BUILDS IN FROM THE WEST. EXPECT MAX
TEMPS TO REACH 75-80 IN VALLEY AREAS...AND 70-75 ACROSS HIGHER
ELEVATIONS...WHILE OVERNIGHT MINS FALL INTO THE LOWER/MID 50S IN
MOST VALLEYS...AND 45-50 ACROSS HIGHER ELEVATIONS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
WEAK LOW PRESSURE ACROSS THE OHIO VALLEY REGION WILL APPROACH FROM
THE SOUTHWEST THROUGH TONIGHT. THIS WILL BRING INTERVALS OF
SCATTERED SHOWERS TO THE REGION THROUGH TOMORROW MORNING.
AT THIS TIME...IT APPEARS THAT THE CHANCE FOR THUNDER IS QUITE
LOW...AND THEREFORE WILL KEEP MENTION OUT OF CURRENT SUITE OF
TAFS. ONE AREA OF SHOWERS IS AFFECTING KALB ...KPOU AND KPSF WITH
SOME SPRINKLES. SO...VCSH AT THOSE SITES THROUGH ABOUT 20Z. THERE
LOOKS TO BE A BREAK IN THE SHOWER ACTIVITY INTO THIS EVENING...BUT
RADAR SHOWS MORE SCATTERED SHOWERS TO THE WEST THAT LOOK TO BE
TIMED IN OUR REGION SOME TIME THIS EVENING AND TONIGHT...AS LONG
AS THEY HOLD TOGETHER. MOVEMENT OF THE BAND OF SHOWERS AND
ISOLATED THUNDERSTORMS LOOKS TO BE SLOW MOVING...AND WITH
UNCERTAINTIES IN TIMING BREAKS BETWEEK SHOWERS THROUGH TOMORROW
MORNING...HAVE PUT VCSH IN MOST TIME PERIODS IN ALL TAFS THROUGH
TOMORROW MORNING. SOME MVFR FOG IS POSSIBLE BETWEEN 06Z AND 12Z
DEPENDING ON THE SHOWERS ACTIVITY IR LACK THEREOF. AGAIN...WITH
GUIDANCE SUGGESTING SCATTERED SHOWERS THROUGH TOMRROW
MORNING...AND BASED ON THE CHARACTER OF THE BANS OF SHOWERS WELL
TO THE WEST...PUTTING VCSH TONIGHT THROUGH TOMORROW MORNING. AFTER
12Z...EVEN WITH SHOWRS AROUND...CEILINGS AND VISIBILITIES SHOULD
BE VFR OUTSIDE OF SHOWER ACTIVITY.
NEARLY CALM WINDS WILL OCCASIONALLY BE SOUTHWEST TO SOUTH AT 5-10
KT THROUGH THE PERIOD.
OUTLOOK...
TUE NT-WED...VFR/MVFR. CHC SHRA/TSRA.
WED NT-THU...MAINLY VFR. NO SIG WX EXP AT THIS TIME. CHC MVFR/IFR
WITH BR/FG AT NIGHT.
FRI/SAT...VFR/MVFR. CHC SHRA/TSRA.
SUN...VFR...NO SIG WX.
&&
.FIRE WEATHER...
LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES REGION...AND
THE OHIO VALLEY TODAY WITH AN INCREASING THREAT OF SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON AND EVENING. THE UNSETTLED WEATHER
WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE HIGH PRESSURE
BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
RELATIVE HUMIDITIES ARE EXPECTED TO DROP TO 45 TO 70 PERCENT
TODAY...RECOVER TO 80 TO 100 PERCENT TONIGHT...AND FALL TO 60 TO
80 PERCENT ON WEDNESDAY.
WINDS ARE EXPECTED TO BE SOUTH TO SOUTHWEST AT 5 TO 10 MPH
TODAY...SOUTHWEST TO WEST AROUND 5 MPH TONIGHT...AND SOUTHWEST AT
5 TO 10 MPH ON WEDNESDAY.
&&
.HYDROLOGY...
AT THIS TIME...NO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THE
NEXT 5 DAYS.
MAINLY DRY WEATHER IS EXPECTED THROUGH EARLY THIS MORNING
FOLLOWED BY INCREASING SHOWERS AND SOME THUNDERSTORMS FOR THE MID
WEEK PERIOD. DRY WEATHER IS THEN EXPECTED FOR MUCH OF THE AREA
WEDNESDAY NIGHT THROUGH FRIDAY MORNING WITH MORE UNSETTLED WEATHER
FRIDAY AFTERNOON INTO SATURDAY. TOTAL RAINFALL AMOUNTS THROUGH
WEDNESDAY ARE GENERALLY EXPECTED TO RANGE FROM TWO THIRDS OF AN
INCH TO JUST UNDER AN INCH AND A HALF. HOWEVER...AREAS WHICH
RECEIVE MORE NUMEROUS THUNDERSTORMS CAN EXPECT LOCALIZED HIGHER
AMOUNTS.
DRY WEATHER RETURNS FOR THURSDAY BEFORE A COLD FRONT APPROACHES
FOR FRIDAY INTO THE WEEKEND WITH MORE SHOWERS AND THUNDERSTORMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...NAS/WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...NAS
FIRE WEATHER...11
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
105 PM EDT TUE AUG 14 2012
.SYNOPSIS...LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES
REGION...AND THE OHIO VALLEY THIS AFTERNOON WITH AN INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS INTO THIS EVENING. THE
UNSETTLED WEATHER WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE
HIGH PRESSURE BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 100 PM EDT...A WEAK VORT MAX IN THE SW FLOW VIA THE LATEST
RUC40 HAS PRODUCED SOME LIGHT SHOWERS SOUTH OF THE CAPITAL REGION.
IT HAS ALSO PRODUCED PLENTY OF MID AND HIGH CLOUDS ACROSS THE FCST
AREA VIA THE LATEST VISIBLE AND IR TRENDS. THERE WILL LIKELY BE A
BRIEF BREAK BEFORE THE NEXT SHORT-WAVE ASSOCIATED WITH THE TROUGH
OF LOW PRESSURE APPROACHES FROM THE SOUTH AND WEST IN THE LATER
AFTERNOON. EVIDENCE OF THIS IMPULSE ARE THE SHOWERS AND
THUNDERSTORMS MOVING INTO WRN NY AND THE NIAGARA FRONTIER.
WE LOWERED THE CONVECTIVE CHANCES TO SLIGHT CHC VALUES PRIOR TO 6
PM DUE TO THE CANOPY OF CLOUDS AND THE LACK OF INSTABILITY. THE
LATEST SPC MESOANALYSIS SHOWS SBCAPE AND MLCAPE VALUES OF 200-500
J/KG OVER THE FCST AREA. THE MID LEVEL LAPSE RATES REMAIN WEAK
TOO. WE LOWERED MAX TEMPS A FEW MORE DEGREES...BUT KEPT SOME LOWER
80S NORTH AND EAST OF THE CAPITAL REGION WHERE A LITTLE MORE
SUNSHINE WILL OCCUR THROUGH THE CLOUDS.
THE CHANCE OF SHOWERS AND THUNDERSTORMS INCREASE ACROSS THE SRN
DACKS AND CNTRL BTWN 21Z-00Z BASED ON THE LATEST HRRR 3KM COLUMNAR
BASED REF PRODUCT WITH THE SHORT-WAVE.
PREVIOUS DISCUSSION...
EXPECT AN INCREASING CHANCE OF SHOWERS AND SOME THUNDERSTORMS
FROM LATER THIS MORNING INTO TONIGHT WITH MORE SHOWERS AND
THUNDERSTORMS WEDNESDAY INTO WEDNESDAY EVENING AS THE UPPER
TROUGH PASSES THROUGH THE REGION. AT THIS POINT IN TIME IT APPEARS
THE BEST CHANCE FOR THUNDERSTORMS WHICH MAY PRODUCE LOCALLY HEAVY
RAIN WOULD BE LATER THIS AFTERNOON INTO EARLY THIS EVENING WHEN
FIRST H10-H8 THETA E RIDGE AXIS PEAKS ACRS FA WITH SHOWALTER
INDICES AT OR SLIGHTLY BELOW ZERO...MLMUCAPES 300-1000 J/KG AND
PWATS ARND 1.5 INCHES. THE SECOND MOST ACTIVE PERIOD IS EXPECTED
TO BE WEDNESDAY AFTERNOON WITH SLIGHTLY HIGHER PWATS IN THE 1.5 TO
1.67 INCH RANGE...SHOWALTER INDICES SLIGHTLY MORE
NEGATIVE...STRONGER THETA E RIDGE AND MLMUCAPES GREATER BTWN 1500
AND 3000 J/KG.
THE CHANCE OF SEVERE WEATHER REMAINS UNCERTAIN AT THIS TIME AS
PLENTY OF CLOUD COVER DURING THE MID WEEK PERIOD MAY REDUCE
SURFACE HEATING AND CAPES AND H7-H5 LAPSE RATES RATHER
UNIMPRESSIVE UNTIL WEDNESDAY WHEN IT REACHES ABOVE 6 C/KM ACRS
PORTIONS OF THE FA. WEDNESDAY MAY HAVE THE BETTER CHANCE OF MORE
ORGANIZED CONVECTION WITH SLIGHTLY BETTER SHEAR AND 0-3 KM
HELICITY. AT THIS POINT WILL CONTINUE WITH PREVIOUS WORDING IN HWO
MENTIONING A FEW STORMS MAY HAVE DAMAGING WIND GUSTS ON WEDNESDAY.
EXPECT HIGHS TODAY IN THE MID 70S TO MID 80S AND ON WEDNESDAY IN
THE 70S TO LOWER 80S. LOWS TONIGHT ARE EXPECTED TO BE IN THE
UPPER 50S TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WED NIGHT...EXPECT THE UPPER TROUGH AXIS TO SWING THROUGH THE
FA BY LATE EVENING WITH THE THREAT OF SHOWERS DIMINISHING DURING
THE SECOND HALF OF THE NIGHT AND LOWS IN THE MID 50S TO MID 60S.
ON THURSDAY RIDGING BUILDS ACRS THE FA AT THE SURFACE AND ALOFT
AND SLIDES EAST OF THE FA THURSDAY NIGHT PROVIDING DRY AND
SEASONABLE CONDITIONS. EXPECT HIGHS ON THURSDAY IN THE UPPER 70S TO
LOW TO MID 80S WITH LOWS THURSDAY NIGHT IN THE MID 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HAVE GENERALLY USED A 50/50 BLEND OF 18Z/13 HPC GUIDANCE AND 00Z/14
GMOS FOR THIS PORTION OF THE GRIDDED DATABASE...ALTHOUGH SKEWED
POPS/WEATHER TOWARD THE 00Z/14 ECMWF FOR LATE FRI-SAT EVENING.
FRIDAY...COLD FRONT SHOULD APPROACH FROM THE WEST IN THE AFTERNOON.
HOWEVER...MODELS VARY CONSIDERABLY ON TIMING...WITH THE 00Z/14 GFS
AND GEFS MOST PROGRESSIVE...AND THE 00Z/14 ECMWF SLOWEST. WILL
INDICATE CHC POPS...MAINLY IN THE AFTERNOON HOURS FOR SCATTERED
SHOWERS/TSTMS. EXPECT A WARM AND SOMEWHAT HUMID DAY...WITH MAX TEMPS
REACHING THE LOWER/MID 80S IN VALLEYS...AND 75-80 ACROSS HIGHER
TERRAIN. SHOULD CLOUDS/SHOWERS HOLD OFF UNTIL LATER IN THE
DAY...EVEN WARMER MAX TEMPS COULD OCCUR.
FRI NT-SAT NT...LOW DEGREE OF CONFIDENCE DURING THIS TIME
PERIOD...AS LATEST 00Z/14 ECMWF HAS TRENDED BACK TO A SLOWER
FROPA...WITH WAVE FORMATION ALONG THE BOUNDARY ACROSS THE NORTHERN
MID ATLANTIC STATES TRACKING NE INTO SOUTHERN NEW ENGLAND...IMPLYING
A RATHER WET SATURDAY...WHILE THE 00Z/14 GFS AND GEFS MEAN CONTINUE
WITH A MORE PROGRESSIVE SYSTEM...WITH DRY WEATHER FOR LATE FRI NT
INTO SAT. WILL SIDE CLOSER TO THE ECMWF...AND LINGER CHC POPS ACROSS
MUCH OF THE REGION FOR FRI NT AND EARLY SAT...AND THEN SLOWLY TAPER
POPS FROM NW TO SE SAT AFTERNOON/EVENING. EXPECT MIN TEMPS TO FALL
INTO THE LOWER 60S IN VALLEYS...AND 50S ACROSS HIGHER TERRAIN FOR
FRI NT/SAT AM...WITH MAX TEMPS SAT MAINLY IN THE 70S WITHIN
VALLEYS...AND 65-70 ACROSS HIGHER ELEVATIONS. HOWEVER...EVEN COOLER
MAXES COULD OCCUR IN VALLEY REGIONS SHOULD CLOUDS AND RAIN PERSIST
THROUGH THE AFTERNOON HOURS. SAT NT/SUN AM SHOULD BE COOLER...WITH
MINS FALLING INTO THE 50S IN MOST VALLEYS...AND 45-50 ACROSS HIGHER
ELEVATIONS.
SUN-MON...AT THIS TIME...WILL INDICATE FAIR AND SEASONABLY COOL
CONDITIONS...AS HIGH PRESSURE BUILDS IN FROM THE WEST. EXPECT MAX
TEMPS TO REACH 75-80 IN VALLEY AREAS...AND 70-75 ACROSS HIGHER
ELEVATIONS...WHILE OVERNIGHT MINS FALL INTO THE LOWER/MID 50S IN
MOST VALLEYS...AND 45-50 ACROSS HIGHER ELEVATIONS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
WEAK LOW PRESSURE ACROSS THE OHIO VALLEY REGION WILL APPROACH FROM
THE SOUTHWEST LATER TODAY AND TONIGHT. THIS WILL BRING SOME SHOWERS
TO THE REGION INTO THIS EVENING.
ANY PATCHY GROUND FOG/LOW CLOUDS SHOULD GIVE WAY TO A THICKENING
HIGH AND MID LEVEL VFR CLOUD DECK. ISOLATED TO SCATTERED SHOWERS MAY
APPROACH KPOU AFTER 14Z/TUE...AND THE REMAINING TAF SITES AFTER
17Z/TUE...CONTINUING INTERMITTENTLY THROUGH TONIGHT. AT THIS
TIME...IT APPEARS THAT THE CHANCE FOR THUNDER IS QUITE LOW...AND
THEREFORE WILL KEEP MENTION OUT OF CURRENT SUITE OF TAFS. ISOLATED
TO SCATTERED SHOWERS WILL CONTINUE THROUGH TONIGHT. SOME MVFR VSBYS
WILL BE POSSIBLE LATER TONIGHT FROM THESE SHOWERS AND/OR BR. IN
ADDITION...SOME MVFR/IFR LOW CLOUDS MAY ADVECT NORTHWARD TOWARD
DAYBREAK...POSSIBLY AFFECTING KPOU AND KPSF...WITH A LOWER CHANCE
FOR KALB AND KGFL.
NEARLY CALM WINDS WILL BECOME SOUTHWEST TO SOUTH BY MID MORNING AT
5-10 KT...THEN WILL BECOME LIGHT/VARIABLE AROUND AND AFTER SUNSET.
OUTLOOK...
TUE NT-WED...VFR/MVFR. CHC SHRA/TSRA.
WED NT-THU...MAINLY VFR. NO SIG WX EXP AT THIS TIME. CHC MVFR/IFR
WITH BR/FG AT NIGHT.
FRI/SAT...VFR/MVFR. CHC SHRA/TSRA.
&&
.FIRE WEATHER...
LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES REGION...AND
THE OHIO VALLEY TODAY WITH AN INCREASING THREAT OF SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON AND EVENING. THE UNSETTLED WEATHER
WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE HIGH PRESSURE
BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
RELATIVE HUMIDITIES ARE EXPECTED TO DROP TO 45 TO 70 PERCENT
TODAY...RECOVER TO 80 TO 100 PERCENT TONIGHT...AND FALL TO 60 TO
80 PERCENT ON WEDNESDAY.
WINDS ARE EXPECTED TO BE SOUTH TO SOUTHWEST AT 5 TO 10 MPH
TODAY...SOUTHWEST TO WEST AROUND 5 MPH TONIGHT...AND SOUTHWEST AT
5 TO 10 MPH ON WEDNESDAY.
&&
.HYDROLOGY...
AT THIS TIME...NO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THE
NEXT 5 DAYS.
MAINLY DRY WEATHER IS EXPECTED THROUGH EARLY THIS MORNING
FOLLOWED BY INCREASING SHOWERS AND SOME THUNDERSTORMS FOR THE MID
WEEK PERIOD. DRY WEATHER IS THEN EXPECTED FOR MUCH OF THE AREA
WEDNESDAY NIGHT THROUGH FRIDAY MORNING WITH MORE UNSETTLED WEATHER
FRIDAY AFTERNOON INTO SATURDAY. TOTAL RAINFALL AMOUNTS THROUGH
WEDNESDAY ARE GENERALLY EXPECTED TO RANGE FROM TWO THIRDS OF AN
INCH TO JUST UNDER AN INCH AND A HALF. HOWEVER...AREAS WHICH
RECEIVE MORE NUMEROUS THUNDERSTORMS CAN EXPECT LOCALIZED HIGHER
AMOUNTS.
DRY WEATHER RETURNS FOR THURSDAY BEFORE A COLD FRONT APPROACHES
FOR FRIDAY INTO THE WEEKEND WITH MORE SHOWERS AND THUNDERSTORMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA/11
SHORT TERM...11
LONG TERM...KL
AVIATION...KL/SNYDER
FIRE WEATHER...11
HYDROLOGY...11
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
147 PM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT
STRETCHES FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION...
HAS SPARKED CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND
WEST CENTRAL GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS
HOLD THIS CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS
INTO THE ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER...
CANNOT RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING
HOURS. EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND
SOUTH BUT WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT...
CURRENTLY ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER
THIS AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND
OF CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
.AVIATION...
18Z UPDATE...
VISIBLE SATELLITE LOOP SHOWS A BREAK IN THE CLOUDS OVER ATL WITH
SCATTERED TO BROKEN LOW AND MID CLOUDS OVER THE REMAINDER OF THE TAF
SITES. MORNING MODEL RUNS STILL SHOW ENOUGH MOISTURE AND INSTABILITY
AVAILABLE IN ADVANCE OF THE COLD FRONT TO COMBINE WITH THE DIURNAL
HEATING FOR TSTM DEVELOPMENT. BEST TIME PERIOD FOR CONVECTION WILL
BE 20-24Z. DEPENDING ON THE AMOUNT OF RAINFALL...EXPECT CIGS TO
LOWER TO IFR FROM 09-14Z AT MOST LOCATIONS. DRIER AIR WILL MOVE IN
WITH A NORTHWEST FLOW DURING THE REMAINDER OF WEDNESDAY.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON ALL ELEMENTS.
16
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...16
LONG TERM....20
AVIATION...16
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1248 PM EDT TUE AUG 14 2012
.SYNOPSIS...
AN UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH
THE AREA FROM THE WEST TODAY. THE FRONT WILL BECOME DIFFUSE IN THE
FORECAST AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SCATTERED SHOWERS WERE IN THE FORECAST AREA EARLY THIS AFTERNOON. THE
SHOWERS WERE ASSOCIATED WITH CONVERGENCE AHEAD OF THE COLD FRONT
AND A MID-LEVEL SHORTWAVE TROUGH. COVERAGE HAS BEEN LIMITED BY THE
DRY AIR MASS IN PLACE AHEAD OF THE SHOWERS. THE LATEST RAP SHOWS
THE SHORTWAVE TROUGH WILL BE SHIFTING EAST OF THE FORECAST AREA
LATER THIS AFTERNOON...BUT INCREASED LOW-LEVEL MOISTURE AHEAD OF
THE FRONT AND DIURNAL HEATING SHOULD RESULT IN SCATTERED
THUNDERSTORMS. CLOUDINESS AND THE UPPER-LEVEL LIFT SHIFTING EAST
OF THE FORECAST AREA DURING THE AFTERNOON SHOULD LIMIT
INSTABILITY. THE NAM INDICATES MAINLY WEAK INSTABILITY WITH
AFTERNOON SURFACE LI/S NEAR -5. THE ACTIVITY COULD LINGER INTO THE
EVENING AND POSSIBLY THE OVERNIGHT HOURS BECAUSE OF CONTINUED
CONVERGENCE ASSOCIATED WITH THE WEAK FRONT AND POSSIBLY ANOTHER
MID-LEVEL SHORTWAVE TROUGH. HOWEVER...WE HAVE FORECASTED LOW POPS
BECAUSE OF THE LOSS OF HEATING AND THIS IS ALSO SUPPORTED BY THE
NAM AND GFS MOS GUIDANCE. EXPECT TEMPERATURES NEAR CLIMATOLOGY
WITH HIGHS TODAY NEAR 90 AND LOWS TONIGHT IN THE LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE UPPER TROUGH WILL CONTINUE TO MOVE SLOWLY EAST
ACROSS THE REGION. AT THE SURFACE...MODELS INDICATE THAT THE FRONT
WILL PUSH INTO THE FORECAST AREA AND BECOME DIFFUSE. THE SPC HAS
THE AREA IN A SEE TEXT WITH A MENTION THAT THIS AREA COULD BE
UPGRADED TO A SLIGHT RISK. MODEL TIME SECTIONS SHOW THE AIR MASS
ON WEDNESDAY WILL BECOME MODERATELY UNSTABLE WITH CAPE VALUES
APPROACHING 2000 J/KG...TT AROUND 50 AND LI/S BETWEEN -3 AND -6.
ALSO PRECIPITABLE WATER VALUES WILL BE AROUND 1.8 INCHES. A FEW
OF THE STORMS COULD BECOME STRONG WITH GUSTY WINDS AND LOCALLY
HEAVY RAIN. THE STORMS SHOULD BE MOVING ENOUGH TO PREVENT ANY
SIGNIFICANT FLOODING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
ACROSS THE EASTERN MIDLANDS ALONG AND AHEAD OF THE FRONTAL
BOUNDARY. BY WEDNESDAY NIGHT INTO THURSDAY...THE TROUGH AXIS WILL
MOVE EAST OF THE AREA. WEAK HIGH PRESSURE IS EXPECTED TO BUILD
INTO THE REGION FOR THURSDAY/THU NIGHT. GUIDANCE AND LOCAL NUMBERS
REASONABLY CLOSE THROUGH THE PERIOD AND HAVE STAYED NEAR CONSENSUS
FOR TEMPERATURES AND POPS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
UPPER FLOW BECOMES MORE ZONAL FRIDAY. A LONG-WAVE TROUGH THEN
BEGINS TO DEEPEN WITH ITS AXIS JUST TO THE WEST OF THE APPALACHIAN
MOUNTAINS SATURDAY THROUGH MONDAY. AN INCREASE IN LOW-LEVEL
MOISTURE IS EXPECTED TO YIELD A 20 TO 40 PERCENT CHANCE OF MAINLY
AFTERNOON AND EVENING CONVECTIVE ACTIVITY FRIDAY THROUGH MONDAY.
MAX TEMPERATURES AROUND 90 SHOULD BE THE RULE FRIDAY...BUT COOLING
DOWN SLIGHTLY INTO THE WEEKEND AS THE TROUGH DEVELOPS ACROSS THE
EASTERN HALF OF THE COUNTRY. MORE CLOUDS SATURDAY THROUGH MONDAY
WILL PROBABLY KEEP HIGHS IN THE MIDDLE/UPPER 80S. OVERNIGHT LOWS
IN THE MIDDLE/UPPER 60S TO LOWER 70S FOR MOST OF THE PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
UPPER TROUGH SWINGING ACROSS THE TENNESSEE VALLEY RESULTING IN
CONVECTION OVER GEORGIA WITH VFR CIGS AROUND 6000 FT AHEAD OF THE
CONVECTION OVERSPREADING THE TERMINALS. NOT EXPECTING MUCH IN THE
WAY OF VSBY RESTRICTIONS AT THE TAF SITES WITH THIS CONVECTION.
A COLD FRONT WILL PUSH INTO THE AREA LATER THIS AFTERNOON BUT DEEP
MOISTURE IS LIMITED AS WELL AS INSTABILITY SO CONFIDENCE IS LOW FOR
TIMING CONVECTION AND COVERAGE SHOULD BE WIDELY SCATTERED. EXPECT
CUMULUS ALONG WITH A HIGHER CEILING DUE TO UPSTREAM CONVECTIVE
DEBRIS ADVECTING EASTWARD. WINDS WILL GENERALLY BE CALM THROUGH
SUNRISE THEN INCREASE TO AROUND 10 MPH FROM THE SOUTHWEST...THEN
BECOME LIGHT AFTER SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1151 AM CDT TUE AUG 14 2012
.UPDATE...
UPDATED TO TWEAK TEMPS AND PRECIP FOR THE REMAINDER OF THE DAY.
LARGE AREA OF PRECIP CONTINUES TO AFFECT ALL OF SOUTH CENTRAL AND
WILL EVENTUALLY ENCOMPASS ALL OF SE KS. THIS AREA HAS PRETTY MUCH
PUSHED OUT OF CENTRAL KS. THE PRECIP IS THE RESULT OF AN UPPER WAVE
THAT MOVED OUT OF THE ROCKIES. THE RUC CURRENTLY SHOWS A NICE COLD
POCKET IN THE 305-310K LAYER OVER EASTERN KS WITH FAIRLY STRONG
UPGLIDE INTO THE COLD POCKET OVER THE SOUTHERN HALF OF THE FORECAST
AREA.
THE CLOUDS ASSOCIATED WITH THE PRECIP WILL HOLD DOWN TEMPS
TODAY...ESPECIALLY ACROSS SOUTH CENTRAL AND SE KS. SO WENT AHEAD
AND DECREASED MAXES TODAY OVER THESE AREAS.
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION CONCERN WILL BE LOWER CIGS ASSOCIATED WITH PRECIP
TODAY INTO THE EVENING HOURS.
A FAIRLY LARGE AREA OF PRECIP IS EXPECTED TO CONTINUE AFFECTING
SOUTH CENTRAL AND SE KS TODAY INTO THE EARLY EVENING HOURS. THIS
AREA OF PRECIP IS ASSOCIATED WITH AN UPPER WAVE THAT MOVED OUT OF
THE ROCKIES THIS MORNING WHICH IS NOW PROVIDING SOME ISENTROPIC
UPGLIDE OVER SOUTHERN KS THIS AFTERNOON. WHILE THE MAJORITY OF THE
CIGS ARE IN THE VFR LEVELS...THERE WILL BE A FEW MVFR CIGS IN AREAS
OF PRECIP. THERE WAS EVEN A BRIEF PERIOD OF IFR CIGS JUST NORTH OF
THE PRECIP OVER CENTRAL KS. HOWEVER THE IFR CIGS ARE EXPECTED TO BE
VERY BRIEF. BY THE EARLY EVENING HOURS ONLY SE KS SHOULD STILL SEE
SOME SCT SHOWERS WITH THIS ACTIVITY SOUTH OF THE FORECAST AREA BY
03Z.
LAWSON
&&
.PREV DISCUSSION... /ISSUED 624 AM CDT TUE AUG 14 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
NUMEROUS RAIN SHOWERS FROM ASSOCIATED UPPER LEVEL WAVE WILL SPREAD
EASTWARD ACROSS THE REGION...HOWEVER CLOUD HEIGHTS WILL REMAIN
GENERALLY ABOVE 5000FT SO VFR CONDITIONS ARE EXPECTED TO PREVAIL
FOR ALL SITES. MID-LEVEL CLOUDS WILL BEGIN TO CLEAR OUT FROM WEST
TO EAST THIS AFTERNOON WITH EASTERLY WINDS SWITCHING TO A MORE
SOUTHERLY DIRECTION THIS EVENING.
JAKUB
PREV DISCUSSION... /ISSUED 251 AM CDT TUE AUG 14 2012/
MAIN FORECAST CONCERNS: PRECIPITATION CHANCES OVER THE NEXT FEW
DAYS AND OTHERWISE TEMPERATURES.
TODAY-TONIGHT:
SHORTWAVE TROUGH WITH AN ACCOMPANYING UPPER JET STREAK WILL CONTINUE
MOVING SOUTHEASTWARD ACROSS THE CENTRAL PLAINS TODAY. FORCING WITH
THE WAVE LOOKS DECENT WITH MOISTURE/INSTABILITY LIMITED. THEREFORE
NOT PLANNING TO INCREASE RAIN CHANCES ABOVE 40-60%. RAIN AMOUNTS
SHOULD BE LIGHT (FEW HUNDREDTHS UP TO 0.25 INCH). CLOUD
COVER/PRECIPITATION COULD LIMIT INSOLATION FOR MUCH OF THE DAY AND
SHOULD RESULT IN COOLER THAN SEASONAL HIGH TEMPERATURES AROUND 80 TO
THE MID 80S. PRECIPITATION SHOULD PUSH SOUTHWARD OUT OF THE AREA
LATER THIS AFTERNOON WITH CLEARING SKIES FOR TONIGHT.
WEDNESDAY-THURSDAY:
A STRONG UPPER TROUGH AXIS WILL SWEEP ACROSS THE NORTHERN
PLAINS/UPPER MISSISSIPPI VALLEY WHICH WILL SEND A STRONG COLD FRONT
SOUTHWARD THROUGH THE CENTRAL PLAINS. AHEAD OF THE APPROACHING
FRONT...WEDNESDAY WILL BE A HOT DAY WITH GUSTY SOUTH-SOUTHWESTERLY
WINDS AND PROGGED 850 TEMPERATURES OF 23-28 CELSIUS (NAM-WRF/ECMWF).
GOING HIGHS OF MID 90S TO AROUND 100 LOOK REASONABLE. THE COLD FRONT
WILL MOVE SOUTHWARD ACROSS OUR AREA LATE WEDNESDAY NIGHT THROUGH
THURSDAY. THERE WILL BE A CHANCE OF THUNDERSTORMS AS THE FRONT MOVES
THROUGH. HOWEVER...MAIN UPPER LEVEL SUPPORT SHOULD REMAIN WELL
NORTHEAST OF THE AREA AND MID-LEVEL TEMPERATURES ARE VERY WARM
WEDNESDAY NIGHT BEFORE COOLING SLIGHTLY ON THURSDAY. HIGHEST
THUNDERSTORM CHANCES LOOK TO BE IN THE SOUTHEAST THURSDAY PM/EVE
AS THE FRONTAL TIMING COINCIDES WITH PEAK HEATING/INSTABILITY.
LESSER CHANCES ARE SLATED ELSEWHERE. MUCH COOLER AIR WILL BEGIN
SPREADING SOUTHWARD THURSDAY INTO THURSDAY NIGHT.
FRIDAY-MONDAY:
UPPER PATTERN WILL AMPLIFY FRIDAY INTO THE WEEKEND WITH A LONGWAVE
UPPER TROUGH FROM SOUTHEASTERN CANADA DOWN THROUGH THE EASTERN
CONUS...AND UPPER RIDGING OVER THE WESTERN CONUS. THE ECMWF IS
SLIGHTLY MORE AMPLIFIED THAN THE GFS AND RETAINS THIS INTO
MONDAY...WHEREAS THE GFS BEGINS TO DEAMPLIFY COME EARLY NEXT WEEK.
NORTHWESTERLY FLOW ALOFT WILL PREVAIL OVER OUR FORECAST AREA. COOLER
THAN NORMAL TEMPERATURES FRIDAY AND SATURDAY WILL MODIFY TO CLOSER
TO NORMAL BY MONDAY. A WEAK SHORTWAVE IN THE NORTHWEST FLOW ALOFT
COULD RESULT IN SLIGHT CHANCES FOR SHOWERS/THUNDER SATURDAY.
HOWEVER MOST OF THE PERIOD IS EXPECTED TO REMAIN DRY.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 79 65 97 71 / 60 20 10 30
HUTCHINSON 79 64 98 69 / 70 10 10 30
NEWTON 77 64 97 69 / 70 10 10 30
ELDORADO 77 61 96 70 / 60 20 10 20
WINFIELD-KWLD 80 65 96 73 / 80 20 10 20
RUSSELL 82 64 98 64 / 60 10 10 30
GREAT BEND 80 63 98 66 / 50 10 10 30
SALINA 82 64 99 69 / 80 10 10 30
MCPHERSON 78 64 98 69 / 80 10 10 30
COFFEYVILLE 77 62 94 73 / 70 30 10 20
CHANUTE 77 60 94 71 / 70 30 10 20
IOLA 77 60 95 70 / 70 20 10 20
PARSONS-KPPF 76 61 94 73 / 70 30 10 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
624 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A WEAK RIDGE OF HIGH PRESSURE OVER THE AREA WILL MOVE EAST OF THE
REGION TONIGHT. A TROUGH OF LOW PRESSURE WILL APPROACH LATER
TONIGHT...THEN SLOWLY CROSS THE REGION WEDNESDAY THROUGH
THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
UPDATE...ADJUSTED THE POPS AND SKY TO MATCH UP BETTER W/THE LATEST
CONDITIONS AND RADAR. THE NAM12 AND CANADIAN REGGIE DOING WELL
W/THE SKY AND HRRR ALONG W/THE NAM12 HANDLING THE SHOWERS/TSTMS
WELL. KEPT 40% IN THE AREAS W/THE HEAVIEST CONCENTRATION AND 20%
FOR THE SPOTTY SHOWERS. LATS LAPS SOUNDINGS SUPPORT ENOUGH
INSTABILITY FOR TSTMS TO KEEP GOING INTO THE EARLY EVENING.
ADDED FOG FOR LATE TONIGHT ESPECIALLY ACROSS THE NORTHERN 1/2 OF
THE CWA. NAM/GFS SOUNDINGS SUPPORT THIS AS AIRMASS COOLS
OVERNIGHT. HRLY TEMPERATURES WERE TWEAKED TO MATCH THE LATEST
TRENDS WHICH POINT TO WARMER READINGS INITIALLY.
PREVIOUS DISCUSSION...
ANY SCATTERED SHOWERS OR ISOLATED THUNDERSTORMS THROUGH LATE
AFTERNOON WILL DISSIPATE WITH THE LOSE OF HEATING. CLOUDS WILL
BEGIN TO INCREASE LATER TONIGHT IN ADVANCE OF AN APPROACHING
TROUGH FROM THE WEST. LOWS TONIGHT WILL RANGE FROM THE UPPER 50S
TO LOWER 60S.
EXPECT MOSTLY CLOUDY SKIES ON WEDNESDAY WITH SHOWERS AND
THUNDERSTORMS AS THE TROUGH OF LOW PRESSURE MOVES EAST. HIGHS ON
WEDNESDAY WILL RANGE FROM THE MID TO UPPER 70S ACROSS THE REGION.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
WHATS LEFT OF THE FIRST ROUND OF CNVCTN FROM WED AFTN SHOULD BE
EXITING THE FA VIA NB PROV WED EVE AS THE UPPER S/WV MOVES E.
A SECOND S/WV FROM THE GREAT LAKE WITH ANOTHER ROUND OF SHWRS WILL
APCH WRN PTNS OF THE FA LATE WED NGT/THU MORN WITH PATCHY FOG...THEN
CROSS THE REST OF THE REGION MIDDAY THRU THU AFTN. WE DID INDICATE
A CHC OF THUNDER WITH LIKELY AND GREATER POPS THU AFTN AND ERLY
EVE...BUT WITH LITTLE IF ANY SUNSHINE XPCTD OVR THE REGION...WE DO
NOT XPCT MUCH IN THE WAY OF SB CAPE AND STRONG TSTMS DURG THIS TM.
MAX POPS REACH 80 PERCENT WITH THIS ROUND BASED ON BLENDED MODEL
QPF...BUT FOR NOW...WE CANNOT IDENTIFY ANY 6 HRLY QPF PD
INDICATING MUCH ABV 0.25 INCHES OF RNFL ATTM...SO MENTION OF HVY
RNFL TO GRIDS ATTM.
SHWRS SHOULD END W TO E AS THEY MOVE E AGAIN INTO NB LATE THU NGT
WITH THE LIFTING OUT OF THE UPPER TROF. THERE APPEARS TO BE A
BREAK FRI MORN WITH POSSIBLE SUNSHINE PRIOR TO A THE ARRIVAL OF
A FAIRLY STRONGER COLD FRONT TO NWRN ME BY FRI EVE FROM CNTRL CAN
AS LARGE MID/UPPER VORTEX SETTLES ESE NEAR HUDSON BAY. FOR NOW...
WE BRING POPS UP TO HI CHC RANGE FOR TSTMS MSLY NRN/WRN PTNS OF
FA BY LATE FRI AFTN...GIVEN THAT SUNSHINE FRI MORN WILL INTRODUCE
SOME SB CAPE TO FCST SOUNDINGS FRI AFTN.
AFT A LITTLE ABV AVG LOWS WED NGT...HI TEMPS THU WILL DEFINITELY
BE HELD DOWN TO BLO NORMAL BY CLD CVR AND SHWRS...WITH HI TEMPS
FRI CLOSE TO OR SLIGHTLY ABV NORMAL AFT NEAR NORMAL LOW THU NGT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT PASSES TO THE EAST OF THE AREA AT THE BEGINING OF
THIS PERIOD THEN HIGH PRESSURE WILL BUILD IN FROM THE WEST AND
CREST OVER THE AREA SUNDAY. UPPER TROUGH THEN APPROACHES FROM THE
GREAT LAKES MONDAY. THIS SYSTEM WILL MOVE ACROSS THE REGION
TUESDAY. HAVE USED THE GMOS TO INITIALIZE GRIDS. WILL ADJUST POP
AND SKY COVER GRIDS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: MAINLY VFR THROUGH TONIGHT. THE EXCEPTION WILL BE IN
ANY PATCHY FOG LATER TONIGHT WHICH COULD RESULT IN LOCALIZED
MVFR/IFR VSBYS. CONDITIONS SHOULD BE MAINLY VFR WEDNESDAY BUT
COULD DETERIORATE TO MVFR DURING WEDNESDAY AFTERNOON IN
SHOWERS/TSTMS.
SHORT TERM: MSLY IFR WED NGT AND MVFR THU AND THU EVE ALL TAF
SITES DUE TO SHWRS AND PATCHY FOG...IMPRVG TO VFR LATE THU NGT
INTO FRI MORN. MVFR WILL AGAIN BE POSSIBLE FRI AFTN NRN TAF SITES
WITH ANY TSTM. EXPECT MVFR CONDITIONS LATE FRIDAY NIGHT INTO
SUNDAY.
&&
.MARINE...
NEAR TERM: WINDS/SEAS WILL REMAIN BELOW SCA LEVELS THROUGH WEDNESDAY.
SHORT TERM: NO HDLNS XPCTD WITH RELATIVELY LGT WINDS AND LITTLE
SWELL COMPONENT WITH WV HTS. KEPT CLOSE TO WW3 WV HTS OVR OUTER
MZS...LOWERED TO ARND 1 FT ALG THE IMMEDIATE COAST...INNER HARBORS/
BAYS. PATCHY MARINE FOG MAY ALSO OCCUR LATE WED NGT INTO THU MORN IN
CONJUNCTION WITH RN SHWRS AS SFC DWPTS RISE ABV SSTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DUDA/HEWITT
SHORT TERM...VJN
LONG TERM...MIGNONE
AVIATION...DUDA/HEWITT
MARINE...DUDA/HEWITT/VJN
AREA FORECAST DISCUSSION...CORRECTION
NWS GRAND RAPIDS MI
346 PM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 312 PM EDT TUE AUG 14 2012
AN AREA OF HIGH PRESSURE WILL PASS SOUTH OF MICHIGAN TONIGHT INTO
WEDNESDAY. THIS SHOULD PROVIDE MOSTLY PARTLY CLOUDY SKIES AND LIGHT
WINDS OVERNIGHT. AS THE HIGH MOVES EAST OF THE AREA WEDNESDAY
SOUTHERLY WINDS WILL BRING HIGHS INTO THE LOWER 80S INLAND OF LAKE
MICHIGAN BY MID AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY WITH SHOWERS AND THUNDERSTORMS. BEHIND THE FRONT EXPECT
COOLER WEATHER INTO THE WEEKEND WITH ONLY A SLIGHT CHANCE OF
SHOWERS EACH DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 312 PM EDT TUE AUG 14 2012
THE MAIN ISSUE WITH THIS FORECAST IS THE THREAT FOR STRONG
THUNDERSTORMS ON THURSDAY WITH THE COLD FRONT. THERE IS ALSO A
LESSER ISSUE WITH THE SHOWERS ASSOCIATED WITH THE WEAK FRONT
MOVING THROUGH THE AREA THIS EVENING.
AS FOR THE EVENING SHOWERS... THE RAP MODEL SOUNDING SHOW THE
EQUILIBRIUM LEVEL NEAR 36,000 FT AGL FOR LATE AFTERNOON AND
EVENING WITH CAPES NEAR 1000 J/KG NORTH AND EAST OF GRR. HOWEVER
THOSE SAME SOUNDING SHOW DEW POINT DEPRESSIONS OF OVER 25C BETWEEN
700 AND 400 MB. AS IT TURNS OUT THE SHOWERS ARE ACTUALLY TOPPING
OUT BELOW 20000 FT AGL. THESE SHOWERS ARE ON A WEAK SHORTWAVE AND
THE SURFACE COLD FRONT MOVING ACROSS CENTRAL LOWER MICHIGAN. ALL
OF THIS SHOULD BE EAST OF THE CWA BY SUNSET.
AS FOR THE CONVECTION ON THE COLD FRONT THURSDAY... SEEMS THE
MODELS ARE SIMILAR NOW IN THE TIMING OF THE FRONT... DURING THE
MID TO LATE AFTERNOON. THAT WOULD SUPPORT THE IDEA OF STRONGER
STORMS AS WOULD THE FORECAST OF A STRENGTHENING LOW LEVEL JET HOWEVER
THE CORE OF THE SPEED MAX IS NORTH AND EAST OF GRR THURSDAY
AFTERNOON WHICH MEANS SPEED DIVERGENCE OVER MOST OF THE CWA DURING
THE PRIME THUNDERSTORM DEVELOPMENT TIME. ALSO NOT SO GOOD IS THE
NAM IS SHOWING UPPER CONVERGENCE OVER SURFACE CONVERGENCE AT 18Z
THURSDAY. RATHER NOT CONDUCIVE FOR STRONG STORMS EITHER. THAT IS
BECAUSE GRR IS UNDER THE RIGHT EXIT REGION OF THE UPPER JET. BY
EVENING AS THE CONVECTION REACHES EASTER LOWER MICHIGAN THE
DYNAMICS IMPROVE. BESIDE ALL OF THAT THERE WILL BE CONSIDERABLE
CLOUDS OVER THE CWA WITH THE FRONT WHICH WILL HOLD DOWN THE
SURFACE TEMPS TOO. SO MY SPIN IS WE WILL SEE A LINE OF STRENGTHENING
STORMS OVER OUR EASTERN CWA DURING THE AFTERNOON.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 345 PM EDT TUE AUG 14 2012
MAIN FORECAST CHALLENGE IS RAIN CHANCES. MAIN CHANGE WAS TO FEATURE
AT LEAST SLIGHT CHANCE POPS FOR ALMOST THE ENTIRE PERIOD.
MODELS FEATURE STRONGLY CYCLONIC FLOW ALOFT ACROSS THE GREAT LAKES
DURING THIS PERIOD. THIS IS ASSOCIATED WITH A PERSISTENT UPPER LOW
CENTERED OVER HUDSON BAY. SEVERAL REINFORCING POT VORT MAXES
ROTATING AROUND THE LOW SHOULD HELP TO ANCHOR IT AND FORCE MULTIPLE
EPISODES OF RAIN SHOWERS OVER OUR AREA. THE SPECIFICS ON
PRECIPITATION FREQUENCY...TIMING AND AMOUNTS ALL REMAIN VERY
UNCERTAIN. HOWEVER...THE HIGHLY UNSETTLED OVERALL PATTERN JUSTIFIES
AT LEAST SLIGHT CHANCE POPS THROUGHOUT. TEMPERATURES WILL BE
SIGNIFICANTLY COOLER THAN NORMAL WITH SOME DAYS POSSIBLY STRUGGLING
TO GET INTO THE 60S DEPENDING ON THE TIMING AND INTENSITY OF
PRECIPITATION THAT OCCURS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 102 PM EDT TUE AUG 14 2012
JUST SOME SCATTERED CU THIS AFTERNOON AND LIGHT WINDS EXPECTED.
LATER TONIGHT...WE COULD SEE SOME REDUCED VISBYS DEVELOP
PARTICULARLY ACROSS SOUTH CENTRAL AND SE LOWER MICHIGAN AS SKIES
SHOULD REMAIN MOSTLY CLEAR THERE. LOOKS LIKE 3-5 SM VISBYS POSSIBLE
SO WENT WITH 4SM AS AN AVERAGE. MID LEVEL CLOUDS AOA 10K FT SHOULD
MOVE IN TOWARD MID MORNING AND LIKELY MITIGATE FG DEVELOPMENT
ESPECIALLY ACROSS SW LOWER MICHIGAN. WILL CONTINUE TO MONITOR.
&&
.MARINE...
ISSUED AT 312 PM EDT TUE AUG 14 2012
WINDS WILL BE CONDUCIVE TO HIGHER WAVES THURSDAY AHEAD OF THE
FRONT AND EVEN MORE SO BEHIND THE COLD FRONT THURSDAY NIGHT. WE
WILL LIKELY HAVE TO ISSUE A SMALL CRAFT ADVIOSRY AND BEACH HAZARD
STATEMENTS.
&&
.HYDROLOGY...
ISSUED AT 312 PM EDT TUE AUG 14 2012
RIVERS ARE RUNNING WELL BELOW ADVISORY LEVELS AND RAINFALL
THURSDAY WILL NOT BE ENOUGH TO CHANGE THAT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...TJT
AVIATION...HOVING
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
342 PM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 312 PM EDT TUE AUG 14 2012
AN AREA OF HIGH PRESSURE WILL PASS SOUTH OF MICHIGAN TONIGHT INTO
WEDNESDAY. THIS SHOULD PROVIDE MOSTLY PARTLY CLOUDY SKIES AND HIGH
WINDS OVERNIGHT. AS THE HIGH MOVES EAST OF THE AREA WEDNESDAY
SOUTHERLY WINDS WILL BRING HIGHS INTO THE LOWER 80S INLAND OF LAKE
MICHIGAN BY MID AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY WITH SHOWERS AND THUNDERSTORMS. BEHIND THE FRONT EXPECT
COOLER WEATHER INTO THE WEEKEND WITH ONLY A SLIGHT CHANCE OF
SHOWERS EACH DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 312 PM EDT TUE AUG 14 2012
THE MAIN ISSUE WITH THIS FORECAST IS THE THREAT FOR STRONG
THUNDERSTORMS ON THURSDAY WITH THE COLD FRONT. THERE IS ALSO A
LESSER ISSUE WITH THE SHOWERS ASSOCIATED WITH THE WEAK FRONT
MOVING THROUGH THE AREA THIS EVENING.
AS FOR THE EVENING SHOWERS... THE RAP MODEL SOUNDING SHOW THE
EQUILIBRIUM LEVEL NEAR 36,000 FT AGL FOR LATE AFTERNOON AND
EVENING WITH CAPES NEAR 1000 J/KG NORTH AND EAST OF GRR. HOWEVER
THOSE SAME SOUNDING SHOW DEW POINT DEPRESSIONS OF OVER 25C BETWEEN
700 AND 400 MB. AS IT TURNS OUT THE SHOWERS ARE ACTUALLY TOPPING
OUT BELOW 20000 FT AGL. THESE SHOWERS ARE ON A WEAK SHORTWAVE AND
THE SURFACE COLD FRONT MOVING ACROSS CENTRAL LOWER MICHIGAN. ALL
OF THIS SHOULD BE EAST OF THE CWA BY SUNSET.
AS FOR THE CONVECTION ON THE COLD FRONT THURSDAY... SEEMS THE
MODELS ARE SIMILAR NOW IN THE TIMING OF THE FRONT... DURING THE
MID TO LATE AFTERNOON. THAT WOULD SUPPORT THE IDEA OF STRONGER
STORMS AS WOULD THE FORECAST OF A STRENGTHENING LOW LEVEL JET HOWEVER
THE CORE OF THE SPEED MAX IS NORTH AND EAST OF GRR THURSDAY
AFTERNOON WHICH MEANS SPEED DIVERGENCE OVER MOST OF THE CWA DURING
THE PRIME THUNDERSTORM DEVELOPMENT TIME. ALSO NOT SO GOOD IS THE
NAM IS SHOWING UPPER CONVERGENCE OVER SURFACE CONVERGENCE AT 18Z
THURSDAY. RATHER NOT CONDUCIVE FOR STRONG STORMS EITHER. THAT IS
BECAUSE GRR IS UNDER THE RIGHT EXIT REGION OF THE UPPER JET. BY
EVENING AS THE CONVECTION REACHES EASTER LOWER MICHIGAN THE
DYNAMICS IMPROVE. BESIDE ALL OF THAT THERE WILL BE CONSIDERABLE
CLOUDS OVER THE CWA WITH THE FRONT WHICH WILL HOLD DOWN THE
SURFACE TEMPS TOO. SO MY SPIN IS WE WILL SEE A LINE OF STRENGTHENING
STORMS OVER OUR EASTERN CWA DURING THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
A COLD FRONT WILL PUSH SOUTH OF THE AREA THURSDAY NIGHT...USHERING
IN A COOL FALL LIKE AIR MASS FOR THE WEEKEND. MAIN POINTS OF
CONTENTION IN THE LONG TERM ARE PRECIP CHANCES AND CHANCES FOR
STRONGER STORMS THURSDAY NIGHT...AND UPPER LOW SHOWER POTENTIAL OVER
THE WEEKEND.
COLD FRONT SHOULD BISECT THE FORECAST AREA FROM NORTHEAST TO
SOUTHWEST THURSDAY EVENING WITH SHOWERS AND THUNDERSTORMS ACROSS THE
CWA. BEST CHANCES WILL LIKELY BE ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. PRECIPITATION WILL LIKELY MOVE SOUTH OF THE AREA BY
FRIDAY MORNING. AS FOR THREAT OF STRONG STORMS...FEEL BETTER
INSTABILITY WILL BE JUST SOUTH AND EAST OF THE FORECAST AREA
THURSDAY NIGHT.
ENVISION DIURNALLY DRIVEN SHOWERS OVER THE WEEKEND WITH AN UPPER LOW
OVERHEAD. LOW LEVEL MOISTURE OFF THE GREAT LAKES WILL LIKELY ADD TO
THE INSTABILITY THAT WILL BE IN PLACE DUE TO THE COLD MID LEVELS.
GFS AND ECMWF STILL AT ODDS OVER A SHORTWAVE AND SURFACE TROUGH THAT
THE GFS SWINGS THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY. HAVE
20 POPS IN THE FORECAST AT THIS POINT UNTIL BETTER AGREEMENT OCCURS.
BOTTOM LINE CONTINUES TO BE A FALL LIKE FEEL FOR LATE IN THE WEEK
AND THE WEEKEND...AS HIGHS AROUND 70 FRI/SAT ONLY WARM TO THE LOW TO
MID 70S SUN/MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 102 PM EDT TUE AUG 14 2012
JUST SOME SCATTERED CU THIS AFTERNOON AND LIGHT WINDS EXPECTED.
LATER TONIGHT...WE COULD SEE SOME REDUCED VISBYS DEVELOP
PARTICULARLY ACROSS SOUTH CENTRAL AND SE LOWER MICHIGAN AS SKIES
SHOULD REMAIN MOSTLY CLEAR THERE. LOOKS LIKE 3-5 SM VISBYS POSSIBLE
SO WENT WITH 4SM AS AN AVERAGE. MID LEVEL CLOUDS AOA 10K FT SHOULD
MOVE IN TOWARD MID MORNING AND LIKELY MITIGATE FG DEVELOPMENT
ESPECIALLY ACROSS SW LOWER MICHIGAN. WILL CONTINUE TO MONITOR.
&&
.MARINE...
ISSUED AT 312 PM EDT TUE AUG 14 2012
WINDS WILL BE CONDUCIVE TO HIGHER WAVES THURSDAY AHEAD OF THE
FRONT AND EVEN MORE SO BEHIND THE COLD FRONT THURSDAY NIGHT. WE
WILL LIKELY HAVE TO ISSUE A SMALL CRAFT ADVIOSRY AND BEACH HAZARD STATEMENTS.
&&
.HYDROLOGY...
ISSUED AT 312 PM EDT TUE AUG 14 2012
RIVERS ARE RUNNING WELL BELOW ADVISORY LEVELS AND RAINFALL
THURSDAY WILL NOT BE ENOUGH TO CHANGE THAT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...DUKE
AVIATION...HOVING
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
102 PM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 406 AM EDT TUE AUG 14 2012
AFTER A MORNING OF AREAS OF DENSE FOG AND SCATTERED RAIN
SHOWERS...MUCH OF THE AREA WILL SEE CLEARING SKIES THIS AFTERNOON.
MUCH OF THE REGION WILL SEE DRY CONDITIONS TONIGHT THROUGH
WEDNESDAY NIGHT AS HIGH PRESSURE MOVES THROUGH. THE CHANCE OF RAIN
WILL COME THURSDAY AS A STRONG COLD FRONT PUSHES THROUGH. MUCH
COOLER WEATHER IS EXPECTED BY THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 1058 AM EDT TUE AUG 14 2012
I EXPUNGED THE FOG FROM OUR GRIDS AND UPDATED OUR ZONE FORECAST TO
DROP ANY REFERENCE TO THE FOG. CURIOUS HOW THE LOW CLOUDS ARE
MIXING OUT MORE QUICKLY ALONG INTERSTATE 96 THEN ELSEWHERE... SO I
TRENDED THE CLOUD GRID THAT WAY. THAT IS I HAVE MORE CLOUDS NORTH
AND SOUTH OF INTERSTATE 96 INTO EARLY AFTERNOON TO ALLOW FOR THE
CLOUDS THAT ARE THERE TO MIX OUT.
A WEAK SHORTWAVE... AS SEEN ON THE RAP DATA AND ALSO SEEN ON THE
WATER VAPOR LOOP... MAY TOUCH OFF AN ISOLATED THUNDERSTORM OVER
OUR NE CWA THIS AFTERNOON. THE SOUNDING DO SHOW CAPES TO NEAR 1000
J/KG AND THE TQ INDEX RISES TO NEAR 25C WHICH IS WELL ABOVE THE
15C THRESHOLD FOR THUNDERSTORM. PROBLEM IS THERE IS VERY LITTLE
MOISTURE IN THE SOUNDINGS BETWEEN 10,000 AND 20,000 FT SO ANY CU
TOWERS THAT WOULD DEVELOP WILL HAVE TO STRUGGLE WITH THE DRY AIR
ENTRAINMENT. EVEN SO I PUT 20 POPS THIS AFTERNOON FOR THAT AREA.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
WILL GO WITH A DENSE FOG ADVISORY FOR NW AREAS OF THE CWA. THIS
AREA HAS SEEN THE MID LEVEL CLOUDS PEEL AWAY AND FOG IS DEVELOPING
UNDER THE CLEAR SKIES. OTHERWISE THE FEW LEFTOVER SHOWER IN THE
EASTERN CWA SHOULD BE CLEARING OUT THE OF CWA BY LATE MORNING.
EXPECT A FAIRLY RAPID CLEARING BEHIND THE SHOWERS INTO THE AFTERNOON.
QUIET WEATHER EXPECTED TONIGHT THROUGH WEDNESDAY NIGHT. TEMPS WILL
REBOUND TO 80 TO 85 FOR WEDNESDAY AS WE BEGIN TO SEE RETURN FLOW
AROUND A SURFACE HIGH.
CURRENT TIMING OF THE COLD FRONT ON THURSDAY MAY DIMINISH A SEVERE
THREAT. MODELS SUGGEST IT WILL PASS THROUGH EARLY AFTERNOON WITH
PLENTY OF CLOUDS AND SHOWERS AHEAD OF IT. THIS MAKES THE
OPPORTUNITY TO BECOME UNSTABLE QUESTIONABLE. EVEN SO...WE SHOULD
SEE A GOOD CHANCE OF SHOWERS AND A FEW STORMS...SO EXPANDED THE
LIKELY POPS OVER ALL OF THE CWA.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
A COLD FRONT WILL PUSH SOUTH OF THE AREA THURSDAY NIGHT...USHERING
IN A COOL FALL LIKE AIR MASS FOR THE WEEKEND. MAIN POINTS OF
CONTENTION IN THE LONG TERM ARE PRECIP CHANCES AND CHANCES FOR
STRONGER STORMS THURSDAY NIGHT...AND UPPER LOW SHOWER POTENTIAL OVER
THE WEEKEND.
COLD FRONT SHOULD BISECT THE FORECAST AREA FROM NORTHEAST TO
SOUTHWEST THURSDAY EVENING WITH SHOWERS AND THUNDERSTORMS ACROSS THE
CWA. BEST CHANCES WILL LIKELY BE ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. PRECIPITATION WILL LIKELY MOVE SOUTH OF THE AREA BY
FRIDAY MORNING. AS FOR THREAT OF STRONG STORMS...FEEL BETTER
INSTABILITY WILL BE JUST SOUTH AND EAST OF THE FORECAST AREA
THURSDAY NIGHT.
ENVISION DIURNALLY DRIVEN SHOWERS OVER THE WEEKEND WITH AN UPPER LOW
OVERHEAD. LOW LEVEL MOISTURE OFF THE GREAT LAKES WILL LIKELY ADD TO
THE INSTABILITY THAT WILL BE IN PLACE DUE TO THE COLD MID LEVELS.
GFS AND ECMWF STILL AT ODDS OVER A SHORTWAVE AND SURFACE TROUGH THAT
THE GFS SWINGS THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY. HAVE
20 POPS IN THE FORECAST AT THIS POINT UNTIL BETTER AGREEMENT OCCURS.
BOTTOM LINE CONTINUES TO BE A FALL LIKE FEEL FOR LATE IN THE WEEK
AND THE WEEKEND...AS HIGHS AROUND 70 FRI/SAT ONLY WARM TO THE LOW TO
MID 70S SUN/MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 102 PM EDT TUE AUG 14 2012
JUST SOME SCATTERED CU THIS AFTERNOON AND LIGHT WINDS EXPECTED.
LATER TONIGHT...WE COULD SEE SOME REDUCED VISBYS DEVELOP
PARTICULARLY ACROSS SOUTH CENTRAL AND SE LOWER MICHIGAN AS SKIES
SHOULD REMAIN MOSTLY CLEAR THERE. LOOKS LIKE 3-5 SM VISBYS POSSIBLE
SO WENT WITH 4SM AS AN AVERAGE. MID LEVEL CLOUDS AOA 10K FT SHOULD
MOVE IN TOWARD MID MORNING AND LIKELY MITIGATE FG DEVELOPMENT
ESPECIALLY ACROSS SW LOWER MICHIGAN. WILL CONTINUE TO MONITOR.
&&
.MARINE...
ISSUED AT 406 AM EDT TUE AUG 14 2012
LIGHT WINDS AND LOW WAVES WILL BE THE SEEN THROUGH WEDNESDAY.
HOWEVER SOUTHERN WINDS WILL BE RAMPING UP WEDNESDAY NIGHT AND
THURSDAY...AHEAD AND AS THE FRONT COMES THROUGH. WE MAY APPROACH
SCA CONDITIONS LATE WEDNESDAY NIGHT/EARLY THURSDAY...BUT THERE
WILL BE EVEN STRONG WINDS IN THE CAA BEHIND THE FRONT BY THE END
OF THE WEEK.
&&
.HYDROLOGY...
ISSUED AT 406 AM EDT TUE AUG 14 2012
NEXT DECENT CHANCE OF RAIN WILL COME THURSDAY/THURSDAY NIGHT WITH
A STRONG COLD FRONT. MANY AREAS SHOULD SEE AROUND A HALF INCH OF
RAIN...WITH LOCALIZED HIGHER AMOUNTS. THIS SHOULD NOT CAUSE ANY
WIDESPREAD HYDRO CONCERNS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...HOVING
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
237 PM CDT TUE AUG 14 2012
.DISCUSSION...
88D MOSAIC LOOP THIS AFTERNOON SHOWING SMALL AREA OF ELEVATED
CONVECTION SLOWLY MOVING ACROSS THE NRN CWA. A FEW STATIONS HAVE
HAD HOURLY PCPN AROUND A TENTH OR SO. EXPECT THOUGH ACTIVITY WILL
WEAKEN AS IT PROGRESSES EASTWARD INTO AREA OF HIGHER CINH.
FOR TONIGHT...NAM/GFS/ECM ALL PLACING SMALL AREA OF QPF IN THE
VICINITY OF THE NRN CWA ASSOCIATED WITH WAA FORCING LIFTING NORTH
INTO THE DAKOTAS/UPPER MIDWEST. HOWEVER...12Z RUN OF 4KM WRF IS DRY
AS WELL AS RAP GUIDANCE.
OTHERWISE...LARGE SCALE FLOW CONSISTING OF A DEEP BROAD TROF
ESTABLISHED OVER THE EASTERN CONUS WITH UPSTREAM NORTHWEST FLOW
EXTENDING ALL THE WAY TO THE BRITISH COLUMBIA COASTLINE. PATTERN
THOUGH WILL GRADUALLY ALTER LATER THIS WEEK WHEN DEEP LOW PRESSURE
OVER THE ALASKAN GULF SHIFT EAST AND PUSHES AN AMPLIFYING RIDGE
TOWARD THE ROCKIES.
IN THE MEANTIME...SHORT TERM FEATURE OF INTEREST CONTINUES TO BE
ANTICIPATED COLD FRONT PUSHING DEEP INTO PLAINS ON WEDNESDAY. LEADING
EDGE OF COLD FRONT SHOULD BE PUSHING INTO THE NRN CWA BY AFTERNOON
AND QUICKLY SLIDE SEWD THROUGH THURSDAY MORNING. SVR STORM THREAT AS
THE BNDRY PUSHES THRU QUITE POSSIBLE IF NOT LIKELY WHEN CAP WEAKENS
BY LATE AFTN. INSTABILITY AND SHEAR WILL BE ABUNDANT...MUCAPE 3500
J/KG...LI -7...EFFECTIVE SHEAR 30-40KT...TO PRODUCE STORMS
CONTAINING LARGE HAIL AND DAMAGING WINDS. EXPECT LINGERING PCPN
ACTIVITY THURSDAY MORNING...FOR THE MOST PART SOUTH OF I-80...SHOULD
COME TO A CLOSE BEFORE AFTN. THIS FRONT WILL BRING A NOTICEABLE
CHANCE IN TEMPS...COMPARED TO AS OF LATE...WITH HIGHS THURSDAY THRU
SUNDAY IN THE MID/UPPER 70S.
FOR MONDAY AND TUESDAY...EXPECT A SLIGHT WARMING TREND OVER THE
CNTRL PLAINS AS AFOREMENTIONED UPPER RIDGE SLIDES CLOSER TO THE
REGION. SHOULD BE ABLE TO REACH LOW/MID 80S FOR AFTN HIGHS.
DEE
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED WITH A
WEAK UPPER LEVEL IMPULSE...ALONG AND AND NORTH A WEAK MID LEVEL
FRONTAL BOUNDARY WILL CONTINUE TO MOVE THROUGH NORTHEAST
NEBRASKA...AFFECTING THE KOFK TAF SITE THROUGH ABOUT 20Z.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH
SOUTH SOUTHWESTERLY WINDS AROUND 12 KNOTS. COULD BE SOME SPORADIC
GUSTS UP TO ABOUT 18 KNOTS. GUSTS COULD REDEVELOP BY 15/15Z
TOMORROW AS WELL AHEAD OF THE NEXT COLD FRONT.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1219 PM CDT TUE AUG 14 2012
.AVIATION...18Z TAFS FOR KOFK...KOMA AND KLNK.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED WITH A
WEAK UPPER LEVEL IMPULSE...ALONG AND AND NORTH A WEAK MID LEVEL
FRONTAL BOUNDARY WILL CONTINUE TO MOVE THROUGH NORTHEAST
NEBRASKA...AFFECTING THE KOFK TAF SITE THROUGH ABOUT 20Z.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH
SOUTH SOUTHWESTERLY WINDS AROUND 12 KNOTS. COULD BE SOME SPORADIC
GUSTS UP TO ABOUT 18 KNOTS. GUSTS COULD REDEVELOP BY 15/15Z
TOMORROW AS WELL AHEAD OF THE NEXT COLD FRONT.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 351 AM CDT TUE AUG 14 2012/
DISCUSSION...
FORECAST CONCERNS EARLY ON WILL BE ANY LINGERING PRECIPITATION AND
CLOUDS TODAY...THEN PRECIPITATION CHANCES TONIGHT AND BETTER
CHANCES FOR RAIN WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
THE 00Z H5 PATTERN HAD THE CENTRAL PLAINS UNDER NORTHWEST FLOW ALOFT
WITH A COUPLE OF EMBEDDED SHORTWAVES. AT 04Z...THE SHORTWAVE OVER
MONTANA HAD ALREADY PUSHED INTO THE DAKOTAS...AND THE SHORTWAVE OVER
COLORADO WAS ADVANCING INTO WRN KANSAS. THE 00Z 80KT H3 JET WAS OVER
NEBRASKA AND THERE WAS SOME DECENT UPR LEVEL DIVERGENCE OVER
COLORADO. THE H85 THETA-E AXIS AXIS AT 06Z WAS OVER THE WESTERN
PLAINS WITH H85 WINDS PER THE VWPS FM THE SOUTH AT AROUND 30 TO
35KTS. STEEP MID LEVEL LAPSE RATES OF 7 TO 8.5 DEG C/KM WERE ALSO IN
THIS REGION. BY 08Z...THE LAST WSR-88D RADAR MOSAIC HAD SOME
SHOWERS AND THUNDERSTORMS FROM THE CNTRL DAKOTAS BACK TOWARD WRN
NEBRASKA...A FEW ECHOES IN CENTRAL AND EASTERN NEBRASKA THAT HAD
WEAKENED FROM EARLIER THIS AM...AND A MORE ORGANIZED AREA OF
PRECIPITATION OVER KANSAS. AN EARLIER RUN OF THE HRRR DID NOT
PICK UP ON THE TSRA FOR CENTRAL NEBRASKA AND THE LATEST RUN IS
DOING A BETTER JOB...WITH A CONTINUED WEAKENING TREND AS THE
STORMS MOVE EAST.
THIS MORNING...THE LOW LEVEL JET IS PROGGED TO CONTINUE FROM 30 TO
35KTS FROM THE WCNTRL DAKOTAS INTO CNTRL NEBRASKA...SOUTH INTO
WRN AND CNTRL KANSAS WITH SOME VEERING DURING THE MORNING. THE
TRENDS ON THE IR SATELLITE WEAKENING AND THE NORTHERN WAVE REMAINS
WEAK AS IT MOVES THRU THE PLAINS WITH OTHER WEAK PIECES OF ENERGY
IN THE NORTHWEST FLOW ALOFT. THE SOUTHERN SHORTWAVE TROF IS
STRONGER AND MAINTAINS IT`S STRENGTH ACROSS KANSAS. SHOULD SEE
SOME CONVECTIVE DEBRIS WITH THESE SYSTEMS THIS MORNING. ALTHOUGH
DYNAMICS ARE WEAK...THETA-E ADVECTION CONTINUES DURING THE MORNING
AND EARLY AFTERNOON ALONG WITH MID LEVEL MOISTURE. WILL MENTION
ISOLATED SHOWERS ACROSS PARTS OF THE SOUTH THIS MORNING WITH A FEW
SPRINKLES FARTHER NORTH...AND COULD SEE AND ISOLATED SHOWER IN THE
NORTH THIS AFTERNOON AND EVENING. WITH THE VARIABLE
CLOUDS...TEMPERATURES COULD BE HELD DOWN...BUT FOR NOW HAVE HIGHS
IN THE MID TO UPPER 80S.
A MUCH STRONGER FRONT WILL MOVE INTO THE FORECAST AREA WEDNESDAY
AFTERNOON. THE LOW LEVEL JET STRENGTHENS TONIGHT AND CONTINUES
INTO WED NIGHT. INSTABILITY AND SHEAR INCREASE WITH THE
APPROACHING FRONT ALONG WITH DEEPER MOISTURE RETURN.
FRONTOGENESIS...UVV...AND STEEP LAPSE RATES ALL SUPPORT THE CHC
FOR SCT THUNDERSTORMS. HAVE MAINTAINED HIGH CHC POPS FOR MOST OF
THE AREA TO LIKELY POPS FOR THE NORTHEAST...WITH INCREASING CHANCE
FOR STORMS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...LINGERING
INTO THURSDAY MORNING. HIGHS WEDNESDAY SHOULD TOP OUT IN THE 90S.
SURFACE HIGH PRESSURE WILL BUILD IN LATER THURSDAY AND FRIDAY WITH
COOLER HIGH TEMPERATURES IN THE 70S AND LOWS IN THE 40S AND 50S.
THE FORECAST INTO THE WEEKEND REMAINS COOL WITH HIGHS IN THE 70S
AND LOWER 80S. THERE COULD BE SOME STORMS SATURDAY WITH A WEAK
FRONTAL PASSAGE.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
319 PM MDT TUE AUG 14 2012
.DISCUSSION...
CONVECTION WAS CERTAINLY SLOW TO GET GOING THIS AFTERNOON...THOUGH
ITS NOW HAVING A GROWTH SPURT DESPITE BEING IN RECYCLE MODE. APPEARS
TO BE A BOUNDARY DRAPED ACROSS THE EASTERN PLAINS...ROUGHLY FROM
KLVS TO KTCC. THIS WILL BE AN AREA TO FOCUS ON THRU THE EVENING.
WEDNESDAY SHOULD BE SIMILAR TO TODAY...THOUGH CONVECTIVE COVERAGE
SHOULD BE EVEN LESS AS MOISTURE CONTINUES TO RECYCLE. THUS...WITH
LESS CLOUD COVER AND PRECIPITATION...TEMPERATURES SHOULD BE
WARMER...AND UP TO 10 DEGREES ABOVE NORMAL.
ON THURSDAY...ANOTHER BACK DOOR FRONT WILL MOVE INTO THE NORTHEAST
PLAINS EARLY...COOLING TEMPERATURES 10 TO 15 DEGREES BELOW
WEDNESDAYS NUMBERS. IT WILL CONTINUE TO DIVE SOUTH AND WEST THRU
THE PLAINS DURING THE DAY...THOUGH JUST HOW FAR REMAINS IN QUESTION.
THE GFS HANGS UP THE FRONT ACROSS THE EAST CENTRAL PLAINS...
MEANWHILE...THE NAM CONTINUES TO PLUNGE THE FRONT SOUTH AND WEST THRU
THE CWA. THIS HAS AN IMPACT ON WHERE THE BEST THUNDERSTORM POTENTIAL
WILL BE THURSDAY AFTERNOON AND EVENING. CLIMO WOULD SUGGEST THAT
UPSLOPE FLOW WILL GET THUNDERSTORMS ACROSS THE EAST SLOPES OF THE
CENTRAL MTN CHAIN GOING EARLY IN THE AFTERNOON...THEN STEERING FLOW
SHOULD TAKE THE STORMS INTO THE PLAINS LATER IN THE AFTN/EVE. HAVING
A HARD TIME BELIEVING THE FRONT WILL PUSH THROUGH THE GAPS OF THE
CENTRAL MTN CHAIN DURING THE AFTERNOON HOURS...THUS...WILL HOLD OFF
ON BRINGING IT THRU UNTIL THE EVENING. THEREFORE...KEPT BEST POPS
ALONG/EAST OF THE CENTRAL MTN CHAIN DURING THE DAY THURSDAY.
HOWEVER...THE FRONT WILL PUSH THROUGH AND USHER IN SOME HIGHER
OCTANE MOISTURE INTO THE RIO GRANDE VALLEY AND PERHAPS AS FAR WEST
AS THE CONTINENTAL DIVIDE THURSDAY NIGHT. CERTAINLY DOES NOT LOOK TO
PUSH AS FAR WEST AS EARLY MODEL RUNS SUGGESTED. NONETHELESS...THIS
SHOULD INCREASE CONVECTIVE COVERAGE FOR FRIDAY ACROSS THE WEST...AND
WILL STILL REMAIN ACTIVE ACROSS THE EAST. FRIDAY MAY BE ONE OF THE
BETTER STORM DAYS OF THE SEASON.
AFTER FRIDAY...IT LOOKS LIKE WE WILL BEGIN RECYCLE MODE ONCE
AGAIN...HOWEVER...A SOUTHEASTERLY FETCH OF GULF MOISTURE WILL
CONTINUE ACROSS THE PLAINS. THIS WILL ALLOW STORMS THAT FIRE OVER
THE MOUNTAINS TO MOVE INTO BETTER MOISTURE AS THEY MOVE OVER THE
PLAINS IN NORTHWESTERLY STEERING FLOW. THUS...THE EAST HAS THE BEST
POTENTIAL FOR CONTINUED WETTING RAINS THROUGH THE WEEKEND. FORECAST
CONFIDENCE IS LOW NEXT WEEK WHERE MODELS DIVERGE ON THE PLACEMENT OF
THE UPPER HIGH.
34
&&
.FIRE WEATHER...
CONVECTION FIRING ACROSS THE REGION THIS AFTERNOON WILL BECOME MORE
WIDESPREAD AS THE EVENING PROGRESSES. STEERING FLOW IS TO THE EAST
SOUTHEAST NEAR 15 MPH ACROSS THE NORTH AND AROUND 5 MPH ACROSS THE
SOUTH. PRECIPITABLE WATER VALUES AND SURFACE DEWPOINT VALUES ARE
CERTAINLY HIGH ENOUGH TODAY TO SUPPORT LOCALLY HEAVY RAINFALL AS
WAS THE CASE MONDAY. DECENT PRECIP COVERAGE WILL LEAD TO EXCELLENT
RECOVERIES ACROSS PORTIONS OF THE NORTHERN MTS AND NE PLAINS...WHILE
THE REMAINDER OF THE AREA SEES GOOD RECOVERIES.
WEDNESDAY WILL BE SLIGHLTY DRIER THAN TODAY WITH MIN RH VALUES TO
TREND 5 TO 10 PCT LOWER. A 700-500MB MID LEVEL DRY LAYER ALREADY
EVIDENCED ON WATER VAPOR OVER ARIZONA WILL ATTEMPT TO SHIFT OF
CENTRAL PORTIONS OF THE STATE. STORMS WILL THUS WILL GUSTIER AND
WETTING RAINFALL FOOTPRINTS NOT AS LARGE. HAINES VALUES WILL BE
AROUND 5 FOR MANY CENTRAL AND WESTERN AREAS. NO SIGNIFICANT WINDS
ARE ANTICIPATED OUTSIDE OF CONVECTION.
A BACK DOOR FRONTAL INTRUSION IS THEN SLATED TO ARRIVE OVER THE E
PLAINS THURSDAY...WITH ANOTHER DECENT PUSH OF LOW LEVEL MOISTURE.
THIS WILL ENHANCE COVERAGE AGAIN ESPECIALLY ALONG AND EAST OF THE
CENTRAL MT CHAIN. LOCALLY HEAVY RAINFALL IS POSSIBLE. WINDS BEHIND
THE FRONTAL BOUNDARY WILL BE NEAR BREEZY AS WELL WITH A MODERATELY
STRONG PRESSURE GRADIENT IN ITS WAKE. THIS FRONT WILL PUSH THRU
THE CENTRAL MT CHAIN THURSDAY EVENING WITH GAP WINDS OF 15 TO 25
WITH GUSTS UP TO 35 MPH. THE EVENT MAY BE STRONGER IF CONVECTIVE
COMPLEX FORMS OVER THE PLAINS. MIN RH VALUES WILL TREND MUCH
HIGHER FOR THE EAST BEHIND THIS FRONT...WHILE THE WEST REMAINS
IN THE 20 PCT RANGE. RECOVERIES THURSDAY NIGHT WILL BE EXCELLENT
FOR MOST OF THE EAST AND THE HIGH TERRAIN.
ANOTHER ACTIVE DAY IS ON TAP FOR FRIDAY WITH WEAK STEERING FLOW...
DEEP MOISTURE...AND PLENTY OF INSTABILITY. LOCALLY HEAVY RAINFALL
THREAT WILL REMAIN ELEVATED. THE UPPER HIGH BACKS OFF INTO ARIZONA
SATURDAY AND SUNDAY ALLOWING NW FLOW TO DOMINATE HEAVY RAINFALL
POTENTIAL ALONG AND EAST OF THE CENTRAL MT CHAIN. MAX TEMPS THRU
THIS ENTIRE PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL FOR THE
EASTERN PLAINS AND SLIGHTLY ABOVE NORMAL OUT WEST. MIN TEMPS WILL
BE ABOVE NORMAL ACROSS THE BOARD.
GUYER
&&
.AVIATION...
18Z TAF CYCLE
AN UPPER DISTURBANCE SLIDING SE OVER NORTHERN NM THIS AFTERNOON
WILL FORCE SHRA/TSRA DEVELOPMENT AFT 20Z. STEERING FLOW WILL BE TO
THE SE NEAR 15 KTS. GREATEST CONFIDENCE FOR STORM IMPACTS IN THIS
FLOW WILL BE KLVS...KSAF...KTCC. HEAVY RAIN AND GUSTY WINDS MAY
REDUCE VSBYS/ CIGS DOWN AS LOW AS 030 AND 2SM HOWEVER CONFIDENCE
NOT HIGH ENOUGH AT ANY SPECIFIC LOCALE SO TEMPO WILL HOLD VFR FOR
NOW. LATEST RUC AND HRRR MODELS INDICATE CONVECTION MAY ORGANIZE
OVER THE EAST AS AREA OF STRATIFORM PRECIP AFTER 02Z SO POTENTIAL
EXISTS FOR LONGER DURATION VFR BKN CIGS AND -RA POSSIBLE FOR KTCC
AND KROW. CLOUDS EXPECTED TO BREAK TO SCT MID LEVEL CLOUDS AFTER
MIDNIGHT THEN CLEAR BY SUNRISE ALL AREAS. GUYER/24
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 61 92 61 93 / 20 10 10 20
DULCE........................... 49 87 50 86 / 30 20 20 30
CUBA............................ 54 88 55 87 / 30 20 20 30
GALLUP.......................... 55 88 55 89 / 20 20 20 20
EL MORRO........................ 53 83 53 82 / 20 20 20 30
GRANTS.......................... 53 88 55 88 / 20 20 20 20
QUEMADO......................... 57 88 56 86 / 30 20 20 30
GLENWOOD........................ 62 92 62 91 / 20 20 20 20
CHAMA........................... 44 82 47 81 / 30 30 30 40
LOS ALAMOS...................... 59 85 60 83 / 30 30 20 40
PECOS........................... 57 83 58 79 / 30 30 30 50
CERRO/QUESTA.................... 52 79 53 78 / 30 30 30 50
RED RIVER....................... 47 74 47 70 / 30 40 40 60
ANGEL FIRE...................... 43 77 45 71 / 30 40 30 60
TAOS............................ 51 85 53 83 / 30 30 30 50
MORA............................ 53 79 55 75 / 30 30 30 50
ESPANOLA........................ 58 90 59 89 / 30 20 20 30
SANTA FE........................ 58 87 60 83 / 30 30 20 40
SANTA FE AIRPORT................ 59 90 60 87 / 30 20 20 30
ALBUQUERQUE FOOTHILLS........... 65 92 67 90 / 30 10 20 30
ALBUQUERQUE HEIGHTS............. 68 93 69 91 / 20 10 20 20
ALBUQUERQUE VALLEY.............. 66 95 66 93 / 20 10 20 20
ALBUQUERQUE WEST MESA........... 67 94 67 92 / 20 10 20 20
LOS LUNAS....................... 65 94 66 92 / 20 10 20 20
RIO RANCHO...................... 67 94 67 92 / 20 10 20 20
SOCORRO......................... 67 96 68 95 / 20 10 20 20
SANDIA PARK/CEDAR CREST......... 58 88 62 87 / 30 20 20 40
TIJERAS......................... 61 89 62 89 / 30 20 20 30
MORIARTY/ESTANCIA............... 58 89 59 84 / 30 20 20 40
CLINES CORNERS.................. 58 88 60 80 / 30 20 20 50
GRAN QUIVIRA.................... 62 88 61 86 / 30 20 20 30
CARRIZOZO....................... 63 92 64 90 / 20 20 20 30
RUIDOSO......................... 60 83 60 82 / 30 30 30 40
CAPULIN......................... 57 85 57 74 / 30 20 30 40
RATON........................... 58 91 57 82 / 30 20 30 40
SPRINGER........................ 59 88 59 82 / 30 20 30 40
LAS VEGAS....................... 55 86 57 79 / 30 30 30 50
CLAYTON......................... 62 92 60 79 / 20 20 30 40
ROY............................. 62 89 62 79 / 30 20 30 40
CONCHAS......................... 68 95 69 87 / 30 20 20 40
SANTA ROSA...................... 68 96 67 89 / 30 20 20 50
TUCUMCARI....................... 68 99 68 89 / 20 20 20 40
CLOVIS.......................... 67 96 66 89 / 20 20 20 30
PORTALES........................ 67 97 67 90 / 20 20 20 30
FORT SUMNER..................... 70 96 70 91 / 20 10 20 30
ROSWELL......................... 71 100 71 97 / 20 10 10 20
PICACHO......................... 65 93 66 91 / 20 20 20 30
ELK............................. 62 86 63 86 / 30 20 20 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1158 AM MDT TUE AUG 14 2012
.AVIATION...
18Z TAF CYCLE
AN UPPER DISTURBANCE SLIDING SE OVER NORTHERN NM THIS AFTERNOON WILL
FORCE SHRA/TSRA DEVELOPMENT AFT 20Z. STEERING FLOW WILL BE TO THE SE
NEAR 15 KTS. GREATEST CONFIDENCE FOR STORM IMPACTS IN THIS FLOW WILL
BE KLVS...KSAF...KTCC. HEAVY RAIN AND GUSTY WINDS MAY REDUCE VSBYS/
CIGS DOWN AS LOW AS 030 AND 2SM HOWEVER CONFIDENCE NOT HIGH ENOUGH AT
ANY SPECIFIC LOCALE SO TEMPO WILL HOLD VFR FOR NOW. LATEST RUC AND
HRRR MODELS INDICATE CONVECTION MAY ORGANIZE OVER THE EAST AS AREA
OF STRATIFORM PRECIP AFTER 02Z SO POTENTIAL EXISTS FOR LONGER DURATION
VFR BKN CIGS AND -RA POSSIBLE FOR KTCC AND KROW. CLOUDS EXPECTED TO
BREAK TO SCT MID LEVEL CLOUDS AFTER MIDNIGHT THEN CLEAR BY SUNRISE
ALL AREAS. GUYER/24
&&
.PREV DISCUSSION...332 AM MDT TUE AUG 14 2012...
A MOISTURE RECYCLE MODE DAY TODAY AS SIGNIFICANT LOW LVL MOISTURE
INFLUX HAS PRETTY MUCH ENDED...ESPECIALLY NW TWO THIRDS OR SO OF
NM. WITH THE PREVIOUS BACK DOOR FRONT BRING IN SOME ADDTL LOW LVL
MOISTURE AND MID AND HIGH LVL MOISTURE STILL SNEAKING TO SOME
DEGREE INTO THE S SIDE OF THE EVER PRESENT UPPER HIGH STRETCHING
FROM W TX INTO S AZ. THUS IT HAS BECOME ONE OF THE SO CALLED
DIRTIER HIGHS THIS FCSTR HAS SEEN IN MANY A MOON. SO AT LEAST
ENOUGH MOISTURE REMAINS TO STILL REACT WITH DAYTIME HEATING AND
THE OCCASIONAL WEAK DISTURBANCE ROTATING AROUND THE HIGH PRESSURE
CENTER TO TRIGGER A SCATTERING OF SHOWERS AND STORMS. COVERAGE
TODAY SHOULD BE NEAR TO SLIGHTLY BELOW MONDAY/S LEVELS AND
RAINFALL AMTS FROM THE STRONGEST STORMS LIKELY TO BE A BIT
LESS...BUT A FEW HEAVY RAINERS ARE STILL QUITE LIKELY. GFS AND NAM
MODELS STILL SHOW A MINOR/WEAK WIND SHIFT INTO THE NE A LITTLE
LATER TODAY...BUT NOT MUCH IMPACT ON WX EXPECTED THERE OTHER THAN
THE WIND SHIFT. DOWNWARD TREND OF STORM COVERAGE SHOULD CONTINUE
ON WED. THE HIGH TEMPERATURES TODAY AND WED WILL BE MOSTLY ABOVE
NORMAL.
A SHORT WAVE TROUGH PASSING N AND NE OF NM THU WILL EJECT A BACK
DOOR FRONT INTO THE NE. THIS FRONT WILL DRIVE S AND W LATER THU
AND THU NIGHT BRINGING ANOTHER MODERATE E CANYON WIND EVENT INTO
THE RIO GRANDE VALLEY. THIS FRESH INFLUX OF MOISTURE WILL ENHANCE
STORM COVERAGE FOR THU AND FRI OVER THE FORECAST AREA. SHOULD
BRING A ROUGHLY 5 TO NEARLY 15 DEGREE TEMPERATURE DROP IN THE NE
THU AND SE ON FRI. LESSER DROPS FARTHER WEST ON FRI. MOISTURE
RECYCLING MODE RETURNS FOR THE UPCOMING WEEKEND AND EARLY NEXT
WEEK. OVERALL COVERAGE DURING THIS TIME SHOULD DIMINISH. MEANWHILE
TEMPERATURES IN THE E WILL RETURN TO ABOVE NORMAL READINGS.
43
.FIRE WEATHER...
CRITICAL FIRE WEATHER...NOT EXPECTED THROUGH NEXT WEEKEND AND INTO
MONDAY OF THE FOLLOWING WEEK.
MODELS...IN ROUGH AGREEMENT THROUGH THE WEEKEND AND INTO THE
FOLLOWING WORK WEEK IN A WEAKLY FORCED PATTERN. RIDGE CENTROID OVER
THE SOUTHWESTERN U.S. WILL AMPLIFY PATTERN WITH RIDGE EXTENSION WELL
INTO THE PACIFIC NORTHWEST HEADING INTO THE WEEKEND. AS RIDGE
CENTROID SHIFTS WESTWARD TO ARIZONA AND SOUTHERN
CALIFORNIA...AMPLIFIED PATTERN WILL START BRINGING QUICK HITTER
DISTURBANCES OUT OF THE PACIFIC NORTHWEST SOUTHEAST TO TEXAS AND
OKLAHOMA...AND SOME OF THESE WILL CLIP THE NORTHEAST CORNER OF NEW
MEXICO ON THE WAY. RIDGE WILL EXPAND BACK TO THE EAST LATE MONDAY TO
SHIFT THE DISTURBANCE TRACK AWAY FROM NEW MEXICO...AND THEN THE
CENTROID REDEVELOPS OVER NEW MEXICO BY MIDWEEK NEXT WEEK.
FOR TODAY...BROAD SCATTERED SHOWER AND THUNDERSTORM COVERAGE ON TAP
BY THIS AFTERNOON...WITH BEST CHANCES FOR WETTING RAIN OVER THE
NORTHERN MOUNTAINS CLOSE TO THE COLORADO LINE. SURFACE WINDS WILL
SHIFT TO THE NORTHWEST OVER THE WESTERN END OF THE STATE...WITH WIND
DIRECTIONS REMAINING MORE WESTERLY CENTRAL AND SOUTHWESTERLY OVER
THE EASTERN PLAINS. WITH TEMPERATURES REMAINING 3 TO 8 DEGREES ABOVE
NORMAL...MINIMUM HUMIDITIES WILL RUN MAINLY IN THE UPPER TEENS AND
LOW 20S PCT WITH GOOD TO EXCELLENT HUMIDITY RECOVERIES OVERNIGHT.
VENTILATION GENERALLY IN GOOD SHAPE...WITH SOME DEGRADATION OVER
THE NORTHERN TIER AND NORTHEAST HIGHLANDS AND PLAINS IN WEAKER
TRANSPORT WINDS.
FOR WEDNESDAY...RIDGE CORE CENTERED OVER THE DRAGOON MOUNTAINS OF
SOUTHEAST ARIZONA....AND WILL HELP REDUCE THUNDERSTORM COVERAGE AND
INTENSITY FOR A GENERAL DOWN TICK IN CONVECTIVE ACTIVITY. HIGH
COUNTRY WEST AND CENTRAL FAVORED...WITH SOME ENHANCEMENT OVER THE
NORTHEAST HIGHLANDS AND NORTHEAST PLAINS IN VICINITY OF WEAK TROUGH
AXIS. WIND SPEEDS REMAINING LIGHT WITH STEADY TEMPERATURE PROFILES
AND WEAK DRYING TREND. MINIMUM HUMIDITIES REMAINING PRETTY MUCH IN
THE UPPER TEENS AND LOW 20S PCT...WITH MORE TEENS THAN 20S WEDNESDAY
OVER THOSE OBSERVED ON TUESDAY. VENTILATION GENERALLY GOOD...WITH
MARGINAL CONDITIONS CONTINUING OVER THE NORTHEAST PLAINS.
FOR THURSDAY...COLD FRONT OFF THE FRONT RANGE OF THE ROCKIES AND
CENTRAL PLAINS WILL PUSH INTO THE NORTHEAST PLAINS THURSDAY DAYTIME
AND ROLL SOUTHWARD AND BULGE WESTWARD AGAINST THE CENTRAL MOUNTAIN
CHAIN BY THURSDAY NIGHT. WINDS PICKING UP STRONG EASTERLY COMPONENT
AS THE FRONT MOVES IN...WITH SOME UPSLOPE FLOW SUPPORTING AN
INCREASE IN THUNDERSTORM COVERAGE AND INTENSITY. STORMS MOST LIKELY
OVER THE SANGRE DE CRISTO SUMMITS AND EASTERN SLOPES...WITH HIGH
COUNTRY STORM STARTS EXPANDING STEADILY TO VALLEYS AND PLAINS
THROUGH THE DAY. DOUBLE DIGIT TEMPERATURE DROPS OVER THE EAST...AND
A FEW DEGREES DOWN OVER THE CENTRAL AND WEST WILL BRING MAXIMUM
TEMPERATURES TO WITHIN A FEW DEGREES OF NORMAL...WITH 5 TO 10 DEGREE
DEPARTURES BELOW NORMAL OVER THE NORTHEAST. MINIMUM HUMIDITIES
BOOSTING INTO THE UPPER 20S AND 30S PCT...WITH THE LAST OF THE TEENS
PCT OVER THE NORTHWEST PLATEAU. NO VENTILATION ISSUES EXPECTED.
OVERNIGHT...GOOD TO EXCELLENT HUMIDITY RECOVERIES...AND EASTERLY GAP
WINDS DEVELOPING THROUGH THE CENTRAL MOUNTAIN CHAIN AND BLOWING OUT
OVER THE RIO GRANDE VALLEY INTO EARLY FRIDAY MORNING.
OUTLOOK...FRIDAY THROUGH THE WEEKEND...SLOW BUT STEADY TEMPERATURE
REBOUND AND WEAK DRYING TREND AS RIDGE CENTROID SHIFTS TO WESTERN
ARIZONA...AND NORTHWEST FLOW IS ABLE TO DENT THE EASTERN EDGE OF THE
RIDGE AND BRING SOME QUICK HITTER DISTURBANCES ACROSS THE NORTHEAST
CORNER OF NEW MEXICO THROUGH SATURDAY. RIDGE EXPANDING BACK TO THE
EAST ON SUNDAY TO SHIFT NORTHWEST FLOW OUT OF NEW MEXICO INTO THE
HEART OF TEXAS...AND RETURNING A RECYCLING CONVECTIVE PATTERN TO THE
STATE. THIS WILL SHOW UP AS A GENERAL TREND TOWARD REDUCED
THUNDERSTORM COVERAGE AND INTENSITY. WINDS GENERALLY SOUTHEASTERLY
VEERING TO SOUTHERLY THROUGH THE WEEKEND. SOME MARGINAL VENTILATION
CENTRAL AND SOUTHWEST...BUT GOOD CONDITIONS ELSEWHERE THROUGH THE
WEEKEND.
SHY
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
220 PM EDT TUE AUG 14 2012
.SYNOPSIS...
TODAY THROUGH WEDNESDAY, LOW PRESSURE WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS WESTERN NEW YORK AND THEN INTO SOUTHERN
QUEBEC. THIS SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS TO THE
AREA PRIMARILY THIS AFTERNOON AND EVENING. UNSETTLED WEATHER WILL
CONTINUE THROUGH WEDNESDAY BEFORE HIGH PRESSURE BRINGS DRY AND
SEASONAL CONDITIONS ON THURSDAY. ANOTHER COLD FRONT WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1230 PM UPDATE...CURRENT FORECAST IN GOOD SHAPE. CONVECTION WILL
INCREASE ACROSS THE WESTERN FA DURING THE NEXT COUPLE OF HOURS AND
TRACK EAST THROUGH CENTRAL NY/NE PA THROUGH THIS EVENING. SPC SITE
SHOWS ML CAPE VALUES UP TO 500 J/KG ACROSS THE WESTERN AND PARTS
OF THE CENTRAL SOUTHERN TIER WHERE SKIES ARE PARTLY SUNNY. AS
DAYTIME HEATING CONTINUES ML CAPES BTW 800-1200 J/KG MAY BE
REALIZED WHICH COULD LEAD TO A FEW SVR STORMS LATER THIS AFTERNOON
INTO THE EVENING HOURS.
10 AM UPDATE...AREA OF SHOWERS AND ISOLATED THUNDERSTORMS NOW
DEPARTING THE WESTERN CATSKILLS AND POCONOS AS MID LEVEL SHORT
WAVE AND WEAK ISENTROPIC LIFT SHIFTS EAST. SATELLITE SHOWS
CLEARING SKIES ACROSS WESTERN NY AND INTO THE CENTRAL SOUTHERN
TIER. THIS AREA OF CLEARING IS EXPECTED TO MAKE PROGRESS ACROSS
THE FINGER LAKES REGION INTO THE LAKE PLAIN AND PARTS OF THE
SOUTHERN TIER. THIS WILL DESTABILIZE THE ATMOSPHERE PRIOR TO THE
NEXT MORE WIDESPREAD ROUND OF SHOWERS AND THUNDERSTORMS AS SFC LOW
TRACKS INTO WESTERN NEW YORK. CONVECTION WILL INCREASE LATER THIS
AFTERNOON INTO THE EVENING WITH STILL THE THREAT THAT A FEW MAY
BECOME SEVERE. JUST MINOR ADJUSTMENTS TO SHORT TERM POPS/CLOUDS/TEMPS.
.PREVIOUS DISC...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST
OF THE AREA BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY
SEVERE POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE
OF THESE SHOWERS THROUGH MID- AFTERNOON... BEFORE ANOTHER WAVE
ROTATING AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF
CONVECTION LATER THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME
CLEARING IS OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT
THIS POINT EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR
AREA THIS AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE
RANGE OF POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR
1000 J/KG. NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE
THIS AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT
WITH DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH
TO PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO
THIS EVENING. HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT
APPEARS TO BE LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN
ASSOCIATION WITH A WEAK... POORLY ORGANIZED SURFACE LOW... AND
MID-TO-UPPER LEVEL HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL
OF THE ABOVE REASONING EXPECT A FEW STRONG TO MARGINALLY SEVERE
STORMS TO DEVELOP LATER THIS AFTERNOON WITH ISOLATED SEVERE
REPORTS LIKELY BUT NOT A WIDESPREAD EVENT. SPC HAS THE SOUTHERN
HALF OF OUR AREA IN A SLIGHT RISK OF SEVERE WEATHER TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
2 PM UPDATE...
WE WILL START OFF THE EXTENDED PERIOD UNSETTLED WITH A TREND
TOWARD DRIER BUT COOLER WEATHER OVER THE WEEKEND. BEST SHOT AT
PRECIPITATION IN THIS PERIOD WILL COME FRIDAY NIGHT WITH A FRONT
MOVING THROUGH. THE 12Z GFS AND CANADIAN ARE FASTER WITH THE
FRONT...DRYING US OUT BY 12Z SATURDAY. THE 0Z EURO IS MUCH
SLOWER AND ACTUALLY SLOWER THAN THE PREVIOUS RUNS OF THIS MODEL.
FOR NOW WILL LEAVE IN CHANCE POPS OVER THE FAR SOUTHEAST THROUGH
EARLY SATURDAY MORNING. WE MAY BE ABLE TO YANK THESE THOUGH IF THE
12Z EURO COMES IN FASTER...MORE IN LINE WITH THE OTHER LONG RANGE GUIDANCE.
WE SHOULD SEE A PERIOD OF DRY WEATHER FOR THE REST OF SATURDAY
INTO MOST OF SUNDAY BEFORE WE BEGIN TO SEE THE INFLUENCE OF A
DIGGING H5 TROF OVER THE OHIO VALLEY. BOTH THE GFS AND CANADIAN
ARE A BIT MORE AGGRESSIVE IN SENDING MOISTURE ARE WAY BY LATE
SUNDAY...WHICH MAY BE ENOUGH WITH FALLING H5 HEIGHTS FOR SOME
ISOLATED SHOWERS ESPECIALLY WEST OF I-81. STILL FEEL THE BETTER THREAT
FOR CONVECTIVE SHOWERS WITH THE UPPER LEVEL TROF WILL INCREASE
THROUGH MONDAY...BEFORE REACHING A PEAK TUESDAY WITH THE TROF AXIS
MOVING THROUGH. THE BIGGER STORY THIS WEEKEND WILL LIKELY BE THE
TEMPERATURES AS 850 TEMPS REMAIN IN THE SINGLE DIGITS...WHICH WILL
KEEP HIGHS IN THE LOWER TO MIDDLE 70S. PERHAPS A SIGN FALL IS NOT
TOO FAR AROUND THE CORNER.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
200 PM UPDATE...A FEW SHOWERS ARE POSSIBLE WITH MAINLY VFR
CONDITIONS AND A GRADUAL LOWERING OF THE MID DECK TO AROUND 6KFT
THROUGH 21Z. AFTER THAT...AN AREA OF SHOWERS AND THUNDERSTORMS NOW
DEVELOPING ACROSS WESTERN NY WILL MOVE ACROSS THE TERMINALS
ROUGHLY BETWEEN 21Z AND 02Z. BEST WINDOW FOR STORMS WITH MVFR
VSBYS AT THE NY TERMINALS WILL BE BETWEEN 21Z AND 0Z...AND BETWEEN
00Z AND 02Z AT KAVP. AFTER THE STORMS CLEAR VFR THROUGH THE FIRST
HALF OF THE OVERNIGHT.
TOWARD DAYBREAK MVFR CIGS AND VSBYS ARE POSSIBLE AT THE SOUTHERN
NY TERMINALS AND KAVP. IT IS POSSIBLE WE MAY SEE IFR CIGS AT THE
ELEVATED SITES BUT TOO LOW OF CONFIDENCE TO INCLUDE AT THE MOMENT.
AFTER A BRIEF BREAK...MVFR CIGS ARE POSSIBLE AGAIN ESPECIALLY
KITH/KBGM/KRME WITH THE PASSAGE OF A FRONT BY MID WEDNESDAY MORNING.
WINDS 5 TO 10 KTS OUT OF THE SOUTH THROUGH LATE AFTERNOON. NEAR
CALM OR LIGHT/VARIABLE WINDS TONIGHT. WINDS VEER INTO THE
NORTHWEST BY MID WEDNESDAY MORNING AROUND 5 KTS.
OUTLOOK...
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH
MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT/SUN...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE/RRM
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...HEDEN
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1232 PM EDT TUE AUG 14 2012
.SYNOPSIS...
TODAY THROUGH WEDNESDAY, LOW PRESSURE WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS WESTERN NEW YORK AND THEN INTO SOUTHERN
QUEBEC. THIS SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS TO THE
AREA PRIMARILY THIS AFTERNOON AND EVENING. UNSETTLED WEATHER WILL
CONTINUE THROUGH WEDNESDAY BEFORE HIGH PRESSURE BRINGS DRY AND
SEASONAL CONDITIONS ON THURSDAY. ANOTHER COLD FRONT WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1230 PM UPDATE...CURRENT FORECAST IN GOOD SHAPE. CONVECTION WILL
INCREASE ACROSS THE WESTERN FA DURING THE NEXT COUPLE OF HOURS AND
TRACK EAST THROUGH CENTRAL NY/NE PA THROUGH THIS EVENING. SPC SITE
SHOWS ML CAPE VALUES UP TO 500 J/KG ACROSS THE WESTERN AND PARTS
OF THE CENTRAL SOUTHERN TIER WHERE SKIES ARE PARTLY SUNNY. AS
DAYTIME HEATING CONTINUES ML CAPES BTW 800-1200 J/KG MAY BE
REALIZED WHICH COULD LEAD TO A FEW SVR STORMS LATER THIS AFTERNOON
INTO THE EVENING HOURS.
10 AM UPDATE...AREA OF SHOWERS AND ISOLATED THUNDERSTORMS NOW
DEPARTING THE WESTERN CATSKILLS AND POCONOS AS MID LEVEL SHORT
WAVE AND WEAK ISENTROPIC LIFT SHIFTS EAST. SATELLITE SHOWS
CLEARING SKIES ACROSS WESTERN NY AND INTO THE CENTRAL SOUTHERN
TIER. THIS AREA OF CLEARING IS EXPECTED TO MAKE PROGRESS ACROSS
THE FINGER LAKES REGION INTO THE LAKE PLAIN AND PARTS OF THE
SOUTHERN TIER. THIS WILL DESTABILIZE THE ATMOSPHERE PRIOR TO THE
NEXT MORE WIDESPREAD ROUND OF SHOWERS AND THUNDERSTORMS AS SFC LOW
TRACKS INTO WESTERN NEW YORK. CONVECTION WILL INCREASE LATER THIS
AFTERNOON INTO THE EVENING WITH STILL THE THREAT THAT A FEW MAY
BECOME SEVERE. JUST MINOR ADJUSTMENTS TO SHORT TERM POPS/CLOUDS/TEMPS.
.PREVIOUS DISC...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST
OF THE AREA BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY
SEVERE POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE
OF THESE SHOWERS THROUGH MID- AFTERNOON... BEFORE ANOTHER WAVE
ROTATING AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF
CONVECTION LATER THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME
CLEARING IS OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT
THIS POINT EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR
AREA THIS AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE
RANGE OF POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR
1000 J/KG. NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE
THIS AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT
WITH DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH
TO PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO
THIS EVENING. HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT
APPEARS TO BE LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN
ASSOCIATION WITH A WEAK... POORLY ORGANIZED SURFACE LOW... AND
MID-TO-UPPER LEVEL HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL
OF THE ABOVE REASONING EXPECT A FEW STRONG TO MARGINALLY SEVERE
STORMS TO DEVELOP LATER THIS AFTERNOON WITH ISOLATED SEVERE
REPORTS LIKELY BUT NOT A WIDESPREAD EVENT. SPC HAS THE SOUTHERN
HALF OF OUR AREA IN A SLIGHT RISK OF SEVERE WEATHER TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE/RRM
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
541 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER OVER OUR REGION WEDNESDAY AND
THURSDAY BEFORE THE NEXT COLD FRONT REACHES OUR AREA FROM THE
NORTHWEST LATE FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 530 PM...RECENT RADAR IMAGES INDICATE THAT COVERAGE OF TSRA
HAS BEEN INCREASING ACROSS THE FOOTHILLS OF THE CAROLINAS AND
NORTHEAST GA. LATEST CAPE ANALYSIS INDICATES THAT VALUES RANGE FROM
1500 TO 2000 J/KG ACROSS THE FOOTHILLS AND PIEDMONT...WITH DCAPE
VALUES RANGING FROM 1000 TO 1300 J/KG EAST OF THE MTNS. IN
ADDITION...EFFECTIVE SHEAR RANGES FROM 20 TO 30 KTS. GIVEN THE
ENVIRONMENT...FOOTHILL STORMS SHOULD ORGANIZE IN CLUSTERS...FORM
COLD POOLS...AND TRACK EAST. THE PRIMARY THREAT WILL REMAIN DAMAGING
WINDS...A FEW STRONGER STORMS MAY PRODUCE LARGE HAIL. I WILL UPDATE
THE FORECAST FOR POP PLACEMENT AND TIMING.
AS OF 145 PM...POPS HAD TO BE ADJUSTED AGAIN TO CHASE TRENDS. A
HEALTHY CU FIELD CAN BE SEEN ON VISIBLE...BUT JUST DOESN/T SEEM TO
BE ABLE TO BREAK THRU. THE 13Z HRRR IS THE CLOSEST TO REALITY...AND
IT REALLY ONLY HAS A FEW CELLS DEVELOPING ACRS THE NC MTNS THRU THE
AFTN HOURS. SO POPS WERE PUSHED BACK TO LATE AFTN/EVE...WHICH ARE
PROBABLY STILL OVERDONE. TEMPS ARE STILL LAGGING. ONE THING TO NOTE
IS THAT THE MODIFIED FFC SOUNDING THIS MORNING SHOWED THAT A FCST
MAX TEMP OF 87-89 STILL RESULTED IN SOME CIN. STILL EXPECT A VORT
MAX TO ENTER THE AREA LATER THIS AFTN...AND THAT MAY BE ENUF TO
BREAK THE CAP. WE/LL SEE.
LATER TONIGHT...AS WITH THE CONVECTION...FCST SNDGS AND MOISTURE
PROGS ON THE NAM AND GFS ARE VAGUE ON HOW MUCH CLOUD COVER WILL
LINGER OVERNIGHT. ANOTHER (STRONGER) VORT MAX...CURRENTLY OVER
MO...WILL PROVIDE DECENT QG FORCING LATE TNGT INTO WED MORNING. THIS
FEATURE WILL LIKELY KEEP SOME MID-HIGH CLOUDS AROUND. MEANWHILE...A
COLD FRONT WILL PUSH INTO THE AREA TOWARD DAYBREAK...HELPING KEEP
THINGS MIXED. SO TEMPS WILL BE NEAR NORMAL WITH PROBABLY NOT MUCH IN
THE WAY OF FOG. I ALSO KEEP A LINGERING SLGT CHC TO LOW-END CHC POP
DUE TO THE PASSAGE OF THE VORT MAX.
WEDNESDAY...THE COLD FRONT SHUD BE ABLE TO PUSH THRU THE REST OF THE
CWFA DURING THE DAY. GUIDANCE DOES TRY TO DEVELOP A LITTLE
CONVECTION ACRS MAINLY THE SE ZONES WITH DAYTIME HEATING NEAR THE
FRONT. OTHERWISE...SHUD BE A RELATIVELY DRY DAY WITH DECREASING
CLOUDS AND HIGHS NEAR NORMAL.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...ZONAL FLOW DEVELOPS FOR THU AS SHORT WAVE
MOVES EAST OF THE AREA. SFC HIGH PRESSURE BUILDS IN AS WELL. EXPECT
DRYING LOW LEVELS AND WARMING MID LEVELS THU HELPING TO CAP THE
ATMOS. SHUD BE A DRY FCST WITH LOWS A LITTLE BELOW NORMAL AND HIGHS
NEAR NORMAL. HEIGHTS FALL FRI AS SHORT WAVES DIVE TOWARD THE AREA.
THIS HELPS PUSH A COLD FRONT FROM THE OH VALLEY TO JUST WEST OF THE
CWFA. LEE TROF DEVELOPS TO HELP PRODUCE LOW LEVEL CONVERGENCE. UPPER
DIVERGENCE BEGINS TO INCREASE AS UPPER JET MOVES TOWARD THE AREA AS
WELL. EXPECT INSTABILITY TO RETURN WITH MOISTENING LOW LEVELS AND
COOLING MID LEVELS. BEST CHC FOR PRECIP WILL BE OVER THE MTNS WHERE
MOISTURE AND FORCING ARE HIGHER...BUT SCT CONVECTION SHUD DEVELOP
ALL AREAS BY LATE AFTERNOON. LOWS THU NITE RISE TO AROUND NORMAL
WITH HIGHS FRIDAY NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM TUESDAY...MUCH BETTER AGREEMENT BETWEEN THE 12Z GFS AND
THE 00Z ECMWF REGARDING THE DEVELOPING LONG WAVE TROF OVER THE ERN
CONUS THAN BETWEEN THE 06Z GFS AND 00Z ECMWF. AS MENTIONED ABOVE...
LONG WAVE TROF DEVELOPS OVER THE ERN CONUS AND REMAINS IN PLACE THRU
THE PERIOD. A SERIES OF WEAK SHORT WAVES MOVE THRU THE FLOW WITH THE
STRONGEST ON MONDAY. THE GFS THEN SHIFTS THE AXIS OF THE LONG WAVE
EAST ON TUE WHILE THE ECMWF HOLDS IN IN PLACE. AT THE SFC..A COLD
FRONT MOVES ACROSS THE AREA SAT...THEN STALLS TO OUR EAST AND SOUTH
THRU THE PERIOD. THE WAVE ON MONDAY MAY HELP DRAG THE FRONT BACK
TOWARD THE AREA BEFORE IT PUSHES SOUTH AND EAST OF US AGAIN FOR TUE.
GOOD AGREEMENT ON AT LEAST SCT POP SAT WITH THE FRONT...THEN
GUIDANCE DIFFERS FROM DAY TO DAY WITH PRECIP POTENTIAL DEPENDING ON
WHERE ANY WAVES MOVE ALONG THE FRONT AND IF THEY CAN PULL MOISTURE
BACK NORTH INTO THE CWFA. HAVE GONE WITH SCT POP SAT...SLIGHT CHC
SUN/MON THEN DRY TUE. TEMPS REMAIN NEARLY STEADY NEAR TO SLIGHTLY
BELOW NORMAL SAT THRU MON...THEN RISE BACK TO NEAR NORMAL FOR TUE.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
AT KCLT...A LOW CONFIDENCE FCST NEXT 24 HOURS...AS MODELS HAVING
TOUGH TIME WITH CONVECTION AND CLOUD COVER OVERALL. BASED ON THE
LATEST TRENDS...THINK CONVECTION WILL GET A LATE START IN THE NC
MTNS...WITH ACTIVITY NOT REACHING THE VICINITY UNTIL CLOSER TO 00Z.
SO I PUSHED THE TEMPO BACK TO 00Z. THEN AFTER 03Z...STILL A PROB30
FOR A COUPLE MORE HOURS. MEANWHILE...SW WINDS WILL BE AROUND 10
KNOTS OR SO WITH POSSIBLY A FEW GUSTS IN THE 15-18 KT RANGE. WIND
DECREASE TO UNDER 5 KNOTS AFTER SUNSET. GUIDANCE A BIT VAGUE ON HOW
MUCH MID AND HIGH CLOUDS LINGER OVERNIGHT. STILL EXPECT A FAIR
AMT...SO BETWEEN WINDS AND CLOUD COVER...NO FOG IS EXPECTED EARLY
WEDNESDAY. A WIND SHIFT TO NW WITH THE ARRIVAL OF A COLD FRONT IS
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD STAY FAIRLY LIGHT.
ELSEWHERE...CONVECTION SLOW TO GET GOING...SO TEMPO GROUPS AND VCTS
MENTIONS HAVE BEEN PUSHED BACK AT ALL SITES. CONFIDENCE ON TIMING
AND COVERAGE IS STILL LOW. AS A COLD FRONT MOVES THROUGH EARLY
WEDNESDAY MORNING...THE MODELS SHOW BREAKS IN LOW VFR CLOUD COVER.
SW WINDS AROUND 10 KNOTS WITH OCCASIONAL LOW-END GUSTS TODAY (EXCEPT
AT KAVL)...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY...EVEN THO GUIDANCE DOES
HAVE FOG IN THE MTN VALLEYS. A FRONTAL PASSAGE AND A WIND SHIFT ARE
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD REMAIN LIGHT.
OUTLOOK...THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE
REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK. A COLD FRONT
WILL BRING SOME MOISTURE TO THE AREA LATE FRIDAY INTO SATURDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...NED
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
251 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER BRIEFLY BEFORE THE NEXT COLD
FRONT MOVES TOWARD THE CAROLINAS LATE FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 145 PM...POPS HAD TO BE ADJUSTED AGAIN TO CHASE TRENDS. A
HEALTHY CU FIELD CAN BE SEEN ON VISIBLE...BUT JUST DOESN/T SEEM TO
BE ABLE TO BREAK THRU. THE 13Z HRRR IS THE CLOSEST TO REALITY...AND
IT REALLY ONLY HAS A FEW CELLS DEVELOPING ACRS THE NC MTNS THRU THE
AFTN HOURS. SO POPS WERE PUSHED BACK TO LATE AFTN/EVE...WHICH ARE
PROBABLY STILL OVERDONE. TEMPS ARE STILL LAGGING. ONE THING TO NOTE
IS THAT THE MODIFIED FFC SOUNDING THIS MORNING SHOWED THAT A FCST
MAX TEMP OF 87-89 STILL RESULTED IN SOME CIN. STILL EXPECT A VORT
MAX TO ENTER THE AREA LATER THIS AFTN...AND THAT MAY BE ENUF TO
BREAK THE CAP. WE/LL SEE.
LATER TONIGHT...AS WITH THE CONVECTION...FCST SNDGS AND MOISTURE
PROGS ON THE NAM AND GFS ARE VAGUE ON HOW MUCH CLOUD COVER WILL
LINGER OVERNIGHT. ANOTHER (STRONGER) VORT MAX...CURRENTLY OVER
MO...WILL PROVIDE DECENT QG FORCING LATE TNGT INTO WED MORNING. THIS
FEATURE WILL LIKELY KEEP SOME MID-HIGH CLOUDS AROUND. MEANWHILE...A
COLD FRONT WILL PUSH INTO THE AREA TOWARD DAYBREAK...HELPING KEEP
THINGS MIXED. SO TEMPS WILL BE NEAR NORMAL WITH PROBABLY NOT MUCH IN
THE WAY OF FOG. I ALSO KEEP A LINGERING SLGT CHC TO LOW-END CHC POP
DUE TO THE PASSAGE OF THE VORT MAX.
WEDNESDAY...THE COLD FRONT SHUD BE ABLE TO PUSH THRU THE REST OF THE
CWFA DURING THE DAY. GUIDANCE DOES TRY TO DEVELOP A LITTLE
CONVECTION ACRS MAINLY THE SE ZONES WITH DAYTIME HEATING NEAR THE
FRONT. OTHERWISE...SHUD BE A RELATIVELY DRY DAY WITH DECREASING
CLOUDS AND HIGHS NEAR NORMAL.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...ZONAL FLOW DEVELOPS FOR THU AS SHORT WAVE
MOVES EAST OF THE AREA. SFC HIGH PRESSURE BUILDS IN AS WELL. EXPECT
DRYING LOW LEVELS AND WARMING MID LEVELS THU HELPING TO CAP THE
ATMOS. SHUD BE A DRY FCST WITH LOWS A LITTLE BELOW NORMAL AND HIGHS
NEAR NORMAL. HEIGHTS FALL FRI AS SHORT WAVES DIVE TOWARD THE AREA.
THIS HELPS PUSH A COLD FRONT FROM THE OH VALLEY TO JUST WEST OF THE
CWFA. LEE TROF DEVELOPS TO HELP PRODUCE LOW LEVEL CONVERGENCE. UPPER
DIVERGENCE BEGINS TO INCREASE AS UPPER JET MOVES TOWARD THE AREA AS
WELL. EXPECT INSTABILITY TO RETURN WITH MOISTENING LOW LEVELS AND
COOLING MID LEVELS. BEST CHC FOR PRECIP WILL BE OVER THE MTNS WHERE
MOISTURE AND FORCING ARE HIGHER...BUT SCT CONVECTION SHUD DEVELOP
ALL AREAS BY LATE AFTERNOON. LOWS THU NITE RISE TO AROUND NORMAL
WITH HIGHS FRIDAY NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM TUESDAY...MUCH BETTER AGREEMENT BETWEEN THE 12Z GFS AND
THE 00Z ECMWF REGARDING THE DEVELOPING LONG WAVE TROF OVER THE ERN
CONUS THAN BETWEEN THE 06Z GFS AND 00Z ECMWF. AS MENTIONED ABOVE...
LONG WAVE TROF DEVELOPS OVER THE ERN CONUS AND REMAINS IN PLACE THRU
THE PERIOD. A SERIES OF WEAK SHORT WAVES MOVE THRU THE FLOW WITH THE
STRONGEST ON MONDAY. THE GFS THEN SHIFTS THE AXIS OF THE LONG WAVE
EAST ON TUE WHILE THE ECMWF HOLDS IN IN PLACE. AT THE SFC..A COLD
FRONT MOVES ACROSS THE AREA SAT...THEN STALLS TO OUR EAST AND SOUTH
THRU THE PERIOD. THE WAVE ON MONDAY MAY HELP DRAG THE FRONT BACK
TOWARD THE AREA BEFORE IT PUSHES SOUTH AND EAST OF US AGAIN FOR TUE.
GOOD AGREEMENT ON AT LEAST SCT POP SAT WITH THE FRONT...THEN
GUIDANCE DIFFERS FROM DAY TO DAY WITH PRECIP POTENTIAL DEPENDING ON
WHERE ANY WAVES MOVE ALONG THE FRONT AND IF THEY CAN PULL MOISTURE
BACK NORTH INTO THE CWFA. HAVE GONE WITH SCT POP SAT...SLIGHT CHC
SUN/MON THEN DRY TUE. TEMPS REMAIN NEARLY STEADY NEAR TO SLIGHTLY
BELOW NORMAL SAT THRU MON...THEN RISE BACK TO NEAR NORMAL FOR TUE.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
AT KCLT...A LOW CONFIDENCE FCST NEXT 24 HOURS...AS MODELS HAVING
TOUGH TIME WITH CONVECTION AND CLOUD COVER OVERALL. BASED ON THE
LATEST TRENDS...THINK CONVECTION WILL GET A LATE START IN THE NC
MTNS...WITH ACTIVITY NOT REACHING THE VICINITY UNTIL CLOSER TO 00Z.
SO I PUSHED THE TEMPO BACK TO 00Z. THEN AFTER 03Z...STILL A PROB30
FOR A COUPLE MORE HOURS. MEANWHILE...SW WINDS WILL BE AROUND 10
KNOTS OR SO WITH POSSIBLY A FEW GUSTS IN THE 15-18 KT RANGE. WIND
DECREASE TO UNDER 5 KNOTS AFTER SUNSET. GUIDANCE A BIT VAGUE ON HOW
MUCH MID AND HIGH CLOUDS LINGER OVERNIGHT. STILL EXPECT A FAIR
AMT...SO BETWEEN WINDS AND CLOUD COVER...NO FOG IS EXPECTED EARLY
WEDNESDAY. A WIND SHIFT TO NW WITH THE ARRIVAL OF A COLD FRONT IS
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD STAY FAIRLY LIGHT.
ELSEWHERE...CONVECTION SLOW TO GET GOING...SO TEMPO GROUPS AND VCTS
MENTIONS HAVE BEEN PUSHED BACK AT ALL SITES. CONFIDENCE ON TIMING
AND COVERAGE IS STILL LOW. AS A COLD FRONT MOVES THROUGH EARLY
WEDNESDAY MORNING...THE MODELS SHOW BREAKS IN LOW VFR CLOUD COVER.
SW WINDS AROUND 10 KNOTS WITH OCCASIONAL LOW-END GUSTS TODAY (EXCEPT
AT KAVL)...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY...EVEN THO GUIDANCE DOES
HAVE FOG IN THE MTN VALLEYS. A FRONTAL PASSAGE AND A WIND SHIFT ARE
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD REMAIN LIGHT.
OUTLOOK...THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE
REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK. A COLD FRONT
WILL BRING SOME MOISTURE TO THE AREA LATE FRIDAY INTO SATURDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...ARK
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
200 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER BRIEFLY BEFORE THE NEXT COLD
FRONT MOVES ACROSS THE CAROLINAS LATE FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 145 PM...POPS HAD TO BE ADJUSTED AGAIN TO CHASE TRENDS. A
HEALTHY CU FIELD CAN BE SEEN ON VISIBLE...BUT JUST DOESN/T SEEM TO
BE ABLE TO BREAK THRU. THE 13Z HRRR IS THE CLOSEST TO REALITY...AND
IT REALLY ONLY HAS A FEW CELLS DEVELOPING ACRS THE NC MTNS THRU THE
AFTN HOURS. SO POPS WERE PUSHED BACK TO LATE AFTN/EVE...WHICH ARE
PROBABLY STILL OVERDONE. TEMPS ARE STILL LAGGING. ONE THING TO NOTE
IS THAT THE MODIFIED FFC SOUNDING THIS MORNING SHOWED THAT A FCST
MAX TEMP OF 87-89 STILL RESULTED IN SOME CIN. STILL EXPECT A VORT
MAX TO ENTER THE AREA LATER THIS AFTN...AND THAT MAY BE ENUF TO
BREAK THE CAP. WE/LL SEE.
LATER TONIGHT...AS WITH THE CONVECTION...FCST SNDGS AND MOISTURE
PROGS ON THE NAM AND GFS ARE VAGUE ON HOW MUCH CLOUD COVER WILL
LINGER OVERNIGHT. ANOTHER (STRONGER) VORT MAX...CURRENTLY OVER
MO...WILL PROVIDE DECENT QG FORCING LATE TNGT INTO WED MORNING. THIS
FEATURE WILL LIKELY KEEP SOME MID-HIGH CLOUDS AROUND. MEANWHILE...A
COLD FRONT WILL PUSH INTO THE AREA TOWARD DAYBREAK...HELPING KEEP
THINGS MIXED. SO TEMPS WILL BE NEAR NORMAL WITH PROBABLY NOT MUCH IN
THE WAY OF FOG. I ALSO KEEP A LINGERING SLGT CHC TO LOW-END CHC POP
DUE TO THE PASSAGE OF THE VORT MAX.
WEDNESDAY...THE COLD FRONT SHUD BE ABLE TO PUSH THRU THE REST OF THE
CWFA DURING THE DAY. GUIDANCE DOES TRY TO DEVELOP A LITTLE
CONVECTION ACRS MAINLY THE SE ZONES WITH DAYTIME HEATING NEAR THE
FRONT. OTHERWISE...SHUD BE A RELATIVELY DRY DAY WITH DECREASING
CLOUDS AND HIGHS NEAR NORMAL.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 205 AM TUESDAY...UPPER HEIGHTS BEGIN TO RISE EARLY WED AND
FLAT RIDGING WILL PREVAIL THROUGH MOST OF THE SHORT TERM. SOME
LINGERING SHOWERS FROM TUE/S FRONTAL SYSTEM COULD AFFECT THE ERN
ZONES AND MORESO THE NC MTNS EARLY WED...BUT THE MODELS HAVE
DIFFERING IDEAS ON THIS SO LITTLE CHANGE WAS MADE TO THE GOING SLT
CHANCES. EXPECT GOOD INSOLATION WED/THU TO ALLOW MAX TEMPS TO REACH
A CAT OR SO ABOVE NORMAL. THE GOOD NEWS IS THE LLVL FLOW WILL REMAIN
W/LY AND AFTERNOON TD/S WILL MIX OUT TO AROUND 60 F...MAKING FOR
WARM BUT RATHER PLEASANTLY DRY CONDITIONS EACH DAY. ISOL TO SCT
SHOWERY ACTIVITY SHOULD DEVELOP ACROSS THE WRN ZONES THU NIGHT AS A
PREFRONTAL TROF BEGINS TO DEEPEN AND MOVES TOWARD THE AREA.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 130 AM EDT TUESDAY...GOOD AGREEMENT IS HAD BTW THE LATEST MID
RANGE MODELS WRT THE LARGE UPPER LOW AND THE EVOLUTION OF THE SFC
FRONT APPROACHING THE NC MTNS BY SAT. BEFORE THAT...A SMALL SCALE
UPPER RIDGE BREAKS DOWN OVER THE FCST AREA AND LLVL WINDS RESPOND
OUT OF THE SW ALLOWING A MOISTENING OF THE LLVLS AND AN INCREASE IN
MECHANICAL LIFT ACROSS THE HIGHER TERRAIN. DEWPOINTS WILL RETURN TO
THE MID TO UPPER 60S AND SCT AFTERNOON CONVECTION IS LIKELY ACROSS
THE MAJORITY OF THE AREA INTO THE EVENING. THE PREFRONTAL TROF WILL
PUSH INTO THE AREA EARLY SAT AND -SHRA WILL BE EXPECTED EARLY ON
ACROSS THE NC MTNS...THEN SPREADING EAST AS THE DAY PROGRESSES.
MODEL SOUNDINGS STILL INDICATE LOWER END SBCAPE AND MUCAPE...ESP
ACROSS THE NON/MTNS...WHILE DEEP LAYERED SHEAR REACHES A RESPECTABLE
30 KTS OR SO. THUS...STRONG STORMS ARE PROBABLE WITH A FEW POSSIBLY
REACHING SEVERE CRITERIA SAT AFTERNOON/EVENING. HIGH PRESSURE BUILDS
IN EARLY SUN AND REMAINS THROUGH MON WHICH WILL MAKE FOR A COUPLE
DRY DAYS. MAX TEMPS WILL BE RIGHT AROUND NORMAL FRI AND A FEW
DEGREES COOL SAT WITH ALL THE CLOUD COVER. SUN AND MON WILL
EXPERIENCE AN AIRMASS MIX...SO MAXES SHOULD BE HELD A COUPLE CATS
BELOW NORMAL EACH OF THOSE DAYS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...A LOW CONFIDENCE FCST NEXT 24 HOURS...AS MODELS HAVING
TOUGH TIME WITH CONVECTION AND CLOUD COVER OVERALL. BASED ON THE
LATEST TRENDS...THINK CONVECTION WILL GET A LATE START IN THE NC
MTNS...WITH ACTIVITY NOT REACHING THE VICINITY UNTIL CLOSER TO 00Z.
SO I PUSHED THE TEMPO BACK TO 00Z. THEN AFTER 03Z...STILL A PROB30
FOR A COUPLE MORE HOURS. MEANWHILE...SW WINDS WILL BE AROUND 10
KNOTS OR SO WITH POSSIBLY A FEW GUSTS IN THE 15-18 KT RANGE. WIND
DECREASE TO UNDER 5 KNOTS AFTER SUNSET. GUIDANCE A BIT VAGUE ON HOW
MUCH MID AND HIGH CLOUDS LINGER OVERNIGHT. STILL EXPECT A FAIR
AMT...SO BETWEEN WINDS AND CLOUD COVER...NO FOG IS EXPECTED EARLY
WEDNESDAY. A WIND SHIFT TO NW WITH THE ARRIVAL OF A COLD FRONT IS
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD STAY FAIRLY LIGHT.
ELSEWHERE...CONVECTION SLOW TO GET GOING...SO TEMPO GROUPS AND VCTS
MENTIONS HAVE BEEN PUSHED BACK AT ALL SITES. CONFIDENCE ON TIMING
AND COVERAGE IS STILL LOW. AS A COLD FRONT MOVES THROUGH EARLY
WEDNESDAY MORNING...THE MODELS SHOW BREAKS IN LOW VFR CLOUD COVER.
SW WINDS AROUND 10 KNOTS WITH OCCASIONAL LOW-END GUSTS TODAY (EXCEPT
AT KAVL)...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY...EVEN THO GUIDANCE DOES
HAVE FOG IN THE MTN VALLEYS. A FRONTAL PASSAGE AND A WIND SHIFT ARE
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD REMAIN LIGHT.
OUTLOOK...THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE
REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK. A COLD FRONT
WILL BRING SOME MOISTURE TO THE AREA LATE FRIDAY INTO SATURDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...ARK
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...ARK
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
339 PM CDT TUE AUG 14 2012
.DISCUSSION.../ISSUED AT 339 PM CDT/
COMPLEX WEAK TROUGH WORKING ACROSS THE EASTERN DAKOTAS THIS
AFTERNOON. ONE CORE DIGGING SOUTHWARD THROUGH EASTERN
NEBRASKA...WITH COOL AIR POOL LEFTOVER AROUND THE KYKN AREA FROM
EARLIER SHOWERS/THUNDERSTORMS TO THE SOUTH. CAN SEE A SECONDARY
IMPULSE DROPPING SOUTHEAST FROM SOUTHERN NORTH DAKOTA TOWARD
SOUTHWEST MINNESOTA. SUBTLE BOUNDARY ON RADAR NORTH OF KFSD...AND
BEST LOWER TO MID LEVEL BOUNDARY WILL REMAIN JUST NORTH AND EAST OF
THE AREA THROUGH THE EVENING HOURS BEFORE STARTING TO NUDGE
NORTHEAST. ELEVATED THETA E ADVECTION FOCUSES THROUGH THE NORTHEAST
HALF OF THE AREA OVERNIGHT...AND CONCENTRATION TO POPS MADE THROUGH
THAT AREA... WINDING DOWN LATER IN THE NIGHT. HRRR HAS SOME SUPPORT
TO DEVELOPMENT DURING THE EVENING IN THIS AREA...KICKING UP AS THE
LOW LEVEL JET STARTS TO INCREASE AROUND SUNSET.
ON WEDNESDAY...MUCH OF THE DAY LOOKS TO BE INERT WEATHERWISE...
WITH VERY WARM 700 HPA TEMPERATURES AND SURFACE FRONT APPROACHING
FROM THE WEST. 3 HOUR PRESSURE RISES OF 5-6 HPA/3H WILL PRESS IN
BEHIND BOUNDARY...WITH MIXED LAYER WINDS TOPPING OUT 30-35 KNOTS.
HAVE ISSUED A WIND ADVISORY FOR THE FAR SOUTHWEST AREAS...WITH A
POTENTIAL THAT MAY NEED A SLIGHT EASTWARD EXPANSION TOWARD THE JAMES
VALLEY.
HARD TO PICTURE SURFACE BOUNDARY GOING CONVECTIVE WITH A MID
AFTERNOON INHIBITION OF 200-300 J/KG...SO MAY END UP GOING A BIT
BEHIND BOUNDARY INITIALLY...SO HEDGED POPS A BIT FURTHER BACK
WESTWARD FROM EXPECTED BOUNDARY LOCATION...WHICH SHOULD BE NEAR A
KOTG TO KLCG LINE BY 00Z. DEEP LAYER SHEAR AROUND 40 KNOTS WILL
SUGGEST A GOOD POTENTIAL FOR ORGANIZATION AND DISCRETE STRUCTURES
INITIALLY WITH CROSS BOUNDARY SHEAR. ONE PROBLEM WILL BE THE
AVAILABLE MOISTURE...AS DO EXPECT THAT PREFRONTAL AREAS WILL MIX
VERY WELL...WELL INTO THE 90S TEMPWISE...WITH DEWPOINTS PERHAPS INTO
THE LOWER 50S. CAPE WILL PROBABLY BE LIMITED TO 1000-1500 J/KG.
SHOULD BE ENOUGH FOR A HAIL/WIND THREAT FOR THE VERY LATE AFTERNOON.
/CHAPMAN
WEDNESDAY NIGHT WILL SEE THE CONVECTION ALONG THE FRONT RACE QUICKLY
EAST OUT OF THE CWA...WILL HAVE SOME LOWER POPS IN THE FAR EASTERN
PART OF THE CWA THROUGH ABOUT 9Z IN CASE BOUNDARY IS A LITTLE SLOWER
BUT OVERALL MOST ACTIVITY LIKELY TO BE FROM ABOUT 23Z THROUGH 4Z AND
MAINLY IN SOUTHWEST MINNESOTA AND NORTHWEST IOWA. WILL MAINTAIN A
THREAT FOR SEVERE WEATHER THROUGH THIS TIME AS THE DEEPER BULK SHEAR
VALUES INCREASE TO ABOUT 40 KNOTS WITH FAIRLY STRONG CAPE VALUES.
COOLER AND DRIER AIR WILL PUSH IN BEHIND THE FRONT WITH BREEZY
EVENING CONDITIONS LEADING INTO A BIT OF A BREEZY AND COOL THURSDAY.
LOWS IN THE MID 50S WITH 10 TO 15 MPH WIND WILL LEAD TOWARDS HIGHS
THURSDAY FROM THE UPPER 60S IN SOUTHWEST MINNESOTA TO THE MID 70S IN
SOUTH CENTRAL SOUTH DAKOTA. EXPECTING A BIT OF CLOUD COVER TO LINGER
OVER THE SOOTH AND EAST PARTS OF THE CWA AS THE WAVE ROTATES
EASTWARD WHICH WILL AID IN LIMITING THE HIGH TEMPERATURE POTENTIAL.
FRIDAY MORNING PUTS THE AREA IN THE HEART OF THE COOLER AIR AS HIGH
PRESSURE SHOULD BE NEAR THE BIG SIOUX RIVER VALLEY AROUND 12Z
FRIDAY. UTILITY OF THE LOCAL EXTREME CLIMATOLOGY FITS WELL FOR
RECORD TO NEAR RECORD MORNING LOWS SO WILL AIM A LITTLE BELOW THE
COLDEST GUIDANCE WITH MOST AREAS DROPPING DOWN INTO THE LOWER TO
MIDDLE 40S.
FRIDAY WILL BE A FAIRLY COOL BUT VERY PLEASANT DAY WITH DRY AIR IN
PLACE...HIGH PRESSURE ONLY GRADUALLY SHIFTING SOUTHEAST AND 925MB
TEMPERATURES IN THE MID TO UPPER TEENS. THIS SHOULD BRING A MOSTLY
SUNNY DAY WITH HIGHS FROM THE LOWER TO MIDDLE 70S.
IN THE LATTER PERIODS(SAT/TUE)...MODELS FAIRLY AGREEABLE UPON
DEVELOPING A LARGE SCALE HUDSON BAY LOW...WITH RIDGING OVER THE
WESTERN UNITED STATES. THIS SUGGESTS NORMAL TO BELOW NORMAL
CONDITIONS WITH ONLY SPOTTY CHANCES FOR RAIN AND THUNDERSTORMS. THE
GFS IS THE MOST AGGRESSIVE AT DEVELOPING THIS LOW WHILE THE ECMWF
AND CANADIAN SUGGEST THAT A SHORTWAVE WILL ROUND THE RIDGE IN THE
WEST LATE IN THE PERIOD AND HELP EJECT THE HUDSON BAY LOW EASTWARD.
NOT BUYING INTO THIS SCENARIO COMPLETELY AS THIS WAVE COULD JUST
ROUND THE WESTERN SIDE OF THE HUDSON BAY LOW...FURTHER DEEPENING IT.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. BETTER THREAT
FOR CONVECTION LOOKS TO OCCUR THIS EVENING NORTH AND EAST OF THE
AREA...WITH LESS FORCING/CONVERGENCE OF MID LEVEL WIND TO THE SOUTH
AND WEST. HOWEVER...POTENTIAL FOR CONVECTION AT TAF SITES DEEMED TOO
LOW TO MENTION IN THE ONGOING SET...BUT DID ADD IN A COUPLE HOURS OF
SHOWERS FOR KSUX DURING THE MID TO LATE AFTERNOON ON PERIPHERY OF
CORE OF WAVE DIGGING THROUGH EASTERN NEBRASKA. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...WIND ADVISORY 18Z WED THROUGH 00Z WED FOR SDZ050-057-063.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
115 PM CDT TUE AUG 14 2012
.DISCUSSION.../ISSUED AT 115 PM CDT/
WEAK WAVE PUSHING SOUTHEAST THROUGH SOUTHERN SOUTH DAKOTA...WITH A
LONG HISTORY OF PRECIPITATION WHILE DIGGING SOUTHEAST OUT OF MONTANA.
EXPECT A BULK OF ACTIVITY TO SHIFT SOUTHEAST INTO EASTERN
NEBRASKA...AND KEPT HIGHEST POPS GOING ALONG THE MISSOURI RIVER
CORRIDOR THROUGH THE MID AFTERNOON. HOWEVER...A FAIRLY DISTINCT BAND
OF MID LEVEL INSTABILITY IN PLACE...AND GIVEN THE CONTINUATION OF
850-700 HPA THETA E ADVECTION...WILL PROBABLY FIND A LEAST A MINIMAL
THREAT OF MID BASED SHOWERS/ISOLATED THUNDER PUSHING EASTWARD DURING
THE AFTERNOON. HRRR A LITTLE OVERZEALOUS WITH PRECIPITATION...AS
TYPICAL...BUT IDEA THAT SOME THREAT SHIFTS EAST TOWARD A KMML TO
KSUX AXIS LATER IN THE DAY SEEMS REASONABLE...AS DOES POTENTIAL FOR
SOME DEVELOPMENT ON BACK EDGE OF CLOUDS BY LATER THIS AFTERNOON. AS
A RESULT OF THE MUCH MORE EXTENSIVE CLOUDS...DID LOWER SOME TEMPS 3
TO 5 DEGREES IN HEART OF THE AREA...BUT THE FAR EAST WITH DELAY IN
CLOUD ONSET...AND THE FAR WEST WILL BREAK OUT ENOUGH TO REACH
EARLIER POTENTIAL. UPDATES OUT. /CHAPMAN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. BETTER THREAT
FOR CONVECTION LOOKS TO OCCUR THIS EVENING NORTH AND EAST OF THE
AREA...WITH LESS FORCING/CONVERGENCE OF MID LEVEL WIND TO THE SOUTH
AND WEST. HOWEVER...POTENTIAL FOR CONVECTION AT TAF SITES DEEMED TOO
LOW TO MENTION IN THE ONGOING SET...BUT DID ADD IN A COUPLE HOURS OF
SHOWERS FOR KSUX DURING THE MID TO LATE AFTERNOON ON PERIPHERY OF
CORE OF WAVE DIGGING THROUGH EASTERN NEBRASKA. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 348 AM CDT/
YET ANOTHER PLEASANT SUMMER DAY EXPECTED ACROSS THE REGION TODAY
WITH SURFACE HIGH PRESSURE SLIPPING SOUTHEASTWARD INTO THE MID
MISSISSIPPI VALLEY BY THIS AFTERNOON. RETURN FLOW BEHIND THE HIGH
WILL BRING INCREASED SOUTHERLY FLOW...WHICH WILL BE GREATEST ACROSS
OUR WESTERN HALF. WINDS SHOULD BECOME BREEZY INTO THE JAMES VALLEY
AND WESTWARD. HIGHS WILL BE WARMER TODAY THAN IN PREVIOUS DAYS WITH
HIGHS MAINLY IN THE 80S...TO AROUND 90 IN SOUTH CENTRAL SOUTH
DAKOTA.
LOW LEVEL JET IS EXPECTED TO START KICKING IN THIS EVENING AND
OVERNIGHT ACROSS CENTRAL AND EASTERN PORTIONS OF THE FORECAST AREA.
THIS WILL BE COUPLED WITH A WEAK MID LEVEL WAVE WHICH TRACKS EAST
SOUTHEAST THROUGH THE FORECAST AREA. THIS SHOULD BE ENOUGH TO SQUEAK
OUT SOME ISOLATED THUNDERSTORMS...ALTHOUGH THE MEAGER MOISTURE COULD
WILL KEEP PRECIPITATION AMOUNTS WELL IN CHECK.
A BROAD CANADIAN UPPER TROUGH DIGGING INTO THE NORTHERN PLAINS WILL
DROP A FAIRLY POTENT COLD FRONT ACROSS THE NORTHERN PLAINS ON
WEDNESDAY. MIXY SOUTH SOUTHWEST WINDS AHEAD OF THE FRONT WILL USHER
IN THE WARMEST DAY OF THE WEEK AHEAD OF THE FRONT...WITH HIGHS IN
THE UPPER 80S TO MID 90S. THE FRONT WILL TRACK THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON AND EVENING...ACCOMPANIED BY A STRONG MID
LEVEL WAVE A FRONTOGENESIS. CAPPING SHOULD HOLD OFF INITIAL
CONVECTION IN OUR FAR WESTERN COUNTIES EARLY IN THE DAY...HOWEVER
WILL LIKELY SEE SCATTERED STORMS START FIRING EAST OF A YANKTON TO
BROOKINGS LINE IN THE LATE AFTERNOON AND BECOME MORE LIKELY ACROSS
NORTHWEST IOWA AND SOUTHWEST MINNESOTA IN THE EVENING HOURS AS
DAYTIME HEATING PEAKS AND THE 850 MB WAVE/FRONT DIGS INTO THE AREA.
STEEP LAPSE RATES APPROACHING 10C/KM...1500+ J/KG CAPE AND 40 KT
BULK SHEAR PER NAM FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR SOME
SEVERE STORMS WITH HAIL AND WIND CONCERNS...ALTHOUGH LOWER LEVEL
MOISTURE DOES APPEAR SOMEWHAT LACKING. WILL CONTINUE WITH LIKELY TO
CATEGORICAL POPS WEDNESDAY EVENING ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA.
DRY NORTHWEST FLOW SETTLES IN FOR THE LATER HALF OF THE WEEK.
TEMPERATURES WILL BE QUITE A BIT COOLER ON THURSDAY WITH BREEZY
NORTHERLY WINDS ADVECTING IN SOME BELOW NORMAL TEMPERATURES AND
CLOUDS DECREASING THROUGH THE MORNING. HIGHS WILL LIKELY ONLY BE IN
THE 70S ON THURSDAY AND FRIDAY...BUT WILL BE ON A GRADUAL WARMING
TREND THROUGH THE WEEKEND. OVERALL CONDITIONS LOOK PRETTY DRY WITH
ONLY SOME MINOR MOISTURE STARVED WAVES TRACKING THROUGH THE PLAINS
IN THE NORTHWEST FLOW. GFS PAINTS SOME LIGHT POPS ACROSS THE AREA
AROUND THE SATURDAY TIME FRAME...WHICH IS NOT WELL SUPPORTED IN THE
OTHER MODELS. WILL CONTINUE TO LEAVE OUT ANY MENTION OF POPS BEYOND
EARLY THURSDAY WITH LITTLE CONFIDENCE IN THE TIMING AND TRACK OF ANY
MID LEVEL WAVE THAT DOES MAKE AN APPEARANCE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1117 AM CDT TUE AUG 14 2012
.DISCUSSION.../ISSUED AT 1117 AM CDT/
WEAK WAVE PUSHING SOUTHEAST THROUGH SOUTHERN SOUTH DAKOTA...WITH A
LONG HISTORY OF PRECIPITATION WHILE DIGGING SOUTHEAST OUT OF MONTANA.
EXPECT A BULK OF ACTIVITY TO SHIFT SOUTHEAST INTO EASTERN
NEBRASKA...AND KEPT HIGHEST POPS GOING ALONG THE MISSOURI RIVER
CORRIDOR THROUGH THE MID AFTERNOON. HOWEVER...A FAIRLY DISTINCT BAND
OF MID LEVEL INSTABILITY IN PLACE...AND GIVEN THE CONTINUATION OF
850-700 HPA THETA E ADVECTION...WILL PROBABLY FIND A LEAST A MINIMAL
THREAT OF MID BASED SHRA/ISOLD TSRA PUSHING EASTWARD DURING THE
AFTERNOON. HRRR A LITTLE OVERZEALOUS WITH PRECIPTIATION...AS
TYPICAL...BUT IDEA THAT SOME THREAT SHIFTS EAST TOWARD A KMML TO
KSUX AXIS LATER IN THE DAY SEEMS REASONABLE...AS DOES POTENTIAL FOR
SOME DEVELOPMENT ON BACK EDGE OF CLOUDS BY LATER THIS AFTERNOON.
AS A RESULT OF THE MUCH MORE EXTENSIVE CLOUDS...DID LOWER SOME TEMPS
3 TO 5 DEGREES IN HEART OF THE AREA...BUT THE FAR EAST WITH DELAY IN
CLOUD ONSET...AND THE FAR WEST WILL BREAK OUT ENOUGH TO REACH
EARLIER POTENTIAL. UPDATES OUT.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. SOUTHERLY WINDS
WILL INCREASE THROUGHOUT THE DAY TODAY. LOW LEVEL JET WILL DEVELOP
TONIGHT...AND MAY CREATE ISOLATED THUNDERSTORMS ACROSS CENTRAL SOUTH
DAKOTA. HAVE A TEMPO IN KHON TAF FOR THIS. THERE IS A CHANCE FOR
THUNDERSTORMS IN KFSD TAF...BUT CONFIDENCE IS LOWER SO LEFT MENTION
OUT FOR NOW.
&&
.PREV DISCUSSION.../ISSUED AT 348 AM CDT/
YET ANOTHER PLEASANT SUMMER DAY EXPECTED ACROSS THE REGION TODAY
WITH SURFACE HIGH PRESSURE SLIPPING SOUTHEASTWARD INTO THE MID
MISSISSIPPI VALLEY BY THIS AFTERNOON. RETURN FLOW BEHIND THE HIGH
WILL BRING INCREASED SOUTHERLY FLOW...WHICH WILL BE GREATEST ACROSS
OUR WESTERN HALF. WINDS SHOULD BECOME BREEZY INTO THE JAMES VALLEY
AND WESTWARD. HIGHS WILL BE WARMER TODAY THAN IN PREVIOUS DAYS WITH
HIGHS MAINLY IN THE 80S...TO AROUND 90 IN SOUTH CENTRAL SOUTH
DAKOTA.
LOW LEVEL JET IS EXPECTED TO START KICKING IN THIS EVENING AND
OVERNIGHT ACROSS CENTRAL AND EASTERN PORTIONS OF THE FORECAST AREA.
THIS WILL BE COUPLED WITH A WEAK MID LEVEL WAVE WHICH TRACKS EAST
SOUTHEAST THROUGH THE FORECAST AREA. THIS SHOULD BE ENOUGH TO SQUEAK
OUT SOME ISOLATED THUNDERSTORMS...ALTHOUGH THE MEAGER MOISTURE COULD
WILL KEEP PRECIPITATION AMOUNTS WELL IN CHECK.
A BROAD CANADIAN UPPER TROUGH DIGGING INTO THE NORTHERN PLAINS WILL
DROP A FAIRLY POTENT COLD FRONT ACROSS THE NORTHERN PLAINS ON
WEDNESDAY. MIXY SOUTH SOUTHWEST WINDS AHEAD OF THE FRONT WILL USHER
IN THE WARMEST DAY OF THE WEEK AHEAD OF THE FRONT...WITH HIGHS IN
THE UPPER 80S TO MID 90S. THE FRONT WILL TRACK THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON AND EVENING...ACCOMPANIED BY A STRONG MID
LEVEL WAVE A FRONTOGENESIS. CAPPING SHOULD HOLD OFF INITIAL
CONVECTION IN OUR FAR WESTERN COUNTIES EARLY IN THE DAY...HOWEVER
WILL LIKELY SEE SCATTERED STORMS START FIRING EAST OF A YANKTON TO
BROOKINGS LINE IN THE LATE AFTERNOON AND BECOME MORE LIKELY ACROSS
NORTHWEST IOWA AND SOUTHWEST MINNESOTA IN THE EVENING HOURS AS
DAYTIME HEATING PEAKS AND THE 850 MB WAVE/FRONT DIGS INTO THE AREA.
STEEP LAPSE RATES APPROACHING 10C/KM...1500+ J/KG CAPE AND 40 KT
BULK SHEAR PER NAM FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR SOME
SEVERE STORMS WITH HAIL AND WIND CONCERNS...ALTHOUGH LOWER LEVEL
MOISTURE DOES APPEAR SOMEWHAT LACKING. WILL CONTINUE WITH LIKELY TO
CATEGORICAL POPS WEDNESDAY EVENING ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA.
DRY NORTHWEST FLOW SETTLES IN FOR THE LATER HALF OF THE WEEK.
TEMPERATURES WILL BE QUITE A BIT COOLER ON THURSDAY WITH BREEZY
NORTHERLY WINDS ADVECTING IN SOME BELOW NORMAL TEMPERATURES AND
CLOUDS DECREASING THROUGH THE MORNING. HIGHS WILL LIKELY ONLY BE IN
THE 70S ON THURSDAY AND FRIDAY...BUT WILL BE ON A GRADUAL WARMING
TREND THROUGH THE WEEKEND. OVERALL CONDITIONS LOOK PRETTY DRY WITH
ONLY SOME MINOR MOISTURE STARVED WAVES TRACKING THROUGH THE PLAINS
IN THE NORTHWEST FLOW. GFS PAINTS SOME LIGHT POPS ACROSS THE AREA
AROUND THE SATURDAY TIME FRAME...WHICH IS NOT WELL SUPPORTED IN THE
OTHER MODELS. WILL CONTINUE TO LEAVE OUT ANY MENTION OF POPS BEYOND
EARLY THURSDAY WITH LITTLE CONFIDENCE IN THE TIMING AND TRACK OF ANY
MID LEVEL WAVE THAT DOES MAKE AN APPEARANCE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
300 PM CDT TUE AUG 14 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY
300 PM CDT TUE AUG 14 2012
SHOWER/THUNDERSTORM CHANCES THROUGH THURSDAY AND TEMPERATURES ARE
THE MAIN CONCERN THROUGH THE SHORT TERM PERIOD.
LATEST WATER VAPOR IMAGERY ALONG WITH RAP 500MB HEIGHT ANALYSIS
SHOWS A COUPLE MID-LEVEL SHORTWAVE TROUGHS DROPPING THROUGH
NORTHWEST FLOW ALOFT ACROSS IA AND MN INTO NEBRASKA. MORE ENERGETIC
WAVE POISED TO AFFECT THE AREA IN THE NEXT 12-24 HOURS WAS MAKING
ITS WAY SOUTHEAST ACROSS THE ALBERTA ROCKIES. RADAR MOSAIC
SHOWING A BAND OF SCATTERED ELEVATED SHRA ACTIVITY ACROSS SOUTHEAST
ND INTO SOUTHWEST MN IN DECENT ISENTROPIC LIFT/MOISTURE TRANSPORT
AHEAD OF THE MN/NEB WAVE AND SURFACE WARM FRONT. MEANWHILE...
VISIBLE SATELLITE SHOWING AN EXPANSIVE FIELD OF CUMULUS ACROSS THE
LOCAL FORECAST AREA WITH INFLUENCE OF LINGERING COLD AIR ALOFT/STEEP
LAPSE RATES. TEMPERATURES ACROSS THE AREA AT 2 PM WERE IN THE 70S
TO LOWER 80S.
14.12Z NCEP MODELS/14.09Z SREF IN GOOD AGREEMENT WITH SYNOPTIC SETUP
THROUGH THE SHORT TERM PERIOD.
WILL BE WATCHING THE MN-NEB MID-LEVEL TROUGH AND SURFACE WARM FRONT
APPROACH THE AREA THIS EVENING/OVERNIGHT. NAM INDICATING
INCREASING/IMPRESSIVE 305K ISENTROPIC LIFT ALONG WITH STRONG
850-700MB FRONTOGENESIS/MOISTURE TRANSPORT AHEAD OF THE WARM FRONT
FOR ACCAS DEVELOPMENT ALONG WITH LIKELIHOOD OF SHRA/ISOLD T
ACTIVITY. BASED ON THIS SIGNAL...BUMPED POPS INTO 50-60 PERCENT
RANGE...WITH AREAS FROM LAKE CITY MN THROUGH LA CROSSE AND VIROQUA
LIKELY BEING THE AXIS OF HIGHEST PROBABILITIES. RIGHT NOW...IT
APPEARS THUNDER WILL BE ISOLATED IN NATURE WITH ELEVATED
CAPE/850-700MB ONLY APPROACHING 500J/KG.
GOOD CHANCE OF LINGERING SHRA/ISOLD THUNDER FOR AREAS ALONG/NORTH OF
I-94 WEDNESDAY MORNING AS THE WARM FRONT PUSHES THROUGH SOUTHEAST MN
INTO SOUTHWEST WI. APPEARS THE WARM FRONT WILL PUSH NORTHEAST OF THE
AREA BY AFTERNOON WITH THE AREA IN GENERAL WARM AIR ADVECTION AHEAD
OF A FAIRLY STRONG COLD FRONT PUSHING EAST ACROSS MN. KEPT SLIGHT
SHRA/TS CHANCES IN FOR AREAS ALONG/NORTHEAST OF I-94 THROUGH THE
AFTERNOON TO ACCOUNT FOR EXITING WARM FRONT. OTHERWISE...LOOK FOR
TEMPERATURES TO TOP OFF IN THE MIDDLE/UPPER 80S SOUTHWEST OF I-94
AND IN THE UPPER 70S/AROUND 80 NORTHEAST OF I-94 WITH MORE CLOUD
COVER THERE.
WILL HAVE TO WATCH FOR SEVERE POTENTIAL GOING INTO WEDNESDAY
EVENING. ANTICIPATING A FAIRLY SOLID LINE OF THUNDERSTORMS FIRING
ALONG THE COLD FRONT ACROSS MN INTO NORTHWEST IA BY LATER WEDNESDAY
AFTERNOON AS 0-3KM MUCAPE PUSH INTO THE 2500-5000J/KG RANGE ALONG
WITH AMPLE BULK SHEAR. THIS FRONT/LINE OF THUNDERSTORMS WILL BE
MOVING INTO THE AREA WEDNESDAY EVENING/OVERNIGHT. LINE SHOULD BE IN
A WEAKENING STATE OVERNIGHT AS CAPE WANES. HOWEVER..CANNOT RULE OUT
SEVERE HAIL/WIND THREAT FOR WESTERN PORTIONS OF THE FORECAST
AREA...MAINLY WEST OF A LINE FROM LAKE CITY AND ROCHESTER MN...TO
CHARLES CITY IA.
LOOK FOR THE COLD FRONT TO PUSH SOUTHEAST OF THE AREA BY THURSDAY
MORNING...TAKING THE BULK OF THE SHOWER/THUNDERSTORMS WITH IT.
HOWEVER...IT APPEARS A SECONDARY TROUGH/SURFACE REFLECTION OF
MID-LEVEL TROUGH LAGS THE COLD FRONT FOR SHRA/TS CHANCES LINGERING
THROUGH THE MORNING HOURS ACROSS THE ENTIRE AREA AND SOUTHEAST OF A
MAUSTON TO PRAIRIE DU CHIEN LINE DURING THE AFTERNOON.
MEANWHILE...VERY COLD AIR ALOFT/STEEPENING LAPSE RATES DURING THE
AFTERNOON ALSO EXPECTED TO KICK OFF QUITE A BIT OF CUMULUS ACROSS
THE REMAINDER OF THE AREA. HIGHS ON THURSDAY ONLY EXPECTED TO TOP
OFF IN THE UPPER 60S TO MIDDLE 70S.
THURSDAY NIGHT THROUGH FRIDAY WILL BE COOLER THAN NORMAL WITH DEEP
MID-LEVEL TROUGH DIGGING INTO THE CENTRAL CONUS/GREAT LAKES REGIONS.
CUMULUS FIELD SHOULD BE QUITE IMPRESSIVE FRIDAY AFTERNOON AS WELL
WITH THE COLD AIR ALOFT/STEEP LAPSE RATES. LOOK FOR LOWS IN THE
UPPER 40S/LOWER 50S THURSDAY NIGHT AND HIGHS ON FRIDAY IN THE UPPER
60S/LOWER 70S.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
300 PM CDT TUE AUG 14 2012
LATEST GFS/ECMWF SHOWING LONG WAVE TROUGH CARVED OUT ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY/GREAT LAKES REGION. STEEP LAPSE RATES
WILL EXIST THROUGH THE PERIOD WITH MODELS SHOWING A SHORTWAVE TROUGH
DROPPING IN ACROSS THE AREA SATURDAY FOR A TRIGGER FOR ISOLATED SHRA
DEVELOPMENT. LOOKS LIKE ANOTHER INNOCUOUS EMBEDDED SHORTWAVE TROUGH
WITHIN THE LONG WAVE/COLD TROUGH MAY BE ENOUGH ON SUNDAY FOR ANOTHER
ROUND OF ISOLATED SHOWERS. TEMPERATURES WILL REMAIN COOLER THAN
NORMAL UNDER THE TROUGH WITH HIGHS SATURDAY/SUNDAY TOPPING OFF IN
THE UPPER 60S/LOWER 70S. LOOK FOR THE TROUGH AXIS TO MOVE EAST OF
THE AREA ON MONDAY WITH SOME RIDGING ALOFT FOR DRIER AND SLIGHT
WARMER CONDITIONS. HIGHS ON MONDAY EXPECTED TO BE IN THE LOW/MID 70S.
THE GFS/EC DIVERGE ON THEIR SOLUTION ON TUESDAY. THE GFS BRINGS A
WING OF WARM AIR ADVECTION -SHRA/TS ACTIVITY INTO THE AREA WHEREAS
THE ECMWF MAINTAINS DRY SCENARIO IN WARM AIR ADVECTION. WENT WITH
MODEL CONSENSUS WHICH YIELDS A SLIGHT CHANCE OF SHOWER AND
THUNDERSTORMS. OTHERWISE...HIGHS ON TUESDAY EXPECTED TO WARM INTO
THE UPPER 70S/LOWER 80S.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1239 PM CDT TUE AUG 14 2012
WEAK 700 TO 600 FRONTOGENESIS WILL DEVELOP ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA LATE THIS AFTERNOON. THIS MAY RESULT
IN THE DEVELOPMENT OF ISOLATED SHOWERS AND THUNDERSTORMS. THE
AREAL COVERAGE AND CONFIDENCE WAS NOT HIGH ENOUGH TO ADD ANY
PRECIPITATION INTO THE KRST TAF.
FOR TONIGHT AND EARLY WEDNESDAY...STRONG FRONTOGENESIS DEVELOPS
ACROSS THE AREA. THIS IS IN RESPONSE TO WAVE MOVING OUT OF THE
DAKOTAS. IN ADDITION...THERE THERE WILL MODERATE TO STRONG 925 AND
850 MB MOISTURE TRANSPORT. AS A RESULT WENT WITH VCSH FROM 15.02Z
TO 15.13Z AT KRST...AND FROM 15.04Z TO 15.13Z AT KLSE.
CEILINGS WILL REMAIN BETWEEN 5 AND 10K THROUGH THIS PERIOD AND
VISIBILITIES WILL BE MAINLY ABOVE 6 MILES. HOWEVER COULD NOT RULE
OUT THE VISIBILITIES DROPPING DOWN BRIEFLY TO A MILE IN THE
HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS. CONFIDENCE WAS WAY TOO
LOW TO ADD THIS TO EITHER TAF SITE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
300 PM CDT TUE AUG 14 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...JSB
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
251 PM CDT TUE AUG 14 2012
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW WEAK HIGH
PRESSURE CENTERED OVER THE MISSISSIPPI VALLEY EARLY THIS AFTERNOON.
DIURNAL CU HAS BEEN FEISTY IN SPOTS WITH A FEW SHOWERS POPPING UP
OVER CENTRAL AND SOUTHERN WISCONSIN AND ALSO OVER THE UPPER
PENINSULA. MEANWHILE UPSTREAM...A BAND OF MID AND HIGH LEVEL CLOUDS
ARE PUSHING SOUTHEAST OVER MINNESOTA WHERE AREA RADARS ARE PICKING
UP ON WEAK RETURNS. EVEN FARTHER WEST..THE NEXT STORM SYSTEM IS
GATHERING STRENGTH NORTH OF THE MONTANA BORDER. AS RETURN FLOW
DEVELOPS ALOFT AND MID LEVEL CLOUDS ARRIVE...CLOUD COVER AND SMALL
PRECIP CHANCES ARE THE MAIN FORECAST CONCERNS OVER THE NEXT 24 HOURS.
TONIGHT...ANY SPOTTY SHOWERS THIS AFTERNOON WILL DIMINISH EARLY WITH
LOSS OF HEATING. OTHERWISE...NORTHWEST FLOW ALOFT WILL PREVAIL
ACROSS THE STATE AND BRING IN A BATCH OF MID AND HIGH CLOUDS FROM
MINNESOTA. WEAK LIFT ALONG THE 700MB THETAE GRADIENT MAY EVEN TRY
TO BRING A FEW SHOWERS TO CENTRAL WISCONSIN AFTER MIDNIGHT. WILL BE
FALLING OUT OF A MID DECK AND NOT CONFIDENT THAT ANY SHOWERS WILL
MEASURE...BUT WILL ADD A SLIGHT CHANCE TO THE FORECAST. WITH THE
CLOUD COVER...NOT EXPECTING A REPEAT OF THE FOG OVER N-C WISCONSIN
TONIGHT. A PARTLY TO MOSTLY CLOUDY NIGHT WITH LOWS RANGING THROUGH
THE 50S.
WEDNESDAY...AS A STRONG COLD FRONT MOVES INTO MINNESOTA...SW TO WEST
WINDS WILL BE WARM AND MOIST ADVECTING BETWEEN 850-700MB ACROSS THE
AREA OVER THE COURSE OF THE DAY. PROGGED SOUNDINGS DRY OUT BELOW
800MB...BUT PRECIP OVER THE EASTERN DAKOTAS AND MINNESOTA IS STILL
REACHING THE GROUND SO WILL EXPAND SLIGHT CHANCE OF SHOWERS TO THE
WESTERN FOX VALLEY. MID-LEVEL LAPSE RATE GRADIENT WILL ALSO NUDGE
INTO CENTRAL WISCONSIN INTO THE AFTERNOON...AND WILL KEEP A MENTION
OF ISOLATED THUNDER THERE. WITH THE BKN MID CLOUD DECK AND POTENTIAL
FOR LIGHT SHOWERS...TEMPERATURES WILL BE A STRUGGLE...MORE OR LESS
WENT WITH A BLEND OF THE PREVIOUS FORECAST WITH THE BCALLBLEND.
THIS WOULD PUT HIGHS IN THE UPPER 70S NORTH TO MID 80S SOUTH.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. THE MODELS ARE
NOW IN GOOD AGREEMENT WITH MOVING THE UPPER TROUGH FROM THE
CANADIAN ROCKIES TO GREAT LAKES OVER THE NEXT SEVERAL DAYS WITH A
REINFORCING UPPER TROUGH SATURDAY. THIS SHOULD KEEP CYCLONIC UPPER
FLOW ACROSS THE REGION THROUGH THE PERIOD WITH COOLER THAN NORMAL
TEMPERATURES AND DRY WEATHER MOST OF THE TIME.
SHOWERS AND THUNDERSTORMS WILL ARRIVE IN THE WESTERN PORTION OF
THE FORECAST AREA LATE WEDNESDAY NIGHT IN AN AREA OF UPPER
DIFFLUENCE AND LOW LEVEL WARM ADVECTION AND MOISTURE CONVERGENCE.
THE ARRIVAL OF THE FRONT DURING THE NIGHT TIME HOURS WILL MINIMIZE
THE SEVERAL THREAT. THE ACTIVITY WILL MOVE ACROSS EASTERN
WISCONSIN THURSDAY MORNING AND SHOULD EXIT THE AREA DURING THE
AFTERNOON. BREEZY AND COOLER THURSDAY NIGHT AND FRIDAY AS UPPER
HEIGHTS FALL AND BIG COOL SURFACE HIGH BUILDS IN FROM THE NORTHERN
PLAINS. CLEAR SKIES AND LIGHT WINDS SHOULD ALLOW TEMPERATURES TO
FALL INTO THE 30S IN THE USUAL COOL PLACES FRIDAY NIGHT WITH
POSSIBLE FROST.
AN UPPER TROUGH AND ASSOCIATED SURFACE FRONT WILL BRING A
REINFORCING PUSH OF COOL AIR SATURDAY AFTERNOON AND MAY BE
ACCOMPANIED BY A FEW SHOWERS. SCATTERED SHOWERS POSSIBLE ALSO
SUNDAY AFTERNOON IN CYCLONIC COLD UPPER FLOW.
&&
.AVIATION...FOR 12Z TAF ISSUANCE. SOME LIFR CIGS/FG WL LINGTER TO
ARND DAYBREAK TDA...THEN VFR CONDITIONS EXPECTED FOR THE REST OF
THE PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM