Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/07/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1111 AM MST TUE MAR 5 2013
.UPDATE...
&&
.SHORT TERM...SHALLOW SNOW COVER IN MANY AREAS AND LIGHT WINDS
ARE RESTRAINING THE TEMPERATURE RISE TODAY ABOUT AS EXPECTED.
MINOR CHANGES TO HIGH TEMPERATURES...MAINLY COLDER IN THE VALLEYS
OF GRAND COUNTY.
&&
.AVIATION...VFR CONDITIONS THROUGH WEDNESDAY. LIGHT E-SE WINDS
THIS AFTERNOON WITH N-NE AT KBJC...KDEN COULD GO NE FOR A WHILE
BUT SHOULD BE LESS THAN 8 KNOTS IF IT DOES.
&&
.PREV DISCUSSION... /ISSUED 353 AM MST TUE MAR 5 2013/
SHORT TERM...AN UPPER LEVEL RIDGE WILL BUILD INTO THE RGN TODAY
WITH A DRY AIRMASS IN PLACE. SFC PTRN HAS A SFC ANTICLYCONE OVER
THE NERN PLAINS WHICH KEEPS WINDS NNW OVER THE FAR NERN CORNER
WHILE CLOSER TO THE FOOTHILLS LOW LVL WINDS ARE SELY. MEANWHILE
WITH SOME SNOW COVER AND SELY WINDS IT WILL BE INTERESTING TO SEE
HOW HIGH TEMPS GET THIS AFTN AS THERE ARE SOME WIDE RANGES BETWEEN
THE GUIDANCE NUMBERS. LATEST RAP AND NAM KEEP HIGHS IN THE 30S
FROM CENTRAL WELD INTO MORGAN AND ERN PORTIONS ADAMS AND ARAPAHOE
COUNTIES WITH HIGHS IN THE LOWER TO MID 40S IN THE WRN AND SRN
SUBURBS OF DENVER. MEANWHILE THE GFS AND HRRR ARE WARMER WITH
HIGHS IN THE 40S ACROSS ALL OF NERN CO WITH LOWER 50S OVER THE
WRN AND SRN SUBURBS OF DENVER. WITH SELY LOW LVL FLOW AT LOWER
LEVELS AND SOME LINGERING SNOW COVER WOULD HAVE TO BELIEVE HIGHS
WILL NOT BE AS WRM AS HRRR AND GFS SHOW SO WILL HAVE READINGS
MOSTLY IN THE 40 TO 45 DEGREE RANGE.
LONG TERM...THE REST OF THE WORK WEEK PROMISES TO BE DRY AND WARM
AS A STRONG UPPER LEVEL RIDGE BUILDS OVER THE STATE. THE RIDGE
AXIS IS EXPECTED TO MOVE EAST OF COLORADO BY WEDNESDAY AFTERNOON
WITH INCREASING SOUTHWESTERLY FLOW ALOFT SPREADING OVER THE STATE
THURSDAY AND FRIDAY. MID AND UPPER LEVEL MOISTURE WILL INCREASE
FROM THE WEST THROUGH THE DAY ON FRIDAY AS A POTENT UPPER LOW
DEVELOPS OVER CALIFORNIA. FOR THE PAST COUPLE DAYS THE ECMWF HAS
BEEN SHOWING THIS UPPER LOW EVENTUALLY MOVING TO THE FOUR CORNERS
REGION AND BRINGING THE POTENTIAL FOR SNOW TO THE STATE OVER THE
WEEKEND. OTHER MEDIUM AND LONG RANGE MODELS WERE SHOWING DIFFERENT
SOLUTIONS...BUT THE LATEST RUN OF THE LATEST RUN OF THE GFS IS NOW
BEGINNING TO COME IN LINE WITH THE ECMWF. YESTERDAY AFTERNOON/S
FORECAST PACKAGE ALREADY HAD SNOW LIKELY ACROSS OUR FORECAST AREA
FOR SATURDAY...AND NOW IS NOT THE TIME TO MAKE ANY CHANGES TO
THAT. WE WILL BE LOOKING AT SUCCESSIVE MODEL RUNS OVER THE NEXT
COUPLE DAYS TO ASSESS IF THE ECMWF MODEL CONTINUES TO BE THE MODEL
SOLUTION TO BASE THE FORECAST ON. IF THE GFS AND NAM MODELS FALL
IN LINE WITH THE ECMWF THEN A SIGNIFICANT SNOW EVENT COULD BE IN
STORE FOR THIS WEEKEND. STAY TUNED FOR OUR LATER FORECAST
PACKAGES. THE WEATHER FOR EARLY NEXT WEEK IS GOING TO DEPEND ON
HOW LONG THE SATURDAY UPPER LOW LINGERS OVER THE REGION. THE ECMWF
AND GFS HAVE VERY DIFFERENT IDEAS ABOUT THIS...SO WILL JUST STICK
WITH A DECREASING CHANCE OF SNOW ON MONDAY FOR NOW.
AVIATION...VFR THRU TONIGHT. LOOKS LIKE THERE WILL BE AN
SFC ANTICYCLONE CENTERED OVER THE NERN PLAINS WHICH WILL KEEP LOW
LVL WINDS SELY MUCH OF THE DAY WITH SPEEDS AROUND 10 KTS OR SO. BY
THIS EARLY EVENING WINDS MAY GRADUALLY BECOME MORE SLY AND THEN
STAY DRAINAGE OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....DANKERS
AVIATION/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
353 AM MST TUE MAR 5 2013
.SHORT TERM...AN UPPER LEVEL RIDGE WILL BUILD INTO THE RGN TODAY
WITH A DRY AIRMASS IN PLACE. SFC PTRN HAS A SFC ANTICLYCONE OVER
THE NERN PLAINS WHICH KEEPS WINDS NNW OVER THE FAR NERN CORNER
WHILE CLOSER TO THE FOOTHILLS LOW LVL WINDS ARE SELY. MEANWHILE
WITH SOME SNOW COVER AND SELY WINDS IT WILL BE INTERESTING TO SEE
HOW HIGH TEMPS GET THIS AFTN AS THERE ARE SOME WIDE RANGES BETWEEN
THE GUIDANCE NUMBERS. LATEST RAP AND NAM KEEP HIGHS IN THE 30S
FROM CENTRAL WELD INTO MORGAN AND ERN PORTIONS ADAMS AND ARAPAHOE
COUNTIES WITH HIGHS IN THE LOWER TO MID 40S IN THE WRN AND SRN
SUBURBS OF DENVER. MEANWHILE THE GFS AND HRRR ARE WARMER WITH
HIGHS IN THE 40S ACROSS ALL OF NERN CO WITH LOWER 50S OVER THE
WRN AND SRN SUBURBS OF DENVER. WITH SELY LOW LVL FLOW AT LOWER
LEVELS AND SOME LINGERING SNOW COVER WOULD HAVE TO BELIEVE HIGHS
WILL NOT BE AS WRM AS HRRR AND GFS SHOW SO WILL HAVE READINGS
MOSTLY IN THE 40 TO 45 DEGREE RANGE.
.LONG TERM...THE REST OF THE WORK WEEK PROMISES TO BE DRY AND WARM
AS A STRONG UPPER LEVEL RIDGE BUILDS OVER THE STATE. THE RIDGE
AXIS IS EXPECTED TO MOVE EAST OF COLORADO BY WEDNESDAY AFTERNOON
WITH INCREASING SOUTHWESTERLY FLOW ALOFT SPREADING OVER THE STATE
THURSDAY AND FRIDAY. MID AND UPPER LEVEL MOISTURE WILL INCREASE
FROM THE WEST THROUGH THE DAY ON FRIDAY AS A POTENT UPPER LOW
DEVELOPS OVER CALIFORNIA. FOR THE PAST COUPLE DAYS THE ECMWF HAS
BEEN SHOWING THIS UPPER LOW EVENTUALLY MOVING TO THE FOUR CORNERS
REGION AND BRINGING THE POTENTIAL FOR SNOW TO THE STATE OVER THE
WEEKEND. OTHER MEDIUM AND LONG RANGE MODELS WERE SHOWING DIFFERENT
SOLUTIONS...BUT THE LATEST RUN OF THE LATEST RUN OF THE GFS IS NOW
BEGINNING TO COME IN LINE WITH THE ECMWF. YESTERDAY AFTERNOON/S
FORECAST PACKAGE ALREADY HAD SNOW LIKELY ACROSS OUR FORECAST AREA
FOR SATURDAY...AND NOW IS NOT THE TIME TO MAKE ANY CHANGES TO
THAT. WE WILL BE LOOKING AT SUCCESSIVE MODEL RUNS OVER THE NEXT
COUPLE DAYS TO ASSESS IF THE ECMWF MODEL CONTINUES TO BE THE MODEL
SOLUTION TO BASE THE FORECAST ON. IF THE GFS AND NAM MODELS FALL
IN LINE WITH THE ECMWF THEN A SIGNIFICANT SNOW EVENT COULD BE IN
STORE FOR THIS WEEKEND. STAY TUNED FOR OUR LATER FORECAST
PACKAGES. THE WEATHER FOR EARLY NEXT WEEK IS GOING TO DEPEND ON
HOW LONG THE SATURDAY UPPER LOW LINGERS OVER THE REGION. THE ECMWF
AND GFS HAVE VERY DIFFERENT IDEAS ABOUT THIS...SO WILL JUST STICK
WITH A DECREASING CHANCE OF SNOW ON MONDAY FOR NOW.
&&
.AVIATION...VFR THRU TONIGHT. LOOKS LIKE THERE WILL BE AN
SFC ANTICYCLONE CENTERED OVER THE NERN PLAINS WHICH WILL KEEP LOW
LVL WINDS SELY MUCH OF THE DAY WITH SPEEDS AROUND 10 KTS OR SO. BY
THIS EARLY EVENING WINDS MAY GRADUALLY BECOME MORE SLY AND THEN
STAY DRAINAGE OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....DANKERS
AVIATION...RPK
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW YORK NY
1013 PM EST WED MAR 6 2013
.SYNOPSIS...
A NOR-EASTER WILL AFFECT THE REGION THROUGH FRIDAY. HIGH
PRESSURE THEN BUILDS FROM THE WEST THIS WEEKEND. ANOTHER STORM
SYSTEM APPROACHES THE REGION EARLY NEXT WEEK AND IMPACTS THE AREA
BY MID WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EXPECT 993 HPA LOW OFF THE DELMARVA PENINSULA TO SLOWLY MOVE ENE
TONIGHT...AND STRENGTHEN SLIGHTLY...AS IT MOVES WITH CUTOFF LOW
ABOVE IT. OPERATIONAL SYNOPTIC SCALE MODELS SEEM TO BE UNDER
ESTIMATING STRENGTH OF RIDGING TO THE N/NE OF THE LOW AND HENCE
ARE TOO FAST IN MOVING PRECIPITATION INTO THE TRI-STATE.
ONLY MODELS WHICH SEEM TO HAVE ANY GRASP ON CURRENT SITUATION ARE
THE HRRR AND RUC - AND THIS UPDATE REFLECTS THIS. PRECIPITATION IS
ONGOING ACROSS THE S 1/3 OF THE CWA AND SHOULD CONTINUE TO PUSH N
THROUGH MIDNIGHT. AS PRECIPITATION CONTINUES TO EXPAND - KOKX 00Z
SOUNDING SHOWS THAT SHOULD QUICKLY WET BULB TO AT OR BELOW
FREEZING IN ENOUGH OF THE COLUMN THAT PRECIPITATION SHOULD CHANGE
TO ALL SNOW WITHIN AN HOUR OR SO OF STARTING. ALREADY HAVING
REPORTS OF PRECIPITATION CHANGING TO ALL SNOW WITH TEMPERATURES IN
THE UPPER 30S. SURFACE DEWPOINTS HAVE ALSO BEEN FALLING THROUGH
THE EVENING - SO APPEARS THAT AT LEAST NORTHERN ZONES SHOULD HAVE
TEMPERATURES FALL TO AT OR BELOW FREEZING OVERNIGHT WITH SOUTHERN
ZONES AT OR JUST ABOVE.
GIVEN THE WARM TEMPERATURES AT WHICH CHANGEOVER IS
OCCURRING...EXPECT ANY INITIAL ACCUMULATIONS OVER THE NEXT FEW
HOURS TO BE LIMITED TO MAINLY GRASSY SURFACES.
SO OVERNIGHT...EXPECTING ONLY AN INCH OR TWO OF SNOWFALL. WILL LEAVE
THE INHERITED WINTER WEATHER ADVISORY AS IS FOR TONIGHT AND
STRETCH IT OUT IN TIME...BUT WILL STRESS THAT MORE OF THE
ACCUMULATION WILL OCCUR AFTER TONIGHT. FOR NEW LONDON COUNTY AND
EASTERN LONG ISLAND...WILL GO WITH A START TIME LATE TONIGHT. THE
WINTER STORM WATCH FOR THESE AREAS WILL BE CANCELLED AS IT APPEARS
THAT WARNING CRITERIA WILL NOT BE MET. FOR THE NW ZONES...WILL
START THE WINTER WEATHER ADVISORY LATER IN TIME. MORE ON THIS IN
THE SHORT TERM SECTION BELOW.
THE WIND ADVISORY WILL REMAIN AS POSTED...WITH THE ADDITION OF ALL
OF NEW LONDON COUNTY. EXPECTING GUSTS UP TO 50-55 MPH OVERNIGHT IN
THE ADVISORY AREA AND 35-45 MPH ELSEWHERE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE STORM BEGINS TO TURN NE...BUT STILL WELL OUT TO SEA. NAM IS
ALONE IN BRINGING A WARM NOSE ALOFT DURING THE AFTERNOON/NIGHTTIME
HOURS. PREFER THE COLDER THERMAL PROFILES ALOFT OF GFS AND ECMWF.
FOR SURFACE TEMPS...PREFERRED SOMETHING CLOSER TO THE COLDER NAM MOS
GUIDANCE. DAYTIME TEMPS THEREFORE MAINLY IN THE MID TO UPPER 30S.
THERE COULD BE SOME RAIN MIXED IN AT TIMES...BUT THINKING IS THAT
THE ENTIRE AREA SEES A WET SNOW THROUGH THE DAY. GUSTS UP TO 50 MPH
ARE STILL EXPECTED THROUGH THE AFTERNOON ACROSS THE COASTAL
ZONES...SO THE WIND ADVISORY WILL BE MAINTAINED THROUGH THIS TIME.
A STRONG SHORTWAVE THEN ARRIVES FROM THE NW DURING THURSDAY NIGHT
AND INTERACTS WITH AN INVERTED SURFACE TROUGH. THIS WILL KEEP A
LIKELIHOOD OF SNOWFALL ACROSS THE AREA THROUGH THE NIGHT. PRECIP
TYPE THROUGH THE NIGHT IS EXPECTED TO BE ALL SNOW. BY FRIDAY
MORNING...SNOWFALL AMOUNTS OF MOSTLY 3 TO 6 INCHES EXPECTED...WITH
THE HIGHER AMOUNTS GENERALLY OVER CT. HAVE DECIDED TO GO WITH A
WINTER WEATHER ADVISORY FOR THE NW ZONES STARTING THURSDAY NIGHT AND
GOING THROUGH FRIDAY MORNING AS THIS WILL BE THE PERIOD OF MOST OF
THE SNOWFALL FOR THIS EVENT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
INITIALLY...EXPECT A STACKED LOW WELL SOUTH AND EAST OF THE
BENCHMARK EARLY FRIDAY...WITH SHORTWAVE TROUGH TO OUR SOUTH
EVENTUALLY PIVOTING AROUND THE BASE OF THE AFOREMENTIONED LOW LATER
FRIDAY. MODELS IN AGREEMENT WITH REGARD TO LARGE RIDGE BUILDING IN
THIS WEEKEND. DIFFERENCES ARISE WITH NORTHERN STREAM SHORTWAVE
DIGGING ACROSS CANADA...FLATTENING THE RIDGE LATE THIS WEEKEND INTO
EARLY NEXT WEEK. THEN UPSTREAM MID WEST TROUGH APPROACHES EARLY NEXT
WEEK...MONDAY AND TUESDAY. AGAIN...MODELS ARE SLIGHTLY DIFFERENT ON
SUBTLE DETAILS...BUT ALL DO INDICATE THAT THIS TROUGH WILL IMPACT
THE AREA IN SOME FORM LATER MONDAY INTO TUESDAY. LINGERING TROUGH
SLOWLY EXITS WEDNESDAY.
AT THE SURFACE...TIGHT NORTHERLY PRESSURE GRADIENT PERSISTS ON
FRIDAY AS AREA REMAINS BETWEEN DEEP LOW TO THE EAST AND BUILDING
HIGH PRESSURE TO THE WEST. THE HIGH LOOKS TO BUILD IN LATER SATURDAY
THROUGH SUNDAY MORNING...THEN PASSES EAST. A WEAK FRONTAL BOUNDARY
APPROACHES FROM THE NORTH...ASSOCIATED WITH NORTHERN STREAM
MID/UPPER TROUGH...BUT MAIN FRONT AHEAD OF MIDWEST TROUGH DOES NOT
MOVE THROUGH UNTIL SOME TIME LATE MONDAY NIGHT OR TUESDAY. A GENERAL
NW FLOW PREVAILS BEHIND THIS FRONT TUESDAY NIGHT INTO
WEDNESDAY...WITH PERHAPS A WEAK SFC TROUGH IN THE VICINITY WHICH IS
ASSOCIATED WITH LINGERING UPPER TROUGH WEDNESDAY.
AS FOR SENSIBLE WEATHER...WILL DISCARD NAM SOLUTION FOR WARM NOSE
ALOFT (H9-H7 HPA) PER FCST SOUNDINGS AND MAPS...WITH GFS AND ECMWF
MUCH COLDER EARLY FRIDAY. WILL MAINTAIN SNOW AS WEATHER TYPE INTO
FRIDAY...THEN PRECIP TAPERS OFF LATER FRIDAY THROUGH MUCH OF THE
WEEKEND...MAYBE AS A RAIN/SNOW MIX. SOME LIGHT PRECIP POSSIBLE SUNDAY
NIGHT...WITH THE BULK OF THE PRECIP EXPECTED LATE MONDAY INTO
TUESDAY WITH THE FRONT. P-TYPE WILL BE MAINLY RAIN IN WAA PATTERN.
COLDER AIR MOVES IN BEHIND THE FRONT...WITH SNOW SHOWERS POSSIBLE
TUE NIGHT AND WED.
TEMPS WILL REMAIN BELOW NORMAL FRIDAY...THEN WILL WARM TO ABOVE
NORMAL READINGS THIS WEEKEND...THANKS TO RIDGE.
WARMER THEN NORMAL TEMPS CONTINUE MONDAY AND TUESDAY...WITH A RETURN
TO BELOW NORMAL BEHIND THE FRONT TUE NIGHT AND WED. HPC/MEX/ECMWF
BLEND USED.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
SIGNIFICANT AVIATION WEATHER IMPACTS CONTINUE THROUGH FRIDAY WITH
PROLONGED STRONG WINDS...LIGHT RAIN AND SNOW WITH PERIODS OF IFR AS
A NOR-EASTER JUST OFF THE DELMARVA PENINSULA SLOWLY TRACKS EAST OVER
THE ATLANTIC.
TOTAL SNOW FORECAST THROUGH FRIDAY RANGES FROM 3 TO 6 INCHES WITH
MOST ACCUMULATIONS OCCURRING AT NIGHT WITH 1 TO 3 INCHES POSSIBLE
TONIGHT AND THEN ANOTHER 2 TO 4 INCHES POSSIBLE THURSDAY NIGHT. THIS
FORECAST COULD BE A BIT ON THE HIGH SIDE AS TEMPERATURES STAY AT OR
JUST ABOVE FREEZING. RUNWAY ACCUMULATIONS TONIGHT WILL LIKELY
AVERAGE A SLUSHY 1 OR 2 INCHES. NOTE THAT LITTLE OR NO RUNWAY SNOW
ACCUMULATION IS EXPECTED DURING THE DAY ON THURSDAY.
LIGHT RAIN NEAR THE COAST WILL QUICKLY MIX WITH AND CHANGE TO SNOW
BY 04Z. ACROSS THE INTERIOR...LIGHT SNOW WILL DEVELOP BY MIDNIGHT
AND CONTINUE THROUGH THURSDAY MORNING. GENERALLY MVFR CONDITIONS UNTIL
SNOW DEVELOPS...THEN CONDITIONS DROP TO IFR.
LOW CONFIDENCE FORECAST ON THURSDAY. PERIODS OF SNOW...MIXING WITH
RAIN IN THE AFTERNOON...WILL KEEP CIGS/VSBYS AT IFR FROM TIME TO
TIME...BUT TIMING IS UNCERTAIN. THERE MAY BE A PROLONGED PERIOD OF
VFR CONDITIONS DURING THE MIDDLE OF THE DAY IN BETWEEN BOUTS OF PRECIP.
NORTHEAST WINDS 20-25 KT WITH 35-40 KT GUSTS TONIGHT...BACKING TO
THE NORTH BY THURSDAY MORNING AND DIMINISHING TO 15-20 KT WITH 20-30
KT GUSTS.
STRONG LLWS CONCERNS THROUGH THURSDAY MORNING WITH 50-55 KT WINDS AT
2000 FT AND BELOW.
OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.THU NGT-FRI...N G35KT. IFR WITH LIGHT SNOW ENDING FRI MORNING.
LIGHT OVERNIGHT SNOW ACCUMULATIONS LIKELY...HIGHEST EAST.
.FRI NGT...BECOMING VFR.
.SAT-SUN...VFR.
.MON...VFR...INCREASING S WND LATE DAY.
&&
.MARINE...
MINOR CHANGES TO WIND/WAVE GRIDS TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK - THOUGH WILL
HAVE TO MONITOR WINDS AROUND THE S SHORE BAYS AS ARE SOME
INDICATIONS THAT AN UPGRADE TO A STORM WARNING MIGHT BE IN ORDER
THERE.
GALE WARNINGS REMAIN POSTED FOR THE WESTERN SOUND...NY
HARBOR...AND THE SOUTH SHORE BAYS. STORM WARNINGS REMAIN
ELSEWHERE. THESE WARNINGS CONTINUE THROUGH THURSDAY AFTERNOON.
GALES WILL STILL BE LIKELY DURING THURSDAY NIGHT EVEN THOUGH
WINDS WILL SUBSIDE SOMEWHAT THROUGH THE NIGHT.
A TIGHT PRESSURE GRADIENT ON FRIDAY AS THE WATERS REMAIN BETWEEN
DEPARTING DEEP LOW PRESSURE TO THE EAST AND BUILDING HIGH PRESSURE
TO THE WEST. GALE FORCE WINDS...APPROACHING STORM FORCE FRIDAY OVER
THE EASTERN WATERS...WITH GALES ELSEWHERE WILL SLOWLY IMPROVE FRIDAY
NIGHT AND SATURDAY AS THE HIGH BUILDS. IN FACT...MUCH LIGHTER WINDS
CAN BE EXPECTED LATE SATURDAY INTO SUNDAY AS THE HIGH BUILDS OVER
THE WATERS.
A RETURN FLOW IS FORECAST BY LATE SUNDAY NIGHT INTO MONDAY AS THE
HIGH MOVES EAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST.
VERY ROUGH SEAS FRIDAY WILL SLOWLY SUBSIDE FRIDAY NIGHT INTO
SATURDAY. SEAS REMAIN 3 TO 5 FT OVER THE OCEAN WATERS THROUGH MUCH
OF THE WEEKEND AND INTO MONDAY. THE SHELTERED WATERS WILL BE MUCH
MORE TRANQUIL ONCE THE WINDS DIMINISH THIS WEEKEND.
&&
.HYDROLOGY...
TOTAL LIQUID QPF THROUGH FRI IS CURRENTLY EXPECTED TO BE AROUND 2/3
OF AN INCH ACROSS THE LOWER HUDSON VALLEY...RANGING TO AROUND 1 1/2
INCHES ACROSS EASTERN CT/LI. HYDRO RELATED ISSUES ARE NOT
ANTICIPATED AT THIS TIME WITH THE PRECIPITATION OCCURRING OVER A
RELATIVELY LONG PERIOD OF TIME AND MAINLY FROZEN.
ONCE PRECIP TAPERS OFF LATER FRIDAY...THE NEXT CHANCE FOR
PRECIPITATION...GENERALLY UNDER A HALF AN INCH...WILL OCCUR EARLY
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
WITH A TRACK OF LOW PRESSURE WELL SE OF THE REGION...AND EARLY
BACKING OF FLOW TO THE N/NE...WATERS LEVELS ONLY ROSE TO LOW END
OF EXPECTED RANGES THIS AFTERNOON/EVENING.
DESPITE LARGE SWELLS AFFECTING THE COAST OVERNIGHT INTO THURSDAY
MORNING AND HIGHER ASTRONOMICAL TIDES...NORTHERLY FLOW SHOULD
LIMIT SURGE TO 2 TO 3 FT. EXPECTATION CONTINUES FOR WIDESPREAD
MINOR COASTAL FLOODING FOR MOST OF THE TRI-STATE COASTLINE...WITH
MODERATE COASTAL FLOODING ALONG THE SOUTH SHORE BAYS...OCEAN
FACING COASTLINE...AND TWIN FORKS OF LI...WHERE TIDAL DRAINAGE
WILL BE INHIBITED BY LARGE SWELLS.
MODERATE TO MAJOR BEACH EROSION IS EXPECTED FOR OCEAN FACING
BEACHES AND TWIN FORKS OF LI THROUGH THURSDAY...WITH BREAKERS OF
10 TO 15 FT. THESE WAVES WILL ALSO ENHANCE INUNDATION AND CAUSE
LOCALIZED WASHOVERS AND DAMAGE TO COASTAL STRUCTURES.
THEREAFTER...THE RESIDUAL EASTERLY SWELLS WILL POSE A THREAT FOR
WIDESPREAD MINOR COASTAL FLOODING ISSUES DURING THE TIMES OF THE
MORNING HIGH TIDES THROUGH FRI. THE SOUTH SHORE BAYS...OCEAN
FACING COASTLINE...AND TWIN FORKS OF LI...MAY SEE LOCALIZED MINOR
COASTAL FLOODING DURING THE LOWER AFTERNOON/EVENING HIGH TIDES AS
WELL DUE TO RESTRICTED TIDAL DRAINAGE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR CTZ008-012.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR CTZ008>012.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR CTZ005>007-
009>011.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
CTZ009>012.
NY...COASTAL FLOOD WARNING FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ079-081.
WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR NYZ079-081.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NYZ071>075-078>081-
176>179.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NYZ067-068.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NYZ069>075-
078-080-176>179.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NYZ072-074-075-178.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ071-073-078-176-177.
COASTAL FLOOD WARNING FROM 2 AM TO 7 AM EST THURSDAY FOR
NYZ080-179.
NJ...WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NJZ006.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NJZ002-004-103.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NJZ006-
104>108.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NJZ006-106-108.
MARINE...GALE WARNING UNTIL 6 PM EST FRIDAY FOR ANZ335-338-345.
STORM WARNING UNTIL 6 PM EST THURSDAY FOR ANZ330-340-350-353-
355.
&&
$$
SYNOPSIS...JC
NEAR TERM...MALOIT/JC
SHORT TERM...JC
LONG TERM...PW
AVIATION...MPS
MARINE...MALOIT/NV/PW
HYDROLOGY...JC/PW
TIDES/COASTAL FLOODING...NV
AREA FORECAST DISCUSSION
NWS NEW YORK NY
958 PM EST WED MAR 6 2013
.SYNOPSIS...
A NOR-EASTER WILL AFFECT THE REGION THROUGH FRIDAY. HIGH
PRESSURE THEN BUILDS FROM THE WEST THIS WEEKEND. ANOTHER STORM
SYSTEM APPROACHES THE REGION EARLY NEXT WEEK AND IMPACTS THE AREA
BY MID WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EXPECT 993 HPA LOW OFF THE DELMARVA PENINSULA TO SLOWLY MOVE ENE
TONIGHT...AND STRENGTHEN SLIGHTLY...AS IT MOVES WITH CUTOFF LOW
ABOVE IT. OPERATIONAL SYNOPTIC SCALE MODELS SEEM TO BE UNDER
ESTIMATING STRENGTH OF RIDGING TO THE N/NE OF THE LOW AND HENCE
ARE TOO FAST IN MOVING PRECIPITATION INTO THE TRI-STATE.
ONLY MODELS WHICH SEEM TO HAVE ANY GRASP ON CURRENT SITUATION ARE
THE HRRR AND RUC - AND THIS UPDATE REFLECTS THIS. PRECIPITATION IS
ONGOING ACROSS THE S 1/3 OF THE CWA AND SHOULD CONTINUE TO PUSH N
THROUGH MIDNIGHT. AS PRECIPITATION CONTINUES TO EXPAND - KOKX 00Z
SOUNDING SHOWS THAT SHOULD QUICKLY WET BULB TO AT OR BELOW
FREEZING IN ENOUGH OF THE COLUMN THAT PRECIPITATION SHOULD CHANGE
TO ALL SNOW WITHIN AN HOUR OR SO OF STARTING. ALREADY HAVING
REPORTS OF PRECIPITATION CHANGING TO ALL SNOW WITH TEMPERATURES IN
THE UPPER 30S. SURFACE DEWPOINTS HAVE ALSO BEEN FALLING THROUGH
THE EVENING - SO APPEARS THAT AT LEAST NORTHERN ZONES SHOULD HAVE
TEMPERATURES FALL TO AT OR BELOW FREEZING OVERNIGHT WITH SOUTHERN
ZONES AT OR JUST ABOVE.
SO THROUGH TONIGHT...EXPECTING ONLY AN INCH OR TWO OF SNOWFALL. WILL
LEAVE THE INHERITED WINTER WEATHER ADVISORY AS IS FOR TONIGHT AND
STRETCH IT OUT IN TIME...BUT WILL STRESS THAT MORE OF THE
ACCUMULATION WILL OCCUR AFTER TONIGHT. FOR NEW LONDON COUNTY AND
EASTERN LONG ISLAND...WILL GO WITH A START TIME LATE TONIGHT. THE
WINTER STORM WATCH FOR THESE AREAS WILL BE CANCELLED AS IT APPEARS
THAT WARNING CRITERIA WILL NOT BE MET. FOR THE NW ZONES...WILL
START THE WINTER WEATHER ADVISORY LATER IN TIME. MORE ON THIS IN
THE SHORT TERM SECTION BELOW.
THE WIND ADVISORY WILL REMAIN AS POSTED...WITH THE ADDITION OF ALL
OF NEW LONDON COUNTY. EXPECTING GUSTS UP TO 50-55 MPH OVERNIGHT IN
THE ADVIOSRY AREA AND 35-45 MPH ELSEWHERE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE STORM BEGINS TO TURN NE...BUT STILL WELL OUT TO SEA. NAM IS
ALONE IN BRINGING A WARM NOSE ALOFT DURING THE AFTERNOON/NIGHTTIME
HOURS. PREFER THE COLDER THERMAL PROFILES ALOFT OF GFS AND ECMWF.
FOR SURFACE TEMPS...PREFERRED SOMETHING CLOSER TO THE COLDER NAM MOS
GUIDANCE. DAYTIME TEMPS THEREFORE MAINLY IN THE MID TO UPPER 30S.
THERE COULD BE SOME RAIN MIXED IN AT TIMES...BUT THINKING IS THAT
THE ENTIRE AREA SEES A WET SNOW THROUGH THE DAY. GUSTS UP TO 50 MPH
ARE STILL EXPECTED THROUGH THE AFTERNOON ACROSS THE COASTAL
ZONES...SO THE WIND ADVISORY WILL BE MAINTAINED THROUGH THIS TIME.
A STRONG SHORTWAVE THEN ARRIVES FROM THE NW DURING THURSDAY NIGHT
AND INTERACTS WITH AN INVERTED SURFACE TROUGH. THIS WILL KEEP A
LIKELIHOOD OF SNOWFALL ACROSS THE AREA THROUGH THE NIGHT. PRECIP
TYPE THROUGH THE NIGHT IS EXPECTED TO BE ALL SNOW. BY FRIDAY
MORNING...SNOWFALL AMOUNTS OF MOSTLY 3 TO 6 INCHES EXPECTED...WITH
THE HIGHER AMOUNTS GENERALLY OVER CT. HAVE DECIDED TO GO WITH A
WINTER WEATHER ADVISORY FOR THE NW ZONES STARTING THURSDAY NIGHT AND
GOING THROUGH FRIDAY MORNING AS THIS WILL BE THE PERIOD OF MOST OF
THE SNOWFALL FOR THIS EVENT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
INITIALLY...EXPECT A STACKED LOW WELL SOUTH AND EAST OF THE
BENCHMARK EARLY FRIDAY...WITH SHORTWAVE TROUGH TO OUR SOUTH
EVENTUALLY PIVOTING AROUND THE BASE OF THE AFOREMENTIONED LOW LATER
FRIDAY. MODELS IN AGREEMENT WITH REGARD TO LARGE RIDGE BUILDING IN
THIS WEEKEND. DIFFERENCES ARISE WITH NORTHERN STREAM SHORTWAVE
DIGGING ACROSS CANADA...FLATTENING THE RIDGE LATE THIS WEEKEND INTO
EARLY NEXT WEEK. THEN UPSTREAM MID WEST TROUGH APPROACHES EARLY NEXT
WEEK...MONDAY AND TUESDAY. AGAIN...MODELS ARE SLIGHTLY DIFFERENT ON
SUBTLE DETAILS...BUT ALL DO INDICATE THAT THIS TROUGH WILL IMPACT
THE AREA IN SOME FORM LATER MONDAY INTO TUESDAY. LINGERING TROUGH
SLOWLY EXITS WEDNESDAY.
AT THE SURFACE...TIGHT NORTHERLY PRESSURE GRADIENT PERSISTS ON
FRIDAY AS AREA REMAINS BETWEEN DEEP LOW TO THE EAST AND BUILDING
HIGH PRESSURE TO THE WEST. THE HIGH LOOKS TO BUILD IN LATER SATURDAY
THROUGH SUNDAY MORNING...THEN PASSES EAST. A WEAK FRONTAL BOUNDARY
APPROACHES FROM THE NORTH...ASSOCIATED WITH NORTHERN STREAM
MID/UPPER TROUGH...BUT MAIN FRONT AHEAD OF MIDWEST TROUGH DOES NOT
MOVE THROUGH UNTIL SOME TIME LATE MONDAY NIGHT OR TUESDAY. A GENERAL
NW FLOW PREVAILS BEHIND THIS FRONT TUESDAY NIGHT INTO
WEDNESDAY...WITH PERHAPS A WEAK SFC TROUGH IN THE VICINITY WHICH IS
ASSOCIATED WITH LINGERING UPPER TROUGH WEDNESDAY.
AS FOR SENSIBLE WEATHER...WILL DISCARD NAM SOLUTION FOR WARM NOSE
ALOFT (H9-H7 HPA) PER FCST SOUNDINGS AND MAPS...WITH GFS AND ECMWF
MUCH COLDER EARLY FRIDAY. WILL MAINTAIN SNOW AS WEATHER TYPE INTO
FRIDAY...THEN PRECIP TAPERS OFF LATER FRIDAY THROUGH MUCH OF THE
WEEKEND...MAYBE AS A RAIN/SNOW MIX. SOME LIGHT PRECIP POSSIBLE SUNDAY
NIGHT...WITH THE BULK OF THE PRECIP EXPECTED LATE MONDAY INTO
TUESDAY WITH THE FRONT. P-TYPE WILL BE MAINLY RAIN IN WAA PATTERN.
COLDER AIR MOVES IN BEHIND THE FRONT...WITH SNOW SHOWERS POSSIBLE
TUE NIGHT AND WED.
TEMPS WILL REMAIN BELOW NORMAL FRIDAY...THEN WILL WARM TO ABOVE
NORMAL READINGS THIS WEEKEND...THANKS TO RIDGE.
WARMER THEN NORMAL TEMPS CONTINUE MONDAY AND TUESDAY...WITH A RETURN
TO BELOW NORMAL BEHIND THE FRONT TUE NIGHT AND WED. HPC/MEX/ECMWF
BLEND USED.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
SIGNIFICANT AVIATION WEATHER IMPACTS CONTINUE THROUGH FRIDAY WITH
PROLONGED STRONG WINDS...LIGHT RAIN AND SNOW WITH PERIODS OF IFR AS
A NOR-EASTER JUST OFF THE DELMARVA PENINSULA SLOWLY TRACKS EAST OVER
THE ATLANTIC.
TOTAL SNOW FORECAST THROUGH FRIDAY RANGES FROM 3 TO 6 INCHES WITH
MOST ACCUMULATIONS OCCURRING AT NIGHT WITH 1 TO 3 INCHES POSSIBLE
TONIGHT AND THEN ANOTHER 2 TO 4 INCHES POSSIBLE THURSDAY NIGHT. THIS
FORECAST COULD BE A BIT ON THE HIGH SIDE AS TEMPERATURES STAY AT OR
JUST ABOVE FREEZING. RUNWAY ACCUMULATIONS TONIGHT WILL LIKELY
AVERAGE A SLUSHY 1 OR 2 INCHES. NOTE THAT LITTLE OR NO RUNWAY SNOW
ACCUMULATION IS EXPECTED DURING THE DAY ON THURSDAY.
LIGHT RAIN NEAR THE COAST WILL QUICKLY MIX WITH AND CHANGE TO SNOW
BY 04Z. ACROSS THE INTERIOR...LIGHT SNOW WILL DEVELOP BY MIDNIGHT
AND CONTINUE THROUGH THURSDAY MORNING. GENERALLY MVFR CONDITIONS UNTIL
SNOW DEVELOPS...THEN CONDITIONS DROP TO IFR.
LOW CONFIDENCE FORECAST ON THURSDAY. PERIODS OF SNOW...MIXING WITH
RAIN IN THE AFTERNOON...WILL KEEP CIGS/VSBYS AT IFR FROM TIME TO
TIME...BUT TIMING IS UNCERTAIN. THERE MAY BE A PROLONGED PERIOD OF
VFR CONDITIONS DURING THE MIDDLE OF THE DAY IN BETWEEN BOUTS OF PRECIP.
NORTHEAST WINDS 20-25 KT WITH 35-40 KT GUSTS TONIGHT...BACKING TO
THE NORTH BY THURSDAY MORNING AND DIMINISHING TO 15-20 KT WITH 20-30
KT GUSTS.
STRONG LLWS CONCERNS THROUGH THURSDAY MORNING WITH 50-55 KT WINDS AT
2000 FT AND BELOW.
OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.THU NGT-FRI...N G35KT. IFR WITH LIGHT SNOW ENDING FRI MORNING.
LIGHT OVERNIGHT SNOW ACCUMULATIONS LIKELY...HIGHEST EAST.
.FRI NGT...BECOMING VFR.
.SAT-SUN...VFR.
.MON...VFR...INCREASING S WND LATE DAY.
&&
.MARINE...
MINOR CHANGES TO WIND/WAVE GRIDS TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK - THOUGH WILL
HAVE TO MONITOR WINDS AROUND THE S SHORE BAYS AS ARE SOME
INDICATIONS THAT AN UPGRADE TO A STORM WARNING MIGHT BE IN ORDER
THERE.
GALE WARNINGS REMAIN POSTED FOR THE WESTERN SOUND...NY
HARBOR...AND THE SOUTH SHORE BAYS. STORM WARNINGS REMAIN
ELSEWHERE. THESE WARNINGS CONTINUE THROUGH THURSDAY AFTERNOON.
GALES WILL STILL BE LIKELY DURING THURSDAY NIGHT EVEN THOUGH
WINDS WILL SUBSIDE SOMEWHAT THROUGH THE NIGHT.
A TIGHT PRESSURE GRADIENT ON FRIDAY AS THE WATERS REMAIN BETWEEN
DEPARTING DEEP LOW PRESSURE TO THE EAST AND BUILDING HIGH PRESSURE
TO THE WEST. GALE FORCE WINDS...APPROACHING STORM FORCE FRIDAY OVER
THE EASTERN WATERS...WITH GALES ELSEWHERE WILL SLOWLY IMPROVE FRIDAY
NIGHT AND SATURDAY AS THE HIGH BUILDS. IN FACT...MUCH LIGHTER WINDS
CAN BE EXPECTED LATE SATURDAY INTO SUNDAY AS THE HIGH BUILDS OVER
THE WATERS.
A RETURN FLOW IS FORECAST BY LATE SUNDAY NIGHT INTO MONDAY AS THE
HIGH MOVES EAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST.
VERY ROUGH SEAS FRIDAY WILL SLOWLY SUBSIDE FRIDAY NIGHT INTO
SATURDAY. SEAS REMAIN 3 TO 5 FT OVER THE OCEAN WATERS THROUGH MUCH
OF THE WEEKEND AND INTO MONDAY. THE SHELTERED WATERS WILL BE MUCH
MORE TRANQUIL ONCE THE WINDS DIMINISH THIS WEEKEND.
&&
.HYDROLOGY...
TOTAL LIQUID QPF THROUGH FRI IS CURRENTLY EXPECTED TO BE AROUND 2/3
OF AN INCH ACROSS THE LOWER HUDSON VALLEY...RANGING TO AROUND 1 1/2
INCHES ACROSS EASTERN CT/LI. HYDRO RELATED ISSUES ARE NOT
ANTICIPATED AT THIS TIME WITH THE PRECIPITATION OCCURRING OVER A
RELATIVELY LONG PERIOD OF TIME AND MAINLY FROZEN.
ONCE PRECIP TAPERS OFF LATER FRIDAY...THE NEXT CHANCE FOR
PRECIPITATION...GENERALLY UNDER A HALF AN INCH...WILL OCCUR EARLY
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
WITH A TRACK OF LOW PRESSURE WELL SE OF THE REGION...AND EARLY
BACKING OF FLOW TO THE N/NE...WATERS LEVELS ONLY ROSE TO LOW END
OF EXPECTED RANGES THIS AFTERNOON/EVENING.
DESPITE LARGE SWELLS AFFECTING THE COAST OVERNIGHT INTO THURSDAY
MORNING AND HIGHER ASTRONOMICAL TIDES...NORTHERLY FLOW SHOULD
LIMIT SURGE TO 2 TO 3 FT. EXPECTATION CONTINUES FOR WIDESPREAD
MINOR COASTAL FLOODING FOR MOST OF THE TRI-STATE COASTLINE...WITH
MODERATE COASTAL FLOODING ALONG THE SOUTH SHORE BAYS...OCEAN
FACING COASTLINE...AND TWIN FORKS OF LI...WHERE TIDAL DRAINAGE
WILL BE INHIBITED BY LARGE SWELLS.
MODERATE TO MAJOR BEACH EROSION IS EXPECTED FOR OCEAN FACING
BEACHES AND TWIN FORKS OF LI THROUGH THURSDAY...WITH BREAKERS OF
10 TO 15 FT. THESE WAVES WILL ALSO ENHANCE INUNDATION AND CAUSE
LOCALIZED WASHOVERS AND DAMAGE TO COASTAL STRUCTURES.
THEREAFTER...THE RESIDUAL EASTERLY SWELLS WILL POSE A THREAT FOR
WIDESPREAD MINOR COASTAL FLOODING ISSUES DURING THE TIMES OF THE
MORNING HIGH TIDES THROUGH FRI. THE SOUTH SHORE BAYS...OCEAN
FACING COASTLINE...AND TWIN FORKS OF LI...MAY SEE LOCALIZED MINOR
COASTAL FLOODING DURING THE LOWER AFTERNOON/EVENING HIGH TIDES AS
WELL DUE TO RESTRICTED TIDAL DRAINAGE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR CTZ008-012.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR CTZ008>012.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR CTZ005>007-
009>011.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
CTZ009>012.
NY...COASTAL FLOOD WARNING FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ079-081.
WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR NYZ079-081.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NYZ071>075-078>081-
176>179.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NYZ067-068.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NYZ069>075-
078-080-176>179.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NYZ072-074-075-178.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ071-073-078-176-177.
COASTAL FLOOD WARNING FROM 2 AM TO 7 AM EST THURSDAY FOR
NYZ080-179.
NJ...WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NJZ006.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NJZ002-004-103.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NJZ006-
104>108.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NJZ006-106-108.
MARINE...GALE WARNING UNTIL 6 PM EST FRIDAY FOR ANZ335-338-345.
STORM WARNING UNTIL 6 PM EST THURSDAY FOR ANZ330-340-350-353-
355.
&&
$$
SYNOPSIS...JC
NEAR TERM...MALOIT/JC
SHORT TERM...JC
LONG TERM...PW
AVIATION...MPS
MARINE...MALOIT/NV/PW
HYDROLOGY...JC/PW
TIDES/COASTAL FLOODING...NV
AREA FORECAST DISCUSSION
NWS NEW YORK NY
906 PM EST WED MAR 6 2013
.SYNOPSIS...
A NOR-EASTER WILL AFFECT THE REGION THROUGH FRIDAY. HIGH
PRESSURE THEN BUILDS FROM THE WEST THIS WEEKEND. ANOTHER STORM
SYSTEM APPROACHES THE REGION EARLY NEXT WEEK AND IMPACTS THE AREA
BY MID WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EXPECT 994 HPA LOW OFF THE DELMARVA PENINSULA TO SLOWLY MOVE ENE
TONIGHT...AND STRENGTHEN SLIGHTLY...AS IT MOVES WITH CUTOFF LOW
ABOVE IT. OPERATIONAL SYNOPTIC SCALE MODELS SEEM TO BE UNDER
ESTIMATING STRENGTH OF RIDGING TO THE N/NE OF THE LOW AND HENCE
ARE TOO FAST IN MOVING PRECIPITATION INTO THE TRI-STATE.
ONLY MODELS WHICH SEEM TO HAVE ANY GRASP ON CURRENT SITUATION ARE
THE HRRR AND RUC - AND THIS UPDATE REFLECTS THIS. BASICALLY HAVE
SCALED BACK POPS - ESPECIALLY OVER NW ZONES THIS EVENING AND
REDUCED QPF AND SNOW AMOUNTS. THE LATTER WEER ONLY A FEW TENTHS OF
AN INCH SO SHOULD NOT AMOUNT TO ANY SIGNIFICANT CHANGE IN
ACCUMULATIONS. BASICALLY EXPECT BULK OF PRECIPITATION SHIELD TO
REMAIN OFFSHORE UNTIL AROUND MIDNIGHT - EXCEPT FOR POSSIBLY ALONG
THE SOUTH SHORE OF LONG ISLAND.
LAV GUIDANCE SEEMS TO HAVE GOOD HANDLE ON TEMPERATURES AND
DEWPOINTS - SO UPDATED REFLECTS LATEST THERE THIS EVENING.
SO THROUGH TONIGHT...EXPECTING ONLY AN INCH OR TWO OF SNOWFALL. WILL
LEAVE THE INHERITED WINTER WEATHER ADVISORY AS IS FOR TONIGHT AND
STRETCH IT OUT IN TIME...BUT WILL STRESS THAT MORE OF THE
ACCUMULATION WILL OCCUR AFTER TONIGHT. FOR NEW LONDON COUNTY AND
EASTERN LONG ISLAND...WILL GO WITH A START TIME LATE TONIGHT. THE
WINTER STORM WATCH FOR THESE AREAS WILL BE CANCELLED AS IT APPEARS
THAT WARNING CRITERIA WILL NOT BE MET. FOR THE NW ZONES...WILL
START THE WINTER WEATHER ADVISORY LATER IN TIME. MORE ON THIS IN
THE SHORT TERM SECTION BELOW.
THE WIND ADVISORY WILL REMAIN AS POSTED...WITH THE ADDITION OF ALL
OF NEW LONDON COUNTY. EXPECTING GUSTS UP TO AROUND 50 MPH TONIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE STORM BEGINS TO TURN NE...BUT STILL WELL OUT TO SEA. NAM IS
ALONE IN BRINGING A WARM NOSE ALOFT DURING THE AFTERNOON/NIGHTTIME
HOURS. PREFER THE COLDER THERMAL PROFILES ALOFT OF GFS AND ECMWF.
FOR SURFACE TEMPS...PREFERRED SOMETHING CLOSER TO THE COLDER NAM MOS
GUIDANCE. DAYTIME TEMPS THEREFORE MAINLY IN THE MID TO UPPER 30S.
THERE COULD BE SOME RAIN MIXED IN AT TIMES...BUT THINKING IS THAT
THE ENTIRE AREA SEES A WET SNOW THROUGH THE DAY. GUSTS UP TO 50 MPH
ARE STILL EXPECTED THROUGH THE AFTERNOON ACROSS THE COASTAL
ZONES...SO THE WIND ADVISORY WILL BE MAINTAINED THROUGH THIS TIME.
A STRONG SHORTWAVE THEN ARRIVES FROM THE NW DURING THURSDAY NIGHT
AND INTERACTS WITH AN INVERTED SURFACE TROUGH. THIS WILL KEEP A
LIKELIHOOD OF SNOWFALL ACROSS THE AREA THROUGH THE NIGHT. PRECIP
TYPE THROUGH THE NIGHT IS EXPECTED TO BE ALL SNOW. BY FRIDAY
MORNING...SNOWFALL AMOUNTS OF MOSTLY 3 TO 6 INCHES EXPECTED...WITH
THE HIGHER AMOUNTS GENERALLY OVER CT. HAVE DECIDED TO GO WITH A
WINTER WEATHER ADVISORY FOR THE NW ZONES STARTING THURSDAY NIGHT AND
GOING THROUGH FRIDAY MORNING AS THIS WILL BE THE PERIOD OF MOST OF
THE SNOWFALL FOR THIS EVENT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
INITIALLY...EXPECT A STACKED LOW WELL SOUTH AND EAST OF THE
BENCHMARK EARLY FRIDAY...WITH SHORTWAVE TROUGH TO OUR SOUTH
EVENTUALLY PIVOTING AROUND THE BASE OF THE AFOREMENTIONED LOW LATER
FRIDAY. MODELS IN AGREEMENT WITH REGARD TO LARGE RIDGE BUILDING IN
THIS WEEKEND. DIFFERENCES ARISE WITH NORTHERN STREAM SHORTWAVE
DIGGING ACROSS CANADA...FLATTENING THE RIDGE LATE THIS WEEKEND INTO
EARLY NEXT WEEK. THEN UPSTREAM MID WEST TROUGH APPROACHES EARLY NEXT
WEEK...MONDAY AND TUESDAY. AGAIN...MODELS ARE SLIGHTLY DIFFERENT ON
SUBTLE DETAILS...BUT ALL DO INDICATE THAT THIS TROUGH WILL IMPACT
THE AREA IN SOME FORM LATER MONDAY INTO TUESDAY. LINGERING TROUGH
SLOWLY EXITS WEDNESDAY.
AT THE SURFACE...TIGHT NORTHERLY PRESSURE GRADIENT PERSISTS ON
FRIDAY AS AREA REMAINS BETWEEN DEEP LOW TO THE EAST AND BUILDING
HIGH PRESSURE TO THE WEST. THE HIGH LOOKS TO BUILD IN LATER SATURDAY
THROUGH SUNDAY MORNING...THEN PASSES EAST. A WEAK FRONTAL BOUNDARY
APPROACHES FROM THE NORTH...ASSOCIATED WITH NORTHERN STREAM
MID/UPPER TROUGH...BUT MAIN FRONT AHEAD OF MIDWEST TROUGH DOES NOT
MOVE THROUGH UNTIL SOME TIME LATE MONDAY NIGHT OR TUESDAY. A GENERAL
NW FLOW PREVAILS BEHIND THIS FRONT TUESDAY NIGHT INTO
WEDNESDAY...WITH PERHAPS A WEAK SFC TROUGH IN THE VICINITY WHICH IS
ASSOCIATED WITH LINGERING UPPER TROUGH WEDNESDAY.
AS FOR SENSIBLE WEATHER...WILL DISCARD NAM SOLUTION FOR WARM NOSE
ALOFT (H9-H7 HPA) PER FCST SOUNDINGS AND MAPS...WITH GFS AND ECMWF
MUCH COLDER EARLY FRIDAY. WILL MAINTAIN SNOW AS WEATHER TYPE INTO
FRIDAY...THEN PRECIP TAPERS OFF LATER FRIDAY THROUGH MUCH OF THE
WEEKEND...MAYBE AS A RAIN/SNOW MIX. SOME LIGHT PRECIP POSSIBLE SUNDAY
NIGHT...WITH THE BULK OF THE PRECIP EXPECTED LATE MONDAY INTO
TUESDAY WITH THE FRONT. P-TYPE WILL BE MAINLY RAIN IN WAA PATTERN.
COLDER AIR MOVES IN BEHIND THE FRONT...WITH SNOW SHOWERS POSSIBLE
TUE NIGHT AND WED.
TEMPS WILL REMAIN BELOW NORMAL FRIDAY...THEN WILL WARM TO ABOVE
NORMAL READINGS THIS WEEKEND...THANKS TO RIDGE.
WARMER THEN NORMAL TEMPS CONTINUE MONDAY AND TUESDAY...WITH A RETURN
TO BELOW NORMAL BEHIND THE FRONT TUE NIGHT AND WED. HPC/MEX/ECMWF
BLEND USED.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
SIGNIFICANT AVIATION WEATHER IMPACTS CONTINUE THROUGH FRIDAY WITH
PROLONGED STRONG WINDS...LIGHT RAIN AND SNOW WITH PERIODS OF IFR AS
A NOR-EASTER JUST OFF THE DELMARVA PENINSULA SLOWLY TRACKS EAST OVER
THE ATLANTIC.
TOTAL SNOW FORECAST THROUGH FRIDAY RANGES FROM 3 TO 6 INCHES WITH
MOST ACCUMULATIONS OCCURRING AT NIGHT WITH 1 TO 3 INCHES POSSIBLE
TONIGHT AND THEN ANOTHER 2 TO 4 INCHES POSSIBLE THURSDAY NIGHT. THIS
FORECAST COULD BE A BIT ON THE HIGH SIDE AS TEMPERATURES STAY AT OR
JUST ABOVE FREEZING. RUNWAY ACCUMULATIONS TONIGHT WILL LIKELY
AVERAGE A SLUSHY 1 OR 2 INCHES. NOTE THAT LITTLE OR NO RUNWAY SNOW
ACCUMULATION IS EXPECTED DURING THE DAY ON THURSDAY.
TONIGHT...LIGHT RAIN NEAR THE COAST WILL MIX WITH AND CHANGE TO
SNOW. ACROSS THE INTERIOR...LIGHT SNOW WILL DEVELOP DURING THE
EVENING HOURS AND CONTINUE THROUGH THURSDAY MORNING. GENERALLY MVFR
CONDITIONS UNTIL SNOW DEVELOPS...THEN CONDITIONS DROP TO IFR.
LOW CONFIDENCE FORECAST ON THURSDAY. PERIODS OF SNOW...MIXING WITH
RAIN IN THE AFTERNOON...WILL KEEP CIGS/VSBYS AT IFR FROM TIME TO
TIME...BUT TIMING IS UNCERTAIN. THERE MAY BE A PROLONGED PERIOD OF
VFR CONDITIONS DURING THE MIDDLE OF THE DAY IN BETWEEN BOUTS OF PRECIP.
NORTHEAST WINDS 20-25 KT WITH 35-40 KT GUSTS TONIGHT...BACKING TO
THE NORTH BY THURSDAY MORNING AND DIMINISHING TO 15-20 KT WITH 20-30
KT GUSTS.
STRONG LLWS CONCERNS THROUGH THURSDAY MORNING WITH 50-55 KT WINDS AT
2000 FT AND BELOW.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KLGA FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KEWR FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KTEB FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND REDUCED
VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH CONFIDENCE.
NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KHPN FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KISP FCSTER COMMENTS: TIMING OF SNOW...ONSET OF IFR AND REDUCED VSBY
FOR 9 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH CONFIDENCE. NO
RUNWAY ACCUMULATIONS EXPECTED BEFORE MIDNIGHT.
OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.THU NGT-FRI...N G35KT. IFR WITH LIGHT SNOW ENDING FRI MORNING.
LIGHT OVERNIGHT SNOW ACCUMULATIONS LIKELY...HIGHEST EAST.
.FRI NGT...BECOMING VFR.
.SAT-SUN...VFR.
.MON...VFR...INCREASING S WND LATE DAY.
&&
.MARINE...
MINOR CHANGES TO WIND/WAVE GRIDS TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK - THOUGH WILL
HAVE TO MONITOR WINDS AROUND THE S SHORE BAYS AS ARE SOME
INDICATIONS THAT AN UPGRADE TO A STORM WARNING MIGHT BE IN ORDER
THERE.
GALE WARNINGS REMAIN POSTED FOR THE WESTERN SOUND...NY
HARBOR...AND THE SOUTH SHORE BAYS. STORM WARNINGS REMAIN
ELSEWHERE. THESE WARNINGS CONTINUE THROUGH THURSDAY AFTERNOON.
GALES WILL STILL BE LIKELY DURING THURSDAY NIGHT EVEN THOUGH
WINDS WILL SUBSIDE SOMEWHAT THROUGH THE NIGHT.
A TIGHT PRESSURE GRADIENT ON FRIDAY AS THE WATERS REMAIN BETWEEN
DEPARTING DEEP LOW PRESSURE TO THE EAST AND BUILDING HIGH PRESSURE
TO THE WEST. GALE FORCE WINDS...APPROACHING STORM FORCE FRIDAY OVER
THE EASTERN WATERS...WITH GALES ELSEWHERE WILL SLOWLY IMPROVE FRIDAY
NIGHT AND SATURDAY AS THE HIGH BUILDS. IN FACT...MUCH LIGHTER WINDS
CAN BE EXPECTED LATE SATURDAY INTO SUNDAY AS THE HIGH BUILDS OVER
THE WATERS.
A RETURN FLOW IS FORECAST BY LATE SUNDAY NIGHT INTO MONDAY AS THE
HIGH MOVES EAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST.
VERY ROUGH SEAS FRIDAY WILL SLOWLY SUBSIDE FRIDAY NIGHT INTO
SATURDAY. SEAS REMAIN 3 TO 5 FT OVER THE OCEAN WATERS THROUGH MUCH
OF THE WEEKEND AND INTO MONDAY. THE SHELTERED WATERS WILL BE MUCH
MORE TRANQUIL ONCE THE WINDS DIMINISH THIS WEEKEND.
&&
.HYDROLOGY...
TOTAL LIQUID QPF THROUGH FRI IS CURRENTLY EXPECTED TO BE AROUND 2/3
OF AN INCH ACROSS THE LOWER HUDSON VALLEY...RANGING TO AROUND 1 1/2
INCHES ACROSS EASTERN CT/LI. HYDRO RELATED ISSUES ARE NOT
ANTICIPATED AT THIS TIME WITH THE PRECIPITATION OCCURRING OVER A
RELATIVELY LONG PERIOD OF TIME AND MAINLY FROZEN.
ONCE PRECIP TAPERS OFF LATER FRIDAY...THE NEXT CHANCE FOR
PRECIPITATION...GENERALLY UNDER A HALF AN INCH...WILL OCCUR EARLY
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
WITH A TRACK OF LOW PRESSURE WELL SE OF THE REGION...AND EARLY
BACKING OF FLOW TO THE N/NE...WATERS LEVELS ONLY ROSE TO LOW END
OF EXPECTED RANGES THIS AFTERNOON/EVENING.
DESPITE LARGE SWELLS AFFECTING THE COAST OVERNIGHT INTO THURSDAY
MORNING AND HIGHER ASTRONOMICAL TIDES...NORTHERLY FLOW SHOULD
LIMIT SURGE TO 2 TO 3 FT. EXPECTATION CONTINUES FOR WIDESPREAD
MINOR COASTAL FLOODING FOR MOST OF THE TRI-STATE COASTLINE...WITH
MODERATE COASTAL FLOODING ALONG THE SOUTH SHORE BAYS...OCEAN
FACING COASTLINE...AND TWIN FORKS OF LI...WHERE TIDAL DRAINAGE
WILL BE INHIBITED BY LARGE SWELLS.
MODERATE TO MAJOR BEACH EROSION IS EXPECTED FOR OCEAN FACING
BEACHES AND TWIN FORKS OF LI THROUGH THURSDAY...WITH BREAKERS OF
10 TO 15 FT. THESE WAVES WILL ALSO ENHANCE INUNDATION AND CAUSE
LOCALIZED WASHOVERS AND DAMAGE TO COASTAL STRUCTURES.
THEREAFTER...THE RESIDUAL EASTERLY SWELLS WILL POSE A THREAT FOR
WIDESPREAD MINOR COASTAL FLOODING ISSUES DURING THE TIMES OF THE
MORNING HIGH TIDES THROUGH FRI. THE SOUTH SHORE BAYS...OCEAN
FACING COASTLINE...AND TWIN FORKS OF LI...MAY SEE LOCALIZED MINOR
COASTAL FLOODING DURING THE LOWER AFTERNOON/EVENING HIGH TIDES AS
WELL DUE TO RESTRICTED TIDAL DRAINAGE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR CTZ008-012.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR CTZ008>012.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR CTZ005>007-
009>011.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
CTZ009>012.
NY...COASTAL FLOOD WARNING FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ079-081.
WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR NYZ079-081.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NYZ071>075-078>081-
176>179.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NYZ067-068.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NYZ069>075-
078-080-176>179.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NYZ072-074-075-178.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ071-073-078-176-177.
COASTAL FLOOD WARNING FROM 2 AM TO 7 AM EST THURSDAY FOR
NYZ080-179.
NJ...WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NJZ006.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NJZ002-004-103.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NJZ006-
104>108.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NJZ006-106-108.
MARINE...GALE WARNING UNTIL 6 PM EST FRIDAY FOR ANZ335-338-345.
STORM WARNING UNTIL 6 PM EST THURSDAY FOR ANZ330-340-350-353-
355.
&&
$$
SYNOPSIS...JC
NEAR TERM...JC/MALOIT
SHORT TERM...JC
LONG TERM...PW
AVIATION...MPS
MARINE...MALOIT/NV/PW
HYDROLOGY...JC/PW
TIDES/COASTAL FLOODING...NV
AREA FORECAST DISCUSSION
NWS NEW YORK NY
712 PM EST WED MAR 6 2013
.SYNOPSIS...
A NOR-EASTER WILL AFFECT THE REGION THROUGH FRIDAY. HIGH
PRESSURE THEN BUILDS FROM THE WEST THIS WEEKEND. ANOTHER STORM
SYSTEM APPROACHES THE REGION EARLY NEXT WEEK AND IMPACTS THE AREA
BY MID WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EXPECT 994 HPA LOW OFF THE DELMARVA PENINSULA TO SLOWLY MOVE ENE
TONIGHT...AND STRENGTHEN SLIGHTLY...AS IT MOVES WITH CUTOFF LOW
ABOVE IT. OPERATIONAL SYNOPTIC SCALE MODELS SEEM TO BE UNDER
ESTIMATING STRENGTH OF RIDGING TO THE N/NE OF THE LOW AND HENCE
ARE TOO FAST IN MOVING PRECIPITATION INTO THE TRI-STATE.
ONLY MODELS WHICH SEEM TO HAVE ANY GRASP ON CURRENT SITUATION ARE
THE HRRR AND RUC - AND THIS UPDATE REFLECTS THIS. BASICALLY HAVE
SCALED BACK POPS - ESPECIALLY OVER NW ZONES THIS EVENING AND
REDUCED QPF AND SNOW AMOUNTS. THE LATTER WEER ONLY A FEW TENTHS OF
AN INCH SO SHOULD NOT AMOUNT TO ANY SIGNIFICANT CHANGE IN
ACCUMULATIONS. BASICALLY EXPECT BULK OF PRECIPITATION SHIELD TO
REMAIN OFFSHORE UNTIL AROUND MIDNIGHT - EXCEPT FOR POSSIBLY ALONG
THE SOUTH SHORE OF LONG ISLAND.
LAV GUIDANCE SEEMS TO HAVE GOOD HANDLE ON TEMPERATURES AND
DEWPOINTS - SO UPDATED REFLECTS LATEST THERE THIS EVENING.
SO THROUGH TONIGHT...EXPECTING ONLY AN INCH OR TWO OF SNOWFALL. WILL
LEAVE THE INHERITED WINTER WEATHER ADVISORY AS IS FOR TONIGHT AND
STRETCH IT OUT IN TIME...BUT WILL STRESS THAT MORE OF THE
ACCUMULATION WILL OCCUR AFTER TONIGHT. FOR NEW LONDON COUNTY AND
EASTERN LONG ISLAND...WILL GO WITH A START TIME LATE TONIGHT. THE
WINTER STORM WATCH FOR THESE AREAS WILL BE CANCELLED AS IT APPEARS
THAT WARNING CRITERIA WILL NOT BE MET. FOR THE NW ZONES...WILL
START THE WINTER WEATHER ADVISORY LATER IN TIME. MORE ON THIS IN
THE SHORT TERM SECTION BELOW.
THE WIND ADVISORY WILL REMAIN AS POSTED...WITH THE ADDITION OF ALL
OF NEW LONDON COUNTY. EXPECTING GUSTS UP TO AROUND 50 MPH TONIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE STORM BEGINS TO TURN NE...BUT STILL WELL OUT TO SEA. NAM IS
ALONE IN BRINGING A WARM NOSE ALOFT DURING THE AFTERNOON/NIGHTTIME
HOURS. PREFER THE COLDER THERMAL PROFILES ALOFT OF GFS AND ECMWF.
FOR SURFACE TEMPS...PREFERRED SOMETHING CLOSER TO THE COLDER NAM MOS
GUIDANCE. DAYTIME TEMPS THEREFORE MAINLY IN THE MID TO UPPER 30S.
THERE COULD BE SOME RAIN MIXED IN AT TIMES...BUT THINKING IS THAT
THE ENTIRE AREA SEES A WET SNOW THROUGH THE DAY. GUSTS UP TO 50 MPH
ARE STILL EXPECTED THROUGH THE AFTERNOON ACROSS THE COASTAL
ZONES...SO THE WIND ADVISORY WILL BE MAINTAINED THROUGH THIS TIME.
A STRONG SHORTWAVE THEN ARRIVES FROM THE NW DURING THURSDAY NIGHT
AND INTERACTS WITH AN INVERTED SURFACE TROUGH. THIS WILL KEEP A
LIKELIHOOD OF SNOWFALL ACROSS THE AREA THROUGH THE NIGHT. PRECIP
TYPE THROUGH THE NIGHT IS EXPECTED TO BE ALL SNOW. BY FRIDAY
MORNING...SNOWFALL AMOUNTS OF MOSTLY 3 TO 6 INCHES EXPECTED...WITH
THE HIGHER AMOUNTS GENERALLY OVER CT. HAVE DECIDED TO GO WITH A
WINTER WEATHER ADVISORY FOR THE NW ZONES STARTING THURSDAY NIGHT AND
GOING THROUGH FRIDAY MORNING AS THIS WILL BE THE PERIOD OF MOST OF
THE SNOWFALL FOR THIS EVENT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
INITIALLY...EXPECT A STACKED LOW WELL SOUTH AND EAST OF THE
BENCHMARK EARLY FRIDAY...WITH SHORTWAVE TROUGH TO OUR SOUTH
EVENTUALLY PIVOTING AROUND THE BASE OF THE AFOREMENTIONED LOW LATER
FRIDAY. MODELS IN AGREEMENT WITH REGARD TO LARGE RIDGE BUILDING IN
THIS WEEKEND. DIFFERENCES ARISE WITH NORTHERN STREAM SHORTWAVE
DIGGING ACROSS CANADA...FLATTENING THE RIDGE LATE THIS WEEKEND INTO
EARLY NEXT WEEK. THEN UPSTREAM MID WEST TROUGH APPROACHES EARLY NEXT
WEEK...MONDAY AND TUESDAY. AGAIN...MODELS ARE SLIGHTLY DIFFERENT ON
SUBTLE DETAILS...BUT ALL DO INDICATE THAT THIS TROUGH WILL IMPACT
THE AREA IN SOME FORM LATER MONDAY INTO TUESDAY. LINGERING TROUGH
SLOWLY EXITS WEDNESDAY.
AT THE SURFACE...TIGHT NORTHERLY PRESSURE GRADIENT PERSISTS ON
FRIDAY AS AREA REMAINS BETWEEN DEEP LOW TO THE EAST AND BUILDING
HIGH PRESSURE TO THE WEST. THE HIGH LOOKS TO BUILD IN LATER SATURDAY
THROUGH SUNDAY MORNING...THEN PASSES EAST. A WEAK FRONTAL BOUNDARY
APPROACHES FROM THE NORTH...ASSOCIATED WITH NORTHERN STREAM
MID/UPPER TROUGH...BUT MAIN FRONT AHEAD OF MIDWEST TROUGH DOES NOT
MOVE THROUGH UNTIL SOME TIME LATE MONDAY NIGHT OR TUESDAY. A GENERAL
NW FLOW PREVAILS BEHIND THIS FRONT TUESDAY NIGHT INTO
WEDNESDAY...WITH PERHAPS A WEAK SFC TROUGH IN THE VICINITY WHICH IS
ASSOCIATED WITH LINGERING UPPER TROUGH WEDNESDAY.
AS FOR SENSIBLE WEATHER...WILL DISCARD NAM SOLUTION FOR WARM NOSE
ALOFT (H9-H7 HPA) PER FCST SOUNDINGS AND MAPS...WITH GFS AND ECMWF
MUCH COLDER EARLY FRIDAY. WILL MAINTAIN SNOW AS WEATHER TYPE INTO
FRIDAY...THEN PRECIP TAPERS OFF LATER FRIDAY THROUGH MUCH OF THE
WEEKEND...MAYBE AS A RAIN/SNOW MIX. SOME LIGHT PRECIP POSSIBLE SUNDAY
NIGHT...WITH THE BULK OF THE PRECIP EXPECTED LATE MONDAY INTO
TUESDAY WITH THE FRONT. P-TYPE WILL BE MAINLY RAIN IN WAA PATTERN.
COLDER AIR MOVES IN BEHIND THE FRONT...WITH SNOW SHOWERS POSSIBLE
TUE NIGHT AND WED.
TEMPS WILL REMAIN BELOW NORMAL FRIDAY...THEN WILL WARM TO ABOVE
NORMAL READINGS THIS WEEKEND...THANKS TO RIDGE.
WARMER THEN NORMAL TEMPS CONTINUE MONDAY AND TUESDAY...WITH A RETURN
TO BELOW NORMAL BEHIND THE FRONT TUE NIGHT AND WED. HPC/MEX/ECMWF
BLEND USED.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
SIGNIFICANT AVIATION WEATHER IMPACTS CONTINUE THROUGH FRIDAY WITH
PROLONGED STRONG WINDS...LIGHT RAIN AND SNOW WITH PERIODS OF IFR AS
A NOR-EASTER JUST OFF THE DELMARVA PENINSULA SLOWLY TRACKS EAST OVER
THE ATLANTIC.
TOTAL SNOW FORECAST THROUGH FRIDAY RANGES FROM 3 TO 6 INCHES WITH
MOST ACCUMULATIONS OCCURRING AT NIGHT WITH 1 TO 3 INCHES POSSIBLE
TONIGHT AND THEN ANOTHER 2 TO 4 INCHES POSSIBLE THURSDAY NIGHT. THIS
FORECAST COULD BE A BIT ON THE HIGH SIDE AS TEMPERATURES STAY AT OR
JUST ABOVE FREEZING. RUNWAY ACCUMULATIONS TONIGHT WILL LIKELY
AVERAGE A SLUSHY 1 OR 2 INCHES. NOTE THAT LITTLE OR NO RUNWAY SNOW
ACCUMULATION IS EXPECTED DURING THE DAY ON THURSDAY.
TONIGHT...LIGHT RAIN NEAR THE COAST WILL MIX WITH AND CHANGE TO
SNOW. ACROSS THE INTERIOR...LIGHT SNOW WILL DEVELOP DURING THE
EVENING HOURS AND CONTINUE THROUGH THURSDAY MORNING. GENERALLY MVFR
CONDITIONS UNTIL SNOW DEVELOPS...THEN CONDITIONS DROP TO IFR.
LOW CONFIDENCE FORECAST ON THURSDAY. PERIODS OF SNOW...MIXING WITH
RAIN IN THE AFTERNOON...WILL KEEP CIGS/VSBYS AT IFR FROM TIME TO
TIME...BUT TIMING IS UNCERTAIN. THERE MAY BE A PROLONGED PERIOD OF
VFR CONDITIONS DURING THE MIDDLE OF THE DAY IN BETWEEN BOUTS OF PRECIP.
NORTHEAST WINDS 20-25 KT WITH 35-40 KT GUSTS TONIGHT...BACKING TO
THE NORTH BY THURSDAY MORNING AND DIMINISHING TO 15-20 KT WITH 20-30
KT GUSTS.
STRONG LLWS CONCERNS THROUGH THURSDAY MORNING WITH 50-55 KT WINDS AT
2000 FT AND BELOW.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KLGA FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KEWR FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KTEB FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND REDUCED
VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH CONFIDENCE.
NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KHPN FCSTER COMMENTS: TIMING OF LIGHT SNOW...ONSET OF IFR AND
REDUCED VSBY FOR 8 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH
CONFIDENCE. NO RUNWAY ACCUMULATIONS EXPECTED UNTIL WELL AFTER DARK.
KISP FCSTER COMMENTS: TIMING OF SNOW...ONSET OF IFR AND REDUCED VSBY
FOR 9 PM LOCAL AT THE EARLIEST. WIND FCST IS HIGH CONFIDENCE. NO
RUNWAY ACCUMULATIONS EXPECTED BEFORE MIDNIGHT.
OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.THU NGT-FRI...N G35KT. IFR WITH LIGHT SNOW ENDING FRI MORNING.
LIGHT OVERNIGHT SNOW ACCUMULATIONS LIKELY...HIGHEST EAST.
.FRI NGT...BECOMING VFR.
.SAT-SUN...VFR.
.MON...VFR...INCREASING S WND LATE DAY.
&&
.MARINE...
MINOR CHANGES TO WIND/WAVE GRIDS TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK - THOUGH WILL
HAVE TO MONITOR WINDS AROUND THE S SHORE BAYS AS ARE SOME
INDICATIONS THAT AN UPGRADE TO A STORM WARNING MIGHT BE IN ORDER
THERE.
GALE WARNINGS REMAIN POSTED FOR THE WESTERN SOUND...NY
HARBOR...AND THE SOUTH SHORE BAYS. STORM WARNINGS REMAIN
ELSEWHERE. THESE WARNINGS CONTINUE THROUGH THURSDAY AFTERNOON.
GALES WILL STILL BE LIKELY DURING THURSDAY NIGHT EVEN THOUGH
WINDS WILL SUBSIDE SOMEWHAT THROUGH THE NIGHT.
A TIGHT PRESSURE GRADIENT ON FRIDAY AS THE WATERS REMAIN BETWEEN
DEPARTING DEEP LOW PRESSURE TO THE EAST AND BUILDING HIGH PRESSURE
TO THE WEST. GALE FORCE WINDS...APPROACHING STORM FORCE FRIDAY OVER
THE EASTERN WATERS...WITH GALES ELSEWHERE WILL SLOWLY IMPROVE FRIDAY
NIGHT AND SATURDAY AS THE HIGH BUILDS. IN FACT...MUCH LIGHTER WINDS
CAN BE EXPECTED LATE SATURDAY INTO SUNDAY AS THE HIGH BUILDS OVER
THE WATERS.
A RETURN FLOW IS FORECAST BY LATE SUNDAY NIGHT INTO MONDAY AS THE
HIGH MOVES EAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST.
VERY ROUGH SEAS FRIDAY WILL SLOWLY SUBSIDE FRIDAY NIGHT INTO
SATURDAY. SEAS REMAIN 3 TO 5 FT OVER THE OCEAN WATERS THROUGH MUCH
OF THE WEEKEND AND INTO MONDAY. THE SHELTERED WATERS WILL BE MUCH
MORE TRANQUIL ONCE THE WINDS DIMINISH THIS WEEKEND.
&&
.HYDROLOGY...
TOTAL LIQUID QPF THROUGH FRI IS CURRENTLY EXPECTED TO BE AROUND 2/3
OF AN INCH ACROSS THE LOWER HUDSON VALLEY...RANGING TO AROUND 1 1/2
INCHES ACROSS EASTERN CT/LI. HYDRO RELATED ISSUES ARE NOT
ANTICIPATED AT THIS TIME WITH THE PRECIPITATION OCCURRING OVER A
RELATIVELY LONG PERIOD OF TIME AND MAINLY FROZEN.
ONCE PRECIP TAPERS OFF LATER FRIDAY...THE NEXT CHANCE FOR
PRECIPITATION...GENERALLY UNDER A HALF AN INCH...WILL OCCUR EARLY
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
WITH A TRACK OF LOW PRESSURE WELL SE OF THE REGION...WINDS HAVE
ALREADY TURNED NNE...RESULTING IN WATERS LEVELS ONLY RISING TO LOW
END OF EXPECTED RANGES. LOCALIZED MINOR COASTAL FLOODING OCCURRED
IN THE SOUTH SHORE BAYS AND NEW YORK HARBOR. EXPECTATION IS THAT
WIDESPREAD MINOR COASTAL FLOOD THRESHOLDS WILL BE REACHED ACROSS
WESTERN LONG ISLAND SOUND SHORTLY...EXCEPT LOCALLY MODERATE ALONG THE
FAR WESTERN TIP OF LI SOUND WHERE 3 TO 5 FT OF WAVE ACTION SHOULD
ENHANCE INUNDATION. LARGE EASTERLY SWELLS AND NE FLOW HAVE THE
TWIN FORKS ON TRACK FOR MINOR TO LOCALLY MODERATE COASTAL FLOODING
AS WELL EARLY THIS EVENING.
DESPITE BUILDING SWELLS AFFECTING THE COAST OVERNIGHT INTO
THURSDAY MORNING AND HIGHER ASTRONOMICAL TIDES...NORTHERLY FLOW
SHOULD LIMIT SURGE TO 2 TO 3 FT. EXPECTATION CONTINUES FOR
WIDESPREAD MINOR COASTAL FLOODING FOR MOST OF THE TRI-STATE
COASTLINE...WITH MODERATE COASTAL FLOODING ALONG THE SOUTH SHORE
BAYS...OCEAN FACING COASTLINE...AND TWIN FORKS OF LI...WHERE
DRAINAGE WILL BE RESTRICTED BY THE SWELLS.
MODERATE TO MAJOR BEACH EROSION ARE EXPECTED FOR OCEAN FACING
BEACHES AND TWIN FORKS OF LI THROUGH THURSDAY...WITH BREAKERS OF
10 TO 15 FT. THESE WAVES WILL ALSO ENHANCE INUNDATION AND CAUSE
LOCALIZED WASHOVERS AND DAMAGE TO COASTAL STRUCTURES.
THEREAFTER...THE RESIDUAL EASTERLY SWELLS WILL LIKELY CAUSE MINOR
COASTAL FLOODING ISSUES DURING THE TIMES OF THE MORNING HIGH
TIDES THROUGH FRI. THE SOUTH SHORE BAYS...OCEAN FACING
COASTLINE...AND TWIN FORKS OF LI...MAY SEE LOCALIZED MINOR
COASTAL FLOODING DURING THE LOWER AFTERNOON/EVENING HIGH TIDES AS
WELL DUE TO RESTRICTED TIDAL DRAINAGE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR CTZ008-012.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR CTZ008>012.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR CTZ005>007-
009>011.
COASTAL FLOOD ADVISORY UNTIL 8 PM EST THIS EVENING FOR CTZ009-
010.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
CTZ009>012.
NY...COASTAL FLOOD WARNING UNTIL 8 PM EST THIS EVENING FOR NYZ071-
073-079-081-176-177.
COASTAL FLOOD WARNING FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ079-081.
WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO NOON EST FRIDAY
FOR NYZ079-081.
WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NYZ071>075-078>081-
176>179.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NYZ067-068.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NYZ069>075-
078-080-176>179.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NYZ072-074-075-178.
COASTAL FLOOD ADVISORY UNTIL 8 PM EST THIS EVENING FOR NYZ078.
COASTAL FLOOD ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
NYZ071-073-078-176-177.
COASTAL FLOOD WARNING FROM 2 AM TO 7 AM EST THURSDAY FOR
NYZ080-179.
NJ...WIND ADVISORY UNTIL 6 PM EST THURSDAY FOR NJZ006.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON EST FRIDAY
FOR NJZ002-004-103.
WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NJZ006-
104>108.
COASTAL FLOOD ADVISORY FROM 2 AM TO 5 AM EST THURSDAY FOR
NJZ006-106-108.
MARINE...GALE WARNING UNTIL 6 PM EST FRIDAY FOR ANZ335-338-345.
STORM WARNING UNTIL 6 PM EST THURSDAY FOR ANZ330-340-350-353-
355.
&&
$$
SYNOPSIS...JC
NEAR TERM...MALOIT/JC
SHORT TERM...JC
LONG TERM...PW
AVIATION...MPS
MARINE...MALOIT/NV/PW
HYDROLOGY...JC/PW
TIDES/COASTAL FLOODING...NV
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
623 PM EST WED MAR 6 2013
.SYNOPSIS...
A STRONG COASTAL LOW LOCATED OFFSHORE OF VIRGINIA WILL SLOWLY
MOVE EASTWARD THROUGH FRIDAY. HIGH PRESSURE WILL BUILD ACROSS THE
AREA FOR SATURDAY INTO SUNDAY. AN AREA OF LOW PRESSURE WILL MOVE
THROUGH THE OHIO RIVER VALLEY ON MONDAY INTO MONDAY NIGHT AND PASS
TO OUR NORTH ON TUESDAY. THIS LOW WILL BRING A COLD FRONT THROUGH
OUR AREA MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
BASED ON THE LATEST RAP AND HRRR AND THE HI-RES ARW. WE ARE GOING
TO CANCEL THE WINTER RELATED ADVISORIES OUTSIDE OF NJ. SOME
WRAPAROUND IS FORECAST TO CONTINUE INTO NJ AND WE ARE SLOWLY
COOLING (MORE FROM THE PCPN THAN ADVECTION). SO WANT TO SEE WHAT
DOES OR DOES NOT OCCUR OVER THE NEXT COUPLE OF HOURS BEFORE MAKING
A DECISION ABOUT THE REST OF THE ADVISORY. TEMPS IF ANYTHING ARE
SLIGHTLY WARMER THAN OUR EXPECTATIONS. FCST AND ACAR SOUNDINGS
ARE SHOWING WINDS BELOW 850MB DIMINISHING AND IF THE TREND
CONTINUES, WE MAY BE ABLE TO CANCEL SOME OF THE WIND RELATED
PRODUCTS WEST WITH THE NEXT UPDATE.
ALTHOUGH THE MID LEVEL LOW WAS JUST MOVING OFF THE COAST, AND WE
ARGUABLY WOULD BE GETTING INTO A DEFORMATION ZONE FOR A WHILE IN
THE NEAR TERM, THE Q-VECTOR CONVERGENCE AND FRONTOGENESIS ARE
MODELLED TO ALREADY BE EXITING TO THE EAST. MOREOVER, THE MODEL
THAT WOULD GIVE US SIGNIFICANT PRECIPITATION EARLY IN THE PERIOD
(THE NAM) HAS BEEN WOEFULLY OVERDONE THUS FAR WITH THIS SYSTEM.
FINALLY, WE SIMPLY HAVEN`T SEEN ANY SIGNIFICANT COLUMN COOLING
THUS FAR WITH THIS SYSTEM. WE HAVE OPTED TO GO WITH THE LOWER QPF
AND THE MILDER GUIDANCE WITH THE NEAR TERM (HENCE THE MIN
TEMPERATURES), AND THAT KNOCKS THE SNOWFALL AMOUNTS DOWN RATHER A
BIT. WE HAVE KEPT AN ADVISORY GOING ALONG THE INTERSTATE 95
CORRIDOR WITH LOW-END AMOUNTS, BUT THIS MAY JUST BE A STEP IN THE
DIRECTION OF CANCELLING THE SNOW HEADLINES COMPLETELY.
WINDS ARE EXPECTED TO ONLY SLOWLY DIMINISH OVERNIGHT AS THEY BACK
FROM NORTHEAST TO NORTH. THE HIGH WIND WARNING AND WIND ADVISORY
REMAIN IN EFFECT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
WE AGAIN SIDE WITH THE ECMWF AND GFS AS OPPOSED TO THE NAM ON
THURSDAY. THIS MAKES TOMORROW A CLOUDY AND BRISK BUT NOT ADVISORY
DAY ON LAND FOR EARLY MARCH WITH MAINLY CHANCE POPS THAT LOWER
DURING THE COURSE OF THE DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AT THE BEGINNING OF THE EXTENDED, WE WILL CONTINUE TO BE UNDER THE
INFLUENCE OF SLOW MOVING LOW PRESSURE SYSTEM TO OUR EAST. EVEN
THOUGH THE LOW IS FORECAST TO BE WELL TO OUR EAST THURSDAY NIGHT
INTO FRIDAY, MODELS CONTINUE TO INDICATE AN AREA OF MOISTURE
SWINGING BACK TO THE WEST OF THE SYSTEM AND ACROSS OUR AREA. AT THE
SAME TIME, A SHORT WAVE ALOFT WILL BE DIVING OUT OF THE GREAT LAKES
REGION WHICH MAY HELP PULL SOME ADDITIONAL MOISTURE DOWN AND ALSO
ENHANCE LIFT ACROSS THE AREA. THERE IS SOME DISAGREEMENT WITH THE
AMOUNTS OF QPF THAT IS FORECAST WITH VARIOUS MODELS. FOR INSTANCE,
THE NAM CONTINUES TO BE THE HIGHEST WITH AMOUNTS, BRINGING NEAR AN
INCH OF LIQUID-EQUIVALENT, WHILE THE GFS IS LOWEST WITH GENERALLY
AROUND ONE-THIRD MAX. THE OTHER MODELS ARE ALL SOMEWHERE IN BETWEEN,
SO HAVE DECIDED TO FOLLOW ALONG WITH HPC/WPC AND USED A BLEND OF THE
GUIDANCE, NOT COUNTING THE NAM SINCE IT IS THE EXTREME. MOST OF THE
PRECIPITATION WILL FALL OVERNIGHT THURSDAY INTO FRIDAY MORNING, AND
THERMAL PROFILES INDICATE THAT SNOW WILL FALL OVERNIGHT INTO FRIDAY
MORNING FOR MOST AREAS. USING THE FORECAST QPF AMOUNTS, WE COME UP
WITH 1-3 INCHES ACROSS OUR NORTHEASTERN HALF OF THE CWA, WITH AN
INCH OR LESS ACROSS THE SOUTHWESTERN HALF. WE HAVE DECIDED TO HOLD
OFF ON ANY KIND OF ADVISORY FOR THE NORTHERN COUNTIES SINCE THERE
REMAINS SOME DIFFERENCES IN THE QPF AMOUNTS, WHICH WOULD ALTER THE
SNOW AMOUNTS.
THE PRECIPITATION SHOULD BEGIN TO TAPER OFF THROUGH THE DAY FRIDAY,
AND BE DONE WITH BY FRIDAY NIGHT AS THE SHORT WAVE COMPLETELY PUSHES
THROUGH AND THE LOW PRESSURE TO OUR EAST MOVES FURTHER OUT TO SEA.
HIGH PRESSURE IS THEN FORECAST TO BUILD OVER THE AREA SATURDAY INTO
SUNDAY. WITH RIDGING ALOFT BUILDING ACROSS THE AREA, THICKNESSES
WILL INCREASE, AND TEMPERATURES WILL RISE OVER THE WEEKEND.
TEMPERATURES ARE EXPECTED TO RISE INTO THE 50S FOR MANY AREAS. WITH
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT, DRY WEATHER IS EXPECTED
SATURDAY INTO SUNDAY.
A WEAK FRONTAL BOUNDARY IS FORECAST TO APPROACH THE AREA FROM THE
NORTH SUNDAY NIGHT INTO MONDAY, BUT WILL LIKELY STALL TO OUR NORTH,
WHILE SEVERAL SHORT WAVE DISTURBANCES SLIDE ACROSS THE AREA IN THE
SOUTHWEST FLOW ALOFT. WE WILL KEEP A SLIGHT CHANCE/CHANCE OF
PRECIPITATION IN THE FORECAST DUE TO THE PROXIMITY OF THESE FEATURES.
THE NEXT BEST CHANCE OF PRECIPITATION IS EXPECTED TO BE MONDAY NIGHT
INTO TUESDAY. THIS IS IN ASSOCIATION WITH A FRONTAL BOUNDARY THAT IS
FORECAST TO MOVE THROUGH THE AREA AS AN AREA OF LOW PRESSURE MOVES
TO OUR NORTH. THERE IS SOME SLIGHT TIMING DIFFERENCES WITH THE GFS
AND ECMWF, BUT BOTH DO INDICATE MONDAY NIGHT INTO TUESDAY AS BEING
THE BEST TIME PERIOD. TEMPERATURES ARE EXPECTED TO BE WARM ENOUGH TO
KEEP MOST AREAS RAIN, ALTHOUGH THERE COULD BE SOME MIXTURE OF
RAIN/SNOW IF THE PRECIPITATION DOES BEGIN MONDAY NIGHT.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MVFR TO IFR CONDITIONS IN RAIN MIXING WITH AND/OR CHANGING TO SNOW
ARE FORECAST THROUGH THE EVENING, THEN IMPROVING CONDITIONS ARE
FORECAST. WINDS GUSTING TO AROUND 40 KT WILL BACK FROM NORTHEAST TO
EAST AND THEN DIMINISH GRADUALLY OVERNIGHT. THURSDAY WILL FEATURE
SOME MVFR CLOUDINESS EARLIER AND THEN SOME VFR CLOUDINESS WITH NORTH
WINDS GUSTING TO AROUND 30 KT.
OUTLOOK...
THURSDAY NIGHT-FRIDAY...PERIODS OF MVFR, POSSIBLE IFR, WITH A CHANCE
OF SNOW OR RAIN. IMPROVING CONDITIONS BY LATE FRIDAY AFTERNOON. WIND
GUSTS AROUND 20-25 KNOTS.
FRIDAY NIGHT-SUNDAY NIGHT...MOSTLY VFR EXPECTED.
&&
.MARINE...
THE DEEPENING LOW PUSHING AGAINST HIGH PRESSURE TO THE NORTH AND
WEST WILL KEEP STORM FORCE WINDS GOING ON THE ATLANTIC WATERS
THROUGH TONIGHT. WE EXPECT STORM FORCE WINDS TO LESSEN TO GALES ON
THE ATLANTIC ON THURSDAY. WE EXPECT THAT TO HAPPEN OVER THE LOWER
BAY THIS EVENING. GALES WILL CONTINUE EVERYWHERE THROUGH TOMORROW.
OUTLOOK...
GALE FORCE, OR NEAR GALE FORCE WINDS WILL LIKELY CONTINUE ACROSS THE
ATLANTIC COASTAL WATERS FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT AS
THE PRESSURE GRADIENT REMAINS TIGHT WITH THE LOW PRESSURE TO OUR
EAST SLOWLY MOVING OUT. BY FRIDAY NIGHT AND SATURDAY, HIGH PRESSURE
PUSHES INTO THE AREA, AND WINDS SHOULD DIMINISH TO SMALL CRAFT
LEVELS, AND FINALLY BELOW SMALL CRAFT LEVELS SATURDAY INTO SUNDAY AS
HIGH PRESSURE BUILDS ACROSS THE AREA. EVEN THOUGH WINDS ARE
DIMINISHING OVER THE WEEKEND, SEAS ARE FORECAST TO REMAIN ELEVATED
THROUGH SUNDAY.
&&
.TIDES/COASTAL FLOODING...
UPDATE PRODUCT TO MOVE PAST THE CURRENT HIGH TIDE CYCLE ONM THE
OCEAN FRONT AND DELAWARE BAY.
COASTAL FLOOD WARNING HAS BEEN EXTENDED INTO FRIDAY MORNING HIGH
TIDE IN DELAWARE BAY, ALONG OUR PART OF RARITAN BAY AND ALONG THE
ATLANTIC COAST. THE COASTAL FLOOD ADVISORY FOR TIDAL SECTIONS OF
THE DELAWARE RIVER WAS EXTENDED THROUGH THE THURSDAY MORNING HIGH
TIDE CYCLE. NO HEADLINES FOR CHESAPEAKE BAY YET.
TIDAL DEPARTURES ON THE OCEANSIDE ARE CURRENTLY 2.5 TO 4.0 FEET
ABOVE NORMAL AND IN THE TIDAL DELAWARE RIVER AROUND 2.0 FEET ABOVE
NORMAL. TIDAL DEPARTURES FROM NORMAL IN CHESAPEAKE BAY ARE 1.5 FEET
OR LESS.
THE MDL ESTOFS GUIDANCE WHICH HAS BEEN HIGHER HAS BEEN VERIFYING THE
BEST. OUR IN HOUSE PROCEDURES ARE PRODUCING SIMILAR DEPARTURES AND
WE ARE ANTICIPATING AROUND 3.5 FEET TIDAL DEPARTURES WITH THE
OVERNIGHT EARLY THURSDAY MORNING HIGH TIDE CYCLE. PART OF THIS
STABILIZATION IS DUE TO THE BACKING OF THE WINDS MORE TO THE NORTH.
THIS STILL GETS ALL OF OUR LOWER DELAWARE BAY AS WELL AS OCEAN AND
RARITAN BAY TIDE SITES WELL INTO MODERATE TIDAL FLOODING LEVELS.
LOCAL PROCEDURES AND DBOFS THEN GETS THE TIDAL DELAWARE INTO MINOR
TIDAL FLOODING LEVELS FOR THE NEXT TWO HIGH TIDE CYCLES. THE
COMBINATION OF WIND AND WAVE ACTION WILL MAKE THE EARLY THURSDAY
MORNING HIGH TIDE THE GREATEST IMPACTING HIGH TIDE FOR THIS EVENT.
UNFORTUNATELY WITH THE LOW PRESSURE SYSTEM MEANDERING OFFSHORE AND
THE PREVAILING WIND DIRECTION REMAINING NORTH (WHICH KEEPS SOME
ONSHORE FLOW WITH THE EKMAN SPIRAL), THE IMPROVEMENT IN
TIDAL DEPARTURES WILL BE SLOW. WHILE THE THURSDAY LATE AFTERNOON AND
EARLY EVENING HIGH TIDE CYCLE APPEARS TO BE MINOR, THE HIGHER
ASTRONOMICAL TIDE FOR FRIDAY MORNING IS LIKELY TO REACH MODERATE
LEVELS AGAIN. WE ARE GETTING A ZERO SUM GAIN AS A PREDICTED DROP IN
TIDAL DEPARTURES IS OFFSET BY HIGHER ASTRONOMICAL TIDES AS WE GET
CLOSER TO THE NEW MOON. SO WHILE LEVELS ARE NOT EXPECTED TO RIVAL
EARLY THURSDAY`S HIGH TIDES, MODERATE TIDAL FLOODING COULD STILL BE
REACHED. WITH THE SHORE IN A WEAKENED CONDITION, WE DECIDED TO
EXTEND THE WARNING. THE ESTOFS GUIDANCE ONLY SLOWLY IMPROVES FOR
FRIDAY NIGHT AND SATURDAY. SO AT THE LEAST ADDITIONAL MINOR TIDAL
FLOODING IS POSSIBLE, ESPECIALLY WITH THE SATURDAY MORNING HIGH TIDE
CYCLE.
GUIDANCE IS MORE OPTIMISTIC WITH THE TIDAL DELAWARE BEYOND THE
THURSDAY MORNING HIGH TIDE. RIGHT NOW CBOFS GUIDANCE IS KEEPING OUR
SIDE OF CHESAPEAKE BAY BELOW COASTAL FLOOD ADVISORY CRITERIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ070-071-102-
104-106.
COASTAL FLOOD ADVISORY UNTIL NOON EST THURSDAY FOR PAZ070-071.
NJ...COASTAL FLOOD WARNING UNTIL 9 AM EST FRIDAY FOR NJZ012>014-
020>027.
HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR NJZ013-014-020-
022>027.
WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR NJZ012>015-
017>020-026-027.
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ012-015>019-
021.
COASTAL FLOOD ADVISORY UNTIL NOON EST THURSDAY FOR NJZ016>019.
DE...COASTAL FLOOD WARNING UNTIL 9 AM EST FRIDAY FOR DEZ002>004.
HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR DEZ003-004.
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR DEZ001-002.
COASTAL FLOOD ADVISORY UNTIL NOON EST THURSDAY FOR DEZ001.
MD...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MDZ008-012-015-
019-020.
MARINE...STORM WARNING UNTIL 6 AM EST THURSDAY FOR ANZ450>455.
GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ430.
STORM WARNING UNTIL 8 PM EST THIS EVENING FOR ANZ431.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DELISI/GIGI/HEAVENER
SHORT TERM...DELISI/HEAVENER
LONG TERM...ROBERTSON
AVIATION...DELISI/HEAVENER/ROBERTSON
MARINE...DELISI/HEAVENER/ROBERTSON
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
900 PM CST WED MAR 6 2013
.DISCUSSION...
ISSUED 900 PM CST WED MAR 6 2013
UPDATED THE FORECAST TO KEEP LOW CLOUDS IN THE FORECAST LONGER
TONIGHT AND ALSO NUDGE LOW TEMPERATURES UP A BIT DUE TO LINGERING
LOW CLOUDS. MOSTLY CLOUDY TO OVERCAST SKIES TONIGHT EXCEPT LESS
CLOUD COVER OVER 4 SW COUNTIES OF SCHUYLER...SCOTT...CASS AND
MORGAIN FROM JACKSONVILLE SW. LOWS IN THE LOW TO MID 20S EXPECT
SOME UPPER TEENS FROM GALESBURG TO JACKSONVILLE WEST. NW WINDS
5-10 MPH TURNING LIGHT NNW LATER TONIGHT.
OVERCAST LOW CLOUDS FROM 1.5-3K FT BLANKET MUCH OF CENTRAL AND NE
IL INTO SE IA/WI AT MID EVENING WITH CLEARING SW OF JACKSONVILLE.
CLOUD LAYER IS ABOUT 1-2 K FT THICK PER KILX/KDVN SOUNDINGS AND
PILOT REPORTS THIS EVENING. 00Z KILX SOUNDING SHOWS STRONG
INVERSION FROM JUST ABOVE 900 MB TO 750 MB SO THIS IS TRAPPING LOW
LEVEL MOISTURE/CLOUDS OVER CENTRAL/SE IL TONIGHT WITH LIGHTER
FLOW. RAP MODEL 925-850 MB RH CAPTURING THIS CLOUD FIELD WELL
WHICH KEEPS ABUNDANT LOW CLOUDS OVER CENTRAL AND SE THROUGH THE
NIGHT WITH SOME DECREASING OF LOW CLOUDS FROM PEORIA TO
TAYLORVILLE LATER TONIGHT AND INTO EASTERN IL DURING THU MORNING
AS 1030 MB HIGH PRESSURE RIDGE OVER MN INTO CENTRAL IA/MO DRIFTS
EAST ACROSS THE MS VALLEY INTO IL THU. A LIGHT FOG COULD DEVELOP
OVER WEST CENTRAL AND NW IL LATER TONIGHT WHERE LESS LOW CLOUDS AND
LIGHTER NNW WINDS PREVAIL.
07
&&
.AVIATION...
ISSUED 555 PM CST WED MAR 6 2013
MVFR BROKEN TO OVERCAST CEILINGS WILL CONTINUE ACROSS THE CENTRAL
IL AIRPORTS MOST OF TONIGHT. USED HRRR AND RAP MODELS FOR TIMING
OF LOW CLOUDS BREAKING UP...FIRST AT SPI AFTER 09Z AND LAST AT CMI
AFTER 15Z. MODELS SHOWING INVERSION TRAPPING LOW LEVEL
CLOUDS/MOISTURE OVER CENTRAL IL TONIGHT AND LIKELY LINGERING OVER
EAST CENTRAL IL INTO THU MORNING. HAVE MVFR VSBYS WITH LIGHT FOG
LATE TONIGHT INTO THU MORNING AS LOW CLOUDS BREAK UP. NW WINDS
NEAR 10 KTS THIS EVENING WILL TURN NORTH AROUND 5 KTS LATER
TONIGHT INTO THU MORNING AS 1030 MB HIGH PRESSURE RIDGE OVER MN
AND WESTERN PARTS OF IA/MO DRIFTS EAST ACROSS THE MS RIVER VALLEY
AND INTO IL THU.
07
&&
.PREV DISCUSSION...
ISSUED 231 PM CST WED MAR 6 2013
MODELS IN REASONABLE AGREEMENT OVER THE 7-DAY PERIOD...PARTICULARLY
GIVEN THE PRIMARY ENERGY TO IMPACT ILLINOIS THIS WEEKEND IS
RELATIVELY POORLY SAMPLED OFF THE PACIFIC COAST.
SHORT TERM...TONIGHT THROUGH SATURDAY
STORM SYSTEM THAT BROUGHT SNOW TO FORECAST AREA YESTERDAY IS NOW
ALONG THE MID-ATLANTIC COAST AND CONTINUES TO DIMINISH ITS IMPACT ON
ILLINOIS AS HIGH PRESSURE OVER MID-MISSOURI VALLEY PUSHES EASTWARD.
PLENTIFUL CLOUDINESS PERSISTS TO THE EAST OF THE RIDGE AXIS AND
WILL ONLY GRADUALLY DIMINISH AS THE RIDGE PUSHES EAST TONIGHT.
WILL HAVE TO MONITOR CLOSELY AS DEVELOPING BREAKS MAY LEAD TO
LOWER TEMPS THAN FORECAST IN SNOW COVERED AREAS AS WELL AS A
POTENTIAL FOR FOG...PARTICULARLY WESTERN COUNTIES.
THERE HAS BEEN SOME SNOW MELT/COMPACTION TODAY IN OCCASIONAL SUNSHINE
DESPITE THE COLD TEMPERATURES. HAVE TEMPERED TOMORROWS HIGH
FORECAST A TAD GIVEN THE IMPACT OF THE REMAINING SNOW...BUT WITH
MARCH SUN AND RAPIDLY RISING 850 TEMPS...FEEL SNOW MAY ONLY HAVE A
MINOR IMPACT ON FRIDAYS TEMPS AND SHOULD BE GONE BY SATURDAY. WITH
LIGHT WINDS IN PLACE WITH DEEP RIDGING WILL HAVE TO MONITOR
CONDITIONS FOR POTENTIAL OF FOG BOTH THURSDAY AND FRIDAY NIGHTS.
BY SATURDAY AFTERNOON SOUTHEAST WINDS AND 850 TEMPERATURES
INCREASING TO AROUND 10C SHOULD SUPPORT HIGHS REACHING INTO THE
50S.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
STRONG SYSTEM CURRENTLY OFF THE NW PACIFIC COAST IS PROGGED TO PLUNGE
INTO THE SW U.S. AND THEN APPROACH ILLINOIS BY SATURDAY NIGHT.
WITH THIS SHIFT TO MORE OF PACIFIC STORM TRACK...PRECIP WITH THIS
NEXT SYSTEM SHOULD BE MOSTLY RAIN. ENERGY IS EXPECTED TO BE
EJECTED TOWARD US IN A PIECEMEAL FASHION PROVIDING US WITH SEVERAL
WAVES OF PRECIP INTO MONDAY. RAINFALL AMOUNTS MAY BE
SIGNIFICANT...PARTICULARLY IN OUR NORTHERN COUNTIES WHERE SNOWMELT
RUNOFF WILL CONTRIBUTE. PRECIP WATER FORECASTS FROM THE GFS HAVE
VALUES AS HIGH AS 1.15 INCHES LATE SATURDAY NIGHT WHICH IS 2+ SD
ABOVE NORMAL FOR MARCH. TOTAL 48-HOUR AMOUNTS MAY LOCALLY APROACH
2 INCHES.
SOME COLDER AIR FILTERS IN BEHIND THE LOW ON MONDAY...BUT BOUNDARY
LAYER TEMPS AT THIS POINT SUGGEST THAT THE PRECIP MAY ONLY
BRIEFLY MIX WITH OR CHANGE TO SNOW BEFORE ENDING.
IN WAKE OF SYSTEM...TEMPS SHOULD BE 5-10 DEGREES BELOW NORMAL
THROUGH WEDNESDAY. COLDER TEMPS SHOULD REMAIN NORTH OF THE AREA
WITH HIGH ZONAL COMPONENT UPPER LEVEL FLOW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
859 PM CST WED MAR 6 2013
.DISCUSSION...
ISSUED 900 PM CST WED MAR 6 2013
UPDATED THE FORECAST TO KEEP LOW CLOUDS IN THE FORECAST LONGER
TONIGHT AND ALSO NUDGE LOW TEMPERATURES UP A BIT DUE TO LINGERING
LOW CLOUDS. MOSTLY CLOUDY TO OVERCAST SKIES TONIGHT EXCEPT LESS
CLOUD COVER OVER 4 SW COUNTIES OF SCHUYLER...SCOTT...CASS AND
MORGAIN FROM JACKSONVILLE SW. LOWS IN THE LOW TO MID 20S EXPECT
SOME UPPER TEENS FROM GALESBURG TO JACKSONVILLE WEST. NW WINDS
5-10 MPH TURNING LIGHT NNW LATER TONIGHT.
OVERCAST LOW CLOUDS FROM 1.5-3K FT BLANKET MUCH OF CENTRAL AND NE
IL INTO SE IA/WI AT MID EVENING WITH CLEARING SW OF JACKSONVILLE.
CLOUD LAYER IS ABOUT 1-2 K FT THICK PER KILX/KDVN SOUNDINGS AND
PILOT REPORTS THIS EVENING. 00Z KILX SOUNDING SHOWS STRONG
INVERSION FROM JUST ABOVE 900 MB TO 750 MB SO THIS IS TRAPPING LOW
LEVEL MOISTURE/CLOUDS OVER CENTRAL/SE IL TONIGHT WITH LIGHTER
FLOW. RAP MODEL 925-850 MB RH CAPTURING THIS CLOUD FIELD WELL
WHICH KEEPS ABUNDANT LOW CLOUDS OVER CENTRAL AND SE THROUGH THE
NIGHT WITH SOME DECREASING OF LOW CLOUDS FROM PEORIA TO
TAYLORVILLE LATER TONIGHT AND INTO EASTERN IL DURING THU MORNING
AS 1030 MB HIGH PRESSURE RIDGE OVER MN INTO CENTRAL IA/MO DRIFTS
EAST ACROSS THE MS VALLEY INTO IL THU.
07
&&
.AVIATION...
ISSUED 555 PM CST WED MAR 6 2013
MVFR BROKEN TO OVERCAST CEILINGS WILL CONTINUE ACROSS THE CENTRAL
IL AIRPORTS MOST OF TONIGHT. USED HRRR AND RAP MODELS FOR TIMING
OF LOW CLOUDS BREAKING UP...FIRST AT SPI AFTER 09Z AND LAST AT CMI
AFTER 15Z. MODELS SHOWING INVERSION TRAPPING LOW LEVEL
CLOUDS/MOISTURE OVER CENTRAL IL TONIGHT AND LIKELY LINGERING OVER
EAST CENTRAL IL INTO THU MORNING. HAVE MVFR VSBYS WITH LIGHT FOG
LATE TONIGHT INTO THU MORNING AS LOW CLOUDS BREAK UP. NW WINDS
NEAR 10 KTS THIS EVENING WILL TURN NORTH AROUND 5 KTS LATER
TONIGHT INTO THU MORNING AS 1030 MB HIGH PRESSURE RIDGE OVER MN
AND WESTERN PARTS OF IA/MO DRIFTS EAST ACROSS THE MS RIVER VALLEY
AND INTO IL THU.
07
&&
.PREV DISCUSSION...
ISSUED 231 PM CST WED MAR 6 2013
MODELS IN REASONABLE AGREEMENT OVER THE 7-DAY PERIOD...PARTICULARLY
GIVEN THE PRIMARY ENERGY TO IMPACT ILLINOIS THIS WEEKEND IS
RELATIVELY POORLY SAMPLED OFF THE PACIFIC COAST.
SHORT TERM...TONIGHT THROUGH SATURDAY
STORM SYSTEM THAT BROUGHT SNOW TO FORECAST AREA YESTERDAY IS NOW
ALONG THE MID-ATLANTIC COAST AND CONTINUES TO DIMINISH ITS IMPACT ON
ILLINOIS AS HIGH PRESSURE OVER MID-MISSOURI VALLEY PUSHES EASTWARD.
PLENTIFUL CLOUDINESS PERSISTS TO THE EAST OF THE RIDGE AXIS AND
WILL ONLY GRADUALLY DIMINISH AS THE RIDGE PUSHES EAST TONIGHT.
WILL HAVE TO MONITOR CLOSELY AS DEVELOPING BREAKS MAY LEAD TO
LOWER TEMPS THAN FORECAST IN SNOW COVERED AREAS AS WELL AS A
POTENTIAL FOR FOG...PARTICULARLY WESTERN COUNTIES.
THERE HAS BEEN SOME SNOW MELT/COMPACTION TODAY IN OCCASIONAL SUNSHINE
DESPITE THE COLD TEMPERATURES. HAVE TEMPERED TOMORROWS HIGH
FORECAST A TAD GIVEN THE IMPACT OF THE REMAINING SNOW...BUT WITH
MARCH SUN AND RAPIDLY RISING 850 TEMPS...FEEL SNOW MAY ONLY HAVE A
MINOR IMPACT ON FRIDAYS TEMPS AND SHOULD BE GONE BY SATURDAY. WITH
LIGHT WINDS IN PLACE WITH DEEP RIDGING WILL HAVE TO MONITOR
CONDITIONS FOR POTENTIAL OF FOG BOTH THURSDAY AND FRIDAY NIGHTS.
BY SATURDAY AFTERNOON SOUTHEAST WINDS AND 850 TEMPERATURES
INCREASING TO AROUND 10C SHOULD SUPPORT HIGHS REACHING INTO THE
50S.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
STRONG SYSTEM CURRENTLY OFF THE NW PACIFIC COAST IS PROGGED TO PLUNGE
INTO THE SW U.S. AND THEN APPROACH ILLINOIS BY SATURDAY NIGHT.
WITH THIS SHIFT TO MORE OF PACIFIC STORM TRACK...PRECIP WITH THIS
NEXT SYSTEM SHOULD BE MOSTLY RAIN. ENERGY IS EXPECTED TO BE
EJECTED TOWARD US IN A PIECEMEAL FASHION PROVIDING US WITH SEVERAL
WAVES OF PRECIP INTO MONDAY. RAINFALL AMOUNTS MAY BE
SIGNIFICANT...PARTICULARLY IN OUR NORTHERN COUNTIES WHERE SNOWMELT
RUNOFF WILL CONTRIBUTE. PRECIP WATER FORECASTS FROM THE GFS HAVE
VALUES AS HIGH AS 1.15 INCHES LATE SATURDAY NIGHT WHICH IS 2+ SD
ABOVE NORMAL FOR MARCH. TOTAL 48-HOUR AMOUNTS MAY LOCALLY APROACH
2 INCHES.
SOME COLDER AIR FILTERS IN BEHIND THE LOW ON MONDAY...BUT BOUNDARY
LAYER TEMPS AT THIS POINT SUGGEST THAT THE PRECIP MAY ONLY
BRIEFLY MIX WITH OR CHANGE TO SNOW BEFORE ENDING.
IN WAKE OF SYSTEM...TEMPS SHOULD BE 5-10 DEGREES BELOW NORMAL
THROUGH WEDNESDAY. COLDER TEMPS SHOULD REMAIN NORTH OF THE AREA
WITH HIGH ZONAL COMPONENT UPPER LEVEL FLOW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
556 PM CST WED MAR 6 2013
.DISCUSSION...
ISSUED 231 PM CST WED MAR 6 2013
MODELS IN REASONABLE AGREEMENT OVER THE 7-DAY PERIOD...PARTICULARLY
GIVEN THE PRIMARY ENERGY TO IMPACT ILLINOIS THIS WEEKEND IS
RELATIVELY POORLY SAMPLED OFF THE PACIFIC COAST.
SHORT TERM...TONIGHT THROUGH SATURDAY
STORM SYSTEM THAT BROUGHT SNOW TO FORECAST AREA YESTERDAY IS NOW
ALONG THE MID-ATLANTIC COAST AND CONTINUES TO DIMINISH ITS IMPACT ON
ILLINOIS AS HIGH PRESSURE OVER MID-MISSOURI VALLEY PUSHES EASTWARD.
PLENTIFUL CLOUDINESS PERSISTS TO THE EAST OF THE RIDGE AXIS AND
WILL ONLY GRADUALLY DIMINISH AS THE RIDGE PUSHES EAST TONIGHT.
WILL HAVE TO MONITOR CLOSELY AS DEVELOPING BREAKS MAY LEAD TO
LOWER TEMPS THAN FORECAST IN SNOW COVERED AREAS AS WELL AS A
POTENTIAL FOR FOG...PARTICULARLY WESTERN COUNTIES.
THERE HAS BEEN SOME SNOW MELT/COMPACTION TODAY IN OCCASIONAL SUNSHINE DESPITE
THE COLD TEMPERATURES. HAVE TEMPERED TOMORROWS HIGH FORECAST A TAD
GIVEN THE IMPACT OF THE REMAINING SNOW...BUT WITH MARCH SUN AND
RAPIDLY RISING 850 TEMPS...FEEL SNOW MAY ONLY HAVE A MINOR IMPACT
ON FRIDAYS TEMPS AND SHOULD BE GONE BY SATURDAY. WITH LIGHT WINDS
IN PLACE WITH DEEP RIDGING WILL HAVE TO MONITOR CONDITIONS FOR
POTENTIAL OF FOG BOTH THURSDAY AND FRIDAY NIGHTS.
BY SATURDAY AFTERNOON SOUTHEAST WINDS AND 850 TEMPERATURES
INCREASING TO AROUND 10C SHOULD SUPPORT HIGHS REACHING INTO THE
50S.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
STRONG SYSTEM CURRENTLY OFF THE NW PACIFIC COAST IS PROGGED TO PLUNGE
INTO THE SW U.S. AND THEN APPROACH ILLINOIS BY SATURDAY NIGHT.
WITH THIS SHIFT TO MORE OF PACIFIC STORM TRACK...PRECIP WITH THIS
NEXT SYSTEM SHOULD BE MOSTLY RAIN. ENERGY IS EXPECTED TO BE
EJECTED TOWARD US IN A PIECEMEAL FASHION PROVIDING US WITH SEVERAL
WAVES OF PRECIP INTO MONDAY. RAINFALL AMOUNTS MAY BE
SIGNIFICANT...PARTICULARLY IN OUR NORTHERN COUNTIES WHERE SNOWMELT
RUNOFF WILL CONTRIBUTE. PRECIP WATER FORECASTS FROM THE GFS HAVE
VALUES AS HIGH AS 1.15 INCHES LATE SATURDAY NIGHT WHICH IS 2+ SD
ABOVE NORMAL FOR MARCH. TOTAL 48-HOUR AMOUNTS MAY LOCALLY APROACH
2 INCHES.
SOME COLDER AIR FILTERS IN BEHIND THE LOW ON MONDAY...BUT BOUNDARY
LAYER TEMPS AT THIS POINT SUGGEST THAT THE PRECIP MAY ONLY
BRIEFLY MIX WITH OR CHANGE TO SNOW BEFORE ENDING.
IN WAKE OF SYSTEM...TEMPS SHOULD BE 5-10 DEGREES BELOW NORMAL
THROUGH WEDNESDAY. COLDER TEMPS SHOULD REMAIN NORTH OF THE AREA
WITH HIGH ZONAL COMPONENT UPPER LEVEL FLOW.
&&
.AVIATION...
ISSUED 555 PM CST WED MAR 6 2013
MVFR BROKEN TO OVERCAST CEILINGS WILL CONTINUE ACROSS THE CENTRAL
IL AIRPORTS MOST OF TONIGHT. USED HRRR AND RAP MODELS FOR TIMING
OF LOW CLOUDS BREAKING UP...FIRST AT SPI AFTER 09Z AND LAST AT CMI
AFTER 15Z. MODELS SHOWING INVERSION TRAPPING LOW LEVEL
CLOUDS/MOISTURE OVER CENTRAL IL TONIGHT AND LIKELY LINGERING OVER
EAST CENTRAL IL INTO THU MORNING. HAVE MVFR VSBYS WITH LIGHT FOG
LATE TONIGHT INTO THU MORNING AS LOW CLOUDS BREAK UP. NW WINDS
NEAR 10 KTS THIS EVENING WILL TURN NORTH AROUND 5 KTS LATER
TONIGHT INTO THU MORNING AS 1030 MB HIGH PRESSURE RIDGE OVER MN
AND WESTERN PARTS OF IA/MO DRIFTS EAST ACROSS THE MS RIVER VALLEY
AND INTO IL THU.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
306 AM CST TUE MAR 5 2013
.DISCUSSION...
753 PM CST
MADE A FEW MINOR ADJUSTMENTS TO THE FORECAST OVERNIGHT REGARDING
THE ONSET OF PRECIP. SCATTERED LIGHT SNOW SHOWERS ARE ACROSS
MINNESOTA...WISCONSIN...AND IOWA AHEAD OF THE LOW PRESSURE SYSTEM.
WITH SLIGHTLY DRIER AIR OVER NORTHERN IL...NOT EXPECTING MUCH
SNOWFALL FROM THESE SNOW SHOWERS AS THEY MOVE INTO OUR AREA. IN
FACT NUMEROUS AREAS UNDER THE REFLECTIVITIES TO OUR WEST ARE NOT
REPORTING ANY PRECIP AT THE SFC. REDUCED POPS TO SLIGHT CHANCE
THROUGH MIDNIGHT WITH LITTLE TO NO SNOW EXPECTED.
THE SYSTEM IS MOVING A LITTLE SLOWER THAN EARLIER THOUGHT SO ALSO
LOWERED POPS BTWN MIDNIGHT AND 3AM TO CHANCE OR LESS. HRRR AND OUR
IN HOUSE ARW BOTH INDICATE SNOW WILL NOT REACH CENTRAL IL UNTIL
LATE TONIGHT AFTER 3AM. DID NOT GO AS SLOW AS THEY INDICATED AS
THE ATMOSPHERE COULD BECOME MORE SATURATED BY LIGHT FLURRIES
OVERNIGHT.
OTHERWISE THE GOING FORECAST LOOKS ON TRACK WITH THE HEAVIEST
SNOWFALL STILL EXPECTED FROM TOMORROW MORNING THROUGH THE EVENING
HOURS. NO CHANGES WERE MADE TO THE WINTER STORM WARNING. TRAVEL
WILL BE SEVERELY IMPACTED BY SNOWFALL RATES OF 1-2 INCHES PER HOUR
AND LOW VISIBILITIES. WINDS INCREASE TOMORROW EVENING AND BLOWING
SNOW TUESDAY EVENING AND OVERNIGHT WILL LIKELY REDUCE VISIBILITIES
TO A QUARTER MILE OR LESS AT TIMES.
JEE
//PREV DISCUSSION...
315 PM CST
SHORT RANGE...TONIGHT THROUGH TUESDAY NIGHT...
HAVE DECIDED TO ISSUE A WINTER STORM WARNING FOR THE REST OF MY
COUNTIES FOR LATE TONIGHT THROUGH TUESDAY EVENING.
NOT MUCH HAS CHANGED FROM THE PREVIOUS THINKING. THE LATEST WATER
VAPOR IMAGERY PLACES THE CENTER OF THIS SYSTEM ACROSS THE DAKOTAS
THIS AFTERNOON. WARM AIR ADVECTION/ISENTROPIC ASCENT AHEAD OF THIS
FEATURE HAS LEAD TO A WEAK BAND OF MAINLY LIGHT SNOW AND FLURRIES
ACROSS THE AREA THIS AFTERNOON. THIS HAS NOT AMOUNTED TO MUCH AND
LIKELY WILL NOT THROUGH THIS EVENING. THE MAIN SHOW WILL GET GOING
LATE TONIGHT AND ON TUESDAY. THE GUIDANCE HAS DISAGREEMENTS ON THE
EXACT TIMING OF THE ONSET OF PRECIP...WITH THE ECMWF AND NAM
SUGGESTING THAT THE SNOW MAY HOLD OFF UNTIL DAYBREAK. I DID BACK
OFF ON POPS A BIT TONIGHT TO ACCOUNT FOR A LATER ONSET...BUT STILL
MENTION LIKELY POPS TOWARDS DAYBREAK.
ONCE THINGS GET GOING TUESDAY MORNING...IT APPEARS THE SNOW INCREASE
IN INTENSITY THROUGH THE LATE MORNING AND DURING THE AFTERNOON.
IMPRESSIVE FORCING FOR ASCENT IS PROGGED TO SET UP IN THE DENDRITIC
GROWTH ZONE DURING THE AFTERNOON AS ISENTROPIC ASCENT INCREASES
AHEAD THE APPROACHING MID LEVEL SYSTEM. IT ALSO APPEARS THAT A TROWAL
LIKE STRUCTURE WILL DEVELOP ACROSS THE REGION DURING THE AFTERNOON
AS THE 700 MB LOW TRACKS SOUTHEASTWARD FROM EASTERN IOWA AND ACROSS
CENTRAL ILLINOIS. THIS WILL LIKELY LEAD TO A DECENT BAND OF MID
LEVEL FRONTOGENESIS FROM NORTH-NORTHWEST TO SOUTH-SOUTHEAST RIGHT
ACROSS THE CWA. AS IT TYPICAL WITH THIS TYPE OF SETUP...LOW STATIC
STABILITY SETS UP IN THE MID LEVELS DUE TO STEEP LAPSE RATES. LOOKS
TO SET UP THE INGREDIENTS FOR PERIODS OF HEAVY SNOW ACROSS THE AREA
DURING THE AFTERNOON WITH SNOW RATES OF 1 TO 1.5 INCHES AT TIMES.
I STILL DO HAVE SOME CONCERNS FOR PRECIPITATION TYPES ACROSS MY
SOUTHERN COUNTIES INITIALLY TUESDAY MORNING. GUIDANCE CONTINUES TO
SUGGEST THAT ENOUGH WARM AIR MAY BE SQUEEZED NORTHWARD ACROSS
CENTRAL ILLINOIS TO RESULT IN SOME RAIN OR SLEET AND SNOW MIX
THROUGH MID TO LATE MORNING. THEREAFTER...STRONG DYNAMIC COOLING
ASSOCIATED WITH MID LEVEL HEIGHT FALLS AND STRONG ASCENT...SHOULD
LEAD TO ALL SNOW DURING THE AFTERNOON. ALTHOUGH SNOW TO LIQUID
RATIOS MAY ONLY BE 10:1 FOR A PERIOD FAR SOUTH...IT APPEARS THAT
HEAVY SNOW COULD STILL RESULT IN 6 OR MORE INCHES ACROSS THESE
AREAS...AND THEREFORE HAVE INCLUDED THEM IN THE WARNING.
SOME OF THE GUIDANCE HAS SHIFTED THE HEAVIEST PRECIP AXIS JUST A TAD
SOUTH. HOWEVER...WITH LAKE ENHANCEMENT LIKELY TUESDAY AFTERNOON AND
EVENING...PERIODS OF HEAVY SNOW STILL APPEARS TO BE A GOOD BET
ACROSS FAR NORTHEAST ILLINOIS.
WINDS WILL INCREASE OUT OF THE NORTH-NORTHEAST LATE TUESDAY AFTERNOON
AND NIGHT AS THE LOW DEEPENS ACROSS THE OHIO VALLEY. THESE WINDS
COULD GUST UP TO 30-35 MPH...RESULTING IN SOME BLOWING AND DRIFTING
SNOW. I ADDED BLOWING SNOW AREA-WIDE BY TUESDAY EVENING TO ACCOUNT
FOR THIS.
SNOW SHOULD BEGIN TO TAPPER OFF FROM WEST TO EAST ACROSS THE AREA
DURING THE EVENING ON TUESDAY. HOWEVER...SOME MODERATE TO HEAVY SNOW
MAY CONTINUE INTO THE LATER EVENING HOURS...ESPECIALLY ACROSS
EASTERN ILLINOIS AND INTO INDIANA. HOWEVER...SNOWFALL RATES SHOULD
DROP OFF SIGNIFICANTLY AFTER 06 UTC ON WEDNESDAY...WITH ONLY SOME
LAKE EFFECT SNOW SHOWERS CONTINUING INTO WEDNESDAY.
KJB
LONGER RANGE...WEDNESDAY THROUGH NEXT MONDAY...
THE MAIN CONCERNS BEYOND THE EARLY WEEK WINTER STORM INCLUDE THE
POTENTIAL FOR SOME LINGERING LAKE EFFECT SNOW WEDNESDAY INTO EARLY
THURSDAY...THEN AFTER A COUPLE OF QUIET DAYS A WARM-UP WITH THE
POTENTIAL FOR RAIN ARRIVES LATER IN THE WEEKEND AND EARLY NEXT WEEK.
STRONG UPPER/SURFACE LOWS ASSOCIATED WITH THE DEPARTING WINTER STORM
SYSTEM SHOULD BE DIGGING WELL OFF TO OUR SOUTHEAST ACROSS THE
CENTRAL/SOUTHERN APPALACHIANS AND OFF THE MID-ATLANTIC COAST
WEDNESDAY. GUIDANCE DOES DEPICT A RAPIDLY SHEARING/WEAKENING
MID-LEVEL VORT MOVING ACROSS THE AREA DURING THE MORNING HOURS...
THOUGH OVERALL RISING HEIGHTS/DEVELOPING UPPER RIDGING IS INDICATED
WITH LOW LEVEL COLD ADVECTION AND DECREASING CYCLONIC CURVATURE.
THIS PRODUCES SUBSIDENCE AND DRYING ABOVE THE BOUNDARY LAYER... WITH
LITTLE/NO SYNOPTIC SCALE FORCING FOR LINGERING PRECIP. WITHIN THE
BOUNDARY LAYER HOWEVER...NORTH-NORTHEAST FLOW DOWN LAKE MICHIGAN
PRODUCES LONG FETCH AND FAIRLY STRONG MOISTURE-CONVERGENCE ALONG THE
WEST/SOUTHWEST SHORE. THERMODYNAMIC PROFILES BASED ON 12Z WRF-NAM
AND GFS SHOW RELATIVELY MARGINAL SETUP FOR ORGANIZED SNOW SHOWERS
HOWEVER...WITH 850 MB TEMPS ONLY AROUND -8/9C WEDNESDAY AND
WEDNESDAY NIGHT. THIS YIELDS WATER SFC TO 850 MB DELTA T VALUES
AROUND 12/13...WITH COMPUTED EQUILIBRIUM LEVELS LESS THAN 5000 FT
AGL. WHILE SUFFICIENT TO PRODUCE LAKE EFFECT CLOUDS AND LIGHT SNOW
SHOWERS...THESE PARAMETERS SUGGEST IT WOULD BE DIFFICULT TO GET ANY
SIGNIFICANT ACCUMULATION UNLESS SNOW BAND WERE STATIONARY FOR A LONG
PERIOD OF TIME. LOW LEVEL WIND PROFILES INDICATE THAT CONVERGENCE
WILL FAVOR THE ILLINOIS SHORE INTO LAKE COUNTY INDIANA THROUGH
WEDNESDAY EVENING...THUS HAVE INDICATED SOME MINOR ACCUMULATION OF A
FEW TENTHS OF AN INCH THERE. IF STRONGER THERMODYNAMICS WERE TO
OCCUR OR THE BAND WERE TO EXPERIENCE A HIGHER RESIDENCE TIME IN ANY
ONE LOCATION PERHAPS AN INCH OR TWO COULD ACCUMULATE...THOUGH
CONFIDENCE IN THAT OCCURRING IS VERY LOW. HIGH PRESSURE RIDGE
SPREADS EAST ACROSS THE MISSISSIPPI VALLEY LATER WEDNESDAY NIGHT AND
THURSDAY...WHICH LEADS TO WINDS WEAKENING AND VEERING NORTHEAST
THURSDAY MORNING AND THEN EAST LATER IN THE DAY WITH THERMODYNAMIC
SETUP ALSO WEAKENING RAPIDLY BEYOND THURSDAY MORNING.
PERIOD OF QUIET WEATHER IS THEN ANTICIPATED AS UPPER RIDGE BUILDS
ACROSS THE CENTRAL CONUS...AND SURFACE HIGH PRESSURE RIDGE MOVES
SLOWLY ACROSS THE AREA INTO FRIDAY. TEMPERATURES MODERATE BACK
TOWARD NORMAL...THOUGH DEEP SNOW COVER FROM EARLY WEEK STORM WILL
TEMPER THINGS FOR SEVERAL DAYS. BLEND OF 925-950 TEMPS AND MOS USED
FOR TEMPS...THOUGH LEANED TOWARD COOLER ECMWF MINS WHERE SKIES
ACCOUNT SNOW COVER.
BEYOND FRIDAY...GUIDANCE IN GENERALLY GOOD AGREEMENT IN CONTINUING
TO SLOWLY MOVE UPPER RIDGE EAST ACROSS THE REGION INTO
SATURDAY...WHILE DEVELOPING UPPER LOW OVER THE SOUTHWESTERN CONUS
AND THEN SLOWLY LIFTING IT NORTHEAST ACROSS THE PLAINS. NEW 12Z
ECMWF REALLY SLOWS THINGS DOWN OVER PREVIOUS RUNS...AND ENDS UP
CUTTING OFF THE LOW OVER THE HIGH PLAINS INTO EARLY NEXT WEEK WHILE
ITS PREVIOUS RUN AND OTHER GLOBAL GUIDANCE LIFT IT NORTHEAST ACROSS
THE REGION MONDAY. WHILE SLOWER MAY VERY WELL END UP BETTER...HAVE
BASED EXTENDED PART OF FORECAST ON BETTER CONSENSUS AND AWAY FROM
12Z ECMWF. OVERALL THIS SUGGEST PRECIP THREAT EVENTUALLY INCREASES
SATURDAY NIGHT/SUNDAY AND MONDAY AS OCCLUDING LOW MOVES THROUGH THE
AREA. THICKNESS FIELDS/SOUNDINGS SUGGEST THIS SHOULD MAINLY BE A
RAIN EVENT FOR OUR AREA...WITH TEMPS INTO THE 40S/LOWER 50S BY
SUNDAY/MONDAY. WILL HAVE TO MONITOR HYDRO ISSUES AS THIS STORM
APPROACHES...AS WE WILL BE MELTING OFF THE DEEP EARLY WEEK SNOW PACK
AND THEN POTENTIALLY RAINING 0.5-1.00 INCHES OF RAIN BY THE
SUNDAY/MONDAY TIMEFRAME.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* HEAVY SNOW DURING THE AFTERNOON/EVENING HOURS.
* GUSTY NORTHEAST/NORTH WINDS CAUSING BLOWING SNOW.
BMD
//DISCUSSION...UPDATED 06Z...
OVERNIGHT...BROAD SCALE WEAK BUT PERSISTENT ASCENT WILL GRADUALLY
SATURATE THE ATMOSPHERE TOP DOWN WITH CIGS FALLING TO MVFR AND LIGHT
SNOW LIKELY STARTING AROUND THE SAME TIME. THIS DOWNWARD TREND HAS
BEEN OCCURRING SLOWER THAN ORIGINALLY THOUGHT...SO ADJUSTED TIMING
ACCORDINGLY...WITH THE EXPECTATION FOR MVFR CIGS/LIGHT SNOW TO BEGIN
AROUND OR SHORTLY BEFORE DAYBREAK TUESDAY.
MODELS CONTINUE TO BE IN GOOD AGREEMENT REGARDING THE POTENTIAL FOR
HEAVY SNOW...POINTING AT THE AFTERNOON TO EARLY EVENING HOURS HAVING
THE WORST CONDITIONS. DONT HAVE THE BEST CONFIDENCE REGARDING 1/4SM
PREVAILING FOR SUCH A LONG PERIOD...ESPECIALLY SINCE ITS BELOW
MET/MAV LOWEST GUIDANCE...BUT THINK THAT KEEPING TEMPO 1/4SM IS
STILL A GOOD CALL AS PERIODS OF HEAVY SNOW ARE LIKELY. STRONG
FORCING EARLY IN THE AFTERNOON IS CENTERED WELL WITHIN THE DENDRITIC
GROWTH ZONE LEADING TO EFFICIENT SNOW PRODUCTION AND SNOWFALL RATES
IN EXCESS OF AN INCH PER HOUR AT TIMES. LATER IN THE EVENING...THE
DGZ DEEPENS...AND DESPITE THE FORCING BECOMING SOMEWHAT
OFFSET...FEEL THE POTENTIAL FOR LESS THAN 1SM VSBY HEAVY SNOW
CONTINUES. IN ADDITION...VERY SHALLOW INSTABILITY DEVELOPS OVER LAKE
MICHIGAN LATE IN THE AFTERNOON AND EARLY EVENING WHICH MAY HELP TO
ENHANCE SNOWFALL IN THE CHICAGO AREA. NORTHEAST WINDS WILL BEGIN TO
INCREASE EVENING AS THE GRADIENT TIGHTENS AS STRONG PRESSURE RISES
TRANSLATE EAST ACROSS THE AREA. THIS WILL LEAD TO BLOWING SNOW AND
MAY FURTHER COMPLICATE VSBY FCST. CURRENT FORECAST IS FOR 7 TO 10
INCHES OF SNOW.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN CIG TRENDS THIS MORNING.
* HIGH CONFIDENCE IN HEAVY SNOW WITH PERIODS OF LESS THAN 1SM
VSBY...MEDIUM CONFIDENCE IN 1/4SM AT TIMES DURING THE
AFTERNOON...THOUGH LOW CONFIDENCE ON SPECIFIC TIMING/DURATION.
* MEDIUM TO HIGH CONFIDENCE IN WIND FORECAST.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z TUESDAY...UPDATED 00Z...
WEDNESDAY...MVFR.
THURSDAY AND FRIDAY...VFR.
SATURDAY...SLIGHT CHANCE RAIN.
SUNDAY...SLIGHT CHANCE RAIN WITH HIGHER CHANCE SUNDAY NIGHT. MVFR
POSSIBLE SUNDAY NIGHT.
MDB
&&
.MARINE...
302 AM CST
MAIN CONCERN FOR LAKE MICHIGAN WILL BE WINDS PICKING UP TO AROUND 30
KT TODAY AS LOW PRESSURE DEVELOPS ACROSS THE MIDWEST. WINDS ARE
EXPECTED TO PEAK THIS EVENING AS THE GRADIENT BECOMES TIGHTEST BEHIND
THE DEPARTING AREA OF LOW PRESSURE OVER THE UPPER OHIO VALLEY AND
MODEST PRESSURE RISES MOVE ACROSS SOUTHERN LAKE MICHIGAN. THE
THREAT FOR LOW END GALES SEEMS INCREASINGLY UNLIKELY FROM THIS
EVENT. SNOW IS LIKELY OVER SOUTHERN PORTIONS OF LAKE MICHIGAN
TODAY...WITH SOME LAKE ENHANCEMENT/LAKE EFFECT SHOWERS THIS
EVENING AND TONIGHT. HIGH PRESSURE WILL MOVE ACROSS THE LAKE
THURSDAY INTO FRIDAY ALLOWING CONDITIONS TO IMPROVE...BUT WINDS
FRESHEN UP AGAIN LATE IN THE WEEKEND AS ANOTHER AREA OF LOW
PRESSURE MOVES INTO THE MIDWEST. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL MIDNIGHT WEDNESDAY.
IN...WINTER STORM WARNING...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT WEDNESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 3 AM THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1154 PM CST MON MAR 4 2013
.DISCUSSION...
753 PM CST
MADE A FEW MINOR ADJUSTMENTS TO THE FORECAST OVERNIGHT REGARDING
THE ONSET OF PRECIP. SCATTERED LIGHT SNOW SHOWERS ARE ACROSS
MINNESOTA...WISCONSIN...AND IOWA AHEAD OF THE LOW PRESSURE SYSTEM.
WITH SLIGHTLY DRIER AIR OVER NORTHERN IL...NOT EXPECTING MUCH
SNOWFALL FROM THESE SNOW SHOWERS AS THEY MOVE INTO OUR AREA. IN
FACT NUMEROUS AREAS UNDER THE REFLECTIVITIES TO OUR WEST ARE NOT
REPORTING ANY PRECIP AT THE SFC. REDUCED POPS TO SLIGHT CHANCE
THROUGH MIDNIGHT WITH LITTLE TO NO SNOW EXPECTED.
THE SYSTEM IS MOVING A LITTLE SLOWER THAN EARLIER THOUGHT SO ALSO
LOWERED POPS BTWN MIDNIGHT AND 3AM TO CHANCE OR LESS. HRRR AND OUR
IN HOUSE ARW BOTH INDICATE SNOW WILL NOT REACH CENTRAL IL UNTIL
LATE TONIGHT AFTER 3AM. DID NOT GO AS SLOW AS THEY INDICATED AS
THE ATMOSPHERE COULD BECOME MORE SATURATED BY LIGHT FLURRIES
OVERNIGHT.
OTHERWISE THE GOING FORECAST LOOKS ON TRACK WITH THE HEAVIEST
SNOWFALL STILL EXPECTED FROM TOMORROW MORNING THROUGH THE EVENING
HOURS. NO CHANGES WERE MADE TO THE WINTER STORM WARNING. TRAVEL
WILL BE SEVERELY IMPACTED BY SNOWFALL RATES OF 1-2 INCHES PER HOUR
AND LOW VISIBILITIES. WINDS INCREASE TOMORROW EVENING AND BLOWING
SNOW TUESDAY EVENING AND OVERNIGHT WILL LIKELY REDUCE VISIBILITIES
TO A QUARTER MILE OR LESS AT TIMES.
JEE
//PREV DISCUSSION...
315 PM CST
SHORT RANGE...TONIGHT THROUGH TUESDAY NIGHT...
HAVE DECIDED TO ISSUE A WINTER STORM WARNING FOR THE REST OF MY
COUNTIES FOR LATE TONIGHT THROUGH TUESDAY EVENING.
NOT MUCH HAS CHANGED FROM THE PREVIOUS THINKING. THE LATEST WATER
VAPOR IMAGERY PLACES THE CENTER OF THIS SYSTEM ACROSS THE DAKOTAS
THIS AFTERNOON. WARM AIR ADVECTION/ISENTROPIC ASCENT AHEAD OF THIS
FEATURE HAS LEAD TO A WEAK BAND OF MAINLY LIGHT SNOW AND FLURRIES
ACROSS THE AREA THIS AFTERNOON. THIS HAS NOT AMOUNTED TO MUCH AND
LIKELY WILL NOT THROUGH THIS EVENING. THE MAIN SHOW WILL GET GOING
LATE TONIGHT AND ON TUESDAY. THE GUIDANCE HAS DISAGREEMENTS ON THE
EXACT TIMING OF THE ONSET OF PRECIP...WITH THE ECMWF AND NAM
SUGGESTING THAT THE SNOW MAY HOLD OFF UNTIL DAYBREAK. I DID BACK
OFF ON POPS A BIT TONIGHT TO ACCOUNT FOR A LATER ONSET...BUT STILL
MENTION LIKELY POPS TOWARDS DAYBREAK.
ONCE THINGS GET GOING TUESDAY MORNING...IT APPEARS THE SNOW INCREASE
IN INTENSITY THROUGH THE LATE MORNING AND DURING THE AFTERNOON.
IMPRESSIVE FORCING FOR ASCENT IS PROGGED TO SET UP IN THE DENDRITIC
GROWTH ZONE DURING THE AFTERNOON AS ISENTROPIC ASCENT INCREASES
AHEAD THE APPROACHING MID LEVEL SYSTEM. IT ALSO APPEARS THAT A TROWAL
LIKE STRUCTURE WILL DEVELOP ACROSS THE REGION DURING THE AFTERNOON
AS THE 700 MB LOW TRACKS SOUTHEASTWARD FROM EASTERN IOWA AND ACROSS
CENTRAL ILLINOIS. THIS WILL LIKELY LEAD TO A DECENT BAND OF MID
LEVEL FRONTOGENESIS FROM NORTH-NORTHWEST TO SOUTH-SOUTHEAST RIGHT
ACROSS THE CWA. AS IT TYPICAL WITH THIS TYPE OF SETUP...LOW STATIC
STABILITY SETS UP IN THE MID LEVELS DUE TO STEEP LAPSE RATES. LOOKS
TO SET UP THE INGREDIENTS FOR PERIODS OF HEAVY SNOW ACROSS THE AREA
DURING THE AFTERNOON WITH SNOW RATES OF 1 TO 1.5 INCHES AT TIMES.
I STILL DO HAVE SOME CONCERNS FOR PRECIPITATION TYPES ACROSS MY
SOUTHERN COUNTIES INITIALLY TUESDAY MORNING. GUIDANCE CONTINUES TO
SUGGEST THAT ENOUGH WARM AIR MAY BE SQUEEZED NORTHWARD ACROSS
CENTRAL ILLINOIS TO RESULT IN SOME RAIN OR SLEET AND SNOW MIX
THROUGH MID TO LATE MORNING. THEREAFTER...STRONG DYNAMIC COOLING
ASSOCIATED WITH MID LEVEL HEIGHT FALLS AND STRONG ASCENT...SHOULD
LEAD TO ALL SNOW DURING THE AFTERNOON. ALTHOUGH SNOW TO LIQUID
RATIOS MAY ONLY BE 10:1 FOR A PERIOD FAR SOUTH...IT APPEARS THAT
HEAVY SNOW COULD STILL RESULT IN 6 OR MORE INCHES ACROSS THESE
AREAS...AND THEREFORE HAVE INCLUDED THEM IN THE WARNING.
SOME OF THE GUIDANCE HAS SHIFTED THE HEAVIEST PRECIP AXIS JUST A TAD
SOUTH. HOWEVER...WITH LAKE ENHANCEMENT LIKELY TUESDAY AFTERNOON AND
EVENING...PERIODS OF HEAVY SNOW STILL APPEARS TO BE A GOOD BET
ACROSS FAR NORTHEAST ILLINOIS.
WINDS WILL INCREASE OUT OF THE NORTH-NORTHEAST LATE TUESDAY AFTERNOON
AND NIGHT AS THE LOW DEEPENS ACROSS THE OHIO VALLEY. THESE WINDS
COULD GUST UP TO 30-35 MPH...RESULTING IN SOME BLOWING AND DRIFTING
SNOW. I ADDED BLOWING SNOW AREA-WIDE BY TUESDAY EVENING TO ACCOUNT
FOR THIS.
SNOW SHOULD BEGIN TO TAPPER OFF FROM WEST TO EAST ACROSS THE AREA
DURING THE EVENING ON TUESDAY. HOWEVER...SOME MODERATE TO HEAVY SNOW
MAY CONTINUE INTO THE LATER EVENING HOURS...ESPECIALLY ACROSS
EASTERN ILLINOIS AND INTO INDIANA. HOWEVER...SNOWFALL RATES SHOULD
DROP OFF SIGNIFICANTLY AFTER 06 UTC ON WEDNESDAY...WITH ONLY SOME
LAKE EFFECT SNOW SHOWERS CONTINUING INTO WEDNESDAY.
KJB
LONGER RANGE...WEDNESDAY THROUGH NEXT MONDAY...
THE MAIN CONCERNS BEYOND THE EARLY WEEK WINTER STORM INCLUDE THE
POTENTIAL FOR SOME LINGERING LAKE EFFECT SNOW WEDNESDAY INTO EARLY
THURSDAY...THEN AFTER A COUPLE OF QUIET DAYS A WARM-UP WITH THE
POTENTIAL FOR RAIN ARRIVES LATER IN THE WEEKEND AND EARLY NEXT WEEK.
STRONG UPPER/SURFACE LOWS ASSOCIATED WITH THE DEPARTING WINTER STORM
SYSTEM SHOULD BE DIGGING WELL OFF TO OUR SOUTHEAST ACROSS THE
CENTRAL/SOUTHERN APPALACHIANS AND OFF THE MID-ATLANTIC COAST
WEDNESDAY. GUIDANCE DOES DEPICT A RAPIDLY SHEARING/WEAKENING
MID-LEVEL VORT MOVING ACROSS THE AREA DURING THE MORNING HOURS...
THOUGH OVERALL RISING HEIGHTS/DEVELOPING UPPER RIDGING IS INDICATED
WITH LOW LEVEL COLD ADVECTION AND DECREASING CYCLONIC CURVATURE.
THIS PRODUCES SUBSIDENCE AND DRYING ABOVE THE BOUNDARY LAYER... WITH
LITTLE/NO SYNOPTIC SCALE FORCING FOR LINGERING PRECIP. WITHIN THE
BOUNDARY LAYER HOWEVER...NORTH-NORTHEAST FLOW DOWN LAKE MICHIGAN
PRODUCES LONG FETCH AND FAIRLY STRONG MOISTURE-CONVERGENCE ALONG THE
WEST/SOUTHWEST SHORE. THERMODYNAMIC PROFILES BASED ON 12Z WRF-NAM
AND GFS SHOW RELATIVELY MARGINAL SETUP FOR ORGANIZED SNOW SHOWERS
HOWEVER...WITH 850 MB TEMPS ONLY AROUND -8/9C WEDNESDAY AND
WEDNESDAY NIGHT. THIS YIELDS WATER SFC TO 850 MB DELTA T VALUES
AROUND 12/13...WITH COMPUTED EQUILIBRIUM LEVELS LESS THAN 5000 FT
AGL. WHILE SUFFICIENT TO PRODUCE LAKE EFFECT CLOUDS AND LIGHT SNOW
SHOWERS...THESE PARAMETERS SUGGEST IT WOULD BE DIFFICULT TO GET ANY
SIGNIFICANT ACCUMULATION UNLESS SNOW BAND WERE STATIONARY FOR A LONG
PERIOD OF TIME. LOW LEVEL WIND PROFILES INDICATE THAT CONVERGENCE
WILL FAVOR THE ILLINOIS SHORE INTO LAKE COUNTY INDIANA THROUGH
WEDNESDAY EVENING...THUS HAVE INDICATED SOME MINOR ACCUMULATION OF A
FEW TENTHS OF AN INCH THERE. IF STRONGER THERMODYNAMICS WERE TO
OCCUR OR THE BAND WERE TO EXPERIENCE A HIGHER RESIDENCE TIME IN ANY
ONE LOCATION PERHAPS AN INCH OR TWO COULD ACCUMULATE...THOUGH
CONFIDENCE IN THAT OCCURRING IS VERY LOW. HIGH PRESSURE RIDGE
SPREADS EAST ACROSS THE MISSISSIPPI VALLEY LATER WEDNESDAY NIGHT AND
THURSDAY...WHICH LEADS TO WINDS WEAKENING AND VEERING NORTHEAST
THURSDAY MORNING AND THEN EAST LATER IN THE DAY WITH THERMODYNAMIC
SETUP ALSO WEAKENING RAPIDLY BEYOND THURSDAY MORNING.
PERIOD OF QUIET WEATHER IS THEN ANTICIPATED AS UPPER RIDGE BUILDS
ACROSS THE CENTRAL CONUS...AND SURFACE HIGH PRESSURE RIDGE MOVES
SLOWLY ACROSS THE AREA INTO FRIDAY. TEMPERATURES MODERATE BACK
TOWARD NORMAL...THOUGH DEEP SNOW COVER FROM EARLY WEEK STORM WILL
TEMPER THINGS FOR SEVERAL DAYS. BLEND OF 925-950 TEMPS AND MOS USED
FOR TEMPS...THOUGH LEANED TOWARD COOLER ECMWF MINS WHERE SKIES
ACCOUNT SNOW COVER.
BEYOND FRIDAY...GUIDANCE IN GENERALLY GOOD AGREEMENT IN CONTINUING
TO SLOWLY MOVE UPPER RIDGE EAST ACROSS THE REGION INTO
SATURDAY...WHILE DEVELOPING UPPER LOW OVER THE SOUTHWESTERN CONUS
AND THEN SLOWLY LIFTING IT NORTHEAST ACROSS THE PLAINS. NEW 12Z
ECMWF REALLY SLOWS THINGS DOWN OVER PREVIOUS RUNS...AND ENDS UP
CUTTING OFF THE LOW OVER THE HIGH PLAINS INTO EARLY NEXT WEEK WHILE
ITS PREVIOUS RUN AND OTHER GLOBAL GUIDANCE LIFT IT NORTHEAST ACROSS
THE REGION MONDAY. WHILE SLOWER MAY VERY WELL END UP BETTER...HAVE
BASED EXTENDED PART OF FORECAST ON BETTER CONSENSUS AND AWAY FROM
12Z ECMWF. OVERALL THIS SUGGEST PRECIP THREAT EVENTUALLY INCREASES
SATURDAY NIGHT/SUNDAY AND MONDAY AS OCCLUDING LOW MOVES THROUGH THE
AREA. THICKNESS FIELDS/SOUNDINGS SUGGEST THIS SHOULD MAINLY BE A
RAIN EVENT FOR OUR AREA...WITH TEMPS INTO THE 40S/LOWER 50S BY
SUNDAY/MONDAY. WILL HAVE TO MONITOR HYDRO ISSUES AS THIS STORM
APPROACHES...AS WE WILL BE MELTING OFF THE DEEP EARLY WEEK SNOW PACK
AND THEN POTENTIALLY RAINING 0.5-1.00 INCHES OF RAIN BY THE
SUNDAY/MONDAY TIMEFRAME.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* TIMING CIGS DROPPING TO MVFR OVERNIGHT/EARLY TUESDAY MORNING.
* TIMING LIGHT SNOW STARTING OVERNIGHT.
* HEAVY SNOW DURING THE AFTERNOON/EVENING HOURS.
* GUSTY NORTHEAST/NORTH WINDS CAUSING BLOWING SNOW.
BMD
//DISCUSSION...UPDATED 06Z...
OVERNIGHT...BROAD SCALE WEAK BUT PERSISTENT ASCENT WILL GRADUALLY
SATURATE THE ATMOSPHERE TOP DOWN WITH CIGS FALLING TO MVFR AND LIGHT
SNOW LIKELY STARTING AROUND THE SAME TIME. THIS DOWNWARD TREND HAS
BEEN OCCURRING SLOWER THAN ORIGINALLY THOUGHT...SO ADJUSTED TIMING
ACCORDINGLY...WITH THE EXPECTATION FOR MVFR CIGS/LIGHT SNOW TO BEGIN
AROUND OR SHORTLY BEFORE DAYBREAK TUESDAY.
MODELS CONTINUE TO BE IN GOOD AGREEMENT REGARDING THE POTENTIAL FOR
HEAVY SNOW...POINTING AT THE AFTERNOON TO EARLY EVENING HOURS HAVING
THE WORST CONDITIONS. DONT HAVE THE BEST CONFIDENCE REGARDING 1/4SM
PREVAILING FOR SUCH A LONG PERIOD...ESPECIALLY SINCE ITS BELOW
MET/MAV LOWEST GUIDANCE...BUT THINK THAT KEEPING TEMPO 1/4SM IS
STILL A GOOD CALL AS PERIODS OF HEAVY SNOW ARE LIKELY. STRONG
FORCING EARLY IN THE AFTERNOON IS CENTERED WELL WITHIN THE DENDRITIC
GROWTH ZONE LEADING TO EFFICIENT SNOW PRODUCTION AND SNOWFALL RATES
IN EXCESS OF AN INCH PER HOUR AT TIMES. LATER IN THE EVENING...THE
DGZ DEEPENS...AND DESPITE THE FORCING BECOMING SOMEWHAT
OFFSET...FEEL THE POTENTIAL FOR LESS THAN 1SM VSBY HEAVY SNOW
CONTINUES. IN ADDITION...VERY SHALLOW INSTABILITY DEVELOPS OVER LAKE
MICHIGAN LATE IN THE AFTERNOON AND EARLY EVENING WHICH MAY HELP TO
ENHANCE SNOWFALL IN THE CHICAGO AREA. NORTHEAST WINDS WILL BEGIN TO
INCREASE EVENING AS THE GRADIENT TIGHTENS AS STRONG PRESSURE RISES
TRANSLATE EAST ACROSS THE AREA. THIS WILL LEAD TO BLOWING SNOW AND
MAY FURTHER COMPLICATE VSBY FCST. CURRENT FORECAST IS FOR 7 TO 10
INCHES OF SNOW.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN CIG TRENDS OVERNIGHT INTO EARLY TUESDAY.
* LOW TO MEDIUM CONFIDENCE LIGHT SNOW START TIME EARLY TUESDAY.
* HIGH CONFIDENCE IN HEAVY SNOW WITH PERIODS OF LESS THAN 1SM
VSBY...MEDIUM CONFIDENCE IN 1/4SM AT TIMES DURING THE
AFTERNOON...THOUGH LOW CONFIDENCE ON SPECIFIC TIMING/DURATION.
* MEDIUM TO HIGH CONFIDENCE IN WIND FORECAST.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z TUESDAY...UPDATED 00Z...
WEDNESDAY...MVFR.
THURSDAY AND FRIDAY...VFR.
SATURDAY...SLIGHT CHANCE RAIN.
SUNDAY...SLIGHT CHANCE RAIN WITH HIGHER CHANCE SUNDAY NIGHT. MVFR
POSSIBLE SUNDAY NIGHT.
MDB
&&
.MARINE...
232 PM...LOW PRESSURE OVER THE SOUTHERN PLAINS WILL MOVE NORTHEAST
TO THE OHIO VALLEY TUESDAY MORNING AS IT ABSORBS A WEAKER AREA OF
LOW PRESSURE MOVING SOUTHEAST FROM THE DAKOTAS. THIS LOW WILL THEN
QUICKLY DEEPEN JUST OFF THE MID ATLANTIC COAST WEDNESDAY. AS THE
LOW APPROACHES...THE GRADIENT WILL TIGHTEN BETWEEN A LARGE RIDGE
OF HIGH PRESSURE OVER THE PLAINS AND SOUTHERN CANADA. NORTHERLY
WINDS WILL INCREASE TO 30 KTS BY TUESDAY AFTERNOON AND CONTINUE
INTO TUESDAY NIGHT. WINDS WILL SLOWLY DIMINISH WEDNESDAY NIGHT AS
THE RIDGE SPREADS ACROSS THE REGION THURSDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-
ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...3 AM TUESDAY TO
MIDNIGHT WEDNESDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019
UNTIL MIDNIGHT WEDNESDAY.
IN...WINTER STORM WARNING...INZ001-INZ002-INZ010-INZ011-INZ019...3 AM
TUESDAY TO MIDNIGHT WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...3 AM TUESDAY TO 3 AM THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
320 PM EST TUE MAR 5 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 405 AM EST TUE MAR 5 2013
LOW PRESSURE OVER NORTHERN ARKANSAS WILL TRACK NORTHEAST ACROSS THE
OHIO VALLEY LATER TODAY AS A STRONG UPPER LOW OVER THE NORTHERN
PLAINS MOVES TO KENTUCKY TONIGHT. THESE SYSTEMS WILL MERGE
RESULTING IN WINTER STORM CONDITIONS ACROSS PARTS OF OUR NORTH AND
EAST LATER TODAY AND TONIGHT AS COLDER AIR SPREADS INTO OUR REGION.
THIS SYSTEM WILL MOVE ON TO THE EAST WEDNESDAY AND HIGH PRESSURE
OVER THE CENTRAL U.S. WILL BUILD ACROSS OUR REGION THURSDAY AND
FRIDAY. TEMPERATURES WILL BECOME BY THE WEEKEND AS THE STRONG UPPER
LOW MOVES OFF THE EASTERN U.S. AND AN UPPER RIDGE OF HIGH PRESSURE
BUILDS OUR WAY.
THIS SYSTEM WILL CONTINUE ON TO THE EAST AND AND LOW PRESSURE
TRACKING FROM THE PLAINS INTO THE GREAT LAKES WILL BRING A CHANCE OF
RAIN EARLY NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1155 AM EST TUE MAR 5 2013
MUCH OF THE FORECAST AREA IN A RELATIVE LULL WITH LIGHT PRECIP AT
THE MOMENT THIS MORNING. LIGHT RAIN OCCASIONALLY MIXING WITH WET
SNOWFLAKES AND EVEN A FEW ICE PELLETS IMPACTING FAR NORTHERN
PORTIONS OF THE FORECAST AREA AT 16Z...WITH PRECIP EXPANDING INTO
THE REGION FROM THE SOUTHWEST WITH LOW PRESSURE APPROACHING. TEMPS
WERE GENERALLY IN THE 30S LATE THIS MORNING.
LOT TO TALK ABOUT FOR THE UPDATE WITH SOME CHANGES IN ORDER TO THE
HEADLINES AND SNOWFALL TOTALS BASED ON MOST RECENT MODEL DATA.
SOUNDINGS THIS MORNING SHOWING SLOW MOISTENING OF THE LOWER LEVELS
AND WILL SEE PRECIP COVERAGE EXPAND THIS AFTERNOON AS ISENTROPIC
LIFT AND FORCING ALOFT INCREASE WITH THE PASSAGE OF LOW PRESSURE
ALONG THE OHIO RIVER. MEANWHILE...INTENSE UPPER LOW CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WILL APPROACH AND ROTATE INTO THE
OHIO VALLEY BY THIS EVENING. MODEL SOUNDING AND 850MB TEMP
ANALYSIS SHOW COLDER AIR THROUGH THE BOUNDARY LAYER EXPANDING INTO
THE FORECAST AREA FROM THE NORTHWEST THROUGH THE AFTERNOON...WITH
PRECIP CHANGING OVER TO SNOW ACROSS THE ENTIRE FORECAST AREA BY 00Z.
ONCE THE CHANGEOVER TO SNOW TAKES PLACE...EXPECT A NUMBER OF
PARAMETERS TO COME INTO PLAY TO PROVIDE A PERIOD OF MODERATE TO
POTENTIALLY HEAVY SNOWFALL THIS EVENING FOCUSED ACROSS THE
NORTHEAST HALF OF THE FORECAST AREA...GENERALLY ALONG AND N/E OF THE
INTERSTATE 74 CORRIDOR. AS THE UPPER LOW ROTATES THROUGH THE OHIO
VALLEY THIS EVENING...AXIS OF MID LEVEL DEFORMATION COMBINED WITH
FRONTOGENETIC FORCING WILL COMBINE WITH STRONG ISENTROPIC LIFT...
HIGH DIV Q VALUES AND THE PASSAGE OF A DECENT DENDRITIC GROWTH
ZONE TO PROVIDE AMPLE FORCING FOR HEAVY SNOW. THESE FEATURES MAY
ALSO COMBINE TO ALLOW FOR HIGHER SNOW RATIOS UNDERNEATH THE DEEPER
FORCING WHICH WOULD SERVE TO ACCENTUATE SNOWFALL RATES. BY 06Z AS
THE SECONDARY COASTAL LOW BEGINS TO GET ITS ACT TOGETHER...MODEL
GUIDANCE SHOWING POTENTIAL FOR A STRONG LOW LEVEL JET TO PULL
ATLANTIC MOISTURE BACK WEST INTO THE REGION AND INTERACT WITH AN
IMPRESSIVE TROWAL TO MAINTAIN STRONG LIFT AND MODERATE TO HEAVY
SNOWFALL EVEN AS BETTER DEFORMATION AND MID LEVEL FORCING BEGINS
TO DIMINISH WITH THE UPPER LOW MOVING INTO THE CENTRAL
APPALACHIANS. THE TROWAL WILL THEN ROTATE SOUTHEAST THROUGH THE
FORECAST AREA BETWEEN 06-12Z ON THE BACK SIDE OF THE UPPER LOW.
THESE FEATURES ABOVE WITH THE MOISTURE PRESENT SUPPORT SNOWFALL
TOTALS BY WEDNESDAY MORNING NORTHEAST OF INTERSTATE 74 OF 4 TO 5
INCHES TO POSSIBLY AS MUCH AS 8 INCHES OVER NORTHEAST COUNTIES.
MAJORITY OF THE 12Z GUIDANCE SUPPORTS THIS THINKING...WITH THE NAM
AND RAP SUGGESTING POTENTIAL FOR EVEN HIGHER AMOUNTS TO THE
NORTHEAST OF INDY METRO. REGARDLESS CONSIDERING ABOVE
THOUGHTS...FEEL COMFORTABLE IN EXPANDING THE WARNING WEST A ROW OF
COUNTIES TO INCLUDE MARION COUNTY AND MUCH OF THE INDY METRO.
HEAVIEST SNOWFALL LIKELY TO COME THIS EVENING IN THE WARNING AREA
THROUGH ABOUT 06-08Z WITH GRADUALLY LIGHTENING RATES THEREAFTER AS
THE TROWAL ROTATES SOUTHEAST. FOR SIMPLICITY SAKE...HAVE ADJUSTED
ALL HEADLINES TO BEGIN AT 20Z.
WILL REVISIT DECISIONS FURTHER FOR MAIN FORECAST PACKAGE THIS
AFTERNOON AS MORE SHORT RANGE MODEL GUIDANCE BECOMES AVAILABLE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 405 AM EST TUE MAR 5 2013
ON WEDNESDAY...BROAD LOWER LEVEL CYCLONIC FLOW LOOKS TO PERSIST IN
THE WAKE OF THE DEPARTED LOW. A WEAK RIDGE OF HIGH PRESSURE
APPEARS SET UP OVER THE CENTRAL PLAINS AND MISSISSIPPI RIVER
VALLEY. THIS ALL TOO FAMILIAR PATTERN WAS MUCH OF WHAT WE
EXPERIENCED LAST WEEK...RESULTING IN CLOUDS...AND OCCASIONAL SNOW
SHOWERS OR FLURRIES. THUS WITH THE COLD CYCLONIC FLOW AND FORECAST
SOUNDINGS INDICATING GOOD MOISTURE WILL KEEP FLURRIES IN THE
FORECAST FOR NOW AND TREND HIGH TEMPS COOLER THAN MAVMOS.
NAM AND GFS INDICATE THE WEAK RIDGE WILL BUILD ACROSS THE AREA ON
WEDNESDAY NIGHT AND THURSDAY AND LOWER LEVEL FLOW BECOMES MORE
ANTI CYCLONIC THUS WILL TREND TOWARD PARTLY CLOUDY DURING THIS
TIME WITH TEMPERATURES BELOW GUIDANCE AS MINIMAL WARM AIR ADVECTION
LOOKS TO TAKE PLACE AND A SNOW PACK IS EXPECTED TO BE ON THE GROUND.
FURTHERMORE FORECAST SOUNDINGS STILL HINT AT LOWER LEVEL SATURATION
POSSIBLE WITH EASILY ATTAINABLE CONVECTIVE TEMPERATURES IN THE LOWER
30S.
HIGH PRESSURE WILL BUILD ACROSS OUR REGION THURSDAY AND FRIDAY. WITH
CLEARING SKIES AND SOME SNOW COVER WILL LOWER TEMPERATURES A LITTLE
FROM PREVIOUS FORECAST.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 241 AM EST TUE MAR 5 2013
LONG TERM PERIOD LOOKS TO BE A TALE OF TWO HALVES...WITH A FAIRLY
STRONG SURFACE AND UPPER RIDGE PROVIDING A QUIET END TO THE
WEEK...FOLLOWED A LARGE UPPER LEVEL SYSTEM WHICH WILL MOVE OUT OF
THE WEST AND BRING RAIN CHANCES FROM THE LATTER PART OF THE
WEEKEND INTO EARLY NEXT WEEK. GFS IS MUCH FASTER WITH THIS SYSTEM
WHICH LOOKS A LITTLE SUSPICIOUS GIVEN THE AFOREMENTIONED UPPER
RIDGE AND THE PRESENCE OF A CLOSED LOW. HAVE LEANED TOWARD EURO
AND DELAYED POPS FROM ALLBLEND INITIALIZATION.
OTHERWISE ALLBLEND INITIALIZED WELL. TEMPS SHOULD BE BACK TO NEAR
OR ABOVE CLIMATOLOGY FOR THE FIRST TIME IN A WHILE...AND
FORTUNATELY PRECIPITATION TYPE ISSUES LOOK TO BE NONEXISTENT FOR NOW.
&&
.AVIATION /DISCUSSION FOR THE 052100 KIND TAF UPDATE/...
ISSUED AT 320 PM EST TUE MAR 5 2013
STILL APPEARS RAIN WILL CHANGE OVER TO SNOW AT KIND OVER THE NEXT
COUPLE OF HOURS BASED ON UPSTREAM OBSERVATIONS...ALONG WITH A WIND
SHIFT TO 280-310 DEGREES AS A SURFACE TROUGH PASSES THROUGH.
WIDESPREAD IFR/LIFR SHOULD CONTINUE INTO THE EVENING HOURS. WILL
DROP THE WIND SPEEDS A LITTLE ON THE UPDATE WITH KIND NEAR THE
SURFACE TROUGH...OTHERWISE NO SIGNIFICANT CHANGES MADE AT THIS TIME.
PREVIOUS DISCUSSION FOLLOWS.
FLYING CONDITIONS ARE ALREADY BECOMING POOR EARLY THIS AFTERNOON AS
A WINTER STORM MOVES INTO THE OHIO VALLEY. PRECIP ACROSS THE AREA
ONLY IN THE FORM OF RAIN OR DRIZZLE AT THIS TIME. STILL EXPECTED
OVER THE NEXT FEW HOURS A TRANSITION TO -RASN...AND THEN EVENTUALLY
ALL SNOW BY THIS LATE AFTERNOON AND EVENING...WITH WIDESPREAD IFR
CONDITIONS OR WORSE EXPECTED. (MANY TERMINALS SUCH AS KIND HAVE
ALREADY DROPPED TO IFR AND THIS HAS BEEN DEPICTED IN THE LATEST SET
OF TAFS.
WINDS WILL STRENGTHEN TODAY AS THE PRESSURE GRADIENT TIGHTENS...AND
GUSTS APPROACHING 30KT OVERNIGHT TONIGHT ON THE BACK SIDE OF THE LOW
CAN BE EXPECTED IN MANY LOCATIONS.
AFTER THE SURFACE LOWS SLIDES TO THE EAST OF THE REGION BY WED
MORNING...PRECIPITATION WILL TAPER OFF SIGNIFICANTLY...HOWEVER AS IS
THE CASE WITH THESE SYSTEMS DURING THIS TIME OF YEAR...EXPECT FROM
LINGERING LIGHT SNOW AND/OR FLURRIES IN ADDITION TO THE STRATUS. SO
MFVR CONDITIONS WILL ROUND OUT THE END OF THE TAF PERIOD AND
POTENTIALLY CONTINUE BEYOND INTO WED NIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR INZ021-028>031-037>042-047>049-056-057-065.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR INZ035-036-043>046-051>055-060>064-069>072.
&&
$$
SYNOPSIS...JH
NEAR TERM...RYAN
SHORT TERM...JH
LONG TERM....NIELD
AVIATION...SMF/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1156 AM EST TUE MAR 5 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 405 AM EST TUE MAR 5 2013
LOW PRESSURE OVER NORTHERN ARKANSAS WILL TRACK NORTHEAST ACROSS THE
OHIO VALLEY LATER TODAY AS A STRONG UPPER LOW OVER THE NORTHERN
PLAINS MOVES TO KENTUCKY TONIGHT. THESE SYSTEMS WILL MERGE
RESULTING IN WINTER STORM CONDITIONS ACROSS PARTS OF OUR NORTH AND
EAST LATER TODAY AND TONIGHT AS COLDER AIR SPREADS INTO OUR REGION.
THIS SYSTEM WILL MOVE ON TO THE EAST WEDNESDAY AND HIGH PRESSURE
OVER THE CENTRAL U.S. WILL BUILD ACROSS OUR REGION THURSDAY AND
FRIDAY. TEMPERATURES WILL BECOME BY THE WEEKEND AS THE STRONG UPPER
LOW MOVES OFF THE EASTERN U.S. AND AN UPPER RIDGE OF HIGH PRESSURE
BUILDS OUR WAY.
THIS SYSTEM WILL CONTINUE ON TO THE EAST AND AND LOW PRESSURE
TRACKING FROM THE PLAINS INTO THE GREAT LAKES WILL BRING A CHANCE OF
RAIN EARLY NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1155 AM EST TUE MAR 5 2013
MUCH OF THE FORECAST AREA IN A RELATIVE LULL WITH LIGHT PRECIP AT
THE MOMENT THIS MORNING. LIGHT RAIN OCCASIONALLY MIXING WITH WET
SNOWFLAKES AND EVEN A FEW ICE PELLETS IMPACTING FAR NORTHERN
PORTIONS OF THE FORECAST AREA AT 16Z...WITH PRECIP EXPANDING INTO
THE REGION FROM THE SOUTHWEST WITH LOW PRESSURE APPROACHING. TEMPS
WERE GENERALLY IN THE 30S LATE THIS MORNING.
LOT TO TALK ABOUT FOR THE UPDATE WITH SOME CHANGES IN ORDER TO THE
HEADLINES AND SNOWFALL TOTALS BASED ON MOST RECENT MODEL DATA.
SOUNDINGS THIS MORNING SHOWING SLOW MOISTENING OF THE LOWER LEVELS
AND WILL SEE PRECIP COVERAGE EXPAND THIS AFTERNOON AS ISENTROPIC
LIFT AND FORCING ALOFT INCREASE WITH THE PASSAGE OF LOW PRESSURE
ALONG THE OHIO RIVER. MEANWHILE...INTENSE UPPER LOW CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WILL APPROACH AND ROTATE INTO THE
OHIO VALLEY BY THIS EVENING. MODEL SOUNDING AND 850MB TEMP
ANALYSIS SHOW COLDER AIR THROUGH THE BOUNDARY LAYER EXPANDING INTO
THE FORECAST AREA FROM THE NORTHWEST THROUGH THE AFTERNOON...WITH
PRECIP CHANGING OVER TO SNOW ACROSS THE ENTIRE FORECAST AREA BY 00Z.
ONCE THE CHANGEOVER TO SNOW TAKES PLACE...EXPECT A NUMBER OF
PARAMETERS TO COME INTO PLAY TO PROVIDE A PERIOD OF MODERATE TO
POTENTIALLY HEAVY SNOWFALL THIS EVENING FOCUSED ACROSS THE
NORTHEAST HALF OF THE FORECAST AREA...GENERALLY ALONG AND N/E OF THE
INTERSTATE 74 CORRIDOR. AS THE UPPER LOW ROTATES THROUGH THE OHIO
VALLEY THIS EVENING...AXIS OF MID LEVEL DEFORMATION COMBINED WITH
FRONTOGENETIC FORCING WILL COMBINE WITH STRONG ISENTROPIC LIFT...
HIGH DIV Q VALUES AND THE PASSAGE OF A DECENT DENDRITIC GROWTH
ZONE TO PROVIDE AMPLE FORCING FOR HEAVY SNOW. THESE FEATURES MAY
ALSO COMBINE TO ALLOW FOR HIGHER SNOW RATIOS UNDERNEATH THE DEEPER
FORCING WHICH WOULD SERVE TO ACCENTUATE SNOWFALL RATES. BY 06Z AS
THE SECONDARY COASTAL LOW BEGINS TO GET ITS ACT TOGETHER...MODEL
GUIDANCE SHOWING POTENTIAL FOR A STRONG LOW LEVEL JET TO PULL
ATLANTIC MOISTURE BACK WEST INTO THE REGION AND INTERACT WITH AN
IMPRESSIVE TROWAL TO MAINTAIN STRONG LIFT AND MODERATE TO HEAVY
SNOWFALL EVEN AS BETTER DEFORMATION AND MID LEVEL FORCING BEGINS
TO DIMINISH WITH THE UPPER LOW MOVING INTO THE CENTRAL
APPALACHIANS. THE TROWAL WILL THEN ROTATE SOUTHEAST THROUGH THE
FORECAST AREA BETWEEN 06-12Z ON THE BACK SIDE OF THE UPPER LOW.
THESE FEATURES ABOVE WITH THE MOISTURE PRESENT SUPPORT SNOWFALL
TOTALS BY WEDNESDAY MORNING NORTHEAST OF INTERSTATE 74 OF 4 TO 5
INCHES TO POSSIBLY AS MUCH AS 8 INCHES OVER NORTHEAST COUNTIES.
MAJORITY OF THE 12Z GUIDANCE SUPPORTS THIS THINKING...WITH THE NAM
AND RAP SUGGESTING POTENTIAL FOR EVEN HIGHER AMOUNTS TO THE
NORTHEAST OF INDY METRO. REGARDLESS CONSIDERING ABOVE
THOUGHTS...FEEL COMFORTABLE IN EXPANDING THE WARNING WEST A ROW OF
COUNTIES TO INCLUDE MARION COUNTY AND MUCH OF THE INDY METRO.
HEAVIEST SNOWFALL LIKELY TO COME THIS EVENING IN THE WARNING AREA
THROUGH ABOUT 06-08Z WITH GRADUALLY LIGHTENING RATES THEREAFTER AS
THE TROWAL ROTATES SOUTHEAST. FOR SIMPLICITY SAKE...HAVE ADJUSTED
ALL HEADLINES TO BEGIN AT 20Z.
WILL REVISIT DECISIONS FURTHER FOR MAIN FORECAST PACKAGE THIS
AFTERNOON AS MORE SHORT RANGE MODEL GUIDANCE BECOMES AVAILABLE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 405 AM EST TUE MAR 5 2013
ON WEDNESDAY...BROAD LOWER LEVEL CYCLONIC FLOW LOOKS TO PERSIST IN
THE WAKE OF THE DEPARTED LOW. A WEAK RIDGE OF HIGH PRESSURE
APPEARS SET UP OVER THE CENTRAL PLAINS AND MISSISSIPPI RIVER
VALLEY. THIS ALL TOO FAMILIAR PATTERN WAS MUCH OF WHAT WE
EXPERIENCED LAST WEEK...RESULTING IN CLOUDS...AND OCCASIONAL SNOW
SHOWERS OR FLURRIES. THUS WITH THE COLD CYCLONIC FLOW AND FORECAST
SOUNDINGS INDICATING GOOD MOISTURE WILL KEEP FLURRIES IN THE
FORECAST FOR NOW AND TREND HIGH TEMPS COOLER THAN MAVMOS.
NAM AND GFS INDICATE THE WEAK RIDGE WILL BUILD ACROSS THE AREA ON
WEDNESDAY NIGHT AND THURSDAY AND LOWER LEVEL FLOW BECOMES MORE
ANTI CYCLONIC THUS WILL TREND TOWARD PARTLY CLOUDY DURING THIS
TIME WITH TEMPERATURES BELOW GUIDANCE AS MINIMAL WARM AIR ADVECTION
LOOKS TO TAKE PLACE AND A SNOW PACK IS EXPECTED TO BE ON THE GROUND.
FURTHERMORE FORECAST SOUNDINGS STILL HINT AT LOWER LEVEL SATURATION
POSSIBLE WITH EASILY ATTAINABLE CONVECTIVE TEMPERATURES IN THE LOWER
30S.
HIGH PRESSURE WILL BUILD ACROSS OUR REGION THURSDAY AND FRIDAY. WITH
CLEARING SKIES AND SOME SNOW COVER WILL LOWER TEMPERATURES A LITTLE
FROM PREVIOUS FORECAST.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 241 AM EST TUE MAR 5 2013
LONG TERM PERIOD LOOKS TO BE A TALE OF TWO HALVES...WITH A FAIRLY
STRONG SURFACE AND UPPER RIDGE PROVIDING A QUIET END TO THE
WEEK...FOLLOWED A LARGE UPPER LEVEL SYSTEM WHICH WILL MOVE OUT OF
THE WEST AND BRING RAIN CHANCES FROM THE LATTER PART OF THE
WEEKEND INTO EARLY NEXT WEEK. GFS IS MUCH FASTER WITH THIS SYSTEM
WHICH LOOKS A LITTLE SUSPICIOUS GIVEN THE AFOREMENTIONED UPPER
RIDGE AND THE PRESENCE OF A CLOSED LOW. HAVE LEANED TOWARD EURO
AND DELAYED POPS FROM ALLBLEND INITIALIZATION.
OTHERWISE ALLBLEND INITIALIZED WELL. TEMPS SHOULD BE BACK TO NEAR
OR ABOVE CLIMATOLOGY FOR THE FIRST TIME IN A WHILE...AND
FORTUNATELY PRECIPITATION TYPE ISSUES LOOK TO BE NONEXISTENT FOR NOW.
&&
.AVIATION /DISCUSSION FOR THE 051800Z TAFS/...
ISSUED AT 1155 AM EST TUE MAR 5 2013
FLYING CONDITIONS ARE ALREADY BECOMING POOR EARLY THIS AFTERNOON AS
A WINTER STORM MOVES INTO THE OHIO VALLEY. PRECIP ACROSS THE AREA
ONLY IN THE FORM OF RAIN OR DRIZZLE AT THIS TIME. STILL EXPECTED
OVER THE NEXT FEW HOURS A TRANSITION TO -RASN...AND THEN EVENTUALLY
ALL SNOW BY THIS LATE AFTERNOON AND EVENING...WITH WIDESPREAD IFR
CONDITIONS OR WORSE EXPECTED. (MANY TERMINALS SUCH AS KIND HAVE
ALREADY DROPPED TO IFR AND THIS HAS BEEN DEPICTED IN THE LATEST SET
OF TAFS.
WINDS WILL STRENGTHEN TODAY AS THE PRESSURE GRADIENT TIGHTENS...AND
GUSTS APPROACHING 30KT OVERNIGHT TONIGHT ON THE BACK SIDE OF THE LOW
CAN BE EXPECTED IN MANY LOCATIONS.
AFTER THE SURFACE LOWS SLIDES TO THE EAST OF THE REGION BY WED
MORNING...PRECIPITATION WILL TAPER OFF SIGNIFICANTLY...HOWEVER AS IS
THE CASE WITH THESE SYSTEMS DURING THIS TIME OF YEAR...EXPECT FROM
LINGERING LIGHT SNOW AND/OR FLURRIES IN ADDITION TO THE STRATUS. SO
MFVR CONDITIONS WILL ROUND OUT THE END OF THE TAF PERIOD AND
POTENTIALLY CONTINUE BEYOND INTO WED NIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR INZ021-028>031-037>042-047>049-056-057-065.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR INZ035-036-043>046-051>055-060>064-069>072.
&&
$$
SYNOPSIS...JH
NEAR TERM...RYAN
SHORT TERM...JH
LONG TERM....NIELD
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1155 AM EST TUE MAR 5 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 405 AM EST TUE MAR 5 2013
LOW PRESSURE OVER NORTHERN ARKANSAS WILL TRACK NORTHEAST ACROSS THE
OHIO VALLEY LATER TODAY AS A STRONG UPPER LOW OVER THE NORTHERN
PLAINS MOVES TO KENTUCKY TONIGHT. THESE SYSTEMS WILL MERGE
RESULTING IN WINTER STORM CONDITIONS ACROSS PARTS OF OUR NORTH AND
EAST LATER TODAY AND TONIGHT AS COLDER AIR SPREADS INTO OUR REGION.
THIS SYSTEM WILL MOVE ON TO THE EAST WEDNESDAY AND HIGH PRESSURE
OVER THE CENTRAL U.S. WILL BUILD ACROSS OUR REGION THURSDAY AND
FRIDAY. TEMPERATURES WILL BECOME BY THE WEEKEND AS THE STRONG UPPER
LOW MOVES OFF THE EASTERN U.S. AND AN UPPER RIDGE OF HIGH PRESSURE
BUILDS OUR WAY.
THIS SYSTEM WILL CONTINUE ON TO THE EAST AND AND LOW PRESSURE
TRACKING FROM THE PLAINS INTO THE GREAT LAKES WILL BRING A CHANCE OF
RAIN EARLY NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1155 AM EST TUE MAR 5 2013
MUCH OF THE FORECAST AREA IN A RELATIVE LULL WITH LIGHT PRECIP AT
THE MOMENT THIS MORNING. LIGHT RAIN OCCASIONALLY MIXING WITH WET
SNOWFLAKES AND EVEN A FEW ICE PELLETS IMPACTING FAR NORTHERN
PORTIONS OF THE FORECAST AREA AT 16Z...WITH PRECIP EXPANDING INTO
THE REGION FROM THE SOUTHWEST WITH LOW PRESSURE APPROACHING. TEMPS
WERE GENERALLY IN THE 30S LATE THIS MORNING.
LOT TO TALK ABOUT FOR THE UPDATE WITH SOME CHANGES IN ORDER TO THE
HEADLINES AND SNOWFALL TOTALS BASED ON MOST RECENT MODEL DATA.
SOUNDINGS THIS MORNING SHOWING SLOW MOISTENING OF THE LOWER LEVELS
AND WILL SEE PRECIP COVERAGE EXPAND THIS AFTERNOON AS ISENTROPIC
LIFT AND FORCING ALOFT INCREASE WITH THE PASSAGE OF LOW PRESSURE
ALONG THE OHIO RIVER. MEANWHILE...INTENSE UPPER LOW CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WILL APPROACH AND ROTATE INTO THE
OHIO VALLEY BY THIS EVENING. MODEL SOUNDING AND 850MB TEMP
ANALYSIS SHOW COLDER AIR THROUGH THE BOUNDARY LAYER EXPANDING INTO
THE FORECAST AREA FROM THE NORTHWEST THROUGH THE AFTERNOON...WITH
PRECIP CHANGING OVER TO SNOW ACROSS THE ENTIRE FORECAST AREA BY 00Z.
ONCE THE CHANGEOVER TO SNOW TAKES PLACE...EXPECT A NUMBER OF
PARAMETERS TO COME INTO PLAY TO PROVIDE A PERIOD OF MODERATE TO
POTENTIALLY HEAVY SNOWFALL THIS EVENING FOCUSED ACROSS THE
NORTHEAST HALF OF THE FORECAST AREA...GENERALLY ALONG AND N/E OF THE
INTERSTATE 74 CORRIDOR. AS THE UPPER LOW ROTATES THROUGH THE OHIO
VALLEY THIS EVENING...AXIS OF MID LEVEL DEFORMATION COMBINED WITH
FRONTOGENETIC FORCING WILL COMBINE WITH STRONG ISENTROPIC LIFT...
HIGH DIV Q VALUES AND THE PASSAGE OF A DECENT DENDRITIC GROWTH
ZONE TO PROVIDE AMPLE FORCING FOR HEAVY SNOW. THESE FEATURES MAY
ALSO COMBINE TO ALLOW FOR HIGHER SNOW RATIOS UNDERNEATH THE DEEPER
FORCING WHICH WOULD SERVE TO ACCENTUATE SNOWFALL RATES. BY 06Z AS
THE SECONDARY COASTAL LOW BEGINS TO GET ITS ACT TOGETHER...MODEL
GUIDANCE SHOWING POTENTIAL FOR A STRONG LOW LEVEL JET TO PULL
ATLANTIC MOISTURE BACK WEST INTO THE REGION AND INTERACT WITH AN
IMPRESSIVE TROWAL TO MAINTAIN STRONG LIFT AND MODERATE TO HEAVY
SNOWFALL EVEN AS BETTER DEFORMATION AND MID LEVEL FORCING BEGINS
TO DIMINISH WITH THE UPPER LOW MOVING INTO THE CENTRAL
APPALACHIANS. THE TROWAL WILL THEN ROTATE SOUTHEAST THROUGH THE
FORECAST AREA BETWEEN 06-12Z ON THE BACK SIDE OF THE UPPER LOW.
THESE FEATURES ABOVE WITH THE MOISTURE PRESENT SUPPORT SNOWFALL
TOTALS BY WEDNESDAY MORNING NORTHEAST OF INTERSTATE 74 OF 4 TO 5
INCHES TO POSSIBLY AS MUCH AS 8 INCHES OVER NORTHEAST COUNTIES.
MAJORITY OF THE 12Z GUIDANCE SUPPORTS THIS THINKING...WITH THE NAM
AND RAP SUGGESTING POTENTIAL FOR EVEN HIGHER AMOUNTS TO THE
NORTHEAST OF INDY METRO. REGARDLESS CONSIDERING ABOVE
THOUGHTS...FEEL COMFORTABLE IN EXPANDING THE WARNING WEST A ROW OF
COUNTIES TO INCLUDE MARION COUNTY AND MUCH OF THE INDY METRO.
HEAVIEST SNOWFALL LIKELY TO COME THIS EVENING IN THE WARNING AREA
THROUGH ABOUT 06-08Z WITH GRADUALLY LIGHTENING RATES THEREAFTER AS
THE TROWAL ROTATES SOUTHEAST. FOR SIMPLICITY SAKE...HAVE ADJUSTED
ALL HEADLINES TO BEGIN AT 20Z.
WILL REVISIT DECISIONS FURTHER FOR MAIN FORECAST PACKAGE THIS
AFTERNOON AS MORE SHORT RANGE MODEL GUIDANCE BECOMES AVAILABLE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 405 AM EST TUE MAR 5 2013
ON WEDNESDAY...BROAD LOWER LEVEL CYCLONIC FLOW LOOKS TO PERSIST IN
THE WAKE OF THE DEPARTED LOW. A WEAK RIDGE OF HIGH PRESSURE
APPEARS SET UP OVER THE CENTRAL PLAINS AND MISSISSIPPI RIVER
VALLEY. THIS ALL TOO FAMILIAR PATTERN WAS MUCH OF WHAT WE
EXPERIENCED LAST WEEK...RESULTING IN CLOUDS...AND OCCASIONAL SNOW
SHOWERS OR FLURRIES. THUS WITH THE COLD CYCLONIC FLOW AND FORECAST
SOUNDINGS INDICATING GOOD MOISTURE WILL KEEP FLURRIES IN THE
FORECAST FOR NOW AND TREND HIGH TEMPS COOLER THAN MAVMOS.
NAM AND GFS INDICATE THE WEAK RIDGE WILL BUILD ACROSS THE AREA ON
WEDNESDAY NIGHT AND THURSDAY AND LOWER LEVEL FLOW BECOMES MORE
ANTI CYCLONIC THUS WILL TREND TOWARD PARTLY CLOUDY DURING THIS
TIME WITH TEMPERATURES BELOW GUIDANCE AS MINIMAL WARM AIR ADVECTION
LOOKS TO TAKE PLACE AND A SNOW PACK IS EXPECTED TO BE ON THE GROUND.
FURTHERMORE FORECAST SOUNDINGS STILL HINT AT LOWER LEVEL SATURATION
POSSIBLE WITH EASILY ATTAINABLE CONVECTIVE TEMPERATURES IN THE LOWER
30S.
HIGH PRESSURE WILL BUILD ACROSS OUR REGION THURSDAY AND FRIDAY. WITH
CLEARING SKIES AND SOME SNOW COVER WILL LOWER TEMPERATURES A LITTLE
FROM PREVIOUS FORECAST.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 241 AM EST TUE MAR 5 2013
LONG TERM PERIOD LOOKS TO BE A TALE OF TWO HALVES...WITH A FAIRLY
STRONG SURFACE AND UPPER RIDGE PROVIDING A QUIET END TO THE
WEEK...FOLLOWED A LARGE UPPER LEVEL SYSTEM WHICH WILL MOVE OUT OF
THE WEST AND BRING RAIN CHANCES FROM THE LATTER PART OF THE
WEEKEND INTO EARLY NEXT WEEK. GFS IS MUCH FASTER WITH THIS SYSTEM
WHICH LOOKS A LITTLE SUSPICIOUS GIVEN THE AFOREMENTIONED UPPER
RIDGE AND THE PRESENCE OF A CLOSED LOW. HAVE LEANED TOWARD EURO
AND DELAYED POPS FROM ALLBLEND INITIALIZATION.
OTHERWISE ALLBLEND INITIALIZED WELL. TEMPS SHOULD BE BACK TO NEAR
OR ABOVE CLIMATOLOGY FOR THE FIRST TIME IN A WHILE...AND
FORTUNATELY PRECIPITATION TYPE ISSUES LOOK TO BE NONEXISTENT FOR NOW.
&&
.AVIATION /DISCUSSION FOR THE 051200Z TAFS/...
ISSUED AT 917 AM EST TUE MAR 5 2013
1430Z UPDATE...FEW COSMETIC CHANGES MADE TO THE TIMING FOR SEVERAL
OF THE TERMINALS. OTHERWISE NO OTHER CHANGES NEEDED AT THIS TIME.
PREVIOUS DISCUSSION FOLLOWS...
FLYING CONDITIONS BECOMING POOR THIS PERIOD AS A WINTER STORM MOVES
THROUGH THE REGION.
PRECIP ACROSS THE AREA SHOULD BEGIN AS ALL RAIN OR PERHAPS A VERY
BRIEF MIX AT LAF...BUT WITH MODELS TRENDING WARMER THINK THAT RAIN
IS THE PREDOMINANT TYPE THERE. PRECIP HAS BEEN SLOWER TO DEVELOP
THAN PREVIOUSLY EXPECTED AND HAVE DELAYED THIS SLIGHTLY.
BEGINNING EARLY THIS AFTERNOON AT LAF AND PUSHING SOUTH ACROSS THE
AREA...RAIN WILL GRADUALLY CHANGE TO SNOW. A COUPLE HOURS OF MIXED
RAIN AND SNOW...WITH AN OUTSIDE CHANCE AT SOME SLEET OR FREEZING
RAIN.
PRECIPITATION WILL BE ALL SNOW BY LATE AFTERNOON TO EARLY EVENING
ACROSS THE SITES...WITH WIDESPREAD IFR CONDITIONS OR WORSE EXPECTED.
WINDS WILL STRENGTHEN TODAY AS THE PRESSURE GRADIENT TIGHTENS...AND
MAY GUST APPROACHING 30KT OVERNIGHT TONIGHT ON THE BACK SIDE OF THE
LOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR INZ021-028>031-037>042-047>049-056-057-065.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR INZ035-036-043>046-051>055-060>064-069>072.
&&
$$
SYNOPSIS...JH
NEAR TERM...RYAN
SHORT TERM...JH
LONG TERM....NIELD
AVIATION...NIELD/SMF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
541 PM CST WED MAR 6 2013
.UPDATE...
SHORT TERM MODELS INCLUDING THE HRRR AND RAP13 CONTINUE TO
REPRESENT THE STRATUS FIELD BEST...AND BOTH SUGGEST IT WILL HANG
ON ALL NIGHT. AS SEEN ON SATELLITE TRENDS SINCE 430 PM...THE EDGE
OF THE STRATUS IS NO LONGER MOVING/DISSIPATING. IF IT IS...IT IS
NOW EXCRUCIATINGLY SLOW.
&&
.AVIATION...
A DIFFICULT CLEARING TREND WILL DOMINATE THE AVIATION FORECAST
TONIGHT...WITH CLEARING POSSIBLY DELAYED UNTIL TOMORROW MORNING AT
ALL SITES. THE CIGS REMAIN MVFR AROUND 1800 FT...AND THE EDGE IS
NEAR THE CID AND DBQ AIRPORTS...BUT IS FULLY ENTRENCHED AT MLI AND
BRL. LIGHT WINDS WILL LAST THROUGH THE NIGHT...WITH SOME PATCHY 3
-6 MILE FOG LATE TONIGHT ESPECIALLY AT CID AND DBQ WHERE CLEARING
IS MORE LIKELY BEFORE DAWN. ONCE SKIES CLEAR EITHER LATE TONIGHT
OR TOMORROW MORNING...A VFR/CLEAR DAY IS EXPECTED THURSDAY.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1138 PM CST MON MAR 4 2013
.AVIATION...
A SURFACE TROF DEVELOPING FROM SOUTHEAST IOWA THROUGH NORTHWEST
IOWA OVERNIGHT WILL MOVE SOUTH INTO MISSOURI BY LATE TUESDAY
AFTERNOON. SNOW WILL CONTINUE TO SPREAD OVER THE AREA LATE TONIGHT
AND TAPER OFF TUESDAY AFTERNOON AS THE TROF MOVES SOUTH. NORTH
TO NORTHWEST WINDS WILL INCREASE LATE TUESDAY MORNING AND INTO THE
AFTERNOON WITH GUSTS AROUND 25KTS ESPECIALLY WEST OF THE
MISSISSIPPI RIVER.
CONDITIONS WILL DETERIORATE EARLY THIS MORNING WITH WIDESPREAD
MVFR CIGS IN THE 1KFT TO 2KFT DEVELOPING BY 3 AM THEN LOWERING
BELOW 1KFT BY 6 AM. THE DEVELOPING SNOW WILL DROP VSBYS DOWN TO
AROUND A MILE BETWEEN 3 AM AND 6 AM WITH VISIBILITIES FREQUENTLY
DOWN TO A HALF MILE OR LESS FROM 6AM THROUGH NOON. THE SNOW SHOULD
TAPER OFF DURING THE AFTERNOON BUT INCREASING NORTH AND NORTHWEST
WINDS WILL CAUSE BLOWING SNOW WHICH COULD AID IN KEEPING
VISIBILITIES UNDER 3 MILES THROUGH THE AFTERNOON. BY LATE
AFTERNOON OR EARLY EVENING THE BLOWING SNOW WILL END AS THE WINDS
DIMINISH. CIGS SHOULD REMAIN AROUND 1KFT THROUGH MIDNIGHT.
DLF
&&
.PREV DISCUSSION... /ISSUED 922 PM CST MON MAR 4 2013/
UPDATE...
JUST SENT AN UPDATE TO LOWER POPS WEST BY A CATEGORY FOR THE REST
OF THE THIS EVENING. THE PRECIP HAS BEEN SLOWER TO EVOLVE THAN
PREVIOUSLY EXPECTED AND IT NOW LOOKS LIKE ANY SIGNIFICANT
PRECIP/SNOW SHOULD NOT BEGIN UNTIL AFTER MIDNIGHT. REGIONAL RADAR
COMPOSITES WERE SHOWING AN EXPANSION OF LIGHT RETURNS OVER WESTERN
IOWA THE PAST HOUR BETWEEN SOME HIGHER REFLECTIVITY/S MOVING
NORTHEAST OUT OF NORTH CENTRAL MO MORE SHOWERY LOOKING PRECIP FROM
NORTHERN IA INTO MN. THE CURRENT THINKING IS THE NORTHERN MO/IA
AREAS WILL MERGE THE NEXT FEW HOURS WITH THE BETTER FORCING AHEAD
OF THE NORTHERN PLAINS UPPER LOW MOVING IN.
NO OTHER CHANGES WERE MADE TO THE FORECAST CONCERNING SNOW FALL
AMOUNTS OR HEADLINES. THE 00Z NAM CAME IN WITH AN UPPER LOW TRACK
NORTHEAST OF THE MONDAYS RUNS SUGGESTING LOWER SNOW AMOUNTS...BUT
THE NAM HAS BEEN A NORTHEASTERN OUTLIER WITH THIS SYSTEM ON SEVERAL
RUNS. THE LATEST RAP RUNS CONTINUE TO MOVE THE UPPER LOW ALONG A
SIMILAR TRACK AS MONDAY/S MODEL RUNS SUGGESTED.
DLF
PREV DISCUSSION... /ISSUED 625 PM CST MON MAR 4 2013/
AVIATION...
A SURFACE TROF WILL DEVELOP OVER THE AREA OVERNIGHT AND THEN MOVE
SOUTH INTO MISSOURI BY LATE TUESDAY AFTERNOON. WIDESPSREAD SNOWS
ARE EXPECTED TO SPREAD OVER THE AREA TONIGHT WITH THE DEVELOPING
TROF THEN TAPER OFF TUESDAY AFTERNOON. NORTH TO NORTHWEST WINDS
WILL INCREASE LATE TUESDAY MORNING AND INTO THE AFTERNOON WITH
GUSTS AROUND 25KTS ESPECIALLY WEST OF THE MISSISSIPPI RIVER.
GENERALLY VFR WITH SOME PATCHY MVFR CIGS NORTH THIS EVENING WILL
GRADUALLY DETERIORATE BY LATE EVENING WITH WIDESPREAD MVFR CIGS IN
THE 1KFT TO 2KFT RANGE BY MIDNIGHT. SOME SCATTERED SNOW SHOWERS
NORTH OR RAIN/SNOW SHOWERS SOUTH ARE POSSIBLE DURING THE EVENING.
BY LATE EVENING IFR CIGS WILL BE POSSIBLE IN EAST CENTRAL IA.
AFTER MIDNIGHT COUNTDOWNS WILL RAPIDLY DETERIORATE TO IFR AND
LIFR AS THE SNOW SPREADS OVER THE AREA. THE LOWEST CONDITIONS WILL
LIKELY OCCUR BETWEEN 09Z AND 18Z DUE OBSCURED CEILINGS AND
MODERATE TO HEAVY SNOW REDUCING VISIBILITIES TO A HALF MILE OR
LESS AT TIMES. WINDS DURING THIS TIME WILL BE LIGHT.
THE SNOW SHOULD BE TAPERING OFF SOME DURING THE AFTERNOON BUT
NORTH TO NORTHWEST WINDS WILL BE INCREASING CAUSING CONSIDERABLE
BLOWING SNOW WHICH WILL CONTRIBUTE TO VISIBILITIES STAYING AROUND
A MILE THROUGH THE AFTERNOON.
DLF
PREV DISCUSSION... /ISSUED 352 PM CST MON MAR 4 2013/
DISCUSSION...
SHORT TERM...ASSESSING A PLETHORA OF PARAMETERS ON MANY OF THE
VARIOUS 12Z RUN MODELS...IT IS APPARENT THAT THERE IS SOMEWHAT
SOUTHWESTWARD ADJUSTMENT OF THE MID LEVEL LOW AS WELL AS LOW TO
MID LEVEL FORCING ALONG THE INCOMING VORT GRADIENT FLANK TARGETING
AREAS FROM NEAR VINTON IOWA...SOUTHEASTWARD TO THE NORTHERN QUAD
CITIES...AND THEN PUSHING EASTWARD ALONG THE I-80 CORRIDOR EAST OF
THE QUAD CITIES LATE TONIGHT AND TUESDAY. WITH SIGNALS OF A LOW TO MID
LEVEL TROWAL SIGNATURE WRAPPING BACK AROUND THE LOW-MID LEVEL
LOW/S AND LLVL INVERTED SFC TROF WITH PLENTY OF LLVL CONVERGENT
STAYING POWER LATE TONIGHT AND ESPECIALLY ON TUE...HAVE ADJUSTED
HIGHER SNOWFALL AMOUNTS MORE FROM NORTHWEST TO SOUTHEAST ACRS THE
NORTHEASTERN HALF OF THE DVN CWA. 7.5 TO 9.5 INCHES AND ISOLATED
10+ INCH AMOUNTS NOW LOOK POSSIBLE BY 00Z WED GENERALLY ALONG AND
EAST OF A LINE FROM INDEPENDENCE IA...TO THE QUAD CITIES...AND
CAMBRIDGE/HENRY CO IL. WIDESPREAD 5.5 UP TO 8 INCHES ALONG AND
NORTH OF I80 WEST OF THE QUAD CITIES TO THIS LINE. PIVOTING DEF
ZONE MAY FOCUS EVEN HIGHER AMOUNTS FROM EAST OF CEDAR
RAPIDS...THOUGH STERLING IL AND PRINCETON IL TUE AFTERNOON. 3 TO
6 INCH AMOUNTS SOUTH OF I80 TO THE HWY 34 CORRIDOR....AND 3-4
INCHES SOUTH OF HWY 34 ACRS THE REST OF THE SOUTHERN CWA. THESE
AMOUNTS DERIVED USING THE EXTENT OF MOISTURE INFLUX...LSR/S OF
13:1 TO 15:1 AND ACCEPTED FORCING AND LONG DURATION. THESE AMOUNTS
ARE JUST THOUGH 00Z. SOME ADDITIONAL ACCUMS PAST 00Z WED IN THE
EAST...SEE DISCUSSION BELOW.
SO ALL IN ALL...HAVE EXPANDED THE WARNING TO THE CENTRAL I80
CORRIDOR AND THEN EAST OF THE QUAD CITIES THROUGH PUTNAM CO IL.
HAVE SPLIT UP START TIMES WITH THE EAST HALF NOT UNTIL AFTER 06Z
TONIGHT THROUGH 06Z WED. ADVISORIES EXPANDED SOUTHWARD TO INCLUDE
THE ENTIRE CWA AS WELL. SPLIT THE ADVISORY FROM WEST TO EAST WITH
START TIMES OF 00Z WEST OF THE MS RVR...AND 06Z TO THE EAST. BUT
EVEN IN THE WESTERN ADVISORY AREA ACCUMULATING SNOW NOT LIKELY TO START
TIL AFTER 03Z-04Z TUE OR SO. SFC WINDS INCREASING TO 15 TO 25 MPH WITH
GUSTS UP T0 35 MPH WRAPPING AROUND DEPARTING SFC TROF AS TUE
PROGRESSES. THUS THE AFTERNOON AND EVENING THE PRIME TIME FOR
DRIFTING AND SOME BLOWING SNOW TO COMPOUND TRAVEL CONDITIONS.
ANOTHER REASON OF EXPANDING THE ADVISORIES SOUTHWARD ALONG WITH
SOME SNOWFALL ADJUSTMENT UPWARD IN THOSE SOUTHERN AREAS. ..12..
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...
HEADLINES...HAVE EXTENDED THE WARNINGS/ADVISORIES IN OUR EASTERN CWA
TO MIDNIGHT TUESDAY NIGHT TO COVER THE TAIL END OF THE WINTER STORM.
TUESDAY NIGHT...HIGH CONFIDENCE. ADDITIONAL ACCUMULATIONS IN OUR
EASTERN HALF CWA IN THE EVENING WILL BE AROUND AN INCH OR LESS.
HOWEVER...NORTH WINDS WILL BE GUSTING TO 25 TO 30 MPH. TEMPERATURES
DURING THE EVENING WILL BE IN THE 20S SO BLOWING AND DRIFTING WILL
ADD TO TRAVEL DIFFICULTIES. THIS IS THE REASON FOR EXTENDING THE
WARNING TO MIDNIGHT. AFTER MIDNIGHT THE SNOW SHOULD HAVE ENDED IN
OUR FAR EAST AND WINDS AND CLOUDS DECREASE OVERNIGHT AS THE SYSTEM
PUSHES WELL OFF TO OUR EAST. MINIMUM TEMPERATURES WILL BE IN THE
TEENS NORTH TO AROUND 20 SOUTH.
WEDNESDAY THROUGH FRIDAY...MEDIUM TO HIGH CONFIDENCE. THIS IS A DRY
PERIOD. WE START OUT COLD WEDNESDAY AND WEDNESDAY NIGHT WITH HIGH
PRESSURE OVER THE CWA. BUT THEN ZONAL FLOW AND MILDER TEMPERATURES
RETURN LATE IN THE WEEK. WITH HIGH PRESSURE PROVIDING MOSTLY CLEAR
SKIES AND LIGHT WINDS ON WEDNESDAY NIGHT I HAVE LOWERED TEMPERATURES
FROM PREVIOUS SHIFT. THIS IS ESPECIALLY TRUE WITH A FRESH SNOW PACK.
WILL FORECAST SINGLE DIGITS NORTH AND TEENS SOUTH BUT THIS MAY STILL
NOT BE COLD ENOUGH. IF WE ARE TOTALLY CLEAR AND WINDS ARE CALM SOME
LOCATIONS MAY DIP BELOW ZERO IN OUR FAR NORTH.
FRIDAY NIGHT THROUGH MONDAY...LOW CONFIDENCE. STRONG STORM SYSTEM
WILL BE TRACKING OUT OF THE SOUTHERN ROCKIES/SOUTHERN PLAINS AND
THEN INTO THE MIDWEST. HOWEVER...AS USUAL A WEEK AWAY THE MODELS ARE
HAVING DIFFICULTY WITH STRENGTH AND TIMING OF THE SYSTEM. THE GFS
SUGGESTS A WET WEEKEND BUT THE ECMWF HAS SLOWED THE SYSTEM FROM
PREVIOUS RUNS AND KEEP THINGS DRY UNTIL MONDAY. BASED ON CONSENSUS
MODEL DATA THE GRIDS WILL HAVE CHANCE POPS FOR SATURDAY THROUGH
MONDAY. HOWEVER LATER SHIFTS MAY EITHER NEED TO ADJUST OR ELIMINATE
POPS ONCE CONFIDENCE IN THE MODEL DATA INCREASES.
HAASE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER STORM WARNING UNTIL MIDNIGHT CST TUESDAY NIGHT FOR
CLINTON-DUBUQUE-JACKSON-MUSCATINE-SCOTT.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TUESDAY NIGHT FOR DES
MOINES-LOUISA.
WINTER STORM WARNING UNTIL 6 PM CST TUESDAY FOR BENTON-BUCHANAN-
CEDAR-DELAWARE-JOHNSON-JONES-LINN.
WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR HENRY IA-IOWA-
JEFFERSON-KEOKUK-LEE-VAN BUREN-WASHINGTON.
IL...WINTER STORM WARNING UNTIL MIDNIGHT CST TUESDAY NIGHT FOR BUREAU-
CARROLL-HENRY IL-JO DAVIESS-PUTNAM-ROCK ISLAND-STEPHENSON-
WHITESIDE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TUESDAY NIGHT FOR
HANCOCK-HENDERSON-MCDONOUGH-MERCER-WARREN.
MO...WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR CLARK-
SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1146 PM CST MON MAR 4 2013
...UPDATED FOR THE 06Z TAF AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 254 PM CST MON MAR 4 2013
WATER VAPOR AND HOURLY RAP ANALYSES SHOW A FAIRLY COMPACT JET STREAK
MOVING SOUTHEAST FROM IDAHO INTO COLORADO. THIS JET STREAK WAS WELL
TO THE SOUTHWEST OF THE MAIN UPPER LOW CENTER WHICH WAS CENTERED
ALONG THE WESTERN SOUTH DAKOTA-NORTH DAKOTA BORDER. THE FIRST
FRONTAL PASSAGE OCCURRED EARLIER IN THE DAY, BUT THE AIRMASS BEHIND
THIS FRONT WAS MAINLY DOWNSLOPE MODIFIED CONTINENTAL POLAR AIR...AND
NOT ARCTIC IN NATURE AT ALL. BECAUSE OF THIS...INSOLATION AND
CONTINUED DOWNSLOPE MODIFICATION YIELDED AFTERNOON TEMPERATURES
QUITE MILD AND RIGHT AROUND THE SEASONAL AVERAGE FOR EARLY MARCH.
THE EXCEPTION OF THIS WAS ACROSS SOUTH CENTRAL KANSAS WHERE
LINGERING SNOWPACK CONTINUED GENERALLY FROM HAYS TO KINSLEY TO
COLDWATER AND POINTS EAST (ESPECIALLY PRATT AND BARBER COUNTIES).
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 254 PM CST MON MAR 4 2013
LOWER-MID LEVEL CLOUD WILL CONTINUE TO INCREASE LATE THIS AFTERNOON
AND EVENING AS UPWARD VERTICAL MOTION INCREASES AHEAD OF THE
APPROACHING JET STREAK. RADAR ECHOES CONTINUED TO INCREASE ACROSS
NORTHEASTERN COLORADO AND AS THE UPPER JET STREAK APPROACHES WESTERN
KANSAS...FRONTOGENESIS IN THE MID TROPOSPHERE WILL FURTHER
INCREASE...AND RAIN/SNOW SHOWERS WILL INCREASE IN COVERAGE. POPS
WERE INCREASED TO THE 30-40 PERCENT ACROSS FAR WEST CENTRAL
KANSAS...AND THE CHALLENGE OF PRECIPITATION TYPE IS PRETTY HIGH
GIVEN THE RAPID COOLING OF THE 900-800MB LAYER EARLY THIS EVENING AS
THE SECOND COLD FRONT MOVES THROUGH AND EVAPORATIVE COOLING ENSUES.
THE INCREASING RADAR TRENDS ACROSS NORTHWEST KANSAS WOULD SUGGEST AN
INCREASE IN POPS ACROSS THE BOARD...SO BY PRESS TIME BEFORE 21Z WILL
HAVE POPS INCREASED AND SLIGHTLY HIGHER QPF AMOUNTS. THE PERIOD FROM
ROUGHLY 00Z TO 06Z WILL BE THE BEST TIME FRAME FOR LIGHT
ACCUMULATING PRECIPITATION AS THE 700MB FRONTOGENETIC MOVES QUICKLY
SOUTHEAST ACROSS WESTERN KANSAS. WILL BEGIN A RAPID CLEARING TREND
IN THE GRIDS TOWARD DAYBREAK TUESDAY. WE WILL REMAIN IN A FAIRLY
STRONG 850-700MB GRADIENT THROUGH MOST OF THE DAY TUESDAY WHICH WILL
KEEP WINDS UP IN THE BREEZY TO WINDY CATEGORY...BUT REMAINING BELOW
WIND ADVISORY CRITERIA AS IT LOOKS RIGHT NOW. HIGH TEMPERATURE
FORECAST WILL NOT BE CHANGED FROM THE GOING FORECAST WITH WIDESPREAD
LOWER TO MID 40S EXPECTED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CST MON MAR 4 2013
GOOD POTENTIAL EXISTS FOR COLDER TEMPERATURES OVERNIGHT TUESDAY
INTO EARLY WEDNESDAY MORNING. THE CENTER OF THE HIGH PRESSURE
SURFACE RIDGE AXIS WILL LIKELY BE CENTERED ACROSS CENTRAL KANSAS FOR
SEVERAL HOURS TUESDAY NIGHT. THIS WILL ALSO BE UNDER A VERY DRY DEEP
ATMOSPHERIC COLUMN, PROMOTING LONGWAVE RADIATIONAL COOLING.
SURFACE WINDS WILL QUICKLY TURN SOUTHEASTERLY ON THE WEST SIDE OF
THE RIDGE EARLY WEDNESDAY MORNING, AND EVEN BEFORE THAT ACROSS FAR
WESTERN KANSAS. THE MESOSCALE NAM INDICATES A POCKET OF THE COLDEST
POSSIBLE TEMPERATURES OF ALL MODEL OUTPUT AND MOS GUIDANCE. HOWEVER
IT APPEARS TO BE HAVING PROBLEMS ACCOUNTING FOR LEFTOVER SURFACE
SNOWDEPTH. THE ECMWF MOS APPEARS A GENERALLY REASONABLE BETTER
COMPROMISE IN THIS INSTANCE, AND WAS CLOSELY FOLLOWED WEDNESDAY
MORNING.
WEDNESDAY AFTERNOON WILL BRING WARMER TEMPERATURES, ESPECIALLY ACROSS
WESTERN KANSAS. THE NAM MODEL INDICATES A SHARP 850 MB LEVEL
TEMPERATURE GRADIENT ACROSS FROM AROUND DODGE CITY TO THE COLORADO
LINE, WITH SOUTHERLY SURFACE WINDS AROUND A DEVELOPING LEE SURFACE
LOW. EVEN WARMER BOUNDARY LAYER AIR WILL BE PRESENT EARLY BY
THURSDAY AFTERNOON. BY THURSDAY THE AXIS OF THE MID LEVEL THERMAL
RIDGE BECOMES CENTERED OVER THE HIGH PLAINS, AND THE SURFACE TROUGH
PULLS SLIGHTLY FARTHER EASTWARD, DRAWING IN WARMER AIR FROM THE
HIGHER TERRAIN OF SE COLORADO AND NE NEW MEXICO. WARMER OVERNIGHT
LOWS WILL BE EXPERIENCED AS WELL AS PERSISTENT SOUTHERLY WINDS
DURING THE OVERNIGHTS IN SLIGHTLY HIGHER THETA-E AIR. MELTING SNOW
IS LIKELY TO RE-FREEZE IN MOST CASES, AND IT IS NOT OBVIOUS AT THIS
POINT OF ANY NIGHTS APPEARING OVERLY PRONE TO DENSE FOG DEVELOPMENT.
A BETTER CHANCE FOR DENSE FOG WILL COME CLOSER TO THE BEGINNING OF
THE DYNAMIC LOW EXPECTED THIS WEEKEND STARTING AROUND FRIDAY.
LARGE UNCERTAINTY EXISTS WITH RESPECT TO THE STORM SYSTEM EXPECTED TO
INTENSIFY ACROSS THE CENTRAL HIGH PLAINS REGION BETWEEN FRIDAY AND
SUNDAY. THE ECMWF AND CANADIAN (GEM) MODELS ARE IN GENERALLY CLOSER
AGREEMENT TO ONE ANOTHER WITH A MORE BAROCLINIC SYSTEM, AS WELL AS
CONSIDERABLY SLOWER THAN THE GFS MODEL (BY AROUND 12 HOURS). THE
RECENT MODEL CONSENSUS, BLENDED WITH THE LAST FORECAST DOES LOWER
PROBABILITIES ON FRIDAY AND FRIDAY NIGHT, AND FOCUSES THE HIGHER
(LIKELY) CHANCES SATURDAY INTO SUNDAY. TEMPERATURES WILL ALSO BE A
CHALLENGE DURING THIS PERIOD. THE TRACK AND NATURE OF THE DYNAMIC
LOW WILL MAKE A LARGE DIFFERENCE, WITH A HIGH TEMPERATURE ENSEMBLE
SPREAD SATURDAY FROM THE LOW 40S TO LOW 60S. BETTER MODEL AGREEMENT
WILL BE LOOKED FOR AS THE SYSTEM BECOMES BETTER SAMPLED LATER IN THE
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1140 PM CST MON MAR 4 2013
THE REST OF TONIGHT WILL BE BREEZY WITH NORTH TO NORTHWEST WINDS
OF 15G25KT. VFR CONDITIONS WILL PREVAIL THROUGH THE 24 HOUR TAF
PERIOD. MID LEVEL CLOUDS IN THE BKN-OVC090-120 FOOT RANGE WILL
CONTINUE TO CLEAR TO THE EAST, LEAVING CLEAR SKIES BY 10Z. AS
HIGH PRESSURE BUILDS IN TUESDAY AFTERNOON, WINDS WILL DROP TO
LESS THAN 10 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 48 17 54 / 80 0 0 0
GCK 20 49 16 56 / 80 0 0 0
EHA 22 50 24 63 / 80 10 0 0
LBL 20 49 19 59 / 80 10 0 0
HYS 22 40 14 46 / 70 10 0 0
P28 25 42 16 49 / 30 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1212 PM EST TUE MAR 05 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1048 AM EST Tue Mar 5 2013
Did an update to adjust pops based on current radar trends. There
have been a few lightning strikes across far south central Kentucky,
so have kept the mention of a slight chance for thunderstorms in the
forecast. Otherwise, no major changes made.
&&
.Short Term (Now - Wednesday)...
Issued at 335 AM EST Tue Mar 5 2013
...Accumulating Snow Likely Tonight through Wed Morning...
A weak sfc low over Arkansas this morning will combine with a potent
upper low diving southeast across the Plains/Midwest to result in a
potent low pressure system strengthening over the Ohio Valley and
becoming nearly vertically stacked as it reaches the
Virginias/Carolinas by Wed afternoon. This system will be our main
focus for the next 24-36 hrs bringing rains and a few rumbles of
thunder today and then accumulating snow tonight into Wed.
Early this morning, good isentropic lift ahead of the aforementioned
sfc low was causing good rains to travel along and south of a sfc
trough over central KY. Thus, will continue 70-90% POPs through the
pre-dawn hours. The latest RAP guidance indicates that as the sfc
low moves into western KY around sunrise, we will start to see
precip become more isld-sct in nature for the rest of the morning
before ramping up again by early afternoon as the sfc low deepens
and moves through central KY. Also by late morning through early to
mid afternoon, an axis of instability with pass through south
central KY possible causing isld-sct embedded t-storms. T-storms
should remain relatively weak/elevated however.
The biggest threat with this weather system will arrive tonight as
the sfc low rapidly deepens in response to the arrival of the strong
upper low diving south into the Ohio Valley. This will create a
strong surge of cold air at the sfc with a trowal/comma head like
structure developing aloft. This setup will be favorable for
accumulating snows over southern Indiana and much of central KY.
Looking at soundings, rains should change over to snow from NW to SE
tonight between about 7-11 pm. Soundings suggest a decent period
during the overnight hours for accumulating snows especially over
southern Indiana and central KY along and north of I-64. Deep
moisture and combined with good forcing throughout the column should
could result in some moderate to heavy bands of snow overnight.
Overall think that 2-4 inches could accumulate overnight tonight
through Wed morning over much of southern Indiana and north
central/east central KY including the Louisville/Lexington metro
areas. South and east of this area, lesser amounts (up to 2 inches
would be most likely based on the latest model guidance. With these
advisory level snow accums in mind and the fact that snow will
likely be ongoing still during the Wed morning rush, went ahead and
decided to issue a Winter Wx Advy for this package which will run
from 0Z-18Z Wed. Adjustments to this advisory may need to be made
based on coming model runs today. Portions of southeast Indiana
and extreme northern KY may even stand a chance at 4+ inches of snow
accums, but did not feel confident enough in issuing anything more
than an winter wx advy at this point due to a pretty decent model
spread in snow accums. Drivers should plan extra travel time for
the Wed morning commute and use caution while driving in snow.
In addition to the snow for tonight into Wed morning, westerly winds
will gust into the 30-35 mph range especially during the pre-dawn
hours possibly resulting in some blowing snow. Winds should subside
somewhat by the rush hour however.
Highs today should reach the lower 40s to mid 50s. Lows tonight
should reach the upper 20s to around 20 degrees.
By late Wed morning or early afternoon, moisture will begin to pull
out of our area leaving isld snow showers or even just some
rain/drizzle on the back side as we lose ice crystals aloft and sfc
temps warm into the mid 30s for highs on Wed.
.Long Term (Wednesday Night through Monday)...
Issued at 255 AM EST Tue Mar 5 2013
Wednesday Night through Friday Night...
Current suite of deterministic and ensemble guidance is in pretty
good agreement through this portion of the forecast period. The
guidance suggest that the closed upper low will be exiting off the
US Mid-Atlantic coast at the beginning of the forecast period.
Upstream ridging to our west will gradually build into the region on
Thursday and Friday resulting in dry conditions along with a
moderating trend in temperatures. Cloudiness will likely be a
little to clear out Wednesday night as model time-height cross
sections show low-level moisture hanging around. More sufficient
clearing will take place on Thursday with partly cloudy skies and we
should see mostly sunny skies across the region on Friday.
Temperatures are a bit of a concern depending on how much snowfall
occurs with the Tuesday night/Wednesday system. For now have
trended the forecast a little on the cooler side of the guidance
envelope with upper 20s for lows Thursday morning. There is a bit
of spread in the guidance for Thursday. Feel that sticking close to
a blend of the ensemble guidance and the AllBlend (all model
consensus) is probably a good start at this point. Highs will range
from the lower-mid 40s in the north/northeastern sections with
middle 40s in the central and southwest sections. Lows Thursday
night and Friday morning should cool into the mid-upper 20s once
again due to good radiational cooling effects. Milder conditions
look likely for Friday with highs generally in the 50-55 degree
range with lows Friday night cooling into the lower 30s.
Saturday through Monday...
As we enter into the weekend, mid-level ridge axis is forecast to be
nearly overhead across the Ohio Valley as two large cutoff lows will
be to our east and west. This ridge axis should hold into Sunday as
well providing the area with mostly dry conditions along with milder
temperatures. Highs on Saturday have trended a little cooler in
tonight`s datasets. Still thinking that we`ll see highs in the
55-60 degree range on Saturday with highs in the lower 60s on
Sunday. Next weather maker looks to push into the region around
Monday as a large cutoff low pressure system out to our west slowly
churns eastward. There is a bit of spread between the more
progressive GFS solution and the slower Euro runs, for now have gone
closer to the Euro solution as the general model consensus is
usually too progressive/fast in the long term. Nonetheless, a
period of unsettled weather looks likely early next week along with
a cooldown in temperatures. Highs on Monday are likely to top out
in the upper 50s to the lower 60s.
&&
.Aviation (18Z TAF Issuance)...
Issued at 1210 PM EST Tue Mar 5 2013
The surface low is over central Kentucky early this afternoon. As it
moves east through the afternoon, rain will continue to overspread
the region. Currently all TAF sites have cigs under 500 ft. As
heavier rains spread over the area this afternoon and tonight they
may improve a bit, but in general look to stay around or under 1
kft. Visibilities will be up and down through the afternoon as well
depending on how heavy precipitation is at the time.
As this system shifts east colder air will quickly move in. The
precipitation will change over to a mix of rain and snow around 00Z,
then to all snow by 03Z or so. This snow may become heavier at times
at SDF and LEX overnight as banding sets up, reducing visibilities
and cigs even more. In addition, winds will become very gusty late
this afternoon and shift to westerly, then northwesterly. Gusts of
25-30 knots will be common overnight.
By daybreak tomorrow conditions should be improving at SDF and BWG
as the heaviest snow showers move off to the east.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR INZ076>079-083-084-
089>092.
KY...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR KYZ024-025-028>043-
045>049-053>057-064>067-077-078-081-082.
$$
Update...........EER
Short Term.......AMS
Long Term........MJ
Aviation.........EER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1049 AM EST TUE MAR 05 2013
.Forecast Update...
Issued at 1048 AM EST Tue Mar 5 2013
Did an update to adjust pops based on current radar trends. There
have been a few lightning strikes across far south central Kentucky,
so have kept the mention of a slight chance for thunderstorms in the
forecast. Otherwise, no major changes made.
&&
.Short Term (Now - Wednesday)...
Issued at 335 AM EST Tue Mar 5 2013
...Accumulating Snow Likely Tonight through Wed Morning...
A weak sfc low over Arkansas this morning will combine with a potent
upper low diving southeast across the Plains/Midwest to result in a
potent low pressure system strengthening over the Ohio Valley and
becoming nearly vertically stacked as it reaches the
Virginias/Carolinas by Wed afternoon. This system will be our main
focus for the next 24-36 hrs bringing rains and a few rumbles of
thunder today and then accumulating snow tonight into Wed.
Early this morning, good isentropic lift ahead of the aforementioned
sfc low was causing good rains to travel along and south of a sfc
trough over central KY. Thus, will continue 70-90% POPs through the
pre-dawn hours. The latest RAP guidance indicates that as the sfc
low moves into western KY around sunrise, we will start to see
precip become more isld-sct in nature for the rest of the morning
before ramping up again by early afternoon as the sfc low deepens
and moves through central KY. Also by late morning through early to
mid afternoon, an axis of instability with pass through south
central KY possible causing isld-sct embedded t-storms. T-storms
should remain relatively weak/elevated however.
The biggest threat with this weather system will arrive tonight as
the sfc low rapidly deepens in response to the arrival of the strong
upper low diving south into the Ohio Valley. This will create a
strong surge of cold air at the sfc with a trowal/comma head like
structure developing aloft. This setup will be favorable for
accumulating snows over southern Indiana and much of central KY.
Looking at soundings, rains should change over to snow from NW to SE
tonight between about 7-11 pm. Soundings suggest a decent period
during the overnight hours for accumulating snows especially over
southern Indiana and central KY along and north of I-64. Deep
moisture and combined with good forcing throughout the column should
could result in some moderate to heavy bands of snow overnight.
Overall think that 2-4 inches could accumulate overnight tonight
through Wed morning over much of southern Indiana and north
central/east central KY including the Louisville/Lexington metro
areas. South and east of this area, lesser amounts (up to 2 inches
would be most likely based on the latest model guidance. With these
advisory level snow accums in mind and the fact that snow will
likely be ongoing still during the Wed morning rush, went ahead and
decided to issue a Winter Wx Advy for this package which will run
from 0Z-18Z Wed. Adjustments to this advisory may need to be made
based on coming model runs today. Portions of southeast Indiana
and extreme northern KY may even stand a chance at 4+ inches of snow
accums, but did not feel confident enough in issuing anything more
than an winter wx advy at this point due to a pretty decent model
spread in snow accums. Drivers should plan extra travel time for
the Wed morning commute and use caution while driving in snow.
In addition to the snow for tonight into Wed morning, westerly winds
will gust into the 30-35 mph range especially during the pre-dawn
hours possibly resulting in some blowing snow. Winds should subside
somewhat by the rush hour however.
Highs today should reach the lower 40s to mid 50s. Lows tonight
should reach the upper 20s to around 20 degrees.
By late Wed morning or early afternoon, moisture will begin to pull
out of our area leaving isld snow showers or even just some
rain/drizzle on the back side as we lose ice crystals aloft and sfc
temps warm into the mid 30s for highs on Wed.
.Long Term (Wednesday Night through Monday)...
Issued at 255 AM EST Tue Mar 5 2013
Wednesday Night through Friday Night...
Current suite of deterministic and ensemble guidance is in pretty
good agreement through this portion of the forecast period. The
guidance suggest that the closed upper low will be exiting off the
US Mid-Atlantic coast at the beginning of the forecast period.
Upstream ridging to our west will gradually build into the region on
Thursday and Friday resulting in dry conditions along with a
moderating trend in temperatures. Cloudiness will likely be a
little to clear out Wednesday night as model time-height cross
sections show low-level moisture hanging around. More sufficient
clearing will take place on Thursday with partly cloudy skies and we
should see mostly sunny skies across the region on Friday.
Temperatures are a bit of a concern depending on how much snowfall
occurs with the Tuesday night/Wednesday system. For now have
trended the forecast a little on the cooler side of the guidance
envelope with upper 20s for lows Thursday morning. There is a bit
of spread in the guidance for Thursday. Feel that sticking close to
a blend of the ensemble guidance and the AllBlend (all model
consensus) is probably a good start at this point. Highs will range
from the lower-mid 40s in the north/northeastern sections with
middle 40s in the central and southwest sections. Lows Thursday
night and Friday morning should cool into the mid-upper 20s once
again due to good radiational cooling effects. Milder conditions
look likely for Friday with highs generally in the 50-55 degree
range with lows Friday night cooling into the lower 30s.
Saturday through Monday...
As we enter into the weekend, mid-level ridge axis is forecast to be
nearly overhead across the Ohio Valley as two large cutoff lows will
be to our east and west. This ridge axis should hold into Sunday as
well providing the area with mostly dry conditions along with milder
temperatures. Highs on Saturday have trended a little cooler in
tonight`s datasets. Still thinking that we`ll see highs in the
55-60 degree range on Saturday with highs in the lower 60s on
Sunday. Next weather maker looks to push into the region around
Monday as a large cutoff low pressure system out to our west slowly
churns eastward. There is a bit of spread between the more
progressive GFS solution and the slower Euro runs, for now have gone
closer to the Euro solution as the general model consensus is
usually too progressive/fast in the long term. Nonetheless, a
period of unsettled weather looks likely early next week along with
a cooldown in temperatures. Highs on Monday are likely to top out
in the upper 50s to the lower 60s.
&&
.Aviation (12Z TAF Issuance)...
Issued at 625 AM EST Tue Mar 5 2013
Isentropic lift ahead of an approaching sfc low has brought rain and
thickening low clouds to the area early this morning. Expect rain
to become less in coverage by 13-16Z across the area. MVFR
conditions look to prevail through the morning hours.
The aforementioned sfc low will move through central KY this
afternoon causing steady rains to pick up again by early afternoon.
Some models even indicate enough instability for a rumble of thunder
over south central KY. Did not include in BWG TAF due to low
confidence, but a VCTS is not out of the question. For this TAF
issuance, also backed off of IFR cigs as models have been too
aggressive bringing the lower cigs into the TAF sites. Will go
predominantly MVFR with a tempo group for IFR in moderate rain this
afternoon.
By late afternoon or early evening the sfc low will pass to our east
causing sfc winds to veer to the west and become gusty as colder air
rushes in. The latest models indicate a trowal/comma head like
structure on the back side of this weather system will bring
additional moisture in the from of -RASN then -SN tonight.
Accumulating snow will be possible especially at SDF/LEX which could
both see 1-4 inches by Wed morning. Cigs should stay in the low MVFR
cat overnight tonight with westerly winds gusting into the 25-30 kt
range.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR INZ076>079-083-084-
089>092.
KY...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR KYZ024-025-028>043-
045>049-053>057-064>067-077-078-081-082.
$$
Update...........EER
Short Term.......AMS
Long Term........MJ
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
653 AM EST TUE MAR 05 2013
.Forecast Update...
Issued at 650 AM EST Tue Mar 5 2013
Did a quick update to adjust POPs and thunder chances for the day.
Upstream radar imagery indicates morning rain will stick around
south central KY through mid morning. Also, downgraded t-storm
chances to isld as 0Z and 6Z soundings look pretty pessimistic as
far as getting much embedded thunder this afternoon.
&&
.Short Term (Now - Wednesday)...
Issued at 335 AM EST Tue Mar 5 2013
...Accumulating Snow Likely Tonight through Wed Morning...
A weak sfc low over Arkansas this morning will combine with a potent
upper low diving southeast across the Plains/Midwest to result in a
potent low pressure system strengthening over the Ohio Valley and
becoming nearly vertically stacked as it reaches the
Virginias/Carolinas by Wed afternoon. This system will be our main
focus for the next 24-36 hrs bringing rains and a few rumbles of
thunder today and then accumulating snow tonight into Wed.
Early this morning, good isentropic lift ahead of the aforementioned
sfc low was causing good rains to travel along and south of a sfc
trough over central KY. Thus, will continue 70-90% POPs through the
pre-dawn hours. The latest RAP guidance indicates that as the sfc
low moves into western KY around sunrise, we will start to see
precip become more isld-sct in nature for the rest of the morning
before ramping up again by early afternoon as the sfc low deepens
and moves through central KY. Also by late morning through early to
mid afternoon, an axis of instability with pass through south
central KY possible causing isld-sct embedded t-storms. T-storms
should remain relatively weak/elevated however.
The biggest threat with this weather system will arrive tonight as
the sfc low rapidly deepens in response to the arrival of the strong
upper low diving south into the Ohio Valley. This will create a
strong surge of cold air at the sfc with a trowal/comma head like
structure developing aloft. This setup will be favorable for
accumulating snows over southern Indiana and much of central KY.
Looking at soundings, rains should change over to snow from NW to SE
tonight between about 7-11 pm. Soundings suggest a decent period
during the overnight hours for accumulating snows especially over
southern Indiana and central KY along and north of I-64. Deep
moisture and combined with good forcing throughout the column should
could result in some moderate to heavy bands of snow overnight.
Overall think that 2-4 inches could accumulate overnight tonight
through Wed morning over much of southern Indiana and north
central/east central KY including the Louisville/Lexington metro
areas. South and east of this area, lesser amounts (up to 2 inches
would be most likely based on the latest model guidance. With these
advisory level snow accums in mind and the fact that snow will
likely be ongoing still during the Wed morning rush, went ahead and
decided to issue a Winter Wx Advy for this package which will run
from 0Z-18Z Wed. Adjustments to this advisory may need to be made
based on coming model runs today. Portions of southeast Indiana
and extreme northern KY may even stand a chance at 4+ inches of snow
accums, but did not feel confident enough in issuing anything more
than an winter wx advy at this point due to a pretty decent model
spread in snow accums. Drivers should plan extra travel time for
the Wed morning commute and use caution while driving in snow.
In addition to the snow for tonight into Wed morning, westerly winds
will gust into the 30-35 mph range especially during the pre-dawn
hours possibly resulting in some blowing snow. Winds should subside
somewhat by the rush hour however.
Highs today should reach the lower 40s to mid 50s. Lows tonight
should reach the upper 20s to around 20 degrees.
By late Wed morning or early afternoon, moisture will begin to pull
out of our area leaving isld snow showers or even just some
rain/drizzle on the back side as we lose ice crystals aloft and sfc
temps warm into the mid 30s for highs on Wed.
.Long Term (Wednesday Night through Monday)...
Issued at 255 AM EST Tue Mar 5 2013
Wednesday Night through Friday Night...
Current suite of deterministic and ensemble guidance is in pretty
good agreement through this portion of the forecast period. The
guidance suggest that the closed upper low will be exiting off the
US Mid-Atlantic coast at the beginning of the forecast period.
Upstream ridging to our west will gradually build into the region on
Thursday and Friday resulting in dry conditions along with a
moderating trend in temperatures. Cloudiness will likely be a
little to clear out Wednesday night as model time-height cross
sections show low-level moisture hanging around. More sufficient
clearing will take place on Thursday with partly cloudy skies and we
should see mostly sunny skies across the region on Friday.
Temperatures are a bit of a concern depending on how much snowfall
occurs with the Tuesday night/Wednesday system. For now have
trended the forecast a little on the cooler side of the guidance
envelope with upper 20s for lows Thursday morning. There is a bit
of spread in the guidance for Thursday. Feel that sticking close to
a blend of the ensemble guidance and the AllBlend (all model
consensus) is probably a good start at this point. Highs will range
from the lower-mid 40s in the north/northeastern sections with
middle 40s in the central and southwest sections. Lows Thursday
night and Friday morning should cool into the mid-upper 20s once
again due to good radiational cooling effects. Milder conditions
look likely for Friday with highs generally in the 50-55 degree
range with lows Friday night cooling into the lower 30s.
Saturday through Monday...
As we enter into the weekend, mid-level ridge axis is forecast to be
nearly overhead across the Ohio Valley as two large cutoff lows will
be to our east and west. This ridge axis should hold into Sunday as
well providing the area with mostly dry conditions along with milder
temperatures. Highs on Saturday have trended a little cooler in
tonight`s datasets. Still thinking that we`ll see highs in the
55-60 degree range on Saturday with highs in the lower 60s on
Sunday. Next weather maker looks to push into the region around
Monday as a large cutoff low pressure system out to our west slowly
churns eastward. There is a bit of spread between the more
progressive GFS solution and the slower Euro runs, for now have gone
closer to the Euro solution as the general model consensus is
usually too progressive/fast in the long term. Nonetheless, a
period of unsettled weather looks likely early next week along with
a cooldown in temperatures. Highs on Monday are likely to top out
in the upper 50s to the lower 60s.
&&
.Aviation (12Z TAF Issuance)...
Issued at 625 AM EST Tue Mar 5 2013
Isentropic lift ahead of an approaching sfc low has brought rain and
thickening low clouds to the area early this morning. Expect rain
to become less in coverage by 13-16Z across the area. MVFR
conditions look to prevail through the morning hours.
The aforementioned sfc low will move through central KY this
afternoon causing steady rains to pick up again by early afternoon.
Some models even indicate enough instability for a rumble of thunder
over south central KY. Did not include in BWG TAF due to low
confidence, but a VCTS is not out of the question. For this TAF
issuance, also backed off of IFR cigs as models have been too
aggressive bringing the lower cigs into the TAF sites. Will go
predominantly MVFR with a tempo group for IFR in moderate rain this
afternoon.
By late afternoon or early evening the sfc low will pass to our east
causing sfc winds to veer to the west and become gusty as colder air
rushes in. The latest models indicate a trowal/comma head like
structure on the back side of this weather system will bring
additional moisture in the from of -RASN then -SN tonight.
Accumulating snow will be possible especially at SDF/LEX which could
both see 1-4 inches by Wed morning. Cigs should stay in the low MVFR
cat overnight tonight with westerly winds gusting into the 25-30 kt
range.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR INZ076>079-083-084-
089>092.
KY...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR KYZ024-025-028>043-
045>049-053>057-064>067-077-078-081-082.
$$
Update...........AMS
Short Term.......AMS
Long Term........MJ
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
626 AM EST TUE MAR 05 2013
...Updated Aviation Discussion...
.Short Term (Now - Wednesday)...
Issued at 335 AM EST Tue Mar 5 2013
...Accumulating Snow Likely Tonight through Wed Morning...
A weak sfc low over Arkansas this morning will combine with a potent
upper low diving southeast across the Plains/Midwest to result in a
potent low pressure system strengthening over the Ohio Valley and
becoming nearly vertically stacked as it reaches the
Virginias/Carolinas by Wed afternoon. This system will be our main
focus for the next 24-36 hrs bringing rains and a few rumbles of
thunder today and then accumulating snow tonight into Wed.
Early this morning, good isentropic lift ahead of the aforementioned
sfc low was causing good rains to travel along and south of a sfc
trough over central KY. Thus, will continue 70-90% POPs through the
pre-dawn hours. The latest RAP guidance indicates that as the sfc
low moves into western KY around sunrise, we will start to see
precip become more isld-sct in nature for the rest of the morning
before ramping up again by early afternoon as the sfc low deepens
and moves through central KY. Also by late morning through early to
mid afternoon, an axis of instability with pass through south
central KY possible causing isld-sct embedded t-storms. T-storms
should remain relatively weak/elevated however.
The biggest threat with this weather system will arrive tonight as
the sfc low rapidly deepens in response to the arrival of the strong
upper low diving south into the Ohio Valley. This will create a
strong surge of cold air at the sfc with a trowal/comma head like
structure developing aloft. This setup will be favorable for
accumulating snows over southern Indiana and much of central KY.
Looking at soundings, rains should change over to snow from NW to SE
tonight between about 7-11 pm. Soundings suggest a decent period
during the overnight hours for accumulating snows especially over
southern Indiana and central KY along and north of I-64. Deep
moisture and combined with good forcing throughout the column should
could result in some moderate to heavy bands of snow overnight.
Overall think that 2-4 inches could accumulate overnight tonight
through Wed morning over much of southern Indiana and north
central/east central KY including the Louisville/Lexington metro
areas. South and east of this area, lesser amounts (up to 2 inches
would be most likely based on the latest model guidance. With these
advisory level snow accums in mind and the fact that snow will
likely be ongoing still during the Wed morning rush, went ahead and
decided to issue a Winter Wx Advy for this package which will run
from 0Z-18Z Wed. Adjustments to this advisory may need to be made
based on coming model runs today. Portions of southeast Indiana
and extreme northern KY may even stand a chance at 4+ inches of snow
accums, but did not feel confident enough in issuing anything more
than an winter wx advy at this point due to a pretty decent model
spread in snow accums. Drivers should plan extra travel time for
the Wed morning commute and use caution while driving in snow.
In addition to the snow for tonight into Wed morning, westerly winds
will gust into the 30-35 mph range especially during the pre-dawn
hours possibly resulting in some blowing snow. Winds should subside
somewhat by the rush hour however.
Highs today should reach the lower 40s to mid 50s. Lows tonight
should reach the upper 20s to around 20 degrees.
By late Wed morning or early afternoon, moisture will begin to pull
out of our area leaving isld snow showers or even just some
rain/drizzle on the back side as we lose ice crystals aloft and sfc
temps warm into the mid 30s for highs on Wed.
.Long Term (Wednesday Night through Monday)...
Issued at 255 AM EST Tue Mar 5 2013
Wednesday Night through Friday Night...
Current suite of deterministic and ensemble guidance is in pretty
good agreement through this portion of the forecast period. The
guidance suggest that the closed upper low will be exiting off the
US Mid-Atlantic coast at the beginning of the forecast period.
Upstream ridging to our west will gradually build into the region on
Thursday and Friday resulting in dry conditions along with a
moderating trend in temperatures. Cloudiness will likely be a
little to clear out Wednesday night as model time-height cross
sections show low-level moisture hanging around. More sufficient
clearing will take place on Thursday with partly cloudy skies and we
should see mostly sunny skies across the region on Friday.
Temperatures are a bit of a concern depending on how much snowfall
occurs with the Tuesday night/Wednesday system. For now have
trended the forecast a little on the cooler side of the guidance
envelope with upper 20s for lows Thursday morning. There is a bit
of spread in the guidance for Thursday. Feel that sticking close to
a blend of the ensemble guidance and the AllBlend (all model
consensus) is probably a good start at this point. Highs will range
from the lower-mid 40s in the north/northeastern sections with
middle 40s in the central and southwest sections. Lows Thursday
night and Friday morning should cool into the mid-upper 20s once
again due to good radiational cooling effects. Milder conditions
look likely for Friday with highs generally in the 50-55 degree
range with lows Friday night cooling into the lower 30s.
Saturday through Monday...
As we enter into the weekend, mid-level ridge axis is forecast to be
nearly overhead across the Ohio Valley as two large cutoff lows will
be to our east and west. This ridge axis should hold into Sunday as
well providing the area with mostly dry conditions along with milder
temperatures. Highs on Saturday have trended a little cooler in
tonight`s datasets. Still thinking that we`ll see highs in the
55-60 degree range on Saturday with highs in the lower 60s on
Sunday. Next weather maker looks to push into the region around
Monday as a large cutoff low pressure system out to our west slowly
churns eastward. There is a bit of spread between the more
progressive GFS solution and the slower Euro runs, for now have gone
closer to the Euro solution as the general model consensus is
usually too progressive/fast in the long term. Nonetheless, a
period of unsettled weather looks likely early next week along with
a cooldown in temperatures. Highs on Monday are likely to top out
in the upper 50s to the lower 60s.
&&
.Aviation (12Z TAF Issuance)...
Issued at 625 AM EST Tue Mar 5 2013
Isentropic lift ahead of an approaching sfc low has brought rain and
thickening low clouds to the area early this morning. Expect rain
to become less in coverage by 13-16Z across the area. MVFR
conditions look to prevail through the morning hours.
The aforementioned sfc low will move through central KY this
afternoon causing steady rains to pick up again by early afternoon.
Some models even indicate enough instability for a rumble of thunder
over south central KY. Did not include in BWG TAF due to low
confidence, but a VCTS is not out of the question. For this TAF
issuance, also backed off of IFR cigs as models have been too
aggressive bringing the lower cigs into the TAF sites. Will go
predominantly MVFR with a tempo group for IFR in moderate rain this
afternoon.
By late afternoon or early evening the sfc low will pass to our east
causing sfc winds to veer to the west and become gusty as colder air
rushes in. The latest models indicate a trowal/comma head like
structure on the back side of this weather system will bring
additional moisture in the from of -RASN then -SN tonight.
Accumulating snow will be possible especially at SDF/LEX which could
both see 1-4 inches by Wed morning. Cigs should stay in the low MVFR
cat overnight tonight with westerly winds gusting into the 25-30 kt
range.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR INZ076>079-083-084-
089>092.
KY...WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO
1 PM EST /NOON CST/ WEDNESDAY FOR KYZ024-025-028>043-
045>049-053>057-064>067-077-078-081-082.
$$
Short Term.......AMS
Long Term........MJ
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
337 AM EST TUE MAR 05 2013
.Short Term (Now - Wednesday)...
Issued at 335 AM EST Tue Mar 5 2013
...Accumulating Snow Likely Tonight through Wed Morning...
A weak sfc low over Arkansas this morning will combine with a potent
upper low diving southeast across the Plains/Midwest to result in a
potent low pressure system strengthening over the Ohio Valley and
becoming nearly vertically stacked as it reaches the
Virginias/Carolinas by Wed afternoon. This system will be our main
focus for the next 24-36 hrs bringing rains and a few rumbles of
thunder today and then accumulating snow tonight into Wed.
Early this morning, good isentropic lift ahead of the aforementioned
sfc low was causing good rains to travel along and south of a sfc
trough over central KY. Thus, will continue 70-90% POPs through the
pre-dawn hours. The latest RAP guidance indicates that as the sfc
low moves into western KY around sunrise, we will start to see
precip become more isld-sct in nature for the rest of the morning
before ramping up again by early afternoon as the sfc low deepens
and moves through central KY. Also by late morning through early to
mid afternoon, an axis of instability with pass through south
central KY possible causing isld-sct embedded t-storms. T-storms
should remain relatively weak/elevated however.
The biggest threat with this weather system will arrive tonight as
the sfc low rapidly deepens in response to the arrival of the strong
upper low diving south into the Ohio Valley. This will create a
strong surge of cold air at the sfc with a trowal/comma head like
structure developing aloft. This setup will be favorable for
accumulating snows over southern Indiana and much of central KY.
Looking at soundings, rains should change over to snow from NW to SE
tonight between about 7-11 pm. Soundings suggest a decent period
during the overnight hours for accumulating snows especially over
southern Indiana and central KY along and north of I-64. Deep
moisture and combined with good forcing throughout the column should
could result in some moderate to heavy bands of snow overnight.
Overall think that 2-4 inches could accumulate overnight tonight
through Wed morning over much of southern Indiana and north
central/east central KY including the Louisville/Lexington metro
areas. South and east of this area, lesser amounts (up to 2 inches
would be most likely based on the latest model guidance. With these
advisory level snow accums in mind and the fact that snow will
likely be ongoing still during the Wed morning rush, went ahead and
decided to issue a Winter Wx Advy for this package which will run
from 0Z-18Z Wed. Adjustments to this advisory may need to be made
based on coming model runs today. Portions of southeast Indiana
and extreme northern KY may even stand a chance at 4+ inches of snow
accums, but did not feel confident enough in issuing anything more
than an winter wx advy at this point due to a pretty decent model
spread in snow accums. Drivers should plan extra travel time for
the Wed morning commute and use caution while driving in snow.
In addition to the snow for tonight into Wed morning, westerly winds
will gust into the 30-35 mph range especially during the pre-dawn
hours possibly resulting in some blowing snow. Winds should subside
somewhat by the rush hour however.
Highs today should reach the lower 40s to mid 50s. Lows tonight
should reach the upper 20s to around 20 degrees.
By late Wed morning or early afternoon, moisture will begin to pull
out of our area leaving isld snow showers or even just some
rain/drizzle on the back side as we lose ice crystals aloft and sfc
temps warm into the mid 30s for highs on Wed.
.Long Term (Wednesday Night through Monday)...
Issued at 255 AM EST Tue Mar 5 2013
Wednesday Night through Friday Night...
Current suite of deterministic and ensemble guidance is in pretty
good agreement through this portion of the forecast period. The
guidance suggest that the closed upper low will be exiting off the
US Mid-Atlantic coast at the beginning of the forecast period.
Upstream ridging to our west will gradually build into the region on
Thursday and Friday resulting in dry conditions along with a
moderating trend in temperatures. Cloudiness will likely be a
little to clear out Wednesday night as model time-height cross
sections show low-level moisture hanging around. More sufficient
clearing will take place on Thursday with partly cloudy skies and we
should see mostly sunny skies across the region on Friday.
Temperatures are a bit of a concern depending on how much snowfall
occurs with the Tuesday night/Wednesday system. For now have
trended the forecast a little on the cooler side of the guidance
envelope with upper 20s for lows Thursday morning. There is a bit
of spread in the guidance for Thursday. Feel that sticking close to
a blend of the ensemble guidance and the AllBlend (all model
consensus) is probably a good start at this point. Highs will range
from the lower-mid 40s in the north/northeastern sections with
middle 40s in the central and southwest sections. Lows Thursday
night and Friday morning should cool into the mid-upper 20s once
again due to good radiational cooling effects. Milder conditions
look likely for Friday with highs generally in the 50-55 degree
range with lows Friday night cooling into the lower 30s.
Saturday through Monday...
As we enter into the weekend, mid-level ridge axis is forecast to be
nearly overhead across the Ohio Valley as two large cutoff lows will
be to our east and west. This ridge axis should hold into Sunday as
well providing the area with mostly dry conditions along with milder
temperatures. Highs on Saturday have trended a little cooler in
tonight`s datasets. Still thinking that we`ll see highs in the
55-60 degree range on Saturday with highs in the lower 60s on
Sunday. Next weather maker looks to push into the region around
Monday as a large cutoff low pressure system out to our west slowly
churns eastward. There is a bit of spread between the more
progressive GFS solution and the slower Euro runs, for now have gone
closer to the Euro solution as the general model consensus is
usually too progressive/fast in the long term. Nonetheless, a
period of unsettled weather looks likely early next week along with
a cooldown in temperatures. Highs on Monday are likely to top out
in the upper 50s to the lower 60s.
&&
.Aviation (06Z TAF Issuance)...
Issued at 1235 AM EST Tue Mar 5 2013
Isentropic lift ahead of an approaching sfc low will bring rain
showers and thickening low clouds to the area early this morning.
Expect rain showers to begin at the TAF sites within the next 1-3
hrs with MVFR cigs arriving just before sunrise according the 0Z NAM
soundings and gridded LAMP guidance. It`s not totally out of the
question that BWG could see a rumble of thunder as well, but not
confident enough to put in the TAF at this time as lightning obs
upstream remain very sparse.
The sfc low will move through central KY this afternoon. While we
may see a lull in or widely scattered rain shower activity during
the mid to late morning hours across the area, steady rains should
again pick up by early afternoon. Most models are picking up the
arrival of IFR cigs before the main push of rain. While this may be
possible, have generally delayed lower cigs in the first 6 hours of
the TAFs so IFR after sunrise may be delayed as well. Will need to
monitor this morning.
By late afternoon or early evening the sfc low will pass to our east
causing sfc winds to veer to the west and become gusty as colder air
rushes in. The latest models indicate a trowal/comma head like
structure on the back side of this weather system will bring
additional moisture in the from of -RASN then -SN tonight. Cigs
should improve to low MVFR levels by this evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......AMS
Long Term........MJ
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1000 PM EST WED MAR 6 2013
.SYNOPSIS...
DEEPENING LOW PRESSURE WILL CONTINUE TO MOVE OUT TO SEA TONIGHT
THROUGH THURSDAY. HIGH PRESSURE SLOWLY BUILDS INTO THE AREA FROM
THURSDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
SFC LO PRES NOW JUST OFF THE ERN SHORE OF VA...AND WILL CONT TO
SLO DRIFT OFFSHR THROUGH THE OVRNGT. COLDER AIR RIGHT BEHIND THE
STM IS HAVING DIFFICULTY MOVING OVR THE ERN PORTION OF THE FA
RIGHT NOW...AND WILL RMN SLO TO DO SO INTO/THROUGH THE (ERY) EVE.
INLAND...COLDER AIR HAS MANAGED TO CHANGE PCPN TO SN FOR A WHILE
FOR MUCH OF CNTRL/WRN AND SRN PORTIONS OF FA. PCPN RATE HAS CONTD
TO DCRS THROUGH THE AFTN ON THE NW AND W SIDE OF THE STM AND W/
TEMPS IN THE (M/U)30S...RA HAS BEEN MIXED W/ THE WET SN. ACCUMS ARE
GENLY OVR...RMNG BLO 1 INCH FOR MANY LOCATIONS. ONE AREA OF CONTD
CONCERN IS OVR THE LWR MD ERN SHR TNGT...THOUGH THERE IS CONCERN
ABT ENOUGH COLD AIR TO BE BROUGHT INTO THE AREA TO CHANGE THE PCPN
OVR TO ACCUM SN.
HAVE LWRD WINTER WARNING TO ADVSRY...AND WILL LEAVE ADVSRY FOR THE
OTHER AREAS THROUGH THE EVE HRS (THROUGH OVRNGT ON THE LWR MD ERN
SHR...THOUGH LWRD ACCUMS TO 1-2 INCH).
ADDITIONALLY...NNW WNDS WILL RMN GUSTY TO 35 TO 50 MPH...ESP FM
I95 TO THE CST. WIND ADVSRY RMNS IN PLACE FOR ERN VA/LWR MD AND
CSTL NE NC.
PCPN WINDS DOWN LT EVE/OVRNGT...W/ LO TEMPS NR/SLGTLY BLO
FRZG...MAY HAVE SLUSH REFREEZE FM RIC N AND W. MOST LO TEMPS TNGT
FM THE U20S W TO M30S E.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
LO PRES CONTS TO MOVE OUT TO SEA THU THROUGH SAT. A SECOND S/W
DIVING SSE FM WRN NEW ENG/NY STATE ON FRI PSBLY RESULTING IN
BKN/OVC CLDNS (ESP E OF I 95) AND ISOLD/SCT PCPN. NNW WINDS WILL
RMN GUSTY AS WELL...ESP NR THE CST...THROUGH FRI. SFC HI PRES IS
SLO TO BUILD SWD INTO THE MDATLC RGN BY SAT...FINALLY RESULTING IN
DRY WX FOR ALL AREAS.
P/MCLDY TNGT...THEN PCLDY OR VRB CLDNS THU. PCLDY W/MCLDY E THU
NGT THROUGH FRI...THEN MSTLY SKC ON SAT. HI TEMPS RANGING THROUGH
THE 40S N AND CNTRL AREAS...TO L50S S THU/FRI...THEN FM THE U40S
TO M50S SAT. LO TEMPS IN THE U20S TO L30S THU/FRI NGTS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GOING WITH A COMBINATION OF THE 12Z GFS/ECMWF FOR THE EXTENDED
PERIOD...ESPLY WITH REGARD TO TIMING OF APPROACH AND PASSAGE OF COLD
FRONT MON NGT THRU TUE. UA RDG/LRG AREA OF SFC HI PRES WILL PROVIDE
DRY WX SAT NGT INTO MON MORNG. LO PRES AND ASSOC COLD FRONT WILL
THEN AFFECT THE REGION MON EVENG THRU TUE...WITH DECENT CHC FOR
SHOWERS. MILDER TEMPS EXPECTED SUN INTO TUE. DRY WX RETURNS FOR TUE
NGT THRU WED...AS HI PRES WILL GRADUALLY BLD IN FM THE NW. MIN TEMPS
WILL BE IN THE LWR TO MID 30S SUN MORNG...IN THE UPR 30S TO LWR 40S
MON MORNG...IN THE 40S TUE MORNG...AND IN THE MID 30S TO ARND 40 WED
MORNG. MAX TEMPS WILL BE IN THE MID 50S TO LWR 60S SUN...IN THE LWR
TO MID 60S MON...IN THE MID 50S TO LWR 60S TUE...AND IN THE MID TO
UPR 50S WED.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE HAS MOVED OFF THE VA/NC COAST AND STRONG WINDS ARE
GUSTING FROM THE N/NNW AT ALL TAF SITES. GUSTS TO 40-45 KT REMAIN
PSBL AT TIMES THROUGH THE OVERNIGHT HOURS...ESPECIALLY ALONG THE COAST.
RAIN AND SNOW WILL TAPER OFF TONIGHT. CIGS AND VSBYS WILL CONTINUE
TO BE IN AND OUT OF IFR CONDS WITH MAINLY IFR ON THE BACKSIDE OF
THE LOW. PCPN ENDS AND DRYING WILL ALLOW CIGS TO IMPROVE AFT 05Z.
VFR CONDS ARE EXPECTED TOWARD MORNING WITH WINDS GUSTING TO 25KT
IN THE AFTN.
THE LOW WILL CONTINUE TO SLOWLY PUSH OFFSHORE ALLOWING HIGH PRESSURE
TO BUILD IN FROM THE NW. FAIR WEATHER/VFR CONDITIONS WILL PREVAIL
INTO EARLY NEXT WEEK WITH GUSTY WINDS CONTINUING DUE TO THE STRONG
PRESSURE GRADIENT THAT WILL REMAIN OVER THE AREA.
&&
.MARINE...
UPDATE: HAVE HOISTED STORM WARNING FOR ATLANTIC COASTAL WATERS
NORTH OF VA/NC BORDER. HAVE BEEN HANDLING WITH SPECIAL MARINE
WARNINGS THUS FAR, BUT WITH HRRR SHOWING THIS SURGE LASTING A FEW
HOURS LONGER, FEEL A BIT MORE COMFORTABLE HOISTING STORM HEADLINE
THROUGH 2AM, WITH A PERIOD OF GALES LIKELY AFTER WINDS DIMINISH
SOME AFTER MIDNIGHT. OTHERWISE, HAVE DROPPED GALES OVER THE RIVERS
TO SCA...IN EFFECT UNTIL MORNING.
PREVIOUS DISCUSSION....
A STRENGTHENING SFC LOW PRESSURE WILL ROTATE OVER THE MID
ATLANTIC COAST THIS EVENING...THEN PUSH OUT TO SEA OVERNIGHT.
WIND DIRECTIONS ARE PRIMARILY N LATE THIS AFTN AND WILL BECOME
MORE NWLY AS THE EVENING PROGRESSES. A NRLY SURGE HAS BEGUN OVER
NRN CHES BAY AND WILL CONTINUE TO PUSH SWD THROUGH THE EVENING.
CURRENT FORECAST ALREADY HAS THIS TREND IN PLACE. FOR COASTAL
WATERS N OF CHINCOTEAGUE...A STORM WARNING HAS BEEN ISSUED THROUGH
EARLY THU MORNING AS THE NRLY SURGE COMMENCES LATE THIS AFTN INTO
THE EVENING AND GUSTS REACH 50-55 KT. IN ADDITION...GALE WARNINGS
HAVE BEEN ISSUED FOR THE RIVERS TO ACCOUNT FOR THE NRLY SURGE AND
FOR WHEN WINDS BECOME NWLY...WHICH IS A FAVORABLE ORIENTATION FOR
STRONG WINDS TO OCCUR. GALES ARE EXPECTED TO FALL BELOW 34 KT AT
VARIOUS TIMES TONIGHT AND THU MORNING...AND WILL BE REPLACED BY
SOLID SCA FLAGS AS DEEMED NECESSARY. SEAS ARE ANYWHERE FROM 10-19
FEET N OF CAPE CHARLES AND 5-9 FT S OF CAPE CHARLES. THEY SHOULD
STAY ELEVATED THROUGH THU MORNING AND THEN FALL VERY SLOWLY
THROUGH THE REST OF THE WEEK.
AS THE SFC LOW PUSHES EAST OF LONGITUDE 70W LATE THU NIGHT INTO
FRI...THE PRESSURE GRADIENT REMAINS TIGHT AND A SECONDARY SHORTWAVE
FEATURE MOVES SE ACROSS THE WATERS. THIS FEATURE WILL BRING A
REINFORCING SHOT OF COLD AIR INTO THE REGION AND THE SUBSEQUENT CAA
WILL PRODUCE ANOTHER ROUND OF SOLID SCA CONDITIONS (POSSIBLY GALES
OVER COASTAL WATERS) THU NIGHT INTO FRI MORNING. WINDS THEN SHIFT TO
THE N FRI NIGHT AND HIGH PRESSURE BEGINS TO BUILD INTO THE AREA FROM
NW...BRINGING MORE QUIET CONDITIONS TO AREA WATERS THROUGH THE
WEEKEND.
&&
.TIDES/COASTAL FLOODING...
UPDATE...COASTAL FLOOD WARNING HAS BEEN UPDATED TO RUN THROUGH
EARLY FRIDAY OVER ALL COASTAL AREAS NORTH OF VA/NC BORDER, WITH
THE EXCEPTION OF LANCASTER/NORTHUMBERLAND COUNTIES, WHERE SLIGHTLY
LOWER WATER LEVELS NECESSITATES ONLY AN ADVISORY. TIDAL DEPARTURES
ON THE ORDER OF 2.5 TO 4 FT ABOVE NORMAL HAVE LED TO MODERATE
COASTAL FLOODING IMPACTS ALREADY OVER MUCH OF THIS AREA, WITH
ADDITIONAL ANOMALIES EXPECTED TONIGHT AND OVERNIGHT. MDL AND CBOFS
GUIDANCE HAVE BOTH UNDERESTIMATED THIS NORTHERLY SURGE THIS
EVENING, AND HAVE SIDED CLOSE TO/JUST ABV VIMS GUIDANCE FOR THIS
PACKAGE, AS IT APPEARS TO BE THE MOST ACCURATE IN DEPICTING TIDAL
LEVELS OCCURRING RIGHT NOW. THIS GUIDANCE INDICATING ANOTHER TIDE
CYCLE BETWEEN 2.5 TO 4 FT ABOVE NORMAL (HIGHEST ALONG MD EASTERN
SHORE). IF THIS GUIDANCE COMES TO FRUITION...MODERATE TO SEVER
COASTAL FLOODING IMPACTS ARE EXPECTED AT OCEAN CITY INLET, WITH
WIDESPREAD MODERATE COASTAL FLOODING EXPECTED ON WESTERN SHORE OF
CHES BAY SOUTH OF NEW PT COMFORT DURING THE THU MORNING HIGH TIDE.
SEE CFWAKQ FOR SITE SPECIFIC DETAILS.
UNFORTUNATELY, THE SLOW MOVEMENT OF THE SFC LOW WILL KEEP POSITIVE
TIDAL ANOMALIES THROUGH FRIDAY. AND WHILE THE TIDE CYCLE THURSDAY
NIGHT APPEARS TO BE CLOSER TO MINOR, THE HIGHER ASTRONOMICAL TIDE
FOR FRIDAY MORNING COULD APPROACH MODERATE CCOASTAL FLOODING
IMPACTS YET AGAIN. SUBSTANTIAL IMPROVEMENT IS EXPECTED LATER
FRIDAY AND ESPECIALLY ON SATURDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR MDZ024-025.
WIND ADVISORY UNTIL 10 AM EST THURSDAY FOR MDZ021>025.
NC...WIND ADVISORY UNTIL 9 AM EST THURSDAY FOR NCZ015>017-102.
VA...COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR VAZ084>086-091-
094>096-098>100.
WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ075>078-084>086-
091-094.
WIND ADVISORY UNTIL 9 AM EST THURSDAY FOR VAZ095-097-098.
WIND ADVISORY UNTIL 10 AM EST THURSDAY FOR VAZ099-100.
COASTAL FLOOD ADVISORY UNTIL 7 AM EST FRIDAY FOR VAZ077-078.
MARINE...STORM WARNING UNTIL 2 AM EST THURSDAY FOR ANZ652-654-656.
STORM WARNING UNTIL 5 AM EST THURSDAY FOR ANZ650.
GALE WARNING UNTIL 7 AM EST FRIDAY FOR ANZ658.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ635>637.
GALE WARNING UNTIL 7 AM EST THURSDAY FOR ANZ630>634-638.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB
SHORT TERM...ALB
LONG TERM...BMD
AVIATION...DAP/LSA
MARINE...BMD/MAM
TIDES/COASTAL FLOODING...MAM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
817 PM EST WED MAR 6 2013
.SYNOPSIS...
DEEPENING LOW PRESSURE WILL CONTINUE TO MOVE OUT TO SEA TONIGHT
THROUGH THURSDAY. HIGH PRESSURE SLOWLY BUILDS INTO THE AREA FROM
THURSDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
SFC LO PRES NOW JUST OFF THE ERN SHORE OF VA...AND WILL CONT TO
SLO DRIFT OFFSHR THROUGH THE OVRNGT. COLDER AIR RIGHT BEHIND THE
STM IS HAVING DIFFICULTY MOVING OVR THE ERN PORTION OF THE FA
RIGHT NOW...AND WILL RMN SLO TO DO SO INTO/THROUGH THE (ERY) EVE.
INLAND...COLDER AIR HAS MANAGED TO CHANGE PCPN TO SN FOR A WHILE
FOR MUCH OF CNTRL/WRN AND SRN PORTIONS OF FA. PCPN RATE HAS CONTD
TO DCRS THROUGH THE AFTN ON THE NW AND W SIDE OF THE STM AND W/
TEMPS IN THE (M/U)30S...RA HAS BEEN MIXED W/ THE WET SN. ACCUMS ARE
GENLY OVR...RMNG BLO 1 INCH FOR MANY LOCATIONS. ONE AREA OF CONTD
CONCERN IS OVR THE LWR MD ERN SHR TNGT...THOUGH THERE IS CONCERN
ABT ENOUGH COLD AIR TO BE BROUGHT INTO THE AREA TO CHANGE THE PCPN
OVR TO ACCUM SN.
HAVE LWRD WINTER WARNING TO ADVSRY...AND WILL LEAVE ADVSRY FOR THE
OTHER AREAS THROUGH THE EVE HRS (THROUGH OVRNGT ON THE LWR MD ERN
SHR...THOUGH LWRD ACCUMS TO 1-2 INCH).
ADDITIONALLY...NNW WNDS WILL RMN GUSTY TO 35 TO 50 MPH...ESP FM
I95 TO THE CST. WIND ADVSRY RMNS IN PLACE FOR ERN VA/LWR MD AND
CSTL NE NC.
PCPN WINDS DOWN LT EVE/OVRNGT...W/ LO TEMPS NR/SLGTLY BLO
FRZG...MAY HAVE SLUSH REFREEZE FM RIC N AND W. MOST LO TEMPS TNGT
FM THE U20S W TO M30S E.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
LO PRES CONTS TO MOVE OUT TO SEA THU THROUGH SAT. A SECOND S/W
DIVING SSE FM WRN NEW ENG/NY STATE ON FRI PSBLY RESULTING IN
BKN/OVC CLDNS (ESP E OF I 95) AND ISOLD/SCT PCPN. NNW WINDS WILL
RMN GUSTY AS WELL...ESP NR THE CST...THROUGH FRI. SFC HI PRES IS
SLO TO BUILD SWD INTO THE MDATLC RGN BY SAT...FINALLY RESULTING IN
DRY WX FOR ALL AREAS.
P/MCLDY TNGT...THEN PCLDY OR VRB CLDNS THU. PCLDY W/MCLDY E THU
NGT THROUGH FRI...THEN MSTLY SKC ON SAT. HI TEMPS RANGING THROUGH
THE 40S N AND CNTRL AREAS...TO L50S S THU/FRI...THEN FM THE U40S
TO M50S SAT. LO TEMPS IN THE U20S TO L30S THU/FRI NGTS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GOING WITH A COMBINATION OF THE 12Z GFS/ECMWF FOR THE EXTENDED
PERIOD...ESPLY WITH REGARD TO TIMING OF APPROACH AND PASSAGE OF COLD
FRONT MON NGT THRU TUE. UA RDG/LRG AREA OF SFC HI PRES WILL PROVIDE
DRY WX SAT NGT INTO MON MORNG. LO PRES AND ASSOC COLD FRONT WILL
THEN AFFECT THE REGION MON EVENG THRU TUE...WITH DECENT CHC FOR
SHOWERS. MILDER TEMPS EXPECTED SUN INTO TUE. DRY WX RETURNS FOR TUE
NGT THRU WED...AS HI PRES WILL GRADUALLY BLD IN FM THE NW. MIN TEMPS
WILL BE IN THE LWR TO MID 30S SUN MORNG...IN THE UPR 30S TO LWR 40S
MON MORNG...IN THE 40S TUE MORNG...AND IN THE MID 30S TO ARND 40 WED
MORNG. MAX TEMPS WILL BE IN THE MID 50S TO LWR 60S SUN...IN THE LWR
TO MID 60S MON...IN THE MID 50S TO LWR 60S TUE...AND IN THE MID TO
UPR 50S WED.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE HAS MOVED OFF THE VA/NC COAST AND STRONG WINDS ARE
GUSTING FROM THE N/NNW AT ALL TAF SITES. GUSTS TO 40-45 KT REMAIN
PSBL AT TIMES THROUGH THE OVERNIGHT HOURS...ESPECIALLY ALONG THE COAST.
RAIN AND SNOW WILL TAPER OFF TONIGHT. CIGS AND VSBYS WILL CONTINUE
TO BE IN AND OUT OF IFR CONDS WITH MAINLY IFR ON THE BACKSIDE OF
THE LOW. PCPN ENDS AND DRYING WILL ALLOW CIGS TO IMPROVE AFT 05Z.
VFR CONDS ARE EXPECTED TOWARD MORNING WITH WINDS GUSTING TO 25KT
IN THE AFTN.
THE LOW WILL CONTINUE TO SLOWLY PUSH OFFSHORE ALLOWING HIGH PRESSURE
TO BUILD IN FROM THE NW. FAIR WEATHER/VFR CONDITIONS WILL PREVAIL
INTO EARLY NEXT WEEK WITH GUSTY WINDS CONTINUING DUE TO THE STRONG
PRESSURE GRADIENT THAT WILL REMAIN OVER THE AREA.
&&
.MARINE...
UPDATE: HAVE HOISTED STORM WARNING FOR ATLANTIC COASTAL WATERS
NORTH OF VA/NC BORDER. HAVE BEEN HANDLING WITH SPECIAL MARINE
WARNINGS THUS FAR, BUT WITH HRRR SHOWING THIS SURGE LASTING A FEW
HOURS LONGER, FEEL A BIT MORE COMFORTABLE HOISTING STORM HEADLINE
THROUGH 2AM, WITH A PERIOD OF GALES LIKELY AFTER WINDS DIMINISH
SOME AFTER MIDNIGHT. WILL REASSESS GALES OVER RIVERS (EXPIRING AT
3Z IN THE NEXT HOUR) SHORTLY.
PREVIOUS DISCUSSION....
A STRENGTHENING SFC LOW PRESSURE WILL ROTATE
OVER THE MID ATLANTIC COAST THIS EVENING...THEN PUSH OUT TO SEA
OVERNIGHT. WIND DIRECTIONS ARE PRIMARILY N LATE THIS AFTN AND WILL
BECOME MORE NWLY AS THE EVENING PROGRESSES. A NRLY SURGE HAS BEGUN
OVER NRN CHES BAY AND WILL CONTINUE TO PUSH SWD THROUGH THE
EVENING. CURRENT FORECAST ALREADY HAS THIS TREND IN PLACE. FOR
COASTAL WATERS N OF CHINCOTEAGUE...A STORM WARNING HAS BEEN ISSUED
THROUGH EARLY THU MORNING AS THE NRLY SURGE COMMENCES LATE THIS
AFTN INTO THE EVENING AND GUSTS REACH 50-55 KT. IN ADDITION...GALE
WARNINGS HAVE BEEN ISSUED FOR THE RIVERS TO ACCOUNT FOR THE NRLY
SURGE AND FOR WHEN WINDS BECOME NWLY...WHICH IS A FAVORABLE
ORIENTATION FOR STRONG WINDS TO OCCUR. GALES ARE EXPECTED TO FALL
BELOW 34 KT AT VARIOUS TIMES TONIGHT AND THU MORNING...AND WILL BE
REPLACED BY SOLID SCA FLAGS AS DEEMED NECESSARY. SEAS ARE ANYWHERE
FROM 10-19 FEET N OF CAPE CHARLES AND 5-9 FT S OF CAPE CHARLES.
THEY SHOULD STAY ELEVATED THROUGH THU MORNING AND THEN FALL VERY
SLOWLY THROUGH THE REST OF THE WEEK.
AS THE SFC LOW PUSHES EAST OF LONGITUDE 70W LATE THU NIGHT INTO
FRI...THE PRESSURE GRADIENT REMAINS TIGHT AND A SECONDARY SHORTWAVE
FEATURE MOVES SE ACROSS THE WATERS. THIS FEATURE WILL BRING A
REINFORCING SHOT OF COLD AIR INTO THE REGION AND THE SUBSEQUENT CAA
WILL PRODUCE ANOTHER ROUND OF SOLID SCA CONDITIONS (POSSIBLY GALES
OVER COASTAL WATERS) THU NIGHT INTO FRI MORNING. WINDS THEN SHIFT TO
THE N FRI NIGHT AND HIGH PRESSURE BEGINS TO BUILD INTO THE AREA FROM
NW...BRINGING MORE QUIET CONDITIONS TO AREA WATERS THROUGH THE
WEEKEND.
&&
.TIDES/COASTAL FLOODING...
UPDATE...COASTAL FLOOD WARNING HAS BEEN UPDATED TO RUN THROUGH
EARLY FRIDAY OVER ALL COASTAL AREAS NORTH OF VA/NC BORDER, WITH
THE EXCEPTION OF LANCASTER/NORTHUMBERLAND COUNTIES, WHERE SLIGHTLY
LOWER WATER LEVELS NECESSITATES ONLY AN ADVISORY. TIDAL DEPARTURES
ON THE ORDER OF 2.5 TO 4 FT ABOVE NORMAL HAVE LED TO MODERATE
COASTAL FLOODING IMPACTS ALREADY OVER MUCH OF THIS AREA, WITH
ADDITIONAL ANOMALIES EXPECTED TONIGHT AND OVERNIGHT. MDL AND CBOFS
GUIDANCE HAVE BOTH UNDERESTIMATED THIS NORTHERLY SURGE THIS
EVENING, AND HAVE SIDED CLOSE TO/JUST ABV VIMS GUIDANCE FOR THIS
PACKAGE, AS IT APPEARS TO BE THE MOST ACCURATE IN DEPICTING TIDAL
LEVELS OCCURRING RIGHT NOW. THIS GUIDANCE INDICATING ANOTHER TIDE
CYCLE BETWEEN 2.5 TO 4 FT ABV NORMAL (HIGHEST ALONG MD EASTERN
SHORE). IF THIS GUIDANCE COMES TO FRUITION...MODERATE TO SEVER
COASTAL FLOODING IMPACTS ARE EXPECTED AT OCEAN CITY INLET, WITH
WIDESPREAD MODERATE COASTAL FLOODING EXPECTED ON WESTERN SHORE OF
CHES BAY SOUTH OF NEW PT COMFORT DURING THE THU MORNING HIGH TIDE.
SEE CFWAKQ FOR SITE SPECIFIC DETAILS.
UNFORTUNATELY, THE SLOW MOVEMENT OF THE SFC LOW WILL KEEP POSITIVE
TIDAL ANOMALIES THROUGH FRIDAY. AND WHILE THE TIDE CYCLE THURSDAY
NIGHT APPEARS TO BE CLOSER TO MINOR, THE HIGHER ASTRONOMICAL TIDE
FOR FRIDAY MORNING COULD APPROACH MODERATE CCOASTAL FLOODING
IMPACTS YET AGAIN. SUBSTANTIAL IMPROVEMENT IS EXPECTED LATER
FRIDAY AND ESPECIALLY ON SATURDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR MDZ024-025.
WIND ADVISORY UNTIL 10 AM EST THURSDAY FOR MDZ021>025.
NC...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ014-031-032.
WIND ADVISORY UNTIL 9 AM EST THURSDAY FOR NCZ015>017-102.
VA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ089-090-093-
096.
COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR VAZ084>086-091-
094>096-098>100.
WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ075>078-084>086-
091-094.
WIND ADVISORY UNTIL 9 AM EST THURSDAY FOR VAZ095-097-098.
WIND ADVISORY UNTIL 10 AM EST THURSDAY FOR VAZ099-100.
COASTAL FLOOD ADVISORY UNTIL 7 AM EST FRIDAY FOR VAZ077-078.
MARINE...STORM WARNING UNTIL 2 AM EST THURSDAY FOR ANZ652-654-656.
STORM WARNING UNTIL 4 AM EST THURSDAY FOR ANZ650.
GALE WARNING UNTIL 7 AM EST FRIDAY FOR ANZ658.
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ635>637.
GALE WARNING UNTIL 7 AM EST THURSDAY FOR ANZ630>634-638.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB
SHORT TERM...ALB
LONG TERM...BMD
AVIATION...DAP/LSA
MARINE...BMD/MAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 PM EST TUE MAR 5 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 407 PM EST TUE MAR 5 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE
DROPPING SE INTO THE MID MISSISSIPPI VALLEY. WAVE IS BEING FORCED SE
BY MID LEVEL HIGH OVER QUEBEC. AS A RESULT...SYSTEM SNOW HAS PAST BY
TO THE W AND S OF UPPER MI TODAY. SOME VERY LIGHT LES IS OCCURRING
IN E TO NE FLOW ACROSS LAKE SUPERIOR INTO THE KEWEENAW AND NCNTRL
UPPER MI AS TEMPS AT THE BASE OF A LOW 3KFT INVERSION ARE JUST
SUFFICIENT FOR LES AT -11C. UNDER DOWNSLOPING E TO NE LOW-LEVEL
WINDS...THE ERN FCST AREA HAS ENJOYED A SUNNY DAY TODAY.
VIGOROUS SHORTWAVE/MID LEVEL LOW OVER THE MID MISSISSIPPI VALLEY
WILL MOVE TO VCNTY OF NC BY WED MORNING AND WILL HAVE LITTLE IMPACT
ON WEATHER HERE. WHAT WILL BE A FACTOR IS A NRN STREAM SHORTWAVE
THAT WILL BE DRIFTING INTO THE UPPER LAKES LATE TONIGHT/WED...
BRINGING A DECENT AREA OF DEEP LAYER FORCING PER QVECTORS. THE
APPROACHING SHORTWAVE WILL HELP SHARPEN LOW-LEVEL CYCLONIC N TO NE
FLOW ACROSS LAKE SUPERIOR TONIGHT/WED MORNING BEFORE WINDS SHIFT NW
WED AS THE WAVE REACHES THE AREA. WHILE LOW-LEVEL THERMAL PROFILE
CHANGES VERY LITTLE...OVERWATER INSTABILITY IS MORE THAN SUFFICIENT
FOR LAKE ENHANCEMENT...AND THE FACT THAT SOME VERY LIGHT LES IS
ALREADY OCCURRING SUGGESTS THERE SHOULD BE A DECENT UPTICK IN LES
TONIGHT/WED MORNING. WITH ALL MODEL GUIDANCE SHOWING A SSE TO NNW
ORIENTED SFC TROF DEVELOPING ACROSS ROUGHLY CNTRL LAKE SUPERIOR...IT
WOULD APPEAR THAT NW AND NCNTRL UPPER MI SHOULD BE FAVORED FOR MORE
PERSISTENT SNOW. SNOW TO WATER RATIOS SHOULD BE ON THE LOW SIDE
10-15 TO 1...EXCEPT IN THE VCNTY/ALONG THE AFORENTIONED SFC TROF
WHERE DEEPER VERTICAL MOTION...THOUGH NOT STRONG...SHOULD INTERSECT
THE DGZ AND POSSIBLY BOOST RATIOS TOWARD 20 TO 1. AT THIS POINT...IT
APPEARS ACCUMULATIONS UPWARDS OF AROUND 3 INCHES ARE POSSIBLE OVER
NW/NCNTRL HIGHER TERRAIN TONIGHT/WED MORNING. ACCUMULATIONS SHOULD
BE A LITTLE LESS FARTHER W TOWARD KIWD. IT REALLY WON`T BE UNTIL
LATER WED MORNING/AFTN WHEN SFC TROF PASSES THAT SNOW REACHES THE NE
FCST AREA. AWAY FROM LAKE ENHANCEMENT...EXPECT SOME -SN/-SHSN TIED
TO SHORT PERIOD OF STRONGER FORCING ASSOCIATED WITH SHORTWAVE. -SHSN
WILL DIMINISH W TO E WED AFTN AND MAY END OVER THE W.
TEMPS TONIGHT ARE FAIRLY STRAIGHTFORWARD WITH CLOUD COVER LIMITING
TEMP FALL. ONE EXCEPTION IS THE ERN FCST AREA AS IT`S UNCERTAIN WHEN
CLOUDS WILL INCREASE SUFFICIENTLY TO SLOW/STOP TEMP FALL THERE
TONIGHT. GIVEN THAT IT`S SUNNY IN THAT AREA NOW...AND SATELLITE
IMAGERY SHOWS NO TREND TO CLOUD UP SOON...TEMPS COULD PLUMMET
QUICKLY THIS EVENING. FCST WILL SHOW MINS IN THE MID TEENS...BUT
IT`S QUITE POSSIBLE TEMPS COULD FALL WELL DOWN INTO THE SINGLE
DIGITS DURING THE EVENING IF IT REMAINS MOSTLY CLEAR. MID 20S TO LWR
30S SHOULD BE THE RULE WED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 407 PM EST TUE MAR 5 2013
LINGERING SURFACE TROUGH AND NORTHERN STREAM SHORTWAVE WILL BE
SLIDING EAST ACROSS EASTERN LAKE SUPERIOR ON WEDNESDAY EVENING WHILE
AN AREA OF HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES. WITH
900MB TEMPS STILL AROUND -12C AND ENOUGH LOW LEVEL MOISTURE BELOW
THE 3-4KFT INVERSION...SHOULD STILL SEE LOW CLOUDS ACROSS THE AREA
DURING THE EVENING IN THE NORTH-NORTHWEST WIND LOCATIONS. DURING THE
EVENING...WOULD EXPECT ISOLATED/SCATTERED SNOW SHOWERS IN THOSE SAME
WIND FAVORED LOCATIONS. WITH A LITTLE DEEPER MOISTURE OVER THE
EASTERN LOCATIONS...MAINLY FROM MUNISING EASTWARD...WOULD EXPECT
ISOLATED LIGHT SNOW SHOWERS TO CONTINUE THROUGH THE NIGHT. OVER THE
WEST...THE INFLUENCE OF THE HIGH WILL ALLOW THE FLOW TO BECOME
ANTI-CYCLONIC THROUGH THE NIGHT AND INCREASE THE DRY AIR OVER THE
WESTERN LAKE...SLOWLY DECREASING THE CLOUDS IN THAT AREA. THIS
DECREASE IN CLOUDS LEADS TO UNCERTAINTY IN THE LOWS OVER THE WESTERN
CWA. WITH LIGHT WINDS AND PWATS AROUND 50 PERCENT OF
NORMAL...LOCATIONS THAT DO CLEAR OUT WILL LIKELY FALL INTO THE
SINGLE DIGITS AND WOULDN/T BE SURPRISED TO SEE A FEW BELOW ZERO
READINGS IN THE COLD SPOTS OF EASTERN GOGEBIC AND IRON COUNTY.
THE HIGH WILL CONTINUE TO MOVE OVER THE AREA ON THURSDAY...CAUSING
WINDS TO BECOME MORE VARIABLE. WITH THE STRENGTHENING SUBSIDENCE
INVERSION...THE QUESTION FOR THURSDAY WILL BE WHERE THE CLOUDS WILL
BE LOCATED AND IF/WHEN THEY WILL MIX OUT. WILL HOLD ONTO THE CLOUDS
THE LONGEST OVER THE EAST WHERE THE NORTHWEST WINDS WILL BE MOST
PERSISTENT. ELSEWHERE...WENT WITH MORE OF A PARTLY CLOUDY TO MOSTLY
SUNNY SKY AS DIURNAL MIXING WILL LIKELY EAT AWAY AT THE CLOUDS.
UPPER RIDGE BUILDS OVER THE AREA ON THURSDAY NIGHT INTO
FRIDAY...WHICH WILL KEEP THE AREA DRY AND ONLY PRODUCE SOME
MID-HIGH CLOUDS STREAMING ACROSS THE AREA. BY FRIDAY NIGHT...AN
UPPER TROUGH WILL BE SITTING OVER THE SOUTHWEST CONUS AND A
NORTHERN STREAM TROUGH WILL BE MOVING THROUGH
MANITOBA/SASKATCHEWAN. THE QUESTION BECOMES WHETHER THESE TWO
TROUGHS WILL SEPARATE OR STAY TOGETHER...WHICH THEN INFLUENCES THE
FORECAST INTO THE FIRST PART OF NEXT WEEK. THE LATEST TRENDS IN THE
12Z MODEL RUNS IS TO KEEP THE WAVES PHASED ENOUGH THROUGH THE
WEEKEND DUE TO A STRONGER NORTHERN STREAM WAVE. THIS IN TURN LEADS
TO STRONGER FORCING WITH THE SURFACE TROUGH MOVING THROUGH SATURDAY
INTO SATURDAY EVENING. WITH THIS STRONGER WAVE AND INCREASED
SOUTHERLY FLOW AHEAD OF THE SYSTEM...MODELS HAVE TRENDED UP WITH
THE QPF...ESPECIALLY OVER THE WESTERN HALF OF THE CWA. HAVE TRENDED
POPS UP FOR THIS PERIOD AND WITH SOME OF THE QPF AMOUNTS SHOWN ON
THE 12Z RUNS...COULD SEE NEAR ADVISORY SNOWFALL FOR SOME LOCATIONS
OVER WESTERN UPPER MICHIGAN. WON/T MENTION THIS IN THE HWO AT THIS
POINT WITH THE WAY THE MODELS HAVE BEEN VARYING...BUT WILL BE
SOMETHING TO WATCH. FINALLY...LOOKING AT MODEL SOUNDINGS...THEY TRY
TO NOSE TEMPS ABOVE 0C AROUND 850MB OVER THE SOUTH CENTRAL WHICH
COULD LEAD TO SOME MELTING ALONG THE ISOTHERMAL LAYER TO THE
SURFACE. THUS...ADDED A MIX OF RAIN/SNOW TO THAT AREA.
HIGH PRESSURE WILL LIKELY BUILD INTO THE UPPER GREAT LAKES FOR
SUNDAY AND THE FIRST PART OF MONDAY...BEFORE THE NEARLY
CLOSED SOUTHERN STREAM TROUGH DRIFTS OUT OF THE SOUTHWEST CONUS.
WHILE THIS SYSTEM WAS LOOKING LIKE IT WAS GOING TO MOVE TOWARDS THE
UPPER GREAT LAKES ON THE 12Z RUNS YESTERDAY...THE LATEST TRENDS
HAVE IT MOVING MORE THROUGH THE OHIO RIVER VALLEY. THEREFORE...HAVE
TRENDED POPS DOWN FOR THE MONDAY PERIOD AND IF THE TREND CONTINUES
THEY MAY NEED TO BE REMOVED COMPLETELY.
AS FOR TEMPERATURES DURING THE LONG TERM PERIOD...IT LOOKS TO BE
FAIRLY NORMAL WITH A FEW DAYS OF SLIGHTLY ABOVE NORMAL HIGHS
THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1240 PM EST TUE MAR 5 2013
WITH A DISTURBANCE ARRIVING OVER THE UPPER LAKES LATE TONIGHT/WED
MORNING...-SHSN WILL INCREASE IN COVERAGE AND INTENSITY DURING THIS
FCST PERIOD. AT KIWD...EXPECT MVFR CONDITIONS THIS AFTN WITH -SHSN
DEVELOPING. CONDITIONS SHOULD SETTLE TO IFR TONIGHT UNDER FAVORABLE
UPSLOPE FLOW. AT KCMX...CONDITIONS SHOULD VARY BTWN MVFR/IFR THIS
AFTN BEFORE FALLING TO PREVAILING IFR TONIGHT. AT KSAW...MVFR
CONDITIONS THIS AFTN WILL FALL TO IFR THIS EVENING AS -SHSN DEVELOP.
FAVORABLE CONVERGENT UPSLOPE FLOW OVERNIGHT WILL PROBABLY RESULT IN
CIGS FALLING TO LIFR. IMPROVEMENT SHOULD OCCUR AT ALL SITES LATE WED
MORNING OR AFTN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST TUE MAR 5 2013
NE TO N WINDS OF 15-25KT WILL BE THE RULE ACROSS LAKE SUPERIOR
TONIGHT...THOUGH 20-30KT WINDS WILL LINGER OVER THE WRN PORTION OF
THE LAKE INTO THE EVENING HRS BEFORE PRES GRADIENT BEGINS TO RELAX.
WINDS WILL FALL OFF TO UNDER 20KT OVER WRN LAKE SUPERIOR WED. OVER
ERN LAKE SUPERIOR...TIGHTER PRES GRADIENT WILL ALLOW 15-25KT WINDS
TO PERSIST INTO EARLY THU MORNING. HIGH PRES RIDGE PASSING OVER THE
AREA WILL THEN LEAD TO WINDS UNDER 20KT ACROSS THE LAKE THU/FRI.
ALTHOUGH A LOW PRES TROF WILL PASS ACROSS LAKE SUPERIOR LATER
SAT/EARLY SUN...PRES GRADIENT REMAINS WEAK...KEEPING WINDS MOSTLY
UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1241 PM EST TUE MAR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST TUE MAR 5 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW PRES
TROF OVER THE DAKOTAS DEEPENING INTO THE MID MS VALLEY AND CENTRAL
PLAINS WITH A DOWNSTREAM RIDGE OVER THE UPR GREAT LAKES. AT THE
SFC...A RIDGE EXTENDED FROM NRN MANITOBA AND NW ONTARIO INTO ERN
UPPER MI ALLOWING FOR ENE WINDS AND MAINLY CLEAR SKIES OVER THE ERN
HALF OF UPPER MI EARLY THIS MORNING. Q-VECT CONV AND ISENTROPIC
ASCENT AHEAD OF THE SFC LOW OVER ERN DAKOTAS INTO MID MS VALLEY HAS
RESULTED IN MID CLOUDS SPREADING INTO THE WRN HALF OF THE FCST AREA.
MODELS CONSISTENT IN DEVELOPING MID-LVL CLOSED LOW OVER THE LOWER
MIDWEST/MID MS VALLEY TODAY WITH DEEPENING TROF AND THEN TRACKING
THIS SYSTEM EAST THROUGH THE OHIO VALLEY REACHING THE MID-ATLANTIC
COAST BY WED MORNING. AS NE FLOW STRENGTHENS AND BECOMES MORE
CYCLONIC ON THE BACKSIDE OF THIS SYSTEM...CHANCES OF LAKE
ENHANCED SNOWFALL SHOULD INCREASE ESPECIALLY LATE TODAY INTO
WED MORNING FOR WEST AND NORTH CENTRAL PORTIONS OF THE FCST AREA
FAVORED BY N-NE FLOW.
MODEL SOUNDINGS SHOW INCREASING MOISTURE ESPECIALLY FM 925-800 MB
BEING PULLED BACK ACROSS LAKE SUPERIOR WITH STRENGTHENING CYCLONIC
NE FLOW LATER THIS AFTERNOON INTO TONIGHT...INCREASING THE POTENTIAL
FOR LAKE ENHANCED SNOWFALL OVER WEST AND NORTH CENTRAL AREAS. WITH
TEMPS AT 900 MB INVERSION HEIGHT (NEAR 3K FT) ONLY AROUND
-12C...INSTABILITY AND SLR VALUES WILL BE MARGINAL FOR SIGNFICANT
SNOWFALL. HOWEVER...UPSLOPE FLOW INTO THE HIGHER TERRAIN COULD BOOST
LIFT ENOUGH TO SUPPORT -SHSN THIS AFTERNOON WITH ACCUMULATIONS LESS
THAN A HALF INCH. FOR THIS REASON WILL MAINTAIN HIGH CHC TO LIKELY
POPS OVER HIGHER TERRAIN OF WRN MQT COUNTY LATER THIS AFTERNOON.
BETTER CHANCES OF LAKE ENHANCED SNOW WILL BE TONIGHT AS MOISTURE
PROFILE CONTINUES TO DEEPEN AND AREA OF MODERATE 850-500 MB Q-VECT
CONV SPREADS WEST TO EAST ACROSS THE FCST AREA. INCREASING LOW-LVL
CONVERGENCE IN N-NE FLOW WILL ALSO PROVIDE ADDED FOCUS FOR LAKE
ENHANCED SNOW...ESPECIALLY OVER THE HIGHER TERRAIN AREAS OF WRN MQT
COUNTY. HAVE BUMPED UP POPS TO CATEGORICAL OR GREATER THAN 80 PCT
OVER MUCH OF THE WEST AND NORTH CENTRAL FCST AREA TONIGHT. WITH SLR
VALUES OF 12-14/1 AND MODEL AVG QPF APPROACHING .15 INCH OVER
FAVORED UPSLOPE...WOULD NOT BE SURPRISED TO SEE ACCUMS EXCEED TWO
INCHES OVER SOME LOCATIONS OF WRN MQT COUNTY. MOST OTHER AREAS OF
THE WEST AND NORTH CENTRAL CWA WILL SEE SNOW ACCUMS CLOSER TO AN
INCH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 516 AM EST TUE MAR 5 2013
WE START THE LONG TERM PERIOD 12Z WED LOOKING AT A 500MB TROUGH PUSHING
INTO WRN UPPER MI. HEIGHT FALLS AHEAD OF THE TROUGH WILL LEAD TO
SYNOPTIC SNOW OVER WRN UPPER MI BY 12Z WED...MOVING E OF THE CWA BY
06Z THU AS THE TROUGH CLOSES OFF INTO A LOW WHILE MOVING FROM NRN
LAKE SUPERIOR 00Z THU TO E OF LAKE SUPERIOR BY 12Z THU. IN ADDITION
TO THE SYNOPTIC SNOW...INVERSION TOP TEMPS AROUND 900MB WILL BE COLD
ENOUGH TO SUPPORT LAKE ENHANCEMENT/UPSLOPE SNOW WITH N-NW LOW LEVEL
WINDS. ESPECIALLY FAVORED WILL BE THE HIGHER TERRAIN OF N CENTRAL
AND WRN UPPER MI. EVEN SO...BEST LIFT WILL BE ABOVE THE DGZ...AND
TEMPS WILL STILL BE ON THE LOW END OF FAVORABLE...SO SNOW TO LIQUID
RATIOS WILL NOT BE AS HIGH AS THE COULD BE /BELOW 15 TO 1/ WHICH
WILL HELP LIMITED SNOWFALL AMOUNTS. LAKE ENHANCED SNOW WILL WEAKEN
QUICKLY AFTER SYNOPTIC SNOW MOVES E...BUT SOME LES IN COLDER TEMPS
BEHIND THE TROUGH WILL REMAIN POSSIBLE INTO THU WHEN WINDS BECOME
LIGHT AND BEGIN TO TURN SLY AFTER THE PASSAGE OF A SFC RIDGE. THINK
HIGHEST PRECIP AMOUNTS ON WED OVER THE HIGHER TERRAIN WILL BE AROUND
1 INCH.
UNCERTAINTY STARTS TO INCREASE ON FRI AS MODELS ARE HAVING
DIFFICULTY HANDLING SHORTWAVE ENERGY TOPPING THE UPPER RIDGE
OVERHEAD. MODELS DISAGREE WITH ONE ANOTHER AND FROM ONE RUN TO THE
NEXT...SO CONFIDENCE IS LOW AS TO THE POSITION OF ANY PRECIP FROM
THE SHORTWAVE ENERGY. IT DOES APPEAR THAT MOISTURE WILL BE LIMITED
ENOUGH TO KEEP PRECIP FROM BEING WIDESPREAD...BUT THAT IS AS MUCH
DETAIL AS CAN BE AFFORDED AT THIS POINT. USED A CONSENSUS OF
GUIDANCE FOR THIS PERIOD GIVEN THE LIMITED CONFIDENCE IN ANY ONE MODEL
EVEN MORE UNCERTAINTY AND LOWER CONFIDENCE FOR NEXT WEEKEND AND
EARLY NEXT WEEK AS MODELS STRUGGLE TO CONSISTENTLY HANDLE THE
PHASING OF THE NRN AND SRN STREAM SYSTEMS OVER NAMERICA. CONTINUED TO
USE A CONSENSUS OF GUIDANCE.
IN GENERAL...TEMPS SHOULD WARM INTO THE WEEKEND TO THE MID TO UPPER
30S BY SAT...WITH MUCH INCREASED UNCERTAINTY INTO MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1240 PM EST TUE MAR 5 2013
WITH A DISTURBANCE ARRIVING OVER THE UPPER LAKES LATE TONIGHT/WED
MORNING...-SHSN WILL INCREASE IN COVERAGE AND INTENSITY DURING THIS
FCST PERIOD. AT KIWD...EXPECT MVFR CONDITIONS THIS AFTN WITH -SHSN
DEVELOPING. CONDITIONS SHOULD SETTLE TO IFR TONIGHT UNDER FAVORABLE
UPSLOPE FLOW. AT KCMX...CONDITIONS SHOULD VARY BTWN MVFR/IFR THIS
AFTN BEFORE FALLING TO PREVAILING IFR TONIGHT. AT KSAW...MVFR
CONDITIONS THIS AFTN WILL FALL TO IFR THIS EVENING AS -SHSN DEVELOP.
FAVORABLE CONVERGENT UPSLOPE FLOW OVERNIGHT WILL PROBABLY RESULT IN
CIGS FALLING TO LIFR. IMPROVEMENT SHOULD OCCUR AT ALL SITES LATE WED
MORNING OR AFTN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 516 AM EST TUE MAR 5 2013
LOW PRESSURE CONSOLIDATING AND DEEPENING OVER THE TENNESSEE VALLEY
REGION WILL SUSTAIN NE WINDS TO 30 KTS OVER THE WRN THIRD OF LAKE
SUPERIOR TODAY WHERE LOW LEVEL CONV IS STRONGEST. NORTH WINDS TO 25
KTS CONTINUE THROUGH TONIGHT. DUE TO THE GUSTY WINDS AND COLDER
TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT TIMES THROUGH
TONIGHT. WINDS DIMINISH TO LESS THAN 20 KTS LATER WEDNESDAY INTO
FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
731 AM EST TUE MAR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST TUE MAR 5 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW PRES
TROF OVER THE DAKOTAS DEEPENING INTO THE MID MS VALLEY AND CENTRAL
PLAINS WITH A DOWNSTREAM RIDGE OVER THE UPR GREAT LAKES. AT THE
SFC...A RIDGE EXTENDED FROM NRN MANITOBA AND NW ONTARIO INTO ERN
UPPER MI ALLOWING FOR ENE WINDS AND MAINLY CLEAR SKIES OVER THE ERN
HALF OF UPPER MI EARLY THIS MORNING. Q-VECT CONV AND ISENTROPIC
ASCENT AHEAD OF THE SFC LOW OVER ERN DAKOTAS INTO MID MS VALLEY HAS
RESULTED IN MID CLOUDS SPREADING INTO THE WRN HALF OF THE FCST AREA.
MODELS CONSISTENT IN DEVELOPING MID-LVL CLOSED LOW OVER THE LOWER
MIDWEST/MID MS VALLEY TODAY WITH DEEPENING TROF AND THEN TRACKING
THIS SYSTEM EAST THROUGH THE OHIO VALLEY REACHING THE MID-ATLANTIC
COAST BY WED MORNING. AS NE FLOW STRENGTHENS AND BECOMES MORE
CYCLONIC ON THE BACKSIDE OF THIS SYSTEM...CHANCES OF LAKE
ENHANCED SNOWFALL SHOULD INCREASE ESPECIALLY LATE TODAY INTO
WED MORNING FOR WEST AND NORTH CENTRAL PORTIONS OF THE FCST AREA
FAVORED BY N-NE FLOW.
MODEL SOUNDINGS SHOW INCREASING MOISTURE ESPECIALLY FM 925-800 MB
BEING PULLED BACK ACROSS LAKE SUPERIOR WITH STRENGTHENING CYCLONIC
NE FLOW LATER THIS AFTERNOON INTO TONIGHT...INCREASING THE POTENTIAL
FOR LAKE ENHANCED SNOWFALL OVER WEST AND NORTH CENTRAL AREAS. WITH
TEMPS AT 900 MB INVERSION HEIGHT (NEAR 3K FT) ONLY AROUND
-12C...INSTABILITY AND SLR VALUES WILL BE MARGINAL FOR SIGNFICANT
SNOWFALL. HOWEVER...UPSLOPE FLOW INTO THE HIGHER TERRAIN COULD BOOST
LIFT ENOUGH TO SUPPORT -SHSN THIS AFTERNOON WITH ACCUMULATIONS LESS
THAN A HALF INCH. FOR THIS REASON WILL MAINTAIN HIGH CHC TO LIKELY
POPS OVER HIGHER TERRAIN OF WRN MQT COUNTY LATER THIS AFTERNOON.
BETTER CHANCES OF LAKE ENHANCED SNOW WILL BE TONIGHT AS MOISTURE
PROFILE CONTINUES TO DEEPEN AND AREA OF MODERATE 850-500 MB Q-VECT
CONV SPREADS WEST TO EAST ACROSS THE FCST AREA. INCREASING LOW-LVL
CONVERGENCE IN N-NE FLOW WILL ALSO PROVIDE ADDED FOCUS FOR LAKE
ENHANCED SNOW...ESPECIALLY OVER THE HIGHER TERRAIN AREAS OF WRN MQT
COUNTY. HAVE BUMPED UP POPS TO CATEGORICAL OR GREATER THAN 80 PCT
OVER MUCH OF THE WEST AND NORTH CENTRAL FCST AREA TONIGHT. WITH SLR
VALUES OF 12-14/1 AND MODEL AVG QPF APPROACHING .15 INCH OVER
FAVORED UPSLOPE...WOULD NOT BE SURPRISED TO SEE ACCUMS EXCEED TWO
INCHES OVER SOME LOCATIONS OF WRN MQT COUNTY. MOST OTHER AREAS OF
THE WEST AND NORTH CENTRAL CWA WILL SEE SNOW ACCUMS CLOSER TO AN
INCH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 516 AM EST TUE MAR 5 2013
WE START THE LONG TERM PERIOD 12Z WED LOOKING AT A 500MB TROUGH PUSHING
INTO WRN UPPER MI. HEIGHT FALLS AHEAD OF THE TROUGH WILL LEAD TO
SYNOPTIC SNOW OVER WRN UPPER MI BY 12Z WED...MOVING E OF THE CWA BY
06Z THU AS THE TROUGH CLOSES OFF INTO A LOW WHILE MOVING FROM NRN
LAKE SUPERIOR 00Z THU TO E OF LAKE SUPERIOR BY 12Z THU. IN ADDITION
TO THE SYNOPTIC SNOW...INVERSION TOP TEMPS AROUND 900MB WILL BE COLD
ENOUGH TO SUPPORT LAKE ENHANCEMENT/UPSLOPE SNOW WITH N-NW LOW LEVEL
WINDS. ESPECIALLY FAVORED WILL BE THE HIGHER TERRAIN OF N CENTRAL
AND WRN UPPER MI. EVEN SO...BEST LIFT WILL BE ABOVE THE DGZ...AND
TEMPS WILL STILL BE ON THE LOW END OF FAVORABLE...SO SNOW TO LIQUID
RATIOS WILL NOT BE AS HIGH AS THE COULD BE /BELOW 15 TO 1/ WHICH
WILL HELP LIMITED SNOWFALL AMOUNTS. LAKE ENHANCED SNOW WILL WEAKEN
QUICKLY AFTER SYNOPTIC SNOW MOVES E...BUT SOME LES IN COLDER TEMPS
BEHIND THE TROUGH WILL REMAIN POSSIBLE INTO THU WHEN WINDS BECOME
LIGHT AND BEGIN TO TURN SLY AFTER THE PASSAGE OF A SFC RIDGE. THINK
HIGHEST PRECIP AMOUNTS ON WED OVER THE HIGHER TERRAIN WILL BE AROUND
1 INCH.
UNCERTAINTY STARTS TO INCREASE ON FRI AS MODELS ARE HAVING
DIFFICULTY HANDLING SHORTWAVE ENERGY TOPPING THE UPPER RIDGE
OVERHEAD. MODELS DISAGREE WITH ONE ANOTHER AND FROM ONE RUN TO THE
NEXT...SO CONFIDENCE IS LOW AS TO THE POSITION OF ANY PRECIP FROM
THE SHORTWAVE ENERGY. IT DOES APPEAR THAT MOISTURE WILL BE LIMITED
ENOUGH TO KEEP PRECIP FROM BEING WIDESPREAD...BUT THAT IS AS MUCH
DETAIL AS CAN BE AFFORDED AT THIS POINT. USED A CONSENSUS OF
GUIDANCE FOR THIS PERIOD GIVEN THE LIMITED CONFIDENCE IN ANY ONE MODEL
EVEN MORE UNCERTAINTY AND LOWER CONFIDENCE FOR NEXT WEEKEND AND
EARLY NEXT WEEK AS MODELS STRUGGLE TO CONSISTENTLY HANDLE THE
PHASING OF THE NRN AND SRN STREAM SYSTEMS OVER NAMERICA. CONTINUED TO
USE A CONSENSUS OF GUIDANCE.
IN GENERAL...TEMPS SHOULD WARM INTO THE WEEKEND TO THE MID TO UPPER
30S BY SAT...WITH MUCH INCREASED UNCERTAINTY INTO MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 644 AM EST TUE MAR 5 2013
LOW PRESSURE DEVELOPING OVER THE MID MISSISSIPPI AND OHIO VALLEYS
TODAY WILL PULL DEEPER MOISTURE OVER UPPER MICHIGAN IN A NE
FLOW TODAY INTO TONIGHT. AS A RESULT...EXPECT SNOW SHOWERS TO BEGIN
LATE THIS MORNING/EARLY AFTERNOON AT ALL THREE TAF SITES WITH SNOW
SHOWERS INTENSIFYING SOME TONIGHT. LOW END MVFR CONDITIONS WILL BE
THE RULE THIS AFTERNOON LOWERING TO IFR TONIGHT AND PERHAPS LIFR AT
KSAW LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 516 AM EST TUE MAR 5 2013
LOW PRESSURE CONSOLIDATING AND DEEPENING OVER THE TENNESSEE VALLEY
REGION WILL SUSTAIN NE WINDS TO 30 KTS OVER THE WRN THIRD OF LAKE
SUPERIOR TODAY WHERE LOW LEVEL CONV IS STRONGEST. NORTH WINDS TO 25
KTS CONTINUE THROUGH TONIGHT. DUE TO THE GUSTY WINDS AND COLDER
TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT TIMES THROUGH
TONIGHT. WINDS DIMINISH TO LESS THAN 20 KTS LATER WEDNESDAY INTO
FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EST TUE MAR 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST TUE MAR 5 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW PRES
TROF OVER THE DAKOTAS DEEPENING INTO THE MID MS VALLEY AND CENTRAL
PLAINS WITH A DOWNSTREAM RIDGE OVER THE UPR GREAT LAKES. AT THE
SFC...A RIDGE EXTENDED FROM NRN MANITOBA AND NW ONTARIO INTO ERN
UPPER MI ALLOWING FOR ENE WINDS AND MAINLY CLEAR SKIES OVER THE ERN
HALF OF UPPER MI EARLY THIS MORNING. Q-VECT CONV AND ISENTROPIC
ASCENT AHEAD OF THE SFC LOW OVER ERN DAKOTAS INTO MID MS VALLEY HAS
RESULTED IN MID CLOUDS SPREADING INTO THE WRN HALF OF THE FCST AREA.
MODELS CONSISTENT IN DEVELOPING MID-LVL CLOSED LOW OVER THE LOWER
MIDWEST/MID MS VALLEY TODAY WITH DEEPENING TROF AND THEN TRACKING
THIS SYSTEM EAST THROUGH THE OHIO VALLEY REACHING THE MID-ATLANTIC
COAST BY WED MORNING. AS NE FLOW STRENGTHENS AND BECOMES MORE
CYCLONIC ON THE BACKSIDE OF THIS SYSTEM...CHANCES OF LAKE
ENHANCED SNOWFALL SHOULD INCREASE ESPECIALLY LATE TODAY INTO
WED MORNING FOR WEST AND NORTH CENTRAL PORTIONS OF THE FCST AREA
FAVORED BY N-NE FLOW.
MODEL SOUNDINGS SHOW INCREASING MOISTURE ESPECIALLY FM 925-800 MB
BEING PULLED BACK ACROSS LAKE SUPERIOR WITH STRENGTHENING CYCLONIC
NE FLOW LATER THIS AFTERNOON INTO TONIGHT...INCREASING THE POTENTIAL
FOR LAKE ENHANCED SNOWFALL OVER WEST AND NORTH CENTRAL AREAS. WITH
TEMPS AT 900 MB INVERSION HEIGHT (NEAR 3K FT) ONLY AROUND
-12C...INSTABILITY AND SLR VALUES WILL BE MARGINAL FOR SIGNFICANT
SNOWFALL. HOWEVER...UPSLOPE FLOW INTO THE HIGHER TERRAIN COULD BOOST
LIFT ENOUGH TO SUPPORT -SHSN THIS AFTERNOON WITH ACCUMULATIONS LESS
THAN A HALF INCH. FOR THIS REASON WILL MAINTAIN HIGH CHC TO LIKELY
POPS OVER HIGHER TERRAIN OF WRN MQT COUNTY LATER THIS AFTERNOON.
BETTER CHANCES OF LAKE ENHANCED SNOW WILL BE TONIGHT AS MOISTURE
PROFILE CONTINUES TO DEEPEN AND AREA OF MODERATE 850-500 MB Q-VECT
CONV SPREADS WEST TO EAST ACROSS THE FCST AREA. INCREASING LOW-LVL
CONVERGENCE IN N-NE FLOW WILL ALSO PROVIDE ADDED FOCUS FOR LAKE
ENHANCED SNOW...ESPECIALLY OVER THE HIGHER TERRAIN AREAS OF WRN MQT
COUNTY. HAVE BUMPED UP POPS TO CATEGORICAL OR GREATER THAN 80 PCT
OVER MUCH OF THE WEST AND NORTH CENTRAL FCST AREA TONIGHT. WITH SLR
VALUES OF 12-14/1 AND MODEL AVG QPF APPROACHING .15 INCH OVER
FAVORED UPSLOPE...WOULD NOT BE SURPRISED TO SEE ACCUMS EXCEED TWO
INCHES OVER SOME LOCATIONS OF WRN MQT COUNTY. MOST OTHER AREAS OF
THE WEST AND NORTH CENTRAL CWA WILL SEE SNOW ACCUMS CLOSER TO AN
INCH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 516 AM EST TUE MAR 5 2013
WE START THE LONG TERM PERIOD 12Z WED LOOKING AT A 500MB TROUGH PUSHING
INTO WRN UPPER MI. HEIGHT FALLS AHEAD OF THE TROUGH WILL LEAD TO
SYNOPTIC SNOW OVER WRN UPPER MI BY 12Z WED...MOVING E OF THE CWA BY
06Z THU AS THE TROUGH CLOSES OFF INTO A LOW WHILE MOVING FROM NRN
LAKE SUPERIOR 00Z THU TO E OF LAKE SUPERIOR BY 12Z THU. IN ADDITION
TO THE SYNOPTIC SNOW...INVERSION TOP TEMPS AROUND 900MB WILL BE COLD
ENOUGH TO SUPPORT LAKE ENHANCEMENT/UPSLOPE SNOW WITH N-NW LOW LEVEL
WINDS. ESPECIALLY FAVORED WILL BE THE HIGHER TERRAIN OF N CENTRAL
AND WRN UPPER MI. EVEN SO...BEST LIFT WILL BE ABOVE THE DGZ...AND
TEMPS WILL STILL BE ON THE LOW END OF FAVORABLE...SO SNOW TO LIQUID
RATIOS WILL NOT BE AS HIGH AS THE COULD BE /BELOW 15 TO 1/ WHICH
WILL HELP LIMITED SNOWFALL AMOUNTS. LAKE ENHANCED SNOW WILL WEAKEN
QUICKLY AFTER SYNOPTIC SNOW MOVES E...BUT SOME LES IN COLDER TEMPS
BEHIND THE TROUGH WILL REMAIN POSSIBLE INTO THU WHEN WINDS BECOME
LIGHT AND BEGIN TO TURN SLY AFTER THE PASSAGE OF A SFC RIDGE. THINK
HIGHEST PRECIP AMOUNTS ON WED OVER THE HIGHER TERRAIN WILL BE AROUND
1 INCH.
UNCERTAINTY STARTS TO INCREASE ON FRI AS MODELS ARE HAVING
DIFFICULTY HANDLING SHORTWAVE ENERGY TOPPING THE UPPER RIDGE
OVERHEAD. MODELS DISAGREE WITH ONE ANOTHER AND FROM ONE RUN TO THE
NEXT...SO CONFIDENCE IS LOW AS TO THE POSITION OF ANY PRECIP FROM
THE SHORTWAVE ENERGY. IT DOES APPEAR THAT MOISTURE WILL BE LIMITED
ENOUGH TO KEEP PRECIP FROM BEING WIDESPREAD...BUT THAT IS AS MUCH
DETAIL AS CAN BE AFFORDED AT THIS POINT. USED A CONSENSUS OF
GUIDANCE FOR THIS PERIOD GIVEN THE LIMITED CONFIDENCE IN ANY ONE MODEL
EVEN MORE UNCERTAINTY AND LOWER CONFIDENCE FOR NEXT WEEKEND AND
EARLY NEXT WEEK AS MODELS STRUGGLE TO CONSISTENTLY HANDLE THE
PHASING OF THE NRN AND SRN STREAM SYSTEMS OVER NAMERICA. CONTINUED TO
USE A CONSENSUS OF GUIDANCE.
IN GENERAL...TEMPS SHOULD WARM INTO THE WEEKEND TO THE MID TO UPPER
30S BY SAT...WITH MUCH INCREASED UNCERTAINTY INTO MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1217 AM EST TUE MAR 5 2013
EXPECT SNOW SHOWERS TO BEGIN LATE TONIGHT AT ALL THREE TAF SITES.
LOW PRESSURE WILL MOVE FROM THE NORTHERN PLAINS INTO THE OHIO VALLEY
OVERNIGHT AND TUESDAY. THIS WILL BRING SOME HIGH-MID LEVEL CLOUDS TO
THE AREA OVERNIGHT...AND LIMITED SUPPORT FOR SNOW AT IWD TONIGHT.
OTHERWISE...THIS SYSTEM WILL ALLOW SURFACE WINDS TO REMAIN EAST TO
NORTHEASTERLY INTO TOMORROW. AS A RESULT...LAKE EFFECT SNOW SHOWERS
WILL DEVELOP LATE TONIGHT AND LAST THROUGH TUESDAY AT ALL THREE
SITES. OVERALL...CONDITIONS SHOULD BE VFR THROUGH THE EARLY EVENING
TONIGHT...THEN DETERIORATE TO LOW END MVFR TOWARDS MORNING. LOW END
MVFR WILL BE THE RULE THROUGH THE REMAINDER OF THE DAY
TUESDAY...ESPECIALLY TOWARDS THE EVENING HOURS. SOME OF THE MODEL
GUIDANCE SUGGESTS IFR CONDITIONS DEVELOPING AFTER 3Z...HOWEVER
CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF AT THIS TIME.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 516 AM EST TUE MAR 5 2013
LOW PRESSURE CONSOLIDATING AND DEEPENING OVER THE TENNESSEE VALLEY
REGION WILL SUSTAIN NE WINDS TO 30 KTS OVER THE WRN THIRD OF LAKE
SUPERIOR TODAY WHERE LOW LEVEL CONV IS STRONGEST. NORTH WINDS TO 25
KTS CONTINUE THROUGH TONIGHT. DUE TO THE GUSTY WINDS AND COLDER
TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT TIMES THROUGH
TONIGHT. WINDS DIMINISH TO LESS THAN 20 KTS LATER WEDNESDAY INTO
FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...MCD
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1217 AM EST TUE MAR 5 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 356 PM EST MON MAR 4 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER THE
WRN DAKOTAS AND A DOWNSTREAM RIDGE OVER THE WRN GREAT LAKES. AT THE
SFC...A RIDGE EXTENDED FROM NRN MANITOBA AND NW ONTARIO INTO UPPER
MI BRINGING EASTERLY WINDS AND MAINLY CLEAR SKIES. CLOUDS ASSOCIATED
WITH THE BROAD AREA OF ISENTROPIC LIFT AHEAD OF THE SFC LOW VOER S
CNTRL N DAKOTA HAD SPREAD INTO FAR WRN UPPER MI WITH MAINLY ONLY
HIGH CLOUDS TO THE EAST.
MODELS WERE CONSISTENT IN TAKING THE DAKOTAS MID LEVEL LOW TO THE SE
TOWARD THE OH VALLEY BY TUE EVENING WITH BEST Q-VECT CONV AND
WAA/ISENTROPIC LIFT STAYING SE OF UPPER MI CLOSER TO THE TRACK OF
THE LOW AND ASSOC INVERTED SFC TROUGH. SO...MUCH OF THE CWA SHOULD
SEE LITTLE OR NO SYNOPTIC SCALE PCPN. CHANCE POPS STILL WERE
RETAINED OVER THE WEST WITH LITTLE IF ANY SNOW ACCUMULATION EXPECTED.
HOWEVER...HIGHER RES MODELS SUGGEST THAT AS NE FLOW STRENGTHENS AND
BECOMES MORE CYCLONIC PULLING 925-800 MB MOISTURE NE OF LAKE
SUPERIOR BACK INTO THE AREA...THE POTENTIAL FOR LAKE ENHANCED SNOW
INTO N CNTRL UPPER MI WILL INCREASE. WITH TEMPS NEAR THE 900 MB
INVERSION HEIGHT (NEAR 3K FT) ONLY AROUND -12C...BOTH INSTABILITY
AND SLR VALUES WILL BE MARGINAL FOR SIGNFICANT SNOW.
HOWEVER...UPSLOPE FLOW INTO THE HIGHER TERRAIN SHOULD BE ENOUGH TO
SUPPORT -SHSN BY TUE AFTERNOON WITH ACCUMULATIONS LESS THAN A HALF
INCH.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 356 PM EST MON MAR 4 2013
THE GENERALLY QUIET MARCH WEATHER CONTINUES THROUGH MUCH OF THE
LONG TERM PERIOD.
EXPECT SOME SNOW SHOWERS TO BE AFFECTING THE AREA
TUESDAY NIGHT INTO WEDNESDAY AS A LINGERING SURFACE TROUGH IS LEFT
BEHIND THE CLIPPER SYSTEM SLIDING TO THE SOUTH OF THE AREA TODAY
THROUGH TUESDAY. ALTHOUGH THE SYSTEM WILL BE TO THE SOUTH OF THE
AREA...DEEPER MOISTURE ROTATING WEST FROM THE LOW NEAR THE NEW
ENGLAND STATES WILL PROVIDE ENOUGH MOISTURE FOR SNOW TO DEVELOP
TUESDAY AFTERNOON INTO TUESDAY NIGHT. H850 TEMPERATURES OF -11C OVER
THE WEST AND -8C OVER THE EAST SHOULD BE COLD ENOUGH FOR LAKE
ENHANCEMENT...ESPECIALLY WITH THE ABUNDANT MOISTURE. IN
ADDITION...WITH THE LINGERING SURFACE TROUGH SLOWLY SLIDING ACROSS
THE AREA AND THE LEFTOVER NORTHERN STREAM SHORTWAVE AND ASSOCIATED
HEIGHT FALLS MOVING EAST ACROSS THE NORTHERN HALF OF THE
CWA...EXPECT A PERIOD OF LIGHT SNOW SHOWERS FOR THE WEST/CENTRAL
UPPER MICHIGAN TUESDAY NIGHT INTO WEDNESDAY. CYCLONIC
NORTH-NORTHEAST SFC-925 WINDS WOULD FAVOR THE NORTHWEST HALF OF
UPPER MICHIGAN FOR THE POPS. DID BUMP POPS UP SOME OVER THE
KEWEENAW FOR LATE TUESDAY NIGHT INTO WEDNESDAY MORNING...AS THERE
IS ADDITIONAL FORCING ALOFT FROM THE SHORTWAVE. SNOW RATIOS LOOK TO
BE ON THE LOW SIDE FOR MOST OF THE AREA...AT OR BELOW 10-1...SINCE
THE CLOUDS STRUGGLE TO GET ABOVE -10C. THERE IS A POTENTIAL FOR
SLIGHTLY HIGHER RATIOS OVER THE KEWEENAW DUE TO THE SYNOPTIC
FORCING...TOWARDS 15-1...BUT BEST FORCING LOOKS TO BE ABOVE THE DGZ
IN THAT AREA TO KEEP RATIOS FROM GETTING TOO HIGH. THE TROUGH
SLIDING EAST ON WEDNESDAY WILL TRANSITION THE LINGERING CLOUDS/SNOW
TO THE NORTHWEST WIND FAVORED LOCATIONS. MOST LOCATIONS WILL SEE A
LIGHT DUSTING OF SNOW BY WEDNESDAY EVENING...BUT SLIGHTLY HIGHER
AMOUNTS OF 1-2 INCHES ARE POSSIBLE OVER THE KEWEENAW AND THE HIGHER
TERRAIN OF MARQUETTE COUNTY.
THIS LINGERING TROUGH AND SHORTWAVE WILL SLIDE TO THE EAST OF THE
AREA ON WEDNESDAY...AS HIGH PRESSURE SLIDES EAST AND OVER THE UPPER
GREAT LAKES FOR WEDNESDAY NIGHT INTO THURSDAY BEFORE PUSHING EAST
ON FRIDAY. THIS HIGH SHOULD LEAD TO GRADUALLY DECREASING CLOUDS
DURING THAT PERIOD. ONCE AGAIN...THE POTENTIAL IS THERE FOR SOME
LINGERING FLURRIES OR STRATOCU STUCK BELOW THE INVERSION AROUND
2.5KFT. WILL PROBABLY BE SOMETHING SIMILAR TO THIS MORNINGS CLOUDS
FOR LOCATIONS FAVORED BY NORTH-NORTHWEST FLOW WEDNESDAY NIGHT INTO
THURSDAY. BUT WITH WINDS WEAKENING UNDER THE HIGH AND INCREASING DRY
AIR MOVING IN...WOULD THINK THAT THE LOW CLOUDS WOULD BE NEARLY GONE
ON THURSDAY NIGHT. WEDNESDAY NIGHT LOWS ARE TRICKY...SINCE THEY WILL
DEPEND ON WHERE THE CLOUDS ARE LOCATED. WHERE SKIES ARE
CLEAR...LIGHT WINDS AND PWAT VALUES TOWARDS 50 PERCENT OF NORMAL
WOULD LEAD TO GOOD RADIATIONAL COOLING. UPPER RIDGE WILL ALSO BUILD
OVER THE AREA DURING THIS TIME AND PRODUCE GRADUALLY WARMING
TEMPERATURES ALOFT...ESPECIALLY HEADING INTO THE WEEKEND AS
SOUTHERLY FLOW INCREASES WITH THE HIGH SLIDING TO THE EAST OF THE
AREA. THIS SHOULD TRANSITION THE AREA AWAY FROM THE BELOW NORMAL
TEMPERATURES THAT WE HAVE BEEN IN AND MORE NORMAL OR SLIGHT ABOVE
NORMAL HIGHS.
AS FOR PRECIPITATION HEADING INTO THE WEEKEND...THE CHANCES ALL
DEPEND ON THE STRENGTH OF THE UPPER RIDGE. THE FIRST SHORTWAVE WILL
RIDE UP THE UPPER RIDGE ON FRIDAY AND HEAD NORTHEAST TOWARDS JAMES
BAY ON FRIDAY NIGHT. 06Z GFS AND 00Z GEM HAVE IT FARTHER TO THE
SOUTHEAST AND MOVING ACROSS LAKE SUPERIOR...WHILE THE 00Z ECMWF
KEEPS IT WELL TO THE NORTHWEST IN ONTARIO. WITH THE SURFACE LOW
WELL TO THE NORTH OF THE AREA...SHOULD SEE A SURFACE TROUGH
PUSHING THROUGH THE AREA ON LATE FRIDAY NIGHT INTO SATURDAY. MODELS
VARYING ON TIMING AND AMOUNT OF MOISTURE ASSOCIATED WITH THE
SHORTWAVE AND THEN THE SURFACE TROUGH. THEY DO AGREE THAT DEEP
MOISTURE FOR WIDESPREAD SNOW SEEMS MARGINAL AND MORE LIKELY SEE
ISOLATED TO SCATTERED SNOW SHOWERS DURING THAT PERIOD.
UNCERTAINTY GROWS AFTER SATURDAY...AS THERE ARE LARGE MODEL AND
RUN-TO-RUN DIFFERENCES IN THE HANDLING OF THE UPPER LOW OVER THE
SOUTHWESTERN CONUS AND HOW THE NORTHERN AND SOUTHERN JET STREAMS
PHASE AS THE TROUGH SLIDES EAST. MODELS HAVE A DIFFICULT TIME WITH
PHASING SYSTEMS A DAY OR TWO OUT...SO DON/T HAVE ANY CONFIDENCE TO
GO MORE THAN A CONSENSUS CHANCE POPS FOR MONDAY WITH THE LOW MOVING
THROUGH THE GREAT LAKES. DESPITE THESE DIFFERENCES...BOTH THE LONGER
RANGE GFS/ECMWF DO SHOW THE UPPER TROUGH REESTABLISHING OVER THE
CENTRAL CONUS BY THE MIDDLE OF NEXT WEEK. THIS PRODUCES A POTENTIAL
FOR ANOTHER BELOW NORMAL TEMPERATURE PERIOD FOR THE UPPER GREAT
LAKES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1217 AM EST TUE MAR 5 2013
EXPECT SNOW SHOWERS TO BEGIN LATE TONIGHT AT ALL THREE TAF SITES.
LOW PRESSURE WILL MOVE FROM THE NORTHERN PLAINS INTO THE OHIO VALLEY
OVERNIGHT AND TUESDAY. THIS WILL BRING SOME HIGH-MID LEVEL CLOUDS TO
THE AREA OVERNIGHT...AND LIMITED SUPPORT FOR SNOW AT IWD TONIGHT.
OTHERWISE...THIS SYSTEM WILL ALLOW SURFACE WINDS TO REMAIN EAST TO
NORTHEASTERLY INTO TOMORROW. AS A RESULT...LAKE EFFECT SNOW SHOWERS
WILL DEVELOP LATE TONIGHT AND LAST THROUGH TUESDAY AT ALL THREE
SITES. OVERALL...CONDITIONS SHOULD BE VFR THROUGH THE EARLY EVENING
TONIGHT...THEN DETERIORATE TO LOW END MVFR TOWARDS MORNING. LOW END
MVFR WILL BE THE RULE THROUGH THE REMAINDER OF THE DAY
TUESDAY...ESPECIALLY TOWARDS THE EVENING HOURS. SOME OF THE MODEL
GUIDANCE SUGGESTS IFR CONDITIONS DEVELOPING AFTER 3Z...HOWEVER
CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF AT THIS TIME.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EST MON MAR 4 2013
AS LOW PRESSURE OVE THE DAKOTAS SLIDES TO THE SE...NE WINDS TO 30
KTS ARE EXPECTED MON NIGHT THROUGH TUE...ESPECIALLY OVER THE WRN
THIRD OF THE LAKE WHERE LOW LEVEL CONV IS STRONGEST. NORTH WINDS TO 25 KTS
CONTINUE THROUGH TUESDAY NIGHT. DUE TO THE GUSTY WINDS AND COLDER
TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT TIMES THROUGH
WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 20 KTS LATER
WEDNESDAY INTO FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...MCD
MARINE...JLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1202 AM CST TUE MAR 5 2013
.UPDATE...
THE TIMING OF THE WIND ADVISORY IN SPOTS AS ORD HAS JUMPED TO
ADVISORY CRITERIA THE PAST HOUR AND HRRR IS INDICATING THESE
STRONG GUSTY WINDS WILL NOT RELAX MUCH...IF ANY...OVERNIGHT. OTHER
THAN INCREASING THE WIND FORECAST FOR THE OVERNIGHT HOURS...THE
REMAINDER OF THE FORECAST APPEARS TO BE ON TRACK AND NO ADDITIONAL
CHANGES WERE NECESSARY WITH THE UPDATE.
&&
SHORT TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 307 PM CST MON
MAR 4 2013
FOCUS DURING THE SHORT TERM PERIODS IS ON WINDS.
WATER VAPOR IMAGERY INDICATES A CLOSED UPPER LOW PRESSURE SYSTEM IN
THE WESTERN DAKOTAS...SHORTWAVE RIDGING IN THE PACIFIC NORTHWEST
WITH AN UPSTREAM UPPER LOW STILL OUT IN THE PACIFIC. AT THE SURFACE
LOW PRESSURE CENTERS WERE LOCATED IN SOUTH CENTRAL NORTH DAKOTA AS
WELL AS EASTERN OK. THE INITIAL COLD FRONTAL BOUNDARY WHICH CROSSED
OUR REGION OVERNIGHT WAS LOCATED FM EASTERN KS TO THE OK
PANHANDLE...WITH THE SECONDARY STRONGER COLD FRONT STRETCHING FROM
WESTERN SD TO SW NEB EARLY THIS AFTN.
NORTHWEST WINDS WERE STEADY/GUSTY ESPECIALLY THIS MORNING IN A TIGHT
PRESSURE GRADIENT FOLLOWING THE PASSAGE OF COLD FRONT
OVERNIGHT/COLD FRONT NUMBER ONE. THE SFC GRADIENT HAS RELAXED SOME
THIS AFTN WITH SOME DECREASE IN WIND SPEEDS NOTED. THE DEEPER
MIXING TODAY HAS ALLOWED TEMPS TO CLIMB TO THE MID/UPPER 40S. RADAR
RETURNS HAVE BEEN PICKING UP ON MID CLOUD COVER BUT RETURNS HAVE
ENHANCED THE LAST SEVERAL SCANS. ISOLATED SHOWERS/SPRINKLES ARE
NOT OUT OF THE QUESTION ESPECIALLY ACROSS THE SOUTHERN HALF OF OUR
CWA IN PRESENCE OF MID LEVEL FRONTOGENESIS AND LIFT ENHANCED AS
ENERGY ROUNDS BASE OF TROUGH...WHILE UPPER LOW TRANSLATES SE. LOW
POPS FOR ISOLATED -SHRA HAVE BEEN MAINTAINED THRU THE EVENING AND
FIRST PART OF THE NIGHT.
HEADING INTO TONIGHT...A STRONGER COLD FRONT/COLD FRONT NUMBER TWO
SWEEPS SOUTHEAST AFTER DARK WITH 6HR PRESSURE RISES AVERAGING 5 TO
7MB INITIALLY BEHIND THE FRONT. FORECAST SOUNDINGS MIX OUT LLVL
INVERSION AFTER 06Z AND ALTHOUGH COULD SEE SOME STRONG WINDS WITH
FROPA...LOOKING AT MORE SUSTAINED GUSTY WINDS HEADING INTO THE
OVERNIGHT TIME FRAME ON THE BACK SIDE OF THE UPPER LOW WHICH IS
PROGGED TO BE NEAR NE NEB 12Z TUESDAY. WITH INCREASING NW WINDS
TONIGHT AND WINDS REMAINING STRONG/GUSTY THRU AT LEAST THE FIRST
PART OF THE DAY ON TUESDAY...WILL GO AHEAD WITH A WIND ADVISORY
FOR OUR NORTHERN/EASTERN ZONES WHERE GRADIENT WILL BE TIGHTER IN
PROXIMITY TO THE LOW AND FORECAST SOUNDINGS INDICATE MIXING
BETWEEN H825 AND H85 WITH WINDS AT THE TOP OF THE LAYER AOA 40KTS.
SREF WIND PROBS INDICATE DECENT CHCS FOR REACHING WIND ADV
CRITERIA AND MOS GUIDANCE ALSO INDICATES POTENTIAL FOR NEAR/ABOVE WIND
ADV WINDS FOR SEVERAL HOURS. WIND SPEEDS IN OUR WESTERN ZONES MAY
DROP OFF EARLIER IN AFTN THAN HEADLINE INDICATES BUT PREFER TO
HAVE A ROW OF COUNTIES AS A BUFFER ACROSS OUR WEST/SOUTH ATTM. IN
CAA TUESDAY...GENERALLY EXPECT HIGHS TO AVERAGE IN THE MID/UPPER
30S. PCPN CHCS TUESDAY LOOK TO FAVOR LOCATIONS EAST OF OUR CWA
WHERE SOME FLURRIES/LIGHT SNOW SHOWERS ARE NOT OUT OF THE
QUESTION.
LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 307 PM CST MON
MAR 4 2013
TUESDAY NIGHT THROUGH MONDAY. MAIN FORECAST CONCERNS
WILL BE PRECIPITATION CHANCES FOR THE WEEKEND AND TEMPERATURES
THROUGH THE PERIOD.
AN UPPER LEVEL RIDGE IN THE WESTERN CONUS WILL DRIFT TO THE EAST
TUESDAY NIGHT THROUGH THURSDAY NIGHT. DURING THIS TIME A SURFACE
HIGH WILL MOVE TO THE EAST TUESDAY NIGHT WITH A TIGHTENING SURFACE
PRESSURE GRADIENT AS A SURFACE LOW DEVELOPS TO THE WEST. SOUTH WINDS
WILL INCREASE ACROSS THE AREA ON WEDNESDAY AND WILL CONTINUE THROUGH
THURSDAY NIGHT. EXPECT SOME BREEZY CONDITIONS...BUT MOST MODELS ONLY
HAVE 30 TO 35 KNOTS AT 850 MB SO DO NOT EXPECT VERY STRONG WINDS.
WITH THE SOUTH WINDS...SOME WARM ADVECTION AND THE UPPER RIDGE
MOVING THROUGH THE AREA...TEMPERATURES WILL BE WARMER AGAIN WITH
WARMER TEMPERATURES ON THURSDAY THAN WEDNESDAY.
THURSDAY NIGHT INTO FRIDAY THERE IS AN UPPER LEVEL WAVE THAT MOVES
INTO THE RIDGE AND THE SURFACE LOW AND COLD FRONT MOVE INTO THE
AREA. EXPECT AN INCREASE IN THE CLOUDS BUT TEMPERATURES WILL BE A
LITTLE COOLER IN THE NORTH BUT ABOUT THE SAME FOR THE SOUTH.
THE MODELS TAKE ON SOME FAIRLY SIGNIFICANT DIFFERENCES FOR THE
EXTENDED PERIOD. SOME OF THE DIFFERENCES START EVEN ON FRIDAY. AN
UPPER LOW PRESSURE SYSTEM WILL BE MOVING INTO THE PLAINS AND BRING A
CHANCE FOR PRECIPITATION TO THE AREA FROM FRIDAY NIGHT INTO MONDAY.
THE GFS IS MORE PROGRESSIVE WHILE THE LATEST RUN OF THE ECMWF SLOWS
THE CLOSED LOW DOWN AND LINGERS IT TO THE WEST WHILE THE GFS PUSHES
IT THROUGH INTO THE GREAT LAKES BY MONDAY EVENING. EXPECT THERE TO
BE PRECIPITATION STARTING FRIDAY NIGHT. THE BEST CHANCE WILL BE
SATURDAY AND SATURDAY NIGHT. HAVE LESS CHANCES FOR SUNDAY THROUGH
MONDAY. THE NEXT QUESTION WILL BE PRECIPITATION TYPE. TEMPERATURES
ARE FAIRLY WARM FRIDAY NIGHT THROUGH SUNDAY AND THERE IS A LITTLE
INSTABILITY SO HAVE WENT WITH SHOWERS. THE GFS HAS UP TO 300 J/KG.
THERE COULD BE AN ISOLATED LIGHTNING...BUT IT IS JUST A SMALL CHANCE
AND WITH THE MODELS HAVING SO MANY DIFFERENCES WILL JUST KEEP
SHOWERS. BY SUNDAY NIGHT THERE IS SOME COOLER AIR MOVING INTO THE
AREA AND THERE COULD BE SOME RAIN OR SNOW MIXED FOR SUNDAY NIGHT
INTO MONDAY.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1150 PM CST MON MAR 4 2013
WHILE CONFIDENCE IS HIGH IN UNRESTRICTED VISIBILITY THROUGH THE
PERIOD...THE PRIMARY MODIFICATION FROM PREVIOUS TAF ISSUANCE
INVOLVES THE INTRODUCTION OF A HIGH-END MVFR CEILING FOR UP TO A
7-HOUR PERIOD FROM 09Z TO 16Z THIS MORNING...AS STRATUS ADVECTS
SOUTHWARD OUT OF SOUTH DAKOTA ON THE BACK SIDE OF A STRONG MID
LEVEL LOW PRESSURE SYSTEM. THIS MVFR CEILING IS NOT A CERTAINTY BY
ANY MEANS...AS KGRI COULD BE VERY CLOSE TO ITS FAR WESTERN
EDGE...AND POTENTIALLY MISS OUT...SO TRENDS WILL BE MONITORED
CLOSELY. A FEW FLURRIES ARE POSSIBLE WITH THIS STRATUS...BUT HAVE
NOT INCLUDED IN THE TAF. ASSUMING ANY LOW CLOUDS VACATE BY MID-
DAY...THE LATTER 12 HOURS OF THE PERIOD SHOULD FEATURE ESSENTIALLY
CLOUD-FREE SKIES. OTHERWISE...STRONG NORTHWEST WINDS WILL REMAIN
AN ISSUE ESPECIALLY THROUGH THE NEXT 18 HOURS...WITH SUSTAINED
SPEEDS GENERALLY RANGING FROM AT LEAST 20-25 KT AND FREQUENTLY
GUSTING AT LEAST 29-35KT...AND GENERALLY PEAKING IN INTENSITY
BETWEEN SUNRISE AND NOON. A STEADY DECREASE IN WIND SPEEDS WILL
TAKE PLACE THROUGH THE LATE AFTERNOON/EVENING...AND EASING BELOW
10KT AFTER SUNSET.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM 4 AM TO 3 PM CST TUESDAY FOR NEZ041-048-049-
062>064-074>077.
WIND ADVISORY UNTIL 3 PM CST TUESDAY FOR NEZ039-040-046-047-061.
KS...NONE.
&&
$$
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1118 PM CST MON MAR 4 2013
.UPDATE...
LIGHT PRECIPITATION WILL CONTINUE TO MOVE OUT OF SOUTHWEST IOWA
AND FAR SOUTHEAST NEBRASKA THROUGH ABOUT 2 AM. ANY SNOW FALLING
WILL REDUCE VISIBILITIES FOR A TIME...BUT WITH TEMPERATURES
REMAINING ABOVE FREEZING WHILE PRECIPITATION IS FALLING...SHOULD
NOT SEE ANY ACCUMULATION. THEN STRONG NORTHWEST WINDS WILL SPREAD
ACROSS THE AREA BEFORE SUNRISE...WITH GUSTS OVER 35KT LIKELY
BEFORE 12Z IN NORTHEAST NEBRASKA. STRONG WINDS WILL OVERSPREAD THE
REST OF EASTERN NEBRASKA AND SOUTHWEST IOWA...AND AN EXPANSION OF
WIND ADVISORY MAY BE NEEDED WITH MORNING FORECAST PACKAGE.
&&
.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.
BAND OF LIGHT SNOW WAS MOVING EAST OF THE KOMA AREA BEFORE
06Z...SO MAINLY VFR CONDITIONS ARE EXPECTED THROUGH SUNRISE. A
STRONG LOW PRESSURE SYSTEM WILL INCREASE NORTHWEST WINDS INTO THE
25 TO 35KT RANGE AT ALL TAF SITES BY MID MORNING. MVFR CIGS NEAR
FL025 ARE LIKELY THROUGH THE DAY AS WELL. THE CLOUDS AND WINDS
WILL DECREASE IN COVERAGE/INTENSITY LATE IN THE AFTERNOON.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 335 PM CST MON MAR 4 2013/
SHORT TERM...TONIGHT THROUGH THURSDAY
THE PRIMARY FORECAST CONCERNS DURING THIS PERIOD ARE PCPN AND WINDS
TONIGHT...WINDS ON TUESDAY AND POTENTIAL FOR CLOUD COVER FOR TUESDAY
NIGHT.
CLOSED LOW AT 500 MB WHICH WAS OVER EXTREME EASTERN MONTANA AT 12Z
WILL CONTINUE TO DIVE SOUTHEAST TONIGHT...REACHING THE BORDER AREA
OF SOUTH DAKOTA/MINNESOTA/IOWA BY 12Z TUESDAY AND THEN SOUTHERN
ILLINOIS BY 00Z WEDNESDAY. SURFACE ANALYSIS EARLY THIS AFTERNOON
SHOWED ONE LOW PRESSURE CENTER OVER SOUTH CENTRAL NORTH DAKOTA AND
ANOTHER OVER OKLAHOMA. AN INVERTED TROF EXTENDED NORTHWARD FROM
THE SOUTHERN LOW. NORTHERN LOW WILL PUSH SOUTHEAST AND WEAKEN
OVERNIGHT. FAIRLY TIGHT PRESSURE GRADIENT OVER THE AREA ALONG WITH
DECENT DOWNWARD MOMENTUM TRANSFER SHOULD RESULT IN GUSTY WINDS
LATER TONIGHT AND INTO TUESDAY. WILL LEAVE PREVIOUSLY ISSUED WIND
ADVISORY IN PLACE BUT EXTEND IT UNTIL 21Z. THIS CAN BE CANCELED IS
WINDS DECREASE EARLIER. ALSO ISSUED ANOTHER WIND ADVISORY SEGMENT
TO THE SOUTHEAST OF PREVIOUS ADVISORY FROM 8 AM TO 3 PM
TUESDAY...AS STRONGER WINDS OVERSPREAD MORE OF THE AREA.
RADAR ECHOES HAVE BEEN INCREASING TO OUR WEST...WITH SOME LIGHT SNOW
REPORTED IN PARTS OF SOUTHWEST NEBRASKA. RECENT HRRR AND RAP13 MODEL
RUNS INDICATE SOME PCPN WILL DEVELOP OVER ABOUT THE SOUTHEAST HALF
OF THE FORECAST AREA THIS EVENING...IN ASSOCIATION WITH 500-300 MB
Q VECTOR DIVERGENCE AND ELEVATED FRONTOGENESIS. RAP13 PCPN
AMOUNTS SEEM OVERDONE...BUT SCENARIO IS ALSO SUPPORTED BY 18Z NAM.
ON TUESDAY...FAIRLY TIGHT PRESSURE GRADIENT IS IN PLACE DURING THE
MORNING BUT THIS RELAXES IN THE AFTERNOON. THERE IS SOME SMALL
POTENTIAL FOR LIGHT SNOW TUESDAY...MAINLY FOR ABOUT THE NORTHEAST
ONE THIRD OF THE FORECAST AREA...BUT CHANCES ARE MUCH HIGHER FARTHER
TO THE EAST OF OUR AREA.
OTHERWISE...LOOK FOR MAINLY DRY CONDITIONS TUESDAY NIGHT AS HIGH
PRESSURE BUILDS IN. SOME MODELS SHOW LOW LEVEL MOISTURE MOVING INTO
THE AREA FROM THE NORTH...SO WILL HAVE TO WATCH THAT. FOR NOW...
HAVING CLEARING SKIES. THAT SURFACE RIDGE WILL PUSH OFF TO THE EAST
WEDNESDAY THROUGH THURSDAY WITH INCREASING SOUTH/SOUTHEAST WINDS...
MODERATING TEMPERATURES AND MAINLY DRY CONDITIONS.
MILLER
LONG TERM...THURSDAY NIGHT THROUGH MONDAY.
CONFIDENCE IS INCREASING THAT THE UPPER LEVEL LOW THAT WILL DIVE
INTO THE SOUTHWEST CONUS ON WED/THU WILL MOVE INTO THE PLAINS AT
SOME POINT NEXT WEEKEND. THE ECMWF/GEM HAVE REMAINED VERY CONSISTENT
OVER THE PAST COUPLE OF DAYS WHILE THE OPERATIONAL GFS HAS VARIED
WILDLY FROM THE 00Z/04 TO 12Z/O4 RUNS. THUS WILL LEAVE MUCH HEAVIER
ON THE EC/GEM/EC ENSEMBLE SOLUTIONS FOR THE TRACK OF THIS SYSTEM.
AHEAD OF THE SYSTEM/COLD FRONT WE SHOULD SEE A NICE DAY ON FRIDAY
WITH HIGHS ABOVE SEASONAL AVERAGES. THE COLD FRONT THEN MOVES
THROUGH THE FA ON THE WEEKEND WITH SLIGHTLY COOLER AIR MOVING INTO
THE REGION. THE GFS...ALTHOUGH CLOSER TO THE EC WITH THE 12Z/04
RUN...IS STILL TO FAST IN BRINGING PRECIP TO THE AREA. WILL HOLD
ONTO SOME POPS IN THE SW ON FRI NIGHT...BUT IT WILL LIKELY BE SAT OR
MAYBE EVEN SAT NIGHT BEFORE WE SEE THE BULK OF THE PRECIP ASSOCIATED
WITH THE UPPER LEVEL LOW HEAD INTO THE PLAINS.
THE EC IS VERY WARM FOR THIS SYSTEM AND WOULD HAVE LIMITED CHANCE OF
ANY FROZEN PRECIP AT ALL FOR OUR FA...AND WE WILL TREND THE FORECAST
THIS WAY. HAVE INCREASED OVERNIGHT LOWS AS WELL AS HIGHS A TOUCH FOR
MOST AREAS. REMOVED FZRA MENTION AND WENT WITH A RA/SN MIX IN THE
FAR NORTH AND OTHERWISE JUST RA OVER THE SRN 2/3RD OF THE FA. IT IS
IMPORTANT TO NOTE THAT THE FORECAST WILL HAVE CHANCES OF PRECIP FOR
SEVERAL PERIODS...BUT THIS MORE REFLECTS THE UNCERTAINTY IN THE
TIMING MORE THAN WE WILL HAVE CONTINUOUS RAIN OVER A 48 HOUR
PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM 8 AM TO 3 PM CST TUESDAY FOR NEZ015-032>034-
042>045-050-051-065-066-078.
WIND ADVISORY UNTIL 3 PM CST TUESDAY FOR NEZ011-012-016>018-030-
031.
IA...WIND ADVISORY FROM 8 AM TO 3 PM CST TUESDAY FOR IAZ043.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1027 PM EST WED MAR 6 2013
.SYNOPSIS...
A WINTER STORM WILL MOVE OFF THE MID ATLANTIC COAST AND SLOW DOWN
AS IT MOVES UP THE NORTHEASTERN SEABOARD TONIGHT THROUGH THURSDAY
NIGHT. AN UPPER LEVEL LOW WILL TRACK SOUTHEAST FROM THE UPPER
GREAT LAKES TONIGHT THROUGH THURSDAY NIGHT AND SPREAD MORE SNOW TO
MUCH OF CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA THURSDAY
AFTERNOON AND NIGHT. THE SNOW COULD MIX WITH RAIN AT TIMES IN THE
VALLEYS THURSDAY AFTERNOON. ALL THE PRECIPITATION WILL TAPER OFF
FRIDAY. HIGH PRESSURE AND MILDER WEATHER WILL MOVE INTO THE REGION
FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH EARLY THURSDAY MORNING/...
RECENT RADAR TRENDS SHOWING ANY LINGERING SNOW ACTIVITY QUICKLY
EXITING OFF THE EAST COAST THIS EVENING AS MAIN SFC LOW CONTINUES
TO EXIT TOWARDS THE 40N/70W BENCHMARK. LATEST HRRR AND NEWLY
ARRIVING 00Z NAM BOTH VALIDATE CURRENT RADAR TRENDS AND KEEP ANY
QPF OVERNIGHT EAST OF THE CWA. AS A RESULT...HAVE TRIMMED BACK ON
POPS ACCORDINGLY AND FEEL MUCH IF NOT THE WHOLE NIGHT SHOULD BE
PRECIP FREE. ASIDE FROM THAT...HOURLY TEMPS ADJUSTED AS COLD AIR
ADVECTION ON BACKSIDE OF DEPARTING LOW HAS YET TO ARRIVE. BY EARLY
MORNING...LOWS SHOULD BOTTOM OUT TOWARDS THE UPPER 20S ACROSS MOST
LOCATIONS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
1025 PM UPDATE...
NEWLY ARRIVING 00Z MODEL GUIDANCE FURTHER SUPPORTING CONCERNS FOR
SNOWFALL BEGINNING LATE THURSDAY AFTERNOON AS WRAP AROUND MOISTURE
ON THE BACKSIDE OF AFOREMENTIONED UPPER LOW GETS PULLED WESTWARD
IN ADVANCE OF ANOTHER NORTHERN STREAM TROUGH/CLOSED LOW DIVING
SOUTHEAST FROM THE NORTHERN LAKES. IN FACT...LATEST WATER VAPOR
IMAGERY NOW SHOWING THE APPROACHING WAVE QUITE WELL AND THIS
FEATURE WILL CONTINUE DIVING SOUTHEAST THROUGH CENTRAL PA THU
NGT/EARLY FRI. 24-HR QPF TOTALS FROM THE NAM SUGGEST OVER 1" OF
WATER EQUIVALENT FOR THE EASTERN ZONES...WITH UP TO .7" AS FAR
WEST AS THE I-81 CORRIDOR. FOR WHAT ITS WORTH...18Z GFS ALSO
SHOWING SOME WESTWARD DISPLACEMENT OF MAIN QPF AXIS WHICH LENDS
SUPPORT TO AT LEAST HIGH-END ADVISORY SNOWFALLS FOR THE EASTERN
ZONES. FOR NOW...WILL HOLD OFF ON MAKING ANY WHOLESALE CHANGES AND
ALLOW THE OVERNIGHT SHIFT TO EVALUATE THE FULL MODEL SUITE BEFORE
MAKING ANY HEADLINE ADJUSTMENTS.
PREVIOUS SHORT TERM DISCUSSION...
WATER VAPOR IMAGERY SHOWS A POTENT UPPER LEVEL LOW DIVING
SOUTHEASTWARD FROM THE UPPER GREAT LAKES AT PRESENT. THIS FEATURE
WILL CONT SE REACHING WRN NY THU EVE AND THEN DOWN TO THE DELMARVA
PENINSULA BY 12Z FRI. MEANWHILE THE LARGE CYCLONE THAT WAS MOVG
THRU THE MID- ATLANTIC STATES AT PRESENT WILL MOVE OFFSHORE BUT
SLOW DOWN AND EXPAND ITS LOW TO MID LEVEL EASTERLY FLOW TO
ENCOMPASS ALL OF C NY AND NE PA THU AFTERNOON AND NIGHT. MOISTURE
ADVECTION IN THIS LOW TO MID LEVEL EASTERLY FLOW WILL RISE
ISENTROPICALLY ESP ACRS ERN NY AND NE PA AS THE UPPER LEVEL LOW
MOVING SE ALSO LIFTS THE ISENTROPES. THIS IS AN EXCELLENT
DYNAMICAL SET-UP TO FORCE PRECIPITATION OVER MUCH OF C NY/NE PA
LATE THU AFTERNOON AND NIGHT. SINCE MOST OF THE PRECIPITATION WILL
FALL AT NIGHT AND ALSO FOCUS ON OUR HIGHER TERRAIN AREAS IN
OTSEGO...DELAWARE AND SULLIVAN CO/S IT WILL BE MAINLY SNOW.
HEAVIEST PRECIPITATION WILL BE IN OUR EASTERN ZONES WHERE THE
LIFTG WILL BE THE HIGHEST AND THE MOISTURE WILL BE DEEPER.
HENCE OPTED FOR A WINTER WX ADVY IN DELAWARE...OTSEGO AND SULLIVAN
CO/S THU PM TO FRI AM GIVEN THE CONSENSUS OF THE 12Z GFS...12Z
CMC...12Z HI RES NMM...AND THE 15Z SREF. BLENDED MODEL SNOWFALL
FROM THESE SOURCES AND CAME UP WITH BASICALLY 3-4 INCHES IN THE
DEEPEST VALLEYS OF DELAWARE...SULLIVAN AND OTSEGO CO/S TO 6-8
INCHES OVER THE HIGHEST TERRAIN. MOST OF THESE COUNTIES ARE FAIRLY
ELEVATED SO MOST AREAS LIKELY WILL SEE 4-6 INCHES. REST OF C NY
AND NE PA LIKELY WILL SEE LESS THAN 1 INCH IN VALLEYS TO AS MUCH
AS 3 INCHES HIGHER TERRAIN ALONG THE I-81 CORRIDOR IN NY. WE
DISCOUNTED THE NAM WHICH BURIES THE POCONOS AND CATSKILLS WITH
10-20 INCHES OF SNOW AND GIVES A LARGE PART OF THE REST OF OUR
AREA 5-10 INCHES OF SNOW. BUT THIS TYPE OF SCENARIO DOES BEAR
WATCHING AS THEIR IS STRG MID-LVL FGEN FRCG IN THE PRESENCE OF
WEAK TO NEGATIVE EPV IN THESE AREAS. FOR NOW WAY TOO UNCERTAIN TO
JUMP ON THIS BAND WAGON AND GIVEN THE TRACK RECORD OF THE NAM/S
SNOWFALL RECENTLY WE DID NOT USE FOR NOW.
THE SNOW PEAKS THURSDAY NIGHT AND TAPERS DOWN TO SNOW SHOWERS
FLURRIES AND POTENTIALLY EVEN SOME SPRINKLES/RAIN SHOWERS IN THE
LOWER ELEVATIONS FRIDAY.
FRIDAY NIGHT AND SATURDAY LOOK FAIR WITH MILDER TEMPERATURES ON
SATURDAY AS A RDG OF HIGH PRESSURE BUILDS IN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GIVEN TDA`S FOCUS ON SHORT TERM CONCERNS...WE USED HPC GUIDANCE
FOR THE MED RNG. WE DID MAKE SOME MINOR TWEEKS...PRIMARILY TO CLD
COVER (MORE PESSIMISTIC) AND TO A LESSER XTNT WINDS AND TEMPS AS A
BACK DOOR CDFNT TRIES TO DROP SWD ON SUN NGT. THIS FEATURE COULD
HAVE A SIG EFFECT ON TEMPS ACRS NRN ZONES ON MON...IN ADVANCE OF
THE OCCLUDED FNT FCST TO PASS LATE ON MON NGT. AFTER SOME MILD
TEMPS THIS WEEKEND...READINGS WILL COOL BY MID WEEK TO MORE
SEASONABLE VALUES.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
02Z THU UPDATE... FOR THE MOST PART...VFR WILL PERSIST THROUGH THE
OVERNIGHT PD...AND WELL INTO THU. THE ONE PSBL EXCEPTION IS
KBGM...WHERE CIGS SHOULD AT LEAST OCNLY DROP INTO THE MVFR CAT.
IT APPEARS THAT MORE WIDESPREAD RESTRICTIONS (LWR CIGS/-SN) SHOULD
HOLD OFF TIL VERY LATE IN THE DAY THU (22Z AND BEYOND).
N TO NE WINDS SHOULD PERSIST THROUGH THE PD AT 8-15 KT (PERHAPS
GUSTY AT KAVP).
.OUTLOOK...
THU NGT INTO FRI...MVFR/IFR CONDS PSBL IN -SN/SN...SPCLY KBGM/KAVP.
FRI NGT/SAT/SUN...VFR.
MON...MVFR IN -SHRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY FROM 1 PM THURSDAY TO 11 AM EST FRIDAY
FOR NYZ046-057-062.
&&
$$
SYNOPSIS...DJN
NEAR TERM...CMG/DJN
SHORT TERM...DJN
LONG TERM...
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
937 PM EST WED MAR 6 2013
.SYNOPSIS...
A DEEP LOW PRESSURE SYSTEM WILL TRACK FURTHER OFFSHORE INTO THE
ATLANTIC ON THURSDAY. DRY HIGH PRESSURE WILL BUILD INTO THE REGION
FRIDAY THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 645 PM WEDNESDAY...
QUICK UPDATE TO CANCEL THE WIND ADVISORY AS WINDS HAVE DROPPED OFF
CONSIDERABLY (LESS THAN 30KTS)IN MOST SPOTS. OTHERWISE...CENTRAL NC
WILL SEE ANOTHER HOUR OR TWO OF LIGHT RAIN OR SPRINKLES BEFORE THE
LAST PRECIP BAND PIVOTS OFF TO THE NORTHEAST.
PREVIOUS DISCUSSION...
THROUGH TONIGHT: IMPROVING WEATHER EXPECTED TONIGHT. LATEST SURFACE
MAP SHOWS THE STRONG SURFACE LOW NEAR THE MOUTH OF CHESAPEAKE BAY.
BANDS OF RAIN AND SNOW SHOWERS CONTINUE TO PIVOT AROUND THE LOW INTO
NORTHEAST NC... ALTHOUGH THUS FAR THIS AFTERNOON -- IN CONTRAST TO
THIS MORNING`S HRRR GUIDANCE -- THE SIGNIFICANT REFLECTIVITIES HAVE
HELD LARGELY NORTH AND EAST OF OUR FORECAST AREA. EXTRAPOLATION OF
EXISTING UPSTREAM PRECIP AND LOCAL WRF OUTPUT STILL SUPPORT PRECIP
WORKING ACROSS THE NORTHEAST CWA... ALONG AND NE OF A LINE FROM
OXFORD TO WILSON... FOR THE NEXT FEW HOURS. SURFACE WET BULBS ARE
GENERALLY ABOVE FREEZING IN THIS AREA... SO EXPECT A PTYPE OF MOSTLY
RAIN... ALTHOUGH HEAVIER BANDS MAY STILL MIX WITH A LITTLE
INCONSEQUENTIAL WET SNOW IN THE FAR NORTHEAST. THE LOW SWINGS
FARTHER OUT TO SEA THIS EVENING... LEAVING LITTLE MORE THAN PATCHY
SPRINKLES BEFORE THE PRECIP THREAT ENDS ENTIRELY BY MIDNIGHT.
REGARDING THE WINDS... WE`VE HAD NUMEROUS SITES ATTAIN PEAK GUSTS OF
40-46 MPH SO FAR TODAY WITH NEARLY ALL LOCATIONS SEEING 30 MPH GUSTS
OR GREATER. THE DEPARTURE OF THE COASTAL LOW AND SUBSEQUENT SLOW
SLACKENING OF THE MSLP GRADIENT AND GRADUAL DECREASE IN NEAR-SURFACE
MIXING WILL RESULT IN SLOWLY DECREASING WINDS AS WE GO THROUGH THE
EVENING. WILL LEAVE THE WIND ADVISORY IN PLACE UNTIL MIDNIGHT...
ALTHOUGH IT MAY NEED TO BE CANCELED A FEW HOURS EARLY. EXPECT
GRADUAL CLEARING SKIES FROM SW TO NORTHEAST AS WE DRY OUT IN THE
LOWEST FEW THOUSAND FEET. DESPITE DEW POINTS IN THE 20S THROUGH
TONIGHT... THE AIR SHOULD STAY JUST STIRRED ENOUGH NEAR THE GROUND
TO KEEP LOWS UP A BIT... 29-34.
FOR THURSDAY/THURSDAY NIGHT: WITH THE COLUMN DRYING OUT AND SINKING/
STABILIZING ALOFT... EXPECT QUITE A BIT OF SUNSHINE WITH PERHAPS
SOME FLAT AFTERNOON CUMULUS. SURFACE HIGH PRESSURE CENTERED OVER
ONTARIO AND THE UPPER MIDWEST/UPPER GREAT LAKES WILL EXTEND
SOUTHWARD WITH RIDGING BUILDING SLOWLY INTO NC FROM THE NW. WINDS
FROM THE NNW WILL NOT BE NEARLY AS STRONG AS THEY HAVE BEEN TODAY
BUT THE MSLP GRADIENT REMAINS TIGHT ENOUGH TO TRANSLATE INTO SURFACE
WINDS OF 10-15 KTS AND PERIODIC GUSTS TO 15-20 KTS BASED ON
PROJECTED WINDS IN THE UPPER PORTIONS OF THE MIXED LAYER. LOW LEVEL
THICKNESSES WILL BE AROUND 20-25 METERS BELOW NORMAL... SUGGESTING
HIGHS OF 51-58... OR ROUGHLY TWO CATEGORIES BELOW NORMAL. THE MID
LEVEL LOW NEAR LAKE SUPERIOR THIS MORNING WILL DROP TOWARD THE
SOUTHEAST OVER PA/DEL LATE THURSDAY NIGHT... HOWEVER THE LACK OF
MOISTURE AT ANY LEVEL AND NO OPPORTUNITY FOR AN MOISTURE TRANSPORT
INTO NC WITH LOW LEVEL FLOW FROM THE NNW WILL ALLOW SKIES TO STAY
GENERALLY CLEAR. LOWS 28-33 WITH 4-8 KTS OF WIND FROM THE NORTH.
-GIH
&&
.SHORT TERM /FRIDAY AND SUNDAY NIGHT/...
AS OF 250 PM WEDNESDAY...
AN OMEGA BLOCK WILL DEVELOP BY FRIDAY AS THE UPPER LOW OFF THE MID
ATLANTIC COAST CONTINUES TO WOBBLE SLOWLY TOWARD THE NORTH
ATLANTIC AND A CUTOFF LOW DEVELOPS OVER THE SOUTHWESTERN US.
MEANWHILE...A DISTURBANCE CURRENTLY MOVING INTO THE UPPER GREAT
LAKES AREA WILL BE DRAWN SOUTH ACROSS THE MID-ATLANTIC STATES AND
CLIP NORTHEASTERN NC EARLY FRIDAY. DEEP MOISTURE IS FORECAST TO BE
RATHER LIMITED...BUT ENHANCE CLOUD COVER OVER AT LEAST THE NORTHERN
COASTAL PLAIN SEEMS FAIRLY LIKELY WITH THE GLANCING BLOW OF THE VORT
MAX. FORECAST SOUNDINGS ALSO SHOW PERSISTENT BACKING OF THE LOW
LEVEL FLOW...WITH 10-15KT SURFACE WIND...SUGGESTING ANOTHER SURGE OF
COLD ADVECTION BEFORE HIGH PRESSURE BUILDS IN FROM THE GREAT LAKES
FRIDAY NIGHT. THUS...WILL KEEP HIGHS A GOOD 4-6 DEGREES BELOW MOST
GUIDANCE ON FRIDAY...49-55 NORTHEAST TO SOUTHWEST. LOWS FRIDAY
NIGHT IN THE UPPER 20S TO LOWER 30S.
RIDGING ALOFT WILL BUILD OVER HEAD SATURDAY THROUGH SUNDAY...WHILE
SURFACE HIGH PRESSURE SETTLES ALONG THE EAST COAST. THIS WILL LEAD
TO A MODERATING TREND IN TEMPS AS 850MB TEMPS APPROACH 10C AND LOW
LEVEL THICKNESSES RISE ABOVE 1350M BY SUNDAY.
HOWEVER...NORTHEASTERLY LOW LEVEL FLOW IS FORECAST
TO CONTINUE SATURDAY...SO THE WARMING ALOFT MAY NOT BE COMPLETELY
REALIZED FOR YET ANOTHER DAY. THE MORE NOTICEABLE WARMUP WILL BE
FELT IN THE NORTHEAST CWA ON SATURDAY...WITH HIGHS RANGING FROM THE
MID 50S NORTHEAST TO AROUND 60 SOUTHWEST. THE SURFACE HIGH IS
FORECAST TO SHIFT OFFSHORE BY SUNDAY...AND IF THIS OCCURS...THEN
WEAK RETURN FLOW WOULD DEVELOP AND HELP PUSH HIGHS INTO THE MID
60S. DRY CONDITIONS WILL PERSIST BENEATH THE RIDGE.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 250 PM WEDNESDAY...
THE OMEGA BLOCK OVER THE CONUS IS FORECAST TO WEAKEN BY
MONDAY..ALLOWING AN UPPER LOW OVER THE SOUTHWESTERN US TO EJECT
EASTWARD ACROSS THE SOUTHERN PLAINS AND DEAMPLIFY AS IT LIFTS TOWARD
THE MIDWEST STATES . SOUTHERLY RETURN FLOW AHEAD OF THE SYSTEM
SHOULD PUSH TEMPS WELL ABOVE NORMAL MONDAY WITH LOW LEVEL THICKNESSES
PROGGED TO APPROACH 1360M. BASED ON THIS...UPPER 60S SEEM LIKELY
AND LOWER 70S POSSIBLE UNLESS CLOUD COVER IS MORE ROBUST THAN
FORECAST. AS THE UPPER TROUGH AND PRIMARY SURFACE LOW LIFT ACROSS
THE MIDWEST AND OH VALLEY...THE ATTENDANT COLD FRONT IS EXPECTED TO
MOVE CROSS THE MOUNTAINS MONDAY NIGHT/TUESDAY. THE GFS AND ECMWF
HAVE WAVERED BACK AND FORTH A BIT REGARDING THE EXACT TIMING OF THE
FRONTAL PASSAGE AND SENSIBLE WEATHER...BUT THEIR SOLUTIONS ARE
GENERALLY WITHIN 12 HOURS OF EACH OTHER. HOWEVER...THERE ARE STILL
ENOUGH DIFFERENCES IN THE MASS FIELDS TO KEEP POPS BELOW 50 PERCENT
AT THIS TIME. SHOULD ALSO NOTE THAT AS WE MOVE FURTHER INTO
MARCH...THIS TYPE OF PATTERN WILL BRING A BETTER CHANCE OF
THUNDERSTORMS ACCOMPANYING THE COLD FRONT...BUT WE WILL HOLD OFF ON
INCLUDING THUNDER IN THE FORECAST UNTIL TIMING OF THE SYSTEM AND
MOISTURE RETURN ARE MORE CERTAIN.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 900 PM TUESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD...ASIDE FROM
LINGERING MVFR CEILINGS AT THE RWI TERMINAL THROUGH 03-05Z.
NORTHWEST WINDS AT 10-15 KT WITH GUSTS UP TO TO 20-25 KT WILL REMAIN
POSSIBLE THROUGH 06Z...PRIMARILY AT THE FAY/RWI TERMINALS.
ELSEWHERE...EXPECT NORTHWEST WINDS AT 5-10 KT THROUGH SUNRISE.
NORTHWEST WINDS WILL INCREASE TO 10-15 KT WITH GUSTS UP TO 25 KT
AFTER SUNRISE AND PERSIST INTO LATE THURSDAY AFT/EVE.
LOOKING AHEAD:
VFR CONDITIONS ARE EXPECTED TO PERSIST THURSDAY NIGHT INTO THE
WEEKEND...WITH BREEZY NW/NNW WINDS AGAIN ON FRIDAY. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
645 PM EST WED MAR 6 2013
.SYNOPSIS...
A POWERFUL LOW PRESSURE SYSTEM OVER COASTAL VIRGINIA WILL MOVE
OFFSHORE THROUGH TONIGHT. DRY HIGH PRESSURE WILL BUILD OVER THE
EASTERN SEABOARD THURSDAY THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 645 PM WEDNESDAY...
QUICK UPDATE TO CANCEL THE WIND ADVISORY AS WINDS HAVE DROPPPED OFF
CONSIDERABLY (LESS THAN 30KTS)IN MOST SPOTS. OTHERWISE...CENTRAL NC
WILL SEE ANOTHER HOUR OR TWO OF LIGHT RAIN OR SPRINKLES BEFORE THE
LAST PRECIP BAND PIVOTS OFF TO THE NORTHEAST.
PREVIOUS DISCUSSION...
THROUGH TONIGHT: IMPROVING WEATHER EXPECTED TONIGHT. LATEST SURFACE
MAP SHOWS THE STRONG SURFACE LOW NEAR THE MOUTH OF CHESAPEAKE BAY.
BANDS OF RAIN AND SNOW SHOWERS CONTINUE TO PIVOT AROUND THE LOW INTO
NORTHEAST NC... ALTHOUGH THUS FAR THIS AFTERNOON -- IN CONTRAST TO
THIS MORNING`S HRRR GUIDANCE -- THE SIGNIFICANT REFLECTIVITIES HAVE
HELD LARGELY NORTH AND EAST OF OUR FORECAST AREA. EXTRAPOLATION OF
EXISTING UPSTREAM PRECIP AND LOCAL WRF OUTPUT STILL SUPPORT PRECIP
WORKING ACROSS THE NORTHEAST CWA... ALONG AND NE OF A LINE FROM
OXFORD TO WILSON... FOR THE NEXT FEW HOURS. SURFACE WET BULBS ARE
GENERALLY ABOVE FREEZING IN THIS AREA... SO EXPECT A PTYPE OF MOSTLY
RAIN... ALTHOUGH HEAVIER BANDS MAY STILL MIX WITH A LITTLE
INCONSEQUENTIAL WET SNOW IN THE FAR NORTHEAST. THE LOW SWINGS
FARTHER OUT TO SEA THIS EVENING... LEAVING LITTLE MORE THAN PATCHY
SPRINKLES BEFORE THE PRECIP THREAT ENDS ENTIRELY BY MIDNIGHT.
REGARDING THE WINDS... WE`VE HAD NUMEROUS SITES ATTAIN PEAK GUSTS OF
40-46 MPH SO FAR TODAY WITH NEARLY ALL LOCATIONS SEEING 30 MPH GUSTS
OR GREATER. THE DEPARTURE OF THE COASTAL LOW AND SUBSEQUENT SLOW
SLACKENING OF THE MSLP GRADIENT AND GRADUAL DECREASE IN NEAR-SURFACE
MIXING WILL RESULT IN SLOWLY DECREASING WINDS AS WE GO THROUGH THE
EVENING. WILL LEAVE THE WIND ADVISORY IN PLACE UNTIL MIDNIGHT...
ALTHOUGH IT MAY NEED TO BE CANCELED A FEW HOURS EARLY. EXPECT
GRADUAL CLEARING SKIES FROM SW TO NORTHEAST AS WE DRY OUT IN THE
LOWEST FEW THOUSAND FEET. DESPITE DEW POINTS IN THE 20S THROUGH
TONIGHT... THE AIR SHOULD STAY JUST STIRRED ENOUGH NEAR THE GROUND
TO KEEP LOWS UP A BIT... 29-34.
FOR THURSDAY/THURSDAY NIGHT: WITH THE COLUMN DRYING OUT AND SINKING/
STABILIZING ALOFT... EXPECT QUITE A BIT OF SUNSHINE WITH PERHAPS
SOME FLAT AFTERNOON CUMULUS. SURFACE HIGH PRESSURE CENTERED OVER
ONTARIO AND THE UPPER MIDWEST/UPPER GREAT LAKES WILL EXTEND
SOUTHWARD WITH RIDGING BUILDING SLOWLY INTO NC FROM THE NW. WINDS
FROM THE NNW WILL NOT BE NEARLY AS STRONG AS THEY HAVE BEEN TODAY
BUT THE MSLP GRADIENT REMAINS TIGHT ENOUGH TO TRANSLATE INTO SURFACE
WINDS OF 10-15 KTS AND PERIODIC GUSTS TO 15-20 KTS BASED ON
PROJECTED WINDS IN THE UPPER PORTIONS OF THE MIXED LAYER. LOW LEVEL
THICKNESSES WILL BE AROUND 20-25 METERS BELOW NORMAL... SUGGESTING
HIGHS OF 51-58... OR ROUGHLY TWO CATEGORIES BELOW NORMAL. THE MID
LEVEL LOW NEAR LAKE SUPERIOR THIS MORNING WILL DROP TOWARD THE
SOUTHEAST OVER PA/DEL LATE THURSDAY NIGHT... HOWEVER THE LACK OF
MOISTURE AT ANY LEVEL AND NO OPPORTUNITY FOR AN MOISTURE TRANSPORT
INTO NC WITH LOW LEVEL FLOW FROM THE NNW WILL ALLOW SKIES TO STAY
GENERALLY CLEAR. LOWS 28-33 WITH 4-8 KTS OF WIND FROM THE NORTH.
-GIH
&&
.SHORT TERM /FRIDAY AND SUNDAY NIGHT/...
AS OF 250 PM WEDNESDAY...
AN OMEGA BLOCK WILL DEVELOP BY FRIDAY AS THE UPPER LOW OFF THE MID
ATLANTIC COAST CONTINUES TO WOBBLE SLOWLY TOWARD THE NORTH
ATLANTIC AND A CUTOFF LOW DEVELOPS OVER THE SOUTHWESTERN US.
MEANWHILE...A DISTURBANCE CURRENTLY MOVING INTO THE UPPER GREAT
LAKES AREA WILL BE DRAWN SOUTH ACROSS THE MID-ATLANTIC STATES AND
CLIP NORTHEASTERN NC EARLY FRIDAY. DEEP MOISTURE IS FORECAST TO BE
RATHER LIMITED...BUT ENHANCE CLOUD COVER OVER AT LEAST THE NORTHERN
COASTAL PLAIN SEEMS FAIRLY LIKELY WITH THE GLANCING BLOW OF THE VORT
MAX. FORECAST SOUNDINGS ALSO SHOW PERSISTENT BACKING OF THE LOW
LEVEL FLOW...WITH 10-15KT SURFACE WIND...SUGGESTING ANOTHER SURGE OF
COLD ADVECTION BEFORE HIGH PRESSURE BUILDS IN FROM THE GREAT LAKES
FRIDAY NIGHT. THUS...WILL KEEP HIGHS A GOOD 4-6 DEGREES BELOW MOST
GUIDANCE ON FRIDAY...49-55 NORTHEAST TO SOUTHWEST. LOWS FRIDAY
NIGHT IN THE UPPER 20S TO LOWER 30S.
RIDGING ALOFT WILL BUILD OVER HEAD SATURDAY THROUGH SUNDAY...WHILE
SURFACE HIGH PRESSURE SETTLES ALONG THE EAST COAST. THIS WILL LEAD
TO A MODERATING TREND IN TEMPS AS 850MB TEMPS APPROACH 10C AND LOW
LEVEL THICKNESSES RISE ABOVE 1350M BY SUNDAY.
HOWEVER...NORTHEASTERLY LOW LEVEL FLOW IS FORECAST
TO CONTINUE SATURDAY...SO THE WARMING ALOFT MAY NOT BE COMPLETELY
REALIZED FOR YET ANOTHER DAY. THE MORE NOTICEABLE WARMUP WILL BE
FELT IN THE NORTHEAST CWA ON SATURDAY...WITH HIGHS RANGING FROM THE
MID 50S NORTHEAST TO AROUND 60 SOUTHWEST. THE SURFACE HIGH IS
FORECAST TO SHIFT OFFSHORE BY SUNDAY...AND IF THIS OCCURS...THEN
WEAK RETURN FLOW WOULD DEVELOP AND HELP PUSH HIGHS INTO THE MID
60S. DRY CONDITIONS WILL PERSIST BENEATH THE RIDGE.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 250 PM WEDNESDAY...
THE OMEGA BLOCK OVER THE CONUS IS FORECAST TO WEAKEN BY
MONDAY..ALLOWING AN UPPER LOW OVER THE SOUTHWESTERN US TO EJECT
EASTWARD ACROSS THE SOUTHERN PLAINS AND DEAMPLIFY AS IT LIFTS TOWARD
THE MIDWEST STATES . SOUTHERLY RETURN FLOW AHEAD OF THE SYSTEM
SHOULD PUSH TEMPS WELL ABOVE NORMAL MONDAY WITH LOW LEVEL THICKNESSES
PROGGED TO APPROACH 1360M. BASED ON THIS...UPPER 60S SEEM LIKELY
AND LOWER 70S POSSIBLE UNLESS CLOUD COVER IS MORE ROBUST THAN
FORECAST. AS THE UPPER TROUGH AND PRIMARY SURFACE LOW LIFT ACROSS
THE MIDWEST AND OH VALLEY...THE ATTENDANT COLD FRONT IS EXPECTED TO
MOVE CROSS THE MOUNTAINS MONDAY NIGHT/TUESDAY. THE GFS AND ECMWF
HAVE WAVERED BACK AND FORTH A BIT REGARDING THE EXACT TIMING OF THE
FRONTAL PASSAGE AND SENSIBLE WEATHER...BUT THEIR SOLUTIONS ARE
GENERALLY WITHIN 12 HOURS OF EACH OTHER. HOWEVER...THERE ARE STILL
ENOUGH DIFFERENCES IN THE MASS FIELDS TO KEEP POPS BELOW 50 PERCENT
AT THIS TIME. SHOULD ALSO NOTE THAT AS WE MOVE FURTHER INTO
MARCH...THIS TYPE OF PATTERN WILL BRING A BETTER CHANCE OF
THUNDERSTORMS ACCOMPANYING THE COLD FRONT...BUT WE WILL HOLD OFF ON
INCLUDING THUNDER IN THE FORECAST UNTIL TIMING OF THE SYSTEM AND
MOISTURE RETURN ARE MORE CERTAIN.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1230 PM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PERSIST AT INT/GSO/FAY WELL INTO
WEDNESDAY. RDU/RWI WILL REMAIN CLOSER TO THE LOW CLOUD SHIELD (MVFR
TO HIGH-END IFR CIGS) ASSOCIATED WITH THE STRONG STORM CENTERED OVER
THE SE COAST OF VA... SO A PERIOD OF MVFR CIGS AND BRIEF MVFR VSBYS
WITHIN LIGHT RAIN SHOWERS (POSSIBLY MIXED WITH WET SNOW) ARE
POSSIBLE THIS AFTERNOON UNTIL 23Z-01Z. AS THIS STORM SYSTEM HEADS
OFF THE COAST THIS EVENING... SKIES WILL CLEAR OUT SW TO NE. STRONG
WINDS COMING FROM THE WEST AND NW WILL REMAIN AN AVIATION HAZARD
THROUGH EARLY TO MID EVENING... PRESENTING A SIGNIFICANT CROSSWIND
PRIMARILY AT GSO/RDU/RWI/FAY. SUSTAINED WINDS OF 15-25 KTS AND GUSTS
TO 30-38 KTS ARE EXPECTED THROUGH 22Z... THEN NW WINDS WILL BE
DIMINISHING THROUGH THE EVENING AS THEY BECOME NORTHERLY. UNLIMITED
SKIES AND NORTH WINDS 7-12 KTS ARE EXPECTED AFTER SUNRISE THURSDAY.
LOOKING BEYOND 18Z THURSDAY... VFR CONDITIONS WILL DOMINATE THROUGH
EARLY FRIDAY. BRIEF MVFR CIGS ARE POSSIBLE FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS LOW PRESSURE MOVES BY TO OUR NORTHEAST. THEN AS A
STORM SYSTEM APPROACHES FROM THE WEST... IFR CIGS ARE POSSIBLE EARLY
MONDAY MORNING... LIFTING TO VFR BY MONDAY AFTERNOON.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL/HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
901 PM CST WED MAR 6 2013
.DISCUSSION...
CLOUDS AND TEMPERATURES CONTINUE TO BE THE CHALLENGE THIS EVENING.
THE STRATUS OVER THE RED RIVER VALLEY THIS AFTERNOON HAS DRIFTED
WESTWARD...ALTHOUGH THERE HAS BEEN SOME CIRRUS MOVING IN ON TOP OF
IT INTO THE CENTRAL CWA. CLEAR SKIES IN SOME LOCATIONS HAVE
ALLOWED A STEEP DROP...WITH HALLOCK ALREADY DROPPING TO -2 F.
THINK THAT THERE SHOULD BE A BIT OF MODERATION AS CIRRUS CONTINUES
TO MOVE IN. ON THE OTHER HAND...THE CIRRUS WILL NOT BE NEARLY AS
GOOD AT KEEPING RADIATION IN AS THE STRATUS WOULD BE. THE RAP
AND HRRR HAVE MOST OF THE STRATUS/HIGH RH VALUES STAYING FROM
NORTH CENTRAL ND INTO THE SOUTHERN RED RIVER VALLEY. GIVEN THE
INCREASING SOUTHEASTERLY WINDS...THIS SEEMS REASONABLE.
THUS...LOWERED LOWS A BIT IN THE CENTRAL CWA THAT WILL PROBABLY
NOT SEE THE LOW LEVEL CLOUDS HANGING AROUND AND RAISED THEM A BIT
IN THE FAR WEST WHERE THERE SHOULD STILL BE SOME STRATUS. RAP
SEEMED TO HAVE A DECENT HANDLE ON CURRENT TEMPS FOLLOWED ITS CURVE
AS A FIRST GUESS AT THIS POINT.
&&
.AVIATION...
MVFR STRATUS HAS MOVED EAST OF KGFK AND KFAR...WITH CIRRUS MAINLY
OVER ALL BUT KDVL. THINK THAT THE STRATUS SHOULD STAY MAINLY OVER
THE WESTERN FORECAST AREA THROUGH EARLY MORNING BEFORE BEGINNING
TO BE PUSHED BACK TO THE EAST AS A SFC TROUGH AXIS MOVES INTO THE
REGION. THERE COULD BE A BRIEF RETURN TO MVFR CEILINGS FOR KGFK
AND KFAR DURING MID DAY TOMORROW. SOUTHEASTERLY WINDS WILL PICK UP
INTO THE 15 TO 20 KT RANGE WITH GUSTS TO 25 KTS POSSIBLE BY 15Z OR
SO.
&&
.PREV DISCUSSION... /ISSUED 220 PM CST WED MAR 6 2013/
SHORT TERM...
THE MAIN CHALLENGE THIS AFTERNOON WILL BE ACCUMULATING SNOW
CHANCES FRIDAY NIGHT INTO SATURDAY. MODELS ARE IN DECENT
AGREEMENT...BUT DIFFER WITH RESPECT TO A NORTHERN SHORTWAVE FRIDAY
NIGHT AND SAT...AND THIS WILL MAKE A BIG DIFFERENCES WITH WEEKEND
SNOW POTENTIAL. IT APPEARS THE SOUTHERN VALLEY WOULD HAVE THE
BIGGEST THREAT FOR SOME SNOW ACCUMULATION FRI NIGHT AND SAT. THE
NAM IS THE FARTHEST NORTH...WITH THE GEM/ECMWF NOT FAR BEHIND...SO WILL
FOLLOW A NAM/GEM/ECMWF BLEND.
FOR TONIGHT...CLOUDS MAY REMAIN IN THE VALLEY AND COULD RE-DEVELOP
ONCE RETURN FLOW BEGINS. TEMPS SHOULD REMAIN FAIRLY MILD IN ALL
BUT THE FAR EAST...WHERE SOME CLEARING AND LIGHTER WINDS SHOULD
REMAIN THROUGH ABOUT 06Z THU.
ON THU...SOUTHEAST WINDS WILL INCREASE WITH 25-30KT TO MIX IN THE
VALLEY BY AFTERNOON. THEREFORE...IT SHOULD BECOME BRISK WITH GUSTS
OVER 25 MPH AT TIMES IN THE VALLEY...AND PERHAPS SOME DRIFTING
SNOW OR EVEN MINOR BLOWING SNOW IN OPEN AREAS. THERE WILL ALSO BE A
CHANCE FOR SOME LIGHT SNOW MAINLY IN NORTHEAST ND BY AFTERNOON
CLOSER TO SATURATION AND WEAK ISENTROPIC LIFT.
FOR FRI...EXPECT A DRY DAY WITH TEMPS WARMING ABOVE NORMAL IN MOST
AREAS WITH WESTERLY SFC FLOW. TEMPS MAY GET EVEN WARMER IF IT
REMAINS MOSTLY SUNNY...SO SOMETHING TO MONITOR.
FOR FRI NIGHT AND SAT...A NORTHERN STREAM SHORTWAVE WILL INTERACT
WITH SW FLOW ALOFT AND A FRONTAL BOUNDARY NEAR THE SOUTHERN
FORECAST AREA. THE BEST CHANCE FOR ACCUMULATING SNOW WILL OCCUR IN
THE SOUTHERN 1/3 OF THE FORECAST AREA...WITH PWATS OVER 0.5 INCHES
AND STRONG MOISTURE ADVECTION. THERE WILL BE A CHANCE OF LIGHT
SNOW IN ALL AREAS...AND MODEL TRENDS NORTH OR SOUTH HAVE TO BE
MONITORED CLOSELY. IF THE TRACK OF THE LOW SHIFTS SLIGHTLY
NORTH...THEN THERE IS THE POTENTIAL FOR ACCUMULATING SNOW ACROSS A
GOOD PORTION OF THE AREA. IN ADDITION...CAN/T RULE OUT SOME MIXED
PRECIPITATION IN THE SOUTH DEPENDING ON HOW WARM MID LEVEL TEMPS
GET...BUT FOR NOW SOUNDINGS INDICATE ALL SNOW SO WILL LEAVE OUT
MENTION OF FREEZING RAIN.
LONG TERM (SAT NIGHT TO WEDNESDAY)...
MODELS CONTINUE TO BE INCONSISTENT WITH RUN TO RUN SOLNS AND
THEREFORE CONFIDENCE DECREASES INTO THE MIDDLE OF NEXT WEEK WITH
RESPECT TO TEMPS AND PRECIP. BY SATURDAY NIGHT A PROGRESSIVE UPPER
WAVE IN THE NORTHERN STREAM PUSHES EAST INTO ONTARIO ENDING CHC -SN
ACROSS THE EAST. NW FLOW AT 500MB WILL ESCORT SFC HIGH INTO THE AREA
SUNDAY AND MONDAY WITH A CLIPPER TYPE SYSTEM PROGGED FOR TUESDAY.
TEMPS WILL BE NEAR TO BELOW NORMAL IN THE VALLEY GIVEN DEEP SNOW
PACK IN CONTRAST TREED AREAS OF MN RESPONDING TO MARCH SOLAR
EFFICIENTLY AND COULD SEE HIGHER TEMPS THAN FORECAST IF SKIES REMAIN
CLEAR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
423 PM EST TUE MAR 5 2013
.SYNOPSIS...
A WINTER STORM WILL AFFECT THE AREA TONIGHT AND EARLY WEDNESDAY.
HIGH PRESSURE WILL BUILD ACROSS THE REGION LATE THIS
WEEK...LASTING INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AN UPPER LOW IS DIVING SOUTHEASTWARD OUT OF THE NORTHERN PLAINS
AND INTO THE TENNESSEE VALLEY THIS EVENING. A SURFACE LOW
DEVELOPING OVER KENTUCKY...OUT AHEAD OF THE UPPER LOW WILL DEEPEN
AND PIVOT NORTHEASTWARD OVER THE OHIO VALLEY AS THE UPPER LOW
SLIDES BY TO THE SOUTH TONIGHT. PRECIPITATION IS ALREADY SPREADING
NORTHWARD ACROSS THE FORECAST AREA AHEAD OF THE INTENSIFYING
SURFACE LOW. PRECIPITATION WILL FALL AS RAIN ACROSS THE AREA INTO
THE EARLY EVENING...AS WARM AIR IS DRAWN NORTH AND WEST INTO THE
LOW LEVELS AROUND THE LOW.
THE FORECAST FOR LATER THIS EVENING BECOMES COMPLICATED...AS COLD
AIR BEGINS TO WORK ITS WAY BACK INTO THE LOW. THIS PROCESS WILL BE
TWOFOLD. LOW LEVEL COLD ADVECTION WILL ALLOW FOR COLDER AIR TO
WRAP INTO THE SURFACE LOW. AT THE SAME TIME...ABUNDANT VERTICAL
MOTION WILL PROVIDE FOR DYNAMIC COOLING FROM THE MIDDLE
LEVELS...PROPAGATING TO THE SURFACE. MODELS ARE IN AGREEMENT ON
THE STRONG VERTICAL MOTION ASSOCIATED WITH THIS SYSTEM THIS
EVENING ACROSS OUR AREA. HOWEVER...THERE ARE CRITICAL DIFFERENCES
IN HOW THE MODELS ARE HANDLING THE BATTLE BETWEEN DYNAMIC
COOLING...AND WARM AIR BEING PULLED IN AROUND THE LOW. BASED ON
HOW STRONG ASCENT IS AS HEAVIER PRECIPITATION MOVES IN THIS
EVENING...THIS FORECAST PACKAGE WENT WITH A MODERATELY FAST
CHANGEOVER TO SNOW TO BEGIN IN THE WESTERN ZONES AROUND 7
PM...SPREADING EAST THROUGH THE DAYTON/CINCY AREAS BY 9 PM...THEN
COLUMBUS BY 10 OR 11 PM. IF THE DYNAMIC COOLING PROCESS IS
STRONGER THAN THIS FORECAST IS HINTING AT...THEN THIS CHANGEOVER
WILL OCCUR SOONER...WITH THE RESULT BEING HIGHER SNOW TOTALS. OF
COURSE...IF ADDITIONAL WARMER AIR IS DRAW INTO THE SYSTEM...LIKE
THE RAP SUGGESTS THEN MORE RAIN WILL FALL INITIALLY. THE RAP
SOLUTION HAS BEEN ON THE WARM SIDE TODAY...THEREFORE AM LEANING
TOWARD THE COLDER SOLUTIONS.
ANY SNOW THAT OCCURS JUST AFTER THE CHANGEOVER WILL BE A
HEAVY...WET SNOW. THE BOTTOM LINE IS THAT THE MODELS LOOK AS IF
THEY ARE PICKING UP ON THE STRONGER LIFT BASED ON QPF AMOUNTS
RISING OVER RECENT RUNS. THIS MEANS A POTENTIAL FOR HIGHER STORM
TOTALS FOR OUR AREA. TOTAL SNOWFALL NUMBERS WERE THEREFORE TWEAKED
SLIGHTLY HIGHER...WITH THE MAXIMUM BEING AROUND 8 INCHES STORM
TOTAL ACROSS THE NORTHWESTERN ZONES. SOME OF THE SOUTHWESTERN
ZONES...WHERE A TRANSITION WILL OCCUR FIRST...MAY RECEIVE UP TO 4
INCHES OF SNOW. THE TRICKIEST SNOWFALL TOTAL FORECAST LIED WHERE
THE CENTER OF THE SURFACE LOW IS EXPECTED TO SPIN FOR A FEW HOURS
TONIGHT...ACROSS THE SCIOTO VALLEY. THERE...SNOWFALL AMOUNTS COULD
VARY QUITE A BIT...NOT ONLY DUE TO THE DELAYED CHANGEOVER DUE TO
SOME WARMER AIR...BUT THE LACK OF HEAVIER QPF UNDERNEATH THE LOW`S
CENTER LATE TONIGHT.
EXPANDED THE WINTER STORM WARNING TO INCLUDE SOME OUR OUR NORTHERN
KENTUCKY ZONES THAT ARE NOW EXPECTED TO REACH OUR 12 HOUR
CRITERIA OF 4 INCHES OF SNOW TONIGHT. DID DELAY THE START OF ALL
WARNINGS/ADVISORY EXCEPT ACROSS THE EXTREME NORTH...SINCE THAT
WARNING WAS ALREADY IN EFFECT AT THE TIME OF THE FORECAST PACKAGE
ISSUANCE.
SNOW WILL CONTINUE THROUGHOUT THE EARLY PRE-DAWN HOURS AS THE SURFACE
LOW SPINS ACROSS SOUTHEASTERN OHIO.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
THE UPPER LOW WILL QUICKLY SHIFT TOWARD THE MID ATLANTIC STATES
WEDNESDAY MORNING AS A SECONDARY SURFACE LOW DEVELOPS CLOSER TO
THE EASTERN SEABOARD. THIS ENERGY TRANSFER EASTWARD...AND AWAY
FROM OUR AREA WILL BRING A RAPID END TO FORCING SUPPORTING STEADY
SNOW IN OUR AREA. SNOW WILL TAPER OFF QUICKLY AROUND SUNRISE WITH
ONLY SOME LIGHTER SNOW SHOWERS EXPECTED DURING THE DAY.
NORTHERLY FLOW BEHIND THE DEPARTING STORM SYSTEM AND RIDGING
ACROSS THE NORTHERN PLAINS WILL KEEP A CHANCE FOR LIGHT SNOW OR
FLURRIES IN OUR AREA THROUGH WEDNESDAY NIGHT AND INTO THE DAY
THURSDAY. TEMPERATURES DURING THIS TIME PERIOD WILL REMAIN BELOW
NORMAL. LOW LEVEL MOISTURE...AND ASSOCIATED CLOUD COVER WILL
FINALLY BEGIN TO GIVE WAY TO DRIER CONDITIONS THURSDAY NIGHT...AS
THE RIDGE BUILDS ACROSS THE OHIO VALLEY. TEMPERATURES WILL LIKELY
BOTTOM OUT THURSDAY NIGHT IN THE UPPER TEENS TO LOW 20S UNDER
PARTLY CLOUDY SKIES.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AFTER A PLEASANT AND GENERALLY MILD WEEKEND...WITH GOOD MODEL
AGREEMENT...THERE IS CONSIDERABLE UNCERTAINTY ON A WEATHER SYSTEM
MOVING INTO THE REGION EARLY NEXT WEEK.
THE WEEKEND WILL BEGIN WITH A MID LEVEL TROUGH AXIS EXTENDING FROM
THE GULF OF MEXICO TO NORTHERN INDIANA. WARM ADVECTION WILL BE
UNDERWAY ALOFT...AND SHOULD BEGIN AT THE SURFACE AS WELL (AS WINDS
TAKE A SOUTHERLY COMPONENT). THIS PATTERN WILL GENERALLY CONTINUE
INTO SUNDAY...AS THE RIDGE AXIS MOVES EAST. WITH QUITE A BIT OF SUN
ON SATURDAY (PERHAPS JUST SOME LOW CLOUDS THAT ARE SLOW TO MOVE OUT
OF THE NORTHEASTERN CWA)...TEMPERATURES WILL RISE ABOVE NORMAL BY
ABOUT 5 DEGREES.
THE RIDGE WILL CONTINUE TO DOMINATE THE WEATHER ON SUNDAY...BUT AS
INFLUENCE FROM THE DEVELOPING WEATHER SYSTEM IN THE WESTERN STATES
BEGINS TO COMPLICATE THE FORECAST...SOME UNCERTAINTY WILL BEGIN TO
SET IN. MOISTURE WILL BEGIN TO ADVECT IN ALOFT...LEADING TO HIGH
CLOUDS THICKENING THROUGH THE DAY. DESPITE THIS...SURFACE WARM
ADVECTION WILL BE STRENGTHENING...LEADING TO EVEN WARMER TEMPS ON
SUNDAY.
BEYOND SUNDAY...A VERY HIGH AMOUNT OF UNCERTAINTY EXISTS IN THE
FORECAST. IT APPEARS CERTAIN THAT A WESTERN TROUGH WILL EJECT INTO
THE EASTERN STATES...AS SURFACE LOW PRESSURE DEVELOPS AND MOVES
THROUGH OR NEAR THE OHIO VALLEY. HOWEVER...THERE IS VERY LOW
CONFIDENCE IN THE TIMING OF THIS SYSTEM...AS WELL AS IN THE
PLACEMENT OF THE SURFACE LOW. DETERMINISTIC MODELS (12Z GFS VS 12Z
CMC VS 00Z ECMWF) ARE AS MUCH AS A DAY AND A HALF OFF IN
TIMING...WITH THE SURFACE LOW POSSIBLY GOING NORTH OR SOUTH OF THE
AREA. SO...AT THIS TIME...THE FORECAST WILL REMAIN VERY GENERAL.
ALTHOUGH IT IS FRUSTRATING TO GO NO HIGHER THAN 30 POPS WHEN RAIN
APPEARS A VIRTUAL CERTAINTY AT SOME POINT IN THE SUNDAY NIGHT
THROUGH TUESDAY TIME FRAME...THE TIMING DIFFERENCES ARE TOO GREAT TO
GO HIGHER.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
LIGHT PCPN IS CONTINUING ACROSS THE AREA EARLY THIS AFTERNOON.
STILL SEEING A LITTLE BIT OF SLEET AND SNOW MIXING IN ACROSS
CENTRAL OHIO...BUT THINK WE SHOULD BE JUST ABOUT OVER TO ALL FOR
THE REST OF THE AFTERNOON. A STRENGTHENING LOW PRESSURE SYSTEM WILL
PIVOT ACROSS THE AREA OVERNIGHT. AHEAD OF THIS...EXPECT MORE
WIDESPREAD/HEAVIER PCPN TO OVERSPREAD THE AREA FROM THE SOUTHWEST
THROUGH LATE AFTERNOON/EARLY EVENING. BEST FORCING WILL PIVOT UP
THROUGH THE AREA IN THE 00Z TO 03Z TIME FRAME. PCPN WILL START OFF
AS ALL RAIN...BUT SHOULD TRANSITION OVER TO SNOW FROM WEST TO EAST
ACROSS THE AREA THIS EVENING. THE EXACT TIME OF CHANGEOVER IS
STILL UNCERTAIN AS THERE WILL BE SOME WARM LOW LEVEL AIR BEING
PULLED IN FROM THE SOUTHEAST AHEAD OF THE LOW...WITH COLDER AIR
WRAPPING IN ON THE BACKSIDE OF IT. THIS WILL BE FURTHER
COMPLICATED BY THE POSSIBILITY OF SOME DYNAMIC COOLING GIVEN THE
INITIAL STRENGTH OF LIFT IN THE ATMOSPHERE. BEST GUESS IS A
CHANGEOVER AT KDAY AROUND 00Z...KCVG/KLUK 01Z...KILN 02Z AND
KCMH/KLCK 04Z. ONCE IT DOES CHANGE OVER...EXPECT A WET...HEAVY
SNOW FOR SEVERAL HOURS WITH IFR/LIFR VSBYS AND CIGS. SNOW WILL
THEN LINGER THROUGH MUCH OF THE NIGHT AS THE SURFACE LOW WOBBLES
ACROSS SOUTHERN OHIO INTO WEDNESDAY MORNING.
OUTLOOK...MVFR CEILINGS MAY LINGER INTO THURSDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR OHZ054>056-
060>065-070>072-077>080.
WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR OHZ026-034-
035-042>046-051>053.
WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR OHZ073-
074-081-082-088.
KY...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR KYZ089>093.
WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR
KYZ094>100.
IN...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR INZ050-058-
059-066-073>075-080.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...HATZOS
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1031 AM EST TUE MAR 5 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK EAST THROUGH KENTUCKY TODAY. AN UPPER
LEVEL LOW WILL DIVE SOUTHEAST FROM THE NORTHERN PLAINS AND
STRENGTHEN AS IT CUTS THROUGH THE SOUTHERN OHIO VALLEY TONIGHT.
THESE LOW PRESSURE SYSTEMS WILL MOVE TO THE EAST COAST BY
WEDNESDAY MORNING AS HIGH PRESSURE BUILDS OVER THE MIDWEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN AREA OF SHOWERS IS SPREADING UP ACROSS CENTRAL OHIO ASSOCIATED
WITH THE INITIAL SHOT OF ISENTROPIC LIFT. NOT MUCH OF THIS HAS BEEN
REACHING THE GROUND SO FAR..BUT IT DOES APPEAR TO FILLING IN SO
WILL NUDGE UP POPS ACROSS NORTHEASTERN AREAS THROUGH EARLY
AFTERNOON. PCPN BEHIND THIS IS MORE SPOTTY ACROSS NORTHERN
KENTUCKY AND SOUTHEAST INDIANA...BUT THIS TOO SHOULD FILL IN
THROUGH THIS AFTERNOON AS GOOD LOW LEVEL CONVERGENCE DEVELOPS
AHEAD OF THE APPROACHING LOW. COULD STILL SEE SOME SNOW MIXED WITH
RAIN ACROSS THE NORTH THROUGH LATE MORNING...BUT WE SHOULD WARM UP
ENOUGH BY EARLY THIS AFTERNOON TO PUSH PTYPE OVER TO ALL RAIN.
LATEST MODELS ARE A BIT WARMER AND THIS MAY DELAY ONSET OF
CHANGEOVER BACK TO SNOW A FEW HOURS. WILL ADJUST THE WEATHER GRIDS
ACCORDINGLY AND PUSH BACK START TIME FOR THE WSW ACROSS MUCH OF
THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
RAPID CHANGEOVER TO SNOW THIS EVENING WILL BE COMBINED WITH
MODERATE PRECIPITATION RATES DUE TO THE AFOREMENTIONED FRONT.
UPPER LOW UNDERCUTTING THE SURFACE LOW WILL HAVE THE LIONS SHARE
OF SNOW OCCUR THIS EVENING AND TAPER OFF OVERNIGHT WITH LIGHTER
ACCUMULATIONS EXPECTED THROUGH DAYBREAK. HAVE ADDED CINCY METRO
AREA TO THE WARNING AS 3-4 INCHES OF SNOW REMAINS POSSIBLE IN THE
EVENING AND OVERNIGHT TONIGHT...ESPECIALLY IF EITHER OF THESE LOWS
EXHIBIT A QUICKER MOVEMENT.
LINGERING LIGHT SNOW MAY SEE SOME ADDITIONAL ACCUMULATIONS EARLY
WEDNESDAY MORNING BUT MOST OF THE SNOW SHOULD BE OVER BY NOON.
LOWERED THE TEMPERATURES A BIT FOR WEDNESDAY NIGHT AND THURSDAY
WITH THE EXPECTED SNOW COVER ALLOWING A GOOD DROP IN TEMPS AND
LIMITING DAYTIME RISES. HIGH PRESSURE WILL BUILD IN TO THE WEST ON
THURSDAY AND CLOUD COVER WILL EXHIBIT AN EROSION FROM WEST TO
EAST...PARTICULARLY IN THE LATE DAY AS 850 TEMPS WARM SIGNIFICANTLY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MID/UPPER LEVEL RIDGE TO BUILD INTO THE GREAT LAKES/OHIO VALLEY THRU
THE END OF THE WEEK INTO NEXT WEEKEND. THIS FEATURE WILL RESULT IN
DRY WEATHER CONDITIONS WITH A SIGNIFICANT WARMUP. HIGHS ON THURSDAY
WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH. FRIDAYS
HIGHS WILL CLOSER TO NORMAL...RANGING FROM THE LOWER/MIDDLE 40S
NORTH TO THE LOWER 50S SOUTH. SATURDAYS HIGHS LOOK TO BE 6 TO 10
DEGREES ABOVE NORMAL...RANGING FROM THE UPPER 40S NORTH TO THE UPPER
50S SOUTH.
S/W ENERGY PASSING THRU SRN CANADA WILL FLATTEN THE FAR NRN PORTION
OF THE RIDGE WITH A WEAK SFC FRONT DROPPING SOUTH INTO THE GREAT
LAKES SAT NIGHT/SUNDAY. THIS FRONT LOOKS TO LOSE ITS IDENTITY WITH
LACK OF UPPER SUPPORT AND LIMITED MOISTURE. THEREFORE...WILL LIMIT
POPS TO SLIGHT CHC OF RAIN SHOWERS ACRS THE NORTH SUNDAY. SUNDAYS
HIGHS WILL CONTINUE TO BE ABOUT 10 DEGREES ABOVE NORMAL...RANGING
FROM NEAR 50 NW TO NEAR 60 SE.
A BETTER CHANCE FOR RAIN LOOKS TO OCCUR MONDAY AFTN AS MSTR
INCREASES AS THE FLOW BACKS HAD OF A SYSTEM MOVING OUT OF THE
CENTRAL PLAINS. WILL SPREAD CHANCE POPS ACRS THE FA FROM THE WEST.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
INITIAL SHOT OF RAIN AHEAD OF THE LOW CENTER IN WRN KY LOOKS LIKE
IT WILL SLIP MAINLY S OF THE TAF SITES INITIALLY THIS MORNING.
THE 06Z NAM HAS PICKED UP NICELY ON THIS. STILL PUT IN A TEMPO
GROUP FOR CVG/LUK/ILN FOR A CHC OF MVFR VSBYS/CIGS AS THE FEATURE
SLIPS E.
SFC LOW WILL DEEPEN AS IT WORKS E TODAY. ADDITIONAL RAIN WILL
DEVELOP LATER THIS MORNING AND WILL SPREAD NWD. PCPN TYPE TODAY
SHOULD BE RAIN ACROSS ALL OF THE TAFS FOR MUCH OF THE DAY. CIGS
WILL LOWER TO MVFR AS THE PCPN SHIELD WORKS IN.
FOCUS THEN SHIFTS TO THE TIMING OF THE CHANGE OVER TO SNOW. 06Z
NAM AND THE 10Z RUC ARE INDICATING THAT THE CHANGE OVER MIGHT BE A
LITTLE SLOWER AND THE WARM AIR HANGS IN A LITTLE LONGER. BACKED
OFF ON THE CHANGE OVER BY AN HOUR OR SO...NOW 00-03Z IN THE W AND
03Z-06Z IN THE E. THE PCPN RATES WILL BE HEAVY AS THE CHANGE OVER
AS THE CHANGE OVER WILL BE DURING THE PERIOD OF MOST INTENSE
UPWARD LIFT. EXPECT A PERIOD OF MODERATE TO HEAVY SNOW AFTER THE
CHANGE OVER WITH LIFR CONDITIONS.
OUTLOOK...MVFR/IFR CONDITIONS WILL CONTINUE INTO WEDNESDAY. MVFR
CEILINGS MAY LINGER INTO THURSDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST
WEDNESDAY FOR OHZ054>056-060>065-070>072-077>080.
WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR OHZ026-034-
035-042>046-051>053.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR OHZ073-074-081-082-088.
KY...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST
WEDNESDAY FOR KYZ091>093.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR KYZ089-090-094>100.
IN...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST
WEDNESDAY FOR INZ050-058-059-066-073-074.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR INZ075-080.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...JGL
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
642 AM EST TUE MAR 5 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK EAST THROUGH KENTUCKY TODAY. AN UPPER
LEVEL LOW WILL DIVE SOUTHEAST FROM THE NORTHERN PLAINS AND
STRENGTHEN AS IT CUTS THROUGH THE SOUTHERN OHIO VALLEY TONIGHT.
THESE LOW PRESSURE SYSTEMS WILL MOVE TO THE EAST COAST BY
WEDNESDAY MORNING AS HIGH PRESSURE BUILDS OVER THE MIDWEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE TRIED TO ADD MORE DETAIL TO THE FORECAST THIS MORNING AS RAIN
WILL DOMINATE TODAY AND BE MODERATE AT TIMES IN THE AFTERNOON. AS
THE UPPER LOW CUTS TO THE SOUTH...THERE WILL BE A VERY QUICK
CHANGE FROM MODERATE RAIN TO MODERATE SNOW AND SNOWFALL RATES
SHOULD EXCEED AN INCH PER HOUR. THE TIGHT POSITION OF THE SURFACE
LOW IN SOUTHWEST OHIO FOUND ANYWHERE FROM CINCINNATI TO
HILLSBORO TO CHILLICOTHE ADDS A LAYER OF COMPLEXITY THAT IS
DIFFICULT TO IMPART IN THE FORECAST. NORTH AND WEST OF METRO
DAYTON WILL SEE THE RAPID CHANGEOVER IN THE LATER
AFTERNOON...WHILE THE REST OF THE OHIO VALLEY WILL SEE THE
CHANGEOVER EARLY IN THE EVENING. THE WORST OF THE SNOWFALL WILL BE
OCCURRING THIS EVENING. MODERATE SNOW WILL TAPER OFF AFTER
MIDNIGHT BUT ADDITIONAL ACCUMULATIONS WILL BE POSSIBLE THROUGH
EARLY WEDNESDAY.
UPPER LEVEL RIDGE IS BREAKING DOWN AS SURFACE LOW MOVES NORTHEAST
THROUGH KENTUCKY TODAY. WARM AIR AT THE SURFACE WILL BE PULLED IN
WITH THIS LOW AS RAIN OVERSPREADS THE OHIO VALLEY AND CWA FROM THE
SOUTHWEST. THICKNESSES IN THE MIAMI VALLEY AND NORTHWEST OF DAYTON
WILL SUPPORT SOME SNOW MIXING IN THIS AFTERNOON WITH A CHANGEOVER
TO SNOW BY EVENING. PRECIPITATION WILL BE MODERATE AT TIMES AS THE
SURFACE LOW GETS ENERGY PULLED NORTHWEST AND A FRONT DEVELOPS.
RESULTING FRONT WILL EXTEND NORTHWEST FROM CINCY AREA TO
INDIANAPOLIS. SURFACE TEMPERATURES WILL REACH THE MID 30S
NORTH...UPPER 30S SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
RAPID CHANGEOVER TO SNOW THIS EVENING WILL BE COMBINED WITH
MODERATE PRECIPITATION RATES DUE TO THE AFOREMENTIONED FRONT.
UPPER LOW UNDERCUTTING THE SURFACE LOW WILL HAVE THE LIONS SHARE
OF SNOW OCCUR THIS EVENING AND TAPER OFF OVERNIGHT WITH LIGHTER
ACCUMULATIONS EXPECTED THROUGH DAYBREAK. HAVE ADDED CINCY METRO
AREA TO THE WARNING AS 3-4 INCHES OF SNOW REMAINS POSSIBLE IN THE
EVENING AND OVERNIGHT TONIGHT...ESPECIALLY IF EITHER OF THESE LOWS
EXHIBIT A QUICKER MOVEMENT.
LINGERING LIGHT SNOW MAY SEE SOME ADDITIONAL ACCUMULATIONS EARLY
WEDNESDAY MORNING BUT MOST OF THE SNOW SHOULD BE OVER BY NOON.
LOWERED THE TEMPERATURES A BIT FOR WEDNESDAY NIGHT AND THURSDAY
WITH THE EXPECTED SNOW COVER ALLOWING A GOOD DROP IN TEMPS AND
LIMITING DAYTIME RISES. HIGH PRESSURE WILL BUILD IN TO THE WEST ON
THURSDAY AND CLOUD COVER WILL EXHIBIT AN EROSION FROM WEST TO
EAST...PARTICULARLY IN THE LATE DAY AS 850 TEMPS WARM SIGNIFICANTLY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MID/UPPER LEVEL RIDGE TO BUILD INTO THE GREAT LAKES/OHIO VALLEY THRU
THE END OF THE WEEK INTO NEXT WEEKEND. THIS FEATURE WILL RESULT IN
DRY WEATHER CONDITIONS WITH A SIGNIFICANT WARMUP. HIGHS ON THURSDAY
WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH. FRIDAYS
HIGHS WILL CLOSER TO NORMAL...RANGING FROM THE LOWER/MIDDLE 40S
NORTH TO THE LOWER 50S SOUTH. SATURDAYS HIGHS LOOK TO BE 6 TO 10
DEGREES ABOVE NORMAL...RANGING FROM THE UPPER 40S NORTH TO THE UPPER
50S SOUTH.
S/W ENERGY PASSING THRU SRN CANADA WILL FLATTEN THE FAR NRN PORTION
OF THE RIDGE WITH A WEAK SFC FRONT DROPPING SOUTH INTO THE GREAT
LAKES SAT NIGHT/SUNDAY. THIS FRONT LOOKS TO LOSE ITS IDENTITY WITH
LACK OF UPPER SUPPORT AND LIMITED MOISTURE. THEREFORE...WILL LIMIT
POPS TO SLIGHT CHC OF RAIN SHOWERS ACRS THE NORTH SUNDAY. SUNDAYS
HIGHS WILL CONTINUE TO BE ABOUT 10 DEGREES ABOVE NORMAL...RANGING
FROM NEAR 50 NW TO NEAR 60 SE.
A BETTER CHANCE FOR RAIN LOOKS TO OCCUR MONDAY AFTN AS MSTR
INCREASES AS THE FLOW BACKS HAD OF A SYSTEM MOVING OUT OF THE
CENTRAL PLAINS. WILL SPREAD CHANCE POPS ACRS THE FA FROM THE WEST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
INITIAL SHOT OF RAIN AHEAD OF THE LOW CENTER IN WRN KY LOOKS LIKE
IT WILL SLIP MAINLY S OF THE TAF SITES INITIALLY THIS MORNING.
THE 06Z NAM HAS PICKED UP NICELY ON THIS. STILL PUT IN A TEMPO
GROUP FOR CVG/LUK/ILN FOR A CHC OF MVFR VSBYS/CIGS AS THE FEATURE
SLIPS E.
SFC LOW WILL DEEPEN AS IT WORKS E TODAY. ADDITIONAL RAIN WILL
DEVELOP LATER THIS MORNING AND WILL SPREAD NWD. PCPN TYPE TODAY
SHOULD BE RAIN ACROSS ALL OF THE TAFS FOR MUCH OF THE DAY. CIGS
WILL LOWER TO MVFR AS THE PCPN SHIELD WORKS IN.
FOCUS THEN SHIFTS TO THE TIMING OF THE CHANGE OVER TO SNOW. 06Z
NAM AND THE 10Z RUC ARE INDICATING THAT THE CHANGE OVER MIGHT BE A
LITTLE SLOWER AND THE WARM AIR HANGS IN A LITTLE LONGER. BACKED
OFF ON THE CHANGE OVER BY AN HOUR OR SO...NOW 00-03Z IN THE W AND
03Z-06Z IN THE E. THE PCPN RATES WILL BE HEAVY AS THE CHANGE OVER
AS THE CHANGE OVER WILL BE DURING THE PERIOD OF MOST INTENSE
UPWARD LIFT. EXPECT A PERIOD OF MODERATE TO HEAVY SNOW AFTER THE
CHANGE OVER WITH LIFR CONDITIONS.
OUTLOOK...MVFR/IFR CONDITIONS WILL CONTINUE INTO WEDNESDAY. MVFR
CEILINGS MAY LINGER INTO THURSDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER STORM WARNING FROM 11 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR OHZ026-034-035-042>046-051>056-060>065-
070>072-077>080.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR OHZ073-074-081-082-088.
KY...WINTER STORM WARNING FROM 11 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR KYZ091>093.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR KYZ089-090-094>100.
IN...WINTER STORM WARNING FROM 11 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR INZ050-058-059-066-073-074.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR INZ075-080.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...FRANKS
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
122 AM EST TUE MAR 5 2013
.SYNOPSIS...
A WEAK RIDGE OF HIGH PRESSURE WILL MIGRATE ACROSS THE AREA EARLY
TODAY...BEFORE YIELDING TO LOW PRESSURE TRACKING EASTWARD FROM THE
MID MISSISSIPPI VALLEY ALONG THE OHIO RIVER. AS THE LOW REACHES
THE NORTH-CENTRAL APPALACHIANS THIS EVENING...A SECONDARY LOW WILL
DEVELOP OVER THE VIRGINIA/CAROLINA PIEDMONT LATE TONIGHT AND MOVE
SLOWLY NORTHEAST TOWARD THE DELMARVA PENINSULA ON WEDNESDAY BEFORE
SHIFTING OFF THE MID-ATLANTIC COAST WEDNESDAY NIGHT. THIS COMPLEX
SYSTEM WILL LIKELY BRING MODERATE TO HEAVY SNOW TO PARTS OF SOUTH-
CENTRAL PENNSYLVANIA THROUGH MID-WEEK.
&&
.NEAR TERM /UNTIL 1 PM THIS AFTERNOON/...
IR SATL TRENDS SHOW LOW CLOUDS SINKING SWWD OVR THE NERN 1/2 OF
THE CWA...REACHING A DUJ-UNV-MUI LINE AS OF 06Z. THE SW 1/2 OF THE
CWA IS MAINLY CLEAR WITH MID-HIGH CLOUDS GRADUALLY INCREASING OVR
THE FAR SW CORNER OF PA. HI-RES NAM/RUC ARE AT ODDS WITH THE
EVOLUTION OF THE LOW CLOUD COVER...WITH THE RUC INDICATING A MORE
PESSIMISTIC OUTCOME THRU THE AM HOURS. IN GENERAL KEPT SOME
CONTINUITY WITH THE PREV FCST AND WENT WITH A GRADUAL DECREASE IN
THE LOW CLOUDS THRU THE LATE AM BEFORE MID-HIGH CLOUDS WORK INTO
THE AREA FROM THE SW BY THE MID-LATE AFTN. CONSENSUS MDL/MOS BLEND
SHOWS TEMPS REACHING THE LOW-MID 30S NORTH/UPPER 30S-LOW 40S SOUTH
BY 18Z. MAIN FOCUS WILL BE ON THE UPPER LOW DIVING SEWD FROM THE
NRN PLAINS...SPAWNING SFC LOW PRES IN THE LWR OH VLY BY 12-15Z.
&&
.SHORT TERM /1 PM THIS AFTERNOON THROUGH 6 PM WEDNESDAY/...
THE NRN STREAM LOW ABDICATES TO THE BETTER MOISTURE IN THE MID MS
VALLEY...AND LOW DEVELOPS OVER KPAH EARLY IN THE DAY. THIS LOW
SHOULD RIDE UP THE OH VALLEY INTO SRN OH/ERN KY BY DAY/S END.
STRONG/HIGHLY ANOMALOUS ESE FLOW WILL RAPIDLY DEVELOP OVER THE MID
ATLANTIC STATES. THE NOSE OF THE FASTEST LOW/MID LVL FLOW WILL
EVENTUALLY POINT INTO SC PA. MAIN/PRIMARY LOW STARTS TO FILL AND
SECONDARY LOW JUST STARTING TO DEVELOP OVER VA/NC BORDER AT THE
END OF THE PD. ALMOST ALL GUIDANCE POINTS TO THE FIRST FLAKES
STARTING AROUND SUNSET IN SOMERSET CO. WILL HOLD POPS NEAR ZERO
ELSEWHERE FOR THE DAYTIME.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
EXTENDED WATCH NORTH INTO MIFFLIN...JUNIATA...PERRY...DAUPHIN AND
LEBANON COUNTIES LATEST GEFS AND SREF RUNS. STILL SIGNIFICANT
UNCERTAINTY IN NORTHWARD EXTEND OF SNOW BANDS WITH UPCOMING
SYSTEM...BUT THERE IS ENOUGH POTENTIAL FOR WARNING CRITERIA SNOWS
IN THIS AREA TO WARRANT A NORTHWARD EXTENSION IN THE WATCH. THIS
PUTS CENTRE COUNTY AND THE STATE COLLEGE AREA ON THE SOUTHERN EDGE
OF AREA OUTSIDE OF THE WATCH...BUT IT WILL BE A CLOSE CALL
LOCALLY. GEFS U-WIND ANOMALIES -3 TO -4 OVER AREA AND STRONGER TO
SE. VERY IMPRESSIVE.
PREVIOUS DISCUSSION FOLLOWS...
POTENTIAL FOR MIDWEEK WINTER STORM CONTINUES TO INCREASE AS MODELS
REMAIN CONSISTENT ON AN UPPER LOW TRACK ACROSS VA/NC BORDER TUE
NIGHT INTO WED. QPF BETWEEN MODELS COMING MORE INTO LINE AS
GRADIENT CONTINUES TO SLOWLY SHARPEN...WITH HIGHER QPFS THAT HAVE
BEGUN TO NOSE INTO SOUTHERN TIER REMAINING THERE IN 12Z RUNS...SO
POTENTIAL FOR HEAVY SNOW REMAINS. WITH ONSET OF SNOW ABOUT 26 HRS
AWAY IN THE SW /23Z TUE/...ADJUSTED HEADLINES TO UPGRADE OLD WATCH
TO A WARNING AND ADDED A RIBBON OF WINTER STORM WATCH FOR NEXT
LINE NORTH AND THEN ALONG REMAINDER OF SOUTHERN TIER WHERE
POTENTIAL DOES EXIST FOR 6+ INCHES...BUT TOTALS STILL REMAIN QUITE
FUZZY IN THAT REGION MAKING IT A TRICKY FORECAST FOR SOUTHERN AND
CENTRAL MTNS. INCREASING CONFIDENCE IN HIGHER SNOW AMOUNTS FOR SW
COUNTIES.
A BLEND OF GUIDANCE REMAINS BEST CHOICE...WITH NAM SPLITTING THE
DIFFERENCE BETWEEN THE NORTHERLY CURVING GFS AND EASTWARD
PROGRESSING ECMWF. EXPECT LIGHT SNOW TO DEVELOP DURING THE LATE
AFTERNOON HOURS OVER THE LAUREL HIGHLANDS WITH LITTLE ACCUMS EARLY
ON GIVEN WARM AFTERNOON SURFACE TEMPS. HIGHS WILL RANGE FROM THE
UPPER 30S OVER THE LAURELS AND NORTHWEST MOUNTAINS TO THE MID 40S
OVER THE SOUTHEAST.
A RATHER VIGOROUS SYSTEM WILL TRACK FROM THE LOWER OHIO VALLEY TO
THE MID ATLANTIC COAST WHILE A HIGHLY CYCLONIC AND STRONG 120+ KT
300 MB JET SUPPORTS THE LIKELIHOOD OF AN EXTENDED...18-24 HR
PERIOD OF ENHANCED SNOWFALL NEAR AND SOUTH OF THE MASON DIXON
LINE. SOME LIGHT SNOWFALL MAY EXTEND NORTHWARD TO THE CENTRAL
MOUNTAINS...BUT DO NOT EXPECT ANY ACCUMS NORTH OF I-80 AT THIS
TIME.
BEING ON THE NORTHERN EDGE OF SIGNIFICANT SNOWFALL WILL MAKE FOR
A CONTINUED CHALLENGING CALL OVER THE NEXT 24 TO 36 HOURS. A FAIR
AMOUNT OF CHANGE IN THE TRACK AND STRENGTH OF THE STORM IS STILL
POSSIBLE...EVEN AT THIS SHORT RANGE.
FOLLOWING THE STORM ON THURSDAY...A CHILLY AND RATHER GUSTY
NORTHERLY FLOW ARRIVES WITH ISOLATED TO SCATTERED MTN SNOW
SHOWERS...BEFORE HEIGHTS RISE AND DAYTIME TEMPS MODERATE TO NEAR
NORMAL BY FRIDAY AND SATURDAY. A FAST MOVING AND RELATIVELY
FLAT/WEAK NRN STREAM SHORTWAVE WILL TRACK ACROSS THE GREAT LAKES
AND NRN PENN OVER THE WEEKEND /WITH TIMING DIFFS BETWEEN
MODELS/...POSSIBLY ACCOMPANIED BY A FEW SHOWERS OF RAIN AND WET
SNOW UP NORTH. SOUTHERN PORTIONS OF PENN SHOULD STAY MAINLY DRY
THROUGH THE WEEKEND.
WARMING TREND CONTINUES INTO EARLY NEXT WEEK...WITH SIGNIFICANT
MODEL DIVERGENCE. BUT GENERAL PATTERN BRINGS INCREASED RIDGING
OVER EASTERN U.S. AS NEXT LOW PROGGED TO LIFT INTO GLAKES BY
MIDWEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
THE LOW LEVEL MOISTURE HAS BACKED UP SLOWER...AS THE EXITING LOW
IS KEEPING NORTHWESTERLY FLOW THROUGH THE REGION. THE STRATOCU
DECK IS STARTING TO WORK BACK TO THE SOUTH...SO BACKED OFF ON THE
CLEARING THE IFR FROM BFD FOR A FEW HOURS AND MVFR CIGS AT IPT AND
UNV.
THESE CIGS WILL SLOWLY LIFT BY MORNING. EXPECT IFR CIGS AT BFD
OVERNIGHT...BEFORE BEGINNING TO CLEAR OUT BY 15Z. THE NW FLOW WILL
SHIFT AND LESSEN FOR IPT AND UNV OVER THE NEXT FEW HOURS. EXPECT
VFR CIGS BY 09Z AT THE LATEST...WITH AND REMAINING STRATOCU
PULLING NORTHWARD BY 14Z. THE MID AND HIGH CLDS WILL BUILD
NORTHWARD DURING THE AFT ON TUE... AS A COMPLEX STORM MOVES EAST
FROM THE PLAINS. AT THIS POINT...EXPECT NO SNOW PRIOR TO 00Z WED.
THE STORM SYSTEM WILL CONTINUE TO MOVE EASTWARD TUESDAY
NIGHT INTO WED. EXPECT SNOW ACROSS THE AREA TUESDAY NIGHT
INTO WED EVENING. SOME OF THE SNOW WILL BE ON THE HEAVY
SIDE...ESPECIALLY ACROSS THE SOUTHERN TAF SITES.
IMPROVING CONDITIONS FOR THU INTO SAT...AS HIGH PRESSURE
BUILDS EASTWARD.
OUTLOOK...
TUE NIGHT INTO WED EVENING...IFR AND MVFR WITH AREAS OF SNOW.
THU...MVFR/IFR -SHSN EARLY...OTHERWISE VFR.
FRI-SAT...VFR CONDITIONS AS HIGH PRESSURE BUILDS EASTWARD.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM EST
WEDNESDAY FOR PAZ033>035.
WINTER STORM WATCH FROM THIS EVENING THROUGH WEDNESDAY
AFTERNOON FOR PAZ024>028-036-056-057-059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DANGELO
LONG TERM...ROSS/RXR
AVIATION...CERU/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
111 AM EST TUE MAR 5 2013
.SYNOPSIS...
A WEAK RIDGE OF HIGH PRESSURE WILL MIGRATE ACROSS THE AREA EARLY
TODAY...BEFORE YIELDING TO LOW PRESSURE TRACKING EASTWARD FROM THE
MID MISSISSIPPI VALLEY ALONG THE OHIO RIVER. AS THE LOW REACHES
THE NORTH-CENTRAL APPALACHIANS THIS EVENING...A SECONDARY LOW WILL
DEVELOP OVER THE VIRGINIA/CAROLINA PIEDMONT LATE TONIGHT AND MOVE
SLOWLY NORTHEAST TOWARD THE DELMARVA PENINSULA ON WEDNESDAY BEFORE
SHIFTING OFF THE MID-ATLANTIC COAST WEDNESDAY NIGHT. THIS COMPLEX
SYSTEM WILL LIKELY BRING MODERATE TO HEAVY SNOW TO PARTS OF SOUTH-
CENTRAL PENNSYLVANIA THROUGH MID-WEEK.
&&
.NEAR TERM /UNTIL 1 PM THIS AFTERNOON/...
IR SATL TRENDS SHOW LOW CLOUDS SINKING SWWD OVR THE NERN 1/2 OF
THE CWA...REACHING A DUJ-UNV-MUI LINE AS OF 06Z. THE SW 1/2 OF THE
CWA IS MAINLY CLEAR WITH MID-HIGH CLOUDS GRADUALLY INCREASING OVR
THE FAR SW CORNER OF PA. HI-RES NAM/RUC ARE AT ODDS WITH THE
EVOLUTION OF THE LOW CLOUD COVER...WITH THE RUC INDICATING A MORE
PESSIMISTIC OUTCOME THRU THE AM HOURS. IN GENERAL KEPT SOME
CONTINUITY WITH THE PREV FCST AND WENT WITH A GRADUAL DECREASE IN
THE LOW CLOUDS THRU THE LATE AM BEFORE MID-HIGH CLOUDS WORK INTO
THE AREA FROM THE SW BY THE MID-LATE AFTN. CONSENSUS MDL/MOS BLEND
SHOWS TEMPS REACHING THE LOW-MID 30S NORTH/UPPER 30S-LOW 40S SOUTH
BY 18Z. MAIN FOCUS WILL BE ON THE UPPER LOW DIVING SEWD FROM THE
NRN PLAINS...SPAWNING SFC LOW PRES IN THE LWR OH VLY BY 12-15Z.
&&
.SHORT TERM /1 PM THIS AFTERNOON THROUGH 6 PM WEDNESDAY/...
THE NRN STREAM LOW ABDICATES TO THE BETTER MOISTURE IN THE MID MS
VALLEY...AND LOW DEVELOPS OVER KPAH EARLY IN THE DAY. THIS LOW
SHOULD RIDE UP THE OH VALLEY INTO SRN OH/ERN KY BY DAY/S END.
STRONG/HIGHLY ANOMALOUS ESE FLOW WILL RAPIDLY DEVELOP OVER THE MID
ATLANTIC STATES. THE NOSE OF THE FASTEST LOW/MID LVL FLOW WILL
EVENTUALLY POINT INTO SC PA. MAIN/PRIMARY LOW STARTS TO FILL AND
SECONDARY LOW JUST STARTING TO DEVELOP OVER VA/NC BORDER AT THE
END OF THE PD. ALMOST ALL GUIDANCE POINTS TO THE FIRST FLAKES
STARTING AROUND SUNSET IN SOMERSET CO. WILL HOLD POPS NEAR ZERO
ELSEWHERE FOR THE DAYTIME.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
EXTENDED WATCH NORTH INTO MIFFLIN...JUNIATA...PERRY...DAUPHIN AND
LEBANON COUNTIES LATEST GEFS AND SREF RUNS. STILL SIGNIFICANT
UNCERTAINTY IN NORTHWARD EXTEND OF SNOW BANDS WITH UPCOMING
SYSTEM...BUT THERE IS ENOUGH POTENTIAL FOR WARNING CRITERIA SNOWS
IN THIS AREA TO WARRANT A NORTHWARD EXTENSION IN THE WATCH. THIS
PUTS CENTRE COUNTY AND THE STATE COLLEGE AREA ON THE SOUTHERN EDGE
OF AREA OUTSIDE OF THE WATCH...BUT IT WILL BE A CLOSE CALL
LOCALLY. GEFS U-WIND ANOMALIES -3 TO -4 OVER AREA AND STRONGER TO
SE. VERY IMPRESSIVE.
PREVIOUS DISCUSSION FOLLOWS...
POTENTIAL FOR MIDWEEK WINTER STORM CONTINUES TO INCREASE AS MODELS
REMAIN CONSISTENT ON AN UPPER LOW TRACK ACROSS VA/NC BORDER TUE
NIGHT INTO WED. QPF BETWEEN MODELS COMING MORE INTO LINE AS
GRADIENT CONTINUES TO SLOWLY SHARPEN...WITH HIGHER QPFS THAT HAVE
BEGUN TO NOSE INTO SOUTHERN TIER REMAINING THERE IN 12Z RUNS...SO
POTENTIAL FOR HEAVY SNOW REMAINS. WITH ONSET OF SNOW ABOUT 26 HRS
AWAY IN THE SW /23Z TUE/...ADJUSTED HEADLINES TO UPGRADE OLD WATCH
TO A WARNING AND ADDED A RIBBON OF WINTER STORM WATCH FOR NEXT
LINE NORTH AND THEN ALONG REMAINDER OF SOUTHERN TIER WHERE
POTENTIAL DOES EXIST FOR 6+ INCHES...BUT TOTALS STILL REMAIN QUITE
FUZZY IN THAT REGION MAKING IT A TRICKY FORECAST FOR SOUTHERN AND
CENTRAL MTNS. INCREASING CONFIDENCE IN HIGHER SNOW AMOUNTS FOR SW
COUNTIES.
A BLEND OF GUIDANCE REMAINS BEST CHOICE...WITH NAM SPLITTING THE
DIFFERENCE BETWEEN THE NORTHERLY CURVING GFS AND EASTWARD
PROGRESSING ECMWF. EXPECT LIGHT SNOW TO DEVELOP DURING THE LATE
AFTERNOON HOURS OVER THE LAUREL HIGHLANDS WITH LITTLE ACCUMS EARLY
ON GIVEN WARM AFTERNOON SURFACE TEMPS. HIGHS WILL RANGE FROM THE
UPPER 30S OVER THE LAURELS AND NORTHWEST MOUNTAINS TO THE MID 40S
OVER THE SOUTHEAST.
A RATHER VIGOROUS SYSTEM WILL TRACK FROM THE LOWER OHIO VALLEY TO
THE MID ATLANTIC COAST WHILE A HIGHLY CYCLONIC AND STRONG 120+ KT
300 MB JET SUPPORTS THE LIKELIHOOD OF AN EXTENDED...18-24 HR
PERIOD OF ENHANCED SNOWFALL NEAR AND SOUTH OF THE MASON DIXON
LINE. SOME LIGHT SNOWFALL MAY EXTEND NORTHWARD TO THE CENTRAL
MOUNTAINS...BUT DO NOT EXPECT ANY ACCUMS NORTH OF I-80 AT THIS
TIME.
BEING ON THE NORTHERN EDGE OF SIGNIFICANT SNOWFALL WILL MAKE FOR
A CONTINUED CHALLENGING CALL OVER THE NEXT 24 TO 36 HOURS. A FAIR
AMOUNT OF CHANGE IN THE TRACK AND STRENGTH OF THE STORM IS STILL
POSSIBLE...EVEN AT THIS SHORT RANGE.
FOLLOWING THE STORM ON THURSDAY...A CHILLY AND RATHER GUSTY
NORTHERLY FLOW ARRIVES WITH ISOLATED TO SCATTERED MTN SNOW
SHOWERS...BEFORE HEIGHTS RISE AND DAYTIME TEMPS MODERATE TO NEAR
NORMAL BY FRIDAY AND SATURDAY. A FAST MOVING AND RELATIVELY
FLAT/WEAK NRN STREAM SHORTWAVE WILL TRACK ACROSS THE GREAT LAKES
AND NRN PENN OVER THE WEEKEND /WITH TIMING DIFFS BETWEEN
MODELS/...POSSIBLY ACCOMPANIED BY A FEW SHOWERS OF RAIN AND WET
SNOW UP NORTH. SOUTHERN PORTIONS OF PENN SHOULD STAY MAINLY DRY
THROUGH THE WEEKEND.
WARMING TREND CONTINUES INTO EARLY NEXT WEEK...WITH SIGNIFICANT
MODEL DIVERGENCE. BUT GENERAL PATTERN BRINGS INCREASED RIDGING
OVER EASTERN U.S. AS NEXT LOW PROGGED TO LIFT INTO GLAKES BY
MIDWEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SOME MINOR CHANGES TO THE 03Z TAFS.
THE SC DECK STARTING TO WORK BACK TO THE SOUTH...SO DID
BACK OFF ON THE CLEARING AT BFD FOR A FEW HOURS. FOR
UNV...SHOULD REMAIN CLEAR. MVFR CIG AT IPT.
MID AND HIGH CLDS WILL BUILD NORTHWARD DURING THE AFT ON TUE...
AS A COMPLEX STORM MOVES EAST FROM THE PLAINS. AT THIS
POINT...EXPECT NO SNOW PRIOR TO 00Z WED.
THE STORM SYSTEM WILL CONTINUE TO MOVE EASTWARD TUESDAY
NIGHT INTO WED. EXPECT SNOW ACROSS THE AREA TUESDAY NIGHT
INTO WED EVENING. SOME OF THE SNOW WILL BE ON THE HEAVY
SIDE...ESPECIALLY ACROSS THE SOUTHERN TAF SITES.
IMPROVING CONDITIONS FOR THU INTO SAT...AS HIGH PRESSURE
BUILDS EASTWARD.
OUTLOOK...
TUE NIGHT INTO WED EVENING...IFR AND MVFR WITH AREAS OF SNOW.
THU...MVFR/IFR -SHSN EARLY...OTHERWISE VFR.
FRI-SAT...VFR CONDITIONS AS HIGH PRESSURE BUILDS EASTWARD.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM EST
WEDNESDAY FOR PAZ033>035.
WINTER STORM WATCH FROM THIS EVENING THROUGH WEDNESDAY
AFTERNOON FOR PAZ024>028-036-056-057-059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DANGELO
LONG TERM...ROSS/RXR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1256 PM EST TUE MAR 5 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL PASS OVER THE AREA TONIGHT AND EARLY
WEDNESDAY BRINGING RAIN AND SNOW SHOWERS TO THE WESTERN CAROLINAS.
DRIER HIGH PRESSURE WILL RETURN IN ITS WAKE AND LINGER THROUGH THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1125 AM EST...THE MAIN MORNING UPDATE CONCERNS INCLUDE ADJ TO
POPS AND SKY COVER. THE LATEST VIS IS SHOWING A DRYING WARM SECTOR
AHEAD OF THE COLD FRONT ACROSS NE GA AND THE SW/RN UPSTATE. THIS
SHOULD FILL IN A LITTLE AS THE AFTERNOON PROGRESSES WITH MOIST ADV
AND DEVELOPING CONVECTION. POPS WERE ALSO ADJ DOWN ACROSS GA...THE
UPSTATE AND INTO THE SRN NC PIEDMONT. THE LATEST HRRR COMP REFLECT
HAS A GOOD HANDLE ON THE PLACEMENT AND EVOLUTION OF THE RETURNS SEEN
ON THE 88D AND IT/S PROGS WERE BLENDED INTO THE GRIDS. MAX TEMPS
WILL BE TRICKY THIS AFTERNOON WITH THE POSSIBLE ADDED INSOL EARLY ON
OVER THE SRN ZONES...AND MAY NEED ANOTHER SIGFNT UPDATE EARLY THIS
AFTERNOON. FOR NOW WENT WITH A EVEN RATIO OF THE NAM/GFS THICKNESS
SCHEME AND BLENDED THAT WITH THE LATEST MAVMOS AND OFFICIAL
FCST.
AS OF 949 AM EST...THE OVERALL FCST IS IN GOOD SHAPE. RADAR IS
BEGINNING TO FILL IN WITH STRONGER RETURNS ACROSS THE NC PIEDMONT
AND FOOTHILLS ASSOCIATED WITH AN ULVL DIFFLUENT ZONE. ALSO...STEEP
H7/H5 LAPSE RATES ARE MAINTAINING ENOUGH CHARGE SEPARATION FOR
THUNDER ACROSS ERN TN AND THIS WILL BE MOVING INTO THE WRN NC MTNS
WITHIN THE NEXT HR. THE GRIDS ACROSS THE WRN MOST NC ZONES WERE THUS
UPDATED TO INCLUDE ISOL TSTMS.
AS OF 645 AM EST...WATER VAPOR IMAGERY SHOWS THE DEEPENING UPPER LOW
PRESSURE CENTER MOVING SE ACROSS IOWA THIS MORNING. RETURNING LOW
LEVEL MOISTURE AND ISENTROPIC LIFT WELL SE OF THIS SYSTEM IS
STARTING TO PRODUCE SOME LIGHT RADAR RETURNS FROM THE SW.
FORTUNATELY...THE CHILLY CENTRAL AND SRN MTN VALLEY TEMPS HAVE
GENERALLY REBOUNDED ABOVE THE FREEZING MARK...WITH JUST A FEW NRN
MTN LOCATIONS STILL RUNNING 30 TO 32 DEGREES. VERY SPOTTY LIGHT
FREEZING RAIN WILL BE POSSIBLE IN NRN MTN SECTIONS FOR THE NEXT
COUPLE OF HOURS...BUT WITH QPF TOO LIGHT FOR ANY ICING PROBLEMS.
OTHERWISE...THE FORECAST IS ON TRACK WITH IMPROVING LOW LEVEL
UPGLIDE MOISTURE STEADILY INCREASING ACROSS THE FORECAST AREA
THROUGH THE DAY...WITH INCREASING/EXPANDING POPS RESULTING. 850 MB
WINDS WILL SLOWLY BACK AND STRENGTHEN BY LATE AFTERNOON IN THE WARM
SECTOR ACROSS THE REGION...AND SFC BASED INSTABILITY WILL INCREASE
ENOUGH BY LATE DAY TO WARRANT A SCHC TO CHC TSTM MENTION OVER SRN
SECTIONS...AND ALSO OVER THE WRN MTNS WITH IMPROVING LAPSE RATES
ALOFT. IN ADDITION...40 TO 50 KT OF LOW LEVEL SHEAR WILL WARRANT AN
ISOLD SEVERE THREAT MENTION TOWARD EVENING IN THE SRN
PIEDMONT...WITH BL HELICITY VALUES AT OR ABOVE 500 M2/S2 CROSSING
THE REGION TOWARD 00Z.
THE STRONGEST 850 TO 500 MB DPVA SHOULD TRANSIT THE FORECAST AREA
MAINLY 00Z TO 06Z AHEAD OF THE DEEP H5 LOW PRES CENTER MOVING FROM
THE LOWER OH VALLEY THROUGH THE SRN APPALACHIANS. THE ASSOCIATED SFC
COLD FRONT WILL MOVE QUICKLY THROUGH THE REGION CENTERED AROUND
03Z...WITH PROFILES RAPIDLY BECOMING COLD ENOUGH TO SUPPORT SNOW
OVER THE HIGHER TERRAIN...AND THEN THROUGHOUT THE LOWEST VALLEYS
OVERNIGHT IN IMPROVING MOIST NW UPSLOPE FLOW. THE QUICK SHOT OF DEEP
EVENING MOISTURE WILL MOVE EAST OF THE AREA...WITH PROMINENT MID
LEVEL DRYING ARRIVING ACROSS THE FOOTHILLS AND PIEDMONT FROM THE SW
BY 06Z. HOWEVER...ADDITIONAL DEEPER MOISTURE WILL THEN WRAP SWD
BEHIND THE PASSING CYCLONE TOWARD DAYBREAK WED TO ADD TO SNOWFALL
TOTALS OVER THE WRN MTNS IN BLOSSOMING NW UPSLOPE FLOW IN THE VERY
COLD AIR. THE WINTER STORM WATCH WILL BE UPGRADED TO A
WARNING...WITH AN ADVISORY TIER ADDED FOR BUNCOMBE AND MACON. IN
ADDITION...EXPECT VERY WINDY CONDITIONS OVER THE MTNS WITH THE COLD
ADVECTION AND 50 KT OF 850 MB FLOW. WIND HAZARDS WILL BE WRAPPED
INTO THE WINTER STORM PRODUCTS...EXCEPT FOR A STANDALONE WIND
ADVISORY FOR MCDOWELL MTNS TO CALDWELL MTNS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 1 PM TUESDAY...NORTHWEST FLOW ALOFT WILL DOMINATE THE SHORT
RANGE PERIOD AS A CUTOFF UPPER LOW OFF THE EAST COAST IS BLOCKED
FROM ESCAPE TO THE EAST. ANOTHER UPPER LOW/SHORT WAVE WILL BE
ASSIMILATED THURSDAY NIGHT AND FRIDAY...BUT THIS WILL MOVE PAST WELL
TO OUR NORTHEAST. THUS...FOR THE MOST PART...WE WILL REMAIN UNDER
THE INFLUENCE OF COLD HIGH PRESSURE BUILDING IN FROM THE NORTHWEST
THROUGH FRIDAY. THE PRODUCTION OF SNOW ALONG THE TN BORDER WILL
CONTINUE WEDNESDAY NIGHT AS MOISTURE MOVES DOWN FROM THE NW...BUT
THIS SHOULD WANE ON THURSDAY MORNING AS THE MOISTURE PULLS OUT.
PRECIP CHANCES START OUT LIKELY ON THE TN BORDER WEDNESDAY EVE AND
THEN TAPER OFF FROM THERE...ENDING BY MIDDAY ON THURSDAY. IT STILL
LOOKS LIKE THERE IS THE POTENTIAL FOR ANOTHER INCH OR TWO WEDNESDAY
NIGHT...SO THE WARNING CONTINUATION THROUGH SUNRISE THURSDAY LOOKS
TO BE RIGHT ON TRACK. THIS ACTIVITY IS NOT EXPECTED TO MAKE IT EAST
OF THE BLUE RIDGE. TEMPERATURES SHOULD MODERATE THROUGH THE
PERIOD...WITH HIGHS THURSDAY ABOUT FIVE DEGREES WARMER THAN
WEDNESDAY...THEN ANOTHER CATEGORY OR SO WARMER AGAIN ON FRIDAY. LOW
TEMPS WILL ALSO SHOW A MODERATING TREND...ALTHO NOT AS PRONOUNCED.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 215 AM EST TUESDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
FRIDAY WITH A COMPLEX UPPER LOW GRADUALLY MOVING OFF THE NEW ENGLAND
COAST AND UPPER RIDGING MOVING OVER THE CAROLINAS. RIDGING IS
EXPECTED TO LINGER THRU MOST OF THE WEEKEND WHILE ANOTHER DEEP UPPER
TROF DRIFTS ACROSS THE WESTERN CONUS. THE LONG RANGE MODELS BEGIN TO
DIVERGE WRT TO THE EVOLUTION OF THIS TROF LATE IN THE WEEKEND WITH
THE ECMWF CLOSING OFF A VERY LARGE AND BROAD CLOSED H5 LOW AND VERY
GRADUALLY MOVING THE LOW TOWARDS THE FCST AREA. ANY IMPACTS ON OUR
SENSIBLE WX WOULD NOT BE SEEN UNTIL LATER NEXT WEEK. ON THE OTHER
HAND...THE MORE PROGRESSIVE GFS DOESNT QUITE CLOSE THE LOW OFF FROM
THE NORTHERN STREAM FLOW AND AS A RESULT...BRINGS A HEALTHY AMOUNT
OF H5 PVA TO OUR DOORSTEP BY LATE MONDAY INTO EARLY TUESDAY. FOR THE
TIME BEING...MOST OF THE GUIDANCE IS FAVORING A LESS PROGRESSIVE
SOLUTION WITH PERSISTENT UPPER RIDGING IN PLACE THRU DAY 7.
AT THE SFC...COOL CANADIAN HIGH PRESSURE MOVES BACK INTO THE AREA ON
THURS AND IS EXPECTED TO LINGER THRU THE WEEKEND. THE MODELS INDICATE
A LOW WILL DEEPEN EAST OF THE ROCKIES ON SUNDAY AND DRIFT EASTWARD
EARLY NEXT WEEK. THE SLOWER ECMWF SOLUTION KEEPS THE LOW AND ITS
COLD FRONT TO OUR WEST UNTIL THE VERY END OF THE PERIOD WHILE THE
FASTER GFS MOVES THE FRONT OVER THE CWFA ON MONDAY. EITHER WAY...LOW
LVL FLOW SHOULD BECOME MORE SLY AND MOISTEN BY EARLY NEXT WEEK AS
THE HIGH SLIDES FARTHER EAST. I HAVE POPS RAMPING UP TO SOLID CHANCE
OVER MOST OF THE CWFA BY TUES MORNING WITH THE HIGHEST VALUES OVER
THE WESTERN ZONES. OTHERWISE...THE PERIOD WILL BE DRY WITH TEMPS
WARMING THRU THE WEEKEND AND THEN LEVELING OFF EARLY NEXT WEEK. BY
SUNDAY...HIGHS ARE EXPECTED TO REACH THE MID 60S FOR THE LOWER
ELEVATIONS AND UPPER 50S TO LOWER 60S FOR THE HIGHER TERRAIN.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...UNEXPECTED CLEARING SKIES ARE MAKING HEADWAY TOWARD THE
TERMINAL AND THIS WILL BE METWATCHED FOR A PROBABLE AMD TO VFR OVER
THE NEXT COUPLE HRS. POPS HAVE BEEN ADJ DOWN AS WELL WITH -SHRA OR
DEEPER CONVECTION NOT ANTICIPATED TILL 20Z. THE TIMING OF THIS IS ALSO
SUSPECT AND WILL NEED TO BE MONITORED. A STRONG LLVL JET WILL CROSS
THE TERMINAL AFT 00Z AND THERE COULD BE SOME WS ISSUES NOT
ASSOCIATED WITH TSTMS OR TALL CONVECTION. AFTER FROPA ARD 03Z...SFC
GUSTS WILL PICK UP AND REMAIN THROUGH THE END OF THE TAF PERIOD. VFR
CIGS RETURN POST FROPA.
AT KAVL...MVFR CIGS WILL PERSIST THROUGH MOST OF THE PERIOD AS COLD
FRONT APPROACHES FROM THE WEST. FROPA IS AFT 00Z...BUT MOIST FLOW UP
THE FRENCH BROAD VALLEY WILL ENABLE LOW CIGS. A RETURN TO VFR IS
EXPECT AFT 11Z WITH LLVL UPSTREAM MOISTURE WANING. MODERATE SFC WIND
GUSTS WILL DEVELOP AFT FROPA AS WELL AND REMAIN THROUGH THE TAF
PERIOD.
ELSEWHERE...A LARGE ARE OF DRYING HAS DEVELOPED IN THE WARM SECTOR
AND EXPECT KAND TO REMAIN VFR TILL PERIODS OF CONVECTION APPROACHE
AFT 20Z. KGSP AND KGMU REMAIN RIGHT ON THE BORDER OF THE SCT
CLOUDS...BUT WILL KEEP MVFR FOR NOW BASED ON VIS SAT LOOP. A 3 HR
TEMPO THUNDER WAS INCLUDED AT KAND BEGINNING AT 00Z WITH SBCAPE
VALUES APPROACHING 400 J/KG BY THAT TIME. FROPA WILL OCCUR AND CIGS
SHOULD RETURN TO VFR AT ALL SITES AFT 04Z. WINDS WILL RESPOND TO A
STRONG P/GRAD BEHIND THE FRONT AND DOWNWARD MIXING AND ENABLE
MODERATE GUSTS THROUGH THE PERIOD.
OUTLOOK...WINDY NW FLOW CONDITIONS WILL PERSIST WED INTO WED NIGHT
AS STRONG LOW PRES PULLS AWAY OFF THE MID ATLANTIC COAST. LINGERING
RESTRICTIONS AND NEARBY SHSN WILL CONTINUE TO IMPACT KAVL THROUGH
WED. STRONG DRY RIDGING WILL THEN DEVELOP THU THROUGH THE WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 92% HIGH 81% HIGH 100% HIGH 100%
KGSP HIGH 86% HIGH 94% HIGH 100% HIGH 100%
KAVL HIGH 80% MED 73% MED 71% HIGH 100%
KHKY HIGH 95% HIGH 82% HIGH 100% HIGH 100%
KGMU HIGH 85% HIGH 88% HIGH 100% HIGH 100%
KAND HIGH 81% HIGH 94% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST WEDNESDAY
NIGHT FOR NCZ501-503-505.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 6 AM EST
THURSDAY FOR NCZ033-048>052-058-059.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST
WEDNESDAY NIGHT FOR NCZ053-062.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...HG/SBK
SHORT TERM...NED
LONG TERM...JPT
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1136 AM EST TUE MAR 5 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL PASS OVER THE AREA TONIGHT AND EARLY
WEDNESDAY BRINGING RAIN AND SNOW SHOWERS TO THE WESTERN CAROLINAS.
DRIER HIGH PRESSURE WILL RETURN IN ITS WAKE AND LINGER THROUGH THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1125 AM EST...THE MAIN MORNING UPDATE CONCERNS INCLUDE ADJ TO
POPS AND SKY COVER. THE LATEST VIS IS SHOWING A DRYING WARM SECTOR
AHEAD OF THE COLD FRONT ACROSS NE GA AND THE SW/RN UPSTATE. THIS
SHOULD FILL IN A LITTLE AS THE AFTERNOON PROGRESSES WITH MOIST ADV
AND DEVELOPING CONVECTION. POPS WERE ALSO ADJ DOWN ACROSS GA...THE
UPSTATE AND INTO THE SRN NC PIEDMONT. THE LATEST HRRR COMP REFLECT
HAS A GOOD HANDLE ON THE PLACEMENT AND EVOLUTION OF THE RETURNS SEEN
ON THE 88D AND IT/S PROGS WERE BLENDED INTO THE GRIDS. MAX TEMPS
WILL BE TRICKY THIS AFTERNOON WITH THE POSSIBLE ADDED INSOL EARLY ON
OVER THE SRN ZONES...AND MAY NEED ANOTHER SIGFNT UPDATE EARLY THIS
AFTERNOON. FOR NOW WENT WITH A EVEN RATIO OF THE NAM/GFS THICKNESS
SCHEME AND BLENDED THAT WITH THE LATEST MAVMOS AND OFFICIAL
FCST.
AS OF 949 AM EST...THE OVERALL FCST IS IN GOOD SHAPE. RADAR IS
BEGINNING TO FILL IN WITH STRONGER RETURNS ACROSS THE NC PIEDMONT
AND FOOTHILLS ASSOCIATED WITH AN ULVL DIFFLUENT ZONE. ALSO...STEEP
H7/H5 LAPSE RATES ARE MAINTAINING ENOUGH CHARGE SEPARATION FOR
THUNDER ACROSS ERN TN AND THIS WILL BE MOVING INTO THE WRN NC MTNS
WITHIN THE NEXT HR. THE GRIDS ACROSS THE WRN MOST NC ZONES WERE THUS
UPDATED TO INCLUDE ISOL TSTMS.
AS OF 645 AM EST...WATER VAPOR IMAGERY SHOWS THE DEEPENING UPPER LOW
PRESSURE CENTER MOVING SE ACROSS IOWA THIS MORNING. RETURNING LOW
LEVEL MOISTURE AND ISENTROPIC LIFT WELL SE OF THIS SYSTEM IS
STARTING TO PRODUCE SOME LIGHT RADAR RETURNS FROM THE SW.
FORTUNATELY...THE CHILLY CENTRAL AND SRN MTN VALLEY TEMPS HAVE
GENERALLY REBOUNDED ABOVE THE FREEZING MARK...WITH JUST A FEW NRN
MTN LOCATIONS STILL RUNNING 30 TO 32 DEGREES. VERY SPOTTY LIGHT
FREEZING RAIN WILL BE POSSIBLE IN NRN MTN SECTIONS FOR THE NEXT
COUPLE OF HOURS...BUT WITH QPF TOO LIGHT FOR ANY ICING PROBLEMS.
OTHERWISE...THE FORECAST IS ON TRACK WITH IMPROVING LOW LEVEL
UPGLIDE MOISTURE STEADILY INCREASING ACROSS THE FORECAST AREA
THROUGH THE DAY...WITH INCREASING/EXPANDING POPS RESULTING. 850 MB
WINDS WILL SLOWLY BACK AND STRENGTHEN BY LATE AFTERNOON IN THE WARM
SECTOR ACROSS THE REGION...AND SFC BASED INSTABILITY WILL INCREASE
ENOUGH BY LATE DAY TO WARRANT A SCHC TO CHC TSTM MENTION OVER SRN
SECTIONS...AND ALSO OVER THE WRN MTNS WITH IMPROVING LAPSE RATES
ALOFT. IN ADDITION...40 TO 50 KT OF LOW LEVEL SHEAR WILL WARRANT AN
ISOLD SEVERE THREAT MENTION TOWARD EVENING IN THE SRN
PIEDMONT...WITH BL HELICITY VALUES AT OR ABOVE 500 M2/S2 CROSSING
THE REGION TOWARD 00Z.
THE STRONGEST 850 TO 500 MB DPVA SHOULD TRANSIT THE FORECAST AREA
MAINLY 00Z TO 06Z AHEAD OF THE DEEP H5 LOW PRES CENTER MOVING FROM
THE LOWER OH VALLEY THROUGH THE SRN APPALACHIANS. THE ASSOCIATED SFC
COLD FRONT WILL MOVE QUICKLY THROUGH THE REGION CENTERED AROUND
03Z...WITH PROFILES RAPIDLY BECOMING COLD ENOUGH TO SUPPORT SNOW
OVER THE HIGHER TERRAIN...AND THEN THROUGHOUT THE LOWEST VALLEYS
OVERNIGHT IN IMPROVING MOIST NW UPSLOPE FLOW. THE QUICK SHOT OF DEEP
EVENING MOISTURE WILL MOVE EAST OF THE AREA...WITH PROMINENT MID
LEVEL DRYING ARRIVING ACROSS THE FOOTHILLS AND PIEDMONT FROM THE SW
BY 06Z. HOWEVER...ADDITIONAL DEEPER MOISTURE WILL THEN WRAP SWD
BEHIND THE PASSING CYCLONE TOWARD DAYBREAK WED TO ADD TO SNOWFALL
TOTALS OVER THE WRN MTNS IN BLOSSOMING NW UPSLOPE FLOW IN THE VERY
COLD AIR. THE WINTER STORM WATCH WILL BE UPGRADED TO A
WARNING...WITH AN ADVISORY TIER ADDED FOR BUNCOMBE AND MACON. IN
ADDITION...EXPECT VERY WINDY CONDITIONS OVER THE MTNS WITH THE COLD
ADVECTION AND 50 KT OF 850 MB FLOW. WIND HAZARDS WILL BE WRAPPED
INTO THE WINTER STORM PRODUCTS...EXCEPT FOR A STANDALONE WIND
ADVISORY FOR MCDOWELL MTNS TO CALDWELL MTNS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM MONDAY...BY 12Z WED...SHORT RANGE MODELS INDICATE THAT
THE H5 LOW WILL BE CENTERED OVER KGSO WITH THE SFC LOW CENTERED OVER
THE TIDEWATER OF VA. WED MORNING...LLVL FLOW ACROSS THE TN BORDER
COUNTIES OF NC IS EXPECTED TO FAVOR WNW DIRECTION...A LITTLE WEST OF
OPTIMAL NWFS GENERATION. HOWEVER...THE CLOSED LOW AND SFC LOW WILL
TRACK EAST DURING THE DAY...RESULTING IN VEERING LLVL FLOW ACROSS
THE FORECAST AREA. WIND DIRECTION AND SPEEDS ACROSS THE SOUTHERN
APPALACHIAN REGION ARE FORECAST TO BECOME VERY FAVORABLE FOR NWFS BY
MID DAY WEDNESDAY. FORECAST SOUNDINGS ACROSS NC MTNS AND EASTERN TN
SITES INDICATE THAT THE LAYER OF SATURATED AIR SHOULD EXTEND FROM
THE BL TO H65 EARLY WEDNESDAY...GRADUALLY FADING TO A H9 TO H75 BY
LATE AFTERNOON. BASED ON WIND TIMING...MOISTURE CONTENT...AND
TEMPERATURE PROFILES...CONDITIONS APPEAR VERY FAVORABLE FOR
ACCUMULATING NWFS WEDNESDAY MORNING UNTIL THE EARLY AFTERNOON.
DURING THIS TIME WINDOW...I WILL INDICATE HOURLY QPF AMOUNTS FROM
0.03 INCHES ALONG THE TN LINE. SLR VALUES OF 12 TO 14 TO 1 WILL
RESULT IN HOURLY SNOWFALL RATES FROM 0.25 TO 0.4 OF AN INCH ACROSS
THE FAVORED UPSLOPE AREAS. TOTAL DAYLIGHT SNOWFALL ACROSS THE MTNS
ON WEDNESDAY IS FORECAST TO RANGE FROM NEAR 4 INCHES ALONG THE SPINE
OF THE APPALACHIANS TO 1 TO 3 INCHES ACROSS THE TN BORDER COUNTIES.
IN ADDITION...WINDS ACROSS THE MTNS WILL BECOME QUITE GUSTY THROUGH
THE DAY...REACHING WIND ADVISORY CRITERIA LEVELS. EAST OF THE
MTNS...CONDITIONS WILL REMAIN BREEZY...DRY...WITH DECREASING SKY
COVER. HIGHS ARE FORECAST TO RANGE FROM NEAR 40 WITHIN THE MTN
VALLEYS TO NEAR 50 EAST.
WEDNESDAY NIGHT...ACCUMULATING SNOWFALL WILL GRADUALLY DISSIPATE
ACROSS THE NC MTNS AS MOISTURE AND WINDS DECREASE. HOWEVER...THE
FAVORED UPSLOPE AREAS MAY SEE AN ADDITIONAL INCH OF SNOW. MIN
TEMPERATURES ARE FORECAST TO RANGE FROM THE 20S ACROSS THE MTNS TO
AROUND FREEZING EAST. CANADIAN HIGH PRESSURE WILL BEGIN TO BUILD
OVER THE REGION ON THURSDAY. MID LEVEL HEIGHTS AND H85 TEMPERATURES
WILL SLOWLY INCREASE THROUGH THE DAY. THE COMBINATION OF GOOD
INSOLATION AND RISING THICKNESSES SHOULD ALLOW TEMPERATURES TO WARM
SIGNIFICANTLY FROM WEDNESDAY...BUT FALLING SHORT OF NORMALS BY 5 TO
7 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 215 AM EST TUESDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
FRIDAY WITH A COMPLEX UPPER LOW GRADUALLY MOVING OFF THE NEW ENGLAND
COAST AND UPPER RIDGING MOVING OVER THE CAROLINAS. RIDGING IS
EXPECTED TO LINGER THRU MOST OF THE WEEKEND WHILE ANOTHER DEEP UPPER
TROF DRIFTS ACROSS THE WESTERN CONUS. THE LONG RANGE MODELS BEGIN TO
DIVERGE WRT TO THE EVOLUTION OF THIS TROF LATE IN THE WEEKEND WITH
THE ECMWF CLOSING OFF A VERY LARGE AND BROAD CLOSED H5 LOW AND VERY
GRADUALLY MOVING THE LOW TOWARDS THE FCST AREA. ANY IMPACTS ON OUR
SENSIBLE WX WOULD NOT BE SEEN UNTIL LATER NEXT WEEK. ON THE OTHER
HAND...THE MORE PROGRESSIVE GFS DOESNT QUITE CLOSE THE LOW OFF FROM
THE NORTHERN STREAM FLOW AND AS A RESULT...BRINGS A HEALTHY AMOUNT
OF H5 PVA TO OUR DOORSTEP BY LATE MONDAY INTO EARLY TUESDAY. FOR THE
TIME BEING...MOST OF THE GUIDANCE IS FAVORING A LESS PROGRESSIVE
SOLUTION WITH PERSISTENT UPPER RIDGING IN PLACE THRU DAY 7.
AT THE SFC...COOL CANADIAN HIGH PRESSURE MOVES BACK INTO THE AREA ON
THURS AND IS EXPECTED TO LINGER THRU THE WEEKEND. THE MODELS INDICATE
A LOW WILL DEEPEN EAST OF THE ROCKIES ON SUNDAY AND DRIFT EASTWARD
EARLY NEXT WEEK. THE SLOWER ECMWF SOLUTION KEEPS THE LOW AND ITS
COLD FRONT TO OUR WEST UNTIL THE VERY END OF THE PERIOD WHILE THE
FASTER GFS MOVES THE FRONT OVER THE CWFA ON MONDAY. EITHER WAY...LOW
LVL FLOW SHOULD BECOME MORE SLY AND MOISTEN BY EARLY NEXT WEEK AS
THE HIGH SLIDES FARTHER EAST. I HAVE POPS RAMPING UP TO SOLID CHANCE
OVER MOST OF THE CWFA BY TUES MORNING WITH THE HIGHEST VALUES OVER
THE WESTERN ZONES. OTHERWISE...THE PERIOD WILL BE DRY WITH TEMPS
WARMING THRU THE WEEKEND AND THEN LEVELING OFF EARLY NEXT WEEK. BY
SUNDAY...HIGHS ARE EXPECTED TO REACH THE MID 60S FOR THE LOWER
ELEVATIONS AND UPPER 50S TO LOWER 60S FOR THE HIGHER TERRAIN.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...UPSTATE SC OBS TO THE SW HAVE SHOWN A MORE RAPID TREND
DOWNWARD TOWARD MVFR THIS MORNING...AND THE LOWERING THROUGH VFR
TOWARD MVFR AT KCLT WILL BE HASTENED AS WELL. RAIN OR SHOWER CHANCES
WILL IMPROVE THROUGH THE AFTERNOON AS UPGLIDE MOISTURE INCREASES.
THERE WILL BE IMPROVING SFC BASED INSTABILITY VERY LATE IN THE
DAY...BUT WITH CONFIDENCE ON ANY DEEPER CONVECTION AHEAD OF THE
FRONT STILL TOO LOW TO MENTION ANY TSTMS FOR NOW. EXPECT AT LEAST
MODERATE RAIN SHOWERS ALONG WITH IFR CIGS AND GUSTIER WINDS AT OR
BEFORE 19Z. LIGHT SRLY WINDS THIS MORNING WILL SLOWLY INCREASE
THROUGH THE DAY...WITH GUSTS DEVELOPING THIS AFTERNOON AND
STRENGTHENING TOWARD EVENING. EXPECT A RAPID RECOVERY TO VFR BY 06Z
WITH A DRY PUNCH WORKING IN POST FROPA.
AT KAVL...CIG LOWERING TREND THROUGH VFR IS ALREADY UNDERWAY THIS
MORNING...AND THE TRANSITION TO MVFR BY 15Z AND IFR BY 19Z HAS BEEN
MOVED UP ALONG WITH PRECIP TIMING IN UPGLIDE. WITH DAYBREAK TEMPS
AROUND 35 DEGREES...NO FREEZING RAIN IS CURRENTLY EXPECTED WITH THE
ONSET OF THE STEADIER RAIN. MVFR CIGS WILL TREND DOWN TO IFR THROUGH
LATE AFTN AS THE RAIN/SHOWERS INCREASE AND SRLY GUSTS DEVELOP. A
SHARP WIND SHIFT TO NW IS EXPECTED WITH FROPA BY 02Z...CREATING
WINDY CONDITIONS AND A GRADUAL MIXOVER TO SNOW SHOWERS TOWARD THE
END OF THE PERIOD.
ELSEWHERE...LOWERING VFR CLOUDS WILL TRANSITION QUICKLY TO MVFR FROM
S TO N AT THE FOOTHILL SITES THIS MORNING AS STEADIER LIGHT RAIN
SPREADS IN ON UPGLIDE. SHOWER COVERAGE/INTENSITY SHOULD INCREASE
THROUGH THE EARLY AFTERNOON...WITH ISOLD TO SCT TSTMS POSSIBLE OVER
SRN SECTIONS LATER THIS AFTN OR EARLY EVENING...ESPECIALLY NEAR
KAND. SRLY WINDS WILL INCREASE THROUGH THE AFTN AND BECOME
GUSTY...WITH A SHARP SHIFT WESTERLY DURING THE EVENING HOURS WITH
FROPA. A DRY SLOT ARRIVING FROM THE SW WILL ALLOW CIG CONDITIONS TO
IMPROVE AT THE UPSTATE TAF SITES...BUT WITH RESTRICTIONS LINGERING
AT KHKY THROUGH AT LEAST 06Z.
OUTLOOK...WINDY NW FLOW CONDITIONS WILL PERSIST WED INTO WED NIGHT
AS STRONG LOW PRES PULLS AWAY OFF THE MID ATLANTIC COAST. LINGERING
RESTRICTIONS AND NEARBY SHSN WILL CONTINUE TO IMPACT KAVL THROUGH
WED. STRONG DRY RIDGING WILL THEN DEVELOP THU THROUGH THE WEEKEND.
CONFIDENCE TABLE...
16-22Z 22-04Z 04-10Z 10-16Z
KCLT MED 68% MED 66% HIGH 93% HIGH 100%
KGSP MED 75% HIGH 82% HIGH 93% HIGH 100%
KAVL MED 70% HIGH 87% HIGH 100% HIGH 100%
KHKY MED 74% MED 63% HIGH 93% HIGH 100%
KGMU HIGH 83% MED 74% HIGH 93% HIGH 100%
KAND HIGH 85% MED 74% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST WEDNESDAY
NIGHT FOR NCZ501-503-505.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 6 AM EST
THURSDAY FOR NCZ033-048>052-058-059.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST
WEDNESDAY NIGHT FOR NCZ053-062.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...HG/SBK
SHORT TERM...NED
LONG TERM...JPT
AVIATION...HG/SBK
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS SPOKANE WA
944 PM PST Mon Mar 4 2013
.SYNOPSIS...
Clouds will be on the increase tonight as a low pressure system
moves toward the region. Light rain and snow will spread into the
Inland Northwest on Tuesday into Tuesday night. Wet snow accumulations
will be possible Tuesday and Tuesday night in north central and
northeast Washington. Cool and showery weather will persist into
Thursday, with the Wednesday Night and Thursday be the time window
when we`ll have the heaviest snow accumulations across the
northern Washington Zones. High pressure is expected to return
Friday, Saturday and Sunday, bringing dry weather and near normal
temperatures.
&&
.DISCUSSION...
Infrared satellite as of 830 pm indicated a large closed low
centered at 47N/136W with an occluded front just off the
Washington and Oregon coast inside 130W. Over the Inland Northwest
tonight the air mass is dry with dew points in the teens and lower
20s at most locations. This combined with an easterly pressure
gradient with the approaching system will keep winds elevated
at 5-15 mph through the Idaho Panhandle at Sandpoint and Coeur
D`Alene as well as the palouse. Winds will also be slightly elevated
at Spokane and through the Upper Columbia Basin. This combined
with increasing high clouds will reduce radiational cooling and keep
low temperatures from dropping to their potential.
Concerning the occluded front...models show some timing
differences as to when precipitation develops across Central
Washington tomorrow. The HRRR has precip just reaching Seattle at
9 am...while the GFS shows light precip as far east as Wenatchee
at this same time. With the GFS initializing too moist along the East
Slopes of the Cascades, it is likely that the atmosphere will take
some time to moisten up. With the NAM and ECMWF favoring a slower
precip onset...decided to lower POPs tomorrow morning for
Leavenworth, Wenatchee, and Omak. This may mean that afternoon
precipitation chances will need lowering over Eastern Washington.
However with ECMWF and HRRR indicating the potential for some
elevated showers developing ahead of the front with ECMWF showing
700-500mb Theta-e lapse rates near 0C/KM...will not make any
changes for Eastern Washington. A later onset of precipitation
over Central Washington may also mean temperatures getting a
little warmer than current forecast highs in these areas. However
will let mid shift look at this further. JW
&&
.AVIATION...
06Z TAFS: An occluded front off the Washington and Oregon Coast will
spread an increasing chance for -RASN in the valleys along the East
Slopes of the Cascades (including KEAT) Tuesday afternoon. The dry
low level air mass and the stretching and weakening nature of the
front as it moves east Tuesday afternoon and evening leads to lower
confidence of precipitation impacting the remaining TAF sites and
used VCSH to account for spotty light precipitation expected. CIGS
should remain VFR at all TAF sites...except KEAT where low level
upslope flow and expected -RASN may lower CIGS down to MVFR. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 27 42 34 44 31 43 / 0 20 40 70 50 30
Coeur d`Alene 24 46 33 44 31 43 / 0 20 40 70 60 30
Pullman 26 48 36 47 32 45 / 0 10 50 60 50 30
Lewiston 30 54 38 54 36 51 / 0 10 30 50 40 30
Colville 28 41 31 47 29 46 / 0 50 60 80 60 40
Sandpoint 24 39 32 41 31 40 / 0 40 40 70 70 50
Kellogg 23 45 32 42 31 39 / 0 20 60 70 70 40
Moses Lake 28 41 34 48 32 49 / 0 50 50 60 30 20
Wenatchee 30 38 32 43 32 48 / 0 60 60 60 30 20
Omak 30 35 30 41 29 44 / 0 70 60 80 60 50
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
859 PM PST Mon Mar 4 2013
.SYNOPSIS...
Clouds will be on the increase tonight as a low pressure system
moves toward the region. Light rain and snow will spread into the
Inland Northwest on Tuesday into Tuesday night. Wet snow accumulations
will be possible Tuesday and Tuesday night in north central and
northeast Washington. Cool and showery weather will persist into
Thursday, with the Wednesday Night and Thursday be the time window
when we`ll have the heaviest snow accumulations across the
northern Washington Zones. High pressure is expected to return
Friday, Saturday and Sunday, bringing dry weather and near normal
temperatures.
&&
.DISCUSSION...
Infrared satellite as of 830 pm indicated a large closed low
centered at 47N/136W with an occluded front just off the
Washington and Oregon coast inside 130W. Over the Inland Northwest
tonight the air mass is dry with dew points in the teens and lower
20s at most locations. This combined with an easterly pressure
gradient with the approaching system will keep winds elevated
at 5-15 mph through the Idaho Panhandle at Sandpoint and Coeur
D`Alene as well as the palouse. Winds will also be slightly elevated
at Spokane and through the Upper Columbia Basin. This combined
with increasing high clouds will reduce radiational cooling and keep
low temperatures from dropping to their potential.
Concerning the occluded front...models show some timing
differences as to when precipitation develops across Central
Washington tomorrow. The HRRR has precip just reaching Seattle at
9 am...while the GFS shows light precip as far east as Wenatchee
at this same time. With the GFS initializing too moist along the East
Slopes of the Cascades, it is likely that the atmosphere will take
some time to moisten up. With the NAM and ECMWF favoring a slower
precip onset...decided to lower POPs tomorrow morning for
Leavenworth, Wenatchee, and Omak. This may mean that afternoon
precipitation chances will need lowering over Eastern Washington.
However with ECMWF and HRRR indicating the potential for some
elevated showers developing ahead of the front with ECMWF showing
700-500mb Theta-e lapse rates near 0C/KM...will not make any
changes for Eastern Washington. A later onset of precipitation
over Central Washington may also mean temperatures getting a
little warmer than current forecast highs in these areas. However
will let mid shift look at this further. JW
&&
.AVIATION...
00Z TAFS: Expect increasing high level clouds overnight and a
strengthening easterly winds...especially for Pullman where winds
of 13-18 kts from the SE will be likely. A cold front currently
off the Pac Nw coast will move into, then through the Cascades
late tonight and Tues. Due to the dry air mass close to the sfc
(temp/dew pt temp spreads of 20-30F) we`re not fcstg any fog
overnight. Concerning the front Tues...only light rain or
rain/snow mix is expected for the KEAT and KMWH TAF sites.
Ceilings and vsbys should remain VFR with this pcpn as ceilings
lower to no lower than about 5000 ft msl. bz
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 27 42 34 44 31 43 / 0 20 40 70 50 30
Coeur d`Alene 24 46 33 44 31 43 / 0 20 40 70 60 30
Pullman 26 48 36 47 32 45 / 0 10 50 60 50 30
Lewiston 30 54 38 54 36 51 / 0 10 30 50 40 30
Colville 28 41 31 47 29 46 / 0 50 60 80 60 40
Sandpoint 24 39 32 41 31 40 / 0 40 40 70 70 50
Kellogg 23 45 32 42 31 39 / 0 20 60 70 70 40
Moses Lake 28 41 34 48 32 49 / 0 50 50 60 30 20
Wenatchee 30 38 32 43 32 48 / 0 60 60 60 30 20
Omak 30 35 30 41 29 44 / 0 70 60 80 60 50
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
343 PM CST TUE MAR 5 2013
.SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM.
THE INVERTED TROUGH AXIS STRETCHED FROM SURFACE LOW PRESSURE
CENTERED IN EASTERN KENTUCKY NORTHWESTWARD ACROSS NORTHERN IL AND
SOUTHEAST MN AT 3 PM THIS AFTERNOON. THE UPPER LOW OVER IOWA WILL
SHIFT SOUTHEAST OVER SOUTHERN IL AND THROUGH THE OHIO RIVER VALLEY
TONIGHT. THE BAND OF MODERATE TO HEAVY SNOW PARKED OVER SOUTHERN WI
FOR MOST OF THE DAY IS SLOWLY SHRINKING AND SLIPPING SOUTHWARD LATE
THIS AFTERNOON. DRY AIR FROM THE NORTHEAST IS PROGRESSING INTO THE
CENTRAL FORECAST AREA AND CAUSING RISING CLOUD HEIGHTS...INCREASED
VISIBILITIES AND MUCH SMALLER SNOW CRYSTALS. WE CUT BACK
SIGNIFICANTLY ON POPS AND EXPECTED ADDITIONAL SNOWFALL FOR THE REST
OF THE AFTERNOON AND EVENING DUE TO THIS DRY AIR.
WE CONTINUE TO SEE LIGHT RETURNS OVER SHEBOYGAN AND NORTHWARD ON
RADAR...AND SURFACE OBSERVATIONS CONTINUE TO SHOW NO WEATHER MEANING
THAT SNOW ALOFT IS NOT HITTING THE GROUND. RAP SOUNDINGS VERIFY THIS
BY SHOWING A DRY LAYER AROUND 5000 FEET. THERE IS A POSSIBILITY THAT
THIS DRY LAYER WILL SATURATE THIS EVENING AND SNOW COULD STILL
DEVELOP IN THE NORTHEAST FORECAST AREA...BUT AMOUNTS WILL BE LIGHT.
WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
THE SURFACE AND UPPER LOWS WILL MOVE EASTWARD OVERNIGHT AND
WEDNESDAY. HIGH RH AND LOW LEVEL CONVERGENCE ARE FORECAST TO SIT
ALONG THE LAKE MICHIGAN SHORELINE. DELTA TS WILL BE LESS THAN
9C...WHICH IS NOT FAVORABLE FOR MEASURABLE LAKE EFFECT SNOW. CUT
POPS AND CHANGED THE WEATHER TO SCATTERED FLURRIES FOR THE LAKESHORE
COUNTIES ON WED.
ELSEWHERE...WEAK CYCLONIC FLOW ALOFT WILL ALLOW FOR PLENTY OF CLOUDS
THROUGH THE DAY. CANNOT RULE OUT A FEW FLURRIES AS WELL. HIGH TEMPS
EXPECTED AROUND 30 AND A LITTLE WARMER NEAR THE LAKESHORE.
WEDNESDAY NIGHT THROUGH FRIDAY...
A MERIDIONAL FLOW IN THE SRN PORTION OF THE SPLIT JET STREAM OVER
THE UNITED STATES WILL RESULT IN UPPER RIDGING SLOWLY MOVING FROM
THE GREAT PLAINS TO THE MS RIVER VALLEY DURING THIS PERIOD. UPPER
TROUGHS OVER THE WESTERN AND EASTERN PORTIONS OF THE COUNTRY WILL
BE PRESENT DURING THIS TIME. THIS YIELDS A N-S POLAR HIGH PRESSURE
AREA OVER THE BADGER STATE. THE HIGH WILL MOVE EWD FOR FRIDAY WITH
LGT SLY WINDS AND WARM ADVECTION EXPECTED. BELOW NORMAL TEMPS ARE
EXPECTED WITH SOME WARMING FOR FRIDAY.
.LONG TERM...
SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE LOW TO MEDIUM
A LARGE UPPER LOW OVER THE DESERT SW ON SAT WILL TRACK INTO THE
CENTRAL PLAINS ON SUN AND THEN BETWEEN THE OHIO RIVER VALLEY AND
GREAT LAKES FOR EARLY NEXT WEEK. MODELS DIFFER ON EVOLUTION AND
TIMING BUT MILDER TEMPS WILL OCCUR WITH CHANCES OF RAIN/SNOW
THROUGH THIS PERIOD.
&&
.AVIATION/00Z TAFS/...
DRY AIR IS ERODING AWAY THE HIGHER SNOW RATES IN THE NORTH HALF OF
SOUTHERN WI AS WINDS TURN NORTHEAST. CIGS ARE RISING AND VSBYS ARE
IMPROVING. THIS AFFECTED MILWAUKEE AT 21Z AND EARLIER AT WAUKESHA.
THE BAND OF STEADY SNOW OVER MADISON IS EXPECTED TO SLIP SOUTH LATE
THIS AFTERNOON. NOT SURE IF THAT DRY AIR WILL AFFECT KENOSHA.
THE SNOW WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST THIS EVENING AND
DIMINISH FOR ALL BUT SOUTHEAST WI OVERNIGHT. CIGS/VSBYS WILL LIFT TO
MVFR...BUT CLOUDS SHOULD REMAIN WELL INTO WEDNESDAY.
WINDS BE GENERALLY NORTHEAST AND GUST AT TIMES TO 25KTS AT MKE AND
20KTS AT MADISON. LOOK FOR WINDS TO CONTINUE BACKING TO THE NORTH
THIS EVENING WITH WINDS GRADUALLY DIMINISHING TONIGHT. DRIFTING AND
POSSIBLY BLOWING SNOW CAN BE EXPECTED AT TIMES.
&&
.MARINE...SMALL CRAFT IN EFFECT THROUGH WEDNESDAY AFTERNOON EVENING
WITH PERSISTENT NNE WINDS AND HIGH WAVES. WINDS AND WAVES WILL
DIMINISH AS HIGH PRESSURE MOVES OVERHEAD BY THURSDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR WIZ064-
070>072.
WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR WIZ046-056-
057-062-063-067>069.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ047-
058-065-066.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM CST WEDNESDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL 4 PM CST WEDNESDAY FOR LMZ643-644.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...MRC
WEDNESDAY NIGHT THROUGH TUESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
245 AM EST THU MAR 7 2013
...DRY WEATHER AND SLOWLY WARMING TEMPS THE NEXT SEVERAL DAYS...
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THAT MUCH OF THE COUNTY IS
NOW BENEATH A BROAD LONGWAVE RIDGE EXTENDING FROM THE THE
CONTINENTAL DIVIDE EASTWARD TO THE UPPER MIDWEST/TN VALLEY. ON
EITHER SIDE OF THIS RIDGE WE FIND TROUGHING IN PLACE OVER THE
PACIFIC/NORTHWEST...AND ALSO TROUGHING/CLOSED UPPER LOW EXITING THE
MID-ATLANTIC TOWARD THE NORTHEASTERN STATES. OUR FORECAST AREA
RESIDES WITHIN A ZONE OF DEEP NW FLOW BETWEEN THE DEPARTING TROUGH
AND THE CENTRAL CONUS RIDGE. REGIONAL SOUNDING FROM THIS PAST
EVENING CONFIRM THE WATER VAPOR PRESENTATION THAT THE COLUMN OVER
THE FL PENINSULA IS EXTREMELY DRY. PW VALUES WERE GENERALLY WELL
UNDER HALF THE CLIMO VALUES FOR EARLY MARCH. THIS DRY AIR ALONG WITH
VIRTUALLY NO SYNOPTIC SUPPORT FOR LIFT IS RESULTING IN CLEAR SKIES
EARLY THIS MORNING.
AT THE SURFACE...WEDNESDAYS COLD FRONT IS NOW WELL SOUTH OF THE
PENINSULA WITH HIGH PRESSURE CENTERED ALONG THE MS VALLEY TRYING TO
RIDGE IN FROM THE NW. TEMPERATURES ARE COOL AS THE DRY ATMOSPHERE
HELPS WITH THE RADIATIVE PROCESS...HOWEVER THE GRADIENT IS TIGHT
ENOUGH SO FAR TO PREVENT MUCH IN THE WAY OF BOUNDARY LAYER
DE-COUPLING...EVEN UP NORTH. THIS LACK OF DE-COUPLING SHOULD
GENERALLY HELP KEEP TEMPS UP AND PREVENT MUCH FROST. IT IS STILL
POSSIBLE WITH THE RIDGE BUILDING THAT A BRIEF DECOUPLING COULD OCCUR
FOR OUR NORTHERN NATURE COAST ZONES TOWARD DAWN...ALLOWING A SHOT AT
BRIEFLY DROPPING DOWN TOWARD FREEZING.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY/TONIGHT...
QUIET...DRY AND COOL PERIOD THE NEXT 24-30 HOURS WITH TEMPERATURES
BELOW NORMAL FOR EARLY MARCH. FORECAST AREA WILL REMAIN EMBEDDED
WITHIN A DEEP LAYER NW FLOW PATTERN ON THE EASTERN PERIPHERY OF A
BUILDING/AMPLIFYING UPPER RIDGE. LOOKING FOR GENERALLY ABUNDANT
SUNSHINE TODAY...ESPECIALLY DURING THE MORNING HOURS. DURING THE
AFTERNOON AND EVENING WE MAY SEE SOME SCT HIGH LEVEL CIRRUS TO
FILTER THE SUN ARRIVING AS A WEAK UPPER LEVEL SHORTWAVE...NOW SEEN
IN WV IMAGE OVER THE LOWER MS VALLEY...TRACKS SOUTHEASTWARD TOWARD
THE REGION. THIS WEAK IMPULSE WILL EXIT TO OUR EAST LATE
TONIGHT/EARLY FRIDAY WITH ANY HIGH CIRRUS FOLLOWING INTO THE
ATLANTIC. HIGH TEMPS TODAY WILL REACH THE MID/UPPER 60S NORTH OF I-4
AND GENERALLY LOWER 70S FURTHER SOUTH. SOME AFTERNOON ONSHORE WIND
COMPONENT NEAR THE COAST IS LIKELY TO KEEP READINGS A FEW DEGREES
COOLER AT THE BEACHES...ESPECIALLY FROM MANATEE COUNTY NORTHWARD. A
DRY ATMOSPHERE AND SURFACE RIDGING STILL BUILDING IN FROM THE NORTH
WILL ALLOW FOR ANOTHER COOL OVERNIGHT PERIOD. ENOUGH RIDGING IS
LIKELY INTO THE NATURE COAST TO ALLOW FOR A POTENTIAL BRIEF
DECOUPLING TOWARD DAWN. THEREFORE A FEW NORMALLY COLDER SPOTS FROM
BROOKSVILLE NORTH MAY APPROACH FREEZING. SMALL DEWPOINT DEPRESSION
AND LIGHT WINDS BY THIS TIME SUGGEST FOR SOME PATCHY FROST
FORMATION. HAVE ADDED THIS POTENTIAL TO THE FORECAST GRIDS FOR
LOCATIONS FORECAST TO REACH 35 DEGREES OR LOWER. PATCHY FROST WILL
ALSO BE POSSIBLE FOR THE NORMALLY COLDER SPOTS WITHIN
HARDEE/DESOTO/HIGHLANDS COUNTIES...ALTHOUGH THESE AREAS ARE MORE
CONDITIONAL ON THE OCCURRENCE OF TRUE BOUNDARY LAYER DECOUPLING.
FRIDAY THROUGH SATURDAY...
VERY PLEASANT AND SEASONABLE CONDITIONS TO END THE WEEK WITH
TEMPERATURES RETURNING TO NORMAL...OR EVEN SLIGHTLY ABOVE NORMAL
DAYTIME READING BY SATURDAY AFTERNOON.
IMPRESSIVE MID/UPPER LEVEL RIDGE WILL CONTINUE TO AMPLIFY AND BUILD
EAST OVER-TOP THE FORECAST AREA. THIS STACKED RIDGING COMBINED WITH
THE SURFACE HIGH STILL RIDGING IN FROM THE NORTH WILL KEEP OUR AREA
PROTECTED WITH NEAR ZERO CHANCE OF RAIN INTO THE WEEKEND. HIGH TEMPS
WILL REBOUND NICELY ON FRIDAY AFTER THE COOL EARLY MORNING START.
SOME LOCATIONS MAY SEE A 35-40 DEGREE DIURNAL SWING. CURRENTLY
EXPECTING LOWER 70S NORTH AND MIDDLE 70S SOUTH. ONCE AGAIN...THE
POTENTIAL FOR A WEAK ONSHORE COMPONENT TO THE WIND DEVELOPING FOR
THE AFTERNOON MAY KEEP THE BEACHES A FEW DEGREES COOLER. LOW TEMPS
FRIDAY NIGHT WILL STILL BE COOL...BUT DO NOT ANTICIPATE ANY CHANCE
OF FREEZING TEMPS OR EVEN ANY FROST AS READING WARM 5-10 DEGREES
FROM THURSDAY NIGHT LOWS. HIGH TEMPERATURES SATURDAY WILL RESPOND TO
THIS LESS CHILLY START...AND THE MAXIMIZED HEIGHT
FIELDS/SUPPRESSION...TO EASILY REACH THE MIDDLE 70S NORTH AND
NEAR 80 IN THE SOUTH. LOW LEVEL SURFACE RIDGE TAKES A POSITION TO
OUR NORTH/NORTHEAST ON SATURDAY RESULTING IN STRONGER EASTERLY FLOW.
975-925MB BOUNDARY LAYER WINDS ARE FORECAST TO BE STRAIGHT EAST AT
10-15 KNOTS. 10-15 KNOTS SHOULD BE ENOUGH (GIVEN THE DEGREE OF
TERRESTRIAL WARMING) TO PREVENT ANY SEA-BREEZE CIRCULATION FROM
MOVING ONSHORE...AND ALLOW WARMER BEACH TEMPS THAN PREVIOUS DAYS.
ENJOY!
&&
.LONG TERM (SUNDAY THROUGH NEXT WEDNESDAY)...
DEEP LAYER RIDGING FROM THE GULF TO THE LOWER GREAT LAKES SAT NIGHT
SLOWLY TREKS EASTWARD...SLIDING OFF THE EASTERN SEABOARD MON. THIS
PROVIDES A DRY AIR MASS WITH INITIALLY NEAR NORMAL TEMPERATURES THAT
WARM SLIGHTLY. NORTH AND NE WINDS VEER TO SOUTHERLY BY MON AND MAY
BECOME ROBUST ON THE GULF AT TIMES.
FOR TUE AND WED...AN UPPER LEVEL LONG WAVE TROUGH WITH AN ATTENDANT
FRONTAL BOUNDARY MOVES INTO THE GULF-GREAT LAKES REGION THEN SHIFTS
OUT OVER THE ATLANTIC WED...SWEEPING THE FRONTAL BOUNDARY ACROSS THE
STATE MAINLY DURING THE DAY TUE. THE PORTION OF THE BOUNDARY MOVING
OVER THE AREA APPEARS RATHER WEAK AND WILL LIMIT PRECIPITATION TO
JUST SLIGHT CHANCE OF SHOWERS. WINDS SHIFT TO NORTHERLY IN THE WAKE
OF THE FRONT AND ARE EXPECT TO STAY BELOW ADVISORY SPEEDS.
TEMPERATURES COOL SLIGHT BUT STAY CLOSE TO NORMAL.
&&
.MARINE...
CAUTIONARY LEVEL NORTHERLY WINDS AWAY FROM THE SHORE WILL DIMINISH
BELOW 15 KNOTS BY MIDDAY. DUE TO RESIDUAL WAVE ACTION OBSERVED AT
REGIONAL BUOYS EARLY THIS MORNING...HAVE EXTENDED THE SMALL CRAFT
ADVISORY UNTIL MID-MORNING FOR THE OFFSHORE LEGS FROM BONITA BEACH
TO TARPON SPRINGS. ALL HEADLINES SHOULD THEN BE DROPPED FOR THE
AFTERNOON HOURS. BELOW HEADLINE CRITERIA WINDS AND SEAS ARE FORECAST
ACROSS THE EASTERN GULF THROUGH FRIDAY AFTERNOON AS HIGH PRESSURE
RIDGES IN FROM THE NORTH. THIS RIDGE WILL THEN TAKE UP A POSITION
FRIDAY NIGHT INTO EARLY SUNDAY THAT WILL BE FAVORABLE FOR THE
DEVELOPMENT OF NOCTURNAL/EARLY MORNING EASTERLY WINDS SURGES. THE
FORECAST WILL REFLECT THIS POTENTIAL WITH NEAR CAUTIONARY LEVEL
WINDS FRIDAY NIGHT. WINDS WILL DIMINISH FOR MUCH OF THE DAYLIGHT
HOURS OF SATURDAY...ONLY TO BUILD TO SOLID CAUTIONARY LEVELS LATER
SATURDAY EVENING AND NIGHT.
&&
.AVIATION...
VFR CONDITIONS FOR THE NEXT 24 HOURS WITH AFTERNOON CIRRUS. WINDS
NORTHEAST-NORTHWEST AT 10KT OR LESS.
&&
.FIRE WEATHER...
AN EXTENDED PERIOD OF CRITICALLY LOW RELATIVE HUMIDITY AWAY FROM THE
COAST IS EXPECTED FROM LATE THIS MORNING THROUGH THE EARLY EVENING
HOURS. ERC VALUES ARE ABOVE 37 FOR PINELLAS AND POLK
TODAY...HOWEVER ONLY POLK IS EXPECTED TO SEE THE CRITICAL DURATIONS
COINCIDENT WITH THE HIGH ERC. A RED FLAG WARNING HAS BEEN ISSUED FOR
POLK FOR THESE REASONS. ANOTHER DAY OF EXTENDED CRITICALLY LOW
RELATIVE HUMIDITY IS ANTICIPATED ON FRIDAY. THE POTENTIAL FOR ZONES
TO THAT ARE JUST UNDER ERC VALUES OF 37 TODAY TO RISE A FEW DIGITS
ON FRIDAY...HAS PROMPTED THE ISSUANCE OF A FIRE WEATHER WATCH FOR
POLK...PINELLAS... HIGHLANDS...AND LEE COUNTIES FRIDAY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 65 47 72 51 / 0 0 0 0
FMY 71 47 76 53 / 0 0 0 0
GIF 69 42 75 49 / 0 0 0 0
SRQ 66 45 72 52 / 0 0 0 0
BKV 67 34 71 42 / 0 0 0 0
SPG 65 50 72 57 / 0 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT UNTIL NOON EST TODAY FOR CHARLOTTE-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY
AFTERNOON FOR HIGHLANDS-LEE-PINELLAS-POLK.
RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR POLK.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD
TO TARPON SPRINGS OUT 20 TO 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
330 AM CST THU MAR 7 2013
.DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* POTENTIAL FOR MVFR CIGS THURSDAY AFTERNOON.
BMD
//DISCUSSION...UPDATED 06Z...
SHOULD BE A FAIRLY QUIET TAF PERIOD AS HIGH PRESSURE BUILDS ACROSS
THE AREA. RIDGE AXIS IS CENTERED ALONG THE MISSISSIPPI VALLEY LATE
THIS EVENING AND WILL SLOWLY SLIDE EAST THROUGH THE PERIOD. VFR
STRATUS DECK REMAINS IN PLACE ACROSS MOST OF NORTHERN ILLINOIS AND
SUSPECT WE WILL REMAIN LOCKED IN AS THERE IS NO SIGN OF THE BACK
EDGE ERODING SINCE SUNSET. GIVEN THE LATEST THOUGHTS ON STRATUS
REMAINING...REMOVED MENTION OF FOG FOR RFD. WILL HAVE TO MONITOR
THIS CLOSELY THOUGH AS DENSE FOG IS ALREADY FORMING WHERE SKIES HAVE
CLEARED OVER EASTERN IOWA. EXPECT THE STRATUS TO BEGIN ERODING FROM
THE WEST IN EARNEST AFTER DAYBREAK THURSDAY. ONCE WE GET UNDER MARCH
SUNSHINE...EXPECT SURFACE TEMPS TO WARM TO AROUND THE FREEZING MARK
WITH STEEP LOW LEVEL LAPSE RATES DEVELOPING. MODEL SOUNDINGS SHOW
POTENTIAL TO DEVELOP SOME MVFR CU/CASCU TUESDAY AFTERNOON...BUT
SIGNAL IS MIXED SO FOR NOW JUST INTRODUCED A SCT020 DECK. WINDS
SHOULD REMAIN RELATIVELY LIGHT...LESS THAN 10 KT THROUGH THE
PERIOD...TRENDING TO THE EAST THURSDAY EVENING BEHIND THE RIDGE
AXIS. BMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* LOW CONFIDENCE IN MVFR CIGS THURSDAY AFTERNOON.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z THURSDAY...UPDATED 00Z...
THURSDAY NIGHT THROUGH FRIDAY...VFR.
SATURDAY THROUGH SUNDAY...CHC RAIN.
SUNDAY...RAIN...MVFR.
SUNDAY NIGHT...RAIN AND SNOW...IFR LIKELY.
MONDAY...RAIN...MVFR LIKELY.
TUESDAY...VFR.
DZ
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
307 AM CST THU MAR 7 2013
.DISCUSSION...
ISSUED 307 AM CST THU MAR 7 2013
EARLY MORNING SURFACE MAP SHOWED HIGH PRESSURE RIDGING RUNNING THE
LENGTH OF THE MISSISSIPPI RIVER. RATHER TIGHT INVERSION JUST ABOVE
900 MB HAS PUT THE KIBOSH ON ANY REAL EROSION OF THE LARGE
STRATOCUMULUS DECK OVER MUCH OF THE MIDWEST...WITH ONLY AREAS
AROUND JACKSONVILLE SEEING ANY SUSTAINED CLEARING AND THAT HAS
BEGUN TO FILL IN AS WELL. THE CLOUDS HAVE KEPT TEMPERATURES IN THE
20S...WHICH IS GOOD SINCE CLEAR SKIES OVER THE SUBSTANTIAL SNOW
COVER IN THE NORTHERN CWA WOULD HAVE LIKELY RESULTED IN SINGLE
DIGITS AND TEENS IN THAT AREA. LOOKING UPSTAIRS...LATEST WATER
VAPOR IMAGERY SHOWING SEVERAL CIRCULATIONS IN A BROAD AREA OF 500
MB LOW PRESSURE OVER THE PACIFIC NORTHWEST. DEVELOPMENT OF THIS
PARTICULAR FEATURE WILL BE OF INTEREST TO OUR FORECAST FOR THE
WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY...
FAIRLY QUIET WEATHER EXPECTED IN THE SHORT TERM...AS THE HIGH
PUSHES EAST ACROSS THE GREAT LAKES. FORECAST SOUNDINGS SHOW THE
INVERSION SLOW TO ERODE THOUGH...SO WILL KEEP THE EASTERN CWA
FAIRLY CLOUDY TODAY AND TRY TO MARK SOME CLEARING ACROSS THE WEST
BY MIDDAY. MAIN CONCERN WILL BE WITH FOG POTENTIAL TONIGHT ACROSS
THE NORTH...WITH WINDS STILL FAIRLY LIGHT AND SOME POTENTIAL FOR
SNOW MELT TODAY. SHOULD SKIES STAY CLOUDY...THIS WOULD BE LESS OF
A CONCERN.
TEMPERATURE-WISE...WILL CONTINUE THE TREND OF KEEPING HIGHS A FEW
DEGREES COOLER ACROSS THE NORTH WHERE THE SNOW DEPTH RANGES FROM 5
TO 9 INCHES. HOWEVER...EVEN THESE AREAS MAY CRACK 40 BY FRIDAY...
WITH HIGHS 45-50 FURTHER SOUTH.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
UPPER LOW IN THE PACIFIC NORTHWEST SHOULD BETTER ORGANIZE AS IT
DROPS SOUTHWARD ALONG THE CALIFORNIA COAST TONIGHT AND FRIDAY.
LATEST MODEL GUIDANCE CONTINUES TO EJECT THIS FEATURE NORTHEAST
THIS WEEKEND...AS A DEEPENING SHORTWAVE TRACKS EAST ACROSS THE
CANADIAN PRAIRIES. SOME PHASING OF THE TWO FEATURES IS INDICATED
LATER THIS WEEKEND OVER THE CENTRAL U.S. AND THIS WILL
SIGNIFICANTLY INCREASE PRECIP CHANCES AS THE WEEKEND PROGRESSES.
GOOD MOISTURE SURGE SHOULD TAKE PLACE AHEAD OF THIS PHASING...
WITH GFS PRECIPITABLE WATER VALUES OF 1.25 INCHES SATURDAY NIGHT
NEAR THE 99TH PERCENTILE FOR EARLY MARCH. WOULD NOT BE SURPRISED
TO SEE OVER AN INCH OF RAIN IN SOME AREAS SATURDAY NIGHT THROUGH
SUNDAY NIGHT. HAVE INTRODUCED CATEGORICAL RAIN CHANCES SATURDAY
NIGHT NORTHWEST OF THE ILLINOIS RIVER...AND ALSO ADDED AREAS OF
FOG ACROSS THE NORTHERN CWA DUE TO THE HEAVIER RAIN AND RAPID SNOW
MELT. SUNDAY WILL START OUT RATHER WET AS WELL. HOWEVER...THE
MODELS BEGIN TO DIVERGE IN TERMS OF WHETHER A DRY SLOT MAY SPREAD
IN DURING THE DAY. WITH THE DIVERSITY...WILL NOT TRY TO GET TOO
CUTE WITH SPLITTING OUT MORNING AND AFTERNOON PERIODS.
TEMPERATURES BOTH DAYS SHOULD REACH WELL INTO THE 50S.
SUNDAY NIGHT AND MONDAY...THE GFS AND ECMWF MODELS BOTH SHOW THE
NORTHERN WAVE EXITING THE AREA...WHILE ANOTHER LOW DEVELOPS OVER
THE SOUTHERN PLAINS. THE GFS IS MORE AGGRESSIVE WITH CLOSING THIS
LOW OFF AND LIFTING IT NORTHEAST...WHILE THE ECMWF WEAKENS BACK
INTO AN OPEN WAVE. LEANING MORE TOWARD THE ECMWF SOLUTION FOR
NOW...AND HAVE LIMITED LIKELY POPS SUNDAY NIGHT TO THE SOUTHEAST
THIRD OF THE CWA. HAVE KEPT SOME PRECIP CHANCES IN ON MONDAY FOR
NOW...BUT CONFIDENCE IS LOW AT THE MOMENT. HAVE LARGELY KEPT THE
PRECIP AS RAIN EXCEPT FOR A MIX IN THE NORTHWEST.
MODEL AGREEMENT DOES NOT IMPROVE AS THE WEEK PROGRESSES...WITH THE
LONGER RANGE SOLUTIONS VARYING WITH THE STRENGTH OF ANOTHER WAVE
DROPPING INTO THE GREAT LAKES ON TUESDAY. THE ECMWF SOLUTION WOULD
BE MUCH COOLER FOR US WITH SIGNIFICANT RIDGING WEST OF THE
ROCKIES. FOR NOW HAVE KEPT TEMPERATURES ABOUT 5 DEGREES BELOW
NORMAL FOR THE END OF THE FORECAST PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 1150 PM CST WED MAR 6 2013
BROKEN TO OVERCAST MVFR CEILINGS OF 1.5-2.5K FT TO PREVAIL DURING
OVERNIGHT ACROSS THE CENTRAL IL TERMINAL AIRPORTS...AS STRONG
INVERSION FROM 900-750 MB TRAPS LOW LEVEL MOISTURE/CLOUDS (1-2K FT
THICK) WITH WEAK NNW FLOW. USED RAP MODEL 925-850 MB RH FIELD FOR
SCATTERING OUT THIS LOW CLOUD DECK FIRST AT SPI AND PIA BETWEEN
11-13Z AND LAST AT CMI AFTER 16Z THU. COULD BE VSBYS OF 4-6 MILES AS
CLOUDS SCATTER OUT THU MORNING. ALSO HAVE REPORTS OF FLURRIES PAST
FEW HOURS AT CMI AND COULD BE A CHANCE OF FLURRIES OVERNIGHT
MAINLY ALONG I-74 TAF SITES. NW WINDS OF 5-10 KTS TO DIMINISH
LIGHT DURING OVERNIGHT AND VEER NORTHERLY. LIGHT AND VARIABLE WINDS
EXPECTED THU AS 1030 MB HIGH PRESSURE RIDGE FROM EASTERN MN/IA AND
INTO MO DRIFTS EAST ACROSS IL BY 18Z/NOON THU.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1152 PM CST WED MAR 6 2013
.DISCUSSION...
ISSUED 900 PM CST WED MAR 6 2013
UPDATED THE FORECAST TO KEEP LOW CLOUDS IN THE FORECAST LONGER
TONIGHT AND ALSO NUDGE LOW TEMPERATURES UP A BIT DUE TO LINGERING
LOW CLOUDS. MOSTLY CLOUDY TO OVERCAST SKIES TONIGHT EXCEPT LESS
CLOUD COVER OVER 4 SW COUNTIES OF SCHUYLER...SCOTT...CASS AND
MORGAIN FROM JACKSONVILLE SW. LOWS IN THE LOW TO MID 20S EXPECT
SOME UPPER TEENS FROM GALESBURG TO JACKSONVILLE WEST. NW WINDS
5-10 MPH TURNING LIGHT NNW LATER TONIGHT.
OVERCAST LOW CLOUDS FROM 1.5-3K FT BLANKET MUCH OF CENTRAL AND NE
IL INTO SE IA/WI AT MID EVENING WITH CLEARING SW OF JACKSONVILLE.
CLOUD LAYER IS ABOUT 1-2 K FT THICK PER KILX/KDVN SOUNDINGS AND
PILOT REPORTS THIS EVENING. 00Z KILX SOUNDING SHOWS STRONG
INVERSION FROM JUST ABOVE 900 MB TO 750 MB SO THIS IS TRAPPING LOW
LEVEL MOISTURE/CLOUDS OVER CENTRAL/SE IL TONIGHT WITH LIGHTER
FLOW. RAP MODEL 925-850 MB RH CAPTURING THIS CLOUD FIELD WELL
WHICH KEEPS ABUNDANT LOW CLOUDS OVER CENTRAL AND SE THROUGH THE
NIGHT WITH SOME DECREASING OF LOW CLOUDS FROM PEORIA TO
TAYLORVILLE LATER TONIGHT AND INTO EASTERN IL DURING THU MORNING
AS 1030 MB HIGH PRESSURE RIDGE OVER MN INTO CENTRAL IA/MO DRIFTS
EAST ACROSS THE MS VALLEY INTO IL THU. A LIGHT FOG COULD DEVELOP
OVER WEST CENTRAL AND NW IL LATER TONIGHT WHERE LESS LOW CLOUDS AND
LIGHTER NNW WINDS PREVAIL.
07
&&
.AVIATION...
ISSUED 1150 PM CST WED MAR 6 2013
BROKEN TO OVERCAST MVFR CEILINGS OF 1.5-2.5K FT TO PREVAIL DURING
OVERNIGHT ACROSS THE CENTRAL IL TERMINAL AIRPORTS...AS STRONG
INVERSION FROM 900-750 MB TRAPS LOW LEVEL MOISTURE/CLOUDS (1-2K FT
THICK) WITH WEAK NNW FLOW. USED RAP MODEL 925-850 MB RH FIELD FOR
SCATTERING OUT THIS LOW CLOUD DECK FIRST AT SPI AND PIA BETWEEN
11-13Z AND LAST AT CMI AFTER 16Z THU. COULD BE VSBYS OF 4-6 MILES AS
CLOUDS SCATTER OUT THU MORNING. ALSO HAVE REPORTS OF FLURRIES PAST
FEW HOURS AT CMI AND COULD BE A CHANCE OF FLURRIES OVERNIGHT
MAINLY ALONG I-74 TAF SITES. NW WINDS OF 5-10 KTS TO DIMINISH
LIGHT DURING OVERNIGHT AND VEER NORTHERLY. LIGHT AND VARIABLE WINDS
EXPECTED THU AS 1030 MB HIGH PRESSURE RIDGE FROM EASTERN MN/IA AND
INTO MO DRIFTS EAST ACROSS IL BY 18Z/NOON THU.
07
&&
.PREV DISCUSSION...
ISSUED 231 PM CST WED MAR 6 2013
MODELS IN REASONABLE AGREEMENT OVER THE 7-DAY PERIOD...PARTICULARLY
GIVEN THE PRIMARY ENERGY TO IMPACT ILLINOIS THIS WEEKEND IS
RELATIVELY POORLY SAMPLED OFF THE PACIFIC COAST.
SHORT TERM...TONIGHT THROUGH SATURDAY
STORM SYSTEM THAT BROUGHT SNOW TO FORECAST AREA YESTERDAY IS NOW
ALONG THE MID-ATLANTIC COAST AND CONTINUES TO DIMINISH ITS IMPACT ON
ILLINOIS AS HIGH PRESSURE OVER MID-MISSOURI VALLEY PUSHES EASTWARD.
PLENTIFUL CLOUDINESS PERSISTS TO THE EAST OF THE RIDGE AXIS AND
WILL ONLY GRADUALLY DIMINISH AS THE RIDGE PUSHES EAST TONIGHT.
WILL HAVE TO MONITOR CLOSELY AS DEVELOPING BREAKS MAY LEAD TO
LOWER TEMPS THAN FORECAST IN SNOW COVERED AREAS AS WELL AS A
POTENTIAL FOR FOG...PARTICULARLY WESTERN COUNTIES.
THERE HAS BEEN SOME SNOW MELT/COMPACTION TODAY IN OCCASIONAL SUNSHINE
DESPITE THE COLD TEMPERATURES. HAVE TEMPERED TOMORROWS HIGH
FORECAST A TAD GIVEN THE IMPACT OF THE REMAINING SNOW...BUT WITH
MARCH SUN AND RAPIDLY RISING 850 TEMPS...FEEL SNOW MAY ONLY HAVE A
MINOR IMPACT ON FRIDAYS TEMPS AND SHOULD BE GONE BY SATURDAY. WITH
LIGHT WINDS IN PLACE WITH DEEP RIDGING WILL HAVE TO MONITOR
CONDITIONS FOR POTENTIAL OF FOG BOTH THURSDAY AND FRIDAY NIGHTS.
BY SATURDAY AFTERNOON SOUTHEAST WINDS AND 850 TEMPERATURES
INCREASING TO AROUND 10C SHOULD SUPPORT HIGHS REACHING INTO THE
50S.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
STRONG SYSTEM CURRENTLY OFF THE NW PACIFIC COAST IS PROGGED TO PLUNGE
INTO THE SW U.S. AND THEN APPROACH ILLINOIS BY SATURDAY NIGHT.
WITH THIS SHIFT TO MORE OF PACIFIC STORM TRACK...PRECIP WITH THIS
NEXT SYSTEM SHOULD BE MOSTLY RAIN. ENERGY IS EXPECTED TO BE
EJECTED TOWARD US IN A PIECEMEAL FASHION PROVIDING US WITH SEVERAL
WAVES OF PRECIP INTO MONDAY. RAINFALL AMOUNTS MAY BE
SIGNIFICANT...PARTICULARLY IN OUR NORTHERN COUNTIES WHERE SNOWMELT
RUNOFF WILL CONTRIBUTE. PRECIP WATER FORECASTS FROM THE GFS HAVE
VALUES AS HIGH AS 1.15 INCHES LATE SATURDAY NIGHT WHICH IS 2+ SD
ABOVE NORMAL FOR MARCH. TOTAL 48-HOUR AMOUNTS MAY LOCALLY APROACH
2 INCHES.
SOME COLDER AIR FILTERS IN BEHIND THE LOW ON MONDAY...BUT BOUNDARY
LAYER TEMPS AT THIS POINT SUGGEST THAT THE PRECIP MAY ONLY
BRIEFLY MIX WITH OR CHANGE TO SNOW BEFORE ENDING.
IN WAKE OF SYSTEM...TEMPS SHOULD BE 5-10 DEGREES BELOW NORMAL
THROUGH WEDNESDAY. COLDER TEMPS SHOULD REMAIN NORTH OF THE AREA
WITH HIGH ZONAL COMPONENT UPPER LEVEL FLOW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1123 PM CST WED MAR 6 2013
.AVIATION...
A DIFFICULT CLEARING TREND WILL DOMINATE THE AVIATION FORECAST
EARLY TODAY OVER SOUTHEAST IOWA AND NEAR MLI...WITH CLEARING POSSIBLY
DELAYED UNTIL 12 TO 15Z. THE CIGS REMAIN MVFR
AROUND 1800 FT. WHILE CID AND DBQ ARE CLEAR...THEY WILL SEE A RISK
OF IFR TO LIFR FOG AND VV002 STRATUS DEVELOPMENT THROUGH
SUNRISE...MLI AND BRL SHOULD REMAIN CLOUDY ENOUGH THAT FOG DOES
NOT BECOME AN ISSUE. VERY LIGHT WINDS WILL LAST THROUGH THURSDAY
EVENING.
&&
.PREV DISCUSSION... /ISSUED 541 PM CST WED MAR 6 2013/
UPDATE...
SHORT TERM MODELS INCLUDING THE HRRR AND RAP13 CONTINUE TO
REPRESENT THE STRATUS FIELD BEST...AND BOTH SUGGEST IT WILL HANG
ON ALL NIGHT. AS SEEN ON SATELLITE TRENDS SINCE 430 PM...THE EDGE
OF THE STRATUS IS NO LONGER MOVING/DISSIPATING. IF IT IS...IT IS
NOW EXCRUCIATINGLY SLOW.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
252 AM MST THU MAR 7 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 248 AM MST THU MAR 7 2013
A RIDGE WILL BE OVER THE PLAINS TODAY AND TONIGHT AND THEN SHIFT
EAST FRIDAY. SOUTHWEST FLOW WILL BE OVER THE CENTRAL PLAINS FRIDAY
NIGHT WITH AN UPPER LOW OVER NORTHERN ARIZONA. THE UPPER LOW WILL
MOVE INTO SOUTHEAST COLORADO SATURDAY AND INTO SOUTHEAST NEBRASKA
SATURDAY NIGHT. A SURFACE TROUGH WILL MOVE INTO EASTERN COLORADO
TODAY AND TONIGHT. BY FRIDAY A LARGE AREA OF LOW PRESSURE WILL
RESIDE OVER THE ROCKIES. A SURFACE LOW WILL BE CENTERED OVER EASTERN
COLORADO/NORTHWEST FRIDAY NIGHT AND SATURDAY. THE LOW WILL SHIFT
INTO NORTHEAST KANSAS SATURDAY NIGHT.
DRY WEATHER WILL CONTINUE TODAY THROUGH FRIDAY. BOUNDARY LAYER RH
ABOVE 90 PERCENT WILL BE FAVORABLE FOR FOG DEVELOPMENT TONIGHT
AND EARLY FRIDAY MORNING ACROSS MOST OF THE FA. DYNAMICS START
AFFECTING THE FA FRIDAY NIGHT BUT MOISTURE IS MARGINAL. THE GFS
SHOWS A DRY SLOT OVERTAKING NEARLY ALL OF THE FA FRIDAY NIGHT
EXCEPT FOR THE FAR NORTHWEST ZONES. FOR THIS REASON HAVE LOWERED
POPS SOME. INSTABILITY DOES NOT LOOK AS WIDESPREAD SO HAVE KEPT
THAT EAST OF THE COLORADO BORDER. FORECAST SOUNDINGS INDICATE SOME
STRATUS AND POSSIBLY FOG MAINLY ACROSS THE NORTHEAST ZONES. THE
DRY SLOT CONTINUES TO AFFECT THE FA SATURDAY MORNING SO HAVE
REDUCED POPS SOME. THE DRY SLOT SHIFTS EAST OF THE FA SATURDAY
AFTERNOON. GOOD MOISTURE MOVES INTO THE FA SO PLAN TO KEEP CURRENT
HIGH CHANCE AND LIKELY POPS. ISOLATED THUNDER WILL REMAIN IN THE
FORECAST BUT WILL SLOWLY SHIFT INTO THE EASTERN FA BY AFTERNOON.
WRAPAROUND SNOW WILL SPREAD ACROSS THE ENTIRE FA SATURDAY NIGHT.
WINDS WILL BE STRONG ENOUGH FOR BLOWING SNOW AS WELL. AT THIS TIME
IT APPEARS THAT TOTAL SNOW AMOUNTS SHOULD VARY AROUND 3 INCHES FOR
THE EVENT. SNOW SHOULD START DECREASING SOME LATE SATURDAY NIGHT.
MAX TEMPERATURES SHOULD RISE INTO THE LOWER TO MID 60S TODAY OVER
THE SOUTHWEST HALF OF THE FA WITH LOWER 50S IN THE EXTREME NORTHEAST
FA. TEMPERATURES FRIDAY WILL BE COOLER WITH READINGS IN THE MID 50S.
THE WEST WILL BE COLDER WITH UPPER 30S AND THE SOUTHEAST WILL REACH
INTO THE LOWER 50S. MIN TEMPERATURES TONIGHT WILL BE IN THE UPPER
20S/LOWER 30S. LOWS FRIDAY NIGHT WILL BE EVEN WARMER WITH READINGS
IN THE UPPER 30S WEST TO LOWER 40S EAST. LOW TEMPERATURES SATURDAY
NIGHT WILL BE IN THE MID AND UPPER 20S.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 1147 PM MST WED MAR 6 2013
SNOW WILL BE WINDING DOWN ON SUNDAY WITH ADDITIONAL ACCUMULATIONS
OF LESS THAN AN INCH EXPECTED. HOWEVER...NORTHERLY WINDS WILL BE
GUSTY AND RESULT IN AREAS OF BLOWING SNOW. SNOW WILL END BY SUNDAY
NIGHT. THE REMAINDER OF THE PERIOD WILL BE DOMINATED BY UPPER
RIDGING BUILDING ACROSS THE ROCKIES...RESULTING IN DRY CONDITIONS
AND WARMING TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1030 PM MST WED MAR 6 2013
POTENTIAL FOR OVERNIGHT FOG/STRATUS CONTINUES...WITH BEST CHANCES
FOR REDUCTIONS IN FLIGHT CATEGORIES AT MCK. CONFIDENCE SOMEWHAT
LOW ATTM THOUGH AS 00Z RAOBS AND RAP DATA LOWER CONFIDENCE IN HOW
WIDESPREAD FOG POTENTIAL WILL BE. FOR THE TIME BEING...BROUGHT MCK
DOWN TO MIDDLE OF THE ROAD/OPERATIONAL SIGNIFICANT MVFR FOR A
PORTION OF THE OVERNIGHT HOURS. OTHERWISE...VFR CONDITIONS
EXPECTED FOR THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...032
LONG TERM...024
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1150 PM MST WED MAR 6 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 218 PM MST WED MAR 6 2013
AS OF 3 PM CST...2 PM MST...SKIES WERE MOSTLY CLEAR TO PARTLY CLOUDY
AS SOME HIGH LEVEL CIRRUS MOVES FROM WEST TO EAST. TEMPERATURES
RANGED FROM THE LOW 40S NEAR NORTON...KANSAS TO NEAR 60 DEGREES IN
TRIBUNE...KANSAS. WINDS WERE GENERALLY FROM THE SOUTHEAST AT 15 TO
20 MPH WITH GUSTS UP TO 25 OR 30 MPH. A LEE TROUGH WAS DEVELOPING
ACROSS EAST CENTRAL COLORADO.
FOR TONIGHT...BREEZY SOUTHEAST WINDS WILL WEAKEN THIS EVENING. WINDS
WILL BACK TO THE EAST OVER THE EASTERN FORECAST AREA...ALLOWING AIR
WITH HIGHER MOISTURE CONTENT TO FILTER INTO THE AREA. LOW
TEMPERATURES WILL DROP INTO THE LOW 20S. WITH LIGHT WINDS...HIGHER
DEWPOINTS AND COLD TEMPERATURES...FOG IS EXPECTED TO DEVELOP ACROSS
A LARGE AREA TONIGHT. ACROSS THE WESTERN FORECAST AREA...A LEE
TROUGH TO THE WEST WILL MOVE TO THE EAST. WINDS WILL BE LIGHT AND
VARIABLE JUST EAST OF THE TROUGH AND FROM THE WEST OR NORTHWEST AT
5-10 MPH AS THE TROUGH MOVES IN. THIS SHOULD KEEP THE FOG FROM
ADVANCING INTO EASTERN COLORADO. FOG COULD BE DENSE...BUT WAS NOT
CONFIDENT ENOUGH TO PLACE THIS INTO THE FORECAST AT THE CURRENT TIME.
TEMPERATURES WILL BE HIGHLY VARIABLE ACROSS THE FORECAST AREA FOR
TOMORROW. HIGHS ACROSS MOST OF EASTERN COLORADO AND PORTIONS OF
NORTHWEST KANSAS WILL BE IN THE MID 60S TO NEAR 70 IN SOME SPOTS.
FOG AND CLOUDS WILL LINGER INTO THE LATE MORNING HOURS FOR NORTHEAST
PORTIONS OF THE FORECAST AREA. THIS WILL KEEP HIGH TEMPERATURES
CONFINED TO THE LOWER 50S NEAR MCCOOK NEBRASKA AND HILL CITY KANSAS.
LIGHT AND VARIABLE WINDS IN THE MORNING WILL BECOME SOUTHEAST AT 10
TO 15 MPH DURING THE AFTERNOON HOURS.
AT THIS TIME...FIRE WEATHER IS NOT EXPECTED TO BECOME A CONCERN FOR
TOMORROW. RELATIVE HUMIDITIES WILL DROP INTO THE 15 TO 25 PERCENT
RANGE FOR CHEYENNE AND KIT CARSON COUNTIES IN COLORADO AND
SHERMAN...WALLACE AND GREELEY COUNTIES IN KANSAS. HOWEVER...LIGHT
WINDS ARE EXPECTED WHICH WILL REDUCE THE FIRE WEATHER DANGER FOR
TOMORROW AFTERNOON.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 1147 PM MST WED MAR 6 2013
SNOW WILL BE WINDING DOWN ON SUNDAY WITH ADDITIONAL ACCUMULATIONS
OF LESS THAN AN INCH EXPECTED. HOWEVER...NORTHERLY WINDS WILL BE
GUSTY AND RESULT IN AREAS OF BLOWING SNOW. SNOW WILL END BY SUNDAY
NIGHT. THE REMAINDER OF THE PERIOD WILL BE DOMINATED BY UPPER
RIDGING BUILDING ACROSS THE ROCKIES...RESULTING IN DRY CONDITIONS
AND WARMING TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1030 PM MST WED MAR 6 2013
POTENTIAL FOR OVERNIGHT FOG/STRATUS CONTINUES...WITH BEST CHANCES
FOR REDUCTIONS IN FLIGHT CATEGORIES AT MCK. CONFIDENCE SOMEWHAT
LOW ATTM THOUGH AS 00Z RAOBS AND RAP DATA LOWER CONFIDENCE IN HOW
WIDESPREAD FOG POTENTIAL WILL BE. FOR THE TIME BEING...BROUGHT MCK
DOWN TO MIDDLE OF THE ROAD/OPERATIONAL SIGNIFICANT MVFR FOR A
PORTION OF THE OVERNIGHT HOURS. OTHERWISE...VFR CONDITIONS
EXPECTED FOR THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...024
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1032 PM MST WED MAR 6 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 218 PM MST WED MAR 6 2013
AS OF 3 PM CST...2 PM MST...SKIES WERE MOSTLY CLEAR TO PARTLY CLOUDY
AS SOME HIGH LEVEL CIRRUS MOVES FROM WEST TO EAST. TEMPERATURES
RANGED FROM THE LOW 40S NEAR NORTON...KANSAS TO NEAR 60 DEGREES IN
TRIBUNE...KANSAS. WINDS WERE GENERALLY FROM THE SOUTHEAST AT 15 TO
20 MPH WITH GUSTS UP TO 25 OR 30 MPH. A LEE TROUGH WAS DEVELOPING
ACROSS EAST CENTRAL COLORADO.
FOR TONIGHT...BREEZY SOUTHEAST WINDS WILL WEAKEN THIS EVENING. WINDS
WILL BACK TO THE EAST OVER THE EASTERN FORECAST AREA...ALLOWING AIR
WITH HIGHER MOISTURE CONTENT TO FILTER INTO THE AREA. LOW
TEMPERATURES WILL DROP INTO THE LOW 20S. WITH LIGHT WINDS...HIGHER
DEWPOINTS AND COLD TEMPERATURES...FOG IS EXPECTED TO DEVELOP ACROSS
A LARGE AREA TONIGHT. ACROSS THE WESTERN FORECAST AREA...A LEE
TROUGH TO THE WEST WILL MOVE TO THE EAST. WINDS WILL BE LIGHT AND
VARIABLE JUST EAST OF THE TROUGH AND FROM THE WEST OR NORTHWEST AT
5-10 MPH AS THE TROUGH MOVES IN. THIS SHOULD KEEP THE FOG FROM
ADVANCING INTO EASTERN COLORADO. FOG COULD BE DENSE...BUT WAS NOT
CONFIDENT ENOUGH TO PLACE THIS INTO THE FORECAST AT THE CURRENT TIME.
TEMPERATURES WILL BE HIGHLY VARIABLE ACROSS THE FORECAST AREA FOR
TOMORROW. HIGHS ACROSS MOST OF EASTERN COLORADO AND PORTIONS OF
NORTHWEST KANSAS WILL BE IN THE MID 60S TO NEAR 70 IN SOME SPOTS.
FOG AND CLOUDS WILL LINGER INTO THE LATE MORNING HOURS FOR NORTHEAST
PORTIONS OF THE FORECAST AREA. THIS WILL KEEP HIGH TEMPERATURES
CONFINED TO THE LOWER 50S NEAR MCCOOK NEBRASKA AND HILL CITY KANSAS.
LIGHT AND VARIABLE WINDS IN THE MORNING WILL BECOME SOUTHEAST AT 10
TO 15 MPH DURING THE AFTERNOON HOURS.
AT THIS TIME...FIRE WEATHER IS NOT EXPECTED TO BECOME A CONCERN FOR
TOMORROW. RELATIVE HUMIDITIES WILL DROP INTO THE 15 TO 25 PERCENT
RANGE FOR CHEYENNE AND KIT CARSON COUNTIES IN COLORADO AND
SHERMAN...WALLACE AND GREELEY COUNTIES IN KANSAS. HOWEVER...LIGHT
WINDS ARE EXPECTED WHICH WILL REDUCE THE FIRE WEATHER DANGER FOR
TOMORROW AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 205 PM MST WED MAR 6 2013
THURSDAY NIGHT-FRIDAY...UPPER LOW CENTER JUST OFF THE CALIFORNIA
COAST AT THE BEGINNING OF THE PERIOD MOVING SOUTHEAST TOWARD THE
SOUTHERN TIP OF CALIFORNIA/SOUTHWEST ARIZONA AREA BY 00Z SATURDAY.
AT THE SURFACE LOW PRESSURE SLOWLY DEEPENS IN SOUTHEAST COLORADO
THROUGH THE PERIOD. STRATUS/FOG EXPECTED ACROSS THE NORTHEAST 1/2 OF
THE AREA MID THURSDAY NIGHT EXPANDING SOUTHWESTWARD BY 12Z FRIDAY AS
WINDS TURN NORTHEAST IN RESPONSE TO DEEPENING LOW. STRATUS/FOG
SHOULD RETREAT NORTH AND EAST FRIDAY AFTERNOON BUT COULD STILL POSE
A PROBLEM ACROSS THE FAR EAST AND NORTHEAST WHERE BOUNDARY LAYER RH
STILL HIGH. OTHERWISE SHOULD SEE AN INCREASE IN CLOUDINESS MOVING IN
FROM THE SOUTHWEST AHEAD OF UPPER LOW. NOT TERRIBLY CONFIDENT IN
PRECIPITATION CHANCES FRIDAY BUT ALSO CANT RULE IT OUT EITHER. HAVE
KEPT SLIGHT CHANCE POPS GOING FOR NOW. THERE IS SOME INSTABILITY
THAT MOVES IN FROM THE SOUTH DURING THE AFTERNOON AS WELL AS NOSE OF
UPPER JET. WILL KEEP THUNDER MENTION GOING AS WELL. LOWS MID 20S
TO LOW 30S WITH HIGHS LOW TO MID 50S NORTH OF I-70...UPPER 50S TO
MID 60S SOUTH.
FRIDAY NIGHT-SATURDAY...12Z GFS/NAM/09Z SREF BRING UPPER LOW OVER
FORECAST AREA BY 00Z SUNDAY WITH 00Z ECWMF A BIT SLOWER OVER NORTH
CENTRAL NEW MEXICO. FOR FRIDAY NIGHT MID LEVEL DRY SLOT TRIES TO
WORK ITS WAY INTO THE AREA AFTER MIDNIGHT WITH BETTER PRECIPITATION
CHANCES GENERALLY NORTH OF INTERSTATE 70 AND BETTER ALONG THE
NEBRASKA/KANSAS BORDER. PREVIOUS FORECAST HAD THE GENERAL IDEA JUST
TWEAKED POPS DOWN A BIT WHERE CONFIDENCE HIGHER IN WHERE DRY SLOT
WOULD BE. STRATUS/FOG WILL BE A CONCERN AS WELL AND ADDED TO
FORECAST. UPPER JET OVER THE AREA WITH GOOD DIVERGENCE. STILL SOME
WEAK INSTABILITY OVER THE AREA SO HAVE ALSO KEPT SMALL CHANCE FOR
THUNDERSTORMS. FOR SATURDAY SFC LOW MOVES INTO CENTRAL OR SOUTHWEST
KANSAS DEPENDING ON THE MODEL CHOICE. DRY SLOT WORKS ITS WAY EAST
LIMITING PRECIP POTENTIAL WHILE FURTHER WEST/NORTHWEST WRAPAROUND
PRECIPITATION MOVES IN. LOWERED POPS A BIT WHERE DRY SLOT EXPECTED
BUT WITH DIFFERENCES IN OPINION MODEL WISE DIDNT GET TOO SPECIFIC AS
CONFIDENCE NOT TERRIBLY HIGH. DEFINING RAIN/SNOW LINE ALSO DEPENDENT
ON SFC LOW LOCATION AND EXTENT OF WRAPAROUND PRECIP. AGAIN WILL TRY
AND BLEND MODEL SOLUTIONS FOR NOW. LOW TEMPERATURES MILD IN THE
MID 30S TO MID 40S. HIGHS SATURDAY LOW 40S FAR NORTHWEST...50-60
ELSEWHERE...WARMEST FROM HILL CITY TO LEOTI.
SATURDAY NIGHT-SUNDAY NIGHT...MODELS COMING INTO BETTER AGREEMENT.
UPPER LOW EXPECTED TO MOVE SLOWLY EAST/NORTHEAST AS UPPER RIDGE
BUILDS IN FROM THE WEST. BEST CHANCE OF ACCUMULATING SNOW LOOKS TO
BE SATURDAY NIGHT AS COLDER AIR MOVES IN FROM THE WEST/NORTHWEST ON
THE BACKSIDE OF THE LOW. NORTH WINDS WILL ALSO INCREASE PRODUCING
SOME BLOWING SNOW AND REDUCED VISIBILITIES. ON SUNDAY SNOW WILL
DECREASE FROM WEST TO EAST AND SHOULD BE OUT OF THE AREA SUNDAY
NIGHT. LOWS SATURDAY NIGHT IN THE MID 20S TO LOW 30S...FALLING INTO
THE UPPER TEENS TO LOW 20S SUNDAY NIGHT. HIGHS SUNDAY IN THE 30S.
MONDAY-WEDNESDAY...WARMING TREND COMMENCES WITH SLIGHTLY BELOW
NORMAL TEMPERATURES MONDAY AND ABOVE NORMAL TEMPERATURES TUESDAY AND
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1030 PM MST WED MAR 6 2013
POTENTIAL FOR OVERNIGHT FOG/STRATUS CONTINUES...WITH BEST CHANCES
FOR REDUCTIONS IN FLIGHT CATEGORIES AT MCK. CONFIDENCE SOMEWHAT
LOW ATTM THOUGH AS 00Z RAOBS AND RAP DATA LOWER CONFIDENCE IN HOW
WIDESPREAD FOG POTENTIAL WILL BE. FOR THE TIME BEING...BROUGHT MCK
DOWN TO MIDDLE OF THE ROAD/OPERATIONAL SIGNIFICANT MVFR FOR A
PORTION OF THE OVERNIGHT HOURS. OTHERWISE...VFR CONDITIONS
EXPECTED FOR THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...99
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1226 AM EST THU MAR 7 2013
.SYNOPSIS...
LOW PRESSURE MOVES FURTHER OUT TO SEA THIS MORNING. HIGH PRESSURE
BUILDS INTO THE AREA THIS AFTERNOON INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
INTENSE LOW PRS CONTS TO MOVE FRTR OFFSHORE ATTM. ONLY PCPN LEFT
WAS ALONG THE IMMEDIATE COASTS WITH A MIX OF RAIN/SNOW SHWRS.
LATEST DATA SHOWING M CLR SKIES W OF I95. DESPITE GUSTS OVR 30 MPH
ALONG THE COASTS...WNDS HAVE DMNSHD BELOW WND ADVSRY CRITERIA PAST
FEW HRS SO HAVE DROPPED THE ADVSRY ALL CSTL AREAS XCPT AT ORF/VA
BCH/CURRITUCK NC WHERE GUSTS AOA 40 KTS CONT. LOWS U20S-M30S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
LO PRES CONTS TO MOVE OUT TO SEA THU THROUGH SAT. A SECOND S/W
DIVING SSE FM WRN NEW ENG/NY STATE ON FRI PSBLY RESULTING IN
BKN/OVC CLDNS (ESP E OF I 95) AND ISOLD/SCT PCPN. NNW WINDS WILL
RMN GUSTY AS WELL...ESP NR THE CST...THROUGH FRI. SFC HI PRES IS
SLO TO BUILD SWD INTO THE MDATLC RGN BY SAT...FINALLY RESULTING IN
DRY WX FOR ALL AREAS.
P/MCLDY TNGT...THEN PCLDY OR VRB CLDNS THU. PCLDY W/MCLDY E THU
NGT THROUGH FRI...THEN MSTLY SKC ON SAT. HI TEMPS RANGING THROUGH
THE 40S N AND CNTRL AREAS...TO L50S S THU/FRI...THEN FM THE U40S
TO M50S SAT. LO TEMPS IN THE U20S TO L30S THU/FRI NGTS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GOING WITH A COMBINATION OF THE 12Z GFS/ECMWF FOR THE EXTENDED
PERIOD...ESPLY WITH REGARD TO TIMING OF APPROACH AND PASSAGE OF COLD
FRONT MON NGT THRU TUE. UA RDG/LRG AREA OF SFC HI PRES WILL PROVIDE
DRY WX SAT NGT INTO MON MORNG. LO PRES AND ASSOC COLD FRONT WILL
THEN AFFECT THE REGION MON EVENG THRU TUE...WITH DECENT CHC FOR
SHOWERS. MILDER TEMPS EXPECTED SUN INTO TUE. DRY WX RETURNS FOR TUE
NGT THRU WED...AS HI PRES WILL GRADUALLY BLD IN FM THE NW. MIN TEMPS
WILL BE IN THE LWR TO MID 30S SUN MORNG...IN THE UPR 30S TO LWR 40S
MON MORNG...IN THE 40S TUE MORNG...AND IN THE MID 30S TO ARND 40 WED
MORNG. MAX TEMPS WILL BE IN THE MID 50S TO LWR 60S SUN...IN THE LWR
TO MID 60S MON...IN THE MID 50S TO LWR 60S TUE...AND IN THE MID TO
UPR 50S WED.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE HAS MOVED OFF THE VA/NC COAST AND STRONG WINDS ARE
GUSTING FROM THE N/NNW AT ALL TAF SITES. GUSTS TO 40-45 KT REMAIN
PSBL AT TIMES THROUGH THE OVERNIGHT HOURS...ESPECIALLY ALONG THE COAST.
RAIN AND SNOW WILL TAPER OFF TONIGHT. CIGS AND VSBYS WILL CONTINUE
TO BE IN AND OUT OF IFR CONDS WITH MAINLY IFR ON THE BACKSIDE OF
THE LOW. PCPN ENDS AND DRYING WILL ALLOW CIGS TO IMPROVE AFT 05Z.
VFR CONDS ARE EXPECTED TOWARD MORNING WITH WINDS GUSTING TO 25KT
IN THE AFTN.
THE LOW WILL CONTINUE TO SLOWLY PUSH OFFSHORE ALLOWING HIGH PRESSURE
TO BUILD IN FROM THE NW. FAIR WEATHER/VFR CONDITIONS WILL PREVAIL
INTO EARLY NEXT WEEK WITH GUSTY WINDS CONTINUING DUE TO THE STRONG
PRESSURE GRADIENT THAT WILL REMAIN OVER THE AREA.
&&
.MARINE...
UPDATE: HAVE HOISTED STORM WARNING FOR ATLANTIC COASTAL WATERS
NORTH OF VA/NC BORDER. HAVE BEEN HANDLING WITH SPECIAL MARINE
WARNINGS THUS FAR, BUT WITH HRRR SHOWING THIS SURGE LASTING A FEW
HOURS LONGER, FEEL A BIT MORE COMFORTABLE HOISTING STORM HEADLINE
THROUGH 2AM, WITH A PERIOD OF GALES LIKELY AFTER WINDS DIMINISH
SOME AFTER MIDNIGHT. OTHERWISE, HAVE DROPPED GALES OVER THE RIVERS
TO SCA...IN EFFECT UNTIL MORNING.
PREVIOUS DISCUSSION....
A STRENGTHENING SFC LOW PRESSURE WILL ROTATE OVER THE MID
ATLANTIC COAST THIS EVENING...THEN PUSH OUT TO SEA OVERNIGHT.
WIND DIRECTIONS ARE PRIMARILY N LATE THIS AFTN AND WILL BECOME
MORE NWLY AS THE EVENING PROGRESSES. A NRLY SURGE HAS BEGUN OVER
NRN CHES BAY AND WILL CONTINUE TO PUSH SWD THROUGH THE EVENING.
CURRENT FORECAST ALREADY HAS THIS TREND IN PLACE. FOR COASTAL
WATERS N OF CHINCOTEAGUE...A STORM WARNING HAS BEEN ISSUED THROUGH
EARLY THU MORNING AS THE NRLY SURGE COMMENCES LATE THIS AFTN INTO
THE EVENING AND GUSTS REACH 50-55 KT. IN ADDITION...GALE WARNINGS
HAVE BEEN ISSUED FOR THE RIVERS TO ACCOUNT FOR THE NRLY SURGE AND
FOR WHEN WINDS BECOME NWLY...WHICH IS A FAVORABLE ORIENTATION FOR
STRONG WINDS TO OCCUR. GALES ARE EXPECTED TO FALL BELOW 34 KT AT
VARIOUS TIMES TONIGHT AND THU MORNING...AND WILL BE REPLACED BY
SOLID SCA FLAGS AS DEEMED NECESSARY. SEAS ARE ANYWHERE FROM 10-19
FEET N OF CAPE CHARLES AND 5-9 FT S OF CAPE CHARLES. THEY SHOULD
STAY ELEVATED THROUGH THU MORNING AND THEN FALL VERY SLOWLY
THROUGH THE REST OF THE WEEK.
AS THE SFC LOW PUSHES EAST OF LONGITUDE 70W LATE THU NIGHT INTO
FRI...THE PRESSURE GRADIENT REMAINS TIGHT AND A SECONDARY SHORTWAVE
FEATURE MOVES SE ACROSS THE WATERS. THIS FEATURE WILL BRING A
REINFORCING SHOT OF COLD AIR INTO THE REGION AND THE SUBSEQUENT CAA
WILL PRODUCE ANOTHER ROUND OF SOLID SCA CONDITIONS (POSSIBLY GALES
OVER COASTAL WATERS) THU NIGHT INTO FRI MORNING. WINDS THEN SHIFT TO
THE N FRI NIGHT AND HIGH PRESSURE BEGINS TO BUILD INTO THE AREA FROM
NW...BRINGING MORE QUIET CONDITIONS TO AREA WATERS THROUGH THE
WEEKEND.
&&
.TIDES/COASTAL FLOODING...
UPDATE...COASTAL FLOOD WARNING HAS BEEN UPDATED TO RUN THROUGH
EARLY FRIDAY OVER ALL COASTAL AREAS NORTH OF VA/NC BORDER, WITH
THE EXCEPTION OF LANCASTER/NORTHUMBERLAND COUNTIES, WHERE SLIGHTLY
LOWER WATER LEVELS NECESSITATES ONLY AN ADVISORY. TIDAL DEPARTURES
ON THE ORDER OF 2.5 TO 4 FT ABOVE NORMAL HAVE LED TO MODERATE
COASTAL FLOODING IMPACTS ALREADY OVER MUCH OF THIS AREA, WITH
ADDITIONAL ANOMALIES EXPECTED TONIGHT AND OVERNIGHT. MDL AND CBOFS
GUIDANCE HAVE BOTH UNDERESTIMATED THIS NORTHERLY SURGE THIS
EVENING, AND HAVE SIDED CLOSE TO/JUST ABV VIMS GUIDANCE FOR THIS
PACKAGE, AS IT APPEARS TO BE THE MOST ACCURATE IN DEPICTING TIDAL
LEVELS OCCURRING RIGHT NOW. THIS GUIDANCE INDICATING ANOTHER TIDE
CYCLE BETWEEN 2.5 TO 4 FT ABOVE NORMAL (HIGHEST ALONG MD EASTERN
SHORE). IF THIS GUIDANCE COMES TO FRUITION...MODERATE TO SEVER
COASTAL FLOODING IMPACTS ARE EXPECTED AT OCEAN CITY INLET, WITH
WIDESPREAD MODERATE COASTAL FLOODING EXPECTED ON WESTERN SHORE OF
CHES BAY SOUTH OF NEW PT COMFORT DURING THE THU MORNING HIGH TIDE.
SEE CFWAKQ FOR SITE SPECIFIC DETAILS.
UNFORTUNATELY, THE SLOW MOVEMENT OF THE SFC LOW WILL KEEP POSITIVE
TIDAL ANOMALIES THROUGH FRIDAY. AND WHILE THE TIDE CYCLE THURSDAY
NIGHT APPEARS TO BE CLOSER TO MINOR, THE HIGHER ASTRONOMICAL TIDE
FOR FRIDAY MORNING COULD APPROACH MODERATE CCOASTAL FLOODING
IMPACTS YET AGAIN. SUBSTANTIAL IMPROVEMENT IS EXPECTED LATER
FRIDAY AND ESPECIALLY ON SATURDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR MDZ024-025.
NC...WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ017-102.
VA...COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR VAZ084>086-091-
094>096-098>100.
WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ095-098.
COASTAL FLOOD ADVISORY UNTIL 7 AM EST FRIDAY FOR VAZ077-078.
MARINE...STORM WARNING UNTIL 2 AM EST EARLY THIS MORNING FOR ANZ652-654-
656.
STORM WARNING UNTIL 5 AM EST EARLY THIS MORNING FOR ANZ650.
GALE WARNING UNTIL 7 AM EST FRIDAY FOR ANZ658.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR
ANZ635>637.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR ANZ630>634-638.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...ALB
LONG TERM...BMD
AVIATION...DAP/LSA
MARINE...BMD/MAM
TIDES/COASTAL FLOODING...AKQ
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1126 PM CST WED MAR 6 2013
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 353 PM CST WED MAR 6 2013
BIGGEST CHALLENGE WILL BE DETERMINING SKY COVER AND VISIBILITY FOR
TONIGHT INTO EARLY THURSDAY MORNING.
THE STRATUS THAT STUCK AROUND AND RETROGRADED WESTWARD INTO THE
EASTERN HALF OF THE CWA HAS LONG MIXED OUT...WITH ONLY SOME CIRRUS
MAKING ITS WAY INTO OUR CWA FROM THE SOUTH/SOUTHWEST.
SATELLITE AND WATER VAPOR REVEAL SPLIT FLOW IN UPPER
LEVELS...PLACING OUR CWA BETWEEN. THE SURFACE RIDGE CONTINUES TO
TREK EAST...WHICH WILL EVENTUALLY TURN WIND TO A MORE SE TO S/SE
WIND DIRECTION. MODELS ARE STILL KEYING IN ON SOME POSSIBLE
STRATUS/FOG IN THE WESTERN CWA OVERNIGHT AND INTO THURSDAY
MORNING...AND WITH THIS CONSISTENT SIGNAL...HAVE LEFT IN THE FOG
FROM THE PREVIOUS FORECAST AND EXPANDED THIS A LITTLE FARTHER TO THE
WEST. THE RAP IS PICKING UP SOME INCREASED STRATUS IN THE WEST AND
EVENTUALLY NORTH AS A LOW-LEVEL JET INCREASED DURING THE OVERNIGHT.
THE NMM ALSO INDICATES SOME INCREASE STRATUS OVERNIGHT...BUT OVER A
LARGER PORTION OF THE CWA. CONFIDENCE REMAINS LOW FOR SKY COVER
TONIGHT AS MODELS DO NOT HAVE A GREAT HANDLE ON LOW-LEVEL SKY COVER
AND FRANKLY...HAVE NOT DONE THAT GREAT FOR AWHILE. THE NAM
ADVERTISES SOME LIGHT QPF IN THE NORTHERN CWA...SOMEWHAT NEAR THE
NOSE OF THE MODEST LOW-LEVEL JET DEVELOPING TONIGHT. WITH SUCH A DRY
PROFILE...I DOUBT IF THERE IS MUCH CHANCE AT ALL OF MEASURABLE
PRECIPITATION...ALTHOUGH THIS COULD BE AN INDICATOR OF SOME
DEVELOPING STRATUS...WHICH SEEMS TO BE SUPPORTED BY THE
USING RECENT VERIFICATION STATISTICS...I MADE SOME MINOR CHANGES
TO TEMPERATURES FOR TONIGHT AND THURSDAY...WITH THE REMAINING
SNOWPACK IN THE WESTERN CWA STILL HAVING SOME INFLUENCE WITH HIGH
TEMPERATURES THURSDAY. THIS SNOWPACK MAY HAVE LIMITED EFFECT ON THE
VISIBILITY FOR OVERNIGHT TONIGHT INTO THURSDAY MORNING AS WELL.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 353 PM CST WED MAR 6 2013
MAIN FORECAST CONCERNS ARE PRECIPITATION FRIDAY NIGHT THROUGH SUNDAY
NIGHT AND TEMPERATURES THROUGH THE PERIOD.
AN UPPER LEVEL RIDGE WILL MOVE THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY. THERE IS WARM ADVECTION ACROSS THE AREA AND TEMPERATURES
SHOULD BE WARMER. IN ADDITION...THE SOUTH WINDS INCREASE THE
MOISTURE ACROSS THE AREA AND CLOUDS WILL INCREASE. A COUPLE OF THE
MODELS HAVE STARTED SHOWING SOME LIGHT QPF ASSOCIATED WITH THE WARM
ADVECTION. HAVE KEPT THE FORECAST DRY FOR NOW AND WILL WAIT FOR
FURTHER RUNS.
BY FRIDAY NIGHT AN UPPER LEVEL LOW PRESSURE SYSTEM MOVING OUT OF THE
ROCKIES WILL START TO AFFECT THE AREA. PRECIPITATION SPREADS ACROSS
THE AREA. WARM TEMPERATURES WILL KEEP PRECIPITATION IN THE FORM OF
RAIN. THERE IS SOME WEAK INSTABILITY WITH MUCAPE UP TO 500 J/KG
ACROSS THE AREA. THERE COULD BE SOME ISOLATED THUNDERSTORMS FRIDAY
NIGHT INTO SATURDAY. SATURDAY WILL CONTINUE TO BE WARM AHEAD OF THE
SURFACE LOW WITH SOUTHERLY WINDS.
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE TRACK OF THE
UPPER LOW AS IT MOVES THROUGH THE PLAINS. AS THE UPPER LOW MOVES
THROUGH THE PLAINS THE COLDER AIR MOVES INTO THE AREA FROM THE WEST.
SATURDAY NIGHT THE PRECIPITATION CHANGES FROM RAIN TO SNOW IN THE
WEST DURING THE EVENING THEN THE SNOW SPREADS ACROSS THE AREA DURING
NIGHT. BY MORNING EXPECT SNOW IN THE NORTHWEST WITH RAIN AND SNOW
FURTHER SOUTHEAST. ON SUNDAY SNOW WILL BE FOUND ACROSS MUCH OF THE
AREA WITH SOME RAIN OR SNOW POSSIBLE IN THE SOUTHEAST. THE UPPER LOW
WILL SLIDE TO THE EAST SUNDAY NIGHT AND PRECIPITATION WILL COME TO
AN END. PRECIPITATION AMOUNTS ARE NOT VERY HIGH AND EXPECT SOME SNOW
ACCUMULATIONS. SUNDAY WILL BE COLDER WITH HIGHS ONLY IN THE 30S
BEHIND THE COLD FRONT.
THE UPPER LOW WILL BE TO THE EAST AND THERE WILL BE NORTHWEST FLOW
ACROSS THE AREA MONDAY THROUGH WEDNESDAY. THERE COULD BE SOME CLOUDS
AS A FEW WEAK UPPER LEVEL WAVES MOVE THROUGH THE AREA...BUT THERE IS
WARM ADVECTION AND TEMPERATURES SHOULD START TO WARM UP. DEPENDING
ON HOW MUCH SNOW THERE IS SATURDAY NIGHT INTO SUNDAY THE
TEMPERATURES MAY REMAIN A LITTLE COOLER FOR MONDAY...BUT WARM FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAF THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1126 PM CST WED MAR 6 2013
VFR CONDITIONS ARE CURRENTLY FORECAST FOR THE TAF TONIGHT. MODELS ARE
VERY INCONSISTENT WITH THE POSSIBILITY OF LOW STRATUS CEILINGS AND
LLWS OVERNIGHT. HAVE HIGHER CONFIDENCE WITH LLWS SETTING UP THAN
THE POSSIBILITY OF STRATUS...WILL CONTINUE TO MONITOR FOR STATUS
SETTING UP LATER TONIGHT. VISIBILITIES SHOULD REMAIN VFR
OVERNIGHT AS THE SURFACE WINDS WILL BE AROUND 10KTS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...BEDA/BRYANT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
109 AM EST THU MAR 7 2013
.SYNOPSIS...
A WINTER STORM WILL MOVE OFF THE MID ATLANTIC COAST AND SLOW DOWN
AS IT MOVES UP THE NORTHEASTERN SEABOARD TONIGHT THROUGH THURSDAY
NIGHT. AN UPPER LEVEL LOW WILL TRACK SOUTHEAST FROM THE UPPER
GREAT LAKES TONIGHT THROUGH THURSDAY NIGHT AND SPREAD MORE SNOW TO
MUCH OF CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA THURSDAY
AFTERNOON AND NIGHT. THE SNOW COULD MIX WITH RAIN AT TIMES IN THE
VALLEYS THURSDAY AFTERNOON. ALL THE PRECIPITATION WILL TAPER OFF
FRIDAY. HIGH PRESSURE AND MILDER WEATHER WILL MOVE INTO THE REGION
FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
RECENT RADAR TRENDS SHOWING ANY LINGERING SNOW ACTIVITY QUICKLY
EXITING OFF THE EAST COAST THIS EVENING AS MAIN SFC LOW CONTINUES
TO EXIT TOWARDS THE 40N/70W BENCHMARK. LATEST HRRR AND NEWLY
ARRIVING 00Z NAM BOTH VALIDATE CURRENT RADAR TRENDS AND KEEP ANY
QPF OVERNIGHT EAST OF THE CWA. AS A RESULT...HAVE TRIMMED BACK ON
POPS ACCORDINGLY AND FEEL MUCH IF NOT THE WHOLE NIGHT SHOULD BE
PRECIP FREE. ASIDE FROM THAT...HOURLY TEMPS ADJUSTED AS COLD AIR
ADVECTION ON BACKSIDE OF DEPARTING LOW HAS YET TO ARRIVE. BY EARLY
MORNING...LOWS SHOULD BOTTOM OUT TOWARDS THE UPPER 20S ACROSS MOST
LOCATIONS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
1025 PM UPDATE...
NEWLY ARRIVING 00Z MODEL GUIDANCE FURTHER SUPPORTING CONCERNS FOR
SNOWFALL BEGINNING LATE THURSDAY AFTERNOON AS WRAP AROUND MOISTURE
ON THE BACKSIDE OF AFOREMENTIONED UPPER LOW GETS PULLED WESTWARD
IN ADVANCE OF ANOTHER NORTHERN STREAM TROUGH/CLOSED LOW DIVING
SOUTHEAST FROM THE NORTHERN LAKES. IN FACT...LATEST WATER VAPOR
IMAGERY NOW SHOWING THE APPROACHING WAVE QUITE WELL AND THIS
FEATURE WILL CONTINUE DIVING SOUTHEAST THROUGH CENTRAL PA THU
NGT/EARLY FRI. 24-HR QPF TOTALS FROM THE NAM SUGGEST OVER 1" OF
WATER EQUIVALENT FOR THE EASTERN ZONES...WITH UP TO .7" AS FAR
WEST AS THE I-81 CORRIDOR. FOR WHAT ITS WORTH...18Z GFS ALSO
SHOWING SOME WESTWARD DISPLACEMENT OF MAIN QPF AXIS WHICH LENDS
SUPPORT TO AT LEAST HIGH-END ADVISORY SNOWFALLS FOR THE EASTERN
ZONES. FOR NOW...WILL HOLD OFF ON MAKING ANY WHOLESALE CHANGES AND
ALLOW THE OVERNIGHT SHIFT TO EVALUATE THE FULL MODEL SUITE BEFORE
MAKING ANY HEADLINE ADJUSTMENTS.
PREVIOUS SHORT TERM DISCUSSION...
WATER VAPOR IMAGERY SHOWS A POTENT UPPER LEVEL LOW DIVING
SOUTHEASTWARD FROM THE UPPER GREAT LAKES AT PRESENT. THIS FEATURE
WILL CONT SE REACHING WRN NY THU EVE AND THEN DOWN TO THE DELMARVA
PENINSULA BY 12Z FRI. MEANWHILE THE LARGE CYCLONE THAT WAS MOVG
THRU THE MID- ATLANTIC STATES AT PRESENT WILL MOVE OFFSHORE BUT
SLOW DOWN AND EXPAND ITS LOW TO MID LEVEL EASTERLY FLOW TO
ENCOMPASS ALL OF C NY AND NE PA THU AFTERNOON AND NIGHT. MOISTURE
ADVECTION IN THIS LOW TO MID LEVEL EASTERLY FLOW WILL RISE
ISENTROPICALLY ESP ACRS ERN NY AND NE PA AS THE UPPER LEVEL LOW
MOVING SE ALSO LIFTS THE ISENTROPES. THIS IS AN EXCELLENT
DYNAMICAL SET-UP TO FORCE PRECIPITATION OVER MUCH OF C NY/NE PA
LATE THU AFTERNOON AND NIGHT. SINCE MOST OF THE PRECIPITATION WILL
FALL AT NIGHT AND ALSO FOCUS ON OUR HIGHER TERRAIN AREAS IN
OTSEGO...DELAWARE AND SULLIVAN CO/S IT WILL BE MAINLY SNOW.
HEAVIEST PRECIPITATION WILL BE IN OUR EASTERN ZONES WHERE THE
LIFTG WILL BE THE HIGHEST AND THE MOISTURE WILL BE DEEPER.
HENCE OPTED FOR A WINTER WX ADVY IN DELAWARE...OTSEGO AND SULLIVAN
CO/S THU PM TO FRI AM GIVEN THE CONSENSUS OF THE 12Z GFS...12Z
CMC...12Z HI RES NMM...AND THE 15Z SREF. BLENDED MODEL SNOWFALL
FROM THESE SOURCES AND CAME UP WITH BASICALLY 3-4 INCHES IN THE
DEEPEST VALLEYS OF DELAWARE...SULLIVAN AND OTSEGO CO/S TO 6-8
INCHES OVER THE HIGHEST TERRAIN. MOST OF THESE COUNTIES ARE FAIRLY
ELEVATED SO MOST AREAS LIKELY WILL SEE 4-6 INCHES. REST OF C NY
AND NE PA LIKELY WILL SEE LESS THAN 1 INCH IN VALLEYS TO AS MUCH
AS 3 INCHES HIGHER TERRAIN ALONG THE I-81 CORRIDOR IN NY. WE
DISCOUNTED THE NAM WHICH BURIES THE POCONOS AND CATSKILLS WITH
10-20 INCHES OF SNOW AND GIVES A LARGE PART OF THE REST OF OUR
AREA 5-10 INCHES OF SNOW. BUT THIS TYPE OF SCENARIO DOES BEAR
WATCHING AS THEIR IS STRG MID-LVL FGEN FRCG IN THE PRESENCE OF
WEAK TO NEGATIVE EPV IN THESE AREAS. FOR NOW WAY TOO UNCERTAIN TO
JUMP ON THIS BAND WAGON AND GIVEN THE TRACK RECORD OF THE NAM/S
SNOWFALL RECENTLY WE DID NOT USE FOR NOW.
THE SNOW PEAKS THURSDAY NIGHT AND TAPERS DOWN TO SNOW SHOWERS
FLURRIES AND POTENTIALLY EVEN SOME SPRINKLES/RAIN SHOWERS IN THE
LOWER ELEVATIONS FRIDAY.
FRIDAY NIGHT AND SATURDAY LOOK FAIR WITH MILDER TEMPERATURES ON
SATURDAY AS A RDG OF HIGH PRESSURE BUILDS IN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GIVEN TDA`S FOCUS ON SHORT TERM CONCERNS...WE USED HPC GUIDANCE
FOR THE MED RNG. WE DID MAKE SOME MINOR TWEEKS...PRIMARILY TO CLD
COVER (MORE PESSIMISTIC) AND TO A LESSER XTNT WINDS AND TEMPS AS A
BACK DOOR CDFNT TRIES TO DROP SWD ON SUN NGT. THIS FEATURE COULD
HAVE A SIG EFFECT ON TEMPS ACRS NRN ZONES ON MON...IN ADVANCE OF
THE OCCLUDED FNT FCST TO PASS LATE ON MON NGT. AFTER SOME MILD
TEMPS THIS WEEKEND...READINGS WILL COOL BY MID WEEK TO MORE
SEASONABLE VALUES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A THICK VFR STRATUS DECK WILL HANG OVER THE TERMINALS INTO THE
AFTERNOON HOURS ON THURSDAY. TEMPO MVFR CEILINGS ARE POSSIBLE AT
KBGM MAINLY DUE TO ELEVATION EFFECTS.
A STORM SYSTEM OFF THE ATLANTIC COAST WILL WRAP MOISTURE BACK
ACROSS NY AND PA THURSDAY NIGHT. SNOW MAY REACH INTO THE I-81
CORRIDOR, BRINGING LOW MVFR AND TEMPO IFR RESTRICTIONS TO MOST OF
THE TERMINALS. TIMING SUGGESTS THE SNOW WILL BEGIN BETWEEN 23Z AND
02Z, AND CONTINUE THROUGH LATE MORNING FRIDAY. THE BEST CHANCE FOR
LONG TERM RESTRICTIONS WILL BE AT AVP AND BGM.
.OUTLOOK...
FRI/SAT/SUN...MVFR IN -SN INTO MIDDAY FRI. VFR OTHERWISE.
MON...MVFR IN -SHRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 11 AM EST
FRIDAY FOR NYZ046-057-062.
&&
$$
SYNOPSIS...DJN
NEAR TERM...CMG/DJN
SHORT TERM...DJN
LONG TERM...
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS PORTLAND OR
850 PM PST WED MAR 6 2013
.SYNOPSIS...LOW PRESSURE ESSENTIALLY STALLED OVER THE PACIFIC
NORTHWEST WILL LINGER AND WEAKEN THROUGH THURSDAY. THIS WILL KEEP THE
WEATHER UNSETTLED WITH LIGHT TO MODERATE RAIN AT TIMES THROUGH
THURSDAY. SNOW LEVELS WILL HOVER AROUND 2500 FT THROUGH THURSDAY
NIGHT...THOUGH HEAVIER SHOWERS MAY TEMPORARILY LOWER THE SNOW LEVEL
AT TIMES. THIS SYSTEM WILL SLOWLY MOVE EAST INTO THE ROCKIES...
ALLOWING AN UPPER RIDGE TO BUILD IN FOR WARMER AND DRIER WEATHER
FRIDAY AND POSSIBLY THROUGH THE WEEKEND.
&&
.SHORT TERM...A BROAD UPPER LEVEL TROUGH JUST OFF THE OREGON COAST
CONTINUES TO PRODUCE AN UNSETTLED AND MESSY PATTERN ACROSS THE
PACIFIC NORTHWEST. THE MAIN UPPER LEVEL LOW SPINNING OFF THE SOUTH
OREGON COAST WILL CONTINUE TO DROP SOUTHWARD PLACING MUCH OF WESTERN
OREGON UNDER DEEP SOUTHWESTERLY FLOW. A DEFORMATION AXIS
EXTENDING NORTHEASTWARD FROM THIS LOW PRESSURE TO THE MOUTH OF THE
COLUMBIA RIVER AND PORTIONS OF SOUTHWEST WASHINGTON IS CURRENTLY
PRODUCING STEADIER PRECIPITATION ACROSS PACIFIC COUNTY AND PRIMARILY
POINTS NOW NORTH OF OUR CWA. THE GFS AND EC GENERALLY AGREE THIS
DEFORMATION AXIS SHOULD GRADUALLY WEAKEN NEAR ITS CURRENT LOCATION
OVER THE NEXT 12 HOURS. MEANWHILE...THE NAM ACTUALLY MOVES THIS
BOUNDARY BACK TOWARDS THE SOUTHEAST OVERNIGHT TOWARDS
PORTLAND...ALBEIT THE LATEST MODEL RUN HAS TRENDED TOWARDS THE GLOBAL
MODELS. AS A RESULT...POPS WERE HEDGED HIGHEST TOWARDS ASTORIA AND
THE WILLAPA HILLS OVERNIGHT INTO THURSDAY MORNING AS THIS FEATURE
DECAYS IN PLACE.
MEANWHILE...A RELATIVELY MOIST AND UNSTABLE AIRMASS IS PRODUCING
ISOLATED TO SCATTERED SHOWERS OVER THE WILLAMETTE VALLEY THIS
EVENING. OROGRAPHIC ASCENT INTO THE SOUTH WASHINGTON CASCADES HAS
BEEN QUITE PRONOUNCED IN THE SOUTHWESTERLY FLOW AS SHOWERS CONTINUE
TO DEVELOP RAPIDLY IN THE FOOTHILLS NORTHEAST OF VANCOUVER. MANY
SITES ACROSS THE SOUTH WASHINGTON CASCADES HAVE ALREADY REACHED
WINTER WX ADVISORY CRITERIA AND THE MODELS GENERALLY AGREE DECENT
OROGRAPHICS WILL CONTINUE THROUGH ABOUT 12Z TONIGHT. AS A
RESULT...WE WENT AHEAD AND ISSUED A WINTER WX ADVISORY. UPON FURTHER
INSPECTION...RADAR RETURNS HAVE LET UP AT LEAST A BIT IN THE LAST
HOUR. THIS IS LIKELY IN RESPONSE TO THE BEST OMEGA BECOMING
INCREASINGLY CONFINED TO BELOW THE DENDRITIC LAYER AS SEEN IN THE
LATEST NAM AND RUC CROSS SECTIONS. AS A RESULT...CONFIDENCE IS LOW
THAT ANOTHER 6 INCHES WILL FALL TONIGHT...BUT WILL KEEP THE ADVISORY
GOING FOR NOW.
ALSO WENT AHEAD AND REMOVED THE MENTION OF THUNDER FROM THE CENTRAL
OREGON COAST AS CONVECTION HAS REMAINED TOO SHALLOW TO PRODUCE ENOUGH
CHARGE SEPARATION TO GENERATE LIGHTNING. /NEUMAN
PREVIOUS DISCUSSION BELOW...BELIEVE MODELS ARE A LITTLE OVERDONE ON
CLOUD COVER THURSDAY...BUT NONETHELESS IT SHOULD BE A MOSTLY CLOUDY
DAY WITH PLENTY OF STRATOCUMULUS. THERE PROBABLY WILL BE ENOUGH SUN
BREAKS TO GENERATE ENOUGH SHALLOW INSTABILITY FOR MORE SHOWERS
THURSDAY...ESPECIALLY OVER THE HIGHER TERRAIN. WITH FREEZING LEVELS
LOW...THE MORE VIGOROUS SHOWERS COULD PRODUCE SMALL HAIL. HOWEVER
THESE SHOWERS SHOULD BE CAPPED AROUND 10-12 KFT...WHICH SHOULD LIMIT
THE THREAT FOR THUNDER.
CLEARING TREND BEGINS IN EARNEST THU NIGHT...WITH A CHILLY NIGHT
EXPECTED FOR THE VALLEYS. AFTER STARTING OFF WITH SOME PATCHES OF
FOG...FRIDAY WILL BE PARTLY TO MOSTLY SUNNY ASIDE FROM SOME MOUNTAIN
CLOUDS AND ISOLATED SHOWERS. UPPER LEVEL RIDGING BUILDS FRI NIGHT AND
SATURDAY...WITH MORE NIGHT/MORNING FOG POSSIBLE. SINCE THIS RIDGE IS
RATHER FLAT...THERE COULD BE SOME HIGH CLOUDS ESPECIALLY IN THE
NORTHERN ZONES...OTHERWISE MILD AND SUNNY CONDITIONS EXPECTED FOR
SATURDAY. WEAGLE
.LONG TERM...SATURDAY EVENING THROUGH TUESDAY...A BREAK IN THE
WEATHER IS EXPECTED FOR THE WEEKEND AS A FLAT UPPER LEVEL RIDGE
BUILDS OVER THE AREA. MODELS AGREE ON KEEPING ANY SYSTEMS TO THE
NORTH THROUGH SUNDAY...THOUGH WITH THE FLAT RIDGE OVER THE AREA AND
WESTERLY FLOW ALOFT BRINGING MOISTURE INTO WASHINGTON...THE
PRECIPITATION IS NEVER VERY DISTANT FROM OUR AREA. CURRENTLY MODELS
AGREE ON LIMITING PRECIPITATION GENERALLY TO WASHINGTON. SOUTHWEST
WASHINGTON ISNT LIKELY TO SEE MUCH PRECIPITATION UNLESS THE JET
STREAM SLIPS SOUTHWARD A BIT. MODEL CONSENSUS IS TO DROP THE RIDGE
SOUTH BY LATE TUESDAY AND BRING A CHANCE OF RAIN TO THE AREA. A
STRONGER TROUGH FOLLOWS SOMETIME NEAR THE END OF THE WEEK. KWELSON
&&
.AVIATION...THE STEADY RAIN HAS MOVED NORTH INTO WESTERN WASHINGTON
WITH SCATTERED SHOWERS NOW STREAMING INTO NW OREGON. COASTAL
AREAS LIKELY TO REMAIN IN MVFR CIGS TONIGHT AND THU MORNING BUT
MODEL TRENDS INDICATE LOW VFR IS LIKELY THU AFTERNOON. INLAND
AREAS SHOULD REMAIN VFR THROUGH 10Z THU THEN MVFR WITH CIGS
AROUND 2000 TO 2500 FT BECOMING MORE COMMON. BUT THAT SHOULD LAST
THROUGH ABOUT 17Z TO 20Z THU. THE COAST RANGE AND CASCADES WILL BE
FREQUENTLY OBSCURED THROUGH AROUND 06Z THU...WITH THE S WA
CASCADES AND FAR N OREGON CASCADES OBSCURED THROUGH AT LEAST 18Z
THU.
KPDX AND APPROACHES...PREDOMINANT VFR EXPECTED THROUGH ABOUT 10Z.
MOIST BOUNDARY LAYER AND INCREASING STABILITY OVERNIGHT SHOULD
LEAD TO MVFR CIGS AROUND 10Z AND CONTINUING UNTIL 18Z THU OR
SO. VFR EXPECTED AFTER THAT AND LIKELY CONTINUING THROUGH 06Z FRI.
&&
.MARINE...SURFACE TROUGH LAY NORTH TO SOUTH ACROSS THE WATERS
TONIGHT. A SMALL SURFACE LOW OFF THE SOUTH COAST IS BRINGING
ADVISORY WINDS TO THE CENTRAL COASTAL WATERS. MODELS ARE IN SOME
DISAGREEMENT WITH THE EVOLUTION OF THE TROUGH AND LOW OVERNIGHT
INTO THU MORNING. FOR NOW WILL KEEP THE ADVISORY FOR WINDS THROUGH
7 AM THU...BUT IT COULD LAST A LITTLE LONGER.
SEAS WILL HOVER IN THE 5 TO 7 FOOT RANGE THROUGH FRI NIGHT.
HOWEVER SEAS WILL BE CLOSE TO 10 FT OVER THE CENTRAL WATERS MAINLY
DUE TO SHORTER PERIOD WIND WAVES. LATEST MODEL GUIDANCE SHOWS A
SET OF LONGER-PERIOD SEAS REACHING THE WATERS SATURDAY...BUT NOT
QUITE UP TO 10 FT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...WINTER WEATHER ADVISORY UNTIL 4 AM PST THURSDAY FOR SOUTH
WASHINGTON CASCADES.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 AM PST THURSDAY FOR
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
346 AM CST THU MAR 7 2013
.SHORT TERM...TODAY THROUGH SATURDAY
346 AM CST THU MAR 7 2013
MAIN FORECAST CONCERNS ARE ON THE STORM SYSTEM EXPECTED TO IMPACT
THE AREA FRIDAY NIGHT THROUGH SUNDAY.
LATEST WATER VAPOR IMAGERY SHOWED A WEAK UPPER LOW OVER NORTHERN
LAKE SUPERIOR MOVING SOUTHEAST. A BROAD UPPER TROUGH WAS MOVING INTO
THE WEST COAST AS RIDGING WAS OCCURRING OVER THE CENTRAL CONUS.
SURFACE OBSERVATIONS INDICATED HIGH PRESSURE OVER THE FORECAST
AREA...WITH THE RIDGE AXIS EXTENDING FROM WESTERN ONTARIO SOUTH
THROUGH THE MID MISSISSIPPI RIVER VALLEY.
AFTER SOME PATCHY DENSE FOG THIS MORNING...HIGH PRESSURE WILL BE IN
CONTROL ACROSS THE AREA TODAY PROVIDING QUIET WEATHER. PASSING HIGH
CLOUDS...CIRRUS...ARE EXPECTED TO MOVE OVER THE AREA TODAY AS THEY
SPILL OVER THE RIDGE AHEAD OF THE TROUGH DIVING INTO THE WESTERN
U.S. PLAN ON MOSTLY SUNNY SKIES TODAY WITH HIGHS RANGING FROM THE
LOWER TO MID 30S. THE HIGH WILL START TO SLIDE EAST TONIGHT.
MEANWHILE THE WESTERN TROUGH IS EXPECTED TO DIG SOUTH THROUGH
SOUTHERN CALIFORNIA. SURFACE LOW PRESSURE WILL DEVELOP IN THE LEE
OF THE ROCKIES PRODUCING SOUTHERLY FLOW ACROSS THE PLAINS INTO THE
UPPER MISSISSIPPI RIVER VALLEY. SLIGHTLY WARMER AIR WILL ADVECT
NORTHWARD STARTING TONIGHT AND CONTINUING INTO FRIDAY. 925 MB
TEMPERATURES START OUT AROUND -7C ACROSS MOST OF THE AREA
TODAY...WARMING TO AROUND 1C OVER SOUTHEAST MINNESOTA AND TO
AROUND -5 C OVER CENTRAL WISCONSIN OVERNIGHT. PLAN ON PARTLY
CLOUDY SKIES TONIGHT WITH LOWS RANGING FORM THE LOWER 20S WEST OF
THE MISSISSIPPI RIVER TO THE TEENS FOR LOCATIONS TO THE EAST.
A WEAK SHORTWAVE LOOKS TO MOVE ACROSS NORTH DAKOTA AND INTO WESTERN
ONTARIO ON FRIDAY...PASSING WELL TO THE NORTH OF THE FORECAST AREA.
CLOUDS WILL BE ON THE INCREASE ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY ON ON FRIDAY AS THE WESTERN TROUGH MOVES THROUGH THE FOUR
CORNERS REGION AND LOW PRESSURE DEEPENS OVER EASTERN COLORADO. FLOW
ALOFT WILL TURN SOUTHWEST LATE IN THE DAY ON FRIDAY OVER THE
FORECAST AREA. MEANWHILE...A NORTHERN STREAM TROUGH IS EXPECTED TO
RACE ACROSS SOUTHERN ALBERTA/SASKATCHEWAN AND MERGE WITH THE ENERGY
LIFTING OUT OF THE SOUTHWEST. AN INVERTED SURFACE TROUGH DEVELOPS
ACROSS THE UPPER MIDWEST FRIDAY NIGHT EXTENDING FROM SOUTHWEST
NEBRASKA NORTHEAST INTO NORTHWEST WISCONSIN. GULF MOISTURE SURGES
NORTHWARD FRIDAY NIGHT INTO SATURDAY WITH DEWPOINTS CLIMBING INTO
THE UPPER 40S TO LOWER 50S OVER THE CENTRAL PLAINS. A MOISTURE RICH
AIRMASS STREAMS INTO THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY
MORNING WITH PRECIPITABLE WATER VALUES CLIMBING TO 8/10 OF AN INCH
BY EARLY SATURDAY MORNING...THEN INCREASING THROUGH THE DAY TO
AROUND 9/10 OF AN INCH BY SATURDAY EVENING...WHICH IS AROUND 270
PERCENT OF NORMAL. EXPECT A MIXTURE OF FREEZING RAIN AND SLEET
FRIDAY NIGHT AS THIS AIRMASS MOVES. THE MIX SHOULD SWITCH OVER TO
ALL RAIN BY MID SATURDAY MORNING. ICE ACCUMULATIONS OF 1/10 OF AN
INCH ARE POSSIBLE FROM LATE FRIDAY NIGHT INTO EARLY SATURDAY
MORNING. IN ADDITION...PATCHY FOG LOOKS TO DEVELOP WEST OF THE
MISSISSIPPI RIVER FRIDAY NIGHT AN COULD BE LOCALLY DENSE AT TIMES.
THE RAIN WILL CONTINUE THROUGH THE DAY ON SATURDAY. TEMPERATURES ARE
EXPECTED TO WARM GRADUALLY WARM FROM LATE FRIDAY NIGHT INTO SATURDAY
MORNING. HIGHS ON SATURDAY WILL RANGE FROM THE MID TO UPPER 30S OVER
NORTH CENTRAL WISCONSIN TO THE LOWER 40S ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN. RAINFALL AMOUNTS ON
SATURDAY INTO SATURDAY NIGHT WILL RANGE FROM 1/2 INCH OVER NORTH
CENTRAL WISCONSIN TO AROUND 8/10 OF AN INCH OVER PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN. CANNOT RULE OUT SOME 1
INCH REPORTS FOR A FEW AREAS SOUTH OF INTERSTATE 90 BY EARLY SUNDAY
MORNING. SOME MELTING SNOW AND THE EXPECTED RAINFALL COULD LEAD TO
RUNOFF INTO AREA RIVERS AND STREAMS RESULTING IN SOME RISES AND
POSSIBLY ICE JAMS...SEE HYDROLOGY SECTION BELOW. THE SURFACE TROUGH
SLIDES OVER THE FORECAST AREA SATURDAY NIGHT WITH WINDS BECOMING
LIGHT. THESE LIGHT WINDS COUPLED WITH A MOIST AIRMASS OVER THE AREA
AND MELTING SNOW WILL LEAD TO DENSE FOG CONCERNS. AREAS OF DENSE FOG
COULD DEVELOP SATURDAY EVENING AND CONTINUE THROUGH THE OVERNIGHT
HOURS.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
346 AM CST THU MAR 7 2013
07.00 MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SUNDAY INTO
MONDAY SHOWING THE UPPER TROUGH PROGRESSING EAST THROUGH THE FORECAST
AREA ON SUNDAY AND INTO THE EASTER GREAT LAKES REGION SUNDAY NIGHT.
RAIN SHOULD GRADUALLY SWITCH OVER TO SNOW FROM THE NORTHWEST TO
SOUTHEAST ON SUNDAY AS THE TROUGH MOVES IN. THE PRECIPITATION WILL
END BY SUNDAY EVENING AS HIGH PRESSURE BUILDS IN FROM THE NORTHERN
PLAINS. TEMPERATURES WILL RETURN TO MORE SEASONABLE VALUES ON MONDAY
WITH HIGHS IN THE UPPER 20S TO LOWER 30S. A FAST MOVING SHORTWAVE IS
EXPECTED TO MOVE ACROSS NORTHERN MINNESOTA INTO NORTHERN WISCONSIN
MONDAY NIGHT THROUGH TUESDAY BRINGING SNOW CHANCES TO FAR NORTH
CENTRAL WISCONSIN. HIGH PRESSURE RETURNS BY MIDWEEK WITH QUIET
WEATHER EXPECTED. HIGH TEMPERATURES TUESDAY THROUGH THURSDAY WILL
RANGE FROM THE MID TO UPPER 30S.
&&
.AVIATION...THROUGH 06Z FRIDAY
1120 PM CST WED MAR 6 2013
AS THE HIGH PRESSURE RIDGE CONTINUES TO BUILD INTO THE AREA THIS
EVENING...THE CLOUDS OVER MINNESOTA HAVE CONTINUED TO RETREAT TO
THE WEST. THESE ARE NOW MAINLY WEST OF A KMKT TO KAXA LINE AND THE
07.03Z RAP SUGGESTS THESE CLOUDS WILL NOW REMAIN WEST OF THE AREA.
SOME PATCHY DENSE FOG HAS FORMED BUT IS VARIABLE ON HOW MUCH OF
VISIBILITY RESTRICTION OCCURS. BOTH KTOB AND KAUM WERE DOWN TO
1/4SM AT 07.04Z BUT KAUM IMPROVED TO 1SM AT 07.05Z. KRST BOUNCED
FROM 6SM DOWN TO 1SM BACK UP TO 4SM BETWEEN 07.04Z AND 07.05Z.
WITH THE LIGHT WINDS AND CLEAR SKIES OVERHEAD...WOULD EXPECT THE
FOG TO CONTINUE FORMING AND HAVE TAKEN KRST DOWN TO IFR CONDITIONS
FOR THE OVERNIGHT HOURS. THE RAP IS NOT AS AGGRESSIVE WITH THE FOG
AT KLSE WITH THE BUFKIT SOUNDING SUGGESTING SATURATION AT THE
SURFACE WILL NOT OCCUR. CONFIDENCE IS NOT HIGH ON WHAT THE
VISIBILITY WILL DO AT KLSE BUT FOR NOW HAVE STAYED WITH MVFR
CONDITIONS. EXPECTING THE FOG TO DISSIPATE BY MID MORNING THURSDAY
AS THE MIXING INCREASES ON THE BACK SIDE OF THE SURFACE HIGH WITH
SOUTHEAST WINDS. ONCE THE FOG IS GONE...VFR CONDITIONS EXPECTED
FOR THE REMAINDER OF THE PERIOD.
&&
.HYDROLOGY...
346 AM CST THU MAR 7 2013
THE EXPECTED RAINFALL AND SNOWMELT FROM FRIDAY NIGHT THROUGH
SATURDAY COULD RESULT IN RUNOFF INTO AREA RIVERS AND
STREAMS...LEADING TO RISES AND POTENTIAL ICE JAMS. THE CURRENT
SNOWPACK IN PLACE ACROSS THE AREA WILL ABSORB SOME OF THE
RAINFALL. HOWEVER...THE BOTTOM LAYER OF THE SNOW PACK IS FAIRLY
HARD/CRUSTED. MOST OF THE ABSORPTION SHOULD OCCUR IN THE TOP MOST
RECENTLY FALLEN SNOW LAYER. THE TOP LAYER OF SOIL IS FROZEN SOLID
WITH CONCRETE FROST SO WHAT THE SNOW DOES NOT ABSORB WILL GO
DIRECTLY INTO RUNOFF. AT THIS TIME RAINFALL AMOUNTS OF 1/2 INCH TO
AROUND 1 INCH ARE POSSIBLE. THE HIGHER AMOUNTS WOULD MOST LIKELY
FALL ACROSS FAR NORTHEAST IOWA INTO SOUTHWEST WISCONSIN. WILL
MAINTAIN A VERY CLOSE WATCH ON THIS SITUATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
335 AM CST THU MAR 7 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1120 PM CST WED MAR 6 2013
.SHORT TERM...TONIGHT THROUGH SATURDAY
248 PM CST WED MAR 6 2013
FORECAST CONCERNS THROUGH THE SHORT TERM PERIOD INCLUDE FOG
POTENTIAL TONIGHT AND THEN LIKELIHOOD OF PRECIPITATION FRIDAY NIGHT
THROUGH SATURDAY.
HAVE BEEN WATCHING SATELLITE CLOSELY TODAY REGARDING CLEARING TREND
OF STRATOCUMULUS OR LACK THEREOF IN SOME CASES AS A RIDGE OF HIGH
PRESSURE BUILDS EAST ACROSS MN/IA. FAIRLY LARGE HOLE IN THE CLOUDS
NOW EXTENDING SOUTH WARD FROM WESTERN LAKE SUPERIOR THROUGH
SOUTHEAST MN/WESTERN WI. THIS WAS DO TO SOME MIXING ALBEIT VERY
LIGHT UNDER SUBSIDENT REGIME. FARTHER WEST UNDER THE RIDGE AXIS
ITSELF ACROSS SOUTHWEST MN/CENTRAL IA...STRATOCUMULUS WAS THICKER
WITH LACK OF MIXING. THIS COULD LEND TO A TRICKY
CLOUD/FOG/TEMPERATURES FORECAST TONIGHT.
MODEL-WISE...LOOKS LIKE REALLY NO MAJOR DIFFERENCES WERE NOTED WITH
THE 12Z RUN.
FOR TONIGHT...AS MENTIONED ABOVE...COULD BE A TRICKY FORECAST
DEPENDING ON WHAT CLOUDS DO. WHERE THE CLOUDS STICK AROUND OUT
WEST...TEMPERATURES SHOULD TREND WARMER. HOWEVER...WHERE CLEARING
OCCURS ALONG AND EAST OF THE MISSISSIPPI RIVER...TEMPERATURES COULD
REALLY TANK. THINKING FAVORED LOW-LYING BOG COUNTRY AND RELATIVELY
FRESH SNOW PACK WILL LIKELY DRIVE LOWS TONIGHT INTO THE SINGLE
DIGITS BELOW ZERO. MEANWHILE...WHERE CLOUDS LINGER...WILL LIKELY SEE
LOWS IN THE TEENS. WILL ALSO HAVE TO WATCH FOG POTENTIAL TONIGHT
GIVEN LOWER BOUNDARY LAYER MOISTURE LOADING FROM TODAY/S PARTIAL
SNOWMELT WITH DEW POINTS IN THE UPPER TEENS AS OF 2 PM. HAVE
MAINTAINED AREAS OF FOG FOR TONIGHT/EARLY THURSDAY MORNING...BUT NOT
CONFIDENT HOW THICK IT WILL BECOME DUE TO THE CLOUD ISSUE UNDER THE
RIDGE AXIS.
PLAN ON WARMING FOR THURSDAY INTO FRIDAY AS SURFACE HIGH PRESSURE
EXITS EAST OF THE AREA AND FLOW TURNS MORE SOUTHERLY. NAM HAS
925-850MB TEMPERATURES IN THE -5C TO 0C RANGE ON THURSDAY...AND -1C
TO +3C ON FRIDAY. THIS SHOULD EQUATE TO HIGHS IN THE UPPER 20S TO
LOWER 30S THURSDAY AND NEAR NORMAL LEVELS IN THE MIDDLE 30S TO
AROUND 40 ON FRIDAY.
FOR FRIDAY NIGHT INTO SATURDAY...A STRONG MID-LEVEL TROUGH COMBINED
WITH CYCLOGENESIS ON THE LEESIDE OF THE COLORADO ROCKIES/HIGH PLAINS
WILL TAP GULF MOISTURE NORTHWARD TOWARD THE AREA. NAM/GFS SHOWING
NOSE OF INCREASING 925-850MB MOISTURE TRANSPORT GETTING INTO THE
AREA BY FRIDAY EVENING WITH PRECIPITABLE WATER VALUES REACHING AROUND
0.75 INCH OR 200-250 PERCENT ABOVE NORMAL BY SATURDAY 12Z. NAM
SOUNDINGS SHOW INITIALLY DRY LOWER LEVELS WITH COLUMN SATURATION
OCCURRING AT OR ABOVE 700MB BEFORE MIDNIGHT...THEN TOTAL COLUMN
SATURATION BY 12Z SATURDAY MORNING. AS SUCH...HELD PRECIPITATION TO
CHANCE CATEGORY BEFORE MIDNIGHT FRIDAY...AND THEN LIKELY CATEGORY
//WEST OF THE MISSISSIPPI RIVER//AFTER MIDNIGHT. NOW...AS FAR AS
P-TYPE...THERMAL PROFILES SUPPORT A WINTRY MIX THROUGH FRIDAY NIGHT
WITH FREEZING RAIN AND SLEET THE LIKELY OUTCOME.
THROUGH THE DAY SATURDAY...WILL LIKELY SEE A TRANSITION FROM A
WINTRY MIX TO ALL RAIN AS WARMING CONTINUES AHEAD OF THE MID-LEVEL
TROUGH AND SURFACE LOW MOVING OUT OF THE PLAINS. GULF MOISTURE TAP
CONTINUES INTO THE AREA WITH PRECIPITABLE WATER VALUES INCREASING
INTO THE 0.75-1.00 INCH RANGE. MELTING SNOW AND RAINFALL INCREASES
HYDROLOGY CONCERNS. HAVE INCLUDED A SEPARATE DISCUSSION SECTION
BELOW TO SORT OUT THE DETAILS.
MAY HAVE TO CONSIDER EVENTUAL HEADLINES FRIDAY NIGHT INTO SATURDAY
MORNING FOR WINTRY MIX SCENARIO.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
248 PM CST WED MAR 6 2013
06.12Z MEDIUM RANGE MODELS IN GOOD AGREEMENT. EXPECT A TRANSITION
FROM RAIN TO SNOW AND PERHAPS SOME SLEET SATURDAY NIGHT AS A COLD
FRONT DROPS THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION. THEN
FOR SUNDAY THROUGH MONDAY...A WAVE OF LOW PRESSURE RIPPLES
NORTHEAST ALONG THIS FRONTAL BOUNDARY WITH DEFORMATION RAIN/SNOW
EXTENDING NORTHWESTWARD INTO THE FORECAST AREA. WEATHER LOOKS
FAIRLY QUIET MONDAY NIGHT THROUGH WEDNESDAY WITH WEST/NORTHWEST
FLOW ACROSS THE AREA. WILL KEEP A EYE ON A WEAK MID-LEVEL TROUGH
DROPPING INTO THE AREA MONDAY NIGHT/TUESDAY TIME FRAME FOR A
CHANCE OF LIGHT SNOW MAINLY NORTH OF I-94. OTHERWISE...WITH
WEST/NORTHWEST FLOW ALOFT...LOOK FOR NORMAL TO SLIGHTLY BELOW
NORMAL TEMPERATURES THROUGH THE PERIOD WITH HIGHS MAINLY IN THE
MIDDLE/UPPER 30S.
&&
.AVIATION...THROUGH 06Z FRIDAY
1120 PM CST WED MAR 6 2013
AS THE HIGH PRESSURE RIDGE CONTINUES TO BUILD INTO THE AREA THIS
EVENING...THE CLOUDS OVER MINNESOTA HAVE CONTINUED TO RETREAT TO
THE WEST. THESE ARE NOW MAINLY WEST OF A KMKT TO KAXA LINE AND THE
07.03Z RAP SUGGESTS THESE CLOUDS WILL NOW REMAIN WEST OF THE AREA.
SOME PATCHY DENSE FOG HAS FORMED BUT IS VARIABLE ON HOW MUCH OF
VISIBILITY RESTRICTION OCCURS. BOTH KTOB AND KAUM WERE DOWN TO
1/4SM AT 07.04Z BUT KAUM IMPROVED TO 1SM AT 07.05Z. KRST BOUNCED
FROM 6SM DOWN TO 1SM BACK UP TO 4SM BETWEEN 07.04Z AND 07.05Z.
WITH THE LIGHT WINDS AND CLEAR SKIES OVERHEAD...WOULD EXPECT THE
FOG TO CONTINUE FORMING AND HAVE TAKEN KRST DOWN TO IFR CONDITIONS
FOR THE OVERNIGHT HOURS. THE RAP IS NOT AS AGGRESSIVE WITH THE FOG
AT KLSE WITH THE BUFKIT SOUNDING SUGGESTING SATURATION AT THE
SURFACE WILL NOT OCCUR. CONFIDENCE IS NOT HIGH ON WHAT THE
VISIBILITY WILL DO AT KLSE BUT FOR NOW HAVE STAYED WITH MVFR
CONDITIONS. EXPECTING THE FOG TO DISSIPATE BY MID MORNING THURSDAY
AS THE MIXING INCREASES ON THE BACK SIDE OF THE SURFACE HIGH WITH
SOUTHEAST WINDS. ONCE THE FOG IS GONE...VFR CONDITIONS EXPECTED
FOR THE REMAINDER OF THE PERIOD.
&&
.HYDROLOGY...
248 PM CST WED MAR 6 2013
CONCERN INCREASING SLIGHTLY WITH ANTICIPATED RAINFALL/SNOWMELT
FRIDAY NIGHT THROUGH SATURDAY NIGHT. MODELS INDICATING A GOOD SLUG
OF GULF MOISTURE ADVECTING NORTHWARD INTO THE UPPER MISSISSIPPI
RIVER REGION. RIGHT NOW...EXPECTING RAINFALL//CENTERED ON SATURDAY//
OF A 1/4 TO 1/2 INCH. THINKING THAT CURRENT SNOWPACK IN PLACE WOULD
BE ABLE TO ABSORB MOST OF THIS RAINFALL AS SNOWPACK TEMPERATURES
STILL IN THE TEENS ACROSS NORTH CENTRAL WISCONSIN...AND IN THE
MIDDLE 20S ACROSS SOUTHERN WI/NORTHEAST IA. HOWEVER...IF WE DO END
UP WITH MORE RAINFALL GIVEN FAIRLY HIGH PRECIPITABLE WATER VALUES IN
THE COLUMN OF ATMOSPHERE...OR WARMER TEMPERATURES AND FURTHER
RIPENING OF THE SNOWPACK...RUNOFF COULD BECOME A PROBLEM. FROST
DEPTH IS QUITE DEEP /1.5 TO 3 FEET/ AND THE TOP SEVERAL INCHES ARE
FROZEN SOLID WITH CONCRETE FROST. ANY SNOWMELT OR RAINFALL WILL ALL
RUN OFF INTO WATERWAYS. THERE IS ALSO ICE IN SOME OF OUR CREEKS AND
RIVERS...SO IF THERE IS A RISE...WE COULD ALSO SEE SOME ICE ACTION.
AS SUCH...WE WILL CONTINUE TO KEEP A CLOSE EYE ON THIS
SITUATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
248 PM CST WED MAR 6 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
351 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST FOCUS IS ON
SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE MENDOCINO. COMPARED
TO 24 HOURS AGO THE MODELS ARE NOW BRINGING THE MAIN CORE OF THE
LOW CLOSER TO THE BAY AREA LATER THIS AFTERNOON AND
EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK OF THE ENERGY
AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS SOUTHERN
CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT WAS
ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH THE
MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE NUMEROUS
ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO INCREASE
THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW APPROACHES
THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR PRECIP IN THE
NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE BULK OF THE
SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD. HIGHER CONFIDENCE
THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE FOCUSED OVER THE
SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF THE LOW WILL THEN
DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS WILL BE LIGHT WITH
0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW STAYS OFF SHORE
THE COLDEST AIR ALOFT WONT INFILTRATE THE REGION...THUS SNOW
LEVELS SHOULD GENERALLY STAY 3000 FEET AND HIGHER. HAVE FINE TUNED
THE INHERITED WINTER WX ADVISORY FOR THE HIGHER TERRAIN OF
MONTEREY AND SAN BENITO COUNTY TO DELAY THE START AND SHORTEN THE
END TIME TO THE PRE-DAWN HOURS OF TOMORROW. THE MAIN PRECIP WILL
WIND DOWN BY 12Z FRIDAY WITH JUST SOME SCATTERED SHOWERS LEFT OVER
ON FRIDAY MORNING FOR THE MONTEREY BAY REGION...DECREASING TO
ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 3:50 AM PST THURSDAY...A STORM SYSTEM IS
FORECAST TO MOVE TOWARD THE REGION LATER THIS MORNING. THIS STORM
WILL BRING RAIN SHOWERS TO THE TERMINALS...MAINLY IMPACTING KSJC
SOUTHWARD. MAINLY LIGHT AND VARIABLE WINDS ALONG WITH VFR CIGS
WILL ACCOMPANY THIS STORM. SHOWER ACTIVITY WILL SUBSIDE THIS
EVENING INTO THE OVERNIGHT HOURS.
VICINITY OF KSFO...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST. RAIN SHOWERS ARE FORECAST TO IMPACT THE BAY BY
17Z...WITH A STRAY SHOWER POSSIBLE BEFORE THIS TIME. LIGHT
SOUTHERLY WINDS WILL BECOME WESTERLY BY THIS AFTERNOON. RAIN
SHOWER ACTIVITY WILL MOVE OUT OF THE REGION BY 10Z FRIDAY.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH
THE FORECAST. RAIN SHOWER ACTIVITY WILL INCREASE EARLY THIS
AFTERNOON AND CONTINUE THROUGH THE OVERNIGHT HOURS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY AND
AND SAN BENITO COUNTY FROM 1 PM THURSDAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: RWW
AVIATION/MARINE: RILEY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
337 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST FOCUS IS ON
SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE MENDOCINO. COMPARED
TO 24 HOURS AGO THE MODELS ARE NOW BRINGING THE MAIN CORE OF THE
LOW CLOSER TO THE BAY AREA LATER THIS AFTERNOON AND
EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK OF THE ENERGY
AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS SOUTHERN
CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT WAS
ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH THE
MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE NUMEROUS
ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO INCREASE
THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW APPROACHES
THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR PRECIP IN THE
NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE BULK OF THE
SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD. HIGHER CONFIDENCE
THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE FOCUSED OVER THE
SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF THE LOW WILL THEN
DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS WILL BE LIGHT WITH
0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW STAYS OFF SHORE
THE COLDEST AIR ALOFT WONT INFILTRATE THE REGION...THUS SNOW
LEVELS SHOULD GENERALLY STAY 3000 FEET AND HIGHER. HAVE FINE TUNED
THE INHERITED WINTER WX ADVISORY FOR THE HIGHER TERRAIN OF
MONTEREY AND SAN BENITO COUNTY TO DELAY THE START AND SHORTEN THE
END TIME TO THE PRE-DAWN HOURS OF TOMORROW. THE MAIN PRECIP WILL
WIND DOWN BY 12Z FRIDAY WITH JUST SOME SCATTERED SHOWERS LEFT OVER
ON FRIDAY MORNING FOR THE MONTEREY BAY REGION...DECREASING TO
ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 9:30 PM PST WEDNESDAY...SOME HIGH CLOUDS WERE
STILL STREAMING OVER THE AREA ASSOCIATED WITH A JET STREAK EXITING
TO THE EAST. INCREASING STABILITY TONIGHT MAY LEAD TO A FEW FOG
PATCHES INLAND VALLEYS VERY LATE TONIGHT WHERE MOSTLY CLEAR SKIES
PREVAIL. BEST CHANCES FOR RADIATIONAL COOLING WILL BE OVER THE
NORTHERN HALF OF THE AREA WHERE SUBSIDENCE PREVAILS TONIGHT.
A MUCH COLDER UPPER LOW WILL MOVE SOUTH OVER THE COASTAL WATERS
THURSDAY BRINGING SHOWERS BACK INTO THE PICTURE THURSDAY AND
THURSDAY NIGHT. A SLIGHT INCREASE IN INSTABILITY PARAMETERS SUGGESTS
POSSIBLE ISOLATED THUNDER AFTER 21Z PER CHECK ON MODIFIED FORECAST
SOUNDINGS. INSTABILITY GRADUALLY DECLINES THURSDAY NIGHT AS THE
CORE OF THE COLDEST AIR SHIFTS WEST AND THEN SOUTH OF THE AREA
REACHING SOCAL FRIDAY MORNING.
VICINITY OF KSFO...VFR. LIGHT WINDS. DRY RUNWAYS ARE EXPECTED TIL
INSTABILITY/POSSIBLE SHOWER ACTIVITY ARRIVES THURSDAY AFTERNOON
AND EVENING.
KSFO BRIDGE APPROACH...VFR. AREA WEATHER PATTERN IS NOT VERY
FAVORABLE FOR FOG PATCHES. IF ANY DO DEVELOP THURSDAY MORNING
THEY SHOULD QUICKLY MIX OUT AFTER SUNRISE.
MONTEREY BAY AREA TERMINALS...HIGH CLOUDS CONTINUE TO STREAM IN
FROM THE WSW. VFR. BEST CHANCES FOR WET WEATHER ARRIVES BY LATE
THURSDAY MORNING OR EARLY AFTERNOON.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY AND
AND SAN BENITO COUNTY FROM 1 PM THURSDAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: RWW
AVIATION/MARINE: CANEPA
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
951 AM CST THU MAR 7 2013
.DISCUSSION...
ISSUED 951 AM CST THU MAR 7 2013
CLOUDS CONTINUE TO PLAGUE CENTRAL AND SOUTHEAST ILLINOIS THIS
MORNING...THANKS TO MOISTURE TRAPPED BENEATH A STRONG LOW-LEVEL
SUBSIDENCE INVERSION. LATEST VISIBLE SATELLITE IMAGERY SHOWS A
RATHER THIN OVERCAST ACROSS THE REGION...WITH MAJOR RIVERS DIMLY
VISIBLE THROUGH THE CLOUD COVER. GIVEN RELATIVE THINNESS OF CLOUDS
AND STRENGTH OF EARLY MARCH SUN...THINK A FEW HOLES WILL BE
PUNCHED IN THE OVERCAST AS THE DAY GOES ON. HOWEVER...WITH STRONG
INVERSION IN PLACE AND LITTLE OR NO WIND...EXPECT GENERALLY CLOUDY
CONDITIONS THROUGH THE DAY. WINDS WILL BECOME LIGHT AND EASTERLY
LATER TODAY/TONIGHT...AS SURFACE HIGH SHIFTS INTO THE OHIO RIVER
VALLEY. THIS MAY TEND TO ADVECT LOW-LEVEL MOISTURE BACK INTO THE
AREA TONIGHT. WHILE 12Z NAM FORECAST SOUNDINGS INDICATE CLEARING
BY EVENING...14Z RUC SOUNDINGS MAY HAVE A BETTER HANDLE ON
REALITY...INDICATING MOSTLY CLOUDY CONDITIONS PERSISTING THROUGH
THE NIGHT.
BARNES
&&
.AVIATION...
ISSUED 556 AM CST THU MAR 7 2013
A PESKY AREA OF MVFR STRATUS/STRATO CUMULUS CONTINUES TO PLAGUE
THE CENTRAL ILLINOIS TERMINALS. IN FACT...THE AREAL COVERAGE OF
THE CLOUDS HAS EXPANDED SOME OVERNIGHT. EXPECT THE EDGES OF THE
CLOUDS TO ERODE TODAY...WITH SKIES POSSIBLY SCATTERING OUT BY THIS
EVENING. HOWEVER...THERE IS THE POTENTIAL THE THE CLOUDS WILL HANG
ON EVEN LONGER AS THERE IS A STRONG LOW LEVEL INVERSION TO TRAP
MOISTURE...AND LOW LEVEL WINDS ARE TOO WEAK TO EFFECTIVELY SCOUR
THE CLOUDS OUT. IN FACT...THE LOW LEVEL FLOW TURNS EASTERLY
TONIGHT AND MAY ACT TO BLOW CLOUDS BACK WEST INTO THE AREA AFTER
CLEARING HAS TAKEN PLACE OVERHEAD.
BAK
&&
.PREV DISCUSSION...
ISSUED 307 AM CST THU MAR 7 2013
EARLY MORNING SURFACE MAP SHOWED HIGH PRESSURE RIDGING RUNNING THE
LENGTH OF THE MISSISSIPPI RIVER. RATHER TIGHT INVERSION JUST ABOVE
900 MB HAS PUT THE KIBOSH ON ANY REAL EROSION OF THE LARGE
STRATOCUMULUS DECK OVER MUCH OF THE MIDWEST...WITH ONLY AREAS
AROUND JACKSONVILLE SEEING ANY SUSTAINED CLEARING AND THAT HAS
BEGUN TO FILL IN AS WELL. THE CLOUDS HAVE KEPT TEMPERATURES IN THE
20S...WHICH IS GOOD SINCE CLEAR SKIES OVER THE SUBSTANTIAL SNOW
COVER IN THE NORTHERN CWA WOULD HAVE LIKELY RESULTED IN SINGLE
DIGITS AND TEENS IN THAT AREA. LOOKING UPSTAIRS...LATEST WATER
VAPOR IMAGERY SHOWING SEVERAL CIRCULATIONS IN A BROAD AREA OF 500
MB LOW PRESSURE OVER THE PACIFIC NORTHWEST. DEVELOPMENT OF THIS
PARTICULAR FEATURE WILL BE OF INTEREST TO OUR FORECAST FOR THE
WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY...
FAIRLY QUIET WEATHER EXPECTED IN THE SHORT TERM...AS THE HIGH
PUSHES EAST ACROSS THE GREAT LAKES. FORECAST SOUNDINGS SHOW THE
INVERSION SLOW TO ERODE THOUGH...SO WILL KEEP THE EASTERN CWA
FAIRLY CLOUDY TODAY AND TRY TO MARK SOME CLEARING ACROSS THE WEST
BY MIDDAY. MAIN CONCERN WILL BE WITH FOG POTENTIAL TONIGHT ACROSS
THE NORTH...WITH WINDS STILL FAIRLY LIGHT AND SOME POTENTIAL FOR
SNOW MELT TODAY. SHOULD SKIES STAY CLOUDY...THIS WOULD BE LESS OF
A CONCERN.
TEMPERATURE-WISE...WILL CONTINUE THE TREND OF KEEPING HIGHS A FEW
DEGREES COOLER ACROSS THE NORTH WHERE THE SNOW DEPTH RANGES FROM 5
TO 9 INCHES. HOWEVER...EVEN THESE AREAS MAY CRACK 40 BY FRIDAY...
WITH HIGHS 45-50 FURTHER SOUTH.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
UPPER LOW IN THE PACIFIC NORTHWEST SHOULD BETTER ORGANIZE AS IT
DROPS SOUTHWARD ALONG THE CALIFORNIA COAST TONIGHT AND FRIDAY.
LATEST MODEL GUIDANCE CONTINUES TO EJECT THIS FEATURE NORTHEAST
THIS WEEKEND...AS A DEEPENING SHORTWAVE TRACKS EAST ACROSS THE
CANADIAN PRAIRIES. SOME PHASING OF THE TWO FEATURES IS INDICATED
LATER THIS WEEKEND OVER THE CENTRAL U.S. AND THIS WILL
SIGNIFICANTLY INCREASE PRECIP CHANCES AS THE WEEKEND PROGRESSES.
GOOD MOISTURE SURGE SHOULD TAKE PLACE AHEAD OF THIS PHASING...
WITH GFS PRECIPITABLE WATER VALUES OF 1.25 INCHES SATURDAY NIGHT
NEAR THE 99TH PERCENTILE FOR EARLY MARCH. WOULD NOT BE SURPRISED
TO SEE OVER AN INCH OF RAIN IN SOME AREAS SATURDAY NIGHT THROUGH
SUNDAY NIGHT. HAVE INTRODUCED CATEGORICAL RAIN CHANCES SATURDAY
NIGHT NORTHWEST OF THE ILLINOIS RIVER...AND ALSO ADDED AREAS OF
FOG ACROSS THE NORTHERN CWA DUE TO THE HEAVIER RAIN AND RAPID SNOW
MELT. SUNDAY WILL START OUT RATHER WET AS WELL. HOWEVER...THE
MODELS BEGIN TO DIVERGE IN TERMS OF WHETHER A DRY SLOT MAY SPREAD
IN DURING THE DAY. WITH THE DIVERSITY...WILL NOT TRY TO GET TOO
CUTE WITH SPLITTING OUT MORNING AND AFTERNOON PERIODS.
TEMPERATURES BOTH DAYS SHOULD REACH WELL INTO THE 50S.
SUNDAY NIGHT AND MONDAY...THE GFS AND ECMWF MODELS BOTH SHOW THE
NORTHERN WAVE EXITING THE AREA...WHILE ANOTHER LOW DEVELOPS OVER
THE SOUTHERN PLAINS. THE GFS IS MORE AGGRESSIVE WITH CLOSING THIS
LOW OFF AND LIFTING IT NORTHEAST...WHILE THE ECMWF WEAKENS BACK
INTO AN OPEN WAVE. LEANING MORE TOWARD THE ECMWF SOLUTION FOR
NOW...AND HAVE LIMITED LIKELY POPS SUNDAY NIGHT TO THE SOUTHEAST
THIRD OF THE CWA. HAVE KEPT SOME PRECIP CHANCES IN ON MONDAY FOR
NOW...BUT CONFIDENCE IS LOW AT THE MOMENT. HAVE LARGELY KEPT THE
PRECIP AS RAIN EXCEPT FOR A MIX IN THE NORTHWEST.
MODEL AGREEMENT DOES NOT IMPROVE AS THE WEEK PROGRESSES...WITH THE
LONGER RANGE SOLUTIONS VARYING WITH THE STRENGTH OF ANOTHER WAVE
DROPPING INTO THE GREAT LAKES ON TUESDAY. THE ECMWF SOLUTION WOULD
BE MUCH COOLER FOR US WITH SIGNIFICANT RIDGING WEST OF THE
ROCKIES. FOR NOW HAVE KEPT TEMPERATURES ABOUT 5 DEGREES BELOW
NORMAL FOR THE END OF THE FORECAST PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
815 AM CST THU MAR 7 2013
.DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* POTENTIAL FOR FOG FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 12Z...
VFR STRATUS DECK REMAINS IN PLACE OVER THE CHICAGO AREA WITH HIGH
END MVFR CIGS WEST OF THE CHICAGO AREA INCLUDING RFD. GUIDANCE IS
NOT HANDLING THE SITUATION WELL NOR HOW LONG TO HANG ONTO THE CIGS
THROUGH THE DAY. HAVE TRENDED SLOWER WITH CLEARING AS COLD BOUNDARY
LAYER UNDERNEATH A MODERATE INVERSION MAY KEEP MOISTURE LOCKED IN
THROUGH THE DAY. THERE IS SUBTLE COOLING NOTED AT 925MB THIS
AFTERNOON WHICH MODEL SOUNDINGS SUGGEST MAY LEAD TO LOWERING MVFR
CIGS AROUND 020...HOWEVER THINK THE MODELS ARE LIKELY OVERDOING THE
DIURNAL HEATING COMPONENT TODAY AND RESULTANT LAPSE RATES...AND
DO NOT HAVE CONFIDENCE IN THIS SCENARIO PANNING OUT. WILL STICK WITH
SCT020 IN THE MEANTIME. WINDS ARE EXPECTED TO REMAIN LESS THAN 10 KT
THROUGH THE DAY...AND SHOULD GRADUALLY VEER FROM NW THIS MORNING TO
EASTERLY OVERNIGHT.
IN THE EVENT WE DO CLEAR OUT TODAY...WILL THEN HAVE TO KEEP AN EYE
ON THE FOG POTENTIAL. CONCEPTUALLY...LIGHT WINDS CLOSE TO THE RIDGE
AXIS...PERHAPS SOME ADDITIONAL BL MOISTURE WITH TEMPS PEAKING ABOVE
FREEZING THIS AFTERNOON HELPING TO MELT SOME OF THE SNOW...AND CLEAR
SKIES/FRESH SNOW SHOULD ALL LEAD TO STRONG RADIATIONAL COOLING AND
ENHANCED FOG POTENTIAL. DENSE FOG WAS OBSERVED OVERNIGHT TO OUR
WEST. BUT FOR NOW...BANKING ON CLOUDY SKIES STICKING AROUND TODAY
MINIMIZING THE FOG THREAT.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOWPACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* LOW CONFIDENCE ON TIMING CLEARING OF VFR CIGS...AND RESULTING
FOG POTENTIAL OVERNIGHT.
* MMEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
529 AM CST THU MAR 7 2013
.DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* POTENTIAL FOR MVFR CIGS THURSDAY AFTERNOON.
* POTENTIAL FOR FOG FRIDAY MORNING.
BMD
//DISCUSSION...UPDATED 12Z...
VFR STRATUS DECK REMAINS IN PLACE OVER THE CHICAGO AREA WITH HIGH
END MVFR CIGS WEST OF THE CHICAGO AREA INCLUDING RFD. GUIDANCE IS
NOT HANDLING THE SITUATION WELL NOR HOW LONG TO HANG ONTO THE CIGS
THROUGH THE DAY. HAVE TRENDED SLOWER WITH CLEARING AS COLD BOUNDARY
LAYER UNDERNEATH A MODERATE INVERSION MAY KEEP MOISTURE LOCKED IN
THROUGH THE DAY. THERE IS SUBTLE COOLING NOTED AT 925MB THIS
AFTERNOON WHICH MODEL SOUNDINGS SUGGEST MAY LEAD TO LOWERING MVFR
CIGS AROUND 020...HOWEVER THINK THE MODELS ARE LIKELY OVERDOING THE
DIURNAL HEATING COMPONENT TODAY AND RESULTANT LAPSE RATES...AND
DO NOT HAVE CONFIDENCE IN THIS SCENARIO PANNING OUT. WILL STICK WITH
SCT020 IN THE MEANTIME. WINDS ARE EXPECTED TO REMAIN LESS THAN 10 KT
THROUGH THE DAY...AND SHOULD GRADUALLY VEER FROM NW THIS MORNING TO
EASTERLY OVERNIGHT.
IN THE EVENT WE DO CLEAR OUT TODAY...WILL THEN HAVE TO KEEP AN EYE
ON THE FOG POTENTIAL. CONCEPTUALLY...LIGHT WINDS CLOSE TO THE RIDGE
AXIS...PERHAPS SOME ADDITIONAL BL MOISTURE WITH TEMPS PEAKING ABOVE
FREEZING THIS AFTERNOON HELPING TO MELT SOME OF THE SNOW...AND CLEAR
SKIES/FRESH SNOW SHOULD ALL LEAD TO STRONG RADIATIONAL COOLING AND
ENHANCED FOG POTENTIAL. DENSE FOG WAS OBSERVED OVERNIGHT TO OUR
WEST. BUT FOR NOW...BANKING ON CLOUDY SKIES STICKING AROUND TODAY
MINIMIZING THE FOG THREAT.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOWPACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* LOW CONFIDENCE IN MVFR CIGS THURSDAY AFTERNOON.
* LOW CONFIDENCE ON TIMING CLEARING OF VFR CIGS...AND RESULTING
FOG POTENTIAL OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1048 AM EST THU MAR 7 2013
.SYNOPSIS...
ISSUED AT 328 AM EST THU MAR 7 2013
LAKE SHORE AREAS WILL SEE OCCASIONAL FLURRIES OR LIGHT SNOW
TODAY...OTHERWISE IT WILL BE PARTLY TO MOSTLY CLOUDY WITH
TEMPERATURES IN THE 30S. DRY WEATHER IS EXPECTED FOR FRIDAY AND
MUCH OF SATURDAY. TEMPERATURES WILL WARM TO AROUND 40 ON FRIDAY AND
INTO THE 40S FOR SATURDAY.
A RATHER UNSETTLED PERIOD IS EXPECTED LATE IN THE WEEKEND AND INTO
EARLY NEXT WEEK. RAIN IS EXPECTED BY LATE SATURDAY OR SATURDAY
NIGHT AND CONTINUING INTO SUNDAY. THE PRECIPITATION MAY CHANGE TO
SNOW...OR A MIX OF RAIN AND SNOW SUNDAY NIGHT THROUGH MONDAY
NIGHT...AS TEMPERATURES COOL FOR NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1046 AM EST THU MAR 7 2013
I DECREASED CLOUD COVER FOR THE REMAINDER OF THE DAY. MANY OF THE
CLOUDS THAT WERE AROUND THIS MORNING HAVE CONTINUED TO ERODE AND
EXIT TO EAST. CLEARING WILL CONTINUE FROM WEST TO EAST THIS
AFTERNOON AND THIS IS SHOWN BY THE NAM AND RAP MODEL SUGGESTIONS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
A SMALL AREA OF LAKE EFFECT SNOW SHOWERS/FLURRIES WAS CLIPPING
WESTERN VAN BUREN COUNTY THIS MORNING. EXPECT THIS MAY LINGER MUCH
OF TODAY AS COLD ADVECTION PEAKS AROUND MID DAY. THE FLOW REMAINS
330-350 SO ONLY THE LAKE SHORE WILL EXPERIENCE OCCASIONAL FLURRIES
OR LIGHT SNOW. IT COULD RESULT IN A LIGHT DUSTING IN SOME LOCALES.
INLAND AREAS SHOULD SEE A MIX OF CLOUDS AND SUN...WITH THE CLOUDS
MORE FREQUENT THAN SUN. SLIGHTLY COOLER THAN YESTERDAY WITH MOSTLY
LOW AND MID 30S FOR HIGHS.
UPPER RIDGING MOVES FOR THE END OF THE WORK WEEK. ALONG WITH THIS
WILL COME WARM ADVECTION. ANY LAKE SNOW SHOULD END BY THIS EVENING
ON THE HEELS OF THE WARM ADVECTION. SKIES SHOULD GRADUALLY CLEAR
LEADING TO A MOSTLY SUNNY FRIDAY WITH TEMPS APPROACHING 40.
CLOUDS SHOULD THICKEN THROUGH SATURDAY WITH WARM ADVECTION CLOUDS
AND AN INCREASING GULF MOISTURE FLOW. THE WARM FETCH WILL PUSH
TEMPS WELL INTO THE 40S. WE MAY SEE A FEW RAIN SHOWERS TOWARD
SATURDAY EVENING AS THE LOW LEVELS MOISTEN AHEAD OF A SYSTEM
DEVELOPING OVER THE CENTRAL PLAINS.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
SCATTERED TO NUMEROUS RAIN SHOWERS ARE EXPECTED SATURDAY NIGHT AND
SUNDAY AS A WARM AIR ADVECTION PATTERN IMPACTS THE REGION. 40 TO 50
KT SOUTHERLY LOW LEVEL JET IS PROGGED OUT AHEAD OF AN APPROACHING
FRONTAL BOUNDARY... WITH NARROW CORRIDOR OF PWATS AROUND ONE INCH
STREAMING NORTH. WILL NOT INCLUDE THUNDER AT THIS POINT... BUT WILL
HAVE TO WATCH FOR THAT POSSIBILITY. MODELS ARE STILL STRUGGLING WITH
TIMING/STRENGTH OF JET STREAK ENERGY EJECTING NORTHEAST FROM THE
FOUR CORNERS REGION... BUT IT DOES LIKE A STRONG SHORTWAVE WILL BE
MOVING INTO IOWA AROUND 12Z SUNDAY.
CURRENT MODEL SOLUTIONS IMPLY THAT THE SHORTWAVE MOVING NEWD FROM
THE CENTRAL PLAINS REGION ON SUNDAY WILL WEAKEN AND SHEAR OUT AS IT
COMES INTO MI AND GETS ABSORBED IN WITH AN APPROACHING NRN STREAM
TROUGH. THE SFC FRONTAL BOUNDARY ALSO WEAKENS BUT DOES SLIP THROUGH
THE ENTIRE CWFA BY 12Z MONDAY. MODELS HAVE BEEN VERY INCONSISTENT IN
REGARDS TO WHAT HAPPENS AFTER THAT... BUT CONTINUE TO SUGGEST THE
POSSIBILITY OF ANOTHER WAVE MOVING MOVING NORTHEAST ALONG THE SFC
FRONT EARLY NEXT WEEK. PRECIP TYPE REMAINS PROBLEMATIC... SINCE
IF THE FRONT GETS HUNG UP THEN THE LOW LEVEL COLD AIR MAY HAVE A
TOUGH TIME FILTERING INTO THE REGION FROM THE NORTH.
DESPITE THE MODEL INCONSISTENCIES FOR EARLY NEXT WEEK... ALL
SOLUTIONS SEEM TO EVENTUALLY CONVERGE ON A RATHER CHILLY PATTERN BY
MID WEEK WITH TROUGHING AND COLD AIR ALOFT. THIS WOULD LEAD TO
SCATTERED SNOW OR MIXED RAIN AND SNOW SHOWERS AND HIGHS IN THE 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 655 AM EST THU MAR 7 2013
MVFR CIGS WERE IMPACTING MUCH OF THE AREA THIS MORNING... BUT
CONDITIONS SHOULD TREND TOWARD MOSTLY VFR BY NOON AS HIGH
PRESSURE OVER WISCONSIN MOVES EAST.
THERE HAS BEEN AREAS OF IFR/LIFR FOG ASSOCIATED WITH THE SFC HIGH
PRESSURE RIDGE CURRENTLY TO OUR WEST. THAT MAY BE A CONCERN ACROSS
MICHIGAN LATE TONIGHT SINCE THE RIDGE WILL BE OVERHEAD. HOWEVER AT
THIS POINT OPTED TO LEAVE IT OUT OF THE TAFS AS CONFIDENCE IN FOG
DEVELOPMENT IS LOW AND IT IS DEPENDENT ON CLEARING OF THE CURRENT
CLOUD COVER.
&&
.MARINE...
ISSUED AT 328 AM EST THU MAR 7 2013
RATHER LIGHT NW WINDS TODAY WILL KEEP WAVES ON THE LOWER SIDE.
WINDS REMAIN LIGHT THROUGH MUCH OF THE SHORT TERM. HOWEVER WINDS
AND WAVES SHOULD INCREASE BY SATURDAY AFTERNOON AS THE NEXT SYSTEM
APPROACHES.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST THU MAR 7 2013
A GRADUAL THAW WILL CONTINUE WITH ABOVE FREEZING DAYTIME TEMPS AND
DROPPING BELOW FREEZING AT NIGHT. WARMER CONDITIONS ARRIVE OVER THE
WEEKEND ALONG WITH SOME RAIN. THIS COMBINATION WILL BE MONITORED
FOR POSSIBLE HYDRO IMPACTS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...JAM WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1022 AM EST THU MAR 7 2013
.SYNOPSIS...
STRONG LOW PRESSURE OFF THE MIDATLANTIC COAST WILL MOVE FURTHER OUT
TO SEA TODAY. DRY HIGH PRESSURE WILL BUILD INTO THE REGION THIS
AFTERNOON... AND LINGER THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1022 AM THURSDAY...
REST OF TODAY: A MUCH QUIETER DAY THAN THE LAST FEW... ALTHOUGH
WE`LL STILL SEE SOME CLOUDINESS (ESPECIALLY FAR WEST AND IN THE
NORTHEAST) ALONG WITH BELOW-NORMAL TEMPS AND GUSTY WINDS. THE
POWERFUL STORM SYSTEM IS CENTERED WELL OFF THE MIDATLANTIC COAST
ACCORDING TO THE LATEST SURFACE ANALYSIS... ALTHOUGH ITS CIRCULATION
WILL CONTINUE TO PULL LOW LEVEL MOISTURE (BENEATH THE SUBSIDENCE
INVERSION ALOFT) INTO NORTH CENTRAL AND NORTHEAST NC. 925-850 MB
PROGS FROM THE 12KM NAM AS WELL AS THE HRRR INDICATE STRATOCU
SPREADING TO THE SSE INTO THIS AREA TODAY... AND MORNING SOUNDINGS
AND TRAJECTORIES ALONG WITH SATELLITE IMAGERY SUPPORT A PERIOD OF
PARTLY SUNNY TO MOSTLY CLOUDY SKIES OVER THE COASTAL PLAIN AND
NORTHEAST PIEDMONT THROUGH THE REST OF THE DAY. OVER THE FAR WESTERN
PIEDMONT... OROGRAPHICALLY ENHANCED CIRRUS IS LIKELY TO PERSIST FOR
A FEW MORE HOURS GIVEN THAT OBSERVED AND FORECAST SOUNDINGS SHOW A
FAVORABLE WIND PROFILE. THE THICKER CLOUDS IN THE NORTHEAST WILL
IMPACT TEMPS... AS SUGGESTED BY THE LATEST HRRR OUTPUT... SUGGESTING
HIGHS THERE IN THE LOWER 50S... WHEREAS AREAS FROM THE TRIANGLE AND
TRIAD TO THE SOUTH AND SW SHOULD SEE HIGHS IN THE MID-UPPER 50S. THE
MIXED LAYER NOTED IN FORECAST SOUNDINGS SUPPORTS GUSTS AROUND 20-25
MPH IN THE FAR NORTHEAST (NEAREST THE TIGHTER MSLP GRADIENT) BUT
JUST 15-20 ELSEWHERE... BEFORE THE DEPARTURE OF THE STORM SYSTEM
RESULTS IN A SLOW DIMINISHING OF WINDS TOWARD NIGHTFALL. -GIH
TONIGHT...STRONG VORT MAX IN THE NW FLOW ALOFT WILL DROP SEWD FROM
THE NORTHERN GREAT LAKES INTO NORTHERN MID ATLANTIC TONIGHT THEN OFF
THE VIRGINIA CAPE BY EARLY FRI. THIS SYSTEM WILL BE MOISTURE STARVED
SO EXPECT LITTLE IN THE MANNER OF CLOUDS. HOWEVER...THIS SYSTEM WILL
MAINTAIN A FAIRLY TIGHT PRESSURE GRADIENT SO WINDS WILL MAINTAIN
5-9KTS OVERNIGHT. THIS MIXING WILL AID TO KEEP TEMPS UP A BIT. IF
SFC WINDS DECOUPLE...MORE LIKELY IN THE WESTERN PIEDMONT...COULD SEE
TEMPS TUMBLE 4-5 DEGREES COLDER THAN FORECAST. MIN TEMPS UPPER 20S
WEST TO LOWER 30S COASTAL PLAIN. -WSS
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 300 AM THURSDAY...
FRIDAY AND FRIDAY NIGHT...AS STRONG VORT EXITS OFF THE MID ATLANTIC
COAST...LOW LEVEL FLOW WILL BECOME MORE N-NE. SOME MODELS
(ESPECIALLY NAM) DEPICT MORE OF A FETCH OFF THE ATLANTIC WHILE THE
GFS AND ECMWF MAINTAIN A NLY FLOW (MAINLY OVER LAND). CONSIDERING
THE AMOUNT OF MOISTURE ON THE BACK SIDE OF THE DEEP LOW...NAM MAY BE
ONTO SOMETHING. THUS HAVE INCREASED CLOUD COVERAGE IN THE EAST LATE
FRI INTO FRIDAY NIGHT. WITH A FEW MORE CLOUDS EXPECTED NE VERSUS
SW...SHOULD SEE COOLER MAX TEMPS NE AND WARMER SW. MAX TEMPS NEAR 50
NORTHERN COASTAL PLAIN TO MID-UPPER 50S SW. MIN TEMPS FRIDAY NIGHT
HIGHLY DEPENDENT ON EXTENT OF CLOUD COVERAGE. USED A BLEND OF MOS
GUIDANCE FOR MIN TEMPS. HOWEVER IF CLOUDS DO MATERIALIZE...MIN TEMPS
WILL NEED TO BE ADJUSTED UP A FEW DEGREES. CONVERSELY...IF CLOUDS DO
NOT FORM AND SFC WINDS DECOUPLE...MIN TEMPS WILL NEED TO BE ADJUSTED
DOWN 4-5 DEGREES.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 250 AM THURSDAY...
THIS WEEKEND: BENEATH A BUILDING AND SLOWLY PROGRESSIVE RIDGE
ALOFT...1030 MB SURFACE HIGH PRESSURE WILL SPAN THE LENGTH OF THE
EAST COAST. THE RIDGING WILL PROVIDE FOR GENERALLY CLEAR AND
MODERATING CONDITIONS FOR CENTRAL NC...WITH THE ONLY APPRECIABLE
CLOUD COVER...ASIDE FROM CIRRUS...LIKELY TO HOLD WEST OF THE YADKIN
IN RETURN LOW LEVEL FLOW SUN NIGHT-MON MORNING. STEADILY RISING
THICKNESSES SUGGEST HIGHS AROUND 60 DEGREES SAT...AND IN THE
LOWER-MIDDLE 60S SUN. BELOW GUIDANCE LOWS IN THE 29 TO 34 DEGREE
RANGE WITH EXCELLENT RADIATIONAL SAT NIGHT...AND ABOUT 10 DEGREES
MILDER SUN NIGHT.
MONDAY THROUGH WEDNESDAY: THE DEEP LAYER RIDGING WILL CONTINUE
EASTWARD IN THE AFOREMENTIONED SLOWLY PROGRESSIVE FLOW...IN ADVANCE
OF A COMPLEX TROUGH ALOFT OVER AND OFFSHORE THE PAC NW COAST THIS
MORNING. MEDIUM RANGE GUIDANCE IS IN REASONABLY GOOD AGREEMENT
REGARDING THE PROGRESSION OF THIS TROUGH AND ACCOMPANYING WET LOW
LEVEL FRONTAL ZONE ACROSS CENTRAL NC MON NIGHT-TUE...WITH A
PRECEDING RESIDUAL CAPPING INVERSION LIKELY TO HOLD THROUGH THE DAY
MON. INHERENT UNCERTAINTY AT THIS TIME RANGE FAVORS HOLDING POP IN
THE 50-60 PERCENT RANGE...BUT CATEGORICAL PROBABILITIES WILL
ULTIMATELY BE WARRANTED WITH TIME GIVEN THE EXPECTED WIDE-OPEN AND
STRONG GULF INFLOW INTO THE FRONTAL ZONE. POST-FRONTAL COOLER AND
DRIER CONDITIONS WILL PREVAIL FOR MID-LATE WEEK.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 625 AM THURSDAY...
VFR CONDITIONS ARE EXPECTED ACROSS CENTRAL NC TODAY THROUGH
FRIDAY. A DEEP LOW PRESSURE SYSTEM OFFSHORE WILL CONTINUE TO
INFLUENCE OUR SENSIBLE WEATHER. PRONOUNCED CYCLONIC FLOW WILL RESULT
IN BREEZY CONDITIONS TODAY WITH FREQUENT GUSTS 20-25KTS...ESPECIALLY
OVER THE COASTAL PLAIN (KRWI). NLY FLOW IN THE 925-850MB LAYER HAS
ADVECTED MOISTURE INTO THE WESTERN PIEDMONT...RESULTING IN A DECK OF
STRATUS BETWEEN 3500-4500FT. AS LOW LEVEL FLOW BACKS AND BECOMES
NW...CLOUD COVERAGE WILL DIMINISH. OTHERWISE A DECK OF STRATOCU WILL
DEVELOP LATER THIS MORNING WITH BASES BETWEEN 4000-5000FT. THIS
CLOUD DECK SHOULD BE RELATIVELY THIN AND SHOULD DISSIPATE WITHIN A
FEW HOURS AFTER SUNSET.
HIGH PRESSURE WILL BEGIN TO EXERT ITS INFLUENCE ON OUR WEATHER
FRIDAY AND MORE SO SATURDAY INTO SUNDAY AS THIS WEATHER FEATURE WILL
EXTEND SW-NE ACROSS THE AREA. MAINLY CLEAR SKIES AND LIGHT WINDS
WILL BE ASSOCIATED WITH THE HIGH. THE HIGH WILL DRIFT EAST
MONDAY...SETTING UP A RETURN FLOW REGIME...LEADING TO MORE CLOUDS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...MWS
AVIATION...WSS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
834 AM MST THU MAR 7 2013
.UPDATE...
ISSUED AT 830 AM MST THU MAR 7 2013
15Z SURFACE ANALYSIS HAD WEAK LOW OVER NORTHEAST WY WITH GENTLE
COOL FRONT/TROUGH FROM CENTRAL MT INTO SOUTHWEST SD. MID/HIGH
CLOUDS STREAMING OVER CWA ON 90KT UPPER LEVEL JET...BUT THEY ARE
PARTIALLY TRANSPARENT. 12Z RAP MESHES WELL WITH CURRENT TRENDS.
WILL TWEAK TEMPERATURES WEST OF THE FRONT A COUPLE OF DEGREES UP
BASED ON 12Z RAP/KUNR SOUNDING...AND EAST OF THE FRONT A TAD LOWER
GIVEN UPSTREAM SURFACE TRAJECTORIES. REST OF FORECAST IN GOOD
SHAPE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 305 AM MST THU MAR 7 2013
WESTERN CONUS TROUGHING CONTINUES...SUPPORTING FAST
DISTURBED OVER THE LOCAL REGION. ASSOCIATED ADVECTING IMPULSE
CONTINUES TO PROPAGATE ENE ACROSS THE NORTHERN PLAINS...WITH AN
ASSOCIATED LL TROUGH REFLECTION. THIS IMPULSE WILL CONTINUE EAST
TODAY...SUPPORTING WEAK CAA IN IT/S WAKE. FLOW WILL QUICKLY RESPOND
TO THE NEXT ADVANCING SHORTWAVE TOUGH AS THE MAIN WESTERN CONUS
LONG WAVE TROUGH CONTINUES TO DIG SOUTH INTO THE SW CONUS. WAA WILL
AGAIN SPREAD OVER THE REGION FRIDAY AHEAD OF THE NEXT ADVANCING
DISTURBANCE...WITH LL FLOW RESPONDING TO ONGOING PRESSURE FALLS.
WEAK DEFORMATION ZONE WILL DEVELOP OVER PORTIONS OF NE WY AND
MT...AND EAST INTO NORTH DAKOTA....POSSIBLY SUPPORTING SOME LIGHT
PRECIP ACTIVITY LATE FRIDAY MORNING INTO FRIDAY AFTERNOON THERE.
LATEST GUIDANCE CONTINUES TO TREND THIS AREA OF LIFT NW...WITH ONLY
LOW TO MID RANGE CHANCE POPS RETAINED OVER THE NW FA.
OTHERWISE...ATTENTION TURNS TOWARD INCREASING LARGE SCALE ASCENT
WITH THE AFOREMENTIONED LEAD SHORTWAVE TROUGH. INCREASING LL
MOISTURE PER SE LL FLOW WILL SUPPORT SUFFICIENT LL MOISTURE FLUX FOR
RAIN/SNOW/WITH THE POTENTIAL FOR FREEZING RAIN REMAINING OVER
SCENTRAL SD INTO CENTRAL SD...GIVEN A STRONG ELEVATED WARM TONGUE
ADVANCING NW AHEAD OF THIS WAVE. MEANWHILE...AN EXPECTED NORTHERN
STREAM TROUGH WILL QUICKLY ADVECT INTO THE NORTHERN PLAINS LATER
FRIDAY NIGHT...SUPPORTING INCREASING LL CAA AND INDUCED LL PRESSURE
FALLS. THIS WAVE AND ASSOCIATED COLD FRONT WILL INTRODUCE ENOUGH
COLD AIR TO END ALL MIXED PRECIP CHANCES SAT MORNING...WITH SNOW
BEING THE DOMINANT PRECIP TYPE ALL PLACES AS THE MAIN SW CONUS UPPER
TROUGH BEGINS TO EJECT TOWARD THE REGION.
FORECAST MODELS ARE STILL WAVERING ON THE EXACT DETAILS PER THIS
EVOLUTION...WITH STILL MANY DETAILS TO BE WORKED OUT.
HOWEVER...CONFIDENCE HAS INCREASED THAT THERE WILL BE A PERIOD OF
MIXED PRECIP IN SCENTRAL SD FRIDAY NIGHT. STRONG WARM NOSE /2-3C/ IN
A THETA-E ADV REGIME WITH INCREASING LSA WILL BE MORE THAN AMPLE
TO SUPPORT PRECIP DEVELOPMENT. FORECAST MODELS SUGGEST UP TO A
QUARTER INCH QPF IN FAR SCENTRAL SD...MAINLY RAIN AT FIRST WITH A
PERIOD OF ICING LIKELY LATER /WHICH IS IN LINE WITH CURRENT SREF
PROGS/. ATTM IT DOES NOT APPEAR TO THAT SIG ICING IS EXPECTED
GIVEN A RATHER WARM BL THROUGH FRI NIGHT. HOWEVER...SOME SOLUTIONS
SUGGEST UP TO A TENTH OF INCH OF ICE ACCUMS IS POSSIBLE ESP AROUND
THE WINNER AREA. THIS WILL NEED TO BE WATCHED.
SMALL ADJUSTMENT MADE TO HIGH TEMPS...WHICH WILL BE TRICKY TODAY
GIVEN THE ADVANCING COLD FRONT AND ASSOCIATED CAA TIMING. STILL
EXPECT 50S AND SOME LOWER 60S WILL BE POSSIBLE IN SW SD...WITH TEMPS
ONLY REACHING THE 40S OVER NW SD AND NE WY. COOLER TEMPS EXPECTED
FRI.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 305 AM MST THU MAR 7 2013
LARGE UPPER LEVEL TROF WILL CROSS THE NORTHERN PLAINS THIS WEEKEND
WITH A RIDGE BUILDING IN FOR EARLY NEXT WEEK. POTENT SYSTEM WITHIN
THE TROF WILL CROSS THE CENTRAL PLAINS ON SATURDAY AND SUNDAY...WITH
THE NORTHERN EDGE OF THE SYSTEM BRINGING ACCUMULATING SNOWS TO
SOUTHERN PORTIONS OF THE FORECAST AREA.
LATEST MODEL RUNS CONTINUE TO SHOW UPPER LOW SWINGING THROUGH THE
FOUR CORNERS AREA VERY EARLY SATURDAY MORNING...AND TRACKING
EAST-NORTHEASTWARD THROUGH THE WEEKEND. MID LEVEL LOW DEVELOPS
ACROSS EASTERN COLORADO BY MIDDAY SATURDAY AS NORTHERN EDGE OF
PRECIP SHIELD SHIFTS NORTH INTO THE AREA. AMPLE MOISTURE AND
NORTHERLY BOUNDARY LAYER FLOW WILL ALSO BRING UPSLOPE SNOW TO THE
NORTHERN BLACK HILLS AREA SATURDAY AND SATURDAY EVENING. SYSTEM
QUICKLY SHIFTS EAST SATURDAY NIGHT...WITH SNOW TAPERING OFF BY EARLY
SUNDAY MORNING.
THE BEST CHANCES FOR SIGNIFICANT PCPN AMOUNTS WILL BE ACROSS FAR
SOUTHERN SD...ESPECIALLY SOUTH CENTRAL SD...AND ACROSS THE NORTHERN
BLACK HILLS. UP TO 6 INCHES OF SNOWFALL WILL BE POSSIBLE IN THESE
AREAS.
BEYOND THAT...TEMPERATURES WILL GRADUALLY WARM INTO EARLY NEXT WEEK
AS RIDGE BUILDS OVER THE WESTERN CONUS. MOSTLY DRY WEATHER IS
EXPECTED ACROSS THE AREA...BUT WILL KEEP SOME LOW CHANCES FOR RAIN
AND SNOW SHOWERS FOR MONDAY AFTERNOON INTO TUESDAY ACROSS PORTIONS
OF NORTHEASTERN WY AND INTO THE BLACK HILLS AS WEAK UPPER LEVEL
ENERGY PASSES OVER THE RIDGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 305 AM MST THU MAR 7 2013
VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE EXCEPTION
WILL BE ACROSS PARTS OF NORTHEAST WYOMING...WHERE SOME LIGHT SNOW
SHOWERS WILL BE POSSIBLE AFTER MIDNIGHT.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...15
AVIATION...15
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1007 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 9:10 AM PST THURSDAY...SATL IMAGERY IS INDC
THAT THE UPPER LOW IS WEST OF PT REYES AND IS SLOWLY MOVING
SOUTH...BUT WILL REMAIN OFF THE COAST. SO FAR...RADAR AND SFC OBS
ARE SHOWING ALL RAIN OFF THE COAST.
WITH THE TRACK OF THE UPPER LOW FCST TO BE WEST OF THE COAST...
THE CORE OF THE COLD AIR WILL REMAIN OVER THE OCEAN. THE QUESTION
THEN BECOMES WHAT TO DO WITH THE WINTER WEATHER ADVISORIES THAT
ARE CURRENTLY OUT FOR THE SOUTHERN MOUNTAINS. BASED ON THE LATEST
MODEL DATA IT APPEARS THAT THE SNOW LEVELS MIGHT BE HIGHER THAN
PREVIOUSLY EXPECTED. HOWEVER...ANY CONVECTIVE SHOWERS COULD DROP
THE SNOW LEVELS DOWN TEMPORARILY. BOTTOM LINE IS THAT THERE WAS
CONSIDERATION FOR DROPPING THE WINTER WEATHER ADVISORIES...HAVE
DECIDED TO LET THEM CONTINUE DUE TO THE POSSIBILITY OF CONVECTIVE
ACTIVITY DROPPING THE SNOW LEVELS LOW ENOUGH TO GET A QUICK COUPLE
OF INCHES OR MORE.
CURRENT FORECAST ON TRACK...NO UPDATES.
PREVIOUS DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST
FOCUS IS ON SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE
MENDOCINO. COMPARED TO 24 HOURS AGO THE MODELS ARE NOW BRINGING
THE MAIN CORE OF THE LOW CLOSER TO THE BAY AREA LATER THIS
AFTERNOON AND EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK
OF THE ENERGY AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS
SOUTHERN CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT
WAS ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH
THE MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE
NUMEROUS ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO
INCREASE THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW
APPROACHES THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR
PRECIP IN THE NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE
BULK OF THE SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD.
HIGHER CONFIDENCE THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE
FOCUSED OVER THE SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF
THE LOW WILL THEN DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS
WILL BE LIGHT WITH 0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW
STAYS OFF SHORE THE COLDEST AIR ALOFT WONT INFILTRATE THE
REGION...THUS SNOW LEVELS SHOULD GENERALLY STAY 3000 FEET AND
HIGHER. HAVE FINE TUNED THE INHERITED WINTER WX ADVISORY FOR THE
HIGHER TERRAIN OF MONTEREY AND SAN BENITO COUNTY TO DELAY THE
START AND SHORTEN THE END TIME TO THE PRE-DAWN HOURS OF TOMORROW.
THE MAIN PRECIP WILL WIND DOWN BY 12Z FRIDAY WITH JUST SOME
SCATTERED SHOWERS LEFT OVER ON FRIDAY MORNING FOR THE MONTEREY BAY
REGION...DECREASING TO ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 10:05 AM PST THURSDAY...CURRENTLY THE VISIBLE
SATELLITE IMAGE IS SHOWING A LOW PRESSURE SYSTEM POSITIONED JUST
OFF OF THE SONOMA COAST. THIS LOW PRESSURE SYSTEM IS ADVECTING MID
TO UPPER LEVEL CLOUDS INTO THE MONTEREY AND SAN FRANCISCO BAY
AREAS. SHOWERS WILL BECOME A POSSIBILITY THIS AFTERNOON AND
EVENING AS THE LOW MOVE SOUTH ALONG THE COAST.
VICINITY OF KSFO...VFR IS FORECAST TODAY WITH SOUTH SOUTHEAST
WINDS. SHOWERS ARE EXPECTED BY 0000Z WITH LIGHT RAIN BY 0500Z.
NORTH WINDS WILL FILL INTO THE BAY AREA BY 1000Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR IS FORECAST TODAY WITH SOUTHERLY WINDS.
SHOWERS WILL BE A POSSIBILITY BETWEEN 2100 AND 0000Z WITH LIGHT
RAIN BEGINNING AROUND 0000Z.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY
AND AND SAN BENITO COUNTY FROM 1 PM THURSDAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: STROBIN/RWW
AVIATION/MARINE: LARRY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
920 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 9:10 AM PST THURSDAY...SATL IMAGERY IS INDC
THAT THE UPPER LOW IS WEST OF PT REYES AND IS SLOWLY MOVING
SOUTH...BUT WILL REMAIN OFF THE COAST. SO FAR...RADAR AND SFC OBS
ARE SHOWING ALL RAIN OFF THE COAST.
WITH THE TRACK OF THE UPPER LOW FCST TO BE WEST OF THE COAST...
THE CORE OF THE COLD AIR WILL REMAIN OVER THE OCEAN. THE QUESTION
THEN BECOMES WHAT TO DO WITH THE WINTER WEATHER ADVISORIES THAT
ARE CURRENTLY OUT FOR THE SOUTHERN MOUNTAINS. BASED ON THE LATEST
MODEL DATA IT APPEARS THAT THE SNOW LEVELS MIGHT BE HIGHER THAN
PREVIOUSLY EXPECTED. HOWEVER...ANY CONVECTIVE SHOWERS COULD DROP
THE SNOW LEVELS DOWN TEMPORARILY. BOTTOM LINE IS THAT THERE WAS
CONSIDERATION FOR DROPPING THE WINTER WEATHER ADVISORIES...HAVE
DECIDED TO LET THEM CONTINUE DUE TO THE POSSIBILITY OF CONVECTIVE
ACTIVITY DROPPING THE SNOW LEVELS LOW ENOUGH TO GET A QUICK COUPLE
OF INCHES OR MORE.
CURRENT FORECAST ON TRACK...NO UPDATES.
PREVIOUS DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST
FOCUS IS ON SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE
MENDOCINO. COMPARED TO 24 HOURS AGO THE MODELS ARE NOW BRINGING
THE MAIN CORE OF THE LOW CLOSER TO THE BAY AREA LATER THIS
AFTERNOON AND EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK
OF THE ENERGY AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS
SOUTHERN CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT
WAS ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH
THE MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE
NUMEROUS ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO
INCREASE THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW
APPROACHES THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR
PRECIP IN THE NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE
BULK OF THE SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD.
HIGHER CONFIDENCE THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE
FOCUSED OVER THE SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF
THE LOW WILL THEN DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS
WILL BE LIGHT WITH 0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW
STAYS OFF SHORE THE COLDEST AIR ALOFT WONT INFILTRATE THE
REGION...THUS SNOW LEVELS SHOULD GENERALLY STAY 3000 FEET AND
HIGHER. HAVE FINE TUNED THE INHERITED WINTER WX ADVISORY FOR THE
HIGHER TERRAIN OF MONTEREY AND SAN BENITO COUNTY TO DELAY THE
START AND SHORTEN THE END TIME TO THE PRE-DAWN HOURS OF TOMORROW.
THE MAIN PRECIP WILL WIND DOWN BY 12Z FRIDAY WITH JUST SOME
SCATTERED SHOWERS LEFT OVER ON FRIDAY MORNING FOR THE MONTEREY BAY
REGION...DECREASING TO ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 3:50 AM PST THURSDAY...A STORM SYSTEM IS
FORECAST TO MOVE TOWARD THE REGION LATER THIS MORNING. THIS STORM
WILL BRING RAIN SHOWERS TO THE TERMINALS...MAINLY IMPACTING KSJC
SOUTHWARD. MAINLY LIGHT AND VARIABLE WINDS ALONG WITH VFR CIGS
WILL ACCOMPANY THIS STORM. SHOWER ACTIVITY WILL SUBSIDE THIS
EVENING INTO THE OVERNIGHT HOURS.
VICINITY OF KSFO...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST. RAIN SHOWERS ARE FORECAST TO IMPACT THE BAY BY
17Z...WITH A STRAY SHOWER POSSIBLE BEFORE THIS TIME. LIGHT
SOUTHERLY WINDS WILL BECOME WESTERLY BY THIS AFTERNOON. RAIN
SHOWER ACTIVITY WILL MOVE OUT OF THE REGION BY 10Z FRIDAY.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH
THE FORECAST. RAIN SHOWER ACTIVITY WILL INCREASE EARLY THIS
AFTERNOON AND CONTINUE THROUGH THE OVERNIGHT HOURS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY AND
AND SAN BENITO COUNTY FROM 1 PM TODAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: STROBIN/RWW
AVIATION/MARINE: LARRY/RILEY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
138 PM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
//PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SLIGHT CHANCE FOR VIS RESTRICTIONS IN BR EARLY FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN ISSUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS
EVENING WILL BE CEILINGS. THE LOWER END VFR STRATOCU DECK REMAINS
IN PLACE OVER MUCH OF THE AREA...LOWERING TO HIGH END MVFR CIGS
WEST OF THE CHICAGO AREA INCLUDING RFD. A CLEARING SLOT HAD PUSHED
SOUTH OVER FAR NERN IL THIS MORNING...ALLOWING ORD TO BRIEFLY
IMPROVE TO SCT035...BUT THE STRATOCU HAS FILLED BACK TO BKN-
OVC035. WHILE THE LATEST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE CLOUD IS VERY THIN...WITH SFC FEATURES SHOWING THROUGH THE
CLOUD COVER...THE 11-3.9 MICRON IMAGERY MUCH BETTER SHOWS THE
EXTENT OF THE CLOUD COVER...WITH LATEST TRENDS INDICATING NO
TREND OF CLOUD COVER TO IMPROVE. ALSO...MODEL SOUNDING CONTINUE TO
INDICATE A WEAK INVERSION IN PLACE THROUGH THE AFTERNOON AND THIS
EVENING...SO DO NOT EXPECT ANY DEEP LAYER MIXING TO HELP BREAK UP
THE CLOUD COVER. WITH THE SFC RIDGE MOVING ACROSS THE
AREA...EXPECT THAT WINDS WILL BE LGT/VRBL TO CALM THROUGH MUCH OF
THE PERIOD...BEFORE BECOMING MORE SELY AND STRENGTHENING TOMORROW
MORNING AS THE SFC RIDGE PUSHES TO THE EAST. HAVE SOME CONCERN FOR
REDUCED VISBY IN BR/FG OVERNIGHT TONIGHT WITH LIGHT WINDS AND
DECREASING CLOUD COVER. HOWEVER...CONFIDENCE IS NOT HIGH IN THE
CLOUD COVER TRENDS. ALSO...SFC DEWPOINTS ARE EXPECTED TO REMAIN
FAIRLY LOW...SO DO NOT HAVE HIGH ENOUGH CONFIDENCE IN THE
POTENTIAL FOR REDUCED VISBY TONIGHT TO INCLUDE IN THE TAFS JUST
YET.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOW PACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* LOW CONFIDENCE ON TIMING SCATTERING OF THE STRATOCU DECK...AND
THE POTENTIAL FOR BR/FG LATE TONIGHT INTO EARLY TOMORROW
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
1245 PM CST
SURFACE HIGH PRESSURE RIDGING STRETCHING FROM ONTARIO SOUTH ACROSS
WISCONSIN AND ILLINOIS WILL CONTINUE TO DRIFT EAST ACROSS LAKE
MICHIGAN THROUGH FRIDAY. DECREASING LIGHT NORTH WINDS WILL BECOME
SOUTHEAST ON FRIDAY...INCREASING MODESTLY FRIDAY NIGHT AND BECOMING
MORE SOUTHERLY AS LOW PRESSURE DEVELOPS AND DEEPENS ACROSS THE HIGH
PLAINS TO THE WEST.
LOW PRESSURE WILL LIFT NORTHEAST ACROSS THE CENTRAL PLAINS ON
SATURDAY...WITH THE SURFACE PRESSURE GRADIENT ACROSS THE WESTERN
LAKES TIGHTENING IN RESPONSE TO THE DEVELOPMENT AND APPROACH OF THE
LOW. WITH RELATIVELY MILD SOUTHERLY FLOW ACROSS THE AREA...FORECAST
SOUNDINGS INDICATE THAT LOW LEVEL LAPSE RATES WILL NOT BE
PARTICULARLY STEEP...AND SUPPORT WINDS INCREASING TO 20-25 KT FOR
THE MOST PART SATURDAY AFTERNOON AND NIGHT WITH PERHAPS SOME GUSTS
AROUND 30 KT. STRONGER WINDS...GALES IN THE 35-45 KT RANGE...WILL
EXIST JUST 1000 FT AGL...THOUGH THE WEAK LAPSE RATES SUGGEST IT MAY
BE TOUGH TO MIX THESE WINDS TO THE SURFACE WITH THE AIR BECOMING
WARMER THAN THE LAKE SURFACE.
THE GENERAL TREND IN FORECAST MODEL GUIDANCE OVER THE PAST FEW RUNS
HAS BEEN TO WEAKEN THE LOW AS IT MOVES INTO THE WESTERN LAKES REGION
EARLY SUNDAY...WHICH SHOULD ALLOW SOUTH WINDS TO WEAKEN LATE
SATURDAY NIGHT OR SUNDAY MORNING AS THE GRADIENT WEAKENS AND BECOMES
BAGGY WITH THE SURFACE TROUGH/LOW APPROACH FROM THE WEST/SOUTHWEST.
SOUTH WINDS ARE THUS EXPECTED TO DIMINISH AND THEN VEER TO THE NORTH
DURING THE DAY SUNDAY AS THE TROUGH/COLD FRONT PASS. NORTH WINDS
THEN LOOK TO INCREASE BEHIND THE FRONT...AS THE GRADIENT TIGHTENS
AGAIN AHEAD OF HIGH PRESSURE SPREADING ACROSS ONTARIO AND THE UPPER
MIDWEST...AND WITH COLDER AIR BEHIND THE FRONT PRODUCING MUCH
STEEPER LOW LEVEL LAPSE RATES ALLOWING MIXING OF STRONGER WINDS TO
THE SURFACE. NORTH WINDS TO 30 KTS APPEAR TO BE A FAIRLY HIGH
PROBABILITY SUNDAY AFTERNOON AND NIGHT...WITH THE POTENTIAL FOR
NORTH GALES. WINDS THEN DECREASE MONDAY AS THE SURFACE RIDGE
APPROACHES.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1246 PM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
//PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SLIGHT CHANCE FOR VIS RESTRICTIONS IN BR EARLY FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN ISSUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS
EVENING WILL BE CEILINGS. THE LOWER END VFR STRATOCU DECK REMAINS
IN PLACE OVER MUCH OF THE AREA...LOWERING TO HIGH END MVFR CIGS
WEST OF THE CHICAGO AREA INCLUDING RFD. A CLEARING SLOT HAD PUSHED
SOUTH OVER FAR NERN IL THIS MORNING...ALLOWING ORD TO BRIEFLY
IMPROVE TO SCT035...BUT THE STRATOCU HAS FILLED BACK TO BKN-
OVC035. WHILE THE LATEST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE CLOUD IS VERY THIN...WITH SFC FEATURES SHOWING THROUGH THE
CLOUD COVER...THE 11-3.9 MICRON IMAGERY MUCH BETTER SHOWS THE
EXTENT OF THE CLOUD COVER...WITH LATEST TRENDS INDICATING NO
TREND OF CLOUD COVER TO IMPROVE. ALSO...MODEL SOUNDING CONTINUE TO
INDICATE A WEAK INVERSION IN PLACE THROUGH THE AFTERNOON AND THIS
EVENING...SO DO NOT EXPECT ANY DEEP LAYER MIXING TO HELP BREAK UP
THE CLOUD COVER. WITH THE SFC RIDGE MOVING ACROSS THE
AREA...EXPECT THAT WINDS WILL BE LGT/VRBL TO CALM THROUGH MUCH OF
THE PERIOD...BEFORE BECOMING MORE SELY AND STRENGTHENING TOMORROW
MORNING AS THE SFC RIDGE PUSHES TO THE EAST. HAVE SOME CONCERN FOR
REDUCED VISBY IN BR/FG OVERNIGHT TONIGHT WITH LIGHT WINDS AND
DECREASING CLOUD COVER. HOWEVER...CONFIDENCE IS NOT HIGH IN THE
CLOUD COVER TRENDS. ALSO...SFC DEWPOINTS ARE EXPECTED TO REMAIN
FAIRLY LOW...SO DO NOT HAVE HIGH ENOUGH CONFIDENCE IN THE
POTENTIAL FOR REDUCED VISBY TONIGHT TO INCLUDE IN THE TAFS JUST
YET.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOW PACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW CONFIDENCE ON TIMING SCATTERING OF THE STRATOCU DECK...AND
THE POTENTIAL FOR BR/FG LATE TONIGHT INTO EARLY TOMORROW
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
1245 PM CST
SURFACE HIGH PRESSURE RIDGING STRETCHING FROM ONTARIO SOUTH ACROSS
WISCONSIN AND ILLINOIS WILL CONTINUE TO DRIFT EAST ACROSS LAKE
MICHIGAN THROUGH FRIDAY. DECREASING LIGHT NORTH WINDS WILL BECOME
SOUTHEAST ON FRIDAY...INCREASING MODESTLY FRIDAY NIGHT AND BECOMING
MORE SOUTHERLY AS LOW PRESSURE DEVELOPS AND DEEPENS ACROSS THE HIGH
PLAINS TO THE WEST.
LOW PRESSURE WILL LIFT NORTHEAST ACROSS THE CENTRAL PLAINS ON
SATURDAY...WITH THE SURFACE PRESSURE GRADIENT ACROSS THE WESTERN
LAKES TIGHTENING IN RESPONSE TO THE DEVELOPMENT AND APPROACH OF THE
LOW. WITH RELATIVELY MILD SOUTHERLY FLOW ACROSS THE AREA...FORECAST
SOUNDINGS INDICATE THAT LOW LEVEL LAPSE RATES WILL NOT BE
PARTICULARLY STEEP...AND SUPPORT WINDS INCREASING TO 20-25 KT FOR
THE MOST PART SATURDAY AFTERNOON AND NIGHT WITH PERHAPS SOME GUSTS
AROUND 30 KT. STRONGER WINDS...GALES IN THE 35-45 KT RANGE...WILL
EXIST JUST 1000 FT AGL...THOUGH THE WEAK LAPSE RATES SUGGEST IT MAY
BE TOUGH TO MIX THESE WINDS TO THE SURFACE WITH THE AIR BECOMING
WARMER THAN THE LAKE SURFACE.
THE GENERAL TREND IN FORECAST MODEL GUIDANCE OVER THE PAST FEW RUNS
HAS BEEN TO WEAKEN THE LOW AS IT MOVES INTO THE WESTERN LAKES REGION
EARLY SUNDAY...WHICH SHOULD ALLOW SOUTH WINDS TO WEAKEN LATE
SATURDAY NIGHT OR SUNDAY MORNING AS THE GRADIENT WEAKENS AND BECOMES
BAGGY WITH THE SURFACE TROUGH/LOW APPROACH FROM THE WEST/SOUTHWEST.
SOUTH WINDS ARE THUS EXPECTED TO DIMINISH AND THEN VEER TO THE NORTH
DURING THE DAY SUNDAY AS THE TROUGH/COLD FRONT PASS. NORTH WINDS
THEN LOOK TO INCREASE BEHIND THE FRONT...AS THE GRADIENT TIGHTENS
AGAIN AHEAD OF HIGH PRESSURE SPREADING ACROSS ONTARIO AND THE UPPER
MIDWEST...AND WITH COLDER AIR BEHIND THE FRONT PRODUCING MUCH
STEEPER LOW LEVEL LAPSE RATES ALLOWING MIXING OF STRONGER WINDS TO
THE SURFACE. NORTH WINDS TO 30 KTS APPEAR TO BE A FAIRLY HIGH
PROBABILITY SUNDAY AFTERNOON AND NIGHT...WITH THE POTENTIAL FOR
NORTH GALES. WINDS THEN DECREASE MONDAY AS THE SURFACE RIDGE
APPROACHES.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1141 AM CST THU MAR 7 2013
.DISCUSSION...
ISSUED 951 AM CST THU MAR 7 2013
CLOUDS CONTINUE TO PLAGUE CENTRAL AND SOUTHEAST ILLINOIS THIS
MORNING...THANKS TO MOISTURE TRAPPED BENEATH A STRONG LOW-LEVEL
SUBSIDENCE INVERSION. LATEST VISIBLE SATELLITE IMAGERY SHOWS A
RATHER THIN OVERCAST ACROSS THE REGION...WITH MAJOR RIVERS DIMLY
VISIBLE THROUGH THE CLOUD COVER. GIVEN RELATIVE THINNESS OF CLOUDS
AND STRENGTH OF EARLY MARCH SUN...THINK A FEW HOLES WILL BE
PUNCHED IN THE OVERCAST AS THE DAY GOES ON. HOWEVER...WITH STRONG
INVERSION IN PLACE AND LITTLE OR NO WIND...EXPECT GENERALLY CLOUDY
CONDITIONS THROUGH THE DAY. WINDS WILL BECOME LIGHT AND EASTERLY
LATER TODAY/TONIGHT...AS SURFACE HIGH SHIFTS INTO THE OHIO RIVER
VALLEY. THIS MAY TEND TO ADVECT LOW-LEVEL MOISTURE BACK INTO THE
AREA TONIGHT. WHILE 12Z NAM FORECAST SOUNDINGS INDICATE CLEARING
BY EVENING...14Z RUC SOUNDINGS MAY HAVE A BETTER HANDLE ON
REALITY...INDICATING MOSTLY CLOUDY CONDITIONS PERSISTING THROUGH
THE NIGHT.
&&
.AVIATION...
ISSUED 1141 AM CST THU MAR 7 2013
CLOUDS CONTINUE TO BLANKET CENTRAL ILLINOIS LATE THIS
MORNING...HOWEVER EARLY MARCH SUN IS BEGINNING TO ERODE THE W/SW
EDGE OF THE OVERCAST. SINCE CLOUDS ARE RELATIVELY THIN...THINK
THIS PROCESS WILL CONTINUE FOR THE NEXT 3 TO 4 HOURS. AS A
RESULT...HAVE SCATTERED THE MVFR CEILINGS AT KSPI BY 19Z AND AT
KPIA BY 20Z. WILL KEEP AN EYE ON SATELLITE TRENDS FOR POTENTIAL
CLEARING FURTHER EASTWARD...BUT FOR NOW HAVE OPTED TO CONTINUE THE
CEILINGS AT THE REMAINING TERMINALS THROUGHOUT THE AFTERNOON. ONCE
THE SUN SETS AND LOW-LEVEL FLOW TAKES ON A LIGHT EASTERLY
COMPONENT...THINK MOISTURE WILL ADVECT BACK WESTWARD...RESULTING
IN CLOUDY CONDITIONS THROUGH THE NIGHT. AS SURFACE HIGH PRESSURE
SLIDES FURTHER EASTWARD AND WINDS BEGIN TO INCREASE FROM THE
SOUTHEAST...SKIES WILL FINALLY CLEAR OUT ACROSS THE BOARD BY
FRIDAY MORNING.
BARNES
&&
.PREV DISCUSSION...
ISSUED 307 AM CST THU MAR 7 2013
EARLY MORNING SURFACE MAP SHOWED HIGH PRESSURE RIDGING RUNNING THE
LENGTH OF THE MISSISSIPPI RIVER. RATHER TIGHT INVERSION JUST ABOVE
900 MB HAS PUT THE KIBOSH ON ANY REAL EROSION OF THE LARGE
STRATOCUMULUS DECK OVER MUCH OF THE MIDWEST...WITH ONLY AREAS
AROUND JACKSONVILLE SEEING ANY SUSTAINED CLEARING AND THAT HAS
BEGUN TO FILL IN AS WELL. THE CLOUDS HAVE KEPT TEMPERATURES IN THE
20S...WHICH IS GOOD SINCE CLEAR SKIES OVER THE SUBSTANTIAL SNOW
COVER IN THE NORTHERN CWA WOULD HAVE LIKELY RESULTED IN SINGLE
DIGITS AND TEENS IN THAT AREA. LOOKING UPSTAIRS...LATEST WATER
VAPOR IMAGERY SHOWING SEVERAL CIRCULATIONS IN A BROAD AREA OF 500
MB LOW PRESSURE OVER THE PACIFIC NORTHWEST. DEVELOPMENT OF THIS
PARTICULAR FEATURE WILL BE OF INTEREST TO OUR FORECAST FOR THE
WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY...
FAIRLY QUIET WEATHER EXPECTED IN THE SHORT TERM...AS THE HIGH
PUSHES EAST ACROSS THE GREAT LAKES. FORECAST SOUNDINGS SHOW THE
INVERSION SLOW TO ERODE THOUGH...SO WILL KEEP THE EASTERN CWA
FAIRLY CLOUDY TODAY AND TRY TO MARK SOME CLEARING ACROSS THE WEST
BY MIDDAY. MAIN CONCERN WILL BE WITH FOG POTENTIAL TONIGHT ACROSS
THE NORTH...WITH WINDS STILL FAIRLY LIGHT AND SOME POTENTIAL FOR
SNOW MELT TODAY. SHOULD SKIES STAY CLOUDY...THIS WOULD BE LESS OF
A CONCERN.
TEMPERATURE-WISE...WILL CONTINUE THE TREND OF KEEPING HIGHS A FEW
DEGREES COOLER ACROSS THE NORTH WHERE THE SNOW DEPTH RANGES FROM 5
TO 9 INCHES. HOWEVER...EVEN THESE AREAS MAY CRACK 40 BY FRIDAY...
WITH HIGHS 45-50 FURTHER SOUTH.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
UPPER LOW IN THE PACIFIC NORTHWEST SHOULD BETTER ORGANIZE AS IT
DROPS SOUTHWARD ALONG THE CALIFORNIA COAST TONIGHT AND FRIDAY.
LATEST MODEL GUIDANCE CONTINUES TO EJECT THIS FEATURE NORTHEAST
THIS WEEKEND...AS A DEEPENING SHORTWAVE TRACKS EAST ACROSS THE
CANADIAN PRAIRIES. SOME PHASING OF THE TWO FEATURES IS INDICATED
LATER THIS WEEKEND OVER THE CENTRAL U.S. AND THIS WILL
SIGNIFICANTLY INCREASE PRECIP CHANCES AS THE WEEKEND PROGRESSES.
GOOD MOISTURE SURGE SHOULD TAKE PLACE AHEAD OF THIS PHASING...
WITH GFS PRECIPITABLE WATER VALUES OF 1.25 INCHES SATURDAY NIGHT
NEAR THE 99TH PERCENTILE FOR EARLY MARCH. WOULD NOT BE SURPRISED
TO SEE OVER AN INCH OF RAIN IN SOME AREAS SATURDAY NIGHT THROUGH
SUNDAY NIGHT. HAVE INTRODUCED CATEGORICAL RAIN CHANCES SATURDAY
NIGHT NORTHWEST OF THE ILLINOIS RIVER...AND ALSO ADDED AREAS OF
FOG ACROSS THE NORTHERN CWA DUE TO THE HEAVIER RAIN AND RAPID SNOW
MELT. SUNDAY WILL START OUT RATHER WET AS WELL. HOWEVER...THE
MODELS BEGIN TO DIVERGE IN TERMS OF WHETHER A DRY SLOT MAY SPREAD
IN DURING THE DAY. WITH THE DIVERSITY...WILL NOT TRY TO GET TOO
CUTE WITH SPLITTING OUT MORNING AND AFTERNOON PERIODS.
TEMPERATURES BOTH DAYS SHOULD REACH WELL INTO THE 50S.
SUNDAY NIGHT AND MONDAY...THE GFS AND ECMWF MODELS BOTH SHOW THE
NORTHERN WAVE EXITING THE AREA...WHILE ANOTHER LOW DEVELOPS OVER
THE SOUTHERN PLAINS. THE GFS IS MORE AGGRESSIVE WITH CLOSING THIS
LOW OFF AND LIFTING IT NORTHEAST...WHILE THE ECMWF WEAKENS BACK
INTO AN OPEN WAVE. LEANING MORE TOWARD THE ECMWF SOLUTION FOR
NOW...AND HAVE LIMITED LIKELY POPS SUNDAY NIGHT TO THE SOUTHEAST
THIRD OF THE CWA. HAVE KEPT SOME PRECIP CHANCES IN ON MONDAY FOR
NOW...BUT CONFIDENCE IS LOW AT THE MOMENT. HAVE LARGELY KEPT THE
PRECIP AS RAIN EXCEPT FOR A MIX IN THE NORTHWEST.
MODEL AGREEMENT DOES NOT IMPROVE AS THE WEEK PROGRESSES...WITH THE
LONGER RANGE SOLUTIONS VARYING WITH THE STRENGTH OF ANOTHER WAVE
DROPPING INTO THE GREAT LAKES ON TUESDAY. THE ECMWF SOLUTION WOULD
BE MUCH COOLER FOR US WITH SIGNIFICANT RIDGING WEST OF THE
ROCKIES. FOR NOW HAVE KEPT TEMPERATURES ABOUT 5 DEGREES BELOW
NORMAL FOR THE END OF THE FORECAST PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1127 AM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
//PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SLIGHT CHANCE FOR VIS RESTRICTIONS IN BR EARLY FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN ISSUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS
EVENING WILL BE CEILINGS. THE LOWER END VFR STRATOCU DECK REMAINS
IN PLACE OVER MUCH OF THE AREA...LOWERING TO HIGH END MVFR CIGS
WEST OF THE CHICAGO AREA INCLUDING RFD. A CLEARING SLOT HAD PUSHED
SOUTH OVER FAR NERN IL THIS MORNING...ALLOWING ORD TO BRIEFLY
IMPROVE TO SCT035...BUT THE STRATOCU HAS FILLED BACK TO BKN-
OVC035. WHILE THE LATEST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE CLOUD IS VERY THIN...WITH SFC FEATURES SHOWING THROUGH THE
CLOUD COVER...THE 11-3.9 MICRON IMAGERY MUCH BETTER SHOWS THE
EXTENT OF THE CLOUD COVER...WITH LATEST TRENDS INDICATING NO
TREND OF CLOUD COVER TO IMPROVE. ALSO...MODEL SOUNDING CONTINUE TO
INDICATE A WEAK INVERSION IN PLACE THROUGH THE AFTERNOON AND THIS
EVENING...SO DO NOT EXPECT ANY DEEP LAYER MIXING TO HELP BREAK UP
THE CLOUD COVER. WITH THE SFC RIDGE MOVING ACROSS THE
AREA...EXPECT THAT WINDS WILL BE LGT/VRBL TO CALM THROUGH MUCH OF
THE PERIOD...BEFORE BECOMING MORE SELY AND STRENGTHENING TOMORROW
MORNING AS THE SFC RIDGE PUSHES TO THE EAST. HAVE SOME CONCERN FOR
REDUCED VISBY IN BR/FG OVERNIGHT TONIGHT WITH LIGHT WINDS AND
DECREASING CLOUD COVER. HOWEVER...CONFIDENCE IS NOT HIGH IN THE
CLOUD COVER TRENDS. ALSO...SFC DEWPOINTS ARE EXPECTED TO REMAIN
FAIRLY LOW...SO DO NOT HAVE HIGH ENOUGH CONFIDENCE IN THE
POTENTIAL FOR REDUCED VISBY TONIGHT TO INCLUDE IN THE TAFS JUST
YET.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOW PACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW CONFIDENCE ON TIMING SCATTERING OF THE STRATOCU DECK...AND
THE POTENTIAL FOR BR/FG LATE TONIGHT INTO EARLY TOMORROW
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1007 AM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
&&
.PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* POTENTIAL FOR FOG FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 12Z...
VFR STRATUS DECK REMAINS IN PLACE OVER THE CHICAGO AREA WITH HIGH
END MVFR CIGS WEST OF THE CHICAGO AREA INCLUDING RFD. GUIDANCE IS
NOT HANDLING THE SITUATION WELL NOR HOW LONG TO HANG ONTO THE CIGS
THROUGH THE DAY. HAVE TRENDED SLOWER WITH CLEARING AS COLD BOUNDARY
LAYER UNDERNEATH A MODERATE INVERSION MAY KEEP MOISTURE LOCKED IN
THROUGH THE DAY. THERE IS SUBTLE COOLING NOTED AT 925MB THIS
AFTERNOON WHICH MODEL SOUNDINGS SUGGEST MAY LEAD TO LOWERING MVFR
CIGS AROUND 020...HOWEVER THINK THE MODELS ARE LIKELY OVERDOING THE
DIURNAL HEATING COMPONENT TODAY AND RESULTANT LAPSE RATES...AND
DO NOT HAVE CONFIDENCE IN THIS SCENARIO PANNING OUT. WILL STICK WITH
SCT020 IN THE MEANTIME. WINDS ARE EXPECTED TO REMAIN LESS THAN 10 KT
THROUGH THE DAY...AND SHOULD GRADUALLY VEER FROM NW THIS MORNING TO
EASTERLY OVERNIGHT.
IN THE EVENT WE DO CLEAR OUT TODAY...WILL THEN HAVE TO KEEP AN EYE
ON THE FOG POTENTIAL. CONCEPTUALLY...LIGHT WINDS CLOSE TO THE RIDGE
AXIS...PERHAPS SOME ADDITIONAL BL MOISTURE WITH TEMPS PEAKING ABOVE
FREEZING THIS AFTERNOON HELPING TO MELT SOME OF THE SNOW...AND CLEAR
SKIES/FRESH SNOW SHOULD ALL LEAD TO STRONG RADIATIONAL COOLING AND
ENHANCED FOG POTENTIAL. DENSE FOG WAS OBSERVED OVERNIGHT TO OUR
WEST. BUT FOR NOW...BANKING ON CLOUDY SKIES STICKING AROUND TODAY
MINIMIZING THE FOG THREAT.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOWPACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW CONFIDENCE ON TIMING CLEARING OF VFR CIGS...AND RESULTING
FOG POTENTIAL OVERNIGHT.
* MMEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1122 AM CST THU MAR 7 2013
.UPDATE...
THE STRONGER MARCH SUN HAS STARTED TO ERODE THE LOW CLOUDS OVER
THE SOUTHWEST PART OF THE CWFA WITH SOME ADDITIONAL INROADS ACROSS
THE FAR SOUTH. IF CURRENT SATELLITE TRENDS HOLD...THE NORTHWEST
MOVEMENT OF THE CLOUDS APPEARS TO HAVE REACHED ITS MAXIMUM AND
THERE SHOULD BE A SLOW EROSION AROUND THE EDGES DURING THE
AFTERNOON. ..08..
&&
.AVIATION...
CURRENT 1-2KFT AGL CLOUDS ARE NOT BEING HANDLED WELL BY ANY MODEL.
WEAK SOUTHEAST FLOW IN THE LOW LEVELS HAS ADVECTED THE CLOUDS
NORTHWEST BUT THE STRONGER MARCH SUN MAY HAVE STOPPED THE
NORTHWEST MOVEMENT. MVFR CONDITIONS WILL BE SEEN AT KDBQ/KMLI/KBRL
WITH AN EVENTUAL IMPROVEMENT TO VFR EITHER PRIOR TO 00Z/08 OR BY
12Z/08. KCID SHOULD REMAIN VFR BUT MAY HAVE BRIEF INCURSIONS OF
MVFR THROUGH 21Z/07. ..08..
&&
.PREV DISCUSSION... /ISSUED 1012 AM CST THU MAR 7 2013/
UPDATE...
BASED ON DATA THROUGH MID MORNING WILL BE DOING A SIGNIFICANT
REVISION TO THE FCST FOR CLOUDS.
12Z UA DATA HAS A VERY THIN LAYER OF MOISTURE IN THE SOUNDINGS
TRAPPED BELOW THE INVERSION. THIS LAYER IS ON THE ORDER OF 200-300
FT THICK AND IS ROUGHLY 0.75 TO 0.90 KM ABOVE THE GROUND. THE RAP
MODEL AT LEAST HAS CLOUDS BUT THEY ARE TOO LOW IN THE FCST
SOUNDINGS.
THE RAP TRENDS AT THE 0.5 AND 1 KM LEVELS SHOW VERY WEAK SOUTHEAST
TO SOUTH SOUTHEAST FLOW WITH A SLOW UPGLIDE ON THE CONDENSATION
PRESSURE LEVELS. ADD TO THIS WAA OCCURRING ALOFT AND THE INVERSION
SHOULD ONLY STRENGTHEN DURING THE DAY. THE STRONGER MARCH SUN
SHOULD ALLOW SOME BREAKS TO DEVELOP IN THE CLOUDS BUT THE OVERALL
SIGNAL SUGGESTS THAT CLOUDS WILL REMAIN ACROSS THE AREA.
RECENT SATELLITE TRENDS ARE SHOWING A SLOW DRIFT TO THE NORTHWEST
WITH THE LOW CLOUDS AS HIGHER CLOUDS MOVE IN FROM THE WEST. THIS
TREND WITH THE LOW CLOUDS WILL LIKELY CONTINUE FOR SEVERAL MORE
HOURS AND MAY EVENTUALLY STOP. ANY CLEARING THAT OCCURS TODAY WILL
BE FROM THE SOUTH AND WILL BE VERY SLOW.
THE CLOUD COVER WILL THEN HAVE AN IMPACT ON TEMPERATURES WITH A
POTENTIAL SLIGHT LOWERING OF HIGHS FOR AREAS UNDER THE CLOUDS.
IF THE RAP TRENDS ARE CORRECT...THE CLOUDS MAY PERSIST INTO
TONIGHT. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1012 AM CST THU MAR 7 2013
.UPDATE...
BASED ON DATA THROUGH MID MORNING WILL BE DOING A SIGNIFICANT
REVISION TO THE FCST FOR CLOUDS.
12Z UA DATA HAS A VERY THIN LAYER OF MOISTURE IN THE SOUNDINGS
TRAPPED BELOW THE INVERSION. THIS LAYER IS ON THE ORDER OF 200-300
FT THICK AND IS ROUGHLY 0.75 TO 0.90 KM ABOVE THE GROUND. THE RAP
MODEL AT LEAST HAS CLOUDS BUT THEY ARE TOO LOW IN THE FCST
SOUNDINGS.
THE RAP TRENDS AT THE 0.5 AND 1 KM LEVELS SHOW VERY WEAK SOUTHEAST
TO SOUTH SOUTHEAST FLOW WITH A SLOW UPGLIDE ON THE CONDENSATION
PRESSURE LEVELS. ADD TO THIS WAA OCCURRING ALOFT AND THE INVERSION
SHOULD ONLY STRENGTHEN DURING THE DAY. THE STRONGER MARCH SUN
SHOULD ALLOW SOME BREAKS TO DEVELOP IN THE CLOUDS BUT THE OVERALL
SIGNAL SUGGESTS THAT CLOUDS WILL REMAIN ACROSS THE AREA.
RECENT SATELLITE TRENDS ARE SHOWING A SLOW DRIFT TO THE NORTHWEST
WITH THE LOW CLOUDS AS HIGHER CLOUDS MOVE IN FROM THE WEST. THIS
TREND WITH THE LOW CLOUDS WILL LIKELY CONTINUE FOR SEVERAL MORE
HOURS AND MAY EVENTUALLY STOP. ANY CLEARING THAT OCCURS TODAY WILL
BE FROM THE SOUTH AND WILL BE VERY SLOW.
THE CLOUD COVER WILL THEN HAVE AN IMPACT ON TEMPERATURES WITH A
POTENTIAL SLIGHT LOWERING OF HIGHS FOR AREAS UNDER THE CLOUDS.
IF THE RAP TRENDS ARE CORRECT...THE CLOUDS MAY PERSIST INTO
TONIGHT. ..08..
&&
.PREV DISCUSSION... /ISSUED 547 AM CST THU MAR 7 2013/
SYNOPSIS...
ISSUED AT 341 AM CST THU MAR 7 2013
ANOTHER RELATIVELY QUIET MORNING ACROSS THE AREA WITH THE STRONG
SURFACE RIDGE OVER THE FORECAST AREA. STRATUS LINGERS OVER THE
FORECAST AREA NEAR AND EAST OF THE SURFACE RIDGE. WHERE THE
STRATUS HAS CLEARED OUT...PATCHY TO AREAS OF FOG HAVE
DEVELOPED...MAINLY OVER THE NORTHERN PORTIONS OF EASTERN IOWA
WHERE THE STRATUS CLEARED EARLY IN THE EVENING. CLOSER TO THE
WESTERN EDGE OF THE STRATUS THE FOG IS LESS. THE FOG HAS NOT BEEN
CONSISTENT IN AREAL COVERAGE...WITH SITES VARYING WIDELY IN
VISIBILITY OVER THE LAST FEW HOURS. ALOFT...WE HAVE RIDGING AT
NEARLY ALL LEVELS OVER THE MIDWEST WITH VERY DRY 850MB AIR OVER
THE AREA. THE STORM THAT BROUGHT SNOW TO THE AREA TUESDAY IS NOW
JUST OFF THE EAST COAST. ..LE..
SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CST THU MAR 7 2013
DECEPTIVELY QUIET FORECAST WITH THE MAIN CONCERNS OVER THE FOG EARLY
THIS MORNING...THE EXPECTED GRADUAL DIMINISHING OF THE
STRATUS...AND TEMPERATURES TODAY AND TONIGHT.
THIS MORNINGS FOG IS A CLASSIC RADIATIONAL FOG EVENT WITH THE
SURFACE RIDGE OVERHEAD...LIGHT WINDS AND SMALL DEWPOINT DEPRESSIONS.
HOWEVER...FOG IS VERY PATCHY IN NATURE AND VISIBILITIES HAVE BEEN
RANGING FROM A FEW QUARTER MILE REPORTS TO P6SM. HOWEVER...WITH
DAWN APPROACHING AND TEMPERATURES GETTING CONSISTENTLY CLOSER TO
MINS...WE MAY HAVE A MORE CONSISTENT COVERAGE OF THE FOG HERE IN THE
NEXT FEW HOURS. FOR NOW...HAVE HELD OFF ON DOING A DENSE FOG
ADVISORY BUT WILL KEEP A CLOSE EYE ON CONDITIONS AND REEVALUATE AT
NEED.
THE STRATUS SHOULD FINALLY MOVE OFF TO THE EAST TODAY WITH WARM AIR
ADVECTION MOVING IN ALOFT...WARMER TEMPERATURES AND SOME MIXING OF
THE COLUMN TO HELP DISSIPATE THE STRATUS FROM WEST TO EAST.
ALSO...AS THE LOW LEVEL RIDGE SHIFTS EAST AND THIS SHOULD HELP TO
BODILY SHIFT THE STRATUS EAST...DESPITE THE WINDS BENEATH THE
INVERSION GOING FROM NEARLY CALM TO LIGHT SOUTHEAST...WHICH WOULD
BRING THE STRATUS BACK INTO THE AREA. THUS...HAVE GRADUALLY CLEARED
CLOUDS DURING THE MORNING HOURS AND WE SHOULD HAVE A SUNNY OR MOSTLY
SUNNY AFTERNOON. MIXING OF THE LOWEST LAYERS AND WARM AIR ADVECTION
SETTING IN ALOFT IN COMBINATION WITH SOME MORE SUNSHINE SHOULD HELP
BOOST TEMPERATURES TODAY. HAVE PUT HIGH TEMPERATURES IN THE 30S
NEARLY EVERYWHERE...BUT WOULD NOT BE SURPRISED TO SEE TEMPS IN THE
SOUTHWEST APPROACH 40 THIS AFTERNOON AS LONG AS THE STRATUS CLEARS
FAIRLY EARLY THIS MORNING. TONIGHT...WARM AIR ADVECTION GOING ON
ALOFT...LIGHT SOUTHEAST WINDS AND INCREASING HIGHER CLOUDS SHOULD
KEEP TEMPERATURES WARMER THAN THE CLOUD FREE AREAS THIS
MORNING...AND HAVE MIN TEMPS IN THE UPPER TEENS TO MID 20S.
.LE..
LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 341 AM CST THU MAR 7 2013
CHALLENGING WEEKEND SYSTEM REMAINS THE FOCUS OF THE EXTENDED
FORECAST. THE LAST COUPLE RUNS OF THE GFS AND ECMWF HAVE MIGRATED
TOWARD A WEAKER...LESS PHASED UPPER WAVE LIFTING OUT OF THE SW.
BOTH DEPICT THE INITIAL UPPER LOW OVER THE FOUR CORNERS REGION
SATURDAY MORNING LIFTING NORTHEAST...PHASING WITH A NORTHERN STREAM
TROUGH AND SWEEPING NORTHEAST INTO SE CANADA. A SECONDARY PIECE OF
ENERGY BREAKS OFF AND STAYS TO THE SOUTH...MOVING THROUGH THE MID MS
VALLEY AND THEN OHIO RIVER VALLEY MONDAY. THIS WOULD PRODUCE A
WEAKER...LESS ORGANIZED SURFACE LOW THAT LIFTS NORTHEAST ALONG
THE PASSING COLD FRONT LATE SATURDAY NIGHT AND EARLY SUNDAY.
THE NET RESULT IS A FASTER SYSTEM...NOW MORE LIKELY TO EXIT THE AREA
BY SUNDAY EVENING WITH POSSIBLY LOWER QPF TOTALS FROM RAIN AND LESS
POTENTIAL FOR MEASURABLE SNOW BEHIND THE COLD FRONT.
FRIDAY NIGHT...ELEVATED WARM ADVECTION AND MOISTURE RETURN ON A
40 KT 850 MB JET MAY SPREAD SHOWERS INTO ESPECIALLY THE WESTERN HALF
OF THE FORECAST AREA AFTER MIDNIGHT. THERE REMAINS A POTENTIAL THAT
SURFACE TEMPERATURES MAY INITIALLY BE NEAR OR BELOW FREEZING ACROSS
THE NORTH AND NORTHEAST AND WILL KEEP A MENTION OF FREEZING RAIN.
SATURDAY SHOULD SEE PRECIPITATION DUE TO THE WARM ADVECTION AND
INCREASINGLY DIFFLUENT FLOW ALOFT...BUT AT THIS TIME IT LOOKS TO BE
MORE OF A SHOWERY NATURE. THE BEST POTENTIAL FOR WIDESPREAD RAIN
SHOULD BE IN THE WEST CLOSER TO THE APPROACHING FRONT WHERE POPS ARE
GREATEST. OTHERWISE...TEMPERATURES AND DEWPOINTS SHOULD RISE WELL
INTO THE 40S WITH SOUTHEAST WINDS LIKELY STRONG ENOUGH TO KEEP
ADVECTION FOG AT BAY. WIDESPREAD RAIN WILL BE FOCUSED ON SATURDAY
NIGHT WITH THE PASSAGE OF THE UPPER LEVEL WAVE AND THEN SURFACE COLD
FRONT TOWARD MORNING. WIDESPREAD QPF AMOUNTS OF .5 TO 1 INCH STILL
LOOK REASONABLE...WITH POSSIBLE LOCALLY HIGHER AMOUNTS IF ANY
CONVECTION TAKES PLACE. LINGERING SNOW COVER MAY EFFECTIVELY CAPTURE
MUCH OF THIS RAIN...WHICH WOULD DELAY OR PROLONG THE RUNOFF...WHILE
AT THE SAME TIME COULD ALSO LEAD TO MINOR URBAN FLOODING DUE TO
CLOGGED DRAINAGE. ANOTHER CONCERN WILL BE THE POTENTIAL FOR
WIDESPREAD FOG DUE TO LIGHT WINDS AND LOW LEVEL CONVERGENCE ALONG
THE FRONT AND PASSING WEAK SURFACE WAVE. HAVE ADDED FOG WORDING TO
THE FORECAST...BUT WILL HOLD OFF ON MENTIONING HYDRO CONCERNS UNTIL
CONFIDENCE OF HEAVIER QPF INCREASES.
SUNDAY...THE COLD FRONT IS NOW SHOWN EAST OF THE AREA BY MIDDAY WITH
LITTLE UPPER LEVEL FORCING POST FRONTAL AS THE UPPER TROUGH SHIFTS
EAST BY EVENING. COLD ADVECTION MAY CHANGE RAIN TO SNOW...BUT AT
THIS TIME IT LOOKS LIKE MINIMAL ACCUMULATIONS WITH ANY PRECIPITATION
LIKELY ENDING BY EARLY EVENING. ADVERTISED FORECAST HIGHS...IN THE
40S TO AROUND 50...WOULD OCCUR EARLY IN THE DAY...AND IF THE CURRENT
TIMING HOLDS...THESE NUMBERS MAY BE A CATEGORY OR TWO TO MILD.
MONDAY THROUGH WED...SURFACE HIGH PRESSURE AND NW FLOW ALOFT SHOULD
PROVIDE CONTINUED BELOW NORMAL TEMPERATURES. OUTSIDE OF A CLIPPER
SYSTEM CURRENTLY SHOWN PASSING WELL TO THE NORTH AROUND
TUESDAY...THERE WILL BE LITTLE POTENTIAL FOR PRECIPITATION.
SHEETS
AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 546 AM CST THU MAR 7 2013
STRATUS AND FOG TO DOMINATE THE AVIATION FORECAST THIS MORNING.
KMLI AND KBRL STILL AFFECTED BY MVFR STRATUS WITH CIGS AROUND
1800FT. THIS STRATUS IS HOLDING STEADY BUT SHOULD GRADUALLY MOVE
EAST IN THE MORNING AND SHOULD CLEAR AND RETURN TO VFR BETWEEN
15Z- 18Z. KCID AND KDBQ ARE NOT UNDER THE STRATUS BUT HAVE
DEVELOPED FOG WITH HIGHLY VARIABLE VISIBILITIES AND VERTICAL
VISIBILITIES. CONDITIONS ARE LIFR AT TIMES...BUT THIS SHOULD
DISSIPATE BY 16Z. VERY LIGHT WINDS TO TURN SOUTHEAST BUT REMAIN
LESS THAN 8KTS THROUGH THE PERIOD. FOG IS POSSIBLE AGAIN
TONIGHT...AND HAVE PUT SOME MVFR FOG INTO TERMINALS AFTER
08Z...THOUGH CONFIDENCE IN TIMING OR LOCATION IS NOT VERY HIGH.
.LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1216 PM EST THU MAR 07 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1059 AM EST Wed Mar 5 2013
Morning satellite imagery shows widespread low clouds across the
forecast area this morning. Combination of inversion aloft along
with light winds will keep the low clouds socked in for much of the
day. Some very light drizzle and snow flurries will be possible in
areas throughout the day as well. With the expected cloud cover to
persist, have adjusted temperatures down several degrees to account
for the loss of solar insolation. Highs probably will only top out
in the lower 30s in the east with mid to upper 30s across the
central and west.
Updated forecast products are in production and will be available
shortly.
&&
.Short Term (Now - Friday)...
Issued at 305 AM EST Thu Mar 7 2013
Although a few flurries or instances of drizzle aren`t out of the
realm of possibilities this morning, believe most areas should be
dry through the short term period. Sfc high pressure and upper
level ridging will work into the area through Friday. The main
short term challenges will be the exit of low level stratus this
afternoon/evening and temperatures.
For today, think that the morning hours will remain cloudy. Latest
model runs keep pushing back the erosion of stratus across the area
which makes sense...thick stratus is stubborn to erode in most
cases. Thus, think that south central KY may see some sunshine by
mid afternoon, but southern Indiana and north central KY will stay
cloudy for much of the day. For the northern portions of the area,
clouds will likely erode sometime this evening from SW to NE.
Tonight and Friday should be mostly clear or only partly cloudy.
As for temperatures, think that low clouds will prohibit much of a
diurnal rise today except for maybe in south central KY where
stratus is expected to become more scattered in nature. Thus, have
gone below guidance for high temps over much of the area today. A
good temp gradient will likely set up along the edge of the stratus
deck which will be tough to nail down. Highs should range from the
upper 30s to mid 40s from NE to SW.
For tonight, think we`ll see good cooling with light northeasterly
winds and clear skies in place. Low temps should fall into the low
to mid 20s.
Friday will feature plenty of sunshine and temperatures warming into
the upper 40s and lower 50s.
.Long Term (Friday Night through Wednesday)...
Issued at 315 AM EST Thu Mar 7 2013
Friday Night - Saturday Night...
Upper level ridge axis will be directly overhead Friday night, with
surface high pressure anchored over the eastern Great Lakes. These
two features will slide east, albeit slowly due to downstream
blocking, through the majority of the weekend. This will set the
stage for a dry and much milder period of weather. Friday night lows
will be slightly below normal for this time of year due to good
radiational cooling conditions, however temperatures will quickly
recover on Saturday into the upper 50s and low 60s across the
region. Saturday Night will feature much milder lows as steady
southerly flow sets in between high to our east and the next
developing storm system to our west. Lows will only drop to the
40-45 degree range. One thing worth noting, is that models have sped
up with respect to first wave of warm advection rainfall around dawn
on Sunday. Will leave western fringes dry for now, but may
eventually have to introduce small chances of measurable rain very
late in the period Saturday night due to the isentropic lift regime
that will be in place.
Sunday - Tuesday...
By Sunday, upper level ridge axis will be along the Atlantic Coast
with split upper level flow across the western two-thirds of the
CONUS. Broad southwest flow aloft will develop over the region
between ridging to our east and troughing over the SW CONUS, with
elongated surface trough/boundary just to our west.
The trend has continued to be faster with precipitation arrival on
Sunday, however confidence is not all that high due to split upper
level flow and general inconsistency in model performance to this
point. Don`t want to totally buy into how fast models are with the
system yet due to the downstream blocking, and tendency for more
amplified/slower overall progression of systems. Nevertheless, have
introduced 30-40 percent chances of rain mainly across southern
Indiana for Sunday. Sunday will continue the warming trend as steady
southerly flow persists and temperatures jump into the low and mid
60s, however will stay away from the warmest guidance as increasing
cloud cover and perhaps some precipitation will keep temps down
slightly.
Periodic rain will be likely for Sunday night and Monday as a couple
of waves ride along a slowly eastward progressing boundary oriented
nearly parallel to the upper level flow. Could end up getting a
pretty decent amount of rainfall as the system will be slow and
PWATS up around 1.25" through the column overspread the region. Will
continue to leave thunder out as thermal profiles are moist
adiabatic at best, however will continue to monitor.
The frontal boundary looks to move through by Monday
afternoon/evening with precipitation beginning to taper off Monday
night. Will only keep lingering pops in the east on Tuesday. Still
keeping any snow mention out of the forecast as cold air does not
look to catch up to deep moisture in time, but this will be another
portion of the forecast that needs continued monitoring. Lows Monday
and Tuesday nights will be in the mid and upper 30s, with highs on
Tuesday and Wednesday in the upper 40s to around 50.
&&
.Aviation (18Z TAF Issuance)...
Issued at 1215 PM EST Thu Mar 7 2013
Main TAF issue through the period will be the lingering low-level
stratus deck across the region. Strong capping inversion aloft is
keeping the low-level moisture locked in place. While the latest
NAM and GFS runs are suggestive of the clouds scouring out this
afternoon, it seems more likely that it will be later tonight before
things clear out in earnest. Given that the RAP model seems to have
a pretty good handle on things, plan on leaving the MVFR cigs in the
forecast for this afternoon and a good part of the evening and into
the overnight period. It is very possible that we may not scour out
to VFR until Friday morning. However, we`ll continue to look at
future datasets and adjust the forecast as necessary. Winds will be
light across the region and out of the north and northwest. Winds
will gradually shift to the northeast tonight and remain light.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........MJ
Short Term.......AMS
Long Term........BJS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1235 PM EST THU MAR 7 2013
.SYNOPSIS...
ISSUED AT 328 AM EST THU MAR 7 2013
LAKE SHORE AREAS WILL SEE OCCASIONAL FLURRIES OR LIGHT SNOW
TODAY...OTHERWISE IT WILL BE PARTLY TO MOSTLY CLOUDY WITH
TEMPERATURES IN THE 30S. DRY WEATHER IS EXPECTED FOR FRIDAY AND
MUCH OF SATURDAY. TEMPERATURES WILL WARM TO AROUND 40 ON FRIDAY AND
INTO THE 40S FOR SATURDAY.
A RATHER UNSETTLED PERIOD IS EXPECTED LATE IN THE WEEKEND AND INTO
EARLY NEXT WEEK. RAIN IS EXPECTED BY LATE SATURDAY OR SATURDAY
NIGHT AND CONTINUING INTO SUNDAY. THE PRECIPITATION MAY CHANGE TO
SNOW...OR A MIX OF RAIN AND SNOW SUNDAY NIGHT THROUGH MONDAY
NIGHT...AS TEMPERATURES COOL FOR NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1046 AM EST THU MAR 7 2013
I DECREASED CLOUD COVER FOR THE REMAINDER OF THE DAY. MANY OF THE
CLOUDS THAT WERE AROUND THIS MORNING HAVE CONTINUED TO ERODE AND
EXIT TO EAST. CLEARING WILL CONTINUE FROM WEST TO EAST THIS
AFTERNOON AND THIS IS SHOWN BY THE NAM AND RAP MODEL SUGGESTIONS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
A SMALL AREA OF LAKE EFFECT SNOW SHOWERS/FLURRIES WAS CLIPPING
WESTERN VAN BUREN COUNTY THIS MORNING. EXPECT THIS MAY LINGER MUCH
OF TODAY AS COLD ADVECTION PEAKS AROUND MID DAY. THE FLOW REMAINS
330-350 SO ONLY THE LAKE SHORE WILL EXPERIENCE OCCASIONAL FLURRIES
OR LIGHT SNOW. IT COULD RESULT IN A LIGHT DUSTING IN SOME LOCALES.
INLAND AREAS SHOULD SEE A MIX OF CLOUDS AND SUN...WITH THE CLOUDS
MORE FREQUENT THAN SUN. SLIGHTLY COOLER THAN YESTERDAY WITH MOSTLY
LOW AND MID 30S FOR HIGHS.
UPPER RIDGING MOVES FOR THE END OF THE WORK WEEK. ALONG WITH THIS
WILL COME WARM ADVECTION. ANY LAKE SNOW SHOULD END BY THIS EVENING
ON THE HEELS OF THE WARM ADVECTION. SKIES SHOULD GRADUALLY CLEAR
LEADING TO A MOSTLY SUNNY FRIDAY WITH TEMPS APPROACHING 40.
CLOUDS SHOULD THICKEN THROUGH SATURDAY WITH WARM ADVECTION CLOUDS
AND AN INCREASING GULF MOISTURE FLOW. THE WARM FETCH WILL PUSH
TEMPS WELL INTO THE 40S. WE MAY SEE A FEW RAIN SHOWERS TOWARD
SATURDAY EVENING AS THE LOW LEVELS MOISTEN AHEAD OF A SYSTEM
DEVELOPING OVER THE CENTRAL PLAINS.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
SCATTERED TO NUMEROUS RAIN SHOWERS ARE EXPECTED SATURDAY NIGHT AND
SUNDAY AS A WARM AIR ADVECTION PATTERN IMPACTS THE REGION. 40 TO 50
KT SOUTHERLY LOW LEVEL JET IS PROGGED OUT AHEAD OF AN APPROACHING
FRONTAL BOUNDARY... WITH NARROW CORRIDOR OF PWATS AROUND ONE INCH
STREAMING NORTH. WILL NOT INCLUDE THUNDER AT THIS POINT... BUT WILL
HAVE TO WATCH FOR THAT POSSIBILITY. MODELS ARE STILL STRUGGLING WITH
TIMING/STRENGTH OF JET STREAK ENERGY EJECTING NORTHEAST FROM THE
FOUR CORNERS REGION... BUT IT DOES LIKE A STRONG SHORTWAVE WILL BE
MOVING INTO IOWA AROUND 12Z SUNDAY.
CURRENT MODEL SOLUTIONS IMPLY THAT THE SHORTWAVE MOVING NEWD FROM
THE CENTRAL PLAINS REGION ON SUNDAY WILL WEAKEN AND SHEAR OUT AS IT
COMES INTO MI AND GETS ABSORBED IN WITH AN APPROACHING NRN STREAM
TROUGH. THE SFC FRONTAL BOUNDARY ALSO WEAKENS BUT DOES SLIP THROUGH
THE ENTIRE CWFA BY 12Z MONDAY. MODELS HAVE BEEN VERY INCONSISTENT IN
REGARDS TO WHAT HAPPENS AFTER THAT... BUT CONTINUE TO SUGGEST THE
POSSIBILITY OF ANOTHER WAVE MOVING MOVING NORTHEAST ALONG THE SFC
FRONT EARLY NEXT WEEK. PRECIP TYPE REMAINS PROBLEMATIC... SINCE
IF THE FRONT GETS HUNG UP THEN THE LOW LEVEL COLD AIR MAY HAVE A
TOUGH TIME FILTERING INTO THE REGION FROM THE NORTH.
DESPITE THE MODEL INCONSISTENCIES FOR EARLY NEXT WEEK... ALL
SOLUTIONS SEEM TO EVENTUALLY CONVERGE ON A RATHER CHILLY PATTERN BY
MID WEEK WITH TROUGHING AND COLD AIR ALOFT. THIS WOULD LEAD TO
SCATTERED SNOW OR MIXED RAIN AND SNOW SHOWERS AND HIGHS IN THE 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM EST THU MAR 7 2013
CONFIDENCE IS HIGH THAT VFR CONDITIONS WILL PREVAIL THROUGH THIS
EVENING. CEILINGS IN THE 3000-4000 FT AGL RANGE SHOULD SLOWLY RISE
THIS AFTERNOON AND MAY EVEN SLOWLY DISSIPATE FROM NORTHWEST TO
SOUTHEAST DURING THIS TIME. THE EASTERNMOST TERMINALS (KLAN AND
KJXN) HAVE THE BEST CHANCE OF HOLDING ON TO CEILINGS FOR MOST OF THE
DAY.
ALTHOUGH NOT ADVERTISED SPECIFICALLY IN THE TAFS...A LOSS OF CEILINGS
OVERNIGHT COMBINED WITH LIGHT WINDS WILL MAKE PATCHY FOG POSSIBLE.
IF FOG WERE TO OCCUR AT THE TERMINALS...IT WOULD MOST LIKELY START
AFTER 06Z AND HAVE A GOOD CHANCE OF DROPPING BELOW IFR VISIBILITY
THRESHOLDS OF 3 MILES. THIS WILL BE THE MAIN THING TO WATCH
THROUGH THE NEXT SCHEDULED TAF UPDATE.
&&
.MARINE...
ISSUED AT 328 AM EST THU MAR 7 2013
RATHER LIGHT NW WINDS TODAY WILL KEEP WAVES ON THE LOWER SIDE.
WINDS REMAIN LIGHT THROUGH MUCH OF THE SHORT TERM. HOWEVER WINDS
AND WAVES SHOULD INCREASE BY SATURDAY AFTERNOON AS THE NEXT SYSTEM
APPROACHES.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST THU MAR 7 2013
A GRADUAL THAW WILL CONTINUE WITH ABOVE FREEZING DAYTIME TEMPS AND
DROPPING BELOW FREEZING AT NIGHT. WARMER CONDITIONS ARRIVE OVER THE
WEEKEND ALONG WITH SOME RAIN. THIS COMBINATION WILL BE MONITORED
FOR POSSIBLE HYDRO IMPACTS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...JAM WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...TJT
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1150 AM EST THU MAR 7 2013
.SYNOPSIS...
STRONG LOW PRESSURE OFF THE MIDATLANTIC COAST WILL MOVE FURTHER OUT
TO SEA TODAY. DRY HIGH PRESSURE WILL BUILD INTO THE REGION THIS
AFTERNOON... AND LINGER THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1022 AM THURSDAY...
REST OF TODAY: A MUCH QUIETER DAY THAN THE LAST FEW... ALTHOUGH
WE`LL STILL SEE SOME CLOUDINESS (ESPECIALLY FAR WEST AND IN THE
NORTHEAST) ALONG WITH BELOW-NORMAL TEMPS AND GUSTY WINDS. THE
POWERFUL STORM SYSTEM IS CENTERED WELL OFF THE MIDATLANTIC COAST
ACCORDING TO THE LATEST SURFACE ANALYSIS... ALTHOUGH ITS CIRCULATION
WILL CONTINUE TO PULL LOW LEVEL MOISTURE (BENEATH THE SUBSIDENCE
INVERSION ALOFT) INTO NORTH CENTRAL AND NORTHEAST NC. 925-850 MB
PROGS FROM THE 12KM NAM AS WELL AS THE HRRR INDICATE STRATOCU
SPREADING TO THE SSE INTO THIS AREA TODAY... AND MORNING SOUNDINGS
AND TRAJECTORIES ALONG WITH SATELLITE IMAGERY SUPPORT A PERIOD OF
PARTLY SUNNY TO MOSTLY CLOUDY SKIES OVER THE COASTAL PLAIN AND
NORTHEAST PIEDMONT THROUGH THE REST OF THE DAY. OVER THE FAR WESTERN
PIEDMONT... OROGRAPHICALLY ENHANCED CIRRUS IS LIKELY TO PERSIST FOR
A FEW MORE HOURS GIVEN THAT OBSERVED AND FORECAST SOUNDINGS SHOW A
FAVORABLE WIND PROFILE. THE THICKER CLOUDS IN THE NORTHEAST WILL
IMPACT TEMPS... AS SUGGESTED BY THE LATEST HRRR OUTPUT... SUGGESTING
HIGHS THERE IN THE LOWER 50S... WHEREAS AREAS FROM THE TRIANGLE AND
TRIAD TO THE SOUTH AND SW SHOULD SEE HIGHS IN THE MID-UPPER 50S. THE
MIXED LAYER NOTED IN FORECAST SOUNDINGS SUPPORTS GUSTS AROUND 20-25
MPH IN THE FAR NORTHEAST (NEAREST THE TIGHTER MSLP GRADIENT) BUT
JUST 15-20 ELSEWHERE... BEFORE THE DEPARTURE OF THE STORM SYSTEM
RESULTS IN A SLOW DIMINISHING OF WINDS TOWARD NIGHTFALL. -GIH
TONIGHT...STRONG VORT MAX IN THE NW FLOW ALOFT WILL DROP SEWD FROM
THE NORTHERN GREAT LAKES INTO NORTHERN MID ATLANTIC TONIGHT THEN OFF
THE VIRGINIA CAPE BY EARLY FRI. THIS SYSTEM WILL BE MOISTURE STARVED
SO EXPECT LITTLE IN THE MANNER OF CLOUDS. HOWEVER...THIS SYSTEM WILL
MAINTAIN A FAIRLY TIGHT PRESSURE GRADIENT SO WINDS WILL MAINTAIN
5-9KTS OVERNIGHT. THIS MIXING WILL AID TO KEEP TEMPS UP A BIT. IF
SFC WINDS DECOUPLE...MORE LIKELY IN THE WESTERN PIEDMONT...COULD SEE
TEMPS TUMBLE 4-5 DEGREES COLDER THAN FORECAST. MIN TEMPS UPPER 20S
WEST TO LOWER 30S COASTAL PLAIN. -WSS
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 300 AM THURSDAY...
FRIDAY AND FRIDAY NIGHT...AS STRONG VORT EXITS OFF THE MID ATLANTIC
COAST...LOW LEVEL FLOW WILL BECOME MORE N-NE. SOME MODELS
(ESPECIALLY NAM) DEPICT MORE OF A FETCH OFF THE ATLANTIC WHILE THE
GFS AND ECMWF MAINTAIN A NLY FLOW (MAINLY OVER LAND). CONSIDERING
THE AMOUNT OF MOISTURE ON THE BACK SIDE OF THE DEEP LOW...NAM MAY BE
ONTO SOMETHING. THUS HAVE INCREASED CLOUD COVERAGE IN THE EAST LATE
FRI INTO FRIDAY NIGHT. WITH A FEW MORE CLOUDS EXPECTED NE VERSUS
SW...SHOULD SEE COOLER MAX TEMPS NE AND WARMER SW. MAX TEMPS NEAR 50
NORTHERN COASTAL PLAIN TO MID-UPPER 50S SW. MIN TEMPS FRIDAY NIGHT
HIGHLY DEPENDENT ON EXTENT OF CLOUD COVERAGE. USED A BLEND OF MOS
GUIDANCE FOR MIN TEMPS. HOWEVER IF CLOUDS DO MATERIALIZE...MIN TEMPS
WILL NEED TO BE ADJUSTED UP A FEW DEGREES. CONVERSELY...IF CLOUDS DO
NOT FORM AND SFC WINDS DECOUPLE...MIN TEMPS WILL NEED TO BE ADJUSTED
DOWN 4-5 DEGREES.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 250 AM THURSDAY...
THIS WEEKEND: BENEATH A BUILDING AND SLOWLY PROGRESSIVE RIDGE
ALOFT...1030 MB SURFACE HIGH PRESSURE WILL SPAN THE LENGTH OF THE
EAST COAST. THE RIDGING WILL PROVIDE FOR GENERALLY CLEAR AND
MODERATING CONDITIONS FOR CENTRAL NC...WITH THE ONLY APPRECIABLE
CLOUD COVER...ASIDE FROM CIRRUS...LIKELY TO HOLD WEST OF THE YADKIN
IN RETURN LOW LEVEL FLOW SUN NIGHT-MON MORNING. STEADILY RISING
THICKNESSES SUGGEST HIGHS AROUND 60 DEGREES SAT...AND IN THE
LOWER-MIDDLE 60S SUN. BELOW GUIDANCE LOWS IN THE 29 TO 34 DEGREE
RANGE WITH EXCELLENT RADIATIONAL SAT NIGHT...AND ABOUT 10 DEGREES
MILDER SUN NIGHT.
MONDAY THROUGH WEDNESDAY: THE DEEP LAYER RIDGING WILL CONTINUE
EASTWARD IN THE AFOREMENTIONED SLOWLY PROGRESSIVE FLOW...IN ADVANCE
OF A COMPLEX TROUGH ALOFT OVER AND OFFSHORE THE PAC NW COAST THIS
MORNING. MEDIUM RANGE GUIDANCE IS IN REASONABLY GOOD AGREEMENT
REGARDING THE PROGRESSION OF THIS TROUGH AND ACCOMPANYING WET LOW
LEVEL FRONTAL ZONE ACROSS CENTRAL NC MON NIGHT-TUE...WITH A
PRECEDING RESIDUAL CAPPING INVERSION LIKELY TO HOLD THROUGH THE DAY
MON. INHERENT UNCERTAINTY AT THIS TIME RANGE FAVORS HOLDING POP IN
THE 50-60 PERCENT RANGE...BUT CATEGORICAL PROBABILITIES WILL
ULTIMATELY BE WARRANTED WITH TIME GIVEN THE EXPECTED WIDE-OPEN AND
STRONG GULF INFLOW INTO THE FRONTAL ZONE. POST-FRONTAL COOLER AND
DRIER CONDITIONS WILL PREVAIL FOR MID-LATE WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 1150 AM THURSDAY...
HIGH CONFIDENCE IN CONTINUED VFR CONDITIONS THROUGH FRIDAY. THE LOW
PRESSURE SYSTEM FROM THE LAST FEW DAYS WILL CONTINUE A STEADY
EASTWARD DRIFT OUT TO SEA TODAY... HOWEVER THE CIRCULATION WILL
STILL INFLUENCE US AS WE WILL MAINTAIN A MAINLY NORTHERLY BREEZE
THIS AFTERNOON -- STRONGER (10-15 KTS GUSTING TO 20-25 KTS) AT RWI
TAPERING WEAKER (AROUND 10 KTS WITH INFREQUENT GUSTS AROUND 15 KTS)
AT INT/GSO. SURFACE HIGH PRESSURE CENTERED OVER ONTARIO AND THE
UPPER GREAT LAKES WILL EXTEND WELL SOUTHWARD... BUILDING SLOWLY
EASTWARD OVER EASTERN NOAM OVER THE NEXT 36 HOURS. ANY CLOUDS TODAY
WILL BE BASED ABOVE 3 THOUSAND FT AGL... MOST EXTENSIVE AT
RWI/RDU/FAY. SKIES WILL BECOME UNLIMITED THIS EVENING AND REMAIN SO
WELL INTO FRIDAY WITH JUST LIGHT (10 KTS OR LOWER) WINDS FROM THE
NORTH.
LOOKING BEYOND FRIDAY AFTERNOON... MID-LEVEL LOW PRESSURE OVER LAKE
SUPERIOR THIS MORNING WILL DROP SOUTHEASTWARD BRUSHING NORTHEAST NC
LATE FRIDAY INTO FRIDAY NIGHT... AND THIS MAY BRING A PERIOD OF
SCT-BKN CLOUDS AT 2500-3000 FT AGL LATE FRIDAY NIGHT AT RDU/RWI.
OTHERWISE VFR CONDITIONS WILL HOLD INTO LATE SUNDAY MORNING THROUGH
MONDAY MORNING... WHEN MOIST LOW LEVEL FLOW WILL BRING A RISK OF IFR
CONDITIONS. BREEZY WINDS FROM THE SOUTHWEST AND MVFR CIGS/VSBYS WITH
SHOWERS ARE POSSIBLE LATE MONDAY INTO TUESDAY AS FRONTAL SYSTEM
CROSSES THE REGION. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...MWS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
300 PM EST THU MAR 7 2013
.SYNOPSIS...
LOW PRESSURE OFF THE EAST COAST DRIFTS SLOWLY AWAY THROUGH
FRIDAY...ALLOWING HIGH PRESSURE TO BUILD IN THIS WEEKEND. A COLD
FRONT AND WAVE OF LOW PRESSURE MOVE THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
STILL COULD SEE A PEAK OF SUN OR TWO INTO THE KANAWHA VALLEY THIS
AFTERNOON...BUT CANNOT ELIMINATING THE LOW LEVEL MOISTURE IN
PLACE DOWNWIND OF THE GREAT LAKES. RUC HAS THE STRATUS DECK THROUGH
05Z TONIGHT...AND OTHER MODELS DRYING OUT THE WESTERN LOWLANDS AFTER
06Z. THE SUN MAKES AN APPEARANCE FRIDAY WITH HIGH PRESSURE DRIFTING
ACROSS THE SOUTHERN GREAT LAKES AND DRYING LOW LEVELS. NAM AT 925MB
STILL HAS NORTHERLY FLOW AND SATURATION IN A LINGERING THERMAL
TROUGH...SO KEPT THE CLOUDS IN PLACE OVER THE TYGART AND GREENBRIER
VALLEYS. WILL SEE A SLOW IMPROVEMENT TO THE 850MB TEMPERATURES...BUT
WILL NOT QUITE GET INTO THE EFFICIENT WARM UP WITH A NORTHERLY
COMPONENT TO THE WIND AT THE SURFACE AN LOW LEVELS THROUGH 00Z
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
HIGH PRESSURE IS IN CONTROL AT THE SURFACE FOR THE FIRST HALF OF THE
WEEKEND...WITH A RIDGE BUILDING IN ALOFT. THIS WILL SPELL ABOVE
NORMAL AFTERNOON HIGHS ACROSS MUCH OF THE FORECAST AREA. HIGHS MAY
BE TEMPERED A BIT BY LINGERING SNOW COVER IN THE NORTHERN MOUNTAINS
OF WEST VIRGINIA SO STAY A BIT BELOW GUIDANCE THERE. MODEL TIMING A
LITTLE DIFFERENT ON WHEN THE LEADING PRECIP AHEAD OF THE NEXT SYSTEM
MAY ENTER OUR WESTERN ZONES. ONLY MADE LITTLE CHANGES FROM PREVIOUS
POP FORECAST...WITH SLIGHT CHANCE POPS ENTERING FROM THE WEST
SATURDAY AFTERNOON. DESPITE INCREASING HIGH CLOUDS...SUNDAY SHOULD
BE THE WARMER DAY OF THE WEEKEND...WITH LOW TO MID 60S PRETTY
WIDESPREAD ACROSS THE LOWER ELEVATIONS...AND UPPER 40S TO 50S IN THE
MOUNTAINS AS SNOW PACK CONTINUES TO MELT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MOISTURE FROM THE LEADING EDGE OF THE NEXT FRONTAL SYSTEM WILL BEGIN
TO SPREAD OVER THE WESTERN PORTIONS OF THE FORECAST AREA LATE SUNDAY
NIGHT AS THE WEEKENDS UPPER LEVEL RIDGE SLIDES EAST INTO THE
ATLANTIC. RAINFALL WILL BECOME MORE WIDESPREAD THROUGH THE DAY
MONDAY AS A FRONTAL SYSTEM WITH A GOOD SOUTHERLY FETCH SHIFTS EAST.
WITH TEMPERATURES REMAINING WARM DURING THIS TIME PERIOD WILL NEED
TO WATCH THE FRONT CLOSELY FOR HYDRO CONCERNS. SO FAR MODELS ARE
SHIFTING IT EAST QUICKLY ENOUGH TO KEEP PRECIPITATION AMOUNTS IN THE
INCH RANGE BUT IF WAVES END UP FORMING ALONG THE FRONTAL BOUNDARY
AND IT STALLS...THE NORTH TO SOUTH ORIENTATION OF THE SYSTEM WOULD
BE FAVORABLE FOR PICKING A GOOD BIT MORE RAIN. AGAIN AT MOMENT IT
DOES NOT LOOK LIKE THE FRONT WILL STALL BUT RATHER JUST SOMETHING TO
WATCH. COOLER AIR WILL SWING DOWN BEHIND THE FRONTAL MIDWEEK BUT
LOOKS FAR ENOUGH BEHIND THAT MOST OF THE LINGERING POST FRONTAL
SHOWERS WILL BE OVER WITH BY THEN.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
LOW LEVEL MOISTURE WILL BE PERSISTENT INTO TONIGHT...AND CONTINUE
TO HANG ON IN THE MOUNTAINS THROUGH THE TAF PERIOD. THIS WILL LEAD
TO PRIMARILY MVFR CEILINGS AREA WIDE...WITH BRIEF VFR POSSIBLE
THIS AFTERNOON FOR THE LOWLAND TERMINALS. CEILINGS TO LOWER A
LITTLE BIT TONIGHT...AND WILL FLIRT WITH IFR ONCE AGAIN. BKW TO
CONTINUE WITH LIFR CONDITIONS THROUGH THIS EVENING.
NORTHWEST FLOW TO 10KTS...WITH THE OCCASIONAL GUST TO
15KTS...LIKELY THROUGH FRIDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE...MEDIUM TO HIGH.
ALTERNATE SCENARIOS: MAY NEED MORE IFR TONIGHT FROM LOWER
CEILINGS. TIME OF LOW LEVEL MOISTURE EXIT AND CLOUD BREAK UP COULD
VARY INTO TONIGHT AND FRIDAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H H H H M M M H M L L
HTS CONSISTENCY H H H H M M M M M H M M
BKW CONSISTENCY L L H H M H M M M L L L
EKN CONSISTENCY L L L L L L L L L L L L
PKB CONSISTENCY H H H H H H H H M M H H
CKB CONSISTENCY H H H H M M M M M H H L
AFTER 18Z FRIDAY...
NO WIDESPREAD IFR EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...MZ/26/JR
NEAR TERM...26
SHORT TERM...MZ
LONG TERM...JR
AVIATION...26
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1042 AM MST THU MAR 7 2013
.UPDATE...
ISSUED AT 830 AM MST THU MAR 7 2013
15Z SURFACE ANALYSIS HAD WEAK LOW OVER NORTHEAST WY WITH GENTLE
COOL FRONT/TROUGH FROM CENTRAL MT INTO SOUTHWEST SD. MID/HIGH
CLOUDS STREAMING OVER CWA ON 90KT UPPER LEVEL JET...BUT THEY ARE
PARTIALLY TRANSPARENT. 12Z RAP MESHES WELL WITH CURRENT TRENDS.
WILL TWEAK TEMPERATURES WEST OF THE FRONT A COUPLE OF DEGREES UP
BASED ON 12Z RAP/KUNR SOUNDING...AND EAST OF THE FRONT A TAD LOWER
GIVEN UPSTREAM SURFACE TRAJECTORIES. REST OF FORECAST IN GOOD
SHAPE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 305 AM MST THU MAR 7 2013
WESTERN CONUS TROUGHING CONTINUES...SUPPORTING FAST
DISTURBED OVER THE LOCAL REGION. ASSOCIATED ADVECTING IMPULSE
CONTINUES TO PROPAGATE ENE ACROSS THE NORTHERN PLAINS...WITH AN
ASSOCIATED LL TROUGH REFLECTION. THIS IMPULSE WILL CONTINUE EAST
TODAY...SUPPORTING WEAK CAA IN IT/S WAKE. FLOW WILL QUICKLY RESPOND
TO THE NEXT ADVANCING SHORTWAVE TOUGH AS THE MAIN WESTERN CONUS
LONG WAVE TROUGH CONTINUES TO DIG SOUTH INTO THE SW CONUS. WAA WILL
AGAIN SPREAD OVER THE REGION FRIDAY AHEAD OF THE NEXT ADVANCING
DISTURBANCE...WITH LL FLOW RESPONDING TO ONGOING PRESSURE FALLS.
WEAK DEFORMATION ZONE WILL DEVELOP OVER PORTIONS OF NE WY AND
MT...AND EAST INTO NORTH DAKOTA....POSSIBLY SUPPORTING SOME LIGHT
PRECIP ACTIVITY LATE FRIDAY MORNING INTO FRIDAY AFTERNOON THERE.
LATEST GUIDANCE CONTINUES TO TREND THIS AREA OF LIFT NW...WITH ONLY
LOW TO MID RANGE CHANCE POPS RETAINED OVER THE NW FA.
OTHERWISE...ATTENTION TURNS TOWARD INCREASING LARGE SCALE ASCENT
WITH THE AFOREMENTIONED LEAD SHORTWAVE TROUGH. INCREASING LL
MOISTURE PER SE LL FLOW WILL SUPPORT SUFFICIENT LL MOISTURE FLUX FOR
RAIN/SNOW/WITH THE POTENTIAL FOR FREEZING RAIN REMAINING OVER
SCENTRAL SD INTO CENTRAL SD...GIVEN A STRONG ELEVATED WARM TONGUE
ADVANCING NW AHEAD OF THIS WAVE. MEANWHILE...AN EXPECTED NORTHERN
STREAM TROUGH WILL QUICKLY ADVECT INTO THE NORTHERN PLAINS LATER
FRIDAY NIGHT...SUPPORTING INCREASING LL CAA AND INDUCED LL PRESSURE
FALLS. THIS WAVE AND ASSOCIATED COLD FRONT WILL INTRODUCE ENOUGH
COLD AIR TO END ALL MIXED PRECIP CHANCES SAT MORNING...WITH SNOW
BEING THE DOMINANT PRECIP TYPE ALL PLACES AS THE MAIN SW CONUS UPPER
TROUGH BEGINS TO EJECT TOWARD THE REGION.
FORECAST MODELS ARE STILL WAVERING ON THE EXACT DETAILS PER THIS
EVOLUTION...WITH STILL MANY DETAILS TO BE WORKED OUT.
HOWEVER...CONFIDENCE HAS INCREASED THAT THERE WILL BE A PERIOD OF
MIXED PRECIP IN SCENTRAL SD FRIDAY NIGHT. STRONG WARM NOSE /2-3C/ IN
A THETA-E ADV REGIME WITH INCREASING LSA WILL BE MORE THAN AMPLE
TO SUPPORT PRECIP DEVELOPMENT. FORECAST MODELS SUGGEST UP TO A
QUARTER INCH QPF IN FAR SCENTRAL SD...MAINLY RAIN AT FIRST WITH A
PERIOD OF ICING LIKELY LATER /WHICH IS IN LINE WITH CURRENT SREF
PROGS/. ATTM IT DOES NOT APPEAR TO THAT SIG ICING IS EXPECTED
GIVEN A RATHER WARM BL THROUGH FRI NIGHT. HOWEVER...SOME SOLUTIONS
SUGGEST UP TO A TENTH OF INCH OF ICE ACCUMS IS POSSIBLE ESP AROUND
THE WINNER AREA. THIS WILL NEED TO BE WATCHED.
SMALL ADJUSTMENT MADE TO HIGH TEMPS...WHICH WILL BE TRICKY TODAY
GIVEN THE ADVANCING COLD FRONT AND ASSOCIATED CAA TIMING. STILL
EXPECT 50S AND SOME LOWER 60S WILL BE POSSIBLE IN SW SD...WITH TEMPS
ONLY REACHING THE 40S OVER NW SD AND NE WY. COOLER TEMPS EXPECTED
FRI.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 305 AM MST THU MAR 7 2013
LARGE UPPER LEVEL TROF WILL CROSS THE NORTHERN PLAINS THIS WEEKEND
WITH A RIDGE BUILDING IN FOR EARLY NEXT WEEK. POTENT SYSTEM WITHIN
THE TROF WILL CROSS THE CENTRAL PLAINS ON SATURDAY AND SUNDAY...WITH
THE NORTHERN EDGE OF THE SYSTEM BRINGING ACCUMULATING SNOWS TO
SOUTHERN PORTIONS OF THE FORECAST AREA.
LATEST MODEL RUNS CONTINUE TO SHOW UPPER LOW SWINGING THROUGH THE
FOUR CORNERS AREA VERY EARLY SATURDAY MORNING...AND TRACKING
EAST-NORTHEASTWARD THROUGH THE WEEKEND. MID LEVEL LOW DEVELOPS
ACROSS EASTERN COLORADO BY MIDDAY SATURDAY AS NORTHERN EDGE OF
PRECIP SHIELD SHIFTS NORTH INTO THE AREA. AMPLE MOISTURE AND
NORTHERLY BOUNDARY LAYER FLOW WILL ALSO BRING UPSLOPE SNOW TO THE
NORTHERN BLACK HILLS AREA SATURDAY AND SATURDAY EVENING. SYSTEM
QUICKLY SHIFTS EAST SATURDAY NIGHT...WITH SNOW TAPERING OFF BY EARLY
SUNDAY MORNING.
THE BEST CHANCES FOR SIGNIFICANT PCPN AMOUNTS WILL BE ACROSS FAR
SOUTHERN SD...ESPECIALLY SOUTH CENTRAL SD...AND ACROSS THE NORTHERN
BLACK HILLS. UP TO 6 INCHES OF SNOWFALL WILL BE POSSIBLE IN THESE
AREAS.
BEYOND THAT...TEMPERATURES WILL GRADUALLY WARM INTO EARLY NEXT WEEK
AS RIDGE BUILDS OVER THE WESTERN CONUS. MOSTLY DRY WEATHER IS
EXPECTED ACROSS THE AREA...BUT WILL KEEP SOME LOW CHANCES FOR RAIN
AND SNOW SHOWERS FOR MONDAY AFTERNOON INTO TUESDAY ACROSS PORTIONS
OF NORTHEASTERN WY AND INTO THE BLACK HILLS AS WEAK UPPER LEVEL
ENERGY PASSES OVER THE RIDGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1041 AM MST THU MAR 7 2013
VFR CONDITIONS ARE GENERALLY EXPECTED THROUGH FRIDAY MORNING. THERE
IS A CHANCE FOR SNOW SHOWERS LATE TONIGHT AND FRIDAY MORNING ACROSS
FAR NORTHEASTERN WY INTO FAR NORTHWESTERN SD...WITH LOCAL MVFR
CONDITIONS EXPECTED.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...15
AVIATION...26
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1152 AM CST THU MAR 7 2013
.UPDATE...FOR 18Z TAFS.
&&
.AVIATION...
MVFR STRATUS DECK CONTINUES TO LINGER ACROSS THE FORECAST AREA.
CLEARING SHOWING UP ON VISIBILE SATELLITE IN SOUTHERN COUNTIES.
LOOK FOR CLEARING SKIES TO CONTINUE THROUGH 00Z. WITH LOW LEVEL
MOISTURE NOT MIXING OUT LOOK FOR SCT CU AT ALL TERMINALS THIS
AFTERNOON. LATE TONIGHT MVFR CONDITIONS WILL REAPPEAR FOR BNA AND
CKV AROUND 06Z. MVFR TO IFR CONDITIONS WILL TAKE PLACE AROUND CSV.
72/MD
&&
.PREV DISCUSSION... /ISSUED 1124 AM CST THU MAR 7 2013/
UPDATE...
LOW LEVEL MOISTURE IS PREVENTING TEMPERATURES FROM RISING THIS
MORNING AS PREVIOUSLY FORECAST. NEWEST RUC AND HRRR INDICATE THIS
CLOUD COVER SHOULD ERODE OVER THE NEXT FEW HOURS AND TEMPERATURES
WILL BEGIN TO RISE MORE RAPIDLY AT THAT POINT. HAVE LOWERED HIGHS
A FEW DEGREES BASED OFF THIS SKY TREND AND EDITED SKY GRIDS TO
REFLECT THE LATEST RUC DEPICTION.
PREV DISCUSSION... /ISSUED 526 AM CST THU MAR 7 2013/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
LOW DECK REMAINS ACROSS MUCH OF MID STATE EXCEPT FOR SOUTHWEST
CORNER. SHORT RANGE MODELS BEGIN ERODING LOW DECK FROM SOUTHWEST
AFTER 12Z. I HAVE CLARKSVILLE SCATTERED AT 25 HNDRD BY 15Z WITH
NASHVILLE GOING SCATTERED AT SAME LEVEL AROUND 16Z. NOT REAL
OPTIMISTIC ABOUT CROSSVILLE SCATTERING OUT DURING THE DAY BUT
SINCE MOIST LAYER IS QUITE THIN WOULD THINK IT WOULD MIX OUT
DURING THE DAY AT SOME POINT. I WENT WITH LOW DECK SCATTERING OUT
AROUND 20Z AT CROSSVILLE.
BOYD
PREV DISCUSSION... /ISSUED 211 AM CST THU MAR 7 2013/
DISCUSSION...SURFACE HIGH PRESSURE REMAINS SITUATED WEST OF
MIDDLE TENNESSEE WITH STUBBORN LOW CLOUDS STILL COVERING MOST OF
THE MID STATE. EVENING SOUNDING FROM OHX SHOWS THE CLOUD DECK ONLY
AROUND 1400 FT THICK, SO MORNING SUN SHOULD PROVIDE ENOUGH HEAT TO
QUICKLY ERODE CLOUD COVER AND FINALLY SCATTER US OUT. AFTERWARDS,
LOOK FOR SEVERAL DAYS OF MILD, QUIET WEATHER, WITH SIGNIFICANTLY
WARMER TEMPERATURES IN STORE THIS WEEKEND. SURFACE RIDGE WILL
LIKELY SLIDE EAST OF MIDDLE TENNESSEE FRIDAY OR FRIDAY NIGHT, WITH
A SW FLOW DEVELOPING ALOFT. NEXT ACTIVE WEATHER SYSTEM WILL MOVE
IN SUNDAY NIGHT, WITH THUNDERSTORMS ON MONDAY, ALTHOUGH MIDDLE
TENNESSEE IS NOWHERE NEAR ANY SEVERE WEATHER RISK AREA THROUGH DAY
8.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
72
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1124 AM CST THU MAR 7 2013
.UPDATE...
LOW LEVEL MOISTURE IS PREVENTING TEMPERATURES FROM RISING THIS
MORNING AS PREVIOUSLY FORECAST. NEWEST RUC AND HRRR INDICATE THIS
CLOUD COVER SHOULD ERODE OVER THE NEXT FEW HOURS AND TEMPERATURES
WILL BEGIN TO RISE MORE RAPIDLY AT THAT POINT. HAVE LOWERED HIGHS
A FEW DEGREES BASED OFF THIS SKY TREND AND EDITED SKY GRIDS TO
REFLECT THE LATEST RUC DEPICTION.
&&
.PREV DISCUSSION... /ISSUED 526 AM CST THU MAR 7 2013/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
LOW DECK REMAINS ACROSS MUCH OF MID STATE EXCEPT FOR SOUTHWEST
CORNER. SHORT RANGE MODELS BEGIN ERODING LOW DECK FROM SOUTHWEST
AFTER 12Z. I HAVE CLARKSVILLE SCATTERED AT 25 HNDRD BY 15Z WITH
NASHVILLE GOING SCATTERED AT SAME LEVEL AROUND 16Z. NOT REAL
OPTIMISTIC ABOUT CROSSVILLE SCATTERING OUT DURING THE DAY BUT
SINCE MOIST LAYER IS QUITE THIN WOULD THINK IT WOULD MIX OUT
DURING THE DAY AT SOME POINT. I WENT WITH LOW DECK SCATTERING OUT
AROUND 20Z AT CROSSVILLE.
BOYD
PREV DISCUSSION... /ISSUED 211 AM CST THU MAR 7 2013/
DISCUSSION...SURFACE HIGH PRESSURE REMAINS SITUATED WEST OF
MIDDLE TENNESSEE WITH STUBBORN LOW CLOUDS STILL COVERING MOST OF
THE MID STATE. EVENING SOUNDING FROM OHX SHOWS THE CLOUD DECK ONLY
AROUND 1400 FT THICK, SO MORNING SUN SHOULD PROVIDE ENOUGH HEAT TO
QUICKLY ERODE CLOUD COVER AND FINALLY SCATTER US OUT. AFTERWARDS,
LOOK FOR SEVERAL DAYS OF MILD, QUIET WEATHER, WITH SIGNIFICANTLY
WARMER TEMPERATURES IN STORE THIS WEEKEND. SURFACE RIDGE WILL
LIKELY SLIDE EAST OF MIDDLE TENNESSEE FRIDAY OR FRIDAY NIGHT, WITH
A SW FLOW DEVELOPING ALOFT. NEXT ACTIVE WEATHER SYSTEM WILL MOVE
IN SUNDAY NIGHT, WITH THUNDERSTORMS ON MONDAY, ALTHOUGH MIDDLE
TENNESSEE IS NOWHERE NEAR ANY SEVERE WEATHER RISK AREA THROUGH DAY
8.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TB12
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SYNOPSIS...
ISSUED AT 240 PM CST THU MAR 7 2013
SEASONABLE TEMPERATURES...WITH THE NEXT CHANCE FOR
SIGNIFICANT PRECIPITATION COMING DURING THE WEEKEND.
AMPLIFIED SPLIT FLOW REGIME IN PLACE ACRS NOAM. THAT WL PERSIST
THROUGH THE WEEKND AS STG SRN STREAM TROF MIGRATES EWD ACRS THE
COUNTRY. THE TREND NEXT WK WL BE FOR THE FLOW TO BECOME MORE
CONSOLIDATED AND LOSE AMPLITUDE.
THE PATTERN WILL NOT SUPPORT ANY SIG COLD INTRUSIONS INTO THE
AREA...SO TEMPS SHOULD BE NR OR A LITTLE ABV NORMAL FOR THE MOST
PART. MAIN PCPN EVENT WL BE WITH THE CYCLONE CROSSING THE RGN THIS
WEEKEND...WITH AMNTS PROBABLY ENDING UP NR OR A LITTLE ABV NORMAL.
&&
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 240 PM CST THU MAR 7 2013
LOW CLDS OFF LAKE SUPERIOR PROVED TOUGH TO DISLODGE
FM NRN WI THIS MORNING. BUT MARCH SUNSHINE WAS ABLE TO HELP
MIXING WORK THROUGH THE CLOUD LAYER...WITH ONLY SCT LOW CLDS NOW
REMAINING. HIGH AND MIDDLE CLDS WERE STREAMING IN FM THE W...AND
WL BE WORKING ACRS THE AREA TNGT. SFC RIDGE WL BE RIGHT ACRS THE
AREA...SO WINDS WL BE LIGHT. COUNTING ON HIGH AND MIDDLE CLDS TO
KEEP FG FROM GETTING OUT OF HAND. CONTD WITH PREV FCST OF JUST
HAVING PATCHY FOG DEVELOPING AFTER MIDNIGHT...AND CONTG INTO FRI
MORNING. ALSO COUNTING ON CLDS KEEPING TEMPS FROM GOING INTO FREE
FALL. BLENDED THE MIN OF THE VARIOUS GUID PRODUCTS WITH THE WITH
ECMWF AND BIAS-CORRECTED ECMWF...WHICH HAVE BEEN PERFORMING WELL
LATELY. THE RESULT WAS A LOWERING OF THE MINS IN MOST AREAS BY A
FEW DEGREES.
QUIET WX WL CONT FRIDAY. TEMPS SHOULD BE A FEW DEGREES WARMER THAN
TDA.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 240 PM CST THU MAR 7 2013
COMPLEX WEATHER PATTERN TAKING SHAPE ACROSS THE CONUS
DURING THE EXTENDED PERIOD. ALREADY NEED TO DEAL WITH APPROACHING
NRN STREAM SHORTWAVE TROF/CDFNT FRI NGT/SAT WITH PCPN TYPE ISSUES
ONGOING. THIS WL BE FOLLOWED BY THE WEAKENING SRN STREAM UPR LOW/
SFC WAVE ON THE CDFNT LIFTING NE SUNDAY NGT/MON. THERE ARE THEN
TIMING ISSUES WITH REGARDS TO A NRN STREAM CLIPPER SYSTEM AROUND
TUE AND FINALLY THERE ARE QUESTIONS AS TO THE OVERALL ORIENTATION
OF THE MEAN FLOW BY THE MIDDLE OF NEXT WEEK. THE ONLY WEATHER
ELEMENT THAT LOOKS FAIRLY STABLE WL BE TEMPS WHICH APPEAR TO BE
CLOSE TO NORMAL.
EVEN AT THIS LATE DATE...THE MDLS DISAGREE ON WHEN TO BRING PCPN
INTO NE WI STARTING LATE FRI NGT. THE NAM IS NOW SLOWER AND THE
GFS IS NOW FASTER. THE ONLY COMMON GROUND IS THAT THE HEAVIER PCPN
WL STILL BE TO OUR WEST AND SW FRI NGT ALONG A NE EXTENDED INVERTED
SFC TROF RUNNING FROM WRN NEBRASKA TO CNTRL MN. CLOUDS WL STEADILY
THICKEN THRU THE NGT AS A 40-50 KT S-SW LOW-LEVEL JET BRINGS GULF
MOISTURE NWD INTO THE WRN GREAT LAKES. EXPECT TO SEE THE LEADING
EDGE OF PCPN TO REACH CNTRL WI TOWARD DAYBREAK AND WITH SFC TEMPS
STIL EXPECTED TO BE BELOW FREEZING...THIS LEADS TO THE POSSIBILITY
OF MIXED PCPN AS WARMER AIR ALOFT ARRIVES. FCST SOUNDINGS INDICATE
THAT N-CNTRL WI WOULD REMAIN ALL SNOW...BUT WITH TEMPS JUST ABOVE
THE SFC CREEPING ABOVE 0C...CNTRL WI MAY SEE MORE OF A SNOW/SLEET
COMBINATION.
THE INVERTED SFC TROF IS PROGGED TO REMAIN WELL TO OUR WEST ON SAT...
HOWEVER THE COMBINATION OF A LEAD SHORTWAVE EJECTED NEWD FROM THE SRN
ROCKIES UPR LOW AND STRONG ISEN LIFT...WL BRING PCPN TO ALL OF NE WI.
PCPN TYPE REMAINS THE BIGGEST FCST CHALLENGE AS SFC TEMPS STRUGGLE TO
GET ABOVE THE FREEZING MARK SAT MORNING. SOUNDINGS CONT TO SHOW A
WARM LAYER JUST SLIGHTLY ABOVE 0C WHICH WOULD INDICATE A MIXED PCPN
POTENTIAL FOR ALL BUT THE LAKESHORE WHERE SE WINDS TO KEEP ANY PCPN
MORE RAIN. BY SAT AFTERNOON...CNTRL/E-CNTRL WI WARM UP SUFFICIENTLY
ENUF TO BRING MAINLY RAIN TO THIS PART OF THE FCST AREA. NRN WI
SHOULD SEE MORE OF A RAIN/SNOW MIX IN THE AFTERNOON AS SFC TEMPS GET
FAR ENUF ABOVE FREEZING.
AS THE ENTIRE SYSTEM SHIFTS EAST SAT NGT...THE INVERTED TROF BECOMES
MORE OF A CDFNT AND DRIVES EWD REACHING CNTRL WI BY 12Z SUNDAY.
VARIETY OF PCPN WL CONT OVER NE WI WITH RAIN OVER E-CNTRL WI...RAIN
BEGINNING TO MIX WITH SNOW LATE CNTRL/FAR NE WI AND A MIX CHANGING
TO ALL SNOW IN N-CNTRL WI. UP TO A COUPLE INCHES OF WET SNOW CANNOT
BE RULED OUT IN THE NORTH...OTHERWISE FOG MAY BECOME A BIGGER ISSUE
DUE TO SNOWMELT AND LIGHT WINDS IN THE VICINITY OF THE CDFNT. THE
CDFNT TO COMPLETE ITS PASSAGE THRU ERN WI SUNDAY MORNING...TO BE
FOLLOWED BY THE PASSAGE OF THE SHORTWAVE TROF SUNDAY AFTERNOON.
BETTER FORCING/LIFT TO ACCOMPANY THE CDFNT...THUS EXPECT HIGHER POPS
WOULD BE NECESSARY DURING THE MORNING HOURS. DESPITE COOLER AIR
CONTINUING TO FILTER INTO WI BEHIND THE FNT...THE MILD START TO THE
DAY MAY STILL ALLOW FOR PCPN TO REMAIN ALL RAIN OVER E-CNTRL AND
PARTS OF CNTRL WI SUNDAY AFTERNOON. THE NORTH SHOULD REMAIN ALL SNOW
AND WOULD NOT BE SURPRISED TO SEE AN ADDITIONAL LIGHT ACCUMULATION
OF SNOW. DO NOT ANTICIPATE MUCH OF A DIURNAL RISE IN TEMPS AS CAA
TAKES OVER THRU THE DAY. PERHAPS A 3 TO 5 DEG RISE FROM MORNING LOWS
IS ABOUT ALL WE WL ABLE TO MUSTER.
IT NOW APPEARS THAT THE SRN STREAM WEAKENING UPR LOW/SFC WAVE ON THE
OLD CDFNT WL PASS FAR ENUF TO OUR SE AS TO NOT HAVE ANY INFLUENCE ON
OUR WEATHER. INSTEAD...A RDG OF HI PRES IS FCST TO BUILD INTO THE WRN
GREAT LAKES SUNDAY NGT AND END THE GENERAL PCPN THREAT OVER NE WI.
NORTH WINDS COULD BRING A FEW FLURRIES ACROSS THE MI BORDER SUNDAY
NGT INTO MON...BUT EXPECT PARTLY CLOUDY SKIES TO PREVAIL WITH TEMPS
TO BE SLIGHTLY BELOW NORMAL. MDLS CONT TO HAVE DIFFERENT IDEAS ON THE
HANDLING OF A NRN STREAM CLIPPER-TYPE SYSTEM NEXT WEEK. THE ECWMF/
UKMET/GEM ARE FASTER/WEAKER WITH THE ASSOCIATED SFC LOW...WHILE THE
GFS IS SLOWER/STRONGER. AT THIS POINT...EITHER SOLUTION COULD END UP
BEING CORRECT...THUS HAVE TAKEN A DIPLOMATIC APPROACH (ESSENTIALLY
SPLITTING THE DIFFERENCE) WHICH ENDED UP BRINGING A SMALL CHC OF SNOW
INTO N-CNTRL WI MON NGT AND THEN A GENERAL CHC POP AREA-WIDE ON TUE.
LINGERING ISOLATED SNOW SHWRS OR FLURRIES ARE POSSIBLE TUE NGT...BUT
ANOTHER RDG OF HI PRES SHOULD BRING QUIET CONDITIONS ON WED. THE MAIN
FCST PROBLEM FOR THE MIDDLE OF NEXT WEEK WL BE THE ORIENTATION OF THE
MEAN FLOW AS THE ECMWF ADVERTISES A DEEPER ERN CONUS UPR TROF THAN
THE GFS. THIS DIFFERENCE WL BE KEY TO THE TIMING OF THE NEXT PACIFIC
SYSTEM WHICH WOULD ARRIVE WED NGT/THU (GFS) VERSUS THU NGT (ECWMF).
GENERAL CONSENSUS WOULD FAVOR THE ECMWF...THUS HAVE LEANED TOWARD
A DRY THU AS WELL.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1035 AM CST THU MAR 7 2013
CLOUDS HANGING TOUGH ACRS THE N. RAP RH PROGS SUGGEST THEY WL BE
TOUGH TO DISLODGE...AND COULD OVERSPREAD MUCH OF THE REST OF THE
AREA. BUT NOT READY TO GO ALONG WITH THAT AS MID-MARCH SUN SHOULD
HELP MIXING NR THE EDGES OF THE CLD BAND. WL STAY THE COURSE AND
HAVE A GRADUAL DECR IN CLDS ACRS THE N THIS AFTN. SOME MIDDLE AND
HIGH CLDS STREAMING ACRS RM THE W SHOULD PREVENT WIDESPREAD DENSE
FG OVERNIGHT. WL STICK WITH SOME OCNL MVFR CONDITIONS AS IN PREV
TAFS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......KALLAS
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1038 AM CST THU MAR 7 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY THROUGH FRIDAY.
CLOUDS AND TEMPERATURES CONTINUE TO BE THE ISSUE THIS PERIOD.
UPPER RIDGE TO BUILD IN OVER THE STATE THROUGH FRIDAY WITH SURFACE
RIDGE AXIS OVER CWA TONIGHT. STRUGGLING WITH TEMPERATURES EARLY
THIS MORNING...AS LOW CLOUDS SLOW TO EXIT THE FOX VALLEY AND
PARTS OF THE LAKESHORE. LAKE CLOUDS ALSO MOVING SOUTH INTO
NORTHERN WI. OVERNIGHT TEMPERATURES SHOWING SIG VARIABILITY...BOUNCING
AROUND AS CLOUDS MOVE IN AND OUT. TRENDS OFF SATELLITE...
SUBSIDENCE/LOWERING INVERSION HEIGHTS AND DIMINISHING LLVL WINDS
WOULD SUGGEST THE LOW CLOUDS WILL DIMINISH FAIRLY QUICKLY THIS
MORNING...LEAVING ONLY PASSING MID/HIGH CLOUDS. COLD START THIS
MORNING WOULD SUGGEST GOING BIT COOLER ON TODAYS HIGHS THAN
PREVIOUS FORECAST. GUIDANCE ALSO POINTING COLDER...THOUGH WITH
MARCH SUN AND PERSONAL BIAS TOWARDS BEING COLD ON THESE SHIFTS
WILL NOT MAKE ANY SIG CHANGE.
SURFACE RIDGE AXIS OVER STATE TONIGHT WITH LIGHT WINDS. ADDED
PATCHY FOG TO FORECAST BASED ON UPSTREAM TRENDS. TEMP FALL TO BE
LIMITED SOME BY MID/HIGH CLOUDS. WARMER ON FRI WITH SOUTHWEST
FLOW ALOFT. 850 MB TEMPS FLOATING WITH ZERO BY END OF DAY.
.LONG TERM...FRIDAY NIGHT THROUGH NEXT WEDNESDAY.
THE MAIN FOCUS OF THIS PORTION OF THE FORECAST IS THE PRECIPITATION
IMPACTS FROM A COLD FRONT PASSING ACROSS THE STATE SATURDAY INTO
SUNDAY. MEDIUM RANGE MODELS TONIGHT HAVE TIMING DIFFERENCES WITH
THE SW CONUS UPPER LOW AS IT TRACKS ACROSS THE CENTRAL PLAINS THIS
WEEKEND TOWARDS THE GREAT LAKES. THE GFS AND GEM ARE NOTABLY ON THE
FASTER SIDE OF THE SOLUTION ENVELOP STARTING BY 00Z SUNDAY COMPARED
TO THE ECMWF AND NAM. THE LATTER MODELS HAVE MORE SUPPORT FROM THE
GFS ENSEMBLE MEAN AND WILL STICK WITH THOSE MODELS...AS THEY ALSO
HAVE SUPPORT FROM HPC.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...STRONG WARM ADVECTION WILL BE
OCCURRING ACROSS THE GREAT PLAINS AND SOUTH-CENTRAL CANADA FRIDAY
NIGHT AHEAD OF STRONG SHORTWAVES CONVERGING WITHIN THE NORTHERN AND
SOUTHERN BRANCH OF THE JET STREAM. PRECIPITATION WILL BE SPREADING
NORTHEAST ACROSS THE PLAINS...ON THE NOSE OF A 45-50 KT LLJ....AND
SHOULD BE APPROACHING THE NORTHERN MISSISSIPPI VALLEY BY LATE FRIDAY
NIGHT. BOTH THE NAM AND ECMWF SHOW DRY SE FLOW IN THE LOW LEVELS
OCCURRING FRIDAY NIGHT...WHICH WILL HAVE TO BE OVERCOME FOR PRECIP
TO REACH THE GROUND. THE PREVIOUS SHIFT INCREASED POPS TO MATCH
OFFICES TO OUR WEST...BUT EVIDENCE IS NOT THERE TO INCREASE POPS
FURTHER. THIS CHANGES INTO SATURDAY AS THE WARM ADVECTION SPREADS
ACROSS THE WESTERN GREAT LAKES. THE NOSE OF THE 850MB THETAE AXIS
POINTS TOWARDS CENTRAL MINNESOTA AND WESTERN WISCONSIN AND THIS IS
WHERE THE HEAVIEST PRECIP SHOULD RESIDE. BUT ENOUGH MOISTURE SHIFTS
INTO THE AREA THAT LIGHT PRECIP SHOULD ARRIVE INTO NORTH-CENTRAL
WISCONSIN SATURDAY MORNING. PTYPE UPON ARRIVAL OF THE PRECIP
REMAINS MESSY. THE SREF PORTRAYS A FAIRLY HIGH THREAT OF FREEZING
RAIN OVER CENTRAL AND NORTH-CENTRAL WISCONSIN SATURDAY MORNING. BUT
PROGGED SOUNDINGS INDICATE MAINLY A SNOW/SLEET THREAT AS PRECIP
DYNAMICALLY COOLS THE COLUMN. ENOUGH WARM ADVECTION SHOULD OCCUR BY
AFTERNOON THAT A MIXED PRECIP THREAT IS DIMINISHED AS SURFACE TEMPS
RISE ABOVE FREEZING EVEN OVER NORTH-CENTRAL WISCONSIN. WILL BACK
OFF PRECIP AMOUNTS ON SATURDAY...BUT NORTH-CENTRAL WISCONSIN COULD
STILL SEE AN INCH OR TWO OF SNOW BY SATURDAY EVENING.
MOST OF THE PRECIP SHOULD BE FALLING SATURDAY NIGHT AS THE COLD
FRONT WORKS ACROSS THE STATE. INCREASING UPPER DIVERGENCE AND
MID-LEVEL FGEN WILL SUPPORT A WIDESPREAD BAND OF PRECIP THAT SHOULD
MOSTLY FALL AS RAIN EXCEPT OVER N-C WISCONSIN WHERE A RAIN/SNOW MIX
WILL CHANGE OVER TO SNOW. WILL SLOW DOWN THE TRANSITION TO SNOW AS
THE COLDER AIR LOOKS TO BE SLOWER ARRIVING BEHIND THE FRONT. THERE
HAS BEEN SOME CONCERN ABOUT PRECIP AMOUNTS LEADING TO FLOODING.
INITIAL GUESS POINTS TOWARDS A QUARTER TO A HALF INCH OF PRECIP WILL
FALL. HEAVIER AMOUNTS MAY SPLIT THE REGION TO THE NORTH AND
SOUTH...DIRECTLY AHEAD OF THE SHORTWAVES. UNLESS THERE IS MORE
EVIDENCE THAT THE NOSE OF A LLJ WORKS INTO THE AREA...THINK FLOODING
POTENTIAL IS MINOR. BELIEVE E-C WISCONSIN STANDS THE BEST CHANCE
THOUGH...IF WERE FORCED TO PICK AN AREA THAT COULD SEE SOME
FLOODING. WILL CONTINUE TO HIGHLIGHT THREAT IN THE HWO UNTIL
EVIDENCE BECOMES MORE CLEAR.
REST OF THE FORECAST...THE FRONT WILL FINISH CROSSING THE EASTERN
PART OF THE FORECAST AREA ON SUNDAY AND LIGHT PRECIP WILL BE ONGOING
SUNDAY MORNING. PTYPE WILL BE GRADUALLY CHANGING FROM RAIN TO SNOW
OVER CENTRAL AND NORTHEAST WISCONSIN OVER THE COURSE OF THE DAY.
ANY SNOW AMOUNTS WILL LIKELY BE UP TO AN INCH. PRECIP PUSHES TO THE
SOUTHEAST SUNDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA ON
MONDAY...WHEN WE SHOULD HAVE A PERIOD OF CLEARING SKIES. BUT A
CLIPPER SYSTEM WILL QUICKLY ARRIVE MONDAY NIGHT AND PASS OVER THE
AREA ON TUESDAY...WHICH WILL RETURN SNOW CHANCES. COULD SEE AN INCH
OR TWO OUT OF THIS CLIPPER. HIGH PRESSURE RETURNS ON WEDNESDAY.
COULD SEE A BIG WARMUP AT THE END OF THE WEEK THOUGH.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1035 AM CST THU MAR 7 2013
CLOUDS HANGING TOUGH ACRS THE N. RAP RH PROGS SUGGEST THEY WL BE
TOUGH TO DISLODGE...AND COULD OVERSPREAD MUCH OF THE REST OF THE
AREA. BUT NOT READY TO GO ALONG WITH THAT AS MID-MARCH SUN SHOULD
HELP MIXING NR THE EDGES OF THE CLD BAND. WL STAY THE COURSE AND
HAVE A GRADUAL DECR IN CLDS ACRS THE N THIS AFTN. SOME MIDDLE AND
HIGH CLDS STREAMING ACRS RM THE W SHOULD PREVENT WIDESPREAD DENSE
FG OVERNIGHT. WL STICK WITH SOME OCNL MVFR CONDITIONS AS IN PREV
TAFS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MPC
AVIATION.......SKOWRONSKI