Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/18/12
AREA FORECAST DISCUSSION
NWS MIAMI FL
121 PM EDT TUE OCT 16 2012
.AVIATION...
ALTHOUGH VFR CONDITIONS WILL PREVAIL THROUGH THE BULK OF THE
PERIOD...A FEW SHOWERS DEVELOPING THIS AFTERNOON COULD RESULT IN
A BRIEF PERIOD OR TWO WITH SUB VFR CIGS/VSBYS. THE LATEST HIRES
MODEL GUIDANCE REFLECTS THIS AND GENERALLY INDICATES THE BEST
COVERAGE SETTING UP ACROSS THE SOUTHERN HALF OF THE FL PENINSULA
THROUGH THE LATE AFTERNOON AND EARLY EVENING PERIODS.
THEREFORE...WILL CONTINUE TO INCLUDE VCSH FOR THESE TAF SITES
THROUGH THIS PERIOD TODAY. WINDS WILL REMAIN LIGHT THROUGH THE
PERIOD. FOR WEDNESDAY...RAIN CHANCES WILL SLIGHTLY INCREASE AS AN
UPPER TROUGH ADVANCES EWD ACROSS THE STATE. WILL INTRODUCE VCSH
THROUGH THE LATTER HALF OF THIS PACKAGE AS A RESULT.
&&
.PREV DISCUSSION... /ISSUED 939 AM EDT TUE OCT 16 2012/
UPDATE...
THE MORNING SURFACE ANALYSIS SHOWED A COLD FRONT EXTENDING
SOUTHWEST ACROSS THE FLORIDA PENINSULA FROM AROUND DAYTONA BEACH
TO JUST NORTH OF TAMPA. PLENTY OF DRY AIR WITH DEWPOINTS IN THE
LOWER 50S HAS ALREADY BEGUN TO SPREAD SOUTH INTO NORTHERN FLORIDA
IN ITS WAKE EARLY THIS MORNING. FARTHER SOUTH AHEAD OF THIS
BOUNDARY...A DECENT AMOUNT OF LOW-LEVEL MOISTURE WITH DEWPOINTS
REMAINING IN THE LOWER 70S WILL BE ANTICIPATED TODAY. THE MORNING
UPPER AIR SOUNDING IN MIAMI REFLECTED THIS MOISTURE UP TO AROUND
10 KFT OR 700 MB...THEN VERY DRY ABOVE THIS POINT. LOW-LEVEL WIND
PROFILE SHOWED NNE FLOW. AS A RESULT...THE LATEST HRRR AND WRF
MODEL REFLECTIVITIES INDICATE THE BEST CHANCE FOR MAINLY ISOLATED
SHOWERS LATER THIS AFTERNOON AND EVENING ACROSS THE SOUTHERN
EXTENT OF THE FL PENINSULA TODAY. FOR THE MORNING UPDATE...WE WILL
SLIGHTLY INCREASE THE AFTERNOON RAINFALL CHANCES OVER THESE SRN
AREAS AND CONTINUE THEM INTO THE EARLY EVENING HOURS.
OTHERWISE...THE PREVIOUS FORECAST PACKAGE REMAINS ON TRACK. 85/AG
PREV DISCUSSION... /ISSUED 727 AM EDT TUE OCT 16 2012/
AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. A FEW SHRA POSSIBLE THIS
AFTERNOON MAINLY OVER THE INTERIOR WITH STEERING FLOW TO THE SOUTH.
LATEST HIGH RESOLUTION SHORT TERM GUIDANCE SUGGESTS THE DEVELOPMENT
WILL BE LATE AND MOSTLY FROM BROWARD COUNTY AND TO THE SOUTH SO
PLACED VCSH IN FOR THOSE TERMINALS AND REMOVED FROM THE KAPF TAF.
OFFSHORE LIGHT WIND FLOW ALONG BOTH COASTS THIS MORNING WILL BECOME
ONSHORE ALONG THE E CST AFT 15-16Z AND AFT 17-18Z AT KAPF AND THEN
OFFSHORE ONCE AGAIN THIS EVENING. /KOB
PREV DISCUSSION... /ISSUED 351 AM EDT TUE OCT 16 2012/
SHORT TERM (TODAY-THURSDAY)...
E COAST UPPER TROUGH LIFTS TO THE NE PULLING HURRICANE RAFAEL NORTH
-WARD WHILE THE ASSOCIATED COLD FRONT CURRENTLY OVER N FLA...SLOWLY
MOVES SOUTHWARD AS THE UPPER FLOW BECOMES ZONAL. BUT OVERNIGHT AND
INTO EARLY WEDNESDAY MORNING ANOTHER SHORT WAVE DIVES INTO THE SE
U.S. AND LIFTS NE BUT THE FRONT LIMPS INTO S FLA BY WED MORNING
POSSIBLY STALLING AND WASHING OUT. HIGH PRESSURE THEN BUILDS OVER
THE EASTERN U.S. THURSDAY. PLENTY OF DRY AIR MOVING OVER S FLA BUT
ENOUGH MOISTURE IN PLACE TO TRIGGER SHOWER ACTIVITY THIS AFTERNOON
ACROSS MAINLY THE EASTERN HALF OF THE S FLA PENINSULA. ON WEDNESDAY
WITH THE STALLING/DISSIPATING BOUNDARY AND POSSIBLE INFLUENCE OF
THE SHORT WAVE CROSSING ACROSS N FLA...THERE MAY BE A CHANCE OF
SHOWERS AND SOME THUNDERSTORMS ACROSS THE AREA WITH THE BETTER
CHANCE OF PRECIPITATION INTERIOR AND E DUE TO WESTERLY STEERING
FLOW. ON THURSDAY...SOME DRIER AIR MOVES OVER S FLA AGAIN AND
WITH A MINOR DECREASE IN POPS.
MIAMI BEACH HAD SOME COASTAL FLOODING ON MONDAY WITH SOME MINOR
INUNDATION OF SOME ROADWAYS DURING HIGH TIDE. WITH WATER LEVELS
STILL RUNNING A BIT ABOVE NORMAL...DURING THE HIGH TIDE CYCLE TODAY
WHICH IS BETWEEN 9 AND 10 AM...SOME MINOR FLOODING MAY OCCUR
AGAIN. WITH DECREASING WINDS AND WITH TIDES RETURNING TO NORMAL
THIS POTENTIAL FLOODING AT MIAMI BEACH WILL DIMINISH THROUGH THE
WEEK. LITTLE IN THE WAY OF ADDITION RAINFALL IS EXPECTED TODAY BUT A
POTENTIAL OF HEAVIER RAINFALL ON WEDNESDAY THAT COULD BECOME
CONCENTRATED AND THE ADDITIONAL RAINFALL COULD RESULT IN ADDITIONAL
FLOODING OR STANDING WATER CONCERNS. SOMETHING TO WATCH.
LONG TERM (FRIDAY-MONDAY)...
A STRONG CLOSED MID/UPPER LOW DIVES INTO THE GREAT LAKES REGION
FRIDAY AND SATURDAY THEN LIFTS NE INTO E CANADA AS A HIGH PRESSURE
RIDGE MOVES EASTWARD AND OVER THE E U.S. BY EARLY NEXT WEEK. THE
ASSOCIATED COLD FRONT...BASED ON GFS/ECMWF COMPARISON...APPEARS TO
NOT NEAR S FLA. SO...MOISTURE REMAINS IN PLACE THROUGH THE PERIOD
WITH WARM, HUMID CONDITIONS PREVAILING THROUGH THE FORECAST PERIOD
ALONG WITH A DAILY CHANCE OF SHOWERS/TSTORMS. WITH WESTERLY STEERING
WINDS THE INTERIOR AND E WILL BE FAVORED.
MARINE...ATLC SEAS OF 2 TO 4 FEET...ESPECIALLY OFF OF PALM BEACH
COUNTY...THROUGH TONIGHT THEN 2 TO 3 FEET ALL ATLC WATERS THROUGH
THURSDAY WHICH WILL BECOME 2 FEET OR LESS FRIDAY INTO THE EARLY
WEEKEND. SEAS INCREASE 2 TO 4 FEET BY LATE SUNDAY INTO MONDAY. WINDS
LESS THAN 15 KNOTS THROUGH SATURDAY NIGHT THEN INCREASING TO 15
KNOTS OR HIGHER LATE SUNDAY INTO MONDAY.
FIRE WEATHER...RELATIVE HUMIDITIES ARE FORECAST TO REMAIN WELL
ABOVE CRITICAL LEVELS WITH NO RED FLAG CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 87 72 87 / 10 40 20 30
FORT LAUDERDALE 76 87 75 87 / 10 40 20 30
MIAMI 75 87 74 87 / 10 40 20 30
NAPLES 72 84 71 86 / 0 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...55/CWC
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MIAMI FL
939 AM EDT TUE OCT 16 2012
.UPDATE...
THE MORNING SURFACE ANALYSIS SHOWED A COLD FRONT EXTENDING
SOUTHWEST ACROSS THE FLORIDA PENINSULA FROM AROUND DAYTONA BEACH
TO JUST NORTH OF TAMPA. PLENTY OF DRY AIR WITH DEWPOINTS IN THE
LOWER 50S HAS ALREADY BEGUN TO SPREAD SOUTH INTO NORTHERN FLORIDA
IN ITS WAKE EARLY THIS MORNING. FARTHER SOUTH AHEAD OF THIS
BOUNDARY...A DECENT AMOUNT OF LOW-LEVEL MOISTURE WITH DEWPOINTS
REMAINING IN THE LOWER 70S WILL BE ANTICIPATED TODAY. THE MORNING
UPPER AIR SOUNDING IN MIAMI REFLECTED THIS MOISTURE UP TO AROUND
10 KFT OR 700 MB...THEN VERY DRY ABOVE THIS POINT. LOW-LEVEL WIND
PROFILE SHOWED NNE FLOW. AS A RESULT...THE LATEST HRRR AND WRF
MODEL REFLECTIVITIES INDICATE THE BEST CHANCE FOR MAINLY ISOLATED
SHOWERS LATER THIS AFTERNOON AND EVENING ACROSS THE SOUTHERN
EXTENT OF THE FL PENINSULA TODAY. FOR THE MORNING UPDATE...WE WILL
SLIGHTLY INCREASE THE AFTERNOON RAINFALL CHANCES OVER THESE SRN
AREAS AND CONTINUE THEM INTO THE EARLY EVENING HOURS.
OTHERWISE...THE PREVIOUS FORECAST PACKAGE REMAINS ON TRACK. 85/AG
&&
.PREV DISCUSSION... /ISSUED 727 AM EDT TUE OCT 16 2012/
AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. A FEW SHRA POSSIBLE THIS
AFTERNOON MAINLY OVER THE INTERIOR WITH STEERING FLOW TO THE SOUTH.
LATEST HIGH RESOLUTION SHORT TERM GUIDANCE SUGGESTS THE DEVELOPMENT
WILL BE LATE AND MOSTLY FROM BROWARD COUNTY AND TO THE SOUTH SO
PLACED VCSH IN FOR THOSE TERMINALS AND REMOVED FROM THE KAPF TAF.
OFFSHORE LIGHT WIND FLOW ALONG BOTH COASTS THIS MORNING WILL BECOME
ONSHORE ALONG THE E CST AFT 15-16Z AND AFT 17-18Z AT KAPF AND THEN
OFFSHORE ONCE AGAIN THIS EVENING. /KOB
PREV DISCUSSION... /ISSUED 351 AM EDT TUE OCT 16 2012/
SHORT TERM (TODAY-THURSDAY)...
E COAST UPPER TROUGH LIFTS TO THE NE PULLING HURRICANE RAFAEL NORTH
-WARD WHILE THE ASSOCIATED COLD FRONT CURRENTLY OVER N FLA...SLOWLY
MOVES SOUTHWARD AS THE UPPER FLOW BECOMES ZONAL. BUT OVERNIGHT AND
INTO EARLY WEDNESDAY MORNING ANOTHER SHORT WAVE DIVES INTO THE SE
U.S. AND LIFTS NE BUT THE FRONT LIMPS INTO S FLA BY WED MORNING
.POSSIBLY STALLING AND WASHING OUT. HIGH PRESSURE THEN BUILDS OVER
THE EASTERN U.S. THURSDAY. PLENTY OF DRY AIR MOVING OVER S FLA BUT
ENOUGH MOISTURE IN PLACE TO TRIGGER SHOWER ACTIVITY THIS AFTERNOON
ACROSS MAINLY THE EASTERN HALF OF THE S FLA PENINSULA. ON WEDNESDAY
.WITH THE STALLING/DISSIPATING BOUNDARY AND POSSIBLE INFLUENCE OF
THE SHORT WAVE CROSSING ACROSS N FLA...THERE MAY BE A CHANCE OF
SHOWERS AND SOME THUNDERSTORMS ACROSS THE AREA WITH THE BETTER
CHANCE OF PRECIPITATION INTERIOR AND E DUE TO WESTERLY STEERING
FLOW. ON THURSDAY...SOME DRIER AIR MOVES OVER S FLA AGAIN AND
WITH A MINOR DECREASE IN POPS.
MIAMI BEACH HAD SOME COASTAL FLOODING ON MONDAY WITH SOME MINOR
INUNDATION OF SOME ROADWAYS DURING HIGH TIDE. WITH WATER LEVELS
STILL RUNNING A BIT ABOVE NORMAL...DURING THE HIGH TIDE CYCLE TODAY
.WHICH IS BETWEEN 9 AND 10 AM...SOME MINOR FLOODING MAY OCCUR
AGAIN. WITH DECREASING WINDS AND WITH TIDES RETURNING TO NORMAL
.THIS POTENTIAL FLOODING AT MIAMI BEACH WILL DIMINISH THROUGH THE
WEEK. LITTLE IN THE WAY OF ADDITION RAINFALL IS EXPECTED TODAY BUT A
POTENTIAL OF HEAVIER RAINFALL ON WEDNESDAY THAT COULD BECOME
CONCENTRATED AND THE ADDITIONAL RAINFALL COULD RESULT IN ADDITIONAL
FLOODING OR STANDING WATER CONCERNS. SOMETHING TO WATCH.
LONG TERM (FRIDAY-MONDAY)...
A STRONG CLOSED MID/UPPER LOW DIVES INTO THE GREAT LAKES REGION
FRIDAY AND SATURDAY THEN LIFTS NE INTO E CANADA AS A HIGH PRESSURE
RIDGE MOVES EASTWARD AND OVER THE E U.S. BY EARLY NEXT WEEK. THE
ASSOCIATED COLD FRONT...BASED ON GFS/ECMWF COMPARISON...APPEARS TO
NOT NEAR S FLA. SO...MOISTURE REMAINS IN PLACE THROUGH THE PERIOD
WITH WARM, HUMID CONDITIONS PREVAILING THROUGH THE FORECAST PERIOD
ALONG WITH A DAILY CHANCE OF SHOWERS/TSTORMS. WITH WESTERLY STEERING
WINDS THE INTERIOR AND E WILL BE FAVORED.
MARINE...ATLC SEAS OF 2 TO 4 FEET...ESPECIALLY OFF OF PALM BEACH
COUNTY...THROUGH TONIGHT THEN 2 TO 3 FEET ALL ATLC WATERS THROUGH
THURSDAY WHICH WILL BECOME 2 FEET OR LESS FRIDAY INTO THE EARLY
WEEKEND. SEAS INCREASE 2 TO 4 FEET BY LATE SUNDAY INTO MONDAY. WINDS
LESS THAN 15 KNOTS THROUGH SATURDAY NIGHT THEN INCREASING TO 15
KNOTS OR HIGHER LATE SUNDAY INTO MONDAY.
FIRE WEATHER...RELATIVE HUMIDITIES ARE FORECAST TO REMAIN WELL
ABOVE CRITICAL LEVELS WITH NO RED FLAG CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 75 87 72 / 10 10 40 20
FORT LAUDERDALE 88 76 87 75 / 10 10 40 20
MIAMI 88 75 87 74 / 10 10 40 20
NAPLES 88 72 84 71 / - 0 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1022 PM EDT WED OCT 17 2012
.UPDATE...
CONTINUE TO MONITOR TRENDS ON IR SATELLITE AND RADAR OF CONVECTION
IN THE MID-SOUTH AS IT ENTERS WESTERN TENNESSEE. FORECAST HAS BEEN
UPDATED TO ACCOUNT FOR EARLIER TIMING OF THIS SYSTEM...ENTERING
NORTH GEORGIA EARLY THURSDAY MORNING. LATEST LOCAL WRF AND
NATIONAL HRRR MODEL GUIDANCE CONTINUES TO INDICATE THAT ACTIVITY
SHOULD BEGIN TO FALL APART AS IT MOVES THROUGH METRO ATLANTA
BETWEEN 08Z AND 10Z THURSDAY MORNING.
AVAILABLE INSTABILITY SHOULD ALLOW THE LINE TO PRODUCE SOME
THUNDERSTORMS IN NORTH GEORGIA TONIGHT. CANNOT RULE OUT AN
ISOLATED EMBEDDED TORNADO AS THIS LINE PUSHES THROUGH...WITH 0-1
KM SHEAR VALUES NEARING 55 KTS...ALTHOUGH THE THREAT OF A STRAIGHT
LINE WIND EVENT IS SLIGHTLY MORE LIKELY GIVEN THE LITTLE
DIRECTIONAL 0-1 KM SHEAR IN NORTH GEORGIA OVERNIGHT ACCORDING TO
THE 22Z HRRR RUN.
RAG/37
&&
.PREV DISCUSSION...
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
/ISSUED AT 255 PM EDT WED OCT 17 2012/
UPPER LEVEL FLOW TRANSITIONING FROM A FLAT...NEARLY ZONAL...PATTERN
ACROSS THE CONTINENTAL U.S. TO A RELATIVELY STATIC...HIGH AMPLITUDE
PATTERN AS A STRONG SHORT WAVE DIVING OUT OF CANADA DIGS A DEEP
UPPER LOW INTO THE UPPER MISSISSIPPI VALLEY TONIGHT. STRONG...DEEP
SURFACE LOW ASSOCIATED WITH THIS SYSTEM REMAINS WELL NORTH OF
GEORGIA BUT DRIVES A COLD FRONT INTO NORTHWEST GEORGIA EARLY
THURSDAY. MOISTURE IS VERY LIMITED CURRENTLY...BUT DEEPENING NATURE
OF THE SYSTEM PULLS SUFFICIENT MOISTURE NORTH AHEAD OF THE FRONT FOR
HIGH CHANCE TO LIKELY POPS ALONG AND JUST AHEAD OF THE FRONT
SWEEPING NORTHWEST TO SOUTHEAST ACROSS THE FORECAST AREA FROM LATE
TONIGHT THROUGH THURSDAY EVENING. RIGHT NOW ONLY THE NAM IS
GENERATING ENOUGH INSTABILITY FOR THUNDER...SO I WILL KEEP
THUNDERSTORMS LIMITED TO SLIGHT CHANCE. PRECIPITATION PUSHES
SOUTHEAST OUT OF THE FORECAST AREA THURSDAY NIGHT AS DRIER AIR
SWEEPS IN BEHIND THE FRONT. RIGHT NOW MODEL TRENDS ARE FOR CLEARING
SKIES THURSDAY NIGHT THROUGH FRIDAY...HOWEVER THE DEEP UPPER LOW
REMAINS ESSENTIALLY STATIONARY OVER THE SOUTHERN GREAT LAKES/WESTERN
OHIO VALLEY SO WE WILL NEED TO KEEP AN EYE ON TRENDS FOR POTENTIALLY
MORE CLOUD COVER ACROSS AT LEAST NORTH GEORGIA THROUGH THE PERIOD.
20
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO CHANGES FROM PREVIOUS LONG TERM. PREVIOUS LONG TERM DISCUSSION
FOLLOWS.
/ISSUED AT 336 AM EDT WED OCT 17 2012/
IN THE WAKE OF THE FRONTAL SYSTEM EXITING THE FORECAST AREA
THURSDAY NIGHT...THE UPPER LEVEL TROUGH AXIS OF A BROAD UPPER
CLOSED LOW CENTERED ACROSS THE GREAT LAKES SHOULD REMAIN WEST OF
THE AREA UNTIL THE SATURDAY NIGHT/EARLY SUNDAY TIME PERIOD.
GUIDANCE IS IN OVERALL AGREEMENT WITH THE MOISTURE FIELD STAYING
NORTH OF THE AREA WITH NO SIGNIFICANT SHORTWAVE INFLUENCE. THE
BEST CHANCE FOR ANY PRECIP WOULD BE FRIDAY NIGHT WITH A WEAK
SHORTWAVE IMPULSE ROTATING THROUGH GEORGIA. AT THIS POINT...IT
LOOKS LIKE IF ANY LOCATION HAD A CHANCE FOR PRECIP IT WOULD BE THE
NORTHERN PORTION OF THE AREA CLOSER TO THE HIGHER PROGGED LAYER RH
VALUES. HOWEVER...WITH THE ENERGY BEING A BIT TOO FAR SOUTH FROM
THE MOISTURE AND A SFC HIGH FILTERING IN FROM THE WEST...IT SHOULD
RESULT IN ONLY AN ENHANCEMENT IN CLOUD COVERAGE SO WILL KEEP A DRY
FORECAST. THE DRY AND PLEASANT WEATHER SHOULD PERSIST THROUGH THE
REMAINDER OF THE LONG TERM AS GUIDANCE IS IN GOOD CONSENSUS WITH A
1020-1022 MB SFC HIGH SETTING UP ACROSS THE CAROLINAS BY THE END
OF THE WEEKEND AND PERSISTING THROUGH TUESDAY. THIS SHOULD BRING
WEAK SOUTHEASTERLY TO SOUTHERLY FLOW ACROSS THE AREA.
FOR TEMPS...LATEST MEX GUIDANCE SEEMED SLIGHTLY COOL ON DAYTIME MAX
VALUES SO STAYED A BIT HIGHER. OTHERWISE...SHOULD SEE OVERNIGHT LOWS
MAINLY IN THE 40S HEADING INTO THE WEEKEND...THEN WARMING UP
GRADUALLY INTO THE UPPER 40S AND LOW 50S BY EARLY NEXT WEEK. HIGHS
WILL START OUT COOL IN THE UPPER 60S TO 70S AND GRADUALLY WARM INTO
THE LOW TO UPPER 70S BY SUNDAY.
BAKER
AVIATION...
00Z UPDATE.../ISSUED 800 PM EDT WED OCT 17 2012/
VFR CONDITIONS EXPECTED THROUGH 06Z. CLOUD COVER THICKENING OVER MS
RVR VLY..BUT AT THE SAME TIME LIFTING NEWD. MVFR CIGS AND VSBYS
MOVING INTO NORTHWEST GA NEAR 06Z AND APPROACHING ATL BY 09Z WITH
BAND OF MVFR CIGS/VSBYS AND SHRA ALONG A COLD FRONT...SPREADING
SOUTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. S-SE WINDS
5-9KT...DECREASING TO 3-5KT AFTER 01Z...SHIFTING TO SW-W BEHIND THE
FRONT AND INCREASING TO 7-10KT...GUSTING 14-18KT...THURSDAY.
//ATL CONFIDENCE...00Z UPDATE...
HIGH ON ALL ELEMENTS THROUGH 06Z.
LOW TO MEDIUM ON TIMING...CIGS HEIGHT AND SHOWERS FOR THURSDAY.
MEDIUM-HIGH ON TIMING OF WIND SHIFT THURSDAY.
37
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 54 73 45 73 / 20 50 10 5
ATLANTA 59 73 49 72 / 50 60 5 0
BLAIRSVILLE 50 67 40 66 / 60 60 5 0
CARTERSVILLE 52 71 40 71 / 60 60 5 0
COLUMBUS 59 76 50 77 / 20 40 10 5
GAINESVILLE 56 72 47 70 / 50 50 5 0
MACON 57 77 46 76 / 10 50 10 5
ROME 52 71 40 73 / 60 50 5 0
PEACHTREE CITY 54 73 42 73 / 40 50 5 5
VIDALIA 58 81 60 80 / 5 40 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...37
LONG TERM....RAG
AVIATION...37
AREA FORECAST DISCUSSION
NWS LINCOLN IL
900 PM CDT WED OCT 17 2012
.DISCUSSION...
ISSUED 855 PM CDT WED OCT 17 2012
UPDATING THE FORECAST TONIGHT FOR FASTER TRENDS OF SHIFTING THE
SHOWERS AND THUNDERSTORMS TO THE EAST AND ALSO INCREASING WIND
GUSTS ESPECIALLY THIS EVENING SINCE GETTING GUSTS IN THE 30S AT
TIMES. LOWS IN THE LOWER TO MIDDLE 40S BY DAWN LOOK ON TRACK.
A VIGOROUS COLD FRONT RACING EAST TOWARD I-57 AT MID EVENING HAD A
BAND OF SHOWERS AND A FEW THUNDERSTORMS OVER EASTERN IL WITH
MODERATE TO HEAVY RAIN AND GUSTY WINDS AS HIGH AS 30 TO 40 MPH.
HAD A FEW WIND DAMAGE REPORTS BETWEEN 630 PM AND 730 PM NEAR
WILLIAMSVILLE AND CLINTON. THE COLD FRONT ARCHES BACK TO A STRONG
983 MB LOW PRESSURE OVER NW MN. A DEEPENING 535 DM 500 MB LOW WAS
ALONG THE DAKOTAS/MN BORDER. COLD FRONT NEAR I-57 TO RACE EAST TO
THE INDIANA BORDER BY MIDNIGHT AND JUST EAST OF INDIANA BY 12Z/7
AM THU. SHOWERS AND ISOLATED THUNDERSTORMS TO DIMINISH QUICKLY
BEHIND THE FRONT BY EARLY OVERNIGHT. SOME CLEARING OVER MO WORKS
IT WAS EASTWARD ACROSS CENTRAL/SE IL OVERNIGHT AS AREA GETS DRY
SLOTTED FOR A TIME OVERNIGHT. BREEZY SOUTH WINDS AHEAD OF THE COLD
FRONT TO TURN BREEZY WEST BEHIND THE COLD FRONT WITH GUSTS
GRADUALLY DIMINISHING DURING OVERNIGHT...BUT SW WINDS TO PICK UP
AGAIN DURING THU MORNING. TEMPS DROP INTO THE MID 50S BEHIND THE
COLD FRONT FROM I-55 WEST WHILE LOWER 60S AHEAD OF THE FRONT.
TEMPS SHOULD SLIP INTO THE LOW TO MID 40S BY DAWN THU EXCEPT UPPER
40S NEAR THE WABASH RIVER BY LAWRENCEVILLE.
07
&&
.AVIATION...
ISSUED 650 PM CDT WED OCT 17 2012
IFR TO MVFR CEILINGS AND VSBYS EXPECTED WITH A BAND OF SHOWERS AND
A FEW EMBEDDED THUNDERSTORMS AT PIA AND SPI AHEAD OF A COLD FRONT
IN WESTERN IL RACING EAST INTO EASTERN IL THIS EVENING...REACHING
BMI AND DEC BY 01Z AND CMI BY 02Z. ALSO HAVE SCATTERED SHOWERS AND
A FEW THUNDERSTORM AHEAD OF THIS BAND OVER EASTERN IL MAINLY FROM
DEC AND CMI EAST SO INCLUDED NEXT FEW HOURS THERE AS WELL. BREEZY
SOUTH WINDS TO TURN WEST BEHIND THE LINE OF SHOWERS AND
THUNDERSTORMS DURING THIS EVENING AND HAS ALREADY OCCURRED AT SPI
WITH WEST WIND GUST OF 34 KTS. USED HRRR MODEL END CONVECTION FROM
WEST TO EAST BETWEEN 03Z- 06Z THEN SCATTERING OUT LOW CLOUDS EARLY
OVERNIGHT FROM WEST TO EAST A FEW HOURS AFTER RAIN ENDS. STRONG
537 DM 500 MB LOW ALONG THE EASTERN DAKOTAS BORDER TO DEEPEN TO
532 DM BY 00Z/7 PM THU NEAR DUBUQUE. THIS TO SPREAD BROKEN CLOUDS
3-5KT SE ACROSS CENTRAL IL DURING MID/LATE THU AFTERNOON. STRONG
SW WINDS 15-20 KTS WITH GUSTS OF 25-30 KTS EXPECTED THU DUE TO
TIGHT PRESSURE GRADIENT WITH 995 MB LOW PRESSURE OVER THE UPPER MS
VALLEY.
07
&&
.PREV DISCUSSION...
ISSUED 244 PM CDT WED OCT 17 2012
SHORT TERM...TONIGHT THROUGH SATURDAY
STRONG COLD FRONT CURRENTLY EXTENDING FROM WESTERN WISCONSIN INTO
NORTHERN MISSOURI WILL SWING EASTWARD THIS EVENING...BRINGING A
PERIOD OF SHOWERS AND THUNDERSTORMS TO CENTRAL ILLINOIS. SCATTERED
CONVECTION HAS ALREADY DEVELOPED IN THE WARM AIR ADVECTION REGIME
ACROSS THE AREA THIS AFTERNOON...HOWEVER THE MAIN EVENT WILL OCCUR
WITH FRONTAL PASSAGE THIS EVENING. HIGH-RES MODELS HAVE SLOWED THE
EASTWARD PROGRESS OF THE FRONT FROM PREVIOUS RUNS...WITH THE HRRR
NOW FEATURING A LINE OF SHOWERS/STORMS ALONG OR JUST EAST OF THE
ILLINOIS RIVER BY 00Z. STORMS WILL RAPIDLY PROGRESS EASTWARD...EXITING
INTO INDIANA BY AROUND 06Z. GIVEN MEAGER INSTABILITY DUE TO
EXTENSIVE CLOUD COVER...AM NOT EXPECTING WIDESPREAD SEVERE ACROSS
CENTRAL ILLINOIS. GREATEST INSTABILITY AND STRONGEST WIND-SHEAR
CONTINUES TO BE FOCUSED FURTHER SOUTH...FROM SOUTHERN ILLINOIS
INTO THE OZARKS. GIVEN INCREASING WIND SPEEDS ALOFT WITH
APPROACHING JET STREAK...THINK A FEW OF THE STRONGER CELLS COULD
PRODUCE GUSTY WINDS BETWEEN 5 PM AND MIDNIGHT. HEAVY RAINFALL
WILL ALSO BE A POSSIBILITY WITH THE STORMS...AS PRECIPITABLE WATER
VALUES CLIMB INTO THE 1 TO 1.50 INCH RANGE. AS A RESULT...AM
ANTICIPATING BETWEEN ONE HALF AND ONE INCH OF RAIN AS THE LINE
PASSES THROUGH...WITH LOCALLY HIGHER AMOUNTS EAST OF I-55. ONCE
FRONT PUSHES OFF TO THE EAST...BREEZY AND COOLER WEATHER WILL
STREAM INTO THE REGION AFTER MIDNIGHT. FORECAST SOUNDINGS SUGGEST
CLEARING SKIES ACROSS THE ENTIRE AREA BY DAWN...ALLOWING LOW TEMPS
TO DROP INTO THE LOWER TO MIDDLE 40S.
AFTER A MOSTLY SUNNY START TO THE DAY...CLOUDS WILL INCREASE FROM
THE NW BY LATE THURSDAY MORNING...AS A DEEP UPPER LOW OVER THE
NORTHERN PLAINS DIGS SOUTHEASTWARD. NAM/GFS BOTH BRING SHOWERS
INTO THE NORTHWEST CWA BY AFTERNOON...WITH PRECIP SPREADING ACROSS
THE ENTIRE AREA THURSDAY NIGHT. HIGHLY DYNAMIC SYSTEM AND AMPLE
LOW/MID-LEVEL MOISTURE WARRANTS LIKELY POPS ACROSS THE CENTRAL AND
NORTHERN ZONES...WITH ONLY CHANCE POPS ALONG/SOUTH OF I-70 FURTHER
AWAY FROM THE BEST FORCING. COOL/SHOWERY WEATHER WILL CONTINUE
INTO FRIDAY AS WELL...AS LOW TRACKS INTO THE SOUTHERN GREAT LAKES.
WILL CONTINUE WITH HIGH CHANCE TO LIKELY POPS FOR SHOWERS ACCORDINGLY.
DUE TO CLOUD COVER AND BRISK NORTHWESTERLY WINDS...HIGH TEMPS ON
FRIDAY WILL REMAIN IN THE 50S.
IMPROVING CONDITIONS WILL ARRIVE BY SATURDAY...AS LOW MOVES FURTHER
AWAY AND UPPER HEIGHTS BEGIN TO RISE. SUNSHINE AND WEAK RETURN
FLOW WILL HELP BOOST HIGHS BACK INTO THE 60S.
LONG TERM...SUNDAY THROUGH WEDNESDAY
EXTENDED FORECAST CONTINUES TO TREND WARMER...AS 12Z 17 OCT MODELS
ADVERTISE UPPER TROUGH DEVELOPING ACROSS THE WESTERN CONUS AND
RIDGE BUILDING DOWNSTREAM OVER THE MIDWEST/OHIO RIVER VALLEY.
ECMWF REMAINS THE MOST AMPLIFIED MODEL...KEEPING UPPER HEIGHTS
QUITE HIGH ACROSS THE REGION THROUGH THE MIDDLE OF NEXT WEEK.
THE GFS...WHICH HAD PREVIOUSLY BEEN LESS AMPLIFIED WITH THE
TROUGH/RIDGE PATTERN...IS NOW BEGINNING TO LOOK MORE LIKE THE
ECMWF. THE MAIN QUESTION IN THE EXTENDED WILL BE WHERE THE
PREVAILING BAROCLINIC ZONE SETS UP BETWEEN A COOLER AIRMASS TO THE
NORTHWEST AND WARMER AIR TO THE SOUTHEAST. RECENT FORECASTS HAVE
TRENDED TOWARD THE ECMWF...WHICH KEEPS THE FRONT STALLED ACROSS
NORTHERN SECTIONS OF IOWA/ILLINOIS EARLY NEXT WEEK. LATEST RUN OF
THE ECMWF SHOWS GOOD CONSISTENCY FROM PREVIOUS SOLUTION...WHILE
GFS IS BEGINNING TO TREND NORTHWARD WITH THE FRONT AS WELL. AS A
RESULT...HAVE WARMED TEMPS MONDAY THROUGH WEDNESDAY TO FEATURE
DAILY HIGHS IN THE 70S. HAVE ALSO TRIMMED POPS...WITH ONLY LOW
CHANCE POPS MENTIONED ACROSS THE NORTHWEST CWA MONDAY INTO
TUESDAY. IF ECMWF PANS OUT...POPS MAY EVENTUALLY NEED TO BE
REMOVED ALTOGETHER AND TEMPS MAY NEED TO BE ADJUSTED UPWARD EVEN
FURTHER.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
649 PM CDT WED OCT 17 2012
.DISCUSSION...
ISSUED 244 PM CDT WED OCT 17 2012
SHORT TERM...TONIGHT THROUGH SATURDAY
STRONG COLD FRONT CURRENTLY EXTENDING FROM WESTERN WISCONSIN INTO
NORTHERN MISSOURI WILL SWING EASTWARD THIS EVENING...BRINGING A
PERIOD OF SHOWERS AND THUNDERSTORMS TO CENTRAL ILLINOIS. SCATTERED
CONVECTION HAS ALREADY DEVELOPED IN THE WARM AIR ADVECTION REGIME
ACROSS THE AREA THIS AFTERNOON...HOWEVER THE MAIN EVENT WILL OCCUR
WITH FRONTAL PASSAGE THIS EVENING. HIGH-RES MODELS HAVE SLOWED THE
EASTWARD PROGRESS OF THE FRONT FROM PREVIOUS RUNS...WITH THE HRRR
NOW FEATURING A LINE OF SHOWERS/STORMS ALONG OR JUST EAST OF THE
ILLINOIS RIVER BY 00Z. STORMS WILL RAPIDLY PROGRESS EASTWARD...EXITING
INTO INDIANA BY AROUND 06Z. GIVEN MEAGER INSTABILITY DUE TO
EXTENSIVE CLOUD COVER...AM NOT EXPECTING WIDESPREAD SEVERE ACROSS
CENTRAL ILLINOIS. GREATEST INSTABILITY AND STRONGEST WIND-SHEAR
CONTINUES TO BE FOCUSED FURTHER SOUTH...FROM SOUTHERN ILLINOIS
INTO THE OZARKS. GIVEN INCREASING WIND SPEEDS ALOFT WITH
APPROACHING JET STREAK...THINK A FEW OF THE STRONGER CELLS COULD
PRODUCE GUSTY WINDS BETWEEN 5 PM AND MIDNIGHT. HEAVY RAINFALL
WILL ALSO BE A POSSIBILITY WITH THE STORMS...AS PRECIPITABLE WATER
VALUES CLIMB INTO THE 1 TO 1.50 INCH RANGE. AS A RESULT...AM
ANTICIPATING BETWEEN ONE HALF AND ONE INCH OF RAIN AS THE LINE
PASSES THROUGH...WITH LOCALLY HIGHER AMOUNTS EAST OF I-55. ONCE
FRONT PUSHES OFF TO THE EAST...BREEZY AND COOLER WEATHER WILL
STREAM INTO THE REGION AFTER MIDNIGHT. FORECAST SOUNDINGS SUGGEST
CLEARING SKIES ACROSS THE ENTIRE AREA BY DAWN...ALLOWING LOW TEMPS
TO DROP INTO THE LOWER TO MIDDLE 40S.
AFTER A MOSTLY SUNNY START TO THE DAY...CLOUDS WILL INCREASE FROM
THE NW BY LATE THURSDAY MORNING...AS A DEEP UPPER LOW OVER THE
NORTHERN PLAINS DIGS SOUTHEASTWARD. NAM/GFS BOTH BRING SHOWERS
INTO THE NORTHWEST CWA BY AFTERNOON...WITH PRECIP SPREADING ACROSS
THE ENTIRE AREA THURSDAY NIGHT. HIGHLY DYNAMIC SYSTEM AND AMPLE
LOW/MID-LEVEL MOISTURE WARRANTS LIKELY POPS ACROSS THE CENTRAL AND
NORTHERN ZONES...WITH ONLY CHANCE POPS ALONG/SOUTH OF I-70 FURTHER
AWAY FROM THE BEST FORCING. COOL/SHOWERY WEATHER WILL CONTINUE
INTO FRIDAY AS WELL...AS LOW TRACKS INTO THE SOUTHERN GREAT LAKES.
WILL CONTINUE WITH HIGH CHANCE TO LIKELY POPS FOR SHOWERS ACCORDINGLY.
DUE TO CLOUD COVER AND BRISK NORTHWESTERLY WINDS...HIGH TEMPS ON
FRIDAY WILL REMAIN IN THE 50S.
IMPROVING CONDITIONS WILL ARRIVE BY SATURDAY...AS LOW MOVES FURTHER
AWAY AND UPPER HEIGHTS BEGIN TO RISE. SUNSHINE AND WEAK RETURN
FLOW WILL HELP BOOST HIGHS BACK INTO THE 60S.
LONG TERM...SUNDAY THROUGH WEDNESDAY
EXTENDED FORECAST CONTINUES TO TREND WARMER...AS 12Z 17 OCT MODELS
ADVERTISE UPPER TROUGH DEVELOPING ACROSS THE WESTERN CONUS AND
RIDGE BUILDING DOWNSTREAM OVER THE MIDWEST/OHIO RIVER VALLEY.
ECMWF REMAINS THE MOST AMPLIFIED MODEL...KEEPING UPPER HEIGHTS
QUITE HIGH ACROSS THE REGION THROUGH THE MIDDLE OF NEXT WEEK.
THE GFS...WHICH HAD PREVIOUSLY BEEN LESS AMPLIFIED WITH THE
TROUGH/RIDGE PATTERN...IS NOW BEGINNING TO LOOK MORE LIKE THE
ECMWF. THE MAIN QUESTION IN THE EXTENDED WILL BE WHERE THE
PREVAILING BAROCLINIC ZONE SETS UP BETWEEN A COOLER AIRMASS TO THE
NORTHWEST AND WARMER AIR TO THE SOUTHEAST. RECENT FORECASTS HAVE
TRENDED TOWARD THE ECMWF...WHICH KEEPS THE FRONT STALLED ACROSS
NORTHERN SECTIONS OF IOWA/ILLINOIS EARLY NEXT WEEK. LATEST RUN OF
THE ECMWF SHOWS GOOD CONSISTENCY FROM PREVIOUS SOLUTION...WHILE
GFS IS BEGINNING TO TREND NORTHWARD WITH THE FRONT AS WELL. AS A
RESULT...HAVE WARMED TEMPS MONDAY THROUGH WEDNESDAY TO FEATURE
DAILY HIGHS IN THE 70S. HAVE ALSO TRIMMED POPS...WITH ONLY LOW
CHANCE POPS MENTIONED ACROSS THE NORTHWEST CWA MONDAY INTO
TUESDAY. IF ECMWF PANS OUT...POPS MAY EVENTUALLY NEED TO BE
REMOVED ALTOGETHER AND TEMPS MAY NEED TO BE ADJUSTED UPWARD EVEN
FURTHER.
&&
.AVIATION...
ISSUED 650 PM CDT WED OCT 17 2012
IFR TO MVFR CEILINGS AND VSBYS EXPECTED WITH A BAND OF SHOWERS AND
A FEW EMBEDDED THUNDERSTORMS AT PIA AND SPI AHEAD OF A COLD FRONT
IN WESTERN IL RACING EAST INTO EASTERN IL THIS EVENING...REACHING
BMI AND DEC BY 01Z AND CMI BY 02Z. ALSO HAVE SCATTERED SHOWERS AND
A FEW THUNDERSTORM AHEAD OF THIS BAND OVER EASTERN IL MAINLY FROM
DEC AND CMI EAST SO INCLUDED NEXT FEW HOURS THERE AS WELL. BREEZY
SOUTH WINDS TO TURN WEST BEHIND THE LINE OF SHOWERS AND
THUNDERSTORMS DURING THIS EVENING AND HAS ALREADY OCCURRED AT SPI
WITH WEST WIND GUST OF 34 KTS. USED HRRR MODEL END CONVECTION FROM
WEST TO EAST BETWEEN 03Z- 06Z THEN SCATTERING OUT LOW CLOUDS EARLY
OVERNIGHT FROM WEST TO EAST A FEW HOURS AFTER RAIN ENDS. STRONG
537 DM 500 MB LOW ALONG THE EASTERN DAKOTAS BORDER TO DEEPEN TO
532 DM BY 00Z/7 PM THU NEAR DUBUQUE. THIS TO SPREAD BROKEN CLOUDS
3-5KT SE ACROSS CENTRAL IL DURING MID/LATE THU AFTERNOON. STRONG
SW WINDS 15-20 KTS WITH GUSTS OF 25-30 KTS EXPECTED THU DUE TO
TIGHT PRESSURE GRADIENT WITH 995 MB LOW PRESSURE OVER THE UPPER MS
VALLEY.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
647 PM CDT WED OCT 17 2012
.AVIATION...
THE RAIN HAS ALREADY CLEAR CID...AND SHOULD QUICKLY EXIT BRL BY
01Z...FOLLOWED BY MLI AND DBQ AROUND 0130 TO 02Z/18. UNTIL THE
RAIN ENDS...MVFR CONDITIONS WITH DIPS INTO IFR ARE
LIKELY...CONDITIONS AS LOW AS 1 MILE VIS AND 800 FT CIGS ARE
POSSIBLE. WEST WINDS WILL BLOW AT 12 WITH GUSTS TO 24KTS THROUGH
THE END OF THE RAIN EVENT. AFTER RAIN ENDS...WEST WINDS...AND VFR
CONDITIONS SHOULD LAST THROUGH THE PERIOD. WINDS AROUND 10 KTS
OVERNIGHT WITH CIGS OF 5000 TO 10000 FT WILL INCREASE TO 14KTS
GUSTING TO 24KTS AFTER 15Z/18. SCATTERED SHOWERS SHOULD BEGIN TO
AFFECT ALL SITES AFTER 15Z...AS AN UPPER LEVEL LOW PRESSURE SYSTEM
ROTATES OVER THE REGION. SHOWERS SHOULD CONTINUE THROUGH THE NEXT
36 HOURS...BUT SHOULD GENERALLY BE LIGHT AND CONDITIONS MAINLY
VFR.
ERVIN
&&
.PREV DISCUSSION... /ISSUED 417 PM CDT WED OCT 17 2012/
UPDATE...
UPDATED POPS AND WEATHER TO REFLECT THE CURRENT RADAR POSITION OF
WIDESPREAD SHOWERS FOR THIS AFTERNOON AND EARLY EVENING.
ERVIN
SYNOPSIS...
12Z UA ANALYSIS HAS 850MB LOWS ON THE NORTH SHORE OF LAKE WINNIPEG
AND IN NORTHWEST MINNESOTA. AN 850MB COLD FRONT RAN FROM THE
MINNESOTA LOW INTO SOUTHEAST NEW MEXICO WITH A TROF FROM SOUTHERN
MINNESOTA INTO SOUTH TEXAS. SATELLITE/RADAR TRENDS SHOWS EXTENSIVE
LOW AND MID LEVEL CLOUDS WITH STRONG CONVECTION ACROSS MISSOURI
AND MORE SCATTERED CONVECTION ACROSS IOWA/ILLINOIS.
18Z SFC ANALYSIS HAS A LOW EAST OF KFAR WITH THE COLD FRONT SOUTH
INTO SOUTHEAST KANSAS. TWO MESO LOWS WERE IN SOUTHWEST MISSOURI
AND NORTHEAST OKLAHOMA. A PRE-FRONTAL TROF RAN FROM JUST EAST OF
KMSP TO ABOUT KIRK. DEW POINTS AHEAD OF THE COLD FRONT WERE IN THE
50S AND 60S WITH 20S AND 30S BEHIND THE COLD FRONT IN THE PLAINS.
SHORT TERM...TONIGHT AND THURSDAY
THE CURRENT PICTURE AT MID AFTERNOON HAS MID LEVEL FORCING OR A
WEAK VORT MAX PUSHING A SLUG OF MAINLY SHRA ACROSS THE CWFA. A
MUCH STRONGER VORT MAX IS ROTATING NORTHEAST ACROSS MISSOURI. IF
THE TRENDS OF THE RAP ARE CORRECT...THERE SHOULD BE A BAND OF
ENHANCED CONVECTION THAT DEVELOPS LATE THIS AFTERNOON IN THE
SOUTHEAST QUADRANT OF THE CWFA AND ROTATES NORTHEAST.
THIS BAND OF CONVECTION WILL BE ACROSS ROUGHLY THE EASTERN 40
PERCENT OF THE CWFA DURING THE EARLY EVENING HOURS BEFORE EXITING
THE CWFA. SOME LINGERING SHRA SHOULD THEN BE SEEN IN THE THE MID
AND LATE EVENING HOURS BEFORE ENDING.
AFTER MIDNIGHT THERE SHOULD BE SOME CLEARING OF THE CLOUDS WITH
DRY CONDITIONS AS CONDENSATION PRESSURE DEFICITS RISE
CONSIDERABLY. CONDENSATION PRESSURE DEFICITS IN THE 850-700MB
LAYER COLLAPSE AGAIN ACROSS THE CWFA PRIOR TO SUNRISE BUT THE
1000-850MB LAYER CONDENSATION PRESSURE DEFICITS ONLY LOWER
SLIGHTLY. THUS MOST OF THE AREA SHOULD REMAIN DRY AFTER MIDNIGHT
BUT SOME SPRINKLES MIGHT ENTER THE FAR NORTHWEST PART OF THE CWFA
JUST PRIOR TO DAWN.
THURSDAY...WRAP AROUND CLOUDS/PRECIP MOVE SOUTHEAST THROUGH THE
CWFA DURING THE MORNING HOURS. STEEP LAPSE RATES WILL AID IN
DEVELOPING NEW DIURNAL CLOUDS IN AREAS THAT WERE PARTIALLY CLEAR
AT SUNRISE. SCATTERED SHRA WILL BECOME MORE NUMEROUS DURING THE
DAY AS A VORT MAX ROTATES THROUGH AND INCREASES THE LIFT. THE
FREEZING LEVEL IS 3.0-3.5 KFT AGL PLUS/MINUS 700 FT DEPENDING ON
LOCAL ELEVATION ABOVE SEA LEVEL. HOWEVER...THE LOWEST 2 KFT ABOVE
THE GROUND REMAINS ABOVE FREEZING. THUS IN THE STRONGER SHOWERS
THE POTENTIAL DOES EXIST FOR SOME SMALL GRAUPEL TO DEVELOP THAT
REACHES THE GROUND.
TEMPERATURES WILL REMAIN IN THE 40S FOR MUCH OF THE DAY BUT THE
SOUTHEAST THIRD TO 40 PERCENT OF THE CWFA MAY MANAGE TO GET INTO
THE LOWER 50S. REGARDLESS...IT WILL BE A COLD RAW DAY WHEN THE
WIND IS FACTORED IN. 08
LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
UPPER LOW PROGGED TO EXIT INTO THE GREAT LAKES REGION BY FRI NGT.
UNTIL THEN WILL SEE CONSIDERABLE CLOUDINESS ALONG WITH BOUTS OF
LIGHT RAIN OR SHOWERS... AS SPOKES OF ENERGY ROTATE DOWN THE
BACKSIDE OF THE LOW. CLOUDS WILL ACT AS BLANKET AND LIMIT DIURNAL
SWINGS INTO FRI. CLOUD FORECAST CHALLENGING FRI NGT INTO SAT WITH
OVERALL INCOMING SUBSIDENCE IN WAKE OF DEPARTING LOW SUPPORTIVE OF
CLEARING... BUT NAM BUFR SOUNDINGS DEPICT A LOT OF LOW LEVEL
MOISTURE TRAPPED BENEATH SUBSIDENCE INVERSION. TIME OF YEAR WITH
LOWER SUN ANGLE BECOMING MORE FAVORABLE FOR THESE SCENARIOS AND
NUDGED TOWARD A MORE PESSIMISTIC SKY COVER FRI NGT THUS STAYING AT
OR ABOVE WARM SIDE OF GUIDANCE ON LOWS.
SAT-SUN... DRY WITH WARMING TREND TO ABOVE NORMAL TEMPS BY SUN AS
NEXT SIGNIFICANT TROUGH PUSHES INTO THE PACIFIC NORTHWEST... WHICH
RESULTS IN DOWNSTREAM AMPLIFICATION OF UPPER RIDGE OVER THE REGION.
MON-WED... ABOVE NORMAL TEMPS GENERALLY SUGGESTED WITH DEEP TROUGHING
OVER THE WESTERN CONUS AND SW FLOW ALOFT. SW FLOW COUPLED WITH FRONTAL
ZONE WAVERING NEARBY WILL RESULT IN OCCASIONAL RAIN CHCS AS WELL
DURING THE PERIOD. THE FIRST RAIN CHCS APPEAR TO ARRIVE AS EARLY AS
MONDAY MORNING WITH MORE ROBUST LOW LEVEL WARM ADVECTION REGIME.
OTHERWISE... IT IS DIFFICULT TO PIN DOWN RAIN CHCS THEREAFTER WITH
MODELS OFFERING DIFFERENCES ON LOCATION OF THE FRONT AND TIMING OF
UPPER LEVEL DISTURBANCES EJECTING FROM WESTERN TROUGH.
TRANSITION TO SIGNIFICANTLY COLDER REGIME IS DEPICTED BY ECMWF AND GFS
BY THE END OF NEXT WEEK INTO NEXT WEEKEND. 05
AVIATION... /ISSUED 1247 PM CDT WED OCT 17 2012/
A COLD FRONT WILL SWEEP THROUGH EASTERN IOWA AND ILLINOIS IN THE
18Z/17 TO 00Z/18 TIME FRAME. VFR WX IS GENERALLY EXPECTED WITH
SPRINKLES OR SHRA. ALONG/EAST OF THE MISSISSIPPI RIVER ISOLD TSRA
WILL BE POSSIBLE THAT ARE EXPECTED TO BECOME MORE NUMEROUS AFT
21Z. VFR CONDITIONS ARE EXPECTED BUT THERE MAY BE BRIEF INCURSIONS
OF MVFR CONDITIONS WITH ANY TSRA OR STRONGER SHRA. AFT 00Z/18 VFR
CONDITIONS ARE EXPECTED. CIGS WILL LOWER AGAIN AFT 12Z/18 BUT
SHOULD REMAIN VFR. 08
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
509 PM EDT TUE OCT 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT AND REMAIN ACROSS
THE REGION WEDNESDAY INTO WEDNESDAY NIGHT. THE HIGH WILL MOVE EAST
OF THE STATE ON THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
UPDATE: QUICK UPDATE TO ADJUST THE TEMPERATURES/DEWPOINTS DOWN AS
COLDER AIR MOVING SE FROM CANADA. ADJUSTED THE POPS AS WELL TO
ACCOUNT FOR THE RADAR WHICH SHOWED THE BULK OF RAIN NOW INTO NEW
BRUNSWICK AND ANOTHER SMALLER AREA MOVING ACROSS NE AROOSTOOK
COUNTY. THE LATEST RUC HAD THIS HANDLED NICELY.
PREVIOUS DISCUSSION...
THE LOW WHICH BROUGHT RAIN TO THE AREA MUCH OF THE DAY WILL
QUICKLY LIFT NORTHEAST AND AWAY TONIGHT AS HIGH PRESSURE BUILDS
OVER THE STATE. THIS WILL ALLOW CLEARING THROUGHOUT THE REGION
TONIGHT AND TEMPS WILL DROP TO NEAR OR JUST BELOW FREEZING IN MOST
AREAS. HIGH PRESSURE WILL REMAIN OVER THE REGION WEDNESDAY
BRINGING SUNSHINE WITH AFTERNOON TEMPS RANGING FROM THE UPPER 50S
DOWNEAST TO THE LOW 50S OVER THE NORTH. WINDS WILL BE VERY LIGHT
AS THE HIGH CRESTS OVER THE REGION.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
NORTHERN NEW ENGLAND WILL BEGIN THIS FORECAST PERIOD UNDERNEATH AN
UPPER RIDGE. THIS WILL ALLOW FOR ABOVE NORMAL TEMPERATURES AND
DRY WEATHER. HIGH CLOUDS WILL SPILL OVER THE RIDGE AXIS FOR MOSTLY
CLOUDY SKIES. WILL HAVE TO WATCH OUT FOR LOW CLOUDS AND FOG ALONG
THE COASTAL ZONES LATE THURSDAY NIGHT AND EARLY FRIDAY MORNING DUE
TO A STRONG ONSHORE FLOW.
WINDS WILL INCREASE ON FRIDAY AS AN OCCLUDED FRONT APPROACHES FROM
THE WEST. EXPECT RAIN OR RAIN SHOWERS TO DEVELOP DURING THE DAY
ACROSS NORTHERN AND DOWNEAST MAINE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AN OCCLUDED FRONT WILL CROSS THE REGION FRIDAY NIGHT THROUGH
SATURDAY NIGHT...THOUGH UNCERTAINTY STILL EXISTS REGARDING HOW
QUICKLY THE FRONT MOVES EAST OF THE REGION LATER SATURDAY THROUGH
SATURDAY NIGHT. AN AREA OF RAIN WILL CROSS THE REGION IN ADVANCE
OF THE OCCLUSION FRIDAY NIGHT INTO SATURDAY...THEN TAPER TO
SHOWERS IN THE WAKE OF THE FRONT LATER SATURDAY INTO SATURDAY
NIGHT DEPENDENT ON THE TIMING OF THE FRONT. SHOWERS WRAPPING
AROUND THE EXITING SYSTEM COULD BRING A CHANCE OF SHOWERS TO THE
NORTH/MOUNTAINS SUNDAY...WITH PARTLY CLOUDY SKIES DOWNEAST. HIGH
PRESSURE SHOULD THEN BUILD ACROSS THE REGION MONDAY. A COLD FRONT
COULD THEN BRING A CHANCE OF SHOWERS TUESDAY. TEMPERATURES SHOULD
BE AT SLIGHTLY ABOVE NORMAL LEVELS SATURDAY THROUGH MONDAY...WITH
NEAR NORMAL LEVEL TEMPERATURES TUESDAY.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: CONDITIONS WILL IMPROVE TO VFR TONIGHT THEN REMAIN VFR
IN MOSTLY CLEAR SKIES ON WEDNESDAY.
SHORT TERM: MVFR CIGS AND VSBYS ARE POSSIBLE AT KBHB AND KBGR LATE
THURSDAY NIGHT AND EARLY FRIDAY MORNING DUE TO LOW CLOUDS AND FOG.
MVFR CIGS AND VSBYS ARE POSSIBLE FRIDAY AFTERNOON AT ALL TAF SITES
DUE TO LOW CLOUDS AND SHOWERS AS AN OCCLUDED FRONT MOVES INTO THE
REGION. MVFR/IFR CONDITIONS ARE EXPECTED ACROSS THE REGION FRIDAY
NIGHT INTO EARLY SATURDAY NIGHT...WITH MVFR CONDITIONS LATER
SATURDAY NIGHT. OCCASIONAL MVFR CONDITIONS COULD LINGER ACROSS
THE NORTH/MOUNTAINS SUNDAY...WITH VFR CONDITIONS DOWNEAST.
&&
.MARINE...
NEAR TERM: AN SCA WILL CONTINUE TONIGHT FOR NORTHWEST WINDS
GUSTING UP TO 25 KT. WINDS WILL DIMINISH LATE TONIGHT AND THEN BE
LIGHT ON WEDNESDAY AS THE HIGH CRESTS OVER THE WATERS.
SHORT TERM: SCA CONDITIONS ARE LIKELY THURSDAY WITH WAVE HEIGHTS IN
THE 4 TO 7 FOOT RANGE AND FRIDAY WITH WAVE HEIGHTS IN THE 6 TO 9
FOOT RANGE AND WIND GUSTS IN EXCESS OF 25 KNOTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...BLOOMER/HEWITT
SHORT TERM...OKULSKI
LONG TERM...NORCROSS
AVIATION...BLOOMER/HEWITT
MARINE...BLOOMER/HEWITT/OKULSKI
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
732 PM EDT WED OCT 17 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 432 PM EDT WED OCT 17 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF IN THE PROCESS OF
AMPLIFYING OVER THE PLAINS. THERE ARE A NUMBER OF EMBEDDED SHORTWAVES
IN THE DEEPENING TROF...BUT THE 130-140KT JET PER LATEST RUC
CURRENTLY DROPPING DOWN THE BACKSIDE OF THE TROF WILL BE THE FACTOR
LEADING TO THE TROF CONTINUING TO DEEPEN. IN FACT...TROF WILL BECOME
DEEP FOR THIS TIME OF YEAR. AT PEAK INTENSITY THU OVER THE
MID/UPPER MISSISSIPPI VALLEY...500MB HEIGHTS WILL BE 3.5 STANDARD
DEVIATIONS BLO THE LONG TERM AVG FOR MID OCT. AT THE SFC...LOW PRES
OF 29.1 INCHES IS OVER NW MN WITH COLD FRONT EXTENDING INTO FAR WRN
WI/FAR ERN IA AND MO. SO FAR...PCPN COVERAGE HAS BEEN GREATEST NEAR
THE SFC LOW OVER NW MN/ERN ND. HOWEVER...SHRA ARE INCREASING IN
COVERAGE SOUTHWARD ALONG/AHEAD OF COLD FRONT AS UPPER DIFFLUENCE
IMPROVES DUE TO AFOREMENTIONED UPPER JET DROPPING DOWN BACKSIDE OF
THE TROF.
AS TROF CONTINUES TO DEEPEN TONIGHT...A NEW LOW PRES CENTER IS
EXPECTED TO DEVELOP ON COLD FRONT IN ERN WI AND THEN LIFT NW TO THE
VCNTY OF WRN LAKE SUPERIOR THU MORNING. DEEPENING SYSTEM WILL LEAD
TO LOW-LEVEL JET RAMPING UP TO AROUND 50KT WHICH WILL TRANSPORT
ABUNDANT MOISTURE N INTO THE AREA (PRECIPITABLE WATER INCREASES TO
200PCT OF NORMAL OR BETTER). STRONG DIRECTIONAL DIFFLUENCE AT UPPER
LEVELS OVERTOP TIGHTENING LOW LEVEL FRONTAL BOUNDARY WILL SUPPORT AN
EXPANDING AREA OF SHRA SPREADING INTO THE FCST AREA TONIGHT. LIKELY
TO CATEGORICAL POPS LOOK ON TRACK. MODELS HAVE AND CONTINUE TO POINT
TOWARD SW/W UPPER MI RECEIVING THE HEAVIEST RAINFALL WITH THAT AREA
NEAR THE TRACK OF NW MOVING SFC WAVE. SO...AS IN PREVIOUS FCSTS...
HIGHEST POPS WERE PAINTED IN THAT AREA. NOT OUT OF THE QUESTION THAT
THERE MAY BE A FEW RUMBLES OF THUNDER GIVEN SHOWALTER INDEX FALLING
TOWARD ZERO. MIN TEMPS WILL BE WELL ABOVE NORMAL GIVEN CLOUDS/DEEP
MOISTURE. MINS SHOULD RANGE FROM THE MID 40S FAR W WHERE CAA WILL
GET UNDERWAY OVERNIGHT TO THE MID 50S EAST.
MAIN PUSH OF PCPN FROM TONIGHT WILL ROTATE NW OF THE AREA BY
MORNING. SO THERE MAY BE SOMEWHAT OF A BREAK IN PCPN FOR A WHILE THU
MORNING. HOWEVER...A SHORTWAVE ROTATING AROUND MIDLEVEL LOW WILL BE
SWINGING N TOWARD ERN UPPER MI...AND SHOULD BRING ANOTHER ROUND OF
GREATER SHRA COVERAGE INTO ESPECIALLY THE CNTRL AND ERN FCST AREA
FOR THE AFTN. TEMP RISE THU WILL BE LIMITED BY CLOUDS/CAA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT WED OCT 17 2012
AN UPPER LOW WILL BE SPINNING OVER FAR SW WI AT 00Z FRI...WITH A SFC
LOW TO THE N OF IT BUT S OF WRN LAKE SUPERIOR. A SHORTWAVE TROUGH
WILL BE JUST SE OF THE CWA AT 00Z FRI...MOVING E TO W TO NEAR THE
CENTER OF THE CWA BY 06Z FRI...THEN TO FAR WRN UPPER MI/FAR WRN LAKE
SUPERIOR BY 12Z FRI. MODELS ARE IN GOOD AGREEMENT WITH THE
SHORTWAVE...WITH ONLY MINOR TIMING DIFFERENCES BETWEEN THEM /THE GFS
WAS USED WITH THE HIGHEST WEIGHT SINCE THE TIMING WAS BETWEEN THE
FASTER NAM AND SLOWER ECMWF/. THE BEST CHANCES FOR WIDESPREAD PRECIP
WILL BE FROM 00Z-06Z FRI. AFTER 06Z FRI...THE SFC LOW MOVING THROUGH
WITH THE SHORTWAVE WILL QUICKLY MOVE TO SW WI. ALSO...BETWEEN
00Z-12Z FRI...THE MID/UPPER LOWS WILL BE STACKED JUST W OF LAKE
MICHIGAN...WITH LOW LEVEL CYCLONIC FLOW UP THE LONG AXIS OF LAKE
MICHIGAN. 850MB TEMPS WILL BE BETWEEN 0C AND -1C...SO LAKE ENHANCED
RAIN WILL BE POSSIBLE INTO SCENTRAL AND ERN UPPER MI LATE THU NIGHT
INTO FRI MORNING.
SFC FEATURES BEGIN TO BREAK DOWN QUICKLY ON FRI AS THE SYSTEM MOVES
TO SE LOWER MI BY LATE IN THE DAY. THE ECMWF IS ABOUT 12 HOURS
SLOWER IN MOVING THE SYSTEM INTO QUEBEC ON SAT. EVEN SO...MODELS
AGREE WITH SHOWING A SFC RIDGE MOVING INTO THE CWA AROUND 18Z
SAT...WITH AN UPPER RIDGE PUSHING IN FROM THE NW. THE RIDGE WILL
LEAD TO PRETTY QUIET WEATHER OVER THE WEEKEND...WITH ANY SIGNIFICANT
CHANCES FOR RAIN BEING OVER THE FAR E AS THE LOW MOVES E OF THE CWA
SAT...BUT THOSE CHANCES ARE SMALL. SINCE WARM AIR WILL NOT START TO
RETURN TO THE AREA UNTIL THE SFC RIDGE MOVES THROUGH...SAT WILL SEE
SIMILAR TEMPS TO FRI WITH HIGHS IN THE MID 40S TO MID 50S. SUN WILL
BE WARMER AS 850MB TEMPS INCREASE TO 8-10C...LEADING TO HIGHS IN THE
50S AND 60S.
AFTER SUN...SUBSTANTIAL MODEL DISAGREEMENT ON THE LOCATION OF A SFC
RIDGE THAT MAY MOVE IN THE REGION. THE PROBLEM COMES FROM A SFC
TROUGH/STATIONARY FRONT THAT WILL BE S OF THE RIDGE. THE GFS KEEPS
THE RIDGE OVER THE CWA THROUGH NEXT WED...KEEPING US DRY...BUT THE
ECMWF HAS THE TROUGH/FRONT OVER THE CWA THROUGH MUCH OF THE
PERIOD...WHICH WOULD RESULT IN A MOST WET FORECAST. WITH HIGH MODEL
DISAGREEMENT AND LOW RUN TO RUN CONTINUITY...USED A CONSENSUS OF
MODELS IN THIS PORTION OF THE FORECAST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 730 PM EDT WED OCT 17 2012
EXPECT PREDOMINANT VFR CONDITIONS TO DETERIORATE TO IFR TNGT AS LO
PRES DEVELOPING TO THE S MOVES N THAN NW NEAR THE WI BORDER AND
BRINGS ALONG SHRA/LLVL MSTR. THERE WL ALSO BE A GUSTY ESE WIND AT
CMX/SAW UNDER THE SHARPER PRES GRADIENT ON THE NE FLANK OF THE LO
CENTER. ALTHOUGH THE STEADY RA WL DIMINISH LATE TNGT ONCE THE LO
SHIFTS FARTHER TO THE W...LINGERING LLVL MSTR/CYC FLOW WL SUPPORT
CONTINUED IFR/MVFR CONDITIONS THRU THE REST OF THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT WED OCT 17 2012
A TRICKY FCST SHAPING UP TONIGHT INTO THU. DEEP SFC LOW NOW IN NW MN
WILL BE REPLACED BY A NEW LOW PRES WAVE THAT WILL DEVELOP IN ERN WI
TONIGHT AND THEN ROTATE NW TO VCNTY OF WRN LAKE SUPERIOR THU. IN
RESPONSE TO THE NEW LOW...A BRIEF PERIOD OF E TO SE GALES MAY
DEVELOP LATE TONIGHT INTO THU MORNING OVER CNTRL AND ERN LAKE
SUPERIOR. GIVEN UNCERTAINTY IN HOW QUICK OR DEEP THE NEW LOW WILL
BECOME BY THU MORNING...HELD OFF ON THE ISSUANCE OF A GALE WARNING
FOR NOW. AS A TROUGH MOVES THROUGH THURSDAY NIGHT...SOUTHEAST WINDS OVER
EASTERN LAKE SUPERIOR AND NORTHEAST WINDS OVER WESTERN LAKE SUPERIOR
WILL GUST TO AROUND 25KTS. WINDS WILL THEN DIMINISH TO BELOW 20KTS
FRIDAY THROUGH MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...KC
MARINE...ROLFSON/TITUS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
657 PM EDT TUE OCT 16 2012
.SYNOPSIS...
ISSUED AT 345 PM EDT TUE OCT 16 2012
A WARM FRONT WILL LIFT NORTH THROUGH MICHIGAN TONIGHT AND MAY TOUCH
OFF A FEW SHOWERS AND THUNDERSTORMS. IN THE WAKE OF THIS WARM
FRONT... WEDNESDAY WILL BE THE WARMEST DAY OF THE WEEK AS
TEMPERATURES RISE TO NEAR 70. THE WARM UP WILL BE SHORT LIVED
HOWEVER BECAUSE ANOTHER COLD FRONT WILL SWEEP THROUGH THE REGION ON
WEDNESDAY NIGHT AND BRING A WIDESPREAD AREA OF RAIN WITH IT.
COOLER AND SHOWERY WEATHER CAN BE EXPECTED FOR THURSDAY AND FRIDAY
AS A LOW PRESSURE SYSTEM OVER ALBERTA CANADA MOVES SOUTHEAST AND
STALLS OVER THE GREAT LAKES REGION. THAT SYSTEM SHOULD PUSH OUT OF
THE REGION EARLY SATURDAY LEADING TO A PREDOMINATELY DRY PATTERN FOR
THE COMING WEEKEND WITH MODERATING TEMPERATURES.
&&
.UPDATE...
ISSUED AT 657 PM EDT TUE OCT 16 2012
I UPDATED THE GRIDS TO HAVE LIKELY POP ALONG THE ROUTE 10
CORRIDOR THIS EVENING INTO EARLY TONIGHT . THIS IS TO REFLECT THE
CURRENT AREA OF SHOWERS STRENGTHENING THIS EVENING AS IT MOVES
ACROSS THE AREA ( MOSTLY NORTH OF I-96).
AN AREA OF SHOWERS CONTINUES TO DEVELOP AND MOVE EAST NORTHEAST
ACROSS CENTRAL LAKE MICHIGAN (MOSTLY N OF MKE TO MKG LINE) EARLY
THIS EVENING. THIS IS ON THE NOSE A STRENGTHENING LOW LEVEL JET
(40-45 KNOT CORE EAST OF THE QUAD CITIES AT 21Z). THIS AREA WILL
LIKELY INTENSIFY THIS EVENING AS THE LOW LEVEL JET STRENGTHENS
AFTER DARK. WITH THE CORE OF THE JET CROSSING THE GRR AREA AROUND
MIDNIGHT...I WOULD EXPECT MOST OF THE ACTIVITY TO BE NORTH OF
INTERSTATE 96. WITH A DRY SUB CLOUD LAYER SEEN ON THE RAP AND LAPS
SOUNDINGS THIS EVENING... I WOULD EXPECT GUSTY WINDS OUT OF ANY
SHOWER THAT MOVES ACROSS THE AREA UNTIL THE BOUNDARY LAYER EITHER
MOISTENS OR A STRONGER RADIATION INVERSION DEVELOPS. MOST OF THIS
ACTIVITY WILL BE EAST OF THE CWA AFTER 02Z (SHORTWAVE IS EAST OF
THE AREA).
THE INSTABILITY IS MOSTLY AT MID LEVELS AND THE STRONGEST LIFT
NORTH OF MKG IS NEAR THE -20C ISOTHERM AND THAT AREA IS FORECAST
TO BE SATURATED THIS EVENING. SO I WOULD THING THERE SHOULD BE
SOME ISOLATED THUNDERSTORMS WITH THIS AREA SHOWERS TOO.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 345 PM EDT TUE OCT 16 2012
PLUME OF ELEVATED INSTABILITY WITH MID LEVEL LAPSE RATES OF 8-8.5
C/KM OVER IOWA THIS AFTERNOON WILL BE SHIFTING TOWARD SW LWR MI THIS
EVENING... AIDED BY A 45 KT SWLY H8 JET. THAT LOW LEVEL JET IS IN
ADVANCE OF AN H5 SHORTWAVE OVER MN/IA THAT WILL BE PROGRESSING EAST
TOWARD MI. THESE INGREDIENTS SUPPORT A CHANCE OF SHOWERS AND TSTMS
TONIGHT... BUT MOISTURE IS A LIMITING FACTOR WHICH SHOULD LIMIT
COVERAGE. SUSPECT WE WILL BEGIN SEEING SOME HIGHER BASED ACCAS
CLOUDS MOVING IN TOWARD/AFTER SUNSET.
LOOKS LIKE THERE WILL BE A LULL IN PCPN POTENTIAL WEDNESDAY MORNING
INTO THE EARLY AFTERNOON AS THE AFOREMENTIONED SHORTWAVE MOVES OUT
AND THE NEXT WAVE DIVES INTO THE BASE OF THE DIGGING LONGWAVE TROUGH
TO OUR WEST. IT IS THIS WAVE WHICH BRINGS A CATEGORICAL CHANCE FOR
RAIN SHOWERS WEDNESDAY NIGHT. MODELS ARE IN DECENT AGREEMENT ON
TIMING OF THIS FEATURE AND ASSOCIATED SFC FRONT/OCCLUSION PIVOTING
NE THROUGH THE REGION AND PROVIDING A WIDESPREAD SOAKING RAIN.
WHILE RAIN SHOWERS SHOULD END FOR A TIME THURSDAY WITH THE PASSAGE
OF THE COLD FRONT/OCCLUSION... MORE SCATTERED SHOWERS WILL PROBABLY
DEVELOP IN THE AFTERNOON AS THE UPPER LOW AND COLD POOL ALOFT MOVE
IN.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 345 PM EDT TUE OCT 16 2012
RAIN SHOWERS LIKELY TO LINGER FRIDAY BEFORE MOVING OFF FRIDAY NIGHT
AS AN UPPER LOW PROGRESSES TO THE EAST/NORTHEAST. A WEAK RIDGE OF
HIGH PRESSURE WILL MOVE IN FOR THE WEEKEND...WHICH SHOULD KEEP US
MOSTLY DRY SATURDAY THROUGH THE DAY ON MONDAY. AS THE RIDGE OF HIGH
PRESSURE MOVES OFF LATE MONDAY...A MOIST SOUTHWEST FLOW ALOFT WILL
BRING THE POTENTIAL FOR SHOWERS AND MAYBE THUNDERSTORMS LATE MONDAY
NIGHT THROUGH TUESDAY NIGHT.
TEMPERATURES WILL ONLY CLIMB TO AROUND 50 DEGREES ON FRIDAY WITH THE
LINGERING RAIN. GRADUAL WARM UP THROUGH THE WEEKEND...WITH LOWER TO
MID 60S POSSIBLE SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 657 PM EDT TUE OCT 16 2012
FOR THE MOST PART VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF
PERIOD. WITH THE SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED
WITH THE SHORTWAVE CROSSING CENTRAL LOWER MICHIGAN THIS EVENING
COULD BE BRIEF MVFR VSBY IN HEAVIER SHOWERS. ALSO EXPECT GUSTY
WINDS NEAR SHOWERS AS THERE IS A SIGNIFICANT DRY SUB-CLOUD LAYER.
THIS AREA OF CONVECTION SHOULD BE EAST OF THE TAF SITES BY 06Z OR
SO. THEN PARTLY CLOUD SKIES WITH LAYERED MID CLOUDS SHOULD PREVAIL.
THE NEXT AREA OF RAIN ASSOCIATED WITH THE PRIMARY STORM SYSTEM TO
OUR WEST WILL MOVE IN AFTER 00Z THURSDAY. I EXPECT IFR CIGS/VSBY
AS THAT MOVES THROUGH.
&&
.MARINE...
ISSUED AT 345 PM EDT TUE OCT 16 2012
SMALL CRAFT ADVISORIES CONTINUE AS SOUTHERLY LOW LEVEL JET IMPACTS
LK MI. ADDED WATERSPOUTS TO THE FCST BEHIND THE COLD FRONT THURSDAY
AS UPPER COLD POOL MOVES OVERHEAD.
&&
.HYDROLOGY...
ISSUED AT 345 PM EDT TUE OCT 16 2012
THE BAND OF RAIN ON WEDNESDAY NIGHT COULD PRODUCE WIDESPREAD AMOUNTS
OF 0.50 TO 1.0 INCHES. HOWEVER THIS SHOULD HAVE LITTLE IMPACT ON THE
RIVERS WHICH ARE STILL RUNNING LOW EVEN AFTER LAST WEEKEND/S 1.5 TO
3 INCH RAIN EVENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...JMM
AVIATION...WDM
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
435 PM EDT TUE OCT 16 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 431 PM EDT TUE OCT 16 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW ALF
OVER THE UPR LKS. SHRTWV EMBEDDED WITHIN THIS FLOW IS MOVING THRU
ONTARIO/MN. COMBINATION OF ISENTROPIC ASCENT BEST DEPICTED ON THE
295-300K SFCS/H7 MSTR CNVGC AND UPR DVGC IN RRQ OF 80KT H3 JET MAX
MOVING THRU SE CANADA IS CAUSING AN AREA OF SHRA OVER THE UPR LKS
THIS AFTN. THE PCPN IS MOST WIDESPREAD OVER THE N AND CNTRL CWA...
WITH DRIER AIR BLO H75 DEPICTED ON THE 12Z GRB RAOB AND MORE
IMPRESSIVE ISENTROPIC ASCENT TO THE N RESTRICTING PCPN COVERAGE OVER
THE SCNTRL. TO THE W...DNVA/MID LVL DRYING/LARGER SCALE QVECTOR DVGC
IN THE WAKE OF THE SHRTWV ARE BRINGING A DRYING TREND IN MN...WITH
THE BACK EDGE OF THE RA AREA PUSHING THRU WRN LK SUP EARLY THIS
AFTN. SKIES ARE MOCLR OVER THE NRN PLAINS INTO MN UNDER THE RDG
TRAILING THE SHRTWV. ANOTHER POTENT SHRTWV EMBEDDED IN THE ZONAL
FLOW ALF IS PUSHING INTO THE NRN ROCKIES. THERE WERE SOME 00Z-12Z H3
HGT FALLS IN EXCESS OF 200M ASSOCIATED WITH THIS DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND PCPN/CLD TRENDS
THRU THE REST OF THIS AFTN THEN TO POTENTIAL FOR FOG TNGT AS DRIER
AIR ALF OVERSPREADS THE AREA. FOCUS FOR WED TURNS TO PCPN CHCS
ASSOCIATED WITH SHRTWV NOW MOVG THRU THE NRN ROCKIES.
LATE TDAY...BEST H7 MSTR TRANSPORT/UPR DVGC INDICATES THE HEAVIER/
MORE WDSPRD SHRA WL SHIFT INTO THE ERN ZNS WHILE DRYING ALF/LARGER
SCALE QVECTOR DVGC ENDS THE PCPN OVER THE W.
TNGT...EXPECT LINGERING SHRA OVER THE E TO END BY MIDNGT WITH THE
PASSAGE OF THE SHRTWV/ARRIVAL OF DRYING ALF AND DNVA/LARGE SCALE
QVECTOR DVGC. GIVEN THE UPR DRYING/CLD TRENDS...EXPECT CLRG TO
OVERSPREAD THE AREA. WITH LINGERING LLVL MSTR...SUSPECT FOG WL DVLP.
WITH A FAIRLY STEADY SSE WIND...THE BEST CHC FOR MORE WDSPRD/DENSER
FOG AND LO CLDS WL BE OVER THE CNTRL ZNS WHERE THAT FLOW UPSLOPES.
TENDED TOWARD THE LO END OF GUIDANCE FOR MIN TEMPS GIVEN EXPECTED
DRYING ALF...BUT STEADY WIND WL RESTRICT THE FALL FM GOING TOO FAR.
WED...THE AT LEAST THE MRNG SHOULD BE DRY WITH LINGERING DRY AIR/UPR
RDG STILL IN PLACE. BUT STRONG SHRTWV NOW MOVING THRU THE NRN
ROCKIES IS FCST TO CLOSE OFF AND DRIFT INTO FAR NW MN BY 00Z THU. AS
SFC LO MOVES INTO NE MN...ATTENDANT COLD FNT IS PROGGED TO APRCH IWD
LATE IN THE DAY. LOOKS LIKE MOST IMPRESSIVE DPVA/DEEP LYR QVECTOR
CNVGC ASSOCIATED WITH THE SHRTWV WL STAY TO THE NW OF THE AREA WHILE
ANOTHER AREA OF DEEP LYR FORCING/UPR DVGC PASSES WELL TO THE S
CLOSER TO UPR JET AXIS/DEEPER MSTR CNVGC. SO OPTED TO GO NO HIER
THAN CHC POPS OVER THE W HALF OF THE CWA IN THE AFTN...WITH DRY WX
EXPECTED OVER THE E HALF CLOSER TO DEPARTING RDG/DRY AIR. ALTHOUGH
FOG MAY LINGER OVER THE CENTRAL WELL THRU THE MRNG WITH PERSISTENT
UPSLOPE SSE FLOW...RETURN OF MORE SUNSHINE IN THE AFTN WITH H85
TEMPS AS HI AS 10-12C SUG TEMPS WL RISE TO WELL ABV NORMAL. COOLER
CONDITIONS ARE LIKELY OVER THE W WHERE THERE WL BE MORE CLD COVER IN
THE AFTN...BUT SOME MRNG SUNSHINE/DOWNSLOPE S WIND WITH LESS FOG
STILL INDICATE A WARM DAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 431 PM EDT TUE OCT 16 2012
TO BEGIN THE LONG TERM...A DEEP TROF (500MB DEPTH PEAKS THU MORNING
AT 3.5 STANDARD DEVIATIONS FROM THE LONG TERM AVG) WILL BE OVER THE
MID AND UPPER MISSISSIPPI VALLEY. TROF THEN UNRAVELS QUICKLY AND
GETS KICKED NE BY BROAD TROF SETTLING INTO WRN NAMERICA. MEDIUM
RANGE GUIDANCE IS IN POOR AGREEMENT ON THE STRUCTURE/EVOLUTION OF
THE WRN TROF AND STRENGTH/TIMING/TRACKS OF SHORTWAVES EJECTING FROM
TROF. THE GFS RUN-TO-RUN CONSISTENCY FROM LATE WEEKEND INTO EARLY
NEXT WEEK IS IMPROVING WITH LATEST RUNS MORE AGGRESSIVE PUSHING
ENERGY E...FLATTENING DOWNSTREAM RIDGE OVER THE GREAT LAKES/ERN
CONUS AND SHIFTING RIDGE BACK TO THE W. THE ECMWF HAD SHOWN SOMEWHAT
BETTER CONSISTENCY IN DEPICTING A SLOWLY PROGRESSIVE WRN TROF AND A
MORE PRONOUNCED ERN RIDGE THRU EARLY NEXT WEEK. HOWEVER...THE 12Z
ECMWF HAS MADE A BIG SHIFT TOWARD THE GFS IDEA. THRU 12Z MON...THE
GLOBAL GEM/UKMET OFFER OTHER VARYING IDEAS ON THE WRN TROF...BUT
TEND TO LOOK A LITTLE MORE LIKE PREVIOUS ECMWF RUNS. ALL THIS LEADS
TO A VERY LOW CONFIDENCE FCST FOR THE LATTER HALF OF THE LONG TERM
WITH RESPECT TO BOTH TEMPS AND PCPN. GIVEN THE MODEL ISSUES...
TODAY`S LONG TERM FCST WON`T FAVOR ANY SOLUTION IN PARTICULAR THOUGH
IT WOULD SEEM THE 12Z GFS/12Z ECMWF MAY BE WHERE MEDIUM RANGE
GUIDANCE WILL BE HEADING IN UPCOMING RUNS. OVERALL...NEAR NORMAL
TEMPS LATE THIS WEEK SHOULD TREND ABOVE NORMAL BY LATE WEEKEND AND
THEN BEGIN TO FALL BACK CLOSER TO NORMAL. AFTER LINGERING SHRA
CHANCES LATE IN THE WORK WEEK WITH DEPARTING TROF...DEVELOPING GREAT
LAKES/ERN RIDGE SHOULD INITIALLY LEAD TO DRIER WEATHER OVER THE
WEEKEND BEFORE PCPN CHANCES RETURN MON/TUE.
BEGINNING WED NIGHT...TROF WILL BE APPROACHING MAX DEPTH AS 500MB
LOW CLOSES OFF IN THE VCNTY OF NE IA. SFC WAVE WILL DEVELOP/DEEPEN
AND ROTATE THRU ERN WI TOWARD NW WI/WRN UPPER MI OVERNIGHT.
AHEAD OF FRONT/SFC WAVE...WARM CONVEYOR PCPN WILL SWING ACROSS UPPER
MI. NICE DIRECTIONALLY DIFFLUENT UPPER LEVEL FLOW OVERTOP SHARPENING
850MB FRONT WILL AID THE PCPN. LIKELY/CATEGORICAL POPS SPREADING
ACROSS THE AREA APPEARS REASONABLE. CLOUDS/PCPN WILL HOLD MIN TEMPS
IN THE 40S...AND POSSIBLY AROUND 50 E.
WARM CONVEYOR PCPN SHOULD ROTATE OUT OF THE AREA THU...BUT DEEP
CYCLONIC FLOW AND INDICATIONS OF SHORTWAVE PIVOTING AROUND MID LEVEL
LOW TOWARD UPPER MI WILL WORK TO KEEP PCPN CHANCES OVER THE AREA
THRU THE DAY. ABUNDANT CLOUD COVER AND WEAK CAA WILL LIMIT DIURNAL
TEMP RISE. EXPECT HIGHS IN THE UPPER 40S TO MID 50S.
THU NIGHT/FRI...ENTIRE SYSTEM WEAKENS RATHER QUICKLY AND FOCUSED
PCPN SHOULD DIMINISH AS LOW/MID LEVEL WIND FIELDS WEAKEN
DRAMATICALLY. IN FACT...MUCH OF THE GUIDANCE SUGGESTS A TREND TOWARD
MOSTLY DRY LATER THU NIGHT INTO FRI. HOWEVER...WHILE ORGANIZED PCPN
AREAS WILL DIMINISH THU NIGHT...PROXIMITY OF THE CENTER OF WEAKENING
MID LEVEL LOW SUGGESTS MAINTAINING CHC/SLIGHT CHC POPS THU
NIGHT/FRI. MAY END UP BEING MORE OF A DRIZZLE SITUATION WITH PATCHY
-RA. DIURNAL TEMP SWING THU NIGHT/FRI SHOULD CONTINUE TO BE LIMITED
BY CLOUDS AND ALSO BY LITTLE TEMP ADV.
AS WEAKENING SYSTEM BEGINS TO ACCELERATE TO THE NE SAT...WILL OPT
FOR A DRY DAY. BEST SHOT FOR A DRY DAY WILL BE SUN AS AMPLIFYING
RIDGE AXIS DOWNSTREAM OF DEVELOPING WRN TROF SHIFTS ACROSS THE UPPER
LAKES. SUN WILL BE THE WARMEST DAY...WITH MID 50S E AND PERHAPS
AROUND 60F OVER THE W
AS MENTIONED ABOVE...THERE IS VERY LOW CONFIDENCE IN FCST FOR EARLY
NEXT WEEK. EXPECT A CHC OF PCPN AT SOME POINT SUN NIGHT INTO TUE AS
COLD FRONT SLIPS THRU THE AREA. THE 12Z ECMWF/GFS SUGGEST LIMITED
PCPN CHC THAT WILL BE CONFINED MAINLY TO MON OVER THE SCNTRL AND E.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 122 PM EDT TUE OCT 16 2012
EXPECT STEADY RA TO END W-E THIS AFTN AS DRY AIR OVERSPREADS THE UPR
GRT LKS...BUT NOT BEFORE A PERIOD OF MVFR/IFR CONDITIONS IMPACT CMX
AND SAW. ALTHOUGH CONDITIONS SHOULD BE VFR INTO EARLY EVNG AFTER ANY
PCPN ENDS...EXPECT SOME FOG/LO CLD TO DVLP OVERNGT WITH NOCTURNAL
COOLING OF THE FAIRLY MOIST LLVLS UNDER THE DRYING ALF. THE BEST CHC
FOR IFR AND EVEN LIFR CONDITIONS WL BE AT SAW...WITH FAVORABLE
UPSLOPE SSE WIND. ONSET OF DAYTIME HEATING/MIXING ON WED WL BREAK UP
ANY FOG/LO CLD THAT DEVELOPS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 431 PM EDT TUE OCT 16 2012
EXPECT S WINDS UP TO 25-30 KTS OVER THE E HALF TO DIMINISH A BIT
TONIGHT WITH THE ARRIVAL OF A WEAKER PRES GRADIENT. SE WINDS UP TO
25 KTS WILL CONTINUE ON WED IN ADVANCE OF AN APPROACHING DEEP LO
PRES CENTER. THE STRONGEST WINDS WILL BE OVER THE E HALF AGAIN WHERE
THE TERRAIN TENDS TO ENHANCE THESE WINDS.
DEEPENING SFC LOW ROTATING NW THRU NRN WI WED NIGHT WILL RESULT IN
AN INCREASE IN E TO SE WINDS ACROSS LAKE SUPERIOR. NOT OUT OF THE
QUESTION THAT SOME GALE FORCE GUSTS COULD DEVELOP LATE IN THE NIGHT
FROM AROUND WHITEFISH PT TO AROUND ISLE ROYALE. WINDS WILL THEN
DIMINISH DURING THE DAY THU AS LOW PRES WEAKENS. BY THU AFTN...WINDS
SHOULD BE UNDER 15KT OVER WRN LAKE SUPERIOR AND DOWN TO 15 TO 25KT
OVER CNTRL AND ERN LAKE SUPERIOR. BEYOND THU...NO SIGNIFICANT
WEATHER SYSTEMS ARE EXPECTED TO AFFECT THE UPPER LAKES THRU THE
WEEKEND. IN FACT...WEAK PRES GRADIENT MAY LEAD TO A PERIOD OF LIGHT
WINDS UNDER 15KT OVER MUCH OF LAKE SUPERIOR FRI THRU SUN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SHORT TERM...KC
LONG TERM...ROLFSON
AVIATION...KC
MARINE...KC/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
123 PM EDT TUE OCT 16 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 622 AM EDT TUE OCT 16 2012
WV IMAGERY AND RUC ANALYSIS SHOWS A WELL-DEFINED SHORTWAVE MOVING
EAST THROUGH SOUTH DAKOTA. STRONG WAA/ISENTROPIC LIFT AHEAD OF THIS
FEATURE AND LOWERING CONDENSATION PRES DEFICITS HAVE ALLOWED FOR AN
AREA OF LIGHT RAIN TO DEVELOP OVER THE NRN HALF OF MN STRETCHING
INTO FAR NRN WI AND WRN UPR MI. INITIAL VERY DRY AIR AT LOW-LVLS AS
NOTED ON 00Z KMPX AND KINL SNDGS HAS KEPT RAIN LIGHT AND REPORTED
CIGS THUS FAR WITH RAIN HAVE BEEN HIGH-BASED...GENERALLY ABV 5KFT.
WAA MID-HIGH CLOUDS SPREADING INTO UPPER MI HAVE BROUGHT TEMPS UP
ABV FREEZING AT MOST LOCATIONS EARLY THIS MORNING AFTER CHILLY UPPER
20S LOWS REACHED EARLIER IN THE EVENING AT MANY CENTRAL AND ERN
LOCATIONS.
AS THE 850-700 MB WARM FRONT NOW REACHING INTO THE WRN CWA MOVES
EAST THROUGH THE AREA TODAY...PCPN WILL SPREAD EAST ACROSS THE CWA.
LIKELY-CATEGORICAL POPS ARE WARRANTED...ESPECIALLY ACROSS THE NRN
TIER AND ERN COUNTIES WHERE THE STRONGEST ISENTROPIC LIFT AND BEST
LLVL MOISTURE TRANSPORT IS LOCATED ALONG/AHEAD OF THE ADVANCING 850
MB WARM FRONT...AS PROGGED BY 00-06Z MODELS. BELIEVE INITIALLY DRY
LOW-LVLS MAY NEGATIVELY IMPACT PCPN AMOUNTS...KEEPING RAINFALL
CLOSER TO STINGIER NAM/WRF-ARW AMOUNTS OF .1-.2 INCH NORTH TO LESS
THAN .1 INCH SOUTH. MODELS HAVE BEEN CONSISTENT WITH THE PCPN ENDING
OVER THE WEST BY EARLY AFTERNOON AND OVER THE EASTERN COUNTIES IN
TUE EVENING AS Q-VECT DIV/SUBSIDENCE SPREADS IN FROM THE WEST IN THE
WAKE OF THE SHORTWAVE AND ASSOC WARM FRONT. LOW CLOUDS/FOG WILL
REMAIN A CONCERN LATE TONIGHT DUE TO CLEARING SKIES FROM WEST AND
LEFTOVER LOW LEVEL MOISTURE FROM AFTN/EVENING RAINFALL SO HAVE
MAINTAINED MENTION OF FOG...ESPECIALLY CENTRAL AND EAST WHERE
UPSLOPE/ONSHORE FLOW OFF LAKE MI COULD ENHANCE FOG CHCS.
WAA WILL DRAW ENOUGH WARM AIR INTO THE REGION TO PUSH MAX READINGS
TODAY INTO UPPER 50S WEST WHILE TEMPS LINGER AROUND 50 OVER THE
EAST. TEMPS SHOULD STAY RELATIVELY MILD TONIGHT (IN THE 40S) AS WE
REMAIN IN WARM SECTOR AHEAD OF DEEPENING SFC LOW NR LAKE WINNIPEG
AND OCCLUDED FRONT STRETCHING INTO THE PLAINS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 622 AM EDT TUE OCT 16 2012
MAJORITY OF FOCUS IN THE LONG TERM IS ON DEEP UPPER TROUGH THAT DIGS
INTO CENTRAL CONUS WEDNESDAY AND THURSDAY. ASSOCIATED SFC TROUGH IS
INITIALLY STRUNG OUT FROM SOUTHERN SASKATCHEWAN AND MANITOBA INTO
MIDDLE MISSISSIPPI RIVER VALLEY ON WEDNESDAY...THEN PHASES INTO A
985-990MB SFC LOW OVER UPPER GREAT LAKES BY THURSDAY MORNING. RAIN
CHANCES ON WEDNESDAY DRIVEN BY BROAD UPPER DIFFLUENCE BTWN THE CNTRL
CONUS UPR LOW AND RIDGE OVER THE NORTHEAST CONUS. MOISTURE ADVECTION
AT H85 ALSO A FACTOR. GOING WITH PREFERRED ECMWF MODELS DEPICTION...
STRONGER UPPER FORCING /MID-LEVEL HEIGHT FALLS AND H85-H7
FRONTOGENESIS/ HOLDS OFF OVR UPR MICHIGAN UNTIL LATER WEDNESDAY AFTN
OVER WESTERN CWA AND ACROSS REST OF CWA ON WEDNESDAY NIGHT. MAX
TEMPS ON WEDNESDAY REMAIN TRICKY PROPOSITION AS IT IS FEASIBLE THERE
COULD BE SOME SUNSHINE THROUGH MIDDAY FOR PORTIONS OF CWA /DEPENDS
ON HOW QUICKLY ANY FOG/LOW CLOUDS GET OUT OF THE WAY IN THE MORNING/
BUT GIVEN ANY SUNSHINE...TEMPS ALOFT ARE PRETTY WARM /H85 TEMPS
PUSHING +10C AND H925 TEMPS OVR +10C/ SO WOULD NOT TAKE MUCH MIXING
TO ALLOW TEMPS TO PUSH PAST 60 DEGREES. KEPT TEMPS OVER FAR WEST
COOLER WITH MORE CLOUDS AND PRECIP EXPECTED BUT TEMPS ELSEWHERE
SHOULD TOP OUT IN THE 60S WHICH WOULD BE THE WARMEST DAY SEEN SINCE
OCTOBER 4TH WHEN TEMPS REACHED UPPER 60S.
NO REAL CHANGE TO PREVIOUS THINKING IN THAT WEDNESDAY NIGHT TURNS
OUT TO BE WET NIGHT OVER CWA. SWATH OF WARM CONVEYOR MOISTURE AND A
BIT OF A TROWAL REGION PIVOT ACROSS CWA AS SFC LOW OCCLUDES WHICH
PUTS AREA IN REGION OF MORE STEADY RAIN MOST OF THE NIGHT. HAVE
LINGERED HIGHER POPS ON THURSDAY OVER KEWEENAW AS THAT AREA REMAINS
ON SOUTHERN EDGE OF H85 THERMAL GRADIENT AND WITHIN H3 JET CORE.
SHORTWAVE ROTATING NORTH IN PERIFERY OF BROAD UPPER LOW MAY BRING
INCREASE TO POPS FOR MUCH OF CWA THURSDAY AFTN/EVENING. PVA FM THE
WAVE AND MORE PERSISTENT LOW-LEVEL MOISTURE ADVECTION IS FORECAST
OVER THE EAST...ALONG WITH SOME ELEVATED INSTABILITY AS SI/S FALL
TOWARD 0C. ANY DETAIL IS REALLY A ROUGH GUESS AS SENSIBLE WEATHER
WILL BE ALTERED WITH JUST A SLIGHT SHIFT IN THE UPR LOW CENTER. DRY
AIR INTRUSION THAT MODELS HAVE HINTED AT FOR A WHILE SHOWS UP LATER
THURSDAY NIGHT INTO FRIDAY. EXPECT STEADIER PRECIP TO DIMINISH BY
THAT TIME...THOUGH CERTAINLY COULD SEE LOW CLOUDS AND MAYBE SOME
LIGHTER PRECIP/DRIZZLE LINGER. CHANCES FOR MORE SIGNIFICANT PRECIP
WOULD BE ENHANCED WHERE THE LOW-LEVEL WINDS ARE MOST ONSHORE AND/OR
PROVIDE MOST UPSLOPE LIFT.
LOW THEN WOBBLES SOUTH/SOUTHEAST LATER FRIDAY AND IS FINALLY KICKED
OFF TOWARD EASTERN CANADA/NEW ENGLAND THROUGH THE UPCOMING WEEKEND.
AFTER SOME WARMER THAN NORMAL TEMPS THROUGH MIDWEEK...TEMPS
GRADUALLY TREND SLIGHTLY BLO NORMAL BY FRIDAY AS COLD AIR ADVECTION
AFFECTS THE UPR LAKES REGION. INTO THE WEEKEND...HAVE SIDED WITH
MORE CONSISTENT ECMWF THAT SHOWS A GENERALLY DRY WEEKEND AS UPR
LAKES IS BTWN EXITING UPR LOW AND ANOTHER TROUGH SLIDING TOWARD
NORTHERN PLAINS BY SUNDAY. SINCE SFC TROUGH DEVELOPS OVER THE PLAINS
BY SUNDAY SW WINDS SHOULD PUSH TEMPS BACK TOWARD NORMAL THROUGH THE
WEEKEND IF NOT SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 122 PM EDT TUE OCT 16 2012
EXPECT STEADY RA TO END W-E THIS AFTN AS DRY AIR OVERSPREADS THE UPR
GRT LKS...BUT NOT BEFORE A PERIOD OF MVFR/IFR CONDITIONS IMPACT CMX
AND SAW. ALTHOUGH CONDITIONS SHOULD BE VFR INTO EARLY EVNG AFTER ANY
PCPN ENDS...EXPECT SOME FOG/LO CLD TO DVLP OVERNGT WITH NOCTURNAL
COOLING OF THE FAIRLY MOIST LLVLS UNDER THE DRYING ALF. THE BEST CHC
FOR IFR AND EVEN LIFR CONDITIONS WL BE AT SAW...WITH FAVORABLE
UPSLOPE SSE WIND. ONSET OF DAYTIME HEATING/MIXING ON WED WL BREAK UP
ANY FOG/LO CLD THAT DEVELOPS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 622 AM EDT TUE OCT 16 2012
LOW PRESSURE TROUGH APPROACHING FROM THE NRN PLAINS WILL RESULT
IN SOUTH WINDS OF 15 TO 25 KT WITH AREAS TO NEAR 30 KT OVER ERN LAKE
SUPERIOR THIS AFTERNOON AND EVENING. A DEEPER LOW PRESSURE SYSTEM
MOVING INTO THE UPPER GREAT LAKES ON THURSDAY COULD CAUSE AN
INCREASE IN ERLY WINDS TO 30 KT LATE WED NIGHT AND EARLY
THURSDAY. OTHERWISE...WINDS IN THE VICINITY OF THE LOW SHOULD
GENERALLY REMAIN LESS THAN 20 KTS WEDNESDAY THROUGH SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...KC
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
757 AM EDT TUE OCT 16 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 622 AM EDT TUE OCT 16 2012
WV IMAGERY AND RUC ANALYSIS SHOWS A WELL-DEFINED SHORTWAVE MOVING
EAST THROUGH SOUTH DAKOTA. STRONG WAA/ISENTROPIC LIFT AHEAD OF THIS
FEATURE AND LOWERING CONDENSATION PRES DEFICITS HAVE ALLOWED FOR AN
AREA OF LIGHT RAIN TO DEVELOP OVER THE NRN HALF OF MN STRETCHING
INTO FAR NRN WI AND WRN UPR MI. INITIAL VERY DRY AIR AT LOW-LVLS AS
NOTED ON 00Z KMPX AND KINL SNDGS HAS KEPT RAIN LIGHT AND REPORTED
CIGS THUS FAR WITH RAIN HAVE BEEN HIGH-BASED...GENERALLY ABV 5KFT.
WAA MID-HIGH CLOUDS SPREADING INTO UPPER MI HAVE BROUGHT TEMPS UP
ABV FREEZING AT MOST LOCATIONS EARLY THIS MORNING AFTER CHILLY UPPER
20S LOWS REACHED EARLIER IN THE EVENING AT MANY CENTRAL AND ERN
LOCATIONS.
AS THE 850-700 MB WARM FRONT NOW REACHING INTO THE WRN CWA MOVES
EAST THROUGH THE AREA TODAY...PCPN WILL SPREAD EAST ACROSS THE CWA.
LIKELY-CATEGORICAL POPS ARE WARRANTED...ESPECIALLY ACROSS THE NRN
TIER AND ERN COUNTIES WHERE THE STRONGEST ISENTROPIC LIFT AND BEST
LLVL MOISTURE TRANSPORT IS LOCATED ALONG/AHEAD OF THE ADVANCING 850
MB WARM FRONT...AS PROGGED BY 00-06Z MODELS. BELIEVE INITIALLY DRY
LOW-LVLS MAY NEGATIVELY IMPACT PCPN AMOUNTS...KEEPING RAINFALL
CLOSER TO STINGIER NAM/WRF-ARW AMOUNTS OF .1-.2 INCH NORTH TO LESS
THAN .1 INCH SOUTH. MODELS HAVE BEEN CONSISTENT WITH THE PCPN ENDING
OVER THE WEST BY EARLY AFTERNOON AND OVER THE EASTERN COUNTIES IN
TUE EVENING AS Q-VECT DIV/SUBSIDENCE SPREADS IN FROM THE WEST IN THE
WAKE OF THE SHORTWAVE AND ASSOC WARM FRONT. LOW CLOUDS/FOG WILL
REMAIN A CONCERN LATE TONIGHT DUE TO CLEARING SKIES FROM WEST AND
LEFTOVER LOW LEVEL MOISTURE FROM AFTN/EVENING RAINFALL SO HAVE
MAINTAINED MENTION OF FOG...ESPECIALLY CENTRAL AND EAST WHERE
UPSLOPE/ONSHORE FLOW OFF LAKE MI COULD ENHANCE FOG CHCS.
WAA WILL DRAW ENOUGH WARM AIR INTO THE REGION TO PUSH MAX READINGS
TODAY INTO UPPER 50S WEST WHILE TEMPS LINGER AROUND 50 OVER THE
EAST. TEMPS SHOULD STAY RELATIVELY MILD TONIGHT (IN THE 40S) AS WE
REMAIN IN WARM SECTOR AHEAD OF DEEPENING SFC LOW NR LAKE WINNIPEG
AND OCCLUDED FRONT STRETCHING INTO THE PLAINS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 622 AM EDT TUE OCT 16 2012
MAJORITY OF FOCUS IN THE LONG TERM IS ON DEEP UPPER TROUGH THAT DIGS
INTO CENTRAL CONUS WEDNESDAY AND THURSDAY. ASSOCIATED SFC TROUGH IS
INITIALLY STRUNG OUT FROM SOUTHERN SASKATCHEWAN AND MANITOBA INTO
MIDDLE MISSISSIPPI RIVER VALLEY ON WEDNESDAY...THEN PHASES INTO A
985-990MB SFC LOW OVER UPPER GREAT LAKES BY THURSDAY MORNING. RAIN
CHANCES ON WEDNESDAY DRIVEN BY BROAD UPPER DIFFLUENCE BTWN THE CNTRL
CONUS UPR LOW AND RIDGE OVER THE NORTHEAST CONUS. MOISTURE ADVECTION
AT H85 ALSO A FACTOR. GOING WITH PREFERRED ECMWF MODELS DEPICTION...
STRONGER UPPER FORCING /MID-LEVEL HEIGHT FALLS AND H85-H7
FRONTOGENESIS/ HOLDS OFF OVR UPR MICHIGAN UNTIL LATER WEDNESDAY AFTN
OVER WESTERN CWA AND ACROSS REST OF CWA ON WEDNESDAY NIGHT. MAX
TEMPS ON WEDNESDAY REMAIN TRICKY PROPOSITION AS IT IS FEASIBLE THERE
COULD BE SOME SUNSHINE THROUGH MIDDAY FOR PORTIONS OF CWA /DEPENDS
ON HOW QUICKLY ANY FOG/LOW CLOUDS GET OUT OF THE WAY IN THE MORNING/
BUT GIVEN ANY SUNSHINE...TEMPS ALOFT ARE PRETTY WARM /H85 TEMPS
PUSHING +10C AND H925 TEMPS OVR +10C/ SO WOULD NOT TAKE MUCH MIXING
TO ALLOW TEMPS TO PUSH PAST 60 DEGREES. KEPT TEMPS OVER FAR WEST
COOLER WITH MORE CLOUDS AND PRECIP EXPECTED BUT TEMPS ELSEWHERE
SHOULD TOP OUT IN THE 60S WHICH WOULD BE THE WARMEST DAY SEEN SINCE
OCTOBER 4TH WHEN TEMPS REACHED UPPER 60S.
NO REAL CHANGE TO PREVIOUS THINKING IN THAT WEDNESDAY NIGHT TURNS
OUT TO BE WET NIGHT OVER CWA. SWATH OF WARM CONVEYOR MOISTURE AND A
BIT OF A TROWAL REGION PIVOT ACROSS CWA AS SFC LOW OCCLUDES WHICH
PUTS AREA IN REGION OF MORE STEADY RAIN MOST OF THE NIGHT. HAVE
LINGERED HIGHER POPS ON THURSDAY OVER KEWEENAW AS THAT AREA REMAINS
ON SOUTHERN EDGE OF H85 THERMAL GRADIENT AND WITHIN H3 JET CORE.
SHORTWAVE ROTATING NORTH IN PERIFERY OF BROAD UPPER LOW MAY BRING
INCREASE TO POPS FOR MUCH OF CWA THURSDAY AFTN/EVENING. PVA FM THE
WAVE AND MORE PERSISTENT LOW-LEVEL MOISTURE ADVECTION IS FORECAST
OVER THE EAST...ALONG WITH SOME ELEVATED INSTABILITY AS SI/S FALL
TOWARD 0C. ANY DETAIL IS REALLY A ROUGH GUESS AS SENSIBLE WEATHER
WILL BE ALTERED WITH JUST A SLIGHT SHIFT IN THE UPR LOW CENTER. DRY
AIR INTRUSION THAT MODELS HAVE HINTED AT FOR A WHILE SHOWS UP LATER
THURSDAY NIGHT INTO FRIDAY. EXPECT STEADIER PRECIP TO DIMINISH BY
THAT TIME...THOUGH CERTAINLY COULD SEE LOW CLOUDS AND MAYBE SOME
LIGHTER PRECIP/DRIZZLE LINGER. CHANCES FOR MORE SIGNIFICANT PRECIP
WOULD BE ENHANCED WHERE THE LOW-LEVEL WINDS ARE MOST ONSHORE AND/OR
PROVIDE MOST UPSLOPE LIFT.
LOW THEN WOBBLES SOUTH/SOUTHEAST LATER FRIDAY AND IS FINALLY KICKED
OFF TOWARD EASTERN CANADA/NEW ENGLAND THROUGH THE UPCOMING WEEKEND.
AFTER SOME WARMER THAN NORMAL TEMPS THROUGH MIDWEEK...TEMPS
GRADUALLY TREND SLIGHTLY BLO NORMAL BY FRIDAY AS COLD AIR ADVECTION
AFFECTS THE UPR LAKES REGION. INTO THE WEEKEND...HAVE SIDED WITH
MORE CONSISTENT ECMWF THAT SHOWS A GENERALLY DRY WEEKEND AS UPR
LAKES IS BTWN EXITING UPR LOW AND ANOTHER TROUGH SLIDING TOWARD
NORTHERN PLAINS BY SUNDAY. SINCE SFC TROUGH DEVELOPS OVER THE PLAINS
BY SUNDAY SW WINDS SHOULD PUSH TEMPS BACK TOWARD NORMAL THROUGH THE
WEEKEND IF NOT SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 748 AM EDT TUE OCT 16 2012
A WARM FRONT MOVING ACROSS THE AREA WILL SPREAD LIGHT RAIN ACROSS
THE TAF SITES TODAY. FAIRLY DRY AIR AT LOW LEVELS HOWEVER SHOULD KEEP
CONDITIONS VFR AT ALL TAF SITES DESPITE THE RAIN. THERE WILL BE SOME
LLWS AT KCMX AND KSAW THIS MORNING. RAIN WILL LIFT EAST OF THE TAF
SITES IN THE AFTERNOON. POSSIBLE CLEARING TONIGHT WILL BRING THE
POTENTIAL FOR FOG LATE TONIGHT...ESPECIALLY AT KSAW WHERE A
DEVELOPING SSE UPSLOPE FLOW COULD LEAD TO VLIFR CONDITIONS IN
STRATUS/FOG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 622 AM EDT TUE OCT 16 2012
LOW PRESSURE TROUGH APPROACHING FROM THE NRN PLAINS WILL RESULT
IN SOUTH WINDS OF 15 TO 25 KT WITH AREAS TO NEAR 30 KT OVER ERN LAKE
SUPERIOR THIS AFTERNOON AND EVENING. A DEEPER LOW PRESSURE SYSTEM
MOVING INTO THE UPPER GREAT LAKES ON THURSDAY COULD CAUSE AN
INCREASE IN ERLY WINDS TO 30 KT LATE WED NIGHT AND EARLY
THURSDAY. OTHERWISE...WINDS IN THE VICINITY OF THE LOW SHOULD
GENERALLY REMAIN LESS THAN 20 KTS WEDNESDAY THROUGH SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
623 AM EDT TUE OCT 16 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 622 AM EDT TUE OCT 16 2012
WV IMAGERY AND RUC ANALYSIS SHOWS A WELL-DEFINED SHORTWAVE MOVING
EAST THROUGH SOUTH DAKOTA. STRONG WAA/ISENTROPIC LIFT AHEAD OF THIS
FEATURE AND LOWERING CONDENSATION PRES DEFICITS HAVE ALLOWED FOR AN
AREA OF LIGHT RAIN TO DEVELOP OVER THE NRN HALF OF MN STRETCHING
INTO FAR NRN WI AND WRN UPR MI. INITIAL VERY DRY AIR AT LOW-LVLS AS
NOTED ON 00Z KMPX AND KINL SNDGS HAS KEPT RAIN LIGHT AND REPORTED
CIGS THUS FAR WITH RAIN HAVE BEEN HIGH-BASED...GENERALLY ABV 5KFT.
WAA MID-HIGH CLOUDS SPREADING INTO UPPER MI HAVE BROUGHT TEMPS UP
ABV FREEZING AT MOST LOCATIONS EARLY THIS MORNING AFTER CHILLY UPPER
20S LOWS REACHED EARLIER IN THE EVENING AT MANY CENTRAL AND ERN
LOCATIONS.
AS THE 850-700 MB WARM FRONT NOW REACHING INTO THE WRN CWA MOVES
EAST THROUGH THE AREA TODAY...PCPN WILL SPREAD EAST ACROSS THE CWA.
LIKELY-CATEGORICAL POPS ARE WARRANTED...ESPECIALLY ACROSS THE NRN
TIER AND ERN COUNTIES WHERE THE STRONGEST ISENTROPIC LIFT AND BEST
LLVL MOISTURE TRANSPORT IS LOCATED ALONG/AHEAD OF THE ADVANCING 850
MB WARM FRONT...AS PROGGED BY 00-06Z MODELS. BELIEVE INITIALLY DRY
LOW-LVLS MAY NEGATIVELY IMPACT PCPN AMOUNTS...KEEPING RAINFALL
CLOSER TO STINGIER NAM/WRF-ARW AMOUNTS OF .1-.2 INCH NORTH TO LESS
THAN .1 INCH SOUTH. MODELS HAVE BEEN CONSISTENT WITH THE PCPN ENDING
OVER THE WEST BY EARLY AFTERNOON AND OVER THE EASTERN COUNTIES IN
TUE EVENING AS Q-VECT DIV/SUBSIDENCE SPREADS IN FROM THE WEST IN THE
WAKE OF THE SHORTWAVE AND ASSOC WARM FRONT. LOW CLOUDS/FOG WILL
REMAIN A CONCERN LATE TONIGHT DUE TO CLEARING SKIES FROM WEST AND
LEFTOVER LOW LEVEL MOISTURE FROM AFTN/EVENING RAINFALL SO HAVE
MAINTAINED MENTION OF FOG...ESPECIALLY CENTRAL AND EAST WHERE
UPSLOPE/ONSHORE FLOW OFF LAKE MI COULD ENHANCE FOG CHCS.
WAA WILL DRAW ENOUGH WARM AIR INTO THE REGION TO PUSH MAX READINGS
TODAY INTO UPPER 50S WEST WHILE TEMPS LINGER AROUND 50 OVER THE
EAST. TEMPS SHOULD STAY RELATIVELY MILD TONIGHT (IN THE 40S) AS WE
REMAIN IN WARM SECTOR AHEAD OF DEEPENING SFC LOW NR LAKE WINNIPEG
AND OCCLUDED FRONT STRETCHING INTO THE PLAINS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 622 AM EDT TUE OCT 16 2012
MAJORITY OF FOCUS IN THE LONG TERM IS ON DEEP UPPER TROUGH THAT DIGS
INTO CENTRAL CONUS WEDNESDAY AND THURSDAY. ASSOCIATED SFC TROUGH IS
INITIALLY STRUNG OUT FROM SOUTHERN SASKATCHEWAN AND MANITOBA INTO
MIDDLE MISSISSIPPI RIVER VALLEY ON WEDNESDAY...THEN PHASES INTO A
985-990MB SFC LOW OVER UPPER GREAT LAKES BY THURSDAY MORNING. RAIN
CHANCES ON WEDNESDAY DRIVEN BY BROAD UPPER DIFFLUENCE BTWN THE CNTRL
CONUS UPR LOW AND RIDGE OVER THE NORTHEAST CONUS. MOISTURE ADVECTION
AT H85 ALSO A FACTOR. GOING WITH PREFERRED ECMWF MODELS DEPICTION...
STRONGER UPPER FORCING /MID-LEVEL HEIGHT FALLS AND H85-H7
FRONTOGENESIS/ HOLDS OFF OVR UPR MICHIGAN UNTIL LATER WEDNESDAY AFTN
OVER WESTERN CWA AND ACROSS REST OF CWA ON WEDNESDAY NIGHT. MAX
TEMPS ON WEDNESDAY REMAIN TRICKY PROPOSITION AS IT IS FEASIBLE THERE
COULD BE SOME SUNSHINE THROUGH MIDDAY FOR PORTIONS OF CWA /DEPENDS
ON HOW QUICKLY ANY FOG/LOW CLOUDS GET OUT OF THE WAY IN THE MORNING/
BUT GIVEN ANY SUNSHINE...TEMPS ALOFT ARE PRETTY WARM /H85 TEMPS
PUSHING +10C AND H925 TEMPS OVR +10C/ SO WOULD NOT TAKE MUCH MIXING
TO ALLOW TEMPS TO PUSH PAST 60 DEGREES. KEPT TEMPS OVER FAR WEST
COOLER WITH MORE CLOUDS AND PRECIP EXPECTED BUT TEMPS ELSEWHERE
SHOULD TOP OUT IN THE 60S WHICH WOULD BE THE WARMEST DAY SEEN SINCE
OCTOBER 4TH WHEN TEMPS REACHED UPPER 60S.
NO REAL CHANGE TO PREVIOUS THINKING IN THAT WEDNESDAY NIGHT TURNS
OUT TO BE WET NIGHT OVER CWA. SWATH OF WARM CONVEYOR MOISTURE AND A
BIT OF A TROWAL REGION PIVOT ACROSS CWA AS SFC LOW OCCLUDES WHICH
PUTS AREA IN REGION OF MORE STEADY RAIN MOST OF THE NIGHT. HAVE
LINGERED HIGHER POPS ON THURSDAY OVER KEWEENAW AS THAT AREA REMAINS
ON SOUTHERN EDGE OF H85 THERMAL GRADIENT AND WITHIN H3 JET CORE.
SHORTWAVE ROTATING NORTH IN PERIFERY OF BROAD UPPER LOW MAY BRING
INCREASE TO POPS FOR MUCH OF CWA THURSDAY AFTN/EVENING. PVA FM THE
WAVE AND MORE PERSISTENT LOW-LEVEL MOISTURE ADVECTION IS FORECAST
OVER THE EAST...ALONG WITH SOME ELEVATED INSTABILITY AS SI/S FALL
TOWARD 0C. ANY DETAIL IS REALLY A ROUGH GUESS AS SENSIBLE WEATHER
WILL BE ALTERED WITH JUST A SLIGHT SHIFT IN THE UPR LOW CENTER. DRY
AIR INTRUSION THAT MODELS HAVE HINTED AT FOR A WHILE SHOWS UP LATER
THURSDAY NIGHT INTO FRIDAY. EXPECT STEADIER PRECIP TO DIMINISH BY
THAT TIME...THOUGH CERTAINLY COULD SEE LOW CLOUDS AND MAYBE SOME
LIGHTER PRECIP/DRIZZLE LINGER. CHANCES FOR MORE SIGNIFICANT PRECIP
WOULD BE ENHANCED WHERE THE LOW-LEVEL WINDS ARE MOST ONSHORE AND/OR
PROVIDE MOST UPSLOPE LIFT.
LOW THEN WOBBLES SOUTH/SOUTHEAST LATER FRIDAY AND IS FINALLY KICKED
OFF TOWARD EASTERN CANADA/NEW ENGLAND THROUGH THE UPCOMING WEEKEND.
AFTER SOME WARMER THAN NORMAL TEMPS THROUGH MIDWEEK...TEMPS
GRADUALLY TREND SLIGHTLY BLO NORMAL BY FRIDAY AS COLD AIR ADVECTION
AFFECTS THE UPR LAKES REGION. INTO THE WEEKEND...HAVE SIDED WITH
MORE CONSISTENT ECMWF THAT SHOWS A GENERALLY DRY WEEKEND AS UPR
LAKES IS BTWN EXITING UPR LOW AND ANOTHER TROUGH SLIDING TOWARD
NORTHERN PLAINS BY SUNDAY. SINCE SFC TROUGH DEVELOPS OVER THE PLAINS
BY SUNDAY SW WINDS SHOULD PUSH TEMPS BACK TOWARD NORMAL THROUGH THE
WEEKEND IF NOT SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 130 AM EDT TUE OCT 16 2012
A TROUGH WILL MOVE TOWARD THE AREA LATE TONIGHT BRINGING THICKENING
CLOUDS AND THE POTENTIAL FOR SOME LIGHT RAIN LATE TONIGHT. EXPECT
RAIN WITH MVFR CIGS TO MOVE IN TUESDAY AT KCMX AND CONDITIONS TO
STAY VFR THROUGH THE PERIOD AT KSAW AND KIWD. THERE WILL BE SOME
LLWS AT TIMES AT ALL SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 622 AM EDT TUE OCT 16 2012
LOW PRESSURE TROUGH APPROACHING FROM THE NRN PLAINS WILL RESULT
IN SOUTH WINDS OF 15 TO 25 KT WITH AREAS TO NEAR 30 KT OVER ERN LAKE
SUPERIOR THIS AFTERNOON AND EVENING. A DEEPER LOW PRESSURE SYSTEM
MOVING INTO THE UPPER GREAT LAKES ON THURSDAY COULD CAUSE AN
INCREASE IN ERLY WINDS TO 30 KT LATE WED NIGHT AND EARLY
THURSDAY. OTHERWISE...WINDS IN THE VICINITY OF THE LOW SHOULD
GENERALLY REMAIN LESS THAN 20 KTS WEDNESDAY THROUGH SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
145 AM EDT TUE OCT 16 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 414 PM EDT MON OCT 15 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH EAST
OF LAKE HURON LEAVING MAINLY ZONAL FLOW TO THE WEST FROM THE PAC NW TO
THE UPPER MS VALLEY. AN UPSTREAM SHORTWAVE TROUGH WAS MOVING FROM
THE NRN ROCKIES INTO THE NRN PLAINS. AT THE SFC...A RIDGE WAS
BUILDING ACROSS WRN LAKE SUPERIOR AND W UPPER MI. SRLY WINDS WERE
INCREASING OVER MN AHEAD OF A TROUGH FROM SRN MANITOBA INTO THE
CNTRL DAKOTAS. VIS LOOP SHOWED CLEARING SKIES OVER THE W HALF OF
UPPER MI. HOWEVER...HIGH CLOUDS SUPPORTED BY WAA AHEAD OF THE TROUGH
WERE QUICKLY STREAMING FROM MN INTO WRN WI. SOME LIGHT RAIN HAD ALSO
DEVELOPED FROM NEAR WINNIPEG INTO NW MN WITH WAA/ISENTROPIC LIFT
AHEAD OF THE TROUGH.
THE MODELS WERE IN GOOD AGREEMENT WITH THE MID LEVEL TROUGH DIGGING
FROM THE NRN PLAINS INTO THE UPPER MS VALLEY TONIGHT INTO TUE.
EXPECT THE AREA OF RAIN TO THE WEST TO EXPAND LATE TONIGHT AND
SPREAD INTO THE WRN CWA AS 925-850 MB MOISTURE TRANSPORT AND
295-300K ISENTROPIC LIFT INCREASE. AS THE 850-700 MB WARM FRONT
MOVES THROUGH THE AREA TUE...PCPN WILL SPREAD ACROSS THE CWA.
ALTHOUGH LIKELY-CATEGORICAL POPS WERE WARRANTED...THE HEAVIER PCPN
(INTO THE 0.25 TO 0.50 RANGE) IS EXPECTED MAINLY ACROSS THE NORTH
AND EAST FROM THE KEWEENAW INTO THE ERN CWA WHERE THE STRONGEST LIFT
AHEAD OF THE 850 MB WARM FRONT IS PROGGED....PER NAM/REGIONAL-GEM.
MODELS TIMING HAS ALSO BEEN CONSISTENT WITH THE PCPN ENDING OVER THE
WEST BY EARLY AFTERNOON AND OVER THE EAST LATE.
TEMPS WILL DROP INTO THE LOW TO MID 30S THIS EVENING BEFORE THE
CLOUDS THICKEN AND SRLY WINDS INCREASE RESULTING IN SLOWLY CLIMBING
TEMPS OVERNIGHT. AS THE PCPN ENDS TUE AFTERNOON...WAA WILL ALSO DRAW
ENOUGH WARM AIR INTO THE REGION TO PUSH MAX READINGS INTO UPPER 50S
WEST WHILE TEMPS LINGER AROUND 50 OVER THE EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 PM EDT MON OCT 15 2012
MID WEEK WILL REMAIN UNSETTLED AS A DEEP UPPER TROUGH OVER THE
CANADIAN PRAIRIE PROVINCES CLOSES OFF OVER THE UPPER MIDWEST/GREAT
LAKES. THIS WILL ALLOW FOR PRECIPITATION CHANCES THROUGH THURSDAY
WITH AT OR SLIGHTLY BELOW NORMAL TEMPERATURES.
FOR THE DETAILS...EXPECT THE WARM ADVECTION/ISENTROPIC LIFT PCPN
ASSOCIATED WITH THE 850MB WARM FRONT TO MOVE EAST OF THE FORECAST
AREA TUESDAY NIGHT...LEADING TO THE AREA BEING IN THE WARM SECTOR
AHEAD OF THE DEEP SFC LOW AND OCCLUDED FRONT EXTENDING FROM LAKE
WINNIPEG INTO THE PLAINS. WILL MAINTAIN LOW CHANCE POPS IN THE
EVENING EAST OF MARQUETTE DUE TO CONTINUED WEAK ISENTROPIC LIFT AND
MID LVL Q-VECT CONVERGENCE. LOW CLOUDS/FOG WILL REMAIN A CONCERN
OVERNIGHT DUE TO CLEARING SKIES AND LEFTOVER LOW LEVEL MOISTURE FROM
AFTN/EVENING RAINFALL AND AS SUCH HAVE MAINTAINED FOG CHANCES.
THE OCCLUDED FRONT WILL MOVE EAST ON WEDNESDAY AS THE UPPER SYSTEM
CLOSES OFF. EXPECT A BAND OF SHOWERS TO MOVE INTO THE WESTERN U.P.
WEDNESDAY AFTERNOON ASSOCIATED WITH PRECIPITABLE WATER VALUES IN
EXCESS OF 1 INCH AND MID LVL Q-VECTOR CONVERGENCE. DUE TO THE LOW
CLOSING OFF...THE BAND OF SHOWERS WILL ONLY SLOWLY MOVE EAST WED
AFTN/NIGHT. IN FACT...THERE WILL LIKELY BE A PROLONGED PERIOD OF
STEADY RAIN WED EVENING ACROSS UPPER MICHIGAN DUE TO THE ROTATION
AND TIGHTENING OF THE 850MB ISOTHERMS CONTRIBUTING TO INCREASED
FN/FS VECTOR CONVERGENCE IN THE TROWAL REGION. WILL THEREFORE
MAINTAIN LIKELY POPS ACROSS THE ENTIRE U.P. WED NIGHT.
TRICKY AND UNCERTAIN FORECAST FOR THURSDAY. THE ECMWF SUGGESTS THAT
MOST OF THE U.P. WILL BE DRY WITH THE COMMA HEAD MOISTURE/PCPN BACK
INTO MN AND NW WISCONSIN DUE TO THE UPPER LOW BEING FURTHER WEST
THAN THE GFS WHICH HAS THE UPPER LOW OVERHEAD. AM THINKING THAT THE
BEST CHANCES FOR PCPN WILL BE ACROSS THE WEST AND HAVE OPTED TO
MAINTAIN HIGH CHANCE POPS FOR THAT AREA. DUE TO SIGNIFICANT
UNCERTAINTY...WILL STILL NEED TO MAINTAIN CHANCE POPS TO THE EAST.
CONFIDENCE IN THE EXTENDED FORECAST FOR FRIDAY-MONDAY STILL QUITE
LOW WITH DIFFERENCES BETWEEN THE ECWMF...GFS AND CANADIAN IN HOW
FAST THE GREAT LAKES CLOSED LOW EJECTS TO THE NORTHEAST. TEND TO
BELIEVE THE SLOWER ECMWF SOLUTION WHICH WOULD KEEP A DRIER FORECAST
FOR THE UPPER LAKES FOR THE WEEKEND DUE TO UPPER RIDGING HANGING ON
ACROSS THE UPPER MIDWEST. THE BELOW CONFIDENCE FORECAST NOT ONLY
APPLIES TO PRECIPITATION CHANCES...BUT ALSO TO TEMPERATURES AS THE
ECMWF WOULD BE WARMER COMPARED TO THE CLOUDY/COOL GFS.
WITH ALL OF THIS SAID...WILL TREND TOWARD THE 00Z AND 12Z ECMWF AND
LOWER POPS TO SLIGHT CHANCE OR LOW CHANCE POPS EACH DAY IN THE
EXTENDED. IN FACT IF THE 00Z ECMWF VERIFIES IT WILL END UP BEING A
DECENT WEEKEND. ON THE OTHER HAND...IF THE GFS VERIFIES IT COULD BE
MUCH WETTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 130 AM EDT TUE OCT 16 2012
A TROUGH WILL MOVE TOWARD THE AREA LATE TONIGHT BRINGING THICKENING
CLOUDS AND THE POTENTIAL FOR SOME LIGHT RAIN LATE TONIGHT. EXPECT
RAIN WITH MVFR CIGS TO MOVE IN TUESDAY AT KCMX AND CONDITIONS TO
STAY VFR THROUGH THE PERIOD AT KSAW AND KIWD. THERE WILL BE SOME
LLWS AT TIMES AT ALL SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 PM EDT MON OCT 15 2012
WINDS WILL CONTINUE TO DIMINISH THIS EVENING AS HIGH PRES BUILDS
INTO THE REGION. ANOTHER LOW PRESSURE TROUGH APPROACHING THE UPPER
GREAT LAKES LATE TONIGHT WILL RESULT IN SOUTH WINDS OF 15 TO 25 KT
WITH AREAS TO NEAR 30 KT OVER ERN LAKE SUPERIOR LATE TUE AFTERNOON
AND EVENING. A DEEPER LOW PRESSURE SYSTEM MOVING INTO THE UPPER GREAT LAKES
ON THURSDAY COULD CAUSE AN INCREASE IN ERLY WINDS TO 30 KT LATE WED
NIGHT INTO THURSDAY. OTHERWISE...WINDS IN THE VICINITY OF THE LOW
SHOULD GENERALLY REMAIN LESS THAN 20 KTS WEDNESDAY THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MRD
AVIATION...VOSS
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED FOR 12Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
535 AM CDT TUE OCT 16 2012
.DISCUSSION...ISSUED 417 AM CDT
TODAY WILL BE THE LAST DAY OF ABOVE NORMAL TEMPS FOR A WHILE AS A
POWERFUL STORM SYSTEM ARRIVES ON WEDNESDAY. TEMPS WILL COOL DOWN
THURSDAY AND FRIDAY...BUT A BRIEF WARM UP IS EXPECTED FOR THE
WEEKEND AHEAD OF THE NEXT SYSTEM FORECAST TO AFFECT THE REGION
EARLY NEXT WEEK.
TODAY...MORNING IR IMAGERY WITH 500MB HEIGHTS SHOWED SOME MID
LEVEL CLOUDS AHEAD OF A SHORTWAVE ABOUT TO CROSS THE MN/DAKOTA
BORDER. ISENTROPIC LIFT AHEAD OF THIS WAVE WAS ENOUGH TO PRODUCE A
FEW SPRINKLES ACROSS CENTRAL MINNESOTA AND NORTHERN
WISCONSIN...BUT DRY AIR IN THE LOWEST 6000FT OF THE ATMOSPHERE WAS
KEEPING THE MEASURABLE RAINFALL AT BAY. AT THE SURFACE WARM AIR
ADVECTION TOGETHER WITH THE AFOREMENTIONED CLOUD DECK KEPT
OVERNIGHT LOW TEMPERATURES IN THE MID 50S ACROSS THE REGION. LATER
TODAY THE LIGHT PRECIP WILL MOVE EASTWARD...AND WINDS WILL
GRADUALLY BECOME WEST NORTHWEST AS A PRESSURE TROUGH PASSES
THROUGH. DIURNAL MIXING SHOULD BE ABLE TO TAP INTO THE H850 TEMPS
RANGING FROM 10 TO 12C...SO EXPECT HIGH TEMPS TO APPROACH 70 ACROSS
MOST OF MINNESOTA...WITH MID 60S IN WESTERN WISCONSIN WHERE CLOUDS
WILL HINDER THE DAYTIME HEATING.
WEDNESDAY THROUGH THURSDAY...AN UPPER LEVEL JET WILL CROSS THE HIGH
PLAINS AND CARVE OUT A LONG WAVE TROUGH OVER THE MIDWEST ON
WEDNESDAY. STRONG UPPER LEVEL FORCING IN THE LEFT EXIT REGION WILL
LEAD TO A BROAD AREA OF LOW PRESSURE NEAR THE MN/CANADA BORDER BY
WEDNESDAY AFTERNOON. TO THE SOUTH A COLD FRONT WILL SWEEP THROUGH
THE REGION AND FRONTOGENETICAL FORCING TOGETHER WITH THE LARGE SCALE
QG ASCENT WILL YIELD A FEW SHOWERS MOVING FROM WEST TO EAST
WEDNESDAY MORNING. THIS CYCLONE WILL QUICKLY MATURE...WITH MODELS
INDICATING A DRY SLOT ACROSS SOUTHERN MINNESOTA BY WEDNESDAY
AFTERNOON. THE DRY POST FRONTAL AIRMASS WILL EASILY MIX OUT WITH RH
VALUES FALLING INTO THE 20S ACROSS THE MINNESOTA RIVER VALLEY AMIDST
WESTERLY WINDS OF 20 TO 30 MPH. DEPENDING ON THE AMOUNT OF PRECIP
THAT FALLS EARLIER IN THE DAY...FIRE WEATHER PRODUCTS MAY BE
WARRANTED DURING THAT AFTERNOON. AS THE UPPER LEVEL JET STREAK
ROUNDS THE BAST OF THE TROUGH...THE CYCLONE WILL OCCLUDE AND BECOME
VERTICALLY STACKED BY THURSDAY. SHORTWAVES OF ENHANCED VORTICITY
WILL ROTATE AROUND THIS CUT OFF LOW AND BE THE FOCUS FOR ADDITION
ROUNDS OF PRECIPITATION. GFS 16.00 IS SLIGHTLY QUICKER THAN THE NAM
OR ECMWF...BUT ALL DEVELOP A TROWEL FEATURE WITH A MAX OF
PRECIPITATION ACROSS THE RED RIVER/MINNESOTA RIVER VALLEYS ON
THURSDAY. THEREFORE INCREASED THE POPS IN THOSE AREAS.
FRIDAY THROUGH MONDAY...BY FRIDAY THE UPPER LEVEL WAVE BEGINS TO MAKE
ITS WAY TOWARDS THE NEW ENGLAND AREA...BUT STILL EXPECT TO HAVE
OVERCAST SKIES AND COOL TEMPS WITH BRISK NORTHWEST WINDS CONTINUING
ACROSS THE REGION...AND A FEW LIGHT SHOWERS LINGERING IN EASTERN
MINNESOTA AND WISCONSIN. SWITCHING GEARS BACK TO THE LARGE
SCALE...IN THE GULF OF ALASKA...THE GEM/GFS/ECMWF 16.00 H250
FORECAST VALID FOR FRIDAY SHOWS A REMARKABLY SIMILAR JET SETTING
UP...WHICH WILL AFFECT THE REGION EARLY NEXT WEEK. TEMPORARY
RIDGING ACROSS THE CENTRAL CONUS SHOULD ALLOW SATURDAY AND SUNDAY
TO BE DRY AHEAD OF THE AFOREMENTIONED APPROACHING SYSTEM. SUNDAYS
H850 TEMPS OF 12-14C ACROSS THE REGION SHOULD GIVE WAY TO HIGH
TEMPS IN AT LEAST THE LOW TO MID 60S...SO HAVE BUMPED THESE UP
FROM THE PREVIOUS FORECAST. THERE IS SOME DISAGREEMENT BETWEEN THE
LONG RANGE MODELS IN HOW THEY HANDLE THE JET EVOLUTION...WITH THE
GFS MORE ZONAL...THE GEM MORE AMPLIFIED AND THE ECMWF IN BETWEEN
THE TWO. THEREFORE DID NOT STRAY FROM THE MODEL CONSENSUS.
&&
.AVIATION.../12Z TAF ISSUANCE/
WEAK SURFACE TROUGH IN W MN HASN`T MADE A LOT OF EWRD PROGRESS
OVERNITE AND MODELS STILL WASH IT OUT AS STRONGER TROF DEVELOPS
FARTHER WEST AHD OF UPPER TROF MOVING ACRS THE PACIFIC NW. SFC TROF
MAY MAKE IT ABT AS FAR EAST AS STC. STILL WDSRPD MID CLDS WITH BASES
GNRLY AOA 8K ACROSS AREA. MAY SEE A BRF SPRINKLE NEXT FEW HOURS AT
STC/AXN. HRRR AND GFS HAVE BEEN TRYING TO GENERATE ANOTHER AREA OF
-SHRA ACRS SC MN...AND RADAR IN LAST FEW SCANS HAS BEEN SHOWING PCPN
TRYING TO DVLP ARND MKT TO FRM. WILL PUT VCSH AT EAU 14Z-18Z. ATTM
WILL KEEP S OF MSP...BUT MAY ADJUST BEFORE ISSUE TIME IF AREA
EXPANDS NORTH.
KMSP...VFR THRU ABT NEXT 24 HRS WITH LOWERING CONDS AHEAD OF STRONG
UPPER TROF MOVING ACRS WED MRNG. IN THE SHORT TERM RADAR IS SHOWING
-SHRA DVLPG S OF MSP IN THE MKT/FRM AREA. WILL MONITOR MAY PUT IN
AT LEAST VCSH IF AREA DEVELOPS NORTH.
/OUTLOOK FOR KMSP/
WEDNESDAY...MVFR CEILINGS POSSIBLE WITH SHRA. SOUTHWEST WINDS 5 TO
15 KT SHIFTING WEST 15 TO 25 KT.
WEDNESDAY NIGHT...MVFR CEILINGS POSSIBLE LATE ALONG WITH CHANCE OF
SHRA. WEST WINDS 10 TO 20 KT.
THURSDAY AND THURSDAY NIGHT...MVFR CEILINGS EXPECTED WITH MVFR
VISIBILITY DURING SHRA. IFR CONDITIONS POSSIBLE. WEST WINDS 15 TO
25 KT WITH GUSTS ABV 30KT SHIFTING NORTHWEST.
&&
.FIRE WEATHER...
ON WEDNESDAY AFTERNOON STRONG POST FRONTAL WINDS OF 20 TO 30 MPH
LOOK TO REMAIN ON TRACK ACROSS WESTERN MINNESOTA. MEANWHILE...RH
VALUES COULD DROP INTO THE 20S ACROSS THE REGION...SPECIFICALLY
THE MINNESOTA RIVER VALLEY. DEPENDING ON AMOUNT OF PRECIPITATION
THAT FALLS DURING THE MORNING...AND THE AMOUNT OF CLEARING/DRYING
THAT TAKES PLACE DURING THE AFTERNOON...A RED FLAG WARNING MAY BE
NEEDED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JRB/BAP
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
423 PM EDT TUE OCT 16 2012
.SYNOPSIS...
SURFACE HIGH PRESSURE BUILDS INTO THE NORTH COUNTRY TONIGHT BRINGING
DECREASING CLOUDINESS AND LIGHT WINDS. THE HIGH PRESSURE AREA MOVES
EAST INTO THE GULF OF MAINE DURING WEDNESDAY AFTERNOON...AND WILL
BRING DRY WEATHER WEDNESDAY AND THURSDAY...WITH A GRADUAL
MODERATION OF TEMPERATURES. A LARGE UPPER LOW PRESSURE SYSTEM AND
ASSOCIATED OCCLUDED FRONT SHOULD BRING A PERIOD OF RAINFALL TO THE
NORTH COUNTRY THURSDAY NIGHT INTO FRIDAY MORNING.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 245 PM EDT TUESDAY...SFC RIDGE AXIS SHIFTS EWD FROM THE ERN
GREAT LAKES REGION AND CRESTS OVER THE NORTH COUNTRY OVERNIGHT.
INVERSION NEAR 3 KFT KEEPING SHALLOW STRATUS LAYER IN PLACE LATE
THIS AFTN...BUT ANTICIPATE CLEARING AREAWIDE DURING THE EVENING
HRS WITH DRYING/SUBSIDENCE. LOOKING FOR MOSTLY CLEAR SKIES FOR THE
OVERNIGHT...ALTHOUGH A FEW MID-LEVEL CLOUDS (8-12 KFT) ASSOCIATED
WITH UPSTREAM SHORTWAVE TROUGH ACROSS THE UPR MS RIVER VALLEY/WRN
GREAT LAKES REGION WILL STREAM RAPIDLY EWD AND REACH NRN NY TOWARD
09Z. HAVE INDICATED SOME SCATTERED CLOUDS IN ASSOCIATION WITH THIS
FEATURE TOWARD DAYBREAK. SHOULD BE A PERIOD OF GOOD RADIATIONAL
COOLING WITH LOW TEMPERATURES GENERALLY IN THE UPPER 20S TO LOWER
30S. NWLY GRADIENT FLOW WITH WINDS 10-20 MPH AND A FEW GUSTS TO 30
MPH WILL QUICKLY ABATE THIS EVENING WITH BOUNDARY LAYER
STABILIZATION. ANY LINGERING SPRINKLES ACROSS THE NORTHEAST
KINGDOM WILL END LATE THIS AFTN/EARLY THIS EVENING WITH
DISSIPATION OF LOW CLOUD DECK WITH NIL POPS 00-12Z.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 245 PM EDT TUESDAY...TRANQUIL WX UNTIL THURSDAY NIGHT. SFC RIDGE
AXIS DRIFTS EWD INTO THE GULF OF MAINE LATE WEDNESDAY WITH A
LIGHT 5-8 MPH SLY RETURN FLOW DEVELOPING. 850MB TEMPS MODERATE
NICELY TO +7C TO +8C BY 21Z WEDNESDAY. MID-LEVEL WAA AND
CONTINUATION OF RELATIVELY HIGH MID-LEVEL RH SUGGESTS PERIODS OF
MID-LEVEL CLOUDS DURING THE DAY WEDNESDAY. ALL IN ALL...WILL BE
PARTLY CLOUDY WITH PERIODS OF FILTERED SUN. CLOUDS SHOULDN/T
SIGNIFICANTLY IMPACT HIGH TEMPERATURES...SO STAYED CLOSE TO MOS
WITH MAX TEMPS IN THE MID-UPR 50S (OR ABOUT 10F HIGHER THAN
TUESDAY/S HIGHS).
VARIABLE MID-LEVEL CLOUDINESS CONTINUES WEDNESDAY NIGHT WITH LIGHT
SOUTH WINDS CONTINUING IN THE CHAMPLAIN VALLEY. SOME CLOUDS AND
MODIFYING AIR MASS WILL KEEP TEMPS A BIT WARMER COMPARED TO TUESDAY
NIGHT WITH LOWS WED NGT MID 30S TO LWR 40S.
THURSDAY LOOKS MILDER STILL AS MID-LEVEL HEIGHTS BUILD IN ADVANCE OF
LARGE-SCALE/SLOW-MOVING UPR LOW ACROSS THE MID-UPR MS RIVER VALLEY.
HIGHS WILL REACH THE MID-UPR 60S...WARMEST IN THE CHAMPLAIN AND ST.
LAWRENCE RIVER VALLEYS. SOUTH WINDS CONTINUE WITH SFC HIGH WELL
OFFSHORE AND VERTICALLY STACKED LOW OVER THE WRN GREAT LAKES. MAY
SEE AN INCREASE IN HIGH CLOUDS LATE IN THE DAY - ESPECIALLY ACROSS
NRN NY.
LEADING FRONTAL RAIN BAND WITH LARGE-SCALE OCCLUSION SWINGS INTO THE
FORECAST AREA DURING THURSDAY NIGHT BASED ON 12Z GFS/SREF/NAM. THE
ECMWF CONTINUES TO BE SLOWER WITH THE EVOLUTION OF THIS
SYSTEM...AND COULD SUGGEST A SLOWER PCPN ARRIVAL TIME. AT THIS
POINT...WILL INDICATE CLOUDY SKIES/LIKELY POPS WITH A STEADY
STRATIFORM RAIN DEVELOPING. QPF POTL 0.25-0.50"...THOUGH LIKELY
LESS ACROSS FAR ERN/NERN VT WITH LATER ARRIVAL TIME OF PRECIP.
WILL BE A MILD NIGHT WITH SE/SOUTH WINDS AND CLOUDS AREAWIDE. MAY
SEE SOME GUSTY DOWNSLOPE WINDS ALONG THE WESTERN SLOPES OF THE
GREEN MTNS (UP TO 35 MPH BASED ON PRESENT INDICATIONS) AND WILL BE
SOMETHING TO MONITOR AS DETAILS BECOME MORE APPARENT. SHOULD SEE
RATHER UNIFORM AND MILD LOW TEMPS EXPECTED IN THE UPR 40S TO LWR
50S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 430 PM EDT TUESDAY...FCST FOCUS WL BE EVOLUTION/MOVEMENT OF
FULL LATITUDE CLOSED MID/UPPER LVL CIRCULATION ACRS THE EASTERN
CONUS AND IMPACTS TO OUR CWA. OVERALL MODELS IN GOOD AGREEMENT
WITH LARGE SCALE CLOSED SYSTEM SHIFTING FROM THE NORTHERN PLAINS
INTO THE OHIO VALLEY BY FRIDAY AND INTO EASTERN CANADA BY THE
WEEKEND. HOWEVER...PLENTY OF UNCERTAINTY WITH REGARDS TO TIMING OF
INDIVIDUAL S/W`S AND RIBBONS OF ENHANCED 850 TO 500MB RH...WHICH
RESULTS IN UNCERTAINTY IN PRECIP TIMING/PLACEMENT FOR FRIDAY INTO
THIS UPCOMING WEEKEND. GFS/SREF/GEM AND ECMWF ALL SHOW A SURGE OF
>1.0" PWS AHEAD OF OCCLUDED TYPE BOUNDARY ON FRIDAY INTO
SATURDAY...ASSOCIATED WITH POTENT LOW/MID LVL JET...AND STRONG
ULVL DIVERGENCE. GIVEN AVAILABLE MOISTURE/DYNAMICS WL CONT TO
MENTION HIGH LIKELY POPS ATTM FOR FRIDAY INTO SAT...BUT 6 TO 10 HR
WINDOW FOR HEAVIEST QPF IS DIFFICULT TO TIME. GIVEN THE DOWNSTREAM
BLOCKING FROM WESTERN ATLANTIC MID/UPPER LVL RIDGE AND DEEP CLOSED
CUTOFF CIRCULATION...FEEL A SLOWER/WETTER AND WARMER SOLUTION OF
THE GEM/ECMWF LOOKS REASONABLE AND WL TREND TWD. THIS SUPPORTS
ABOVE NORMAL TEMPS FOR FRI THRU SAT...WITH A COOLING TREND BY
SUNDAY...AS LLVL CAA DEVELOPS BEHIND DEPARTING CLOSED CIRCULATION.
IN ADDITION...WL CONT TO MENTION CHC POPS FOR SUNDAY ASSOCIATED
WITH UPSLOPE FLW AND LLVL CAA. THIS WL PROBABLY NEED TO BE
ADJUSTED UPWARD AS CONFIDENCE INCREASES WITH REGARDS TO AMOUNT OF
MOISTURE AND UPSLOPE LIFT. MID/UPPER LVL RIDGE REDEVELOPS FOR
EARLY NEXT WEEK...WITH ABOVE NORMAL TEMPS AND SOME DRYING.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...AVIATION CHALLENGE IS TIMING OF CLOUDS
DISSIPATING ACRS OUR TAF SITES THIS AFTN/EVENING. CRNT SFC
ANALYSIS SHOWS CYCLONIC UPSLOPE FLW ACRS OUR CWA WITH LOW PRES
LOCATED EAST OF CARIBOU MAINE THIS AFTN. THIS LLVL UPSLOPE
FLW...COMBINED WITH MOISTURE TRAPPED BLW TEMP INVERSION HAS RESULTED
PLENTY OF CLOUDS WITH MVFR CONDITIONS AT MOST SITES. NAM/GFS
VERTICAL SOUNDINGS ARE TOO QUICK AT ERODING THE CLOUDS...GIVEN
MOISTURE/WIND DIRECTION...WL TREND TOWARD THE LATEST RAP
SOUNDINGS. THESE SHOW MVFR BCMG VFR CONDITIONS BY 21Z AT
PBG/BTV/RUT/MSS AND AFT 00Z AT MPV/SLK WITH NW WINDS BECMG
LIGHT/VARIABLE TWD SUNSET. INTERESTING RAP SOUNDINGS CONT TO SHOW
VERY SHALLOW RH PROFILES OVERNIGHT AT SLK/MPV...BUT THINKING WITH
SFC HIGH PRES/SUBSIDENCE DEPTH OF MOISTURE WL NOT BE ENOUGH TO
PRODUCE CLOUDS...BUT SATL TRENDS WL NEED TO BE MONITORED.
OUTLOOK 18Z WEDNESDAY THROUGH SATURDAY...
SFC HIGH PRES WITH VFR CONDITIONS PREVAIL THRU 00Z FRIDAY...BEFORE
NEXT SYSTEM PRODUCE WIDESPREAD RAIN WITH MVFR CONDITIONS BTWN 06Z
FRIDAY AND 18Z FRIDAY. IN ADDITION...SOME GUSTY SOUTH TO SOUTHEAST
WINDS WL BE POSSIBLE...ESPECIALLY AT RUT...ALONG WITH AREAS OF LLVL
WIND SHEAR AND TURBULENCE THURS NIGHT/FRIDAY MORNING. AREAS OF
SCATTERED SHOWERS WITH MVFR AND BRIEF PERIODS OF IFR AT SLK/MPV WL
BE POSSIBLE FRIDAY AFTN INTO SAT....AS SFC LOW PRES CONTS TO
IMPACT OUR TAF SITES.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...TABER
AVIATION...TABER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
252 PM EDT TUE OCT 16 2012
.SYNOPSIS...
SURFACE HIGH PRESSURE BUILDS INTO THE NORTH COUNTRY TONIGHT BRINGING
DECREASING CLOUDINESS AND LIGHT WINDS. THE HIGH PRESSURE AREA MOVES
EAST INTO THE GULF OF MAINE DURING WEDNESDAY AFTERNOON...AND WILL
BRING DRY WEATHER WEDNESDAY AND THURSDAY...WITH A GRADUAL
MODERATION OF TEMPERATURES. A LARGE UPPER LOW PRESSURE SYSTEM AND
ASSOCIATED OCCLUDED FRONT SHOULD BRING A PERIOD OF RAINFALL TO THE
NORTH COUNTRY THURSDAY NIGHT INTO FRIDAY MORNING.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 245 PM EDT TUESDAY...SFC RIDGE AXIS SHIFTS EWD FROM THE ERN
GREAT LAKES REGION AND CRESTS OVER THE NORTH COUNTRY OVERNIGHT.
INVERSION NEAR 3 KFT KEEPING SHALLOW STRATUS LAYER IN PLACE LATE
THIS AFTN...BUT ANTICIPATE CLEARING AREAWIDE DURING THE EVENING
HRS WITH DRYING/SUBSIDENCE. LOOKING FOR MOSTLY CLEAR SKIES FOR THE
OVERNIGHT...ALTHOUGH A FEW MID-LEVEL CLOUDS (8-12 KFT) ASSOCIATED
WITH UPSTREAM SHORTWAVE TROUGH ACROSS THE UPR MS RIVER VALLEY/WRN
GREAT LAKES REGION WILL STREAM RAPIDLY EWD AND REACH NRN NY TOWARD
09Z. HAVE INDICATED SOME SCATTERED CLOUDS IN ASSOCIATION WITH THIS
FEATURE TOWARD DAYBREAK. SHOULD BE A PERIOD OF GOOD RADIATIONAL
COOLING WITH LOW TEMPERATURES GENERALLY IN THE UPPER 20S TO LOWER
30S. NWLY GRADIENT FLOW WITH WINDS 10-20 MPH AND A FEW GUSTS TO 30
MPH WILL QUICKLY ABATE THIS EVENING WITH BOUNDARY LAYER
STABILIZATION. ANY LINGERING SPRINKLES ACROSS THE NORTHEAST
KINGDOM WILL END LATE THIS AFTN/EARLY THIS EVENING WITH
DISSIPATION OF LOW CLOUD DECK WITH NIL POPS 00-12Z.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 245 PM EDT TUESDAY...TRANQUIL WX UNTIL THURSDAY NIGHT. SFC RIDGE
AXIS DRIFTS EWD INTO THE GULF OF MAINE LATE WEDNESDAY WITH A
LIGHT 5-8 MPH SLY RETURN FLOW DEVELOPING. 850MB TEMPS MODERATE
NICELY TO +7C TO +8C BY 21Z WEDNESDAY. MID-LEVEL WAA AND
CONTINUATION OF RELATIVELY HIGH MID-LEVEL RH SUGGESTS PERIODS OF
MID-LEVEL CLOUDS DURING THE DAY WEDNESDAY. ALL IN ALL...WILL BE
PARTLY CLOUDY WITH PERIODS OF FILTERED SUN. CLOUDS SHOULDN/T
SIGNIFICANTLY IMPACT HIGH TEMPERATURES...SO STAYED CLOSE TO MOS
WITH MAX TEMPS IN THE MID-UPR 50S (OR ABOUT 10F HIGHER THAN
TUESDAY/S HIGHS).
VARIABLE MID-LEVEL CLOUDINESS CONTINUES WEDNESDAY NIGHT WITH LIGHT
SOUTH WINDS CONTINUING IN THE CHAMPLAIN VALLEY. SOME CLOUDS AND
MODIFYING AIR MASS WILL KEEP TEMPS A BIT WARMER COMPARED TO TUESDAY
NIGHT WITH LOWS WED NGT MID 30S TO LWR 40S.
THURSDAY LOOKS MILDER STILL AS MID-LEVEL HEIGHTS BUILD IN ADVANCE OF
LARGE-SCALE/SLOW-MOVING UPR LOW ACROSS THE MID-UPR MS RIVER VALLEY.
HIGHS WILL REACH THE MID-UPR 60S...WARMEST IN THE CHAMPLAIN AND ST.
LAWRENCE RIVER VALLEYS. SOUTH WINDS CONTINUE WITH SFC HIGH WELL
OFFSHORE AND VERTICALLY STACKED LOW OVER THE WRN GREAT LAKES. MAY
SEE AN INCREASE IN HIGH CLOUDS LATE IN THE DAY - ESPECIALLY ACROSS
NRN NY.
LEADING FRONTAL RAIN BAND WITH LARGE-SCALE OCCLUSION SWINGS INTO THE
FORECAST AREA DURING THURSDAY NIGHT BASED ON 12Z GFS/SREF/NAM. THE
ECMWF CONTINUES TO BE SLOWER WITH THE EVOLUTION OF THIS
SYSTEM...AND COULD SUGGEST A SLOWER PCPN ARRIVAL TIME. AT THIS
POINT...WILL INDICATE CLOUDY SKIES/LIKELY POPS WITH A STEADY
STRATIFORM RAIN DEVELOPING. QPF POTL 0.25-0.50"...THOUGH LIKELY
LESS ACROSS FAR ERN/NERN VT WITH LATER ARRIVAL TIME OF PRECIP.
WILL BE A MILD NIGHT WITH SE/SOUTH WINDS AND CLOUDS AREAWIDE. MAY
SEE SOME GUSTY DOWNSLOPE WINDS ALONG THE WESTERN SLOPES OF THE
GREEN MTNS (UP TO 35 MPH BASED ON PRESENT INDICATIONS) AND WILL BE
SOMETHING TO MONITOR AS DETAILS BECOME MORE APPARENT. SHOULD SEE
RATHER UNIFORM AND MILD LOW TEMPS EXPECTED IN THE UPR 40S TO LWR
50S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...A LOT OF UNCERTAINTY EXISTS IN THE
EXTENDED PORTION OF THE FORECAST DUE TO DIFFERING MODEL SOLUTIONS
IN REGARDS TO THE OVERALL SYNOPTIC PATTERN FROM THURSDAY NIGHT
ONWARDS. FORECASTER CONFIDENCE IS LOW.
RELIABLE MEDIUM/LONG TERM MODELS OF THE GFS AND ECMWF SEEM TO
CONTINUE TO BE AT ODDS WITH THE OVERALL HANDLING OF A POTENT LOW
PRESSURE SYSTEM MOVING OUT OF THE GREAT LAKES REGION THURSDAY NIGHT.
OVERALL...THERE IS A GENERAL AGREEMENT IN REGARDS TO THE TRACK FROM
THE GREAT LAKES NORTHEASTWARD THROUGH THE SAINT LAWRENCE VALLEY AND
INTO CENTRAL QUEBEC...BUT THERE ARE HUGE DIFFERENCES IN TIMING. GFS
IS MUCH MORE PROGRESSIVE MOVING THE LOW NORTH OF THE CWA BY SATURDAY
NIGHT...WHILE THE ECMWF LAGS BEHIND BY A GOOD 24 HOURS. HARD TO
PREDICT WHICH IS RIGHT AT THIS POINT...BUT HAVE LEANED TOWARDS THE
ECMWF SOLUTION BASED ON BETTER PERFORMANCE OVER THE LAST WEEK OR SO.
THAT SAID...EXPECTING TO SEE WIDESPREAD RAIN ACROSS THE REGION
DEVELOPING LATE THURSDAY NIGHT...AND CONTINUING THROUGH FRIDAY NIGHT
AS LOW PRESSURE SLOWLY SHIFTS EASTWARD THROUGH THE GREAT LAKES.
COULD BE LOOKING AT SOME DECENT RAINFALL AMOUNTS WITH A STRONG
MOISTURE FEED OFF THE SOUTHEAST COAST...AND THIS WILL NEED TO BE
MONITORED FOR POSSIBLE FLOOD POTENTIAL AS SOIL MOISTURE IS RUNNING
HIGH FROM ABOVE NORMAL PRECIP SO FAR THIS MONTH. STRONG S/SW FLOW
WILL KEEP TEMPS RATHER MILD ACROSS THE REGION WITH LOWS IN THE 50S
AND HIGHS IN THE 60S. S/SW FLOW CONTINUES ON SATURDAY WITH CONTINUED
HIGH CHANCES FOR SHOWERS AS THE LOW SHIFTS NORTHEAST THROUGH THE
SAINT LAWRENCE VALLEY AND TRACKS A COLD FRONT ACROSS THE REGION.
WINDS SHIFT TO THE W/NW POST FRONTAL PASSAGE AND CONTINUED
CLOUDINESS IS LIKELY SATURDAY NIGHT WITH AMPLE WRAP-AROUND MOISTURE
KEEPING SOME SHOWERS AROUND. BY SUNDAY MORNING...HIGH AMPLITUDE
RIDGE BEGINS TO BUILD INTO THE REGION...AND WILL DOMINATE THE NORTH
COUNTRYS WEATHER THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH
DRY AND SEASONAL CONDITIONS EXPECTED.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...AVIATION CHALLENGE IS TIMING OF CLOUDS
DISSIPATING ACRS OUR TAF SITES THIS AFTN/EVENING. CRNT SFC
ANALYSIS SHOWS CYCLONIC UPSLOPE FLW ACRS OUR CWA WITH LOW PRES
LOCATED EAST OF CARIBOU MAINE THIS AFTN. THIS LLVL UPSLOPE
FLW...COMBINED WITH MOISTURE TRAPPED BLW TEMP INVERSION HAS RESULTED
PLENTY OF CLOUDS WITH MVFR CONDITIONS AT MOST SITES. NAM/GFS
VERTICAL SOUNDINGS ARE TOO QUICK AT ERODING THE CLOUDS...GIVEN
MOISTURE/WIND DIRECTION...WL TREND TOWARD THE LATEST RAP
SOUNDINGS. THESE SHOW MVFR BCMG VFR CONDITIONS BY 21Z AT
PBG/BTV/RUT/MSS AND AFT 00Z AT MPV/SLK WITH NW WINDS BECMG
LIGHT/VARIABLE TWD SUNSET. INTERESTING RAP SOUNDINGS CONT TO SHOW
VERY SHALLOW RH PROFILES OVERNIGHT AT SLK/MPV...BUT THINKING WITH
SFC HIGH PRES/SUBSIDENCE DEPTH OF MOISTURE WL NOT BE ENOUGH TO
PRODUCE CLOUDS...BUT SATL TRENDS WL NEED TO BE MONITORED.
OUTLOOK 18Z WEDNESDAY THROUGH SATURDAY...
SFC HIGH PRES WITH VFR CONDITIONS PREVAIL THRU 00Z FRIDAY...BEFORE
NEXT SYSTEM PRODUCE WIDESPREAD RAIN WITH MVFR CONDITIONS BTWN 06Z
FRIDAY AND 18Z FRIDAY. IN ADDITION...SOME GUSTY SOUTH TO SOUTHEAST
WINDS WL BE POSSIBLE...ESPECIALLY AT RUT...ALONG WITH AREAS OF LLVL
WIND SHEAR AND TURBULENCE THURS NIGHT/FRIDAY MORNING. AREAS OF
SCATTERED SHOWERS WITH MVFR AND BRIEF PERIODS OF IFR AT SLK/MPV WL
BE POSSIBLE FRIDAY AFTN INTO SAT....AS SFC LOW PRES CONTS TO
IMPACT OUR TAF SITES.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...LAHIFF
AVIATION...TABER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
139 PM EDT TUE OCT 16 2012
.SYNOPSIS...
A COLD FRONT HAS MOVED EAST OF THE REGION. COLDER AIR FILTERING IN
BEHIND THE FRONT COMBINED WITH AN UPPER LEVEL DISTURBANCE WILL BRING
SCATTERED MOUNTAIN SNOW SHOWERS AND A FEW LIGHT RAIN SHOWERS OR
SPRINKLES TO THE VALLEYS THIS MORNING. SKIES WILL CLEAR THIS
AFTERNOON WITH HIGH PRESSURE BRINGING FAIR WEATHER TO THE NORTH
COUNTRY LATER TODAY INTO THURSDAY. A RATHER STRONG LOW PRESSURE
SYSTEM IS EXPECTED TO BRING RAIN FRIDAY INTO SATURDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1232 PM EDT TUESDAY...HAVE UPDATED THE FCST TO DELAY
CLEARING 3-4 HRS BASED ON RAP SOUNDINGS/RH PROFILES AND PREVAILING
OVERCAST ON VIS SATELLITE IMAGERY. IT APPEARS INVERSION NEAR 3 KFT
IS HOLDING FIRM...AND TRAPPING LOW STRATUS LAYER UNTIL CLOSE TO
00Z FOR MOST SECTIONS OF THE CWA. CORRESPONDINGLY...TEMPERATURES
HAVE BEEN LOWERED A FEW DEGREES FOR THIS AFTN. THE REMAINDER OF
THE FCST REMAINS UNCHANGED.
PREVIOUS FORECAST: SCATTERED SPRINKLES/SUMMIT FLURRIES CONTINUE
ACROSS THE NORTH COUNTRY UNDER MAINLY CLOUDY SKIES. A LIGHT
COATING OF SNOW NOTED ON WEATHER CAMS ABOVE 2000` IN THE NRN
ADIRONDACKS AND CENTRAL/NRN GREEN MTNS. SFC LOW NEAR THE MAINE
COAST AND TRAILING DEFORMATION BAND WILL SHIFT AWAY FROM THE NORTH
COUNTRY BY EARLY THIS AFTN. ANTICIPATE ANY REMAINING LIGHT PCPN TO
GRADUALLY END LATE THIS MORNING/EARLY THIS AFTN WITH SKIES
GRADUALLY CLEARING THIS AFTN. HIGH TEMPS GENERALLY IN THE UPR 40S
TO AROUND 50...BUT LOCALLY IN THE MID 40S IN THE NRN ADIRONDACK
REGION AND IN VERMONT IN THE 1-2KFT ELEVATIONAL BAND. MODERATELY
STRONG PRESSURE GRADIENT IN PLACE BEHIND DEEPENING SURFACE LOW
OVER NEW BRUNSWICK. WITH STEEP LOW-LEVEL LAPSE RATES IN
PLACE...LOOKING FOR NW WINDS 10-20 MPH WITH GUSTS 25-30 MPH AT
TIMES. WINDS WILL ABATE TOWARD THIS EVENING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH THURSDAY/...
AS OF 421 AM EDT TUESDAY...GENERALLY QUIET WEATHER THROUGH THE
PERIOD. SURFACE RIDGE CRESTS OVER THE NORTH COUNTRY TONIGHT WITH
MAINLY CLEAR SKIES EXPECTED. PATCHY FOG POSSIBLE AFTER MIDNIGHT IN
THE FAVORED VERMONT RIVER VALLEYS. LOWS RANGING FROM THE MID AND
UPPER 20S IN THE ADIRONDACKS AND NORTH CENTRAL/NORTHEAST VERMONT TO
THE LOWER AND MID 30S ELSEWHERE. RIDGE AXIS SHIFTS TO THE EAST
DURING THE DAY WEDNESDAY WITH LIGHT SOUTH WINDS DEVELOPING. THIS
WILL ALLOW AIR MASS TO MODERATE SOME ALLOWING FOR HIGH TEMPERATURES
TO REACH THE LOWER 60S IN THE VALLEYS. SKIES WILL BE PARTLY TO MOSTLY
SUNNY WITH SOME MID LEVEL CLOUDS DUE A WEAK DISTURBANCE IN THE FLOW
ALOFT. CONTINUED QUIET WEDNESDAY NIGHT WITH LIGHT SOUTH WINDS IN THE
CHAMPLAIN VALLEY. NOT AS COOL WITH LOWS IN THE LOW TO MID 40S IN
THE CHAMPLAIN AND SAINT LAWRENCE VALLEYS AND 30S ELSEWHERE. HIGH
PRESSURE WILL REMAIN ALONG THE EAST COAST THURSDAY...WHILE LARGE
SCALE LOW PRESSURE SYSTEM APPROACHES FROM THE WESTERN GREAT LAKES
REGION. EXPECT SUN TO GIVE WAY TO INCREASING CLOUDS. IT SHOULD
REMAIN DRY THROUGH THE DAYLIGHT HOURS...WITH JUST A LOW CHANCE OF
SHOWERS LATE IN THE DAY OVER WESTERN ZONES. TEMPS ON THE MILD SIDE
ONCE AGAIN WITH HIGHS IN THE 60S WITH INCREASING SOUTHERLY BREEZES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...A LOT OF UNCERTAINTY EXISTS IN THE
EXTENDED PORTION OF THE FORECAST DUE TO DIFFERING MODEL SOLUTIONS
IN REGARDS TO THE OVERALL SYNOPTIC PATTERN FROM THURSDAY NIGHT
ONWARDS. FORECASTER CONFIDENCE IS LOW.
RELIABLE MEDIUM/LONG TERM MODELS OF THE GFS AND ECMWF SEEM TO
CONTINUE TO BE AT ODDS WITH THE OVERALL HANDLING OF A POTENT LOW
PRESSURE SYSTEM MOVING OUT OF THE GREAT LAKES REGION THURSDAY NIGHT.
OVERALL...THERE IS A GENERAL AGREEMENT IN REGARDS TO THE TRACK FROM
THE GREAT LAKES NORTHEASTWARD THROUGH THE SAINT LAWRENCE VALLEY AND
INTO CENTRAL QUEBEC...BUT THERE ARE HUGE DIFFERENCES IN TIMING. GFS
IS MUCH MORE PROGRESSIVE MOVING THE LOW NORTH OF THE CWA BY SATURDAY
NIGHT...WHILE THE ECMWF LAGS BEHIND BY A GOOD 24 HOURS. HARD TO
PREDICT WHICH IS RIGHT AT THIS POINT...BUT HAVE LEANED TOWARDS THE
ECMWF SOLUTION BASED ON BETTER PERFORMANCE OVER THE LAST WEEK OR SO.
THAT SAID...EXPECTING TO SEE WIDESPREAD RAIN ACROSS THE REGION
DEVELOPING LATE THURSDAY NIGHT...AND CONTINUING THROUGH FRIDAY NIGHT
AS LOW PRESSURE SLOWLY SHIFTS EASTWARD THROUGH THE GREAT LAKES.
COULD BE LOOKING AT SOME DECENT RAINFALL AMOUNTS WITH A STRONG
MOISTURE FEED OFF THE SOUTHEAST COAST...AND THIS WILL NEED TO BE
MONITORED FOR POSSIBLE FLOOD POTENTIAL AS SOIL MOISTURE IS RUNNING
HIGH FROM ABOVE NORMAL PRECIP SO FAR THIS MONTH. STRONG S/SW FLOW
WILL KEEP TEMPS RATHER MILD ACROSS THE REGION WITH LOWS IN THE 50S
AND HIGHS IN THE 60S. S/SW FLOW CONTINUES ON SATURDAY WITH CONTINUED
HIGH CHANCES FOR SHOWERS AS THE LOW SHIFTS NORTHEAST THROUGH THE
SAINT LAWRENCE VALLEY AND TRACKS A COLD FRONT ACROSS THE REGION.
WINDS SHIFT TO THE W/NW POST FRONTAL PASSAGE AND CONTINUED
CLOUDINESS IS LIKELY SATURDAY NIGHT WITH AMPLE WRAP-AROUND MOISTURE
KEEPING SOME SHOWERS AROUND. BY SUNDAY MORNING...HIGH AMPLITUDE
RIDGE BEGINS TO BUILD INTO THE REGION...AND WILL DOMINATE THE NORTH
COUNTRYS WEATHER THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH
DRY AND SEASONAL CONDITIONS EXPECTED.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...AVIATION CHALLENGE IS TIMING OF CLOUDS
DISSIPATING ACRS OUR TAF SITES THIS AFTN/EVENING. CRNT SFC
ANALYSIS SHOWS CYCLONIC UPSLOPE FLW ACRS OUR CWA WITH LOW PRES
LOCATED EAST OF CARIBOU MAINE THIS AFTN. THIS LLVL UPSLOPE
FLW...COMBINED WITH MOISTURE TRAPPED BLW TEMP INVERSION HAS RESULTED
PLENTY OF CLOUDS WITH MVFR CONDITIONS AT MOST SITES. NAM/GFS
VERTICAL SOUNDINGS ARE TOO QUICK AT ERODING THE CLOUDS...GIVEN
MOISTURE/WIND DIRECTION...WL TREND TOWARD THE LATEST RAP
SOUNDINGS. THESE SHOW MVFR BCMG VFR CONDITIONS BY 21Z AT
PBG/BTV/RUT/MSS AND AFT 00Z AT MPV/SLK WITH NW WINDS BECMG
LIGHT/VARIABLE TWD SUNSET. INTERESTING RAP SOUNDINGS CONT TO SHOW
VERY SHALLOW RH PROFILES OVERNIGHT AT SLK/MPV...BUT THINKING WITH
SFC HIGH PRES/SUBSIDENCE DEPTH OF MOISTURE WL NOT BE ENOUGH TO
PRODUCE CLOUDS...BUT SATL TRENDS WL NEED TO BE MONITORED.
OUTLOOK 18Z WEDNESDAY THROUGH SATURDAY...
SFC HIGH PRES WITH VFR CONDITIONS PREVAIL THRU 00Z FRIDAY...BEFORE
NEXT SYSTEM PRODUCE WIDESPREAD RAIN WITH MVFR CONDITIONS BTWN 06Z
FRIDAY AND 18Z FRIDAY. IN ADDITION...SOME GUSTY SOUTH TO SOUTHEAST
WINDS WL BE POSSIBLE...ESPECIALLY AT RUT...ALONG WITH AREAS OF LLVL
WIND SHEAR AND TURBULENCE THURS NIGHT/FRIDAY MORNING. AREAS OF
SCATTERED SHOWERS WITH MVFR AND BRIEF PERIODS OF IFR AT SLK/MPV WL
BE POSSIBLE FRIDAY AFTN INTO SAT....AS SFC LOW PRES CONTS TO
IMPACT OUR TAF SITES.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...BANACOS
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...TABER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1235 PM EDT TUE OCT 16 2012
.SYNOPSIS...
A COLD FRONT HAS MOVED EAST OF THE REGION. COLDER AIR FILTERING IN
BEHIND THE FRONT COMBINED WITH AN UPPER LEVEL DISTURBANCE WILL BRING
SCATTERED MOUNTAIN SNOW SHOWERS AND A FEW LIGHT RAIN SHOWERS OR
SPRINKLES TO THE VALLEYS THIS MORNING. SKIES WILL CLEAR THIS
AFTERNOON WITH HIGH PRESSURE BRINGING FAIR WEATHER TO THE NORTH
COUNTRY LATER TODAY INTO THURSDAY. A RATHER STRONG LOW PRESSURE
SYSTEM IS EXPECTED TO BRING RAIN FRIDAY INTO SATURDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1232 PM EDT TUESDAY...HAVE UPDATED THE FCST TO DELAY
CLEARING 3-4 HRS BASED ON RAP SOUNDINGS/RH PROFILES AND PREVAILING
OVERCAST ON VIS SATELLITE IMAGERY. IT APPEARS INVERSION NEAR 3 KFT
IS HOLDING FIRM...AND TRAPPING LOW STRATUS LAYER UNTIL CLOSE TO
00Z FOR MOST SECTIONS OF THE CWA. CORRESPONDINGLY...TEMPERATURES
HAVE BEEN LOWERED A FEW DEGREES FOR THIS AFTN. THE REMAINDER OF
THE FCST REMAINS UNCHANGED.
PREVIOUS FORECAST: SCATTERED SPRINKLES/SUMMIT FLURRIES CONTINUE
ACROSS THE NORTH COUNTRY UNDER MAINLY CLOUDY SKIES. A LIGHT
COATING OF SNOW NOTED ON WEATHER CAMS ABOVE 2000` IN THE NRN
ADIRONDACKS AND CENTRAL/NRN GREEN MTNS. SFC LOW NEAR THE MAINE
COAST AND TRAILING DEFORMATION BAND WILL SHIFT AWAY FROM THE NORTH
COUNTRY BY EARLY THIS AFTN. ANTICIPATE ANY REMAINING LIGHT PCPN TO
GRADUALLY END LATE THIS MORNING/EARLY THIS AFTN WITH SKIES
GRADUALLY CLEARING THIS AFTN. HIGH TEMPS GENERALLY IN THE UPR 40S
TO AROUND 50...BUT LOCALLY IN THE MID 40S IN THE NRN ADIRONDACK
REGION AND IN VERMONT IN THE 1-2KFT ELEVATIONAL BAND. MODERATELY
STRONG PRESSURE GRADIENT IN PLACE BEHIND DEEPENING SURFACE LOW
OVER NEW BRUNSWICK. WITH STEEP LOW-LEVEL LAPSE RATES IN
PLACE...LOOKING FOR NW WINDS 10-20 MPH WITH GUSTS 25-30 MPH AT
TIMES. WINDS WILL ABATE TOWARD THIS EVENING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH THURSDAY/...
AS OF 421 AM EDT TUESDAY...GENERALLY QUIET WEATHER THROUGH THE
PERIOD. SURFACE RIDGE CRESTS OVER THE NORTH COUNTRY TONIGHT WITH
MAINLY CLEAR SKIES EXPECTED. PATCHY FOG POSSIBLE AFTER MIDNIGHT IN
THE FAVORED VERMONT RIVER VALLEYS. LOWS RANGING FROM THE MID AND
UPPER 20S IN THE ADIRONDACKS AND NORTH CENTRAL/NORTHEAST VERMONT TO
THE LOWER AND MID 30S ELSEWHERE. RIDGE AXIS SHIFTS TO THE EAST
DURING THE DAY WEDNESDAY WITH LIGHT SOUTH WINDS DEVELOPING. THIS
WILL ALLOW AIR MASS TO MODERATE SOME ALLOWING FOR HIGH TEMPERATURES
TO REACH THE LOWER 60S IN THE VALLEYS. SKIES WILL BE PARTLY TO MOSTLY
SUNNY WITH SOME MID LEVEL CLOUDS DUE A WEAK DISTURBANCE IN THE FLOW
ALOFT. CONTINUED QUIET WEDNESDAY NIGHT WITH LIGHT SOUTH WINDS IN THE
CHAMPLAIN VALLEY. NOT AS COOL WITH LOWS IN THE LOW TO MID 40S IN
THE CHAMPLAIN AND SAINT LAWRENCE VALLEYS AND 30S ELSEWHERE. HIGH
PRESSURE WILL REMAIN ALONG THE EAST COAST THURSDAY...WHILE LARGE
SCALE LOW PRESSURE SYSTEM APPROACHES FROM THE WESTERN GREAT LAKES
REGION. EXPECT SUN TO GIVE WAY TO INCREASING CLOUDS. IT SHOULD
REMAIN DRY THROUGH THE DAYLIGHT HOURS...WITH JUST A LOW CHANCE OF
SHOWERS LATE IN THE DAY OVER WESTERN ZONES. TEMPS ON THE MILD SIDE
ONCE AGAIN WITH HIGHS IN THE 60S WITH INCREASING SOUTHERLY BREEZES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...A LOT OF UNCERTAINTY EXISTS IN THE
EXTENDED PORTION OF THE FORECAST DUE TO DIFFERING MODEL SOLUTIONS
IN REGARDS TO THE OVERALL SYNOPTIC PATTERN FROM THURSDAY NIGHT
ONWARDS. FORECASTER CONFIDENCE IS LOW.
RELIABLE MEDIUM/LONG TERM MODELS OF THE GFS AND ECMWF SEEM TO
CONTINUE TO BE AT ODDS WITH THE OVERALL HANDLING OF A POTENT LOW
PRESSURE SYSTEM MOVING OUT OF THE GREAT LAKES REGION THURSDAY NIGHT.
OVERALL...THERE IS A GENERAL AGREEMENT IN REGARDS TO THE TRACK FROM
THE GREAT LAKES NORTHEASTWARD THROUGH THE SAINT LAWRENCE VALLEY AND
INTO CENTRAL QUEBEC...BUT THERE ARE HUGE DIFFERENCES IN TIMING. GFS
IS MUCH MORE PROGRESSIVE MOVING THE LOW NORTH OF THE CWA BY SATURDAY
NIGHT...WHILE THE ECMWF LAGS BEHIND BY A GOOD 24 HOURS. HARD TO
PREDICT WHICH IS RIGHT AT THIS POINT...BUT HAVE LEANED TOWARDS THE
ECMWF SOLUTION BASED ON BETTER PERFORMANCE OVER THE LAST WEEK OR SO.
THAT SAID...EXPECTING TO SEE WIDESPREAD RAIN ACROSS THE REGION
DEVELOPING LATE THURSDAY NIGHT...AND CONTINUING THROUGH FRIDAY NIGHT
AS LOW PRESSURE SLOWLY SHIFTS EASTWARD THROUGH THE GREAT LAKES.
COULD BE LOOKING AT SOME DECENT RAINFALL AMOUNTS WITH A STRONG
MOISTURE FEED OFF THE SOUTHEAST COAST...AND THIS WILL NEED TO BE
MONITORED FOR POSSIBLE FLOOD POTENTIAL AS SOIL MOISTURE IS RUNNING
HIGH FROM ABOVE NORMAL PRECIP SO FAR THIS MONTH. STRONG S/SW FLOW
WILL KEEP TEMPS RATHER MILD ACROSS THE REGION WITH LOWS IN THE 50S
AND HIGHS IN THE 60S. S/SW FLOW CONTINUES ON SATURDAY WITH CONTINUED
HIGH CHANCES FOR SHOWERS AS THE LOW SHIFTS NORTHEAST THROUGH THE
SAINT LAWRENCE VALLEY AND TRACKS A COLD FRONT ACROSS THE REGION.
WINDS SHIFT TO THE W/NW POST FRONTAL PASSAGE AND CONTINUED
CLOUDINESS IS LIKELY SATURDAY NIGHT WITH AMPLE WRAP-AROUND MOISTURE
KEEPING SOME SHOWERS AROUND. BY SUNDAY MORNING...HIGH AMPLITUDE
RIDGE BEGINS TO BUILD INTO THE REGION...AND WILL DOMINATE THE NORTH
COUNTRYS WEATHER THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH
DRY AND SEASONAL CONDITIONS EXPECTED.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THROUGH 12Z WEDNESDAY...A MIX OF VFR AND MVFR CONDITIONS WILL
CONTINUE THROUGH AT LEAST 18Z TODAY WITH SOME ISOLATED TO
SCATTERED RAIN/SNOW SHOWERS AROUND AS LOW PRESSURE EXITS NORTHEAST
OFF THE ATLANTIC COAST. IN ADDITION...WNW WINDS WILL CONTINUE TO BE
GUSTY IN THE 20-25 KT RANGE. AFTER 21-00Z...HIGH PRESSURE BUILDS
INTO THE REGION WITH WINDS DIMINISHING AND SKIES TRENDING TO CLEAR
FOR THE OVERNIGHT HOURS.
OUTLOOK 12Z WEDNESDAY THROUGH SATURDAY...
12Z WEDNESDAY THROUGH 00Z FRIDAY...VFR UNDER HIGH PRESSURE.
00Z FRIDAY THROUGH SATURDAY...VFR CONDITIONS TRENDING TO MVFR AND
POSSIBLY IFR IN PERIODS OF RAIN AS LOW PRESSURE MOVES ACROSS THE
REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...BANACOS
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
650 PM EDT TUE OCT 16 2012
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST ACROSS THE GREAT LAKES TONIGHT AND
WEDNESDAY. A COLD FRONT WILL SWEEP ACROSS THE AREA ON THURSDAY. AN
UPPER LOW WILL DROP SOUTHEAST ACROSS THE MIDWEST ON THURSDAY AND
CROSS THE LOCAL AREA ON FRIDAY INTO SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
INCREASING CLOUDS FOR TONIGHT AND CONTINUED THE 20 POPS. INCREASED
THE POP COVERAGE OVER NORTHWEST OHIO. THE HRRR MODEL SEEMS
OVERDONE AS PER MOST MODELS NOT INDICATING MEASURABLE. WILL
MONITOR THIS FOR THE NEXT UPDATE. AIRMASS SEEMS TO STABLE FOR
THAT. NO CHANGE TO LOWS AT THIS TIME.
SHORT WAVE ZIPPING ACROSS THE UPPER GREAT LAKES LATE THIS
AFTERNOON INTO TONIGHT. THE SHORT WAVE WILL DAMPEN OUT AS THE LONG
WAVE RIDGE BUILDS AND IT IS CHASED BY A MORE SIGNIFICANT WAVE
DIGGING INTO THE HIGH PLAINS. NONETHELESS...THERE IS A DECENT LOW
LEVEL JET AND STRONG WARM ADVECTION...ESSENTIALLY A WARM FRONT.
PRETTY COMMON FOR THESE TYPES OF SYSTEMS TO HAVE ENOUGH UPWARD
MOTION TO GET SOME DROPS TO FALL FROM A MID LEVEL CLOUD DECK.
NOTHING SIGNIFICANT...BUT A PASSING SHOWER COULD REACH THE GROUND
ESPECIALLY ACROSS THE NORTHERN COUNTIES TONIGHT.
LOWS WILL BE WARMER THAN RECENT NIGHTS AS THE SOUTH BREEZE WILL
PERSIST. QUITE A BIT OF THE TEMPERATURE DROP WILL BE THIS EVENING
AND TEMPS MIGHT EVEN RISE A DEGREE OR TWO IN THE DOWNSLOPE AND
LAKESHORE AREAS. LOWS WILL DIP TO THE MID OR UPPER 40S IN MOST
AREAS WITH LOWER 40S ACROSS THE COLD SPOTS OF NW PA.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
THE MAJORITY OF MID/HIGH CLOUDS SHOULD MOVE EAST OF THE FORECAST
AREA ON WEDNESDAY. SCATTERED CUMULUS/STRATOCUMULUS MAY DEVELOP OVER
EXTREME NE OH/NW PA...OTHERWISE WE SHOULD SEE A FAIR AMOUNT OF
SUNSHINE AND A BRISK SOUTH BREEZE. BOUNDARY LAYER MODEL
TEMPERATURES SUPPORT LOWER AND MID 70S FOR HIGHS AND SEEING THE
CURRENT TEMPERATURES TO OUR WEST IT SEEMS REASONABLE.
THE MODELS ARE GETTING CLOSE ON THEIR TIMING OF THE COLD/OCCLUDED
FRONT ON THURSDAY...ARRIVING TO NORTHWEST OHIO DURING THE EARLY
MORNING HOURS THURSDAY AND PUSHING ACROSS EXTREME NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA THURSDAY AFTERNOON. EXPECT A GENERAL
DIMINISHING IN THE SHOWERS AS THE FRONT OUT RUNS THE LOW LEVEL JET
AND ENCOUNTERS THE DOWNSLOPE SSE WIND.
SOME CONCERN FOR WIND ON THURSDAY AS THE 850 MB WIND IS PROGGED
BY MOST MODELS TO ABOUT 60 KNOTS. THE TIMING IS NOT GREAT FOR
REACHING THE MAXIMUM WIND AS THE SHOWERS WITH THE FRONT WILL
STABILIZE THE ATMOSPHERE. THERE COULD BE SOME GOOD GUSTS WITH THE
ONSET OF THE SHOWERS AND THERE WILL BE DECENT GUSTS BEHIND THE
FRONT...MOST LIKELY IN THE 35 TO 40 MPH RANGE. WE WILL HAVE TO
CONTINUE TO MONITOR. THE BOUNDARY LAYER REMAINS RATHER WARM ON
THURSDAY BUT IT IS COOLING OFF ALOFT. OFTEN WE CAN SNEAK HIGH
TEMPERATURES A COUPLE DEGREES WARMER THAN ONE WOULD THINK IN THAT
SITUATION AND WILL FORECAST HIGHS GENERALLY IN THE LOWER/MID 60S.
THE UPPER LOW WILL MOVE INTO THE AREA ON FRIDAY AND EXPECT SHOWERS
TO INCREASE. IF IT IS CLOUDY AND SHOWERY THEN TEMPERATURES
WOULD BE COOL...OR IF THERE WILL BE SOME SUNSHINE AND THE SHOWERS
DEVELOP CONVECTIVELY...IT COULD BE WARMER. WILL BE CONSERVATIVE AND
STAY ON THE COOL SIDE AT THIS TIME...WITH FORECAST HIGHS IN THE
50S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
UPPER TROUGH OVER THE AREA ON SATURDAY WILL ALLOW FOR CONTINUED
CLOUDS AND LIKELY LAKE EFFECT SHOWERS ACROSS FAR NE OH AND NW PA.
THIS TROUGH WILL QUICKLY MOVE TO THE EAST THROUGH SATURDAY NIGHT
WITH RIDGING DEVELOPING OVER THE AREA FOR SUNDAY. COOLER TEMPS
EXPECTED ON SATURDAY WITH THE TROUGH...BUT QUICKLY REBOUNDING ON
SUNDAY WITH READINGS CLIMBING BACK WELL INTO THE 60S FOR THE WEST
AND NEAR 60 FOR THE EAST. HIGH PRESSURE SLIDES OFF TO THE EAST
MONDAY WITH DEVELOPING SOUTH FLOW AND WARM AIR ADVECTION ACROSS THE
AREA.
MODELS CONTINUING TO MAKE CHANGES FOR THE NEXT FRONTAL PASSAGE AT
THE VERY END OF THE PERIOD...WITH LATEST 12Z ECMWF CLOSER TO THE
GFS. FOR NOW ADDED IN POPS MONDAY NIGHT ACROSS THE NORTHERN HALF OF
THE AREA WITH MILD OVERNIGHT TEMPS AHEAD OF THE FRONT.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
LOWER CLOUDS DISSIPATING ACROSS EASTERN SITES FROM ERI-YNG EARLY
THIS AFTERNOON. VFR CONDITIONS EXPECTED THROUGH TONIGHT AS A WARM
FRONT APPROACHING THE AREA. MID CLOUDS ARE EXPECTED TO BUILD
ACROSS WESTERN SITES AFTER MIDNIGHT AND BUILD EASTWARD OVERNIGHT.
THERE IS THE CHANCE FOR SOME SPRINKLES BETWEEN 07-12Z ACROSS
WESTERN SITES TO NEAR CLE...BUT CONFIDENCE LOW AT THIS POINT AND
WILL NOT INCLUDE IN TAF FORECASTS. WARM FRONT WILL PUSH NORTH OF
LAKE ERIE WED MORNING ALLOWING FOR CLEARING SKIES...BUT SOUTH
WINDS WILL INCREASE QUICKLY IN THE MORNING AND BECOME GUSTY BY
MIDDAY.
.OUTLOOK...NON VFR DEVELOPING THURSDAY/THURSDAY NIGHT IN SHOWERS
ASSOCIATED WITH THE NEXT COLD FRONT. NON VFR LINGERING AT TIMES ON
FRIDAY AND SATURDAY AS A TROUGH OF LOW PRESSURE REMAINS OVER THE
GREAT LAKES.
&&
.MARINE...
HIGH PRESSURE OVER THE REGION WILL BUILD TO THE EAST COAST ON
WEDNESDAY. THIS WILL ALLOW SOUTHERLY WINDS TO INCREASE AHEAD OF THE
NEXT LOW PRESSURE SYSTEM. WINDS WILL INCREASE TO 20 TO 25 KNOTS FOR
A PERIOD OF TIME...VEERING TO SOUTHWEST BEHIND THE PASSAGE OF A COLD
FRONT. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR A PERIOD OF
TIME ON THURSDAY.
THIS BROAD AREA OF LOW PRESSURE WILL SLOWLY DRIFT EAST ACROSS THE
REGION THROUGH THE END OF THE WEEK. HIGH PRESSURE WILL BUILD OVER
THE OHIO VALLEY ON SATURDAY WITH DECREASING WINDS AND WAVES.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KIELTYKA/KOSARIK
SHORT TERM...KOSARIK
LONG TERM...ABE
AVIATION...ABE
MARINE...KEC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
122 AM EDT TUE OCT 16 2012
.SYNOPSIS...
A COLD FRONT OVER FAR EASTERN PENNSYLVANIA THIS EVENING WILL EXIT
OFF THE MID ATLANTIC COAST OVERNIGHT. MAINLY DRY AND MILD WEATHER
WILL FOLLOW FOR THE MID-WEEK PERIOD. A DEEP UPPER LEVEL LOW WILL
DEVELOP OVER THE UPPER PLAINS AND MIDWEST OVER THE NEXT FEW DAYS.
THE DEEP LOW WILL THEN MOVE TO THE EAST AND PUSH A COLD FRONT
THROUGH LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SFC COLD FRONT IS APPROACHING THE NEW JERSEY COAST...AND NW FLOW
IN THE LOWEST 5-6 KFT HAS SPREAD ACROSS ALL OF THE CWA IN ITS
WAKE. STRONG BACKING TO THE FLOW WAS SEEN ACROSS THE EASTERN
2/3RDS OF THE CWA /IN THE MID AND UPPER LEVELS/ AS A SHARPENING
UPPER TROUGH DRIFTS RIGHT OVERHEAD LATE TONIGHT.
LAST VESTIGES OF RAIN WAS BRUSHING SERN YORK AND LANCASTER
COUNTIES ATTM...IN ASSOCIATION WITH UVVEL BENEATH THE FAVORABLE
RIGHT ENTRANCE REGION OF STRONG UPPER JET. SOME PARTIAL CLEARING
WILL OCCUR ACROSS THE SUSQ VALLEY THANKS TO DEEPENING SUBSIDENCE
AS THE LEFT ENTRANCE REGION OF THE 115 KT UPPER JET DRAGS ACROSS
THAT REGION.
FURTHER WEST...STRONG MID LEVEL /700-500MB/ COLD ADVECTION AND A
POCKET OF STEEP 850-700 MB LAPSE RATES WAS SUPPORTING SCATTERED
LIGHT SHOWERS ACROSS THE WESTERN MTNS AND LAUREL HIGHLANDS.
LATEST HRRR GUIDANCE SHOWS THIS AREA OF SHOWERS DISSOLVING QUICKLY
OVER THE NEXT FW HOURS AND BECOMING CONFINED TO THE FAR NW ZONES
THROUGH ABOUT 06-07Z.
ADDITIONAL RAINFALL AMOUNTS IN ANY OF THESE AFOREMENTIONED AREAS OF
SHOWERS WILL BE 0.05 OR LESS.
THIS POCKET OF COLD AIR ALOFT WITH 700 MB TEMPS INITIALLY AROUND
-8C EARLY THIS EVENING...WILL GRADUALLY FILL/WARM BY 3-4C AS IT
CROSSES CENTRAL PENN...AND REACHES THE SUSQ VALLEY LATE TONIGHT.
OTHERWISE...SHALLOW MOISTURE TRAPPED BENEATH THE LOWERING
SUBSIDENCE INVERSION BASE WILL KEEP SKIES MOSTLY CLOUDY TO CLOUDY
ACROSS THE NRN AND WRN MTNS...WITH VARYING AMOUNTS OF STRATO CU
ACROSS THE SE HALF OF THE FCST AREA.
TEMPS ON TRACK TO ACHIEVE LOWS RIGHT AROUND NORMAL EARLY TUESDAY...
RANGING FROM THE M-U30S ACROSS THE NW...TO THE M40S IN THE SE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
ANY ISOLD SHRA IN THE NW SHOULD BE DONE AROUND SUNRISE TUES...SO
WILL KEEP POPS NIL AREA WIDE FOR THE DAYTIME. DAYTIME TEMPS WILL
REMAIN VERY CLOSE TO SEASONAL NORMALS...TOPPING OUT IN THE M50S-
M60S. RIDGE AXIS STILL OFF TO THE WEST IN THE MORNING...BUT
OVERHEAD LATE IN THE DAY...SO WINDS SHOULD BEGIN 8-10KTS AND COULD
INCREASE/GUST A LITTLE BUT THEN LIGHTEN UP - ESP IN THE W -
THROUGH THE AFTN. AN UNEVENTFUL BUT TYPICAL AUTUMN DAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
SFC HIGH PRESSURE RIDGE OVER THE REGION FOR MIDWEEK WITH WESTERLY
FLOW TURNING SW ALOFT AHEAD OF DEVELOPING TROUGH. SO DRY WEATHER
WILL PREVAIL TUE NIGHT INTO THU. CHILLY NIGHT TUE NIGHT WITH LOWS IN
THE 30S...BUT RETURN FLOW ON BACK SIDE OF HIGH WILL PUSH TEMPS
SLIGHTLY ABOVE NORMAL ON WED. MILDER NIGHT WED NIGHT...THEN
INCREASING CLOUD COVER WILL BRING SEASONAL TEMPS FOR THU.
TROUGH EDGES TOWARD PA LATE WEEK...WITH FRONT RUNNING OUT AHEAD OF
SYSTEM FOR THU NIGHT/FRI BRINGING BEST CHANCE FOR WIDESPREAD RAIN
THIS WEEK. EASTERN SECTIONS COULD SEE HIGHEST AMOUNTS...WITH QPF
AROUND 0.25 INCHES...POSS UP TO 0.75 INCHES ON EASTERN EDGE.
UNFORTUNATELY...MODELS REMAIN STEADFAST IN THEIR DIFFERENCES THIS
WEEKEND WITH GFS REMAINING WEAKER AND MORE PROGRESSIVE WHILE THE
ECMWF STICKS WITH A LARGER AND SLOWER MOVING LOW. SO FORECAST
CONTINUES TO TRY TO MITIGATE THESE DIFFERENCES INTO A COMPROMISE
SOLUTION. AFTER BEST RAIN CHANCES CENTERED ON FRIDAY...KEPT SCT
SHOWERS POSS INTO THE WEEKEND WITH DRYING TREND LATE. TEMPS DO
COOL OFF A BIT OVER THE WEEKEND INTO EARLY NEXT WEEK...BUT REMAIN
CLOSE TO SEASONAL AVERAGES.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
COLD FRONT CONTINUES TO PUSHES EASTWARD OVER NIGHT AS DOWNSLOPING
WESTERLY FLOW ADVECTS IN IT/S WAKE. THIS FLOW SHOULD PRODUCE A PARTIAL
CLEARING ACROSS THE SUSQ VALLEY. RESIDUAL LOW LVL MOISTURE
ASCENDING THE W MTNS WILL PRODUCE PERSISTENT MVFR STRATO-CU AT
BFD AND IFR AT JST OVERNIGHT. SREF DATA MAKES IT POSSIBLE THAT
LIFR COULD EVEN BE PRESENT AT JST BETWEEN 09-14Z.
WHERE SKIES REMAIN CLOUDY...ATMOS WILL REMAIN WELL MIXED AND FAVOR
FREQUENT WIND GUSTS TO NEAR 20KTS OVERNIGHT ACROSS THE W MTNS.
DOWNSLOPING FLOW EAST OF THE MTNS WILL RESULT IN BRKS IN THE
OVERCAST...SOME RAD COOLING AND LIGHTER WIND SPEEDS.
SOME EARLY LOW CIGS ARE POSSIBLE TO START TUESDAY AT JST OR BFD.
HOWEVER...HIGH PRES BUILDING INTO THE STATE SUPPORTS A HIGH
CONFIDENCE FCST OF VFR CONDS EVERYWHERE BY MIDDAY.
OUTLOOK...
WED...NO SIG WX EXPECTED.
THU...AM LOW CIGS POSSIBLE EAST. PM SHRA/LOW CIGS POSS...MAINLY BFD.
FRI...SHRA/LOW CIGS POSSIBLE...ESP EARLY.
SAT...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
926 PM CDT WED OCT 17 2012
.UPDATE...CLEARING MO AND NORTHEAST AR COUNTIES FORM TOR WATCH
667.
&&
.PREV DISCUSSION... /ISSUED 850 PM CDT WED OCT 17 2012/
UPDATE...FOR SVR WATCH 671.
PREV DISCUSSION... /ISSUED 836 PM CDT WED OCT 17 2012/
UPDATE...ADDED 2 MS COUNTIES TO TOR WATCH #667
PREV DISCUSSION... /ISSUED 826 PM CDT WED OCT 17 2012/
UPDATE...UPDATE FOR TORNADO WATCH #670.
PREV DISCUSSION... /ISSUED 601 PM CDT WED OCT 17 2012/
DISCUSSION... /ISSUED 234 PM CDT WED OCT 17 2012/
CURRENT CONDITIONS ARE FOR NOW QUITE TRANQUIL ACROSS THE MIDSOUTH
WITH DEWPOINTS SLOWLY RISING ON STRONG SOUTHERLY BREEZES.
TEMPERATURES WERE IN THE 70S WITH SUNNY TO MOSTLY SUNNY SKIES.
LATEST COLD FRONT LOCATION WAS ELONGATED FROM SOUTHWEST MISSOURI
TO JUST EAST OF DALLAS TEXAS WITH CONVECTION INITIATION JUST WEST
OF SPRINGFIELD. LATEST 18Z LZK SOUNDING SHOWING A STOUT CAP OF 5C
AT 810MB...JUST ABOVE THE STRATUS DECK. CHANCES ARE THAT IT WILL
BE LATER THIS AFTERNOON FOR CONVECTION INITIATION. WILL BE
INTERESTING TO ALSO SEE AND COMPARE THIS SOUNDING TO A 19Z
RESEARCH SOUNDING LAUNCH IN EASTERN ARKANSAS WHERE SKIES WERE
MOSTLY SUNNY.
FOR TONIGHT...SEVERE WEATHER IS STILL LIKELY AS BOTH A STRONG
SHORTWAVE OVER THE CENTRAL PLAINS AND ASSOCIATED COLD FRONT SWING
THROUGH THE MISSISSIPPI VALLEY. 12Z MODEL RUNS ARE IN VERY GOOD
AGREEMENT THAT THE BRUNT OF PRECIPITATION AND SEVERE WEATHER WILL
OCCUR BETWEEN 23-06Z...WITH A HALF TO PERHAPS ONE HALF INCHES OF
TOTAL RAINFALL. AFTER SCANNING SPC`S HHR MODEL... CONVECTION WILL
REMAIN ALONG THE COLD FRONT IN NORTHWEST ARKANSAS AND SOUTHERN
MISSOURI THROUGH THE AFTERNOON HOURS...WITH A PREFRONTAL TROUGH
DEVELOPING AND SPARKING OFF CONVECTION ALONG CROWLEY`S RIDGE BY 6PM.
WIDSPREAD STRATUS CLOUD COVER OVER WESTERN AND CENTRAL ARKANSAS MAY
BE THE REASON FOR THE GREATER FOCUS TO SHIFT TO THE PRE-FRONTAL
TROUGH. BOTH BOUNDARIES ARE EXPECTED TO COMPLETELY MERGE ALONG THE
TENNESSEE RIVER BY MIDNIGHT. STRAIGHT-LINE WINDS WITH STORMS REMAINS
THE GREATEST SEVERE THREAT AS STORM/LINE SPEEDS ARE EXPECTED TO
EXCEED 50 MPH. MOST LOCATIONS WILL SEE DEWPOINTS CLIMB INTO THE
UPPER 50S AND LOW 60S AHEAD OF THE FRONT...WITH MID AND UPPER 60S
MAKING THERE WAY INTO THE SOUTHWEST DELTA COUNTIES. STILL FEEL THAT
THIS LOCATION...THAT IS SOUTH OF I-40 AND WEST OF I-55...WILL HAVE
THE BEST CHANCE FOR A TORNADIC STORM BEFORE 02Z...AND TO A LESSER
DEGREE FURTHER NORTH AND EAST. BY 02Z STORMS WILL HAVE CROSSED INTO
WEST TENNESSEE AND INTO NORTH CENTRAL MISSISSIPPI...QUICKLY EVOLVING
INTO ONE LONG LINE OF INDIVIDUAL BOWING SEGMENTS. THIS BOUNDARY
MERGER/TRANSITION IS IN RESPONSE TO A 80KT 500MB JET CROSSING
ARKANSAS. THUS A BETTER CHANCE FOR WIND DAMAGE WILL EXIST DURING THE
MID TO LATE EVENING HOURS. MODELS INDICATE THAT CONVECTION WILL EXIT
THE MIDSOUTH BY 1AM WITH SURFACE WINDS VEERING MORE WEST
SOUTHWESTERLY. LOWS WILL FALL INTO THE UPPER 40S OVER THE NORTHWEST
COUNTIES WHERE CLEARER SKIES WILL EXIST BEFORE SUNRISE...50S WILL BE
SEEN ELSEWHERE.
THURSDAY THROUGH SATURDAY...A STRONG WEST TO NORTHWEST UPPER FLOW
WILL DOMINATE THE REGION AS A CLOSED UPPER LOW PIVOTS THROUGH THE
SOUTHERN GREAT LAKES. CLOSER TO THE SURFACE HIGH PRESSURE WILL
BUILD EASTWARD FROM THE PLAIN STATES. WEST SOUTHWESTERLY SURFACE
WINDS WILL BECOME GUSTY AGAIN TOMORROW...SO THE NEED FOR ANOTHER
WIND ADVISORY WILL NEED TO BE ACCESSED BY THE NIGHTCREW. WEAK CAA
WILL CONTINUE ON FRIDAY AND SATURDAY AS WINDS SHIFT MORE
NORTHWESTERLY. NONE-THE-LESS THE BEGINNING OF THE WEEKEND WILL BE
NICE.
SUNDAY AND MONDAY...A QUICK WARMING TREND IS ANTICIPATED AS THE
LOW LEVEL FLOW TURNS SOUTHERLY AND AN UPPER RIDGE BUILDS OVER THE
EASTERN HALF OF THE U.S. THE GFS AND EURO SHOW THE PRESENCE OF A
WEAK SHORTWAVE CLIPPING THE REGION SUNDAY NIGHT AND ON MONDAY AS
IT APPROACHES THE RIDGE AXIS. HAVE ADJUSTED A SLIGHT CHANCE FOR
RAIN UP 12 HOURS TO REFLECT THIS NEW TIMING BEGINNING SUNDAY
NIGHT. HIGHS WILL RANGE FROM FIVE TO TEN DEGREES ABOVE NORMAL.
EXTENDED PERIOD...MOSTLY DRY WEATHER AND ABOVE NORMAL
TEMPERATURES WILL PERSIST INTO THE MIDDLE OF NEXT WEEK WITH
SOUTHERLY WINDS KEEPING A FRONT STATIONARY ACROSS THE MID
MISSISSIPPI VALLEY.
JAB
AVIATION...
00Z TAF SET
NOT MUCH CHANGE FROM PREVIOUS TAF SET. SHRAS/TSRAS BEGINNING TO
DEVELOP OVER EASTERN ARKANSAS WHICH IS WHAT LATEST HRRR MODEL WAS
SHOWING. BEST TIMING FOR KMEM WILL BE BETWEEN 01-04Z...FOR KJBR
00-03Z...FOR KMKL 02-05Z...AND FOR KTUP 03-06Z. LOW CIGS AND VSBYS
WILL OCCUR WITH THE SHRAS/TSRAS. WINDS WILL SWITCH AROUND TO THE
NW BRIEFLY BEHIND THE LINE BEFORE GOING BACK TO THE WSW. SPEEDS
WILL INCREASE TO 15-20 KTS SUSTAINED BETWEEN 15-18Z. GUSTS WILL BE
BETWEEN 25-30 KTS.
KRM
AVIATION...
AVIATION...
AVIATION...
&&
.AVIATION...
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 53 72 49 69 / 90 10 10 10
MKL 50 71 45 65 / 90 10 10 10
JBR 48 71 47 66 / 70 10 10 10
TUP 55 73 45 70 / 90 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR DUNKLIN-PEMISCOT.
MS...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR BENTON MS-COAHOMA-
DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-TALLAHATCHIE-TATE-
TUNICA-YALOBUSHA.
TN...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CARROLL-CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-HENDERSON-
HENRY-LAKE-LAUDERDALE-MADISON-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
850 PM CDT WED OCT 17 2012
.UPDATE...FOR SVR WATCH 671.
&&
.PREV DISCUSSION... /ISSUED 836 PM CDT WED OCT 17 2012/
UPDATE...ADDED 2 MS COUNTIES TO TOR WATCH #667
PREV DISCUSSION... /ISSUED 826 PM CDT WED OCT 17 2012/
UPDATE...UPDATE FOR TORNADO WATCH #670.
PREV DISCUSSION... /ISSUED 601 PM CDT WED OCT 17 2012/
DISCUSSION... /ISSUED 234 PM CDT WED OCT 17 2012/
CURRENT CONDITIONS ARE FOR NOW QUITE TRANQUIL ACROSS THE MIDSOUTH
WITH DEWPOINTS SLOWLY RISING ON STRONG SOUTHERLY BREEZES.
TEMPERATURES WERE IN THE 70S WITH SUNNY TO MOSTLY SUNNY SKIES.
LATEST COLD FRONT LOCATION WAS ELONGATED FROM SOUTHWEST MISSOURI
TO JUST EAST OF DALLAS TEXAS WITH CONVECTION INITIATION JUST WEST
OF SPRINGFIELD. LATEST 18Z LZK SOUNDING SHOWING A STOUT CAP OF 5C
AT 810MB...JUST ABOVE THE STRATUS DECK. CHANCES ARE THAT IT WILL
BE LATER THIS AFTERNOON FOR CONVECTION INITIATION. WILL BE
INTERESTING TO ALSO SEE AND COMPARE THIS SOUNDING TO A 19Z
RESEARCH SOUNDING LAUNCH IN EASTERN ARKANSAS WHERE SKIES WERE
MOSTLY SUNNY.
FOR TONIGHT...SEVERE WEATHER IS STILL LIKELY AS BOTH A STRONG
SHORTWAVE OVER THE CENTRAL PLAINS AND ASSOCIATED COLD FRONT SWING
THROUGH THE MISSISSIPPI VALLEY. 12Z MODEL RUNS ARE IN VERY GOOD
AGREEMENT THAT THE BRUNT OF PRECIPITATION AND SEVERE WEATHER WILL
OCCUR BETWEEN 23-06Z...WITH A HALF TO PERHAPS ONE HALF INCHES OF
TOTAL RAINFALL. AFTER SCANNING SPC`S HHR MODEL... CONVECTION WILL
REMAIN ALONG THE COLD FRONT IN NORTHWEST ARKANSAS AND SOUTHERN
MISSOURI THROUGH THE AFTERNOON HOURS...WITH A PREFRONTAL TROUGH
DEVELOPING AND SPARKING OFF CONVECTION ALONG CROWLEY`S RIDGE BY 6PM.
WIDSPREAD STRATUS CLOUD COVER OVER WESTERN AND CENTRAL ARKANSAS MAY
BE THE REASON FOR THE GREATER FOCUS TO SHIFT TO THE PRE-FRONTAL
TROUGH. BOTH BOUNDARIES ARE EXPECTED TO COMPLETELY MERGE ALONG THE
TENNESSEE RIVER BY MIDNIGHT. STRAIGHT-LINE WINDS WITH STORMS REMAINS
THE GREATEST SEVERE THREAT AS STORM/LINE SPEEDS ARE EXPECTED TO
EXCEED 50 MPH. MOST LOCATIONS WILL SEE DEWPOINTS CLIMB INTO THE
UPPER 50S AND LOW 60S AHEAD OF THE FRONT...WITH MID AND UPPER 60S
MAKING THERE WAY INTO THE SOUTHWEST DELTA COUNTIES. STILL FEEL THAT
THIS LOCATION...THAT IS SOUTH OF I-40 AND WEST OF I-55...WILL HAVE
THE BEST CHANCE FOR A TORNADIC STORM BEFORE 02Z...AND TO A LESSER
DEGREE FURTHER NORTH AND EAST. BY 02Z STORMS WILL HAVE CROSSED INTO
WEST TENNESSEE AND INTO NORTH CENTRAL MISSISSIPPI...QUICKLY EVOLVING
INTO ONE LONG LINE OF INDIVIDUAL BOWING SEGMENTS. THIS BOUNDARY
MERGER/TRANSITION IS IN RESPONSE TO A 80KT 500MB JET CROSSING
ARKANSAS. THUS A BETTER CHANCE FOR WIND DAMAGE WILL EXIST DURING THE
MID TO LATE EVENING HOURS. MODELS INDICATE THAT CONVECTION WILL EXIT
THE MIDSOUTH BY 1AM WITH SURFACE WINDS VEERING MORE WEST
SOUTHWESTERLY. LOWS WILL FALL INTO THE UPPER 40S OVER THE NORTHWEST
COUNTIES WHERE CLEARER SKIES WILL EXIST BEFORE SUNRISE...50S WILL BE
SEEN ELSEWHERE.
THURSDAY THROUGH SATURDAY...A STRONG WEST TO NORTHWEST UPPER FLOW
WILL DOMINATE THE REGION AS A CLOSED UPPER LOW PIVOTS THROUGH THE
SOUTHERN GREAT LAKES. CLOSER TO THE SURFACE HIGH PRESSURE WILL
BUILD EASTWARD FROM THE PLAIN STATES. WEST SOUTHWESTERLY SURFACE
WINDS WILL BECOME GUSTY AGAIN TOMORROW...SO THE NEED FOR ANOTHER
WIND ADVISORY WILL NEED TO BE ACCESSED BY THE NIGHTCREW. WEAK CAA
WILL CONTINUE ON FRIDAY AND SATURDAY AS WINDS SHIFT MORE
NORTHWESTERLY. NONE-THE-LESS THE BEGINNING OF THE WEEKEND WILL BE
NICE.
SUNDAY AND MONDAY...A QUICK WARMING TREND IS ANTICIPATED AS THE
LOW LEVEL FLOW TURNS SOUTHERLY AND AN UPPER RIDGE BUILDS OVER THE
EASTERN HALF OF THE U.S. THE GFS AND EURO SHOW THE PRESENCE OF A
WEAK SHORTWAVE CLIPPING THE REGION SUNDAY NIGHT AND ON MONDAY AS
IT APPROACHES THE RIDGE AXIS. HAVE ADJUSTED A SLIGHT CHANCE FOR
RAIN UP 12 HOURS TO REFLECT THIS NEW TIMING BEGINNING SUNDAY
NIGHT. HIGHS WILL RANGE FROM FIVE TO TEN DEGREES ABOVE NORMAL.
EXTENDED PERIOD...MOSTLY DRY WEATHER AND ABOVE NORMAL
TEMPERATURES WILL PERSIST INTO THE MIDDLE OF NEXT WEEK WITH
SOUTHERLY WINDS KEEPING A FRONT STATIONARY ACROSS THE MID
MISSISSIPPI VALLEY.
JAB
AVIATION...
00Z TAF SET
NOT MUCH CHANGE FROM PREVIOUS TAF SET. SHRAS/TSRAS BEGINNING TO
DEVELOP OVER EASTERN ARKANSAS WHICH IS WHAT LATEST HRRR MODEL WAS
SHOWING. BEST TIMING FOR KMEM WILL BE BETWEEN 01-04Z...FOR KJBR
00-03Z...FOR KMKL 02-05Z...AND FOR KTUP 03-06Z. LOW CIGS AND VSBYS
WILL OCCUR WITH THE SHRAS/TSRAS. WINDS WILL SWITCH AROUND TO THE
NW BRIEFLY BEHIND THE LINE BEFORE GOING BACK TO THE WSW. SPEEDS
WILL INCREASE TO 15-20 KTS SUSTAINED BETWEEN 15-18Z. GUSTS WILL BE
BETWEEN 25-30 KTS.
KRM
AVIATION...
AVIATION...
&&
.AVIATION...
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 53 72 49 69 / 90 10 10 10
MKL 50 71 45 65 / 90 10 10 10
JBR 48 71 47 66 / 70 10 10 10
TUP 55 73 45 70 / 90 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR DUNKLIN-PEMISCOT.
MS...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR BENTON MS-COAHOMA-
DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-TALLAHATCHIE-TATE-
TUNICA-YALOBUSHA.
TN...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CARROLL-CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-HENDERSON-
HENRY-LAKE-LAUDERDALE-MADISON-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
836 PM CDT WED OCT 17 2012
.UPDATE...ADDED 2 MS COUNTIED TO TOR WATCH #667
&&
.PREV DISCUSSION... /ISSUED 826 PM CDT WED OCT 17 2012/
UPDATE...UPDATE FOR TORNADO WATCH #670.
PREV DISCUSSION... /ISSUED 601 PM CDT WED OCT 17 2012/
DISCUSSION... /ISSUED 234 PM CDT WED OCT 17 2012/
CURRENT CONDITIONS ARE FOR NOW QUITE TRANQUIL ACROSS THE MIDSOUTH
WITH DEWPOINTS SLOWLY RISING ON STRONG SOUTHERLY BREEZES.
TEMPERATURES WERE IN THE 70S WITH SUNNY TO MOSTLY SUNNY SKIES.
LATEST COLD FRONT LOCATION WAS ELONGATED FROM SOUTHWEST MISSOURI
TO JUST EAST OF DALLAS TEXAS WITH CONVECTION INITIATION JUST WEST
OF SPRINGFIELD. LATEST 18Z LZK SOUNDING SHOWING A STOUT CAP OF 5C
AT 810MB...JUST ABOVE THE STRATUS DECK. CHANCES ARE THAT IT WILL
BE LATER THIS AFTERNOON FOR CONVECTION INITIATION. WILL BE
INTERESTING TO ALSO SEE AND COMPARE THIS SOUNDING TO A 19Z
RESEARCH SOUNDING LAUNCH IN EASTERN ARKANSAS WHERE SKIES WERE
MOSTLY SUNNY.
FOR TONIGHT...SEVERE WEATHER IS STILL LIKELY AS BOTH A STRONG
SHORTWAVE OVER THE CENTRAL PLAINS AND ASSOCIATED COLD FRONT SWING
THROUGH THE MISSISSIPPI VALLEY. 12Z MODEL RUNS ARE IN VERY GOOD
AGREEMENT THAT THE BRUNT OF PRECIPITATION AND SEVERE WEATHER WILL
OCCUR BETWEEN 23-06Z...WITH A HALF TO PERHAPS ONE HALF INCHES OF
TOTAL RAINFALL. AFTER SCANNING SPC`S HHR MODEL... CONVECTION WILL
REMAIN ALONG THE COLD FRONT IN NORTHWEST ARKANSAS AND SOUTHERN
MISSOURI THROUGH THE AFTERNOON HOURS...WITH A PREFRONTAL TROUGH
DEVELOPING AND SPARKING OFF CONVECTION ALONG CROWLEY`S RIDGE BY 6PM.
WIDSPREAD STRATUS CLOUD COVER OVER WESTERN AND CENTRAL ARKANSAS MAY
BE THE REASON FOR THE GREATER FOCUS TO SHIFT TO THE PRE-FRONTAL
TROUGH. BOTH BOUNDARIES ARE EXPECTED TO COMPLETELY MERGE ALONG THE
TENNESSEE RIVER BY MIDNIGHT. STRAIGHT-LINE WINDS WITH STORMS REMAINS
THE GREATEST SEVERE THREAT AS STORM/LINE SPEEDS ARE EXPECTED TO
EXCEED 50 MPH. MOST LOCATIONS WILL SEE DEWPOINTS CLIMB INTO THE
UPPER 50S AND LOW 60S AHEAD OF THE FRONT...WITH MID AND UPPER 60S
MAKING THERE WAY INTO THE SOUTHWEST DELTA COUNTIES. STILL FEEL THAT
THIS LOCATION...THAT IS SOUTH OF I-40 AND WEST OF I-55...WILL HAVE
THE BEST CHANCE FOR A TORNADIC STORM BEFORE 02Z...AND TO A LESSER
DEGREE FURTHER NORTH AND EAST. BY 02Z STORMS WILL HAVE CROSSED INTO
WEST TENNESSEE AND INTO NORTH CENTRAL MISSISSIPPI...QUICKLY EVOLVING
INTO ONE LONG LINE OF INDIVIDUAL BOWING SEGMENTS. THIS BOUNDARY
MERGER/TRANSITION IS IN RESPONSE TO A 80KT 500MB JET CROSSING
ARKANSAS. THUS A BETTER CHANCE FOR WIND DAMAGE WILL EXIST DURING THE
MID TO LATE EVENING HOURS. MODELS INDICATE THAT CONVECTION WILL EXIT
THE MIDSOUTH BY 1AM WITH SURFACE WINDS VEERING MORE WEST
SOUTHWESTERLY. LOWS WILL FALL INTO THE UPPER 40S OVER THE NORTHWEST
COUNTIES WHERE CLEARER SKIES WILL EXIST BEFORE SUNRISE...50S WILL BE
SEEN ELSEWHERE.
THURSDAY THROUGH SATURDAY...A STRONG WEST TO NORTHWEST UPPER FLOW
WILL DOMINATE THE REGION AS A CLOSED UPPER LOW PIVOTS THROUGH THE
SOUTHERN GREAT LAKES. CLOSER TO THE SURFACE HIGH PRESSURE WILL
BUILD EASTWARD FROM THE PLAIN STATES. WEST SOUTHWESTERLY SURFACE
WINDS WILL BECOME GUSTY AGAIN TOMORROW...SO THE NEED FOR ANOTHER
WIND ADVISORY WILL NEED TO BE ACCESSED BY THE NIGHTCREW. WEAK CAA
WILL CONTINUE ON FRIDAY AND SATURDAY AS WINDS SHIFT MORE
NORTHWESTERLY. NONE-THE-LESS THE BEGINNING OF THE WEEKEND WILL BE
NICE.
SUNDAY AND MONDAY...A QUICK WARMING TREND IS ANTICIPATED AS THE
LOW LEVEL FLOW TURNS SOUTHERLY AND AN UPPER RIDGE BUILDS OVER THE
EASTERN HALF OF THE U.S. THE GFS AND EURO SHOW THE PRESENCE OF A
WEAK SHORTWAVE CLIPPING THE REGION SUNDAY NIGHT AND ON MONDAY AS
IT APPROACHES THE RIDGE AXIS. HAVE ADJUSTED A SLIGHT CHANCE FOR
RAIN UP 12 HOURS TO REFLECT THIS NEW TIMING BEGINNING SUNDAY
NIGHT. HIGHS WILL RANGE FROM FIVE TO TEN DEGREES ABOVE NORMAL.
EXTENDED PERIOD...MOSTLY DRY WEATHER AND ABOVE NORMAL
TEMPERATURES WILL PERSIST INTO THE MIDDLE OF NEXT WEEK WITH
SOUTHERLY WINDS KEEPING A FRONT STATIONARY ACROSS THE MID
MISSISSIPPI VALLEY.
JAB
AVIATION...
00Z TAF SET
NOT MUCH CHANGE FROM PREVIOUS TAF SET. SHRAS/TSRAS BEGINNING TO
DEVELOP OVER EASTERN ARKANSAS WHICH IS WHAT LATEST HRRR MODEL WAS
SHOWING. BEST TIMING FOR KMEM WILL BE BETWEEN 01-04Z...FOR KJBR
00-03Z...FOR KMKL 02-05Z...AND FOR KTUP 03-06Z. LOW CIGS AND VSBYS
WILL OCCUR WITH THE SHRAS/TSRAS. WINDS WILL SWITCH AROUND TO THE
NW BRIEFLY BEHIND THE LINE BEFORE GOING BACK TO THE WSW. SPEEDS
WILL INCREASE TO 15-20 KTS SUSTAINED BETWEEN 15-18Z. GUSTS WILL BE
BETWEEN 25-30 KTS.
KRM
AVIATION...
&&
.AVIATION...
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 53 72 49 69 / 90 10 10 10
MKL 50 71 45 65 / 90 10 10 10
JBR 48 71 47 66 / 70 10 10 10
TUP 55 73 45 70 / 90 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR DUNKLIN-PEMISCOT.
MS...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR BENTON MS-COAHOMA-
DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-TALLAHATCHIE-TATE-
TUNICA-YALOBUSHA.
TN...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CARROLL-CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-HENDERSON-
HENRY-LAKE-LAUDERDALE-MADISON-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
826 PM CDT WED OCT 17 2012
.UPDATE...UPDATE FOR TORNADO WATCH #670.
&&
.PREV DISCUSSION... /ISSUED 601 PM CDT WED OCT 17 2012/
DISCUSSION... /ISSUED 234 PM CDT WED OCT 17 2012/
CURRENT CONDITIONS ARE FOR NOW QUITE TRANQUIL ACROSS THE MIDSOUTH
WITH DEWPOINTS SLOWLY RISING ON STRONG SOUTHERLY BREEZES.
TEMPERATURES WERE IN THE 70S WITH SUNNY TO MOSTLY SUNNY SKIES.
LATEST COLD FRONT LOCATION WAS ELONGATED FROM SOUTHWEST MISSOURI
TO JUST EAST OF DALLAS TEXAS WITH CONVECTION INITIATION JUST WEST
OF SPRINGFIELD. LATEST 18Z LZK SOUNDING SHOWING A STOUT CAP OF 5C
AT 810MB...JUST ABOVE THE STRATUS DECK. CHANCES ARE THAT IT WILL
BE LATER THIS AFTERNOON FOR CONVECTION INITIATION. WILL BE
INTERESTING TO ALSO SEE AND COMPARE THIS SOUNDING TO A 19Z
RESEARCH SOUNDING LAUNCH IN EASTERN ARKANSAS WHERE SKIES WERE
MOSTLY SUNNY.
FOR TONIGHT...SEVERE WEATHER IS STILL LIKELY AS BOTH A STRONG
SHORTWAVE OVER THE CENTRAL PLAINS AND ASSOCIATED COLD FRONT SWING
THROUGH THE MISSISSIPPI VALLEY. 12Z MODEL RUNS ARE IN VERY GOOD
AGREEMENT THAT THE BRUNT OF PRECIPITATION AND SEVERE WEATHER WILL
OCCUR BETWEEN 23-06Z...WITH A HALF TO PERHAPS ONE HALF INCHES OF
TOTAL RAINFALL. AFTER SCANNING SPC`S HHR MODEL... CONVECTION WILL
REMAIN ALONG THE COLD FRONT IN NORTHWEST ARKANSAS AND SOUTHERN
MISSOURI THROUGH THE AFTERNOON HOURS...WITH A PREFRONTAL TROUGH
DEVELOPING AND SPARKING OFF CONVECTION ALONG CROWLEY`S RIDGE BY 6PM.
WIDSPREAD STRATUS CLOUD COVER OVER WESTERN AND CENTRAL ARKANSAS MAY
BE THE REASON FOR THE GREATER FOCUS TO SHIFT TO THE PRE-FRONTAL
TROUGH. BOTH BOUNDARIES ARE EXPECTED TO COMPLETELY MERGE ALONG THE
TENNESSEE RIVER BY MIDNIGHT. STRAIGHT-LINE WINDS WITH STORMS REMAINS
THE GREATEST SEVERE THREAT AS STORM/LINE SPEEDS ARE EXPECTED TO
EXCEED 50 MPH. MOST LOCATIONS WILL SEE DEWPOINTS CLIMB INTO THE
UPPER 50S AND LOW 60S AHEAD OF THE FRONT...WITH MID AND UPPER 60S
MAKING THERE WAY INTO THE SOUTHWEST DELTA COUNTIES. STILL FEEL THAT
THIS LOCATION...THAT IS SOUTH OF I-40 AND WEST OF I-55...WILL HAVE
THE BEST CHANCE FOR A TORNADIC STORM BEFORE 02Z...AND TO A LESSER
DEGREE FURTHER NORTH AND EAST. BY 02Z STORMS WILL HAVE CROSSED INTO
WEST TENNESSEE AND INTO NORTH CENTRAL MISSISSIPPI...QUICKLY EVOLVING
INTO ONE LONG LINE OF INDIVIDUAL BOWING SEGMENTS. THIS BOUNDARY
MERGER/TRANSITION IS IN RESPONSE TO A 80KT 500MB JET CROSSING
ARKANSAS. THUS A BETTER CHANCE FOR WIND DAMAGE WILL EXIST DURING THE
MID TO LATE EVENING HOURS. MODELS INDICATE THAT CONVECTION WILL EXIT
THE MIDSOUTH BY 1AM WITH SURFACE WINDS VEERING MORE WEST
SOUTHWESTERLY. LOWS WILL FALL INTO THE UPPER 40S OVER THE NORTHWEST
COUNTIES WHERE CLEARER SKIES WILL EXIST BEFORE SUNRISE...50S WILL BE
SEEN ELSEWHERE.
THURSDAY THROUGH SATURDAY...A STRONG WEST TO NORTHWEST UPPER FLOW
WILL DOMINATE THE REGION AS A CLOSED UPPER LOW PIVOTS THROUGH THE
SOUTHERN GREAT LAKES. CLOSER TO THE SURFACE HIGH PRESSURE WILL
BUILD EASTWARD FROM THE PLAIN STATES. WEST SOUTHWESTERLY SURFACE
WINDS WILL BECOME GUSTY AGAIN TOMORROW...SO THE NEED FOR ANOTHER
WIND ADVISORY WILL NEED TO BE ACCESSED BY THE NIGHTCREW. WEAK CAA
WILL CONTINUE ON FRIDAY AND SATURDAY AS WINDS SHIFT MORE
NORTHWESTERLY. NONE-THE-LESS THE BEGINNING OF THE WEEKEND WILL BE
NICE.
SUNDAY AND MONDAY...A QUICK WARMING TREND IS ANTICIPATED AS THE
LOW LEVEL FLOW TURNS SOUTHERLY AND AN UPPER RIDGE BUILDS OVER THE
EASTERN HALF OF THE U.S. THE GFS AND EURO SHOW THE PRESENCE OF A
WEAK SHORTWAVE CLIPPING THE REGION SUNDAY NIGHT AND ON MONDAY AS
IT APPROACHES THE RIDGE AXIS. HAVE ADJUSTED A SLIGHT CHANCE FOR
RAIN UP 12 HOURS TO REFLECT THIS NEW TIMING BEGINNING SUNDAY
NIGHT. HIGHS WILL RANGE FROM FIVE TO TEN DEGREES ABOVE NORMAL.
EXTENDED PERIOD...MOSTLY DRY WEATHER AND ABOVE NORMAL
TEMPERATURES WILL PERSIST INTO THE MIDDLE OF NEXT WEEK WITH
SOUTHERLY WINDS KEEPING A FRONT STATIONARY ACROSS THE MID
MISSISSIPPI VALLEY.
JAB
AVIATION...
00Z TAF SET
NOT MUCH CHANGE FROM PREVIOUS TAF SET. SHRAS/TSRAS BEGINNING TO
DEVELOP OVER EASTERN ARKANSAS WHICH IS WHAT LATEST HRRR MODEL WAS
SHOWING. BEST TIMING FOR KMEM WILL BE BETWEEN 01-04Z...FOR KJBR
00-03Z...FOR KMKL 02-05Z...AND FOR KTUP 03-06Z. LOW CIGS AND VSBYS
WILL OCCUR WITH THE SHRAS/TSRAS. WINDS WILL SWITCH AROUND TO THE
NW BRIEFLY BEHIND THE LINE BEFORE GOING BACK TO THE WSW. SPEEDS
WILL INCREASE TO 15-20 KTS SUSTAINED BETWEEN 15-18Z. GUSTS WILL BE
BETWEEN 25-30 KTS.
KRM
&&
.AVIATION...
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 53 72 49 69 / 90 10 10 10
MKL 50 71 45 65 / 90 10 10 10
JBR 48 71 47 66 / 70 10 10 10
TUP 55 73 45 70 / 90 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR DUNKLIN-PEMISCOT.
MS...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR BENTON MS-COAHOMA-
DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-TALLAHATCHIE-TATE-
TUNICA-YALOBUSHA.
TN...WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CARROLL-CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-HENDERSON-
HENRY-LAKE-LAUDERDALE-MADISON-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
ISSUED BY NATIONAL WEATHER SERVICE PENDLETON OR
1035 AM PDT TUE OCT 16 2012
.SYNOPSIS...WINDY CONDITIONS WITH SCATTERED RAIN AND HIGH MOUNTAIN
SNOW SHOWERS WILL AFFECT THE REGION TODAY. WIND GUSTS OF 35 TO 50 MPH
WILL BE LIKELY THROUGH THIS EVENING OVER PORTIONS OF THE INLAND
NORTHWEST. A DRIER, MORE STABLE PATTERN IS EXPECTED FOR WEDNESDAY
AND THURSDAY, BEFORE MORE PRECIPITATION CHANCES ENTER LATE IN THE
WEEK WITH COOLER TEMPERATURES.
&&
.UPDATE...ONLY MINOR UPDATES WERE MADE TO THE CURRENT FORECAST.
ISOLATED THUNDERSTORMS HAVE BEEN OBSERVED OVER THE IDAHO
PANHANDLE, SO I EXTENDED THE THE THREAT OF THUNDERSTORMS UNTIL
LATE MORNING. A FEW UPDATES WERE MADE TO INCREASE TEMPERATURES IN
THE PALOUSE AND LEWISTON AREAS. WINDS ARE MEETING ADVISORY
CRITERIA (I.E. 25-35 MPH GUSTING TO 45-50 MPH) ACROSS THE COLUMBIA
BASIN AND THE WASHINGTON PALOUSE, AND I INCLUDED THE CAMAS PRAIRIE
AREA IN THE ADVISORY.
&&
.AVIATION...
18Z TAFS: MAIN IMPACTS TODAY WILL BE WINDS. GUSTY WESTERLY WINDS
WILL CONTINUE THROUGH THE AFTERNOON BEFORE DIMINISHING THIS EVENING.
SUSTAINED WINDS WILL BE 15-30KT WITH GUSTS 30-40KT. DOWNSLOPE FLOW
OFF THE CASCADES WILL PROVIDE MAINLY CLEAR SKIES FOR THE COLUMBIA
BASIN TAF SITES WITH SCT-BKN 040-060 ELSEWHERE. WINDS WILL DECREASE
TO 5-15KT LATER THIS EVENING INTO THE OVERNIGHT PERIOD. 94
&&
.PREV DISCUSSION... /ISSUED 436 AM PDT TUE OCT 16 2012/
..VERY WINDY CONDITIONS TODAY...
TODAY AND TONIGHT...THE COLD FRONT CONTINUES TO MOVE SOUTHEAST
ACROSS THE FORECAST AREA THIS MORNING WITH THE BACK EDGE JUST SOUTH
OF THE I-90 CORRIDOR AS OF 08Z. THE MAIN AREA OF STEADY RAIN IS
CONFINED TO SHOSHONE COUNTY BUT WIDELY SCATTERED SHOWERS ARE
POPPING UP ALL ACROSS THE AREA IN THE UNSTABLE POST FRONTAL AIR
MASS. A FEW LIGHTNING STRIKES HAVE BEEN RECORDED ACROSS THE EXTREME
NORTHERN CASCADES AND ACROSS SOUTHERN BC. THE COLD POOL ALOFT WILL
KEEP THINGS UNSETTLED ENOUGH FOR A SLIGHT CHANCE OF THUNDERSTORMS
THROUGH ABOUT 15Z BEFORE THE BEST FORCING MOVES EAST. GUSTY WINDS
ARE STARTING TO INCREASE AS THE SURFACE PRESSURE GRADIENT
STRENGTHENS BETWEEN THE DEEPENING LOW OVER SOUTHERN ALBERTA AND HIGH
PRESSURE OFF THE COAST. THE GRADIENT IS EXPECTED TO MAX OUT LATE
THIS MORNING TO EARLY AFTERNOON. THE BENCHMARK THAT WILL SUPPORT A
HIGH WIND WARNING IS AT LEAST A 24MB DIFFERENCE BETWEEN LETHBRIDGE,
ALBERTA (CYQL) AND YAKIMA (KYKM) ALONG WITH SYNOPTIC SUPPORT FROM A
JET STREAK OVERHEAD. WE WILL BE JUST SHY OF THE GRADIENT AND THE JET
WILL SAG TO THE SOUTH THIS AFTERNOON. THIS LIKELY MEANS THAT WE WILL
BE SEEING A HIGH END WIND ADVISORY. THERE COULD POSSIBLY BE ONE OR
TWO OF THE WINDIER SITES BREAKING INTO HIGH WIND CRITERIA BUT
WIDESPREAD DAMAGING WINDS ARE NOT EXPECTED WITH THIS SYSTEM. IT WILL
ALSO BE A FAST MOVER, WITH THE LOW SLIDING INTO THE CANADIAN
PRAIRIES BY 00Z, WEAKENING THE GRADIENT. NO CHANGES MADE TO THE
ONGOING WIND ADVISORY AT THIS TIME.
ANOTHER CONCERN WILL BE SNOW LEVELS FOR THE EAST SLOPES OF THE
CASCADES. MODELS ARE BRINGING THE 850MB 0C LINE ALONG THE CREST WITH
THE NAM12 DOWN TO -1C THIS MORNING. RADAR MOSAIC IS SHOWING SOME
EVIDENCE OF A CONVERGENT ZONE. THE HRRR MODEL AGREES, BUT SHOWS THE
PLUME DRIFTING SOUTH ALONG THE CREST INTO SLIGHTLY WARMER AIR.
DEPENDING ON THE LOCATION AND PERSISTENCE OF THIS FEATURE, SOME OF
THE HIGHER VALLEYS COULD SEE SOME LIGHT SNOWFALL ACCUMULATION. AFTER
A RELATIVELY MILD MORNING, DUE TO STRONG MIXING BY GUSTY WINDS,
TEMPERATURES WILL NOT WARM VERY MUCH TODAY AS COLD AIR ADVECTION
TAKES OVER. EXPECT CHILLY TEMPERATURES TONIGHT WITH MOST OF THE
NORTHERN VALLEYS DIPPING BELOW THE FREEZING MARK. FOR OTHER VALLEY
LOCATIONS, MID 30S WILL BE COMMON. /KELCH
WEDNESDAY THROUGH THURSDAY...LATEST MODELS ARE IN GOOD AGREEMENT
FOR THIS PERIOD. A QUITE BREAK WILL GRACE THE REGION AS A WEAK
BUT PERCEPTIBLE SHORT WAVE RIDGE BUILDS OVER THE FORECAST AREA IN
THE WAKE OF TUESDAY`S UNPLEASANTNESS. RESIDUAL BREEZY WINDS AND
LINGERING SHOWERS OVER THE IDAHO PANHANDLE WILL DECREASE WEDNESDAY
MORNING AS SURFACE HIGH PRESSURE SETTLES OVER THE REGION. WEDNESDAY`S
HIGHS WILL PEAK RIGHT AROUND SEASONAL NORMAL WITH GENERALLY PARTLY
CLOUDY TO MOSTLY SUNNY SKIES. THE QUIET BREAK WILL CONTINUE ON
THURSDAY ALTHOUGH THE RIDGE AXIS WILL PASS TO THE EAST OF THE
REGION AND OPEN THE WAY FOR INCREASING HIGH CLOUDS AS THE NEXT
WEATHER SYSTEM APPROACHES. THE RETREAT OF THE RIDGE AXIS WILL
ALLOW SOME WARM ADVECTION TO BEGIN ON THURSDAY IN THE PRE-FRONTAL
SOUTHWEST FLOW REGIME...PROMOTING HIGH TEMPERATURES ONCE AGAIN
SLIGHTLY ABOVE NORMAL...BUT WITH SUNSHINE FILTERED THROUGH
THICKENING CLOUDS ESPECIALLY ACROSS THE NORTHERN ZONES.
THURSDAY NIGHT AND FRIDAY...THE GFS AND ECMWF MODELS ADVERTISE A
RIDGE BREAKDOWN AND SUBSEQUENT COLD FRONT PASSAGE EITHER THURSDAY
NIGHT (GFS) OR FRIDAY (EC). BOTH MODELS HAVE STUCK TO THEIR
RESPECTIVE TIMING DIFFERENCES OVER THE LAST FEW RUNS. THE DRIVING
FORCE OF A 120-140KT JET OVER THE GULF OF ALASKA ASSOCIATED WITH
THIS WAVE SUGGEST THE FASTER GFS MAY BE THE BEST SOLUTION TO WORK
WITH. FORECAST WILL BE BASED UPON THIS REASONING...WHICH YIELDS
HIGH POPS OVER MUCH OF THE FORECAST AREA THURSDAY NIGHT AND INTO
FRIDAY MORNING AS A STRONG FETCH OF PRECIPITABLE WATER ENHANCES
ALONG THE COLD FRONT WITH GOOD AND WELL DEFINED JET DIVERGENCE AND
DIFFERENTIAL PVA. HIGH TEMPERATURES FRIDAY ARE LOW
CONFIDENCE...WITH THE CURRENT FORECAST REFLECTING AN ASSUMPTION
OF A MORNING PRECIPITATION THREAT FOLLOWED BY GOOD AFTERNOON
ADIABATIC MIXING PROMOTING HIGH TEMPERATURES ABOVE AVERAGE...BUT
IF THE EC IS CORRECT THEN HIGHS MAY TOP OUT CLOSER TO AVERAGE. IN
ANY EVENT...AFTER THE RELATIVELY BENIGN CONDITIONS OF WEDNESDAY
AND THURSDAY...THERE IS HIGH CONFIDENCE THAT FRIDAY WILL BRING A
CHANGE TO THIS PATTERN.
FRIDAY NIGHT THROUGH MONDAY...THINGS GET RATHER MESSY AND
UNCERTAIN DURING THIS PERIOD WITH RESPECT TO TIMING MULTIPLE MINOR
WAVES AND FRONTS IN A MUCH MORE PROGRESSIVE...COOLER AND WET
PATTERN. WHERE CERTAINTY IS HIGHER IS THE OVERALL PATTERN
REFLECTED BY ALL THE LATEST MODELS FEATURING A COOL ZONAL OR
MODERATELY COLD TROFFY FLOW REGIME WITH THE STORM TRACK TO THE
SOUTH OF THE FORECAST AREA. THIS ARGUES FOR A BROAD BRUSH APPROACH
FEATURING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW EACH DAY
THROUGH THE WEEKEND AND EARLY NEXT WEEK...WITH THE ADDED
POSSIBILITY OF SOME OVERNIGHT NON-ACCUMULATING SNOW FLAKES DOWN
TO THE VALLEY AND BASIN FLOORS IF ANY PARTICULAR DISTURBANCE RIDES
THROUGH DURING THE OVERNIGHT OR EARLY MORNING HOURS. THE DEEP
BASIN IN THE LEE OF THE CASCADES WILL PROBABLY MISS OUT ON ANY
SIGNIFICANT PRECIPITATION GIVEN THE RAIN SHADOW PROMOTING MEAN
WESTERLY FLOW. DURING THIS PERIOD THE MOUNTAINS ABOVE 4000 TO 5000 FEET
ARE LIKELY TO RECEIVE THEIR FIRST SIGNIFICANT SNOW
ACCUMULATIONS...SLOWLY BUILDING UP TO THREE TO SEVEN INCHES
THROUGH THE WEEKEND. THUS...CONFIDENCE IS HIGH FOR A RAW...BREEZY
AND OCCASIONALLY WET REGIME DURING THIS PERIOD...ALTHOUGH
CONFIDENCE IS LOW REGARDING TIMING OF ANY OF THE EXPECTED
TRANSIENT FOCUSING MECHANISMS AND FRONTS. /FUGAZZI
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 58 37 54 37 60 43 / 10 10 0 0 10 60
COEUR D`ALENE 60 34 53 33 60 40 / 20 10 0 0 10 60
PULLMAN 57 31 53 36 62 42 / 30 10 0 0 10 60
LEWISTON 63 39 58 40 68 47 / 20 10 0 0 10 50
COLVILLE 60 29 57 34 60 36 / 20 10 10 0 10 60
SANDPOINT 53 33 52 32 57 39 / 40 10 10 0 10 60
KELLOGG 50 35 48 32 56 39 / 80 20 10 0 10 70
MOSES LAKE 62 34 60 37 64 42 / 10 0 0 0 10 20
WENATCHEE 58 40 57 39 65 45 / 10 0 0 0 10 30
OMAK 61 33 59 37 62 38 / 0 0 0 10 10 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY UNTIL 8 PM PDT THIS EVENING FOR COEUR D`ALENE AREA-
IDAHO PALOUSE-LEWIS AND SOUTHERN NEZ PERCE COUNTIES-
LEWISTON AREA.
WA...WIND ADVISORY UNTIL 8 PM PDT THIS EVENING FOR LOWER GARFIELD AND
ASOTIN COUNTIES-MOSES LAKE AREA-SPOKANE AREA-UPPER COLUMBIA
BASIN-WASHINGTON PALOUSE-WATERVILLE PLATEAU-WENATCHEE AREA.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
436 AM PDT Tue Oct 16 2012
.SYNOPSIS...Windy conditions with scattered rain and high mountain
snow showers will affect the region today. Wind gusts of 35 to 50 mph
will be likely through this evening over portions of the Inland
Northwest. A drier, more stable pattern is expected for Wednesday
and Thursday, before more precipitation chances enter late in the
week with cooler temperatures.
&&
.DISCUSSION...
...VERY WINDY CONDITIONS TODAY...
Today and tonight...The cold front continues to move southeast
across the forecast area this morning with the back edge just south
of the I-90 corridor as of 08Z. The main area of steady rain is
confined to Shoshone county but widely scattered showers are
popping up all across the area in the unstable post frontal air
mass. A few lightning strikes have been recorded across the extreme
northern Cascades and across southern BC. The cold pool aloft will
keep things unsettled enough for a slight chance of thunderstorms
through about 15Z before the best forcing moves east. Gusty winds
are starting to increase as the surface pressure gradient
strengthens between the deepening low over southern Alberta and high
pressure off the coast. The gradient is expected to max out late
this morning to early afternoon. The benchmark that will support a
high wind warning is at least a 24mb difference between Lethbridge,
Alberta (CYQL) and Yakima (KYKM) along with synoptic support from a
jet streak overhead. We will be just shy of the gradient and the jet
will sag to the south this afternoon. This likely means that we will
be seeing a high end wind advisory. There could possibly be one or
two of the windier sites breaking into high wind criteria but
widespread damaging winds are not expected with this system. It will
also be a fast mover, with the low sliding into the Canadian
Prairies by 00z, weakening the gradient. No changes made to the
ongoing wind advisory at this time.
Another concern will be snow levels for the east slopes of the
Cascades. Models are bringing the 850mb 0C line along the crest with
the NAM12 down to -1C this morning. Radar mosaic is showing some
evidence of a convergent zone. The HRRR model agrees, but shows the
plume drifting south along the crest into slightly warmer air.
Depending on the location and persistence of this feature, some of
the higher valleys could see some light snowfall accumulation. After
a relatively mild morning, due to strong mixing by gusty winds,
temperatures will not warm very much today as cold air advection
takes over. Expect chilly temperatures tonight with most of the
northern valleys dipping below the freezing mark. For other valley
locations, mid 30s will be common. /Kelch
Wednesday through Thursday...Latest models are in good agreement
for this period. A quite break will grace the region as a weak
but perceptible short wave ridge builds over the forecast area in
the wake of Tuesday`s unpleasantness. Residual breezy winds and
lingering showers over the Idaho Panhandle will decrease Wednesday
morning as surface high pressure settles over the region. Wednesday`s
highs will peak right around seasonal normal with generally partly
cloudy to mostly sunny skies. The quiet break will continue on
Thursday although the ridge axis will pass to the east of the
region and open the way for increasing high clouds as the next
weather system approaches. The retreat of the ridge axis will
allow some warm advection to begin on Thursday in the pre-frontal
southwest flow regime...promoting high temperatures once again
slightly above normal...but with sunshine filtered through
thickening clouds especially across the northern zones.
Thursday night and Friday...The GFS and ECMWF models advertise a
ridge breakdown and subsequent cold front passage either Thursday
night (GFS) or Friday (EC). Both models have stuck to their
respective timing differences over the last few runs. The driving
force of a 120-140kt jet over the Gulf Of Alaska associated with
this wave suggest the faster GFS may be the best solution to work
with. Forecast will be based upon this reasoning...which yields
high pops over much of the forecast area Thursday night and into
Friday morning as a strong fetch of precipitable water enhances
along the cold front with good and well defined jet divergence and
differential PVA. High temperatures Friday are low
confidence...with the current forecast reflecting an assumption
of a morning precipitation threat followed by good afternoon
adiabatic mixing promoting high temperatures above average...but
if the EC is correct then highs may top out closer to average. In
any event...after the relatively benign conditions of Wednesday
and Thursday...there is high confidence that Friday will bring a
change to this pattern.
Friday night through Monday...Things get rather messy and
uncertain during this period with respect to timing multiple minor
waves and fronts in a much more progressive...cooler and wet
pattern. Where certainty is higher is the overall pattern
reflected by all the latest models featuring a cool zonal or
moderately cold troffy flow regime with the storm track to the
south of the forecast area. This argues for a broad brush approach
featuring a chance of valley rain and mountain snow each day
through the weekend and early next week...with the added
possibility of some overnight non-accumulating snow flakes down
to the valley and basin floors if any particular disturbance rides
through during the overnight or early morning hours. The deep
basin in the lee of the Cascades will probably miss out on any
significant precipitation given the rain shadow promoting mean
westerly flow. During this period the mountains above 4000 to 5000 feet
are likely to receive their first significant snow
accumulations...slowly building up to three to seven inches
through the weekend. Thus...confidence is high for a raw...breezy
and occasionally wet regime during this period...although
confidence is low regarding timing of any of the expected
transient focusing mechanisms and fronts. /Fugazzi
&&
.AVIATION...
12Z TAFS: The upper level trough has moved over the region this
morning with scattered thunderstorms across the panhandle of
Idaho. Convection has moved east of most terminals, except KLWS.
A line of storms will affect extreme southeast WA and the central
panhandle through about 15z. Moist upslope flow into KGEG, KSFF, KCOE
and at KPUW will result in some low stratus before drier air aloft
begins to clear skies out and improve conditions. Winds are beginning
to gust out of the west and southwest and will intensify by 18Z
with gusts to of 35 to 40 kts common. Scattered showers will
affect the Idaho panhandle through this afternoon, then diminish.
Winds will start to slacken by 01Z then become light after 06Z. As
winds become light, low stratus may form at any and all terminals.
/EK
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 56 37 54 37 60 43 / 30 10 0 0 10 60
Coeur d`Alene 55 34 53 33 60 40 / 50 10 0 0 10 60
Pullman 57 31 53 36 62 42 / 70 10 0 0 10 60
Lewiston 63 39 58 40 68 47 / 70 10 0 0 10 50
Colville 60 29 57 34 60 36 / 30 10 10 0 10 60
Sandpoint 53 33 52 32 57 39 / 70 10 10 0 10 60
Kellogg 50 35 48 32 56 39 / 90 20 10 0 10 70
Moses Lake 62 34 60 37 64 42 / 10 0 0 0 10 20
Wenatchee 58 40 57 39 65 45 / 10 0 0 0 10 30
Omak 61 33 59 37 62 38 / 10 0 0 10 10 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until 8 PM PDT this evening for Coeur d`Alene Area-
Idaho Palouse-Lewiston Area.
WA...Wind Advisory until 8 PM PDT this evening for Lower Garfield and
Asotin Counties-Moses Lake Area-Spokane Area-Upper Columbia
Basin-Washington Palouse-Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
221 AM PDT Tue Oct 16 2012
.SYNOPSIS...Windy conditions with scattered rain and high mountain
snow showers will affect the region today. Wind gusts of 35 to 50 mph
will be likely through this evening over portions of the Inland
Northwest. A drier, more stable pattern is expected for Wednesday
and Thursday, before more precipitation chances enter late in the
week with cooler temperatures.
&&
.DISCUSSION...
...VERY WINDY CONDITIONS TODAY...
Today and tonight...The cold front continues to move southeast
across the forecast area this morning with the back edge just south
of the I-90 corridor as of 08Z. The main area of steady rain is
confined to Shoshone county but widely scattered showers are
popping up all across the area in the unstable post frontal air
mass. A few lightning strikes have been recorded across the extreme
northern Cascades and across southern BC. The cold pool aloft will
keep things unsettled enough for a slight chance of thunderstorms
through about 15Z before the best forcing moves east. Gusty winds
are starting to increase as the surface pressure gradient
strengthens between the deepening low over southern Alberta and high
pressure off the coast. The gradient is expected to max out late
this morning to early afternoon. The benchmark that will support a
high wind warning is at least a 24mb difference between Lethbridge,
Alberta (CYQL) and Yakima (KYKM) along with synoptic support from a
jet streak overhead. We will be just shy of the gradient and the jet
will sag to the south this afternoon. This likely means that we will
be seeing a high end wind advisory. There could possibly be one or
two of the windier sites breaking into high wind criteria but
widespread damaging winds are not expected with this system. It will
also be a fast mover, with the low sliding into the Canadian
Prairies by 00z, weakening the gradient. No changes made to the
ongoing wind advisory at this time.
Another concern will be snow levels for the east slopes of the
Cascades. Models are bringing the 850mb 0C line along the crest with
the NAM12 down to -1C this morning. Radar mosaic is showing some
evidence of a convergent zone. The HRRR model agrees, but shows the
plume drifting south along the crest into slightly warmer air.
Depending on the location and persistence of this feature, some of
the higher valleys could see some light snowfall accumulation. After
a relatively mild morning, due to strong mixing by gusty winds,
temperatures will not warm very much today as cold air advection
takes over. Expect chilly temperatures tonight with most of the
northern valleys dipping below the freezing mark. For other valley
locations, mid 30s will be common. /Kelch
Wednesday through Thursday...Latest models are in good agreement
for this period. A quite break will grace the region as a weak
but perceptible short wave ridge builds over the forecast area in
the wake of Tuesday`s unpleasantness. Residual breezy winds and
lingering showers over the Idaho Panhandle will decrease Wednesday
morning as surface high pressure settles over the region. Wednesday`s
highs will peak right around seasonal normal with generally partly
cloudy to mostly sunny skies. The quiet break will continue on
Thursday although the ridge axis will pass to the east of the
region and open the way for increasing high clouds as the next
weather system approaches. The retreat of the ridge axis will
allow some warm advection to begin on Thursday in the pre-frontal
southwest flow regime...promoting high temperatures once again
slightly above normal...but with sunshine filtered through
thickening clouds especially across the northern zones.
Thursday night and Friday...The GFS and ECMWF models advertise a
ridge breakdown and subsequent cold front passage either Thursday
night (GFS) or Friday (EC). Both models have stuck to their
respective timing differences over the last few runs. The driving
force of a 120-140kt jet over the Gulf Of Alaska associated with
this wave suggest the faster GFS may be the best solution to work
with. Forecast will be based upon this reasoning...which yields
high pops over much of the forecast area Thursday night and into
Friday morning as a strong fetch of precipitable water enhances
along the cold front with good and well defined jet divergence and
differential PVA. High temperatures Friday are low
confidence...with the current forecast reflecting an assumption
of a morning precipitation threat followed by good afternoon
adiabatic mixing promoting high temperatures above average...but
if the EC is correct then highs may top out closer to average. In
any event...after the relatively benign conditions of Wednesday
and Thursday...there is high confidence that Friday will bring a
change to this pattern.
Friday night through Monday...Things get rather messy and
uncertain during this period with respect to timing multiple minor
waves and fronts in a much more progressive...cooler and wet
pattern. Where certainty is higher is the overall pattern
reflected by all the latest models featuring a cool zonal or
moderately cold troffy flow regime with the storm track to the
south of the forecast area. This argues for a broad brush approach
featuring a chance of valley rain and mountain snow each day
through the weekend and early next week...with the added
possibility of some overnight non-accumulating snow flakes down
to the valley and basin floors if any particular disturbance rides
through during the overnight or early morning hours. The deep
basin in the lee of the Cascades will probably miss out on any
significant precipitation given the rain shadow promoting mean
westerly flow. During this period the mountains above 4000 to 5000 feet
are likely to receive their first significant snow
accumulations...slowly building up to three to seven inches
through the weekend. Thus...confidence is high for a raw...breezy
and occasionally wet regime during this period...although
confidence is low regarding timing of any of the expected
transient focusing mechanisms and fronts. /Fugazzi
&&
.AVIATION...
06Z TAFS: The mid level cold front pushed east of all the
terminals this evening with stratiform rainfall transitioning to
convective showers. The atmosphere will begin to destabilize
through the night as the upper level trough pushes over the
region. This may result in some showers developing into
thunderstorms, but confidence is too low to include at any of the
taf sites. Moist upslope flow into KGEG, KSFF, KCOE and at KPUW
will result in some low stratus before drier air aloft begins to
clear skies out and improve conditions. The surface cold front
will move east of the Cascades over the next few hours with winds
beginning to gust out of the west and southwest by the early
morning hours and intensifying by the afternoon on Tuesday. Until
the surface front pushes through, expect some low level wind shear
at all terminals tonight. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 56 37 54 37 60 43 / 30 10 0 0 10 60
Coeur d`Alene 55 34 53 33 60 40 / 50 10 0 0 10 60
Pullman 57 31 53 36 62 42 / 70 10 0 0 10 60
Lewiston 63 39 58 40 68 47 / 70 10 0 0 10 50
Colville 60 29 57 34 60 36 / 30 10 10 0 10 60
Sandpoint 53 33 52 32 57 39 / 70 10 10 0 10 60
Kellogg 50 35 48 32 56 39 / 90 20 10 0 10 70
Moses Lake 62 34 60 37 64 42 / 10 0 0 0 10 20
Wenatchee 58 40 57 39 65 45 / 10 0 0 0 10 30
Omak 61 33 59 37 62 38 / 10 0 0 10 10 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until 8 PM PDT this evening for Coeur d`Alene Area-
Idaho Palouse-Lewiston Area.
WA...Wind Advisory until 8 PM PDT this evening for Lower Garfield and
Asotin Counties-Moses Lake Area-Spokane Area-Upper Columbia
Basin-Washington Palouse-Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
107 AM CDT THU OCT 18 2012
.AVIATION...18/06Z TAF CYCLE
CDFNT AND ASSOCD CONVECTION HAS PUSHED SE OF THE FA ATTM. VFR
CONDS WL PREVAIL THRU THE PD. GUSTY W/NW WINDS WL INCRS BY MID TO
LATE MRNG ACRS THE AREA...WITH GUSTS UP TO 25 KTS COMMON. WINDS WL
DIMINISH DURG THE EARLY EVENING HRS. /44/
&&
.PREV DISCUSSION... /ISSUED 207 PM CDT WED OCT 17 2012/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
FIRST PERIOD WILL STAY WITH THE HIGH POPS WITH SEVERE STORM
MENTION AS THE CONVECTION OVER EASTERN OK WITH WORK ITS WAY EAST
WITH THE BOUNDARY. HAVE SEEN A PREFRONTAL TROUGH DEVELOP SOME
CONVECTION AND THEN ADDITIONAL LINE ALONG AND WITH THE COLD FRONT.
WRF AND RR MODELS DEPICT THIS SCENARIO. THE CONVECTION SHOULD MOVE
ACROSS THE STATE FAIRLY QUICKLY WITH THE GOOD MID LEVEL WINDS AND
REACH EASTERN AR AROUND 06Z TO 10Z. QPF WITH THIS SYSTEM IS A BIT
UNCERTAIN DUE TO SPEED AND HOW MUCH MOISTURE WILL BE ADVECTED INTO
THE CONVECTION. WENT WITH HIGHEST FROM A 1/4 TO 3/4 INCH WITH A
FEW ISOLATED HIGHER SPOTS. SOME LOCATIONS WILL SEE ONLY SEE A FEW
TENTHS.
ON THURSDAY...THE SURFACE HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT AND BRING QUITE A DRY AND COOL AIR MASS. WINDS WILL BE
ELEVATED ESPECIALLY OVER NORTHERN AR TO CENTRAL...AND WITH MINIMUM RH
VALUES DROPPING INTO THE 20S...A FIRE WEATHER DANGER STATEMENT
WILL BE NEED. SOIL MOISTURE LEVELS ARE ABOVE CRITICAL VALUES AT
THIS TIME. DUE TO THE STRONG SURFACE AND UPPER SYSTEM...THE COOLER
AIR MASS WILL HOLD OVER THE AREA THROUGH SATURDAY. ANY CLOUDS ON
THURSDAY OVER NORTHERN AR WILL THIN INTO FRIDAY AND MOSTLY SUNNY
SKIES WILL BE SEEN FRIDAY AND SATURDAY. TEMPS WILL BE AT OR BELOW
THROUGH THE PERIOD THEN A WARMING TREND INTO NEXT WEEK.
LONG TERM...SUNDAY THROUGH WEDNESDAY...
A SOMEWHAT FLAT RIDGE WILL DEVELOP IN THE UPPER LEVEL FLOW ACROSS
THE REGION DURING THE EXTENDED TERM. A FEW SHORTWAVES WILL LIKELY
RIDE OVER THE RIDGE IN THE SWLY FLOW ALOFT. EXTENDED TERM MODELS ARE
IN DISAGREEMENT OVER THE HANDLING OF A SHORTWAVE DURING THIS TIME
FRAME...WITH THE GFS BEING MUCH WETTER AND GENERATING A WIDE AREA OF
PRECIP ACROSS THE NWRN PART OF THE STATE...WITH A DRIER ECMWF AND A
CANADIAN MODEL THAT IS SOMEWHAT IN BETWEEN.
AT THIS TIME I AM LEANING MORE TOWARD THE ECMWF SOLUTION BUT I AM
PUTTING SOME LOW POPS ACROSS THE NORTHERN/NWRN ZONES ON TUESDAY AND
TUESDAY NIGHT PER THE CANADIAN MODEL.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TUCSON AZ
215 AM MST THU OCT 18 2012
.SYNOPSIS...A MODEST MOISTURE INCREASE WILL BRING SOME CLOUDS AND A
FEW LIGHT SHOWERS TODAY...MAINLY SOUTH AND WEST OF TUCSON. OTHERWISE
HIGH PRESSURE WILL CONTINUE TO BRING WARM TEMPERATURES TO THE AREA
INTO THE COMING WEEKEND. AS HIGH PRESSURE WEAKENS OVER THE REGION
EARLY NEXT WEEK...TEMPERATURES WILL FALL BACK TO NEAR SEASONAL
AVERAGES.
&&
.DISCUSSION...THE MOISTURE TREND CONTINUES THIS MORNING...WITH
SURFACE DEWPTS UP 10 TO 20 DEGREES OVER THE PAST 24 HOURS...PUTTING
MOST LOCATIONS FROM TUCSON SOUTHWARD INTO THE 40S AND 50S. BLENDED
TOTAL PW ESTIMATES NOW IN THE 3/4 INCH RANGE WITH DEEPER VALUES JUST
SOUTH OF THE INTERNATIONAL BORDER. THE CORE OF THE MOISTURE
REMAINING WITH WHAT USED TO BE PAUL (NO LONGER EVEN A DEPRESSION) IS
JUST WEST OF THE NORTHERN BAJA COAST. SOME WEAK MID LEVEL CLOUD
ENHANCEMENT ON IR...WE`LL CONTINUE WITH OUR FORECAST OF A FEW LIGHT
SHOWERS / SPRINKLES TODAY MAINLY SOUTH AND SOUTHWEST OF TUCSON EVEN
AS THE LATEST HRRR RUNS KEEP MEASURABLE PRECIP JUST SOUTH OF THE
BORDER (EMPHASIS ON THE "LIGHT" PART).
THE NORTHERN AREA OF THE RIDGE AXIS WILL DAMPEN AND PHASE EASTWARD
OVER THE NEXT 72 HOURS WITH REORIENTATION ASSOCIATED WITH AN ANCHOR
FROM MEXICO INTO THE PLAINS AND MISSISSIPPI VALLEY LATE IN THE
WEEKEND. AS THIS HAPPENS THE RAPIDLY FILLING REMNANT CIRCULATION OFF
THE NORTHER BAJA COAST WILL KICK ACROSS THE AREA SUNDAY INTO MONDAY.
NOT A LOT OF MOISTURE OR DYNAMICS ASSOCIATED WITH IT...BUT COULD
AGAIN BRING A FEW LIGHT SHOWERS INTO THE PICTURE.
PATTERN CHANGE BEGINS NEXT WEEK WITH A STRONG MEAN TROUGH POSITION
BUILDING WITH BROAD BASED SUPPORT IN THE EASTERN PACIFIC AND WEST
COAST. NOT SURE IF WE WILL SEE MUCH OF A SPLIT THIS FAR SOUTH
YET...BUT IT SHOULD SERVE NICELY TO KNOCK TEMPERATURES BACK TO NEAR
CLIMO NEXT WEEK ALONG WITH A FEW BREEZY AFTERNOONS.
&&
.AVIATION...SCT-BKN CLOUDS AROUND 5-9K FT AGL MAINLY SOUTH TO
SOUTHWEST OF KTUS THRU TONIGHT OR 19/09Z. SLIGHT CHANCE OF -SHRA
UNTIL 19/01Z. SURFACE WIND GENERALLY LESS THAN 10 KTS WITH NORMAL
DIURNAL TRENDS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...CONTINUED DRY AND UNSEASONABLY WARM FOR MOST OF THE
AREA INTO THE WEEKEND. NORMAL DIURNAL WIND TRENDS. MOISTURE FROM THE
TROPICS WILL BRING INCREASED CLOUDS AND PERHAPS A FEW LIGHT SHOWERS
MAINLY SOUTH AND WEST OF TUCSON TODAY...ALONG WITH A BRIEF INCREASE
IN RH VALUES.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
402 AM MDT THU OCT 18 2012
.SHORT TERM...
(TODAY AND TONIGHT)
SO FAR TEMPS OVR THE SERN PLAINS HAVE NOT GONE BELOW FREEZING AND
HAVE BEEN IN THE MID AND UPR 30S...BUT DEW POINTS REMAIN QUITE LOW
AND THERE IS STILL TIME FOR TEMPS TO FALL BELOW FREEZING THIS
MORNING. THUS WL LEAVE THE FREEZE WARNING IN EFFECT.
MAIN CONCERN TODAY IS THE POTENTIAL FOR RED FLAG CONDITIONS. WITH A
DRY AIR MASS IN PLACE OVR THE AREA...DEW POINTS TODAY WL BE QUITE
LOW AND MIN RH VALUES ARE EXPECTED TO BE BELOW 15 PERCENT AT THE
LOWER ELEVATIONS. BRISK DRY NW FLOW WL BE FOUND OVR THE AREA
TODAY...ALTHOUGH GENERALLY NOT QUITE AS STRONG AS YESTERDAY IN MOST
AREAS. THE STRONGEST GRADIENT WL BE OVR THE FAR SERN PLAINS...AND
IT LOOKS LIKE GUSTS WL MEET RED FLAG CRITERIA THIS AFTERNOON OVR
KIOWA COUNTY AND A GOOD PORTION OF PROWERS COUNTY...SO WL ISSUE RED
FLAG WARNING. THE HRRR AND LOCAL WRF ARE SHOWING GUSTS ALSO MEETING
CRITERIA OVR NRN EL PASO COUNTY...MAINLY EAST OF THE INTERSTATE SO
WL ALSO ISSUE A WARNING FOR THIS AREA. THERE ARE TWO OTHER AREAS OF
CONCERN...THE FAR EASTERN AREAS OF SRN EL PASO COUNTY (FIRE ZONE
227) AND THE NRN PORTIONS OF THE SAN LUIS VALLEY (FIRE ZONE
224)...WHERE GUSTS ARE ALSO EXPECTED TO REACH RED FLAG WARNING
CRITERIA THIS AFTERNOON. THE PORTIONS OF THESE FIRE ZONES WHERE THE
GUSTS WL PROBABLY MEET CRITERIA SEEM TOO LOCALIZED TO ISSUE RED FLAG
WARNINGS FOR THE ENTIRE ZONE...SO WL NOT ISSUE A HIGHLIGHT AT THIS
TIME.
FOR TONIGHT...THE WEATHER WL REMAIN DRY WITH LITTLE IF ANY CLOUDS.
SOME AREAS...MAINLY ALONG THE ARKANSAS RIVER VALLEY...MAY AGAIN SEE
LOW TEMPS FALL BELOW 32 DEGREES. WL HAVE TO WAIT AN SEE IF WE GET A
FREEZE THIS MORNING TO SEE IF A HIGHLIGHT MAY BE NEEDED TONIGHT.
.LONG TERM...
(FRIDAY THROUGH WEDNESDAY)
...WARM AND DRY THROUGH THE WEEKEND...
FRIDAY-SUNDAY...MODELS REMAIN IN GOOD AGREEMENT THROUGH THE WEEKEND
AS MODERATING NORTHWEST FLOW ALOFT ACROSS THE REGION ON FRIDAY
BECOMES MORE WEST TO SOUTHWEST SATURDAY AND INCREASES AGAIN ON
SUNDAY WITH PAC NORTHWEST ENERGY DIGGING ACROSS THE GREAT BASIN AND
NORTHERN TIER OF STATES. MODELS ALSO INDICATING THE WEAKENING
REMNANTS OF POST TROPICAL SYSTEM PAUL LIFTING OUT ACROSS THE
DESERT SOUTHWEST ON SUNDAY. WARMING ALOFT PROGGED ACROSS THE AREA
FRIDAY AND SATURDAY ALONG WITH DOWNSLOPE FLOW WILL ALLOW FOR
TEMPERATURES TO WARM BACK TO ABOVE SEASONAL AVERAGES...ESPECIALLY
ON SATURDAY WITH HIGHS EXPECTED TO BE IN THE 70S AND 80S ACROSS
THE EASTERN PLAINS WITH MAINLY 50S AND 60S ACROSS THE HIGHER
TERRAIN. DEVELOPING DOWNSLOPE FLOW AND THE WARMING ALOFT WILL ALSO
ALLOW FOR WARMER OVERNIGHT LOWS...ESPECIALLY OVER AND NEAR THE
HIGHER TERRAIN. A WEAK NORTHERLY SURGE/COLD FRONT AND COOLING
ALOFT AHEAD OF PAC NORTHWEST TROUGH WILL BRING ONLY SLIGHTLY
COOLER TEMPERATURES ACROSS THE AREA ON SUNDAY.
MONDAY-WEDNESDAY...LESSER CONFIDENCE FORECAST...ESPECIALLY FOR THE
MIDDLE OF THE WEEK AND BEYOND...WITH MODELS DIFFERING ON AMPLITUDE
AND MOVEMENT OF PACIFIC ENERGY DIGGING INTO THE GREAT BASIN AND
ROCKIES. MODELS DO AGREE THAT THE REMNANTS OF THE TROPICAL SYSTEM TO
REMAIN WELL SOUTH OF THE AREA AS IT CONTINUES TO WEAKEN AND LIFT OUT
ACROSS SOUTHERN NEW MEXICO AND THE SOUTHERN HIGH PLAINS.
THE LATEST GFS REMAINS THE DEEPEST SOLUTION WITH MODERATE AND MAINLY
DRY SOUTHWEST FLOW ACROSS THE STATE THROUGH WEDNESDAY WITH A STAND
UP PACIFIC COLD FRONT MOVING ACROSS THE STATE WEDNESDAY AND WEDNESDAY
NIGHT. THE ECMWF IS FASTER AND LESS AMPLIFIED WITH THE SYSTEM AND
MOVES THE FRONT ACROSS THE AREA MONDAY NIGHT AND TUESDAY WITH A
SECONDARY SURGE OF COLD AIR MOVING ACROSS THE AREA WEDNESDAY NIGHT
AND THURSDAY. AT ANY RATE...PATTERN WOULD SUGGEST BEST CHANCES OF
PRECIP TO BE ACROSS THE HIGHER TERRAIN ALONG AND WEST OF THE
CONTDVD WITH TEMPERATURES SLOWLY COOLING BACK TO AT OR BELOW
SEASONAL AVERAGES BE THE MIDDLE OF THE WEEK. -MW
&&
.AVIATION...
WITH DRY NW FLOW IN PLACE...FEW IS ANY CLOUDS ARE EXPECTED TODAY AND
TONIGHT AND THUS VFR CONDITIONS WL BE FOUND ACRS THE AREA. SOME
AREAS WL SEE BREEZY NORTHWEST WINDS TODAY. KCOS COULD SEE GUSTS NR
20 KTS THIS AFTERNOON...WITH WINDS AT KALS AND KPUB EXPECTED TO NOT
BE QUITE AS STRONG.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 8 AM MDT THIS MORNING FOR COZ083-086-088-
093>099.
RED FLAG WARNING FROM NOON TODAY TO 7 PM MDT THIS EVENING FOR
COZ226-234-236.
&&
$$
28/23
AREA FORECAST DISCUSSION
NWS DENVER CO
322 AM MDT THU OCT 18 2012
.SHORT TERM...STG NWLY FLOW ALOFT WIL CONTINUE OVER THE AREA TODAY
WITH A VERY DRY AIRMASS IN PLACE. BIGGEST CONCERN FROM LATE MORNING
THRU THE MID AFTN HOURS WILL BE HIGH WND POTENTIAL OVER THE FAR NERN
PLAINS. 50-60 KT FLOW IN THE 800-700 MB LAYER COULD MIX DOWN TO THE
SFC AND PRODUCE SOME WIND GUSTS TO 60 MPH MAINLY EAST OF NEW RAYMER TO
AKRON LINE FM 15Z-21Z. MEANWHILE WITH GUSTY WINDS AND LOW HUMIDITY
LEVELS BY EARLY AFTN WILL CONTINUE WITH RED FLAG WARNING AND
EXPAND IT A BIT FURTHER WEST AND SOUTH AS WELL OVER NERN CO. HIGHS
THIS AFTN LOOK SIMILAR TO WED AS 850-700 MM TEMPS DO NOT CHANGE
MUCH.
FOR TONIGHT WINDS WILL REMAIN GUSTY OVER THE FAR NERN PLAINS THROUGH
THE EARLY EVENING HOURS HOWEVER SPEEDS SHOULD BE BELOW WARNING
CRITERIA.
.LONG TERM...UPPER RIDGING IS PROGGED ACROSS COLORADO FRIDAY INTO
SATURDAY WITH WEAKER NORTHWESTERLY FLOW ALOFT. ON SATURDAY...THE
FLOW ALOFT IS ZONAL...THEN SOUTHWESTERLY BY LATE SATURDAY NIGHT.
THE SYNOPTIC SCALE ENERGY IS BENIGN FRIDAY THROUGH SATURDAY NIGHT.
THE LOW LEVEL PRESSURE AND WIND FIELDS SHOW WEAK TROUGHING EAST OF
THE MOUNTAINS ALL FOUR PERIODS. NORMAL DIURNAL PATTERNS MAY WIN
OUT BUT THERE COULD BE SOME DOWNSLOPING AT TIMES. WINDS WILL
DEFINITELY BE LESS SIGNIFICANT AS THEY THEY HAVE BEEN LATELY.
MOISTURE-WISE...THERE IS SOME NOW AND AGAIN PROGGED IN THE UPPER
LEVELS ALL FOUR PERIODS...BUT THE LOWER AND MID LEVELS ARE QUITE
DRY. `PRECIPITABLE WATER VALUES ARE IN THE 0.20 TO 0.35 INCH RANGE
ALL FOUR PERIODS. THERE IS NO MEASURABLE PRECIPITATION PROGGED ON
THE QPF FIELDS FRIDAY THROUGH SATURDAY NIGHT. NO POPS. WINDS
SHOULD NOT BE AN ISSUE. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 4-8 C
WARMER THAN TODAY`S. SATURDAY`S WARM-UP ANOTHER 1-3 C OVER
FRIDAY`S. MOS GUIDANCE VALUES ARE INFLATED AGAIN. FOR THE LATER
DAYS...SUNDAY THROUGH WEDNESDAY...MODELS BASICALLY HAVE ZONAL FLOW
ALOFT ON SUNDAY...THEN SOUTHWESTERLY LATE SUNDAY NIGHT THROUGH
WEDNESDAY. THE GFS HAS A WEAK UPPER TROUGH TO MOVE ACROSS SUNDAY
AFTERNOON...THE ECMWF DOES NOT. WIND SPEEDS ALOFT ARE MODERATE ON
SUNDAY THROUGH MONDAY NIGHT...THEN THEY INCREASE. BY WEDNESDAY...
SPEEDS OVER THE CWA ARE AROUND 100 KNOTS AT JET LEVEL...WITH A JET
MAX MOVING INTO NORTHWEST COLORADO BY WEDNESDAY EVENING ACCORDING TO
THE GFS. ON WEDNESDAY...THE GFS HAS A BROAD MEAN TROUGH DEEPENING
OVER THE WESTERN UNITED STATES. THE ECMWF SHOWS A MORE FLAT
TROUGH. MOISTURE IS POOR...BUT INCREASES A BIT LATER ON WEDNESDAY.
TEMPERATURES ARE ABOVE NORMALS.
&&
.AVIATION...WITH NWLY FLOW COMING OFF THE CHEYENNE RIDGE CURRENTLY
HAVE AN LONGMONT ANTICYCLONE IN PLACE NEAR DENVER. THE HRRR AND TO
SOME EXTENT THE RAP HAVE THIS FEATURE CENTERED OVER SWRN WELD COUNTY
BY MIDDAY. AS A RESULT WINDS EARLY THIS MORNING HAVE BEEN SELY
WHICH SHOULD SHIFT TO MORE SLY BY 12Z. BY 18Z WINDS SHOULD BECOME
MORE NNWLY WITH INCREASING SPEEDS BY EARLY AFTN. SOME GUSTS IN THE
25-30 KT RANGE WILL BE POSSIBLE THRU LATE AFTN. WINDS SHOULD
GRADUALLY DECREASE BY 00Z AND THEN BECOME MORE WSW AFTER SUNSET AND
THEN SSW BY 06Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING FROM 9 AM THIS MORNING TO 6 PM MDT THIS
EVENING FOR COZ042-048>051.
RED FLAG WARNING FROM NOON TODAY TO 6 PM MDT THIS EVENING FOR
COZ238-241>251.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION...UPDATE
NWS TAMPA BAY RUSKIN FL
550 AM EDT THU OCT 18 2012
.UPDATE...
EXTENDED THE SLIGHT CHANCE POP FOR A FEW SHOWERS ALONG THE COAST
NORTHWARD TO THE TAMPA BAY AREA AREA FOR THE MORNING HOURS. RADAR
SHOWS A SHOWERS HAVE BEEN ABLE TO TAKE ADVANTAGE OF THE LAND BREEZE
AND SOME SHALLOW MOISTURE BELOW 10KFT. A FEW OF THESE SHOWERS MAY
MIGRATE BACK TO THE BEACHES DURING THE NEXT FEW HOURS BEFORE DAYTIME
HEATING SHUTS DOWN THE LAND BREEZE CIRCULATION.
&&
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED...AND STILL
AMPLIFYING UPPER LEVEL PATTERN OVER THE CONUS. PATTERN IS
HIGHLIGHTED BY A LONGWAVE TROUGH AND DEEP UPPER LOW OVER THE CENTRAL
PORTION OF THE COUNTRY. THIS TROUGH/UPPER LOW WILL CONTINUE TO
SHARPEN AND DIG SOUTHWARD AS IT MIGRATES OVER THE EASTERN STATES
DURING THE NEXT 24 HOURS. CURRENTLY CLOSER TO HOME WE FIND OUR
REGION STILL UNDER DEEP LAYER SYNOPTIC SUBSIDENCE IN THE WAKE OF THE
SHORTWAVE THE BROUGHT THE CLOUDS AND SHOWERS TO THE REGION ON
WEDNESDAY. THE UPPER FLOW OVERHEAD WILL BECOME INCREASINGLY CYCLONIC
ONCE AGAIN LATER TODAY INTO FRIDAY AS WE COME UNDER THE INFLUENCE OF
THE EASTERN U.S. TROUGH.
AT THE SURFACE...FAIRLY WEAK GRADIENT IN PLACE ACROSS THE FORECAST
AREA THIS MORNING BETWEEN A SUBTLE SURFACE TROUGH TOWARD THE KEYS/FL
STRAITS...AND A WELL DEFINED COLD FRONT CROSSING THE TN/LOWER MS
VALLEYS. THIS FRONT IS SUPPORTING A SQUALL LINE OF STRONG/SEVERE
STORMS ALONG IT THIS MORNING. ALTHOUGH SOME SHOWERS ACTIVITY IS
ANTICIPATED WITH THIS FRONT ONCE IT EVENTUALLY ARRIVES IN OUR AREA
FRIDAY/FRIDAY NIGHT...SEVERE WEATHER IS NOT EXPECTED THIS FAR SOUTH.
REGIONAL RADARS ALSO SHOW SOME SHOWER/STORM ACTIVITY DOWN TOWARD THE
FL KEYS IN ASSOCIATED WITH THE FOCUS ALONG THE SURFACE TROUGH.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY...LARGE SYNOPTIC TROUGH WILL CONTINUE TO BUILD EASTWARD AND
ALONG THE NORTHERN GULF COAST. NOT GOING TO SEE MUCH INFLUENCE FROM
THIS FEATURE DURING THE DAYLIGHT HOURS AS NO HEIGHT FALLS ARE
FORECAST TO ARRIVE UNTIL TONIGHT/FRIDAY MORNING. THE LACK OF ANY
SYNOPTIC FORCING AND GENERALLY DRY AIR ALOFT OVER THE MAJORITY OF
THE AREA WILL HELP PROVIDE A DRY AND WARM FORECAST. THERE ARE SOME
INDICATION THAT THE WEAK SURFACE TROUGH OVER SOUTH FLORIDA WILL
SLOWLY MIGRATE NORTHWARD DURING THE DAY AND MAKE ENOUGH PROGRESS TO
RESULT IN A FEW SHOWERS/STORMS AS FAR NORTH AS
LEE/CHARLOTTE/DESOTO/HIGHLANDS COUNTIES BY THIS AFTERNOON. NOT
ANTICIPATING A WHOLE LOT OF ACTIVITY AND WILL KEEP POPS 20-25%. ANY
FURTHER NORTH AND RAIN CHANCES WILL BE 10% OR LESS. HIGH TEMPS REACH
INTO THE MIDDLE/UPPER 80S FOR MOST AREAS. DEVELOPING FLOW OFF THE
NOW RELATIVELY COOLER COASTAL WATERS SHOULD HELP KEEP THE IMMEDIATE
COAST IN THE LOWER 80S (ESPECIALLY THE NATURE COAST).
TONIGHT...SURFACE COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST.
GUIDANCE CONSENSUS SHOWS THE FRONT REACHING THE FL BIG BEND REGION
BY SUNRISE FRIDAY MORNING. DUE TO A LACK OF AVAILABLE MOISTURE AND
WEAK SYNOPTIC FORCING...WHATEVER SHOWERS THIS FRONT CONTAINS WILL BE
PRIMARILY FORCED BY THE LOW LEVEL FOCUS AND CONFINED NEAR THE
BOUNDARY. WITH THIS IN MIND WILL BRING IN SLIGHT CHANCE POPS FOR
LEVY COUNTY IN THE PRE-DAWN HOURS. ONSHORE FLOW MAY ALSO PROVIDE A
SLIGHT CHANCE FOR A SHOWER OR 2 DOWN TOWARD THE SUNCOAST...BUT THE
OVERNIGHT WILL BE GENERALLY DRY FOR THESE ZONES.
FRIDAY/FRIDAY NIGHT...UPPER TROUGH CONTINUES TO EVOLVE WITH SOME
WEAK HEIGHT FALLS FINALLY ARRIVING. THE SURFACE FRONT WILL BE A SLOW
MOVER AT THIS POINT AS IT AWAITS A FINAL SYNOPTIC PUSH LATE IN THE
DAY/FRIDAY NIGHT. BEST CHANCES FOR SCT SHOWERS WITH THE FRONT WILL
REMAIN NORTH OF TAMPA BAY...AND ESPECIALLY NORTH OF THE BROOKSVILLE
AREA. ALTHOUGH THE BEST CHANCES FOR ANY ORGANIZED SHOWER ACTIVITY
WILL BE FOR THESE NORTHERN ZONES...CAN NOT RULE OUT A FEW ISOLATED
SHOWERS FOR THE REST OF FORECAST AREA EITHER UNDERNEATH A BROAD
REGIME OF DEEP LAYER QG FORCING. A FINAL AND MORE DEFINED SHORTWAVE
ROUNDING THE BASE OF THE MAIN TROUGH FRIDAY EVE/NIGHT WILL PROVIDE
THE MASS FIELDS TO ACCELERATE THE FRONT SOUTHWARD. DESPITE BETTER
SYNOPTIC/QG FORCING BY THIS TIME...MOISTURE WILL BE VERY LACKING AND
ONLY SUPPORT SLIGHT CHANCE/ISOLATED SHOWER WORDING. GIVING SOME
WEIGHT TO THE NAM/SREF WILL BEGIN TO END SHOWERS FROM NORTH TO SOUTH
AFTER MIDNIGHT...HOWEVER IF THE GFS ENDS UP VERIFYING THEN THE
DRYING PROCESS WILL BEGIN AND END EVEN FASTER.
SATURDAY...SURFACE COLD FRONT QUICKLY EXITS TO OUR SOUTH EARLY IN
THE MORNING. KEEPING A SLIGHT CHANCE POP IN THE GRIDS SOUTH OF THE
I-4 CORRIDOR THROUGH MID-MORNING...HOWEVER AS MENTIONED ABOVE...
THESE SHOWERS MAY VERY WELL NEED TO BE REMOVED WITH FUTURE
FORECASTS. HIGH PRESSURE WILL QUICKLY BUILD IN FROM THE WEST AND
PROVIDE A GENERALLY DRY AND SEASONABLE DAY UNDER MOSTLY TO PARTLY
SUNNY SKIES. AFTERNOON HIGH TEMPS WILL RANGE FROM THE LOWER 80S
NORTH TO THE MID 80S SOUTH.
&&
.LONG TERM (SATURDAY NIGHT THROUGH NEXT WEDNESDAY)...
HIGH PRESSURE BEHIND THE COLD FRONT WILL BE DUE NORTH OF THE REGION
SATURDAY NIGHT WITH A NORTHERLY DRAINAGE FLOW EXPECTED SUNDAY
MORNING. WITH CLEAR SKIES OVERHEAD...EXPECT FAIRLY GOOD RADIATIONAL
COOLING WHICH WILL ALLOW TEMPERATURES TO FALL TO NEAR 50 DEGREES
OVER THE NATURE COAST...AND INTO THE 50S TO NEAR 60 FOR THE REST OF
THE REGION AWAY FROM THE COAST.
SUNDAY THROUGH WEDNESDAY WILL FEATURE A SLOW WARMING TREND AS
SURFACE HIGH PRESSURE SETTLES IN TO THE NORTH OF THE AREA WHILE AN
UPPER-LEVEL RIDGE BUILDS FROM THE WESTERN GULF...NORTHEASTWARD
TOWARD THE SOUTHEASTERN STATES. WHILE WE CAN NOT REALLY RULE OUT A
SHOWER OR TWO AT TIMES...THE ATMOSPHERE LOOKS VERY DRY AND WILL
LEAVE OUT ANY MENTION OF PRECIPITATION AT THIS TIME.
TEMPERATURES WILL START OFF NEAR NORMAL ON SUNDAY...THEN BEGIN TO
RUN A COUPLE DEGREES ABOVE NORMAL AGAIN FOR THE FIRST HALF OF THE
NEXT WORK WEEK.
&&
.AVIATION...
SOME PATCHY FOG POSSIBLE TOWARD SUNRISE MAINLY AROUND PGD AND LAL.
OTHERWISE...VFR CONDITIONS NEXT 24 HOURS.
&&
.MARINE...
A WEAK GRADIENT WILL KEEP WINDS AND SEAS LOW OVER THE EASTERN GULF
TODAY. A COLD FRONT WILL APPROACH AND MOVE INTO THE NORTHERN MARINE
ZONES FRIDAY BEFORE QUICKLY MOVING SOUTH OF THE REGION FRIDAY NIGHT
AND EARLY SATURDAY. HIGH PRESSURE WILL BUILD NORTH OF THE FORECAST
WATERS IN THE WAKE OF THIS FRONT AND LEAD TO PERIODS OF CAUTIONARY
LEVEL EASTERLY WINDS BY LATER SUNDAY INTO THE EARLY PORTION OF NEXT
WEEK.
&&
.FIRE WEATHER...
A COLD FRONT WILL APPROACH THE REGION TODAY AND TONIGHT AND THEN
MOVE THROUGH THE FLORIDA PENINSULA BY EARLY SATURDAY. DRIER AIR WILL
ARRIVE IN THE WAKE OF THIS FRONT FOR SATURDAY AFTERNOON. THERE IS
STILL SOME UNCERTAINTY IN THE DEGREE OF DRY AIR FOR SATURDAY...
ESPECIALLY SOUTH OF THE I-4 CORRIDOR...HOWEVER A PERIOD OF
CRITICALLY LOW RELATIVE HUMIDITY IS LIKELY NORTH OF I-4 WITH NEAR
CRITICAL LEVELS OF RELATIVE HUMIDITY FURTHER SOUTH. DISPERSION
INDICES ARE ALSO CURRENTLY FORECAST TO BE NEAR 75 TO THE NORTH OF
TAMPA BAY SATURDAY AFTERNOON. IF THIS TREND CONTINUES...THEN FIRE
WEATHER WATCHES MAY BECOME NECESSARY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 85 70 86 68 / 10 10 10 20
FMY 88 71 88 71 / 30 20 20 20
GIF 89 67 88 64 / 10 10 20 20
SRQ 85 70 85 68 / 10 10 10 20
BKV 88 64 86 63 / 10 10 20 20
SPG 85 72 84 72 / 10 10 10 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
410 AM EDT THU OCT 18 2012
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED...AND STILL
AMPLIFYING UPPER LEVEL PATTERN OVER THE CONUS. PATTERN IS
HIGHLIGHTED BY A LONGWAVE TROUGH AND DEEP UPPER LOW OVER THE CENTRAL
PORTION OF THE COUNTRY. THIS TROUGH/UPPER LOW WILL CONTINUE TO
SHARPEN AND DIG SOUTHWARD AS IT MIGRATES OVER THE EASTERN STATES
DURING THE NEXT 24 HOURS. CURRENTLY CLOSER TO HOME WE FIND OUR
REGION STILL UNDER DEEP LAYER SYNOPTIC SUBSIDENCE IN THE WAKE OF THE
SHORTWAVE THE BROUGHT THE CLOUDS AND SHOWERS TO THE REGION ON
WEDNESDAY. THE UPPER FLOW OVERHEAD WILL BECOME INCREASINGLY CYCLONIC
ONCE AGAIN LATER TODAY INTO FRIDAY AS WE COME UNDER THE INFLUENCE OF
THE EASTERN U.S. TROUGH.
AT THE SURFACE...FAIRLY WEAK GRADIENT IN PLACE ACROSS THE FORECAST
AREA THIS MORNING BETWEEN A SUBTLE SURFACE TROUGH TOWARD THE KEYS/FL
STRAITS...AND A WELL DEFINED COLD FRONT CROSSING THE TN/LOWER MS
VALLEYS. THIS FRONT IS SUPPORTING A SQUALL LINE OF STRONG/SEVERE
STORMS ALONG IT THIS MORNING. ALTHOUGH SOME SHOWERS ACTIVITY IS
ANTICIPATED WITH THIS FRONT ONCE IT EVENTUALLY ARRIVES IN OUR AREA
FRIDAY/FRIDAY NIGHT...SEVERE WEATHER IS NOT EXPECTED THIS FAR SOUTH.
REGIONAL RADARS ALSO SHOW SOME SHOWER/STORM ACTIVITY DOWN TOWARD THE
FL KEYS IN ASSOCIATED WITH THE FOCUS ALONG THE SURFACE TROUGH.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY...LARGE SYNOPTIC TROUGH WILL CONTINUE TO BUILD EASTWARD AND
ALONG THE NORTHERN GULF COAST. NOT GOING TO SEE MUCH INFLUENCE FROM
THIS FEATURE DURING THE DAYLIGHT HOURS AS NO HEIGHT FALLS ARE
FORECAST TO ARRIVE UNTIL TONIGHT/FRIDAY MORNING. THE LACK OF ANY
SYNOPTIC FORCING AND GENERALLY DRY AIR ALOFT OVER THE MAJORITY OF
THE AREA WILL HELP PROVIDE A DRY AND WARM FORECAST. THERE ARE SOME
INDICATION THAT THE WEAK SURFACE TROUGH OVER SOUTH FLORIDA WILL
SLOWLY MIGRATE NORTHWARD DURING THE DAY AND MAKE ENOUGH PROGRESS TO
RESULT IN A FEW SHOWERS/STORMS AS FAR NORTH AS
LEE/CHARLOTTE/DESOTO/HIGHLANDS COUNTIES BY THIS AFTERNOON. NOT
ANTICIPATING A WHOLE LOT OF ACTIVITY AND WILL KEEP POPS 20-25%. ANY
FURTHER NORTH AND RAIN CHANCES WILL BE 10% OR LESS. HIGH TEMPS REACH
INTO THE MIDDLE/UPPER 80S FOR MOST AREAS. DEVELOPING FLOW OFF THE
NOW RELATIVELY COOLER COASTAL WATERS SHOULD HELP KEEP THE IMMEDIATE
COAST IN THE LOWER 80S (ESPECIALLY THE NATURE COAST).
TONIGHT...SURFACE COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST.
GUIDANCE CONSENSUS SHOWS THE FRONT REACHING THE FL BIG BEND REGION
BY SUNRISE FRIDAY MORNING. DUE TO A LACK OF AVAILABLE MOISTURE AND
WEAK SYNOPTIC FORCING...WHATEVER SHOWERS THIS FRONT CONTAINS WILL BE
PRIMARILY FORCED BY THE LOW LEVEL FOCUS AND CONFINED NEAR THE
BOUNDARY. WITH THIS IN MIND WILL BRING IN SLIGHT CHANCE POPS FOR
LEVY COUNTY IN THE PRE-DAWN HOURS. ONSHORE FLOW MAY ALSO PROVIDE A
SLIGHT CHANCE FOR A SHOWER OR 2 DOWN TOWARD THE SUNCOAST...BUT THE
OVERNIGHT WILL BE GENERALLY DRY FOR THESE ZONES.
FRIDAY/FRIDAY NIGHT...UPPER TROUGH CONTINUES TO EVOLVE WITH SOME
WEAK HEIGHT FALLS FINALLY ARRIVING. THE SURFACE FRONT WILL BE A SLOW
MOVER AT THIS POINT AS IT AWAITS A FINAL SYNOPTIC PUSH LATE IN THE
DAY/FRIDAY NIGHT. BEST CHANCES FOR SCT SHOWERS WITH THE FRONT WILL
REMAIN NORTH OF TAMPA BAY...AND ESPECIALLY NORTH OF THE BROOKSVILLE
AREA. ALTHOUGH THE BEST CHANCES FOR ANY ORGANIZED SHOWER ACTIVITY
WILL BE FOR THESE NORTHERN ZONES...CAN NOT RULE OUT A FEW ISOLATED
SHOWERS FOR THE REST OF FORECAST AREA EITHER UNDERNEATH A BROAD
REGIME OF DEEP LAYER QG FORCING. A FINAL AND MORE DEFINED SHORTWAVE
ROUNDING THE BASE OF THE MAIN TROUGH FRIDAY EVE/NIGHT WILL PROVIDE
THE MASS FIELDS TO ACCELERATE THE FRONT SOUTHWARD. DESPITE BETTER
SYNOPTIC/QG FORCING BY THIS TIME...MOISTURE WILL BE VERY LACKING AND
ONLY SUPPORT SLIGHT CHANCE/ISOLATED SHOWER WORDING. GIVING SOME
WEIGHT TO THE NAM/SREF WILL BEGIN TO END SHOWERS FROM NORTH TO SOUTH
AFTER MIDNIGHT...HOWEVER IF THE GFS ENDS UP VERIFYING THEN THE
DRYING PROCESS WILL BEGIN AND END EVEN FASTER.
SATURDAY...SURFACE COLD FRONT QUICKLY EXITS TO OUR SOUTH EARLY IN
THE MORNING. KEEPING A SLIGHT CHANCE POP IN THE GRIDS SOUTH OF THE
I-4 CORRIDOR THROUGH MID-MORNING...HOWEVER AS MENTIONED ABOVE...
THESE SHOWERS MAY VERY WELL NEED TO BE REMOVED WITH FUTURE
FORECASTS. HIGH PRESSURE WILL QUICKLY BUILD IN FROM THE WEST AND
PROVIDE A GENERALLY DRY AND SEASONABLE DAY UNDER MOSTLY TO PARTLY
SUNNY SKIES. AFTERNOON HIGH TEMPS WILL RANGE FROM THE LOWER 80S
NORTH TO THE MID 80S SOUTH.
&&
.LONG TERM (SATURDAY NIGHT THROUGH NEXT WEDNESDAY)...
HIGH PRESSURE BEHIND THE COLD FRONT WILL BE DUE NORTH OF THE REGION
SATURDAY NIGHT WITH A NORTHERLY DRAINAGE FLOW EXPECTED SUNDAY
MORNING. WITH CLEAR SKIES OVERHEAD...EXPECT FAIRLY GOOD RADIATIONAL
COOLING WHICH WILL ALLOW TEMPERATURES TO FALL TO NEAR 50 DEGREES
OVER THE NATURE COAST...AND INTO THE 50S TO NEAR 60 FOR THE REST OF
THE REGION AWAY FROM THE COAST.
SUNDAY THROUGH WEDNESDAY WILL FEATURE A SLOW WARMING TREND AS
SURFACE HIGH PRESSURE SETTLES IN TO THE NORTH OF THE AREA WHILE AN
UPPER-LEVEL RIDGE BUILDS FROM THE WESTERN GULF...NORTHEASTWARD
TOWARD THE SOUTHEASTERN STATES. WHILE WE CAN NOT REALLY RULE OUT A
SHOWER OR TWO AT TIMES...THE ATMOSPHERE LOOKS VERY DRY AND WILL
LEAVE OUT ANY MENTION OF PRECIPITATION AT THIS TIME.
TEMPERATURES WILL START OFF NEAR NORMAL ON SUNDAY...THEN BEGIN TO
RUN A COUPLE DEGREES ABOVE NORMAL AGAIN FOR THE FIRST HALF OF THE
NEXT WORK WEEK.
&&
.AVIATION...
SOME PATCHY FOG POSSIBLE TOWARD SUNRISE MAINLY AROUND PGD AND LAL.
OTHERWISE...VFR CONDITIONS NEXT 24 HOURS.
&&
.MARINE...
A WEAK GRADIENT WILL KEEP WINDS AND SEAS LOW OVER THE EASTERN GULF
TODAY. A COLD FRONT WILL APPROACH AND MOVE INTO THE NORTHERN MARINE
ZONES FRIDAY BEFORE QUICKLY MOVING SOUTH OF THE REGION FRIDAY NIGHT
AND EARLY SATURDAY. HIGH PRESSURE WILL BUILD NORTH OF THE FORECAST
WATERS IN THE WAKE OF THIS FRONT AND LEAD TO PERIODS OF CAUTIONARY
LEVEL EASTERLY WINDS BY LATER SUNDAY INTO THE EARLY PORTION OF NEXT
WEEK.
&&
.FIRE WEATHER...
A COLD FRONT WILL APPROACH THE REGION TODAY AND TONIGHT AND THEN
MOVE THROUGH THE FLORIDA PENINSULA BY EARLY SATURDAY. DRIER AIR WILL
ARRIVE IN THE WAKE OF THIS FRONT FOR SATURDAY AFTERNOON. THERE IS
STILL SOME UNCERTAINTY IN THE DEGREE OF DRY AIR FOR SATURDAY...
ESPECIALLY SOUTH OF THE I-4 CORRIDOR...HOWEVER A PERIOD OF
CRITICALLY LOW RELATIVE HUMIDITY IS LIKELY NORTH OF I-4 WITH NEAR
CRITICAL LEVELS OF RELATIVE HUMIDITY FURTHER SOUTH. DISPERSION
INDICES ARE ALSO CURRENTLY FORECAST TO BE NEAR 75 TO THE NORTH OF
TAMPA BAY SATURDAY AFTERNOON. IF THIS TREND CONTINUES...THEN FIRE
WEATHER WATCHES MAY BECOME NECESSARY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 85 70 86 68 / 10 10 10 20
FMY 88 71 88 71 / 30 20 20 20
GIF 89 67 88 64 / 10 10 20 20
SRQ 85 70 85 68 / 10 10 10 20
BKV 88 64 86 63 / 10 10 20 20
SPG 85 72 84 72 / 10 10 10 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION...RESENT
NWS TAMPA BAY RUSKIN FL
355 AM EDT THU OCT 18 2012
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED...AND STILL
AMPLIFYING UPPER LEVEL PATTERN OVER THE CONUS. PATTERN IS
HIGHLIGHTED BY A LONGWAVE TROUGH AND DEEP UPPER LOW OVER THE CENTRAL
PORTION OF THE COUNTRY. THIS TROUGH/UPPER LOW WILL CONTINUE TO
SHARPEN AND DIG SOUTHWARD AS IT MIGRATES OVER THE EASTERN STATES
DURING THE NEXT 24 HOURS. CURRENTLY CLOSER TO HOME WE FIND OUR
REGION STILL UNDER DEEP LAYER SYNOPTIC SUBSIDENCE IN THE WAKE OF THE
SHORTWAVE THE BROUGHT THE CLOUDS AND SHOWERS TO THE REGION ON
WEDNESDAY. THE UPPER FLOW OVERHEAD WILL BECOME INCREASINGLY CYCLONIC
ONCE AGAIN LATER TODAY INTO FRIDAY AS WE COME UNDER THE INFLUENCE OF
THE EASTERN U.S. TROUGH.
AT THE SURFACE...FAIRLY WEAK GRADIENT IN PLACE ACROSS THE FORECAST
AREA THIS MORNING BETWEEN A SUBTLE SURFACE TROUGH TOWARD THE KEYS/FL
STRAITS...AND A WELL DEFINED COLD FRONT CROSSING THE TN/LOWER MS
VALLEYS. THIS FRONT IS SUPPORTING A SQUALL LINE OF STRONG/SEVERE
STORMS ALONG IT THIS MORNING. ALTHOUGH SOME SHOWERS ACTIVITY IS
ANTICIPATED WITH THIS FRONT ONCE IT EVENTUALLY ARRIVES IN OUR AREA
FRIDAY/FRIDAY NIGHT...SEVERE WEATHER IS NOT EXPECTED THIS FAR SOUTH.
REGIONAL RADARS ALSO SHOW SOME SHOWER/STORM ACTIVITY DOWN TOWARD THE
FL KEYS IN ASSOCIATED WITH THE FOCUS ALONG THE SURFACE TROUGH.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY...LARGE SYNOPTIC TROUGH WILL CONTINUE TO BUILD EASTWARD AND
ALONG THE NORTHERN GULF COAST. NOT GOING TO SEE MUCH INFLUENCE FROM
THIS FEATURE DURING THE DAYLIGHT HOURS AS NO HEIGHT FALLS ARE
FORECAST TO ARRIVE UNTIL TONIGHT/FRIDAY MORNING. THE LACK OF ANY
SYNOPTIC FORCING AND GENERALLY DRY AIR ALOFT OVER THE MAJORITY OF
THE AREA WILL HELP PROVIDE A DRY AND WARM FORECAST. THERE ARE SOME
INDICATION THAT THE WEAK SURFACE TROUGH OVER SOUTH FLORIDA WILL
SLOWLY MIGRATE NORTHWARD DURING THE DAY AND MAKE ENOUGH PROGRESS TO
RESULT IN A FEW SHOWERS/STORMS AS FAR NORTH AS
LEE/CHARLOTTE/DESOTO/HIGHLANDS COUNTIES BY THIS AFTERNOON. NOT
ANTICIPATING A WHOLE LOT OF ACTIVITY AND WILL KEEP POPS 20-25%. ANY
FURTHER NORTH AND RAIN CHANCES WILL BE 10% OR LESS. HIGH TEMPS REACH
INTO THE MIDDLE/UPPER 80S FOR MOST AREAS. DEVELOPING FLOW OFF THE
NOW RELATIVELY COOLER COASTAL WATERS SHOULD HELP KEEP THE IMMEDIATE
COAST IN THE LOWER 80S (ESPECIALLY THE NATURE COAST).
TONIGHT...SURFACE COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST.
GUIDANCE CONSENSUS SHOWS THE FRONT REACHING THE FL BIG BEND REGION
BY SUNRISE FRIDAY MORNING. DUE TO A LACK OF AVAILABLE MOISTURE AND
WEAK SYNOPTIC FORCING...WHATEVER SHOWERS THIS FRONT CONTAINS WILL BE
PRIMARILY FORCED BY THE LOW LEVEL FOCUS AND CONFINED NEAR THE
BOUNDARY. WITH THIS IN MIND WILL BRING IN SLIGHT CHANCE POPS FOR
LEVY COUNTY IN THE PRE-DAWN HOURS. ONSHORE FLOW MAY ALSO PROVIDE A
SLIGHT CHANCE FOR A SHOWER OR 2 DOWN TOWARD THE SUNCOAST...BUT THE
OVERNIGHT WILL BE GENERALLY DRY FOR THESE ZONES.
FRIDAY/FRIDAY NIGHT...UPPER TROUGH CONTINUES TO EVOLVE WITH SOME
WEAK HEIGHT FALLS FINALLY ARRIVING. THE SURFACE FRONT WILL BE A SLOW
MOVER AT THIS POINT AS IT AWAITS A FINAL SYNOPTIC PUSH LATE IN THE
DAY/FRIDAY NIGHT. BEST CHANCES FOR SCT SHOWERS WITH THE FRONT WILL
REMAIN NORTH OF TAMPA BAY...AND ESPECIALLY NORTH OF THE BROOKSVILLE
AREA. ALTHOUGH THE BEST CHANCES FOR ANY ORGANIZED SHOWER ACTIVITY
WILL BE FOR THESE NORTHERN ZONES...CAN NOT RULE OUT A FEW ISOLATED
SHOWERS FOR THE REST OF FORECAST AREA EITHER UNDERNEATH A BROAD
REGIME OF DEEP LAYER QG FORCING. A FINAL AND MORE DEFINED SHORTWAVE
ROUNDING THE BASE OF THE MAIN TROUGH FRIDAY EVE/NIGHT WILL PROVIDE
THE MASS FIELDS TO ACCELERATE THE FRONT SOUTHWARD. DESPITE BETTER
SYNOPTIC/QG FORCING BY THIS TIME...MOISTURE WILL BE VERY LACKING AND
ONLY SUPPORT SLIGHT CHANCE/ISOLATED SHOWER WORDING. GIVING SOME
WEIGHT TO THE NAM/SREF WILL BEGIN TO END SHOWERS FROM NORTH TO SOUTH
AFTER MIDNIGHT...HOWEVER IF THE GFS ENDS UP VERIFYING THEN THE
DRYING PROCESS WILL BEGIN AND END EVEN FASTER.
SATURDAY...SURFACE COLD FRONT QUICKLY EXITS TO OUR SOUTH EARLY IN
THE MORNING. KEEPING A SLIGHT CHANCE POP IN THE GRIDS SOUTH OF THE
I-4 CORRIDOR THROUGH MID-MORNING...HOWEVER AS MENTIONED ABOVE...
THESE SHOWERS MAY VERY WELL NEED TO BE REMOVED WITH FUTURE
FORECASTS. HIGH PRESSURE WILL QUICKLY BUILD IN FROM THE WEST AND
PROVIDE A GENERALLY DRY AND SEASONABLE DAY UNDER MOSTLY TO PARTLY
SUNNY SKIES. AFTERNOON HIGH TEMPS WILL RANGE FROM THE LOWER 80S
NORTH TO THE MID 80S SOUTH.
&&
.LONG TERM (SATURDAY NIGHT THROUGH NEXT WEDNESDAY)...
HIGH PRESSURE BEHIND THE COLD FRONT WILL BE DUE NORTH OF THE REGION
SATURDAY NIGHT WITH A NORTHERLY DRAINAGE FLOW EXPECTED SUNDAY
MORNING. WITH CLEAR SKIES OVERHEAD...EXPECT FAIRLY GOOD RADIATIONAL
COOLING WHICH WILL ALLOW TEMPERATURES TO FALL TO NEAR 50 DEGREES
OVER THE NATURE COAST...AND INTO THE 50S TO NEAR 60 FOR THE REST OF
THE REGION AWAY FROM THE COAST.
SUNDAY THROUGH WEDNESDAY WILL FEATURE A SLOW WARMING TREND AS
SURFACE HIGH PRESSURE SETTLES IN TO THE NORTH OF THE AREA WHILE AN
UPPER-LEVEL RIDGE BUILDS FROM THE WESTERN GULF...NORTHEASTWARD
TOWARD THE SOUTHEASTERN STATES. WHILE WE CAN NOT REALLY RULE OUT A
SHOWER OR TWO AT TIMES...THE ATMOSPHERE LOOKS VERY DRY AND WILL
LEAVE OUT ANY MENTION OF PRECIPITATION AT THIS TIME.
TEMPERATURES WILL START OFF NEAR NORMAL ON SUNDAY...THEN BEGIN TO
RUN A COUPLE DEGREES ABOVE NORMAL AGAIN FOR THE FIRST HALF OF THE
NEXT WORK WEEK.
&&
.AVIATION...
SOME PATCHY FOG POSSIBLE TOWARD SUNRISE MAINLY AROUND PGD AND LAL.
OTHERWISE...VFR CONDITIONS NEXT 24 HOURS.
&&
.MARINE...
A WEAK GRADIENT WILL KEEP WINDS AND SEAS LOW OVER THE EASTERN GULF
TODAY. A COLD FRONT WILL APPROACH AND MOVE INTO THE NORTHERN MARINE
ZONES FRIDAY BEFORE QUICKLY MOVING SOUTH OF THE REGION FRIDAY NIGHT
AND EARLY SATURDAY. HIGH PRESSURE WILL BUILD NORTH OF THE FORECAST
WATERS IN THE WAKE OF THIS FRONT AND LEAD TO PERIODS OF CAUTIONARY
LEVEL EASTERLY WINDS BY LATER SUNDAY INTO THE EARLY PORTION OF NEXT
WEEK.
&&
.FIRE WEATHER...
A COLD FRONT WILL APPROACH THE REGION TODAY AND TONIGHT AND THEN
MOVE THROUGH THE FLORIDA PENINSULA BY EARLY SATURDAY. DRIER AIR WILL
ARRIVE IN THE WAKE OF THIS FRONT FOR SATURDAY AFTERNOON. THERE IS
STILL SOME UNCERTAINTY IN THE DEGREE OF DRY AIR FOR SATURDAY...
ESPECIALLY SOUTH OF THE I-4 CORRIDOR...HOWEVER A PERIOD OF
CRITICALLY LOW RELATIVE HUMIDITY IS LIKELY NORTH OF I-4 WITH NEAR
CRITICAL LEVELS OF RELATIVE HUMIDITY FURTHER SOUTH. DISPERSION
INDICES ARE ALSO CURRENTLY FORECAST TO BE NEAR 75 TO THE NORTH OF
TAMPA BAY SATURDAY AFTERNOON. IF THIS TREND CONTINUES...THEN FIRE
WEATHER WATCHES MAY BECOME NECESSARY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 85 70 86 68 / 10 10 10 20
FMY 88 71 88 71 / 30 20 20 20
GIF 89 67 88 64 / 10 10 20 20
SRQ 85 70 85 68 / 10 10 10 20
BKV 88 64 86 63 / 10 10 20 20
SPG 85 72 84 72 / 10 10 10 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
338 AM EDT THU OCT 18 2012
.DISCUSSION...
TODAY-TONIGHT...ATLC RIDGE AXIS OVER THE FL STRAITS/NRN BAHAMAS WILL
INTERACT WITH A FRONTAL TROF PUSHING THRU THE DEEP SOUTH TO GENERATE
A STEADY S/SWRLY FLOW THRU THE H100-H70 LYR. EVENING SOUNDINGS SHOW
THE AIRMASS HAS MOISTENED SIGNIFICANTLY OVER THE PAST 24HRS WITH
PWAT VALUES RECOVERING TO 1.3" AT KJAX...1.5" AT KTBW...AND 2.0" AT
KMFL...THANKS LARGELY TO THE DEEP LOW LVL SRLY FLOW...THE USAF 915HZ
PROFILER AT THE CAPE INDICATING 15-20KTS THRU THE H100-H85 LYR.
LATEST RAP ANALYSIS SHOWS A WEAK MID LVL VORT AXIS AND AN AREA OF
DECENT UPR LVL DIVERGENCE ACRS THE S PENINSULA. BOTH ARE EMBEDDED
WITHIN A STRONG ZONAL FLOW PATTERN THAT WILL TAKE THE BULK OF ITS
LIFTING INFLUENCE OFFSHORE RATHER THAN NWD INTO CENTRAL FL.
HOWEVER...ISENTROPIC ANALYSIS DOES SHOW STRONG LIFT THRU THE
310K-315K LYR AS THE ZONAL FLOW BLOWS ACRS A BAND OF ENHANCED
H85-H70 THETA-E AIR...LIKELY THE REMNANTS OF THE WED FROPA. LOW LVL
MOISTURE OVER THE STRAITS AND THE NW CARIB IS PLENTIFUL AND WILL
LIFT NWD UNDER THE INFLUENCE OF THE SRLY LOW/MID LVL FLOW.
THERMODYNAMIC PROFILE REVEALS H85-H70 LAPSE RATES BTWN 5.5-6.5C/KM
OVER MUCH OF ECFL...BUT THESE FLATTEN OUT TO AOB 5.0C/KM THRU THE
H85-H50 LYR. H50 TEMPS ARND -6C EXTEND ACRS MOST OF THE GOMEX.
CANNOT COMPLETELY RULE TSRAS OUT OF THE FCST DUE TO THE LOW LVL
MOISTURE AND THE ISENTROPIC LIFT...BUT THESE WILL BE LIMITED TO THE
SERN CWA AS THE KJAX/KTAE SOUNDINGS INDICATE A SURPRISINGLY STRONG
SUBSIDENCE INVERSION THRU THE H70-H50 LYR THAT WILL LIMIT VERTICAL
MOTION ACRS THE NWRN CWA.
LOW STRATUS CLOUDS OVER THE INTERIOR SHOULD BURN OFF RAPIDLY AFT
SUNRISE. NEAR FULL SUN AND S/SW FLOW WILL ALLOW MAX TEMPS TO WARM
INTO THE M/U80S. WINDS WILL DIMINISH AFT SUNSET BUT ARE NOT EXPECTED
TO DECOUPLE DUE TO THE APPROACHING. LIGHT BUT STEADY S/SW WINDS WILL
KEEP MIN TEMPS IN THE M/U60S INTERIOR...U60S/L70S ALONG THE COAST.
FRI-SAT...LARGE LOW PRESSURE SYSTEM CENTERED OVER LAKE MICHIGAN
REGION EARLY FRIDAY WILL LIFT NEWD INTO SATURDAY. COLD FRONT
TRAILING FROM THIS SYSTEM WILL PUSH THROUGH THE CENTRAL FLORIDA
PENINSULA FRIDAY NIGHT AND BE SOUTH OF THE AREA BY EARLY SATURDAY.
SUFFICIENT MOISTURE AND DAYTIME INSTABILITY AHEAD OF THE FRONT FOR
CHC/SCT SHRA AND ISOLD TSRA DAYTIME FRI WITH SOME ACTIVITY LINGERING
INTO OVERNIGHT HOURS AHEAD OF THE FRONTAL PASSAGE. HIGH PRESSURE
BUILDING IN BEHIND THE BOUNDARY WILL BRING AN END TO THE RAIN
CHANCES AS A SLIGHTLY COOLER AND LESS HUMID AIR MASS MOVES IN FOR
SATURDAY. EXPECT DAYTIME HIGHS IN THE MID/UPPER 80S FRI...THEN
LOWER/MID 80S SATURDAY WITH LOWER DEW POINTS MAKING IT FEEL MORE
COMFORTABLE AS WELL. MORN LOWS IN THE MID 60S NORTH/NEAR 70 SOUTH
FRI AND NEAR 60/LOWER 60S NORTH AND MID/UPPER 60S SOUTH SAT.
SUN-THU...SURFACE HIGH PRESSURE TO THE NORTH BUILDING ALONG THE
EASTERN SEABOARD AND RIDGE ALOFT BUILDING ACROSS THE STATE FROM THE
GULF OF MEXICO INTO EARLY NEXT WEEK. THIS WILL BRING AN ONSHORE FLOW
REGIME TO EC FL WHICH IS EXPECTED TO PERSIST THROUGH THE MIDDLE OF
THE WEEK. PATTERN WILL FAVOR A SLOW INCREASE IN MOISTURE AND TEMPS
MODERATED BY THE ONSHORE FLOW. WILL KEEP POPS BELOW MENTIONABLE
VALUES OVER LAND AREAS BUT SOME LOW POPS FOR COASTAL SHOWERS MAY
BECOME WARRANTED.
&&
.AVIATION...THRU 18/13Z...AREAS MVFR VSBYS/IFR CIGS N OF KISM-KTIX
DUE TO BR AND LOW STRATUS. BTWN 18/13Z-18/18Z...VFR. BTWN
18/18Z-18-20Z...SFC WNDSHFT COASTAL SITES FM SW TO E/SE AOB 10KT
ASSOCD WITH THE EAST COAST SEA BREEZE...VCSH S OF KMLB. BTWN
18/20Z-18/23Z...SFC WNDSHFT INTERIOR SITES FM SW TO S/SE AOB 10KTS
AS THE EAST COAST SEA BREEZE PUSHES INLAND...CHC MVFR SHRAS/SLGT CHC
IFR TSRAS S OF KMLB. BTWN 18/23Z-19/04Z...SLGT CHC MVFR SHRAS S OF
KISM-KTIX. AFT 19/04Z...VFR.
&&
.MARINE...TODAY-TONIGHT...LCL DATA BUOY/C-MAN NETWORK SHOWING SERLY
SFC/BNDRY LYR BREEZE BTWN 15-20KTS N OF CAPE CANAVERAL...10-15KTS S
OF THE CAPE. WINDS WILL DIMINISH TO AOB 10KTS BY AFTN AS A NEW
FRONTAL TROF PUSHES ACRS THE DEEP SOUTH AND INTO THE FL PANHANDLE.
LINGERING SWELLS FROM FORMER T.C. RAFAEL WILL SUBSIDE AS WELL. SEAS
3-4FT NEARSHORE AND 4-5FT OFFSHORE THRU SUNSET...BCMG 2-4FT AREAWIDE
OVERNIGHT. SLGT CHC OF TSRAS MOVG OFFSHORE S OF KMLB THIS AFTN.
WINDS WILL PICK UP OUT OF THE NNW-N FRI NIGHT INTO SAT AS FRONT
PUSHES DOWN THE PENINSULA AND THE ADJACENT ATLANTIC WATERS. ONSHORE
FLOW REGIME DEVELOPING BEHIND THE FRONT SUNDAY THROUGH THE MIDDLE OF
NEXT WEEK WITH HIGH PRESSURE TO THE NORTH BUILDING ALONG THE EASTERN
SEABOARD. THE ONSHORE WINDS INCREASING INTO THE 15-20KT RANGE AND
PERSISTENT ONSHORE FLOW WILL RESULT IN SEA HEIGHTS RISING TO 6-7 FT
OFFSHORE BY THE END OF THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 86 69 85 63 / 10 10 20 20
MCO 88 69 87 66 / 10 10 20 20
MLB 87 71 86 69 / 20 20 30 20
VRB 87 71 87 69 / 30 20 30 30
LEE 87 68 87 64 / 10 10 20 20
SFB 87 68 88 65 / 10 10 20 20
ORL 88 69 88 66 / 10 10 20 20
FPR 87 71 86 69 / 30 20 30 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM....GLITTO
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
330 AM EDT THU OCT 18 2012
.SHORT TERM /TODAY THROUGH FRIDAY/...
NAM/GFS/ECMWF IN DECENT AGREEMENT THROUGH THE SHORT TERM...SO WENT
WITH A GENERAL BLEND FOR MOST ELEMENTS. LARGE MID LEVEL LOW SPINNING
OVER THE US/CANADA BORDER CONTINUES TO DEEPEN AND PROPAGATE
SOUTHEAST /500MB 00Z UA ANALYSIS HAD MORE HEIGHT FALLS DOWNSTREAM OF
THE LOW THAN HEIGHT RISES UPSTREAM/...AS COLD FRONT STRETCHING FROM
THE OCCLUDED SURFACE LOW SWEEPS ACROSS THE MISSISSIPPI VALLEY. THE
MAIN CONCERN FOR THE PERIOD REMAINS CONVECTION TRENDS FOR TODAY.
LINE OF SHOWERS AND THUNDERSTORMS CURRENTLY STRETCHED FROM MIDDLE
TENNESSEE THROUGH ALABAMA AT AFD TIME...WELL AHEAD OF THE COLD
FRONT...AND SHOULD REACH EXTREME NORTHWEST ZONES WITHIN THE HOUR.
INSTABILITY IS MINIMAL WITH NO SBCAPE SHOWING UP IN MESOANALYSIS...
AND MUCAPE VALUES AT BEST AROUND 250 J/KG...SO THE DRIVING FORCE
BEHIND THE CONVECTION IS SIMPLY THE SYNOPTIC SCALE LIFT...OF WHICH
THERE IS PLENTY. MOST HIRES GUIDANCE REALLY BREAKS THE SYSTEM DOWN
AS IT MOVES INTO GEORGIA...THOUGH THE HRRR DOES KEEP SOME SEMBLANCE
OF ORGANIZED CONVECTION. LIGHTNING ACTIVITY HAS DECREASED IN THE
LINE OVER THE LAST HOUR OR SO. SREF GUIDANCE IS HARD-PRESSED TO
BRING ANY CAPE INTO THE AREA UNTIL THIS AFTERNOON.
SO WITH THAT SAID...HAVE SORT OF TAKEN A COMPROMISE BETWEEN
EXTRAPOLATING WHAT IS ALREADY OUT THERE AND THE SUITE OF HIRES
GUIDANCE. BRING CATEGORICAL POPS INTO NORTHWEST GEORGIA OVER THE
NEXT FEW HOURS WITH DEFINITE THUNDER AT THE ONSET...THEN DECREASE
THUNDER WORDING AS PRECIPITATION SPREADS TOWARD THE METRO AREA BY
12Z. BROUGHT ADDITIONAL THUNDER BACK IN THIS AFTERNOON ACROSS
SOUTHERN ZONES AS INSTABILITY INCREASES WITH AFTERNOON HEATING. NO
REAL CONCERN WITH SEVERE WEATHER AS BEST SHEAR WILL REMAIN TO OUR
NORTH AND NORTHEAST TODAY...BUT CANNOT TOTALLY RULE OUT THE
POSSIBILITY OF AN ISOLATED STRONG TO POSSIBLY SEVERE THUNDERSTORM
ACROSS CENTRAL GEORGIA THIS AFTERNOON. GUSTY WINDS WILL BE THE MAIN
THREAT. OTHERWISE...FOR THE MOST PART LOOKS LIKE A QUICK SHOT OF
RAIN...WITH HIGHEST AMOUNTS NORTHWEST POSSIBLY UP TO A HALF INCH.
COLD FRONT SWEEPS THROUGH BEHIND THE AREA OF RAIN...WITH DRIER AIR
MOVING IN BEHIND IT. WHILE MASS FIELDS REMAIN VERY SIMILAR...MORE
DIFFERENCES BEGIN TO CREEP IN BETWEEN THE NAM AND GFS...WITH MET
GUIDANCE REMAINING A LITTLE MORE MOIST AND THUS A LITTLE WARMER
OVERNIGHT...WITH WARMER TEMPS ON FRIDAY AS WELL. AGAIN...LEANED
GENERALLY TOWARD A BLEND BUT LEANED SLIGHTLY ON THE COOLER SIDE. LOW
TEMPS TONIGHT IN SOME AREAS MAY FLIRT WITH THE UPPER 30S. THIS WILL
BE HEAVILY DEPENDENT ON DEWPOINTS...AND LOOKING UPSTREAM BEHIND THE
FRONT THE DEWPOINTS ARE QUITE DRY. OBVIOUSLY SOME MODIFICATION OF
THE AIRMASS CAN BE EXPECTED...BUT EITHER WAY IT LOOKS LIKE TONIGHT
WILL PROBABLY HAVE THE COLDEST TEMPS OF THE SEASON THUS FAR.
OTHER ITEM OF NOTE WILL BE WINDS IN THE MOUNTAINS ON FRIDAY. AS THE
LOW DIGS SOUTHEAST TOWARD THE GREAT LAKES TODAY AND FRIDAY...THERE
MIGHT BE ENOUGH OF A GRADIENT IN THE MOUNTAINS FRIDAY AFTERNOON
BEFORE THE SURFACE HIGH BEGINS TO BUILD IN FOR POSSIBLE WIND
ADVISORY CRITERIA. TOO EARLY AT THIS POINT BUT WILL REEVALUATE WITH
LATER FORECASTS.
TDP
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE LONG TERM LOOKS TO HAVE MUCH LESS ACTIVITY IN STORE THAN THE
SHORT TERM...AS A DRY FORECAST DOMINATED BY HIGH PRESSURE IS ON TAP.
GUIDANCE IS IN GENERAL AGREEMENT WITH A WEAK SHORTWAVE PUSHING
THROUGH THE FORECAST AREA FRIDAY NIGHT AS IT ROTATES AROUND THE
BROAD UPPER CLOSED LOW CENTERED OVER THE GREAT LAKES. HOWEVER...THIS
ENERGY SHOULD BE TOO REMOVED FROM THE MOISTURE FIELD NORTH OF THE
AREA TO TRANSLATE TO ANY PRECIP CHANCES AND THE UPPER TROUGH AXIS
SHOULD BE EAST OF THE AREA BY LATER SATURDAY...THEREFORE WILL KEEP
DRY CONDITIONS AS THE UPPER RIDGE BUILDS IN FOR NEXT WEEK. MEX
GUIDANCE TEMPS CONTINUE TO LOOK TOO COOL SO HAVE RAISED A BIT
BASED ON PREVIOUS TRENDS...KEEPING MUCH OF THE AREA NEAR
SEASONABLE VALUES TO SLIGHTLY ABOVE NORMAL FROM SUNDAY ONWARD.
BAKER
&&
.AVIATION...
06Z UPDATE...
SHRA AND TSRA AHEAD OF COLD FRONT WILL PUSH INTO NW GA 07-08Z...
BUT IS WEAKENING. REMOVED TSRA FROM NORTHERN TAFS...KEEPING -SHRA
INSTEAD. EXPECT AT LEAST A BRIEF PERIOD OF MVFR WITH THE SHRA BUT
LIFTING CIGS BEHIND THE RAIN AS THE LINE MOVES EAST. SE WINDS
AROUND 5KT OR SO TO START THE PERIOD...SHIFTING TO WEST AND
INCREASING AROUND 14Z ATL METRO AREA AND CSG...LATER FOR CSG AND
MCN. MAY SEE SOME LOW-END GUSTS THROUGH THE AFTERNOON. CLEARING
LATE TODAY AND TONIGHT.
//ATL CONFIDENCE...06Z UPDATE...
HIGH ON -SHRA. LOW ON POTENTIAL FOR -TSRA. MEDIUM ON TIMING.
HIGH ON MVFR CIGS...MEDIUM ON TIMING.
HIGH ON WINDS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 72 46 73 47 / 60 10 5 5
ATLANTA 72 51 73 47 / 50 10 0 5
BLAIRSVILLE 66 42 66 40 / 20 5 0 5
CARTERSVILLE 72 40 72 44 / 20 5 0 5
COLUMBUS 79 51 76 49 / 60 10 5 5
GAINESVILLE 69 48 71 46 / 50 5 0 5
MACON 79 47 77 46 / 50 20 5 5
ROME 73 39 71 43 / 20 5 0 5
PEACHTREE CITY 74 41 74 43 / 50 10 0 5
VIDALIA 81 61 79 53 / 30 30 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TDP
LONG TERM....BAKER
AVIATION...TDP
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
148 AM EDT THU OCT 18 2012
.PREV DISCUSSION... /ISSUED 1022 PM EDT WED OCT 17 2012/
UPDATE...
CONTINUE TO MONITOR TRENDS ON IR SATELLITE AND RADAR OF CONVECTION
IN THE MID-SOUTH AS IT ENTERS WESTERN TENNESSEE. FORECAST HAS BEEN
UPDATED TO ACCOUNT FOR EARLIER TIMING OF THIS SYSTEM...ENTERING
NORTH GEORGIA EARLY THURSDAY MORNING. LATEST LOCAL WRF AND
NATIONAL HRRR MODEL GUIDANCE CONTINUES TO INDICATE THAT ACTIVITY
SHOULD BEGIN TO FALL APART AS IT MOVES THROUGH METRO ATLANTA
BETWEEN 08Z AND 10Z THURSDAY MORNING.
AVAILABLE INSTABILITY SHOULD ALLOW THE LINE TO PRODUCE SOME
THUNDERSTORMS IN NORTH GEORGIA TONIGHT. CANNOT RULE OUT AN
ISOLATED EMBEDDED TORNADO AS THIS LINE PUSHES THROUGH...WITH 0-1
KM SHEAR VALUES NEARING 55 KTS...ALTHOUGH THE THREAT OF A STRAIGHT
LINE WIND EVENT IS SLIGHTLY MORE LIKELY GIVEN THE LITTLE
DIRECTIONAL 0-1 KM SHEAR IN NORTH GEORGIA OVERNIGHT ACCORDING TO
THE 22Z HRRR RUN.
RAG/37
PREV DISCUSSION...
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
/ISSUED AT 255 PM EDT WED OCT 17 2012/
UPPER LEVEL FLOW TRANSITIONING FROM A FLAT...NEARLY ZONAL...PATTERN
ACROSS THE CONTINENTAL U.S. TO A RELATIVELY STATIC...HIGH AMPLITUDE
PATTERN AS A STRONG SHORT WAVE DIVING OUT OF CANADA DIGS A DEEP
UPPER LOW INTO THE UPPER MISSISSIPPI VALLEY TONIGHT. STRONG...DEEP
SURFACE LOW ASSOCIATED WITH THIS SYSTEM REMAINS WELL NORTH OF
GEORGIA BUT DRIVES A COLD FRONT INTO NORTHWEST GEORGIA EARLY
THURSDAY. MOISTURE IS VERY LIMITED CURRENTLY...BUT DEEPENING NATURE
OF THE SYSTEM PULLS SUFFICIENT MOISTURE NORTH AHEAD OF THE FRONT FOR
HIGH CHANCE TO LIKELY POPS ALONG AND JUST AHEAD OF THE FRONT
SWEEPING NORTHWEST TO SOUTHEAST ACROSS THE FORECAST AREA FROM LATE
TONIGHT THROUGH THURSDAY EVENING. RIGHT NOW ONLY THE NAM IS
GENERATING ENOUGH INSTABILITY FOR THUNDER...SO I WILL KEEP
THUNDERSTORMS LIMITED TO SLIGHT CHANCE. PRECIPITATION PUSHES
SOUTHEAST OUT OF THE FORECAST AREA THURSDAY NIGHT AS DRIER AIR
SWEEPS IN BEHIND THE FRONT. RIGHT NOW MODEL TRENDS ARE FOR CLEARING
SKIES THURSDAY NIGHT THROUGH FRIDAY...HOWEVER THE DEEP UPPER LOW
REMAINS ESSENTIALLY STATIONARY OVER THE SOUTHERN GREAT LAKES/WESTERN
OHIO VALLEY SO WE WILL NEED TO KEEP AN EYE ON TRENDS FOR POTENTIALLY
MORE CLOUD COVER ACROSS AT LEAST NORTH GEORGIA THROUGH THE PERIOD.
20
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO CHANGES FROM PREVIOUS LONG TERM. PREVIOUS LONG TERM DISCUSSION
FOLLOWS.
/ISSUED AT 336 AM EDT WED OCT 17 2012/
IN THE WAKE OF THE FRONTAL SYSTEM EXITING THE FORECAST AREA
THURSDAY NIGHT...THE UPPER LEVEL TROUGH AXIS OF A BROAD UPPER
CLOSED LOW CENTERED ACROSS THE GREAT LAKES SHOULD REMAIN WEST OF
THE AREA UNTIL THE SATURDAY NIGHT/EARLY SUNDAY TIME PERIOD.
GUIDANCE IS IN OVERALL AGREEMENT WITH THE MOISTURE FIELD STAYING
NORTH OF THE AREA WITH NO SIGNIFICANT SHORTWAVE INFLUENCE. THE
BEST CHANCE FOR ANY PRECIP WOULD BE FRIDAY NIGHT WITH A WEAK
SHORTWAVE IMPULSE ROTATING THROUGH GEORGIA. AT THIS POINT...IT
LOOKS LIKE IF ANY LOCATION HAD A CHANCE FOR PRECIP IT WOULD BE THE
NORTHERN PORTION OF THE AREA CLOSER TO THE HIGHER PROGGED LAYER RH
VALUES. HOWEVER...WITH THE ENERGY BEING A BIT TOO FAR SOUTH FROM
THE MOISTURE AND A SFC HIGH FILTERING IN FROM THE WEST...IT SHOULD
RESULT IN ONLY AN ENHANCEMENT IN CLOUD COVERAGE SO WILL KEEP A DRY
FORECAST. THE DRY AND PLEASANT WEATHER SHOULD PERSIST THROUGH THE
REMAINDER OF THE LONG TERM AS GUIDANCE IS IN GOOD CONSENSUS WITH A
1020-1022 MB SFC HIGH SETTING UP ACROSS THE CAROLINAS BY THE END
OF THE WEEKEND AND PERSISTING THROUGH TUESDAY. THIS SHOULD BRING
WEAK SOUTHEASTERLY TO SOUTHERLY FLOW ACROSS THE AREA.
FOR TEMPS...LATEST MEX GUIDANCE SEEMED SLIGHTLY COOL ON DAYTIME MAX
VALUES SO STAYED A BIT HIGHER. OTHERWISE...SHOULD SEE OVERNIGHT LOWS
MAINLY IN THE 40S HEADING INTO THE WEEKEND...THEN WARMING UP
GRADUALLY INTO THE UPPER 40S AND LOW 50S BY EARLY NEXT WEEK. HIGHS
WILL START OUT COOL IN THE UPPER 60S TO 70S AND GRADUALLY WARM INTO
THE LOW TO UPPER 70S BY SUNDAY.
BAKER
&&
.AVIATION...
06Z UPDATE...
SHRA AND TSRA AHEAD OF COLD FRONT WILL PUSH INTO NW GA 07-08Z...
BUT IS WEAKENING. REMOVED TSRA FROM NORTHERN TAFS...KEEPING -SHRA
INSTEAD. EXPECT AT LEAST A BRIEF PERIOD OF MVFR WITH THE SHRA BUT
LIFTING CIGS BEHIND THE RAIN AS THE LINE MOVES EAST. SE WINDS
AROUND 5KT OR SO TO START THE PERIOD...SHIFTING TO WEST AND
INCREASING AROUND 14Z ATL METRO AREA AND CSG...LATER FOR CSG AND
MCN. MAY SEE SOME LOW-END GUSTS THROUGH THE AFTERNOON. CLEARING
LATE TODAY AND TONIGHT.
//ATL CONFIDENCE...06Z UPDATE...
HIGH ON -SHRA. LOW ON POTENTIAL FOR -TSRA. MEDIUM ON TIMING.
HIGH ON MVFR CIGS...MEDIUM ON TIMING.
HIGH ON WINDS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 73 45 73 47 / 50 10 5 0
ATLANTA 73 49 72 48 / 60 5 0 0
BLAIRSVILLE 67 40 66 41 / 60 5 0 0
CARTERSVILLE 71 40 71 43 / 60 5 0 0
COLUMBUS 76 50 77 50 / 40 10 5 5
GAINESVILLE 72 47 70 47 / 50 5 0 0
MACON 77 46 76 46 / 50 10 5 5
ROME 71 40 73 43 / 50 5 0 0
PEACHTREE CITY 73 42 73 42 / 50 5 5 0
VIDALIA 81 60 80 54 / 40 20 10 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1129 PM CDT WED OCT 17 2012
.AVIATION...
A LARGE UPPER LOW PRESSURE SYSTEM WILL MOVE SHOWERS AND CIGS BACK
INTO THE REGION DURING THE DAY THURSDAY. UNTIL THEN...WEST WINDS
OF 12 TO 25 KTS WILL GUST THROUGH THE NIGHT...WITH OTHERWISE VFR
AND DRY CONDITIONS. ANY CIGS WILL BE 4500 FT OR HIGHER. SHOWERS
WILL SLIDE SOUTHEAST OVER THE REGION BY 15 TO 18Z...LASTING
THROUGH THURSDAY NIGHT. INITIALLY...THESE SHOULD BE VFR
SHOWERS...BUT BY LATE AFTERNOON AND EVENING...FREQUENT MVFR TO
POSSIBLE IFR CONDITIONS ARE NOW LIKELY...AT ALL SITES IN EASTERN
IOWA AND NORTHWEST ILLINOIS. WINDS WILL REMAIN AT OVERNIGHT LEVELS
THROUGH THE DAY THURSDAY. THE CONDITIONS LATE THURSDAY AFTERNOON
AND EVENING SHOULD GENERALLY RANGE FROM 800 FT TO 1500 FT CIGS AND
VISIBILITIES OF 4 TO 6 MILES IN LIGHT TO BRIEF MODERATE RAIN SHOWERS.
ERVIN
&&
.PREV DISCUSSION... /ISSUED 647 PM CDT WED OCT 17 2012/
UPDATE...
UPDATED POPS AND WEATHER TO REFLECT THE CURRENT RADAR POSITION OF
WIDESPREAD SHOWERS FOR THIS AFTERNOON AND EARLY EVENING.
ERVIN
SYNOPSIS...
12Z UA ANALYSIS HAS 850MB LOWS ON THE NORTH SHORE OF LAKE WINNIPEG
AND IN NORTHWEST MINNESOTA. AN 850MB COLD FRONT RAN FROM THE
MINNESOTA LOW INTO SOUTHEAST NEW MEXICO WITH A TROF FROM SOUTHERN
MINNESOTA INTO SOUTH TEXAS. SATELLITE/RADAR TRENDS SHOWS EXTENSIVE
LOW AND MID LEVEL CLOUDS WITH STRONG CONVECTION ACROSS MISSOURI
AND MORE SCATTERED CONVECTION ACROSS IOWA/ILLINOIS.
18Z SFC ANALYSIS HAS A LOW EAST OF KFAR WITH THE COLD FRONT SOUTH
INTO SOUTHEAST KANSAS. TWO MESO LOWS WERE IN SOUTHWEST MISSOURI
AND NORTHEAST OKLAHOMA. A PRE-FRONTAL TROF RAN FROM JUST EAST OF
KMSP TO ABOUT KIRK. DEW POINTS AHEAD OF THE COLD FRONT WERE IN THE
50S AND 60S WITH 20S AND 30S BEHIND THE COLD FRONT IN THE PLAINS.
SHORT TERM...TONIGHT AND THURSDAY
THE CURRENT PICTURE AT MID AFTERNOON HAS MID LEVEL FORCING OR A
WEAK VORT MAX PUSHING A SLUG OF MAINLY SHRA ACROSS THE CWFA. A
MUCH STRONGER VORT MAX IS ROTATING NORTHEAST ACROSS MISSOURI. IF
THE TRENDS OF THE RAP ARE CORRECT...THERE SHOULD BE A BAND OF
ENHANCED CONVECTION THAT DEVELOPS LATE THIS AFTERNOON IN THE
SOUTHEAST QUADRANT OF THE CWFA AND ROTATES NORTHEAST.
THIS BAND OF CONVECTION WILL BE ACROSS ROUGHLY THE EASTERN 40
PERCENT OF THE CWFA DURING THE EARLY EVENING HOURS BEFORE EXITING
THE CWFA. SOME LINGERING SHRA SHOULD THEN BE SEEN IN THE THE MID
AND LATE EVENING HOURS BEFORE ENDING.
AFTER MIDNIGHT THERE SHOULD BE SOME CLEARING OF THE CLOUDS WITH
DRY CONDITIONS AS CONDENSATION PRESSURE DEFICITS RISE
CONSIDERABLY. CONDENSATION PRESSURE DEFICITS IN THE 850-700MB
LAYER COLLAPSE AGAIN ACROSS THE CWFA PRIOR TO SUNRISE BUT THE
1000-850MB LAYER CONDENSATION PRESSURE DEFICITS ONLY LOWER
SLIGHTLY. THUS MOST OF THE AREA SHOULD REMAIN DRY AFTER MIDNIGHT
BUT SOME SPRINKLES MIGHT ENTER THE FAR NORTHWEST PART OF THE CWFA
JUST PRIOR TO DAWN.
THURSDAY...WRAP AROUND CLOUDS/PRECIP MOVE SOUTHEAST THROUGH THE
CWFA DURING THE MORNING HOURS. STEEP LAPSE RATES WILL AID IN
DEVELOPING NEW DIURNAL CLOUDS IN AREAS THAT WERE PARTIALLY CLEAR
AT SUNRISE. SCATTERED SHRA WILL BECOME MORE NUMEROUS DURING THE
DAY AS A VORT MAX ROTATES THROUGH AND INCREASES THE LIFT. THE
FREEZING LEVEL IS 3.0-3.5 KFT AGL PLUS/MINUS 700 FT DEPENDING ON
LOCAL ELEVATION ABOVE SEA LEVEL. HOWEVER...THE LOWEST 2 KFT ABOVE
THE GROUND REMAINS ABOVE FREEZING. THUS IN THE STRONGER SHOWERS
THE POTENTIAL DOES EXIST FOR SOME SMALL GRAUPEL TO DEVELOP THAT
REACHES THE GROUND.
TEMPERATURES WILL REMAIN IN THE 40S FOR MUCH OF THE DAY BUT THE
SOUTHEAST THIRD TO 40 PERCENT OF THE CWFA MAY MANAGE TO GET INTO
THE LOWER 50S. REGARDLESS...IT WILL BE A COLD RAW DAY WHEN THE
WIND IS FACTORED IN. 08
LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
UPPER LOW PROGGED TO EXIT INTO THE GREAT LAKES REGION BY FRI NGT.
UNTIL THEN WILL SEE CONSIDERABLE CLOUDINESS ALONG WITH BOUTS OF
LIGHT RAIN OR SHOWERS... AS SPOKES OF ENERGY ROTATE DOWN THE
BACKSIDE OF THE LOW. CLOUDS WILL ACT AS BLANKET AND LIMIT DIURNAL
SWINGS INTO FRI. CLOUD FORECAST CHALLENGING FRI NGT INTO SAT WITH
OVERALL INCOMING SUBSIDENCE IN WAKE OF DEPARTING LOW SUPPORTIVE OF
CLEARING... BUT NAM BUFR SOUNDINGS DEPICT A LOT OF LOW LEVEL
MOISTURE TRAPPED BENEATH SUBSIDENCE INVERSION. TIME OF YEAR WITH
LOWER SUN ANGLE BECOMING MORE FAVORABLE FOR THESE SCENARIOS AND
NUDGED TOWARD A MORE PESSIMISTIC SKY COVER FRI NGT THUS STAYING AT
OR ABOVE WARM SIDE OF GUIDANCE ON LOWS.
SAT-SUN... DRY WITH WARMING TREND TO ABOVE NORMAL TEMPS BY SUN AS
NEXT SIGNIFICANT TROUGH PUSHES INTO THE PACIFIC NORTHWEST... WHICH
RESULTS IN DOWNSTREAM AMPLIFICATION OF UPPER RIDGE OVER THE REGION.
MON-WED... ABOVE NORMAL TEMPS GENERALLY SUGGESTED WITH DEEP TROUGHING
OVER THE WESTERN CONUS AND SW FLOW ALOFT. SW FLOW COUPLED WITH FRONTAL
ZONE WAVERING NEARBY WILL RESULT IN OCCASIONAL RAIN CHCS AS WELL
DURING THE PERIOD. THE FIRST RAIN CHCS APPEAR TO ARRIVE AS EARLY AS
MONDAY MORNING WITH MORE ROBUST LOW LEVEL WARM ADVECTION REGIME.
OTHERWISE... IT IS DIFFICULT TO PIN DOWN RAIN CHCS THEREAFTER WITH
MODELS OFFERING DIFFERENCES ON LOCATION OF THE FRONT AND TIMING OF
UPPER LEVEL DISTURBANCES EJECTING FROM WESTERN TROUGH.
TRANSITION TO SIGNIFICANTLY COLDER REGIME IS DEPICTED BY ECMWF AND GFS
BY THE END OF NEXT WEEK INTO NEXT WEEKEND. 05
AVIATION... /ISSUED 1247 PM CDT WED OCT 17 2012/
A COLD FRONT WILL SWEEP THROUGH EASTERN IOWA AND ILLINOIS IN THE
18Z/17 TO 00Z/18 TIME FRAME. VFR WX IS GENERALLY EXPECTED WITH
SPRINKLES OR SHRA. ALONG/EAST OF THE MISSISSIPPI RIVER ISOLD TSRA
WILL BE POSSIBLE THAT ARE EXPECTED TO BECOME MORE NUMEROUS AFT
21Z. VFR CONDITIONS ARE EXPECTED BUT THERE MAY BE BRIEF INCURSIONS
OF MVFR CONDITIONS WITH ANY TSRA OR STRONGER SHRA. AFT 00Z/18 VFR
CONDITIONS ARE EXPECTED. CIGS WILL LOWER AGAIN AFT 12Z/18 BUT
SHOULD REMAIN VFR. 08
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 AM EDT THU OCT 18 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 432 PM EDT WED OCT 17 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF IN THE PROCESS OF
AMPLIFYING OVER THE PLAINS. THERE ARE A NUMBER OF EMBEDDED SHORTWAVES
IN THE DEEPENING TROF...BUT THE 130-140KT JET PER LATEST RUC
CURRENTLY DROPPING DOWN THE BACKSIDE OF THE TROF WILL BE THE FACTOR
LEADING TO THE TROF CONTINUING TO DEEPEN. IN FACT...TROF WILL BECOME
DEEP FOR THIS TIME OF YEAR. AT PEAK INTENSITY THU OVER THE
MID/UPPER MISSISSIPPI VALLEY...500MB HEIGHTS WILL BE 3.5 STANDARD
DEVIATIONS BLO THE LONG TERM AVG FOR MID OCT. AT THE SFC...LOW PRES
OF 29.1 INCHES IS OVER NW MN WITH COLD FRONT EXTENDING INTO FAR WRN
WI/FAR ERN IA AND MO. SO FAR...PCPN COVERAGE HAS BEEN GREATEST NEAR
THE SFC LOW OVER NW MN/ERN ND. HOWEVER...SHRA ARE INCREASING IN
COVERAGE SOUTHWARD ALONG/AHEAD OF COLD FRONT AS UPPER DIFFLUENCE
IMPROVES DUE TO AFOREMENTIONED UPPER JET DROPPING DOWN BACKSIDE OF
THE TROF.
AS TROF CONTINUES TO DEEPEN TONIGHT...A NEW LOW PRES CENTER IS
EXPECTED TO DEVELOP ON COLD FRONT IN ERN WI AND THEN LIFT NW TO THE
VCNTY OF WRN LAKE SUPERIOR THU MORNING. DEEPENING SYSTEM WILL LEAD
TO LOW-LEVEL JET RAMPING UP TO AROUND 50KT WHICH WILL TRANSPORT
ABUNDANT MOISTURE N INTO THE AREA (PRECIPITABLE WATER INCREASES TO
200PCT OF NORMAL OR BETTER). STRONG DIRECTIONAL DIFFLUENCE AT UPPER
LEVELS OVERTOP TIGHTENING LOW LEVEL FRONTAL BOUNDARY WILL SUPPORT AN
EXPANDING AREA OF SHRA SPREADING INTO THE FCST AREA TONIGHT. LIKELY
TO CATEGORICAL POPS LOOK ON TRACK. MODELS HAVE AND CONTINUE TO POINT
TOWARD SW/W UPPER MI RECEIVING THE HEAVIEST RAINFALL WITH THAT AREA
NEAR THE TRACK OF NW MOVING SFC WAVE. SO...AS IN PREVIOUS FCSTS...
HIGHEST POPS WERE PAINTED IN THAT AREA. NOT OUT OF THE QUESTION THAT
THERE MAY BE A FEW RUMBLES OF THUNDER GIVEN SHOWALTER INDEX FALLING
TOWARD ZERO. MIN TEMPS WILL BE WELL ABOVE NORMAL GIVEN CLOUDS/DEEP
MOISTURE. MINS SHOULD RANGE FROM THE MID 40S FAR W WHERE CAA WILL
GET UNDERWAY OVERNIGHT TO THE MID 50S EAST.
MAIN PUSH OF PCPN FROM TONIGHT WILL ROTATE NW OF THE AREA BY
MORNING. SO THERE MAY BE SOMEWHAT OF A BREAK IN PCPN FOR A WHILE THU
MORNING. HOWEVER...A SHORTWAVE ROTATING AROUND MIDLEVEL LOW WILL BE
SWINGING N TOWARD ERN UPPER MI...AND SHOULD BRING ANOTHER ROUND OF
GREATER SHRA COVERAGE INTO ESPECIALLY THE CNTRL AND ERN FCST AREA
FOR THE AFTN. TEMP RISE THU WILL BE LIMITED BY CLOUDS/CAA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT WED OCT 17 2012
AN UPPER LOW WILL BE SPINNING OVER FAR SW WI AT 00Z FRI...WITH A SFC
LOW TO THE N OF IT BUT S OF WRN LAKE SUPERIOR. A SHORTWAVE TROUGH
WILL BE JUST SE OF THE CWA AT 00Z FRI...MOVING E TO W TO NEAR THE
CENTER OF THE CWA BY 06Z FRI...THEN TO FAR WRN UPPER MI/FAR WRN LAKE
SUPERIOR BY 12Z FRI. MODELS ARE IN GOOD AGREEMENT WITH THE
SHORTWAVE...WITH ONLY MINOR TIMING DIFFERENCES BETWEEN THEM /THE GFS
WAS USED WITH THE HIGHEST WEIGHT SINCE THE TIMING WAS BETWEEN THE
FASTER NAM AND SLOWER ECMWF/. THE BEST CHANCES FOR WIDESPREAD PRECIP
WILL BE FROM 00Z-06Z FRI. AFTER 06Z FRI...THE SFC LOW MOVING THROUGH
WITH THE SHORTWAVE WILL QUICKLY MOVE TO SW WI. ALSO...BETWEEN
00Z-12Z FRI...THE MID/UPPER LOWS WILL BE STACKED JUST W OF LAKE
MICHIGAN...WITH LOW LEVEL CYCLONIC FLOW UP THE LONG AXIS OF LAKE
MICHIGAN. 850MB TEMPS WILL BE BETWEEN 0C AND -1C...SO LAKE ENHANCED
RAIN WILL BE POSSIBLE INTO SCENTRAL AND ERN UPPER MI LATE THU NIGHT
INTO FRI MORNING.
SFC FEATURES BEGIN TO BREAK DOWN QUICKLY ON FRI AS THE SYSTEM MOVES
TO SE LOWER MI BY LATE IN THE DAY. THE ECMWF IS ABOUT 12 HOURS
SLOWER IN MOVING THE SYSTEM INTO QUEBEC ON SAT. EVEN SO...MODELS
AGREE WITH SHOWING A SFC RIDGE MOVING INTO THE CWA AROUND 18Z
SAT...WITH AN UPPER RIDGE PUSHING IN FROM THE NW. THE RIDGE WILL
LEAD TO PRETTY QUIET WEATHER OVER THE WEEKEND...WITH ANY SIGNIFICANT
CHANCES FOR RAIN BEING OVER THE FAR E AS THE LOW MOVES E OF THE CWA
SAT...BUT THOSE CHANCES ARE SMALL. SINCE WARM AIR WILL NOT START TO
RETURN TO THE AREA UNTIL THE SFC RIDGE MOVES THROUGH...SAT WILL SEE
SIMILAR TEMPS TO FRI WITH HIGHS IN THE MID 40S TO MID 50S. SUN WILL
BE WARMER AS 850MB TEMPS INCREASE TO 8-10C...LEADING TO HIGHS IN THE
50S AND 60S.
AFTER SUN...SUBSTANTIAL MODEL DISAGREEMENT ON THE LOCATION OF A SFC
RIDGE THAT MAY MOVE IN THE REGION. THE PROBLEM COMES FROM A SFC
TROUGH/STATIONARY FRONT THAT WILL BE S OF THE RIDGE. THE GFS KEEPS
THE RIDGE OVER THE CWA THROUGH NEXT WED...KEEPING US DRY...BUT THE
ECMWF HAS THE TROUGH/FRONT OVER THE CWA THROUGH MUCH OF THE
PERIOD...WHICH WOULD RESULT IN A MOST WET FORECAST. WITH HIGH MODEL
DISAGREEMENT AND LOW RUN TO RUN CONTINUITY...USED A CONSENSUS OF
MODELS IN THIS PORTION OF THE FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 136 AM EDT THU OCT 18 2012
EXPECT IFR CONDITIONS TO PREDOMINANT THRU MOST OF THIS MRNG WITH
AREA OF RA/LLVL MSTR ASSOCIATED WITH DVLPG LO PRES NEAR MKX FCST TO
ENVELOP THE AREA AS THE LO MOVES NW THRU NRN WI. ALTHOUGH ANOTHER
DISTURBANCE MAY ROTATE INTO THE GRT LKS LATER TODAY AND BRING MORE
-SHRA...SOME LLVL DRYING ARND THE DEPARTING LO IN MN WL LIKELY CAUSE
AN IMPROVEMENT TO MVFR CONDITIONS. THE BEST CHC FOR MORE PERSISTENT
IFR CONDITIONS WL BE AT IWD...WHERE THE LLVL DRYING WL BE MORE
MINIMAL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT WED OCT 17 2012
A TRICKY FCST SHAPING UP TONIGHT INTO THU. DEEP SFC LOW NOW IN NW MN
WILL BE REPLACED BY A NEW LOW PRES WAVE THAT WILL DEVELOP IN ERN WI
TONIGHT AND THEN ROTATE NW TO VCNTY OF WRN LAKE SUPERIOR THU. IN
RESPONSE TO THE NEW LOW...A BRIEF PERIOD OF E TO SE GALES MAY
DEVELOP LATE TONIGHT INTO THU MORNING OVER CNTRL AND ERN LAKE
SUPERIOR. GIVEN UNCERTAINTY IN HOW QUICK OR DEEP THE NEW LOW WILL
BECOME BY THU MORNING...HELD OFF ON THE ISSUANCE OF A GALE WARNING
FOR NOW. AS A TROUGH MOVES THROUGH THURSDAY NIGHT...SOUTHEAST WINDS OVER
EASTERN LAKE SUPERIOR AND NORTHEAST WINDS OVER WESTERN LAKE SUPERIOR
WILL GUST TO AROUND 25KTS. WINDS WILL THEN DIMINISH TO BELOW 20KTS
FRIDAY THROUGH MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...KC
MARINE...ROLFSON/TITUS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
320 AM EDT THU OCT 18 2012
.SYNOPSIS...
A DEEP CLOSED LOW ALOFT IN THE UPPER MISSISSIPPI VALLEY WILL MOVE
SLOWLY EASTWARD ACROSS THE GREAT LAKES REGION...CONTINUING TO
INFLUENCE THE WEATHER PATTERN IN PENNSYLVANIA THROUGH THE FIRST
PART OF THE WEEKEND. A MATURE SURFACE CYCLONE WILL OCCLUDE OVER
THE UPPER MIDWEST AND BECOME VERTICALLY STACKED UNDER THE PARENT
UPPER LOW. A COLD FRONT WILL SURGE EASTWARD FROM THE OHIO VALLEY
AND CROSS THE APPALACHIANS EARLY TONIGHT. THE UPPER LEVEL SYSTEM
WILL LIFT AWAY FROM THE REGION ON SUNDAY...REPLACED BY HIGH
PRESSURE WHICH WILL DOMINATE THE WEATHER PATTERN INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
IR SATL LOOP SHOWS BAND OF MID CLOUDS LIFTING NEWD ACRS WRN PA IN
ASSOC WITH SFC WARM FRONT EXTENDING SEWD FROM SFC LOW OVR NRN WI.
SKIES ARE M/CLR OVR THE ERN HALF OF THE CWA...BUT RECENT TRENDS
SHOW VLY FOG AND AREA OF STRATUS EXPANDING IN MID-LWR SUSQ VLY.
5-10KT S-SE GRADIENT WINDS AND INC CLOUDS WILL KEEP STEADY TEMPS
NR 50F ACRS THE WRN MTNS...WHILE BLYR DECOUPLING ALLOWS TEMPS TO
DIP INTO THE LOW-MID 40S OVR ERN SXNS.
STRONG UPPER JET AND EMBEDDED SHORTWAVE TROF ROUNDING BASE OF DEEP
CLOSED LOW OVER THE UPPER MIDWEST WILL DRIVE A COLD FRONT EWD
THRU THE MID-UPPER OH VLY AND ACRS THE APPALACHIANS EARLY TONIGHT.
THE MAIN FCST CONCERNS IN THE NEAR TERM WILL BE TIMING OF FRONTAL
BAND RAINS AND POTENTIAL SVR WX ASSOC WITH LOW-TOPPED/CONVECTIVELY
ENHANCED LINE OF MOD SHOWERS/EMBEDDED TSTMS.
THE LATEST HRRR WEAKENS THE ONGOING CONVECTIVE FRONTAL BAND MOVG
EWD THRU THE LWR-MID OH/TN VLYS. MDL DATA INDICATES NEWD MSTR
RETURN AHEAD OF THE APPROACHING FRONTAL BAND WILL BE PINCHED-
OFF...RESULTING IN LIMITED INSTABILITY/CAPE OVER CENTRAL PA. THAT
SAID...MARGINAL DIURNAL HEATING COMBINED WITH STRONG UPPER LEVEL
DYNAMICS MAY BE SUFFICIENT TO SUPPORT AN INCREASE IN
CVRG/INTENSITY OF CONVECTIVE LINE ALONG/AHEAD OF THE COLD FRONT
AS IT MOVES INTO WRN PA THIS AFTN. SPC HAS MODIFIED THEIR SLIGHT
RISK AREA TO ONLY INCLUDE ONLY SW PA...THE LAUREL HIGHLANDS AND
S-CENTRAL MTNS. THEY ADMIT THAT THE SET-UP IS BORDERLINE FOR SLGT
RISK AND CONFIDENCE IS LOW.
WHILE THE MODELS ARE IN GENERAL AGREEMENT IN THEIR RESPECTIVE MASS
FIELDS...THERE ARE STILL SOME LINGERING QPF DIFFS ESP DURING THE
SECOND HALF OF THE PERIOD. INTENSITY OF SHOWERS SHOULD STRENGTHEN
THIS EVE AND EARLY TONIGHT AS THE FRONTAL BAND CROSSES THE CENTRAL
AND ERN PRTNS OF THE CWA. A WAVE SHOULD DEVELOP AND RIDE NWD ALONG
THE N-S FRONTAL ZONE...ENHANCING MSTR CONVERGENCE IN AN AXIS OF
ABV NORMAL PWATS EXTENDING NWD FROM THE WRN ATLC. DAY 1 AREAL QPF
AVGS BTWN 0.25-0.50" IN THE WEST AND 0.50-0.75" IN THE CENTRAL AND
ERN BASINS. WOULD NOT BE SURPRISE TO SEE SOME ISOLD 1 INCH PT
AMTS.
THE FCST BEST-TIMING FOR PCPN...GIVE OR TAKE...IS LATE AFTN/EARLY
EVE OVR WRN PA...MID EVE-EARLY TNT IN THE CENTRAL MTNS AND LATE
TNT THRU THE PREDAWN HOURS FRI ACRS THE ERN 1/3 OF THE CWA.
DRY SLOT WRAPPING AROUND THE VERTICALLY STACKED SYSTEM SHOULD
BRING AND END PCPN ACRS THE WRN MTNS BY LATE TNT...BUT THE FRONTAL
ZONE WILL SLOW ITS EWD PROGRESSION AS IT APPROACHES THE MID-ATLC
COAST DUE TO STRONG DOWNSTREAM UPPER RIDGE BUILDING OVR THE NRN
ATLC. THIS SHOULD KEEP FRONTAL RAINS GOING THRU THE END OF THE
PERIOD ACRS THE FAR ERN SXNS OF THE CWA.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
THE BACK EDGE OF THE N-S PCPN AXIS WILL SHIFT ENEWD INTO SRN NEW
ENGLAND EARLY FRIDAY. THE VERTICALLY STACKED LOW SHOULD REACH THE
LAKE ERIE VCNTY BY 12Z SAT. EXPECT SOME SHOWERS AHEAD OF THE UPPER
TROF AXIS MOVG THRU THE UPPER OH VLY...AS COOLER AIR ALOFT BEGINS
TO FILTER INTO THE AREA. THERE SHOULD BE A DRY PERIOD IN BETWEEN
THE DEPARTING FRONTAL BOUNDARY AND APPROACHING CLOSED H5 SYSTEM.
FCST TEMPS ARE ACTUALLY ABV NORMAL AS LLVL FLOW REMAINS FROM THE
SOUTH.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MASSIVE UPPER CYCLONE WILL CROSS THE REGION ONLY
SLOWLY...BRINGING THE COLDEST AIR OVERHEAD DURING THE DAY ON
SATURDAY. WE SHOULD SEE SCT/NRMS DAYTIME SHOWERS WITH THE COLD
AIR/INSTABILITY ON SATURDAY. COULD EVEN BE SOME THUNDER OR SMALL
HAIL...BUT JUST A TINY CHANCE OF THAT. WILL NOT MENTION YET.
A MASSIVE ANTICYCLONE THEN BUILDS OVER THE SOUTHEASTERN STATES AND
UP INTO THE MID-ATLANTIC. THE ROUND-ABOUT PATH FOR ANY MOISTURE
WILL MAKE IT TOUGH TO CREATE CLOUDS/PRECIP FOR THE REST OF THE
EXTENDED PERIOD. IN FACT...THE SW/WESTERLY FLOW WILL BE GRABBING
ABNORMALLY HOT AIR FROM THE PLAINS AND OHIO VALLEY AND HANDING IT
TO US. AT THE SAME TIME...THE FAST ZONAL WESTERLIES WILL BE SET
UP JUST TO OUR N. A SFC BOUNDARY WILL SET UP JUST TO OUR NORTH
PER THE ECMWF AND PERHAPS IN OUR NRN TIER PER GFS. THIS PATHWAY
WILL BE THE CAUSE FOR A LONG PERIOD OF SLIGHT CHCS IN THE NRN
TIER...WHILE THE REST OF THE AREA SHOULD BE DRY AND ABNORMALLY
WARM UNDER THE BIG HIGH PRESSURE. SHOULD THE BOUNDARY SET UP
FARTHER TO THE SOUTH...THE POPS WILL NEED TO CLIMB ACCORDINGLY...
BUT EVEN THEN...THE MOISTURE WILL HAVE TO TRAVEL A LONG WAY TO
GET HERE...AND QPFS WOULD BE LOW.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
LOOKING AT MAINLY VFR CONDITIONS OVERNIGHT.
SKIES WILL BE MAINLY CLEAR OVERNIGHT...WITH JUST SOME HIGH
CLDS TO THE WEST.
DESPITE THE LOW DEWPOINTS...SPOTS LIKE MDT AND LNS COULD SEE
A BIT OF FOG DURING THE HOURS SURROUNDING SUNRISE.
WHILE WIND FIELDS ARE NOT AS STRONG AS THEY WERE ON SUNDAY
NIGHT...STILL LOOKING AT SOME GUSTY WINDS TODAY...HAVE LLWS
AT BFD...JST...AND IPT. AT BFD AND JST...NEAR BEST LLJ...
WHILE IPT OFTEN GETS A GUSTY SE TO EAST WIND WITH WARM
ADVECTION AND FAIRLY STRONG WIND FIELDS.
SPC HAS THE AREA UNDER A SLIGHT RISK FOR STRONG TO SEVERE
STORMS LATER TODAY...AS THE COLD FRONT MOVES INTO THE AREA.
WILL CONTINUE TO LOOK THE SITUATION OVER.
MUCH OF FRIDAY INTO THE WEEKEND WILL LIKELY BE DRY AND VFR...
BUT MVFR CONDITIONS WITH A FEW SHOWERS WILL BE POSSIBLE...
MAINLY ACROSS THE HIGHER ELEVATIONS LIKE JST AND BFD...AS
THE UPPER LVL LOW MOVES ACROSS THE AREA.
OUTLOOK...
FRI...SHOWERS...MAINLY EARLY...THEN MAINLY VFR.
SAT...MVFR CIGS/SHRA POSS W...VFR ELSEWHERE.
SUN-MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DANGELO
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
322 AM CDT THU OCT 18 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
322 AM CDT THU OCT 18 2012
MAIN FORECAST CONCERNS REMAIN ON RAIN CHANCES TODAY THROUGH FRIDAY.
LATEST WATER VAPOR IMAGERY SHOWED A LARGE UPPER LEVEL LOW OVER THE
UPPER MISSISSIPPI RIVER VALLEY...CENTERED MAINLY OVER
NORTHWEST/WEST CENTRAL MINNESOTA. A POTENT TROUGH WAS PUSHING EAST
OUT OF THE MIDDLE MISSISSIPPI RIVER VALLEY INTO THE APPALACHIANS.
RADAR IMAGERY SHOWED A BAND OF SHOWERS ACROSS THE EASTERN HALF OF
WISCONSIN MOVING NORTHWEST IMPACTING LOCATIONS ACROSS CENTRAL INTO
NORTH CENTRAL WISCONSIN. A DRY SLOT WAS NOTED ACROSS EASTERN
IOWA/WESTERN WISCONSIN...INTO NORTH CENTRAL MINNESOTA. SHOWERS
WERE WRAPPING AROUND THE BACK SIDE OF THE LOW ACROSS EASTERN NORTH
DAKOTA/SOUTH DAKOTA. SCATTERED SHOWERS WERE DEVELOPING OVER
CENTRAL INTO SOUTHEAST MINNESOTA MOVING SOUTHEAST.
THE UPPER LOW WILL BE THE DOMINANT WEATHER FEATURE ACROSS THE REGION
TODAY AS IT DEEPENS AND SLIDES SOUTHEAST AND CENTERS OVER THE
FORECAST AREA. THE DRY SLOT WILL GRADUALLY BE OVERCOME TODAY AS THE
LOW WRAPS UP. LOOK FOR SHOWERS TO SLIDE BACK INTO THE FORECAST AREA
FROM THE NORTHWEST AND WEST TODAY AS THE LOW MOVES IN. RATHER LIGHT
PRECIPITATION AMOUNTS NOTED IN THE FORECAST MODELS TODAY THANKS TO
WEAK LIFT WITH THE LOW DIRECTLY OVERHEAD. LAPSE RATES STEEPEN
CONSIDERABLY THIS AFTERNOON...850-700MB LAPSE RATES AROUND 7 DEGREES
C/KM...SO WOULD EXPECT SCATTERED TO NUMEROUS RAIN SHOWERS TO DEVELOP
ACROSS THE FORECAST AREA. OTHERWISE...DRIZZLE OR LIGHT RAIN WILL BE
SEEN EARLY TODAY BEFORE THE STEEP LAPSE RATES MOVE IN DURING THE
AFTERNOON HOURS. WILL HAVE TO KEEP A CLOSE WATCH ON SURFACE BASED
CAPE THIS THIS AFTERNOON WITH THE OUTSIDE CHANCE OF A COLD AIR
FUNNEL. WOULDNT EXPECT TO SEE THEM TODAY WITH THE COOL SURFACE
TEMPS AND LACK OF APPRECIABLE CAPE. PLAN ON A COOL AND CLOUDY DAY
TODAY WITH HIGHS ONLY IN THE 40S.
THE CENTER OF THE LOW IS EXPECTED TO DRIFT SOUTH TONIGHT OVER
NORTHERN ILLINOIS...BUT GIVEN THE EXPANSIVE AREA OF THE
LOW ENCOMPASSING MUCH OF THE GREAT LAKES REGION INTO THE MID
MISSISSIPPI RIVER VALLEY...IT WILL CONTINUE TO CONTROL THE WEATHER
ACROSS THE AREA. THE CONVECTIVE SHOWERS SHOULD TAPER OFF AROUND
SUNRISE. FORECAST SOUNDINGS CONTINUE TO SHOW A NEARLY SATURATED
LAYER FROM THE SURFACE THROUGH AROUND 800 MB SO CANNOT RULE OUT
SOME DRIZZLE OVERNIGHT. HAVE DECREASED MEASURABLE PRECIPITATION
CHANCES OVER THE PREVIOUS FORECAST. PLAN ON SOME AREAS OF DRIZZLE
TONIGHT WITH THE POSSIBILITY OF ISOLATED SHOWERS. OTHERWISE...PLAN
ON CLOUDY SKIES OVERNIGHT WITH LOW TEMPERATURES FALLING INTO THE
UPPER 30S TO LOWER 40S.
A POTENT SHORTWAVE ROTATING AROUND THE NORTH SIDE OF THE LOW IS
EXPECTED TO PUSH INTO NORTHWESTERN SECTIONS OF THE FORECAST AREA
FRIDAY MORNING THEN PROGRESS SOUTHEAST THROUGH THE MORNING
HOURS...GENERATING SHOWERS AS IT MOVES THROUGH. THE WAVE WILL
QUICKLY EXIT THE AREA FRIDAY AFTERNOON MOVING INTO SOUTHEAST
IOWA/NORTHERN ILLINOIS BY LATE AFTERNOON. ANY LINGERING RAIN SHOWERS
WILL END LATE FRIDAY AFTERNOON. CLOUD COVER WILL BE A BIT OF A
CHALLENGE FRIDAY NIGHT INTO SATURDAY MORNING WITH LINGERING LOW
LEVEL MOISTURE AND CYCLONIC FLOW ALOFT. UPPER LEVEL RIDGING WILL BE
BUILDING IN ACROSS MINNESOTA LATE FRIDAY NIGHT THEN SLIDING INTO
WESTERN WISCONSIN SATURDAY MORNING AS THE UPPER LOW EXITS TO THE
EASTERN GREAT LAKES. IF THE CLOUDS CAN CLEAR AREAS OF FOG MAY
DEVELOP LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING. PLAN ON LOW
TEMPERATURES FALLING INTO THE 30S. CLOUDS ARE EXPECTED TO DECREASE
ACROSS THE AREA SATURDAY MORNING INTO SATURDAY AFTERNOON AS THE
RIDGE MOVES OVER THE UPPER MISSISSIPPI RIVER VALLEY. PLAN ON MOSTLY
SUNNY SKIES BY SATURDAY AFTERNOON. HIGHS ON SATURDAY WILL RANGE FROM
THE LOWER 50S ACROSS NORTHERN WISCONSIN TO THE UPPER 50S OVER
NORTHEAST IOWA. 925 MB TEMPERATURES WARM SATURDAY NIGHT INTO SUNDAY
MORNING...FROM AROUND 9C AT 00Z SUN TO AROUND 12 C BY 12Z. THIS WILL
SET THE STAGE FOR RATHER PLEASANT DAY ON SUNDAY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
322 AM CDT THU OCT 18 2012
18.00 MEDIUM RANGE MODELS SHOW A PLEASANT DAY ON TAP FOR SUNDAY WITH
MOSTLY SUNNY SKIES AND HIGHS CLIMBING INTO THE 60S. AN ACTIVE
PATTERN WILL THEN TAKE HOLD ON THE REGION SUNDAY NIGHT THROUGH THE
MIDDLE OF NEXT WEEK AS A BAROCLINIC ZONE SETS UP ACROSS THE REGION
AND FLOW ALOFT TURNS SOUTHWEST AS A TROUGH DEVELOPS OVER THE WESTERN
CONUS. THE EXACT LOCATION OF THE BAROCLINIC ZONE IS DIFFICULT TO PIN
POINT AT THIS TIME BUT CURRENT THINKING IS THAT IT WILL STRETCH FROM
THE CENTRAL PLAINS...NEBRASKA/KANSAS...NORTHEAST INTO THE UPPER
MISSISSIPPI RIVER VALLEY. SHORTWAVES MOVING THROUGH THE SOUTHWEST
FLOW ALOFT WILL INTERACT WITH THIS BOUNDARY PRODUCING PERIODIC SHOWER
AND THUNDERSTORM CHANCES. FORECAST MODELS ARE IN REASONABLE AGREEMENT
SUNDAY NIGHT INTO MONDAY. THE FIRST WAVE IS EXPECTED TO MOVE ACROSS
THE CENTRAL PLAINS AND INTO THE FORECAST AREA SUNDAY NIGHT WITH THE
BOUNDARY LIFTING NORTH INTO SOUTHERN MINNESOTA/SOUTHERN WISCONSIN.
THE ECMWF IS SHOWING 0-3KM MUCAPE VALUES INCREASING TO AROUND
1300J/KG ACROSS LOCATIONS WEST OF THE MISSISSIPPI RIVER WITH 0-6 KM
BULK SHEAR VALUES AROUND 30 KTS. DECIDED TO GO WITH SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF SOUTHEAST MINNESOTA...NORTHEAST
IOWA...AND FAR SOUTHWEST WISCONSIN. THINKING WEST CENTRAL INTO
CENTRAL WISCONSIN WOULD SEE ISOLATED THUNDERSTORMS WITH THE HIGHEST
INSTABILITY OFF TO THE SOUTHWEST. THE FRONT IS EXPECTED TO LIFT NORTH
INTO NORTHERN WISCONSIN MONDAY NIGHT. ANOTHER WAVE LOOKS TO MOVE
THROUGH DURING THE DAY ON TUESDAY...DRAGGING A COLD FRONT ACROSS THE
FORECAST AREA. COULD SEE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
AS THE FRONT MOVES THROUGH. DEPENDING ON THE INSTABILITY AND HOW FAR
NORTH THE WARM FRONT GETS MONDAY NIGHT...THERE IS THE OUTSIDE CHANCE
THAT THE STORMS COULD BE STRONG TO SEVERE WITH 0-6KM BULK SHEAR OF
40 TO 50 KTS AND 0-3KM MUCAPE VALUES AROUND 1500 J/KG. THE COLD
FRONT IS EXPECTED TO SLIDE SOUTHEAST INTO NORTHERN ILLINOIS/SOUTHERN
IOWA TUESDAY NIGHT INTO WEDNESDAY TAKING THE INSTABILITY BACK TO THE
SOUTH. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO
WEDNESDAY AS SOUTHWEST FLOW ALOFT CONTINUES.
&&
.AVIATION...THROUGH 06Z FRIDAY
1138 PM CDT WED OCT 17 2012
AREA OF SURFACE LOW PRESSURE REMAINING NEARLY STATIONARY THIS
EVENING NORTH OF KGFK. COLD FRONT EXTENDS SOUTHEAST FROM THE LOW
INTO SOUTHEAST WISCONSIN. PLENTY OF MOISTURE REMAINS IN PLACE
BEHIND THE FRONT AND WITH THE CYCLONIC FLOW AND PERSISTENT WEAK
ISENTROPIC UP GLIDE ON THE 295K SURFACE...AN EXPANSIVE CLOUD DECK
IS IN PLACE. CEILINGS ARE SLOWLY LOWERING AND EXPECT BOTH TAF
SITES TO BE AT OR NEAR MVFR BY ISSUANCE TIME. OBSERVATIONS ACROSS
CENTRAL AND WESTERN MINNESOTA INDICATE THE HEIGHTS SHOULD CONTINUE
TO LOWER BUT REMAIN MVFR THROUGH THE NIGHT. SOME IFR CONDITIONS
HAVE PERSISTED OVER NORTHERN MINNESOTA...GENERALLY ALONG AND NORTH
OF THE FRONT. THESE WILL HAVE TO BE MONITORED AS THERE IS THE
POTENTIAL FOR THEM TO PUSH INTO KRST AS THE SURFACE LOW WEAKENS
AND BEGINS TO MOVE SOUTHEAST. SOME LIGHT RAIN SEEN ON RADAR OVER
THE EASTERN DAKOTAS HAS MADE LITTLE EASTWARD PROGRESS BUT THE
18.01Z HRRR AND 18.00Z NAM SUGGEST SOME OF THIS COULD GET INTO THE
REGION LATE TONIGHT SO WILL SHOW VCSH FOR BOTH TAF SITES. BETTER
CHANCE OF SOME PERSISTENT LIGHT RAIN STARTING THURSDAY MORNING AND
CONTINUING THROUGH THE AFTERNOON AS THE NAM SHOWS A SHORT WAVE
TROUGH ROTATING AROUND THE UPPER LEVEL LOW TO PROVIDE A LITTLE
EXTRA FORCING TO THE ISENTROPIC UP GLIDE AND WILL CARRY PREVAILING
LIGHT RAIN WITHOUT A VISIBILITY RESTRICTION. SHOULD SEE THE WINDS
SWING AROUND TO THE NORTHWEST AT KRST WHILE GOING LIGHT AT KLSE
LATE THURSDAY AFTERNOON AS THE REMAINS OF THE SURFACE LOW MOVES
THROUGH THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
322 AM CDT THU OCT 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1138 PM CDT WED OCT 17 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
217 PM CDT WED OCT 17 2012
FORECAST CONCERNS THROUGH THE SHORT TERM INCLUDE RAIN CHANCES AND
TEMPERATURES.
WATER VAPOR SATELLITE LOOP SHOWING DEEPENING MID-LEVEL LOW/TROUGH
OVER THE EASTERN DAKOTAS EXTENDING SOUTHWARD INTO EASTERN NEBRASKA
AND KANSAS. AT THE SURFACE...LOW PRESSURE WAS SITUATED OVER NORTHERN
MN WITH A COLD FRONT EXTENDING SOUTHWARD ALONG THE MISSISSIPPI RIVER
AND THEN ACROSS EASTERN IA/CENTRAL MO. RADAR MOSAIC SHOWING
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS EASTERN IA INTO
CENTRAL WI IN LIFT AHEAD OF THE ADVANCING COLD FRONT.
LATEST NCEP MODELS/ECMWF/GEM ALL IN PRETTY GOOD AGREEMENT WITH
HANDLING OF DEEP/CLOSED LOW THROUGH THE PERIOD.
JET ENERGY COMING OUT OF THE BASE OF THE TROUGH OVER THE CENTRAL
PLAINS WILL RACE NORTHEAST WITH A 100KT 300MB JETLET OVER WESTERN WI
BY 03Z PER THE NAM. DIRECT CIRCULATION ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF THIS JET ACTS TO ENHANCE 850-500MB FRONTOGENETIC
CIRCULATION ACROSS CENTRAL/EASTERN WI. THIS SHOULD IN TURN ACT TO
ENHANCE BAND OF SHOWERS/ISOLATED THUNDERSTORMS. BELIEVE AREAS EAST
OF A MAUSTON TO BOSCOBEL WILL SEE MOST OF THIS ACTIVITY. AFTER
MIDNIGHT THIS FORCING GETS DISPLACED NORTHEAST...PUSHING MOST OF THE
SHOWERS OUT OF THE AREA AS DRY SLOT OF THE DEEP LOW OVERTAKES THE
AREA. KEPT SHOWER CHANCES NORTHEAST OF I-94 IN THE 06-12Z TIME
FRAME. TOWARD MORNING...THETA-E TROWAL WRAPPING AROUND THE CLOSED
LOW EXPECTED TO SPREAD SHOWERS SOUTHEASTWARD ACROSS THE
DAKOTAS/SOUTHERN MN. EASTERN NOSE OF THESE SHOWERS MAY MAKE IT INTO
OUR FAR WESTERN FORECAST AREA. WILL GO WITH A 20-30 POP TO COVER
THIS. OTHERWISE...LOOK FOR OVERNIGHT LOWS BOTTOMING OUT IN THE
40S.
FOR THURSDAY THROUGH FRIDAY...THE CLOSED LOW WILL REMAIN ANCHORED
OVER WI FOR COOLER/BELOW NORMAL TEMPERATURES ALONG WITH SCATTERED
SHOWERS. LOOK FOR ONLY AROUND A 5 DEGREE DIURNAL RISE MOST LOCATIONS
ON THURSDAY WITH HIGHS IN THE 40S. LOWS THURSDAY NIGHT EXPECTED TO
DIP TO AROUND 40 WITH FRIDAY REMAINING AROUND 10 DEGREES BELOW NORMAL
AS HIGHS TOP OF AROUND 50.
FOR FRIDAY NIGHT THROUGH SATURDAY...THE CLOSED LOW MOVES INTO THE
EASTERN GREAT LAKES WITH A RIDGE OF HIGH PRESSURE BUILDING IN FROM
THE PLAINS. SKY TRENDS COULD BE A BIT TRICKY THROUGH THIS PERIOD AS
THE NAM LOW-LEVEL RH FIELD/BUFKIT SOUNDING HINTING AT STRATUS
GETTING TRAPPED UNDER THE SUBSIDENCE INVERSION. CLIMATOLOGICALLY...
WITH THE LOWER SUN ANGLE/LESS MIXING...THIS SEEMS TO MAKE SENSE.
DESPITE THE RIDGE BUILDING IN...WILL DELAY CLEARING UNTIL LATER
SATURDAY AFTERNOON AS THE BACK SIDE OF THE RIDGE AXIS PRODUCES
SOUTHERLY FLOW TO MIX OUT THE STRATUS. THIS WILL ALSO HAVE AN IMPACT
ON TEMPERATURES AS WELL...ESPECIALLY HIGHS ON SATURDAY. BASED ON
CLOUD TREND...WILL KEEP HIGHS IN THE 50S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
217 PM CDT WED OCT 17 2012
LATEST GFS AND ECMWF SHOWING MID/UPPER LEVEL RIDGE MOVING EAST
ACROSS THE AREA SATURDAY NIGHT/SUNDAY. THIS ALLOWS A COLD FRONT TO
MOVE FROM THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER
REGION BY SUNDAY AFTERNOON. SOUTHERLY FLOW/WARM AIR ADVECTION AHEAD
OF THE COLD FRONT EXPECTED TO PUSH TEMPERATURES INTO THE 60S FOR
HIGHS ON SUNDAY UNDER MOSTLY SUNNY SKIES. MODELS THEN START TO
DIVERGE A BIT WITH PLACEMENT OF THE COLD FRONTAL BOUNDARY SUNDAY
NIGHT THROUGH WEDNESDAY WITH SOUTHWEST FLOW ALOFT. GFS PUSHES THE
FRONT FARTHER SOUTH OF THE AREA THEN THE ECMWF. BOTH MODELS SHOWING
A COUPLE WAVES OF LOW PRESSURE MOVING UP ALONG THIS FRONTAL BOUNDARY
FOR SHOWER/THUNDER CHANCES. BEST CHANCE FOR THUNDER APPEARS TO BE
MONDAY INTO MONDAY NIGHT. OTHERWISE...LOOKS LIKE TEMPERATURES SHOULD
REMAIN A FEW DEGREES ABOVE NORMAL WITH HIGHS MAINLY IN THE 60S AND
OVERNIGHT LOWS MAINLY IN THE 40S.
&&
.AVIATION...THROUGH 06Z FRIDAY
1138 PM CDT WED OCT 17 2012
AREA OF SURFACE LOW PRESSURE REMAINING NEARLY STATIONARY THIS
EVENING NORTH OF KGFK. COLD FRONT EXTENDS SOUTHEAST FROM THE LOW
INTO SOUTHEAST WISCONSIN. PLENTY OF MOISTURE REMAINS IN PLACE
BEHIND THE FRONT AND WITH THE CYCLONIC FLOW AND PERSISTENT WEAK
ISENTROPIC UP GLIDE ON THE 295K SURFACE...AN EXPANSIVE CLOUD DECK
IS IN PLACE. CEILINGS ARE SLOWLY LOWERING AND EXPECT BOTH TAF
SITES TO BE AT OR NEAR MVFR BY ISSUANCE TIME. OBSERVATIONS ACROSS
CENTRAL AND WESTERN MINNESOTA INDICATE THE HEIGHTS SHOULD CONTINUE
TO LOWER BUT REMAIN MVFR THROUGH THE NIGHT. SOME IFR CONDITIONS
HAVE PERSISTED OVER NORTHERN MINNESOTA...GENERALLY ALONG AND NORTH
OF THE FRONT. THESE WILL HAVE TO BE MONITORED AS THERE IS THE
POTENTIAL FOR THEM TO PUSH INTO KRST AS THE SURFACE LOW WEAKENS
AND BEGINS TO MOVE SOUTHEAST. SOME LIGHT RAIN SEEN ON RADAR OVER
THE EASTERN DAKOTAS HAS MADE LITTLE EASTWARD PROGRESS BUT THE
18.01Z HRRR AND 18.00Z NAM SUGGEST SOME OF THIS COULD GET INTO THE
REGION LATE TONIGHT SO WILL SHOW VCSH FOR BOTH TAF SITES. BETTER
CHANCE OF SOME PERSISTENT LIGHT RAIN STARTING THURSDAY MORNING AND
CONTINUING THROUGH THE AFTERNOON AS THE NAM SHOWS A SHORT WAVE
TROUGH ROTATING AROUND THE UPPER LEVEL LOW TO PROVIDE A LITTLE
EXTRA FORCING TO THE ISENTROPIC UP GLIDE AND WILL CARRY PREVAILING
LIGHT RAIN WITHOUT A VISIBILITY RESTRICTION. SHOULD SEE THE WINDS
SWING AROUND TO THE NORTHWEST AT KRST WHILE GOING LIGHT AT KLSE
LATE THURSDAY AFTERNOON AS THE REMAINS OF THE SURFACE LOW MOVES
THROUGH THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
217 PM CDT WED OCT 17 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER CO
929 AM MDT THU OCT 18 2012
.UPDATE...NO CHANGES PLANNED AT THIS TIME BUT WILL NEED TO KEEP AN
EYE ON ZONES ADJACENT TO THE HIGH WIND WARNING TO SEE IF THEY NEED
TO BE ADDED...MAINLY CONCERNED WITH ZONES 38 AND 44. LONGMONT
ANTICYCLONE STILL CONTINUING IN THE DENVER AREA BUT SHOULD BREAK
DOWN LATER THIS MORNING AS STRONGER NORTHWESTERLY WINDS MIX DOWN
TO THE SURFACE.
&&
.AVIATION...NO CHANGES AT THIS TIME. LONGMONT ANTICYCLONE STILL
OCCURRING IN THE DENVER AREA BUT SHOULD BREAK DOWN LATE
MORNING/EARLY AFTN AS STRONGER NORTHWEST WINDS MIX DOWN TO THE
SURFACE. WILL KEEP TIMING OF THE CURRENT TAF REGARDING ANY WIND
SHIFTS AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 322 AM MDT THU OCT 18 2012/
SHORT TERM...STG NWLY FLOW ALOFT WIL CONTINUE OVER THE AREA TODAY
WITH A VERY DRY AIRMASS IN PLACE. BIGGEST CONCERN FROM LATE MORNING
THRU THE MID AFTN HOURS WILL BE HIGH WND POTENTIAL OVER THE FAR NERN
PLAINS. 50-60 KT FLOW IN THE 800-700 MB LAYER COULD MIX DOWN TO THE
SFC AND PRODUCE SOME WIND GUSTS TO 60 MPH MAINLY EAST OF NEW RAYMER TO
AKRON LINE FM 15Z-21Z. MEANWHILE WITH GUSTY WINDS AND LOW HUMIDITY
LEVELS BY EARLY AFTN WILL CONTINUE WITH RED FLAG WARNING AND
EXPAND IT A BIT FURTHER WEST AND SOUTH AS WELL OVER NERN CO. HIGHS
THIS AFTN LOOK SIMILAR TO WED AS 850-700 MM TEMPS DO NOT CHANGE
MUCH.
FOR TONIGHT WINDS WILL REMAIN GUSTY OVER THE FAR NERN PLAINS THROUGH
THE EARLY EVENING HOURS HOWEVER SPEEDS SHOULD BE BELOW WARNING
CRITERIA.
LONG TERM...UPPER RIDGING IS PROGGED ACROSS COLORADO FRIDAY INTO
SATURDAY WITH WEAKER NORTHWESTERLY FLOW ALOFT. ON SATURDAY...THE
FLOW ALOFT IS ZONAL...THEN SOUTHWESTERLY BY LATE SATURDAY NIGHT.
THE SYNOPTIC SCALE ENERGY IS BENIGN FRIDAY THROUGH SATURDAY NIGHT.
THE LOW LEVEL PRESSURE AND WIND FIELDS SHOW WEAK TROUGHING EAST OF
THE MOUNTAINS ALL FOUR PERIODS. NORMAL DIURNAL PATTERNS MAY WIN
OUT BUT THERE COULD BE SOME DOWNSLOPING AT TIMES. WINDS WILL
DEFINITELY BE LESS SIGNIFICANT AS THEY THEY HAVE BEEN LATELY.
MOISTURE-WISE...THERE IS SOME NOW AND AGAIN PROGGED IN THE UPPER
LEVELS ALL FOUR PERIODS...BUT THE LOWER AND MID LEVELS ARE QUITE
DRY. `PRECIPITABLE WATER VALUES ARE IN THE 0.20 TO 0.35 INCH RANGE
ALL FOUR PERIODS. THERE IS NO MEASURABLE PRECIPITATION PROGGED ON
THE QPF FIELDS FRIDAY THROUGH SATURDAY NIGHT. NO POPS. WINDS
SHOULD NOT BE AN ISSUE. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 4-8 C
WARMER THAN TODAY`S. SATURDAY`S WARM-UP ANOTHER 1-3 C OVER
FRIDAY`S. MOS GUIDANCE VALUES ARE INFLATED AGAIN. FOR THE LATER
DAYS...SUNDAY THROUGH WEDNESDAY...MODELS BASICALLY HAVE ZONAL FLOW
ALOFT ON SUNDAY...THEN SOUTHWESTERLY LATE SUNDAY NIGHT THROUGH
WEDNESDAY. THE GFS HAS A WEAK UPPER TROUGH TO MOVE ACROSS SUNDAY
AFTERNOON...THE ECMWF DOES NOT. WIND SPEEDS ALOFT ARE MODERATE ON
SUNDAY THROUGH MONDAY NIGHT...THEN THEY INCREASE. BY WEDNESDAY...
SPEEDS OVER THE CWA ARE AROUND 100 KNOTS AT JET LEVEL...WITH A JET
MAX MOVING INTO NORTHWEST COLORADO BY WEDNESDAY EVENING ACCORDING TO
THE GFS. ON WEDNESDAY...THE GFS HAS A BROAD MEAN TROUGH DEEPENING
OVER THE WESTERN UNITED STATES. THE ECMWF SHOWS A MORE FLAT
TROUGH. MOISTURE IS POOR...BUT INCREASES A BIT LATER ON WEDNESDAY.
TEMPERATURES ARE ABOVE NORMALS.
AVIATION...WITH NWLY FLOW COMING OFF THE CHEYENNE RIDGE CURRENTLY
HAVE AN LONGMONT ANTICYCLONE IN PLACE NEAR DENVER. THE HRRR AND TO
SOME EXTENT THE RAP HAVE THIS FEATURE CENTERED OVER SWRN WELD COUNTY
BY MIDDAY. AS A RESULT WINDS EARLY THIS MORNING HAVE BEEN SELY
WHICH SHOULD SHIFT TO MORE SLY BY 12Z. BY 18Z WINDS SHOULD BECOME
MORE NNWLY WITH INCREASING SPEEDS BY EARLY AFTN. SOME GUSTS IN THE
25-30 KT RANGE WILL BE POSSIBLE THRU LATE AFTN. WINDS SHOULD
GRADUALLY DECREASE BY 00Z AND THEN BECOME MORE WSW AFTER SUNSET AND
THEN SSW BY 06Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ042-048>051.
RED FLAG WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ238-241>251.
&&
$$
SHORT TERM...COOPER/RPK
LONG TERM....RJK
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS MIAMI FL
1000 AM EDT THU OCT 18 2012
.UPDATE...
UPDATED THE SHORT TERM FORECAST TO INCREASE THE POPS ACROSS THE
REGION. THE 12Z SOUNDING AND OTHER REGIONAL PWAT REPORTS INDICATE
AN INCREASING TREND IN MOISTURE ACROSS THE REGION WITH REGIONAL
PWATS NEAR 2 INCHES. IN ADDITION THE RECENT GUIDANCE AND RECENT
WATER VAPOR IMAGERY CONTINUE TO INDICATE A MID TO UPPER LEVEL
SHORT WAVE ENTERING THE EASTERN GULF AND FLORIDA STRAITS. AND EARLIER
THIS MORNING THERE WAS CONSIDERABLE CONVECTION IN THE VICINITY OF
THE CENTRAL FLORIDA KEYS. GIVEN ALL THESE FACTORS...THERE COULD BE
ISOLATED AREAS OF HEAVY RAINFALL ALTHOUGH THUNDERSTORM ACTIVITY IS
EXPECTED TO BE ISOLATED. THE CONVECTION IS MAINLY EXPECTED TO
INCREASE DURING THE EARLY AFTERNOON THROUGH THE EVENING HOURS.
60
&&
.PREV DISCUSSION... /ISSUED 724 AM EDT THU OCT 18 2012/
AVIATION...PLENTY OF LINGERING LOW-LEVEL MOISTURE AND CLOUD
COVERAGE WITH BASES RANGING FROM 6-10 KFT WILL REMAIN IN PLACE THIS
MORNING. SOME OF THE INTERIOR AREAS MAY EVEN EXPERIENCE BRIEF
PERIODS WITH REDUCED VISIBILITIES IF ANY OF THIS CLOUD COVERAGE
CLEARS...WITH THE BEST CHANCE INLAND AWAY FROM THE IMMEDIATE COAST.
AS THE DAY PROGRESSES...PLENTY OF LOW-LEVEL MOISTURE UP TO 10-13 KFT
COMBINED WITH WHAT IS LEFT OF AN OLD FRONTAL BOUNDARY WILL KEEP THE
RAIN CHANCES IN THE FORECAST TODAY. THE LATEST WRF AND HRRR MODEL
REFLECTIVITIES INDICATE MAINLY SCATTERED SHOWERS REMAINING POSSIBLE
ONCE AGAIN THROUGH THE LATE MORNING AND AFTERNOON PERIODS. WESTERLY
DEEP LAYER STEERING FLOW WILL FAVOR THE BEST SHOWER COVERAGE ACROSS
THE INTERIOR AND EASTERN HALF OF THE PENINSULA...SIMILAR TO
YESTERDAY.
PREV DISCUSSION... /ISSUED 244 AM EDT THU OCT 18 2012/
DISCUSSION...LARGE SCALE MID LEVEL TROUGH IS CURRENTLY CENTERED
OVER THE UPPER MISSISSIPPI VALLEY. A SHORT WAVE TROUGH EMBEDDED IN
THIS FLOW MOVED ACROSS SOUTH FLORIDA WEDNESDAY AFTERNOON
GENERATING SOME HEAVY THUNDERSTORMS ACROSS THE NORTHEAST PORTION
OF THE REGION WITH ISOLATED LOCATIONS RECEIVING OVER FOUR INCHES
OF RAINFALL. THIS TROUGH HAS LIFTED TO THE NORTHEAST WHILE AT THE
SURFACE, A WEAK BOUNDARY IS LOCATED JUST OFF THE SOUTHEAST COAST.
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE BEING GENERATED
ALONG THE BOUNDARY. ANOTHER WEAKER SHORT WAVE TROUGH IS LOCATED
OVER THE CENTRAL GULF OF MEXICO WHICH IS SOMEWHAT EVIDENT ON WATER
VAPOR IMAGERY. THE GFS, NAM AND ECMWF ALL DEPICT THIS FEATURE BUT
THE NAM HAS A MORE PRONOUNCED TROUGH AND THUS YIELDS THE HIGHEST
POPS. MUCH DRIER AIR ABOVE 10-15K FEET IS CURRENTLY MOVING INTO
THE REGION BEHIND THE EXITING TROUGH. WHILE THERE WILL BE SOME
INCREASE IN MOISTURE WITH THE SECONDARY TROUGH, IT WOULD APPEAR
THE NAM IS SUFFERING ONCE AGAIN FROM MESOSCALE BIAS. THE TROUGH
AXIS WILL CONTINUE THE SOUTHWEST STEERING FLOW ACROSS SOUTH
FLORIDA SO ANYTHING THAT DEVELOPS OVER THE INTERIOR WILL MOVE
AGAIN TOWARDS THE EAST COAST METRO AREA. THE RAPID REFRESH WHICH
PERFORMED VERY WELL WITH YESTERDAY`S CONVECTION AND ITS CURRENT
RUN GOES OUT THROUGH 18Z, SHOWS SOME DEVELOPMENT BEGINNING AROUND
17Z BUT DOES NOT GET TOO AGGRESSIVE. SO THAT BEING SAID HAVE LEANED
CLOSER TO THE MAV NUMBERS WHICH IS QUITE A BIT LESS FROM THE MET
GUIDANCE. ALL MODEL GUIDANCE NOW SHOWS THE MAIN TROUGH LIFTING TO
THE NORTHEAST THROUGH SATURDAY AS A STRONG TROUGH DEVELOPS IN THE
NORTH PACIFIC. THIS WILL ALLOW FOR THE DRIER AIR MASS TO FILTER
DOWN ACROSS THE PENINSULA ON SATURDAY INTO EARLY NEXT WEEK WITH
DEW POINTS ALSO DROPPING INTO THE 60S. SO A COUPLE MORE DAYS OF
THE HIGHER HUMIDITY AND MORE PLEASANT CONDITIONS FOR THE WEEKEND
AND AT LEAST EARLY NEXT WEEK.
MARINE...TRANQUIL WIND AND SEAS ARE EXPECTED THROUGH THE
REMAINDER OF THIS WEEK AND THEN ONLY A SLOW INCREASE IN THE SEAS
OVER THE WEEKEND AND INTO NEXT WEEK AS THE WIND VEERS TO A MORE
NORTH TO NORTHEAST DIRECTION. WIND SPEEDS ARE ANTICIPATED TO
REMAIN AT 15 KNOTS OR LESS HOWEVER AND SEAS WILL REMAIN WELL BELOW
ADVISORY CRITERIA.
FIRE WEATHER...NO PROBLEMS OR CONCERNS IN THE SHORT TERM. THERE
WILL BE SOME LOWER RELATIVE HUMIDITIES OVER THE WEEKEND BUT AT
THIS TIME IT LOOKS LIKE THEY WILL REMAIN ABOVE 35 PERCENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 74 87 72 / 50 30 30 20
FORT LAUDERDALE 86 76 87 75 / 50 30 20 20
MIAMI 88 75 88 75 / 50 30 20 20
NAPLES 87 71 86 72 / 50 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS MIAMI FL
724 AM EDT THU OCT 18 2012
.AVIATION...PLENTY OF LINGERING LOW-LEVEL MOISTURE AND CLOUD
COVERAGE WITH BASES RANGING FROM 6-10 KFT WILL REMAIN IN PLACE THIS
MORNING. SOME OF THE INTERIOR AREAS MAY EVEN EXPERIENCE BRIEF
PERIODS WITH REDUCED VISIBILITIES IF ANY OF THIS CLOUD COVERAGE
CLEARS...WITH THE BEST CHANCE INLAND AWAY FROM THE IMMEDIATE COAST.
AS THE DAY PROGRESSES...PLENTY OF LOW-LEVEL MOISTURE UP TO 10-13 KFT
COMBINED WITH WHAT IS LEFT OF AN OLD FRONTAL BOUNDARY WILL KEEP THE
RAIN CHANCES IN THE FORECAST TODAY. THE LATEST WRF AND HRRR MODEL
REFLECTIVITIES INDICATE MAINLY SCATTERED SHOWERS REMAINING POSSIBLE
ONCE AGAIN THROUGH THE LATE MORNING AND AFTERNOON PERIODS. WESTERLY
DEEP LAYER STEERING FLOW WILL FAVOR THE BEST SHOWER COVERAGE ACROSS
THE INTERIOR AND EASTERN HALF OF THE PENINSULA...SIMILAR TO
YESTERDAY.
&&
.PREV DISCUSSION... /ISSUED 244 AM EDT THU OCT 18 2012/
DISCUSSION...LARGE SCALE MID LEVEL TROUGH IS CURRENTLY CENTERED
OVER THE UPPER MISSISSIPPI VALLEY. A SHORT WAVE TROUGH EMBEDDED IN
THIS FLOW MOVED ACROSS SOUTH FLORIDA WEDNESDAY AFTERNOON
GENERATING SOME HEAVY THUNDERSTORMS ACROSS THE NORTHEAST PORTION
OF THE REGION WITH ISOLATED LOCATIONS RECEIVING OVER FOUR INCHES
OF RAINFALL. THIS TROUGH HAS LIFTED TO THE NORTHEAST WHILE AT THE
SURFACE, A WEAK BOUNDARY IS LOCATED JUST OFF THE SOUTHEAST COAST.
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE BEING GENERATED
ALONG THE BOUNDARY. ANOTHER WEAKER SHORT WAVE TROUGH IS LOCATED
OVER THE CENTRAL GULF OF MEXICO WHICH IS SOMEWHAT EVIDENT ON WATER
VAPOR IMAGERY. THE GFS, NAM AND ECMWF ALL DEPICT THIS FEATURE BUT
THE NAM HAS A MORE PRONOUNCED TROUGH AND THUS YIELDS THE HIGHEST
POPS. MUCH DRIER AIR ABOVE 10-15K FEET IS CURRENTLY MOVING INTO
THE REGION BEHIND THE EXITING TROUGH. WHILE THERE WILL BE SOME
INCREASE IN MOISTURE WITH THE SECONDARY TROUGH, IT WOULD APPEAR
THE NAM IS SUFFERING ONCE AGAIN FROM MESOSCALE BIAS. THE TROUGH
AXIS WILL CONTINUE THE SOUTHWEST STEERING FLOW ACROSS SOUTH
FLORIDA SO ANYTHING THAT DEVELOPS OVER THE INTERIOR WILL MOVE
AGAIN TOWARDS THE EAST COAST METRO AREA. THE RAPID REFRESH WHICH
PERFORMED VERY WELL WITH YESTERDAY`S CONVECTION AND ITS CURRENT
RUN GOES OUT THROUGH 18Z, SHOWS SOME DEVELOPMENT BEGINNING AROUND
17Z BUT DOES NOT GET TOO AGGRESSIVE. SO THAT BEING SAID HAVE LEANED
CLOSER TO THE MAV NUMBERS WHICH IS QUITE A BIT LESS FROM THE MET
GUIDANCE. ALL MODEL GUIDANCE NOW SHOWS THE MAIN TROUGH LIFTING TO
THE NORTHEAST THROUGH SATURDAY AS A STRONG TROUGH DEVELOPS IN THE
NORTH PACIFIC. THIS WILL ALLOW FOR THE DRIER AIR MASS TO FILTER
DOWN ACROSS THE PENINSULA ON SATURDAY INTO EARLY NEXT WEEK WITH
DEW POINTS ALSO DROPPING INTO THE 60S. SO A COUPLE MORE DAYS OF
THE HIGHER HUMIDITY AND MORE PLEASANT CONDITIONS FOR THE WEEKEND
AND AT LEAST EARLY NEXT WEEK.
MARINE...TRANQUIL WIND AND SEAS ARE EXPECTED THROUGH THE
REMAINDER OF THIS WEEK AND THEN ONLY A SLOW INCREASE IN THE SEAS
OVER THE WEEKEND AND INTO NEXT WEEK AS THE WIND VEERS TO A MORE
NORTH TO NORTHEAST DIRECTION. WIND SPEEDS ARE ANTICIPATED TO
REMAIN AT 15 KNOTS OR LESS HOWEVER AND SEAS WILL REMAIN WELL BELOW
ADVISORY CRITERIA.
FIRE WEATHER...NO PROBLEMS OR CONCERNS IN THE SHORT TERM. THERE
WILL BE SOME LOWER RELATIVE HUMIDITIES OVER THE WEEKEND BUT AT
THIS TIME IT LOOKS LIKE THEY WILL REMAIN ABOVE 35 PERCENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 74 87 72 / 40 30 30 20
FORT LAUDERDALE 86 76 87 75 / 40 30 20 20
MIAMI 88 75 88 75 / 40 30 20 20
NAPLES 87 71 86 72 / 30 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
743 AM EDT THU OCT 18 2012
.PREV DISCUSSION... /ISSUED 330 AM EDT THU OCT 18 2012/
SHORT TERM /TODAY THROUGH FRIDAY/...
NAM/GFS/ECMWF IN DECENT AGREEMENT THROUGH THE SHORT TERM...SO WENT
WITH A GENERAL BLEND FOR MOST ELEMENTS. LARGE MID LEVEL LOW SPINNING
OVER THE US/CANADA BORDER CONTINUES TO DEEPEN AND PROPAGATE
SOUTHEAST /500MB 00Z UA ANALYSIS HAD MORE HEIGHT FALLS DOWNSTREAM OF
THE LOW THAN HEIGHT RISES UPSTREAM/...AS COLD FRONT STRETCHING FROM
THE OCCLUDED SURFACE LOW SWEEPS ACROSS THE MISSISSIPPI VALLEY. THE
MAIN CONCERN FOR THE PERIOD REMAINS CONVECTION TRENDS FOR TODAY.
LINE OF SHOWERS AND THUNDERSTORMS CURRENTLY STRETCHED FROM MIDDLE
TENNESSEE THROUGH ALABAMA AT AFD TIME...WELL AHEAD OF THE COLD
FRONT...AND SHOULD REACH EXTREME NORTHWEST ZONES WITHIN THE HOUR.
INSTABILITY IS MINIMAL WITH NO SBCAPE SHOWING UP IN MESOANALYSIS...
AND MUCAPE VALUES AT BEST AROUND 250 J/KG...SO THE DRIVING FORCE
BEHIND THE CONVECTION IS SIMPLY THE SYNOPTIC SCALE LIFT...OF WHICH
THERE IS PLENTY. MOST HIRES GUIDANCE REALLY BREAKS THE SYSTEM DOWN
AS IT MOVES INTO GEORGIA...THOUGH THE HRRR DOES KEEP SOME SEMBLANCE
OF ORGANIZED CONVECTION. LIGHTNING ACTIVITY HAS DECREASED IN THE
LINE OVER THE LAST HOUR OR SO. SREF GUIDANCE IS HARD-PRESSED TO
BRING ANY CAPE INTO THE AREA UNTIL THIS AFTERNOON.
SO WITH THAT SAID...HAVE SORT OF TAKEN A COMPROMISE BETWEEN
EXTRAPOLATING WHAT IS ALREADY OUT THERE AND THE SUITE OF HIRES
GUIDANCE. BRING CATEGORICAL POPS INTO NORTHWEST GEORGIA OVER THE
NEXT FEW HOURS WITH DEFINITE THUNDER AT THE ONSET...THEN DECREASE
THUNDER WORDING AS PRECIPITATION SPREADS TOWARD THE METRO AREA BY
12Z. BROUGHT ADDITIONAL THUNDER BACK IN THIS AFTERNOON ACROSS
SOUTHERN ZONES AS INSTABILITY INCREASES WITH AFTERNOON HEATING. NO
REAL CONCERN WITH SEVERE WEATHER AS BEST SHEAR WILL REMAIN TO OUR
NORTH AND NORTHEAST TODAY...BUT CANNOT TOTALLY RULE OUT THE
POSSIBILITY OF AN ISOLATED STRONG TO POSSIBLY SEVERE THUNDERSTORM
ACROSS CENTRAL GEORGIA THIS AFTERNOON. GUSTY WINDS WILL BE THE MAIN
THREAT. OTHERWISE...FOR THE MOST PART LOOKS LIKE A QUICK SHOT OF
RAIN...WITH HIGHEST AMOUNTS NORTHWEST POSSIBLY UP TO A HALF INCH.
COLD FRONT SWEEPS THROUGH BEHIND THE AREA OF RAIN...WITH DRIER AIR
MOVING IN BEHIND IT. WHILE MASS FIELDS REMAIN VERY SIMILAR...MORE
DIFFERENCES BEGIN TO CREEP IN BETWEEN THE NAM AND GFS...WITH MET
GUIDANCE REMAINING A LITTLE MORE MOIST AND THUS A LITTLE WARMER
OVERNIGHT...WITH WARMER TEMPS ON FRIDAY AS WELL. AGAIN...LEANED
GENERALLY TOWARD A BLEND BUT LEANED SLIGHTLY ON THE COOLER SIDE. LOW
TEMPS TONIGHT IN SOME AREAS MAY FLIRT WITH THE UPPER 30S. THIS WILL
BE HEAVILY DEPENDENT ON DEWPOINTS...AND LOOKING UPSTREAM BEHIND THE
FRONT THE DEWPOINTS ARE QUITE DRY. OBVIOUSLY SOME MODIFICATION OF
THE AIRMASS CAN BE EXPECTED...BUT EITHER WAY IT LOOKS LIKE TONIGHT
WILL PROBABLY HAVE THE COLDEST TEMPS OF THE SEASON THUS FAR.
OTHER ITEM OF NOTE WILL BE WINDS IN THE MOUNTAINS ON FRIDAY. AS THE
LOW DIGS SOUTHEAST TOWARD THE GREAT LAKES TODAY AND FRIDAY...THERE
MIGHT BE ENOUGH OF A GRADIENT IN THE MOUNTAINS FRIDAY AFTERNOON
BEFORE THE SURFACE HIGH BEGINS TO BUILD IN FOR POSSIBLE WIND
ADVISORY CRITERIA. TOO EARLY AT THIS POINT BUT WILL REEVALUATE WITH
LATER FORECASTS.
TDP
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE LONG TERM LOOKS TO HAVE MUCH LESS ACTIVITY IN STORE THAN THE
SHORT TERM...AS A DRY FORECAST DOMINATED BY HIGH PRESSURE IS ON TAP.
GUIDANCE IS IN GENERAL AGREEMENT WITH A WEAK SHORTWAVE PUSHING
THROUGH THE FORECAST AREA FRIDAY NIGHT AS IT ROTATES AROUND THE
BROAD UPPER CLOSED LOW CENTERED OVER THE GREAT LAKES. HOWEVER...THIS
ENERGY SHOULD BE TOO REMOVED FROM THE MOISTURE FIELD NORTH OF THE
AREA TO TRANSLATE TO ANY PRECIP CHANCES AND THE UPPER TROUGH AXIS
SHOULD BE EAST OF THE AREA BY LATER SATURDAY...THEREFORE WILL KEEP
DRY CONDITIONS AS THE UPPER RIDGE BUILDS IN FOR NEXT WEEK. MEX
GUIDANCE TEMPS CONTINUE TO LOOK TOO COOL SO HAVE RAISED A BIT
BASED ON PREVIOUS TRENDS...KEEPING MUCH OF THE AREA NEAR
SEASONABLE VALUES TO SLIGHTLY ABOVE NORMAL FROM SUNDAY ONWARD.
BAKER
&&
.AVIATION...
12Z UPDATE...
SHRA MOVING OUT OF THE ATL METRO AREA...BEGINNING TO AFFECT OTHER
TAFS AT 12Z. MVFR CIGS ALSO MOVING IN FROM BOTH THE NE AND THE
NW...HAVE INCLUDED IT IN THE NORTHERN TAFS EXCEPT ATL FOR THIS
MORNING. STILL EXPECT THE WIND SHIFT AROUND 14Z WITH CLEARING
THEREAFTER NORTH. FOR MCN AND CSG...MAY STILL SEE CONVECTION
THROUGH THE AFTERNOON HOURS OFF AND ON. FOR NOW HAVE ONLY KEPT
VCSH BUT WILL MONITOR IN CASE TEMPO TSRA IS NEEDED.
//ATL CONFIDENCE...12Z UPDATE...
HIGH ON WINDS...PRECIP ENDING...AND CIGS AFTER 18Z.
MEDIUM ON CIGS THIS MORNING.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 72 46 73 47 / 80 10 5 5
ATLANTA 72 51 73 47 / 40 10 0 5
BLAIRSVILLE 66 42 66 40 / 10 5 0 5
CARTERSVILLE 72 40 72 44 / 10 5 0 5
COLUMBUS 79 51 76 49 / 80 10 5 5
GAINESVILLE 69 48 71 46 / 50 5 0 5
MACON 79 47 77 46 / 60 20 5 5
ROME 73 39 71 43 / 10 5 0 5
PEACHTREE CITY 74 41 74 43 / 50 10 0 5
VIDALIA 81 61 79 53 / 50 30 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
746 AM EDT THU OCT 18 2012
.SYNOPSIS...
A DEEP CLOSED LOW ALOFT IN THE UPPER MISSISSIPPI VALLEY WILL
MOVE SLOWLY EASTWARD ACROSS THE GREAT LAKES REGION...CONTINUING
TO INFLUENCE THE WEATHER PATTERN IN PENNSYLVANIA THROUGH THE FIRST
PART OF THE WEEKEND. THE MATURE SURFACE CYCLONE ASSOCIATED WITH
THIS SYSTEM WILL OCCLUDE OVER THE UPPER MIDWEST AND BECOME
VERTICALLY STACKED. A COLD FRONT WILL SHIFT THROUGH THE UPPER
OHIO VALLEY BY LATE MORNING AND CONTINUE TO PUSH EASTWARD ACROSS
THE APPALACHIANS THROUGH TONIGHT. THE UPPER LEVEL SYSTEM WILL
LIFT AWAY FROM THE REGION ON SUNDAY...REPLACED BY HIGH PRESSURE
WHICH WILL BRING IMPROVING CONDITIONS AND WARMER TEMPERATURES INTO
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT IR SATL TRENDS CONTINUE TO INDICATE EXPANSION OF LOW
STRATUS DECK OVER THE CENTRAL RIDGE AND VALLEY REGION. HAVE
INCREASED GRIDDED CLOUD COVER IN THIS AREA THRU MID MORNING. LYRD
MID AND HIGH CLOUDS WILL BEGIN TO OVERSPREAD WRN PA THRU 12Z AHEAD
OF APPROACHING COLD FRONT...WHICH JUST PASSED KIND AS OF 09Z.
STRONG UPPER JET AND EMBEDDED SHORTWAVE TROF ROUNDING BASE OF DEEP
CLOSED LOW OVER THE UPPER MIDWEST WILL DRIVE THE COLD FRONT EWD
THRU THE UPPER OH VLY AND ACRS THE APPALACHIANS THRU TONIGHT. THE
MAIN FCST CONCERNS IN THE NEAR TERM WILL BE TIMING OF FRONTAL RAINS
AND POTENTIAL SVR WX/DMGG WIND THREAT ASSOC WITH NARROW LOW-TOPPED
CONVECTIVE LINE.
THE LATEST HRRR WEAKENS THE ONGOING CONVECTIVE FRONTAL BAND MOVG
EWD THRU THE MID OH/TN VLY. MDL DATA INDICATES NEWD MSTR RETURN
AHEAD OF THE APPROACHING FRONTAL BAND WILL BE PINCHED-
OFF...RESULTING IN LIMITED INSTABILITY/CAPE OVER CENTRAL PA. THAT
SAID...MARGINAL DIURNAL HEATING COMBINED WITH STRONG UPPER LEVEL
DIVERGENCE - IN THE LEFT EXIT REGION OF 100+KT JET MAX - MAY BE
SUFFICIENT TO SUPPORT AN INCREASE IN INTENSITY OF THIN CONVECTIVE
LINE ALONG/AHEAD OF THE COLD FRONT AS IT MOVES INTO WRN PA THIS
AFTN. SPC HAS MODIFIED/DECREASED THEIR SLIGHT RISK AREA TO ONLY
INCLUDE ONLY SW PA...LAUREL HIGHLANDS AND THE S-CENTRAL MTNS. THEY
ADMIT THAT THE SET-UP IS BORDERLINE FOR SLGT RISK AND CONFIDENCE
IS LOW...HOWEVER MESO MDLS SEEM TO SUGGEST THAT THE DYNAMIC
FORCING MAY OVERCOME THE LACK OF INSTABILITY/MOISTURE TO PRODUCE A
NARROW LOW-TOPPED SQUALL LINE FEATURE. THESE CONVECTIVELY
ENHANCED SYSTEMS USUALLY HAVE THE CAPABILITY TO PRODUCE WIND
DAMAGE WITH LITTLE NO CG LIGHTNING. DAYSHIFT WILL NEED TO MONITOR
THE SITUATION AS IT EVOLVES.
CVRG/INTENSITY OF SHOWERS SHOULD STRENGTHEN THIS EVE AND EARLY
TONIGHT AS THE FRONTAL BAND CROSSES THE CENTRAL AND ERN PRTNS OF
THE CWA. A WAVE SHOULD DEVELOP AND RIDE NWD ALONG THE N-S FRONTAL
ZONE...ENHANCING MSTR CONVERGENCE IN AN AXIS OF ABV NORMAL PWATS
EXTENDING NWD FROM THE WRN ATLC. MODELS ARE IN PRETTY GOOD
AGREEMENT IN EMPHASIZING A LCL MAX OVER EAST-CENTRAL PA TONIGHT. DAY
1 AREAL QPF AVGS BTWN 0.25-0.50" IN THE WEST AND 0.50-0.75" IN THE
CENTRAL AND ERN BASINS. WOULD NOT BE SURPRISED TO SEE SOME ISOLD 1+
INCH PT AMTS.
THE FCST BEST-TIMING FOR PCPN...GIVE OR TAKE...IS MID-LATE
AFTN OVR WRN PA...EARLY-MID EVE IN THE CENTRAL MTNS AND LATER TNT
THRU THE PREDAWN HOURS FRI ACRS THE ERN 1/3 OF THE CWA.
DRY SLOT WRAPPING AROUND THE VERTICALLY STACKED SYSTEM SHOULD
BRING AND END PCPN ACRS THE WRN MTNS BY LATE TNT...BUT THE FRONTAL
ZONE WILL SLOW ITS EWD PROGRESSION AS IT APPROACHES THE MID-ATLC
COAST DUE TO STRONG DOWNSTREAM UPPER RIDGE BUILDING OVR THE NRN
ATLC. THIS SHOULD KEEP FRONTAL RAINS GOING THRU THE END OF THE
PERIOD ACRS THE FAR ERN SXNS OF THE CWA...POSSIBLY CONTINUING INTO
EARLY FRIDAY.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
THE BACK EDGE OF THE N-S PCPN AXIS WILL SHIFT ENEWD INTO SRN NEW
ENGLAND EARLY FRIDAY. THE VERTICALLY STACKED LOW SHOULD REACH THE
LAKE ERIE VCNTY BY 12Z SAT. EXPECT SOME SHOWERS AHEAD OF THE UPPER
TROF AXIS MOVG THRU THE UPPER OH VLY...AS COOLER AIR ALOFT BEGINS
TO FILTER INTO THE AREA. THERE SHOULD BE A DRY PERIOD IN BETWEEN
THE DEPARTING FRONTAL BOUNDARY AND APPROACHING CLOSED H5 SYSTEM.
FCST TEMPS ARE ACTUALLY ABV NORMAL ON FRI AS LLVL FLOW REMAINS
FROM THE SOUTH. ALTHOUGH CONSENSUS IS FOR PCPN TO LIFT OUT BY FRI
NGT...SECONDARY HEIGHT FALL CENTER ASSOC WITH ANOTHER S/W PIVOTING
AROUND THE UPPER LOW AND NEARBY JET-ENTRANCE REGION MAY LEAD TO
ADDNL MDT RAINS OVR ERN PA.
SCT TO NMRS SHOWERS ARE EXPECTED INTO SAT NGT AS THE UPPER TROUGH
AND COOL POOL ALOFT MOVES OVERHEAD. THE GFS IS MORE PROGRESSIVE
THAN THE ECMWF...WHICH IS THE SLOWEST OF ALL THE DETERMINISTIC
MODELS TO LIFT THE SYSTEM NWD AWAY FROM THE AREA. THIS THEME
CONTINUES INTO THE SECOND HALF OF THE WEEKEND...WITH THE ECMWF
SHOWING A MORE PESSIMISTIC OUTCOME. ENS DATA SUGGESTS A SOLN
SOMEWHERE IN BTWN THE SLOWER EC AND FASTER GFS FOR SUNDAY.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
HEIGHTS SHOULD BE ON THE RISE BY EARLY NEXT WEEK...IN RESPONSE TO
TROUGHING IN THE PAC NW AND EXTENDING SWD ALONG THE WEST COAST.
HIGH PRES AT THE SFC SHOULD PROVIDE FAIR AND DRY WEATHER ON
MONDAY. BROAD SWLY RETURN FLOW SHOULD BOOST TEMPS ABV LATE OCT
CLIMO VALUES INTO MID-WEEK. AS THE HIGH SINKS SWD INTO THE SE
STATES...AN ELONGATED FRONTAL ZONE MAY DROP FAR ENOUGH SOUTH TO
BRING SOME OPPORTUNITIES FOR PCPN TUE-WED MAINLY OVER THE NRN TIER.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
LOW CLDS JUST EAST OF THE OFFICE.
ADJUSTED 12Z TAFS.
MAIN CHANGE WAS TO ADJUST TAFS THE LAST FEW HOURS
FOR LOWER CLDS MOVING IN FROM THE SE. EXPECT THESE
TO BE AND OUT OF THE EASTERN AREAS THROUGH MID TO
LATE MORNING.
WILL CONTINUE TO MONITOR AND ADJUST AS NEEDED.
DESPITE THE LOW DEWPOINTS...SPOTS LIKE MDT AND LNS WILL
SEE A BIT OF FOG DURING THE NEXT HOUR OR SO.
WHILE WIND FIELDS ARE NOT AS STRONG AS THEY WERE ON SUNDAY
NIGHT...STILL LOOKING AT SOME GUSTY WINDS TODAY...HAVE LLWS
AT BFD...JST...AND IPT. AT BFD AND JST...NEAR BEST LLJ...
WHILE IPT OFTEN GETS A GUSTY SE TO EAST WIND WITH WARM
ADVECTION AND FAIRLY STRONG WIND FIELDS.
SPC HAS THE AREA UNDER A SLIGHT RISK FOR STRONG TO SEVERE
STORMS LATER TODAY...AS THE COLD FRONT MOVES INTO THE AREA.
WILL CONTINUE TO LOOK THE SITUATION OVER.
MUCH OF FRIDAY INTO THE WEEKEND WILL LIKELY BE DRY AND VFR...
BUT MVFR CONDITIONS WITH A FEW SHOWERS WILL BE POSSIBLE...
MAINLY ACROSS THE HIGHER ELEVATIONS LIKE JST AND BFD...AS
THE UPPER LVL LOW MOVES ACROSS THE AREA.
OUTLOOK...
FRI...SHOWERS...MAINLY EARLY...THEN MAINLY VFR.
SAT...MVFR CIGS/SHRA POSS W...VFR ELSEWHERE.
SUN-MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
630 AM EDT THU OCT 18 2012
.SYNOPSIS...
A DEEP CLOSED LOW ALOFT IN THE UPPER MISSISSIPPI VALLEY WILL
MOVE SLOWLY EASTWARD ACROSS THE GREAT LAKES REGION...CONTINUING
TO INFLUENCE THE WEATHER PATTERN IN PENNSYLVANIA THROUGH THE FIRST
PART OF THE WEEKEND. THE MATURE SURFACE CYCLONE ASSOCIATED WITH
THIS SYSTEM WILL OCCLUDE OVER THE UPPER MIDWEST AND BECOME
VERTICALLY STACKED. A COLD FRONT WILL SHIFT THROUGH THE UPPER
OHIO VALLEY BY LATE MORNING AND CONTINUE TO PUSH EASTWARD ACROSS
THE APPALACHIANS THROUGH TONIGHT. THE UPPER LEVEL SYSTEM WILL
LIFT AWAY FROM THE REGION ON SUNDAY...REPLACED BY HIGH PRESSURE
WHICH WILL BRING IMPROVING CONDITIONS AND WARMER TEMPERATURES INTO
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT IR SATL TRENDS CONTINUE TO INDICATE EXPANSION OF LOW
STRATUS DECK OVER THE CENTRAL RIDGE AND VALLEY REGION. HAVE
INCREASED GRIDDED CLOUD COVER IN THIS AREA THRU MID MORNING. LYRD
MID AND HIGH CLOUDS WILL BEGIN TO OVERSPREAD WRN PA THRU 12Z AHEAD
OF APPROACHING COLD FRONT...WHICH JUST PASSED KIND AS OF 09Z.
STRONG UPPER JET AND EMBEDDED SHORTWAVE TROF ROUNDING BASE OF DEEP
CLOSED LOW OVER THE UPPER MIDWEST WILL DRIVE THE COLD FRONT EWD
THRU THE UPPER OH VLY AND ACRS THE APPALACHIANS THRU TONIGHT. THE
MAIN FCST CONCERNS IN THE NEAR TERM WILL BE TIMING OF FRONTAL RAINS
AND POTENTIAL SVR WX/DMGG WIND THREAT ASSOC WITH NARROW LOW-TOPPED
CONVECTIVE LINE.
THE LATEST HRRR WEAKENS THE ONGOING CONVECTIVE FRONTAL BAND MOVG
EWD THRU THE MID OH/TN VLY. MDL DATA INDICATES NEWD MSTR RETURN
AHEAD OF THE APPROACHING FRONTAL BAND WILL BE PINCHED-
OFF...RESULTING IN LIMITED INSTABILITY/CAPE OVER CENTRAL PA. THAT
SAID...MARGINAL DIURNAL HEATING COMBINED WITH STRONG UPPER LEVEL
DIVERGENCE - IN THE LEFT EXIT REGION OF 100+KT JET MAX - MAY BE
SUFFICIENT TO SUPPORT AN INCREASE IN INTENSITY OF THIN CONVECTIVE
LINE ALONG/AHEAD OF THE COLD FRONT AS IT MOVES INTO WRN PA THIS
AFTN. SPC HAS MODIFIED/DECREASED THEIR SLIGHT RISK AREA TO ONLY
INCLUDE ONLY SW PA...LAUREL HIGHLANDS AND THE S-CENTRAL MTNS. THEY
ADMIT THAT THE SET-UP IS BORDERLINE FOR SLGT RISK AND CONFIDENCE
IS LOW...HOWEVER MESO MDLS SEEM TO SUGGEST THAT THE DYNAMIC
FORCING MAY OVERCOME THE LACK OF INSTABILITY/MOISTURE TO PRODUCE A
NARROW LOW-TOPPED SQUALL LINE FEATURE. THESE CONVECTIVELY
ENHANCED SYSTEMS USUALLY HAVE THE CAPABILITY TO PRODUCE WIND
DAMAGE WITH LITTLE NO CG LIGHTNING. DAYSHIFT WILL NEED TO MONITOR
THE SITUATION AS IT EVOLVES.
CVRG/INTENSITY OF SHOWERS SHOULD STRENGTHEN THIS EVE AND EARLY
TONIGHT AS THE FRONTAL BAND CROSSES THE CENTRAL AND ERN PRTNS OF
THE CWA. A WAVE SHOULD DEVELOP AND RIDE NWD ALONG THE N-S FRONTAL
ZONE...ENHANCING MSTR CONVERGENCE IN AN AXIS OF ABV NORMAL PWATS
EXTENDING NWD FROM THE WRN ATLC. MODELS ARE IN PRETTY GOOD
AGREEMENT IN EMPHASIZING A LCL MAX OVER EAST-CENTRAL PA TONIGHT. DAY
1 AREAL QPF AVGS BTWN 0.25-0.50" IN THE WEST AND 0.50-0.75" IN THE
CENTRAL AND ERN BASINS. WOULD NOT BE SURPRISED TO SEE SOME ISOLD 1+
INCH PT AMTS.
THE FCST BEST-TIMING FOR PCPN...GIVE OR TAKE...IS MID-LATE
AFTN OVR WRN PA...EARLY-MID EVE IN THE CENTRAL MTNS AND LATER TNT
THRU THE PREDAWN HOURS FRI ACRS THE ERN 1/3 OF THE CWA.
DRY SLOT WRAPPING AROUND THE VERTICALLY STACKED SYSTEM SHOULD
BRING AND END PCPN ACRS THE WRN MTNS BY LATE TNT...BUT THE FRONTAL
ZONE WILL SLOW ITS EWD PROGRESSION AS IT APPROACHES THE MID-ATLC
COAST DUE TO STRONG DOWNSTREAM UPPER RIDGE BUILDING OVR THE NRN
ATLC. THIS SHOULD KEEP FRONTAL RAINS GOING THRU THE END OF THE
PERIOD ACRS THE FAR ERN SXNS OF THE CWA...POSSIBLY CONTINUING INTO
EARLY FRIDAY.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
THE BACK EDGE OF THE N-S PCPN AXIS WILL SHIFT ENEWD INTO SRN NEW
ENGLAND EARLY FRIDAY. THE VERTICALLY STACKED LOW SHOULD REACH THE
LAKE ERIE VCNTY BY 12Z SAT. EXPECT SOME SHOWERS AHEAD OF THE UPPER
TROF AXIS MOVG THRU THE UPPER OH VLY...AS COOLER AIR ALOFT BEGINS
TO FILTER INTO THE AREA. THERE SHOULD BE A DRY PERIOD IN BETWEEN
THE DEPARTING FRONTAL BOUNDARY AND APPROACHING CLOSED H5 SYSTEM.
FCST TEMPS ARE ACTUALLY ABV NORMAL ON FRI AS LLVL FLOW REMAINS
FROM THE SOUTH. ALTHOUGH CONSENSUS IS FOR PCPN TO LIFT OUT BY FRI
NGT...SECONDARY HEIGHT FALL CENTER ASSOC WITH ANOTHER S/W PIVOTING
AROUND THE UPPER LOW AND NEARBY JET-ENTRANCE REGION MAY LEAD TO
ADDNL MDT RAINS OVR ERN PA.
SCT TO NMRS SHOWERS ARE EXPECTED INTO SAT NGT AS THE UPPER TROUGH
AND COOL POOL ALOFT MOVES OVERHEAD. THE GFS IS MORE PROGRESSIVE
THAN THE ECMWF...WHICH IS THE SLOWEST OF ALL THE DETERMINISTIC
MODELS TO LIFT THE SYSTEM NWD AWAY FROM THE AREA. THIS THEME
CONTINUES INTO THE SECOND HALF OF THE WEEKEND...WITH THE ECMWF
SHOWING A MORE PESSIMISTIC OUTCOME. ENS DATA SUGGESTS A SOLN
SOMEWHERE IN BTWN THE SLOWER EC AND FASTER GFS FOR SUNDAY.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
HEIGHTS SHOULD BE ON THE RISE BY EARLY NEXT WEEK...IN RESPONSE TO
TROUGHING IN THE PAC NW AND EXTENDING SWD ALONG THE WEST COAST.
HIGH PRES AT THE SFC SHOULD PROVIDE FAIR AND DRY WEATHER ON
MONDAY. BROAD SWLY RETURN FLOW SHOULD BOOST TEMPS ABV LATE OCT
CLIMO VALUES INTO MID-WEEK. AS THE HIGH SINKS SWD INTO THE SE
STATES...AN ELONGATED FRONTAL ZONE MAY DROP FAR ENOUGH SOUTH TO
BRING SOME OPPORTUNITIES FOR PCPN TUE-WED MAINLY OVER THE NRN TIER.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
MAIN CHANGE WAS TO ADJUST TAFS THE LAST FEW HOURS
FOR LOWER CLDS MOVING IN FROM THE SE. EXPECT THESE
TO BE AND OUT OF THE EASTERN AREAS THROUGH MID TO
LATE MORNING.
OTHERWISE...NO OTHER MAJOR CHANGES AS OF 10Z.
WILL CONTINUE TO MONITOR AND ADJUST AS NEEDED.
DESPITE THE LOW DEWPOINTS...SPOTS LIKE MDT AND LNS WILL
SEE A BIT OF FOG DURING THE HOURS SURROUNDING SUNRISE.
WHILE WIND FIELDS ARE NOT AS STRONG AS THEY WERE ON SUNDAY
NIGHT...STILL LOOKING AT SOME GUSTY WINDS TODAY...HAVE LLWS
AT BFD...JST...AND IPT. AT BFD AND JST...NEAR BEST LLJ...
WHILE IPT OFTEN GETS A GUSTY SE TO EAST WIND WITH WARM
ADVECTION AND FAIRLY STRONG WIND FIELDS.
SPC HAS THE AREA UNDER A SLIGHT RISK FOR STRONG TO SEVERE
STORMS LATER TODAY...AS THE COLD FRONT MOVES INTO THE AREA.
WILL CONTINUE TO LOOK THE SITUATION OVER.
MUCH OF FRIDAY INTO THE WEEKEND WILL LIKELY BE DRY AND VFR...
BUT MVFR CONDITIONS WITH A FEW SHOWERS WILL BE POSSIBLE...
MAINLY ACROSS THE HIGHER ELEVATIONS LIKE JST AND BFD...AS
THE UPPER LVL LOW MOVES ACROSS THE AREA.
OUTLOOK...
FRI...SHOWERS...MAINLY EARLY...THEN MAINLY VFR.
SAT...MVFR CIGS/SHRA POSS W...VFR ELSEWHERE.
SUN-MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
608 AM EDT THU OCT 18 2012
.SYNOPSIS...
A DEEP CLOSED LOW ALOFT IN THE UPPER MISSISSIPPI VALLEY WILL
MOVE SLOWLY EASTWARD ACROSS THE GREAT LAKES REGION...CONTINUING
TO INFLUENCE THE WEATHER PATTERN IN PENNSYLVANIA THROUGH THE FIRST
PART OF THE WEEKEND. THE MATURE SURFACE CYCLONE ASSOCIATED WITH
THIS SYSTEM WILL OCCLUDE OVER THE UPPER MIDWEST AND BECOME
VERTICALLY STACKED. A COLD FRONT WILL SHIFT THROUGH THE UPPER
OHIO VALLEY BY LATE MORNING AND CONTINUE TO PUSH EASTWARD ACROSS
THE APPALACHIANS THROUGH TONIGHT. THE UPPER LEVEL SYSTEM WILL
LIFT AWAY FROM THE REGION ON SUNDAY...REPLACED BY HIGH PRESSURE
WHICH WILL BRING IMPROVING CONDITIONS AND WARMER TEMPERATURES INTO
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT IR SATL TRENDS CONTINUE TO INDICATE EXPANSION OF LOW
STRATUS DECK OVER THE CENTRAL RIDGE AND VALLEY REGION. HAVE
INCREASED GRIDDED CLOUD COVER IN THIS AREA THRU MID MORNING. LYRD
MID AND HIGH CLOUDS WILL BEGIN TO OVERSPREAD WRN PA THRU 12Z AHEAD
OF APPROACHING COLD FRONT...WHICH JUST PASSED KIND AS OF 09Z.
STRONG UPPER JET AND EMBEDDED SHORTWAVE TROF ROUNDING BASE OF DEEP
CLOSED LOW OVER THE UPPER MIDWEST WILL DRIVE THE COLD FRONT EWD
THRU THE UPPER OH VLY AND ACRS THE APPALACHIANS THRU TONIGHT. THE
MAIN FCST CONCERNS IN THE NEAR TERM WILL BE TIMING OF FRONTAL RAINS
AND POTENTIAL SVR WX/DMGG WIND THREAT ASSOC WITH NARROW LOW-TOPPED
CONVECTIVE LINE.
THE LATEST HRRR WEAKENS THE ONGOING CONVECTIVE FRONTAL BAND MOVG
EWD THRU THE MID OH/TN VLY. MDL DATA INDICATES NEWD MSTR RETURN
AHEAD OF THE APPROACHING FRONTAL BAND WILL BE PINCHED-
OFF...RESULTING IN LIMITED INSTABILITY/CAPE OVER CENTRAL PA. THAT
SAID...MARGINAL DIURNAL HEATING COMBINED WITH STRONG UPPER LEVEL
DIVERGENCE - IN THE LEFT EXIT REGION OF 100+KT JET MAX - MAY BE
SUFFICIENT TO SUPPORT AN INCREASE IN INTENSITY OF THIN CONVECTIVE
LINE ALONG/AHEAD OF THE COLD FRONT AS IT MOVES INTO WRN PA THIS
AFTN. SPC HAS MODIFIED/DECREASED THEIR SLIGHT RISK AREA TO ONLY
INCLUDE ONLY SW PA...LAUREL HIGHLANDS AND THE S-CENTRAL MTNS. THEY
ADMIT THAT THE SET-UP IS BORDERLINE FOR SLGT RISK AND CONFIDENCE
IS LOW...HOWEVER MESO MDLS SEEM TO SUGGEST THAT THE DYNAMIC
FORCING MAY OVERCOME THE LACK OF INSTABILITY/MOISTURE TO PRODUCE A
NARROW LOW-TOPPED SQUALL LINE FEATURE. THESE CONVECTIVELY
ENHANCED SYSTEMS USUALLY HAVE THE CAPABILITY TO PRODUCE WIND
DAMAGE WITH LITTLE NO CG LIGHTNING. DAYSHIFT WILL NEED TO MONITOR
THE SITUATION AS IT EVOLVES.
CVRG/INTENSITY OF SHOWERS SHOULD STRENGTHEN THIS EVE AND EARLY
TONIGHT AS THE FRONTAL BAND CROSSES THE CENTRAL AND ERN PRTNS OF
THE CWA. A WAVE SHOULD DEVELOP AND RIDE NWD ALONG THE N-S FRONTAL
ZONE...ENHANCING MSTR CONVERGENCE IN AN AXIS OF ABV NORMAL PWATS
EXTENDING NWD FROM THE WRN ATLC. MODELS ARE IN PRETTY GOOD
AGREEMENT IN EMPHASIZING A LCL MAX OVER EAST-CENTRAL PA TONIGHT. DAY
1 AREAL QPF AVGS BTWN 0.25-0.50" IN THE WEST AND 0.50-0.75" IN THE
CENTRAL AND ERN BASINS. WOULD NOT BE SURPRISED TO SEE SOME ISOLD 1+
INCH PT AMTS.
THE FCST BEST-TIMING FOR PCPN...GIVE OR TAKE...IS MID-LATE
AFTN OVR WRN PA...EARLY-MID EVE IN THE CENTRAL MTNS AND LATER TNT
THRU THE PREDAWN HOURS FRI ACRS THE ERN 1/3 OF THE CWA.
DRY SLOT WRAPPING AROUND THE VERTICALLY STACKED SYSTEM SHOULD
BRING AND END PCPN ACRS THE WRN MTNS BY LATE TNT...BUT THE FRONTAL
ZONE WILL SLOW ITS EWD PROGRESSION AS IT APPROACHES THE MID-ATLC
COAST DUE TO STRONG DOWNSTREAM UPPER RIDGE BUILDING OVR THE NRN
ATLC. THIS SHOULD KEEP FRONTAL RAINS GOING THRU THE END OF THE
PERIOD ACRS THE FAR ERN SXNS OF THE CWA...POSSIBLY CONTINUING INTO
EARLY FRIDAY.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
THE BACK EDGE OF THE N-S PCPN AXIS WILL SHIFT ENEWD INTO SRN NEW
ENGLAND EARLY FRIDAY. THE VERTICALLY STACKED LOW SHOULD REACH THE
LAKE ERIE VCNTY BY 12Z SAT. EXPECT SOME SHOWERS AHEAD OF THE UPPER
TROF AXIS MOVG THRU THE UPPER OH VLY...AS COOLER AIR ALOFT BEGINS
TO FILTER INTO THE AREA. THERE SHOULD BE A DRY PERIOD IN BETWEEN
THE DEPARTING FRONTAL BOUNDARY AND APPROACHING CLOSED H5 SYSTEM.
FCST TEMPS ARE ACTUALLY ABV NORMAL ON FRI AS LLVL FLOW REMAINS
FROM THE SOUTH. ALTHOUGH CONSENSUS IS FOR PCPN TO LIFT OUT BY FRI
NGT...SECONDARY HEIGHT FALL CENTER ASSOC WITH ANOTHER S/W PIVOTING
AROUND THE UPPER LOW AND NEARBY JET-ENTRANCE REGION MAY LEAD TO
ADDNL MDT RAINS OVR ERN PA.
SCT TO NMRS SHOWERS ARE EXPECTED INTO SAT NGT AS THE UPPER TROUGH
AND COOL POOL ALOFT MOVES OVERHEAD. THE GFS IS MORE PROGRESSIVE
THAN THE ECMWF...WHICH IS THE SLOWEST OF ALL THE DETERMINISTIC
MODELS TO LIFT THE SYSTEM NWD AWAY FROM THE AREA. THIS THEME
CONTINUES INTO THE SECOND HALF OF THE WEEKEND...WITH THE ECMWF
SHOWING A MORE PESSIMISTIC OUTCOME. ENS DATA SUGGESTS A SOLN
SOMEWHERE IN BTWN THE SLOWER EC AND FASTER GFS FOR SUNDAY.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
HEIGHTS SHOULD BE ON THE RISE BY EARLY NEXT WEEK...IN RESPONSE TO
TROUGHING IN THE PAC NW AND EXTENDING SWD ALONG THE WEST COAST.
HIGH PRES AT THE SFC SHOULD PROVIDE FAIR AND DRY WEATHER ON
MONDAY. BROAD SWLY RETURN FLOW SHOULD BOOST TEMPS ABV LATE OCT
CLIMO VALUES INTO MID-WEEK. AS THE HIGH SINKS SWD INTO THE SE
STATES...AN ELONGATED FRONTAL ZONE MAY DROP FAR ENOUGH SOUTH TO
BRING SOME OPPORTUNITIES FOR PCPN TUE-WED MAINLY OVER THE NRN TIER.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
LOOKING AT MAINLY VFR CONDITIONS OVERNIGHT.
SKIES WILL BE MAINLY CLEAR OVERNIGHT...WITH JUST SOME HIGH
CLDS TO THE WEST.
DESPITE THE LOW DEWPOINTS...SPOTS LIKE MDT AND LNS COULD SEE
A BIT OF FOG DURING THE HOURS SURROUNDING SUNRISE.
WHILE WIND FIELDS ARE NOT AS STRONG AS THEY WERE ON SUNDAY
NIGHT...STILL LOOKING AT SOME GUSTY WINDS TODAY...HAVE LLWS
AT BFD...JST...AND IPT. AT BFD AND JST...NEAR BEST LLJ...
WHILE IPT OFTEN GETS A GUSTY SE TO EAST WIND WITH WARM
ADVECTION AND FAIRLY STRONG WIND FIELDS.
SPC HAS THE AREA UNDER A SLIGHT RISK FOR STRONG TO SEVERE
STORMS LATER TODAY...AS THE COLD FRONT MOVES INTO THE AREA.
WILL CONTINUE TO LOOK THE SITUATION OVER.
MUCH OF FRIDAY INTO THE WEEKEND WILL LIKELY BE DRY AND VFR...
BUT MVFR CONDITIONS WITH A FEW SHOWERS WILL BE POSSIBLE...
MAINLY ACROSS THE HIGHER ELEVATIONS LIKE JST AND BFD...AS
THE UPPER LVL LOW MOVES ACROSS THE AREA.
OUTLOOK...
FRI...SHOWERS...MAINLY EARLY...THEN MAINLY VFR.
SAT...MVFR CIGS/SHRA POSS W...VFR ELSEWHERE.
SUN-MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1110 AM MDT THU OCT 18 2012
.AVIATION...
DRY NORTHWESTERLY UPPER FLOW ALOFT WILL BE CONDUCIVE TO GUSTY
WINDS AT TIMES...DRY CONDITIONS AND GENERALLY CLEAR SKIES AT
THE KALS...KCOS AND KPUB TAF SITES THROUGH TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 402 AM MDT THU OCT 18 2012/
SHORT TERM...
(TODAY AND TONIGHT)
SO FAR TEMPS OVR THE SERN PLAINS HAVE NOT GONE BELOW FREEZING AND
HAVE BEEN IN THE MID AND UPR 30S...BUT DEW POINTS REMAIN QUITE LOW
AND THERE IS STILL TIME FOR TEMPS TO FALL BELOW FREEZING THIS
MORNING. THUS WL LEAVE THE FREEZE WARNING IN EFFECT.
MAIN CONCERN TODAY IS THE POTENTIAL FOR RED FLAG CONDITIONS. WITH A
DRY AIR MASS IN PLACE OVR THE AREA...DEW POINTS TODAY WL BE QUITE
LOW AND MIN RH VALUES ARE EXPECTED TO BE BELOW 15 PERCENT AT THE
LOWER ELEVATIONS. BRISK DRY NW FLOW WL BE FOUND OVR THE AREA
TODAY...ALTHOUGH GENERALLY NOT QUITE AS STRONG AS YESTERDAY IN MOST
AREAS. THE STRONGEST GRADIENT WL BE OVR THE FAR SERN PLAINS...AND
IT LOOKS LIKE GUSTS WL MEET RED FLAG CRITERIA THIS AFTERNOON OVR
KIOWA COUNTY AND A GOOD PORTION OF PROWERS COUNTY...SO WL ISSUE RED
FLAG WARNING. THE HRRR AND LOCAL WRF ARE SHOWING GUSTS ALSO MEETING
CRITERIA OVR NRN EL PASO COUNTY...MAINLY EAST OF THE INTERSTATE SO
WL ALSO ISSUE A WARNING FOR THIS AREA. THERE ARE TWO OTHER AREAS OF
CONCERN...THE FAR EASTERN AREAS OF SRN EL PASO COUNTY (FIRE ZONE
227) AND THE NRN PORTIONS OF THE SAN LUIS VALLEY (FIRE ZONE
224)...WHERE GUSTS ARE ALSO EXPECTED TO REACH RED FLAG WARNING
CRITERIA THIS AFTERNOON. THE PORTIONS OF THESE FIRE ZONES WHERE THE
GUSTS WL PROBABLY MEET CRITERIA SEEM TOO LOCALIZED TO ISSUE RED FLAG
WARNINGS FOR THE ENTIRE ZONE...SO WL NOT ISSUE A HIGHLIGHT AT THIS
TIME.
FOR TONIGHT...THE WEATHER WL REMAIN DRY WITH LITTLE IF ANY CLOUDS.
SOME AREAS...MAINLY ALONG THE ARKANSAS RIVER VALLEY...MAY AGAIN SEE
LOW TEMPS FALL BELOW 32 DEGREES. WL HAVE TO WAIT AN SEE IF WE GET A
FREEZE THIS MORNING TO SEE IF A HIGHLIGHT MAY BE NEEDED TONIGHT.
LONG TERM...
(FRIDAY THROUGH WEDNESDAY)
..WARM AND DRY THROUGH THE WEEKEND...
FRIDAY-SUNDAY...MODELS REMAIN IN GOOD AGREEMENT THROUGH THE WEEKEND
AS MODERATING NORTHWEST FLOW ALOFT ACROSS THE REGION ON FRIDAY
BECOMES MORE WEST TO SOUTHWEST SATURDAY AND INCREASES AGAIN ON
SUNDAY WITH PAC NORTHWEST ENERGY DIGGING ACROSS THE GREAT BASIN AND
NORTHERN TIER OF STATES. MODELS ALSO INDICATING THE WEAKENING
REMNANTS OF POST TROPICAL SYSTEM PAUL LIFTING OUT ACROSS THE
DESERT SOUTHWEST ON SUNDAY. WARMING ALOFT PROGGED ACROSS THE AREA
FRIDAY AND SATURDAY ALONG WITH DOWNSLOPE FLOW WILL ALLOW FOR
TEMPERATURES TO WARM BACK TO ABOVE SEASONAL AVERAGES...ESPECIALLY
ON SATURDAY WITH HIGHS EXPECTED TO BE IN THE 70S AND 80S ACROSS
THE EASTERN PLAINS WITH MAINLY 50S AND 60S ACROSS THE HIGHER
TERRAIN. DEVELOPING DOWNSLOPE FLOW AND THE WARMING ALOFT WILL ALSO
ALLOW FOR WARMER OVERNIGHT LOWS...ESPECIALLY OVER AND NEAR THE
HIGHER TERRAIN. A WEAK NORTHERLY SURGE/COLD FRONT AND COOLING
ALOFT AHEAD OF PAC NORTHWEST TROUGH WILL BRING ONLY SLIGHTLY
COOLER TEMPERATURES ACROSS THE AREA ON SUNDAY.
MONDAY-WEDNESDAY...LESSER CONFIDENCE FORECAST...ESPECIALLY FOR THE
MIDDLE OF THE WEEK AND BEYOND...WITH MODELS DIFFERING ON AMPLITUDE
AND MOVEMENT OF PACIFIC ENERGY DIGGING INTO THE GREAT BASIN AND
ROCKIES. MODELS DO AGREE THAT THE REMNANTS OF THE TROPICAL SYSTEM TO
REMAIN WELL SOUTH OF THE AREA AS IT CONTINUES TO WEAKEN AND LIFT OUT
ACROSS SOUTHERN NEW MEXICO AND THE SOUTHERN HIGH PLAINS.
THE LATEST GFS REMAINS THE DEEPEST SOLUTION WITH MODERATE AND MAINLY
DRY SOUTHWEST FLOW ACROSS THE STATE THROUGH WEDNESDAY WITH A STAND
UP PACIFIC COLD FRONT MOVING ACROSS THE STATE WEDNESDAY AND WEDNESDAY
NIGHT. THE ECMWF IS FASTER AND LESS AMPLIFIED WITH THE SYSTEM AND
MOVES THE FRONT ACROSS THE AREA MONDAY NIGHT AND TUESDAY WITH A
SECONDARY SURGE OF COLD AIR MOVING ACROSS THE AREA WEDNESDAY NIGHT
AND THURSDAY. AT ANY RATE...PATTERN WOULD SUGGEST BEST CHANCES OF
PRECIP TO BE ACROSS THE HIGHER TERRAIN ALONG AND WEST OF THE
CONTDVD WITH TEMPERATURES SLOWLY COOLING BACK TO AT OR BELOW
SEASONAL AVERAGES BE THE MIDDLE OF THE WEEK. -MW
AVIATION...
WITH DRY NW FLOW IN PLACE...FEW IS ANY CLOUDS ARE EXPECTED TODAY AND
TONIGHT AND THUS VFR CONDITIONS WL BE FOUND ACRS THE AREA. SOME
AREAS WL SEE BREEZY NORTHWEST WINDS TODAY. KCOS COULD SEE GUSTS NR
20 KTS THIS AFTERNOON...WITH WINDS AT KALS AND KPUB EXPECTED TO NOT
BE QUITE AS STRONG.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ226-234-236.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
128 PM EDT THU OCT 18 2012
.AVIATION...VFR WILL PREVAIL. A FEW TSRA IS POSSIBLE ACROSS THE
EAST COAST TERMINALS SO MAINTAINED VCTS, ALTHOUGH THIS RISK MAY
HAVE LOWERED A BIT DUE TO THE FACT THAT LOW LEVEL WINDS HAVE
INCREASED OUT OF THE SOUTHWEST AS PER ACARS DATA. THIS WILL LIKELY
KEEP SURFACE WINDS PREVAILING OUT OF THE SSW, BUT DIFFICULT WIND
FORECAST AS SOME OBS CONTINUE SE. LIGHT WINDS, TRANQUIL CONDITIONS
WILL PREVAIL TONIGHT WITH A FEW SHOWERS POSSIBLE ON FRI, AND MAYBE
A TSTORM. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 1000 AM EDT THU OCT 18 2012/
UPDATE...
UPDATED THE SHORT TERM FORECAST TO INCREASE THE POPS ACROSS THE
REGION. THE 12Z SOUNDING AND OTHER REGIONAL PWAT REPORTS INDICATE
AN INCREASING TREND IN MOISTURE ACROSS THE REGION WITH REGIONAL
PWATS NEAR 2 INCHES. IN ADDITION THE RECENT GUIDANCE AND RECENT
WATER VAPOR IMAGERY CONTINUE TO INDICATE A MID TO UPPER LEVEL
SHORT WAVE ENTERING THE EASTERN GULF AND FLORIDA STRAITS. AND EARLIER
THIS MORNING THERE WAS CONSIDERABLE CONVECTION IN THE VICINITY OF
THE CENTRAL FLORIDA KEYS. GIVEN ALL THESE FACTORS...THERE COULD BE
ISOLATED AREAS OF HEAVY RAINFALL ALTHOUGH THUNDERSTORM ACTIVITY IS
EXPECTED TO BE ISOLATED. THE CONVECTION IS MAINLY EXPECTED TO
INCREASE DURING THE EARLY AFTERNOON THROUGH THE EVENING HOURS.
60
PREV DISCUSSION... /ISSUED 724 AM EDT THU OCT 18 2012/
AVIATION...PLENTY OF LINGERING LOW-LEVEL MOISTURE AND CLOUD
COVERAGE WITH BASES RANGING FROM 6-10 KFT WILL REMAIN IN PLACE THIS
MORNING. SOME OF THE INTERIOR AREAS MAY EVEN EXPERIENCE BRIEF
PERIODS WITH REDUCED VISIBILITIES IF ANY OF THIS CLOUD COVERAGE
CLEARS...WITH THE BEST CHANCE INLAND AWAY FROM THE IMMEDIATE COAST.
AS THE DAY PROGRESSES...PLENTY OF LOW-LEVEL MOISTURE UP TO 10-13 KFT
COMBINED WITH WHAT IS LEFT OF AN OLD FRONTAL BOUNDARY WILL KEEP THE
RAIN CHANCES IN THE FORECAST TODAY. THE LATEST WRF AND HRRR MODEL
REFLECTIVITIES INDICATE MAINLY SCATTERED SHOWERS REMAINING POSSIBLE
ONCE AGAIN THROUGH THE LATE MORNING AND AFTERNOON PERIODS. WESTERLY
DEEP LAYER STEERING FLOW WILL FAVOR THE BEST SHOWER COVERAGE ACROSS
THE INTERIOR AND EASTERN HALF OF THE PENINSULA...SIMILAR TO
YESTERDAY.
PREV DISCUSSION... /ISSUED 244 AM EDT THU OCT 18 2012/
DISCUSSION...LARGE SCALE MID LEVEL TROUGH IS CURRENTLY CENTERED
OVER THE UPPER MISSISSIPPI VALLEY. A SHORT WAVE TROUGH EMBEDDED IN
THIS FLOW MOVED ACROSS SOUTH FLORIDA WEDNESDAY AFTERNOON
GENERATING SOME HEAVY THUNDERSTORMS ACROSS THE NORTHEAST PORTION
OF THE REGION WITH ISOLATED LOCATIONS RECEIVING OVER FOUR INCHES
OF RAINFALL. THIS TROUGH HAS LIFTED TO THE NORTHEAST WHILE AT THE
SURFACE, A WEAK BOUNDARY IS LOCATED JUST OFF THE SOUTHEAST COAST.
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE BEING GENERATED
ALONG THE BOUNDARY. ANOTHER WEAKER SHORT WAVE TROUGH IS LOCATED
OVER THE CENTRAL GULF OF MEXICO WHICH IS SOMEWHAT EVIDENT ON WATER
VAPOR IMAGERY. THE GFS, NAM AND ECMWF ALL DEPICT THIS FEATURE BUT
THE NAM HAS A MORE PRONOUNCED TROUGH AND THUS YIELDS THE HIGHEST
POPS. MUCH DRIER AIR ABOVE 10-15K FEET IS CURRENTLY MOVING INTO
THE REGION BEHIND THE EXITING TROUGH. WHILE THERE WILL BE SOME
INCREASE IN MOISTURE WITH THE SECONDARY TROUGH, IT WOULD APPEAR
THE NAM IS SUFFERING ONCE AGAIN FROM MESOSCALE BIAS. THE TROUGH
AXIS WILL CONTINUE THE SOUTHWEST STEERING FLOW ACROSS SOUTH
FLORIDA SO ANYTHING THAT DEVELOPS OVER THE INTERIOR WILL MOVE
AGAIN TOWARDS THE EAST COAST METRO AREA. THE RAPID REFRESH WHICH
PERFORMED VERY WELL WITH YESTERDAY`S CONVECTION AND ITS CURRENT
RUN GOES OUT THROUGH 18Z, SHOWS SOME DEVELOPMENT BEGINNING AROUND
17Z BUT DOES NOT GET TOO AGGRESSIVE. SO THAT BEING SAID HAVE LEANED
CLOSER TO THE MAV NUMBERS WHICH IS QUITE A BIT LESS FROM THE MET
GUIDANCE. ALL MODEL GUIDANCE NOW SHOWS THE MAIN TROUGH LIFTING TO
THE NORTHEAST THROUGH SATURDAY AS A STRONG TROUGH DEVELOPS IN THE
NORTH PACIFIC. THIS WILL ALLOW FOR THE DRIER AIR MASS TO FILTER
DOWN ACROSS THE PENINSULA ON SATURDAY INTO EARLY NEXT WEEK WITH
DEW POINTS ALSO DROPPING INTO THE 60S. SO A COUPLE MORE DAYS OF
THE HIGHER HUMIDITY AND MORE PLEASANT CONDITIONS FOR THE WEEKEND
AND AT LEAST EARLY NEXT WEEK.
MARINE...TRANQUIL WIND AND SEAS ARE EXPECTED THROUGH THE
REMAINDER OF THIS WEEK AND THEN ONLY A SLOW INCREASE IN THE SEAS
OVER THE WEEKEND AND INTO NEXT WEEK AS THE WIND VEERS TO A MORE
NORTH TO NORTHEAST DIRECTION. WIND SPEEDS ARE ANTICIPATED TO
REMAIN AT 15 KNOTS OR LESS HOWEVER AND SEAS WILL REMAIN WELL BELOW
ADVISORY CRITERIA.
FIRE WEATHER...NO PROBLEMS OR CONCERNS IN THE SHORT TERM. THERE
WILL BE SOME LOWER RELATIVE HUMIDITIES OVER THE WEEKEND BUT AT
THIS TIME IT LOOKS LIKE THEY WILL REMAIN ABOVE 35 PERCENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 74 87 72 / 50 30 30 20
FORT LAUDERDALE 86 76 87 75 / 50 30 20 20
MIAMI 88 75 88 75 / 50 30 20 20
NAPLES 87 71 86 72 / 50 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
205 PM EDT THU OCT 18 2012
.PREV DISCUSSION... /ISSUED 330 AM EDT THU OCT 18 2012/
SHORT TERM /TODAY THROUGH FRIDAY/...
NAM/GFS/ECMWF IN DECENT AGREEMENT THROUGH THE SHORT TERM...SO WENT
WITH A GENERAL BLEND FOR MOST ELEMENTS. LARGE MID LEVEL LOW SPINNING
OVER THE US/CANADA BORDER CONTINUES TO DEEPEN AND PROPAGATE
SOUTHEAST /500MB 00Z UA ANALYSIS HAD MORE HEIGHT FALLS DOWNSTREAM OF
THE LOW THAN HEIGHT RISES UPSTREAM/...AS COLD FRONT STRETCHING FROM
THE OCCLUDED SURFACE LOW SWEEPS ACROSS THE MISSISSIPPI VALLEY. THE
MAIN CONCERN FOR THE PERIOD REMAINS CONVECTION TRENDS FOR TODAY.
LINE OF SHOWERS AND THUNDERSTORMS CURRENTLY STRETCHED FROM MIDDLE
TENNESSEE THROUGH ALABAMA AT AFD TIME...WELL AHEAD OF THE COLD
FRONT...AND SHOULD REACH EXTREME NORTHWEST ZONES WITHIN THE HOUR.
INSTABILITY IS MINIMAL WITH NO SBCAPE SHOWING UP IN MESOANALYSIS...
AND MUCAPE VALUES AT BEST AROUND 250 J/KG...SO THE DRIVING FORCE
BEHIND THE CONVECTION IS SIMPLY THE SYNOPTIC SCALE LIFT...OF WHICH
THERE IS PLENTY. MOST HIRES GUIDANCE REALLY BREAKS THE SYSTEM DOWN
AS IT MOVES INTO GEORGIA...THOUGH THE HRRR DOES KEEP SOME SEMBLANCE
OF ORGANIZED CONVECTION. LIGHTNING ACTIVITY HAS DECREASED IN THE
LINE OVER THE LAST HOUR OR SO. SREF GUIDANCE IS HARD-PRESSED TO
BRING ANY CAPE INTO THE AREA UNTIL THIS AFTERNOON.
SO WITH THAT SAID...HAVE SORT OF TAKEN A COMPROMISE BETWEEN
EXTRAPOLATING WHAT IS ALREADY OUT THERE AND THE SUITE OF HIRES
GUIDANCE. BRING CATEGORICAL POPS INTO NORTHWEST GEORGIA OVER THE
NEXT FEW HOURS WITH DEFINITE THUNDER AT THE ONSET...THEN DECREASE
THUNDER WORDING AS PRECIPITATION SPREADS TOWARD THE METRO AREA BY
12Z. BROUGHT ADDITIONAL THUNDER BACK IN THIS AFTERNOON ACROSS
SOUTHERN ZONES AS INSTABILITY INCREASES WITH AFTERNOON HEATING. NO
REAL CONCERN WITH SEVERE WEATHER AS BEST SHEAR WILL REMAIN TO OUR
NORTH AND NORTHEAST TODAY...BUT CANNOT TOTALLY RULE OUT THE
POSSIBILITY OF AN ISOLATED STRONG TO POSSIBLY SEVERE THUNDERSTORM
ACROSS CENTRAL GEORGIA THIS AFTERNOON. GUSTY WINDS WILL BE THE MAIN
THREAT. OTHERWISE...FOR THE MOST PART LOOKS LIKE A QUICK SHOT OF
RAIN...WITH HIGHEST AMOUNTS NORTHWEST POSSIBLY UP TO A HALF INCH.
COLD FRONT SWEEPS THROUGH BEHIND THE AREA OF RAIN...WITH DRIER AIR
MOVING IN BEHIND IT. WHILE MASS FIELDS REMAIN VERY SIMILAR...MORE
DIFFERENCES BEGIN TO CREEP IN BETWEEN THE NAM AND GFS...WITH MET
GUIDANCE REMAINING A LITTLE MORE MOIST AND THUS A LITTLE WARMER
OVERNIGHT...WITH WARMER TEMPS ON FRIDAY AS WELL. AGAIN...LEANED
GENERALLY TOWARD A BLEND BUT LEANED SLIGHTLY ON THE COOLER SIDE. LOW
TEMPS TONIGHT IN SOME AREAS MAY FLIRT WITH THE UPPER 30S. THIS WILL
BE HEAVILY DEPENDENT ON DEWPOINTS...AND LOOKING UPSTREAM BEHIND THE
FRONT THE DEWPOINTS ARE QUITE DRY. OBVIOUSLY SOME MODIFICATION OF
THE AIRMASS CAN BE EXPECTED...BUT EITHER WAY IT LOOKS LIKE TONIGHT
WILL PROBABLY HAVE THE COLDEST TEMPS OF THE SEASON THUS FAR.
OTHER ITEM OF NOTE WILL BE WINDS IN THE MOUNTAINS ON FRIDAY. AS THE
LOW DIGS SOUTHEAST TOWARD THE GREAT LAKES TODAY AND FRIDAY...THERE
MIGHT BE ENOUGH OF A GRADIENT IN THE MOUNTAINS FRIDAY AFTERNOON
BEFORE THE SURFACE HIGH BEGINS TO BUILD IN FOR POSSIBLE WIND
ADVISORY CRITERIA. TOO EARLY AT THIS POINT BUT WILL REEVALUATE WITH
LATER FORECASTS.
TDP
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE LONG TERM LOOKS TO HAVE MUCH LESS ACTIVITY IN STORE THAN THE
SHORT TERM...AS A DRY FORECAST DOMINATED BY HIGH PRESSURE IS ON TAP.
GUIDANCE IS IN GENERAL AGREEMENT WITH A WEAK SHORTWAVE PUSHING
THROUGH THE FORECAST AREA FRIDAY NIGHT AS IT ROTATES AROUND THE
BROAD UPPER CLOSED LOW CENTERED OVER THE GREAT LAKES. HOWEVER...THIS
ENERGY SHOULD BE TOO REMOVED FROM THE MOISTURE FIELD NORTH OF THE
AREA TO TRANSLATE TO ANY PRECIP CHANCES AND THE UPPER TROUGH AXIS
SHOULD BE EAST OF THE AREA BY LATER SATURDAY...THEREFORE WILL KEEP
DRY CONDITIONS AS THE UPPER RIDGE BUILDS IN FOR NEXT WEEK. MEX
GUIDANCE TEMPS CONTINUE TO LOOK TOO COOL SO HAVE RAISED A BIT
BASED ON PREVIOUS TRENDS...KEEPING MUCH OF THE AREA NEAR
SEASONABLE VALUES TO SLIGHTLY ABOVE NORMAL FROM SUNDAY ONWARD.
BAKER
&&
.AVIATION...
18Z UPDATE...
MIXTURE OF MVFR/VFR CONDITIONS CURRENTLY WITH GRADUAL IMPROVEMENTS
TO WIDESPREAD VFR BY 20Z-00Z. CLOUD SEE LOCAL TO SCATTERED MVFR
VISIBILITIES DUE TO FOG ACROSS CENTRAL GEORGIA BETWEEN 08Z AND
14Z...BUT FOR NOW I DO NOT EXPECT THIS TO EFFECT ANY OF THE TAF
SITES AS DRIER AIR AND SUFFICIENT LOW-LEVEL WINDS SHOULD KEEP THE
MOST AREAS FOG-FREE. WINDS ALREADY SW-W OR TURNING THAT DIRECTION
AND THE TREND TOWARD W WINDS WILL CONTINUE AND SPREAD EAST THROUGH
THE PERIOD. WIND SPEEDS ARE EXPECTED IN THE 6-10KT RANGE THROUGH
00Z...DIMINISHING TO 3-6KT THROUGH 14Z BEFORE INCREASING INTO THE
8-12KT RANGE 14Z-18Z. WIND GUSTS UP TO 14-16KT POSSIBLE THIS
AFTERNOON...GENERALLY BETWEEN 18Z-22Z...WITH GUSTS 14-18KT RETURNING
AFTER 14Z FRIDAY. ISOLATED TO SCATTERED SHOWERS THIS AFTERNOON AND
EVENING SHOULD REMAIN MAINLY SOUTH OF THE TAF SITES.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM FOR TIMING OF CLOUDS LIFTING AND DIMINISHING THROUGH 00Z...
OTHERWISE HIGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 72 46 73 47 / 80 10 5 5
ATLANTA 72 51 73 47 / 40 10 0 5
BLAIRSVILLE 66 42 66 40 / 10 5 0 5
CARTERSVILLE 72 40 72 44 / 10 5 0 5
COLUMBUS 79 51 76 49 / 80 10 5 5
GAINESVILLE 69 48 71 46 / 50 5 0 5
MACON 79 47 77 46 / 60 20 5 5
ROME 73 39 71 43 / 10 5 0 5
PEACHTREE CITY 74 41 74 43 / 50 10 0 5
VIDALIA 81 61 79 53 / 50 30 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
507 PM CDT THU OCT 18 2012
.DISCUSSION...
341 PM CDT
MAIN FORECAST CONCERNS CONTINUE WITH SHOWERS/POSSIBLE THUNDER THIS
AFTERNOON...AND SHOWERS TO PERSIST THROUGH FRIDAY.
LATEST WATER VAPOR IMAGERY SHOWING LARGE CLOSED UPPER LEVEL SYSTEM
OVER THE MIDWEST THIS AFTERNOON...WITH SEVERAL STRONG MID LEVEL
FEATURES WRAPPING AROUND THIS SYSTEM. THIS FORCING IN THE PRESENCE
OF STEEP LAPSE RATES...PER AMDAR SOUNDINGS AND RAP ANALYSIS...HAS
ALLOWED SHOWERS TO BLOSSOM ACROSS NORTHERN ILLINOIS. ISOLATED
CONVECTIVE ELEMENTS HAVE ALSO BEGUN TO DEVELOP OUT AHEAD OF THIS
MAIN PRECIP SHIELD ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA
WHERE STEEPER LAPSE RATES CURRENTLY RESIDE. EXPECT THESE
CONVECTIVE ELEMENTS TO BE THE MORE NORM THROUGH THE REMAINDER OF
THE AFTERNOON AS MAIN PRECIP SHIELD CONTINUES TO SHIFT ACROSS THE
AREA. ITS IN THESE CONVECTIVE ELEMENTS THAT HEAVIER SHOWERS AND
LOWER VIS COULD OCCUR...AND ALSO WHERE THE POSSIBILITY OF
THUNDER/SMALL HAIL STILL MAY OCCUR.
UPPER LEVEL LOW WILL CONTINUE TO SLOWLY MEANDER TO THE EAST
OVERNIGHT...WITH PRECIP EXPECTED TO PERSIST FOR MUCH OF THE CWA
TONIGHT. ALTHOUGH WITH MID LEVEL FEATURES/FORCING SHIFTING
EASTWARD TONIGHT...MAIN AXIS OF PRECIP SHOULD ALSO SHIFT.
NEVERTHELESS...EXPECT AT LEAST LIGHT SHOWERS OR DRIZZLE TO
CONTINUE OVERNIGHT ACROSS THE ENTIRE CWA WITH TEMPS SLOWLY
LOWERING TO AROUND 40 ACROSS NORTHERN ILLINOIS AND THE LOWER 40S
FOR THE REMAINDER OF THE CWA...AS EXPANSIVE CLOUD SHIELD REMAINS
OVERHEAD. UPPER LEVEL LOW CENTER AND COLDEST TEMPS WILL BE
OVERHEAD ON FRIDAY...WITH A SIMILAR SETUP EXPECTED ONCE AGAIN.
SHOWERS WILL BE POSSIBLE ALONG WITH A SLIGHT CHANCE FOR
THUNDERSTORMS/SMALL HAIL ONCE AGAIN IN THE AFTERNOON...WHEN LAPSE
RATES ARE ONCE AGAIN EXPECTED TO BE THE STEEPEST. TEMPS WILL
STRUGGLE TO CLIMB MUCH AS THIS CLOUD SHIELD WILL REMAIN
OVERHEAD...WITH TEMPS IN THE UPPER 40S TO AROUND 50 EXPECTED.
GUIDANCE IN FAIR AGREEMENT WITH TAKING THIS UPPER LEVEL LOW EAST
OF THE AREA BY FRIDAY NIGHT AND EARLY SATURDAY MORNING. SO
CONTINUED TREND OF LOWERING POPS THROUGH FRIDAY NIGHT BUT WITH
THESE SYSTEMS GENERALLY MOVING SLOWER THAN MODEL GUIDANCE...WASNT
TOO AGGRESSIVE WITH LOWERING THE POPS AS STRAY SHOWERS MAY
LINGERING WITH CYCLONIC FLOW STILL IN PLACE.
AS UPPER LEVEL SYSTEM CONTINUES TO DRIFT EAST ON SATURDAY...HEIGHT
RISES ON THE BACKSIDE OF THIS SYSTEM WILL SET THE STAGE FOR A
PERIOD OF UPPER LEVEL RIDGING. WHAT THIS WILL MEAN FOR THE
REMAINDER OF THE WEEKEND WILL BE CLEARING SKIES AND QUIET WEATHER
WITH AN INCREASE IN TEMPS. EXPECT WINDS TO FLOP BACK TO THE
SOUTH/SOUTHWEST LATE SATURDAY WITH WAA USHERING IN SOME WARMTH
ACROSS THE REGION. THIS WAA AND SUNNY SKIES WILL HELP TEMPS RISE
WITH FORECAST HIGHS EXPECTED TO BE IN THE UPPER 60S TO LOW 70S ON
SUNDAY. THIS WARMTH WILL CONTINUE ON MONDAY WITH A SLIGHT INCREASE
IN TEMPS...AS THEY RISE TO THE LOW TO MID 70S. ALTHOUGH WITH THE
RIDGE AXIS OVERHEAD...THIS WILL BRING A SETUP FOR STEERING FLOW TO
BRING ABOUT SOME MID LEVEL ENERGY AND ACTIVE WEATHER FOR NEXT
WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* GUSTY SOUTH WINDS THROUGH EARLY THIS EVENING.
* SHRA THROUGH THIS EVENING.
* TIMING OF 1500 FT MVFR CIGS THIS EVENING.
* POTENTIAL FOR IFR CIGS OVERNIGHT INTO FRIDAY MORNING.
RC/KB
//DISCUSSION...UPDATED 18Z...
MULTIPLE CONCERNS THIS FORECAST PERIOD WITH SURFACE AND UPPER
LEVEL LOW PRESSURE DROPPING SOUTHEASTWARD OVER THE TERMINALS.
PRECIP...LATEST RADAR SHOWS SHRA BLOSSOMING OVER EASTERN IA AND
NW IL AND THESE WILL CONTINUE TO BLOSSOM AND MOVE ENE OVER THE
TERMINALS THRU EARLY EVENING. STILL CANT COMPLETELY RULE OUT SOME
SMALL HAIL IN ANY STRONGER SHRA. TONIGHT...THERE IS A LOSS OF
VERTICAL MOTION...SO ANY PRECIP SHOULD TREND TO VERY LIGHT SHRA OR
SPOTTY DZ UNTIL A POSSIBLE RAMPING UP OF SHRA ACTIVITY EARLY- MID
FRI AFTERNOON AS A MID LEVEL DISTURBANCE ROTATES INTO AREA.
CIG/VSBY...USED LOW LEVEL RH MODEL PROGS AND REGIONAL OBS TO
CONTINUE TO FAVOR MVFR CIGS MID-LATE THIS AFTERNOON...THOUGH
TIMING IS A BIT UNCERTAIN ESPECIALLY FOR EASTERN TERMINALS. WITH
COLD LOW PRESSURE OVERHEAD TONIGHT...CIGS EXPECTED TO LOWER FROM
MVFR TO POTENTIALLY IFR. IF IFR OCCURS...PER MODEL SOUNDINGS...IT
IS LIKELY TO CONTINUE UNTIL LATE MORNING FRIDAY...WITH GRADUAL
IMPROVEMENT THEREAFTER. VSBY MAY DROP TO MVFR IN SHRA ACTIVITY
LATE THIS AFTERNOON...SO WILL NEED TO MONITOR FOR NEXT UPDATE.
MVFR VSBY IS EXPECTED TO OCCUR WITH MORE STAGNANT CONDITIONS
OVERNIGHT INTO FRI MORNING.
WINDS...SOUTH-SOUTHWEST WINDS WILL REMAIN GUSTY...WITH SOME GUSTS
AT OR A BIT ABOVE 25 KT STILL POSSIBLE THROUGH LATE
AFTERNOON/EARLY EVE. GUSTS WILL REMAIN IN 20 KT RANGE THROUGH THE
EVENING AS WINDS TURN MORE SOUTHERLY. THEN WITH LOW PRESSURE
MOVING OVERHEAD...WINDS WILL BECOME MUCH LIGHTER AND TURN FROM
SOUTHWESTERLY OVERNIGHT INTO EARLY FRIDAY TO WESTERLY OR
NORTHWESTERLY BY LATE MORNING OR EARLY AFTERNOON ON FRIDAY.
RC
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION AND WIND GUST TRENDS.
* MEDIUM CONFIDENCE IN CIGS LOWERING TO AROUND 1500 FT THIS
EVENING AND TIMING OF LOWERING...WITH LOW-MEDIUM CONFIDENCE IN
CIGS LOWERING TO IFR OVERNIGHT.
* MEDIUM-HIGH CONFIDENCE IN SHRA TRENDS THROUGH THIS EVENING.
* MEDIUM CONFIDENCE IN VSBY TRENDS...WITH PRIMARILY VFR VIS
EXPECTED IN THE SHRA.
RC/KJB
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT...RAIN SHOWERS LIKELY. MVFR CIGS/VIS POSSIBLE.
* SATURDAY AND SUNDAY...VFR. WX NIL.
* MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA/SHRA.
KREIN/RC
&&
.MARINE...
253 PM CDT
A LARGE UPPER LEVEL LOW WILL CONTINUE TO SPIN OVER OVER SOUTHERN
WISCONSIN AND SOUTHERN LAKE MICHIGAN TONIGHT AND FRIDAY BEFORE
GRADUALLY SHIFTING OFF TO THE EAST INTO SATURDAY. ONE AREA OF LOW
PRESSURE CONTINUES TO SPIN OVER THE ARROWHEAD OF MINNESOTA WITH A
SECONDARY CIRCULATION OVER WEST CENTRAL WISCONSIN. THE TWO LOWS WILL
MERGE AND WEAKEN TONIGHT AND THEN MOVE EASTWARD ACROSS SOUTHERN LAKE
MICHIGAN FRIDAY AND FRIDAY NIGHT. IN THE MEANTIME...THE PRESSURE
GRADIENT REMAINS STRONG LEADING TO 30 KT SOUTH TO SOUTHWEST WINDS
ACROSS THE LAKE...WITH SOME 35 KT GALES OCCURRING AT TIMES LATE THIS
AFTERNOON AND POSSIBLY EARLY THIS EVENING. SPEEDS LOOK TO REMAIN
STEADY THROUGH THE EVENING BUT THEN BEGIN TO SLOWLY DIMINISH AS THE
LOW BROADENS AND WEAKENS RESULTING IN A WEAKER PRESSURE GRADIENT.
THE DOWNWARD TREND SHOULD CONTINUE FRIDAY WITH WIND DIRECTION
BECOMING MORE COMPLEX AS THE LOW CROSSES THE SOUTHERN PART OF THE
LAKE. SOUTHWEST WINDS WILL OCCUR TO THE SOUTH OF THE LOW WHILE WINDS
TURN SOUTHEAST...THEN EAST...THEN NORTHEAST NORTH OF THE LOW ACROSS
THE NORTHERN HALF TO TWO-THIRDS OF THE LAKE FRIDAY. ONCE THE LOW
SHIFTS EAST FRIDAY EVENING NORTH TO NORTHWEST WINDS WILL TAKE OVER
WITH SOME MODEST INCREASE IN SPEEDS LIKELY AS THE PRESSURE GRADIENT
RECOVERS BUT THE LOW ITSELF WILL REMAIN IN A WEAKENED STATE. IN
ADDITION...WITH THE UPPER LOW PRESENT AND COLDER AIR ACROSS THE
LAKE...THERE WILL BE A GOOD CHANCE FOR WATERSPOUTS THROUGH
FRIDAY...WITH A FEW THUNDERSTORMS POSSIBLE AS WELL.
THE NORTHWEST WINDS WILL CONTINUE INTO INTO SATURDAY BEFORE TURNING
WESTERLY THEN SOUTHWESTERLY SATURDAY EVENING AS A RIDGE OF HIGH
PRESSURE BUILDS FROM SOUTHERN LAKE MICHIGAN INTO WESTERN WISCONSIN.
THE RIDGE SHIFTS EAST MONDAY ALLOWING WINDS TO TURN SOUTHEASTERLY AS
LOW PRESSURE SPREADS ACROSS THE CENTRAL AND NORTHERN PLAINS FOR THE
MIDDLE PART OF THE WEEK. SOUTH TO SOUTHEAST WINDS WILL LIKELY
INCREASE AS THE PRESSURE GRADIENT STRENGTHENS AS THE LOW TRACKS
NORTHEAST ACROSS THE UPPER MISSISSIPPI RIVER VALLEY AND LAKE
SUPERIOR. BEYOND THAT A FRONTAL BOUNDARY SHOULD CROSS THE LAKE AND
BRING A RETURN TO NORTHERLY WINDS FOR LATE WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 5 AM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
344 PM CDT THU OCT 18 2012
.DISCUSSION...
341 PM CDT
MAIN FORECAST CONCERNS CONTINUE WITH SHOWERS/POSSIBLE THUNDER THIS
AFTERNOON...AND SHOWERS TO PERSIST THROUGH FRIDAY.
LATEST WATER VAPOR IMAGERY SHOWING LARGE CLOSED UPPER LEVEL SYSTEM
OVER THE MIDWEST THIS AFTERNOON...WITH SEVERAL STRONG MID LEVEL
FEATURES WRAPPING AROUND THIS SYSTEM. THIS FORCING IN THE PRESENCE
OF STEEP LAPSE RATES...PER AMDAR SOUNDINGS AND RAP ANALYSIS...HAS
ALLOWED SHOWERS TO BLOSSOM ACROSS NORTHERN ILLINOIS. ISOLATED
CONVECTIVE ELEMENTS HAVE ALSO BEGUN TO DEVELOP OUT AHEAD OF THIS
MAIN PRECIP SHIELD ACROSS NORTHEAST ILLINOIS AND NORTHWEST INDIANA
WHERE STEEPER LAPSE RATES CURRENTLY RESIDE. EXPECT THESE
CONVECTIVE ELEMENTS TO BE THE MORE NORM THROUGH THE REMAINDER OF
THE AFTERNOON AS MAIN PRECIP SHIELD CONTINUES TO SHIFT ACROSS THE
AREA. ITS IN THESE CONVECTIVE ELEMENTS THAT HEAVIER SHOWERS AND
LOWER VIS COULD OCCUR...AND ALSO WHERE THE POSSIBILITY OF
THUNDER/SMALL HAIL STILL MAY OCCUR.
UPPER LEVEL LOW WILL CONTINUE TO SLOWLY MEANDER TO THE EAST
OVERNIGHT...WITH PRECIP EXPECTED TO PERSIST FOR MUCH OF THE CWA
TONIGHT. ALTHOUGH WITH MID LEVEL FEATURES/FORCING SHIFTING
EASTWARD TONIGHT...MAIN AXIS OF PRECIP SHOULD ALSO SHIFT.
NEVERTHELESS...EXPECT AT LEAST LIGHT SHOWERS OR DRIZZLE TO
CONTINUE OVERNIGHT ACROSS THE ENTIRE CWA WITH TEMPS SLOWLY
LOWERING TO AROUND 40 ACROSS NORTHERN ILLINOIS AND THE LOWER 40S
FOR THE REMAINDER OF THE CWA...AS EXPANSIVE CLOUD SHIELD REMAINS
OVERHEAD. UPPER LEVEL LOW CENTER AND COLDEST TEMPS WILL BE
OVERHEAD ON FRIDAY...WITH A SIMILAR SETUP EXPECTED ONCE AGAIN.
SHOWERS WILL BE POSSIBLE ALONG WITH A SLIGHT CHANCE FOR
THUNDERSTORMS/SMALL HAIL ONCE AGAIN IN THE AFTERNOON...WHEN LAPSE
RATES ARE ONCE AGAIN EXPECTED TO BE THE STEEPEST. TEMPS WILL
STRUGGLE TO CLIMB MUCH AS THIS CLOUD SHIELD WILL REMAIN
OVERHEAD...WITH TEMPS IN THE UPPER 40S TO AROUND 50 EXPECTED.
GUIDANCE IN FAIR AGREEMENT WITH TAKING THIS UPPER LEVEL LOW EAST
OF THE AREA BY FRIDAY NIGHT AND EARLY SATURDAY MORNING. SO
CONTINUED TREND OF LOWERING POPS THROUGH FRIDAY NIGHT BUT WITH
THESE SYSTEMS GENERALLY MOVING SLOWER THAN MODEL GUIDANCE...WASNT
TOO AGGRESSIVE WITH LOWERING THE POPS AS STRAY SHOWERS MAY
LINGERING WITH CYCLONIC FLOW STILL IN PLACE.
AS UPPER LEVEL SYSTEM CONTINUES TO DRIFT EAST ON SATURDAY...HEIGHT
RISES ON THE BACKSIDE OF THIS SYSTEM WILL SET THE STAGE FOR A
PERIOD OF UPPER LEVEL RIDGING. WHAT THIS WILL MEAN FOR THE
REMAINDER OF THE WEEKEND WILL BE CLEARING SKIES AND QUIET WEATHER
WITH AN INCREASE IN TEMPS. EXPECT WINDS TO FLOP BACK TO THE
SOUTH/SOUTHWEST LATE SATURDAY WITH WAA USHERING IN SOME WARMTH
ACROSS THE REGION. THIS WAA AND SUNNY SKIES WILL HELP TEMPS RISE
WITH FORECAST HIGHS EXPECTED TO BE IN THE UPPER 60S TO LOW 70S ON
SUNDAY. THIS WARMTH WILL CONTINUE ON MONDAY WITH A SLIGHT INCREASE
IN TEMPS...AS THEY RISE TO THE LOW TO MID 70S. ALTHOUGH WITH THE
RIDGE AXIS OVERHEAD...THIS WILL BRING A SETUP FOR STEERING FLOW TO
BRING ABOUT SOME MID LEVEL ENERGY AND ACTIVE WEATHER FOR NEXT
WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WINDS 200-230 DEG WITH GUSTS UP TO 25 KT+...WITH ONLY SPORADIC
GUSTS TO 30 KT...GRADUALLY TURNING TO 190-220 DEG LATER THIS
AFTERNOON AND 170-200 DEG THIS EVENING...WITH GUSTS TO AROUND 20
KT THROUGH ABOUT 06Z.
* SHRA THROUGH THIS EVENING.
* TIMING OF 1500 FT MVFR CIGS THIS EVENING.
* POTENTIAL FOR IFR CIGS OVERNIGHT INTO FRIDAY MORNING.
RC
//DISCUSSION...UPDATED 18Z...
MULTIPLE CONCERNS THIS FORECAST PERIOD WITH SURFACE AND UPPER
LEVEL LOW PRESSURE DROPPING SOUTHEASTWARD OVER THE TERMINALS.
PRECIP...LATEST RADAR SHOWS SHRA BLOSSOMING OVER EASTERN IA AND
NW IL AND THESE WILL CONTINUE TO BLOSSOM AND MOVE ENE OVER THE
TERMINALS THRU EARLY EVENING. STILL CANT COMPLETELY RULE OUT SOME
SMALL HAIL IN ANY STRONGER SHRA. TONIGHT...THERE IS A LOSS OF
VERTICAL MOTION...SO ANY PRECIP SHOULD TREND TO VERY LIGHT SHRA OR
SPOTTY DZ UNTIL A POSSIBLE RAMPING UP OF SHRA ACTIVITY EARLY- MID
FRI AFTERNOON AS A MID LEVEL DISTURBANCE ROTATES INTO AREA.
CIG/VSBY...USED LOW LEVEL RH MODEL PROGS AND REGIONAL OBS TO
CONTINUE TO FAVOR MVFR CIGS MID-LATE THIS AFTERNOON...THOUGH
TIMING IS A BIT UNCERTAIN ESPECIALLY FOR EASTERN TERMINALS. WITH
COLD LOW PRESSURE OVERHEAD TONIGHT...CIGS EXPECTED TO LOWER FROM
MVFR TO POTENTIALLY IFR. IF IFR OCCURS...PER MODEL SOUNDINGS...IT
IS LIKELY TO CONTINUE UNTIL LATE MORNING FRIDAY...WITH GRADUAL
IMPROVEMENT THEREAFTER. VSBY MAY DROP TO MVFR IN SHRA ACTIVITY
LATE THIS AFTERNOON...SO WILL NEED TO MONITOR FOR NEXT UPDATE.
MVFR VSBY IS EXPECTED TO OCCUR WITH MORE STAGNANT CONDITIONS
OVERNIGHT INTO FRI MORNING.
WINDS...SOUTH-SOUTHWEST WINDS WILL REMAIN GUSTY...WITH SOME GUSTS
AT OR A BIT ABOVE 25 KT STILL POSSIBLE THROUGH LATE
AFTERNOON/EARLY EVE. GUSTS WILL REMAIN IN 20 KT RANGE THROUGH THE
EVENING AS WINDS TURN MORE SOUTHERLY. THEN WITH LOW PRESSURE
MOVING OVERHEAD...WINDS WILL BECOME MUCH LIGHTER AND TURN FROM
SOUTHWESTERLY OVERNIGHT INTO EARLY FRIDAY TO WESTERLY OR
NORTHWESTERLY BY LATE MORNING OR EARLY AFTERNOON ON FRIDAY.
RC
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION AND WIND GUST TRENDS.
* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR AROUND 2500 FT MID-LATE
AFTERNOON...MEDIUM CONFIDENCE IN EXACT TIMING AND CIG BASE
HEIGHT.
* MEDIUM CONFIDENCE IN CIGS LOWERING TO AROUND 1500 FT THIS
EVENING AND TIMING OF LOWERING...WITH LOW-MEDIUM CONFIDENCE IN
CIGS LOWERING TO IFR OVERNIGHT.
* MEDIUM-HIGH CONFIDENCE IN SHRA TRENDS THROUGH THIS EVENING.
* MEDIUM CONFIDENCE IN VSBY TRENDS...WITH MVFR VSBY POSSIBLE IN
SHRA THIS AFTERNOON.
* LOW CONFIDENCE IN SMALL HAIL OCCURRING AT THE TERMINALS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT...RAIN SHOWERS LIKELY. MVFR CIGS/VIS POSSIBLE.
* SATURDAY AND SUNDAY...VFR. WX NIL.
* MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA/SHRA.
KREIN/RC
&&
.MARINE...
253 PM CDT
A LARGE UPPER LEVEL LOW WILL CONTINUE TO SPIN OVER OVER SOUTHERN
WISCONSIN AND SOUTHERN LAKE MICHIGAN TONIGHT AND FRIDAY BEFORE
GRADUALLY SHIFTING OFF TO THE EAST INTO SATURDAY. ONE AREA OF LOW
PRESSURE CONTINUES TO SPIN OVER THE ARROWHEAD OF MINNESOTA WITH A
SECONDARY CIRCULATION OVER WEST CENTRAL WISCONSIN. THE TWO LOWS WILL
MERGE AND WEAKEN TONIGHT AND THEN MOVE EASTWARD ACROSS SOUTHERN LAKE
MICHIGAN FRIDAY AND FRIDAY NIGHT. IN THE MEANTIME...THE PRESSURE
GRADIENT REMAINS STRONG LEADING TO 30 KT SOUTH TO SOUTHWEST WINDS
ACROSS THE LAKE...WITH SOME 35 KT GALES OCCURRING AT TIMES LATE THIS
AFTERNOON AND POSSIBLY EARLY THIS EVENING. SPEEDS LOOK TO REMAIN
STEADY THROUGH THE EVENING BUT THEN BEGIN TO SLOWLY DIMINISH AS THE
LOW BROADENS AND WEAKENS RESULTING IN A WEAKER PRESSURE GRADIENT.
THE DOWNWARD TREND SHOULD CONTINUE FRIDAY WITH WIND DIRECTION
BECOMING MORE COMPLEX AS THE LOW CROSSES THE SOUTHERN PART OF THE
LAKE. SOUTHWEST WINDS WILL OCCUR TO THE SOUTH OF THE LOW WHILE WINDS
TURN SOUTHEAST...THEN EAST...THEN NORTHEAST NORTH OF THE LOW ACROSS
THE NORTHERN HALF TO TWO-THIRDS OF THE LAKE FRIDAY. ONCE THE LOW
SHIFTS EAST FRIDAY EVENING NORTH TO NORTHWEST WINDS WILL TAKE OVER
WITH SOME MODEST INCREASE IN SPEEDS LIKELY AS THE PRESSURE GRADIENT
RECOVERS BUT THE LOW ITSELF WILL REMAIN IN A WEAKENED STATE. IN
ADDITION...WITH THE UPPER LOW PRESENT AND COLDER AIR ACROSS THE
LAKE...THERE WILL BE A GOOD CHANCE FOR WATERSPOUTS THROUGH
FRIDAY...WITH A FEW THUNDERSTORMS POSSIBLE AS WELL.
THE NORTHWEST WINDS WILL CONTINUE INTO INTO SATURDAY BEFORE TURNING
WESTERLY THEN SOUTHWESTERLY SATURDAY EVENING AS A RIDGE OF HIGH
PRESSURE BUILDS FROM SOUTHERN LAKE MICHIGAN INTO WESTERN WISCONSIN.
THE RIDGE SHIFTS EAST MONDAY ALLOWING WINDS TO TURN SOUTHEASTERLY AS
LOW PRESSURE SPREADS ACROSS THE CENTRAL AND NORTHERN PLAINS FOR THE
MIDDLE PART OF THE WEEK. SOUTH TO SOUTHEAST WINDS WILL LIKELY
INCREASE AS THE PRESSURE GRADIENT STRENGTHENS AS THE LOW TRACKS
NORTHEAST ACROSS THE UPPER MISSISSIPPI RIVER VALLEY AND LAKE
SUPERIOR. BEYOND THAT A FRONTAL BOUNDARY SHOULD CROSS THE LAKE AND
BRING A RETURN TO NORTHERLY WINDS FOR LATE WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 5 AM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
432 PM CDT THU OCT 18 2012
.UPDATE...
UPDATED FOR 100 PERCENT COVERAGE OF RAINFALL IN THE PERSISTENT
BAND OF RAIN OVER THE CWA THE REMAINDER OF THE AFTERNOON. ALSO
INCREASED POPS SOMEWHAT OVER THE SOUTH HALF THIS EVENING DUE TO
WIDESPREAD COVERAGE. RAINFALL AMOUNTS FROM TODAY AND EARLY EVENING
SHOULD RANGE FROM 0.1 TO 0.2 IN MOST LOCATIONS.
ERVIN
&&
.PREV DISCUSSION... /ISSUED 352 PM CDT THU OCT 18 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN 850MB LOW ALONG THE MN/WI BORDER NORTHEAST
OF KMSP. THE 850MB COLD FRONT RAN FROM THE LOW INTO LOWER MICHIGAN
AND THEN SOUTH TO SOUTHEAST ARKANSAS AND THEN INTO CENTRAL TEXAS.
SEVERAL TROFS RAN BEHIND THE COLD FRONT FROM WI/IL BACK THROUGH
IOWA AND NEBRASKA. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON
SHOW EXTENSIVE WRAP AROUND CLOUDS ACROSS THE AREA WITH LIGHT RAIN
AND DRIZZLE ACROSS THE AREA.
18Z SFC ANALYSIS PLACES THE SFC LOW NEAR KMSP WITH AN OCCLUDED
FRONT NORTHEAST TO ANOTHER SFC LOW OVER WESTERN LAKE SUPERIOR.
NUMEROUS WEAK TROFS RAN FROM WI/IL BACK THROUGH IOWA AND INTO
NEBRASKA. DEW POINTS WERE MAINLY IN THE 30S AND 40S ACROSS THE
MIDWEST.
SHORT TERM...TONIGHT AND FRIDAY...
ISENTROPIC UPGLIDE WILL CONTINUE ACROSS THE AREA LATE THIS
AFTERNOON RESULTING IN A LIGHT RAIN. HOWEVER...DOWNGLIDE WAS
OCCURRING ACROSS NORTHERN AND EXTREME NORTHEAST IOWA RESULTING IN
DRY CONDITIONS. TRENDS FROM THE RAP INDICATE THIS DOWNGLIDE WILL
MOVE INTO THE NORTHWEST TO NORTHERN CWFA EARLY THIS EVENING
BRIEFLY ENDING THE RAIN. THE MORE SUBSTANTIAL RAIN WILL PUSH TO
THE SOUTHERN THIRD TO 40 PERCENT OF THE CWFA.
BY LATE EVENING AND CONTINUING OVERNIGHT WEAK UPGLIDE WILL AGAIN
MOVE INTO THE NORTHERN CWFA WHILE THE MORE SUBSTANTIAL RAIN
CONTINUES TO SINK SOUTH. THUS LIGHT RAIN/DRIZZLE WILL AGAIN
DEVELOP ACROSS THE NORTHERN CWFA. AFTER MIDNIGHT WINDS ACROSS THE
NORTHERN PARTS OF THE CWFA DROP OFF SUGGESTING SOME PATCHY FOG MAY
DEVELOP PRIOR TO SUNRISE.
ON FRIDAY SPOTTY LIGHT RAIN/DRIZZLE WILL CONTINUE EARLY IN THE
MORNING WITH SOME PATCHY FOG POSSIBLE ACROSS THE NORTH. ISENTROPIC
UPGLIDE AGAIN BECOMES RE-ESTABLISHED BY LATE MORNING AND THROUGH
THE AFTERNOON. THUS...LIGHT RAIN IN CENTRAL IOWA WILL AGAIN ADVECT
INTO THE WESTERN CWFA AND CONTINUE MOVING EAST THROUGH THE
AFTERNOON HOURS. RIGHT NOW MAX TEMPERATURES FOR FRIDAY ARE IN THE
UPPER 40S TO LOWER 50S. HOWEVER...THESE MAY STILL BE TOO WARM AND
ACTUAL TEMPERATURES COULD BE SIMILAR TO THURSDAY. 08
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
UPPER LOW WILL GRADUALLY RELINQUISH CONTROL OF OUR WEATHER FRIDAY
NIGHT INTO SATURDAY AS IT CONTINUES TO PUSHLY SLOWLY EAST ACROSS
THE GREAT LAKES REGION. AREAS OF LIGHT RAIN AND DRIZZLE LOOK TO
SHUT DOWN FRIDAY EVENING WITH SUBSIDENCE BUILDING FOR OVERNIGHT.
DESPITE THE SUBSIDENCE HAVE REMAINED MORE ON PESSIMISTIC SIDE ON
SKY COVER AND CLEARING TRENDS FRIDAY NIGHT INTO SATURDAY...GIVEN
ABUNDANT LOW LEVEL MOISTURE (AIDED BY PAST FEW DAYS OF RAIN)
BENEATH INVERSION... LOWER SUN ANGLE... AND EXTENSIVE CLOUD SHIELD
AROUND UPPER LOW DEPICTED WELL BY THE NAM MODEL WHICH IS MOST
AGGRESSIVE WITH MAINTAINING CLOUDS. AS RESULT... CONTINUE TO BE
NEAR WARM SIDE OF GUIDANCE ON LOWS FRIDAY NIGHT AND NEAR BLEND OR
COOL SIDE OF GUIDANCE FOR HIGHS ON SATURDAY.
PATTERN ALOFT SET TO TRANSITION TO SOUTHWEST FLOW OVER THE REGION
BY LATE IN THE WEEKEND... WITH THE MEDIUM RANGE MODELS GENERALLY
AGREEING ON MAINTAINING SOUTHWEST FLOW ALOFT THROUGH MUCH OF NEXT
WEEK. THIS REGIME FAVORS ABOVE NORMAL TEMPS ALONG WITH BOUTS OF
UNSETTLED WEATHER. THE CHALLENGE LIES IN THE DETAILS OF THE
FORECAST AS THE MODELS DIVERGE ON ENERGY EJECTING FROM WESTERN
TROUGH... ESPECIALLY BY TUESDAY AND CONTINUING INTO THURSDAY... WHICH
HAS IMPACT ON MOVEMENT OF FRONTAL ZONE AND SUBSEQUENT TEMPERATURE
FORECAST. GIVEN THE UNCERTAINTY... STAYED LARGELY WITH MODEL CONSENSUS
ON TEMPS/POPS FOR MONDAY THROUGH THURSDAY. DPROG/DT OF BOTH ECMWF
AND GFS SHOW CONTINUED SLOWING AND FURTHER NORTHWEST TREND WITH FRONTAL
ZONE IN GENERAL BY TUESDAY INTO THURSDAY. IF TRENDS PERSIST WOULD
EXPECT DECREASE IN RAIN CHANCES AND FURTHER WARMING ON TEMPS TO MUCH
ABOVE NORMAL FOR SOME OR MOST OF THIS PERIOD TUESDAY INTO THURSDAY.
TRANSITION TO MUCH COLDER REGIME IS STILL DEPICTED BY BOTH ECMWF AND
GFS BEYOND THE SCOPE OF CURRENT EXTENDED. MAIN CHALLENGE APPEARS TO
BE JUST EXACTLY WHEN THIS TRANSITION OCCURS. 05
AVIATION... /ISSUED 1244 PM CDT THU OCT 18 2012/
MVFR CONDITIONS WITH -RA WILL DETERIORATE TO IFR CONDITIONS AFT
00Z/19 AS THE UPPER LOW ROTATES SOUTHEAST INTO NORTHERN ILLINOIS.
THE -RA WILL END FOR SEVERAL HOURS BEFORE DZ DVLPS AFT SUNSET. THE
POTENTIAL DOES EXIST FOR INCURSIONS OF LIFR PRIOR TO SUNRISE
FRIDAY. AFT SUNRISE FRIDAY THERE WILL BE A SLOW IMPROVEMENT TO
MVFR CONDITIONS. 08
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
352 PM CDT THU OCT 18 2012
.SYNOPSIS...
12Z UA ANALYSIS HAS AN 850MB LOW ALONG THE MN/WI BORDER NORTHEAST
OF KMSP. THE 850MB COLD FRONT RAN FROM THE LOW INTO LOWER MICHIGAN
AND THEN SOUTH TO SOUTHEAST ARKANSAS AND THEN INTO CENTRAL TEXAS.
SEVERAL TROFS RAN BEHIND THE COLD FRONT FROM WI/IL BACK THROUGH
IOWA AND NEBRASKA. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON
SHOW EXTENSIVE WRAP AROUND CLOUDS ACROSS THE AREA WITH LIGHT RAIN
AND DRIZZLE ACROSS THE AREA.
18Z SFC ANALYSIS PLACES THE SFC LOW NEAR KMSP WITH AN OCCLUDED
FRONT NORTHEAST TO ANOTHER SFC LOW OVER WESTERN LAKE SUPERIOR.
NUMEROUS WEAK TROFS RAN FROM WI/IL BACK THROUGH IOWA AND INTO
NEBRASKA. DEW POINTS WERE MAINLY IN THE 30S AND 40S ACROSS THE
MIDWEST.
&&
.SHORT TERM...TONIGHT AND FRIDAY...
ISENTROPIC UPGLIDE WILL CONTINUE ACROSS THE AREA LATE THIS
AFTERNOON RESULTING IN A LIGHT RAIN. HOWEVER...DOWNGLIDE WAS
OCCURRING ACROSS NORTHERN AND EXTREME NORTHEAST IOWA RESULTING IN
DRY CONDITIONS. TRENDS FROM THE RAP INDICATE THIS DOWNGLIDE WILL
MOVE INTO THE NORTHWEST TO NORTHERN CWFA EARLY THIS EVENING
BRIEFLY ENDING THE RAIN. THE MORE SUBSTANTIAL RAIN WILL PUSH TO
THE SOUTHERN THIRD TO 40 PERCENT OF THE CWFA.
BY LATE EVENING AND CONTINUING OVERNIGHT WEAK UPGLIDE WILL AGAIN
MOVE INTO THE NORTHERN CWFA WHILE THE MORE SUBSTANTIAL RAIN
CONTINUES TO SINK SOUTH. THUS LIGHT RAIN/DRIZZLE WILL AGAIN
DEVELOP ACROSS THE NORTHERN CWFA. AFTER MIDNIGHT WINDS ACROSS THE
NORTHERN PARTS OF THE CWFA DROP OFF SUGGESTING SOME PATCHY FOG MAY
DEVELOP PRIOR TO SUNRISE.
ON FRIDAY SPOTTY LIGHT RAIN/DRIZZLE WILL CONTINUE EARLY IN THE
MORNING WITH SOME PATCHY FOG POSSIBLE ACROSS THE NORTH. ISENTROPIC
UPGLIDE AGAIN BECOMES RE-ESTABLISHED BY LATE MORNING AND THROUGH
THE AFTERNOON. THUS...LIGHT RAIN IN CENTRAL IOWA WILL AGAIN ADVECT
INTO THE WESTERN CWFA AND CONTINUE MOVING EAST THROUGH THE
AFTERNOON HOURS. RIGHT NOW MAX TEMPERATURES FOR FRIDAY ARE IN THE
UPPER 40S TO LOWER 50S. HOWEVER...THESE MAY STILL BE TOO WARM AND
ACTUAL TEMPERATURES COULD BE SIMILAR TO THURSDAY. 08
.LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
UPPER LOW WILL GRADUALLY RELINQUISH CONTROL OF OUR WEATHER FRIDAY
NIGHT INTO SATURDAY AS IT CONTINUES TO PUSHLY SLOWLY EAST ACROSS
THE GREAT LAKES REGION. AREAS OF LIGHT RAIN AND DRIZZLE LOOK TO
SHUT DOWN FRIDAY EVENING WITH SUBSIDENCE BUILDING FOR OVERNIGHT.
DESPITE THE SUBSIDENCE HAVE REMAINED MORE ON PESSIMISTIC SIDE ON
SKY COVER AND CLEARING TRENDS FRIDAY NIGHT INTO SATURDAY...GIVEN
ABUNDANT LOW LEVEL MOISTURE (AIDED BY PAST FEW DAYS OF RAIN)
BENEATH INVERSION... LOWER SUN ANGLE... AND EXTENSIVE CLOUD SHIELD
AROUND UPPER LOW DEPICTED WELL BY THE NAM MODEL WHICH IS MOST
AGGRESSIVE WITH MAINTAINING CLOUDS. AS RESULT... CONTINUE TO BE
NEAR WARM SIDE OF GUIDANCE ON LOWS FRIDAY NIGHT AND NEAR BLEND OR
COOL SIDE OF GUIDANCE FOR HIGHS ON SATURDAY.
PATTERN ALOFT SET TO TRANSITION TO SOUTHWEST FLOW OVER THE REGION
BY LATE IN THE WEEKEND... WITH THE MEDIUM RANGE MODELS GENERALLY
AGREEING ON MAINTAINING SOUTHWEST FLOW ALOFT THROUGH MUCH OF NEXT
WEEK. THIS REGIME FAVORS ABOVE NORMAL TEMPS ALONG WITH BOUTS OF
UNSETTLED WEATHER. THE CHALLENGE LIES IN THE DETAILS OF THE
FORECAST AS THE MODELS DIVERGE ON ENERGY EJECTING FROM WESTERN
TROUGH... ESPECIALLY BY TUESDAY AND CONTINUING INTO THURSDAY... WHICH
HAS IMPACT ON MOVEMENT OF FRONTAL ZONE AND SUBSEQUENT TEMPERATURE
FORECAST. GIVEN THE UNCERTAINTY... STAYED LARGELY WITH MODEL CONSENSUS
ON TEMPS/POPS FOR MONDAY THROUGH THURSDAY. DPROG/DT OF BOTH ECMWF
AND GFS SHOW CONTINUED SLOWING AND FURTHER NORTHWEST TREND WITH FRONTAL
ZONE IN GENERAL BY TUESDAY INTO THURSDAY. IF TRENDS PERSIST WOULD
EXPECT DECREASE IN RAIN CHANCES AND FURTHER WARMING ON TEMPS TO MUCH
ABOVE NORMAL FOR SOME OR MOST OF THIS PERIOD TUESDAY INTO THURSDAY.
TRANSITION TO MUCH COLDER REGIME IS STILL DEPICTED BY BOTH ECMWF AND
GFS BEYOND THE SCOPE OF CURRENT EXTENDED. MAIN CHALLENGE APPEARS TO
BE JUST EXACTLY WHEN THIS TRANSITION OCCURS. 05
&&
.AVIATION... /ISSUED 1244 PM CDT THU OCT 18 2012/
MVFR CONDITIONS WITH -RA WILL DETERIORATE TO IFR CONDITIONS AFT
00Z/19 AS THE UPPER LOW ROTATES SOUTHEAST INTO NORTHERN ILLINOIS.
THE -RA WILL END FOR SEVERAL HOURS BEFORE DZ DVLPS AFT SUNSET. THE
POTENTIAL DOES EXIST FOR INCURSIONS OF LIFR PRIOR TO SUNRISE
FRIDAY. AFT SUNRISE FRIDAY THERE WILL BE A SLOW IMPROVEMENT TO
MVFR CONDITIONS. 08
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
08/05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1244 PM CDT THU OCT 18 2012
.UPDATE...
TRENDS FROM THE RAP WITH SOME INPUT FROM THE WRF ARE INTERESTING.
THE CURRENT PRECIPITATION BAND OVER MUCH OF IOWA IS BEING
MAINTAINED BY AN AREA OF BROAD ISENTROPIC LIFT. HOWEVER...THERE IS
AN AREA OF ISENTROPIC DOWN GLIDE OCCURRING ACROSS NORTHERN IOWA.
THE RAP TRENDS INDICATE THIS DOWN GLIDE WILL BEGIN MOVING INTO THE
NORTHWEST CWFA THIS AFTERNOON AND AFFECT NEARLY THE NORTHERN HALF
FROM LATE AFTERNOON THROUGH EARLY EVENING. AT THE SAME TIME THE
LIFT ACROSS THE SOUTHERN HALF OF THE CWFA WILL BECOME MORE NEUTRAL.
WHAT IS BEING SUGGESTED IS THE RAIN ENDING ACROSS THE NORTHERN
CWFA DURING THE AFTERNOON OR BECOMING VERY SPOTTY WITH RAIN
CONTINUING ACROSS THE SOUTH BUT DECREASING IN AREAL COVERAGE LATE
THIS AFTERNOON AND EVENING.
BY LATE EVENING AN AREA OF WEAKER ISENTROPIC LIFT BEGINS MOVING
INTO THE NORTHERN CWFA SUGGESTING POSSIBLY SOME -RA OR DZ
DEVELOPING. THE WRF PARTIALLY COMPLEMENTS WHAT THE RAP IS
SUGGESTING. AFTER MIDNIGHT THE WRF SUGGESTS THE RAIN MAY END
ACROSS A MAJORITY OF THE AREA WITH DZ DEVELOPING.
TEMPERATURES MAY PARTIALLY REBOUND ACROSS THE NORTH WITH THE RAIN
ENDING. HOWEVER...MUCH OF THE CWFA WILL REMAIN IN THE 40S FOR THE
REMAINDER OF DAYLIGHT HOURS. ACROSS THE FAR EAST/SOUTH
TEMPERATURES MAY HOLD IN THE LOW 50S. ..08..
&&
.AVIATION...
MVFR CONDITIONS WITH -RA WILL DETERIORATE TO IFR CONDITIONS AFT
00Z/19 AS THE UPPER LOW ROTATES SOUTHEAST INTO NORTHERN ILLINOIS.
THE -RA WILL END FOR SEVERAL HOURS BEFORE DZ DVLPS AFT SUNSET. THE
POTENTIAL DOES EXIST FOR INCURSIONS OF LIFR PRIOR TO SUNRISE
FRIDAY. AFT SUNRISE FRIDAY THERE WILL BE A SLOW IMPROVEMENT TO
MVFR CONDITIONS. ..08..
&&
.PREV DISCUSSION... /ISSUED 1012 AM CDT THU OCT 18 2012/
UPDATE...
RADAR TRENDS THROUGH MID MORNING SHOWS THE PRECIP IS MOVING IN
SOONER THAN EXPECTED.
EXTRAPOLATION PLACES -RA OR SHRA ACROSS NEARLY ALL THE AREA BY MID
DAY. DURING THE AFTERNOON HOURS THE CURRENT BAND OF RAIN ACROSS
CENTRAL IOWA WILL ROTATE ACROSS AREAS SOUTH OF HWY 20. THE
IMMEDIATE HWY 20 CORRIDOR SHOULD SEE MORE SHOWERS THAN CONTINUOUS
LIGHT RAIN. BY LATE AFTERNOON MORE SHOWERS ARE EXPECTED
ALONG/NORTH OF HWY 30 WITH THE MORE PERSISTENT LIGHT RAIN
CONTINUES FROM THE I-80 CORRIDOR ON SOUTH.
TEMPERATURES WILL BARELY MOVE FOR THE REMAINDER OF THE DAY WHERE
THE RAIN PERSISTS. THE EXCEPTION WILL BE THE FAR EAST/SOUTH WHERE
TEMPERATURES MAY MANAGE TO RISE INTO THE LOWER 50S BEFORE THE RAIN
BEGINS. ..08..
PREV DISCUSSION... /ISSUED 330 AM CDT THU OCT 18 2012/
SYNOPSIS...
THERE IS A STRONG SURFACE LOW OVER NORTHWEST MINNESOTA...ALONG WITH
A SECONDARY SURFACE LOW OVER NORTHEAST WISCONSIN. THE STRONG COLD
FRONT THAT SWEPT THROUGH THE FORECAST AREA WEDNESDAY AFTERNOON IS
NOW WELL EAST OF THE AREA...HAVING PUSHED INTO INDIANA AND MICHIGAN
OVERNIGHT. WE ARE LEFT WITH DEEP COLD AIR ADVECTION OVER THE AREA
WITH WEST TO SOUTHWEST WINDS IN THE 10-15KT RANGE. AN AREA OF
CONVERGENCE AT MID LEVELS AND A SHORTWAVE IN THE STRONG...CUT OFF
UPPER LEVEL LOW OVER SOUTHERN MINNESOTA HAS GENERATED AN AREA OF
SHOWERS OVER SOUTHERN MINNESOTA THIS MORNING...WITH OTHER
SURROUNDING SITES REPORTING DRIZZLE. LE
SHORT TERM...TODAY AND TONIGHT
THE STRONG CUT OFF UPPER LEVEL LOW NOW OVER SOUTHERN MINNESOTA IS
NOW FORECAST TO SLOWLY EAST SOUTHEAST TODAY AND TONIGHT...ENDING UP
OVER NORTHERN ILLINOIS BY FRIDAY MORNING. THE SURFACE LOW IS
EXPECTED TO TAKE A SIMILAR TRACK AS THE SYSTEM BECOMES MORE STACKED
WITH TIME. THIS IS GOING TO KEEP THE FORECAST AREA IN A VERY MOIST
ATMOSPHERE WITHIN WHICH IT WILL BE VERY EASY FOR WEAK SHORTWAVES TO
PRODUCE RAIN. THUS...WE ARE GOING TO GET SOME MORE MUCH NEEDED
RAINFALL TODAY...THOUGH QPF AMOUNTS WILL BE RELATIVELY LIGHT. FOR
NOW...AM TRACKING A DECENT WAVE OF CONVERGENCE AND 500MB PVA THAT
ALONG WITH SOME WRAP-AROUND ISENTROPIC LIFT WILL BRING A BAND OF
RAIN INTO THE FORECAST AREA DURING THE LATE MORNING AND EARLY
AFTERNOON HOURS. IT WILL BE DIURNALLY ENHANCED...SO IT WILL LIKELY
MUCH LARGER THAN WHAT WE ARE NOW SEEING CROSSING INTO NORTHWEST
IOWA. THAT SAID...HAVE SOME LIKELY TO CATEGORICAL POPS ACROSS THE
FORECAST AREA FOR THIS AFTERNOON AND EVENING AS THIS PARTICULAR WAVE
OF PRECIPITATION MOVES ACROSS THE AREA. UNDER ALL THE CLOUDS THIS
IS GOING TO GENERATE TODAY...HIGH TEMPERATURES ARE GOING TO BE
TRAPPED IN THE MID 40S TO LOW 50S. THIS WILL ACT TO KEEP
TEMPERATURES UP TONIGHT AS WELL. WHILE THE MAIN SHORTWAVE AND
PRECIPITATION WILL SHIFT OFF TO THE SOUTHEAST OVERNIGHT...EXPECT
THAT WE WILL STILL BE UNDER A LOT OF CLOUD COVER MOST OF THE
NIGHT. DRIZZLE MAY BE FAIRLY PREVALENT TONIGHT...BUT FOR NOW HAVE
LEFT OUT OF THE PUBLIC FORECAST AND WE CAN RE-EVALUATE WITH LATER
FORECASTS. MIN TEMPS TONIGHT...WHILE COLDER THAN THIS MORNINGS
VALUES WILL BE DOWN IN THE AROUND 40 TO 45 RANGE. LE
LONG TERM...FRIDAY THROUGH WEDNESDAY
A FINAL WAVE OF VORTICITY ROTATING AROUND THE DEPARTING UPPER LOW
WILL PASS THROUGH THE AREA DURING THE DAY FRIDAY...KEEPING AT LEAST
SCATTERED LIGHT SHOWERS GOING...ALONG WITH CONTINUED CLOUDY AND COOL
CONDITIONS. WITH GOOD MODEL AGREEMENT...HAVE INCREASED POPS TO
LIKELY OVER ALL BUT THE FAR SOUTHWEST...FOLLOWING THE TIMING OF THE
UPPER LEVEL IMPULSE. TEMPERATURES WILL STRUGGLE INTO THE UPPER 40S
NORTH TO LOWER 50S SOUTH. QPF VALUES ARE KEPT BELOW A TENTH OF AN
INCH BASED ON THE WEAK LIFT AND SOMEWHAT LIMITED MOISTURE WRAPPING
AROUND THE LARGE UPPER LOW.
FRIDAY NIGHT...HOW LONG THE CYCLONIC FLOW LINGERS OVER THE
AREA...ALONG WITH THE AMOUNT LOW LEVEL MOISTURE WILL BE CRITICAL TO
CLOUD COVER AND OVERNIGHT MINS. WILL STAY THE COURSE WITH THE
SLIGHTLY SLOWER AND CONSISTENT ECMWF THAT WOULD KEEP AT LEAST MOSTLY
CLOUDY SKIES IN PLACE...HOLDING MINS IN THE UPPER 30S TO LOWER 40S.
THERE IS SOME INDICATION THAT THERE COULD BE POCKETS OF CLEARING
ROTATING THROUGH...WHICH COULD RESULT IN MUCH COOLER TEMPERATURES AS
LOW AS THE MID 30S...ESPECIALLY ACROSS THE NORTH AND NORTHEAST...
THAT WILL NEED TO BE WATCHED FOR LATER FORECASTS.
OVER THE WEEKEND...A TRANSITORY SURFACE RIDGE WILL BE FOLLOWED BY A
SHARP WARMING TREND COMMENCING SATURDAY NIGHT THAT SHOULD PUSH HIGH
TEMPERATURES FROM THE 50S SATURDAY...INTO THE 70S SUNDAY. DEVELOPING
SOUTHERLY WINDS SHOULD LIMIT MINS SATURDAY NIGHT TO THE 50S. A
DEVELOPING SW FLOW IS SHOWN SURGING GULF MOISTURE AND STRONG WARM
ADVECTION ALOFT INTO THE AREA BY SUNDAY EVENING.
A PERSISTENT SW FLOW OF GULF MOISTURE IS THEN DEPICTED IMPINGING
ON A DEVELOPING SURFACE BOUNDARY THAT STALLS OUT OVER THE REGION IN
A SW TO NE CONFIGURATION MONDAY THROUGH WEDNESDAY. THE ECMWF AND GFS
WOULD KEEP OUR AREA FIRMLY IN THE WARM SECTOR FOR MONDAY...WHILE THE
GEM AND DGEX HAVE THE BOUNDARY SETTING UP OVERHEAD OR EVEN SOUTH OF
THE AREA. IF THE FORMER IS CORRECT...TEMPERATURES COULD BE WELL INTO
THE 70S TO POSSIBLY NEAR 80...WHILE THE LATTER SOLUTIONS COULD
RESULT IN WIDESPREAD CLOUD COVER...PRECIPITATION...AND TEMPERATURES
ONLY IN THE 50S. LATEST MODEL SOLUTIONS CONTINUE TO DIVERGE TUE INTO
WED IN THE CRITICAL LOCATION OF THIS SURFACE FRONT. OUR BLENDED
APPROACH RESULTS IN A MIDDLE OF THE ROAD FORECAST OF SEVERAL DAYS OF
AT LEAST CHANCE POPS FOR SHOWERS AND POSSIBLE THUNDERSTORMS WITH
HIGHS IN 60S AND 70S AND LOWS IN THE 50S. WITH THE GFS SHOWING PW
VALUES OVER 200 PERCENT OVER THE REGION...THERE WILL BE A POTENTIAL
FOR ANOTHER ROUND OF SOAKING RAINS SOMEWHERE IN THE AREA.
SHEETS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
309 PM EDT THU OCT 18 2012
.SYNOPSIS...
A STRONG WEATHER SYSTEM WILL BEGIN IMPACTING THE REGION LATER
TONIGHT WITH RAIN GRADUALLY OVERSPREADING THE AREA AS THE
OVERNIGHT HOURS PROGRESS. AT TIMES...RAIN MAY BECOME HEAVY AT
TIMES LATER TONIGHT AND FRIDAY MORNING AS HIGH AMOUNTS OF MOISTURE
INTERACT WITH A NORTHWARD MOVING WARM FRONT AND SURFACE LOW. RAIN
WILL LINGER ACROSS THE REGION ON FRIDAY WITH THUNDERSTORMS
BECOMING POSSIBLE FROM THE LOWER WYOMING VALLEY NORTH THROUGH THE
POCONOS AND CATSKILLS. UNSETTLED WEATHER WILL THEN CONTINUE
THROUGH THE UPCOMING WEEKEND AS THE UPPER LOW SLOWLY MOVES OVER
THE REGION.
&&
.NEAR TERM /THROUGH FRIDAY/... LATEST VIS SATELLITE IMAGERY
CONTINUES TO SHOW CLOUDS STREAMING NORTHEAST FROM THE LWR OHIO
VALLEY THIS AFTERNOON AS COLD/OCCLUDED FRONTAL BOUNDARY ADVANCES
EAST. ALOFT...WATER VAPOR IMAGERY SHOWING A DEEPLY WOUND- UP UPPER
LOW ACROSS THE UPPER MISS RVR VLY WITH RUC POTENTIAL VORTICITY
COMPOSITES INDICATING THE THE UPPER PV ANOMALY EXTENDS DOWN TO
NEAR 500 MB ACROSS THE OHIO/MISS RVR CONFLUENCE REGION. THIS LEAD
WAVE WILL CONTINUE MOVING NORTHEAST OVERNIGHT WHICH WILL
ULTIMATELY HELP PROPEL THE AFOREMENTIONED COLD/OCCLUDED FRONT EAST
INTO OUR FCST AREA. LATEST RADAR TRENDS NOW SHOWING INITIAL
FRONTAL WAVE RAIN BAND SLOWLY LIFTING NORTHEAST THROUGH EASTERN
OHIO THIS AFTERNOON WHICH WITH TIME SHOULD BEGIN ENTERING OUR
WESTERN ZONES AFTER 00Z THIS EVENING. CLOSER TO THE SFC...A STRONG
PRESSURE GRADIENT BETWEEN THIS DEEPLY WOUND-UP SYSTEM AND
DEPARTING HIGH PRESSURE OFF THE EAST COAST HAS ALLOWED FOR STRONG
SOUTHEASTERLY WINDS THIS AFTERNOON WITH LATEST OBSERVATIONS
SHOWING GUSTS AS HIGH AS 35 KTS ACROSS THE REGION.
AS HAS THE BEEN THE CONCERN IN RECENT DAYS...12Z MODEL GUIDANCE
CONTINUES TO ADVERTISE FAVORABLE CONDITIONS FOR A DECENT RAINFALL
EVENT ACROSS MUCH OF CENTRAL NY AND NE PA BEGINNING TONIGHT AS
INITAL PV ANOMALY AND SFC FRONT TRANSLATE NORTHEAST OVER THE AREA.
AHEAD OF THESE FEATURES...STRONG MOISTURE ADVECTION CHARACTERIZED
H925 V-WIND COMPONENTS ON THE ORDER OF 2-3 STANDARD DEVIATIONS ABOVE
NORMAL WILL HELP INCREASE PWAT VALUES TO WELL OVER 1 INCH ACROSS THE
EASTERN ZONES BY 12Z FRI. AS THIS OCCURS...MODELS NOW SHOWING A
SECONDARY FRONTAL WAVE AND CORRESPONDING WARM FRONT MOVING NORTH
ALONG THE OCCLUDED FRONT OVERNIGHT WHICH WILL EFFECTIVLY HELP
STALL THE MAIN OCCLUDED FRONT WITH TIME ACROSS OUR FCST AREA EARLY
FRI. BY 15Z...MODELS INDICATE THAT THE TRIPLE POINT WILL RESIDE
OVER OR REGION WITH EASTERN ZONES EFFECTIVELY BECOMING PLACED IN
MODIFYING WARM SECTOR AIR. MODELS CONTINUE TO SUGGEST THE
DEVELOPMENT OF WEAK INSTABILITY AFTER 12Z FRI AS DEWPOINTS CLIMB
INTO THE MIDDLE TO UPPER 50S...AND POSSIBLY LOWER 60S ACROSS OUR
FAR SOUTHEAST. MEANWHILE ALOFT...MODELS STILL ADVERTISING THE
ENTRANCE OF A MID-LEVEL JET BY LATE MORNING WHICH WILL INCREASE
THE VERTICAL WIND SHEAR PROFILE ACROSS THE REGION. CONSIDERING
THAT SUCH STRONG WIND FIELD WILL BE IN PLACE (0-6 KM BULK SHEAR
WELL OVER 50 KTS)...DEVELOPING CONVECTION COULD EASILY BE SHEARED
APART AS IT FIRES. THAT SAID...WITH STRONGER INSTABILITY SUGGESTED
WITH TODAY/S RUNS...HAVE ELECTED TO REINTRODUCE A THUNDER MENTION
FOR FRI FROM THE LWR WYOMING VLY NORTH THROUGH THE POCONOS AND
CATSKILLS.
WITH RESPECT TO FCST QPF AMOUNTS...HPC GUIDANCE CONTINUES TO
ADVERTISE CLOSE TO 2" ACROSS THE EASTERN POCONOS AND CATSKILLS
WHERE MOIST SOUTHEAST WINDS WILL INTERACT WITH UPSLOPE TERRAIN
INFLUENCES. FOR NOW HAVE FOLLOWED BOTH HPC AND RFC QPF GUIDANCE
WHICH KEEPS THE HIGHEST AMOUNTS ACROSS THE EASTERN HALF OF THE
CWA. BY LATE MORNING...MODELS INDICATE THAT A WELL DEVELOPED DRY
SLOT WILL BEGIN WORKING INTO OUR WESTERN ZONES WHICH SHOULD RESULT
IN RAIN COMING TO AN END FROM WEST TO EAST DURING THE LATE
MORNING/EARLY AFTERNOON HRS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
UNSETTLED WX EXPECTED TO CONTINUE RIGHT THROUGH THE WEEKEND AS
UPPER LOW CONTINUES TO PINWHEEL ACROSS THE REGION BOTH FRIDAY
NIGHT AND SATURDAY. FOR ALL INTENSIVE PURPOSES...MAIN RAIN BAND
SHOULD BE EXITING TO THE EAST BY FRIDAY EVENING AS NORTHWARD
MOVING FRONTAL WAVE FRIDAY AFTERNOON FINALLY EXITS TO THE
NORTHEAST. WITH AFOREMENTIONED DRY SLOT LINGERING...HAVE MAINTAINED
SLGT CHC TO CHC MENTION FOR POPS FRI NGT. FOR SATURDAY...UPPER
WAVE TO INCH EVER SO CLOSER TO THE REGION WITH THE NEXT ROUND OF
SHORTWAVE ENERGY EXPECTED TO LEAD TO ADDITIONAL SHWRS LATE SAT
MORNING/AFTERNOON. RIGHT NOW BEST POTENTIAL FOR REDEVELOPING SHWRS
APPEAR ACROSS THE NORTHERN ZONES WHERE COLD TEMPS ALOFT WILL
COMBINE WITH BEST FORCING FOR ASCENT FROM THE MAIN SFC LOW FCST
TO LIFT FROM THE CENTRAL LAKES INTO SOUTHERN ONTARIO.
UPPER LOW TO FINALLY BEGIN LIFTING NORTHEAST OF THE REGION SAT
NIGHT/EARLY SUN AS HEIGHTS BUILD ACROSS THE NORTHERN MISS RVR
VLY/SOUTHERN CANADIAN PRAIRIE PROVINCES. BEHIND THE FEATURE...H85
TEMPS ONLY DROP TO NEAR 0C WHICH MAY RESULT IN SCATTERED LAKE
EFFECT RAIN SHWRS JUST TO OUR NORTH IN SUSTAINED SOUTHWEST LOW-
LEVEL FLOW.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
DURING THE EXTENDED PERIOD MEDIUM RANGE MODELS ARE IN AGREEMENT
THAT THE UPPER LEVEL TROF OVER THE NORTHEAST WILL BE REPLACED BY
RISING HEIGHTS AND DEVELOPMENT OF AN UPPER LEVEL RIDGE. AT THE
SURFACE THINGS ARE A BIT MORE TRICKY WITH LOW PRES MOVING THROUGH
THE UPPER GREAT LAKES WITH POSSIBLE FROPA TUESDAY NIGHT. GENERALLY
FOLLOWED HPC GUIDANCE.
SUNDAY EVENING WILL INCLUDE SLIGHT CHC POPS FAR NRN CWA ON BACK
SIDE OF UPPER LEVEL TROF THEN DRY. DRY WEATHER IS EXPECTED
MONDAY THROUGH MUCH OF MONDAY NIGHT THEN CHC/SLIGHT CHC POPS
TUESDAY THROUGH WEDNESDAY DUE TO PASSING COLD FRONT AND NORTHWEST
FLOW BEHIND BOUNDARY. DRY WEATHER WILL RETURN WED NIGHT/THURSDAY
AS SFC HIGH BUILDS DOWN FROM CANADA. TEMPS WILL BE 5-10 DEGREES
ABOVE NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE ACROSS THE TERMINALS UNTIL LATE THIS
EVENING WHEN AN OCCLUSION WILL QUICKLY LOWER THE FLIGHT CATEGORY.
LOW MVFR CONDITIONS DUE VSBYS/CIGS IN LIGHT RAIN WILL SPREAD OVER
THE REGION BETWEEN 03Z-05Z. AT KITH/KELM/KBGM/KAVP, IFR
CONDITIONS WILL BE POSSIBLE BETWEEN 08Z-12Z DUE TO LOWER CIGS AND
POSSIBLE VSBY RESTRICTIONS IN MODERATE RAIN. THIS BOUNDARY WILL
LIFTS THROUGH THE REGION DURING THE MID MORNING THROUGH EARLY
AFTERNOON PERIOD BUT MVFR RESTRICTIONS WILL PERSIST.
GUSTY SE WINDS AT 15-25 KNOTS BECOMING 10 KNOTS OVERNIGHT THEN
SHIFTING THE NORTHWEST LATE IN THE TAF PERIOD.
OUTLOOK...
FRI NIGHT THROUGH SAT...MVFR IN PROLONGED SHWR ACTIVITY.
SUN AND MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
405 PM EDT THU OCT 18 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION LATE TONIGHT INTO EARLY FRIDAY.
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS AND SOUTHERN VIRGINIA IN
THE WAKE OF THE FRONT AND LINGER OVER THE AREA THROUGH SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 305 PM THURSDAY...
CLOUDS WILL INCREASE IN COVERAGE FROM WEST TO EAST THIS EVENING
AHEAD OF A COLD FRONT APPROACHING FROM THE WEST. AS OF THE 12Z UPPER
AIR ANALYSIS...UPPER LEVEL LOW PRESSURE WAS LOCATED OVER SRN MN/NRN
IA WITH THE TROUGH EXTENDING SOUTH INTO THE LOWER MS RIVER VALLEY.
BEST HEIGHT FALLS ARE STILL WELL TO THE NW...WITH A 140KT JET AT 250
MB OVER AR EXPECTED TO MOVE EASTWARD OVER THE APPALACHIANS LATER
TODAY. 16Z SURFACE ANALYSIS PLACES THE LOW OVER WI AND THE FRONT
EXTENDING EAST AND THEN SOUTH THROUGH THE OH AND TN VALLEYS. AS THIS
FRONT MIGRATES EASTWARD TODAY...WILL SEE INCREASING LOW-LEVEL
MOISTURE AND CLOUDS. AS FOR THE CONVECTION...THE 12Z NCEP WRF NMM
DEVELOPS A LINE OF SHOWERS OVER THE WESTERN PORTIONS OF THE AREA
BETWEEN 21Z AND 00Z...MAKING IT TO APPROX THE TRIANGLE AREA BEFORE
LIFTING NE AND DISSIPATING. THE 00Z NSSL WRF ARW SHOWS A SIMILAR
SCENARIO. GIVEN THE CURRENT SPC ANALYSES SHOWING INCREASING
LOW-LEVEL LAPSE RATES AHEAD OF THE DEVELOPING LINE OF SHOWERS AND
EFFECTIVE BULK SHEAR VALUES 45-50 KTS OVER THE MTS...CURRENTLY ABOUT
20 KTS OVER CENTRAL NC. ALSO...MUCAPE VALUES ARE AROUND 500 J/KG...
MAINLY ACROSS THE SOUTH. RUC ANALYSIS SHOWS BULK SHEAR VALUES
OVER CENTRAL NC INCREASING TO 50-60 KTS...WITH CAPE OF 500-1000
J/KG...MAINLY ACROSS THE WEST. THIS SUPPORTS THE POTENTIAL FOR
THUNDERSTORMS TO DEVELOP ACROSS THE WESTERN HALF OF THE AREA
TONIGHT...WITH AN ISOLATED STRONG TO SEVERE STORM POSSIBLE. MAIN
THREAT WOULD BE DAMAGING WINDS. SHOWERS AND ISOLATED STORMS ARE ALSO
POSSIBLE ALONG THE COASTAL PLAIN AHEAD OF THE MAIN LINE OF SHOWERS
AND STORMS THIS EVENING. HOW QUICKLY THE SHOWERS AND CLOUDS MOVE OUT
OF THE AREA WILL IMPACT THE LOW TEMPS FOR TONIGHT...BUT GENERALLY
LOOKING AT NEAR 50 DEGREES NW TO LOW 60S SE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
AS OF 240 PM THURSDAY...
FRIDAY...
LARGE UPPER LOW OVER THE UPPER MIDWEST WILL MIGRATE EAST OVER THE
GREAT LAKES ON FRIDAY. THE COLD FRONT TO SLOWLY CROSS CENTRAL NC
TONIGHT IS FORECAST TO MOVE FROM ROUGHLY US HWY 1 AT 12Z TO WELL
EAST OF I-95 BY 18Z. EARLY IN THE DAY...FORCING FOR ACCENT WILL
MAINLY BE LIMITED TO UPPER DIVERGENCE IN THE RIGHT ENTRANCE OF THE
DEPARTING 120KT UPPER JET...WITH ONLY 30M HEIGHT FALLS AND
INCREASINGLY STABLE AND DRY AIR ALOFT. ANY REDEVELOPMENT OF SHOWERS
DURING THE FIRST HALF OF THE DAY WILL BE TIED TO WEAK FRONTAL
CONVERGENCE OVER THE COASTAL PLAIN...BUT EVEN THAT IS FORECAST TO
WEAKEN AS THE FLOW BECOMES MORE UNIDIRECTIONAL AND SOUTHWESTERLY.
WITH CLEARING SKIES AND A MODEST HEIGHT GRADIENT BEHIND THE
FRONT...FORECAST SOUNDINGS SHOW BOUNDARY LAYER MIXING...GREATEST IN
THE WEST...LEADING TO SOUTHWESTERLY WIND GUSTS OF UP TO 20-25KT
DURING THE AFTERNOON. A LOW LEVEL TRAJECTORY OUT OF THE SOUTHWEST
BEHIND THE FRONT WILL NOT LEAD TO A LARGE COOL DOWN BASED ON THE
UPSTREAM AIRMASS...WITH MOST GUIDANCE SHOWING HIGHS OF 70-78
NORTHWEST TO SOUTHEAST.
FRIDAY NIGHT...
OTHER THAN THE POTENTIAL FOR MID CLOUDS PASSING THROUGH THE BASE OF
THE UPPER LEVEL LOW...WHICH WILL BEGIN TO OPEN UP BY SATURDAY
MORNING...SKIES SHOULD BE MOSTLY CLEAR. AGAIN THERE IS NO REAL
STRONG COLD ADVECTION SATURDAY NIGHT AND LOWS SHOULD SETTLE JUST
BELOW NORMAL INTO THE MID TO UPPER 40S FOR MOST AREAS.
SATURDAY THROUGH SUNDAY......
THE MEAN TROUGH AXIS IS FORECAST TO CROSS THE APPALACHIANS AS
THE UPPER LOW OPENS AND LIFTS NORTHEASTWARD ON SATURDAY. THE
COMBINATION OF UPSTREAM MOISTURE AND THE COLDEST AIR ALOFT PASSING
OVERHEAD SHOULD LEAD TO ENHANCED STRATOCU IN THE LEE OF THE
MOUNTAINS DURING THE AFTERNOON. 1000-850MB THICKNESSES HOVER IN THE
1360S DURING THE DAY WITH A WEAK DOWNSLOPE FLOW POTENTIALLY
OFFSETTING WEAK COLD ADVECTION. THUS...WILL KEEP HIGHS WITHIN A
COUPLE DEGREES OF THOSE BASED ON THICKNESSES...66-73 NORTHWEST TO
SOUTHEAST. LOWS SATURDAY NIGHT IN THE LOW TO MID 40S UNDER MOSTLY
CLEAR SKIES...ALTHOUGH FORECAST SOUNDINGS SUGGEST CONDITIONS COULD
BE FAVORABLE FOR SOME OROGRAPHIC CIRRUS. HIGH PRESSURE WILL BEGIN TO
BUILD INTO THE AREA FROM THE SOUTHWEST SUNDAY WITH MOSTLY SUNNY
SKIES AND HIGHS AROUND 70S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 250 PM THURSDAY...
OVERALL...THIS PERIOD WILL BE DOMINATED BY HIGH PRESSURE BOTH AT THE
SURFACE AND ALOFT. SURFACE HIGH PRESSURE WILL SETTLE RIGHT OVER THE
REGION...WHILE A MID LEVEL RIDGE WILL BUILD IN FROM THE GULF COAST
AREA. THIS WILL RESULT IN A PROLONGED PERIOD OF DRY CONDITIONS. AS
HEIGHTS GRADUALLY INCREASE THROUGHOUT THE PERIOD...TEMPS WILL SLOWLY
MODERATE...WITH HIGHS TRENDING TO ABOVE NORMAL. HOWEVER...WITH
FAIRLY DRY AIR IN PLACE AND MOSTLY CLEAR SKIES...OUR DIURNAL RANGE
SHOULD BE LARGE...WITH OVERNIGHT LOWS ABLE TO DROP OFF INTO THE 40S.
A BACK DOOR FRONT MAY APPROACH THE REGION LATE IN THE PERIOD...BUT
AS OF NOW MODELS SHOW LITTLE IMPACT TO THE AREA.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM THURSDAY...
24 HOUR TAF PERIOD:
CHALLENGING TAF FORECAST WITH REGARD TO TIMING OF PRECIP AHEAD OF A
COLD FRONT MOVING IN FROM THE WEST OVERNIGHT AND INTO FRIDAY. BEST
CHANCE OF RAIN BEGINNING AROUND 00Z AT KINT AND KGSO...AND CLOSER TO
03Z-05Z ELSEWHERE. STILL QUITE A BIT OF UNCERTAINTY WITH REGARD
TO COVERAGE AND INTENSITY OF PRECIP AS WELL. VISBYS COULD GO DOWN TO
MVFR/IFR WHERE PRECIP IS OCCURRING...AND MVFR/IFR CIGS AND VISBYS
WITH FOG/STRATUS CONDITIONS BEGINNING AFTERWARD. CEILINGS HAVE
ALREADY GONE TO MVFR AT KINT AND KGSO AND ASIDE FROM SOME BRIEF
SCATTERING...WILL LIKELY REMAIN MVFR THE REMAINDER OF THE AFTERNOON.
CEILINGS AT THE REMAINING TERMINALS SHOULD REMAIN LOW END VFR...
POTENTIALLY DROPPING TO HIGH END MVFR BEFORE MIDNIGHT. WINDS ARE
EXPECTED TO BE GUSTY AT ALL TERMINALS THIS AFTERNOON...MAINLY OUT OF
THE SOUTH. CIG AND VISBY RESTRICTIONS SHOULD START CLEARING UP AFTER
SUNRISE FRIDAY AS DRIER AIR MOVES IN BEHIND THE FRONT.
FRIDAY NIGHT THROUGH TUESDAY:
WITH THE EXCEPTION OF SOME LINGERING SHOWERS ALONG THE COASTAL PLAIN
FRIDAY AFTERNOON...THE PRECIP AND OVERCAST SKIES SHOULD BE OUT OF
CENTRAL NC BY 15Z AND 21Z FRIDAY...RESPECTIVELY AS THE COLD FRONT
PUSHES THROUGH THE AREA. WINDS WILL BE GUSTY BEHIND THE FRONT...
POTENTIALLY 20 KTS OR MORE AT TIMES. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND LINGER THROUGH TUESDAY...RESULTING IN VFR
CONDITIONS FOR THE REMAINDER OF THE PERIOD.
&&
.FIRE WEATHER...
A COLD FRONT WILL CROSS CENTRAL NC LATE TONIGHT AND EARLY FRIDAY.
BEHIND THE FRONT...DEWPOINTS ARE FORECAST TO MIX OUT INTO THE LOW
TO MID 30S...WHILE TEMPS WILL BE RELATIVELY WARM FOR A POST-FRONTAL
AIRMASS. THIS WILL CAUSE RH VALUES TO DROP BELOW 30 PERCENT OVER
MUCH OF THE WESTERN PIEDMONT. CONCURRENTLY...SOUTHWESTERLY WIND
GUSTS WILL LIKELY REACH THE 20-25MPH RANGE FRIDAY AFTERNOON.
DESPITE THESE CONDITIONS...THE NCFS REPORTS RELATIVELY HIGH FUEL
MOISTURE AT THIS TIME...AND THUS NO STATEMENTS REGARDING FIRE
WEATHER WILL BE ISSUED FOR FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...KC
SHORT TERM...BLS
LONG TERM...KRR
AVIATION...KC
FIRE WEATHER...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT THU OCT 18 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION LATE TONIGHT INTO EARLY FRIDAY.
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS AND SOUTHERN VIRGINIA IN
THE WAKE OF THE FRONT AND LINGER OVER THE AREA THROUGH SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 PM THURSDAY...
CLOUDS WILL INCREASE IN COVERAGE FROM WEST TO EAST THIS EVENING
AHEAD OF A COLD FRONT APPROACHING FROM THE WEST. AS OF THE 12Z UPPER
AIR ANALYSIS...UPPER LEVEL LOW PRESSURE WAS LOCATED OVER SRN MN/NRN
IA WITH THE TROUGH EXTENDING SOUTH INTO THE LOWER MS RIVER VALLEY.
BEST HEIGHT FALLS ARE STILL WELL TO THE NW...WITH A 140KT JET AT 250
MB OVER AR EXPECTED TO MOVE EASTWARD OVER THE APPALACHIANS LATER
TODAY. 16Z SURFACE ANALYSIS PLACES THE LOW OVER WI AND THE FRONT
EXTENDING EAST AND THEN SOUTH THROUGH THE OH AND TN VALLEYS. AS THIS
FRONT MIGRATES EASTWARD TODAY...WILL SEE INCREASING LOW-LEVEL
MOISTURE AND CLOUDS. AS FOR THE CONVECTION...THE 12Z NCEP WRF NMM
DEVELOPS A LINE OF SHOWERS OVER THE WESTERN PORTIONS OF THE AREA
BETWEEN 21Z AND 00Z...MAKING IT TO APPROX THE TRIANGLE AREA BEFORE
LIFTING NE AND DISSIPATING. THE 00Z NSSL WRF ARW SHOWS A SIMILAR
SCENARIO. GIVEN THE CURRENT SPC ANALYSES SHOWING INCREASING
LOW-LEVEL LAPSE RATES AHEAD OF THE DEVELOPING LINE OF SHOWERS AND
EFFECTIVE BULK SHEAR VALUES 45-50 KTS OVER THE MTS...CURRENTLY ABOUT
20 KTS OVER CENTRAL NC. ALSO...MUCAPE VALUES ARE AROUND 500 J/KG...
MAINLY ACROSS THE SOUTH. RUC ANALYSIS SHOWS BULK SHEAR VALUES
OVER CENTRAL NC INCREASING TO 50-60 KTS...WITH CAPE OF 500-1000
J/KG...MAINLY ACROSS THE WEST. THIS SUPPORTS THE POTENTIAL FOR
THUNDERSTORMS TO DEVELOP ACROSS THE WESTERN HALF OF THE AREA
TONIGHT...WITH AN ISOLATED STRONG TO SEVERE STORM POSSIBLE. MAIN
THREAT WOULD BE DAMAGING WINDS. SHOWERS AND ISOLATED STORMS ARE ALSO
POSSIBLE ALONG THE COASTAL PLAIN AHEAD OF THE MAIN LINE OF SHOWERS
AND STORMS THIS EVENING. HOW QUICKLY THE SHOWERS AND CLOUDS MOVE OUT
OF THE AREA WILL IMPACT THE LOW TEMPS FOR TONIGHT...BUT GENERALLY
LOOKING AT NEAR 50 DEGREES NW TO LOW 60S SE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AS OF 240 PM THURSDAY...
FRIDAY...
LARGE UPPER LOW OVER THE UPPER MIDWEST WILL MIGRATE EAST OVER THE
GREAT LAKES ON FRIDAY. THE COLD FRONT TO SLOWLY CROSS CENTRAL NC
TONIGHT IS FORECAST TO MOVE FROM ROUGHLY US HWY 1 AT 12Z TO WELL
EAST OF I-95 BY 18Z. EARLY IN THE DAY...FORCING FOR ACCENT WILL
MAINLY BE LIMITED TO UPPER DIVERGENCE IN THE RIGHT ENTRANCE OF THE
DEPARTING 120KT UPPER JET...WITH ONLY 30M HEIGHT FALLS AND
INCREASINGLY STABLE AND DRY AIR ALOFT. ANY REDEVELOPMENT OF SHOWERS
DURING THE FIRST HALF OF THE DAY WILL BE TIED TO WEAK FRONTAL
CONVERGENCE OVER THE COASTAL PLAIN...BUT EVEN THAT IS FORECAST TO
WEAKEN AS THE FLOW BECOMES MORE UNIDIRECTIONAL AND SOUTHWESTERLY.
WITH CLEARING SKIES AND A MODEST HEIGHT GRADIENT BEHIND THE
FRONT...FORECAST SOUNDINGS SHOW BOUNDARY LAYER MIXING...GREATEST IN
THE WEST...LEADING TO SOUTHWESTERLY WIND GUSTS OF UP TO 20-25KT
DURING THE AFTERNOON. A LOW LEVEL TRAJECTORY OUT OF THE SOUTHWEST
BEHIND THE FRONT WILL NOT LEAD TO A LARGE COOL DOWN BASED ON THE
UPSTREAM AIRMASS...WITH MOST GUIDANCE SHOWING HIGHS OF 70-78
NORTHWEST TO SOUTHEAST.
FRIDAY NIGHT...
OTHER THAN THE POTENTIAL FOR MID CLOUDS PASSING THROUGH THE BASE OF
THE UPPER LEVEL LOW...WHICH WILL BEGIN TO OPEN UP BY SATURDAY
MORNING...SKIES SHOULD BE MOSTLY CLEAR. AGAIN THERE IS NO REAL
STRONG COLD ADVECTION SATURDAY NIGHT AND LOWS SHOULD SETTLE JUST
BELOW NORMAL INTO THE MID TO UPPER 40S FOR MOST AREAS.
SATURDAY THROUGH SUNDAY......
THE MEAN TROUGH AXIS IS FORECAST TO CROSS THE APPALACHIANS AS
THE UPPER LOW OPENS AND LIFTS NORTHEASTWARD ON SATURDAY. THE
COMBINATION OF UPSTREAM MOISTURE AND THE COLDEST AIR ALOFT PASSING
OVERHEAD SHOULD LEAD TO ENHANCED STRATOCU IN THE LEE OF THE
MOUNTAINS DURING THE AFTERNOON. 1000-850MB THICKNESSES HOVER IN THE
1360S DURING THE DAY WITH A WEAK DOWNSLOPE FLOW POTENTIALLY
OFFSETTING WEAK COLD ADVECTION. THUS...WILL KEEP HIGHS WITHIN A
COUPLE DEGREES OF THOSE BASED ON THICKNESSES...66-73 NORTHWEST TO
SOUTHEAST. LOWS SATURDAY NIGHT IN THE LOW TO MID 40S UNDER MOSTLY
CLEAR SKIES...ALTHOUGH FORECAST SOUNDINGS SUGGEST CONDITIONS COULD
BE FAVORABLE FOR SOME OROGRAPHIC CIRRUS. HIGH PRESSURE WILL BEGIN TO
BUILD INTO THE AREA FROM THE SOUTHWEST SUNDAY WITH MOSTLY SUNNY
SKIES AND HIGHS AROUND 70S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 250 PM THURSDAY...
OVERALL...THIS PERIOD WILL BE DOMINATED BY HIGH PRESSURE BOTH AT THE
SURFACE AND ALOFT. SURFACE HIGH PRESSURE WILL SETTLE RIGHT OVER THE
REGION...WHILE A MID LEVEL RIDGE WILL BUILD IN FROM THE GULF COAST
AREA. THIS WILL RESULT IN A PROLONGED PERIOD OF DRY CONDITIONS. AS
HEIGHTS GRADUALLY INCREASE THROUGHOUT THE PERIOD...TEMPS WILL SLOWLY
MODERATE...WITH HIGHS TRENDING TO ABOVE NORMAL. HOWEVER...WITH
FAIRLY DRY AIR IN PLACE AND MOSTLY CLEAR SKIES...OUR DIURNAL RANGE
SHOULD BE LARGE...WITH OVERNIGHT LOWS ABLE TO DROP OFF INTO THE 40S.
A BACK DOOR FRONT MAY APPROACH THE REGION LATE IN THE PERIOD...BUT
AS OF NOW MODELS SHOW LITTLE IMPACT TO THE AREA.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM THURSDAY...
24 HOUR TAF PERIOD:
CHALLENGING TAF FORECAST WITH REGARD TO TIMING OF PRECIP AHEAD OF A
COLD FRONT MOVING IN FROM THE WEST OVERNIGHT AND INTO FRIDAY. BEST
CHANCE OF RAIN BEGINNING AROUND 00Z AT KINT AND KGSO...AND CLOSER TO
03Z-05Z ELSEWHERE. STILL QUITE A BIT OF UNCERTAINTY WITH REGARD
TO COVERAGE AND INTENSITY OF PRECIP AS WELL. VISBYS COULD GO DOWN TO
MVFR/IFR WHERE PRECIP IS OCCURRING...AND MVFR/IFR CIGS AND VISBYS
WITH FOG/STRATUS CONDITIONS BEGINNING AFTERWARD. CEILINGS HAVE
ALREADY GONE TO MVFR AT KINT AND KGSO AND ASIDE FROM SOME BRIEF
SCATTERING...WILL LIKELY REMAIN MVFR THE REMAINDER OF THE AFTERNOON.
CEILINGS AT THE REMAINING TERMINALS SHOULD REMAIN LOW END VFR...
POTENTIALLY DROPPING TO HIGH END MVFR BEFORE MIDNIGHT. WINDS ARE
EXPECTED TO BE GUSTY AT ALL TERMINALS THIS AFTERNOON...MAINLY OUT OF
THE SOUTH. CIG AND VISBY RESTRICTIONS SHOULD START CLEARING UP AFTER
SUNRISE FRIDAY AS DRIER AIR MOVES IN BEHIND THE FRONT.
FRIDAY NIGHT THROUGH TUESDAY:
WITH THE EXCEPTION OF SOME LINGERING SHOWERS ALONG THE COASTAL PLAIN
FRIDAY AFTERNOON...THE PRECIP AND OVERCAST SKIES SHOULD BE OUT OF
CENTRAL NC BY 15Z AND 21Z FRIDAY...RESPECTIVELY AS THE COLD FRONT
PUSHES THROUGH THE AREA. WINDS WILL BE GUSTY BEHIND THE FRONT...
POTENTIALLY 20 KTS OR MORE AT TIMES. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT AND LINGER THROUGH TUESDAY...RESULTING IN VFR
CONDITIONS FOR THE REMAINDER OF THE PERIOD.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...KC
SHORT TERM...BLS
LONG TERM...KRR
AVIATION...KC
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
506 PM EDT THU OCT 18 2012
.SYNOPSIS...
A DEEP LOW PRESSURE SYSTEM WILL LINGER TO OUR NORTHWEST AS A COLD
FRONT MOVES OFF THE SOUTH CAROLINA COAST ON FRIDAY. DRY HIGH PRESSURE
WILL THEN BUILD IN BEHIND THE FRONT OVER THE WEEKEND AND REMAIN IN
PLACE WELL INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
2100 UTC UPDATE...NO MAJOR CHANGES NEEDED TO THE FCST. SKY COVER
WILL BE TWEAKED TO ACCOUNT FOR STCU DISSIPATING AND REDEVELOPING
WHILE GENERALLY SHIFTING EAST. POPS WILL BE LEFT AS IS WITH LOW END
CHANCES ACROSS THE FARTHER NW ZONES. RADAR RETURNS AND THE LATEST
HRRR SUPPORT A LOW MENTION OVER THE NEXT FEW HRS...ESP ACROSS THE
ERN MOST NC COUNTIES.
THIS AFTERNOON...STRATUS OVER THE MOUNTAINS AND HIGHER UPSTATE
TERRAIN SHOULD GRADUALLY MIX OUT FROM THE EDGES INWARD. SCATTERED
CUMULUS WILL LIKELY FILL IN THE AREAS SHORTLY AFTER CLEARING OCCURS.
SURFACE FRONT STILL ACROSS THE MID TN VALLEY NOW PRODUCING SOME
LIGHT PRECIP WITH A FEW SCATTERED CONVECTIVE CELLS OVER NE TN. THIS
IS VERY SIMILAR TO DEPICTION ON 15Z HRRR RUN. THE NE TN ACTIVITY
AFFECTS MAINLY THE NRN PORTION OF THE CWA IN THAT DEPICTION WHILE
THE LIGHTER MORE STRATIFORM ACTIVITY DOES NOT MAKE IT ACROSS THE
MOUNTAINS. THIS SUPPORTS EARLIER DECISION TO KEEP CHANCE POPS IN THE
NRN CWA NEAR THE SUPPORT FROM THE UPPER TROUGH. IN THE FAR EASTERN
CWA WHERE SKIES CLEARED EARLIER AND THERE HAS BEEN MORE TIME TO
DESTABILIZE...PROG SOUNDINGS SHOW 500 J OR SO OF CAPE WHICH
WARRANTED A CHC MENTION THERE. DEPENDING ON HOW SOON THE STRATUS
CLEAR OUT IN THE WEST AND DESTABILIZATION OCCURS...SUBSEQUENT
REVISIONS MAY NEED TO BE MADE TO INCREASE POPS IN THAT AREA.
FRONT SHOULD BE EAST OF THE CWA BY MID EVENING AND CLEAR SKIES
SHOULD PROGRESS EASTWARD. TEMPS SHOULD BE NEAR NORMAL AS WINDS WILL
KEEP THE AREA FROM EXPERIENCING PRIME RADIATIONAL COOLING AND ALSO
LIKELY KEEPING FOG AT BAY. SFC DEWPOINTS SHOULD GRADUALLY DROP
OVERNIGHT WHICH WILL INHIBIT FOG FORMATION AS WELL.
CLEAR SKIES AND COOL AIR ALOFT WILL CAUSE DEEP MIXING ON FRIDAY.
THIS WILL ALLOW STRONG WINDS TO MIX DOWN TO THE SURFACE...GENERALLY
IN THE 20 TO 25 KT RANGE...BUT SOMEWHAT HIGHER OVER THE MOUNTAINS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM THURSDAY...A DEEP UPPER LOW OVER THE GREAT LAKES WILL
BEGIN TO SLOWLY SHIFT NORTHEAST AND REACH NORTHERN NEW ENGLAND ON
SUNDAY. MODEL GUIDANCE KEEPS THE DEEPER MOISTURE ASSOCIATED WITH THE
LARGE LOW TO THE NORTH OF THE AREA. HENCE...EXCEPT FOR SOME CLOUDS
ACROSS THE NC MOUNTAINS FRI NIGHT...GENERALLY CLEAR CONDITIONS ARE
ANTICIPATED SAT THROUGH SUN AS SURFACE HIGH PRESSURE GRADUALLY
BUILDS EAST OVER THE REGION.
MOS GUIDANCE IS RATHER CHILLY OVER THE MOUNTAINS FOR BOTH FRI NIGHT
AND SAT NIGHT WITH GENERALLY MID 30S FOR LOWS. THERE MAY BE ENOUGH
WIND/CLOUDS FRI NIGHT TO PRECLUDE WIDESPREAD FROST...BUT CONDITIONS
SAT NIGHT WILL FAVOR WIDESPREAD FROST AS HIGH PRESSURE SETTLES OVER
THE AREA. MAX TEMPS WILL BE NEAR CLIMO PER A MOS BLEND.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
AS OF 215 PM THURSDAY...LOOKS LIKE THE MEDIUM RANGE WILL BE QUIET
WITH TEMPS ABOVE CLIMO. ALL THE MEDIUM RANGE MODELS BUILD AN UPPER
RIDGE OVER THE EASTERN U.S. THE FIRST PART OF THE NEW WORK WEEK AND
IT THEN HOLDS SWAY INTO THE END OF THE WEEK. A BACKDOOR COLD FRONT
MAY APPROACH THU PER HPC/GFS GUIDANCE...BUT THE 00Z ECM KEEPS IT WELL NORTH
OF THE FORECAST AREA. THEREFORE...EXPECT SURFACE HIGH PRESSURE TO
PROVIDE MOSTLY CLEAR CONDITIONS THROUGH THE PERIOD WITH THE
AFOREMENTIONED SEASONALLY WARM CONDITIONS.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
2100 UTC UPDATE...DIDN/T SEE MUCH REASON TO KEEP TEMPO TS GOING
UNTIL 23Z SO REMOVED MENTION. SOME -SHRA ARE DEVELOPING WELL EAST OF
THE TERMINAL ALONG A LINE N/S. THE HRRR HAS PREDICTED THIS WELL AND
WILL GO WITH A NON/THREAT TSTMS AT KCLT AS ADVERTISED BY THAT
MODEL.
AT KCLT...LOW VFR CU HAVE RAPIDLY BROKEN OUT NEAR THE AIRFIELD.
EXPECT BASES OF THESE CU TO GRADUALLY RAISE THIS AFTERNOON. MODELS
STILL NOT THAT CONSISTENT WITH CONVECTIVE CHANCES TODAY...BUT THEY
ALL SEEM TO HAVE OVERDONE PRECIP THIS MORNING AROUND THE REGION.
THERE IS ENOUGH INSTABILITY FORECAST BY NAM AND RUC MODELS TO
WARRANT A TEMPO FOR THUNDER THOUGH CONFIDENCE IS FAIRLY LOW GIVEN
THE POOR PERFORMANCE SO FAR TODAY. WINDS WILL GRADUALLY SHIFT TO THE
SOUTHWEST WITH FRONTAL PASSAGE TONIGHT.
ELSEWHERE...CONVECTIVE CHANCES THIS AFTERNOON WILL BE BEST ACROSS
THE NORTHERN AND FAR EASTERN PORTIONS OF THE AREA...THE NORTH BEING
NEARER A PASSING SHORTWAVE TROUGH AND THE EAST SEEING THE MOST
INSTABILITY AHEAD OF THE APPROACHING COLD FRONT. KHKY LOOKS LIKE THE
MOST LIKELY SITE TO BE AFFECTED BY PRECIP/THUNDER...BUT CONFIDENCE
IS LOW ENOUGH I WILL ONLY MENTION VCTS. BEHIND THE FRONT SOME CIRRUS
WILL REMAIN OVERHEAD INTO TOMORROW WITH UPPER LEVEL LOW STILL
SPINNING TO OUR NORTHWEST. CLEAR ENOUGH TONIGHT THAT GOOD
RADIATIONAL COOLING SHOULD OCCUR THOUGH WINDS WILL NOT BE ABLE TO
CALM COMPLETELY AND WE WILL ALSO SEE MOISTURE DIMINISH AFTER THE
FRONTAL PASSAGE...SO NOT ANTICIPATING ANY VSBY RESTRICTIONS DUE TO
FOG TONIGHT.
OUTLOOK...EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE WEEKEND. THE
EXCEPTION WILL BE EARLY MORNING MOUNTAIN VALLEY FOG DURING THAT
TIMEFRAME. WINDS MAY GUST TO 20 KT OR MORE AT TIMES OVER THE REGION
FRIDAY AFTERNOON.
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
&&
.FIRE WEATHER...
MAXIMUM TEMPERATURES IN THE 60S ACROSS THE MTNS AND 70S FOOTHILLS
AND PIEDMONT ON FRIDAY WILL COMBINE WITH DRIER DEW POINTS ACROSS THE
REGION TO PUSH AFTERNOON RH VALUES DOWN INTO THE 25 TO 30 PERCENT
RANGE FRI AFTN. IN ADDITION...BREEZY SW WINDS ARE EXPECTED THROUGH
THE DAY WITH OCCASIONAL GUSTS IN THE 25 TO 30 KT RANGE. DEPENDING
UPON HOW MUCH RAIN FALLS AHEAD OF THE FRONT PASSING THIS
AFTN/EVENING...FUELS COULD BE DRY ENOUGH TO CREATE HEIGHTENED FIRE
DANGER IN SOME AREAS FRI AFTN. RAIN CHANCES ARE BEST OVER THE NRN
MOUNTAINS AND ERN PIEDMONT. THIS WILL NEED TO BE MONITORED CLOSELY
THROUGH THU.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...LG
AVIATION...SBK/WIMBERLEY
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
243 PM EDT THU OCT 18 2012
.SYNOPSIS...
A DEEP LOW PRESSURE SYSTEM WILL LINGER TO OUR NORTHWEST AS A COLD
FRONT MOVES OFF THE SOUTH CAROLINA COAST ON FRIDAY. DRY HIGH PRESSURE
WILL THEN BUILD IN BEHIND THE FRONT OVER THE WEEKEND AND REMAIN IN
PLACE WELL INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
THIS AFTERNOON...STRATUS OVER THE MOUNTAINS AND HIGHER UPSTATE
TERRAIN SHOULD GRADUALLY MIX OUT FROM THE EDGES INWARD. SCATTERED
CUMULUS WILL LIKELY FILL IN THE AREAS SHORTLY AFTER CLEARING OCCURS.
SURFACE FRONT STILL ACROSS THE MID TN VALLEY NOW PRODUCING SOME
LIGHT PRECIP WITH A FEW SCATTERED CONVECTIVE CELLS OVER NE TN. THIS
IS VERY SIMILAR TO DEPICTION ON 15Z HRRR RUN. THE NE TN ACTIVITY
AFFECTS MAINLY THE NRN PORTION OF THE CWA IN THAT DEPICTION WHILE
THE LIGHTER MORE STRATIFORM ACTIVITY DOES NOT MAKE IT ACROSS THE
MOUNTAINS. THIS SUPPORTS EARLIER DECISION TO KEEP CHANCE POPS IN THE
NRN CWA NEAR THE SUPPORT FROM THE UPPER TROUGH. IN THE FAR EASTERN
CWA WHERE SKIES CLEARED EARLIER AND THERE HAS BEEN MORE TIME TO
DESTABILIZE...PROG SOUNDINGS SHOW 500 J OR SO OF CAPE WHICH
WARRANTED A CHC MENTION THERE. DEPENDING ON HOW SOON THE STRATUS
CLEAR OUT IN THE WEST AND DESTABILIZATION OCCURS...SUBSEQUENT
REVISIONS MAY NEED TO BE MADE TO INCREASE POPS IN THAT AREA.
FRONT SHOULD BE EAST OF THE CWA BY MID EVENING AND CLEAR SKIES
SHOULD PROGRESS EASTWARD. TEMPS SHOULD BE NEAR NORMAL AS WINDS WILL
KEEP THE AREA FROM EXPERIENCING PRIME RADIATIONAL COOLING AND ALSO
LIKELY KEEPING FOG AT BAY. SFC DEWPOINTS SHOULD GRADUALLY DROP
OVERNIGHT WHICH WILL INHIBIT FOG FORMATION AS WELL.
CLEAR SKIES AND COOL AIR ALOFT WILL CAUSE DEEP MIXING ON FRIDAY.
THIS WILL ALLOW STRONG WINDS TO MIX DOWN TO THE SURFACE...GENERALLY
IN THE 20 TO 25 KT RANGE...BUT SOMEWHAT HIGHER OVER THE MOUNTAINS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM THURSDAY...A DEEP UPPER LOW OVER THE GREAT LAKES WILL
BEGIN TO SLOWLY SHIFT NORTHEAST AND REACH NORTHERN NEW ENGLAND ON
SUNDAY. MODEL GUIDANCE KEEPS THE DEEPER MOISTURE ASSOCIATED WITH THE
LARGE LOW TO THE NORTH OF THE AREA. HENCE...EXCEPT FOR SOME CLOUDS
ACROSS THE NC MOUNTAINS FRI NIGHT...GENERALLY CLEAR CONDITIONS ARE
ANTICIPATED SAT THROUGH SUN AS SURFACE HIGH PRESSURE GRADUALLY
BUILDS EAST OVER THE REGION.
MOS GUIDANCE IS RATHER CHILLY OVER THE MOUNTAINS FOR BOTH FRI NIGHT
AND SAT NIGHT WITH GENERALLY MID 30S FOR LOWS. THERE MAY BE ENOUGH
WIND/CLOUDS FRI NIGHT TO PRECLUDE WIDESPREAD FROST...BUT CONDITIONS
SAT NIGHT WILL FAVOR WIDESPREAD FROST IN THE MOUNTAINS AS HIGH
PRESSURE SETTLES OVER THE AREA. MAX TEMPS WILL BE NEAR CLIMO PER A
MOS BLEND.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
AS OF 215 PM THURSDAY...LOOKS LIKE THE MEDIUM RANGE WILL BE QUIET
WITH TEMPS ABOVE CLIMO. ALL THE MEDIUM RANGE MODELS BUILD AN UPPER
RIDGE OVER THE EASTERN U.S. THE FIRST PART OF THE NEW WORK WEEK AND
IT THEN HOLDS SWAY INTO THE END OF THE WEEK. A BACKDOOR COLD FRONT
MAY APPROACH THU PER HPC/GFS GUIDANCE...BUT THE 00Z ECM KEEPS IT WELL NORTH
OF THE FORECAST AREA. THEREFORE...EXPECT SURFACE HIGH PRESSURE TO
PROVIDE MOSTLY CLEAR CONDITIONS THROUGH THE PERIOD WITH THE
AFOREMENTIONED SEASONALLY WARM CONDITIONS.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...LOW VFR CU HAVE RAPIDLY BROKEN OUT NEAR THE AIRFIELD.
EXPECT BASES OF THESE CU TO GRADUALLY RAISE THIS AFTERNOON. MODELS
STILL NOT THAT CONSISTENT WITH CONVECTIVE CHANCES TODAY...BUT THEY
ALL SEEM TO HAVE OVERDONE PRECIP THIS MORNING AROUND THE REGION.
THERE IS ENOUGH INSTABILITY FORECAST BY NAM AND RUC MODELS TO
WARRANT A TEMPO FOR THUNDER THOUGH CONFIDENCE IS FAIRLY LOW GIVEN
THE POOR PERFORMANCE SO FAR TODAY. WINDS WILL GRADUALLY SHIFT TO THE
SOUTHWEST WITH FRONTAL PASSAGE TONIGHT.
ELSEWHERE...CONVECTIVE CHANCES THIS AFTERNOON WILL BE BEST ACROSS
THE NORTHERN AND FAR EASTERN PORTIONS OF THE AREA...THE NORTH BEING
NEARER A PASSING SHORTWAVE TROUGH AND THE EAST SEEING THE MOST
INSTABILITY AHEAD OF THE APPROACHING COLD FRONT. KHKY LOOKS LIKE THE
MOST LIKELY SITE TO BE AFFECTED BY PRECIP/THUNDER...BUT CONFIDENCE
IS LOW ENOUGH I WILL ONLY MENTION VCTS. BEHIND THE FRONT SOME CIRRUS
WILL REMAIN OVERHEAD INTO TOMORROW WITH UPPER LEVEL LOW STILL
SPINNING TO OUR NORTHWEST. CLEAR ENOUGH TONIGHT THAT GOOD
RADIATIONAL COOLING SHOULD OCCUR THOUGH WINDS WILL NOT BE ABLE TO
CALM COMPLETELY AND WE WILL ALSO SEE MOISTURE DIMINISH AFTER THE
FRONTAL PASSAGE...SO NOT ANTICIPATING ANY VSBY RESTRICTIONS DUE TO
FOG TONIGHT.
OUTLOOK...EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE WEEKEND. THE
EXCEPTION WILL BE EARLY MORNING MOUNTAIN VALLEY FOG DURING THAT
TIMEFRAME. WINDS MAY GUST TO 20 KT OR MORE AT TIMES OVER THE REGION
FRIDAY AFTERNOON.
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
&&
.FIRE WEATHER...
MAXIMUM TEMPERATURES IN THE 60S ACROSS THE MTNS AND 70S FOOTHILLS
AND PIEDMONT ON FRIDAY WILL COMBINE WITH DRIER DEW POINTS ACROSS THE
REGION TO PUSH AFTERNOON RH VALUES DOWN INTO THE 25 TO 30 PERCENT
RANGE FRI AFTN. IN ADDITION...BREEZY SW WINDS ARE EXPECTED THROUGH
THE DAY WITH OCCASIONAL GUSTS IN THE 25 TO 30 KT RANGE. DEPENDING
UPON HOW MUCH RAIN FALLS AHEAD OF THE FRONT PASSING THIS
AFTN/EVENING...FUELS COULD BE DRY ENOUGH TO CREATE HEIGHTENED FIRE
DANGER IN SOME AREAS FRI AFTN. RAIN CHANCES ARE BEST OVER THE NRN
MOUNTAINS AND ERN PIEDMONT. THIS WILL NEED TO BE MONITORED CLOSELY
THROUGH THU.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...WIMBERLEY
SHORT TERM...LG
LONG TERM...LG
AVIATION...WIMBERLEY
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
140 PM EDT THU OCT 18 2012
.SYNOPSIS...
A DEEP LOW PRESSURE SYSTEM WILL LINGER TO OUR NORTHWEST AS A COLD
FRONT MOVES OFF THE SOUTH CAROLINA COAST ON FRIDAY. DRY HIGH PRESSURE
WILL THEN BUILD IN BEHIND THE FRONT OVER THE WEEKEND AND REMAIN IN
PLACE WELL INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM EDT...REMOVED PRECIP CHANCES FOR THIS MORNING AS THE
PREFRONTAL ACTIVITY HAS DISSIPATED. RADAR ALSO INDICATES THE FRONTAL
SHOWERS OVER THE CUMBERLAND PLATEAU ARE ALSO STRUGGLING. LATEST
GUIDANCE PUTS HIGHEST POPS THIS AFTERNOON ACROSS THE NORTHERN
PORTION OF THE CWFA WHERE UPPER LEVEL SUPPORT FROM LIFTING SHORTWAVE
WILL BE BEST. PROG SOUNDINGS /EXCEPT THOSE FROM 06Z NAM/ ARE NOT
IMPRESSIVE AND MODELS HAVE GENERALLY OVERDONE THE PRECIP AROUND THE
REGION THIS MORNING. WILL LOWER POPS...KEEPING ONLY A LOW CHANCE
OVER THE NORTH AND ALSO OVER THE EAST WHICH HAS THE MOST POTENTIAL
TO DESTABILIZE AHEAD OF THE FROPA...AND A SLIGHT CHANCE ELSEWHERE.
PREVIOUS DISCUSSION...A STRONG SHORT WAVE MOVES ACROSS THE AREA
TODAY AS IT SWINGS AROUND A STRENGTHENING UPPER LOW DROPPING INTO
THE MID WEST. THIS WAVE PUSHES A COLD FRONT...CURRENTLY JUST WEST OF
THE MS VALLEY...ACROSS THE AREA AS WELL. LATEST MESOSCALE GUIDANCE
HAS SLOWED THE MOVEMENT OF THIS SYSTEM. IT ALSO WEAKENS THE
PRE-FRONTAL CONVECTION AS IT MOVES INTO THE WRN CWFA. CONVECTION
THEN REDEVELOPS ALONG THE FRONT ACROSS THE FOOTHILLS AND PIEDMONT
FOR THE AFTERNOON AND SLIDES EASTWARD THRU THE LATE AFTERNOON. THE
SYNOPTIC GUIDANCE GENERALLY AGREES WITH THIS AS WELL AS IT WEAKENS
THE INITIAL PUSH OF QG FORCING...THEN REDEVELOPS IT FOR THE
AFTERNOON. THEREFORE...HAVE FOLLOWED THESE TRENDS WITH THE POP FCST.
THE TRICKY PART IS DETERMINING THE HOW HIGH THE ACTUAL POP VALUES
WILL BE. EXPECT NUMEROUS SHOWERS AS THE CONVECTION MOVES IN...BUT
DIMINISHING AS IT MOVES EAST. THEN... HOW WIDESPREAD WILL THE
REDEVELOPING CONVECTION BE. HAVE GONE WITH A MDL BLEND WHICH KEEPS
POP GENERALLY IN THE CHC RANGE XCPT FOR THE WRN CWFA WHERE THE
CONVECTION INITIALLY MOVES IN. THE SECOND CONCERN IS SEVERE WX
POTENTIAL. ALTHOUGH THERE IS STRONG SHEAR AND HELICITY WITH THE
PRE-FRONTAL PRECIP...THERE IS NO INSTABILITY WITH THE STRONG
INVERSION IN PLACE. BEST CHC OF SEVERE WILL BE OUTSIDE OF THE MTNS
THIS AFTERNOON WITH THE CONVECTION REDEVELOPING ALONG THE FRONT.
MODERATE INSTABILITY DEVELOPS AND SHEAR REMAINS STRONG...ALTHOUGH IT
WILL BE UNIDIRECTIONAL IN NATURE. EXPECT DAMAGING WIND GUSTS TO BE
THE MAIN SVR THREAT.
THE CONVECTION WILL LINGER OVER THE I-77 CORRIDOR DURING THE EVENING
THEN MOVE EAST BY MIDNIGHT. SOME OF THE GUIDANCE SUGGESTS THE SYSTEM
WILL SLOW DURING THE EVENING. HOWEVER...THE STALL THE SYSTEM TO OUR
EAST. SKIES CLEAR SLOWLY FROM WEST TO EAST OVERNIGHT. LOWS WILL BE
NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 300 AM THURSDAY...A DEEP VORTEX WILL BEGIN TO FILL AND SLOWLY
SHIFT EAST ACRS THE GREAT LAKES FRIDAY AND SATURDAY. MODELS IN
AGREEMENT ON A STRONG DRY SLOT ROUNDING THE SOUTH SIDE OF THE VORTEX
INTO THE CWFA ON FRIDAY...THEN SHIFTING EAST FRIDAY NIGHT. FCST
SNDGS INDICATE VERY DRY PROFILES WITH DEEP MIXING FRI AFTN...WITH
SFC DEWPTS POSSIBLY DROPPING INTO THE UPR 20S TO LWR 30S DURING PEAK
MIXING. MEANWHILE...H8 TEMPS DROP TO THE 6-8 C RANGE WITHIN WSWLY
FLOW. SO TEMPS ARE EXPECTED TO STRUGGLE TO GET TO UPR 60S TO LWR 70S
EAST OF THE MTNS...DESPITE SUNNY SKIES AND DRY AIR. STILL...AFTN RH
VALUES LIKELY TO DROP INTO THE MID TO UPR 20S...WHICH COMBINED WITH
BREEZY CONDITIONS MAY ENHANCE FIRE DANGER (SEE FIRE WX SECTION
BELOW).
FRIDAY NIGHT AND SATURDAY...WRAP AROUND MOISTURE WILL BRUSH ALONG
THE TN/NC BORDER AS THE AFOREMENTIONED VORTEX BEGINS TO MOVE EAST.
FLOW EVENTUALLY SHIFTS FROM WSW TO NW BY SATURDAY MORNING. H8 TEMPS
DROP TO ABOUT 2-4 C WITH THE MOISTURE AND NW UPSLOPE. SO ONLY
EXPECTING A PERIOD STRATUS AND PERHAPS A FEW SPRINKLES.
OTHERWISE...NO FROST/FREEZE/WINTRY CONCERNS EXPECTED. TEMPS WILL BE
ONE OR TWO CATEGORIES BELOW NORMAL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
AS OF 215 PM THURSDAY...LOOKS LIKE THE MEDIUM RANGE WILL BE QUIET
WITH TEMPS ABOVE CLIMO. ALL THE MEDIUM RANGE MODELS BUILD AN UPPER
RIDGE OVER THE EASTERN U.S. THE FIRST PART OF THE NEW WORK WEEK AND
IT THEN HOLDS SWAY INTO THE END OF THE WEEK. A BACKDOOR COLD FRONT
MAY APPROACH THU PER HPC/GFS GUIDANCE...BUT THE 00Z ECM KEEPS IT WELL NORTH
OF THE FORECAST AREA. THEREFORE...EXPECT SURFACE HIGH PRESSURE TO
PROVIDE MOSTLY CLEAR CONDITIONS THROUGH THE PERIOD WITH THE
AFOREMENTIONED SEASONALLY WARM CONDITIONS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...LOW VFR CU HAVE RAPIDLY BROKEN OUT NEAR THE AIRFIELD.
EXPECT BASES OF THESE CU TO GRADUALLY RAISE THIS AFTERNOON. MODELS
STILL NOT THAT CONSISTENT WITH CONVECTIVE CHANCES TODAY...BUT THEY
ALL SEEM TO HAVE OVERDONE PRECIP THIS MORNING AROUND THE REGION.
THERE IS ENOUGH INSTABILITY FORECAST BY NAM AND RUC MODELS TO
WARRANT A TEMPO FOR THUNDER THOUGH CONFIDENCE IS FAIRLY LOW GIVEN
THE POOR PERFORMANCE SO FAR TODAY. WINDS WILL GRADUALLY SHIFT TO THE
SOUTHWEST WITH FRONTAL PASSAGE TONIGHT.
ELSEWHERE...CONVECTIVE CHANCES THIS AFTERNOON WILL BE BEST ACROSS
THE NORTHERN AND FAR EASTERN PORTIONS OF THE AREA...THE NORTH BEING
NEARER A PASSING SHORTWAVE TROUGH AND THE EAST SEEING THE MOST
INSTABILITY AHEAD OF THE APPROACHING COLD FRONT. KHKY LOOKS LIKE THE
MOST LIKELY SITE TO BE AFFECTED BY PRECIP/THUNDER...BUT CONFIDENCE
IS LOW ENOUGH I WILL ONLY MENTION VCTS. BEHIND THE FRONT SOME CIRRUS
WILL REMAIN OVERHEAD INTO TOMORROW WITH UPPER LEVEL LOW STILL
SPINNING TO OUR NORTHWEST. CLEAR ENOUGH TONIGHT THAT GOOD
RADIATIONAL COOLING SHOULD OCCUR THOUGH WINDS WILL NOT BE ABLE TO
CALM COMPLETELY AND WE WILL ALSO SEE MOISTURE DIMINISH AFTER THE
FRONTAL PASSAGE...SO NOT ANTICIPATING ANY VSBY RESTRICTIONS DUE TO
FOG TONIGHT.
OUTLOOK...EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE WEEKEND. THE
EXCEPTION WILL BE EARLY MORNING MOUNTAIN VALLEY FOG DURING THAT
TIMEFRAME. WINDS MAY GUST TO 20 KT OR MORE AT TIMES OVER THE REGION
FRIDAY AFTERNOON.
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
&&
.FIRE WEATHER...
MAXIMUM TEMPERATURES IN THE 60S ACROSS THE MTNS AND 70S FOOTHILLS
AND PIEDMONT ON FRIDAY WILL COMBINE WITH DRIER DEW POINTS ACROSS THE
REGION TO PUSH AFTERNOON RH VALUES DOWN INTO THE 25 TO 30 PERCENT
RANGE FRI AFTN. IN ADDITION...BREEZY SW WINDS ARE EXPECTED THROUGH
THE DAY. DEPENDING UPON HOW MUCH RAIN FALLS WITH THE FRONTAL PASSAGE
THURSDAY...FUELS COULD BE DRY ENOUGH TO CREATE HEIGHTENED FIRE
DANGER IN SOME AREAS FRI AFTN. THIS WILL NEED TO BE MONITORED
CLOSELY THROUGH THU.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...RWH/WIMBERLEY
SHORT TERM...ARK
LONG TERM...ARK/JPT
AVIATION...WIMBERLEY
FIRE WEATHER...ARK
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
327 PM CDT THU OCT 18 2012
.DISCUSSION...
CLOUDS ARE BEGINNING TO ERODE ACROSS SOUTHEAST TEXAS AND AM
EXPECTING SKIES TO BECOME MOSTLY CLEAR THIS EVENING. DRIER AIR
WILL CONTINUE TO FILTER INTO THE REGION AND OBSERVATIONS UPSTREAM
SHOW SFC DEW POINTS IN THE UPPER 20S TO LOWER 30S. WITH THE VERY
DRY AIR IN PLACE AND WINDS DECOUPLING...FEEL OVERNIGHT LOWS WILL
FALL INTO THE UPPER 40S AND LOWER 50S NORTH...MID 50S CENTRAL AND
MID 60S IMMEDIATE COAST. SURFACE HIGH PRESSURE WILL BRING MOSTLY
SUNNY SKIES AND WARM DAYTIME TEMPERATURES BOTH FRIDAY AND
SATURDAY. THE HIGH WILL SHIFT EAST ON SATURDAY AND ONSHORE WINDS
WILL BRING HIGHER HUMIDITY LEVELS BACK TO SOUTHEAST TEXAS. AN
UPPER LEVEL RIDGE AND A CORRESPONDING INCREASE IN 500 MB HEIGHTS
WILL ALLOW TEMPS TO WARM SUN/MON BUT THIS WARMING WILL BE TEMPERED
A BIT BY THE INCREASE IN MOISTURE AND CLOUD COVER. COULD BE SOME
STREAMER SHOWERS SUNDAY AND MONDAY AS FCST SOUNDINGS SHOW
SATURATION BENEATH A BUILDING CAP BUT FEEL RAIN CHANCES ARE TOO
SLIM TO MENTION AT THIS TIME. NOT EXPECTING MUCH DAY TO DAY CHANGE
THROUGH THE END OF NEXT WEEK AS UPPER LEVEL RIDGING IMPINGES ON
SOUTH TEXAS. WITH THE HIGH 500 MB HEIGHTS AND CONTINUED ONSHORE
FLOW...EXPECT UNSEASONABLY WARM TEMPERATURES FOR MOST OF NEXT
WEEK. 43
&&
.MARINE...
A TIGHT PRESSURE GRADIENT WILL HELP GENERATE WINDS TO ADVISORY
LEVELS THROUGH AT LEAST THIS EVENING. THE NAM12 AND RUC DIMINISH
THE WINDS TO SLIGHTLY BELOW ADVISORY LEVELS BY 06Z. WILL EXTEND
THE ADVISORY INTO THE EVENING FOR THE GULF WATERS.
HIGH PRESSURE WILL MOVE OVERHEAD LATER ON FRIDAY. EXPECT MODERATE
ONSHORE WINDS TO DEVELOP SATURDAY AFTERNOON. WIND SPEEDS MAY REACH
AT LEAST CAUTION LEVELS SATURDAY NIGHT INTO TUESDAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 52 83 57 87 69 / 0 0 0 0 10
HOUSTON (IAH) 55 84 58 87 70 / 0 0 0 0 10
GALVESTON (GLS) 67 80 70 82 76 / 0 0 0 0 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
254 PM CDT THU OCT 18 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
254 PM CDT THU OCT 18 2012
CLOSED LOW AND ITS INFLUENCE ON THE AREA THROUGH FRIDAY EVENING IS
IMMEDIATE FORECAST CONCERN...THEN ATTENTION TURNS TO WARMING
SATURDAY AND ESPECIALLY SUNDAY.
LATEST LOOP OF WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW CLOSED LOW
CENTERED OVER THE MN/IA/WI COMMON BORDER. RADAR MOSAIC SHOWING
WIDESPREAD SHOWER ACTIVITY ACROSS THE FORECAST AREA THANKS TO
INFLUENCE OF DEEP COLD/CYCLONIC FLOW OVERHEAD. TEMPERATURES
SUFFERING AS WELL WITH READINGS AT 2 PM ONLY IN THE 40S.
LATEST NCEP MODELS AS WELL AS THE ECMWF/GEM ALL IN VERY GOOD
AGREEMENT WITH SYNOPTIC SETUP THROUGH SUNDAY.
LOOK OF THE CLOSED LOW TO REMAIN ANCHORED OVER THE REGION
TONIGHT...MAKING A SLOW PUSH EAST TOWARD LAKE MICHIGAN BY LATE
FRIDAY AFTERNOON. BUFKIT MODEL SOUNDINGS SHOWING DEEP LAYER OF
MOISTURE WITH GENERALLY WEAK LIFT OVER THE AREA TONIGHT FOR
SCATTERED SHOWERS/AREAS OF DRIZZLE. WITH LIGHT WINDS AND SATURATED
LOWER BOUNDARY LAYER UNDER THE LOW...ALSO EXPECTING SOME LIGHT FOG
ACROSS THE AREA WITH VISIBILITY GENERALLY IN THE 3-6SM RANGE.
925-850MB LAYER TEMPERATURES COOL ONLY A COUPLE DEGREES TONIGHT.
WITH CLOUD COVER/SCATTERED PRECIPITATION...LOWS TONIGHT SHOULD
BOTTOM OUT IN THE UPPER 30S TO LOWER 40S. PLAN ON SCATTERED SHOWERS
ONCE AGAIN FOR FRIDAY WITH COLD/DEEP CYCLONIC FLOW CONTINUING. NOT
MUCH RECOVERY EXPECTED IN TEMPERATURES AS WELL WITH HIGHS TOPPING
OFF IN THE UPPER 40S TO A FEW LOWER 50S. A FEW LINGERING SHOWERS
WILL BE POSSIBLE ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN
FRIDAY EVENING AS LAST TROUGH ASSOCIATED WITH THE CLOSED LOW ROTATES
THROUGH THAT AREA. OTHERWISE FOR THE REST OF THE OVERNIGHT HOURS
MODELS PUSH THE CLOSED LOW MORE INTO THE GREAT LAKES REGION WHILE A
RIDGE OF HIGH PRESSURE BUILDS IN FROM THE PLAINS. NAM 925MB RH FIELD
INDICATING PERHAPS A FEW BREAKS IN THE STRATUS/STRATOCUMULUS LATER
FRIDAY NIGHT. THIS IS ALSO INDICATED IN THE BUFKIT SOUNDING...BUT
THEN DEVELOPS QUITE A BIT OF LOW-LEVEL STRATUS TOWARD MORNING.
BELIEVE MOSTLY CLOUDY IS THE WAY TO GO AT THIS POINT IN TIME. WILL
HAVE TO WATCH THIS SCENARIO CLOSELY. IF THERE IS SOME
CLEARING...COULD END UP WITH QUITE A BIT OF FOG WITH COOL/MOIST
LOWER BOUNDARY LAYER.
CLEARING SKIES AND WARMING EXPECTED SATURDAY AS THE CLOSED LOW
CONTINUES TO MOVE EAST OF THE REGION AND RIDGE OF HIGH PRESSURE BUILD
OVERHEAD. HIGHS SATURDAY SHOULD RESPOND NICELY TO SUNSHINE AND
925-850MB TEMPERATURES WARMING INTO THE 5-7C RANGE. PLAN ON HIGHS
PUSHING WELL INTO THE 50S. WARMING WILL CONTINUE INTO SUNDAY IN
SOUTHERLY FLOW AHEAD OF A COLD FRONT MOVING INTO THE DAKOTAS/WESTERN
MN. NAM INDICATING 925-850MB LAYER TEMPERATURES IN THE 14-17C RANGE.
THIS SHOULD EQUATE TO HIGHS SUNDAY IN THE 60S TO PERHAPS A FEW LOWER
70S WHICH WOULD BE SOME 15-20 DEGREES ABOVE NORMAL.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
254 PM CDT THU OCT 18 2012
LATEST GFS/ECMWF IN GOOD AGREEMENT THROUGH TUESDAY...THEN DIVERGE
SOMEWHAT WEDNESDAY AND THURSDAY WITH TIMING ISSUES WITH WAVES IN
SOUTHWEST FLOW ALOFT.
FOR SUNDAY NIGHT THROUGH TUESDAY...CYCLOGENESIS OVER THE CENTRAL
PLAINS TAKES PLACE WITH THE WAVE MOVING NORTHEAST TOWARD THE AREA.
BOTH MODELS SHOWING AMPLE AMOUNT OF 850MB MOISTURE TRANSPORT OUT OF
THE GULF AND INTO THE AREA AHEAD OF THE ADVANCING LOW AND WARM
FRONT. ALSO...MODELS PRODUCING ABOUT 300-600J/KG OF CAPE LATER
SUNDAY NIGHT INTO MONDAY FOR A GOOD CHANCE OF SHOWERS/EMBEDDED
THUNDERSTORMS. FOR WEDNESDAY AND THURSDAY...MODELS DIVERGE ON
AMOUNT OF CYCLOGENESIS AND TIMING OF LOW PRESSURE SYSTEMS MOVING
TOWARD THE AREA WITH SOUTHWEST FLOW ALOFT. TOOK A CONSENSUS APPROACH
FOR NOW WHICH YIELDS MID-RANGE POPS FOR SHOWERS/THUNDERSTORMS.
WILL HOPE FOR BETTER RESOLUTION IN THE MODELS WITH SUBSEQUENT RUNS.
EITHER WAY...LOOKS LIKE AN ACTIVE WEATHER WEEK SETTING UP WITH EVEN
THE OUT SIDE CHANCE OF STRONG-SEVERE THUNDERSTORMS DEPENDING ON
AVAILABLE CAPE/SHEAR. OTHERWISE...LOOKS LIKE TEMPERATURES WILL
REMAIN SOME 15 OR SO DEGREES ABOVE NORMAL.
&&
.AVIATION...THIS AFTERNOON THROUGH FRIDAY
1159 AM CDT THU OCT 18 2012
ENTIRE PERIOD WILL BE PROBLEMATIC WITH A MOIST SFC-500MB LOW
DRIFTING SLOWLY SOUTHEAST ACROSS THE UPPER MIDWEST. WIDESPREAD
STRATUS CLOUDS AND MVFR CIGS TO PREVAIL THRU FRI. WITH DIURNAL
COOLING AND THE CENTER OF THE SFC-MID LEVEL LOW OVER THE AREA
TONIGHT...CIGS EXPECTED TO FALL TO IFR AND VSBYS TO MVFR IN BR FROM
LATE THIS EVENING THRU MID MORNING FRI. WITH ALL THE MOISTURE AND
DEEP/COOL CYCLONIC CIRCULATION OVER THE AREA...AREAS DZ/-RA AND SCT
-SHRA WILL CONTINUE IN/AROUND THE AREA THRU TONIGHT/FRI. PRECIP
AMOUNTS LOOK TO BE ON THE LIGHT SIDE...WITH ANY FALLING PRECIP
HAVING MINIMAL IMPACT ON VSBYS...MUCH LIKE THE MORNING/MID DAY HOURS
TODAY WITH MOST LOCATIONS REPORTING 10SM. CONTINUED A -SHRA MENTION
IN TAFS THRU THIS AFTERNOON THEN CARRIED VCSH THRU TONIGHT INTO FRI
FOR NOW. WITH THE SFC LOW NEAR/OVERHEAD...WINDS WILL BE SOMEWHAT
VARIABLE IN DIRECTION BUT BE ON THE LIGHT SIDE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
254 PM CDT THU OCT 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...RRS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1202 PM CDT THU OCT 18 2012
.UPDATE...
A VORTICITY MAX ROTATING AROUND A CLOSED UPPER LOW CENTERED OVER THE
MN/WI/IA BORDER IS MOVING INTO SOUTHERN WI LATE THIS MORNING. EXPECT
THE DRIZZLE AND VERY LIGHT SHOWERS TO EXPAND INTO MORE NUMEROUS
LIGHT RAIN SHOWERS DURING THE AFTERNOON. THEY WILL BE SPREADING
NORTHEASTWARD FROM IOWA AND NORTHERN IL...AND PROBABLY SKIRT THE
SOUTHERN FORECAST AREA. SCATTERED COVERAGE EXPECTED IN THE NORTHERN
FORECAST AREA. THE LATEST HRRR SEEMS TO BE PICKING UP ON THIS TREND
AS WELL.
&&
.AVIATION/18Z TAFS/...
A LARGE AND SLOW MOVING LOW PRESSURE SYSTEM BRINGING MVFR CONDITIONS
TO MOST OF THE AREA TODAY. THE COMBINATION OF COLD TEMPS
ALOFT...STEEP LOW LEVEL LAPSE RATES AND SHORT WAVE ENERGY WRAPPING
AROUND THE UPPER LOW...WILL ALLOW FOR SCATTERED TO NUMEROUS SHOWERS
THIS AFTERNOON. AN AREA OF SHOWERS WILL BE MOVING IN FROM EASTERN
IOWA AND NORTHWEST IL EARLY THIS AFTERNOON. THE NUMEROUS SHOWERS
SHOULD MAINLY SKIRT THE SOUTHERN WI/NORTHERN IL BORDER...WHILE
SCATTERED SHOWERS SHOULD BE TOWARD CENTRAL WI FROM MSN NORTH.
MVFR CEILINGS SHOULD CONTINUE AT MSN AND PROBABLY UES...WITH
INTERMITTENT FUEL ALTERNATE CIGS DURING RAIN SHOWERS. CIGS SHOULD
IMPROVE/REMAIN VFR AT MKE AND ENW FOR SEVERAL HOURS THIS
AFTERNOON...ALTHOUGH LOW CONFIDENCE ON CIGS DURING RAIN
SHOWERS...THEY MAY SLIP BACK INTO MVFR.
MVFR CIGS EXPECTED OVERNIGHT WITH THE POSSIBILITY FOR LIGHT SHOWERS.
&&
.PREV DISCUSSION... /ISSUED 331 AM CDT THU OCT 18 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH
CLASSIC CUT-OFF UPPER LOW WEATHER FOR THE AREA THIS PERIOD. THE
UPPER LOW WILL ONLY MOVE FROM SOUTHEAST MINNESOTA THIS MORNING TO
SOUTH CENTRAL WISCONSIN BY FRIDAY MORNING. A SERIES OF VORTICITY
MAXIMA ROTATING AROUND THE LOW WILL ENHANCE SHOWER CHANCES LATER
THIS MORNING AND OVERNIGHT. FOR THIS MORNING...A SHOT OF DRY AIR HAS
BEEN WORKING FROM SOUTHWEST TO NORTHEAST AND WILL LIKELY BRING DRY
CONDITIONS TO THE CWA BY 12Z THIS MORNING. THEN SHOWERS WILL
GRADUALLY SPREAD BACK IN FROM THE WEST BY 15Z AS THE NEXT SHORT WAVE
SWINGS AROUND THE UPPER LOW. COLD TEMPS ALOFT WITH STEEP LOW LEVEL
LAPSE RATES SHOULD MAKE SHOWER DEVELOPMENT AN EASY EFFORT. THE BEST
CHANCE FOR SHOWERS TODAY WILL BE ACROSS THE SOUTH HALF OF THE
CWA...SWINGING BACK UP ACROSS THE EASTERN CWA TONIGHT...FOLLOWING
THE OVERALL TRACK OF THE UPPER LEVEL FORCING AROUND THE CLOSED LOW.
TEMPS MUCH COOLER THAN YESTERDAY...AND COOLEST OUT WEST WHERE THE
RAIN WILL ARRIVE EARLIER THAN THE EAST.
FRIDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
STACKED LOW PRESSURE SYSTEM CENTERED AROUND THE WI/IL BORDER FRIDAY
MORNING WILL MOVE SLOWLY TO THE MI/IN BORDER BY FRIDAY EVENING. THE
LOW WILL BE WEAKENING...BUT SHOULD STILL BE ENOUGH LOW LEVEL
MOISTURE AND LIFT TO KEEP SHOWERS IN THE AREA. THUS KEPT HIGH CHANCE
TO LIKELY POPS GOING THROUGH THE DAY.
TEMPS WILL STRUGGLE INTO THE UPPER 40S MOST PLACES GIVEN THE
EXPECTED CLOUD COVER...PRECIP...AND COOLER AIRMASS WITH THE LOW.
CLOUDS SHOULD DECREASE FRIDAY NIGHT...THOUGH EXPECTING AT LEAST
SCATTERED CLOUD COVER TO KEEP LOWS FROM GETTING AS COOL AS
POSSIBLE GIVEN COOLER AIR ALOFT.
SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
TEMPERATURES SHOULD WARM TO NEAR NORMAL SATURDAY THEN A FEW DEGREES
ABOVE NORMAL SUNDAY AS UPPER RIDGING BUILDS INTO THE AREA. SHOULD BE
DRY THROUGH THE WEEKEND...THOUGH LINGERING LOW LEVEL MOISTURE AND
COOLER AIR ALOFT SHOULD ALLOW FOR SCATTERED TO BROKEN DIURNAL
CUMULUS SATURDAY. SHOULD SEE MORE SUNSHINE ON SUNDAY.
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
MODELS IN SOMEWHAT BETTER AGREEMENT FOR THE FIRST HALF OF NEXT
WEEK. OVERALL...LOOKS LIKE MILDER AIR WILL PERSIST IN THE
REGION...THOUGH ECMWF AND GFS GOING BACK AND FORTH WITH ARRIVAL OF
COOLER AIR BY MID WEEK. WENT WITH SHOWER AND STORM CHANCES THROUGH
WEDNESDAY DUE TO THE COMBINATION OF WARM AIR ADVECTION AND
MULTIPLE SHORTWAVES WITHIN THE FLOW.
AVIATION/12Z TAFS/...
A LARGE AND SLOW MOVING LOW PRESSURE SYSTEM WILL BRING MVFR
CONDITIONS TO THE AREA THROUGH MOST OF THE TAF PERIOD. VFR
CONDITIONS AROUND THE AREA EARLY THIS MORNING...WILL BE REPLACED BY
THE MVFR CIGS MOVING IN FROM THE WEST. THE COMBINATION OF COLD
TEMPS ALOFT...STEEP LOW LEVEL LAPSE RATES AND SHORT WAVE ENERGY
WRAPPING AROUND THE UPPER LOW...WILL BRING INCREASING CHANCES OF
SHOWERS THROUGH DAY...CONTINUING INTO TONIGHT.
MARINE...BREEZY SOUTHWEST WINDS ON THE SOUTH SIDE OF A LARGE LOW
PRESSURE SYSTEM LIFTING INTO NORTHERN WISCONSIN WILL REQUIRE AN
EXTENSION OF THE SMALL CRAFT ADVISORY INTO THIS EVENING. THE LOW
WILL BEGIN TO WEAKEN WITH THE WINDS AND WAVE DIMINISHING TONIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
FRIDAY THROUGH WEDNESDAY...DDV