Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/27/12
AREA FORECAST DISCUSSION
NWS DENVER CO
743 PM MDT SUN AUG 26 2012
.UPDATE...A FEW SHOWERS AND STORMS ARE LINGERING OVER ELBERT AND
LINCOLN COUNTIES. ACTIVITY CONTINUES TO FIRE OFF A BOUNDARY
DRIFTING WEST. AREAS WEST OF THIS BOUNDARY...ARE TOO DRY FOR
CONVECTION. DECREASED POPS ACROSS THE AREA FOR THE REST OF THE
EVENING WITH NO WEATHER AFTER MIDNIGHT. AIRMASS IS A LITTLE WARMER
THAN LAST NIGHT SO LOWS SHOULD BE A BIT HIGHER.
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH MONDAY. EASTERLY
WINDS WILL BECOME NORMAL SOUTHERLY DRAINAGE DIRECTION AROUND 06Z.
ON MONDAY...LIGHT AND VARIABLE WINDS DURING THE MORNING WILL
SHIFT SOUTHEASTERLY BY 18Z.
&&
.PREV DISCUSSION... /ISSUED 248 PM MDT SUN AUG 26 2012/
SHORT TERM...STORMS DEVELOPING ALONG A WIND CONVERGENCE BOUNDARY
SNAKING ACROSS SERN ELBERT...EXTREME NWRN LINCOLN AND SERN
WASHINGTON COUNTIES AS OF 20Z WILL BE THE AREA TO WATCH FOR THE
NEXT FEW HOURS. DEWPOINTS IN THE MID-UPPER 50S EAST OF THIS
BOUNDARY AND IN THE 30S WEST OF THERE. GOOD SOUTHERLY INFLOW
GENERATING A FEW WEAK VORTICITY COUPLETS INDICATED ON RADAR ALONG
THIS CONVERGENCE LINE. LATEST RUC IS INDICATING SFC BASED CAPES IN
THE 1000-1400 J/KG RANGE IN THE MOIST AIR. HOWEVER STRONG MID-
LEVEL STABLE LAYER MAY HINDER THE GROWTH OF STRONG STORMS. FOR
NOW WILL UP POPS ALONG THIS CONVERGENCE BOUNDARY AND EXTEND 20-30
PCT POPS NORTHWARD ACROSS PHILLIPS AND SEDGWICK COUNTIES THRU EARLY
THIS EVENING. MODELS SHOW THIS BOUNDARY AND THE MOIST AIR SHIFTING
EAST OUT OF THE STATE BETWEEN 03-06Z THIS EVENING. ELSEWHERE...
CONVECTION HAS STRUGGLED TO GET GOING IN THE HIGH COUNTRY...NO
DOUBT BECAUSE OF THE STRONG WARMING AND STABILITY AT MID-LEVELS.
SHOULD ANY STORMS MANAGE TO DEVELOP...WOULDN/T EXPECT THEM TO LAST
LONG. LOOKING FOR LOW TEMPERATURES TONIGHT TO BE A FEW DEGREES
WARMER THAN THOSE LAST NIGHT.
ON MONDAY...A 594 DECAMETER UPPER RIDGE POSITIONS SQUARELY OVER
COLORADO. MID-LEVEL MOISTURE OF SUBTROPICAL ORIGIN WILL CONTINUE
TO RIDE NORTH UP THE WEST SIDE OF THE RIDGE AND OVER WESTERN
COLORADO DURING THE DAY. BELIEVE WE/LL SEE A BIT MORE STORM
ACTIVITY IN THE HIGH COUNTRY TOMORROW. EAST OF THE MTNS...STORMS
WILL STRUGGLE TO DEVELOP...ALTHOUGH COULD SEE A FEW HIGH BASED
STORMS DRIFTING OFF THE FRONT RANGE AND OVER THE NEARBY PLAINS
LATE IN THE DAY. FOR NOW WILL KEEP POPS ON THE VERY LOW SIDE IN
THE I-25 URBAN CORRIDOR BUT WILL GO WITH 20-30 PCT POPS IN THE
HIGH COUNTRY. FARTHER OUT ON THE PLAINS WILL KEEP THINGS DRY.
LOOKING FOR ANOTHER DAY OF 90 DEG TEMPERATURES AT LOWER
ELEVATIONS.
LONG TERM...THE RIDGE OF HIGH PRESSURE WILL REMAIN ANCHORED OVER
COLORADO THROUGH WEDNESDAY. HOTTER TEMPERATURES AND LIMITED
MOISTURE WILL OCCUR THROUGH FIRST HALF OF THE WEEK. THE BEST CHC
OF THUNDERSTORMS WILL BE OVER THE MOUNTAINS EACH AFTERNOON AND
EVENING. THE WINDS ALOFT WILL REMAIN LIGHT. LATE WEDNESDAY INTO
THURSDAY THE RIDGE WILL FLATTEN AND THE FLOW ALOFT BECOME
SOUTHWESTERLY AS AN UPPER TROUGH MOVES ACROSS THE NRN ROCKIES. BY
THURSDAY THE RIDGE WILL HAVE SHIFTED INTO THE CENTRAL
PLAINS/MIDWEST REGION. THERE WILL BE A MODEST INCREASE IN
SUBTROPICAL MOISTURE AS WELL...WITH A LITTLE BETTER CHANCE OF
PRECIPITATION IN THE MOUNTAINS AND A SLIGHT CHANCE SPREADING INTO
THE NORTHEAST PLAINS FRIDAY THROUGH SUNDAY. IT WILL NOT BE AS HOT
AS A COUPLE OF WEAK FRONTAL BOUNDARIES SLIP INTO THE CWFA FROM
THE NORTH...ONE LATE WEDNESDAY/THURSDAY AND ANOTHER SATURDAY.
AVIATION...VFR CONDITIONS TO CONTINUE THROUGH MONDAY UNDER A
RIDGE OF HIGH PRESSURE. COULD SEE A FEW HIGH BASED MOSTLY DRY AND
GUSTY STORMS MOVING OFF THE FOOTHILLS LATE MONDAY AFTERNOON.
OTHERWISE LIGHT EAST-SOUTHEASTERLY WINDS WILL BECOME SOUTHERLY OR
DRAINAGE OVERNIGHT. A SIMILAR WIND PATTERN IS EXPECTED ON MONDAY.
HYDROLOGY...NO HEAVY RAIN OR FLASH FLOOD ISSUES ANTICIPATED
DURING THE NEXT 24 HOURS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....COOPER
UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1055 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED NEAR THE CANADIAN MARITIMES WILL TRACK
EASTWARD TODAY THEN BECOMES ELONGATED BACK TOWARDS THE NEW ENGLAND
COAST TONIGHT AND SUNDAY. MEANWHILE...AN UPPER LEVEL LOW OVER THE
MID ATLANTIC WILL MOVE SLOWLY NORTHEAST TOWARD THE AREA. A COLD
FRONT IS FORECAST TO MOVE SOUTHEAST CROSS THE AREA TUESDAY
FOLLOWED BY HIGH PRESSURE WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MINOR UPDATES TO DEW POINT THIS MORNING. OTHERWISE...REMAINDER OF
FORECAST IS ON TRACK.
A WEAK UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MID ATLANTIC
STATES WILL CONTINUE TO SEND ABUNDANT MID AND HIGH LEVEL CLOUDS
INTO THE AREA TODAY. SOME AREAS MAY EXPERIENCE FILTERED SUNSHINE
THIS MORNING BUT IT WILL EVENTUALLY GIVE WAY TO THICKER CLOUDS
WITH MOSTLY CLOUDY SKIES DEVELOPING BY AFTERNOON.
VORT ENERGY FROM THIS LOW WILL ADVANCE TOWARDS THE AREA TODAY. 12Z
SOUNDING SHOWING THAT AN ONSHORE FLOW HAS RESULTED IN A INCREASE
OF LOW LEVEL MOISTURE AND THERE COULD BE A FEW SHOWERS AROUND
LATER THIS AFTERNOON. LATEST HRRR DOES INDICATE SOME LIGHT ECHOES
EARLY THIS AFTERNOON ACROSS WESTERN PORTIONS OF THE CWA. HAVE
MAINTAINED SCHC POPS AS A RESULT. SUBSIDENCE FROM DEPARTING HIGH
PRES MAY BE ENOUGH TO KEEP EXTREME EASTERN AREAS DRY TODAY SO NO
POPS.
MOS GUIDANCE WAS CLOSE ON HIGH TEMPS TODAY AND USED A BLEND.
THERE IS A MODERATE RISK OF RIP CURRENTS AT ATLANTIC OCEAN BEACHES
TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
UPPER LEVEL RIDGING OVER THE ATLANTIC BUILDS BACK TOWARDS THE
EAST COAST TONIGHT WITH THE UPPER LEVEL LOW WEAKENING. HAVE GONE
WITH A DRY FORECAST UNTIL LATE TONIGHT THROUGH SUNDAY WITH ONLY SCHC
POPS RETURNING ACROSS WESTERN AREAS AS MAJORITY OF MOISTURE AND
LIFT ASSOCIATED WITH THE MID ATLANTIC SYSTEM ARE FORECAST TO REMAIN TO
OUR SW.
ONSHORE FLOW CONTINUES THROUGH SUN WITH TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL LOW IN MID-ATLANTIC FINALLY GETS ABSORBED INTO MEAN
FLOW SUN NIGHT AND MOVES ACROSS MON MORNING. THIS WILL BE THE BEST
CHC OF THE LOCAL AREA SEEING ANY PRECIP FROM THIS SYSTEM. ELEVATED
INSTABILITY ALSO DEVELOPS SO TSTMS WILL BE POSSIBLE. FCST MODELS
SHOW A STRONGER UPPER LVL TROUGH APPROACHING WITH A HIGHER
PROBABILITY OF SCT SHOWERS AND TSTMS...MAINLY FROM MONDAY AFTN
THROUGH NOON TUESDAY. AS ALWAYS...TIMING THIS FRONTAL PASSAGE WILL
BE A CHALLENGE. AS THIS FRONT MOVES INTO A WARM...MOIST UNSTABLE
MARITIME TROPICAL AIR MASS...A FEW STORMS COULD PRODUCE HVY RAIN
AND STRONG GUSTY WINDS.
TUE NIGHT THROUGH FRI...FCST MODELS SHOW HIGH PRES MVG SE TOWARD
THE AREA COURTESY OF A WELL DEFINED HIGH AMPLITUDE UPSTREAM RIDGE
ACROSS THE WESTERN U.S. THIS WILL REPLACE THE MARITIME TROPICAL AIR
MASS WITH A FRESH AND DRIER CONTINENTAL POLAR AIR MASS.
REGARDING THE FORECAST FOR ISAAC...PLEASE REFER TO THE LATEST
NATIONAL HURRICANE CENTER FORECASTS. AT THIS TIME...IT APPEARS THAT
THE REMNANTS FROM ISAAC MAY PASS SOUTH OF THE LOCAL AREA NEXT
THURSDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN NEAR THE CANADIAN MARITIMES THROUGH THE
DAY TODAY.
AN EAST TO SOUTHEAST FLOW ACROSS THE AREA WILL KEEP SOME STRATUS
AT THE COASTAL TERMINALS THROUGH MUCH OF THE DAY...HOWEVER...DO
NOT EXPECT MVFR CEILINGS.
VFR. WEAK LOW PRESSURE ALONG THE MID ATLANTIC COAST MAY BRING SOME
MID CLOUDS TO THE TERMINALS THIS AFTERNOON.
AN ISOLATED SHOWER THIS AFTERNOON WILL BE POSSIBLE...BUT DO NOT
EXPECT COVERAGE TO BE HIGH ENOUGH TO INCLUDE IN THE FORECAST AT
THIS TIME.
FOR TONIGHT...WINDS LIGHTEN AS THEY TURN BACK TOWARD THE
EAST/NORTHEAST. NOT TOO CONFIDENT IN FOG DEVELOPMENT TONIGHT...BUT
THIS WILL NEED TO BE WATCHED AS WELL.
OUTLOOK FOR 12Z SUNDAY THROUGH WED...
.SUNDAY...MAINLY VFR. ISOLATED SHOWERS/TSTMS POSSIBLE WITH BRIEF
MVFR OR LOWER CONDS.
.MON-TUE...MVFR OR LOWER CONDS POSSIBLE...ESPECIALLY IN ANY
SHOWERS/TSTMS THAT DEVELOP AS A COLD FRONT APPROACHES.
BEST CHANCES FOR THESE LOWER CONDITIONS TUE.
.WED...VFR.
&&
.MARINE...
AS HIGH PRESSURE MOVES AROUND THE CANADIAN MARITIMES AND OFF THE NEW
ENGLAND COAST THROUGH THE REMAINDER OF THE WEEKEND...EXPECT A
PERSISTENT EASTERLY WIND FLOW ACROSS THE LOCAL WATERS. THESE
EASTERLY WINDS WILL SHIFT AROUND THE SOUTH AND SOUTHWEST LATER MONDAY
AND MONDAY NIGHT. THIS WIND SHIFT WILL OCCUR AS THE CENTER OF THE
HIGH DRIFTS EAST AND A COLD FRONT APPROACHES FROM THE NORTHWEST.
THE COLD FRONT WILL PASS ACROSS THE WATERS TUESDAY...FOLLOWED BY
HIGH PRESSURE THROUGH MID WEEK.
SEAS SLOWLY BUILD THIS WEEKEND IN RESPONSE TO THE EASTERLY FLOW...BUT
DO EXPECT WINDS AND SEAS TO REMAIN JUST UNDER SCA CRITERIA.
SEAS SHOULD THEN SETTLE AND REMAIN AROUND 3 OR 4 FT THROUGH THE
EARLY PART OF THE WEEK ACROSS THE OCEAN WATERS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE WEEKEND.
MON THROUGH TUE...SCT HEAVIER SHOWERS AND TSTMS COULD PRODUCE 1/2 TO
1 INCH OF RAIN IN ADVANCE OF AN APPROACHING COLD FRONT. ISOLATED
URBAN FLOODING IS POSSIBLE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...BC
SHORT TERM...
LONG TERM...
AVIATION...MET
MARINE...
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1008 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED NEAR THE CANADIAN MARITIMES WILL TRACK
EASTWARD TODAY THEN BECOMES ELONGATED BACK TOWARDS THE NEW ENGLAND
COAST TONIGHT AND SUNDAY. MEANWHILE...AN UPPER LEVEL LOW OVER THE
MID ATLANTIC WILL MOVE SLOWLY NORTHEAST TOWARD THE AREA. A COLD
FRONT IS FORECAST TO MOVE SOUTHEAST CROSS THE AREA TUESDAY
FOLLOWED BY HIGH PRESSURE WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MINOR UPDATES TO DEW POINT THIS MORNING. OTHERWISE...REMAINDER OF
FORECAST IS ON TRACK.
A WEAK UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MID ATLANTIC
STATES WILL CONTINUE TO SEND ABUNDANT MID AND HIGH LEVEL CLOUDS
INTO THE AREA TODAY. SOME AREAS MAY EXPERIENCE FILTERED SUNSHINE
THIS MORNING BUT IT WILL EVENTUALLY GIVE WAY TO THICKER CLOUDS
WITH MOSTLY CLOUDY SKIES DEVELOPING BY AFTERNOON.
VORT ENERGY FROM THIS LOW WILL ADVANCE TOWARDS THE AREA TODAY. 12Z
SOUNDING SHOWING THAT AN ONSHORE FLOW HAS RESULTED IN A INCREASE
OF LOW LEVEL MOISTURE AND THERE COULD BE A FEW SHOWERS AROUND
LATER THIS AFTERNOON. LATEST HRRR DOES INDICATE SOME LIGHT ECHOES
EARLY THIS AFTERNOON ACROSS WESTERN PORTIONS OF THE CWA. HAVE
MAINTAINED SCHC POPS AS A RESULT. SUBSIDENCE FROM DEPARTING HIGH
PRES MAY BE ENOUGH TO KEEP EXTREME EASTERN AREAS DRY TODAY SO NO
POPS.
MOS GUIDANCE WAS CLOSE ON HIGH TEMPS TODAY AND USED A BLEND.
THERE IS A MODERATE RISK OF RIP CURRENTS AT ATLANTIC OCEAN BEACHES
TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
UPPER LEVEL RIDGING OVER THE ATLANTIC BUILDS BACK TOWARDS THE
EAST COAST TONIGHT WITH THE UPPER LEVEL LOW WEAKENING. HAVE GONE
WITH A DRY FORECAST UNTIL LATE TONIGHT THROUGH SUNDAY WITH ONLY SCHC
POPS RETURNING ACROSS WESTERN AREAS AS MAJORITY OF MOISTURE AND
LIFT ASSOCIATED WITH THE MID ATLANTIC SYSTEM ARE FORECAST TO REMAIN TO
OUR SW.
ONSHORE FLOW CONTINUES THROUGH SUN WITH TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL LOW IN MID-ATLANTIC FINALLY GETS ABSORBED INTO MEAN
FLOW SUN NIGHT AND MOVES ACROSS MON MORNING. THIS WILL BE THE BEST
CHC OF THE LOCAL AREA SEEING ANY PRECIP FROM THIS SYSTEM. ELEVATED
INSTABILITY ALSO DEVELOPS SO TSTMS WILL BE POSSIBLE. FCST MODELS
SHOW A STRONGER UPPER LVL TROUGH APPROACHING WITH A HIGHER
PROBABILITY OF SCT SHOWERS AND TSTMS...MAINLY FROM MONDAY AFTN
THROUGH NOON TUESDAY. AS ALWAYS...TIMING THIS FRONTAL PASSAGE WILL
BE A CHALLENGE. AS THIS FRONT MOVES INTO A WARM...MOIST UNSTABLE
MARITIME TROPICAL AIR MASS...A FEW STORMS COULD PRODUCE HVY RAIN
AND STRONG GUSTY WINDS.
TUE NIGHT THROUGH FRI...FCST MODELS SHOW HIGH PRES MVG SE TOWARD
THE AREA COURTESY OF A WELL DEFINED HIGH AMPLITUDE UPSTREAM RIDGE
ACROSS THE WESTERN U.S. THIS WILL REPLACE THE MARITIME TROPICAL AIR
MASS WITH A FRESH AND DRIER CONTINENTAL POLAR AIR MASS.
REGARDING THE FORECAST FOR ISAAC...PLEASE REFER TO THE LATEST
NATIONAL HURRICANE CENTER FORECASTS. AT THIS TIME...IT APPEARS THAT
THE REMNANTS FROM ISAAC MAY PASS SOUTH OF THE LOCAL AREA NEXT
THURSDAY.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN NEAR THE CANADIAN MARITIMES THROUGH THE
DAY TODAY.
AREAS OF MVFR OR IFR CONDITIONS IN FOG AND STRATUS EARLY THIS
MORNING WILL IMPROVE QUICKLY AS THE MORNING PROGRESSES.
THEREAFTER...VFR WITH MID AND HIGH CLOUDS EXPECTED TODAY. WINDS
REMAIN LIGHT E/NE EARLY THIS MORNING...THEN INCREASE FROM THE
EAST/SOUTHEAST CLOSE TO 10 KTS BY AFTERNOON. CANNOT RULE OUT AN
ISOLATED SHOWER THIS AFTERNOON...BUT DO NOT EXPECT COVERAGE TO BE
HIGH ENOUGH TO INCLUDE IN THE FORECAST AT THIS TIME. WILL NEED TO
MONITOR SHOWERS TO THE SOUTH.
FOR TONIGHT...WINDS LIGHTEN AS THEY TURN BACK TOWARD THE
EAST/NORTHEAST. NOT TOO CONFIDENT IN FOG DEVELOPMENT TONIGHT...BUT
THIS WILL NEED TO BE WATCHED AS WELL.
OUTLOOK FOR 12Z SUNDAY THROUGH WED...
.SUNDAY...MAINLY VFR. ISOLATED SHOWERS/TSTMS POSSIBLE WITH BRIEF
MVFR OR LOWER CONDS.
.MON-TUE...MVFR OR LOWER CONDS POSSIBLE...ESPECIALLY IN ANY
SHOWERS/TSTMS THAT DEVELOP AS A COLD FRONT APPROACHES.
BEST CHANCES FOR THESE LOWER CONDITIONS TUE.
.WED...VFR.
&&
.MARINE...
AS HIGH PRESSURE MOVES AROUND THE CANADIAN MARITIMES AND OFF THE NEW
ENGLAND COAST THROUGH THE REMAINDER OF THE WEEKEND...EXPECT A
PERSISTENT EASTERLY WIND FLOW ACROSS THE LOCAL WATERS. THESE
EASTERLY WINDS WILL SHIFT AROUND THE SOUTH AND SOUTHWEST LATER MONDAY
AND MONDAY NIGHT. THIS WIND SHIFT WILL OCCUR AS THE CENTER OF THE
HIGH DRIFTS EAST AND A COLD FRONT APPROACHES FROM THE NORTHWEST.
THE COLD FRONT WILL PASS ACROSS THE WATERS TUESDAY...FOLLOWED BY
HIGH PRESSURE THROUGH MID WEEK.
SEAS SLOWLY BUILD THIS WEEKEND IN RESPONSE TO THE EASTERLY FLOW...BUT
DO EXPECT WINDS AND SEAS TO REMAIN JUST UNDER SCA CRITERIA.
SEAS SHOULD THEN SETTLE AND REMAIN AROUND 3 OR 4 FT THROUGH THE
EARLY PART OF THE WEEK ACROSS THE OCEAN WATERS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE WEEKEND.
MON THROUGH TUE...SCT HEAVIER SHOWERS AND TSTMS COULD PRODUCE 1/2 TO
1 INCH OF RAIN IN ADVANCE OF AN APPROACHING COLD FRONT. ISOLATED
URBAN FLOODING IS POSSIBLE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...BC
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
730 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED NEAR THE CANADIAN MARITIMES WILL TRACK
EASTWARD TODAY THEN BECOMES ELONGATED BACK TOWARDS THE NEW ENGLAND
COAST TONIGHT AND SUNDAY. MEANWHILE...AN UPPER LEVEL LOW OVER THE
MID ATLANTIC WILL MOVE SLOWLY NORTHEAST TOWARD THE AREA. A COLD
FRONT IS FORECAST TO MOVE SOUTHEAST CROSS THE AREA TUESDAY
FOLLOWED BY HIGH PRESSURE WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MINOR UPDATES TO T/TD/SKY AND WINDS THIS MORNING. REMAINDER OF
FORECAST IS ON TRACK.
A WEAK UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MID ATLANTIC
STATES WILL CONTINUE TO SEND ABUNDANT MID AND HIGH LEVEL CLOUDS
INTO THE AREA TODAY. SOME AREAS MAY EXPERIENCE FILTERED SUNSHINE
THIS MORNING BUT IT WILL EVENTUALLY GIVE WAY TO THICKER CLOUDS
WITH MOSTLY CLOUDY SKIES DEVELOPING BY AFTERNOON.
VORT ENERGY FROM THIS LOW WILL ADVANCE TOWARDS THE AREA TODAY. 00Z
OKX SOUNDING INDICATES A DRY PROFILE HOWEVER...AN ONSHORE FLOW
WILL BE INCREASING LOW LEVEL MOISTURE AND THERE COULD BE A FEW
SHOWERS AROUND. LATEST HRRR DOES INDICATE SOME LIGHT ECHOES EARLY
THIS AFTERNOON ACROSS WESTERN PORTIONS OF THE CWA. HAVE MAINTAINED
SCHC POPS AS A RESULT. HAVE REMOVED MENTION OF THUNDER WITH LITTLE
INSTABILITY FORECAST AND EQL LEVEL FORECAST TO BE AROUND -10C.
SUBSIDENCE FROM DEPARTING HIGH PRES MAY BE ENOUGH TO KEEP EXTREME
EASTERN AREAS DRY TODAY SO NO POPS.
MOS GUIDANCE WAS CLOSE ON HIGH TEMPS TODAY AND USED A BLEND.
THERE IS A MODERATE RISK OF RIP CURRENTS AT ATLANTIC OCEAN BEACHES
TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
UPPER LEVEL RIDGING OVER THE ATLANTIC BUILDS BACK TOWARDS THE
EAST COAST TONIGHT WITH THE UPPER LEVEL LOW WEAKENING. HAVE GONE
WITH A DRY FORECAST UNTIL LATE TONIGHT THROUGH SUNDAY WITH ONLY SCHC
POPS RETURNING ACROSS WESTERN AREAS AS MAJORITY OF MOISTURE AND
LIFT ASSOCIATED WITH THE MID ATLANTIC SYSTEM ARE FORECAST TO REMAIN TO
OUR SW.
ONSHORE FLOW CONTINUES THROUGH SUN WITH TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL LOW IN MID-ATLANTIC FINALLY GETS ABSORBED INTO MEAN
FLOW SUN NIGHT AND MOVES ACROSS MON MORNING. THIS WILL BE THE BEST
CHC OF THE LOCAL AREA SEEING ANY PRECIP FROM THIS SYSTEM. ELEVATED
INSTABILITY ALSO DEVELOPS SO TSTMS WILL BE POSSIBLE. FCST MODELS
SHOW A STRONGER UPPER LVL TROUGH APPROACHING WITH A HIGHER
PROBABILITY OF SCT SHOWERS AND TSTMS...MAINLY FROM MONDAY AFTN
THROUGH NOON TUESDAY. AS ALWAYS...TIMING THIS FRONTAL PASSAGE WILL
BE A CHALLENGE. AS THIS FRONT MOVES INTO A WARM...MOIST UNSTABLE
MARITIME TROPICAL AIR MASS...A FEW STORMS COULD PRODUCE HVY RAIN
AND STRONG GUSTY WINDS.
TUE NIGHT THROUGH FRI...FCST MODELS SHOW HIGH PRES MVG SE TOWARD
THE AREA COURTESY OF A WELL DEFINED HIGH AMPLITUDE UPSTREAM RIDGE
ACROSS THE WESTERN U.S. THIS WILL REPLACE THE MARITIME TROPICAL AIR
MASS WITH A FRESH AND DRIER CONTINENTAL POLAR AIR MASS.
REGARDING THE FORECAST FOR ISAAC...PLEASE REFER TO THE LATEST
NATIONAL HURRICANE CENTER FORECASTS. AT THIS TIME...IT APPEARS THAT
THE REMNANTS FROM ISAAC MAY PASS SOUTH OF THE LOCAL AREA NEXT
THURSDAY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN NEAR THE CANADIAN MARITIMES THROUGH THE
DAY TODAY.
AREAS OF MVFR OR IFR CONDITIONS IN FOG AND STRATUS EARLY THIS
MORNING WILL IMPROVE QUICKLY AS THE MORNING PROGRESSES.
THEREAFTER...VFR WITH MID AND HIGH CLOUDS EXPECTED TODAY. WINDS
REMAIN LIGHT E/NE EARLY THIS MORNING...THEN INCREASE FROM THE
EAST/SOUTHEAST CLOSE TO 10 KTS BY AFTERNOON. CANNOT RULE OUT AN
ISOLATED SHOWER THIS AFTERNOON...BUT DO NOT EXPECT COVERAGE TO BE
HIGH ENOUGH TO INCLUDE IN THE FORECAST AT THIS TIME. WILL NEED TO
MONITOR SHOWERS TO THE SOUTH.
FOR TONIGHT...WINDS LIGHTEN AS THEY TURN BACK TOWARD THE
EAST/NORTHEAST. NOT TOO CONFIDENT IN FOG DEVELOPMENT TONIGHT...BUT
THIS WILL NEED TO BE WATCHED AS WELL.
OUTLOOK FOR 12Z SUNDAY THROUGH WED...
.SUNDAY...MAINLY VFR. ISOLATED SHOWERS/TSTMS POSSIBLE WITH BRIEF
MVFR OR LOWER CONDS.
.MON-TUE...MVFR OR LOWER CONDS POSSIBLE...ESPECIALLY IN ANY
SHOWERS/TSTMS THAT DEVELOP AS A COLD FRONT APPROACHES.
BEST CHANCES FOR THESE LOWER CONDITIONS TUE.
.WED...VFR.
&&
.MARINE...
AS HIGH PRESSURE MOVES AROUND THE CANADIAN MARITIMES AND OFF THE NEW
ENGLAND COAST THROUGH THE REMAINDER OF THE WEEKEND...EXPECT A
PERSISTENT EASTERLY WIND FLOW ACROSS THE LOCAL WATERS. THESE
EASTERLY WINDS WILL SHIFT AROUND THE SOUTH AND SOUTHWEST LATER MONDAY
AND MONDAY NIGHT. THIS WIND SHIFT WILL OCCUR AS THE CENTER OF THE
HIGH DRIFTS EAST AND A COLD FRONT APPROACHES FROM THE NORTHWEST.
THE COLD FRONT WILL PASS ACROSS THE WATERS TUESDAY...FOLLOWED BY
HIGH PRESSURE THROUGH MID WEEK.
SEAS SLOWLY BUILD THIS WEEKEND IN RESPONSE TO THE EASTERLY FLOW...BUT
DO EXPECT WINDS AND SEAS TO REMAIN JUST UNDER SCA CRITERIA.
SEAS SHOULD THEN SETTLE AND REMAIN AROUND 3 OR 4 FT THROUGH THE
EARLY PART OF THE WEEK ACROSS THE OCEAN WATERS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE WEEKEND.
MON THROUGH TUE...SCT HEAVIER SHOWERS AND TSTMS COULD PRODUCE 1/2 TO
1 INCH OF RAIN IN ADVANCE OF AN APPROACHING COLD FRONT. ISOLATED
URBAN FLOODING IS POSSIBLE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
643 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED NEAR THE CANADIAN MARITIMES WILL TRACK
EASTWARD TODAY THEN BECOMES ELONGATED BACK TOWARDS THE NEW ENGLAND
COAST TONIGHT AND SUNDAY. MEANWHILE...AN UPPER LEVEL LOW OVER THE
MID ATLANTIC WILL MOVE SLOWLY NORTHEAST TOWARD THE AREA. A COLD
FRONT IS FORECAST TO MOVE SOUTHEAST CROSS THE AREA TUESDAY
FOLLOWED BY HIGH PRESSURE WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MINOR UPDATES TO T/TD/SKY AND WINDS THIS MORNING. REMAINDER OF
FORECAST IS ON TRACK.
A WEAK UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MID ATLANTIC
STATES WILL CONTINUE TO SEND ABUNDANT MID AND HIGH LEVEL CLOUDS
INTO THE AREA TODAY. SOME AREAS MAY EXPERIENCE FILTERED SUNSHINE
THIS MORNING BUT IT WILL EVENTUALLY GIVE WAY TO THICKER CLOUDS
WITH MOSTLY CLOUDY SKIES DEVELOPING BY AFTERNOON.
VORT ENERGY FROM THIS LOW WILL ADVANCE TOWARDS THE AREA TODAY. 00Z
OKX SOUNDING INDICATES A DRY PROFILE HOWEVER...AN ONSHORE FLOW
WILL BE INCREASING LOW LEVEL MOISTURE AND THERE COULD BE A FEW
SHOWERS AROUND. LATEST HRRR DOES INDICATE SOME LIGHT ECHOES EARLY
THIS AFTERNOON ACROSS WESTERN PORTIONS OF THE CWA. HAVE MAINTAINED
SCHC POPS AS A RESULT. HAVE REMOVED MENTION OF THUNDER WITH LITTLE
INSTABILITY FORECAST AND EQL LEVEL FORECAST TO BE AROUND -10C.
SUBSIDENCE FROM DEPARTING HIGH PRES MAY BE ENOUGH TO KEEP EXTREME
EASTERN AREAS DRY TODAY SO NO POPS.
MOS GUIDANCE WAS CLOSE ON HIGH TEMPS TODAY AND USED A BLEND.
THERE IS A MODERATE RISK OF RIP CURRENTS AT ATLANTIC OCEAN BEACHES
TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
UPPER LEVEL RIDGING OVER THE ATLANTIC BUILDS BACK TOWARDS THE
EAST COAST TONIGHT WITH THE UPPER LEVEL LOW WEAKENING. HAVE GONE
WITH A DRY FORECAST UNTIL LATE TONIGHT THROUGH SUNDAY WITH ONLY SCHC
POPS RETURNING ACROSS WESTERN AREAS AS MAJORITY OF MOISTURE AND
LIFT ASSOCIATED WITH THE MID ATLANTIC SYSTEM ARE FORECAST TO REMAIN TO
OUR SW.
ONSHORE FLOW CONTINUES THROUGH SUN WITH TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL LOW IN MID-ATLANTIC FINALLY GETS ABSORBED INTO MEAN
FLOW SUN NIGHT AND MOVES ACROSS MON MORNING. THIS WILL BE THE BEST
CHC OF THE LOCAL AREA SEEING ANY PRECIP FROM THIS SYSTEM. ELEVATED
INSTABILITY ALSO DEVELOPS SO TSTMS WILL BE POSSIBLE. FCST MODELS
SHOW A STRONGER UPPER LVL TROUGH APPROACHING WITH A HIGHER
PROBABILITY OF SCT SHOWERS AND TSTMS...MAINLY FROM MONDAY AFTN
THROUGH NOON TUESDAY. AS ALWAYS...TIMING THIS FRONTAL PASSAGE WILL
BE A CHALLENGE. AS THIS FRONT MOVES INTO A WARM...MOIST UNSTABLE
MARITIME TROPICAL AIR MASS...A FEW STORMS COULD PRODUCE HVY RAIN
AND STRONG GUSTY WINDS.
TUE NIGHT THROUGH FRI...FCST MODELS SHOW HIGH PRES MVG SE TOWARD
THE AREA COURTESY OF A WELL DEFINED HIGH AMPLITUDE UPSTREAM RIDGE
ACROSS THE WESTERN U.S. THIS WILL REPLACE THE MARITIME TROPICAL AIR
MASS WITH A FRESH AND DRIER CONTINENTAL POLAR AIR MASS.
REGARDING THE FORECAST FOR ISAAC...PLEASE REFER TO THE LATEST
NATIONAL HURRICANE CENTER FORECASTS. AT THIS TIME...IT APPEARS THAT
THE REMNANTS FROM ISAAC MAY PASS SOUTH OF THE LOCAL AREA NEXT
THURSDAY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN NEAR THE CANADIAN MARITIMES THROUGH THE
DAY TODAY.
EXPECT AREAS OF MVFR OR IFR CONDITIONS IN FOG EARLY THIS
MORNING...MAINLY OUTSIDE OF NYC METRO TERMINALS. OTHERWISE...VFR
WITH MID AND HIGH CLOUDS TODAY. WINDS REMAIN LIGHT EARLY THIS
MORNING...THEN INCREASE FROM THE EAST/SOUTHEAST CLOSE TO 10 KTS BY
AFTERNOON. CANNOT RULE OUT AN ISOLATED SHOWER THIS AFTERNOON...BUT
DO NOT EXPECT COVERAGE TO BE HIGH ENOUGH TO INCLUDE IN THE
FORECAST AT THIS TIME.
OUTLOOK FOR 06Z SUNDAY THROUGH WED...
.SUNDAY...MAINLY VFR. ISOLATED SHOWERS/TSTMS POSSIBLE WITH BRIEF
MVFR OR LOWER CONDS.
.MON-TUE...MVFR OR LOWER CONDS POSSIBLE...ESPECIALLY IN ANY
SHOWERS/TSTMS THAT DEVELOP AS A COLD FRONT APPROACHES.
BEST CHANCES FOR THESE LOWER CONDITIONS TUE INTO TUE NIGHT.
.WED...VFR.
&&
.MARINE...
AS HIGH PRESSURE MOVES AROUND THE CANADIAN MARITIMES AND OFF THE NEW
ENGLAND COAST THROUGH THE REMAINDER OF THE WEEKEND...EXPECT A
PERSISTENT EASTERLY WIND FLOW ACROSS THE LOCAL WATERS. THESE
EASTERLY WINDS WILL SHIFT AROUND THE SOUTH AND SOUTHWEST LATER MONDAY
AND MONDAY NIGHT. THIS WIND SHIFT WILL OCCUR AS THE CENTER OF THE
HIGH DRIFTS EAST AND A COLD FRONT APPROACHES FROM THE NORTHWEST.
THE COLD FRONT WILL PASS ACROSS THE WATERS TUESDAY...FOLLOWED BY
HIGH PRESSURE THROUGH MID WEEK.
SEAS SLOWLY BUILD THIS WEEKEND IN RESPONSE TO THE EASTERLY FLOW...BUT
DO EXPECT WINDS AND SEAS TO REMAIN JUST UNDER SCA CRITERIA.
SEAS SHOULD THEN SETTLE AND REMAIN AROUND 3 OR 4 FT THROUGH THE
EARLY PART OF THE WEEK ACROSS THE OCEAN WATERS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE WEEKEND.
MON THROUGH TUE...SCT HEAVIER SHOWERS AND TSTMS COULD PRODUCE 1/2 TO
1 INCH OF RAIN IN ADVANCE OF AN APPROACHING COLD FRONT. ISOLATED
URBAN FLOODING IS POSSIBLE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
424 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE CENTERED NEAR THE CANADIAN MARITIMES WILL TRACK
EASTWARD TODAY THEN BECOMES ELONGATED BACK TOWARDS THE NEW ENGLAND
COAST TONIGHT AND SUNDAY. MEANWHILE...AN UPPER LEVEL LOW OVER THE
MID ATLANTIC WILL MOVE SLOWLY NORTHEAST TOWARD THE AREA. A COLD
FRONT IS FORECAST TO MOVE SOUTHEAST CROSS THE AREA TUESDAY
FOLLOWED BY HIGH PRESSURE WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MID ATLANTIC
STATES WILL CONTINUE TO SEND ABUNDANT MID AND HIGH LEVEL CLOUDS
INTO THE AREA TODAY. SOME AREAS MAY EXPERIENCE FILTERED SUNSHINE
THIS MORNING BUT IT WILL EVENTUALLY GIVE WAY TO THICKER CLOUDS
WITH MOSTLY CLOUDY SKIES DEVELOPING BY AFTERNOON.
VORT ENERGY FROM THIS LOW WILL ADVANCE TOWARDS THE AREA TODAY. 00Z
OKX SOUNDING INDICATES A DRY PROFILE HOWEVER...AN ONSHORE FLOW
WILL BE INCREASING LOW LEVEL MOISTURE AND THERE COULD BE A FEW
SHOWERS AROUND. LATEST HRRR DOES INDICATE SOME LIGHT ECHOES EARLY
THIS AFTERNOON ACROSS WESTERN PORTIONS OF THE CWA. HAVE MAINTAINED
SCHC POPS AS A RESULT. HAVE REMOVED MENTION OF THUNDER WITH LITTLE
INSTABILITY FORECAST AND EQL LEVEL FORECAST TO BE AROUND -10C.
SUBSIDENCE FROM DEPARTING HIGH PRES MAY BE ENOUGH TO KEEP EASTERN
AREAS DRY TODAY SO NO POPS.
MOS GUIDANCE WAS CLOSE ON HIGH TEMPS TODAY AND USED A BLEND.
THERE IS A MODERATE RISK OF RIP CURRENTS AT ATLANTIC OCEAN BEACHES
TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
UPPER LEVEL RIDGING OVER THE ATLANTIC BUILDS BACK TOWARDS THE
EAST COAST TONIGHT WITH THE UPPER LEVEL LOW WEAKENING. HAVE GONE
WITH A DRY FORECAST UNTIL LATE TONIGHT THROUGH SUNDAY WITH ONLY SCHC
POPS RETURNING ACROSS WESTERN AREAS AS MAJORITY OF MOISTURE AND
LIFT ASSOCIATED WITH THE MID ATLANTIC SYSTEM ARE FORECAST TO REMAIN TO
OUR SW.
ONSHORE FLOW CONTINUES THROUGH SUN WITH TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL LOW IN MID-ATLANTIC FINALLY GETS ABSORBED INTO MEAN
FLOW SUN NIGHT AND MOVES ACROSS MON MORNING. THIS WILL BE THE BEST
CHC OF THE LOCAL AREA SEEING ANY PRECIP FROM THIS SYSTEM. ELEVATED
INSTABILITY ALSO DEVELOPS SO TSTMS WILL BE POSSIBLE. FCST MODELS
SHOW A STRONGER UPPER LVL TROUGH APPROACHING WITH A HIGHER
PROBABILITY OF SCT SHOWERS AND TSTMS...MAINLY FROM MONDAY AFTN
THROUGH NOON TUESDAY. AS ALWAYS...TIMING THIS FRONTAL PASSAGE WILL
BE A CHALLENGE. AS THIS FRONT MOVES INTO A WARM...MOIST UNSTABLE
MARITIME TROPICAL AIR MASS...A FEW STORMS COULD PRODUCE HVY RAIN
AND STRONG GUSTY WINDS.
TUE NIGHT THROUGH FRI...FCST MODELS SHOW HIGH PRES MVG SE TOWARD
THE AREA COURTESY OF A WELL DEFINED HIGH AMPLITUDE UPSTREAM RIDGE
ACROSS THE WESTERN U.S. THIS WILL REPLACE THE MARITIME TROPICAL AIR
MASS WITH A FRESH AND DRIER CONTINENTAL POLAR AIR MASS.
REGARDING THE FORECAST FOR ISAAC...PLEASE REFER TO THE LATEST
NATIONAL HURRICANE CENTER FORECASTS. AT THIS TIME...IT APPEARS THAT
THE REMNANTS FROM ISAAC MAY PASS SOUTH OF THE LOCAL AREA NEXT
THURSDAY.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN NEAR THE CANADIAN MARITIMES THROUGH THE
DAY TODAY.
EXPECT AREAS OF MVFR OR IFR CONDITIONS IN FOG EARLY THIS
MORNING...MAINLY OUTSIDE OF NYC METRO TERMINALS. OTHERWISE...VFR
WITH MID AND HIGH CLOUDS TODAY. WINDS REMAIN LIGHT EARLY THIS
MORNING...THEN INCREASE FROM THE EAST/SOUTHEAST CLOSE TO 10 KTS BY
AFTERNOON. CANNOT RULE OUT AN ISOLATED SHOWER THIS AFTERNOON...BUT
DO NOT EXPECT COVERAGE TO BE HIGH ENOUGH TO INCLUDE IN THE
FORECAST AT THIS TIME.
OUTLOOK FOR 06Z SUNDAY THROUGH WED...
.SUNDAY...MAINLY VFR. ISOLATED SHOWERS/TSTMS POSSIBLE WITH BRIEF
MVFR OR LOWER CONDS.
.MON-TUE...MVFR OR LOWER CONDS POSSIBLE...ESPECIALLY IN ANY
SHOWERS/TSTMS THAT DEVELOP AS A COLD FRONT APPROACHES.
BEST CHANCES FOR THESE LOWER CONDITIONS TUE INTO TUE NIGHT.
.WED...VFR.
&&
.MARINE...
AS HIGH PRESSURE MOVES AROUND THE CANADIAN MARITIMES AND OFF THE NEW
ENGLAND COAST THROUGH THE REMAINDER OF THE WEEKEND...EXPECT A
PERSISTENT EASTERLY WIND FLOW ACROSS THE LOCAL WATERS. THESE
EASTERLY WINDS WILL SHIFT AROUND THE SOUTH AND SOUTHWEST LATER MONDAY
AND MONDAY NIGHT. THIS WIND SHIFT WILL OCCUR AS THE CENTER OF THE
HIGH DRIFTS EAST AND A COLD FRONT APPROACHES FROM THE NORTHWEST.
THE COLD FRONT WILL PASS ACROSS THE WATERS TUESDAY...FOLLOWED BY
HIGH PRESSURE THROUGH MID WEEK.
SEAS SLOWLY BUILD THIS WEEKEND IN RESPONSE TO THE EASTERLY FLOW...BUT
DO EXPECT WINDS AND SEAS TO REMAIN JUST UNDER SCA CRITERIA.
SEAS SHOULD THEN SETTLE AND REMAIN AROUND 3 OR 4 FT THROUGH THE
EARLY PART OF THE WEEK ACROSS THE OCEAN WATERS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE WEEKEND.
MON THROUGH TUE...SCT HEAVIER SHOWERS AND TSTMS COULD PRODUCE 1/2 TO
1 INCH OF RAIN IN ADVANCE OF AN APPROACHING COLD FRONT. ISOLATED
URBAN FLOODING IS POSSIBLE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
440 PM EDT SAT AUG 25 2012
.SYNOPSIS...
20Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS OUR REGION LOCATED UNDER A
MID/UPPER LEVEL WEAKNESS IN THE HEIGHT FIELD TO THE WEST OF A RIDGE
OFF THE SE CONUS. STILL DEALING WITH A WEAK DISTURBANCE NEAR THE
FLORIDA STRAITS THAT IS SUPPORTING A BROAD AREA OF RAIN/THUNDER OVER
THE SE/S FL PENINSULA. MOST OF THE RAINFALL SHOULD CONTINUE TO
REMAIN EAST AND SOUTH OF OF LEE/CHARLOTTE COUNTIES AS SPEED
CONVERGENCE FOCUS WEAKENS INLAND FROM THE EAST COAST. A FEW
ADDITIONAL SCT SHOWERS ARE ADVANCING WESTWARD ACROSS THE PENINSULA
AND WILL EFFECT THE TAMPA BAY AREA UP THROUGH THE NATURE COAST ZONES
THE NEXT SEVERAL HOURS. SHOULD SEE THESE STORMS DISSIPATE AS WE HEAD
INTO THE EVENING HOURS. ANY SHOWERS/STORMS THAT DO OCCUR IN THE
FORECAST AREA ARE NOT ASSOCIATED WITH ANY OUTER-BANDS OF ISAAC. THIS
IS A SEPARATE MID-LEVEL FEATURE WHICH WILL BE PASSING OUT IN THE SE
GULF LATER TODAY/TONIGHT.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN A 1022MB RIDGE CENTER
OVER THE CAROLINAS...AND THE LOW PRESSURE ASSOCIATED WITH TS ISAAC
DOWN OVER THE EASTERN TIP OF CUBA. THE LOCAL GRADIENT IS TIGHTENING
BETWEEN THESE 2 FEATURES. A MORE MESO-SCALE ANALYSIS SHOWS A FAIRLY
SHARP INVERTED TROUGH ALONG THE FLORIDA EAST COAST WHICH IS ALSO
HELPING TO FOCUS THE LIFT FOR SHOWERS/STORMS TO OUR EAST AND SOUTH.
&&
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
TONIGHT...
CURRENT THINKING IS THAT RAIN CHANCES WILL FALL (EVEN FOR
THE FAR SOUTH) INTO THE OVERNIGHT HOURS AS THE DISTURBANCE MENTIONED
ABOVE EXITS THE REGION. WITH SOME RESIDUAL LINGERING SYNOPTIC
SUPPORT FOR LIFT AND ADDED SPEED CONVERGENCE SHOWERS MOVING INLAND
FROM THE FL EAST COAST WILL KEEP A LOW END CHANCE FOR SHOWERS IN THE
GRIDS DOWN TOWARD FORT MYERS. ELSEWHERE AFTER ANY SCT EVENING
SHOWERS HAVE FADED...WILL ANTICIPATE A MAINLY DRY OVERNIGHT.
SUNDAY...
WILL BE WATCHING TROPICAL STORM ISAAC CONTINUE TO MOVE TOWARD THE
NORTHWEST ALONG OR NEAR THE NORTHERN COAST OF CUBA AND THEN THROUGH
THE FLORIDA STRAITS. MODEL GUIDANCE IS FAIRLY CLUSTERED THROUGH THIS
POINT BRINGING THE STORM CENTER TO NEAR THE FLORIDA KEYS SUNDAY
EVENING. OUTER RAINBANDS ASSOCIATED WITH ISAAC ARE EXPECTED TO BEGIN
IMPACTING ZONES TO THE SOUTH OF I-4 BEFORE THE END OF THE DAY WITH
THE HEAVIEST AND MOST WIDESPREAD RAINFALL POTENTIAL INCREASING THE
FURTHER SOUTH AND SOUTHEAST ONE TRAVELS. IN ADDITION TO THESE OUTER
RAINBANDS...THE LOCAL GRADIENT WILL CONTINUE TO TIGHTEN BETWEEN THE
STORM TO OUR SOUTH AND A RIDGE OF HIGH PRESSURE TO THE NORTH. JUST
HOW TIGHT THE GRADIENT EVENTUALLY BECOMES WILL DEPEND ON THE
STRENGTH/ORGANIZATION OF ISAAC...BUT IT IS LIKELY TO BE A RATHER
GUSTY DAY. THE CURRENT FORECAST WOULD SUPPORT SEEING TROPICAL STORM
FORCE GUSTS DOWN TOWARD LEE COUNTY BEFORE THE DAY IS OVER ASSOCIATED
WITH SOME OF THE RAINBANDS. AROUND THE TAMPA BAY AREA AND NORTHWARD
UP THE NATURE COAST...A FEW SHOWERS/ISOLATED STORMS ARE POSSIBLE
DURING THE AFTERNOON...HOWEVER IN GENERAL SUNDAY DOES NOT LOOK TO BE
A WET DAY THIS FAR NORTH AND WEST.
SUNDAY NIGHT...ISAAC IS FORECAST TO PROCEED INTO THE SOUTHEAST GULF
OF MEXICO. IT WILL BE DURING THIS PERIOD THAT BOTH THE HEAVIER
RAINBANDS AND POTENTIAL FOR TROPICAL STORM FORCE WINDS WILL BE
EXPANDING NORTHWARD INTO THE TAMPA BAY/I-4 CORRIDOR. FOR OUR
SOUTHERN COASTAL ZONES TO THE SOUTH OF SARASOTA...THIS IS WHEN WE
MIGHT BEGIN TO SEE SOME POTENTIAL SURGE PROBLEMS AS WELL AS THE
STORM CENTER PASSES AND PREVIOUS OFFSHORE WINDS COME AROUND MORE TO
THE SOUTH AND SOUTHWEST. PLEASE SEE THE LATEST HURRICANE LOCAL
STATEMENT (MIAHLSTBW) ISSUED BY THIS OFFICE FOR MORE SURGE
INFORMATION FOR LEE AND CHARLOTTE COUNTIES.
MONDAY/MONDAY NIGHT...ISAAC IS FORECAST TO BE MOVING TOWARD THE
NORTHWEST ACROSS THE EASTERN GULF OF MEXICO. THERE REMAINS SOME
DIFFERENCE IN THE GUIDANCE REGARDING THE TRACK OF ISAAC AND JUST HOW
FAR OFF THE FLORIDA WEST COAST THE STORM WILL PASS. AT THIS TIME THE
THREAT FOR PERIODS OF HEAVY RAIN AND TROPICAL STORM FORCE WINDS
REMAIN IN THE GRIDS. THE POTENTIAL FOR SOME COASTAL PROBLEMS RELATED
TO SURGE WILL ALSO BE DEVELOPING UP THE COAST TOWARD TAMPA BAY AND
THE NATURE COAST. BASED ON THE CURRENT UNCERTAINTY IN THE STORM
TRACK AND INTENSITY...THE FORECAST WILL CONTINUE TO BE REFINED WITH
FUTURE HURRICANE CENTER ADVISORIES.
ONE FINAL NOTE...DEPENDING ON THE TRACK OF ISAAC...FLOOD WATCHES MAY
BECOME NECESSARY FOR ALL OR PORTIONS OF THE AREA LATER TONIGHT OR
SUNDAY.
&&
.AVIATION...
A FEW STORMS ARE DEVELOPING OVER THE INTERIOR AND WILL MOVE WESTWARD
TOWARD THE TERMINALS THIS AFTERNOON. COVERAGE IS LOW SO NO TEMPO
GROUPS PLANNED AT THIS TIME. OTHERWISE STILL VFR NEXT 24 HOURS WITH
MAIN IMPACTS FROM ISAAC HOLDING OFF UNTIL AFTER 18Z SUNDAY.
&&
.MARINE...
TROPICAL STORM OR HURRICANE WATCHES HAVE BEEN ISSUED FOR THE COASTAL
WATERS FROM BONITA BEACH TO THE SUWANNEE RIVER. THE FORECAST WATERS
WILL REMAIN BETWEEN A RIDGE OF HIGH PRESSURE TO OUR NORTH AND
TROPICAL STORM ISAAC APPROACHING FROM THE SOUTHEAST. THE GRADIENT
BETWEEN THESE 2 SYSTEMS WILL CONTINUE TO TIGHTEN THROUGH SUNDAY WITH
ISAAC FORECAST TO MOVE INTO AND THROUGH THE EASTERN GULF OF MEXICO
DURING THE EARLY PORTION OF THE WEEK. FOR ADDITIONAL INFORMATION ON
TROPICAL STORM ISAAC...SEE THE LATEST ADVISORIES BEING ISSUED BY THE
NATIONAL HURRICANE CENTER.
&&
.HYDROLOGY...
FLOOD WARNINGS CONTINUE ON THE LITTLE MANATEE RIVER AND CYPRESS
CREEK. THE GROUND REMAINS SATURATED FROM RECENT HEAVY RAINS...AND
ADDITIONAL HEAVY RAIN EXPECTED FROM T.S. ISAAC MAY CAUSE
SIGNIFICANT FLOODING OF RIVERS OVER WEST CENTRAL FLORIDA MONDAY
INTO THE MIDDLE OF NEXT WEEK. FLOODING OF LOW LYING AND FLOOD
PRONE AREAS...WITH SIGNIFICANT FLOODING OF STREETS IN URBAN AREAS
IS POSSIBLE. THE GREATEST THREAT WILL BE SUNDAY NIGHT THROUGH
MONDAY NIGHT...BUT COULD EXTEND INTO TUESDAY OVER THE NORTHERN
HALF OF THE AREA DEPENDING ON THE EVENTUAL TRACK OF ISAAC.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 76 90 78 84 / 20 50 70 70
FMY 75 86 77 85 / 30 90 80 70
GIF 74 91 75 85 / 20 50 70 70
SRQ 75 91 78 87 / 20 50 70 70
BKV 70 90 79 86 / 20 50 70 70
SPG 78 89 79 85 / 20 40 70 70
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...TROPICAL STORM WATCH FOR CHARLOTTE-DESOTO-HARDEE-HIGHLANDS-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-POLK-SARASOTA.
GULF WATERS...TROPICAL STORM WATCH FOR ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE
RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60
NM.
HURRICANE WATCH FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD
TO TARPON SPRINGS OUT 20 TO 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
HYDROLOGY...OGLESBY
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
935 AM EDT SAT AUG 25 2012
.UPDATE (REST OF TODAY)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS OUR REGION LOCATED UNDER A
MID/UPPER LEVEL WEAKNESS IN THE HEIGHT FIELD BETWEEN RIDGING OVER
THE CENTRAL/WESTERN GULF OF MEXICO...AND ANOTHER RIDGE OFF THE SE
CONUS. SEEING A WEAK DISTURBANCE NEAR THE FLORIDA STRAITS THAT IS
SUPPORTING A BROAD AREA OF RAIN/THUNDER OVER THE SE/S FL PENINSULA
THIS MORNING. GUIDANCE IS HAVING A DIFFICULT TIME WITH THIS
FEATURE...AND WILL CONTINUE TO MAKE FORECAST ADJUSTMENTS TO THE RAIN
CHANCES DOWN TOWARD CHARLOTTE AND LEE COUNTIES INTO THE AFTERNOON
HOURS. MOST OF THE RAINFALL SHOULD REMAIN EAST AND SOUTH OF OF
LEE/CHARLOTTE COUNTIES AS SPEED CONVERGENCE FOCUS WEAKENS INLAND
FROM THE EAST COAST. ANY SHOWERS/STORMS THAT DO OCCUR ARE NOT
ASSOCIATED WITH ANY OUTER-BANDS OF ISAAC. THIS IS A SEPARATE
MID-LEVEL FEATURE WHICH WILL BE PASSING OUT IN THE SE GULF LATER
TODAY/TONIGHT.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN A 1022MB RIDGE CENTER
OVER THE CAROLINAS...AND THE LOW PRESSURE ASSOCIATED WITH TS ISAAC
DOWN TOWARD THE EASTERN TIP OF CUBA. THE LOCAL GRADIENT IS
TIGHTENING BETWEEN THESE 2 FEATURES WHICH WILL ALLOW FOR SOME GUSTY
WINDS OUT OF THE EAST THIS AFTERNOON. ANALYSIS SHOWS A MORE
MESOSCALE...BUT SHARP INVERTED TROUGH ALONG THE FLORIDA EAST COAST
WHICH IS ALSO HELPING TO FOCUS THE LIFT FOR SHOWERS/STORMS TO OUR
EAST AND SOUTH.
CURRENT THINKING IS THAT RAIN CHANCES WILL FALL (EVEN FOR THE FAR
SOUTH) LATER TODAY INTO THE OVERNIGHT HOURS AS THE DISTURBANCE
MENTIONED ABOVE EXITS THE REGION. WE WILL THEN BEGIN TO AWAIT THE
ARRIVAL OF RAINBANDS FROM THE SOUTHEAST ASSOCIATED WITH ISAAC. GOOD
MODEL AGREEMENT THAT THESE FIRST OUTER-BANDS WILL ARRIVE DOWN TOWARD
LEE/CHARLOTTE COUNTIES DURING THE DAYLIGHT HOURS OF SUNDAY.
&&
.SHORT TERM (TODAY-MONDAY)...
LEANING TOWARD SLIGHTLY HIGHER POPS OVERNIGHT OVER THE SOUTHERN HALF
OF THE FORECAST AREA WITH BEST CHANCE OF A SHOWER IN THE FORT MYERS
AREA. BIG QUESTIONS ARISE SUNDAY INTO MONDAY ON EVENTUAL TRACK AND
STRENGTH OF ISAAC AS IT MOVES THROUGH THE FLORIDA STRAITS AND OVER
THE EASTERN GULF OF MEXICO. GIVEN LATEST NHC TRACK AND INTENSITY
FORECAST...EXPECT NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS TO
SPREAD OVER SOUTHWEST FLORIDA AND SOUTHERN INTERIOR SUNDAY
MORNING...AND AS FAR NORTH AS THE I-4 CORRIDOR SUNDAY AFTERNOON WITH
WIDESPREAD HEAVY SHOWERS DEVELOPING OVER SOUTHWEST FLORIDA. PERIODS
OF HEAVY RAIN AND STRONG GUSTY WINDS SUNDAY NIGHT INTO MONDAY AS
ISAAC MOVES OVER THE EASTERN GULF. STILL TOO EARLY FOR SPECIFICS AS
EVENTUAL TRACK AND INTENSITY REMAIN UNCERTAIN...BUT GOOD CHANCE AS
ISAAC MOVES INTO THE EASTERN GULF THAT BAND OF HEAVY RAIN WILL
DEVELOP OVER WEST CENTRAL AND SOUTHWEST FLORIDA WITH HIGHEST
RAINFALL TOTALS NEAR THE COAST. A FLOOD WATCH MAY BE NEEDED ON
SUNDAY AND MONDAY. POTENTIAL FOR 5 TO 10 INCHES OF RAIN WITH LOCALLY
HIGHER AMOUNTS IF TRAINING DEVELOPS WITH SPIRAL BANDS EAST OF THE
CENTER. WILL RUN BELOW MOS GUIDANCE WITH TEMPERATURES SUNDAY AND
MONDAY FOR MOST AREAS AS INCREASING CLOUD COVER AND AREAS OF RAIN
SHOULD KEEP TEMPS COOLER.
&&
.AVIATION...
WINDS WILL BECOME GUSTY FROM THE NORTHEAST OR EAST. AREA OF SHOWERS
MOVING ACROSS SOUTH FLORIDA COULD IMPACT FMY...RSW AND PGD TODAY.
MOST TERMINALS STAY VFR WITH JUST A FEW VCTS IN THE AFTERNOON.
&&
.MARINE...
INCREASING WINDS AND SEAS TODAY AND SUNDAY AS THE GRADIENT
TIGHTENS OVER THE WATERS AHEAD OF ISAAC. SIGNIFICANT INCREASE IN
WAVES AND SEAS SUNDAY NIGHT AND MONDAY AS ISAAC MOVES OVER THE
EASTERN GULF WATERS. SEAS MAY NEED TO BE ADJUSTED HIGHER IF ISAAC
STRENGTHENS MORE THAN CURRENTLY FORECAST. WINDS AND SEAS WILL
GRADUALLY SUBSIDE TUESDAY AND WEDNESDAY FROM SOUTH TO NORTH AS ISAAC
PULLS AWAY FROM THE AREA.
&&
.HYDROLOGY...
FLOOD WARNINGS CONTINUE ON THE LITTLE MANATEE RIVER AND CYPRESS
CREEK. THE GROUND REMAINS SATURATED FROM RECENT HEAVY RAINS...AND
ADDITIONAL HEAVY RAIN EXPECTED FROM T.S. ISAAC MAY CAUSE
SIGNIFICANT FLOODING OF RIVERS OVER WEST CENTRAL FLORIDA MONDAY
INTO THE MIDDLE OF NEXT WEEK. FLOODING OF LOW LYING AND FLOOD
PRONE AREAS...WITH SIGNIFICANT FLOODING OF STREETS IN URBAN AREAS
IS POSSIBLE. THE GREATEST THREAT WILL BE SUNDAY NIGHT THROUGH
MONDAY NIGHT...BUT COULD EXTEND INTO TUESDAY OVER THE NORTHERN
HALF OF THE AREA DEPENDING ON THE EVENTUAL TRACK OF ISAAC.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 93 78 89 78 / 30 20 60 60
FMY 92 77 86 77 / 60 40 80 80
GIF 92 76 88 76 / 30 20 60 60
SRQ 93 78 89 78 / 50 20 60 80
BKV 93 73 91 74 / 30 20 40 60
SPG 90 80 89 80 / 30 20 60 80
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
PREVIOUS DISCUSSION/HYDROLOGY...OGLESBY
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
207 AM CDT SAT AUG 25 2012
.DISCUSSION...
324 PM CDT
TODAY THROUGH SATURDAY NIGHT...
AN UPPER LEVEL DISTURBANCE IS SLOWLY PASSING THROUGH NORTHERN
WISCONSIN AND WILL CONTINUE EASTWARD THROUGH THE NORTHERN GREAT
LAKES THIS EVENING. SOME OF THE SHORT TERM MODELS INDICATE
SCATTERED SHOWERS WILL DEVELOP ACROSS NORTHERN ILLINOIS...BUT WILL
CONTINUE WITH A DRY FORECAST THIS AFTERNOON. LATEST RAP ANALYSIS
INDICATES AMPLE CAPE AND LOW LEVEL LAPSE RATES NEAR DRY
ADIABATIC...HOWEVER SUSPECTING THE RAP ANALYSIS MAY BE OVER
ESTIMATING CAPE VALUES. ALSO TOOK INTO CONSIDERATION THAT THE UPPER
LEVEL WAVE IS WELL NORTH OF THE CWA...AND CONVECTION/SHOWERS OVER
LAKE MICHIGAN ARE ASSOCIATED WITH AN AREA OF 850 HPA WARM AIR
ADVECTION. SCT CU IS BEGINNING TO DEVELOP ROUGHLY ALONG THE I-55
CORRIDOR.
SKIES CLEAR TONIGHT AND EXPECTING A COMFORTABLE NIGHT DESPITE LOW
90S BEING REPORTED ACROSS THE CWA THIS AFTERNOON. OVERNIGHT LOWS
WILL BE IN THE MID 60S...EXCEPT FOR LOW 70S DOWNTOWN. SATURDAY WILL
BE MUCH LIKE TODAY...WITH A DRY AND HOT FORECAST. RAISED INHERITED
TEMPS SUCH THAT TOMORROWS HIGHS ARE A DEGREE OR TWO WARMER THAN
TODAY. COULD EVEN SEE AREAS IN THE SOUTHERN PORTIONS OF THE CWA
BEING A BIT WARMER THAN CURRENTLY FORECAST. MODEL SOUNDINGS
INDICATES THERE WILL BE PLENTY OF MIXING TOMORROW...THEREFORE WENT
WITH DEW POINTS SLIGHTLY LOWER THAN PREVIOUSLY FORECAST. MIN RH
VALUES WILL BE IN THE MID TO UPPER 20 PERCENT RANGE...BUT WITH LIGHT
WINDS FORECAST NOT ANTICIPATING ANY FIRE WEATHER HEADLINES. THAT
BEING SAID A FEW LOCATIONS MAY REACH RED FLAG CRITERIA...AS RFD DID
TODAY. KEPT PREVIOUS MIN TEMPS FOR SATURDAY NIGHT WITH MID TO UPPER
60S IN THE OUTLYING AREAS...AND IN THE LOW 70S DOWNTOWN.
SUNDAY THROUGH MONDAY NIGHT...
LOW PRESSURE CURRENTLY OVER SOUTHERN SASKATCHEWAN AND THE NORTHERN
GREAT PLAINS WILL MOVE EASTWARD ACROSS SOUTHERN CANADA THROUGH THE
WEEKEND. THE LOWS COLD FRONT PASSES THROUGH THE CWA LATE SUNDAY
NIGHT INTO MONDAY MORNING. PRECIP AHEAD OF THE COLD FRONT WAS THE
MAIN FORECAST CHALLENGE TODAY. THE NAM AND GFS LOOKED A BIT FAST
WHILE THE ECMWF HAS BEEN SLOWING THE PROGRESSION OF THE SHOWERS
AND THUNDERSTORMS THE PAST FEW RUNS. WENT WITH A NAM/ECMWF MIX
THAT WAS VERY SIMILAR TO THE PREVIOUS FORECASTS TIMING...WITH
PRECIP REACHING THE WESTERN EDGE OF THE CWA LATE SATURDAY NIGHT.
THAT BEING SAID...THE MODELS ARE INDICATING THE INITIAL UPPER
LEVEL VORTICITY STREAMER ASSOCIATED WITH FIRST WAVE OF PRECIP WILL
BE STRETCHED NORTH TO SOUTH AND FRACTURE SOMEWHERE OVER WISCONSIN.
THE SOUTHERN PART OF THE VORT STREAMER WILL THEN PROGRESS EASTWARD
BRINGING MUCH NEEDED RAIN TO NORTHERN ILLINOIS. CONFIDENCE IS
MEDIUM WITH THE TIMING AND PROGRESSION OF THE PRECIP...BUT HIGH
REGARDING THE POSSIBILITY OF IT BEING A SIGNIFICANT RAINFALL.
PW VALUES WILL BE AROUND TO SLIGHTLY ABOVE 2 INCHES AHEAD OF THE
FRONT...WHICH IS AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL FOR
AUGUST. THEREFORE SUBSTANTIAL RAINFALL IS POSSIBLE AND AS MENTIONED
IN THE PREVIOUS DISCUSSION...TRAINING CELLS COULD CAUSE ISOLATED
WATER PROBLEMS.
TEMPS ON SUNDAY WILL BE MUCH COOLER WITH AREAS WEST OF I-55 IN THE
UPPER 70S...AND LOW TO MID 80S EXPECTED EAST OF I-55. TEMPS REBOUND
SLIGHTLY ON MONDAY WITH HIGHS IN THE LOW TO MID 80S.
EXTENDED...TUESDAY THROUGH FRIDAY...
HIGH PRESSURE MOVES IN BEHIND THE COLD FRONT LEADING TO ANOTHER
EXTENDED PERIOD OF DRY WEATHER. TEMPS INCREASE THROUGHOUT THE
EXTENDED...AND COULD BE EVEN WARMER THAN FORECAST. EXPECTING UPPER
80S TO QUITE POSSIBLY 90S BY LATE NEXT WEEK.
JEE
&&
.FIRE WEATHER...
428 PM CDT
RH VALUES DROPPED INTO THE 20 PERCENT RANGE ACROSS PARTS OF THE
AREA TODAY...AND SIMILAR CONDITIONS ARE EXPECTED TOMORROW.
TEMPERATURES TOMORROW WILL ONCE AGAIN BE IN THE LOW TO MID
90S...WITH LOWER DEW POINTS THAN TODAY. AMPLE MIXING WILL LIKELY
LEAD TO DEW POINTS DROPPING INTO THE LOW 50S SATURDAY AFTERNOON.
MIN RH VALUES WILL BE IN THE LOW TO MID 20 PERCENT RANGE...HOWEVER
WIND SPEEDS WILL BE AROUND 10 MPH. WIND GUSTS WILL DEVELOP IN THE
AFTERNOON WITH GUSTS UP TO 20 MPH EXPECTED WEST OF I-39...AND
GUSTS AROUND 15 MPH EXPECTED EAST OF I-39. FUEL MOISTURE LEVELS
ARE ABOVE 10 PERCENT FOR MUCH OF NORTHERN ILLINOIS...WHILE AREAS
EAST OF I-55 HAVE 10-HOUR FUELS LESS THAN 10 PERCENT. THEREFORE
TWO OF THE THREE RED FLAG CONDITIONS MAY BE MET IN ISOLATED
LOCATIONS...SIMILAR TO TODAY...BUT NOT EXPECTING ALL THREE RED
FLAG CONDITIONS TO BE MET. THEREFORE NO FIRE WEATHER HEADLINES ARE
ANTICIPATED.
A COLD FRONT MOVES THROUGH THE REGION LATE SATURDAY NIGHT INTO
SUNDAY BRINGING A WIDESPREAD SOAKING RAIN AND COOLER TEMPERATURES
WITH IT.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SPORADIC GUSTS TO 15 KT THIS AFTERNOON.
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE WILL REMAIN IN CONTROL TO THE EAST OF THE REGION
TODAY WITH LOW PRESSURE BECOMING BETTER ORGANIZED ACROSS THE
CENTRAL PLAINS. WITH SUCH A PATTERN...SOUTHERLY WINDS WILL PREVAIL
AND SHOULD BE AT A SIMILAR MAGNITUDE TO THOSE SEEN ON FRIDAY. A
FEW HIGH BASED CU ARE POSSIBLE...AND ANY LAKE BREEZE IS
ANTICIPATED TO REMAIN TO THE EAST OF ORD AND MDW. AS THE LOW
PRESSURE TROUGH INCHES EAST TONIGHT...UPPER LEVEL CLOUDS WILL BE
ON THE INCREASE. THESE CLOUDS WILL LOWER ON SUNDAY WITH RAIN
LIKELY BY AFTERNOON INTO THE EVENING...WITH POTENTIALLY MVFR BASES
DEVELOPING.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE ON ALL FORECAST ELEMENTS.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE TSRA DURING A.M. THEN LIKELY DURING P.M.
PREVAILING VFR BUT LOCAL MVFR OR IFR WITH ANY TS.
MONDAY...SLIGHT CHANCE TSRA DURING A.M. OTHERWISE VFR THROUGH
THE DAY.
TUESDAY TROUGH THURSDAY...VFR. WX NIL.
MTF/TRS
&&
.MARINE...
205 AM CDT
HIGH PRESSURE PERSISTS OVER THE NORTHEAST U.S. WITH A LOW PRESSURE
TROUGH ACROSS THE PLAINS STATES EASING EASTWARD. SOUTHERLY FLOW WILL
CONTINUE BETWEEN THESE FEATURES ACROSS LAKE MICHIGAN THROUGH THE
DAY SUNDAY. WINDS SHOULD AGAIN TURN EASTERLY OFF THE ILLINOIS
NEARSHORE THIS AFTERNOON AS A LAKE BREEZE DEVELOPS...WHILE WINDS
ALONG THE INDIANA NEARSHORE MAY EVEN BACK TO NORTHEASTERLY FOR A
PERIOD THIS AFTERNOON. AS THE TROUGH SHIFTS EAST OVER THE LAKE BY
LATER SUNDAY...AND A LOW PRESSURE PROGRESSES NORTHEAST ALONG THE
BOUNDARY...WINDS WILL BEGIN TO VEER TOWARD THE WEST SUNDAY NIGHT.
RAIN WITH EMBEDDED THUNDER IS ALSO LIKELY ACROSS THE SOUTHERN HALF
OF THE LAKE BY LATER SUNDAY INTO SUNDAY EVENING. THE COOL AIR PUSH
BEHIND THIS TROUGH WILL NOT BE OVERLY STRONG...AND THUS EXPECT THE
WEST NORTHWEST FLOW TO BE ONLY AROUND 15 KT OR SO FOR MONDAY. HIGH
PRESSURE THEN LOOKS TO BE IN CONTROL FOR A TIME BEFORE WINDS
POTENTIALLY PICK UP LATER NEXT WEEK...ALTHOUGH UNCERTAINTY IS HIGH
AT THIS TIME.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1223 AM CDT SAT AUG 25 2012
.DISCUSSION...
324 PM CDT
TODAY THROUGH SATURDAY NIGHT...
AN UPPER LEVEL DISTURBANCE IS SLOWLY PASSING THROUGH NORTHERN
WISCONSIN AND WILL CONTINUE EASTWARD THROUGH THE NORTHERN GREAT
LAKES THIS EVENING. SOME OF THE SHORT TERM MODELS INDICATE
SCATTERED SHOWERS WILL DEVELOP ACROSS NORTHERN ILLINOIS...BUT WILL
CONTINUE WITH A DRY FORECAST THIS AFTERNOON. LATEST RAP ANALYSIS
INDICATES AMPLE CAPE AND LOW LEVEL LAPSE RATES NEAR DRY
ADIABATIC...HOWEVER SUSPECTING THE RAP ANALYSIS MAY BE OVER
ESTIMATING CAPE VALUES. ALSO TOOK INTO CONSIDERATION THAT THE UPPER
LEVEL WAVE IS WELL NORTH OF THE CWA...AND CONVECTION/SHOWERS OVER
LAKE MICHIGAN ARE ASSOCIATED WITH AN AREA OF 850 HPA WARM AIR
ADVECTION. SCT CU IS BEGINNING TO DEVELOP ROUGHLY ALONG THE I-55
CORRIDOR.
SKIES CLEAR TONIGHT AND EXPECTING A COMFORTABLE NIGHT DESPITE LOW
90S BEING REPORTED ACROSS THE CWA THIS AFTERNOON. OVERNIGHT LOWS
WILL BE IN THE MID 60S...EXCEPT FOR LOW 70S DOWNTOWN. SATURDAY WILL
BE MUCH LIKE TODAY...WITH A DRY AND HOT FORECAST. RAISED INHERITED
TEMPS SUCH THAT TOMORROWS HIGHS ARE A DEGREE OR TWO WARMER THAN
TODAY. COULD EVEN SEE AREAS IN THE SOUTHERN PORTIONS OF THE CWA
BEING A BIT WARMER THAN CURRENTLY FORECAST. MODEL SOUNDINGS
INDICATES THERE WILL BE PLENTY OF MIXING TOMORROW...THEREFORE WENT
WITH DEW POINTS SLIGHTLY LOWER THAN PREVIOUSLY FORECAST. MIN RH
VALUES WILL BE IN THE MID TO UPPER 20 PERCENT RANGE...BUT WITH LIGHT
WINDS FORECAST NOT ANTICIPATING ANY FIRE WEATHER HEADLINES. THAT
BEING SAID A FEW LOCATIONS MAY REACH RED FLAG CRITERIA...AS RFD DID
TODAY. KEPT PREVIOUS MIN TEMPS FOR SATURDAY NIGHT WITH MID TO UPPER
60S IN THE OUTLYING AREAS...AND IN THE LOW 70S DOWNTOWN.
SUNDAY THROUGH MONDAY NIGHT...
LOW PRESSURE CURRENTLY OVER SOUTHERN SASKATCHEWAN AND THE NORTHERN
GREAT PLAINS WILL MOVE EASTWARD ACROSS SOUTHERN CANADA THROUGH THE
WEEKEND. THE LOWS COLD FRONT PASSES THROUGH THE CWA LATE SUNDAY
NIGHT INTO MONDAY MORNING. PRECIP AHEAD OF THE COLD FRONT WAS THE
MAIN FORECAST CHALLENGE TODAY. THE NAM AND GFS LOOKED A BIT FAST
WHILE THE ECMWF HAS BEEN SLOWING THE PROGRESSION OF THE SHOWERS
AND THUNDERSTORMS THE PAST FEW RUNS. WENT WITH A NAM/ECMWF MIX
THAT WAS VERY SIMILAR TO THE PREVIOUS FORECASTS TIMING...WITH
PRECIP REACHING THE WESTERN EDGE OF THE CWA LATE SATURDAY NIGHT.
THAT BEING SAID...THE MODELS ARE INDICATING THE INITIAL UPPER
LEVEL VORTICITY STREAMER ASSOCIATED WITH FIRST WAVE OF PRECIP WILL
BE STRETCHED NORTH TO SOUTH AND FRACTURE SOMEWHERE OVER WISCONSIN.
THE SOUTHERN PART OF THE VORT STREAMER WILL THEN PROGRESS EASTWARD
BRINGING MUCH NEEDED RAIN TO NORTHERN ILLINOIS. CONFIDENCE IS
MEDIUM WITH THE TIMING AND PROGRESSION OF THE PRECIP...BUT HIGH
REGARDING THE POSSIBILITY OF IT BEING A SIGNIFICANT RAINFALL.
PW VALUES WILL BE AROUND TO SLIGHTLY ABOVE 2 INCHES AHEAD OF THE
FRONT...WHICH IS AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL FOR
AUGUST. THEREFORE SUBSTANTIAL RAINFALL IS POSSIBLE AND AS MENTIONED
IN THE PREVIOUS DISCUSSION...TRAINING CELLS COULD CAUSE ISOLATED
WATER PROBLEMS.
TEMPS ON SUNDAY WILL BE MUCH COOLER WITH AREAS WEST OF I-55 IN THE
UPPER 70S...AND LOW TO MID 80S EXPECTED EAST OF I-55. TEMPS REBOUND
SLIGHTLY ON MONDAY WITH HIGHS IN THE LOW TO MID 80S.
EXTENDED...TUESDAY THROUGH FRIDAY...
HIGH PRESSURE MOVES IN BEHIND THE COLD FRONT LEADING TO ANOTHER
EXTENDED PERIOD OF DRY WEATHER. TEMPS INCREASE THROUGHOUT THE
EXTENDED...AND COULD BE EVEN WARMER THAN FORECAST. EXPECTING UPPER
80S TO QUITE POSSIBLY 90S BY LATE NEXT WEEK.
JEE
&&
.FIRE WEATHER...
428 PM CDT
RH VALUES DROPPED INTO THE 20 PERCENT RANGE ACROSS PARTS OF THE
AREA TODAY...AND SIMILAR CONDITIONS ARE EXPECTED TOMORROW.
TEMPERATURES TOMORROW WILL ONCE AGAIN BE IN THE LOW TO MID
90S...WITH LOWER DEW POINTS THAN TODAY. AMPLE MIXING WILL LIKELY
LEAD TO DEW POINTS DROPPING INTO THE LOW 50S SATURDAY AFTERNOON.
MIN RH VALUES WILL BE IN THE LOW TO MID 20 PERCENT RANGE...HOWEVER
WIND SPEEDS WILL BE AROUND 10 MPH. WIND GUSTS WILL DEVELOP IN THE
AFTERNOON WITH GUSTS UP TO 20 MPH EXPECTED WEST OF I-39...AND
GUSTS AROUND 15 MPH EXPECTED EAST OF I-39. FUEL MOISTURE LEVELS
ARE ABOVE 10 PERCENT FOR MUCH OF NORTHERN ILLINOIS...WHILE AREAS
EAST OF I-55 HAVE 10-HOUR FUELS LESS THAN 10 PERCENT. THEREFORE
TWO OF THE THREE RED FLAG CONDITIONS MAY BE MET IN ISOLATED
LOCATIONS...SIMILAR TO TODAY...BUT NOT EXPECTING ALL THREE RED
FLAG CONDITIONS TO BE MET. THEREFORE NO FIRE WEATHER HEADLINES ARE
ANTICIPATED.
A COLD FRONT MOVES THROUGH THE REGION LATE SATURDAY NIGHT INTO
SUNDAY BRINGING A WIDESPREAD SOAKING RAIN AND COOLER TEMPERATURES
WITH IT.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SPORADIC GUSTS TO 15 KT THIS AFTERNOON.
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE WILL REMAIN IN CONTROL TO THE EAST OF THE REGION
TODAY WITH LOW PRESSURE BECOMING BETTER ORGANIZED ACROSS THE
CENTRAL PLAINS. WITH SUCH A PATTERN...SOUTHERLY WINDS WILL PREVAIL
AND SHOULD BE AT A SIMILAR MAGNITUDE TO THOSE SEEN ON FRIDAY. A
FEW HIGH BASED CU ARE POSSIBLE...AND ANY LAKE BREEZE IS
ANTICIPATED TO REMAIN TO THE EAST OF ORD AND MDW. AS THE LOW
PRESSURE TROUGH INCHES EAST TONIGHT...UPPER LEVEL CLOUDS WILL BE
ON THE INCREASE. THESE CLOUDS WILL LOWER ON SUNDAY WITH RAIN
LIKELY BY AFTERNOON INTO THE EVENING...WITH POTENTIALLY MVFR BASES
DEVELOPING.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE ON ALL FORECAST ELEMENTS.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE TSRA DURING A.M. THEN LIKELY DURING P.M.
PREVAILING VFR BUT LOCAL MVFR OR IFR WITH ANY TS.
MONDAY...SLIGHT CHANCE TSRA DURING A.M. OTHERWISE VFR THROUGH
THE DAY.
TUESDAY TROUGH THURSDAY...VFR. WX NIL.
MTF/TRS
&&
.MARINE...
219 PM CDT
PATTERN REMAINS LARGELY UNCHANGED TODAY AND WILL CONTINUE TO PERSIST
THROUGH MUCH OF THE WEEKEND AS HIGH PRESSURE REMAINS ANCHORED OVER
THE EASTERN STATES AND LOW PRESSURE PERSISTS OVER THE CANADIAN
PRAIRIES. SOUTHERLY FLOW WILL CONTINUE ACROSS LAKE MICHIGAN UNTIL
LATE SUNDAY. THROUGH SUNDAY NIGHT...THE LOW PRESSURE IS FORECAST TO
DEEPEN AS IT LIFTS NORTHEAST TOWARDS HUDSON BAY...AND A TRAILING
COLD FRONT IS EXPECTED TO MOVE ACROSS LAKE MICHIGAN LATE SUNDAY
NIGHT INTO MONDAY TURNING WINDS TO THE WEST OR NORTHWEST. HIGH
PRESSURE WILL THEN BUILD ACROSS THE PLAINS STATES AND MOVE
EAST...BECOMING CENTERED JUST SOUTH OF THE GREAT LAKES REGION. THE
WINDS WILL BE LIGHT OVER THE SOUTHERN HALF OF THE LAKE CLOSE TO THE
HIGH CENTER...BUT THE NORTH HALF OF THE LAKE WILL SEE SLIGHTLY
WINDIER CONDITIONS AS ANOTHER AREA OF LOW PRESSURE DEVELOPS ACROSS
THE CANADIAN PRAIRIES AND A MODEST PRESSURE GRADIENT DEVELOPS OVER
NORTHERN LAKE MICHIGAN. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
955 PM CDT SUN AUG 26 2012
.DISCUSSION...
OUR EVENING POPS AND WEATHER WERE SPLIT FROM 6 TO 3 HOUR
INCREMENTS AND WE HAVE TWEAKED THE REMAINING 03-12 TIME FRAME.
RADAR TRENDS HAVE DIMINISHED COVERAGE FAST OVER THE LAST
HOUR...BUT SOME RE DEVELOPMENT MAY OCCUR. COVERAGE WILL LIKELY
REMAIN SPARSE BUT THE RAP MODEL DOES SHOW SOME POCKETS ON THE
TENTH OF AN INCH CONTOUR FOR QPF THROUGH 12Z. 18Z GFS MUCH THE
SAME. NO CHANGES TO LOWS BUT DEW POINTS HAVE BEEN TRENDED UPWARD
MAY GIVE WAY TO SOME LIGHT FOG...ESPECIALLY WHERE RAIN FELL TODAY.
THE SKY GRIDS WERE ADJUSTED...BUT WILL LIKELY BRING LITTLE OVERALL
TEXT CHANGES. BASICALLY WILL UPDATE ZONES TO REMOVE WORDING FROM
SOME ZONES FOR THE SLIGHT CHANCE DURING THE OVERNIGHT HOURS.
INTERESTINGLY...ON THE WATER VAPOR...OUTFLOW FROM ISSAC IS
WORKING IN CONCERT WITH AN UPPER LOW OVER THE YUCATAN TO PUSH IN
CIRRUS OVER SE LA NOW AND THE MEAGER TROUGH/SHEAR AXIS DRAPED OVER
N TX/OK/AR/MO AND MAY WEAKEN IT/S CONVECTIVE INFLUENCE OVER OUR
AREA FOR TOMORROW UNDER THIS NEW SUBSIDENCE. A PRETTY GOOD DRY
PUSH IN THE MID LEVELS IS SEEN MOVING IN OVER OUR CWA EVEN NOW
AND MAY TAKE AWAY SOME OF OUR 2.02 PWAT SAMPLED ON THE 00Z
SOUNDING. THE GOOD NEWS IS THAT ANOTHER CHECK WILL BE AVAILABLE
WITH THE SPECIAL SOUNDINGS ONGOING. OTHERWISE...WAITING ON THE NEW
RUNS ALONG WITH EVERYBODY ELSE. /24/
.AVIATION...
A FEW SHOWERS STILL LINGER NORTH OF I30 IN NE TEXAS AND SE
OKLAHOMA...BUT THIS ACTIVITY IS DISSIPATING FAST. VFR FLIGHT
CATEGORIES WILL BE COMMON AS WE START THE 06Z TAF PERIOD...WITH A
FEW MID AND HIGH CLOUDS PASSING ACROSS THE AREA. SOME PATCHY FOG MAY
BE OBSERVED BETWEEN 09Z AND 14Z IN THE MORNING...POSSIBLY TAKING
TERMINALS TEMPORARILY DOWN TO IFR CONDITIONS WHERE THIS OCCURS. WE
WILL HANDLE ANY FOG DEVELOPMENT WITH AMD. ALSO MORE SCATTERED
SHRA/TSRA ACTIVITY WILL BE POSSIBLE MONDAY MAINLY AFTER 18Z. LOOK
FOR LIGHT AND VARIABLE WINDS TO PERSIST THROUGH THE 06Z PERIOD. /11/
&&
.PREV DISCUSSION... /ISSUED 257 PM CDT SUN AUG 26 2012/
DISCUSSION...
UPPER LVL TROUGH...WEST OF THE I-30 CORRIDOR...PROVIDING FOCUS FOR
SCATTERED RW/ISOLD TSTMS ACROSS WESTERN HALF OF CWA THIS AFTN...SIMILAR
TO YESTERDAY AS FEATURE HAS MOVED VERY LITTLE. SOMEWHAT OF A
REPEAT MAY OCCUR TOMORROW AFTN...DEPENDING ON DEGREE OF EXPANSION
OF UPPER LVL RIDGING INTO CENTRAL PLAINS...WHICH MAY STRETCH THE
TROUGH...ALLOWING IT TO BECOME SQUEEZED INTO NORTHERN STREAM FLOW
AND SHIFT INTO OHIO VALLEY. IF NOT...DRIER AIR WILL WAIT UNTIL
MONDAY NIGHT AND TUESDAY TO FILTER IN FROM NORTH.
MEANWHILE...T.S ISAAC WILL CONTINUE A SLOW WNW TRACK FOR THE TIME
BEING. THE CENTRAL PLAINS RIDGING WITH EVENTUALLY BECOME A MAJOR FACTOR
UPON WHETHER THE STORM CENTER CURVES NORTHWARD AND REACHES THE
AL/EXTREME WESTERN PANHANDLE SHORELINE....OR WHETHER THE STORM
GETS CAUGHT UP IN ANTICYLONIC ROTATION...TAKING A MORE WESTWARD
TRACK OVER OPEN GULF WATERS. ECMWF AND OFFICIAL TRACK GOING WITH
THE FORMER SOLUTION...WHICH WOULD BRING LITTLE IF ANY WX TO THE
CWA...JUST AN INCREASE IN NE WINDS. HOWEVER...GFS...WHICH IS AN
OUTLIER...BRINGS IT MUCH FURTHER WEST. NOTING THIS
UNCERTAINTY...WILL PRUDENTLY LEAVE ISOLD POPS IN FOR LATE WEEK
INTO EARLY WEEKEND TO ACCOUNT FOR POSSIBILITY OF MORE WESTWARD
TRACK BRINGING ADVERSE WX INTO AREA./VII/.
AVIATION...
MOSTLY VFR FLIGHT WEATHER FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING. EXCEPTION WILL BE IN AND AROUND SCATTERED SHOWERS AND
THUNDERSTORMS WHERE BRIEF PERIODS OF IFR CIGS AND VISIBILITY MAY
OCCUR. WIND GUST TO 35 KTS WITH MODERATE TO SEVERE TURBULENCE CAN BE
EXPECTED NEAR THE STRONGER CONVECTION. AFTER 09Z TONIGHT THROUGH 14Z
MONDAY...EXPECT LOCALIZED AREAS OF IFR VISIBILITY BRIEFLY 1 TO 3
MILES IN FOG. /14/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 96 73 96 70 / 10 20 20 10 10
MLU 69 96 70 94 72 / 10 10 20 20 10
DEQ 72 96 71 95 66 / 20 30 20 10 10
TXK 72 95 71 94 69 / 20 20 20 10 10
ELD 70 95 70 95 70 / 10 20 20 10 10
TYR 74 95 73 95 69 / 20 30 20 10 10
GGG 73 95 73 95 70 / 20 20 20 10 10
LFK 73 96 73 95 71 / 10 20 20 20 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
24/11
AREA FORECAST DISCUSSION
NWS GRAY ME
1137 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER NORTHERN NEW ENGLAND AND THEN SHIFT
OFFSHORE THIS WEEKEND. GENERALLY DRY AND SEASONABLY WARM
CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK BEFORE A COLD
FRONT MOVES THROUGH LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1535Z...FOG AND LOW CLOUDS LOOK TO HAVE BROKEN UP IN MOST PLACES
ATTM...AND HAVE LEFT A BKN...BUT TRANSPARENT CI DECK IN THE SRN
HALF OF THE CWA. THIS SHOULD BE THE MAIN FEATURE FOR THE AFTERNOON
IN THE SOUTH. IN THE NORTH...STARTING TO SEE CU DEVELOP ON THE
TERRAIN...AS SOME INSTABILITY IS GENERATED. THIS TREND WILL
CONTINUE THRU THIS AFTERNOON...AND COMBINED WITH REMNANTS OF SFC
FRONTAL THATS BEEN SITTING OVER THE AREA ALL WEEK...EXPECT TO SEE
A FEW ISOLATED SHRA/TSRA DEVELOP THIS AFTERNOON.
MADE SOME MCHANGES...BASED ON CURRENT CONDS...TO
T/TD/SKY/POP...AND HAVE SENT OUT A FRESH SUITE OF TEXT PRODUCTS
FOR THIS AFTERNOON.
PREV DISC...
A COUPLE CHALLENGES TO THE FCST ONCE AGAIN THIS MORNING.
AFTER MORNING FOG MIXES OUT...HIGH CLOUDS WITH A FEW EMBEDDED AC
WILL CONTINUE TO RIDE INTO THE RIDGE POSITIONED OVER NEW ENGLAND
AND OFF THE EASTERN SEABOARD. THIS MAY LIMIT TEMPS OVER SOUTHERN
ME/NH BY A FEW DEGS DURING THE AFTN HOURS. OTHERWISE...PARTLY TO
MOSTLY SUNNY CONDITIONS WILL PREVAIL NORTH OF THIS REGION THIS
MORNING.
DURING THE AFTN...SUFFICIENT ENOUGH INSTABILITY WILL ALLOW FOR A
SMALL CHANCE FOR A BRIEF SHOWER OVER WRN NH AND THE WRN MTNS OF
MAINE IN THE PROXIMITY AROUND THE PERIPHERY OF THE SURFACE RIDGE.
WITH LI VALUES DROPPING IN THIS AREA AND AMPLE SFC HEATING...THERE
IS ALSO A RISK OF A TSTM IN THIS REGION. LATEST HRRR MODEL CONTS
TO PICK UP ON THIS WIDELY SCT AFTN PCPN.
USED A BLEND OF MAV/MET MOS FOR AFTN MAX TEMPS. AFTN SEA BREEZES
WILL KEEP THE COASTLINE COOLER ONCE AGAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
MORE PATCHY FOG WILL DEVELOP TONIGHT...DESPITE MORE HIGH THIN
CLOUDINESS CROSSING OVER SRN ME/NH. ONCE AGAIN...SOME MID AND
UPPER 40S PSBL FOR OVERNIGHT LOWS IN THE MTNS.
A REPEAT PERFORMANCE OCCURS ON SUNDAY. STILL THE POSSIBILITY
EXISTS FOR A BRIEF SHOWER OR TSTM OVER NH AND THE WRN MTNS OF ME.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE LARGE BROAD SURFACE AND UPPER RIDGE WILL MOVE OFF THE COAST
AND ALLOW A RETURN SSWLY FLOW EARLY NEXT WEEK. TEMPS WILL BE MILD
AND DEWPOINTS WILL BE ON THE RISE EARLY NEXT WEEK WITH CONDITIONS
POSSIBLY BECOMING RATHER MUGGY. BY LATE MON AND TUE THE UPPER
RIDGE BREAKS DOWN ALLOWING AN UPPER TROF TO APPROACH THE AREA FROM
THE WEST SETTING OFF SHWRS/TSTMS LATE MON AND MON NIGHT WITH SCT
SHWRS TUES. A SFC CDFNT ASSOC WITH THE UPPER TROF WILL MOVE THRU
BY LATE TUES OR EARLY WED BRINGING WITH IT A MUCH DRIER CANADIAN
AMS AND COOLER TEMPS FOR THE MID TO LATTER PART OF THE WEEK.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR CONDITIONS WILL PREVAIL ACROSS THE REGION
THROUGHOUT THE PERIOD. SOME VALLEY FOG MAY DEVELOP TONIGHT OVER
FAVORED LOCATIONS RESULTING IN A FEW HOURS OF IFR/LIFR CONDITIONS
BEFORE BURNING OFF EARLY TOMORROW MORNING.
LONG TERM...GENERALLY VFR EXCEPT SHOWERS AND THUNDERSTORMS
POSSIBLE MONDAY AFTERNOON AND MONDAY NIGHT ALLOWING MVFR CONDS TO
DEVELOP...THEN A CHC OF SHWRS TUESDAY.
&&
.MARINE...
SHORT TERM...NO FLAGS EXPECTED
LONG TERM...GENERALLY LIGHT FLOW OVER THE WATERS CONTINUES. COLD
FRONT MOVES THROUGH TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS GRAY ME
915 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER NORTHERN NEW ENGLAND AND THEN SHIFT
OFFSHORE THIS WEEKEND. GENERALLY DRY AND SEASONABLY WARM
CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK BEFORE A COLD
FRONT MOVES THROUGH LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1310Z...DENSE FOG ADV HAS EXPIRED...AND WHILE PATCHY FOG WILL
LINGER THRU MID-MORNING IN SOME SPOTS...VISBYS HAVE COME UP IN
MANY SPOTS. STILL...GIVEN A LACK OF FLOW IN THE LOWEST FEW
THOUSAND FEET...FOG COULD LINGER INTO LATE MORNING THE SHELTERED
SPOTS.
HAVE ALSO REWORKED POPS A BIT FOR THIS AFTERNOON...MAINLY TO SCALE
THEM BACK A BIT...AS THEY LOOK TO BE FORCED...MOSTLY...BY
TERRAIN. THEREFORE WENT WITH COVERAGE TERMINIOLOGY...AND SCALED
BACK TO MORE ISOLATED CONVECTIVE SHRA IN MANY SPOTS.
PREV DISC...
A COUPLE CHALLENGES TO THE FCST ONCE AGAIN THIS MORNING.
AFTER MORNING FOG MIXES OUT...HIGH CLOUDS WITH A FEW EMBEDDED AC
WILL CONTINUE TO RIDE INTO THE RIDGE POSITIONED OVER NEW ENGLAND
AND OFF THE EASTERN SEABOARD. THIS MAY LIMIT TEMPS OVER SOUTHERN
ME/NH BY A FEW DEGS DURING THE AFTN HOURS. OTHERWISE...PARTLY TO
MOSTLY SUNNY CONDITIONS WILL PREVAIL NORTH OF THIS REGION THIS
MORNING.
DURING THE AFTN...SUFFICIENT ENOUGH INSTABILITY WILL ALLOW FOR A
SMALL CHANCE FOR A BRIEF SHOWER OVER WRN NH AND THE WRN MTNS OF
MAINE IN THE PROXIMITY AROUND THE PERIPHERY OF THE SURFACE RIDGE.
WITH LI VALUES DROPPING IN THIS AREA AND AMPLE SFC HEATING...THERE
IS ALSO A RISK OF A TSTM IN THIS REGION. LATEST HRRR MODEL CONTS
TO PICK UP ON THIS WIDELY SCT AFTN PCPN.
USED A BLEND OF MAV/MET MOS FOR AFTN MAX TEMPS. AFTN SEA BREEZES
WILL KEEP THE COASTLINE COOLER ONCE AGAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
MORE PATCHY FOG WILL DEVELOP TONIGHT...DESPITE MORE HIGH THIN
CLOUDINESS CROSSING OVER SRN ME/NH. ONCE AGAIN...SOME MID AND
UPPER 40S PSBL FOR OVERNIGHT LOWS IN THE MTNS.
A REPEAT PERFORMANCE OCCURS ON SUNDAY. STILL THE POSSIBILITY
EXISTS FOR A BRIEF SHOWER OR TSTM OVER NH AND THE WRN MTNS OF ME.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE LARGE BROAD SURFACE AND UPPER RIDGE WILL MOVE OFF THE COAST
AND ALLOW A RETURN SSWLY FLOW EARLY NEXT WEEK. TEMPS WILL BE MILD
AND DEWPOINTS WILL BE ON THE RISE EARLY NEXT WEEK WITH CONDITIONS
POSSIBLY BECOMING RATHER MUGGY. BY LATE MON AND TUE THE UPPER
RIDGE BREAKS DOWN ALLOWING AN UPPER TROF TO APPROACH THE AREA FROM
THE WEST SETTING OFF SHWRS/TSTMS LATE MON AND MON NIGHT WITH SCT
SHWRS TUES. A SFC CDFNT ASSOC WITH THE UPPER TROF WILL MOVE THRU
BY LATE TUES OR EARLY WED BRINGING WITH IT A MUCH DRIER CANADIAN
AMS AND COOLER TEMPS FOR THE MID TO LATTER PART OF THE WEEK.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR CONDITIONS WILL PREVAIL ACROSS THE REGION
THROUGHOUT THE PERIOD. SOME VALLEY FOG MAY DEVELOP TONIGHT OVER
FAVORED LOCATIONS RESULTING IN A FEW HOURS OF IFR/LIFR CONDITIONS
BEFORE BURNING OFF EARLY TOMORROW MORNING.
LONG TERM...GENERALLY VFR EXCEPT SHOWERS AND THUNDERSTORMS
POSSIBLE MONDAY AFTERNOON AND MONDAY NIGHT ALLOWING MVFR CONDS TO
DEVELOP...THEN A CHC OF SHWRS TUESDAY.
&&
.MARINE...
SHORT TERM...NO FLAGS EXPECTED
LONG TERM...GENERALLY LIGHT FLOW OVER THE WATERS CONTINUES. COLD
FRONT MOVES THROUGH TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS GRAY ME
735 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER NORTHERN NEW ENGLAND AND THEN SHIFT
OFFSHORE THIS WEEKEND. GENERALLY DRY AND SEASONABLY WARM
CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK BEFORE A COLD
FRONT MOVES THROUGH LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
LATEST UPDATE IS FOR A DENSE FOG ADVISORY...GOOD THROUGH 9 AM.
THIS IS FOR SOUTHWEST MAINE AND EASTERN NEW HAMPSHIRE.
UPDATING THE GRIDS THIS MORNING TO EXPAND AREAS OF FOG ACROSS THE
REGION. SEVERAL AREAS HAVE FLIRTED WITH THE 1/4 MILE DENSE FOG
ADVISORY CRITERIA...BUT THIS HAS BEEN RELATIVELY BRIEF IN MOST
REGIONS. MAY ISSUE AN SPS TO ACCOUNT FOR ISOLD REGIONS OF DENSE
FOG FOR EARLY MORNING TRAVEL.
WILL STILL HAVE QUITE A FEW CLOUDS OVER SOUTHERN AREAS AFTER THE
MORNING FOG MIXES OUT. THIS IS REFLECTED CURRENTLY IN THE CLOUD
GRIDS. TEMPS MAY RUN A TAD COOLER THAN MOS OVER SOUTHERN LOCATIONS
DUE TO THE BKN...ALBIET HIGH CLOUD COVER.
PREV DISC...
A COUPLE CHALLENGES TO THE FCST ONCE AGAIN THIS MORNING.
AFTER MORNING FOG MIXES OUT...HIGH CLOUDS WITH A FEW EMBEDDED AC
WILL CONTINUE TO RIDE INTO THE RIDGE POSITIONED OVER NEW ENGLAND
AND OFF THE EASTERN SEABOARD. THIS MAY LIMIT TEMPS OVER SOUTHERN
ME/NH BY A FEW DEGS DURING THE AFTN HOURS. OTHERWISE...PARTLY TO
MOSTLY SUNNY CONDITIONS WILL PREVAIL NORTH OF THIS REGION THIS
MORNING.
DURING THE AFTN...SUFFICIENT ENOUGH INSTABILITY WILL ALLOW FOR A
SMALL CHANCE FOR A BRIEF SHOWER OVER WRN NH AND THE WRN MTNS OF
MAINE IN THE PROXIMITY AROUND THE PERIPHERY OF THE SURFACE RIDGE.
WITH LI VALUES DROPPING IN THIS AREA AND AMPLE SFC HEATING...THERE
IS ALSO A RISK OF A TSTM IN THIS REGION. LATEST HRRR MODEL CONTS
TO PICK UP ON THIS WIDELY SCT AFTN PCPN.
USED A BLEND OF MAV/MET MOS FOR AFTN MAX TEMPS. AFTN SEA BREEZES
WILL KEEP THE COASTLINE COOLER ONCE AGAIN.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
MORE PATCHY FOG WILL DEVELOP TONIGHT...DESPITE MORE HIGH THIN
CLOUDINESS CROSSING OVER SRN ME/NH. ONCE AGAIN...SOME MID AND
UPPER 40S PSBL FOR OVERNIGHT LOWS IN THE MTNS.
A REPEAT PERFORMANCE OCCURS ON SUNDAY. STILL THE POSSIBILITY
EXISTS FOR A BRIEF SHOWER OR TSTM OVER NH AND THE WRN MTNS OF ME.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE LARGE BROAD SURFACE AND UPPER RIDGE WILL MOVE OFF THE COAST
AND ALLOW A RETURN SSWLY FLOW EARLY NEXT WEEK. TEMPS WILL BE MILD
AND DEWPOINTS WILL BE ON THE RISE EARLY NEXT WEEK WITH CONDITIONS
POSSIBLY BECOMING RATHER MUGGY. BY LATE MON AND TUE THE UPPER
RIDGE BREAKS DOWN ALLOWING AN UPPER TROF TO APPROACH THE AREA FROM
THE WEST SETTING OFF SHWRS/TSTMS LATE MON AND MON NIGHT WITH SCT
SHWRS TUES. A SFC CDFNT ASSOC WITH THE UPPER TROF WILL MOVE THRU
BY LATE TUES OR EARLY WED BRINGING WITH IT A MUCH DRIER CANADIAN
AMS AND COOLER TEMPS FOR THE MID TO LATTER PART OF THE WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR CONDITIONS WILL PREVAIL ACROSS THE REGION
THROUGHOUT THE PERIOD. SOME VALLEY FOG MAY DEVELOP TONIGHT OVER
FAVORED LOCATIONS RESULTING IN A FEW HOURS OF IFR/LIFR CONDITIONS
BEFORE BURNING OFF EARLY TOMORROW MORNING.
LONG TERM...GENERALLY VFR EXCEPT SHOWERS AND THUNDERSTORMS
POSSIBLE MONDAY AFTERNOON AND MONDAY NIGHT ALLOWING MVFR CONDS TO
DEVELOP...THEN A CHC OF SHWRS TUESDAY.
&&
.MARINE...
SHORT TERM...NO FLAGS EXPECTED
LONG TERM...GENERALLY LIGHT FLOW OVER THE WATERS CONTINUES. COLD
FRONT MOVES THROUGH TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MEZ012-
018>021-023>026.
NH...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NHZ004-006-
010-013-014.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
612 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER NORTHERN NEW ENGLAND AND THEN SHIFT
OFFSHORE THIS WEEKEND. GENERALLY DRY AND SEASONABLY WARM
CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK BEFORE A COLD
FRONT MOVES THROUGH LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
UPDATING THE GRIDS THIS MORNING TO EXPAND AREAS OF FOG ACROSS THE
REGION. SEVERAL AREAS HAVE FLIRTED WITH THE 1/4 MILE DENSE FOG
ADVISORY CRITERIA...BUT THIS HAS BEEN RELATIVELY BRIEF IN MOST
REGIONS. MAY ISSUE AN SPS TO ACCOUNT FOR ISOLD REGIONS OF DENSE
FOG FOR EARLY MORNING TRAVEL.
WILL STILL HAVE QUITE A FEW CLOUDS OVER SOUTHERN AREAS AFTER THE
MORNING FOG MIXES OUT. THIS IS REFLECTED CURRENTLY IN THE CLOUD
GRIDS. TEMPS MAY RUN A TAD COOLER THAN MOS OVER SOUTHERN LOCATIONS
DUE TO THE BKN...ALBIET HIGH CLOUD COVER.
PREV DISC...
A COUPLE CHALLENGES TO THE FCST ONCE AGAIN THIS MORNING.
AFTER MORNING FOG MIXES OUT...HIGH CLOUDS WITH A FEW EMBEDDED AC
WILL CONTINUE TO RIDE INTO THE RIDGE POSITIONED OVER NEW ENGLAND
AND OFF THE EASTERN SEABOARD. THIS MAY LIMIT TEMPS OVER SOUTHERN
ME/NH BY A FEW DEGS DURING THE AFTN HOURS. OTHERWISE...PARTLY TO
MOSTLY SUNNY CONDITIONS WILL PREVAIL NORTH OF THIS REGION THIS
MORNING.
DURING THE AFTN...SUFFICIENT ENOUGH INSTABILITY WILL ALLOW FOR A
SMALL CHANCE FOR A BRIEF SHOWER OVER WRN NH AND THE WRN MTNS OF
MAINE IN THE PROXIMITY AROUND THE PERIPHERY OF THE SURFACE RIDGE.
WITH LI VALUES DROPPING IN THIS AREA AND AMPLE SFC HEATING...THERE
IS ALSO A RISK OF A TSTM IN THIS REGION. LATEST HRRR MODEL CONTS
TO PICK UP ON THIS WIDELY SCT AFTN PCPN.
USED A BLEND OF MAV/MET MOS FOR AFTN MAX TEMPS. AFTN SEA BREEZES
WILL KEEP THE COASTLINE COOLER ONCE AGAIN.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
MORE PATCHY FOG WILL DEVELOP TONIGHT...DESPITE MORE HIGH THIN
CLOUDINESS CROSSING OVER SRN ME/NH. ONCE AGAIN...SOME MID AND
UPPER 40S PSBL FOR OVERNIGHT LOWS IN THE MTNS.
A REPEAT PERFORMANCE OCCURS ON SUNDAY. STILL THE POSSIBILITY
EXISTS FOR A BRIEF SHOWER OR TSTM OVER NH AND THE WRN MTNS OF ME.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE LARGE BROAD SURFACE AND UPPER RIDGE WILL MOVE OFF THE COAST
AND ALLOW A RETURN SSWLY FLOW EARLY NEXT WEEK. TEMPS WILL BE MILD
AND DEWPOINTS WILL BE ON THE RISE EARLY NEXT WEEK WITH CONDITIONS
POSSIBLY BECOMING RATHER MUGGY. BY LATE MON AND TUE THE UPPER
RIDGE BREAKS DOWN ALLOWING AN UPPER TROF TO APPROACH THE AREA FROM
THE WEST SETTING OFF SHWRS/TSTMS LATE MON AND MON NIGHT WITH SCT
SHWRS TUES. A SFC CDFNT ASSOC WITH THE UPPER TROF WILL MOVE THRU
BY LATE TUES OR EARLY WED BRINGING WITH IT A MUCH DRIER CANADIAN
AMS AND COOLER TEMPS FOR THE MID TO LATTER PART OF THE WEEK.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR CONDITIONS WILL PREVAIL ACROSS THE REGION
THROUGHOUT THE PERIOD. SOME VALLEY FOG MAY DEVELOP TONIGHT OVER
FAVORED LOCATIONS RESULTING IN A FEW HOURS OF IFR/LIFR CONDITIONS
BEFORE BURNING OFF EARLY TOMORROW MORNING.
LONG TERM...GENERALLY VFR EXCEPT SHOWERS AND THUNDERSTORMS
POSSIBLE MONDAY AFTERNOON AND MONDAY NIGHT ALLOWING MVFR CONDS TO
DEVELOP...THEN A CHC OF SHWRS TUESDAY.
&&
.MARINE...
SHORT TERM...NO FLAGS EXPECTED
LONG TERM...GENERALLY LIGHT FLOW OVER THE WATERS CONTINUES. COLD
FRONT MOVES THROUGH TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
231 AM EDT SAT AUG 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER NORTHERN NEW ENGLAND AND THEN SHIFT
OFFSHORE THIS WEEKEND. GENERALLY DRY AND SEASONABLY WARM
CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK BEFORE A COLD
FRONT MOVES THROUGH LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
A COUPLE CHALLENGES TO THE FCST ONCE AGAIN THIS MORNING. AFTER
MORNING FOG MIXES OUT...HIGH CLOUDS WITH A FEW EMBEDDED AC WILL
CONTINUE TO RIDE INTO THE RIDGE POSITIONED OVER NEW ENGLAND AND
OFF THE EASTERN SEABOARD. THIS MAY LIMIT TEMPS OVER SOUTHERN ME/NH
BY A FEW DEGS DURING THE AFTN HOURS. OTHERWISE...PARTLY TO MOSTLY
SUNNY CONDITIONS WILL PREVAIL NORTH OF THIS REGION THIS MORNING.
DURING THE AFTN...SUFFICIENT ENOUGH INSTABILITY WILL ALLOW FOR A
SMALL CHANCE FOR A BRIEF SHOWER OVER WRN NH AND THE WRN MTNS OF
MAINE IN THE PROXIMITY AROUND THE PERIPHERY OF THE SURFACE RIDGE.
WITH LI VALUES DROPPING IN THIS AREA AND AMPLE SFC HEATING...THERE
IS ALSO A RISK OF A TSTM IN THIS REGION. LATEST HRRR MODEL CONTS
TO PICK UP ON THIS WIDELY SCT AFTN PCPN.
USED A BLEND OF MAV/MET MOS FOR AFTN MAX TEMPS. AFTN SEA BREEZES
WILL KEEP THE COASTLINE COOLER ONCE AGAIN.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
MORE PATCHY FOG WILL DEVELOP TONIGHT...DESPITE MORE HIGH THIN
CLOUDINESS CROSSING OVER SRN ME/NH. ONCE AGAIN...SOME MID AND
UPPER 40S PSBL FOR OVERNIGHT LOWS IN THE MTNS.
A REPEAT PERFORMANCE OCCURS ON SUNDAY. STILL THE POSSIBILITY
EXISTS FOR A BRIEF SHOWER OR TSTM OVER NH AND THE WRN MTNS OF ME.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE LARGE BROAD SURFACE AND UPPER RIDGE WILL MOVE OFF THE COAST
AND ALLOW A RETURN SSWLY FLOW EARLY NEXT WEEK. TEMPS WILL BE MILD
AND DEWPOINTS WILL BE ON THE RISE EARLY NEXT WEEK WITH CONDITIONS
POSSIBLY BECOMING RATHER MUGGY. BY LATE MON AND TUE THE UPPER
RIDGE BREAKS DOWN ALLOWING AN UPPER TROF TO APPROACH THE AREA FROM
THE WEST SETTING OFF SHWRS/TSTMS LATE MON AND MON NIGHT WITH SCT
SHWRS TUES. A SFC CDFNT ASSOC WITH THE UPPER TROF WILL MOVE THRU
BY LATE TUES OR EARLY WED BRINGING WITH IT A MUCH DRIER CANADIAN
AMS AND COOLER TEMPS FOR THE MID TO LATTER PART OF THE WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR CONDITIONS WILL PREVAIL ACROSS THE REGION
THROUGHOUT THE PERIOD. SOME VALLEY FOG MAY DEVELOP TONIGHT OVER
FAVORED LOCATIONS RESULTING IN A FEW HOURS OF IFR/LIFR CONDITIONS
BEFORE BURNING OFF EARLY TOMORROW MORNING.
LONG TERM...GENERALLY VFR EXCEPT SHOWERS AND THUNDERSTORMS
POSSIBLE MONDAY AFTERNOON AND MONDAY NIGHT ALLOWING MVFR CONDS TO
DEVELOP...THEN A CHC OF SHWRS TUESDAY.
&&
.MARINE...
SHORT TERM...NO FLAGS EXPECTED
LONG TERM...GENERALLY LIGHT FLOW OVER THE WATERS CONTINUES. COLD
FRONT MOVES THROUGH TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
254 PM EDT SAT AUG 25 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM LIFTS NORTH ACROSS SOUTHERN VIRGINIA THIS
AFTERNOON..AS HIGH PRESSURE REMAINS ANCHORED OVER NEW ENGLAND.
THIS AREA OF LOW PRESSURE WILL DISSIPATE SUNDAY OVER THE CENTRAL
APPALACHIANS AS HIGH PRESSURE RETURNS TO THE REGION EARLY NEXT
WEEK. A COLD FRONT WILL APPROACH THE REGION BY MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A VERY WET MRNG FOR MANY AREAS OF FA. WK SFC LO PRES LIFING INTO
XTRM SCNTRL VA RIGHT NOW WILL BE SLO TO CONT TO TRACK NNW THIS
AFTN. SVRL BANDS OF MOD/HVY RA ASSOCIATED W/ TSTMS MOVG INTO ERN
VA AND TWD THE CAPITAL CITY. SVRL LOCATIONS IN SE/SCNTRL VA AND
FAR INTR NE NC HAVE RECEIVED 3-6 IN OF RA...INCLDG HERE AT THE
OFFICE. TRIMMED POPS FOR SE PORTION OF FA AS DRIER AIR MOVG N
INVOF CST...HIGHEST POPS (60-80%) INTO MID AFTN FOR THE FAR W AND
ACRS NRN 1/3RD OF FA. 14Z/25 RUC SUGGESTS HEAVIEST RA WILL BCM
CONCENTRATED IN AREAS FM RIC ON E AND NE THROUGH 18Z/25.
HI TEMPS L/M80S SE...TO M70S NNW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
THE MID-LEVEL WAVE STEADILY DISSIPATES TONIGHT THROUGH SUNDAY OVER
THE CENTRAL APPALACHIANS...WITH SHORTWAVE RIDGING PREVAILING BY
MONDAY AHEAD OF A COLD FRONT OVER THE OHIO VALLEY AND ISAAC WELL TO
THE SOUTH NEAR THE GULF COAST. THE CHANCE OF SHOWERS DIMINISHES AS
WELL ALONG WITH AT LEAST A PARTIAL CLEARING TREND. HIGH TEMPERATURES
SHOULD REACH THE MID TO UPPER 80S SUNDAY FOLLOWED BY UPPER 80S TO
AROUND 90 MONDAY. LOW TEMPERATURES SHOULD BE IN THE MID TO UPPER 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
PLEASE FOLLOW THE LATEST FCST FROM THE NHC FOR DETAILS ON TS ISAAC.
LATEST FCST FOR ISAAC CONTINUES TO FAVOR A TRACK INTO THE GULF OF
MEXICO AND GENLY WELL TO THE SW OF THE AKQ CWA. ANY REMNANTS OF
ISAAC WOULD NOT APPEAR TO AFFECT THE LOCAL AREA UNTIL TUE NGT/WED AT
THE EARLIEST...WITH THE MAIN POTENTIAL IMPACT BEING HEAVY RAIN.
MID-LVL S/W TROF AND ASSOCIATED FRONTAL BNDRY APPROACH FROM THE WEST
ON TUE LEADING TO A CHC FOR RAIN. MAIN ISSUE DURING THE WEEK IS HOW
STRONG THE TROF OVER THE EASTERN CONUS WILL BE...WILL IT BE
AMPLIFIED ENUF TO PICK UP ISAAC AND ADVANCE IT TOWARDS THE MID
ATLANTIC (12Z GFS SOLUTION)...OR WILL THE TROF BE WEAKER AND MORE
PROGRESSIVE...LEADING TO ISAAC MISSING THE TROF AND INSTEAD HEADING
IN A N/NW DIRECTION FOLLOWING LANDFALL (12Z ECMWF SOLUTION)...WHICH
MEANS SFC HI PRES AND MAINLY DRY CONDITIONS OVER THE MID ATLANTIC
THROUGH NEXT FRI. WILL CONTINUE A BLENDED FORECAST DUE TO THE LARGE
UNCERTAINTY WITH A BIT MORE WEIGHT PUT ON THE ECMWF...NO HIGHER THAN
30-40% POPS THRU THE PERIOD AND HIGH TEMPS RANGING THRU THE 80S OVER
THE COURSE OF THE WEEK.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
PLENTY OF LOW LEVEL MOISTURE WILL RESULT IN MARGINAL VFR CEILINGS
THROUGH MOST OF THE TAF PERIOD. SOME IFR PSBL ESPECIALLY AT PHF
WHERE SEVERAL INCHES OF RAIN FELL EARLY SATURDAY. AREAS OF RAIN AND
TSTMS WILL SHIFT TO THE NORTH THROUGH SATURDAY EVENING. WINDS WILL
BE GENERALLY FROM THE SOUTHEAST AS SURFACE LOW STALLS OVER SOUTHERN
VIRGINIA. CONDITIONS SLOWLY IMPROVES BY MIDDAY SUNDAY.
OUTLOOK...MAINLY DRY WEATHER IS FORECAST SUNDAY AND MONDAY. THERE
WILL BE CHANCE FOR MAINLY AFTN TSTMS BEGINNING TUESDAY. SOME MORNING
MVFR/IFR WILL BE PSBL DURING THE OUTLOOK PERIOD.
&&
.MARINE...
HIGH RISK OF RIP CURRENTS IN EFFECT FOR TODAY WITH STRONG ONSHORE
FLOW AND HIGH SWELL PERIOD EXPECTED.
MAINTAINED SCA`S THRU THIS AFTN/EVENG FOR THE CHES BAY AND THE
LWR JAMES RIVER NEAR HAMPTON ROADS BRIDGE TUNNEL...AND THRU THIS
AFTN OR THRU LATE TNGT FOR THE CSTL WTRS...DUE TO STRNG NE OR E
WNDS CAUSED BY PRESSURE GRADIENT BETWEEN HI PRES JUST OFF THE NEW
ENGLAND CST AND LO PRES MOVNG NWRD FM JUST OFF THE NC CST. WAVES
OVR THE CHES BAY WILL BLD TO 3-5 FT WITH SEAS OVR THE COASTAL
WTRS BLDNG TO 5-6 FT. AFOREMENTIONED LO PRES WEAKENS AND
DISSIPATES OVR VA SUN MORNG. A LOT OF UNCERTAINTY STILL WITH THE
EVENTUAL TRACK OF TS ISAAC (SEE LATEST NHC FCST FOR DETAILS).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ632-
634.
SMALL CRAFT ADVISORY UNTIL 1 AM EDT SUNDAY FOR ANZ630-631.
SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ638-
656-658.
SMALL CRAFT ADVISORY UNTIL 1 PM EDT SUNDAY FOR ANZ650-652-654.
&&
$$
SYNOPSIS...AJZ/ALB/SAM
NEAR TERM...AJZ/ALB
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...LSA
MARINE...TMG
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1112 AM EDT SAT AUG 25 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM LIFTS NORTH ACROSS SOUTHERN VIRGINIA THIS
AFTERNOON..AS HIGH PRESSURE REMAINS ANCHORED OVER NEW ENGLAND.
THIS AREA OF LOW PRESSURE WILL DISSIPATE SUNDAY OVER THE CENTRAL
APPALACHIANS AS HIGH PRESSURE RETURNS TO THE REGION EARLY NEXT
WEEK. A COLD FRONT WILL APPROACH THE REGION BY MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A VERY WET MRNG FOR MANY AREAS OF FA. WK SFC LO PRES LIFING INTO
XTRM SCNTRL VA RIGHT NOW WILL BE SLO TO CONT TO TRACK NNW THIS
AFTN. SVRL BANDS OF MOD/HVY RA ASSOCIATED W/ TSTMS MOVG INTO ERN
VA AND TWD THE CAPITAL CITY. SVRL LOCATIONS IN SE/SCNTRL VA AND
FAR INTR NE NC HAVE RECEIVED 3-6 IN OF RA...INCLDG HERE AT THE
OFFICE. TRIMMED POPS FOR SE PORTION OF FA AS DRIER AIR MOVG N
INVOF CST...HIGHEST POPS (60-80%) INTO MID AFTN FOR THE FAR W AND
ACRS NRN 1/3RD OF FA. 14Z/25 RUC SUGGESTS HEAVIEST RA WILL BCM
CONCENTRATED IN AREAS FM RIC ON E AND NE THROUGH 18Z/25.
HI TEMPS L/M80S SE...TO M70S NNW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
THE MID-LEVEL WAVE STEADILY DISSIPATES TONIGHT THROUGH SUNDAY OVER
THE CENTRAL APPALACHIANS...WITH SHORTWAVE RIDGING PREVAILING BY
MONDAY AHEAD OF A COLD FRONT OVER THE OHIO VALLEY AND ISAAC WELL TO
THE SOUTH NEAR THE GULF COAST. THE CHANCE OF SHOWERS DIMINISHES AS
WELL ALONG WITH AT LEAST A PARTIAL CLEARING TREND. HIGH TEMPERATURES
SHOULD REACH THE MID TO UPPER 80S SUNDAY FOLLOWED BY UPPER 80S TO
AROUND 90 MONDAY. LOW TEMPERATURES SHOULD BE IN THE MID TO UPPER 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
PLEASE FOLLOW THE LATEST FCST FROM THE NHC FOR DETAILS ON TS ISAAC.
LATEST FCST FOR ISAAC CONTINUES TO FAVOR A TRACK INTO THE GULF OF
MEXICO AND GENLY WELL TO THE SW OF THE AKQ CWA. ANY REMNANTS OF
ISAAC WOULD NOT APPEAR TO AFFECT THE LOCAL AREA UNTIL TUE NGT/WED AT
THE EARLIEST...WITH THE MAIN POTENTIAL IMPACT BEING HEAVY RAIN.
MID-LVL S/W TROF AND ASSOCIATED FRONTAL BNDRY APPROACH FROM THE WEST
ON TUE LEADING TO A CHC FOR RAIN. MAIN ISSUE DURING THE WEEK IS HOW
STRONG THE TROF OVER THE EASTERN CONUS WILL BE...WILL IT BE
AMPLIFIED ENUF TO PICK UP ISAAC AND ADVANCE IT TOWARDS THE MID
ATLANTIC (12Z GFS SOLUTION)...OR WILL THE TROF BE WEAKER AND MORE
PROGRESSIVE...LEADING TO ISAAC MISSING THE TROF AND INSTEAD HEADING
IN A N/NW DIRECTION FOLLOWING LANDFALL (12Z ECMWF SOLUTION)...WHICH
MEANS SFC HI PRES AND MAINLY DRY CONDITIONS OVER THE MID ATLANTIC
THROUGH NEXT FRI. WILL CONTINUE A BLENDED FORECAST DUE TO THE LARGE
UNCERTAINTY WITH A BIT MORE WEIGHT PUT ON THE ECMWF...NO HIGHER THAN
30-40% POPS THRU THE PERIOD AND HIGH TEMPS RANGING THRU THE 80S OVER
THE COURSE OF THE WEEK.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
LO PRES JUST OFF THE NC CST WILL MOVE SLOWLY N AND INTO ERN
PORTIONS OF THE AREA TDY INTO SUN MORNG. THIS WILL RESULT IN MVFR
(ISLTD IFR) CONDITIONS WITH SHOWERS ACRS THE AREA. AREAS OF IFR
FOG AND STRATUS WILL BE POSSIBLE SUN AND MON MORNGS...OTHRWISE
EXPECTING MAINLY DRY CONDITIONS FOR SUN AFTN THRU MON.
&&
.MARINE...
HIGH RISK OF RIP CURRENTS IN EFFECT FOR TODAY WITH STRONG ONSHORE
FLOW AND HIGH SWELL PERIOD EXPECTED.
MAINTAINED SCA`S THRU THIS AFTN/EVENG FOR THE CHES BAY AND THE
LWR JAMES RIVER NEAR HAMPTON ROADS BRIDGE TUNNEL...AND THRU THIS
AFTN OR THRU LATE TNGT FOR THE CSTL WTRS...DUE TO STRNG NE OR E
WNDS CAUSED BY PRESSURE GRADIENT BETWEEN HI PRES JUST OFF THE NEW
ENGLAND CST AND LO PRES MOVNG NWRD FM JUST OFF THE NC CST. WAVES
OVR THE CHES BAY WILL BLD TO 3-5 FT WITH SEAS OVR THE COASTAL
WTRS BLDNG TO 5-6 FT. AFOREMENTIONED LO PRES WEAKENS AND
DISSIPATES OVR VA SUN MORNG. A LOT OF UNCERTAINTY STILL WITH THE
EVENTUAL TRACK OF TS ISAAC (SEE LATEST NHC FCST FOR DETAILS).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ632-
634-638-656-658.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ630-
631.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ650-652-654.
&&
$$
SYNOPSIS...AJZ/ALB/SAM
NEAR TERM...AJZ/ALB
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...TMG
MARINE...TMG
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
130 AM EDT SAT AUG 25 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 348 PM EDT FRI AUG 24 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A GENERAL ZONAL
FLOW OVER THE NRN TIER CONUS/SRN CANADA. A SHRTWV EMBEDDED IN THIS
FLOW IS PRESENT OVER WI/UPR MI EARLY THIS AFTN AND HAS BEEN
SUPPORTING SOME ISOLD -SHRA/A FEW TS OVER MAINLY THE E HALF OF THE
CWA DESPITE PRESENCE OF DRY LLVL AIR SHOWN ON THE 12Z GRB/APX RAOBS
THAT EXTENDS WELL TO THE S AS DEPICTED ON THE 12Z RAOB FM QUAD
CITIES IOWA. OVER THE W HALF...NVA IN THE WAKE OF THE SHRTWV AND
AGGRESSIVE DRYING FOCUSED AT H5-7 WITH ENEWD SPREAD OF AIRMASS SHOWN
ON THE 12Z MPX RAOB HAS SUPPRESSED SHRA AND RESULTED IN SOME CLRG IN
DESPITE PERSISTENCE OF AXIS OF HIER H85 DEWPTS/THETA-E IN THAT AREA
PER RUC ANALYSIS. SHRTWV RDG AXIS OVER MN IS BRINGING DRY WX THERE
ALONG WITH MOCLR SKIES...BUT MORE CLDS AND SOME SHRA/TS ARE OVER THE
NRN PLAINS IN ADVANCE OF POTENT SHRTWV MOVING EWD THRU SRN ALBERTA.
LATE THIS AFTN...DESPITE NVA/AGGRESSIVE UPR DRYING IN THE WAKE OF
SLOW MOVING SHRTWV...SUSPECT SOME SHRA/TS MAY DVLP ON THE LEADING
EDGE OF THE H5-7 DRYING WHERE MORE INSOLATION WL COINCIDE WITH AREA
OF HIER H85 DEWPTS. A NUMBER OF THE RECENT HIER RES MODELS SHOW AT
LEAST ISOLD-SCT SHRA/TS DVLPG OVER THE CENTRAL ZNS...SO PAINTED AN
AXIS OF SOMEWHAT HIER CHC POPS IN THIS AREA. THE FAR W SHOULD BE DRY
UNDER MUCH DRIER H7-5 AIR AND WITH SOME MODERATION NEAR LK SUP.
LINGERING LLVL DRY AIR OVER THE E SHOULD ALSO LIMIT POPS IN THAT
AREA DESPITE MORE MID LVL MSTR THAT MIGHT SUPPORT PERSISTENT -SHRA.
TNGT...AS DEEPER SHRTWV OVER SW CANADA THIS MRNG DRIFTS EWD AND
SHRTWV OVER THE AREA SHIFTS TO THE E...ARRIVAL OF SHRTWV RDG FM MN/
ASSOCIATED H5 RISES IN CONCERT WITH LOSS OF DAYTIME HEATING SHOULD
CAUSE ANY EVNG SHRA/TS OVER MAINLY THE E AND CENTRAL ZNS TO
DISSIPATE. PCPN CHCS WL LINGER LONGEST OVER THE E CLOSER TO
DEPARTING SHRTWV/WHERE MID LVL MSTR REMAINS MOST ABUNDANT LONGEST.
ALTHOUGH THERE WAS QUITE A BIT OF FOG LAST NGT OVER MN...THE 12Z
NAM/LOCAL WRF-ARW SHOW PERSISTENT SSW LLVL FLOW DRAWING DRIER AIR
SHOWN ON THE 12Z GRB/QUAD CITY RAOBS INTO THE FA. SO EXPECT NO FOG
TO IMPACT THE CWA. DESPITE THE DRYING COLUMN...STEADY S WIND SHOULD
LIMIT THE DIURNAL TEMP FALL AT MOST SPOTS...FURTHER LIMITING THE
POTENTIAL FOR FOG.
SAT...FOCUS TURNS TO HOW QUICKLY STRONG DISTURBANCE OVER SW CANADA
THIS MRNG MIGHT INFLUENCE THE WX ESPECIALLY OVER THE WRN CWA. THE
DAY SHOULD AT LEAST START MOSUNNY WITH SHRTWV RDG AXIS/DRY H85-5
AIRMASS OVHD. BY 00Z SUN...THE SHRTWV IS PROGGED TO DRIFT NEWD TO
NEAR LK WINNIPEG AND BECOME OCCLUDED WITH H5 CUTOFF NEARLY OVER
992MB SFC LO. SINCE LLVL SLY FLOW IS FCST TO ADVECT THE DRIER
SFC-H85 AIR NOTED TO THE S OVER THE CWA THRU THE DAY AND BULK OF
DEEP LYR QVECTOR CNVGC OVER WARM CONVEYOR BELT MSTR/ATTENDANT SFC
COLD FNT ARE PROGGED TO RACH ONLY THE FAR W BY 00Z SUN...OPTED TO
SLOW DOWN EWD PUSH OF ACCOMPANYING POPS. GIVEN THE STRENGTH OF THE
SHRTWV TO THE W...PREFER THE HIER H85 FCST TEMPS BY THE NAM...WHICH
SHOWS THIS TEMP REACHING 20C OVER THE CWA VERSUS ONLY 17C BY THE
GFS. DEEP MIXING ON THE NAM FCST SDNGS YIELDS HI TEMPS REACHING ARND
90. MAX TEMPS WL BE HIEST NEAR LK SUP WHERE SLY FLOW DOWNSLOPES AND
LIMITS AND MODERATION OFF LK SUP. IN FACT...SOME RECORD HI TEMPS MAY
FALL ON SAT. AREAS DOWNWIND OF LK MI WL BE COOLEST. WITH SFC DEWPTS
LIKELY TO MIX OUT TO ARND 50 AWAY FM LK MODERATION...MIN RH WL DIP
AS LO AS 25 PCT IN THE PRESENCE OF WIND GUSTS TO 20-25 MPH ENHANCED
BY THE MIXING. FORTUNATELY...RECENT RAINS HAVE MOISTENED THE GROUND
SUFFICIENTLY TO MINIMIZE ANY FIRE WX IMPACTS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 348 PM EDT FRI AUG 24 2012
AN UPPER-LEVEL TROUGH AND SLOW-MOVING COLD FRONT WILL CONTINUE TO
BRING RAIN AND THUNDERSTORM CHANCES TO UPPER MI THROUGH MONDAY
BEFORE DRY AND WARMER WEATHER RETURNS UNDER HIGH PRESSURE FOR THE
MIDDLE OF THE WEEK.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...A SHARP TROUGH CURRENTLY
MOVING THROUGH ALBERTA AND NORTHERN MT WILL SHIFT EAST THROUGH
SATURDAY AND INDUCE A STRONG SFC LOW OVER SOUTHERN SASKATCHEWAN. BY
SATURDAY NIGHT...THE TROUGH WILL BE LIFTING TO THE NORTHEAST THROUGH
MANITOBA WHILE BECOMING NEARLY STACKED WITH THE ASSOCIATED SFC LOW.
A COLD FRONT EXTENDING FROM A NEW OCCLUSION OVER WESTERN ONTARIO
WILL BE SURGING EASTWARD THROUGH MN SATURDAY AFTERNOON. THERE IS
VERY GOOD MODEL AGREEMENT THAT THIS COLD FRONT WILL REACH THE
WESTERN TIP OF THE CWA BY 06Z SUNDAY...THEN WASH OUT ACROSS THE
CENTRAL CWA BY SUNDAY AFTERNOON AS IT LOSES SUPPORT FROM THE
WEAKENING STACKED LOW. A SECONDARY SFC TROUGH WILL THEN CATCH UP TO
THE FRONT AND HELP KICK IT OUT OF THE CWA BY SUNDAY EVENING.
NOT TOO CONFIDENT ON WIDESPREAD PRECIP CHANCES ATTM FOR SEVERAL
REASONS. FIRST...BEST Q-VECTOR CONVERGENCE WILL EXIST NORTH CLOSER
TO THE MID-LEVEL LOW...AND SOUTH WHERE A SHORTWAVE TROUGH WILL BE
MOVING INTO THE MID-MS VALLEY FROM THE SOUTHERN PLAINS. NEXT...THE
SFC LOW FORMING IN RESPONSE TO THE SOUTHERN PLAINS TROUGH WILL
LIKELY CUTOFF A SIGNIFICANT PORTION OF THE MOISTURE SUPPLY AHEAD OF
THE FRONT. THUS...APPRECIABLE MOISTURE WILL BE CONFINED TO THE NEAR
SFC LAYER OVER UPPER MI. ANY PRECIP THAT FORMS WILL BE FORCED BY A
BAND OF H8-H7 FRONTOGENESIS ALONG THE FRONT...THOUGH MOISTURE WILL
BE LACKING IN THIS LAYER. CUT BACK POPS TO LOW CHANCE FOR MUCH OF
THE LAND...WITH HIGHER POPS OVER THE WESTERN LAKE AS IT WILL BE
CLOSER TO BETTER FORCING FROM THE LOW. SOME SFC HEATING WILL AID
DEVELOPMENT OF NEW SHOWERS AND THUNDERSTORMS IN THE AFTERNOON ACROSS
THE EAST HALF...BUT ONCE AGAIN...A LACK OF MOISTURE WILL STILL BE A
CONCERN.
INCREASED/DECREASED HIGHS IN THE WEST/EAST FOR SUNDAY TO ACCOUNT FOR
CLOUD AND PRECIP TRENDS. EXPECTATION IS THAT CLOUDS WILL QUICKLY
CLEAR WEST IN THE MORNING. H8 TEMPS WILL COOL TO AROUND 14C WITH
THIS CLEARING...BUT SHOULD STILL BE WARM ENOUGH TO PRODUCE LOW 80S
FOR HIGHS. PATCHY FOG COULD BE POSSIBLE FOR THE INTERIOR WEST SUNDAY
NIGHT...BUT DRY AIR ADVECTING INTO THE AREA SHOULD BE ENOUGH TO
SUBDUE THE THREAT.
MONDAY AND MONDAY NIGHT...AS THE MID-LEVEL LOW DRIFTS NORTHEASTWARD
TO HUDSON BAY SUNDAY NIGHT...IT WILL TAP INTO SOME ENERGY FROM THE
RAGGED POLAR VORTEX OVER NORTHERN NUNAVUT. THE REINFORCED TROUGH AND
WEAK SFC TROUGH ARE THEN PROGGED TO AFFECT THE AREA MONDAY NIGHT.
MODELS BEGIN TO DIVERGE SIGNIFICANTLY BY THIS POINT...BUT VERY
LITTLE MOISTURE ABOVE THE SFC MIXED LAYER WILL LIKELY PREVENT ANY
PRECIP. EVEN MORE...DO NOT EXPECT MUCH CLOUD COVER EXCEPT FOR
POSSIBLE AFTERNOON CUMULUS. HIGHS WILL BE IN THE 70S...WITH THE
COOLEST TEMPS NORTH CLOSER TO A H8 TEMP MIN IN NORTHERN ONTARIO.
TUESDAY THROUGH THURSDAY...A VERY IMPRESSIVE RIDGE WILL SLOWLY EDGE
INTO THE UPPER GREAT LAKES BEGINNING TUESDAY...WITH THE SFC HIGH
PRESSURE CENTERING ITSELF OVER WI/UPPER MI BY WEDNESDAY MORNING. THE
HIGH WILL CONTINUE TO GRADUALLY DRIFT SOUTHEASTWARD WEDNESDAY
THROUGH THURSDAY...WITH UPPER MI REMAINING UNDER ITS INFLUENCE.
INCREASED HIGHS THROUGH FRIDAY AS THERE WILL BE PLENTY OF SUN AND
WARM H8 TEMPS. ISENTROPIC LIFT ON THE 305-310 THEATA SFCS IN
ADDITION TO H8 MOISTURE TRANSPORT MAY RESULT IN A FEW SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT...MAINLY NORTH.
FRIDAY...THERE IS MODEL AGREEMENT THAT THE RIDGE WILL BEGIN TO BREAK
DOWN BY EARLY FRIDAY. THE GFS IS ONCE AGAIN MORE AGGRESSIVE THAN THE
ECMWF WITH A TROUGH FROM BRITISH COLUMBIA MOVING INTO THE RIDGE. IT
IS DIFFICULT TO SAY WHICH MODEL WILL PAN OUT...IF EITHER...SO WILL
GO WITH A MODEL CONSENSUS FOR THE FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 129 AM EDT SAT AUG 25 2012
EXPECT VFR CONDITIONS AT ALL 3 SITES THRU THIS FCST PERIOD WITH
RELATIVELY DRY LLVL AIR IN PLACE. DID PUT IN SOME LLWS IN IWD
OVERNIGHT. NEXT SYSTEM BEGINS TO AFFECT IWD IN THE EVENING WITH PCPN
HOLDING OFF UNTIL REALLY LATE IN THE PERIOD. CONFIDENCE LOW RIGHT
NOW TO PUT IN TIMING OF PCPN AT KIWD AS MOISTURE STILL REMAINS TO
THE WEST OF THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 24 2012
EXCEPT FOR A STRONGER S WIND UP TO 25 KTS OVER THE E INTO THIS
EVENING AHEAD OF AN APPROACHING LO PRES TROF...WINDS THRU THE
FORECAST PERIOD WILL BE NO HIER THAN 20 KTS AS THE COMBINATION OF A
WEAK PRES GRADIENT AND HIER OVERWATER STABILITY LIMIT WIND SPEEDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TK
AVIATION...GM/RJT
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1045 PM CDT SUN AUG 26 2012
.UPDATED FOR 06Z AVIATION...
&&
.DISCUSSION...
STILL ON TRACK FOR SIGNIFICANT UPPER RIDGING TO BUILD IN BY MID
WEEK...WITH H85 TEMPS OF 2 STANDARD DEVIATIONS STILL PEGGED TO BE
OVERHEAD WEDNESDAY AND THURSDAY...WHICH AT THIS POINT LOOK TO BE
THE WARMEST DAYS OF THE NEXT WEEK. PRECIP CHANCES ALSO LOOK
MINIMAL...BUT THERE IS THE POSSIBILITY OF SOME ACTIVITY WITH A
WARM FRONT TUESDAY EVENING/NIGHT AND AGAIN OVER THE WEEKEND WITH A
COOL FRONT.
HIGH PRESSURE IS ON ITS WAY INTO THE AREA TODAY...ALONG WITH
SIGNIFICANT ATMO DRYING...AS EVIDENCED BY PRONOUNCED CLEARING
MOVING SE ON SATELLITE AND TONGUE OF PWATS NEAR 0.5 INCHES ON THE
SPC MESO ANALYSIS DROPPING SOUTHEAST. THIS DRY AIR AND HIGH
PRESSURE WILL RESULT IN GOOD RADIATIONAL COOLING CONDITIONS
TONIGHT...WITH LOWS OUTSIDE OF THE CITIES FALLING BACK INTO THE
50S. WITH PWATS FALLING UNDER AN INCH...THIS SHOULD ALSO LIMIT FOG
POTENTIAL TONIGHT...AND NAM BUFKIT SOUNDINGS CERTAINLY SUPPORT THE
IDEA OF SEEING LIMITED FOG OVERNIGHT.
TEMPS MONDAY WILL ONLY BE 5 OR SO DEGREES ABOVE NORMAL...AS HIGH
PRESSURE CENTERED OVER WI WILL KEEP THE AREA COOLER...THOUGH WILL
HAVE TO WATCH FOR SOME MIXED DEWPOINT POTENTIAL DURING THE
AFTERNOON. TUESDAY...THE WARM FRONT ALONG WITH H85 TEMPS AROUND 2
STANDARD DEVIATIONS ABOVE NORMAL BEGIN TO MAKE AN APPEARANCE THIS
FAR EAST. DURING THE LATE AFTERNOON...THE NAM/GFS SHOW ISENTROPIC
LIFT ON THE 315K SFC INCREASING SUBSTANTIALLY...ALONG WITH SOME
MOISTENING. EVEN SOME MID-LEVEL FGEN INDICATED BY BOTH MODELS IN
CONCERT WITH A 20 TO 30 KT LLJ. LEFT PRECIP OUT AT THIS TIME...BUT
NUMERICAL GUIDANCE TENDS TO DO A POOR JOB WITH THESE TYPES OF
PRECIP SCENARIOS AND WOULD NOT BE SURPRISED IF WE DO END UP WITH
SOME ELEVATED CONVECTION. WITH THE PATH OF ISAAC STILL UP IN THE
AIR...I REALIZE THIS IS NOT ALL THAT EXCITING...BUT ITS THE BEST I
CAN COME UP WITH FOR THIS FORECAST PACKAGE.
AFTER TUESDAY...THE BIG QUESTION FOR WEDNESDAY AND THURSDAY IS HOW
WARM DOES IT GET. FIRST...ALTHOUGH FUN TO LOOK AT...THE NAM
TEMPERATURES ARE WAY OVERDONE /111 IN MADISON THURSDAY SEEMS A BIT
MUCH/. INSTEAD FAVORED THIS FORECAST TO THE MORE REASONABLE ECMWF
FOR TEMPS THESE DAYS. EVEN THEN...THURSDAY COULD BE QUITE
INTERESTING AS WE GET SOME GOOD SW FLOW OUT AHEAD OF A WEAK
BOUNDARY THAT WILL BE DROPPING DOWN FROM THE NW. THE ECMWF SHOWS
925 MB TEMPS BETTER THAN 30C COMING INTO SW MN. HAVE TEMPS IN THE
WEST IN THE MID 90S...BUT IF THE ECMWF PANS OUT...WOULD NOT BE
SURPRISED IF WE SEE SOME TRIPLE DIGIT TEMPERATURES IN SW MN.
THURSDAY NIGHT...THE BOUNDARY WILL WASH OUT OVER THE MPX AREA.
THE ECMWF DOES SHOW 925-850 TEMPS BACKING OFF SOME FRIDAY...BUT
SHOULD STILL HAVE NO PROBLEMS SEEING LOWER 90S INTO SRN MN. GOING
INTO THE WEEKEND...THE GFS/ECMWF CONTINUE TO ADVERTISE THE RIDGE
BREAKING DOWN SOME...WITH A DECENT SHORT WAVE WORKING ACROSS THE
NRN TIER OF THE CONUS. THE GFS REMAINS OUT AHEAD OF JUST ABOUT
EVERYTHING WITH THE WAVE...BRINGING ITS ASSOCIATED COLD FRONT
THROUGH SATURDAY. WITH THAT SAID...THE 26.12 ECMWF DID SPEED UP
ITS MOVEMENT OF THE WAVE...WITH THE FRONT COMING THROUGH ABOUT 12
HRS EARLIER THAN ITS 26.00 RUN. IF THE ECMWF PANS OUT...SATURDAY
WILL BRING ABOUT ANOTHER DAY OF HIGHS WELL INTO THE 90S. GIVEN THE
WARM SIGNAL THAT CONTINUES TO SHOW UP THROUGH THE WEEKEND...
CONTINUED TO BOOST ALLBLEND HIGHS BY SEVERAL DEGREES THROUGH THE
EXTENDED. ALSO MAINTAINED SLIGHT CHANCES POPS ACROSS THE NRN CWA
FRI NIGHT THROUGH SATURDAY NIGHT. FRIDAY NIGHT INTO SATURDAY POPS
ARE THERE TO ACCOUNT FOR POTENTIAL ACTIVITY NORTH OF THE WARM
FRONT...WHILE SAT NIGHT WOULD ACCOUNT FOR THE COOL FRONT. CHANCES
DO NOT LOOK ALL THAT GREAT...AS THE REMNANTS OF ISAAC SHOULD
INTERCEPT A LOT OF MOISTURE THAT COULD COME THIS WAY.
ON A RECORDS SIDE NOTE...THE RECORD HIGHS AT EAU/MSP/STC THESE
LAST FEW DAYS OF AUGUST ARE ALL BETWEEN 94 AND 99. SHOULD SEE
HIGHS GET UP IN THIS REGION AT LEAST WEDNESDAY AND THURSDAY...SO
WILL SEE IF WE CAN`T BREAK A RECORD OR TWO IF WE ARE GOING TO GET
THIS WARM.
&&
.AVIATION.../00Z TAF ISSUANCE/
ONLY PROBLEM IN THE OVERNIGHT IS THE POTENTIAL FOR RADIATION FOG.
STILL HAVE SOME HIGHER DEWPOINTS OFF TOT EH SOUTH AND EAST...AND
WINDS ARE RATHER LIGHT WITH HIGH PRESSURE RIDGE IN PLACE. RAP AND TO
A LESSER DEGREE THE 00Z NAM WAS INDICATING SOME POTENTIAL FOR AT
LEAST SOME MVFR FOG. WILL MENTION THAT AT ALL BUT KAXN/KMSP FOR
NOW. KEAU MAY GO DOWN MORE SO DID GO IFR THERE AFTER 10Z. SHOULD
BURN OFF QUICKLY MONDAY MORNING AND SUNSHINE EXPECTED MST OF THE
DAY. THE NAM CONTINUES TO INDICATE SOME POTENTIAL OF MID LEVEL
CLOUDS DEVELOPING LATER MONDAY NIGHT. OVER WESTERN AREAS. WILL
MENTION SOME BASED AC THERE INTO THE EVENING. OTHERWISE VFR AFTER
POSSIBLE FOG TONIGHT. SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT
BECOMING NORTHWEST TO NORTH AND EVENTUALLY NORTHEAST AND THEN
SOUTHEAST OVER WESTERN TAF SITES INTO MONDAY NIGHT. SHOULD REMAIN
LESS THAN 10 KTS.
KMSP...VFR SKC OVERNIGHT THROUGH MONDAY. LIGHT/VARIABLE WIND
OVERNIGHT BECOMING NORTHWEST/NORTH MONDAY AND EVENTUALLY EAST INTO
MONDAY NIGHT. WILL REMAIN BELOW 10 KNOTS.
/OUTLOOK FOR KMSP/
TUESDAY...VFR. WINDS SE AT 5 TO 10 KTS.
WEDNESDAY...VFR. WINDS SW AT 10G15KTS.
THURSDAY...VFR. WINS SSW AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/DE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
317 PM CDT SAT AUG 25 2012
.DISCUSSION...
A DUO OF WEAK SHORTWAVES IS DETECTABLE IN EARLY AFTERNOON RADAR
IMAGERY...ONE ROTATING FROM EAST CENTRAL MN INTO WEST CENTRAL
WISCONSIN...AND THE OTHER OVER NORTHEAST IA. MEANWHILE...THE
PRECIPITATION ASSOCIATED WITH THE NORTHERN STREAM TROUGH OVER
NORTHWEST ONTARIO IS SHIFTING TOWARD LAKE SUPERIOR. THE DYNAMICS
AND 850-700MB MOISTURE TRANSPORT ASSOCIATED WITH THESE FEATURES
WILL CONTINUE SHIFTING EAST OF THE FORECAST AREA DURING THE LATE
AFTERNOON AND EARLY EVENING...WITH ONLY WIDELY SCATTERED SHOWERS
LINGERING OVER WEST CENTRAL WI AFTER DARK. CONCERN THEN SHIFTS TO
CLOUD COVER AND THE POTENTIAL FOR FOG DEVELOPMENT OVERNIGHT.
SURFACE COLD FRONT HAS ENTERED WEST/NORTH CENTRAL MN
TODAY...ALTHOUGH IT WILL WASH OUT PRIOR TO REACHING CENTRAL MN.
WHILE POST-FRONTAL DEWPOINTS ARE IN THE MID TO UPPER 40S...PRE-
FRONTAL DEWPOINTS BETWEEN 65 AND 70 DEGREES ARE COMMON THIS
AFTERNOON ACROSS THE CWFA. THEREFORE...GIVEN THE LIGHT WIND
FIELD...AREAS THAT ARE ABLE TO CLEAR OUT TONIGHT WILL BE
SUSCEPTIBLE TO FOG DEVELOPMENT. THIS APPEARS MOST LIKELY ACROSS
WEST CENTRAL MN. FOR SOUTH CENTRAL MN...SHORT RANGE
MODELS...INCLUDING THE RAP AND THE NAM...INDICATE STRATUS CLOUDS
WILL LIFT OUT OF IOWA OVERNIGHT...SO LOW CEILINGS WILL BE MORE OF
A CONCERN THERE.
ON SUNDAY...A FEW SHOWERS MAY BE LINGERING FROM NEAR EAU CLAIRE TO
LADYSMITH IN THE MORNING. AN OTHERWISE DRY DAY IS EXPECTED...AS THE
AREA REMAINS SANDWICHED BETWEEN THE HUDSON BAY CYCLONE AND THE
AMPLIFYING WESTERN RIDGE. AFTER MORNING FOG AND LINGERING LOW CLOUDS
CLEAR...TEMPERATURES WILL REBOUND INTO THE LOW/MID 80S DURING THE
AFTERNOON UNDER MOSTLY SUNNY SKIES AND LIGHT WEST/SOUTHWEST WINDS.
THE MAIN WEATHER HEADLINE FOR THE UPCOMING WEEK WILL BE VERY WARM
TEMPERATURES...AS THE WESTERN RIDGE EXPANDS INTO THE CENTRAL UNITED
STATE. BY MID WEEK...TEMPERATURES WILL BE AROUND 15 DEGREES ABOVE
NORMAL...WITH HIGHS IN THE UPPER 80S TO LOWER 90S COMMON FROM
TUESDAY THROUGH THURSDAY. STILL CAN/T RULE OUT AN ARBITRARY SHOWER OR
THUNDERSTORM...BUT NO ORGANIZED PRECIPITATION IS ANTICIPATED THROUGH
NEXT WEEK.
THE RIDGE IS EXPECTED TO FLATTEN TOWARD THE END OF THE WORK WEEK
INTO LABOR DAY WEEKEND AS A SHORTWAVE TROUGH TRACKS ACROSS THE
PACIFIC NORTHWEST. THE EVOLUTION OF TC ISAAC WILL COME INTO PLAY
HOWEVER...AND FACTOR INTO HOW MUCH OF A COOL DOWN WE WILL SEE NEXT
WEEKEND. FORECAST CONFIDENCE AFTER FRIDAY IS THEREFORE RATHER LOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
TRICKY FORECAST ALL AROUND AS MOIST SWRLY FLOW WILL...BUT LACK OF
FORCING WILL KEEP BOUTS OF SHOWERS GOING THROUGH MUCH OF THE
EVENING...WITH LOTS OF UNCERTAINTY SURROUNDING FOG/STRATUS
POTENTIAL TONIGHT. COLD FRONT RIGHT NOW NOT MUCH MORE THAN 10
MILES WEST OF AXN...BUT IS QUICKLY LOSING STEAM/DEFINITION THIS
FAR SOUTH. REMNANTS OF MORNING ACTIVITY FROM SW/SC MN NOW WORKING
THROUGH THE CITIES AND WILL BE MOVING INTO WRN WI THIS AFTERNOON.
FOR PRECIP CHANCES THE REST OF THE DAY...WEAK/MOIST SRLY 850 MB
FLOW WILL LIKELY KEEP SPORADIC SHOWERS GOING...BUT EXTENSIVE CLOUD
COVER WILL LIMIT HEATING AND THUNDER POTENTIAL. WILL BASICALLY
STICK WITH VCSH MENTION FOR MOST TAFS INTO THIS EVENING. WILL
LIKELY SEE A SECOND ROUND OF PRECIP COME UP OUT OF IA
TONIGHT...BUT GUIDANCE ALL PRETTY SIMILAR IN KEEPING MOST OF THIS
PRECIP EAST OF EAU. FOR TONIGHT...FOLLOWED THE RAP/NAM AND EXPECT
A BATCH OF LOW CIGS OVER WRN HALF OF IA TO COME UP INTO SRN MN
THEN WRN WI OVERNIGHT...SO HAVE LOW STRATUS MENTION FOR
MSP/RNH/EAU. FOR RWF/STC...IT WILL EITHER BE STRATUS OR FOG. RIGHT
NOW...SIDED WITH STRATUS REMAINING EAST OF THESE LOCATIONS. WITH
NAM BUFKIT SOUNDINGS SCREAMING FOG FOR RWF/STC...HIT THOSE
LOCATIONS HARD FOR FOG OVERNIGHT. AT AXN...DEWPS IN THE 40S ARE
LITERALLY IN THE NEXT COUNTY TO THE WEST. SOME OF THIS DRY AIR
SHOULD WORK IN THROUGH THE DAY...LIMITING THE FOG POTENTIAL THERE
OVERNIGHT...THOUGH IF AXN DOES NOT SEE THIS DRY AIR...THEN THEY
SHOULD FOLLOW STC/RWF INTO THE FOG. FOR WINDS...AXN MAY BRIEFLY GO
NW THIS AFTERNOON...BUT SFC RIDGE BUILDS IN TONIGHT...WHICH WILL
MAKE FOR MAINLY LGT AND VRB WINDS THROUGH THE NIGHT.
KMSP...LOOKING LIKE IT WILL BE DIFFICULT TO GET MUCH MORE PRECIP
AFTER CURRENT BATCH MOVES THROUGH...BUT WITH MOIST LOW LEVEL FLOW
REMAINING THROUGH THE AFTERNOON...WILL LIKELY SEE HIT AND MISS
SHOWERS CONTINUE INTO THE EVENING. GIVEN CLOUDY/COOL TEMPS
TODAY...SHOULD HAVE NO PROBLEM GETTING REDUCED FLIGHT CONDITIONS
OVERNIGHT. AT THE VERY LEAST...WILL LIKELY SEE CIGS BELOW
1700...BUT IFR IS QUITE POSSIBLE AS WELL. SW WINDS WILL DIE OFF
PRETTY QUICK THIS EVENING AND GO LGT AND VRB TONIGHT WITH SFC
RIDGE BUILDING IN. WINDS SUNDAY LOOK TO BE LIGHT AND OUT OF THE WNW.
/OUTLOOK FOR KMSP/
.MONDAY...VFR. WINDS LGT AND VRB.
.TUESDAY...VFR. WINDS S 5-10 KTS.
.WEDNESDAY...VFR. WINDS SW 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
859 PM CDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 852 PM CDT SUN AUG 26 2012
THERE HAS BEEN AN OVERALL DECREASE IN AREA COVERAGE FOR -SHRA/ISOLD
-TSRA OVER THE PAST 1-2 HOURS NOW THAT THE SUN HAS SET AND THE
THROUGH AXIS HAS ENTERED THE NORTHWEST PART OF THE CWA. HAVE
CONTINUED LIKELY POPS OVER THE SRN AND ERN PARTS OF THE CWA INTO
THE OVERNIGHT HOURS WHERE THE RAP IS SHOWING DECENT LOW LEVEL
MOISTURE CONVERGENCE JUST AHEAD OF THE TROUGH. HAVE ALSO BEGAN TO
TRIM BACK ON RAIN CHANCES BEHIND THE TROUGH AXIS. OTHERWISE...
GOING FORECAST LOOKS ON TRACK AND ONLY MADE MINOR TWEAKS TO IT
BASED ON CURRENT TRENDS.
BRITT
&&
.SHORT TERM...
ISSUED AT 237 PM CDT SUN AUG 26 2012
(TONIGHT AND MONDAY)
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TONIGHT
AS MID LEVEL TROF AND SURFACE TROF INTERACT WITH A VERY MOISTURE
RICH ATMOSPHERE. LOCALLY HEAVY DOWNPOURS WILL BE POSSIBLE...BUT
SEVERE WEATHER IS UNLIKELY GIVEN LIMITED INSTABILITY.
THIS AXIS OF RAINFALL WILL SLOWLY SHIFT SOUTHEAST AS DRIER AIR
MOVES IN FROM THE NORTH THANKS TO A SURFACE HIGH. WARMEST
TEMPERATURES ON MONDAY WILL BE NORTH OF INTERSTATE 70 THANKS TO
AFTERNOON SUNSHINE...AND COOLEST SOUTH WHERE CLOUD COVER AND SCT
CONVECTION WILL GRADUALLY COME TO AN END.
CVKING
&&
.LONG TERM...
ISSUED AT 237 PM CDT SUN AUG 26 2012
(TUESDAY THROUGH SUNDAY)
UPPER LEVEL RIDGE WILL BUILD INTO THE MIDWEST WITH SLIGHTLY ABOVE
NORMAL TEMPERATURES EXPECTED THROUGH THURSDAY. HAVE FOLLOWED
LATEST NATIONAL HURRICANE CENTER FORECAST AND HPC GUIDANCE FOR THE
EXTENDED FORECAST WITH THE REMNANTS OF ISAAC BRUSHING THE EASTERN
HALF OF THE CWA LATE THIS WEEK AND EARLY NEXT WEEKEND. CHANGES IN
THE FORECAST INCLUDE CHANCE POPS AND COOLER TEMPERATURES FOR THE
SOUTHEAST HALF OF THE CWA. THIS CHANGE IN THE FORECAST IS DUE TO
THE TRACK OF THE HURRICANE BEING SHIFTED 150 MILES TO THE WEST
OVER THE PAST 24 HOURS BY NHC. MORE CHANGES ARE LIKELY IN THE
TRACK AND THIS WILL OBVIOULSY HAVE A BIG IMPACT ON OUR WEATHER
LATE THIS WEEK AND NEXT WEEKEND. SO STAY TUNED.
CVKING
&&
.AVIATION...
ISSUED AT 640 PM CDT SUN AUG 26 2012
SHOWERS AND A FEW THUDERSTORMS WILL LINGER INTO THE EARLY EVENING
AS THE WAVE DROPS SOUTHEAST ACROSS THE AREA. EXPECT SIGNIFICANT
DECREASE IN PRECIPITATION COVERAGE AFTER SUNSET ALTHOUGH SOME SHOWERS
MAY LINGER ALONG THE TROF. LOTS PF LOW LEVEL MOISTURE WILL LEAD TO
IFR CEILINGS AND FOG INTO MID MORING. MVFR CONDITIONS LIFT BY LATE
AFTERNOON.
SPECIFICS FOR KSTL...MOST OF THE PRECIPITATION WILL MOVE OUT OF
THE AREA BY 04Z. EXPECT IFR CEILINGS AND SOME FOG TO DEVELOP
OVERNIGHT. PRETTY MUCH FOLLOWED WHAT THE IFR/MVRF CEILINGS DID
TODAY OUT TO THE WEST. EVEN THOUGH IT IS AUGUST...WITH LIGHT NORTH
TO NORTHEAST WIND EXPECT THE MVFR CEILINGS TO HOLD UNTIL LATE
AFTERNOON MONDAY.
JPK
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1023 PM EDT SUN AUG 26 2012
.SYNOPSIS...
HIGH PRESSURE NORTH OF THE AREA TONIGHT WILL WEAKEN AND MOVE
OFFSHORE ON MONDAY. ISAAC IS EXPECTED TO BECOME A HURRICANE AS IT
MOVES INTO THE GULF OF MEXICO...MAKING LANDFALL IN COASTAL
MISSISSIPPI EARLY WEDNESDAY MORNING. ALTHOUGH HURRICANE ISAAC WILL
NOT DIRECTLY AFFECT THE EASTERN CAROLINAS...THE INCREASE IN
TROPICAL MOISTURE ACROSS THE REGION MAY BRING INCREASINGLY WET AND
UNSETTLED WEATHER THIS UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 10:30 PM SUNDAY...ISOLATED SHOWERS AND A THUNDERSTORM OR TWO
MAY MOVE ASHORE IN THE CAPE FEAR REGION AS LOW LEVEL CONVERGENCE
ACTS TO FORCE CONVECTIVE DEVELOPMENT. FORECAST ALREADY COVERS
THESE FEATURES. NO CHANGES NEEDED TO THE GOING FORECAST...PREVIOUS
DISCUSSIONS FOLLOW:
EARLIER SEA-BREEZE GENERATED SHOWERS HAVE MAINLY DISSIPATED
ALTHOUGH ISOLATED POP-UPS STILL APPEARING WELL INLAND. OTHER
SHOWERS OVER THE COASTAL WATERS ARE ALSO MOSTLY DISSIPATING AS
THEY ENCOUNTER DRYER AIR NEAR SHORE. SOME OF THESE SHOWERS ARE
JUST MAKING IT TO THE BEACHES BEFORE EVAPORATING. THESE FEATURES
ARE ALL COVERED IN THE LATEST FORECAST. MAIN CHANGES FOR THE NEAR
TERM FORECAST WERE TO SLOW DOWN THE RATE OF COOLING FOR THIS
AFTERNOON AND EVENING AND TO ADD FOG AFTER MIDNIGHT. DO NOT EXPECT
FOG TO BE THICK...MAINLY PATCHY AND SHALLOW.
MID TO UPPER LOW WILL CONTINUE TO LIFT OFF TO THE NORTHEAST WHILE
HIGH PRESSURE RIDGES DOWN INTO THE CAROLINAS FROM NEW ENGLAND.
STRONG SUBSIDENCE AND DRY AIR ALOFT AS EVIDENT IN SOUNDINGS AND
MOISTURE PROFILES...WILL KEEP MOST OF THE DAY SUNNY. TEMPS WILL
REACH BETWEEN 80 AND 85 UNDER BRIGHT SUNSHINE MOST PLACES. A LIGHT
NORTHEAST FLOW WILL BACK AND INCREASE NEAR THE COAST AS SEA BREEZE
STRENGTHENS THIS AFTERNOON. THIS WILL HELP TO PRODUCE SOME
CONVERGENCE AND ALTHOUGH THE ATMOSPHERE REMAINS DRY...ENOUGH LOW
LEVEL RESIDUAL MOISTURE MAINLY FROM CAPE FEAR NORTH WILL PRODUCE
CU. ENOUGH SUBSIDENCE ALOFT SHOULD KEEP CU FAIRLY FLAT AND WILL
LEAVE OUT ANY PCP UNTIL LATER TONIGHT.
AS ISAAC MOVES ACROSS THE FLORIDA KEYS INTO THE GULF OF MEXICO
AND STRENGTHENS...A TIGHTER GRADIENT FLOW WILL PRODUCE AN
INCREASING MOIST ON SHORE FLOW THROUGH TONIGHT. THIS MOIST
SOUTHEAST FLOW WILL PUSH PCP WATER VALUES UP FROM AROUND AND INCH
THIS MORNING UP ABOVE 1.5 INCHES AFTER MIDNIGHT AND CLOSE TO 1.75
INCHES BY MORNING. DEWPOINT TEMPS IN THE MID 60S WILL REACH AROUND
70. OVERALL EXPECT CLOUDS AND ISOLATED SHOWERS TO MOVE ON SHORE
OVERNIGHT WITH INCREASED PCP CHANCES BY DAY BREAK MAINLY CLOSE TO
THE COAST. INLAND AREAS WILL REMAIN DRIER INITIALLY BUT EXPECT
CLOUDS TO MAKE THERE WAY FURTHER INLAND BY MORNING.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 355 PM SUNDAY...RAIN CHANCES INCREASE MONDAY AND TUESDAY AS
INCREASING LOW LEVEL MOISTURE BUMPS UP PRECIPITABLE WATER VALUES
ACROSS THE REGION. DRY AIR ALOFT WILL PLACE LIMITS OF RAIN AMOUNTS
THROUGH MUCH OF THE PERIOD...BUT DEEPER MOISTURE WILL SPREAD INTO
THE CAROLINAS FROM THE EAST AND SOUTH MORE IN EARNEST LATE
TUESDAY. RAIN CHANCES WILL REMAIN HIGHEST ALONG THE COAST AND OUR
SC INTERIOR ESPECIALLY TUESDAY. TEMPERATURES WILL RUN CLOSE TO
NORMAL FOR LATE AUGUST BOTH MONDAY AND TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 355 PM SUNDAY...STILL CONSIDERABLE UNCERTAINTY REVOLVING
AROUND ISAAC`S EVENTUAL PATH AFTER LANDFALL IN THE GULF COAST.
GUIDANCE HAS SHOWN A CONTINUOUS WESTWARD SHIFT IN OVERALL
TRACK...AND AT THE START OF THE PERIOD ISAAC SHOULD BE MAKING
LANDFALL SOMEWHERE NEAR THE MS/AL BORDER. ALTHOUGH ISAAC IS NOT
EXPECTED TO BRING ANY DIRECT IMPACTS HERE...SUBSTANTIAL RAINFALL
IS STILL POSSIBLE MID/LATE WEEK ACROSS THE CAROLINAS.
DEEP E/SE FLOW BETWEEN ATLANTIC HIGH PRESSURE AND ISAAC WILL
ADVECT THE MID LEVEL THETA-E RIDGE ACROSS MOST OF THE
SOUTHEAST...RAISING PWATS ABOVE TWO INCHES WED/THU. AT THE SAME
TIME...WEAK FRONT TRIES TO DROP SOUTHWARD INTO THIS MOIST REGIME
WHICH FORCES SURFACE CONVERGENCE...WHICH IS AIDED BY DECENT 5H AND
3H DYNAMICS. EVEN THOUGH IT LOOKS LIKE ISAAC`S REMNANTS WILL DRIFT
NORTH...WELL WEST OF THIS AREA...THE DEEP CARIBBEAN MOISTURE
COMBINED WITH THE FORCING JUST MENTIONED...STILL CREATES THE
POTENTIAL FOR HEAVY RAIN WED AND THU. WITH SO MUCH
UNCERTAINTY...DO NOT FEEL THAT MUCH IMPROVEMENT CAN BE MADE TO
INHERITED AND WILL LEAVE HIGH-CHC POP AS-IS. TEMPS WED/THU WILL BE
TEMPERED BY CLOUDS AND RAIN...REMAINING BELOW CLIMO FOR HIGHS AND
SLIGHTLY ABOVE FOR LOWS.
FOR FRIDAY INTO THE WKND...HUGE DIFFERENCES EXIST IN POTENTIAL
WEATHER. IF ISAAC ENDS UP WITH THE MORE WESTERN TRACK THROUGH THE
TN VLY...RIDGING AT THE SURFACE AND ALOFT WILL DEVELOP ACROSS THE
CAROLINAS AND MUCH DRIER AND WARMER WEATHER WILL DEVELOP. IF THE
ECMWF SOLUTION IS CORRECT...WE WILL STAY UNSETTLED THROUGH
SATURDAY BEFORE SLOWLY DRYING OUT. LIKE THE CURRENT IDEA OF SLOWLY
DECREASING POP TO SILENT THROUGH THE WKND WITH TEMPS WARMING TO
ABOVE CLIMO BY THE END OF THE PERIOD...AND WILL MAKE ONLY MINOR
ADJUSTMENTS.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
AS OF 23Z...WILL CONTINUE WITH THE FORECAST OF HIGH CONFIDENCE OF
VFR THROUGH THIS 08Z. LOCAL MODELS HRRR AND WRF-4KM SHOW SHOWER
ACTIVITY OFFSHORE MOVING ONSHORE OVERNIGHT. ALREADY HAD A SHOWER
HERE AT ILM WITH THE HRRR FORECAST RIGHT ON. MODELS DO SHOW WAVES
OF MAINLY LIGHT SHOWERS MOVING ONSHORE AFTER 08Z. WILL MENTION
VCSH FOR COASTAL TERMINALS AND TEMPO FOR TSRA AFTER 08Z. WILL
LEAVE INLAND TERMINALS DRY OVERNIGHT AND ON MONDAY AS ANY SHOWER
ACTIVITY WILL BE CLOSER TO THE COAST. HAVE INTRODUCED MVFR IN FOG
ACROSS THE INLAND COUNTIES OVERNIGHT BETWEEN 08Z AND 12Z.
PREVIOUS DISCUSSION MENTIONS THAT TIME HEIGHT PROGS DO INDICATE
LOW LVL MOISTURE INCREASING DRAMATICALLY AT THE COAST TERMINALS
AFTER MIDNIGHT WHICH IS COMMON WITH TROPICAL AIRMASSES...LOW CIGS
OFTEN DO NOT DEVELOP. DUE TO THIS AND DIVERGENT WINDS IN THE LOW
LVLS WILL OMIT MVFR CIGS AT COAST TERMINALS.
EXTENDED OUTLOOK...ISOLATED SHRA/TSRA MON BECOMING SCATTERED TUE.
BEST CHANCE OF SHRA/TSRA/TEMPO IFR TUES EVENING THROUGH THURS
MORNING. VFR DEVELOPING THURS AFTERNOON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 PM SUNDAY...NO CHANGES NEEDED TO THE CURRENT
FORECAST...WHICH IS DETAILED IN PREVIOUS DISCUSSION BELOW. LATEST
ANALYSIS OF THE COASTAL WATERS SHOWS A GENERALLY EASTERLY FLOW IN
THE 10 TO 15 KT RANGE WITH SEAS OF 2 TO 4 FT. SOME 5 FOOTERS ARE
POSSIBLE OVER OUR OUTERMOST WATERS.
HIGH PRESSURE WILL RIDGE DOWN INTO THE CAROLINAS FROM NEW ENGLAND
WHILE ISAAC MOVES ACROSS THE FLORIDA KEYS INTO THE GULF OF MEXICO
THROUGH TONIGHT. AS ISAAC STRENGTHENS THROUGH TONIGHT...THE
GRADIENT WILL TIGHTEN PRODUCING AN INCREASING ON SHORE FLOW.
EXPECT WINDS TO INCREASE UP TO 15 KTS MAINLY SOUTHERN AND OFF
SHORE WATERS THROUGH TONIGHT. THIS PERSISTENT ON SHORE FLOW WILL
PUSH SEAS UP NEAR 5 FT IN OUTER WATERS.
SEAS WILL CONTINUE TO BE DOMINATED BY A LONGER PERIOD SOUTHEAST
SWELL UP TO 10-13 SECONDS AND A SHORTER PERIOD WIND DRIVEN WAVE
PRODUCING OVERALL SEAS BETWEEN 3 AND 5 FT MOST WATERS. EXPECT
SHOWERS TO MOVE ACROSS WATERS INCREASING TOWARD THE COAST BY
DAYBREAK.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 355 PM SUNDAY...SE AND S WINDS EXPECTED MONDAY AND TUESDAY.
WAVE HEIGHTS WILL HOLD IN MAINLY A 3-4 FOOT RANGE...MOSTLY SE
WAVES IN 9-10 SECOND INTERVALS. SOUTHERLY WINDS WILL ADD MINOR
CHOP ON THE WATERS TUESDAY AND LONGER PERIOD WAVES WILL WEAKEN BY
THEN. ISOLATED SHOWERS AND TSTMS WILL BE POSSIBLE ON THE WATERS
BOTH DAYS AS TROPICAL MOISTURE INCREASES OFFSHORE.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 355 PM SUNDAY...CONSIDERABLE UNCERTAINTY STILL EXISTS IN
THE EXTENDED...BUT IT LOOKS LESS LIKELY THAT HAZARDOUS SEA
CONDITIONS WILL DEVELOP. ISAAC WILL BE MAKING LANDFALL IN THE GULF
AT THE START OF THE PERIOD...AND THE GRADIENT BETWEEN THIS SYSTEM
AND HIGH PRESSURE ACROSS THE ATLANTIC OCEAN WILL CREATE SOUTHERLY
WINDS ACROSS THE WATERS...BUT AT SPEEDS ONLY AROUND 10 KTS DUE TO
THE WEAK GRADIENT. CONFIDENCE DECREASES THEREAFTER AS A SURFACE
TROUGH APPROACHES FROM THE NORTH...AND THE OVERALL GRADIENT
BECOMES QUITE DIFFUSE. WINDS WILL BECOME LIGHT AND VARIABLE...AND
MAY EVEN TURN TO THE EAST ACROSS THE NORTHERN WATERS.
FORTUNATELY...THE LIGHT WINDS WILL CREATE VERY LITTLE WIND WAVE
CONTRIBUTION TO THE SPECTRUM. SEAS WILL THEN BE DOMINATED BY A
2-3FT/10SEC SE SWELL. THIS COMBINED WITH THE WEAK WIND WAVES WILL
CREATE 2-4 FT SEAS THROUGH THE PERIOD.
&&
.TIDES/COASTAL FLOODING...
AS OF 355 PM SUNDAY...WAXING MOON WILL BRING INCREASING TIDAL
DEPARTURES THE NEXT SEVERAL DAYS AND A LOW-END COASTAL FLOOD
ADVISORY MAY BE NEEDED FOR DOWNTOWN WILMINGTON ALONG THE CAPE
FEAR RIVER AND POSSIBLY FOR A FEW OF THE BEACHES IN THE UPCOMING
DAYS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK/RGZ
SHORT TERM...MJC
LONG TERM...JDW
AVIATION...MAC
MARINE...MJC/REK/JDW/RGZ
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
732 PM EDT SUN AUG 26 2012
.SYNOPSIS...
HIGH PRESSURE NORTH OF THE AREA TONIGHT WILL WEAKEN AND MOVE
OFFSHORE ON MONDAY. ISAAC IS EXPECTED TO BECOME A HURRICANE AS IT
MOVES INTO THE GULF OF MEXICO...MAKING LANDFALL IN COASTAL
MISSISSIPPI EARLY WEDNESDAY MORNING. ALTHOUGH HURRICANE ISAAC WILL
NOT DIRECTLY AFFECT THE EASTERN CAROLINAS...THE INCREASE IN
TROPICAL MOISTURE ACROSS THE REGION MAY BRING INCREASINGLY WET AND
UNSETTLED WEATHER THIS UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 7:30 PM SUNDAY...EARLIER SEA-BREEZE GENERATED SHOWERS HAVE
MAINLY DISSIPATED ALTHOUGH ISOLATED POP-UPS STILL APPEARING WELL
INLAND. OTHER SHOWERS OVER THE COASTAL WATERS ARE ALSO MOSTLY
DISSIPATING AS THEY ENCOUNTER DRYER AIR NEAR SHORE. SOME OF THESE
SHOWERS ARE JUST MAKING IT TO THE BEACHES BEFORE EVAPORATING.
THESE FEATURES ARE ALL COVERED IN THE LATEST FORECAST. MAIN CHANGES
FOR THE NEAR TERM FORECAST WERE TO SLOW DOWN THE RATE OF COOLING
FOR THIS AFTERNOON AND EVENING AND TO ADD FOG AFTER MIDNIGHT. DO
NOT EXPECT FOG TO BE THICK...MAINLY PATCHY AND SHALLOW. PREVIOUS
DISCUSSION FOLLOWS:
MID TO UPPER LOW WILL CONTINUE TO LIFT OFF TO THE NORTHEAST WHILE
HIGH PRESSURE RIDGES DOWN INTO THE CAROLINAS FROM NEW ENGLAND.
STRONG SUBSIDENCE AND DRY AIR ALOFT AS EVIDENT IN SOUNDINGS AND
MOISTURE PROFILES...WILL KEEP MOST OF THE DAY SUNNY. TEMPS WILL
REACH BETWEEN 80 AND 85 UNDER BRIGHT SUNSHINE MOST PLACES. A LIGHT
NORTHEAST FLOW WILL BACK AND INCREASE NEAR THE COAST AS SEA BREEZE
STRENGTHENS THIS AFTERNOON. THIS WILL HELP TO PRODUCE SOME
CONVERGENCE AND ALTHOUGH THE ATMOSPHERE REMAINS DRY...ENOUGH LOW
LEVEL RESIDUAL MOISTURE MAINLY FROM CAPE FEAR NORTH WILL PRODUCE
CU. ENOUGH SUBSIDENCE ALOFT SHOULD KEEP CU FAIRLY FLAT AND WILL
LEAVE OUT ANY PCP UNTIL LATER TONIGHT.
AS ISAAC MOVES ACROSS THE FLORIDA KEYS INTO THE GULF OF MEXICO
AND STRENGTHENS...A TIGHTER GRADIENT FLOW WILL PRODUCE AN
INCREASING MOIST ON SHORE FLOW THROUGH TONIGHT. THIS MOIST
SOUTHEAST FLOW WILL PUSH PCP WATER VALUES UP FROM AROUND AND INCH
THIS MORNING UP ABOVE 1.5 INCHES AFTER MIDNIGHT AND CLOSE TO 1.75
INCHES BY MORNING. DEWPOINT TEMPS IN THE MID 60S WILL REACH AROUND
70. OVERALL EXPECT CLOUDS AND ISOLATED SHOWERS TO MOVE ON SHORE
OVERNIGHT WITH INCREASED PCP CHANCES BY DAY BREAK MAINLY CLOSE TO
THE COAST. INLAND AREAS WILL REMAIN DRIER INITIALLY BUT EXPECT
CLOUDS TO MAKE THERE WAY FURTHER INLAND BY MORNING.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 355 PM SUNDAY...RAIN CHANCES INCREASE MONDAY AND TUESDAY AS
INCREASING LOW LEVEL MOISTURE BUMPS UP PRECIPITABLE WATER VALUES
ACROSS THE REGION. DRY AIR ALOFT WILL PLACE LIMITS OF RAIN AMOUNTS
THROUGH MUCH OF THE PERIOD...BUT DEEPER MOISTURE WILL SPREAD INTO
THE CAROLINAS FROM THE EAST AND SOUTH MORE IN EARNEST LATE
TUESDAY. RAIN CHANCES WILL REMAIN HIGHEST ALONG THE COAST AND OUR
SC INTERIOR ESPECIALLY TUESDAY. TEMPERATURES WILL RUN CLOSE TO
NORMAL FOR LATE AUGUST BOTH MONDAY AND TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 355 PM SUNDAY...STILL CONSIDERABLE UNCERTAINTY REVOLVING
AROUND ISAAC`S EVENTUAL PATH AFTER LANDFALL IN THE GULF COAST.
GUIDANCE HAS SHOWN A CONTINUOUS WESTWARD SHIFT IN OVERALL
TRACK...AND AT THE START OF THE PERIOD ISAAC SHOULD BE MAKING
LANDFALL SOMEWHERE NEAR THE MS/AL BORDER. ALTHOUGH ISAAC IS NOT
EXPECTED TO BRING ANY DIRECT IMPACTS HERE...SUBSTANTIAL RAINFALL
IS STILL POSSIBLE MID/LATE WEEK ACROSS THE CAROLINAS.
DEEP E/SE FLOW BETWEEN ATLANTIC HIGH PRESSURE AND ISAAC WILL
ADVECT THE MID LEVEL THETA-E RIDGE ACROSS MOST OF THE
SOUTHEAST...RAISING PWATS ABOVE TWO INCHES WED/THU. AT THE SAME
TIME...WEAK FRONT TRIES TO DROP SOUTHWARD INTO THIS MOIST REGIME
WHICH FORCES SURFACE CONVERGENCE...WHICH IS AIDED BY DECENT 5H AND
3H DYNAMICS. EVEN THOUGH IT LOOKS LIKE ISAAC`S REMNANTS WILL DRIFT
NORTH...WELL WEST OF THIS AREA...THE DEEP CARIBBEAN MOISTURE
COMBINED WITH THE FORCING JUST MENTIONED...STILL CREATES THE
POTENTIAL FOR HEAVY RAIN WED AND THU. WITH SO MUCH
UNCERTAINTY...DO NOT FEEL THAT MUCH IMPROVEMENT CAN BE MADE TO
INHERITED AND WILL LEAVE HIGH-CHC POP AS-IS. TEMPS WED/THU WILL BE
TEMPERED BY CLOUDS AND RAIN...REMAINING BELOW CLIMO FOR HIGHS AND
SLIGHTLY ABOVE FOR LOWS.
FOR FRIDAY INTO THE WKND...HUGE DIFFERENCES EXIST IN POTENTIAL
WEATHER. IF ISAAC ENDS UP WITH THE MORE WESTERN TRACK THROUGH THE
TN VLY...RIDGING AT THE SURFACE AND ALOFT WILL DEVELOP ACROSS THE
CAROLINAS AND MUCH DRIER AND WARMER WEATHER WILL DEVELOP. IF THE
ECMWF SOLUTION IS CORRECT...WE WILL STAY UNSETTLED THROUGH
SATURDAY BEFORE SLOWLY DRYING OUT. LIKE THE CURRENT IDEA OF SLOWLY
DECREASING POP TO SILENT THROUGH THE WKND WITH TEMPS WARMING TO
ABOVE CLIMO BY THE END OF THE PERIOD...AND WILL MAKE ONLY MINOR
ADJUSTMENTS.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
AS OF 23Z...WILL CONTINUE WITH THE FORECAST OF HIGH CONFIDENCE OF
VFR THROUGH THIS 08Z. LOCAL MODELS HRRR AND WRF-4KM SHOW SHOWER
ACTIVITY OFFSHORE MOVING ONSHORE OVERNIGHT. ALREADY HAD A SHOWER
HERE AT ILM WITH THE HRRR FORECAST RIGHT ON. MODELS DO SHOW WAVES
OF MAINLY LIGHT SHOWERS MOVING ONSHORE AFTER 08Z. WILL MENTION
VCSH FOR COASTAL TERMINALS AND TEMPO FOR TSRA AFTER 08Z. WILL
LEAVE INLAND TERMINALS DRY OVERNIGHT AND ON MONDAY AS ANY SHOWER
ACTIVITY WILL BE CLOSER TO THE COAST. HAVE INTRODUCED MVFR IN FOG
ACROSS THE INLAND COUNTIES OVERNIGHT BETWEEN 08Z AND 12Z.
PREVIOUS DISCUSSION MENTIONS THAT TIME HEIGHT PROGS DO INDICATE
LOW LVL MOISTURE INCREASING DRAMATICALLY AT THE COAST TERMINALS
AFTER MIDNIGHT WHICH IS COMMON WITH TROPICAL AIRMASSES...LOW CIGS
OFTEN DO NOT DEVELOP. DUE TO THIS AND DIVERGENT WINDS IN THE LOW
LVLS WILL OMIT MVFR CIGS AT COAST TERMINALS.
EXTENDED OUTLOOK...ISOLATED SHRA/TSRA MON BECOMING SCATTERED TUE.
BEST CHANCE OF SHRA/TSRA/TEMPO IFR TUES EVENING THROUGH THURS
MORNING. VFR DEVELOPING THURS AFTERNOON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 7:30 PM SUNDAY...NO CHANGES NEEDED TO THE CURRENT
FORECAST...WHICH IS DETAILED IN PREVIOUS DISCUSSION BELOW. LATEST
ANALYSIS OF THE COASTAL WATERS SHOWS A GENERALLY EASTERLY FLOW IN
THE 10 TO 15 KT RANGE WITH SEAS OF 2 TO 4 FT.
HIGH PRESSURE WILL RIDGE DOWN INTO THE CAROLINAS FROM NEW ENGLAND
WHILE ISAAC MOVES ACROSS THE FLORIDA KEYS INTO THE GULF OF MEXICO
THROUGH TONIGHT. AS ISAAC STRENGTHENS THROUGH TONIGHT...THE
GRADIENT WILL TIGHTEN PRODUCING AN INCREASING ON SHORE FLOW.
EXPECT WINDS TO INCREASE UP TO 15 KTS MAINLY SOUTHERN AND OFF
SHORE WATERS THROUGH TONIGHT. THIS PERSISTENT ON SHORE FLOW WILL
PUSH SEAS UP NEAR 5 FT IN OUTER WATERS.
SEAS WILL CONTINUE TO BE DOMINATED BY A LONGER PERIOD SOUTHEAST
SWELL UP TO 10-13 SECONDS AND A SHORTER PERIOD WIND DRIVEN WAVE
PRODUCING OVERALL SEAS BETWEEN 3 AND 5 FT MOST WATERS. EXPECT
SHOWERS TO MOVE ACROSS WATERS INCREASING TOWARD THE COAST BY
DAYBREAK.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 355 PM SUNDAY...SE AND S WINDS EXPECTED MONDAY AND TUESDAY.
WAVE HEIGHTS WILL HOLD IN MAINLY A 3-4 FOOT RANGE...MOSTLY SE
WAVES IN 9-10 SECOND INTERVALS. SOUTHERLY WINDS WILL ADD MINOR
CHOP ON THE WATERS TUESDAY AND LONGER PERIOD WAVES WILL WEAKEN BY
THEN. ISOLATED SHOWERS AND TSTMS WILL BE POSSIBLE ON THE WATERS
BOTH DAYS AS TROPICAL MOISTURE INCREASES OFFSHORE.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 355 PM SUNDAY...CONSIDERABLE UNCERTAINTY STILL EXISTS IN
THE EXTENDED...BUT IT LOOKS LESS LIKELY THAT HAZARDOUS SEA
CONDITIONS WILL DEVELOP. ISAAC WILL BE MAKING LANDFALL IN THE GULF
AT THE START OF THE PERIOD...AND THE GRADIENT BETWEEN THIS SYSTEM
AND HIGH PRESSURE ACROSS THE ATLANTIC OCEAN WILL CREATE SOUTHERLY
WINDS ACROSS THE WATERS...BUT AT SPEEDS ONLY AROUND 10 KTS DUE TO
THE WEAK GRADIENT. CONFIDENCE DECREASES THEREAFTER AS A SURFACE
TROUGH APPROACHES FROM THE NORTH...AND THE OVERALL GRADIENT
BECOMES QUITE DIFFUSE. WINDS WILL BECOME LIGHT AND VARIABLE...AND
MAY EVEN TURN TO THE EAST ACROSS THE NORTHERN WATERS.
FORTUNATELY...THE LIGHT WINDS WILL CREATE VERY LITTLE WIND WAVE
CONTRIBUTION TO THE SPECTRUM. SEAS WILL THEN BE DOMINATED BY A
2-3FT/10SEC SE SWELL. THIS COMBINED WITH THE WEAK WIND WAVES WILL
CREATE 2-4 FT SEAS THROUGH THE PERIOD.
&&
.TIDES/COASTAL FLOODING...
AS OF 355 PM SUNDAY...WAXING MOON WILL BRING INCREASING TIDAL
DEPARTURES THE NEXT SEVERAL DAYS AND A LOW-END COASTAL FLOOD
ADVISORY MAY BE NEEDED FOR DOWNTOWN WILMINGTON ALONG THE CAPE
FEAR RIVER AND POSSIBLY FOR A FEW OF THE BEACHES IN THE UPCOMING
DAYS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK/RGZ
SHORT TERM...MJC
LONG TERM...JDW
AVIATION...MAC
MARINE...MJC/REK/JDW/RGZ
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
341 AM EDT SAT AUG 25 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE SLOWLY UP THE CAROLINA COAST OVERNIGHT.
HIGH PRESSURE WILL BUILD SOUTH THROUGH SUNDAY...BRINGING SLIGHTLY
DRIER AIR INTO THE REGION. TROPICAL STORM ISAAC IS EXPECTED TO
MOVE INTO THE EASTERN GULF OF MEXICO EARLY NEXT WEEK. REMNANTS OF
ISAAC COULD BRING UNSETTLED WEATHER TO THE CAROLINAS BY THE MIDDLE
OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 PM FRIDAY...ISOLATED SHOWERS CONTINUE WELL INLAND AND
JUST OFFSHORE...WHICH APPEAR TO BE SPINNING AROUND THE PERIPHERY
OF AN UPPER LOW. THESE SHOULD GRADUALLY FADE AS DRYER AIR WORKS IN
OVERNIGHT. PREVIOUS DISCUSSIONS FOLLOW:
LOOKS LIKE WE HAVE FINALLY BROKEN OUR STREAK OF CONSECUTIVE DAYS
AT 70F OR ABOVE...DATING BACK TO JUNE 28TH. THIS WAS A RECORD
STRING OF 56 DAYS. THE PREVIOUS RECORD WAS SET IN 1941 WITH 52
CONSECUTIVE DAYS.
MID TO UPPER LOW WILL TRACK UP THE SOUTHEAST COAST THROUGH
TONIGHT. THE H5 CIRCULATION REMAINS BROAD WITH CENTER TIGHTENING A
BIT OVERNIGHT WITH CENTER FORECAST OVER NC/VA BORDER BY SAT
MORNING. THE ASSOCIATED SURFACE LOW JUST E-SE OF CAPE FEAR THIS
AFTERNOON WILL MOVE NORTH AND BECOME MORE ELONGATED AS IT WEAKENS
THROUGH TONIGHT. NAM STILL SHOWING BEST ENERGY ASSOCIATED WITH
THIS LOW TO MOVE FROM COASTAL WATERS JUST SOUTH OF CAPE FEAR DUE
NORTH INTO NC THIS AFTERNOON. HRRR MODEL SHOWING BEST CHC FOR
HEAVIER PCP FROM THE TIP OF CAPE FEAR NORTH ALONG THE NORTH
CAROLINA COAST MAINLY FROM NEW HANOVER COUNTY THROUGH PENDER
COUNTY. THE BEST CHC OF HEAVIER PCP WILL OCCUR DURING THIS TIME
BUT BULLSEYE FOR HEAVIEST RAIN IN TSTMS WILL REMAIN OVER THE
WATERS TO THE EAST. THE GREATEST THREAT THROUGH WILL BE POTENTIAL
FOR FLOODING AS STEERING FLOW OVER MOST LAND AREAS WILL REMAIN
VERY WEAK. PCP WATER VALUES WILL REMAIN AROUND 2 INCHES UP THE
CAPE FEAR COAST DROPPING OFF AS YOU MOVE INLAND DOWN LESS THAN AN
INCH IN DRIER AIR AND SUBSIDENCE ON BACK END OF LOW WEST OF LOCAL
CWA...OVER CENTRAL TO WESTERN CAROLINAS. WILL KEEP LOW END POPS
INLAND AS SOME ENERGY ROTATES AROUND THE LOW...BUT OVERALL CLOUDS
AND COOLER NORTHERLY FLOW KEEPING TEMPS JUST AROUND 80 AND OVERALL
MORE STABLE ATMOSPHERE.
MODEL SOUNDINGS AND MOISTURE PROFILES SHOWING DRIER AIR WORKING
ITS WAY IN ON THE BACK EDGE OF LOW THROUGH THE MID TO UPPER
LEVELS TONIGHT AS IT LIFTS OFF TO THE NORTH. THIS WILL HELP PCP
SHUT OFF OVER LOCAL AREA. NAM SHOWS PCP WATER VALUES DROPPING
DOWN LESS THAN 1.5 INCHES BY SAT MORNING. CLOUDS...PCP AND FOG
WILL HELP KEEP TEMPS IN THE MID 60S AND CLOSER TO 70 WHERE GREATER
DEWPOINT AIR WILL HANG ON THE LATEST. MAY SEE STRATUS DEVELOP AS
MOISTURE BECOMES TRAPPED UNDER LOW LEVEL INVERSION...MORE PROBABLE
CLOSER TO THE COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...EXITING MID LEVEL TROUGH/LOW SUN LEAVES WEAK
5H RIDGING BEHIND WHILE AT THE SURFACE HIGH PRESSURE CONTINUES TO
EXTEND SOUTH ACROSS THE PIEDMONT. DEEP DRY AIR IN PLACE SUN WILL
LIMIT DEPTH OF CONVECTION...THOUGH HEATING WILL YIELD A FAIRLY
SIGNIFICANT FLAT CU FIELD. SUN NIGHT INTO MON BECOMES PROBLEMATIC AS
THE TRACK OF ISAAC WILL PLAY SIGNIFICANT ROLE IN HOW MUCH AND HOW
QUICKLY THE LARGE PLUME OF TROPICAL MOISTURE ASSOCIATED WITH THE
STORM REACHES THE AREA.
A LOOK AT FORECAST SOUNDINGS SEVERAL DIFFERENT MODELS SHOWS DEEP
MOISTURE IN PLACE ON MON...PRECIPITABLE WATER VALUES REACH 2 INCHES
ACROSS MUCH OF THE AREA...AND LOW LEVEL CONVERGENCE ALONG THE COAST
COMBINED WITH THE DEEP MOISTURE SHOULD PRODUCE CONVECTION EARLY MON.
DIURNAL INSTABILITY COMBINED WITH WEAK LOW LEVEL CONVERGENCE WILL
HELP CONVECTION SPREAD INLAND...BUT LIMITED DYNAMICAL SUPPORT WILL
KEEP ACTIVITY AWAY FROM THE IMMEDIATE COAST LIMITED TO THE
AFTERNOON/EVENING HOURS MON. THINK CONVECTION OVER THE WATERS WILL
CONTINUE MON NIGHT WITH FLOW PUSHING ANY ACTIVITY ONSHORE...WHERE IT
WILL DISSIPATE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...LONG TERM FORECAST REMAINS QUITE CHALLENGING
WITH ISAAC PLAYING A SIGNIFICANT ROLE. THE LACK OF A CLEAR TRACK ONCE
THE STORM MAKES LANDFALL LEADS TO LOW CONFIDENCE IN THE WED THROUGH
FRI FORECAST. DEEP TROPICAL MOISTURE AND WEAK DIVERGENCE ALOFT
ENHANCING INCREASING LOW LEVEL DIVERGENCE WILL LEAD TO AN INCREASE
IN PRECIP COVERAGE TUE INTO TUE NIGHT. IT IS AT THIS POINT WHERE
FORECAST BECOMES LESS CLEAR. THE 00Z RUN OF THE GFS HAS DONE NOTHING
TO INCREASE CONFIDENCE. THE CAUSE OF THIS IS 2 5H RIDGES...ON TO THE
NORTHWEST AND ONE TO THE EAST/SOUTHEAST...WHICH FORM A BLOCKING
PATTERN. THE ECMWF SOLUTION HAS BEEN TO SHOW THE 5H RIDGE OVER THE
CENTRAL US BREAKING DOWN WHILE A MAJORITY OF THE GFS SOLUTIONS HAVE
HELD THIS PORTION OF THE BLOCK STRONG. BLOCK PATTERN ARE NOTORIOUS
FOR GIVING GUIDANCE FITS AND HAVE A FEELING THE ULTIMATE SOLUTION
WILL REMAIN CLOUDED FOR THE NEXT FEW DAYS. AS THE INHERITED FORECAST
IS A GOOD COMPROMISE BETWEEN THE SOLUTIONS...WITH A SLIGHT LEAN IN
FAVOR OF THE GFS...CANNOT SEE ANY REASON TO DEVIATE UNTIL THE TRACK
OF ISAAC AND ITS REMNANTS BECOMES CLEARER. THUS ONLY SIGNIFICANT
CHANGES WILL BE SLIGHT UPWARD ADJUSTMENT TO POP LATE IN THE PERIOD.
HIGHS WILL BE WITHIN A COUPLE DEGREES OF CLIMO THROUGH THE
PERIOD...WITH LOWS HELD A BIT ABOVE CLIMO BY CLOUD COVER AND LOW
LEVEL WINDS.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...A CLOSED MID-LEVEL LOW HAS MANIFESTED ITSELF ACROSS THE
ILM CWA THIS EARLY AM. DYNAMICS ASSOCIATED WITH THE LOW ALONG WITH
THE COLD POOL ALOFT...WILL BOTH COMBINE TO PRODUCE VCSH OR POSSIBLY
A SHORT PERIOD OF PREDOMINATE R- OR R DURING THE PRE-DAWN HRS ACROSS
MAINLY INLAND PORTIONS OF THE ILM CWA...EXTENDING FROM LBT TO
POSSIBLY FLO. WILL GO WITH THE MORE OPTIMISTIC FORECAST AND SAY THE
COLD POOL/CLOSED LOW LIFTS FAR ENOUGH NORTH OF THE AREA TODAY. THIS
WILL ALLOW DRIER AIR TO INFILTRATE THE ILM CWA...AS SEEN WITH THE
LATEST WATER VAPOR IMAGERY TRENDS. LOOK FOR VFR CONDITIONS BY
14Z-16Z...WHICH WILL CONTINUE FOR THE REMAINDER OF THE FORECAST
PERIOD. FOR THE COASTAL TERMINALS...A WEAK N TO NE SFC WIND AROUND 5
KT EARLY THIS AFTERNOON WILL VEER TO THE E-SE THIS AFTERNOON DUE TO
A WEAK RESULTANT WIND OR WEAK SEA BREEZE. ANY CLOUDINESS LEFT THIS
AFTERNOON WILL LIKELY DISSIPATE OR FADE AWAY LEAVING A MOSTLY CLEAR
SKY TO START THE OVERNITE PERIOD.
EXTENDED OUTLOOK...ISOLATED SHRA/TSRA MON. BETTER CHANCE OF SHOWERS
AND STORMS TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 PM FRIDAY...LATEST OBS SHOW WINDS ARE SETTLING INTO A
NORTHWESTERLY FLOW...WITH WINDS NOW IN THE 10 TO 15 KT
RANGE...HIGHEST NORTH. SEAS RANGE FROM 2 TO 4 FT. NO CHANGES TO
THE GOING FORECAST...PREVIOUS DISCUSSION FOLLOWS:
SFC WINDS OF AROUND 15 KTS WILL DIMINISH A BIT OVERNIGHT AS THEY
BACK TOWARD THE NW. THIS OFF-SHORE FLOW WILL ACT TO LOWER SEAS BUT
A LONGER PERIOD E-SE SWELL UP TO 16 SECONDS WILL COUNTERACT THIS
OFF SHORE FLOW AND WILL PRODUCE A SLIGHT INCREASE IN OVERALL SEAS
OVERNIGHT. SEAS WILL BUILD TO 3 TO 4 FT MAINLY ACROSS THE OUTER
WATERS. EXPECT ROUGHER SEAS WITH HIGHER WINDS AND SEAS IN TSTMS
THROUGH THIS EVENING AND ALSO REDUCED VSBYS DUE TO HEAVY RAIN.
RADAR CONTINUED TO SHOW THE POSSIBILITY OF WATERSPOUTS IN STORMS
OVER THE OUTER COASTAL WATERS THIS AFTERNOON.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...NORTHERLY FLOW AROUND EAST SIDE OF INLAND HIGH
PRESSURE SUN WILL VEER TO EASTERLY SUN NIGHT INTO MON. REMAINS OF
STALLED FRONT/COASTAL TROUGH MOVE ONSHORE MON WITH SOUTHEAST FLOW
DEVELOPING OVER THE WATERS. AT THIS POINT IT APPEARS ANY IMPACT FROM
ISAAC THROUGH THE END OF THE PERIOD WOULD BE LIMITED. GRADIENT
REMAINS MORE OR LESS STATIC THROUGH THE PERIOD WITH WINDS GENERALLY
ON THE LOW SIDE OF THE 10 TO 15 KT RANGE. SEAS 3 TO 5 FT THROUGH THE
PERIOD...A MIX OF NORTHEAST TO EAST WIND WAVE AND SOUTHEAST SWELL.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...POST LANDFALL TRACK OF ISAAC WILL PLAY A
SIGNIFICANT ROLL IN DETERMINING THE WIND FIELD LATE IN THE PERIOD.
SOUTHERLY FLOW IS ANTICIPATED TUE WITH ISAAC TRACKING WEST OF
FL...EVENTUALLY MAKING LANDFALL LATER TUE ON THE FL PANHANDLE.
GRADIENT BETWEEN ISAAC AND BERMUDA HIGH WILL PRODUCE SOUTHEAST FLOW
IN THE 10 TO 15 KT RANGE. WHILE SOUTHERLY FLOW SHOULD CONTINUE ON
WED...THE TRACK OF ISAAC WILL BE A SIGNIFICANT FACTOR IN DETERMINING
HOW STRONG THE SOUTHERLY FLOW OVER THE WATERS WILL BE. CURRENT
FORECAST IS 15 TO 20 KT WED BUT HAVE LOW CONFIDENCE IN THE TRACK OF
ISAAC AFTER IT MOVES INTO SOUTHERN AL/GA. IT IS QUITE POSSIBLE WINDS
COULD END UP HIGHER BY 10 OR 15 KT...ESPECIALLY ACROSS SC WATERS
LATE WED. THIS UNCERTAINTY ALSO TRANSLATES INTO THE SEAS FORECAST
FOR WED...WHERE HEIGHTS COULD CREEP CLOSE TO DOUBLE DIGITS LATE IN
THE PERIOD IF THE MORE PESSIMISTIC FORECAST VERIFIES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK/RGZ
SHORT TERM...III
LONG TERM...III
AVIATION...DCH/43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
140 AM EDT SAT AUG 25 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE SLOWLY UP THE CAROLINA COAST OVERNIGHT.
HIGH PRESSURE WILL BUILD SOUTH THIS WEEKEND...BRINGING SLIGHTLY
DRIER AIR INTO THE REGION. TROPICAL STORM ISAAC IS EXPECTED TO
MOVE INTO THE EASTERN GULF OF MEXICO EARLY NEXT WEEK. REMNANTS
OF ISAAC COULD BRING UNSETTLED WEATHER TO THE CAROLINAS BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 10:30 PM FRIDAY...ISOLATED SHOWERS CONTINUE WELL INLAND AND
JUST OFFSHORE...WHICH APPEAR TO BE SPINNING AROUND THE PERIPHERY
OF AN UPPER LOW. THESE SHOULD GRADUALLY FADE AS DRYER AIR WORKS IN
OVERNIGHT. PREVIOUS DISCUSSIONS FOLLOW:
LOOKS LIKE WE HAVE FINALLY BROKEN OUR STREAK OF CONSECUTIVE DAYS
AT 70F OR ABOVE...DATING BACK TO JUNE 28TH. THIS WAS A RECORD
STRING OF 56 DAYS. THE PREVIOUS RECORD WAS SET IN 1941 WITH 52
CONSECUTIVE DAYS.
MID TO UPPER LOW WILL TRACK UP THE SOUTHEAST COAST THROUGH
TONIGHT. THE H5 CIRCULATION REMAINS BROAD WITH CENTER TIGHTENING A
BIT OVERNIGHT WITH CENTER FORECAST OVER NC/VA BORDER BY SAT
MORNING. THE ASSOCIATED SURFACE LOW JUST E-SE OF CAPE FEAR THIS
AFTERNOON WILL MOVE NORTH AND BECOME MORE ELONGATED AS IT WEAKENS
THROUGH TONIGHT. NAM STILL SHOWING BEST ENERGY ASSOCIATED WITH
THIS LOW TO MOVE FROM COASTAL WATERS JUST SOUTH OF CAPE FEAR DUE
NORTH INTO NC THIS AFTERNOON. HRRR MODEL SHOWING BEST CHC FOR
HEAVIER PCP FROM THE TIP OF CAPE FEAR NORTH ALONG THE NORTH
CAROLINA COAST MAINLY FROM NEW HANOVER COUNTY THROUGH PENDER
COUNTY. THE BEST CHC OF HEAVIER PCP WILL OCCUR DURING THIS TIME
BUT BULLSEYE FOR HEAVIEST RAIN IN TSTMS WILL REMAIN OVER THE
WATERS TO THE EAST. THE GREATEST THREAT THROUGH WILL BE POTENTIAL
FOR FLOODING AS STEERING FLOW OVER MOST LAND AREAS WILL REMAIN
VERY WEAK. PCP WATER VALUES WILL REMAIN AROUND 2 INCHES UP THE
CAPE FEAR COAST DROPPING OFF AS YOU MOVE INLAND DOWN LESS THAN AN
INCH IN DRIER AIR AND SUBSIDENCE ON BACK END OF LOW WEST OF LOCAL
CWA...OVER CENTRAL TO WESTERN CAROLINAS. WILL KEEP LOW END POPS
INLAND AS SOME ENERGY ROTATES AROUND THE LOW...BUT OVERALL CLOUDS
AND COOLER NORTHERLY FLOW KEEPING TEMPS JUST AROUND 80 AND OVERALL
MORE STABLE ATMOSPHERE.
MODEL SOUNDINGS AND MOISTURE PROFILES SHOWING DRIER AIR WORKING
ITS WAY IN ON THE BACK EDGE OF LOW THROUGH THE MID TO UPPER
LEVELS TONIGHT AS IT LIFTS OFF TO THE NORTH. THIS WILL HELP PCP
SHUT OFF OVER LOCAL AREA. NAM SHOWS PCP WATER VALUES DROPPING
DOWN LESS THAN 1.5 INCHES BY SAT MORNING. CLOUDS...PCP AND FOG
WILL HELP KEEP TEMPS IN THE MID 60S AND CLOSER TO 70 WHERE GREATER
DEWPOINT AIR WILL HANG ON THE LATEST. MAY SEE STRATUS DEVELOP AS
MOISTURE BECOMES TRAPPED UNDER LOW LEVEL INVERSION...MORE PROBABLE
CLOSER TO THE COAST.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 340 PM FRIDAY...A DRIER PATTERN ANTICIPATED THIS WEEKEND...AS
DRY MID-LEVEL AIR OVERSPREADS THE REGION...AND A SURFACE LOW PULLS
SLUGGISHLY NORTH AND AWAY FROM OUR AREA. WEAK UPPER LOW POSITIONED
JUST NORTH OF OUR AREA SATURDAY AND SUNDAY WILL CONTINUE TO FEED
DRY AIR ALOFT...BUT CONCURRENTLY SHOULD PROMPT PLENTY OF DIURNAL
BUT MOSTLY CAPPED CUMULUS. CONVERGENCE OFFSHORE LATE IN THE PERIOD
MAY BRING COASTAL SHOWERS SUNDAY NIGHT. WHILE A SHOWER CANNOT BE
RULED OUT ON THE SEA BREEZE FRONT THIS WEEKEND...ACTIVITY SHOULD
IN OR BELOW THE ISOLATED CATEGORY.
MAXIMUM TEMPS WITH PARTIAL CLOUDS AND HIGH PRESSURE WEDGED IN FROM
THE NORTH...SHOULD RESULT IN MAINLY MIDDLE AND UPPER 80S BOTH DAYS.
MINIMUM TEMPS WILL DIP BELOW 70 MOST LOCATIONS BY DAYBREAK SAT/SUN
BUT QUITE A BIT MORE MILD AT THE COAST IN ONSHORE WIND DIRECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 340 PM FRIDAY...SENSIBLE WEATHER THROUGH THE EXTENDED WILL
DEPEND ALMOST ENTIRELY ON ISAAC AND HIS POTENTIAL IMPACTS TO THE
REGION. STILL CONSIDERABLE UNCERTAINTY DUE TO TRACK
FORECASTS...WHICH...UNFORTUNATELY...WILL CREATE SIGNIFICANT
DIFFERENCES IN THE WEATHER ACROSS THE ILM CWA.
GFS/CMC ARE IN DECENT AGREEMENT WITH THEIR OVERALL EVOLUTION OF
ISAAC WHEN COMPARED TO THE ECMWF WHICH IS THE OUTLIER OF THE THREE
MODELS. WHILE THE ECMWF SLOWLY BRINGS ISAAC UP THROUGH THE GULF
COAST AND MEANDERS IT NW INTO THE TN VLY THROUGH MIDWEEK BEFORE
DISSIPATING...THE GFS/CMC BRING IT SLIGHTLY FURTHER EAST INTO THE
PANHANDLE OF FLORIDA ON TUESDAY AND THEN MAKE A SHARP
RECURVE...MOVING ISAAC`S REMNANTS BASICALLY OVER THE ILM CWA ON
WEDNESDAY. WILL LEAN TOWARDS THE GFS/CMC CONSENSUS...THE THINKING
THAT THE LARGE RIDGE WHICH FORCES THE ECMWF SOLUTION TO REMAIN WEST
IS OVERDONE. THIS MEANS DEEP S/SE FLOW MON/TUE WHICH SHOULD SUPPORT
ADVECTION SHOWERS...ESPECIALLY NEAR THE COAST...AND THEN A MUCH
WETTER DAY WEDNESDAY AS MID LEVEL THETA-E RIDGE ASSOCIATED WITH
ISAAC AND ITS REMNANTS...MOVES OVERHEAD. BY THURSDAY WE SHOULD BE ON
THE DRY WEST SUBSIDENT SIDE OF THE STORM AND WILL DRY OUT FOR LATE
WEEK. STILL MUCH UNCERTAINTY...BUT WILL RAMP POP UPWARDS THROUGH
WEDNESDAY BEFORE RAPIDLY TAILING OFF ON THURSDAY/FRIDAY.
NOTE THAT CURRENT FORECAST IS AT LEAST SLIGHTLY DIFFERENT THAN
HPC/NHC WHICH IS FAVORING A MUCH MORE WESTERN AND SLOWER
TRACK...ECMWF...FOR ISAAC. IF THE ECMWF TRACK WERE TO
VERIFY...WEDNESDAY WOULD STILL BE THE WETTEST DAY...SO POP TRENDS
WOULD STILL BE CORRECT...BUT OVERALL LESS RAINFALL ALONG WITH SLOWER
DECREASE IN POP WOULD BE NEEDED IN THAT SOLUTION (I.E. BETTER RAIN
CHANCES CONTINUING THROUGH THE END OF THE WEEK). WILL HAVE TO
MONITOR GUIDANCE TRENDS AND MODIFY FURTHER FORECAST UPDATES AS
NEEDED.
TEMPS WILL BE AROUND CLIMO MOST DAYS...WARMING TO ABOVE BY THE END
OF THE WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...A CLOSED MID-LEVEL LOW HAS MANIFESTED ITSELF ACROSS THE
ILM CWA THIS EARLY AM. DYNAMICS ASSOCIATED WITH THE LOW ALONG WITH
THE COLD POOL ALOFT...WILL BOTH COMBINE TO PRODUCE VCSH OR POSSIBLY
A SHORT PERIOD OF PREDOMINATE R- OR R DURING THE PRE-DAWN HRS ACROSS
MAINLY INLAND PORTIONS OF THE ILM CWA...EXTENDING FROM LBT TO
POSSIBLY FLO. WILL GO WITH THE MORE OPTIMISTIC FORECAST AND SAY THE
COLD POOL/CLOSED LOW LIFTS FAR ENOUGH NORTH OF THE AREA TODAY. THIS
WILL ALLOW DRIER AIR TO INFILTRATE THE ILM CWA...AS SEEN WITH THE
LATEST WATER VAPOR IMAGERY TRENDS. LOOK FOR VFR CONDITIONS BY
14Z-16Z...WHICH WILL CONTINUE FOR THE REMAINDER OF THE FORECAST
PERIOD. FOR THE COASTAL TERMINALS...A WEAK N TO NE SFC WIND AROUND 5
KT EARLY THIS AFTERNOON WILL VEER TO THE E-SE THIS AFTERNOON DUE TO
A WEAK RESULTANT WIND OR WEAK SEA BREEZE. ANY CLOUDINESS LEFT THIS
AFTERNOON WILL LIKELY DISSIPATE OR FADE AWAY LEAVING A MOSTLY CLEAR
SKY TO START THE OVERNITE PERIOD.
EXTENDED OUTLOOK...ISOLATED SHRA/TSRA MON. BETTER CHANCE OF SHOWERS
AND STORMS TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 PM FRIDAY...LATEST OBS SHOW WINDS ARE SETTLING INTO A
NORTHWESTERLY FLOW...WITH WINDS NOW IN THE 10 TO 15 KT
RANGE...HIGHEST NORTH. SEAS RANGE FROM 2 TO 4 FT. NO CHANGES TO
THE GOING FORECAST...PREVIOUS DISCUSSION FOLLOWS:
SFC WINDS OF AROUND 15 KTS WILL DIMINISH A BIT OVERNIGHT AS THEY
BACK TOWARD THE NW. THIS OFF-SHORE FLOW WILL ACT TO LOWER SEAS BUT
A LONGER PERIOD E-SE SWELL UP TO 16 SECONDS WILL COUNTERACT THIS
OFF SHORE FLOW AND WILL PRODUCE A SLIGHT INCREASE IN OVERALL SEAS
OVERNIGHT. SEAS WILL BUILD TO 3 TO 4 FT MAINLY ACROSS THE OUTER
WATERS. EXPECT ROUGHER SEAS WITH HIGHER WINDS AND SEAS IN TSTMS
THROUGH THIS EVENING AND ALSO REDUCED VSBYS DUE TO HEAVY RAIN.
RADAR CONTINUED TO SHOW THE POSSIBILITY OF WATERSPOUTS IN STORMS
OVER THE OUTER COASTAL WATERS THIS AFTERNOON.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 340 PM
FRIDAY...OUTSIDE OF TSTMS WINDS WILL REMAIN MANAGEABLE SATURDAY
AND SUNDAY...AS A SURFACE LOW OVER THE WATERS MOVES SLOWLY NORTH
OF THE AREA. WINDS WILL VEER EAST SUNDAY AS HIGH PRESSURE
CONSOLIDATES OVER NEW ENGLAND. THE COMBINATION OF WIND- WAVES AND
SWELL WAVES WILL KEEP SEAS MAINLY 3-4 FEET THIS WEEKEND AND UP TO
5 FEET AT TIMES WELL OFFSHORE. NUMEROUS SHOWERS AND TSTMS WILL
BECOME SCATTERED TO ISOLATED THIS WEEKEND...AS THE SFC LOW PULLS
NORTH OF SURF CITY BY DAYBREAK SATURDAY...AND DRY AIR ALOFT HELPS
TO SQUELCH STORM DEVELOPMENT.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 340 PM FRIDAY...QUITE A BIT OF UNCERTAINTY THROUGH THE
EXTENDED AS WIND/WAVE CONDITIONS COULD VARY CONSIDERABLY DEPENDING
ON WHAT HAPPENS WITH TS ISAAC. ANTICIPATE E/SE WINDS MON THROUGH TUE
AS ISAAC MOVES ALONG THE WEST COAST OF FLORIDA AND INTO THE GULF
COAST REGION. THE CONTINUED E/SE WINDS AROUND 10 KTS...UP TO 15 KTS
ACROSS THE SOUTHERN WATERS...WILL GENERATE 2-4 FT SOUTHERLY WIND
WAVES. THESE WIND WAVES WILL COMBINE WITH WHAT SHOULD BE INCREASING
S/SE SWELL OF 4-5FT/9SEC DUE TO TROPICAL SYSTEMS ISAAC AND JOYCE.
GUIDANCE IS NOT VERY ROBUST IN DEVELOPING ANY SIGNIFICANT VERY LONG
PERIOD SWELL...BUT NEVERTHELESS...3-5 FT SEAS ARE EXPECTED THROUGH
TUESDAY...WITH 6 FOOTERS POSSIBLE ACROSS THE SOUTHERN WATERS. SEAS
COULD BUILD MUCH HIGHER WEDNESDAY...ESPECIALLY IF GFS/CMC ARE
CORRECT...DUE TO INCREASING SOUTHERLY WINDS...AND SMALL CRAFT
ADVISORY CONDITIONS WILL BE POSSIBLE AT THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK/RGZ
SHORT TERM...MJC
LONG TERM...JDW
AVIATION...DCH/DL
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1017 AM CDT SAT AUG 25 2012
.DISCUSSION...
15 UTC SURFACE ANALYSIS SHOWS A COLD FRONT FROM BAUDETTE TO NEAR
WAHPETON. ALONG THIS LINE IS A BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS...MOVING TO THE EAST-NORTHEAST AROUND 30 KTS. EXPECT
THE MAJORITY OF THIS PRECIPITATION TO MOVE OUT OF THE FORECAST AREA
BY 18 UTC. SOME RE-DEVELOPMENT IS POSSIBLE ACROSS THE FAR EAST THIS
AFTERNOON...BUT ALL OTHER AREAS WILL BE DRY AND SUNNY. NOT EVEN A
HINT OF THERMAL CUMULUS WITH CONVECTIVE TEMPERATURES IN THE 90S TO
NEAR 100 DEGREES. TRIMMED BACK EDGE OF POPS THE REST OF THE DAY
WITH ONLY A 20 TO 30 PERCENT CHANCE OF SHOWERS AND STORMS FROM
BEMIDJI TO PARK RAPIDS AND POINTS EAST THIS AFTERNOON. HIGHEST
INSTABILITY AXIS HAS MOVED INTO THE MN ARROWHEAD AND DO NOT EXPECT
ANY SEVERE WEATHER THE REST OF THE DAY.
STRONG COLD AIR ADVECTION BEHIND THE FRONT WILL RESULT IN
TEMPERATURES 10 TO 15 DEGREES COOLER THAN YESTERDAY WITH AFTERNOON
HIGHS IN THE MID 70S TO NEAR 80 DEGREES. BOUNDARY LAYER DEEPENS TO
BETWEEN 850 AND 750 HPA THIS AFTERNOON WITH 20 TO 30 KTS TO MIX TO
THE SURFACE. EXPECT BREEZY WESTERLY WINDS...ESPECIALLY ACROSS THE
DEVILS LAKE BASIN. DEVILS LAKE AND LANGDON ARE ALREADY GUSTING TO
25 PLUS KNOTS...BUT 14 UTC RAP SHOWS WINDS ALOFT DECREASING A BIT
THROUGH THE DAY...SO DO NOT EXPECT THE NEED FOR ANY KIND OF
ADVISORY.
&&
.AVIATION...
THE FRONTAL BOUNDARY THAT WAS OVER THE RIVER VALLEY EARLY THIS
MORNING HAS CLEARED ALL TAF SITES BY MID MORNING WITH THE
EXCEPTION OF KBJI. TSRA CONTINUE TO MOVE EASTWARD IMPACTING KBJI
BETWEEN 15Z AND 17Z. KBJI WILL CONT TO HAVE MVFR CIGS THROUGH THE
DAY WHILE THE REST OF THE SITES WILL BE VFR. NW WINDS THAT WERE
OCCURRING EARLIER WILL PRIMARILY BE WLY FOR ALL SITES THIS AFTN.
EXPECT WIND GUST AT KDVL TO REMAIN ABOVE 25 KTS UNTIL 00Z.
&&
.PREV DISCUSSION... /ISSUED 430 AM CDT SAT AUG 25 2012/
SHORT TERM.../TODAY THROUGH MONDAY NIGHT.
WATER VAPOR LOOP INDICATED UPPER LEVEL TROUGH OVER SASK. UPPER LOW
WILL MOVE OVER HUDSON BAY BY SUN. COLD FRONT HAS MOVED INTO EASTERN
ND AND WILL CONTINUE MOVING EAST TODAY.
THUNDERSTORMS WERE OCCURRING IN 700 HPA THETA-E RIDGE. SURFACE WIND
SHIFT REMAINS TO THE WEST AND IS FORECAST TO SWEEP ACROSS THE
FORECAST AREA THIS MORNING. HOWEVER FRONT SLOWS DOWN THIS AFTERNOON
OVER SOUTHEAST ZONES. WILL KEEP POPS FARTHER WEST THIS AFTERNOON.
ELEVATED SHOWERS OVER WESTERN ND WILL MOVE EAST TODAY.
LITTLE OR NO PRECIPITATION EXPECTED REST OF SHORT TERM. TEMPERATURES
WERE TWEAKED. COOLER FOR MON NIGHT WITH UPPER RIDGE BUILDING TO THE
WEST.
LONG TERM (TUE THROUGH FRI)...
THE EXTENDED PERIOD WILL START OUT WARM WITH TEMPS WELL ABOVE NORMAL
WITH AN UPPER RIDGE...AND 850MB TEMPS AROUND +25C IN THE VALLEY ON
WED. THERE WILL BE A COLD FRONT THAT MOVES THROUGH THE REGION WED
NIGHT AND THU...AND THERE WILL BE SOME LOW CHANCES FOR SHOWERS AND
STORMS. NOT TOO EXCITED ABOUT CONVECTION THOUGH WITH MOISTURE RETURN
IN QUESTION...BUT WILL LEAVE IN LOW CHANCES FOR PRECIP WED NIGHT INTO
THU NIGHT. TEMPS SHOULD COOL TO NEAR NORMAL BY THE END OF NEXT WEEK
WITH DRY WEATHER EXPECTED ONCE AGAIN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
ROGERS/FRAZIER/HOPPES/DK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
831 PM EDT SUN AUG 26 2012
.SYNOPSIS...
AN UPPER LOW OVER NORTHWEST VIRGINIA THIS EVENING WILL WEAKEN AS
IT LIFTS SLOWLY TOWARD THE DELMARVA TONIGHT. THIS CIRCULATION
WILL BE ABSORBED INTO A LARGER SCALE TROUGH MOVING EASTWARD FROM
THE GREAT LAKES INTO THE NORTHEAST STATES THROUGH MONDAY NIGHT.
THE GREAT LAKES TROUGH WILL SEND A COLD FRONT ACROSS THE REGION BY
EARLY TUESDAY. HIGH PRESSURE WILL SHIFT SOUTHEAST FROM THE UPPER
MIDWEST INTO PENNSYLVANIA FOR THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
STEADIER STRATIFORM RAINFALL IS NOW DECREASING...WITH THE MOST
ORGANIZED ACTIVITY PUSHING NORTHWARD ALONG THE WEAKENED OUTFLOW
WHICH BROUGHT LOCALIZED 40-45 MPH GUSTS TO THE CENTRAL MOUNTAINS
EARLIER THIS EVENING. WINDS NOT NEARLY AS STRONG NOW...BUT WILL
SEE THE OUTFLOW PUSH NORTH OF COUDERSPORT AND MANSFIELD SHORTLY
WITH SOME 30 MPH GUSTS AND BRIEF MODERATE TO HEAVY SHOWERS.
LIGTHNING HAS DWINDLED AS WELL...SO WILL DROP TSTORM MENTIONS FOR
THE NIGHT AS WELL.
DROPPED FLASH FLOOD WATCH WITH THIS UPDATE AND DROPPED POPS BACK
TO SCT/CHC CATEG FOR THE REST OF THIS EVENING.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH MONDAY NIGHT/...
EXPECT LOW CLOUDS TO PERSIST TONIGHT ACRS THE CENTRAL MTNS AND
SERN PA. LATEST HRRR SHOWS MUCH OF THE PCPN DISSIPATING BY 03Z.
HOWEVER WILL STILL HANG ONTO HIGH CHC-LOW LKLY POPS THRU 06Z IN
THE EAST.
PESKY MID-UPPER LVL CIRCULATION IN THE MID-ATLC STATES WILL BE
LIFTING NEWD FM THE DELMARVA AT THE START OF THE PD. THIS FEATURE
WILL BE ABSORBED INTO LARGE SCALE TROUGH FCST TO SHIFT SEWD FROM
THE GREAT LAKES INTO THE NORTHEAST.
WEAK RIDGING BTWN THE DEPARTING/WEAKENING UPPER LEVEL CIRCULATION
AND APPROACHING LW TROUGH SHOULD BRING DRIER AND WARMER WX TO
CENTRAL PA BY THE AFTN...WITH ANY SHOWER ACTIVITY ENDING EARLY IN
THE DAY ACROSS THE EASTERN COUNTIES. HOWEVER MAIN QUESTION IS HOW
FAST THE LOW CLOUDS WILL ERODE. WITH THE LLVL FLOW GRADUALLY
VEERING MORE THE WSW...ANTICIPATE A SLOW IMPROVEMENT WITH PEAKS OF
SUN LKLY BY THE AFTN. FOCUS FOR CONVECTION WILL SHIFT TO ELONGATED
SFC COLD FRONT ASSOC WITH THE LG SCALE TROF DIGGING INTO THE NE
STATES. BEST CHC FOR LATE AFTN TSTM WILL BE OVER THE NW MTNS WITH
POPS INCREASING INTO THE CENTRAL ZONES MON NGT.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THE COLD FRONT WILL PASS TO OUR SOUTH AND EAST LATE MONDAY NIGHT
OR EARLY TUESDAY...TAKING ANY LINGERING SHRA/TSRA WITH IT. SFC
HIGH PRESSURE SHOULD PROVIDE DRY WEATHER AND SEASONABLE TEMPS FOR
WED AND THURS.
A BUILDING RIDGE OF UPPER LEVEL HIGH PRESSURE WILL BEGIN TO WARM
THINGS UP BY FRIDAY. 12Z GEFS PUSHES 850MB TEMPS TO +1 SD BY FRI
AND KEEPS THEM THERE INTO NEXT WEEKEND.
AN ADDITIONAL CONCERN HEADING INTO NEXT WEEKEND IS THE REMNANTS
OF ISAAC. THE 12Z GEFS AND OPERATIONAL GFS BOTH TAKE WHAT IS LEFT
OF ISAAC AND CURL IT UP AND OVER THE BUILDING UPPER LEVEL RIDGE
NEXT WEEKEND....WHICH COULD TURN OUR WEATHER UNSETTLED. THE 12Z
OPERATIONAL ECMWF BRINGS THE REMNANTS OF ISAAC NORTHWARD FROM THE
GULF OF MEX INTO THE OHIO VALLEY BY THIS WEEKEND...WHERE IT
MEANDERS INTO EARLY NEXT WEEK BEFORE BEING EJECTED EASTWARD BY A
DIGGING UPPER LEVEL TROUGH.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
CONDITIONS MOSTLY VFR ACROSS CENTRAL PA AT 00Z...WITH AREA OF MVFR
CIGS IMPACTING THE SOUTH CENTRAL MTNS. REMNANTS OF EARLIER SCT
THUNDERSTORMS AND AREAS OF SHOWERS QUICKLY DIMINISHING EARLY THIS
EVENING...WITH JUST ABOUT ALL ACTIVITY EXPECTED TO BE GONE BY 01Z.
HOWEVER...SCT SHOWERS WILL LINGER INTO THE OVERNIGHT ACROSS
PORTIONS OF SOUTHERN TIER. PLENTY OF LOW LEVEL MOISTURE REMAINS IN
PLACE...FED BY ONGOING SE-S FLOW. THIS WILL ALLOW FORMATION OF AN
MVFR DECK LATE THIS EVENING...WITH CIGS/VSBYS LOWERING TO IFR IN
MOST PLACES AFTER 06Z FOR THE OVERNIGHT HOURS.
ON MON...IFR START WILL /GRADUALLY/ IMPROVE BACK TO A CLOUDY VFR BY
MID/LATE MORNING. INSTABILITY REMAINS HIGH ENOUGH FOR SCT SHOWERS
TO DEVELOP IN THE SE...WITH ADDITIONAL SCT SHOWERS ASSOCIATED WITH
AN APPROACHING COLD FRONT MOVING INTO WESTERN PORTIONS LATE IN
THE DAY.
OUTLOOK...
MON...AM LOW CIGS -SHRA EAST BCMG MVFR/VFR BY AFTN. PM SHRA/TSRA NW.
MON NGT-TUE...CFRONT PASSAGE. SHRA/TSRA POSS. MVFR-IFR LIKELY MON NIGHT.
WED-FRI...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DEVOIR/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...EVANEGO
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
723 PM EDT SUN AUG 26 2012
.SYNOPSIS...
AN UPPER LOW OVER NORTHWEST VIRGINIA THIS EVENING WILL WEAKEN AS
IT LIFTS SLOWLY TOWARD THE DELMARVA TONIGHT. THIS CIRCULATION
WILL BE ABSORBED INTO A LARGER SCALE TROUGH MOVING EASTWARD FROM
THE GREAT LAKES INTO THE NORTHEAST STATES THROUGH MONDAY NIGHT.
THE GREAT LAKES TROUGH WILL SEND A COLD FRONT ACROSS THE REGION BY
EARLY TUESDAY. HIGH PRESSURE WILL SHIFT SOUTHEAST FROM THE UPPER
MIDWEST INTO PENNSYLVANIA FOR THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
STEADIER STRATIFORM RAINFALL IS NOW DECREASING...WITH THE MOST
ORGANIZED ACTIVITY PUSHING NORTHWARD ALONG THE WEAKENED OUTFLOW
WHICH BROUGHT LOCALIZED 40-45 MPH GUSTS TO THE CENTRAL MOUNTAINS
EARLIER THIS EVENING. WINDS NOT NEARLY AS STRONG NOW...BUT WILL
SEE THE OUTFLOW PUSH NORTH OF COUDERSPORT AND MANSFIELD SHORTLY
WITH SOME 30 MPH GUSTS AND BRIEF MODERATE TO HEAVY SHOWERS.
LIGTHNING HAS DWINDLED AS WELL...SO WILL DROP TSTORM MENTIONS FOR
THE NIGHT AS WELL.
DROPPED FLASH FLOOD WATCH WITH THIS UPDATE AND DROPPED POPS BACK
TO SCT/CHC CATEG FOR THE REST OF THIS EVENING.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH MONDAY NIGHT/...
EXPECT LOW CLOUDS TO PERSIST TONIGHT ACRS THE CENTRAL MTNS AND
SERN PA. LATEST HRRR SHOWS MUCH OF THE PCPN DISSIPATING BY 03Z.
HOWEVER WILL STILL HANG ONTO HIGH CHC-LOW LKLY POPS THRU 06Z IN
THE EAST.
PESKY MID-UPPER LVL CIRCULATION IN THE MID-ATLC STATES WILL BE
LIFTING NEWD FM THE DELMARVA AT THE START OF THE PD. THIS FEATURE
WILL BE ABSORBED INTO LARGE SCALE TROUGH FCST TO SHIFT SEWD FROM
THE GREAT LAKES INTO THE NORTHEAST.
WEAK RIDGING BTWN THE DEPARTING/WEAKENING UPPER LEVEL CIRCULATION
AND APPROACHING LW TROUGH SHOULD BRING DRIER AND WARMER WX TO
CENTRAL PA BY THE AFTN...WITH ANY SHOWER ACTIVITY ENDING EARLY IN
THE DAY ACROSS THE EASTERN COUNTIES. HOWEVER MAIN QUESTION IS HOW
FAST THE LOW CLOUDS WILL ERODE. WITH THE LLVL FLOW GRADUALLY
VEERING MORE THE WSW...ANTICIPATE A SLOW IMPROVEMENT WITH PEAKS OF
SUN LKLY BY THE AFTN. FOCUS FOR CONVECTION WILL SHIFT TO ELONGATED
SFC COLD FRONT ASSOC WITH THE LG SCALE TROF DIGGING INTO THE NE
STATES. BEST CHC FOR LATE AFTN TSTM WILL BE OVER THE NW MTNS WITH
POPS INCREASING INTO THE CENTRAL ZONES MON NGT.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THE COLD FRONT WILL PASS TO OUR SOUTH AND EAST LATE MONDAY NIGHT
OR EARLY TUESDAY...TAKING ANY LINGERING SHRA/TSRA WITH IT. SFC
HIGH PRESSURE SHOULD PROVIDE DRY WEATHER AND SEASONABLE TEMPS FOR
WED AND THURS.
A BUILDING RIDGE OF UPPER LEVEL HIGH PRESSURE WILL BEGIN TO WARM
THINGS UP BY FRIDAY. 12Z GEFS PUSHES 850MB TEMPS TO +1 SD BY FRI
AND KEEPS THEM THERE INTO NEXT WEEKEND.
AN ADDITIONAL CONCERN HEADING INTO NEXT WEEKEND IS THE REMNANTS
OF ISAAC. THE 12Z GEFS AND OPERATIONAL GFS BOTH TAKE WHAT IS LEFT
OF ISAAC AND CURL IT UP AND OVER THE BUILDING UPPER LEVEL RIDGE
NEXT WEEKEND....WHICH COULD TURN OUR WEATHER UNSETTLED. THE 12Z
OPERATIONAL ECMWF BRINGS THE REMNANTS OF ISAAC NORTHWARD FROM THE
GULF OF MEX INTO THE OHIO VALLEY BY THIS WEEKEND...WHERE IT
MEANDERS INTO EARLY NEXT WEEK BEFORE BEING EJECTED EASTWARD BY A
DIGGING UPPER LEVEL TROUGH.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
GRADUAL IMPROVEMENT/BINOVC CONTINUES ACRS CNTRL PA TERMINALS WITH
MVFR TO VFR CLOUD BASES GENERALLY BTWN 2-4KFT AGL. THIS TREND
WILL CONTINUE INTO THE MID-LATE AFTN AS THE BLYR CONTINUES TO
MIX...BUT EXPECT DIURNAL COOLING/INCREASING STABILITY TO ALLOW
CIGS TO LOWER AND FILL BACK IN OVERNIGHT. TSTM DEVELOPMENT HAS
INCREASED RAPIDLY SOUTH OF THE MASON-DIXON LINE...WITH CLUSTERS/BANDS
LIFTING N-NWWD FROM NRN MD/VA INTO S-CENTRAL PA. THE HIGHEST PROB
OF SHOWERS/ISOLD TSTM WILL EXIST ACRS THE SRN AIRFIELDS. HOWEVER
CONFIDENCE/TIMING ARE STILL UNCERTAIN AND THUS WILL CONTINUE TO
MENTION VCSH IN THE SRN TERMINALS.
OUTLOOK...
MON...AM LOW CIGS -SHRA EAST BCMG MVFR/VFR BY AFTN. PM SHRA/TSRA NW.
MON NGT-TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED- THU...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DEVOIR/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...EVANEGO
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1155 PM CDT FRI AUG 24 2012
.UPDATE...REST OF TONIGHT
COLD FRONT CONTINUES TO MOVE EAST ACROSS THE REGION AND IS MOVING
THROUGH NORTH CENTRAL SD AT THIS TIME. MOST THUNDERSTORM ACTIVITY
HAS DIMINISHED AND 00Z NAM AND LATEST HRRR RUN INDICATE AREAL
COVERAGE THROUGH 12Z MAY BE LESS THAN ORIGINALLY FORECAST. HAVE
THEREFORE LOWERED POPS TO SLIGHT OR LOW CHANCE FOR THE REMAINDER
OF THE NIGHT.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
MAIN FORECAST CHALLENGE IS PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY MORNING. AS OF 19Z...A COLD FRONT WAS LOCATED OVER THE
FAR WESTERN DAKOTAS...AND WAS SLOWLY MAKING ITS WAY EASTWARD.
MODELS ARE IN GOOD AGREEMENT SHOWING THE FRONT HAVING JUST PUSHED
THROUGH THE FAR NORTHWESTERN CWA BY 06Z...THEN EXTENDING FROM
ABOUT KABR TO KPIR BY 12Z SATURDAY BEFORE PUSHING OFF TO THE EAST
OF THE CWA BY MIDDAY SATURDAY. THIS FRONT LOOKS TO BE THE FOCUS
FOR SHOWER AND THUNDERSTORM DEVELOPMENT THIS EVENING THROUGH
SATURDAY MORNING. HOWEVER...BEST UPPER LEVEL DYNAMICS WILL BE OVER
NORTH DAKOTA AS A SHORTWAVE TRACKS FROM NORTHERN MONTANA ACROSS
SOUTH CENTRAL CANADA. INSTABILITY WILL BE AT ITS BEST DURING THE
EVENING HOURS WITH CAPE VALUES OF 500-1000 J/KG AND LIS BETWEEN 0
AND -4. 0-6KM WIND SHEAR IS PRETTY WEAK OVER THE CWA THIS
EVENING...BUT DOES GET A BIT BETTER OVERNIGHT...HOWEVER THIS LOOKS
TO OCCUR POST FRONTAL. SHEAR VALUES WILL BE MUCH BETTER TO THE
NORTH. SO...THINKING THERE WILL BE SHOWERS AND THUNDERSTORMS
DURING THE EVENING AND OVERNIGHT HOURS...BUT AT THIS TIME IT LOOKS
LIKE BEST CHANCES OF SEVERE WILL BE NORTH OF THE CWA.
HOWEVER...CANNOT TOTALLY RULE OUT A STORM OR TWO BECOMING STRONG
ACROSS THE FAR NORTHERN CWA...BUT IT SHOULD BE LIMITED TO THAT
AREA. WILL LIKELY SEE SOME SHOWER ACTIVITY LINGER ACROSS THE EAST
INTO SATURDAY MORNING.
SURFACE HIGH PRESSURE SETTLES IN OVER THE REGION SATURDAY
AFTERNOON THROUGH THE DAY SUNDAY. A WARM FRONT ASSOCIATED WITH LOW
PRESSURE OVER THE NORTHERN AND CENTRAL ROCKIES WILL APPROACH THE
AREA SUNDAY NIGHT...AND MAY BRING A FEW SHOWERS OR THUNDERSTORMS
TO THE SOUTHERN CWA. WILL KEEP POPS IN THE SCHC CATEGORY FOR NOW.
COOLER AIR AND THE POTENTIAL OF MORE CLOUD COVER WITH THE POSSIBLE
PRECIPITATION WILL KEEP DAYTIME HIGHS ON SATURDAY NEAR TO SLIGHTLY
BELOW NORMAL. WILL SEE TEMPERATURES REBOUND ON SUNDAY AS WAA
REDEVELOPS WITH THE APPROACH OF THE WARM FRONT...BRINGING
AFTERNOON HIGHS BACK INTO THE MID 80S TO LOWER 90S.
.LONG TERM...MONDAY THROUGH FRIDAY
MEDIUM TO LONG RANGE MODELS CONTINUE TO ADVERTISE SIMILAR LONG
WAVE PATTERN NEXT WEEK. MID LVL RIDGE OF HIGH PRESSURE WILL BE
POISED OVER THE CENTRAL ROCKIES AND CENTRAL PLAINS WITH THE RIDGE
AXIS EXTENDING INTO THE NORTHERN HIGH PLAINS. GUIDANCE PROGS THIS
TO GRADUALLY BUILD AND SLIDE EWD ACROSS THE MID SECTION OF THE
COUNTRY TOWARD THE MIDDLE OF NEXT WEEK. AS THIS FEATURE BECOMES THE
MORE DOMINANT WEATHER MAKER EARLY IN THE PERIOD...CONDITIONS ARE
LIKELY TO REMAIN DRY. CAN`T RULE OUT SOME POP UP CONVECTION EARLY
IN THE PERIOD...IF A WEAK WAVE MOVES THRU...BUT CONFIDENCE IS TOO
LOW IN PCPN CHANCES AND PLACEMENT TO INCLUDE IN THE FORECAST.
LOCALLY...HEIGHT RISES DURING THE FIRST HALF OF THE WEEK WILL
TRANSLATE INTO RATHER HOT TEMPERATURES FOR LATE AUGUST. AN UPPER
TROUGH WILL CRASH INTO THE PACIFIC NORTHWEST TOWARD THE MIDDLE OF
THE WEEK AND THEN POTENTIALLY INTO OUR REGION BY THE END OF THE
PERIOD. HOWEVER...INCONSISTENCIES STILL EXIST WITH THIS FEATURE
AMONG THE LONG RANGE GUIDANCE SO HAVE KEPT THE FORECAST DRY AND
COOLED TEMPS JUST A BIT LATE IN THE PERIOD.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A COLD FRONT WILL SWEEP ACROSS THE CWA OVERNIGHT. WINDS WILL SHIFT
TO THE NORTHWEST BEHIND THE FRONT. VFR CONDITIONS ARE EXPECTED
THROUGH SATURDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...PARKIN
LONG TERM...VIPOND
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
128 PM CDT SAT AUG 25 2012
.UPDATE...
18Z TAF UPDATE BELOW.
&&
.AVIATION...
PERIODS OF SCATTERED SHOWERS...WITH ISOLATED CELLS TRANSITIONING
TO THUNDERSTORMS...WITH A MORE MODERATE ONSHORE WIND OF BETWEEN
15-20 MPH THROUGH THE AFTERNOON. MOST OF THE TSRA ACTIVITY WILL
BE CONFINED TO THE CENTRAL FORECAST AREA (HOUSTON) SOUTHWARD...WITH
ANY PASSING CLUSTER NOT PERSISTING FOR MORE THAN 15 OR 20 MINUTES.
LOCALLY GUSTY WINDS TO 20 MPH AND REDUCED VISBIES TO AROUND 2 SM
WITHIN THE STRONGEST STORMS. CLEARING OUT SHORTLY AFTER SUNSET
WITH HIGH MOISTURE VALUES LEADING TO 06-12Z PERIODS OF MVFR DECKS
OVER NON-METRO HUBS. LESS OVERALL PRECIPITATION TOMORROW...MORE
WIDELY SCATTERED CELLS THAT WILL KEEP THE MENTION OF TSRA (OR
SHRA) OUT OF SUNDAY`S TAF. 31
&&
.PREV DISCUSSION... /ISSUED 1043 AM CDT SAT AUG 25 2012/
UPDATE...
SEE MORNING UPDATE.
DISCUSSION...
12Z SOUNDINGS SHOWED PW VALUES BETWEEN 1.9 INCHES SOUTHWEST TO
2.30 INCHES OVER THE EXTREME EAST. CONVECTIVE TEMPS ARE BETWEEN 83
DEGREES OVER THE EAST AND AROUND 88 DEGREES SOUTHWEST. 250 MB
WINDS REMAIN DIVERGENT SO FEEL PARAMETERS ARE IN PLACE FOR A
DECENT CHANCE OF SHRA/TSRA TODAY. TEMPS AT 10 AM ARE ALREADY IN
THE MID AND UPPER 80S SO FEEL COVERAGE WILL BEGIN TO FILL IN. THE
LATEST RAP MODEL SHOWS PRECIP EXPANDING INTO THE NORTHWEST ZONES
LATE THIS AFTN AND AM TEMPTED TO BOOST POPS BUT WILL WATCH TRENDS
BEFORE MAKING THAT CALL. REST OF FCST LOOKS ON TRACK. 43
&&
PREV DISCUSSION... /ISSUED 626 AM CDT SAT AUG 25 2012/
AVIATION...
SCATTERED SHOWERS OFFSHORE CONTINUE TO APPROACH THE COAST WHILE
ADDITIONAL SHOWERS ARE FINALLY BEGINNING TO DEVELOP INLAND NEAR
GALVESTON BAY. FURTHER NORTH...AM A BIT CONCERNED THAT VSBYS FOR
CXO WILL DROP SHARPLY OVER THE FIRST HOUR OF THE TAF PERIOD AS
SKIES CLEAR AND WINDS HAVE BECOME CALM. OTHERWISE VFR CONDITIONS
SHOULD PREVAIL THROUGH THE TAF PERIOD WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON HOURS TODAY.
COVERAGE SHOULD BE A BIT LESS THAN YESTERDAY AND CONFINED MAINLY
TO THE EASTERN TWO THIRDS OF THE CWA...THUS WILL NOT CARRY A
MENTION OF VCTS FOR CLL THIS AFTERNOON. WINDS OVERNIGHT INTO
SUNDAY SHOULD BE LOWER THAN TONIGHT AS THE PRESSURE GRADIENT
BEGINS TO RELAX ACROSS THE REGION. 38
PREV DISCUSSION... /ISSUED 430 AM CDT SAT AUG 25 2012/
DISCUSSION...
IR SATELLITE LESS CLOUDY AND RADAR LOOPS LESS ACTIVE THIS MORNING
BUT A FEW SHRA ARE NOTED OVER THE WATER AND OVER JACKSON AND
SOUTHWESTERN MATAGORDA COUNTIES AT 09Z. 00Z 250MB MANUAL ANALYSIS
INDICATES HIGH PRESSURE OVER BAJA CA RIDGING TO THE NW OVER
TX...BELOW AT 500MB VERY WEAK TROUGH NOTED FROM KHGX TO KBRO. FROM
SFC-700MB RIDGE AXIS FROM ATLANTIC SUBTROPICAL HIGH IS IN PLACE
WITH SE TX ON THE FRINGE OF THE CIRCULATION. PWAT GRADIENT RUNS
FROM 1.6 IN WESTERN PART OF FA TO NEAR 2 INCHES EAST OF GLS BAY.
GFS FORECASTS ONSHORE FLOW TODAY WITH A GENERAL INCREASE IN PWATS.
HAVE FINE TUNED PCPN CHANCES TODAY FROM PREVIOUS FORECAST WITH
HIGHER CHANCES AGAIN TO THE SOUTHEAST IN GALVESTON AND CHAMBERS
COUNTIES AND OFFSHORE WATERS. NOT EXPECTING AVERAGE RAINFALL
AMOUNTS TO BE AS HIGH AS YESTERDAY WITH GREATEST AMOUNTS IN THE
SOUTHEAST...PERHAPS AVERAGING 0.25 TO 0.50 INCH LOCALLY. GIVEN
KCLL REACHING 95 YESTERDAY MAX TEMPS IN THE NORTHWEST WERE RAISED
SLIGHTLY TODAY.
TOMORROW MEAN SFC-700MB RIDGING MOVES NORTH TAPERING OFF THE
MOISTURE TAP. GFS SPLITS A PIECE OF THE UPPER TROUGH NOW OVER THE
TX PANHANDLE TO OUR WEST TOMORROW SO CANNOT RULE OUT PCPN CHANCES
BUT THEY ARE LOWER THAN TODAY. BY MONDAY ISAAC IS FORECAST BY NHC
TO BE IN THE FAR EASTERN GULF. THIS PUTS SE TX IN A GENERALLY DEEP
OFFSHORE FLOW REGIME. INTERESTING FLIES IN THE OINTMENT FOR
TUESDAY IS A WESTERLY MOVING 250MB LOW THAT BREAKS OFF THE TROUGH
NOW IN THE SOUTHEASTERN US AND SOME RELATIVELY HIGH PWAT AIR ALONG
AND AHEAD OF A FRONTAL ZONE TO OUR NORTH. ECM/GFS MOS POPS ARE
QUITE HIGH ON TUESDAY (40 TO NEAR 50 PERCENT) BUT GIVEN THE USUAL
PATTERN OFF TO THE NORTHWEST OF TROPICAL SYSTEMS IN THE GULF THIS
PCPN CHANCE SEEMS HIGH SO WILL COMPROMISE BY LEAVING OUR 20
PERCENT FORECAST IN PLACE. WILL NEED TO CONTINUE TO MONITOR THIS
AS TUESDAY COULD BE BRIEFLY WETTER. WED THOUGH THE NEXT WEEKEND
LOOK VERY DRY AND TEMPERATURES WILL BE WARMING. GFS ENSEMBLE MEAN
MOS IS HIGHER THAN GFS LONG RANGE MOS (MEX) AND THE EXPERIMENTAL
ECM MOS IS EVEN HIGHER. AS A RESULT MAX TEMPS ON THU-FRI WERE
INCREASED.
CORRECTED FOR GRAMMAR. 04
MARINE...
SURFACE PRESSURE GRADIENT REMAINS RATHER TIGHT ACROSS EASTERN TEXAS
AND LOUISIANA THIS MORNING KEEPING WINDS ACROSS THE COASTAL WATERS
AT AROUND 15KTS...THUS WILL KEEP THE CURRENT ADVISORY FLAGS IN PLACE
THROUGH MIDDAY. WINDS SHOULD BEGIN TO EASE ON SUNDAY BEFORE BECOMING
OFFSHORE BY TUESDAY IN RESPONSE TO ISAAC MOVING INTO THE EASTERN
GULF OF MEXICO. AT THIS TIME IT APPEARS THAT ISAAC WILL REMAIN WELL
TO THE EAST OF OUR AREA WITH MARITIME IMPACTS TO THE UPPER TEXAS
COAST LIMITED TO 3 TO 4 FOOT SEAS ACROSS THE OFFSHORE WATERS AND
SLIGHTLY BELOW NORMAL TIDE LEVELS DUE TO NORTHERLY WINDS OF AROUND
10 TO 15 KTS.
ALTHOUGH ISAAC IS NOT FORECAST TO DIRECTLY AFFECT THE UPPER TEXAS
COASTAL WATERS MARINERS ARE URGED TO CONTINUE MONITORING NHC
FORECASTS AND ADVISORIES REGARDING THE SYSTEM AS IT MOVES INTO THE
GULF OF MEXICO EARLY NEXT WEEK. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 75 95 76 / 20 20 10 20 20
HOUSTON (IAH) 76 93 75 94 75 / 20 30 10 30 20
GALVESTON (GLS) 79 90 80 91 81 / 20 30 10 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1043 AM CDT SAT AUG 25 2012
.UPDATE...
SEE MORNING UPDATE.
&&
.DISCUSSION...
12Z SOUNDINGS SHOWED PW VALUES BETWEEN 1.9 INCHES SOUTHWEST TO
2.30 INCHES OVER THE EXTREME EAST. CONVECTIVE TEMPS ARE BETWEEN 83
DEGREES OVER THE EAST AND AROUND 88 DEGREES SOUTHWEST. 250 MB
WINDS REMAIN DIVERGENT SO FEEL PARAMETERS ARE IN PLACE FOR A
DECENT CHANCE OF SHRA/TSRA TODAY. TEMPS AT 10 AM ARE ALREADY IN
THE MID AND UPPER 80S SO FEL COVERAGE WILL BEGIN TO FILL IN. THE
LATEST RAP MODEL SHOWS PRECIP EXPANDING INTO THE NORTHWEST ZONES
LATE THIS AFTN AND AM TEMPTED TO BOOST POPS BUT WILL WATCH TRENDS
BEFORE MAKING THAT CALL. REST OF FCST LOOKS ON TRACK. 43
&&
.PREV DISCUSSION... /ISSUED 626 AM CDT SAT AUG 25 2012/
AVIATION...
SCATTERED SHOWERS OFFSHORE CONTINUE TO APPROACH THE COAST WHILE
ADDITIONAL SHOWERS ARE FINALLY BEGINNING TO DEVELOP INLAND NEAR
GALVESTON BAY. FURTHER NORTH...AM A BIT CONCERNED THAT VSBYS FOR
CXO WILL DROP SHARPLY OVER THE FIRST HOUR OF THE TAF PERIOD AS
SKIES CLEAR AND WINDS HAVE BECOME CALM. OTHERWISE VFR CONDITIONS
SHOULD PREVAIL THROUGH THE TAF PERIOD WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON HOURS TODAY.
COVERAGE SHOULD BE A BIT LESS THAN YESTERDAY AND CONFINED MAINLY
TO THE EASTERN TWO THIRDS OF THE CWA...THUS WILL NOT CARRY A
MENTION OF VCTS FOR CLL THIS AFTERNOON. WINDS OVERNIGHT INTO
SUNDAY SHOULD BE LOWER THAN TONIGHT AS THE PRESSURE GRADIENT
BEGINS TO RELAX ACROSS THE REGION. 38
PREV DISCUSSION... /ISSUED 430 AM CDT SAT AUG 25 2012/
DISCUSSION...
IR SATELLITE LESS CLOUDY AND RADAR LOOPS LESS ACTIVE THIS MORNING
BUT A FEW SHRA ARE NOTED OVER THE WATER AND OVER JACKSON AND
SOUTHWESTERN MATAGORDA COUNTIES AT 09Z. 00Z 250MB MANUAL ANALYSIS
INDICATES HIGH PRESSURE OVER BAJA CA RIDGING TO THE NW OVER
TX...BELOW AT 500MB VERY WEAK TROUGH NOTED FROM KHGX TO KBRO. FROM
SFC-700MB RIDGE AXIS FROM ATLANTIC SUBTROPICAL HIGH IS IN PLACE
WITH SE TX ON THE FRINGE OF THE CIRCULATION. PWAT GRADIENT RUNS
FROM 1.6 IN WESTERN PART OF FA TO NEAR 2 INCHES EAST OF GLS BAY.
GFS FORECASTS ONSHORE FLOW TODAY WITH A GENERAL INCREASE IN PWATS.
HAVE FINE TUNED PCPN CHANCES TODAY FROM PREVIOUS FORECAST WITH
HIGHER CHANCES AGAIN TO THE SOUTHEAST IN GALVESTON AND CHAMBERS
COUNTIES AND OFFSHORE WATERS. NOT EXPECTING AVERAGE RAINFALL
AMOUNTS TO BE AS HIGH AS YESTERDAY WITH GREATEST AMOUNTS IN THE
SOUTHEAST...PERHAPS AVERAGING 0.25 TO 0.50 INCH LOCALLY. GIVEN
KCLL REACHING 95 YESTERDAY MAX TEMPS IN THE NORTHWEST WERE RAISED
SLIGHTLY TODAY.
TOMORROW MEAN SFC-700MB RIDGING MOVES NORTH TAPERING OFF THE
MOISTURE TAP. GFS SPLITS A PIECE OF THE UPPER TROUGH NOW OVER THE
TX PANHANDLE TO OUR WEST TOMORROW SO CANNOT RULE OUT PCPN CHANCES
BUT THEY ARE LOWER THAN TODAY. BY MONDAY ISAAC IS FORECAST BY NHC
TO BE IN THE FAR EASTERN GULF. THIS PUTS SE TX IN A GENERALLY DEEP
OFFSHORE FLOW REGIME. INTERESTING FLIES IN THE OINTMENT FOR
TUESDAY IS A WESTERLY MOVING 250MB LOW THAT BREAKS OFF THE TROUGH
NOW IN THE SOUTHEASTERN US AND SOME RELATIVELY HIGH PWAT AIR ALONG
AND AHEAD OF A FRONTAL ZONE TO OUR NORTH. ECM/GFS MOS POPS ARE
QUITE HIGH ON TUESDAY (40 TO NEAR 50 PERCENT) BUT GIVEN THE USUAL
PATTERN OFF TO THE NORTHWEST OF TROPICAL SYSTEMS IN THE GULF THIS
PCPN CHANCE SEEMS HIGH SO WILL COMPROMISE BY LEAVING OUR 20
PERCENT FORECAST IN PLACE. WILL NEED TO CONTINUE TO MONITOR THIS
AS TUESDAY COULD BE BRIEFLY WETTER. WED THOUGH THE NEXT WEEKEND
LOOK VERY DRY AND TEMPERATURES WILL BE WARMING. GFS ENSEMBLE MEAN
MOS IS HIGHER THAN GFS LONG RANGE MOS (MEX) AND THE EXPERIMENTAL
ECM MOS IS EVEN HIGHER. AS A RESULT MAX TEMPS ON THU-FRI WERE
INCREASED.
CORRECTED FOR GRAMMAR. 04
MARINE...
SURFACE PRESSURE GRADIENT REMAINS RATHER TIGHT ACROSS EASTERN TEXAS
AND LOUISIANA THIS MORNING KEEPING WINDS ACROSS THE COASTAL WATERS
AT AROUND 15KTS...THUS WILL KEEP THE CURRENT ADVISORY FLAGS IN PLACE
THROUGH MIDDAY. WINDS SHOULD BEGIN TO EASE ON SUNDAY BEFORE BECOMING
OFFSHORE BY TUESDAY IN RESPONSE TO ISAAC MOVING INTO THE EASTERN
GULF OF MEXICO. AT THIS TIME IT APPEARS THAT ISAAC WILL REMAIN WELL
TO THE EAST OF OUR AREA WITH MARITIME IMPACTS TO THE UPPER TEXAS
COAST LIMITED TO 3 TO 4 FOOT SEAS ACROSS THE OFFSHORE WATERS AND
SLIGHTLY BELOW NORMAL TIDE LEVELS DUE TO NORTHERLY WINDS OF AROUND
10 TO 15 KTS.
ALTHOUGH ISAAC IS NOT FORECAST TO DIRECTLY AFFECT THE UPPER TEXAS
COASTAL WATERS MARINERS ARE URGED TO CONTINUE MONITORING NHC
FORECASTS AND ADVISORIES REGARDING THE SYSTEM AS IT MOVES INTO THE
GULF OF MEXICO EARLY NEXT WEEK. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 93 75 94 75 95 / 20 20 20 10 20
HOUSTON (IAH) 91 76 93 75 94 / 40 20 30 10 30
GALVESTON (GLS) 88 79 90 80 91 / 50 20 30 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1023 PM CDT SUN AUG 26 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
227 PM CDT SUN AUG 26 2012
DRY CONDITIONS EXPECTED THROUGH MID WEEK WITH THE MAIN FORECAST
FOCUS BEING ON TEMPERATURES AND FOG.
CURRENTLY...A SYSTEM THAT BROUGHT RAIN AND CLOUD COVER TO THE
REGION TODAY IS SLOWLY RETREATING EAST INTO THE GREAT LAKES. RAIN
HAS COME TO AN END WITH THE UPPER LEVEL TROUGH PUSHING INTO EASTERN
WISCONSIN. THE QUESTION FOR TONIGHT IS WITH HOW FAST THE CLOUDS
CLEAR OUT AND WHETHER ANY FOG WILL DEVELOP AS IT DID ACROSS
WESTERN MINNESOTA/IOWA THIS MORNING. THE 26.18Z RAP MOISTURE
FIELDS SHOW THE DEEPER MOISTURE FIELD ASSOCIATED WITH THE TROUGH
AND RAINFALL SHIFTING EAST BY THIS EVENING. ALSO...THE STRATUS
FIELD ALONG THE WESTERN SIDE OF THE TROUGH HAS BECOME MUCH MORE
CELLULAR AND SHOULD THIN OUT THIS EVENING AND LEAD TO CLEAR SKIES
THOUGH OUT THE REGION OVERNIGHT.
WITH THESE CLEARING SKIES...LIGHT WINDS...AND A RIDGE AXIS OF
HIGH PRESSURE PUSHING IN...WILL LIKELY SEE SOME FOG FORM ACROSS
THE REGION. THE BEST CHANCES FOR WIDESPREAD AND POSSIBLY DENSE FOG
WILL BE ACROSS SOUTHERN WISCONSIN INTO EASTERN IOWA WHERE THE RAIN
AND CLOUDS HOLD ON LONGER TODAY BEFORE CLEARING OUT LATER TONIGHT.
SHOULD ALSO SEE FOG FORM IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS TONIGHT AS WELL THOUGH HOW WIDESPREAD IT BECOMES WILL BE
DEPENDENT UPON THE LOW LEVEL WIND FIELDS. SEE THE LATEST AVIATION
AFD FOR FURTHER/UPDATED DETAILS ON THE POTENTIAL FOR THIS VALLEY
FOG.
GOING INTO THE EARLY TO MID PORTIONS OF THE WEEK...WARMER AIR WILL
SLOWLY ADVECT INTO THE REGION FROM THE WEST AS A SURFACE RIDGE OF
HIGH PRESSURE SETTLES OVER THE UPPER MISSISSIPPI RIVER VALLEY AND
AN UPPER LEVEL RIDGE BUILDS ACROSS THE ROCKIES. WILL HAVE TO WATCH
A WARM FRONT THAT SURGES NORTHWARD TUESDAY INTO WEDNESDAY AS THE
26.12Z NAM AND GFS TRY TO PRODUCE SOME ELEVATED CONVECTION ACROSS
MINNESOTA WESTERN WISCONSIN. CONFIDENCE IS NOT HIGH THAT THIS
CONVECTION WILL OCCUR GIVEN THE DRY LOW LEVELS AND BETTER MOISTURE
TRANSPORT OFF TO THE WEST...SO HAVE KEPT THE FORECAST DRY THROUGH
THIS PERIOD BUT HAVE PUT SOME SLIGHTLY HIGHER CLOUD COVER IN OVER
THIS TIME FRAME. OTHERWISE EXPECT TEMPERATURES TO SLOWLY REBOUND
GOING INTO MID WEEK AS WARMER AIR SPILLS TO THE EAST AS THE
WESTERN RIDGE BUILDS EASTWARD INTO THE REGION WITH 850MB
TEMPERATURES CLIMBING FROM AROUND +13C ON MONDAY TO AROUND +23C BY
WEDNESDAY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
227 PM CDT SUN AUG 26 2012
THE MAIN STORY FOR THE LATER PART OF THE WEEK WITH WITH THE WARM
AIR MASS THAT WILL TAKE OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. AFTER THE WARM FRONT LIFTS NORTH OF THE REGION ON
WEDNESDAY...STRONG SOUTHERLY LOW LEVEL FLOW WILL KICK IN FROM THE
SOUTHERN PLAINS UP INTO THE GREAT LAKES AND NORTHERN PLAINS. THE
BUILDING RIDGE ACROSS THE ROCKIES WILL BEGIN TO SHIFT TO THE EAST
WEDNESDAY NIGHT INTO THURSDAY WITH THURSDAY LOOKING LIKE THE
WARMEST DAY OF THE WEEK. 850MB TEMPERATURE ANOMALIES FROM THE
26.12Z GFS AND ECMWF SHOW THAT THE +23C 850MB TEMPERATURES ARE
ABOUT 2 STANDARD DEVIATIONS ABOVE THE NORM...WHICH WOULD PUSH
RECORD HIGHS IN THE MID 90S. WITH THE WARMER AIR GRADUALLY
GETTING INTO THE REGION...HAVE GONE WITH A GRADUAL WARMING TREND
WITH THE NEAR RECORD HIGHS FOR THURSDAY. PRECIPITATION CHANCES
WILL BE MINIMAL UNTIL MAYBE NEXT WEEKEND AS A COLD FRONT DROPS
DOWN THROUGH LAKE SUPERIOR. THE 26.12Z GFS IS MORE PROGRESSIVE
WITH BRINGING THE FRONT SOUTH THROUGH THE REGION WHILE THE 26.12Z
ECMWF KEEPS THE FRONT TO THE NORTH. THE 26.12Z GFS IS ALSO ON THE
WESTERN TRACK WITH THE REMNANTS OF ISAAC COMING NORTH ALONG THE
MISSISSIPPI WHILE THE 26.12Z KEEPS IT WELL TO THE SOUTHEAST.
CONFIDENCE IS NOT VERY HIGH WITH WHERE THIS FEATURE WILL
TRACK...BUT THERE IS A BETTER CHANCE THAT IT WILL STAY TO THE
SOUTHEAST AND NOT COME INTO THE REGION. THEREFORE...HAVE KEPT THE
FORECAST MAINLY DRY THROUGH NEXT WEEKEND.
&&
.AVIATION...THROUGH MONDAY
1023 PM CDT SUN AUG 26 2012
RADIATION GROUND FOG HAS DEVELOPED AT KLSE...DUE TO LIGHT WINDS
AND LINGERING HIGH SURFACE DEWPOINTS. HAVE UPDATED THE KLSE TAF
WITH THE IDEA OF VISIBILITIES HOVERING BETWEEN IFR AND VLIFR
UNTIL 08Z...IN THE EVENT THE FOG SHIFTS AROUND NEAR THE AIRPORT.
KEPT ANY CEILINGS VFR GIVEN VERY SHALLOW NATURE OF THE FOG. AFTER
08Z AT KLSE...FORECAST REMAINS PROBLEMATIC...AS A TROUGH OF LOW
PRESSURE NEAR MINNEAPOLIS MOVES THROUGH THE SITE. IN THE WAKE OF
THE TROUGH...NORTHWEST WINDS PICK UP...LIGHTLY AT THE SURFACE BUT
10-15 KT AT 0.5-1 KM ABOVE THE GROUND. THESE WINDS ARE FORECAST TO
BRING DRIER AIR INTO THE TAF SITE THE COMBINATION OF THE WIND AND
DRIER AIR COULD EASILY REMOVE THE RADIATION FOG. ON THE OTHER
HAND...IF THE WIND DOES NOT DEVELOP...THICK VALLEY FOG WILL OCCUR
WITH VISIBILITIES AND CEILINGS BEING HELD AT VLIFR AT LEAST UNTIL
13Z. ANTICIPATING THE MORE OPTOMISTIC SCENARIO TO OCCUR...SO HAVE
VISIBILITIES CLIMBING TO MVFR FOR 08-14Z. STILL KEPT THE SCATTERED
LIFR DECK SHOULD SOME VALLEY FOG TRY TO FORM. ANY FOG OR STRATUS
WILL DISSIPATE AROUND 14Z...WITH PLENTY OF DRY AIR AROUND TO
MAINTAIN VFR CONDITIONS THROUGH THE REST OF THE DAY.
AT KRST...A STEADY 4-6 KT NORTHWEST BREEZE GRADUALLY BRINGING IN
DRIER AIR WILL KEEP VFR CONDITIONS THERE THROUGH MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
227 PM CDT SUN AUG 26 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 PM CDT SUN AUG 26 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
227 PM CDT SUN AUG 26 2012
DRY CONDITIONS EXPECTED THROUGH MID WEEK WITH THE MAIN FORECAST
FOCUS BEING ON TEMPERATURES AND FOG.
CURRENTLY...A SYSTEM THAT BROUGHT RAIN AND CLOUD COVER TO THE
REGION TODAY IS SLOWLY RETREATING EAST INTO THE GREAT LAKES. RAIN
HAS COME TO AN END WITH THE UPPER LEVEL TROUGH PUSHING INTO EASTERN
WISCONSIN. THE QUESTION FOR TONIGHT IS WITH HOW FAST THE CLOUDS
CLEAR OUT AND WHETHER ANY FOG WILL DEVELOP AS IT DID ACROSS
WESTERN MINNESOTA/IOWA THIS MORNING. THE 26.18Z RAP MOISTURE
FIELDS SHOW THE DEEPER MOISTURE FIELD ASSOCIATED WITH THE TROUGH
AND RAINFALL SHIFTING EAST BY THIS EVENING. ALSO...THE STRATUS
FIELD ALONG THE WESTERN SIDE OF THE TROUGH HAS BECOME MUCH MORE
CELLULAR AND SHOULD THIN OUT THIS EVENING AND LEAD TO CLEAR SKIES
THOUGH OUT THE REGION OVERNIGHT.
WITH THESE CLEARING SKIES...LIGHT WINDS...AND A RIDGE AXIS OF
HIGH PRESSURE PUSHING IN...WILL LIKELY SEE SOME FOG FORM ACROSS
THE REGION. THE BEST CHANCES FOR WIDESPREAD AND POSSIBLY DENSE FOG
WILL BE ACROSS SOUTHERN WISCONSIN INTO EASTERN IOWA WHERE THE RAIN
AND CLOUDS HOLD ON LONGER TODAY BEFORE CLEARING OUT LATER TONIGHT.
SHOULD ALSO SEE FOG FORM IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS TONIGHT AS WELL THOUGH HOW WIDESPREAD IT BECOMES WILL BE
DEPENDENT UPON THE LOW LEVEL WIND FIELDS. SEE THE LATEST AVIATION
AFD FOR FURTHER/UPDATED DETAILS ON THE POTENTIAL FOR THIS VALLEY
FOG.
GOING INTO THE EARLY TO MID PORTIONS OF THE WEEK...WARMER AIR WILL
SLOWLY ADVECT INTO THE REGION FROM THE WEST AS A SURFACE RIDGE OF
HIGH PRESSURE SETTLES OVER THE UPPER MISSISSIPPI RIVER VALLEY AND
AN UPPER LEVEL RIDGE BUILDS ACROSS THE ROCKIES. WILL HAVE TO WATCH
A WARM FRONT THAT SURGES NORTHWARD TUESDAY INTO WEDNESDAY AS THE
26.12Z NAM AND GFS TRY TO PRODUCE SOME ELEVATED CONVECTION ACROSS
MINNESOTA WESTERN WISCONSIN. CONFIDENCE IS NOT HIGH THAT THIS
CONVECTION WILL OCCUR GIVEN THE DRY LOW LEVELS AND BETTER MOISTURE
TRANSPORT OFF TO THE WEST...SO HAVE KEPT THE FORECAST DRY THROUGH
THIS PERIOD BUT HAVE PUT SOME SLIGHTLY HIGHER CLOUD COVER IN OVER
THIS TIME FRAME. OTHERWISE EXPECT TEMPERATURES TO SLOWLY REBOUND
GOING INTO MID WEEK AS WARMER AIR SPILLS TO THE EAST AS THE
WESTERN RIDGE BUILDS EASTWARD INTO THE REGION WITH 850MB
TEMPERATURES CLIMBING FROM AROUND +13C ON MONDAY TO AROUND +23C BY
WEDNESDAY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
227 PM CDT SUN AUG 26 2012
THE MAIN STORY FOR THE LATER PART OF THE WEEK WITH WITH THE WARM
AIR MASS THAT WILL TAKE OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. AFTER THE WARM FRONT LIFTS NORTH OF THE REGION ON
WEDNESDAY...STRONG SOUTHERLY LOW LEVEL FLOW WILL KICK IN FROM THE
SOUTHERN PLAINS UP INTO THE GREAT LAKES AND NORTHERN PLAINS. THE
BUILDING RIDGE ACROSS THE ROCKIES WILL BEGIN TO SHIFT TO THE EAST
WEDNESDAY NIGHT INTO THURSDAY WITH THURSDAY LOOKING LIKE THE
WARMEST DAY OF THE WEEK. 850MB TEMPERATURE ANOMALIES FROM THE
26.12Z GFS AND ECMWF SHOW THAT THE +23C 850MB TEMPERATURES ARE
ABOUT 2 STANDARD DEVIATIONS ABOVE THE NORM...WHICH WOULD PUSH
RECORD HIGHS IN THE MID 90S. WITH THE WARMER AIR GRADUALLY
GETTING INTO THE REGION...HAVE GONE WITH A GRADUAL WARMING TREND
WITH THE NEAR RECORD HIGHS FOR THURSDAY. PRECIPITATION CHANCES
WILL BE MINIMAL UNTIL MAYBE NEXT WEEKEND AS A COLD FRONT DROPS
DOWN THROUGH LAKE SUPERIOR. THE 26.12Z GFS IS MORE PROGRESSIVE
WITH BRINGING THE FRONT SOUTH THROUGH THE REGION WHILE THE 26.12Z
ECMWF KEEPS THE FRONT TO THE NORTH. THE 26.12Z GFS IS ALSO ON THE
WESTERN TRACK WITH THE REMNANTS OF ISAAC COMING NORTH ALONG THE
MISSISSIPPI WHILE THE 26.12Z KEEPS IT WELL TO THE SOUTHEAST.
CONFIDENCE IS NOT VERY HIGH WITH WHERE THIS FEATURE WILL
TRACK...BUT THERE IS A BETTER CHANCE THAT IT WILL STAY TO THE
SOUTHEAST AND NOT COME INTO THE REGION. THEREFORE...HAVE KEPT THE
FORECAST MAINLY DRY THROUGH NEXT WEEKEND.
&&
.AVIATION...TONIGHT AND MONDAY
618 PM CDT SUN AUG 26 2012
FOCUS REMAINS ON POTENTIAL FOR VALLEY FOG AT KLSE WHICH REMAINS
UNCERTAIN. DRIER AIR ALOFT FROM THE DAKOTAS HAS ALLOWED SKIES TO
CLEAR AT BOTH TAF SITES. THIS DRIER AIR ALOFT WILL STAY IN PLACE
THROUGH MONDAY...KEEPING SKIES CLEAR. THE CLEAR SKIES AND RECENT
RAINFALL AS WELL AS HIGH SURFACE DEWPOINTS AT THE MOMENT POSE A
THREAT FOR VALLEY FOG. THERE ARE TWO PROBLEMS THAT KEEP THIS FROM
BEING A CLEAR-CUT CASE FOR FOG: 1. DRIER SURFACE AIR OVER CENTRAL
MINNESOTA MOVING SOUTHEAST AND 2. A TROUGH EXTENDING FROM DULUTH
TO WEST-CENTRAL MINNESOTA WHICH MODELS DROP SOUTH INTO KLSE AROUND
09Z. ACCOMPANYING THAT TROUGH IS A SURGE OF 10-15 KT NORTHWEST
WINDS IN THE 0.5-1KM LAYER. ALTHOUGH NORTHWEST WINDS ALOFT ARE A
FAVORABLE DIRECTION FOR VALLEY FOG PER RESEARCH...THESE WINDS ARE
A BIT STRONG. IN FACT...IT IS POSSIBLE SURFACE WINDS END UP
NORTHWEST AROUND 5 KT...WHICH IS NOT FAVORABLE. THE NORTHWEST
WINDS WILL ALSO BRING IN DRY AIR...COUNTERACTING SOME OF THE
EVAPOTRANSPIRATION THIS EVENING. DUE TO THE UNCERTAINTIES...HAVE
MAINTAINED THE PREVIOUS FORECAST OF POTENTIAL FOR SOME FOG IN THE
VICINITY OF KLSE...AS WELL AS SOME SCATTERED LIFR STRATUS...
BETWEEN 08-14Z. WILL BE WATCHING THE SURFACE MOISTURE AND WIND
TRENDS THROUGH THE EVENING TO SEE IF VALLEY FOG LOOKS MORE LIKELY.
NO FOG EXPECTED AT KRST WITH DRIER AIR MOVING IN THERE AND A
STEADY 4-7KT NORTHWEST BREEZE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
227 PM CDT SUN AUG 26 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1125 PM MDT SUN AUG 26 2012
.AVIATION...
VFR CONDITIONS WITH LIGHT DIURNAL WINDS ARE EXPECTED OVERNIGHT AND
THROUGH TOMORROW MORNING ACROSS THE FORECAST AREA...AND FOR THE 3
TAF SITES OF KCOS...KPUB AND KALS. ISOLATED CONVECTION MAY OCCUR
AT KCOS TOMORROW AFTERNOON/EARLY EVENING SO MENTIONED VCTS
THERE...AS WELL AS KALS BUT MORE SO OVER THE HIGHER TERRAIN ALONG
THE VALLEY EDGES. TOO LOW OF A PROBABILITY FOR MENTION AT KPUB.
&&
.PREV DISCUSSION... /ISSUED 245 PM MDT SUN AUG 26 2012/
SHORT TERM...
(TONIGHT AND MONDAY)
AN UPR RIDGE WL REMAIN CENTERED OVR SRN CO AND NRN NM THROUGH MON.
SHOWERS AND THUNDERSTORMS WILL CONTINUE OVR THE HIGHER TERRAIN THRU
THE EVENING HOURS...BUT ARE EXPECTED TO DIE OFF BY MIDNIGHT. THE NAM
RAP13 AND HRRR SHOW OF A LINE OF CONVECTION DEVELOPING OVR THE
EASTERN CO PLAINS LATER THIS AFTERNOON WHICH MOVES EASTWARD INTO
EARLY EVENING. SATELLITE AND RADAR ARE SHOWING A LINE OF SOME
CONVECTION ALONG A WEAK BOUNDARY THAT EXTENDS FROM NE CO AND
SOUTHWESTWARD WHICH HAS PRODUCED SOME THUNDERSTORMS IN NERN EL PASO
COUNTY. THE MODELS HAVE THE RIGHT IDEA...BUT NOT SURE HOW FAR
SOUTHWARD THE CONVECTION WL DEVELOP. WL GO WITH SOME ISOLD POPS OVR
AT LEAST NORTHERN PORTION OF THE SOUTHEAST PLAINS EARLY THIS EVENING.
ON MONDAY THERE WILL STILL BE SOME RESIDUAL MOISTURE UNDER THE RIDGE
OVR THE AREA...AND ISOLD TO SCT SHOWERS AND TSTMS ARE AGAIN EXPECTED
TO DEVELOP OVR THE HYR TRRN. THE SERN PLAINS SHOULD BE DRY ON
MONDAY. IN GENERAL...HIGH TEMPS SHOULD BE ABOUT 5-10 DEGREE ABOVE
AVERAGE. /28
LONG TERM...
(MONDAY NIGHT THROUGH SUNDAY)
..HOT AND DRY WEATHER TO CONTINUE THROUGH NEXT WEEK...
NO CHANGES SEEN FOR THE EXTENDED FORECAST. ALL GUIDANCE POINTS TO
A CONTINUATION OF CURRENT CONDITIONS. HIGH PRESSURE CENTERED OVR
S CO WILL BE THE MAIN PLAYER...AND THIS WILL LEAVE THE ERN CO PLAINS
IN A VERY WARM AND GENERALLY DRY PATTERN THRU AT LEAST THE MIDDLE OF
THE WEEK. TEMPS SHOULD TOP OUT IN THE MID 90S...POSSIBLY HIGHER...FOR
A GOOD PORTION OF THE PLAINS BOTH TUE AND WED. POPS LOOK PRETTY LOW
OVER THE PLAINS...AND ONLY SCT STORMS ARE EXPECTED OVR THE MTS FOR
THIS PERIOD.
MAIN QUESTION IS HOW QUICKLY THE UPPER RIDGE BREAKS DOWN. THE ECMWF
MAINTAINS A STRONG UPPER HIGH...AND KEEPS MOST OF THE ACTIVE WX TO
OUR N THRU THE END OF THE WEEK AND EVEN INTO NEXT WEEKEND. THE GFS IS
STILL MORE OPTIMISTIC AND BRINGS AT LEAST A LOW CHANCE OF PRECIP E
OF THE MTS AS A SERIES OF WEAK FRONTAL PUSHES MOVE ACROSS THE AREA
THU AND SAT NEXT WEEK. WILL STICK CLOSER TO PERSISTENCE FOR NOW AND
STAY CLOSE TO THE ENSEMBLE CONSENSUS...WHICH IS CLOSE TO THE OP
ECMWF FORECAST OF DRY AND VERY WARM CONDITIONS. 44
AVIATION...
SOME SHOWERS AND THUNDERSTORMS WILL CONTINUE OVR THE HYR TRRN INTO
THE EVENING BUT IS EXPECTED TO END BEFORE MIDNIGHT. KALS COULD SEE
SOME TSTMS IN THE VCNTY THRU ABOUT 02Z. AT KCOS AND KPUB...CHANCES
FOR TSTM LOOK QUITE LOW. VFR CONDITIONS ARE EXPECTED AT THE TAF
SITE FOR THE NEXT 24 HRS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27/34
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT MON AUG 27 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
MOISTURE FOCUSED FARTHER S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 127 AM EDT MON AUG 27 2012
EXPECT FOG AT SAW TO GRADUALLY LIFT EARLY THIS MRNG WITH THE ARRIVAL
OF DRIER AIR ASSOCIATED WITH HI PRES BLDG E FM THE PLAINS.
OTHERWISE...THIS DRY AIR WL BRING VFR CONDITIONS THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
ACROSS LAKE SUPERIOR LATE FRIDAY BEHIND THE TROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...RESENT
NWS TWIN CITIES/CHANHASSEN MN
434 AM CDT MON AUG 27 2012
.DISCUSSION...
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
HIGH PRESSURE IS SETTLING SOUTHEAST ACROSS THE CWA EARLY THIS
MORNING. DRIER AIR HAS INVADED THE AREA WITH PW VALUES RANGING
FROM 0.5 TO 0.75 INCHES. TODAY WILL BE THE LAST MILD DAY FOR A
WHILE. LIGHT NORTHWESTERLY FLOW WILL KEEP DEW POINTS CONFINED TO
THE MID 50S...WHICH STILL MAY BE A BIT HIGH IF WE CAN MIX A BIT
HIGHER THAN CURRENT FORECAST SOUNDINGS SUGGEST. THIS FALLS WITHIN
THE HIGHER MAV MOS DEW POINTS /NEAR 60/ AND THE LOWER MET MOS
/UPPER 40S/. EITHER SOLUTION TENDS TO BE ON THE TOO MOIST OR TOO
DRY SIDE. HIGHS TODAY MAY BE A DEGREE OR SO COOLER THAN YESTERDAY
WITH 925 MB TEMPS OF +21C NORTHEAST TO +24 SOUTHWEST...OR LOWER
80S TO UPPER 80S...RESPECTIVELY.
HIGH PRESSURE SLIDES TO THE EAST TO THE GREAT LAKES TONIGHT.
MEANWHILE...A FAIRLY WELL-DEFINED WARM FRONT WILL DEVELOP FROM THE
SD/NE BORDER ESE ACROSS NRN IA. IN ADDITION...THE 850MB JET IS
EXPECTED TO STRENGTHEN BENEATH THE EML TO 20 TO 30 KTS ACROSS SRN
SD. NAM IS MUCH MORE BULLISH AT 35 TO 40 KTS NOSING INTO SWRN MN.
FINALLY...RAPID MOISTENING ALONG THE 310-315K SURFACES...AND DECENT
ISENTROPIC UPGLIDE...SHOULD BE ENOUGH TO SUSTAIN AT LEAST A LITTLE
ELEVATED THUNDERSTORM ACTIVITY LATE TONIGHT ACROSS SOUTHWEST AND
SOUTH CENTRAL MN. STORMS WOULD MOST LIKELY FORM OVER ERN SD AND
DRIFT SOUTHEAST ALONG THE FRONT. STEEP MID LEVEL LAPSE RATES MAY
PROMOTE A LITTLE HAIL WITH SOME STORMS AS WELL. MOS POPS APPEAR
TOO LOW IN THIS SITUATION...AND EVEN NAM/GFS/ECMWF DETERMINISTIC
MODELS PAINT SOME QPF IN THESE AREAS LATE TONIGHT SO WILL
INTRODUCE SCHC POPS FOR NOW.
THE WARM FRONT WILL BEGIN TO LIFT NORTHEAST TUESDAY...BUT PROBABLY
WON/T REACH THE I-94 CORRIDOR. HOTTER TEMPERATURES ARE EXPECTED
WITH WAA BEGINNING TO REALLY KICK IN...ESPECIALLY SOUTH OF THE
FRONT. A FEW STORMS REMAIN POSSIBLE ALONG THE FRONT...PRIMARILY IN
THE MORNING BEFORE THE LLJ WEAKENS. STORMS SHOULD REMAIN ISOLATED
WITH CAP AT 850 MB NOT LIKELY TO BREAK TUESDAY AFTERNOON.
COULD SEE A FEW MORE STORMS TUESDAY NIGHT AS THE LLJ RAMPS UP
AGAIN...BUT THE JET IS ORIENTED MORE WSW/ENE AND NOT
PERPENDICULAR TO THE FRONT. THUS...LEFT POPS OUT FOR NOW TUESDAY
NIGHT.
.LONG TERM...WEDNESDAY THROUGH SUNDAY.
THE HEAT IS REALLY ON FOR MID TO LATE WEEK AS A LARGE INTENSE RIDGE
BUILDS ACROSS THE UPPER MIDWEST. NAM AND DGEX CONTINUE TO BE
INCREDIBLY HOT WITH 850 MB TEMPS ON THE ORDER OF +30C AND 925 MB
TEMPS OF +38C. 2 METER HIGH TEMPS OFF BOTH MODELS ARE IN EXCESS OF
110 DEGREES IN PLACES WHICH WOULD CRUSH EVEN ALL-TIME RECORDS.
LUCKILY THE MAGNITUDE OF THIS HEAT SHOULD NOT APPROACH THESE VALUES
SINCE BOTH MODELS HAVE BEEN TOO HOT FOR MUCH OF THE SUMMER AND TEND
TO MIX THE ATMOSPHERE TO AN EXTREME DEGREE. HOWEVER...THE ECMWF
CONTINUES ITS TREND UPWARD WITH TEMPERATURES WEDNESDAY AND THURSDAY
AND NOW HAS 925 MB TEMPS APPROACH +29 TO +32C WITHIN THE THERMAL
RIDGE SETTLING OVERHEAD THURSDAY. GFS REMAINS AN EXTREME COLD
OUTLIER. GIVEN THAT THE COOLEST REASONABLE MODEL /ECMWF/ NOW
SUPPORTS HIGHS IN THE 92 TO 102 DEGREE RANGE FOR THIS
PERIOD...CONTINUED TO BUMP TEMPS UP INTO THE MID AND UPPER 90S BY
THURSDAY. EVEN HAVE SOME TEMPS EXCEEDING 100F OVER SWRN MN BUT IT
COULD BE WARMER STILL.
SERIOUSLY CONSIDERED ISSUING AN EXCESSIVE HEAT WATCH FOR WEDNESDAY
AND THURSDAY FOR THE MSP METRO...BUT HELD OFF BASED ON UNCERTAINTIES
WITH AFTERNOON DEW POINTS AND MIXING POTENTIAL AND IT IS STILL
BEYOND THE 4TH PERIOD. FUTURE SHIFTS WILL NEED TO REEVALUATE THIS
POSSIBILITY.
THE HEART OF THE RIDGE WILL SINK SOUTH A BIT FOR FRIDAY AND
SATURDAY...BUT HIGHS IN THE 90S ARE STILL EXPECTED SOUTH OF I-94
BOTH DAYS.
THEN EYES TURN TO THE REMNANTS OF ISAAC WHICH MODELS CONTINUE TO
SHIFT NORTHWESTWARD WITH EACH RUN. CONSENSUS AND THE OFFICIAL NHC
TRACK NOW BRING IT INTO CENTRAL MISSOURI BY FRIDAY NIGHT BEFORE A
LIKELY RECURVATURE INTO THE LOWER GREAT LAKES BY SUNDAY AFTERNOON. A
FRONT WILL BE SAGGING SOUTH INTO THE CWA SATURDAY NIGHT AND SUNDAY
WITH SOUTHERLY FLOW EXPECTED TO WICK SOME OF ISAAC/S AMPLE MOISTURE
NORTHWARD. INTRODUCED A SLIGHT CHANCE OF TSRA WITH THE FRONT SUNDAY
FOR NOW BUT WILL NEED TO WATCH FOR EXCESSIVE RAINFALL FROM A
POTENTIAL "PREDECESSOR RAIN EVENT" SOMEWHERE IN THE UPPER MIDWEST
FROM ISAAC.
BORGHOFF
&&
.AVIATION.../00Z TAF ISSUANCE/
ONLY PROBLEM IN THE OVERNIGHT IS THE POTENTIAL FOR RADIATION FOG.
STILL HAVE SOME HIGHER DEWPOINTS OFF TOT EH SOUTH AND EAST...AND
WINDS ARE RATHER LIGHT WITH HIGH PRESSURE RIDGE IN PLACE. RAP AND
TO A LESSER DEGREE THE 00Z NAM WAS INDICATING SOME POTENTIAL FOR AT
LEAST SOME MVFR FOG. WILL MENTION THAT AT ALL BUT KAXN/KMSP FOR
NOW. KEAU MAY GO DOWN MORE SO DID GO IFR THERE AFTER 10Z. SHOULD
BURN OFF QUICKLY MONDAY MORNING AND SUNSHINE EXPECTED MST OF THE
DAY. THE NAM CONTINUES TO INDICATE SOME POTENTIAL OF MID LEVEL
CLOUDS DEVELOPING LATER MONDAY NIGHT. OVER WESTERN AREAS. WILL
MENTION SOME BASED AC THERE INTO THE EVENING. OTHERWISE VFR AFTER
POSSIBLE FOG TONIGHT. SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT
BECOMING NORTHWEST TO NORTH AND EVENTUALLY NORTHEAST AND THEN
SOUTHEAST OVER WESTERN TAF SITES INTO MONDAY NIGHT. SHOULD REMAIN
LESS THAN 10 KTS.
KMSP...VFR SKC OVERNIGHT THROUGH MONDAY. LIGHT/VARIABLE WIND
OVERNIGHT BECOMING NORTHWEST/NORTH MONDAY AND EVENTUALLY EAST INTO
MONDAY NIGHT. WILL REMAIN BELOW 10 KNOTS.
/OUTLOOK FOR KMSP/
TUESDAY...VFR. WINDS SE AT 5 TO 10 KTS.
WEDNESDAY...VFR. WINDS SW AT 10G15KTS.
THURSDAY...VFR. WINS SSW AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BORGHOFF/DE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1146 PM CDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 852 PM CDT SUN AUG 26 2012
THERE HAS BEEN AN OVERALL DECREASE IN AREA COVERAGE FOR -SHRA/ISOLD
-TSRA OVER THE PAST 1-2 HOURS NOW THAT THE SUN HAS SET AND THE
THROUGH AXIS HAS ENTERED THE NORTHWEST PART OF THE CWA. HAVE
CONTINUED LIKELY POPS OVER THE SRN AND ERN PARTS OF THE CWA INTO
THE OVERNIGHT HOURS WHERE THE RAP IS SHOWING DECENT LOW LEVEL
MOISTURE CONVERGENCE JUST AHEAD OF THE TROUGH. HAVE ALSO BEGAN TO
TRIM BACK ON RAIN CHANCES BEHIND THE TROUGH AXIS. OTHERWISE...
GOING FORECAST LOOKS ON TRACK AND ONLY MADE MINOR TWEAKS TO IT
BASED ON CURRENT TRENDS.
BRITT
&&
.SHORT TERM...
ISSUED AT 237 PM CDT SUN AUG 26 2012
(TONIGHT AND MONDAY)
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TONIGHT
AS MID LEVEL TROF AND SURFACE TROF INTERACT WITH A VERY MOISTURE
RICH ATMOSPHERE. LOCALLY HEAVY DOWNPOURS WILL BE POSSIBLE...BUT
SEVERE WEATHER IS UNLIKELY GIVEN LIMITED INSTABILITY.
THIS AXIS OF RAINFALL WILL SLOWLY SHIFT SOUTHEAST AS DRIER AIR
MOVES IN FROM THE NORTH THANKS TO A SURFACE HIGH. WARMEST
TEMPERATURES ON MONDAY WILL BE NORTH OF INTERSTATE 70 THANKS TO
AFTERNOON SUNSHINE...AND COOLEST SOUTH WHERE CLOUD COVER AND SCT
CONVECTION WILL GRADUALLY COME TO AN END.
CVKING
&&
.LONG TERM...
ISSUED AT 237 PM CDT SUN AUG 26 2012
(TUESDAY THROUGH SUNDAY)
UPPER LEVEL RIDGE WILL BUILD INTO THE MIDWEST WITH SLIGHTLY ABOVE
NORMAL TEMPERATURES EXPECTED THROUGH THURSDAY. HAVE FOLLOWED
LATEST NATIONAL HURRICANE CENTER FORECAST AND HPC GUIDANCE FOR THE
EXTENDED FORECAST WITH THE REMNANTS OF ISAAC BRUSHING THE EASTERN
HALF OF THE CWA LATE THIS WEEK AND EARLY NEXT WEEKEND. CHANGES IN
THE FORECAST INCLUDE CHANCE POPS AND COOLER TEMPERATURES FOR THE
SOUTHEAST HALF OF THE CWA. THIS CHANGE IN THE FORECAST IS DUE TO
THE TRACK OF THE HURRICANE BEING SHIFTED 150 MILES TO THE WEST
OVER THE PAST 24 HOURS BY NHC. MORE CHANGES ARE LIKELY IN THE
TRACK AND THIS WILL OBVIOULSY HAVE A BIG IMPACT ON OUR WEATHER
LATE THIS WEEK AND NEXT WEEKEND. SO STAY TUNED.
CVKING
&&
.AVIATION...
ISSUED AT 1140 PM CDT SUN AUG 26 2012
850 FRONT/TROF APPEARS TP BE BETWEEN QUINCY AND ST. LOUIS. THERE
WERE A FEW ALONG THIS FEATURE BUT THEY ARE DYING. MAIN BAND OD
SHOWERS HAS MOVED SOUTH OF ALL TERMINAL. MAIN ISSUE TONIGHT WILL
BE DEVELOPMENT OF FOG AND STRATUS. SATELLITE SHOWER AREA OF STATUS
DEVELOPING OVER WEST CENTRAL ILLINOIS SPREADING TO THE SOUTH.
EXPEDT THIS TREND TO CONTINUE. GIVER LIGHT NORTH SURFACE WIND
EXPECT FOG AND STRATUS TO HOLD ON UNTIL ABOUT 18Z MONDAY.
SPECIFICS FOR KSTL...AS MID CLOUD DECK CLEAR EXPECT TO SEE SOME
FOG DEVELOP. STARTUS SHOULD ALSO BUILD IN FROM THE NORTH. WITH A
LIGHT NORTHERLY WIND BELIEVE THE FOG/STRTUS MAY HOLD ON UNTIL
ABOUT 18Z MONDAY. CLEARING MONDAY NIGHT WITH SOME FOG DEVELOPING
AGAIN TUESDAY MORNING.
JPK
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
333 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE OHIO VALLEY THROUGH THIS
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
REGION. HIGH PRESSURE WILL THEN BUILD IN ACROSS THE GREAT LAKES
THROUGH THE REST OF THE WORK WEEK...RESULTING IN DRY CONDITIONS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WIDESPREAD SHOWER ACTIVITY ALONG WITH SOME EMBEDDED THUNDERSTORMS
IS PUSHING SLOWLY EAST ACROSS NORTHERN INDIANA OVER INTO NORTHWEST
OHIO THIS MORNING. SHOWER ACTIVITY TO THE SOUTHWEST OF THIS IS MORE
SCATTERED...STRETCHING DOWN INTO SOUTHERN ILLINOIS. THE PCPN IS
ASSOCIATED WITH A MID LEVEL SHORT WAVE ALONG WITH A WEAK COLD
FRONT THAT IS FORECAST TO PUSH EAST ACROSS OUR AREA THIS
AFTERNOON. STILL EXPECT THE HIGHEST POPS TO BE ACROSS OUR
NORTH...CLOSER TO THE TRACK OF THE SHORT WAVE. HOWEVER...THE LAST
FEW RUNS OF THE HRRR ARE TRYING TO DEVELOP SOME BETTER PCPN ACROSS
CENTRAL PORTIONS OF OUR FA...AND THIS SEEMS TO BE GETTING SOME
SUPPORT BY THE LATEST RAP AND EVEN THE 00Z NAM. INTERESTINGLY...THE
NAM IS MAINTAINING A COMPACT 20-30 KNOT 850 KNOT JET AS IT PIVOTS
ACROSS THE AREA THROUGH THIS AFTERNOON. TEMPERATURE FORECAST AND
INSTABILITY ARE SOMEWHAT PROBLEMATIC DEPENDING ON HOW FAST CLOUDS/PCPN
OVERSPREAD THE AREA THROUGH THE REMAINDER OF THE MORNING/EARLY AFTERNOON.
THIS COULD KEEP PCPN MORE SHOWERY WITH SOME EMBEDDED ISOLATED TO
SCATTERED THUNDERSTORMS. EXPECT WARMEST TEMPERATURES TO BE ACROSS
OUR SOUTHEAST WHERE CLOUDS/PCPN SHOULD ARRIVE LAST. WILL RANGE
HIGHS FROM THE LOWER 80S NORTHWEST TO MID AND UPPER 80S ACROSS THE
SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
PCPN SHOULD GENERALLY TAPER OFF THROUGH THE OVERNIGHT HOURS AS
SHORT WAVE PUSHES OFF TO THE EAST. HOWEVER...IT WILL BE TOUGH TO
RULE OUT SOME LINGERING SHOWERS ACROSS THE SOUTH AS THE FRONT
LINGERS ALONG THE OHIO RIVER. HIGH PRESSURE WILL THEN BUILD DOWN
ACROSS THE GREAT LAKES TUESDAY INTO WEDNESDAY. HIGHS BOTH DAYS
WILL BE IN THE LOW TO MID 80S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LARGE SFC HIGH PRESSURE STRETCHING FROM THE EASTERN GREAT LAKES BACK
INTO THE PLAINS WILL DOMINATE THE REGIONS WEATHER AT THE BEGINNING
OF THE PERIOD. THE HIGH BEGINS TO TRANSITION EASTWARD ON THURSDAY
ALLOWING ROOM FOR ISAAC TO MAKE LANDFALL.
THE OFFICIAL TRACK OF ISAAC HAS TRENDED W TODAY...FOLLOWING A GOOD
NUMBER OF THE OPERATIONS MODELS TRENDS. THE 12Z GFS IS THE FARTHEST
W WITH THE LANDFALL...PUSHING IT INLAND AROUND PORT ARTHUR TX. THE
CANADIAN AND NOGAPS ARE CLOSE TO THE NHC TRACK WITH LANDFALL IN
MS...WHILE THE 12Z ECMWF BRINGS IT ONSHORE IN ALABAMA.
THERE IS A WIDE SPREAD IN PATH AFTER LANDFALL. THE GFS TAKES THE LOW
INTO PLAINS BEFORE RECURVING UP THE OHIO VALLEY. THE OTHER MODELS
TAKE THE CIRCULATION UP THROUGH THE MS VALLEY OR WRN TN/KY AT
VARYING SPEEDS. CONFIDENCE IS LOW WITH THE WEEKEND FORECAST. THE
TREND OF THE MODELS WITH ISAAC HAS BEEN WESTWARD...SO IT COULD MAKE
LANDFALL IN LOUISIANA OR ERN TX. IF IT GOES THIS FAR W...THE ONSET
OF THE PCPN COULD BE DELAYED OR IT COULD DRY UP.
FOR NOW...FOLLOWED THE HPC SOLUTION WHICH BRINGS THE SFC LOW TO WRN
KY BY SATURDAY MORNING AND LOW CHC PCPN UP INTO THE REGION FRIDAY.
CHANCE OF PCPN SHOULD INCREASE OVER THE WEEKEND...BUT KEPT POPS IN
THE CHC CATEGORY FOR NOW.
AS THE HIGH SLIDES EAST BY THURSDAY...TEMPERATURES WILL BEGIN TO
WARM....WITH HIGHS IN THE MID 80S TO LOWER 90S. THEY COULD GET A
LITTLE WARMER WITH THE SUBSIDENCE AHEAD OF THE HURRICANE...SO WILL
HAVE TO KEEP AN EYE ON THE THIS IN LATER FORECASTS. WITH CLOUDS
AND PCPN WORKING IN FOR THE END OF THE FA PERIOD...LOWERED
TEMPERATURES BACK INTO THE LOWER TO MID 80S FOR SATURDAY AND
SUNDAY...BUT THEY COULD BE COOLER THE PCPN HOLDS TOGETHER MORE.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS ARE EXPECTED THROUGHOUT TONIGHT. MID AND HIGH
LEVEL CLOUDS WILL SPREAD ACROSS THE AREA DURING THE MORNING HOURS
AHEAD OF AN APPROACHING COLD FRONT. CONVECTION ACROSS INDIANA WILL
GRADUALLY WEAKEN AS IT MOVES INTO OUR AREA THIS MORNING...HOWEVER
SOME OF THIS ACTIVITY SHOULD HOLD TOGETHER TO PRODUCE LIGHT RAIN
MAINLY ACROSS THE WESTERN TERMINALS. BY THIS AFTERNOON...THE
FRONTAL BOUNDARY WILL PUSH EAST ACROSS THE AREA WITH SOME
THUNDERSTORM ACTIVITY DEVELOPING JUST AHEAD OF IT. ENOUGH
UNCERTAINTY STILL REMAINS IN TIMING FOR THIS CONVECTION...SO HAVE
HELD OF ON ANY TEMPOS FOR NOW. ALONG THE FRONTAL BOUNDARY...MVFR
CIGS WILL BE POSSIBLE...MAINLY ACROSS THE NORTHWEST THIS
AFTERNOON. MODELS ARE ALSO HINTING AT POTENTIAL LOWER CIGS TONIGHT
AS COLD ADVECTION MAY DEVELOP A LOW STRATUS DECK ACROSS THE EAST. WILL
CONTINUE TO MONITOR TRENDS FOR THIS POSSIBILITY.
.OUTLOOK...NO SIGNIFICANT WEATHER.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1200 AM CDT MON AUG 27 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
1200 AM CDT MON AUG 27 2012
MIDNIGHT UPDATE...WITH FOG EXPANDING ACROSS SOUTHWEST WISCONSIN AND
FAR NORTHEAST IOWA...WHERE IT RAINED DECENTLY YESTERDAY AND CLEARED
OUT LATE...WILL BE ISSUING A DENSE FOG ADVISORY.
DRY CONDITIONS EXPECTED THROUGH MID WEEK WITH THE MAIN FORECAST
FOCUS BEING ON TEMPERATURES AND FOG.
CURRENTLY...A SYSTEM THAT BROUGHT RAIN AND CLOUD COVER TO THE
REGION TODAY IS SLOWLY RETREATING EAST INTO THE GREAT LAKES. RAIN
HAS COME TO AN END WITH THE UPPER LEVEL TROUGH PUSHING INTO EASTERN
WISCONSIN. THE QUESTION FOR TONIGHT IS WITH HOW FAST THE CLOUDS
CLEAR OUT AND WHETHER ANY FOG WILL DEVELOP AS IT DID ACROSS
WESTERN MINNESOTA/IOWA THIS MORNING. THE 26.18Z RAP MOISTURE
FIELDS SHOW THE DEEPER MOISTURE FIELD ASSOCIATED WITH THE TROUGH
AND RAINFALL SHIFTING EAST BY THIS EVENING. ALSO...THE STRATUS
FIELD ALONG THE WESTERN SIDE OF THE TROUGH HAS BECOME MUCH MORE
CELLULAR AND SHOULD THIN OUT THIS EVENING AND LEAD TO CLEAR SKIES
THOUGH OUT THE REGION OVERNIGHT.
WITH THESE CLEARING SKIES...LIGHT WINDS...AND A RIDGE AXIS OF
HIGH PRESSURE PUSHING IN...WILL LIKELY SEE SOME FOG FORM ACROSS
THE REGION. THE BEST CHANCES FOR WIDESPREAD AND POSSIBLY DENSE FOG
WILL BE ACROSS SOUTHERN WISCONSIN INTO EASTERN IOWA WHERE THE RAIN
AND CLOUDS HOLD ON LONGER TODAY BEFORE CLEARING OUT LATER TONIGHT.
SHOULD ALSO SEE FOG FORM IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS TONIGHT AS WELL THOUGH HOW WIDESPREAD IT BECOMES WILL BE
DEPENDENT UPON THE LOW LEVEL WIND FIELDS. SEE THE LATEST AVIATION
AFD FOR FURTHER/UPDATED DETAILS ON THE POTENTIAL FOR THIS VALLEY
FOG.
GOING INTO THE EARLY TO MID PORTIONS OF THE WEEK...WARMER AIR WILL
SLOWLY ADVECT INTO THE REGION FROM THE WEST AS A SURFACE RIDGE OF
HIGH PRESSURE SETTLES OVER THE UPPER MISSISSIPPI RIVER VALLEY AND
AN UPPER LEVEL RIDGE BUILDS ACROSS THE ROCKIES. WILL HAVE TO WATCH
A WARM FRONT THAT SURGES NORTHWARD TUESDAY INTO WEDNESDAY AS THE
26.12Z NAM AND GFS TRY TO PRODUCE SOME ELEVATED CONVECTION ACROSS
MINNESOTA WESTERN WISCONSIN. CONFIDENCE IS NOT HIGH THAT THIS
CONVECTION WILL OCCUR GIVEN THE DRY LOW LEVELS AND BETTER MOISTURE
TRANSPORT OFF TO THE WEST...SO HAVE KEPT THE FORECAST DRY THROUGH
THIS PERIOD BUT HAVE PUT SOME SLIGHTLY HIGHER CLOUD COVER IN OVER
THIS TIME FRAME. OTHERWISE EXPECT TEMPERATURES TO SLOWLY REBOUND
GOING INTO MID WEEK AS WARMER AIR SPILLS TO THE EAST AS THE
WESTERN RIDGE BUILDS EASTWARD INTO THE REGION WITH 850MB
TEMPERATURES CLIMBING FROM AROUND +13C ON MONDAY TO AROUND +23C BY
WEDNESDAY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
227 PM CDT SUN AUG 26 2012
THE MAIN STORY FOR THE LATER PART OF THE WEEK WITH WITH THE WARM
AIR MASS THAT WILL TAKE OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. AFTER THE WARM FRONT LIFTS NORTH OF THE REGION ON
WEDNESDAY...STRONG SOUTHERLY LOW LEVEL FLOW WILL KICK IN FROM THE
SOUTHERN PLAINS UP INTO THE GREAT LAKES AND NORTHERN PLAINS. THE
BUILDING RIDGE ACROSS THE ROCKIES WILL BEGIN TO SHIFT TO THE EAST
WEDNESDAY NIGHT INTO THURSDAY WITH THURSDAY LOOKING LIKE THE
WARMEST DAY OF THE WEEK. 850MB TEMPERATURE ANOMALIES FROM THE
26.12Z GFS AND ECMWF SHOW THAT THE +23C 850MB TEMPERATURES ARE
ABOUT 2 STANDARD DEVIATIONS ABOVE THE NORM...WHICH WOULD PUSH
RECORD HIGHS IN THE MID 90S. WITH THE WARMER AIR GRADUALLY
GETTING INTO THE REGION...HAVE GONE WITH A GRADUAL WARMING TREND
WITH THE NEAR RECORD HIGHS FOR THURSDAY. PRECIPITATION CHANCES
WILL BE MINIMAL UNTIL MAYBE NEXT WEEKEND AS A COLD FRONT DROPS
DOWN THROUGH LAKE SUPERIOR. THE 26.12Z GFS IS MORE PROGRESSIVE
WITH BRINGING THE FRONT SOUTH THROUGH THE REGION WHILE THE 26.12Z
ECMWF KEEPS THE FRONT TO THE NORTH. THE 26.12Z GFS IS ALSO ON THE
WESTERN TRACK WITH THE REMNANTS OF ISAAC COMING NORTH ALONG THE
MISSISSIPPI WHILE THE 26.12Z KEEPS IT WELL TO THE SOUTHEAST.
CONFIDENCE IS NOT VERY HIGH WITH WHERE THIS FEATURE WILL
TRACK...BUT THERE IS A BETTER CHANCE THAT IT WILL STAY TO THE
SOUTHEAST AND NOT COME INTO THE REGION. THEREFORE...HAVE KEPT THE
FORECAST MAINLY DRY THROUGH NEXT WEEKEND.
&&
.AVIATION...THROUGH 06Z TUESDAY
1200 AM CDT MON AUG 27 2012
RADIATION GROUND FOG HAS DEVELOPED AT KLSE...DUE TO LIGHT WINDS AND
LINGERING HIGH SURFACE DEWPOINTS. VISIBILITIES HAVE BEEN BOUNCING
BETWEEN MVFR AND VLIFR. ANTICIPATING TO THIS CONTINUE THE NEXT 2 TO
4 HOURS...OR PERHAPS THROUGH THE REST OF THE NIGHT. SHOULD VALLEY
FOG FORM...VLIFR CONDITIONS WILL HOLD IN PLACE. STILL SOMEWHAT
QUESTIONABLE ABOUT VALLEY FOG...GIVEN A TROUGH EXPECTED TO COME
THROUGH AROUND 08Z AND ALLOW NORTHWEST WINDS TO PICK UP.
STILL...COOLING TEMPERATURES SHOULD KEEP RADIATION FOG GOING. AS
SUCH...WENT MORE PESSIMISTIC WITH THE FORECAST FOR KLSE...STAYING
VLIFR UNTIL 13Z. ONCE THE SUN COMES UP AND STARTS MIXING...KLSE
SHOULD QUICKLY GO TO VFR BY 14Z. VFR CONDITIONS ARE THEN EXPECTED
THROUGH 06Z TUESDAY AS FURTHER DRYING TAKES PLACE.
AT KRST...A STEADY 4-6 KT NORTHWEST BREEZE BRINGING IN DRIER AIR
WILL KEEP VFR CONDITIONS THERE THROUGH THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1159 PM CDT SUN AUG 26 2012
WI...DENSE FOG ADVISORY UNTIL 8 AM CDT MONDAY FOR WIZ042>044-053>055-
061.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL 8 AM CDT MONDAY FOR IAZ011-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS ALBANY NY
647 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY TOWARDS THE
NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 636 AM EDT...A SHORTWAVE TROUGH WAS MOVING ACROSS THE UPPER
GREAT LAKES THIS MORNING...WITH A SFC COLD FRONT MOVING ACROSS THE
MIDWEST. THIS TROUGH WILL QUICKLY MOVE EASTWARD ACROSS THE GREAT
LAKES THROUGH THE DAY TODAY.
AHEAD OF THIS SYSTEM...ANOTHER WEAK OPEN WAVE TROUGH WAS SITUATED
OVER THE MID ATLANTIC STATES. A SOUTHERLY FLOW HAS ALLOWED FOR
SOME STRATUS TO DEVELOP ACROSS PA/NJ...AND SOME
OF THESE LOW CLOUDS HAVE MOVED INTO PORTIONS OF THE EASTERN
CATSKILLS. HAVE GONE WITH MOSTLY CLOUDY FOR SOUTHWESTERN PARTS OF
THE AREA FOR THE EARLY TO MID MORNING HOURS. ELSEWHERE...MOSTLY CLEAR
SKIES WILL GRADUALLY GIVE WAY TO INCREASING AMOUNTS OF MID AND HIGH
LEVEL CLOUDINESS. WITH A PERSISTENT SOUTHERLY FLOW AND THE NEARBY
WEAK TROUGH OVER THE NORTHERN MID ATLANTIC STATES...A FEW LIGHT RAIN
SHOWERS OR ISOLD THUNDERSTORMS MAY DEVELOP FROM THE MID MORNING INTO
THE EARLY AFTERNOON HOURS. THE LATEST 07 UTC 3KM HRRR SHOWS SOME
ACTIVITY MOVING UP FROM THE SOUTH BY THE LATE MORNING. THE MOST
RECENT REGIONAL MOSAIC RADAR SHOWS SOME SHOWERS ALREADY ACROSS
EASTERN PA...AND WE WILL NEED TO WATCH THE EVOLUTION OF THESE
SHOWERS AS THEY LIFT N-NE. HAVE DECIDED TO INCLUDE AN ISOLD THUNDER
MENTION...AS THE THE 06 UTC NAM12 NOW SHOWS SOME INSTABILITY DURING
THE DAYTIME HOURS TODAY.
THE STRONGEST FORCING ASSOCIATED WITH THE MIDWEST SHORTWAVE
TROUGH WILL REMAIN WELL TO THE WEST THROUGH THE MID AFTERNOON. BY
LATER IN THE AFTERNOON...A SFC PRE FRONTAL TROUGH MAY DEVELOP AND
ALLOW FOR MORE SCT SHOWER ACTIVITY ACROSS THE AREA FOR THE LATE AFTN
HOURS. WILL CONTINUE TO MENTION THE ISOLD THREAT FOR SOME THUNDER.
MAX TEMPS WILL RANGE FROM THE UPPER 70S TO LOW 80S IN MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
THERE MAY BE A BRIEF BREAK IN THE ACTIVITY DURING THE EARLY
EVENING HOURS...AS THE REGION WILL BE BETWEEN THE PRE FRONTAL
TROUGH AND THE ACTUAL APPROACHING SFC COLD FRONT/UPPER TROUGH.
BY LATER IN THE EVENING...THE REGION WILL BE BETTER LOCATED IN THE
FRONT ENTRANCE REGION OF AN 80 KT JET STREAK SITUATED OVER
NORTHERN NEW ENGLAND...AND THE UPPER TROUGH WILL BE QUICKLY
APPROACHING. THIS WILL ALLOW MORE WIDESPREAD SHOWERS TO DEVELOP.
WITH THE APPROACHING UPPER TROUGH...THERE WILL BE A LITTLE MORE
INSTABILITY...SO WILL CONTINUE TO INCLUDE THUNDER FOR THE
OVERNIGHT HOURS...AS THERE MAY BE SOME EMBEDDED RUMBLES OF
THUNDER...ALTHOUGH SEVERE WEATHER IS NOT ANTICIPATED DUE TO THE
SMALL AMOUNTS OF INSTABILITY AND LACK OF STRONG 0-6 KM BULK SHEAR.
STILL...SOME OF THE SHOWERS MAY HAVE SOME HEAVY DOWNPOURS...SEE
THE HYDRO SECTION BELOW FOR MORE INFORMATION REGARDING HOW THIS
MAY IMPACT AREA RIVERS AND STREAMS. WITH THE CLOUDS AND
RAINFALL...IT WILL BE A WARM AND MUGGY NIGHT. MANY AREAS WILL ONLY
DROP INTO THE MID TO UPPER 60S FOR LOWS.
THE MODELS ARE IN GOOD AGREEMENT THAT THE BEST CHANCE FOR
SHOWERS/STORMS LOOKS BETWEEN THE LATE EVENING AND EARLY MORNING
HOURS OF TUESDAY...SO HAVE GONE WITH LIKELY POPS ACROSS MUCH OF
THE AREA DURING THIS TIME PERIOD. THE SFC COLD FRONT WILL PASS
FROM WEST TO EAST DURING THE MORNING HOURS. THIS SHOULD ALLOW
WINDS TO SWITCH AROUND TO THE W-NW AND END THE THREAT OF SHOWERS.
MOST AREAS SHOULD BE RAIN FREE BY THE AFTERNOON HOURS...ALTHOUGH
THE THREAT FOR A SHOWER MAY LINGER IN WESTERN NEW ENGLAND INTO THE
MID AFTN. MAX TEMPS WILL RANGE FROM NEAR 70 IN THE ADIRONDACKS TO
THE MID 80S IN FAR SOUTHEASTERN AREAS...WHERE THE FRONT WILL TAKE
LONGEST TO CROSS.
A LARGE AREA OF HIGH PRESSURE OVER THE MIDWEST WILL SHIFT EASTWARD
TOWARDS THE REGION FOR TOMORROW NIGHT. THIS WILL ALLOW DRY WEATHER
TO RETURN TO THE AREA FOR TOMORROW NIGHT THROUGH THE REMAINDER OF
THE SHORT TERM PERIOD. COOLER AND LESS HUMID WILL MAKE ITS WAY
INTO THE AREA. WITH GOOD RADIATIONAL COOLING EXPECTED...LOWS
TOMORROW NIGHT WILL RANGE FROM THE MID 40S TO THE MID 50S ACROSS
THE AREA WITH CLEARING SKIES. MAX TEMPS ON WED WILL ONLY BE IN THE
70S ACROSS THE AREA...WITH THESE HIGHS BEING A FEW DEGREES BELOW
NORMAL. ANOTHER COOL NIGHT IS EXPECTED FOR WED NIGHT WITH MID 40S
TO MID 50S WITH A NEARLY CLEAR SKY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
RIDGING IS EXPECTED TO DOMINATE LATE IN THE WEEK WITH UNCERTAINTY
IN THE FORECAST GROWING OVER THE WEEKEND. THE GFS AND ECMWF ARE IN
GOOD AGREEMENT KEEPING THE REGION DRY THROUGH SATURDAY WITH RIDGING
ALOFT ACROSS THE NORTHEAST AND HIGH PRESSURE AT THE SURFACE ALONG
THE EAST COAST. ABOVE NORMAL TEMPERATURES ARE ANTICIPATED ESPECIALLY
FRIDAY AND SATURDAY BY AROUND 10 DEGREES.
AFTER LANDFALL ISAAC WILL WEAKENED AS IT MOVES INLAND. SOME MODEL
GUIDANCE INDICATES THE REMNANT MOISTURE FROM ISAAC MAY AFFECT OUR
REGION LATE IN THE WEEKEND INTO EARLY NEXT WEEK. PLEASE REFER TO
PRODUCTS ISSUED BY THE NATIONAL HURRICANE CENTER FOR THE OFFICIAL
FORECAST TRACK OF TROPICAL STORM ISAAC.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL CONTINUE TO SHIFT EASTWARD AND OFF THE NEW
ENGLAND COAST TODAY. A SLOW MOVING COLD FRONT WILL APPROACH AND MOVE
ACROSS THE REGION BRINGING INCREASING CHANCES OF SHOWERS AND SOME
THUNDERSTORMS THIS AFTERNOON AND ESPECIALLY TONIGHT.
MAINLY VFR CONDITIONS PERSIST EARLY THIS MORNING...EXCEPTION IS AT
KGFL WHERE RADIATIONAL FOG DEVELOPED. ALSO HAVE SOME STRATUS ACROSS
PORTIONS OF THE LOCAL AREA WHICH IMPACTED KPSF AND KPOU EARLIER THIS
MORNING. THE STRATUS WILL LIFT/BREAK UP AND THE FOG WILL BURN OFF.
ALSO HAVE CLOUDS ADVANCING IN FROM THE WEST AHEAD OF THE COLD FRONT.
CHANCES FOR CONVECTION WILL INCREASE AS THE AFTERNOON PROGRESSES AS
A PREFRONTAL TROUGH MOVES ACROSS THE REGION. THERE MAY BE A LULL IN
THE ACTIVITY THIS EVENING FOR A PERIOD BETWEEN THE PREFRONTAL TROUGH
AND THE COLD FRONT. WILL HAVE BETTER CHANCES FOR CONVECTION WITH THE
COLD FRONT AS IT WILL HAVE BETTER SUPPORT. EXCEPT WIDESPREAD MVFR
CONDITIONS TO DEVELOP WITH IFR POSSIBLE AS HEAVY DOWNPOURS WILL
OCCUR WITH SOME OF THE CONVECTION.
SOUTHERLY FLOW TODAY WITH THE STRONGEST WINDS DURING THE AFTERNOON
WITH SOME GUSTS UP TO AROUND 20 KTS AT KALB DUE TO THE FUNNELING
EFFECT UP THE HUDSON RIVER VALLEY. WINDS WILL LIGHTEN UP DURING THE
EVENING AND REMAIN SOUTHERLY.
OUTLOOK...
TUE...IMPROVING TO VFR. SHRA/TSRA LIKELY IN THE MORNING ESPECIALLY
EARLY.
WED-FRI...VFR.
&&
.FIRE WEATHER...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY TOWARDS THE
NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
RELATIVE HUMIDITIES WILL ONLY FALL TO ABOUT 50-60 PERCENT THIS
AFTERNOON. RELATIVE HUMIDITIES TONIGHT WITH THE RAIN SHOULD APPROACH
100 PERCENT...THEN AS THE FRONT EXITS TUESDAY...RELATIVE
HUMIDITIES SHOULD DRY OUT TO THE 45 TO 55 PERCENT RANGE. RH VALUES
WILL THEN ONCE AGAIN APPROACH 100 PERCENT TOMORROW NIGHT.
SOUTH TO SOUTHWEST WINDS WILL PICK UP TO 10-15 MPH THIS AFTERNOON.
WEST TO SOUTHWEST WINDS WILL DROP TO AROUND 5 MPH TONIGHT. WINDS
WILL SWITCH TO A WEST TO NORTHWEST WINDS IN THE WAKE OF THE FRONT
FOR TOMORROW AFTERNOON AT SPEEDS OF 10-18 MPH WITH A FEW HIGHER
GUSTS POSSIBLE. WINDS WILL QUICKLY DROP OFF TO NEARLY CALM FOR
TOMORROW NIGHT.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.
NUMEROUS SHOWERS AND SOME EMBEDDED THUNDERSTORMS WILL OCCUR FOR
LATER TODAY THROUGH TONIGHT AND INTO TUESDAY MORNING. WITH PWAT
VALUES AROUND 1.75 INCHES THROUGH THIS PERIOD...SOME HEAVY
DOWNPOURS ARE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. THIS MAY LEAD TO PONDING OF WATER ON AREA ROADWAYS
AND IN AREAS OF POOR DRAINAGE. ALTHOUGH LOCALLY HIGHER AMOUNTS
ARE POSSIBLE...TOTAL AREAL QPF AMOUNTS WILL LIKELY BE AROUND A
HALF TO THREE QUARTERS OF AN INCH. AS A RESULT...WIDESPREAD
FLOODING IS NOT ANTICIPATED...AND DUE TO SUCH DRY ANTECEDENT
CONDITIONS...THIS RAINFALL WILL BE ABSORBED INTO THE GROUND...AND
RUNOFF WILL BE MINIMAL. THIS RAINFALL SHOULD ONLY ALLOW FOR SOME
SMALL RISES ON AREA RIVERS AND STREAMS AT MOST...WITH SOME LARGER
MAINSTEM RIVERS HOLDING STEADY.
MAINLY DRY WEATHER RETURNS TUESDAY AFTERNOON AND SHOULD LAST
THROUGH THE REST OF THE WORK WEEK.
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...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
636 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY TOWARDS THE
NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 636 AM EDT...A SHORTWAVE TROUGH WAS MOVING ACROSS THE UPPER
GREAT LAKES THIS MORNING...WITH A SFC COLD FRONT MOVING ACROSS THE
MIDWEST. THIS TROUGH WILL QUICKLY MOVE EASTWARD ACROSS THE GREAT
LAKES THROUGH THE DAY TODAY.
AHEAD OF THIS SYSTEM...ANOTHER WEAK OPEN WAVE TROUGH WAS SITUATED
OVER THE MID ATLANTIC STATES. A SOUTHERLY FLOW HAS ALLOWED FOR
SOME STRATUS TO DEVELOP ACROSS PA/NJ...AND SOME
OF THESE LOW CLOUDS HAVE MOVED INTO PORTIONS OF THE EASTERN
CATSKILLS. HAVE GONE WITH MOSTLY CLOUDY FOR SOUTHWESTERN PARTS OF
THE AREA FOR THE EARLY TO MID MORNING HOURS. ELSEWHERE...MOSTLY CLEAR
SKIES WILL GRADUALLY GIVE WAY TO INCREASING AMOUNTS OF MID AND
HIGH LEVEL CLOUDINESS. WITH A PERSISTENT SOUTHERLY FLOW AND THE NEARBY
WEAK TROUGH OVER THE NORTHERN MID ATLANTIC STATES...A FEW LIGHT
RAIN SHOWERS OR ISOLD THUNDERSTORMS MAY DEVELOP FROM THE MID MORNING
INTO THE EARLY AFTERNOON HOURS. THE LATEST 07 UTC 3KM HRRR SHOWS
SOME ACTIVITY MOVING UP FROM THE SOUTH BY THE LATE MORNING. THE
MOST RECENT REGIONAL MOSAIC RADAR SHOWS SOME SHOWERS ALREADY
ACROSS EASTERN PA...AND WE WILL NEED TO WATCH THE EVOLUTION OF
THESE SHOWERS AS THEY LIFT N-NE. HAVE DECIDED TO INCLUDE AN ISOLD
THUNDER MENTION...AS THE THE 06 UTC NAM12 NOW SHOWS SOME
INSTABILITY DURING THE DAYTIME HOURS TODAY.
THE STRONGEST FORCING ASSOCIATED WITH THE MIDWEST SHORTWAVE
TROUGH WILL REMAIN WELL TO THE WEST THROUGH THE MID AFTERNOON. BY
LATER IN THE AFTERNOON...A SFC PRE FRONTAL TROUGH MAY DEVELOP AND
ALLOW FOR MORE SCT SHOWER ACTIVITY ACROSS THE AREA FOR THE LATE
AFTN HOURS. WILL CONTINUE TO MENTION THE ISOLD THREAT FOR SOME THUNDER.
MAX TEMPS WILL RANGE FROM THE UPPER 70S TO LOW 80S IN MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
THERE MAY BE A BRIEF BREAK IN THE ACTIVITY DURING THE EARLY
EVENING HOURS...AS THE REGION WILL BE BETWEEN THE PRE FRONTAL
TROUGH AND THE ACTUAL APPROACHING SFC COLD FRONT/UPPER TROUGH.
BY LATER IN THE EVENING...THE REGION WILL BE BETTER LOCATED IN THE
FRONT ENTRANCE REGION OF AN 80 KT JET STREAK SITUATED OVER
NORTHERN NEW ENGLAND...AND THE UPPER TROUGH WILL BE QUICKLY
APPROACHING. THIS WILL ALLOW MORE WIDESPREAD SHOWERS TO DEVELOP.
WITH THE APPROACHING UPPER TROUGH...THERE WILL BE A LITTLE MORE
INSTABILITY...SO WILL CONTINUE TO INCLUDE THUNDER FOR THE
OVERNIGHT HOURS...AS THERE MAY BE SOME EMBEDDED RUMBLES OF
THUNDER...ALTHOUGH SEVERE WEATHER IS NOT ANTICIPATED DUE TO THE
SMALL AMOUNTS OF INSTABILITY AND LACK OF STRONG 0-6 KM BULK SHEAR.
STILL...SOME OF THE SHOWERS MAY HAVE SOME HEAVY DOWNPOURS...SEE
THE HYDRO SECTION BELOW FOR MORE INFORMATION REGARDING HOW THIS
MAY IMPACT AREA RIVERS AND STREAMS. WITH THE CLOUDS AND
RAINFALL...IT WILL BE A WARM AND MUGGY NIGHT. MANY AREAS WILL ONLY
DROP INTO THE MID TO UPPER 60S FOR LOWS.
THE MODELS ARE IN GOOD AGREEMENT THAT THE BEST CHANCE FOR
SHOWERS/STORMS LOOKS BETWEEN THE LATE EVENING AND EARLY MORNING
HOURS OF TUESDAY...SO HAVE GONE WITH LIKELY POPS ACROSS MUCH OF
THE AREA DURING THIS TIME PERIOD. THE SFC COLD FRONT WILL PASS
FROM WEST TO EAST DURING THE MORNING HOURS. THIS SHOULD ALLOW
WINDS TO SWITCH AROUND TO THE W-NW AND END THE THREAT OF SHOWERS.
MOST AREAS SHOULD BE RAIN FREE BY THE AFTERNOON HOURS...ALTHOUGH
THE THREAT FOR A SHOWER MAY LINGER IN WESTERN NEW ENGLAND INTO THE
MID AFTN. MAX TEMPS WILL RANGE FROM NEAR 70 IN THE ADIRONDACKS TO
THE MID 80S IN FAR SOUTHEASTERN AREAS...WHERE THE FRONT WILL TAKE
LONGEST TO CROSS.
A LARGE AREA OF HIGH PRESSURE OVER THE MIDWEST WILL SHIFT EASTWARD
TOWARDS THE REGION FOR TOMORROW NIGHT. THIS WILL ALLOW DRY WEATHER
TO RETURN TO THE AREA FOR TOMORROW NIGHT THROUGH THE REMAINDER OF
THE SHORT TERM PERIOD. COOLER AND LESS HUMID WILL MAKE ITS WAY
INTO THE AREA. WITH GOOD RADIATIONAL COOLING EXPECTED...LOWS
TOMORROW NIGHT WILL RANGE FROM THE MID 40S TO THE MID 50S ACROSS
THE AREA WITH CLEARING SKIES. MAX TEMPS ON WED WILL ONLY BE IN THE
70S ACROSS THE AREA...WITH THESE HIGHS BEING A FEW DEGREES BELOW
NORMAL. ANOTHER COOL NIGHT IS EXPECTED FOR WED NIGHT WITH MID 40S
TO MID 50S WITH A NEARLY CLEAR SKY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
RIDGING IS EXPECTED TO DOMINATE LATE IN THE WEEK WITH UNCERTAINTY
IN THE FORECAST GROWING OVER THE WEEKEND. THE GFS AND ECMWF ARE IN
GOOD AGREEMENT KEEPING THE REGION DRY THROUGH SATURDAY WITH RIDGING
ALOFT ACROSS THE NORTHEAST AND HIGH PRESSURE AT THE SURFACE ALONG
THE EAST COAST. ABOVE NORMAL TEMPERATURES ARE ANTICIPATED ESPECIALLY
FRIDAY AND SATURDAY BY AROUND 10 DEGREES.
AFTER LANDFALL ISAAC WILL WEAKENED AS IT MOVES INLAND. SOME MODEL
GUIDANCE INDICATES THE REMNANT MOISTURE FROM ISAAC MAY AFFECT OUR
REGION LATE IN THE WEEKEND INTO EARLY NEXT WEEK. PLEASE REFER TO
PRODUCTS ISSUED BY THE NATIONAL HURRICANE CENTER FOR THE OFFICIAL
FORECAST TRACK OF TROPICAL STORM ISAAC.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE CONTINUES TO SHIFT EAST AND WILL MOVE OFF THE NEW
ENGLAND COAST THIS MORNING. A SLOW MOVING COLD FRONT WILL MOVE
APPROACH AND MOVE THROUGH THE REGION BRINGING INCREASING CHANCES OF
SHOWERS AND PERHAPS SOME THUNDERSTORMS THIS AFTERNOON AND EVENING.
MAINLY VFR CONDITIONS PERSIST EARLY THIS MORNING...EXCEPTION IS AT
KPSF WHERE STRATUS DEVELOP OVER THE LOCAL AREA. THE 11-3.9 MICRON
SATELLITE SHOWS SOME STRATUS DEVELOPING OVER PORTIONS OF THE LOCAL
AREA...EAST CENTRAL NEW YORK AND ADJACENT WESTERN NEW ENGLAND.
WIDESPREAD STRATUS IS ACROSS MUCH OF PA INTO THE SOUTHERN TIER OF NY
AND INTO NORTHEAST NJ. THE STRATUS WILL LIFT/BREAK UP WITH MIXING
AFTER SUNRISE.
CHANCES FOR CONVECTION WILL INCREASE AS THE AFTERNOON PROGRESS INTO
THE EVENING. THERE MAY BE A LULL IN THE ACTIVITY BETWEEN A
PREFRONTAL TROUGH AND THE COLD FRONT. WITH BETTER CHANCES FOR
CONVECTION WITH THE COLD FRONT SINCE WILL HAVE BETTER SUPPORT.
SOUTHERLY FLOW TODAY WITH THE STRONGEST WINDS DURING THE AFTERNOON
WITH SOME GUSTS UP TO AROUND 20 KTS AT KALB DUE TO THE FUNNELING
EFFECT UP THE HUDSON RIVER VALLEY. WINDS WILL LIGHTEN UP DURING THE
EVENING AND REMAIN SOUTHERLY.
OUTLOOK...
TUE...IMPROVING TO VFR. SHRA/TSRA LIKELY IN THE MORNING ESPECIALLY
EARLY.
WED-SAT...VFR.
&&
.FIRE WEATHER...
A COLD FRONT WILL MOVE FROM THE GREAT LAKES TODAY
TOWARDS THE NORTHEAST TONIGHT. THIS WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION...ESPECIALLY DURING THE
OVERNIGHT HOURS. THE FRONT WILL PASS THROUGH THE AREA ON TUESDAY
MORNING...ALLOWING FOR DRIER AND COOLER WEATHER TO MOVE IN FOR THE
MID WEEK PERIOD.
RELATIVE HUMIDITIES WILL ONLY FALL TO ABOUT 50-60 PERCENT THIS
AFTERNOON. RELATIVE HUMIDITIES TONIGHT WITH THE RAIN SHOULD APPROACH
100 PERCENT...THEN AS THE FRONT EXITS TUESDAY...RELATIVE
HUMIDITIES SHOULD DRY OUT TO THE 45 TO 55 PERCENT RANGE. RH VALUES
WILL THEN ONCE AGAIN APPROACH 100 PERCENT TOMORROW NIGHT.
SOUTH TO SOUTHWEST WINDS WILL PICK UP TO 10-15 MPH THIS AFTERNOON.
WEST TO SOUTHWEST WINDS WILL DROP TO AROUND 5 MPH TONIGHT. WINDS
WILL SWITCH TO A WEST TO NORTHWEST WINDS IN THE WAKE OF THE FRONT
FOR TOMORROW AFTERNOON AT SPEEDS OF 10-18 MPH WITH A FEW HIGHER
GUSTS POSSIBLE. WINDS WILL QUICKLY DROP OFF TO NEARLY CALM FOR
TOMORROW NIGHT.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.
NUMEROUS SHOWERS AND SOME EMBEDDED THUNDERSTORMS WILL OCCUR FOR
LATER TODAY THROUGH TONIGHT AND INTO TUESDAY MORNING. WITH PWAT
VALUES AROUND 1.75 INCHES THROUGH THIS PERIOD...SOME HEAVY
DOWNPOURS ARE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. THIS MAY LEAD TO PONDING OF WATER ON AREA ROADWAYS
AND IN AREAS OF POOR DRAINAGE. ALTHOUGH LOCALLY HIGHER AMOUNTS
ARE POSSIBLE...TOTAL AREAL QPF AMOUNTS WILL LIKELY BE AROUND A
HALF TO THREE QUARTERS OF AN INCH. AS A RESULT...WIDESPREAD
FLOODING IS NOT ANTICIPATED...AND DUE TO SUCH DRY ANTECEDENT
CONDITIONS...THIS RAINFALL WILL BE ABSORBED INTO THE GROUND...AND
RUNOFF WILL BE MINIMAL. THIS RAINFALL SHOULD ONLY ALLOW FOR SOME
SMALL RISES ON AREA RIVERS AND STREAMS AT MOST...WITH SOME LARGER
MAINSTEM RIVERS HOLDING STEADY.
MAINLY DRY WEATHER RETURNS TUESDAY AFTERNOON AND SHOULD LAST
THROUGH THE REST OF THE WORK WEEK.
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...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1044 AM CDT MON AUG 27 2012
.DISCUSSION...
ISSUED 1045 AM CDT MON AUG 27 2012
A FEW MINOR ADJUSTMENTS TO THE FORECAST TODAY...LIKE CONTINUE
A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS IN FAR SE IL UNTIL MID
AFTERNOON AND INCREASING CLOUD COVER OVER SE IL INTO EARLY
AFTERNOON. HIGHS MAINLY IN THE MID 80S...THOUGH RANGING FROM THE
LOWER 80S NEAR THE INDIANA BORDER...TO THE UPPER 80S OVER WEST
CENTRAL AND NW IL WHERE MORE SUNSHINE EXPECTED TODAY. WINDS NNW AT
5 TO 15 MPH OVER CENTRAL IL TO SPREAD INTO SE IL TOO THIS
AFTERNOON BEHIND COLD FRONT.
LATE MORNING SURFACE MAP SHOWS WEAK 1015 MB LOW PRESSURE ALONG THE
IN/OH/MI BORDER WITH A COLD FRONT EXTENDING SW THROUGH CENTRAL
INDIANA INTO SE IL NEAR I-70 AND INTO SE MO. ISOLATED SHOWERS
OCCUR ALONG AND AHEAD OF THIS COLD FRONT FROM I-70 SE LATE THIS
MORNING AND SPREADING EASTWARD. HIGH RESOLUTION MODELS BRING COLD
FRONT SE TO THE OHIO RIVER BY 00Z/7 PM TAKING ITS ISOLATED
CONVECTION SE OF LAWRWENCEVILLE BY MID AFTERNOON. HUMID AIRMASS
CURRENTLY IN PLACE OVER CENTRAL/SE IL WITH DEWPOINTS IN THE UPPER
60S AND LOWER 70S CENTRAL IL AND LOW TO MID 70S IN SE IL WILL
GRADUALLY LOWER TO THE LOWER 60S IN CENTRAL IL AND UPPER 60S IN SE
IL BY LATE TODAY WITH NNW WINDS 5-15 MPH. LOW CLOUDS FROM I-55 SE
WILL ALSO GRADUALLY DECREASE FROM NW TO SE DURING THE AFTERNOON AS
SKIES BECOME MOSTLY SUNNY...THOUGH STAYING CLOUDIER LONGER IN SE IL.
KH
&&
.AVIATION...
ISSUED 623 AM CDT MON AUG 27 2012
MAIN CONCERN AVIATION-WISE IS THE NEXT FEW HOURS. FAIRLY
WIDESPREAD MVFR/IFR CEILINGS OVER THE NORTHERN HALF OF ILLINOIS
INTO ADJACENT PARTS OF MISSOURI AND IOWA. HRRR CEILING GUIDANCE
SHOWING THIS SHOULD RAPIDLY BREAK UP BETWEEN ABOUT 14-17Z...
ALTHOUGH AREAS FROM KPIA-KCMI WHICH HAD HEAVY RAINFALL RECENTLY
MAY TAKE TOWARD THE END OF THAT TIME RANGE. HAVE SEEN SOME BRIEF
VISIBILITY REDUCTIONS BUT FOR THE MOST PART...THE DENSE FOG HAS
REMAINED TO THE NORTHWEST IN AREAS THAT CLEARED OUT FOR A TIME
EARLIER IN THE NIGHT. ONCE THE CLOUDS BREAK UP BY LATE MORNING...
VFR CONDITIONS SHOULD PREVAIL THE REMAINDER OF THE TAF PERIOD. THE
ONLY EXCEPTION WOULD BE SOME PATCHY FOG THAT MAY FORM LATE
TONIGHT AS WINDS BECOME LIGHT...WITH THE PRIMARY CONCERN IN AREAS
THAT HAD HEAVY RAIN. AT THE MOMENT...WILL ONLY MENTION THIS AT KCMI.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 320 AM CDT MON AUG 27 2012
WEAK FLOW ACROSS THE MIDWEST THIS MORNING...WITH PRECIP ALONG A
WEAKENING BOUNDARY AT THE SFC AS THE FORWARD PROGRESSION SLOWS AS
ITS APPROACHING THE OHIO RIVER VALLEY. LINGERING PRECIP IN SRN
TIER OF CWA THIS MORNING...AND FIRST ISSUE FOR THE FORECAST IS THE
CLEARING OF THIS RAIN TODAY...AND ITS IMPACT ON TEMPERATURES THIS
AFTERNOON. BEYOND THAT AND THE POTENTIAL FOR FOG IN THE WAKE OF
ALL OF SUNDAYS RAINFALL...THE MAIN ISSUE FOR THE FORECAST IS IN
THE EXTENDED WITH REGARDS TO THE REMNANTS OF ISAAC AND POTENTIAL
MOISTURE TRANSPORT.
SHORT TERM...TODAY AND TOMORROW...
SLOWING BOUNDARY KEEPING POPS IN FOR THIS MORNING...MAINLY ALONG
AND SOUTH OF INTERSTATE 70 FOR THE BEST POPS. MOST MODELS SLIGHTLY
OVERDONE IN THE OVERNIGHT PRECIP...INCLUDING THE HIGH RES MODELS
LIKE THE 4KM WRF WHICH EVEN ANTICIPATED THE SLIGHT STRENGTHENING
OF SOME OF THE RAINFALL ALONG AND SOUTH OF INTERSTATE 70 AFTER
06Z. HOWEVER...EVEN SO...MOST MODELS CLEARING AFTER 18Z AND WILL
KEEP THE GRIDS SIMPLE AND FOLLOW THAT TREND. CLOUDINESS IN THE SE
WILL KEEP THE TEMPS A BIT LOWER THIS AFTERNOON...WHEREAS THE NW
AND WEST WILL HAVE A CHANCE TO MAX OUT IN THE UPPER 80S. REAL
QUESTION FOR THE SHORT TERM WILL BE THE AMOUNT OF MIXING THAT GETS
INTO THE REGION BY THIS EVENING. MUCH DRIER AIR IS CONTAINED
BEHIND THE SECONDARY BOUNDARY WELL TO THE NW FROM SD TO SRN MN.
NAM BRINGS IN AFTERNOON CROSSOVER TEMPS DOWN INTO THE 50S...AND THINK
THAT IS HIGHLY UNLIKELY CONSIDERING THE SOAKING OF YESTERDAY AND
THE SLOWER RETREAT OF THE CLOUDS TODAY. PUTTING IN PATCHY FOG FOR
TOMORROW EARLY MORNING AT THE VERY LEAST...AND WILL HAVE TO KEEP
AN EYE ON DWPTS FOR THIS AFTERNOON AS TO THE EXPANSE OF FOG
POTENTIAL.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
RAIN POTENTIAL IN THE EXTENDED IS ENTIRELY BASED ON THE
TRACK/MOISTURE TRANSPORT FROM TS ISAAC AND WHERE IT MAKES
LANDFALL. AS A RESULT...THE POPS IN THE EXTENDED ARE A BIT
PRECARIOUS. LOOSELY STATED...CHANCES EXTEND FROM FRIDAY THROUGH
SUNDAY...WITH THE BEST CHANCES MAINLY IN THE SOUTHERN HALF OF THE
STATE. THAT BEING SAID...THINK THE GFS AND TO SOME EXTENT THE 00Z
ECMWF ARE A BIG HASTY IN BRINGING THE SYSTEM UP HERE SO QUICKLY.
MOVING THE TROPICAL SYSTEM INTO THE RATHER EXPANSIVE RIDGE IS
LIKELY TO SLOW IT SOMEWHAT...AND DISRUPT THE MOISTURE ADVECTION
WITH THE VOLUME OF DRY AIR AVAILABLE TO EAT AWAY AT THE RH.
HOWEVER...THE GFS MAINTAINS A CYCLONE DYNAMIC AND SHAPE EVEN TO
THE QPF/CONVECTIVE FIELDS. CONCERNED THAT ITS OVERDONE A BIT...AND
TRYING TO SCALE BACK THE MASSIVE POPS. NOT ONLY ARE THE
OPERATIONAL MODELS TREATING A TROPICAL...THEN EXTRA TROPICAL
SYSTEM LIKE A MID LATITUDE CYCLONE...BUT THERE IS SO MUCH SPREAD IN
THE LANDFALL FORECASTS/TRACKS FOR THE FORECAST THAT CALLING
CERTAINTY AT THIS POINT IS A BIT OPTIMISTIC. FORECAST IS
RELATIVELY CONSERVATIVE...WITH A PUSH FOR A SLIGHTLY DELAYED
PRECIP EVENT SHOULD THE MOISTURE MATERIALIZE.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
623 AM CDT MON AUG 27 2012
.DISCUSSION...
ISSUED 320 AM CDT MON AUG 27 2012
WEAK FLOW ACROSS THE MIDWEST THIS MORNING...WITH PRECIP ALONG A
WEAKENING BOUNDARY AT THE SFC AS THE FORWARD PROGRESSION SLOWS AS
ITS APPROACHING THE OHIO RIVER VALLEY. LINGERING PRECIP IN SRN
TIER OF CWA THIS MORNING...AND FIRST ISSUE FOR THE FORECAST IS THE
CLEARING OF THIS RAIN TODAY...AND ITS IMPACT ON TEMPERATURES THIS
AFTERNOON. BEYOND THAT AND THE POTENTIAL FOR FOG IN THE WAKE OF
ALL OF SUNDAYS RAINFALL...THE MAIN ISSUE FOR THE FORECAST IS IN
THE EXTENDED WITH REGARDS TO THE REMNANTS OF ISAAC AND POTENTIAL
MOISTURE TRANSPORT.
SHORT TERM...TODAY AND TOMORROW...
SLOWING BOUNDARY KEEPING POPS IN FOR THIS MORNING...MAINLY ALONG
AND SOUTH OF INTERSTATE 70 FOR THE BEST POPS. MOST MODELS SLIGHTLY
OVERDONE IN THE OVERNIGHT PRECIP...INCLUDING THE HIGH RES MODELS
LIKE THE 4KM WRF WHICH EVEN ANTICIPATED THE SLIGHT STRENGTHENING
OF SOME OF THE RAINFALL ALONG AND SOUTH OF INTERSTATE 70 AFTER
06Z. HOWEVER...EVEN SO...MOST MODELS CLEARING AFTER 18Z AND WILL
KEEP THE GRIDS SIMPLE AND FOLLOW THAT TREND. CLOUDINESS IN THE SE
WILL KEEP THE TEMPS A BIT LOWER THIS AFTERNOON...WHEREAS THE NW
AND WEST WILL HAVE A CHANCE TO MAX OUT IN THE UPPER 80S. REAL
QUESTION FOR THE SHORT TERM WILL BE THE AMOUNT OF MIXING THAT GETS
INTO THE REGION BY THIS EVENING. MUCH DRIER AIR IS CONTAINED
BEHIND THE SECONDARY BOUNDARY WELL TO THE NW FROM SD TO SRN MN.
NAM BRINGS IN AFTERNOON CROSSOVER TEMPS DOWN INTO THE 50S...AND THINK
THAT IS HIGHLY UNLIKELY CONSIDERING THE SOAKING OF YESTERDAY AND
THE SLOWER RETREAT OF THE CLOUDS TODAY. PUTTING IN PATCHY FOG FOR
TOMORROW EARLY MORNING AT THE VERY LEAST...AND WILL HAVE TO KEEP
AN EYE ON DWPTS FOR THIS AFTERNOON AS TO THE EXPANSE OF FOG
POTENTIAL.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
RAIN POTENTIAL IN THE EXTENDED IS ENTIRELY BASED ON THE
TRACK/MOISTURE TRANSPORT FROM TS ISAAC AND WHERE IT MAKES
LANDFALL. AS A RESULT...THE POPS IN THE EXTENDED ARE A BIT
PRECARIOUS. LOOSELY STATED...CHANCES EXTEND FROM FRIDAY THROUGH
SUNDAY...WITH THE BEST CHANCES MAINLY IN THE SOUTHERN HALF OF THE
STATE. THAT BEING SAID...THINK THE GFS AND TO SOME EXTENT THE 00Z
ECMWF ARE A BIG HASTY IN BRINGING THE SYSTEM UP HERE SO QUICKLY.
MOVING THE TROPICAL SYSTEM INTO THE RATHER EXPANSIVE RIDGE IS
LIKELY TO SLOW IT SOMEWHAT...AND DISRUPT THE MOISTURE ADVECTION
WITH THE VOLUME OF DRY AIR AVAILABLE TO EAT AWAY AT THE RH.
HOWEVER...THE GFS MAINTAINS A CYCLONE DYNAMIC AND SHAPE EVEN TO
THE QPF/CONVECTIVE FIELDS. CONCERNED THAT ITS OVERDONE A BIT...AND
TRYING TO SCALE BACK THE MASSIVE POPS. NOT ONLY ARE THE
OPERATIONAL MODELS TREATING A TROPICAL...THEN EXTRA TROPICAL
SYSTEM LIKE A MID LATITUDE CYCLONE...BUT THERE IS SO MUCH SPREAD IN
THE LANDFALL FORECASTS/TRACKS FOR THE FORECAST THAT CALLING
CERTAINTY AT THIS POINT IS A BIT OPTIMISTIC. FORECAST IS
RELATIVELY CONSERVATIVE...WITH A PUSH FOR A SLIGHTLY DELAYED
PRECIP EVENT SHOULD THE MOISTURE MATERIALIZE.
HJS
&&
.AVIATION...
ISSUED 623 AM CDT MON AUG 27 2012
MAIN CONCERN AVIATION-WISE IS THE NEXT FEW HOURS. FAIRLY
WIDESPREAD MVFR/IFR CEILINGS OVER THE NORTHERN HALF OF ILLINOIS
INTO ADJACENT PARTS OF MISSOURI AND IOWA. HRRR CEILING GUIDANCE
SHOWING THIS SHOULD RAPIDLY BREAK UP BETWEEN ABOUT 14-17Z...
ALTHOUGH AREAS FROM KPIA-KCMI WHICH HAD HEAVY RAINFALL RECENTLY
MAY TAKE TOWARD THE END OF THAT TIME RANGE. HAVE SEEN SOME BRIEF
VISIBILITY REDUCTIONS BUT FOR THE MOST PART...THE DENSE FOG HAS
REMAINED TO THE NORTHWEST IN AREAS THAT CLEARED OUT FOR A TIME
EARLIER IN THE NIGHT. ONCE THE CLOUDS BREAK UP BY LATE MORNING...
VFR CONDITIONS SHOULD PREVAIL THE REMAINDER OF THE TAF PERIOD. THE
ONLY EXCEPTION WOULD BE SOME PATCHY FOG THAT MAY FORM LATE
TONIGHT AS WINDS BECOME LIGHT...WITH THE PRIMARY CONCERN IN AREAS
THAT HAD HEAVY RAIN. AT THE MOMENT...WILL ONLY MENTION THIS AT KCMI.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1038 AM EDT MON AUG 27 2012
.Forecast Update...
Issued at 1035 AM EDT Mon Aug 27 2012
The cold front is currently situated along a line from northeastern
Indiana to southern Illinois to southeastern Missouri. Showers have
begun to move into our southern Indiana counties this morning with
more scattered development to the west. Currently there is little
lightning associated with this convection, so will continue to
mention scattered showers today with isolated thunderstorms for now.
Minor tweaks were made to the current grids and expected pop trends,
but percentages will remain in the same range. Updates are already
out.
&&
.Short Term (Today - Tuesday)...
Issued at 250 AM EDT Mon Aug 27 2012
A sfc cold front and upper trough stretched from the Great Lakes
through Illinois to Oklahoma as of 630Z this morning. Along this
front, showers with embedded t-storms were noted in radar imagery.
These features along with convection will continue to move eastward
into our area today. A few showers have already been noted in
Dubois County, Indiana early this morning. We can expect to see
continued isld activity through sunrise. After sunrise, the line of
scattered showers with some t-storms will make its way into our NW
forecast area and continue to travel ESE throughout the day. Thus,
most locations over southern Indiana and central Kentucky can expect
to see at least a brief shower at some point during the day and
tonight. However, QPF amounts should be under a tenth of an inch
for most locations. A few locations that see a t-storm may get a
quarter inch of rain. Any t-storms that develop should be garden
variety type storms with the main threats being locally heavy
rainfall, brief gusty winds, and cloud to ground lightning.
The front should pass through the area this evening slowly ending
any left over shower activity from NW to SE tonight over most
locations. The front does look to stall over south central KY Tues
morning so will keep low POPs in over this region through 18Z Tues.
Temperatures should range from the mid 80s over southern Indiana to
around 90 over south central KY for highs today. The hotter temps
will occur in locations over the south that will be the last to
receive rain/clouds from the approaching front/trough. Lows tonight
should be in the mid 60s to around 70. If southern Indiana or
northern KY clear out quick enough behind the front, light fog may
be possible tonight. For Tues, expect gradually clearing skies from
N to S with highs in the mid to upper 80s.
.Long Term (Tuesday Night - Sunday)...
Issued at 250 AM EDT Mon Aug 27 2012
Tropical cyclone Isaac is forecast to be entering the north central
Gulf coast at the start of this period, which should keep all
moisture south of the region Tuesday night through at least late
afternoon Thursday. Beyond that, models continue to have trouble
dealing with where the remnants of Isaac will end up. Most of the
models continue to show a narrow ridge getting squeezed into the
Midwest over the top of these remnants, in a Rex block fashion. This
would mean we can expect some slower movement with this system.
That small ridge looks to get forced into the Mid Atlantic region
Friday night on, which should allow the moisture to surge in here
and bring in better rain chances. Still lower than normal confidence
in this solution given the potential for a slower moving storm than
what the models are showing. The AllBlend solution for pops actually
looks pretty good with this scenario...having low end chances
Thursday night, then going to the 50 percent range Saturday into
Sunday. Keep your fingers crossed that we can get some of this rain
to help the drought situation.
Dry air over the region early on will mean a chance for the normally
cooler spots to get down to around 60 Wednesday and Thursday
mornings. Northerly winds will combat otherwise clear skies for
highs each day, so thinking readings will stay in the mid/upper 80s.
Cloud cover and moisture will limit the diurnal range the rest of
the period, with highs in the 80s and lows around 70.
&&
.Aviation (12Z TAF issuance)...
Issued at 655 AM EDT Mon Aug 27 2012
Main TAF concerns will be arrival of showers into the TAF sites this
afternoon. Convection along and ahead of a sfc cold front and upper
level trough will be entering the area this afternoon. 8Z RAP and
6Z NAM4 have a good handle on current convection and sfc features so
will lean toward these models. With these solns in mind, delayed
VCSH in the TAFs till 16Z at SDF, 19Z at LEX, and 21Z at BWG.
Models indicate a line of scattered garden variety showers with some
embedded t-storms. Thunder does not look likely for the TAFs at
this point. Winds should remain calm or SSE through the early
morning hours, then veer to the SWW for late morning and early
afternoon as the front approaches. The fropa looks to occur this
evening with winds shifting to the NWN after 3-4Z and shower chances
ending. Light br or low cigs may occur close to the front Tues
morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........EER
Short Term.......AMS
Long Term........RJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
655 AM EDT MON AUG 27 2012
...Updated Aviation Discussion...
.Forecast Update...
Issued at 635 AM EDT Mon Aug 27 2012
Downgraded t-storm chances to isld today. The 6Z NAM and 8Z RAP
really depict what`s left of convection along the front falling
apart throughout the day as it crosses our area. Was on the fence
about isld or sct t-storm chances for the 4am forecast package.
Upstream obs and latest model guidance points toward only isld
storms if that today so will update the forecast.
&&
.Short Term (Today - Tuesday)...
Issued at 250 AM EDT Mon Aug 27 2012
A sfc cold front and upper trough stretched from the Great Lakes
through Illinois to Oklahoma as of 630Z this morning. Along this
front, showers with embedded t-storms were noted in radar imagery.
These features along with convection will continue to move eastward
into our area today. A few showers have already been noted in
Dubois County, Indiana early this morning. We can expect to see
continued isld activity through sunrise. After sunrise, the line of
scattered showers with some t-storms will make its way into our NW
forecast area and continue to travel ESE throughout the day. Thus,
most locations over southern Indiana and central Kentucky can expect
to see at least a brief shower at some point during the day and
tonight. However, QPF amounts should be under a tenth of an inch
for most locations. A few locations that see a t-storm may get a
quarter inch of rain. Any t-storms that develop should be garden
variety type storms with the main threats being locally heavy
rainfall, brief gusty winds, and cloud to ground lightning.
The front should pass through the area this evening slowly ending
any left over shower activity from NW to SE tonight over most
locations. The front does look to stall over south central KY Tues
morning so will keep low POPs in over this region through 18Z Tues.
Temperatures should range from the mid 80s over southern Indiana to
around 90 over south central KY for highs today. The hotter temps
will occur in locations over the south that will be the last to
receive rain/clouds from the approaching front/trough. Lows tonight
should be in the mid 60s to around 70. If southern Indiana or
northern KY clear out quick enough behind the front, light fog may
be possible tonight. For Tues, expect gradually clearing skies from
N to S with highs in the mid to upper 80s.
.Long Term (Tuesday Night - Sunday)...
Issued at 250 AM EDT Mon Aug 27 2012
Tropical cyclone Isaac is forecast to be entering the north central
Gulf coast at the start of this period, which should keep all
moisture south of the region Tuesday night through at least late
afternoon Thursday. Beyond that, models continue to have trouble
dealing with where the remnants of Isaac will end up. Most of the
models continue to show a narrow ridge getting squeezed into the
Midwest over the top of these remnants, in a Rex block fashion. This
would mean we can expect some slower movement with this system.
That small ridge looks to get forced into the Mid Atlantic region
Friday night on, which should allow the moisture to surge in here
and bring in better rain chances. Still lower than normal confidence
in this solution given the potential for a slower moving storm than
what the models are showing. The AllBlend solution for pops actually
looks pretty good with this scenario...having low end chances
Thursday night, then going to the 50 percent range Saturday into
Sunday. Keep your fingers crossed that we can get some of this rain
to help the drought situation.
Dry air over the region early on will mean a chance for the normally
cooler spots to get down to around 60 Wednesday and Thursday
mornings. Northerly winds will combat otherwise clear skies for
highs each day, so thinking readings will stay in the mid/upper 80s.
Cloud cover and moisture will limit the diurnal range the rest of
the period, with highs in the 80s and lows around 70.
&&
.Aviation (12Z TAF issuance)...
Issued at 655 AM EDT Mon Aug 27 2012
Main TAF concerns will be arrival of showers into the TAF sites this
afternoon. Convection along and ahead of a sfc cold front and upper
level trough will be entering the area this afternoon. 8Z RAP and
6Z NAM4 have a good handle on current convection and sfc features so
will lean toward these models. With these solns in mind, delayed
VCSH in the TAFs till 16Z at SDF, 19Z at LEX, and 21Z at BWG.
Models indicate a line of scattered garden variety showers with some
embedded t-storms. Thunder does not look likely for the TAFs at
this point. Winds should remain calm or SSE through the early
morning hours, then veer to the SWW for late morning and early
afternoon as the front approaches. The fropa looks to occur this
evening with winds shifting to the NWN after 3-4Z and shower chances
ending. Light br or low cigs may occur close to the front Tues
morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......AMS
Long Term........RJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1048 AM EDT MON AUG 27 2012
.UPDATE...
ISSUED AT 1049 AM EDT MON AUG 27 2012
12Z SURFACE ANALYSIS SHOWS THE UPPER PENINSULA IN THE WAKE OF A COLD
FRONT THAT MOVED ACROSS THE REGION DURING THE OVERNIGHT HOURS...AND
WAS NOW LOCATED FROM NORTHEAST ONTARIO WEST-SOUTHWEST ACROSS THE TIP
OF THE LOWER PENINSULA AND INTO CENTRAL WISCONSIN...WEAKLY CYCLONIC
PRESSURE PATTERN ACROSS THE REGION THIS MORNING. FRONT WAS
SUPPORTED ALOFT BY AN ELONGATED PV ANOMALY...WITH WATER VAPOR
IMAGERY SHOWING A BETTER DEFINED DISTURBANCE HEADING EAST-SOUTHEAST
OVER NORTHWEST ONTARIO. CLOUDS AND SOME SHOWERS ONGOING NORTH AND
NORTHWEST OF LAKE SUPERIOR WITH THIS FEATURE. SKIES ACROSS
WESTERN/CENTRAL UPPER ARE MAINLY CLEAR TO START WITH JUST A PATCH OF
AC EAST OF THE KEWEENAW.
NORTHWEST ONTARIO SHORT WAVE TROUGH FORECAST TO SLIDE INTO WESTERN
UPPER LATER THIS AFTERNOON...BUT THE ENVIRONMENT AHEAD OF THIS
FEATURE IS NOT PARTICULARLY MOIST...AS MUCH OF THE MID/UPPER LEVEL
MOISTURE IS TO THE NORTH OF THE MAIN VORTICITY CENTER. SO OUTSIDE
OF A LITTLE DIURNALLY DRIVEN CU DEVELOPMENT...SHOULD BE A NICE
AFTERNOON. 12Z GRB SOUNDING HAD A NICE MIXED RESIDUAL LAYER BETWEEN
950-780MB...MIXING TO THIS POINT YIELDS AN AFTERNOON HIGH OF 79F
WHICH CURRENT FORECAST SEEMS TO HAVE WELL IN HAND. SO NO BIG
CHANGES IN THE FORECAST AT THIS POINT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 738 AM EDT MON AUG 27 2012
WITH HIGH PRESSURE AND DRY AIR BUILDING OVER THE REGION...VFR
CONDITIONS ARE EXPECTED THROUGH THE FCST PERIOD. A PERIOD OF BKN
CLOUDS TONIGHT AT CMX/SAW ASSOCIATED WITH COLDER AIR SLIDING IN
FROM NORTH IS EXPECTED TO REMAIN ABOVE 3K FT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LS...NONE.
LM...NONE.
&&
$$
UPDATE...JPB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT MON AUG 27 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
MOISTURE FOCUSED FARTHER S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 738 AM EDT MON AUG 27 2012
WITH HIGH PRESSURE AND DRY AIR BUILDING OVER THE REGION...VFR
CONDITIONS ARE EXPECTED THROUGH THE FCST PERIOD. A PERIOD OF BKN
CLOUDS TONIGHT AT CMX/SAW ASSOCIATED WITH COLDER AIR SLIDING IN
FROM NORTH IS EXPECTED TO REMAIN ABOVE 3K FT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
ACROSS LAKE SUPERIOR LATE FRIDAY BEHIND THE TROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
736 AM CDT MON AUG 27 2012
.UPDATE...JUST COMPLETED AN UPDATE MAINLY TO ADD 20-30 PERCENT
SHOWER/ISOLATED STORM COVERAGE TO THE MAJORITY OF SOUTH CENTRAL
NEBRASKA THROUGH 15Z...WHICH MAY NOT BE LONG ENOUGH BUT ITS A
START. SINCE 11Z OR SO...ELEVATED SHOWERS AND A FEW STORMS HAVE
MOVED INTO OR DEVELOPED OVER MAINLY THE NORTHWEST QUADRANT OF THE
CWA. ALTHOUGH THIS ACTIVITY WAS NOT WELL-ANTICIPATED EVEN 12 HOURS
AGO...THE LATEST TRENDS FROM THE RAP MODEL INDICATE A PRONOUNCED
THETA-E GRADIENT EVIDENT ACROSS THE CWA AT 700MB...WITH MODEST
THETA-E ADVECTION/MID LEVEL CONVERGENCE SPARKING THIS FAIRLY
CLASSIC CASE OF SUNRISE SURPRISE ACTIVITY. THE JURY IS OUT ON HOW
LONG SOME OF THIS PRECIP MIGHT LAST...BUT THE LATEST HRRR KEEPS AT
LEAST SOMETHING GOING INTO THE EARLY AFTERNOON HOURS...SO WILL
DEFER TO ONCOMING DAY SHIFT TO EXTEND THESE POPS BEYOND 15Z IF
NECESSARY. NOT EXPECTING ANYTHING SEVERE...ALTHOUGH SUPPOSE SOME
PEA SIZE HAIL IS NOT OUT OF THE QUESTION WITH MUCAPE POTENTIALLY
IN EXCESS OF 500 J/KG. AS FOR FOG TRENDS...A FEW ISOLATED POCKETS
OF DENSE FOG HAVE BEEN REPORTED IN THE EASTERN CWA...BUT NOWHERE
NEAR WIDESPREAD ENOUGH TO CONSIDER AN ADVISORY WITH MOST AREAS
WELL ABOVE 1 MILE. DID HOWEVER ADD SOME 1 MILE OR LESS WORDING TO
THE ZONE FORECAST TO ACKNOWLEDGE THE SPOTTY LOWER VISIBILITIES OUT
THERE FOR THE NEXT FEW HOURS. NO OTHER CHANGES MADE AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 639 AM CDT MON AUG 27 2012/
AVIATION...12Z KGRI TAF. ALTHOUGH VFR VISIBILITY/CEILING AND
PRECIPITATION-FREE CONDITIONS ARE FORECAST THROUGH THE VAST
MAJORITY OF THE PERIOD...THE FIRST FEW HOURS RIGHT AWAY THIS
MORNING COULD POSE A FEW ISSUES. FIRST OFF...WILL CONTINUE TO
CARRY A TEMPO GROUP THROUGH 14Z TO COVER THE POSSIBILITY OF A
BRIEF MVFR VISIBILITY RESTRICTION...AS LIGHT FOG HAS BEEN REPORTED
AT NEARBY STATIONS THIS MORNING. SECONDLY...A SOMEWHAT UNEXPECTED
NARROW CORRIDOR OF SHOWERS/WEAK THUNDERSTORMS IS CURRENTLY LOCATED
WITHIN 40 MILES WEST-NORTHWEST OF KGRI...AND IS SHOWING SOME SIGNS
OF WORKING EAST TOWARD THE TERMINAL. FOR NOW...WILL INTRODUCE A
VICINITY THUNDERSTORM MENTION THROUGH 15Z ALTHOUGH ANY STORMS THAT
MIGHT AFFECT THE TERMINAL SHOULD PRODUCE LITTLE MORE THAN A BRIEF
DOWNPOUR. BEYOND THESE INITIAL CONCERNS THIS MORNING...THE TIME
FRAME BETWEEN LATE THIS MORNING THROUGH THE OVERNIGHT HOURS
SHOULD BE PRECIPITATION AND FOG-FREE...AS SOUTHERLY SUSTAINED
BREEZES AVERAGE NO MORE THAN 10-12KT. AT THIS TIME...ANY LATE
AFTERNOON/EVENING THUNDERSTORMS ARE EXPECTED TO FOCUS AT LEAST 100
MILES NORTHWEST OF KGRI.
PREV DISCUSSION... /ISSUED 547 AM CDT MON AUG 27 2012/
SHORT TERM...TODAY THROUGH 12Z THURSDAY.
BIGGEST CHALLENGE WILL BE POSSIBLE SHOWERS AND THUNDERSTORMS FOR
PART OF THE AREA THIS MORNING.
GENERAL SCENARIO OF THE UPPER RIDGE BUILDING INTO THE REGION IS THE
DOMINANT FEATURE FOR OUR AREA.
A THIN RIBBON OF CONVECTION IS BEGINNING TO DEVELOP JUST TO THE
NORTHWEST OF THE CWA. THIS APPEARS TO BE OCCURRING FROM SOME WEAK
THETA-E ADVECTION IN MID-LEVELS. ORIGINALLY I THOUGHT THAT PERHAPS
THETA-E ADVECTION HAD SUBSIDED ENOUGH SO THAT THE REGION WOULD BE
DRY. EARLIER CONVECTION ACROSS PARTS OF WESTERN AND CENTRAL NEBRASKA
OVERNIGHT LAST NIGHT DIED OUT AS IT ENTERED OUR CWA...BUT THIS NEW
BATCH SEEMS TO BE WAXING...AND PERHAPS STRENGTHENING AND BUILDING
TOWARD OUR CWA. THIS WILL NEED TO BE MONITORED THIS MORNING FOR A
POTENTIAL UPDATE. SEVERE WEATHER DOES NOT APPEAR TO BE AN ISSUE IN
THIS CASE. THIS SHOULD DIE OFF BY MID-MORNING...WHEREVER IT DECIDES
TO END UP.
THE MORNING FOG...ESPECIALLY IN THE EASTERN CWA...SHOULD BURN OFF
SHORTLY AFTER SUNRISE AS SUBSIDENCE IS SIGNIFICANT.
ANOTHER PROBLEM IN THE SHORT TERM IS THE POTENTIAL FOR ELEVATED FIRE
DANGER...ESPECIALLY IN WESTERN AREAS OF THE CWA WITH RELATIVE
HUMIDITY DECREASING TO NEAR 20 PERCENT AND SUSTAINED WIND SPEEDS
POSSIBLY GETTING CLOSE TO 20 MPH. COULD BE A CLOSE ONE ON EITHER DAY.
MADE MINOR TWEAKS TO TEMPERATURE AND DEWPOINTS USING RECENT
VERIFICATION DATA AS A TOOL. GENERALLY COOLED DOWN MAXIMUM
TEMPERATURES A TAD FOR TUESDAY AND WEDNESDAY.
LONG TERM...THURSDAY DAYTIME THROUGH SUNDAY DAYTIME. OVERALL...VERY
LITTLE CHANGE MADE TO THESE 4 DAYS FROM PREVIOUS FORECAST...WHICH
APPEAR TO BE HIGHLIGHTED BY AT LEAST SLIGHTLY ABOVE NORMAL TEMPS AND
DRY CONDITIONS. THAT BEING SAID...AT LEAST A SLIGHT RAIN MENTION MAY
ULTIMATELY PROVE NECESSARY FOR THE SAT NIGHT/SUNDAY TIME FRAME...BUT
WITH THIS POSSIBILITY STILL BEING 5-6 DAYS OUT WILL MAINTAIN THE
PRECIP-FREE MENTION FOR NOW. LOW TEMPERATURES THROUGH THIS PERIOD
ARE FORECAST TO AVERAGE LOW-MID 60S.
STARTING OFF THURSDAY/THURSDAY NIGHT...00Z ECMWF/GFS RUNS ARE IN
DECENT AGREEMENT ON THE BIG PICTURE ALOFT...WITH A BROAD
WEST-SOUTHWEST TO EAST-NORTHEAST ORIENTED RIDGE DOMINATING THE LOCAL
AREA AND IN THEORY KEEPING THINGS CAPPED OFF TO CONVECTION. THE
CENTRAL PLAINS LIES BETWEEN A TROUGH OVER THE NORTHERN
ROCKIES/PACIFIC NORTHWEST...AND THE REMNANTS OF TROPICAL SYSTEM
ISAAC WHICH ARE GENERALLY PROGGED TO TRACK FROM THE SOUTHERN LA/MS
AREA THURSDAY MORNING TO ARKANSAS AND VICINITY BY FRIDAY MORNING.
BACK HOME...THE DAYTIME HOURS THURSDAY COULD BE A TOUCH BREEZY
ESPECIALLY ACROSS THE NORTHWEST 1/2 OF THE CWA...AS A WEAK LOW
PRESSURE SYSTEM PASSING OFF TO THE NORTH KEEPS SOUTH/SOUTHWEST
SURFACE FLOW IN PLACE. FOR HIGH TEMPS...KEPT THE ENTIRE CWA IN THE
LOW-MID 90S. AT LEAST FOR NOW...HAVE MINIMUM AFTERNOON RELATIVE
HUMIDITY VALUES ABOVE 20 PERCENT ALL AREAS...BUT HAVE SEVERAL FAR
WESTERN COUNTIES AS LOW AS THE MID 20S...SO AT LEAST SOME ELEVATED
FIRE DANGER NOT OUT OF THE QUESTION. WITH MORE IMMEDIATE AND
POTENTIALLY ELEVATED FIRE DANGER ISSUES IN THE SHORT TERM PERIOD
TUESDAY-WEDNESDAY...WILL HOLD OFF ON ANY FIRE WEATHER MENTION FOR
THURSDAY IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME.
FRIDAY/FRIDAY NIGHT...KEPT THE DRY FORECAST GOING...AS ANY NORTHERN
STREAM DISTURBANCES REMAIN WELL OFF TO THE NORTH/NORTHWEST OF THE
AREA...WHILE THE ECMWF/GFS CONSENSUS FOR THE ISAAC REMNANTS IS TO
BRING THEM UP INTO MISSOURI AND VICINITY...KEEPING ANY ASSOCIATED
PRECIP NO CLOSER TO THE CWA THAN FAR EASTERN KS IF THIS TRACK HOLDS.
WITH A BIT WEAKER SURFACE GRADIENT VERSUS THURSDAY...NOT EXPECTING
ELEVATED FIRE DANGER TO BE MUCH OF AN ISSUE...BUT KEPT HIGH TEMPS
SEVERAL DEGREES ABOVE NORMAL WITH OF THE CWA IN THE 90-92 RANGE.
SATURDAY/SAT NIGHT...ANTICIPATE THE BROAD RIDGE OVER THE CWA TO
FLATTEN A BIT...AS FLOW TURNS MORE ZONAL IN RESPONSE TO A FAIRLY
VIGOROUS SHORTWAVE CROSSING FAR SOUTH CENTRAL CANADA.
MEANWHILE...ISAAC REMNANTS ARE STILL EXPECTED TO BE A NON-ISSUE
LOCALLY AS THEY ARE SHUNTED NORTHEAST ACROSS THE IL/IN AREA. WHILE
CONFIDENCE IS REASONABLY HIGH IN A DRY DAYTIME PERIOD...COULD
FORESEE SOME SLIGHT POPS EVENTUALLY NECESSITATED FOR SAT NIGHT IN
PARTS OF THE CWA AS A WEAK SHORTWAVE APPROACHES FROM THE WEST. AGAIN
VERY LITTLE CHANGE TO HIGH TEMPS WITH 89-92 PROGGED CWA-WIDE.
FINALLY FOR SUNDAY DAYTIME...HAVE KEPT IT VOID OF SLIGHT POPS FOR
NOW...BUT THIS MAY NOT HOLD MUCH LONGER IF THE ECMWF/GFS CONTINUE TO
ADVERTISE THE GENERAL SCENARIO OF THE LOCAL AREA BEING BRUSHED BY A
PASSING SHORTWAVE TRACKING THROUGH THE NORTHERN PLAINS/UPPER MS
VALLEY REGION...WHICH PUSHES A FAIRLY WEAK COLD FRONT THROUGH THE
CWA. KEPT HIGHS UPPER 80S MOST NEB ZONES/NEAR 90 KS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/AVIATION/LONG TERM...PFANNKUCH
SHORT TERM...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
625 AM EDT MON AUG 27 2012
.SYNOPSIS...
ANOTHER WARM DAY IS EXPECTED TODAY AS TEMPERATURES WARM AHEAD OF A
STRONG COLD FRONT THAT WILL PASS LATE THIS AFTERNOON INTO THIS
EVENING. AS THIS FEATURE PASSES...SHOWERS AND ISOLATED TO SCATTERED
THUNDERSTORMS WILL MOVE ACROSS MUCH OF CENTRAL NEW YORK AND
NORTHEAST PENNSYLVANIA. FOLLOWING THE FRONTAL PASSAGE...HIGH
PRESSURE AND DRY CONDITIONS WILL RETURN TO THE AREA WITH BELOW
NORMAL TEMPERATURES EXPECTED THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
625 AM UPDATE...
INCREASED POPS TO AN ISOLATED MENTION FOR THE NEXT FEW HRS FROM
THE LOWER WYOMING VLY NORTH THROUGH THE EASTERN SOUTHERN TIER AND
UPPER SUSQUEHANNA BASIN. ACROSS THESE AREAS...WEAK SHOWERS HAVE
FORMED AHEAD OF THE UPPER WAVE LIFTING NORTH FROM THE CENTRAL
MID-ATLANTIC. THE HRRR SHOWS THIS ACTIVITY GRADUALLY DIMINISHING
AS THE LOWER STRATUS DECK BEGINS BREAKING UP WITH ONSET OF DAYTIME
HEATING. LATEST 06Z WRF DELAYS THE ARRIVAL OF THE COLD FRONT AND
ASSOCIATED PRECIP LATER THIS AFTERNOON. BEFORE MAKING ANY
WHOLESALE CHANGES...WILL ALLOW DAYSHIFT TO EVALUATE NEW 12Z
GUIDANCE ONCE IT COMES IN. NO OTHER CHANGES NEEDED AT THIS TIME.
.PREVIOUS NEAR TERM DISCUSSION...
EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING AN EXPANDING AREA
OF LOW STRATUS WORKING NORTH INTO CENTRAL NEW YORK EARLY THIS
MORNING. THIS IS OCCURRING AS SOUTHERLY L0W-LEVEL FLOW INCREASES
AHEAD OF THE NOW OPEN WAVE TROUGH ACROSS THE CENTRAL MID-ATLANTIC
REGION. SO FAR REGIONAL RADARS ARE ONLY SHOWING A FEW WEAK RETURNS
DOWN ACROSS SOUTH- CENTRAL PA AS MAIN FORCING REMAINS WELL SOUTH
OF OUR REGION. WITH CLOUDS EXPANDING NORTH IN A WARM AIR ADVECTION
REGIME...EARLY MORNING TEMPS HAVE BEEN VERY SLOW TO FALL WITH
SEVERAL SITES STILL SHOWING VALUES IN THE LOWER 70S AS OF 07Z.
BASED ON NON-IMPRESSIVE RADAR TRENDS...WILL START THE FCST DRY
ACROSS ALL LOCATIONS BEFORE AFOREMENTIONED OPEN WAVE FEATURE
BEGINS WORKING NORTHEAST LATER THIS MORNING. AS THIS OCCURS...A
FEW DEVELOPING SHOWERS FROM THE LOWER WYOMING VLY NORTHEAST
THROUGH THE CATSKILLS AND POCONOS WILL BE POSSIBLE HOWEVER POOR
INSTABILITY WILL KEEP THIS INITIAL ACTIVITY OF THE SHOWER VARIETY.
ACTIVITY ACROSS THE EASTERN ZONES WILL TAKE A SIDE SEAT LATER THIS
AFTERNOON AS A WELL ADVERTISED COLD FRONT BEGINS WORKING THROUGH
THE REGION BETWEEN 18-21Z. UPSTREAM RADAR TRENDS TO THE WEST NOW
SHOWING A FAIRLY WELL DEVELOPED AREA OF SHWRS WORKING EAST THROUGH
EASTERN MI AND WESTERN PORTIONS OF THE SOUTHERN ONTARIO PENINSULA
EARLY THIS MORNING. QUICK LOOK AT VARIOUS BUFKIT FCST SOUNDINGS
SUGGEST INCREASING INSTABILITY GENERATION PRIOR TO FROPA LATER
TODAY WITH MLCAPE VALUES ARE FORECAST TO REACH 500-700 J/KG. THIS
WILL LIKELY BE ENOUGH TO GET SOME CONVECTION GOING AS THE FRONT
MOVES THROUGH AND WILL ADVERTISE AN ISOLATED TO SCATTERED THUNDER
MENTION LATER TODAY INTO TONIGHT. IN TERMS OF SEVERE WX
POTENTIAL...WIND FIELDS ALOFT ACTUALLY LOOK A LITTLE WEAKER THAN
IN PREVIOUS DAYS WITH 0-6KM BULK SHEAR VALUES FORECAST TO REACH 30
KTS AS UPPER JET CORE MOVES OVER THE AREA. THAT SAID...MAIN
LIMITING FACTOR PREVENTING SEVERE WX LATER TODAY AND TONIGHT WILL
BE THE MEAGER INSTABILITY GENERATION AS HIGHLIGHTED ABOVE.
RAIN WILL COME TO AN END FROM WEST TO EAST AFTER 06Z. TOTAL
RAINFALL TOTALS WILL LIKELY RANGE ANYWHERE FROM A QUARTER TO HALF
INCH...HOWEVER HIGHER AMOUNTS WILL BE POSSIBLE UNDER CONVECTIVE
CELLS. ANOTHER TRICKY ASPECT OF THE FCST REVOLVES AROUND HIGH
TEMPS TODAY AS ALL MODELS SHOW A FAIRLY IMPRESSIVE 925 MB THERMAL
RIDGE MOVING OVER THE AREA AHEAD OF THE FRONT. THAT COMBINED WITH
WINDS VEERING TO THE SOUTHWEST AHEAD OF THE BOUNDARY WILL LIKELY
ALLOW TEMPS TO WARM WELL INTO THE LOWER TO MIDDLE 80S ACROSS MUCH
OF CNY...WITH UPPER 70S TO LOWER 80S LIKELY FURTHER SOUTH WHERE
GREATER AMOUNTS OF CLOUD COVER ARE EXPECTED.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
ON TUESDAY...FCST MODELS CONTINUE TO SHOW A SECONDARY COLD FRONT
MOVING THROUGH THE AREA WHICH WILL ALLOW EVEN COOLER AIR TO FILTER
INTO THE EASTERN GREAT LAKES. WITH LIMITED LOW-LEVEL MOISTURE TO
WORK WITH...THE GENERAL CONSENSUS IS THE FRONTAL PASSAGE WILL BE
DRY. COLD AIR ADVECTION IN DEVELOPING NORTHWEST FLOW ALOFT ON
TUESDAY WILL SUPPORT LAKE CLOUD GENERATION ACROSS MUCH OF THE LAKE
PLAIN INTO THE NORTHERN FINGER LAKES AS 850 MB TEMPS DROP TO NEAR
12C. HIGH TEMPS WILL LIKELY ONLY REACH INTO THE LOWER TO MIDDLE
70S.
HIGH PRESSURE WILL THEN SETTLE INTO THE REGION TUE NIGHT BEHIND
THE SECONDARY FRONT. THE ARRIVAL OF THIS FEATURE WILL RESULT IN
FAIR AND COOLER CONDITIONS THROUGH THE CONCLUSION OF THE PERIOD.
OVERNIGHT LOWS EARLY WED MORNING MAY DROP INTO THE UPPER 40S
ACROSS FAVORED VALLEY LOCATIONS WITH HIGH TEMPS ON WED ONLY
WARMING INTO THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
330 AM UPDATE...CURRENT EXTENDED FORECAST IN GOOD SHAPE WITH ONLY
MINOR ADJUSTMENTS MADE. MODELS CONTINUE TO SHOW A DRY/WARM STRETCH
OF WEATHER THURSDAY THROUGH SATURDAY, WITH A LARGE UPPER LEVEL
RIDGE ACROSS THE NORTHEAST AND SFC HIGH PRES ALONG THE EAST COAST.
MODEL CONSENSUS AND NHC TRACK FOR ISAAC INDICATES LANDFALL ALONG
THE SOUTHERN LA COAST TUESDAY EVENING. REMNANT MOISTURE FROM THIS
SYSTEM MAY AFFECT AREA SATURDAY NIGHT INTO SUNDAY, BUT THIS FAR
OUT MUCH CAN CHANGE.
PREVIOUS DISC...
EARLY PART OF THE EXTENDED PERIOD FEATURES RISING HEIGHTS AS A
LARGE UPPER LEVEL RIDGE BUILDS IN THE CENTER OF THE U.S. THROUGH
THE OHIO VALLEY...WHICH SHIFTS EASTWARD INTO THE MID-ATLANTIC AND
NORTHEAST STATES BY THE END OF THE WEEK. THIS WILL SPELL A PERIOD
OF DRY WEATHER WITH ABOVE NORMAL TEMPERATURES FOR THIS TIME OF
YEAR...WITH HIGHS NEAR 90 IN LAKE PLAIN AND TYPICAL WARMER SPOTS
FOR FRIDAY AND SATURDAY.
MODEL GUIDANCE CONTINUES A SOMEWHAT SLOWER AND MORE WESTWARD TREND
WITH ISAAC...WITH THE OFFICIAL TRACK FROM NHC NOW MAKING LANDFALL
ALONG THE MS COAST WEDNESDAY MORNING. THIS WILL LIKELY CONTINUE TO
CHANGE WITH UPCOMING MODEL RUNS. THE RESULT FOR US IS MAINLY THAT
ANY MOISTURE TO GET WRAPPED AROUND THE PERIPHERY OF HIGH PRESSURE
SETTLING OFF THE EAST COAST WOULD BE A BIT SLOWER IN ARRIVING...MORE
TWD LATER IN THE WEEKEND.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
STRATUS DECK IS CURRENTLY SPREADING ACROSS THE SOUTHERN TERMINALS
AND THIS WILL PERSIST UNTIL MID MORNING. AT KAVP/KBGM/KELM, LOW
MVFR CIGS WILL OCCUR UNTIL MID MORNING WITH OCCASIONAL IFR CIGS
THROUGH 12Z. AT KITH, MVFR CIGS WILL DEVELOP AFTER 09Z. FOR
KRME/KSYR, CIGS AROUND 4K FT WILL DEVELOP TOWARD DAYBREAK. BY
MIDDAY, CU FIELD WILL SCATTERED OUT WITH MAINLY MID LEVEL CLOUDS.
COLD FRONT WILL CROSS AREA OVERNIGHT BRINGING MVFR SHOWERS. THIS
ACTIVITY WILL BEGIN AROUND 22Z OVER WESTERN TAF LOCATIONS AND
AROUND 02Z AT KAVP.
LIGHT AND VARIABLE WINDS EARLY THIS MORNING BECOMING S/SW BY MID
MORNING AROUND 10 KNOTS THEN SOUTHWEST THIS EVENING.
OUTLOOK...
TUE THRU FRIDAY...MAINLY VFR...LATE NGT VLY FOG PSBL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG
LONG TERM...JML/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
933 AM EDT MON AUG 27 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER JUST OFF THE COAST THROUGH
TONIGHT. A COLD FRONT WILL MOVE IN FROM THE NORTHWEST TUESDAY AND
BECOME STATIONARY OVER THE AREA THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 930 AM MONDAY...SHOWERS AND A FEW TSTMS HAVE FORMED IN AXIS
OF DEEP MOISTURE AND MODERATE INSTABILITY ALONG THE COAST
ASSOCIATED WITH AN INVERTED SURFACE TROUGH AND SOME WEAK SPOKES OF
MID-LEVEL ENERGY ROTATING AROUND THE LARGER CIRCULATION OF
TROPICAL STORM ISSAC IN THE GULF OF MEXICO. LATEST RAP MODEL SHOWS
THIS ACTIVITY PERSISTING THROUGH AFTERNOON WHILE GRADUALLY
SHIFTING INLAND THIS AFTERNOON WHERE BETTER HEATING WILL OCCUR
THIS MORNING WITH THE SEA BREEZE PROVIDING A TRIGGERING MECHANISM.
NO MAJOR CHANGES TO MAX TEMPERATURE FORECAST AS MOST AREAS SHOULD
REACH THE MIDDLE 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 400 AM MON...APPROACHING SHRT WV FROM NW AND ASSCTD SFC FRONT
WILL LEAD TO MORE OF AN INLAND TROF PATTERN TONIGHT WITH SFC WINDS
BECOMING S-SW...WITH SCT SHOWER/ISOLD TSTM THREAT MAINLY ALONG SRN
COASTAL SECTIONS. CANNOT RULE OUT ISOLATED THREAT INLAND WITH
CONTINUED MOIST/UNSTABLE CONDITIONS...THUS WILL CONTINUE WITH
PREVIOUS FCST OF SLGT CHC POPS OVER INLAND SECTIONS AS WELL. RAISED
TEMPS A FEW DEGS IN LINE WITH MOS BLEND...LOW TO MID 70S.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 345 AM MON...MODELS CONVERGING ON A LANDFALL OF ISAAC TO THE
WEST OF THE FL PANHANDLE...AND THIS WOULD HAVE AN INFLUENCE ON
RAINFALL TOTALS ACROSS E NC. DESPITE THE FURTHER WEST
LANDFALL...THERE WILL BE SOME INDIRECT INFLUENCES OF ISAAC ACROSS
THE AREA...NAMELY A PERIOD OF HEAVY RAIN...THOUGH NOT EXPECTING THE
3 TO 5 INCHES AS PREVIOUSLY THOUGHT. HAVE FOLLOWED THE ECM SOLN WITH
REGARD TO TIMING AND LOCATION OF SYNOPTIC FEATURES AND RAINFALL.
A TROUGH OF LOW PRESSURE AND COLD FRONT PROGGED TO MOVE INTO THE
AREA TUE INTO WED...AND AS ISAAC APPROACHES GULF COAST...SOME OF THE
MOISTURE FROM THE STORM WILL BE ABSORBED BY THE TROUGH...AND PROVIDE
E NC WITH INC RAIN CHANCES. INC POPS TUE TO LIKELY ACROSS THE
SOUTHERN TIER...WITH HIGH CHANCE SCT PRECIP FURTHER NORTH. TIMING OF
SHORTWAVE ENERGY WILL BE TUE 18Z...WITH SCT TO NUMEROUS
SHOWERS/THUNDERSTORMS DEVELOPING BY MORNING. THE GFS IS A BIT DRIER
ON TUE WITH A MORE FLAT/PROGRESSIVE TROUGH TO THE NORTH...AND WOULD
LIMIT AMOUNT OF RAIN.
FOR TUE NIGHT...HEAVY RAIN MAY AFFLICT THE REGION...AS AREA WILL BE
UNDER RIGHT EXIT REGION OF JET STREAK WHICH WOULD PROVIDE GOOD
DIVERGENCE ALOFT...AND WITH MOISTURE STREAMING NORTHEASTWARD FROM
ISAAC...FAVORABLE FOR A PERIOD OF HEAVY RAIN AND THUNDERSTORMS. HAVE
INC POPS TO LIKELY...AGAIN WITH THE BEST CHANCES ACROSS SOUTHERN
PORTIONS OF THE CWA. RAIN AND STORMS WILL LINGER INTO WED BEFORE
HIGH PRES BEGINS TO RIDGE IN AT THE SFC. ATTM A GENERAL 1 TO 2
INCHES OF RAIN IS NOT OUT OF THE QUESTION...WITH SOME HIGHER AMOUNTS
WHERE HEAVIER STORMS DEVELOP. NOT EXPECTING ANY SEVERE THUNDERSTORMS
AS LARGE INSTABILITY VALUES AND SIGNIFICANT SHEAR WILL BE LACKING...
AND MAIN THREAT WILL BE LOCALIZED FLOODING. SHOULD GFS SOLN PAN
OUT...RAIN TOTALS WILL BE LESS THAN CURRENTLY FCST.
BOTH MODELS IN AGREEMENT ON HIGH PRES BOTH SFC AND ALOFT BUILDING
INTO THE AREA MID TO LATE WEEK...AND PRECIP CHANCES WILL DIMINISH
AFTER WED. TEMPS TUE AND WED WILL BE HELD DOWN WITH HIGHS AROUND 80
DUE TO RAIN AND CLOUDS...BEFORE CLIMBING BACK INTO THE MID TO UPPER
80S LATE WEEK.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH 12Z TUESDAY/
AS OF 655 AM MON...LIGHT ONSHORE LOW LVL FLOW AND MOIST LOW LVLS HAS
RESULTED IN IFR STRATUS/FOG ALL BUT KEWN PAST FEW HOURS...AND
EXPECTED TO CONTINUE NEXT 1-2 HRS. SCT SHOWERS/ISOLD TSTMS ALONG SRN
COASTAL SECTIONS WILL SPREAD/DEVELOP INLAND DURING MORNING...WITH
CONTINUED CONVECTIVE THREAT THROUGH AFTN...AND WILL CARRY FEW HOURS
OF VCTS ALL SITES. ISOLATED ACTIVITY CANNOT BE RULED OUT DURING
EVENING AND OVERNIGHT BUT PROBABILITIES TOO LOW FOR FCST MENTION.
PTCHY IFR FOG/STRATUS LIKELY AGAIN OVERNIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...SCT TO NUMEROUS SHOWERS AND STORMS EXPECTED TUE
AND WED...AND WILL SEE CONDITIONS DROP TO MVFR AND POTENTIALLY IFR
IN THE RAIN AND CLOUDS. CONDITIONS IMPROVE BY WED NIGHT AND ESP
THUR AS HIGH PRES BUILDS IN.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/
AS OF 935 AM MONDAY...A GENERALLY LIGHT SE/S WIND SHOULD BECOME
MORE SOUTHWEST THIS AFTERNOON AS INVERTED SURFACE TROUGH FEATURE
WEAKENS AND MOVES INLAND. NO MAJOR CHANGES NEEDED TO CURRENT
FORECAST AS WW3 AND SWAN AGREE ON LONGER PERIOD SE SWELL KEEPING
SEAS MAINLY 4-5 FT DURING PERIOD.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...SW FLOW WILL BE AROUND 10 TO 15 KT TUE...SWITCHING
TO E AND NE ON WED 5 TO 10 KT AS A TROUGH AND COOL FRONT DIP DOWN
INTO THE AREA. SCT TO NUMEROUS SHOWERS/STORMS EXPECTED ON TUE AND
WED AS MOISTURE FROM ISAAC IN COMBINATION WITH THE TROUGH AND COLD
FRONT PRODUCE UNSETTLED WEATHER. E AND NE WINDS WILL SWITCH TO SOUTH
ON FRI AND SAT AS HIGH PRES MOVES EAST OF THE AREA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ095-
103-104.
MARINE...NONE.
&&
$$
SYNOPSIS...HSA
NEAR TERM...CTC
SHORT TERM...HSA
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/CTC/TL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
656 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE OHIO VALLEY THROUGH THIS
EVENING...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
REGION. HIGH PRESSURE WILL THEN BUILD IN ACROSS THE GREAT LAKES
THROUGH THE REST OF THE WORK WEEK...RESULTING IN DRY CONDITIONS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WIDESPREAD SHOWER ACTIVITY ALONG WITH SOME EMBEDDED THUNDERSTORMS
IS PUSHING SLOWLY EAST ACROSS NORTHERN INDIANA OVER INTO NORTHWEST
OHIO THIS MORNING. SHOWER ACTIVITY TO THE SOUTHWEST OF THIS IS MORE
SCATTERED...STRETCHING DOWN INTO SOUTHERN ILLINOIS. THE PCPN IS
ASSOCIATED WITH A MID LEVEL SHORT WAVE ALONG WITH A WEAK COLD
FRONT THAT IS FORECAST TO PUSH EAST ACROSS OUR AREA THIS
AFTERNOON. STILL EXPECT THE HIGHEST POPS TO BE ACROSS OUR
NORTH...CLOSER TO THE TRACK OF THE SHORT WAVE. HOWEVER...THE LAST
FEW RUNS OF THE HRRR ARE TRYING TO DEVELOP SOME BETTER PCPN ACROSS
CENTRAL PORTIONS OF OUR FA...AND THIS SEEMS TO BE GETTING SOME
SUPPORT BY THE LATEST RAP AND EVEN THE 00Z NAM. INTERESTINGLY...THE
NAM IS MAINTAINING A COMPACT 20-30 KNOT 850 KNOT JET AS IT PIVOTS
ACROSS THE AREA THROUGH THIS AFTERNOON. TEMPERATURE FORECAST AND
INSTABILITY ARE SOMEWHAT PROBLEMATIC DEPENDING ON HOW FAST CLOUDS/PCPN
OVERSPREAD THE AREA THROUGH THE REMAINDER OF THE MORNING/EARLY AFTERNOON.
THIS COULD KEEP PCPN MORE SHOWERY WITH SOME EMBEDDED ISOLATED TO
SCATTERED THUNDERSTORMS. EXPECT WARMEST TEMPERATURES TO BE ACROSS
OUR SOUTHEAST WHERE CLOUDS/PCPN SHOULD ARRIVE LAST. WILL RANGE
HIGHS FROM THE LOWER 80S NORTHWEST TO MID AND UPPER 80S ACROSS THE
SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
PCPN SHOULD GENERALLY TAPER OFF THROUGH THE OVERNIGHT HOURS AS
SHORT WAVE PUSHES OFF TO THE EAST. HOWEVER...IT WILL BE TOUGH TO
RULE OUT SOME LINGERING SHOWERS ACROSS THE SOUTH AS THE FRONT
LINGERS ALONG THE OHIO RIVER. HIGH PRESSURE WILL THEN BUILD DOWN
ACROSS THE GREAT LAKES TUESDAY INTO WEDNESDAY. HIGHS BOTH DAYS
WILL BE IN THE LOW TO MID 80S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LARGE SFC HIGH PRESSURE STRETCHING FROM THE EASTERN GREAT LAKES BACK
INTO THE PLAINS WILL DOMINATE THE REGIONS WEATHER AT THE BEGINNING
OF THE PERIOD. THE HIGH BEGINS TO TRANSITION EASTWARD ON THURSDAY
ALLOWING ROOM FOR ISAAC TO MAKE LANDFALL.
THE OFFICIAL TRACK OF ISAAC HAS TRENDED W TODAY...FOLLOWING A GOOD
NUMBER OF THE OPERATIONS MODELS TRENDS. THE 12Z GFS IS THE FARTHEST
W WITH THE LANDFALL...PUSHING IT INLAND AROUND PORT ARTHUR TX. THE
CANADIAN AND NOGAPS ARE CLOSE TO THE NHC TRACK WITH LANDFALL IN
MS...WHILE THE 12Z ECMWF BRINGS IT ONSHORE IN ALABAMA.
THERE IS A WIDE SPREAD IN PATH AFTER LANDFALL. THE GFS TAKES THE LOW
INTO PLAINS BEFORE RECURVING UP THE OHIO VALLEY. THE OTHER MODELS
TAKE THE CIRCULATION UP THROUGH THE MS VALLEY OR WRN TN/KY AT
VARYING SPEEDS. CONFIDENCE IS LOW WITH THE WEEKEND FORECAST. THE
TREND OF THE MODELS WITH ISAAC HAS BEEN WESTWARD...SO IT COULD MAKE
LANDFALL IN LOUISIANA OR ERN TX. IF IT GOES THIS FAR W...THE ONSET
OF THE PCPN COULD BE DELAYED OR IT COULD DRY UP.
FOR NOW...FOLLOWED THE HPC SOLUTION WHICH BRINGS THE SFC LOW TO WRN
KY BY SATURDAY MORNING AND LOW CHC PCPN UP INTO THE REGION FRIDAY.
CHANCE OF PCPN SHOULD INCREASE OVER THE WEEKEND...BUT KEPT POPS IN
THE CHC CATEGORY FOR NOW.
AS THE HIGH SLIDES EAST BY THURSDAY...TEMPERATURES WILL BEGIN TO
WARM....WITH HIGHS IN THE MID 80S TO LOWER 90S. THEY COULD GET A
LITTLE WARMER WITH THE SUBSIDENCE AHEAD OF THE HURRICANE...SO WILL
HAVE TO KEEP AN EYE ON THE THIS IN LATER FORECASTS. WITH CLOUDS
AND PCPN WORKING IN FOR THE END OF THE FA PERIOD...LOWERED
TEMPERATURES BACK INTO THE LOWER TO MID 80S FOR SATURDAY AND
SUNDAY...BUT THEY COULD BE COOLER THE PCPN HOLDS TOGETHER MORE.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
CLOUDS WILL CONTINUE TO SPREAD ACROSS THE AREA THIS MORNING
AHEAD OF AN APPROACHING COLD FRONT. CONVECTION ACROSS INDIANA
WILL GRADUALLY WEAKEN AS IT MOVES INTO OUR AREA THIS
MORNING...HOWEVER SOME OF THIS ACTIVITY SHOULD HOLD TOGETHER TO
PRODUCE LIGHT RAIN AND A FEW RUMBLES OF THUNDER...MAINLY ACROSS
THE WESTERN TERMINALS. THE FRONTAL BOUNDARY WILL PROGRESS EASTWARD
ACROSS THE AREA DURING THE DAY. ADDITIONAL THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE JUST AHEAD THIS FRONT DURING THE
AFTERNOON. WINDS WILL GRADUALLY SHIFT FROM SOUTHWEST TO NORTHWEST
AS THE FRONT PASSES LATER TODAY.
SOME UNCERTAINTY REMAINS REGARDING THE EVOLUTION OF LOW CIGS
CURRENTLY ACROSS ILLINOIS AND INDIANA. THIS DECK SHOULD LIFT AFTER
SUNRISE ALLOWING FOR CIGS TO REMAIN VFR IN OUR AREA AS THE FRONT
MOVES THROUGH. HOWEVER...THERE IS THE POSSIBILITY OF MVFR CIGS
DEVELOPING TONIGHT BEHIND THE FRONT IN THE NORTHERLY FLOW.
.OUTLOOK...NO SIGNIFICANT WEATHER.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
823 AM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT OVER THE GREAT LAKES THIS MORNING WILL PUSH
THROUGH PENNSYLVANIA TONIGHT AND EARLY TUESDAY. HIGH PRESSURE
WILL BUILD SOUTHEAST ACROSS THE REGION DURING THE SECOND HALF OF
THE WORK WEEK. THE REMNANTS OF ISAAC COULD POTENTIALLY AFFECT
PENNSYLVANIA BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FORECAST AND GRIDS TO REFLECT THE CONVECTION AND RADAR NOW
EAST OF OUR COUNTY WARNING AREA. UPDATED FORECAST TO LOWER POPS IN
EASTERN AREAS. STILL POTENTIAL FOR SCATTERED LINGERING SHOWERS IN
A FEW LOCATIONS. BUT DECREASING FAST.
USED IR/VIS BLEND TO MAKE MORNING CLOUDS TO SHOW PARTLY TO MOSTLY
SUNNY IN FAR WESTERN AREAS AND BLENDED INTO FORECASTS WHICH SHOW
CLOUDS OVER OHIO COMING INTO THE NORTHWESTERN AREAS LATER THIS
MORNING...OVER SOME LOWER CLOUDS IN EXTREME NW PA. THE 4KM NAM
DOES NOT BODE WELL FOR SUNNY SKIES...FORMS NEW LOW CLOUDS IN EAST
AS FRONTAL CLOUDS COME IN FROM WEST THIS AFTERNOON...ALWAYS TOMORROW!
BELIEVE THE 16KM IS FAR TOO WET IN EAST TODAY...THOUGH 4KM
NAM...HRRR AND RUC ALL IMPLY ONE LAST UPPER-LOW EASTERLY FLOW BAND
COULD CLIP SE...PERHAPS YORK AND LANCASTER COUNTIES SO KEPT CHANCE
DOWN THERE.
IN WEST MOST GUIDANCE IMPLIES SHOWERS ARRIVING MID-TO-LATE
AFTERNOON IN NW. CAPE IS QUITE MEAGER BUT STILL AUGUST AND SHOWER
WITH THUNDERSTORMS POSSIBLE. BULK OF SHOWERS COULD BE PRETTY LATE
IN EAST AND SOUTHEAST...NEXT PERIOD.
NOT EXPECTING MUCH SEVERE POTENTIAL DUE TO MEAGER CAPE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MINOR EDITS...SREF AND 06Z 4KM NAM ALL HOW WEAK LINE SHOWERS OVER
CENTRAL PA AT START OF THIS PERIOD. NOT A LOT OF CAPE. MODELS ALSO
SHOW BEST SIMULATED ECHOES OVER CENTRAL AND NORTHERN AREAS.
BOUNDARY GOES SOMEWHAT EAST-WEST. THIS LIMITS QPF IN SOUTHERN
TIER COUNTIES AND SOUTHEAST. THOUGH MODELS SHOW POTENTIAL IN
CENTRAL AREAS OF 0.5 TO 1.0 INCHES OF RAIN.
INDICATIONS ARE CLOUDS AND SHOWER POTENTIAL WILL CONTINUE TO LOWER
TUESDAY. SHOULD BE A PRETTY GOOD AFTERNOON FOR A JOB OR BIKE RIDE
CWA WIDE. NOT SURE WHY THE NEW 16KM SREF LINGERS LOW POPS SO MUCH.
THOUGH AFTER 18Z POPS IN SEE ARE 10-20 PERCENT. EXPECT 09Z SREF TO
LOWER THESE NUMBERS.
PREVIOUS DISCUSSION: COLD FRONT WILL PUSH SE ACROSS THE REGION
TONIGHT...ACCOMPANIED BY SHRA AND A POSS RUMBLE OF THUNDER.
ENSEMBLE DATA SUPPORTS HIGHEST /CATEGORICAL/ POPS ACROSS NORTHERN
PA AND LIKELY POPS ELSEWHERE. ENSEMBLE MEAN QPF RANGES FROM AROUND A
HALF INCH OVR THE NORTH AND LESS THAN A QUARTER INCH SOUTH.
HOWEVER...MUCH HIGHER LOCAL AMTS WILL FALL...GIVEN PWATS CLOSE TO
2 INCHES. ENSEMBLE PROBABILITY CHARTS SUGGEST NORTHERN PA MOST
LIKELY TO SEE LOCALLY HVY AMTS THIS EVENING BTWN 00Z-06Z.
THE COLD FRONT WILL PASS TO OUR SOUTH AND EAST LATE MONDAY NIGHT
OR EARLY TUESDAY...TAKING ANY LINGERING SHRA/TSRA WITH IT. MDLS
TRACK COLD FRONT INTO THE NW MTNS SHORTLY AFTER 06Z...THEN EXITING
THE SE ZONES BY NOON. CLEARING SKIES WILL OVERSPREAD THE REGION
LATE TUE AM...AS MUCH DRIER AIR OVERSPREADS THE STATE. ENS MEAN
850MB TEMPS NR 14C SHOULD SUPPORT HIGHS FROM THE U70S OVR THE
ALLEGHENIES...TO THE M80S OVR THE SUSQ VALLEY. A SECONDARY
SHORTWAVE DIVING ACROSS THE AREA LATE IN THE DAY COULD PRODUCE A
FAIR AMT OF PM CU AND EVEN AN ISOLD LATE DAY -SHRA OVR THE N MTNS.
HOWEVER...WILL LEAVE MENTION OF PRECIP OUT OF FCST FOR NOW AND KEEP
POPS BLW 15PCT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A HIGH CONFIDENCE FCST WED-FRI...AS ALL MED RANGE GUIDANCE BUILDS
SFC HIGH AND LOW PWAT AIR SE ACROSS PA. THUS...ANTICIPATE MCLEAR
SKIES DURING THE SECOND HALF OF THE WEEK. ECMWF MEAN 8H TEMPS
INDICATE HIGHS NR AVERAGE WED...THEN A WARMUP FOR LATE WEEK...AS HIGH
DRIFTS SE OF PA AND RETURN SW FLOW DEVELOPS. DRY AIR WILL LIKELY
RESULT IN A COUPLE OF COOL NIGHTS AT MIDWEEK...WITH WED NIGHT IN
PARTICULAR LOOKING COOL...AS SFC HIGH DRIFTS DIRECTLY OVR THE
STATE. GEFS AND ECMWF ENSEMBLE DATA BOTH PUSH 850MB TEMPS TO ARND
18C BY LATE WEEK...SO HAVE INCREASED HIGHS FRI/SAT TO NR 90F IN
THE VALLEYS.
AN ADDITIONAL CONCERN HEADING INTO NEXT WEEKEND IS THE REMNANTS
OF ISAAC. BULK OF MED RANGE GUIDANCE TAKE WHAT IS LEFT OF ISAAC
AND CURL IT UP AND OVER THE BUILDING UPPER LEVEL RIDGE NEXT
WEEKEND....WHICH COULD TURN OUR WEATHER UNSETTLED. DUE TO INHERENT
MDL UNCERTAINTIES SO FAR OUT...HAVE CONSERVATIVELY INCREASED POPS
TO ARND 40 PCT BY NEXT WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A FEW SHOWERS AND ISOLATED STORMS ACROSS EASTERN SECTIONS FOR
A FEW MORE HOURS.
MAIN ISSUE WILL BE LOW CLDS THAT FORMED LAST EVENING. JST ON
THE WEST SIDE OF THIS NOW. SOME FOG...BUT CLDS LIMITED THE FOG
OVERALL.
EXPECT VFR BY LATE MORNING OR EARLY AFT. STILL A SMALL CHC OF
A SHOWER OR STORM.
COLD FRONT MOVES IN FROM THE GREAT LAKES TONIGHT...EXPECT
CONDITIONS TO BECOME MVFR AND IFR IN SOME SPOTS.
IMPROVING CONDITIONS AFTER THIS...AS HIGH PRESSURE BUILDS
TOWARD THE AREA.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...GRUMM/FITZGERALD
SHORT TERM...GRUMM/FITZGERALD
LONG TERM...FITZGERALD/EVANEGO
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
606 AM CDT MON AUG 27 2012
.SHORT TERM...TODAY THROUGH THURSDAY
359 AM CDT MON AUG 27 2012
AT 4 AM...WIDESPREAD DENSE FOG WAS BEING REPORTED ACROSS CENTRAL
AND SOUTHWEST WISCONSIN...AND PARTS OF NORTHEAST IOWA. THESE SAME
AREAS PICKED UP ANYWHERE FROM 0.75 TO 1.60 INCHES OF RAIN ON
SUNDAY...AND STAYED CLOUDY THROUGHOUT MUCH OF THE DAY. THIS AREA
HAS EXPANDED SOME DURING THE PAST HOUR...SO WILL HAVE TO EXPAND
THE DENSE FOG ADVISORY A BIT FURTHER NORTHWEST. JUST TO THE
NORTHWEST OF THE DENSE FOG AREA...THE PROFILER NETWORK INDICATES A
TROUGH MOVING SOUTHEAST THROUGH NORTHEAST IOWA...AND WESTERN AND
NORTHERN WISCONSIN. DEW POINTS HAVE BEEN FALLING IN THE WAKE OF
THIS TROUGH. THE MAIN QUESTION FOR THIS MORNING IS WHETHER THIS
WILL CAUSE THE DENSE FOG TO DISSIPATE FASTER THAN EXPECTED. IN THE
CASE OF VOLK FIELD AND BLACK RIVER FALLS...THE TEMPERATURES HAVE
BEEN FALLING RIGHT ALONG WITH THE DEW POINTS. WILL JUST HAVE TO
CONTINUE TO MONITOR THIS SITUATION THIS MORNING.
TODAY - THE SOUNDINGS SHOW PLENTY OF DRY AIR ALOFT. AS DIURNAL
MIXING OCCURS...SOME OF THIS DRY AIR WILL WORK ITS WAY TO THE
SURFACE. THE DIURNAL MIX DOWN /MIXING UP TO 825 MB/ TOOL INDICATES
THAT THE DEW POINTS WOULD FALL INTO THE LOWER AND MID 40S. SIMILAR
DEW POINTS WERE SEEN ACROSS THE EASTERN DAKOTAS AND NORTHWEST
MINNESOTA ON SUNDAY AFTERNOON. SINCE THERE IS A POSSIBILITY THAT
THE MIX DOWN DEW POINTS ARE A BIT TOO LOW...WENT WITH A 50-50
BLEND WITH THE NAM MOS DEW POINTS.
TONIGHT - THE MAIN QUESTION IS HOW WIDESPREAD THE VALLEY FOG WILL
END UP BEING. THE BUFKIT SOUNDINGS SHOW THAT THE WINDS WILL BE
5 KNOTS OR LESS UP TO 2.5 KM AND THE SKIES WILL REMAIN CLEAR.
HOWEVER WITH THE DEW POINTS DROPPING INTO 45 TO 52 DEGREE RANGE
THIS AFTERNOON...HOW MUCH OF A RECOVERY WILL THERE BE THIS EVENING
AND OVERNIGHT. THE NAM WHICH HAS A BETTER HANDLE ON THE DEW POINTS
TODAY...STILL SHOWS A 13 DEGREE TEMPERATURE/DEW POINT SPREAD AT
28.03Z...AND A 6 DEGREE SPREAD AT SUNRISE. ALSO WITH THE DRIER DEW
POINTS...THERE IS THE POTENTIAL THAT THE TEMPERATURES COULD END UP
BEING COOLER THAN EXPECTED WHICH COULD PROMOTE THE DEVELOPMENT OF
STEAM FOG OVER THE WARMER RIVERS WHICH COULD AID WITH THE
MOISTENING OF THE LOWEST PORTIONS OF THE BOUNDARY LAYER. AS A
RESULT...WENT WITH JUST AREAS OF VALLEY FOG FROM 27.08Z THROUGH
27.13Z. EVEN IF IT DOES DEVELOP...IT WILL LIKELY BE SHALLOW AND
WOULD BURN OFF QUICKLY ON TUESDAY MORNING.
TUESDAY AFTERNOON INTO TUESDAY NIGHT - THE MODELS INDICATE A
700-500 MB TROUGH MOVE THROUGH SOUTHERN MINNESOTA ON TUESDAY
AFTERNOON AND EVENING...AND NORTHERN AND EASTERN IOWA ON TUESDAY
NIGHT. THIS SYSTEM IS RIDING ON THE EASTERN EDGE OF AN UPPER LEVEL
RIDGE WHICH WILL BE BUILDING QUICKLY EAST INTO THE UPPER
MISSISSIPPI RIVER VALLEY. THE BUFKIT SOUNDINGS SUGGEST THAT THERE
WILL BE SOME MOISTENING BETWEEN 600 AND 500 MB. IN ADDITION...
THERE IS SOME ELEVATED CAPES BETWEEN 500 AND 750 J/KG.
HOWEVER...THERE IS ALSO PLENTY OF DRY AIR BELOW THESE CLOUD
BASES...SO THERE IS SOME QUESTION ON WHETHER THE PRECIPITATION
COULD EVEN MAKE IT TO THE GROUND. SINCE THE MODELS HAVE NOT BEEN
THAT ROBUST WITH THEIR PRECIPITATION CHANCES FOR THIS TIME
PERIOD...KEPT THE FORECAST DRY FOR NOW AND JUST ENHANCED THE CLOUD
COVER SOME.
ON WEDNESDAY AND THURSDAY...IT APPEARS THAT THE NAM/WRF IS MIXING
WAY TOO DEEP /UP TO 700 MB/ AND THE GFS IS NOT MIXING DEEP ENOUGH
/ONLY 925 MB/. WITH THE 850 MB GFS AND ECMWF TEMPERATURE ANOMALIES
RUNNING BETWEEN 2 AND 2.5 STANDARD DEVIATIONS ABOVE NORMAL...THIS
IS RATHER CRUCIAL ON HOW WARM THE AREA WILL ULTIMATELY GET.
DECIDED TO TAKE A COMPROMISE AND MIXED THE AREA UP TO 850 MB. THIS
WOULD RESULT IN HIGH TEMPERATURES IN THE LOWER AND MID 90S. THESE
TEMPERATURES ARE AT OR VERY CLOSE TO THE RECORD HIGHS ON THESE
DATES.
.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
359 AM CDT MON AUG 27 2012
THE MAIN QUESTIONS FOR THIS WEEKEND WILL BE WHERE THE REMNANTS OF
ISAAC WILL END UP AND WHETHER IT WILL INTERACT WITH A TROUGH
MOVING EAST ACROSS SOUTHERN CANADA. MANY OF THE OPERATIONAL MODELS
ARE BRINGING ISAAC NORTH INTO MISSOURI AND CENTRAL/NORTHERN
ILLINOIS. WITH THE MODELS CONTINUE TO SHIFT THE TRACK OF THIS
SYSTEM FURTHER WEST...THE POTENTIAL OF THIS SYSTEM MOVING SOMEWHERE
THROUGH THE MID MISSISSIPPI RIVER VALLEY LOOKS BETTER AND BETTER.
LOOKING AT THE HISTORIC TRACKS OF THE SYSTEMS /25 TOTAL/ THAT
MOVED THROUGH CENTRAL AND NORTHERN ILLINOIS...A MAJORITY OF THEM
EITHER MADE LAND FALL EITHER IN THE MISSISSIPPI RIVER DELTA OR
EASTERN TEXAS. THE LAST TIME THIS OCCURRED WAS THE REMNANTS OF
HURRICANES GUSTAV AND IKE IN 2008. THE NATIONAL HURRICANE CENTER
TRACK IS SOMEWHERE IN THE MISSISSIPPI RIVER DELTA.
A FEW OF THE GFS ENSEMBLE MEMBERS ARE ACTUALLY FASTER WITH THE
CANADIAN SHORT WAVE AND IT HAS THE PRECIPITATION MOVING INTO
NORTHEAST IOWA AND SOUTHERN WISCONSIN ON SATURDAY AFTERNOON.
MEANWHILE THE OPERATIONAL GFS AND ECMWF WOULD SUGGEST THAT THE
PRECIPITATION ASSOCIATED WITH ISAAC WOULD REMAIN TO OUR SOUTH AND
EAST. HOWEVER THESE MODELS DO INDICATE THAT THERE MAY BE SOME
PRECIPITATION ASSOCIATED WITH A COLD FRONT MOVING ACROSS
MINNESOTA. THE GFS ACTUALLY INCREASES ITS PRECIPITABLE WATER UP TO
1.80 INCHES ALONG THIS FRONT. IS THIS AN INDICATION OF A POSSIBLE
PREDECESSOR RAIN EVENT. STUDIES SHOWN THAT THERE IS A VERY HEAVY
RAIN POTENTIAL WELL AHEAD OF RECURVING TROPICAL CYCLONES. SINCE
THERE IS STILL MUCH UNCERTAINTY ON WHERE ISAAC WILL MAKE
LANDFALL...WHERE IT WILL ULTIMATELY TRACK ONCE INLAND...AND THAT
THE MODELS HAVE BEEN KEEPING THE AREA DRY...JUST KEPT THE AREA DRY
THROUGHOUT THIS ENTIRE TIME PERIOD.
&&
.AVIATION...TODAY AND TONIGHT
606 AM CDT MON AUG 27 2012
THE ONLY CONCERN THROUGH THE PERIOD IS WITH FOG AT KLSE. EXPECTING
THE VALLEY FOG TO BEGIN LIFTING AROUND 13Z AND SHOULD COMPLETELY
DISSIPATE BETWEEN 14 AND 15Z. THE CONCERN THEN BECOMES WHETHER THE
FOG WILL REFORM TONIGHT. THE HIGH WILL STILL BE OVER THE AREA FOR
CLEAR SKIES AND WINDS LESS THAN 10 KNOTS UP THROUGH 5K FEET. THE
QUESTION MARK FOR THE FOG IS WHETHER SATURATION WILL OCCUR OR NOT.
THE 27.06Z NAM BUFKIT SOUNDING SUGGESTS DEEP MIXING WILL OCCUR
THIS AFTERNOON WITH TEMP/DEW POINT SPREAD OF 30+ DEGREES POSSIBLE
AND THE RECOVERY THAT OCCURS DURING THE EVENING AND OVERNIGHT WILL
NOT BE ENOUGH TO ALLOW SATURATION TO OCCUR. THE 27.00Z GFS
SOUNDING ALSO SUGGEST SATURATION DOES NOT OCCUR TONIGHT.
HOWEVER...THE 27.09Z RAP SUGGEST THAT THE TEMP/DEW POINT SPREAD
WILL BE ON THE VERGE OF BEING FAVORABLE THIS EVENING WITH A 7
DEGREE TEMP/DEW POINT SPREAD AT 03Z. NOT SURE THIS IS REALISTIC
THOUGH AS THE RAP DOES NOT INDICATE MUCH MIXING DURING THE
AFTERNOON HOLDING THE DEW POINTS UP IN THE 60S.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
348 AM CDT MON AUG 27 2012
WI...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ034-
041>044-053>055-061.
MN...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ096.
IA...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR IAZ010-011-
029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
515 PM EDT MON AUG 27 2012
.SYNOPSIS...
21Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS OUR FORECAST AREA RESIDES
BETWEEN THE UPPER LOW FEATURE OF TROPICAL STORM ISAAC AND AN UPPER
RIDGE OFF THE SOUTHEAST CONUS. WV IMAGERY SHOWS A DEEP SOUTHERLY
FLOW ON THE EASTERN CIRCULATION OF ISAAC MOVING OVER THE FL
PENINSULA. HOWEVER...DESPITE THIS TROPICAL CONNECTION WE HAVE SEEN
SOME FAIRLY SIGNIFICANT DRYING THROUGH THE COLUMN AS A WHOLE WITH A
DROP IN PW FROM THE 12Z SOUNDING FROM 2.6" DOWN TO 1.8". MUCH OF
THIS DRYING HAS OCCURRED ABOVE 500MB AND THE MOIST COLUMN BELOW THIS
LEVEL IS STILL QUITE SUPPORTIVE OF SHALLOW CONVECTION.
AT THE SURFACE...THE PRESSURE GRADIENT HAS REALLY TIGHTENED ACROSS
THE REGION IN THE PAST SEVERAL HOURS. THIS IS PARTLY A RESULT OF THE
DEEPENING OCCURRING WITHIN TROPICAL STORMS ISAAC (CENTRAL PRESSURE
IS DOWN AROUND 981MB). IN ADDITION...SIGNIFICANT CONVECTION ALONG
THE FL EAST COAST TODAY HAS SET UP A COLD POOL AND ASSOCIATED
MESO-HIGH FEATURE TO OUR WEST. CONDITIONS HAVE BECOME RATHER GUSTY
BETWEEN THESE 2 FEATURES AND SHOULD CONTINUE SO FOR AT LEAST SEVERAL
MORE HOURS.
WE DID NOT SEE THE DOMINANT BANDING OF CONVECTION SEEN OVER TOWARD
THE EAST COAST TODAY...BUT THE BREAKS IN THE CLOUD COVER CERTAINLY
RAISED THE INSTABILITY AND RESULTED IN SCT-NMRS SHALLOW
SHOWERS/STORMS THROUGH THE AFTERNOON. REGIONAL RADARS CONTINUE TO
SHOW THE DEVELOPMENT OF THESE CELLS AND WILL KEEP POPS IN THE LIKELY
RANGE THROUGH THE EVENING HOURS.
&&
.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...
TONIGHT...WITH THE LOSS OF DIURNAL HEATING WE SHOULD SLOWLY SEE A
RAMP DOWN IN THE WIND GUSTS...ESPECIALLY OVER THE LAND MASS...AND
ALSO A SLOW DECREASE IN THE COVERAGE OF SHOWERS AND STORMS. THE
MOIST ATMOSPHERE AND SOME GENERAL LOW LEVEL CONVERGENCE WILL KEEP AT
LEAST SOME ACTIVITY ROTATING SOUTH TO NORTH THROUGH THE OVERNIGHT.
HOWEVER...THE BEST CHANCES FOR THESE SHOWERS AFTER THE LATER EVENING
HOURS WILL BE OVER THE COASTAL LAND ZONES AND OVER THE COASTAL
WATERS.
TUESDAY...UPPER RIDGING TRYING TO BUILD IN FROM THE EAST WILL
SLOWLY INCREASE OUR HEIGHTS...HOWEVER THE DEEP SOUTH/SE FLOW WILL
HELP KEEP THE AIRMASS FAIRLY MOIST AND UNSTABLE. THE OVERALL
CONNECTION TO THE CIRCULATION OF ISAAC WILL BE DIMINISHING FOR OUR
AREA...BUT THE AVAILABLE MOISTURE WILL KEEP SHOWERS AND STORMS IN
THE FORECAST...AND RAIN CHANCES IN THE LIKELY RANGE. CERTAINLY
SHOULD NOT BE A WASHOUT OF A DAY BUT A CONTINUATION OF THE FAST
MOVING SOUTH TO NORTH CONVECTIVE CELLS IS EXPECTED. THE COMBINATION
OF THE ELEVATED SOUTHERLY FLOW AND SWELL PROPAGATING BACK TO THE
COAST FROM ISAAC WILL ONCE AGAIN RESULT IN A HIGH RISK OF RIP
CURRENTS ALONG AREA BEACHES FROM PINELLAS COUNTY SOUTHWARD ON
TUESDAY.
WEDNESDAY...ANOTHER DAY OF DEEP SOUTHERLY MOISTURE. GFS/ECMWF BOTH
SHOW A WEAK MID-LEVEL IMPULSE ROUNDING THE BASE OF THE UPPER RIDGE
AND APPROACHING THE NW CARRIBEAN/S FL PENINSULA. SOME WEAK SYNOPTIC
SUPPORT FROM THIS FEATURE ALONG WITH THE ABUNDANT COLUMN MOISTURE
SHOULD KEEP THE COVERAGE OF SHOWERS AND STORMS ABOVE NORMAL.
&&
.LONG TERM (THURSDAY THROUGH SUNDAY)...
ISAAC IS EXPECTED TO JUST HAVE MADE LANDFALL AS THE PERIOD BEGINS
AND THEN MEANDER NORTHWARD OVER THE NATIONS MID-SECTION. HIGH
PRESSURE OVER THE ATLANTIC RIDGES IN ACROSS FL...IN THE WAKE OF
ISAAC...EARLY IN THE PERIOD AND GETS REINFORCED BY HIGH PRESSURE
THAT BUILDS OVER THE MID-ATLANTIC STATES BY WEEKS END AND AND THEN
SHIFTS OUT OVER THE ATLANTIC DURING THE WEEKEND. THE FORECAST CAN
GRADUALLY RETURN TO NORMAL FOR LATE SUMMER WITH SCATTERED SHOWERS
AND THUNDERSTORMS...ALTHOUGH POPS WILL TEND DOWN BY THE WEEKEND.
TEMPERATURES WILL BE ABOUT NORMAL.
&&
.AVIATION
CONTINUED MVFR CEILINGS TODAY WITH SOME BRIEF IFR CEILINGS AND
PERHAPS VISIBILITIES IN RAIN BANDS. GUSTY WINDS TO 30 KNOTS OR MORE
POSSIBLE IN HEAVIER SHOWERS. EXPECT SOME SLOW IMPROVEMENT AFTER 02Z.
&&
.MARINE...
TROPICAL STORM ISAAC CONTINUES MOVING TO THE NORTHWEST TOWARD THE
NORTH-CENTRAL GULF OF MEXICO COASTLINE. ISAAC IS A LARGE STORM AND
HAZARDOUS CONDITIONS WILL CONTINUE OVER THE COASTAL WATERS AS LARGE
WAVES AND SWELLS MOVE ACROSS THE REGION. FOR ADDITIONAL INFORMATION
ON TROPICAL STORM ISAAC...SEE THE LATEST ADVISORIES BEING ISSUED BY
THE NATIONAL HURRICANE CENTER.
&&
.FIRE WEATHER...
DEEP SOUTHERLY FLOW WILL CONTINUE TO BRING ABUNDANT LOW LEVEL
MOISTURE AND ELEVATED RAIN CHANCES TO THE REGION. NO SIGNIFICANT
FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH AT LEAST THE MIDDLE OF
THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 88 78 89 / 60 60 40 60
FMY 78 89 77 90 / 60 60 40 60
GIF 77 90 75 91 / 50 70 30 60
SRQ 80 88 78 89 / 60 60 40 60
BKV 78 90 75 90 / 60 60 40 60
SPG 81 88 80 89 / 60 60 40 60
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
CHARLOTTE-CITRUS-DESOTO-HARDEE-HERNANDO-HIGHLANDS-
HILLSBOROUGH-LEE-LEVY-MANATEE-PASCO-PINELLAS-POLK-
SARASOTA-SUMTER.
COASTAL FLOOD ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
CHARLOTTE-CITRUS-HERNANDO-HILLSBOROUGH-LEE-LEVY-
MANATEE-PASCO-PINELLAS-SARASOTA.
BEACH HAZARDS STATEMENT THROUGH TUESDAY AFTERNOON FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
HIGH SURF ADVISORY UNTIL 4 PM EDT TUESDAY FOR CHARLOTTE-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
GULF WATERS...TROPICAL STORM WARNING FOR BONITA BEACH TO ENGLEWOOD OUT
20 NM-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-ENGLEWOOD TO
TARPON SPRINGS OUT 20 TO 60 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE
RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT TUESDAY FOR TAMPA BAY
WATERS.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...JILLSON
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
221 PM CDT MON AUG 27 2012
.DISCUSSION...
ISSUED 205 PM CDT MON AUG 27 2012
WEAK COOL FRONT HAS FINALLY PUSHED SOUTHEAST OF THE AREA WITH SOME
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS REDEVELOPING ALONG THE
BOUNDARY. FURTHER TO THE NORTH...MUCH DRIER AIR WAS WORKING SOUTH
INTO OUR AREA WITH DEW POINTS LOWERING INTO THE MIDDLE 50S ACROSS
NORTHERN ILLINOIS. EARLY AFTERNOON TEMPERATURES HAVE WARMED INTO
THE MID TO UPPER 80S WITH A SUN-CLOUD MIX.
SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
FOG POTENTIAL TONIGHT ALONG WITH AFTERNOON TEMPERATURES THRU MOST
OF THIS WEEK THE MAIN FORECAST CHALLENGES.
WEAK FRONTAL SYSTEM THAT PUSHED ACROSS OUR AREA LATE LAST NIGHT
THROUGH THIS MORNING WILL CONTINUE TO DRIFT SOUTH OF THE FORECAST
AREA OVERNIGHT...WITH HIGH PRESSURE SETTLING IN FROM THE NW. THIS
FAIR WEATHER SYSTEM CONTINES TO FEED MUCH DRIER AIR SOUTH INTO
THE REGION BUT THE SIGNIFICANT RAINFALL OVER THE PAST 24 HOURS
ACROSS THE NORTH AND FAR SOUTH MAY PRODUCE SOME FOG BY TUESDAY
MORNING. WILL CONTINUE TO HOLD ON TO SOME FOG DEVELOPING LATE
TONIGHT AND INTO EARLY TUESDAY MORNING.
HIGH PRESSURE WILL THEN TAKE HOLD ACROSS THE MIDWEST BRINGING
SUNSHINE AND RATHER WARM TEMPERATURES AGAIN. MODELS CONTINUE TO
INDICATE A WEAK SHORTWAVE CURRENTLY PUSHING ACRS THE NORTHERN
ROCKIES EAST THRU THE PLAINS ON TUESDAY. SOME SCATTERED CONVECTION
WILL ACCOMPANY THE UPPER LEVEL WAVE LATE TUESDAY AND TUESDAY NIGHT
WITH SOME OF THE HI-RES CONVECTIVE ALLOWING MODELS BRINGING A
DECAYING BAND OF SHOWERS AND STORMS TO OUR NORTHWEST LATER TUESDAY
NIGHT. FORECAST SOUNDINGS CONTINUE TO INDICATE SOME VERY DRY AIR
IN PLACE AS THE SURFACE RIDGE REMAINS ANCHORED FROM CENTRAL LOWER
MICHIGAN SW THRU OUR FORECAST AREA TUESDAY NIGHT INTO WED MORNING.
OTHER THAN SOME RESIDUAL MID AND HIGH LEVEL CLOUDS TUESDAY NIGHT
WE ARE NOT EXPECTING ANY PRECIP WITH THIS UPPER WAVE.
THE SURFACE RIDGE AXIS WILL SHIFT SLOWLY TO THE EAST ON THURSDAY
WHICH WILL KEEP OUR AREA VERY WARM AND DRY ONCE AGAIN. THE NAM
850 MB TEMPERATURES BY THURSDAY AFTERNOON WILL BE 20 TO 22 DEG C
WHICH SHOULD HELP PUSH READINGS AT LEAST INTO THE UPPER 80S EAST
TO LOWER 90S WEST. CLOUD COVER WILL BE ON THE INCREASE THURSDAY
NIGHT ACROSS THE SOUTH AS THE REMNANTS OF ISAAC SLOWLY TRACK
NORTH INTO THE LOWER MISSISSIPPI VALLEY.
LONG TERM...FRIDAY THROUGH MONDAY
THE REMNANTS OF ISAAC AND ITS RAIN THREAT INTO THE HOLIDAY WEEKEND
WILL BE THE MAIN FORECAST COCERN THIS PERIOD.
ALTHOUGH MODELS WERE SHOWING BETTER AGREEMENT WITH THE FORECAST TRACK
OF ISAAC...THERE STILL IS QUITE A BIT OF UNCERTAINTY WITH RESPECT
TO THE TRACK AND SPEED OF THE SYSTEM AS IT HEADS NORTH INTO THE
UPPER LEVEL RIDGE OVER THE MIDWEST LATE THIS WEEK. THE NORTHERN
EDGE OF THE PRECIP SHIELD SHOULD GRADUALLY WORK ITS WAY NORTH INTO
SE IL FRIDAY AND CONTINUE TO SPREAD NORTH THROUGH FRIDAY NIGHT.
THE OFFICIAL TRACK ISSUED EARLY THIS AFTERNOON HAS THE SYSTEM JUST
NORTHWEST OF STL BY SATURDAY MORNING WHICH WOULD BRING RAIN TO MOST
OF THE CWA FOR A PORTION OF OUR HOLIDAY WEEKEND.
LATEST ECMWF HAS BROUGHT THE SYSTEM NORTH BUT KEEPS THE DEPRESSION
SOUTH OF STL BY SATURDAY MORNING...A SLOWER SOLUTION...AND THEN
TAKES THE SYSTEM BACK SOUTH THRU KY AND TN BY LATER SUNDAY. CONFIDENCE
ON ANY ONE OF THESE MODELS HANDLING THIS WARM CORE SYSTEM IS LOW AT
BEST SO WILL CONTINUE WITH CHANCE POPS IN THE GRIDS UNTIL WE SEE A
BIT MORE CONSISTENCY...WHICH MAY NOT BE UNTIL LATER THIS WEEK. WHAT
RAIN WE DO SEE STARTING ON FRIDAY SHOULD BEGIN TO PUSH AWAY DURING
THE DAY SUNDAY WITH SOME DRIER AIR SLATED TO MOVE INTO OUR AREA BY
THE END OF THE FORECAST PERIOD.
SMITH
&&
.AVIATION...
ISSUED 623 AM CDT MON AUG 27 2012
MAIN CONCERN AVIATION-WISE IS THE NEXT FEW HOURS. FAIRLY
WIDESPREAD MVFR/IFR CEILINGS OVER THE NORTHERN HALF OF ILLINOIS
INTO ADJACENT PARTS OF MISSOURI AND IOWA. HRRR CEILING GUIDANCE
SHOWING THIS SHOULD RAPIDLY BREAK UP BETWEEN ABOUT 14-17Z...
ALTHOUGH AREAS FROM KPIA-KCMI WHICH HAD HEAVY RAINFALL RECENTLY
MAY TAKE TOWARD THE END OF THAT TIME RANGE. HAVE SEEN SOME BRIEF
VISIBILITY REDUCTIONS BUT FOR THE MOST PART...THE DENSE FOG HAS
REMAINED TO THE NORTHWEST IN AREAS THAT CLEARED OUT FOR A TIME
EARLIER IN THE NIGHT. ONCE THE CLOUDS BREAK UP BY LATE MORNING...
VFR CONDITIONS SHOULD PREVAIL THE REMAINDER OF THE TAF PERIOD. THE
ONLY EXCEPTION WOULD BE SOME PATCHY FOG THAT MAY FORM LATE
TONIGHT AS WINDS BECOME LIGHT...WITH THE PRIMARY CONCERN IN AREAS
THAT HAD HEAVY RAIN. AT THE MOMENT...WILL ONLY MENTION THIS AT KCMI.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
635 PM EDT MON AUG 27 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH TONIGHT AND CROSS THE AREA EARLY
TUESDAY MORNING. HIGH PRESSURE MOVING IN FROM THE WEST WILL BUILD
INTO THE EAST COAST WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...ADJUSTED THE POPS INITIALLY TO REFLECT THE LATEST RADAR
TRENDS AND THEN BLENDED IN THE NAM12 WHICH APPEARS TO BE IN LINE
W/THE RADAR OF WIDELY SCATTERED SHOWERS AND ISOLD TSTMS THIS
EVENING. THE THINKING HERE IS THAT SHOWERS WILL FILL IN LATER
TONIGHT THROUGH EARLY TUESDAY MORNING AS THE FRONT APCHS W/POTENT
UPPER VORT MAX. KEPT DAYCREW`S POPS AFTER 06Z WHICH REFLECTS THIS
WELL ATTM. HEAVY RAFL A GOOD BET AND DAYCREW HAS THIS HANDLED
NICELY AS THE LATEST BUFKIT PROFILES INDICATE HEAVY RAFL POTENTIAL
W/WARM CLOUD PROCESSES.
FOG LOOKS LIKE A POTENTIAL FOR INTERIOR DOWNEAST AND THE COAST AS
LATEST SOUNDINGS INDICATE THIS WELL W/SSW FLOW OFF THE OCEAN.
TWEAKED 18-00Z QPF USING LATEST OBS AND RUC ANALYSIS. QPF WILL
INCREASE AS WELL LATER TONIGHT. NO OTHER CHANGES ATTM.
PREVIOUS DISCUSSION...
AN AREA OF PVA AND UNSTABLE AIR AHEAD OF A STRONG COLD FRONT WILL
PRODUCE SHOWERS AND THUNDERSTORMS TONIGHT. THE SHOWERS WILL SPREAD
SOUTHWARD TOWARDS BANGOR LATER TONIGHT. THERE IS A VOLATILE
MIXTURE OF THE UNUSUALLY WARM AND HUMID AIR MASS AHEAD OF THE
FRONT WITH COOL AND DRY CANADIAN AIR BEHIND THE FRONT. THIS CLASH COULD
ALLOW SHOWERS TOWARDS THE CROWN OF MAINE TO PRODUCE SOME FAIRLY
IMPRESSIVE PRECIPITATION TOTAL..REACHING UP TO AN INCH BEFORE THE
FRONT CROSSES TOMORROW. A DEEP WARM CLOUD LAYER OVER 11000
FEET...A STRONG LLJ AND PW NEARLY 2 INCHES WILL INCREASE THE ODDS
OF LOCALLY HEAVY RAINFALL TONIGHT. THE FRONT WILL SLOWLY DRAG
THROUGH THE STATE TONIGHT AND FINALLY MOVE OFF THE COAST TUESDAY
AFTERNOON. WITH THE PRECIPITATION AND LOW LEVEL MOISTURE PRODUCING
WIDESPREAD LOW CLOUDINESS BY LATER TONIGHT...LOWS WILL ONLY DROP
TO THE LOW TO MID 60S. WITH STRONG COLD AIR ADVECTION BEHIND THE
FRONT...HIGHS TUESDAY WILL ONLY REACH THE UPPER 60S TO LOW 70S
NORTH AND MID 70S DOWN EAST. HUMIDITY WILL DROP MARKEDLY FROM
TODAY`S READINGS IN THE AIR MASS BEHIND THE FRONT THAT WILL
PROVIDE A HINT OF FALL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
COOLER AIR PUSHING INTO THE AREA AHEAD OF HIGH PRESSURE MOVING INTO
THE GREAT LAKES WILL BRING A MOSTLY CLEAR...COOL AND DRY NIGHT
TUESDAY NIGHT. THE HIGH WILL BRING A MOSTLY CLEAR AND COOL MORNING
THROUGHOUT THE REGION WEDNESDAY MORNING. A WEAK WEATHER DISTURBANCE
SLIDING IN FROM THE NORTHWEST ON WEDNESDAY WILL CARRY A BIT OF
MOISTURE WITH IT. THE MOISTURE WILL COME AS A FUNCTION OF SOME
WARM ADVECTION CIRCULATING IN FROM THE WEST JUST NORTH OF THE
HIGH PRESSURE SYSTEM. THIS WILL BRING A MOSTLY CLOUDY MIDDAY AND
AFTERNOON OVER THE NORTH WEDNESDAY WHILE DOWNEAST AREAS REMAIN
SUNNY TO PARTLY CLOUDY. CLOUDS WILL REMAIN ACROSS THE NORTH
THURSDAY NIGHT INTO FRIDAY WHILE DOWNEAST REMAINS PARTLY CLOUDY.
WARM ADVECTION MOISTURE NORTH OF THE HIGH AND JUST SOUTH OF A
SMALL LOW MOVING ACROSS CENTRAL CANADA MAY PROVIDE ENOUGH MOISTURE
TO PRODUCE A FEW SHOWERS OVER THE FAR NORTH THURSDAY AFTERNOON.
TEMPS DURING THE MID WEEK PERIOD WILL BE NEAR...TO JUST A COUPLE
DEGREES BELOW NORMAL FOR LATE AUGUST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
WEAK FRONTAL BOUNDARY DRAPED ACROSS NORTHERN FORECAST AREA WILL
BEGIN TO SLOWLY PUSH NORTH OF ST JOHN VALLEY BY EARLY SATURDAY.
CHANCE OF RAINSHOWERS ACROSS MOST OF AROOSTOOK COUNTY THROUGH
SATURDAY...SLIGHT CHANCE ELSEWHERE. COLD FRONT WILL THEN MOVE IN
FROM QUEBEC THROUGH DAY SATURDAY WITH SHOWERS. COLD FRONT WILL
CLEAR ALL OF FORECAST AREA BY SUNDAY MORNING FOR A SUNNY AND DRY DAY
WITH A HINT OF EARLY FALL IN THE AIR. WEAK SHORT WAVE IN NORTHWEST
UPPER FLOW WILL AGAIN BRING SLIGHT CHANCE OF SHOWERS IN
NORTHWESTERN ZONES MONDAY AFTERNOON. TEMPERATURE WISE LOOK FOR
DAYTIME HIGHS IN LOW TO MID 70S NORTH AND NEAR 80 DOWNEAST ON
FRIDAY THEN MID TO UPPER 60S NORTH WITH MID 70S DOWNEAST SATURDAY
THROUGH MONDAY. LOWS WILL BE MID TO UPPER 50S FRIDAY
MORNING...AROUND 60 SATURDAY...THEN SHARPLY COOLER SUNDAY AND
MONDAY WITH MID 40S NORTH AND LOW 50S ELSEWHERE.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: IFR CONDITIONS ARE EXPECT TO DEVELOP...MOSTLY AFTER
MIDNIGHT WITH THE EXCEPTIONS OF BHB AND FVE. THUNDERSTORMS ARE
POSSIBLE TONIGHT. IFR WILL CONTINUE INTO TUESDAY MORNING FOR ALL
TERMINALS. VFR RETURNS DURING THE AFTERNOON FOR ALL SITES.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY THROUGH WEDNESDAY
ACROSS THE AREA.
&&
.MARINE...
NEAR TERM: FOG IS EXPECTED TO DEVELOP TONIGHT AHEAD OF A COLD
FRONT. ISOLATED THUNDERSTORMS ARE POSSIBLE. SEAS WILL PICK UP
TOWARDS 3 TO 5 FEET IN A SE SWELL TONIGHT AND CONTINUE INTO TOMORROW.
NO SCA IS EXPECTED. MODELS SEEM TO BE ABOUT 1 FOOT HIGH ON
GUIDANCE FOR THIS FRONT.
SHORT TERM: WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/MCW
SHORT TERM...BLOOMER
LONG TERM...PJR
AVIATION...HEWITT/MCW
MARINE...HEWITT/MCW/BLOOMER
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
247 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE AREA TONIGHT AND TUESDAY MORNING
BEFORE PUSHING SOUTH OF THE REGION TUESDAY AFTERNOON. HIGH
PRESSURE WILL PROVIDE DRY CONDITIONS FOR THE SECOND HALF OF THE
WEEK. THE REMNANTS OF ISAAC MAY IMPACT OUR AREA DURING THE
WEEKEND.
&&
.NEAR TERM /TONIGHT AND TUESDAY/...
WK CD FNT CURRENTLY OVR OH WL CROSS THE CWA LATE TNGT/ERLY TUE.
ATTM RW CVRG W/ THIS IS NOT THAT IMPRESSIVE. HRRR SHOWS SCT RW
APRCHG THE NWRN CORNER OF THE FCST AREA LATE THIS EVE. THE SREF IS
ALSO QUITE STINGY W/ RAFL IN THE MID ATLC DUR THE OVRNGT HRS. LOW
CHC POPS/LOW QPF FOR THE OVRNG HRS.
AS THE FNT WL NOT MAKE IT THRU UNTIL LATE THE TEMPS WL RMN WARM.
LOW TEMPS IN THE MU60S W OF I-95...LM70S IN THE CITES AND E OF THE
HWY.
THE FNT IS XPCTD TO MOVE THRU THE CWA DURING THE MRNG HRS. ONLY
SCATTERED SHOWER ACTIVITY WILL MAKE IT PAST THE MTNS...MUCH OF IT
DISSIPATING OVER THE APLCNS. BY MID AFTN...THE FRONT AND ANY
LINGERING PRECIP WILL BE SLIDING DOWN INTO CNTRL/SRN VA AND SOUTH
OF THE CWA. A FEW ISLTD TSTMS WILL BE POSSIBLE TOWARD EARLY AFTN
NEAR THE FRONT...AS TEMPS CLIMB INTO THE 80S - ENOUGH FOR SOME
WEAK INSTABILITY.
A STEADY NWLY BREEZE WILL PICK UP ACROSS NERN MD AND DOWN INTO THE
METRO DC AREA TOWARD THE MID-LATE AFTN...DRYING THE AREA OUT AND
LIMITING THE MAX TEMPS - THOUGH A FEW L90S ARE EXPECTED ALONG-EAST
OF I-95.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
THE COLD FRONT WILL CONTINUE TO PROGRESS SOUTH OF THE CWA TUE
NGT. ALOFT...THE BASE OF AN UPPER TROUGH WILL BE LOCATED OVER THE
MID-ATLANTIC REGION. NW FLOW ALOFT/NLY FLOW AT THE SFC WILL ADVECT
DRIER/COOLER AIR INTO THE REGION. PRESSURE SURGE FROM HIPRES
BUILDING IN FROM THE NORTH WILL LIKELY PRODUCE A 5-10 MPH WIND
OVNGT AND LIMIT RADIATIONAL COOLING. STILL EXPECT MIN TEMPS NEAR
CLIMO.
SFC HIPRES CONTINUES TO BUILD SEWD FROM THE GREAT LAKES REGION WED
AND WED NGT WHILE LARGE-SCALE TROUGHING ALOFT PERSISTS OVER ERN
CANADA AND THE NORTHEAST CONUS. MAINLY CLEAR SKIES AND SEASONABLE
TEMPERATURES WILL PERSIST DURING THIS TIME.
&&
.LONG TERM /THURSDAYTHROUGH MONDAY/...
UPPER SHORTWAVE RIDGE OVER THE CENTRAL CONUS WILL SHIFT EWD LATE
THIS WEEK AS THE REMNANTS OF ISSAC MEANDER OVER THE SRN MS RVR VLY.
BOTH GFS AND ECMWF INDICATE SOME DEGREE OF A REX BLOCK DEVELOPING
TEMPORARILY BETWEEN THESE TWO SYSTEMS THU...BEFORE IT BREAKS DOWN
FRI AND SAT AS THE RIDGE BUILDS EWD TOWARD THE ERN SEABOARD.
DURING THIS TIME...THE REMNANTS OF ISSAC WILL ROTATE AROUND THE
WRN PERIPHERY OF THE RIDGE. THERE IS UNCERTAINTY REGARDING WHEN
AND HOW MUCH MOISTURE FROM ISSAC REACH THE MID-ATLANTIC REGION.
LATEST EXTENDED-RANGE GUIDANCE INDICATES THE RIDGE BREAKING DOWN
THIS WEEKEND...WITH MOISTURE REACHING THE REGION LATE IN THE WEEKEND
AND ERY NEXT WEEK.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A MUCH DIFFERENT AFTN THAN THE PREV TWO DAYS...W/ MOSTLY CLR SKIES
AND ONLY A FEW SCATTERED CUMULUS FIELDS - WHICH WILL DISSIPATE
TOWARD SUNSET. A COLD FRONT IS ON THE WAY HOWEVER...AND WILL MOVE
ACROSS THE REGION AFTER SUNRISE TUE. LOW-END VFR CIGS AND A STEADY
10KT BREEZE WILL ACCOMPANY THE BOUNDARY. BEHIND THE FRONT...WINDS
WILL SHIFT TOWARD WNW FOR THE AFTN HRS AND ONLY A FEW ISOLATED
SHOWERS POSSIBLE DURING THE LATE MRNG HRS.
SFC HIPRES WILL DOMINATE THE MID-ATLANTIC WX PATTERN TUE NGT THRU
THE END OF THE WEEK. VFR CONDITIONS EXPECTED DURING THIS TIME.
&&
.MARINE...
S-SELY WINDS HAVE SLACKENED INTO THE 5-10KT WIDESPREAD...THOUGH A
FEW 10-15KT GUSTS WILL PERSIST INTO THE EVE HRS. SLY CHANNELING
WILL DEVELOPING LATER TONIGHT...BRINGING LOW-END SCA WINDS TO THE
MIDDLE-LOWER MD BAY - ENDING TOWARD THE PREDAWN HRS TUE. A COLD
FRONT WILL SLIDE ACROSS THE WATERS DURING THE LATE MRNG
HRS...SWITCHING THE WIND DIRECTIONS BACK TOWARD THE W-NW FOR THE
AFTN HRS.
THE PRESSURE GRADIENT BETWEEN HIPRES BUILDING IN FROM THE GREAT
LAKES AND LOPRES ALONG A SLOW MOVING COLD FRONT THAT IS PUSHING
SOUTH OF THE WATERS WILL PRODUCE 10-15 KT NLY WINDS TUE NGT. CANNOT
RULE OUT SLIGHTLY HIGHER GUSTS IN AREAS OF THAT ARE PRONE TO NLY
CHANNELING...BUT CONFIDENCE NOT HIGH ENOUGH TO ISSUE A SCA.
LGT WINDS UNDER THE INFLUENCE OF HIPRES THRU THE SECOND HALF OF THE
WEEK.
&&
.TIDES/COASTAL FLOODING...
CANCELLED CF ADZY UNTIL 10 PM...THEN BACK IN EFFECT FOR THE WRN
SHORE OF THE MD BAY AND DC-ALEX/.
GOING INTO THE AFTN HIGH TIDE - WHICH IS THE LOWER OF THE NEXT
TWO...MANY AREAS ARE FALLING SHORT OF MINOR FLOODING THRESHOLDS.
LATER TONIGHT HOWEVER...SLY WINDS WILL STRENGTHEN MORE INTO THE
15-20 MPH RANGE AND HELP TO INCREASE POSITIVE TIDAL ANOMALIES
HEADING INTO THE NEXT H.T. CYCLE. A BETTER CHANCE EXISTS FOR THE
AREAS CURRENTLY IN THE ADZY TO REACH MINOR CF LEVELS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR DCZ001.
MD...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR MDZ007-011-014-017-018.
VA...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR VAZ054.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT
TUESDAY FOR ANZ532>534-537-540>543.
&&
$$
WOODY!/GMS/KLEIN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
156 PM EDT MON AUG 27 2012
.UPDATE...
ISSUED AT 155 PM EDT MON AUG 27 2012
SCATTERED TO BROKEN CU FIELD ACROSS THE UPPER PENINSULA EARLY THIS
AFTERNOON...PRETTY MUCH AS EXPECTED. THICKER AREA OF CU/SC TO THE
NORTHWEST OF LAKE SUPERIOR MAY BE AN ISSUE LATER TONIGHT. CURRENT
FORECAST STILL LOOKS TO BE IN GOOD SHAPE.
UPDATE ISSUED AT 1049 AM EDT MON AUG 27 2012
12Z SURFACE ANALYSIS SHOWS THE UPPER PENINSULA IN THE WAKE OF A COLD
FRONT THAT MOVED ACROSS THE REGION DURING THE OVERNIGHT HOURS...AND
WAS NOW LOCATED FROM NORTHEAST ONTARIO WEST-SOUTHWEST ACROSS THE TIP
OF THE LOWER PENINSULA AND INTO CENTRAL WISCONSIN...WEAKLY CYCLONIC
PRESSURE PATTERN ACROSS THE REGION THIS MORNING. FRONT WAS
SUPPORTED ALOFT BY AN ELONGATED PV ANOMALY...WITH WATER VAPOR
IMAGERY SHOWING A BETTER DEFINED DISTURBANCE HEADING EAST-SOUTHEAST
OVER NORTHWEST ONTARIO. CLOUDS AND SOME SHOWERS ONGOING NORTH AND
NORTHWEST OF LAKE SUPERIOR WITH THIS FEATURE. SKIES ACROSS
WESTERN/CENTRAL UPPER ARE MAINLY CLEAR TO START WITH JUST A PATCH OF
AC EAST OF THE KEWEENAW.
NORTHWEST ONTARIO SHORT WAVE TROUGH FORECAST TO SLIDE INTO WESTERN
UPPER LATER THIS AFTERNOON...BUT THE ENVIRONMENT AHEAD OF THIS
FEATURE IS NOT PARTICULARLY MOIST...AS MUCH OF THE MID/UPPER LEVEL
MOISTURE IS TO THE NORTH OF THE MAIN VORTICITY CENTER. SO OUTSIDE
OF A LITTLE DIURNALLY DRIVEN CU DEVELOPMENT...SHOULD BE A NICE
AFTERNOON. 12Z GRB SOUNDING HAD A NICE MIXED RESIDUAL LAYER BETWEEN
950-780MB...MIXING TO THIS POINT YIELDS AN AFTERNOON HIGH OF 79F
WHICH CURRENT FORECAST SEEMS TO HAVE WELL IN HAND. SO NO BIG
CHANGES IN THE FORECAST AT THIS POINT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT MON AUG 27 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE SRN ROCKIES INTO THE CNTRL PLAINS
RESULTING IN WNW FLOW FROM THE CANADIAN PRAIRIES INTO THE NRN GREAT
LAKES. AT THE SFC...A COLD FRONT THROUGH CNTRL UPPER MI CONTINUED TO
SLIDE TO THE EAST AS HIGH PRES FROM SASK INTO THE NRN PLAINS BUILDS
TOWARD THE AREA. LOW CLOUDS AND FOG AHEAD OF THE FRONT OVER THE ERN
CWA WERE DISSIPATING AS WEAK DRY AIR ADVECTION SCOURS OUT THE LOW
LEVEL MOISTURE. HOWEVER...SOME PATCHY SHALLOW FOG REMAINED OVER
INLAND PORTIONS OF CNTRL UPPER MI. AN ALTHOUGH SKIES WERE MOSTLY
CLEAR OVER MN...NRN WI AND W UPPER MI...AN EXTENSIVE AREA OF
LOW/MID CLOUDS WAS SPREADING THROUGH NW ONTARIO IN THE COOLER AIR WHERE
850 MB TEMPS WERE BLO 8C.
TODAY...AFTER THE LOW CLOUDS MOVE OUT OF THE EAST...EXPECT MOSTLY
SUNNY SKIES ACROSS THE AREA. MIXING SHOULD BOOST TEMPS INTO THE
UPPER 70S TO AROUND 80...GIVEN UPSTREAM MAX READINGS SUNDAY IN
AIRMASS WITH 850 MB TEMPS AROUND 12C. MIXING SHOULD ALSO DROP
DEWPOINTS TO AROUND 50 INLAND.
TONIGHT...AS THE MOISTURE AND COOLER AIR SAGS INTO THE AREA LATE
TONIGHT...SOME INCREASE IN CLOUDS MAY BE POSSIBLE OVER THE NORTH AND
EAST PORTIONS OF THE CWA...PER NAM 925-750 MB RH FCST. HOWEVER...ANY
CLOUDS SHOULD BE TRANSIENT MOVING OUT AROUND DAYBREAK AND HAVE
ONLY LIMITED IMPACT ON MIN TEMPS WHICH SHOULD DROP TO AROUND 50
INLAND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 505 AM EDT MON AUG 27 2012
MAIN FOCUS IN THE EXTENDED IS WARM...MAINLY DRY CONDITIONS. A COUPLE
OF MODELS ARE SHOWING SOME PRECIP THU IN THE WAA AHEAD OF A
TROUGH...AND AGAIN WITH AN UPPER/SFC TROUGH AND COLD FRONT ON
SUNDAY. HOWEVER...WITH EXPECTED LACK OF MOISTURE...AM NOT TOO
EXCITED ABOUT PRECIP CHANCES.
ON TUESDAY...THE CWA WILL BE UNDER NW FLOW ALOFT BETWEEN AN
AMPLIFIED 500MB RIDGE AXIS FROM CO THROUGH SASK INTO THE NW
TERRITORIES AND A 500MB TROUGH FROM NRN QUEBEC DOWN TO ISAAC IN THE
GULF OF MEXICO. A SFC RIDGE WILL BE OVER THE CWA TUESDAY WITH 850MB
TEMPS AT 18Z TUE FROM 8C E TO 12C W. THIS SHOULD LEAD TO SUNNY SKIES
WITH HIGHS IN THE 70S.
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS THE UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AHEAD OF THIS
SYSTEM...850MB TEMPS INCREASE TO AROUND 18C BY 00Z THU AS THE EML
ADVECTS INTO THE AREA. HIGHS WED SHOULD BE IN THE MID 80S TO AROUND
90...EXCEPT IN THE 70S DOWNWIND OF LAKE MICHIGAN. LOW LEVEL MOISTURE
VARIES BETWEEN MODELS...WITH THE 00Z/27 GFS BEING ON THE HIGH SIDE
/1000-700MB RH STILL UNDER 60 PERCENT FOR THE MOST PART/ AND THE
00Z/27 NAM ON THE LOW SIDE /LESS THAN 40 PERCENT 1000-700MB RH/.
WILL GO WITH A MORE MODERATED SOLUTION OF THE ECMWF WHICH WILL LEAD
TO LOW MIN SFC RH. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH
GUSTS TO AROUND 20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE HEIGHT OF THE
EML MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. THE
12Z/26 ECMWF HAS 850MB TEMPS OF AROUND 22C...BUT THE GFS IS WARMER
AT AROUND 26C. EVEN IF THE COOLER ECMWF VERIFIES...HIGH TEMPS IN THE
80S TO LOW 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC LOW
MOVES FROM CENTRAL MANITOBA TO FAR NW ONTARIO...BRINGING A COLD
FRONT TO THE FAR WRN CWA LATE THU EVENING. SW SFC WINDS WILL BE
AROUND 15KTS WITH GUSTS UP TO 20-25KTS. VERY DRY MID/LOW LEVELS WILL
AGAIN LEAD TO LOW MIN SFC RH...SO FIRE WEATHER CONCERNS WILL BE MORE
ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI COULD STILL BE PRETTY WARM
AS MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL
WINDS. AT SHOULD BE A BIT COOLER IN SOME SPOTS AS 850MB TEMPS LOOK
MORE UNIFORM AT AROUND 14C WITH LIGHT LOW LEVEL FLOW. MODELS THEN
SHOW A STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY...WITH
A SFC LOW MOVING OVER OR JUST N OF THE CWA SUN. THIS ALSO BRING A
SFC COLD FRONT INTO THE CWA SUN AFTERNOON/EVENING...WHICH WOULD
PROVIDE A BETTER CHANCE OF RAIN AS LOW LEVEL MOISTURE DOES IMPROVE
SOME. STILL NOT TOO CONFIDENT IN PRECIP CHANCES ON SUN GIVEN THAT
MODELS HAVE BEEN VARYING SOME WITH THIS SYSTEM AND THAT MODELS BRING
REMNANTS OF ISAAC WELL TO OUR S...WHICH MAY ACT TO KEEP THE BETTER
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 155 PM EDT MON AUG 27 2012
MAINLY VFR CONDITIONS EXPECTED THIS AFTERNOON THROUGH TONIGHT...
THOUGH REMNANTS OF SC FIELD ACROSS NORTHWEST ONTARIO AND THE
MINNESOTA ARROWHEAD MAY IMPACT CMX/MQT THROUGH TONIGHT. WINDS
EXPECTED TO BECOME LIGHT TONIGHT AS HIGH PRESSURE BUILDS IN FROM THE
WEST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT MON AUG 27 2012
WINDS SHOULD REMAIN LESS THAN 30KTS THROUGH THE FCST PERIOD. HIGH
PRES OVER S CENTRAL CANADA WILL SLOWLY BUILD OVER THE UPPER GREAT
LAKES THROUGH TUESDAY...BEFORE DIPPING ACROSS THE LOWER GREAT LAKES
TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE OVER SOUTHERN AND CENTRAL
CANADA THURSDAY MORNING WILL SWING ACROSS ONTARIO AND HUDSON BAY
THURSDAY NIGHT...WITH A TROUGH PUSHING ACROSS LAKE SUPERIOR THURSDAY
AFTERNOON INTO FRIDAY. A RIDGE OF HIGH PRESSURE WILL THEN SLIP
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LS...NONE.
LM...NONE.
&&
$$
UPDATE...JPB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JPB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
324 PM EDT MON AUG 27 2012
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA TONIGHT. AS TROPICAL CYCLONE
ISAAC APPROACHES THE NORTHERN GULF COAST ON TUESDAY...THE DEEP
TROPICAL MOISTURE PLUME WILL SPREAD NORTHWARD INTO THE CAROLIN
AS...WHERE IT WILL INTERACT WITH A COLD FRONT APPROACHING FROM THE
NORTHWEST LATE TUESDAY OR TUESDAY NIGHT. THE SLOW MOVING COLD
FRONT COULD POTENTIALLY STALL ACROSS THE AREA ON
WEDNESDAY...BEFORE FINALLY SHIFTING SOUTH OF THE AREA ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM MONDAY...
LATEST SURFACE ANALYSIS SHOWS TROPICAL STORM ISAAC IN THE
EAST-CENTRAL GULF OF MEXICO. A SOUTHEASTERLY LOW LEVEL FLOW OFF THE
ATLANTIC ASSOCIATED WITH ISAAC COMBINED WITH A NARROW RIDGE OF HIGH
PRESSURE EXTENDING SOUTHWESTWARD ACROSS THE WESTERN PIEDMONT OF VA
AND NC HAS RESULTED IN THE DEVELOPMENT OF AN INLAND PENETRATING
COASTAL FRONT. THE FRONT HAS BEEN ENHANCED BY SEA BREEZE BOUNDARIES
ACROSS SOUTHERN COASTAL AREAS AND WITH CONVECTIVE OUTFLOW ACROSS THE
CENTRAL COASTAL AREA. AN AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS IS ASSOCIATED WITH THE BOUNDARY...ELSEWHERE FAIR
WEATHER WITH SCT-BKN CUMULUS IS WIDESPREAD ACROSS THE REMAINDER OF
CENTRAL NORTH CAROLINA.
THE CONVECTION IS EXPECTED TO CONTINUE ADVANCING NORTHWEST THIS
AFTERNOON AND EARLY EVENING. AIDED BY A WEAKLY UNSTABLE AIR MASS
WITH MLCAPE VALUES RANGING FROM 500-1000 J/KG AND ONLY MODEST MID
LEVEL LAPSE RATES. THE CONVECTION IS EXPECTED TO DECREASE IN
COVERAGE AND INTENSITY AS IT MOVES FURTHER INLAND TOWARD THE SFC
RIDGE AND INTO A REGION OF DEW POINTS IN THE MID/UPPER 60S AND
RESULTANT MLCAPE VALUES OF LESS THAN 500 J/KG. THIS TREND IS
SUPPORTED BY RECENT HRRR RUNS WHICH HAS HANDLED THIS WELL. THE
PRECIPITATION MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS THE
SOUTHERN COASTAL PLAIN/SANDHILLS/SOUTHERN PIEDMONT BEFORE FAIR
WEATHER ARRIVES ACROSS CENTRAL LATE THIS EVENING AND OVERNIGHT.
ANOTHER ROUND OF STRATUS AND FOG IS EXPECTED TO DEVELOP LATE
TONIGHT. WITH A SUB-TROPICAL AIR MASS IN PLACE ACROSS THE
REGION...LOWS TONIGHT SHOULD FALL INTO THE 67-72 RANGE FROM WEST TO
EAST. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
AS OF 315 PM MONDAY...
A NORTHERN STREAM SHORT WAVE AND THE ASSOCIATED COLD FRONT WILL BE
MOVING ACROSS THE CENTRAL APPALACHIANS EARLY TUESDAY. THE
SOUTHEASTERLY LOW LEVEL FLOW BECOMES MORE SOUTHWESTERLY AHEAD OF THE
FRONT. AN AREA OF CONVECTION OFF THE FL COAST ASSOCIATED WITH A LOW
LEVEL PERTURBATION WILL ADVANCE NORTH AND NORTHEAST AND MOVE ACROSS
EASTERN AND SOUTHEASTERN SC/NC. RECENT GUIDANCE SUGGESTS THAT THIS
FEATURE WILL LIKELY NOT INTERACT WITH THE FRONT A GREAT DEAL. STILL
THE PERTURBATION IN A REGION OF HIGH PRECIPITABLE WATER THAT WILL BE
ENHANCED BY THE ENTRANCE REGION OF A JET ALOFT WILL PRODUCE AN AREA
OF SHOWERS AND THUNDERSTORMS THAT MOVES ACROSS THE
SOUTHERN/SOUTHEASTERN PORTION OF THE CWA LATE TUESDAY MORNING AND
CONTINUES INTO THE EVENING HOURS. HAVE OPTED TO HOLD OFF ON
INCLUDING LIKELY POPS GIVEN RECENT GUIDANCE FROM CONVECTION ALLOWING
MODELS. AT THIS POINT QPF VALUES ARE EXPECTED TO BE LIMITED AND
GENERALLY RANGE AROUND A HALF INCH WITH A FEW LOCATIONS RECEIVING UP
TO AN INCH. THE SEVERE THREAT AT THIS TIME APPEARS SOMEWHAT LIMITED
WITH MODEST DEEP LAYER SHEAR OF AROUND 20KTS AND A WEAKLY UNSTABLE
AIRMASS WITH MLCAPE VALUES OF 500-1000 J/KG. LOCALIZED HEAVY RAIN IS
THE LARGER THREAT AT THIS TIME.
THE COLD FRONT IS EXPECTED TO SLOWLY DROP SOUTHWARD REACHING THE
SOUTHERN COASTAL PLAIN BY DAYBREAK WEDNESDAY. WITH THE FRONT IN THE
VICINITY AND A DEEP SOUTHERLY FLOW...WIDESPREAD CLOUDINESS SHOULD
DEVELOP AND PERSIST THROUGH THE PERIOD. HIGH TEMPERATURES WILL RANGE
IN THE UPPER 80S ACROSS THE NORTHEAST TO MID 80S ELSEWHERE. LOWS ON
TUESDAY NIGHT WILL RANGE IN THE UPPER 60S TO LOWER 70S. -BLAES
A COLD FRONT WILL BE PUSHING SOUTH THROUGH THE CWA BY 12Z WEDNESDAY
MORNING. THE ASSOCIATED MID LEVEL SHEAR AXIS WILL ALSO PUSH SOUTH
INTO THE AREA...THOUGH MODELS ARE WEAKER WITH THIS FEATURE WITH A
WESTWARD SHIFT IN THE MODEL/NHC TRACK OF TS ISAAC AND LESS
INTERACTION WITH THE SHORTWAVE CROSSING NEW ENGLAND. MODELS SHOW
THE 85OMB TROUGH AXIS DRAPED ACROSS THE AREA JUST NORTH OF THE NC/SC
BORDER WEDNESDAY...WITH PW IN EXCESS OF 2 INCHES JUST TO THE
SOUTH. THE FRONTAL ZONE WILL BE SLOWING AT THAT POINT...SO THE
DELINEATION BETWEEN WIDESPREAD SHOWERS AND DRY CONDITIONS WILL BE
NARROW...ALTHOUGH THE RIGHT ENTRANCE REGION OF A WESTWARD BUILDING
UPPER JET WILL PROVIDE BROAD LIFT TO SUPPORT AT LEAST CHANCE POPS
AREAWIDE. THERE IS THE POTENTIAL HIGHS TO BE WARMER NORTH THAN
SOUTH DEPENDING ON PRECIP COVERAGE AND POTENTIAL BREAKS IN OVERCAST
SKIES...WITH MID 80S POSSIBLE NORTH AND LOWER 80S MORE LIKELY SOUTH.
INSTABILITY SHOULD BE LIMITED BY CLOUD COVER AND WEAK MID LEVEL WIND
FIELDS SHOULD LIMIT AN SEVERE THREAT WEDNESDAY AFTERNOON.
HOWEVER...SHOWERS AND STORMS WILL HAVE HEAVY RAIN WITH A STORM
MOTION SOMEWHAT PARALLEL TO THE FRONT...SO A FLOODING THREAT MAY
EXIST.
THE SURFACE FRONT AND LOW LEVEL TROUGH SHOULD SLIP FURTHER SOUTH
WEDNESDAY NIGHT...AND WITH IT THE FOCUS FOR BETTER PRECIP COVERAGE.
HOWEVER...WE WILL MAINTAIN A CHANCE POPS FOR THE SOUTHERN PIEDMONT
AND SANDHILLS INTO THE OVERNIGHT HOURS AND EARLY
THURSDAY....DECREASING FROM NORTH TO SOUTH ON THURSDAY. LOWS
RANGING FROM THE MID 60S NORTHEAST TO UPPER 60S SOUTHWEST. HIGHS
THURSDAY IN THE MID 80S. -SMITH
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 315 PM MONDAY...
WITH MODELS CONTINUING TO SHIFT SLIGHTLY WESTWARD WITH THE TRACK OF
TS ISAAC...THERE IS STILL QUITE A BIT OF UNCERTAINTY REGARDING THE
EVOLUTION AND TRACK OF ITS REMNANTS...AND HOW THAT WILL PLAY OUT
OVER THE EASTERN US DURING THE UPCOMING WEEKEND INTO EARLY NEXT
WEEK. IN GENERAL...THE REMNANTS OF ISAAC ARE FORECAST TO MOVE
NORTH THROUGH THE CENTRAL PLAINS...AROUND THE MID LEVEL RIDGE AS
THE RIDGE ITSELF BUILDS EAST THE OH VALLEY REGION. MODELS SHOW THE
MID LEVEL RIDGE SHIFTING OVER THE VIRGINIAS/CAROLINAS BY FRIDAY
AND SATURDAY...WITH THE BETTER MOISTURE PLUME SURGING NORTH
BETWEEN THE MS RIVER AND TN VALLEY REGIONS. THIS WOULD GREATLY
REDUCE THE POTENTIAL FOR SHOWERS AND STORMS OVER CENTRAL NC FRIDAY
AND SATURDAY...WITH MOST ACTIVITY FROM THE MOUNTAINS WESTWARD.
CLOUD COVER WILL ALSO BE GREATEST OVER THE WEST....AND HIGHS WILL
ACCORDING VARY FROM SOUTHWEST TO NORTHEAST. UNDER A STRENGTHENING
MID LEVEL RIDGE...MODELS INDICATE 850MB TEMPS APPROACHING 18-19C BY
SATURDAY AND SUNDAY...WHICH BY ITSELF WOULD SUGGEST HIGHS IN THE
MID 90S. THERE IS LIKELY TO BE QUITE A BIT OF CIRRUS EAST OF THE
REMNANTS OF ISAAC...SO HIGHS IN THE UPPER 80S AND LOWER 90S SEEM
MORE REASONABLE AT THIS POINT.
MODELS THEN DIVERGE A BIT BEYOND 00Z SUNDAY REGARDING THE REMNANT
MID LEVEL PV FROM ISAAC...WHICH THE 12Z GFS NOW SHOWING A DEEPER
AN STRONGER MID/UPPER LOW SINKING INTO THE TN VALLEY SUNDAY. THE
12Z ECMWF NOW SHOWS SIGNS OF THE CIRCULATION EVENTUALLY DRIFTING
SOUTHEAST TOWARD THE TN VALLEY AND SOUTHEAST US...WHICH IS
REMARKABLY DIFFERENT THAT ITS PREVIOUS RUN. WE WILL CONTINUE TO
SHOW AN INCREASE IN POPS INTO EARLY NEXT WEEK...ALTHOUGH
CONFIDENCE IS TOO LOW TO INCREASE THE CURRENT SLIGHT CHANCE TO LOW
CHANCE WORDING.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AS OF 210 PM MONDAY...
VFR CONDITIONS ARE PREDOMINATE ACROSS CENTRAL NC THIS AFTERNOON WITH
SCT-BKN CUMULUS WITH BASES OF 3-5KFT. A WESTWARD MOVING COASTAL
FRONT ENHANCED BY SEA BREEZE AND CONVECTIVE BOUNDARIES WILL MOVE
ACROSS THE COASTAL PLAIN THIS AFTERNOON AND COULD BRING A SHORT
PERIOD OF MVFR CIGS/VSBYS IN A RAIN SHOWER. FAIR WEATHER WITH MAINLY
SCT LOW/MID LEVEL CLOUDS IS EXPECTED ELSEWHERE THIS AFTERNOON. FAIR
WEATHER IS EXPECTED EVERYWHERE THIS EVENING AND DURING THE EARLY
OVERNIGHT HOURS BEFORE AREAS OF MORNING STRATUS AND SOME FOG DEVELOP
TOWARD DAYBREAK. HAVE HIGHLIGHTED POTENTIAL FOR A BRIEF PERIOD OF
IFR/LIFR CONDITIONS WITH FOG/STRATUS AT KRWI TUESDAY MORNING WITH
MAINLY MVFR CONDITIONS EXPECTED ELSEWHERE. BKN CLOUDINESS WITH BASES
RANGING FROM 3KFT EAST TO 5KFT WEST ARE EXPECTED ON TUESDAY.
THE WEATHER DURING THE EXTENDED RANGE WILL LARGELY DEPEND ON THE
EVOLUTION OF TROPICAL CYCLONE ISAAC AND A COLD FRONT THAT WILL MOVE
ACROSS THE AREA LATE TUESDAY AND WEDNESDAY. THIS SURFACE BOUNDARY IS
PREDICTED TO STALL OVER THE CAROLINAS. AT THIS TIME... A PERIOD OF
ADVERSE AVIATION CONDITIONS MAY IMPACT THE AREA FROM LATE TUESDAY
THROUGH THURSDAY WITH SUB VFR CEILINGS AS WELL AS SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. MORE WIDELY SCATTERED SHOWERS
WITH A REDUCED POTENTIAL FOR ADVERSE IMPACT IS EXPECTED ON FRIDAY
AND SATURDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES/SMITH
LONG TERM...SMITH
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 PM EDT MON AUG 27 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY...BEFORE WEAKENING
TONIGHT. AS TROPICAL CYCLONE ISAAC APPROACHES THE NORTHERN GULF
COAST ON TUESDAY...THE DEEP TROPICAL MOISTURE PLUME WILL SPREAD
NORTHWARD INTO THE CAROLINAS...WHERE IT WILL INTERACT WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST LATE TUESDAY OR TUESDAY
NIGHT. THE SLOW MOVING COLD FRONT COULD POTENTIALLY STALL ACROSS
THE AREA ON WEDNESDAY...BEFORE FINALLY SHIFTING SOUTH OF THE AREA
ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM EDT...
LATEST SURFACE ANALYSIS SHOWS TROPICAL STORM ISAAC IN THE
EAST-CENTRAL GULF OF MEXICO. A SOUTHEASTERLY LOW LEVEL FLOW OFF THE
ATLANTIC ASSOCIATED WITH ISAAC COMBINED WITH A NARROW RIDGE OF HIGH
PRESSURE EXTENDING SOUTHWESTWARD ACROSS THE WESTERN PIEDMONT OF VA
AND NC HAS RESULTED IN THE DEVELOPMENT OF AN INLAND PENETRATING
COASTAL FRONT. THE FRONT HAS BEEN ENHANCED BY SEA BREEZE BOUNDARIES
ACROSS SOUTHERN COASTAL AREAS AND WITH CONVECTIVE OUTFLOW ACROSS THE
CENTRAL COASTAL AREA. AN AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS IS ASSOCIATED WITH THE BOUNDARY...ELSEWHERE FAIR
WEATHER WITH SCT-BKN CUMULUS IS WIDESPREAD ACROSS THE REMAINDER OF
CENTRAL NORTH CAROLINA.
THE CONVECTION IS EXPECTED TO CONTINUE ADVANCING NORTHWEST THIS
AFTERNOON AND EARLY EVENING. AIDED BY A WEAKLY UNSTABLE AIR MASS
WITH MLCAPE VALUES RANGING FROM 500-1000 J/KG AND ONLY MODEST MID
LEVEL LAPSE RATES. THE CONVECTION IS EXPECTED TO DECREASE IN
COVERAGE AND INTENSITY AS IT MOVES FURTHER INLAND TOWARD THE SFC
RIDGE AND INTO A REGION OF DEW POINTS IN THE MID/UPPER 60S AND
RESULTANT MLCAPE VALUES OF LESS THAN 500 J/KG. THIS TREND IS
SUPPORTED BY RECENT HRRR RUNS WHICH HAS HANDLED THIS WELL. THE
PRECIPITATION MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS THE
SOUTHERN COASTAL PLAIN/SANDHILLS/SOUTHERN PIEDMONT BEFORE FAIR
WEATHER ARRIVES ACROSS CENTRAL LATE THIS EVENING AND OVERNIGHT.
ANOTHER ROUND OF STRATUS AND FOG IS EXPECTED TO DEVELOP LATE
TONIGHT. WITH A SUB-TROPICAL AIR MASS IN PLACE ACROSS THE
REGION...LOWS TONIGHT SHOULD FALL INTO THE 67-72 RANGE FROM WEST TO
EAST. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM MONDAY...
AS AFOREMENTIONED NORTHERN STREAM TROUGH ADVANCES EAST THROUGH THE
NORTHEAST UNITED STATES ON TUESDAY...TRAILING SURFACE COLD FRONT
WILL MOVE SLOWLY EAST SOUTHEAST INTO THE AREA TUESDAY AFTERNOON
AND TUESDAY EVENING... WHERE MODELS SUGGEST IT COULD STALL THROUGH
THURSDAY. WHILE MOISTURE IS CURRENTLY LIMITED WITH THE COLD
FRONT...THE INTERACTION OF THE FRONT WITH THE NORTHERN PERIPHERY
OF THE EXPANSIVE TROPICAL MOISTURE PLUME ASSOCIATED WITH THE LARGE
WIND FIELD OF ISAAC COULD RESULT IN THE POTENTIAL FOR HEAVY RAIN
ACROSS THE CAROLINAS LATE TUESDAY AFTERNOON AND TUESDAY NIGHT...
ESPECIALLY IN THE UPSLOPE AREAS ALONG THE EASTERN SLOPES AND
ACROSS SOUTHERN PORTIONS OF THE STATE WHERE PRECIPITABLE WATERS
ARE EXPECTED TO BE ABOVE TWO INCHES.
IT REMAINS IMPORTANT TO NOTE THAT THIS HEAVY RAIN POTENTIAL WILL
ULTIMATELY DEPEND ON THE TRACK OF ISAAC...WITH ANY WESTWARD DEVIATION
TO THE FORECAST TRACK REDUCING THE HEAVY RAINFALL THREAT. SO AS YOU
CAN SEE...THERE IS STILL LOTS OF UNCERTAINTY AT THIS TIME.. AS SUCH
WILL KEEP POPS IN 40 TO 50 PERCENT CHANCE CATEGORIES. AS FAR AS A
SEVERE THREAT...THERE ARE QUESTIONS ABOUT HOW EXTENSIVE CLOUD COVER
WILL BE DURING THE DAY ON TUESDAY AND HOW IT MAY LIMIT
DESTABILIZATION...BUT SOME OF THE MODELS STILL DEVELOP MODERATE
INSTABILITY ACROSS THE SOUTH/SOUTHEAST. WINDS ALOFT ARE FAIRLY
WEAK...15 TO 20 KNOTS...SO DO NOT EXPECT MUCH MORE THAN AN ISOLATED
SEVERE THREAT TUESDAY AFTERNOON.
HIGHS TUESDAY GENERALLY IN THE LOWER TO MID 80S. OVERNIGHT LOWS
IN THE UPPER 60S ACROSS THE NORTH TO LOWER TO MID 70S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
THERE IS STILL A GREAT DEAL OF UNCERTAINTY FOR THE LONG TERM PERIOD
AS MUCH OF OUR WEATHER WILL ULTIMATELY DEPEND ON THE TRACK OF ISAAC
AND ITS EVENTUAL REMNANTS. THE OFFICIAL NATIONAL HURRICANE CENTER
TRACK HAS ISAAC MAKING LANDFALL SOUTH OF NEW ORLEANS LATE TUESDAY.
HOWEVER...MODELS CONTINUE TO STRUGGLE WITH RESPECT TO THE TRACK OF
ISAAC AND ITS EVENTUAL REMNANTS AS IT WILL BE DEPENDENT HOW IT
INTERACTS WITH AN UPPER LEVEL TROUGH THAT WILL BE APPROACHING THE
EAST COAST.
WEDNESDAY...THIS UPPER LEVEL TROUGH AND AN ASSOCIATED SURFACE
FRONT WILL PROVIDE A FOCUS FOR PRECIPITATION ACROSS CENTRAL NORTH
CAROLINA. MODELS DO AGREE ON A PLUME OF DEEP TROPICAL MOISTURE
BEING OVER THE REGION DURING THIS TIME FRAME...WITH PRECIPITABLE
WATER VALUES FORECAST TO EXCEED 2 INCHES (ESPECIALLY ACROSS THE
SOUTHEASTERN PORTION OF THE FORECAST AREA). AS A RESULT...WILL
MAINTAIN HIGH END CHANCE POPS...HIGHEST ACROSS THE SOUTHEASTERN
CWA. BEYOND WEDNESDAY...FORECAST UNCERTAINTY INCREASES AS OUR RAIN
CHANCES WILL HINGE ON THE TRACK OF THE REMNANTS OF ISAAC. THE GFS
CONTINUES TO BE FURTHER WEST...AS THE AFOREMENTIONED UPPER LEVEL
TROUGH MOVES OFFSHORE FASTER AND THEREFORE THERE IS LITTLE
INTERACTION BETWEEN IT AND ISAAC. AS A RESULT...THE REMNANT LOW
TRACKS WEST OF THE MS RIVER VALLEY AND EVENTUALLY EASTWARD LATE
NEXT WEEKEND AS IT IS PICKED UP BY THE NEXT TROUGH. THIS SOLUTION
WOULD LEAVE CENTRAL NORTH CAROLINA FAIRLY DRY FOR THE LATTER HALF
OF THE PERIOD...AS A MID LEVEL HIGH BUILDS OVER THE REGION.
HOWEVER...THE ECMWF IS SLIGHTLY SLOWER WITH THE PROGRESSION OF THE
UPPER LEVEL TROUGH..WHICH RESULTS IN INTERACTION BETWEEN ISAAC AND
THE UPPER LEVEL TROUGH...THEREFORE PULLING THE REMNANT LOW MORE
NORTHWARD AND TRACKS IT SOMEWHERE BETWEEN THE MISSISSIPPI VALLEY
AND THE APPALACHIANS (ALTHOUGH IT HAS ALSO BEEN TRENDING WESTWARD
DURING THE PAST SEVERAL RUNS). THIS SOLUTION WOULD RESULT IN A
LONGER PERIOD OF RAIN CHANCES FOR THE REGION. DUE TO THE
UNCERTAINTY...WILL MAINTAIN FORECAST CONTINUITY AND WILL SHOW A
GRADUAL TREND OF DECREASING POPS AFTER WEDNESDAY...BUT WILL KEEP
AT LEAST A SLIGHT CHANCE IN FOR THE ENTIRE PERIOD. AFTER HIGHS
ONLY NEAR 80 DEGREES ON WEDNESDAY... MAXIMUM TEMPERATURES WILL
TREND UPWARDS THROUGH THE REMAINDER OF THE PERIOD...WITH UPPER 80S
EXPECTED BY THE END OF NEXT WEEKEND. OVERNIGHT LOWS WILL GENERALLY
BE IN THE UPPER 60S TO LOWER 70S THROUGHOUT THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 210 PM MONDAY...
VFR CONDITIONS ARE PREDOMINATE ACROSS CENTRAL NC THIS AFTERNOON WITH
SCT-BKN CUMULUS WITH BASES OF 3-5KFT. A WESTWARD MOVING COASTAL
FRONT ENHANCED BY SEA BREEZE AND CONVECTIVE BOUNDARIES WILL MOVE
ACROSS THE COASTAL PLAIN THIS AFTERNOON AND COULD BRING A SHORT
PERIOD OF MVFR CIGS/VSBYS IN A RAIN SHOWER. FAIR WEATHER WITH MAINLY
SCT LOW/MID LEVEL CLOUDS IS EXPECTED ELSEWHERE THIS AFTERNOON. FAIR
WEATHER IS EXPECTED EVERYWHERE THIS EVENING AND DURING THE EARLY
OVERNIGHT HOURS BEFORE AREAS OF MORNING STRATUS AND SOME FOG DEVELOP
TOWARD DAYBREAK. HAVE HIGHLIGHTED POTENTIAL FOR A BRIEF PERIOD OF
IFR/LIFR CONDITIONS WITH FOG/STRATUS AT KRWI TUESDAY MORNING WITH
MAINLY MVFR CONDITIONS EXPECTED ELSEWHERE. BKN CLOUDINESS WITH BASES
RANGING FROM 3KFT EAST TO 5KFT WEST ARE EXPECTED ON TUESDAY.
THE WEATHER DURING THE EXTENDED RANGE WILL LARGELY DEPEND ON THE
EVOLUTION OF TROPICAL CYCLONE ISAAC AND A COLD FRONT THAT WILL MOVE
ACROSS THE AREA LATE TUESDAY AND WEDNESDAY. THIS SURFACE BOUNDARY IS
PREDICTED TO STALL OVER THE CAROLINAS. AT THIS TIME... A PERIOD OF
ADVERSE AVIATION CONDITIONS MAY IMPACT THE AREA FROM LATE TUESDAY
THROUGH THURSDAY WITH SUB VFR CEILINGS AS WELL AS SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. MORE WIDELY SCATTERED SHOWERS
WITH A REDUCED POTENTIAL FOR ADVERSE IMPACT IS EXPECTED ON FRIDAY
AND SATURDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
340 PM EDT MON AUG 27 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY...BEFORE WEAKENING
TONIGHT. AS TROPICAL CYCLONE ISAAC APPROACHES THE NORTHERN GULF
COAST ON TUESDAY...THE DEEP TROPICAL MOISTURE PLUME WILL SPREAD
NORTHWARD INTO THE CAROLINAS...WHERE IT WILL INTERACT WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST LATE TUESDAY OR TUESDAY
NIGHT. THE SLOW MOVING COLD FRONT COULD POTENTIALLY STALL ACROSS
THE AREA ON WEDNESDAY...BEFORE FINALLY SHIFTING SOUTH OF THE AREA
ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 PM EDT...
LATEST SURFACE ANALYSIS SHOWS TROPICAL STORM ISAAC IN THE
EAST-CENTRAL GULF OF MEXICO. A SOUTHEASTERLY LOW LEVEL FLOW OFF THE
ATLANTIC ASSOCIATED WITH ISAAC COMBINED WITH A NARROW RIDGE OF HIGH
PRESSURE EXTENDING SOUTHWESTWARD ACROSS THE WESTERN PIEDMONT OF VA
AND NC HAS RESULTED IN THE DEVELOPMENT OF AN INLAND PENETRATING
COASTAL FRONT. THE FRONT HAS BEEN ENHANCED BY SEA BREEZE BOUNDARIES
ACROSS SOUTHERN COASTAL AREAS AND WITH CONVECTIVE OUTFLOW ACROSS THE
CENTRAL COASTAL AREA. AN AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS IS ASSOCIATED WITH THE BOUNDARY...ELSEWHERE FAIR
WEATHER WITH SCT-BKN CUMULUS IS WIDESPREAD ACROSS THE REMAINDER OF
CENTRAL NORTH CAROLINA.
THE CONVECTION IS EXPECTED TO CONTINUE ADVANCING NORTHWEST THIS
AFTERNOON AND EARLY EVENING. AIDED BY A WEAKLY UNSTABLE AIR MASS
WITH MLCAPE VALUES RANGING FROM 500-1000 J/KG AND ONLY MODEST MID
LEVEL LAPSE RATES. THE CONVECTION IS EXPECTED TO DECREASE IN
COVERAGE AND INTENSITY AS IT MOVES FURTHER INLAND TOWARD THE SFC
RIDGE AND INTO A REGION OF DEW POINTS IN THE MID/UPPER 60S AND
RESULTANT MLCAPE VALUES OF LESS THAN 500 J/KG. THIS TREND IS
SUPPORTED BY RECENT HRRR RUNS WHICH HAS HANDLED THIS WELL. THE
PRECIPITATION MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS THE
SOUTHERN COASTAL PLAIN/SANDHILLS/SOUTHERN PIEDMONT BEFORE FAIR
WEATHER ARRIVES ACROSS CENTRAL LATE THIS EVENING AND OVERNIGHT.
ANOTHER ROUND OF STRATUS AND FOG IS EXPECTED TO DEVELOP LATE
TONIGHT. WITH A SUB-TROPICAL AIR MASS IN PLACE ACROSS THE
REGION...LOWS TONIGHT SHOULD FALL INTO THE 67-72 RANGE FROM WEST TO
EAST. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM MONDAY...
AS AFOREMENTIONED NORTHERN STREAM TROUGH ADVANCES EAST THROUGH THE
NORTHEAST UNITED STATES ON TUESDAY...TRAILING SURFACE COLD FRONT
WILL MOVE SLOWLY EAST SOUTHEAST INTO THE AREA TUESDAY AFTERNOON
AND TUESDAY EVENING... WHERE MODELS SUGGEST IT COULD STALL THROUGH
THURSDAY. WHILE MOISTURE IS CURRENTLY LIMITED WITH THE COLD
FRONT...THE INTERACTION OF THE FRONT WITH THE NORTHERN PERIPHERY
OF THE EXPANSIVE TROPICAL MOISTURE PLUME ASSOCIATED WITH THE LARGE
WIND FIELD OF ISAAC COULD RESULT IN THE POTENTIAL FOR HEAVY RAIN
ACROSS THE CAROLINAS LATE TUESDAY AFTERNOON AND TUESDAY NIGHT...
ESPECIALLY IN THE UPSLOPE AREAS ALONG THE EASTERN SLOPES AND
ACROSS SOUTHERN PORTIONS OF THE STATE WHERE PRECIPITABLE WATERS
ARE EXPECTED TO BE ABOVE TWO INCHES.
IT REMAINS IMPORTANT TO NOTE THAT THIS HEAVY RAIN POTENTIAL WILL
ULTIMATELY DEPEND ON THE TRACK OF ISAAC...WITH ANY WESTWARD DEVIATION
TO THE FORECAST TRACK REDUCING THE HEAVY RAINFALL THREAT. SO AS YOU
CAN SEE...THERE IS STILL LOTS OF UNCERTAINTY AT THIS TIME.. AS SUCH
WILL KEEP POPS IN 40 TO 50 PERCENT CHANCE CATEGORIES. AS FAR AS A
SEVERE THREAT...THERE ARE QUESTIONS ABOUT HOW EXTENSIVE CLOUD COVER
WILL BE DURING THE DAY ON TUESDAY AND HOW IT MAY LIMIT
DESTABILIZATION...BUT SOME OF THE MODELS STILL DEVELOP MODERATE
INSTABILITY ACROSS THE SOUTH/SOUTHEAST. WINDS ALOFT ARE FAIRLY
WEAK...15 TO 20 KNOTS...SO DO NOT EXPECT MUCH MORE THAN AN ISOLATED
SEVERE THREAT TUESDAY AFTERNOON.
HIGHS TUESDAY GENERALLY IN THE LOWER TO MID 80S. OVERNIGHT LOWS
IN THE UPPER 60S ACROSS THE NORTH TO LOWER TO MID 70S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
THERE IS STILL A GREAT DEAL OF UNCERTAINTY FOR THE LONG TERM PERIOD
AS MUCH OF OUR WEATHER WILL ULTIMATELY DEPEND ON THE TRACK OF ISAAC
AND ITS EVENTUAL REMNANTS. THE OFFICIAL NATIONAL HURRICANE CENTER
TRACK HAS ISAAC MAKING LANDFALL SOUTH OF NEW ORLEANS LATE TUESDAY.
HOWEVER...MODELS CONTINUE TO STRUGGLE WITH RESPECT TO THE TRACK OF
ISAAC AND ITS EVENTUAL REMNANTS AS IT WILL BE DEPENDENT HOW IT
INTERACTS WITH AN UPPER LEVEL TROUGH THAT WILL BE APPROACHING THE
EAST COAST.
WEDNESDAY...THIS UPPER LEVEL TROUGH AND AN ASSOCIATED SURFACE
FRONT WILL PROVIDE A FOCUS FOR PRECIPITATION ACROSS CENTRAL NORTH
CAROLINA. MODELS DO AGREE ON A PLUME OF DEEP TROPICAL MOISTURE
BEING OVER THE REGION DURING THIS TIME FRAME...WITH PRECIPITABLE
WATER VALUES FORECAST TO EXCEED 2 INCHES (ESPECIALLY ACROSS THE
SOUTHEASTERN PORTION OF THE FORECAST AREA). AS A RESULT...WILL
MAINTAIN HIGH END CHANCE POPS...HIGHEST ACROSS THE SOUTHEASTERN
CWA. BEYOND WEDNESDAY...FORECAST UNCERTAINTY INCREASES AS OUR RAIN
CHANCES WILL HINGE ON THE TRACK OF THE REMNANTS OF ISAAC. THE GFS
CONTINUES TO BE FURTHER WEST...AS THE AFOREMENTIONED UPPER LEVEL
TROUGH MOVES OFFSHORE FASTER AND THEREFORE THERE IS LITTLE
INTERACTION BETWEEN IT AND ISAAC. AS A RESULT...THE REMNANT LOW
TRACKS WEST OF THE MS RIVER VALLEY AND EVENTUALLY EASTWARD LATE
NEXT WEEKEND AS IT IS PICKED UP BY THE NEXT TROUGH. THIS SOLUTION
WOULD LEAVE CENTRAL NORTH CAROLINA FAIRLY DRY FOR THE LATTER HALF
OF THE PERIOD...AS A MID LEVEL HIGH BUILDS OVER THE REGION.
HOWEVER...THE ECMWF IS SLIGHTLY SLOWER WITH THE PROGRESSION OF THE
UPPER LEVEL TROUGH..WHICH RESULTS IN INTERACTION BETWEEN ISAAC AND
THE UPPER LEVEL TROUGH...THEREFORE PULLING THE REMNANT LOW MORE
NORTHWARD AND TRACKS IT SOMEWHERE BETWEEN THE MISSISSIPPI VALLEY
AND THE APPALACHIANS (ALTHOUGH IT HAS ALSO BEEN TRENDING WESTWARD
DURING THE PAST SEVERAL RUNS). THIS SOLUTION WOULD RESULT IN A
LONGER PERIOD OF RAIN CHANCES FOR THE REGION. DUE TO THE
UNCERTAINTY...WILL MAINTAIN FORECAST CONTINUITY AND WILL SHOW A
GRADUAL TREND OF DECREASING POPS AFTER WEDNESDAY...BUT WILL KEEP
AT LEAST A SLIGHT CHANCE IN FOR THE ENTIRE PERIOD. AFTER HIGHS
ONLY NEAR 80 DEGREES ON WEDNESDAY... MAXIMUM TEMPERATURES WILL
TREND UPWARDS THROUGH THE REMAINDER OF THE PERIOD...WITH UPPER 80S
EXPECTED BY THE END OF NEXT WEEKEND. OVERNIGHT LOWS WILL GENERALLY
BE IN THE UPPER 60S TO LOWER 70S THROUGHOUT THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 210 PM MONDAY...
VFR CONDITIONS ARE PREDOMINATE ACROSS CENTRAL NC THIS AFTERNOON WITH
SCT-BKN CUMULUS WITH BASES OF 3-5KFT. A WESTWARD MOVING COASTAL
FRONT ENHANCED BY SEA BREEZE AND CONVECTIVE BOUNDARIES WILL MOVE
ACROSS THE COASTAL PLAIN THIS AFTERNOON AND COULD BRING A SHORT
PERIOD OF MVFR CIGS/VSBYS IN A RAIN SHOWER. FAIR WEATHER WITH MAINLY
SCT LOW/MID LEVEL CLOUDS IS EXPECTED ELSEWHERE THIS AFTERNOON. FAIR
WEATHER IS EXPECTED EVERYWHERE THIS EVENING AND DURING THE EARLY
OVERNIGHT HOURS BEFORE AREAS OF MORNING STRATUS AND SOME FOG DEVELOP
TOWARD DAYBREAK. HAVE HIGHLIGHTED POTENTIAL FOR A BRIEF PERIOD OF
IFR/LIFR CONDITIONS WITH FOG/STRATUS AT KRWI TUESDAY MORNING WITH
MAINLY MVFR CONDITIONS EXPECTED ELSEWHERE. BKN CLOUDINESS WITH BASES
RANGING FROM 3KFT EAST TO 5KFT WEST ARE EXPECTED ON TUESDAY.
THE WEATHER DURING THE EXTENDED RANGE WILL LARGELY DEPEND ON THE
EVOLUTION OF TROPICAL CYCLONE ISAAC AND A COLD FRONT THAT WILL MOVE
ACROSS THE AREA LATE TUESDAY AND WEDNESDAY. THIS SURFACE BOUNDARY IS
PREDICTED TO STALL OVER THE CAROLINAS. AT THIS TIME... A PERIOD OF
ADVERSE AVIATION CONDITIONS MAY IMPACT THE AREA FROM LATE TUESDAY
THROUGH THURSDAY WITH SUB VFR CEILINGS AS WELL AS SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. MORE WIDELY SCATTERED SHOWERS
WITH A REDUCED POTENTIAL FOR ADVERSE IMPACT IS EXPECTED ON FRIDAY
AND SATURDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
344 PM CDT MON AUG 27 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...
SIGNIFICANT FIRE WEATHER CONCERNS CONTINUE THROUGH THE SHORT TERM
PERIOD. SEE DISCUSSION BELOW FOR DETAILS. OTHER THAN FIRE
WEATHER...MAIN CONCERNS ARE POTENTIAL FOR ELEVATED STORMS TONIGHT.
A 30 TO 40 KT LOW LEVEL JET MAY SUPPORT STORMS FROM LATE EVENING
THROUGH THE OVERNIGHT HOURS...ESPECIALLY THROUGH THE JAMES RIVER
VALLEY AND NORTH NEAR THE TURTLE MOUNTAINS. THE 18Z NAM12 AND THE
MOST RECENT HRRR BOTH DEVELOP STORMS IN THIS AREA BY 06Z THIS
EVENING. THE MAIN THREAT WOULD BE ISOLATED LARGE HAIL AROUND
QUARTER SIZE. FOR TUESDAY...HAVE OPTED TO REMOVE POPS THROUGH THE
DAY. EXPECT CONTINUED WARMING...WITH HIGHS REACHING THE 90S MOST
LOCATIONS...AND PERHAPS THE 100 DEGREE MARK IN THE FAR SOUTHWEST.
.LONG TERM...WEDNESDAY THROUGH MONDAY...
HIGHLIGHTS OF THE LONG TERM WILL BE HOT CONDITIONS ON WEDNESDAY
WITH THE POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS WEDNESDAY
INTO THURSDAY.
A VERY WARM WEDNESDAY IS EXPECTED ACROSS WESTERN AND CENTRAL NORTH
DAKOTA IN THE WARM SECTOR OF A SURFACE LOW ACROSS SOUTHEAST
SASKATCHEWAN. WIDESPREAD HIGHS IN THE UPPER 90S ARE FORECAST FOR
MUCH OF THE AREA...WITH LOWER 100S POSSIBLE ACROSS THE SOUTHWEST
WHERE WINDS DO BEGIN TO DOWN SLOPE AS THEY TURN SOUTHWEST AHEAD OF
AN APPROACHING COLD FRONT. THIS COLD FRONT IS FORECAST TO ENTER
THE FAR WEST BY WEDNESDAY EVENING AND EXIT THE CWA BY LATE
THURSDAY MORNING. SEE THE FIRE WEATHER DISCUSSION BELOW IN REGARDS
TO THE POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS BOTH AHEAD
OF AND BEHIND THE FRONT WEDNESDAY AND WEDNESDAY NIGHT.
THEREAFTER...TEMPERATURES TREND NEAR NORMAL FOR THE REMAINDER OF
THE EXTENDED. IN REGARDS TO PRECIPITATION...OTHER THAN VERY
ISOLATED CONVECTION WEDNESDAY EVENING AND NIGHT WITH COLD FRONTAL
PASSAGE...THE NEXT BEST CHANCE OF CONVECTION IS SATURDAY WITH THE
APPROACH OF THE NEXT UPPER LEVEL WAVE. HOWEVER...THIS MAY BE
DEPENDENT UPON THE TRACK AND INTERACTION OF THE REMNANTS OF ISAAC
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD FOR ALL
TERMINALS. THERE IS A SLIGHT CHANCE THUNDERSTORMS COULD IMPACT
KBIS/KJMS STARTING LATE MONDAY EVENING...HOWEVER...THERE IS SOME
UNCERTAINTY IN COVERAGE AND EXACT TIMING.
&&
.FIRE WEATHER...
A PROLONGED PERIOD OF POTENTIALLY CRITICAL FIRE WEATHER CONDITIONS
IS POSSIBLE THIS AFTERNOON THROUGH AT LEAST WEDNESDAY NIGHT.
FOR THE REMAINDER OF TODAY...A RED FLAG WARNING REMAINS IN EFFECT
FOR BOWMAN...SLOPE...GOLDEN VALLEY...BILLINGS...MCKENZIE AND STARK
COUNTIES UNTIL 9 PM MDT. SOUTHEAST WINDS TO 25 MPH WILL CONTINUE
THROUGH THE EVENING...WITH RELATIVE HUMIDITIES NEAR 20 PERCENT AND
TEMPERATURES NEAR 90. SOUTHEAST WINDS WILL DECREASE TO 10 MPH
AFTER SUNSET WITH RELATIVE HUMIDITIES RECOVERING TO NEAR 80
PERCENT TONIGHT.
FOR TUESDAY IN THE FAR SOUTHWEST...HIGHS WILL BE IN THE UPPER 90S
WITH AFTERNOON RELATIVE HUMIDITIES AROUND 15 PERCENT. WINDS AT 10
MPH OR LESS MAY BE HIGHLY VARIABLE IN DIRECTION...WHICH COULD
CAUSE FIRE CONTROL ISSUES PER COORDINATION WITH ND FIRE PERSONNEL.
FOR WEDNESDAY...CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE
ALONG AND WEST OF HIGHWAY 83. HIGHS NEAR 100...WINDS SOUTH AROUND
20 MPH AND RELATIVE HUMIDITIES NEAR 20 PERCENT ARE POSSIBLE. A
COLD FRONT MOVING THROUGH NORTH DAKOTA WEDNESDAY EVENING MAY
RESULT IN MIXING SUFFICIENT TO MAINTAIN LOW RELATIVE HUMIDITIES
THROUGH THE NIGHT. WINDS WILL SHIFT WEST BEHIND THE FRONT.
ISOLATED THUNDERSTORMS WITH DRY LIGHTNING ARE ALSO POSSIBLE
WEDNESDAY EVENING AND NIGHT. CONDITIONS WEDNESDAY EVENING AND
NIGHT WILL BE SIMILIAR TO THOSE SEEN ON FRIDAY NIGHT. FIRE WEATHER
CONCERNS MAY CONTINUE INTO THURSDAY FOR PORTIONS OF THE
AREA...HOWEVER...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES FOR
NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
MORNING FOR NDZ001>003-009>011-017>021-031>035-040>046.
RED FLAG WARNING UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR
NDZ017-031>033-040-043.
FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR NDZ031-032-040-043.
&&
$$
SHORT TERM...RK
LONG TERM/AVIATION/FIRE....AYD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
534 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS TO THE REGION THIS AFTERNOON AND
OVERNIGHT. COOLER DRIER AIR BUILDS IN BEHIND THE FRONT AS DOES A
SURFACE ANTICYCLONE IN THE NORTHWESTERLY FLOW. TOWARD THE END OF
THE WEEK A 5940M CLOSED HIGH BUILDS JUST TO OUR SOUTH AND A SURGE
OF VERY WARM AIR MOVES INTO THE REGION IMPLYING VERY WARM WEATHER
THURSDAY THROUGH AT LEAST SATURDAY. MOISTURE VALUES ARE LOW SO THE
HEAT LATER THIS WEEK AND WEEKEND SHOULD BE WITH RELATIVELY DRY
AIR.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
LIGHT RAIN AND SHOWERS ARE IN EXTREME NORTHWESTERN WARREN COUNTY
AND WORKING SLOWLY TO THE EAST. RATHER SUNNY IN CENTRAL
PENNSYLVANIA AND INTO THE SUSQUEHANNA VALLEY.
MOST GUIDANCE SUGGESTS RAIN WILL SLOWLY WORK ITS WAY EAST AND THUS
MOST CENTRAL AND EASTERN AREAS SHOULD REMAIN RAIN FREE UNTIL AFTER
DARK.
NOT A LOT OF INSTABILITY BUT SO SHOWERS WILL DOMINATE WITH SOME
ISOLATED EMBEDDED THUNDERSTORMS. THE SECOND AREA OF RAIN OVER OHIO
AND SOUTHERN LAKE ERIE WILL LIKELY BE THE FEATURE TO ENSURE BETTER
RAIN...PUT NEAR 100 PERCENT CHANCE IN NORTHWESTERN AREAS...THIS
EVENING. FEATURE AS AN VORTEX LIKE APPEARANCE TOO. LEANED TOWARD
THE 4KM NAM AT 1200 UTC AND SREF FOR SOLUTION. HRRR LOOKED A BIT
OVER DONE.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH TUESDAY NIGHT/...
BLENDED MODELS AND SREF TO GET POPS/QPF AFTER 0000 UTC. KEPT VERY
HIGH POPS IN NORTH AND LOWER POPS IN SOUTH...LOWEST IN SOUTHEAST.
THE FRONT IS MORE SW TO NE IN ORIENTATION AND ALL FORECAST SYSTEMS
SHOW VERY LOW QPF AND POPS AS ONE MOVES SOUTH AND EAST INTO PA.
QPF ABOUT 0.50 OR MORE MOST LIKELY IN NORTHERN REGIONS AND NOT
MUCH TO SPEAK OF IN SOUTHEAST.
LIKED 0900 UTC SREF AND 4KM NAM CLEARING OUT MOST OF THE CLOUDS NW
TO SE AFTER 0600 UTC AND GETTING MOST MENTION OF POPS OUT EVEN IN
EAST A FEW HOURS EITHER SIDE OF 1200 UTC TUESDAY.
PUT SOME FOG IN NORTHWEST TOWARD SUNRISE BEHIND THE FRONT AND IN
REGION WHERE EXPECT HIGHEST PROBABILITY OF RAINFALL AND THUS
MOISTURE IN THE BOUNDARY LAYER.
AFTERNOON LOOKS REALLY GOOD EVERYWHERE TUESDAY SO DROPPED ANY POPS
TO GENERATE SHOWERS AFTER ABOUT 1500 UTC. SHOULD BE WARM IN
SOUTHEAST INTO AFTERNOON. BUT VERY PLEASANT ACROSS REGION TOWARD
EVENING WITH LOWERED DEW POINTS AND LIGHT WINDS. THOSE WANTING
REAL HEAT WILL HAVE TO WAIT UNTIL PERHAPS FRIDAY AFTERNOON!
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
CONFIDENCE IN THE FIRST PART OF THE FCST PERIOD REMAINS ABOVE
AVERAGE...AS ALL MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE BUILDS
A SFC HIGH PRES AND ABNORMALLY DRY /BLW NORMAL PWAT/ AIR FROM THE
GREAT LAKES REGION SEWD ACROSS THE MID-ATLANTIC STATES. THIS WILL
RESULT IN FAIR AND DRY WX WED-FRI...WITH INCREASINGLY HOT CONDS
EXPECTED BY THE END OF THE WEEK. IN FACT...THERE IS A CLEAR TREND
TOWARD A BRIEF HEAT WAVE AROUND THE END OF THE WEEK...AS AN
ANOMALOUS H5 RIDGE MIGRATES ATOP OF THE TROPICAL CYCLONE. 12Z GEFS
AND 00Z ECMWF ENSEMBLE DATA BOTH SHOW 850MB TEMPS ARND 18-20C BY
FRI-SAT...AND THEREFORE BOOSTED MAXES A FEW DEGS ABV MOS GUID
AND CLOSER TO THE 18Z HPC FINALS. REASON BEING...THE INHERENT CLIMO
BIAS IS LKLY HOLDING MOS TEMPS DOWN TOO LOW. THIS SHOULD TRANSLATE
INTO 90F DEGREE TEMPS IN THE CENTRAL AND SOUTHEASTERN VALLEYS.
THE NRN STREAM FLOW ALOFT SHOULD BECOME MORE PROGRESSIVE/ZONAL
DURING THE SECOND HALF OF THE PERIOD...AS THE H5 RIDGE SHIFTS OFF
THE SE COAST. THIS WOULD ALLOW THE TRANSITIONING TROPICAL CYCLONE
AND ASSOCIATED MOISTURE TO GET PICKED UP IN THE WESTERLIES...WITH
SOME RE-CURVATURE AND EWD ACCELERATION POSSIBLE BY THE END OF THE
WEEKEND. THE FASTER FLOW ALOFT COMBINED WITH THE INFLUENCE OF
ISSAC LEADS TO BELOW AVG CONFIDENCE...AS THE MODELS BECOME OUT OF
PHASE INTO EARLY NEXT WEEK. THEREFORE...UTILIZED A BLENDED SOLUTION
COMPRISED OF EC/GFS/HPC GRIDDED DATA FOR DAYS 6-8 /SAT-MON/. IN
GENERAL EXPECT A MORE UNSETTLED PATTERN TO UNFOLD WITH AN
INCREASED CHANCE FOR RAIN AND OTHER POTENTIAL IMPACTS ASSOC WITH
THE REMNANTS OF ISAAC.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
COLD FRONT IN E OHIO IS CREATING LARGE AREA OF SHOWERS/LIGHT RAIN
IN W PA AND NORTHERN MTNS. MUCH OF AREA NORTH OF I-80 SEEIGN
SHOWERS...WITH ISO TSTMS DEVELOPING NEAR/NORTH OF KIPT AT 22Z.
PRECIP WILL GRADUALLY WORK INTO SW AREAS OVER NEXT SEVERAL
HOURS...BUT TAKE MOST OF THE NIGHT TO GET INTO EXTREME
SOUTHEASTERN AREAS.
BEHIND THE FRONT LATER TONIGHT...NORTHWEST AREAS WILL HAVE MORE
FOG THAN SOUTHEAST /WITH ADDITIONAL MOISTURE DUE TO RAINFALL/. MOST
OF TAFS SHOW LIGHT RAIN BY 03-06Z OR BR AS RAIN LOOKS SPOTTY AS ONE
MOVES SOUTH AND EAST INTO PENNSYLVANIA.
IMPROVING...IF NOT RAPIDLY IMPROVING...CONDITIONS TUESDAY MORNING
AS CLOUDS WITH FRONTAL BOUNDARY SLIDE TO OUR EAST AND PATCHY FOG
IN MORNING BURNS OFF. SHOULD BE MVFR/VFR EVERYWHERE BY 14Z AND VFR
EVERYWHERE BY 1700 UTC.
COMING WEEK LOOKS GOOD PATCH AM FOG AND SUNNY SKIES. NO WEATHER OF
NOTE EXPECTED UNTIL THE WEEKEND OR LATER...BIG BUBBLE NO TROUBLE.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR POSSIBLE MVFR/IFR PATCH AM FOG.
SAT...MVFR POSS IN SCT RAIN SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...STEINBUGL
AVIATION...GRUMM/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
354 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS TO THE REGION THIS AFTERNOON AND
OVERNIGHT. COOLER DRIER AIR BUILDS IN BEHIND THE FRONT AS DOES A
SURFACE ANTICYCLONE IN THE NORTHWESTERLY FLOW. TOWARD THE END OF
THE WEEK A 5940M CLOSED HIGH BUILDS JUST TO OUR SOUTH AND A SURGE
OF VERY WARM AIR MOVES INTO THE REGION IMPLYING VERY WARM WEATHER
THURSDAY THROUGH AT LEAST SATURDAY. MOISTURE VALUES ARE LOW SO THE
HEAT LATER THIS WEEK AND WEEKEND SHOULD BE WITH RELATIVELY DRY
AIR.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
LIGHT RAIN AND SHOWERS ARE IN EXTREME NORTHWESTERN WARREN COUNTY
AND WORKING SLOWLY TO THE EAST. RATHER SUNNY IN CENTRAL
PENNSYLVANIA AND INTO THE SUSQUEHANNA VALLEY.
MOST GUIDANCE SUGGESTS RAIN WILL SLOWLY WORK ITS WAY EAST AND THUS
MOST CENTRAL AND EASTERN AREAS SHOULD REMAIN RAIN FREE UNTIL AFTER
DARK.
NOT A LOT OF INSTABILITY BUT SO SHOWERS WILL DOMINATE WITH SOME
ISOLATED EMBEDDED THUNDERSTORMS. THE SECOND AREA OF RAIN OVER OHIO
AND SOUTHERN LAKE ERIE WILL LIKELY BE THE FEATURE TO ENSURE BETTER
RAIN...PUT NEAR 100 PERCENT CHANCE IN NORTHWESTERN AREAS...THIS
EVENING. FEATURE AS AN VORTEX LIKE APPEARANCE TOO. LEANED TOWARD
THE 4KM NAM AT 1200 UTC AND SREF FOR SOLUTION. HRRR LOOKED A BIT
OVER DONE.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH TUESDAY NIGHT/...
BLENDED MODELS AND SREF TO GET POPS/QPF AFTER 0000 UTC. KEPT VERY
HIGH POPS IN NORTH AND LOWER POPS IN SOUTH...LOWEST IN SOUTHEAST.
THE FRONT IS MORE SW TO NE IN ORIENTATION AND ALL FORECAST SYSTEMS
SHOW VERY LOW QPF AND POPS AS ONE MOVES SOUTH AND EAST INTO PA.
QPF ABOUT 0.50 OR MORE MOST LIKELY IN NORTHERN REGIONS AND NOT
MUCH TO SPEAK OF IN SOUTHEAST.
LIKED 0900 UTC SREF AND 4KM NAM CLEARING OUT MOST OF THE CLOUDS NW
TO SE AFTER 0600 UTC AND GETTING MOST MENTION OF POPS OUT EVEN IN
EAST A FEW HOURS EITHER SIDE OF 1200 UTC TUESDAY.
PUT SOME FOG IN NORTHWEST TOWARD SUNRISE BEHIND THE FRONT AND IN
REGION WHERE EXPECT HIGHEST PROBABILITY OF RAINFALL AND THUS
MOISTURE IN THE BOUNDARY LAYER.
AFTERNOON LOOKS REALLY GOOD EVERYWHERE TUESDAY SO DROPPED ANY POPS
TO GENERATE SHOWERS AFTER ABOUT 1500 UTC. SHOULD BE WARM IN
SOUTHEAST INTO AFTERNOON. BUT VERY PLEASANT ACROSS REGION TOWARD
EVENING WITH LOWERED DEW POINTS AND LIGHT WINDS. THOSE WANTING
REAL HEAT WILL HAVE TO WAIT UNTIL PERHAPS FRIDAY AFTERNOON!
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
CONFIDENCE IN THE FIRST PART OF THE FCST PERIOD REMAINS ABOVE
AVERAGE...AS ALL MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE BUILDS
A SFC HIGH PRES AND ABNORMALLY DRY /BLW NORMAL PWAT/ AIR FROM THE
GREAT LAKES REGION SEWD ACROSS THE MID-ATLANTIC STATES. THIS WILL
RESULT IN FAIR AND DRY WX WED-FRI...WITH INCREASINGLY HOT CONDS
EXPECTED BY THE END OF THE WEEK. IN FACT...THERE IS A CLEAR TREND
TOWARD A BRIEF HEAT WAVE AROUND THE END OF THE WEEK...AS AN
ANOMALOUS H5 RIDGE MIGRATES ATOP OF THE TROPICAL CYCLONE. 12Z GEFS
AND 00Z ECMWF ENSEMBLE DATA BOTH SHOW 850MB TEMPS ARND 18-20C BY
FRI-SAT...AND THEREFORE BOOSTED MAXES A FEW DEGS ABV MOS GUID
AND CLOSER TO THE 18Z HPC FINALS. REASON BEING...THE INHERENT CLIMO
BIAS IS LKLY HOLDING MOS TEMPS DOWN TOO LOW. THIS SHOULD TRANSLATE
INTO 90F DEGREE TEMPS IN THE CENTRAL AND SOUTHEASTERN VALLEYS.
THE NRN STREAM FLOW ALOFT SHOULD BECOME MORE PROGRESSIVE/ZONAL
DURING THE SECOND HALF OF THE PERIOD...AS THE H5 RIDGE SHIFTS OFF
THE SE COAST. THIS WOULD ALLOW THE TRANSITIONING TROPICAL CYCLONE
AND ASSOCIATED MOISTURE TO GET PICKED UP IN THE WESTERLIES...WITH
SOME RE-CURVATURE AND EWD ACCELERATION POSSIBLE BY THE END OF THE
WEEKEND. THE FASTER FLOW ALOFT COMBINED WITH THE INFLUENCE OF
ISSAC LEADS TO BELOW AVG CONFIDENCE...AS THE MODELS BECOME OUT OF
PHASE INTO EARLY NEXT WEEK. THEREFORE...UTILIZED A BLENDED SOLUTION
COMPRISED OF EC/GFS/HPC GRIDDED DATA FOR DAYS 6-8 /SAT-MON/. IN
GENERAL EXPECT A MORE UNSETTLED PATTERN TO UNFOLD WITH AN
INCREASED CHANCE FOR RAIN AND OTHER POTENTIAL IMPACTS ASSOC WITH
THE REMNANTS OF ISAAC.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
COLD FRONT BACK OVER OHIO IS CREATING SHOWERS AND LIGHT RAIN IN
NORTHWESTERN PENNSYLVANIA. LEADING EDGE COULD BE IN KBFD AROUND OR
SHORTLY AFTER 1800 UTC. WILL TAKE MOST OF THE REST OF THE DAY TO
WORK INTO THE SOUTHWESTERN AREAS. MOST OF THE NIGHT TO GET INTO
EXTREME SOUTHEASTERN AREAS.
NORTHWEST AREAS WILL HAVE MORE FOG THAN SOUTHEAST BEHIND THE FRONT
AND WITH ADDITIONAL MOISTURE DUE TO RAINFALL. MOST OF TAFS SHOW
LIGHT RAIN BY 3-0600 UTC OR BR AS RAIN LOOKS SPOTTY AS ONE MOVES
SOUTH AND EAST INTO PENNSYLVANIA.
IMPROVING...IF NOT RAPIDLY IMPROVING...CONDITIONS TUESDAY MORNING
AS CLOUDS WITH FRONTAL BOUNDARY SLIDE TO OUR EAST AND PATCHY FOG
IN MORNING BURNS OFF. SHOULD BE MVFR/VFR EVERYWHERE BY 14Z AND VFR
EVERYWHERE BY 1700 UTC.
COMING WEEK LOOKS GOOD PATCH AM FOG AND SUNNY SKIES. NO WEATHER OF
NOTE EXPECTED UNTIL THE WEEKEND OR LATER...BIG BUBBLE NO TROUBLE.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR POSSIBLE MVFR/IFR PATCH AM FOG.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...STEINBUGL
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
235 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS TO THE REGION THIS AFTERNOON AND
OVERNIGHT. COOLER DRIER AIR BUILDS IN BEHIND THE FRONT AS DOES A
SURFACE ANTICYCLONE IN THE NORTHWESTERLY FLOW. TOWARD THE END OF
THE WEEK A 5940M CLOSED HIGH BUILDS JUST TO OUR SOUTH AND A SURGE
OF VERY WARM AIR MOVES INTO THE REGION IMPLYING VERY WARM WEATHER
THURSDAY THROUGH AT LEAST SATURDAY. MOISTURE VALUES ARE LOW SO THE
HEAT LATER THIS WEEK AND WEEKEND SHOULD BE WITH RELATIVELY DRY
AIR.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
LIGHT RAIN AND SHOWERS ARE IN EXTREME NORTHWESTERN WARREN COUNTY
AND WORKING SLOWLY TO THE EAST. RATHER SUNNY IN CENTRAL
PENNSYLVANIA AND INTO THE SUSQUEHANNA VALLEY.
MOST GUIDANCE SUGGESTS RAIN WILL SLOWLY WORK ITS WAY EAST AND THUS
MOST CENTRAL AND EASTERN AREAS SHOULD REMAIN RAIN FREE UNTIL AFTER
DARK.
NOT A LOT OF INSTABILITY BUT SO SHOWERS WILL DOMINATE WITH SOME
ISOLATED EMBEDDED THUNDERSTORMS. THE SECOND AREA OF RAIN OVER OHIO
AND SOUTHERN LAKE ERIE WILL LIKELY BE THE FEATURE TO ENSURE BETTER
RAIN...PUT NEAR 100 PERCENT CHANCE IN NORTHWESTERN AREAS...THIS
EVENING. FEATURE AS AN VORTEX LIKE APPEARANCE TOO. LEANED TOWARD
THE 4KM NAM AT 1200 UTC AND SREF FOR SOLUTION. HRRR LOOKED A BIT
OVER DONE.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH TUESDAY NIGHT/...
BLENDED MODELS AND SREF TO GET POPS/QPF AFTER 0000 UTC. KEPT VERY
HIGH POPS IN NORTH AND LOWER POPS IN SOUTH...LOWEST IN SOUTHEAST.
THE FRONT IS MORE SW TO NE IN ORIENTATION AND ALL FORECAST SYSTEMS
SHOW VERY LOW QPF AND POPS AS ONE MOVES SOUTH AND EAST INTO PA.
QPF ABOUT 0.50 OR MORE MOST LIKELY IN NORTHERN REGIONS AND NOT
MUCH TO SPEAK OF IN SOUTHEAST.
LIKED 0900 UTC SREF AND 4KM NAM CLEARING OUT MOST OF THE CLOUDS NW
TO SE AFTER 0600 UTC AND GETTING MOST MENTION OF POPS OUT EVEN IN
EAST A FEW HOURS EITHER SIDE OF 1200 UTC TUESDAY.
PUT SOME FOG IN NORTHWEST TOWARD SUNRISE BEHIND THE FRONT AND IN
REGION WHERE EXPECT HIGHEST PROBABILITY OF RAINFALL AND THUS
MOISTURE IN THE BOUNDARY LAYER.
AFTERNOON LOOKS REALLY GOOD EVERYWHERE TUESDAY SO DROPPED ANY POPS
TO GENERATE SHOWERS AFTER ABOUT 1500 UTC. SHOULD BE WARM IN
SOUTHEAST INTO AFTERNOON. BUT VERY PLEASANT ACROSS REGION TOWARD
EVENING WITH LOWERED DEW POINTS AND LIGHT WINDS. THOSE WANTING
REAL HEAT WILL HAVE TO WAIT UNTIL PERHAPS FRIDAY AFTERNOON!
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A HIGH CONFIDENCE FCST WED-FRI...AS ALL MED RANGE GUIDANCE BUILDS
SFC HIGH AND LOW PWAT AIR SE ACROSS PA. THUS...ANTICIPATE MCLEAR
SKIES DURING THE SECOND HALF OF THE WEEK. ECMWF MEAN 8H TEMPS
INDICATE HIGHS NR AVERAGE WED...THEN A WARM-UP FOR LATE WEEK...AS HIGH
DRIFTS SE OF PA AND RETURN SW FLOW DEVELOPS. DRY AIR WILL LIKELY
RESULT IN A COUPLE OF COOL NIGHTS AT MIDWEEK...WITH WED NIGHT IN
PARTICULAR LOOKING COOL...AS SFC HIGH DRIFTS DIRECTLY OVR THE
STATE. GEFS AND ECMWF ENSEMBLE DATA BOTH PUSH 850MB TEMPS TO ARND
18C BY LATE WEEK...SO HAVE INCREASED HIGHS FRI/SAT TO NR 90F IN
THE VALLEYS.
AN ADDITIONAL CONCERN HEADING INTO NEXT WEEKEND IS THE REMNANTS
OF ISAAC. BULK OF MED RANGE GUIDANCE TAKE WHAT IS LEFT OF ISAAC
AND CURL IT UP AND OVER THE BUILDING UPPER LEVEL RIDGE NEXT
WEEKEND....WHICH COULD TURN OUR WEATHER UNSETTLED. DUE TO INHERENT
MDL UNCERTAINTIES SO FAR OUT...HAVE CONSERVATIVELY INCREASED POPS
TO ARND 40 PCT BY NEXT WEEKEND.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
COLD FRONT BACK OVER OHIO IS CREATING SHOWERS AND LIGHT RAIN IN
NORTHWESTERN PENNSYLVANIA. LEADING EDGE COULD BE IN KBFD AROUND OR
SHORTLY AFTER 1800 UTC. WILL TAKE MOST OF THE REST OF THE DAY TO
WORK INTO THE SOUTHWESTERN AREAS. MOST OF THE NIGHT TO GET INTO
EXTREME SOUTHEASTERN AREAS.
NORTHWEST AREAS WILL HAVE MORE FOG THAN SOUTHEAST BEHIND THE FRONT
AND WITH ADDITIONAL MOISTURE DUE TO RAINFALL. MOST OF TAFS SHOW
LIGHT RAIN BY 3-0600 UTC OR BR AS RAIN LOOKS SPOTTY AS ONE MOVES
SOUTH AND EAST INTO PENNSYLVANIA.
IMPROVING...IF NOT RAPIDLY IMPROVING...CONDITIONS TUESDAY MORNING
AS CLOUDS WITH FRONTAL BOUNDARY SLIDE TO OUR EAST AND PATCHY FOG
IN MORNING BURNS OFF. SHOULD BE MVFR/VFR EVERYWHERE BY 14Z AND VFR
EVERYWHERE BY 1700 UTC.
COMING WEEK LOOKS GOOD PATCH AM FOG AND SUNNY SKIES. NO WEATHER OF
NOTE EXPECTED UNTIL THE WEEKEND OR LATER...BIG BUBBLE NO TROUBLE.
OUTLOOK...
EARLY TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED-FRI...VFR POSSIBLE MVFR/IFR PATCH AM FOG.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...FITZGERALD/EVANEGO
AVIATION...GRUMM