Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/12/12
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
445 AM PDT FRI AUG 10 2012
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
A HOT AIR MASS WILL REMAIN IN PLACE THROUGH THE WEEKEND DUE TO
HIGH PRESSURE OVER THE REGION. ISOLATED THUNDERSTORMS ARE
POSSIBLE FOR THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS AND
ANTELOPE VALLEY AS MONSOONAL MOISTURE OVER THE AREA. A TROUGH OF
LOW PRESSURE IS EXPECTED TO COOL TEMPERATURES CLOSER TO NORMAL
EARLY NEXT WEEK.
&&
.SHORT TERM (TODAY-SUNDAY)...
STRONG HIGH PRESSURE ALOFT REMAINS OVER THE REGION THIS MORNING
AS SOUTHEAST FLOW ALOFT ESTABLISHES. AT THE SURFACE...A THERMAL
TROUGH REMAIN OFFSHORE SOUTH OF POINT CONCEPTION AND IS SHIFT
ONSHORE NORTH OF POINT CONCEPTION. WITH THE SURFACE TROUGH
OFFSHORE...ANOTHER HOT DAY IS ON TAP SOUTH OF POINT CONCEPTION.
NORTH OF POINT CONCEPTION...INCREASING ONSHORE GRADIENTS SHOULD
PROVIDE SOME COOLING TODAY. AN EXCESSIVE HEAT WARNING REMAINS IN
EFFECT FOR THE LOS ANGELES AND VENTURA COUNTY VALLEYS AND
MOUNTAINS AND THE SANTA BARBARA COUNTY MOUNTAINS THROUGH THIS
EVENING. HEAT INDEX VALUES WILL BE NEAR DANGEROUS LEVELS AGAIN
TODAY OVER THESE AREAS.
THE MAIN CONCERN FOR THE TEMPERATURE FORECAST IS THE INCREASING
MID-LEVEL MOISTURE OCCURRING THIS MORNING. SOME COOLING CLOUD
TOPS ARE OCCURRING THIS MORNING AND THE CLOUD MASS IS EXPANDING
OVER THE AREA THIS MORNING. THIS COULD BE THE MAIN PROBLEM FOR
TODAY BEING THE WARMEST DAY OF THE WEEK AS PREVIOUSLY ADVERTISED.
IN ADDITION...SURFACE GRADIENTS TRENDS ARE STARTING TO REVERSE AND
BECOME MORE STRONGLY ONSHORE. WITH THESE TWO FACTORS IN
MIND...TEMPERATURES WERE COOLED SLIGHTLY AS THE AIR MASS COULD
COOL SLIGHTLY AS A RESULT.
THE CLOUD MASS OVER LOS ANGELES COUNTY THIS MORNING IS BEING
MONITORED CLOSELY WITH MODEL SOLUTIONS HANDLING THE MOISTURE
REASONABLY...BUT THE THERMAL PATTERN ALOFT SEEMS QUESTIONABLE.
GOES SATELLITE IMAGERY PLACES CLOUDS TOPS BETWEEN 20 AND 30 KFT
THIS MORNING WITH CLOUD TOPS COOLING...YET MODEL SOLUTIONS ALL
INDICATE TEMPERATURES INCREASING ALOFT. SOME CONCERN IS PLACED
WITH CLOUD MASS POSSIBLY BECOMING CONVECTIVE AS THE MORNING
PROGRESSES AND POPS NEEDING TO BE ADDED FOR THE COASTS AND
VALLEYS FOR TODAY. RAP MODEL SOLUTIONS SUGGEST SOME MID-LEVEL
CAPE DEVELOPING LATER THIS MORNING AND SOME POSITIVE OMEGA
OCCURRING IN THE LOWER LEVELS OF THE ATMOSPHERE. FOR NOW...THE
BEST APPROACH IS TO MONITOR THE SITUATION FOR THE POSSIBILITY OF
SHOWERS DEVELOPING THEN UPDATE AS NECESSARY.
THE AIR MASS WILL CONTINUE TO MOISTEN THROUGH THE WEEKEND AND
COOL AS A MONSOONAL FLOW PATTERN MATURES OVER THE AREA. THE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE SLIGHTLY FOR
SATURDAY AS MOISTURE INCREASES OVER THE AREA. THE HEAT WAVE WILL
SEE SOME REPRIEVE BUT IT WILL REMAIN QUITE WARM UNTIL SOUTHWEST
FLOW ALOFT ESTABLISHES OVER THE AREA EARLY NEXT WEEK.
.LONG TERM (MONDAY-THURSDAY)...
SOUTHWEST FLOW ALOFT SHOULD ESTABLISH OVER THE AREA BETWEEN SUNDAY
AND MONDAY AND BRING A COOLER AND DRIER AIR MASS TO THE AREA.
ONSHORE FLOW SHOULD INCREASE AND ALLOW FOR A STRONGER SEA BREEZE
EACH DAY...WITH A COOLING TREND PERSISTING INTO THURSDAY. SOME
LOWER VALLEY INTRUSION OF THE MARINE LAYER CLOUDS IS POSSIBLE
BETWEEN MONDAY NIGHT AND THURSDAY.
&&
.AVIATION...10/1145Z.
HIGH CONFIDENCE FOR VFR CONDITIONS ARE EXPECTED AT ALL INLAND
TERMINALS. AT COASTAL TERMINALS SOUTH OF POINT CONCEPTION...THERE IS
A 30 PERCENT CHANCE OF LIFR CONDITIONS AT COASTAL TERMINALS BETWEEN
12Z AND 16Z. NORTH OF POINT CONCEPTION...VLIFR TO LIFR CONDITIONS
WILL PERSIST THROUGH AT LEAST 14Z...THEN GRADUALLY IMPROVE TO VFR
THROUGH 17Z.
KLAX...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. THERE IS A
20 PERCENT CHANCE OF VLIFR TO LIFR CONDITIONS BETWEEN 12Z AND 15Z.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD WITH NO
WIND ISSUES.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...HALL
AVIATION...CK
SYNOPSIS...B/HALL
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
421 AM PDT FRI AUG 10 2012
.SYNOPSIS...
A HOT AIR MASS WILL REMAIN IN PLACE THROUGH THE WEEKEND DUE TO
HIGH PRESSURE OVER THE REGION. ISOLATED THUNDERSTORMS ARE
POSSIBLE FOR THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS AND
ANTELOPE VALLEY AS MONSOONAL MOISTURE OVER THE AREA. A TROUGH OF
LOW PRESSURE IS EXPECTED TO COOL TEMPERATURES CLOSER TO NORMAL
EARLY NEXT WEEK.
&&
.SHORT TERM (TODAY-SUNDAY)...
STRONG HIGH PRESSURE ALOFT REMAINS OVER THE REGION THIS MORNING
AS SOUTHEAST FLOW ALOFT ESTABLISHES. AT THE SURFACE...A THERMAL
TROUGH REMAIN OFFSHORE SOUTH OF POINT CONCEPTION AND IS SHIFT
ONSHORE NORTH OF POINT CONCEPTION. WITH THE SURFACE TROUGH
OFFSHORE...ANOTHER HOT DAY IS ON TAP SOUTH OF POINT CONCEPTION.
NORTH OF POINT CONCEPTION...INCREASING ONSHORE GRADIENTS SHOULD
PROVIDE SOME COOLING TODAY. AN EXCESSIVE HEAT WARNING REMAINS IN
EFFECT FOR THE LOS ANGELES AND VENTURA COUNTY VALLEYS AND
MOUNTAINS AND THE SANTA BARBARA COUNTY MOUNTAINS THROUGH THIS
EVENING. HEAT INDEX VALUES WILL BE NEAR DANGEROUS LEVELS AGAIN
TODAY OVER THESE AREAS.
THE MAIN CONCERN FOR THE TEMPERATURE FORECAST IS THE INCREASING
MID-LEVEL MOISTURE OCCURRING THIS MORNING. SOME COOLING CLOUD
TOPS ARE OCCURRING THIS MORNING AND THE CLOUD MASS IS EXPANDING
OVER THE AREA THIS MORNING. THIS COULD BE THE MAIN PROBLEM FOR
TODAY BEING THE WARMEST DAY OF THE WEEK AS PREVIOUSLY ADVERTISED.
IN ADDITION...SURFACE GRADIENTS TRENDS ARE STARTING TO REVERSE AND
BECOME MORE STRONGLY ONSHORE. WITH THESE TWO FACTORS IN
MIND...TEMPERATURES WERE COOLED SLIGHTLY AS THE AIR MASS COULD
COOL SLIGHTLY AS A RESULT.
THE CLOUD MASS OVER LOS ANGELES COUNTY THIS MORNING IS BEING
MONITORED CLOSELY WITH MODEL SOLUTIONS HANDLING THE MOISTURE
REASONABLY...BUT THE THERMAL PATTERN ALOFT SEEMS QUESTIONABLE.
GOES SATELLITE IMAGERY PLACES CLOUDS TOPS BETWEEN 20 AND 30 KFT
THIS MORNING WITH CLOUD TOPS COOLING...YET MODEL SOLUTIONS ALL
INDICATE TEMPERATURES INCREASING ALOFT. SOME CONCERN IS PLACED
WITH CLOUD MASS POSSIBLY BECOMING CONVECTIVE AS THE MORNING
PROGRESSES AND POPS NEEDING TO BE ADDED FOR THE COASTS AND
VALLEYS FOR TODAY. RAP MODEL SOLUTIONS SUGGEST SOME MID-LEVEL
CAPE DEVELOPING LATER THIS MORNING AND SOME POSITIVE OMEGA
OCCURRING IN THE LOWER LEVELS OF THE ATMOSPHERE. FOR NOW...THE
BEST APPROACH IS TO MONITOR THE SITUATION FOR THE POSSIBILITY OF
SHOWERS DEVELOPING THEN UPDATE AS NECESSARY.
THE AIR MASS WILL CONTINUE TO MOISTEN THROUGH THE WEEKEND AND
COOL AS A MONSOONAL FLOW PATTERN MATURES OVER THE AREA. THE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE SLIGHTLY FOR
SATURDAY AS MOISTURE INCREASES OVER THE AREA. THE HEAT WAVE WILL
SEE SOME REPRIEVE BUT IT WILL REMAIN QUITE WARM UNTIL SOUTHWEST
FLOW ALOFT ESTABLISHES OVER THE AREA EARLY NEXT WEEK.
.LONG TERM (MONDAY-THURSDAY)...
SOUTHWEST FLOW ALOFT SHOULD ESTABLISH OVER THE AREA BETWEEN SUNDAY
AND MONDAY AND BRING A COOLER AND DRIER AIR MASS TO THE AREA.
ONSHORE FLOW SHOULD INCREASE AND ALLOW FOR A STRONGER SEA BREEZE
EACH DAY...WITH A COOLING TREND PERSISTING INTO THURSDAY. SOME
LOWER VALLEY INTRUSION OF THE MARINE LAYER CLOUDS IS POSSIBLE
BETWEEN MONDAY NIGHT AND THURSDAY.
&&
.AVIATION...10/0625Z.
VFR CONDITIONS ARE EXPECTED AT ALL INLAND TERMINALS. AT COASTAL
TEMRINALS SOUTH OF POINT CONCEPTION...THERE IS A CHANCE OF LIFR
CONDITIONS AT COASTAL TERMINALS BETWEEN 08Z AND 16Z. NORTH OF POINT
CONCEPTION...VLIFR TO LIFR CONDITIONS WILL PERSIST THROUGH AT LEAST
14Z...THEN GRADUALLY IMPROVE TO VFR THROUGH 17Z.
KLAX...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. THERE IS A
20 PERCENT CHANCE OF VLIFR TO LIFR CONDITIONS BETWEEN 12Z AND 15Z.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD WITH NO
WIND ISSUES.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...HALL
AVIATION...HALL/KAPLAN
SYNOPSIS...B/HALL
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1028 AM MDT FRI AUG 10 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
MODELS CONTINUE TO SHOW EMBEDDED WAVES IN THE MOIST FLOW WHICH
COMBINING WITH AFTERNOON HEATING WILL BE THE FORCING MECHANISMS FOR
CONVECTION TODAY. RUC13 SHOWS THE BEST DYNAMICS MOVING ACROSS THE
EASTERN UTAH THIS MORNING INTO WEST-CENTRAL COLORADO BY THIS
AFTERNOON. EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCE OF
LOCALLY HEAVY RAIN ACROSS SOUTHERN AND EXTENDING NORTH ACROSS
CENTRAL SECTIONS TODAY. GUSTY OUTFLOW WINDS TO 50 MPH ARE ALSO
POSSIBLE NEAR STORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN
SECTIONS.
MORE ENERGETIC TROF MOVING INTO THE PACIFIC NORTHWEST LATE THIS
EVENING WILL BE PUSHING ACROSS THE NORTHERN ROCKIES BY THIS TIME
TOMORROW NIGHT. AS IT DOES SO THE UPPER HIGH WILL BE SUPPRESSED
SOUTH OF THE 4 CORNERS REGION AND BRINGING IN SOME STRONGER
WESTERLY FLOW AS THE GRADIENT TIGHTENS. THE GOES DERIVED SATELLITE
IMAGERY THIS MORNING IS SHOWING GOOD MOISTURE OVER SOUTHERN
CALIFORNIA/SOUTHERN NEVADA AND THE 320K MOISTURE TRANSPORT VECTS
SHOW THIS MOISTURE BEING PULLED INTO OUR CWA AS IT GETS CAUGHT UP
IN THE FASTER WESTERLIES. THERE IS NO DISTINCT OR STRONG FORCING
FOR ASCENT EVIDENT IN THE SHORT TERM MODELS OVERNIGHT. HOWEVER
BOTH GFS/NAM SHOW PWATS SURGING THROUGH THE EARLY MORNING HOURS
AND POT VORT MOVING ALONG THE NORTHERN BORDER AS UPPER JET MAX
APPROACHES SO THINK THERE WILL BE SOME LINGERING CONVECTION TO
DEAL WITH AND BOOSTED POPS SLIGHTLY AND FAVORED ACROSS THE
NORTHERN 1/3 OF THE CWA.
WITH MOISTURE IN PLACE SATURDAY ADDED DYNAMICS FROM AN UPPER LEVEL
SPEED MAX MOVING OVER NORTHERN COLORADO SHOULD LEAD TO ANOTHER
ACTIVE DAY...THOUGH MODELS ARE A LITTLE DIFFERENT ON TIMING AND
COVERAGE. NAM SOLN PVU FIELDS SHOW THE SHORT WAVE ENERGY DIPPING
INTO NORTHERN COLORADO EARLY IN THE DAY AS IT HAS A STRONGER SYSTEM
OVER THE NORTHERN ROCKIES...GFS NOT DEEPENING THE SYSTEM QUITE AS
MUCH AND KEEPS ANY SHORT WAVE FORCING JUST NORTH OF OUR BORDER. BY
AFTERNOON HOWEVER BOTH MODELS HAVE UPPER LEVEL DIVERGENCE OVER OUR
CENTRAL CWA AND WEAK SUBSIDENCE FILTERING INTO THE NORTH. THE
INHERITED POPS FOR SATURDAY COVERED THIS WELL AND MADE JUST A FEW
TWEAKS UPWARD WITH SLIGHT HIGHER CONFIDENCE. STILL CHANCE OF HEAVY
RAINFALL BUT STORM MOTIONS WILL BE ON THE INCREASE WHICH MAY ENHANCE
THE OUTFLOW WIND THREAT. TEMPERATURES SHOWING DIVERGING TREND IN
GUIDANCE WITH NAM LOWERING DUE TO BEING MORE ACTIVE. USED A BLEND
BUT GAVE MORE WEIGHT TO THE WARMER GUIDANCE ATTM.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
AS THE FLOW BECOME MORE NORTHWESTERLY IN THE WAKE OF THE NORTHERN
SYSTEM DRIER AIR LOOKS TO FILTER INTO THE CWA SATURDAY NIGHT WITH
PWATS KNOCKING BACK TO UNDER .75 OVER ALL BUT THE FAR SOUTHWESTERN
PORTION OF THE CWA. THIS SHOULD ALLOW CONVECTION TO TAPER OFF
OVERNIGHT AND LEAD TO COOLER LOW TEMPERATURES. THIS DRY AIR WILL BE
IN PLACE FOR ONLY A SHORT TIME AS PWATS LOOK TO REBOUND BY LATE
SUNDAY AS THE UPPER HIGH CENTERS OVER THE SOUTHERN HIGH PLAINS. WITH
A LATE MOISTURE PUSH SOME STORMS MAY MAKE IT INTO THE VALLEYS BUT
FOR THE MOST PART THINK MOST STORM WILL BE MORE ROOTED TO THE
TERRAIN.
NOT MUCH CHANGE IN THE WEATHER PATTERN INTO THE EXTENDED PERIOD...WITH
SOUTHERLY MOIST FLOW CONTINUING INTO THE EARLY WORK WEEK WITH A
CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS EXPECTED EACH DAY
THROUGH WEDNESDAY. MODELS ARE HINTING AT THE RIDGE BUILDING TO OUR
WEST BY THURSDAY WHICH WOULD GENERATE SLIGHTLY DRIER CONDITIONS BY
LATE IN THE WEEK WITH A DECREASING THREAT OF SHOWERS AND
THUNDERSTORMS. EXPECT SEASONABLY WARM TEMPERATURES THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1028 AM MDT FRI AUG 10 2012
EXPECT OCCASIONAL MVFR CONDITIONS AT KEGE AND KASE THIS AFTERNOON
AND EVENING AS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DEVELOP OVER AND NEAR THE MOUNTAINS. LOCAL HEAVY RAIN IS POSSIBLE
ALONG WITH WIND GUSTS TO 45 MPH. THUNDERSTORMS WILL AFFECT THE
VALLEYS AFTER 20Z. THE GREATEST AREAL COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL BE OVER SOUTHWEST CO AND SOUTHEAST UT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...15/MPM
LONG TERM...MPM
AVIATION...CC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
301 AM MDT FRI AUG 10 2012
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
MODELS CONTINUE TO SHOW EMBEDDED WAVES IN THE MOIST FLOW WHICH
COMBINING WITH AFTERNOON HEATING WILL BE THE FORCING MECHANISMS FOR
CONVECTION TODAY. RUC13 SHOWS THE BEST DYNAMICS MOVING ACROSS THE
EASTERN UTAH THIS MORNING INTO WEST-CENTRAL COLORADO BY THIS
AFTERNOON. EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCE OF
LOCALLY HEAVY RAIN ACROSS SOUTHERN AND EXTENDING NORTH ACROSS
CENTRAL SECTIONS TODAY. GUSTY OUTFLOW WINDS TO 50 MPH ARE ALSO
POSSIBLE NEAR STORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN
SECTIONS.
MORE ENERGETIC TROF MOVING INTO THE PACIFIC NORTHWEST LATE THIS
EVENING WILL BE PUSHING ACROSS THE NORTHERN ROCKIES BY THIS TIME
TOMORROW NIGHT. AS IT DOES SO THE UPPER HIGH WILL BE SUPPRESSED
SOUTH OF THE 4 CORNERS REGION AND BRINGING IN SOME STRONGER
WESTERLY FLOW AS THE GRADIENT TIGHTENS. THE GOES DERIVED SATELLITE
IMAGERY THIS MORNING IS SHOWING GOOD MOISTURE OVER SOUTHERN
CALIFORNIA/SOUTHERN NEVADA AND THE 320K MOISTURE TRANSPORT VECTS
SHOW THIS MOISTURE BEING PULLED INTO OUR CWA AS IT GETS CAUGHT UP
IN THE FASTER WESTERLIES. THERE IS NO DISTINCT OR STRONG FORCING
FOR ASCENT EVIDENT IN THE SHORT TERM MODELS OVERNIGHT. HOWEVER
BOTH GFS/NAM SHOW PWATS SURGING THROUGH THE EARLY MORNING HOURS
AND POT VORT MOVING ALONG THE NORTHERN BORDER AS UPPER JET MAX
APPROACHES SO THINK THERE WILL BE SOME LINGERING CONVECTION TO
DEAL WITH AND BOOSTED POPS SLIGHTLY AND FAVORED ACROSS THE
NORTHERN 1/3 OF THE CWA.
WITH MOISTURE IN PLACE SATURDAY ADDED DYNAMICS FROM AN UPPER LEVEL
SPEED MAX MOVING OVER NORTHERN COLORADO SHOULD LEAD TO ANOTHER
ACTIVE DAY...THOUGH MODELS ARE A LITTLE DIFFERENT ON TIMING AND
COVERAGE. NAM SOLN PVU FIELDS SHOW THE SHORT WAVE ENERGY DIPPING
INTO NORTHERN COLORADO EARLY IN THE DAY AS IT HAS A STRONGER SYSTEM
OVER THE NORTHERN ROCKIES...GFS NOT DEEPENING THE SYSTEM QUITE AS
MUCH AND KEEPS ANY SHORT WAVE FORCING JUST NORTH OF OUR BORDER. BY
AFTERNOON HOWEVER BOTH MODELS HAVE UPPER LEVEL DIVERGENCE OVER OUR
CENTRAL CWA AND WEAK SUBSIDENCE FILTERING INTO THE NORTH. THE
INHERITED POPS FOR SATURDAY COVERED THIS WELL AND MADE JUST A FEW
TWEAKS UPWARD WITH SLIGHT HIGHER CONFIDENCE. STILL CHANCE OF HEAVY
RAINFALL BUT STORM MOTIONS WILL BE ON THE INCREASE WHICH MAY ENHANCE
THE OUTFLOW WIND THREAT. TEMPERATURES SHOWING DIVERGING TREND IN
GUIDANCE WITH NAM LOWERING DUE TO BEING MORE ACTIVE. USED A BLEND
BUT GAVE MORE WEIGHT TO THE WARMER GUIDANCE ATTM.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI AUG 10 2012
AS THE FLOW BECOME MORE NORTHWESTERLY IN THE WAKE OF THE NORTHERN
SYSTEM DRIER AIR LOOKS TO FILTER INTO THE CWA SATURDAY NIGHT WITH
PWATS KNOCKING BACK TO UNDER .75 OVER ALL BUT THE FAR SOUTHWESTERN
PORTION OF THE CWA. THIS SHOULD ALLOW CONVECTION TO TAPER OFF
OVERNIGHT AND LEAD TO COOLER LOW TEMPERATURES. THIS DRY AIR WILL BE
IN PLACE FOR ONLY A SHORT TIME AS PWATS LOOK TO REBOUND BY LATE
SUNDAY AS THE UPPER HIGH CENTERS OVER THE SOUTHERN HIGH PLAINS. WITH
A LATE MOISTURE PUSH SOME STORMS MAY MAKE IT INTO THE VALLEYS BUT
FOR THE MOST PART THINK MOST STORM WILL BE MORE ROOTED TO THE
TERRAIN.
NOT MUCH CHANGE IN THE WEATHER PATTERN INTO THE EXTENDED PERIOD...WITH
SOUTHERLY MOIST FLOW CONTINUING INTO THE EARLY WORK WEEK WITH A
CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS EXPECTED EACH DAY
THROUGH WEDNESDAY. MODELS ARE HINTING AT THE RIDGE BUILDING TO OUR
WEST BY THURSDAY WHICH WOULD GENERATE SLIGHTLY DRIER CONDITIONS BY
LATE IN THE WEEK WITH A DECREASING THREAT OF SHOWERS AND
THUNDERSTORMS. EXPECT SEASONABLY WARM TEMPERATURES THROUGH THE
EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY NIGHT) ISSUED AT
300 AM MDT FRI AUG 10 2012
INCREASED MOISTURE COMBINED WITH A WEAK DISTURBANCE MOVING OVER
THE NORTHERN HALF OF THE FORECAST AREA WILL CONTINUE TO BRING
ISOLATED SHOWERS AND A STRAY THUNDERSTORM DURING THE REMAINDER OF
THE NIGHT. HOWEVER...EXPECT MVFR CONDITIONS THROUGH THIS MORNING.
DIURNAL HEATING COMBINED WITH INCREASING MOISTURE WILL BRING
ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS THIS
AFTERNOON WHICH WILL CONTINUE INTO THE EVENING HOURS. STORMS WILL
INITIALLY FORM OVER THE HIGHER TERRAIN RESULTING IN AREAS OF
MOUNTAIN OBSCURATION AND WIND GUSTS TO 45 MPH. STORMS WILL IMPACT
LOWER ELEVATIONS AFTER 20Z BRINGING ISOLATED MVFR CIGS AND VSBY TO
AIRPORTS ACROSS THE AREA...ESPECIALLY THOSE IN CLOSE PROXIMITY TO
MOUNTAINOUS TERRAIN. GUSTY OUTFLOW WINDS TO 50 MPH WILL ALSO BE A
MAIN CONCERN. SHOWERS AND EMBEDDED THUNDERSTORMS WILL DECREASE IN
AREAL COVERAGE AND INTENSITY AFTER SUNSET.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...15/MPM
LONG TERM...MPM
AVIATION...MPM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1015 AM EDT FRI AUG 10 2012
.SYNOPSIS...
LOW PRESSURE PASSING WEST OF NEW ENGLAND BRINGS A HIGH LIKELIHOOD OF
SHOWERS/THUNDERSTORMS TODAY THROUGH SATURDAY. SOME OF THE
THUNDERSTORMS MAY CONTAIN VERY HEAVY DOWNPOURS IN THE TROPICAL AIR
MASS. A FEW THUNDERSTORMS MAY ALSO PRODUCE STRONG WIND GUSTS. DRIER
AND LESS HUMID AIR RETURNS FOR LATE THIS WEEKEND INTO EARLY NEXT
WEEK. ANOTHER LOW PRESSURE WITH ASSOCIATED WARM AND COLD FRONTS
WILL IMPACT OUR REGION DURING THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...
WATCHING THE SITUATION CLOSELY. S NEW ENGLAND ENVELOPED IN A VERY
TROPICAL AIRMASS AT THE SFC WITH DWPTS IN THE LOW 70S. LATEST
SATELLITE EXHIBITS A FEW BREAKS IN THE MID-LVL CLOUDS...BUT
BENEATH WE ARE ALREADY SEEING N-S CLOUD STREETS INDICATIVE OF AN
UNSTABLE ENVIRONMENT.
SPC MESOANALYSIS HIGHLIGHTS INCREASING INSTABILITY OF 1-2K J/KG
ACROSS THE RGN...BUT THE BETTER 0-6 KM BULK SHEAR LAGS. WHILE
LIKELY SHOWERS AND THUNDERSTORMS WILL INCREASE IN AREAL CONVERAGE
WITH THE HEATING OF THE DAY...THE BETTER THREAT FOR SEVERE WX AND
HEAVY RAINS MAY NOT BE UNTIL LATER THIS AFTN INTO EVNG SUBSEQUENT
WITH A SHRTWV DISTURBANCE AND BETTER DEEP LYR SHEAR /30-40 KTS/
ROUNDING THRU THE BROADER TROF /PRESENTLY THE SHRTWV IS LOCATED
ACROSS THE CAROLINA RGN...LIFTING NEWD AND INVIGORATING ACTIVITY
OVER THE DELMARVA PENINSULA/. MID-LVL LAPSE RATES APPEAR MARGINAL
TODAY.
ITS IMPORTANT TO NOTE THAT ANY STORMS WITHIN THE VERY MOIST AND
TROPICAL AIRMASS WILL HAVE THE POSSIBILITY OF DROPPING AN INCH OF
RAIN IN 30 MINUTES OR LESS. PWATS ADVERTISED VIA SPC MESOANALYSIS
ALREADY THIS MORNING ARE AROUND 1.75 INCHES AND ANTICIPATING AN
INCREASE TOWARDS THE LATER HALF OF THE DAY ALONG AND AHEAD OF THE
ROUNDING SHRTWV DISTURBANCE. BUT THERE IS SOME MID-LVL DRYING
CONSEQUENTIAL FROM AIR FLOW ORIGINATING FROM THE W ATLANTIC RIDGE
/SEE THE 12Z UPR AIR ANALYSIS FROM CHATHAM AND NEW YORK VERSUS
ALBANY/. SUCH DRYING MAY IMPACT PWATS. STILL DO NOT BELIEVE THE
FLOOD THREAT WILL BE LESSENED.
SO SUMMARIZING...WITH THE SEVERE WX THREAT EXPECTING GUSTY WINDS
AND PSBL LARGE HAIL WITH A FEW OF THE STORMS. AS FOR FLOODING...
ANTICIPATE HEAVY RAINS WITHIN A SHORT PD OF TIME RESULTING IN
URBAN AND SMALL STREAM IMPACTS. STORMS LIKELY TO TRAIN ACROSS RGNS
RESULTING IN ROUNDS OF HEAVY RAINS.
OTHERWISE...SHORT-RANGE MDL SOLNS ARE NOT IMPRESSIVELY HANDLING
THE MORNING SITUATION WELL...THE 0Z CANADIAN/ECMWF ARE SEEMINGLY
DOING A GOOD JOB. THE MESO-RUC AND HRRR ARE SHOWING SOME ISSUES
WITH THE MORNING ACTIVITY. ALL FCST MDLS DO TREND AN AREA OF HEAVY
RAIN PROGRESSING NEWD FROM THE MID-ATLANTIC INTO S NEW ENGLAND
COLLOCATED WITH THE MAIN SHRTWV WITH IMPINGING S/SWLY LOW-MID LVL
LLJ TO THE REAR. THE EXACT LOCALE OF HEAVIEST RAINS IS STILL UNDER
SCRUTINY...BUT IT LOOKS LIKE HEAVY RAIN AND POTENTIAL FLOODING
WILL CONTINUE OVRNGT INTO THE MORNING PD.
TEMPS WILL BE A TAD COOLER /80 TO 85F/ THAN PREVIOUS DAYS AS CLOUD
COVER WILL BE THE MAIN FACTOR. HOWEVER DEWPOINTS ARE STILL WELL INTO
THE LOW 70 ALLOWING THE ATMOSPHERE TO BE QUITE MUGGY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
FRIDAY NIGHT...
EXPECT CONVECTION TO CONTINUE PAST SUNSET AS THERE IS SOME
ELEVATED INSTABILITY ACROSS THE AREA. STORM STRUCTURE HOWEVER WILL
BE MORE OF A CLUSTER WITH POSSIBLE BOWING SEGMENTS...DEEPENING ON
THE AMOUNT OF HEATING DURING THE DAY. WINDS WILL BACK TO THE
SOUTHWEST BY THE EVENING HOURS BLOCKING THE TROPICAL FEED FOR THE
WESTERN ZONES.
MAIN FOCUS FOR THE OVERNIGHT PERIOD IS THE WARM
FRONT THAT DEVELOPS ACROSS THE MID-ATLANTIC IN WHICH WILL MOVE
ACROSS SNE OVERNIGHT. EXPECT A LLJ TO DEVELOP BEHIND THE FRONT AND
THIS COMBINED WITH SAID FRONT AND HIGH PWATS BELIEVE A GOOD
SOAKING WILL TAKE PLACE. APPEARS THAT THE EASTERN PORTION OF THE
REGION WILL SEE THE HIGHEST AMOUNTS OF QPF AS PWATS ARE NEAR 2.5
INCHES. EXPECT PRECIP WITH PERHAPS EMBEDDED THUNDER WILL
CONTINUE WELL INTO OVERNIGHT PERIOD AND MOVE IN A MORE SOUTH TO
NORTH MANNER. IF ANY STORMS DEVELOP ALONG THE FRONT THEN THE
POTENTIAL FOR HEAVY DOWNPOURS AND FLASH FLOODING SHOULD BE
EXPECTED.
SATURDAY...
UPPER LEVEL LOW OVER THE GREAT LAKES WILL CONTINUE TO DRIFT
NORTHWARD INTO QUEBEC. THIS WILL PUSH A COLD FRONT ACROSS WESTERN NEW
ENGLAND. BELIEVE SHOWERS WILL CONTINUE INTO SATURDAY BUT EXACT
PLACEMENT IS A LITTLE UNCERTAIN. BELIEVE THE WEST HALF OF THE AREA
HAS THE BEST CHANCE SINCE THEY ARE CLOSER TO THE FRONT. THE
POTENTIAL FOR STRONG OR SEVERE STORMS IS LIMITED ONCE AGAIN TO THE
AMOUNT OF DAYTIME HEATING. BELIEVE STRONG STORMS AREA LIKELY WITH
GUSTY WINDS AND HEAVY RAIN BEING THE MAIN FOCUS. STORM STRUCTURE
SHOULD BE MORE MULTI-CELLULAR IN NATURE AND SHOULD EXPECT A LEAST
SOME STRONG STORMS. HOWEVER THE POTENTIAL OF SEVERE IS NOT OUT OF
THE QUESTION AS BULK SHEAR VALUES ARE 30KTS WITH MARGINAL LAPSE
RATES.
TEMPS WILL CREEP BACK INTO THE MID TO UPPER 80S AS 850MB TEMPS ARE
BETWEEN 16-18C . MUGGY CONDITIONS ARE EXPECTED AS DEWS ARE IN THE
LOW 70S. SATURDAY ALSO LOOKS A TAD ON THE BREEZY SIDE AS SOUTHERLY
WINDS LOOK TO GUST NEAR 20 MPH ALONG THE SOUTH COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
BIG PICTURE...
SERIES OF SHORT WAVE TROFS AMPLIFY WHAT LOOKS TO BE A MEAN LONG WAVE
TROF POSITION JUST W OF NEW ENGLAND. THE AMPLITUDE AND POSITIONING
OF THESE SHORT WAVE TROFS PROVIDE A FOCUS FOR CONVECTION AS WELL AS
OPEN THE DOOR TO TROPICAL MOISTURE. HAVE LEFT OVER SHOWERS AND TSTMS
SAT EVENING AND THEN ANOTHER BOUT WITH A WARM FRONT LATE TUE AND
COLD FRONT WED AFTERNOON AND EVE. STILL ANOTHER BOUT OF CONVECTION
AND TROPICAL MOISTURE POSSIBLE AT THE END OF THE WEEK.
SAT NIGHT...LEFT OVER SHOWERS AND EMBEDDED TSTMS MAY PERSIST MUCH OF
THE EVENING IN THE EAST. POTENTIAL REMAINS FOR SOME TSTMS TO PRODUCE
VERY HEAVY DOWNPOURS IN EASTERN SECTIONS WHERE PWATS REMAIN NEAR
OR ABOVE 2 INCHES.
SUN...THINK IT WILL BE DRY. TEMPS SHOULD REBOUND TO MID 80S WITH
MOSTLY SUNNY SKIES.
SUN NIGHT THRU MON NIGHT...LOOKS TO BE DRY. MON HIGH TEMP SHOULD
AGAIN BE IN THE MID 80S FOR MOST LOCATIONS...WHILE THE LOWER
DEWPOINTS ALLOW FOR COOLER OVERNIGHT TEMPS.
TUE/TUE NIGHT...WARMER AND MORE HUMID AIR BEGINS TO RETURN LATE TUE.
RISK OF SHOWERS/TSTMS WITH WARM FRONT LATE TUE INTO TUE NIGHT.
ALTHOUGH SOME DIFFERENCES IN TIMING AND PRECISE
CONFIGURATION...ECMWF AND GFS PAINT A SIMILAR PICTURE. HAVE CHANCE
POPS FOR LATE TUE AFTERNOON INTO TUE NIGHT.
WED...DIFFERENCES IN THE MODELS BUT ALL SUGGEST THAT A FAIRLY
PRONOUNCED SHORT WAVE TROF AND SURFACE COLD FRONT WILL MOVE THROUGH
WED AFTERNOON WITH AN AIR MASS OF WEAK TO MODERATE INSTABILITY.
HAVE CHANCE POPS IN THE GRIDS.
THU...LOOKS TO BE DRY WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE
NORMAL.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE CONFIDENCE. MVFR/IFR IN FOG AND STRATUS
DEVELOPMENT THROUGH THE MORNING HOURS. BECOMING MAINLY VFR MOST
LOCATIONS BETWEEN 13Z AND 15Z WITH AREAS OF MVFR/IFR CONDITIONS
IN TSRA/SHRA BECOMING MORE NUMEROUS DURING THE AFTERNOON AND
PERSISTING INTO SATURDAY.
KBOS TAF...MODERATE CONFIDENCE. IFR CIG SHOULD IMPROVE AROUND OR
SHORTLY AFT 13Z. SCT SHRA/TSRA LIKELY THIS AFTERNOON LASTING INTO
SATURDAY WITH FREQUENT PERIODS OF MVFR CIGS/VSBYS AND A FEW BRIEF
PERIODS OF IFR CIGS/VSBYS.
KBDL TAF...MODERATE CONFIDENCE. MVFR CIG IN STRATUS EXPECTED TO
IMPROVE TO VFR BETWEEN 13Z AND 14Z BUT INCREASING PERIODS OF MVFR
CIGS/VSBYS IN TSRA/SHRA LATE THIS MORNING AND AFTERNOON. SCT
TSRA/SHRA PERSTING INTO SATURDAY. CONFIDENCE ON TIMING LOW.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
SAT NIGHT...LOW TO MODERATE CONFIDENCE. WIDESPREAD AREAS OF MVFR
CIGS AND VSBYS IN SHOWERS AND EMBEDDED TSTMS. RAIN SHOULD END W TO E.
SUN THROUGH TUE MORNING...HIGH CONFIDENCE OF VFR.
TUE AFTERNOON/EVENING...MODERATE TO HIGH CONFIDENCE. MOSTLY VFR
EXCEPT FOR MVFR CIGS/VSBYS IN ANY SHOWERS/TSTMS.
&&
.MARINE...
MODERATE TO HIGH CONFIDENCE. EXPECT SOUTH TO SOUTHWEST WINDS AND
SEAS TO REMAIN BELOW SCA CRITERIA FOR TODAY. SHOWERS AND
THUNDERSTORMS LIKELY ON THE WATERS THIS AFTERNOON THROUGH TONIGHT.
A WARM FRONT WILL LIFT OVER THE WATERS DURING THE OVERNIGHT HOURS
AIDING IN SEAS TO DEVELOP OVER 5 FT. HAVE ISSUED A SCA ALONG THE
SOUTHERN WATERS WHERE 5FT SEAS ARE MOST LIKELY. LOW TO MODERATE
PROBABILITY OF PATCHY...POSSIBLY DENSE...FOG DEVELOPING ON THE
SOUTHERN WATERS TONIGHT.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
MODERATE TO HIGH CONFIDENCE.
SEAS OF 5 TO 6 FT LIKELY ACROSS EXPOSED SOUTH COAST WATERS THROUGH
MOST OF SUNDAY BEFORE GRADUALLY SUBSIDING SUN NIGHT. TSTMS SAT
EVENING MAY CONTAIN LOCALLY STRONG WIND GUSTS. QUIET WEATHER
EXPECTED MONDAY THROUGH AT LEAST MOST OF TUE.
&&
.HYDROLOGY...
STRONG CHANCE OF LOCALIZED STREET FLOODING TONIGHT AND SAT WITH
POSSIBILITY OF HIGHLY LOCALIZED FLASH FLOODING. AFTER COORDINATION
WITH ADJACENT OFFICES...DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH
FOR NOW. SEE A RISK OF A TROPICAL FEED AIDED BY A LOW LEVEL JET
IN AT LEAST A MARGINALLY UNSTABLE AIR MASS LATE TODAY THROUGH SATURDAY.
BEST DYNAMICS REMAIN WELL W AND N OF REGION...BUT COULD ENCOUNTER
SERIOUSLY EXCESSIVE RAINFALL IN ANY MESOSCALE BANDS THAT MAY SET
UP.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT
SATURDAY FOR ANZ235-237-255-256.
&&
$$
SYNOPSIS...DUNTEN/THOMPSON
NEAR TERM...SIPPRELL/DUNTEN/THOMPSON
SHORT TERM...DUNTEN
LONG TERM...THOMPSON
AVIATION...DUNTEN/THOMPSON
MARINE...DUNTEN/THOMPSON
HYDROLOGY...WFO STAFF
AREA FORECAST DISCUSSION
NWS MIAMI FL
1029 PM EDT SAT AUG 11 2012
.UPDATE...
LATEST FORECAST PACKAGE WAS UPDATED...MAINLY FOR INCREASED
RAINFALL CHANCES THROUGH THE OVERNIGHT HOURS. RAINFALL TOTALS HAVE
RANGED FROM A TENTH TO A HALF OF AN INCH ACROSS THE REGION WITH A
FEW AREAS RECORDING UP TO 2 TO 4 INCHES FROM THE ACTIVITY
TODAY...MAINLY OVER THE EAST COAST METRO AREAS. RECENTLY ANIMATED
WATER VAPOR LOOP SHOWED PLENTY OF MID/UPPER MOISTURE SPREADING
NORTH AND NORTHEAST BETWEEN AN UPPER LOW OVER THE WESTERN
CARIBBEAN AND THE UPPER RIDGE. THE EVENING SOUNDING REFLECTED THIS
WITH A PRECIPITABLE WATER VALUE AT 2.22 INCHES IN MIAMI. LATEST
RADAR LOOP SHOWED AREAS OF MAINLY LIGHT TO MODERATE SHOWERS
CONTINUING OVER PORTIONS OF THE AREA. THE LARGE AREA OF RAIN
PULLING NORTH FROM CUBA ACROSS THE FLORIDA STRAITS HAS MOSTLY
DIMINISHED...HOWEVER...WILL KEEP RAINFALL CHANCES UP THROUGH THE
OVERNIGHT PERIOD TO ACCOUNT FOR WHAT IS LEFT OF THIS SPREADING
NORTH INTO THE AREA. THE LATEST HRRR AND LOCALLY RUN WRF MODEL
REFLECTIVITIES ALSO SHOWED SCATTERED ACTIVITY CONTINUING THROUGH
THE NIGHT. WE REMOVED THE FOG WORDING IN THIS LATEST PACKAGE DUE
TO THE EXTENSIVE CLOUD COVERAGE. EXPECT THE WET CONDITIONS TO
CONTINUE SUNDAY WITH PRIMARILY SSW FLOW THROUGH THE LOW-LEVELS
CONTINUING. 85/AG
&&
.PREV DISCUSSION... /ISSUED 743 PM EDT SAT AUG 11 2012/
AVIATION...AFTERNOON CONVECTION BEGINNING TO DIMINISH BUT
EXTENSIVE MID TO HIGH CLOUD COVER WILL PERSIST WITH VICINITY OF
UPPER TROUGH AXIS. CONVECTION MOVING NORTH FROM CUBA BUT OVERALL
WILL WEAKEN AS IT APPROACHES S FL BUT STILL COULD BE SOME
TSRA ACTIVITY THROUGH 04Z SO LEFT VCTS FOR THE E CST TERMINALS.
ANOTHER ROUND OF CONVECTION IS LIKELY FOR SUNDAY AFT 17Z.
KOB
PREV DISCUSSION... /ISSUED 248 PM EDT SAT AUG 11 2012/
.ONE MORE WET DAY BEFORE DRIER CONDITIONS RETURN TO SOUTH
FLORIDA FOR NEXT WEEK....
SHORT TERM...
SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER THE EAST COAST
METRO AREAS THIS AFTERNOON ALONG THE EAST COAST SEA BREEZE.
THE SHOWERS AND THUNDERSTORMS SHOULD CONTINUE TO DEVELOP OVER
THE EAST COAST METRO AREAS THROUGH THE REST OF THE AFTERNOON...AS THE
EAST COAST SEA BREEZE WILL REMAIN NEARLY STATIONARY. SO WILL
CONTINUE THE SCATTERED TO NUMEROUS POPS OVER THE EAST COAST METRO
AREAS.
REST OF SOUTH FLORIDA SHOULD ALSO CONTINUE TO SEE SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS THROUGH THE AFTERNOON HOURS...AS
THE AREA IS STILL IN DEEP TROPICAL MOISTURE. SO WILL CONTINUE WITH
THE SCATTERED POPS OVER THE INTERIOR AND WEST COAST METRO AREAS.
THE SHOWERS AND THUNDERSTORMS SHOULD COME TO AN END THIS
EVENING AS THE HEATING OF THE DAY IS LOST. HOWEVER...THERE COULD
STILL BE A FEW SHOWERS OR THUNDERSTORMS OVER THE WEST COAST METRO
AREAS AND THE SOUTHERN AREAS OF SOUTH FLORIDA TONIGHT DUE TO THE
SOUTHERLY WIND FLOW. SO WILL KEEP SLIGHT CHANCE OF POPS OVER THE
WEST COAST AND SOUTHERN PORTIONS OF THE CWA FOR TONIGHT.
THE SOUTHERLY WIND FLOW WILL CONTINUE OVER SOUTH FLORIDA ON
SUNDAY...DUE TO A WEAK COLD FRONT OVER THE SOUTHEAST UNITED STATES
AND HIGH PRESSURE OVER THE BAHAMA ISLANDS. THIS WILL KEEP THE DEEP
TROPICAL MOISTURE IN PLACE OVER THE CWA. THE EAST AND WEST COAST
SEA BREEZES SHOULD ALSO DEVELOP AND PUSH INLAND ON SUNDAY.
THIS WILL LEAD TO SCATTERED POPS OVER THE AREA WITH EVEN LIKELY
POPS OVER THE LAKE OKEECHOBEE REGION.
THE WEAK FRONT WILL WASH OUT ON MONDAY ALLOWING FOR THE HIGH OVER
THE BAHAMA ISLANDS TO MOVE NORTH INTO THE NORTHWEST ATLANTIC
WATERS THROUGH TUESDAY. THIS WILL ALLOW FOR THE STEERING FLOW TO
BECOME MORE EASTERLY...AND ALLOW FOR DRIER AIR TO WORK INTO THE
AREA FROM THE EAST. THE SHORT RANGE MODELS ALSO CONTINUE TO SHOW
THE SAHARAN LAYER (DUST LAYER) EXPECTED TO MOVE INTO SOUTH FLORIDA
MONDAY NIGHT INTO TUESDAY. SO WILL CONTINUE TO SHOW A DOWNWARD TREND IN
POPS FOR EARLY NEXT WEEK.
LONG TERM...
THE HIGH OVER THE NORTHWEST ATLANTIC WATERS WILL REMAIN NEARLY
STATIONARY FOR THE MIDDLE TO THE END OF NEXT WEEK. THIS WILL KEEP THE
EASTERLY STEERING FLOW OVER THE CWA...AND ALLOW FOR THE TYPICAL
SUMMER TIME SHOWERS AND THUNDERSTORM ACTIVITY OVER SOUTH FLORIDA.
SO WILL CONTINUE THE SCATTERED POPS OVER THE CWA WITH THE HIGHEST
POPS OVER THE INTERIOR AREAS FOR MIDDLE TO END OF NEXT WEEK.
MARINE...
SOUTH TO SOUTHWEST WINDS WILL REMAIN BELOW 10 KNOTS FOR TONIGHT
INTO SUNDAY NIGHT BEFORE SWINGING TO A SOUTHEAST DIRECTION EARLY
NEXT WEEK. THIS WILL KEEP THE SEAS AT 2 FEET OR LESS OVER BOTH THE
ATLANTIC AND GULF WATERS OF SOUTH FLORIDA.
FIRE WEATHER...
THE RELATIVE HUMIDITIES WILL ALSO REMAIN ABOVE THE 35 PERCENT
CRITICAL VALUE OVER ALL OF SOUTH FLORIDA FOR SUNDAY INTO EARLY
NEXT WEEK. SO NO PROBLEMS ARE EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 90 76 90 / 50 40 30 30
FORT LAUDERDALE 77 90 78 90 / 50 40 20 30
MIAMI 77 91 78 91 / 50 40 20 30
NAPLES 75 89 76 90 / 30 40 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
739 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH
THE H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT
THE FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE
AHEAD OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS
AND THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE
POPS. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF
WEAK INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND
STRONG HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A
FEW SEVERE THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS
MAINLY EARLY TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS
LESS THAN ONE- QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE
CORRECT SINCE THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE
FORECAST AREA WHICH SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL
BE A THREAT OF VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER
VALUES AROUND 2 INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR
574 WHICH IS THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED
THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. LIFR/IFR CIGS ACROSS THE TAF
SITES WILL LIFT TO MVFR THROUGH 14Z. COULD EVEN SEE A FEW SHOWERS
EARLY THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z.
SOUTHWEST WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20
KNOTS. WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS
AFTERNOON INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...AN UNSETTLED WEATHER WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION
FRIDAY THROUGH SUNDAY...THEREBY HOLDING A GOOD CHANCE FOR CONVECTION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
601 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH
THE H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT
THE FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE
AHEAD OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS
AND THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE
POPS. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF
WEAK INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND
STRONG HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A
FEW SEVERE THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS
MAINLY EARLY TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS
LESS THAN ONE- QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE
CORRECT SINCE THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE
FORECAST AREA WHICH SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL
BE A THREAT OF VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER
VALUES AROUND 2 INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR
574 WHICH IS THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED
THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. SOUTH WIND 5-10 KT THIS
MORNING WILL FAVOR STRATUS CLOUDS RATHER THAN FOG. GUIDANCE HAVE
COME INTO AGREEMENT WITH LIFR/IFR CIGS ACROSS THE TAF SITES THROUGH
14-15Z. SO CONFIDENCE IS HIGH. COULD EVEN SEE A FEW SHOWERS EARLY
THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z. SOUTHWEST
WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20 KNOTS.
WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS AFTERNOON
INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...AN UNSETTLED WEATHER WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION
FRIDAY THROUGH SUNDAY...THEREBY HOLDING A GOOD CHANCE FOR CONVECTION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
559 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH THE
H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT THE
FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE AHEAD
OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS AND
THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE POPS.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF WEAK
INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND STRONG
HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A FEW SEVERE
THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS MAINLY EARLY
TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS LESS THAN
ONE-QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE CORRECT SINCE
THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE FORECAST AREA WHICH
SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL BE A THREAT OF
VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER VALUES AROUND 2
INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR 574 WHICH IS
THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. SOUTH WIND 5-10 KT THIS
MORNING WILL FAVOR STRATUS CLOUDS RATHER THAN DENSE FOG. GUIDANCE
HAVE COME INTO AGREEMENT WITH LIFR/IFR CIGS ACROSS THE TAF SITES
THROUGH 14-15Z. SO CONFIDENCE IS HIGH. COULD EVEN SEE A FEW SHOWERS
EARLY THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z.
SOUTHWEST WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20
KNOTS. WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS
AFTERNOON INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...A COLD FRONT WILL MOVE THROUGH THE
REGION SATURDAY THROUGH SUNDAY. AN UNSETTLED WEATHER WILL PERSIST
THROUGH EARLY SUNDAY...WITH PERIODS OF SHOWERS AND THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
253 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH THE FORECAST AREA FROM THE
NORTHWEST THROUGH TONIGHT. THE FRONT WILL BECOME DIFFUSE SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MOISTURE WILL BE HIGH AHEAD OF THE SLOW MOVING COLD FRONT TODAY.
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY ASSOCIATED WITH THE
H85 JET. THE RAP AND NAM INDICATE THE JET WILL MAINLY AFFECT THE
FORECAST AREA EARLY TODAY. HOWEVER...CONTINUED HIGH MOISTURE AHEAD
OF THE FRONT AND DIURNAL HEATING SUPPORTS ADDITIONAL SHOWERS AND
THUNDERSTORMS LATER TODAY. LEANED TOWARD THE HIGHER GUIDANCE POPS.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM/S FORECAST OF WEAK
INSTABILITY APPEARS REASONABLE. IF SIGNIFICANT BREAKS AND STRONG
HEATING DOES OCCUR THEN THERE WILL BE ENOUGH SHEAR FOR A FEW SEVERE
THUNDERSTORMS. THE NAM SHOWS H85 WINDS NEAR 30 KNOTS MAINLY EARLY
TODAY. BOTH THE NAM AND GFS SHOW RAINFALL AMOUNTS LESS THAN
ONE-QUARTER OF AN INCH AND THESE GENERAL VALUES MAY BE CORRECT SINCE
THE H85 JET MAXIMUM SHOULD BE NORTHEAST OF THE FORECAST AREA WHICH
SHOULD LIMIT CONVERGENCE. HOWEVER...THERE WILL BE A THREAT OF
VERY HEAVY RAIN BECAUSE OF PRECIPITABLE WATER VALUES AROUND 2
INCHES. ALSO...EXPECT 1000-500 MB THICKNESSES NEAR 574 WHICH IS
THE PREFERRED VALUE FOR HEAVY RAIN IN AUGUST. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MOISTURE AND CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT
SUPPORTS SHOWERS AND THUNDERSTORMS TONIGHT. HOWEVER...INSTABILITY
SHOULD BE LIMITED BY PREVIOUS CONVECTION AND DIURNAL COOLING.
FORECASTED POPS OF LIKELY EARLY AND CHANCE LATE. THE NAM AND GFS
SHOW THE FRONT LINGERING NEAR THE FORECAST AREA SATURDAY AND
SATURDAY NIGHT BUT DEEPER MOISTURE APPEARS TO SHIFT A LITTLE EAST
OF THE FORECAST AREA SATURDAY. THE NAM AND GFS MOS SUPPORT CHANCE
POPS. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST
THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS SHOWS RIDGING TO THE SOUTH WITH LEE-SIDE TROUGHING IN THE
FORECAST AREA DURING MUCH OF THE EXTENDED PERIOD. THE PATTERN
SUPPORTS MAINLY DIURNAL SCATTERED THUNDERSTORMS. THE GFS ENSEMBLE
MEANS SUPPORT SLIGHT CHANCE OF CHANCE POPS. EXPECT TEMPERATURES NEAR
CLIMATOLOGY WITH LOWS IN THE LOWER 70S AND HIGHS IN THE LOWERS 90S.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
LOW LEVEL JET AFFECTING THE AREA TODAY. SOUTH WIND 5-10 KT THIS
MORNING WILL FAVOR STRATUS CLOUDS RATHER THAN FOG. GUIDANCE HAVE
COME INTO AGREEMENT WITH LIFR/IFR CIGS ACROSS THE TAF SITES THROUGH
14-15Z. SO CONFIDENCE IS HIGH. COULD EVEN SEE A FEW SHOWERS EARLY
THIS MORNING. EXPECT IMPROVING CONDITIONS BY 15Z-16Z. SOUTHWEST
WINDS INCREASING TO 10-15KT BY MIDDAY WITH GUSTS NEAR 20 KNOTS.
WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AGAIN THIS AFTERNOON
INTO TONIGHT.
EXTENDED AVIATION OUTLOOK...AN UNSETTLED WEATHER WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION
FRIDAY THROUGH SUNDAY...THEREBY HOLDING A GOOD CHANCE FOR CONVECTION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
305 AM CDT FRI AUG 10 2012
.DISCUSSION...
ISSUED 305 AM CDT FRI AUG 10 2012
SHORT TERM...TODAY THROUGH SUNDAY
UNSEASONABLY DEEP UPPER-LEVEL LOW WILL CONTINUE TO SPIN OVER THE
GREAT LAKES TODAY. POCKET OF VERY COLD AIR ALOFT CHARACTERIZED BY
500MB TEMPS OF -14 TO -16C WILL PRODUCE ENOUGH DAYTIME INSTABILITY
TO TRIGGER PLENTY OF DIURNAL CLOUDINESS AND EVEN A FEW ISOLATED
SHOWERS ALONG THE ILLINOIS/INDIANA BORDER. TIGHTENING PRESSURE
GRADIENT BETWEEN DEVELOPING SURFACE LOW OVER THE OHIO RIVER VALLEY
AND APPROACHING HIGH ACROSS THE PLAINS WILL CREATE GUSTY NORTHERLY
WINDS...WITH FORECAST SOUNDINGS SUGGESTING GUSTS TO AROUND 25 MPH.
THANKS TO THE BRISK NORTHERLY FLOW AND PARTIAL CLOUD COVER...HIGH
TEMPS WILL REMAIN BELOW NORMAL FOR THIS TIME OF YEAR IN THE MIDDLE
TO UPPER 70S.
SKIES WILL CLEAR AND WINDS WILL DIMINISH TONIGHT...ALLOWING
EXCELLENT RADIATIONAL COOLING CONDITIONS TO DEVELOP. OVERNIGHT LOW
TEMPERATURES WILL GENERALLY DROP INTO THE MIDDLE TO UPPER
50S...WITH A FEW FAVORED LOCATIONS DIPPING INTO THE LOWER 50S.
PLENTY OF SUNSHINE AND CONTINUED COOL WEATHER WILL CONTINUE INTO
SATURDAY...WITH AIRMASS MODIFICATION PRODUCING HIGHS AROUND 80 DEGREES.
MODELS CONTINUE TO ADVERTISE NEXT SHORT-WAVE APPROACHING FROM THE
NORTHWEST BY LATE SUNDAY. GIVEN DRY AIRMASS AND SLIGHTLY SLOWER
ARRIVAL OF WAVE...WILL KEEP PRECIP CHANCES OUT OF THE FORECAST
THROUGH THE DAY SUNDAY. STRONGER SYNOPTIC LIFT WILL ARRIVE WITH
THE WAVE BY SUNDAY NIGHT...SO WILL INTRODUCE A CHANCE FOR
SHOWERS/STORMS AT THAT TIME.
LONG TERM...MONDAY THROUGH THURSDAY
SCATTERED SHOWERS/STORMS WILL LINGER INTO MONDAY...BEFORE WAVE
PUSHES EAST OF THE REGION AND DRY WEATHER RETURNS MONDAY NIGHT AND
TUESDAY. UPPER HEIGHTS WILL BEGIN TO RISE IN THE WAKE OF THE
SYSTEM...ALTHOUGH LATEST MODEL RUNS DO NOT BUILD RIDGING INTO THE
MIDWEST QUITE AS AGGRESSIVELY AS PREVIOUS RUNS. WILL SEE A
DEFINITE WARMING TREND NEXT WEEK...HOWEVER HAVE TEMPERED THE
READINGS A BIT...WITH HIGHS ONLY BACK INTO THE UPPER 80S BY
WEDNESDAY. MODELS STILL SHOWING SOME TIMING DISCREPANCIES WITH
NEXT APPROACHING WAVE...BUT CONSENSUS BRINGS IT INTO THE AREA
WEDNESDAY NIGHT/THURSDAY. GIVEN PROJECTED STRENGTH OF FEATURE AND
EXPECTED SUPPLY OF AVAILABLE MOISTURE...THINK CHANCE POPS FOR
SHOWERS/STORMS ARE WARRANTED AT THAT TIME.
BARNES
&&
.AVIATION...
ISSUED 1145 PM CDT THU AUG 9 2012
MAIN CONCERN IS WITH TIMING FOR POTENTIAL MVFR/IFR CEILINGS. LARGE
UPPER LOW CURRENTLY CENTERED JUST NORTH OF KORD AND WILL MOVE INTO
NORTHERN INDIANA BEFORE SUNRISE. SATELLITE AND SURFACE OBS SHOWING
AN INCREASE IN MVFR CONDITIONS NEAR/NORTH OF THIS LOW...AND THIS
WILL BE SWINGING SOUTHWARD ACROSS ILLINOIS OVER THE NEXT FEW
HOURS. LATEST GUIDANCE FROM THE RAP MODEL SUGGESTING THESE LOWER
CEILINGS WILL PUSH INTO CENTRAL ILLINOIS FROM THE NORTHEAST... SO
WILL BEGIN WITH THE LOWER CEILINGS NEAR KBMI/KCMI AT THE START OF
THE TAF PERIOD WITH SOME TEMPO VFR CONDITIONS THROUGH ABOUT 08Z.
THE REMAINDER OF THE TAFS SHOULD SEE CLOUDS LOWERING TO 1000-2000
FEET BEGINNING AROUND 08Z...ALTHOUGH SOME BREAKS IN THE CLOUDS
WILL STILL BE POSSIBLE. A STEADIER BREAK-UP OF THE CLOUDS IS
EXPECTED TO DEVELOP SHORTLY AFTER SUNRISE...AS THE LOW PULLS EAST
OF THE REGION. VFR CONDITIONS SHOULD PREVAIL BY LATE MORNING.
NORTH WINDS SHOULD PICK UP SOME ON FRIDAY...AS CLOUDS DECREASE AND
ALLOW FOR SOME MIXING TO TAKE PLACE FROM AROUND 5000 FEET. MAY SEE
SOME GUSTS OF 15-20 KNOTS IN A FEW AREAS DURING THE MIDDAY AND
AFTERNOON HOURS. WINDS WILL DIMINISH TOWARD SUNSET.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1146 PM CDT THU AUG 9 2012
.DISCUSSION...
ISSUED 833 PM CDT THU AUG 9 2012
STRONGEST CONVECTION WHICH PRODUCED SEVERE WEATHER REPORTS FROM
BLOOMINGTON TO PARIS EASTWARD HAS PUSHED INTO INDIANA...BUT SOME
SHOWERS AND THUNDERSTORMS LINGER OVER CENTRAL AND SOUTHEAST
ILLINOIS. MANY OF THESE WERE ALONG AN OUTFLOW BOUNDARY...WHICH
WAS IN AN ARCH FROM FULTON COUNTY TO EFFINGHAM...THEN NORTHEAST TO
NEAR DANVILLE. MESOANALYSIS SHOWING SOME AREAS OF CAPES ABOVE 1000
J/KG LINGERING OVER CENTRAL AND SOUTHEAST ILLINOIS. HOWEVER... THE
WINDOW OF OPPORTUNITY FOR ADDITIONAL SEVERE WEATHER IS
NARROWING...AS ANOTHER BOUNDARY DROPS SOUTH FROM NORTHERN ILLINOIS
AND LOWERS TEMPERATURES INTO THE 60S. THE CLEARING THAT HAS BEEN
OCCURRING OVER THE CWA WILL FILL BACK IN AGAIN...AS A LARGE UPPER
LOW DROPS SOUTH OUT OF WISCONSIN.
HAVE SENT SOME ZONE/GRID UPDATES FOR THE LATEST CONVECTIVE
TRENDS...AND SOME MINOR ADJUSTMENTS TO THE HOURLY TEMPERATURES.
OVERALL LOWS FOR TONIGHT STILL LOOK GOOD.
GEELHART
&&
.AVIATION...
ISSUED 1145 PM CDT THU AUG 9 2012
MAIN CONCERN IS WITH TIMING FOR POTENTIAL MVFR/IFR CEILINGS. LARGE
UPPER LOW CURRENTLY CENTERED JUST NORTH OF KORD AND WILL MOVE INTO
NORTHERN INDIANA BEFORE SUNRISE. SATELLITE AND SURFACE OBS SHOWING
AN INCREASE IN MVFR CONDITIONS NEAR/NORTH OF THIS LOW...AND THIS
WILL BE SWINGING SOUTHWARD ACROSS ILLINOIS OVER THE NEXT FEW
HOURS. LATEST GUIDANCE FROM THE RAP MODEL SUGGESTING THESE LOWER
CEILINGS WILL PUSH INTO CENTRAL ILLINOIS FROM THE NORTHEAST... SO
WILL BEGIN WITH THE LOWER CEILINGS NEAR KBMI/KCMI AT THE START OF
THE TAF PERIOD WITH SOME TEMPO VFR CONDITIONS THROUGH ABOUT 08Z.
THE REMAINDER OF THE TAFS SHOULD SEE CLOUDS LOWERING TO 1000-2000
FEET BEGINNING AROUND 08Z...ALTHOUGH SOME BREAKS IN THE CLOUDS
WILL STILL BE POSSIBLE. A STEADIER BREAK-UP OF THE CLOUDS IS
EXPECTED TO DEVELOP SHORTLY AFTER SUNRISE...AS THE LOW PULLS EAST
OF THE REGION. VFR CONDITIONS SHOULD PREVAIL BY LATE MORNING.
NORTH WINDS SHOULD PICK UP SOME ON FRIDAY...AS CLOUDS DECREASE AND
ALLOW FOR SOME MIXING TO TAKE PLACE FROM AROUND 5000 FEET. MAY SEE
SOME GUSTS OF 15-20 KNOTS IN A FEW AREAS DURING THE MIDDAY AND
AFTERNOON HOURS. WINDS WILL DIMINISH TOWARD SUNSET.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT THU AUG 9 2012
INITIAL CONCERN IS WITH CHANCES FOR SEVERE STORMS LATE THIS
AFTERNOON AND THIS EVENING. NEXT HIGHLIGHTS WILL BE THE COOLER
AIRMASS FOR THE WEEKEND FOLLOWED BY A COUPLE OF CHANCES FOR RAIN
SUNDAY NIGHT INTO MONDAY AND WEDNESDAY NIGHT INTO THURSDAY.
OUR CURRENT WEATHER IS BEING DRIVEN BY WEAK CYCLOGENESIS THAT
APPEARS TO BE CENTERED JUST NORTH OF PEORIA...ALONG A SURFACE
TROUGH EXTENDING NORTH FROM LOW PRESSURE IN SOUTHERN IL. THAT LOW
WAS LOCATED ALONG A STATIONARY FRONT THAT EXTENDED ROUGHLY ALONG
THE OHIO RIVER VALLEY AND SOUTHWEST INTO OKLAHOMA. ALOFT...A WELL
DEVELOPED TROUGH ACROSS THE GREAT LAKES WAS BEING REINFORCED BY A
CLOSED LOW AT 500MB DROPPING SOUTH FROM NW WISCONSIN TOWARD
NORTHERN IL. A NORTH-SOUTH ORIENTED 115 KT 300MB JET MAX WAS
POSITIONED JUST WEST OF THE 500MB LOW...AND ROTATING SOUTH AND
EAST AROUND THE UPPER TROUGH.
MODELS ARE HAVING A DIFFICULT TIME CATCHING UP WITH THE WEAK
SURFACE PRESSURE PATTERN THAT IS BEGIN EASILY ALTERED BY STORM
OUTFLOWS/GUST FRONTS/COLD POOLS. IN GENERAL...WE DECIDED TO LEAN
MORE CLOSELY WITH THE 00Z ECMWF.
SHORT TERM...TONIGHT THROUGH SUNDAY.
SOME FILTERED SUNSHINE HAS HELPED THE AIRMASS DESTABILIZE EARLY
THIS AFTERNOON. SFC BASED CAPES HAVE CLIMBED TO AROUND 1500
J/KG WITH MU CAPES OF 2000 J/KG JUST EAST OF THE SFC CYCLOGENESIS
NEAR PEORIA. EFFECTIVE SHEAR HAS INCREASED TO AROUND 25 TO 30KT.
THAT HAS HELPED A FEW STORMS DEVELOP UNDER THE LOW NW OF PEORIA.
VERTICAL DEVELOPMENT OF THOSE STORMS HAVE REMAINED IN CHECK SO
FAR...WITH STORM TOPS AROUND 30K FT. ENOUGH OF A DRY LAYER BELOW
700MB WILL ALLOW FOR SOME ENHANCED DOWNBURST POTENTIAL WITH ANY
STRONGER STORMS...AND THE FREEZING LEVEL DOWN AROUND 12K FT WILL
BE MORE FAVORABLE FOR HAIL PRODUCTION.
WE WILL MONITOR STORM PROGRESS AND DEVELOPMENT CLOSELY FOR AN
INTENSIFICATION...BUT THE BETTER CHANCES FOR SEVERE STORMS APPEARS
TO BE IN OUR EAST AND SOUTHEAST COUNTIES CLOSER TO THE STATIONARY
FRONT AND SURFACE LOW IN SOUTHERN ILLINOIS. THE DY1 SLIGHT RISK
WAS EXPANDED WESTWARD AT 17Z TO INCLUDE ALL BUT OUR FAR W-NW
COUNTIES...SO WILL NOT RULE OUT SEVERE CHANCES AS FAR WEST AS THE
ILLINOIS RIVER.
WE WILL KEEP HIGH CHANCE POPS FOR EVERYWHERE THE REST OF THE
AFTERNOON AND ACROSS THE EASTERN HALF THIS EVENING...AS THE WEAK
SURFACE LOW NEAR PEORIA SLIDES EAST-SOUTHEAST TOWARD INDIANA.
AFTER MIDNIGHT...ANY LINGERING SHOWERS/STORMS SHOULD BE CONFINED
TO OUR COUNTIES EAST OF I-57.
THE COLD POOL ALOFT WILL BE REINFORCED BY THE PASSAGE OF THE CLOSED
LOW ACROSS NE ILLINOIS LATER TONIGHT AND FRIDAY. THE UPPER LOW IS
THEN EXPECTED TO ROTATE BACK NORTHEAST INTO THE CENTRAL GREAT
LAKES AND LINGER THERE SATURDAY BEFORE LIFTING NORTHEAST INTO
ONTARIO SAT NIGHT. THAT SCENARIO WILL PUT CENTRAL ILLINOIS IN A
COOL NORTHWEST FLOW ALOFT...WITH WEAK SURFACE HIGH PRESSURE
HELPING TO PROVIDE DRY CONDITIONS FRIDAY INTO SUNDAY.
BELOW NORMAL HIGHS ARE EXPECTED FRIDAY THROUGH SUNDAY. FRIDAY WILL
BE THE COLDEST DAY WITH HIGHS ONLY IN THE UPPER 70S...THEN HIGHS
WILL CLIMB INTO THE LOWER 80S FOR SAT AND SUN.
THE ECMWF AND GFS BOTH SHOW A WEAK SFC LOW EJECTING FROM THE
PLAINS ACROSS MISSOURI ON SUNDAY...POSSIBLY BRINGING A CHANCE OF
RAIN WEST OF I-55 SUNDAY AFTERNOON. WE DECIDED TO INTRODUCE SLIGHT
CHANCE POPS SUNDAY...THEN INCREASE TO CHANCE POPS SUNDAY NIGHT AS
THE LOW REACHES WESTERN IL AND THE 500MB TROUGH DROPS SOUTHEAST
INTO NORTHERN IL. A FEW STORMS MAY DEVELOP SUNDAY NIGHT DUE TO THE
STEEP LAPSE RATES IN THE COLD POOL ALOFT.
LONG TERM...MONDAY THROUGH THURSDAY
WE HELD ONTO SLIGHT CHANCE POPS ON MONDAY BEFORE THE SURFACE
TROUGH DISSIPATES AND THE UPPER TROUGH SLIDES EAST OF IL. A
REINFORCING PUSH OF COLDER AIR ALOFT WILL HELP TO KEEP LOWS
SLIGHTLY BELOW NORMAL AGAIN ON MONDAY...IN THE LOW TO MID 80S.
WEAK SURFACE RIDGING SHOULD GIVE US BETTER CHANCES OF REMAINING
DRY AGAIN MONDAY NIGHT THROUGH WEDNESDAY. HOWEVER...THE NORTHWEST
FLOW ALOFT ALWAYS LEAVES THE DOOR OPEN FOR AN UNRESOLVED SHORTWAVE
TO SLIP INTO THE AREA AND KICK OFF A FEW SHOWERS/STORMS. FOR
NOW...WE KEPT THE FORECAST DRY UNTIL A MORE PROMINENT WEATHER
DISTURBANCE IS FORECAST TO ARRIVE WED NIGHT AND THURSDAY.
SOME WEAK SOUTHERLY FLOW DEVELOPING ON WED SHOULD HELP HIGH TEMPS
RETURN TO THE UPPER 80S BOTH WED AND THURS.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1221 PM CDT FRI AUG 10 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
MAIN FOCUS TODAY WILL BE ON CLOUD COVER AND TEMPERATURES FOR THE
NEAR TERM. CWA TO REMAIN BENEATH CYCLONIC FLOW ALOFT...WITH WEAK CAA
EXPECTED THROUGHOUT THE DAY. SOME LOW LEVEL MOISTURE RESULTING IN AN
AREA OF LOW STRATUS CONTINUES TO DEVELOP OFF TO THE NORTHEAST OF THE
CWA...WITH MODEL PROGGING THIS AREA OF STRATUS TO CONTINUE TO
SPREAD/ADVECT INTO THE NORTHERN/EASTERN HALF OF THE CWA THROUGH
SUNRISE. HRRR MODEL AND GOES-R WRF FORECAST BOTH HANDLING THE
DEVELOPMENT OF THIS STRATUS WELL AND HAVE TAILORED SKY GRIDS TOWARD
THE MODEL/SATELLITE PRODUCT TRENDS. EXPECT STRATUS TO LIFT/BREAK UP
TOWARD MID/LATE MORNING ACROSS THE AREA...WITH RESULTANT MID LEVEL
CU FIELD POSSIBLE. OTHERWISE MUCH DRIER TO MOVE INTO THE CWA WITH
DEWPOINTS EXPECTED TO CONTINUE TO DROP TO AROUND 50 POSSIBLY EVEN
INTO THE 40S WITH DRIER AIR MIXING DOWN AND ADVECTING INTO THE CWA
IN NORTHERLY FLOW. WITH THE CAA...EXPECT TEMPS TO BE A FEW DEGREES
COOLER THAN YESTERDAY WITH HIGHS MAINLY IN THE UPPER 70S TO AROUND
80.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
CANADIAN HIGH PRESSURE MOVING INTO THE NORTHERN PLAINS EARLY THIS
MORNING WITH TEMPERATURES DIPPING INTO THE LOW TO MID 40S OVER THE
SOUTHEAST QUADRANT. THIS SYSTEM WILL SETTLE SOUTH TODAY AND BE
STRETCHED OVER MUCH OF THE CENTRAL AND NORTHERN PLAINS TONIGHT.
WHILE SOME MODIFICATION OF TEMPERATURES IS EXPECTED...SHOULD HAVE
OVERNIGHT LOWS TONIGHT TOUCHING THE MID 40S AT A FEW LOCATIONS
ACROSS THE NORTH AND INTO THE LOW TO MID 50S ELSEWHERE. THE CLOSED
UPPER LOW THAT AFFECTED THE AREA ON THURSDAY WILL BE SHIFTING SLOWLY
NORTHEAST ACROSS THE CENTRAL GREAT LAKES THROUGH MID DAY SATURDAY
BEFORE GAINING STEAM SATURDAY NIGHT AS ANOTHER CLOSED UPPER LOW
MOVES INTO CENTRAL CANADA. THIS WILL ALLOW A TRANSITION TO A MORE
PROGRESSIVE NORTHWEST FLOW THAT WILL PERSIST THROUGH MUCH OF THE
EXTENDED.
A FAIRLY SIGNIFICANT SYSTEM WILL ARRIVE OVER THE PACIFIC NW LATE
TODAY THEN MOVE ACROSS THE ROCKIES AND PRODUCE LEE SIDE CYCLOGENESIS
INTO SATURDAY. SATURDAY WILL BE ANOTHER PLEASANT DAY AND EXPECT
TEMPERATURES TO BE NEAR THE HIGH END OF GUIDANCE WITH DRY SFC AIR
HEATING UP EFFICIENTLY. MID LEVEL THETA-E ADVECTION WILL COMMENCE
SATURDAY NIGHT WITH THE INITIAL WAVE BEING SPENT ON MID LEVEL
SATURATION. GULF MOISTURE WILL BREAK FREE AND BEGIN TO STREAM
NORTHWARD SATURDAY NIGHT AS WELL WITH THE MOISTURE ADVECTION
ARRIVING LATE AIDED BY AN INCREASING LOW LEVEL JET APPROACHING 40
KTS. THE COMBINATION OF THE MULTI LEVEL KINEMATICS AND
THERMODYNAMICS WILL RESULT IN A DEEPLY FORCED SYSTEM WITH SHOWERS
AND THUNDERSTORMS ARRIVING OVER THE WEST AFTER MIDNIGHT. ADDITIONAL
CHANCES WILL CONTINUE SUNDAY AND SUNDAY NIGHT WITH AS THE SECOND
SEGMENT OF THE UPPER LEVEL SYSTEM ARRIVES ALONG WITH THE SFC LOW
REFLECTION. GENERAL AGREEMENT DEVELOPING THAT THE SFC LOW WILL SHIFT
EAST ACROSS SOUTHERN IA AND WOULD ALLOW A PORTION OF THE WARM SECTOR
TO LIFT INTO THE STATE. HIGH VARIABILITY POSSIBLE WITH HIGH
TEMPERATURES ON SUNDAY WHERE HIGHS COULD STRUGGLE IN THE 60S UNDER
INCREASING CLOUDS AND MORE PROLONGED PRECIPITATION WHILE RISING WELL
INTO THE 80S SOUTH WHERE SOME SUN COULD BE POSSIBLE. THIS COULD LEAD
TO AN AREA OF SFC BASED THUNDERSTORMS AND AN AREA WITH SEVERE
POTENTIAL. PRECIPITATION CHANCES CONTINUE OVER MAINLY THE EAST
SUNDAY EVENING BEFORE ENDING.
THE REMAINDER OF THE EXTENDED IS HIGHLIGHTED BY SEVERAL IMPULSES
RIPPLING THROUGH THE NW FLOW WHILE A DEEP UPPER LEVEL LOW DROPS INTO
ALBERTA AND MANITOBA BY MID WEEK. OVERALL TIMING BECOMES DIFFICULT
UNDER THESE SITUATIONS BUT GENERAL CONSENSUS IS A WEAK WAVE ARRIVING
TUE NIGHT INTO WED WITH A MORE SIGNIFICANT SYSTEM IMPACTING THE AREA
TOWARD THE END OF THE PERIOD AS ENERGY ASSOCIATED THE SOUTHERN
CANADA SYSTEM ARRIVES.
&&
.AVIATION...10/18Z
BAND OF MVFR AND IFR STRATUS WHICH AFFECTED SITES EARLY THIS MORNING
WILL CONTINUE TO DIMINISH...LIFTING TO VFR CEILINGS. WINDS WILL BE
GUSTY IN THE AFTERNOON BUT WILL DIMINISH NEAR 00Z. HIGH PRESSURE
WILL PUSH INTO REGION...WITH WINDS REMAINING PRIMARILY FROM THE
NORTH...AND CEILINGS WILL REMAIN VFR THROUGH REMAINDER OF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...DONAVON
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
620 AM CDT FRI AUG 10 2012
.SHORT TERM /TONIGHT/...
MAIN FOCUS TODAY WILL BE ON CLOUD COVER AND TEMPERATURES FOR THE
NEAR TERM. CWA TO REMAIN BENEATH CYCLONIC FLOW ALOFT...WITH WEAK CAA
EXPECTED THROUGHOUT THE DAY. SOME LOW LEVEL MOISTURE RESULTING IN AN
AREA OF LOW STRATUS CONTINUES TO DEVELOP OFF TO THE NORTHEAST OF THE
CWA...WITH MODEL PROGGING THIS AREA OF STRATUS TO CONTINUE TO
SPREAD/ADVECT INTO THE NORTHERN/EASTERN HALF OF THE CWA THROUGH
SUNRISE. HRRR MODEL AND GOES-R WRF FORECAST BOTH HANDLING THE
DEVELOPMENT OF THIS STRATUS WELL AND HAVE TAILORED SKY GRIDS TOWARD
THE MODEL/SATELLITE PRODUCT TRENDS. EXPECT STRATUS TO LIFT/BREAK UP
TOWARD MID/LATE MORNING ACROSS THE AREA...WITH RESULTANT MID LEVEL
CU FIELD POSSIBLE. OTHERWISE MUCH DRIER TO MOVE INTO THE CWA WITH
DEWPOINTS EXPECTED TO CONTINUE TO DROP TO AROUND 50 POSSIBLY EVEN
INTO THE 40S WITH DRIER AIR MIXING DOWN AND ADVECTING INTO THE CWA
IN NORTHERLY FLOW. WITH THE CAA...EXPECT TEMPS TO BE A FEW DEGREES
COOLER THAN YESTERDAY WITH HIGHS MAINLY IN THE UPPER 70S TO AROUND
80.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
CANADIAN HIGH PRESSURE MOVING INTO THE NORTHERN PLAINS EARLY THIS
MORNING WITH TEMPERATURES DIPPING INTO THE LOW TO MID 40S OVER THE
SOUTHEAST QUADRANT. THIS SYSTEM WILL SETTLE SOUTH TODAY AND BE
STRETCHED OVER MUCH OF THE CENTRAL AND NORTHERN PLAINS TONIGHT.
WHILE SOME MODIFICATION OF TEMPERATURES IS EXPECTED...SHOULD HAVE
OVERNIGHT LOWS TONIGHT TOUCHING THE MID 40S AT A FEW LOCATIONS
ACROSS THE NORTH AND INTO THE LOW TO MID 50S ELSEWHERE. THE CLOSED
UPPER LOW THAT AFFECTED THE AREA ON THURSDAY WILL BE SHIFTING SLOWLY
NORTHEAST ACROSS THE CENTRAL GREAT LAKES THROUGH MID DAY SATURDAY
BEFORE GAINING STEAM SATURDAY NIGHT AS ANOTHER CLOSED UPPER LOW
MOVES INTO CENTRAL CANADA. THIS WILL ALLOW A TRANSITION TO A MORE
PROGRESSIVE NORTHWEST FLOW THAT WILL PERSIST THROUGH MUCH OF THE
EXTENDED.
A FAIRLY SIGNIFICANT SYSTEM WILL ARRIVE OVER THE PACIFIC NW LATE
TODAY THEN MOVE ACROSS THE ROCKIES AND PRODUCE LEE SIDE CYCLOGENESIS
INTO SATURDAY. SATURDAY WILL BE ANOTHER PLEASANT DAY AND EXPECT
TEMPERATURES TO BE NEAR THE HIGH END OF GUIDANCE WITH DRY SFC AIR
HEATING UP EFFICIENTLY. MID LEVEL THETA-E ADVECTION WILL COMMENCE
SATURDAY NIGHT WITH THE INITIAL WAVE BEING SPENT ON MID LEVEL
SATURATION. GULF MOISTURE WILL BREAK FREE AND BEGIN TO STREAM
NORTHWARD SATURDAY NIGHT AS WELL WITH THE MOISTURE ADVECTION
ARRIVING LATE AIDED BY AN INCREASING LOW LEVEL JET APPROACHING 40
KTS. THE COMBINATION OF THE MULTI LEVEL KINEMATICS AND
THERMODYNAMICS WILL RESULT IN A DEEPLY FORCED SYSTEM WITH SHOWERS
AND THUNDERSTORMS ARRIVING OVER THE WEST AFTER MIDNIGHT. ADDITIONAL
CHANCES WILL CONTINUE SUNDAY AND SUNDAY NIGHT WITH AS THE SECOND
SEGMENT OF THE UPPER LEVEL SYSTEM ARRIVES ALONG WITH THE SFC LOW
REFLECTION. GENERAL AGREEMENT DEVELOPING THAT THE SFC LOW WILL SHIFT
EAST ACROSS SOUTHERN IA AND WOULD ALLOW A PORTION OF THE WARM SECTOR
TO LIFT INTO THE STATE. HIGH VARIABILITY POSSIBLE WITH HIGH
TEMPERATURES ON SUNDAY WHERE HIGHS COULD STRUGGLE IN THE 60S UNDER
INCREASING CLOUDS AND MORE PROLONGED PRECIPITATION WHILE RISING WELL
INTO THE 80S SOUTH WHERE SOME SUN COULD BE POSSIBLE. THIS COULD LEAD
TO AN AREA OF SFC BASED THUNDERSTORMS AND AN AREA WITH SEVERE
POTENTIAL. PRECIPITATION CHANCES CONTINUE OVER MAINLY THE EAST
SUNDAY EVENING BEFORE ENDING.
THE REMAINDER OF THE EXTENDED IS HIGHLIGHTED BY SEVERAL IMPULSES
RIPPLING THROUGH THE NW FLOW WHILE A DEEP UPPER LEVEL LOW DROPS INTO
ALBERTA AND MANITOBA BY MID WEEK. OVERALL TIMING BECOMES DIFFICULT
UNDER THESE SITUATIONS BUT GENERAL CONSENSUS IS A WEAK WAVE ARRIVING
TUE NIGHT INTO WED WITH A MORE SIGNIFICANT SYSTEM IMPACTING THE AREA
TOWARD THE END OF THE PERIOD AS ENERGY ASSOCIATED THE SOUTHERN
CANADA SYSTEM ARRIVES.
&&
.AVIATION...10/12Z
SOME LOW STRATUS IMPACTING NORTHERN TAF SITES INITIALLY SHOULD LIFT
INTO A SCT-BKN VFR CU DECK BY LATE MORNING. NORTHERLY TO
NORTHEASTERLY WINDS EXPECTED THROUGH THE PERIOD...MAY HAVE SOME
GUSTS BY LATE MORNING INTO THE AFTERNOON HOURS. MAINLY VFR
CONDITIONS EXPECTED BEYOND 15Z AT ALL TAF SITES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...DONAVON
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
404 AM CDT FRI AUG 10 2012
.SHORT TERM /TONIGHT/...
MAIN FOCUS TODAY WILL BE ON CLOUD COVER AND TEMPERATURES FOR THE
NEAR TERM. CWA TO REMAIN BENEATH CYCLONIC FLOW ALOFT...WITH WEAK CAA
EXPECTED THROUGHOUT THE DAY. SOME LOW LEVEL MOISTURE RESULTING IN AN
AREA OF LOW STRATUS CONTINUES TO DEVELOP OFF TO THE NORTHEAST OF THE
CWA...WITH MODEL PROGGING THIS AREA OF STRATUS TO CONTINUE TO
SPREAD/ADVECT INTO THE NORTHERN/EASTERN HALF OF THE CWA THROUGH
SUNRISE. HRRR MODEL AND GOES-R WRF FORECAST BOTH HANDLING THE
DEVELOPMENT OF THIS STRATUS WELL AND HAVE TAILORED SKY GRIDS TOWARD
THE MODEL/SATELLITE PRODUCT TRENDS. EXPECT STRATUS TO LIFT/BREAK UP
TOWARD MID/LATE MORNING ACROSS THE AREA...WITH RESULTANT MID LEVEL
CU FIELD POSSIBLE. OTHERWISE MUCH DRIER TO MOVE INTO THE CWA WITH
DEWPOINTS EXPECTED TO CONTINUE TO DROP TO AROUND 50 POSSIBLY EVEN
INTO THE 40S WITH DRIER AIR MIXING DOWN AND ADVECTING INTO THE CWA
IN NORTHERLY FLOW. WITH THE CAA...EXPECT TEMPS TO BE A FEW DEGREES
COOLER THAN YESTERDAY WITH HIGHS MAINLY IN THE UPPER 70S TO AROUND
80.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
CANADIAN HIGH PRESSURE MOVING INTO THE NORTHERN PLAINS EARLY THIS
MORNING WITH TEMPERATURES DIPPING INTO THE LOW TO MID 40S OVER THE
SOUTHEAST QUADRANT. THIS SYSTEM WILL SETTLE SOUTH TODAY AND BE
STRETCHED OVER MUCH OF THE CENTRAL AND NORTHERN PLAINS TONIGHT.
WHILE SOME MODIFICATION OF TEMPERATURES IS EXPECTED...SHOULD HAVE
OVERNIGHT LOWS TONIGHT TOUCHING THE MID 40S AT A FEW LOCATIONS
ACROSS THE NORTH AND INTO THE LOW TO MID 50S ELSEWHERE. THE CLOSED
UPPER LOW THAT AFFECTED THE AREA ON THURSDAY WILL BE SHIFTING SLOWLY
NORTHEAST ACROSS THE CENTRAL GREAT LAKES THROUGH MID DAY SATURDAY
BEFORE GAINING STEAM SATURDAY NIGHT AS ANOTHER CLOSED UPPER LOW
MOVES INTO CENTRAL CANADA. THIS WILL ALLOW A TRANSITION TO A MORE
PROGRESSIVE NORTHWEST FLOW THAT WILL PERSIST THROUGH MUCH OF THE
EXTENDED.
A FAIRLY SIGNIFICANT SYSTEM WILL ARRIVE OVER THE PACIFIC NW LATE
TODAY THEN MOVE ACROSS THE ROCKIES AND PRODUCE LEE SIDE CYCLOGENESIS
INTO SATURDAY. SATURDAY WILL BE ANOTHER PLEASANT DAY AND EXPECT
TEMPERATURES TO BE NEAR THE HIGH END OF GUIDANCE WITH DRY SFC AIR
HEATING UP EFFICIENTLY. MID LEVEL THETA-E ADVECTION WILL COMMENCE
SATURDAY NIGHT WITH THE INITIAL WAVE BEING SPENT ON MID LEVEL
SATURATION. GULF MOISTURE WILL BREAK FREE AND BEGIN TO STREAM
NORTHWARD SATURDAY NIGHT AS WELL WITH THE MOISTURE ADVECTION
ARRIVING LATE AIDED BY AN INCREASING LOW LEVEL JET APPROACHING 40
KTS. THE COMBINATION OF THE MULTI LEVEL KINEMATICS AND
THERMODYNAMICS WILL RESULT IN A DEEPLY FORCED SYSTEM WITH SHOWERS
AND THUNDERSTORMS ARRIVING OVER THE WEST AFTER MIDNIGHT. ADDITIONAL
CHANCES WILL CONTINUE SUNDAY AND SUNDAY NIGHT WITH AS THE SECOND
SEGMENT OF THE UPPER LEVEL SYSTEM ARRIVES ALONG WITH THE SFC LOW
REFLECTION. GENERAL AGREEMENT DEVELOPING THAT THE SFC LOW WILL SHIFT
EAST ACROSS SOUTHERN IA AND WOULD ALLOW A PORTION OF THE WARM SECTOR
TO LIFT INTO THE STATE. HIGH VARIABILITY POSSIBLE WITH HIGH
TEMPERATURES ON SUNDAY WHERE HIGHS COULD STRUGGLE IN THE 60S UNDER
INCREASING CLOUDS AND MORE PROLONGED PRECIPITATION WHILE RISING WELL
INTO THE 80S SOUTH WHERE SOME SUN COULD BE POSSIBLE. THIS COULD LEAD
TO AN AREA OF SFC BASED THUNDERSTORMS AND AN AREA WITH SEVERE
POTENTIAL. PRECIPITATION CHANCES CONTINUE OVER MAINLY THE EAST
SUNDAY EVENING BEFORE ENDING.
THE REMAINDER OF THE EXTENDED IS HIGHLIGHTED BY SEVERAL IMPULSES
RIPPLING THROUGH THE NW FLOW WHILE A DEEP UPPER LEVEL LOW DROPS INTO
ALBERTA AND MANITOBA BY MID WEEK. OVERALL TIMING BECOMES DIFFICULT
UNDER THESE SITUATIONS BUT GENERAL CONSENSUS IS A WEAK WAVE ARRIVING
TUE NIGHT INTO WED WITH A MORE SIGNIFICANT SYSTEM IMPACTING THE AREA
TOWARD THE END OF THE PERIOD AS ENERGY ASSOCIATED THE SOUTHERN
CANADA SYSTEM ARRIVES.
&&
.AVIATION...10/06
HIGH PRESSURE FROM CENTRAL ONT INTO SWRN NEBRASKA WILL BUILD SOUTH
INTO IOWA THROUGH THE PERIOD. VFR CONDITIONS ARE EXPECTED FOR THE
MORT PART WITH A NE-NLY FLOW OVER THE SITES. SOME FOG IS POSSIBLE
AROUND SUNRISE OVER THE NORTH WHERE WINDS WILL LIGHTEN UP AND IN THE
EAST WHERE SHOWERS MOVED THROUGH IN THE EVENING. TIMEFRAME IS
10Z-14Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...DONAVON
AVIATION...MS AUG 12
AREA FORECAST DISCUSSION
NWS GOODLAND KS
536 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 532 PM MDT SAT AUG 11 2012
WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE THROUGH THIS EVENING.
CONFIDENCE IS LOW THAT ANY WILL DIRECTLY IMPACT EITHER KGLD OR
KMCK TERMINALS. IF THEY DO...BRIEF GUSTY WINDS WILL BE THE MAIN
IMPACT..AS MOISTURE IS LIMITED AND CEILINGS WILL REMAIN VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...MENTZER
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
608 PM CDT SAT AUG 11 2012
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 148 PM CDT SAT AUG 11 2012
THE 250MB CHART FROM 11/12Z SHOWED A 70 TO 90 KNOT NORTHERLY JET
FROM SOUTHERN MANITOBA THROUGH SOUTH CENTRAL IOWA TO NORTHERN
ARKANSAS. THIS JET THEN CURVES EASTERLY TO BECOME A SOUTHERLY JET
IN THE 80 TO 100 KT RANGE, FROM EASTERN TENNESSEE THROUGH WESTERN
NEW YORK TO EASTERN QUEBEC. OVER WESTERN KANSAS, A NORTHWEST FLOW
AROUND 35 TO 40 KNOTS EXISTED. AT THE 500MB LEVEL, A LARGE CLOSED
OFF LOW PRESSURE SYSTEM WAS CENTERED OVER THE CENTRAL GREAT LAKES,
WITH A NORTH TO SOUTH ORIENTED TROUGH FROM CENTRAL QUEBEC SOUTH
THROUGH THE MIDWEST AND DOWN THROUGH MISSISSIPPI TO NEAR NEW
ORLEANS. A SMALLER SCALE WAVE WAS LOCATED OVER EASTERN MONTANA WITH
A TRAILING TROUGH OFF TO THE SOUTH THROUGH EASTERN WYOMING AND INTO
NORTHWEST COLORADO. LARGE HIGH PRESSURE REMAINED OVER NEW MEXICO
WITH LIGHT ANTICYCLONIC FLOW AROUND IT. THE 700MB PRESSURE PATTERN
WAS VERY SIMILAR TO THE 500MB LEVEL, WITH THE MONTANA SHORT WAVE A
BIT FARTHER SOUTHWEST OVER EASTERN WYOMING. THE DDC TEMP AND WIND
AT 700MB WERE +11C AND 27015KT RESPECTFULLY. THE 850MB CHART
REVEALED A LONG LOW PRESSURE TROUGH FROM SASKATCHEWAN THROUGH
EASTERN PARTS OF MONTANA, COLORADO AND NEW MEXICO TO THE TEXAS
PANHANDLE. A FIELD OF MOISTURE WAS JUST EAST OF OUR CWA. THE 850MB
TEMP AND WIND WERE +19C AND 19020KTS.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 148 PM CDT SAT AUG 11 2012
AN UPPER LEVEL SHORT WAVE CENTERED OVER SOUTHERN NORTH DAKOTA WILL
ADVANCE EAST TONIGHT, DRAGGING A LOBE OF UPPER VORTICITY THROUGH
NEBRASKA AND NORTHERN KANSAS. THIS PATTERN SHOULD SHOVE A WEAK COLD
FRONT SOUTHEASTWARD THROUGH MOST OF OUR CWA BY 12Z. PLACED THUNDERSTORM
POPS IN THE 20 PERCENT RANGE OVER OUR EXTREME NORTHWEST BY 00Z, A
LITTLE FARTHER TO THE SOUTHEAST FROM HAYS TO GARDEN CITY TO LIBERAL
BY 03Z AND POINTS EASTWARD AFTER 03Z. THESE STORMS SHOULD BE HIGH
BASED AND WILL NOT PRODUCE MUCH QPF, BUT WILL BE CAPABLE OF TAPPING
THE 600MB WINDS AND MAY PRODUCE MICROBURST GUSTS TO NEAR 50 KNOTS.
THE 700MB WINDS FROM 11/12Z SHOWED ONLY 15KTS AT THE 700MB LEVEL,
SO I AM NOT TOO CONFIDENT THERE WILL BE ANY SEVERE WINDS FROM THE
CONVECTION. THUS, I HELD OFF MENTIONING STRONG STORMS IN THE
ZONE WORDING, WILL BE BRIEF THE ONCOMING SHIFT ON THIS POTENTIAL. THE
STRONG SOUTH TO SOUTHEAST WINDS TODAY WILL SETTLE DOWN BY 04Z, AND
THIS SHOULD ALLOW TEMPERATURES TO FALL QUICKLY AFTER 06Z,
ESPECIALLY IN OUR NORTHWEST BEHIND THE FRONT. THE LOWER 60S ARE
NOT OUT OF THE QUESTION IN SYRACUSE, SCOTT CITY AND HAYS, WITH
MILDER MIN TEMPS IN THE LOWER 70S LIKELY SOUTH OF THE FRONT NEAR
MEDICINE LODGE. HAYS DROPPED TO 57F THIS MORNING. I LEFT A SMALL
AREA NEAR KIOWA IN OUR FAR SOUTHEAST ZONES WITH 16 PERCENT POPS
SUNDAY MORNING, IN CASE THE FRONT IS IN THAT VICINITY BY THEN.
SUNDAY SHOULD BE SUNNY ACROSS THE FORECAST AREA WITH AFTERNOON
TEMPERATURES WARMING INTO THE LOWER 90S IN OUR NORTH, NORTH OF I-70,
AND TO NEAR 100F IN OUR FAR SOUTHEAST NEAR PRATT, MEDICINE LODGE AND
COLDWATER. NORTH WINDS BEHIND THE FRONT WILL SERVE TO LIMIT DAY
TIME HEATING, AND SHOULD BLOW AT 15 TO 20 MPH. ALL MODELS HAVE THE
FRONT WELL SOUTH OF THE SOUTHWEST TIP OF KANSAS, AND ABOUT 45 MILES
SOUTHEAST OF OUR SOUTHEAST-MOST CORNER OF THE FORECAST AREA NEAR KIOWA.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 PM CDT SAT AUG 11 2012
MONDAY:
AN 80 KT 250 HPA JET STREAK WILL MOVE ACROSS THE NORTHERN PLAINS IN
THE WAKE OF A SYNOPTIC SHORTWAVE TROUGH. THIS IN COMBINATION WITH DIURNAL
HEATING MIGHT TRIGGER OROGRAPHICALLY INDUCED CONVECTION ACROSS COLORADO.
MEAN 700-300 HPA FLOW IS FAIRLY WEAK SO NOT VERY IMPRESSED WITH THE
OVERALL CHANCE FOR EASTERN PROPAGATION ACROSS THE REGION. FOR NOW, WILL
KEEP SLIGHT POPS ACROSS THE WESTERN ZONES.
TUESDAY:
A BETTER CHANCE FOR CONVECTION IS EXPECTED TUESDAY AS THE 12Z ECMWF
IS SHOWING ANOTHER SHORTWAVE TROUGH MOVING ACROSS KANSAS. THE REGION
SHOULD BE IN THE RIGHT ENTRANCE REGION OF A 250 HPA 75 KT JET SO UPPER
LEVEL DYNAMICS WILL BE MORE SUPPORTIVE FOR CONVECTION. WILL ADVECT
SLIGHT POPS ACROSS THE REGION THROUGH WEDNESDAY MORNING AS THE UL WAVE
SPREADS EAST.
WEDNESDAY:
A STRONGER POSITIVELY TILTED SHORTWAVE TROUGH WILL MOVE SOUTHEAST FROM
THE CANADIAN PRAIRIES AND ACROSS THE NORTHERN PLAINS. A FULL WARM AIR
ADVECTION REGIME IS EXPECTED AHEAD OF A SURFACE FRONT. MAXIMUM SFC TEMPERATURES
NEAR 98-100 DEG F ARE POSSIBLE AHEAD OF THE FRONT ASSOCIATED WITH DOWNSLOPE
ADIABATIC COMPRESSIONAL WARMING. ANY PRECIPITATION IS NOT EXPECTED UNTIL
LATE WEDNESDAY ASSOCIATED WITH ENHANCED 850-700 HPA FRONTOGENESIS THRU
THE OVERNIGHT PERIOD.
THURSDAY:
A WELCOMED CHANGE IS EXPECTED THURSDAY IN THE WAKE OF THE COLD FRONT
AS COOLER AIR SPREADS ACROSS THE PLAINS. COLD AIR ADVECTION IN THE WAKE
OF THE DEPARTING SYNOPTIC WAVE IS SHOWN BY THE ECMWF MODEL WITH TEMPERATURES
AT 850 HPA DECREASING DOWN TO 15 DEG C AND 700 HPA TEMPERATURES AROUND
5 DEG C. IN ADDITION, BOUNDARY LAYER WINDS ARE FORECAST TO BE 30-40
KT SO N/NE SURFACE WINDS SHOULD BE BREEZY BY THURSDAY MORNING. THURSDAY
IS SHAPING TO BE A GREAT DAY WITH HIGHS IN THE UPPER 70S TO LOWER 80S
DEG F, PLENTY OF CLOUDS AND SOME BENEFICIAL PRECIPITATION.
FRIDAY:
THE COOL HIGH PRESSURE CENTER WILL REMAIN ACROSS THE PLAINS FRIDAY.
HAVE GONE WITH THE COOLER ECMWF IS THE ALLBLEND LOOKS TO BE A LITTLE
ON THE WARM SIDE GIVEN THE AFOREMENTIONED COOLER AIR MASS. WINDS WILL
SLOWLY VEER SOUTHERLY BY FRIDAY EVENING BUT WILL NOT BE THAT STRONG
UNDERNEATH THE DOMINATING HIGH. A VERY PLEASANT DAY LOOKS IN STORE FOR
FRIDAY WITH A DRY FORECAST, HIGHS AROUND 80 DEG F AND FAIRLY LIGHT WINDS.
SATURDAY AND BEYOND:
A MODERATION OF TEMPERATURES IS EXPECTED SATURDAY AS 500 HPA GEOPOTENTIAL
HEIGHTS INCREASE AS A MID LEVEL RIDGE BUILDS ACROSS THE ROCKIES ALONG
WITH WARMING IN THE LOW LEVELS. HOT WEATHER MAY RETURN BY THE 20TH AS
THE 500 HPA RIDGE MOVES EAST ACROSS WESTERN KANSAS, LEE TROUGHING INTENSIFIES,
AND 850 HPA TEMPERATURES WARM INTO THE 30S DEG C. THIS WOULD SUPPORT
A DRY FORECAST WITH HIGHS IN THE UPPER 90S TO AROUND 100 DEG F.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 602 PM CDT SAT AUG 11 2012
SCATTERED HIGH BASED THUNDERSTORMS WILL PRECEDE AN UPPER LEVEL
TROUGH AS IT EXITS NORTHEAST COLORADO AND CROSSES WESTERN KANSAS
OVERNIGHT. THE BETTER LIFT FROM THIS SYSTEM WILL BE ALONG AND
NORTH OF HIGHWAY 96 SO WILL INSERT VCTS INTO THE HYS TAF WHILE
TRENDING TOWARDS LEAVING MENTION OF THUNDER OUT AT DDC AND GCK.
SOUTH/SOUTHEAST WINDS WILL SHIFT TO THE NORTH OVERNIGHT AS A COLD
FRONT/OUTFLOW BOUNDARY MOVES ACROSS WESTERN KANSAS. BASED ON 21Z
AND 22Z SURFACE OBSERVATIONS ACROSS EASTERN COLORADO/NORTHWEST
KANSAS WILL FAVOR THE QUICKER HRRR ON WIND SHIFT TIMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 96 61 89 / 20 10 10 10
GCK 62 94 59 89 / 20 10 10 20
EHA 66 95 62 91 / 30 10 10 20
LBL 65 96 60 91 / 20 10 10 20
HYS 62 91 59 86 / 20 10 0 10
P28 70 99 65 89 / 20 20 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURKE
SHORT TERM...BURKE
LONG TERM...SUGDEN
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
450 PM EDT FRI AUG 10 2012
.Forecast Update...
Issued at 445 PM EDT Fri Aug 10 2012
Updated the forecast to include 20-30% chance of rain showers over
southern Indiana and north central Kentucky this evening. A line of
showers moving south across Indiana was noted on radar early this
evening, and it looks like the line will hold together into at least
northern portions of the area. The 17Z HRRR depicts this line well
and shows it dissipating around sunset with the lack of
heating/instability.
&&
.Short Term (Today through Saturday)...
Issued at 307 PM EDT Fri Aug 10 2012
Surface cold has now cleared our forecast area. Cooler and somewhat
drier air continues to mix in from the northwest. The colder air
aloft has resulted in steep low-level lapse rates which is resulting
in a fairly extensive area of stratocumulus. The stratocu should
hang around for the next few hours and then begin to dissipate after
sunset. Regional radars do show a few light showers/sprinkles to
our north along the I-70 corridor. These will continue to move
south and may clip a few of our northern Indiana counties this
afternoon before they also dissipate after sunset. Temperatures
will likely top off this afternoon in the upper 70s to the lower 80s
and then slide off back into the 60s later this evening.
For the overnight period, latest suite of model data continue to
show plenty of cool air advection across the region. Model-time
height cross sections show some low-level moisture lingering across
the northeast sections of the forecast area. Probably will see a
gradient clouds across the region with mostly clear skies across the
west/southwest with partly cloudy skies across the
northeast/Bluegrass. As for low temps, we`ll likely see
temperatures fall into the mid-upper 50s in the north with upper 50s
to the lower 60s in the south. We generally weighted temps closer
to the weighted model consensus which has statistically done well.
Saturday looks to be a pleasant day across the Ohio Valley with
partly to mostly sunny skies as deep northwesterly flow continues
across the region. Temperatures will be quite comfortable with
highs in the upper 70s in the east with lower 80s in the central and
western sections. Mostly clear skies are expected for Saturday Night
with lows generally in the mid-upper 50s.
.Long Term (Sunday through Friday)...
Issued at 300 PM EDT Fri Aug 10 2012
A distinct pattern change will be fully in place by early this
weekend. A broad longwave trough is forecast to lie over the upper
midwest and the Great Lakes, with ridging pushed farther west across
the Intermountain West.
No excessive heat or bouts with high humidity are expected for
basically the next week as rich Gulf moisture is forecast to remain
across the southern states. On Sunday, the deep cyclone now over
eastern Michigan is expected to slowly move northeast into Quebec.
At the same time, another compact 500mb low will slide southeast
across the Missouri Valley. Both the NAM and the GFS forecast weak
low pressure to develop over Illinois Monday afternoon and move east
across the Commonwealth overnight. Although this system will lack
any robust moisture return, upper air divergence associated with the
front exit region of the upper jet may provide enough upper air
support for scattered thunderstorms during the late Monday through
early Tuesday period.
High temperatures will warm a bit from Sunday through Monday, with
Monday`s highs in the mid to upper 80s expected to nearly match the
climatological normal for mid-August.
The ECMWF is nearly alone in its forecast of scattered showers on
Wednesday. The preferred GFS depicts the Lower Ohio Valley within a
a dry northerly flow on the backside of a departing system over
western New England.
Expect a cooldown once again beginning Tuesday afternoon, with mild
temperatures continuing through Thursday. A deep cyclone forecast
north of the upper midwest on Thursday will bring a cold front and a
chance of storms for late Thursday and Friday.
&&
.Aviation (18Z TAF issuance)...
Issued at 104 PM EDT Fri Aug 10 2012
Surface cold front has passed through the terminals this morning.
Fairly thick deck of cold air stratocumulus is trailing behind the
front and will lead to cigs that remain above VFR thresholds.
Northwest winds of 8-10kts will be possible this afternoon at KSDF
and KLEX...a gust of 15-17kts will be possible at times. Further
south at KBWG, the gradient is a little weaker so only northwesterly
winds of 5-8kts is expected.
VFR conditions are expected this evening and through much of the
overnight hours. There is potential for more low clouds to move
back into the region tonight along with the possible development of
some patchy fog. KLEX and KBWG seem to be most susceptible to the
patchy fog threat with a period of MVFR visibilities being possible
between 11/07-13Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJ
Long Term........JSD
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1256 AM EDT FRI AUG 10 2012
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1145 PM EDT Thu Aug 9 2012
Updated the forecast to adjust POPs a bit. The 0Z NAM seems to have
the best handle on convection this evening. Convection over central
IN right around the sfc low should continue to move east over the
next 2-4 hrs and may develop a bit further south into our southern
Indiana counties. However, these storms should struggle to reach
severe levels given the lack of forcing further removed from the
front and main upper level wave as well as lack of instability due
to storms early this evening.
The next area of focus looks to be southern IL as wind shear
profiles increase with the upper shortwave dropping south through IL
and into western KY through the early morning hours. SPC
mesoanalysis indicates good moisture convergence along the sfc front
over southern IL with some isld-sct cells noted over western IL to
southeast MO. DCAPE values are at a relative max over southern IL
and western KY. Would expect new convection to develop over
southern IL over the next 2-4 hours, initially push SSE, and then
pivot more easterly into our area during the pre-dawn hours and as
the shortwave pivots aloft. This will probably be our best chance
for strong to severe convection overnight. Forecast confidence in
this occurring is low to medium given model inconsistencies and
banking on convection developing over southern IL.
&&
.Short Term (Tonight through Friday Night)...
Issued at 331 PM EDT Thu Aug 9 2012
...Active Period of Weather Expected This Afternoon and Tonight...
Fairly active period of weather is shaping up for the Ohio Valley
this afternoon and tonight. In the near term, mid-level shortwave
combined with surface temperatures hitting convective temperatures
has resulted in convection firing across the region. Several areas
of convection are occurring across the area. The first is an
organizing line near the I-75 corridor in our eastern sections.
This is being forced by the aforementioned mid-level wave and by
diurnal heating. This activity will continue to head east and into
WFO JKL`s area over the next hour or so. Further west, a well
defined residual outflow boundary was located along our border with
WFO IND. This boundary extends from northern Dubois county NE to
Jefferson County. Convection is firing along this boundary due to
strong moisture convergence and diurnal heating. This activity
should head east-southeast over the next few hours. Finally
additional convection is firing also over west KY. Based on the
latest runs of the LMK WRF and 4km HRRR runs, this activity should
also head east-southeast and may impact our far southwestern
counties later this afternoon. Based on RUC proximity soundings,
this afternoon`s convective activity is likely to remain in the
pulse variety with damaging winds, torrential rains and intense CG
lightning being the main threats.
Latest deterministic and ensemble model runs seem to be showing some
forecast convergence with the forecast for later this evening and
overnight. First mid-level trough will scoot east this evening
while a secondary and more potent mid-level trough dropping down
into the Ohio Valley late tonight. As this wave drops south,
surface cyclone near KSTL will shift northeast while associated
surface cold drags behind. Strong mid-level height falls will
result in widespread synoptic scale lift across the region late
tonight. This combined with forcing along the front should result
in a secondary line of convection developing to our northwest and
slide southeast overnight. Despite this line moving through during
an instability minimum, the upper level dynamics appear to be strong
enough to support convection despite the meager instability.
Current thinking is that a convective line will generate along the
I-70 corridor and then drop southeast overnight. The line will
likely be strong to possibly severe especially to our northwest.
However, as the line heads southeast, it is possible that line may
weaken a bit as it slides through KY. Convection should be pushing
through southern Indiana in the 04-06Z time frame and then through
KY in the 06-11Z time frame. Have gone ahead and bumped up PoPs for
the overnight period. Lows will remain mild with temperatures
falling into the lower-mid 60s in the northwest and mid-upper 60s
elsewhere.
For Friday, the main forecast change here is that a lot more cloud
cover will be likely during the morning hours. Latest model
time-height model cross sections show plenty of low-level moisture
lingering behind the frontal boundary as it pushes through. Thus,
mostly cloudy skies seem very likely in the morning followed by
progressive clearing during the afternoon and into the evening
hours. Highs tomorrow will be quite cool compared to what we`ve
seen over the last few months. We should see readings in the upper
70s in the east with upper 70s to lower 80s in the central and
west. Lows Friday night will be quite comfortable with lows in the
mid-upper 50s.
.Long Term (Saturday through Thursday)...
Issued at 315 PM EDT Thu Aug 9 2012
...Mostly Sunny, Dry, and Cool Weekend Ahead...
A vertically stacked unseasonably far south and strong closed low
will begin to slowly fill over Lake Huron Saturday. This system will
slowly weaken and slowly lift north towards St. James Bay by late
Sunday. In its wake, it will leave residual troughing across the
western Great Lakes and the upper Midwest.
By early Saturday, the occluded front related to this upper low will
already have moved well east of the Commonwealth. Much drier and
cooler air originating in Canada, will have overspread the state by
dawn Saturday.
Expect mostly clear skies and relatively cool temperatures for the
upcoming weekend. Dewpoints will likely fall into the lower 50s by
Saturday afternoon. Highs will struggle to exceed 80 on Saturday
with highs on Sunday warming just a few degrees into the lower 80s.
Overnight lows early Sunday will quite likely reach into the upper
50s, with perhaps our urban areas remaining near 60.
A broad longwave trough will remain centered roughly over the Great
Lakes during the early portion of next week. This will ensure no
repeat of the excessively hot temperatures of early August anytime
soon. Both the latest GFS and the ECMWF show a disturbance sliding
southeast towards the base of this longwave trough Monday and
Tuesday. This system will approach the Commonwealth by late Monday.
At the surface, this system will likely aid in the formation of a
weak surface trough that may serve as a focus for convection
beginning late Monday, possibly continuing through the bulk of
Tuesday. Will introduce a chance of storms for the later half of
Monday, extending through Tuesday.
Temperatures will warm a bit within the Monday through Thursday time
period. However, even by Wednesday through Friday, temperatures
will not exceed our seasonal mid-August averages with highs
remaining in the upper 80s to around 90
&&
.Aviation (06Z TAF issuance)...
Issued at 1255 AM EDT Fri Aug 10 2012
Main focus overnight will be convective chances ahead of a cold
frontal passage. Currently, frontal boundary appears to be oriented
along, but just north of the Ohio River and will remain nearly
stationary for a few more hours. Then, a potent upper level wave
will swing through the area toward dawn, helping to usher the
surface front through. Chances for showers and storms will continue
until this passage occurs later this morning, with the best chance
of a storm at SDF. Am not confident enough to go with a prevailing
thunder group at this time so will leave VCTS/CB mention until 7 AM
EDT.
Frontal boundary looks to move through the TAF sites sometime
between 6 AM and 11 AM with a brief potential for low MVFR or IFR
ceilings. Surface winds will also veer to westerly and then
northwesterly through the end of the forecast period with the
passage. Speeds should generally be around 10 mph. Ceilings should
improve through midday and the afternoon, however at least MVFR
stratocu will again be possible overnight tonight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJ
Long Term........JSD
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
253 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STATIONARY FRONT NEAR THE COAST WILL GRADUALLY MOVE NORTH
ACROSS THE REGION AS A WARM FRONT TODAY AND TONIGHT. LOW PRESSURE
WILL PASS TO THE WEST OF THE STATE SATURDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
STRONG LOW PRESSURE IS EXPECTED TO MOVE THROUGH THE GREAT LAKES
TONIGHT INTO SATURDAY. EXPECT HEAVIER PRECIPITATION ACROSS THE
NORTH TONIGHT IN ADVANCE OF PRIMARY LOW THEN FOCUS WILL SHIFT TO
COAST SATURDAY AS SECONDARY WAVE DEVELOPS ALONG COAST. FOR POPS
HAVE USE THE RUC13 INTO EARLY EVENING THEN TRANSITION OF GFS LATER
IN EVENING THEN TO MODEL BLEND OF THE NAM12...GFS40...SREF...CMCREG
AND ECMWF. WILL ALSO BLEND THE SAME GUIDANCE FOR QPF EXCEPT USE
THE NAM80. WILL MAKE SOME MANUAL ADJUSTMENTS TO SMOOTH
PRECIPITATION AREAS. FOR TEMPERATURE AND DEW POINT USED GMOS AND
WILL ADJUST MAXIMUM TEMPERATURE A FEW DEGREES HIGHER SATURDAY.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
A CLOSED H5 LOW OVER SOUTHERN QUEBEC OPENS UP AND LIFTS INTO THE
NORTHERN CANADIAN MARITIMES. A DISTURBANCE ROTATING AROUND THE H5
LOW COULD BE THE TRIGGER FOR SUNDAY AFTERNOON AND EVENING
THUNDERSTORMS. WEATHER CONDITIONS IMPROVE SUNDAY NIGHT AND MONDAY
AS THE LOW MOVES TO THE NORTHEAST OF MAINE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE EXTENDED MODELS ARE CONTINUE TO DISAGREE ON A SYSTEM MOVING
THROUGH THE MID-WEST AT THE START OF THE PERIOD...HOWEVER ARE IN
GOOD GENERAL AGREEMENT ELSEWHERE THROUGH MOST OF THE PERIOD.
THE GFS IS SHOWING A LOW PRESSURE SYSTEM OVER ERN QUEBEC WITH ITS
FRONT WRAPPED AROUND THE LOW THROUGH NRN ME...THEN OUT ACROSS THE
MARITIMES. A WEAK HIGH PRESSURE RIDGE BUILDING NORTH ALONG THE
ATLANTIC COAST STATES. A LOW PRESSURE SYSTEM OVER THE SE OF JAMES
BAY...WITH A FRONTAL SYSTEM EXTENDING SOUTH THROUGH THE LAKE
MICHIGAN...TO A SECOND LOW OVER CHICAGO...THEN SOUTH TO ERN TEXAS.
THE ECMWF HAS THE LOW OVER SRN JAMES BAY...A LOW OVER ST
LOUIS...ANOTHER OVR ERN TEXAS...IT DOESN`T SUPPORT THE FRONTAL
SYSTEM TROUGH THE GREAT LAKES TO ST LOUIS. THE GFS SHOW BETTER
UPPER LEVEL SUPPORT WITH A SHORTWAVE DIGGING SOUTH TO NRN LA. THE
ECMWF DIGS THE SHRTWV TO SRN MO. TUESDAY MORNING THE GFS DEEPENS
THE LOW OVER CHICAGO AND MOVES IT EAST TO DETROIT. MAINTAINS THE
FRONT EXTENDING SOUTH TO WRN LA WITH A COUPLE MINOR LOWS. THE
ECMWF SHOWS SOME DEVELOPMENT OF THE LOW OVER ST LOUIS...MAINTAINS
IT NEARLY STATIONARY. THIS TREND CONTINUE TO TUESDAY EVENING...THE
GFS DEEPENS THE LOW FARTHER AND MOVES IT EAST TO THE ERN GREAT
LAKES REGION. THE SHORTWAVE TO NRN FL. THE GFS ALSO SHOWING GOOD
COLD AIR ALOFT TO SUPPORT THE SFC DEVELOPMENT. THE ECMWF CONTINUE
TO SHOW DEVELOPMENT OF THE SYSTEM...NOT TO THE EXTEND OF THE GFS.
SHORT WAVE SUPPORT HAS NO SIGNIFICANT CHANGE FROM PREVIOUS. BY
WEDNESDAY MORNING THE CONTRAST CONTINUES. THE GFS FURTHER DEEPENS
THE LOW OVER THE ERN GREAT LAKES. THE FROTN EXTENDING THROUGH SRN
NEW ENGLAND TO A SECOND LOW OVER DELMARVA. A DEEP SHORT WAVE
EXTENDING TO NRN FL...THE UPPER RIDGE BUILDING TO SRN HUDSON BAY.
THE ECMWF CONTINUE TO SHOW A DISORGANIZED SYSTEM MOVING THROUGH
NEW ENGLAND. THE SHORTWAVE TROUGH FILLING....AND NO SIGNIFICANT
RIDGE. BOTH MODELS ARE SHOWING A NEW LOW MOVING INTO WRN PLAINS
FROM CANADA TO NRN TX. THROUGH THURSDAY EVENING THE GFS MAINTAINS
THE LOW OVR THE ERN GREAT LAKES MOVES IT EAST TO SOUTHCOAST...THE
SFC AND 500MB LOW VERTICALLY STACKED. A SHARP UPR LVL RIDGE
THROUGH THE CNTRL GREAT LAKES. THE NEW LOW EAST TO SRN HUDSON
BAY...ITS FRONT SOUTH TO NRN TX. THE ECMWF CONTINUE TO SHOW A
DISORGANIZED SYSTEM WITH THE LOW MOVING EAST THROUGH QUEBEC INTO
THE WRN MARITIMES BY THURSDAY EVENING. THE NEW LOW THE SAME AS THE
GFS. BY END OF PERIOD. THE GFS MAINTAINS THE COLD LOW IN THE GULF
OF MAINE...THE ECMWF CONTINUES THE COLD LOW IN THE WRN MARITIMES.
THE NEW LOW ON BOTH MODELS OVR SRN HUDSON BAY...WITH A COLD FRONT
EXTENDING SOUTH THROUGH THE CNTRL GREAT LAKES. THRU KY...AR...INTO
TX. BOTH MODELS SHOW MINOR LOWS ALONG THE BOUNDARY.
THE GFS AND ECMWF CONTINUE TO DISAGREE ON THE FIRST
SYSTEM...TODAY THERE WAS A MORE PRONOUNCED DIFFERENCES IN THE
UPPER LEVEL GUIDANCE THAN IN PREVIOUS RUNS.
LOADED GMOS WITH MINOR SMOOTHING OF THE SKY AND POP GRIDS.
ADJUSTED POPS DOWN WHERE CLOUD COVER DID NOT SUPPORT PCPN. LOADED
NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. PLUS 25 PERCENT TO WNDS
FOR GUST OVR COASTAL WATERS...15 PERCENT OVER LAND.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
NEAR TERM: EXPECT IFR CONDITIONS DUE TO LOW CEILINGS NORTH AND
LOW CEILING AND FOGS SOUTH.
SHORT TERM: IFR/MVFR CIGS AND VSBYS WILL BE POSSIBLE AT TAF SITES
SATURDAY NIGHT...EARLY SUNDAY MORNING AND AGAIN SUNDAY NIGHT IN
SHOWERS...THUNDERSTORMS AND PATCHY FOG.
&&
.MARINE...
NEAR TERM: HAVE BLENDED THE NAM12 AND GFS40 FOR WIND GRIDS THEN
REDUCED BLENDED VALUE BY 20 PERCENT TO ADJUST FOR STRONG MARINE
LAYER OVER COLDER SEA SURFACE TEMPERATURE. FOR WAVES: SOUTHERLY
FETCH AREA TO DEVELOP THIS EVENING SOUTH AND EAST OF NEW ENGLAND.
EXPECT THIS AREA TO RESULT IN SOUTHERLY WAVE GROUP 170/7 SECONDS
BASE ON WNA SPECTRAL. THINK WNA OVER ESTIMATING THIS GROUP WITH
SURFACE WIND TOO HIGH. SECONDARY LONG PERIOD WAVE GROUP FROM 140/9
SECONDS 1-2 FEET VALID BASED ON SPECTRAL DENSITY FROM 44027. WILL
USE SWAN/NAM WAVES AND REDUCE BY 1 FOOT THROUGH PERIOD.
SHORT TERM: WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW SCA
CRITERIA SUNDAY AND MONDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...OKULSKI
LONG TERM...NORTON
AVIATION...MIGNONE
MARINE...MIGNONE/OKULSKI
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
929 PM EDT SAT AUG 11 2012
.SYNOPSIS...
LOW PRESSURE WILL SLOWLY MEANDER NORTHEASTWARD THIS EVENING
KEEPING CLOUDS IN THE AREA. MIDWEST HIGH PRESSURE WILL BREAK UP
THE CLOUDS SUNDAY PROVIDING FOR SUNNY...PLEASANT CONDITIONS
THROUGH THE START OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
WITH 930PM UPDATE...PREVIOUS FORECAST LOOKS GOOD WITH NO
SIGNIFICANT CHANGES. PREVIOUS DISCUSSION FOLLOWS.
STACKED UPPER LEVEL LOW WILL CONTINUE TO WRAP LOW LEVEL MOISTURE
AND CLOUDS OVER MOST OF THE REGION FOR THE REST OF TODAY AND
TONIGHT. SHOWERS FOR THE REMAINDER OF THE EVENING/NIGHT SHOULD
GENERALLY BE CONFINED TO AREAS NORTH OF PITTSBURGH AS AN UPPER
LEVEL SHORTWAVE ROTATES THROUGH THE FLOW. OTHERWISE HEAVIER
SHOWERS/THUNDERSTORMS WILL GENERALLY REMAIN OVER LAKE ERIE
ENHANCED BY THE LAKE ITSELF.
THE UPPER LEVEL JET WILL HELP TO LIFT THE LOW FURTHER INTO CANADA
OVERNIGHT BRINGING AN END TO SHOWERS BY EARLY SUNDAY. AS THE COLD
POOL RETREATS SO WILL THE CLOUD COVER...WHICH SHOULD ALLOW
TEMPERATURES TO MODERATE TO A FEW DEGREES WARMER THAN THEY ARE
TODAY. STILL...WITH 850MB TEMPERATURES NEAR 10C...TEMPERATURES
ARE STILL EXPECTED TO BE ROUGHLY 5-10 DEGREES BELOW NORMAL FOR
AUGUST AND MORE INDICATIVE OF FALL.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE LOW LATER SUNDAY AFTERNOON
AND SHOULD KEEP MONDAY DRY. THERE CONTINUES TO BE SLIGHT TIMING
AND DEPTH ISSUES WITH THE NEXT SHORTWAVE THAT WILL APPROACH LATE
MONDAY/TUESDAY. WILL MAINTAIN A BLEND OF THE MODEL SOLUTIONS WITH
TIMING A BIT SLOWER THAN THE 00Z ECMWF BUT FASTER THAN THE SREF.
WILL START TO BRING IN CLOUDS LATE MONDAY WITH THE APPROACH OF THE
SYSTEM BUT DELAYED POPS UNTIL TUESDAY MORNING. TEMPERATURES SHOULD
MODERATE TO NEAR NORMAL VALUES THROUGH THE SHORT TERM...WHICH IS
ROUGHLY A BLEND OF THE NAM AND GFS MOS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WITH MODEL DISCREPANCIES STILL APPARENT...DECIDED TO FOLLOW CLOSE
TO HPC GUIDANCE FOR THE EXTENDED MAINTAINING A CHANCE FOR SHOWERS
TUESDAY NIGHT AND EARLY WEDNESDAY AS THE SHORTWAVE MOVES THROUGH.
THEN...HIGH PRESSURE SHOULD BUILD OVERHEAD FOR THE MIDDLE OF THE
WEEK THROUGH THURSDAY BEFORE ANOTHER SYSTEM APPROACHES AT THE END
OF THE PERIOD. TEMPERATURES WILL BE NEAR NORMAL.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
UPPER LOW OVER GREAT LAKES WILL CONTINUE TO LIFT NORTHWARD
OVERNIGHT. COMBINATION OF WEAK AREAS OF MID-TROPOSPHERIC UPWARD
VERTICAL VELOCITIES SPINNING AROUND UPPER LOW, COLD AIR ALOFT AND
CYCLONIC SUFFRAGE FLOW CREATING LOWER LEVEL LIFT...WILL PRODUCE
SCATTERED AREAS OF LIGHT SHOWERS/RAIN/DRIZZLE. HOWEVER EXPECT
VISIBILITIES TO GENERALLY STAY 3-5SM OR BETTER. SOME FOG POSSIBLE
TOWARD MORNING. MOS GUIDANCE AND HRRR SUGGEST SOME DECREASE IN
CEILINGS OVERNIGHT. HRRR FOCUSING ON NORTH (FKL AND DUJ). KEPT
MOST TERMINALS 4-5+ IN FOG TOWARD MORNING. HOWEVER...AT FKL WENT
3SM BR. WINDS TO DIMINISH AND BECOME LIGHT SW OVERNIGHT. STRATO-CU
STILL AROUND IN MORNING AND SCATTERING OUT FROM SW TO NE. THINK IT
WILL TAKE UNTIL AFTERNOON FOR SC DECK TO SCATTER OUT FROM PIT-AGC
AND NORTH. VFR BY LATER IN AFTERNOON ALL TERMINALS AND EXTENDING
INTO SUNDAY EVENING.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
NEXT WEATHER SYSTEM APPROACHES ON TUESDAY WITH CHANCE OF
RESTRICTIONS IN SCATTERED SHOWERS AND THUNDERSTORMS. SOME
LINGERING SHOWERS EARLY WEDNESDAY AND THEN HIGH PRESSURE BUILDS
ACROSS REGION FOR REMAINDER OF WEDNESDAY INTO THURSDAY WITH VFR
CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
732 PM EDT SAT AUG 11 2012
.SYNOPSIS...
LOW PRESSURE WILL SLOWLY MEANDER NORTHEASTWARD THIS EVENING
KEEPING CLOUDS AND A SLIGHT CHANCE FOR SHOWERS THROUGH TONIGHT.
MIDWEST HIGH PRESSURE WILL BREAK UP THE CLOUDS SUNDAY PROVIDING
FOR SUNNY...PLEASANT CONDITIONS THROUGH THE START OF THE WORK
WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
WITH 6PM UPDATE...BUMPED UP SKY COVER SLIGHTLY...WITH NEARLY
OVERCAST SKIES OBSERVED ON SATELLITE. CAN STILL SEE SOME SPOTTY
SHOWERS OUT THERE...BUT THINK THINGS WILL TRANSITION MORE TO
DRIZZLE/MIST OVERNIGHT. NO OTHER MAJOR CHANGES. PREVIOUS
DISCUSSION FOLLOWS.
STACKED UPPER LEVEL LOW WILL CONTINUE TO WRAP LOW LEVEL MOISTURE
AND CLOUDS OVER MOST OF THE REGION FOR THE REST OF TODAY AND
TONIGHT. SHOWERS FOR THE REMAINDER OF THE EVENING/NIGHT SHOULD
GENERALLY BE CONFINED TO AREAS NORTH OF PITTSBURGH AS AN UPPER
LEVEL SHORTWAVE ROTATES THROUGH THE FLOW. OTHERWISE HEAVIER
SHOWERS/THUNDERSTORMS WILL GENERALLY REMAIN OVER LAKE ERIE
ENHANCED BY THE LAKE ITSELF.
THE UPPER LEVEL JET WILL HELP TO LIFT THE LOW FURTHER INTO CANADA
OVERNIGHT BRINGING AN END TO SHOWERS BY EARLY SUNDAY. AS THE COLD
POOL RETREATS SO WILL THE CLOUD COVER...WHICH SHOULD ALLOW
TEMPERATURES TO MODERATE TO A FEW DEGREES WARMER THAN THEY ARE
TODAY. STILL...WITH 850MB TEMPERATURES NEAR 10C...TEMPERATURES
ARE STILL EXPECTED TO BE ROUGHLY 5-10 DEGREES BELOW NORMAL FOR
AUGUST AND MORE INDICATIVE OF FALL.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE LOW LATER SUNDAY AFTERNOON
AND SHOULD KEEP MONDAY DRY. THERE CONTINUES TO BE SLIGHT TIMING
AND DEPTH ISSUES WITH THE NEXT SHORTWAVE THAT WILL APPROACH LATE
MONDAY/TUESDAY. WILL MAINTAIN A BLEND OF THE MODEL SOLUTIONS WITH
TIMING A BIT SLOWER THAN THE 00Z ECMWF BUT FASTER THAN THE SREF.
WILL START TO BRING IN CLOUDS LATE MONDAY WITH THE APPROACH OF THE
SYSTEM BUT DELAYED POPS UNTIL TUESDAY MORNING. TEMPERATURES SHOULD
MODERATE TO NEAR NORMAL VALUES THROUGH THE SHORT TERM...WHICH IS
ROUGHLY A BLEND OF THE NAM AND GFS MOS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WITH MODEL DISCREPANCIES STILL APPARENT...DECIDED TO FOLLOW CLOSE
TO HPC GUIDANCE FOR THE EXTENDED MAINTAINING A CHANCE FOR SHOWERS
TUESDAY NIGHT AND EARLY WEDNESDAY AS THE SHORTWAVE MOVES THROUGH.
THEN...HIGH PRESSURE SHOULD BUILD OVERHEAD FOR THE MIDDLE OF THE
WEEK THROUGH THURSDAY BEFORE ANOTHER SYSTEM APPROACHES AT THE END
OF THE PERIOD. TEMPERATURES WILL BE NEAR NORMAL.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
UPPER LOW OVER GREAT LAKES WILL CONTINUE TO LIFT NORTHWARD
OVERNIGHT. COMBINATION OF WEAK AREAS OF MID-TROPOSPHERIC UPWARD
VERTICAL VELOCITIES SPINNING AROUND UPPER LOW, COLD AIR ALOFT AND
CYCLONIC SUFFRAGE FLOW CREATING LOWER LEVEL LIFT...WILL PRODUCE
SCATTERED AREAS OF LIGHT SHOWERS/RAIN/DRIZZLE. HOWEVER EXPECT
VISIBILITIES TO GENERALLY STAY 3-5SM OR BETTER. SOME FOG POSSIBLE
TOWARD MORNING. MOS GUIDANCE AND HRRR SUGGEST SOME DECREASE IN
CEILINGS OVERNIGHT. HRRR FOCUSING ON NORTH (FKL AND DUJ). KEPT
MOST TERMINALS 4-5+ IN FOG TOWARD MORNING. HOWEVER...AT FKL WENT
3SM BR. WINDS TO DIMINISH AND BECOME LIGHT SW OVERNIGHT. STRATO-CU
STILL AROUND IN MORNING AND SCATTERING OUT FROM SW TO NE. THINK IT
WILL TAKE UNTIL AFTERNOON FOR SC DECK TO SCATTER OUT FROM PIT-AGC
AND NORTH. VFR BY LATER IN AFTERNOON ALL TERMINALS AND EXTENDING
INTO SUNDAY EVENING.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
NEXT WEATHER SYSTEM APPROACHES ON TUESDAY WITH CHANCE OF
RESTRICTIONS IN SCATTERED SHOWERS AND THUNDERSTORMS. SOME
LINGERING SHOWERS EARLY WEDNESDAY AND THEN HIGH PRESSURE BUILDS
ACROSS REGION FOR REMAINDER OF WEDNESDAY INTO THURSDAY WITH VFR CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1151 PM EDT SAT AUG 11 2012
.AVIATION...
//DISCUSSION...
THE UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO MOVE OFF TO THE
NORTHEAST...LEADING TO A DIMINISHING TREND TO THE MID LEVEL CLOUDS
AS DRIER AIR NUDGES IN FROM THE WEST. WARMING ALOFT THIS MORNING
WILL DEVELOP A SHALLOW HIGH BASED INVERSION...WHICH MAY SUSTAIN
CLOUDS BASED BETWEEN 5K AND 7K FT THROUGH DAYBREAK. THE SFC GRADIENT
WILL CONTINUE TO RELAX THROUGH THE EARLY MORNING. SOME WEAK LOW
LEVEL DRY AIR ADVECTION AND OCCASIONAL CLOUD COVER WILL BE TWO
LIMITING FACTORS FOR FOG FORMATION. GIVEN THE SATURATED SOILS...A
BRIEF MENTION OF SOME MVFR VSBYS IN FOG AROUND DAYBREAK CONTINUES TO
LOOK WARRANTED.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE ON POTENTIAL FOR CEILINGS BELOW 5000 FT TO
REDEVELOP SUNDAY AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 340 PM EDT SAT AUG 11 2012
SHORT TERM...THIS EVENING AND TONIGHT
THE CLOSED CIRCULATION OF THE BAROTROPIC UPPER LEVEL PRESSURE SYSTEM
REMAINS CENTERED OVER PORTIONS OF FAR SOUTHWESTERN ONTARIO THIS
AFTERNOON. THIS POSITIONING FOR THE PAST 6HRS SEEMS TO HAVE BEEN A
RESULT OF A LAKE AGGREGATE EFFECT OFF OF THE CENTROID OF THE CENTRAL
GREAT LAKES. THE EFFECTIVE REACH OF THE LOW HAS BEEN GREAT ENOUGH TO
KEEP THE ENTIRETY OF EASTERN LOWER MICHIGAN UNDER A VEIL OF LOW TO
MIDLEVEL STRATUS. EROSION OF THE WESTERN EDGE OF THE CLOUDS IS
TAKING PLACE AS WE/RE CURRENTLY SEEING SOME CELLULAR BASED CLOUD
SCALE CIRCULATIONS/SUBSIDENCE BRINGING SOME INCREASED SUNSHINE AT
THE WESTERN CWA DOORSTEP. EVEN IF THIS OCCURS...TIME IS RUNNING OUT
TO SALVAGE MUCH IF ANY OF THE TODAY PERIOD. MAY SEE A 3-5 DEGREE
SPIKE IF THAT OCCURS...MERELY PUTTING US AT THE FORECASTED HIGH
VALUES FOR TODAY.
SUBTLE TROUGH AXIS WILL PUSH TO THE LAKE ERIE APPENDAGE PRIOR TO
00Z. THIS WILL OFFER ADDITIONAL SUPPORT FOR A CONTINUATION OF THE
GRADIENT FLOW RIGHT UP TO THE ADVENT OF THE EVENING ALONG WITH THE
SUBSEQUENT EVAPORATION/DRYING OF THE LOW LEVEL TROPOSPHERE.
SOUTHEASTERN MICHIGAN WILL RESIDE IN A GENERAL AREA OF DIFFERENTIAL
AVA THROUGH THE EVENING HOURS PER RAP-FORMERLY RUC. THIS RAP DATASET
ALSO SEEMS TO HAVE A REASONABLE HANDLE OF THE CYCLONIC VORTICITY
FILAMENT NOW EXITING THE FAR EAST. THUS...FOR THE REMAINDER OF THE
AFTERNOON/EARLY EVENING WILL BE LOOKING AT POTENTIAL FOR SMALLISH
WAVES OF LIGHT SHOWERS/DRIZZLE BUT NOT ANTICIPATING MUCH IN THE WAY
OF WIDESPREAD HEAVY PRECIPITATION. LOSS OF INSOLATION THIS EVENING
SHOULD SHUT EVERYTHING DOWN WITH TIME. ELEVATED LEVELS OF NEAR
SURFACE MOISTURE BRINGS PROSPECTS OF FOG TOWARDS MORNING ESPECIALLY
IF CLOUD COVER TOTALLY DISSIPATES. NOT SEEING A GREAT MODELED
MOISTURE PROFILE FOR FOG TONIGHT AND WILL LEAVE PATCHY MENTION IN
THE GRIDS...BEST POTENTIAL SHOULD BE IN LOW LYING AREAS. LACK OF
ADVECTION WILL LIKELY KEEP LOWS IN THE MIDDLE TO UPPER 50S.
LONG TERM...SUNDAY THROUGH SATURDAY
ACTIVE WEATHER PATTERN WILL CONTINUE DURING THE UPCOMING WEEK WITH
TWO MAJOR SYSTEM SLATED TO TRAVEL THROUGH THE GREAT LAKES...BOTH
BRINGING THE CHANCE OF WIDESPREAD RAINFALL. THESE SYSTEMS WILL BE
TRACKING INTO THE AREA WITHIN MEAN NORTHWEST UPPER FLOW...WITH THIS
PATTERN ESSENTIALLY KEEPING TEMPERATURES NEAR AVERAGE FOR WARMEST
DAYS IMMEDIATELY PRECEDING THESE STORM SYSTEMS AS SHORTWAVE RIDGING
TRANSLATES THROUGH THE AREA TO BELOW AVERAGE AFTER IN THE WAKE OF
THESE SYSTEMS AS COLD AIR ADVECTION AND RESIDUAL MOISTURE AND CLOUD
COVER HOLDS TEMPERATURES DOWN. THE COOLEST AIRMASS WILL HOLD OFF
UNTIL LATE IN THE FORECAST PERIOD AS SECOND SHORTWAVE TAPS A FAIR
AMOUNT OF FALL-LIKE AIR AS IT DROPS ACROSS CANADA INTO THE LAKES
REGION.
THE FIRST SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY CHURNING EAST
ACROSS THE US ROCKIES NEAR THE MONTANA AND WYOMING STATE LINE. ITS
COUNTERPART IS ANOTHER SHORTWAVE WHICH IS TRACKING OVER THE CANADIAN
ROCKIES. BOTH VORTICITY CENTERS ARE QUITE WELL DEVELOPED ALREADY.
THE POSITIONING OF THE SOUTHERN SHORTWAVE WILL FAVOR AN EVENTUAL
TRACK OF THE MAIN ENERGY ACROSS THE NORTHERN OHIO VALLEY/SOUTHERN
GREAT LAKES...WHICH WILL BE FAVORABLE FOR A FAIRLY WIDESPREAD AND
STEADY RAIN ACROSS THE AREA. MODELS HAVE REMAINED RATHER CONSISTENT
RUN TO RUN AS WELL AS IN RESPECT TO EACH OTHER IN BRINGING THIS
STORM SYSTEM INTO THE AREA LATE MONDAY...HAVING THE BULK OF THE
RESULTING PRECIPITATION EVENT OCCUR MONDAY NIGHT...AND THEN HOLDING
ONTO LINGERING SHOWERS INTO TUESDAY. WILL NOT ADJUST FORECAST MUCH
OTHER THAN TO INCREASE PRECIPITATION CHANCES SLIGHTLY AS CONFIDENCE
IN THIS SCENARIO CONTINUES TO INCREASE.
THE SECOND SYSTEM...STILL WELL OFF THE CANADIAN WEST COAST...WILL
EVENTUALLY COME ONSHORE OVER BRITISH COLUMBIA AND TAP A LARGER CHUNK
OF COLDER AIR AS THE NORTHERN STREAM COMPONENT OF THE JET ENERGY
REMAINS DOMINANT AS IT CROSS NOAM. THIS WILL RESULT IN A SURFACE LOW
TRACKING THROUGH SOUTHERN CANADA AND JUST BRUSHING THE NORTHERN
GREAT LAKES. THIS LOW WILL FORCE A STRONG COLD FRONT THROUGH THE
GREAT LAKES AS IT WRAPS UP INTO THE JAMES BAY/HUDSON BAY AREA. THE
TIMING IS SLIGHTLY MORE ELUSIVE...BUT FOR A DAY 6/7 FORECAST...THE
CONFIDENCE REMAINS HIGHER THAN NORMAL AS MODELS SUGGEST A THURSDAY
NIGHT INTO FRIDAY TIME FRAME. THIS SCENARIO...WITH THE MAIN SYSTEM
NORTH OF THE REGION...SUPPORTS A LINE OR LINES OF CONVECTION IN
ADVANCE OR WITH THE COLD FRONTAL PASSAGE...FOLLOWED BY WRAPAROUND
MOISTURE AND EVEN SOME LAKE EFFECT/ENHANCED SHOWER ACTIVITY HEADING
INTO THE WEEKEND AS THE COOLER AIR INTERACTS WITH RELATIVELY WARM
LAKE WATERS. SO...OVERALL...WHILE RAIN CHANCES LOOK PRETTY GOOD AT
THIS POINT...THIS ACTIVITY WILL BE SHORTER LIVED AND MORE SCATTERED
IN NATURE THAN THE SYSTEM EARLY IN THE WEEK.
AS ELUDED TO EARLIER...TEMPERATURES WILL OSCILLATE BETWEEN AVERAGE
AND BELOW AVERAGE WITH THE APPROACH AND THEN DEPARTURE OF THESE
STORM SYSTEMS. THIS WILL BRING HIGH TEMPERATURES AROUND 80 EARLY IN
THE WEEK AND AGAIN WEDNESDAY/THURSDAY...WITH HIGHS CLOSER TO 70
TUESDAY AND 70 OR LESS FRIDAY INTO SATURDAY. LOWS WILL RANGE IN THE
UPPER 50S TO LOWER 60S UNTIL THE LAST PART OF THE FORECAST PERIOD
WHEN LOWS AROUND 50 WILL BE MORE COMMON AS THE COLDER AIRMASS SPILLS
INTO THE AREA. IN FACT...A FEW READINGS IN THE 40S SEEM PROBABLE BY
NEXT WEEKEND IF THE CURRENT BASIC STORM TRACK SCENARIO HOLDS CLOSE
TO CURRENT PROJECTIONS.
MARINE...
THE BROAD LOW PRESSURE CENTER CIRCULATION IS IN PLACE OVER FAR
SOUTHERN LAKE HURON THIS AFTERNOON. OVERALL...THE WEAK SFC LOW
FEATURE HAS KEPT CONDITIONS RELATIVELY IN CHECK GIVEN THE ANOMALOUS
PARENT UPPER LEVEL SYSTEM. THE AREA WATERS ARE EXPERIENCE SOME LOW
STABILITY CONDITIONS WHICH WILL MAINTAIN THE RESIDUAL CHOPPY SEA
STATE THROUGH THE TONIGHT PERIOD. THIS IS HANDLED IN THE NEARSHORE
ZONES WITH SMALL CRAFT ADVISORIES THAT ARE IN EFFECT UNTIL 2Z THIS
EVENING. WAVE HEIGHTS SHOULD TRANSLATE QUICKLY AWAY FROM THE US
WATERS OVERNIGHT...AND THE DECISION WAS MADE TO MAINTAIN THE
INHERITED TIMING OF HEADLINES. BUILDING HIGH PRESSURE WILL BRING
MUCH CALMER CONDITIONS LATE SUNDAY AND SUNDAY NIGHT. AN APPROACHING
TROUGH OF LOW PRESSURE WILL ADVANCE INTO THE GREAT LAKES REGION BY
MONDAY NIGHT...POTENTIALLY SUPPORTING A SURFACE LOW CENTER THAT
WOULD TRACK THROUGH SOUTHEASTERN MICHIGAN ON TUESDAY.
AVAILABLE MODEL GUIDANCE IS NOT VERY STRONG WITH THE LAKE EFFECT
POTENTIAL OF SHOWERS AND TSTORMS OVERNIGHT. WITH THAT SAID...PATTERN
RECOGNITION SUGGESTS CONVECTION WILL BE POSSIBLE THROUGHOUT THE
NIGHT. GIVEN THE STABILITY AND VORTICITY RICH
ENVIRONMENT....WATERSPOUTS WILL BE POSSIBLE WITH ANY ACTIVITY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
SHORT TERM...CB
LONG TERM....DG
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 PM EDT SAT AUG 11 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 736 PM EDT SAT AUG 11 2012
UNDER DRY AIR MASS ASSOCIATED WITH HIGH PRES DRIFTING OVER THE UPPER
LAKES...EXPECT VFR CONDITIONS THRU THE FCST PERIOD AT KIWD/KCMX/KSAW.
THERE MAY BE SOME SHALLOW RADIATIONAL FOG AT KIWD TONIGHT...SIMILAR
TO LAST NIGHT...BUT SHOULD BE BRIEF/INTERMITTENT.
&&
.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 DETROIT/PONTIAC MI
701 PM EDT SAT AUG 11 2012
.AVIATION...
//DISCUSSION...
SOME DRY AIR ENTRAINMENT ON THE WESTERN EDGE OF THE CLOUD SHIELD
OVER WESTERN MI WILL CONTINUE TO FUNNEL INTO SE MI THIS EVENING. THE
EFFECT WILL BE A CONTINUED STEADY RISE IN CEILING HEIGHTS OVER THE
NEXT ONE TO THREE HOURS. THE UPPER LEVEL LOW PRESSURE SYSTEM NOW
OVER THE EASTERN GREAT LAKES WILL ALSO LOOSEN ITS GRIP ON SE MI AS
IT SLOWLY LIFTS OFF TO THE NORTHEAST. THE MID LEVEL CLOUD SHIELD
WILL BE SLOW TO LIFT OFF TO THE EAST AS WARMING ALOFT DEVELOPS A
HIGH BASED INVERSION...WHICH MAY SUSTAIN SOME CLOUDS BASED
BETWEEN 5K AND 7K FT INTO DAYBREAK. THE SFC GRADIENT WILL RELAX
DURING THE NIGHT. SOME WEAK LOW LEVEL DRY AIR ADVECTION AND THE
POTENTIAL CLOUD COVER WILL BE TWO LIMITING FACTORS FOR FOG
FORMATION. GIVEN THE SATURATED SOILS HOWEVER...A BRIEF MENTION OF
SOME MVFR VSBYS IN FOG AROUND DAYBREAK SEEMS REASONABLE AT THIS
TIME. IF CLEARING IS MORE EXTENSIVE THAN EXPECTED...FOG WILL BE A
MUCH BIGGER CONCERN SUNDAY MORNING.
FOR DTW...UPSTREAM OBSERVATIONS SUGGEST THE W-NW FLOW HAS ADVECTED ENOUGH
LOW LEVEL DRY AIR ACROSS THE I-94 CORRIDOR TO LIFT CEILINGS ABOVE
5K FT. EXPECT THE CEILINGS WILL REMAIN ABOVE 5000 FT THROUGH THE
NIGHT.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE ON POTENTIAL FOR CEILINGS BELOW 5000 FT TO
REDEVELOP SUNDAY AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 340 PM EDT SAT AUG 11 2012
SHORT TERM...THIS EVENING AND TONIGHT
THE CLOSED CIRCULATION OF THE BAROTROPIC UPPER LEVEL PRESSURE SYSTEM
REMAINS CENTERED OVER PORTIONS OF FAR SOUTHWESTERN ONTARIO THIS
AFTERNOON. THIS POSITIONING FOR THE PAST 6HRS SEEMS TO HAVE BEEN A
RESULT OF A LAKE AGGREGATE EFFECT OFF OF THE CENTROID OF THE CENTRAL
GREAT LAKES. THE EFFECTIVE REACH OF THE LOW HAS BEEN GREAT ENOUGH TO
KEEP THE ENTIRETY OF EASTERN LOWER MICHIGAN UNDER A VEIL OF LOW TO
MIDLEVEL STRATUS. EROSION OF THE WESTERN EDGE OF THE CLOUDS IS
TAKING PLACE AS WE/RE CURRENTLY SEEING SOME CELLULAR BASED CLOUD
SCALE CIRCULATIONS/SUBSIDENCE BRINGING SOME INCREASED SUNSHINE AT
THE WESTERN CWA DOORSTEP. EVEN IF THIS OCCURS...TIME IS RUNNING OUT
TO SALVAGE MUCH IF ANY OF THE TODAY PERIOD. MAY SEE A 3-5 DEGREE
SPIKE IF THAT OCCURS...MERELY PUTTING US AT THE FORECASTED HIGH
VALUES FOR TODAY.
SUBTLE TROUGH AXIS WILL PUSH TO THE LAKE ERIE APPENDAGE PRIOR TO
00Z. THIS WILL OFFER ADDITIONAL SUPPORT FOR A CONTINUATION OF THE
GRADIENT FLOW RIGHT UP TO THE ADVENT OF THE EVENING ALONG WITH THE
SUBSEQUENT EVAPORATION/DRYING OF THE LOW LEVEL TROPOSPHERE.
SOUTHEASTERN MICHIGAN WILL RESIDE IN A GENERAL AREA OF DIFFERENTIAL
AVA THROUGH THE EVENING HOURS PER RAP-FORMERLY RUC. THIS RAP DATASET
ALSO SEEMS TO HAVE A REASONABLE HANDLE OF THE CYCLONIC VORTICITY
FILAMENT NOW EXITING THE FAR EAST. THUS...FOR THE REMAINDER OF THE
AFTERNOON/EARLY EVENING WILL BE LOOKING AT POTENTIAL FOR SMALLISH
WAVES OF LIGHT SHOWERS/DRIZZLE BUT NOT ANTICIPATING MUCH IN THE WAY
OF WIDESPREAD HEAVY PRECIPITATION. LOSS OF INSOLATION THIS EVENING
SHOULD SHUT EVERYTHING DOWN WITH TIME. ELEVATED LEVELS OF NEAR
SURFACE MOISTURE BRINGS PROSPECTS OF FOG TOWARDS MORNING ESPECIALLY
IF CLOUD COVER TOTALLY DISSIPATES. NOT SEEING A GREAT MODELED
MOISTURE PROFILE FOR FOG TONIGHT AND WILL LEAVE PATCHY MENTION IN
THE GRIDS...BEST POTENTIAL SHOULD BE IN LOW LYING AREAS. LACK OF
ADVECTION WILL LIKELY KEEP LOWS IN THE MIDDLE TO UPPER 50S.
LONG TERM...SUNDAY THROUGH SATURDAY
ACTIVE WEATHER PATTERN WILL CONTINUE DURING THE UPCOMING WEEK WITH
TWO MAJOR SYSTEM SLATED TO TRAVEL THROUGH THE GREAT LAKES...BOTH
BRINGING THE CHANCE OF WIDESPREAD RAINFALL. THESE SYSTEMS WILL BE
TRACKING INTO THE AREA WITHIN MEAN NORTHWEST UPPER FLOW...WITH THIS
PATTERN ESSENTIALLY KEEPING TEMPERATURES NEAR AVERAGE FOR WARMEST
DAYS IMMEDIATELY PRECEDING THESE STORM SYSTEMS AS SHORTWAVE RIDGING
TRANSLATES THROUGH THE AREA TO BELOW AVERAGE AFTER IN THE WAKE OF
THESE SYSTEMS AS COLD AIR ADVECTION AND RESIDUAL MOISTURE AND CLOUD
COVER HOLDS TEMPERATURES DOWN. THE COOLEST AIRMASS WILL HOLD OFF
UNTIL LATE IN THE FORECAST PERIOD AS SECOND SHORTWAVE TAPS A FAIR
AMOUNT OF FALL-LIKE AIR AS IT DROPS ACROSS CANADA INTO THE LAKES
REGION.
THE FIRST SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY CHURNING EAST
ACROSS THE US ROCKIES NEAR THE MONTANA AND WYOMING STATE LINE. ITS
COUNTERPART IS ANOTHER SHORTWAVE WHICH IS TRACKING OVER THE CANADIAN
ROCKIES. BOTH VORTICITY CENTERS ARE QUITE WELL DEVELOPED ALREADY.
THE POSITIONING OF THE SOUTHERN SHORTWAVE WILL FAVOR AN EVENTUAL
TRACK OF THE MAIN ENERGY ACROSS THE NORTHERN OHIO VALLEY/SOUTHERN
GREAT LAKES...WHICH WILL BE FAVORABLE FOR A FAIRLY WIDESPREAD AND
STEADY RAIN ACROSS THE AREA. MODELS HAVE REMAINED RATHER CONSISTENT
RUN TO RUN AS WELL AS IN RESPECT TO EACH OTHER IN BRINGING THIS
STORM SYSTEM INTO THE AREA LATE MONDAY...HAVING THE BULK OF THE
RESULTING PRECIPITATION EVENT OCCUR MONDAY NIGHT...AND THEN HOLDING
ONTO LINGERING SHOWERS INTO TUESDAY. WILL NOT ADJUST FORECAST MUCH
OTHER THAN TO INCREASE PRECIPITATION CHANCES SLIGHTLY AS CONFIDENCE
IN THIS SCENARIO CONTINUES TO INCREASE.
THE SECOND SYSTEM...STILL WELL OFF THE CANADIAN WEST COAST...WILL
EVENTUALLY COME ONSHORE OVER BRITISH COLUMBIA AND TAP A LARGER CHUNK
OF COLDER AIR AS THE NORTHERN STREAM COMPONENT OF THE JET ENERGY
REMAINS DOMINANT AS IT CROSS NOAM. THIS WILL RESULT IN A SURFACE LOW
TRACKING THROUGH SOUTHERN CANADA AND JUST BRUSHING THE NORTHERN
GREAT LAKES. THIS LOW WILL FORCE A STRONG COLD FRONT THROUGH THE
GREAT LAKES AS IT WRAPS UP INTO THE JAMES BAY/HUDSON BAY AREA. THE
TIMING IS SLIGHTLY MORE ELUSIVE...BUT FOR A DAY 6/7 FORECAST...THE
CONFIDENCE REMAINS HIGHER THAN NORMAL AS MODELS SUGGEST A THURSDAY
NIGHT INTO FRIDAY TIME FRAME. THIS SCENARIO...WITH THE MAIN SYSTEM
NORTH OF THE REGION...SUPPORTS A LINE OR LINES OF CONVECTION IN
ADVANCE OR WITH THE COLD FRONTAL PASSAGE...FOLLOWED BY WRAPAROUND
MOISTURE AND EVEN SOME LAKE EFFECT/ENHANCED SHOWER ACTIVITY HEADING
INTO THE WEEKEND AS THE COOLER AIR INTERACTS WITH RELATIVELY WARM
LAKE WATERS. SO...OVERALL...WHILE RAIN CHANCES LOOK PRETTY GOOD AT
THIS POINT...THIS ACTIVITY WILL BE SHORTER LIVED AND MORE SCATTERED
IN NATURE THAN THE SYSTEM EARLY IN THE WEEK.
AS ELUDED TO EARLIER...TEMPERATURES WILL OSCILLATE BETWEEN AVERAGE
AND BELOW AVERAGE WITH THE APPROACH AND THEN DEPARTURE OF THESE
STORM SYSTEMS. THIS WILL BRING HIGH TEMPERATURES AROUND 80 EARLY IN
THE WEEK AND AGAIN WEDNESDAY/THURSDAY...WITH HIGHS CLOSER TO 70
TUESDAY AND 70 OR LESS FRIDAY INTO SATURDAY. LOWS WILL RANGE IN THE
UPPER 50S TO LOWER 60S UNTIL THE LAST PART OF THE FORECAST PERIOD
WHEN LOWS AROUND 50 WILL BE MORE COMMON AS THE COLDER AIRMASS SPILLS
INTO THE AREA. IN FACT...A FEW READINGS IN THE 40S SEEM PROBABLE BY
NEXT WEEKEND IF THE CURRENT BASIC STORM TRACK SCENARIO HOLDS CLOSE
TO CURRENT PROJECTIONS.
MARINE...
THE BROAD LOW PRESSURE CENTER CIRCULATION IS IN PLACE OVER FAR
SOUTHERN LAKE HURON THIS AFTERNOON. OVERALL...THE WEAK SFC LOW
FEATURE HAS KEPT CONDITIONS RELATIVELY IN CHECK GIVEN THE ANOMALOUS
PARENT UPPER LEVEL SYSTEM. THE AREA WATERS ARE EXPERIENCE SOME LOW
STABILITY CONDITIONS WHICH WILL MAINTAIN THE RESIDUAL CHOPPY SEA
STATE THROUGH THE TONIGHT PERIOD. THIS IS HANDLED IN THE NEARSHORE
ZONES WITH SMALL CRAFT ADVISORIES THAT ARE IN EFFECT UNTIL 2Z THIS
EVENING. WAVE HEIGHTS SHOULD TRANSLATE QUICKLY AWAY FROM THE US
WATERS OVERNIGHT...AND THE DECISION WAS MADE TO MAINTAIN THE
INHERITED TIMING OF HEADLINES. BUILDING HIGH PRESSURE WILL BRING
MUCH CALMER CONDITIONS LATE SUNDAY AND SUNDAY NIGHT. AN APPROACHING
TROUGH OF LOW PRESSURE WILL ADVANCE INTO THE GREAT LAKES REGION BY
MONDAY NIGHT...POTENTIALLY SUPPORTING A SURFACE LOW CENTER THAT
WOULD TRACK THROUGH SOUTHEASTERN MICHIGAN ON TUESDAY.
AVAILABLE MODEL GUIDANCE IS NOT VERY STRONG WITH THE LAKE EFFECT
POTENTIAL OF SHOWERS AND TSTORMS OVERNIGHT. WITH THAT SAID...PATTERN
RECOGNITION SUGGESTS CONVECTION WILL BE POSSIBLE THROUGHOUT THE
NIGHT. GIVEN THE STABILITY AND VORTICITY RICH
ENVIRONMENT....WATERSPOUTS WILL BE POSSIBLE WITH ANY ACTIVITY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO PORT SANILAC...UNTIL 10 PM SATURDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
SHORT TERM...CB
LONG TERM....DG
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
414 PM EDT FRI AUG 10 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 410 PM EDT FRI AUG 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER SE
LOWER MI. AN EXTENSIVE PCPN SHIELD PERSISTED ON THE NW FLANK OF THE
LOW ASSOCIATED WITH THE STRONGER 800-700 MB FGEN/DEFORMATION.
TONIGHT...SATELLITE TRENDS AND MODELS KEEP ANY PCPN ASSOCIATED WITH
THE SFC/MID LEVEL LOW EAST OF THE CWA.SFC HIGH PRES RIDGE WILL DRIFT
E TOWARD UPPER MI TONIGHT...BUT ONLY CLOSE ENOUGH FOR JUST THE FAR W
TO SEE LIGHT/CALM WIND AND GOOD RADIATIONAL COOLING CONDITIONS. PWAT
VALUES OVER THE WEST FALL INTO THE 0.30 TO 0.50 INCH RANGE. A
TIGHTER PRES GRADIENT TO THE EAST WILL MAINTAIN STRONG ENOUGH BNDRY
LAYER WINDS TO KEEP TEMPS FROM FALLING OFF AS MUCH. SOME MID OR HIGH
CLOUDS OVER THE E WILL ALSO LIMIT TEMP DROP. GUIDANCE TEMPS WERE
REASONABLE WITH TEMPS FALLING OFF INTO THE LOWER 40S INLAND
WEST...ESPECIALLY IN USUAL COLD SPOTS.
SATURDAY...AS THE LOW LIFTS SLOWLY TO THE NE THROUGH SRN
ONTARIO...NRLY WINDS WILL ONLY GRADUALLY DIMINISH.
WITH 850 MB TEMPS AROUND 9C...MAX READINGS INTO THE LOWER TO MID 70S
ARE EXPECTED. FCST SOUNDINGS AND DEEPER MIXING SHOW POTENTIAL FOR
DEWPOINTS TO DRAMATICALLY(AOB 40)INLAND. SO...ADJUSTED DEWPOINTS
TOWARD LOWER END NAM GUIDANCE WITH AT LEAST LOWER 40S WITH MIN RH
VALUES AOB 35 PCT.
A HIGH RISK OF RIP CURRENTS REMAINS TONIGHT INTO SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 410 PM EDT FRI AUG 10 2012
THE LATE SUMMER PATTERN WILL BE IN FULL SWING THROUGH THE LONG TERM
AS DEEP TROUGHING SLOWLY DEVELOPS OVER EASTERN CANADA. AS A
RESULT...A SIGNIFICANT COOL-DOWN LATE NEXT WEEK IS APPEARING MORE
LIKELY WITH EACH PASSING DAY.
SATURDAY NIGHT THROUGH MONDAY...THE STACKED CLOSED LOW THAT IS
BRINGING HEAVY PRECIPITATION TO PORTIONS OF LOWER MI TODAY WILL
CONTINUE DRIFTING NORTHEAST THROUGH SATURDAY...EVENTUALLY REACHING
GEORGIAN BAY BY 00Z SUNDAY. BOTH THE NAM AND GFS CONTINUE TO
INDICATE AN ENHANCED BAND OF H7 DEFORMATION PUSHING NW INTO FAR
EASTERN UPPER MI...WITH THE NAM BEING THE MOST AGGRESSIVE. BUT GIVEN
THAT THE NAM HAS OVERDONE MOISTURE WITH THIS SYSTEM AND THAT THERE
WILL BE SIGNIFICANT DRY AIR IN PLACE ABOVE 800 MB...DO NOT THINK ANY
PRECIP WILL MAKE IT INTO THE CWA.
A BRIEF SHORTWAVE RIDGE WILL THEN MOVE ACROSS THE AREA LATE SATURDAY
NIGHT INTO SUNDAY AND BRING MOSTLY CLEAR SKIES. SOME HIGH CLOUDS MAY
REMAIN OVER THE EAST HALF AS A RESULT OF THE LEFT ENTRANCE TO A WEAK
UPPER JET ON THE BACKSIDE OF THE DEPARTING MID-LEVEL LOW. TEMPS
COULD FALL A DECENT AMOUNT ACROSS THE INTERIOR WEST HALF WITH LIGHT
WINDS...VERY DRY AIR...AND MINIMAL CLOUD COVER. HAVE DROPPED TEMPS
INTO THE LOWER FOR SOME OF THE NORMAL COLD SPOTS.
AS MENTIONED IN THE PREVIOUS FORECAST...IT APPEARS A CONVECTIVELY
INDUCED SHORTWAVE WILL DEVELOP SATURDAY NIGHT ACROSS THE NORTHERN
PLAINS. THIS WAVE IS PROGGED TO ERODE THE RIDGE AND MOVE SOUTHEAST
INTO SOUTHERN MN/NORTHERN IA BY 00Z MONDAY. MEANWHILE...A LARGER
MID-LEVEL TROUGH OVER NORTHERN SASKATCHEWAN AT 00Z SUNDAY WILL MOVE
TO THE EAST THROUGH THE WEEKEND...REACHING FAR NORTHERN QUEBEC BY
18Z MONDAY. AN EXTENSION OF THIS TROUGH AND AN ASSOCIATED COLD FRONT
SHOULD TRACK ACROSS THE CWA MONDAY AS IT PICKS UP THE SHORTWAVE IN
THE UPPER MISSISSIPPI VALLEY. THE ECMWF HAS TRENDED MUCH FASTER
WITH THE TROUGH OVER THE PAST FEW RUNS...WHILE THE GFS HAS ACTUALLY
SLOWED THE TROUGH. FOR NOW...WILL STICK WITH THE IDEA THAT IT WILL
COME THROUGH SOMETIME ON MONDAY...BEGINNING WITH THE WEST IN THE
MORNING AND ENDING WITH THE EAST IN THE LATE AFTERNOON. THE TROUGH
WILL BE STARVED OF LOW-LEVEL MOISTURE AS THE CONVECTIVE COMPLEX TO
THE SOUTH SHOULD PREVENT MOST NORTHWARD FLOW OF MOISTURE. SOME
SUNSHINE WILL MAKE IT THROUGH THE CLOUDS...ALLOWING SBCAPE VALUES TO
REACH A FEW HUNDRED J/KG. EXTRA LIFTING SUPPORT FROM WEAK LAKE
BREEZES WILL LIKELY ALLOW SOME ISOLATED TO SCATTERED SHOWERS AND A
FEW THUNDERSTORMS TO DEVELOP INLAND...MAINLY IN THE AFTERNOON. THIS
ACTIVITY WILL SPREAD EASTWARD ALONG THE FRONT BEFORE CLEARING OUT
EARLY MONDAY EVENING.
DEW POINTS WILL BE A CONCERN ON SUNDAY WITH ABUNDANT SUNSHINE AND A
SHARP TRANSITION TO DRY AIR ABOVE THE MIXED LAYER. FORECAST H8 DEW
POINTS ARE AROUND 8C...BUT QUICKLY DROP TO -10 TO -20C BY H7. WINDS
WILL BE LIGHT THOUGH...SO DECENT ENTRAINMENT OF THE DRY AIR MAY BE
LIMITED. WILL LOWER DEW POINTS TO THE UPPER 40S INTERIOR WEST IN
THE AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...A MID-LEVEL RIDGE WILL BEGIN TO
BUILD IN FROM THE WEST MONDAY NIGHT AND BRING MOSTLY CLEAR SKIES
THROUGH WEDNESDAY. POPS WERE REMOVED WEDNESDAY AS THE ECMWF...WHICH
HAD POPS IN THE FORECAST YESTERDAY...HAS LINED UP WITH THE GFS IN
SHARPENING THE RIDGE AND KEEPING THE AREA DRY.
MORE ABUNDANT MIXING DAYS COULD BE IN STORE TUESDAY AND WEDNESDAY AS
VERY DRY AIR REMAINS ABOVE THE MIXED LAYER. WEDNESDAY WILL BE OF
MORE CONCERN AS TEMPERATURES WILL RISE TO AROUND 80 AND DEW POINTS
WILL POSSIBLY FALL WELL INTO THE 50S. AS OF NOW...FORECAST MIN RH
VALUES WILL BE IN THE LOW 40S FOR THE INTERIOR WEST.
HOWEVER...MIXING MAY BE EVEN MORE AGGRESSIVE THAN CURRENTLY
FORECAST...SO RH VALUES MAY FALL INTO THE 30S. WINDS WILL REMAIN
RATHER LIGHT...LESS THAN 15 MPH...SO FIRE WX CONCERNS ARE LIMITED
RIGHT NOW.
WEDNESDAY NIGHT AND FRIDAY...A SIGNIFICANT CHANGE IN THE WEATHER
PATTERN APPEARS TO BE IN THE MAKING WEDNESDAY NIGHT. A SHORTWAVE
TROUGH CURRENTLY OVER THE GULF OF ALASKA WILL MOVE EAST THROUGH THE
SOUTHERN CANADIAN PROVINCES THROUGH THE WEEKEND WHILE PICKING UP
ENERGY AND MUCH COOLER H8 AIR FROM A POLAR VORTEX WEST OF GREENLAND.
GUIDANCE IS RATHER CONSISTENT WITH THE HANDLING OF THIS TROUGH
THROUGH WEDNESDAY NIGHT...BUT SOLUTIONS BEGIN TO DIVERGE BY
THURSDAY. THE ECMWF AND GEM BRING THE TROUGH NORTHEASTWARD MUCH
QUICKER THAN THE GFS. THE ECMWF THEN TRIES TO DEVELOP A CLOSED LOW
OVER THE CWA ON FRIDAY...RESULTING IN PLENTY OF RAIN. SOLUTIONS ARE
MUCH TOO INCONSISTENT AND DIVERGENT AT THIS POINT TO MAKE ANY SENSE
OF TIMING AND PRECIP...BUT ALL STILL HINT AT A MUCH COOLER END TO
THE WEEK...WITH HIGHS POSSIBLY AROUND 60 IN SOME PLACES ON FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 159 PM EDT FRI AUG 10 2012
MVFR CEILINGS AT KSAW WITH UPSLOPE WINDS WILL GIVE WAY TO VFR
CONDITONS DURING THE AFTERNOON WHEN BNDRY LAYER DRYING BECOMES MORE
SIGNIFICANT. OTHERWISE...VFR CONDITIONS WILL PREVAIL FOR THE REST OF
THE FCST PERIOD. WINDS WILL BE GUSTY TODAY...ESPECIALLY AT KSAW WHERE
GUSTS TO AROUND 25KT ARE EXPECTED DUE TO FAVORABLE WIND DIRECTION
AND CLOSER PROXIMITY TO DEPARTING SYSTEM.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EDT FRI AUG 10 2012
EXPECT THE STRONGEST WINDS DURING THE FCST PERIOD TO OCCUR TONIGHT
THROUGH SAT UNDER RELATIVELY TIGHT PRES GRADIENT BTWN LOW PRES DRIFTING
NNE INTO SRN ONTARIO AND HIGH PRES DRIFTING E TOWARD THE UPPER
LAKES. CLOSER TO APPROACHING HIGH...WINDS WILL BE LIGHTEST OVER WRN
LAKE SUPERIOR... GENERALLY 10-20KT. OVER THE E...NNE WINDS WILL BE
MOSTLY IN THE 15-25KT RANGE. WINDS WILL SLOWLY DIMINISH TONIGHT INTO
SAT...BUT WINDS WILL REMAIN AOA 20 KT OVER ERN LAKE SUPERIOR TIL LATE
SAT. WINDS SUN THRU TUE 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 INTO FRIDAY COULD BRING
STRONGER NW WINDS INTO THE 20-30 KT RANGE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TK
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
955 PM CDT SAT AUG 11 2012
.EVENING FORECAST UPDATE...
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.../00Z TAF ISSUANCE/
MAIN FORECAST CONCERNS ARE THE EXTENT OF CLOUDS AND PRECIP
ASSOCIATED WITH THE AREA OF LOW PRESSURE MOVING FROM THE PLAINS
TOWARD THE LOWER GREAT LAKES DURING THE PERIOD. THE 700MB REFLECTION
OF THE LOW IS FORECAST TO TRACK FROM THE DAKOTAS ACROSS SOUTHERN
MN BETWEEN 06Z SUNDAY AND 06Z MONDAY. CONTINUE TO FAVOR THE NAM
AND HI-RES ARW-EAST SOLUTIONS...WHICH INDICATE KAXN-KMSP WILL BE
ON THE NORTHERN EDGE OF THE RAIN SHIELD. KRWF IS EXPECTED TO HAVE
THE LONGEST DURATION OF RAIN SHOWERS...WITH PRECIP LIKELY
DEVELOPING PRIOR TO DAYBREAK SUNDAY...AND CONTINUING THROUGH MUCH
OF THE DAY. LLVL RH PROGS ON THE MAJORITY OF MODEL SOLUTIONS
INDICATE THE POTENTIAL FOR MVFR CIGS ATTENDANT WITH THE LOW...SO
HAVE INCLUDED THAT AT MN TAF SITES. NO THUNDER IS EXPECTED AT THE
TAF SITES WITH THIS SYSTEM...EXCEPT FOR POSSIBLY AT KRWF.
MSP...HIGH CLOUDS WILL THICKEN AND LOWER TONIGHT THROUGH SUNDAY
MORNING. MAINTAINING A 6SM -SHRA MENTION BETWEEN 18Z SUN AND 00Z
MONDAY. COULD SEE A PERIOD OF MVFR CIGS CIRCA 2500 FT ON SUNDAY
AFTERNOON AS THE TROUGH MOVES ACROSS. WINDS 7 KT OR LESS
THROUGHOUT THE PERIOD...MAINLY FROM THE SOUTHEAST TONIGHT AND
EAST/NORTHEAST SUNDAY.
OUTLOOK...
SUNDAY NIGHT...VFR-MVFR WITH SHRA AND ISOLD TSRA POSSIBLE...AT
KRWF. VARIABLE WINDS 5 KTS.
MONDAY...VFR. NW WINDS 5-10 KTS.
TUESDAY...VFR. VARIABLE WINDS 5 KTS.
WEDNESDAY...VFR...ISOLD TSRA IN THE AFTERNOON. S WINDS 10-15 KTS.
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/CLF/LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
702 PM CDT SAT AUG 11 2012
.UPDATE...FOR THE 00Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 132 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.../00Z TAF ISSUANCE/
MAIN FORECAST CONCERNS ARE THE EXTENT OF CLOUDS AND PRECIP
ASSOCIATED WITH THE AREA OF LOW PRESSURE MOVING FROM THE PLAINS
TOWARD THE LOWER GREAT LAKES DURING THE PERIOD. THE 700MB REFLECTION
OF THE LOW IS FORECAST TO TRACK FROM THE DAKOTAS ACROSS SOUTHERN
MN BETWEEN 06Z SUNDAY AND 06Z MONDAY. CONTINUE TO FAVOR THE NAM
AND HI-RES ARW-EAST SOLUTIONS...WHICH INDICATE KAXN-KMSP WILL BE
ON THE NORTHERN EDGE OF THE RAIN SHIELD. KRWF IS EXPECTED TO HAVE
THE LONGEST DURATION OF RAIN SHOWERS...WITH PRECIP LIKELY
DEVELOPING PRIOR TO DAYBREAK SUNDAY...AND CONTINUING THROUGH MUCH
OF THE DAY. LLVL RH PROGS ON THE MAJORITY OF MODEL SOLUTIONS
INDICATE THE POTENTIAL FOR MVFR CIGS ATTENDANT WITH THE LOW...SO
HAVE INCLUDED THAT AT MN TAF SITES. NO THUNDER IS EXPECTED AT THE
TAF SITES WITH THIS SYSTEM...EXCEPT FOR POSSIBLY AT KRWF.
MSP...HIGH CLOUDS WILL THICKEN AND LOWER TONIGHT THROUGH SUNDAY
MORNING. MAINTAINING A 6SM -SHRA MENTION BETWEEN 18Z SUN AND 00Z
MONDAY. COULD SEE A PERIOD OF MVFR CIGS CIRCA 2500 FT ON SUNDAY
AFTERNOON AS THE TROUGH MOVES ACROSS. WINDS 7 KT OR LESS
THROUGHOUT THE PERIOD...MAINLY FROM THE SOUTHEAST TONIGHT AND
EAST/NORTHEAST SUNDAY.
OUTLOOK...
SUNDAY NIGHT...VFR-MVFR WITH SHRA AND ISOLD TSRA POSSIBLE...AT
KRWF. VARIABLE WINDS 5 KTS.
MONDAY...VFR. NW WINDS 5-10 KTS.
TUESDAY...VFR. VARIABLE WINDS 5 KTS.
WEDNESDAY...VFR...ISOLD TSRA IN THE AFTERNOON. S WINDS 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LRS/CLF
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
855 PM MDT SAT AUG 11 2012
.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 2330Z.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. SCATTERED CLOUDS
THIS EVENING WILL DIMINISH WITH THE EXCEPTION OF NEAR THE CANADIAN
BORDER...WHERE CLOUDS WILL LINGER. A FEW CLOUDS WILL REDEVELOP ON
SUNDAY AND POSSIBLY A FEW THUNDERSTORMS. COVERAGE OF STORMS LOOKS
TO BE VERY ISOLATED AT THIS TIME...THEREFORE WILL NOT MENTION
THUNDER IN THE TAFS. 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
612 PM CDT SAT AUG 11 2012
.AVIATION...00Z TAF. ISOLATED SHOWERS AND A HIT OR MISS STRIKE OF
THUNDER HAS MOVED EAST OF THE TERMINAL EARLY THIS EVENING...WHILE
LIMITED CONVECTION LINGERS IN WESTERN NEBRASKA AND KANSAS. ANOTHER
ROUND OF CONVECTION IS EXPECTED TO DEVELOP TONIGHT AS AN UPPER
LEVEL DISTURBANCE CROSSES THE PLAINS. HAVE INCLUDED PCPN CHCS FROM
LATE EVENING INTO THE OVERNIGHT HOURS. CLOUD HEIGHTS ARE EXPECTED
TO REMAIN AT VFR LEVELS FOR THE MOST PART ALTHOUGH AN OUTSIDE MVFR
CIG IS NOT OUT OF THE QUESTION FOR A BRIEF PERIOD OF TIME. WINDS
WILL SHIFT NORTHWESTERLY HEADING TOWARDS SUNDAY MORNING FOLLOWING
THE PASSAGE OF A COLD FRONTAL BOUNDARY. BY MIDDAY
SUNDAY...NORTHWEST WIND GUSTS IN EXCESS OF 20KTS ARE POSSIBLE.
&&
.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.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1132 PM CDT THU AUG 9 2012
.AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. LIGHT NORTHEAST
WINDS WILL CONTINUE OVERNIGHT WITH CLEAR SKIES. COULD BE SOME
MVFR FOG AT KOMA/KOFK FROM ABOUT 10-14Z. NORTHEAST WINDS AROUND
8KTS AFTER THAT THROUGH THE REMAINDER OF FRIDAY WITH CUMULUS
CLOUDS DEVELOPING AGAIN AROUND 5000 FEET BY LATE MORNING THROUGH
THE AFTERNOON.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 305 PM CDT THU AUG 9 2012/
DISCUSSION...
TEMPERATURES WILL PROVIDE THE PRIMARY FORECAST CHALLENGES THROUGH
FRIDAY NIGHT...THEN ATTENTION SHIFTS MORE TOWARD PRECIPITATION
CHANCES OVER THE WEEKEND.
MAIN FEATURES FROM THE 12Z UPPER AIR CHARTS THIS MORNING SHOWED THE
FOLLOWING. AT 300 MB...JETSTREAM CURVED NORTHEAST ACROSS THE PACIFIC
NORTHWEST INTO THE NORTHERN PLAINS...THEN TURNED SOUTHEAST INTO THE
OHIO VALLEY. A JET MAX OF AROUND 100 KNOTS WAS NOTED OVER MINNESOTA.
AT 500 MB...A RATHER IMPRESSIVE CLOSED LOW WAS OVER NORTHEAST
MINNESOTA WITH 12 HOUR HEIGHT FALLS OF 70 METERS NOTED AT KINL. THE
CENTER OF A MID LEVEL RIDGE WAS OVER THE FOUR CORNERS REGION.
COOLER AIR WAS PUSHING DOWN FROM MINNESOTA AND THE EASTERN DAKOTAS
AT 700 MB AND 850 MB.
SURFACE ANALYSIS EARLY THIS AFTERNOON INDICATED A RIDGE OF COOL HIGH
PRESSURE EXTENDING FROM ONTARIO AND MANITOBA DOWN INTO THE NORTHERN
AND WESTERN PLAINS. WINDS WERE MAINLY FROM THE NORTH OVER THE LOCAL
AREA. THAT SURFACE RIDGE WILL BUILD EASTWARD ACROSS THE FORECAST
AREA TONIGHT THROUGH FRIDAY NIGHT...WITH SEASONABLE TEMPERATURES AND
DRY CONDITIONS. EXPECT SOME PATCHY FOG TONIGHT AS WINDS DECREASE...
ESPECIALLY IN PARTS OF OUR CENTRAL AND EASTERN ZONES WHERE SPOTTY
RAIN FELL YESTERDAY AND TUESDAY. EXPECT THAT TO BURN OFF QUICKLY
FRIDAY...IF IT DEVELOPS...WITH SCATTERED CUMULUS MOST AREAS BY THE
AFTERNOON. HIGHS FRIDAY WILL BE IN THE 80S...CLOSE TO NAM MOS.
RETURN FLOW STRENGTHENS LATE FRIDAY NIGHT INTO SATURDAY AND
MODELS ARE IN GENERAL AGREEMENT WITH LARGE SCALE PATTERN. THEY
SHOW SOME 850-700 MB THETA E ADVECTION SPREADING FROM WEST TO EAST
ON SATURDAY. LARGE SCALE FORCING SEEMS WEAK AT BEST...SO KEPT POPS
ONLY AT 20 PERCENT AND TRIED TO CONFINE THOSE TO NORTHEAST
NEBRASKA SATURDAY. A MODEST SHORTWAVE TROUGH DOES MOVE ACROSS THE
PLAINS FOR SATURDAY NIGHT/EARLY SUNDAY...AND THIS IS PROBABLY OUR
BEST CHANCE FOR THUNDERSTORMS. THE 12Z GFS SEEMED WAY TOO GENEROUS
WITH QPF AND ITS OUTPUT WAS GENERALLY NOT USED. FAVORED A BLEND OF
THE NAM AND ECMWF FOR NOW...BUT SHOULD BE ABLE TO ADJUST THINGS
MORE AS WE GET CLOSER WITH 4 KM NAM AND HRRR MODELS. LINGERED SOME
LOW POPS INTO SUNDAY BASED ON CURRENT MODEL TIMING OF FORCING.
OTHERWISE...LOOK FOR DEAMPLIFICATION OF THE 500 MB PATTERN THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK AS RIDGE SHIFTS FROM THE FOUR
CORNERS REGION TO THE SOUTHERN PLAINS. AS HEIGHTS INCREASE BY MID
WEEK...HIGHS IN THE 90S WILL BECOME COMMON AGAIN.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1022 PM EDT SAT AUG 11 2012
.SYNOPSIS...
A LARGE UPPER LEVEL STORM SYSTEM WILL CONTINUE TO SPIN OVER
SOUTHEASTERN CANADA FOR THE REMAINDER OF THE WEEKEND. THOUGH
CONDITIONS WILL BE MAINLY DRY SUNDAY...OUR REGION WILL BE ON THE
OUTER EDGE OF THE DEPARTING SYSTEM. THIS WILL KEEP A FAIR AMOUNT
OF CLOUDS AND A CHANCE FOR SHOWERS IN THE FORECAST...ESPECIALLY
IN UPSTATE NEW YORK. HIGH PRESSURE WILL BE OVER THE AREA MONDAY
WITH DRY WEATHER.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
IR IMAGERY SHOWS A SHORT WAVE RIPPLING NORTHEASTWARD THROUGH NY
AND PA AT THIS TIME WHICH WAS ENHANCING SHOWERS IN NJ AND SERN PA.
THE 22Z RUN OF THE HRRR BROUGHT THIS NRN EDGE OF THIS PRECIP
SHIELD WELL INTO NE PA AND THE CATSKILLS BY 6Z. THE LATEST 23Z RUN
HAS BACKED OFF BUT LOOKING AT RADAR TRENDS WILL BRING CHC POPS FOR
SHRA INTO FAR ERN PIKE AND SRN SULLIVAN CO/S ARND 6Z...THEN WIND
THEM DOWN TWD 12Z AS THE WAVE PROGRESSES BY. MEANWHILE REST OF
FORECAST AREA WILL SEE A BATCH OF HIGHER CLDS FROM THIS WAVE
ADVECT TO THE NE OVRHD WHILE SOME LOWER COLD AIR SC/ST CONTS TO
FLOW NORTHEASTWARD TWD C NY AND NE PA. THESE CLDS WERE TRACKING
TO NE BUT WERE ERODING AS THEY MOVED OVER THE HIGHER TERRAIN OF
THE ALLEGHENIES OF WRN NY AND NW PA. SO FOR OVRNGT HAVE MAINLY PC
TO MC SKIES. PRECIP ASSCTD WITH THE UPR LVL LOW OVR SRN ONT WILL
STAY W OF THE REGION BEFORE 12Z.
FOR SUNDAY...UPR LVL LOW WILL TRACK NORTH INTO QUE AND PUSH AN UPR
LVL TROF AXIS ACRS C NY AND NE PA DURG THE DAY. THERE WAS A PRETTY
DECENT LOOKING UPR LVL PV LOBE COINCIDENT WITH THE TROF SUGGESTING
SOME LARGE SCALE UPPER LEVEL FORCING AND COOLING ALOFT. MODEL
TEMPERATURES FIELDS REFLECT THIS WITH COOLER AIR AT MID LEVELS.
THE AIR WILL BE COOLER ALOFT FARTHER NORTH SO CHC/S FOR SHRA WILL
BE HIGHER IN NC NY VS NE PA WITH THE DAYTIME HEATING. CAPES WILL
BE MINIMAL SO I EXPECT JUST SHRA. IN ADDTN...DEWPOINTS WILL BE
HIGHER CLOSER TO THE LAKE ONTARIO PLAIN WHERE MOISTURE FROM THE
LAKES GETS INTO THE ACT RAISING DWPTS SOME. SO HAVE HIGHER POPS
NRN CWA...AND LOWER POPS FARTHER SOUTH. BASICALLY CHC POPS C NY
DOWN TO SLGHT CHC IN NE PA...POPS PEAKING IN AFTERNOON.
FOR SUNDAY...LINGERING SHRA WILL LAST THE LONGEST IN NC NY...WITH
SKIES CLEARING TO THE SOUTH AS A SHRT WAVE RDG AXIS TRACKS OVHD.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
UPDATE 330 PM...
SUNDAY WE WILL BE UNDER THE UPPER LEVEL TROF. SUNSHINE WILL CAUSE
LOW LEVEL INSTABILITY BUT MID LEVEL WARM AIR WILL INHIBIT DEEP
CONVECTION. SCATTERED TO ISOLATED SHOWERS IN NY AND THE NRN TIER
OF NE PA MAINLY IN THE AFTN. ALSO A THUNDERSTORM POSSIBLE IN THE
AFTN MOST LIKELY IN THE FINGER LAKES. SHOWERS WANE QUICKLY IN THE
EVENING AS THE TROF LIFTS OUT AND THE A SFC HIGH BUILDS IN.
THE HIGH WILL LAST THROUGH MONDAY INTO MONDAY NIGHT. MONDAY NIGHT
SHOULD BE DRY BEFORE THE NEXT UPPER LEVEL TROF AND SFC LOW MOVES
EAST FROM THE WESTERN GREAT LAKES. A DEEP SOUTHERLY FLOW WILL
BRING WARM AND MOIST AIR INTO THE REGION MONDAY NIGHT AND TUESDAY.
THE TIMING OF THIS SYSTEM IS GOOD BEING LATE IN THE DAY WITH A
STRONG COLD FRONT. A WARM FRONT WILL BRING SHOWERS IN THE
MORNING. CWA SHOULD BE IN THE WARM SECTOR IN THE AFTN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT WITH THE LARGE SCALE
FEATURES THROUGH THE EXTENDED PERIOD BUT SIGNIFICANT TIMING
DIFFERENCES EXISTS WITH SURFACE AND FRONTAL FEATURES. INITIALLY A
BROAD UPPER LEVEL TROF WILL BE OVER THE NORTHEAST WITH A SURFACE
LOW AND MID LEVEL SHORT WAVE MOVING THROUGH THE AREA TUESDAY NIGHT
INTO WEDNESDAY. WILL CONTINUE WITH CHC POPS THROUGH THE PERIOD
FOR SHOWERS ALONG WITH A SLIGHT CHC FOR TSRA. BRIEF UPPER LEVEL
RIDGING AND SFC HIGH PRES WILL PROVIDE DRY WEATHER WEDNESDAY NIGHT
THROUGH MUCH OF THURSDAY NIGHT. NEXT COLD FRONT AND DEEPENING
UPPER LEVEL TROF WILL AFFECT THE REGION LATE IN THE PERIOD WITH
THE GFS MUCH FASTER THAN THE ECMWF. WENT WITH HPC GUIDANCE WHICH
LEANS TOWARD THE SLOWER ECMWF SOLUTION. INCLUDED CHC POPS
FRIDAY/FRIDAY NIGHT FOR SFC LOW AND TRAILING COLD FRONT FOLLOWED
BY CHC POPS ON SATURDAY AS UPPER LEVEL TROF DEEPENS OVER THE
NORTHEAST.
TEMPS THROUGH THE PERIOD WILL BE NEAR SEASONAL LEVELS, EXCEPT FOR
THURSDAY WHICH WILL BE SEVERAL DEGREES ABOVE NORMAL.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
00Z TAF UPDATE...
UPPER LEVEL LOW OVER THE ONTARIO PENINSULA...WILL GRADUALLY LIFT
NORTH-NORTHEAST INTO WESTERN QUEBEC DURING THIS TAF PERIOD. OUR
AREA HAS BEEN IN THE DRY SLOT UP TO THIS EVENING...BUT THE SHIELD
OF MOISTURE WRAPPING AROUND THE LOW...WILL SHIFT OVER THE
TERMINALS LATE TONIGHT INTO SUNDAY MORNING...YIELDING MVFR TO LOW
END VFR CLOUD DECK. ISOLATED TO SCATTERED INSTABILITY SHOWERS WILL
ALSO POP UP SUNDAY AFTERNOON FOR UPSTATE NY TERMINALS...WHICH
COULD RESULT IN BRIEF MVFR FLUCTUATIONS. CLOSER TO THE DEPARTING
UPPER LOW...AN ISOLATED LIGHTNING STRIKE IS NOT OUT OF THE
QUESTION FOR KSYR-KRME CORRIDOR SUNDAY AFTERNOON. LIGHT WINDS OVERNIGHT
BECOMING WSW ON SUNDAY WITH GUSTS TO 10-15 KTS.
OUTLOOK...
SUN NGT-MON NGT...MAINLY VFR.
TUE-WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-THU...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY THU MRNG.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP/DJN
NEAR TERM...DJN
SHORT TERM...TAC
LONG TERM...RRM
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
752 PM EDT SAT AUG 11 2012
.SYNOPSIS...
A LARGE UPPER LEVEL STORM SYSTEM WILL CONTINUE TO SPIN OVER
SOUTHEASTERN CANADA FOR THE REMAINDER OF THE WEEKEND. THOUGH
CONDITIONS WILL BE MAINLY DRY SUNDAY...OUR REGION WILL BE ON THE
OUTER EDGE OF THE DEPARTING SYSTEM. THIS WILL KEEP A FAIR AMOUNT
OF CLOUDS AND A CHANCE FOR ISOLATED SHOWERS IN THE
FORECAST...ESPECIALLY IN UPSTATE NEW YORK. HIGH PRESSURE WILL BE
OVER THE AREA MONDAY WITH DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDATE 700 PM...DRY SLOT CONTINUES OVER HEART OF THE WFO BINGHAMTON
FORECAST AREA AS DRIER AND COOLER AIR SLOWLY BLEEDS EWRD FROM WRN NY
AND WRN PA. SPC ANALYSIS SHOWS THAT MOST OF THE CAPE HAS NOW
PUSHED E OF C NY INTO ERN NY AS LOW-LEVEL DRY ADVECTION CONTINUES
ON SW FLO. WITH CONTINUED LL DRY ADVECTION AND THE LOSS OF SFC
HEATING THIS EVE...CONVECTIVE ACVTY WILL ADVECT EAST AND DIMINISH.
SO HAVE ISLD POPS INITIALLY IN THE FAR EASTERN PART OF THE
BINGHAMTON FORECAST AREA...MAINLY CATSKILLS...JUST FOR A COUPLE MORE
HOURS...THEN LESS THAN 15 POPS. WEST OF THE BGM CWA THERE WAS A LOWER
STRATUS SHIELD THAT HAS FLOWED UP INTO THE ALLEGHENIES AND WILL
CONTINUE TO ADVECT NORTHEASTWARD TONIGHT TWD C NY AND NE PA.
TEMPERATURES WERE MUCH COOLER UNDER THIS STRATUS SHIELD. QUESTION
IS WHETHER IT WILL BE ABLE TO MAKE IT OVER THE ALLEGHENIES AS
THERE IS DOWNSLOPE FLOW ON SW WINDS. NAM AND RAP MODELS BOTH SHOW
THIS BY ENHANCING RH VALUES ON THE ALLEGENHIES AND DIMINISHING RH
ON THE OTHER SIDE. I BELIEVE WE WILL SEE SCT TO OCNL BKN CLDS INTO
C NY ESP...AND EVEN POTENTIALLY PART OF NE PA SO WILL KEEP GRIDS JUST
IN THE PC RANGE EXCEPT HIGHER TERRAIN OF STEUBEN COUNTY.
TWEEKED MINS...WINDS JUST A TOUCH. OTHERWISE NO SIG CHANGES.
UPDATE 330 PM...IN THE DRY SLOT THIS AFTERNOON OVER MUCH OF THE
CWA. SHOWERS ARE MOVING EAST OF THE AREA AHEAD OF A SLOW MOVING
COLD FRONT. MOST OF THIS WILL BE IN EASTERN NY BY 21Z. IN THE WEST
A SLOW MOVING STACKED LOW OVER SE ONTARIO WILL CONTINUE. THICKER
CLOUDS WILL SLOWLY MOVE INTO THE WESTERN COUNTIES THE REST OF
TODAY AND TONIGHT...AS THE LOW MOVES NORTHEAST INTO QUEBEC SUNDAY.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
UPDATE 330 PM...
SUNDAY WE WILL BE UNDER THE UPPER LEVEL TROF. SUNSHINE WILL CAUSE
LOW LEVEL INSTABILITY BUT MID LEVEL WARM AIR WILL INHIBIT DEEP
CONVECTION. SCATTERED TO ISOLATED SHOWERS IN NY AND THE NRN TIER
OF NE PA MAINLY IN THE AFTN. ALSO A THUNDERSTORM POSSIBLE IN THE
AFTN MOST LIKELY IN THE FINGER LAKES. SHOWERS WANE QUICKLY IN THE
EVENING AS THE TROF LIFTS OUT AND THE A SFC HIGH BUILDS IN.
THE HIGH WILL LAST THROUGH MONDAY INTO MONDAY NIGHT. MONDAY NIGHT
SHOULD BE DRY BEFORE THE NEXT UPPER LEVEL TROF AND SFC LOW MOVES
EAST FROM THE WESTERN GREAT LAKES. A DEEP SOUTHERLY FLOW WILL
BRING WARM AND MOIST AIR INTO THE REGION MONDAY NIGHT AND TUESDAY.
THE TIMING OF THIS SYSTEM IS GOOD BEING LATE IN THE DAY WITH A
STRONG COLD FRONT. A WARM FRONT WILL BRING SHOWERS IN THE
MORNING. CWA SHOULD BE IN THE WARM SECTOR IN THE AFTN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT WITH THE LARGE SCALE
FEATURES THROUGH THE EXTENDED PERIOD BUT SIGNIFICANT TIMING
DIFFERENCES EXISTS WITH SURFACE AND FRONTAL FEATURES. INITIALLY A
BROAD UPPER LEVEL TROF WILL BE OVER THE NORTHEAST WITH A SURFACE
LOW AND MID LEVEL SHORT WAVE MOVING THROUGH THE AREA TUESDAY NIGHT
INTO WEDNESDAY. WILL CONTINUE WITH CHC POPS THROUGH THE PERIOD
FOR SHOWERS ALONG WITH A SLIGHT CHC FOR TSRA. BRIEF UPPER LEVEL
RIDGING AND SFC HIGH PRES WILL PROVIDE DRY WEATHER WEDNESDAY NIGHT
THROUGH MUCH OF THURSDAY NIGHT. NEXT COLD FRONT AND DEEPENING
UPPER LEVEL TROF WILL AFFECT THE REGION LATE IN THE PERIOD WITH
THE GFS MUCH FASTER THAN THE ECMWF. WENT WITH HPC GUIDANCE WHICH
LEANS TOWARD THE SLOWER ECMWF SOLUTION. INCLUDED CHC POPS
FRIDAY/FRIDAY NIGHT FOR SFC LOW AND TRAILING COLD FRONT FOLLOWED
BY CHC POPS ON SATURDAY AS UPPER LEVEL TROF DEEPENS OVER THE
NORTHEAST.
TEMPS THROUGH THE PERIOD WILL BE NEAR SEASONAL LEVELS, EXCEPT FOR
THURSDAY WHICH WILL BE SEVERAL DEGREES ABOVE NORMAL.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
00Z TAF UPDATE...
UPPER LEVEL LOW OVER THE ONTARIO PENINSULA...WILL GRADUALLY LIFT
NORTH-NORTHEAST INTO WESTERN QUEBEC DURING THIS TAF PERIOD. OUR
AREA HAS BEEN IN THE DRY SLOT UP TO THIS EVENING...BUT THE SHIELD
OF MOISTURE WRAPPING AROUND THE LOW...WILL SHIFT OVER THE
TERMINALS LATE TONIGHT INTO SUNDAY MORNING...YIELDING MVFR TO LOW
END VFR CLOUD DECK. ISOLATED TO SCATTERED INSTABILITY SHOWERS WILL
ALSO POP UP SUNDAY AFTERNOON FOR UPSTATE NY TERMINALS...WHICH
COULD RESULT IN BRIEF MVFR FLUCTUATIONS. CLOSER TO THE DEPARTING
UPPER LOW...AN ISOLATED LIGHTNING STRIKE IS NOT OUT OF THE
QUESTION FOR KSYR-KRME CORRIDOR SUNDAY AFTERNOON. LIGHT WINDS OVERNIGHT
BECOMING WSW ON SUNDAY WITH GUSTS TO 10-15 KTS.
OUTLOOK...
SUN NGT-MON NGT...MAINLY VFR.
TUE-WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-THU...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY THU MRNG.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...DJN
SHORT TERM...TAC
LONG TERM...RRM
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
712 PM EDT SAT AUG 11 2012
.SYNOPSIS...
A LARGE UPPER LEVEL STORM SYSTEM WILL SPIN OVER SOUTHEASTERN
CANADA THROUGH SUNDAY. DRIER AIR MOVING INTO NY AND PA WILL BRING
INCREASING SUNSHINE. HOWEVER THE PRESENCE OF THE STORM SYSTEM,
WILL KEEP A CHANCE FOR ISOLATED SHOWERS IN THE FORECAST THROUGH
SUNDAY...ESPECIALLY IN UPSTATE NEW YORK. HIGH PRESSURE WILL BE
OVER THE AREA MONDAY WITH DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDATE 700 PM...DRY SLOT CONTINUES OVER HEART OF THE WFO BINGAMTON
FORECAST AREA AS DRIER AND COOLER AIR SLOWLY BLEEDS EWRD FROM WRN NY
AND WRN PA. SPC ANALYSIS SHOWS THAT MOST OF THE CAPE HAS NOW
PUSHED E OF C NY INTO ERN NY AS LOW-LEVEL DRY ADVECTION CONTINUES
ON SW FLO. WITH CONTINUED LL DRY ADVECTION AND THE LOSS OF SFC
HEATING THIS EVE...CONVECTIVE ACVTY WILL ADVECT EAST AND DIMINISH.
SO HAVE ISLD POPS INITIALLY IN THE FAR EASTERN PART OF THE
BINGHAMTON FORECAST AREA...MAINLY CATSKILLS...JUST FOR A COUPLE MORE
HOURS...THEN LESS THAN 15 POPS. WEST OF THE BGM CWA THERE WAS A LOWER
STRATUS SHIELD THAT HAS FLOWED UP INTO THE ALLEGHENIES AND WILL
CONTINUE TO ADVECT NORTHEASTWARD TONIGHT TWD C NY AND NE PA.
TEMPERATURES WERE MUCH COOLER UNDER THIS STRATUS SHIELD. QUESTION
IS WHETHER IT WILL BE ABLE TO MAKE IT OVER THE ALLEGHENIES AS
THERE IS DOWNSLOPE FLOW ON SW WINDS. NAM AND RAP MODELS BOTH SHOW
THIS BY ENHANCING RH VALUES ON THE ALLEGENHIES AND DIMINISHING RH
ON THE OTHER SIDE. I BELIEVE WE WILL SEE SCT TO OCNL BKN CLDS INTO
C NY ESP...AND EVEN POTENTIALLY PART OF NE PA SO WILL KEEP GRIDS JUST
IN THE PC RANGE EXCEPT HIGHER TERRAIN OF STEUBEN COUNTY.
TWEEKED MINS...WINDS JUST A TOUCH. OTHERWISE NO SIG CHANGES.
UPDATE 330 PM...IN THE DRY SLOT THIS AFTERNOON OVER MUCH OF THE
CWA. SHOWERS ARE MOVING EAST OF THE AREA AHEAD OF A SLOW MOVING
COLD FRONT. MOST OF THIS WILL BE IN EASTERN NY BY 21Z. IN THE WEST
A SLOW MOVING STACKED LOW OVER SE ONTARIO WILL CONTINUE. THICKER
CLOUDS WILL SLOWLY MOVE INTO THE WESTERN COUNTIES THE REST OF
TODAY AND TONIGHT...AS THE LOW MOVES NORTHEAST INTO QUEBEC SUNDAY.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
UPDATE 330 PM...
SUNDAY WE WILL BE UNDER THE UPPER LEVEL TROF. SUNSHINE WILL CAUSE
LOW LEVEL INSTABILITY BUT MID LEVEL WARM AIR WILL INHIBIT DEEP
CONVECTION. SCATTERED TO ISOLATED SHOWERS IN NY AND THE NRN TIER
OF NE PA MAINLY IN THE AFTN. ALSO A THUNDERSTORM POSSIBLE IN THE
AFTN MOST LIKELY IN THE FINGER LAKES. SHOWERS WANE QUICKLY IN THE
EVENING AS THE TROF LIFTS OUT AND THE A SFC HIGH BUILDS IN.
THE HIGH WILL LAST THROUGH MONDAY INTO MONDAY NIGHT. MONDAY NIGHT
SHOULD BE DRY BEFORE THE NEXT UPPER LEVEL TROF AND SFC LOW MOVES
EAST FROM THE WESTERN GREAT LAKES. A DEEP SOUTHERLY FLOW WILL
BRING WARM AND MOIST AIR INTO THE REGION MONDAY NIGHT AND TUESDAY.
THE TIMING OF THIS SYSTEM IS GOOD BEING LATE IN THE DAY WITH A
STRONG COLD FRONT. A WARM FRONT WILL BRING SHOWERS IN THE
MORNING. CWA SHOULD BE IN THE WARM SECTOR IN THE AFTN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT WITH THE LARGE SCALE
FEATURES THROUGH THE EXTENDED PERIOD BUT SIGNIFICANT TIMING
DIFFERENCES EXISTS WITH SURFACE AND FRONTAL FEATURES. INITIALLY A
BROAD UPPER LEVEL TROF WILL BE OVER THE NORTHEAST WITH A SURFACE
LOW AND MID LEVEL SHORT WAVE MOVING THROUGH THE AREA TUESDAY NIGHT
INTO WEDNESDAY. WILL CONTINUE WITH CHC POPS THROUGH THE PERIOD
FOR SHOWERS ALONG WITH A SLIGHT CHC FOR TSRA. BRIEF UPPER LEVEL
RIDGING AND SFC HIGH PRES WILL PROVIDE DRY WEATHER WEDNESDAY NIGHT
THROUGH MUCH OF THURSDAY NIGHT. NEXT COLD FRONT AND DEEPENING
UPPER LEVEL TROF WILL AFFECT THE REGION LATE IN THE PERIOD WITH
THE GFS MUCH FASTER THAN THE ECMWF. WENT WITH HPC GUIDANCE WHICH
LEANS TOWARD THE SLOWER ECMWF SOLUTION. INCLUDED CHC POPS
FRIDAY/FRIDAY NIGHT FOR SFC LOW AND TRAILING COLD FRONT FOLLOWED
BY CHC POPS ON SATURDAY AS UPPER LEVEL TROF DEEPENS OVER THE
NORTHEAST.
TEMPS THROUGH THE PERIOD WILL BE NEAR SEASONAL LEVELS, EXCEPT FOR
THURSDAY WHICH WILL BE SEVERAL DEGREES ABOVE NORMAL.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
UPPER LEVEL LOW JUST NORTH OF CENTRAL LAKE ERIE WILL GRADUALLY LIFT
NORTHEAST THROUGH THIS TAF PERIOD. FOR NOW SCT/BKN CU AROUND 4K FT
WILL CONTINUE ACROSS THE TERMINALS THROUGH THIS EVENING. WIDELY
SCATTERED CONVECTION WILL PERSIST THROUGH LATE AFTERNOON NEAR KRME
TERMINAL BUT NOT INCLUDED IN TAF DUE TO LIMITED AREAL COVERAGE.
OVERNIGHT AS UPPER LEVEL LOW LIFTS NORTHEAST, WIDESPREAD MVFR CIGS
NOW ACROSS THE OHIO VALLEY WILL MOVE INTO REGION PRIMARILY AFTER
06Z. AT KAVP CIGS ARE EXPECTED TO REMAIN VFR. ON SUNDAY, BKN STRATO
CU WILL CONTINUE OVER THE REGION WITH CIGS AT KRME/KITH/KBGM
REMAINING MVFR WITH REST OF TERMINALS BECOMING VFR DURING THE MID
MORNING. SCATTERED SHOWERS ARE POSSIBLE AFTER 18Z.
THROUGH EARLY EVENING SOUTHWEST WINDS AROUND 10 KNOTS EXCEPT FOR
LIGHT SOUTHEAST AT KRME. OVERNIGHT, LIGHT WINDS BECOMING SOUTHWEST
ON SUNDAY AROUND 10 KNOTS.
OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY NIGHT...PRIMARILY VFR.
TUESDAY THROUGH WEDNESDAY...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WEDNESDAY NIGHT/THURSDAY...PRIMARILY VFR, EXCEPT FOR VALLEY FOG
EARLY THURSDAY MORNING.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC/DJN
NEAR TERM...DJN
SHORT TERM...TAC
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
206 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH OUR REGION FROM THE WEST TODAY AND
TONIGHT...THEN CROSS CENTRAL NORTH CAROLINA SATURDAY AND SATURDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM FRIDAY...
SKIES ARE OVERCAST WITH WIDESPREAD STRATUS THIS MORNING..BETWEEN AN
UPPER DISTURBANCE AND ASSOCIATED PRECIP DEPARTING TO THE
NORTHEAST...AND TWO MORE APPROACHING FROM BOTH THE NORTHWEST AND
SOUTHWEST LATER TODAY. A FEW LIGHT SHOWERS ARE MOVING THROUGH THE
PIEDMONT THIS MORNING...BUT OVERALL THERE IS A LULL ACROSS THE
CAROLINAS BETWEEN THE AFOREMENTIONED UPPER FEATURES. AN UPPER
LOW/SURFACE CYCLONE HAVE NOW DEVELOPED OVER THE GREAT LAKES AND THE
ASSOCIATED COLD FRONT EXTENDS SOUTH THROUGH OH/KY/TN....WITH A
STREAM OF 2 INCH PWS ACROSS THE NC/SC PIEDMONT AND COASTAL PLAIN. A
LINE OF PREFRONTAL CONVECTION IS CURRENTLY MOVING THROUGH EASTERN TN
AND WV...BUT THE DEEP LAYER FLOW IS FORECAST TO BECOME MORE
SOUTHWESTERLY AS THE UPPER TROUGH CONTINUES TO DEEPEN... AND THE
PROGRESSION OF CONVECTIVE LINE SHOULD SLOW AS IT CROSSES THE
MOUNTAINS THIS MORNING. IN FACT... HRRR FORECASTS SHOW A LINE OF
CONVECTION MOVING INTO THE WESTERN PIEDMONT CLOSER TO 00Z.
MEANWHILE...THE AFOREMENTIONED DISTURBANCE NEAR THE GULF COAST
SHOULD BE DRAWN NORTH-NORTHEASTWARD...APPROACHING THE SOUTHERN CWA
BY 00Z. WHILE A FEW SHOWERS AND STORMS WILL BE POSSIBLE THROUGH MID
AFTERNOON WITH WEAK DISTURBANCES IN THE MOIST SOUTHWESTERLY FLOW
ALOFT...WE SHOULD BE ABLE TO PUSH MORE SIGNIFICANT POPS BACK UNTIL
AFTER 21-22Z.
CONCERNING THE SEVERE THREAT THROUGH THIS EVENING...IT APPEARS THE
WIDESPREAD STRATUS MAY LINGER THROUGH MIDDAY...WITH MORNING PIREPS
CONTINUING TO REPORT 3K FT DEPTH TO THE STRATUS. VISIBLE IMAGERY
SHOWS MORE PROMINENT BREAKS IN THE CLOUDS OVER WESTERN NC AND OVER
THE COASTAL PLAIN. THUS...TWO INSTABILITY AXES MAY DEVELOP IN THESE
REGIONS...AND MODELS SUGGEST 1500 J/KG OR MORE OF MLCAPE
POSSIBLE..WITH VALUES AROUND 1000 J/KG OVER THE PIEDMONT. STRONGER
DEEP LAYER SHEAR WILL BE LOCATED WEST OF THE MOUNTAINS FOR MOST OF
THE DAY...ALTHOUGH THE MID LEVEL HEIGHT GRADIENT WILL BEGIN TO
STRENGTHEN THIS EVENING...AND THE RAP SHOWS 25-35KT OF 0-6KM BULK
SHEAR DEVELOPING OVER THE WESTERN PIEDMONT. TO THE EAST...WHERE DEEP
LAYER FLOW IS A BIT WEAKER...MORE LIKE 20-25KT OF DEEP BULK
SHEAR...MORNING RAOBS SUGGEST A BELT OF 30KT 925-850MB FLOW EXISTS
AND THE SPC MESOANALYSIS CURRENTLY SHOWS AN AXIS OF 20KT 0-1KM SHEAR
OVER THE COASTAL PLAIN. SO WHILE DEEP SHEAR MAY NOT SUPPORT
SUPERCELLULAR ACTIVITY... IT IS POSSIBLE THAT A FEW CLUSTERS OF
STORMS OR EVEN DISCRETE CELLS WITH WEAK ROTATION COULD DEVELOP THIS
EVENING. THIS IS ALL SIGNIFICANTLY DEPENDENT ON OUR DIURNAL
DESTABILIZATION AND WHETHER OR NOT CONVECTION CAN HOLD TOGETHER
SINCE THE MAIN FORCING MECHANISMS WILL NOT ARRIVE UNTIL CLOSER TO
00Z.
OTHERWISE...HAVE MADE SOME MINOR ADJUSTMENTS TO AFTERNOON
HIGHS...WITH SLIGHTLY HIGHER VALUES OVER THE EASTERN AND WESTERN
AREAS...BUT GENERALLY 84-87 SHOULD STILL BE ATTAINABLE IF BREAKS IN
CLOUDS DEVELOP BY MID AFTERNOON. -SMITH
TONIGHT...SW FLOW WILL DEEPEN OVER CENTRAL NC IN RESPONSE TO
AMPLIFYING TROUGH OVER THE EASTERN LAKES-OH VALLEY. THIS SUGGEST A
THREAT FOR SHOWERS-STORMS TO TRAIN REPEATEDLY ACROSS THE SAME
LOCATIONS. SINCE FLOW WILL BE TAPPING AN AIR MASS WITH A VERY HIGH
MOISTURE CONTENT OVER THE NORTHERN GULF...COULD SEE A MODERATE
FLASH FLOOD THREAT DEVELOP OVER CENTRAL NC OVERNIGHT. MODEL GUIDANCE
DEPICT BEST LIFT ALOFT IN ASSOCIATION WITH THE UPPER JET WHILE LIFT
BELOW 700MB WEAK AT BEST. THUS PLAN TO HAVE POPS NO HIGHER THAN
70-80 PERCENT OVER THE WEST HALF OVERNIGHT...TRENDING TO NEAR 60
PERCENT SE (WHICH MAY BE GENEROUS).
TEMPS TODAY DEPENDENT ON THE AMOUNT OF SUN THAT OCCURS. EXPECT
CONDITIONS TODAY SIMILAR TO THE PAST FEW DAYS WHERE MAX TEMPS IN THE
MID 80S COMMON. MIN TEMPS TONIGHT UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 315 AM FRIDAY...
SATURDAY...EXPECT SCATTERED CONVECTION TO BE ONGOING ACROSS CENTRAL
NC SATURDAY MORNING. AS AIR MASS BECOMES MARGINALLY UNSTABLE IN THE
AFTERNOON AND SURFACE COLD FRONT ENTERS THE MOUNTAINS...SHOULD SEE
AN UPTICK IN CONVECTIVE COVERAGE IN THE AFTERNOON. BULK SHEAR VALUES
30-35KTS ACROSS THE ENTIRE FORECAST AREA SUGGEST DECENT POTENTIAL
FOR ORGANIZED STORMS IN THE FORM OF BROKEN LINE SEGMENTS THOUGH
INSTABILITY MAY BE LACKING FOR SEVERE STORMS DUE TO LIMITED
INSOLATION CAUSED BY CONSIDERABLE CLOUDINESS AND SCATTERED SHOWERS.
IF PARTIAL SUN OCCURS IN THE LATE MORNING INTO THE
AFTERNOON...PROBABILITY FOR SEVERE STORMS WILL INCREASE
EXPONENTIALLY. AGAIN...DUE TO TAP OF TROPICAL MOISTURE AND DEEP SW
FLOW...COULD SEE SHOWERS-STORMS TRAIN NEWD ACROSS THE
REGION...LEADING TO POSSIBLE FLASH FLOODING EPISODE.
MAX TEMPS MAINLY IN THE MID 80S THOUGH IF SHOWERS MORE
WIDESPREAD...COULD SEE MAX TEMPS 3-5 DEGREES COOLER...ESPECIALLY
WEST HALF.
WITH PASSAGE OF LOW-MID TROUGH SATURDAY EVENING IN THE WEST...EXPECT
CHANCES FOR CONVECTION TO BEGIN TO DECREASE IN THIS REGION.
MEANWHILE DECENT CHANCES FOR SCATTERED SHOWERS-STORMS SHOULD PERSIST
THROUGH MIDNIGHT IN THE EAST. MIN TEMPS MID 60S NW TO NEAR 70-LOWER
70S SE.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 245 AM FRIDAY...
MID/UPPER LOW EXPECTED TO BE CENTERED INVOF THE NORTHERN GREAT LAKES
REGION AND NEAR THE ONTARIO/QUEBEC BORDER 12Z SUNDAY IS EXPECTED TO
CONTINUING LIFTING NNE ON SUNDAY. THIS WILL RESULT IN FLOW ALOFT
ACROSS CENTRAL NC BECOMING MORE WESTERLY WITH DRIER AIR ALOFT
CONTINUING TO FILTER INTO THE AREA. AT THE SURFACE THE WEAK FRONT IS
EXPECTED TO WASHOUT/DISSIPATE ACROSS THE AREA ON SUNDAY INTO MONDAY.
GIVEN THIS ALONG WITH THE DEPARTURE OF THE FORCING ALOFT AND MOIST
AIR ALOFT... EXPECTED GENERALLY DRY CONDITIONS ON SUNDAY INTO MONDAY
(OUTSIDE OF POSSIBLE A FEW LINGERING SHOWERS/STORMS ACROSS THE FAR
EAST ON SUNDAY... SLIGHT CHANCE AT BEST THOUGH). CHANCE FOR POPS ARE
EXPECTED TO INCREASE BY TUESDAY INTO TUESDAY NIGHT/PERHAPS LINGERING
INTO WEDNESDAY/THURSDAY AS A LOW AMPLITUDE S/W TROUGH AND ASSOCIATED
WEAK COLD FRONT/SURFACE TROUGH MOVE ACROSS THE AREA. GIVEN TIMING
AND SOME STRENGTH DIFFERENCES WILL CONTINUE TO ONLY GO WITH A LOW
END CHANCE POPS FOR TUESDAY/TUESDAY EVENING... WITH DIURNAL SLIGHT
CHANCE POPS FOR WEDNESDAY INTO THURSDAY WITH THE REMNANT LINGERING
SURFACE TROUGH. HIGH TEMPS DURING THE PERIOD ARE EXPECTED TO
GENERALLY BE IN THE UPPER 80S TO LOWER 90S... WITH LOWS GENERALLY
RANGING FROM THE UPPER 60S TO LOWER 70S (WITH MAYBE SOME LOW TEMPS
IN THE LOWER TO MID 60S IN THE RURAL LOCATIONS AND NORTHWEST
PIEDMONT ON MONDAY MORNING).
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 200 PM FRIDAY...
LINGERING MVFR CEILINGS ACROSS CENTRAL NC WILL CONTINUE TO THIN OUT
AND IMPROVE TO VFR BY 19 TO 20Z. AIRMASS WILL THEN
DESTABILIZE...SUPPORTING SCATTERED SHOWERS AND STORMS BETWEEN 20 TO
24Z...PARTICULARLY IN THE VICINITY OF KFAY AND KRWI WHERE LEAD
SHORTWAVE DISTURBANCE RESIDES. CONVECTIVE MIXING WILL ALSO RESULT IN
OCCASIONAL BREEZY SWLY WINDS BETWEEN 15 TO 18KTS.
A SFC FRONT WILL PUSH EAST OF THE MTNS BETWEEN 03Z-06Z TONIGHT.
WESTERN PORTIONS OF THE FORECAST AREA...INCLUDING THE TRIAD
TERMINALS...ARE EXPECTED TO SEE BETTER CONVECTIVE RAIN CHANCES
WITH THE APPROACH OF THE FRONT. THE FRONT WILL THEN MOVE SLOWLY
THROUGH THE AREA SATURDAY AND SATURDAY EVENING. EXPECT BANDS OF
SHOWERS AND T-STORMS ACROSS CENTRAL NC THROUGH 18Z SATURDAY WITH
ASSOCIATED MVFR CONDITIONS.
DRIER MORE STABLE AIR WILL GRADUALLY OVERSPREAD CENTRAL NC LATE
SATURDAY NIGHT INTO SUNDAY LEADING TO IMPROVING AVIATION CONDITIONS.
MAINLY VFR CONDITIONS EXPECTED MONDAY INTO TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1030 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH OUR REGION FROM THE WEST TODAY AND
TONIGHT...THEN CROSS CENTRAL NORTH CAROLINA SATURDAY AND SATURDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM FRIDAY...
SKIES ARE OVERCAST WITH WIDESPREAD STRATUS THIS MORNING..BETWEEN AN
UPPER DISTURBANCE AND ASSOCIATED PRECIP DEPARTING TO THE
NORTHEAST...AND TWO MORE APPROACHING FROM BOTH THE NORTHWEST AND
SOUTHWEST LATER TODAY. A FEW LIGHT SHOWERS ARE MOVING THROUGH THE
PIEDMONT THIS MORNING...BUT OVERALL THERE IS A LULL ACROSS THE
CAROLINAS BETWEEN THE AFOREMENTIONED UPPER FEATURES. AN UPPER
LOW/SURFACE CYCLONE HAVE NOW DEVELOPED OVER THE GREAT LAKES AND THE
ASSOCIATED COLD FRONT EXTENDS SOUTH THROUGH OH/KY/TN....WITH A
STREAM OF 2 INCH PWS ACROSS THE NC/SC PIEDMONT AND COASTAL PLAIN. A
LINE OF PREFRONTAL CONVECTION IS CURRENTLY MOVING THROUGH EASTERN TN
AND WV...BUT THE DEEP LAYER FLOW IS FORECAST TO BECOME MORE
SOUTHWESTERLY AS THE UPPER TROUGH CONTINUES TO DEEPEN... AND THE
PROGRESSION OF CONVECTIVE LINE SHOULD SLOW AS IT CROSSES THE
MOUNTAINS THIS MORNING. IN FACT... HRRR FORECASTS SHOW A LINE OF
CONVECTION MOVING INTO THE WESTERN PIEDMONT CLOSER TO 00Z.
MEANWHILE...THE AFOREMENTIONED DISTURBANCE NEAR THE GULF COAST
SHOULD BE DRAWN NORTH-NORTHEASTWARD...APPROACHING THE SOUTHERN CWA
BY 00Z. WHILE A FEW SHOWERS AND STORMS WILL BE POSSIBLE THROUGH MID
AFTERNOON WITH WEAK DISTURBANCES IN THE MOIST SOUTHWESTERLY FLOW
ALOFT...WE SHOULD BE ABLE TO PUSH MORE SIGNIFICANT POPS BACK UNTIL
AFTER 21-22Z.
CONCERNING THE SEVERE THREAT THROUGH THIS EVENING...IT APPEARS THE
WIDESPREAD STRATUS MAY LINGER THROUGH MIDDAY...WITH MORNING PIREPS
CONTINUING TO REPORT 3K FT DEPTH TO THE STRATUS. VISIBLE IMAGERY
SHOWS MORE PROMINENT BREAKS IN THE CLOUDS OVER WESTERN NC AND OVER
THE COASTAL PLAIN. THUS...TWO INSTABILITY AXES MAY DEVELOP IN THESE
REGIONS...AND MODELS SUGGEST 1500 J/KG OR MORE OF MLCAPE
POSSIBLE..WITH VALUES AROUND 1000 J/KG OVER THE PIEDMONT. STRONGER
DEEP LAYER SHEAR WILL BE LOCATED WEST OF THE MOUNTAINS FOR MOST OF
THE DAY...ALTHOUGH THE MID LEVEL HEIGHT GRADIENT WILL BEGIN TO
STRENGTHEN THIS EVENING...AND THE RAP SHOWS 25-35KT OF 0-6KM BULK
SHEAR DEVELOPING OVER THE WESTERN PIEDMONT. TO THE EAST...WHERE DEEP
LAYER FLOW IS A BIT WEAKER...MORE LIKE 20-25KT OF DEEP BULK
SHEAR...MORNING RAOBS SUGGEST A BELT OF 30KT 925-850MB FLOW EXISTS
AND THE SPC MESOANALYSIS CURRENTLY SHOWS AN AXIS OF 20KT 0-1KM SHEAR
OVER THE COASTAL PLAIN. SO WHILE DEEP SHEAR MAY NOT SUPPORT
SUPERCELLULAR ACTIVITY... IT IS POSSIBLE THAT A FEW CLUSTERS OF
STORMS OR EVEN DISCRETE CELLS WITH WEAK ROTATION COULD DEVELOP THIS
EVENING. THIS IS ALL SIGNIFICANTLY DEPENDENT ON OUR DIURNAL
DESTABILIZATION AND WHETHER OR NOT CONVECTION CAN HOLD TOGETHER
SINCE THE MAIN FORCING MECHANISMS WILL NOT ARRIVE UNTIL CLOSER TO
00Z.
OTHERWISE...HAVE MADE SOME MINOR ADJUSTMENTS TO AFTERNOON
HIGHS...WITH SLIGHTLY HIGHER VALUES OVER THE EASTERN AND WESTERN
AREAS...BUT GENERALLY 84-87 SHOULD STILL BE ATTAINABLE IF BREAKS IN
CLOUDS DEVELOP BY MID AFTERNOON. -SMITH
TONIGHT...SW FLOW WILL DEEPEN OVER CENTRAL NC IN RESPONSE TO
AMPLIFYING TROUGH OVER THE EASTERN LAKES-OH VALLEY. THIS SUGGEST A
THREAT FOR SHOWERS-STORMS TO TRAIN REPEATEDLY ACROSS THE SAME
LOCATIONS. SINCE FLOW WILL BE TAPPING AN AIR MASS WITH A VERY HIGH
MOISTURE CONTENT OVER THE NORTHERN GULF...COULD SEE A MODERATE
FLASH FLOOD THREAT DEVELOP OVER CENTRAL NC OVERNIGHT. MODEL GUIDANCE
DEPICT BEST LIFT ALOFT IN ASSOCIATION WITH THE UPPER JET WHILE LIFT
BELOW 700MB WEAK AT BEST. THUS PLAN TO HAVE POPS NO HIGHER THAN
70-80 PERCENT OVER THE WEST HALF OVERNIGHT...TRENDING TO NEAR 60
PERCENT SE (WHICH MAY BE GENEROUS).
TEMPS TODAY DEPENDENT ON THE AMOUNT OF SUN THAT OCCURS. EXPECT
CONDITIONS TODAY SIMILAR TO THE PAST FEW DAYS WHERE MAX TEMPS IN THE
MID 80S COMMON. MIN TEMPS TONIGHT UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 315 AM FRIDAY...
SATURDAY...EXPECT SCATTERED CONVECTION TO BE ONGOING ACROSS CENTRAL
NC SATURDAY MORNING. AS AIR MASS BECOMES MARGINALLY UNSTABLE IN THE
AFTERNOON AND SURFACE COLD FRONT ENTERS THE MOUNTAINS...SHOULD SEE
AN UPTICK IN CONVECTIVE COVERAGE IN THE AFTERNOON. BULK SHEAR VALUES
30-35KTS ACROSS THE ENTIRE FORECAST AREA SUGGEST DECENT POTENTIAL
FOR ORGANIZED STORMS IN THE FORM OF BROKEN LINE SEGMENTS THOUGH
INSTABILITY MAY BE LACKING FOR SEVERE STORMS DUE TO LIMITED
INSOLATION CAUSED BY CONSIDERABLE CLOUDINESS AND SCATTERED SHOWERS.
IF PARTIAL SUN OCCURS IN THE LATE MORNING INTO THE
AFTERNOON...PROBABILITY FOR SEVERE STORMS WILL INCREASE
EXPONENTIALLY. AGAIN...DUE TO TAP OF TROPICAL MOISTURE AND DEEP SW
FLOW...COULD SEE SHOWERS-STORMS TRAIN NEWD ACROSS THE
REGION...LEADING TO POSSIBLE FLASH FLOODING EPISODE.
MAX TEMPS MAINLY IN THE MID 80S THOUGH IF SHOWERS MORE
WIDESPREAD...COULD SEE MAX TEMPS 3-5 DEGREES COOLER...ESPECIALLY
WEST HALF.
WITH PASSAGE OF LOW-MID TROUGH SATURDAY EVENING IN THE WEST...EXPECT
CHANCES FOR CONVECTION TO BEGIN TO DECREASE IN THIS REGION.
MEANWHILE DECENT CHANCES FOR SCATTERED SHOWERS-STORMS SHOULD PERSIST
THROUGH MIDNIGHT IN THE EAST. MIN TEMPS MID 60S NW TO NEAR 70-LOWER
70S SE.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 245 AM FRIDAY...
MID/UPPER LOW EXPECTED TO BE CENTERED INVOF THE NORTHERN GREAT LAKES
REGION AND NEAR THE ONTARIO/QUEBEC BORDER 12Z SUNDAY IS EXPECTED TO
CONTINUING LIFTING NNE ON SUNDAY. THIS WILL RESULT IN FLOW ALOFT
ACROSS CENTRAL NC BECOMING MORE WESTERLY WITH DRIER AIR ALOFT
CONTINUING TO FILTER INTO THE AREA. AT THE SURFACE THE WEAK FRONT IS
EXPECTED TO WASHOUT/DISSIPATE ACROSS THE AREA ON SUNDAY INTO MONDAY.
GIVEN THIS ALONG WITH THE DEPARTURE OF THE FORCING ALOFT AND MOIST
AIR ALOFT... EXPECTED GENERALLY DRY CONDITIONS ON SUNDAY INTO MONDAY
(OUTSIDE OF POSSIBLE A FEW LINGERING SHOWERS/STORMS ACROSS THE FAR
EAST ON SUNDAY... SLIGHT CHANCE AT BEST THOUGH). CHANCE FOR POPS ARE
EXPECTED TO INCREASE BY TUESDAY INTO TUESDAY NIGHT/PERHAPS LINGERING
INTO WEDNESDAY/THURSDAY AS A LOW AMPLITUDE S/W TROUGH AND ASSOCIATED
WEAK COLD FRONT/SURFACE TROUGH MOVE ACROSS THE AREA. GIVEN TIMING
AND SOME STRENGTH DIFFERENCES WILL CONTINUE TO ONLY GO WITH A LOW
END CHANCE POPS FOR TUESDAY/TUESDAY EVENING... WITH DIURNAL SLIGHT
CHANCE POPS FOR WEDNESDAY INTO THURSDAY WITH THE REMNANT LINGERING
SURFACE TROUGH. HIGH TEMPS DURING THE PERIOD ARE EXPECTED TO
GENERALLY BE IN THE UPPER 80S TO LOWER 90S... WITH LOWS GENERALLY
RANGING FROM THE UPPER 60S TO LOWER 70S (WITH MAYBE SOME LOW TEMPS
IN THE LOWER TO MID 60S IN THE RURAL LOCATIONS AND NORTHWEST
PIEDMONT ON MONDAY MORNING).
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 707 AM FRIDAY...
LOW CLOUDS HAVE DEVELOP OVER MOST OF CENTRAL NC EARLY THIS MORNING
IN WAKE OF THE SHOWERS AND SCATTERED T-STORMS THAT CROSSED THE
WESTERN COUNTIES OVERNIGHT. CEILINGS IN THE IFR/LOW END MVFR RANGE.
CEILINGS SHOULD GRADUALLY LIFT TOT HE HIGH END MVFR/LOW END VFR BY
LATE MORNING. ANY FOG ACROSS THE REGION SHOULD BE SPOTTY AND
DIMINISH BY MID MORNING (IF NOT SOONER).
WHILE ISOLATED SHOWERS POSSIBLE THROUGH EARLY AFTERNOON...EXPECT
CONVECTION TO GROW IN COVERAGE AND INTENSITY BY MID
AFTERNOON...PARTICULARLY IN THE VICINITY OF KFAY AND KRWI WHERE
INITIAL MID LEVEL TROUGH WILL RESIDE. IN THE NW PIEDMONT INCLUDING
THE TRIAD TERMINALS...BETTER CONVECTIVE PROBABILITIES MAY HOLD OFF
UNTIL EVENING AS A MID LEVEL TROUGH APPROACHES FROM THE NW. THIS
FEATURE MAY SUSTAIN SCATTERED CONVECTION IN VICINITY OF KINT AND
KGSO WELL INTO THE NIGHT.
EXPECT EPISODES OF SCATTERED SHOWERS AND T-STORMS ACROSS CENTRAL NC
SATURDAY INTO SATURDAY EVENING WITH ASSOCIATED MVFR CONDITIONS. AT
THIS TIME...IT APPEARS THE HEAVIER SHOWERS AND STORMS WILL OCCUR
SATURDAY AFTERNOON ALONG AND EAST OF HIGHWAY 1.
DRIER MORE STABLE AIR WILL GRADUALLY OVERSPREAD CENTRAL NC LATE
SATURDAY NIGHT INTO SUNDAY LEADING TO IMPROVING AVIATION CONDITIONS.
MAINLY VFR CONDITIONS EXPECTED MONDAY INTO TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
153 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE OVER THE PIEDMONT THIS AFTERNOON THROUGH
FRIDAY WILL GIVE WAY TO A COLD FRONT ON SATURDAY. HIGH PRESSURE
WILL BUILD INTO THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM THURSDAY...CONTINUED MAIN DILEMMA FOR THE OVERNIGHT
PERIOD WILL BE THE TIMING AND COVERAGE OF THE CONVECTIVE ACTIVITY
APPROACHING FROM THE SOUTHWEST. VARIOUS MODEL BUFR SOUNDINGS
INDICATE AN INCREASE IN MOISTURE THIS EVENING AND OVERNIGHT VIA PWS
REBOUNDING BACK OVER 2+ INCHES. WEAK MID LEVEL SHEARED VORT AND AN
UPPER LEVEL JET MAX TO TRACK NE ACROSS THE CAROLINAS TONIGHT...WITH
THE RIGHT REAR QUADRANT OF THIS UPPER JET AND SOURCE OF UPPER LEVEL
DIVERGENCE TO PUSH ACROSS OR AFFECT THE FA MAINLY AFTER MIDNIGHT
TONIGHT. THE RR QUAD WILL BE A FAVORED AREA OF UVVS AND AS A RESULT
WILL INCREASE POPS TO GOOD CHANCE OR POSSIBLY LIKELY LEADING TO BUT
MAINLY OCCURRING AFTER MIDNIGHT TONIGHT. THE DAYS HEATING COMBINED
WITH DYNAMICS ALOFT HAS HELPED CONVECTION REACH SVR CRITERIA WELL
UPSTREAM FROM THE FA. THE DAYS INSOLATION WILL BE DONE-WITH BY THE
TIME THE BULK OF THE PCPN PUSHES TO/ACROSS THE ILM CWA LATER
TONIGHT...AND AS A RESULT DO NOT ANTICIPATE PULSING SVR ACTIVITY.
HOWEVER...DO LIKE THE HEAVY RAIN/GUSTY WINDS TO SUFFIX AFTER THE
MENTIONING OF THE CONVECTION OVERNIGHT. EXPECT 20-30 MPH STORM
MOTIONS...WHICH SHOULD HELP LOWER THE FLOOD POTENTIAL. HOWEVER...IF
ACTIVITY BEGINS TO TRAIN...THEN WILL HAVE TO REVISIT THE FLOOD
ISSUE. AS FOR MIN TEMPS...WILL STAY ON THE HIGHER SIDE OF MOS
GUIDANCE DUE TO SKIES HAVING CLOUDED UP ALONG WITH THE POTENTIAL
MORNING OCCURRENCE OF PCPN.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...AN AMPLIFYING H5 TROUGH...APPROACHING COLD
FRONT AND PRECIPITABLE WATER SURGING ABOVE 2 INCHES WILL RESULT IN
AN UNSETTLED SHORT TERM PERIOD. THE FRONT IS EXPECTED TO STALL IN
THE VICINITY AS IT BECOMES ORIENTED WITH THE FLOW ALOFT. THUS THE
FORECAST INDICATES CHANCE TO LIKELY POPS THROUGH SATURDAY NIGHT.
FAVORED THE COOLER MET NUMBERS EACH DAY GIVEN THE EXPECTED CLOUD
COVER. THE CLOUD COVER COULD ALSO LIMIT DEEPER CONVECTION FROM
DEVELOPING...HOWEVER HEATING WILL LIKELY LEAD TO AT LEAST MODERATE
INSTABILITY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...COLD FRONT WILL BE MOVING OFFSHORE WHILE
DISSIPATING AT THE START OF THE PERIOD. THIS WILL BRING AN END TO
PRECIP THROUGH SUNDAY AFTN AS DRIER AND COOLER AIR WORKS IN BEHIND
THIS BOUNDARY. FORECAST SOUNDINGS SUGGEST CLEARING WILL OCCUR
RAPIDLY DURING SUNDAY...BUT EVEN WITH AMPLE SUNSHINE...TEMPS WILL
STRUGGLE TO CLIMO AS SOME COOL ADVECTION OCCURS THROUGH MAX HEATING.
EXPECT TEMPS AT OR JUST BELOW 90 SUNDAY WITH MINS FALLING TO NEAR 70.
UPPER TROUGH WEAKENS AND SPINS OFF TO THE NORTHEAST AS SUBTLE
RIDGING DEVELOPS ACROSS THE SOUTHEAST. RISING 1000-500MB THICKNESSES
AND WARMING MID-LEVEL TEMPS WILL COMBINE WITH DRY W/NW FLOW TO
PREVENT WIDESPREAD CONVECTION MON EVEN WITH SLIGHTLY STEEPENED ML
LAPSE RATES. MOISTURE RETURN IS SLOW TO DEVELOP TUESDAY...BUT SOME
GUIDANCE INDICATING THAT A COASTAL TROUGH MAY HELP SPREAD SOME
MOISTURE TOWARDS THE COAST AND WILL BUMP POP TO CHC TUESDAY...ACROSS
THE EAST. TEMPS WILL REMAIN AROUND CLIMO...A FEW DEGREES EITHER SIDE
OF 90 AND 70.
FOR THE MID/LATE WEEK...BROAD TROUGHING REMAINS ACROSS THE EAST
WHILE WEAK IMPULSES MAY SPAWN AFTERNOON STORMS EACH DAY.
HOWEVER...WITH MID LEVEL DRY AIR PERSISTING...CONVECTION WILL BE
CAPPED AT SCHC/SILENT THIS FAR OUT IN TIME. A REINFORCING SHOT OF
COOL/DRY AIR MAY PUSH THROUGH THURSDAY AS UPPER VORT MOVES ACROSS
NEW ENGLAND WHICH WILL HELP KEEP TEMPS RIGHT AROUND CLIMO THROUGH
THE END OF THE PERIOD.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...EXPECT VCTS AT ILM UNTIL AROUND 07Z. PRECIP ENDS BUT
REDEVELOPS COAST TERMS AFT 08Z-09Z. AT FLO/LBT TEMPO MVFR CIGS/VSBYS
IN BR 08-12Z. CONFIDENCE IN TIMING OF BR OR RW NOT REAL HIGH. TEMPO
MVFR LIKELY WITH PRECIP...BUT WILL NOT INCLUDE IFR DUE TO SCT NATURE
OF ACTIVITY ALTHOUGH SHORT TERM IFR PSBL IF CELL MOVES OVR A COAST
TERM. AS A SHORT WAVE APPROACHES PRECIP RE-DEVLPS BTWN COAST TERMS
AND INLAND TERMS BY 18Z...BUT CONFIDENCE LOW DUE TO SUBSIDENCE
BEHIND THIS MORNINGS ACTIVITY. IF DEVELOPMENT OCCURS IFR/TS WILL
OCCUR MAINLY COAST TERMS 18-00Z. LOW CONFIDENCE TS AT FLO/LBT 18-00Z.
EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. VFR MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM THURSDAY...PROGGED SFC PRESSURE PATTERN AND TIGHTENING
GRADIENT...WILL YIELD WINDS FROM SSW-SW THIS EVENING AND
OVERNIGHT...ALONG WITH SPEEDS INCREASING FROM AROUND 15 KT...EXCEPT
15-20 KT FOR THE ILM NC WATERS. SIGNIFICANT SEAS ...MAINLY FROM WIND
DRIVEN 3-5 SECOND PERIOD WAVES...WILL BUILD TO 3 TO 5 FT NORTH OF
LITTLE RIVER INLET...AND 2 TO 4 FT SOUTH OF THE INLET. SEAS ARE
EXPECTED TO BUILD TO 4 TO 6 FT FOR THE ILM NC WATERS FRIDAY...WITH
SW WINDS 15-20 KT. STILL NOT ALL THAT CONFIDENT AT THE MOMENT WITH
REGARD TO RAISING A SCA/SCEC. IF DATA FROM TONIGHTS 00Z EARLY MODEL
RUNS INDICATE THIS INCREASED SCA POTENTIAL...MAY GO AHEAD AND ISSUE
A SCA OR SCEC AT THE LATE NIGHT UPDATE.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...SOUTH-SOUTHWEST FETCH WILL BE IN PLACE THROUGH
THE BULK OF THE SHORT TERM PERIOD. IT APPEARS THE PRESSURE GRADIENT
WILL BE AT ITS GREATEST LATE FRIDAY AFTERNOON INTO THE EVENING. THE
FLOW WILL FINALLY BEGIN TO WEAKEN SATURDAY NIGHT WITH THE FRONT IN
THE VICINITY. SEAS MAY REACH MARGINAL SMALL CRAFT THRESHOLDS BY
FRIDAY EVENING...WITH EXERCISE CAUTION CONDITIONS EXPECTED DURING
THE MAJORITY OF THE PERIOD.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...PREDOMINANT SW FLOW TO PERSIST THROUGH THE
EXTENDED AS BERMUDA HIGH RIDGES IN FROM THE EAST. A FAIRLY WEAK
PRESSURE GRADIENT WILL EXIST HOWEVER...SO WINDS WILL BE AROUND 10
KTS OR LESS THROUGH MUCH OF THE PERIOD. THE LIGHT WINDS WILL PRODUCE
A 2-3FT/5SEC SW WIND CHOP WHICH WILL COMBINE WITH A 2FT/9SEC SE
SWELL TO PRODUCE OVERALL WAVE HEIGHTS OF 2-3 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 9 AM EDT
SATURDAY FOR AMZ250-252.
&&
$$
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
809 PM CDT SAT AUG 11 2012
.DISCUSSION...
FORECAST CHALLENGE TONIGHT IS PRECIPITATION AND CORRECTLY
ANALYZING RADAR DATA IN A DATA SPARSE REGION. RADAR ECHOES HAVE
BEEN SHOWING WHAT APPEARS TO BE RAIN OVER WESTERN ZONES...WITH
VERY FEW REPORTS OF ACTUAL RAINFALL AT THE SFC...TYPICAL WITH THE
DRIER AIR MASS THAT HAS BEEN IN PLACE. FOR BLENDING PURPOSES HAVE
BUMPED UP POPS BUT WITHIN THE CHANCE RANGE. THERE DOES APPEAR TO
BE A SHOWER OVER SOUTHERN TOWNER COUNTY...BUT FOR THE MOST PART
BELIEVE ECHOES ARE CLOUDS AND VIRGA. WILL KEEP THE LOWER POPS IN
AFT 06Z. FOR SOUTH ZONES...DID STRETCH LIKELY POPS MORE INTO
SOUTHERN VALLEY DUE TO CURRENT TRENDS AND HIGHER REFLECTIVITIES IN
THE AREA...ALTHOUGH THE BAND IS CURRENTLY UNDERCUTTING THE CWA.
HIGHER POPS ARE BETTING SHOWERS OVER SARGENT COUNTY WILL
EVENTUALLY ADVECT EAST IN TO RICHLAND AND WILKIN COUNTIES. TEMPS
WERE UPDATED WITH HRRR DATA AND SEEM REALISTIC CONSIDERING THE
ENTIRE CWA IS NOW CLOUDY FOR THE MOST PART. THINK OVERNIGHT LOWS
WILL GENERALLY BE IN THE UPPER 50S ALTHOUGH COOLER WHERE RAIN IS
FALLING.
&&
.AVIATION...
EXPECT VFR CONDS TONIGHT WITH ONLY THREAT FOR RAIN BEING AT FAR
AND DVL. CONFIDENCE FOR ANY RAIN AT FAR IS DIMINISHING AS DRIER
AIR IS CONTROLLING THE SHOW RIGHT NOW. DVL AREA WILL LIKELY ONLY
RECEIVE SPRINKLES OR VERY LIGHT RAIN. CIGS WILL BE LOWEST AT DVL
AND AROUND 4K FT.
&&
.PREV DISCUSSION... /ISSUED 240 PM CDT SAT AUG 11 2012/
SHORT TERM...
MAIN CHALLENGE FOR THE SHORT TERM FORECAST WILL BE PCPN CHANCES
AND COVERAGE TONIGHT INTO SUNDAY. INHERITED FORECAST LOOKING GOOD
ON BOTH THESE PARAMETERS SO WILL STICK PRETTY CLOSE TO IT.
TONIGHT...QUITE A BIT OF CLOUD COVER ACROSS THE REGION WHICH WILL
HANG AROUND TONIGHT AND KEEP TEMPS FROM FALLING INTO THE UPPER
30S LIKE IT HAS DONE THE PAST COUPLE OF NIGHTS. THINNEST CLOUD
COVER WILL BE IN THE EAST/NORTHEAST. AS FAR AS PCPN GOES IT HAS
BEEN SLOWLY APPROACHING THE SOUTHWEST FA BUT NOT MAKING AS MUCH
HEADWAY INTO THE NORTHWEST. THIS HAS BEEN EXPECTED AS MOST OF THE
PCPN IS FORECAST TO TRACK DOWN INTO NORTHEAST SD AND PORTIONS OF
WESTERN MN. OTHER OFFICES TO THE SOUTH BOOSTED UP PCPN CHANCES SO
WILL BLEND AND GO LIKELY CHANCES ACROSS THE FAR SOUTH LATER
TONIGHT. PCPN AMOUNTS HAVE NOT BEEN THAT HIGH SO DO NOT HAVE
EXPECTATIONS OF MUCH RAINFALL EVEN IN THE LIKELY AREA TONIGHT.
SUN-TUE...WILL CONTINUE THE LIKELY CHANCES FOR PCPN INTO SUNDAY
MORNING ACROSS THE FAR SOUTH. THINKING THERE MAY BE A BREAK
BETWEEN THIS DEPARTING BATCH OF PCPN AND MORE DEVELOPMENT ALONG A
COOL FRONT DROPPING SOUTH OUT OF CANADA ON SUNDAY AFTERNOON.
HOWEVER LEFT SOME LOW CHANCES AROUND JUST IN CASE OF ANY LINGERING
LIGHT PCPN. THE COOL FRONT DROPS SOUTH OUT OF SOUTHERN MANITOBA ON
SUNDAY AFTERNOON AND THERE IS SOME WEAK INSTABILITY WITH IT. THIS
MAY BE ENOUGH TO GENERATE SOME THUNDER SO LEFT BETTER CHANCES FOR
THIS ACROSS THE NORTHERN FA. ANYTHING THAT FIRES ALONG THIS FRONT
SHOULD FALL APART IN THE EVENING. HIGH PRESSURE STILL BUILDS BACK
IN BEHIND THIS FRONT KEEPING MON AND TUE QUIET BUT COOL.
LONG TERM (TUE NIGHT-SAT)...
12Z GFS/12Z GEM/00Z ECMWF ALL IN REASONABLE AGREEMENT IN SHOWING
NEXT 500 MB TROUGH MOVING THRU THE AREA TUES NIGHT INTO WEDNESDAY
WITH ASSOCIATED COLD FRONT AND PRECIPITATION CHANCES. ECMWF A BIT
SLOWER THAN GFS...BUT OTHERWISE DECENT AGREEMENT SO CONFIDENCE WITH
SYSTEM A BIT HIGHER THAN NORMAL. COOLER AIR WILL MOVE WED NIGHT
INTO THURSDAY WITH LIKELY SOME WRAPAROUND STRATOCU IN COLD ADVECTION
ESP NE ND INTO NRN MN WHERE A FEW SHOWERS MAY DEVELOP ON THURSDAY.
HIGH PRESSURE WILL BRING CLEARING TO ALL AREAS THURS NIGHT INTO
SATURDAY. TEMPS WILL COOL TO BELOW NORMAL WED-FRI AS 850 MB TEMPS
DROP TO THE +2 TO +4C RANGE ON THURSDAY AND THEN RETURN CLOSE TO
NORMAL VALUES ON SATURDAY.
AVIATION...
THE LOWER LAYERS OF THE ATMOSPHERE WILL REMAIN QUITE DRY INTO SUNDAY
AS THE BULK OF THE RAIN AND LOWER LEVEL MOISTURE SLIDES JUST SOUTH
OF OUR AREA. EXCEPTION WILL BE FAR SOUTHEASTERN ND SOUTH OF FARGO
WHERE A PERIOD MVFR CIGS AND A STEADY RAIN IS LIKELY LATER TONIGHT
INTO SUNDAY MORNING. DID INCLUDE SOME -RA OVERNIGHT AT FAR TAF SITE
WITH A HIGH END VFR CIG AND ALSO GAVE A POSSIBILITY OF -RA AT DVL
TAF THIS EVENING. NO RAIN AT GFK/TVF/BJI TAF SITES THRU 18Z
SUN...BUT AFTER 18Z A COLD FRONT WILL PUSH INTO THE AREA AND MAY
TRIGGER A FEW SHRA/TSTMS ALONG IT. SOUTH WINDS WILL DIMINISH
TONIGHT AND THEN BECOME LIGHT AND VARIABLE BY 12Z SUN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
927 AM CDT FRI AUG 10 2012
.DISCUSSION...LATEST VISIBLE SATELLITE IMAGERY ALONG WITH REGIONAL
RADAR SHOWS A COUPLE SHORTWAVES APPROACHING/PROPAGATING THROUGH
WESTERN NORTH DAKOTA. THE FIRST WAS SEEN NEAR WATFORD CITY WITH AN
ISOLATED SHOWER IN FAR EASTERN DUNN COUNTY...WHICH HAS WEAKENED
AND DISSIPATED. A MORE SUBSTANTIAL AREA OF SHOWERS AND ISOLATED
THUNDERSTORMS WAS NOTED FROM GLASGOW SOUTH TO BILLINGS ASSOCIATED
WITH A SECOND SHORTWAVE. LATEST RADAR TRENDS SHOW SOME WEAKENING
AND THE LATEST HRRR MODEL HAS THIS AREA REACHING THE WESTERN
BORDER BY AROUND 18Z AND THEN INTO OUR SOUTHWEST ZONES THIS
AFTERNOON...BUT IN A MUCH WEAKER STATE THAN CURRENT. THIS WILL BRING
QUITE A BIT OF CLOUDINESS TO THE WEST LATER THIS MORNING AND HAVE
INCREASED CLOUD COVERAGE TO ACCOUNT FOR THIS. MAY HAVE TO LOWER
HIGH TEMPERATURES IN WEST IF CLOUDS REMAIN MOST OF THE AFTERNOON.
REST OF FORECAST REMAINS ON TRACK WITH SATURDAY BECOMING INCREASING
WET ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH UPWARDS OF
NEAR/AROUND AN INCH POSSIBLE IN MANY LOCALES.
&&
.AVIATION...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN
EASTERN MONTANA CONTINUE TO MOVE TOWARD THE WESTERN NORTH DAKOTA
BORDER. INDICATIONS ARE THIS AREA WILL WEAKEN INTO A SCATTERED
SHOWER REGIME THROUGH THE MORNING...HOWEVER WILL MONITOR THE
TRENDS AND MAY HAVE TO ADD A VCSH/VCTS IN KISN AND/OR KDIK IF THE
AREA HOLDS TOGETHER. OTHERWISE SHOWERS AND STORMS ARE EXPECTED TO
INCREASE IN COVERAGE AFTER 00Z TONIGHT...WITH MAIN IMPACTS AT
KISN/KDIK THROUGH 12Z SATURDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...RK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1136 PM EDT SAT AUG 11 2012
.SYNOPSIS...
AN UNSEASONABLY STRONG UPPER LEVEL LOW OVER THE LOWER GR 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 SUNDAY 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 SUNDAY MORNING THROUGH 6 PM SUNDAY/...
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 /SUNDAY 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 /04Z SUNDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS CONTINUE OVER MOST OF CENTRAL
PENNSYLVANIA...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.
AFTER MORNING FOG AND SOME STRATUS...MOST AREAS TO 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.
OUTLOOK...
MON...MAINLY VFR.
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
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1035 PM EDT SAT AUG 11 2012
.SYNOPSIS...
AN UNSEASONABLY STRONG UPPER LEVEL LOW OVER THE LOWER GR 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 SUNDAY 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 SUNDAY MORNING THROUGH 6 PM SUNDAY/...
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 /SUNDAY 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 /02Z SUNDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS EXIST OVER MOST OF CENTRAL PENNSYLVANIA...
WITH MVFR CONDITIONS CONFINED TO THE MOUNTAINS OF THE WEST AND
NORTH. RADAR AND SATELLITE TRENDS INDICATE THAT LOWER CLOUDS AND
EVEN A POTENTIAL FOR A FEW SHOWERS WILL PERSIST HERE INTO THE
NIGHTTIME HOURS AND LIKELY LOCK IN OVERNIGHT BELOW INVERSION.
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.
AFTER MORNING FOG AND SOME STRATUS...MOST AREAS TO 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.
OUTLOOK...
MON...MAINLY VFR.
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
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
537 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND SHOULD
GET HUNG UP ACROSS THE MOUNTAINS TONIGHT. THE FRONT IS EXPECTED TO
PUSH THROUGH LATE SATURDAY AND THEN SOUTH OF THE AREA ON SUNDAY.
HIGH PRESSURE WILL MOVE IN FOR THE EARLY PART OF NEXT WEEK.
MEANWHILE ANOTHER FRONT WILL APPROACH THE AREA BY MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 530 PM...A STRONG STORM HAS MOVED INTO RABUN COUNTY...AND A
LINE OF CONVECTION IS ORGANIZING OVER THE GREAT VALLEY OF TN.
HOWEVER...NOT MUCH IS HAPPENING OVER THE ERN FOOTHILLS AND PIEDMONT
ZONES ATTM AND I/VE CUT BACK POPS IN THOSE LOCATIONS FOR THE NEXT
COUPLE HOURS. THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT
CONVECTION WILL BECOME MORE WIDESPREAD THROUGH BOTH AN MCS MOVING
INTO THE NC MTNS AND CONVECTION DEVELOPING IN STRENGTHENING LLVL
CONVERGENCE ACROSS THE FOOTHILLS LATER THIS EVENING. AND THIS IS
REFLECTED WELL IN THE GRIDS.
AS OF MID AFTERNOON...VISIBLE SATELLITE IMAGERY SHOWS LOW CONVECTIVE
CLOUDS SCATTERING SUFFICIENTLY E OF THE BLUE RIDGE TO ALLOW HEATING
THAT HAS RAISED SFC-BASED CAPE INTO THE 1500-2000 J/KG RANGE ON THE
LAPS ANALYSIS. SHOWER ACTIVITY HAS DEVELOPED OVER THE CLT METRO AREA
AND ALONG THE BLUE RIDGE...WITH MORE ACTIVITY CLOSER TO THE FRONT
OVER THE CUMBERLAND PLATEAU. EXPECT SHOWERS AND STORMS TO CONTINUE
DEVELOPING AND BECOMING MORE NUMEROUS...MAINLY OVER THE MTNS AND
FOOTHILLS...THROUGH THE LATE AFTERNOON. SEVERE WEATHER REMAINS A
CONCERN WITH SOME DRY AIR ABOVE 500 MB...ALTHO IN GENERAL THE
SOUNDINGS DO NOT LOOK AS FAVORABLE AS YESTERDAY.
OVER THE NEXT 24 HOURS OR SO...THE MODELS ARE IN GOOD AGREEMENT WITH
THE EVOLUTION OF WEATHER FEATURES...AND IN PARTICULAR SHOW THE AXIS
OF THE UPPER TROF AND THE UPPER JET REMAINING TO OUR WEST. THIS WILL
ACT TO KEEP THE SURFACE FRONT HUNG UP PROBABLY OVER THE MTNS THROUGH
SATURDAY AFTERNOON. THE TREND...THEREFORE...IS TO HOLD ON TO MORE OF
A CHANCE OF SHOWER/TSTM ACTIVITY OVER A LARGER PART OF THE FCST AREA
THROUGH 00Z SUNDAY.
THE THREAT OF SEVERE STORMS WILL SLOWLY INCREASE AS BUOYANCY
AND DCAPE SLOWLY BECOME MORE FAVORABLE...WITH JUST ENOUGH SHEAR TO
PERHAPS ORGANIZE STORMS EARLY THIS EVENING. THE 4KM WRF DEVELOPS A
LINE OF STORMS OFF THE BLUE RIDGE AROUND 23Z WHILE THE HRRR BRINGS
THE LINE OF STORMS ACROSS TN AND INTO THE NC MTNS AROUND THAT TIME.
ABUNDANT LOW LEVEL MOISTURE AND ENUF UPPER FORCING WILL EXIST TO
WARRANT A LIKELY POP INTO THE EVENING HOURS. WILL KEEP POP IN THE
CHANCE RANGE OVERNIGHT AS ADDITIONAL STORMS COULD REDEVELOP AT ANY
TIME WITH THE SITUATION REMAINING UNCHANGED. TEMPS WILL REMAIN MILD.
ON SATURDAY...EXPECT THE FRONT TO BE HUNG UP OVER THE MTNS AT
SUNRISE. UNLESS EXTENSIVE CONVECTIVE DEBRIS PREVENTS IT...CONVECTION
SHOULD RE-FIRE EARLY IN THE DAY CLOSE TO THE FRONT AS IT DID TO OUR
WEST THIS PAST MORNING. UPPER DIVERGENCE...DPVA...AND PLENTY OF
MOISTURE SUGGEST ANOTHER POP IN THE LIKELY RANGE BY AFTERNOON OVER
THE PIEDMONT...AND A CHANCE UP TO THE BLUE RIDGE. A GUIDANCE BLEND
WAS USED FOR HIGH TEMPS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT FRIDAY...12Z GFS AND NAM STILL SOMEWHAT AT ODDS AS TO
HOW FAST THE FRONTAL BAND OF DEEP LAYER MOISTURE AND PRECIP WILL
EXIT THE FORECAST AREA OVER THE EAST. THE NAM STIL IS FASTER AND HAS
THE DEEP LAYER FRONTAL MOISTURE EAST OF THE AREA BY 00Z SUN...WHILE
THE GFS IS CONSIDERABLY SLOWER AND WETTER. THE SREF APPEARS TO
CONTINUE TO BE A GOOD COMPROMISE FOR THE SOLUTION. THE SREF KEEPS
PRECIP CHANCES OVER THE EASTERN MOST PART OF THE FORECAST AREA EARLY
ON SAT NIGHT...AND THEN MOVES THE MOISTURE/PRECIP EAST BY MIDNIGHT.
WILL ALSO SCATTER AND CLEAR THE CLOUDS FROM NW TO SE SAT NIGHT. HIGH
PRESSURE BUILDS OVER THE AREA ON SUN WHICH SHOULD PRODUCE A VERY
NICE DAY WITH DEWPOINTS MIXING OUT INTO THE 50S OVER THE MOUNTAINS
AND LOW 60S ELSEWHERE. THE HIGH SHIFTS EAST OF THE AREA ON
MONDAY...BUT ITS LINGERING INFLUENCE SHOULD ALLOW FOR ANOTHER DRY
DAY ON MONDAY. TEMPS ARE EXPECTED TO BE SLIGHTLY BELOW CLIMO ON SUN
AND NEAR CLIMO ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 130 PM EDT FRIDAY...A SOMEWHAT PROGRESSIVE PATTERN APPEARS TO BE
IN STORE DURING THE MEDIUM RANGE. THE UPPER AIR PATTERN WILL
GENERALLY FEATURE A MEAN TROUGH OVER THE EASTERN U.S. WITH
INDICATIONS FROM THE LATEST 12Z GFS OF BUILDING HEIGHTS TOWARD THE END
OF NEXT WEEK OVER THE EAST. LATEST HPC/GFS GUIDANCE SUGGESTS A WEAK
COLD FRONT WILL CROSS THE REGION ON TUE ALONG WITH SCATTERED
CONVECTION. THE GFS DRIVES THE FRONT SE OF THE AREA BY WED WITH HIGH
PRESSURE BUILDING IN THROUGH THU. THUS ONLY CLIMO TYPE POPS FOR
AFTERNOON CONVECTION IN THE MOUNTAINS WED AND THU. ANOTHER FRONT
APPROACHES THE AREA ON FRI AND PER HPC WILL FORECAST CHANCE TYPE
POPS. TEMPS SHOULD BE NEAR CLIMO THROUGH THE PERIOD.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...SCATTERED SHOWERS DEVELOPING RAPIDLY OVER THE WRN PIEDMONT
WHILE CLOUD BASES REMAIN MVFR. THIS SHOULD CONTINUE WITH A SLOW RISE
IN THE LCL THROUGH EARLY AFTERNOON...SUCH THAT CONDITIONS SHOULD
BECOME VFR BY 20Z. LOW CLOUDS WILL CONTINUE...HOWEVER...THROUGH THE
REST OF THE DAYLIGHT HOURS GIVEN THE PLENTIFUL LOW LEVEL MOISTURE.
THE LATEST GUIDANCE SUGGESTS THE BEST CHANCE FOR ANOTHER ROUND OF
THUNDERSTORMS WILL BE EARLY THIS EVENING. THERE IS ENUF FORCING TO
SUGGEST THAT STORMS ARE LIKELY...SO THE TARGET WINDOW OF 01Z TO 04Z
HAS BEEN ESTABLISHED. SOME SHOWERS COULD CONTINUE OVERNIGHT WITH THE
ACTUAL FRONT HUNG UP TO THE WEST. LOW CLOUDS SHOULD RETURN LATE
TONIGHT...RESULTING IN AT LEAST AN MVFR CEILING AFTER 11Z. MORE LOW
CLOUDS ARE POSSIBLE AGAIN SATURDAY MORNING WITH THE FRONT HUNG UP
OVER THE MTNS.
ELSEWHERE...LOW CLOUDS CONTINUE TO SCATTER OUT EARLY THIS EVENING...
WHICH WILL FINALLY ALLOW FOR SOME DESTABILIZATION. SHOWERS WILL
CONTINUE TO DEVELOP ACROSS THE MTNS THROUGH 22Z AND THEN PUSH EAST
THROUGH THE EARLY EVENING. RETURN TO LOW MVFR/IFR CIGS TONIGHT AS
FRONT SLOWS...IFR VSBY POSSIBLY MAINLY ACROSS KHKY AND KAVL WHERE
DRY AIR ALOFT WORKS IN.
OUTLOOK...A COLD FRONT WILL SLOWLY CROSS THE AREA LATE SATURDAY...
WITH DRIER HIGH PRES BUILDING IN FROM THE W THE LATTER HALF OF THE
WEEKEND. WEAK HIGH PRESSURE WILL LINGER THROUGH EARLY NEXT 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...PM
NEAR TERM...MCAVOY
SHORT TERM...LG
LONG TERM...LG
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
241 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND SHOULD
GET HUNG UP ACROSS THE MOUNTAINS TONIGHT. THE FRONT IS EXPECTED TO
PUSH THROUGH LATE SATURDAY AND THEN SOUTH OF THE AREA ON SUNDAY.
HIGH PRESSURE WILL MOVE IN FOR THE EARLY PART OF NEXT WEEK.
MEANWHILE ANOTHER FRONT WILL APPROACH THE AREA BY MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF MID AFTERNOON...VISIBLE SATELLITE IMAGERY SHOWS LOW CONVECTIVE
CLOUDS SCATTERING SUFFICIENTLY E OF THE BLUE RIDGE TO ALLOW HEATING
THAT HAS RAISED SFC-BASED CAPE INTO THE 1500-2000 J/KG RANGE ON THE
LAPS ANALYSIS. SHOWER ACTIVITY HAS DEVELOPED OVER THE CLT METRO AREA
AND ALONG THE BLUE RIDGE...WITH MORE ACTIVITY CLOSER TO THE FRONT
OVER THE CUMBERLAND PLATEAU. EXPECT SHOWERS AND STORMS TO CONTINUE
DEVELOPING AND BECOMING MORE NUMEROUS...MAINLY OVER THE MTNS AND
FOOTHILLS...THROUGH THE LATE AFTERNOON. SEVERE WEATHER REMAINS A
CONCERN WITH SOME DRY AIR ABOVE 500 MB...ALTHO IN GENERAL THE
SOUNDINGS DO NOT LOOK AS FAVORABLE AS YESTERDAY.
OVER THE NEXT 24 HOURS OR SO...THE MODELS ARE IN GOOD AGREEMENT WITH
THE EVOLUTION OF WEATHER FEATURES...AND IN PARTICULAR SHOW THE AXIS
OF THE UPPER TROF AND THE UPPER JET REMAINING TO OUR WEST. THIS WILL
ACT TO KEEP THE SURFACE FRONT HUNG UP PROBABLY OVER THE MTNS THROUGH
SATURDAY AFTERNOON. THE TREND...THEREFORE...IS TO HOLD ON TO MORE OF
A CHANCE OF SHOWER/TSTM ACTIVITY OVER A LARGER PART OF THE FCST AREA
THROUGH 00Z SUNDAY.
THE THREAT OF SEVERE STORMS WILL SLOWLY INCREASE AS BUOYANCY
AND DCAPE SLOWLY BECOME MORE FAVORABLE...WITH JUST ENOUGH SHEAR TO
PERHAPS ORGANIZE STORMS EARLY THIS EVENING. THE 4KM WRF DEVELOPS A
LINE OF STORMS OFF THE BLUE RIDGE AROUND 23Z WHILE THE HRRR BRINGS
THE LINE OF STORMS ACROSS TN AND INTO THE NC MTNS AROUND THAT TIME.
ABUNDANT LOW LEVEL MOISTURE AND ENUF UPPER FORCING WILL EXIST TO
WARRANT A LIKELY POP INTO THE EVENING HOURS. WILL KEEP POP IN THE
CHANCE RANGE OVERNIGHT AS ADDITIONAL STORMS COULD REDEVELOP AT ANY
TIME WITH THE SITUATION REMAINING UNCHANGED. TEMPS WILL REMAIN MILD.
ON SATURDAY...EXPECT THE FRONT TO BE HUNG UP OVER THE MTNS AT
SUNRISE. UNLESS EXTENSIVE CONVECTIVE DEBRIS PREVENTS IT...CONVECTION
SHOULD RE-FIRE EARLY IN THE DAY CLOSE TO THE FRONT AS IT DID TO OUR
WEST THIS PAST MORNING. UPPER DIVERGENCE...DPVA...AND PLENTY OF
MOISTURE SUGGEST ANOTHER POP IN THE LIKELY RANGE BY AFTERNOON OVER
THE PIEDMONT...AND A CHANCE UP TO THE BLUE RIDGE. A GUIDANCE BLEND
WAS USED FOR HIGH TEMPS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT FRIDAY...12Z GFS AND NAM STILL SOMEWHAT AT ODDS AS TO
HOW FAST THE FRONTAL BAND OF DEEP LAYER MOISTURE AND PRECIP WILL
EXIT THE FORECAST AREA OVER THE EAST. THE NAM STIL IS FASTER AND HAS
THE DEEP LAYER FRONTAL MOISTURE EAST OF THE AREA BY 00Z SUN...WHILE
THE GFS IS CONSIDERABLY SLOWER AND WETTER. THE SREF APPEARS TO
CONTINUE TO BE A GOOD COMPROMISE FOR THE SOLUTION. THE SREF KEEPS
PRECIP CHANCES OVER THE EASTERN MOST PART OF THE FORECAST AREA EARLY
ON SAT NIGHT...AND THEN MOVES THE MOISTURE/PRECIP EAST BY MIDNIGHT.
WILL ALSO SCATTER AND CLEAR THE CLOUDS FROM NW TO SE SAT NIGHT. HIGH
PRESSURE BUILDS OVER THE AREA ON SUN WHICH SHOULD PRODUCE A VERY
NICE DAY WITH DEWPOINTS MIXING OUT INTO THE 50S OVER THE MOUNTAINS
AND LOW 60S ELSEWHERE. THE HIGH SHIFTS EAST OF THE AREA ON
MONDAY...BUT ITS LINGERING INFLUENCE SHOULD ALLOW FOR ANOTHER DRY
DAY ON MONDAY. TEMPS ARE EXPECTED TO BE SLIGHTLY BELOW CLIMO ON SUN
AND NEAR CLIMO ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 130 PM EDT FRIDAY...A SOMEWHAT PROGRESSIVE PATTERN APPEARS TO BE
IN STORE DURING THE MEDIUM RANGE. THE UPPER AIR PATTERN WILL
GENERALLY FEATURE A MEAN TROUGH OVER THE EASTERN U.S. WITH
INDICATIONS FROM THE LATEST 12Z GFS OF BUILDING HEIGHTS TOWARD THE END
OF NEXT WEEK OVER THE EAST. LATEST HPC/GFS GUIDANCE SUGGESTS A WEAK
COLD FRONT WILL CROSS THE REGION ON TUE ALONG WITH SCATTERED
CONVECTION. THE GFS DRIVES THE FRONT SE OF THE AREA BY WED WITH HIGH
PRESSURE BUILDING IN THROUGH THU. THUS ONLY CLIMO TYPE POPS FOR
AFTERNOON CONVECTION IN THE MOUNTAINS WED AND THU. ANOTHER FRONT
APPROACHES THE AREA ON FRI AND PER HPC WILL FORECAST CHANCE TYPE
POPS. TEMPS SHOULD BE NEAR CLIMO THROUGH THE PERIOD.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...SCATTERED SHOWERS DEVELOPING RAPIDLY OVER THE WRN PIEDMONT
WHILE CLOUD BASES REMAIN MVFR. THIS SHOULD CONTINUE WITH A SLOW RISE
IN THE LCL THROUGH EARLY AFTERNOON...SUCH THAT CONDITIONS SHOULD
BECOME VFR BY 20Z. LOW CLOUDS WILL CONTINUE...HOWEVER...THROUGH THE
REST OF THE DAYLIGHT HOURS GIVEN THE PLENTIFUL LOW LEVEL MOISTURE.
THE LATEST GUIDANCE SUGGESTS THE BEST CHANCE FOR ANOTHER ROUND OF
THUNDERSTORMS WILL BE EARLY THIS EVENING. THERE IS ENUF FORCING TO
SUGGEST THAT STORMS ARE LIKELY...SO THE TARGET WINDOW OF 01Z TO 04Z
HAS BEEN ESTABLISHED. SOME SHOWERS COULD CONTINUE OVERNIGHT WITH THE
ACTUAL FRONT HUNG UP TO THE WEST. LOW CLOUDS SHOULD RETURN LATE
TONIGHT...RESULTING IN AT LEAST AN MVFR CEILING AFTER 11Z. MORE LOW
CLOUDS ARE POSSIBLE AGAIN SATURDAY MORNING WITH THE FRONT HUNG UP
OVER THE MTNS.
ELSEWHERE...LOW CLOUDS CONTINUE TO SCATTER OUT EARLY THIS EVENING...
WHICH WILL FINALLY ALLOW FOR SOME DESTABILIZATION. SHOWERS WILL
CONTINUE TO DEVELOP ACROSS THE MTNS THROUGH 22Z AND THEN PUSH EAST
THROUGH THE EARLY EVENING. RETURN TO LOW MVFR/IFR CIGS TONIGHT AS
FRONT SLOWS...IFR VSBY POSSIBLY MAINLY ACROSS KHKY AND KAVL WHERE
DRY AIR ALOFT WORKS IN.
OUTLOOK...A COLD FRONT WILL SLOWLY CROSS THE AREA LATE SATURDAY...
WITH DRIER HIGH PRES BUILDING IN FROM THE W THE LATTER HALF OF THE
WEEKEND. WEAK HIGH PRESSURE WILL LINGER THROUGH EARLY NEXT 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...PM
NEAR TERM...PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...PM
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1052 PM CDT SAT AUG 11 2012
.DISCUSSION.../ISSUED AT 845 PM CDT/
SHORT WAVE DTROPPING SOUTHEAST OUT OF ND AND BOTH HRRR AND NAM SEEM
TO HAVE BEST HANDLE ON TIMING AND LOCATION OF RAIN. HAVE SPED UP
TIMING AND INCREASED POPS ACROSS EASTERN CWA AS WAVE DROPS DOWN
WHILE TRIMMED BACK POPS WEST OF A HON-PKS LINE AS MOST OF RAIN
TONIGHT WILL BE FURTHER EAST OF INVERTED TROF. IN FACT...THE BULK OF
RAIN WEST OF I29 MAY BE OVER AFTER 08Z WITH MORE DEFINED AREA OF
WIDESPREAD RAIN TO THE EAST. DID MAKE SOME TWEAKS TO LOWS AND POPS.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
A STRENGTHENING LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE INTO THE
AREA TONIGHT INTO SUNDAY. OCCASIONAL SHOWERS ARE LIKELY MUCH OF THE
NIGHT WITH THIS SYSTEM...WITH MOST OF THE ACTIVITY FOCUSED EAST OF
INTERSTATE 29. COULD SEE SOME LOCAL MVFR RESTRICTIONS IN ANY OF THE
HEAVIER SHOWERS...MAINLY ACROSS SOUTHWEST MINNESOTA. OTHERWISE VFR
CONDITIONS SHOULD PREVAIL WITH RATHER HIGH CLOUD BASES THROUGH THE
NIGHT. WINDS WILL TURN NORTHWESTERLY BEHIND THE LOW PRESSURE SYSTEM
ON SUNDAY AND BECOME BREEZY...FIRST AT KHON DURING THE
MORNING...MAKING IT TO KFSD AND KSUX BY AFTERNOON. EXPECT LOW
STRATUS TO FORM NORTH OF THE LOW AND AS THE WINDS SHIFT BEHIND THE
LOW...WITH MVFR CIGS AT KHON BY MID MORNING. AREAS FURTHER SOUTH AND
EAST SHOULD SEE THE STRATUS LOWER DURING THE AFTERNOON AND EVENING
HOURS. THINKING WIDESPREAD MVFR CIGS WILL BE POSSIBLE WITH THIS
STRATUS...WITH EVEN SOME AREAS OF IFR POSSIBLE THROUGH MIDNIGHT.
BAND OF HEAVIER SHOWERS MAY CONTINUE ACROSS SOUTHWEST MINNESOTA INTO
SUNDAY...WITH JUST LIGHTER ACTIVITY OR DRY CONDITIONS ELSEWHERE.
COULD ALSO SEE SOME SCATTERED SHOWERS AND THUNDERSTORMS REFORM AHEAD
OF THE LOW SUNDAY LATE MORNING INTO THE AFTERNOON...BEST CHANCE
ACROSS NORTHWEST IOWA. /CHENARD
&&
.PREVIOUS DISCUSSION.../ISSUED AT 300 PM CDT/
STRONG UPPER WAVE OVER EASTERN MT THIS AFTERNOON WILL DIVE SOUTHEAST
THROUGH THE DAKOTAS TONIGHT AND THEN THROUGH IOWA AND SOUTHERN MN ON
SUNDAY. ALREADY SEEING WIDESPREAD SHOWER ACTIVITY IN THE NORTHERN
PLAINS IN THE WARM ADVECTION AHEAD OF THIS SYSTEM. SHOWERS AND A FEW
THUNDERSTORMS WILL SPREAD FROM WEST TO EAST ACROSS THE FORECAST AREA
THIS EVENING AND OVERNIGHT...AND LINGER THROUGH MOST OF SUNDAY.
HIGHEST POPS WILL BE IN THE NORTH TONIGHT AND THE NORTHEAST ON
SUNDAY ASSOCIATED WITH THE STRONGEST FRONTOGENESIS...BUT SOME RAIN
IS LIKELY PRETTY MUCH OVER THE WHOLE AREA. BEST CHANCES FOR THUNDER
WILL BE IN THE FAR WEST EARLY THIS EVENING...AND THEN IN THE EASTERN
PORTIONS OF NORTHWEST IOWA SUNDAY AFTERNOON...BUT NOT EXCITED ABOUT
ANY SEVERE POSSIBILITIES DUE TO LIMITED DEEP INSTABILITY. RAINFALL
TOTALS OF 0.5 TO 1.0 INCH ARE EXPECTED FOR MOST OF THE AREA.
FORCING WANES PRETTY QUICKLY ON SUNDAY EVENING AS THE UPPER LEVEL
SHORTWAVE PULLS OFF TO THE EAST OVERNIGHT...SO WILL SEE SHOWER
ACTIVITY THROUGH OUR EASTERN CWA DIMINISH FROM WEST TO EAST DURING
THAT TIME FRAME. COOLER AIR WILL FILTER IN BEHIND THE EXITING SYSTEM
WITH LOWS IN THE MID TO UPPER 50S.
MONDAY LOOKS TO BE A PLEASANT DAY AS SURFACE HIGH PRESSURE BUILDS
INTO THE REGION UNDER A NORTHWESTERLY UPPER LEVEL FLOW. WITH
ABUNDANT SUNSHINE IT WILL BE A WARMER DAY THAN SUNDAY...WITH HIGHS
IN THE MID/UPPER 70S NORTHEAST TO THE LOWER 80S THROUGH THE MISSOURI
RIVER CORRIDOR. THE SURFACE RIDGE BEGINS TO MOVE TO THE EAST ON
MONDAY NIGHT...WITH LOW LEVEL WARM ADVECTION COMMENCING IN OUR WEST
AS WINDS TAKE ON A SOUTHERLY COMPONENT...AND LOWS WILL BE CLOSE TO
60 THROUGH THE JAMES RIVER VALLEY THROUGH THE LOWER MISSOURI RIVER
CORRIDOR...TO MID 50S OVER SOUTHWESTERN MINNESOTA INTO PORTIONS OF
NORTHWESTERN IOWA.
A TAD WARMER ON TUESDAY WITH THERMAL PROFILES WARMING JUST A
BIT...AND HIGHS IN THE UPPER 80S OVER SOUTH CENTRAL SOUTH DAKOTA TO
AROUND 80 IN OUR EASTERN AREAS. A SURFACE TROUGH APPROACHES FROM THE
WEST ON TUESDAY NIGHT...WITH LOWER TO MIDLEVEL THETA E ADVECTION
INCREASING IN OUR WEST AS THE LOW LEVEL JET CRANKS UP FROM CENTRAL
NEBRASKA INTO SOUTH CENTRAL AND EASTERN SOUTH DAKOTA OVERNIGHT. WITH
THAT...SCATTERED THUNDERSTORMS MAY DEVELOP IN OUR NORTHWEST DURING
THE NIGHT.
IN THE EXTENDED...THE SURFACE TROUGH/FRONTAL BOUNDARY WORKS SLOWLY
ACROSS THE AREA FOR WEDNESDAY INTO THURSDAY...AND WITH DECENT MODEL
AGREEMENT THERE LOOKS TO BE A PRETTY GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS OUR EAST ON WEDNESDAY NIGHT. OUT AHEAD OF THE
SYSTEM...IT WILL BE WARM ON WEDNESDAY WITH HIGHS IN THE LOWER 80S
NORTH TO UPPER 80S THROUGH THE MISSOURI RIVER CORRIDOR. MUCH COOLER
ON THURSDAY IN A COLD AIR ADVECTION REGIME ON THE BACKSIDE OF THE
SYSTEM...WITH HIGHS LOWER TO MID 70S. DRYING OUT FOR THE END OF NEXT
WEEK AS HIGH PRESSURE BUILDS BACK INTO THE REGION. BELOW NORMAL
TEMPERATURES LOOK TO REMAIN FOR FRIDAY...THEN CLIMBING BACK TO NEAR
NORMAL FOR SATURDAY AS A WESTERN U.S. UPPER LEVEL RIDGE OOZES
EASTWARD.
&&
.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
845 PM CDT SAT AUG 11 2012
.DISCUSSION.../ISSUED AT 845 PM CDT/
SHORT WAVE DTROPPING SOUTHEAST OUT OF ND AND BOTH HRRR AND NAM SEEM
TO HAVE BEST HANDLE ON TIMING AND LOCATION OF RAIN. HAVE SPED UP
TIMING AND INCREASED POPS ACROSS EASTERN CWA AS WAVE DROPS DOWN
WHILE TRIMMED BACK POPS WEST OF A HON-PKS LINE AS MOST OF RAIN
TONIGHT WILL BE FURTHER EAST OF INVERTED TROF. IN FACT...THE BULK OF
RAIN WEST OF I29 MAY BE OVER AFTER 08Z WITH MORE DEFINED AREA OF
WIDESPREAD RAIN TO THE EAST. DID MAKE SOME TWEAKS TO LOWS AND POPS.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
A STRENGTHENING LOW PRESSURE WILL CONTINUE TO MOVE INTO THE AREA
TONIGHT INTO SUNDAY. OCCASIONAL SHOWERS ARE LIKELY MUCH OF THE
NIGHT WITH THIS SYSTEM. COULD SEE A BAND OF HEAVIER SHOWERS AND
EMBEDDED THUNDER FORM LATER THIS EVENING...MOST LIKELY ACROSS THE
NORTHERN HALF OF THE AREA. COULD SEE SOME MVFR RESTRICTIONS IN ANY
OF THESE HEAVIER SHOWERS. OTHERWISE VFR CONDITIONS SHOULD PREVAIL
WITH RATHER HIGH CLOUD BASES THROUGH THE NIGHT. WINDS WILL TURN
NORTHWESTERLY BEHIND THE LOW PRESSURE SYSTEM ON SUNDAY...FIRST AT
KHON DURING THE MORNING...MAKING IT TO KFSD AND KSUX BY AFTERNOON OR
EARLY EVENING. EXPECT LOW STRATUS TO FORM AS THE WINDS SHIFT BEHIND
THE LOW...WITH MVFR CIGS AT KHON BY MID TO LATE MORNING. AREAS
FURTHER SOUTH AND EAST MAY KEEP CIGS ABOVE MVFR THROUGH 0Z. BAND OF
HEAVIER SHOWERS MAY CONTINUE ACROSS SOUTHWEST MINNESOTA INTO
SUNDAY...WITH JUST LIGHTER ACTIVITY ELSEWHERE. COULD ALSO SEE SOME
SCATTERED SHOWERS AND THUNDERSTORMS REFORM AHEAD OF THE LOW SUNDAY
LATE MORNING INTO THE AFTERNOON...BEST CHANCE FROM SIOUX FALLS SOUTH
AND EAST INTO NORTHWEST IOWA. /CHENARD
&&
.PREVIOUS DISCUSSION.../ISSUED AT 300 PM CDT/
STRONG UPPER WAVE OVER EASTERN MT THIS AFTERNOON WILL DIVE SOUTHEAST
THROUGH THE DAKOTAS TONIGHT AND THEN THROUGH IOWA AND SOUTHERN MN ON
SUNDAY. ALREADY SEEING WIDESPREAD SHOWER ACTIVITY IN THE NORTHERN
PLAINS IN THE WARM ADVECTION AHEAD OF THIS SYSTEM. SHOWERS AND A FEW
THUNDERSTORMS WILL SPREAD FROM WEST TO EAST ACROSS THE FORECAST AREA
THIS EVENING AND OVERNIGHT...AND LINGER THROUGH MOST OF SUNDAY.
HIGHEST POPS WILL BE IN THE NORTH TONIGHT AND THE NORTHEAST ON
SUNDAY ASSOCIATED WITH THE STRONGEST FRONTOGENESIS...BUT SOME RAIN
IS LIKELY PRETTY MUCH OVER THE WHOLE AREA. BEST CHANCES FOR THUNDER
WILL BE IN THE FAR WEST EARLY THIS EVENING...AND THEN IN THE EASTERN
PORTIONS OF NORTHWEST IOWA SUNDAY AFTERNOON...BUT NOT EXCITED ABOUT
ANY SEVERE POSSIBILITIES DUE TO LIMITED DEEP INSTABILITY. RAINFALL
TOTALS OF 0.5 TO 1.0 INCH ARE EXPECTED FOR MOST OF THE AREA.
FORCING WANES PRETTY QUICKLY ON SUNDAY EVENING AS THE UPPER LEVEL
SHORTWAVE PULLS OFF TO THE EAST OVERNIGHT...SO WILL SEE SHOWER
ACTIVITY THROUGH OUR EASTERN CWA DIMINISH FROM WEST TO EAST DURING
THAT TIME FRAME. COOLER AIR WILL FILTER IN BEHIND THE EXITING SYSTEM
WITH LOWS IN THE MID TO UPPER 50S.
MONDAY LOOKS TO BE A PLEASANT DAY AS SURFACE HIGH PRESSURE BUILDS
INTO THE REGION UNDER A NORTHWESTERLY UPPER LEVEL FLOW. WITH
ABUNDANT SUNSHINE IT WILL BE A WARMER DAY THAN SUNDAY...WITH HIGHS
IN THE MID/UPPER 70S NORTHEAST TO THE LOWER 80S THROUGH THE MISSOURI
RIVER CORRIDOR. THE SURFACE RIDGE BEGINS TO MOVE TO THE EAST ON
MONDAY NIGHT...WITH LOW LEVEL WARM ADVECTION COMMENCING IN OUR WEST
AS WINDS TAKE ON A SOUTHERLY COMPONENT...AND LOWS WILL BE CLOSE TO
60 THROUGH THE JAMES RIVER VALLEY THROUGH THE LOWER MISSOURI RIVER
CORRIDOR...TO MID 50S OVER SOUTHWESTERN MINNESOTA INTO PORTIONS OF
NORTHWESTERN IOWA.
A TAD WARMER ON TUESDAY WITH THERMAL PROFILES WARMING JUST A
BIT...AND HIGHS IN THE UPPER 80S OVER SOUTH CENTRAL SOUTH DAKOTA TO
AROUND 80 IN OUR EASTERN AREAS. A SURFACE TROUGH APPROACHES FROM THE
WEST ON TUESDAY NIGHT...WITH LOWER TO MIDLEVEL THETA E ADVECTION
INCREASING IN OUR WEST AS THE LOW LEVEL JET CRANKS UP FROM CENTRAL
NEBRASKA INTO SOUTH CENTRAL AND EASTERN SOUTH DAKOTA OVERNIGHT. WITH
THAT...SCATTERED THUNDERSTORMS MAY DEVELOP IN OUR NORTHWEST DURING
THE NIGHT.
IN THE EXTENDED...THE SURFACE TROUGH/FRONTAL BOUNDARY WORKS SLOWLY
ACROSS THE AREA FOR WEDNESDAY INTO THURSDAY...AND WITH DECENT MODEL
AGREEMENT THERE LOOKS TO BE A PRETTY GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS OUR EAST ON WEDNESDAY NIGHT. OUT AHEAD OF THE
SYSTEM...IT WILL BE WARM ON WEDNESDAY WITH HIGHS IN THE LOWER 80S
NORTH TO UPPER 80S THROUGH THE MISSOURI RIVER CORRIDOR. MUCH COOLER
ON THURSDAY IN A COLD AIR ADVECTION REGIME ON THE BACKSIDE OF THE
SYSTEM...WITH HIGHS LOWER TO MID 70S. DRYING OUT FOR THE END OF NEXT
WEEK AS HIGH PRESSURE BUILDS BACK INTO THE REGION. BELOW NORMAL
TEMPERATURES LOOK TO REMAIN FOR FRIDAY...THEN CLIMBING BACK TO NEAR
NORMAL FOR SATURDAY AS A WESTERN U.S. UPPER LEVEL RIDGE OOZES
EASTWARD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1158 PM CDT THU AUG 9 2012
.UPDATE...FOR 06Z AVIATION DISCUSSION.
&&
.AVIATION...06Z AVIATION DISCUSSION.
UNCERTAINTIES...SFC FRONTAL MOVEMENT IMPACTS. AS SFC FRONT MOVES
CLOSER/EVENTUALLY THRU CKV/BNA...EXPECT SOME MOISTURE POOLING IN
ITS VICINITY...MENTIONED MVFR FOG/CEILINGS...TEMPO IFR CSV...BUT
EVEN WITH POSSIBLE SHORT WAVE PASSAGE IN UPPER LEVEL FLOW AIDING...
WILL JUST MENTION VCSH AT CKV/BNA. FRONT SHOULD BE W OF CSV THRU
AROUND 10/18Z...AND BELIEVE WITH DIURNAL INFLUENCES KICKING IN...
THAT CB/VCTS TSTM CSV APPROPRIATE. A DRYING AIRMASS SHOULD ESTABLISH
ITSELF ACROSS THE MID STATE BY 11/00Z TO SUPPORT SKC CONDITIONS.
&&
.PREV DISCUSSION.../ISSUED 1011 PM CDT THU AUG 9 2012/
UPDATE...
OTHER THAN THE ISOL CONVECTION OVER WESTERN MIDDLE TN...NOT MUCH
GOING ON. BOUNDARY STILL LOCATED A GOOD DISTANCE TO OUR NW.
NUMERICAL POPS ARE QUITE LOW THROUGH 12Z. HRRR NOW SHOWING SOME
REDEVELOPMENT WITH THE FRONTAL BOUNDARY AFT 08Z OR SO. PRESSURE
RISES ARE FAIRLY STRONG NORTH OF THE FRONTAL BOUNDARY.
THUS...BOUNDARY SHOULD STILL BE ON THE APPROACH THROUGH 12Z.
WILL GO AHEAD AND LOWER POPS TO THE 30-40 PERCENT RANGE FOR THE
DURATION. HRRR DOES MAKE A COMEBACK WITH THE CONVECTION BUT
PRIMARILY IS SERVING AS THE LONE MODEL...AND EVEN IF THE HRRR PANS
OUT...THE ACTIVITY DOES NOT LOOK ALL THAT ORGANIZED.
FOR THE UPDATE WILL LOWER POPS. UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 703 PM CDT THU AUG 9 2012/
UPDATE...FOR 00Z AVIATION DISCUSSION.
AVIATION...00Z AVIATION DISCUSSION.
UNCERTAINTIES...SFC FRONTAL MOVEMENT IMPACTS. CONVECTION TO OUR
NW AHEAD OF FRONT MAINLY DISSIPATED...AND WITH AN OVERALL DRIER
AIRMASS IN PLACE ACROSS THE MID STATE PER MORNING`S
CONVECTION...PCPN CHANCES SLIGHT AT BEST THRU 10/10Z AND WILL NOT
MENTION. AS SFC FRONT MOVES CLOSER/EVENTUALLY THRU
CKV/BNA...EXPECT SOME MOISTURE POOLING IN ITS VICINITY...MENTIONED
MVFR FOG/CEILINGS...TEMPO IFR CSV...BUT EVEN WITH POSSIBLE SHORT
WAVE PASSAGE IN UPPER LEVEL FLOW AIDING...JUST DOUBT WITH ANY
DIURNAL INFLUENCES NOT YET ESTABLISHED...PCPN WILL OCCUR. FRONT
SHOULD BE W OF CSV THRU AROUND 10/18Z...AND BELIEVE WITH DIURNAL
INFLUENCES KICKING IN...THAT CB/VCTS TSTM CSV APPROPRIATE.
PREV DISCUSSION.../ISSUED 602 PM CDT THU AUG 9 2012/
UPDATE...
NOT IMPRESSED WITH THE CHANCES FOR CONVECTION OVERNIGHT. ONLY
BULLISH TRENDS I SEE ARE WITH THE WRF AND THE FROPA WHICH IS
EXPECTED AT 12Z. OTW...UPPER DYNAMICS LOOKING WEAK WITH AN OVERALL
DECREASE IN MOISTURE DEPTH FROM 00Z TO 06Z. HRRR SHOWS ZILCH
THROUGH 6Z AND UPPER DIVERGENCE QUITE WEAK THROUGH 12Z ON THE GFS
AND NAM. I WILL GO AHEAD AND UPDATE GRIDS AD KNOCK POPS DOWN
PRIOR TO 06Z. AFT 06Z...WILL KEEP THE LIKELY POPS GOING ACROSS THE
NORTH BUT THIS MAY NEED A DOWNWARD YANK AS WELL LATER IN THIS
SHIFT.
REMAINDER OF FCST LOOKS TO BE IN GOOD SHAPE. NO MENTION OF FOG
CURRENTLY AND I SEE NO REASON TO ADD ANY AS TOVERS REMAIN NEAR TO
ABOVE 0. MIN TEMP FCST LOOKS TO BE IN GOOD SHAPE. UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 340 PM CDT THU AUG 9 2012/
SHORT TERM...SHOWERS AND CLOUDS THAT STILL LINGERED ALONG THE
CUMBERLAND PLATEAU AT MID-AFTERNOON WERE HELPING TO PRODUCE A
SIGNIFICANT TEMPERATURE GRADIENT ACROSS THE MID STATE. AT 300
PM...TEMPERATURES RANGED FROM THE UPPER 60S AT CSV TO THE UPPER
80S OVER OUR MOST WESTERN COUNTIES.
WITH SHOWERS DEPARTING OUR AREA, FROM THE PLATEAU, WE NOW TURN OUR
EYES TO THE WEST, WHERE NEW THUNDERSTORMS WERE POPPING UP IN THE
AFTERNOON HEAT, OVER SOUTHWESTERN KENTUCKY. THESE STORMS WERE ALSO
OCCURRING ALONG THE EDGE OF A BAND OF MID-T0-UPPER LEVEL DRYING
THAT EXTENDED FROM SOUTHERN PARTS OF INDIANA AND ILLINOIS, ACROSS
SOUTHEAST MISSOURI INTO CENTRAL ARKANSAS. WITH THE POSSIBILITY OF
DRY AIR ENTRAINMENT AT THE MID LEVELS, EXPECT SOME GUSTY
DOWNBURSTS TO BE POSSIBLE WITH THESE STORMS AS THEY ADVANCE INTO
NORTHWESTERN MIDDLE TENNESSEE LATE THIS AFTERNOON AND EVENING.
AFTER THE INITIAL CONVECTION THIS EVENING, THAT DEVELOPS MAINLY
OVER THE NORTHWEST, BELIEVE WE WILL SEE MORE THUNDERSTORM
DEVELOPMENT LATER TONIGHT, AS UPPER TROUGH DEEPENS OVER THE OHIO
RIVER VALLEY, ENERGIZING THE SLEEPY STATIONARY FRONT JUST WEST OF
PADUCAH, AND BRINGING IT EASTWARD AS A COLD FRONT.
EXPECT THE COLD FRONT TO BE NEAR A BWG-BNA-WAYNESBORO LINE BY 12Z
FRIDAY, PUSHING TO NR A MSL-LIVINGSTON LINE BY 18Z, AND OFF THE
CUMBERLAND PLATEAU BY LATE FRIDAY AFTERNOON.
SPC HAS ALL OF OUR AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS
THROUGH 12Z FRIDAY, AS THE FRONT PUSHES IN, AND EXPECT TO SEE
SIMILAR STORMS TO THE ONES WE HAD THIS MORNING...VERY WET AND
JUICY (WITH TORRENTIAL DOWNPOURS) ALONG WITH THE POSSIBILITY FOR
STRONG, GUSTY DOWNBURST WINDS.
EXPECT SHOWERS AND STORMS TO FINALLY PUSH EAST OF THE MID STATE FRIDAY
EVENING, WITH SEVERAL DAYS OF DRY AND AUTUMN-LIKE CONDITIONS TO
FOLLOW OVER THE WEEKEND. EXPECT AFTERNOON DEW POINTS IN THE 50S
BOTH SATURDAY AND SUNDAY, WITH DAYTIME HIGHS MAINLY IN THE MIDDLE
80S. MANY PLACES WILL LIKELY SEE LOW TEMPERATURES DROP INTO THE
MID TO UPPER 50S SUNDAY MORNING.
LONG TERM...AFTER OUR DRY SPELL OVER THE WEEKEND, EXPECT
NORTHWEST FLOW TO BECOME MORE ZONAL, WITH TWO OR THREE UPPER LEVEL
SHORTWAVES LIKELY TO TRAVERSE THE AREA NEXT WEEK. THE TIMING OF
THESE IMPULSES, OF COURSE, IS VERY DIFFICULT. IT`S ALSO DIFFICULT
TO KNOW HOW MUCH SHRA/TSRA ACTIVITY EACH ONE WITH BRING WITH IT.
THEREFORE, HAVE PAINTED POPS WITH A BROAD BRUSH FOR MOST OF NEXT
WEEK, WITH A 20% POP MAKING REPEATED ONSTAGE APPEARANCES.
TEMPERATURES WILL WARM BACK TO AROUND 90 DEGREES OR IN THE LOWER
90S FOR AREAS WEST OF THE CUMBERLAND PLATEAU, WITH TEMPS FORECAST
TO BE MAINLY IN THE MIDDLE 80S ALONG THE PLATEAU ITSELF.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
202 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL CROSS OVER THE GREAT LAKES
TODAY...AND PUSH A COLD FRONT ACROSS THE MID ATLANTIC. THIS FRONT
WILL TRIGGER NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EVENING...WITH A FEW STORMS POSSIBLY BECOMING STRONG TO SEVERE.
ONCE THE COLD FRONT DEPARTS LATER TONIGHT INTO SATURDAY...HIGH
PRESSURE WILL ARRIVE TO PROVIDE COOLER AND DRIER CONDITIONS FOR
THE REST OF THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1200 PM EDT FRIDAY...
THE SHOWERS OVER WEST VIRGINIA ARE STILL PRESENT BUT GRADUALLY
DECAYING. NEW DEVELOPMENT OF SHOWERS AND THUNDERSTORMS HAS BEEN
DELAYED A FEW HOURS TOWARD THE MID AFTERNOON AND EVENING...AS
INSTABILITY IS CURRENTLY STILL LACKING. THE THREAT FOR SEVERE
WEATHER TODAY CONTINUES TO DIMINISH DUE TO CLOUD COVER REMAINING
QUITE THICK OVER THE AREA...BUT SOME SUNSHINE IS PEEKING THROUGH
ALONG THE BLUE RIDGE. MINOR TWEAKS WERE MADE TO THE POPS AND
TEMPERATURES TO ACCOUNT FOR THE RECENT TRENDS ON RADAR AND
SATELLITE. ALSO...WINDS WERE BUMPED UPWARD DUE TO ROANOKE AND
DANVILLE BOTH OBSERVING A GUSTY SOUTHWEST WIND DEVELOPING...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON.
AS OF 1015 AM EDT FRIDAY...
DUE TO THE DEPARTING BAND OF SHOWERS AND THUNDERSTORMS FROM LAST
NIGHT...AND ANOTHER SMALL BAND OF SHOWERS CROSSING OVER SOUTHEAST
WEST VIRGINIA AT THIS MOMENT...THERE WILL BE LOTS OF CLOUD COVER
TO ERODE OVER THE AREA FOR ANY SIGNIFICANT RISK OF SEVERE WEATHER.
THE SMALL BAND OF SHOWERS OVER WEST VIRGINIA WILL GRADUALLY
DISSIPATE AS IT CROSSES THE BLUE RIDGE IN A FEW HOURS. RECOVERING
THE INSTABILITY WILL BE THE KEY FOR TODAY. LAPSE RATES IN THE 12Z
RNK SOUNDING ARE NOT IMPRESSIVE...BUT WITH ENOUGH DAYTIME HEATING
AND DYNAMICAL SUPPORT AS THE SURFACE COLD FRONT DRAWS
CLOSER...THERE SHOULD BE SUFFICIENT SUPPORT FOR THE GROWTH OF
NUMEROUS SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON. IF ANY OF
THESE STORMS BECOME STRONG TO SEVERE...DAMAGING WINDS AND HEAVY
RAIN WILL BE THE PRIMARY THREATS.
SINCE CLOUD COVER AND BANDS OF CONVECTION WILL BE ONGOING
THROUGHOUT THE DAY...THE TEMPERATURE FORECAST IS QUITE
PROBLEMATIC. AT THIS TIME...TEMPERATURES WERE BUMPED UPWARD FOR
HIGHS WEST OF THE BLUE RIDGE DUE TO SOME BREAKS IN THE CLOUDS.
OTHER AREAS WERE KEPT CLOSE TO THE PREVIOUS FORECAST AND MOS
GUIDANCE...WITH HIGHS IN THE MID TO UPPER 70S WEST OF THE BLUE
RIDGE...AND LOWER TO MID 80S IN THE PIEDMONT. WITH REGARDS TO
POPS...A SMALL AREA OF LIKELY CHANCES WERE UTILIZED TO ACCOUNT FOR
THE DECAYING BAND OF SHOWERS OVER WEST VIRGINIA THIS MORNING.
LIKELY POPS WEST OF THE BLUE RIDGE...AND CATEGORICAL POPS OVER THE
PIEDMONT WERE PLACED THIS AFTERNOON AND EVENING...AS THERE
SHOULD BE BANDED CONVECTION FORMING ALONG AND WEST OF THE BLUE
RIDGE...AND BECOMING MORE ORGANIZED AS IT HEADS EASTWARD.
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 200 PM EDT FRIDAY...
CEILINGS HAVE LIFTED BACK UP TO VFR THIS AFTERNOON...WITH THE
EXCEPTION OF MVFR CEILINGS STILL PERSISTING IN BLF. BROKEN LINES
OF SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER KENTUCKY AND
TENNESSEE...AND ARE EXPECTED TO CONTINUE MOVING EASTWARD ALONG THE
ADVANCING SURFACE FRONT. A FEW SHOWERS ARE ALSO POPPING UP OVER
WEST VIRGINIA AHEAD OF THE FRONT. THUS...THUNDERSTORMS WERE KEPT
IN ALL THE TAFS. THE TIMING OF THE CONVECTION HAS SLOWED DOWN
SEVERAL HOURS FROM THE PREVIOUS FORECAST. THE TIME RANGE BETWEEN
20Z AND 03Z NOW SEEMS MOST FAVORABLE FOR THUNDERSTORMS.
ONCE THE PRECIPITATION SUBSIDES TONIGHT...THE MOIST GROUND WILL
PROVIDE THE POTENTIAL FOR SOME MVFR FOG IN BLF AND BCB. LWB IS
MOST LIKELY TO DROP TO LIFR WHEN THE WINDS TURN CALM OVERNIGHT.
MEANWHILE...TOO MUCH LOW CLOUD COVER WILL IMPEDE FURTHER FOG
DEVELOPMENT TO THE EAST. BY SATURDAY MORNING...A DRIER AIR MASS
BEHIND THE FRONT WILL MOVE INTO THE AREA...AND PROMPT A RETURN TO
VFR CONDITIONS. HIGH PRESSURE WILL PROVIDE GOOD FLYING WEATHER
THROUGH THE REMAINDER OF THIS WEEKEND INTO EARLY NEXT WEEK.
ANOTHER DISTURBANCE WILL PROVIDE THE NEXT CHANCE OF ISOLATED
SHOWERS AND THUNDERSTORMS BY TUESDAY AND WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...JH/PW
SHORT TERM...KK
LONG TERM...WP
AVIATION...PW
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1201 PM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL CROSS OVER THE GREAT LAKES
TODAY...AND PUSH A COLD FRONT ACROSS THE MID ATLANTIC. THIS FRONT
WILL TRIGGER NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EVENING...WITH A FEW STORMS POSSIBLY BECOMING STRONG TO SEVERE.
ONCE THE COLD FRONT DEPARTS LATER TONIGHT INTO SATURDAY...HIGH
PRESSURE WILL ARRIVE TO PROVIDE COOLER AND DRIER CONDITIONS FOR
THE REST OF THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1200 PM EDT FRIDAY...
THE SHOWERS OVER WEST VIRGINIA ARE STILL PRESENT BUT GRADUALLY
DECAYING. NEW DEVELOPMENT OF SHOWERS AND THUNDERSTORMS HAS BEEN
DELAYED A FEW HOURS TOWARD THE MID AFTERNOON AND EVENING...AS
INSTABILITY IS CURRENTLY STILL LACKING. THE THREAT FOR SEVERE
WEATHER TODAY CONTINUES TO DIMINISH DUE TO CLOUD COVER REMAINING
QUITE THICK OVER THE AREA...BUT SOME SUNSHINE IS PEEKING THROUGH
ALONG THE BLUE RIDGE. MINOR TWEAKS WERE MADE TO THE POPS AND
TEMPERATURES TO ACCOUNT FOR THE RECENT TRENDS ON RADAR AND
SATELLITE. ALSO...WINDS WERE BUMPED UPWARD DUE TO ROANOKE AND
DANVILLE BOTH OBSERVING A GUSTY SOUTHWEST WIND DEVELOPING...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON.
AS OF 1015 AM EDT FRIDAY...
DUE TO THE DEPARTING BAND OF SHOWERS AND THUNDERSTORMS FROM LAST
NIGHT...AND ANOTHER SMALL BAND OF SHOWERS CROSSING OVER SOUTHEAST
WEST VIRGINIA AT THIS MOMENT...THERE WILL BE LOTS OF CLOUD COVER
TO ERODE OVER THE AREA FOR ANY SIGNIFICANT RISK OF SEVERE WEATHER.
THE SMALL BAND OF SHOWERS OVER WEST VIRGINIA WILL GRADUALLY
DISSIPATE AS IT CROSSES THE BLUE RIDGE IN A FEW HOURS. RECOVERING
THE INSTABILITY WILL BE THE KEY FOR TODAY. LAPSE RATES IN THE 12Z
RNK SOUNDING ARE NOT IMPRESSIVE...BUT WITH ENOUGH DAYTIME HEATING
AND DYNAMICAL SUPPORT AS THE SURFACE COLD FRONT DRAWS
CLOSER...THERE SHOULD BE SUFFICIENT SUPPORT FOR THE GROWTH OF
NUMEROUS SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON. IF ANY OF
THESE STORMS BECOME STRONG TO SEVERE...DAMAGING WINDS AND HEAVY
RAIN WILL BE THE PRIMARY THREATS.
SINCE CLOUD COVER AND BANDS OF CONVECTION WILL BE ONGOING
THROUGHOUT THE DAY...THE TEMPERATURE FORECAST IS QUITE
PROBLEMATIC. AT THIS TIME...TEMPERATURES WERE BUMPED UPWARD FOR
HIGHS WEST OF THE BLUE RIDGE DUE TO SOME BREAKS IN THE CLOUDS.
OTHER AREAS WERE KEPT CLOSE TO THE PREVIOUS FORECAST AND MOS
GUIDANCE...WITH HIGHS IN THE MID TO UPPER 70S WEST OF THE BLUE
RIDGE...AND LOWER TO MID 80S IN THE PIEDMONT. WITH REGARDS TO
POPS...A SMALL AREA OF LIKELY CHANCES WERE UTILIZED TO ACCOUNT FOR
THE DECAYING BAND OF SHOWERS OVER WEST VIRGINIA THIS MORNING.
LIKELY POPS WEST OF THE BLUE RIDGE...AND CATEGORICAL POPS OVER THE
PIEDMONT WERE PLACED THIS AFTERNOON AND EVENING...AS THERE
SHOULD BE BANDED CONVECTION FORMING ALONG AND WEST OF THE BLUE
RIDGE...AND BECOMING MORE ORGANIZED AS IT HEADS EASTWARD.
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM EDT FRIDAY...
INITIAL AREA OF LEFTOVER SHOWERS FROM EARLIER MCS SLOWLY FADING
ACROSS THE EAST AND SHOULD ONLY AFFECT KLYH DURING THE NEXT HOUR
OR TWO. OTRW LOOKING AT MAINLY MVFR CIGS THRU MID MORNING WITH
PERIODS OF IFR INCLUDING PATCHY FOG ESPCLY VALLEYS AND AROUND
KDAN/KLYH. NEXT BAND OF DEVELOPING CONVECTION NOW WEST OF THE
MOUNTAINS LOOKS TO ARRIVE ACROSS SE WVA AROUND MID MORNING BEFORE
WEAKENING. THUS WILL INCLUDE A VCSH AT KBLF/KLWB AND SHOW CIGS
LIFTING INTO VFR LEVELS ELSW BY LATE MORNING OR MIDDAY AS SW FLOW
STARTS TO MIX THINGS OUT. JUST HOW FAR EAST THIS BROKEN BAND OF
SHRA/TSRA MAKES IT IFFY GIVEN RATHER STABLE CONDITIONS SO WILL
HOLD OFF PUSHING COVERAGE EASTWARD FOR NOW.
HOWEVER EXPECT TO SEE MORE SHOWERS AND THUNDERSTORMS TAKE SHAPE
AHEAD OF THE UPSTREAM COLD FRONT LATE THIS MORNING INTO THE
AFTERNOON AS A DEEP UPPER LEVEL TROUGH APPROACHES THE AREA. WILL
BE LOOKING AT A FEW STRONG STORMS TO START THE AFTERNOON...AND
EXPECT THAT THESE STORMS WILL FORM INTO A LINE OR TWO JUST AHEAD
OF THE COLD FRONT AS IT ENTERS THE PIEDMONT REGION DURING EARLY
EVENING. THESE STORMS WILL BE CAPABLE OF PRODUCING STRONG WINDS
ALONG WITH PERIODIC MVFR/IFR THIS AFTERNOON. THEREFORE GIVEN
EXPECTED COVERAGE WILL INCLUDE CONVECTIVE MENTION AS PREVAILING
FROM WEST TO EAST STARTING THIS AFTERNOON. THUNDERSTORM ACTIVITY
IS EXPECTED TO END ACROSS THE AREA AS THE FRONT EXITS TO THE EAST
DURING LATE EVENING...AT WHICH POINT DRIER AIR ASSOCIATED WITH
HIGH PRESSURE WILL RESULT IN VFR CONDITIONS HEADING INTO THE EARLY
PART OF NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...JH/PW
SHORT TERM...KK
LONG TERM...WP
AVIATION...JH/KM/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
703 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL PASS INTO THE GREAT LAKES
TODAY...DRAGGING A COLD FRONT ACROSS THE REGION THIS EVENING.
THIS WILL RESULT IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING...WITH A FEW STORMS BECOMING STRONG TO
SEVERE. ONCE THE COLD FRONT MOVES EAST OF THE AREA LATE
TONIGHT...HIGH PRESSURE WILL BUILD IN...BRINGING COOLER AND DRIER
AIR IN FOR THE REMAINDER OF THE WEEKEND AND THE EARLY PART OF NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM EDT FRIDAY...
INITIAL AREA OF LEFTOVER SHOWERS FROM EARLIER MCS SLOWLY FADING
ACROSS THE EAST AND SHOULD ONLY AFFECT KLYH DURING THE NEXT HOUR
OR TWO. OTRW LOOKING AT MAINLY MVFR CIGS THRU MID MORNING WITH
PERIODS OF IFR INCLUDING PATCHY FOG ESPCLY VALLEYS AND AROUND
KDAN/KLYH. NEXT BAND OF DEVELOPING CONVECTION NOW WEST OF THE
MOUNTAINS LOOKS TO ARRIVE ACROSS SE WVA AROUND MID MORNING BEFORE
WEAKENING. THUS WILL INCLUDE A VCSH AT KBLF/KLWB AND SHOW CIGS
LIFTING INTO VFR LEVELS ELSW BY LATE MORNING OR MIDDAY AS SW FLOW
STARTS TO MIX THINGS OUT. JUST HOW FAR EAST THIS BROKEN BAND OF
SHRA/TSRA MAKES IT IFFY GIVEN RATHER STABLE CONDITIONS SO WILL
HOLD OFF PUSHING COVERAGE EASTWARD FOR NOW.
HOWEVER EXPECT TO SEE MORE SHOWERS AND THUNDERSTORMS TAKE SHAPE
AHEAD OF THE UPSTREAM COLD FRONT LATE THIS MORNING INTO THE
AFTERNOON AS A DEEP UPPER LEVEL TROUGH APPROACHES THE AREA. WILL
BE LOOKING AT A FEW STRONG STORMS TO START THE AFTERNOON...AND
EXPECT THAT THESE STORMS WILL FORM INTO A LINE OR TWO JUST AHEAD
OF THE COLD FRONT AS IT ENTERS THE PIEDMONT REGION DURING EARLY
EVENING. THESE STORMS WILL BE CAPABLE OF PRODUCING STRONG WINDS
ALONG WITH PERIODIC MVFR/IFR THIS AFTERNOON. THEREFORE GIVEN
EXPECTED COVERAGE WILL INCLUDE CONVECTIVE MENTION AS PREVAILING
FROM WEST TO EAST STARTING THIS AFTERNOON. THUNDERSTORM ACTIVITY
IS EXPECTED TO END ACROSS THE AREA AS THE FRONT EXITS TO THE EAST
DURING LATE EVENING...AT WHICH POINT DRIER AIR ASSOCIATED WITH
HIGH PRESSURE WILL RESULT IN VFR CONDITIONS HEADING INTO THE EARLY
PART OF NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...KK
LONG TERM...WP
AVIATION...JH/KM/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
345 AM EDT FRI AUG 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL PASS INTO THE GREAT LAKES
TODAY...DRAGGING A COLD FRONT ACROSS THE REGION THIS EVENING.
THIS WILL RESULT IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING...WITH A FEW STORMS BECOMING STRONG TO
SEVERE. ONCE THE COLD FRONT MOVES EAST OF THE AREA LATE
TONIGHT...HIGH PRESSURE WILL BUILD IN...BRINGING COOLER AND DRIER
AIR IN FOR THE REMAINDER OF THE WEEKEND AND THE EARLY PART OF NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM EDT FRIDAY...
MAIN CONCERN TODAY WITH THE DEGREE OF POSSIBLE RENEWED CONVECTION
LATER ON AS THE UPPER LOW TO THE NW PROPELS A STRONG COLD FRONT TO
ALONG THE WESTERN SLOPES THIS EVENING AND EAST OF THE BLUE RIDGE
OVERNIGHT. AGAIN ONE OF THE MAIN FACTORS IS WITH JUST HOW MUCH
DEEP INSTABILITY CAN BE GENERATED THIS AFTERNOON IN THE WAKE OF
THE CURRENT MVC THAT WILL EXIT THE CWA BY DAYBREAK. THIS FEATURE
AND ITS CONVECTION HAVE BASICALLY REMOVED ANY LINGERING CAPE FROM
THU EVENING AND WILL NEED A PERIOD OF STRONG HEATING TO REGENERATE
ENOUGH INSTABILITY FOR A MORE WIDESPREAD SEVERE THREAT. LATEST
FCST SOUNDINGS DO SHOW WIND FIELDS STRENGTHENING/BACKING ALOFT
AHEAD OF THE UPSTREAM TROF THRU THIS EVENING SUGGESTING POTENTIAL
FOR BANDS OF DEEPER CONVECTION THAT MAY EVENTUALLY LINE UP ESPCLY
OUT EAST BY THIS EVENING. HOWEVER LATEST MODELS REMAIN SPREAD
ACROSS THE BOARD WITH TIMING AND LOCATION ISSUES OF PRE- FRONTAL
LIFT PER SLOWNESS IN INITIALIZING WITH THE CURRENT REMNANT MCS
ATTM. APPEARS BEST SOLUTION IS TO LEAN TOWARD THE LATEST HRRR AND
GO WITH DEVELOPMENT OF MULTICELLULAR BANDS OVER THE MOUNTAINS BY
EARLY AFTERNOON PER UNIDIRECTIONAL FLOW AND THETA-E RIDGING...WITH
THIS COVERAGE OR ANOTHER LINE GRADUALLY ORGANIZING UPON HEADING
EAST INTO BETTER INSTABILITY OUT EAST THRU EARLY EVENING. THIS
AGAIN BASED ON AT LEAST SOME HEATING AS SUGGESTED BY THE LATEST
NAM WHICH BREAKS OPEN THE MID DECK LATER THIS MORNING AHEAD OF THE
BOUNDARY. THUS HAVE ADJUSTED POPS TO REFLECT A BREAK IN COVERAGE
PER WEAK SUBSIDENCE IN BEHIND THE PASSING VORT EARLY THIS
MORNING...INCREASING TO LIKELY/CAT POPS WEST EARLY/MID
AFTERNOON...THEN TRANSLATING EAST INTO EARLY THIS EVENING. THINK
COVERAGE MOVING ENOUGH TO PRECLUDE A FLASH FLOOD WATCH BUT
CERTAINLY A WIND THREAT GIVEN DECENT FCST DCAPES WHICH WILL COVER
IN THE HWO PER SWODY1 SLIGHT RISK. WILL STAY ON THE WARM SIDE OF
MOS TEMPS TODAY AS THINKING SOME INSOLATION BUT IF CLOUDS HOLD AND
CONVECTION FASTER THEN HIGH BUST POTENTIAL REMAINS.
EXPECT MAIN AXIS OF CONVECTION TO BE EAST OF THE MOUNTAINS THIS
EVENING AND MAY TAKE SOME TIME TO EXIT THE PIEDMONT AS ANOTHER WEAK
IMPULSE RIDES UP THE FRONT. THINK SEVERE POTENTIAL LIMITED BEHIND
THE INIT WAVE OF STORMS BUT LINGERING HEAVY RAIN THREAT COULD
PERSIST WHILE SHOWERS BECOME WIDELY SCATTERED OR END BEHIND THE
BOUNDARY OVER THE MOUNTAINS OVERNIGHT. THEREFORE DID DECREASE POPS
A BIT FASTER WEST THINKING CONVECTION WILL HELP TAKE DEEP MOISTURE
TO THE EAST LATE...BUT LIKELY STILL LOTS OF CLOUDS AS THE UPPER
FLOW REMAINS SW AND PARALLEL TO THE SFC FRONT. MAIN PUSH OF 85H
COOL ADVECTION WILL STILL BE WEST OF THE BLUE RIDGE LATE TONIGHT
SO KEEPING TEMPS WARMER OUT EAST AND NOT QUITE AS COOL MOUNTAINS
PER CLOUD COVER. OTRW RANGE OF LOWS FROM AROUND 60 FAR WEST TO
65-70 SE LOOKS BEST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT FRIDAY...
SHORTWAVE PIVOTS ACROSS THE CENTRAL APPALACHIANS SATURDAY AFTERNOON.
THIS WILL KEEP THE THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS
GOING IN THE EAST WITH COOL POOL ALOFT. 8H TEMPS COOL TO +14C...SO
WITH SOME CLOUD COVER FROM THE COLDER AIR ALOFT...EXPECT HIGHS
CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 70S IN THE
MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
DRIER AIR WILL FINALLY WORKS IN FROM THE NORTHWEST SATURDAY NIGHT
INTO SUNDAY WITH DEWPOINTS DROPPING INTO THE UPPER 40S/LOWER 50S IN
THE HIGHER ELEVATIONS WITH MID 50S VALLEYS. THE PIEDMONT COULD SEE
SOME 50S DEWPOINTS BUT HARD TO DISPLACE THE HUMID AIRMASS ACROSS THE
CAROLINAS AS THE FLOW ALOFT STAYS WSW. PLAYED LOW TEMPERATURES
SATURDAY NIGHT FROM THE LOWER 50S IN THE MOUNTAINS TO THE LOWER 60S
IN THE EAST.
ON SUNDAY...TEMPERATURES MODERATE WITH WSW FLOW AND MORE SUNSHINE.
HEIGHTS/8H TEMPERATURES INCREASE AGAIN...HIGHS SUNDAY RETURNING TO
AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. LEANED TOWARDS THE ECMWFBC FOR SUNDAY NIGHT LOW
TEMPERATURES WITH VALUES FROM THE MID 50S IN THE WEST TO THE MID 60S
IN THE EAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...
DRIER AIRMASS WILL BE DISPLACED DURING THIS PERIOD AS THE FRONT FROM
THE SHORT TERM PERIOD STALLS ACROSS THE CAROLINAS/TN VALLEY THEN
SHIFTS SLOWLY NORTH BY TUESDAY AS ANOTHER WAVE OF LOW PRESSURE
SHIFTS ACROSS IT FROM THE LOWER MISSOURI VALLEY INTO THE VA
TIDEWATER FROM MON-TUE. THIS FRONT WILL BE CLOSE ENOUGH THAT
SHOWER/TSRA CHANCES INCREASE AGAIN BY TUESDAY. ONCE THE
SHORTWAVE/ASSOCIATED SFC LOW PASS TUESDAY AFTERNOON...WEAK HIGH
PRESSURE WILL PUSH THE FRONT BACK SOUTH INTO THE GA/SC BY WEDNESDAY
AND THE AIRMASS DRIES OUT SOME...BUT THE UPPER TROUGH IS NOT AS DEEP
AS THIS WEEKENDS. OVERALL...THE TEMPS NEXT WEEK WILL AVERAGE
80S/LOWER 90S FOR HIGHS AND 60S FOR LOWS.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AS OF 105 AM EDT FRIDAY...
AXIS OF CONVECTION CONTINUES TO WORK NE JUST EAST OF THE BLUE
RIDGE ATTM AND EXPECT THIS COVERAGE TO AFFECT KDAN AND KLYH FOR A
FEW MORE HOURS WITH MVFR/IFR CONDITIONS. ELSW A FEW ADDED ISOLATED
SHRA POSSIBLE OVERNIGHT OTRW LOOKING AT MAINLY VFR BEFORE FOG
FORMATION SETS IN PENDING JUST HOW FAST THE MID DECK CANOPY ERODES
BY DAYBREAK. APPEARS THE NORMALLY FOGGY LOCATIONS SUCH AS KLWB
WILL SEE IFR/LIFR BY DAWN WITH MVFR/IFR POSSIBLE AT KBCB. EASTERN
AREAS MAY ALSO SEE SOME MVFR FOG DEVELOP IN THE WAKE OF THE
CURRENT SHRA/TSRA SO INCLUDING SOME LOWER VSBYS/CIGS EARLY FRIDAY.
SHOWER AND THUNDERSTORMS WILL INCREASE LATE FRIDAY MORNING AND
EARLY AFTERNOON AS A DEEP UPPER LEVEL TROUGH APPROACHES THE
AREA...WITH AN ASSOCIATED COLD FRONT ENTERING THE WESTERN PART OF
THE FORECAST AREA TOWARD THE END OF THE TAF PERIOD. WILL BE
LOOKING AT A FEW STRONG STORMS TO START THE AFTERNOON...AND EXPECT
THAT THESE STORMS WILL FORM INTO A LINE OR TWO JUST AHEAD OF THE
COLD FRONT AS IT ENTERS THE PIEDMONT REGION DURING EARLY EVENING.
THUNDERSTORM ACTIVITY IS EXPECTED TO END ACROSS THE AREA AS THE
FRONT EXITS TO THE EAST DURING LATE EVENING...AT WHICH POINT DRIER
AIR ASSOCIATED WITH HIGH PRESSURE WILL RESULT IN VFR CONDITIONS
HEADING INTO THE EARLY PART ON NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...KK
LONG TERM...WP
AVIATION...JH/KM/NF
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
638 PM CDT SAT AUG 11 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
STRETCHING ALONG THE MISSISSIPPI VALLEY TO HUDSON BAY WHILE LOW
PRESURE IS MOVING OVER THE DAKOTAS AND ALSO LAKE ERIE. WITH HIGH
PRESSURE OVER THE REGION...MOSTLY CLEAR SKIES HAVE PREVAILED ACROSS
THE FORECAST AREA THROUGH EARLY THIS AFTERNOON. MID AND HIGH CLOUDS
ARE ALREADY ADVANCING ACROSS THE NORTHERN MISSISSIPPI VALLEY AHEAD
OF THE NEXT STORM SYTEM OVER THE NORTHERN PLAINS. AS THE STORM
SYSTEM CONTINUES TO MOVE EAST...LIGHT PRECIP CHANCES TOMORROW ALONG
WITH CLOUDS AND TEMPS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...HIGH PRESSURE WILL REMAIN AT THE SURFACE ACROSS THE
WESTERN GREAT LAKES TONIGHT. HOWEVER...A SHORTWAVE TROUGH OVER THE
NORTHERN PLAINS WILL MOVE INTO THE NORTHERN MISSISSIPPI VALLEY
TONIGHT. A BLANKET OF MID AND HIGH CLOUDS WILL SPREAD ACROSS
CENTRAL AND EASTERN PORTIONS OF THE STATE LATE THIS EVENING THROUGH
THE OVERNIGHT. WITH DEWPOINTS MIXING OUT THIS AFTERNOON...POCKETS
OF GROUND FOG SHOULD ONLY BE NUISANCE LATE AND NOT EXPECTING
ANYTHING DENSE TO FORM. LOWS IN THE MID 40S NORTH TO MID 50S SOUTH.
SUNDAY...THE SHORTWAVE WILL PROCEED TO MOVE INTO THE STATE AND WILL
SEE A PRETTY THICK LAYER OF MID AND HIGH CLOUDS OVERHEAD. LOW LEVEL
MOISTURE WILL HANG TO THE WEST THOUGH CLOSER TO A SURFACE LOW OVER
IOWA. PROGGED SOUNDINGS REMAIN FAIRLY DRY BELOW 700MB...SO IF ANY
PRECIP WERE TO FALL OUT OF THE MID DECK...IT SHOULD ONLY BE
SPRINKLES. ADDED SPRINKLES OVER CENTRAL WISCONSIN FOR THE AFTERNOON.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. MODELS ARE IN
DECENT AGREEMENT WITH THE UPPER PATTERN THROUGH THE MIDDLE OF NEXT
WEEK THEN THE GFS AND ECMWF DIFFER IN HOW THEY HANDLE A
SIGNIFICANT UPPER TROUGH AS IT MOVES ACROSS THE GREAT LAKES. THE
ECMWF HAS A SHARPER UPPER TROUGH AND CLOSES OFF AN UPPER LOW OVER
LOWER MICHIGAN WHILE THE GFS TROUGH IS BROADER.
A WEAK UPPER TROUGH MOVING ACROSS THE AREA SUNDAY NIGHT AND MONDAY
SHOULD PRODUCE AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS DESPITE
THE SURFACE LOW BEING WELL SOUTH OF OUR AREA OVER ILLINOIS. HIGHS
MONDAY COULD BE COOLER THAN WHAT WE CURRENTLY HAVE IN THE FORECAST
IF SKIES ARE CLOUDY AND SHOWERS MORE ABUNDANT THAN NOW FORECAST.
THEN NORTHWEST UPPER FLOW SHOULD PROVIDE FOR DRY AND SEASONABLE
WEATHER FOR TUESDAY AND WEDNESDAY.
A SIGNIFICANT UPPER TROUGH WILL APPROACH WEDNESDAY NIGHT AND
THURSDAY AND PROVIDE SUFFICIENT UPPER SUPPORT FOR SHOWERS AND
THUNDERSTORMS. MODELS SUGGEST THERE WILL BE DECENT MID LEVEL WINDS
AND SHEAR BUT INSTABILITY IS MODEST. AFTER THAT GOES BY SOME
COOLER THAN NORMAL AIR WILL ARRIVE FOR THE END OF THE WEEK. GFS
FORECASTS SUBZERO 850 MB TEMPERATURES IN NORTHERN WISCONSIN FRIDAY
AFTERNOON.
&&
.AVIATION...HIGH PRESSURE WILL RESIDE OVER THE FCST AREA
TONIGHT...BUT HIGH CLOUDS WILL GRADUALLY OVERSPREAD THE REGION
FROM SW TO NE. THE CLOUD COVER WILL THICKEN DURING THE DAY ON
SUNDAY AS A SYSTEM APPROACHES FROM THE NORTHERN PLAINS. A FEW
LIGHT SHOWERS MAY WORK THEIR WAY INTO CENTRAL WI BY LATE
AFTERNOON. CONDITIONS WILL REMAIN VFR OVER MOST OF THE REGION
THROUGH THE TAF PERIOD...THOUGH PATCHY MVFR/IFR VSBYS IN FOG MAY
DEVELOP OVER NORTH CENTRAL WI LATE TONIGHT.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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
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
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 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 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
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 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
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 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 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 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 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 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 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 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 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.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...TL
AVIATION...CTC/TL
MARINE...CTC/TL
AREA FORECAST DISCUSSION
NWS TULSA OK
1230 PM CDT SUN AUG 12 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SCATTERED SHOWERS WILL CONTINUE WITHIN MID CLOUD DECK AHEAD OF
APPROACHING FRONTAL BOUNDARY. ISOLATED STORMS LATE AFTERNOON WILL
BE MENTIONED ACROSS OK SITES...WITH A LATE EVENING / NIGHT
MENTION FURTHER EAST AS FRONT SLOWS. CLEARING SKIES AND NORTHERLY
WINDS WILL FOLLOW FRONT.
&&
.PREV DISCUSSION... /ISSUED 1129 AM CDT SUN AUG 12 2012/
..UPDATE...
DISCUSSION...
COLD FRONT / SFC TROUGH CURRENTLY EXTENDS FROM NORTH CENTRAL OK
INTO SOUTHWEST OK WITH EXTENSIVE MID CLOUD PREVAILING AHEAD OF THE
BOUNDARY. SATELLITE SHOWS CLEARING RECENTLY UNDERWAY AHEAD OF THE
BOUNDARY...WHERE BOTH NAM AND RAP DATA HAVE TEMPS SOARING THIS
AFTERNOON. WHILE CURRENT TEMP TRENDS ARE BEHIND PACE...WILL
MAINTAIN FORECAST HIGHS AS A QUICK WARM UP THIS AFTERNOON IS
LIKELY. REGARDING AFTERNOON / EVENING CONVECTION...STRONGLY VEERED
FLOW WILL KEEP THE DEEPER MOISTURE CURRENTLY OVER EAST TEXAS
PUSHED TO OUR SE. THIS WILL DELAY...AND POSSIBLE HINDER...DEEP
CONVECTION THIS AFTERNOON. HOWEVER GIVEN THE APPROACHING WAVE
ALOFT AND EXPECTED SFC TEMPS...ADJUSTED FORECAST SOUNDINGS REMOVE
AFTERNOON INHIBITION WITHIN A MODERATELY SHEARED ENVIRONMENT. ANY
STORMS THAT DO FORM WILL BE HIGH BASED AND CAPABLE OF STRONG WINDS
AND HAIL. GIVEN LATEST LOCAL WRF RUNS ALONG WITH HRRR DATA WILL
KEEP THE POPS LOW GIVEN EXPECTATIONS OF IMITED STORM COVERAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 102 68 96 65 / 20 20 10 10
FSM 95 72 99 68 / 20 30 10 10
MLC 99 71 99 65 / 30 30 10 10
BVO 103 61 94 61 / 20 20 0 10
FYV 92 65 91 60 / 20 30 10 10
BYV 91 67 90 61 / 30 30 10 10
MKO 98 68 98 63 / 20 30 10 10
MIO 98 65 90 63 / 30 20 10 10
F10 100 69 98 65 / 30 20 10 10
HHW 98 73 100 68 / 30 40 20 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
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 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 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