Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/17/12
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
330 AM PDT SAT SEP 15 2012
.SYNOPSIS...
HIGH PRESSURE ALOFT AND OFFSHORE FLOW WILL RESULT IN ANOTHER VERY
HOT DAY TODAY. COOLING WILL BEGIN SUNDAY AS THE HIGH ALOFT WEAKENS
AND SURFACE FLOW BECOMES ONSHORE. LOCAL STRONG AND GUSTY EAST WINDS
WILL CONTINUE THROUGH AND BELOW MOUNTAIN PASSES AND CANYONS OF SAN
DIEGO COUNTY TODAY WITH LOW HUMIDITIES. COOLER WEATHER WILL CONTINUE
MONDAY AND TUESDAY WITH A COASTAL MARINE LAYER. HOWEVER...MOST AREAS
WILL CONTINUE TO HAVE TEMPERATURES ABOVE NORMAL MOST OF NEXT WEEK
DUE TO HIGH PRESSURE ALOFT CONTINUING.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THE VERY HOT WEATHER IS EXPECTED AGAIN TODAY...WITH TEMPERATURES
SIMILAR TO THOSE OF SATURDAY EXCEPT FOR HIGHER TEMPERATURES ALONG
THE IMMEDIATE COAST DUE TO A BIT MORE EAST FLOW THERE. SO...MOST
AREAS W OF THE MTNS WILL BE 100+...WITH MOSTLY 90S WITHIN A FEW
MILES OF THE COAST BEFORE THE AFTERNOON SEA BREEZE DEVELOPS. GOING
FOR 99 AT KSAN DUE TO MANY BUFKIT PROFILES...INCLUDING
SREF...SHOWING A NEARLY ADIABATIC SOUNDING BELOW 700 MB THROUGH
ABOUT 1 PM WHEN THE SEA BREEZE BEGINS. 06Z LOCAL WRF AND HRRR MODELS
INDICATE GUST POTENTIAL AROUND 35-38 MPH IN THE MTNS/FOOTHILLS
MAINLY OF CENTRAL SAN DIEGO COUNTY...THOUGH THIS IS DOWN SLIGHTLY
FROM PREVIOUS RUNS AS...AT LEAST IN THE WRF...THE 850 MB THERMAL
GRADIENT IS A BIT LESS STRONG OVER THE MTNS THAN PREVIOUSLY
INDICATED. WILL CONTINUE MENTION OF LOCAL GUSTS TO 40 MPH FOR FIRE
WEATHER PURPOSES...SEE FIRE WEATHER SECTION FOR MORE DETAILS.
SUNDAY WILL BE QUITE A CHANGE DUE TO SURFACE ONSHORE FLOW DEVELOPING
REGIONWIDE AND PROBABLY A WEAK EDDY. HENCE...COASTAL AREAS WILL BE
15-20 DEGREES COOLER WITH MOST OTHER AREAS 3 TO 10 DEGREES COOLER.
TIMING OF THE STRATUS WILL BE TRICKY AND BASED ON THE STRENGTH OF
THE EDDY AS THERE IS CURRENTLY STRATUS ALONG THE BAJA COAST STARTING
ABOUT 25 MILES S OF THE US/MEXICO BORDER. FOR NOW...EXPECT
STRATUS/FOG TO MOVE INTO THE COASTAL WATERS SUNDAY AND THEN SPREAD
ONTO LAND SUNDAY EVENING. THERE COULD BE A PERIOD OF DENSE FOG WITH
THE ONSET OF THE STRATUS/FOG...AS IS OFTEN THE CASE WHEN STRATUS/FOG
RETURNS AFTER A HEAT WAVE.
OVERALL...HIGH PRESSURE ALOFT WILL CONTINUE MOST OF NEXT WEEK...WITH
SOME RESTRENGTHENING AROUND WED/THU. THE POSITION OF THE HIGH WILL
BE SIMILAR TO THE CURRENT HIGH BUT NOT QUITE AS STRONG...SO IT WILL
MOST LIKELY NOT BE QUITE AS HOT IN SOCAL AS IT IS NOW. WE WILL HAVE
TO WATCH THE REMNANTS OF TROPICAL STORM KRISTY NOT TOO FAR TO THE
SOUTH/SOUTHWEST AS A LOW TO OUR SOUTH COULD ALLOW FOR SOME OFFSHORE
FLOW TO DEVELOP AND INCREASE TEMPS NEAR THE COAST AROUND
MIDWEEK...THOUGH THIS IS NOT EXPECTED TO BRING ANY SIGNIFICANT
MOISTURE TO THE AREA.
&&
.FIRE WEATHER...
THERE WILL BE AN ELEVATED POTENTIAL FOR WILD FIRE GROWTH THROUGH THIS
AFTERNOON...BUT WIDESPREAD AND PERSISTENT CRITICAL LEVELS ARE NOT
EXPECTED. LOCAL MODELS SHOW PEAK SUSTAINED WIND POTENTIAL THROUGH
AND BELOW THE PASSES AND CANYONS OF THE SAN DIEGO COUNTY MTNS OF 20
TO 30 MPH WITH SOME GUSTS AROUND 40 MPH POSSIBLE IN THE WINDIEST
SPOTS IN THE MID TO LATE MORNING. WINDS WILL BE WEAKER TOWARD THE
COAST. LOWEST RELATIVE HUMIDITIES WILL GENERALLY BE AT LOWER
ELEVATIONS IN THE VALLEYS THAN THE PEAK WINDS...WITH 8 TO 10 PERCENT
IN A FEW LOCATIONS...WITH THE MOUNTAINS HAVING MIN RH VALUES AROUND
10 TO 15 PERCENT...MOSTLY IN THE EARLY AFTERNOON. CRITICAL FIRE
WEATHER CONDITIONS WILL LIKELY DEVELOP LOCALLY FOR A FEW HOURS IN
THE LATE MORNING/EARLY AFTERNOON IN THE SAN DIEGO COUNTY MOUNTAINS
AND FOOTHILLS...MAINLY FROM INTERSTATE 8 NORTH TO HIGHWAY 78...BUT
THESE CONDITIONS ARE NOT EXPECTED TO PERSIST 6 HOURS OR MORE. WINDS
SHOULD WEAKEN GRADUALLY IN THE AFTERNOON AND MORE SUBSTANTIALLY THIS
EVENING. HUMIDITIES WILL BE HIGHER ON SUNDAY DUE TO DEVELOPING
ONSHORE FLOW.
&&
.AVIATION...
150930Z...HIGH PRESSURE OVER THE REGION WILL MAINTAIN VFR CONDS
THROUGH THE TAF PERIOD. OCCASIONAL MODERATE UP/DOWNDRAFTS WILL
ACCOMPANY GUSTY EASTERLY WINDS UP TO 20 KT AT THE SURFACE FOR THE
VALLEYS AND WEST OF THE MTNS THIS AFTERNOON.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
SPECIAL WEATHER STATEMENT FOR HOT WEATHER...SEE LAXSPSSGX.
&&
$$
PUBLIC/FIRE WEATHER...JAD
AVIATION...JJT
AREA FORECAST DISCUSSION
NWS NEW YORK NY
719 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A COLD FRONT WILL PASS THIS MORNING...ALLOWING HIGH PRESSURE TO
BUILD IN THROUGH THE REMAINDER OF THE WEEKEND. AS THE HIGH MOVES
SLOWLY OFF THE COAST MONDAY...AN INTENSIFYING LOW PRESSURE SYSTEM
WILL MOVE NORTHEAST AND MERGE WITH A COLD FRONT AS IT PASSES OVER
THE REGION TUESDAY NIGHT. HIGH PRESSURE WILL MOVE EAST ACROSS THE
AREA WEDNESDAY THROUGH THURSDAY FOLLOWED BY A COLD FRONT LATE
FRIDAY.
&&
.NEAR TERM /UNTIL 11 AM THIS MORNING/...
COLD FRONT AT 6AM WAS CLEARING MONTAUK. LINE OF SHRA TRACKING EWD
THRU CNTRL CT AND CLIPPING LI. POPS UPDATED TO BETTER CAPTURE THIS
BAND. RAPID CLEARING UPSTREAM...SO AFT ANY RAIN FALLS SKIES WILL
CLEAR. THE HRRR WAS FOLLOWED FAIRLY CLOSELY FOR POPS THIS MRNG.
&&
.SHORT TERM /11 AM THIS MORNING THROUGH MONDAY NIGHT/...
MIDWEST HIPRES WILL BUILD INTO THE REGION FOR THE REMAINDER OF
THE WEEKEND. SKIES WILL THEREFORE REMAIN MAINLY CLEAR THRU THE
PERIOD. TEMPS A BLEND OF THE MET/MAV. BREEZY NW FLOW TODAY...BUT
LIGHT WINDS ON SUN.
THE HIGH DRIFTS OFFSHORE ON MON...RESULTING IN DEVELOPING RETURN
FLOW. 00Z MODELS SUPPORT THE CURRENT FCST OF DRY. THERE SHOULD BE
SOME INCREASING HIGH AND POTENTIALLY MID CLOUD COVER FROM THE SW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
POTENTIAL FOR A SIGNIFICANT STORM TUESDAY THROUGH TUESDAY NIGHT.
00Z MODELS SHOW NO DEVIATION FROM THE STORMY SOLN. TABLE IS SET
SO NO SIGNIFICANT CHANGES WERE MADE TO THE EXTENDED.
FORECAST MODELS SHOW A SHORT WAVE OVER THE SOUTH CENTRAL U.S.
MOVING NE AND AN AMPLIFYING SHORT WAVE MOVING SE TOWARD THE GREAT
LAKES THAT PHASE TOGETHER PRODUCING A FULL AMPLITUDE TROUGH THAT
BECOMES NEGATIVELY TITLED BY TUESDAY NIGHT.
ALTHOUGH THERE ARE ALWAYS DIFFERENCES IN EXACTLY WHERE THE LOW
LEVEL LOW PRES SYSTEM DEVELOPS ALONG WITH ITS AMPLIFICATION AND
SUBSEQUENT TRACK...THERE ARE GROWING SIGNALS OF AN INTENSIFYING
LOW PRES SYSTEM MOVING TO THE N-NE AND PASSING JUST WEST OF THE
AREA LATE TUESDAY.
POTENTIAL IMPACTS ASSOCIATED WITH THIS SYSTEM WOULD INCLUDE SEVERE
TSTMS WITH ISOLATED TORNADOES...FLASH FLOOD PRODUCING
RAINFALL...STRONG GRADIENT WINDS AND COASTAL FLOODING.
AN OUTLOOK FOR THIS STORM WILL BE ISSUED WITH THIS FCST UPDATE.
STAY TUNED.
FAIR WEATHER WILL RETURN ON WEDNESDAY AS HIGH PRESSURE MOVES
TOWARD THE AREA WHICH IS FORECAST TO CONTINUE ON THURSDAY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT WAS EAST OF THE TERMINALS EARLY THIS MORNING. HIGH
PRESSURE WILL BUILD IN THIS AFTERNOON THROUGH SUNDAY.
GENERALLY VFR CONDITIONS...HOWEVER THERE COULD BE LOCAL MARGINAL VFR
CEILINGS AROUND 2K FT AT THE TERMINALS EAST OF NYC THROUGH 13Z.
WINDS WILL BE NORTH TO NORTHWEST WITH GUSTS AROUND 20 KT UNTIL ABOUT
15Z...THEN WINDS WILL REMAIN STRONG THROUGH THE AFTERNOON. WINDS
DIMINISH FARTHER AFTER 00Z.
OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
.SUNDAY-MONDAY AFTERNOON...VFR.
.MONDAY NIGHT-TUESDAY NIGHT...IFR/MVFR CONDITIONS WITH WIDESPREAD
SHOWERS AHEAD OF AN APPROACHING WARM FRONT FOLLOWED BY A COLD FRONT.
.WEDNESDAY...CLEARING CONDITIONS AS HIGH PRESSURE BUILDS IN BEHIND
THE COLD FRONT.
&&
.MARINE...
A COLD FRONT MOVES ACROSS THE FORECAST WATERS EARLY THIS MORNING
WITH WINDS SHIFTING TO THE NORTH TO NORTHWEST BEHIND THE FRONT. THIS
AFTERNOON THE FRONT WILL MOVE SLOWLY ONCE IT MOVES EAST OF THE
FORECAST WATERS AND WINDS MAY GUST OCCASIONALLY TO 25 KT ON THE
EASTERN OCEAN WATERS WITH SEAS COMING UP TO CLOSE TO 5 FT LATE THIS
AFTERNOON INTO EARLY THIS EVENING. HIGH PRESSURE BUILDS INTO THE
WATERS LATE THIS AFTERNOON INTO SUNDAY AND WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED INTO MONDAY.
MONDAY NIGHT THROUGH TUESDAY NIGHT...THERE IS A POTENTIAL FOR A
WIDESPREAD HEAVY RAINFALL FROM 1 TO 3 INCHES WITH ISOLATED AMOUNTS
OF 4 INCHES LEADING TO MINOR URBAN POOR DRAINAGE FLOODING.
ISOLATED URBAN FLASH FLOODING CANNOT BE RULED OUT. STAY TUNED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JMC/GC
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...JMC/GC
AVIATION...MET
MARINE...MET
HYDROLOGY...JMC/GC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
603 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A COLD FRONT WILL PASS THIS MORNING...ALLOWING HIGH PRESSURE TO
BUILD IN THROUGH THE REMAINDER OF THE WEEKEND. AS THE HIGH MOVES
SLOWLY OFF THE COAST MONDAY...AN INTENSIFYING LOW PRESSURE SYSTEM
WILL MOVE NORTHEAST AND MERGE WITH A COLD FRONT AS IT PASSES OVER
THE REGION TUESDAY NIGHT. HIGH PRESSURE WILL MOVE EAST ACROSS THE
AREA WEDNESDAY THROUGH THURSDAY FOLLOWED BY A COLD FRONT LATE
FRIDAY.
&&
.NEAR TERM /UNTIL 11 AM THIS MORNING/...
COLD FRONT AT 6AM WAS CLEARING MONTAUK. LINE OF SHRA TRACKING EWD
THRU CNTRL CT AND CLIPPING LI. POPS UPDATED TO BETTER CAPTURE THIS
BAND. RAPID CLEARING UPSTREAM...SO AFT ANY RAIN FALLS SKIES WILL
CLEAR. THE HRRR WAS FOLLOWED FAIRLY CLOSELY FOR POPS THIS MRNG.
&&
.SHORT TERM /11 AM THIS MORNING THROUGH MONDAY NIGHT/...
MIDWEST HIPRES WILL BUILD INTO THE REGION FOR THE REMAINDER OF
THE WEEKEND. SKIES WILL THEREFORE REMAIN MAINLY CLEAR THRU THE
PERIOD. TEMPS A BLEND OF THE MET/MAV. BREEZY NW FLOW TODAY...BUT
LIGHT WINDS ON SUN.
THE HIGH DRIFTS OFFSHORE ON MON...RESULTING IN DEVELOPING RETURN
FLOW. 00Z MODELS SUPPORT THE CURRENT FCST OF DRY. THERE SHOULD BE
SOME INCREASING HIGH AND POTENTIALLY MID CLOUD COVER FROM THE SW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
POTENTIAL FOR A SIGNIFICANT STORM TUESDAY THROUGH TUESDAY NIGHT.
00Z MODELS SHOW NO DEVIATION FROM THE STORMY SOLN. TABLE IS SET
SO NO SIGNIFICANT CHANGES WERE MADE TO THE EXTENDED.
FORECAST MODELS SHOW A SHORT WAVE OVER THE SOUTH CENTRAL U.S.
MOVING NE AND AN AMPLIFYING SHORT WAVE MOVING SE TOWARD THE GREAT
LAKES THAT PHASE TOGETHER PRODUCING A FULL AMPLITUDE TROUGH THAT
BECOMES NEGATIVELY TITLED BY TUESDAY NIGHT.
ALTHOUGH THERE ARE ALWAYS DIFFERENCES IN EXACTLY WHERE THE LOW
LEVEL LOW PRES SYSTEM DEVELOPS ALONG WITH ITS AMPLIFICATION AND
SUBSEQUENT TRACK...THERE ARE GROWING SIGNALS OF AN INTENSIFYING
LOW PRES SYSTEM MOVING TO THE N-NE AND PASSING JUST WEST OF THE
AREA LATE TUESDAY.
POTENTIAL IMPACTS ASSOCIATED WITH THIS SYSTEM WOULD INCLUDE SEVERE
TSTMS WITH ISOLATED TORNADOES...FLASH FLOOD PRODUCING
RAINFALL...STRONG GRADIENT WINDS AND COASTAL FLOODING.
AN OUTLOOK FOR THIS STORM WILL BE ISSUED WITH THIS FCST UPDATE.
STAY TUNED.
FAIR WEATHER WILL RETURN ON WEDNESDAY AS HIGH PRESSURE MOVES
TOWARD THE AREA WHICH IS FORECAST TO CONTINUE ON THURSDAY.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT CONTINUES TO MOVE EAST AND AT 08Z WAS THROUGH THE
LOWER HUDSON VALLEY AND NYC. THE FRONT IS EXPECTED TO BE EAST OF THE
REGION BY 12Z TONIGHT.
VFR. S-SW FLOW AT 10 KT OR LESS WILL SHIFT TO THE NW AND BECOME
GUSTY BEHIND THE COLD FRONT.
AREAS OF LIGHT SHOWERS MOVING THROUGH THE LOWER HUDSON VALLY AND
INTO NORTHEASTERN NEW JERSEY CONTINUES TO BE LIGHT AND MAY WEAKEN AS
THE AREA SHIFTS EAST WITH THE BETTER FORCING TO THE NORTH. MVFR
CEILINGS WERE OBSERVED IN SOUTHERN CONNECTICUT BUT ARE NOT EXPECTED
AT THE TERMINALS.
NW WINDS INCREASE WITH GUSTS AROUND 20 KT IN THE MORNING. SOME
UNCERTAINTY WITH HOW STRONG WINDS ARE IN THE LOW LEVELS DURING THE
AFTN...BUT THERE IS THE POTENTIAL FOR OCCASIONAL GUSTS AROUND 20 KT
TO CONTINUE THROUGH THE AFTN AS WELL. DUE TO LOWER CONFIDENCE...HAVE
NOT INCLUDED THIS IN THE TAFS.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.SATURDAY NIGHT-MONDAY AFTERNOON...VFR.
.MONDAY NIGHT-TUESDAY NIGHT...IFR/MVFR CONDITIONS WITH WIDESPREAD
SHOWERS AHEAD OF AN APPROACHING WARM FRONT FOLLOWED BY A COLD FRONT.
.WEDNESDAY...CLEARING CONDITIONS AS HIGH PRESSURE BUILDS IN BEHIND
THE COLD FRONT.
&&
.MARINE...
A COLD FRONT MOVES ACROSS THE FORECAST WATERS EARLY THIS MORNING
WITH WINDS SHIFTING TO THE NORTH TO NORTHWEST BEHIND THE FRONT. THIS
AFTERNOON THE FRONT WILL MOVE SLOWLY ONCE IT MOVES EAST OF THE
FORECAST WATERS AND WINDS MAY GUST OCCASIONALLY TO 25 KT ON THE
EASTERN OCEAN WATERS WITH SEAS COMING UP TO CLOSE TO 5 FT LATE THIS
AFTERNOON INTO EARLY THIS EVENING. HIGH PRESSURE BUILDS INTO THE
WATERS LATE THIS AFTERNOON INTO SUNDAY AND WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED INTO MONDAY.
MONDAY NIGHT THROUGH TUESDAY NIGHT...THERE IS A POTENTIAL FOR A
WIDESPREAD HEAVY RAINFALL FROM 1 TO 3 INCHES WITH ISOLATED AMOUNTS
OF 4 INCHES LEADING TO MINOR URBAN POOR DRAINAGE FLOODING.
ISOLATED URBAN FLASH FLOODING CANNOT BE RULED OUT. STAY TUNED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JMC/GC
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...JMC/GC
AVIATION...MET
MARINE...MET
HYDROLOGY...JMC/GC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
438 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A COLD FRONT WILL PASS THIS MORNING...ALLOWING HIGH PRESSURE TO
BUILD IN THROUGH THE REMAINDER OF THE WEEKEND. AS THE HIGH MOVES
SLOWLY OFF THE COAST MONDAY...AN INTENSIFYING LOW PRESSURE SYSTEM
WILL MOVE NORTHEAST AND MERGE WITH A COLD FRONT AS IT PASSES OVER
THE REGION TUESDAY NIGHT. HIGH PRESSURE WILL MOVE EAST ACROSS THE
AREA WEDNESDAY THROUGH THURSDAY FOLLOWED BY A COLD FRONT LATE
FRIDAY.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
COLD FRONT AT 3AM STRETCHED FROM NEAR KDXR THRU THE CITY. THE SHRA
WERE POST FRONTAL ASSOCIATED WITH THE MID LVL FORCING...AND ONLY
INTO NWRN ORANGE COUNTY. PCPN IS HOLDING TOGETHER...SO FOLLOWED
THE HRRR FOR NEAR TERM LIKELY POPS.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH MONDAY NIGHT/...
SHRA IN ASSOCIATION WITH H7 MOISTURE AXIS WILL EXIT EWD THRU THE
MRNG HOURS. THE HRRR WAS FOLLOWED CLOSELY FOR POPS. BEST DYNAMICS
REMAIN TO THE N...SO LGT TO MDT RAIN RATES CAN BE EXPECTED.
MIDWEST HIPRES WILL THEN BUILD INTO THE REGION FOR THE REMAINDER
OF THE WEEKEND. SKIES WILL THEREFORE REMAIN MAINLY CLEAR THRU THE
PERIOD. TEMPS A BLEND OF THE MET/MAV.
THE HIGH DRIFTS OFFSHORE ON MON...RESULTING IN DEVELOPING RETURN
FLOW. 00Z MODELS SUPPORT THE CURRENT FCST OF DRY. THERE SHOULD BE
SOME INCREASING HIGH AND POTENTIALLY MID CLOUD COVER FROM THE SW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
POTENTIAL FOR A SIGNIFICANT STORM TUESDAY THROUGH TUESDAY NIGHT.
00Z MODELS SHOW NO DEVIATION FROM THE STORMY SOLN. TABLE IS SET
SO NO SIGNIFICANT CHANGES WERE MADE TO THE EXTENDED.
FORECAST MODELS SHOW A SHORT WAVE OVER THE SOUTH CENTRAL U.S.
MOVING NE AND AN AMPLIFYING SHORT WAVE MOVING SE TOWARD THE GREAT
LAKES THAT PHASE TOGETHER PRODUCING A FULL AMPLITUDE TROUGH THAT
BECOMES NEGATIVELY TITLED BY TUESDAY NIGHT.
ALTHOUGH THERE ARE ALWAYS DIFFERENCES IN EXACTLY WHERE THE LOW
LEVEL LOW PRES SYSTEM DEVELOPS ALONG WITH ITS AMPLIFICATION AND
SUBSEQUENT TRACK...THERE ARE GROWING SIGNALS OF AN INTENSIFYING
LOW PRES SYSTEM MOVING TO THE N-NE AND PASSING JUST WEST OF THE
AREA LATE TUESDAY.
POTENTIAL IMPACTS ASSOCIATED WITH THIS SYSTEM WOULD INCLUDE SEVERE
TSTMS WITH ISOLATED TORNADOES...FLASH FLOOD PRODUCING
RAINFALL...STRONG GRADIENT WINDS AND COASTAL FLOODING.
AN OUTLOOK FOR THIS STORM WILL BE ISSUED WITH THIS FCST UPDATE.
STAY TUNED.
FAIR WEATHER WILL RETURN ON WEDNESDAY AS HIGH PRESSURE MOVES
TOWARD THE AREA WHICH IS FORECAST TO CONTINUE ON THURSDAY.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT CONTINUES TO MOVE EAST AND AT 08Z WAS THROUGH THE
LOWER HUDSON VALLEY AND NYC. THE FRONT IS EXPECTED TO BE EAST OF THE
REGION BY 12Z TONIGHT.
VFR. S-SW FLOW AT 10 KT OR LESS WILL SHIFT TO THE NW AND BECOME
GUSTY BEHIND THE COLD FRONT.
AREAS OF LIGHT SHOWERS MOVING THROUGH THE LOWER HUDSON VALLY AND
INTO NORTHEASTERN NEW JERSEY CONTINUES TO BE LIGHT AND MAY WEAKEN AS
THE AREA SHIFTS EAST WITH THE BETTER FORCING TO THE NORTH. MVFR
CEILINGS WERE OBSERVED IN SOUTHERN CONNECTICUT BUT ARE NOT EXPECTED
AT THE TERMINALS.
NW WINDS INCREASE WITH GUSTS AROUND 20 KT IN THE MORNING. SOME
UNCERTAINTY WITH HOW STRONG WINDS ARE IN THE LOW LEVELS DURING THE
AFTN...BUT THERE IS THE POTENTIAL FOR OCCASIONAL GUSTS AROUND 20 KT
TO CONTINUE THROUGH THE AFTN AS WELL. DUE TO LOWER CONFIDENCE...HAVE
NOT INCLUDED THIS IN THE TAFS.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.SATURDAY NIGHT-MONDAY AFTERNOON...VFR.
.MONDAY NIGHT-TUESDAY NIGHT...IFR/MVFR CONDITIONS WITH WIDESPREAD
SHOWERS AHEAD OF AN APPROACHING WARM FRONT FOLLOWED BY A COLD FRONT.
.WEDNESDAY...CLEARING CONDITIONS AS HIGH PRESSURE BUILDS IN BEHIND
THE COLD FRONT.
&&
.MARINE...
A COLD FRONT MOVES ACROSS THE FORECAST WATERS EARLY THIS MORNING
WITH WINDS SHIFTING TO THE NORTH TO NORTHWEST BEHIND THE FRONT. THIS
AFTERNOON THE FRONT WILL MOVE SLOWLY ONCE IT MOVES EAST OF THE
FORECAST WATERS AND WINDS MAY GUST OCCASIONALLY TO 25 KT ON THE
EASTERN OCEAN WATERS WITH SEAS COMING UP TO CLOSE TO 5 FT LATE THIS
AFTERNOON INTO EARLY THIS EVENING. HIGH PRESSURE BUILDS INTO THE
WATERS LATE THIS AFTERNOON INTO SUNDAY AND WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED INTO MONDAY.
MONDAY NIGHT THROUGH TUESDAY NIGHT...THERE IS A POTENTIAL FOR A
WIDESPREAD HEAVY RAINFALL FROM 1 TO 3 INCHES WITH ISOLATED AMOUNTS
OF 4 INCHES LEADING TO MINOR URBAN POOR DRAINAGE FLOODING.
ISOLATED URBAN FLASH FLOODING CANNOT BE RULED OUT. STAY TUNED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JMC/GC
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...JMC/GC
AVIATION...MET
MARINE...MET
HYDROLOGY...JMC/GC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
327 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A COLD FRONT WILL PASS THIS MORNING...ALLOWING HIGH PRESSURE TO
BUILD IN THROUGH THE REMAINDER OF THE WEEKEND. AS THE HIGH MOVES
SLOWLY OFF THE COAST MONDAY...AN INTENSIFYING LOW PRESSURE SYSTEM
WILL MOVE NORTHEAST AND MERGE WITH A COLD FRONT AS IT PASSES OVER
THE REGION TUESDAY NIGHT. HIGH PRESSURE WILL MOVE EAST ACROSS THE
AREA WEDNESDAY THROUGH THURSDAY FOLLOWED BY A COLD FRONT LATE
FRIDAY.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
COLD FRONT AT 3AM STRETCHED FROM NEAR KDXR THRU THE CITY. THE SHRA
WERE POST FRONTAL ASSOCIATED WITH THE MID LVL FORCING...AND ONLY
INTO NWRN ORANGE COUNTY. PCPN IS HOLDING TOGETHER...SO FOLLOWED
THE HRRR FOR NEAR TERM LIKELY POPS.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH MONDAY NIGHT/...
SHRA IN ASSOCIATION WITH H7 MOISTURE AXIS WILL EXIT EWD THRU THE
MRNG HOURS. THE HRRR WAS FOLLOWED CLOSELY FOR POPS. BEST DYNAMICS
REMAIN TO THE N...SO LGT TO MDT RAIN RATES CAN BE EXPECTED.
MIDWEST HIPRES WILL THEN BUILD INTO THE REGION FOR THE REMAINDER
OF THE WEEKEND. SKIES WILL THEREFORE REMAIN MAINLY CLEAR THRU THE
PERIOD. TEMPS A BLEND OF THE MET/MAV.
THE HIGH DRIFTS OFFSHORE ON MON...RESULTING IN DEVELOPING RETURN
FLOW. 00Z MODELS SUPPORT THE CURRENT FCST OF DRY. THERE SHOULD BE
SOME INCREASING HIGH AND POTENTIALLY MID CLOUD COVER FROM THE SW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
POTENTIAL FOR A SIGNIFICANT STORM TUESDAY THROUGH TUESDAY NIGHT.
00Z MODELS SHOW NO DEVIATION FROM THE STORMY SOLN. TABLE IS SET
SO NO SIGNIFICANT CHANGES WERE MADE TO THE EXTENDED.
FORECAST MODELS SHOW A SHORT WAVE OVER THE SOUTH CENTRAL U.S.
MOVING NE AND AN AMPLIFYING SHORT WAVE MOVING SE TOWARD THE GREAT
LAKES THAT PHASE TOGETHER PRODUCING A FULL AMPLITUDE TROUGH THAT
BECOMES NEGATIVELY TITLED BY TUESDAY NIGHT.
ALTHOUGH THERE ARE ALWAYS DIFFERENCES IN EXACTLY WHERE THE LOW
LEVEL LOW PRES SYSTEM DEVELOPS ALONG WITH ITS AMPLIFICATION AND
SUBSEQUENT TRACK...THERE ARE GROWING SIGNALS OF AN INTENSIFYING
LOW PRES SYSTEM MOVING TO THE N-NE AND PASSING JUST WEST OF THE
AREA LATE TUESDAY.
POTENTIAL IMPACTS ASSOCIATED WITH THIS SYSTEM WOULD INCLUDE SEVERE
TSTMS WITH ISOLATED TORNADOES...FLASH FLOOD PRODUCING
RAINFALL...STRONG GRADIENT WINDS AND COASTAL FLOODING.
AN OUTLOOK FOR THIS STORM WILL BE ISSUED WITH THIS FCST UPDATE.
STAY TUNED.
FAIR WEATHER WILL RETURN ON WEDNESDAY AS HIGH PRESSURE MOVES
TOWARD THE AREA WHICH IS FORECAST TO CONTINUE ON THURSDAY.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT APPROACHING FROM THE WEST WILL PASS THROUGH
THE TERMINALS BETWEEN 06Z AND 12Z TONIGHT.
VFR. S-SW FLOW AT 10 KT OR LESS WILL SHIFT TO THE W AND
EVENTUALLY NW BEHIND THE COLD FRONT.
MODELS CONTINUE TO INDICATE THAT THE SHOWERS OVER EASTERN PA WILL
WEAKEN AS THEY MOVE EAST WITH THE BETTER FORCING LIFTING TO THE N
OF THE AREA. HAVE KEPT TEMPO AT KSWF BETWEEN 07Z AND 09Z WHERE A
LIGHT SHOWER MAY BE ABLE TO HOLD TOGETHER. OTHERWISE...WET RUNWAYS
NOT EXPECTED AT REMAINDER OF TERMINALS.
NW WINDS INCREASE WITH GUSTS AROUND 20 KT IN THE MORNING. SOME
UNCERTAINTY WITH HOW STRONG WINDS ARE IN THE LOW LEVELS DURING THE
AFTN...BUT THERE IS THE POTENTIAL FOR OCCASIONAL GUSTS AROUND 20
KT TO CONTINUE THROUGH THE AFTN AS WELL. DUE TO LOWER
CONFIDENCE...HAVE NOT INCLUDED THIS IN THE TAFS.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.SATURDAY NIGHT-MONDAY AFTERNOON...VFR.
.MONDAY NIGHT-TUESDAY NIGHT...IFR/MVFR CONDITIONS WITH WIDESPREAD
SHOWERS AHEAD OF AN APPROACHING WARM FRONT FOLLOWED BY A COLD FRONT.
.WEDNESDAY...CLEARING CONDITIONS AS HIGH PRESSURE BUILDS IN BEHIND
THE COLD FRONT.
&&
.MARINE...
A COLD FRONT MOVES ACROSS THE FORECAST WATERS EARLY THIS MORNING
WITH WINDS SHIFTING TO THE NORTH TO NORTHWEST BEHIND THE FRONT. THIS
AFTERNOON THE FRONT WILL MOVE SLOWLY ONCE IT MOVES EAST OF THE
FORECAST WATERS AND WINDS MAY GUST OCCASIONALLY TO 25 KT ON THE
EASTERN OCEAN WATERS WITH SEAS COMING UP TO CLOSE TO 5 FT LATE THIS
AFTERNOON INTO EARLY THIS EVENING. HIGH PRESSURE BUILDS INTO THE
WATERS LATE THIS AFTERNOON INTO SUNDAY AND WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED INTO MONDAY.
MONDAY NIGHT THROUGH TUESDAY NIGHT...THERE IS A POTENTIAL FOR A
WIDESPREAD HEAVY RAINFALL FROM 1 TO 3 INCHES WITH ISOLATED AMOUNTS
OF 4 INCHES LEADING TO MINOR URBAN POOR DRAINAGE FLOODING.
ISOLATED URBAN FLASH FLOODING CANNOT BE RULED OUT. STAY TUNED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JMC/GC
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...JMC/GC
AVIATION...MET
MARINE...MET
HYDROLOGY...JMC/GC
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
950 PM EDT SUN SEP 16 2012
.DISCUSSION...
LATEST RAP ANALYSIS SHOWS A NEARLY STATIONARY H100-H70 ANTICYCLONE
CENTERED JUST OFF THE GA COAST GENERATING A DEEP AND STEADY E/SE
FLOW ACRS THE FL PENINSULA. THESE WINDS WILL TAP A MOIST AIRMASS
OVER THE BAHAMAS...00Z KTBW/KMFL RAOBS CONFIRM THIS WITH PWAT VALUES
ABV 2.1". THE E/SE FLOW WILL ALLOW ISOLD SHRAS TO DVLP IN THE
CONVERGENT EDDIES DOWNWIND OF THE NRN BAHAMAS THAT WILL THEN PUSH
TOWARD THE TREASURE AND SRN SPACE COAST.
THE USAF 915HZ PROFILER SHOWS THE ONSHORE FLOW HAS WEAKENED SOMEWHAT
OVER THE PAST SVRL HRS WHILE LATEST RADAR TRENDS SHOW PRECIP HAS
DISSIPATED OVER THE INTERIOR. RAP ANALYSIS SHOWS LITTLE IN THE WAY
OF MID/UPR LVL DYNAMIC SUPPORT OUTSIDE OF WEAK ISENTROPIC LIFT OVER
THE S HALF OF THE CWA.
WILL KEEP ISOLATED SHOWERS OVER THE COASTAL COUNTIES THRU THE
OVERNIGHT HOURS AS NOCTURNAL CONVERGENCE APPROACHES ITS MAX IN THE
ONSHORE FLOW REGIME. ALSO WILL KEEP TSRAS IN THE FCST ACRS THE SRN
CSTL COUNTIES TO ACCOUNT FOR WEAK IMPULSES THAT MAY PINCH OFF OF A
VORT MAX BTWN THE KEYS AND ANDROS ISLAND. WILL REMOVE INTERIOR POPS
AS ADDITIONAL SHRAS APPEAR UNLIKELY...ANY THAT MIGHT FORM WOULD HAVE
NEGLIGIBLE IMPACT. WILL INCREASE CLOUD COVER OVR THE SRN HALF OF THE
CWA AS WELL TO ACCOUNT FOR LARGE AMNTS OF UPR LVL CONVECTIVE DEBRIS
CLDS.
&&
.AVIATION...
THRU 17/13Z...PREVAILING VFR ALL SITES...S OF KVRB BRIEF PDS OF MVFR
CIGS/VSBYS IN ISOLD CSTL SHRAS. BTWN 17/13Z-17/17Z...SFC WNDS BCMG
SE AOB 12KTS...ISOLD MVFR SHRAS. AFT 17/17Z...SE SFC WNDS 12-15KTS
WITH OCNL G20-22KTS E OF KMLB-KOBE...G18-20KTS W OF KMLB-KOBE...SCT
MVFR SHRAS/ISOLD IFR TSRAS ALL SITES MVG N/NW 10-15KTS.
&&
.MARINE...
LATEST BUOY OBS SHOW THE SWELL FROM DISTANT T.C. NADINE IS PAST PEAK
WITH BUOY010 HOVERING ARND 5FT...BUOY009/012 AROUND 4FT...AND
NEARSHORE SCRIPPS BUOYS BTWN 3-4FT...ALL CARRYING DOMINANT PDS BTWN
12-14SEC...ALL WITH E/SE WINDS ARND 10KTS. A FEW SHOWERS THROUGH THE
EVENING AND A FEW TSRA POSSIBLE SOUTHERN LEGS...ESP AFTER MIDNIGHT
THROUGH MONDAY MORNING. AFTN FCST LOOKS GOOD WITH 6FT SEAS OVER THE
GULF STREAM SUBSIDING TO 5FT IN THE PREDAWN HRS...ALL OTHER AREAS
AOB 5FT. GIVEN THE DIMINISHING WINDS...WILL LOWER THE CAUTIONARY
STATEMENT WITH THE EVNG PACKAGE...NO OTHER CHANGES NECESSARY.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....CRISTALDI
AREA FORECAST DISCUSSION...UPDATED
NWS MELBOURNE FL
1138 AM EDT SAT SEP 15 2012
.DISCUSSION...
LARGE CONTINENTAL RIDGE BLANKETING MUCH OF THE ERN SEABOARD WILL
MAINTAIN A DEEP E/NERLY FLOW ACRS CENTRAL FL THRU THE DAY. WINDS
WILL NOT BE QUITE AS STRONG AS FRI AS THE WEAK FRONTAL BNDRY OVER
THE SE CONUS HAS LARGELY BEEN BRIDGED BY THE RIDGE AND WILL NOT PLAY
A DIRECT ROLE FOR CENTRAL FL WX THIS AFTN/EVNG.
MORNING SOUNDINGS SHOW MOISTURE INCREASING FROM N TO S ACRS THE
PENINSULA...PWAT VALUES 1.7" AT KJAX...1.9"-2.0" AT KXMR/KTBW...AND
2.2" AT KMFL. MID LVL LAPSE RATES REMAIN WEAK...BTWN 5.0-5.5C/KM...
THOUGH H50 TEMPS HAVE COOLED SLIGHTLY TO BTWN -7.5C AND -8.0C.
LATEST RAP ANALYSIS SHOWS SOME DRIER AIR JUST OFF THE E FL COAST
WITH H100-H70 MEAN RH BLO 70PCT...H85-H50 MEAN RH BLO 60PCT.
THE LIGHTER WINDS WILL ALLOW THE EAST COAST SEA BREEZE TO FORM WITH
BETTER DEFINITION THAN IN RECENT DAYS. THIS IN TURN WILL ALLOW A FEW
DIURNAL SHRAS TO DVLP INTO TSRAS...WHILE THE WEAKER STEERING FLOW
WILL RESULT IN SLOWER STORM MOTION AND LOCAL HEAVY RAIN. THE FOCUS
FOR SCT SHRAS/ISOLD TSRAS WILL SHIFT TO THE WRN PENINSULA LATE IN
THE DAY. DEEP ONSHORE FLOW WILL KEEP MAX TEMPS IN THE M/U80S COAST
AND U80S/L90S INLAND.
THE GFS SHOWS THE DRIER AIR TRYING TO PUSH INTO THE AREA...WHICH
SHOULD WORK TO LOWER POPS THIS AFTN. WILL LOWER POPS TO 20PCT FOR
COASTAL VOLUSIA AND NRN BREVARD....REMAINDER OF THE FCST LOOKS GOOD.
&&
.AVIATION...
THRU 16/00Z...E/NE SFC WND 8-13KTS...PREVAILING VFR ALL SITES...
BRIEF PDS OF IFR CIGS/VSBYS IN SCT SHRAS/ISOLD TSRA WITH OCNL SFC
WND G22-25KTS. AFT 16/00Z...SFC WND E/NE AOB 5KTS...PREVAILING VFR
ALL SITES...ISOLD IFR CIGS/VSBYS COASTAL SITES.
&&
.MARINE...
LARGE CONTINENTAL RIDGE AXIS CENTERED OVER THE MIDWEST WILL GENERATE
A GENTLE TO MODERATE E/NE SFC/BNDRY LYR BREEZE THRU SUNSET...
LINGERING SWELL WILL KEEP SEAS 3-4FT AREAWIDE. ISOLD SHRAS/TSRAS MVG
ONSHORE. VERY LONG PD SWELLS FROM DISTANT T.C. NADINE WILL BEGIN TO
PROPAGATE INTO THE LCL ATLC THIS AFTN BUT INITIALLY SHOULD GO
UNNOTICED. SWELLS WILL BUILD TONIGHT AND BOOST SEAS TO 5-6FT
OVERNIGHT. THIS WILL GENERATE HAZARDOUS BOATING CONDITIONS NEAR
INLETS BY DAYBREAK SUNDAY.
NOTE TO USERS: NOAA BUOY 41009 HAS BEEN RETURNED TO SERVICE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....GLITTO
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1015 AM EDT SAT SEP 15 2012
.DISCUSSION...
LARGE CONTINENTAL RIDGE BLANKETING MUCH OF THE ERN SEABOARD WILL
MAINTAIN A DEEP E/NERLY FLOW ACRS CENTRAL FL THRU THE DAY. WINDS
WILL NOT BE QUITE AS STRONG AS FRI AS THE WEAK FRONTAL BNDRY OVER
THE SE CONUS HAS LARGELY BEEN BRIDGED BY THE RIDGE AND WILL NOT PLAY
A DIRECT ROLE FOR CENTRAL FL WX THIS AFTN/EVNG.
MORNING SOUNDINGS SHOW MOISTURE INCREASING FROM N TO S ACRS THE
PENINSULA...PWAT VALUES 1.7" AT KJAX...1.9"-2.0" AT KXMR/KTBW...AND
2.2" AT KMFL. MID LVL LAPSE RATES REMAIN WEAK...BTWN 5.0-5.5C/KM...
THOUGH H50 TEMPS HAVE COOLED SLIGHTLY TO BTWN -7.5C AND -8.0C.
LATEST RAP ANALYSIS SHOWS SOME DRIER AIR JUST OFF THE E FL COAST
WITH H100-H70 MEAN RH BLO 70PCT...H85-H50 MEAN RH BLO 60PCT.
THE LIGHTER WINDS WILL ALLOW THE EAST COAST SEA BREEZE TO FORM WITH
BETTER DEFINITION THAN IN RECENT DAYS. THIS IN TURN WILL ALLOW A FEW
DIURNAL SHRAS TO DVLP INTO TSRAS...WHILE THE WEAKER STEERING FLOW
WILL RESULT IN SLOWER STORM MOTION AND LOCAL HEAVY RAIN. THE FOCUS
FOR SCT SHRAS/ISOLD TSRAS WILL SHIFT TO THE WRN PENINSULA LATE IN
THE DAY. DEEP ONSHORE FLOW WILL KEEP MAX TEMPS IN THE M/U80S COAST
AND U80S/L90S INLAND.
THE GFS SHOWS THE DRIER AIR TRYING TO PUSH INTO THE AREA...WHICH
SHOULD WORK TO LOWER POPS THIS AFTN. WILL LOWER POPS TO 20PCT FOR
COASTAL VOLUSIA AND NRN BREVARD....REMAINDER OF THE FCST LOOKS GOOD.
NOTE TO USERS: THE SOUTHERN REGION SERVER IS CURRENTLY OTS. WITH
THIS OUTAGE...ALL SOUTHERN REGION WEBPAGES ARE UNAVAILABLE.
TECHNICIANS ARE WORKING ON THE PROBLEM...NO RTS ETA AT THIS TIME.
&&
.AVIATION...
THRU 16/00Z...E/NE SFC WND 8-13KTS...PREVAILING VFR ALL SITES...
BRIEF PDS OF IFR CIGS/VSBYS IN SCT SHRAS/ISOLD TSRA WITH OCNL SFC
WND G22-25KTS. AFT 16/00Z...SFC WND E/NE AOB 5KTS...PREVAILING VFR
ALL SITES...ISOLD IFR CIGS/VSBYS COASTAL SITES.
&&
.MARINE...
LARGE CONTINENTAL RIDGE AXIS CENTERED OVER THE MIDWEST WILL GENERATE
A GENTLE TO MODERATE E/NE SFC/BNDRY LYR BREEZE THRU SUNSET...
LINGERING SWELL WILL KEEP SEAS 3-4FT AREAWIDE. ISOLD SHRAS/TSRAS MVG
ONSHORE. VERY LONG PD SWELLS FROM DISTANT T.C. NADINE WILL BEGIN TO
PROPAGATE INTO THE LCL ATLC THIS AFTN BUT INITIALLY SHOULD GO
UNNOTICED. SWELLS WILL BUILD TONIGHT AND BOOST SEAS TO 5-6FT
OVERNIGHT. THIS WILL GENERATE HAZARDOUS BOATING CONDITIONS NEAR
INLETS BY DAYBREAK SUNDAY.
NOTE TO USERS: NOAA BUOY 41009 HAS BEEN RETURNED TO SERVICE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....GLITTO
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
221 PM CDT SAT SEP 15 2012
...UPDATED LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 210 PM CDT SAT SEP 15 2012
IN THE HIGHER LEVELS OF THE ATMOSPHERE, THERE WAS A LIGHT 250MB JET
FROM CENTRAL OLD MEXICO NORTHEAST THROUGH TEXAS AND OKLAHOMA TO THE
EAST COAST OVER COASTAL NORTH CAROLINA. THE AVERAGE SPEED IN THIS
JET WAS 60 KNOTS, WITH A SMALL PEAK JETLET AROUND 70 KNOTS DOWN IN
THE WEST TEXAS PANHANDLE. IN THE NORTHEASTERN PART OF THE U.S.,
THERE WAS TROUGH WITH 90 KNOTS OF NORTHWEST WINDS ON THE WEST SIDE
OF THE TROUGH, OVER THE NORTHEASTERN GREAT LAKES, THEN CURVING TO A
90 KNOT SOUTHERLY JET OVER EASTERN QUEBEC, CANADA. THE 500MB CHART
SHOWED HIGH PRESSURE CENTERED OVER WESTERN UTAH STRETCHING EAST
THROUGH KANSAS, WITH AN UPPER LOW OVER QUEBEC AND ANOTHER OVER THE
GULF OF MEXICO. THE 700MB PATTERN WAS SIMILAR TO THE 500MB LEVEL,
WITH A NORTHEAST WIND AT DDC OF 05 KNOTS AND A 700MB TEMP OF +05.
THE 850MB ANALYSIS SHOWED A WEALTH OF MOISTURE MOVING NORTHEASTWARD
FROM THE TEXAS GULF COAST TO CENTRAL AND EASTERN KANSAS. A WARM
FRONT WAS TO OUR NORTH, FROM SOUTHERN SASKATCHEWAN TO THE EASTERN
DAKOTAS TO SOUTH CENTRAL NEBRASKA. A COLD FRONT WAS EVIDENT FROM AN
850MB LOW PRESSURE CENTER OVER CENTRAL OKLAHOMA SOUTHWESTWARD TO
WEST TEXAS AND THEN WEST TO A LOW OVER WESTERN MEXICO.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 210 PM CDT SAT SEP 15 2012
FOR TONIGHT, HIGH PRESSURE OVERHEAD WILL ALLOW CLEAR OR CLEARING
SKIES, LIGHT SOUTHEAST WINDS IN OUR CENTRAL AND EAST, BUT A TROUGH
IN COLORADO SHOULD TURN WINDS LIGHT SOUTHWEST IN OUR WESTERN
COUNTIES. ALTHOUGH ONLY 5 TO 10 MPH SOUTHWEST WINDS WILL BE OVER
OUR WESTERN COUNTIES, THINK THE UPSLOPE FLOW AFFECT WILL HELP
TEMPERATURES FROM FALLING AS PREVIOUSLY FORECAST. I RAISED MINIMUM
TEMPERATURES IN OUR CENTRAL AND WEST, WHICH NOW FIT BETTER WITH OUR
ISC NEIGHBORS. REVIEWED LAST NIGHT LOWS, WITH GCK AND HYS BOTTOMING
OUT AT 41F, AND THINK THEY SHOULD BE NEAR THAT LEVEL IN THE WEST
TONIGHT. ALL MODEL GUIDANCE IS EVEN HIGHER, IN THE MID 40S OUT
WEST, BUT DID NOT WANT TO SEE-SAW BACK AND FORTH TOO MUCH. IN THE
NEARER TERM, THE NAM AND HRRR MODELS BOTH PRODUCED A LITTLE LIGHT
RAIN IN MY EXTREME SOUTHEAST BY 19Z TODAY. SINCE THIS HAS NOT
MATERIALIZED, DECIDED TO LEAVE POPS OUT OF OUR SOUTHEAST COUNTIES
SUCH AS COMANCHE AND BARBER.
SUNDAY WILL SEE THE SURFACE TROUGH IN OUR WESTERN COUNTIES, PERHAPS
AS FAR EAST AT KEARNY, GRANT AND STEVENS COUNTIES. WINDS WILL SHIFT
SOUTH AND BY AFTERNOON INCREASE INTO THE 12 TO 15 MPH RANGE, GUSTING
TO NEAR 20 MPH. THIS SOUTH WIND WILL AID IN TRANSPORTING WARMER AIR
INTO SOUTHWESTERN KANSAS, ALLOWING MAXIMUM TEMPERATURES TO WARM
APPROXIMATELY 10F DEGREES MORE THAN TODAY. SUNDAY`S HIGHS SHOULD
RANGE FROM 84F IN HAYS AND DODGE CITY TO 89F IN SYRACUSE. HIGH
PRESSURE ALOFT OVER THE PLAINS WILL STILL KEEP A LOT OF SUNSHINE
OVERHEAD, WHICH WILL ALSO AID IN WARMING UP THE SURFACE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 218 PM CDT SAT SEP 15 2012
AN UPPER LEVEL TROUGH WILL EXIT CANADA AND MOVE SOUTHEAST ACROSS THE
NORTHERN PLAINS SUNDAY NIGHT AND MONDAY. AS THIS SYSTEM CROSSES THE
NORTHERN PLAINS A COLD FRONT WILL MOVE ACROSS WESTERN KANSAS.
PRECIPITATION CHANCES WITH THIS COLD FRONT AT THIS TIME STILL
APPEARS SMALL. IF PRECIPITATION DOES OCCUR IT WILL BE ON MONDAY AS
THE UPPER TROUGH CROSSES PORTIONS OF NORTH CENTRAL KANSAS. ANOTHER
AREA WHERE A FEW SHOWERS OR EVEN A THUNDERSTORM MAY DEVELOP WILL BE
IN FAR SOUTHWEST KANSAS NEAR THE LEFT EXIT REGION OF AN UPPER LEVEL
JET. GIVEN THE EXPECTED CLOUD COVER AND THE COOLING THAT IS FORECAST
BEHIND THIS FRONT IN THE 925-850MB LEVEL WILL TREND HIGHS DOWN A
COUPLE OF DEGREES AND FAVOR THE COOLEST MODEL GUIDANCE. HIGHS MONDAY
MAY STRUGGLE TO REACH THE UPPER 60S ACROSS PORTIONS OF WESTERN AND
NORTH CENTRAL KANSAS. GUSTY NORTH WINDS WILL DEVELOP BEHIND THIS
FRONT EARLY MONDAY. NAM MEAN MIXED LAYER WINDS SUGGESTING SUSTAINED
WIND SPEEDS OF 30 TO 35 MPH AT 15Z AND 18Z MONDAY. GFS WAS A LITTLE
WEAKER WITH THESE MIXED LAYER WINDS BUT GIVEN THE MAGNITUDE OF THE
COLD AIR ADVECTION DEVELOPING EARLY MONDAY WILL LEAN TOWARDS THE
STRONGER NAM WINDS AT THIS TIME.
BY MONDAY NIGHT THE UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA AS
AN AREA OF HIGH PRESSURE AT THE SURFACE BEGINS TO SETTLE INTO
KANSAS. SKIES MAY BE CLEAR EARLY BUT BASED ON THE GFS AND ECMWF SOME
700MB MOISTURE AND WARM AIR ADVECTION IMPROVES DURING THE OVERNIGHT
HOURS ACROSS WESTERN KANSAS. GIVEN LIGHT WINDS AND DEWPOINT IN THE
UPPER 30S TO LOWER 40S WILL FAVOR THE COOLER GUIDANCE FOR OVERNIGHT
TEMPERATURES BUT AM RELUCTANT TO GO MUCH LOWER THAN THE MID 40S
GIVEN THE POTENTIAL FOR SOME CLOUD COVER TOWARDS DAYBREAK.
ON TUESDAY A TROUGH OF LOW PRESSURE A THE SURFACE WILL DEVELOP ALONG
THE LEE OF THE ROCKIES AS A NORTHWEST FLOW PERSISTS. 850MB
TEMPERATURE TRENDS TUESDAY AND WEDNESDAY CONTINUES TO SUPPORT HIGHS
REBOUNDING BACK INTO THE 80S. THIS WARM UP HOWEVER WILL BE SHORT
LIVED AS ANOTHER COLD FRONT IS FORECAST TO MOVE SOUTH ACROSS THE
CENTRAL PLAINS WEDNESDAY NIGHT OR EARLY THURSDAY. NOT ONLY WILL THIS
FRONT BRING COOLER TEMPERATURES BACK TO WESTERN KANSAS BUT THERE MAY
ALSO BE A SLIGHT CHANCE FOR THUNDERSTORMS AS WELL AS ANOTHER UPPER
LEVEL TROUGH CROSSES THE NORTHERN PLAINS. AT THIS TIME MODELS APPEAR
TO BE STRUGGLING WITH THE TRACK AND STRENGTH OF THIS NEXT UPPER
LEVEL SYSTEM. CONFIDENCE IS NOT HIGH ON WHICH MAY BE MORE CORRECT SO
WILL STAY CLOSE TO CONSENSUS FROM THE CREXTENDFCST_INT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1149 AM CDT SAT SEP 15 2012
SURFACE HIGH PRESSURE OVER KANSAS WILL KEEP VFR CONDITIONS
PREVAILING THROUGH THE 24 HOUR TAF PERIOD. CLEAR SKIES WILL
DOMINATE THE TAF SITES, BUT JUST EAST OF THE SITES NEAR MEDICINE
LODGE (P28) AND PRATT (PTT) MVFR CIGS AROUND BKN-OVC025-030 WILL
LINGER THIS AFTERNOON IN ISENTROPIC LIFT FROM OKLAHOMA. LIGHT AND
VARIABLE WINDS EARLY THIS AFTERNOON WILL SHIFT SOUTHEAST AT UNDER
10 KNOTS BY 20Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 53 84 52 72 / 0 0 10 10
GCK 51 87 51 71 / 0 0 10 10
EHA 51 87 52 71 / 0 0 10 10
LBL 50 86 52 73 / 0 0 0 0
HYS 53 85 55 70 / 0 0 10 20
P28 57 85 58 76 / 0 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURKE
SHORT TERM...BURKE
LONG TERM...BURGERT
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
214 PM CDT SAT SEP 15 2012
...UPDATED FOR THE SYNOPSIS AND SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 210 PM CDT SAT SEP 15 2012
IN THE HIGHER LEVELS OF THE ATMOSPHERE, THERE WAS A LIGHT 250MB JET
FROM CENTRAL OLD MEXICO NORTHEAST THROUGH TEXAS AND OKLAHOMA TO THE
EAST COAST OVER COASTAL NORTH CAROLINA. THE AVERAGE SPEED IN THIS
JET WAS 60 KNOTS, WITH A SMALL PEAK JETLET AROUND 70 KNOTS DOWN IN
THE WEST TEXAS PANHANDLE. IN THE NORTHEASTERN PART OF THE U.S.,
THERE WAS TROUGH WITH 90 KNOTS OF NORTHWEST WINDS ON THE WEST SIDE
OF THE TROUGH, OVER THE NORTHEASTERN GREAT LAKES, THEN CURVING TO A
90 KNOT SOUTHERLY JET OVER EASTERN QUEBEC, CANADA. THE 500MB CHART
SHOWED HIGH PRESSURE CENTERED OVER WESTERN UTAH STRETCHING EAST
THROUGH KANSAS, WITH AN UPPER LOW OVER QUEBEC AND ANOTHER OVER THE
GULF OF MEXICO. THE 700MB PATTERN WAS SIMILAR TO THE 500MB LEVEL,
WITH A NORTHEAST WIND AT DDC OF 05 KNOTS AND A 700MB TEMP OF +05.
THE 850MB ANALYSIS SHOWED A WEALTH OF MOISTURE MOVING NORTHEASTWARD
FROM THE TEXAS GULF COAST TO CENTRAL AND EASTERN KANSAS. A WARM
FRONT WAS TO OUR NORTH, FROM SOUTHERN SASKATCHEWAN TO THE EASTERN
DAKOTAS TO SOUTH CENTRAL NEBRASKA. A COLD FRONT WAS EVIDENT FROM AN
850MB LOW PRESSURE CENTER OVER CENTRAL OKLAHOMA SOUTHWESTWARD TO
WEST TEXAS AND THEN WEST TO A LOW OVER WESTERN MEXICO.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 210 PM CDT SAT SEP 15 2012
FOR TONIGHT, HIGH PRESSURE OVERHEAD WILL ALLOW CLEAR OR CLEARING
SKIES, LIGHT SOUTHEAST WINDS IN OUR CENTRAL AND EAST, BUT A TROUGH
IN COLORADO SHOULD TURN WINDS LIGHT SOUTHWEST IN OUR WESTERN
COUNTIES. ALTHOUGH ONLY 5 TO 10 MPH SOUTHWEST WINDS WILL BE OVER
OUR WESTERN COUNTIES, THINK THE UPSLOPE FLOW AFFECT WILL HELP
TEMPERATURES FROM FALLING AS PREVIOUSLY FORECAST. I RAISED MINIMUM
TEMPERATURES IN OUR CENTRAL AND WEST, WHICH NOW FIT BETTER WITH OUR
ISC NEIGHBORS. REVIEWED LAST NIGHT LOWS, WITH GCK AND HYS BOTTOMING
OUT AT 41F, AND THINK THEY SHOULD BE NEAR THAT LEVEL IN THE WEST
TONIGHT. ALL MODEL GUIDANCE IS EVEN HIGHER, IN THE MID 40S OUT
WEST, BUT DID NOT WANT TO SEE-SAW BACK AND FORTH TOO MUCH. IN THE
NEARER TERM, THE NAM AND HRRR MODELS BOTH PRODUCED A LITTLE LIGHT
RAIN IN MY EXTREME SOUTHEAST BY 19Z TODAY. SINCE THIS HAS NOT
MATERIALIZED, DECIDED TO LEAVE POPS OUT OF OUR SOUTHEAST COUNTIES
SUCH AS COMANCHE AND BARBER.
SUNDAY WILL SEE THE SURFACE TROUGH IN OUR WESTERN COUNTIES, PERHAPS
AS FAR EAST AT KEARNY, GRANT AND STEVENS COUNTIES. WINDS WILL SHIFT
SOUTH AND BY AFTERNOON INCREASE INTO THE 12 TO 15 MPH RANGE, GUSTING
TO NEAR 20 MPH. THIS SOUTH WIND WILL AID IN TRANSPORTING WARMER AIR
INTO SOUTHWESTERN KANSAS, ALLOWING MAXIMUM TEMPERATURES TO WARM
APPROXIMATELY 10F DEGREES MORE THAN TODAY. SUNDAY`S HIGHS SHOULD
RANGE FROM 84F IN HAYS AND DODGE CITY TO 89F IN SYRACUSE. HIGH
PRESSURE ALOFT OVER THE PLAINS WILL STILL KEEP A LOT OF SUNSHINE
OVERHEAD, WHICH WILL ALSO AID IN WARMING UP THE SURFACE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 326 AM CDT SAT SEP 15 2012
FOG WILL PROBABLY NOT LAST LONG ON SUNDAY MORNING. WINDS WILL BECOME
SOUTHERLY AND THEN WESTERLY RATHER QUICKLY, WHICH IS NOT AS
CONDUCIVE TO MAINTAINING FOG AS SOUTHEASTERLY. BY THE AFTERNOON,
VERY DRY MID LEVEL AIR WILL BE IN PLACE, ALONG WITH A WARMING
BOUNDARY LAYER. UPPER 80S COULD BE EXPECTED ON THE WESTERN COUNTIES,
WITH MID 80S ELSEWHERE AS THE MID LEVEL HEIGHTS AND SUBSIDENCE
INCREASES. SUNDAY NIGHT WILL REMAIN RELATIVELY MILD AS LIGHT
SOUTHERLY WINDS AND THE SAME AIRMASS REMAINS IN PLACE. AT SOME
POINT, WEAK SHOWERS OR VIRGA MIGHT BEGIN TO SPREAD INTO WESTERN KANSAS
FROM THE NORTH. THIS WOULD BE ASSOCIATED WITH INCREASING CYCLONIC
FLOW AND INTENSIFYING JET ENERGY INTO THE CENTRAL PLAINS THAT IS
ASSOCIATED WITH A STRONGLY AMPLIFYING UPPER TROUGH OVER THE NORTHERN
PLAINS. A COLD SURFACE FRONT WILL DIVE INTO THE AREA BEFORE 12Z AND
MOVE RAPIDLY THROUGH ALL OF WESTERN KANSAS BY EARLY MORNING. WINDS
WILL PROBABLY AT LEAST BORDER ON OR EXCEED ADVISORY CRITERIA ACROSS
ALL OF WESTERN KANSAS AND MUCH OF CENTRAL KANSAS. THE GFS MOS WIND
SPEEDS SEEM MORE REASONABLE FOR THIS EPISODE, AND NUMERICAL MODELS
SEEM TO BE INCREASING WITH EACH RUN. COLD ADVECTION SHOULD LIMIT
HIGHS TO THE LOW 70S AT BEST MONDAY AFTERNOON.
A COOL NIGHT SHOULD BE EXPECTED MONDAY NIGHT INTO TUESDAY MORNING.
MOST OF THE MODEL OUTPUT ARE SOMEWHERE IN THE 40S WITH RESPECT TO
MINIMUM TEMPERATURES. A SLOW WARMING TREND IS THEN EXPECTED HEADING
INTO THE NEXT FEW DAYS IN THE MIDDLE TO LATE PART OF THE WEEK. WHILE
TUESDAY WILL SEE WARMING TEMPERATURES, WEDNESDAY APPEARS THE WARMEST
WITH HIGHS ON THE LATEST NAM WARMING TO NEAR 90S DEGREES NEAR THE
COLORADO LINE. ANOTHER WEAK COLD FRONT WILL ARRIVE LATE WEDNESDAY
AFTERNOON, WHICH COULD TEMPER HIGHS SEVERAL DEGREES LOWER FOR
THURSDAY AFTERNOON. CONSENSUS BETWEEN THE GFS AND ECMWF INDICATES
SHOWERS AND THUNDERSTORMS WOULD BE POSSIBLE ALONG THE CONVERGENCE
ZONE AS IT INTERACTS WITH A HIGHER THETA-E AIRMASS OVER SOUTH
CENTRAL KANSAS AND CENTRAL OKLAHOMA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1149 AM CDT SAT SEP 15 2012
SURFACE HIGH PRESSURE OVER KANSAS WILL KEEP VFR CONDITIONS
PREVAILING THROUGH THE 24 HOUR TAF PERIOD. CLEAR SKIES WILL
DOMINATE THE TAF SITES, BUT JUST EAST OF THE SITES NEAR MEDICINE
LODGE (P28) AND PRATT (PTT) MVFR CIGS AROUND BKN-OVC025-030 WILL
LINGER THIS AFTERNOON IN ISENTROPIC LIFT FROM OKLAHOMA. LIGHT AND
VARIABLE WINDS EARLY THIS AFTERNOON WILL SHIFT SOUTHEAST AT UNDER
10 KNOTS BY 20Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 53 84 52 72 / 0 0 10 10
GCK 51 87 51 71 / 0 0 10 10
EHA 51 87 52 71 / 0 0 10 10
LBL 50 86 52 73 / 0 0 0 0
HYS 53 85 55 70 / 0 0 10 20
P28 57 85 58 76 / 0 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURKE
SHORT TERM...BURKE
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS PADUCAH KY
650 PM CDT SUN SEP 16 2012
.UPDATE...
ISSUED 650 PM CDT SUN SEP 16 2012
REVISED AVIATION DISCUSSION FOR 00Z TAFS.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED 308 PM CDT SUN SEP 16 2012
THE WEAK SYSTEM RESPONSIBLE FOR THE SHOWERS LAST NIGHT AND EARLY
THIS MORNING DISSIPATED AS IT MOVED EAST TODAY. IN ITS WAKE...SOME
PARTIAL CLEARING DEVELOPED ACROSS THE LOWER OHIO VALLEY. WITH THE
SOLAR HEATING...A FEW ISOLATED SHOWERS POPPED UP NEAR KPOF THIS
AFTERNOON.
OF MORE SIGNIFICANCE IS A LARGER AREA OF SHOWERS AND EVEN A FEW
THUNDERSTORMS ALONG AND SOUTH OF INTERSTATE 40 AS OF 19Z. THE
MAJORITY OF THE MODELS BRING THIS AREA NORTHWARD INTO SE MISSOURI
AND SW KENTUCKY TONIGHT...AND EVENTUALLY UP INTO THE EVV AREA
SOMETIME LATE TONIGHT OR MONDAY MORNING. THE PRIMARY EXCEPTION IS
THE SREF...WHICH TENDS TO SUPPRESS THE SOUTHERN STREAM SHORTWAVE
AND ITS ASSOCIATED QPF TO OUR SOUTH. THE 15Z RUC MODEL WAS RATHER
AGGRESSIVE BRINGING MOISTURE NORTH FROM ARKANSAS...AND THIS WILL
BE THE BASIS FOR THROWING OUT THE SREF.
THE RATHER STRONG 500 MB SHORTWAVE OVER TEXAS WILL MOVE EAST
NORTHEAST TONIGHT...BACKING OUR MID LEVEL WINDS INTO THE
SOUTHWEST. THIS WILL OPEN THE DOOR FOR A SERIES OF VORT CENTERS
THAT WILL MOVE NORTHEAST INTO THE OHIO VALLEY OVERNIGHT AND
MONDAY. DEEP LAYER SOUTHERLY FLOW WILL BRING A SURGE OF HIGHER PW
AIR NORTHWARD...WITH PW VALUES CLIMBING ABOVE 1.5 INCHES BY
MONDAY. POPS WILL RISE INTO THE LIKELY CATEGORY OVERNIGHT ACROSS
FAR SOUTHERN PORTIONS OF THE FA...WITH CHANCE POPS ELSEWHERE.
LIKELY POPS WILL SPREAD NORTH AND EAST MONDAY ACROSS MOST OF
WESTERN KY AND SW INDIANA.
A STRONG COLD FRONT WILL SWING SOUTHEAST ACROSS THE LOWER OHIO
VALLEY ON MONDAY NIGHT. AS THIS COLD FRONT ENCOUNTERS MOISTURE
ASSOCIATED WITH THE SOUTHERN STREAM SHORTWAVE...NUMEROUS SHOWERS
AND SOME ISOLATED THUNDER WILL PERSIST ACROSS MUCH OF OUR REGION.
WHILE STORM TOTAL QPF IS GENERALLY UNDER AN INCH...THERE COULD BE
SOME ISOLATED HEAVIER AMOUNTS. HEAVIEST TOTALS WILL BE IN KHOP
AREA. DUE TO WIDESPREAD CLOUDS AND WEAK WIND FIELDS...CONVECTIVE
DEVELOPMENT SHOULD BE LIMITED IN COVERAGE AND INTENSITY.
ONCE THE COLD FRONT PASSES MONDAY NIGHT...WINDS WILL INCREASE FROM
THE NORTHWEST. 850 MB WINDS WILL BE AVERAGING 25 TO 30 KNOTS TUESDAY.
SURFACE WIND GUSTS MAY REACH 30 MPH WITH STRONG MIXING ON TUESDAY.
STRONG DRYING BEHIND THE FRONT WILL RESULT IN RAPID CLEARING ON
TUESDAY MORNING...BUT 850 MB TEMPS WILL BE FALLING QUICKLY INTO
THE SINGLE DIGITS. THEREFORE...HIGHS WILL NOT GET OUT OF THE 60S
DESPITE A FAIRLY MILD START TO THE DAY IN THE 50S.
TUESDAY NIGHT WILL BE CHILLY AS A SURFACE RIDGE PASSES OVER THE
OHIO VALLEY. CLEAR SKIES AND NEARLY CALM WINDS WILL BE FAVORABLE
FOR STRONG RADIATIONAL COOLING. MOS GUIDANCE IS OFTEN TOO HIGH IN
SUCH CASES...AND FORECAST WILL BE WEIGHTED TOWARD THE COOLER 2M
NAM TEMPS. THIS YIELDS UPPER 30S IN MANY PLACES...WHICH SUGGESTS
THE POSSIBILITY OF SOME PATCHY FROST.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED 308 PM CDT SUN SEP 16 2012
TROUGHING ALOFT OVER THE WESTERN GREAT LAKES TO BEGIN THE PERIOD
IS EXPECTED TO AMPLIFY AND DEVELOP SOUTHWARD TOWARD THE LOWER OHIO
VALLEY/MID MISSISSIPPI VALLEY FRIDAY INTO SATURDAY. CONFIDENCE HAS
IMPROVED IN KEEPING THE FORECAST DRY WEDNESDAY THROUGH THURSDAY
NIGHT...AS NO RECENT MODELS HAVE ROTATED A SIGNIFICANT ENOUGH
DISTURBANCE THROUGH THE BASE OF THE TROUGH TO DRAG PRECIPITATION
INTO THE FOUR STATE REGION.
CONFIDENCE IS ALSO INCREASING IN TIMING OF THE PRIMARY COLD FRONT
THROUGH THE REGION FRIDAY AND FRIDAY NIGHT...AS THE 12Z GFS AND
ECMWF BOTH HAVE THIS GENERAL TIMING. POPS ARE STILL RATHER LOW THESE
PERIODS...AS THE MODELS NEED TO SHOW SOME STABILITY FIRST.
ALSO...SURFACE RIDGING IS EXPECTED TO PERSIST BETWEEN HERE AND THE
GULF COAST...SO THERE WILL BE LITTLE IN THE WAY OF RETURN FLOW OF
MOISTURE INTO THE FRONT. THAT SAID...THE MID AND UPPER LEVEL FORCING
MAY BE STRONG ENOUGH TO GENERATE SOME ELEVATED INSTABILITY...SO KEPT
THUNDER MENTION AREAWIDE FRIDAY AND FRIDAY NIGHT.
SLIGHT POPS ARE FORECAST FOR SATURDAY AND SATURDAY NIGHT TO ACCOUNT
FOR THE 00Z ECMWF TIMING OF THE FRONT. THE 00Z ECMWF ENSEMBLES DID
SHOW SOME SUPPORT FOR THE OLD OPERATIONAL RUN...SO CANNOT RULE IT
OUT JUST YET.
AS FOR TEMPERATURES...IT WILL FEEL RATHER COOLISH WITH HIGHS NEAR 70
AND PLENTY OF SUNSHINE WEDNESDAY. A NICE WARMING TREND IS EXPECTED
THURSDAY AND FRIDAY WITH A FEW 80S POSSIBLE ON FRIDAY. LOOKS LIKE
PLEASANT EARLY FALL CONDITIONS FOR NEXT WEEKEND...ESPECIALLY IF THE
OLD ECMWF IS NOT RIGHT. TEMPERATURES WILL BE A COUPLE OF CATEGORIES
BELOW NORMAL...BUT STILL IN THE 70S FOR HIGHS.
&&
.AVIATION...
ISSUED AT 650 PM CDT SUN SEP 16 2012
VFR CONDITIONS WILL START OFF THIS EVENING. HOWEVER...A NORTHWARD
RETURN OF SHOWERS AND LOCAL IFR CONDITIONS IS EXPECTED OVERNIGHT.
IFR CEILINGS AND VISIBILITIES WILL IMPACT PRIMARILY THE KCGI/KPAH
SITES MONDAY MORNING. THE SHOWER ACTIVITY AND MVFR CEILINGS AND
VISIBILITIES WILL SPREAD ACROSS THE KEVV/KOWB SITES AFTER DAYBREAK
MONDAY. AN IMPROVEMENT IN CEILINGS AND VISIBILITIES MONDAY AFTERNOON
WILL BE ACCOMPANIED BY THE POTENTIAL FOR A FEW THUNDERSTORMS. LIGHT
WINDS OVERNIGHT WILL BECOME SOUTHERLY ON MONDAY.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
MO...NONE.
IL...NONE.
IN...NONE.
&&
$$
SHORT TERM...MY
LONG TERM....DRS
AVIATION...RJP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1000 AM CDT SAT SEP 15 2012
.UPDATE...
ISSUED AT 1000 AM CDT SAT SEP 15 2012
RAIN OVER SW MISSOURI IS ENCOUNTERING DRY HIGH PRESSURE AS IT MOVES
EAST INTO THE MISSISSIPPI VALLEY. THE 1000/500 MB LAYER MEAN RH FROM
THE 09Z RUC MODEL APPEARS TO HAVE A GOOD HANDLE ON THE LEADING EDGE
OF THE THICKER OVERCAST AND RAIN AREAS. BASED ON THE RUC MEAN
RH...THE LEADING EDGE WILL DRIFT ONLY SLIGHTLY EASTWARD ACROSS SE
MISSOURI TODAY. UPDATED FORECAST TO SHARPEN THE POP GRADIENT ACROSS
SE MISSOURI. TEMP GRADIENT WAS ALSO SHARPENED...BASED ON THE LARGE
DIFFERENCE IN EXPECTED CLOUDS AND WEATHER ACROSS THE REGION.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 1218 AM CDT SAT SEP 15 2012
AN UPPER LEVEL CUT OFF LOW REMAINED OVER THE DESERT SOUTHWEST THIS
MORNING. THIS LOW WAS PUMPING UP GULF MOISTURE OVER THROUGH THE
GULF STATES AND INTO AR. A WEAK DIRTY HIGH WAS HOLDING IN PLACE
OVER THE PAH FA KEEPING SHOWERS AT BAY FOR NOW. HOWEVER THIS
CLOSED LOW WILL OPEN UP AND START TO INVADE THE FA AS WE HEAD
THROUGH THE WEEKEND. THE MODELS ARE SHOWING A LATER ONSET FROM ONE
RUN TO THE NEXT AS THE STUBBORN HIGH IS SLOW TO DEPART. HOWEVER
THE HIGH WILL BE FORCED EAST OF THE AREA AS THE UPPER LEVEL OPEN
WAVE MAKES ITS WAY INTO THE HEARTLAND. AS FOR NOW THE SOUTHERN
PORTIONS OF THE AREA WOULD HAVE THE BEST CHANCE AND MOST QPF THIS
WEEKEND. HOWEVER BY MONDAY THIS OPEN WAVE PHASES WITH A SHARPENING
LONG WAVE TROUGH AND KICKS A COLD FRONT THROUGH THE
AREA...RESULTING IN BETTER COVERAGE OF RAIN IN THE FORM OF
THUNDERSTORMS MOST LIKELY MONDAY AND MONDAY NIGHT. CURRENTLY ALL
PARAMETERS ARE SUGGESTING NO SEVERE WX EXPECTED AT THIS TIME.
ONLY MINOR EDITS TO TEMPS FOR COLLAB PURPOSES MAINLY.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 1218 AM CDT SAT SEP 15 2012
THE PATTERN IN THE LONG TERM WILL BE HIGHLY AMPLIFIED AND STAGNANT
WITH A DEEP TROF COVERING MUCH OF THE NORTH CENTRAL U.S. AND GREAT
LAKES REGION...WITH A RIDGE PERSISTENT OVER THE FAR WEST U.S.
DEPARTING MOISTURE TUESDAY MORNING WILL BE FOLLOWED BY DRY WEATHER
THROUGH WEDNESDAY NIGHT. A WEAKENING FRONTAL SYSTEM WILL BRING A
SMALL CHANCE OF CONVECTION TO THE REGION THURSDAY...FOLLOWED BY A
BETTER CHANCE OF CONVECTION THURSDAY NIGHT INTO FRIDAY...WHEN A
STRONG FRONT IS FORECAST TO MOVE THROUGH.
&&
.AVIATION...
ISSUED AT 614 AM CDT SAT SEP 15 2012
CONSIDERABLE HIGH CLOUDS WITH NE WINDS AOB 10 KTS. THERE IS A LOW
PROB OF -SHRA AT KPAH AND KCGI BUT NOT IN THE TAFS AT THIS TIME
GIVEN LOW CONFIDENCE.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...MY
SHORT TERM/LONG TERM...KH/CN
AVIATION...CN
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
955 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A COLD FRONT DRAPED ACROSS THE SAINT LAWRENCE VALLEY WILL CROSS
THE REGION THIS MORNING ACCOMPANIED BY SCATTERED SHOWERS. HIGH
PRESSURE AND DRIER AIR FOLLOWS LATE SATURDAY THROUGH MONDAY. A
WARM FRONT WILL LIFT NORTH THROUGH NEW ENGLAND TUESDAY WHILE LOW
PRESSURE LIFTS NORTH OF THE REGION. DRIER AIR FILTERS IN WEDNESDAY
THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...A LINE OF SHOWERS ALONG A COLD FRONT CONTINUES TO PUSH
EAST THIS MORNING. A FEW CONVECTIVE CELLS ARE TRYING TO GET GOING
IN WEAK CAPE NEAR SKOWHEGAN. NOT EXPECTING MUCH TO COME OF THIS
BUT INCLUDED ISOLATED LIGHTNING FOR A COUPLE HOURS. HRRR GENERATES
A FEW MORE HOURS OF SHOWERS BUT THIS MAY BE OVERDONE. THERE IS AN
AREA OF CLEARING BEHIND THE BOUNDARY BUT IT QUICKLY FILLED IN WITH
COLD AIR STRATUS WHICH IS PUSHING SOUTHEAST OUT OF VERMONT AND NY.
WINDS ARE GUSTING INTO THE UPPER TEENS AND LOWER 20S. UPDATED THE
FORECAST TO REFLECT CURRENT CONDITIONS AND TREND POPS EAST.
&&
PREVIOUS DISCUSSION...COLD FNT IS APPROACHING WRN PORTIONS OF
THE CWFA ATTM...WITH MOSTLY POST FRONTAL PCPN. REGIONAL 88DS ARE
SHOWING A LOT MORE BARK THAN BITE WITH THE FRONTAL PCPN. WHILE
THERE IS A CONCENTRATED BAND ADVANCING EWD...WITH EMBEDDED ECHOES
ON THE ORDER OF 40 DBZ...MUCH OF THIS IS FAILING TO REACH THE
GROUND. SEEING A LOT OF 10SM -RA FROM REGIONAL METAR OBS...WITH
HEAVIEST RAFL...AROUND A TENTH...OCCURRING INVOF KALB. SOME OF
THIS MAY HOLD TOGETHER INTO SRN NH...BUT EXPECT A CONTINUED
WEAKENING TREND THRU THE EARLY MORNING. WITH RA STRUGGLING TO
AMOUNT TO MORE THAN A TRACE PCPN...HAVE KEPT POP BLO LIKELY...WITH
HIGHEST CHC IN THE MTNS.
ONCE FNT CROSSES THE CWFA...WILL SEE RAPID CLEARING OUTSIDE OF THE
MTNS FROM SW TO NE. CAA AND DIURNAL HEATING WILL PROMOTE BOUNDARY
LAYER MIXING AND HELP 20-25 KT WIND GUSTS REACH THE SFC THIS AFTN.
BUOYS OFF OSWEGO NY ARE GUSTING TO NEAR 25 KT ATTM...SUPPORTING
SIMILAR VALUES OVER LAND TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE REGION WILL REMAIN UNDER CYCLONIC FLOW ALOFT TNGT...WHILE SFC
SYSTEM LIFTS WELL TO THE NE. LACK OF DEEP MOISTURE WILL PRECLUDE
MUCH IN THE WAY OF CLOUDS IN THE MTNS PAST THIS AFTN. SO EXPECTING
CLEAR SKIES...AND A WEAKENING GRADIENT THRU THE NGT. THIS WILL
ALLOW EFFICIENT RADIATIONAL COOLING...WITH READINGS IN THE LOW TO
MID 30S IN THE NRN MTNS. HAVE GONE WITH A FROST ADVISORY FOR THE
ZONES MOST LIKELY TO SEE WIDESPREAD FROST.
AS HIGH PRES BUILDS EWD...QUIET AND SUNNY DAY EXPECTED FOR SUN.
WILL STILL SEE SOME GUSTY WINDS AS BOUNDARY LAYER MIXES OUT DURING
THE DAY. OTHERWISE...NEAR 70 FOR THE COASTAL AREAS AND 60S FOR
MTNS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
MAINLY CLEAR AND QUIET CONDITIONS ARE EXPECTED TO CONTINUE DURING
THE PERIOD SUNDAY NIGHT INTO MONDAY. A LARGE AREA OF SURFACE HIGH
PRESSURE WILL GRADUALLY EASE OFF THE COAST DURING THIS PERIOD.
THEREAFTER...THE FLOW BECOME MERIDIONAL WITH TIME AS LOW PRESSURE
INTENSIFIES AND PASSES BY TO OUR WEST ON TUESDAY. THIS WILL SET UP
A STRONG AND VERY MOIST SOUTHERLY FLOW FROM THE ATLANTIC WATERS.
HIGHEST QPF IS EXPECTED WEST OF OUR REGION...BUT WE ARE STILL
ANTICIPATING SOME WELL NEEDED RAINFALL...MAINLY TUESDAY NIGHT.
LOW PRESSURE WILL CONTINUE TO INTENSIFY AS IT MOVES INTO CANADA
WEDNESDAY...DRAGGING A COLD FRONT THROUGH NORTHERN NEW ENGLAND.
THE CANADIAN GEM IS THE SLOWEST MODEL BRINGING THE CLOUDS AND SCT
-SHRA OFF THE COAST WEDNESDAY MORNING. THIS APPEARS TO BE A
REASONABLE SOLUTION CONSIDERING THE UPPER LEVEL TROUGH REMAINS WELL
TO THE WEST BY 12Z WEDNESDAY.
AFTER SOME DRY AND CHILLY WEATHER CONDITIONS THURSDAY AND
FRIDAY...A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL GRADUALLY
APPROACH FROM THE WEST BY NEXT WEEKEND. THIS WILL BRING MORE
UNSETTLED CONDITIONS BACK TO THE REGION.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...LOCAL IFR/LIFR PSBL WITH LOW CLOUDS/FOG AHEAD OF COLD
FNT. COULD SEE ISOLD MVFR CONDS IN SHRA ALONG FNT...THEN RAPID
CLEARING TO VFR CONDS EXPECTED BEHIND IT. WILL SEE CLOUDS ACROSS
THE NRN MTNS...BUT LACK OF APPRECIABLE MOISTURE SHOULD KEEP CIGS
ABV 3KFT. GUSTY WLY WINDS EXPECTED THIS AFTN..AOA 20 KT.
LONG TERM...VFR SUNDAY NIGHT AND MONDAY. CONDITIONS WILL
DETERIORATE TO IFR AND LIFR IN RAIN AND FOG TUESDAY AND WEDNESDAY
FROM WEST TO EAST AS A WARM FRONT LIFTS THROUGH THE AREA.
THEREAFTER...CONDITIONS IMPROVE TO VFR.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL BUILD THIS AFTN AS COLD FNT
CROSSES THE WATERS. ATTM WINDS LOOK TO REMAIN JUST BLO SCA
THRESHOLDS...THOUGH SEAS COULD BUILD ABV 5 FT ON THE OUTER WATERS
LATE TNGT.
LONG TERM...WINDS AND SEAS MAY INCREASE TO NEAR SCA CONDITIONS
TUESDAY AFTERNOON INTO WEDNESDAY AS LOW PRESSURE PASSES JUST NORTH
OF THE WATERS...PRODUCING A GUSTY AND PERSISTENT SOUTHERLY FLOW.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM EDT SUNDAY FOR
MEZ007-008-012.
NH...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM EDT SUNDAY FOR
NHZ001>004.
MARINE...NONE.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1045 PM EDT SUN SEP 16 2012
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE MONDAY BEFORE WIDESPREAD RAIN
SHOWERS ARRIVE MONDAY NIGHT AND TUESDAY. HIGH PRESSURE WILL RETURN
MID-WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
03Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO REDUCE SKY
GRIDS AS LITTLE CIRRUS ADVECTS ACROSS THE AREA OVERNIGHT. THE
REST OF THE PREVIOUS DISCUSSION REMAINS THE SAME.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A VERY DRY ZONAL FLOW. AT THE SURFACE, A 1020MB HIGH IS
CENTERED JUST OFF THE MID-ATLANTIC COAST AND EXTENDS INTO THE
UPPER OHIO VALLEY. WITH A DEEP LAYER OF DRY AIR IN PLACE, SKIES
ARE MOSTLY CLEAR THIS EVENING. THE ONLY EXCEPTION TO CLEAR SKIES
IS SOME THIN CIRRUS ADVECTING INTO THE AREA FROM THE WEST.
TONIGHT...THE SURFACE HIGH WILL SHIFT FURTHER OFF THE MID-ATLANTIC
COAST AS DRY AIR ALOFT REMAINS IN PLACE ACROSS THE AREA. THUS,
ANOTHER DRY NIGHT IS AHEAD. TD DEPRESSIONS ARE TRENDING GREATER
THAN THE PREVIOUS NIGHT AND THUS PATCHY FOG ALONG THE RIVER
VALLEYS IS ANTICIPATED TO BE MORE SCARCE AND THUS NO MENTION THERE.
ONLY LOCATION WITH PATCHY FOG MENTIONED IS ACROSS THE EASTERN
RIDGES WHERE LAMP/NAM GUIDANCE SUPPORT LOW-LEVEL MOISTURE ON THE
INCREASE NEAR DAWN. SOME RADIATIONAL COOLING WILL OCCUR TONIGHT,
ALTHOUGH NOT AS STRONG AS LAST NIGHT DUE A WEAK SOUTHERLY FLOW ON
THE WEST SIDE OF THE HIGH. LOW TEMPS TONIGHT ARE GENERALLY 1-2
DEGREES COOLER THAN LAMP GUIDANCE, IN THE MID TO UPPER 40S.
MONDAY...THE HIGH WILL SLIDE FURTHER EASTWARD WITH THE MID-LEVEL
FLOW GETTING MORE OF A SOUTHWEST COMPONENT AHEAD OF A CLOSED OVER
THE WESTERN GULF COAST. THIS FEATURE ALONG WITH AN AMPLIFYING
TROUGH MOVING INTO THE UPPER MIDWEST WILL AID IN PULLING A FRONTAL
BOUNDARY NORTHWARD INTO WV BY LATE IN THE DAY. AS THE BOUNDARY
MOVES NORTHWARD, THE CHANCE OF LIGHT RAIN ENTERS THE FORECAST LATE
IN THE DAY WITH CLOUD COVERAGE INCREASING FOR LOCATIONS SOUTH OF
PITTSBURGH. FOR TEMPS, HIGHS ARE FAIRLY CLOSE TO A MAV/MET BLEND,
WITH HIGHS RANGING FROM NEAR 70 ACROSS THE EASTERN RIDGES TO THE
MID 70S ELSEWHERE.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
STRONG SHRTWV TROF WILL AMPLIFY FURTHER MON NGT WITH ATTENDANT SFC
CYCLOGENESIS IN ERN GRTLKS RGN. VERY MOIST AMS CHARACTERIZED BY
2SD PWATS WILL BE ADVCTD INTO RGN AHD OF SURGING CDFNT.
LEAD SHRTWV TROF AND STRONG WARM AIR ADVCTN PATTERN XPCD TO
SUPPORT WDSPRD SHWRS IN SHARPENING WARM SECTOR MON NGT. A SECOND
WAVE OF SHWRS WILL DVLP ALONG ADVCG CDFNT TUE AFTN AS UPR TROF
BCMS NEGATIVELY TILTED AND LIFTS NEWD IN RESPONSE TO EJECTING H5
JET.
OWING TO SUCH ANOMALOUSLY HIGH PWATS...STRONG DYNAMICAL FORCING
AND APRCHG BNDRY...SGFNT RAINFALL IS XPCD...WITH 1.0-2.0 IN AMTS
FCSTD NRLY AREA-WIDE. HIGHEST AMTS XPCD TO BE IN ERN ZONES...
CLOSEST TO THE H9 LOW-LVL JET AND PLUME OF GREATEST MSTR. ERN
PORTION OF FCST AREA IS OUTLOOKED FOR SLGT RISK OF EXCESSIVE
RAINFALL...AND CANNOT DISAGREE WITH THE GEOGRAPHY OF THE RISK.
THREAT FOR LCL FLOODING WILL BE HIGHLIGHTED IN HWO.
OTHER CONCERN WILL BE SVR WX POTENTIAL. FCST AREA WILL BE LOCATED
IN HIGH SHEAR/LOW CAPE ENVT ON TUE. DESPITE CONTG RAINFALL...
ADVCTN OF HIGH THETA-E AIR WILL KEEP BNDRY LYR BETTER-MIXED THAN
USUAL OVNGT. WITH DP-LYR SHEAR ORIENTED PARALLEL TO CDFNT...SHWRS
ALONG THE BNDRY XPCD TO TAKE LINEAR MODE AS THE BNDRY ADVCS.
HODOGRAPHS IN ERN ZONES FAVOR POTL FOR DMGG WIND GUSTS AND
MESOVORTICES WITH ANY LINEAR STRUCTURES. ONLY LMTD LGTNG XPCD WITH
THIS ACTIVITY OWING TO SHALLOW INSTBY PROFILE.
CLD CVR WILL BE EXTENSIVE FOR MUCH OF MON NGT AND TUE. AS A
RESULT OF THE CLD CVR AND BNDRY LYR MSTR...MON NGT MINIMA WILL BE
ELEVATED IN THE UPR 50S-LWR 60S. TUE MAXIMA WILL NOT SHOW MUCH
INCR AND WILL RMN GENLY IN THE MID-UPR 60S.
PCPN WILL END QUICKLY TUE NGT AS CDFNT CROSSES RGN AND SCOURS OUT
ANY MSTR. CLD CVR AND SHWRS MAY INCR FROM THE NW ON TUE NGT AS
FLOW BCMS NWLY OFF THE GRTLKS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MDLS RMN IN CONSENSUS WITH GENL SOLN OF BROAD...HIGH AMPLITUDE
TROF DVLPMNT/SHIFT ACRS ERN NORTH AMERICA FOLLOWING PASSAGE OF THE
TUESDAY CDFNT. HOWEVER...PROFOUND DIFFERENCES CAN BE FOUND IN THE
POSITION OF THE ACTUAL TROF AXIS...OVRALL MAGNITUDE...AND
POSITION OF EXPECTED LATE-PD CUTOFF AS SHRTWVS REINFORCE THE TROF.
REGARDLESS...BLDG SFC HIGH FOLLOWING THE FRONT WL DRY
WEDNESDAY...BUT INCRSG...ALBEIT SLGT CHC TO CHC POPS WERE FORECAST
THEREAFTER AS SHRTWVS MOV THRU THE BASE OF THE PARENT TROF.
TEMPERATURES UNDR THIS PATN WL NOT EXCEED THE SEASONAL NORMALS.
EXPECT READINGS TO AVERAGE OUT ABOUT 5 TO 10 DEGREES UNDR.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS ARE FORECAST FOR THE MAJORITY OF THE TAF PERIOD AS
HIGH PRESSURE SHIFTS EAST OF THE AREA AND A FRONTAL BOUNDARY
BEGINS TO APPROACH FROM THE SOUTHWEST. THE ONE EXCEPTION OVERNIGHT
IS AT KHLG, WHERE A TEMPO GROUP IS FORECAST FOR MVFR VISILITIES
WITH POTENTIAL RIVER VALLEY FOG THERE.
AS THE FRONTAL BOUNDARY APPROACHES FROM THE SOUTH TOMORROW, THE
CHANCE OF LIGHT RAIN WILL BEGIN LATE IN THE DAY AT KMGW/KZZV AND BEGIN
TO SPREAD NORTHWARD INTO THE PIT METRO TERMINALS BY 00Z TUESDAY.
.OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/...
WDSPRD VSBY/CIG RESTRICTIONS XPCD MON NGT AND TUE AS LOW-LVL MSTR
INCRS AND SHWRS BCM MORE WDSPRD. WIND GUSTS MAY EXCEED 20 KTS IN
ADVC OF AND WITH CDFNT. VFR CONDS XPCD RMNDR OF WK AS HIPRES
RETURNS TO THE RGN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
UPDATE...KRAMAR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1025 PM EDT SUN SEP 16 2012
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE MONDAY BEFORE WIDESPREAD RAIN ARRIVES
MONDAY NIGHT AND TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
03Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO REDUCE SKY
GRIDS AS LITTLE CIRRUS ADVECTS ACROSS THE AREA OVERNIGHT. THE
REST OF THE PREVIOUS DISCUSSION REMAINS THE SAME.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A VERY DRY ZONAL FLOW. AT THE SURFACE, A 1020MB HIGH IS
CENTERED JUST OFF THE MID-ATLANTIC COAST AND EXTENDS INTO THE
UPPER OHIO VALLEY. WITH A DEEP LAYER OF DRY AIR IN PLACE, SKIES
ARE MOSTLY CLEAR THIS EVENING. THE ONLY EXCEPTION TO CLEAR SKIES
IS SOME THIN CIRRUS ADVECTING INTO THE AREA FROM THE WEST.
TONIGHT...THE SURFACE HIGH WILL SHIFT FURTHER OFF THE MID-ATLANTIC
COAST AS DRY AIR ALOFT REMAINS IN PLACE ACROSS THE AREA. THUS,
ANOTHER DRY NIGHT IS AHEAD. TD DEPRESSIONS ARE TRENDING GREATER
THAN THE PREVIOUS NIGHT AND THUS PATCHY FOG ALONG THE RIVER
VALLEYS IS ANTICIPATED TO BE MORE SCARCE AND THUS NO MENTION THERE.
ONLY LOCATION WITH PATCHY FOG MENTIONED IS ACROSS THE EASTERN
RIDGES WHERE LAMP/NAM GUIDANCE SUPPORT LOW-LEVEL MOISTURE ON THE
INCREASE NEAR DAWN. SOME RADIATIONAL COOLING WILL OCCUR TONIGHT,
ALTHOUGH NOT AS STRONG AS LAST NIGHT DUE A WEAK SOUTHERLY FLOW ON
THE WEST SIDE OF THE HIGH. LOW TEMPS TONIGHT ARE GENERALLY 1-2
DEGREES COOLER THAN LAMP GUIDANCE, IN THE MID TO UPPER 40S.
MONDAY...THE HIGH WILL SLIDE FURTHER EASTWARD WITH THE MID-LEVEL
FLOW GETTING MORE OF A SOUTHWEST COMPONENT AHEAD OF A CLOSED OVER
THE WESTERN GULF COAST. THIS FEATURE ALONG WITH AN AMPLIFYING
TROUGH MOVING INTO THE UPPER MIDWEST WILL AID IN PULLING A FRONTAL
BOUNDARY NORTHWARD INTO WV BY LATE IN THE DAY. AS THE BOUNDARY
MOVES NORTHWARD, THE CHANCE OF LIGHT RAIN ENTERS THE FORECAST LATE
IN THE DAY WITH CLOUD COVERAGE INCREASING FOR LOCATIONS SOUTH OF
PITTSBURGH. FOR TEMPS, HIGHS ARE FAIRLY CLOSE TO A MAV/MET BLEND,
WITH HIGHS RANGING FROM NEAR 70 ACROSS THE EASTERN RIDGES TO THE
MID 70S ELSEWHERE.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
SHORTWAVE FROM THE SOUTH WILL BE PHASING WITH A LARGE UPPER LEVEL
TROUGH STRETCHING NORTH-SOUTH ACROSS MUCH OF THE UNITED STATES.
LITTLE RAIN IS EXPECTED MONDAY EVENING NORTH OF THE MASON-DIXON
LINE...BUT RAINFALL WILL PICK UP OVERNIGHT IN ALL LOCATIONS. MODELS
HAVE BACKED OFF SLIGHTLY ON PRECIPITATION AMOUNTS...BUT STILL THINK
THAT MAXIMUM MODEL VALUES ARE OVERDONE CONSIDERING HOW QUICKLY
SURFACE LOW PRESSURE WILL BE RACING TO THE NORTH. CURRENT FORECAST
HAS RAIN TOTALS RANGING FROM 1 INCHES IN NORTHWESTERN COUNTIES TO 2
INCHES IN THE WV/MD RIDGES. CONSIDERING RECENT DRY CONDITIONS...AND
FLASH FLOOD GUIDANCE OF AT LEAST 2.5 INCHES IN 6 HOURS...DO NOT SEE
A FLOODING THREAT AT THIS TIME.
A POTENTIAL THREAT WILL BE STRONG LOW LEVEL JET LATE MONDAY NIGHT
INTO TUESDAY MORNING MOVING ACROSS NORTHERN WEST VIRGINIA AND
SOUTHWESTERN PENNSYLVANIA. ALTHOUGH THERE IS ALMOST ZERO INSTABILITY
TO GENERATE ANY THUNDERSTORMS...CANNOT RULE OUT THE POSSIBILITY THAT
STRONGER WINDS COULD MIX DOWN TO THE SURFACE IN HEAVIER RAIN
SHOWERS. THIS THREAT SHOULD DIMINISH BY TUESDAY AFTERNOON AS THE
SURFACE LOW AND LLJ MOVE INTO CENTRAL/EASTERN PENNSYLVANIA.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MDLS RMN IN CONSENSUS WITH GENL SOLN OF BROAD...HIGH AMPLITUDE
TROF DVLPMNT/SHIFT ACRS ERN NORTH AMERICA FOLLOWING PASSAGE OF THE
TUESDAY CDFNT. HOWEVER...PROFOUND DIFFERENCES CAN BE FOUND IN THE
POSITION OF THE ACTUAL TROF AXIS...OVRALL MAGNITUDE...AND
POSITION OF EXPECTED LATE-PD CUTOFF AS SHRTWVS REINFORCE THE TROF.
REGARDLESS...BLDG SFC HIGH FOLLOWING THE FRONT WL DRY
WEDNESDAY...BUT INCRSG...ALBEIT SLGT CHC TO CHC POPS WERE FORECAST
THEREAFTER AS SHRTWVS MOV THRU THE BASE OF THE PARENT TROF.
TEMPERATURES UNDR THIS PATN WL NOT EXCEED THE SEASONAL NORMALS.
EXPECT READINGS TO AVERAGE OUT ABOUT 5 TO 10 DEGREES UNDR.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS ARE FORECAST FOR THE MAJORITY OF THE TAF PERIOD AS
HIGH PRESSURE SHIFTS EAST OF THE AREA AND A FRONTAL BOUNDARY
BEGINS TO APPROACH FROM THE SOUTHWEST. THE ONE EXCEPTION OVERNIGHT
IS AT KHLG, WHERE A TEMPO GROUP IS FORECAST FOR MVFR VISILITIES
WITH POTENTIAL RIVER VALLEY FOG THERE.
AS THE FRONTAL BOUNDARY APPROACHES FROM THE SOUTH TOMORROW, THE
CHANCE OF LIGHT RAIN WILL BEGIN LATE IN THE DAY AT KMGW/KZZV AND BEGIN
TO SPREAD NORTHWARD INTO THE PIT METRO TERMINALS BY 00Z TUESDAY.
.OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/...
WIDESPREAD RESTRICTIONS IN STRATUS AND RAIN CAN BE ANTICIPATED FOR
MONDAY NIGHT AND TUESDAY AS LOW PRESSURE DEVELOPS AND SLIDES A
COLD FRONT ACROSS THE REGION. LOW-LEVEL WIND SHEAR AND SURFACE GUSTS
EXCEEDING 20 KTS ARE ALSO POSSIBLE IN ADVANCE OF...AND WITH THE
COLD FRONT. GENERAL VFR WILL RETURN AS HIGH PRESSURE BUILDS FOR THE
LATTER HALF OF THE WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
802 PM EDT SUN SEP 16 2012
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE MONDAY BEFORE WIDESPREAD RAIN ARRIVES
MONDAY NIGHT AND TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
00Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED WITH ONLY
A MINOR ADJUSTMENT TO REMOVE PATCHY FOG MENTION ACROSS MOST OF
THE AREA.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A VERY DRY ZONAL FLOW. AT THE SURFACE, A 1020MB HIGH IS
CENTERED JUST OFF THE MID-ATLANTIC COAST AND EXTENDS INTO THE
UPPER OHIO VALLEY. WITH A DEEP LAYER OF DRY AIR IN PLACE, SKIES
ARE MOSTLY CLEAR THIS EVENING. THE ONLY EXCEPTION TO CLEAR SKIES
IS SOME THIN CIRRUS ADVECTING INTO THE AREA FROM THE WEST.
TONIGHT...THE SURFACE HIGH WILL SHIFT FURTHER OFF THE MID-ATLANTIC
COAST AS DRY AIR ALOFT REMAINS IN PLACE ACROSS THE AREA. THUS,
ANOTHER DRY NIGHT IS AHEAD. TD DEPRESSIONS ARE TRENDING GREATER
THAN THE PREVIOUS NIGHT AND THUS PATCHY FOG ALONG THE RIVER
VALLEYS IS ANTICIPATED TO BE MORE SCARCE AND THUS NO MENTION THERE.
ONLY LOCATION WITH PATCHY FOG MENTIONED IS ACROSS THE EASTERN
RIDGES WHERE LAMP/NAM GUIDANCE SUPPORT LOW-LEVEL MOISTURE ON THE
INCREASE NEAR DAWN. SOME RADIATIONAL COOLING WILL OCCUR TONIGHT,
ALTHOUGH NOT AS STRONG AS LAST NIGHT DUE A WEAK SOUTHERLY FLOW ON
THE WEST SIDE OF THE HIGH. LOW TEMPS TONIGHT ARE GENERALLY 1-2
DEGREES COOLER THAN LAMP GUIDANCE, IN THE MID TO UPPER 40S.
MONDAY...THE HIGH WILL SLIDE FURTHER EASTWARD WITH THE MID-LEVEL
FLOW GETTING MORE OF A SOUTHWEST COMPONENT AHEAD OF A CLOSED OVER
THE WESTERN GULF COAST. THIS FEATURE ALONG WITH AN AMPLIFYING
TROUGH MOVING INTO THE UPPER MIDWEST WILL AID IN PULLING A FRONTAL
BOUNDARY NORTHWARD INTO WV BY LATE IN THE DAY. AS THE BOUNDARY
MOVES NORTHWARD, THE CHANCE OF LIGHT RAIN ENTERS THE FORECAST LATE
IN THE DAY WITH CLOUD COVERAGE INCREASING FOR LOCATIONS SOUTH OF
PITTSBURGH. FOR TEMPS, HIGHS ARE FAIRLY CLOSE TO A MAV/MET BLEND,
WITH HIGHS RANGING FROM NEAR 70 ACROSS THE EASTERN RIDGES TO THE
MID 70S ELSEWHERE.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
SHORTWAVE FROM THE SOUTH WILL BE PHASING WITH A LARGE UPPER LEVEL
TROUGH STRETCHING NORTH-SOUTH ACROSS MUCH OF THE UNITED STATES.
LITTLE RAIN IS EXPECTED MONDAY EVENING NORTH OF THE MASON-DIXON
LINE...BUT RAINFALL WILL PICK UP OVERNIGHT IN ALL LOCATIONS. MODELS
HAVE BACKED OFF SLIGHTLY ON PRECIPITATION AMOUNTS...BUT STILL THINK
THAT MAXIMUM MODEL VALUES ARE OVERDONE CONSIDERING HOW QUICKLY
SURFACE LOW PRESSURE WILL BE RACING TO THE NORTH. CURRENT FORECAST
HAS RAIN TOTALS RANGING FROM 1 INCHES IN NORTHWESTERN COUNTIES TO 2
INCHES IN THE WV/MD RIDGES. CONSIDERING RECENT DRY CONDITIONS...AND
FLASH FLOOD GUIDANCE OF AT LEAST 2.5 INCHES IN 6 HOURS...DO NOT SEE
A FLOODING THREAT AT THIS TIME.
A POTENTIAL THREAT WILL BE STRONG LOW LEVEL JET LATE MONDAY NIGHT
INTO TUESDAY MORNING MOVING ACROSS NORTHERN WEST VIRGINIA AND
SOUTHWESTERN PENNSYLVANIA. ALTHOUGH THERE IS ALMOST ZERO INSTABILITY
TO GENERATE ANY THUNDERSTORMS...CANNOT RULE OUT THE POSSIBILITY THAT
STRONGER WINDS COULD MIX DOWN TO THE SURFACE IN HEAVIER RAIN
SHOWERS. THIS THREAT SHOULD DIMINISH BY TUESDAY AFTERNOON AS THE
SURFACE LOW AND LLJ MOVE INTO CENTRAL/EASTERN PENNSYLVANIA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MDLS RMN IN CONSENSUS WITH GENL SOLN OF BROAD...HIGH AMPLITUDE
TROF DVLPMNT/SHIFT ACRS ERN NORTH AMERICA FOLLOWING PASSAGE OF THE
TUESDAY CDFNT. HOWEVER...PROFOUND DIFFERENCES CAN BE FOUND IN THE
POSITION OF THE ACTUAL TROF AXIS...OVRALL MAGNITUDE...AND
POSITION OF EXPECTED LATE-PD CUTOFF AS SHRTWVS REINFORCE THE TROF.
REGARDLESS...BLDG SFC HIGH FOLLOWING THE FRONT WL DRY
WEDNESDAY...BUT INCRSG...ALBEIT SLGT CHC TO CHC POPS WERE FORECAST
THEREAFTER AS SHRTWVS MOV THRU THE BASE OF THE PARENT TROF.
TEMPERATURES UNDR THIS PATN WL NOT EXCEED THE SEASONAL NORMALS.
EXPECT READINGS TO AVERAGE OUT ABOUT 5 TO 10 DEGREES UNDR.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS ARE FORECAST FOR THE MAJORITY OF THE TAF PERIOD AS
HIGH PRESSURE SHIFTS EAST OF THE AREA AND A FRONTAL BOUNDARY
BEGINS TO APPROACH FROM THE SOUTHWEST. THE ONE EXCEPTION OVERNIGHT
IS AT KHLG, WHERE A TEMPO GROUP IS FORECAST FOR MVFR VISILITIES
WITH POTENTIAL RIVER VALLEY FOG THERE.
AS THE FRONTAL BOUNDARY APPROACHES FROM THE SOUTH TOMORROW, THE
CHANCE OF LIGHT RAIN WILL BEGIN LATE IN THE DAY AT KMGW/KZZV AND BEGIN
TO SPREAD NORTHWARD INTO THE PIT METRO TERMINALS BY 00Z TUESDAY.
.OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/...
WIDESPREAD RESTRICTIONS IN STRATUS AND RAIN CAN BE ANTICIPATED FOR
MONDAY NIGHT AND TUESDAY AS LOW PRESSURE DEVELOPS AND SLIDES A
COLD FRONT ACROSS THE REGION. LOW-LEVEL WIND SHEAR AND SURFACE GUSTS
EXCEEDING 20 KTS ARE ALSO POSSIBLE IN ADVANCE OF...AND WITH THE
COLD FRONT. GENERAL VFR WILL RETURN AS HIGH PRESSURE BUILDS FOR THE
LATTER HALF OF THE WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
201 AM EDT SAT SEP 15 2012
.SYNOPSIS...
DRY CONDITIONS AND SEASONABLE TEMPERATURES WILL CONTINUE AS HIGH
PRESSURE REMAINS ACROSS THE MID ATLANTIC THROUGH TONIGHT. A
WEAK COLD FRONT WILL TRACK ACROSS THE AREA SATURDAY MORNING. HIGH
PRESSURE WILL RETURN SUNDAY BEFORE UNSETTLED WEATHER EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
OVERALL A PRETTY QUIET EVENING OVER SE VA. HAVE SOME MID TO HIGH
LEVEL CLOUDS FROM NE NC THROUGH THE WESTERN SHORE OF THE CHES BAY
AND UP THE DELMARVA. THESE CLOUDS WILL CONTINUE TO SLIDE EWD
TONIGHT AS A COLD FRONT APPROACHES FROM THE NE. THE COLD FRONT AT
1Z STRETCHES FROM NR IPT TO KW99 TO JKL. THE FRONT WILL CONTINUE
TO SLIDE SE...BUT AHEAD OF IT...THE SKY WILL REMAIN CLEAR AS THE
FRONT IS AN ANAFRONT. ONCE THE FRONT PASSES...WILL SEE SOME MID
LEVEL CLOUD COVER MOVING THROUGH. THE LIFT BEHIND THE FRONT IS
WEAK SO NOT ANTICIPATING ANY SHOWERS WITH THE FRONT. SO HAVE TWEAK
THE SKY COVER TO SHOW THE CLEARING EXPECTED AHEAD OF THE FRONT.
HAVE ALSO TWEAKED THE OVERNIGHT LOWS...GIVING THE TEMPS A LITTLE
BOOST DUE TO THE CURRENT DEWPOINT READINGS AND EXPECTATION OF SOME
CONTINUED SRLY FLOW IN ADVANCE OF THE FRONT. DO NOT EXPECT THE
COOLER CONDITIONS BEHIND THE FRONT TO ARRIVE UNTIL LATER ON
SATURDAY SO SHOULD NOT SEE A BIG TEMP DROP IMMEDIATELY BEHIND THE
FRONT DUE TO THE CLOUDS THAT WILL ARRIVE.
PREV DISCUSSION...
A TOUCH MORE HUMID ACRS THE FA THIS AFTN AS COMPARED TO PAST FEW.
SFC HI PRES CONTS TO WEAKEN THROUGH THE EVE HRS...WHILE CDFNT
APPROACHES FM THE NW. SO FAR...LTL MOVEMENT (N) NOTED ON SCT SHRAS
OVR ECNTRL NC THIS AFTN...17Z/14 RUC KEEPS THOSE SHRAS GENLY FM
ALBEMARLE SND ON S...OTRW XPCG CLR-PCLDY WX E...AND P/MCLDY W.
PCPN CURRENTLY ASSOCIATED W/ THE CDFNT HAS CONTD TO
DIMINISH...APRS THAT HIGHEST PROB FOR ANY SHRAS AND MOST
WIDESPREAD CLDNS WILL RMN NNW OF THE FA THROUGH TNGT. CDFNT TO
PRESS INTO THE CNTRL PORTION OF FA BY 12Z/15. WILL HAVE POPS AOB
14% OVR THE FA OVRNGT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
CDFNT PRESSES S AND E OF THE FA DURG SAT MRNG...W/ ASSOCIATED
WINDSHIFT TO THE N AS SFC HI PRES BUILDS EWD INTO THE ERN LAKES
RGN. FM SAT NGT THROUGH SUN...S/W MOVG INTO THE LWR MS
VALLEY...AND IN COMBINATION W/ STALLED FNTL BNDRY ACRSS THE
CAROLINAS...THERE WILL BE INCRSD COVERAGE OF CLDNS AND RAINFALL
(FM THE SRN MTNS THROUGH THE TN VLY AND LWR MS VLY. BY SUN
AFTN/EVE...CLDNS AND PCPN MAY BRUSH FAR SSW AREAS OF FA...OTRW SFC
HI PRES RMNS OVR THE RGN...PROVIDING DRY/NR SEASONABLE CONDS.
HI PRES TO BECOME SITUATED OFF THE E CST SUN NGT THROUGH MON...W/
TROUGH ALOFT DIGGING THROUGH THE MIDWEST. AT THE SAME TIME...S/W
WILL BE MOVG E THROUGH THE LWR MS VLY/SE STATES. MDLS GENLY AGREE
W/ INCRSG LLVL/MOIST FLO INTO THE MDATLC STATES...ESP ON
MON...BRINGING A MDT/HI PROB FOR RAINFALL. HI CHCS FOR MON TO BE
CONFINED TO INTR SECTIONS OF FA.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MEDIUM RANGE PERIOD BEGINS WITH SOUTHERN STREAM SHORTWAVE TROUGH
LIFTING NORTHEAST OUT OF THE DEEP SOUTH TOWARDS THE REGION... JUST
AHEAD OF THE NRN STREAM TROUGH POISED TO MOVE ACROSS THE MOUNTAINS
THROUGH TUESDAY. THE MODELS CONTINUE TO HANDLE THE UPPER TROUGH
SIMILARLY, WITH LLVL S WINDS STREAMING MOISTURE-RICH GULF MOISTURE
INTO THE REGION MONDAY NIGHT AND TUESDAY. PROGGED PW AND OMEGA
FIELDS INDICATE THAT OVERRUNNING MOISTURE SHOULD BE STRONG ENOUGH
TO WARRANT 50-60 POP FOR MONDAY NIGHT AND TUESDAY. FRONT APPROACHES
THE REGION TUESDAY NIGHT, WITH THE FRONT LKLY TO CLEAR THE REGION
WEDNESDAY. LOW/MIDLVL FLOW BECOMES W/NW WITH RESULTANT DOWNSLOPE
FLOW SUFFICIENT TO BRING A DRY FORECAST FOR THE LATTER HALF OF THE
WEEK AHEAD.
FOR TEMPERATURES...EXPECT MAXIMA TO AVERAGE NEAR TO JUST BELOW CLIMO
NORMAL FOR THE PERIOD. HIGHS GENERALLY INTO THE 70S TO NR 80. LOWS
IN THE 60S TO NR 70 TUESDAY MORNING...FALLING BACK INTO THE 50S AND
60S TOWARDS THE MIDDLE OF NEXT WEEK, WITH SOME EARLY MORNING LOWS IN
THE UPPER 40S POSSIBLE TOWARDS LATE NEXT WEEK WEST OF RIC.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A WEAK COLD FRONT WILL APPROACH FROM THE THE NW AND MOVE THROUGH
THE TAF SITES BETWEEN 10-15Z LATER THIS MORNING. PATCHY FOG
SHOWING UP IN SOME OF THE AREA...BUT NOT AFFECTING TAF SITES AS OF
YET. IN GENERAL LOOKS LIKE LIGHT SSW FLOW AHEAD OF THE FRONT WILL
INHIBIT FOG FORMATION EARLY THIS MORNING...ALTHOUGH DECIDED TO ADD
A TEMPO GROUP AT KECG WHERE FRONT WILL BE DELAYED BY SEVERAL HRS
KEEPING NEAR CALM WINDS AND SLIGHTLY MORE MOIST AIRMASS IN PLACE
THROUGH 12Z.
OTHERWISE...NORTHERLY WINDS BECOME GUSTY TO 15-20 KT BETWEEN
12-18Z IN THE WAKE OF THE FRONT WITH GOOD MIXING. WINDS AND
GUSTINESS SLOWLY SUBSIDE THROUGH THE AFTN HRS AS HIGH PRESSURE
BUILDS IN FROM THE N. QUIET CONDITIONS PREVAIL TONIGHT/SUN.
SE FLOW WILL BRING INCREASING MOISTURE BY MON...WITH PERIODS OF PRECIP
AND LWR CIGS/VSBYS MON AFTN THROUGH TUE.
&&
.MARINE...
SSW FLOW PERSISTS EARLY THIS MORNING AHEAD OF A COLD FRONT. SEAS
RUNNING 2-3 FT NEAR SHORE (1-2FT BAY/SND). UPSTREAM OBS AND LATEST
MODEL DATA CONTINUE TO SUPPORT A COLD SURGE/SCA EVENT OVER THE
CHES BAY AND RIVERS LATER THIS MORNING INTO THE AFTN AND SCA HAS
BEEN HOISTED FOR SATURDAY OVER THE CHES BAY AND RIVERS. WINDS
DIMINISH WITH SLACKENING GRADIENT THIS AFTN AND EVENING. HOWEVER,
SEAS OVER WATERS LOOK TO REMAIN IN 3-4 FT RANGE DUE TO INCOMING
E-SE SWELL (15-20 SEC) ARRIVING ALONG THE MID- ATLANTIC COAST
BEGINNING THIS EVENING THROUGH SUNDAY FROM DISTANT TROP STORM
NADINE (WHICH IS ORIENTED WELL E/SE OF BERMUDA). THESE SWELLS WILL
ALSO LIKELY RESULT IN CONTINUED ELEVATED RIP THREAT THROUGH THE
WEEKEND.
N-NW WINDS CONTINUE TO DIMINISH SAT NIGHT/SUN AS SFC HIGH PRESSURE
SLIDES OVERHEAD. SFC RIDGE IS EXPECTED TO SLIDE OFF THE COAST LATER
SUN THRU MON. A WARM FRONT THEN LIFTS ACROSS THE AREA DURING MON/MON
NGT...WITH S-SE FLOW INCREASING TO 15 KT MON-TUE. TIGHTENING PRESSURE
GRADIENT MAY LEAD TO SCA CONDITIONS IN S/SE FLOW MON NGT/TUE/TUE
NGT (APPEARS LIKELY DUE TO 5 FT+ SEAS FOR COAST).
&&
.EQUIPMENT...
AT SBY...NORMAL ASOS COMMS REMAIN DOWN AND ARE EXPECTED TO STAY DOWN
FOR SEVERAL DAYS. OBS ARE BEING SENT BY THE TOWER BUT THESE UPDATES
MAY NOT BE RELIABLE SO AMD NOT SKED WILL CONTINUE TO APPEAR IN THE
TAFS.
COMMS WITH ORF ASOS HAVE BEEN RESTORED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EDT THIS
EVENING FOR ANZ630>632-634>638.
&&
$$
SYNOPSIS...ALB/SAM
NEAR TERM...ALB/ESS
SHORT TERM...ALB
LONG TERM...MAM
AVIATION...LKB
MARINE...LKB/MAM
EQUIPMENT...AKQ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
757 PM EDT SUN SEP 16 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A W FLOW ALF OVER
THE GRT LKS BTWN DEEPENING TROF IN SCNTRL CAN AND PROGRESSIVE SHRTWV
RDG MOVING THRU THE GRT LKS. THERE IS A WEAK SHRTWV EMBEDDED IN THIS
FLOW MOVING THRU WRN LK SUP EARLY THIS AFTN...BUT DRY AIRMASS
DOMINATING THE AREA AND SHOWN ON THE 12Z RAOBS IS LIMITING ANY
ACCOMPANYING WX TO JUST SOME PATCHY MID/HI CLDS. A STEADY WSW LLVL
FLOW BTWN SFC HI PRES MOVING INTO THE MID ATLANTIC STATES AND A LO
PRES TROF OVER THE KEWEENAW/WRN LK SUP ASSOCIATED WITH THE SHRTWV IS
BEGINNING TO DRAW MORE SFC-H9 MSTR SHOWN ON THE 12Z MPX RAOB TOWARD
THE AREA...BUT SFC DEWPTS HAVE MIXED OUT TO AS LO AS THE MID 40S AS
OF EARLY THIS AFTN OVER THE CWA IN ADVANCE OF THIS LLVL MOISTENING.
FARTHER TO THE NW...A SHARP COLD FNT STRETCHES FM NW ONTARIO ACRS MN
INTO SDAKOTA. DUE TO THE DRYNESS OF AIRMASS AHEAD OF THIS FNT...
THERE IS CURRENTLY NO SHRA AHEAD OF THIS BNDRY. BUT MORE CLDS/SOME
-SHRA ARE EVIDENT OVER NDAKOTA IN THE COLD AIR TRAILING THE FNT WITH
APRCH OF SHRTWVS EMBEDDED IN THE DEEPENING TROF OVER SCNTRL CAN AND
ACCOMPANYING DPVA/H7-3 QVECTOR CNVGC AS WELL AS UPR DVGC IN RRQ OF
ASSOCIATED H3 JET MAX NEAR LK WINNIPEG.
LATE THIS AFTN/EARLY EVNG...ISSUED WILDFIRE POTENTIAL STATEMENT
EARLIER IN THE SHIFT TO ACCOUNT FOR COMBINATION OF WELL ABV NORMAL
TEMPS...MIN RH FALLING TO 30-35 PCT...GUSTY WSW WINDS ENHANCED BY
DEEP MIXING...AND RECENT DRYNESS. THE MOST CRITICAL CONDITIONS ARE
OVER THE SCNTRL...WHERE SHARPER PRES GRADIENT/HIER WINDS ARE
EVIDENT. QUESTION IS WHETHER RETURNING LLVL MSTR SHOWN ON THE 12Z
MPX RAOB MIGHT CAUSE SOME CONVECTION ON INCOMING LO PRES TROF UNDER
SOME DPVA/H85-5 QVECTOR CNVGC ASSOCIATED WITH APRCHG SHRTWV. RECENT
GFS RUNS HAVE BEEN QUITE CONSISTENT SHOWING SOME CONVECTION. SINCE
THE 12Z RAPID REFRESH RUC MODEL...THE FINER RES CNDN MODEL...AND THE
NAM HINT SOME CONVECTION WL IMPACT MAINLY THE CNTRL ZNS WHERE LLVL
MOISTENING AND DYNAMICS COME INTO PHASE NEAR PEAK HEATING TIME...
MAINTAINED SCHC POPS OVER THE CNTRL DESPITE MID LVL DRYNESS THAT WL
LIMIT COVERAGE OF ANY ASSOCIATED SHRA/TS TO ISOLD.
TNGT...ANY INSTABILITY SHRA/TS WL DISSIPATE WITH LOSS OF DAYTIME
HEATING/ARRIVAL OF SOME DNVA/H85-5 QVECTOR DVGC IN THE WAKE OF
INITIAL SHRTWV PASSAGE. THEN COLD FNT ASSOCIATED WITH DEEPENING TROF
IN CANADA IS PROGGED TO PUSH ACRS THE W HALF OF UPR MI BY 12Z MON.
SINCE THE SHARPEST H7-3 QVECTOR CNVGC ASSOCIATED WITH SHRTWVS MOVING
THRU THE AMPLIFYING UPR TROF/UPR DVGC IN RRQ OF H3 JET MAX MOVING
INTO NW ONTARIO IS FCST TO FOLLOW THE FROPA...EXPECT THE BULK OF ANY
PCPN TO FALL ON THE COLD SIDE OF THE BNDRY...AS IS OBSVD TODAY IN
THE NRN PLAINS. GOING POPS INCRSG TOWARD CATEGORICAL OVER THE W
APPEAR PRETTY MUCH ON TRACK...BUT DID CUT POPS OVER THE E HALF WITH
AN ABSENCE OF UPR FORCING IN THAT AREA WITHIN DRIER AIRMASS AHEAD OF
THE FROPA.
MON...AREA OF SHRA/CATEGORICAL POPS OVER THE W HALF IN THE MRNG
SHOULD SPREAD INTO THE E AS UPR TROF AXIS SHIFTS SLOWLY TO THE E AND
AREA OF IMPRESSIVE H7-3 QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET TO
THE N SHIFTS TO THE E FOLLOWING SFC COLD FROPA. ALTHOUGH MODELS
INDICATE SOME MID LVL DRYING MIGHT IMPACT THE W IN THE AFTN...
ARRIVAL OF COLDER H85 AIR...WITH TEMPS AT THAT LVL FCST NEAR 0C OVER
THE W LATER IN THE DAY...IN CYC NLY FLOW TO W OF SFC LO THAT DVLPS
ON THE COLD FNT TO THE E SHOULD MAINTAIN LK ENHANCED SHOWERS IN THAT
AREA THRU 00Z TUE. ALTHOUGH TEMPS MIGHT WARM A BIT OVER THE E BEFORE
COLD FROPA/THICKER CLDS ARRIVE...READINGS ARE LIKELY TO FALL
FOLLOWING THE FROPA. SO NON-DIURNAL TEMP CURVE WITH STEADY/SLOWLY
FALLING TEMPS AT MOST PLACES IN THE AFTN APPEARS IN ORDER. DID
RETAIN A MENTION OF TS OVER THE E NEAR AND JUST BEHIND FROPA TIME AS
NAM FCST SDNGS HINT AT MUCAPE UP TO 500 J/KG. WITH A GUSTY N WIND...
SHRA... AND FALLING TEMPS THRU THE 50S...MON WL HAVE A DISTINCT
AUTUMNAL FEEL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
MAIN CONCERN IN THE MON NIGHT-WED TIME PERIOD CONTINUES TO BE
POPS...AND ALSO THE POSSIBILITY OF A HARD FREEZE TUESDAY NIGHT
ACROSS THE INTERIOR.
NO MAJOR CHANGES OF FORECAST THINKING FOR MONDAY NIGHT. THE UPPER
TROUGH GRADUALLY SETTLES ACROSS THE UPPER LAKES MONDAY
NIGHT...CENTERED OVER LAKE SUPERIOR BY TUESDAY MORNING. DESPITE THE
SURFACE LOW MOVING NE AND AWAY FROM THE REGION...A LAKE AGGREGATE
TROUGH WILL PERSIST ACROSS THE LAKE AS THE UPPER TROUGH MOVES
OVERHEAD. THIS WILL KEEP PBL WINDS PEGGED TO A NORTHERLY DIRECTION
ACROSS THE LAKE WHICH COMBINED WITH STEEPENING LOW LEVEL LAPSE RATES
AS THE 850MB TEMPS DROP TO -3C SHOULD FAVOR A FAIRLY PERSISTANT RAIN
ACROSS NORTH CENTRAL UPPER MICHIGAN MONDAY NIGHT. THERE ARE SOME
DIFFERENCES BETWEEN THE GFS AND NAM REGARDING THE EVOLUTION OF LOW
LEVEL WIND FLOW. THE GFS SUGGESTS THE WIND WILL BACK SLIGHTLY MONDAY
NIGHT OVER UPPER MI WHICH WOULD KEEP THE HEAVIEST PCPN JUST TO THE
EAST OF MARQUETTE. MEANWHILE...THE NAM WANTS TO KEEP THE WINDS A
LITTLE EAST OF NORTH...WHICH WOULD BE HIGHLY FAVORABLE FOR THE
HIGHER ELEVATIONS WEST OF MARQUETTE. WOULD NOT BE SURPRISED IF THE
GFS WIND VERIFIES...BUT IT MAY NOT MAKE A DIFFERENCE IN PCPN CHANCES
GIVEN THE LAKE ENHANCED NATURE OF THE PCPN VS. LAKE EFFECT. THE NAM
AND GFS ALSO SUGGEST THAT THE RAIN WILL DIMINISH MON NIGHT SOME OF
THE MID LEVEL MOISTURE BRIEFLY SCOURS OUT BEFORE A REINFORCING SHOT
OF MOISTURE MOVES IN BY TUE MORNING. ALTHOUGH THIS MAY HAPPEN...THE
FACT THAT THE LAKE INDUCED EQULIBRIUM LEVEL RISES TO OVER 20 KFT
OVERNIGHT MONDAY AND LARGE SCALE FORCING PERSISTS AS THE UPPER
TROUGH MOVES OVERHEAD SHOULD HELP TO OFFSET ANY MID LEVEL DRYING.
THE 4KM NAM NEST AND THE LOCAL WRF-ARW SUGGEST THE LAKE ENHANCED
PCPN WILL DEVELOP IN EARNEST AS SOON AS THE 850MB TEMPS DROP...SOON
AFTER 00Z. IN ADDITION...THE MORE LAKE ENHANCED NATURE OF THE PCPN
/VS LAKE EFFECT/ WOULD SUGGEST A MORE EVENLY DISTRUBUTED AREA OF
PCPN ACROSS ALL OF NORTH CENTRAL UPPER MI. WITH ALL OF THIS BEING
SAID...WILL KEEP CATEGORICAL POPS FOR MUCH OF NORTH CENTRAL UPPER
MICHIGAN CLOSER TO LAKE SUPERIOR...SIMILAR TO PREVIOUS FORECASTS. AS
FOR THE FAR EAST...PCPN MAY LIGHTEN UP MON NIGHT AS NORTHERLY PBL
FLOW NOT TERRRIBLY FAVORABLE FOR PCPN IN THAT AREA.
WITH THE UPPER TROUGH OVERHEAD ON TUESDAY...AND NEUTRAL TO SLIGHTLY
CYCLONIC PBL FLOW...WILL OPT TO MAINTAIN POPS AND RAISE THEM
SLIGHTLY TUESDAY NEAR LAKE SUPERIOR. AS THE TROUGH EXITS DURING THE
DAY...THE ASSOCIATED MID LVL FORCING WILL EXIT. THIS WILL ALLOW FOR
THE SURFACE RIDGING TO BUILD IN DURING THE DAY AND AS SUCH SHOULD
ALLOW FOR LAKE EFFECT PCPN TO GRADUALLY DIMINISH BY EVENING. AM NOT
IN TOO MUCH OF A HURRY TO END PCPN ON TUESDAY THOUGH...AS THE RIDGE
AXIS REALLY DOES NOT BUILD IN UNTIL AFTER 00Z WED. TEMPS WILL
STRUGGLE TO REACH 50 ACROSS THE INTERIOR DUE TO CLOUDS AND SHOWERS.
IN FACT...ALL NWP WANTS TO KEEP THE INTERIOR IN THE MID-UPPER 40S ON
TUESDAY. THIS SEEMS REASONABLE ESPECIALLY IF CLOUDS PERSIST...AND
HAVE THEREFORE LOWERED TEMPS ACROSS THE ENTIRE AREA ON
TUESDAY...WITH MOST INTERIOR SECTIONS STAYING IN THE 40S.
ANY REMAINING SHOWERS SHOULD END EARLY TUE EVENING...THEN THE RIDGE
BUILDS IN. THIS RIDGING COMBINED WITH PRECIPITABLE WATER VALUES AS
LOW AS 0.45 INCH SHOULD ALLOW FOR SKIES TO CLEAR OUT ACROSS THE
WEST. LAKE CLOUDS SHOULD HANG ON EAST...BUT EVEN THERE IT MAY CLEAR
OUT BY MORNING. REGARDLESS...WITH CLEAR SKIES AND LIGHT WINDS...IT
SHOULD GET COLD ACROSS THE INTERIOR. AM NOW THINKING A HARD FREEZE
IS IN STORE BY WED MORNING FOR THE INTERIOR WEST. EVEN THE RAW NAM
WHICH USUALLY HAS A WARM BIAS DURING RADIATIONAL COOLING HAS TEMPS
ACROSS IRON COUNTY IN THE 20S...AND THE GFS HAS 2M TEMPS IN THE
LOWER 30S. NAM MOS GUIDANCE SUGGEST SIMILAR TO COLDER TEMPS FOR TUE
NIGHT. WILL THEREFORE LOWER TEMPS ACROSS THE ENTIRE AREA TUE NIGHT.
SOME MODEL DIFFERENCES REGARDING THE NEXT SYSTEM. THE GFS IS MUCH
FASTER...UP TO 12 HRS...BRINIGING PCPN IN BY LUNCHTIME WED.
MEANWHILE...THE NAM AND GEM ARE MUCH SLOWER...NOT BRINGING IN PCPN
UNTIL WED EVENING. THE COMBINATION OF THE INCREASING WARM
ADVECTION/ISENTROPIC LIFT AND INCREASING MID LVL MOISTURE ACROSS THE
WEST WED AFTN IN THE NAM WOULD IMPLY AT LEAST A CHANCE FOR RAIN WED
AFTN DESPITE THE MODEL NOT PRINTING OUT MUCH QPF. WILL THEREFORE GO
WITH 30 PCPN CHANCE FOR SHOWERS WED AFTN FOR WESTERN UPPER MI. WILL
KEEP A DRY FCST FOR THE REMAINDER OF THE AREA.
IN THE EXTENDED /WED NIGHT-NEXT SUNDAY/...THE FULL AMPLITUDE LONG
WAVE TROUGH WILL PERSIST FROM HUDSON BAY THROUGH THE GREAT LAKES
REGION THROUGH THE PERIOD. THIS WILL KEEP THE WEATHER FAIRLY
UNSETTLED THROUGH SATURDAY. THE NUMERICAL GUIDANCE IS IN GOOD
AGREEMENT REGARDING THE LONG WAVE...BUT DIFFER SOMEWHAT ON SPECIFIC
DETAILS REGARDING INDIVIDUAL SHORT WAVES AND AS SUCH THEY DIFFER ON
EXACT POSITION OF THE LONG WAVE TROUGH. THE MAIN OUTLIER WITH THE
00Z RUN IS THE OPERATIONAL ECMWF WHICH KEEPS THE MAIN TROUGH
POSITIVLY TILTED WITH THE TROUGH AXIS FURTHER WEST. THIS IS LIKELY
DUE TO THAT MODEL ALLOWING STRONGER SHORT WAVE ENERGY TO DIVE DOWN
THE BACK SIDE OF THE UPPER TROUGH THURSDAY INTO FRIDAY. AT THIS
TIME...THIS IS NOT SUPPORTED BY THE GFS...NOR THE MAJORITY OF THE
ENSEMBLE MEMBERS FROM THE GFS AND ECMWF. WILL THEREFORE TREND THE
FORECAST TOWARD THE GFS/GEM COMPROMISE...BUT THE REALITY OF THE
MATTER IS THAT EITHER SOLUTION WOULD MAINTAIN UNSETTLED WEATHER FOR
THE AREA FOR MUCH OF THE EXTENDED. THERE WILL BE PERIODS OF DRY
WEATHER...BUT GIVEN THE UNCERTAINTY OF EXACT SHORT WAVE POSITIONS
ESPECIALLY FOR LATE INTO THE WEEK...IT WILL BE TOUGH TO PIN DOWN
SPECIFICS. WITH THAT BEING SAID...WILL NEED TO GO WITH CHANCE POPS
EACH DAY OF THE EXTENDED THROUGH SATURDAY. THE BEST CHANCE FOR RAIN
MAY BE FRIDAY INTO FRIDAY NIGHT WHERE THE GFS AND GEM BOTH AGREE ON
A WAVE MOVING ACROSS THE UPPER LAKES WITH LOW PRESSURE ACROSS THE
AREA. IN FACT...EVEN THE ECMWF SHOWS PCPN FRIDAY. BY SUNDAY...THE
GFS SUGGESTS THAT THE TROUGH WILL SLOWLY EXIT EAST OF THE
AREA...ALLOWING SOME DRYING TO MOVE IN. WILL THEREFORE GO WITH A DRY
FORECAST FOR NOW ON SUNDAY...BUT THAT IS SUBJECT TO CHANGE IF THE
TROUGH IS A LITTLE SLOWER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 756 PM EDT SUN SEP 16 2012
VFR CONDITIONS WILL PREVAIL THROUGH MUCH OF THE NIGHT...WITH
INCREASING CLOUDS EXPECTED BEHIND SURFACE COLD FRONT CURRENTLY
MOVING ACROSS UPPER MI. SHIELD OF PRECIP WILL FOLLOW INCREASING
CLOUDS BY EARLY MORNING HOURS. WITH ONSET OF MODERATE RAIN...EXPECT
CIGS AND VIS TO DROP TO IFR CONDITIONS AT KIWD AND KCMX...AND THEN
AT KSAW A FEW HOURS LATER. MAIN FORCING AND PRECIP SHOULD BEGIN
MOVING EASTWARD AWAY FROM KIWD AND KSAW BY LATE IN THE TAF PERIOD.
CONFIDENCE IS STILL NOT HIGH ON EXACT TIMINGS OR CIG/VIS
VALUES...BUT GENERAL TREND IS EXPECTED. WITH STRONG PRESSURE
GRADIENTS AND COOL NORTHERLY WINDS...WINDS WILL INCREASE DURING THE
DAY ALONG WITH RAIN SHOWERS. STRONGEST WINDS ARE EXPECTED AT KSAW AS
N WINDS FLOW OFF LAKE SUPERIOR TOWARDS THE TAF SITE. THIS IS ALSO A
GOOD SET UP FOR LAKE ENHANCED SHOWERS AT KSAW...SO WILL KEEP
MODERATE RAIN IN TAFS THROUGH REMAINDER OF TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT SUN SEP 16 2012
EXPECT RELATIVELY LIGHT WINDS UNDER 20 KTS FOR MOST OF THIS EVENING
OVER THE LAKE WITH FAIRLY HI STABILITY/A WEAK LO PRES TROF CROSSING
THE AREA. THEN EXPECT A WIND SHIFT TO THE NNW WITH THE PASSAGE OF A
STRONG COLD FRONT BY LATE EVENING OVER THE W AND THEN ON MON MORNING
OVER THE E HALF. AS COLDER AIR FOLLOWS THE FRONT OVER THE RELATIVELY
WARM WATERS OF LAKE SUPERIOR AND STABILITY DECREASES...EXPECT
STRONGER N WINDS TO 25 TO 30 KTS TO DEVELOP W TO E. BUT SINCE LATEST
GUIDANCE INDICATES THE PRES GRADIENT WILL BE WEAKER THAN EXPECTED ON
PREVIOUS SHIFTS...GALES NOW APPEAR UNLIKELY. SO THE GOING GALE WATCH
THAT WAS IN EFFECT ON MON OVER PORTIONS OF THE W HALF WAS DROPPED.
NORTH WINDS WILL PERSIST MONDAY NIGHT INTO TUESDAY BEFORE GRADUALLY
SHIFTING TO THE NW THEN W BY TUESDAY EVENING. ANOTHER LOW PRESSURE
TROUGH WILL APPROACH WED THEN PASS ACROSS THE LAKE WED NIGHT. AHEAD
OF THE TROUGH...WINDS WILL TURN SOUTHERLY AT 15-25 KT...THEN WILL
TURN W-NW BY THU MORNING. OTHER THAN SOME GUSTS CLOSE TO GALE FORCE
MONDAY EVENING...GALES ARE NOT EXPECTED AT THIS TIME THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MRD
AVIATION...JMW
MARINE...KC/MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
344 PM EDT SAT SEP 15 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 339 PM EDT SAT SEP 15 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A WNW FLOW ALF
OVER THE UPR GRT LKS TO THE W OF SLOWLY DEPARTING TROF IN QUEBEC AND
E OF MORE ZONAL FLOW OVER THE NRN ROCKIES. SFC HI PRES UNDER THE
CONFLUENT UPR FLOW IN THE GRT LKS IS CENTERED OVER SE ONTARIO JUST E
OF THE SAULT. SOME SC LINGERS OVER THE ERN CWA EARLY THIS AFTN IN
ASSOCIATION WITH DEPARTING H85 THERMAL TROF/LINGERING LLVL MSTR
SHOWN ON THE 12Z APX RAOB. BUT AS THE HI IS SHIFTING TO THE E...THE
SSW RETURN FLOW ON ITS WESTERN FLANK IS DRAWING WARMER/DRIER AIR
NOTED TO THE W BACK INTO THE UPR LKS. 12Z H85 TEMPS ARE AS HI AS 20C
AT BISMARCK. 12Z H85-7 DEWPT DEPRESSIONS ARE 20 TO 25C IN THE NRN
PLAINS...WHERE PWAT IS GENERALLY 0.25 TO 0.50 INCH...AS LITTLE AS 50
PCT OF NORMAL. MOISTER AIR AT H925-85 LURKS TO THE S IN KANSAS/
MISSOURI.
TONIGHT...AS THE HI TO THE E DRIFTS FARTHER AWAY UNDER WNW FLOW
ALF...THE LLVL WIND IS FCST TO SHIFT TO THE WSW IN ADVANCE OF LO
PRES TROF APRCHG FM THE W AHEAD OF SHRTWV EMBEDDED IN THE ZONAL FLOW
ALONG THE NDAKOTA/CNDN BORDER THIS MRNG. THIS FLOW IS PROGGED TO
ADVECT THE MUCH WARMER H85 AIR TO THE W THIS MRNG INTO THE UPR
LKS...WITH H85 TEMPS FCST TO RISE AS HI AS 16-18C AT IWD BY 12Z SUN.
ANY LINGERING LO CLDS OVER THE E SHOULD DISSIPATE EARLY WITH THE
ARRIVAL OF THIS WARMER AND DRIER AIR. ALTHOUGH THE AIRMASS IS
PROGGED TO REMAIN DRY THRU THE NGT...INCRSG H925 WINDS UP TO
30-35KTS LATE AS WELL AS THE ARRIVAL OF SOME PATCHY HI CLDS INDICATE
TNGT WL BE MUCH WARMER THAN THIS MRNG. EXPECT THE HIEST MIN TEMPS
OVER THE W AND NCNTRL NEAR LK SUP.
SUN...INCOMING LO PRES TROF IS PROGGED TO DRIFT INTO THE WRN CWA IN
THE AFTN AND INTERACT WITH H85 THERMAL RDG/AXIS OF H85 TEMPS IN THE
14-15C RANGE IN PLACE. ALTHOUGH MODELS INDICATE SW FLOW IN ADVANCE
OF THE TROF WL ADVECT MOISTER LLVL AIR IN KS/MO THIS MRNG INTO THE
UPR LKS...VERY DRY H85-7 AIR IN THE NRN PLAINS/ADJOINING SRN CAN AND
LACK OF SGNFT DYNAMIC FORCING TO ERODE MID LVL CAPPING/CAUSE H5
FALLS WL BE LIMITING FACTORS FOR PCPN. EVEN WITH THESE NEGATIVES...
SOME MODELS...ESPECIALLY THE CONSISTENT 12Z GFS...DO GENERATE SOME
PCPN OVER MAINLY THE NRN TIER COUNTIES ALONG AND AHEAD OF THE
INCOMING TROF. CONSIDERING THE NEGATIVES...OPTED TO FOLLOW THE DRIER
12Z NAM/LOCAL WRF-ARW MODELS AND MAINTAIN A PCPN-FREE FCST FOR MOST
OF THE CWA. DID RETAIN GOING SCHC POPS OVER WRN AND NCNTRL LK SUP
CLOSER TO MORE SUBSTANTIAL H5 FALLS ASSOCIATED WITH DEEPENING TROF
IN SCNTRL CAN. FCST STEEP H7-5 LAPSE RATES IN EXCESS OF 7C/KM
WARRANTS A MENTION OF TS IN THIS AREA DESPITE LIMITED MSTR.
MIXING TO H8 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS NEAR 80 OVER THE
INTERIOR SCNTRL AWAY FM MODERATION OFF LK MI. WITH MORE MID/HI CLDS
AND/OR THE ARRIVAL OF THE TROF/WSHFT TO THE W...TEMPS OVER THE W AND
NRN TIER WL BE LOWER. THE COMBINATION OF THE UNSEASONABLE WARMTH
OVER MAINLY THE SCNTRL...GUSTY WSW WINDS TO 25-30 MPH ENHANCED BY
THE DEEPER MIXING...AND MIN RH DIPPING TO ARND 30 PCT AS DEWPTS MIX
OUT INTO THE 45-50 RANGE DESPITE SLOW ARRIVAL OF MORE LLVL MSTR
LATER IN THE DAY WL LEAD TO AN ELEVATED RISK OF WILDFIRES...
ESPECIALLY OVER THE CNTRL AND E WHERE THE PRES GRADIENT WL REMAIN
SHARPEST THRU THE DAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 339 PM EDT SAT SEP 15 2012
THE MAIN FORECAST CONCERN FOR SUNDAY NIGHT AND MONDAY ARE POPS
ASSOCIATED WITH THE UPPER TROUGH AND COLD FRONT MOVING INTO THE
UPPER LAKES. SUNDAY NIGHT SHOULD START OUT QUIET DESPITE THE COLD
FRONT BEING OVER WESTERN LAKE SUPERIOR. MOISTURE IS VERY LIMITED
ALONG THE FRONT SUNDAY EVENING...AND DYNAMICS ARE LACKING DUE TO THE
UPPER JET STILL BEING WELL WEST OVER THE UPPER MIDWEST.
HOWEVER...THIS IS EXPECTED TO CHANGE LATER SUNDAY NIGHT INTO MONDAY
AS THE UPPER TROUGH SHARPENS AS A RESULT OF THE 110 KT UPPER JET
DIVING SOUTH FROM THE YUKON SUNDAY NIGHT. THIS WILL ALLOW THE
UPSTREAM THERMAL GRADIENT TO TIGHTEN AND ASSOCIATED FRONTOGENETIC
CIRCULATION TO STRENGTHEN LATE SUNDAY AND INTO MONDAY AS IT MOVES
INTO UPPER MICHIGAN. MEANWHILE...DEEPER PACIFIC ORIGIN MOISTURE WILL
MOVE ACROSS THE REGION /WITH PRECIPITABLE WATER VALUES GREATER THAN
1 INCH/ AS SURFACE LOW PRESSURE DEVELOPS ALONG THE FRONT IN RESPONSE
TO THE RIGHT ENTRANCE REGION OF THE JET MOVING OVERHEAD. THERE ARE
SOME DIFFERENCES BETWEEN THE GFS AND NAM WITH REGARDS TO THE
PLACEMENT OF THE LOW AND THE MOVEMENT OF THE COLD FRONT...WITH THE
GFS BEING SLOWER AND AS SUCH FURTHER WEST WITH THE LOW PRES
DEVELOPMENT COMPARED TO THE NAM. THE NAM TENDS TO AGREE MORE WITH
THE 00Z ECMWF AND ALSO HAS SOME SUPPORT FROM SREF MEMBERS.
INCREASING 850MB COLD ADVECTION WILL ALLOW FOR INCREASING LAKE
INDUCED INSTABILITY LATE MONDAY INTO MONDAY NIGHT ON N-NW PBL WINDS
ON THE NW SIDE OF THE LOW. ALL OF THIS SHOULD COMBINE TO GIVE A
PERIOD OF STEADY RAIN STARTING LATE SUNDAY NIGHT AND CONTINUING
THROUGH MONDAY...AND IN FACT CONTINUING INTO MONDAY NIGHT INTO
TUESDAY FOR AREAS NEAR LAKE SUPERIOR. WITH THE LAKE AND TERRAIN
ENHANCEMENT DUE TO NORTHERLY FLOW OFF THE LAKE...SOME AREAS CLOSE TO
LAKE SUPERIOR COULD SEE 1-1.5 INCHES OF RAIN LATE SUNDAY
NIGHT-TUESDAY MORNING.
AS SUCH...HAVE OPTED TO MAKE ONLY MINOR TWEAKS TO THE GOING
FORECAST FOR SUNDAY NIGHT INTO TUESDAY. DUE TO THE EXTREMELY DRY
AIRMASS ALONG AND AHEAD OF THE FRONT...HAVE OPTED TO BACK OFF POPS
ESPECIALLY SUNDAY EVENING. ALTHOUGH IT MAY TAKE A LITTLE TIME FOR
THE FAR EAST TO SEE STEADY RAIN ON MONDAY DUE TO THE LOW PRESSURE
DEVELOPMENT ALONG THE FRONT KEEPING THAT AREA IN THE WARM SECTOR A
LITTLE LONGER...THE EXPECTATION IS THAT THE ENTIRE AREA WILL
EVENTUALLY SEE RAIN MONDAY. WILL THEREFORE GO WITH CATEGORICAL POPS
FOR THE ENTIRE FORECAST AREA ON MONDAY BUT WILL GO WITH THE HIGHEST
POPS ACROSS NORTH CENTRAL AND WESTERN UPPER MICHIGAN DUE TO THE
EVENTUAL LAKE/TERRAIN ENHANCEMENT DURING THE AFTERNOON. WILL
CONTINUE WITH CATEGORICAL POPS NEAR LAKE SUPERIOR ON MONDAY NIGHT
WITH NORTHERLY FLOW AND 850MB TEMPS DROPPING TO -3C...ALLOWING FOR
LAKE INDUCED EQUILIBRIUM LEVELS ABOVE 20KFT. WOULD NOT BE SHOCKED IF
THERE ARE SOME LIGHTNING STRIKES MONDAY NIGHT ESPECIALLY WITH THE
UPPER TROUGH OVERHEAD.
ALTHOUGH N-NW FLOW CONTINUES INTO TUESDAY...THE PBL FLOW BECOMES
NEUTRAL OR EVEN ANTI-CYCLONIC AS THE DAY GOES ON. IN ADDITION...THE
DEEP MOISTURE SHOULD BE SCOURED OUT AND THE BEST Q-VECT CONVERGENCE
MOVES EAST. DUE TO THE MODERATE LAKE INSTABILITY FROM 850MB TEMPS
AROUND -3C COMBINED WITH ONSHORE FLOW...CANNOT REMOVE POPS NEAR THE
LAKE...BUT WILL CONTINUE WITH SCATTERED POPS. BY TUESDAY
EVENING...IT SHOULD START TO CLEAR OUT AS THE UPR TROUGH MOVES EAST
AND THE SFC HIGH MOVES OVERHEAD. ALTHOUGH THE 12Z GFS IS QUITE
PROGRESSIVE IN MOVING THE HIGH TO THE EAST TUE NIGHT...THE GEM AND
ECMWF ARE CONSISTENT IN SHOWING A SLOWER AND LESS PROGRESSIVE SOLN.
WITH THE HIGH BEING OVERHEAD...IT LOOKS LIKE A GOOD RADIATIONAL
COOLING NIGHT ESPECIALLY ACROSS THE INTERIOR WEST AWAY FROM ANY
REMAINING LAKE CLOUDS...SO AREAS OF FROST ARE EXPECTED...IF NOT A
HARD FREEZE.
TEMPS FOR MONDAY/TUESDAY WILL REMAIN BELOW NORMAL...ALTHOUGH MONDAY
WILL BE WARMER THAN TUESDAY...ESPECIALLY ACROSS THE EAST. WITH 850MB
TEMPS AROUND -3C ON TUESDAY AND BLUSTERY N-NW FLOW...EXPECT TEMPS TO
STRUGGLE TO REACH 50...ESPECIALLY WHERE IT STAYS CLOUDY FOR MUCH OF
THE DAY NEAR LAKE SUPERIOR.
IN THE EXTENDED /WED-NEXT SATURDAY/...IT CERTAINLY LOOKS LIKE A
AUTUMN PATTERN ACROSS THE GREAT LAKES AS THE PATTERN WILL BE
DOMINATED BY AN INTENSIFYING LONGITUDINAL TROUGH ACROSS CENTRAL
CANADA AND EXTENDING SOUTHWARD INTO THE GREAT LAKES REGION BY THE
END OF THE WEEK. THIS WILL ALLOW FOR THE UNSETTLED AND COOL
WEATHER TO CONTINUE. AS FOR THE SPECIFICS...THE FIRST UPPER LOW THAT
WILL PLAGUE THE AREA EARLY IN THE WEEK WILL EJECT OUT TUE NIGHT/WED
IN RESPONSE TO ANOTHER SHORTWAVE DIVING DOWN THE BACK SIDE OF THE
LONG WAVE TROUGH. THIS SHOULD ALLOW FOR BRIEF RIDGING TO BUILD
ACROSS THE UPPER GREAT LAKES WED BEFORE THE NEXT SYSTEM MOVES IN AND
CLOSES OFF OVER THE GREAT LAKES BY FRI. AS SUCH...WILL CONTINUE WITH
CHANCE POPS FOR THE ENTIRE AREA THURSDAY. AS THE EVENT BECOMES A
LITTLE CLEARER IN THE NEXT FEW DAYS...POPS WILL LIKELY NEED TO BE
INCREASED IN THE FRIDAY/SATURDAY TIME PERIOD AS IT WILL BE COLD
ENOUGH ALOFT FOR LAKE ENHANCEMENT AND MOST OF THE NAEFS MEMBERS ALL
HAVE RAIN ON FRIDAY INTO SATURDAY. THE UPPER LOW SETTLES OVER THE
GREAT LAKES ON SATURDAY...ALTHOUGH THE ECMWF POSITION IS SOUTH OF
THE GFS POSITION. REGARDLESS...SATURDAY LOOKS UNSETTLED AND RATHER
WET. TEMPS THROUGH THE EXTENDED PERIOD WILL BE BELOW NORMAL. FRIDAY
AND ESPECIALLY SATURDAY COULD STRUGGLE TO GET OUT OF THE UPPER 40S
IF IT STAYS CLOUDY AND RAINY FOR THE ENTIRE DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 124 PM EDT SAT SEP 15 2012
EXPECT VFR CONDITIONS TO PREVAIL THIS FCST PERIOD AT ALL 3 SITES
WITH DRY AIRMASS ASSOCIATED WITH HI PRES IN SE CANADA DOMINATING.
TIGHTENING PRES GRADIENT BTWN THE DEPARTING HI PRES AND A COLD FRONT
MOVING ACROSS THE NRN PLAINS WILL LEAD TO LLWS TONIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 339 PM EDT SAT SEP 15 2012
EXPECT ESE WINDS UP TO 20 KTS THIS AFTERNOON TO VEER TO THE WSW
TONIGHT INTO SUN AS HI PRES IN SE ONTARIO RETREATS TO THE E AND A LO
PRES TROF APPROACHES FROM THE NW.
LOW PRESSURE WILL DEVELOP ALONG A COLD FRONT MOVING ACROSS THE UPPER
LAKES ON MONDAY. IT WILL DEEPEN AT IT MOVES JUST EAST OF LAKE
SUPERIOR ON MONDAY. THE TIGHTENING PRESSURE GRADIENT COMBINED WITH
INCREASING LAKE INSTABILITY WILL ALLOW FOR GALE FORCE NORTHERLY
WINDS ACROSS CENTRAL LAKE SUPERIOR MONDAY AND THEN ACROSS THE EAST
HALF OF LAKE SUPERIOR MONDAY NIGHT. HIGH PRESSURE BUILDS IN TUESDAY
NIGHT BEFORE A BROAD AREA OF LOW PRESSURE MOVES SOUTH THU AND
FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
LSZ267.
GALE WATCH FROM MONDAY EVENING THROUGH LATE MONDAY NIGHT FOR
LSZ266.
GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ264.
GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MRD
AVIATION...KC
MARINE...KC/MRD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
139 PM EDT SAT SEP 15 2012
.SYNOPSIS...
ISSUED AT 341 AM EDT SAT SEP 15 2012
OUTSTANDING WEATHER IS EXPECTED THIS WEEKEND AS HIGH PRESSURE SLIDES
ACROSS THE GREAT LAKES. THE NEXT COLD FRONT WILL MOVE THROUGH ON
MONDAY...BRINGING THE NEXT CHANCE OF RAIN. LAKE EFFECT RAIN SHOWERS
MAY DEVELOP TUESDAY...AS MUCH COOLER AIR INVADES THE REGION.
&&
.UPDATE...
ISSUED AT 139 PM EDT SAT SEP 15 2012
SCATTERED-BROKEN AREA OF CU/SC ACROSS MUCH OF NORTHERN LOWER AT
EARLY AFTERNOON...MOSTLY SUNNY ACROSS EASTERN UPPER AND FAR
NORTHEAST LOWER (WHILE A LITTLE COOLER ALOFT FARTHER NORTH IT IS
DRIER IN THE LOW LEVELS WITH DEW POINTS IN THE 35-40F RANGE). NO
BIG CHANGES TO THE FORECAST...JUST TWEAKS TO ACCOUNT FOR CURRENT
TRENDS.
UPDATE ISSUED AT 1052 AM EDT SAT SEP 15 2012
HIGH PRESSURE CENTERED RIGHT OVER MICHIGAN THIS MORNING. SOME
EARLY HIGHER ELEVATION FOG/STRATUS HAS BEEN THINNING...WITH
DIURNAL CU DEVELOPMENT EXPECTED BY MIDDAY. LIGHT WINDS TODAY WITH
LAKE BREEZES BEING FAIRLY UBIQUITOUS...AFTERNOON HIGHS MOSTLY IN
THE 60S/NEAR 70S ACROSS PARTS OF NORTHWEST LOWER.
UPDATE ISSUED AT 640 AM EDT SAT SEP 15 2012
BROKEN LAKE CLOUDS CONTINUE TO ROLL IN OFF LAKES MICHIGAN AND
HURON WITHIN A DRYING NORTHERLY FLOW. THESE CLOUDS ARE RATHER
THIN...AND DO NOT EXPECTED THEM TO LAST TOO MUCH AFTER SUNRISE
DUE TO MIXING INTO DRIER AIR. STILL LOOKING FOR A GOOD DEAL OF
SUNSHINE TODAY WITH LIGHT WINDS/AFTERNOON LAKE BREEZES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 341 AM EDT SAT SEP 15 2012
SHARP UPPER TROUGH WORKING INTO NEW ENGLAND WITH A SOLID NW FLOW
ALOFT OVER NRN MICHIGAN. ATMOSPHERIC SUBSIDENCE WITH DRY AIR
ADVECTION WITHIN ADVANCING SFC HIGH PRESSURE. STILL...VERY GOOD
OVERLAKE INSTABILITY HAS LED TO THE DEVELOPMENT OF STRATO CU IN
BACKING NW-W 1000-850MB FLOW...ATTACHED TO GREEN BAY. WINDS ARE
WEAKENING WITH TIME...SO FETCH AND INLAND PENETRATION WILL
CONTINUE LEAD TO LESS CLOUD...BUT THIS MAY TAKE THROUGH EARLY
DAYBREAK...WHEN MIXING INTO DRIER AIR ALOFT CAN HELP MIX IT ALL
OUT. TEMPERATURES WERE QUITE CHILLY...DIPPING INTO THE 30S IN
SEVERAL LOCALES OF NRN LOWER. SKIES WERE FAIRLY CLEAR ACROSS
EASTERN UPPER...WITH LATEST RUC ANALYSIS SUGGESTING A WEAKER WIND
FLOW AND LESS MOISTURE FLUX OFF WHITEFISH BAY/EASTERN LAKE
SUPERIOR. CANNOT RULE OUT SOME STRATO CU INTO CHIPPEWA COUNTY
THOUGH OVER THE NEXT FEW HOURS.
TODAY AND TONIGHT...VERY QUIET. SFC HIGH PRESSURE WILL MOVE IN
OVERHEAD WITH SOME SCATTERED CUMULUS DEVELOPMENT...MAINLY ALONG
THE AXIS OF THE SFC HIGH...AND AREAS EAST. THIS BRINGS THE BETTER
CU ACROSS NE LOWER AND EASTERN CHIP/MACK. BY LATER THIS
AFTERNOON...SOME LAKE BREEZES WILL TRY TO CONSOLIDATE THIS CLOUD
MORE INLAND. THE CLOUDS WILL QUICKLY ERODE TO CLEAR SKIES IN THE
EVENING WITH ONLY SOME SCATTERED MID CLOUD POSSIBLE OVERNIGHT.
THIS WILL BE AHEAD OF A WEAK SHORTWAVE AND LOW LEVEL WARM FRONT
LIFTING OUR WAY. A 30-35KT WSW ORIENTED LLJ COULD THEORETICALLY
RESULT IN SOME THIN CLOUDINESS LATE. WOULD HEDGE MY BETS ON A
FAIRLY CLEAR EVENING THOUGH. LOW TEMPS LIKELY IN THE LOW TO MID
40S WEST/NW CWA IN BETTER SW FLOW DEVELOPING...WITH THE COLDEST
MID TO UPPER 30S IN LOW LYING AREAS OF THE EASTERN CWA OF NRN
LOWER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 341 AM EDT SAT SEP 15 2012
HIGH PRESSURE AT THE SURFACE AND ALOFT SUNDAY IS EXPECTED TO LEAD TO
VERY PLEASANT WEATHER FOR THE LAST SUNDAY OF SUMMER (THE AUTUMNAL
EQUINOX IS EARLY SATURDAY MORNING ON SEPTEMBER 22ND). A COLD FRONT
WILL THEN MOVE ACROSS THE REGION LATER MONDAY SETTING THE STAGE FOR
LONG WAVE TROUGHING TO SETTLE INTO THE REGION FOR MUCH OF NEXT WEEK.
THIS WILL LEAD TO AN EXTENDED PERIOD OF COOLER AND UNSETTLED
WEATHER. THE MAIN LONG TERM FORECAST CONCERNS REVOLVE AROUND POPS
FOR ALL OF NEXT WEEK.
SUNDAY...SURFACE HIGH PRESSURE SHIFTS OFF TO OUR EAST WHILE UPPER
LEVEL HEIGHTS MAX/FLATTEN OUT. THIS IS EXPECTED TO LEAD TO LOTS OF
SUNSHINE AND MILD TEMPERATURES WITH HIGHS RANGING FROM THE MIDDLE
70S TO LOWER 80S.
SUNDAY NIGHT INTO MONDAY NIGHT...PARTLY CLOUDY SKIES WITH MILDER
TEMPERATURES SUNDAY NIGHT AS SOUTHWEST WINDS STAY UP A BIT. A COLD
FRONT MOVES ACROSS THE REGION LATER MONDAY LIKELY BRINGING SHOWERS.
LOWS SUNDAY NIGHT IN THE 50S WITH HIGHS ON MONDAY RANGING FROM THE
MIDDLE AND UPPER 60S NORTH TO THE MIDDLE AND UPPER 70S SOUTHEAST.
LOWS MONDAY NIGHT IN THE MIDDLE 40S TO LOWER 50S.
TUESDAY...HEIGHTS CONTINUE TO FALL AND COMBINE WITH INCREASING OVER
LAKE INSTABILITY (AS 850 MB TEMPERATURES FALL TO BETWEEN ZERO AND -2
C) AND A SHORT WAVE MOVING THROUGH THE FLOW TO PRODUCE A CHANCE OF
RAIN SHOWERS. THE MEAN FLOW APPEARS TO BE NORTH OR NORTH NORTHWEST
SO LOCALS NEAR THE LAKE SHORES WILL LIKELY HAVE THE BEST SHOT OF
RAIN. HIGHS RANGING FROM THE MUCH COOLER LOWER 50S NORTH TO AROUND
60 SOUTHEAST.
TUESDAY NIGHT...A WEDGE OF DRIER AIR IN COMBINATION WITH HIGH
PRESSURE NOSING IN FROM THE NORTH WILL SET THE STAGE FOR A VERY
CHILLY NIGHT. IF WINDS DECOUPLE...AND RIGHT NOW IT LOOKS LIKE THEY
WILL...THIS COULD LEAD TO THE FIRST SIGNIFICANT FROST OR FREEZE OF
THE SEASON.
WEDNESDAY THROUGH FRIDAY...ENERGY RIDING SOUTHEAST ON THE BACKSIDE
OF A BLOSSOMING PACIFIC RIDGE AMPLIFIES THE LONG WAVE TROUGH ACROSS
THE GREAT LAKES. SO THIS IN COMBINATION WITH PERIODIC SHORT WAVES
MOVING THROUGH THE FLOW AND INCREASING OVER LAKE INSTABILITY BRINGS
MORE CHANCES FOR RAIN SHOWERS. THE DETAILS OF WHICH WILL NEED TO BE
WORKED OUT BY FUTURE SHIFTS. HIGHS GENERALLY RANGING FROM THE MIDDLE
50S TO THE MIDDLE 60S. LOWS IN THE UPPER 30S AND 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 139 PM EDT SAT SEP 15 2012
VFR CONDITIONS EXPECTED THROUGH SUNDAY MORNING. AS GRADIENT
INCREASES TONIGHT SOME LOW LEVEL WIND SHEAR MAY BECOME AN ISSUE
(FOR NOW ONLY CARRIED IN TVC TERMINAL FORECAST).
&&
.MARINE...
ISSUED AT 159 AM EDT SAT SEP 15 2012
DROPPED SMALL CRAFT ADVISORY ACROSS THE NE LOWER NEARSHORE WATERS
UNDER A WEAKENING LOW LEVEL WIND FIELD...WITH SUPPORT FROM LATEST
MARINE OBS. THIS DESPITE GOOD OVERLAKE INSTABILITY...BUT GUSTY
WINDS ARE LIKELY...ESPECIALLY OVER LAKE HURON. HIGH PRESSURE WILL
THEN SETTLE INTO THE REGION TODAY FOR ONSHORE LAKE BREEZES IN THE
AFTERNOON. THIS HIGH EXITS EAST TONIGHT WITH SOUTHERLY WINDS
RETURNING. THERE IS AN OUTSIDE CHANCE AT SOME LOW END ADVISORY
LEVEL WINDS IN COASTAL CONVERGENCE REGIONS FROM MANISTEE THROUGH
THE MANITOU ISLANDS. CONFIDENCE IS LOW AT THIS POINT...ESPECIALLY
WITH LOW LEVEL WARMING AND INCREASING STABILITY. THESE SAME
ADVISORY POSSIBILITIES CONTINUE THROUGH SUNDAY NIGHT IN ADVANCE OF
THE NEXT LOW PRESSURE AND COLD FRONT WHICH PASSES MONDAY.
INSTABILITY OVER THE LAKES INCREASES RELATIVELY SUBSTANTIALLY
BEHIND THIS FRONT FOR WHAT COULD VERY WELL TURN OUT TO BE THE
BETTER CHANCES FOR ADVISORIES. UNSTABLE CONDITIONS ARE EXPECTED TO
HOLD FROM MONDAY NIGHT ALL THE WAY THROUGH NEXT WORK WEEK AND
POSSIBLY NEXT WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JPB
SYNOPSIS...AJS
SHORT TERM...SMD
LONG TERM...AJS
AVIATION...JPB
MARINE...SMD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1053 AM EDT SAT SEP 15 2012
.SYNOPSIS...
ISSUED AT 341 AM EDT SAT SEP 15 2012
OUTSTANDING WEATHER IS EXPECTED THIS WEEKEND AS HIGH PRESSURE SLIDES
ACROSS THE GREAT LAKES. THE NEXT COLD FRONT WILL MOVE THROUGH ON
MONDAY...BRINGING THE NEXT CHANCE OF RAIN. LAKE EFFECT RAIN SHOWERS
MAY DEVELOP TUESDAY...AS MUCH COOLER AIR INVADES THE REGION.
&&
.UPDATE...
ISSUED AT 1052 AM EDT SAT SEP 15 2012
HIGH PRESSURE CENTERED RIGHT OVER MICHIGAN THIS MORNING. SOME
EARLY HIGHER ELEVATION FOG/STRATUS HAS BEEN THINNING...WITH
DIURNAL CU DEVELOPMENT EXPECTED BY MIDDAY. LIGHT WINDS TODAY WITH
LAKE BREEZES BEING FAIRLY UBIQUITOUS...AFTERNOON HIGHS MOSTLY IN
THE 60S/NEAR 70S ACROSS PARTS OF NORTHWEST LOWER.
UPDATE ISSUED AT 640 AM EDT SAT SEP 15 2012
BROKEN LAKE CLOUDS CONTINUE TO ROLL IN OFF LAKES MICHIGAN AND
HURON WITHIN A DRYING NORTHERLY FLOW. THESE CLOUDS ARE RATHER
THIN...AND DO NOT EXPECTED THEM TO LAST TOO MUCH AFTER SUNRISE
DUE TO MIXING INTO DRIER AIR. STILL LOOKING FOR A GOOD DEAL OF
SUNSHINE TODAY WITH LIGHT WINDS/AFTERNOON LAKE BREEZES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 341 AM EDT SAT SEP 15 2012
SHARP UPPER TROUGH WORKING INTO NEW ENGLAND WITH A SOLID NW FLOW
ALOFT OVER NRN MICHIGAN. ATMOSPHERIC SUBSIDENCE WITH DRY AIR
ADVECTION WITHIN ADVANCING SFC HIGH PRESSURE. STILL...VERY GOOD
OVERLAKE INSTABILITY HAS LED TO THE DEVELOPMENT OF STRATO CU IN
BACKING NW-W 1000-850MB FLOW...ATTACHED TO GREEN BAY. WINDS ARE
WEAKENING WITH TIME...SO FETCH AND INLAND PENETRATION WILL
CONTINUE LEAD TO LESS CLOUD...BUT THIS MAY TAKE THROUGH EARLY
DAYBREAK...WHEN MIXING INTO DRIER AIR ALOFT CAN HELP MIX IT ALL
OUT. TEMPERATURES WERE QUITE CHILLY...DIPPING INTO THE 30S IN
SEVERAL LOCALES OF NRN LOWER. SKIES WERE FAIRLY CLEAR ACROSS
EASTERN UPPER...WITH LATEST RUC ANALYSIS SUGGESTING A WEAKER WIND
FLOW AND LESS MOISTURE FLUX OFF WHITEFISH BAY/EASTERN LAKE
SUPERIOR. CANNOT RULE OUT SOME STRATO CU INTO CHIPPEWA COUNTY
THOUGH OVER THE NEXT FEW HOURS.
TODAY AND TONIGHT...VERY QUIET. SFC HIGH PRESSURE WILL MOVE IN
OVERHEAD WITH SOME SCATTERED CUMULUS DEVELOPMENT...MAINLY ALONG
THE AXIS OF THE SFC HIGH...AND AREAS EAST. THIS BRINGS THE BETTER
CU ACROSS NE LOWER AND EASTERN CHIP/MACK. BY LATER THIS
AFTERNOON...SOME LAKE BREEZES WILL TRY TO CONSOLIDATE THIS CLOUD
MORE INLAND. THE CLOUDS WILL QUICKLY ERODE TO CLEAR SKIES IN THE
EVENING WITH ONLY SOME SCATTERED MID CLOUD POSSIBLE OVERNIGHT.
THIS WILL BE AHEAD OF A WEAK SHORTWAVE AND LOW LEVEL WARM FRONT
LIFTING OUR WAY. A 30-35KT WSW ORIENTED LLJ COULD THEORETICALLY
RESULT IN SOME THIN CLOUDINESS LATE. WOULD HEDGE MY BETS ON A
FAIRLY CLEAR EVENING THOUGH. LOW TEMPS LIKELY IN THE LOW TO MID
40S WEST/NW CWA IN BETTER SW FLOW DEVELOPING...WITH THE COLDEST
MID TO UPPER 30S IN LOW LYING AREAS OF THE EASTERN CWA OF NRN
LOWER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 341 AM EDT SAT SEP 15 2012
HIGH PRESSURE AT THE SURFACE AND ALOFT SUNDAY IS EXPECTED TO LEAD TO
VERY PLEASANT WEATHER FOR THE LAST SUNDAY OF SUMMER (THE AUTUMNAL
EQUINOX IS EARLY SATURDAY MORNING ON SEPTEMBER 22ND). A COLD FRONT
WILL THEN MOVE ACROSS THE REGION LATER MONDAY SETTING THE STAGE FOR
LONG WAVE TROUGHING TO SETTLE INTO THE REGION FOR MUCH OF NEXT WEEK.
THIS WILL LEAD TO AN EXTENDED PERIOD OF COOLER AND UNSETTLED
WEATHER. THE MAIN LONG TERM FORECAST CONCERNS REVOLVE AROUND POPS
FOR ALL OF NEXT WEEK.
SUNDAY...SURFACE HIGH PRESSURE SHIFTS OFF TO OUR EAST WHILE UPPER
LEVEL HEIGHTS MAX/FLATTEN OUT. THIS IS EXPECTED TO LEAD TO LOTS OF
SUNSHINE AND MILD TEMPERATURES WITH HIGHS RANGING FROM THE MIDDLE
70S TO LOWER 80S.
SUNDAY NIGHT INTO MONDAY NIGHT...PARTLY CLOUDY SKIES WITH MILDER
TEMPERATURES SUNDAY NIGHT AS SOUTHWEST WINDS STAY UP A BIT. A COLD
FRONT MOVES ACROSS THE REGION LATER MONDAY LIKELY BRINGING SHOWERS.
LOWS SUNDAY NIGHT IN THE 50S WITH HIGHS ON MONDAY RANGING FROM THE
MIDDLE AND UPPER 60S NORTH TO THE MIDDLE AND UPPER 70S SOUTHEAST.
LOWS MONDAY NIGHT IN THE MIDDLE 40S TO LOWER 50S.
TUESDAY...HEIGHTS CONTINUE TO FALL AND COMBINE WITH INCREASING OVER
LAKE INSTABILITY (AS 850 MB TEMPERATURES FALL TO BETWEEN ZERO AND -2
C) AND A SHORT WAVE MOVING THROUGH THE FLOW TO PRODUCE A CHANCE OF
RAIN SHOWERS. THE MEAN FLOW APPEARS TO BE NORTH OR NORTH NORTHWEST
SO LOCALS NEAR THE LAKE SHORES WILL LIKELY HAVE THE BEST SHOT OF
RAIN. HIGHS RANGING FROM THE MUCH COOLER LOWER 50S NORTH TO AROUND
60 SOUTHEAST.
TUESDAY NIGHT...A WEDGE OF DRIER AIR IN COMBINATION WITH HIGH
PRESSURE NOSING IN FROM THE NORTH WILL SET THE STAGE FOR A VERY
CHILLY NIGHT. IF WINDS DECOUPLE...AND RIGHT NOW IT LOOKS LIKE THEY
WILL...THIS COULD LEAD TO THE FIRST SIGNIFICANT FROST OR FREEZE OF
THE SEASON.
WEDNESDAY THROUGH FRIDAY...ENERGY RIDING SOUTHEAST ON THE BACKSIDE
OF A BLOSSOMING PACIFIC RIDGE AMPLIFIES THE LONG WAVE TROUGH ACROSS
THE GREAT LAKES. SO THIS IN COMBINATION WITH PERIODIC SHORT WAVES
MOVING THROUGH THE FLOW AND INCREASING OVER LAKE INSTABILITY BRINGS
MORE CHANCES FOR RAIN SHOWERS. THE DETAILS OF WHICH WILL NEED TO BE
WORKED OUT BY FUTURE SHIFTS. HIGHS GENERALLY RANGING FROM THE MIDDLE
50S TO THE MIDDLE 60S. LOWS IN THE UPPER 30S AND 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 640 AM EDT SAT SEP 15 2012
LOW LEVEL BKN MVFR LAKE CLOUDS WILL CONTINUE TO AFFECT THE
TVC/PLN/APN AREAS THROUGH AN HOUR OR TWO AFTER SUNRISE...AND WILL
BE HANDLED BY A TEMPO GROUP. HIGH PRESSURE STILL SETTLES IN FOR
TODAY AND TONIGHT...AND MIXING INTO DRIER AIR WILL RESULT IN JUST
SOME SCATTERED CU THIS AFTERNOON. THESE CLOUDS WILL LIKELY DEPART
THE AIRPORTS BY LATE AFTERNOON DUE TO LAKE BREEZE DEVELOPMENT. CALM
WINDS TONIGHT WITH ONLY THE CHANCE FOR SCATTERED LOW TO MID
CLOUDS. MAINLY CLEAR THOUGH.
&&
.MARINE...
ISSUED AT 159 AM EDT SAT SEP 15 2012
DROPPED SMALL CRAFT ADVISORY ACROSS THE NE LOWER NEARSHORE WATERS
UNDER A WEAKENING LOW LEVEL WIND FIELD...WITH SUPPORT FROM LATEST
MARINE OBS. THIS DESPITE GOOD OVERLAKE INSTABILITY...BUT GUSTY
WINDS ARE LIKELY...ESPECIALLY OVER LAKE HURON. HIGH PRESSURE WILL
THEN SETTLE INTO THE REGION TODAY FOR ONSHORE LAKE BREEZES IN THE
AFTERNOON. THIS HIGH EXITS EAST TONIGHT WITH SOUTHERLY WINDS
RETURNING. THERE IS AN OUTSIDE CHANCE AT SOME LOW END ADVISORY
LEVEL WINDS IN COASTAL CONVERGENCE REGIONS FROM MANISTEE THROUGH
THE MANITOU ISLANDS. CONFIDENCE IS LOW AT THIS POINT...ESPECIALLY
WITH LOW LEVEL WARMING AND INCREASING STABILITY. THESE SAME
ADVISORY POSSIBILITIES CONTINUE THROUGH SUNDAY NIGHT IN ADVANCE OF
THE NEXT LOW PRESSURE AND COLD FRONT WHICH PASSES MONDAY.
INSTABILITY OVER THE LAKES INCREASES RELATIVELY SUBSTANTIALLY
BEHIND THIS FRONT FOR WHAT COULD VERY WELL TURN OUT TO BE THE
BETTER CHANCES FOR ADVISORIES. UNSTABLE CONDITIONS ARE EXPECTED TO
HOLD FROM MONDAY NIGHT ALL THE WAY THROUGH NEXT WORK WEEK AND
POSSIBLY NEXT WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JB
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
648 AM EDT SAT SEP 15 2012
.SYNOPSIS...
ISSUED AT 341 AM EDT SAT SEP 15 2012
OUTSTANDING WEATHER IS EXPECTED THIS WEEKEND AS HIGH PRESSURE SLIDES
ACROSS THE GREAT LAKES. THE NEXT COLD FRONT WILL MOVE THROUGH ON
MONDAY...BRINGING THE NEXT CHANCE OF RAIN. LAKE EFFECT RAIN SHOWERS
MAY DEVELOP TUESDAY...AS MUCH COOLER AIR INVADES THE REGION.
&&
.UPDATE...
ISSUED AT 640 AM EDT SAT SEP 15 2012
BROKEN LAKE CLOUDS CONTINUE TO ROLL IN OFF LAKES MICHIGAN AND
HURON WITHIN A DRYING NORTHERLY FLOW. THESE CLOUDS ARE RATHER
THIN...AND DO NOT EXPECTED THEM TO LAST TOO MUCH AFTER SUNRISE
DUE TO MIXING INTO DRIER AIR. STILL LOOKING FOR A GOOD DEAL OF
SUNSHINE TODAY WITH LIGHT WINDS/AFTERNOON LAKE BREEZES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 341 AM EDT SAT SEP 15 2012
SHARP UPPER TROUGH WORKING INTO NEW ENGLAND WITH A SOLID NW FLOW
ALOFT OVER NRN MICHIGAN. ATMOSPHERIC SUBSIDENCE WITH DRY AIR
ADVECTION WITHIN ADVANCING SFC HIGH PRESSURE. STILL...VERY GOOD
OVERLAKE INSTABILITY HAS LED TO THE DEVELOPMENT OF STRATO CU IN
BACKING NW-W 1000-850MB FLOW...ATTACHED TO GREEN BAY. WINDS ARE
WEAKENING WITH TIME...SO FETCH AND INLAND PENETRATION WILL
CONTINUE LEAD TO LESS CLOUD...BUT THIS MAY TAKE THROUGH EARLY
DAYBREAK...WHEN MIXING INTO DRIER AIR ALOFT CAN HELP MIX IT ALL
OUT. TEMPERATURES WERE QUITE CHILLY...DIPPING INTO THE 30S IN
SEVERAL LOCALES OF NRN LOWER. SKIES WERE FAIRLY CLEAR ACROSS
EASTERN UPPER...WITH LATEST RUC ANALYSIS SUGGESTING A WEAKER WIND
FLOW AND LESS MOISTURE FLUX OFF WHITEFISH BAY/EASTERN LAKE
SUPERIOR. CANNOT RULE OUT SOME STRATO CU INTO CHIPPEWA COUNTY
THOUGH OVER THE NEXT FEW HOURS.
TODAY AND TONIGHT...VERY QUIET. SFC HIGH PRESSURE WILL MOVE IN
OVERHEAD WITH SOME SCATTERED CUMULUS DEVELOPMENT...MAINLY ALONG
THE AXIS OF THE SFC HIGH...AND AREAS EAST. THIS BRINGS THE BETTER
CU ACROSS NE LOWER AND EASTERN CHIP/MACK. BY LATER THIS
AFTERNOON...SOME LAKE BREEZES WILL TRY TO CONSOLIDATE THIS CLOUD
MORE INLAND. THE CLOUDS WILL QUICKLY ERODE TO CLEAR SKIES IN THE
EVENING WITH ONLY SOME SCATTERED MID CLOUD POSSIBLE OVERNIGHT.
THIS WILL BE AHEAD OF A WEAK SHORTWAVE AND LOW LEVEL WARM FRONT
LIFTING OUR WAY. A 30-35KT WSW ORIENTED LLJ COULD THEORETICALLY
RESULT IN SOME THIN CLOUDINESS LATE. WOULD HEDGE MY BETS ON A
FAIRLY CLEAR EVENING THOUGH. LOW TEMPS LIKELY IN THE LOW TO MID
40S WEST/NW CWA IN BETTER SW FLOW DEVELOPING...WITH THE COLDEST
MID TO UPPER 30S IN LOW LYING AREAS OF THE EASTERN CWA OF NRN
LOWER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 341 AM EDT SAT SEP 15 2012
HIGH PRESSURE AT THE SURFACE AND ALOFT SUNDAY IS EXPECTED TO LEAD TO
VERY PLEASANT WEATHER FOR THE LAST SUNDAY OF SUMMER (THE AUTUMNAL
EQUINOX IS EARLY SATURDAY MORNING ON SEPTEMBER 22ND). A COLD FRONT
WILL THEN MOVE ACROSS THE REGION LATER MONDAY SETTING THE STAGE FOR
LONG WAVE TROUGHING TO SETTLE INTO THE REGION FOR MUCH OF NEXT WEEK.
THIS WILL LEAD TO AN EXTENDED PERIOD OF COOLER AND UNSETTLED
WEATHER. THE MAIN LONG TERM FORECAST CONCERNS REVOLVE AROUND POPS
FOR ALL OF NEXT WEEK.
SUNDAY...SURFACE HIGH PRESSURE SHIFTS OFF TO OUR EAST WHILE UPPER
LEVEL HEIGHTS MAX/FLATTEN OUT. THIS IS EXPECTED TO LEAD TO LOTS OF
SUNSHINE AND MILD TEMPERATURES WITH HIGHS RANGING FROM THE MIDDLE
70S TO LOWER 80S.
SUNDAY NIGHT INTO MONDAY NIGHT...PARTLY CLOUDY SKIES WITH MILDER
TEMPERATURES SUNDAY NIGHT AS SOUTHWEST WINDS STAY UP A BIT. A COLD
FRONT MOVES ACROSS THE REGION LATER MONDAY LIKELY BRINGING SHOWERS.
LOWS SUNDAY NIGHT IN THE 50S WITH HIGHS ON MONDAY RANGING FROM THE
MIDDLE AND UPPER 60S NORTH TO THE MIDDLE AND UPPER 70S SOUTHEAST.
LOWS MONDAY NIGHT IN THE MIDDLE 40S TO LOWER 50S.
TUESDAY...HEIGHTS CONTINUE TO FALL AND COMBINE WITH INCREASING OVER
LAKE INSTABILITY (AS 850 MB TEMPERATURES FALL TO BETWEEN ZERO AND -2
C) AND A SHORT WAVE MOVING THROUGH THE FLOW TO PRODUCE A CHANCE OF
RAIN SHOWERS. THE MEAN FLOW APPEARS TO BE NORTH OR NORTH NORTHWEST
SO LOCALS NEAR THE LAKE SHORES WILL LIKELY HAVE THE BEST SHOT OF
RAIN. HIGHS RANGING FROM THE MUCH COOLER LOWER 50S NORTH TO AROUND
60 SOUTHEAST.
TUESDAY NIGHT...A WEDGE OF DRIER AIR IN COMBINATION WITH HIGH
PRESSURE NOSING IN FROM THE NORTH WILL SET THE STAGE FOR A VERY
CHILLY NIGHT. IF WINDS DECOUPLE...AND RIGHT NOW IT LOOKS LIKE THEY
WILL...THIS COULD LEAD TO THE FIRST SIGNIFICANT FROST OR FREEZE OF
THE SEASON.
WEDNESDAY THROUGH FRIDAY...ENERGY RIDING SOUTHEAST ON THE BACKSIDE
OF A BLOSSOMING PACIFIC RIDGE AMPLIFIES THE LONG WAVE TROUGH ACROSS
THE GREAT LAKES. SO THIS IN COMBINATION WITH PERIODIC SHORT WAVES
MOVING THROUGH THE FLOW AND INCREASING OVER LAKE INSTABILITY BRINGS
MORE CHANCES FOR RAIN SHOWERS. THE DETAILS OF WHICH WILL NEED TO BE
WORKED OUT BY FUTURE SHIFTS. HIGHS GENERALLY RANGING FROM THE MIDDLE
50S TO THE MIDDLE 60S. LOWS IN THE UPPER 30S AND 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 640 AM EDT SAT SEP 15 2012
LOW LEVEL BKN MVFR LAKE CLOUDS WILL CONTINUE TO AFFECT THE
TVC/PLN/APN AREAS THROUGH AN HOUR OR TWO AFTER SUNRISE...AND WILL
BE HANDLED BY A TEMPO GROUP. HIGH PRESSURE STILL SETTLES IN FOR
TODAY AND TONIGHT...AND MIXING INTO DRIER AIR WILL RESULT IN JUST
SOME SCATTERED CU THIS AFTERNOON. THESE CLOUDS WILL LIKELY DEPART
THE AIRPORTS BY LATE AFTERNOON DUE TO LAKE BREEZE DEVELOPMENT. CALM
WINDS TONIGHT WITH ONLY THE CHANCE FOR SCATTERED LOW TO MID
CLOUDS. MAINLY CLEAR THOUGH.
&&
.MARINE...
ISSUED AT 159 AM EDT SAT SEP 15 2012
DROPPED SMALL CRAFT ADVISORY ACROSS THE NE LOWER NEARSHORE WATERS
UNDER A WEAKENING LOW LEVEL WIND FIELD...WITH SUPPORT FROM LATEST
MARINE OBS. THIS DESPITE GOOD OVERLAKE INSTABILITY...BUT GUSTY
WINDS ARE LIKELY...ESPECIALLY OVER LAKE HURON. HIGH PRESSURE WILL
THEN SETTLE INTO THE REGION TODAY FOR ONSHORE LAKE BREEZES IN THE
AFTERNOON. THIS HIGH EXITS EAST TONIGHT WITH SOUTHERLY WINDS
RETURNING. THERE IS AN OUTSIDE CHANCE AT SOME LOW END ADVISORY
LEVEL WINDS IN COASTAL CONVERGENCE REGIONS FROM MANISTEE THROUGH
THE MANITOU ISLANDS. CONFIDENCE IS LOW AT THIS POINT...ESPECIALLY
WITH LOW LEVEL WARMING AND INCREASING STABILITY. THESE SAME
ADVISORY POSSIBILITIES CONTINUE THROUGH SUNDAY NIGHT IN ADVANCE OF
THE NEXT LOW PRESSURE AND COLD FRONT WHICH PASSES MONDAY.
INSTABILITY OVER THE LAKES INCREASES RELATIVELY SUBSTANTIALLY
BEHIND THIS FRONT FOR WHAT COULD VERY WELL TURN OUT TO BE THE
BETTER CHANCES FOR ADVISORIES. UNSTABLE CONDITIONS ARE EXPECTED TO
HOLD FROM MONDAY NIGHT ALL THE WAY THROUGH NEXT WORK WEEK AND
POSSIBLY NEXT WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
408 AM EDT SAT SEP 15 2012
.SYNOPSIS...
ISSUED AT 341 AM EDT SAT SEP 15 2012
OUTSTANDING WEATHER IS EXPECTED THIS WEEKEND AS HIGH PRESSURE SLIDES
ACROSS THE GREAT LAKES. THE NEXT COLD FRONT WILL MOVE THROUGH ON
MONDAY...BRINGING THE NEXT CHANCE OF RAIN. LAKE EFFECT RAIN SHOWERS
MAY DEVELOP TUESDAY...AS MUCH COOLER AIR INVADES THE REGION.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 341 AM EDT SAT SEP 15 2012
SHARP UPPER TROUGH WORKING INTO NEW ENGLAND WITH A SOLID NW FLOW
ALOFT OVER NRN MICHIGAN. ATMOSPHERIC SUBSIDENCE WITH DRY AIR
ADVECTION WITHIN ADVANCING SFC HIGH PRESSURE. STILL...VERY GOOD
OVERLAKE INSTABILITY HAS LED TO THE DEVELOPMENT OF STRATO CU IN
BACKING NW-W 1000-850MB FLOW...ATTACHED TO GREEN BAY. WINDS ARE
WEAKENING WITH TIME...SO FETCH AND INLAND PENETRATION WILL
CONTINUE LEAD TO LESS CLOUD...BUT THIS MAY TAKE THROUGH EARLY
DAYBREAK...WHEN MIXING INTO DRIER AIR ALOFT CAN HELP MIX IT ALL
OUT. TEMPERATURES WERE QUITE CHILLY...DIPPING INTO THE 30S IN
SEVERAL LOCALES OF NRN LOWER. SKIES WERE FAIRLY CLEAR ACROSS
EASTERN UPPER...WITH LATEST RUC ANALYSIS SUGGESTING A WEAKER WIND
FLOW AND LESS MOISTURE FLUX OFF WHITEFISH BAY/EASTERN LAKE
SUPERIOR. CANNOT RULE OUT SOME STRATO CU INTO CHIPPEWA COUNTY
THOUGH OVER THE NEXT FEW HOURS.
TODAY AND TONIGHT...VERY QUIET. SFC HIGH PRESSURE WILL MOVE IN
OVERHEAD WITH SOME SCATTERED CUMULUS DEVELOPMENT...MAINLY ALONG
THE AXIS OF THE SFC HIGH...AND AREAS EAST. THIS BRINGS THE BETTER
CU ACROSS NE LOWER AND EASTERN CHIP/MACK. BY LATER THIS
AFTERNOON...SOME LAKE BREEZES WILL TRY TO CONSOLIDATE THIS CLOUD
MORE INLAND. THE CLOUDS WILL QUICKLY ERODE TO CLEAR SKIES IN THE
EVENING WITH ONLY SOME SCATTERED MID CLOUD POSSIBLE OVERNIGHT.
THIS WILL BE AHEAD OF A WEAK SHORTWAVE AND LOW LEVEL WARM FRONT
LIFTING OUR WAY. A 30-35KT WSW ORIENTED LLJ COULD THEORETICALLY
RESULT IN SOME THIN CLOUDINESS LATE. WOULD HEDGE MY BETS ON A
FAIRLY CLEAR EVENING THOUGH. LOW TEMPS LIKELY IN THE LOW TO MID
40S WEST/NW CWA IN BETTER SW FLOW DEVELOPING...WITH THE COLDEST
MID TO UPPER 30S IN LOW LYING AREAS OF THE EASTERN CWA OF NRN
LOWER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 341 AM EDT SAT SEP 15 2012
HIGH PRESSURE AT THE SURFACE AND ALOFT SUNDAY IS EXPECTED TO LEAD TO
VERY PLEASANT WEATHER FOR THE LAST SUNDAY OF SUMMER (THE AUTUMNAL
EQUINOX IS EARLY SATURDAY MORNING ON SEPTEMBER 22ND). A COLD FRONT
WILL THEN MOVE ACROSS THE REGION LATER MONDAY SETTING THE STAGE FOR
LONG WAVE TROUGHING TO SETTLE INTO THE REGION FOR MUCH OF NEXT WEEK.
THIS WILL LEAD TO AN EXTENDED PERIOD OF COOLER AND UNSETTLED
WEATHER. THE MAIN LONG TERM FORECAST CONCERNS REVOLVE AROUND POPS
FOR ALL OF NEXT WEEK.
SUNDAY...SURFACE HIGH PRESSURE SHIFTS OFF TO OUR EAST WHILE UPPER
LEVEL HEIGHTS MAX/FLATTEN OUT. THIS IS EXPECTED TO LEAD TO LOTS OF
SUNSHINE AND MILD TEMPERATURES WITH HIGHS RANGING FROM THE MIDDLE
70S TO LOWER 80S.
SUNDAY NIGHT INTO MONDAY NIGHT...PARTLY CLOUDY SKIES WITH MILDER
TEMPERATURES SUNDAY NIGHT AS SOUTHWEST WINDS STAY UP A BIT. A COLD
FRONT MOVES ACROSS THE REGION LATER MONDAY LIKELY BRINGING SHOWERS.
LOWS SUNDAY NIGHT IN THE 50S WITH HIGHS ON MONDAY RANGING FROM THE
MIDDLE AND UPPER 60S NORTH TO THE MIDDLE AND UPPER 70S SOUTHEAST.
LOWS MONDAY NIGHT IN THE MIDDLE 40S TO LOWER 50S.
TUESDAY...HEIGHTS CONTINUE TO FALL AND COMBINE WITH INCREASING OVER
LAKE INSTABILITY (AS 850 MB TEMPERATURES FALL TO BETWEEN ZERO AND -2
C) AND A SHORT WAVE MOVING THROUGH THE FLOW TO PRODUCE A CHANCE OF
RAIN SHOWERS. THE MEAN FLOW APPEARS TO BE NORTH OR NORTH NORTHWEST
SO LOCALS NEAR THE LAKE SHORES WILL LIKELY HAVE THE BEST SHOT OF
RAIN. HIGHS RANGING FROM THE MUCH COOLER LOWER 50S NORTH TO AROUND
60 SOUTHEAST.
TUESDAY NIGHT...A WEDGE OF DRIER AIR IN COMBINATION WITH HIGH
PRESSURE NOSING IN FROM THE NORTH WILL SET THE STAGE FOR A VERY
CHILLY NIGHT. IF WINDS DECOUPLE...AND RIGHT NOW IT LOOKS LIKE THEY
WILL...THIS COULD LEAD TO THE FIRST SIGNIFICANT FROST OR FREEZE OF
THE SEASON.
WEDNESDAY THROUGH FRIDAY...ENERGY RIDING SOUTHEAST ON THE BACKSIDE
OF A BLOSSOMING PACIFIC RIDGE AMPLIFIES THE LONG WAVE TROUGH ACROSS
THE GREAT LAKES. SO THIS IN COMBINATION WITH PERIODIC SHORT WAVES
MOVING THROUGH THE FLOW AND INCREASING OVER LAKE INSTABILITY BRINGS
MORE CHANCES FOR RAIN SHOWERS. THE DETAILS OF WHICH WILL NEED TO BE
WORKED OUT BY FUTURE SHIFTS. HIGHS GENERALLY RANGING FROM THE MIDDLE
50S TO THE MIDDLE 60S. LOWS IN THE UPPER 30S AND 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 159 AM EDT SAT SEP 15 2012
NO AVIATION CONCERNS OUTSIDE THE NEXT FEW HOURS OR SO. COLD LOW
LEVEL AIR IS RESULTING IN OVERLAKE INSTABILITY AND THE DEVELOPMENT
OF MARGINAL MVFR BKN CIGS AT TVC. THIS SHOULD BE FEW AND FAR
BETWEEN AS THE AIR MASS IS ALSO DRYING WITH WEAKENING NORTHERLY
LOW LEVEL FLOW. HIGH PRESSURE AND DRY AIR CONTINUE TO SETTLE IN
OVER THE REGION TODAY AND TOMORROW FOR A QUICK PERIOD OF SCATTERED
CU...BECOMING SKC IN MBL/TVC AND LIKELY PLN/APN BY LATER IN THE
AFTERNOON WITH LAKES BREEZES. SKIES WILL BE CLEAR HEADING THROUGH
THE NIGHT...WITH ONLY SOME SCT MID CLOUD LOOKING POSSIBLE.
&&
.MARINE...
ISSUED AT 159 AM EDT SAT SEP 15 2012
DROPPED SMALL CRAFT ADVISORY ACROSS THE NE LOWER NEARSHORE WATERS
UNDER A WEAKENING LOW LEVEL WIND FIELD...WITH SUPPORT FROM LATEST
MARINE OBS. THIS DESPITE GOOD OVERLAKE INSTABILITY...BUT GUSTY
WINDS ARE LIKELY...ESPECIALLY OVER LAKE HURON. HIGH PRESSURE WILL
THEN SETTLE INTO THE REGION TODAY FOR ONSHORE LAKE BREEZES IN THE
AFTERNOON. THIS HIGH EXITS EAST TONIGHT WITH SOUTHERLY WINDS
RETURNING. THERE IS AN OUTSIDE CHANCE AT SOME LOW END ADVISORY
LEVEL WINDS IN COASTAL CONVERGENCE REGIONS FROM MANISTEE THROUGH
THE MANITOU ISLANDS. CONFIDENCE IS LOW AT THIS POINT...ESPECIALLY
WITH LOW LEVEL WARMING AND INCREASING STABILITY. THESE SAME
ADVISORY POSSIBILITIES CONTINUE THROUGH SUNDAY NIGHT IN ADVANCE OF
THE NEXT LOW PRESSURE AND COLD FRONT WHICH PASSES MONDAY.
INSTABILITY OVER THE LAKES INCREASES RELATIVELY SUBSTANTIALLY
BEHIND THIS FRONT FOR WHAT COULD VERY WELL TURN OUT TO BE THE
BETTER CHANCES FOR ADVISORIES. UNSTABLE CONDITIONS ARE EXPECTED TO
HOLD FROM MONDAY NIGHT ALL THE WAY THROUGH NEXT WORK WEEK AND
POSSIBLY NEXT WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1200 PM MDT SAT SEP 15 2012
.DISCUSSION...
UPDATE FORTHCOMING. HAVE ADJUSTED POPS AND WEATHER GRIDS ALONG THE
HI-LINE THIS MORNING. BOTH THE GFS AND EUROPEAN MODELS DEVELOP A
LITTLE QPF ACROSS THE HI-LINE AS WEAK SHORTWAVE ENERGY PROPAGATES
EASTWARD WITHIN THE FLOW ALOFT. HRRR ANALYSIS ALSO HINTS AT A FEW
WEAK RETURNS DURING THE MORNING HOURS. LITTLE...IF
ANY...ACCUMULATION EXPECTED. REMAINDER OF FORECAST LOOKS ON TRACK.
EMANUEL
&&
.AVIATION...
UPDATED 1800Z.
EXPECT VFR CONDITIONS WITH THE EXCEPTION OF LOCAL MVFR VISIBILITIES
IN SMOKE OVER SOUTHWEST MONTANA. A WEAK COLD FRONT MOVING SOUTH THIS
MORNING SHIFTED WINDS TO THE NORTH. CEILINGS SHOULD GENERALLY BE AT
OR ABOVE 12000 FT INTO TONIGHT. A FEW SHOWERS WILL DEVELOP IN THE
NORTH AFTER MIDNIGHT AND COULD SEE CEILINGS LOWER TO NEAR 5000 FT
NEAR ANY SHOWERS. TERMINALS AT KHVR AND KLWT MAY SEE SOME MORNING
SHOWERS SUNDAY BEFORE SKIES CLEAR IN THE AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 326 AM MDT SAT SEP 15 2012
SATURDAY THROUGH MONDAY...
WINDS WILL AGAIN DEVELOP TODAY AS A COLD FRONT APPROACHES AND
EVENTUALLY MOVES ACROSS THE AREA. MODELS STILL VARY ON TIMING OF
THE FRONT ACROSS THE AREA...HOWEVER IT SHOULD MOVE ACROSS MOST OF
CENTRAL AND NORTH CENTRAL MONTANA TO LIMIT MAXIMUM TEMPERATURES
TODAY INTO THE UPPER 70S AND LOW 80S. WINDS WILL BE BREEZY AT
TIMES...HOWEVER THE STRONGEST WINDS ARE NOT EXPECTED TO
COINCIDE WITH THE LOWEST RH VALUES AND FIRE WEATHER HIGHLITES ARE
NOT EXPECTED AT THIS TIME. WIDESPREAD PRECIPITATION IS NOT
EXPECTED WITH THIS FRONTAL PASSAGE OR THE NORTHWEST FLOW BEHIND IT
WITH THE BEST CHANCE OF SHOWERS SUNDAY. ANY SHOWERS THAT DO DEVELOP
THIS WEEKEND WILL BE LIGHT ISOLATED AND SHORT LIVED. TEMPERATURES
WILL COOL DOWN SUNDAY WITH MAXIMUM TEMPERATURES STRUGGLING TO REACH
INTO THE 70S. LOWS MONDAY MORNING WILL BE APPROACHING FREEZING AT
MANY LOCATIONS ACROSS THE AREA...HOWEVER BY MONDAY HIGH TEMPERATURES
WILL BE CLIMBING INTO THE 70S AGAIN AS THE COLD AIR MASS STARTS TO
TRANSITION EASTWARD. SUK
MONDAY NIGHT THROUGH SATURDAY...MODELS ARE IN AGREEMENT IN
FORECASTING A NORTHWEST FLOW ALOFT THROUGH THE PERIOD AS A STRONG
RIDGE ALOFT BECOMES ESTABLISHED FROM THE WEST COAST STATES TO
WESTERN CANADA. ALTHOUGH THERE WILL OCCASIONALLY BE WEAK WEATHER
DISTURBANCES EMBEDDED IN THIS FLOW..NOT ONLY DO NOT SEE ANY THREAT
FOR PRECIPITATION DO NOT EXPECT MUCH IN THE WAY OF CLOUDINESS. HIGH
TEMPERATURES SHOULD BE RELATIVELY STABLE RANGING FROM THE MID 70S TO
LOWER 80S THROUGH THE PERIOD. GUSTY WEST TO NORTHWEST WINDS MIGHT
AFFECT THE PLAINS ON TUESDAY AS A COLD FRONT MOVES THROUGH THE AREA.
BLANK
&&
.FIRE WEATHER...RELATIVE HUMIDITIES WILL ONCE AGAIN DROP INTO THE
TEENS AND SINGLE DIGITS SATURDAY BUT THE WINDS WILL NOT BE AS
STRONG...BREEZY WINDS WILL BE POSSIBLE ALONG THE HILINE.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE FORECAST AREA TUESDAY.
GUSTY WEST WINDS COULD DEVELOP AHEAD OF THE COLD FRONT THEN BECOME
GUSTY OUT OF THE NORTHWEST BEHIND THE FRONT. THESE WINDS COMBINED
WITH EXPECTED LOW RELATIVE HUMIDITIES COULD CREATE CRITICAL FIRE
WEATHER CONDITIONS. NO SHOWERS OR THUNDERSTORMS ARE EXPECTED WITH
THIS FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 80 47 66 39 / 0 10 0 0
CTB 73 42 64 33 / 0 20 10 0
HLN 82 49 71 39 / 0 0 10 0
BZN 83 41 72 32 / 0 10 20 10
WEY 74 30 67 23 / 10 10 20 10
DLN 82 41 71 35 / 10 10 10 10
HVR 82 46 67 35 / 0 20 20 0
LWT 81 44 62 35 / 0 10 10 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
925 AM MDT SAT SEP 15 2012
.DISCUSSION...
UPDATE FORTHCOMING. HAVE ADJUSTED POPS AND WEATHER GRIDS ALONG THE
HI-LINE THIS MORNING. BOTH THE GFS AND EUROPEAN MODELS DEVELOP A
LITTLE QPF ACROSS THE HI-LINE AS WEAK SHORTWAVE ENERGY PROPAGATES
EASTWARD WITHIN THE FLOW ALOFT. HRRR ANALYSIS ALSO HINTS AT A FEW
WEAK RETURNS DURING THE MORNING HOURS. LITTLE...IF
ANY...ACCUMULATION EXPECTED. REMAINDER OF FORECAST LOOKS ON TRACK.
EMANUEL
&&
.AVIATION...
UPDATED 1110Z.
EXPECT VFR CONDITIONS WITH THE EXCEPTION OF LOCAL MVFR VISIBILITIES
IN SMOKE OVER SOUTHWEST MONTANA. A COLD FRONT WILL SWEEP SOUTH THIS
MORNING SHIFTING WINDS TO THE NORTHWEST TO NORTH. HAVE ONLY FAIR
CONFIDENCE IN THE TIMING OF THE WIND SWITCH ALONG WITH FORECAST
DIRECTIONS. CEILINGS SHOULD GENERALLY BE ABOVE 12000 FT INTO
TONIGHT. AHEAD OF A CANADIAN WEATHER SYSTEM A FEW SHOWERS WILL
DEVELOP IN THE NORTH AFTER MIDNIGHT AND COULD SEE CEILINGS LOWER TO
NEAR 5000 FT WITH THE SHOWERS. BLANK
&&
.PREV DISCUSSION...ISSUED 326 AM MDT SAT SEP 15 2012
SATURDAY THROUGH MONDAY...
WINDS WILL AGAIN DEVELOP TODAY AS A COLD FRONT APPROACHES AND
EVENTUALLY MOVES ACROSS THE AREA. MODELS STILL VARY ON TIMING OF
THE FRONT ACROSS THE AREA...HOWEVER IT SHOULD MOVE ACROSS MOST OF
CENTRAL AND NORTH CENTRAL MONTANA TO LIMIT MAXIMUM TEMPERATURES
TODAY INTO THE UPPER 70S AND LOW 80S. WINDS WILL BE BREEZY AT
TIMES...HOWEVER THE STRONGEST WINDS ARE NOT EXPECTED TO
COINCIDE WITH THE LOWEST RH VALUES AND FIRE WEATHER HIGHLITES ARE
NOT EXPECTED AT THIS TIME. WIDESPREAD PRECIPITATION IS NOT
EXPECTED WITH THIS FRONTAL PASSAGE OR THE NORTHWEST FLOW BEHIND IT
WITH THE BEST CHANCE OF SHOWERS SUNDAY. ANY SHOWERS THAT DO DEVELOP
THIS WEEKEND WILL BE LIGHT ISOLATED AND SHORT LIVED. TEMPERATURES
WILL COOL DOWN SUNDAY WITH MAXIMUM TEMPERATURES STRUGGLING TO REACH
INTO THE 70S. LOWS MONDAY MORNING WILL BE APPROACHING FREEZING AT
MANY LOCATIONS ACROSS THE AREA...HOWEVER BY MONDAY HIGH TEMPERATURES
WILL BE CLIMBING INTO THE 70S AGAIN AS THE COLD AIR MASS STARTS TO
TRANSITION EASTWARD. SUK
MONDAY NIGHT THROUGH SATURDAY...MODELS ARE IN AGREEMENT IN
FORECASTING A NORTHWEST FLOW ALOFT THROUGH THE PERIOD AS A STRONG
RIDGE ALOFT BECOMES ESTABLISHED FROM THE WEST COAST STATES TO
WESTERN CANADA. ALTHOUGH THERE WILL OCCASIONALLY BE WEAK WEATHER
DISTURBANCES EMBEDDED IN THIS FLOW..NOT ONLY DO NOT SEE ANY THREAT
FOR PRECIPITATION DO NOT EXPECT MUCH IN THE WAY OF CLOUDINESS. HIGH
TEMPERATURES SHOULD BE RELATIVELY STABLE RANGING FROM THE MID 70S TO
LOWER 80S THROUGH THE PERIOD. GUSTY WEST TO NORTHWEST WINDS MIGHT
AFFECT THE PLAINS ON TUESDAY AS A COLD FRONT MOVES THROUGH THE AREA.
BLANK
&&
.FIRE WEATHER...RELATIVE HUMIDITIES WILL ONCE AGAIN DROP INTO THE
TEENS AND SINGLE DIGITS SATURDAY BUT THE WINDS WILL NOT BE AS
STRONG...BREEZY WINDS WILL BE POSSIBLE ALONG THE HILINE.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE FORECAST AREA TUESDAY.
GUSTY WEST WINDS COULD DEVELOP AHEAD OF THE COLD FRONT THEN BECOME
GUSTY OUT OF THE NORTHWEST BEHIND THE FRONT. THESE WINDS COMBINED
WITH EXPECTED LOW RELATIVE HUMIDITIES COULD CREATE CRITICAL FIRE
WEATHER CONDITIONS. NO SHOWERS OR THUNDERSTORMS ARE EXPECTED WITH
THIS FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 80 47 66 39 / 0 10 0 0
CTB 73 42 64 33 / 0 20 10 0
HLN 82 49 71 39 / 0 0 10 0
BZN 83 41 72 32 / 0 10 20 10
WEY 74 30 67 23 / 10 10 20 10
DLN 82 41 71 35 / 10 10 10 10
HVR 82 46 67 35 / 0 20 20 0
LWT 81 44 62 35 / 0 10 10 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...EMANUEL/SUK
LONG TERM...BLANK
AVIATION...BLANK
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
615 PM CDT SUN SEP 16 2012
.AVIATION...00Z TAF. THE MAIN FORECAST ISSUE FOR THIS PERIOD IS A
STRONG COLD FRONT PASSING THROUGH KGRI AROUND 08Z. WINDS PRIOR TO
THE FRONT WILL BE SOUTHERLY...AND WITH INCREASING MOISTURE AND
LOWERING WINDS SPEEDS...HAVE ADDED A LITTLE BIT OF HAZE JUST PRIOR
TO FRONTAL PASSAGE AS SUGGESTED BY HRRR MODEL. THE FRONT IS LIKELY
TO BE DRY WITH ONLY MID/HIGH CLOUDS EXPECTED. WINDS WILL GUST TO
NEAR 30 KTS AT TIMES DURING THE DAY MONDAY FROM THE NORTH.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY. CONCERN WILL BE TEMPERATURES
AND SMALL...IF ANY...CHANCES FOR PRECIPITATION.
VISIBLE SATELLITE IMAGERY SHOWING STUBBORN FOG/STRATUS AREA THAT
DEVELOPED/MOVED IN TO THE CWA OVERNIGHT HAS TAKEN THE ENTIRE MORNING
TO DISSIPATE ESPECIALLY IN THE SOUTH AND SOUTHEAST PART OF THE CWA.
THIS HAS HELD TEMPERATURES DOWN AND KEPT DEWPOINTS UP WHICH HAS
ALLEVIATED ANY FIRE WEATHER CONCERNS FOR THIS AFTERNOON. IN THE
UPPER LEVELS OF THE ATMOSPHERE...WATER VAPOR IMAGERY DENOTES A RIDGE
BUILDING INTO THE PACIFIC NW AND WESTERN CANADA WITH THIS
AMPLIFICATION ALLOWING A TROUGH OVER SOUTHERN ALBERTA AND
SASKATCHEWAN TO DIG SSE. THIS FEATURE WILL HELP DRAG A COLD FRONT
THROUGH OUR AREA TONIGHT. BY EARLY AFTERNOON THIS FRONT STRETCHED
FROM SOUTHERN MN TO ALONG THE NEB/SDAK BORDER AND THEN INTO THE SW
NEB PANHANDLE. NOT SEEING ANY STRONG PRESSURE FALLS AHEAD OF THE
FRONT BUT HEIGHT RISES OF 1-2 MB PER 3 HOURS NOTED ACROSS MONTANA
AND NDAK.
STILL LOOKING LIKE FRONT WILL ENTER THE NORTHWEST CWA A FEW HOURS
AFTER SUNSET AND SHOULD PROGRESS QUICKLY...EXITING THE SOUTHERN CWA
A LITTLE BEFORE SUNRISE MONDAY. NORTH WINDS SHOULD BE QUITE GUSTY
BEHIND THE FRONT...OVER 25 MPH BEFORE LETTING UP SOME MONDAY
AFTERNOON AS THE PRESSURE GRADIENT WEAKENS WITH HIGH PRESSURE
BUILDING DOWN FROM THE NORTH. PLENTY OF MORNING CLOUDS AND COLD AIR
ADVECTION WILL HOLD HIGHS ON MONDAY IN THE MID 60S NORTH TO UPPER
60S SOUTH. RAIN CHANCES STILL A TOUGH CALL AS MODEL SOUNDINGS
SHOWING PLENTY OF LOW LEVEL DRY AIR TO OVERCOME WHILE BETTER FORCING
REMAINS TO THE NORTHEAST. SOME MODELS...INCLUDING THE 4KM
WRF...SHOWING JUST SOME LIGHT SHOWERS AT BEST. PROGGED CAPE VALUES
FROM VARIOUS MODELS ALSO NOT VERY ROBUST AND WILL NEED TO DECIDE IF
THUNDER SHOULD BE INCLUDED...PROVIDING I KEEP THE CHANCE FOR RAIN IN
THE GRIDS.
.LONG TERM...TUESDAY THROUGH SUNDAY. THIS SHOULD BE AN EXTENDED DRY
PERIOD WITH TEMPERATURES ON MOST DAYS GENERALLY RANGING FROM NEAR
NORMAL TO BELOW NORMAL. THE ONLY DAY CURRENTLY PROJECTED TO BE
ABOVE NORMAL IS WEDNESDAY WHEN HIGHS WILL CLIMB INTO THE LOWER TO
MIDDLE 80S. NORMAL HIGHS FOR THIS WEEK ARE IN THE UPPER 70S.
TUESDAY...TEMPERATURES WILL START TO MODERATE ON TUESDAY...BUT NOT
BEFORE A RATHER CHILLY START. ZONES NORTH OF HWY 92 MAY FALL INTO
THE MID TO UPPER 30S EARLY TUESDAY MORNING...BUT WILL NOT MENTION
FROST AT THIS POINT IN TIME AS THERE COULD BE SOME HIGH CLOUDS
AROUND AND THE SFC HIGH IS NORTHEAST OF OUR CWA SO THERE SHOULD
STILL BE SOME LIGHT WINDS. COULD SEE A NICE 10 DEGREE BOUNCE IN
HIGH TEMPERATURES ON TUESDAY FROM THE COOL START TO THE WEEK ON
MONDAY.
WEDNESDAY...THE PRIMARY FORECAST CONCERN WILL BE NEAR CRITICAL FIRE
WEATHER CONDITIONS AS HIGHS WARM INTO THE 80S ALLOWING FOR LOW RH
VALUES GIVEN THE DRY AIR MASS OVERHEAD. HOWEVER...THE WIND MAY BE
JUST A BIT TOO WEAK FOR CRITICAL FIRE WEATHER
CONDITIONS...ALTHOUGH IT COULD STILL BE FAIRLY CLOSE. THERE WILL
BE COLD FRONT SWINGING SOUTHEAST THROUGH THE CWA WEDNESDAY
AFTERNOON AND EVENING...WHICH WILL MAKE THE TEMPERATURE FORECAST
AND FIRE WEATHER FORECAST A BIT MORE CHALLENGING WHILE LOWERING
OVERALL FORECAST CONFIDENCE DURING THIS PERIOD.
THURSDAY THROUGH SUNDAY WILL BE A COOL/MILD PERIOD WITH HIGHS
GENERALLY IN THE 70S. A LARGE UPPER TROUGH WILL DIG JUST TO OUR
EAST ALLOWING FOR CONTINUED NORTHERLY TO NORTHWESTERLY FLOW
THROUGH A GOOD PORTION OF THIS PERIOD. DRY WEATHER SHOULD CONTINUE.
&&
.AVIATION...18Z KGRI TAF. EXPECT VFR CONDITIONS THROUGH THE
FORECAST PERIOD. WINDS WILL BE GUSTY OUT OF THE SOUTH THIS
AFTERNOON AHEAD OF A COLD FRONT THAT SHOULD PASS THROUGH TERMINAL
AREA BETWEEN 07Z AND 09Z. STRONG WINDS OUT OF THE NORTH WILL THEN
PREVAIL THROUGH THE END OF THE FORECAST PERIOD WITH TIGHT PRESSURE
GRADIENT BEHIND THE FRONT. VERY SMALL CHANCES FOR POST FRONTAL
RAIN BUT THESE ARE LESS THAN 30 PERCENT SO WILL LEAVE OUT OF THE
TAF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
NOAA/NWS/MORITZ
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
143 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE NORTH COUNTRY OVERNIGHT BRINGING
A CHANCE OF SHOWERS TO THE REGION. A RIDGE OF HIGH PRESSURE WILL
BUILD INTO THE REGION ON SATURDAY AND WILL REMAIN THROUGH MONDAY.
A LOW PRESSURE AREA MOVING INTO THE REGION ON TUESDAY WILL BRING
SOME HEAVY RAIN TO THE NORTH COUNTRY TUESDAY AND TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 120 AM EDT SATURDAY...MINOR UPDATE TO GOING FORECAST THIS
EARLY AM MAINLY TO ADJUST POPS FROM THE CHAMPLAIN VALLEY EASTWARD.
INITIAL PRE-FRONTAL TROUGH HAD PASSED THROUGH THE REGION WITH MAIN
COLD FRONT STILL OFF TO OUR WEST. WHAT WAS A RAGGED LINE OF
SHOWERS ACROSS NORTHERN NEW YORK HAS REDEVELOPED INTO A FAIR SHARP
LINE OF SHOWERS COMING INTO THE CHAMPLAIN VALLEY. 3KM HRRR MODEL
HAS THIS HANDLED VERY WELL...INCLUDING A BRIEF 1-2 HOUR PERIOD OF
EASTERLY WINDS AHEAD OF THE RAIN WHICH IS OCCURRING AT THE SURFACE
RIGHT NOW. HRRR HOLDS INTO HIGHER POPS EAST OF THE GREENS NOT SO
HAVE BUMPED UP A BIT FOR AT LEAST A 1 HOUR PERIOD OF LIKELY
SHOWERS. STILL NOT LOOKING AT A BUNCH OF PRECIP WITH THIS THING
THOUGH AS UPSTREAM OBS SHOWING MAINLY LESS THAN A TENTH OF AN INCH
HAS FALLEN.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS OF 433 PM EDT FRIDAY...SOME SHORTWAVES TO DROP THROUGH THE
REGION SATURDAY MORNING SO HAVE GONE WITH SLIGHT CHANCE POPS FOR
SHOWERS ACROSS THE NORTHERN ADIRONDACKS AND NORTHERN VERMONT. DEW
POINTS DROP DURING THE DAY AND BTV 4 KM MODEL NOT SHOWING ANY
SHOWER ACTIVITY DURING SATURDAY AFTERNOON. SKIES CLEARING OUT
SATURDAY NIGHT AND WILL REMAIN MOSTLY CLEAR THROUGH SUNDAY
NIGHT...AS A RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION. THERE
WILL BE A FEEL OF FALL IN THE AIR SATURDAY AND SUNDAY...AS MAX
TEMPERATURES WILL BE MAINLY IN THE 60S ON BOTH DAYS. MIN
TEMPERATURES SATURDAY NIGHT AND SUNDAY NIGHT WILL BE MAINLY IN THE
30S...WITH SOME UPPER 20S IN THE ADIRONDACKS...AND TEMPERATURES
AROUND 40 IN THE CHAMPLAIN VALLEY. EXPECTING AREAS OF FROST AROUND
THE REGION LATE SATURDAY NIGHT AND EARLY SUNDAY MORNING...AND ALSO
AGAIN LATE SUNDAY NIGHT AND EARLY MONDAY MORNING. ALSO EXPECTING
SOME RADIATION FOG TO FORM OVER THE SHELTERED FOG PRONE VALLEYS OF
EASTERN AND NORTHEAST VERMONT LATE SATURDAY NIGHT AND ALSO AGAIN
LATE SUNDAY NIGHT... AS CLEAR SKIES AND NEARLY CALM WINDS WILL
PROVIDE IDEAL CONDITIONS FOR RADIATION FOG TO FORM...MAINLY IN THE
RIVER VALLEYS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 339 PM EDT FRIDAY...LONGER RANGE GUIDANCE REMAINS IN PRETTY
DECENT AGREEMENT FOR ALL OF NEXT WEEK, SO OVERALL CONFIDENCE IN
THE FORECAST DETAILS ARE AT THE MODERATE LEVEL. DAILY DETAILS FOLLOW:
MONDAY: HIGH PRESSURE IN CONTROL BUT MOVING OFF TO THE EAST. AFTER
A COOL START, TEMPERATURES WILL MODERATE QUITE NICELY. 850MB
TEMPERATURES REACH 8-10C, WHICH SHOULD SUPPORT SURFACE
TEMPERATURES INTO THE MID 70S IN THE VALLEYS. LOTS OF SUN AS WELL.
MONDAY NIGHT: THINGS BEGIN TO CHANGE QUICKLY. A DEVELOPING STORM
OFF TO OUR WEST ASSOCIATED WITH A STRONG DIGGING TROUGH WILL TAP
INTO ABUNDANT MOISTURE DOWN IN THE SOUTHEASTERN US AND OVER THE
GULF. THAT MEANS CLOUDS WILL QUICKLY INCREASE, AND RAIN SHOULD
BEGIN TO FALL, MAINLY AFTER MIDNIGHT. WITH THE CLOUDS AND RAIN, IT
WILL BE MUCH MILDER THAN SUNDAY NIGHT, AND I WENT A BIT WARMER
THAN GFS MOS AND ALONG THE LINES OF THE 00Z ECMWF MOS GUIDANCE. IN
GENERAL, 50S TO LOW 60S FOR LOWS.
TUESDAY: GONNA BE AN INTERESTING DAY. MODELS CONTINUE TO INDICATE
A SERIOUS AMOUNT OF DYNAMICS WITH THE SYSTEM. LOOKING AT 100KTS+
AT 250MB AND EVEN A 50-60KT LOWER LEVEL JET AT 850MB. THIS WILL
NOT ONLY EASILY BRING UP ALL THAT GULF MOISTURE, BUT BE AN
EFFICIENT RAIN MAKER TOO. LATEST GUIDANCE INDICATES A WIDESPREAD 1
TO 3 INCHES OF RAIN. AT THAT AMOUNT, WE SHOULD BE FINE WITH REGARD
TO FLOOD THREAT, THOUGH SIGNIFICANT RISES WOULD OCCUR ON THE
RIVERS (ESPECIALLY IF WE SEE MORE TOTALS IN THE 3" RANGE). LATER
FORECASTS WILL MONITOR THIS THREAT.
AS MENTIONED ABOVE, WE`LL HAVE A PRETTY STRONG LOW LEVEL JET.
ALTHOUGH RIGHT NOW IT APPEARS MOST OF THAT FLOW WILL BE SOUTHERLY,
IF WE SEE THINGS TURN MORE SOUTHEASTERLY, WE`LL HAVE TO CONTEND
WITH SOME GUSTY WINDS ON THE WESTERN SLOPES OF THE GREENS. COULD
BE A LITTLE BREEZY IN THE CHAMPLAIN VALLEY THANKS TO SOME
FUNNELING OF SOUTHERLY WINDS, HOWEVER WITH ALL THE RAIN AROUND,
WE`LL HAVE A STABILIZING LAYER TO KEEP ALL THAT WIND FROM GETTING
TO THE GROUND. WENT BELOW GUIDANCE A FEW DEGREES DUE TO ALL THE
RAIN AND CLOUDS. LOTS OF PRIMARILY 60S FOR HIGHS.
INSTABILITY LOOKS MARGINAL, SO WENT PRIMARILY WITH RAIN, INSTEAD
OF SHOWERS OR THUNDER.
TUESDAY NIGHT: DEEPENING LOW PRESSURE CENTER SHOULD MOVE FROM
SOUTH TO NORTH RIGHT ACROSS THE AREA. AS IT PASSES BY TO THE NORTH
LATER AT NIGHT, WINDS WILL SWITCH TO THE WEST AND START TO PULL A
FAIRLY SIGNIFICANT COLD FRONT ACROSS THE AREA. BY DAYBREAK, WE
SHOULD HAVE A PRETTY DECENT WEST-EAST TEMPERATURE GRADIENT -- 40S
ACROSS NORTHERN NEW YORK WHILE STILL IN THE 50S IN VERMONT. RAIN
WILL TAPER OFF EARLY, BUT THEN START BACK UP AGAIN WITH THE
FRONTAL PASSAGE WITH PERHAPS SOME BRIEFLY HEAVY SHOWERS. THIS FAR
OUT, DID NOT GET CUTE -- JUST PAINTED IN LIKELY POPS FOR THE WHOLE NIGHT.
WEDNESDAY: RESIDUAL CLOUDS AND SHOWERS IN THE MORNING, OTHERWISE
CLEARING. COLD AIR ADVECTION WILL MAKE ITSELF FELT, WITH 850MB
TEMPERATURES DROPPING TO THE 2-5C RANGE BY LATE AFTERNOON. WARMEST
TEMPERATURES WILL BE IN SOUTHEASTERN VERMONT (MID 60S) WHILE
STRUGGLING TO HIT 60F IN THE ST LAWRENCE VALLEY.
THURSDAY AND FRIDAY: HIGH PRESSURE HANGS TIGHT ALONG THE EAST
COAST. SHOULD BE DRY THURSDAY, THOUGH BY FRIDAY SOME MOISTURE FROM
A SYSTEM WELL TO THE WEST MAY START TO OOZE IN, ESPECIALLY WESTERN
AREAS, DURING THE DAY. PAINTED IN LOW CHANCE POPS DUE TO
UNCERTAINTY. STAYED CLOSE TO GUIDANCE FOR TEMPERATURES, SO LOTS OF
60S THURSDAY WITH SOME MODERATION INTO THE LOWER 70S FRIDAY AS
SOUTHWEST FLOW BETWEEN THE HIGH TO THE EAST AND SYSTEM TO THE WEST
GETS ESTABLISHED.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 06Z SUNDAY...SFC COLD FRONT SWINGING THROUGH THE AREA AT
06Z TO CLEAR EAST BY 12Z. BAND OF LIGHT -SHRAS TO AFFECT VT
TERMINALS THROUGH 08Z...OTW DRY CONDS EXPECTED. VRB CIGS
ALONG/BEHIND FRONTAL BOUNDARY THROUGH 13Z WITH GENERALLY VFR
EXPECTED AT KPBG/KBTV/KRUT...OCCNL MVFR AT KMPV/KMSS...AND IFR AT
KSLK WHERE SOME PATCH -DZ AND/OR BR ALSO POSSBL. WINDS TRENDING
LIGHT TO MODERATE WEST/NORTHWESTERLY OVERNIGHT INTO
TOMORROW...WITH OCCNL GUSTS TO NEAR 20 KT IN THE 18-22Z TIME FRAME
AS CIGS TREND VFR IN ALL AREAS. SKIES TO THEN TREND SKC BY 00Z AS
WINDS ABATE TO LIGHT.
OUTLOOK 06Z SUNDAY THROUGH WEDNESDAY...
06Z SUNDAY THROUGH 00Z TUESDAY...MAINLY VFR. COULD BE LOCAL IFR IN
FOG AT KMPV/KSLK SATURDAY/SUNDAY NIGHT.
00Z TUESDAY THROUGH 12Z WEDNESDAY...MVFR AND LOCAL IFR IN PERIODS
OF RAIN.
12Z WEDNESDAY ONWARD...TRENDING TOWARD VFR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...BANACOS
SHORT TERM...WGH
LONG TERM...NASH
AVIATION...JMG/MUCCILLI
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
120 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE NORTH COUNTRY OVERNIGHT BRINGING
A CHANCE OF SHOWERS TO THE REGION. A RIDGE OF HIGH PRESSURE WILL
BUILD INTO THE REGION ON SATURDAY AND WILL REMAIN THROUGH MONDAY.
A LOW PRESSURE AREA MOVING INTO THE REGION ON TUESDAY WILL BRING
SOME HEAVY RAIN TO THE NORTH COUNTRY TUESDAY AND TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 120 AM EDT SATURDAY...MINOR UPDATE TO GOING FORECAST THIS
EARLY AM MAINLY TO ADJUST POPS FROM THE CHAMPLAIN VALLEY EASTWARD.
INITIAL PRE-FRONTAL TROUGH HAD PASSED THROUGH THE REGION WITH MAIN
COLD FRONT STILL OFF TO OUR WEST. WHAT WAS A RAGGED LINE OF
SHOWERS ACROSS NORTHERN NEW YORK HAS REDEVELOPED INTO A FAIR SHARP
LINE OF SHOWERS COMING INTO THE CHAMPLAIN VALLEY. 3KM HRRR MODEL
HAS THIS HANDLED VERY WELL...INCLUDING A BRIEF 1-2 HOUR PERIOD OF
EASTERLY WINDS AHEAD OF THE RAIN WHICH IS OCCURRING AT THE SURFACE
RIGHT NOW. HRRR HOLDS INTO HIGHER POPS EAST OF THE GREENS NOT SO
HAVE BUMPED UP A BIT FOR AT LEAST A 1 HOUR PERIOD OF LIKELY
SHOWERS. STILL NOT LOOKING AT A BUNCH OF PRECIP WITH THIS THING
THOUGH AS UPSTREAM OBS SHOWING MAINLY LESS THAN A TENTH OF AN INCH
HAS FALLEN.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS OF 433 PM EDT FRIDAY...SOME SHORTWAVES TO DROP THROUGH THE
REGION SATURDAY MORNING SO HAVE GONE WITH SLIGHT CHANCE POPS FOR
SHOWERS ACROSS THE NORTHERN ADIRONDACKS AND NORTHERN VERMONT. DEW
POINTS DROP DURING THE DAY AND BTV 4 KM MODEL NOT SHOWING ANY
SHOWER ACTIVITY DURING SATURDAY AFTERNOON. SKIES CLEARING OUT
SATURDAY NIGHT AND WILL REMAIN MOSTLY CLEAR THROUGH SUNDAY
NIGHT...AS A RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION. THERE
WILL BE A FEEL OF FALL IN THE AIR SATURDAY AND SUNDAY...AS MAX
TEMPERATURES WILL BE MAINLY IN THE 60S ON BOTH DAYS. MIN
TEMPERATURES SATURDAY NIGHT AND SUNDAY NIGHT WILL BE MAINLY IN THE
30S...WITH SOME UPPER 20S IN THE ADIRONDACKS...AND TEMPERATURES
AROUND 40 IN THE CHAMPLAIN VALLEY. EXPECTING AREAS OF FROST AROUND
THE REGION LATE SATURDAY NIGHT AND EARLY SUNDAY MORNING...AND ALSO
AGAIN LATE SUNDAY NIGHT AND EARLY MONDAY MORNING. ALSO EXPECTING
SOME RADIATION FOG TO FORM OVER THE SHELTERED FOG PRONE VALLEYS OF
EASTERN AND NORTHEAST VERMONT LATE SATURDAY NIGHT AND ALSO AGAIN
LATE SUNDAY NIGHT... AS CLEAR SKIES AND NEARLY CALM WINDS WILL
PROVIDE IDEAL CONDITIONS FOR RADIATION FOG TO FORM...MAINLY IN THE
RIVER VALLEYS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 339 PM EDT FRIDAY...LONGER RANGE GUIDANCE REMAINS IN PRETTY
DECENT AGREEMENT FOR ALL OF NEXT WEEK, SO OVERALL CONFIDENCE IN
THE FORECAST DETAILS ARE AT THE MODERATE LEVEL. DAILY DETAILS FOLLOW:
MONDAY: HIGH PRESSURE IN CONTROL BUT MOVING OFF TO THE EAST. AFTER
A COOL START, TEMPERATURES WILL MODERATE QUITE NICELY. 850MB
TEMPERATURES REACH 8-10C, WHICH SHOULD SUPPORT SURFACE
TEMPERATURES INTO THE MID 70S IN THE VALLEYS. LOTS OF SUN AS WELL.
MONDAY NIGHT: THINGS BEGIN TO CHANGE QUICKLY. A DEVELOPING STORM
OFF TO OUR WEST ASSOCIATED WITH A STRONG DIGGING TROUGH WILL TAP
INTO ABUNDANT MOISTURE DOWN IN THE SOUTHEASTERN US AND OVER THE
GULF. THAT MEANS CLOUDS WILL QUICKLY INCREASE, AND RAIN SHOULD
BEGIN TO FALL, MAINLY AFTER MIDNIGHT. WITH THE CLOUDS AND RAIN, IT
WILL BE MUCH MILDER THAN SUNDAY NIGHT, AND I WENT A BIT WARMER
THAN GFS MOS AND ALONG THE LINES OF THE 00Z ECMWF MOS GUIDANCE. IN
GENERAL, 50S TO LOW 60S FOR LOWS.
TUESDAY: GONNA BE AN INTERESTING DAY. MODELS CONTINUE TO INDICATE
A SERIOUS AMOUNT OF DYNAMICS WITH THE SYSTEM. LOOKING AT 100KTS+
AT 250MB AND EVEN A 50-60KT LOWER LEVEL JET AT 850MB. THIS WILL
NOT ONLY EASILY BRING UP ALL THAT GULF MOISTURE, BUT BE AN
EFFICIENT RAIN MAKER TOO. LATEST GUIDANCE INDICATES A WIDESPREAD 1
TO 3 INCHES OF RAIN. AT THAT AMOUNT, WE SHOULD BE FINE WITH REGARD
TO FLOOD THREAT, THOUGH SIGNIFICANT RISES WOULD OCCUR ON THE
RIVERS (ESPECIALLY IF WE SEE MORE TOTALS IN THE 3" RANGE). LATER
FORECASTS WILL MONITOR THIS THREAT.
AS MENTIONED ABOVE, WE`LL HAVE A PRETTY STRONG LOW LEVEL JET.
ALTHOUGH RIGHT NOW IT APPEARS MOST OF THAT FLOW WILL BE SOUTHERLY,
IF WE SEE THINGS TURN MORE SOUTHEASTERLY, WE`LL HAVE TO CONTEND
WITH SOME GUSTY WINDS ON THE WESTERN SLOPES OF THE GREENS. COULD
BE A LITTLE BREEZY IN THE CHAMPLAIN VALLEY THANKS TO SOME
FUNNELING OF SOUTHERLY WINDS, HOWEVER WITH ALL THE RAIN AROUND,
WE`LL HAVE A STABILIZING LAYER TO KEEP ALL THAT WIND FROM GETTING
TO THE GROUND. WENT BELOW GUIDANCE A FEW DEGREES DUE TO ALL THE
RAIN AND CLOUDS. LOTS OF PRIMARILY 60S FOR HIGHS.
INSTABILITY LOOKS MARGINAL, SO WENT PRIMARILY WITH RAIN, INSTEAD
OF SHOWERS OR THUNDER.
TUESDAY NIGHT: DEEPENING LOW PRESSURE CENTER SHOULD MOVE FROM
SOUTH TO NORTH RIGHT ACROSS THE AREA. AS IT PASSES BY TO THE NORTH
LATER AT NIGHT, WINDS WILL SWITCH TO THE WEST AND START TO PULL A
FAIRLY SIGNIFICANT COLD FRONT ACROSS THE AREA. BY DAYBREAK, WE
SHOULD HAVE A PRETTY DECENT WEST-EAST TEMPERATURE GRADIENT -- 40S
ACROSS NORTHERN NEW YORK WHILE STILL IN THE 50S IN VERMONT. RAIN
WILL TAPER OFF EARLY, BUT THEN START BACK UP AGAIN WITH THE
FRONTAL PASSAGE WITH PERHAPS SOME BRIEFLY HEAVY SHOWERS. THIS FAR
OUT, DID NOT GET CUTE -- JUST PAINTED IN LIKELY POPS FOR THE WHOLE NIGHT.
WEDNESDAY: RESIDUAL CLOUDS AND SHOWERS IN THE MORNING, OTHERWISE
CLEARING. COLD AIR ADVECTION WILL MAKE ITSELF FELT, WITH 850MB
TEMPERATURES DROPPING TO THE 2-5C RANGE BY LATE AFTERNOON. WARMEST
TEMPERATURES WILL BE IN SOUTHEASTERN VERMONT (MID 60S) WHILE
STRUGGLING TO HIT 60F IN THE ST LAWRENCE VALLEY.
THURSDAY AND FRIDAY: HIGH PRESSURE HANGS TIGHT ALONG THE EAST
COAST. SHOULD BE DRY THURSDAY, THOUGH BY FRIDAY SOME MOISTURE FROM
A SYSTEM WELL TO THE WEST MAY START TO OOZE IN, ESPECIALLY WESTERN
AREAS, DURING THE DAY. PAINTED IN LOW CHANCE POPS DUE TO
UNCERTAINTY. STAYED CLOSE TO GUIDANCE FOR TEMPERATURES, SO LOTS OF
60S THURSDAY WITH SOME MODERATION INTO THE LOWER 70S FRIDAY AS
SOUTHWEST FLOW BETWEEN THE HIGH TO THE EAST AND SYSTEM TO THE WEST
GETS ESTABLISHED.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 00Z SUNDAY...AREA OF SHOWERS AND LOW CLOUDS WILL CREATE
VFR/MVFR CONDITIONS THIS EVENING AND TONIGHT...TRENDING TO
ALL VFR ON SATURDAY. PERIODS OF SHOWERS AND POSSIBLE THUNDERSTORMS
ASSOCIATED WITH A COLD FRONT WILL PUSH THROUGH MSS/SLK THROUGH THE
EVENING WITH REDUCED VISIBILITIES AND CEILINGS. THIS ACTIVITY WILL
GRADUALLY WEAKEN AND TAPER TO MORE SCATTERED SHOWERS AS IT ENTERS
THE CHAMPLAIN VALLEY AND VERMONT. ACCOMPANYING AND FOLLOWING THIS
COLD FRONT IS AN AREA OF LOWER CLOUDS...WHICH WILL REDUCE CEILINGS
TO 1500-3000 FEET FOR A PERIOD OVERNIGHT AT ALL TAF SITES. THIS
SHOULD GRADUALLY LIFT SATURDAY MORNING AND BECOME A BROKEN DECK OF
STRATOCUMULUS WITH CEILINGS GENERALLY 3-5K FEET. EVEN WITH
RAINFALL...NOT EXPECTING MUCH IF ANY FOG TONIGHT WITH INCREASED LOW
LEVEL WIND FIELD AND FALLING DEW POINTS FOLLOWING FRONTAL PASSAGE.
WINDS TONIGHT WILL TURN FROM THE SOUTH AHEAD OF THE COLD FRONT TO
WEST/NORTHWEST BEHIND...GENERALLY 5-10 KNOTS WITH SOME GUSTS UP TO
20 KNOTS FOLLOWING PASSAGE. ON SATURDAY...WINDS REMAIN WEST-
NORTHWESTERLY 10-15 KNOTS.
OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY...
00Z SUNDAY THROUGH 00Z TUESDAY...MAINLY VFR. COULD BE LOCAL IFR
IN FOG AT KMPV/KSLK SATURDAY/SUNDAY NIGHT.
00Z TUESDAY THROUGH 12Z WEDNESDAY...MVFR AND LOCAL IFR IN PERIODS
OF RAIN.
12Z WEDNESDAY ONWARD...TRENDING TOWARD VFR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...BANACOS
SHORT TERM...WGH
LONG TERM...NASH
AVIATION...MUCCILLI/NASH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
209 PM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SOUTH OF THE REGION TODAY. HIGH
PRESSURE WILL BUILD OVER THE AREA TONIGHT INTO SUNDAY THEN MOVE
OFFSHORE SUNDAY NIGHT. LOW PRESSURE WILL MOVE NORTH FROM THE GULF
COAST REGION MONDAY AND ACROSS WESTERN NORTH CAROLINA MONDAY
NIGHT. A COLD FRONT WILL MOVE ACROSS THE REGION TUESDAY NIGHT
FOLLOWED BY HIGH PRESSURE BUILDING IN FROM THE NORTHWEST LATE
WEDNESDAY INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1 PM SATURDAY...LATEST RAP MODEL RUNS CONTINUE TO INDICATE
THAT THE REMAINDER OF THE DAY WILL BE DRY. NAM DOES SHOW SOME
LIGHT QPF MOVING FROM NORTH TO SOUTH ACROSS THE PAMLICO
SOUND...BUT LITTLE EVIDENCE IN SATELLITE OF THAT AT THIS TIME AND
WILL LEAVE OUT OF FORECAST. NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
AS OF 215 AM SATURDAY...HIGH PRES WILL BUILD IN FROM THE N WITH
DRY WX EXPECTED. AS WINDS GO LIGHT INLAND WILL AGAIN HAVE THE
THREAT FOR SOME PATCHY FOG LATE. LOWS WILL RANGE FROM THE UPR 50S
COOLER INLAND SPOTS TO MID/UPR 60S BEACHES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 315 AM SAT...MODELS ARE ALL IN GENERAL GOOD AGREEMENT
THROUGH THE PERIOD UNTIL MID WEEK WHEN THERE ARE MINOR TIMING
DIFFERENCES WITH THE COLD FRONT PUSHING OFF THE COAST ON WED.
GENERALLY FOLLOWED A BLEND OF MODEL GUIDANCE FOR MAJOR FEATURES.
FOLLOWED CLOSE TO MOS BIAS CORRECTED GUIDANCE FOR TEMPS THROUGH
THE PERIOD...WHICH WILL BE PRETTY CLOSE TO CLIMATOLOGY VALUES. MAD
ONLY MINOT POP ADJUSTMENTS THROUGH THE PERIOD. GENERALLY JUST A
SLIGHT CHANCE OF A SHOWER THROUGH SUNDAY INTO SUNDAY NIGHT...WITH
A GRADUAL INCREASE IN POPS ON MONDAY. THE BEST CHANCE OF SHOWERS
AND THUNDERSTORMS WILL COME ON TUESDAY AHEAD OF THE APPROACHING
COLD FRONT. COULD SEE SOME STRONG THUNDERSTORMS BUT CONFIDENCE IN
TIMING AND INSTABILITY IS TOO LOW AT THIS POINT TO GIVE E
DEFINITIVE CHANCE OF SEVERE STORMS. THE ECMWF DRIES THINGS OUT
DEFINITIVELY ON WEDNESDAY...BUT GFS IS A BIT SLOWER TO CLEAR
THINGS OUT COMPLETELY ALONG THE COAST...THEREFORE CONTINUED TO
CARRY SLIGHT CHANCE POPS THROUGH THE DAY WEDNESDAY BEFORE DRYING
THINGS OUT THURSDAY AND FRIDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 2 PM SATURDAY...VFR CONDITIONS ARE EXPECTED FOR ALL TAF SITES
UNTIL LATE TONIGHT. AS HIGH PRESSURE CONTINUES TO BUILD IN FROM
THE NW AND WITH WINDS EXPECTED TO DECOUPLE...THERE IS A GOOD
CHANCE OF FOG FORMATION AFTER 6Z. MOS GUIDANCE HAS INDICATED LIFR
TO VLIFR CONDITIONS...BUT FOR NOW WILL BE CONSERVATIVE TO FORECAST
LIFR CONDITIONS TO ALL TAF SITES. WOULD NOT BE A SURPRISE IF CONDITIONS
DROP EVEN LOWER. ANY FOG FORMATION THAT DEVELOPS...WILL START TO
LIFT OUT BY 12Z.
LONG TERM /SUNDAY THROUGH WED/...
AS OF 2 PM SAT...VFR CONDITIONS WILL CONTINUE FOR SUNDAY ALTHOUGH
CAN`T RULE OUT A STRAY SHOWER SUNDAY NIGHT. AS LOW PRESSURE SYS
APPROACHES TE AREA...THERE IS AN INCREASE CHANCE OF SCATTERED SHOWERS FOR
MONDAY...SO MVFR CONDITIONS CAN BE EXPECTED. BY TUESDAY MORE
WIDESPREAD SHOWERS AND TSTMS WILL MOVE INTO THE AREA AHEAD OF A
COLD FRONT. MVFR CONDITIONS WILL BE PREDOMINATE WITH PERIODS OF
IFR POSSIBLE OCCASIONALLY. CONDITIONS SHOULD BEGIN TO IMPROVE
BEHIND THE FRONT ON WEDNESDAY.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1 PM SATURDAY...A BIT OF AN UPTICK IN WIND SPEEDS OVER THE
NORTHERN WATERS WITH DUCK GUSTING TO 23 KNOTS AND OREGON INLET TO
19 KNOTS...SO HAVE INCREASED WINDS A HAIR IN THESE MARINE ZONES.
OTHERWISE...NW/NNW WINDS OF 10 TO 15 KNOTS ARE EXPECTED THROUGH
THIS AFTERNOON WITH SEAS OF 2 TO 4 FEET BUILDING TO 3 TO 5 FEET
LATE. OF INTEREST WILL BE DEVELOPMENT OF LONG PERIOD SWELLS BY
THIS EVENING. CURRENT OBSERVATIONS STILL SHOWING ABOUT 8 SECOND
PERIODS...BUT THESE ARE FORECAST TO INCREASE TO 15 SECONDS OR
GREATER BY EVENING. THIS WILL LEAD TO ROUGH SURF AND AN INCREASED
THREAT OF RIP CURRENTS. N TO NE WINDS WILL CONT AT MAINLY 10 TO 15
KTS TONIGHT AS HIGH PRES BUILDS IN FROM THE N...COULD BE SOME
GUSTS TO 20 KT EARLY ESPCLY CNTRL AND NRN WTRS.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 315 AM SAT...AS MENTIONED IN LONG TERM DISCUSSION NO
SIGNIFICANT MODEL DIFFERENCES THROUGH THE PERIOD. THERE IS JUST A
MINOR TIMING DIFFERENCE WITH THE COLD FRONT MOVING THROUGH THE
REGION WEDNESDAY. FOLLOWED A BLEND OF GFS/ECMWF FOR WINDS IN THAT
TIME PERIOD. EARLY IN THE PERIOD SCA CONDITIONS DUE MAINLY TO THE
LONG PERIOD SWELL WILL BEGIN TO DIMINISH. SEAS WILL FALL BELOW SCA
CONDITIONS ALL WATERS BY LATE SUNDAY AFTERNOON. THE LULL IN CALM
CONDITIONS WILL BE SHORT ON MONDAY AS WINDS BECOME SOUTHERLY INCREASE
TO 20 TO 25 KT AHEAD OF THE APPROACHING COLD FRONT ON
TUESDAY...WITH SEAS BUILDING TO 6 TO 7 FEET ACROSS A LARGE PORTION
OF THE WATERS. THE COLD FRONT SHOULD PASS THROUGH THE WATERS
WEDNESDAY WITH SEAS SUBSIDING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ103.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 PM EDT
SUNDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 1 PM EDT
SUNDAY FOR AMZ150-156-158.
&&
$$
SYNOPSIS...RF
NEAR TERM...CTC
SHORT TERM...RF
LONG TERM...RSB
AVIATION...BM/RSB
MARINE...RSB/CTC/RF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
105 PM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DRIFT SOUTH TODAY AND DISSIPATE OVER THE AREA
SUNDAY. LOW PRESSURE DEVELOPING ALONG THE GULF COAST MONDAY WILL
MOVE THROUGH THE WESTERN CAROLINAS TUESDAY...BRINGING PERIODS OF
SHOWERS AND THUNDERSTORMS TO THE AREA...WITH LOCALLY HEAVY RAIN
POSSIBLE. A COLD FRONT WILL CROSS THE AREA EARLY WEDNESDAY...WITH
HIGH PRESSURE BUILDING IN BEHIND IT CREATING COOLER AND DRIER
WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM SATURDAY...ADJUSTED SHOWER CHANCES DOWN JUST A TAD
FROM NOW THROUGH 6 PM. ALTHOUGH THE CUMULUS FIELD IS AS EXPANSIVE AS
THOUGHT...THE VERTICAL EXTENT OF THE CUMULUS IS NOT AS GREAT AS
EXPECTED. THIS MAY CHANGE WITH ADDITIONAL HEATING THROUGH THE
AFTERNOON BUT LATEST MESOSCALE MODELS CONTINUE TO SHOW LITTLE
CONVECTIVE PRECIPITATION THROUGH THE AFTERNOON. PREVIOUS DISCUSSION
FROM 1000 AM FOLLOWS...
FOG HAS LIFTED ACROSS THE EASTERN CAROLINAS BUT STUBBORN LOW CLOUDS
IN THE SC PEE DEE REGION MAY TAKE ANOTHER 30 MINUTES OR SO TO BURN
OFF. MOSTLY SUNNY SKIES LATE THIS MORNING WILL TURN PARTLY CLOUDY
ACROSS MOST OF OUR AREA THIS AFTERNOON AS FAIRLY STEEP LOW-LEVEL
LAPSE RATES AND GOOD MOISTURE CONTENT BELOW 850 MB HELP PRODUCE A
CUMULUS CLOUD FIELD. THE 12Z CHS SOUNDING SHOWED THE 06Z GFS AND NAM
MODELS WERE BOTH 5 DEGREES F TOO DRY WITH DEWPOINTS FROM THE SURFACE
UP THROUGH 850 MB. THIS ADDITIONAL MOISTURE SHOULD HELP ENHANCE THE
AFTERNOON CUMULUS.
THE BIGGEST QUESTION MARK WITH TODAY`S FORECAST IS THE POTENTIAL OF
AFTERNOON AND EVENING SHOWERS. THE 06Z GFS AND NAM MODELS PRODUCE
SOME ISOLATED SHOWERS BUT THE ASSOCIATED STATISTICAL OUTPUT SHOWS
ONLY 0-10 PERCENT POPS. THE PAST SEVERAL HRRR RUNS ALSO SHOW DRY
WEATHER THROUGH THIS EVENING. GIVEN FAIRLY MOIST LOW-LEVELS AND
STEEP LAPSE RATES UP THROUGH AN INVERSION AT 10-11 KFT I EXPECT AT
LEAST SOME ISOLATED SHOWERS MUCH LIKE EXPERIENCED YESTERDAY. THE
SEABREEZE BOUNDARY...PARTICULARLY IN SE NORTH CAROLINA WHERE NATURAL
CONVERGENCE IS PRODUCED BY THE SEABREEZE...IS AN OBVIOUSLY TRIGGER.
A SECOND POSSIBLE TRIGGER IS THE ARRIVAL OF A DYING COLD FRONT FROM
THE NORTH LATE THIS AFTERNOON...ALTHOUGH CONVERGENCE IS WEAKENING
WITH THIS FEATURE GIVEN THE INCREASINGLY SIMILAR WIND DIRECTIONS ON
EITHER SIDE. IN ANY CASE WE`LL KEEP POPS NO HIGHER THAN 25% THROUGH
THIS EVENING.
HIGHS TODAY SHOULD REACH THE MID 80S AWAY FROM THE OCEAN...WITH
HIGHS AROUND 80 ON THE BEACHES. MORNING LOW CLOUDS AND FOG SHOULD
HAVE NO IMPACT ON THESE TEMPERATURES.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SHORT TERM WILL FEATURE A TRANSITIONAL
PERIOD AS SPLIT FLOW 500MB PATTERN TRANSITIONS TO A HIGHLY AMPLIFIED
TROUGH ACROSS THE EASTERN HALF OF THE COUNTRY. HIGH PRESSURE
DRIFTING ACROSS THE MID ATLANTIC SUNDAY WILL ALLOW WINDS TO TURN
GRADUALLY FROM NE TO SE THROUGH THE DAY. THIS OCCURS AT THE SAME
TIME THAT A 60KT 300MB JET MAX MOVES ACROSS NC. EVEN THOUGH FORECAST
SOUNDINGS REMAIN RELATIVELY DRY ABOVE 850MB...THE INCREASING
MOISTURE ON SE FLOW COMBINED WITH THE SUBTLE UPPER SUPPORT COULD
SPAWN AN ISOLATED SHOWER/TSTM DURING THE AFTN...AND WILL KEEP
INHERITED SCHC POP. TEMPS SUNDAY WILL BE RIGHT AROUND CLIMO...LOW TO
MID 80S MOST LOCATIONS. MINS WILL FALL TO RIGHT AROUND CLIMO SUNDAY
NIGHT...MID 60S.
SOUTHERN STREAM VORT MAX WILL GET STRUNG OUT AND LIFT NORTHEAST AS A
DEEP 500MB TROUGH DIGS ACROSS THE CENTRAL PLAINS. WAVE OF LOW
PRESSURE DEVELOPS BENEATH THIS UPPER VORT AND SLIDES NORTHEAST
TOWARDS THE AREA...PUSHING A WARM FRONT ACROSS THE CAROLINAS DURING
MONDAY. AS THIS OCCURS...FLOW WITHIN THE COLUMN TURNS TO BECOME DEEP
SOUTHEASTERLY...ADVECTING SIGNIFICANTLY INCREASED MOISTURE INTO THE
CAROLINAS. ALTHOUGH BEST RAIN CHANCES WILL HOLD OFF UNTIL MONDAY
NIGHT...WILL SHOW INCREASING POP THROUGH THE DAY FROM SOUTH TO
NORTH. WITH PWATS RISING TO NEARLY TWO INCHES MONDAY NIGHT...AND
FORCING INCREASING LATE...EXPECT A PERIOD OF MDT/HEAVY RAINFALL
DEVELOPING AT THE END OF THE PERIOD...AND WILL BUMP ALL LOCATIONS TO
LIKELY POP. TEMPS WILL BE TEMPERED BY CLOUDS/RAIN...REMAINING IN THE
LOW 80S. INCREASED SOUTHERLY FLOW AND RAIN WILL KEEP MINS WELL ABOVE
CLIMO...ONLY FALLING TO AROUND 70.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...A VERY WET TUESDAY EXPECTED BEFORE DRIER AND
COOLER WEATHER DEVELOPS FOR THE LATTER HALF OF THE UPCOMING WEEK.
INGREDIENTS APPEAR TO BE COMING TOGETHER TO SUPPORT A VERY WET
TUESDAY WITH MODERATE/HEAVY RAINFALL LIKELY ACROSS THE ENTIRE CWA.
SOUTHERN STREAM VORT MAX BEGINS TO PHASE WITH NORTHERN STREAM ENERGY
JUST WEST OF THE CWA. AS THIS OCCURS...SURFACE LOW WORKS UP ALONG
THE APPALACHIANS ACROSS THE WESTERN CAROLINAS. THE KEEPS THE CWA IN
DEEP SOUTHERLY FLOW WHICH ADVECTS A STRONG THETA-E RIDGE INTO THE
AREA. PWATS RISE TO NEARLY 2.25 INCHES...OR 2-3 SD`S ABOVE NORMAL
FOR MID-SEPTEMBER. AT THE SAME TIME...WE ENTER THE RIGHT DIFFLUENT
PORTION OF AN 80-90KT 300MB JET AND 850MB TRANSPORT WINDS APPROACH
40-50 KTS. THIS ALL POINTS TOWARDS PERIODS OF HEAVY RAINFALL...AND
HPC IS PAINTING 1-1.5" OF QPF ACROSS THIS AREA. WITH SUCH STRONG LOW
LEVEL WINDS IN PLACE...COULD BE CONCERNED ABOUT A SEVERE WIND
POTENTIAL...HOWEVER...LACK OF INSOLATION KEEPS ML LAPSE RATES BELOW
6C/KM...SO HEAVY RAIN EXPECTED TO BE THE PRIMARY THREAT. RAIN WILL
CONTINUE THROUGH TUESDAY NIGHT BEFORE LOW MOVES OFF TO THE NORTHEAST
AND ITS ASSOCIATED COLD FRONT DRAGS THROUGH BY EARLY WEDNESDAY.
BEHIND THIS FRONT...COOLER AND DRIER WEATHER EXPECTED THROUGH THE
REST OF THE EXTENDED. HIGH PRESSURE BUILDS DOWN THE COAST AS 500MB
TROUGH RELOADS ACROSS THE MIDWEST. THIS WILL BRING COOL E/NE LOW
LEVEL FLOW...BUT ALSO MOSTLY SUNNY AND DRY CONDITIONS TO FINISH THE
WEEK.
TEMPS TUESDAY WILL BE AROUND CLIMO WITH CLOUDS AND RAIN...FALLING TO
BELOW CLIMO FOR THE REST OF THE WEEK BEHIND THE COLD FRONT. MINS
TUESDAY NIGHT WILL BE ABOVE CLIMO...BEFORE FALLING TO NEAR NORMAL
WED-FRI.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...VFR CONDITIONS THROUGH THE EVENING HOURS WITH SCATTERED
CUMULUS. A STRAY SHOWER IS POSSIBLE ALONG THE SEA BREEZE BOUNDARY...
BUT WILL BE VERY ISOLATED IN NATURE NOT WARRANTING A VCSH MENTION.
TONIGHT...MOISTURE WILL POOL ALONG THE STALLING FRONTAL BOUNDARY.
THINK MID AND HIGH CLOUDS WILL STILL BE SCATTERED ENOUGH TO SUPPORT
RADIATIONAL COOLING WITH FOG/STRATUS AFTER 09Z. SUNDAY MORNING...
MOISTURE CONTINUES TO BE ON THE INCREASE WITH SOME ISENTROPIC LIFT
DEVELOPING...PARTICULARLY IN THE LBT VICINITY. SCATTERED
SHOWERS/T-STORMS ARE POSSIBLE SUNDAY AFTERNOON.
THE EXTENDED OUTLOOK...MOISTURE WILL CONTINUE TO BE ON THE INCREASE
WITH SCATTERED CONVECTION SUNDAY EVENING THROUGH MONDAY...BECOMING
NUMEROUS ON TUESDAY WITH MODERATE CONFIDENCE FOR INTERMITTENT IFR
CONDITIONS. BECOMING VFR WEDNESDAY THROUGH THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM SATURDAY...NO CHANGES TO THE FORECAST ARE NEEDED. THE
SEABREEZE IS JUST NOW BEGINNING TO SHOW UP IN MESONET WIND
OBSERVATIONS AT THE BEACHES. PREVIOUS DISCUSSION FROM 1000 AM
FOLLOWS...
A SURFACE COLD FRONT OVER NORTHERN NORTH CAROLINA WILL MOVE SOUTH TO
CAPE FEAR LATE THIS AFTERNOON. WINDS ON BOTH SIDES OF THE BOUNDARY
ARE NORTHERLY SO THE FEATURE IS CERTAINLY LOSING ITS DEFINITION AS
IT MOVES SOUTH. UNLESS THERE IS A LINE OF CLOUDS OR SHOWERS
ACCOMPANYING THE FRONT...THE ONLY IMPACT MARINERS SHOULD NOTE AS THE
FRONT REACHES US IS A VEERING OF THE WIND DIRECTION A LITTLE MORE
EASTERLY. OTHERWISE NORTH-NORTHEASTERLY WINDS AROUND 10 KT WILL
CONTINUE THROUGH THE DAY...TURNING EAST TO EVEN SOUTHEAST ALONG THE
IMMEDIATE COAST AS A WEAK SEABREEZE DEVELOPS. SEA HEIGHTS AT THE
BUOYS ARE 3-4 FT LIKE YESTERDAY...BUT SPECTRAL WAVE DATA LOOKS VERY
DIFFERENT THAN YESTERDAY WITH VERY LITTLE SHORT PERIOD WAVE ENERGY
PRESENT. THE DOMINANT PERIOD IS NOW 9-10 SECONDS IN AN EASTERLY
SWELL THAT SHOULD PERSIST THROUGH TONIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE DRIFTING ACROSS THE
MID-ATLANTIC STATES WILL KEEP WINDS LIGHT SUNDAY...AS THEY VEER
SLOWLY FROM THE NE EARLY...TO SE BY NIGHT. SEAS SUNDAY WILL FALL
SLOWLY THROUGH THE DAY...FROM 3-4 FT EARLY TO 2-4 FT LATE...FORMED
BY A COMBINATION OF AN EASTERLY WIND WAVE AND A 2-3 FT/12SEC SE
SWELL FROM HURRICANE NADINE. CONDITIONS ACROSS THE WATERS WILL
DETERIORATE MONDAY AS A STORM SYSTEM PASSES WEST OF THE AREA. A
WARM FRONT WILL CROSS THE WATERS DURING MONDAY...TURNING WINDS TO
THE SOUTH...WHICH WILL THEN INCREASE DRAMATICALLY MONDAY NIGHT.
WINDS LESS THAN 10 KTS EARLY MONDAY WILL RISE UP TO 15-20 KTS
MONDAY NIGHT. ALTHOUGH THE LONG PERIOD SWELL WILL DECAY AS
HURRICANE NADINE PULLS AWAY...THIS INCREASING WIND WILL FORCE
STEEPER WAVES...AND SEAS WILL BUILD TO 3-5 FT BY THE END OF THE
PERIOD...WITH ISOLATED 6 FTERS POSSIBLE. AT THIS TIME IT APPEARS A
SCEC WILL BE NEEDED MONDAY NIGHT...WITH AN SCA POSSIBLE.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...STRONG SOUTHERLY WINDS TUESDAY CREATE
HAZARDOUS CONDITIONS ACROSS THE COASTAL WATERS...WITH A SMALL CRAFT
ADVISORY LIKELY NEEDED MUCH OF THE DAY. SOUTHERLY WINDS AHEAD OF A
COLD FRONT WILL BE 15-20 KTS...POSSIBLY HIGHER...AND HELP BUILD SEAS
TO 4-6 FT. THESE WAVES WILL BE QUITE STEEP AS WELL...WITH A DOMINANT
PERIOD OF 5-6 SECONDS. VERY LATE TUESDAY NIGHT THE COLD FRONT WILL
CROSS THE WATERS...TURNING WINDS TO THE NW...THEN NE ON WEDNESDAY
WHILE SPEEDS DECREASE TO 10-15 KTS. SEAS FALL QUICKLY...BECOMING 2-3
FT THROUGH MUCH OF WEDNESDAY...ALTHOUGH A CONFUSED SEA STATE IS
LIKELY EARLY WEDNESDAY DUE TO SEVERAL DIFFERENT WAVE GROUPS PRESENT
IN THE SPECTRUM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...43/TRA
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
104 PM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SOUTH OF THE REGION TODAY. HIGH
PRESSURE WILL BUILD OVER THE AREA TONIGHT INTO SUNDAY THEN MOVE
OFFSHORE SUNDAY NIGHT. LOW PRESSURE WILL MOVE NORTH FROM THE GULF
COAST REGION MONDAY AND ACROSS WESTERN NORTH CAROLINA MONDAY
NIGHT. A COLD FRONT WILL MOVE ACROSS THE REGION TUESDAY NIGHT
FOLLOWED BY HIGH PRESSURE BUILDING IN FROM THE NORTHWEST LATE
WEDNESDAY INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1 PM SATURDAY...LATEST RAP MODEL RUNS CONTINUE TO INDICATE
THAT THE REMAINDER OF THE DAY WILL BE DRY. NAM DOES SHOW SOME
LIGHT QPF MOVING FROM NORTH TO SOUTH ACROSS THE PAMLICO
SOUND...BUT LITTLE EVIDENCE IN SATELLITE OF THAT AT THIS TIME AND
WILL LEAVE OUT OF FORECAST. NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
AS OF 215 AM SATURDAY...HIGH PRES WILL BUILD IN FROM THE N WITH
DRY WX EXPECTED. AS WINDS GO LIGHT INLAND WILL AGAIN HAVE THE
THREAT FOR SOME PATCHY FOG LATE. LOWS WILL RANGE FROM THE UPR 50S
COOLER INLAND SPOTS TO MID/UPR 60S BEACHES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 315 AM SAT...MODELS ARE ALL IN GENERAL GOOD AGREEMENT
THROUGH THE PERIOD UNTIL MID WEEK WHEN THERE ARE MINOR TIMING
DIFFERENCES WITH THE COLD FRONT PUSHING OFF THE COAST ON WED.
GENERALLY FOLLOWED A BLEND OF MODEL GUIDANCE FOR MAJOR FEATURES.
FOLLOWED CLOSE TO MOS BIAS CORRECTED GUIDANCE FOR TEMPS THROUGH
THE PERIOD...WHICH WILL BE PRETTY CLOSE TO CLIMATOLOGY VALUES. MAD
ONLY MINOT POP ADJUSTMENTS THROUGH THE PERIOD. GENERALLY JUST A
SLIGHT CHANCE OF A SHOWER THROUGH SUNDAY INTO SUNDAY NIGHT...WITH
A GRADUAL INCREASE IN POPS ON MONDAY. THE BEST CHANCE OF SHOWERS
AND THUNDERSTORMS WILL COME ON TUESDAY AHEAD OF THE APPROACHING
COLD FRONT. COULD SEE SOME STRONG THUNDERSTORMS BUT CONFIDENCE IN
TIMING AND INSTABILITY IS TOO LOW AT THIS POINT TO GIVE E
DEFINITIVE CHANCE OF SEVERE STORMS. THE ECMWF DRIES THINGS OUT
DEFINITIVELY ON WEDNESDAY...BUT GFS IS A BIT SLOWER TO CLEAR
THINGS OUT COMPLETELY ALONG THE COAST...THEREFORE CONTINUED TO
CARRY SLIGHT CHANCE POPS THROUGH THE DAY WEDNESDAY BEFORE DRYING
THINGS OUT THURSDAY AND FRIDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 615 AM SATURDAY...WIDESPREAD LIFR IN FOG/ST EARLY THIS
MORN. CONDITIONS SHLD BEGIN TO IMPROVE AROUND 12Z AS WEAK COLD
FRONT DROPS INTO REGION AND MIXING STARTS. ONCE FOG LIFTS EXPECT
VFR REST OF THE DAY WITH POSS SOME ISOLD SHRA NEAR CST LATE. AS
HIGH PRES BUILDS IN FROM THE N TONIGHT WILL AGAIN HAVE THE THREAT
FOR SOME PATCHY FOG AND IFR CONDITIONS AT TIMES MAINLY AFT 08Z.
LONG TERM /SUNDAY THROUGH WED/...
AS OF 315 AM SAT...VFR CONDITIONS PREVAIL THROUGH SUNDAY INTO
SUNDAY NIGHT ALTHOUGH CAN`T RULE OUT A STRAY SHOWER SUNDAY NIGHT.
THE CHANCE FOR SCATTERED SHOWERS WILL INCREASE INTO MONDAY AND
MONDAY NIGHT...BUT WOULD EXPECT MOSTLY MVFR CONDITIONS. BY TUESDAY
MORE WIDESPREAD SHOWERS AND TSTMS WILL MOVE INTO THE AREA AHEAD OF
A COLD FRONT. MVFR CONDITIONS WILL BE PREDOMINATE WITH PERIODS OF
IFR POSSIBLE OCCASIONALLY. CONDITIONS SHOULD BEGIN TO IMPROVE
BEHIND THE FRONT ON WEDNESDAY.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1 PM SATURDAY...A BIT OF AN UPTICK IN WIND SPEEDS OVER THE
NORTHERN WATERS WITH DUCK GUSTING TO 23 KNOTS AND OREGON INLET TO
19 KNOTS...SO HAVE INCREASED WINDS A HAIR IN THESE MARINE ZONES.
OTHERWISE...NW/NNW WINDS OF 10 TO 15 KNOTS ARE EXPECTED THROUGH
THIS AFTERNOON WITH SEAS OF 2 TO 4 FEET BUILDING TO 3 TO 5 FEET
LATE. OF INTEREST WILL BE DEVELOPMENT OF LONG PERIOD SWELLS BY
THIS EVENING. CURRENT OBSERVATIONS STILL SHOWING ABOUT 8 SECOND
PERIODS...BUT THESE ARE FORECAST TO INCREASE TO 15 SECONDS OR
GREATER BY EVENING. THIS WILL LEAD TO ROUGH SURF AND AN INCREASED
THREAT OF RIP CURRENTS. N TO NE WINDS WILL CONT AT MAINLY 10 TO 15
KTS TONIGHT AS HIGH PRES BUILDS IN FROM THE N...COULD BE SOME
GUSTS TO 20 KT EARLY ESPCLY CNTRL AND NRN WTRS.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 315 AM SAT...AS MENTIONED IN LONG TERM DISCUSSION NO
SIGNIFICANT MODEL DIFFERENCES THROUGH THE PERIOD. THERE IS JUST A
MINOR TIMING DIFFERENCE WITH THE COLD FRONT MOVING THROUGH THE
REGION WEDNESDAY. FOLLOWED A BLEND OF GFS/ECMWF FOR WINDS IN THAT
TIME PERIOD. EARLY IN THE PERIOD SCA CONDITIONS DUE MAINLY TO THE
LONG PERIOD SWELL WILL BEGIN TO DIMINISH. SEAS WILL FALL BELOW SCA
CONDITIONS ALL WATERS BY LATE SUNDAY AFTERNOON. THE LULL IN CALM
CONDITIONS WILL BE SHORT ON MONDAY AS WINDS BECOME SOUTHERLY INCREASE
TO 20 TO 25 KT AHEAD OF THE APPROACHING COLD FRONT ON
TUESDAY...WITH SEAS BUILDING TO 6 TO 7 FEET ACROSS A LARGE PORTION
OF THE WATERS. THE COLD FRONT SHOULD PASS THROUGH THE WATERS
WEDNESDAY WITH SEAS SUBSIDING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ103.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 PM EDT
SUNDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 1 PM EDT
SUNDAY FOR AMZ150-156-158.
&&
$$
SYNOPSIS...RF
NEAR TERM...CTC
SHORT TERM...RF
LONG TERM...RSB
AVIATION...RSB/RF
MARINE...RSB/CTC/RF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1030 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DRIFT SOUTH TODAY AND DISSIPATE OVER THE AREA
SUNDAY. LOW PRESSURE DEVELOPING ALONG THE GULF COAST MONDAY WILL
MOVE THROUGH THE WESTERN CAROLINAS TUESDAY...BRINGING PERIODS OF
SHOWERS AND THUNDERSTORMS TO THE AREA...WITH LOCALLY HEAVY RAIN
POSSIBLE. A COLD FRONT WILL CROSS THE AREA EARLY WEDNESDAY...WITH
HIGH PRESSURE BUILDING IN BEHIND IT CREATING COOLER AND DRIER
WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...FOG HAS LIFTED ACROSS THE EASTERN CAROLINAS
BUT STUBBORN LOW CLOUDS IN THE SC PEE DEE REGION MAY TAKE ANOTHER 30
MINUTES OR SO TO BURN OFF. MOSTLY SUNNY SKIES LATE THIS MORNING WILL
TURN PARTLY CLOUDY ACROSS MOST OF OUR AREA THIS AFTERNOON AS FAIRLY
STEEP LOW-LEVEL LAPSE RATES AND GOOD MOISTURE CONTENT BELOW 850 MB
HELP PRODUCE A CUMULUS CLOUD FIELD. THE 12Z CHS SOUNDING SHOWED THE
06Z GFS AND NAM MODELS WERE BOTH 5 DEGREES F TOO DRY WITH DEWPOINTS
FROM THE SURFACE UP THROUGH 850 MB. THIS ADDITIONAL MOISTURE SHOULD
HELP ENHANCE THE AFTERNOON CUMULUS.
THE BIGGEST QUESTION MARK WITH TODAY`S FORECAST IS THE POTENTIAL OF
AFTERNOON AND EVENING SHOWERS. THE 06Z GFS AND NAM MODELS PRODUCE
SOME ISOLATED SHOWERS BUT THE ASSOCIATED STATISTICAL OUTPUT SHOWS
ONLY 0-10 PERCENT POPS. THE PAST SEVERAL HRRR RUNS ALSO SHOW DRY
WEATHER THROUGH THIS EVENING. GIVEN FAIRLY MOIST LOW-LEVELS AND
STEEP LAPSE RATES UP THROUGH AN INVERSION AT 10-11 KFT I EXPECT AT
LEAST SOME ISOLATED SHOWERS MUCH LIKE EXPERIENCED YESTERDAY. THE
SEABREEZE BOUNDARY...PARTICULARLY IN SE NORTH CAROLINA WHERE NATURAL
CONVERGENCE IS PRODUCED BY THE SEABREEZE...IS AN OBVIOUSLY TRIGGER.
A SECOND POSSIBLE TRIGGER IS THE ARRIVAL OF A DYING COLD FRONT FROM
THE NORTH LATE THIS AFTERNOON...ALTHOUGH CONVERGENCE IS WEAKENING
WITH THIS FEATURE GIVEN THE INCREASINGLY SIMILAR WIND DIRECTIONS ON
EITHER SIDE. IN ANY CASE WE`LL KEEP POPS NO HIGHER THAN 25% THROUGH
THIS EVENING.
HIGHS TODAY SHOULD REACH THE MID 80S AWAY FROM THE OCEAN...WITH
HIGHS AROUND 80 ON THE BEACHES. MORNING LOW CLOUDS AND FOG SHOULD
HAVE NO IMPACT ON THESE TEMPERATURES.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SHORT TERM WILL FEATURE A TRANSITIONAL
PERIOD AS SPLIT FLOW 500MB PATTERN TRANSITIONS TO A HIGHLY AMPLIFIED
TROUGH ACROSS THE EASTERN HALF OF THE COUNTRY. HIGH PRESSURE
DRIFTING ACROSS THE MID ATLANTIC SUNDAY WILL ALLOW WINDS TO TURN
GRADUALLY FROM NE TO SE THROUGH THE DAY. THIS OCCURS AT THE SAME
TIME THAT A 60KT 300MB JET MAX MOVES ACROSS NC. EVEN THOUGH FORECAST
SOUNDINGS REMAIN RELATIVELY DRY ABOVE 850MB...THE INCREASING
MOISTURE ON SE FLOW COMBINED WITH THE SUBTLE UPPER SUPPORT COULD
SPAWN AN ISOLATED SHOWER/TSTM DURING THE AFTN...AND WILL KEEP
INHERITED SCHC POP. TEMPS SUNDAY WILL BE RIGHT AROUND CLIMO...LOW TO
MID 80S MOST LOCATIONS. MINS WILL FALL TO RIGHT AROUND CLIMO SUNDAY
NIGHT...MID 60S.
SOUTHERN STREAM VORT MAX WILL GET STRUNG OUT AND LIFT NORTHEAST AS A
DEEP 500MB TROUGH DIGS ACROSS THE CENTRAL PLAINS. WAVE OF LOW
PRESSURE DEVELOPS BENEATH THIS UPPER VORT AND SLIDES NORTHEAST
TOWARDS THE AREA...PUSHING A WARM FRONT ACROSS THE CAROLINAS DURING
MONDAY. AS THIS OCCURS...FLOW WITHIN THE COLUMN TURNS TO BECOME DEEP
SOUTHEASTERLY...ADVECTING SIGNIFICANTLY INCREASED MOISTURE INTO THE
CAROLINAS. ALTHOUGH BEST RAIN CHANCES WILL HOLD OFF UNTIL MONDAY
NIGHT...WILL SHOW INCREASING POP THROUGH THE DAY FROM SOUTH TO
NORTH. WITH PWATS RISING TO NEARLY TWO INCHES MONDAY NIGHT...AND
FORCING INCREASING LATE...EXPECT A PERIOD OF MDT/HEAVY RAINFALL
DEVELOPING AT THE END OF THE PERIOD...AND WILL BUMP ALL LOCATIONS TO
LIKELY POP. TEMPS WILL BE TEMPERED BY CLOUDS/RAIN...REMAINING IN THE
LOW 80S. INCREASED SOUTHERLY FLOW AND RAIN WILL KEEP MINS WELL ABOVE
CLIMO...ONLY FALLING TO AROUND 70.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...A VERY WET TUESDAY EXPECTED BEFORE DRIER AND
COOLER WEATHER DEVELOPS FOR THE LATTER HALF OF THE UPCOMING WEEK.
INGREDIENTS APPEAR TO BE COMING TOGETHER TO SUPPORT A VERY WET
TUESDAY WITH MODERATE/HEAVY RAINFALL LIKELY ACROSS THE ENTIRE CWA.
SOUTHERN STREAM VORT MAX BEGINS TO PHASE WITH NORTHERN STREAM ENERGY
JUST WEST OF THE CWA. AS THIS OCCURS...SURFACE LOW WORKS UP ALONG
THE APPALACHIANS ACROSS THE WESTERN CAROLINAS. THE KEEPS THE CWA IN
DEEP SOUTHERLY FLOW WHICH ADVECTS A STRONG THETA-E RIDGE INTO THE
AREA. PWATS RISE TO NEARLY 2.25 INCHES...OR 2-3 SD`S ABOVE NORMAL
FOR MID-SEPTEMBER. AT THE SAME TIME...WE ENTER THE RIGHT DIFFLUENT
PORTION OF AN 80-90KT 300MB JET AND 850MB TRANSPORT WINDS APPROACH
40-50 KTS. THIS ALL POINTS TOWARDS PERIODS OF HEAVY RAINFALL...AND
HPC IS PAINTING 1-1.5" OF QPF ACROSS THIS AREA. WITH SUCH STRONG LOW
LEVEL WINDS IN PLACE...COULD BE CONCERNED ABOUT A SEVERE WIND
POTENTIAL...HOWEVER...LACK OF INSOLATION KEEPS ML LAPSE RATES BELOW
6C/KM...SO HEAVY RAIN EXPECTED TO BE THE PRIMARY THREAT. RAIN WILL
CONTINUE THROUGH TUESDAY NIGHT BEFORE LOW MOVES OFF TO THE NORTHEAST
AND ITS ASSOCIATED COLD FRONT DRAGS THROUGH BY EARLY WEDNESDAY.
BEHIND THIS FRONT...COOLER AND DRIER WEATHER EXPECTED THROUGH THE
REST OF THE EXTENDED. HIGH PRESSURE BUILDS DOWN THE COAST AS 500MB
TROUGH RELOADS ACROSS THE MIDWEST. THIS WILL BRING COOL E/NE LOW
LEVEL FLOW...BUT ALSO MOSTLY SUNNY AND DRY CONDITIONS TO FINISH THE
WEEK.
TEMPS TUESDAY WILL BE AROUND CLIMO WITH CLOUDS AND RAIN...FALLING TO
BELOW CLIMO FOR THE REST OF THE WEEK BEHIND THE COLD FRONT. MINS
TUESDAY NIGHT WILL BE ABOVE CLIMO...BEFORE FALLING TO NEAR NORMAL
WED-FRI.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...FAIRLY WIDESPREAD FOG/STRATUS OVER THE REGION THAT
SHOULD MIX OUT BY 13Z OR SHORTLY THEREAFTER. WASHED OUT COLD FRONT
DROPPING THROUGH THE REGION WILL NOT PROVIDE MUCH IN THE WAY OF
LIFT. LITTLE TO NO CONVECTION IS EXPECTED...PERHAPS ISOLATED ALONG
THE RESULTANT. REINFORCING HIGH PRESSURE WILL GIVE US LIGHT
NORTHEAST FLOW...BECOMING SOUTHEAST ALONG THE COAST.
TONIGHT...INCREASING MOISTURE AS THE BOUNDARY UNDERGOES
FRONTOGENESIS AND RIDES BACK TO THE NORTH AS A WARM FRONT. WILL LOOK
CLOSER AT THE POTENTIAL FOR FOG SUNDAY MORNING IN THE NEXT SET OF
TAFS.
THE EXTENDED OUTLOOK THROUGH WEDNESDAY...LOW CONFIDENCE IFR IN
PRE-DAWN BR SUN-TUE. ISOLATED SHRA/TSRA SUN BECOMING SCATTERED ON
MON...NUMEROUS TUE. VFR DEVELOPING WED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...A SURFACE COLD FRONT OVER NORTHERN NORTH
CAROLINA WILL MOVE SOUTH TO CAPE FEAR LATE THIS AFTERNOON. WINDS ON
BOTH SIDES OF THE BOUNDARY ARE NORTHERLY SO THE FEATURE IS
CERTAINLY LOSING ITS DEFINITION AS IT MOVES SOUTH. UNLESS THERE IS
A LINE OF CLOUDS OR SHOWERS ACCOMPANYING THE FRONT...THE ONLY IMPACT
MARINERS SHOULD NOTE AS THE FRONT REACHES US IS A VEERING OF THE
WIND DIRECTION A LITTLE MORE EASTERLY. OTHERWISE NORTH-NORTHEASTERLY
WINDS AROUND 10 KT WILL CONTINUE THROUGH THE DAY...TURNING EAST TO
EVEN SOUTHEAST ALONG THE IMMEDIATE COAST AS A WEAK SEABREEZE
DEVELOPS. SEA HEIGHTS AT THE BUOYS ARE 3-4 FT LIKE YESTERDAY...BUT
SPECTRAL WAVE DATA LOOKS VERY DIFFERENT THAN YESTERDAY WITH VERY
LITTLE SHORT PERIOD WAVE ENERGY PRESENT. THE DOMINANT PERIOD IS NOW
9-10 SECONDS IN AN EASTERLY SWELL THAT SHOULD PERSIST THROUGH
TONIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE DRIFTING ACROSS THE
MID-ATLANTIC STATES WILL KEEP WINDS LIGHT SUNDAY...AS THEY VEER
SLOWLY FROM THE NE EARLY...TO SE BY NIGHT. SEAS SUNDAY WILL FALL
SLOWLY THROUGH THE DAY...FROM 3-4 FT EARLY TO 2-4 FT LATE...FORMED
BY A COMBINATION OF AN EASTERLY WIND WAVE AND A 2-3 FT/12SEC SE
SWELL FROM HURRICANE NADINE. CONDITIONS ACROSS THE WATERS WILL
DETERIORATE MONDAY AS A STORM SYSTEM PASSES WEST OF THE AREA. A
WARM FRONT WILL CROSS THE WATERS DURING MONDAY...TURNING WINDS TO
THE SOUTH...WHICH WILL THEN INCREASE DRAMATICALLY MONDAY NIGHT.
WINDS LESS THAN 10 KTS EARLY MONDAY WILL RISE UP TO 15-20 KTS
MONDAY NIGHT. ALTHOUGH THE LONG PERIOD SWELL WILL DECAY AS
HURRICANE NADINE PULLS AWAY...THIS INCREASING WIND WILL FORCE
STEEPER WAVES...AND SEAS WILL BUILD TO 3-5 FT BY THE END OF THE
PERIOD...WITH ISOLATED 6 FTERS POSSIBLE. AT THIS TIME IT APPEARS A
SCEC WILL BE NEEDED MONDAY NIGHT...WITH AN SCA POSSIBLE.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...STRONG SOUTHERLY WINDS TUESDAY CREATE
HAZARDOUS CONDITIONS ACROSS THE COASTAL WATERS...WITH A SMALL CRAFT
ADVISORY LIKELY NEEDED MUCH OF THE DAY. SOUTHERLY WINDS AHEAD OF A
COLD FRONT WILL BE 15-20 KTS...POSSIBLY HIGHER...AND HELP BUILD SEAS
TO 4-6 FT. THESE WAVES WILL BE QUITE STEEP AS WELL...WITH A DOMINANT
PERIOD OF 5-6 SECONDS. VERY LATE TUESDAY NIGHT THE COLD FRONT WILL
CROSS THE WATERS...TURNING WINDS TO THE NW...THEN NE ON WEDNESDAY
WHILE SPEEDS DECREASE TO 10-15 KTS. SEAS FALL QUICKLY...BECOMING 2-3
FT THROUGH MUCH OF WEDNESDAY...ALTHOUGH A CONFUSED SEA STATE IS
LIKELY EARLY WEDNESDAY DUE TO SEVERAL DIFFERENT WAVE GROUPS PRESENT
IN THE SPECTRUM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
932 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SOUTH OF THE REGION TODAY. HIGH
PRESSURE WILL BUILD OVER THE AREA TONIGHT INTO SUNDAY THEN MOVE
OFFSHORE SUNDAY NIGHT. LOW PRESSURE WILL MOVE NORTH FROM THE GULF
COAST REGION MONDAY AND ACROSS WESTERN NORTH CAROLINA MONDAY
NIGHT. A COLD FRONT WILL MOVE ACROSS THE REGION TUESDAY NIGHT
FOLLOWED BY HIGH PRESSURE BUILDING IN FROM THE NORTHWEST LATE
WEDNESDAY INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 930 AM SATURDAY...LATEST RUNS OF BOTH THE RAP AND NAM12 SHOW
NO PRECIPITATION ACROSS THE CWA FOR THE REMAINDER OF THE DAY AND
HAVE UPDATED TO DROP ANY MENTION OF POPS. COLD FRONT IS NOW SOUTH
OF THE CWA WITH DECENT SUBSIDENCE KICKING IN. EXPECT SUNSHINE TO
ALLOW MAX TEMPERATURES TO REACH FORECAST VALUES IN THE LOWER 80S
OVER MOST LOCATIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
AS OF 215 AM SATURDAY...HIGH PRES WILL BUILD IN FROM THE N WITH
DRY WX EXPECTED. AS WINDS GO LIGHT INLAND WILL AGAIN HAVE THE
THREAT FOR SOME PATCHY FOG LATE. LOWS WILL RANGE FROM THE UPR 50S
COOLER INLAND SPOTS TO MID/UPR 60S BEACHES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 315 AM SAT...MODELS ARE ALL IN GENERAL GOOD AGREEMENT
THROUGH THE PERIOD UNTIL MID WEEK WHEN THERE ARE MINOR TIMING
DIFFERENCES WITH THE COLD FRONT PUSHING OFF THE COAST ON WED.
GENERALLY FOLLOWED A BLEND OF MODEL GUIDANCE FOR MAJOR FEATURES.
FOLLOWED CLOSE TO MOS BIAS CORRECTED GUIDANCE FOR TEMPS THROUGH
THE PERIOD...WHICH WILL BE PRETTY CLOSE TO CLIMATOLOGY VALUES. MAD
ONLY MINOT POP ADJUSTMENTS THROUGH THE PERIOD. GENERALLY JUST A
SLIGHT CHANCE OF A SHOWER THROUGH SUNDAY INTO SUNDAY NIGHT...WITH
A GRADUAL INCREASE IN POPS ON MONDAY. THE BEST CHANCE OF SHOWERS
AND THUNDERSTORMS WILL COME ON TUESDAY AHEAD OF THE APPROACHING
COLD FRONT. COULD SEE SOME STRONG THUNDERSTORMS BUT CONFIDENCE IN
TIMING AND INSTABILITY IS TOO LOW AT THIS POINT TO GIVE E
DEFINITIVE CHANCE OF SEVERE STORMS. THE ECMWF DRIES THINGS OUT
DEFINITIVELY ON WEDNESDAY...BUT GFS IS A BIT SLOWER TO CLEAR
THINGS OUT COMPLETELY ALONG THE COAST...THEREFORE CONTINUED TO
CARRY SLIGHT CHANCE POPS THROUGH THE DAY WEDNESDAY BEFORE DRYING
THINGS OUT THURSDAY AND FRIDAY.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 615 AM SATURDAY...WIDESPREAD LIFR IN FOG/ST EARLY THIS
MORN. CONDITIONS SHLD BEGIN TO IMPROVE AROUND 12Z AS WEAK COLD
FRONT DROPS INTO REGION AND MIXING STARTS. ONCE FOG LIFTS EXPECT
VFR REST OF THE DAY WITH POSS SOME ISOLD SHRA NEAR CST LATE. AS
HIGH PRES BUILDS IN FROM THE N TONIGHT WILL AGAIN HAVE THE THREAT
FOR SOME PATCHY FOG AND IFR CONDITIONS AT TIMES MAINLY AFT 08Z.
LONG TERM /SUNDAY THROUGH WED/...
AS OF 315 AM SAT...VFR CONDITIONS PREVAIL THROUGH SUNDAY INTO
SUNDAY NIGHT ALTHOUGH CAN`T RULE OUT A STRAY SHOWER SUNDAY NIGHT.
THE CHANCE FOR SCATTERED SHOWERS WILL INCREASE INTO MONDAY AND
MONDAY NIGHT...BUT WOULD EXPECT MOSTLY MVFR CONDITIONS. BY TUESDAY
MORE WIDESPREAD SHOWERS AND TSTMS WILL MOVE INTO THE AREA AHEAD OF
A COLD FRONT. MVFR CONDITIONS WILL BE PREDOMINATE WITH PERIODS OF
IFR POSSIBLE OCCASIONALLY. CONDITIONS SHOULD BEGIN TO IMPROVE
BEHIND THE FRONT ON WEDNESDAY.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 930 AM SATURDAY...GENERALLY NW/NNW WINDS OF 10 TO 15 KNOTS
ARE EXPECTED THROUGH THIS AFTERNOON WITH SEAS OF 2 TO 4 FEET
BUILDING TO 3 TO 5 FEET LATE. OF INTEREST WILL BE DEVELOPMENT OF
LONG PERIOD SWELLS BY THIS EVENING. CURRENT OBSERVATIONS SHOWING
ABOUT 8 SECOND PERIODS...BUT THESE ARE FORECAST TO INCREASE TO 15
SECONDS OR GREATER BY EVENING. THIS WILL LEAD TO ROUGH SURF AND AN
INCREASED THREAT OF RIP CURRENTS. N TO NE WINDS WILL CONT AT
MAINLY 10 TO 15 KTS TONIGHT AS HIGH PRES BUILDS IN FROM THE
N...COULD BE SOME GUSTS TO 20 KT EARLY ESPCLY CNTRL AND NRN WTRS.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 315 AM SAT...AS MENTIONED IN LONG TERM DISCUSSION NO
SIGNIFICANT MODEL DIFFERENCES THROUGH THE PERIOD. THERE IS JUST A
MINOR TIMING DIFFERENCE WITH THE COLD FRONT MOVING THROUGH THE
REGION WEDNESDAY. FOLLOWED A BLEND OF GFS/ECMWF FOR WINDS IN THAT
TIME PERIOD. EARLY IN THE PERIOD SCA CONDITIONS DUE MAINLY TO THE
LONG PERIOD SWELL WILL BEGIN TO DIMINISH. SEAS WILL FALL BELOW SCA
CONDITIONS ALL WATERS BY LATE SUNDAY AFTERNOON. THE LULL IN CALM
CONDITIONS WILL BE SHORT ON MONDAY AS WINDS BECOME SOUTHERLY INCREASE
TO 20 TO 25 KT AHEAD OF THE APPROACHING COLD FRONT ON
TUESDAY...WITH SEAS BUILDING TO 6 TO 7 FEET ACROSS A LARGE PORTION
OF THE WATERS. THE COLD FRONT SHOULD PASS THROUGH THE WATERS
WEDNESDAY WITH SEAS SUBSIDING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ103.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 PM EDT
SUNDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 1 PM EDT
SUNDAY FOR AMZ150-156-158.
&&
$$
SYNOPSIS...RF
NEAR TERM...CTC
SHORT TERM...RF
LONG TERM...RSB
AVIATION...RSB/RF
MARINE...RSB/CTC/RF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
715 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP SOUTHWARD THROUGH NORTH CAROLINA
TODAY... THEN STALL NEAR THE SOUTH CAROLINA BORDER THROUGH SUNDAY...
BEFORE DRIFTING BACK NORTHWARD AS A WARM FRONT SUNDAY NIGHT. A
STRONG STORM SYSTEM WILL APPROACH THE AREA FROM THE SOUTHWEST MONDAY
THROUGH TUESDAY.
&&
.NEAR TERM /TODAY THROUGH SUNDAY NIGHT/...
AS OF 215 AM SATURDAY...
FOR TODAY/TONIGHT: EXPECT A FAIRLY QUIET AND SUMMER-LIKE DAY
OVERALL... BUT WITH AN INCREASE IN CLOUDS LATE. THE LATEST SURFACE
ANALYSIS SHOWS THE VERY WEAK SURFACE RIDGE CONTINUING TO LOSE ITS
GRIP ON THE AREA AHEAD OF AN INCOMING COOL FRONT... STRETCHING FROM
NEW ENGLAND ACROSS SE WV TO THE MO/AR BORDER. AS ANTICIPATED...
SURFACE DEW POINTS HAVE REBOUNDED FROM 24 HOURS AGO TO AROUND 60
WEST AND MID-UPPER 60S EAST. WITH LIGHT WINDS AND ONLY PATCHES OF
HIGH CLOUDS EARLY THIS MORNING... FOG FORMATION IS FAVORED
ESPECIALLY IN LOW-LYING AREAS AND NEAR BODIES OF WATER OVER THE
EASTERN CWA. INDEED... THE HRRR MODEL DEPICTS DENSE FOG FROM RDU
NORTH AND EAST AS WELL AS IN THE FAR SRN CWA IN THE PREDAWN HOURS.
OTHERWISE... THE DEPARTURE OF THE WEAK UPPER LEVEL WAVE IS NOW
PUSHING YESTERDAY`S COPIOUS MID/HIGH CLOUDINESS OFF THE NC COAST.
ANY DAYBREAK FOG/STRATUS IN THE EASTERN CWA SHOULD LIFT AND MIX OUT
BY MID MORNING... AND FORECAST SOUNDINGS UNIFORMLY SUPPORT
DEVELOPMENT OF SCATTERED FLAT DAYTIME CUMULUS BY THIS AFTERNOON.
WE`LL ALSO SEE THICKENING MID/HIGH CLOUDS BY LATE IN THE DAY AS THE
CLOUD SHIELD FROM THE OH VALLEY BACK OVER THE MID MISS VALLEY SLIDES
EASTWARD. THE SURFACE FRONT IS EXPECTED TO MAKE A SLOW SOUTHWARD
DRIFT THROUGH CENTRAL NC TODAY. A PRECEDING WEAK TROUGH WILL SWING
SURFACE WINDS AROUND TO NORTHERLY AND NORTHEASTERLY THIS MORNING...
BEFORE THE FRONTAL ZONE ITSELF DROPS SOUTHWARD LATER THIS
AFTERNOON... REACHING THE SC BORDER AREA BY EARLY-MID EVENING. THE
DELAY IN THE ARRIVAL OF COOLER LOW LEVEL THICKNESSES (ESPECIALLY IN
SRN NC WHERE THICKNESSES WILL PEAK NEAR 1410 METERS) AND LIMITED
CLOUD COVER THROUGH THE FIRST HALF OF THE DAY WILL ALLOW TEMPS TO
TOP OUT NEAR 80 TO 85... A COUPLE OF DEGREES ABOVE NORMAL. REGARDING
PRECIP CHANCES... DAYTIME HEATING WITH HIGHER SURFACE DEW POINTS AND
WEAK MASS CONVERGENCE ALONG THE PREFRONTAL TROUGH MAY INSTIGATE A
FEW SHALLOW LATE-AFTERNOON SHOWERS IN THE SOUTHEAST CWA... A
SCENARIO SUPPORTED BY THE CONVECTION-ALLOWING WRF-NMM. IN GENERAL
HOWEVER... THE MID LEVELS ARE LIKELY TO REMAIN TOO DRY AND STABLE
FOR ANY CONVECTIVE PRECIP TODAY... AND DYNAMIC FORCING FOR ASCENT IS
ABSENT AS WELL. BUT THE VORTICITY MAXIMUM CURRENTLY NOTED IN WATER
VAPOR IMAGERY OVER TN IS EXPECTED TO EASE EASTWARD THROUGH TODAY...
SHEARING ACROSS THE NC MTNS INTO THE SRN FOOTHILLS AND SRN PIEDMONT
STARTING THIS EVENING. ACCOMPANYING THIS WILL BE AN INCREASE IN
MOIST UPGLIDE AROUND 300K OVER WRN NC... AS THE 850 MB ANTICYCLONE
JUST TO OUR WEST THIS MORNING SHIFTS ESE RESULTING IN RETURN FLOW
INTO THE WRN CAROLINAS. SO ALONG WITH THE THICKER MID/HIGH CLOUDS
SPREADING IN FROM THE WEST THIS EVENING AND TONIGHT... LOWER LEVEL
MOISTURE WILL INCREASE AS WELL ESPECIALLY IN AREAS WEST OF HIGHWAY
1. WILL BRING IN A CHANCE OF SHOWERS AND STORMS INTO THE WRN AND SW
CWA OVERNIGHT. LOWS 57-64 WITH CLOUDS AND THE STALLED FRONT KEEPING
TEMPS UP IN THE SOUTHERN CWA.
FOR SUNDAY/SUNDAY NIGHT: A DEEP POSITIVELY-TILTED MID LEVEL TROUGH
WHICH NOW STRETCHES FROM SRN NM ACROSS THE TX PANHANDLE INTO ERN KS
WILL SHIFT EASTWARD ACROSS TX SUNDAY/SUNDAY NIGHT... WHILE WEAK
VORTICITY SHEARS EASTWARD IN FAST WEST-EAST FLOW AHEAD OF THE TROUGH
INTO NC. AT THE SURFACE... THE FRONTAL ZONE WILL REMAIN STALLED NEAR
THE NC/SC STATE LINE THROUGH SUNDAY... BUT AS THE HIGH PRESSURE AREA
CENTERED TO OUR NORTH OVER SWRN PA PUSHES EASTWARD ACROSS THE MID
ATLANTIC REGION... THE LOW LEVEL FLOW WILL STEADILY VEER FROM
NORTHEASTERLY TO EASTERLY THEN FINALLY TO SOUTHEASTERLY... WITH THE
FRONTAL ZONE KICKING BACK NORTHWARD THROUGH THE SRN PIEDMONT/WRN
SANDHILLS. IN ADDITION TO THE IMPROVING MID LEVEL LIFT OVER NC...
UPPER DIVERGENCE WILL STEADILY INCREASE AS FLOW ALOFT SPEEDS UP TO
OUR NORTH AND NW. AND THE DEEPENING LOW LEVEL RETURN FLOW WILL
GENERATE IMPROVING MOIST UPGLIDE PARTICULARLY OVER WRN AND NRN NC...
ALONG THE NORTHEAST-DRIFTING AND WEAKENING SURFACE FRONTAL ZONE.
MOISTURE WILL CONTINUE TO DEEPEN WITH PRECIP WATER VALUES INCREASING
TO 150-200% OF NORMAL SUNDAY THROUGH SUNDAY NIGHT. EXPECT THE CHANCE
FOR SHOWERS AND A FEW STORMS TO INCREASE AND SPREAD FROM THE FAR WRN
CWA EARLY ACROSS THE REST OF THE WRN CWA THROUGH SUNDAY... THEN WE
SHOULD SEE SCATTERED SHOWERS AND STORMS AREAWIDE (YET STILL FOCUSED
ON THE WEST/NORTH WHERE MOISTURE TRANSPORT WILL BE HIGHEST) SUNDAY
EVENING AND NIGHT AS THE MOIST UPGLIDE AND UPPER LEVEL FORCING
COMPENSATES FOR THE LOSS OF DAYTIME HEATING AND INSTABILITY.
THICKNESSES STAY NEAR SEASONAL NORMALS BUT WITH CLOUDS OVERSPREADING
THE AREA... EXPECT HIGHS TO BE A BIT UNDER NORMAL... IN THE UPPER
70S TO LOWER 80S. LOWS 61-65. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 240 AM SATURDAY...
MONDAY...
AN UPPER LOW CURRENTLY OVER SOUTHERN NEW MEXICO WILL OPEN UP AND
DRIFT SLOWLY ACROSS THE SOUTHERN US THIS WEEKEND...AND EVENTUALLY
LIFT NORTHEAST TOWARD THE APPALACHIANS LATE MONDAY WHILE A NORTHERN
STREAM SHORTWAVE AMPLIFIES OUT OF CANADA INTO THE MID WEST.
WARM...MOIST ADVECTION WILL RAMP UP MONDAY AS A DEEP SOUTHWESTERLY
FLOW DEVELOPS AHEAD OF THE SOUTHERN STREAM WAVE...TAPPING THE GULF
OF MEXICO WHERE PW VALUES ARE WELL OVER 2 INCHES. HOWEVER...THE
STRENGTHENING LOW LEVEL JET AND BEST UPPER DIVERGENCE ASSOCIATED
WITH AN INTENSIFYING UPPER JET OVER THE GREAT LAKES WILL STILL BE
WEST OF THE MOUNTAINS DURING THE DAY...AND ONLY ISOLATED TO
SCATTERED WARM ADVECTION SHOWERS/STORMS ARE EXPECTED OVER CENTRAL
NC. DEEP LAYER SHEAR WILL BE INCREASING DURING THE DAY AS THE
HEIGHTS ALOFT BEGIN TO FALL OVER THE OHIO VALLEY AHEAD OF THE
NORTHERN STREAM WAVE. HOWEVER... INSTABILITY MAY BE HAMPERED BY
WIDESPREAD CLOUD COVER AND RELATIVELY WARM...MOIST MID LEVELS. WHILE
A FEW STRONG STORMS WILL BE POSSIBLE... THE MAIN SEVERE THREAT
SHOULD INSTEAD COME LATER MONDAY NIGHT INTO TUESDAY AS BETTER
SYNOPTIC FORCING ARRIVES. HIGHS MONDAY ARE FORECAST TO RANGE FROM
THE MID 70S NORTHWEST TO LOWER 80S SOUTHEAST.
MONDAY NIGHT THROUGH TUESDAY NIGHT...
THE AFOREMENTIONED SOUTHERN STREAM WAVE IS FORECAST TO WEAKEN AND
LIFT NORTHEAST FROM THE GULF COAST AND ALONG THE APPALACHIANS MONDAY
NIGHT AND TUESDAY. STRENGTHENING UPPER LEVEL DIVERGENCE...ALONG
WITH A 35-45 KT LOW LEVEL JET AND STRONG LOW LEVEL VEERING WILL
BRING A A PERIOD OF WIDESPREAD SHOWERS/STORMS TO THE AREA DURING
THIS PERIOD. HOWEVER...MODELS HAVE DIVERGED A BIT IN THE LAST FEW
RUNS REGARDING THE TIMING OF BEST FORCING...WITH THE GFS NOW
SLIGHTLY FASTER THAN THE ECMWF/NAM. PRECIP WILL CONTINUE TO BE
FOCUSED ALONG THE MOUNTAINS AND FOOTHILLS MONDAY EVENING AND
INITIALLY THERE MAY BE A STRONG GRADIENT BETWEEN WIDESPREAD SHOWERS
OVER THE WESTERN PIEDMONT AND LITTLE TO NO ACTIVITY TO THE EAST.
HOWEVER...AS THE REMNANTS OF THE SOUTHERN STREAM SHORTWAVE
ARRIVES...PRECIP WILL SPREAD EAST ACROSS THE CWA...BETWEEN 06Z AND
18Z TUESDAY BASED ON CURRENT MODEL PROJECTIONS. WHILE MODELS HAVE
GRADUALLY BACKED OFF ON SHOWING A SURFACE LOW EAST OF THE
MOUNTAINS...THERE WILL STILL BE A WINDOW WHERE BACKED SURFACE
WINDS...STRONG LOW LEVEL SHEAR AND LOW LCLS MAY SUPPORT A TORNADO
THREAT. HOWEVER...INSTABILITY AND POTENTIAL UPDRAFT STRENGTH ARE
QUESTIONABLE DUE TO THE LESS FAVORABLE OVERNIGHT
TIMING...PARTICULARLY IN THE GFS SOLUTION. AS SUCH... QUITE A BIT OF
UNCERTAINTY REMAINS REGARDING THE SEVERE/TORNADO THREAT. HEAVY RAIN
LOOKS TO ALMOST CERTAINLY BE AN ISSUE...ESPECIALLY OVER THE WESTERN
PIEDMONT...WITH A PROLONGED FETCH OF GULF MOISTURE AND PERSISTENT
ISENTROPIC/UPSLOPE AIDED ACCENT MONDAY NIGHT. LOWS SHOULD BE MUGGY
IN THE MID TO UPPER 60S.
AS THE COLD FRONT APPROACHES FROM THE MID WEST ON TUESDAY...MODELS
ARE SHOWING A BIT MORE OF A NEGATIVE TILT TO THE MAIN TROUGH AXIS AS
IT SWINGS ACROSS THE OH/TN VALLEY REGIONS. THUS...SHOWERS AND
STORMS SHOULD BEGIN TO SHIFT EAST ACROSS THE CWA MORE RAPIDLY BY
TUESDAY AFTERNOON AND EVENING...MOVING EAST OF THE COASTAL PLAIN BY
TUESDAY NIGHT. THE COLD FRONT MAY LAG A BIT...BUT SHOULD ALSO CLEAR
THE AREA BY WEDNESDAY MORNING...WITH HIGH PRESSURE BUILDING ACROSS
THE CENTRAL APPALACHIANS. QUIET WEATHER IS THEN EXPECTED THROUGH
THE END OF THE WEEK...WITH THE POTENTIAL FOR ANOTHER NORTHERN STREAM
WAVE APPROACHING FROM THE MIDWEST NEXT WEEKEND.
REGARDING POPS AND TEMPS....
WILL NOT MAKE ANY SIGNIFICANT CHANGES TO THE LIKELY/CATEGORICAL POPS
MONDAY NIGHT AND TUESDAY...AND WILL HAVE POPS COMING TO AN END IN
THE EAST PRIOR TO 12Z WEDNESDAY. HIGHS TUESDAY WILL BE TRICKY DUE
TO THE PRECIP COVERAGE BUT SHOULD BE MOSTLY IN THE 70S...EXCEPT FOR
THE FAR SOUTHEAST WHERE 80 MAY BE POSSIBLE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 240 AM SATURDAY...
DRIER AND MORE STABLE AIR IS FORECAST TO FILTER ACROSS THE AREA
WEDNESDAY AND THURSDAY AS THE EARLY WEEK STORM SYSTEM DEPARTS THE
REGION AND HIGH PRESSURE BUILDS ACROSS THE LOWER MIDWEST. THIS WILL
LEAD TO A RELATIVE MIN IN HIGH TEMPS...AS MUCH AS 4-8 DEGREES BELOW
NORMAL BASED ON POST-FRONTAL THICKNESSES SOME 15-20M BELOW NORMAL.
MODELS THEN SHOW ANOTHER NORTHERN STREAM WAVE DIVING OUT OF CANADA
AND STRENGTHENING THE LONG WAVE TROUGH OVER THE EASTERN HALF OF THE
US....WITH ANOTHER COLD FRONT POSSIBLY APPROACHING THE CAROLINAS BY
NEXT WEEKEND.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 715 AM SATURDAY...
THE MAIN AVIATION CONCERN THIS MORNING IS AREAS OF FOG. SCT BANKS OF
IFR/LIFR FOG WILL PERSIST NEAR KRWI/KFAY THROUGH 13Z-14Z WITH
ISOLATED BANKS NEAR KRDU. LOWER NEAR-GROUND HUMIDITY AT KINT/KGSO
WILL LIMIT ANY FOG DEVELOPMENT AT THESE SITES.
ANY ADVERSE AVIATION CONDITIONS AT KRDU/KFAY WILL LIFT/MIX OUT BY
14Z. SIMILARLY... THE IFR/LIFR VSBY/CIG AT KRWI WILL SLOWLY IMPROVE
TO VFR THROUGH 15Z. AFTER THIS TIME... DAYTIME CUMULUS CLOUDS THIS
AFTERNOON AT ALL CENTRAL NC FORECAST SITES WILL BE BASED ABOVE 4
THOUSAND FT AGL. A WEAK FRONT WILL SINK SOUTHWARD THROUGH NC DURING
TODAY. WINDS OVER CENTRAL NC WILL BE LIGHT (UNDER 8 KTS OVERALL)
FROM THE NORTH THEN NORTHEAST THIS MORNING... EVENTUALLY SHIFTING TO
BE FROM THE EAST THEN ESE LATER TODAY AS HIGH PRESSURE TO OUR NORTH
BUILDS IN BRIEFLY BEHIND THE FRONT. ONLY ISOLATED SHOWERS ARE
EXPECTED THROUGH NIGHTFALL... HOWEVER CLOUDS BASED ABOVE 4 THOUSAND
FEET WILL STEADILY INCREASE IN NUMBER AND THICKEN BY EARLY
EVENING... RESULTING IN BROKEN TO OVERCAST VFR SKIES AT
KINT/KGSO/KRDU TOWARD 06Z WHILE SKIES REMAIN FAIR AT KRWI/KFAY. NO
SIGNIFICANT FOG IS EXPECTED THROUGH 12Z SUNDAY MORNING.
LOOKING BEYOND 12Z SUNDAY MORNING... CIGS WILL LOWER TOWARD SUNDAY
MORNING BUT WILL MOSTLY REMAIN VFR... AS WILL VSBYS WITH LITTLE TO
NO FOG EXPECTED TO DEVELOP. A MID-UPPER TROUGH OVER NM/TX THIS
MORNING WILL MOVE SLOWLY EASTWARD SUNDAY THROUGH MONDAY AS A
STRENGTHENING FRONT APPROACHES FROM THE WEST... AND AVIATION
CONDITIONS WILL SLOWLY DETERIORATE IN THIS TIME FRAME... STARTING
FIRST AT KINT/KGSO SUNDAY NIGHT WITH MVFR CIGS/VSBYS IN
SHOWERS/STORMS. MVFR TO IFR CONDITIONS ARE LIKELY ALL ACROSS CENTRAL
NC LATE MONDAY WELL INTO TUESDAY WITH STRONG VEERING WINDS THROUGH
THE LOWEST 10 THOUSAND FT. IMPROVING CONDITIONS ARE EXPECTED
WEDNESDAY WITH A COOLER INCOMING AIR MASS BEHIND THE FRONT. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP SOUTHWARD THROUGH NORTH CAROLINA
TODAY... THEN STALL NEAR THE SOUTH CAROLINA BORDER THROUGH SUNDAY...
BEFORE DRIFTING BACK NORTHWARD AS A WARM FRONT SUNDAY NIGHT. A
STRONG STORM SYSTEM WILL APPROACH THE AREA FROM THE SOUTHWEST MONDAY
THROUGH TUESDAY.
&&
.NEAR TERM /TODAY THROUGH SUNDAY NIGHT/...
AS OF 215 AM SATURDAY...
FOR TODAY/TONIGHT: EXPECT A FAIRLY QUIET AND SUMMER-LIKE DAY
OVERALL... BUT WITH AN INCREASE IN CLOUDS LATE. THE LATEST SURFACE
ANALYSIS SHOWS THE VERY WEAK SURFACE RIDGE CONTINUING TO LOSE ITS
GRIP ON THE AREA AHEAD OF AN INCOMING COOL FRONT... STRETCHING FROM
NEW ENGLAND ACROSS SE WV TO THE MO/AR BORDER. AS ANTICIPATED...
SURFACE DEW POINTS HAVE REBOUNDED FROM 24 HOURS AGO TO AROUND 60
WEST AND MID-UPPER 60S EAST. WITH LIGHT WINDS AND ONLY PATCHES OF
HIGH CLOUDS EARLY THIS MORNING... FOG FORMATION IS FAVORED
ESPECIALLY IN LOW-LYING AREAS AND NEAR BODIES OF WATER OVER THE
EASTERN CWA. INDEED... THE HRRR MODEL DEPICTS DENSE FOG FROM RDU
NORTH AND EAST AS WELL AS IN THE FAR SRN CWA IN THE PREDAWN HOURS.
OTHERWISE... THE DEPARTURE OF THE WEAK UPPER LEVEL WAVE IS NOW
PUSHING YESTERDAY`S COPIOUS MID/HIGH CLOUDINESS OFF THE NC COAST.
ANY DAYBREAK FOG/STRATUS IN THE EASTERN CWA SHOULD LIFT AND MIX OUT
BY MID MORNING... AND FORECAST SOUNDINGS UNIFORMLY SUPPORT
DEVELOPMENT OF SCATTERED FLAT DAYTIME CUMULUS BY THIS AFTERNOON.
WE`LL ALSO SEE THICKENING MID/HIGH CLOUDS BY LATE IN THE DAY AS THE
CLOUD SHIELD FROM THE OH VALLEY BACK OVER THE MID MISS VALLEY SLIDES
EASTWARD. THE SURFACE FRONT IS EXPECTED TO MAKE A SLOW SOUTHWARD
DRIFT THROUGH CENTRAL NC TODAY. A PRECEDING WEAK TROUGH WILL SWING
SURFACE WINDS AROUND TO NORTHERLY AND NORTHEASTERLY THIS MORNING...
BEFORE THE FRONTAL ZONE ITSELF DROPS SOUTHWARD LATER THIS
AFTERNOON... REACHING THE SC BORDER AREA BY EARLY-MID EVENING. THE
DELAY IN THE ARRIVAL OF COOLER LOW LEVEL THICKNESSES (ESPECIALLY IN
SRN NC WHERE THICKNESSES WILL PEAK NEAR 1410 METERS) AND LIMITED
CLOUD COVER THROUGH THE FIRST HALF OF THE DAY WILL ALLOW TEMPS TO
TOP OUT NEAR 80 TO 85... A COUPLE OF DEGREES ABOVE NORMAL. REGARDING
PRECIP CHANCES... DAYTIME HEATING WITH HIGHER SURFACE DEW POINTS AND
WEAK MASS CONVERGENCE ALONG THE PREFRONTAL TROUGH MAY INSTIGATE A
FEW SHALLOW LATE-AFTERNOON SHOWERS IN THE SOUTHEAST CWA... A
SCENARIO SUPPORTED BY THE CONVECTION-ALLOWING WRF-NMM. IN GENERAL
HOWEVER... THE MID LEVELS ARE LIKELY TO REMAIN TOO DRY AND STABLE
FOR ANY CONVECTIVE PRECIP TODAY... AND DYNAMIC FORCING FOR ASCENT IS
ABSENT AS WELL. BUT THE VORTICITY MAXIMUM CURRENTLY NOTED IN WATER
VAPOR IMAGERY OVER TN IS EXPECTED TO EASE EASTWARD THROUGH TODAY...
SHEARING ACROSS THE NC MTNS INTO THE SRN FOOTHILLS AND SRN PIEDMONT
STARTING THIS EVENING. ACCOMPANYING THIS WILL BE AN INCREASE IN
MOIST UPGLIDE AROUND 300K OVER WRN NC... AS THE 850 MB ANTICYCLONE
JUST TO OUR WEST THIS MORNING SHIFTS ESE RESULTING IN RETURN FLOW
INTO THE WRN CAROLINAS. SO ALONG WITH THE THICKER MID/HIGH CLOUDS
SPREADING IN FROM THE WEST THIS EVENING AND TONIGHT... LOWER LEVEL
MOISTURE WILL INCREASE AS WELL ESPECIALLY IN AREAS WEST OF HIGHWAY
1. WILL BRING IN A CHANCE OF SHOWERS AND STORMS INTO THE WRN AND SW
CWA OVERNIGHT. LOWS 57-64 WITH CLOUDS AND THE STALLED FRONT KEEPING
TEMPS UP IN THE SOUTHERN CWA.
FOR SUNDAY/SUNDAY NIGHT: A DEEP POSITIVELY-TILTED MID LEVEL TROUGH
WHICH NOW STRETCHES FROM SRN NM ACROSS THE TX PANHANDLE INTO ERN KS
WILL SHIFT EASTWARD ACROSS TX SUNDAY/SUNDAY NIGHT... WHILE WEAK
VORTICITY SHEARS EASTWARD IN FAST WEST-EAST FLOW AHEAD OF THE TROUGH
INTO NC. AT THE SURFACE... THE FRONTAL ZONE WILL REMAIN STALLED NEAR
THE NC/SC STATE LINE THROUGH SUNDAY... BUT AS THE HIGH PRESSURE AREA
CENTERED TO OUR NORTH OVER SWRN PA PUSHES EASTWARD ACROSS THE MID
ATLANTIC REGION... THE LOW LEVEL FLOW WILL STEADILY VEER FROM
NORTHEASTERLY TO EASTERLY THEN FINALLY TO SOUTHEASTERLY... WITH THE
FRONTAL ZONE KICKING BACK NORTHWARD THROUGH THE SRN PIEDMONT/WRN
SANDHILLS. IN ADDITION TO THE IMPROVING MID LEVEL LIFT OVER NC...
UPPER DIVERGENCE WILL STEADILY INCREASE AS FLOW ALOFT SPEEDS UP TO
OUR NORTH AND NW. AND THE DEEPENING LOW LEVEL RETURN FLOW WILL
GENERATE IMPROVING MOIST UPGLIDE PARTICULARLY OVER WRN AND NRN NC...
ALONG THE NORTHEAST-DRIFTING AND WEAKENING SURFACE FRONTAL ZONE.
MOISTURE WILL CONTINUE TO DEEPEN WITH PRECIP WATER VALUES INCREASING
TO 150-200% OF NORMAL SUNDAY THROUGH SUNDAY NIGHT. EXPECT THE CHANCE
FOR SHOWERS AND A FEW STORMS TO INCREASE AND SPREAD FROM THE FAR WRN
CWA EARLY ACROSS THE REST OF THE WRN CWA THROUGH SUNDAY... THEN WE
SHOULD SEE SCATTERED SHOWERS AND STORMS AREAWIDE (YET STILL FOCUSED
ON THE WEST/NORTH WHERE MOISTURE TRANSPORT WILL BE HIGHEST) SUNDAY
EVENING AND NIGHT AS THE MOIST UPGLIDE AND UPPER LEVEL FORCING
COMPENSATES FOR THE LOSS OF DAYTIME HEATING AND INSTABILITY.
THICKNESSES STAY NEAR SEASONAL NORMALS BUT WITH CLOUDS OVERSPREADING
THE AREA... EXPECT HIGHS TO BE A BIT UNDER NORMAL... IN THE UPPER
70S TO LOWER 80S. LOWS 61-65. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 240 AM SATURDAY...
MONDAY...
AN UPPER LOW CURRENTLY OVER SOUTHERN NEW MEXICO WILL OPEN UP AND
DRIFT SLOWLY ACROSS THE SOUTHERN US THIS WEEKEND...AND EVENTUALLY
LIFT NORTHEAST TOWARD THE APPALACHIANS LATE MONDAY WHILE A NORTHERN
STREAM SHORTWAVE AMPLIFIES OUT OF CANADA INTO THE MID WEST.
WARM...MOIST ADVECTION WILL RAMP UP MONDAY AS A DEEP SOUTHWESTERLY
FLOW DEVELOPS AHEAD OF THE SOUTHERN STREAM WAVE...TAPPING THE GULF
OF MEXICO WHERE PW VALUES ARE WELL OVER 2 INCHES. HOWEVER...THE
STRENGTHENING LOW LEVEL JET AND BEST UPPER DIVERGENCE ASSOCIATED
WITH AN INTENSIFYING UPPER JET OVER THE GREAT LAKES WILL STILL BE
WEST OF THE MOUNTAINS DURING THE DAY...AND ONLY ISOLATED TO
SCATTERED WARM ADVECTION SHOWERS/STORMS ARE EXPECTED OVER CENTRAL
NC. DEEP LAYER SHEAR WILL BE INCREASING DURING THE DAY AS THE
HEIGHTS ALOFT BEGIN TO FALL OVER THE OHIO VALLEY AHEAD OF THE
NORTHERN STREAM WAVE. HOWEVER... INSTABILITY MAY BE HAMPERED BY
WIDESPREAD CLOUD COVER AND RELATIVELY WARM...MOIST MID LEVELS. WHILE
A FEW STRONG STORMS WILL BE POSSIBLE... THE MAIN SEVERE THREAT
SHOULD INSTEAD COME LATER MONDAY NIGHT INTO TUESDAY AS BETTER
SYNOPTIC FORCING ARRIVES. HIGHS MONDAY ARE FORECAST TO RANGE FROM
THE MID 70S NORTHWEST TO LOWER 80S SOUTHEAST.
MONDAY NIGHT THROUGH TUESDAY NIGHT...
THE AFOREMENTIONED SOUTHERN STREAM WAVE IS FORECAST TO WEAKEN AND
LIFT NORTHEAST FROM THE GULF COAST AND ALONG THE APPALACHIANS MONDAY
NIGHT AND TUESDAY. STRENGTHENING UPPER LEVEL DIVERGENCE...ALONG
WITH A 35-45 KT LOW LEVEL JET AND STRONG LOW LEVEL VEERING WILL
BRING A A PERIOD OF WIDESPREAD SHOWERS/STORMS TO THE AREA DURING
THIS PERIOD. HOWEVER...MODELS HAVE DIVERGED A BIT IN THE LAST FEW
RUNS REGARDING THE TIMING OF BEST FORCING...WITH THE GFS NOW
SLIGHTLY FASTER THAN THE ECMWF/NAM. PRECIP WILL CONTINUE TO BE
FOCUSED ALONG THE MOUNTAINS AND FOOTHILLS MONDAY EVENING AND
INITIALLY THERE MAY BE A STRONG GRADIENT BETWEEN WIDESPREAD SHOWERS
OVER THE WESTERN PIEDMONT AND LITTLE TO NO ACTIVITY TO THE EAST.
HOWEVER...AS THE REMNANTS OF THE SOUTHERN STREAM SHORTWAVE
ARRIVES...PRECIP WILL SPREAD EAST ACROSS THE CWA...BETWEEN 06Z AND
18Z TUESDAY BASED ON CURRENT MODEL PROJECTIONS. WHILE MODELS HAVE
GRADUALLY BACKED OFF ON SHOWING A SURFACE LOW EAST OF THE
MOUNTAINS...THERE WILL STILL BE A WINDOW WHERE BACKED SURFACE
WINDS...STRONG LOW LEVEL SHEAR AND LOW LCLS MAY SUPPORT A TORNADO
THREAT. HOWEVER...INSTABILITY AND POTENTIAL UPDRAFT STRENGTH ARE
QUESTIONABLE DUE TO THE LESS FAVORABLE OVERNIGHT
TIMING...PARTICULARLY IN THE GFS SOLUTION. AS SUCH... QUITE A BIT OF
UNCERTAINTY REMAINS REGARDING THE SEVERE/TORNADO THREAT. HEAVY RAIN
LOOKS TO ALMOST CERTAINLY BE AN ISSUE...ESPECIALLY OVER THE WESTERN
PIEDMONT...WITH A PROLONGED FETCH OF GULF MOISTURE AND PERSISTENT
ISENTROPIC/UPSLOPE AIDED ACCENT MONDAY NIGHT. LOWS SHOULD BE MUGGY
IN THE MID TO UPPER 60S.
AS THE COLD FRONT APPROACHES FROM THE MID WEST ON TUESDAY...MODELS
ARE SHOWING A BIT MORE OF A NEGATIVE TILT TO THE MAIN TROUGH AXIS AS
IT SWINGS ACROSS THE OH/TN VALLEY REGIONS. THUS...SHOWERS AND
STORMS SHOULD BEGIN TO SHIFT EAST ACROSS THE CWA MORE RAPIDLY BY
TUESDAY AFTERNOON AND EVENING...MOVING EAST OF THE COASTAL PLAIN BY
TUESDAY NIGHT. THE COLD FRONT MAY LAG A BIT...BUT SHOULD ALSO CLEAR
THE AREA BY WEDNESDAY MORNING...WITH HIGH PRESSURE BUILDING ACROSS
THE CENTRAL APPALACHIANS. QUIET WEATHER IS THEN EXPECTED THROUGH
THE END OF THE WEEK...WITH THE POTENTIAL FOR ANOTHER NORTHERN STREAM
WAVE APPROACHING FROM THE MIDWEST NEXT WEEKEND.
REGARDING POPS AND TEMPS....
WILL NOT MAKE ANY SIGNIFICANT CHANGES TO THE LIKELY/CATEGORICAL POPS
MONDAY NIGHT AND TUESDAY...AND WILL HAVE POPS COMING TO AN END IN
THE EAST PRIOR TO 12Z WEDNESDAY. HIGHS TUESDAY WILL BE TRICKY DUE
TO THE PRECIP COVERAGE BUT SHOULD BE MOSTLY IN THE 70S...EXCEPT FOR
THE FAR SOUTHEAST WHERE 80 MAY BE POSSIBLE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 240 AM SATURDAY...
DRIER AND MORE STABLE AIR IS FORECAST TO FILTER ACROSS THE AREA
WEDNESDAY AND THURSDAY AS THE EARLY WEEK STORM SYSTEM DEPARTS THE
REGION AND HIGH PRESSURE BUILDS ACROSS THE LOWER MIDWEST. THIS WILL
LEAD TO A RELATIVE MIN IN HIGH TEMPS...AS MUCH AS 4-8 DEGREES BELOW
NORMAL BASED ON POST-FRONTAL THICKNESSES SOME 15-20M BELOW NORMAL.
MODELS THEN SHOW ANOTHER NORTHERN STREAM WAVE DIVING OUT OF CANADA
AND STRENGTHENING THE LONG WAVE TROUGH OVER THE EASTERN HALF OF THE
US....WITH ANOTHER COLD FRONT POSSIBLY APPROACHING THE CAROLINAS BY
NEXT WEEKEND.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 215 AM SATURDAY...
THE MAIN CONCERN EARLY THIS MORNING IS AREAS OF FOG FORMING NEAR
KRWI. EXPECT IFR/LIFR CONDITIONS TO HOLD HERE FOR THE REMAINDER OF
THE NIGHT... GIVEN THE LIGHT WINDS AND CLEAR SKIES ALOFT ENSURING
GOOD RADIATIONAL COOLING AND LITTLE TO NO LOW LEVEL MIXING
VERTICALLY OR HORIZONTALLY. BANKS OF FOG... MAINLY NEAR BODIES OF
WATER... ARE POSSIBLE AT KRDU AND KFAY AS WELL PRIOR TO 12Z THIS
MORNING. A BRIEF PERIOD OF MVFR VSBY IS POSSIBLE AT THESE LOCATIONS.
LOWER NEAR-GROUND HUMIDITY AT KINT/KGSO WILL LIMIT ANY FOG
DEVELOPMENT AT THESE SITES.
ANY ADVERSE AVIATION CONDITIONS AT KRDU/KFAY WILL LIFT/MIX OUT BY
14Z. SIMILARLY... THE IFR/LIFR VSBY/CIG AT KRWI WILL SLOWLY IMPROVE
TO VFR THROUGH 15Z. AFTER THIS TIME... DAYTIME CUMULUS CLOUDS THIS
AFTERNOON AT ALL CENTRAL NC FORECAST SITES WILL BE BASED ABOVE 4
THOUSAND FT AGL. A WEAK FRONT WILL SINK SOUTHWARD THROUGH NC DURING
TODAY. WINDS OVER CENTRAL NC WILL BE LIGHT (UNDER 8 KTS OVERALL)
FROM THE NORTH THEN NORTHEAST THIS MORNING... EVENTUALLY SHIFTING TO
BE FROM THE EAST THEN ESE LATER TODAY AS HIGH PRESSURE TO OUR NORTH
BUILDS IN BRIEFLY BEHIND THE FRONT. ONLY ISOLATED SHOWERS ARE
EXPECTED THROUGH NIGHTFALL... HOWEVER CLOUDS BASED ABOVE 4 THOUSAND
FEET WILL STEADILY INCREASE IN NUMBER AND THICKEN BY EARLY
EVENING... RESULTING IN BROKEN TO OVERCAST VFR SKIES AT
KINT/KGSO/KRDU TOWARD 06Z WHILE SKIES REMAIN FAIR AT KRWI/KFAY. NO
FOG IS EXPECTED PRIOR TO 06Z TONIGHT.
LOOKING BEYOND 06Z TONIGHT... CIGS WILL LOWER TOWARD SUNDAY MORNING
BUT WILL MOSTLY REMAIN VFR... AS WILL VSBYS WITH LITTLE TO NO FOG
EXPECTED TO DEVELOP. A MID-UPPER TROUGH OVER NM/TX THIS MORNING WILL
MOVE SLOWLY EASTWARD SUNDAY THROUGH MONDAY AS A STRENGTHENING FRONT
APPROACHES FROM THE WEST... AND AVIATION CONDITIONS WILL SLOWLY
DETERIORATE IN THIS TIME FRAME... STARTING FIRST AT KINT/KGSO SUNDAY
NIGHT WITH MVFR CIGS/VSBYS IN SHOWERS/STORMS. MVFR TO IFR CONDITIONS
ARE LIKELY ALL ACROSS CENTRAL NC LATE MONDAY WELL INTO TUESDAY WITH
STRONG VEERING WINDS THROUGH THE LOWEST 10 THOUSAND FT. IMPROVING
CONDITIONS ARE EXPECTED WEDNESDAY WITH A COOLER INCOMING AIR MASS
BEHIND THE FRONT. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
215 AM EDT SAT SEP 15 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP SOUTHWARD THROUGH NORTH CAROLINA
TODAY... THEN STALL NEAR THE SOUTH CAROLINA BORDER THROUGH SUNDAY...
BEFORE DRIFTING BACK NORTHWARD AS A WARM FRONT SUNDAY NIGHT. A
STRONG STORM SYSTEM WILL APPROACH THE AREA FROM THE SOUTHWEST MONDAY
THROUGH TUESDAY.
&&
.NEAR TERM /TODAY THROUGH SUNDAY NIGHT/...
AS OF 215 AM SATURDAY...
FOR TODAY/TONIGHT: EXPECT A FAIRLY QUIET AND SUMMER-LIKE DAY
OVERALL... BUT WITH AN INCREASE IN CLOUDS LATE. THE LATEST SURFACE
ANALYSIS SHOWS THE VERY WEAK SURFACE RIDGE CONTINUING TO LOSE ITS
GRIP ON THE AREA AHEAD OF AN INCOMING COOL FRONT... STRETCHING FROM
NEW ENGLAND ACROSS SE WV TO THE MO/AR BORDER. AS ANTICIPATED...
SURFACE DEW POINTS HAVE REBOUNDED FROM 24 HOURS AGO TO AROUND 60
WEST AND MID-UPPER 60S EAST. WITH LIGHT WINDS AND ONLY PATCHES OF
HIGH CLOUDS EARLY THIS MORNING... FOG FORMATION IS FAVORED
ESPECIALLY IN LOW-LYING AREAS AND NEAR BODIES OF WATER OVER THE
EASTERN CWA. INDEED... THE HRRR MODEL DEPICTS DENSE FOG FROM RDU
NORTH AND EAST AS WELL AS IN THE FAR SRN CWA IN THE PREDAWN HOURS.
OTHERWISE... THE DEPARTURE OF THE WEAK UPPER LEVEL WAVE IS NOW
PUSHING YESTERDAY`S COPIOUS MID/HIGH CLOUDINESS OFF THE NC COAST.
ANY DAYBREAK FOG/STRATUS IN THE EASTERN CWA SHOULD LIFT AND MIX OUT
BY MID MORNING... AND FORECAST SOUNDINGS UNIFORMLY SUPPORT
DEVELOPMENT OF SCATTERED FLAT DAYTIME CUMULUS BY THIS AFTERNOON.
WE`LL ALSO SEE THICKENING MID/HIGH CLOUDS BY LATE IN THE DAY AS THE
CLOUD SHIELD FROM THE OH VALLEY BACK OVER THE MID MISS VALLEY SLIDES
EASTWARD. THE SURFACE FRONT IS EXPECTED TO MAKE A SLOW SOUTHWARD
DRIFT THROUGH CENTRAL NC TODAY. A PRECEDING WEAK TROUGH WILL SWING
SURFACE WINDS AROUND TO NORTHERLY AND NORTHEASTERLY THIS MORNING...
BEFORE THE FRONTAL ZONE ITSELF DROPS SOUTHWARD LATER THIS
AFTERNOON... REACHING THE SC BORDER AREA BY EARLY-MID EVENING. THE
DELAY IN THE ARRIVAL OF COOLER LOW LEVEL THICKNESSES (ESPECIALLY IN
SRN NC WHERE THICKNESSES WILL PEAK NEAR 1410 METERS) AND LIMITED
CLOUD COVER THROUGH THE FIRST HALF OF THE DAY WILL ALLOW TEMPS TO
TOP OUT NEAR 80 TO 85... A COUPLE OF DEGREES ABOVE NORMAL. REGARDING
PRECIP CHANCES... DAYTIME HEATING WITH HIGHER SURFACE DEW POINTS AND
WEAK MASS CONVERGENCE ALONG THE PREFRONTAL TROUGH MAY INSTIGATE A
FEW SHALLOW LATE-AFTERNOON SHOWERS IN THE SOUTHEAST CWA... A
SCENARIO SUPPORTED BY THE CONVECTION-ALLOWING WRF-NMM. IN GENERAL
HOWEVER... THE MID LEVELS ARE LIKELY TO REMAIN TOO DRY AND STABLE
FOR ANY CONVECTIVE PRECIP TODAY... AND DYNAMIC FORCING FOR ASCENT IS
ABSENT AS WELL. BUT THE VORTICITY MAXIMUM CURRENTLY NOTED IN WATER
VAPOR IMAGERY OVER TN IS EXPECTED TO EASE EASTWARD THROUGH TODAY...
SHEARING ACROSS THE NC MTNS INTO THE SRN FOOTHILLS AND SRN PIEDMONT
STARTING THIS EVENING. ACCOMPANYING THIS WILL BE AN INCREASE IN
MOIST UPGLIDE AROUND 300K OVER WRN NC... AS THE 850 MB ANTICYCLONE
JUST TO OUR WEST THIS MORNING SHIFTS ESE RESULTING IN RETURN FLOW
INTO THE WRN CAROLINAS. SO ALONG WITH THE THICKER MID/HIGH CLOUDS
SPREADING IN FROM THE WEST THIS EVENING AND TONIGHT... LOWER LEVEL
MOISTURE WILL INCREASE AS WELL ESPECIALLY IN AREAS WEST OF HIGHWAY
1. WILL BRING IN A CHANCE OF SHOWERS AND STORMS INTO THE WRN AND SW
CWA OVERNIGHT. LOWS 57-64 WITH CLOUDS AND THE STALLED FRONT KEEPING
TEMPS UP IN THE SOUTHERN CWA.
FOR SUNDAY/SUNDAY NIGHT: A DEEP POSITIVELY-TILTED MID LEVEL TROUGH
WHICH NOW STRETCHES FROM SRN NM ACROSS THE TX PANHANDLE INTO ERN KS
WILL SHIFT EASTWARD ACROSS TX SUNDAY/SUNDAY NIGHT... WHILE WEAK
VORTICITY SHEARS EASTWARD IN FAST WEST-EAST FLOW AHEAD OF THE TROUGH
INTO NC. AT THE SURFACE... THE FRONTAL ZONE WILL REMAIN STALLED NEAR
THE NC/SC STATE LINE THROUGH SUNDAY... BUT AS THE HIGH PRESSURE AREA
CENTERED TO OUR NORTH OVER SWRN PA PUSHES EASTWARD ACROSS THE MID
ATLANTIC REGION... THE LOW LEVEL FLOW WILL STEADILY VEER FROM
NORTHEASTERLY TO EASTERLY THEN FINALLY TO SOUTHEASTERLY... WITH THE
FRONTAL ZONE KICKING BACK NORTHWARD THROUGH THE SRN PIEDMONT/WRN
SANDHILLS. IN ADDITION TO THE IMPROVING MID LEVEL LIFT OVER NC...
UPPER DIVERGENCE WILL STEADILY INCREASE AS FLOW ALOFT SPEEDS UP TO
OUR NORTH AND NW. AND THE DEEPENING LOW LEVEL RETURN FLOW WILL
GENERATE IMPROVING MOIST UPGLIDE PARTICULARLY OVER WRN AND NRN NC...
ALONG THE NORTHEAST-DRIFTING AND WEAKENING SURFACE FRONTAL ZONE.
MOISTURE WILL CONTINUE TO DEEPEN WITH PRECIP WATER VALUES INCREASING
TO 150-200% OF NORMAL SUNDAY THROUGH SUNDAY NIGHT. EXPECT THE CHANCE
FOR SHOWERS AND A FEW STORMS TO INCREASE AND SPREAD FROM THE FAR WRN
CWA EARLY ACROSS THE REST OF THE WRN CWA THROUGH SUNDAY... THEN WE
SHOULD SEE SCATTERED SHOWERS AND STORMS AREAWIDE (YET STILL FOCUSED
ON THE WEST/NORTH WHERE MOISTURE TRANSPORT WILL BE HIGHEST) SUNDAY
EVENING AND NIGHT AS THE MOIST UPGLIDE AND UPPER LEVEL FORCING
COMPENSATES FOR THE LOSS OF DAYTIME HEATING AND INSTABILITY.
THICKNESSES STAY NEAR SEASONAL NORMALS BUT WITH CLOUDS OVERSPREADING
THE AREA... EXPECT HIGHS TO BE A BIT UNDER NORMAL... IN THE UPPER
70S TO LOWER 80S. LOWS 61-65. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 230 PM FRIDAY...
MONDAY THROUGH TUESDAY NIGHT:
A FAIR AMOUNT OF UNCERTAINTY PERSISTS WITH REGARD TO THE SPECIFICS
OF THE FORECAST IN THIS PERIOD...THOUGH OVERALL CHANCES FOR RAIN
(PERHAPS HEAVY) REMAIN HIGH...ESPECIALLY OVER WESTERN PORTIONS OF
THE STATE. UNCERTAINTY IN THE EVOLUTION OF THE UPPER LEVEL PATTERN
(AND ATTENDANT SURFACE PATTERN) OVER THE EASTERN CONUS IS LARGE DUE
TO SEVERAL FACTORS. A STALLED SOUTHERN STREAM WAVE OVER THE DESERT
SOUTHWEST IS EXPECTED TO BECOME PROGRESSIVE OVER THE WEEKEND...
TRACKING INTO THE LOWER MS RIVER VALLEY BY SUN NIGHT/MONDAY. AT THE
SAME TIME...A NORTHERN STREAM TROUGH IS PROGGED TO DIG SOUTHEAST
FROM CANADA INTO THE UPPER MIDWEST SUNDAY NIGHT...AMPLIFYING AS IT
DIGS SOUTHWARD/SSE INTO THE OH/TN VALLEYS MONDAY NIGHT AND TUESDAY.
IN ADDITION TO TYPICAL UNCERTAINTY IN THE EVOLUTION OF THE NORTHERN
STREAM PATTERN OVER CANADA (DATA SPARSE AREA) SEVERAL DAYS FROM
NOW...MATTERS ARE FURTHER COMPLICATED BY THE POTENTIAL INTERACTION
BETWEEN THE NORTHERN AND SOUTHERN STREAM WAVES EARLY NEXT WEEK. THE
EVOLUTION OF THE UPPER LEVEL PATTERN (IN ADDITION TO DEEP CONVECTION
UPSTREAM OF THE AREA OVER THE DEEP SOUTH/SOUTHEAST ON MONDAY) WILL
IN LARGE PART DETERMINE THE LOW-LEVEL HEIGHT/MSLP PATTERN OVER THE
CAROLINAS MON-TUE.
ALTHOUGH CONFIDENCE IN WIDESPREAD CLOUD COVER AND PRECIPITATION IS
HIGH...PARTICULARLY MONDAY NIGHT/TUESDAY...IT IS STILL DIFFICULT TO
DETERMINE THE NATURE OF THE SEVERE THREAT. HAVING SAID THAT...THE
12Z GFS/ECMWF ARE INDICATING STRONG/VEERING LOW-LEVEL FLOW (40-50 KT
AT H85) MONDAY NIGHT/TUESDAY...WITH RELATIVELY LARGE CLOCKWISE-
CURVED HODOGRAPHS /STRONG 0-1 KM SRH/ AND 35-45 KNOTS OF DEEP LAYER
SHEAR IN THE PRESENCE OF A VERY MOIST BOUNDARY LAYER (SFC DEWPOINTS
IN THE UPPER 60S) AND DEEP-LAYER ASCENT. WITH THE ABOVE IN MIND...
THE LATEST GUIDANCE SUGGESTS AN ISOLD TORNADO POTENTIAL MONDAY NIGHT
INTO TUESDAY...THOUGH THE GFS/ECMWF DIFFER ON THE TIMING...THE GFS
ARGUING EARLIER (ON MONDAY NIGHT) AND THE ECMWF LATER (TUE MORNING
INTO TUE AFTERNOON). HEAVY RAINFALL AND FLOODING WOULD ALSO BE
POSSIBLE MONDAY AFTERNOON THROUGH TUESDAY...ESPECIALLY IN THE W/NW
PIEDMONT...THOUGH THE BEST CHANCE SHOULD BE FURTHER WEST IN THE
FOOTHILLS/MOUNTAINS.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 315 PM FRIDAY...
WEDNESDAY THROUGH FRIDAY:
EXPECT HEIGHT RISES ALOFT AND HIGH PRESSURE BUILDING INTO THE AREA
WED/THU...WITH CLEARING SKIES AND TEMPERATURES 5-10F COOLER THAN
NORMAL. A DEEPENING UPPER LEVEL TROUGH IS POSSIBLE OVER THE GREAT
LAKES FRIDAY...WHICH WOULD PUSH ANOTHER FRONT TOWARD THE SOUTHERN
APPALACHIANS OVER THE WEEKEND. AT THIS TIME EXPECT PARTLY CLOUDY
SKIES AND NEAR NORMAL TEMPS ON FRIDAY. -VINCENT
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 215 AM SATURDAY...
THE MAIN CONCERN EARLY THIS MORNING IS AREAS OF FOG FORMING NEAR
KRWI. EXPECT IFR/LIFR CONDITIONS TO HOLD HERE FOR THE REMAINDER OF
THE NIGHT... GIVEN THE LIGHT WINDS AND CLEAR SKIES ALOFT ENSURING
GOOD RADIATIONAL COOLING AND LITTLE TO NO LOW LEVEL MIXING
VERTICALLY OR HORIZONTALLY. BANKS OF FOG... MAINLY NEAR BODIES OF
WATER... ARE POSSIBLE AT KRDU AND KFAY AS WELL PRIOR TO 12Z THIS
MORNING. A BRIEF PERIOD OF MVFR VSBY IS POSSIBLE AT THESE LOCATIONS.
LOWER NEAR-GROUND HUMIDITY AT KINT/KGSO WILL LIMIT ANY FOG
DEVELOPMENT AT THESE SITES.
ANY ADVERSE AVIATION CONDITIONS AT KRDU/KFAY WILL LIFT/MIX OUT BY
14Z. SIMILARLY... THE IFR/LIFR VSBY/CIG AT KRWI WILL SLOWLY IMPROVE
TO VFR THROUGH 15Z. AFTER THIS TIME... DAYTIME CUMULUS CLOUDS THIS
AFTERNOON AT ALL CENTRAL NC FORECAST SITES WILL BE BASED ABOVE 4
THOUSAND FT AGL. A WEAK FRONT WILL SINK SOUTHWARD THROUGH NC DURING
TODAY. WINDS OVER CENTRAL NC WILL BE LIGHT (UNDER 8 KTS OVERALL)
FROM THE NORTH THEN NORTHEAST THIS MORNING... EVENTUALLY SHIFTING TO
BE FROM THE EAST THEN ESE LATER TODAY AS HIGH PRESSURE TO OUR NORTH
BUILDS IN BRIEFLY BEHIND THE FRONT. ONLY ISOLATED SHOWERS ARE
EXPECTED THROUGH NIGHTFALL... HOWEVER CLOUDS BASED ABOVE 4 THOUSAND
FEET WILL STEADILY INCREASE IN NUMBER AND THICKEN BY EARLY
EVENING... RESULTING IN BROKEN TO OVERCAST VFR SKIES AT
KINT/KGSO/KRDU TOWARD 06Z WHILE SKIES REMAIN FAIR AT KRWI/KFAY. NO
FOG IS EXPECTED PRIOR TO 06Z TONIGHT.
LOOKING BEYOND 06Z TONIGHT... CIGS WILL LOWER TOWARD SUNDAY MORNING
BUT WILL MOSTLY REMAIN VFR... AS WILL VSBYS WITH LITTLE TO NO FOG
EXPECTED TO DEVELOP. A MID-UPPER TROUGH OVER NM/TX THIS MORNING WILL
MOVE SLOWLY EASTWARD SUNDAY THROUGH MONDAY AS A STRENGTHENING FRONT
APPROACHES FROM THE WEST... AND AVIATION CONDITIONS WILL SLOWLY
DETERIORATE IN THIS TIME FRAME... STARTING FIRST AT KINT/KGSO SUNDAY
NIGHT WITH MVFR CIGS/VSBYS IN SHOWERS/STORMS. MVFR TO IFR CONDITIONS
ARE LIKELY ALL ACROSS CENTRAL NC LATE MONDAY WELL INTO TUESDAY WITH
STRONG VEERING WINDS THROUGH THE LOWEST 10 THOUSAND FT. IMPROVING
CONDITIONS ARE EXPECTED WEDNESDAY WITH A COOLER INCOMING AIR MASS
BEHIND THE FRONT. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS NORMAN OK
1015 PM CDT SUN SEP 16 2012
.UPDATE...
NO SIGNIFICANT CHANGES TO THE FORECAST... ALTHOUGH HAVE UPDATED
THE CLOUD COVER SOMEWHAT. THE CURRENT OVERCAST IS ONLY SLOWLY
MOVING EAST. HRRR AND SOME OF THE NEW MOS GUIDANCE IS SUGGESTING
THAT STRATUS WILL REDEVELOP OVERNIGHT... MAINLY IN THE SOUTHEAST
THIRD OR SO OF THE AREA... BUT ALSO ACROSS THE WEST WHERE SKIES
ARE CURRENTLY CLEAR. IT REMAINS TO BE SEEN HOW WIDESPREAD IT WILL
BECOME... BUT WITH RELATIVELY LOW DEWPOINT DEPRESSIONS AND SOME
LOW-LEVEL MOISTURE ADVECTION WITH THE SOUTH WINDS... DO BELIEVE
THAT WE WILL SEE SOME STRATUS.
&&
.PREV DISCUSSION... /ISSUED 620 PM CDT SUN SEP 16 2012/
AVIATION...
MID/HIGH CLOUDS OVER EASTERN PART OF THE AREA SHOULD CONTINUE TO
GRADUALLY CLEAR FROM THE NW. COULD BE SOME PATCHY MVFR CONDITIONS
OVERNIGHT...MAINLY EAST BUT VFR CONDITIONS EXPECTED AREAWIDE BY
MONDAY MORNING. FRONT EXPECTED TO MOVE INTO NW OK MONDAY MORNING
AND THE PROGRESS THROUGH MOST SITES BY THE END OF THE PERIOD.
PRECIP CHANCES WITH THE FRONT TOO LOW TO INCLUDE IN TAFS ATTM.
PREV DISCUSSION... /ISSUED 224 PM CDT SUN SEP 16 2012/
DISCUSSION...
STILL DEALING WITH SLOW MOVING TROUGH ACROSS THE SOUTHERN PLAINS
AND TEXAS AND ASSOCIATED CLOUD COVER AND LIGHT RAIN ACROSS
SOUTHEAST OKLAHOMA. WILL KEEP SOME LOW POPS ACROSS THE SOUTHEAST
TONIGHT. MAY SEE SOME PATCHY FOG AGAIN LATE TONIGHT ACROSS PARTS
OF CENTRAL AND SOUTHEAST SECTIONS OF OKLAHOMA... BUT FOR NOW WILL
LEAVE OUT OF THE FORECAST.
MOST AREAS SHOULD SEE SUN ON MONDAY WITH WARMER TEMPS AHEAD OF
COLD FRONT WHICH WILL ENTER NORTHEAST OKLAHOMA BY LATE
MORNING/MIDDAY AND THEN MOVE QUICKLY SOUTH INTO NORTH TEXAS DURING
THE AFTN. CONT TO SEE VERY WEAK CONVERGENCE ALONG THIS FRONT...
HOWEVER MODELS STILL SHOW MODEST INSTABILITY AND MID-LEVEL LAPSE
RATES TO INITIATE STORMS. ALTHOUGH STILL APPEARS CHANCES WILL
REMAIN RATHER LOW WILL KEEP LOW POPS MONDAY AFTN AND MONDAY NIGHT
ON OUTSIDE CHANCE OF A STORM OR TWO ALONG AND BEHIND FRONT.
MILD MIDDLE OF THE WEEK WITH WARMING TREND BY LATE IN THE WEEK.
SOUTHERN PLAINS REMAIN IN NORTHWEST FLOW THROUGH NEXT WEEKEND.
HOWEVER MEDIUM RANGE MODELS CONT TO DISAGREE ON TIMING AND
STRENGTH OF SFC BOUNDARIES LATE THIS WEEK INTO NEXT WEEKEND. WILL
NOT MAKE ANY MAJOR CHANGES TO LATTER PART OF FORECAST AT THIS TIME
AS CONFIDENCE IN ANY PARTICULAR SCENARIO IS NOT HIGH. ESPECIALLY
WITH REGARDS TO PRECIP CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 60 85 53 77 / 0 20 20 0
HOBART OK 58 86 52 76 / 0 20 20 0
WICHITA FALLS TX 61 88 57 80 / 0 10 20 10
GAGE OK 52 82 46 78 / 0 10 10 0
PONCA CITY OK 59 80 49 75 / 0 20 10 0
DURANT OK 63 85 58 78 / 20 10 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
153 PM EDT SAT SEP 15 2012
.SYNOPSIS...
WEAK HIGH PRESSURE DRIFTS SLOWLY EAST REACHING THE COAST BY SUNDAY.
A STRONG LOW PRESSURE SYSTEM OFF THE GULF COAST WILL TRACK NORTHEAST
ACROSS EASTERN TENNESSEE BEFORE MEETING UP WITH A COLD FRONT MOVING
IN FROM THE WEST LATE TUESDAY. DRY HIGH PRESSURE WILL BUILD IN FORM
THE NORTH ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM EDT UPDATE...TRYING TO PINPOINT TIMING OF DIURNAL
CONVECTION. SATELLITE IMAGERY SHOWING CU ALREADY POPPING UP ON THE
HIGHEST RIDGETOPS. NAM AND RAP PROG SOUNDINGS SUPPORT PLENTY OF CU
BUT A WARM LAYER AROUND 600MB LIMITS THE INSTABILITY THROUGH MUCH OF
THE AFTERNOON...FINALLY COOLING A BIT AFTER ABOUT 20Z WHEN CAPE
INCREASES TO VALUES MORE IN LINE WITH MEASURABLE PRECIP. WILL DELAY
ONSET OF POPS A BIT BUT OTHERWISE...TODAY/S FORECAST LOOKS GOOD.
AT 230 AM EDT SATURDAY...A FLAT UPPER RIDGE WILL REMAIN OVER THE
SOUTHEAST TODAY AND TONIGHT....WHILE AN UPPER TROUGH CROSSES THE
NORTHEAST...AND A SOUTHERN STREAM TROUGH CROSSES TX. A COLD FRONT
WILL CROSS OUR AREA TODAY...STALLING IN A WEST TO EAST ORIENTATION
TO OUR SOUTH TONIGHT. MOISTURE ASSOCIATED WITH THE FRONT IS EXPECTED
TO SUPPORT CONVECTIVE DEVELOPMENT IN THE MOUNTAINS TODAY WITH MODEST
INSTABILITY. BY TONIGHT...ISENTROPIC UPGLIDE SETS UP OVER THE
BOUNDARY...SUPPORTING A SMALL CHANCE OF MORE WIDESPREAD
PRECIPITATION ACROSS THE AREA. TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM SATURDAY...AS PREVIOUSLY MENTIONED...THE HEAVY RAIN
EVENT LOOKS LIKELY THROUGH THE SHORT TERM PERIOD AS MODELS CONTINUE
TO SHOW A STRONG LOW PRESSURE SYSTEM OVER THE GULF COAST MOVING
ACROSS OUR CWA MONDAY THROUGH TUESDAY. BY SUNDAY...EXPECT INCREASING
MOIST SOUTHERLY FLOW ACROSS THE REGION AS THE HIGH PRESSURE SHIFTS
EAST AND THE LOW PRESSURE SLOWLY APPROACHES FROM THE GULF COAST. AS
A RESULT...MOISTURE WILL DEEPEN AND INSTABILITY WILL BE GOOD ENOUGH
TO TRIGGER WIDESPREAD SHOWERS AND THUNDERSTORMS ON SUNDAY. AS THE
SOUTHERN STREAM SHORT WAVE TROUGH AND ASSOCIATED LOW PRESSURE SYSTEM
MOVE ACROSS AL/GA MONDAY...STRONG 250 MB UPPER LEVEL JET DEVELOPS
JUST TO OUR NORTHEAST AND LINGERS THROUGH TUESDAY ALLOWING GOOD
UPPER DIVERGENCE ACROSS OUR CWA. WITH CONTINUED DEEPENING
MOISTURE...GOOD UPPER LEVEL FORCING AND INSTABILITY...WILL KEEP
LIKELY POPS ON MONDAY.
THE HEAVIEST RAIN WILL OCCUR MONDAY NIGHT THROUGH TUESDAY MORNING AS
THE CENTER OF LOW PRESSURE MOVES ACROSS OUR CWA. THE UPPER FORCING
WILL BE THE STRONGEST IN THIS PERIOD WITH THE AID OF WARM AIR
ADVECTION DRIVEN BY STRONG 850 MB SOUTHERLY JET...POSITIVE VORTICITY
ADVECTION AND GOOD UPPER LEVEL DIVERGENCE. THE LATEST MODEL RUNS
SHOW HIGHER TOTAL QPF VALUES WITH 2-4 INCHES OVER THE PIEDMONT AND
HIGHER AMOUNTS IN THE MOUNTAINS. SEVERE WEATHER IS NOT OUT OF THE
QUESTION AS MODELS CONTINUE TO SHOW 0-3 KM BULK SHEAR MAGNITUDE OF
25-30KTS OVERLAPPING DECENT CAPE VALUES OVER OUR AREA. PRECIP WILL
DECREASE FROM WEST TO EAST TUESDAY AS AN ASSOCIATED COLD FRONT
PUSHES SE ACROSS THE REGION AND DRIER AIRMASS MOVES IN FROM THE NW
BY LATE TUESDAY. TEMPERATURES WILL BE NEAR NORMAL ON SUNDAY BEFORE
DROPPING BY 3-5 DEGREES BELOW NORMAL MON/TUE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 130 PM SATURDAY...THE MEDIUM RANGE LOOKS LIKE IT WILL BE
DOMINATED BY A LARGE UPPER TROF OVER THE EASTERN HALF OF NORTH
AMERICA. IN THE WAKE OF A DEPARTING SHORT WAVE TROF...A SHORT WAVE
RIDGE IMPOSED ON THE OVERALL LONG WAVE TROF WILL MOVE OVERHEAD
WEDNESDAY AND WEDNESDAY NIGHT. THIS WILL SUPPORT DRY HIGH PRESSURE
FOR THE END OF THE WORK WEEK. BY FRIDAY...ANOTHER STRONG SHORT WAVE
DIVING DOWN INTO THE TROF WILL CARVE OUT A NEW CLOSED LOW OVER THE
UPPER MIDWEST THAT IS FCST TO DEEPEN OVER THE WRN GREAT LAKES FRIDAY
NIGHT AND SATURDAY IN THE ECMWF. MEANWHILE...THE OPERATIONAL GFS
KEEPS THE UPPER TROF OPEN AND THUS MORE PROGRESSIVE. THE OLD GFS
ENSEMBLE MEAN GIVES MORE CONFIDENCE TO SOMETHING MORE LIKE THE ECMWF
AS IT KEEPS THE UPPER TROF AXIS TO OUR WEST ON SATURDAY...SO I AM
INCLINED TO FOLLOW THE ECMWF WITH THE TIMING OF THE NEXT FRONT. HPC
HAS THE POSITION W OF THE MTNS AT 12Z SATURDAY. THE UPPER PATTERN
SUGGESTS A SLOWER MOVEMENT OF THE FRONT AS THE TROF AXIS WILL STILL
BE OUT OVER THE OH/MID MS VALLEY BY THE END OF THE DAY. SO...THE
FCST RAMPS UP TO A CHANCE POP FROM W TO E LATE FRIDAY NIGHT AND INTO
SATURDAY AND KEEPS THAT CHANCE THROUGH THE DAY. MOISTURE FROM THE
GULF REMAINS CUT OFF FROM THIS SYSTEM SO IT SHOULD NOT BE THE RAIN
MAKER EXPECTED OF THE SYSTEM EARLY IN THE WEEK. WITH THE UPPER
PATTERN RESEMBLING SOMETHING MORE WINTER-LIKE...TEMPS WILL CONTINUE
TO RUN A CATEGORY OR TWO BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT...BIGGEST CONCERN THIS AFTERNOON WILL BE DIURNAL CUMULUS.
TOO DRY IN THE LOWER LEVELS TO EXPECT MUCH MORE THAN SCATTERED CU AT
VFR LEVEL TO DEVELOP UNTIL EARLY EVENING WHEN MOISTURE WILL INCREASE
AND A CEILING IS EXPECTED TO FORM BUT STILL AT VFR LEVEL. WINDS WILL
REMAIN LIGHT AND NORTHEASTERLY THEN BECOME MORE EASTERLY TONIGHT.
NOT ANTICIPATING ANY FLIGHT RESTRICTIONS OVERNIGHT DUE TO CIG OR
FOG...THOUGH PRECIPITATION CHANCES INCREASE OVERNIGHT AND SCATTERED
SHOWERS MAY PRODUCE BRIEF DROPS TO MVFR EARLY TOMORROW MORNING.
SHOWERS AND THUNDERSTORMS SHOULD INCREASE IN COVERAGE AFTER DAYBREAK
AND CEILINGS WILL MOST LIKELY LOWER WITH THE INCREASING DEEP LAYER
MOISTURE. KEPT CIG VFR TOMORROW MORNING WITH A MENTION OF VCSH UNTIL
CONFIDENCE INCREASES WITH THE PRECIP...AND OF COURSE WE MAY NEED TO
UPGRADE TO VCTS IF CONFIDENCE GETS SUFFICIENTLY HIGH THAT PRECIP
WILL OCCUR AT THE AIRFIELD.
ELSEWHERE...BKN CEILINGS ARE LIKELY TO DEVELOP OVER MUCH OF THE MTNS
THIS AFTN WITH SCATTERED SHOWERS STILL EXPECTED TO DEVELOP AS WELL.
COOLING IN THE MID TO UPPER ATMOSPHERE AFTER PEAK HEATING MAY
ACTUALLY CAUSE THE PEAK OF ACTIVITY TO BE A LITTLE LATER THAN
USUAL...BUT CONVECTION SHOULD DIMINISH AFTER SUNSET THOUGH CLOUD
COVER WILL GRADUALLY INCREASE INTO TOMORROW. MENTIONED VCSH FOR A
TIME AT KAVL THIS AFTN. CONVECTION A CONCERN ONCE AGAIN TOMORROW
WITH GREATER INSTABILITY WARRANTING A THUNDER MENTION. INCREASING
DEEP LAYER MOISTURE SHOULD ENABLE CIGS TO LOWER TO AT LEAST LOW
VFR...NOT CONFIDENT ENOUGH AT THIS POINT TO GO WITH MVFR CIGS THOUGH
THEY CANNOT BE RULED OUT.
OUTLOOK...A SLOW MOVING COLD FRONT WILL BE STALLED TO OUR SOUTH
SUNDAY. LOW PRESSURE WILL SUPPLY DEEP MOISTURE ACROSS THE REGION
SUNDAY NIGHT THROUGH MONDAY...AND RESTRICTIONS ARE LIKELY AT THAT
TIME. A STRONG COLD FRONT IS EXPECTED TO REACH THE REGION BY MID
WEEK...BRINGING IN DRIER AIR.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...JOH
LONG TERM...PM
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1044 AM EDT SAT SEP 15 2012
.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL REMAIN IN PLACE OVER THE REGION
TODAY THROUGH SUNDAY. STRONG LOW PRESSURE SYSTEM OFF THE GULF COAST
WILL TRACK NORTHEAST ACROSS EASTERN TENNESSEE BEFORE A COLD FRONT
MOVES IN FROM THE WEST TUESDAY NIGHT. DRY HIGH PRESSURE WILL BUILD
IN FORM THE NORTH ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM EDT UPDATE...TRYING TO PINPOINT TIMING OF DIURNAL
CONVECTION. SATELLITE IMAGERY SHOWING CU ALREADY POPPING UP ON THE
HIGHEST RIDGETOPS. NAM AND RAP PROG SOUNDINGS SUPPORT PLENTY OF CU
BUT A WARM LAYER AROUND 600MB LIMITS THE INSTABILITY THROUGH MUCH OF
THE AFTERNOON...FINALLY COOLING A BIT AFTER ABOUT 20Z WHEN CAPE
INCREASES TO VALUES MORE IN LINE WITH MEASURABLE PRECIP. WILL DELAY
ONSET OF POPS A BIT BUT OTHERWISE...TODAY/S FORECAST LOOKS GOOD.
AT 230 AM EDT SATURDAY...A FLAT UPPER RIDGE WILL REMAIN OVER THE
SOUTHEAST TODAY AND TONIGHT....WHILE AN UPPER TROUGH CROSSES THE
NORTHEAST...AND A SOUTHERN STREAM TROUGH CROSSES TX. A COLD FRONT
WILL CROSS OUR AREA TODAY...STALLING IN A WEST TO EAST ORIENTATION
TO OUR SOUTH TONIGHT. MOISTURE ASSOCIATED WITH THE FRONT IS EXPECTED
TO SUPPORT CONVECTIVE DEVELOPMENT IN THE MOUNTAINS TODAY WITH MODEST
INSTABILITY. BY TONIGHT...ISENTROPIC UPGLIDE SETS UP OVER THE
BOUNDARY...SUPPORTING A SMALL CHANCE OF MORE WIDESPREAD
PRECIPITATION ACROSS THE AREA. TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM SATURDAY...AS PREVIOUSLY MENTIONED...THE HEAVY RAIN
EVENT LOOKS LIKELY THROUGH THE SHORT TERM PERIOD AS MODELS CONTINUE
TO SHOW A STRONG LOW PRESSURE SYSTEM OVER THE GULF COAST MOVING
ACROSS OUR CWA MONDAY THROUGH TUESDAY. BY SUNDAY...EXPECT INCREASING
MOIST SOUTHERLY FLOW ACROSS THE REGION AS THE HIGH PRESSURE SHIFTS
EAST AND THE LOW PRESSURE SLOWLY APPROACHES FROM THE GULF COAST. AS
A RESULT...MOISTURE WILL DEEPEN AND INSTABILITY WILL BE GOOD ENOUGH
TO TRIGGER WIDESPREAD SHOWERS AND THUNDERSTORMS ON SUNDAY. AS THE
SOUTHERN STREAM SHORT WAVE TROUGH AND ASSOCIATED LOW PRESSURE SYSTEM
MOVE ACROSS AL/GA MONDAY...STRONG 250 MB UPPER LEVEL JET DEVELOPS
JUST TO OUR NORTHEAST AND LINGERS THROUGH TUESDAY ALLOWING GOOD
UPPER DIVERGENCE ACROSS OUR CWA. WITH CONTINUED DEEPENING
MOISTURE...GOOD UPPER LEVEL FORCING AND INSTABILITY...WILL KEEP
LIKELY POPS ON MONDAY.
THE HEAVIEST RAIN WILL OCCUR MONDAY NIGHT THROUGH TUESDAY MORNING AS
THE CENTER OF LOW PRESSURE MOVES ACROSS OUR CWA. THE UPPER FORCING
WILL BE THE STRONGEST IN THIS PERIOD WITH THE AID OF WARM AIR
ADVECTION DRIVEN BY STRONG 850 MB SOUTHERLY JET...POSITIVE VORTICITY
ADVECTION AND GOOD UPPER LEVEL DIVERGENCE. THE LATEST MODEL RUNS
SHOW HIGHER TOTAL QPF VALUES WITH 2-4 INCHES OVER THE PIEDMONT AND
HIGHER AMOUNTS IN THE MOUNTAINS. SEVERE WEATHER IS NOT OUT OF THE
QUESTION AS MODELS CONTINUE TO SHOW 0-3 KM BULK SHEAR MAGNITUDE OF
25-30KTS OVERLAPPING DECENT CAPE VALUES OVER OUR AREA. PRECIP WILL
DECREASE FROM WEST TO EAST TUESDAY AS AN ASSOCIATED COLD FRONT
PUSHES SE ACROSS THE REGION AND DRIER AIRMASS MOVES IN FROM THE NW
BY LATE TUESDAY. TEMPERATURES WILL BE NEAR NORMAL ON SUNDAY BEFORE
DROPPING BY 3-5 DEGREES BELOW NORMAL MON/TUE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 2 AM SATURDAY...THE LATEST MEDIUM RANGE MODELS CONTINUE TO
INDICATE THAT DRY SURFACE HIGH PRESSURE WILL BUILD IN FROM THE NORTH
WEDNESDAY AND REMAIN IN PLACE THROUGH FRIDAY. THIS WILL RESULT IN
CONTINUED DRY WEATHER AND COOL TEMPERATURES ACROSS THE REGION
THROUGH FRIDAY. TEMPERATURES WILL STAY 5-10 DEGREES BELOW NORMAL
WED/THU WITH AFTERNOON HIGHS IN THE MID 70S OVER THE PIEDMONT AND
60S IN THE MOUNTAINS. WITH COLD AIR ADVECTION AND CLEAR
SKIES...OVERNIGHT LOWS WILL PLUNGE INTO THE LOW 50S OVER THE
PIEDMONT AND 40S IN THE VALLEYS/MOUNTAINS THROUGH THE PERIOD.
TEMPERATURES SHOULD RISE BY 3-5 DEGREES F BY FRIDAY AS HIGH PRESSURE
SHIFTS EAST AND LLVL FLOW BECOMES SOUTHERLY. ANOTHER COLD FONT WILL
APPROACH THE APPALACHIANS BY FRIDAY NIGHT/SATURDAY MORNING FOR LOW
END/SLIGHT CHANCE POP THERE.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...ALREADY MIXING DOWN SOME STRONGER WINDS NEAR 8 KT PER SFC
OBS. THIS IS SUPPORTED BY VAD WINDS FROM TERMINAL DOPPLER AND GOES
SOUNDING THERMAL PROFILE. DESPITE DEEP MIXING TODAY...WINDS IN THE
MIXED LAYER WILL BE FAIRLY WEAK AND EXCEPT FOR OCCASIONAL GUSTS
ABOVE 10 KT DOUBT WE WILL SEE MUCH FURTHER INCREASE FROM CURRENT
OBS. ALSO IT APPEARS TOO DRY IN THE LOW LEVELS TO GET MUCH CUMULUS
DEVELOPMENT BUT A FEW VFR CU ARE NOT OUT OF THE QUESTION THIS
AFTERNOON.
ELSEWHERE...SOME FOG REMAINS IN THE MOUNTAIN VALLEYS AS OF 1030 AM
EDT BUT VSBY AT ALL OBS SITES HAS IMPROVED TO VFR. ENOUGH LOW LEVEL
MOISTURE WILL RETURN TO THE MOUNTAINS FOR A CHANCE OF THUNDER THIS
AFTERNOON...BUT NOT ENOUGH OF A CHANCE TO MENTION AT KAVL.
PRECIPITATION CHANCES WERE LOWERED SLIGHTLY FROM PREVIOUS FORECAST
AND DELAYED UNTIL AFTER 18Z. LOW LEVEL MOISTURE WILL INCREASE ACROSS
THE AREA THIS EVENING AS ISENTROPIC UPGLIDE SETS UP OVER THE
STALLING FRONT TO OUR SOUTH...BRINGING LOW VFR CIGS TO THE AREA.
PRECIPITATION CHANCES ARE TOO LOW TO MENTION IN THE TAFS. THE MODEL
GUIDANCE CONSENSUS FAVORS MVFR FOG AT MOST SITES SUNDAY
MORNING...AND IFR AT KAVL. WITH LIMITED CONFIDENCE...VFR WILL BE
MAINTAINED FOR NOW. WINDS WILL VEER FROM N TO NE TODAY...THEN GO
CALM TONIGHT.
OUTLOOK...A SLOW MOVING COLD FRONT WILL BE STALLED TO OUR SOUTH
SUNDAY. LOW PRESSURE WILL SUPPLY DEEP MOISTURE ACROSS THE REGION
SUNDAY NIGHT THROUGH MONDAY...AND RESTRICTIONS ARE LIKELY. A STRONG
COLD FRONT IS EXPECTED TO REACH THE REGION BY MID WEEK...BRINGING IN
DRIER AIR.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...JOH
LONG TERM...JOH
AVIATION...JAT/WIMBERLEY
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1047 PM CDT SUN SEP 16 2012
.DISCUSSION.../ISSUED AT 955 PM CDT/
SURFACE FRONT CONTINUES TO SHIFT SOUTH ACROSS THE CWA AT THIS
TIME...WITH IT CURRENTLY ABOUT 25 MILES SOUTH OF SIOUX FALLS. WILL
SEE BLUSTERY NORTHEAST WINDS FOR A FEW HOURS AFTER THE FRONTAL
PASSAGE...WITH GUSTS UP TO 30 MPH. JUST STARTING TO SEE SOME SHOWER
AND THUNDERSTORM DEVELOPMENT NEAR HURON AS THE UPPER LEVEL SUPPORT
APPROACHES AND 700MB FRONT MOVES THROUGH. HRRR SEEMS TO HAVE A GOOD
HANDLE ON THIS DEVELOPMENT AND LOOKS REASONABLE WITH ITS EVOLUTION
OF THINGS TONIGHT. INITIALLY EXPECT MOST OF THE ACTIVITY TO STAY
ALONG AND NORTH OF HIGHWAY 34...CLOSEST TO BEST THETAE ADVECTION AT
700MB. SHOULD SEE ACTIVITY BEGIN TO PUSH SOUTHEAST AFTER 3 AM...WITH
THE BEST THREAT FROM YANKTON TO SIOUX FALLS AND POINTS EAST. HRRR
SHOWING ABOUT 500 J/KG OF ELEVATED CAPE FROM HIGHWAY 14 AND POINTS
SOUTH...AND GIVEN CURRENT LIGHTNING ACTIVITY THIS IS PROBABLY PRETTY
ACCURATE. SO EMBEDDED THUNDER IS LIKELY WITH ANY ACTIVITY THROUGH
EARLY MORNING...BEFORE INSTABILITY DISSIPATES...WITH JUST LIGHT
SHOWERS LINGERING ACROSS NORTHWEST IOWA UNTIL AROUND 10 AM. /CHENARD
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
A COLD FRONT MOVING THROUGH NORTHWEST IOWA AT 04Z AND SHOULD EXIT
CWA BY 09Z. SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR
BEHIND THIS FRONT AND SPREAD SOUTHEAST. THE SHOWERS SHOULD EXIT CWA
BY 15Z. OCCASIONAL MVFR CEILINGS BEHIND THE FRONT 06Z-18Z.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 311 PM CDT/
FRONTAL BOUNDARY PRESENTLY ORIENTED FROM JUST EAST OF MARSHALL BACK
TO SOUTHERN CHARLES MIX COUNTY THIS AFTERNOON...AND CONTINUING TO
EVER SO SLOWLY SAG TO THE SOUTHEAST. STILL NOT EXPECTING
PRECIPITATION TO DEVELOP UNTIL LATER THIS EVENING AS A SHORTWAVE
BEGINS TO ENCROACH ON OUR WESTERN ZONES. CHANCES OF SHOWERS WILL
INCREASE THROUGH THE EVENING...WITH THE BEST SHOT GENERALLY NORTH OF
INTERSTATE 90 OVERNIGHT...CLOSER TO THE MAIN WAVE/BEST UPPER LEVEL
DIVERGENCE/AND STRENGTHENING MIDLEVEL FRONTOGENESIS OVER THAT AREA.
CONTAINED THUNDER TO ONLY AN ISOLATED CHANCE IN OUR WEST EARLY IN
THE EVENING...THEN ALONG THE LEADING EDGE OF THE PRECIPITATION
SHIELD LATER IN THE EVENING WITH THE BETTER INSTABILITY REMAINING
ALONG AND OUT AHEAD OF THE FRONT...AND MOST OF THE PRECIPITATION
OCCURRING POST FRONTAL. WILL ALSO SEE NORTHERLY WINDS PICK UP
THROUGH THE NIGHT BEHIND THE SYSTEM IN A STRONG COLD AIR ADVECTION
REGIME AND A TIGHTENING GRADIENT. COOLER TEMPERATURES WILL FILTER IN
BEHIND THE FRONT...WITH LOWS IN THE MID AND UPPER 40S ACROSS OUR
NORTH AND WEST...TO THE LOWER 50S TO THE SOUTHEAST.
LINGERING SHOWERS WILL BE FOUND IN OUR SOUTHEAST ON MONDAY
MORNING...BEFORE THE BETTER DYNAMICS AND MOISTURE PULL OFF TO THE
EAST BY LATE MORNING. IT WILL STILL BE FAIRLY BREEZY ON MONDAY WITH
CONTINUING COLD AIR ADVECTION/RAPID SURFACE PRESSURE RISES/GOOD
MIXING...THOUGH BEGINNING TO TAPER DOWN A BIT IN OUR WEST DURING THE
AFTERNOON AS THE HIGHER PRESSURE BUILDS IN AND THE GRADIENT BEGINS
TO RELAX. IT WILL BE A MUCH COOLER DAY WITH PROGGED 850 MB TEMPS TO
ONLY BE IN THE SINGLE DIGITS C...WITH HIGHS RANGING FROM THE UPPER
50S NORTHEAST TO THE MID 60S THROUGH THE MISSOURI RIVER CORRIDOR.
/JM
THE REST OF THE FORECAST THROUGH NEXT WEEKEND IS MARKED BY A HIGHLY
AMPLIFIED FLOW ALOFT...WITH LARGE UPPER TROUGHING SITUATED OVER
EASTERN CANADA AND THE U.S. PROVIDING OUR AREA WITH PERIODIC SHOTS
OF REINFORCING COOL AIR. MONDAY NIGHT WILL STILL HAVE A POTENTIAL
FOR FROST GENERALLY ALONG AND EAST OF THE JAMES RIVER VALLEY.
DECIDED TO ADD SOME AREAS OF FROST TO THE FORECAST FOR LATE MONDAY
NIGHT AND VERY EARLY TUESDAY WHERE THE TEMPERATURES ARE FORECAST TO
DROP TO ABOUT 33 DEGREES. IN ADDITION...THE DEW POINT VALUES AT THE
SURFACE LOOK TO BE RELATIVELY HIGH...THEREFORE THE POTENTIAL FOR
ACTUAL FROST TO DEVELOP IS CERTAINLY THERE. SOMETIMES THE AIR IS SO
DRY THAT YOU CAN DIP CLOSE TO OR BELOW FREEZING WITH NO CHANCE FOR
FROST BUT THIS DOES NOT LOOK TO BE THE CASE. TUESDAY RIGHT NOW LOOKS
LIKE TO BE A PLEASANT EARLY FALL DAY.
THEN THE NEXT UPPER WAVE MOVES SOUTHEAST FROM SOUTHERN CANADA DOWN
THE LONG WAVE TROUGH...AFFECTING OUR AREA WITH A DRY COLD FRONT ON
WEDNESDAY. GOOD MIXING POTENTIAL ON WEDNESDAY WILL LIKELY KICK THE
WINDS UP INTO THE 15 TO 30 MPH CATEGORY...WITH MINIMUM HUMIDITY
VALUES ONCE AGAIN DROPPING TO BELOW 30 PERCENT. SO WEDNESDAY WILL BE
OUR NEXT DAY WITH SERIOUS FIRE WEATHER CONCERNS SINCE SOME LOCATIONS
WILL BE CLOSE TO RED FLAG.
IN THE EXTENDED THURSDAY THROUGH SUNDAY...LITTLE OR NO CHANCE FOR
MEASURABLE RAINFALL CONTINUES. THERE CONTINUES TO BE SOME
DISCREPANCY BETWEEN THE GFS...AND THE ECMWF/GEM GLOBAL SOLUTIONS IN
HANDLING THE LONG WAVE PATTERN. THE GFS CONTINUES ITS TREND OF
YESTERDAY IN SLOWLY SHIFTING THE LONG WAVE TROUGH EASTWARD NEXT
WEEKEND. THE ECMWF AND GEM GLOBAL ARE SLOWER...WHICH WOULD KEEP OUR
AREA A LITTLE COOLER. THE GFS AT LEAST IN THE PAST HAS HAD A PROBLEM
IN PROGRESSING HUDSON BAY UPPER TROUGHS EASTWARD TOO QUICKLY...SO
BELIEVE THAT THE OTHER MODELS ARE PROBABLY MORE CORRECT. TRENDED
SOME LOWS A LITTLE COOLER THAN CONSENSUS GUIDANCE VALUES BUT FOR NOW
THE HIGHS DID NOT LOOK TOO BAD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
955 PM CDT SUN SEP 16 2012
.DISCUSSION.../ISSUED AT 955 PM CDT/
SURFACE FRONT CONTINUES TO SHIFT SOUTH ACROSS THE CWA AT THIS
TIME...WITH IT CURRENTLY ABOUT 25 MILES SOUTH OF SIOUX FALLS. WILL
SEE BLUSTERY NORTHEAST WINDS FOR A FEW HOURS AFTER THE FRONTAL
PASSAGE...WITH GUSTS UP TO 30 MPH. JUST STARTING TO SEE SOME SHOWER
AND THUNDERSTORM DEVELOPMENT NEAR HURON AS THE UPPER LEVEL SUPPORT
APPROACHES AND 700MB FRONT MOVES THROUGH. HRRR SEEMS TO HAVE A GOOD
HANDLE ON THIS DEVELOPMENT AND LOOKS REASONABLE WITH ITS EVOLUTION
OF THINGS TONIGHT. INITIALLY EXPECT MOST OF THE ACTIVITY TO STAY
ALONG AND NORTH OF HIGHWAY 34...CLOSEST TO BEST THETAE ADVECTION AT
700MB. SHOULD SEE ACTIVITY BEGIN TO PUSH SOUTHEAST AFTER 3 AM...WITH
THE BEST THREAT FROM YANKTON TO SIOUX FALLS AND POINTS EAST. HRRR
SHOWING ABOUT 500 J/KG OF ELEVATED CAPE FROM HIGHWAY 14 AND POINTS
SOUTH...AND GIVEN CURRENT LIGHTNING ACTIVITY THIS IS PROBABLY PRETTY
ACCURATE. SO EMBEDDED THUNDER IS LIKELY WITH ANY ACTIVITY THROUGH
EARLY MORNING...BEFORE INSTABILITY DISSIPATES...WITH JUST LIGHT
SHOWERS LINGERING ACROSS NORTHWEST IOWA UNTIL AROUND 10 AM. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 311 PM CDT/
FRONTAL BOUNDARY PRESENTLY ORIENTED FROM JUST EAST OF MARSHALL BACK
TO SOUTHERN CHARLES MIX COUNTY THIS AFTERNOON...AND CONTINUING TO
EVER SO SLOWLY SAG TO THE SOUTHEAST. STILL NOT EXPECTING
PRECIPITATION TO DEVELOP UNTIL LATER THIS EVENING AS A SHORTWAVE
BEGINS TO ENCROACH ON OUR WESTERN ZONES. CHANCES OF SHOWERS WILL
INCREASE THROUGH THE EVENING...WITH THE BEST SHOT GENERALLY NORTH OF
INTERSTATE 90 OVERNIGHT...CLOSER TO THE MAIN WAVE/BEST UPPER LEVEL
DIVERGENCE/AND STRENGTHENING MIDLEVEL FRONTOGENESIS OVER THAT AREA.
CONTAINED THUNDER TO ONLY AN ISOLATED CHANCE IN OUR WEST EARLY IN
THE EVENING...THEN ALONG THE LEADING EDGE OF THE PRECIPITATION
SHIELD LATER IN THE EVENING WITH THE BETTER INSTABILITY REMAINING
ALONG AND OUT AHEAD OF THE FRONT...AND MOST OF THE PRECIPITATION
OCCURRING POST FRONTAL. WILL ALSO SEE NORTHERLY WINDS PICK UP
THROUGH THE NIGHT BEHIND THE SYSTEM IN A STRONG COLD AIR ADVECTION
REGIME AND A TIGHTENING GRADIENT. COOLER TEMPERATURES WILL FILTER IN
BEHIND THE FRONT...WITH LOWS IN THE MID AND UPPER 40S ACROSS OUR
NORTH AND WEST...TO THE LOWER 50S TO THE SOUTHEAST.
LINGERING SHOWERS WILL BE FOUND IN OUR SOUTHEAST ON MONDAY
MORNING...BEFORE THE BETTER DYNAMICS AND MOISTURE PULL OFF TO THE
EAST BY LATE MORNING. IT WILL STILL BE FAIRLY BREEZY ON MONDAY WITH
CONTINUING COLD AIR ADVECTION/RAPID SURFACE PRESSURE RISES/GOOD
MIXING...THOUGH BEGINNING TO TAPER DOWN A BIT IN OUR WEST DURING THE
AFTERNOON AS THE HIGHER PRESSURE BUILDS IN AND THE GRADIENT BEGINS
TO RELAX. IT WILL BE A MUCH COOLER DAY WITH PROGGED 850 MB TEMPS TO
ONLY BE IN THE SINGLE DIGITS C...WITH HIGHS RANGING FROM THE UPPER
50S NORTHEAST TO THE MID 60S THROUGH THE MISSOURI RIVER CORRIDOR.
/JM
THE REST OF THE FORECAST THROUGH NEXT WEEKEND IS MARKED BY A HIGHLY
AMPLIFIED FLOW ALOFT...WITH LARGE UPPER TROUGHING SITUATED OVER
EASTERN CANADA AND THE U.S. PROVIDING OUR AREA WITH PERIODIC SHOTS
OF REINFORCING COOL AIR. MONDAY NIGHT WILL STILL HAVE A POTENTIAL
FOR FROST GENERALLY ALONG AND EAST OF THE JAMES RIVER VALLEY.
DECIDED TO ADD SOME AREAS OF FROST TO THE FORECAST FOR LATE MONDAY
NIGHT AND VERY EARLY TUESDAY WHERE THE TEMPERATURES ARE FORECAST TO
DROP TO ABOUT 33 DEGREES. IN ADDITION...THE DEW POINT VALUES AT THE
SURFACE LOOK TO BE RELATIVELY HIGH...THEREFORE THE POTENTIAL FOR
ACTUAL FROST TO DEVELOP IS CERTAINLY THERE. SOMETIMES THE AIR IS SO
DRY THAT YOU CAN DIP CLOSE TO OR BELOW FREEZING WITH NO CHANCE FOR
FROST BUT THIS DOES NOT LOOK TO BE THE CASE. TUESDAY RIGHT NOW LOOKS
LIKE TO BE A PLEASANT EARLY FALL DAY.
THEN THE NEXT UPPER WAVE MOVES SOUTHEAST FROM SOUTHERN CANADA DOWN
THE LONG WAVE TROUGH...AFFECTING OUR AREA WITH A DRY COLD FRONT ON
WEDNESDAY. GOOD MIXING POTENTIAL ON WEDNESDAY WILL LIKELY KICK THE
WINDS UP INTO THE 15 TO 30 MPH CATEGORY...WITH MINIMUM HUMIDITY
VALUES ONCE AGAIN DROPPING TO BELOW 30 PERCENT. SO WEDNESDAY WILL BE
OUR NEXT DAY WITH SERIOUS FIRE WEATHER CONCERNS SINCE SOME LOCATIONS
WILL BE CLOSE TO RED FLAG.
IN THE EXTENDED THURSDAY THROUGH SUNDAY...LITTLE OR NO CHANCE FOR
MEASURABLE RAINFALL CONTINUES. THERE CONTINUES TO BE SOME
DISCREPANCY BETWEEN THE GFS...AND THE ECMWF/GEM GLOBAL SOLUTIONS IN
HANDLING THE LONG WAVE PATTERN. THE GFS CONTINUES ITS TREND OF
YESTERDAY IN SLOWLY SHIFTING THE LONG WAVE TROUGH EASTWARD NEXT
WEEKEND. THE ECMWF AND GEM GLOBAL ARE SLOWER...WHICH WOULD KEEP OUR
AREA A LITTLE COOLER. THE GFS AT LEAST IN THE PAST HAS HAD A PROBLEM
IN PROGRESSING HUDSON BAY UPPER TROUGHS EASTWARD TOO QUICKLY...SO
BELIEVE THAT THE OTHER MODELS ARE PROBABLY MORE CORRECT. TRENDED
SOME LOWS A LITTLE COOLER THAN CONSENSUS GUIDANCE VALUES BUT FOR NOW
THE HIGHS DID NOT LOOK TOO BAD.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
A COLD FRONT ALONG I90 AT 23Z WILL CONTINUE TO DROP SOUTH OVERNIGHT
AND WILL EXIT CWA BY 09Z. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL DEVELOP BEHIND THIS FRONT AFTER 03Z AND SPREAD
SOUTHEAST. THE SHOWERS SHOULD EXIT CWA BY 15Z. OCCASIONAL MVFR
CEILINGS BEHIND THE FRONT 06Z-18Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
833 PM CDT SUN SEP 16 2012
.UPDATE...
HIGH BASED SHOWERS ALONG THE ND BORDER WERE HAVING A HARD TIME
MAKING IT SOUTHWARD THIS EVENING. ALTHOUGH...MORE HAD DEVELOPED
INTO NORTH CENTRAL SD THIS EVENING. STILL EXPECT NEW DEVELOPMENT
THIS EVENING IN NORTHEAST SD AND WEST CENTRAL MN BASED ON THE
LATEST HRRR MODEL. THUS...WILL LEAVE POPS AS IS FOR NOW THROUGH
THE EVENING AND OVERNIGHT.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
FORECAST CHALLENGES INCLUDE PRECIPITATION AMOUNTS TONIGHT AND LOW
TEMPERATURES MONDAY NIGHT.
CURRENTLY...A LONGWAVE TROF OVER SOUTH CENTRAL CANADA WITH
EMBEDDED SHORTWAVES IS PROPAGATING SOUTHEAST TOWARD THE NORTHERN
PLAINS. AT THE SURFACE...A COLD FRONT COMPLETED ITS DRY PASSAGE
THROUGH THE CWA EARLIER THIS MORNING WITH BREEZY/WINDY NORTHEAST
WINDS DEVELOPING BEHIND IT. THE COMBINATION OF INCREASING
CLOUDINESS AND THE DEVELOPING LOW LEVEL CAA HAS TEMPERATURES
BASICALLY HOLDING STEADY IN A RANGE FROM THE 60S IN THE NORTH TO
LOW 80S ACROSS THE SOUTH...WITH SOME AREAS ALREADY EXPERIENCING A
TEMPERATURE DROP.
THE LOW TO MID-LEVEL FRONTOGENESIS-FORCED BANDED RAIN EVENT FOR
TONIGHT STILL LOOKS PROBABLE. GENERALLY...MEASURABLE PRECIPITATION
APPEARS TO BE RELEGATED TO THE EASTERN THIRD OF THE COUNTY WARNING
AREA...EAST OF THE JAMES RIVER VALLEY. PRECIPITATION SHOULD BE
SHIFTING WELL EAST OF THE CWA BY 12Z MONDAY.
MODELS ARE INDICATING THAT PERHAPS A LITTLE BIT OF COLD AIR
INSTABILITY RAIN SHOWER POTENTIAL EXISTS ON MONDAY WITH COLD AIR
ALOFT AND STEEP LOW LEVEL LAPSE RATES POSSIBLE. NOT ALL THAT
CONFIDENT IN SHOWERS DEVELOPING ON MONDAY...SO LEFT WX GRIDS DRY
FOR NOW.
A TRANSIENT SURFACE HIGH PRESSURE SYSTEM IS PROGGED TO BE WORKING
THROUGH THE FORECAST AREA MONDAY NIGHT. UNLIKE SLOW-MOVING OR
STATIONARY SURFACE HIGHS...NOT A GOOD SET UP FOR TEMPERATURES
PLUMMETING INTO THE UPPER 20S FOR LOWS AS LIGHT WESTERLY SURFACE
WINDS DEVELOP BY OR AFTER 06Z TUESDAY. WHAT`S MORE...THE MODELS
ARE NO LONGER PROGGING CLEAR SKIES ALL NIGHT FOR MONDAY
NIGHT...BUT RATHER WITH A NORTH-NORTHWEST TO SOUTH-SOUTHEAST
ORIENTED MID/UPPER LEVEL BAROCLINIC ZONE IN PLACE OVER THE CWA AND
UPPER JET ENERGY WORKING THROUGH...MODELS ARE NOW GENERATING
MID-LEVEL CLOUDS ON THE INCREASE AFTER 06Z TUESDAY. SO...SEEMS
LIKE LOTS OF THINGS STARTING TO COME AGAINST SUB-FREEZING
TEMPERATURES MONDAY NIGHT. AS SUCH...HAVE ADJUSTED TEMPERATURES UP
A FEW DEGREES.
NO NOTEWORTHY CHANGES MADE TO TUESDAY OR TUESDAY NIGHT.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
THERE IS SOME MODEL DISAGREEMENT BETWEEN THE GFS/ECMWF WITH THE LONG
WAVE FLOW PATTERN ACROSS THE CONUS THROUGH THE LONG TERM PORTION OF
THE FORECAST. THE ISSUE BEGINS ON THURSDAY WITH THE ECMWF
RETROGRADING A LONG WAVE TROF TOWARD THE ROCKIES...WITH
SIGNIFICANTLY COLDER AIR FILTERING INTO THE CWA FOR THE WEEKEND.
THE ECMWF SUGGEST HIGH TEMPERATURES FOR THE WEEKEND WILL ONLY
CLIMB INTO THE 50S. SINCE THE ECMWF IS THE ONLY MODEL SUGGESTING
THE LONG WAVE TROF RETROGRADING...WILL IGNORE IT FOR THE TIME
BEING. THE GFS WAS ALSO IGNORED AS IT SEEMS TO PUSH THE TROF TOWARD
THE NEW ENGLAND STATES TOO QUICKLY. SIDED WITH THE MIDDLE OF THE
ROAD GFS ENSEMBLE MEAN WHICH SHOWS A GRADUAL WARMING TREND WITH
TEMPERATURES AROUND CLIMO FOR THE WEEKEND. GRANTED HIGHS IN THE UPPER 60S
TO THE LOWER 70S WILL SEEM COLD CONSIDER THE WARMER TEMPERATURES
WE HAVE HAD SO FAR THIS MONTH. THE GFS ENSEMBLE MEAN ALSO SUGGEST
DRY CONDITIONS WILL PREVAIL THROUGH THE PERIOD.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN UPPER LEVEL LOW PRESSURE TROUGH DROPPING THROUGH THE REGION
TONIGHT WILL BRING SOME AREAS OF LIGHT RAIN TO PARTS OF NORTHEAST
SD. THIS LIGHT RAIN MAY AFFECT AREAS IN AND AROUND MBG...ABR AND
ATY THROUGH THIS EVENING. OTHERWISE...VFR CONDITIONS ARE EXPECTED
FOR ALL TERMINALS THROUGH TONIGHT AND MONDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...DORN
LONG TERM...SD
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1117 PM CDT FRI SEP 14 2012
.DISCUSSION...
UPDATED FOR 06Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 828 PM CDT FRI SEP 14 2012/
UPDATE...
LATEST RADAR IMAGES SHOW A LARGE AREA OF RAIN OVER CENTRAL
ARKANSAS. MOST MODELS INDICATE THE RAIN SHOULD STAY WEST OF THE
CWA HOWEVER LOOKING AT KNQA RADAR THE FRONT EDGE OF THE RAIN CONTINUES
TO PUSH EAST. HRRR MODEL IS THE ONLY ONE THAT PUSHES THE RAIN INTO
THE CWA INCLUDING MEMPHIS BY 10-12Z. WILL UPDATE TO RAISE POPS
TO 50 ACROSS EASTERN ARKANSAS. WILL ALSO BUMP UP LOWS ACROSS THE
WEST DUE TO CLOUD COVER. UPDATE WILL BE OUT SHORTLY.
KRM
DISCUSSION... /ISSUED 305 PM CDT FRI SEP 14 2012/
SKIES ARE PARTLY TO MOSTLY CLOUDY ACROSS MUCH OF THE FORECAST
AREA THIS AFTERNOON WITH TEMPERATURES IN THE UPPER 70S TO UPPER
80S. THE COLD FRONT EXTENDS FROM NORTHWEST PENNSYLVANIA THROUGH
WEST TENNESSEE AND INTO SOUTHEAST TEXAS. SOME SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS CONTINUE TO MOVE ACROSS PORTIONS OF THE
FORECAST AREA NEAR THE FRONT. MOST OF THE ACTIVITY IN WEST
TENNESSEE IS MOVING SOUTHEAST WHILE THE ACTIVITY IN EAST ARKANSAS
IS MOVING NORTH.
AS THE FRONT CONTINUES TO PUSH EAST TONIGHT MORE SHOWERS AND A FEW
THUNDERSTORMS WILL BE POSSIBLE TONIGHT. THE FRONT SHOULD MOVE OUT
OF THE FORECAST AREA BY SATURDAY MORNING. HOWEVER AN UPPER LEVEL
DISTURBANCES WILL MOVE THROUGH THE REGION ON SATURDAY BRINGING
SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO WITH IT. AN
UPPER LEVEL TROUGH WILL MOVE THROUGH THE REGION SUNDAY AND MONDAY
BRINGING A BETTER CHANCE OF RAIN. TEMPERATURES THIS WEEKEND WILL
REMAIN AT OR A FEW DEGREES BELOW NORMAL FOR MID SEPTEMBER.
BY MONDAY NIGHT...A COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
BRINGING MORE SHOWERS AND A FEW THUNDERSTORMS. THIS FRONT SHOULD
BE OUT OF THE REGION BY TUESDAY MORNING WITH RAIN ENDING FROM WEST
TO EAST. MUCH COOLER AND DRIER AIR WILL MOVE INTO THE AREA BEHIND
THE FRONT WITH AFTERNOON TEMPERATURES ON TUESDAY IN THE 70S. SKIES
SHOULD CLEAR OUT AND WINDS WILL BECOME LIGHT BY WEDNESDAY MORNING
SETTING THE STAGE FOR A RATHER COOL MORNING. MANY LOCATIONS IN THE
NORTHERN HALF OF THE FORECAST AREA WILL SEE READINGS IN THE 40S ON
WEDNESDAY MORNING.
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER FROM WEDNESDAY
THROUGH EARLY FRIDAY MORNING WITH NO RAIN AND TEMPERATURES
REMAINING BELOW NORMAL. ANOTHER COLD FRONT WILL BE APPROACHING THE
REGION ON FRIDAY BRINGING A SMALL CHANCE OF SHOWERS AHEAD OF IT.
ARS
&&
.AVIATION...
06Z TAF CYCLE
MAINLY VFR CONDS WILL PREVAIL THROUGH THE PERIOD. SOME IFR/MVFR
CIGS MAY DEVELOP AT KJBR AND KMEM OVER THE NEXT FEW HOURS AND
HAVE ADDED SOME TEMPOS FOR THIS POSSIBILITY. SOME LIGHT FOG IS
ALSO POSSIBLE AT KMKL. CONDS SHOULD BE VFR EVERYWHERE AFT 15/13Z.
A FEW SHRAS WILL BE POSSIBLE NEAR KJBR AND KMEM THROUGH SATURDAY
THOUGH MOST PRECIP WILL REMAIN TO THE WEST. WINDS WILL GENERALLY
BE LIGHT NE.
SJM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 68 83 66 84 / 30 30 30 50
MKL 61 81 60 82 / 20 30 30 50
JBR 64 78 62 78 / 50 40 40 50
TUP 64 86 65 86 / 20 20 20 40
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1058 AM CDT SAT SEP 15 2012
.DISCUSSION...CONVECTION HAS REMAINED OVER THE GULF WATERS NEAR
THE FRONTAL BOUNDARY LOCATED OVER THE NEARSHORE WATERS. THE BOUNDARY
IS EXPECTED TO DRIFT INLAND BY THIS AFTERNOON AS WINDS OFFSHORE
HAVE SHIFTED TO THE EAST. EXPECT THE FRONT WILL REMAIN A FOCUS FOR
CONVECTIVE DEVELOPMENT. 12Z CRP SOUNDING SHOWED PLENTIFUL MOISTURE
WITH PRECIPITABLE WATER AT 2.14 INCHES. ONCE FRONTAL INVERSION IS
REMOVED WITH A LITTLE BIT OF HEATING...EXPECT CONVECTION WILL FORM
DURING THE AFTERNOON OVER THE COASTAL PLAINS. THE 00Z 4KM WRF MODEL
GIVES A BIT OF CONFIDENCE IN THIS SCENARIO. WILL HAVE TO WAIT UNTIL
TONIGHT FOR UPPER DYNAMICS TO APPROACH FOR BETTER RAIN CHANCES OUT
WEST. WOULD PREFER TO SEE BETTER LOW LEVEL THERMAL ADVECTION
PROFILE FOR LIKELY POPS BUT ENERGETIC UPPER LEVEL JET STREAK
COMING OUT OF NORTHERN MEXICO INTO CENTRAL TEXAS SHOULD PROVIDE
SUFFICIENT LIFT TO WARRANT THE HIGH POPS NORTHWEST FOR LATER
TONIGHT. LOWERED MAX TEMPS A CATEGORY FOR NORTHERN BRUSH COUNTRY
TODAY.
&&
.PREV DISCUSSION... /ISSUED 639 AM CDT SAT SEP 15 2012/
DISCUSSION...UPDATE FOR 12Z AVIATION BELOW.
AVIATION...COLD FRONT HAS BECOME STATIONARY JUST OFFSHORE EARLY
THIS MORNING WITH N TO NE WINDS AROUND 10 KTS PREVAILING BEHIND IT
ACROSS SOUTH TEXAS TERMINALS. BKN MVFR CIGS WILL PREVAIL THROUGH
THE MORNING AT MANY TAF SITES. IN ADDITION...ISOLATED SHRA
POSSIBLE DURING THE MORNING NEAR VCT. NUMEROUS SHOWERS AND
THUNDERSTORMS LOCATED NEAR THE FRONT SHOULD REMAIN JUST OFFSHORE
THROUGH THE MORNING. THE FRONT WILL WEAKEN AND WASH OUT IN THE
AFTERNOON. AS THIS HAPPENS...CIGS WILL BECOME VFR ACROSS SOUTH
TEXAS TERMINALS AND ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP INLAND.
PREV DISCUSSION... /ISSUED 357 AM CDT SAT SEP 15 2012/
SHORT TERM (TODAY THROUGH SUNDAY)...MSAS ANALYSIS REVEALS FRONTAL
HAS BECOME STATIONARY EARLY THIS MORNING ACROSS THE NEARSHORE
MIDDLE TEXAS COASTAL WATERS. WEAK MID/UPPER LEVEL CYCLONIC SHEAR
AXIS ALSO OVER THE REGION...AND THE TWO FEATURES ARE INTERACTING
WITH DEEP MOISTURE AND GENERATING NUMEROUS SHOWERS AND THUNDERSTORMS
JUST OFFSHORE. GFS/NAM IN ADDITION TO HRRR AND NSSL 4 KM WRF
INDICATE THE BOUNDARY REMAINING JUST OFFSHORE THROUGH THE MORNING
HOURS...ALTHOUGH A SLIGHT WESTWARD DRIFT IN THE CONVECTION IS
LIKELY TO OCCUR. SOME OF THESE SHOWERS AND THUNDERSTORMS MAY
SNEAK ACROSS THE BARRIER ISLANDS INTO COASTAL LOCATIONS OF NUECES
AND KLEBERG COUNTIES THROUGH THE MORNING...BUT THE BULK OF THE
CONVECTION WILL REMAIN JUST OFFSHORE. FURTHER INLAND ACROSS SOUTH
TEXAS...A FEW WEAK SHOWERS MAY DEVELOP TOWARDS AND AFTER SUNRISE.
A SHARP GRADIENT IN POPS IS INDICATED THIS MORNING. LATER THIS
AFTERNOON...THE BOUNDARY DRIFTS BACK INLAND AND WASHES OUT. A
RETURN TO WEAK ONSHORE FLOW SHOULD ALLOW FOR ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS THE INLAND COASTAL
BEND AND BRUSH COUNTRY MID TO LATE AFTERNOON.
ATTENTION THEN SHIFTS TO LATE TONIGHT INTO SUNDAY. POSITIVELY
TILTED TROUGH APPROACHES THE RIO GRANDE PLAINS AFTER MIDNIGHT
ALONG WITH A MODEST 50-60 KT UPPER LEVEL JET STREAK. MID/UPPER
LEVEL FORCING WILL GRADUALLY INCREASE OVERNIGHT AND PEAK ACROSS
THE RIO GRANDE PLAINS AND WESTERN BRUSH COUNTRY AROUND 12Z SUNDAY.
THE FORCING GRADUALLY MOVES EASTWARD DURING THE SUNDAY...INTO THE
COASTAL BEND/VICTORIA REGION MIDDAY. SHOWERS AND THUNDERSTORMS ARE
LIKELY ACROSS WESTERN CWA OVERNIGHT AND EARLY SUNDAY MORNING...AND
ACROSS THE EAST LATE SUNDAY MORNING THROUGH AFTERNOON. POPS ARE
HIGHEST ACROSS THE NORTH AND NORTHEAST CWA SUNDAY. HIGH TEMPS VERY
DEPENDENT ON CLOUD COVER AND RAINFALL TODAY AND SUNDAY...GENERALLY
IN THE MID AND UPPER 80S.
LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)...MID LVL TROUGH WILL
ADVANCE INTO THE COASTAL WATERS SUN NIGHT WITH PCPN ENDING OVER THE
WATERS BY MONDAY MORNING. CLEARING SKIES AND SUBSIDENT FLOW WILL
ALLOW TEMPS TO RECOVER INTO THE 90S AREA WIDE. ANOTHER TROUGH AND
ASSOCIATED WEAK COOL FRONT WILL DIP INTO SOUTH TEXAS TUESDAY.
HOWEVER NOT EXPECTING PCPN DUE TO DRY ATMOSPHIC COLUMN (PWS NEAR
1.3"). ENOUGH MOISTURE WILL POOL ALONG THE BOUNDARY OVER THE GULF
WATERS BY WED AM TO GENERATE A FEW SHOWERS. A WEAK MID LVL RIDGE
WILL BUILD BACK OVER SOUTH TEXAS THROUGH THE REMAINDER OF THE WEEK
WITH A GRADUAL WARMING TREND AND NO SIGNIFICANT OPPORTUNITIES FOR
RAINFALL. A WEAK TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH THE
END OF THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 89 71 87 70 90 / 50 40 70 20 10
VICTORIA 88 68 86 67 90 / 50 50 80 30 10
LAREDO 88 70 88 71 98 / 40 60 50 10 10
ALICE 89 69 87 68 93 / 50 40 70 20 10
ROCKPORT 86 71 85 71 89 / 50 40 80 30 10
COTULLA 84 67 85 68 94 / 40 70 70 10 10
KINGSVILLE 88 70 87 69 91 / 50 40 70 20 10
NAVY CORPUS 86 73 86 73 87 / 50 40 70 20 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TT/89...SHORT TERM
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
639 AM CDT SAT SEP 15 2012
.DISCUSSION...UPDATE FOR 12Z AVIATION BELOW.
&&
.AVIATION...COLD FRONT HAS BECOME STATIONARY JUST OFFSHORE EARLY
THIS MORNING WITH N TO NE WINDS AROUND 10 KTS PREVAILING BEHIND IT
ACROSS SOUTH TEXAS TERMINALS. BKN MVFR CIGS WILL PREVAIL THROUGH
THE MORNING AT MANY TAF SITES. IN ADDITION...ISOLATED SHRA
POSSIBLE DURING THE MORNING NEAR VCT. NUMEROUS SHOWERS AND
THUNDERSTORMS LOCATED NEAR THE FRONT SHOULD REMAIN JUST OFFSHORE
THROUGH THE MORNING. THE FRONT WILL WEAKEN AND WASH OUT IN THE
AFTERNOON. AS THIS HAPPENS...CIGS WILL BECOME VFR ACROSS SOUTH
TEXAS TERMINALS AND ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP INLAND.
&&
.PREV DISCUSSION... /ISSUED 357 AM CDT SAT SEP 15 2012/
SHORT TERM (TODAY THROUGH SUNDAY)...MSAS ANALYSIS REVEALS FRONTAL
HAS BECOME STATIONARY EARLY THIS MORNING ACROSS THE NEARSHORE
MIDDLE TEXAS COASTAL WATERS. WEAK MID/UPPER LEVEL CYCLONIC SHEAR
AXIS ALSO OVER THE REGION...AND THE TWO FEATURES ARE INTERACTING
WITH DEEP MOISTURE AND GENERATING NUMEROUS SHOWERS AND THUNDERSTORMS
JUST OFFSHORE. GFS/NAM IN ADDITION TO HRRR AND NSSL 4 KM WRF
INDICATE THE BOUNDARY REMAINING JUST OFFSHORE THROUGH THE MORNING
HOURS...ALTHOUGH A SLIGHT WESTWARD DRIFT IN THE CONVECTION IS
LIKELY TO OCCUR. SOME OF THESE SHOWERS AND THUNDERSTORMS MAY
SNEAK ACROSS THE BARRIER ISLANDS INTO COASTAL LOCATIONS OF NUECES
AND KLEBERG COUNTIES THROUGH THE MORNING...BUT THE BULK OF THE
CONVECTION WILL REMAIN JUST OFFSHORE. FURTHER INLAND ACROSS SOUTH
TEXAS...A FEW WEAK SHOWERS MAY DEVELOP TOWARDS AND AFTER SUNRISE.
A SHARP GRADIENT IN POPS IS INDICATED THIS MORNING. LATER THIS
AFTERNOON...THE BOUNDARY DRIFTS BACK INLAND AND WASHES OUT. A
RETURN TO WEAK ONSHORE FLOW SHOULD ALLOW FOR ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS THE INLAND COASTAL
BEND AND BRUSH COUNTRY MID TO LATE AFTERNOON.
ATTENTION THEN SHIFTS TO LATE TONIGHT INTO SUNDAY. POSITIVELY
TILTED TROUGH APPROACHES THE RIO GRANDE PLAINS AFTER MIDNIGHT
ALONG WITH A MODEST 50-60 KT UPPER LEVEL JET STREAK. MID/UPPER
LEVEL FORCING WILL GRADUALLY INCREASE OVERNIGHT AND PEAK ACROSS
THE RIO GRANDE PLAINS AND WESTERN BRUSH COUNTRY AROUND 12Z SUNDAY.
THE FORCING GRADUALLY MOVES EASTWARD DURING THE SUNDAY...INTO THE
COASTAL BEND/VICTORIA REGION MIDDAY. SHOWERS AND THUNDERSTORMS ARE
LIKELY ACROSS WESTERN CWA OVERNIGHT AND EARLY SUNDAY MORNING...AND
ACROSS THE EAST LATE SUNDAY MORNING THROUGH AFTERNOON. POPS ARE
HIGHEST ACROSS THE NORTH AND NORTHEAST CWA SUNDAY. HIGH TEMPS VERY
DEPENDENT ON CLOUD COVER AND RAINFALL TODAY AND SUNDAY...GENERALLY
IN THE MID AND UPPER 80S.
LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)...MID LVL TROUGH WILL
ADVANCE INTO THE COASTAL WATERS SUN NIGHT WITH PCPN ENDING OVER THE
WATERS BY MONDAY MORNING. CLEARING SKIES AND SUBSIDENT FLOW WILL
ALLOW TEMPS TO RECOVER INTO THE 90S AREA WIDE. ANOTHER TROUGH AND
ASSOCIATED WEAK COOL FRONT WILL DIP INTO SOUTH TEXAS TUESDAY.
HOWEVER NOT EXPECTING PCPN DUE TO DRY ATMOSPHIC COLUMN (PWS NEAR
1.3"). ENOUGH MOISTURE WILL POOL ALONG THE BOUNDARY OVER THE GULF
WATERS BY WED AM TO GENERATE A FEW SHOWERS. A WEAK MID LVL RIDGE
WILL BUILD BACK OVER SOUTH TEXAS THROUGH THE REMAINDER OF THE WEEK
WITH A GRADUAL WARMING TREND AND NO SIGNIFICANT OPPORTUNITIES FOR
RAINFALL. A WEAK TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH THE
END OF THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 71 87 70 90 71 / 40 70 20 10 10
VICTORIA 68 86 67 90 67 / 50 80 30 10 10
LAREDO 70 88 71 98 73 / 60 50 10 10 10
ALICE 69 87 68 93 69 / 40 70 20 10 10
ROCKPORT 71 85 71 89 73 / 40 80 30 10 10
COTULLA 67 85 68 94 69 / 70 70 10 10 10
KINGSVILLE 70 87 69 91 70 / 40 70 20 10 10
NAVY CORPUS 73 86 73 87 75 / 40 70 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
JR/76...SHORT TERM/AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
357 AM CDT SAT SEP 15 2012
.SHORT TERM (TODAY THROUGH SUNDAY)...MSAS ANALYSIS REVEALS FRONTAL
HAS BECOME STATIONARY EARLY THIS MORNING ACROSS THE NEARSHORE
MIDDLE TEXAS COASTAL WATERS. WEAK MID/UPPER LEVEL CYCLONIC SHEAR
AXIS ALSO OVER THE REGION...AND THE TWO FEATURES ARE INTERACTING
WITH DEEP MOISTURE AND GENERATING NUMEROUS SHOWERS AND THUNDERSTORMS
JUST OFFSHORE. GFS/NAM IN ADDITION TO HRRR AND NSSL 4 KM WRF
INDICATE THE BOUNDARY REMAINING JUST OFFSHORE THROUGH THE MORNING
HOURS...ALTHOUGH A SLIGHT WESTWARD DRIFT IN THE CONVECTION IS
LIKELY TO OCCUR. SOME OF THESE SHOWERS AND THUNDERSTORMS MAY
SNEAK ACROSS THE BARRIER ISLANDS INTO COASTAL LOCATIONS OF NUECES
AND KLEBERG COUNTIES THROUGH THE MORNING...BUT THE BULK OF THE
CONVECTION WILL REMAIN JUST OFFSHORE. FURTHER INLAND ACROSS SOUTH
TEXAS...A FEW WEAK SHOWERS MAY DEVELOP TOWARDS AND AFTER SUNRISE.
A SHARP GRADIENT IN POPS IS INDICATED THIS MORNING. LATER THIS
AFTERNOON...THE BOUNDARY DRIFTS BACK INLAND AND WASHES OUT. A
RETURN TO WEAK ONSHORE FLOW SHOULD ALLOW FOR ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS THE INLAND COASTAL
BEND AND BRUSH COUNTRY MID TO LATE AFTERNOON.
ATTENTION THEN SHIFTS TO LATE TONIGHT INTO SUNDAY. POSITIVELY
TILTED TROUGH APPROACHES THE RIO GRANDE PLAINS AFTER MIDNIGHT
ALONG WITH A MODEST 50-60 KT UPPER LEVEL JET STREAK. MID/UPPER
LEVEL FORCING WILL GRADUALLY INCREASE OVERNIGHT AND PEAK ACROSS
THE RIO GRANDE PLAINS AND WESTERN BRUSH COUNTRY AROUND 12Z SUNDAY.
THE FORCING GRADUALLY MOVES EASTWARD DURING THE SUNDAY...INTO THE
COASTAL BEND/VICTORIA REGION MIDDAY. SHOWERS AND THUNDERSTORMS ARE
LIKELY ACROSS WESTERN CWA OVERNIGHT AND EARLY SUNDAY MORNING...AND
ACROSS THE EAST LATE SUNDAY MORNING THROUGH AFTERNOON. POPS ARE
HIGHEST ACROSS THE NORTH AND NORTHEAST CWA SUNDAY. HIGH TEMPS VERY
DEPENDENT ON CLOUD COVER AND RAINFALL TODAY AND SUNDAY...GENERALLY
IN THE MID AND UPPER 80S.
&&
.LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)...MID LVL TROUGH WILL
ADVANCE INTO THE COASTAL WATERS SUN NIGHT WITH PCPN ENDING OVER THE
WATERS BY MONDAY MORNING. CLEARING SKIES AND SUBSIDENT FLOW WILL
ALLOW TEMPS TO RECOVER INTO THE 90S AREA WIDE. ANOTHER TROUGH AND
ASSOCIATED WEAK COOL FRONT WILL DIP INTO SOUTH TEXAS TUESDAY.
HOWEVER NOT EXPECTING PCPN DUE TO DRY ATMOSPHIC COLUMN (PWS NEAR
1.3"). ENOUGH MOISTURE WILL POOL ALONG THE BOUNDARY OVER THE GULF
WATERS BY WED AM TO GENERATE A FEW SHOWERS. A WEAK MID LVL RIDGE
WILL BUILD BACK OVER SOUTH TEXAS THROUGH THE REMAINDER OF THE WEEK
WITH A GRADUAL WARMING TREND AND NO SIGNIFICANT OPPORTUNITIES FOR
RAINFALL. A WEAK TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH THE
END OF THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 89 71 87 70 90 / 50 40 70 20 10
VICTORIA 88 68 86 67 90 / 50 50 80 30 10
LAREDO 88 70 88 71 98 / 40 60 50 10 10
ALICE 89 69 87 68 93 / 50 40 70 20 10
ROCKPORT 86 71 85 71 89 / 50 40 80 30 10
COTULLA 86 67 85 68 94 / 40 70 70 10 10
KINGSVILLE 88 70 87 69 91 / 50 40 70 20 10
NAVY CORPUS 86 73 86 73 87 / 50 40 70 20 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
JR/76...SHORT TERM
JM/75...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
305 AM CDT SAT SEP 15 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
305 AM CDT SAT SEP 15 2012
MAIN FORECAST CONCERN REMAINS ON THE SUNDAY NIGHT THROUGH MONDAY
NIGHT TIME FRAME WITH TIMING OF THE PRECIPITATION AND TEMPERATURES
IN ITS WAKE.
07Z SURFACE ANALYSIS SHOWS HIGH PRESSURE FROM LAKE SUPERIOR THROUGH
EASTERN WISCONSIN AND ILLINOIS. SKIES WERE CLEAR AROUND THE FORECAST
AREA WITH JUST SOME PATCHY FOG IN SOME OF THE FOG PRONE AREAS OF
CENTRAL WISCONSIN.
15.00Z MODELS IN EXCELLENT AGREEMENT THROUGH THE PERIOD...WITH THE
MAIN CHANGE BEING A SLOWER ONSET OF PRECIPITATION ACROSS THE AREA
SUNDAY NIGHT. OTHERWISE PREVIOUS FORECAST ON TRACK.
IN THE NEAR TERM...HIGH PRESSURE WILL CONTINUE TO SLIDE EAST OF THE
AREA TODAY...WITH PRESSURE GRADIENT TIGHTENING. TEMPERATURES WILL BE
A FEW DEGREES WARMER THAN YESTERDAY WITH PERSISTENT SOUTHWEST FLOW.
WITH GOOD MIXING AND WINDS GUSTING TO NEAR 20 MPH WILL SEE NEAR
CRITICAL FIRE WEATHER CONDITIONS ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA (SEE FIRE WEATHER DISCUSSION BELOW). THIS QUIET
WEATHER WILL CONTINUE RIGHT INTO SUNDAY...WITH THE WARM TEMPERATURES
CONTINUING UNDER PLENTY OF SUNSHINE.
ATTENTION THEN TURNS TO THE SUNDAY NIGHT THROUGH MONDAY NIGHT TIME
FRAME. SHORTWAVE TROUGH DIGS ACROSS THE NORTHERN PLAINS...PUSHING
SURFACE COLD FRONT ACROSS THE AREA ON MONDAY. RATHER STRONG
850MB-700MB FRONTOGENESIS ACCOMPANIES THE FRONT ACROSS THE AREA.
MODELS HAVE TRENDED SLOWER WITH THE SYSTEM AND THUS HAVE BACKED OFF
ON RAIN PROBABILITIES SUNDAY EVENING. BOTH THE GFS AND NAM SHOWING
500-1000 J/KG OF MOST UNSTABLE CAPE SUNDAY NIGHT AND MONDAY AND THUS
DID KEEP THE ISOLATED THUNDER MENTION IN THE GRIDS. SEVERE WEATHER
POTENTIAL LOOKS TO BE RATHER LIMITED AS SHEAR ONLY 25 TO 30
KNOTS...BUT CANNOT RULE OUT SOME SMALL HAIL OR GUSTY WINDS WITH SOME
OF THE STRONGER CELLS. HIGHEST RAIN PROBABILITIES LOOK TO BE LATE
SUNDAY NIGHT INTO MONDAY. STRONG COLD ADVECTION IN THE WAKE OF THE
FRONT...COMBINED WITH THE CLOUDS AND RAIN WILL HOLD TEMPERATURES
DOWN ON MONDAY...WITH HIGHS MAINLY IN THE 60S.
AS THE FRONT PULLS EAST OF THE AREA MONDAY NIGHT...HIGH PRESSURE
SETTLES IN FROM THE WEST. MODELS DO SHOW A DECREASE IN THE
CLOUDS...WITH STILL STRONG COLD AIR ADVECTION. TEMPERATURES EXPECTED
TO DROP INTO THE 30S IN MANY LOCATIONS. HOWEVER...MODELS ARE SHOWING
PRESSURE GRADIENT TO REMAIN STRONG ENOUGH TO PRECLUDE THE MENTION
OF FROST...BUT THIS WILL HAVE TO BE WATCHED.
.LONG TERM...TUESDAY THROUGH FRIDAY
305 AM CDT SAT SEP 15 2012
A COOL PERIOD IS IN STORE FOR THE REGION THROUGH THE PERIOD AS THE
PATTERN WILL BE DOMINATED BY NORTHWEST FLOW ALOFT. HIGHS MAY
STRUGGLE TO GET OUT OF THE 50S ON TUESDAY...DESPITE PLENTY OF
SUNSHINE. ANOTHER SHORTWAVE DROPS THROUGH THE FLOW ON WEDNESDAY
PUSHING YET ANOTHER SURFACE BOUNDARY ACROSS THE AREA. SOME SHOWERS
ARE POSSIBLE WITH THE FRONTAL PASSAGE. AS WAVES CONTINUE TO RIDE
THROUGH THE FLOW THURSDAY AND FRIDAY...A LONG WAVE TROUGH DEVELOPS
OVER THE UPPER MIDWEST BY THE END OF THE WEEK. THE ECMWF DOES
DEVELOP A CLOSED 500MB LOW OVER WISCONSIN BY 18Z FRIDAY...WHILE THE
GFS CLOSES THE LOW OFF FURTHER NORTH OVER SOUTHERN ONTARIO. NONE
THE LESS...THE COOL WEATHER WILL CONTINUE WITH A CHANCE OF SHOWERS
OVER PORTIONS OF THE AREA.
&&
.AVIATION...THROUGH 06Z SUNDAY
1149 PM CDT FRI SEP 14 2012
AS EXPECTED...THE DEW POINT RECOVERED BACK INTO THE MID 40S THIS
EVENING...BUT THE TEMP/DEW POINT SPREAD WAS 10 DEGREES AT BOTH 03Z
AND 04Z. WHILE DENSE VALLEY FOG IS STILL POSSIBLE WITH THIS
TEMP/DEW POINT SPREAD IT IS NOT VERY PROBABLE. ALSO...THE WINDS AT
THE SURFACE HAVE ALREADY SWUNG AROUND TO THE SOUTHEAST AND THE
15.00Z NAM AND 15.01Z RAP BUFKIT SOUNDING INDICATE THIS WILL
CONTINUE THROUGH THE NIGHT. THE WINDS AT THE RIDGE TOP LEVEL ARE
EXPECTED TO COME AROUND THE SOUTH/SOUTHWEST OVERNIGHT AND INCREASE
TO A RANGE OF 15 TO 20 KNOTS WHICH WOULD ALSO HELP PREVENT THE FOG
FORMATION. THIS TURNING OF THE WINDS LOOKS TO BE LEGITIMATE AS THE
VWP FROM KMPX SHOWS A TURN TO THE SOUTHWEST HAS OCCURRED THERE.
WILL THUS BACK OUT OF THE FOG SCENARIO FOR KLSE AND GO WITH VFR
CONDITIONS THROUGH THE NIGHT BUT CONTINUE TO INCLUDE BCFG IN THE
EVENT THE WINDS DO NOT COME UP AS EXPECTED. AS THE HIGH CONTINUES
TO PULL AWAY...THE GRADIENT AHEAD OF THE NEXT APPROACHING SYSTEM
WILL INCREASE ENOUGH TO PRODUCE SOME GUSTS AROUND 20 KNOTS
SATURDAY AFTERNOON AT KRST.
&&
.FIRE WEATHER...THIS AFTERNOON
305 PM CDT SAT SEP 15 2012
NEAR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED OVER SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON. AS THE HIGH TRANSLATES
EASTWARD...THE PRESSURE GRADIENT WILL TIGHTEN WITH SOUTHERLY WINDS
GUSTING TO 20-22 MPH. DEW POINTS SHOULD AGAIN LOWER IN THE AFTERNOON
PROVIDING DRY RELATIVE HUMIDITIES IN THE MIDDLE 20S. AT THIS TIME
THE CONDITIONS WILL IMPACT FIRE CONTROL BUT A RED FLAG WARNING WILL
NOT BE NEEDED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 AM CDT SAT SEP 15 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
FIRE WEATHER...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 PM CDT FRI SEP 14 2012
.SHORT TERM...THROUGH MONDAY
325 PM CDT FRI SEP 14 2012
MOST OF THE FORECAST SHIFT WAS SPENT ON EARLY NEXT WEEK AS A
POTENT COLD FRONT MOVES THROUGH. THERE IS SOME CHANCE FOR RIVER
VALLEY FOG SATURDAY MORNING AS WELL. OVERALL THE ONGOING FORECAST
WAS IN GOOD SHAPE AND SMALL CHANGES WERE MADE.
LARGE HEIGHT RISES SEEN TO THE NORTHWEST IN THE MORNING RAOBS
WITH 130M/12HR AT KINL AT 250 MB INDICATIVE OF THE RIDGE BUILDING
TAKING PLACE INTO THE GREAT LAKES FOR THE WEEKEND. THIS RISE IS
LARGE IN EXPANSE AS WELL...ALMOST NORTH TO THE NW TERRITORIES OF
CANADA. LARGEST FALLS HAVE JUST COME INTO BRITISH COLUMBIA THIS
MORNING AND THIS WILL BE THE WEATHER SYSTEM THAT AFFECTS THE AREA
MONDAY. AN UNUSUALLY DRY AIR MASS IS MOVING IN AS WELL WITH 50
PERCENT NORMAL PRECIPITABLE WATER OVER THE ENTIRE NORTHERN PLAINS JUST
NW OF THE AREA.
MODELS IN REMARKABLE AGREEMENT THROUGH THE SHORT TERM WITH ONLY
MINOR TIMING DIFFERENCES NOTED WITH THE FRONT ON MONDAY. THE
PREDICTABILITY SEEMS HIGHER THAN NORMAL.
TONIGHT IS AGAIN A TOUGH VALLEY FOG FORECAST. THE WIND SPEEDS ARE
SINGLE DIGITS IN THE LOWEST 1KM...CLEAR SKIES AND DRY CONDITIONS
ALOFT ALSO ARE EXCELLENT. DEW POINTS HAVE NOT LOWERED TOO MUCH
TODAY AND THIS IS ALSO FAVORABLE...AND THE ONE LIMITING FACTOR WE
HAVE BEEN WATCHING CLOSELY. THERE HAVE BEEN NO DENSE VALLEY FOG
DAYS IN SEPTEMBER WHERE THE 00Z T/TD SPREAD WAS OVER 23F. WE ARE
THINKING IT WILL BE ABOUT 20F AT 00Z. SO...PROBABILITIES SEEM TO
BE INCREASING FOR SATURDAY MORNING VALLEY FOG...LOCALLY
DENSE...AND HAVE STEPPED UP THE COVERAGE IN THE FORECAST.
HAVE TAKEN A STEP TO BUILD SOME TIMING INTO THE PRECIPITATION
SUNDAY NIGHT AND MONDAY. THE 14.12Z MODEL AGREEMENT ON THE RAIN
BAND MOVING IN ASSOCIATED WITH THE CURRENT BRITISH COLUMBIA
SHORTWAVE TROUGH IS VERY GOOD. THERE WAS A SLIGHT INCREASE IN
SPEED AND WHILE SUNDAY REMAINS DRY...IT APPEARS THE AREA IS GOING
TO SEE RAIN SUNDAY NIGHT AND MONDAY. THE STRONG SHORTWAVE TROUGH
WILL HAVE MANY FORCING MECHANISMS FOR LIFT INCLUDING 700-850 MB
FRONTOGENESIS AND UPPER LEVEL JET ENTRANCE REGION DIVERGENCE.
MOISTURE FROM THE SOUTH WILL INCREASE SUNDAY INTO THE
FRONT...INCREASING THE EASE IN PRODUCING RAIN. THE 14.09Z AND
14.15Z SREF REMAIN FAST WITH THE HIGHEST RAIN PROBABILITIES OVER
THE FORECAST AREA SUNDAY NIGHT...AND THUS FELT IT WAS PRUDENT TO
INCREASE THE RAIN CHANCES FOR SW WI BY MONDAY MORNING. BOTTOM
LINE IS THAT TIMING IS STILL SOMEWHAT SHAKY...BUT ALL AREAS WILL
LIKELY SEE RAIN FROM THIS SYSTEM.
SOME INSTABILITY WILL BUILD IN THE WARM SECTOR PRE-FRONTALLY ON
SUNDAY AND ENHANCE THE RAIN CHANCES SUNDAY NIGHT. A GOOD CAPPING
INVERSION REMAINS IN THE PLACE TO LIMIT CONVECTION ON AND AHEAD
OF THE FRONT. SO...DO NOT FEEL SEVERE CHANCES ARE TOO GREAT WITH
WEAKER SHEAR AND SBCAPES IN THE 500 J/KG RANGE. EMBEDDED POST-
FRONTAL THUNDER IS POSSIBLE...BUT NOT A LARGE CONCERN.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
325 PM CDT FRI SEP 14 2012
THIS PERIOD IS DOMINATED BY THE LARGE SCALE TROUGH AND BELOW
NORMAL TEMPERATURES. 850 MB TEMPERATURE ANOMALIES ARE IN THE
2-2.5 RANGE WHICH IS APPROACHING RECORD COLD. CHECKING THE RECORD
LOWS AND LOW MAX TEMPERATURES...WE ARE A HANDFUL OF DEGREES AWAY
NEXT WEEK. WITH THE PROGRESSIVE NORTHWEST FLOW...IDEAL RADIATIVE
COOLING NIGHTS LOOK MINIMAL RIGHT NOW TO TARGET A DAY FOR RECORD
COLD. BUT...PEOPLE WILL NOTICE THIS COLD.
OVERALL WITH THE BAROCLINIC ZONE NEARBY...EACH NW FLOW SHORT WAVE
TROUGH WILL WORK ON THE RIBBON AND THIS DOES CAUSE SOME MODEL
DIFFERENCES. ON TUESDAY...THE 14.12Z GFS IS AN OUTLIER WITH THE
WARMING FROM THE WEST...SUGGESTING HIGHS IN THE MIDDLE 60S.
14.12Z CANADIAN/ECMWF AND 14.00Z ECMWF ARE MUCH SLOWER WITH THE
WARMING AND AFTER A COLD MORNING...HAVE DECIDED TO KEEP HIGHS
ABOUT 5F LOWER THAN GFS SUGGESTIONS. OVERALL WE WILL HAVE
PROGRESSIVE PRECIPITATION CHANCES AND A COLD PERIOD.
&&
.AVIATION...THROUGH 06Z SUNDAY
1149 PM CDT FRI SEP 14 2012
AS EXPECTED...THE DEW POINT RECOVERED BACK INTO THE MID 40S THIS
EVENING...BUT THE TEMP/DEW POINT SPREAD WAS 10 DEGREES AT BOTH 03Z
AND 04Z. WHILE DENSE VALLEY FOG IS STILL POSSIBLE WITH THIS
TEMP/DEW POINT SPREAD IT IS NOT VERY PROBABLE. ALSO...THE WINDS AT
THE SURFACE HAVE ALREADY SWUNG AROUND TO THE SOUTHEAST AND THE
15.00Z NAM AND 15.01Z RAP BUFKIT SOUNDING INDICATE THIS WILL
CONTINUE THROUGH THE NIGHT. THE WINDS AT THE RIDGE TOP LEVEL ARE
EXPECTED TO COME AROUND THE SOUTH/SOUTHWEST OVERNIGHT AND INCREASE
TO A RANGE OF 15 TO 20 KNOTS WHICH WOULD ALSO HELP PREVENT THE FOG
FORMATION. THIS TURNING OF THE WINDS LOOKS TO BE LEGITIMATE AS THE
VWP FROM KMPX SHOWS A TURN TO THE SOUTHWEST HAS OCCURRED THERE.
WILL THUS BACK OUT OF THE FOG SCENARIO FOR KLSE AND GO WITH VFR
CONDITIONS THROUGH THE NIGHT BUT CONTINUE TO INCLUDE BCFG IN THE
EVENT THE WINDS DO NOT COME UP AS EXPECTED. AS THE HIGH CONTINUES
TO PULL AWAY...THE GRADIENT AHEAD OF THE NEXT APPROACHING SYSTEM
WILL INCREASE ENOUGH TO PRODUCE SOME GUSTS AROUND 20 KNOTS
SATURDAY AFTERNOON AT KRST.
&&
.FIRE WEATHER...
325 PM CDT FRI SEP 14 2012
NEAR CRITICAL FIRE WEATHER CONDITIONS ARE STILL EXPECTED OVER
SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON SATURDAY. AS THE HIGH
TRANSLATES EASTWARD...THE PRESSURE GRADIENT WILL TIGHTEN WITH
SOUTHERLY WINDS GUSTING TO 20-22 MPH. DEW POINTS SHOULD AGAIN
LOWER IN THE AFTERNOON PROVIDING DRY RELATIVE HUMIDITIES IN THE
MIDDLE 20S. AT THIS TIME THE CONDITIONS WILL IMPACT FIRE CONTROL
BUT A RED FLAG WARNING IS NOT ANTICIPATED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
325 PM CDT FRI SEP 14 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...04
FIRE WEATHER...RIECK
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1205 AM CDT MON SEP 17 2012
.UPDATE...
ISSUED 1205 AM CDT MON SEP 17 2012
REVISED AVIATION DISCUSSION FOR 06Z TAFS.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED 308 PM CDT SUN SEP 16 2012
THE WEAK SYSTEM RESPONSIBLE FOR THE SHOWERS LAST NIGHT AND EARLY
THIS MORNING DISSIPATED AS IT MOVED EAST TODAY. IN ITS WAKE...SOME
PARTIAL CLEARING DEVELOPED ACROSS THE LOWER OHIO VALLEY. WITH THE
SOLAR HEATING...A FEW ISOLATED SHOWERS POPPED UP NEAR KPOF THIS
AFTERNOON.
OF MORE SIGNIFICANCE IS A LARGER AREA OF SHOWERS AND EVEN A FEW
THUNDERSTORMS ALONG AND SOUTH OF INTERSTATE 40 AS OF 19Z. THE
MAJORITY OF THE MODELS BRING THIS AREA NORTHWARD INTO SE MISSOURI
AND SW KENTUCKY TONIGHT...AND EVENTUALLY UP INTO THE EVV AREA
SOMETIME LATE TONIGHT OR MONDAY MORNING. THE PRIMARY EXCEPTION IS
THE SREF...WHICH TENDS TO SUPPRESS THE SOUTHERN STREAM SHORTWAVE
AND ITS ASSOCIATED QPF TO OUR SOUTH. THE 15Z RUC MODEL WAS RATHER
AGGRESSIVE BRINGING MOISTURE NORTH FROM ARKANSAS...AND THIS WILL
BE THE BASIS FOR THROWING OUT THE SREF.
THE RATHER STRONG 500 MB SHORTWAVE OVER TEXAS WILL MOVE EAST
NORTHEAST TONIGHT...BACKING OUR MID LEVEL WINDS INTO THE
SOUTHWEST. THIS WILL OPEN THE DOOR FOR A SERIES OF VORT CENTERS
THAT WILL MOVE NORTHEAST INTO THE OHIO VALLEY OVERNIGHT AND
MONDAY. DEEP LAYER SOUTHERLY FLOW WILL BRING A SURGE OF HIGHER PW
AIR NORTHWARD...WITH PW VALUES CLIMBING ABOVE 1.5 INCHES BY
MONDAY. POPS WILL RISE INTO THE LIKELY CATEGORY OVERNIGHT ACROSS
FAR SOUTHERN PORTIONS OF THE FA...WITH CHANCE POPS ELSEWHERE.
LIKELY POPS WILL SPREAD NORTH AND EAST MONDAY ACROSS MOST OF
WESTERN KY AND SW INDIANA.
A STRONG COLD FRONT WILL SWING SOUTHEAST ACROSS THE LOWER OHIO
VALLEY ON MONDAY NIGHT. AS THIS COLD FRONT ENCOUNTERS MOISTURE
ASSOCIATED WITH THE SOUTHERN STREAM SHORTWAVE...NUMEROUS SHOWERS
AND SOME ISOLATED THUNDER WILL PERSIST ACROSS MUCH OF OUR REGION.
WHILE STORM TOTAL QPF IS GENERALLY UNDER AN INCH...THERE COULD BE
SOME ISOLATED HEAVIER AMOUNTS. HEAVIEST TOTALS WILL BE IN KHOP
AREA. DUE TO WIDESPREAD CLOUDS AND WEAK WIND FIELDS...CONVECTIVE
DEVELOPMENT SHOULD BE LIMITED IN COVERAGE AND INTENSITY.
ONCE THE COLD FRONT PASSES MONDAY NIGHT...WINDS WILL INCREASE FROM
THE NORTHWEST. 850 MB WINDS WILL BE AVERAGING 25 TO 30 KNOTS TUESDAY.
SURFACE WIND GUSTS MAY REACH 30 MPH WITH STRONG MIXING ON TUESDAY.
STRONG DRYING BEHIND THE FRONT WILL RESULT IN RAPID CLEARING ON
TUESDAY MORNING...BUT 850 MB TEMPS WILL BE FALLING QUICKLY INTO
THE SINGLE DIGITS. THEREFORE...HIGHS WILL NOT GET OUT OF THE 60S
DESPITE A FAIRLY MILD START TO THE DAY IN THE 50S.
TUESDAY NIGHT WILL BE CHILLY AS A SURFACE RIDGE PASSES OVER THE
OHIO VALLEY. CLEAR SKIES AND NEARLY CALM WINDS WILL BE FAVORABLE
FOR STRONG RADIATIONAL COOLING. MOS GUIDANCE IS OFTEN TOO HIGH IN
SUCH CASES...AND FORECAST WILL BE WEIGHTED TOWARD THE COOLER 2M
NAM TEMPS. THIS YIELDS UPPER 30S IN MANY PLACES...WHICH SUGGESTS
THE POSSIBILITY OF SOME PATCHY FROST.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED 308 PM CDT SUN SEP 16 2012
TROUGHING ALOFT OVER THE WESTERN GREAT LAKES TO BEGIN THE PERIOD
IS EXPECTED TO AMPLIFY AND DEVELOP SOUTHWARD TOWARD THE LOWER OHIO
VALLEY/MID MISSISSIPPI VALLEY FRIDAY INTO SATURDAY. CONFIDENCE HAS
IMPROVED IN KEEPING THE FORECAST DRY WEDNESDAY THROUGH THURSDAY
NIGHT...AS NO RECENT MODELS HAVE ROTATED A SIGNIFICANT ENOUGH
DISTURBANCE THROUGH THE BASE OF THE TROUGH TO DRAG PRECIPITATION
INTO THE FOUR STATE REGION.
CONFIDENCE IS ALSO INCREASING IN TIMING OF THE PRIMARY COLD FRONT
THROUGH THE REGION FRIDAY AND FRIDAY NIGHT...AS THE 12Z GFS AND
ECMWF BOTH HAVE THIS GENERAL TIMING. POPS ARE STILL RATHER LOW THESE
PERIODS...AS THE MODELS NEED TO SHOW SOME STABILITY FIRST.
ALSO...SURFACE RIDGING IS EXPECTED TO PERSIST BETWEEN HERE AND THE
GULF COAST...SO THERE WILL BE LITTLE IN THE WAY OF RETURN FLOW OF
MOISTURE INTO THE FRONT. THAT SAID...THE MID AND UPPER LEVEL FORCING
MAY BE STRONG ENOUGH TO GENERATE SOME ELEVATED INSTABILITY...SO KEPT
THUNDER MENTION AREAWIDE FRIDAY AND FRIDAY NIGHT.
SLIGHT POPS ARE FORECAST FOR SATURDAY AND SATURDAY NIGHT TO ACCOUNT
FOR THE 00Z ECMWF TIMING OF THE FRONT. THE 00Z ECMWF ENSEMBLES DID
SHOW SOME SUPPORT FOR THE OLD OPERATIONAL RUN...SO CANNOT RULE IT
OUT JUST YET.
AS FOR TEMPERATURES...IT WILL FEEL RATHER COOLISH WITH HIGHS NEAR 70
AND PLENTY OF SUNSHINE WEDNESDAY. A NICE WARMING TREND IS EXPECTED
THURSDAY AND FRIDAY WITH A FEW 80S POSSIBLE ON FRIDAY. LOOKS LIKE
PLEASANT EARLY FALL CONDITIONS FOR NEXT WEEKEND...ESPECIALLY IF THE
OLD ECMWF IS NOT RIGHT. TEMPERATURES WILL BE A COUPLE OF CATEGORIES
BELOW NORMAL...BUT STILL IN THE 70S FOR HIGHS.
&&
.AVIATION...
ISSUED AT 1205 AM CDT MON SEP 17 2012
VFR CONDITIONS WILL GIVE WAY TO A NORTHWARD RETURN OF SHOWERS AND
LOCAL IFR CONDITIONS OVERNIGHT. IFR CEILINGS AND VISIBILITIES WILL
IMPACT PRIMARILY THE KCGI/KPAH SITES THROUGH DAYBREAK. THE SHOWER
ACTIVITY AND MVFR CEILINGS AND VISIBILITIES WILL SPREAD ACROSS THE
KEVV/KOWB SITES AFTER DAYBREAK MONDAY. THE SHOWERS WILL PERSIST INTO
MONDAY AFTERNOON...AND MAY BE ACCOMPANIED BY AN INCREASE IN
THUNDERSTORM COVERAGE. LIGHT WINDS OVERNIGHT WILL BECOME SOUTHERLY
ON MONDAY.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
MO...NONE.
IL...NONE.
IN...NONE.
&&
$$
SHORT TERM...MY
LONG TERM....DRS
AVIATION...RJP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 AM EDT MON SEP 17 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A W FLOW ALF OVER
THE GRT LKS BTWN DEEPENING TROF IN SCNTRL CAN AND PROGRESSIVE SHRTWV
RDG MOVING THRU THE GRT LKS. THERE IS A WEAK SHRTWV EMBEDDED IN THIS
FLOW MOVING THRU WRN LK SUP EARLY THIS AFTN...BUT DRY AIRMASS
DOMINATING THE AREA AND SHOWN ON THE 12Z RAOBS IS LIMITING ANY
ACCOMPANYING WX TO JUST SOME PATCHY MID/HI CLDS. A STEADY WSW LLVL
FLOW BTWN SFC HI PRES MOVING INTO THE MID ATLANTIC STATES AND A LO
PRES TROF OVER THE KEWEENAW/WRN LK SUP ASSOCIATED WITH THE SHRTWV IS
BEGINNING TO DRAW MORE SFC-H9 MSTR SHOWN ON THE 12Z MPX RAOB TOWARD
THE AREA...BUT SFC DEWPTS HAVE MIXED OUT TO AS LO AS THE MID 40S AS
OF EARLY THIS AFTN OVER THE CWA IN ADVANCE OF THIS LLVL MOISTENING.
FARTHER TO THE NW...A SHARP COLD FNT STRETCHES FM NW ONTARIO ACRS MN
INTO SDAKOTA. DUE TO THE DRYNESS OF AIRMASS AHEAD OF THIS FNT...
THERE IS CURRENTLY NO SHRA AHEAD OF THIS BNDRY. BUT MORE CLDS/SOME
-SHRA ARE EVIDENT OVER NDAKOTA IN THE COLD AIR TRAILING THE FNT WITH
APRCH OF SHRTWVS EMBEDDED IN THE DEEPENING TROF OVER SCNTRL CAN AND
ACCOMPANYING DPVA/H7-3 QVECTOR CNVGC AS WELL AS UPR DVGC IN RRQ OF
ASSOCIATED H3 JET MAX NEAR LK WINNIPEG.
LATE THIS AFTN/EARLY EVNG...ISSUED WILDFIRE POTENTIAL STATEMENT
EARLIER IN THE SHIFT TO ACCOUNT FOR COMBINATION OF WELL ABV NORMAL
TEMPS...MIN RH FALLING TO 30-35 PCT...GUSTY WSW WINDS ENHANCED BY
DEEP MIXING...AND RECENT DRYNESS. THE MOST CRITICAL CONDITIONS ARE
OVER THE SCNTRL...WHERE SHARPER PRES GRADIENT/HIER WINDS ARE
EVIDENT. QUESTION IS WHETHER RETURNING LLVL MSTR SHOWN ON THE 12Z
MPX RAOB MIGHT CAUSE SOME CONVECTION ON INCOMING LO PRES TROF UNDER
SOME DPVA/H85-5 QVECTOR CNVGC ASSOCIATED WITH APRCHG SHRTWV. RECENT
GFS RUNS HAVE BEEN QUITE CONSISTENT SHOWING SOME CONVECTION. SINCE
THE 12Z RAPID REFRESH RUC MODEL...THE FINER RES CNDN MODEL...AND THE
NAM HINT SOME CONVECTION WL IMPACT MAINLY THE CNTRL ZNS WHERE LLVL
MOISTENING AND DYNAMICS COME INTO PHASE NEAR PEAK HEATING TIME...
MAINTAINED SCHC POPS OVER THE CNTRL DESPITE MID LVL DRYNESS THAT WL
LIMIT COVERAGE OF ANY ASSOCIATED SHRA/TS TO ISOLD.
TNGT...ANY INSTABILITY SHRA/TS WL DISSIPATE WITH LOSS OF DAYTIME
HEATING/ARRIVAL OF SOME DNVA/H85-5 QVECTOR DVGC IN THE WAKE OF
INITIAL SHRTWV PASSAGE. THEN COLD FNT ASSOCIATED WITH DEEPENING TROF
IN CANADA IS PROGGED TO PUSH ACRS THE W HALF OF UPR MI BY 12Z MON.
SINCE THE SHARPEST H7-3 QVECTOR CNVGC ASSOCIATED WITH SHRTWVS MOVING
THRU THE AMPLIFYING UPR TROF/UPR DVGC IN RRQ OF H3 JET MAX MOVING
INTO NW ONTARIO IS FCST TO FOLLOW THE FROPA...EXPECT THE BULK OF ANY
PCPN TO FALL ON THE COLD SIDE OF THE BNDRY...AS IS OBSVD TODAY IN
THE NRN PLAINS. GOING POPS INCRSG TOWARD CATEGORICAL OVER THE W
APPEAR PRETTY MUCH ON TRACK...BUT DID CUT POPS OVER THE E HALF WITH
AN ABSENCE OF UPR FORCING IN THAT AREA WITHIN DRIER AIRMASS AHEAD OF
THE FROPA.
MON...AREA OF SHRA/CATEGORICAL POPS OVER THE W HALF IN THE MRNG
SHOULD SPREAD INTO THE E AS UPR TROF AXIS SHIFTS SLOWLY TO THE E AND
AREA OF IMPRESSIVE H7-3 QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET TO
THE N SHIFTS TO THE E FOLLOWING SFC COLD FROPA. ALTHOUGH MODELS
INDICATE SOME MID LVL DRYING MIGHT IMPACT THE W IN THE AFTN...
ARRIVAL OF COLDER H85 AIR...WITH TEMPS AT THAT LVL FCST NEAR 0C OVER
THE W LATER IN THE DAY...IN CYC NLY FLOW TO W OF SFC LO THAT DVLPS
ON THE COLD FNT TO THE E SHOULD MAINTAIN LK ENHANCED SHOWERS IN THAT
AREA THRU 00Z TUE. ALTHOUGH TEMPS MIGHT WARM A BIT OVER THE E BEFORE
COLD FROPA/THICKER CLDS ARRIVE...READINGS ARE LIKELY TO FALL
FOLLOWING THE FROPA. SO NON-DIURNAL TEMP CURVE WITH STEADY/SLOWLY
FALLING TEMPS AT MOST PLACES IN THE AFTN APPEARS IN ORDER. DID
RETAIN A MENTION OF TS OVER THE E NEAR AND JUST BEHIND FROPA TIME AS
NAM FCST SDNGS HINT AT MUCAPE UP TO 500 J/KG. WITH A GUSTY N WIND...
SHRA... AND FALLING TEMPS THRU THE 50S...MON WL HAVE A DISTINCT
AUTUMNAL FEEL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
MAIN CONCERN IN THE MON NIGHT-WED TIME PERIOD CONTINUES TO BE
POPS...AND ALSO THE POSSIBILITY OF A HARD FREEZE TUESDAY NIGHT
ACROSS THE INTERIOR.
NO MAJOR CHANGES OF FORECAST THINKING FOR MONDAY NIGHT. THE UPPER
TROUGH GRADUALLY SETTLES ACROSS THE UPPER LAKES MONDAY
NIGHT...CENTERED OVER LAKE SUPERIOR BY TUESDAY MORNING. DESPITE THE
SURFACE LOW MOVING NE AND AWAY FROM THE REGION...A LAKE AGGREGATE
TROUGH WILL PERSIST ACROSS THE LAKE AS THE UPPER TROUGH MOVES
OVERHEAD. THIS WILL KEEP PBL WINDS PEGGED TO A NORTHERLY DIRECTION
ACROSS THE LAKE WHICH COMBINED WITH STEEPENING LOW LEVEL LAPSE RATES
AS THE 850MB TEMPS DROP TO -3C SHOULD FAVOR A FAIRLY PERSISTANT RAIN
ACROSS NORTH CENTRAL UPPER MICHIGAN MONDAY NIGHT. THERE ARE SOME
DIFFERENCES BETWEEN THE GFS AND NAM REGARDING THE EVOLUTION OF LOW
LEVEL WIND FLOW. THE GFS SUGGESTS THE WIND WILL BACK SLIGHTLY MONDAY
NIGHT OVER UPPER MI WHICH WOULD KEEP THE HEAVIEST PCPN JUST TO THE
EAST OF MARQUETTE. MEANWHILE...THE NAM WANTS TO KEEP THE WINDS A
LITTLE EAST OF NORTH...WHICH WOULD BE HIGHLY FAVORABLE FOR THE
HIGHER ELEVATIONS WEST OF MARQUETTE. WOULD NOT BE SURPRISED IF THE
GFS WIND VERIFIES...BUT IT MAY NOT MAKE A DIFFERENCE IN PCPN CHANCES
GIVEN THE LAKE ENHANCED NATURE OF THE PCPN VS. LAKE EFFECT. THE NAM
AND GFS ALSO SUGGEST THAT THE RAIN WILL DIMINISH MON NIGHT SOME OF
THE MID LEVEL MOISTURE BRIEFLY SCOURS OUT BEFORE A REINFORCING SHOT
OF MOISTURE MOVES IN BY TUE MORNING. ALTHOUGH THIS MAY HAPPEN...THE
FACT THAT THE LAKE INDUCED EQULIBRIUM LEVEL RISES TO OVER 20 KFT
OVERNIGHT MONDAY AND LARGE SCALE FORCING PERSISTS AS THE UPPER
TROUGH MOVES OVERHEAD SHOULD HELP TO OFFSET ANY MID LEVEL DRYING.
THE 4KM NAM NEST AND THE LOCAL WRF-ARW SUGGEST THE LAKE ENHANCED
PCPN WILL DEVELOP IN EARNEST AS SOON AS THE 850MB TEMPS DROP...SOON
AFTER 00Z. IN ADDITION...THE MORE LAKE ENHANCED NATURE OF THE PCPN
/VS LAKE EFFECT/ WOULD SUGGEST A MORE EVENLY DISTRUBUTED AREA OF
PCPN ACROSS ALL OF NORTH CENTRAL UPPER MI. WITH ALL OF THIS BEING
SAID...WILL KEEP CATEGORICAL POPS FOR MUCH OF NORTH CENTRAL UPPER
MICHIGAN CLOSER TO LAKE SUPERIOR...SIMILAR TO PREVIOUS FORECASTS. AS
FOR THE FAR EAST...PCPN MAY LIGHTEN UP MON NIGHT AS NORTHERLY PBL
FLOW NOT TERRRIBLY FAVORABLE FOR PCPN IN THAT AREA.
WITH THE UPPER TROUGH OVERHEAD ON TUESDAY...AND NEUTRAL TO SLIGHTLY
CYCLONIC PBL FLOW...WILL OPT TO MAINTAIN POPS AND RAISE THEM
SLIGHTLY TUESDAY NEAR LAKE SUPERIOR. AS THE TROUGH EXITS DURING THE
DAY...THE ASSOCIATED MID LVL FORCING WILL EXIT. THIS WILL ALLOW FOR
THE SURFACE RIDGING TO BUILD IN DURING THE DAY AND AS SUCH SHOULD
ALLOW FOR LAKE EFFECT PCPN TO GRADUALLY DIMINISH BY EVENING. AM NOT
IN TOO MUCH OF A HURRY TO END PCPN ON TUESDAY THOUGH...AS THE RIDGE
AXIS REALLY DOES NOT BUILD IN UNTIL AFTER 00Z WED. TEMPS WILL
STRUGGLE TO REACH 50 ACROSS THE INTERIOR DUE TO CLOUDS AND SHOWERS.
IN FACT...ALL NWP WANTS TO KEEP THE INTERIOR IN THE MID-UPPER 40S ON
TUESDAY. THIS SEEMS REASONABLE ESPECIALLY IF CLOUDS PERSIST...AND
HAVE THEREFORE LOWERED TEMPS ACROSS THE ENTIRE AREA ON
TUESDAY...WITH MOST INTERIOR SECTIONS STAYING IN THE 40S.
ANY REMAINING SHOWERS SHOULD END EARLY TUE EVENING...THEN THE RIDGE
BUILDS IN. THIS RIDGING COMBINED WITH PRECIPITABLE WATER VALUES AS
LOW AS 0.45 INCH SHOULD ALLOW FOR SKIES TO CLEAR OUT ACROSS THE
WEST. LAKE CLOUDS SHOULD HANG ON EAST...BUT EVEN THERE IT MAY CLEAR
OUT BY MORNING. REGARDLESS...WITH CLEAR SKIES AND LIGHT WINDS...IT
SHOULD GET COLD ACROSS THE INTERIOR. AM NOW THINKING A HARD FREEZE
IS IN STORE BY WED MORNING FOR THE INTERIOR WEST. EVEN THE RAW NAM
WHICH USUALLY HAS A WARM BIAS DURING RADIATIONAL COOLING HAS TEMPS
ACROSS IRON COUNTY IN THE 20S...AND THE GFS HAS 2M TEMPS IN THE
LOWER 30S. NAM MOS GUIDANCE SUGGEST SIMILAR TO COLDER TEMPS FOR TUE
NIGHT. WILL THEREFORE LOWER TEMPS ACROSS THE ENTIRE AREA TUE NIGHT.
SOME MODEL DIFFERENCES REGARDING THE NEXT SYSTEM. THE GFS IS MUCH
FASTER...UP TO 12 HRS...BRINIGING PCPN IN BY LUNCHTIME WED.
MEANWHILE...THE NAM AND GEM ARE MUCH SLOWER...NOT BRINGING IN PCPN
UNTIL WED EVENING. THE COMBINATION OF THE INCREASING WARM
ADVECTION/ISENTROPIC LIFT AND INCREASING MID LVL MOISTURE ACROSS THE
WEST WED AFTN IN THE NAM WOULD IMPLY AT LEAST A CHANCE FOR RAIN WED
AFTN DESPITE THE MODEL NOT PRINTING OUT MUCH QPF. WILL THEREFORE GO
WITH 30 PCPN CHANCE FOR SHOWERS WED AFTN FOR WESTERN UPPER MI. WILL
KEEP A DRY FCST FOR THE REMAINDER OF THE AREA.
IN THE EXTENDED /WED NIGHT-NEXT SUNDAY/...THE FULL AMPLITUDE LONG
WAVE TROUGH WILL PERSIST FROM HUDSON BAY THROUGH THE GREAT LAKES
REGION THROUGH THE PERIOD. THIS WILL KEEP THE WEATHER FAIRLY
UNSETTLED THROUGH SATURDAY. THE NUMERICAL GUIDANCE IS IN GOOD
AGREEMENT REGARDING THE LONG WAVE...BUT DIFFER SOMEWHAT ON SPECIFIC
DETAILS REGARDING INDIVIDUAL SHORT WAVES AND AS SUCH THEY DIFFER ON
EXACT POSITION OF THE LONG WAVE TROUGH. THE MAIN OUTLIER WITH THE
00Z RUN IS THE OPERATIONAL ECMWF WHICH KEEPS THE MAIN TROUGH
POSITIVLY TILTED WITH THE TROUGH AXIS FURTHER WEST. THIS IS LIKELY
DUE TO THAT MODEL ALLOWING STRONGER SHORT WAVE ENERGY TO DIVE DOWN
THE BACK SIDE OF THE UPPER TROUGH THURSDAY INTO FRIDAY. AT THIS
TIME...THIS IS NOT SUPPORTED BY THE GFS...NOR THE MAJORITY OF THE
ENSEMBLE MEMBERS FROM THE GFS AND ECMWF. WILL THEREFORE TREND THE
FORECAST TOWARD THE GFS/GEM COMPROMISE...BUT THE REALITY OF THE
MATTER IS THAT EITHER SOLUTION WOULD MAINTAIN UNSETTLED WEATHER FOR
THE AREA FOR MUCH OF THE EXTENDED. THERE WILL BE PERIODS OF DRY
WEATHER...BUT GIVEN THE UNCERTAINTY OF EXACT SHORT WAVE POSITIONS
ESPECIALLY FOR LATE INTO THE WEEK...IT WILL BE TOUGH TO PIN DOWN
SPECIFICS. WITH THAT BEING SAID...WILL NEED TO GO WITH CHANCE POPS
EACH DAY OF THE EXTENDED THROUGH SATURDAY. THE BEST CHANCE FOR RAIN
MAY BE FRIDAY INTO FRIDAY NIGHT WHERE THE GFS AND GEM BOTH AGREE ON
A WAVE MOVING ACROSS THE UPPER LAKES WITH LOW PRESSURE ACROSS THE
AREA. IN FACT...EVEN THE ECMWF SHOWS PCPN FRIDAY. BY SUNDAY...THE
GFS SUGGESTS THAT THE TROUGH WILL SLOWLY EXIT EAST OF THE
AREA...ALLOWING SOME DRYING TO MOVE IN. WILL THEREFORE GO WITH A DRY
FORECAST FOR NOW ON SUNDAY...BUT THAT IS SUBJECT TO CHANGE IF THE
TROUGH IS A LITTLE SLOWER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 138 AM EDT MON SEP 17 2012
AFTER PASSAGE OF COLD FRONT...ABUNDANT MOISTURE WILL PULL WIDESPREAD
RAIN AND CLOUDS EASTWARD ACROSS THE TAF SITES OVERNIGHT. EXPECT SOME
LOWERING OF VIS/CIGS AS A RESULT...THOUGH LATEST MODEL GUIDANCE SHOWS
A LOW LEVEL DRY AIR POCKET WHICH COULD INHIBIT SOME OF THE IFR
VIS/CIGS EXPECTED IN LAST TAF ISSUANCE. CHOSE TO KEEP SITES
MVFR...THOUGH SOME AMENDMENTS FOR EXACT TIMINGS AND CIG/VIS MAY NEED
TO BE MADE. THE EXCEPTION IS KSAW...WHICH DUE TO MOIST COLD AIRMASS
PULLING STRONG WINDS OFF THE WARM LAKE...COULD SEE HEAVIEST RAIN
SHOWERS...SO SOME IFR CONDITIONS ARE POSSIBLE. MAIN FORCING WILL
MOVE OFF TO THE EAST DURING THE AFTERNOON BRINGING RAIN TO AN END AT
KCMX. HOWEVER...COLD AIRMASS OVER WARM LAKE AND RESULTING STRONG N
WINDS WILL MAKE CONDITIONS FAVORABLE FOR LAKE EFFECT RAIN SHOWERS
/TRANSITION FROM RA TO SHRA IN TAF/ FOR KIWD AND KSAW THROUGH
REMAINDER OF TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT SUN SEP 16 2012
EXPECT RELATIVELY LIGHT WINDS UNDER 20 KTS FOR MOST OF THIS EVENING
OVER THE LAKE WITH FAIRLY HI STABILITY/A WEAK LO PRES TROF CROSSING
THE AREA. THEN EXPECT A WIND SHIFT TO THE NNW WITH THE PASSAGE OF A
STRONG COLD FRONT BY LATE EVENING OVER THE W AND THEN ON MON MORNING
OVER THE E HALF. AS COLDER AIR FOLLOWS THE FRONT OVER THE RELATIVELY
WARM WATERS OF LAKE SUPERIOR AND STABILITY DECREASES...EXPECT
STRONGER N WINDS TO 25 TO 30 KTS TO DEVELOP W TO E. BUT SINCE LATEST
GUIDANCE INDICATES THE PRES GRADIENT WILL BE WEAKER THAN EXPECTED ON
PREVIOUS SHIFTS...GALES NOW APPEAR UNLIKELY. SO THE GOING GALE WATCH
THAT WAS IN EFFECT ON MON OVER PORTIONS OF THE W HALF WAS DROPPED.
NORTH WINDS WILL PERSIST MONDAY NIGHT INTO TUESDAY BEFORE GRADUALLY
SHIFTING TO THE NW THEN W BY TUESDAY EVENING. ANOTHER LOW PRESSURE
TROUGH WILL APPROACH WED THEN PASS ACROSS THE LAKE WED NIGHT. AHEAD
OF THE TROUGH...WINDS WILL TURN SOUTHERLY AT 15-25 KT...THEN WILL
TURN W-NW BY THU MORNING. OTHER THAN SOME GUSTS CLOSE TO GALE FORCE
MONDAY EVENING...GALES ARE NOT EXPECTED AT THIS TIME THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MRD
AVIATION...JMW
MARINE...KC/MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
116 AM EDT MON SEP 17 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A W FLOW ALF OVER
THE GRT LKS BTWN DEEPENING TROF IN SCNTRL CAN AND PROGRESSIVE SHRTWV
RDG MOVING THRU THE GRT LKS. THERE IS A WEAK SHRTWV EMBEDDED IN THIS
FLOW MOVING THRU WRN LK SUP EARLY THIS AFTN...BUT DRY AIRMASS
DOMINATING THE AREA AND SHOWN ON THE 12Z RAOBS IS LIMITING ANY
ACCOMPANYING WX TO JUST SOME PATCHY MID/HI CLDS. A STEADY WSW LLVL
FLOW BTWN SFC HI PRES MOVING INTO THE MID ATLANTIC STATES AND A LO
PRES TROF OVER THE KEWEENAW/WRN LK SUP ASSOCIATED WITH THE SHRTWV IS
BEGINNING TO DRAW MORE SFC-H9 MSTR SHOWN ON THE 12Z MPX RAOB TOWARD
THE AREA...BUT SFC DEWPTS HAVE MIXED OUT TO AS LO AS THE MID 40S AS
OF EARLY THIS AFTN OVER THE CWA IN ADVANCE OF THIS LLVL MOISTENING.
FARTHER TO THE NW...A SHARP COLD FNT STRETCHES FM NW ONTARIO ACRS MN
INTO SDAKOTA. DUE TO THE DRYNESS OF AIRMASS AHEAD OF THIS FNT...
THERE IS CURRENTLY NO SHRA AHEAD OF THIS BNDRY. BUT MORE CLDS/SOME
-SHRA ARE EVIDENT OVER NDAKOTA IN THE COLD AIR TRAILING THE FNT WITH
APRCH OF SHRTWVS EMBEDDED IN THE DEEPENING TROF OVER SCNTRL CAN AND
ACCOMPANYING DPVA/H7-3 QVECTOR CNVGC AS WELL AS UPR DVGC IN RRQ OF
ASSOCIATED H3 JET MAX NEAR LK WINNIPEG.
LATE THIS AFTN/EARLY EVNG...ISSUED WILDFIRE POTENTIAL STATEMENT
EARLIER IN THE SHIFT TO ACCOUNT FOR COMBINATION OF WELL ABV NORMAL
TEMPS...MIN RH FALLING TO 30-35 PCT...GUSTY WSW WINDS ENHANCED BY
DEEP MIXING...AND RECENT DRYNESS. THE MOST CRITICAL CONDITIONS ARE
OVER THE SCNTRL...WHERE SHARPER PRES GRADIENT/HIER WINDS ARE
EVIDENT. QUESTION IS WHETHER RETURNING LLVL MSTR SHOWN ON THE 12Z
MPX RAOB MIGHT CAUSE SOME CONVECTION ON INCOMING LO PRES TROF UNDER
SOME DPVA/H85-5 QVECTOR CNVGC ASSOCIATED WITH APRCHG SHRTWV. RECENT
GFS RUNS HAVE BEEN QUITE CONSISTENT SHOWING SOME CONVECTION. SINCE
THE 12Z RAPID REFRESH RUC MODEL...THE FINER RES CNDN MODEL...AND THE
NAM HINT SOME CONVECTION WL IMPACT MAINLY THE CNTRL ZNS WHERE LLVL
MOISTENING AND DYNAMICS COME INTO PHASE NEAR PEAK HEATING TIME...
MAINTAINED SCHC POPS OVER THE CNTRL DESPITE MID LVL DRYNESS THAT WL
LIMIT COVERAGE OF ANY ASSOCIATED SHRA/TS TO ISOLD.
TNGT...ANY INSTABILITY SHRA/TS WL DISSIPATE WITH LOSS OF DAYTIME
HEATING/ARRIVAL OF SOME DNVA/H85-5 QVECTOR DVGC IN THE WAKE OF
INITIAL SHRTWV PASSAGE. THEN COLD FNT ASSOCIATED WITH DEEPENING TROF
IN CANADA IS PROGGED TO PUSH ACRS THE W HALF OF UPR MI BY 12Z MON.
SINCE THE SHARPEST H7-3 QVECTOR CNVGC ASSOCIATED WITH SHRTWVS MOVING
THRU THE AMPLIFYING UPR TROF/UPR DVGC IN RRQ OF H3 JET MAX MOVING
INTO NW ONTARIO IS FCST TO FOLLOW THE FROPA...EXPECT THE BULK OF ANY
PCPN TO FALL ON THE COLD SIDE OF THE BNDRY...AS IS OBSVD TODAY IN
THE NRN PLAINS. GOING POPS INCRSG TOWARD CATEGORICAL OVER THE W
APPEAR PRETTY MUCH ON TRACK...BUT DID CUT POPS OVER THE E HALF WITH
AN ABSENCE OF UPR FORCING IN THAT AREA WITHIN DRIER AIRMASS AHEAD OF
THE FROPA.
MON...AREA OF SHRA/CATEGORICAL POPS OVER THE W HALF IN THE MRNG
SHOULD SPREAD INTO THE E AS UPR TROF AXIS SHIFTS SLOWLY TO THE E AND
AREA OF IMPRESSIVE H7-3 QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET TO
THE N SHIFTS TO THE E FOLLOWING SFC COLD FROPA. ALTHOUGH MODELS
INDICATE SOME MID LVL DRYING MIGHT IMPACT THE W IN THE AFTN...
ARRIVAL OF COLDER H85 AIR...WITH TEMPS AT THAT LVL FCST NEAR 0C OVER
THE W LATER IN THE DAY...IN CYC NLY FLOW TO W OF SFC LO THAT DVLPS
ON THE COLD FNT TO THE E SHOULD MAINTAIN LK ENHANCED SHOWERS IN THAT
AREA THRU 00Z TUE. ALTHOUGH TEMPS MIGHT WARM A BIT OVER THE E BEFORE
COLD FROPA/THICKER CLDS ARRIVE...READINGS ARE LIKELY TO FALL
FOLLOWING THE FROPA. SO NON-DIURNAL TEMP CURVE WITH STEADY/SLOWLY
FALLING TEMPS AT MOST PLACES IN THE AFTN APPEARS IN ORDER. DID
RETAIN A MENTION OF TS OVER THE E NEAR AND JUST BEHIND FROPA TIME AS
NAM FCST SDNGS HINT AT MUCAPE UP TO 500 J/KG. WITH A GUSTY N WIND...
SHRA... AND FALLING TEMPS THRU THE 50S...MON WL HAVE A DISTINCT
AUTUMNAL FEEL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
MAIN CONCERN IN THE MON NIGHT-WED TIME PERIOD CONTINUES TO BE
POPS...AND ALSO THE POSSIBILITY OF A HARD FREEZE TUESDAY NIGHT
ACROSS THE INTERIOR.
NO MAJOR CHANGES OF FORECAST THINKING FOR MONDAY NIGHT. THE UPPER
TROUGH GRADUALLY SETTLES ACROSS THE UPPER LAKES MONDAY
NIGHT...CENTERED OVER LAKE SUPERIOR BY TUESDAY MORNING. DESPITE THE
SURFACE LOW MOVING NE AND AWAY FROM THE REGION...A LAKE AGGREGATE
TROUGH WILL PERSIST ACROSS THE LAKE AS THE UPPER TROUGH MOVES
OVERHEAD. THIS WILL KEEP PBL WINDS PEGGED TO A NORTHERLY DIRECTION
ACROSS THE LAKE WHICH COMBINED WITH STEEPENING LOW LEVEL LAPSE RATES
AS THE 850MB TEMPS DROP TO -3C SHOULD FAVOR A FAIRLY PERSISTANT RAIN
ACROSS NORTH CENTRAL UPPER MICHIGAN MONDAY NIGHT. THERE ARE SOME
DIFFERENCES BETWEEN THE GFS AND NAM REGARDING THE EVOLUTION OF LOW
LEVEL WIND FLOW. THE GFS SUGGESTS THE WIND WILL BACK SLIGHTLY MONDAY
NIGHT OVER UPPER MI WHICH WOULD KEEP THE HEAVIEST PCPN JUST TO THE
EAST OF MARQUETTE. MEANWHILE...THE NAM WANTS TO KEEP THE WINDS A
LITTLE EAST OF NORTH...WHICH WOULD BE HIGHLY FAVORABLE FOR THE
HIGHER ELEVATIONS WEST OF MARQUETTE. WOULD NOT BE SURPRISED IF THE
GFS WIND VERIFIES...BUT IT MAY NOT MAKE A DIFFERENCE IN PCPN CHANCES
GIVEN THE LAKE ENHANCED NATURE OF THE PCPN VS. LAKE EFFECT. THE NAM
AND GFS ALSO SUGGEST THAT THE RAIN WILL DIMINISH MON NIGHT SOME OF
THE MID LEVEL MOISTURE BRIEFLY SCOURS OUT BEFORE A REINFORCING SHOT
OF MOISTURE MOVES IN BY TUE MORNING. ALTHOUGH THIS MAY HAPPEN...THE
FACT THAT THE LAKE INDUCED EQULIBRIUM LEVEL RISES TO OVER 20 KFT
OVERNIGHT MONDAY AND LARGE SCALE FORCING PERSISTS AS THE UPPER
TROUGH MOVES OVERHEAD SHOULD HELP TO OFFSET ANY MID LEVEL DRYING.
THE 4KM NAM NEST AND THE LOCAL WRF-ARW SUGGEST THE LAKE ENHANCED
PCPN WILL DEVELOP IN EARNEST AS SOON AS THE 850MB TEMPS DROP...SOON
AFTER 00Z. IN ADDITION...THE MORE LAKE ENHANCED NATURE OF THE PCPN
/VS LAKE EFFECT/ WOULD SUGGEST A MORE EVENLY DISTRUBUTED AREA OF
PCPN ACROSS ALL OF NORTH CENTRAL UPPER MI. WITH ALL OF THIS BEING
SAID...WILL KEEP CATEGORICAL POPS FOR MUCH OF NORTH CENTRAL UPPER
MICHIGAN CLOSER TO LAKE SUPERIOR...SIMILAR TO PREVIOUS FORECASTS. AS
FOR THE FAR EAST...PCPN MAY LIGHTEN UP MON NIGHT AS NORTHERLY PBL
FLOW NOT TERRRIBLY FAVORABLE FOR PCPN IN THAT AREA.
WITH THE UPPER TROUGH OVERHEAD ON TUESDAY...AND NEUTRAL TO SLIGHTLY
CYCLONIC PBL FLOW...WILL OPT TO MAINTAIN POPS AND RAISE THEM
SLIGHTLY TUESDAY NEAR LAKE SUPERIOR. AS THE TROUGH EXITS DURING THE
DAY...THE ASSOCIATED MID LVL FORCING WILL EXIT. THIS WILL ALLOW FOR
THE SURFACE RIDGING TO BUILD IN DURING THE DAY AND AS SUCH SHOULD
ALLOW FOR LAKE EFFECT PCPN TO GRADUALLY DIMINISH BY EVENING. AM NOT
IN TOO MUCH OF A HURRY TO END PCPN ON TUESDAY THOUGH...AS THE RIDGE
AXIS REALLY DOES NOT BUILD IN UNTIL AFTER 00Z WED. TEMPS WILL
STRUGGLE TO REACH 50 ACROSS THE INTERIOR DUE TO CLOUDS AND SHOWERS.
IN FACT...ALL NWP WANTS TO KEEP THE INTERIOR IN THE MID-UPPER 40S ON
TUESDAY. THIS SEEMS REASONABLE ESPECIALLY IF CLOUDS PERSIST...AND
HAVE THEREFORE LOWERED TEMPS ACROSS THE ENTIRE AREA ON
TUESDAY...WITH MOST INTERIOR SECTIONS STAYING IN THE 40S.
ANY REMAINING SHOWERS SHOULD END EARLY TUE EVENING...THEN THE RIDGE
BUILDS IN. THIS RIDGING COMBINED WITH PRECIPITABLE WATER VALUES AS
LOW AS 0.45 INCH SHOULD ALLOW FOR SKIES TO CLEAR OUT ACROSS THE
WEST. LAKE CLOUDS SHOULD HANG ON EAST...BUT EVEN THERE IT MAY CLEAR
OUT BY MORNING. REGARDLESS...WITH CLEAR SKIES AND LIGHT WINDS...IT
SHOULD GET COLD ACROSS THE INTERIOR. AM NOW THINKING A HARD FREEZE
IS IN STORE BY WED MORNING FOR THE INTERIOR WEST. EVEN THE RAW NAM
WHICH USUALLY HAS A WARM BIAS DURING RADIATIONAL COOLING HAS TEMPS
ACROSS IRON COUNTY IN THE 20S...AND THE GFS HAS 2M TEMPS IN THE
LOWER 30S. NAM MOS GUIDANCE SUGGEST SIMILAR TO COLDER TEMPS FOR TUE
NIGHT. WILL THEREFORE LOWER TEMPS ACROSS THE ENTIRE AREA TUE NIGHT.
SOME MODEL DIFFERENCES REGARDING THE NEXT SYSTEM. THE GFS IS MUCH
FASTER...UP TO 12 HRS...BRINIGING PCPN IN BY LUNCHTIME WED.
MEANWHILE...THE NAM AND GEM ARE MUCH SLOWER...NOT BRINGING IN PCPN
UNTIL WED EVENING. THE COMBINATION OF THE INCREASING WARM
ADVECTION/ISENTROPIC LIFT AND INCREASING MID LVL MOISTURE ACROSS THE
WEST WED AFTN IN THE NAM WOULD IMPLY AT LEAST A CHANCE FOR RAIN WED
AFTN DESPITE THE MODEL NOT PRINTING OUT MUCH QPF. WILL THEREFORE GO
WITH 30 PCPN CHANCE FOR SHOWERS WED AFTN FOR WESTERN UPPER MI. WILL
KEEP A DRY FCST FOR THE REMAINDER OF THE AREA.
IN THE EXTENDED /WED NIGHT-NEXT SUNDAY/...THE FULL AMPLITUDE LONG
WAVE TROUGH WILL PERSIST FROM HUDSON BAY THROUGH THE GREAT LAKES
REGION THROUGH THE PERIOD. THIS WILL KEEP THE WEATHER FAIRLY
UNSETTLED THROUGH SATURDAY. THE NUMERICAL GUIDANCE IS IN GOOD
AGREEMENT REGARDING THE LONG WAVE...BUT DIFFER SOMEWHAT ON SPECIFIC
DETAILS REGARDING INDIVIDUAL SHORT WAVES AND AS SUCH THEY DIFFER ON
EXACT POSITION OF THE LONG WAVE TROUGH. THE MAIN OUTLIER WITH THE
00Z RUN IS THE OPERATIONAL ECMWF WHICH KEEPS THE MAIN TROUGH
POSITIVLY TILTED WITH THE TROUGH AXIS FURTHER WEST. THIS IS LIKELY
DUE TO THAT MODEL ALLOWING STRONGER SHORT WAVE ENERGY TO DIVE DOWN
THE BACK SIDE OF THE UPPER TROUGH THURSDAY INTO FRIDAY. AT THIS
TIME...THIS IS NOT SUPPORTED BY THE GFS...NOR THE MAJORITY OF THE
ENSEMBLE MEMBERS FROM THE GFS AND ECMWF. WILL THEREFORE TREND THE
FORECAST TOWARD THE GFS/GEM COMPROMISE...BUT THE REALITY OF THE
MATTER IS THAT EITHER SOLUTION WOULD MAINTAIN UNSETTLED WEATHER FOR
THE AREA FOR MUCH OF THE EXTENDED. THERE WILL BE PERIODS OF DRY
WEATHER...BUT GIVEN THE UNCERTAINTY OF EXACT SHORT WAVE POSITIONS
ESPECIALLY FOR LATE INTO THE WEEK...IT WILL BE TOUGH TO PIN DOWN
SPECIFICS. WITH THAT BEING SAID...WILL NEED TO GO WITH CHANCE POPS
EACH DAY OF THE EXTENDED THROUGH SATURDAY. THE BEST CHANCE FOR RAIN
MAY BE FRIDAY INTO FRIDAY NIGHT WHERE THE GFS AND GEM BOTH AGREE ON
A WAVE MOVING ACROSS THE UPPER LAKES WITH LOW PRESSURE ACROSS THE
AREA. IN FACT...EVEN THE ECMWF SHOWS PCPN FRIDAY. BY SUNDAY...THE
GFS SUGGESTS THAT THE TROUGH WILL SLOWLY EXIT EAST OF THE
AREA...ALLOWING SOME DRYING TO MOVE IN. WILL THEREFORE GO WITH A DRY
FORECAST FOR NOW ON SUNDAY...BUT THAT IS SUBJECT TO CHANGE IF THE
TROUGH IS A LITTLE SLOWER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 109 AM EDT MON SEP 17 2012
AFTER PASSAGE OF COLD FRONT...ABUNDANT MOISTURE WILL PULL WIDESPREAD
RAIN AND CLOUDS EASTWARD ACROSS THE TAF SITES OVERNIGHT. EXPECT SOME
LOWERING OF VIS/CIGS AS A RESULT...THOUGH LATEST MODEL GUIDANCE SHOWS
A LOW LEVEL DRY AIR POCKET WHICH COULD INHIBIT SOME OF THE IFR
VIS/CIGS EXPECTED IN LAST TAF ISSUANCE. CHOSE TO KEEP SITES
MVFR...THOUGH SOME AMENDMENTS FOR EXACT TIMINGS AND CIG/VIS MAY NEED
TO BE MADE. THE EXCEPTION IS KSAW...WHICH DUE TO MOIST COLD AIRMASS
PULLING STRONG WINDS OFF THE WARM LAKE...COULD SEE HEAVIEST RAIN
SHOWERS...SO SOME IFR CONDITIONS ARE POSSIBLE. MAIN FORCING WILL
MOVE OFF TO THE EAST DURING THE AFTERNOON BRINGING RAIN TO AN END AT
KCMX. HOWEVER...COLD AIRMASS OVER WARM LAKE AND RESULTING STRONG N
WINDS WILL MAKE CONDITIONS FAVORABLE FOR LAKE EFFECT RAIN SHOWERS
/TRANSITION FROM RA TO SHRA IN TAF/ FOR KIWD AND KSAW THROUGH
REMAINDER OF TAF PERIOD. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT SUN SEP 16 2012
EXPECT RELATIVELY LIGHT WINDS UNDER 20 KTS FOR MOST OF THIS EVENING
OVER THE LAKE WITH FAIRLY HI STABILITY/A WEAK LO PRES TROF CROSSING
THE AREA. THEN EXPECT A WIND SHIFT TO THE NNW WITH THE PASSAGE OF A
STRONG COLD FRONT BY LATE EVENING OVER THE W AND THEN ON MON MORNING
OVER THE E HALF. AS COLDER AIR FOLLOWS THE FRONT OVER THE RELATIVELY
WARM WATERS OF LAKE SUPERIOR AND STABILITY DECREASES...EXPECT
STRONGER N WINDS TO 25 TO 30 KTS TO DEVELOP W TO E. BUT SINCE LATEST
GUIDANCE INDICATES THE PRES GRADIENT WILL BE WEAKER THAN EXPECTED ON
PREVIOUS SHIFTS...GALES NOW APPEAR UNLIKELY. SO THE GOING GALE WATCH
THAT WAS IN EFFECT ON MON OVER PORTIONS OF THE W HALF WAS DROPPED.
NORTH WINDS WILL PERSIST MONDAY NIGHT INTO TUESDAY BEFORE GRADUALLY
SHIFTING TO THE NW THEN W BY TUESDAY EVENING. ANOTHER LOW PRESSURE
TROUGH WILL APPROACH WED THEN PASS ACROSS THE LAKE WED NIGHT. AHEAD
OF THE TROUGH...WINDS WILL TURN SOUTHERLY AT 15-25 KT...THEN WILL
TURN W-NW BY THU MORNING. OTHER THAN SOME GUSTS CLOSE TO GALE FORCE
MONDAY EVENING...GALES ARE NOT EXPECTED AT THIS TIME THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MRD
AVIATION...JMW
MARINE...KC/MRD
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
343 AM CDT MON SEP 17 2012
.SHORT TERM...
ISSUED AT 334 AM CDT MON SEP 17 2012
(TODAY AND TONIGHT)
WHEN I WALKED IN THE DOOR AT 1000 PM LAST NIGHT I THOUGHT THE
FORECAST WAS GOING TO BE A BIT MORE CLEAR CUT THAN IT IS NOW. AREAS
OF DENSE FOG HAVE DEVELOPED OVERNIGHT...ESPECIALLY FROM ST LOUIS
NORTHWARD WHERE THERE ARE ONLY THIN HIGH CLOUDS AT THIS TIME.
MEANWHILE A PESKY AREA OF SHOWERS HAS ALSO DEVELOPED FROM SRN IL
ACROSS THE EASTERN OZARKS...APPARENTLY IN RESPONSE TO WEAK LOW
LEVEL WAA. VISIBILITIES HAVE IMPROVED SLIGHTLY IN THE ST LOUIS
AREA WITHIN THE LAST HOUR...AND THIS MAY BE DUE TO SOME THICKER
CLOUD COVER. I WILL HAVE TO MENTION SOME DENSE FOG THIS
MORNING...PROBABLY FROM I-70 NORTHWARD...BUT DONT HAVE ANY PLANS
FOR AN ADVISORY. THE PRECIPITATION TRENDS ARE A LITTLE MORE MURKY.
THE MODEL QPFS AND HRRR WANT TO KEEP A PERSIST THREAT OF SHOWERS
ACROSS THE SRN CWA THRU THE MORNING AND RAMPING UP INTO THE
AFTERNOON IN RESPONSE TO CONTINUED WAA AND LITTLE VORTS RIDING
ALONG THE NORTHERN FRINGE OF THE SHEAR AXIS THROUGH THE BOOTHEEL
REGION. MEANWHILE IT STILL LOOKS AS THOUGH THE AIR MASS ALONG AND
AHEAD OF THE ENCROACHING COLD FRONT WILL DESTABILIZE THIS
AFTERNOON AND THERE WILL BE SUFFICIENT FORCING FOR THE DEVELOPMENT
OF SCATTERED SHOWERS AND THUNDERSTORMS AND POSSIBLY A BROKEN LINE
FROM EASTERN MO INTO IL. THE POTENT NE-SW ORIENTED COLD FRONT
SHOULD BE BI-SECTING THE ST LOUIS AREA AT 00Z WITH GUSTY NORTHWEST
WINDS IN ITS WAKE AND GOOD CAA...WHILE A THREAT OF SHOWERS AND
THUNDERSTORMS WILL PERSIST ALONG AND AHEAD OF IT. THE FRONT SHOULD
CLEAR THE CWA BY MIDNIGHT ENDING THE PRECIPITATION THREAT AS
WELL...WITH CLOUDS CLEARING 3-4 HOURS BEHIND IT.
GLASS
&&
.LONG TERM...
ISSUED AT 334 AM CDT MON SEP 17 2012
(TUESDAY THROUGH SATURDAY)
WE WILL HAVE A TASTE OF FALL TUESDAY INTO WEDNESDAY MORNING WITH
WELL BELOW AVERAGE TEMPERATURES. GUSTY NORTHWEST WINDS WILL MAKE
IT FEEL EVEN COOLER ON TUESDAY. HIGH PRESSURE WILL SLIDE ACROSS
THE AREA ON TUESDAY NIGHT WITH THE CENTER OF THE HIGH NEAR THE
BOOTHEEL BY DAYBREAK WEDNESDAY. IT APPEARS THE COOLEST LOWS SHOULD
BE ACROSS THE SOUTHEAST HALF OF THE CWA AND ESPECIALLY THE EASTERN
OZARKS. SOME PATCHY FROST IS NOT OUT OF THE QUESTION IN SOME
SHELTERED SPOTS IN THE OZARKS WHERE MINS COULD FALL TO 36-38 DEGS.
LOW LEVEL WAA QUICKLY GETS UNDERWAY LATER ON WEDNESDAY MORNING AS
THE HIGH RETREATS AS SOUTHERLY FLOW KICKS IN. ANOTHER COLD FRONT
MAKES AN ATTEMPT TO MOVE THROUGH THE AREA ON THURSDAY BUT IT
WASHES OUT AS SURFACE PRESSURES BEGIN FALLING ACROSS THE PLAINS.
ANOTHER MORE FORMIDABLE COLD FRONT SHOULD MOVE THROUGH THE AREA ON
FRIDAY WITH A REINFORCING SHOT OF COOLER AIR ON ITS HEELS ABOUT
12H LATER.
GLASS
&&
.AVIATION...
ISSUED AT 1139 PM CDT SUN SEP 16 2012
MVFR TO IFR FOG AND STRATUS ARE EXPECTED TO PERSIST AT THE
TERMINALS OVERNIGHT BEFORE CONDITIONS IMPROVE WITH DIURNAL MIXING
BY MID TO LATE MORNING TOMORROW. THERE IS A CHANCE OF PCPN
TOMORROW AS A CDFNT APPROACHES AND MOVES THROUGH THE REGION
HOWEVER CONFIDENCE IN THE TIMING REMAINS LOW ATTM. SEVERAL HOURS
OF GUSTY NNWLY WINDS ARE EXPECTED SHORTLY AFTER FROPA DUE TO THE
TIGHT PRESSURE GRADIENT.
SPECIFICS FOR KSTL...MVFR TO IFR FOG AND STRATUS ARE EXPECTED TO
PERSIST OVERNIGHT BEFORE CONDITIONS IMPROVE WITH DIURNAL MIXING
BY MID TO LATE MORNING TOMORROW. THERE IS A CHANCE OF PCPN
TOMORROW AS A CDFNT APPROACHES AND MOVES THROUGH THE REGION
HOWEVER CONFIDENCE IN THE TIMING REMAINS LOW ATTM. SEVERAL HOURS
OF GUSTY NNWLY WINDS ARE EXPECTED SHORTLY AFTER FROPA DUE TO THE
TIGHT PRESSURE GRADIENT.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
345 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL SUPPLY OUR REGION WITH
ONE MORE BEAUTIFUL DAY WITH TEMPERATURES SOARING WELL ABOVE NORMAL.
CONDITIONS WILL DETERIORATE TONIGHT AS A COMPLEX STORM SYSTEM WILL
APPROACH FROM THE OHIO VALLEY. THE MOISTURE RICH SYSTEM WILL SPREAD
A SOAKING RAIN ACROSS OUR REGION LATE TONIGHT AND TUESDAY...WITH
SOME SITES PICKING UP OVER AN INCH OF RAIN. HIGH PRESSURE WILL BRING
US A CRISP FALL LIKE DAY FOR WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
IF YOU LIKED THE WEATHER ON SUNDAY...THEN YOU ARE GOING TO LOVE IT
TODAY. HIGH PRESSURE OFF THE MIDDLE ATLANTIC COAST WILL KEEP PLENTY
OF SUBSIDENCE OVER OUR REGION...AND COUPLED WITH A FAIRLY DRY
AIRMASS...WE CAN ANTICIPATE ANOTHER SUN FILLED DAY. THERE WILL BE AN
INCREASE IN HIGH LEVEL CLOUDS LATER IN THE AFTERNOON...BUT NOT
BEFORE H85 TEMPS OF 10C HELP TO BOOST OUR NEAR SFC TEMPS WELL INTO
THE 70S. IN FACT...SOME OF THE WARMER VALLEYS MAY TICKLE 80. THESE
READINGS WILL BE AT LEAST 10 DEG ABOVE NORMAL.
CLOUDS WILL THEN INCREASE AND THICKEN ACROSS OUR FORECAST AREA
DURING THE COURSE OF TONIGHT AS A VERY ENERGETIC...COMPLEX STORM
SYSTEM WILL APPROACH FROM THE OHIO VALLEY. RICH GULF MOISTURE
POOLING OVER THE SOUTHERN STATES AHEAD OF THE DEVELOPING STORM
SYSTEM WILL BE WHISKED NORTHWARDS WITHIN H85-70 WINDS OF 70-80 KTS.
THE CORE OF THESE WINDS WILL BE SOUTH OF OUR REGION TONIGHT...BUT
ARE FORECAST TO MOVE OVER EASTERN NEW YORK ON TUESDAY. THESE
EXTREMELY ANOMALOUS WINDS WILL BE AS MUCH AS 5 STANDARD DEVIATIONS
FROM NORMAL IN THEIR STRENGTH...WHICH EQUATE TO AN EVENT THAT HAS
LESS THAN ONE HALF OF A PERCENT CHANCE OF OCCURRENCE FOR THE
PARTICULAR CALENDAR DAY.
THE COMPLEX STORM SYSTEM ITSELF WILL FEATURE A WAVY FRONTAL BOUNDARY
THAT WILL EVENTUALLY INCLUDE A DEEPENING SFC LOW. THE BURGEONING LOW
WILL RIDE ALONG THE FRONT AND LIFT FROM ABOUT WEST VIRGINIA LATE
TONIGHT TO OUR FINGER LAKES ON TUESDAY. A POTENT SHORTWAVE DIVING
INTO THE BASE OF A DIGGING H5 TROUGH OVER THE UPPER MISSISSIPPI
VALLEY WILL ENERGIZE THIS SFC WAVE...WHILE A H25 JET OF 140 KTS OVER
THE UPPER GREAT LAKES WILL PLACE OUR FORECAST AREA UNDER THE
INFLUENCE OF THE JET ENTRANCE REGION. THE COMBINATION OF THE LIFT
FROM THE RR QUAD OF THE H25 JET...THE STRONG LOW LEVEL JET AND
STEADY HGT FALLS WILL PRODUCE DEEP ASCENT FOR THE MOISTURE RICH
AIRMASS. PWAT VALUES WILL INCREASE TO MORE THAN 1.5" FOR MOST SITES.
BREAKING THIS DOWN INTO A FORECAST FOR TONIGHT...RAIN SHOULD
APPROACH THE NEW YORK PENNSYLVANIA LINE AROUND MIDNIGHT...THEN
SPREAD NORTH-NORTHEAST DURING THE REMAINING OVERNIGHT HOURS. THE
RAIN SHOULD REACH THE THOUSANDS ISLAND REGION BY ABOUT DAYBREAK.
BECAUSE OF THE STRONG SOUTHERLY FLOW ALOFT...TEMPS SHOULD REMAIN
WELL ABOVE SEASONAL VALUES TONIGHT WITH LOWS ONLY FORECAST TO DROP
TO WITHIN A COUPLE DEGREES OF 60. NEAR LAKE ERIE AND OVER PARTS OF
THE IAG FRONTIER...LOWS MAY BE CLOSER TO 65. AGAIN...THESE VALUES
WILL BE 10 OR MORE DEG F ABOVE NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
VERY ACTIVE WEATHER WILL KICK OFF THIS PERIOD AS A SHARP UPPER LEVEL
TROUGH SLIDES EAST ACROSS THE GREAT LAKES REGION. AT THE SURFACE...
AN ASSOCIATED COMPLEX SURFACE LOW OVER OHIO AND SOUTHERN ONTARIO
TUESDAY MORNING WILL LIFT NORTHEAST INTO QUEBEC BY TUESDAY
EVENING...BEFORE RAPIDLY EJECTING NORTHWARD INTO LABRADOR BY
WEDNESDAY MORNING.
AS HAS BEEN PREVIOUSLY DETAILED IN THIS SPACE...THIS SYSTEM WILL BE
ACCOMPANIED BY A RICH SUPPLY OF GULF MOISTURE...WITH PRECIPITABLE
WATER VALUES RISING TO BETWEEN 1.5 AND 2 INCHES COURTESY OF THE DEEP
SOUTHWESTERLY SYNOPTIC-SCALE FLOW PRECEDING THE LOW. PLENTY OF
FORCING MECHANISMS WILL ALSO BE IN PLACE TO STRONGLY LIFT THIS
MOISTURE...INCLUDING STRONG HEIGHT FALLS AND WARM AIR ADVECTION
ALOFT...EXCELLENT LOW LEVEL CONVERGENCE IN THE VICINITY OF THE
SURFACE WAVE AND AT THE NOSE OF A DEVELOPING 70-80 KT LOW LEVEL
JET...AND STRONG UPPER LEVEL JET DYNAMICS SUPPLIED BY THE RIGHT REAR
QUAD OF A 120+ KT UPPER LEVEL JET STREAK. IT SHOULD GO WITHOUT
SAYING THAT ALL OF THIS MOISTURE AND LIFT WILL ADD UP TO A NEAR
CERTAINTY OF RAINFALL ON TUESDAY...SOME OF WHICH COULD BE HEAVY AT
TIMES. IN ADDITION...SOME WEAK ELEVATED INSTABILITY WILL ALSO BE
PRESENT ALOFT...AND THIS WILL ALSO ALLOW FOR THE POSSIBILITY OF SOME
ISOLATED EMBEDDED THUNDERSTORMS...ESPECIALLY GIVEN THE VERY STRONG
AND DYNAMIC NATURE OF THIS SYSTEM.
IN TERMS OF POTENTIAL RAINFALL AMOUNTS...THE NAM/GFS/GEM/ECMWF HAVE
ALL COME INTO BETTER AGREEMENT ON A SOMEWHAT MORE EASTERLY TRACK TO
THE SURFACE WAVE COMPARED TO 24 HOURS AGO...WITH THE MODEL CONSENSUS
THUS SUPERIMPOSING THE BEST OVERALL LIFT AND RICHEST MOISTURE...AND
CONSEQUENTLY THE GREATEST QPF...ACROSS OUR EASTERN FINGER LAKES AND
NORTH COUNTRY ZONES. IN THIS SPECIFIC REGION...A BLEND OF THE ABOVE
GUIDANCE PACKAGES SUGGEST THAT RAINFALL AMOUNTS OF 1 TO 1.5 INCHES
APPEAR POSSIBLE...WITH LOCALIZED AMOUNTS UP TO 2 INCHES NOT OUT OF
THE QUESTION. MEANWHILE FURTHER TO THE WEST...SOMEWHAT LESSER
RAINFALL AMOUNTS OF A HALF INCH TO AN INCH NOW APPEAR MORE LIKELY.
GIVEN THE VERY DRY ANTECEDENT CONDITIONS...THESE RAINFALL AMOUNTS
WILL BE UNLIKELY TO CAUSE ANY REAL FLOODING CONCERNS ACROSS LARGE
AREAS OR ALONG OUR LARGER CREEKS AND RIVERS...WITH ANY ISSUES MORE
THAN LIKELY REMAINING CONFINED TO LOCALIZED AREAS ALONG SMALLER
STREAMS AND LOW LYING/OTHER AREAS OF POOR DRAINAGE ACROSS OUR
EASTERN ZONES.
WITH ALL OF THE ABOVE IN MIND...HAVE ELECTED TO CONFINE ANY AREAS OF
POTENTIALLY HEAVY RAIN ON TUESDAY TO AREAS FROM THE GENESEE VALLEY
EASTWARD IN THE GRIDS AND WORDED FORECAST...AND WILL ALSO PULL BACK
SOMEWHAT ON THE HEAVY RAIN POTENTIAL IN THE HWO...AGAIN FOCUSING
THIS MORE ON OUR EASTERN ZONES WHERE THE HEAVIER RAINFALL IS MORE
LIKELY.
IN TERMS OF THE TIMING OF THE STEADIEST RAIN...THE ABOVE MODEL
CONSENSUS SUPPORTS A SOMEWHAT FASTER OVERALL TIMING COMPARED TO WHAT
WAS SEEN YESTERDAY...WITH THE STEADIEST AND MOST WIDESPREAD RAIN NOW
APPEARING AS IF IT WILL FALL BETWEEN MID TUESDAY MORNING AND MID
TUESDAY AFTERNOON. AFTER THAT TIME...THE STEADIEST RAINS WILL
QUICKLY TAPER OFF FROM WEST TO EAST BETWEEN LATE TUESDAY AFTERNOON
AND TUESDAY EVENING WITH THE PASSAGE OF THE TRAILING COLD FRONT...
WITH THE BACK EDGE OF THIS NOW APPEARING LIKELY TO EXIT OUR EASTERN
ZONES BETWEEN 03Z AND 06Z WEDNESDAY.
IN THE WAKE OF THE TRAILING COLD FRONT...A WEST-NORTHWESTERLY FLOW
OF MUCH COOLER AIR WILL FLOOD ACROSS THE REGION LATER TUESDAY AND
TUESDAY NIGHT...WITH 850 MB TEMPS PLUNGING TO BETWEEN 0C AND +3C BY
WEDNESDAY MORNING...THEN REMAINING AT THESE LEVELS RIGHT THROUGH
WEDNESDAY. WITH LAKE SURFACE TEMPS STILL RUNNING AROUND 21C...THIS
WILL BE PLENTY COLD ENOUGH TO SET OFF A LAKE RESPONSE...HOWEVER
MOISTURE WILL ONCE AGAIN BE A BIG LIMITING FACTOR THANKS TO
PLENTIFUL DRY AIR AND SUBSIDENCE ADVECTING IN BEHIND THE DEPARTING
LOW/COLD FRONT. WITH THE BULK OF ANY MOISTURE CONFINED TO 5-6 KFT OR
BELOW...WILL ONLY INDICATE SOME LINGERING LOWER-END CHANCE POPS
EAST-SOUTHEAST OF THE LAKES TUESDAY NIGHT...WITH ANY SCATTERED LAKE
EFFECT RAIN SHOWERS THEN FALLING APART ALTOGETHER ON WEDNESDAY WITH
DIURNAL INFLUENCES...AND AS HIGH PRESSURE BUILDS DIRECTLY OVERHEAD
ALONG WITH FURTHER DRYING AND INCREASING SUBSIDENCE. AFTER
THAT...DRY AND QUIET WEATHER IS EXPECTED TO CONTINUE THROUGH
WEDNESDAY NIGHT WITH THE AXIS OF THE AFOREMENTIONED SURFACE RIDGE
REMAINING PARKED DIRECTLY OVERHEAD.
WITH REGARD TO TEMPERATURES...FOLLOWING HIGHS IN THE MID 60S TO
LOWER 70S ON TUESDAY...EXPECT A SHARP COOLDOWN FOR THE REMAINDER
OF THE PERIOD GIVEN THE STRONG COLD AIR ADVECTION PATTERN BEHIND
THE DEPARTING LOW. EXPECT LOWS TO FALL BACK TO THE MID TO UPPER
40S TUESDAY NIGHT...WITH DAYTIME HIGHS ON WEDNESDAY THEN BARELY
REACHING 60 OR SO ACROSS THE LOWER ELEVATIONS...AND LIKELY NOT
MAKING IT OUT OF THE UPPER 50S ACROSS THE HIGHER TERRAIN. EVEN
COOLER READINGS IN THE LOWER TO MID 40S WILL THEN FOLLOW FOR
WEDNESDAY NIGHT...WITH UPPER 30S FOUND ACROSS INTERIOR PORTIONS OF
THE SOUTHERN TIER AND NORTH COUNTRY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE FIRST HALF OF THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A
LINGERING BROAD/FLAT TROUGH OVER EASTERN NORTH AMERICA RELOADING TO
OUR WEST...AS ANOTHER STRONG SHORTWAVE TROUGH PLUNGES SOUTHEASTWARD
ACROSS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. OUT AHEAD OF
THIS SHORTWAVE...THE PREVAILING SYNOPTIC-SCALE FLOW WILL AGAIN TURN
SOUTHWESTERLY...AND THIS WILL HELP TO TRANSPORT MUCH WARMER AIR BACK
INTO OUR REGION FOR A COUPLE OF DAYS. A BLEND OF THE 00Z GFS AND
ECMWF SUGGESTS 850 MB TEMPS RECOVERING TO BETWEEN +5C AND +8C
THURSDAY AND TO AROUND +11C/+12C FRIDAY...WHICH SHOULD BE ENOUGH TO
BOOST HIGH TEMPS BACK INTO THE 65-70 DEGREE RANGE ON THURSDAY...AND
AT LEAST THE LOWER TO MID 70S ON FRIDAY. THUS...WEDNESDAY`S SHARP
COOLDOWN WILL BE VERY BRIEF...WITH TEMPERATURES RECOVERING TO A BIT
ABOVE NORMAL LEVELS BY THE END OF THE WORK WEEK.
IN TERMS OF PRECIPITATION CHANCES...THE GFS AND ECMWF ARE NOW IN
BETTER AGREEMENT THAT THE VAST MAJORITY OF THE THURSDAY-FRIDAY TIME
FRAME SHOULD REMAIN DRY. BOTH MODELS WEAKEN AN INITIAL LEAD COLD
FRONT AS IT TRIES TO PRESS TOWARD OUR AREA ON THURSDAY...WITH THIS
FEATURE EVENTUALLY FALLING APART OVER SOUTHERN ONTARIO LATE THURSDAY
AND THURSDAY NIGHT. BOTH PACKAGES ALSO ARE NOW IN BETTER AGREEMENT
ON THE EVOLUTION OF A SUBSEQUENT SURFACE WAVE AND ASSOCIATED
STRONGER COLD FRONT...WITH THIS LATTER FEATURE ONLY APPROACHING
FAR WESTERN NEW YORK BY LATE FRIDAY AFTERNOON/FRIDAY EVENING. WITH
THE ABOVE IN MIND...HAVE KEPT PRECIP CHANCES FOR BOTH DAYS LARGELY
CONFINED TO SLIGHT CHANCE OR LESS...WITH ONLY SOME LOW CHANCE POPS
INDICATED ACROSS FAR WESTERN NEW YORK LATER FRIDAY AFTERNOON.
AFTER THAT...BOTH GUIDANCE PACKAGES DIG THE LARGE-SCALE UPPER TROUGH
DEEPER INTO THE CENTRAL AND EASTERN GREAT LAKES NEXT WEEKEND...WITH
THE AFOREMENTIONED SECOND COLD FRONT SLOWLY PUSHING ACROSS THE AREA
BETWEEN FRIDAY NIGHT AND SATURDAY...FOLLOWED BY A SECONDARY AND
WEAKER AREA OF LOW PRESSURE PASSING BY TO OUR NORTH ON SUNDAY. AT
THIS DISTANT JUNCTURE...THIS EVOLUTION IN THE PATTERN WILL SUPPORT
SOME BROADBRUSH LOWER-END SHOWER CHANCES BOTH DAYS...ALONG WITH A
TREND TOWARD PROGRESSIVELY COOLER TEMPERATURES AS THE COLD POOL
ASSOCIATED WITH THE UPPER LOW OVERSPREADS OUR REGION.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE CENTERED ALONG THE MID ATLANTIC COAST WILL KEEP FAIR
VFR WEATHER IN PLACE OVER OUR REGION THROUGH TODAY...ALTHOUGH THERE
COULD BE A FEW HOURS OF MVFR VSBYS IN EARLY MORNING FOG FOR SITES
SUCH AS KJHW AND KELZ.
DURING THE COURSE OF TONIGHT THOUGH...A COMPLEX STORM SYSTEM
WILL DEVELOP OVER THE UPPER OHIO VALLEY AND SPREAD RAIN AND
GENERALLY DETERIORATING CONDITIONS NORTHWARDS. IFR CONDITIONS SHOULD
BE FOUND OVER THE WESTERN SOUTHERN TIER WITH MVFR VSBYS/CIGS
POSSIBLE FOR THE REMAINDER OF THE WRN COUNTIES.
OUTLOOK...
TUESDAY AND TUESDAY NIGHT...MVFR/IFR WITH RAIN. LLWS.
WEDNESDAY...IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
&&
.MARINE...
WHILE HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST SHOULD
KEEP CONDITIONS BELOW SMALL CRAFT ADVISORY CRITERIA TODAY...WATERS
WILL BE QUITE CHOPPY ACROSS THE EASTERN PART OF LAKE ONTARIO THIS
MORNING AND THEN OVER PARTS OF LAKE ERIE DURING THE MIDDAY AND EARLY
AFTERNOON. IN THOSE AREAS...MODERATE SOUTHERLIES WILL PRODUCE WAVES
OF 2 TO 4 FEET SO THEY WILL HAVE TO BE CLOSELY WATCHED.
WINDS AND WAVES WILL BRIEFLY SUBSIDE ON BOTH LAKES THIS EVENING...
THEN A COMPLEX STORM SYSTEM WILL APPROACH THE LOWER GREAT LAKES
DURING THE OVERNIGHT. WINDS AHEAD OF THIS STORM SYSTEM WILL FRESHEN
OVER EASTERN LAKE ONTARIO LATER TONIGHT...POSSIBLY PRODUCING SCA
CONDITIONS BY DAYBREAK TUESDAY.
STRONGER WINDS ARE EXPECTED IN THE WAKE OF THE STORM SYSTEM TUESDAY
AFTERNOON AND NIGHT WITH FRESH WEST TO NORTHWEST BREEZES PRODUCING
SCA CONDITIONS ACROSS MUCH OF LAKE ONTARIO AND POSSIBLY FOR A SHORT
TIME...ON LAKE ERIE.
HIGH PRESSURE WILL MOVE IN ON WEDNESDAY TO PROMOTE WEAKER WINDS AND
LOWER WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...RSH
MARINE...RSH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
527 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL DRIFT OFF THE CAROLINA COASTS TODAY AS A COLD
FRONT APPROACHES FROM THE WEST. LOW PRESSURE WILL MOVE THROUGH THE
WESTERN CAROLINAS TUESDAY...DRAGGING A STRONG COLD FRONT ACROSS
THE AREA. THIS COLD FRONT WILL PRODUCE WIDESPREAD SHOWERS AND
THUNDERSTORMS...SOME OF WHICH COULD BE STRONG. COLD FRONT WILL
LINGER NEAR THE COAST WEDNESDAY...BEFORE HIGH PRESSURE BRINGS
COOLER AND DRIER WEATHER INTO THE AREA FOR LATE WEEK AND THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 440 AM MONDAY...SFC WIND FIELD VIA LATEST HRRR INDICATES A
SFC BOUNDARY LYING ACROSS THE FA THIS MORNING...WHICH SHOULD
TRANSITION INTO A WARM FRONT AND LIFT NORTH OF THE FA BY MIDDAY
THROUGH THIS AFTERNOON. THE BEST SYNOPTIC LIFT UVVS WILL LIE ALONG
AND NORTH OF THIS FRONT...MUCH OF IT FROM WEAK MID-LEVEL S/W
TROFS/IMPULSES MOVING EASTWARD ACROSS THE NORTHERN HALF OF NC.
HAVE ADJUSTED THE HIER POPS MAINLY ALONG AND NORTH OF THE ILM NC-
SC BORDER FOR TODAY. VIA VARIOUS MODEL TIME HEIGHT SECTIONS ACROSS
THE FA...MID AND HIGH LEVEL CLOUDS WILL BLANKET MUCH OF THE AREA
TODAY. THIS IN TURN WILL BLOCK A GOOD AMOUNT OF THE DAYS
INSOLATION...RESULTING WITH BORDERLINE WEAK INSTABILITY FOR
CONVECTION.
FOR TONIGHT...THE MID AND UPPER LEVEL RIDGE AXIS MOVES OFF THE
COAST ALLOWING THE MID LEVEL S/W TROF ALONG THE US NW GULF COAST
TO TRACK EASTWARD...AND BEGIN TO PHASE WITH THE EXPANDING AND
DEEPENING HUDSON BAY/GREAT LAKES MID-UPPER LEVEL TROF. EARLY THIS
EVENING...SFC THRU 8H FLOW WILL HAVE TAPPED BOTH ATLANTIC AND GULF
OF MEXICO MOISTURE. AFTER MIDNIGHT...FLOW ABOVE 7H WILL HAVE
FURTHER TAPPED GULF OF MEXICO AND EVENTUALLY ATLANTIC MOISTURE
BY DAYBREAK. LOOK FOR MODEL PROGGED SOUNDING PWS TO EASILY
SURPASS 2.00 INCHES. WILL INDICATE INCREASING POPS DURING
TONIGHT...WITH HEAVY RAIN POSSIBLE FROM ANY CONVECTION. LOOK FOR A
SOMEWHAT FAVORABLE LOW LEVEL HODOGRAPH FOR ROTATING THUNDERSTORMS
BETWEEN MIDNIGHT TONIGHT AND UP TO SEVERAL HRS AFTER DAYBREAK
TUESDAY. ISOLATED CONVECTION THAT MOVES ONSHORE LATE TONIGHT WILL
BE THE ACTIVITY SUSCEPTIBLE TO PRODUCE THE ISOLATED WATERSPOUT/TORNADO
... AS WELL AS DAMAGING WIND GUSTS. HAVE PLACED ITS REMOTE POSSIBILITY
WITHIN THE HWO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG COLD FRONT STILL PROGGED TO CROSS THE
AREA TUESDAY BRINGING WIDESPREAD SHOWERS/TSTMS...POTENTIALLY WITH
DAMAGING WINDS AND HEAVY RAIN TO THE AREA...IN AN EARLY SEASON
HIGH SHEAR LOW CAPE EVENT.
PHASING OCCURRING AT 500MB TUESDAY BETWEEN SOUTHERN AND NORTHERN
STREAM IMPULSES CREATES A HIGHLY AMPLIFIED TROUGH ACROSS THE EASTERN
CONUS. SURFACE LOW RIDES UP THE APPALACHIANS AND DRIVES A COLD ACROSS
THE CAROLINAS. STRONG LOW LEVEL WINDS...APPROACHING 50 KTS AT
850MB...ADVECT COPIOUS MOISTURE INTO THE COLUMN AND STRONG MID-LEVEL
THETA-E ADVECTION OCCURS AHEAD OF THIS FRONT. SPC HAS PLACED THE
ENTIRE AREA IN A SLIGHT RISK FOR TUESDAY...30% PROBABILITIES ACROSS
THE I-95 COUNTIES...AND THIS SEEMS WARRANTED BASED OFF THE STRONG
LOW LEVEL WIND FIELDS.
DO NOT EXPECT WIDESPREAD SEVERE WINDS TUESDAY...BUT ISOLATED TO
POTENTIALLY SCATTERED DAMAGING WIND GUSTS ARE POSSIBLE. 0-6KM BULK
SHEAR RISES TO AROUND 30 KTS WHICH COULD SUPPORT MULTICELL CLUSTERS
WITH STRONG WINDS IN A UNIDIRECTIONAL SHEAR ENVIRONMENT...AND
FORECAST SBCAPE RISES TO AROUND 1000 J/KG AHEAD OF THE FRONT.
HOWEVER...DCAPE IS MINIMAL...UPPER FORCING LAGS BEHIND THE BEST
SURFACE DYNAMICS...AND FRONT ITSELF WILL CROSS DURING THE NIGHTTIME
HOURS...ALTHOUGH WITH STRONG THETA-E ADVECTION OCCURRING RIGHT UP
UNTIL FROPA...CONVECTION MAY SUSTAIN ITSELF WELL PAST NIGHTFALL.
SO...CANNOT RULE OUT A FEW DAMAGING WIND GUSTS...ESPECIALLY SINCE
SUSTAINED GRADIENT WINDS WILL LIKELY BE AROUND 20 MPH TO BEGIN
WITH...AND IT WILL NOT TAKE AN INCREDIBLY STRONG STORM TO MIX DOWN
THE LLJ WINDS. STILL...DO NOT ANTICIPATE A WIDESPREAD SEVERE WEATHER
EVENT IN THE ILM CWA...SINCE BEST COMBINATION OF FORCING SHOULD BE
DISPLACED NW OF THIS AREA. HEAVY RAIN ON THE OTHER HAND WILL BE THE
MORE SIGNIFICANT THREAT...WITH TORRENTIAL RAINFALL LIKELY IN
CONVECTION.
FRONT CROSSES THE AREA VERY EARLY WEDNESDAY...BUT INDICATIONS ARE
NOW THAT IT WILL HANG BACK NEAR THE COAST AS A SECONDARY LOW
DEVELOPS ACROSS THE SOUTHEAST AND UPPER TROUGHING LAGS BEHIND. THIS
WILL KEEP PRECIP CHANCES THROUGHOUT THE SHORT TERM...ALTHOUGH MUCH
LIGHTER QPF EXPECTED WEDNESDAY...HIGHEST NEAR THE COAST.
FORECAST PROFILES SUGGEST A WEAK WEDGE SCENARIO (RARE FOR THIS EARLY
IN THE SEASON) DEVELOPING WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES
DOWN THE COAST WHILE SW FLOW REMAINS ABOVE 900MB. THIS SUGGESTS SOME
LIGHT RAIN OR EVEN DRIZZLE POTENTIALLY PERSISTING THROUGH THE END OF
THE PERIOD. VERY DRY AIR ABOVE THE WEDGE...PLUS THIS BEING OUT OF
SEASON...MEANS THAT ONLY SCHC POP WILL BE CONTINUED THROUGH THE END
OF THE SHORT TERM BUT CLOUD COVER SHOULD BE PRETTY
SIGNIFICANT...ESPECIALLY NEAR THE COAST.
HIGH TEMPS TUESDAY WILL BE RIGHT AROUND CLIMO...LOW 80S...AS STRONG
WAA IS COUNTERACTED BY CLOUD COVER AND SHOWERS...WHILE NIGHTTIME
MINS WILL BE HELD WELL ABOVE NORMAL...ONLY FALLING TO THE UPPER
60S/LOW 70S. WEDNESDAY WILL BE COOLER BEHIND THE FRONT...AROUND 80
FOR HIGHS AND NEAR 60 FOR LOWS AWAY FROM THE IMMEDIATE COAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...FRONT HOVERING JUST OFFSHORE MAY ALLOW FOR
CONTINUED SHOWERS NEAR THE COAST ON THURSDAY. FORECAST PROFILES DRY
OUT CONSIDERABLY HOWEVER...AND WILL DROP INHERITED CHC TO JUST SCHC
ON THE COAST...SILENT INLAND. BEST CHANCE WILL BE DURING THE EARLY
PART OF THE DAY BEFORE HIGH PRESSURE MORE FIRMLY RIDGES DOWN THE
COAST FORCING THE FRONT FURTHER OFFSHORE. OTHERWISE...THE EXTENDED
FEATURES DRY AND SEASONABLE WEATHER AS HIGH PRESSURE DOMINATES AT
THE SURFACE AND A LARGE UPPER TROUGH PERSISTS OVER THE EASTERN HALF
OF THE COUNTRY. ONLY FEATURE OF INTEREST IS A COLD FRONT WHICH WILL
TRY TO CROSS INTO THE AREA ON SATURDAY. WITH UPPER TROUGH RELOADING
ACROSS THE GREAT LAKES...MID LEVEL WINDS WILL REMAIN OUT OF THE WSW
WHICH WILL INHIBIT THIS FRONT FROM MAKING ANY NOTICEABLE IMPACT TO
THIS AREA...AND ANY COOLER AIR AND/OR PRECIP WILL BE DISPLACED NORTH
OF THE CWA.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...PERIODS OF MVFR/IFR OVERNIGHT AND INTO THE EARLY MORNING
HOURS WITH VCSH/SCATTERED SHRA AND POTENTIAL BR/LOW CIGS INLAND.
FOR SEVERAL HRS AFTER DAYBREAK...EXPECT VFR/MVFR WITH BRIEF
PERIODS OF IFR DUE TO SHRA/BR. FOR THE AFTERNOON/EVENING VFR WITH
BRIEF PERIODS OF MVFR/IFR FROM CONVECTION.
SHRA AND VCSH WILL CONTINUE THROUGH THE OVERNIGHT HOURS THROUGH
MID-MORNING. LOOKING AT NE-E LIGHT WINDS OVERNIGHT WITH THE BEST
CHANCE FOR LOW CEILINGS/FOG ACROSS THE INLAND SITES BEFORE
SUNRISE. AFTER DAYBREAK...LINGERING MVFR/IFR FOG WILL DISSIPATE
AND CIGS WILL LIFT GIVING WAY TO VFR. LOW TO MID SCT/BKN CLOUDS
WILL CONTINUE THROUGHOUT THE DAY WITH A CHANCE FOR MVFR FROM
SHRA/TSRA ACROSS THE AREA. EAST-SOUTHEAST WINDS WILL INCREASE TO
AOB 10 KTS BY THE AFTERNOON HOURS...BECOMING SOUTHERLY ALONG THE
COAST WITH GUSTS 15 TO 20 KTS. INTO THE EVENING HOURS...SHRA/TSRA
WILL GRADUALLY QUIET DOWN...EXCEPT FOR CONVECTIVE ACTIVITY OFF THE
ATL WATERS THAT COULD MOVE ONSHORE BY MIDNIGHT DUE TO A DEEPER
ONSHORE FLOW MATERIALIZING. SOUTHERLY WINDS TO INCREASE TO
SUSTAINED 10 KT BY MIDNIGHT...ESPECIALLY AT THE COASTAL TERMS.
THE EXTENDED OUTLOOK...SHRA/TSRA ON TUESDAY WITH MODERATE
CONFIDENCE FOR INTERMITTENT IFR CONDITIONS. CONVECTION WILL
CONTINUE INTO WEDNESDAY WITH IMPROVING CONDITIONS THURSDAY INTO
SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM MONDAY...SCA RAISED FOR ALL ILM WATERS FOR LATE
TONIGHT. SE-S WINDS 10 KT...WILL BECOME SOUTHERLY 10-15 KT BY THIS
AFTERNOON...AND FURTHER INCREASE TO 15 TO 20 KT TONIGHT. THIS IN
RESPONSE TO AN ORGANIZING SFC PRESSURE PATTERN...AND INCREASING
GRADIENT DEVELOPING AHEAD OF THE APPROACH OF A SURFACE COLD FRONT
FROM THE WEST. SIGNIFICANT SEAS WILL INITIALLY COMMENCE AT 2 TO
4 FT...MAINLY COMPRISED OF A 10-12 SECOND SE SWELL. WITH
INCREASING WINDS LATER TODAY AND TONIGHT...LOCALLY PRODUCED WIND
DRIVEN WAVES AT 4 TO 7 SECOND AVERAGE PERIODS WILL BECOME MORE
DOMINANT. AT THIS POINT...SWAN ADVERTIZES SIG. SEAS REACHING 4 TO
6 FT ACROSS ALL WATERS JUST PRIOR TO DAYBREAK TUE...HENCE THE
RAISING OF A SCA. WIND FIELDS JUST OFF THE DECK ARE PROGGED TO
REACH 40 KT AFTER MIDNIGHT TONIGHT. AS A RESULT...CONVECTION THAT
TRAVERSES THE ILM WATERS WILL TAP INTO THESE HIER WINDS AND
POTENTIALLY DROP THEM TO THE OCEAN SFC AS WIND GUSTS 35 KT OR
GREATER. FAVORABLE LOW LEVEL WIND SHEAR AND HODOGRAPH WILL AID
ISOLATED WATERSPOUT POSSIBILITIES...MAINLY BETWEEN MIDNIGHT AND UP
TO SEVERAL HOURS AFTER DAYBREAK TUE.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG SOUTHERLY WINDS AHEAD OF A POTENT COLD
FRONT WILL CREATE SMALL CRAFT ADVISORY CONDITIONS THROUGH MUCH OF
TUESDAY. WINDS OF 15-25 KTS WILL HELP BUILD SEAS TO 4-6 FT...HIGHEST
ACROSS THE NORTHERN WATERS. WAVES WILL BE FORMED BY A COMBINATION OF
A WEAK SE SWELL AND THE MORE DOMINANT 6 SEC SOUTHERLY WIND
WAVES...SO EXPECT RELATIVELY STEEP WAVE FACES THROUGH THE DAY.
ADDITIONALLY...STRONG THUNDERSTORMS ARE POSSIBLE AHEAD OF THE COLD
FRONT AS IT ADVANCES EASTWARD THROUGH THE EVENING. THESE STORMS
COULD PRODUCE MUCH STRONGER WIND GUSTS AND TORRENTIAL RAINFALL...AS
WELL AS LOCALLY ENHANCED WAVE HEIGHTS.
WINDS TURN WESTERLY EARLY WEDNESDAY WITH THE FRONT AND THEN BECOME
LIGHT AND VARIABLE AS THE BOUNDARY WAVERS OVER THE COASTAL WATERS.
BY LATE WEDNESDAY WINDS WILL BECOME NE...BUT REMAIN LESS THAN 10
KTS. SEAS FALL QUICKLY DURING THE DAY...FROM 3-5 FT EARLY TO 2-3 FT
LATE...THANKS TO THE EASING WIND SPEEDS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...HIGH PRESSURE RIDGES DOWN THE COAST THURSDAY
BEFORE DRIFTING OFFSHORE FRIDAY. NE WINDS OF AROUND 10 KTS PERSIST
MUCH OF THURSDAY BEFORE THE GRADIENT RELAXES...ALLOWING WINDS TO
BECOME LIGHT AND VARIABLE FRIDAY...BEFORE FINALLY TURNING TO THE SE
AT THE END OF THE PERIOD. WAVE GUIDANCE SHOWS SEVERAL DIFFERENT WAVE
GROUPS PRESENT IN THE SPECTRUM THROUGH THE EXTENDED...WITH NO GROUP
BECOMING DOMINANT. WITHOUT ANY MEANINGFUL SWELL OR PRESSURE
GRADIENT...SEAS WILL BE 1-3 FT THURSDAY...AND ONLY 1-2 FT ON FRIDAY.
&&
.TIDES/COASTAL FLOODING...
AS OF 350 AM MONDAY...BETWEEN 10 AM AND NOON TODAY...PROGGED MDL
WILMINGTON TIDE GAGE FORECASTS INDICATE A THREAT FOR GAGE READINGS
ABOVE THE 5.50 FT MLLW COASTAL FLOOD ADVISORY THRESHOLD BETWEEN 10
AM AND NOON TODAY. A PEAK OF 5.60 FT MLLW IS FORECAST AROUND 11
AM. THE PRONE LOCATIONS TO THIS TYPE OF SHALLOW FLOODING WILL
INCLUDE AREAS BORDERING ALONG THE CAPE FEAR RIVER SUCH AS WATER
STREET OF DOWNTOWN WILMINGTON... ROADWAYS LEADING TO AND FROM THE
USS NORTH CAROLINA BATTLESHIP... AND CANAL ROAD IN CAROLINA BEACH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 10 AM THIS MORNING TO NOON EDT
TODAY FOR NCZ107-108.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 5 AM EDT WEDNESDAY
FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DCH
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DCH/SGL
TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS NORMAN OK
1227 AM CDT MON SEP 17 2012
.AVIATION...
SKIES HAVE CLEARED ACROSS THE WEST WITH SOME MID/HIGH CLOUDS
LINGERING OVER EASTERN SITES. NAM AND HRRR SHOWING SOME DEVELOPMENT
OF LOW CLOUDS OVERNIGHT. GIVEN THAT LOW LEVELS REMAIN RELATIVELY
MOIST AND WITH A LIGHT SOUTHERLY FLOW EXPECTED TO CONTINUE WILL GO
WITH REDEVELOPMENT OF MVFR/IFR CIGS LATER TONIGHT. CLOUDS SHOULD
SCATTER OUT DURING THE MORNING GIVING WAY TO VFR CONDITIONS BY
MIDDAY. COLD FRONT IS EXPECTED TO MOVE ACROSS THE AREA DURING THE
DAY MONDAY SHIFTING WINDS BACK TO THE NORTH.
&&
.PREV DISCUSSION... /ISSUED 1015 PM CDT SUN SEP 16 2012/
.UPDATE...
NO SIGNIFICANT CHANGES TO THE FORECAST... ALTHOUGH HAVE UPDATED
THE CLOUD COVER SOMEWHAT. THE CURRENT OVERCAST IS ONLY SLOWLY
MOVING EAST. HRRR AND SOME OF THE NEW MOS GUIDANCE IS SUGGESTING
THAT STRATUS WILL REDEVELOP OVERNIGHT... MAINLY IN THE SOUTHEAST
THIRD OR SO OF THE AREA... BUT ALSO ACROSS THE WEST WHERE SKIES
ARE CURRENTLY CLEAR. IT REMAINS TO BE SEEN HOW WIDESPREAD IT WILL
BECOME... BUT WITH RELATIVELY LOW DEWPOINT DEPRESSIONS AND SOME
LOW-LEVEL MOISTURE ADVECTION WITH THE SOUTH WINDS... DO BELIEVE
THAT WE WILL SEE SOME STRATUS.
&&
.PREV DISCUSSION... /ISSUED 620 PM CDT SUN SEP 16 2012/
AVIATION...
MID/HIGH CLOUDS OVER EASTERN PART OF THE AREA SHOULD CONTINUE TO
GRADUALLY CLEAR FROM THE NW. COULD BE SOME PATCHY MVFR CONDITIONS
OVERNIGHT...MAINLY EAST BUT VFR CONDITIONS EXPECTED AREAWIDE BY
MONDAY MORNING. FRONT EXPECTED TO MOVE INTO NW OK MONDAY MORNING
AND THE PROGRESS THROUGH MOST SITES BY THE END OF THE PERIOD.
PRECIP CHANCES WITH THE FRONT TOO LOW TO INCLUDE IN TAFS ATTM.
PREV DISCUSSION... /ISSUED 224 PM CDT SUN SEP 16 2012/
DISCUSSION...
STILL DEALING WITH SLOW MOVING TROUGH ACROSS THE SOUTHERN PLAINS
AND TEXAS AND ASSOCIATED CLOUD COVER AND LIGHT RAIN ACROSS
SOUTHEAST OKLAHOMA. WILL KEEP SOME LOW POPS ACROSS THE SOUTHEAST
TONIGHT. MAY SEE SOME PATCHY FOG AGAIN LATE TONIGHT ACROSS PARTS
OF CENTRAL AND SOUTHEAST SECTIONS OF OKLAHOMA... BUT FOR NOW WILL
LEAVE OUT OF THE FORECAST.
MOST AREAS SHOULD SEE SUN ON MONDAY WITH WARMER TEMPS AHEAD OF
COLD FRONT WHICH WILL ENTER NORTHEAST OKLAHOMA BY LATE
MORNING/MIDDAY AND THEN MOVE QUICKLY SOUTH INTO NORTH TEXAS DURING
THE AFTN. CONT TO SEE VERY WEAK CONVERGENCE ALONG THIS FRONT...
HOWEVER MODELS STILL SHOW MODEST INSTABILITY AND MID-LEVEL LAPSE
RATES TO INITIATE STORMS. ALTHOUGH STILL APPEARS CHANCES WILL
REMAIN RATHER LOW WILL KEEP LOW POPS MONDAY AFTN AND MONDAY NIGHT
ON OUTSIDE CHANCE OF A STORM OR TWO ALONG AND BEHIND FRONT.
MILD MIDDLE OF THE WEEK WITH WARMING TREND BY LATE IN THE WEEK.
SOUTHERN PLAINS REMAIN IN NORTHWEST FLOW THROUGH NEXT WEEKEND.
HOWEVER MEDIUM RANGE MODELS CONT TO DISAGREE ON TIMING AND
STRENGTH OF SFC BOUNDARIES LATE THIS WEEK INTO NEXT WEEKEND. WILL
NOT MAKE ANY MAJOR CHANGES TO LATTER PART OF FORECAST AT THIS TIME
AS CONFIDENCE IN ANY PARTICULAR SCENARIO IS NOT HIGH. ESPECIALLY
WITH REGARDS TO PRECIP CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 60 85 53 77 / 0 20 20 0
HOBART OK 58 86 52 76 / 0 20 20 0
WICHITA FALLS TX 61 88 57 80 / 0 10 20 10
GAGE OK 52 82 46 78 / 0 10 10 0
PONCA CITY OK 59 80 49 75 / 0 20 10 0
DURANT OK 63 85 58 78 / 20 10 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
652 AM CDT MON SEP 17 2012
.SHORT TERM...
ISSUED AT 334 AM CDT MON SEP 17 2012
(TODAY AND TONIGHT)
WHEN I WALKED IN THE DOOR AT 1000 PM LAST NIGHT I THOUGHT THE
FORECAST WAS GOING TO BE A BIT MORE CLEAR CUT THAN IT IS NOW. AREAS
OF DENSE FOG HAVE DEVELOPED OVERNIGHT...ESPECIALLY FROM ST LOUIS
NORTHWARD WHERE THERE ARE ONLY THIN HIGH CLOUDS AT THIS TIME.
MEANWHILE A PESKY AREA OF SHOWERS HAS ALSO DEVELOPED FROM SRN IL
ACROSS THE EASTERN OZARKS...APPARENTLY IN RESPONSE TO WEAK LOW
LEVEL WAA. VISIBILITIES HAVE IMPROVED SLIGHTLY IN THE ST LOUIS
AREA WITHIN THE LAST HOUR...AND THIS MAY BE DUE TO SOME THICKER
CLOUD COVER. I WILL HAVE TO MENTION SOME DENSE FOG THIS
MORNING...PROBABLY FROM I-70 NORTHWARD...BUT DONT HAVE ANY PLANS
FOR AN ADVISORY. THE PRECIPITATION TRENDS ARE A LITTLE MORE MURKY.
THE MODEL QPFS AND HRRR WANT TO KEEP A PERSIST THREAT OF SHOWERS
ACROSS THE SRN CWA THRU THE MORNING AND RAMPING UP INTO THE
AFTERNOON IN RESPONSE TO CONTINUED WAA AND LITTLE VORTS RIDING
ALONG THE NORTHERN FRINGE OF THE SHEAR AXIS THROUGH THE BOOTHEEL
REGION. MEANWHILE IT STILL LOOKS AS THOUGH THE AIR MASS ALONG AND
AHEAD OF THE ENCROACHING COLD FRONT WILL DESTABILIZE THIS
AFTERNOON AND THERE WILL BE SUFFICIENT FORCING FOR THE DEVELOPMENT
OF SCATTERED SHOWERS AND THUNDERSTORMS AND POSSIBLY A BROKEN LINE
FROM EASTERN MO INTO IL. THE POTENT NE-SW ORIENTED COLD FRONT
SHOULD BE BI-SECTING THE ST LOUIS AREA AT 00Z WITH GUSTY NORTHWEST
WINDS IN ITS WAKE AND GOOD CAA...WHILE A THREAT OF SHOWERS AND
THUNDERSTORMS WILL PERSIST ALONG AND AHEAD OF IT. THE FRONT SHOULD
CLEAR THE CWA BY MIDNIGHT ENDING THE PRECIPITATION THREAT AS
WELL...WITH CLOUDS CLEARING 3-4 HOURS BEHIND IT.
GLASS
&&
.LONG TERM...
ISSUED AT 334 AM CDT MON SEP 17 2012
(TUESDAY THROUGH SATURDAY)
WE WILL HAVE A TASTE OF FALL TUESDAY INTO WEDNESDAY MORNING WITH
WELL BELOW AVERAGE TEMPERATURES. GUSTY NORTHWEST WINDS WILL MAKE
IT FEEL EVEN COOLER ON TUESDAY. HIGH PRESSURE WILL SLIDE ACROSS
THE AREA ON TUESDAY NIGHT WITH THE CENTER OF THE HIGH NEAR THE
BOOTHEEL BY DAYBREAK WEDNESDAY. IT APPEARS THE COOLEST LOWS SHOULD
BE ACROSS THE SOUTHEAST HALF OF THE CWA AND ESPECIALLY THE EASTERN
OZARKS. SOME PATCHY FROST IS NOT OUT OF THE QUESTION IN SOME
SHELTERED SPOTS IN THE OZARKS WHERE MINS COULD FALL TO 36-38 DEGS.
LOW LEVEL WAA QUICKLY GETS UNDERWAY LATER ON WEDNESDAY MORNING AS
THE HIGH RETREATS AS SOUTHERLY FLOW KICKS IN. ANOTHER COLD FRONT
MAKES AN ATTEMPT TO MOVE THROUGH THE AREA ON THURSDAY BUT IT
WASHES OUT AS SURFACE PRESSURES BEGIN FALLING ACROSS THE PLAINS.
ANOTHER MORE FORMIDABLE COLD FRONT SHOULD MOVE THROUGH THE AREA ON
FRIDAY WITH A REINFORCING SHOT OF COOLER AIR ON ITS HEELS ABOUT
12H LATER.
GLASS
&&
.AVIATION...
ISSUED AT 630 AM CDT MON SEP 17 2012
COMPLEX FORECAST IN STORE FOR THE NEXT 12 TO 18 HOURS. AREA OF
FG/ST SHUD CONTINUE TO MOVE N THIS MORNING WITH FG GRADUALLY
MOVING OUT OF THE REGION AND REPLACED BY ST. CIGS SHUD LIFT THRU
THE MORNING...BUT MAY BE SLOW TO LIFT UNTIL THIS AFTERNOON. EXPECT
TSRA TO DEVELOP TODAY WITH THE BEST CHANCES THIS AFTERNOON.
HOWEVER...WITH A WEAK CAP IN PLACE...SCT TSRA MAY DEVELOP LATE
THIS MORNING AHEAD OF THE APPROACHING CDFNT. BEHIND THE
CDFNT...BELIEVE ANOTHER ROUND OF LOW END MVFR CIGS WILL DEVELOP
WITH GUSTY NLY WINDS. WINDS WILL GRADUALLY DIMINISH LATE TONIGHT
WITH CLOUDS CLEARING.
SPECIFICS FOR KSTL...AREA OF SHRA CURRENTLY TO THE S OF TERMINAL
MAY IMPACT TERMINAL AROUND 14Z...BUT MAY REMAIN JUST E OF SITE.
EXPECT LOW MVFR CIGS...AND POSSIBLY IFR CIGS TO REACH TERMINAL
WITH OR JUST AFTER PRECIP. THESE CIGS SHUD GRADUALLY LIFT THIS
MORNING...BUT WILL LIKELY BE SLOW TO DO SO. EXPECT TSRA TO DEVELOP
AND IMPACT THE TERMINAL THIS AFTERNOON. HOWEVER...TIMING IS STILL
UNCERTAIN AS TSRA MAY DEVELOP AHEAD OF THE APPROACHING CDFNT.
EXPECT LOW MVFR CIGS AGAIN BEHIND THE FNT WITH GUSTY NLY WINDS.
WINDS SHUD GRADUALLY DIMINISH WITH CIGS BECOMING VFR LATE TONIGHT.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
946 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL SUPPLY OUR REGION WITH
ONE MORE BEAUTIFUL DAY AS TEMPERATURES WILL SOAR WELL ABOVE NORMAL.
CONDITIONS WILL THEN DETERIORATE TONIGHT AS A COMPLEX STORM SYSTEM
WILL APPROACH FROM THE OHIO VALLEY. THE MOISTURE RICH SYSTEM WILL
SPREAD A SOAKING RAIN ACROSS OUR REGION LATE TONIGHT AND TUESDAY...
WITH SOME SITES PICKING UP OVER AN INCH OF RAIN. HIGH PRESSURE WILL
BRING US A CRISP FALL LIKE DAY FOR WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
PATCHY FOG/STRATUS LINGERING OVER THE SOUTHERN TIER WILL DISSIPATE
BY 11Z. OTHERWISE...MORE IDEAL LATE SUMMER WEATHER IS ON TAP FOR
THE REST OF THE DAY AS HIGH PRESSURE ANCHORED OFF THE MIDDLE
ATLANTIC COAST REMAINS IN CONTROL. SUBSIDENCE...COUPLED WITH A
FAIRLY DRY AIRMASS...WILL RESULT IN MOSTLY SUNNY SKIES...ALTHOUGH
THERE WILL BE SOME INCREASE IN HIGH LEVEL CLOUDS LATER IN THE
AFTERNOON. THE SOUTHERLY FLOW BETWEEN THE SURFACE HIGH AND THE
MIDWEST COLD FRONT WILL ALLOW TEMPERATURES TO WARM WELL INTO THE
70S...AND POSSIBLY 80 DEGREES IN SOME OF THE WARMER VALLEYS.
THESE READINGS WILL BE AT LEAST 10 DEG ABOVE NORMAL.
CLOUDS WILL THEN INCREASE AND THICKEN ACROSS OUR AREA TONIGHT AS A
VERY ENERGETIC...COMPLEX STORM SYSTEM APPROACHES FROM THE OHIO VALLEY.
RICH GULF MOISTURE POOLING OVER THE SOUTHERN STATES AHEAD OF THE
DEVELOPING STORM SYSTEM WILL BE WHISKED NORTHWARDS WITHIN H85-70
WINDS OF 70-80 KTS. THE CORE OF THESE WINDS WILL BE SOUTH OF OUR
REGION TONIGHT...BUT ARE FORECAST TO MOVE OVER EASTERN NEW YORK ON
TUESDAY. THESE EXTREMELY ANOMALOUS WINDS WILL BE AS MUCH AS 5
STANDARD DEVIATIONS FROM NORMAL IN THEIR STRENGTH...WHICH EQUATE TO
AN EVENT THAT HAS LESS THAN ONE HALF OF A PERCENT CHANCE OF
OCCURRENCE FOR THE PARTICULAR CALENDAR DAY.
THE COMPLEX STORM SYSTEM ITSELF WILL FEATURE A WAVY FRONTAL BOUNDARY
THAT WILL EVENTUALLY INCLUDE A DEEPENING SFC LOW. THE BURGEONING LOW
WILL RIDE ALONG THE FRONT AND LIFT FROM ABOUT WEST VIRGINIA LATE
TONIGHT TO OUR FINGER LAKES ON TUESDAY. A POTENT SHORTWAVE DIVING
INTO THE BASE OF A DIGGING H5 TROUGH OVER THE UPPER MISSISSIPPI
VALLEY WILL ENERGIZE THIS SFC WAVE...WHILE A H25 JET OF 140 KTS OVER
THE UPPER GREAT LAKES WILL PLACE OUR FORECAST AREA UNDER THE
INFLUENCE OF THE JET ENTRANCE REGION. THE COMBINATION OF THE LIFT
FROM THE RR QUAD OF THE H25 JET...THE STRONG LOW LEVEL JET AND
STEADY HGT FALLS WILL PRODUCE DEEP ASCENT FOR THE MOISTURE RICH
AIRMASS. PWAT VALUES WILL INCREASE TO MORE THAN 1.5" FOR MOST SITES.
BREAKING THIS DOWN INTO A FORECAST FOR TONIGHT...RAIN SHOULD
APPROACH THE NEW YORK PENNSYLVANIA LINE AROUND MIDNIGHT...THEN
SPREAD NORTH-NORTHEAST DURING THE REMAINING OVERNIGHT HOURS. THE
RAIN SHOULD REACH THE THOUSANDS ISLAND REGION BY ABOUT DAYBREAK.
BECAUSE OF THE STRONG SOUTHERLY FLOW ALOFT...TEMPS SHOULD REMAIN
WELL ABOVE SEASONAL VALUES TONIGHT WITH LOWS ONLY FORECAST TO DROP
TO WITHIN A COUPLE DEGREES OF 60. NEAR LAKE ERIE AND OVER PARTS OF
THE IAG FRONTIER...LOWS MAY BE CLOSER TO 65. AGAIN...THESE VALUES
WILL BE 10 OR MORE DEG F ABOVE NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
VERY ACTIVE WEATHER WILL KICK OFF THIS PERIOD AS A SHARP UPPER LEVEL
TROUGH SLIDES EAST ACROSS THE GREAT LAKES REGION. AT THE SURFACE...
AN ASSOCIATED COMPLEX SURFACE LOW OVER OHIO AND SOUTHERN ONTARIO
TUESDAY MORNING WILL LIFT NORTHEAST INTO QUEBEC BY TUESDAY
EVENING...BEFORE RAPIDLY EJECTING NORTHWARD INTO LABRADOR BY
WEDNESDAY MORNING.
AS HAS BEEN PREVIOUSLY DETAILED IN THIS SPACE...THIS SYSTEM WILL BE
ACCOMPANIED BY A RICH SUPPLY OF GULF MOISTURE...WITH PRECIPITABLE
WATER VALUES RISING TO BETWEEN 1.5 AND 2 INCHES COURTESY OF THE DEEP
SOUTHWESTERLY SYNOPTIC-SCALE FLOW PRECEDING THE LOW. PLENTY OF
FORCING MECHANISMS WILL ALSO BE IN PLACE TO STRONGLY LIFT THIS
MOISTURE...INCLUDING STRONG HEIGHT FALLS AND WARM AIR ADVECTION
ALOFT...EXCELLENT LOW LEVEL CONVERGENCE IN THE VICINITY OF THE
SURFACE WAVE AND AT THE NOSE OF A DEVELOPING 70-80 KT LOW LEVEL
JET...AND STRONG UPPER LEVEL JET DYNAMICS SUPPLIED BY THE RIGHT REAR
QUAD OF A 120+ KT UPPER LEVEL JET STREAK. IT SHOULD GO WITHOUT
SAYING THAT ALL OF THIS MOISTURE AND LIFT WILL ADD UP TO A NEAR
CERTAINTY OF RAINFALL ON TUESDAY...SOME OF WHICH COULD BE HEAVY AT
TIMES. IN ADDITION...SOME WEAK ELEVATED INSTABILITY WILL ALSO BE
PRESENT ALOFT...AND THIS WILL ALSO ALLOW FOR THE POSSIBILITY OF SOME
ISOLATED EMBEDDED THUNDERSTORMS...ESPECIALLY GIVEN THE VERY STRONG
AND DYNAMIC NATURE OF THIS SYSTEM.
IN TERMS OF POTENTIAL RAINFALL AMOUNTS...THE NAM/GFS/GEM/ECMWF HAVE
ALL COME INTO BETTER AGREEMENT ON A SOMEWHAT MORE EASTERLY TRACK TO
THE SURFACE WAVE COMPARED TO 24 HOURS AGO...WITH THE MODEL CONSENSUS
THUS SUPERIMPOSING THE BEST OVERALL LIFT AND RICHEST MOISTURE...AND
CONSEQUENTLY THE GREATEST QPF...ACROSS OUR EASTERN FINGER LAKES AND
NORTH COUNTRY ZONES. IN THIS SPECIFIC REGION...A BLEND OF THE ABOVE
GUIDANCE PACKAGES SUGGEST THAT RAINFALL AMOUNTS OF 1 TO 1.5 INCHES
APPEAR POSSIBLE...WITH LOCALIZED AMOUNTS UP TO 2 INCHES NOT OUT OF
THE QUESTION. MEANWHILE FURTHER TO THE WEST...SOMEWHAT LESSER
RAINFALL AMOUNTS OF A HALF INCH TO AN INCH NOW APPEAR MORE LIKELY.
GIVEN THE VERY DRY ANTECEDENT CONDITIONS...THESE RAINFALL AMOUNTS
WILL BE UNLIKELY TO CAUSE ANY REAL FLOODING CONCERNS ACROSS LARGE
AREAS OR ALONG OUR LARGER CREEKS AND RIVERS...WITH ANY ISSUES MORE
THAN LIKELY REMAINING CONFINED TO LOCALIZED AREAS ALONG SMALLER
STREAMS AND LOW LYING/OTHER AREAS OF POOR DRAINAGE ACROSS OUR
EASTERN ZONES.
WITH ALL OF THE ABOVE IN MIND...HAVE ELECTED TO CONFINE ANY AREAS OF
POTENTIALLY HEAVY RAIN ON TUESDAY TO AREAS FROM THE GENESEE VALLEY
EASTWARD IN THE GRIDS AND WORDED FORECAST...AND WILL ALSO PULL BACK
SOMEWHAT ON THE HEAVY RAIN POTENTIAL IN THE HWO...AGAIN FOCUSING
THIS MORE ON OUR EASTERN ZONES WHERE THE HEAVIER RAINFALL IS MORE
LIKELY.
IN TERMS OF THE TIMING OF THE STEADIEST RAIN...THE ABOVE MODEL
CONSENSUS SUPPORTS A SOMEWHAT FASTER OVERALL TIMING COMPARED TO WHAT
WAS SEEN YESTERDAY...WITH THE STEADIEST AND MOST WIDESPREAD RAIN NOW
APPEARING AS IF IT WILL FALL BETWEEN MID TUESDAY MORNING AND MID
TUESDAY AFTERNOON. AFTER THAT TIME...THE STEADIEST RAINS WILL
QUICKLY TAPER OFF FROM WEST TO EAST BETWEEN LATE TUESDAY AFTERNOON
AND TUESDAY EVENING WITH THE PASSAGE OF THE TRAILING COLD FRONT...
WITH THE BACK EDGE OF THIS NOW APPEARING LIKELY TO EXIT OUR EASTERN
ZONES BETWEEN 03Z AND 06Z WEDNESDAY.
IN THE WAKE OF THE TRAILING COLD FRONT...A WEST-NORTHWESTERLY FLOW
OF MUCH COOLER AIR WILL FLOOD ACROSS THE REGION LATER TUESDAY AND
TUESDAY NIGHT...WITH 850 MB TEMPS PLUNGING TO BETWEEN 0C AND +3C BY
WEDNESDAY MORNING...THEN REMAINING AT THESE LEVELS RIGHT THROUGH
WEDNESDAY. WITH LAKE SURFACE TEMPS STILL RUNNING AROUND 21C...THIS
WILL BE PLENTY COLD ENOUGH TO SET OFF A LAKE RESPONSE...HOWEVER
MOISTURE WILL ONCE AGAIN BE A BIG LIMITING FACTOR THANKS TO
PLENTIFUL DRY AIR AND SUBSIDENCE ADVECTING IN BEHIND THE DEPARTING
LOW/COLD FRONT. WITH THE BULK OF ANY MOISTURE CONFINED TO 5-6 KFT OR
BELOW...WILL ONLY INDICATE SOME LINGERING LOWER-END CHANCE POPS
EAST-SOUTHEAST OF THE LAKES TUESDAY NIGHT...WITH ANY SCATTERED LAKE
EFFECT RAIN SHOWERS THEN FALLING APART ALTOGETHER ON WEDNESDAY WITH
DIURNAL INFLUENCES...AND AS HIGH PRESSURE BUILDS DIRECTLY OVERHEAD
ALONG WITH FURTHER DRYING AND INCREASING SUBSIDENCE. AFTER
THAT...DRY AND QUIET WEATHER IS EXPECTED TO CONTINUE THROUGH
WEDNESDAY NIGHT WITH THE AXIS OF THE AFOREMENTIONED SURFACE RIDGE
REMAINING PARKED DIRECTLY OVERHEAD.
WITH REGARD TO TEMPERATURES...FOLLOWING HIGHS IN THE MID 60S TO
LOWER 70S ON TUESDAY...EXPECT A SHARP COOLDOWN FOR THE REMAINDER
OF THE PERIOD GIVEN THE STRONG COLD AIR ADVECTION PATTERN BEHIND
THE DEPARTING LOW. EXPECT LOWS TO FALL BACK TO THE MID TO UPPER
40S TUESDAY NIGHT...WITH DAYTIME HIGHS ON WEDNESDAY THEN BARELY
REACHING 60 OR SO ACROSS THE LOWER ELEVATIONS...AND LIKELY NOT
MAKING IT OUT OF THE UPPER 50S ACROSS THE HIGHER TERRAIN. EVEN
COOLER READINGS IN THE LOWER TO MID 40S WILL THEN FOLLOW FOR
WEDNESDAY NIGHT...WITH UPPER 30S FOUND ACROSS INTERIOR PORTIONS OF
THE SOUTHERN TIER AND NORTH COUNTRY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE FIRST HALF OF THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A
LINGERING BROAD/FLAT TROUGH OVER EASTERN NORTH AMERICA RELOADING TO
OUR WEST...AS ANOTHER STRONG SHORTWAVE TROUGH PLUNGES SOUTHEASTWARD
ACROSS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. OUT AHEAD OF
THIS SHORTWAVE...THE PREVAILING SYNOPTIC-SCALE FLOW WILL AGAIN TURN
SOUTHWESTERLY...AND THIS WILL HELP TO TRANSPORT MUCH WARMER AIR BACK
INTO OUR REGION FOR A COUPLE OF DAYS. A BLEND OF THE 00Z GFS AND
ECMWF SUGGESTS 850 MB TEMPS RECOVERING TO BETWEEN +5C AND +8C
THURSDAY AND TO AROUND +11C/+12C FRIDAY...WHICH SHOULD BE ENOUGH TO
BOOST HIGH TEMPS BACK INTO THE 65-70 DEGREE RANGE ON THURSDAY...AND
AT LEAST THE LOWER TO MID 70S ON FRIDAY. THUS...WEDNESDAY`S SHARP
COOLDOWN WILL BE VERY BRIEF...WITH TEMPERATURES RECOVERING TO A BIT
ABOVE NORMAL LEVELS BY THE END OF THE WORK WEEK.
IN TERMS OF PRECIPITATION CHANCES...THE GFS AND ECMWF ARE NOW IN
BETTER AGREEMENT THAT THE VAST MAJORITY OF THE THURSDAY-FRIDAY TIME
FRAME SHOULD REMAIN DRY. BOTH MODELS WEAKEN AN INITIAL LEAD COLD
FRONT AS IT TRIES TO PRESS TOWARD OUR AREA ON THURSDAY...WITH THIS
FEATURE EVENTUALLY FALLING APART OVER SOUTHERN ONTARIO LATE THURSDAY
AND THURSDAY NIGHT. BOTH PACKAGES ALSO ARE NOW IN BETTER AGREEMENT
ON THE EVOLUTION OF A SUBSEQUENT SURFACE WAVE AND ASSOCIATED
STRONGER COLD FRONT...WITH THIS LATTER FEATURE ONLY APPROACHING
FAR WESTERN NEW YORK BY LATE FRIDAY AFTERNOON/FRIDAY EVENING. WITH
THE ABOVE IN MIND...HAVE KEPT PRECIP CHANCES FOR BOTH DAYS LARGELY
CONFINED TO SLIGHT CHANCE OR LESS...WITH ONLY SOME LOW CHANCE POPS
INDICATED ACROSS FAR WESTERN NEW YORK LATER FRIDAY AFTERNOON.
AFTER THAT...BOTH GUIDANCE PACKAGES DIG THE LARGE-SCALE UPPER TROUGH
DEEPER INTO THE CENTRAL AND EASTERN GREAT LAKES NEXT WEEKEND...WITH
THE AFOREMENTIONED SECOND COLD FRONT SLOWLY PUSHING ACROSS THE AREA
BETWEEN FRIDAY NIGHT AND SATURDAY...FOLLOWED BY A SECONDARY AND
WEAKER AREA OF LOW PRESSURE PASSING BY TO OUR NORTH ON SUNDAY. AT
THIS DISTANT JUNCTURE...THIS EVOLUTION IN THE PATTERN WILL SUPPORT
SOME BROADBRUSH LOWER-END SHOWER CHANCES BOTH DAYS...ALONG WITH A
TREND TOWARD PROGRESSIVELY COOLER TEMPERATURES AS THE COLD POOL
ASSOCIATED WITH THE UPPER LOW OVERSPREADS OUR REGION.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE CENTERED ALONG THE MID ATLANTIC COAST WILL KEEP FAIR
VFR WEATHER IN PLACE OVER OUR REGION THROUGH THE FIRST HALF OF
TONIGHT...ALTHOUGH THERE COULD BE ANOTHER HOUR OR TWO OF MVFR VSBYS
IN EARLY MORNING FOG FOR SITES SUCH AS KJHW AND KELZ.
DURING THE COURSE OF TONIGHT THOUGH...A COMPLEX STORM SYSTEM WILL
TAKE SHAPE OVER THE UPPER OHIO VALLEY AND SPREAD RAIN AND GENERALLY
DETERIORATING CONDITIONS NORTHWARDS. IFR CONDITIONS WILL DEVELOP
OVER THE WESTERN SOUTHERN TIER WITH MVFR VSBYS/CIGS POSSIBLE FOR THE
REMAINDER OF THE WRN COUNTIES.
SOME LOW LEVEL WIND SHEAR HAS BEEN ADDED TO THE KROC AND KART TAFS
FOR MARGINAL LLWS CONDITIONS LATE TONIGHT.
OUTLOOK...
TUESDAY AND TUESDAY NIGHT...MVFR/IFR WITH RAIN. LLWS.
WEDNESDAY...IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
&&
.MARINE...
WHILE HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST SHOULD
KEEP CONDITIONS BELOW SMALL CRAFT ADVISORY CRITERIA TODAY...WATERS
WILL BE QUITE CHOPPY ACROSS THE EASTERN PART OF LAKE ONTARIO THIS
MORNING AND THEN OVER PARTS OF LAKE ERIE DURING THE MIDDAY AND EARLY
AFTERNOON. IN THOSE AREAS...MODERATE SOUTHERLIES WILL PRODUCE WAVES
OF 2 TO 4 FEET SO THEY WILL HAVE TO BE CLOSELY WATCHED.
WINDS AND WAVES WILL BRIEFLY SUBSIDE ON BOTH LAKES THIS EVENING...
THEN A COMPLEX STORM SYSTEM WILL APPROACH THE LOWER GREAT LAKES
DURING THE OVERNIGHT. WINDS AHEAD OF THIS STORM SYSTEM WILL FRESHEN
OVER EASTERN LAKE ONTARIO LATER TONIGHT...POSSIBLY PRODUCING SCA
CONDITIONS BY DAYBREAK TUESDAY.
STRONGER WINDS ARE EXPECTED IN THE WAKE OF THE STORM SYSTEM TUESDAY
AFTERNOON AND NIGHT WITH FRESH WEST TO NORTHWEST BREEZES PRODUCING
SCA CONDITIONS ACROSS MUCH OF LAKE ONTARIO AND POSSIBLY FOR A SHORT
TIME...ON LAKE ERIE.
HIGH PRESSURE WILL MOVE IN ON WEDNESDAY TO PROMOTE WEAKER WINDS AND
LOWER WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RSH
NEAR TERM...RSH/TJP
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...RSH
MARINE...RSH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
735 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL SUPPLY OUR REGION WITH
ONE MORE BEAUTIFUL DAY AS TEMPERATURES WILL SOAR WELL ABOVE NORMAL.
CONDITIONS WILL THEN DETERIORATE TONIGHT AS A COMPLEX STORM SYSTEM
WILL APPROACH FROM THE OHIO VALLEY. THE MOISTURE RICH SYSTEM WILL
SPREAD A SOAKING RAIN ACROSS OUR REGION LATE TONIGHT AND TUESDAY...
WITH SOME SITES PICKING UP OVER AN INCH OF RAIN. HIGH PRESSURE WILL
BRING US A CRISP FALL LIKE DAY FOR WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
IF YOU LIKED THE WEATHER ON SUNDAY...THEN YOU ARE GOING TO LOVE IT
TODAY. HIGH PRESSURE OFF THE MIDDLE ATLANTIC COAST WILL KEEP PLENTY
OF SUBSIDENCE OVER OUR REGION...AND COUPLED WITH A FAIRLY DRY
AIRMASS...WE CAN ANTICIPATE ANOTHER SUN FILLED DAY. THERE WILL BE AN
INCREASE IN HIGH LEVEL CLOUDS LATER IN THE AFTERNOON...BUT NOT
BEFORE H85 TEMPS OF 10C HELP TO BOOST OUR NEAR SFC TEMPS WELL INTO
THE 70S. IN FACT...SOME OF THE WARMER VALLEYS MAY TICKLE 80. THESE
READINGS WILL BE AT LEAST 10 DEG ABOVE NORMAL.
CLOUDS WILL THEN INCREASE AND THICKEN ACROSS OUR FORECAST AREA
DURING THE COURSE OF TONIGHT AS A VERY ENERGETIC...COMPLEX STORM
SYSTEM WILL APPROACH FROM THE OHIO VALLEY. RICH GULF MOISTURE
POOLING OVER THE SOUTHERN STATES AHEAD OF THE DEVELOPING STORM
SYSTEM WILL BE WHISKED NORTHWARDS WITHIN H85-70 WINDS OF 70-80 KTS.
THE CORE OF THESE WINDS WILL BE SOUTH OF OUR REGION TONIGHT...BUT
ARE FORECAST TO MOVE OVER EASTERN NEW YORK ON TUESDAY. THESE
EXTREMELY ANOMALOUS WINDS WILL BE AS MUCH AS 5 STANDARD DEVIATIONS
FROM NORMAL IN THEIR STRENGTH...WHICH EQUATE TO AN EVENT THAT HAS
LESS THAN ONE HALF OF A PERCENT CHANCE OF OCCURRENCE FOR THE
PARTICULAR CALENDAR DAY.
THE COMPLEX STORM SYSTEM ITSELF WILL FEATURE A WAVY FRONTAL BOUNDARY
THAT WILL EVENTUALLY INCLUDE A DEEPENING SFC LOW. THE BURGEONING LOW
WILL RIDE ALONG THE FRONT AND LIFT FROM ABOUT WEST VIRGINIA LATE
TONIGHT TO OUR FINGER LAKES ON TUESDAY. A POTENT SHORTWAVE DIVING
INTO THE BASE OF A DIGGING H5 TROUGH OVER THE UPPER MISSISSIPPI
VALLEY WILL ENERGIZE THIS SFC WAVE...WHILE A H25 JET OF 140 KTS OVER
THE UPPER GREAT LAKES WILL PLACE OUR FORECAST AREA UNDER THE
INFLUENCE OF THE JET ENTRANCE REGION. THE COMBINATION OF THE LIFT
FROM THE RR QUAD OF THE H25 JET...THE STRONG LOW LEVEL JET AND
STEADY HGT FALLS WILL PRODUCE DEEP ASCENT FOR THE MOISTURE RICH
AIRMASS. PWAT VALUES WILL INCREASE TO MORE THAN 1.5" FOR MOST SITES.
BREAKING THIS DOWN INTO A FORECAST FOR TONIGHT...RAIN SHOULD
APPROACH THE NEW YORK PENNSYLVANIA LINE AROUND MIDNIGHT...THEN
SPREAD NORTH-NORTHEAST DURING THE REMAINING OVERNIGHT HOURS. THE
RAIN SHOULD REACH THE THOUSANDS ISLAND REGION BY ABOUT DAYBREAK.
BECAUSE OF THE STRONG SOUTHERLY FLOW ALOFT...TEMPS SHOULD REMAIN
WELL ABOVE SEASONAL VALUES TONIGHT WITH LOWS ONLY FORECAST TO DROP
TO WITHIN A COUPLE DEGREES OF 60. NEAR LAKE ERIE AND OVER PARTS OF
THE IAG FRONTIER...LOWS MAY BE CLOSER TO 65. AGAIN...THESE VALUES
WILL BE 10 OR MORE DEG F ABOVE NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
VERY ACTIVE WEATHER WILL KICK OFF THIS PERIOD AS A SHARP UPPER LEVEL
TROUGH SLIDES EAST ACROSS THE GREAT LAKES REGION. AT THE SURFACE...
AN ASSOCIATED COMPLEX SURFACE LOW OVER OHIO AND SOUTHERN ONTARIO
TUESDAY MORNING WILL LIFT NORTHEAST INTO QUEBEC BY TUESDAY
EVENING...BEFORE RAPIDLY EJECTING NORTHWARD INTO LABRADOR BY
WEDNESDAY MORNING.
AS HAS BEEN PREVIOUSLY DETAILED IN THIS SPACE...THIS SYSTEM WILL BE
ACCOMPANIED BY A RICH SUPPLY OF GULF MOISTURE...WITH PRECIPITABLE
WATER VALUES RISING TO BETWEEN 1.5 AND 2 INCHES COURTESY OF THE DEEP
SOUTHWESTERLY SYNOPTIC-SCALE FLOW PRECEDING THE LOW. PLENTY OF
FORCING MECHANISMS WILL ALSO BE IN PLACE TO STRONGLY LIFT THIS
MOISTURE...INCLUDING STRONG HEIGHT FALLS AND WARM AIR ADVECTION
ALOFT...EXCELLENT LOW LEVEL CONVERGENCE IN THE VICINITY OF THE
SURFACE WAVE AND AT THE NOSE OF A DEVELOPING 70-80 KT LOW LEVEL
JET...AND STRONG UPPER LEVEL JET DYNAMICS SUPPLIED BY THE RIGHT REAR
QUAD OF A 120+ KT UPPER LEVEL JET STREAK. IT SHOULD GO WITHOUT
SAYING THAT ALL OF THIS MOISTURE AND LIFT WILL ADD UP TO A NEAR
CERTAINTY OF RAINFALL ON TUESDAY...SOME OF WHICH COULD BE HEAVY AT
TIMES. IN ADDITION...SOME WEAK ELEVATED INSTABILITY WILL ALSO BE
PRESENT ALOFT...AND THIS WILL ALSO ALLOW FOR THE POSSIBILITY OF SOME
ISOLATED EMBEDDED THUNDERSTORMS...ESPECIALLY GIVEN THE VERY STRONG
AND DYNAMIC NATURE OF THIS SYSTEM.
IN TERMS OF POTENTIAL RAINFALL AMOUNTS...THE NAM/GFS/GEM/ECMWF HAVE
ALL COME INTO BETTER AGREEMENT ON A SOMEWHAT MORE EASTERLY TRACK TO
THE SURFACE WAVE COMPARED TO 24 HOURS AGO...WITH THE MODEL CONSENSUS
THUS SUPERIMPOSING THE BEST OVERALL LIFT AND RICHEST MOISTURE...AND
CONSEQUENTLY THE GREATEST QPF...ACROSS OUR EASTERN FINGER LAKES AND
NORTH COUNTRY ZONES. IN THIS SPECIFIC REGION...A BLEND OF THE ABOVE
GUIDANCE PACKAGES SUGGEST THAT RAINFALL AMOUNTS OF 1 TO 1.5 INCHES
APPEAR POSSIBLE...WITH LOCALIZED AMOUNTS UP TO 2 INCHES NOT OUT OF
THE QUESTION. MEANWHILE FURTHER TO THE WEST...SOMEWHAT LESSER
RAINFALL AMOUNTS OF A HALF INCH TO AN INCH NOW APPEAR MORE LIKELY.
GIVEN THE VERY DRY ANTECEDENT CONDITIONS...THESE RAINFALL AMOUNTS
WILL BE UNLIKELY TO CAUSE ANY REAL FLOODING CONCERNS ACROSS LARGE
AREAS OR ALONG OUR LARGER CREEKS AND RIVERS...WITH ANY ISSUES MORE
THAN LIKELY REMAINING CONFINED TO LOCALIZED AREAS ALONG SMALLER
STREAMS AND LOW LYING/OTHER AREAS OF POOR DRAINAGE ACROSS OUR
EASTERN ZONES.
WITH ALL OF THE ABOVE IN MIND...HAVE ELECTED TO CONFINE ANY AREAS OF
POTENTIALLY HEAVY RAIN ON TUESDAY TO AREAS FROM THE GENESEE VALLEY
EASTWARD IN THE GRIDS AND WORDED FORECAST...AND WILL ALSO PULL BACK
SOMEWHAT ON THE HEAVY RAIN POTENTIAL IN THE HWO...AGAIN FOCUSING
THIS MORE ON OUR EASTERN ZONES WHERE THE HEAVIER RAINFALL IS MORE
LIKELY.
IN TERMS OF THE TIMING OF THE STEADIEST RAIN...THE ABOVE MODEL
CONSENSUS SUPPORTS A SOMEWHAT FASTER OVERALL TIMING COMPARED TO WHAT
WAS SEEN YESTERDAY...WITH THE STEADIEST AND MOST WIDESPREAD RAIN NOW
APPEARING AS IF IT WILL FALL BETWEEN MID TUESDAY MORNING AND MID
TUESDAY AFTERNOON. AFTER THAT TIME...THE STEADIEST RAINS WILL
QUICKLY TAPER OFF FROM WEST TO EAST BETWEEN LATE TUESDAY AFTERNOON
AND TUESDAY EVENING WITH THE PASSAGE OF THE TRAILING COLD FRONT...
WITH THE BACK EDGE OF THIS NOW APPEARING LIKELY TO EXIT OUR EASTERN
ZONES BETWEEN 03Z AND 06Z WEDNESDAY.
IN THE WAKE OF THE TRAILING COLD FRONT...A WEST-NORTHWESTERLY FLOW
OF MUCH COOLER AIR WILL FLOOD ACROSS THE REGION LATER TUESDAY AND
TUESDAY NIGHT...WITH 850 MB TEMPS PLUNGING TO BETWEEN 0C AND +3C BY
WEDNESDAY MORNING...THEN REMAINING AT THESE LEVELS RIGHT THROUGH
WEDNESDAY. WITH LAKE SURFACE TEMPS STILL RUNNING AROUND 21C...THIS
WILL BE PLENTY COLD ENOUGH TO SET OFF A LAKE RESPONSE...HOWEVER
MOISTURE WILL ONCE AGAIN BE A BIG LIMITING FACTOR THANKS TO
PLENTIFUL DRY AIR AND SUBSIDENCE ADVECTING IN BEHIND THE DEPARTING
LOW/COLD FRONT. WITH THE BULK OF ANY MOISTURE CONFINED TO 5-6 KFT OR
BELOW...WILL ONLY INDICATE SOME LINGERING LOWER-END CHANCE POPS
EAST-SOUTHEAST OF THE LAKES TUESDAY NIGHT...WITH ANY SCATTERED LAKE
EFFECT RAIN SHOWERS THEN FALLING APART ALTOGETHER ON WEDNESDAY WITH
DIURNAL INFLUENCES...AND AS HIGH PRESSURE BUILDS DIRECTLY OVERHEAD
ALONG WITH FURTHER DRYING AND INCREASING SUBSIDENCE. AFTER
THAT...DRY AND QUIET WEATHER IS EXPECTED TO CONTINUE THROUGH
WEDNESDAY NIGHT WITH THE AXIS OF THE AFOREMENTIONED SURFACE RIDGE
REMAINING PARKED DIRECTLY OVERHEAD.
WITH REGARD TO TEMPERATURES...FOLLOWING HIGHS IN THE MID 60S TO
LOWER 70S ON TUESDAY...EXPECT A SHARP COOLDOWN FOR THE REMAINDER
OF THE PERIOD GIVEN THE STRONG COLD AIR ADVECTION PATTERN BEHIND
THE DEPARTING LOW. EXPECT LOWS TO FALL BACK TO THE MID TO UPPER
40S TUESDAY NIGHT...WITH DAYTIME HIGHS ON WEDNESDAY THEN BARELY
REACHING 60 OR SO ACROSS THE LOWER ELEVATIONS...AND LIKELY NOT
MAKING IT OUT OF THE UPPER 50S ACROSS THE HIGHER TERRAIN. EVEN
COOLER READINGS IN THE LOWER TO MID 40S WILL THEN FOLLOW FOR
WEDNESDAY NIGHT...WITH UPPER 30S FOUND ACROSS INTERIOR PORTIONS OF
THE SOUTHERN TIER AND NORTH COUNTRY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE FIRST HALF OF THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A
LINGERING BROAD/FLAT TROUGH OVER EASTERN NORTH AMERICA RELOADING TO
OUR WEST...AS ANOTHER STRONG SHORTWAVE TROUGH PLUNGES SOUTHEASTWARD
ACROSS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. OUT AHEAD OF
THIS SHORTWAVE...THE PREVAILING SYNOPTIC-SCALE FLOW WILL AGAIN TURN
SOUTHWESTERLY...AND THIS WILL HELP TO TRANSPORT MUCH WARMER AIR BACK
INTO OUR REGION FOR A COUPLE OF DAYS. A BLEND OF THE 00Z GFS AND
ECMWF SUGGESTS 850 MB TEMPS RECOVERING TO BETWEEN +5C AND +8C
THURSDAY AND TO AROUND +11C/+12C FRIDAY...WHICH SHOULD BE ENOUGH TO
BOOST HIGH TEMPS BACK INTO THE 65-70 DEGREE RANGE ON THURSDAY...AND
AT LEAST THE LOWER TO MID 70S ON FRIDAY. THUS...WEDNESDAY`S SHARP
COOLDOWN WILL BE VERY BRIEF...WITH TEMPERATURES RECOVERING TO A BIT
ABOVE NORMAL LEVELS BY THE END OF THE WORK WEEK.
IN TERMS OF PRECIPITATION CHANCES...THE GFS AND ECMWF ARE NOW IN
BETTER AGREEMENT THAT THE VAST MAJORITY OF THE THURSDAY-FRIDAY TIME
FRAME SHOULD REMAIN DRY. BOTH MODELS WEAKEN AN INITIAL LEAD COLD
FRONT AS IT TRIES TO PRESS TOWARD OUR AREA ON THURSDAY...WITH THIS
FEATURE EVENTUALLY FALLING APART OVER SOUTHERN ONTARIO LATE THURSDAY
AND THURSDAY NIGHT. BOTH PACKAGES ALSO ARE NOW IN BETTER AGREEMENT
ON THE EVOLUTION OF A SUBSEQUENT SURFACE WAVE AND ASSOCIATED
STRONGER COLD FRONT...WITH THIS LATTER FEATURE ONLY APPROACHING
FAR WESTERN NEW YORK BY LATE FRIDAY AFTERNOON/FRIDAY EVENING. WITH
THE ABOVE IN MIND...HAVE KEPT PRECIP CHANCES FOR BOTH DAYS LARGELY
CONFINED TO SLIGHT CHANCE OR LESS...WITH ONLY SOME LOW CHANCE POPS
INDICATED ACROSS FAR WESTERN NEW YORK LATER FRIDAY AFTERNOON.
AFTER THAT...BOTH GUIDANCE PACKAGES DIG THE LARGE-SCALE UPPER TROUGH
DEEPER INTO THE CENTRAL AND EASTERN GREAT LAKES NEXT WEEKEND...WITH
THE AFOREMENTIONED SECOND COLD FRONT SLOWLY PUSHING ACROSS THE AREA
BETWEEN FRIDAY NIGHT AND SATURDAY...FOLLOWED BY A SECONDARY AND
WEAKER AREA OF LOW PRESSURE PASSING BY TO OUR NORTH ON SUNDAY. AT
THIS DISTANT JUNCTURE...THIS EVOLUTION IN THE PATTERN WILL SUPPORT
SOME BROADBRUSH LOWER-END SHOWER CHANCES BOTH DAYS...ALONG WITH A
TREND TOWARD PROGRESSIVELY COOLER TEMPERATURES AS THE COLD POOL
ASSOCIATED WITH THE UPPER LOW OVERSPREADS OUR REGION.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE CENTERED ALONG THE MID ATLANTIC COAST WILL KEEP FAIR
VFR WEATHER IN PLACE OVER OUR REGION THROUGH THE FIRST HALF OF
TONIGHT...ALTHOUGH THERE COULD BE ANOTHER HOUR OR TWO OF MVFR VSBYS
IN EARLY MORNING FOG FOR SITES SUCH AS KJHW AND KELZ.
DURING THE COURSE OF TONIGHT THOUGH...A COMPLEX STORM SYSTEM WILL
TAKE SHAPE OVER THE UPPER OHIO VALLEY AND SPREAD RAIN AND GENERALLY
DETERIORATING CONDITIONS NORTHWARDS. IFR CONDITIONS WILL DEVELOP
OVER THE WESTERN SOUTHERN TIER WITH MVFR VSBYS/CIGS POSSIBLE FOR THE
REMAINDER OF THE WRN COUNTIES.
SOME LOW LEVEL WIND SHEAR HAS BEEN ADDED TO THE KROC AND KART TAFS
FOR MARGINAL LLWS CONDITIONS LATE TONIGHT.
OUTLOOK...
TUESDAY AND TUESDAY NIGHT...MVFR/IFR WITH RAIN. LLWS.
WEDNESDAY...IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
&&
.MARINE...
WHILE HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST SHOULD
KEEP CONDITIONS BELOW SMALL CRAFT ADVISORY CRITERIA TODAY...WATERS
WILL BE QUITE CHOPPY ACROSS THE EASTERN PART OF LAKE ONTARIO THIS
MORNING AND THEN OVER PARTS OF LAKE ERIE DURING THE MIDDAY AND EARLY
AFTERNOON. IN THOSE AREAS...MODERATE SOUTHERLIES WILL PRODUCE WAVES
OF 2 TO 4 FEET SO THEY WILL HAVE TO BE CLOSELY WATCHED.
WINDS AND WAVES WILL BRIEFLY SUBSIDE ON BOTH LAKES THIS EVENING...
THEN A COMPLEX STORM SYSTEM WILL APPROACH THE LOWER GREAT LAKES
DURING THE OVERNIGHT. WINDS AHEAD OF THIS STORM SYSTEM WILL FRESHEN
OVER EASTERN LAKE ONTARIO LATER TONIGHT...POSSIBLY PRODUCING SCA
CONDITIONS BY DAYBREAK TUESDAY.
STRONGER WINDS ARE EXPECTED IN THE WAKE OF THE STORM SYSTEM TUESDAY
AFTERNOON AND NIGHT WITH FRESH WEST TO NORTHWEST BREEZES PRODUCING
SCA CONDITIONS ACROSS MUCH OF LAKE ONTARIO AND POSSIBLY FOR A SHORT
TIME...ON LAKE ERIE.
HIGH PRESSURE WILL MOVE IN ON WEDNESDAY TO PROMOTE WEAKER WINDS AND
LOWER WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...RSH
MARINE...RSH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
707 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL SUPPLY OUR REGION WITH
ONE MORE BEAUTIFUL DAY AS TEMPERATURES WILL SOAR WELL ABOVE NORMAL.
CONDITIONS WILL THEN DETERIORATE TONIGHT AS A COMPLEX STORM SYSTEM
WILL APPROACH FROM THE OHIO VALLEY. THE MOISTURE RICH SYSTEM WILL
SPREAD A SOAKING RAIN ACROSS OUR REGION LATE TONIGHT AND TUESDAY...
WITH SOME SITES PICKING UP OVER AN INCH OF RAIN. HIGH PRESSURE WILL
BRING US A CRISP FALL LIKE DAY FOR WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
IF YOU LIKED THE WEATHER ON SUNDAY...THEN YOU ARE GOING TO LOVE IT
TODAY. HIGH PRESSURE OFF THE MIDDLE ATLANTIC COAST WILL KEEP PLENTY
OF SUBSIDENCE OVER OUR REGION...AND COUPLED WITH A FAIRLY DRY
AIRMASS...WE CAN ANTICIPATE ANOTHER SUN FILLED DAY. THERE WILL BE AN
INCREASE IN HIGH LEVEL CLOUDS LATER IN THE AFTERNOON...BUT NOT
BEFORE H85 TEMPS OF 10C HELP TO BOOST OUR NEAR SFC TEMPS WELL INTO
THE 70S. IN FACT...SOME OF THE WARMER VALLEYS MAY TICKLE 80. THESE
READINGS WILL BE AT LEAST 10 DEG ABOVE NORMAL.
CLOUDS WILL THEN INCREASE AND THICKEN ACROSS OUR FORECAST AREA
DURING THE COURSE OF TONIGHT AS A VERY ENERGETIC...COMPLEX STORM
SYSTEM WILL APPROACH FROM THE OHIO VALLEY. RICH GULF MOISTURE
POOLING OVER THE SOUTHERN STATES AHEAD OF THE DEVELOPING STORM
SYSTEM WILL BE WHISKED NORTHWARDS WITHIN H85-70 WINDS OF 70-80 KTS.
THE CORE OF THESE WINDS WILL BE SOUTH OF OUR REGION TONIGHT...BUT
ARE FORECAST TO MOVE OVER EASTERN NEW YORK ON TUESDAY. THESE
EXTREMELY ANOMALOUS WINDS WILL BE AS MUCH AS 5 STANDARD DEVIATIONS
FROM NORMAL IN THEIR STRENGTH...WHICH EQUATE TO AN EVENT THAT HAS
LESS THAN ONE HALF OF A PERCENT CHANCE OF OCCURRENCE FOR THE
PARTICULAR CALENDAR DAY.
THE COMPLEX STORM SYSTEM ITSELF WILL FEATURE A WAVY FRONTAL BOUNDARY
THAT WILL EVENTUALLY INCLUDE A DEEPENING SFC LOW. THE BURGEONING LOW
WILL RIDE ALONG THE FRONT AND LIFT FROM ABOUT WEST VIRGINIA LATE
TONIGHT TO OUR FINGER LAKES ON TUESDAY. A POTENT SHORTWAVE DIVING
INTO THE BASE OF A DIGGING H5 TROUGH OVER THE UPPER MISSISSIPPI
VALLEY WILL ENERGIZE THIS SFC WAVE...WHILE A H25 JET OF 140 KTS OVER
THE UPPER GREAT LAKES WILL PLACE OUR FORECAST AREA UNDER THE
INFLUENCE OF THE JET ENTRANCE REGION. THE COMBINATION OF THE LIFT
FROM THE RR QUAD OF THE H25 JET...THE STRONG LOW LEVEL JET AND
STEADY HGT FALLS WILL PRODUCE DEEP ASCENT FOR THE MOISTURE RICH
AIRMASS. PWAT VALUES WILL INCREASE TO MORE THAN 1.5" FOR MOST SITES.
BREAKING THIS DOWN INTO A FORECAST FOR TONIGHT...RAIN SHOULD
APPROACH THE NEW YORK PENNSYLVANIA LINE AROUND MIDNIGHT...THEN
SPREAD NORTH-NORTHEAST DURING THE REMAINING OVERNIGHT HOURS. THE
RAIN SHOULD REACH THE THOUSANDS ISLAND REGION BY ABOUT DAYBREAK.
BECAUSE OF THE STRONG SOUTHERLY FLOW ALOFT...TEMPS SHOULD REMAIN
WELL ABOVE SEASONAL VALUES TONIGHT WITH LOWS ONLY FORECAST TO DROP
TO WITHIN A COUPLE DEGREES OF 60. NEAR LAKE ERIE AND OVER PARTS OF
THE IAG FRONTIER...LOWS MAY BE CLOSER TO 65. AGAIN...THESE VALUES
WILL BE 10 OR MORE DEG F ABOVE NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
VERY ACTIVE WEATHER WILL KICK OFF THIS PERIOD AS A SHARP UPPER LEVEL
TROUGH SLIDES EAST ACROSS THE GREAT LAKES REGION. AT THE SURFACE...
AN ASSOCIATED COMPLEX SURFACE LOW OVER OHIO AND SOUTHERN ONTARIO
TUESDAY MORNING WILL LIFT NORTHEAST INTO QUEBEC BY TUESDAY
EVENING...BEFORE RAPIDLY EJECTING NORTHWARD INTO LABRADOR BY
WEDNESDAY MORNING.
AS HAS BEEN PREVIOUSLY DETAILED IN THIS SPACE...THIS SYSTEM WILL BE
ACCOMPANIED BY A RICH SUPPLY OF GULF MOISTURE...WITH PRECIPITABLE
WATER VALUES RISING TO BETWEEN 1.5 AND 2 INCHES COURTESY OF THE DEEP
SOUTHWESTERLY SYNOPTIC-SCALE FLOW PRECEDING THE LOW. PLENTY OF
FORCING MECHANISMS WILL ALSO BE IN PLACE TO STRONGLY LIFT THIS
MOISTURE...INCLUDING STRONG HEIGHT FALLS AND WARM AIR ADVECTION
ALOFT...EXCELLENT LOW LEVEL CONVERGENCE IN THE VICINITY OF THE
SURFACE WAVE AND AT THE NOSE OF A DEVELOPING 70-80 KT LOW LEVEL
JET...AND STRONG UPPER LEVEL JET DYNAMICS SUPPLIED BY THE RIGHT REAR
QUAD OF A 120+ KT UPPER LEVEL JET STREAK. IT SHOULD GO WITHOUT
SAYING THAT ALL OF THIS MOISTURE AND LIFT WILL ADD UP TO A NEAR
CERTAINTY OF RAINFALL ON TUESDAY...SOME OF WHICH COULD BE HEAVY AT
TIMES. IN ADDITION...SOME WEAK ELEVATED INSTABILITY WILL ALSO BE
PRESENT ALOFT...AND THIS WILL ALSO ALLOW FOR THE POSSIBILITY OF SOME
ISOLATED EMBEDDED THUNDERSTORMS...ESPECIALLY GIVEN THE VERY STRONG
AND DYNAMIC NATURE OF THIS SYSTEM.
IN TERMS OF POTENTIAL RAINFALL AMOUNTS...THE NAM/GFS/GEM/ECMWF HAVE
ALL COME INTO BETTER AGREEMENT ON A SOMEWHAT MORE EASTERLY TRACK TO
THE SURFACE WAVE COMPARED TO 24 HOURS AGO...WITH THE MODEL CONSENSUS
THUS SUPERIMPOSING THE BEST OVERALL LIFT AND RICHEST MOISTURE...AND
CONSEQUENTLY THE GREATEST QPF...ACROSS OUR EASTERN FINGER LAKES AND
NORTH COUNTRY ZONES. IN THIS SPECIFIC REGION...A BLEND OF THE ABOVE
GUIDANCE PACKAGES SUGGEST THAT RAINFALL AMOUNTS OF 1 TO 1.5 INCHES
APPEAR POSSIBLE...WITH LOCALIZED AMOUNTS UP TO 2 INCHES NOT OUT OF
THE QUESTION. MEANWHILE FURTHER TO THE WEST...SOMEWHAT LESSER
RAINFALL AMOUNTS OF A HALF INCH TO AN INCH NOW APPEAR MORE LIKELY.
GIVEN THE VERY DRY ANTECEDENT CONDITIONS...THESE RAINFALL AMOUNTS
WILL BE UNLIKELY TO CAUSE ANY REAL FLOODING CONCERNS ACROSS LARGE
AREAS OR ALONG OUR LARGER CREEKS AND RIVERS...WITH ANY ISSUES MORE
THAN LIKELY REMAINING CONFINED TO LOCALIZED AREAS ALONG SMALLER
STREAMS AND LOW LYING/OTHER AREAS OF POOR DRAINAGE ACROSS OUR
EASTERN ZONES.
WITH ALL OF THE ABOVE IN MIND...HAVE ELECTED TO CONFINE ANY AREAS OF
POTENTIALLY HEAVY RAIN ON TUESDAY TO AREAS FROM THE GENESEE VALLEY
EASTWARD IN THE GRIDS AND WORDED FORECAST...AND WILL ALSO PULL BACK
SOMEWHAT ON THE HEAVY RAIN POTENTIAL IN THE HWO...AGAIN FOCUSING
THIS MORE ON OUR EASTERN ZONES WHERE THE HEAVIER RAINFALL IS MORE
LIKELY.
IN TERMS OF THE TIMING OF THE STEADIEST RAIN...THE ABOVE MODEL
CONSENSUS SUPPORTS A SOMEWHAT FASTER OVERALL TIMING COMPARED TO WHAT
WAS SEEN YESTERDAY...WITH THE STEADIEST AND MOST WIDESPREAD RAIN NOW
APPEARING AS IF IT WILL FALL BETWEEN MID TUESDAY MORNING AND MID
TUESDAY AFTERNOON. AFTER THAT TIME...THE STEADIEST RAINS WILL
QUICKLY TAPER OFF FROM WEST TO EAST BETWEEN LATE TUESDAY AFTERNOON
AND TUESDAY EVENING WITH THE PASSAGE OF THE TRAILING COLD FRONT...
WITH THE BACK EDGE OF THIS NOW APPEARING LIKELY TO EXIT OUR EASTERN
ZONES BETWEEN 03Z AND 06Z WEDNESDAY.
IN THE WAKE OF THE TRAILING COLD FRONT...A WEST-NORTHWESTERLY FLOW
OF MUCH COOLER AIR WILL FLOOD ACROSS THE REGION LATER TUESDAY AND
TUESDAY NIGHT...WITH 850 MB TEMPS PLUNGING TO BETWEEN 0C AND +3C BY
WEDNESDAY MORNING...THEN REMAINING AT THESE LEVELS RIGHT THROUGH
WEDNESDAY. WITH LAKE SURFACE TEMPS STILL RUNNING AROUND 21C...THIS
WILL BE PLENTY COLD ENOUGH TO SET OFF A LAKE RESPONSE...HOWEVER
MOISTURE WILL ONCE AGAIN BE A BIG LIMITING FACTOR THANKS TO
PLENTIFUL DRY AIR AND SUBSIDENCE ADVECTING IN BEHIND THE DEPARTING
LOW/COLD FRONT. WITH THE BULK OF ANY MOISTURE CONFINED TO 5-6 KFT OR
BELOW...WILL ONLY INDICATE SOME LINGERING LOWER-END CHANCE POPS
EAST-SOUTHEAST OF THE LAKES TUESDAY NIGHT...WITH ANY SCATTERED LAKE
EFFECT RAIN SHOWERS THEN FALLING APART ALTOGETHER ON WEDNESDAY WITH
DIURNAL INFLUENCES...AND AS HIGH PRESSURE BUILDS DIRECTLY OVERHEAD
ALONG WITH FURTHER DRYING AND INCREASING SUBSIDENCE. AFTER
THAT...DRY AND QUIET WEATHER IS EXPECTED TO CONTINUE THROUGH
WEDNESDAY NIGHT WITH THE AXIS OF THE AFOREMENTIONED SURFACE RIDGE
REMAINING PARKED DIRECTLY OVERHEAD.
WITH REGARD TO TEMPERATURES...FOLLOWING HIGHS IN THE MID 60S TO
LOWER 70S ON TUESDAY...EXPECT A SHARP COOLDOWN FOR THE REMAINDER
OF THE PERIOD GIVEN THE STRONG COLD AIR ADVECTION PATTERN BEHIND
THE DEPARTING LOW. EXPECT LOWS TO FALL BACK TO THE MID TO UPPER
40S TUESDAY NIGHT...WITH DAYTIME HIGHS ON WEDNESDAY THEN BARELY
REACHING 60 OR SO ACROSS THE LOWER ELEVATIONS...AND LIKELY NOT
MAKING IT OUT OF THE UPPER 50S ACROSS THE HIGHER TERRAIN. EVEN
COOLER READINGS IN THE LOWER TO MID 40S WILL THEN FOLLOW FOR
WEDNESDAY NIGHT...WITH UPPER 30S FOUND ACROSS INTERIOR PORTIONS OF
THE SOUTHERN TIER AND NORTH COUNTRY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE FIRST HALF OF THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A
LINGERING BROAD/FLAT TROUGH OVER EASTERN NORTH AMERICA RELOADING TO
OUR WEST...AS ANOTHER STRONG SHORTWAVE TROUGH PLUNGES SOUTHEASTWARD
ACROSS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. OUT AHEAD OF
THIS SHORTWAVE...THE PREVAILING SYNOPTIC-SCALE FLOW WILL AGAIN TURN
SOUTHWESTERLY...AND THIS WILL HELP TO TRANSPORT MUCH WARMER AIR BACK
INTO OUR REGION FOR A COUPLE OF DAYS. A BLEND OF THE 00Z GFS AND
ECMWF SUGGESTS 850 MB TEMPS RECOVERING TO BETWEEN +5C AND +8C
THURSDAY AND TO AROUND +11C/+12C FRIDAY...WHICH SHOULD BE ENOUGH TO
BOOST HIGH TEMPS BACK INTO THE 65-70 DEGREE RANGE ON THURSDAY...AND
AT LEAST THE LOWER TO MID 70S ON FRIDAY. THUS...WEDNESDAY`S SHARP
COOLDOWN WILL BE VERY BRIEF...WITH TEMPERATURES RECOVERING TO A BIT
ABOVE NORMAL LEVELS BY THE END OF THE WORK WEEK.
IN TERMS OF PRECIPITATION CHANCES...THE GFS AND ECMWF ARE NOW IN
BETTER AGREEMENT THAT THE VAST MAJORITY OF THE THURSDAY-FRIDAY TIME
FRAME SHOULD REMAIN DRY. BOTH MODELS WEAKEN AN INITIAL LEAD COLD
FRONT AS IT TRIES TO PRESS TOWARD OUR AREA ON THURSDAY...WITH THIS
FEATURE EVENTUALLY FALLING APART OVER SOUTHERN ONTARIO LATE THURSDAY
AND THURSDAY NIGHT. BOTH PACKAGES ALSO ARE NOW IN BETTER AGREEMENT
ON THE EVOLUTION OF A SUBSEQUENT SURFACE WAVE AND ASSOCIATED
STRONGER COLD FRONT...WITH THIS LATTER FEATURE ONLY APPROACHING
FAR WESTERN NEW YORK BY LATE FRIDAY AFTERNOON/FRIDAY EVENING. WITH
THE ABOVE IN MIND...HAVE KEPT PRECIP CHANCES FOR BOTH DAYS LARGELY
CONFINED TO SLIGHT CHANCE OR LESS...WITH ONLY SOME LOW CHANCE POPS
INDICATED ACROSS FAR WESTERN NEW YORK LATER FRIDAY AFTERNOON.
AFTER THAT...BOTH GUIDANCE PACKAGES DIG THE LARGE-SCALE UPPER TROUGH
DEEPER INTO THE CENTRAL AND EASTERN GREAT LAKES NEXT WEEKEND...WITH
THE AFOREMENTIONED SECOND COLD FRONT SLOWLY PUSHING ACROSS THE AREA
BETWEEN FRIDAY NIGHT AND SATURDAY...FOLLOWED BY A SECONDARY AND
WEAKER AREA OF LOW PRESSURE PASSING BY TO OUR NORTH ON SUNDAY. AT
THIS DISTANT JUNCTURE...THIS EVOLUTION IN THE PATTERN WILL SUPPORT
SOME BROADBRUSH LOWER-END SHOWER CHANCES BOTH DAYS...ALONG WITH A
TREND TOWARD PROGRESSIVELY COOLER TEMPERATURES AS THE COLD POOL
ASSOCIATED WITH THE UPPER LOW OVERSPREADS OUR REGION.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE CENTERED ALONG THE MID ATLANTIC COAST WILL KEEP FAIR
VFR WEATHER IN PLACE OVER OUR REGION THROUGH THE FIRST HALF OF
TONIGHT...ALTHOUGH THERE COULD BE ANOTHER HOUR OR TWO OF MVFR VSBYS
IN EARLY MORNING FOG FOR SITES SUCH AS KJHW AND KELZ.
DURING THE COURSE OF TONIGHT THOUGH...A COMPLEX STORM SYSTEM WILL
TAKE SHAPE OVER THE UPPER OHIO VALLEY AND SPREAD RAIN AND GENERALLY
DETERIORATING CONDITIONS NORTHWARDS. IFR CONDITIONS WILL DEVELOP
OVER THE WESTERN SOUTHERN TIER WITH MVFR VSBYS/CIGS POSSIBLE FOR THE
REMAINDER OF THE WRN COUNTIES.
OUTLOOK...
TUESDAY AND TUESDAY NIGHT...MVFR/IFR WITH RAIN. LLWS.
WEDNESDAY...IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
&&
.MARINE...
WHILE HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST SHOULD
KEEP CONDITIONS BELOW SMALL CRAFT ADVISORY CRITERIA TODAY...WATERS
WILL BE QUITE CHOPPY ACROSS THE EASTERN PART OF LAKE ONTARIO THIS
MORNING AND THEN OVER PARTS OF LAKE ERIE DURING THE MIDDAY AND EARLY
AFTERNOON. IN THOSE AREAS...MODERATE SOUTHERLIES WILL PRODUCE WAVES
OF 2 TO 4 FEET SO THEY WILL HAVE TO BE CLOSELY WATCHED.
WINDS AND WAVES WILL BRIEFLY SUBSIDE ON BOTH LAKES THIS EVENING...
THEN A COMPLEX STORM SYSTEM WILL APPROACH THE LOWER GREAT LAKES
DURING THE OVERNIGHT. WINDS AHEAD OF THIS STORM SYSTEM WILL FRESHEN
OVER EASTERN LAKE ONTARIO LATER TONIGHT...POSSIBLY PRODUCING SCA
CONDITIONS BY DAYBREAK TUESDAY.
STRONGER WINDS ARE EXPECTED IN THE WAKE OF THE STORM SYSTEM TUESDAY
AFTERNOON AND NIGHT WITH FRESH WEST TO NORTHWEST BREEZES PRODUCING
SCA CONDITIONS ACROSS MUCH OF LAKE ONTARIO AND POSSIBLY FOR A SHORT
TIME...ON LAKE ERIE.
HIGH PRESSURE WILL MOVE IN ON WEDNESDAY TO PROMOTE WEAKER WINDS AND
LOWER WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...RSH
MARINE...RSH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1000 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL SLIP OFFSHORE TODAY...AS A COLD FRONT APPROACHES
FROM THE WEST. THE FRONT WILL BRING SHOWERS AND THUNDERSTORMS TO THE
CAROLINAS TUESDAY...AND SOME STORMS MAY BE SEVERE. THE COLD FRONT
WILL LINGER NEAR THE COAST WEDNESDAY...BEFORE HIGH PRESSURE PUSHES
COOLER AND DRIER WEATHER INTO THE AREA THURSDAY AND FRIDAY. WEAK
HIGH PRESSURE WILL HOLD OVER THE REGION INTO NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM MONDAY...A WEAK WEST TO EAST BOUNDARY WAS POSITIONED
ACROSS OUR VERY NORTHERN TIER...AND THIS FEATURE WILL TRANSITION TO
A NORTHWARD LIFTING WARM FRONT THROUGH THE DAY AND TONIGHT. THIS
WILL LEAVE OUR FORECAST AREA IN AN UNSTABLE WARM SECTOR TODAY. THIS
SHOULD ALLOW AN ERUPTION OF ISOLATED TO SCATTERED SHOWERS AND TSTMS
THIS AFTERNOON. GIVEN THAT PLENTY SUNSHINE APPEARS IN THE CARDS FOR
TODAY...BELIEVE THE SEA BREEZE FRONT WILL PLAY A ROLE IN CONVECTIVE
INITIATION AND COULD FOCUS STRONGER STORMS INLAND THROUGH THE AFTN
HOURS. LOSS OF HEATING WILL WEAKEN CONVECTION IN THE EARLY EVENING
AND THE BULK OF ACTIVITY MAY HAVE CLEARED OR CLUSTERED STORMS OVER
OUR FAR INLAND AREAS LATE IN THE AFTERNOON TO EARLY EVENING.
TONIGHT A TAP OF GULF AND ATLANTIC MOISTURE WILL INCREASE PWAT
VALUES ABOVE 2 INCHES WITH INCREASING SOUTHERLY FLOW AHEAD OF AN
ENERGETIC UPPER TROUGH. FAVORABLE LOW-LEVEL HODOGRAPHS OVERNIGHT
MAY LEAD TO A FEW ROTATING TSTMS MOVING ONSHORE...MAINLY FROM
MIDNIGHT THROUGH EARLY TUESDAY MORNING.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG COLD FRONT STILL PROGGED TO CROSS THE
AREA TUESDAY BRINGING WIDESPREAD SHOWERS/TSTMS...POTENTIALLY WITH
DAMAGING WINDS AND HEAVY RAIN TO THE AREA...IN AN EARLY SEASON
HIGH SHEAR LOW CAPE EVENT.
PHASING OCCURRING AT 500MB TUESDAY BETWEEN SOUTHERN AND NORTHERN
STREAM IMPULSES CREATES A HIGHLY AMPLIFIED TROUGH ACROSS THE EASTERN
CONUS. SURFACE LOW RIDES UP THE APPALACHIANS AND DRIVES A COLD ACROSS
THE CAROLINAS. STRONG LOW LEVEL WINDS...APPROACHING 50 KTS AT
850MB...ADVECT COPIOUS MOISTURE INTO THE COLUMN AND STRONG MID-LEVEL
THETA-E ADVECTION OCCURS AHEAD OF THIS FRONT. SPC HAS PLACED THE
ENTIRE AREA IN A SLIGHT RISK FOR TUESDAY...30% PROBABILITIES ACROSS
THE I-95 COUNTIES...AND THIS SEEMS WARRANTED BASED OFF THE STRONG
LOW LEVEL WIND FIELDS.
DO NOT EXPECT WIDESPREAD SEVERE WINDS TUESDAY...BUT ISOLATED TO
POTENTIALLY SCATTERED DAMAGING WIND GUSTS ARE POSSIBLE. 0-6KM BULK
SHEAR RISES TO AROUND 30 KTS WHICH COULD SUPPORT MULTICELL CLUSTERS
WITH STRONG WINDS IN A UNIDIRECTIONAL SHEAR ENVIRONMENT...AND
FORECAST SBCAPE RISES TO AROUND 1000 J/KG AHEAD OF THE FRONT.
HOWEVER...DCAPE IS MINIMAL...UPPER FORCING LAGS BEHIND THE BEST
SURFACE DYNAMICS...AND FRONT ITSELF WILL CROSS DURING THE NIGHTTIME
HOURS...ALTHOUGH WITH STRONG THETA-E ADVECTION OCCURRING RIGHT UP
UNTIL FROPA...CONVECTION MAY SUSTAIN ITSELF WELL PAST NIGHTFALL.
SO...CANNOT RULE OUT A FEW DAMAGING WIND GUSTS...ESPECIALLY SINCE
SUSTAINED GRADIENT WINDS WILL LIKELY BE AROUND 20 MPH TO BEGIN
WITH...AND IT WILL NOT TAKE AN INCREDIBLY STRONG STORM TO MIX DOWN
THE LLJ WINDS. STILL...DO NOT ANTICIPATE A WIDESPREAD SEVERE WEATHER
EVENT IN THE ILM CWA...SINCE BEST COMBINATION OF FORCING SHOULD BE
DISPLACED NW OF THIS AREA. HEAVY RAIN ON THE OTHER HAND WILL BE THE
MORE SIGNIFICANT THREAT...WITH TORRENTIAL RAINFALL LIKELY IN
CONVECTION.
FRONT CROSSES THE AREA VERY EARLY WEDNESDAY...BUT INDICATIONS ARE
NOW THAT IT WILL HANG BACK NEAR THE COAST AS A SECONDARY LOW
DEVELOPS ACROSS THE SOUTHEAST AND UPPER TROUGHING LAGS BEHIND. THIS
WILL KEEP PRECIP CHANCES THROUGHOUT THE SHORT TERM...ALTHOUGH MUCH
LIGHTER QPF EXPECTED WEDNESDAY...HIGHEST NEAR THE COAST.
FORECAST PROFILES SUGGEST A WEAK WEDGE SCENARIO (RARE FOR THIS EARLY
IN THE SEASON) DEVELOPING WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES
DOWN THE COAST WHILE SW FLOW REMAINS ABOVE 900MB. THIS SUGGESTS SOME
LIGHT RAIN OR EVEN DRIZZLE POTENTIALLY PERSISTING THROUGH THE END OF
THE PERIOD. VERY DRY AIR ABOVE THE WEDGE...PLUS THIS BEING OUT OF
SEASON...MEANS THAT ONLY SCHC POP WILL BE CONTINUED THROUGH THE END
OF THE SHORT TERM BUT CLOUD COVER SHOULD BE PRETTY
SIGNIFICANT...ESPECIALLY NEAR THE COAST.
HIGH TEMPS TUESDAY WILL BE RIGHT AROUND CLIMO...LOW 80S...AS STRONG
WAA IS COUNTERACTED BY CLOUD COVER AND SHOWERS...WHILE NIGHTTIME
MINS WILL BE HELD WELL ABOVE NORMAL...ONLY FALLING TO THE UPPER
60S/LOW 70S. WEDNESDAY WILL BE COOLER BEHIND THE FRONT...AROUND 80
FOR HIGHS AND NEAR 60 FOR LOWS AWAY FROM THE IMMEDIATE COAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...FRONT HOVERING JUST OFFSHORE MAY ALLOW FOR
CONTINUED SHOWERS NEAR THE COAST ON THURSDAY. FORECAST PROFILES DRY
OUT CONSIDERABLY HOWEVER...AND WILL DROP INHERITED CHC TO JUST SCHC
ON THE COAST...SILENT INLAND. BEST CHANCE WILL BE DURING THE EARLY
PART OF THE DAY BEFORE HIGH PRESSURE MORE FIRMLY RIDGES DOWN THE
COAST FORCING THE FRONT FURTHER OFFSHORE. OTHERWISE...THE EXTENDED
FEATURES DRY AND SEASONABLE WEATHER AS HIGH PRESSURE DOMINATES AT
THE SURFACE AND A LARGE UPPER TROUGH PERSISTS OVER THE EASTERN HALF
OF THE COUNTRY. ONLY FEATURE OF INTEREST IS A COLD FRONT WHICH WILL
TRY TO CROSS INTO THE AREA ON SATURDAY. WITH UPPER TROUGH RELOADING
ACROSS THE GREAT LAKES...MID LEVEL WINDS WILL REMAIN OUT OF THE WSW
WHICH WILL INHIBIT THIS FRONT FROM MAKING ANY NOTICEABLE IMPACT TO
THIS AREA...AND ANY COOLER AIR AND/OR PRECIP WILL BE DISPLACED NORTH
OF THE CWA.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
AS OF 14Z...MODELS ARE NOT IN GOOD AGREEMENT WITH PRECIPITATION
TODAY...AT ALL. NAM IS VERY BULLISH WITH PRECIPITATION ON AND OFF
FOR MOST OF THE NEXT 24 HOURS...WHILE THE GFS HAS HARDLY ANY THING
AT ALL. THE HRRR HAS THE PRECIPITATION WEST OF LBT WEAKENING OVER
THE NEXT FEW HOURS. THE WRF SEEMS TO BE THE MOST REASONABLE...WITH
SCATTERED CONVECTION FIRING NEAR THE COAST AND WORKING NORTHWEST
OVER TIME. THE MVFR CEILINGS ARE FEW AND FAR BETWEEN...SO WENT WITH
MAINLY VFR THIS MORNING. AS THE WARM FRONT LIFTS NORTHWARD...WINDS
WILL INCREASE AND BECOME MORE SOUTHERLY THROUGH TIME. TONIGHT...DEEP
MOISTURE APPROACHES OUT AHEAD OF A DEEPENING LOW. LOOK FOR MODERATE
TO HEAVY PRECIP TO MOVE INTO THE WESTERN TERMINALS TOWARD THE END OF
THE FORECAST PERIOD...WITH ONLY ISOLATED ACTIVITY ALONG THE COAST.
IFR CONDITIONS ARE POSSIBLE INLAND...BUT SHOULD BE PREDOMINATELY
MVFR.
THE EXTENDED OUTLOOK...SHRA/TSRA ON TUESDAY WITH MODERATE
CONFIDENCE FOR INTERMITTENT IFR CONDITIONS. CONVECTION WILL
CONTINUE INTO WEDNESDAY WITH IMPROVING CONDITIONS THURSDAY INTO
SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM MONDAY...SCA ALL WATERS FOR LATE TONIGHT. SE-S WINDS 10
KT...WILL BECOME SOUTHERLY 10-15 KT THIS AFTERNOON...THEN 15 TO 20
KT TONIGHT AHEAD OF AN APPROACHING SURFACE COLD FRONT FROM THE WEST.
SIGNIFICANT SEAS INITIALLY 2 TO 4 FT...WILL BUILD TO 4 TO 6 FT
ACROSS THE WATERS BY DAYBREAK TUESDAY.
WIND FIELDS SEVERAL HUNDRED FEET OFF THE SURFACE WILL REACH 40 KT
AFTER MIDNIGHT TONIGHT. AS A RESULT...CONVECTION THAT TRAVERSES THE
ILM WATERS WILL TAP INTO THESE HIGHER WINDS AND POTENTIALLY DROP
THEM TO THE OCEAN SFC WITH STRONG WIND GUSTS. FAVORABLE LOW-LEVEL
WIND SHEAR/HODOGRAPHS WILL FAVOR ROTATING OR STRONG TSTMS LATE
TONIGHT INTO EARLY TUESDAY.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG SOUTHERLY WINDS AHEAD OF A POTENT COLD
FRONT WILL CREATE SMALL CRAFT ADVISORY CONDITIONS THROUGH MUCH OF
TUESDAY. WINDS OF 15-25 KTS WILL HELP BUILD SEAS TO 4-6 FT...HIGHEST
ACROSS THE NORTHERN WATERS. WAVES WILL BE FORMED BY A COMBINATION OF
A WEAK SE SWELL AND THE MORE DOMINANT 6 SEC SOUTHERLY WIND
WAVES...SO EXPECT RELATIVELY STEEP WAVE FACES THROUGH THE DAY.
ADDITIONALLY...STRONG THUNDERSTORMS ARE POSSIBLE AHEAD OF THE COLD
FRONT AS IT ADVANCES EASTWARD THROUGH THE EVENING. THESE STORMS
COULD PRODUCE MUCH STRONGER WIND GUSTS AND TORRENTIAL RAINFALL...AS
WELL AS LOCALLY ENHANCED WAVE HEIGHTS.
WINDS TURN WESTERLY EARLY WEDNESDAY WITH THE FRONT AND THEN BECOME
LIGHT AND VARIABLE AS THE BOUNDARY WAVERS OVER THE COASTAL WATERS.
BY LATE WEDNESDAY WINDS WILL BECOME NE...BUT REMAIN LESS THAN 10
KTS. SEAS FALL QUICKLY DURING THE DAY...FROM 3-5 FT EARLY TO 2-3 FT
LATE...THANKS TO THE EASING WIND SPEEDS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...HIGH PRESSURE RIDGES DOWN THE COAST THURSDAY
BEFORE DRIFTING OFFSHORE FRIDAY. NE WINDS OF AROUND 10 KTS PERSIST
MUCH OF THURSDAY BEFORE THE GRADIENT RELAXES...ALLOWING WINDS TO
BECOME LIGHT AND VARIABLE FRIDAY...BEFORE FINALLY TURNING TO THE SE
AT THE END OF THE PERIOD. WAVE GUIDANCE SHOWS SEVERAL DIFFERENT WAVE
GROUPS PRESENT IN THE SPECTRUM THROUGH THE EXTENDED...WITH NO GROUP
BECOMING DOMINANT. WITHOUT ANY MEANINGFUL SWELL OR PRESSURE
GRADIENT...SEAS WILL BE 1-3 FT THURSDAY...AND ONLY 1-2 FT ON FRIDAY.
&&
.TIDES/COASTAL FLOODING...
AS OF 350 AM MONDAY...BETWEEN 10 AM AND NOON TODAY...PROGGED MDL
WILMINGTON TIDE GAGE FORECASTS INDICATE A THREAT FOR GAGE READINGS
ABOVE THE 5.50 FT MLLW COASTAL FLOOD ADVISORY THRESHOLD BETWEEN 10
AM AND NOON TODAY. A PEAK OF 5.60 FT MLLW IS FORECAST AROUND 11
AM. THE PRONE LOCATIONS TO THIS TYPE OF SHALLOW FLOODING WILL
INCLUDE AREAS BORDERING ALONG THE CAPE FEAR RIVER SUCH AS WATER
STREET OF DOWNTOWN WILMINGTON... ROADWAYS LEADING TO AND FROM THE
USS NORTH CAROLINA BATTLESHIP... AND CANAL ROAD IN CAROLINA BEACH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 10 AM THIS MORNING TO NOON EDT
TODAY FOR NCZ107-108.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 5 AM EDT WEDNESDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...8
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...43
TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
716 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL DRIFT OFF THE CAROLINA COASTS TODAY AS A COLD
FRONT APPROACHES FROM THE WEST. LOW PRESSURE WILL MOVE THROUGH THE
WESTERN CAROLINAS TUESDAY...DRAGGING A STRONG COLD FRONT ACROSS
THE AREA. THIS COLD FRONT WILL PRODUCE WIDESPREAD SHOWERS AND
THUNDERSTORMS...SOME OF WHICH COULD BE STRONG. COLD FRONT WILL
LINGER NEAR THE COAST WEDNESDAY...BEFORE HIGH PRESSURE BRINGS
COOLER AND DRIER WEATHER INTO THE AREA FOR LATE WEEK AND THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 640 AM MONDAY...SFC WIND FIELD VIA LATEST HRRR INDICATES A
SFC BOUNDARY LYING ACROSS THE FA THIS MORNING...WHICH SHOULD
TRANSITION INTO A WARM FRONT AND LIFT NORTH OF THE FA MIDDAY
THROUGH THIS AFTERNOON. THE BEST SYNOPTIC LIFT UVVS WILL LIE ALONG
AND NORTH OF THIS BOUNDARY...MUCH OF THE UVVS COMING FROM THE
DYNAMICS ASSOCIATED WITH WEAK MID-LEVEL S/W TROFS/IMPULSES MOVING
EASTWARD ACROSS THE NORTHERN HALF OF NC. HAVE ADJUSTED THE HIGHER
POPS MAINLY ALONG AND NORTH OF THE ILM NC-SC BORDER FOR TODAY.
VIA VARIOUS MODEL TIME HEIGHT SECTIONS ACROSS THE FA...MID AND
HIGH LEVEL CLOUDS WILL BLANKET MUCH OF THE AREA TODAY. THIS IN
TURN WILL BLOCK A GOOD AMOUNT OF THE DAYS INSOLATION...RESULTING
WITH BORDERLINE WEAK INSTABILITY FOR CONVECTION. MAXES TO RANGE
FROM AROUND 80 NORTHERN PORTIONS...TO THE MID 80S SOUTHERN
PORTIONS.
FOR TONIGHT...THE MID AND UPPER LEVEL RIDGE AXIS MOVES OFF THE
COAST ALLOWING THE MID LEVEL S/W TROF ALONG THE US NW GULF COAST
TO TRACK EASTWARD...AND BEGIN TO PHASE WITH THE EXPANDING AND
DEEPENING HUDSON BAY/GREAT LAKES MID-UPPER LEVEL TROF. EARLY THIS
EVENING...SFC THRU 8H FLOW WILL HAVE TAPPED BOTH ATLANTIC AND GULF
OF MEXICO MOISTURE. AFTER MIDNIGHT...FLOW ABOVE 7H WILL HAVE
FURTHER TAPPED GULF OF MEXICO AND EVENTUALLY ATLANTIC MOISTURE
BY DAYBREAK. LOOK FOR MODEL PROGGED SOUNDING PWS TO EASILY
SURPASS 2.00 INCHES OVERNIGHT. WILL INDICATE INCREASING POPS DURING
TONIGHT...WITH HEAVY RAIN POSSIBLE FROM ANY CONVECTION. LOOK FOR A
SOMEWHAT FAVORABLE LOW LEVEL HODOGRAPHS FOR ONSHORE MOVEMENT OF
ROTATING THUNDERSTORMS BETWEEN MIDNIGHT TONIGHT TO UP TO SEVERAL
HRS AFTER DAYBREAK TUESDAY. ISOLATED CONVECTION THAT MOVES ONSHORE
LATE TONIGHT WILL BE THE ACTIVITY SUSCEPTIBLE TO PRODUCE THE
ISOLATED WATERSPOUT/TORNADO AS WELL AS DAMAGING WIND GUSTS. HAVE
PLACED ITS REMOTE POSSIBILITY WITHIN THE HWO. DECENT WAA TONIGHT
UNDER DEVELOPING STRONG ONSHORE SOUTHERLY WINDS...WILL PRODUCE MIN
TEMPS IN THE 70S THRU OUT THE FA.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG COLD FRONT STILL PROGGED TO CROSS THE
AREA TUESDAY BRINGING WIDESPREAD SHOWERS/TSTMS...POTENTIALLY WITH
DAMAGING WINDS AND HEAVY RAIN TO THE AREA...IN AN EARLY SEASON
HIGH SHEAR LOW CAPE EVENT.
PHASING OCCURRING AT 500MB TUESDAY BETWEEN SOUTHERN AND NORTHERN
STREAM IMPULSES CREATES A HIGHLY AMPLIFIED TROUGH ACROSS THE EASTERN
CONUS. SURFACE LOW RIDES UP THE APPALACHIANS AND DRIVES A COLD ACROSS
THE CAROLINAS. STRONG LOW LEVEL WINDS...APPROACHING 50 KTS AT
850MB...ADVECT COPIOUS MOISTURE INTO THE COLUMN AND STRONG MID-LEVEL
THETA-E ADVECTION OCCURS AHEAD OF THIS FRONT. SPC HAS PLACED THE
ENTIRE AREA IN A SLIGHT RISK FOR TUESDAY...30% PROBABILITIES ACROSS
THE I-95 COUNTIES...AND THIS SEEMS WARRANTED BASED OFF THE STRONG
LOW LEVEL WIND FIELDS.
DO NOT EXPECT WIDESPREAD SEVERE WINDS TUESDAY...BUT ISOLATED TO
POTENTIALLY SCATTERED DAMAGING WIND GUSTS ARE POSSIBLE. 0-6KM BULK
SHEAR RISES TO AROUND 30 KTS WHICH COULD SUPPORT MULTICELL CLUSTERS
WITH STRONG WINDS IN A UNIDIRECTIONAL SHEAR ENVIRONMENT...AND
FORECAST SBCAPE RISES TO AROUND 1000 J/KG AHEAD OF THE FRONT.
HOWEVER...DCAPE IS MINIMAL...UPPER FORCING LAGS BEHIND THE BEST
SURFACE DYNAMICS...AND FRONT ITSELF WILL CROSS DURING THE NIGHTTIME
HOURS...ALTHOUGH WITH STRONG THETA-E ADVECTION OCCURRING RIGHT UP
UNTIL FROPA...CONVECTION MAY SUSTAIN ITSELF WELL PAST NIGHTFALL.
SO...CANNOT RULE OUT A FEW DAMAGING WIND GUSTS...ESPECIALLY SINCE
SUSTAINED GRADIENT WINDS WILL LIKELY BE AROUND 20 MPH TO BEGIN
WITH...AND IT WILL NOT TAKE AN INCREDIBLY STRONG STORM TO MIX DOWN
THE LLJ WINDS. STILL...DO NOT ANTICIPATE A WIDESPREAD SEVERE WEATHER
EVENT IN THE ILM CWA...SINCE BEST COMBINATION OF FORCING SHOULD BE
DISPLACED NW OF THIS AREA. HEAVY RAIN ON THE OTHER HAND WILL BE THE
MORE SIGNIFICANT THREAT...WITH TORRENTIAL RAINFALL LIKELY IN
CONVECTION.
FRONT CROSSES THE AREA VERY EARLY WEDNESDAY...BUT INDICATIONS ARE
NOW THAT IT WILL HANG BACK NEAR THE COAST AS A SECONDARY LOW
DEVELOPS ACROSS THE SOUTHEAST AND UPPER TROUGHING LAGS BEHIND. THIS
WILL KEEP PRECIP CHANCES THROUGHOUT THE SHORT TERM...ALTHOUGH MUCH
LIGHTER QPF EXPECTED WEDNESDAY...HIGHEST NEAR THE COAST.
FORECAST PROFILES SUGGEST A WEAK WEDGE SCENARIO (RARE FOR THIS EARLY
IN THE SEASON) DEVELOPING WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES
DOWN THE COAST WHILE SW FLOW REMAINS ABOVE 900MB. THIS SUGGESTS SOME
LIGHT RAIN OR EVEN DRIZZLE POTENTIALLY PERSISTING THROUGH THE END OF
THE PERIOD. VERY DRY AIR ABOVE THE WEDGE...PLUS THIS BEING OUT OF
SEASON...MEANS THAT ONLY SCHC POP WILL BE CONTINUED THROUGH THE END
OF THE SHORT TERM BUT CLOUD COVER SHOULD BE PRETTY
SIGNIFICANT...ESPECIALLY NEAR THE COAST.
HIGH TEMPS TUESDAY WILL BE RIGHT AROUND CLIMO...LOW 80S...AS STRONG
WAA IS COUNTERACTED BY CLOUD COVER AND SHOWERS...WHILE NIGHTTIME
MINS WILL BE HELD WELL ABOVE NORMAL...ONLY FALLING TO THE UPPER
60S/LOW 70S. WEDNESDAY WILL BE COOLER BEHIND THE FRONT...AROUND 80
FOR HIGHS AND NEAR 60 FOR LOWS AWAY FROM THE IMMEDIATE COAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...FRONT HOVERING JUST OFFSHORE MAY ALLOW FOR
CONTINUED SHOWERS NEAR THE COAST ON THURSDAY. FORECAST PROFILES DRY
OUT CONSIDERABLY HOWEVER...AND WILL DROP INHERITED CHC TO JUST SCHC
ON THE COAST...SILENT INLAND. BEST CHANCE WILL BE DURING THE EARLY
PART OF THE DAY BEFORE HIGH PRESSURE MORE FIRMLY RIDGES DOWN THE
COAST FORCING THE FRONT FURTHER OFFSHORE. OTHERWISE...THE EXTENDED
FEATURES DRY AND SEASONABLE WEATHER AS HIGH PRESSURE DOMINATES AT
THE SURFACE AND A LARGE UPPER TROUGH PERSISTS OVER THE EASTERN HALF
OF THE COUNTRY. ONLY FEATURE OF INTEREST IS A COLD FRONT WHICH WILL
TRY TO CROSS INTO THE AREA ON SATURDAY. WITH UPPER TROUGH RELOADING
ACROSS THE GREAT LAKES...MID LEVEL WINDS WILL REMAIN OUT OF THE WSW
WHICH WILL INHIBIT THIS FRONT FROM MAKING ANY NOTICEABLE IMPACT TO
THIS AREA...AND ANY COOLER AIR AND/OR PRECIP WILL BE DISPLACED NORTH
OF THE CWA.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...MODELS ARE NOT IN GOOD AGREEMENT WITH PRECIPITATION
TODAY...AT ALL. NAM IS VERY BULLISH WITH PRECIPITATION ON AND OFF
FOR MOST OF THE NEXT 24 HOURS...WHILE THE GFS HAS HARDLY ANY THING
AT ALL. THE HRRR HAS THE PRECIPITATION WEST OF LBT WEAKENING OVER
THE NEXT FEW HOURS. THE WRF SEEMS TO BE THE MOST REASONABLE...WITH
SCATTERED CONVECTION FIRING NEAR THE COAST AND WORKING NORTHWEST
OVER TIME. THE MVFR CEILINGS ARE FEW AND FAR BETWEEN...SO WENT WITH
MAINLY VFR THIS MORNING. AS THE WARM FRONT LIFTS NORTHWARD...WINDS
WILL INCREASE AND BECOME MORE SOUTHERLY THROUGH TIME. TONIGHT...DEEP
MOISTURE APPROACHES OUT AHEAD OF A DEEPENING LOW. LOOK FOR MODERATE
TO HEAVY PRECIP TO MOVE INTO THE WESTERN TERMINALS TOWARD THE END OF
THE FORECAST PERIOD...WITH ONLY ISOLATED ACTIVITY ALONG THE COAST.
IFR CONDITIONS ARE POSSIBLE INLAND...BUT SHOULD BE PREDOMINATELY
MVFR.
THE EXTENDED OUTLOOK...SHRA/TSRA ON TUESDAY WITH MODERATE
CONFIDENCE FOR INTERMITTENT IFR CONDITIONS. CONVECTION WILL
CONTINUE INTO WEDNESDAY WITH IMPROVING CONDITIONS THURSDAY INTO
SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 640 AM MONDAY...SCA RAISED FOR ALL ILM WATERS FOR LATE
TONIGHT. SE-S WINDS 10 KT...WILL BECOME SOUTHERLY 10-15 KT BY THIS
AFTERNOON...AND FURTHER INCREASE TO 15 TO 20 KT TONIGHT. THIS IN
RESPONSE TO AN ORGANIZING SFC PRESSURE PATTERN...AND TIGHTENING SFC
PRESSURE GRADIENT DEVELOPING AHEAD OF THE APPROACHING SURFACE COLD
FRONT FROM THE WEST. SIGNIFICANT SEAS WILL INITIALLY COMMENCE AT 2
TO 4 FT...MAINLY COMPRISED OF A 10-12 SECOND SE SWELL. WITH
INCREASING WINDS LATER TODAY AND TONIGHT...LOCALLY PRODUCED WIND
DRIVEN WAVES AT 4 TO 7 SECOND AVERAGE PERIODS WILL BECOME MORE
DOMINANT. AT THIS POINT...SWAN ADVERTISES SIG. SEAS REACHING 4 TO
6 FT ACROSS ALL WATERS JUST PRIOR TO DAYBREAK TUE...HENCE HAVE
RAISED THE SCA. WIND FIELDS JUST OFF THE DECK ARE PROGGED TO
REACH 40 KT AFTER MIDNIGHT TONIGHT. AS A RESULT...CONVECTION THAT
TRAVERSES THE ILM WATERS WILL TAP INTO THESE HIGHER WINDS AND
POTENTIALLY DROP THEM TO THE OCEAN SFC AS WIND GUSTS 35 KT OR
GREATER. FAVORABLE LOW LEVEL WIND SHEAR AND HODOGRAPHS WILL AID
ISOLATED WATERSPOUT POSSIBILITIES...MAINLY BETWEEN MIDNIGHT AND UP
TO SEVERAL HOURS AFTER DAYBREAK TUE.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG SOUTHERLY WINDS AHEAD OF A POTENT COLD
FRONT WILL CREATE SMALL CRAFT ADVISORY CONDITIONS THROUGH MUCH OF
TUESDAY. WINDS OF 15-25 KTS WILL HELP BUILD SEAS TO 4-6 FT...HIGHEST
ACROSS THE NORTHERN WATERS. WAVES WILL BE FORMED BY A COMBINATION OF
A WEAK SE SWELL AND THE MORE DOMINANT 6 SEC SOUTHERLY WIND
WAVES...SO EXPECT RELATIVELY STEEP WAVE FACES THROUGH THE DAY.
ADDITIONALLY...STRONG THUNDERSTORMS ARE POSSIBLE AHEAD OF THE COLD
FRONT AS IT ADVANCES EASTWARD THROUGH THE EVENING. THESE STORMS
COULD PRODUCE MUCH STRONGER WIND GUSTS AND TORRENTIAL RAINFALL...AS
WELL AS LOCALLY ENHANCED WAVE HEIGHTS.
WINDS TURN WESTERLY EARLY WEDNESDAY WITH THE FRONT AND THEN BECOME
LIGHT AND VARIABLE AS THE BOUNDARY WAVERS OVER THE COASTAL WATERS.
BY LATE WEDNESDAY WINDS WILL BECOME NE...BUT REMAIN LESS THAN 10
KTS. SEAS FALL QUICKLY DURING THE DAY...FROM 3-5 FT EARLY TO 2-3 FT
LATE...THANKS TO THE EASING WIND SPEEDS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...HIGH PRESSURE RIDGES DOWN THE COAST THURSDAY
BEFORE DRIFTING OFFSHORE FRIDAY. NE WINDS OF AROUND 10 KTS PERSIST
MUCH OF THURSDAY BEFORE THE GRADIENT RELAXES...ALLOWING WINDS TO
BECOME LIGHT AND VARIABLE FRIDAY...BEFORE FINALLY TURNING TO THE SE
AT THE END OF THE PERIOD. WAVE GUIDANCE SHOWS SEVERAL DIFFERENT WAVE
GROUPS PRESENT IN THE SPECTRUM THROUGH THE EXTENDED...WITH NO GROUP
BECOMING DOMINANT. WITHOUT ANY MEANINGFUL SWELL OR PRESSURE
GRADIENT...SEAS WILL BE 1-3 FT THURSDAY...AND ONLY 1-2 FT ON FRIDAY.
&&
.TIDES/COASTAL FLOODING...
AS OF 350 AM MONDAY...BETWEEN 10 AM AND NOON TODAY...PROGGED MDL
WILMINGTON TIDE GAGE FORECASTS INDICATE A THREAT FOR GAGE READINGS
ABOVE THE 5.50 FT MLLW COASTAL FLOOD ADVISORY THRESHOLD BETWEEN 10
AM AND NOON TODAY. A PEAK OF 5.60 FT MLLW IS FORECAST AROUND 11
AM. THE PRONE LOCATIONS TO THIS TYPE OF SHALLOW FLOODING WILL
INCLUDE AREAS BORDERING ALONG THE CAPE FEAR RIVER SUCH AS WATER
STREET OF DOWNTOWN WILMINGTON... ROADWAYS LEADING TO AND FROM THE
USS NORTH CAROLINA BATTLESHIP... AND CANAL ROAD IN CAROLINA BEACH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 10 AM THIS MORNING TO NOON EDT
TODAY FOR NCZ107-108.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 5 AM EDT WEDNESDAY
FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DCH
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...43
TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
643 AM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL DRIFT OFF THE CAROLINA COASTS TODAY AS A COLD
FRONT APPROACHES FROM THE WEST. LOW PRESSURE WILL MOVE THROUGH THE
WESTERN CAROLINAS TUESDAY...DRAGGING A STRONG COLD FRONT ACROSS
THE AREA. THIS COLD FRONT WILL PRODUCE WIDESPREAD SHOWERS AND
THUNDERSTORMS...SOME OF WHICH COULD BE STRONG. COLD FRONT WILL
LINGER NEAR THE COAST WEDNESDAY...BEFORE HIGH PRESSURE BRINGS
COOLER AND DRIER WEATHER INTO THE AREA FOR LATE WEEK AND THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 640 AM MONDAY...SFC WIND FIELD VIA LATEST HRRR INDICATES A
SFC BOUNDARY LYING ACROSS THE FA THIS MORNING...WHICH SHOULD
TRANSITION INTO A WARM FRONT AND LIFT NORTH OF THE FA MIDDAY
THROUGH THIS AFTERNOON. THE BEST SYNOPTIC LIFT UVVS WILL LIE ALONG
AND NORTH OF THIS BOUNDARY...MUCH OF THE UVVS COMING FROM THE
DYNAMICS ASSOCIATED WITH WEAK MID-LEVEL S/W TROFS/IMPULSES MOVING
EASTWARD ACROSS THE NORTHERN HALF OF NC. HAVE ADJUSTED THE HIER
POPS MAINLY ALONG AND NORTH OF THE ILM NC-SC BORDER FOR TODAY.
VIA VARIOUS MODEL TIME HEIGHT SECTIONS ACROSS THE FA...MID AND
HIGH LEVEL CLOUDS WILL BLANKET MUCH OF THE AREA TODAY. THIS IN
TURN WILL BLOCK A GOOD AMOUNT OF THE DAYS INSOLATION...RESULTING
WITH BORDERLINE WEAK INSTABILITY FOR CONVECTION. MAXES TO RANGE
FROM AROUND 80 NORTHERN PORTIONS...TO THE MID 80S SOUTHERN
PORTIONS.
FOR TONIGHT...THE MID AND UPPER LEVEL RIDGE AXIS MOVES OFF THE
COAST ALLOWING THE MID LEVEL S/W TROF ALONG THE US NW GULF COAST
TO TRACK EASTWARD...AND BEGIN TO PHASE WITH THE EXPANDING AND
DEEPENING HUDSON BAY/GREAT LAKES MID-UPPER LEVEL TROF. EARLY THIS
EVENING...SFC THRU 8H FLOW WILL HAVE TAPPED BOTH ATLANTIC AND GULF
OF MEXICO MOISTURE. AFTER MIDNIGHT...FLOW ABOVE 7H WILL HAVE
FURTHER TAPPED GULF OF MEXICO AND EVENTUALLY ATLANTIC MOISTURE
BY DAYBREAK. LOOK FOR MODEL PROGGED SOUNDING PWS TO EASILY
SURPASS 2.00 INCHES OVERNIGHT. WILL INDICATE INCREASING POPS DURING
TONIGHT...WITH HEAVY RAIN POSSIBLE FROM ANY CONVECTION. LOOK FOR A
SOMEWHAT FAVORABLE LOW LEVEL HODOGRAPH FOR ONSHORE MOVEMENT OF
ROTATING THUNDERSTORMS BETWEEN MIDNIGHT TONIGHT TO UP TO SEVERAL
HRS AFTER DAYBREAK TUESDAY. ISOLATED CONVECTION THAT MOVES ONSHORE
LATE TONIGHT WILL BE THE ACTIVITY SUSCEPTIBLE TO PRODUCE THE
ISOLATED WATERSPOUT/TORNADO AS WELL AS DAMAGING WIND GUSTS. HAVE
PLACED ITS REMOTE POSSIBILITY WITHIN THE HWO. DECENT WAA TONIGHT
UNDER DEVELOPING STRONG ONSHORE SOUTHERLY WINDS...WILL PRODUCE MIN
TEMPS IN THE 70S THRU OUT THE FA.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG COLD FRONT STILL PROGGED TO CROSS THE
AREA TUESDAY BRINGING WIDESPREAD SHOWERS/TSTMS...POTENTIALLY WITH
DAMAGING WINDS AND HEAVY RAIN TO THE AREA...IN AN EARLY SEASON
HIGH SHEAR LOW CAPE EVENT.
PHASING OCCURRING AT 500MB TUESDAY BETWEEN SOUTHERN AND NORTHERN
STREAM IMPULSES CREATES A HIGHLY AMPLIFIED TROUGH ACROSS THE EASTERN
CONUS. SURFACE LOW RIDES UP THE APPALACHIANS AND DRIVES A COLD ACROSS
THE CAROLINAS. STRONG LOW LEVEL WINDS...APPROACHING 50 KTS AT
850MB...ADVECT COPIOUS MOISTURE INTO THE COLUMN AND STRONG MID-LEVEL
THETA-E ADVECTION OCCURS AHEAD OF THIS FRONT. SPC HAS PLACED THE
ENTIRE AREA IN A SLIGHT RISK FOR TUESDAY...30% PROBABILITIES ACROSS
THE I-95 COUNTIES...AND THIS SEEMS WARRANTED BASED OFF THE STRONG
LOW LEVEL WIND FIELDS.
DO NOT EXPECT WIDESPREAD SEVERE WINDS TUESDAY...BUT ISOLATED TO
POTENTIALLY SCATTERED DAMAGING WIND GUSTS ARE POSSIBLE. 0-6KM BULK
SHEAR RISES TO AROUND 30 KTS WHICH COULD SUPPORT MULTICELL CLUSTERS
WITH STRONG WINDS IN A UNIDIRECTIONAL SHEAR ENVIRONMENT...AND
FORECAST SBCAPE RISES TO AROUND 1000 J/KG AHEAD OF THE FRONT.
HOWEVER...DCAPE IS MINIMAL...UPPER FORCING LAGS BEHIND THE BEST
SURFACE DYNAMICS...AND FRONT ITSELF WILL CROSS DURING THE NIGHTTIME
HOURS...ALTHOUGH WITH STRONG THETA-E ADVECTION OCCURRING RIGHT UP
UNTIL FROPA...CONVECTION MAY SUSTAIN ITSELF WELL PAST NIGHTFALL.
SO...CANNOT RULE OUT A FEW DAMAGING WIND GUSTS...ESPECIALLY SINCE
SUSTAINED GRADIENT WINDS WILL LIKELY BE AROUND 20 MPH TO BEGIN
WITH...AND IT WILL NOT TAKE AN INCREDIBLY STRONG STORM TO MIX DOWN
THE LLJ WINDS. STILL...DO NOT ANTICIPATE A WIDESPREAD SEVERE WEATHER
EVENT IN THE ILM CWA...SINCE BEST COMBINATION OF FORCING SHOULD BE
DISPLACED NW OF THIS AREA. HEAVY RAIN ON THE OTHER HAND WILL BE THE
MORE SIGNIFICANT THREAT...WITH TORRENTIAL RAINFALL LIKELY IN
CONVECTION.
FRONT CROSSES THE AREA VERY EARLY WEDNESDAY...BUT INDICATIONS ARE
NOW THAT IT WILL HANG BACK NEAR THE COAST AS A SECONDARY LOW
DEVELOPS ACROSS THE SOUTHEAST AND UPPER TROUGHING LAGS BEHIND. THIS
WILL KEEP PRECIP CHANCES THROUGHOUT THE SHORT TERM...ALTHOUGH MUCH
LIGHTER QPF EXPECTED WEDNESDAY...HIGHEST NEAR THE COAST.
FORECAST PROFILES SUGGEST A WEAK WEDGE SCENARIO (RARE FOR THIS EARLY
IN THE SEASON) DEVELOPING WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES
DOWN THE COAST WHILE SW FLOW REMAINS ABOVE 900MB. THIS SUGGESTS SOME
LIGHT RAIN OR EVEN DRIZZLE POTENTIALLY PERSISTING THROUGH THE END OF
THE PERIOD. VERY DRY AIR ABOVE THE WEDGE...PLUS THIS BEING OUT OF
SEASON...MEANS THAT ONLY SCHC POP WILL BE CONTINUED THROUGH THE END
OF THE SHORT TERM BUT CLOUD COVER SHOULD BE PRETTY
SIGNIFICANT...ESPECIALLY NEAR THE COAST.
HIGH TEMPS TUESDAY WILL BE RIGHT AROUND CLIMO...LOW 80S...AS STRONG
WAA IS COUNTERACTED BY CLOUD COVER AND SHOWERS...WHILE NIGHTTIME
MINS WILL BE HELD WELL ABOVE NORMAL...ONLY FALLING TO THE UPPER
60S/LOW 70S. WEDNESDAY WILL BE COOLER BEHIND THE FRONT...AROUND 80
FOR HIGHS AND NEAR 60 FOR LOWS AWAY FROM THE IMMEDIATE COAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...FRONT HOVERING JUST OFFSHORE MAY ALLOW FOR
CONTINUED SHOWERS NEAR THE COAST ON THURSDAY. FORECAST PROFILES DRY
OUT CONSIDERABLY HOWEVER...AND WILL DROP INHERITED CHC TO JUST SCHC
ON THE COAST...SILENT INLAND. BEST CHANCE WILL BE DURING THE EARLY
PART OF THE DAY BEFORE HIGH PRESSURE MORE FIRMLY RIDGES DOWN THE
COAST FORCING THE FRONT FURTHER OFFSHORE. OTHERWISE...THE EXTENDED
FEATURES DRY AND SEASONABLE WEATHER AS HIGH PRESSURE DOMINATES AT
THE SURFACE AND A LARGE UPPER TROUGH PERSISTS OVER THE EASTERN HALF
OF THE COUNTRY. ONLY FEATURE OF INTEREST IS A COLD FRONT WHICH WILL
TRY TO CROSS INTO THE AREA ON SATURDAY. WITH UPPER TROUGH RELOADING
ACROSS THE GREAT LAKES...MID LEVEL WINDS WILL REMAIN OUT OF THE WSW
WHICH WILL INHIBIT THIS FRONT FROM MAKING ANY NOTICEABLE IMPACT TO
THIS AREA...AND ANY COOLER AIR AND/OR PRECIP WILL BE DISPLACED NORTH
OF THE CWA.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...PERIODS OF MVFR/IFR OVERNIGHT AND INTO THE EARLY MORNING
HOURS WITH VCSH/SCATTERED SHRA AND POTENTIAL BR/LOW CIGS INLAND.
FOR SEVERAL HRS AFTER DAYBREAK...EXPECT VFR/MVFR WITH BRIEF
PERIODS OF IFR DUE TO SHRA/BR. FOR THE AFTERNOON/EVENING VFR WITH
BRIEF PERIODS OF MVFR/IFR FROM CONVECTION.
SHRA AND VCSH WILL CONTINUE THROUGH THE OVERNIGHT HOURS THROUGH
MID-MORNING. LOOKING AT NE-E LIGHT WINDS OVERNIGHT WITH THE BEST
CHANCE FOR LOW CEILINGS/FOG ACROSS THE INLAND SITES BEFORE
SUNRISE. AFTER DAYBREAK...LINGERING MVFR/IFR FOG WILL DISSIPATE
AND CIGS WILL LIFT GIVING WAY TO VFR. LOW TO MID SCT/BKN CLOUDS
WILL CONTINUE THROUGHOUT THE DAY WITH A CHANCE FOR MVFR FROM
SHRA/TSRA ACROSS THE AREA. EAST-SOUTHEAST WINDS WILL INCREASE TO
AOB 10 KTS BY THE AFTERNOON HOURS...BECOMING SOUTHERLY ALONG THE
COAST WITH GUSTS 15 TO 20 KTS. INTO THE EVENING HOURS...SHRA/TSRA
WILL GRADUALLY QUIET DOWN...EXCEPT FOR CONVECTIVE ACTIVITY OFF THE
ATL WATERS THAT COULD MOVE ONSHORE BY MIDNIGHT DUE TO A DEEPER
ONSHORE FLOW MATERIALIZING. SOUTHERLY WINDS TO INCREASE TO
SUSTAINED 10 KT BY MIDNIGHT...ESPECIALLY AT THE COASTAL TERMS.
THE EXTENDED OUTLOOK...SHRA/TSRA ON TUESDAY WITH MODERATE
CONFIDENCE FOR INTERMITTENT IFR CONDITIONS. CONVECTION WILL
CONTINUE INTO WEDNESDAY WITH IMPROVING CONDITIONS THURSDAY INTO
SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 640 AM MONDAY...SCA RAISED FOR ALL ILM WATERS FOR LATE
TONIGHT. SE-S WINDS 10 KT...WILL BECOME SOUTHERLY 10-15 KT BY THIS
AFTERNOON...AND FURTHER INCREASE TO 15 TO 20 KT TONIGHT. THIS IN
RESPONSE TO AN ORGANIZING SFC PRESSURE PATTERN...AND TIGHTENING SFC
PRESSURE GRADIENT DEVELOPING AHEAD OF THE APPROACHING SURFACE COLD
FRONT FROM THE WEST. SIGNIFICANT SEAS WILL INITIALLY COMMENCE AT 2
TO 4 FT...MAINLY COMPRISED OF A 10-12 SECOND SE SWELL. WITH
INCREASING WINDS LATER TODAY AND TONIGHT...LOCALLY PRODUCED WIND
DRIVEN WAVES AT 4 TO 7 SECOND AVERAGE PERIODS WILL BECOME MORE
DOMINANT. AT THIS POINT...SWAN ADVERTIZES SIG. SEAS REACHING 4 TO
6 FT ACROSS ALL WATERS JUST PRIOR TO DAYBREAK TUE...HENCE HAVE
RAISED THE SCA. WIND FIELDS JUST OFF THE DECK ARE PROGGED TO
REACH 40 KT AFTER MIDNIGHT TONIGHT. AS A RESULT...CONVECTION THAT
TRAVERSES THE ILM WATERS WILL TAP INTO THESE HIER WINDS AND
POTENTIALLY DROP THEM TO THE OCEAN SFC AS WIND GUSTS 35 KT OR
GREATER. FAVORABLE LOW LEVEL WIND SHEAR AND HODOGRAPH WILL AID
ISOLATED WATERSPOUT POSSIBILITIES...MAINLY BETWEEN MIDNIGHT AND UP
TO SEVERAL HOURS AFTER DAYBREAK TUE.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...STRONG SOUTHERLY WINDS AHEAD OF A POTENT COLD
FRONT WILL CREATE SMALL CRAFT ADVISORY CONDITIONS THROUGH MUCH OF
TUESDAY. WINDS OF 15-25 KTS WILL HELP BUILD SEAS TO 4-6 FT...HIGHEST
ACROSS THE NORTHERN WATERS. WAVES WILL BE FORMED BY A COMBINATION OF
A WEAK SE SWELL AND THE MORE DOMINANT 6 SEC SOUTHERLY WIND
WAVES...SO EXPECT RELATIVELY STEEP WAVE FACES THROUGH THE DAY.
ADDITIONALLY...STRONG THUNDERSTORMS ARE POSSIBLE AHEAD OF THE COLD
FRONT AS IT ADVANCES EASTWARD THROUGH THE EVENING. THESE STORMS
COULD PRODUCE MUCH STRONGER WIND GUSTS AND TORRENTIAL RAINFALL...AS
WELL AS LOCALLY ENHANCED WAVE HEIGHTS.
WINDS TURN WESTERLY EARLY WEDNESDAY WITH THE FRONT AND THEN BECOME
LIGHT AND VARIABLE AS THE BOUNDARY WAVERS OVER THE COASTAL WATERS.
BY LATE WEDNESDAY WINDS WILL BECOME NE...BUT REMAIN LESS THAN 10
KTS. SEAS FALL QUICKLY DURING THE DAY...FROM 3-5 FT EARLY TO 2-3 FT
LATE...THANKS TO THE EASING WIND SPEEDS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...HIGH PRESSURE RIDGES DOWN THE COAST THURSDAY
BEFORE DRIFTING OFFSHORE FRIDAY. NE WINDS OF AROUND 10 KTS PERSIST
MUCH OF THURSDAY BEFORE THE GRADIENT RELAXES...ALLOWING WINDS TO
BECOME LIGHT AND VARIABLE FRIDAY...BEFORE FINALLY TURNING TO THE SE
AT THE END OF THE PERIOD. WAVE GUIDANCE SHOWS SEVERAL DIFFERENT WAVE
GROUPS PRESENT IN THE SPECTRUM THROUGH THE EXTENDED...WITH NO GROUP
BECOMING DOMINANT. WITHOUT ANY MEANINGFUL SWELL OR PRESSURE
GRADIENT...SEAS WILL BE 1-3 FT THURSDAY...AND ONLY 1-2 FT ON FRIDAY.
&&
.TIDES/COASTAL FLOODING...
AS OF 350 AM MONDAY...BETWEEN 10 AM AND NOON TODAY...PROGGED MDL
WILMINGTON TIDE GAGE FORECASTS INDICATE A THREAT FOR GAGE READINGS
ABOVE THE 5.50 FT MLLW COASTAL FLOOD ADVISORY THRESHOLD BETWEEN 10
AM AND NOON TODAY. A PEAK OF 5.60 FT MLLW IS FORECAST AROUND 11
AM. THE PRONE LOCATIONS TO THIS TYPE OF SHALLOW FLOODING WILL
INCLUDE AREAS BORDERING ALONG THE CAPE FEAR RIVER SUCH AS WATER
STREET OF DOWNTOWN WILMINGTON... ROADWAYS LEADING TO AND FROM THE
USS NORTH CAROLINA BATTLESHIP... AND CANAL ROAD IN CAROLINA BEACH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 10 AM THIS MORNING TO NOON EDT
TODAY FOR NCZ107-108.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 5 AM EDT WEDNESDAY
FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DCH
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DCH/SGL
TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
425 PM EDT MON SEP 17 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM HUDSON BAY INTO NW MN AND SE SOUTH DAKOTAS. A SHORTWAVE OVER NE
SD WAS MOVING INTO THE BASE OF THE TROUGH. AT THE SFC...A COLD FRONT
EXTENDED FROM NRN LOWER MI INTO SE WI. A LARGE POST-FRONTAL RAINBAND
FROM CNTRL WI INTO CNTRL UPPER MI WAS SUPPORTED BY MODERATE TO
STRONG MID LEVEL FGEN AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF
THE 250-300 MB JET. NRLY WINDS AND 850 MB TEMPS FALLING TO AROUND 3C
SUPPORTED HEAVIER LAKE ENHANCED RAIN SHOWERS INTO N CNTRL UPPER MI.
WITH DRIER AIR UPSTREAM OVER NE MN THE WRN CWA...OVER THE FAR WRN
CWA VCNTY IWD...HAS DIMINISHED OR ENDED.
TONIGHT...MDLS SUGGEST THAT THE STRONGER FGEN DYNAMICS WILL LIFT OFF
TO THE NE LATE THIS AFTERNOON AND EVENING. HOWEVER...WITH CAA
DROPPING 850 MB TEMPS TO NEAR -3C OVER LAKE SUPERIOR TONIGHT LEADING
TO LK-H8 DELTA/T TO AROUND 20C AND THE 700-500 MB TROUGH MOVING
IN...LAKE EFFECT RAIN SHOWERS WILL DEVELOP AND INTENSIFY OVERNIGHT
FOR LOCATIONS FAVORED BY N WINDS. WITH THE LOW FREEZING LEVEL...SOME
GRAUPEL WILL BE POSSIBLE WITH THE HEAVIER SHOWERS. LAKE INDUCED
TROUGHING WITH MORE OF AN NNE FLOW OVER THE ERN LAKE SHOULD MINIMIZE
PCPN INTO THE FAR ERN CWA. UPSLOPE FLOW WILL LEAD TO THE HIGHEST
PCPN AMOUNTS OVER THE HIGHER TERRAIN OVER MARQUETTE AND BARAGA
COUNTIES.
TUESDAY...LAKE EFFECT PCPN WILL CONTINUE WITH THE 850 MB THERMAL
TROF STILL OVER THE AREA. AS WINDS BACK AND BECOME MORE ANTICYCLONIC
AND SOME LOW LEVEL DRYING MOVES IN FROM THE WEST...THE PCPN SHOULD
DIMINISH SHOULD DIMINISH FROM WEST TO EAST. SHOWERS DOWNWIND OF LAKE
SUPERIOR BECOMING MORE SCATTERED THROUGH THE DAY FROM WEST TO EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
TUE NGT...EXPECT LINGERING LK CLDS/-SHRA OVER MAINLY THE E HALF THRU
06Z TO END WITH APRCH OF PROGRESSIVE SHRTWV RDG/DNVA/ACCOMPANYING
DRY AIRMASS AND PASSAGE OF SFC HI PRES THAT CAUSES WSHFT TO THE SW
AND EXIT OF H85 THERMAL TROF. OTRW...LOOKS LIKE THERE SHOULD BE A
SEVERAL HOUR WINDOW OF OPTIMAL RADIATIONAL COOLING CONDITIONS ACROSS
MAINLY THE INTERIOR W AND CNTRL ACCOMPANYING THE PASSAGE OF THE RDG
AXIS/DRY AIR/LIGHT WINDS. OVER THE W...QUICKER WSHFT TO THE SW AFT
06Z WITH SHARPENING PRES GRADIENT AND SOME INCRSG HI/MID CLDS IN
ADVANCE OF NEXT SHRTWV DROPPING INTO MN WL END THE FAVORABLE COOLING
CONDITIONS WELL BEFORE SUNRISE...BUT NOT BEFORE TEMPS HAVE A CHANCE
TO CRASH BEFORE 06Z FM BLO NORMAL MAX READINGS ON TUE AFTN. OPTED TO
ISSUE FREEZE WATCH FOR THE INTERIOR W HALF...WHERE MOST GUIDANCE
SHOWS WDSPRD MIN TEMPS FALLING BLO 32.
WED...NEXT FAIRLY IMPRESSIVE SHRTWV DIVING SEWD THRU NW FLOW ALF
INTO MEAN TROF OVER ERN NAMERICA IS FCST TO MOVE NEAR UPR MI BY 00Z
THU. ALTHOUGH THE MSTR RETURN AHEAD OF THIS DISTURBANCE WL BE
ANEMIC DESPITE STRENGTHENING LLVL SLY FLOW...VIGOROUS DPVA/DEEP LYR
QVECTOR CNVGC SUPPORTS LIKELY POPS OVER THE N HALF OF THE CWA ON THE
CYC SIDE OF VORT MAX TRACK AND WHERE MOISTENING OFF LK SUP MIGHT
PLAY A ROLE.
WED NGT...DNVA/LARGER SCALE QVECTOR DVGC/HIER LVL DRYING IN THE WAKE
OF SHRTWV WL END LARGER SCALE PCPN CHCS W-E. BUT INCOMING AIRMASS WL
BE COLD ENUF WITH H85 TEMPS FCST AS LO AS 1-3C TO SUPPORT LK EFFECT
-SHRA IN AREAS IMPACTED BY FCST WNW FLOW...ESPECIALLY IF THE MORE
CYC FLOW SHOWN BY THE 12Z NAM/CNDN MODELS VERIFIES.
THU...THE ARRIVAL OF ANOTHER SHRTWV/SFC LO PRES TROF WL BRING MORE
SHRA CHCS DESPITE AN ABSENCE OF SGNFT DEEP LYR MOISTENING. QUESTIONS
ON TIMING/INTENSITY OF THIS DISTURBANCE INDICATE NO MORE THAN CHC
POPS ARE APPROPRIATE.
IN THE MEDIUM/EXTENDED RANGE...WITH MEAN TROF LINGERING OVER ERN
NAMERICA...EXPECT BLO NORMAL TEMPS TO PERSIST INTO EARLY NEXT WEEK.
MODELS SHOW A SERIES OF DISTURBANCES MOVING THRU THE MEAN TROF...SO
EXPECT SHOWERS TO PERSIST ESPECIALLY THRU SAT AND NEAR THE GREAT
LAKES. BEST CHC FOR A MORE WDSPRD RAINFALL APPEARS ON FRI WHEN
MODELS SHOW A PARTICULARLY STRONG DISTURBANCE IMPACTING THE AREA.
RECENT GFS RUNS SHOW THE MOST VIGOROUS SFC CYCLOGENESIS...AND WARM
LK WATERS MIGHT SUPPORT THAT SCENARIO. VARIOUS MODELS HINT THE UPR
TROF AXIS WL SHIFT A BIT FARTHER TO THE E NEXT SUN/MON WITH EPISODES
OF MORE ACYC FLOW/DRIER WX...BUT TIMING OF THESE FEATURES IS NOT
POSSIBLE ATTM. WL FOLLOW MODEL OF CONSENSUS LOWER POPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 132 PM EDT MON SEP 17 2012
A PERIOD OF STEADIER LIGHT RAIN OR DRIZZLE WILL AFFECT MAINLY CNTRL
UPPER MI THIS AFTERNOON. THE PCPN ALONG WITH UPSLOPE NRLY FLOW WILL
MAINTAIN LOWER END MVFR CIGS AT KSAW AND AT CMX. FARTHER WEST...SOME
DRIER AIR WILL MOVE INTO WRN UPPER MI THIS AFTERNOON WITH VFR
CONDITIONS AT IWD. ENOUGH COLD AIR WILL MOVE IN TONIGHT INTO TUE
MORNING FOR LAKE EFFECT PCPN WITH MAINLY MVFR CIGS FOR ALL OF THE TAF
SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EDT MON SEP 17 2012
20 TO 30 KT NORTH WINDS WILL CONTINUE IN THE SHORT TERM BUT DIMINISH
LATER TUESDAY AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST.
WINDS WILL GRADUALLY SHIFTING TO THE NW THEN W BY TUESDAY EVENING.
WINDS WILL BECOME LIGHT FOR AWHILE ON TUE NIGHT WITH THE PASSAGE OF
A HI PRES RIDGE ACROSS THE LAKE. BUT S WINDS WILL INCREASE QUICKLY
LATER AT NIGHT OVER THE W UNDER THE SHARPENING PRES GRADIENT BETWEEN
THE QUICKLY DEPARTING RIDGE AND AN INCOMING LO PRES TROUGH. AS THIS
DEEP TROF MOVES TO THE E...S WINDS ON WED MAY REACH GALE FORCE WHERE
THIS FLOW IS TYPICALLY ENHANCED OVER THE NCENTRAL AND E. ISSUED A
GALE WATCH WED AFTERNOON/EVENING IN THIS AREA TO ACCOUNT FOR THIS
STRONG FLOW AND FAIRLY UNSTABLE CONDITIONS OVER THE WARM LAKE WATER
THAT WILL ENHANCE MIXING. FOLLOWING THE PASSAGE OF THE TROF...LOOK
FOR A WIND SHIFT TO THE WNW WITH WINDS UP TO 25 TO 30 KTS INTO THU.
DEPENDING ON THE INTENSITY OF ANOTHER DISTURBANCE MOVING THRU THE
GREAT LAKES ON FRI/SAT...A STRONGER NNW FLOW IS POSSIBLE THEN. BUT
NO GALES ARE EXPECTED AT THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING
FOR MIZ002-004-005-009>013-084.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ267.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ266.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...JLB
MARINE...JLB/KC
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
118 PM CDT MON SEP 17 2012
.SHORT TERM...
ISSUED AT 334 AM CDT MON SEP 17 2012
(TODAY AND TONIGHT)
WHEN I WALKED IN THE DOOR AT 1000 PM LAST NIGHT I THOUGHT THE
FORECAST WAS GOING TO BE A BIT MORE CLEAR CUT THAN IT IS NOW. AREAS
OF DENSE FOG HAVE DEVELOPED OVERNIGHT...ESPECIALLY FROM ST LOUIS
NORTHWARD WHERE THERE ARE ONLY THIN HIGH CLOUDS AT THIS TIME.
MEANWHILE A PESKY AREA OF SHOWERS HAS ALSO DEVELOPED FROM SRN IL
ACROSS THE EASTERN OZARKS...APPARENTLY IN RESPONSE TO WEAK LOW
LEVEL WAA. VISIBILITIES HAVE IMPROVED SLIGHTLY IN THE ST LOUIS
AREA WITHIN THE LAST HOUR...AND THIS MAY BE DUE TO SOME THICKER
CLOUD COVER. I WILL HAVE TO MENTION SOME DENSE FOG THIS
MORNING...PROBABLY FROM I-70 NORTHWARD...BUT DONT HAVE ANY PLANS
FOR AN ADVISORY. THE PRECIPITATION TRENDS ARE A LITTLE MORE MURKY.
THE MODEL QPFS AND HRRR WANT TO KEEP A PERSIST THREAT OF SHOWERS
ACROSS THE SRN CWA THRU THE MORNING AND RAMPING UP INTO THE
AFTERNOON IN RESPONSE TO CONTINUED WAA AND LITTLE VORTS RIDING
ALONG THE NORTHERN FRINGE OF THE SHEAR AXIS THROUGH THE BOOTHEEL
REGION. MEANWHILE IT STILL LOOKS AS THOUGH THE AIR MASS ALONG AND
AHEAD OF THE ENCROACHING COLD FRONT WILL DESTABILIZE THIS
AFTERNOON AND THERE WILL BE SUFFICIENT FORCING FOR THE DEVELOPMENT
OF SCATTERED SHOWERS AND THUNDERSTORMS AND POSSIBLY A BROKEN LINE
FROM EASTERN MO INTO IL. THE POTENT NE-SW ORIENTED COLD FRONT
SHOULD BE BI-SECTING THE ST LOUIS AREA AT 00Z WITH GUSTY NORTHWEST
WINDS IN ITS WAKE AND GOOD CAA...WHILE A THREAT OF SHOWERS AND
THUNDERSTORMS WILL PERSIST ALONG AND AHEAD OF IT. THE FRONT SHOULD
CLEAR THE CWA BY MIDNIGHT ENDING THE PRECIPITATION THREAT AS
WELL...WITH CLOUDS CLEARING 3-4 HOURS BEHIND IT.
GLASS
&&
.LONG TERM...
ISSUED AT 334 AM CDT MON SEP 17 2012
(TUESDAY THROUGH SATURDAY)
WE WILL HAVE A TASTE OF FALL TUESDAY INTO WEDNESDAY MORNING WITH
WELL BELOW AVERAGE TEMPERATURES. GUSTY NORTHWEST WINDS WILL MAKE
IT FEEL EVEN COOLER ON TUESDAY. HIGH PRESSURE WILL SLIDE ACROSS
THE AREA ON TUESDAY NIGHT WITH THE CENTER OF THE HIGH NEAR THE
BOOTHEEL BY DAYBREAK WEDNESDAY. IT APPEARS THE COOLEST LOWS SHOULD
BE ACROSS THE SOUTHEAST HALF OF THE CWA AND ESPECIALLY THE EASTERN
OZARKS. SOME PATCHY FROST IS NOT OUT OF THE QUESTION IN SOME
SHELTERED SPOTS IN THE OZARKS WHERE MINS COULD FALL TO 36-38 DEGS.
LOW LEVEL WAA QUICKLY GETS UNDERWAY LATER ON WEDNESDAY MORNING AS
THE HIGH RETREATS AS SOUTHERLY FLOW KICKS IN. ANOTHER COLD FRONT
MAKES AN ATTEMPT TO MOVE THROUGH THE AREA ON THURSDAY BUT IT
WASHES OUT AS SURFACE PRESSURES BEGIN FALLING ACROSS THE PLAINS.
ANOTHER MORE FORMIDABLE COLD FRONT SHOULD MOVE THROUGH THE AREA ON
FRIDAY WITH A REINFORCING SHOT OF COOLER AIR ON ITS HEELS ABOUT
12H LATER.
GLASS
&&
.AVIATION...
ISSUED AT 117 PM CDT MON SEP 17 2012
FRONTAL BOUNDARY MAKING SLOW PROGRESS TO THE SOUTH ACROSS MO THIS
AFTERNOON. FRONT IS NEAR KUIN AND SHOULD MOVE THROUGH KCOU BY 19Z
AND METRO AREA BY 22Z. AS FOR PCPN CHANCES WITH BOUNDARY...
SCATTERED IN NATURE AND HARD TO PIN DOWN...SO JUST WENT WITH VCNTY
WORDING. ONLY MENTION VCTS IN KUIN AND KCOU AS THEY SHOULD SEE
SOME BREAKS IN THE CLOUD COVER...SO A BIT MORE INSTABILITY THERE.
OTHERWISE...FEEL THAT CLOUD COVER OVER METRO AREA TO REMAIN...SO
WILL BE HARD TO RECOVER...SO JUST HAVE VCNTY SHOWER MENTION THERE.
AS FOR WINDS...TO VEER TO THE WEST AS BOUNDARY MOVES
THROUGH...THEN A FEW HOURS LATER...VEER TO THE NORTH AND PICKUP TO
AROUND 10 KTS WITH GUSTS TO 20 KTS AT TIMES. SKIES TO GRADUALLY
CLEAR OUT AND WINDS DIMINISH OVERNIGHT. GRADIENT TIGHTENS ON
TUESDAY AND BRISK WINDS MIX DOWN...SO WILL SEE NORTHWEST WINDS
AROUND 15 KTS...GUSTING TO AROUND 25KTS...WITH JUST SOME SCATTERED
DIURNAL CU.
SPECIFICS FOR KSTL...FRONTAL BOUNDARY MAKING SLOW PROGRESS TO THE
SOUTH ACROSS MO THIS AFTERNOON. FRONT TO MOVE THROUGH METRO AREA
BY 22Z. AS FOR PCPN CHANCES WITH BOUNDARY... SCATTERED IN NATURE
AND HARD TO PIN DOWN...SO JUST WENT WITH VCNTY SHOWER WORDING...AS
CLOUD COVER TO LINGER...SO WILL BE HARD TO RECOVER. AS FOR
WINDS...TO VEER TO THE WEST AS BOUNDARY MOVES THROUGH...THEN A FEW
HOURS LATER...AROUND 02Z TUESDAY...VEER TO THE NORTH AND PICKUP TO
AROUND 10 KTS WITH GUSTS TO 20 KTS AT TIMES. SKIES TO GRADUALLY
CLEAR OUT AND WINDS DIMINISH BY 07Z TUESDAY. GRADIENT TIGHTENS ON
TUESDAY AND BRISK WINDS MIX DOWN...SO WILL SEE NORTHWEST WINDS
AROUND 15 KTS...GUSTING TO AROUND 25KTS...WITH JUST SOME SCATTERED
DIURNAL CU AFTER 16Z TUESDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
323 PM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL SUPPLY OUR REGION WITH
ONE MORE BEAUTIFUL DAY AS TEMPERATURES WILL SOAR WELL ABOVE NORMAL.
CONDITIONS WILL THEN DETERIORATE TONIGHT AS A COMPLEX STORM SYSTEM
WILL APPROACH FROM THE OHIO VALLEY. THE MOISTURE RICH SYSTEM WILL
SPREAD A SOAKING RAIN ACROSS OUR REGION LATE TONIGHT AND TUESDAY...
WITH SOME SITES PICKING UP OVER AN INCH OF RAIN. HIGH PRESSURE WILL
BRING US A CRISP FALL LIKE DAY FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
IDEAL LATE SUMMER WEATHER IS ON TAP FOR THE REST OF THE DAY AS
HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST REMAINS IN
CONTROL. SUBSIDENCE...COUPLED WITH A FAIRLY DRY AIRMASS...WILL
RESULT IN MOSTLY SUNNY SKIES...ALTHOUGH THERE WILL BE SOME
FAIR WEATHER CU...ESPECIALLY ACROSS THE GENESEE VALLEY AND FINGER
LAKES WHERE STEEPER LOW LEVEL LAPSE RATES ARE IN PLACE.
THE SOUTHERLY FLOW BETWEEN THE SURFACE HIGH AND THE MIDWEST COLD
FRONT WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 70S...AND
POSSIBLY 80 DEGREES IN SOME OF THE WARMER VALLEYS. THESE READINGS
WILL BE AT LEAST 10 DEG ABOVE NORMAL.
CLOUDS WILL THEN INCREASE AND THICKEN ACROSS OUR AREA TONIGHT AS A
VERY ENERGETIC...COMPLEX STORM SYSTEM APPROACHES FROM THE OHIO VALLEY.
RICH GULF MOISTURE POOLING OVER THE SOUTHERN STATES AHEAD OF THE
DEVELOPING STORM SYSTEM WILL BE WHISKED NORTHWARDS WITHIN H85-70
WINDS OF 70-80 KTS. THE CORE OF THESE WINDS WILL BE SOUTH OF OUR
REGION TONIGHT...BUT ARE FORECAST TO MOVE OVER EASTERN NEW YORK ON
TUESDAY. THESE EXTREMELY ANOMALOUS WINDS WILL BE AS MUCH AS 5
STANDARD DEVIATIONS FROM NORMAL IN THEIR STRENGTH...WHICH EQUATE TO
AN EVENT THAT HAS LESS THAN ONE HALF OF A PERCENT CHANCE OF
OCCURRENCE FOR THE PARTICULAR CALENDAR DAY.
THE COMPLEX STORM SYSTEM ITSELF WILL FEATURE A WAVY FRONTAL BOUNDARY
THAT WILL EVENTUALLY INCLUDE A DEEPENING SFC LOW. THE BURGEONING LOW
WILL RIDE ALONG THE FRONT AND LIFT FROM ABOUT WEST VIRGINIA LATE
TONIGHT TO OUR FINGER LAKES ON TUESDAY. A POTENT SHORTWAVE DIVING
INTO THE BASE OF A DIGGING H5 TROUGH OVER THE UPPER MISSISSIPPI
VALLEY WILL ENERGIZE THIS SFC WAVE...WHILE A H25 JET OF 140 KTS OVER
THE UPPER GREAT LAKES WILL PLACE OUR FORECAST AREA UNDER THE
INFLUENCE OF THE JET ENTRANCE REGION. THE COMBINATION OF THE LIFT
FROM THE RR QUAD OF THE H25 JET...THE STRONG LOW LEVEL JET AND
STEADY HGT FALLS WILL PRODUCE DEEP ASCENT FOR THE MOISTURE RICH
AIRMASS. PWAT VALUES WILL INCREASE TO MORE THAN 1.5" FOR MOST SITES.
BREAKING THIS DOWN INTO A FORECAST FOR TONIGHT...RAIN SHOULD
APPROACH THE NEW YORK PENNSYLVANIA LINE AROUND MIDNIGHT...THEN
SPREAD NORTH-NORTHEAST DURING THE REMAINING OVERNIGHT HOURS. THE
RAIN SHOULD REACH THE THOUSANDS ISLAND REGION BY ABOUT DAYBREAK.
BECAUSE OF THE STRONG SOUTHERLY FLOW ALOFT...TEMPS SHOULD REMAIN
WELL ABOVE SEASONAL VALUES TONIGHT WITH LOWS ONLY FORECAST TO DROP
TO WITHIN A COUPLE DEGREES OF 60. NEAR LAKE ERIE AND OVER PARTS OF
THE IAG FRONTIER...LOWS MAY BE CLOSER TO 65. AGAIN...THESE VALUES
WILL BE 10 OR MORE DEG F ABOVE NORMAL.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
DEEP MOISTURE WILL BE ON ITS WAY OUT AT THE START OF THE PERIOD...
AS THE SURFACE LOW WILL BE IN THE PROCESS OF LIFTING INTO EASTERN
CANADA AND THE COLD FRONT WILL BE PUSHING EAST OF THE AREA. STILL
COULD BE LOOKING AT THE BACK EDGE OF A HEAVY RAIN AREA ACROSS
EASTERN SECTIONS TUESDAY EVENING...BUT THIS SHOULD EXIT THE ENTIRE
AREA BEFORE MIDNIGHT. ONCE THE HEAVY RAIN AREA MOVES
OUT...INCREASING OVER-LAKE INSTABILITY IN A STRONG COLD AIR
ADVECTION REGIME WILL KEEP A CONTINUED THREAT FOR LAKE INDUCED
SHOWERS TO THE LEE OF THE LAKES...ESPECIALLY IN FAVORED
WEST-NORTHWEST FLOW AREAS. THE ARRIVAL OF A MUCH COOLER AIRMASS WILL
SEND OVERNIGHT LOWS INTO THE 40S...ALTHOUGH THEY COULD REMAIN IN THE
LOWER 50S ALONG THE MOST IMMEDIATE LAKESHORE AREAS.
LINGERING OVER-LAKE INSTABILITY WILL END WEDNESDAY MORNING AS
INCREASING SUBSIDENCE AND DRIER AIR WORK INTO THE REGION...AS A
SURFACE HIGH PRESSURE NOSES IN FROM THE SOUTHWEST. CHILLY DAY IN
STORE WITH MOST HIGHS IN THE UPPER 50S TO LOWER 60S.
MODELS CONCUR THAT HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH
THURSDAY WITH A FAIR WEATHER DAY. STRENGTHENING WARM AIR ADVECTION
WILL BRING HELP REBOUND TEMPERATURES BACK INTO THE UPPER 60S TO
LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE UPPER LEVEL PATTERN WILL BECOME HIGHLY AMPLIFIED THIS
PERIOD...AS A LONG WAVE TROUGH DEEPENS OVER THE EASTERN CONUS. A
BLOCKING PATTERN WILL HELP KEEP THE MAIN TROUGH AXIS FROM LIFTING
NORTHEAST...AS A SERIES OF SHORT WAVES DROP RAPIDLY SOUTHEAST OUT
OF CANADA INTO THE MAIN TROUGH OVER THE WESTERN GREAT LAKES
REGION.
LATEST MODELS SUGGESTING THAT A SHORTWAVE WILL PUSH ACROSS THE
NORTHERN GREAT LAKES LATE THURSDAY THEN INTO CANADA BY FRIDAY. THE
ASSOCIATED COLD FRONT WILL MAKE AN ATTEMPT TO APPROACH THE
REGION...BUT LOOKS TO GET HUNG UP IN AN UNFAVORABLE UPPER LEVEL FLOW
PATTERN. THIS BOUNDARY LOOKS TO DISSIPATE BEFORE IT REACHES THE
AREA. MOISTURE AND DYNAMICS REMAIN TO OUR NORTHWEST THEREFORE WE
SHOULD SEE LITTLE IF ANY PRECIPITATION ASSOCIATED WITH THIS FEATURE.
FRIDAY SHOULD BE THE WARMEST DAY OF THE WEEK WITH MOST HIGHS IN THE
MID TO UPPER 70S.
LATEST MEDIUM RANGE GUIDANCE AND ENSEMBLES CONTINUING TO INSIST
ON A RE-ENERGIZED COLD FRONT CROSSING THE AREA AT THE START OF THE
PERIOD. ALTHOUGH NOT A WASHOUT...THERE WILL BE A CHANCE OF
SCATTERED SHOWERS FRIDAY NIGHT AND SATURDAY WITH THE PASSAGE OF
THIS BOUNDARY. WEAK HIGH PRESSURE WILL BUILD ACROSS THE REGION IN
WAKE OF THE FRONT. HOWEVER...CYCLONIC FLOW PERSISTING ALOFT WILL
ALLOW FOR ADDITIONAL SHOWER DEVELOPMENT SATURDAY NIGHT AND SUNDAY.
COOLING 850 MB TEMPERATURES ALONG WITH WARM LAKE TEMPERATURES WILL
CREATE DELTA T/S NEAR 20C WHICH SHOULD SUPPORT RESPONSES OFF BOTH
LAKES. CYCLONIC FLOW DIMINISHES BY THE END OF THE PERIOD...AS
DRIER AIR BUILDS OVER THE LOWER LAKES WHICH SHOULD BRING IMPROVING
CONDITIONS FOR MONDAY. PATTERN ALOFT WOULD FAVOR GENERALLY BELOW
NORMAL TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
HIGH PRESSURE CENTERED ALONG THE MID ATLANTIC COAST WILL KEEP FAIR
VFR WEATHER IN PLACE THROUGH THE FIRST HALF OF TONIGHT.
LATER TONIGHT AND TUESDAY...MOISTURE TRACKING NORTH FROM THE
TENNESSEE VALLEY WILL INTERACT WITH A COLD FRONT MOVING EAST FROM THE
CENTRAL GREAT LAKES. AS THIS RAIN OVERSPREADS THE AREA...MVFR
CONDITIONS WILL DEVELOP...WITH IFR CONDITIONS LIKELY ACROSS THE
SOUTHERN TIER. AFTER THE COLD FRONT CROSSES THE WESTERN TAF SITES
DURING THE AFTERNOON...EXPECT IFR CONDITIONS TO BECOME MORE
WIDESPREAD.
SOME LOW LEVEL WIND SHEAR HAS BEEN ADDED TO THE TAF SITES LATE
TONIGHT AND TUESDAY MORNING. AS A POTENT LOW LEVEL JET PUSHES EAST
ACROSS WESTERN AND CENTRAL NEW YORK. THE BEST CHANCES FOR LLWS WILL
BE FROM KROC TO KART.
OUTLOOK...
TUESDAY NIGHT...MVFR/IFR IMPROVING TO MVFR/VFR WITH -RA TAPERING OFF
FROM WEST TO EAST.
WEDNESDAY...IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
SATURDAY...MAINLY VFR WITH CHANCE -SHRA.
&&
.MARINE...
WHILE HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST SHOULD
KEEP CONDITIONS BELOW SMALL CRAFT ADVISORY CRITERIA TODAY...WATERS
WILL BE QUITE CHOPPY ACROSS THE EASTERN PART OF LAKE ONTARIO THIS
MORNING AND THEN OVER PARTS OF LAKE ERIE DURING THE MIDDAY AND EARLY
AFTERNOON. IN THOSE AREAS...MODERATE SOUTHERLIES WILL PRODUCE WAVES
OF 2 TO 4 FEET SO THEY WILL HAVE TO BE CLOSELY WATCHED.
WINDS AND WAVES WILL BRIEFLY SUBSIDE ON BOTH LAKES THIS EVENING...
THEN A COMPLEX STORM SYSTEM WILL APPROACH THE LOWER GREAT LAKES
DURING THE OVERNIGHT. WINDS AHEAD OF THIS STORM SYSTEM WILL FRESHEN
OVER EASTERN LAKE ONTARIO LATER TONIGHT...POSSIBLY PRODUCING SCA
CONDITIONS BY DAYBREAK TUESDAY.
STRONGER WINDS ARE EXPECTED IN THE WAKE OF THE STORM SYSTEM TUESDAY
AFTERNOON AND NIGHT WITH FRESH WEST TO NORTHWEST BREEZES PRODUCING
SCA CONDITIONS ACROSS MUCH OF LAKE ONTARIO AND POSSIBLY FOR A SHORT
TIME...ON LAKE ERIE.
HIGH PRESSURE WILL MOVE IN ON WEDNESDAY TO PROMOTE WEAKER WINDS AND
LOWER WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM TUESDAY TO 11 AM EDT WEDNESDAY
FOR LEZ040-041.
SMALL CRAFT ADVISORY FROM 8 PM TUESDAY TO 2 PM EDT
WEDNESDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 11 AM EDT
WEDNESDAY FOR LOZ042.
SMALL CRAFT ADVISORY FROM 2 AM TO 7 AM EDT TUESDAY FOR
LOZ045.
SMALL CRAFT ADVISORY FROM 8 AM TUESDAY TO 8 AM EDT
WEDNESDAY FOR LOZ045.
&&
$$
SYNOPSIS...RSH
NEAR TERM...RSH/TJP
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...TJP
MARINE...RSH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
146 PM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL SUPPLY OUR REGION WITH
ONE MORE BEAUTIFUL DAY AS TEMPERATURES WILL SOAR WELL ABOVE NORMAL.
CONDITIONS WILL THEN DETERIORATE TONIGHT AS A COMPLEX STORM SYSTEM
WILL APPROACH FROM THE OHIO VALLEY. THE MOISTURE RICH SYSTEM WILL
SPREAD A SOAKING RAIN ACROSS OUR REGION LATE TONIGHT AND TUESDAY...
WITH SOME SITES PICKING UP OVER AN INCH OF RAIN. HIGH PRESSURE WILL
BRING US A CRISP FALL LIKE DAY FOR WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
IDEAL LATE SUMMER WEATHER IS ON TAP FOR THE REST OF THE DAY AS
HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST REMAINS IN
CONTROL. SUBSIDENCE...COUPLED WITH A FAIRLY DRY AIRMASS...WILL
RESULT IN MOSTLY SUNNY SKIES...ALTHOUGH THERE WILL BE SOME
FAIR WEATHER CU...ESPECIALLY ACROSS THE GENESEE VALLEY AND FINGER
LAKES WHERE STEEPER LOW LEVEL LAPSE RATES ARE IN PLACE.
THE SOUTHERLY FLOW BETWEEN THE SURFACE HIGH AND THE MIDWEST COLD
FRONT WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 70S...AND
POSSIBLY 80 DEGREES IN SOME OF THE WARMER VALLEYS. THESE READINGS
WILL BE AT LEAST 10 DEG ABOVE NORMAL.
CLOUDS WILL THEN INCREASE AND THICKEN ACROSS OUR AREA TONIGHT AS A
VERY ENERGETIC...COMPLEX STORM SYSTEM APPROACHES FROM THE OHIO VALLEY.
RICH GULF MOISTURE POOLING OVER THE SOUTHERN STATES AHEAD OF THE
DEVELOPING STORM SYSTEM WILL BE WHISKED NORTHWARDS WITHIN H85-70
WINDS OF 70-80 KTS. THE CORE OF THESE WINDS WILL BE SOUTH OF OUR
REGION TONIGHT...BUT ARE FORECAST TO MOVE OVER EASTERN NEW YORK ON
TUESDAY. THESE EXTREMELY ANOMALOUS WINDS WILL BE AS MUCH AS 5
STANDARD DEVIATIONS FROM NORMAL IN THEIR STRENGTH...WHICH EQUATE TO
AN EVENT THAT HAS LESS THAN ONE HALF OF A PERCENT CHANCE OF
OCCURRENCE FOR THE PARTICULAR CALENDAR DAY.
THE COMPLEX STORM SYSTEM ITSELF WILL FEATURE A WAVY FRONTAL BOUNDARY
THAT WILL EVENTUALLY INCLUDE A DEEPENING SFC LOW. THE BURGEONING LOW
WILL RIDE ALONG THE FRONT AND LIFT FROM ABOUT WEST VIRGINIA LATE
TONIGHT TO OUR FINGER LAKES ON TUESDAY. A POTENT SHORTWAVE DIVING
INTO THE BASE OF A DIGGING H5 TROUGH OVER THE UPPER MISSISSIPPI
VALLEY WILL ENERGIZE THIS SFC WAVE...WHILE A H25 JET OF 140 KTS OVER
THE UPPER GREAT LAKES WILL PLACE OUR FORECAST AREA UNDER THE
INFLUENCE OF THE JET ENTRANCE REGION. THE COMBINATION OF THE LIFT
FROM THE RR QUAD OF THE H25 JET...THE STRONG LOW LEVEL JET AND
STEADY HGT FALLS WILL PRODUCE DEEP ASCENT FOR THE MOISTURE RICH
AIRMASS. PWAT VALUES WILL INCREASE TO MORE THAN 1.5" FOR MOST SITES.
BREAKING THIS DOWN INTO A FORECAST FOR TONIGHT...RAIN SHOULD
APPROACH THE NEW YORK PENNSYLVANIA LINE AROUND MIDNIGHT...THEN
SPREAD NORTH-NORTHEAST DURING THE REMAINING OVERNIGHT HOURS. THE
RAIN SHOULD REACH THE THOUSANDS ISLAND REGION BY ABOUT DAYBREAK.
BECAUSE OF THE STRONG SOUTHERLY FLOW ALOFT...TEMPS SHOULD REMAIN
WELL ABOVE SEASONAL VALUES TONIGHT WITH LOWS ONLY FORECAST TO DROP
TO WITHIN A COUPLE DEGREES OF 60. NEAR LAKE ERIE AND OVER PARTS OF
THE IAG FRONTIER...LOWS MAY BE CLOSER TO 65. AGAIN...THESE VALUES
WILL BE 10 OR MORE DEG F ABOVE NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
VERY ACTIVE WEATHER WILL KICK OFF THIS PERIOD AS A SHARP UPPER LEVEL
TROUGH SLIDES EAST ACROSS THE GREAT LAKES REGION. AT THE SURFACE...
AN ASSOCIATED COMPLEX SURFACE LOW OVER OHIO AND SOUTHERN ONTARIO
TUESDAY MORNING WILL LIFT NORTHEAST INTO QUEBEC BY TUESDAY
EVENING...BEFORE RAPIDLY EJECTING NORTHWARD INTO LABRADOR BY
WEDNESDAY MORNING.
AS HAS BEEN PREVIOUSLY DETAILED IN THIS SPACE...THIS SYSTEM WILL BE
ACCOMPANIED BY A RICH SUPPLY OF GULF MOISTURE...WITH PRECIPITABLE
WATER VALUES RISING TO BETWEEN 1.5 AND 2 INCHES COURTESY OF THE DEEP
SOUTHWESTERLY SYNOPTIC-SCALE FLOW PRECEDING THE LOW. PLENTY OF
FORCING MECHANISMS WILL ALSO BE IN PLACE TO STRONGLY LIFT THIS
MOISTURE...INCLUDING STRONG HEIGHT FALLS AND WARM AIR ADVECTION
ALOFT...EXCELLENT LOW LEVEL CONVERGENCE IN THE VICINITY OF THE
SURFACE WAVE AND AT THE NOSE OF A DEVELOPING 70-80 KT LOW LEVEL
JET...AND STRONG UPPER LEVEL JET DYNAMICS SUPPLIED BY THE RIGHT REAR
QUAD OF A 120+ KT UPPER LEVEL JET STREAK. IT SHOULD GO WITHOUT
SAYING THAT ALL OF THIS MOISTURE AND LIFT WILL ADD UP TO A NEAR
CERTAINTY OF RAINFALL ON TUESDAY...SOME OF WHICH COULD BE HEAVY AT
TIMES. IN ADDITION...SOME WEAK ELEVATED INSTABILITY WILL ALSO BE
PRESENT ALOFT...AND THIS WILL ALSO ALLOW FOR THE POSSIBILITY OF SOME
ISOLATED EMBEDDED THUNDERSTORMS...ESPECIALLY GIVEN THE VERY STRONG
AND DYNAMIC NATURE OF THIS SYSTEM.
IN TERMS OF POTENTIAL RAINFALL AMOUNTS...THE NAM/GFS/GEM/ECMWF HAVE
ALL COME INTO BETTER AGREEMENT ON A SOMEWHAT MORE EASTERLY TRACK TO
THE SURFACE WAVE COMPARED TO 24 HOURS AGO...WITH THE MODEL CONSENSUS
THUS SUPERIMPOSING THE BEST OVERALL LIFT AND RICHEST MOISTURE...AND
CONSEQUENTLY THE GREATEST QPF...ACROSS OUR EASTERN FINGER LAKES AND
NORTH COUNTRY ZONES. IN THIS SPECIFIC REGION...A BLEND OF THE ABOVE
GUIDANCE PACKAGES SUGGEST THAT RAINFALL AMOUNTS OF 1 TO 1.5 INCHES
APPEAR POSSIBLE...WITH LOCALIZED AMOUNTS UP TO 2 INCHES NOT OUT OF
THE QUESTION. MEANWHILE FURTHER TO THE WEST...SOMEWHAT LESSER
RAINFALL AMOUNTS OF A HALF INCH TO AN INCH NOW APPEAR MORE LIKELY.
GIVEN THE VERY DRY ANTECEDENT CONDITIONS...THESE RAINFALL AMOUNTS
WILL BE UNLIKELY TO CAUSE ANY REAL FLOODING CONCERNS ACROSS LARGE
AREAS OR ALONG OUR LARGER CREEKS AND RIVERS...WITH ANY ISSUES MORE
THAN LIKELY REMAINING CONFINED TO LOCALIZED AREAS ALONG SMALLER
STREAMS AND LOW LYING/OTHER AREAS OF POOR DRAINAGE ACROSS OUR
EASTERN ZONES.
WITH ALL OF THE ABOVE IN MIND...HAVE ELECTED TO CONFINE ANY AREAS OF
POTENTIALLY HEAVY RAIN ON TUESDAY TO AREAS FROM THE GENESEE VALLEY
EASTWARD IN THE GRIDS AND WORDED FORECAST...AND WILL ALSO PULL BACK
SOMEWHAT ON THE HEAVY RAIN POTENTIAL IN THE HWO...AGAIN FOCUSING
THIS MORE ON OUR EASTERN ZONES WHERE THE HEAVIER RAINFALL IS MORE
LIKELY.
IN TERMS OF THE TIMING OF THE STEADIEST RAIN...THE ABOVE MODEL
CONSENSUS SUPPORTS A SOMEWHAT FASTER OVERALL TIMING COMPARED TO WHAT
WAS SEEN YESTERDAY...WITH THE STEADIEST AND MOST WIDESPREAD RAIN NOW
APPEARING AS IF IT WILL FALL BETWEEN MID TUESDAY MORNING AND MID
TUESDAY AFTERNOON. AFTER THAT TIME...THE STEADIEST RAINS WILL
QUICKLY TAPER OFF FROM WEST TO EAST BETWEEN LATE TUESDAY AFTERNOON
AND TUESDAY EVENING WITH THE PASSAGE OF THE TRAILING COLD FRONT...
WITH THE BACK EDGE OF THIS NOW APPEARING LIKELY TO EXIT OUR EASTERN
ZONES BETWEEN 03Z AND 06Z WEDNESDAY.
IN THE WAKE OF THE TRAILING COLD FRONT...A WEST-NORTHWESTERLY FLOW
OF MUCH COOLER AIR WILL FLOOD ACROSS THE REGION LATER TUESDAY AND
TUESDAY NIGHT...WITH 850 MB TEMPS PLUNGING TO BETWEEN 0C AND +3C BY
WEDNESDAY MORNING...THEN REMAINING AT THESE LEVELS RIGHT THROUGH
WEDNESDAY. WITH LAKE SURFACE TEMPS STILL RUNNING AROUND 21C...THIS
WILL BE PLENTY COLD ENOUGH TO SET OFF A LAKE RESPONSE...HOWEVER
MOISTURE WILL ONCE AGAIN BE A BIG LIMITING FACTOR THANKS TO
PLENTIFUL DRY AIR AND SUBSIDENCE ADVECTING IN BEHIND THE DEPARTING
LOW/COLD FRONT. WITH THE BULK OF ANY MOISTURE CONFINED TO 5-6 KFT OR
BELOW...WILL ONLY INDICATE SOME LINGERING LOWER-END CHANCE POPS
EAST-SOUTHEAST OF THE LAKES TUESDAY NIGHT...WITH ANY SCATTERED LAKE
EFFECT RAIN SHOWERS THEN FALLING APART ALTOGETHER ON WEDNESDAY WITH
DIURNAL INFLUENCES...AND AS HIGH PRESSURE BUILDS DIRECTLY OVERHEAD
ALONG WITH FURTHER DRYING AND INCREASING SUBSIDENCE. AFTER
THAT...DRY AND QUIET WEATHER IS EXPECTED TO CONTINUE THROUGH
WEDNESDAY NIGHT WITH THE AXIS OF THE AFOREMENTIONED SURFACE RIDGE
REMAINING PARKED DIRECTLY OVERHEAD.
WITH REGARD TO TEMPERATURES...FOLLOWING HIGHS IN THE MID 60S TO
LOWER 70S ON TUESDAY...EXPECT A SHARP COOLDOWN FOR THE REMAINDER
OF THE PERIOD GIVEN THE STRONG COLD AIR ADVECTION PATTERN BEHIND
THE DEPARTING LOW. EXPECT LOWS TO FALL BACK TO THE MID TO UPPER
40S TUESDAY NIGHT...WITH DAYTIME HIGHS ON WEDNESDAY THEN BARELY
REACHING 60 OR SO ACROSS THE LOWER ELEVATIONS...AND LIKELY NOT
MAKING IT OUT OF THE UPPER 50S ACROSS THE HIGHER TERRAIN. EVEN
COOLER READINGS IN THE LOWER TO MID 40S WILL THEN FOLLOW FOR
WEDNESDAY NIGHT...WITH UPPER 30S FOUND ACROSS INTERIOR PORTIONS OF
THE SOUTHERN TIER AND NORTH COUNTRY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE FIRST HALF OF THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A
LINGERING BROAD/FLAT TROUGH OVER EASTERN NORTH AMERICA RELOADING TO
OUR WEST...AS ANOTHER STRONG SHORTWAVE TROUGH PLUNGES SOUTHEASTWARD
ACROSS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. OUT AHEAD OF
THIS SHORTWAVE...THE PREVAILING SYNOPTIC-SCALE FLOW WILL AGAIN TURN
SOUTHWESTERLY...AND THIS WILL HELP TO TRANSPORT MUCH WARMER AIR BACK
INTO OUR REGION FOR A COUPLE OF DAYS. A BLEND OF THE 00Z GFS AND
ECMWF SUGGESTS 850 MB TEMPS RECOVERING TO BETWEEN +5C AND +8C
THURSDAY AND TO AROUND +11C/+12C FRIDAY...WHICH SHOULD BE ENOUGH TO
BOOST HIGH TEMPS BACK INTO THE 65-70 DEGREE RANGE ON THURSDAY...AND
AT LEAST THE LOWER TO MID 70S ON FRIDAY. THUS...WEDNESDAY`S SHARP
COOLDOWN WILL BE VERY BRIEF...WITH TEMPERATURES RECOVERING TO A BIT
ABOVE NORMAL LEVELS BY THE END OF THE WORK WEEK.
IN TERMS OF PRECIPITATION CHANCES...THE GFS AND ECMWF ARE NOW IN
BETTER AGREEMENT THAT THE VAST MAJORITY OF THE THURSDAY-FRIDAY TIME
FRAME SHOULD REMAIN DRY. BOTH MODELS WEAKEN AN INITIAL LEAD COLD
FRONT AS IT TRIES TO PRESS TOWARD OUR AREA ON THURSDAY...WITH THIS
FEATURE EVENTUALLY FALLING APART OVER SOUTHERN ONTARIO LATE THURSDAY
AND THURSDAY NIGHT. BOTH PACKAGES ALSO ARE NOW IN BETTER AGREEMENT
ON THE EVOLUTION OF A SUBSEQUENT SURFACE WAVE AND ASSOCIATED
STRONGER COLD FRONT...WITH THIS LATTER FEATURE ONLY APPROACHING
FAR WESTERN NEW YORK BY LATE FRIDAY AFTERNOON/FRIDAY EVENING. WITH
THE ABOVE IN MIND...HAVE KEPT PRECIP CHANCES FOR BOTH DAYS LARGELY
CONFINED TO SLIGHT CHANCE OR LESS...WITH ONLY SOME LOW CHANCE POPS
INDICATED ACROSS FAR WESTERN NEW YORK LATER FRIDAY AFTERNOON.
AFTER THAT...BOTH GUIDANCE PACKAGES DIG THE LARGE-SCALE UPPER TROUGH
DEEPER INTO THE CENTRAL AND EASTERN GREAT LAKES NEXT WEEKEND...WITH
THE AFOREMENTIONED SECOND COLD FRONT SLOWLY PUSHING ACROSS THE AREA
BETWEEN FRIDAY NIGHT AND SATURDAY...FOLLOWED BY A SECONDARY AND
WEAKER AREA OF LOW PRESSURE PASSING BY TO OUR NORTH ON SUNDAY. AT
THIS DISTANT JUNCTURE...THIS EVOLUTION IN THE PATTERN WILL SUPPORT
SOME BROADBRUSH LOWER-END SHOWER CHANCES BOTH DAYS...ALONG WITH A
TREND TOWARD PROGRESSIVELY COOLER TEMPERATURES AS THE COLD POOL
ASSOCIATED WITH THE UPPER LOW OVERSPREADS OUR REGION.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
HIGH PRESSURE CENTERED ALONG THE MID ATLANTIC COAST WILL KEEP FAIR
VFR WEATHER IN PLACE THROUGH THE FIRST HALF OF TONIGHT.
LATER TONIGHT AND TUESDAY...MOISTURE TRACKING NORTH FROM THE
TENNESSEE VALLEY WILL INTERACT WITH A COLD FRONT MOVING EAST FROM THE
CENTRAL GREAT LAKES. AS THIS RAIN OVERSPREADS THE AREA...MVFR
CONDITIONS WILL DEVELOP...WITH IFR CONDITIONS LIKELY ACROSS THE
SOUTHERN TIER. AFTER THE COLD FRONT CROSSES THE WESTERN TAF SITES
DURING THE AFTERNOON...EXPECT IFR CONDITIONS TO BECOME MORE
WIDESPREAD.
SOME LOW LEVEL WIND SHEAR HAS BEEN ADDED TO THE TAF SITES LATE
TONIGHT AND TUESDAY MORNING. AS A POTENT LOW LEVEL JET PUSHES EAST
ACROSS WESTERN AND CENTRAL NEW YORK. THE BEST CHANCES FOR LLWS WILL
BE FROM KROC TO KART.
OUTLOOK...
TUESDAY NIGHT...MVFR/IFR IMPROVING TO MVFR/VFR WITH -RA TAPERING OFF
FROM WEST TO EAST.
WEDNESDAY...IMPROVING TO VFR.
THURSDAY AND FRIDAY...MAINLY VFR.
SATURDAY...MAINLY VFR WITH CHANCE -SHRA.
&&
.MARINE...
WHILE HIGH PRESSURE ANCHORED OFF THE MIDDLE ATLANTIC COAST SHOULD
KEEP CONDITIONS BELOW SMALL CRAFT ADVISORY CRITERIA TODAY...WATERS
WILL BE QUITE CHOPPY ACROSS THE EASTERN PART OF LAKE ONTARIO THIS
MORNING AND THEN OVER PARTS OF LAKE ERIE DURING THE MIDDAY AND EARLY
AFTERNOON. IN THOSE AREAS...MODERATE SOUTHERLIES WILL PRODUCE WAVES
OF 2 TO 4 FEET SO THEY WILL HAVE TO BE CLOSELY WATCHED.
WINDS AND WAVES WILL BRIEFLY SUBSIDE ON BOTH LAKES THIS EVENING...
THEN A COMPLEX STORM SYSTEM WILL APPROACH THE LOWER GREAT LAKES
DURING THE OVERNIGHT. WINDS AHEAD OF THIS STORM SYSTEM WILL FRESHEN
OVER EASTERN LAKE ONTARIO LATER TONIGHT...POSSIBLY PRODUCING SCA
CONDITIONS BY DAYBREAK TUESDAY.
STRONGER WINDS ARE EXPECTED IN THE WAKE OF THE STORM SYSTEM TUESDAY
AFTERNOON AND NIGHT WITH FRESH WEST TO NORTHWEST BREEZES PRODUCING
SCA CONDITIONS ACROSS MUCH OF LAKE ONTARIO AND POSSIBLY FOR A SHORT
TIME...ON LAKE ERIE.
HIGH PRESSURE WILL MOVE IN ON WEDNESDAY TO PROMOTE WEAKER WINDS AND
LOWER WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RSH
NEAR TERM...RSH/TJP
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...TJP
MARINE...RSH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
403 PM EDT MON SEP 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. A STRONG COLD FRONT WILL
APPROACH THE AREA TUESDAY AND MOVE OFFSHORE WEDNESDAY AFTERNOON. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT THURSDAY AND FRIDAY. AN
EVEN STRONGER COLD FRONT WILL MOVE ACROSS THE AREA SATURDAY INTO
SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 345 PM MONDAY...SCATTERED SHOWERS CONTINUE OVER MOST OF
EASTERN NORTH CAROLINA AWAY FROM THE SOUTHERN COAST IN ASSOCIATION
WITH WEAK BOUNDARY. ALTHOUGH NO LIGHTNING HAS BEEN OBSERVED SO FAR
TODAY...THERE IS SUFFICIENT INSTABILITY FOR A FEW EMBEDDED TSTMS
AND WILL LEAVE IN FORECAST. RAP AND NAM12 INDICATE A BIT OF A
BREAK OF THE PRECIP LATER TONIGHT...BUT NOT CONFIDENT IN THAT
GIVEN THAT COVERAGE HAS ALREADY BEEN HIGHER THAN PREVIOUS FORECAST
BY THOSE MODELS. MINIMUM TEMPERATURES TONIGHT SHOULD BE IN THE
UPPER 60S TO LOWER 70S UNDER MOSTLY CLOUDY SKIES.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
AS OF 345 PM MONDAY...TUESDAY LOOKS TO BE A WET DAY AHEAD OF
APPROACHING STRONG COLD FRONT. PRECIPITABLE WATER VALUES SURGE TO
NEARLY 2.5 INCHES BY 18Z AND SHOWERS AND TSTMS BECOME WIDESPREAD.
HAVE HIGH LIKELY TO CATEGORICAL POPS OVER THE WESTERN AREAS BY
LATE MORNING...SPREADING TO THE COAST DURING THE AFTERNOON HOURS.
THE ENTIRE CWA REMAINS IN A SLIGHT RISK OF SEVERE TSTMS FOR
TUESDAY AS WELL. WHILE THERE WILL BE SOME MODERATE INSTABILITY
OVER THE SOUTHERN COUNTIES...ESPECIALLY IF WE GET SOME
INSOLATION...THE BEST SHEAR VALUES WILL MAINLY BE TO OUR NORTH
OVER VIRGINIA AND AREAS FURTHER NORTH. THINK THE BEST CHANCE FOR
SEVERE WOULD BE IN OUR NORTHERN COUNTIES CLOSER TO THE MID/UPPER
LEVEL JET MAXIMUM. WENT A COUPLE OF DEGREES BELOW NUMERICAL
GUIDANCE TEMPERATURES GIVEN EXPECTED CLOUD COVER AND ONGOING
PRECIPITATION EARLY IN THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 330 PM MONDAY...LITTLE CHANGE IN FORECAST REASONING FOR THE
AFTERNOON PACKAGE. A COLD FRONT WILL APPROACH FROM THE W TUE NIGHT
AND SLOWLY MOVE OFFSHORE WED AS UPR TRF DEVELOPS TO THE W. VERY DEEP
MOISTURE AHEAD OF THE FRONT WITH PRECIP WTR VALUES AOA 2 INCHES
THROUGH TUE NIGHT OVER THE AREA. THIS COMBINED WITH DECENT FORCING
WILL LEAD TO GOOD CVRG OF SHRA AND A FEW TSRA. THREAT OF SOME
STRONG/SVR STORMS WITH GUSTY WINDS CONTINUES TUE NIGHT WITH DESCENT
FORCING DESPITE LOSS OF SFC BASED INSTABILITY. VERY WARM TEMPS ALOFT
SHLD LIMIT HAIL THREAT.
WITH THE UPR TRF EXPECTED TO CONT TO THE W THRU THE END OF THE WEEK
THE FRONT WILL ONLY SLOWLY CROSS LATE TUE NIGHT AND WED AND WL
LIKELY LINGER JUST OFF THE CST INTO THU. THIS WILL KEEP CHC OF SHRA
GOING ESPCLY CST WED AND WED NIGHT WITH SLIGHT CHC CST THU. SHLD BE
MAINLY DRY FRI AND SAT AS HIGH PRES CROSSES THEN CONT A SLIGHT POP
SUNDAY ASSOC WITH NEXT FRONT. VERY LITTLE QPF EXPECTED WITH THIS
FRONT WITH LIMITED GULF MOISTURE FEED.
HIGHS MAINLY 70S WED AND THU BEHIND FRONT AS EXPECT PLENTY OF
CLOUDS. WITH MORE SUN EXPECT LOWER 80S AGAIN MOST AREAS FRI INTO THE
WEEKEND. BELOW NORMAL TEMPS AND DRY CONDITIONS EXPECTED EARLY NEXT
WEEK WITH COOL HIGH PRES BUILDING IN BEHIND THE COLD FRONT.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 4 PM MONDAY...EXPECT CEILINGS TO GRADUALLY LOWER THROUGH THE
EVENING AND REACH MVFR STATUS DURING THE EARLY MORNING HOURS.
SHOWERS AND TSTMS BECOME WIDESPREAD BY MID-MORNING TUESDAY
ACCOMPANIED BY GUSTY SOUTH WINDS. WHILE CEILINGS WILL GENERALLY BE
VFR EXPECT NUMEROUS REDUCTIONS TO MVFR AND PERHAPS BRIEFLY IFR
IN HEAVIER SHOWERS TUESDAY AFTERNOON AND EVENING.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 330 PM MON...NUMEROUS SHRA AND A FEW TSRA WILL CONTINUE
TUE NIGHT WITH PDS OF REDUCED CIGS AND VSBYS LIKELY. PRECIP
WILL GRADUALLY END FROM W TO E WED AND WED NIGHT HOWEVER WITH POST
FRONTAL INVERSION AND PLENTY OF LOW LVL MOISTURE LOW CLOUDS IN
MVFR TO OCNL IFR RANGE WILL PERSIST. LOW LVLS SHLD DRY THU WITH
VFR BECOMING DOMINATE AND THAT SHLD CONT FRI AND SAT.
&&
.MARINE...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 4 PM MONDAY...SE/SSE WINDS CONTINUE IN THE 10 TO 15 KNOT
RANGE LATE THIS AFTERNOON WITH 3 TO 4 FOOT SEAS ACCOMPANIED BY A
10 TO 12 SECOND SWELL COMPONENT. AS THE STRONG COLD FRONT
APPROACHES THIS EVENING...SOUTHERLY WINDS SHOULD START TO RAMP UP
AFTER MIDNIGHT AND BE GUSTY AT 20 TO 25 KNOTS ON TUESDAY. HAVE
ADDED THE ALBEMARLE AND PAMLICO SOUNDS TO THE SMALL CRAFT ADVISORY
FROM TUESDAY MORNING THROUGH THE DAY TUESDAY INTO EARLY WEDNESDAY.
SEAS SHOULD BUILD TO AS HIGH AS 7 TO 8 FEET...ESPECIALLY OVER THE
OUTER WATERS BY LATE TONIGHT AND THROUGH TUESDAY. THE ROUGH SEAS
AND HIGHER THAN NORMAL TIDES WILL LEAD TO A MODERATE RIP CURRENT
THREAT ON TUESDAY.
LONG TERM /TUESDAY EVENING THROUGH FRIDAY/...
AS OF 330 PM MON...SCA WILL BE ONGOING TUE EVE WITH SRLY WINDS OF 20
TO 25 KTS. 12Z WAVEWATCH A LITTLE HIGHER WITH SEAS...NOW PEAKING
AROUND 6 TO 8 FEET OUTER WTRS TUE NIGHT. THE GUSTY S/SW WINDS WILL
DIMINISH TOWARD WED MORN AS FRONT REACHES CST WITH SEAS EXPECTED TO
DROP BELOW SCA CRITERIA ALL WATERS AROUND MID DAY WED. DECENT NRLY
FLOW WILL DEVELOP WED AFTN AS FRONT DRIFTS OFFSHORE...FOR NOW HAVE
WINDS AOB 20 KTS BEHIND FRONT WITH SEAS NO HIGHER THAN 5 FEET. N/NE
WINDS WILL CONT THU THROUGH FRI AT MAINLY 10 TO 15 KTS AS HIGH PRES
BUILDS TO THE CST AND FRONT DRIFTS OFFSHORE. SEAS OF 2 TO 4 FEET THU
WILL SUBSIDE A BIT FRI AS WINDS BECOME LIGHT WITH HIGH NEAR THE CST.
WINDS COME AROUND TO S/SWLY SAT AS HIGH PRES WEAKENS AND A COLD
FRONT QUICKLY APPROACHES FROM THE NW. AT THIS TIME MODELS KEEP WINDS
AOB 15 KT WHILE WAVEWATCH BUILDS SEAS TO 3-5 FT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ095-
103-104.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 8 AM EDT WEDNESDAY
FOR AMZ130-135-150.
SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 2 PM EDT WEDNESDAY
FOR AMZ152-154.
SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 11 AM EDT WEDNESDAY
FOR AMZ156-158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...SK/RF
AVIATION...CTC/SK/RF
MARINE...CTC/SK/RF
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
319 PM CDT MON SEP 17 2012
DISCUSSION...CONTINUING TO SEE DEEPENING LOWER PRESSURE ALONG THE
GULF COAST THIS AFTERNOON. CURRENTLY...THIS FEATURE IS VERY CLOSE
TO THE COASTLINE OF LOUISIANA. MEANWHILE...UPPER LEVEL TROUGH OVER
EASTERN TX WITH THE ASSOCIATED AXIS EXTENDING NORTH NORTHEASTWARD.
STRONG PVA WILL CONTINUE TO RESIDE ALONG THE NE TRACK OF THE SFC
LOW AND THIS WILL RESULT IN FURTHER STRENGTHENING THROUGH TONIGHT.
IN ADVANCE OF THE APPROACHING SFC LOW...AN AREA OF INCREASING
INSTABILITY IS MOVING NORTHWARD FROM MS AND AL. THIS WILL CONTINUE
TO ADD TO THE FLOOD THREAT WITH THE POTENTIAL OF FLASH FLOODING.
LATEST HRRR RUN SHOWS SCATTERED TO BROKEN HEAVIER SHOWERS AND TSTMS
OCCURRING ACROSS OUR SOUTHERN AREAS BETWEEN NOW AND THIS EVENING.
THEN...LATER TONIGHT...ANOTHER ROUND OF WIDESPREAD RAINFALL WILL
MOVE ACROSS THE AREA. THIS ONSLAUGHT OF WIDESPREAD RAINFALL WILL BE
IN CONJUNCTION WITH THE STRENGTHENING SFC LOW THAT WILL BE MOVING
CLOSER. IN FACT...THE SFC LOW SHOULD REACH MIDDLE TN AROUND OR
SHORTLY AFTER MIDNIGHT TONIGHT. THE HEAVIEST RAINFALL SHOULD BEGIN
TO EXIT OUR PLATEAU AREA SHORTLY AFTER MIDNIGHT.
HOWEVER...RAINFALL...THOUGH LIGHTER...SHOULD CONTINUE INTO TUESDAY
MORNING.
ADDITIONAL PREDICTED RAINFALL AMOUNTS FROM 4 PM THROUGH TONIGHT WILL
INCLUDE 3 TO 5 INCHES ALONG THE CUMBERLAND PLATEAU...2 TO 3 INCHES
FOR THE CENTRAL THIRD OF THE MID STATE...AND AROUND 1 INCH ACROSS
THE WEST. LOCALLY HIGHER AMOUNTS WILL ALSO BE POSSIBLE. THE
PRECIPITATION SHOULD TAPER OFF TO LIGHT RAIN AND/OR DRIZZLE AFTER
SUNRISE ON TUESDAY.
OTHERWISE...COOLER AND DRIER AIR WILL BEGIN MOVING IN BY TUESDAY
AFTERNOON. CLOUDS SHOULD BEGIN TO DECREASE BY AFTERNOON ACROSS
WESTERN AREAS. THE COOL SPELL WILL CONTINUE THROUGH THURSDAY. AS THE
SFC HIGH REACHES MIDDLE TN ON WEDNESDAY AND THURSDAY
MORNING...OVERNIGHT LOW TEMPERATURES WILL FALL INTO THE 40S.
IN THE EXT FCST...A BRIEF WARMUP WILL OCCUR ON FRIDAY IN ADVANCE OF
THE NEXT FRONTAL SYSTEM. AFTER A 20-30 PERCENT CHANCE OF SHOWERS FOR
FRI NT AND SATURDAY...IT WILL AGAIN TURN COOL WITH LOWS IN THE 40S
AND HIGHS IN THE LOWER 70S FOR SUNDAY AND MONDAY.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 63 70 46 71 / 90 50 10 05
CLARKSVILLE 61 69 43 72 / 80 50 10 05
CROSSVILLE 62 69 46 67 / 100 80 10 10
COLUMBIA 64 71 46 72 / 90 50 10 05
LAWRENCEBURG 63 71 46 72 / 90 60 10 05
WAVERLY 62 70 43 72 / 80 50 10 05
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH TUESDAY MORNING FOR TNZ008>011-027>034-
058>066-075-077>080-093>095.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1212 PM CDT MON SEP 17 2012
.UPDATE...MAIN CONCERN THIS UPDATE WERE WX AND POP GRIDS. RADAR
MOSAIC SHOWS A SWATH OF PRECIP STRETCHING FROM NORTHERN WISCONSIN
TO SOUTHEAST MN AND CENTRAL IA. THIS FEATURE ANTICIPATED TO
PROVIDE THE BULK OF THE PRECIPITATION TODAY...AND IS ASSOCIATED
WITH LOW LEVEL FRONOTOGENESIS. SURFACE FRONT IS SEEN ALONG OUR FAR
NW PORTION OF THE FORECAST AREA AT THE MOMENT...AND IT SHOULD EXIT
THE FAR SE BETWEEN 21 AND 00 UTC.
WX AND POPS WERE PUSHED BACK SOMEWHAT THIS AFTERNOON. HRRR AND
NAM12 MODEL REFLECTIVITY FIELDS HAVE BEEN TRENDING WELL WITH RADAR
MEASUREMENTS. GIVEN THIS AND LATEST RADAR TRENDS...EXPECT AREA OF
SHOWERS AND ISOLATED THUNDERSTORMS TO ENTER SOUTH CENTRAL WI
BETWEEN 2 AND 4 PM CDT...AND SOUTHEAST WI BETWEEN 4 PM AND 6 PM.
KEPT AN AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ALONG
AND AHEAD OF THE FRONT AS WELL EARLIER THIS AFTERNOON.
THE AREA OF RAIN SHOWERS SHOULD CORRESPOND WELL WITH WHERE THE
BETTER LOW LEVEL FRONTOGENETIC RESPONSE IS SEEN. THIS WILL BE IN
THE LOWER LEVELS OF THE ATMOSPHERE AT 18 AND 00 UTC...LOOKING AT
1000-850 AND 850-700 HPA LAYERS.
&&
.AVIATION/18Z TAFS/...COLD FRONT WILL PUSH SOUTHEAST ACROSS TAF
SITES THROUGH 22Z THIS AFTERNOON...WITH QUICK WIND SHIFT TO THE
NORTHWEST ACCOMPANYING THE FRONT. NORTHWEST WINDS WILL BE GUSTY
BEHIND THE FRONT...GUSTING IN THE 20 TO 25 KNOT RANGE UNTIL EARLY
THIS EVENING.
A BAND OF SHOWERS IS EXPECTED TO SHIFT THROUGH THE AREA BEHIND
THE FRONT LATER THIS AFTERNOON...LASTING INTO EARLY THIS EVENING
ACROSS THE EASTERN TAF SITES. ISOLATED THUNDERSTORMS MAY FORM
ALONG THE COLD FRONT AS WELL...BUT LEFT MENTION OUT OF TAFS FOR
NOW. MVFR CEILINGS ARE POSSIBLE WITH THE BAND OF SHOWERS...THOUGH
SHOULD ALTERNATE BETWEEN MVFR AND VFR CATEGORY.
NORTHWEST WINDS WILL REMAIN MODERATE TONIGHT INTO TUESDAY...WITH
GUSTS UP TO 20 KNOTS POSSIBLE TUESDAY AFTERNOON. VFR CEILINGS
SHOULD GRADUALLY MIX OUT AS THE NIGHT GOES ON...WITH DRIER AIR
WORKING INTO THE REGION.
UNSTABLE CONDITIONS TUESDAY AFTERNOON SHOULD ALLOW FOR SCATTERED
TO BROKEN CUMULUS CLOUDS TO DEVELOP...WITH A FEW SHOWERS POSSIBLE.
LEFT SHOWER MENTION OUT OF TAFS FOR NOW DUE TO UNCERTAINTY WITH
AREAL COVERAGE.
&&
.MARINE...SMALL CRAFT ADVISORY GOES INTO EFFECT FOR THE NEARSHORE
WATERS AT 21Z THIS AFTERNOON...LASTING THROUGH 00Z WEDNESDAY.
TIGHT PRESSURE GRADIENT DEVELOPS BEHIND THE COLD FRONT LATE THIS
AFTERNOON AND TONIGHT...SLOWLY WEAKENING ON TUESDAY. THIS SHOULD
ALLOW FOR GUSTY NORTHWEST WINDS TO 25 KNOTS DURING THIS TIME.
SUBSEQUENT HIGH WAVES OF 3 TO 6 FEET SHOULD DEVELOP TOWARD THE
OPEN WATERS LATER TONIGHT INTO TUESDAY...BEFORE SUBSIDING LATE ON
TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 334 AM CDT MON SEP 17 2012/
SHORT TERM...
TODAY AND TONIGHT...CONFIDENCE - MEDIUM.
MID-LEVEL CLOUDS INCREASING AHEAD OF APPROACHING SFC COLD
FRONT...CURRENTLY EXTENDING FROM NORTHEAST WI TO NEAR KLSE. CLOUDS
AN INDICATOR OF INCREASING LOW-MID LEVEL RH IN OUR AREA AS GOES
SOUNDER MEASURED PRECIPITABLE WATER VALUES OVER AN INCH UPSTREAM IN
THE NORTHERN PLAINS. EXPC CLOUDS TO CONTINUE INCREASING EARLY THIS
MRNG ACROSS THE AREA. A FEW SHOWERS POSSIBLE EARLY IN VCNTY OF FRONT
BUT BETTER CHANCE LATER THIS MRNG WITH BEST CHANCE THIS AFTERNOON.
GFS AND ECMWF SHOWING BEST RUN TO RUN CONTINUITY WITH MID-LEVEL
FEATURES THIS AFTN AND EVE. INITIALLY THOUGHT I WOULD NEED TO LOWER
POPS IN SOME AREAS THIS AFTN AS LOW-MID LEVEL DEFORMATION ASSOCIATED
WITH SHORT WAVE INDICATED TO WEAKEN AS IT PASSES ACROSS SRN WI.
HOWEVER WITH MID-LEVEL WAVE EXPECTED TO SHARPEN AS IT PASSES ACROSS
SOUTHERN WI...AND IMPRESSIVE LAYER FN VECTOR RESPONSE TO
FRONTOGENETICAL FORCING...WL CONTINUE HIGH POPS THIS AFTN. LAYER
Q-VECTOR CONVERGENCE TIED TO SURGE OF HIGHER LAYER RH PASSES THRU
SRN WI DURING THE AFTN AS WELL...WHICH IS ALSO TIED TO PERIOD OF
ENHANCED FORCING FROM RIGHT ENTRANCE REGION OF 3H JET. BETTER
CHANCE FOR MORE PROLONGED SHOWERS IN NORTH CLOSER TO
DEFORMATION...AND IN THE SOUTHEAST WHERE MUCAPES MAY CLIMB TO OVER
500 J/KG ALONG CDFNT. WL CONTINUE TO MENTION SMALL T THREAT TODAY.
SHWRS WL END FROM WEST TO EAST ACROSS SRN WI FROM MID-AFTN THRU THE
EVE AS COOLER...DRIER AIR RUSHES IN FROM THE NORTH AND DEFORMATION
SLIDES OFF TO THE EAST. PARTIAL CLEARING AND CHILLY AIR WL ALLOW
TEMPS TO FALL INTO THE UPPER 30S IN THE WEST TONIGHT.
TUESDAY...FORECAST CONFIDENCE MEDIUM.
WEAK VORTICITY WITHIN THE AXIS OF THE 500MB TROUGH AND THE 850MB
THERMAL TROUGH WILL BE MOVING ACROSS WISCONSIN ON TUESDAY...MOST
LIKELY IN THE MORNING. GFS AND NAM MODEL SOUNDINGS STILL LOOK
CONDUCIVE FOR DIURNAL CUMULUS CLOUDS AND SOME ISOLATED SHOWERS OR
SPRINKLES...EVEN THOUGH THEY ARE NOT SHOWING MUCH/ANY QPF. THE 00Z
ECMWF CAME IN WITH 0.01 TO 0.03 ACROSS MUCH OF WI. COMPARISON OF
MODEL CU RULE INDICATES WIDESPREAD CLOUDS QUICKLY DEVELOPING IN THE
MORNING AND THEN DISSIPATING FROM WEST TO EAST EARLY IN THE
AFTERNOON AS THE VERY DRY AIR WORKS ITS WAY IN.
KEPT A SMALL CHANCE FOR LIGHT SHOWERS OR SPRINKLES IN THE FORECAST
ON TUESDAY. MAX TEMPS WILL ONLY BE IN THE UPPER 50S TO AROUND 60
WITH 925MB TEMPS AROUND 8C.
TUESDAY NIGHT...FORECAST CONFIDENCE HIGH.
CLEAR SKIES AND VERY COOL TEMPERATURES WILL SETTLE INTO SOUTHERN WI
ON TUESDAY NIGHT AS A RIDGE OF HIGH PRESSURE BRIEFLY MOVES ACROSS
THE REGION. THE NAM IS MORE BULLISH WITH WARM AIR ADVECTION IN
RETURN FLOW AROUND THE HIGH TUE NIGHT WHILE THE OTHER MODELS KEEP
925MB TEMPS AROUND 8C AND 850MB TEMPS AROUND 1C TO 2C. MIN TEMPS
SHOULD DROP INTO THE MID 30S INLAND.
CONTINUED MENTION OF PATCHY FROST IN THE FORECAST FOR MUCH OF THE
FORECAST AREA BUT KEEP IN MIND THAT PATCHY IS THE KEY WORD. WITH
SOIL TEMPS IN THE 60S TO LOW 70S AND POSSIBLY SOME HIGH CLOUDS
STREAMING IN LATE WITH THE WARM AIR ADVECTION KEEPING THE AREA
SLIGHTLY WARMER...ESPECIALLY IN THE WEST...THERE IS A LIMITED
POTENTIAL FOR FROST.
LONG TERM...
WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE MEDIUM.
ANOTHER UPPER TROUGH WITH A DECENT VORT MAX WILL CROSS WI WED
AFTERNOON/EVENING AND BRING ANOTHER CHANCE FOR SHOWERS. SHOWERS
WOULD BE SCATTERED IN NATURE AND PRECIP AMOUNTS WILL BE LIGHT.
TIGHT PRESSURE GRADIENT BETWEEN EXITING HIGH PRESSURE AND THE
SURFACE TROUGH APPROACHING WILL CREATE BREEZY SOUTH TO SOUTHWEST
WINDS WED AFTERNOON. WIND GUSTS OF 25 TO 30 MPH WILL BE POSSIBLE.
THE WINDS WILL ALSO USHER IN WARMER AIR...WITH HIGHS RANGING FROM
AROUND 70 IN THE WESTERN FORECAST AREA TO THE UPPER 60S EAST.
THE SURFACE FRONT WILL CLEAR SOUTHEAST WI BY 12Z THU AND ANY PRECIP
SHOULD BE OUT OF THE AREA BY THEN. NOT SURE WHAT TO EXPECT FOR CLOUD
COVER ON THURSDAY...EXCEPT IT LOOKS LIKE AT LEAST HIGH CLOUDS WILL
BE STREAMING OVER THE REGION DUE TO THE UPPER JET OVER NORTHERN
WISCONSIN. LOW LEVELS LOOK DRY AT THIS TIME.
FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM.
SEVERAL 500MB TROUGHS ASSOCIATED WITH DEEP LOW PRESSURE OVER HUDSON
BAY WILL SWING ACROSS THE UPPER GREAT LAKES REGION FOR MUCH OF THE
WEEKEND. MODELS SHOW THAT UPPER TROUGH SHIFTING EAST DURING THE DAY
ON SUNDAY. THIS MEANS COOL TEMPERATURES...PLENTY OF CLOUDS DURING
THE DAYTIME...A BRISK NORTHWEST BREEZE...AND A SMALL CHANCE OF
SHOWERS OR SPRINKLES FOR FRIDAY AND SATURDAY. THE SUN SHOULD BE OUT
MORE ON SUNDAY AS THE TROUGH MOVES AWAY.
AVIATION/12Z TAFS/...MID-LEVEL CLOUDS FILLING IN AHEAD OF
APPROACHING SFC FRONT OVER CENTRAL WI. EXPC CLOUDS TO CONTINUE TO
INCREASE EARLY THIS MRNG. THESE INCREASING CLOUDS AN INDICATOR OF
INCREASING LOW-MID LEVEL RH AND LOW LEVEL CONVERGENCE. GOES SOUNDER
INDICATED UPSTREAM PRECIPITABLE WATER VALUES OVER 1.0 INCH. HENCE
NEED TO WATCH FOR SHRA DEVELOPMENT AND ISOLD T ALONG PASSING FRONT.
EXPECT A SWATH OF SHRA AND ISOLD T TO SWEEP ACROSS TAF SITES THIS
AFTN AND EARLY EVE WHEN STRONGEST FORCING ASSOCD WITH MID-LEVEL
SHORT WAVE MOVES THRU. MAY BE A PERIOD OF MVFR CIGS AND VSBYS WITH
SHRA AND LOW LEVEL COLD AIR ADVECTION THIS AFTN AND EVENING BEFORE
CLEARING.
MARINE...COLD FRONT CUTTING ACROSS WI WL SWEEP ACROSS THE LAKE MI
NEARSHORE WATERS FROM LATE THIS MRNG THRU MID-LATE AFTN. SOUTHWEST
WINDS WL BRIEFLY TURN TO THE NORTH BUT WL BE PREDOMINANTLY NORTHWEST
AFT FROPA WITH A FEW HIGHER GUSTS IMMEDIATELY AFT FROPA. STRONG LOW
LEVEL COLD AIR ADVECTION TONIGHT WILL CREATE STEEP LOW LEVEL LAPSE
RATES OVER THE NEAR SHORE WATERS. THE UNSTABLE CONDITIONS ALONG WITH
A TIGHTENING PRESSURE GRADIENT SHOULD CAUSE WIND GUSTS TO REACH
SMALL CRAFT ADVY LEVELS...POSSIBLY LATER THIS AFTN...BUT MOSTLY TNGT
WHEN THE MOST UNSTABLE CONDITIONS ARE ANTICIPATED. WILL ISSUE SMALL
CRAFT ADVY FROM 21Z TODAY THRU 00Z/WED. STRONGEST WINDS GUSTS WL
LIKELY BE TNGT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM CDT
TUESDAY FOR LMZ643>646.
&&
$$
UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...MBK
TUESDAY THROUGH SUNDAY...MRC