Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/01/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
210 PM MST SUN DEC 30 2012
.SYNOPSIS...THERE IS A GOOD CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW
THIS EVENING INTO MONDAY WITH SNOW ACCUMULATIONS AS LOW AS 3500
FEET. DRY CONDITIONS WILL THEN PREVAIL NEW YEARS DAY THROUGH
SATURDAY WITH A GRADUAL WARMING TREND.
&&
.DISCUSSION...UPPER TROUGH CONTINUES TO DEEPEN OVER THE SWRN CONUS
THIS AFTERNOON. UPPER LOW IS PROGGED TO MOVE EWD ACROSS NRN ARIZONA
TONIGHT...THEN SYSTEM WILL FILL AND MOVE RAPIDLY EWD INTO THE
CENTRAL CONUS PLAINS BY MON EVENING. 30/12Z UNIV OF ARIZONA WRF-NAM
AND WRF-GFS AS WELL AS THE 30/15Z RUC HRRR WERE VERY SIMILAR WITH
DEPICTING TWO PERIODS OF PRECIP ACROSS SE AZ TONIGHT. THE FIRST
PERIOD OF PRECIP IS FORECAST TO OCCUR BASICALLY FROM 6-10 PM MST OR
SO. MORE SHOWERS ARE PROGGED TO MOVE INTO WRN/CENTRAL PIMA COUNTY
AROUND MIDNIGHT...THEN WIDESPREAD VALLEY RAIN/MOUNTAIN SNOW TO OCCUR
LATE TONIGHT INTO MID-MORNING MON.
BASED ON THESE SOLUTIONS AS WELL AS THE 30/12Z NAM/GFS/ECMWF...HAVE
MAINTAINED THE INHERITED WINTER WEATHER ADVISORY FOR AZZ503-506>509
FROM MIDNIGHT TONIGHT TO 9 AM MST MONDAY ABOVE 3500 FEET. STILL
APPEARS THAT SNOW LEVELS LATE TONIGHT INTO MON MORNING WILL RANGE
FROM 3500-4000 FEET. PRECIP MON AFTERNOON TO BE CONFINED MOSTLY TO
GREENLEE...GRAHAM...AND COCHISE COUNTIES EAST OF TUCSON. DRY
CONDITIONS TO OCCUR MON NIGHT EXCEPT FOR A SLIGHT CHANCE OF SNOW
SHOWERS ACROSS THE WHITE MOUNTAINS.
STORM TOTAL LIQUID AMOUNTS ARE EXPECTED TO RANGE FROM ABOUT ONE
TENTH OF AN INCH TO NEARLY ONE THIRD OF AN INCH. STORM TOTAL SNOW
ACCUMULATIONS ABOVE 5000 FEET ARE FORECAST TO RANGE FROM 2-5
INCHES...OR JUST BELOW SNOW ADVISORY CRITERIA. HOWEVER...SNOW
ACCUMULATIONS OF 1 TO 2 INCHES BETWEEN 3500-5000 FEET JUSTIFY THE
WINTER WEATHER ADVISORY FOR THE LOWER ELEVATIONS OF GRAHAM/SRN
GREENLEE/COCHISE/ERN SANTA CRUZ/ERN PINAL COUNTIES.
DRIER NWLY/WLY FLOW ALOFT TUE...THEN GFS/ECMWF WERE SIMILAR WITH
MOVING THE NEXT UPPER LOW SEWD ACROSS NRN BAJA CALIFORNIA TUE NIGHT
AND EARLY WED. AT THIS TIME APPEARS THAT DRY CONDITIONS WILL OCCUR
TUE NIGHT-WED AS BULK OF MOISTURE WILL BE ABOVE 500 MB. UPPER RIDGE
TO THEN PREVAIL OVER THE WRN CONUS THUR-SAT. REMAINING DRY NEXT SUN
AS THE NEXT UPPER LOW IS PROGGED TO BE WELL WEST OF THE AREA.
MARKEDLY COLDER MON WITH HIGH TEMPS TO BE NEARLY 15 DEGS F OR SO
BELOW NORMAL. ALTHOUGH FAIRLY WIDESPREAD FREEZING TEMPS ARE FORECAST
TO OCCUR MON NIGHT...A HARD FREEZE APPEARS TO BE UNLIKELY. A VERY
GRADUAL WARMING TREND IS ON TAP TUE-SAT ALTHOUGH DAYTIME TEMPS ARE
EXPECTED TO REMAIN BELOW NORMAL.
&&
.AVIATION...CLOUD LOWERING TO GENERALLY 4-7K FT AGL THIS EVENING AND
CONTINUING THRU MONDAY MORNING. WIDESPREAD -SHRA AND HIGHER TERRAIN
-SHSN THIS EVENING THRU MONDAY MORNING. AREAS OF MVFR CIGS TONIGHT
WITH HIGHER TERRAIN OBSCURATIONS. SCT -SHRA/MTN -SHSN MAINLY EAST OF
KTUS MONDAY AFTERNOON. CLOUDS DECREASING WEST OF KTUS MONDAY
AFTERNOON WITH BKN-OVC CLOUDS MOSTLY AROUND 4-7K FT AGL EAST OF
KTUS. AREAS OF S-SW SURFACE WIND THIS EVENING 10-20 KTS WITH GUSTS
TO 30 KTS EAST AND SOUTH OF KTUS. SURFACE WIND AFTER 31/06Z EASING
TO LESS THAN 10 KTS THRU MONDAY AFTERNOON. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...RAIN AND MOUNTAIN SNOW SHOWERS WILL MOVE ACROSS THE
AREA THIS EVENING THROUGH EARLY MONDAY WITH A FEW SCATTERED SHOWERS
MONDAY AFTERNOON. THE SOUTH TO SOUTHWEST BREEZE ACROSS PORTIONS OF
THE AREA WILL EASE OVERNIGHT. THEN DRY CONDITIONS WILL PREVAIL FROM
TUESDAY THROUGH NEXT WEEKEND WITH A VERY GRADUAL WARMING TREND.
WINDS WILL BE LIGHT THROUGH THE PERIOD AND PREDOMINATELY FROM AN
EASTERLY DIRECTION.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM MST MONDAY
FOR AZZ503-506>509 BETWEEN 3500 AND 5000 FEET.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...BF
AVIATION/FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
930 PM EST MON DEC 31 2012
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT FARTHER OFFSHORE TONIGHT. A COLD FRONT
WILL SLOWLY APPROACH FROM THE NORTHWEST TUESDAY NIGHT...THEN STALL
JUST OFF THE COAST WEDNESDAY. A WAVE OF LOW PRESSURE WILL MOVE
ALONG THE LINGERING BOUNDARY EARLY THURSDAY...BEFORE HIGH PRESSURE
BUILDS INTO THE REGION FRIDAY THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A BAND OF THICK MID-LEVEL CLOUDS HAS SPREAD EAST ROUGHLY ALONG AND
NORTH OF I-16. AFTER FALLING QUICKLY THIS EVENING...TEMPERATURES
FALLS HAVE EITHER STOPPED OR EVEN REVERSED WHERE THE CLOUD COVER
IS THE THICKEST. RAP 700MB RH PROGS SHOW THE SOUTHERN EDGE OF THE
MID-LEVEL CLOUD DECK BUCKLING SLIGHTLY NORTH AFTER MIDNIGHT AS
THE MID-LEVEL FLOW BEGINS TO VEERS SLIGHTLY OVERNIGHT...BUT IT
DOES APPEAR CLOUDY SKIES WILL LINGER FOR MUCH OF THE NIGHT ROUGHLY
ALONG AND NORTH OF A METTER-BEAUFORT LINE...INCLUDING THE
CHARLESTON METRO AREA. THE SAVANNAH METRO AREA LOOKS TO BE RIGHT
ON THE EDGE...BUT SUSPECT SKIES WILL GENERALLY REMAIN PARTLY
CLOUDY THERE THROUGH SUNRISE ALTHOUGH THERE WILL LIKELY BE A FEW
MOSTLY CLOUDY TO CLOUDY SPELLS THROUGH MIDNIGHT. FARTHER SOUTH...
MOSTLY CLEAR SKIES WILL GRADUALLY GIVE WAY TO INCREASING CIRRUS
AND THE COLDEST TEMPERATURES WILL ACTUALLY BE FOUND THERE NEW
YEARS MORNING. HAVE ADJUSTED THE HOURLY TEMPERATURE AND SKY COVER
FORECASTS TO REFLECT GOING TRENDS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...THE FORECAST AREA WILL REMAIN ON THE NORTHWEST PERIPHERY
OF DEEP LAYERED RIDGING THROUGH THE MAJORITY OF THE DAY...BEFORE A
COLD FRONT SLOWLY SLIPS TOWARD THE REGION OVERNIGHT. DESPITE
INCREASING CLOUD COVER FROM THE WEST...SOLID SOUTH/SOUTHWEST FLOW
AND ASSOCIATED WARM ADVECTION WILL SUPPORT NOTABLY WARMER
TEMPERATURES TUESDAY AFTERNOON. EXPECT HIGH TEMPERATURES TO
GENERALLY RANGE FROM THE LOW TO MID 60S...EXCEPT POSSIBLY THE
UPPER 60S SOUTH OF INTERSTATE 16 IN SOUTHEAST GEORGIA. THE
LINGERING RIDGE SHOULD CONFINE SHOWER ACTIVITY JUST WEST OF THE
FORECAST AREA UNTIL AT LEAST MID TO LATE AFTERNOON...AND HAVE
DELAYED THE INTRUSION OF PRECIPITATION INTO EASTERN SECTIONS
ACCORDING TO SLOWER MODEL TRENDS. THE FRONT WILL BECOME PARALLEL TO
FLAT RIDGING ALOFT AS IT DROPS INTO THE SOUTHEAST STATES...SLOWING
ITS PROGRESS AND ULTIMATELY CAUSING IT TO STALL ALONG THE
COASTLINE BY DAYBREAK WEDNESDAY. HAVE INDICATED BEST RAIN CHANCES
BETWEEN MIDNIGHT AND SUNRISE...WHEN THE FRONT WILL BE LOCATED
DIRECTLY OVER THE REGION. THERE IS SOME QUESTION AS TO HOW MUCH
PRECIPITATION WILL ACTUALLY ACCOMPANY THIS SYSTEM...ESPECIALLY
CONSIDERING THE LACK OF ANY SIGNIFICANT UPPER LEVEL FORCING AND
ANY TAP INTO DEEPER MOISTURE TO THE SOUTH/SOUTHEAST.
WEDNESDAY...THE WEAKENING FRONT WILL MEANDER JUST ALONG OR JUST
OFF THE COASTLINE DURING THE DAYTIME HOURS...KEEPING BEST MOISTURE
AND CONVERGENCE MAINLY ACROSS THE EASTERN HALF OF THE FORECAST
AREA. WILL CONTINUE TO INDICATE SLIGHT CHANCE TO LOW CHANCE POPS
THROUGH WEDNESDAY AFTERNOON...HIGHEST CLOSER TO THE COAST. ALTHOUGH
LOW LEVEL FLOW WILL BECOME NORTH BEHIND THE FRONT...MID AND UPPER
LEVEL WINDS WILL REMAIN FROM THE WEST. COLD ADVECTION WILL THUS
BE WEAK TO NONEXISTENT...AND EXPECT ONLY A SLIGHT DECREASE IN
HIGH TEMPERATURES INTO THE LOWER 60S AS A RESULT. THE PATTERN WILL
BECOME MORE CONDUCIVE TO PRECIPITATION AFTER MIDNIGHT WEDNESDAY
NIGHT/EARLY THURSDAY MORNING...AS SHORTWAVE ENERGY MOVING NORTH
FROM THE GULF OF MEXICO AND DOWNSTREAM OF AN UPPER TROUGH PROVIDES
THE SUPPORT TO SPIN UP A WEAK WAVE OF LOW PRESSURE ALONG THE
LINGERING COASTAL FRONT. PRECIPITATION POTENTIAL WILL THUS
INCREASE OVERNIGHT AS DEEPER MOISTURE STREAMS UP FROM THE
SOUTHWEST. HAVE INDICATED POPS RISING INTO THE 40 PERCENT RANGE
AFTER 00Z/SUNSET.
THURSDAY...RAIN CHANCES INCREASE FURTHER INTO THURSDAY...AS THE
COASTAL WAVE STRENGTHENS AND PULLS NORTHEAST UNDER THE INFLUENCE
OF THE APPROACHING TROUGH ACROSS THE OHIO/TENNESSEE VALLEYS. GOOD
MODEL CONSISTENCY ADDS CONFIDENCE TO THE PRECIPITATION
FORECAST...AND HAVE MAINTAINED LIKELY POPS AROUND 60 PERCENT
THROUGH THE DAYTIME HOURS. STRONGEST COLD ADVECTION WILL BE
DELAYED UNTIL THE OVERNIGHT PERIOD...HOWEVER DECENT RAIN COVERAGE
COMBINED WITH CONTINUED NORTHERLY FLOW AND THICK CLOUD COVER WILL
KEEP TEMPERATURES SUPPRESSED IN THE LOW 50S INLAND TO UPPER 50S
SOUTHEAST GEORGIA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL BUILD IN FRIDAY THROUGH THE UPCOMING WEEKEND. THE
31/00Z ECMWF WAS SHOWING A SECONDARY SHORTWAVE MOVING THROUGH FRIDAY
NIGHT AND SATURDAY...WITH THE POTENTIAL FOR ANOTHER SURFACE LOW
MOVING UP THE COAST. THIS IS QUITE DIFFERENT FROM PREVIOUS
RUNS...SO PREFER TO STICK CLOSER TO THE GFS THAT KEEPS THE
PRECIPITATION WELL OFFSHORE. TEMPERATURES WILL BEGIN WARMING BACK
UP TO NEAR NORMAL BY LATE IN THE PERIOD.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
AVIATION CONCERN REVOLVES AROUND FOG/STRATUS POTENTIAL TONIGHT.
LATEST MODEL SOUNDINGS ARE SHOWING SMALL T/TD SPREADS OVERNIGHT. ONE
BIG LIMITING FACTOR FOG FOG WILL BE THE AMOUNT OF CLOUD COVER
PRESENT. CURRENT SATELLITE SHOWS MID LEVEL CLOUD DECK OVER WESTERN
GA AND SC STARTING TO EDGE EASTWARD. HAVE DECIDED TO REMOVE MENTION
OF FOG FOR NOW. HOWEVER GIVEN THE LOW LEVEL MOISTURE CANNOT RULE OUT
SOME STRATUS DEVELOPMENT...HAVE OPTED TO LEAVE IN SCT LAYER AND WILL
CONTINUE TO MONITOR. FOR TOMORROW...HIGH PRESSURE WILL SHIFT EAST AS
A COLD FRONT APPROACHES FROM THE NORTHWEST. THIS WILL RESULT IN AN
INCREASE IN CLOUD COVER AND LOWERING OF VFR CIGS DURING THE DAY.
PRECIPITATION ASSOCIATED WITH THE FRONT SHOULD HOLD OFF UNTIL AFTER
THE END OF THIS TAF CYCLE.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CEILINGS LIKELY LATE
TUESDAY NIGHT INTO WEDNESDAY...ALONG WITH POSSIBLE VSBY RESTRICTIONS
IN RAIN/FOG. ANOTHER ROUND OF RESTRICTIONS EXPECTED LATE WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT...AS LOW PRESSURE MOVES UP THE COAST.
&&
.MARINE...
TONIGHT...OVERALL A FAIRLY QUIET PERIOD WITH HIGH PRESSURE
POSITIONED JUST OFF TO THE EAST. WINDS WILL BECOME MORE SW BY EARLY
TUESDAY MORNING WITH AN UPTICK IN SPEEDS THANKS TO AN INCREASING LOW
LEVEL JET. STILL EXPECT WINDS TO BE 15 KTS OR LESS...BEING HIGHEST
OFF THE SC WATERS. EXPECT SOME STRATOCUMULUS WITH PERHAPS AN
ISOLATED SHOWER OR TWO BEYOND 20 NM...BUT MAINLY DRY. SEAS WILL BE 2
FT OR LESS NEARSHORE...WITH SOME 4 FOOTERS BEING INTRODUCED OVER THE
OUTER WATERS VERY LATE.
SOUTHWEST WINDS WILL INCREASE TUESDAY AND TUESDAY NIGHT...BEFORE
SHIFTING TO THE NORTH AS A COLD FRONT SLIPS JUST OFFSHORE. SEAS
COULD BUILD AS HIGH AS 5 FT OVER OUTER PORTIONS OF THE MARINE
ZONES TUESDAY NIGHT. AT THIS POINT...CONDITIONS ARE EXPECTED TO
REMAIN JUST BELOW ADVISORY CRITERIA. ANOTHER SURGE IS EXPECTED
THURSDAY/THURSDAY NIGHT WITHIN STRONGER COLD ADVECTION...AS A WAVE
OF LOW PRESSURE DEVELOPS ALONG THE LINGERING FRONT AND PULLS TO THE
NORTHEAST. MARGINAL SMALL CRAFT ADVISORY CONDITIONS COULD BE
POSSIBLE LATE THURSDAY INTO EARLY FRIDAY AS A RESULT.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/ECT
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1248 AM EST SUN DEC 30 2012
.SYNOPSIS...
A REINFORCING COLD FRONT WILL MOVE THROUGH THIS EVENING FOLLOWED
BY HIGH PRESSURE THROUGH SUNDAY WHICH WILL THEN SHIFT OFFSHORE BY
MONDAY. ANOTHER FRONTAL SYSTEM WILL DROP INTO THE SOUTHEAST UNITED
STATES TUESDAY AND PERSIST IN THE VICINITY THROUGH THURSDAY NIGHT.
HIGH PRESSURE WILL BUILD BACK IN FOR LATE NEXT WEEK INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MAINLY CLEAR SKIES AND COLDER TEMPS OVERNIGHT. VERY FEW/MINOR
CHANGES ON THE MIDNIGHT PACKAGE. SURFACE WINDS HAVE BEEN QUITE
GUSTY OVER LAND AREAS FOR THIS TIME OF NIGHT DUE TO COLD AIR
ADVECTION. AS HIGH PRES BUILDS LATER TONIGHT...GUSTS WILL SUBSIDE
AND SPEEDS SHOULD DIMINISH TO 10 MPH OR LESS NEARING DAWN.
LAKE WINDS...A LAKE WIND ADVISORY REMAINS IN FORCE UNTIL 5 AM
SUNDAY FOR LAKE MOULTRIE. GUSTY WINDS WILL CONTINUE AS A STRONGER
SURGE OF COLD AIR MOVES ACROSS THE RELATIVELY WARMER LAKE WATERS.
WAVES OF 1-2 FT WILL OCCUR...HIGHEST OVER THE CENTRAL AND
SOUTHEAST PORTIONS OF THE LAKE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/...
SUNDAY AND SUNDAY NIGHT...LARGE AND PROMINENT RIDGING ALOFT WILL
BUILD IN FROM THE WEST. AT THE SURFACE...A 1030 MB HIGH WILL SHIFT
EASTWARD INTO THE FORECAST AREA AND LINGER THROUGH THE OVERNIGHT.
DEEP DRY AIR AND LARGE SCALE SUBSIDENCE WILL RESULT IN A DRY AND
CLEAR DAY/NIGHT. COLD AIR ADVECTION WILL CONTINUE THROUGH THE DAY
RESULTING IN COOL HIGH TEMPS. LOW LEVEL THICKNESSES SUPPORT HIGHS
STRUGGLING TO REACH THE LOW 50S. WITH EXCELLENT RADIATIONAL COOLING
CONDITIONS SUNDAY NIGHT...LOWS WILL BOTTOM OUT IN THE UPPER 20S AWAY
FROM THE COAST.
MONDAY THROUGH TUESDAY...THE UPPER RIDGE WILL FLATTEN OUT AND THE
FLOW WILL BECOME MORE ZONAL IN RESPONSE TO A POSITIVELY TILTED
TROUGH PUSHING INTO THE OH VALLEY. AS A RESULT A STRENGTHENING 150
KT UPPER LEVEL JET WILL EXTEND WEST TO EAST ACROSS THE UPPER MIDWEST
AND MID ATLANTIC. THIS WILL HELP DRIVE SURFACE LOW AND COLD FRONT
DEVELOPMENT OVER THE LOWER MS VALLEY BY TUESDAY MORNING. THE FRONT
WILL CONTINUE TO DRIFT EASTWARD WITH PRECIP EXPECTED TO BE OUR THE
DOORSTEP OF THE FORECAST AREA BY TUESDAY AFTERNOON. EXPECT MONDAY TO
BE DRY WITH INCREASING HIGH CLOUDS AND TEMPS RIGHT AROUND NORMAL.
TUESDAY CONTINUES TO FEATURE A DRY MORNING AND POPS INCREASING INTO
THE CHANCE RANGE FOR THE AFTERNOON. AS OF RIGHT NOW...MODELS ARE IN
GOOD AGREEMENT KEEPING THE BULK OF THE PRECIP TO OUR WEST THROUGH
THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
TUESDAY NIGHT THROUGH THURSDAY NIGHT LOOK FAIRLY ACTIVE DUE TO A
PLETHORA OF UPPER DISTURBANCES RIPPLING THROUGH THE BROAD EASTERN
UNITED STATES TROUGH. A WEAK FRONT SHOULD REMAIN DRAPED ACROSS THE
FORECAST AREA WITH NUMEROUS SURFACE WAVES RIDING ALONG IT. WE KEPT
CHANCE POPS IN THE FORECAST THROUGH THURSDAY...TAPERING OFF THURSDAY
NIGHT. COOL...DRY HIGH PRESSURE WILL BUILD IN FRIDAY THROUGH
SATURDAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
VFR AT KSAV/CHS THROUGH 06Z/31. ENHANCED SURFACE WIND GUSTS WILL
SLOWLY DROP OFF OVERNIGHT.
EXTENDED AVIATION OUTLOOK...INCREASING CHANCES FOR SUB-VFR
CONDITIONS LATE TUESDAY AND WEDNESDAY AS A COLD FRONT DROPS SOUTH
INTO THE AREA.
&&
.MARINE...
TONIGHT...WINDS WILL INCREASE EVEN MORE TONIGHT AS A SECONDARY
SURGE OF COLD AIR PUSHES OFF THE COAST AND INTERACTS WITH THE
RELATIVE WARMER ATLANTIC WATERS. SMALL CRAFT ADVISORIES LOOKS WELL
PLACED...BUT OPTED TO UPGRADE TO A GALE WARNING FOR THE GEORGIA
OFFSHORE WATERS WHERE SIGNIFICANTLY WARMER WATERS ASSOCIATED WITH
THE WESTERN WALL OF THE GULF STREAM ARE LOCATED. YESTERDAY/S 1KM
MODIS SEA SURFACE TEMPERATURE DATA INDICATED WATER TEMPERATURES
QUICKLY WARM FROM THE LOWER-MID 50S AROUND 20 NM TO THE LOWER 70S
BEYOND 40 NM. RUC AND H3R BOUNDARY LAYER WIND FORECAST SUGGEST
WINDS COULD EASILY REACH SOLID GALES OF 30-35 KT WITH GUSTS TO 40
KT IN THE OUTER HALF OF THE GEORGIA OFFSHORE ZONES WHERE THE
WARMER WATER TEMPERATURES WILL FAVOR MORE INTENSE VERTICAL MIXING.
OBSERVATIONS FROM 41004 WERE ALREADY GUSTING NEAR 35 KT AT 29/22Z
SO THINK A GALE WARNING IS CERTAINLY WARRANTED ATTM AS WINDS
INCREASE FURTHER. WILL WORD THE HIGHEST WINDS BEYOND 40 NM IN
BOTH THE GALE WARNING ITSELF AND THE COASTAL WATERS FORECAST. SEAS
WILL BUILD AS HIGH 9 FT OFFSHORE...BUT WILL ACTUALLY SUBSIDE A
BIT NEAR THE IMMEDIATE COAST AS THE OFFSHORE FLOW INTENSIFIES.
SUNDAY THROUGH THURSDAY...HIGH PRESSURE WILL BUILD INTO THE AREA ON
SUNDAY. THE MORNING WILL CONTINUE TO SEE ELEVATED SEAS AND STRONG NW
WINDS AS THE WATERS ARE CAUGHT IN THE PINCHED GRADIENT BETWEEN THE
APPROACHING HIGH AND DEPARTING LOW. CONDITIONS SHOULD IMPROVE
QUICKLY INTO THE AFTERNOON...ALLOWING FOR ALL SMALL CRAFT ADVISORIES
TO COME DOWN. THINGS WILL THEN BE QUIET THROUGH MONDAY AS THE HIGH
PASSES OVER THE AREA. INCREASING SOUTHWEST FLOW AHEAD OF THE NEXT
FRONT MAY PUSH WINDS AS HIGH AS 15-20 KT WITH SEAS REACHING 5 FT
OVER THE OUTER PORTIONS BY TUESDAY. A STRONGER SURGE WILL OCCUR LATE
NEXT WEEK WHEN COLD HIGH PRESSURE BUILDS OVER THE WATERS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST THIS MORNING FOR AMZ330-
350-352-354.
GALE WARNING UNTIL 5 AM EST EARLY THIS MORNING FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...BSH
LONG TERM...BSH
AVIATION...
MARINE...ST
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1157 PM CST SAT DEC 29 2012
.DISCUSSION...
ISSUED 859 PM CST SAT DEC 29 2012
CLEARING EVIDENT ON SAT IMAGERY AND RAPID COOLING ALREADY TAKING
PLACE. DROPPED TEMPS A COUPLE OF DEGREES...AND ADDED WORDING FOR
POTENTIAL PATCHY FOG DEVELOPMENT. HAVE NOT LOST LLVL MOISTURE...
PARTICULARLY IN THE SW...AND IN THE NORTH...THE DEWPOINTS ARE A
LITTLE HIGHER...BUT THE TEMPS ARE DROPPING A LITTLE LOWER...AND
QUICKLY. FOR THE MOST PART THOUGH...FORECAST IS LOOKING GOOD.
CHANGED SOME TRENDS HERE AND THERE...FRESHENED THE HRLY TEMPS AND
THE SKY GRIDS. ZONES OUT MOMENTARILY.
&&
.AVIATION...
ISSUED 1152 PM CST SAT DEC 29 2012
CLEAR SKIES OVERNIGHT MAY END UP WITH PATCHY REDUCTIONS IN VIS
OVERNIGHT...BUT SPARSE ENOUGH NOT WILLING TO PUT IN ANY OF THE TAF
SITES JUST YET. TIMING OF CIRRUS RETURN IN MODELS A BIT DIFFERENT
FROM GFS TO NAM...AND THIS TIME TOMORROW NIGHT SHOULD ALSO SEE
SOME MID LEVEL CLOUDS MOVING INTO THE REGION. UNTIL THEN...VFR
AND CLOUDS BECOMING INCREASINGLY SOUTHERLY BY MIDDAY TOMORROW.
HJS
&&
.PREV DISCUSSION...
ISSUED 220 PM CST SAT DEC 29 2012
THE MAIN CONCERN IS THE STORM SYSTEM FOR MONDAY AND NEW YEARS EVE.
MAJOR DIFFERENCES ARE STILL SHOWING UP BETWEEN THE MODELS ON THIS
ONE. THE NAM IS MUCH STRONGER AND FARTHER NORTH WITH THE BAND OF
HEAVY SNOW...INDICATING 4-7 INCHES OF SNOW ACROSS A LARGE PORTION
OF CENTRAL IL...NORTH OF I-70. PART OF THAT HAS TO DO WITH ITS
CONTINUATION OF STEADY SNOWS IN THE NORTH OVERNIGHT NEW YEARS
EVE...WHERE THE OTHER MODELS DROP PRECIP OFF IN THE EVENING. THAT
ADDITIONAL SNOW SEEMS TO BE LINKED TO THE NAM BEING THE ONLY
MODEL TO TAKE A LOW PRESSURE CENTER ACROSS SOUTHERN ILLINOIS NEW
YEARS EVE NIGHT.
THE CANADIAN GEM HAS A SIMILAR PATH FOR THE SNOW BAND AS THE
NAM...BUT HAS LESS ACCUMULATION. THE ECMWF/GFS/UKMET ARE ALL
MUCH FARTHER SOUTH AND WEAKER WITH THE DYNAMICS/PRECIP IN OUR
AREA. THEY DO INDICATE 2-3 INCHES COULD ACCUMULATE SOUTHEAST OF
I-70...WITH THE NORTHERN EDGE OF 1 INCH NEAR I-72. THAT IS THE
PATH THAT HPC HAS GENERALLY FOLLOWED...AND WE WERE PRIMARILY
INDICATING THAT IN OUR GRIDS. HOWEVER...THE NAM AND RAP WERE THE
ONLY MODELS TO SHOW THE AMOUNT OF SNOW WE PICKED UP IN OUR
SOUTHEAST COUNTIES LAST NIGHT...SO THAT LEAVES SOME UNEASY CONCERN
FOR SUCH A BUSY HOLIDAY NIGHT...IF THAT SNOW BAND DOES SHIFT
NORTH.
WE WILL GENERALLY STAY THE COURSE FOR NOW AND ADJUST AMOUNTS
SLIGHTLY TOWARD THE CURRENT SOUTHWARD CONSENSUS.
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
AFTER SOME LINGERING LIGHT SNOW SHOWERS/FLURRIES DEPART TO THE
EAST THIS EVENING...CLEARING SKIES APPEAR POISED TO MOVE INTO
CENTRAL ILLINOIS. NIGHT TIME MOISTURE/CLOUD TRENDS CAN BE A BIT
TRICKY WITH ADVANCING HIGH PRESSURE...SINCE THE SUBSIDENCE
INVERSION CAN SOMETIMES TRAP LOW LEVEL MOISTURE THAT THE WEAKER
LOW LEVEL WINDS ARE UNABLE TO PUSH OUT. THAT CAN LEAD TO BACK-
BUILDING LOW CLOUDS/STRATUS AT NIGHT...AFTER A STEADY CLEARING
PROGRESS IS EVIDENT BEFORE SUNSET. PILOT REPORTS CONFIRM THE THIN
LAYER OF MOISTURE OF THIS CLOUD DECK...SO THE CLEARING MAY
CONTINUE TONIGHT AS ADVERTISED IN THE MODELS. WE DID SLOW DOWN THE
PROGRESSION IN THE SKY GRIDS...BUT DO EVENTUALLY CLEAR THINGS OUT
IN THE EAST TOWARD MORNING.
THE TIMING OF THE CLEARING CAN HAVE A BIG IMPACT ON LOW
TEMPERATURES...BUT WITH CLEARING EXPECTED IN MOST AREAS BY
MORNING...WE SHOULD BE SEE LOWS DROP BELOW NORMAL ACROSS THE
BOARD...WITH SOME SINGLE DIGIT LOWS NW OF THE IL RIVER.
HIGH PRESSURE WILL PROVIDE SUNNY SKIES AND QUIET CONDITIONS ON
SUNDAY...BUT THE QUICKLY APPROACHING LOW PRESSURE SYSTEM WILL
BRING INCREASING CLOUDS SUNDAY NIGHT.
MONDAY MORNING...SNOW SHOULD BEGIN TO ADVANCE ACROSS OUR CENTRAL
COUNTIES FROM SW TO NE. LOOKING AT THE CONSENSUS MODELS
(ECMWF/GFS/UKMET) IT APPEARS THAT THE MAIN PERIOD OF STEADIER
SNOWS WILL BE MONDAY AFTERNOON AND EVENING...WHERE MOST OF THE
ACCUMULATION WILL OCCUR. SNOWFALL TOTALS UNDER THAT SCENARIO WOULD
RANGE FROM LESS THAN A HALF INCH TOWARD PEORIA...WITH THE ONE INCH
LINE AS FAR NORTH AS A LINE FROM RUSHVILLE TO LINCOLN TO
CHAMPAIGN...1-2" FROM THAT LINE SOUTH TO I-70...AND 2-3" SOUTH OF
I-70.
SOME SNOW SHOWERS MAY LINGER IN THE SOUTHEAST AFTER MIDNIGHT NEW
YEARS EVE...BUT PRECIP SHOULD COME TO AN END BY SUNRISE ON
TUESDAY. CLEARING SKIES ARE EVEN FORECAST FOR THE AFTERNOON AS
HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST. A COLD NIGHT
WILL BE ON TAP TUES NIGHT UNDER CLEAR SKIES AND LIGHT
WINDS...ALONG WITH A FRESH SNOW COVER. LOW TEMPS WOULD LIKELY DROP
BELOW GUIDANCE AND INTO THE SINGLE DIGITS IN MANY AREAS.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
THE EXTENDED PERIOD WILL BE DOMINATED BY COLD AND DRY CONDITIONS
UNDER SURFACE HIGH PRESSURE. THE NORTHERN STEAM STORM TRACK LOOKS
TO REMAIN FARTHER NORTH ACROSS THE GREAT LAKES...AND THE SOUTHERN
STREAM REMAINS SOUTH...PUSHING STORM SYSTEMS ACROSS THE GULF
COAST. WE WILL KEEP HIGHS AND LOWS BELOW NORMAL...WITH THE COLDEST
NIGHT LOOKING LIKE THURSDAY NIGHT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
328 PM EST SUN DEC 30 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 242 PM EST SUN DEC 30 2012
A COLD FRONT AND UPPER TROUGH WILL MOVE INTO THE AREA ON MONDAY
BEFORE EXITING ON TUESDAY. THIS WILL BRING ANOTHER ROUND OF LIGHT
SNOW TO CENTRAL INDIANA. FOR WEDNESDAY INTO NEXT WEEKEND...COLD
AND DRY WEATHER WILL BE THE RULE.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 242 PM EST SUN DEC 30 2012
TEMPERATURES WILL BE TRICKY TONIGHT. MAINLY SOME HIGH CLOUDS EARLY
THIS EVENING...WITH SOUTHWEST WINDS. TEMPERATURES MAY FALL FOR A
WHILE THIS EVENING BEFORE LEVELING OUT OR RISING OVERNIGHT AS WARM
ADVECTION KICKS IN.
QUESTION BECOMES HOW FAR WILL TEMPERATURES FALL BEFORE LEVELING
OFF. FEEL THAT WITH THE SOUTHWEST WINDS STAYING UP TEMPERATURES
WILL NOT PLUMMET. DID ALLOW READINGS TO REACH 20-25...WHICH IS
COOLER THAN THE MET BUT CLOSE TO THE MAV.
CLOUDS WILL INCREASE AS ISENTROPIC LIFT CONTINUES IN THE WARM
ADVECTION TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 242 PM EST SUN DEC 30 2012
FOCUS IS ON PRECIPITATION EVENT MONDAY INTO TUESDAY. MODELS ARE
ACTUALLY NOT THAT FAR FROM EACH OTHER...SO USED A BLEND FOR THE
MOST PART.
FORCING WILL INCREASE DURING THE DAY ON MONDAY AS COLD FRONT
APPROACHES. FIRST ROUND WITH ISENTROPIC LIFT WILL MAINLY IMPACT
THE AREA AFTER 18Z. GRADUALLY INCREASED POPS DURING THE
MORNING...FINALLY REACHING LIKELY CATEGORY DURING THE AFTERNOON
ALL AREAS. SOUNDINGS SHOW THAT ENTIRE ATMOSPHERE SHOULD REMAIN
BELOW FREEZING...WITH TEMPERATURES NEAR THE SURFACE AROUND
FREEZING. THUS PRECIPITATION SHOULD REMAIN AS SNOW.
BEST FORCING MONDAY AFTERNOON LOOKS TO BE IN THE NORTHERN FORECAST
AREA...SO WENT WITH AROUND AN INCH THERE. WENT LESS THAN AN INCH
SOUTH.
ANOTHER ROUND OF FORCING MOVES THROUGH MONDAY NIGHT...MAINLY
IMPACTING THE SOUTHERN FORECAST AREA. THUS WENT LIKELY POPS ACROSS
THE SOUTH HALF AND CHANCE POPS ACROSS THE NORTH. LOOKS LIKE AN
INCH POSSIBLE SOUTH WITH LESSER AMOUNTS NORTH.
GIVEN THE ABOVE ENDED UP WITH A STORM TOTAL OF 1-2 INCHES ACROSS
THE ENTIRE FORECAST AREA. WILL HAVE TO KEEP AN EYE ON HOW THIS
DEVELOPS THOUGH AS MODELS ARE HINTING AND SOME AREAS OF
FRONTOGENETICAL FORCING AND DECENT LIFT IN THE SNOW GROWTH LAYER
BOTH IN THE AFTERNOON AND AGAIN IN THE EVENING. THIS COULD LEAD TO
BANDS OF HIGHER AMOUNTS...PERHAPS REACHING INTO ADVISORY CRITERIA.
WILL CONTINUE TO MONITOR. WILL ISSUE A SPS TO HIGHLIGHT THE UPCOMING
SNOW.
KEPT LOW POPS TUESDAY MORNING AS THE FRONT EXITS...BUT TUESDAY
AFTERNOON NOW LOOKS DRY. HIGH PRESSURE WILL MOVE IN AND PROVIDE
DRY AND COLD WEATHER FOR TUESDAY NIGHT AND WEDNESDAY.
FOR TEMPERATURES...TRENDED TOWARD THE COOLER OF THE GUIDANCE WITH
SNOW ON THE GROUND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 242 PM EST SUN DEC 30 2012
RATHER UNEVENTFUL LONG TERM PORTION WITH COLD HIGH PRESSURE
DOMINATING OUR WEATHER MOST OF THE PERIOD. MODELS INDICATE AN UPPER
TROUGH WILL BE MOVING BY AROUND THURSDAY NIGHT AND THERE MAY BE VERY
LOW CHANCES OF A FEW SNOW SHOWERS OR FLURRIES NORTH. ANOTHER WEAK
SYSTEM WILL BE MOVING THROUGH LATE DAY 6 AND DAY 7. AGAIN WE ARE
TALKING NO MORE THAN A FEW FLURRIES IF ANYTHING. HPC...ALL BLEND
AND CONSALL POPS ARE DRY. SEE NO REASON AT THIS TIME FROM DEVIATING
FROM THOSE NUMBERS THAT FAR OUT. THUS WILL KEEP LONG TERM PERIOD
DRY FOR NOW.
WENT A FEW DEGREES COLDER SOME PERIODS AS THERE SHOULD BE SOME SNOW
COVER THROUGHOUT THE EXTENDED. OTHERWISE...ONLY MINOR CHANGES MADE
TO ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 30/21Z IND TAF UPDATE/...
ISSUED AT 328 PM EST SUN DEC 30 2012
ONLY MADE MINOR TWEAK TO INCREASE CIRRUS.
PREVIOUS DISCUSSION FOLLOWS...
VFR THROUGH THE NEXT 24 HOURS...THEN MVFR OR IFR SNOW POSSIBLE LATE
MONDAY AFTERNOON.
HIGH PRESSURE WILL MOVE EAST ACROSS THE OHIO VALLEY THIS AFTERNOON.
MODEL SOUNDINGS INDICATE MAINLY INCREASING HIGH CLOUDS BY THIS
EVENING FOLLOWED BY MID CLOUDS LATE TONIGHT AND MONDAY MORNING.
EARLIER SOME MODELS INDICATED COULD BE A FEW POCKETS OF STRATUS
DEVELOPING DUE TO SNOW MELT. SO FAR NO SITES HAVE THIS HAPPENING
AND RUC MODEL HAS TRENDED DRIER IN LOWER LAYERS...SO WILL DROP
MENTION OF SCT015 WHICH WAS IN PREVIOUS TAF.
A COLD FRONT WILL MOVE INTO NORTHERN INDIANA BY MIDDAY MONDAY AND
BOTH GFS AND NAM MODEL INDICATE LIGHT SNOW POSSIBLE BY LATE MONDAY.
THUS WILL ADD A GROUP IN KIND 30 HOUR TAF TO ACCOMMODATE THIS. THIS
IS BEYOND THE TIME OF OTHER CENTRAL INDIANA TAFS.
WINDS WILL BE SOUTHWEST AROUND 8 KNOTS OR LESS THIS AFTERNOON AND
TONIGHT AND SOUTHWEST UP TO 10 KNOTS ON MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....JH
AVIATION...JH/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
242 PM EST SUN DEC 30 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 242 PM EST SUN DEC 30 2012
A COLD FRONT AND UPPER TROUGH WILL MOVE INTO THE AREA ON MONDAY
BEFORE EXITING ON TUESDAY. THIS WILL BRING ANOTHER ROUND OF LIGHT
SNOW TO CENTRAL INDIANA. FOR WEDNESDAY INTO NEXT WEEKEND...COLD
AND DRY WEATHER WILL BE THE RULE.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 242 PM EST SUN DEC 30 2012
TEMPERATURES WILL BE TRICKY TONIGHT. MAINLY SOME HIGH CLOUDS EARLY
THIS EVENING...WITH SOUTHWEST WINDS. TEMPERATURES MAY FALL FOR A
WHILE THIS EVENING BEFORE LEVELING OUT OR RISING OVERNIGHT AS WARM
ADVECTION KICKS IN.
QUESTION BECOMES HOW FAR WILL TEMPERATURES FALL BEFORE LEVELING
OFF. FEEL THAT WITH THE SOUTHWEST WINDS STAYING UP TEMPERATURES
WILL NOT PLUMMET. DID ALLOW READINGS TO REACH 20-25...WHICH IS
COOLER THAN THE MET BUT CLOSE TO THE MAV.
CLOUDS WILL INCREASE AS ISENTROPIC LIFT CONTINUES IN THE WARM
ADVECTION TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 242 PM EST SUN DEC 30 2012
FOCUS IS ON PRECIPITATION EVENT MONDAY INTO TUESDAY. MODELS ARE
ACTUALLY NOT THAT FAR FROM EACH OTHER...SO USED A BLEND FOR THE
MOST PART.
FORCING WILL INCREASE DURING THE DAY ON MONDAY AS COLD FRONT
APPROACHES. FIRST ROUND WITH ISENTROPIC LIFT WILL MAINLY IMPACT
THE AREA AFTER 18Z. GRADUALLY INCREASED POPS DURING THE
MORNING...FINALLY REACHING LIKELY CATEGORY DURING THE AFTERNOON
ALL AREAS. SOUNDINGS SHOW THAT ENTIRE ATMOSPHERE SHOULD REMAIN
BELOW FREEZING...WITH TEMPERATURES NEAR THE SURFACE AROUND
FREEZING. THUS PRECIPITATION SHOULD REMAIN AS SNOW.
BEST FORCING MONDAY AFTERNOON LOOKS TO BE IN THE NORTHERN FORECAST
AREA...SO WENT WITH AROUND AN INCH THERE. WENT LESS THAN AN INCH
SOUTH.
ANOTHER ROUND OF FORCING MOVES THROUGH MONDAY NIGHT...MAINLY
IMPACTING THE SOUTHERN FORECAST AREA. THUS WENT LIKELY POPS ACROSS
THE SOUTH HALF AND CHANCE POPS ACROSS THE NORTH. LOOKS LIKE AN
INCH POSSIBLE SOUTH WITH LESSER AMOUNTS NORTH.
GIVEN THE ABOVE ENDED UP WITH A STORM TOTAL OF 1-2 INCHES ACROSS
THE ENTIRE FORECAST AREA. WILL HAVE TO KEEP AN EYE ON HOW THIS
DEVELOPS THOUGH AS MODELS ARE HINTING AND SOME AREAS OF
FRONTOGENETICAL FORCING AND DECENT LIFT IN THE SNOW GROWTH LAYER
BOTH IN THE AFTERNOON AND AGAIN IN THE EVENING. THIS COULD LEAD TO
BANDS OF HIGHER AMOUNTS...PERHAPS REACHING INTO ADVISORY CRITERIA.
WILL CONTINUE TO MONITOR. WILL ISSUE A SPS TO HIGHLIGHT THE UPCOMING
SNOW.
KEPT LOW POPS TUESDAY MORNING AS THE FRONT EXITS...BUT TUESDAY
AFTERNOON NOW LOOKS DRY. HIGH PRESSURE WILL MOVE IN AND PROVIDE
DRY AND COLD WEATHER FOR TUESDAY NIGHT AND WEDNESDAY.
FOR TEMPERATURES...TRENDED TOWARD THE COOLER OF THE GUIDANCE WITH
SNOW ON THE GROUND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 242 PM EST SUN DEC 30 2012
RATHER UNEVENTFUL LONG TERM PORTION WITH COLD HIGH PRESSURE
DOMINATING OUR WEATHER MOST OF THE PERIOD. MODELS INDICATE AN UPPER
TROUGH WILL BE MOVING BY AROUND THURSDAY NIGHT AND THERE MAY BE VERY
LOW CHANCES OF A FEW SNOW SHOWERS OR FLURRIES NORTH. ANOTHER WEAK
SYSTEM WILL BE MOVING THROUGH LATE DAY 6 AND DAY 7. AGAIN WE ARE
TALKING NO MORE THAN A FEW FLURRIES IF ANYTHING. HPC...ALL BLEND
AND CONSALL POPS ARE DRY. SEE NO REASON AT THIS TIME FROM DEVIATING
FROM THOSE NUMBERS THAT FAR OUT. THUS WILL KEEP LONG TERM PERIOD
DRY FOR NOW.
WENT A FEW DEGREES COLDER SOME PERIODS AS THERE SHOULD BE SOME SNOW
COVER THROUGHOUT THE EXTENDED. OTHERWISE...ONLY MINOR CHANGES MADE
TO ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 30/18Z TAF ISSUANCE/...
ISSUED AT 1208 PM EST SUN DEC 30 2012
VFR THROUGH THE NEXT 24 HOURS...THEN MVFR OR IFR SNOW POSSIBLE LATE
MONDAY AFTERNOON.
HIGH PRESSURE WILL MOVE EAST ACROSS THE OHIO VALLEY THIS AFTERNOON.
MODEL SOUNDINGS INDICATE MAINLY INCREASING HIGH CLOUDS BY THIS
EVENING FOLLOWED BY MID CLOUDS LATE TONIGHT AND MONDAY MORNING.
EARLIER SOME MODELS INDICATED COULD BE A FEW POCKETS OF STRATUS
DEVELOPING DUE TO SNOW MELT. SO FAR NO SITES HAVE THIS HAPPENING
AND RUC MODEL HAS TRENDED DRIER IN LOWER LAYERS...SO WILL DROP
MENTION OF SCT015 WHICH WAS IN PREVIOUS TAF.
A COLD FRONT WILL MOVE INTO NORTHERN INDIANA BY MIDDAY MONDAY AND
BOTH GFS AND NAM MODEL INDICATE LIGHT SNOW POSSIBLE BY LATE MONDAY.
THUS WILL ADD A GROUP IN KIND 30 HOUR TAF TO ACCOMMODATE THIS. THIS
IS BEYOND THE TIME OF OTHER CENTRAL INDIANA TAFS.
WINDS WILL BE SOUTHWEST AROUND 8 KNOTS OR LESS THIS AFTERNOON AND
TONIGHT AND SOUTHWEST UP TO 10 KNOTS ON MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....JH
AVIATION...JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1208 PM EST SUN DEC 30 2012
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 319 AM EST SUN DEC 30 2012
HIGH PRESSURE WILL BUILD IN TODAY...BUT ANOTHER COLD FRONT WILL
BRING SNOW CHANCES BACK INTO THE FORECAST FOR MONDAY INTO TUESDAY.
COLD AND DRY WEATHER WILL END THE WORK WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1007 AM EST SUN DEC 30 2012
ADJUSTED HOURLY GRIDS TO REFLECT CURRENT TRENDS. FREEZING FOG SHOULD
LIFT SOON ACROSS THE FAR SOUTHERN FORECAST AREA DUE TO THE SUN
BURNING IT OFF. THERE AND OTHER AREAS WHERE IT CLEARED OVERNIGHT
SHOULD SEE TEMPERATURES REBOUND RELATIVELY QUICKLY WITH THE SUN.
DID LOWER MAX TEMPERATURES A BIT IN THE SOUTH WHERE THEY STARTED OUT
VERY COLD. OTHERWISE LEFT HIGHS ALONE WITH THE SUNSHINE EXPECTED
TODAY.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 319 AM EST SUN DEC 30 2012
FORECAST FOCUS IS ON PRECIPITATION CHANCES MONDAY INTO TUESDAY.
CLOUDS WILL INCREASE TONIGHT AS ISENTROPIC LIFT BEGINS AHEAD OF
THE FRONT. WENT SLIGHTLY ABOVE MOS TO ACCOUNT FOR INCREASING
CLOUDINESS.
FRONT MOVES IN ON MONDAY AND MONDAY NIGHT WITH ASSOCIATED UPPER
TROUGH AND CHANCES FOR PRECIPITATION WILL INCREASE. TRENDS CONTINUE
TO DEPICT BEST MOISTURE AND FORCING ACROSS THE SOUTHERN FORECAST
AREA AND THIS IS WHERE THE HIGHEST POPS (LIKELY) EXIST.
PRECIPITATION TYPE DOES NOT LOOK TO BE AN ISSUE THIS FAR NORTH AND
IS EXPECTED TO FALL IN ONLY THE FORM OF SNOW.
AS WITH THE EVENT ON FRIDAY NIGHT...AM A LITTLE CONCERNED AT THE
STRONG FRONTOGENIC FORCING AT 500H WHICH COULD PUSH SNOWFALL AMOUNTS
HIGHER THAN THE 1 TO 2 INCHES THE MODELS ARE PREDICTING. BUMPED UP
SNOWFALL AMOUNTS ACROSS THE ENTIRE CWA...FOR 2 TO 4 ACROSS THE FAR
SOUTH...1-3 ACROSS THE CENTER AND 1 TO 2 FOR THE NORTHERN
COUNTIES. THE SOUTHERN COUNTIES (THOSE SOUTH OF THE I-70 CORRIDOR)
ARE COMING CLOSE TO ADVISORY CRITERIA. PER COORDINATION WITH
SURROUNDING OFFICES WILL HOLD OFF ON ISSUING ONE NOW AND ISSUE AN
SPS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 241 AM EST SUN DEC 30 2012
RATHER UNEVENTFUL LONG TERM PORTION OF THE FORECAST WITH COLD
SURFACE HIGH PRESSURE IN CONTROL FOR MOST OF THE PERIOD. MODELS DO
INDICATE A WEAKENING UPPER LEVEL DISTURBANCE LATE IN THE WEEK THAT
MAY BE ABLE TO PRODUCE FLURRIES...BUT NO POINT IN MESSING WITH A
TRACE EVENT 5-6 DAYS OUT.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGHOUT...AS MUCH AS
10-12 DEGREES BELOW NORMAL AT TIMES. ALLBLEND HANDLED THIS WELL
WITH FEW TWEAKS REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 30/18Z TAF ISSUANCE/...
ISSUED AT 1208 PM EST SUN DEC 30 2012
VFR THROUGH THE NEXT 24 HOURS...THEN MVFR OR IFR SNOW POSSIBLE LATE
MONDAY AFTERNOON.
HIGH PRESSURE WILL MOVE EAST ACROSS THE OHIO VALLEY THIS AFTERNOON.
MODEL SOUNDINGS INDICATE MAINLY INCREASING HIGH CLOUDS BY THIS
EVENING FOLLOWED BY MID CLOUDS LATE TONIGHT AND MONDAY MORNING.
EARLIER SOME MODELS INDICATED COULD BE A FEW POCKETS OF STRATUS
DEVELOPING DUE TO SNOW MELT. SO FAR NO SITES HAVE THIS HAPPENING
AND RUC MODEL HAS TRENDED DRIER IN LOWER LAYERS...SO WILL DROP
MENTION OF SCT015 WHICH WAS IN PREVIOUS TAF.
A COLD FRONT WILL MOVE INTO NORTHERN INDIANA BY MIDDAY MONDAY AND
BOTH GFS AND NAM MODEL INDICATE LIGHT SNOW POSSIBLE BY LATE MONDAY.
THUS WILL ADD A GROUP IN KIND 30 HOUR TAF TO ACCOMMODATE THIS. THIS
IS BEYOND THE TIME OF OTHER CENTRAL INDIANA TAFS.
WINDS WILL BE SOUTHWEST AROUND 8 KNOTS OR LESS THIS AFTERNOON AND
TONIGHT AND SOUTHWEST UP TO 10 KNOTS ON MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...50
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...JH
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1144 PM CST SAT DEC 29 2012
.AVIATION...
STRATUS WITH LIFR TO IFR CIGS OVER NORTH CENTRAL INTO NORTHEAST
IOWA NOT BEING WELL HANDLED BY MODELS EXCEPT FOR THE RAP MODEL
WHICH HAS IDEA OF THE CLOUDS BUT WAY OVERDONE ON EXTENT. RECENT
SATELLITE LOOPS SHOWS THE CLOUDS MOVING E/ESE... WHICH PUTS THEM
ON TRAJECTORY TO IMPACT AT LEAST KDBQ OVERNIGHT INTO SUNDAY
MORNING WITH PERIOD OF IFR TO LIFR CIGS ALONG WITH FOG. CANT RULE
OUT EVEN A PERIOD OF DENSE FOG AT KDBQ TOWARD DAYBREAK AS WELL
BUT LOW CONFIDENCE TO INCLUDE ATTIM. SOME CONCERN THAT IFR TO
LIFR CIGS MAY PROPAGATE AND/OR DEVELOP FURTHER SOUTH TO KCID AND
KMLI TERMINALS LATE TONIGHT INTO SUNDAY MORNING BASED ON THE LOW
LEVEL WIND FIELDS FROM W/NW. HOWEVER... LOW CONFIDENCE PRECLUDES
ANY INCLUSION OF LOW CIGS AT KCID AND KMLI ATTIM AND PASS TO NEXT
SHIFT TO MONITOR. HAVE KEPT MENTION OF BR WITH VSBYS 2-5SM AT
KCID...KMLI AND KBRL THROUGH DAYBREAK. ANY LOW CLOUDS AND FOG
LIKELY TO DISSIPATE WITH VFR CONDITIONS AT ALL SITES BY LATE
MORNING INTO EARLY AFTERNOON WITH SOUTHERLY WINDS INCREASING TO
AROUND 10 KTS. OCCASIONAL GUSTS OF 15-18 KTS POSSIBLE AT TIMES
IN THE AFTERNOON. COLD FRONT TO APPROACH SUNDAY EVENING WITH WINDS
SHIFTING TO THE SOUTHWEST AROUND 10 KTS.
&&
.PREV DISCUSSION... /ISSUED 916 PM CST SAT DEC 29 2012/
UPDATE...
LOW CLOUDS EXITING FAR EAST SECTIONS ATTIM... WITH ATTENTION NOW
SHIFTING TO COUPLE OF AREAS OF LOW CLOUDS TO OUR N/NW. THE
LOW CLOUDS OVER MN INTO WI ARE ON BACK SIDE OF DEPARTING TROUGH.
MEANWHILE... SMALL AREA OF LOW CLOUDS OVER NW INTO NCTRL IA APPEARS
ATTENDANT TO ZONE OF LOW LEVEL WARM ADVECTION. MOST MODELS NOT
HANDLING THESE CLOUDS WELL EXCEPT RAP MODEL BUT IT IS OVERDONE WITH
EXTENT. LAST 60 MINS OF 11-3.9 MICRON SATELLITE LOOP SHOW LOW CLOUDS
MOVING NEARLY DUE EAST TO EVEN SLIGHTLY SOUTH OF EAST. THIS IS IN
LINE WITH LOW LEVEL WIND FIELDS WHICH ARE ROUGHLY FROM WNW OR ROUGHLY
280-290 DEGREES. ON THIS TRAJECTORY WOULD EXPECT SOME OF THESE LOW
CLOUDS TO MAKE IT INTO AT LEAST THE FAR NORTHERN CWA LATE EVE AND
OVRNGT. AS RESULT... WILL BE SENDING UPDATE TO INCREASE CLOUD COVER
MAINLY ALONG AND NORTH OF HWY 20. CANT RULE OUT DEVELOPMENT OR
PROPAGATION TO BRING LOW CLOUD DECK FARTHER SOUTH TOWARDS KCID TO
KSQI LINE... BUT WILL HOLD ON INCREASING CLOUDS THAT FAR SOUTH FOR
NOW AND CONTINUE TO MONITOR TRENDS. WITH THE LOW CLOUDS ALSO EXPECTING
SOME FLURRIES AS SEEN IN OBS. AS CLOUD TRENDS GO... SO GO THE TEMPS.
FOR NOW MADE FEW CHGS TO MINS NORTH WITH PROGRESSIVE NATURE OF THE
CLOUDS. ELSEWHERE... HAVE TRIMMED LOWS BY COUPLE DEGS IN MANY AREAS
WITH GENERALLY CLEAR SKIES.
PREV DISCUSSION... /ISSUED 307 PM CST SAT DEC 29 2012/
SYNOPSIS...
THE MORNING UA ANALYSIS SHOWED AN UPPER TROF OVER THE CENTRAL U.S.
THE MAIN TROF AXIS EXTENDED FROM LAKE MICHIGAN THROUGH THE LOWER
OHIO VALLEY WITH A SECONDARY SHORT WAVE OVER WESTERN IOWA. AT THE
SURFACE THE REGION WAS UNDER CYCLONIC FLOW ASSOCIATED WITH LOW
PRESSURE OFF THE MID ATLANTIC COAST. WIDESPREAD LOW CLOUDS OVER THE
AREA THIS MORNING WERE ACCOMPANIED BY SOME LIGHT SNOW. THE CLOUDS
HAVE BEEN STEADILY CLEARING FROM WEST TO EAST THROUGH EARLY THIS
AFTERNOON.
SHORT TERM...TONIGHT AND SUNDAY...
EXTRAPOLATION OF THE CLEARING LINE HAS THE BACK EDGE OF THE LOW
CLOUDS EAST OF THE CWFA BY 03Z. THIS LOOKS REASONABLE...EXCEPT FOR
NORTHWEST ILLINOIS WHERE MODEL PROGS HOLD HIGHER VALUES OF LOW LEVEL
RH THROUGH MIDNIGHT AS THE LOW LEVEL RIDGE BUILDS INTO THAT AREA
FIRST. HAVE SET THE GRIDS UP FOR A FASTER CLEARING TREND OVER THE
SOUTHWEST HALF OF THE AREA THIS EVENING AND A LITTLE SLOWER TREND IN
THE NORTHEAST. THERE IS ALSO SOME CONCERN FOR STRATUS AND FOG
DEVELOPING JUST EAST OF THE RIDGE AXIS LATE TONIGHT...SIMILAR TO
WHAT HAPPENED IN EASTERN SOUTH DAKOTA THIS MORNING. THE RAP AND NAM
5KM RH PROGS WERE HINTING AT THIS OCCURRING OVER EASTERN IA AFTER
MIDNIGHT. WHILE THIS CANNOT BE RULED OUT...THERE IS NOT ENOUGH
CONFIDENCE IN ITS OCCURRENCE TO INCLUDE IN THE FORECAST JUST YET.
CLEARING SKIES AND LIGHT WINDS TONIGHT SHOULD ALLOW FOR GOOD
RADIATIONAL COOLING WITH LOWS JUST BELOW ZERO NORTHWEST TO AROUND
10 IN THE SOUTHEAST. THE SURFACE RIDGE AXIS WILL BE EAST OF THE
AREA BY 12Z SUNDAY WITH SOUTH WINDS INCREASING DURING THE DAY AS THE
RIDGE CONTINUES TO MOVE EAST AND A COLD FRONT MOVES INTO NORTHWEST
IOWA. HIGH CLOUDS WILL ALSO BE ON THE INCREASE. TEMPERATURES WILL
BE A CHALLENGE TOMORROW WITH MODELS SHOWING A SHALLOW BUT STRONG
INVERSION OVER THE AREA. HIGHS IN THE MID 20S NORTH TO LOW 30S SOUTH
WERE BASED ON THE SHALLOW MIXING. IF WINDS ARE STRONGER THAN
FORECAST THEN...MIXING WILL BE DEEPER AND THE FORECAST HIGHS WILL BE
ON THE COLD SIDE. DLF
LONG TERM...MONDAY THROUGH SATURDAY
TWO MAIN CONCERNS IN THIS TIME FRAME ARE THE WEAK CYCLOGENESIS
EVENT WHICH COULD BRING PRECIP TO THE SOUTH LATE MONDAY AND EARLY
TUESDAY...AND THE MUDDLE AMONGST THE MODELS WITH THE UPPER AIR
PATTERN AND SUBSEQUENT DETAILS MIDWEEK.
REGARDING THE MONDAY EVENT...THE NAM IS MORE VIGOROUS AND FURTHER
NORTH WITH DEVELOPING THE LOW THAN THE GFS AND ECMWF...WHICH ARE
WEAKER AND FURTHER SOUTH. HAVE SHADED POPS TO FAVOR THE GFS/ECMWF
SOLUTIONS AND KEPT QPF/SNOW ON THE LIGHT SIDE.
AT MID WEEK...THE EXTENDED MODELS ARE INCONSISTENT AMONG
THEMSELVES AND FROM RUN TO RUN IN HANDLING THE COMPLEX SPLIT FLOW
PATTERN WHICH INCLUDES A SOUTHWEST U.S. CUTOFF AND AN ACTIVE
NORTHERN STREAM. THE 12Z ECMWF MOVES A CLIPPER SYSTEM TO OUR
NORTHEAST WEDNESDAY-THURSDAY...WHICH IS FURTHER NORTH AND EAST AT
THAN AT 00Z WHEN IT WAS PROGGED OVER OUR AREA. MEANWHILE...THE
12Z GFS PROGS THIS CLIPPER SYSTEM FASTER AND EVEN FURTHER
NORTHEAST...SO IT APPEARS THIS WOULD BE A NONEVENT FOR US.
THE GFS DOES HOLD MORE ENERGY BACK OVER THE NORTHERN ROCKIES WHICH
EVENTUALLY CUTS OFF AND DRIFTS ACROSS THE CENTRAL U.S. THROUGH
THE WEEKEND. HOWEVER...THIS GFS RUN IS AN OUTLIER RELATIVE TO THE 00Z
ENSEMBLE MEAN.
THUS FAITH IN ANY OF THESE SOLUTIONS IS LOW. HOWEVER...THE COMMON
THEME IS THAT TROUGHINESS DEVELOPS AND PROGRESSES THROUGH THE
CENTRAL U.S. LATE NEXT WEEK. THERE APPEARS TO BE NO SIGNIFICANT
PRECIP EVENT IN THIS TIME FRAME...AND INDICATIONS ARE THAT
REENFORCING COLD AIR MIGHT GIVE US OUR COLDEST TEMPS SO FAR THIS
SEASON SOMETIME LATE NEXT WEEK INTO THE WEEKEND. WOLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
731 PM CST MON DEC 31 2012
.UPDATE...
ISSUED AT 731 PM CST MON DEC 31 2012
WINTER WEATHER EVENT IS MOVING ALONG QUICKLY. FORECAST SOUNDINGS
FROM BOTH THE RAP AND THE NAM SUGGEST THAT DRY AIR WILL MOVE INTO
OUR REGION AT THE MID LEVELS OF THE ATMOSPHERE. THIS WOULD SUGGEST
THAT CRYSTALS NEEDED FOR SNOW WILL BEGIN TO DIMINISH.
HOWEVER...COLDER AIR SHOULD FILTER IN AS THE FRONT NOW EXTENDING
FROM CMI TO SGF MOVES SOUTH.
THIS WOULD RESULT IN MORE OF A FREEZING RAIN/DRIZZLE EVENT. WILL
NOT TOTALLY REMOVE SNOW AND SLEET AS IT IS A CLOSE CALL AND SOME
SEEDER-FEEDER MECHANISMS MAY BE AVAILABLE AFTER MIDNIGHT.
WILL MAKE SOME ADJUSTMENTS TO THE GRIDS BUT PREVIOUS TRENDS LOOK
GOOD. NO CHANGE TO WINTER WEATHER ADVISORY.
UPDATE ISSUED AT 530 PM CST MON DEC 31 2012
AVIATION DISCUSSION FOR 00Z MONDAY TAF ISSUANCE.
UPDATE TO SHORT TERM
ISSUED AT 541 PM CST MON DEC 31 2012
UPDATED GRIDS THROUGH 4Z AND REMOVED MENTION OF FREEZING RAIN AS
TEMPS SHOULD STAY ABOVE FREEZING THROUGH THAT PERIOD. COLDER AIR
WILL START TO MOVE SOUTH INTO THE AREA AROUND 05Z. FREEZING RAIN
IS STILL QUESTIONABLE...BUT WE ARE GETTING REPORTS OF SLEET...RAIN
AND SNOW.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 150 PM CST MON DEC 31 2012
LIGHT RAINS SPREADING NE FROM ARKANSAS AND MISSOURI...MAYBE A LITTLE
SLEET AT ONSET INTO WEST KENTUCKY GIVEN T/TD SPREADS. ANOTHER AREA
OF LIGHT SNOW WILL MOVE ACROSS SOUTHERN IL AND ACROSS THE EVV TRI-
STATE REGION THROUGH THE AFTERNOON. WITH TEMPS RUNNING 34 TO 37 DO
NOT ANTICIPATE SIGNIFICANT ACCUMULATIONS. BUT MINOR AMOUNTS
CERTAINLY POSSIBLE. BEST CHANCE POPS TONIGHT WILL BE ACROSS THE
SOUTH WHERE PRECIP SHOULD BE LIQUID. LIGHT AMOUNTS EXPECTED ACROSS
THE ADVISORY AREA WITH MIXED PRECIP POTENTIAL STILL IN PLAY. WILL
WATCH OVERNIGHT TEMP TRENDS. CONCERN IS...AS COLDER AIR WORKS
SOUTH AND TEMPS FALL TO OR JUST BELOW FREEZING...THERE COULD BE
SOME VERY LIGHT ICING. THEREFORE WILL MAINTAIN THE ONGOING WINTER
WEATHER ADVISORY AS IS.
SHOULD DRY OUT TUESDAY WITH DECREASING CLOUDS LATE FROM NORTHWEST
TO SOUTHWEST. QUIET WEATHER TUESDAY NIGHT THROUGH WEDNESDAY NIGHT
WITH HIGH PRESSURE IN CONTROL. UNDERCUT GUIDANCE IN SNOW COVER
AREAS AFTER TONIGHT. OTHERWISE MIX OF NAM/GFS AND ECS MOS USED.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 150 PM CST MON DEC 31 2012
DRY AND COLD CONDITIONS WILL PREVAIL THROUGHOUT THE EXTENDED PORTION
OF THE FORECAST WITH SOME MODERATION IN TEMPERATURES SATURDAY
THROUGH MONDAY. A PRONOUNCED 500MB LONG WAVE TROUGH SWINGS SE ACROSS
THE FA THURSDAY AFTERNOON AND EVENING. HOWEVER THIS SYSTEM IS
MOISTURE STARVED AND THEREFORE EXPECT NO MORE THAN SOME INCREASE IN
CLOUDS DURING ITS PASSAGE. AT THE SURFACE A COLD FRONT WILL BRING A
REINFORCING SHOT OF COLD AIR WITH THURSDAY NIGHT BEING THE COLDEST
OF THE EXTENDED PERIOD FOLLOWED CLOSELY IN LOW TEMP VALUES BY FRIDAY
NIGHT.
THE PROGRESSIVE PATTERN WILL CONTINUE WITH ANOTHER MOISTURE STARVED
500MB TROUGH SWINGING SE ACROSS THE FA SATURDAY NIGHT. THIS WILL
HAVE HARDLY ANY IMPACT OTHER THAN SOME LIMITED CLOUD INCREASE MAINLY
OVER SOUTHWEST INDIANA.
FOLLOWING THE WEEKEND TROUGH 500MB HEIGHTS/THICKNESS VALUES WILL
RISE ALLOWING FOR SOME INCREASE IN TEMPERATURES SUNDAY AND
MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 530 PM CST MON DEC 31 2012
CEILINGS WILL LOWER RAPIDLY THIS EVENING AS PRECIPITATION
CONTINUES TO SPREAD EAST ACROSS ALL TAF SITE LOCATIONS. MVFR TO
VFR CEILINGS EARLY WILL FALL TO IFR VALUES AND POSSIBLY EVEN INTO
THE LOW IFR RANGE FOR A FEW HOURS FROM ABOUT 06Z-12Z. VISIBILITIES
WILL ALSO LOWER WITH 2-4SM VALUES COMMON AFTER ABOUT 04Z BEFORE
IMPROVING DURING THE MID TO LATE MORNING TUESDAY. PRECIPITATION
TYPE INCLUDES MAINLY SNOW AT KEVV, RAIN, SLEET AND SNOW AT KCGI
AND KOWB AND RAIN AT KPAH. WINDS WILL BE CALM TO LIGHT SOUTHERLY
THIS EVENING BEFORE BECOMING NORTHERLY BEHIND A COLD FRONT AROUND
MIDNIGHT OR SHORTLY THEREAFTER BEGINNING AT KEVV.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR ILZ075>078-
080>088.
MO...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MOZ076-086-
087-100-107.
IN...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR INZ081-082-
085>088.
KY...NONE.
&&
$$
UPDATE...PS
AVIATION...RS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
802 AM EST SUN DEC 30 2012
.SYNOPSIS...
BRISK WESTERLY WINDS WILL PROVIDE COLD TEMPERATURES
ACROSS THE UPPER OHIO VALLEY WITH SCATTERED SNOW SHOWERS ENDING BY
AFTERNOON EXCEPT PERHAPS NEAR THE MOUNTAINS. PASSING HIGH PRESSURE
WILL PROMOTE DRY CONDITIONS TONIGHT AND MONDAY MORNING. THEN AN
EASTBOUND COLD FRONT WILL BRING IN SNOW SHOWERS FOR THE NEW YEAR.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REGIONAL RADAR MOSAIC ILLUSTRATES SHSN DROPPING SE FROM LAKE ERIE.
VSBYS ARE MAINLY ABOVE 2SM IN THE HEAVIEST SNOW SHOWERS...SO ACCUMULATING
SNOW IS OVER WITH SAVE FOR THE RIDGES THAT ARE UNDER A
WARNING...WHERE ANOTHER INCH OR TWO OF DAYTIME ACCUMULATION MAY
OCCUR.
LATEST RAP ANALYSIS HAS H8 THERMAL TROUGH LIFTING BY 21Z ALLOWING
FOR WINDS TO BECOME SOUTHWEST SHUTTING OFF THE LAKE EFFECT AND
TERRAIN INDUCED SNOWFALL. STILL ANTICIPATE TO SEE SUNSHINE LATER
THIS AFTERNOON FOR AREAS WEST OF I-79 AS THE COLUMN DRIES OUT AND
WAA ENSUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
BUILDING HIGH PRESSURE IS THEN FORECAST TO DRY THE WEATHER INTO
MONDAY...ALTHOUGH TEMPERATURES WILL REMAIN COLDER THAN SEASONAL
AVERAGES.
MOISTURE STREAM VIA SW FLOW ALOFT WL INTERACT WITH AN ADVNG
TROF/FRONTAL SYSTEM LATER ON MONDAY AND INTO TUESDAY FOR THE NEXT
CHC OF PCPN. ALTHOUGH MDL DEPICTIONS DIFFER...HAVE UPPED PRECIP
PROBABILITIES TO THE LIKELY CATEGORY FOR THIS SCENARIO IN
COLLABORATION WITH THE NEIGHBORING OFFICES. CURRENTLY...THE
ACCUMULATION POTENTIAL DOES NOT LOOK SIGNIFICANT AND FORECAST SNOW
AMOUNTS WL BE IN THE SUB-ADVISORY RANGE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BUILDING HIGH PRES IS PROJECTED TO PRVD A DRY THURSDAY...BUT
MOIST SHRTWVS MOVING THRU SW FLOW ON THE ERN FLANK OF A CNTRL
CONUS SHOULD GENERATE PERIODIC SHSN CHCS FOR WEEKS END.
LONG TERM TEMPS WERE FORECAST AT...OR BELOW THE SEASONAL NORMS
USING TWEAKED HPC GUIDANCE.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
WIDESPREAD MVFR CIGS WITH VFR VSBYS ARE THE DOMINANT THEME THRU
EARLY AFTN. VIS COULD DROP TO MVFR IN A SHSN ESP AT FKL/DUJ...BUT
THERE IS AN IMPROVING TREND AS WINDS SHIFT SW ENDING LAKE EFFECT
SNOW SHOWERS. LOW LEVEL MOISTURE EXITS FROM W TO E AFT 20Z ALLOWING
VFR TO RETURN TO ALL TERMINALS BY 0Z.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
IFR RESTRICTIONS ARE LIKELY MONDAY NIGHT INTO TUESDAY. CONDITIONS
IMPROVE TO MVFR WED AND THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ074-076.
WV...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
635 AM EST SUN DEC 30 2012
.SYNOPSIS...
BRISK WESTERLY WINDS WILL PROVIDE COLD TEMPERATURES
ACROSS THE UPPER OHIO VALLEY WITH SCATTERED SNOW SHOWERS ENDING BY
AFTERNOON EXCEPT PERHAPS NEAR THE MOUNTAINS. PASSING HIGH PRESSURE
WILL PROMOTE DRY CONDITIONS TONIGHT AND MONDAY MORNING. THEN AN
EASTBOUND COLD FRONT WILL BRING IN SNOW SHOWERS FOR THE NEW YEAR.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT SATELLITE DATA SHOW CLOUD TOPS WARMING WEST TO EAST ACROSS
THE UPPER OHIO VALLEY AS THE UPPER LEVEL TROUGH EXITS EAST.
CORRESPONDINGLY RADAR DATA SHOWS SNOW SHOWERS ENDING WEST TO EAST
ALTHOUGH STEADY SNOW SHOWERS APPEAR TO BE CONTINUING NEAR THE
WV-MD MOUNTAINS AND PA LAUREL HIGHLANDS...AS BRISK WESTERLY WINDS
ARE PROVIDING OROGRAPHIC LIFT. SO HAVE MAINTAINED WINTER WEATHER
HEADLINES FOR THESE MOUNTAINOUS AREAS.
SURFACE DATA AND RECENT NAM MODEL PROFILES SHOW WINDS CAN GUST TO
30 TO 40 MPH INTO AFTERNOON NEAR THE MOUNTAINS. ELSEWHERE GUSTS
WILL BE UP TO 25 MPH.
FORECASTED THE TEMPERATURE CLIMB TODAY TO BE NO MORE THAN A COUPLE
DEGREES...WHICH IS SUPPORTED BY RECENT GFS LAMP...NAM AND GFS
MOS...AND RAP MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
BUILDING HIGH PRESSURE IS THEN FORECAST TO DRY THE WEATHER INTO
MONDAY...ALTHOUGH TEMPERATURES WILL REMAIN COLDER THAN SEASONAL
AVERAGES.
MOISTURE STREAM VIA SW FLOW ALOFT WL INTERACT WITH AN ADVNG
TROF/FRONTAL SYSTEM LATER ON MONDAY AND INTO TUESDAY FOR THE NEXT
CHC OF PCPN. ALTHOUGH MDL DEPICTIONS DIFFER...HAVE UPPED PRECIP
PROBABILITIES TO THE LIKELY CATEGORY FOR THIS SCENARIO IN
COLLABORATION WITH THE NEIGHBORING OFFICES. CURRENTLY...THE
ACCUMULATION POTENTIAL DOES NOT LOOK SIGNIFICANT AND FORECAST SNOW
AMOUNTS WL BE IN THE SUB-ADVISORY RANGE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BUILDING HIGH PRES IS PROJECTED TO PRVD A DRY THURSDAY...BUT
MOIST SHRTWVS MOVING THRU SW FLOW ON THE ERN FLANK OF A CNTRL
CONUS SHOULD GENERATE PERIODIC SHSN CHCS FOR WEEKS END.
LONG TERM TEMPS WERE FORECAST AT...OR BELOW THE SEASONAL NORMS
USING TWEAKED HPC GUIDANCE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
WIDESPREAD MVFR CIGS WITH VFR VSBYS ARE THE DOMINANT THEME THRU
EARLY AFTN. VIS COULD DROP TO MVFR IN A SHSN ESP AT FKL/DUJ...BUT
THERE IS AN IMPROVING TREND AS WINDS SHIFT SW ENDING LAKE EFFECT
SNOW SHOWERS. LOW LEVEL MOISTURE EXITS FROM W TO E AFT 20Z ALLOWING
VFR TO RETURN TO ALL TERMINALS BY 0Z.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
IFR RESTRICTIONS ARE LIKELY MONDAY NIGHT INTO TUESDAY. CONDITIONS
IMPROVE TO MVFR WED AND THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ074-076.
WV...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023-
041.
&&
$$
AVIATION...98
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
516 AM EST SUN DEC 30 2012
.SYNOPSIS...BRISK WESTERLY WINDS WILL PROVIDE COLD TEMPERATURES
ACROSS THE UPPER OHIO VALLEY WITH SCATTERED SNOW SHOWERS ENDING BY
AFTERNOON EXCEPT PERHAPS NEAR THE MOUNTAINS. PASSING HIGH PRESSURE
WILL PROMOTE DRY CONDITIONS TONIGHT AND MONDAY MORNING. THEN AN
EASTBOUND COLD FRONT WILL BRING IN SNOW SHOWERS FOR THE NEW YEAR.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT SATELLITE DATA SHOW CLOUD TOPS WARMING WEST TO EAST ACROSS
THE UPPER OHIO VALLEY AS THE UPPER LEVEL TROUGH EXITS EAST.
CORRESPONDINGLY RADAR DATA SHOWS SNOW SHOWERS ENDING WEST TO EAST
ALTHOUGH STEADY SNOW SHOWERS APPEAR TO BE CONTINUING NEAR THE
WV-MD MOUNTAINS AND PA LAUREL HIGHLANDS...AS BRISK WESTERLY WINDS
ARE PROVIDING OROGRAPHIC LIFT. SO HAVE MAINTAINED WINTER WEATHER
HEADLINES FOR THESE MOUNTAINOUS AREAS.
SURFACE DATA AND RECENT NAM MODEL PROFILES SHOW WINDS CAN GUST TO
30 TO 40 MPH INTO AFTERNOON NEAR THE MOUNTAINS. ELSEWHERE GUSTS
WILL BE UP TO 25 MPH.
FORECASTED THE TEMPERATURE CLIMB TODAY TO BE NO MORE THAN A COUPLE
DEGREES...WHICH IS SUPPORTED BY RECENT GFS LAMP...NAM AND GFS
MOS...AND RAP MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
BUILDING HIGH PRESSURE IS THEN FORECAST TO DRY THE WEATHER INTO
MONDAY...ALTHOUGH TEMPERATURES WILL REMAIN COLDER THAN SEASONAL
AVERAGES.
MOISTURE STREAM VIA SW FLOW ALOFT WL INTERACT WITH AN ADVNG
TROF/FRONTAL SYSTEM LATER ON MONDAY AND INTO TUESDAY FOR THE NEXT
CHC OF PCPN. ALTHOUGH MDL DEPICTIONS DIFFER...HAVE UPPED PRECIP
PROBABILITIES TO THE LIKELY CATEGORY FOR THIS SCENARIO IN
COLLABORATION WITH THE NEIGHBORING OFFICES. CURRENTLY...THE
ACCUMULATION POTENTIAL DOES NOT LOOK SIGNIFICANT AND FORECAST SNOW
AMOUNTS WL BE IN THE SUB-ADVISORY RANGE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BUILDING HIGH PRES IS PROJECTED TO PRVD A DRY THURSDAY...BUT
MOIST SHRTWVS MOVING THRU SW FLOW ON THE ERN FLANK OF A CNTRL
CONUS SHOULD GENERATE PERIODIC SHSN CHCS FOR WEEKS END.
LONG TERM TEMPS WERE FORECAST AT...OR BELOW THE SEASONAL NORMS
USING TWEAKED HPC GUIDANCE.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
BLEND OF RECENT SURFACE RADAR AND SATELLITE DATA...COUPLED WITH RECENT
RAP NAM AND SREF MODEL OUTPUT PLUS GFS LAMP GUIDANCE...SHOW POST
SYSTEM COLD POOL MVFR STRATOCUMULUS LINGERING ACROSS THE UPPER
OHIO VALLEY INTO AFTERNOON...AND PERHAPS EARLY TONIGHT ACROSS THE
I-80 CORRIDOR.
HOWEVER MOST OF THE INTERMITTENT IFR LIGHT SNOW...ASSOCIATED WITH
AN EASTBOUND UPPER LEVEL TROUGH HAS ENDED. THE IFR LIGHT SNOW
NORTH AND NEAR THE MOUNTAINS SHOULD LIKEWISE END BEFORE 17Z.
HIGH PRESSURE SUBSIDENCE SHOULD PROMOTE WIDESPREAD VFR TONIGHT.
SURFACE WINDS TODAY WILL BE FROM THE WEST AT 12 KTS WITH GUSTS UP
TO 22 KTS. WINDS TONIGHT WILL BE FROM THE SOUTHWEST AT 7 KTS.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
EXPECT VFR THROUGH MONDAY MIDDAY...THEN AN EASTBOUND COLD FRONT
WILL PROVIDE LIGHT SNOW AND IFR RESTRICTIONS LATE MONDAY AND
TUESDAY. POST SYSTEM COLD POOL MAY CAUSE LINGERING MVFR
STRATOCUMULUS WEDNESDAY AND THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ074-076.
WV...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
245 AM EST SUN DEC 30 2012
.SYNOPSIS...
A CROSSING UPPER LEVEL DISTURBANCE WILL SPREAD LIGHT SNOW ACROSS
THE UPPER OHIO VALLEY REGION EARLY THIS MORNING. SIGNIFICANT SNOW
ACCUMULATION WILL BE CONFINED TO THE RIDGES.
&&
.NEAR TERM /THROUGH TODAY/...
NO CHANGES NEEDED FOR THE PREDAWN UPDATE OTHER THAN TO DIMINISH
POPS OVR WRN ZONES AS MID/UPR TROF HAS PROGRESSED FAR ENOUGH EWD
TO END SN SPPRT.
OTHERWISE...SHRTWV TROF WL CONT TO SPREAD LGT SNOW ACRS THE
REGION THIS MRNG. SIGNIFICANT ACCUMULATION WL DEPEND ON UPSLOPE
ENHANCEMENT...HENCE IS CONFINED TO THE RIDGES WHERE THE WINTER
WEATHER ADVISORY FOR FAYETTE AND WESTMO...AND WINTER STORM WARNING
FOR GARRETT...PRESTON...AND TUCKER COUNTIES WILL BE MAINTAINED.
SNOW SHOWER ACTIVITY WILL GRADUALLY DIMINISH...AND CEASE
ALTOGETHER BY MIDDAY AS SBSDNC INCRS...INVERSION LEVELS DROP/MID
LVL COLD POOL WITH THE DISTURBANCE SLIDES EWD.
NEAR TERM TEMPS WERE FORECAST USING A BLEND OF SREF MEANS AND THE
LATEST LAMP GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
BUILDING HIGH PRESSURE IS THEN FORECAST TO DRY THE WEATHER INTO
MONDAY...ALTHOUGH TEMPERATURES WILL REMAIN UNDER THE SEASONAL
AVERAGES.
MOISTURE STREAM VIA SW FLOW ALOFT WL INTERACT WITH AN ADVNG
TROF/FRONTAL SYSTEM LATER ON MONDAY AND INTO TUESDAY FOR THE NEXT
CHC OF PCPN. ALTHOUGH MDL DEPICTIONS DIFFER...HAVE UPPED PRECIP
PROBABILITIES TO THE LIKELY CATEGORY FOR THIS SCENARIO IN
COLLABORATION WITH THE NEIGHBORING OFFICES. CURRENTLY...THE
ACCUMULATION POTENTIAL DOES NOT LOOK SIGNIFICANT AND FORECAST SNOW
AMOUNTS WL BE IN THE SUB-ADVISORY RANGE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BUILDING HIGH PRES IS PROJECTED TO PRVD A DRY THURSDAY...BUT
MOIST SHRTWVS MOVING THRU SW FLOW ON THE ERN FLANK OF A CNTRL
CONUS SHOULD GENERATE PERIODIC SHSN CHCS FOR WEEKS END.
LONG TERM TEMPS WERE FORECAST AT...OR BELOW THE SEASONAL NORMS
USING TWEAKED HPC GUIDANCE.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
BLEND OF RECENT SURFACE RADAR AND SATELLITE DATA SHOW POST SYSTEM COLD
POOL MVFR STRATOCUMULUS LINGERING ACROSS THE UPPER OHIO VALLEY.
INTERMITTENT IFR LIGHT SNOW CONTINUES DUE TO PASSAGE OF AN UPPER
LEVEL TROUGH.
BLEND OF RECENT RAP NAM AND SREF MODEL OUTPUT PLUS GFS LAMP
GUIDANCE SHOW SUBSIDENCE INCREASING ALOFT DUE TO EASTBOUND HIGH
PRESSURE...WHICH WILL VERTICALLY SHRINK THE COLD LAYER UNDERNEATH.
DESPITE THIS SUBSIDENCE...THE COLD POOL MVFR STRATOCUMULUS CAN
LINGER INTO THE AFTERNOON...AND PERHAPS EARLY TONIGHT ACROSS THE
I-80 CORRIDOR. HOWEVER THE INTERMITTENT IFR LIGHT SNOW SHOULD END
BY ABOUT 15Z.
HIGH PRESSURE SUBSIDENCE SHOULD PROMOTE WIDESPREAD VFR TONIGHT.
SURFACE WINDS TODAY WILL BE FROM THE WEST AT 12 KTS WITH GUSTS UP
TO 22 KTS. WINDS TONIGHT WILL BE FROM THE SOUTHWEST AT 7 KTS.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
EXPECT VFR THROUGH MONDAY MIDDAY...THEN AN EASTBOUND COLD FRONT
WILL PROVIDE LIGHT SNOW AND IFR RESTRICTIONS LATE MONDAY AND
TUESDAY. POST SYSTEM COLD POOL MAY CAUSE LINGERING MVFR
STRATOCUMULUS WEDNESDAY AND THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ074-076.
WV...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1254 AM EST SUN DEC 30 2012
.SYNOPSIS...
A CROSSING UPPER LEVEL DISTURBANCE WILL SPREAD LIGHT SNOW ACROSS
THE UPPER OHIO VALLEY REGION EARLY THIS MORNING. SIGNIFICANT SNOW
ACCUMULATION WILL BE CONFINED TO THE RIDGES.
&&
.NEAR TERM /THROUGH TODAY/...
SHRTWV TROF WL CONT TO SPREAD LGT SNOW ACRS THE REGION THIS MRNG. SIGNIFICANT
ACCUMULATION WL DEPEND ON UPSLOPE ENHANCEMENT...HENCE IS CONFINED TO
THE RIDGES WHERE A WINTER WEATHER ADVISORY FOR FAYETTE AND WESTMO...AND
WINTER STORM WARNING FOR GARRETT...PRESTON...AND TUCKER COUNTIES
WILL BE MAINTAINED.
SNOW SHOWER ACTIVITY WILL GRADUALLY DIMINISH...AND CEASE
ALTOGETHER BY MIDDAY AS SBSDNC INCRS...INVERSION LEVELS DROP/MID
LVL COLD POOL WITH THE DISTURBANCE SLIDES EWD.
NEAR TERM TEMPS WERE FORECAST USING A BLEND OF SREF MEANS AND THE
LATEST LAMP GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
BUILDING HIGH PRESSURE IS THEN FORECAST TO DRY THE WEATHER INTO
MONDAY...ALTHOUGH TEMPERATURES WILL REMAIN UNDER THE SEASONAL
AVERAGES.
MOISTURE STREAM VIA SW FLOW ALOFT WL INTERACT WITH AN ADVNG
TROF/FRONTAL SYSTEM LATER ON MONDAY AND INTO TUESDAY FOR THE NEXT
CHC OF PCPN. ALTHOUGH MDL DEPICTIONS DIFFER...HAVE UPPED PRECIP
PROBABILITIES TO THE LIKELY CATEGORY FOR THIS SCENARIO IN
COLLABORATION WITH THE NEIGHBORING OFFICES. CURRENTLY...THE
ACCUMULATION POTENTIAL DOES NOT LOOK SIGNIFICANT AND FORECAST SNOW
AMOUNTS WL BE IN THE SUB-ADVISORY RANGE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BUILDING HIGH PRES IS PROJECTED TO PRVD A DRY THURSDAY...BUT
MOIST SHRTWVS MOVING THRU SW FLOW ON THE ERN FLANK OF A CNTRL
CONUS SHOULD GENERATE PERIODIC SHSN CHCS FOR WEEKS END.
LONG TERM TEMPS WERE FORECAST AT...OR BELOW THE SEASONAL NORMS
USING TWEAKED HPC GUIDANCE.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
BLEND OF RECENT SURFACE RADAR AND SATELLITE DATA SHOW POST SYSTEM COLD
POOL MVFR STRATOCUMULUS LINGERING ACROSS THE UPPER OHIO VALLEY.
INTERMITTENT IFR LIGHT SNOW CONTINUES DUE TO PASSAGE OF AN UPPER
LEVEL TROUGH.
BLEND OF RECENT RAP NAM AND SREF MODEL OUTPUT PLUS GFS LAMP
GUIDANCE SHOW SUBSIDENCE INCREASING ALOFT DUE TO EASTBOUND HIGH
PRESSURE...WHICH WILL VERTICALLY SHRINK THE COLD LAYER UNDERNEATH.
DESPITE THIS SUBSIDENCE...THE COLD POOL MVFR STRATOCUMULUS CAN
LINGER INTO THE AFTERNOON...AND PERHAPS EARLY TONIGHT ACROSS THE
I-80 CORRIDOR. HOWEVER THE INTERMITTENT IFR LIGHT SNOW SHOULD END
BY ABOUT 15Z.
HIGH PRESSURE SUBSIDENCE SHOULD PROMOTE WIDESPREAD VFR TONIGHT.
SURFACE WINDS TODAY WILL BE FROM THE WEST AT 12 KTS WITH GUSTS UP
TO 22 KTS. WINDS TONIGHT WILL BE FROM THE SOUTHWEST AT 7 KTS.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
EXPECT VFR THROUGH MONDAY MIDDAY...THEN AN EASTBOUND COLD FRONT
WILL PROVIDE LIGHT SNOW AND IFR RESTRICTIONS LATE MONDAY AND
TUESDAY. POST SYSTEM COLD POOL MAY CAUSE LINGERING MVFR
STRATOCUMULUS WEDNESDAY AND THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ074-076.
WV...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1212 AM EST SUN DEC 30 2012
.SYNOPSIS...
ISSUED AT 321 PM EST SAT DEC 29 2012
ANOTHER ROUND OF MOSTLY LIGHT SNOW WILL OCCUR OVERNIGHT. UP TO AN
INCH OR TWO OF ACCUMULATION WILL BE POSSIBLE ALONG THE LAKESHORE
NEAR SOUTH HAVEN. AFTER A RATHER DRY SUNDAY AND SUNDAY NIGHT...THE
COMING WORK WEEK WILL BE COLDER THAN NORMAL WITH SLIGHT CHANCES FOR
SNOW MAINLY NEAR THE LAKE SHORE EACH DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 321 PM EST SAT DEC 29 2012
AS NOTED IN THE PREVIOUS FORECAST UPDATE DISCUSSION...WE EXPECT
A SHOT OF LAKE ENHANCED SNOW EARLY TONIGHT MAINLY SOUTH OF HOLLAND.
THE BEST TIMEFRAME LOOKS BETWEEN 10 PM AND 2 AM. MOST RECENT RUNS
OF THE RAP HAVE BACKED TOTAL ACCUMULATIONS AT SOUTH HAVEN DOWN TO AN
INCH OR LESS COMPARED TO EARLIER AMOUNTS OF 2+ INCHES. HOWEVER...
PREFER TO MATCH UP WITH SLIGHTLY HIGHER AMOUNTS ADVERTISED BY IWX TO
ACCOUNT FOR LAKE MOISTURE THAT MAY NOT BE HANDLED WELL BY THE MODELS.
OTHERWISE...FEW CHANGES WERE MADE TO THE FORECAST. DID RAISE POPS
AND SNOW AMOUNTS MONDAY AND MONDAY NIGHT OVER OUR NRN ZONES TO
ACCOUNT FOR COLD FRONT DROPPING SOUTH THROUGH THE AREA AND TO BETTER
MATCH WITH APX TO OUR NORTH.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 321 PM EST SAT DEC 29 2012
THE FOCUS OF THE FORECAST CONTINUES TO BE CENTERED ON THE ARCTIC AIR
MASS THAT IS EXPECTED TO COME DOWN AND THE RESULTING LAKE EFFECT
SNOW SHOWER CHCS.
TUE AND TUE NIGHT LOOK RATHER QUIET. SOME LIGHT LAKE EFFECT WILL BE
POSSIBLE ON TUE AS WE SHOULD SEE A WEAK UPPER TROUGH MOVE BY.
SUFFICIENT INSTABILITY OVER THE LAKE WILL ALSO BE PRESENT WITH H850
TEMPS AROUND -10 TO -12C. THE LAKE EFFECT POTENTIAL WILL DIMINISH
LATE TUE AND MAINLY DRY CONDITIONS ARE EXPECTED TUE NIGHT WITH
RIDGING BUILDING IN.
WE ARE STILL EXPECTING A FAIRLY VIGOROUS UPPER TROUGH TO DROP DOWN
IN THE REGION WED-THU. THIS WILL BRING A THREAT OF SYNOPTIC SNOW
ALONG WITH SOME LAKE ENHANCEMENT/POTENTIAL AS COLDER AIR WILL FOLLOW
IN BEHIND IT. THE MODELS HAVE BEEN STRUGGLING WITH THE EXACT TRACK
WHICH WILL HAVE IMPLICATIONS ON HOW MUCH SNOW FALLS AND WHERE IT
FALLS. THE LATEST MODELS SHOW IT TRACKING NORTH OF THE AREA AND
HAVING MOST OF THE SNOW NORTH OF IT. THE FLOW IS ALSO IMPORTANT DUE
TO LAKE ENHANCEMENT POTENTIAL. FOR NOW WE HAVE A CHC OF SNOW SHOWERS
EVERYWHERE. THIS WILL HAVE TO BE FINE TUNED.
THE NOTEWORTHY CHANGE IN THE MODELS IS A TREND TOWARD A SHORTER STAY
FOR THE ARCTIC AIR. THE MODELS ARE MORE PROGRESSIVE THAN PREVIOUS
RUNS WITH THE UPPER TROUGH AND ARCTIC AIR. THIS IS LIKELY HAVING TO
DO WITH THE SPLIT FLOW THAT DEVELOPS. THE UPPER TROUGH IS EXPECTED
TO BE GONE BY THU NIGHT. THIS WOULD MEAN LESS LAKE EFFECT POTENTIAL.
BY FRI...THE AIR AT H850 IS NOT EVEN COLD ENOUGH FOR LAKE EFFECT. WE
END UP ONCE AGAIN IN NO MANS LAND BETWEEN THE JET STREAMS. THIS
WOULD BRING US SEASONABLE TEMPERATURES WITH LITTLE IF ANY PCPN CHCS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1212 AM EST SUN DEC 30 2012
VARIABLE CONDITIONS CONTINUE ACROSS THE AREA TONIGHT WITH A BAND
OF LAKE EFFECT SNOW SHOWERS MOVING INLAND. THE SNOW SHOWERS ARE
EXPECTED TO PRODUCE MAINLY MVFR VSBY/S THE NEXT FEW HOURS...WITH
THE POTENTIAL FOR IFR VSBY/S AT AZO. THE BULK OF THE NIGHT WILL
FEATURE MVFR CEILINGS OVERSPREADING THE AREA FROM THE WEST AND
IMPROVING VSBY/S AS THE SNOW SHOWERS MOVE INLAND AND DISSIPATE.
THE MVFR CEILINGS MAY TRY TO HANG ON MUCH OF THE DAY ON SUNDAY
WITH NO RESTRICTION TO VSBY. THE CEILINGS WILL BE LAKE GENERATED.
AN IMPROVEMENT TOWARD VFR SHOULD OCCUR EITHER DURING THE
AFTERNOON OR MORE LIKELY TOWARD EVENING.
&&
.MARINE...
ISSUED AT 351 PM EST SAT DEC 29 2012
NO CHANGES WERE MADE TO THE INHERITED FORECAST. LATEST LOCAL RUN
OF THE GLERL KEEPS WAVES BELOW SMALL CRAFT CRITERIA UNTIL WELL
AFTER MIDNIGHT. THIS IS A FEW HOURS AFTER THE 10 PM OFFICIAL START
OF THE SMALL CRAFT ADVISORY. THERE MAY BE A BRIEF PERIOD OF SUB-
ADVISORY WAVES SUNDAY AFTERNOON. HOWEVER THIS WILL BE SHORT-LIVED
AS WINDS NEAR OR AT GALE FORCE ARE EXPECTED BOTH SUNDAY NIGHT AND
MONDAY.
&&
.HYDROLOGY...
ISSUED AT 321 PM EST SAT DEC 29 2012
NO HYDRO CONCERNS DUE TO VERY LITTLE QPF. RIVER ICE WILL BE LIKELY
TO DEVELOP BY THE END OF THE COMING WORK WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
LMZ844>849.
&&
$$
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...NJJ
AVIATION...DUKE
HYDROLOGY...TJT
MARINE...TJT
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1146 PM EST SAT DEC 29 2012
.AVIATION...
//DISCUSSION...
DRY AIR ADVECTION HAS ALLOWED A SIGNIFICANT CLEARING OVER THE SE MI
TERMINALS. THE LOW LEVEL FLOW WILL HOWEVER BACK TO THE
WEST-SOUTHWEST THIS MORNING. THIS WILL BRING THE LAKE STRATO CU NOW
OVER SW LOWER MI BACK INTO THE AREA. UPSTREAM OBS SUGGEST CEILINGS
WILL BE QUITE VARIABLE WITHIN THESE CLOUDS AND EXPECT THEY WILL
FLUCTUATE BETWEEN MVFR AND VFR THROUGH THE MORNING. THE FLOW WILL
BACK TOWARD THE SOUTHWEST SUN AFTERNOON. THIS ALONG WITH ANOTHER
PUSH OF DRY AIR SHOULD CLEAR THE LOW CLOUDS OUT DURING THE
AFTERNOON.
FOR DTW...THERE IS CHANCE FOR SOME ADDITIONAL FLURRIES LATE TONIGHT
AND SUN MORNING AS A MORE DIRECT WESTERLY FLOW DEVELOPS OFF LAKE MI.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THIS MORNING.
&&
.PREV DISCUSSION...ISSUED 922 PM EST SAT DEC 29 2012
UPDATE...
SOME FAIRLY LARGE BREAKS IN THE CLOUDS HAVE DEVELOPED THIS
EVENING...WHICH WILL REQUIRE A SLIGHT DOWNWARD ADJUSTMENT TO THE
OVERNIGHT MIN TEMP FORECAST. THE LOW LEVEL FLOW WILL TURN MORE
WESTERLY OVERNIGHT...WHICH WILL BRING SOME LAKE STRATUS AND
POSSIBLE FLURRIES BACK INTO SE MI. AN UPDATE WILL BE ISSUED TO
REFLECT THESE CHANGES. THE EXETER ONT RADAR SHOWS THAT THE SNOW
SHOWERS WHICH AFFECTED THE THUMB REGION EARLIER THIS EVENING ARE
NOW WELL OVER THE LAKE THANKS TO THE BACKING FLOW.
PREV DISCUSSION...ISSUED 406 PM EST SAT DEC 29 2012
SHORT TERM...THIS EVENING AND TONIGHT
SURFACE OBSERVATIONS UPSTREAM OVER NORTHERN LAKE HURON SUPPORT THE
MAIN STRUCTURE OF LAKE HURON AGGREGATE TROUGH HAS BROKEN DOWN. HIGH
RESOLUTION MODEL DATA HAS BEEN DEPICTING A SOLUTION THAT SUPPORTED
TRACKING A MESOVORTEX OR WELL ORGANIZED LOW LEVEL CONVERGENCE BANDING
STRUCTURE INTO PORTIONS OF HURON COUNTY AND THE NORTHERN THUMB AS
THE NORTHWESTERLY FLOW BECAME DOMINANT. WITH NO REDUCTION IN SFC
VISIBILITIES EARLIER THIS AFTERNOON FOR THE UPSTREAM SHORELINE AREAS
OF NORTHERN LOWER THIS IDEA FOR A MESOLOW CAN NOW BE ABANDONED. THIS
IS IMPORTANT BECAUSE THE IDEA OF LONGER DURATION DUE TO PROPAGATION
EFFECTS CAN BE APTLY BE DISCOUNTED AS WELL.
THE LAKE EFFECT EVENT NOW ANTICIPATED WILL BE A BRIEF
ONE...RELEGATED TO DEVELOPED ACTIVITY ADVECTING THROUGH ON THE LEAD
BACKED NORTHEASTERLY PUSH...VERY MUCH OF A SQUALL NATURE. SATELLITE
IMAGERY HAS SHOWN LOW CLOUD STRATOCUMULUS AGGRESSIVELY PUSHING INTO
EASTERN HURON COUNTY/MARKED WITH A GRAVITY STRUCTURE DURING THE PAST
HOUR. KDTX/KAPX BEAMS ARE BOTH OVERSHOOTING THE ACTIVITY WITH THE
AREAS OF INTEREST AT ROUGHLY 90 NM OR APPX 10 KFT AGL ON THE .5
DEGREE. ENVIRONMENT CANADA EXETER RADAR IS IN A BETTER LOCATION AND
IS SHOWING 25-30 DBZ EXTENDING INLAND/EAST OF BAD AXE. PLACED SOME
CALLS TO FIELD REPORTS AND DID MANAGE TO GET A CREDIBLE REPORT OF .5
INCH PER ONE HALF HOUR IN PORT HOPE. HOWEVER...THE SNOW HAD ALREADY
BEEN ON THE WANE SUGGESTING A TENUOUS SETUP. VARIOUS HI RESOLUTION
FLAVORS OF NWP - 3.5KM ARW WRF - 4 KM NMM SPC WRF - 3KM HRRR AND 13
KM RAP NOW AGREE IN SWEEPING THIS LAKE EFFECT THROUGH DURING 19-22Z.
DURATION OF SNOWFALL SHOULD ONLY LAST 1-1.5 HOUR AT MOST BEFORE
PUSHING BACK INTO LAKE HURON. THEREFORE...THE FORECAST WILL CALL FOR
A CONDITIONAL...UP TO 2 INCHES FOR LOCATIONS OF HURON/SANILAC
COUNTIES EAST OF A LINE FROM BAD AXE TO SANDUSKY.
OTHERWISE...LARGE SCALE MIDLEVEL TROUGH IS NOW ADVANCING INTO THE
WESTERN PORTIONS OF LOWER MICHIGAN. THE OLD 850-700MB DEFORMATION
FORCING THAT IS A CARRYOVER FROM LAST NIGHT HAS BEEN EFFICIENT IN
GENERATING AFTERNOON LIGHT SNOW/FLURRIES HERE ACROSS MUCH OF THE
REGION. HIGHEST REFLECTIVITIES HAVE BEEN IN EXCESS OF 20 DBZ BUT IS
LACKING IN ANY BITE/MORE OF A FUNCTION OF A FEW LARGE FLAKES. NOT
EXPECTING MUCH ACCUMULATION WITH THIS BEFORE DISSIPATING.
LOWS TONIGHT ARE VERY TRICKY AND DEPENDENT ON CLOUD COVER. DID STEER
THE FORECASTED LOWS A LITTLE TOWARDS RECENT GUIDANCE...AROUND 20
DEGREES.
LONG TERM...SUNDAY THROUGH SATURDAY
QUIET WEATHER EXPECTED SUNDAY/SUNDAY NIGHT AS HIGH PRESSURE BUILDS
ACROSS THE EASTERN CONUS W/ THE NORTHERN EXTENT OF SURFACE RIDGING
PROVIDING RELATIVELY LIGHT WINDS AND PARTLY CLOUDY SKIES FOR THE
SOUTHERN GREAT LAKES. AS THE RIDGE AXIS PROGRESSES EAST OF THE AREA
ON MONDAY...CLOUDS/WINDS WILL INCREASE WITH THE APPROACH OF THE NEXT
DISTURBANCE. THIS SYSTEM WILL CROSS NORTH OF THE AREA...BUT PUSH A
COLD FRONT THROUGH THE REGION BY MONDAY NIGHT.
THE STORM SYSTEM THAT HAS BASICALLY THE ONLY POTENTIAL TO BRING
NOTEWORTHY SNOW TO THE AREA IS CURRENTLY SPINNING OVER CALIFORNIA.
OF THE 12Z MODEL SUITE...THE NAM12 IS THE ONLY MODEL TRYING TO
MAINTAIN SOME INTEGRITY TO THIS WAVE AS IT EJECTS NORTHEAST OUT OF
THE FOUR CORNERS ALONG THE MEAN CENTRAL CONUS UPPER TROUGH INTO A
LARGELY CONFLUENT UPPER FLOW OVER THE NORTHEAST QUADRANT OF THE
NATION.
IN ADDITION TO SHOWING THE STRONGEST SOLUTION FOR THIS SHORTWAVE
ITSELF...THE OTHER MAIN DIFFERENCE IS THE HANDLING OF SHORTWAVE
ENERGY DIGGING SOUTH/SOUTHEAST INTO POLAR VORTEX NEAR HUDSON BAY AS
THE NAM..THROUGH THIS PROCESS...MAINTAINS A MORE NORTHERN POSITION
TO THIS FEATURE AND ALLOWS ITS "STRONGER" WAVE TO EJECT FURTHER
NORTH INTO THE OHIO VALLEY/SOUTHERN GREAT LAKES AND BRING SEVERAL
INCHES OF SNOW TO PARTS OF LOWER MICHIGAN.
WHILE THE ARCTIC JET ENERGY THAT WILL EVENTUALLY DICTATE THE
EVOLUTION OF THE HUDSON BAY LOW AND THE STEERING OF THE SOUTHERN
STREAM WAVE HAS YET TO BE SAMPLED VERY WELL...IT IS HARD TO IGNORE
SUCH A STRONG MODEL CONSENSUS AGAINST THE NAM...WHICH CALLS FOR
STRONGER AMPLIFICATION OF THE NORTHERN STREAM OVER EASTERN CANADA.
THIS SCENARIO WILL SHUNT THE SOUTHERN SYSTEM ON A TRACK WELL SOUTH
OF THE AREA AND KEEP ANY NOTABLE PRECIPITATION CONFINED TO THE
TENNESSEE VALLEY AND POINTS SOUTH WITH IT WITH JUST SCATTERED SNOW
SHOWERS OVER LOWER MICHIGAN WITHIN THE CYCLONIC NORTHWEST FLOW AS
COLDER AIR SURGES THROUGH THE GREAT LAKES WITH THE EVOLUTION OF THIS
NORTHERN SYSTEM.
WILL MAINTAIN A FORECAST BASED ON THIS IDEA...WITH LITTLE/NO CHANCE
OF SIGNIFICANT SNOW AND ALSO A DECENT COOL DOWN AS THIS STRONG
EASTERN CANADA UPPER LOW/TROUGH ALLOWS FOR A DECENT PENETRATION OF
POLAR/MODIFIED ARCTIC AIR INTO THE REGION. SO...AFTER EDGING BACK TO
HIGH TEMPERATURES IN THE 30S ON MONDAY...20S WILL BE THE RULE MUCH
OF THE UPCOMING WEEK WITH LOWS IN THE SINGLE DIGITS/TEENS MUCH OF
THE TIME.
MARINE...
A MODEST INCREASE TO THE SURFACE PRESSURE GRADIENT COMBINED WITH
WINDS ROTATING TO A MORE ONSHORE DIRECTION WILL MAINTAIN A MODERATE
BREEZE ACROSS CENTRAL AND SOUTHERN LAKE HURON TODAY. WAVE HEIGHTS
ARE ALREADY RAMPING UP INTO THE 4 TO 7 FOOT RANGE THIS AFTERNOON.
SMALL CRAFT ADVISORIES REMAIN IN EFFECT FROM OUTER SAGINAW BAY TO
PORT HURON THROUGH TONIGHT.
A MODERATE SOUTHWEST FLOW WILL DEVELOP SUNDAY NIGHT INTO MONDAY AS
THE SURFACE PRESSURE GRADIENT TIGHTENS OVER AREA WATERS AS LOW
PRESSURE CROSSES NORTH OF THE REGION. GUSTY NORTHWEST WINDS WILL
DEVELOP BY MIDWEEK NEXT WEEK AS COLDER AIR SPREADS INTO THE GREAT
LAKES REGION IN THE WAKE OF THIS SYSTEM.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
SANILAC...UNTIL 7 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT SANILAC TO PORT
HURON...UNTIL 10 AM SUNDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...CB
LONG TERM....DG
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
836 PM CST MON DEC 31 2012
.UPDATE...
TEMPERATURES AT 8 PM HAVE ALREADY FALLEN TO BETWEEN 5 AND 10 BELOW
ZERO ACROSS WRN MN...WITH SINGLE DIGITS ABOVE ZERO FURTHER EAST
ACROSS THE TWIN CITIES METRO AND WRN WI. THE RIDGE IS CENTERED
OVER WRN MN ATTM AND IS EXPECTED TO CONTINUE BUILDING SEWD TO SCTRL
MN BY DAWN.
A BANK OF STRATUS OVER SD HAS INCHED ITS WAY EWD TO THE MN STATE
LINE. TEMPERATURES WARMED SEVERAL DEGREES OVER ERN SD AS THIS
STRATUS MOVED OVERHEAD. THUS...COULD SEE TEMPS MODERATE
OVERNIGHT ACROSS FAR WRN MN AS THIS STRATUS MOVES IN. JUST A BIT
FURTHER EAST...IDEAL RADIATIONAL CONDITIONS WILL PERSIST DIRECTLY
UNDER THE RIDGE AND TEMPERATURES ARE EXPECTED TO PLUMMET TO 15 TO
20 BELOW IN MANY PLACES. WINDS MAY REMAIN JUST ELEVATED ENOUGH
OVER WRN WI TO PREVENT FROM REACHING 10 BELOW. THE URBAN HEAT
ISLAND OF THE METRO WILL ALSO KEEP TEMPERATURES IN THE SINGLE
DIGITS BELOW THERE.
WIND HAS WEAKENED QUITE A BIT IN THE PAST COUPLE HOURS AND THERE
ARE DOUBTS THAT WIDESPREAD WIND CHILLS WILL REACH 25 BELOW.
HOWEVER...BY DAWN A RETURN FLOW WILL BEGIN WITH WINDS REACHING 5 KTS
AGAIN. WITH SUCH COLD CONDITIONS IN PLACE...IT WON/T TAKE MUCH
WIND TO OCCASIONALLY REACH WIND CHILLS OF 25 BELOW SO WILL
MAINTAIN THE WIND CHILL ADVISORY.
BORGHOFF
&&
.AVIATION.../00Z TAF ISSUANCE/
DRY/COLD CANADIAN HIGH PRESSURE MOVING SOUTH ACROSS...BUT STRATUS
ON THE BACK SIDE OF THE RIDGE ACROSS THE DKTS IN A LOW LEVEL WAA
REGIME IS WHAT LEADS TO UNCERTAINTIES IN THESE TAFS. GENERALLY
FOLLOWED A RAP/NAM TIMING FOR THESE CLOUDS...WHICH RESULTED IN A
SLIGHT SPEEDING UP OF THEIR ONSET. IN ADDITION...BASED ON OBS TO
THE WEST...BROUGHT THEM DOWN TO MVFR LEVELS AT STC/AXN/RWF. KEPT
MSP/RNH VFR FOR NOW GIVEN THE LATER ARRIVAL OF CLOUDS WHICH SHOULD
LEAD TO HIGH CIGS FARTHER EAST...BUT MVFR CONDS BY THE LATE
AFTERNOON CAN NOT BE RULED OUT AT THESE SITES EITHER. WINDS WILL
BE UNDER 10 KTS THIS PERIOD...WITH NW WINDS BECOMING LGT AND VRB
OVERNIGHT BEFORE TURNING OUT OF THE SW FOR NEW YEARS DAY.
KMSP...BIGGEST CONCERN THIS TAF PERIOD WILL BE EVOLUTION OF
STRATUS CURRENTLY ACROSS THE DKTS AS SFC RIDGE WORKS EAST. RAP IS
PRETTY AGGRESSIVE WITH DRIVING MVFR CIGS ACROSS MN TUESDAY MORNING
/BASED ON 925-850 MB RH/...WITH THE 22Z RAP HAVING MVFR CONDS AT
MSP AS EARLY AS 16Z. THIS IS PROBABLY A BIT AGGRESSIVE...BUT DID
MOVE UP ONSET OF CIGS AT MSP AS A RESULT. WOULD NOT BE SURPRISED
IF CIGS TOMORROW CAME IN BETWEEN 020 AND 030...BUT WITH
UNCERTAINTIES ABOUT JUST HOW WIDESPREAD STRATUS WILL BE BY THE
TIME IT GETS TO MSP...LEFT THEM VFR FOR NOW.
/OUTLOOK FOR KMSP/
WED...MVFR CONDITIONS/-SN POSSIBLE. WSW WINDS 4 TO 8 KTS.
THU...MVFR CEILINGS/FLURRIES POSSIBLE. NW WINDS 8 TO 12 KTS.
FRI...VFR. WINDS SW 5 TO 10 KTS.
&&
.PREV DISCUSSION.../ISSUED 257 PM CST MON DEC 31 2012/
ANOTHER COLD NIGHT TONIGHT AS HIGH PRESSURE SETTLES ACROSS THE
REGION. A WEAK CLIPPER SYSTEM WILL BRING SOME LIGHT SNOW ON
WEDNESDAY...BUT ACCUMULATIONS WILL BE LIGHT. THE REST OF THE
FORECAST WILL BE DRY...WITH A WARM UP EXPECTED THIS WEEKEND WITH
HIGH TEMPERATURES APPROACHING THE THAWING MARK FOR SUNDAY AND
MONDAY.
TODAY THROUGH WEDNESDAY...THE TWO MAIN CHALLENGES WERE LOW
TEMPERATURES TONIGHT...AND HOW TO BEST CONVEY THE LIGHT PRECIP ON
WEDNESDAY. FIRST OF ALL...TONIGHTS LARGE SCALE SET UP IS IDEAL FOR
NOCTURNAL COOLING AS THE SURFACE HIGH SLIDES SOUTHEAST ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY REGION. LIGHT WINDS...CLEAR
SKIES...AND AMPLE SNOW COVER WILL ALLOW TEMPERATURES TO COOL OFF
RATHER QUICKLY AFTER SUNSET. HAVE EXPANDED THE WIND CHILL ADVISORY
ACROSS THE NORTH WHERE COULD SEE VALUES AROUND -25F OVERNIGHT. THE
ONE CAVEAT...ASIDE FROM THE LIGHT WINDS...IS A SUBTLE SHORTWAVE
ACROSS THE WESTERN DAKOTAS AND THE DOWNSTREAM CLOUDS ACROSS THE
CENTRAL DAKOTAS...WHICH WILL HOLD UP TEMPERATURES IF THEY MOVE
OVERHEAD TONIGHT. THESE WILL MOST LIKELY AFFECT SOUTHWEST
MINNESOTA...BUT DID NOT CANCEL ANY OF THE WIND CHILL ADVISORY
SINCE THERE IS STILL POTENTIAL FOR SUBSTANTIAL COOLING
OVERNIGHT...AND IT IS NEW YEARS EVE. AFTER A CHILLY DRY
TUESDAY...A WEAKENING SHORTWAVE WILL SPREAD A BROAD AREA OF UPWARD
FORCING ACROSS THE REGION...AND FORECAST SOUNDINGS SHOW SATURATION
WITH WEAK LIFT...WHICH SHOULD BE ENOUGH TO PRODUCE LIGHT SNOW ON
WEDNESDAY. LIQUID AMOUNTS WILL BE ON THE ORDER OF A COUPLE OF
HUNDREDTHS OR SO...BUT RATIOS SHOULD BE NEAR 20:1. THEREFORE HAVE
SNOWFALL TOTALS OF AROUND A HALF INCH TO A INCH FOR
WEDNESDAY...WITH LIKELY POPS. THE UPSTREAM WAVE BREAKING TO THE
NORTH...AND STRONG ZONAL JET ACROSS THE OHIO RIVER VALLEY WILL
SHEAR OUT THIS SYSTEM...SO IT WILL BECOME LESS ORGANIZED AS IT
TRAVERSES THE REGION. HOWEVER...DECIDED TO GO WITH LIKELY
POPS...SINCE IT WILL SNOW ON WEDNESDAY...BUT HAVE LIGHT QPF
AMOUNTS SINCE MEASURABLE PRECIP IS STILL SOMEWHAT QUESTIONABLE.
THURSDAY THROUGH MONDAY...TOWARDS THE END OF THE WEEK THE UPPER
LEVEL FLOW WILL TRANSITION FROM NORTHWESTERLY TO MORE WESTERLY
ACROSS THE MONTANA/CANADA BORDER. THIS WILL LEAD TO SIGNIFICANT LEE
SIDE WARMING OVER THE HIGH PLAINS...WHICH WILL BE ADVECTED ACROSS
THE REGION FOR THE WEEKEND. H900 TEMPERATURES OF +3 TO +5C WILL
SET THE STAGE FOR A WARM UP ON SUNDAY AND MONDAY. FOR NOW IT
APPEARS THE LOW LEVEL INVERSION WILL MITIGATE ANY SIGNIFICANT
SNOW MELT...BUT SHOULD SEE TEMPERATURES APPROACH THE 32F MARK. A
FEW WEAK WAVES TRACK ACROSS THE NORTH...BUT FOR NOW HAVE LEFT THE
EXTENDED FORECAST DRY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 9 AM CST TUESDAY FOR BENTON-BLUE EARTH-
BROWN-CHIPPEWA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-ISANTI-
KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-
MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-REDWOOD-RENVILLE-
RICE-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-
WASECA-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
JRB/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
604 PM CST MON DEC 31 2012
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREVIOUS DISCUSSION...
/ISSUED 257 PM CST MON DEC 31 2012/
ANOTHER COLD NIGHT TONIGHT AS HIGH PRESSURE SETTLES ACROSS THE
REGION. A WEAK CLIPPER SYSTEM WILL BRING SOME LIGHT SNOW ON
WEDNESDAY...BUT ACCUMULATIONS WILL BE LIGHT. THE REST OF THE
FORECAST WILL BE DRY...WITH A WARM UP EXPECTED THIS WEEKEND WITH
HIGH TEMPERATURES APPROACHING THE THAWING MARK FOR SUNDAY AND
MONDAY.
TODAY THROUGH WEDNESDAY...THE TWO MAIN CHALLENGES WERE LOW
TEMPERATURES TONIGHT...AND HOW TO BEST CONVEY THE LIGHT PRECIP ON
WEDNESDAY. FIRST OF ALL...TONIGHTS LARGE SCALE SET UP IS IDEAL FOR
NOCTURNAL COOLING AS THE SURFACE HIGH SLIDES SOUTHEAST ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY REGION. LIGHT WINDS...CLEAR
SKIES...AND AMPLE SNOW COVER WILL ALLOW TEMPERATURES TO COOL OFF
RATHER QUICKLY AFTER SUNSET. HAVE EXPANDED THE WIND CHILL ADVISORY
ACROSS THE NORTH WHERE COULD SEE VALUES AROUND -25F OVERNIGHT. THE
ONE CAVEAT...ASIDE FROM THE LIGHT WINDS...IS A SUBTLE SHORTWAVE
ACROSS THE WESTERN DAKOTAS AND THE DOWNSTREAM CLOUDS ACROSS THE
CENTRAL DAKOTAS...WHICH WILL HOLD UP TEMPERATURES IF THEY MOVE
OVERHEAD TONIGHT. THESE WILL MOST LIKELY AFFECT SOUTHWEST
MINNESOTA...BUT DID NOT CANCEL ANY OF THE WIND CHILL ADVISORY
SINCE THERE IS STILL POTENTIAL FOR SUBSTANTIAL COOLING
OVERNIGHT...AND IT IS NEW YEARS EVE. AFTER A CHILLY DRY
TUESDAY...A WEAKENING SHORTWAVE WILL SPREAD A BROAD AREA OF UPWARD
FORCING ACROSS THE REGION...AND FORECAST SOUNDINGS SHOW SATURATION
WITH WEAK LIFT...WHICH SHOULD BE ENOUGH TO PRODUCE LIGHT SNOW ON
WEDNESDAY. LIQUID AMOUNTS WILL BE ON THE ORDER OF A COUPLE OF
HUNDREDTHS OR SO...BUT RATIOS SHOULD BE NEAR 20:1. THEREFORE HAVE
SNOWFALL TOTALS OF AROUND A HALF INCH TO A INCH FOR
WEDNESDAY...WITH LIKELY POPS. THE UPSTREAM WAVE BREAKING TO THE
NORTH...AND STRONG ZONAL JET ACROSS THE OHIO RIVER VALLEY WILL
SHEAR OUT THIS SYSTEM...SO IT WILL BECOME LESS ORGANIZED AS IT
TRAVERSES THE REGION. HOWEVER...DECIDED TO GO WITH LIKELY
POPS...SINCE IT WILL SNOW ON WEDNESDAY...BUT HAVE LIGHT QPF
AMOUNTS SINCE MEASURABLE PRECIP IS STILL SOMEWHAT QUESTIONABLE.
THURSDAY THROUGH MONDAY...TOWARDS THE END OF THE WEEK THE UPPER
LEVEL FLOW WILL TRANSITION FROM NORTHWESTERLY TO MORE WESTERLY
ACROSS THE MONTANA/CANADA BORDER. THIS WILL LEAD TO SIGNIFICANT LEE
SIDE WARMING OVER THE HIGH PLAINS...WHICH WILL BE ADVECTED ACROSS
THE REGION FOR THE WEEKEND. H900 TEMPERATURES OF +3 TO +5C WILL
SET THE STAGE FOR A WARM UP ON SUNDAY AND MONDAY. FOR NOW IT
APPEARS THE LOW LEVEL INVERSION WILL MITIGATE ANY SIGNIFICANT
SNOW MELT...BUT SHOULD SEE TEMPERATURES APPROACH THE 32F MARK. A
FEW WEAK WAVES TRACK ACROSS THE NORTH...BUT FOR NOW HAVE LEFT THE
EXTENDED FORECAST DRY.
&&
.AVIATION.../00Z TAF ISSUANCE/
DRY/COLD CANADIAN HIGH PRESSURE MOVING SOUTH ACROSS...BUT STRATUS
ON THE BACK SIDE OF THE RIDGE ACROSS THE DKTS IN A LOW LEVEL WAA
REGIME IS WHAT LEADS TO UNCERTAINTIES IN THESE TAFS. GENERALLY
FOLLOWED A RAP/NAM TIMING FOR THESE CLOUDS...WHICH RESULTED IN A
SLIGHT SPEEDING UP OF THEIR ONSET. IN ADDITION...BASED ON OBS TO
THE WEST...BROUGHT THEM DOWN TO MVFR LEVELS AT STC/AXN/RWF. KEPT
MSP/RNH VFR FOR NOW GIVEN THE LATER ARRIVAL OF CLOUDS WHICH SHOULD
LEAD TO HIGH CIGS FARTHER EAST...BUT MVFR CONDS BY THE LATE
AFTERNOON CAN NOT BE RULED OUT AT THESE SITES EITHER. WINDS WILL
BE UNDER 10 KTS THIS PERIOD...WITH NW WINDS BECOMING LGT AND VRB
OVERNIGHT BEFORE TURNING OUT OF THE SW FOR NEW YEARS DAY.
KMSP...BIGGEST CONCERN THIS TAF PERIOD WILL BE EVOLUTION OF
STRATUS CURRENTLY ACROSS THE DKTS AS SFC RIDGE WORKS EAST. RAP IS
PRETTY AGGRESSIVE WITH DRIVING MVFR CIGS ACROSS MN TUESDAY MORNING
/BASED ON 925-850 MB RH/...WITH THE 22Z RAP HAVING MVFR CONDS AT
MSP AS EARLY AS 16Z. THIS IS PROBABLY A BIT AGGRESSIVE...BUT DID
MOVE UP ONSET OF CIGS AT MSP AS A RESULT. WOULD NOT BE SURPRISED
IF CIGS TOMORROW CAME IN BETWEEN 020 AND 030...BUT WITH
UNCERTAINTIES ABOUT JUST HOW WIDESPREAD STRATUS WILL BE BY THE
TIME IT GETS TO MSP...LEFT THEM VFR FOR NOW.
/OUTLOOK FOR KMSP/
WED...MVFR CONDITIONS/-SN POSSIBLE. WSW WINDS 4 TO 8 KTS.
THU...MVFR CEILINGS/FLURRIES POSSIBLE. NW WINDS 8 TO 12 KTS.
FRI...VFR. WINDS SW 5 TO 10 KTS.
&&
.PREV DISCUSSION...
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST TUESDAY
FOR BENTON-BLUE EARTH-BROWN-CHIPPEWA-DOUGLAS-FARIBAULT-
FREEBORN-GOODHUE-ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE
SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-
POPE-REDWOOD-RENVILLE-RICE-SHERBURNE-SIBLEY-STEARNS-STEELE-
STEVENS-SWIFT-TODD-WASECA-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
JRB/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
323 AM CST SUN DEC 30 2012
.DISCUSSION...
FOREMOST WEATHER CONCERNS OVER THE NEXT SEVEN DAYS ARE
PRECIPITATION CHANCES TONIGHT AND WEDNESDAY...AND LOW TEMPERATURES
AND WIND CHILL VALUES FOR NEW YEARS EVE/DAY.
EARLY MORNING SURFACE ANALYSIS AND SATELLITE IMAGERY SHOW A
SURFACE RIDGE IN PLACE OVER THE FORECAST AREA. STRATUS CLOUDS ON
THE NORTHERN PERIPHERY OF THE RIDGE HAVE AFFECTED THE FAR WEST
CENTRAL WI COUNTIES OVERNIGHT...ALTHOUGH THE MAJORITY OF THE AREA
HAS EXPERIENCED MOSTLY CLEAR SKIES AND LIGHT WINDS. LIGHT FOG HAS
FORMED IN A FEW LOCATIONS...ALTHOUGH DRY AIR /SUB-ZERO DEWPOINTS/
OVER MUCH OF CWA HAS LIMITED DEVELOPMENT.
THE AFOREMENTIONED RIDGE SHIFTS EAST OF THE AREA TODAY...AND IS
REPLACED BY INCREASING SOUTHERLY LOW LEVEL FLOW AHEAD OF A MID
LEVEL TROUGH PASSING ACROSS ONTARIO. THE SURFACE FRONT ASSOCIATED
WITH SAID TROUGH PASSES ACROSS THE AREA TONIGHT INTO MONDAY. WHILE
ANY EVIDENCE OF MOISTURE/LIFT WITH THIS FEATURE IS SCANT...THERE
CONTINUES TO BE A WEAK LIFT SIGNATURE ON THE 275K ISENTROPIC
SURFACE PROGGED FROM SOUTH CENTRAL MN NORTHEAST ACROSS WEST
CENTRAL WI AS VERY MODEST MOISTURE ADVECTION ENSUES. HAVE RETAINED
A MENTION OF FREEZING DRIZZLE ROUGHLY FROM ALBERT LEA TO RED WING
TO LADYSMITH WI FOR LATE TONIGHT INTO MONDAY MORNING...WITH MODEL
SOUNDINGS CONTINUING TO DEPICT AN UNSATURATED DENDRITIC ZONE.
NEARLY STEADY TO FALLING TEMPS APPEAR TO BE THE MOST LIKELY TREND
ON MONDAY GIVEN THE TIMING OF THE FRONTAL PASSAGE.
ARCTIC AIR THEN INVADES THE UPPER MIDWEST IN THE WAKE OF THE
FRONT...WITH PREVIOUSLY FORECAST NEW YEAR/S MORNING/S LOWS OF -10
TO -20 APPEARING ON TARGET. DEPENDING ON HOW MUCH WINDS DROP OFF
WITH THE ARRIVAL OF THE RIDGE...MAY EVENTUALLY NEED A WIND CHILL
ADVISORY FOR MONDAY NIGHT INTO TUESDAY MORNING.
THE NEXT CHANCE FOR SNOWFALL ARRIVES ON WEDNESDAY INTO
THURSDAY...AS A TROUGH DROPS OUT OF SASKATCHEWAN/MANITOBA AND
CLIPS THE AREA. MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS
FEATURE...SO HAVE INTRODUCED LOW CHANCE POPS. WILL LIKELY NEED TO
INCREASE POPS MORE AS CONFIDENCE INCREASES...BUT SNOWFALL AMOUNTS
WOULD LIKELY BE RELATIVELY LOW /INCH OR LESS/ IN THIS TYPE OF
PATTERN.
TEMPERATURES GRADUALLY MODERATE INTO THE WEEKEND WITH HIGHS IN THE
LOW/MID 20S.
&&
.AVIATION.../06Z TAF ISSUANCE/
LARGE AREA OF MVFR CEILINGS MOVING SLOWLY EAST THROUGH WESTERN
WISCONSIN. LATEST RAP AND SATELLITE TRENDS SUGGEST IT SHOULD EXIT
KEAU AROUND 08Z. BELIEVE SKY SHOULD BE MOSTLY CLEAR WITH VSBY
ABOVE 5SM THROUGH THE NIGHT...WITH ANY FOG BEING RATHER LOCALIZED.
SURFACE RIDGE OVER MN AT THIS TIME...BUT IT SHOULD BE OVER WESTERN
WISC BY 12Z. THIS WILL ALLOW SOUTH WINDS TO PICK UP ACROSS WESTERN
AND CENTRAL MN. LARGE SWATH OF MID/HIGH CLOUDS ALSO MOVING IN FROM
THE DAKOTAS. SO BETWEEN THE STEADY WIND AND THE CLOUD...THINK FOG
WILL NOT BE WIDESPREAD. WESTERN WISC IS THE AREA TO WATCH FOR
MORE FOG/STRATUS WITH RIDGE AXIS. HAVE ADDED SOME 4-5SM VSBY IN
FOG AT KEAU AND KRNH. INCOMING FRONT LOOKS TO REACH KAXN LATE
SUNDAY AFTERNOON WITH MVFR STRATUS...THEN PROGRESS SOUTHEAST WITH
MVFR STRATUS SPREADING OVER THE REGION.
KMSP...SMALL POTENTIAL FOR MVFR CEILING/VSBY TO REDEVELOP AFTER
06Z. IF THAT HAPPENS...CEILINGS WOULD PROBABLY BE AROUND
1200 FT AGL ALONG WITH VSBY AROUND 5SM. BUT THIS SEEMS UNLIKELY AS
HIGH CLOUDS APPROACH. SUNDAY WILL FEATURE LIGHT SOUTHERLY WINDS
WITH NEXT ARCTIC FRONT ARRIVING AROUND 03Z MONDAY WITH SOME MVFR
CEILINGS AROUND 2000 FT AGL.
/OUTLOOK FOR KMSP/
MON...VFR. WINDS NW 10-15 KTS.
TUE...VFR. WINDS SW 5-10 KTS.
WED...VFR. SLIGHT CHANCE OF MVFR AND LIGHT SNOW. WINDS NW 5-10
KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/TDK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1035 PM CST SAT DEC 29 2012
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
/ISSUED 406 PM CST SAT DEC 29 2012/
OVERVIEW...MOSTLY CLEAR AND COLD TONIGHT WITH CONTINUING COLD
TEMPERATURES THROUGH THE NEW YEAR. THE NEXT CHANCE FOR LIGHT
PRECIP ARRIVES SUNDAY NIGHT INTO MONDAY MORNING WITH A SMALL
CHANCE FOR LIGHT FREEZING DRIZZLE IN SOUTHEAST MN AND PORTIONS OF
WESTERN WI. THE NEXT CHANCE FOR LIGHT SNOW WILL BE WEDNESDAY INTO
THURSDAY. ALTHOUGH...THERE IS STILL A LOT OF UNCERTAINTY WITH THIS
SYSTEM AND IT DOESN`T LOOK PARTICULARLY STRONG AT THIS TIME. NEW
YEARS EVE LOOKS LIKE THE COLDEST NIGHT OF THE WINTER SEASON SO FAR
IN MANY LOCATIONS.
FLOW BECOMES ANTICYCLONIC TONIGHT AS TROUGH SUPPLYING ALL THE SNOW
TO THE EAST COAST CONTINUES ITS EASTWARD TRACK. TROUGH DROPPING
SOUTH OUT OF THE INTERIOR OF CANADA MOVES ACROSS LAKE WINNIPEG BY
THIS TIME TOMORROW. LIGHT SNOW LOOKS POSSIBLE IN FAR NORTHERN
MN TOMORROW...BUT EVEN WITH A COUPLE MORE SUBTLE SHORTWAVES
TRAILING THIS FEATURE AND A SLIGHT SURFACE REFLECTION/COLD
FRONT...MOST OF MN/WI WILL REMAIN DRY. THERE ISN`T MUCH
FORCING/FGEN...BUT THERE IS LOW LEVEL WARM AIR ADVECTION AND A
MODEST AMOUNT OF MOISTURE TRANSPORT TOMORROW NIGHT. WE WARM TEMPS
TOMORROW TO REFLECT OUR THINKING OF MOSTLY CLEAR SKIES AND
SOUTHWEST FLOW. THE GFS/NAM SUGGEST SATURATION FROM ABOUT 900-925
MB TO THE SFC. CHECKING OUT THE ISENTROPIC SURFACES...A DECENT
AMOUNT OF UPGLIDE ON THE 270-280 ISENTROPIC SURFACES...WHICH WOULD
BE IN THE SATURATION. SOUNDINGS STAY MOSTLY ABOVE -10 C...KEEPING
ICE OUT OF THE CLOUD...AND MAKING FREEZING DRIZZLE THE MORE
PROBABLE PREIP TYPE. WE ADDED PATCHY FREEZING DRIZZLE TO THE
FORECAST...BUT LEFT POPS BELOW 15% AT THIS TIME. BETTER SATURATION
LOOKS TO OCCUR IN SOUTHEAST MN AND PORTIONS OF SOUTHWEST/WEST
CENTRAL WI.
AFTER SUNDAY NIGHT...MUCH OF THE COUNTRY WILL SEE A STEADY SUPPLY
OF DRY CONTINENTAL AIR...WITH TRUE ARCTIC AIR INTRUDING INTO THE
NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY EARLY THIS
WEEK. THE MODEL GUIDANCE IS STILL QUITE VARIED IN FORECAST LOWS
NEW YEARS EVE. THE GEM/EC/NAM SUGGEST QUITE A FEW LOCATIONS WILL BE
-10 TO -20 BELOW BY TUESDAY MORNING. THE EARLY MORNING FORECAST
/PREVIOUSLY ISSUED/ DID A GOOD JOB DRIVING TEMPS DOWN BEHIND THE
ARCTIC BOUNDARY. SO...REALLY DIDN`T CHANGE TEMPS A WHOLE LOT FROM
WHAT WAS PREVIOUSLY FORECASTED.
ALL BUT THE GEM NOW FORECAST MOST OF THE LIGHT SNOW ACROSS
CENTRAL/NORTHERN MN AND NORTHERN WI WEDNESDAY NIGHT AND
THURSDAY...OR NOT AT ALL /GFS/. THE 29.12Z EC HAS TRENDED TOWARD A
DEEPER SURFACE LOW BUT ALSO SHIFTED ABOUT A HALF STATE TO THE NORTH.
THIS IS A CLIPPER SYSTEM WITH LIGHT QPF AND HIGH SNOW RATIOS...BUT
THERE IS STILL TOO MUCH UNCERTAINTY TO INCLUDE MUCH HIGHER THAN
SLIGHT CHANCE POPS AT THIS POINT.
&&
.AVIATION.../06Z TAF ISSUANCE/
LARGE AREA OF MVFR CEILINGS MOVING SLOWLY EAST THROUGH WESTERN
WISCONSIN. LATEST RAP AND SATELLITE TRENDS SUGGEST IT SHOULD EXIT
KEAU AROUND 08Z. BELIEVE SKY SHOULD BE MOSTLY CLEAR WITH VSBY
ABOVE 5SM THROUGH THE NIGHT...WITH ANY FOG BEING RATHER LOCALIZED.
SURFACE RIDGE OVER MN AT THIS TIME...BUT IT SHOULD BE OVER WESTERN
WISC BY 12Z. THIS WILL ALLOW SOUTH WINDS TO PICK UP ACROSS WESTERN
AND CENTRAL MN. LARGE SWATH OF MID/HIGH CLOUDS ALSO MOVING IN FROM
THE DAKOTAS. SO BETWEEN THE STEADY WIND AND THE CLOUD...THINK FOG
WILL NOT BE WIDESPREAD. WESTERN WISC IS THE AREA TO WATCH FOR
MORE FOG/STRATUS WITH RIDGE AXIS. HAVE ADDED SOME 4-5SM VSBY IN
FOG AT KEAU AND KRNH. INCOMING FRONT LOOKS TO REACH KAXN LATE
SUNDAY AFTERNOON WITH MVFR STRATUS...THEN PROGRESS SOUTHEAST WITH
MVFR STRATUS SPREADING OVER THE REGION.
KMSP...SMALL POTENTIAL FOR MVFR CEILING/VSBY TO REDEVELOP AFTER
06Z. IF THAT HAPPENS...CEILINGS WOULD PROBABLY BE AROUND
1200 FT AGL ALONG WITH VSBY AROUND 5SM. BUT THIS SEEMS UNLIKELY AS
HIGH CLOUDS APPROACH. SUNDAY WILL FEATURE LIGHT SOUTHERLY WINDS
WITH NEXT ARCTIC FRONT ARRIVING AROUND 03Z MONDAY WITH SOME MVFR
CEILINGS AROUND 2000 FT AGL.
/OUTLOOK FOR KMSP/
MON...VFR. WINDS NW 10-15 KTS.
TUE...VFR. WINDS SW 5-10 KTS.
WED...VFR. SLIGHT CHANCE OF MVFR AND LIGHT SNOW. WINDS NW 5-10
KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/TDK
AREA FORECAST DISCUSSION
NWS BILLINGS MT
546 PM MST MON DEC 31 2012
.SHORT TERM...VALID FOR TUE AND WED...
WE UPDATED THE FORECAST TO INCREASE POPS FOR SNOW SHOWERS UNTIL 06
UTC OVER SOUTH CENTRAL MT IN RESPECT TO THE LATEST RADAR TRENDS. A
QUICK BURST OF MODERATE 500-300 HPA Q-VECTOR CONVERGENCE TIED TO A
SHORT WAVE TROUGH AND A 70 KT 300-HPA JET STREAK WILL BE ENOUGH TO
GENERATE AT LEAST SOME LIGHT SNOW SHOWERS. THE 22 UTC RAP SOLUTION
IS ESPECIALLY ROBUST WITH LIGHT SNOW AROUND BILLINGS...BUT WE FEEL
THAT IT IS OVERDONE WITH ITS QPF WITH OUR RELATIVELY DRY AIR MASS.
THE FORECAST IS THUS WORDED AS SCATTERED SNOW SHOWERS WITH POPS IN
THE 30 PERCENT RANGE OVER SOUTH CENTRAL MT AND SHERIDAN COUNTY WY.
IN ADDITION...WE ADDED FLURRIES TO THE FORECAST THROUGH 06 UTC FOR
SOUTHEAST MT FROM MILES CITY TO BAKER AND EKALAKA. SCHULTZ
PREVIOUS DISCUSSION...ISSUED AT 247 PM MST MON DEC 31 2012...
WEAK SHORTWAVE EMBEDDED IN NORTH FLOW ALOFT IS NOW PRODUCING SOME
ECHOES IN NORTH CENTRAL MT...PERHAPS SOME LIGHT SNOW SHOWERS OR
FLURRIES...WHICH ARE APPROACHING OUR AREA THIS AFTERNOON. IR CLOUD
TOPS OF -20C TO -25C ARE CONSISTENT WITH RAP/NAM MOISTENING OF
DENDRITIC LAYER...AND MODELS HAVE TRENDED UP WITH THE QPF
GENERATED FROM 21-06Z...SO SOME CONFIDENCE IN HIGHER POPS DURING
THIS PERIOD. LOW DEWPTS AND LOW LEVEL DOWNSLOPE WINDS WILL WORK
AGAINST PCPN...SO BELIEVE ONLY LIGHT SNOW SHOWERS OR FLURRIES ARE
WHAT WE WILL EXPERIENCE. HAVE RAISED POPS OVER OUR MTNS AND
SOUTHERN UPSLOPE AREAS DURING THIS TIME PERIOD. MIGHT SEE UP TO AN
INCH OVER THE HIGH TERRAIN. RIDGING WILL ALLOW THE PCPN TO TAPER
OFF BY 6-12Z TONIGHT...WITH A DRY PERIOD IN STORE FROM THEN TO
MIDDAY TUESDAY AS WE AWAIT NEXT CLIPPER IN BRITISH COLUMBIA.
FORCING FROM NEXT CANADIAN SHORTWAVE COMBINED WITH MID LEVEL
TEMPERATURES STILL FAVORABLE FOR DENDRITIC SNOW GROWTH SHOULD
YIELD A NNW TO SSE MOVING AREA OF SNOW SHOWERS TOMORROW
AFTERNOON INTO THE EVENING...WITH GOOD MODEL CONSENSUS WITH THE
TIMING HERE. MOISTURE WILL NOT BE GREAT BUT COULD SEE AROUND AN
INCH OF SHORT-LIVED ACCUMULATION OVER OUR NW UPSLOPE AREAS MAINLY
SOUTH/SOUTHEAST OF BILLINGS. POTENTIAL IMPACTS WOULD INCLUDE
REDUCED VSBY AND SNOWY CONDITIONS ALONG I-94 THROUGH THE HYSHAM
HILLS AND HIGHWAY 212 THROUGH LAME DEER.
ADDITIONAL ENERGY WITHIN CYCLONIC NORTH FLOW ALOFT WILL KEEP THE
-SHSN CHANCES GOING NEAR THE DAKOTAS BORDER THROUGH TUESDAY NIGHT
AND WEDNESDAY. AGAIN...A MOIST DENDRITIC LAYER WILL HELP THE CAUSE
HERE. HAVE EXTENDED LIKELY POPS THROUGH WEDNESDAY AFTERNOON IN
FALLON AND CARTER COUNTIES. 25-35 KT BOUNDARY LAYER WINDS MAY
RESULT IN SOME BLOWING SNOW IN THESE AREAS AS WELL. TEMPS WILL
ALSO BE MUCH COLDER IN OUR EAST PER POOL OF 850MB TEMPS TO -10C TO
-14C. WILL HIGHLIGHT THE TUESDAY/WEDNESDAY PERIOD IN HWO/GRAPHIC.
WESTERN PARTS WILL BE DRIER WITH ENHANCED DOWNSLOPE WINDS
ESPECIALLY AFTER PASSAGE OF TUESDAY CLIPPER. HAVE REDUCED POPS
FROM BILLINGS WEST LATE TOMORROW NIGHT AND WEDNESDAY. RIDGE WILL
BUILD WITH SIGNIFICANTLY RISING HEIGHTS FROM THE WEST WEDNESDAY
NIGHT. SO...A COLD NIGHT IN OUR EAST WITH SFC RIDGING BUT ONSET
OF LEE SIDE TROFFING AND GUSTY WINDS IN OUR WEST LATE WEDNESDAY
NIGHT. THE BUILDING RIDGE ALOFT WILL BRING ABOUT A PATTERN SHIFT
AFTER A COUPLE WEEKS OF COOLER THAN NORMAL WEATHER.
JKL
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MODEL CONFIDENCE IN THE EXTENDED FORECAST HAS IMPROVED TODAY...AS
THE ECMWF HAS TRENDED TOWARD THE GFS/GEFS/GEM/EC ENSEMBLE
SOLUTIONS AS EXPECTED.
RIDGING WILL BUILD INTO THE FORECAST AREA ON THURSDAY...PROMOTING
A RETURN TO DOWNSLOPE FLOW AND WARMING 850 MB TEMPERATURES. MODELS
ARE CONSISTENT WITH WARMING 850 MB TEMPERATURES TO THE +5 TO +10 C
RANGE BY THURSDAY AFTERNOON. PRESSURE FALLS ALONG THE FRONT RANGE AND
LEE SIDE TROUGHING WILL INDUCE A TIGHTENING WEST TO EAST PRESSURE
GRADIENT ACROSS WESTERN ZONES DURING THE DAY THURSDAY. SNOW COVER
WILL BE A COMPETING FACTOR ON THURSDAY...ACTING TO LIMIT THE
EXTENT OF WARMING. ANOTHER COMPETING FACTOR FOR THE BILLINGS AREA
WILL BE THE CLARKS FORK DRAINAGE AS TEMPERATURES IN THE BIG HORN
BASIN CONTINUE TO BE VERY COLD...WITH THURSDAY MORNING
TEMPERATURES THERE EXPECTED TO BE BELOW ZERO. THUS FOR THIS
FORECAST PACKAGE...HAVE WARMED TEMPERATURES ON THURSDAY WEST OF
BILLINGS...ESPECIALLY FOR AREAS FROM LIVINGSTON TO BIG TIMBER AND
NORTH TOWARD HARLOWTON. WARMED BILLINGS SOME OVER THE PREVIOUS
FORECAST...BUT EXPECT THE CLARKS FORK DRAINAGE TO KEEP BILLINGS
FROM WARMING AS MUCH AS AREAS WEST. FOR EASTERN MONTANA...THE LEE
SIDE TROUGH WILL KEEP SOUTHERLY WINDS IN PLACE WITH LIMITED MIXING
POTENTIAL...THUS HIGH TEMPERATURES WILL STRUGGLE TO GET ABOVE
FREEZING THERE.
A WAVE WILL APPROACH THE FORECAST AREA ON FRIDAY...AS IT RIDES
OVER THE TOP OF THE RIDGING ACROSS THE WESTERN CONUS. THIS WAVE
WILL FORCE A WEAK COLD FRONT THROUGH THE AREA FRIDAY AFTERNOON.
HOWEVER...TEMPERATURES ALOFT WILL COOL AS THE WAVE MOVES ACROSS
THE FORECAST AREA...AND PROMOTE BETTER MIXING JUST AHEAD OF AND
BEHIND THE COLD FRONT. THUS THIS WAVE MAY ACTUALLY PROMOTE BETTER
WARMING ACROSS THE FORECAST AREA ON FRIDAY. HAVE INCREASED
TEMPERATURE FORECASTS FOR FRIDAY AS WELL...TO REFLECT THIS
THINKING. THE PRECIPITATION THREAT FROM THIS WAVE LOOKS MINIMAL AT
THIS POINT...WITH MODELS SHOWING A DISTINCT LACK OF MOISTURE AND
STRONG DOWNSLOPE FLOW ACROSS THE FORECAST AREA.
FOR SATURDAY THROUGH EARLY NEXT WEEK...MODELS SHOW BROAD LARGE-SCALE
RIDGING DOMINATING OVER THE FORECAST AREA...WITH THE COLD AIR
SUFFICIENTLY LOCKED UP IN CANADA. TEMPERATURES WILL REMAIN ABOVE
NORMAL THROUGH THE EXTENDED...WITH PERIODS OF WIND RETURNING
ACROSS WESTERN ZONES AND INTO BILLINGS. CONTINUED INCREASING
TEMPERATURES AND WINDS WITH THIS FORECAST PACKAGE. MAINLY THIS
WILL BE A DRY AND QUIET PERIOD OF WEATHER...WITH THE EXCEPTION OF
THE WIND. THE NEXT BEST CHANCE OF ANY SIGNIFICANT WEATHER MAY NOT
BE UNTIL LATER NEXT WEEK AS FORECAST MODELS ARE CONSISTENT WITH
SOME SORT OF A PACIFIC TROUGH IMPACTING THE WESTERN CONUS. CHURCH
&&
.AVIATION...
A DISTURBANCE WILL DROP SOUTHWARD THROUGH THE REGION
TONIGHT GENERATING SNOW SHOWERS ACROSS WESTERN AND CENTRAL
ROUTES. MOST OF THE AREA WILL REMAIN VFR...BUT LOCALIZED MVFR AND
MOUNTAIN OBSCURATIONS WILL BE POSSIBLE IN THE HEAVIER SNOW
SHOWERS.
A COLD FRONT WILL DROP SOUTHWARD THROUGH THE AREA TUESDAY
AFTERNOON...SWITCHING WINDS TO A NW DIRECTION. THE FRONT WILL ALSO
BRING LIGHT SNOW WITH OCCASIONAL MVFR/IFR TO AREAS ALONG AND EAST
OF A LAVINA TO LAUREL TO KSHR LINE. MOUNTAIN OBSCURATIONS ARE
LIKELY TOMORROW...ESPECIALLY IN THE PRYORS AND BIG HORNS. STC
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 016/031 015/030 013/036 022/040 020/042 024/043 025/046
35/J 20/B 00/N 00/N 00/U 00/N 00/N
LVM 016/027 010/027 016/040 024/041 020/041 026/043 027/044
22/J 10/N 00/N 00/N 00/N 00/N 01/N
HDN 007/030 009/028 002/030 013/038 013/037 019/041 019/039
37/J 51/B 00/U 00/U 00/U 00/B 00/B
MLS 007/029 012/023 001/030 013/035 014/037 018/038 020/038
18/J 63/J 00/U 00/U 00/U 00/B 00/B
4BQ 005/030 012/024 002/031 011/037 014/037 017/040 017/038
27/J 73/J 10/U 00/U 00/U 00/B 00/B
BHK 004/026 012/019 902/029 013/033 013/036 017/038 019/038
18/J 66/J 10/U 00/U 00/U 00/B 00/B
SHR 006/031 012/026 002/036 017/039 014/039 018/041 017/041
36/J 51/B 00/U 00/U 00/U 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
941 PM EST MON DEC 31 2012
.SYNOPSIS...
A COLD FRONT WILL PASS THROUGH THE REGION LATE TONIGHT BRINGING
SCATTERED SNOW SHOWERS AND FLURRIES. LITTLE SNOW IS EXPECTED BUT
OVER ONEIDA, ONONDAGA AND MADISON COUNTIES, 1 TO 3 INCHES IS
POSSIBLE. LAKE EFFECT SNOW SHOWERS WILL DROP SOUTH ACROSS CENTRAL
NEW YORK ON WEDNESDAY WHILE WEAKENING. ANOTHER FRONT WILL PUSH
THROUGH THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
BRINGING ANOTHER ROUND OF SCATTERED SNOW SHOWERS AND LAKE EFFECT
SNOWS.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
940 PM UPDATE...
QUICK UPDATE TO ACCOUNT FOR LATEST TRENDS. LATEST RADAR DATA
SHOWING A BAND OF SNOW EXTENDING EAST ACROSS THE SOUTHERN TIER
THIS EVENING WITH SNOW JUST BEGINNING HERE AT THE AIRFIELD. IN ALL
ACTUALITY...FAIRLY DECENT FORCING FOR ONGOING SNOWFALL AS REGION
RESIDES UNDER THE LEFT EXIT REGION OF A 200+ KT UPPER JETSTREAK TO
OUR SOUTH. THE 00Z KPIT SOUNDING MEASURED 180 KTS AT ROUGHLY
230-MB WHICH MAY BE ONE OF THE STRONGER JETS OF THE SEASON SO FAR.
FURTHER TO OUR NORTH...A MID-LEVEL 500-MB JET ROUNDING THE BASE OF
AN UPPER TROUGH ACROSS EASTERN ONTARIO IS ALSO PROVIDING A
GLANCING BLOW WITH THE FCST AREA BECOMING MORE IN LINE WITH THE
RIGHT ENTRANCE REGION OF THIS MID-LEVEL FEATURE. AND IF THAT WERE
NOT ENOUGH...SFC FIELDS FROM THE RUC AND MSAS INDICATE A WEAK PRE-
FRONTAL TROUGH AND MID-LEVEL VORT MAX APPROACHING FROM EASTERN OH.
SO WHAT DOES THIS MEAN...WELL WE CAN EXPECT SNOW TO CONTINUE
DEVELOPING OVERNIGHT AS MAIN COLD FRONT CONTINUES TO APPROACH.
LATEST LOOK STILL SHOWS THE FRONT RESIDING TO THE WEST OF BUFFALO
THIS EVENING WITH A NOTABLE TEMP INCREASE DETECTED DOWNSTREAM
ACROSS OUR AREA. IN FACT...SEVERAL SITES HAVE SEEN A SLIGHT
INCREASE IN TEMPS AS PRE-FRONTAL THERMAL RIDGING MOVES OVERHEAD.
WILL HOLD OFF ON MAKING ANY WHOLESALE CHANGES TO OVERNIGHT LOWS AS
COLD AIR ADVECTION FOLLOWING FROPA WILL ALLOW TEMPS TO COOL
APPROPRIATELY. FOLLOWING FROPA...WINDS WILL BECOME ALIGNED ON A
NORTHWESTERLY CONFIGURATION WHICH COMBINED WITH 850-MB TEMPS
DROPPING TO NEAR -14C BY 12Z TUE...WILL RESULT IN DEVELOPING LAKE
EFFECT SNOWS SOUTHEAST OF LAKE ONTARIO. WITH FLOW EXPECTED TO BE
FAIRLY CHAOTIC IN NATURE...DEVELOPING BANDS WILL BE ON THE MOVE
FOR A GOOD PORTION OF THE EARLY MORNING HRS WHICH SHOULD KEEP
ACCUMULATIONS IN CHECK. NO ADDITIONAL CHANGES NEEDED FOR THE TIME
BEING.
7 PM UPDATE...
ONLY REAL CHANGE REQUIRED WAS TO DELAY SNOW INITIATION TIME AS
MAIN COLD FRONT IS STILL POSITIONED ACROSS SOUTH-CENTRAL ONTARIO
THIS HR. UPSTREAM RADAR TRENDS FROM KBUF BEGINNING TO SHOW SNOW
SHOWER DEVELOPMENT ACROSS THE WESTERN SOUTHERN TIER WITH OLEAN NOW
REPORTING LGT SNOW. THIS ACTIVITY APPEARS TO BE FROM A PRE-FRONTAL
TROUGH MOVING EAST AHEAD OF THE PRIMARY FRONT. ALOFT...LATEST
WATER VAPOR IMAGERY SHOWING VERY LITTLE SUPPORT ALOFT AS MAIN
SHORTWAVE ENERGY LAGGING WELL TO THE WEST ACROSS EASTERN LAKE
HURON. AS WE PROGRESS THROUGH THE OVERNIGHT...EXPECT SNOW SHWR
ACTIVITY TO INCREASE IN COVERAGE AS AFOREMENTIONED FRONT AND PRE-
FRONTAL TROUGH SHIFT EAST WITH TIME. FOLLOWING THEIR PASSAGE...
LOW-LEVEL FLOW WILL BECOME ALIGNED TO SUPPORT DEVELOPING LAKE
EFFECT ACROSS THE NORTHERN CWA WHERE A FEW INCHES OF NEW SNOW WILL
BE POSSIBLE BY MORNING. ASIDE FROM THAT...NO SIGNIFICANT CHANGES
REQUIRED AT THIS TIME.
PREVIOUS NEAR TERM DISCUSSION...
AT 4 PM...MID/HIGH LEVEL CLOUDS CONTINUE STREAMING ACROSS THE AREA
UNDER SOUTHWEST FLOW. AFTERNOON TEMPS ARE CURRENTLY IN THE UPPER
20S TO MID 30S.
SKIES WILL BECOME CLOUDY THIS EVENING AS A SFC TROF OVER SOUTHERN
ONTARIO APPROACHES THE AREA WHILE MOISTURE ALSO INCREASES FROM THE
SOUTH DUE TO A SYSTEM IN THE SOUTHERN PLAINS. AS THE SFC TROF
STARTS DROPPING SOUTH THROUGH THE AREA LATER THIS EVENING LOW
LEVEL FLOW WILL ALSO BECOME FAVORABLE FOR LAKE ENHANCEMENT.
SHORTLY AFTER MIDNIGHT WENT WITH LIKELY POPS ACROSS THE FAR NRN
CWA AND WITH LOW LEVEL FLOW CONTINUING TO VEER BAND OF HEAVIER
ACTIVITY WILL CONTINUE DROPPING SOUTH THROUGH DAYBREAK. DUE TO
BAND SHIFTING SOUTH WITH TIME, SNOW ACCUMS WILL REMAIN FAIRLY
MINOR WITH 1 TO 3 INCHES POSSIBLE ACROSS ONONDAGA, MADISON AND
ONEIDA COUNTIES. FOR THE REST OF THE REGION JUST SCATTERED SNOW
SHOWERS AND FLURRIES ARE EXPECTED WITH ACCUMS WELL LESS THAN AN
INCH. OVERNIGHT LOWS WILL RANGE IN THE 20S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...FOLLOWING THE FRONT, NORTHWEST FLOW WILL PERSIST OVER
THE REGION WITH SCATTERED SNOW SHOWERS CONTINUING OVER CENTRAL
NY UNDER 300/310 LOW LEVEL FLOW. ABUNDANT LOW LEVEL MOISTURE AND
COLD AIR ADVECTION WILL BRING PLENTY OF CLOUDS AND TEMPS WILL
STRUGGLE TO RISE JUST A FEW DEGREES FROM THE OVERNIGHT LOWS.
TUESDAY NIGHT...LOW LEVEL FLOW WILL BACK IN RESPONSE TO NEXT SFC
TROF DROPPING SOUTH FROM CANADA. ANY LINGERING SNOW SHOWERS WILL
LIFT NORTH AND WEAKEN DURING THE EVENING HOURS. TOWARD DAYBREAK
SFC TROF WILL EXTEND ACROSS LAKE ONTARIO BRINGING A FAVORABLE
FLOW FOR THE EASTERN SHORE INTO NORTHERN ONEIDA COUNTY. WILL
INCREASE POPS HERE TO LIKELY TOWARD DAYBREAK.
WEDNESDAY...SFC TROF WILL SWING THROUGH AREA DURING THE MORNING
HOURS WITH SFC HIGH PRES NOSING DOWN FROM EASTERN CANADA BY
AFTERNOON. LOW LEVEL FLOW LOOKS FAVORABLE FOR LES ACROSS NRN CWA
THROUGH MID MORNING WITH POSSIBLE GEORGIAN BAY CONNECTION BUT
WITH FLOW CONTINUING TO VEER THIS SHOULD LIMIT SNOW ACCUM. BY
AFTERNOON, 310 LOW LEVEL FLOW WILL KEEP THE MOST PERSISTENT SNOW
SHOWERS ACROSS THE FINGER LAKES AND NORTHERN SUSQUEHANNA REGION.
WED NIGHT/THURSDAY...ANOTHER SYSTEM MOVING THROUGH SOUTHERN CANADA
WILL BACK LOW LEVEL FLOW PUSHING ANY LINGERING SNOW SHOWERS ACROSS
CNTRL NY NORTH WHILE WEAKENING. ON THURSDAY, SFC TROF WILL
CROSS NEARBY SOUTHERN ONTARIO BY LATE DAY BRINGING THE CHC FOR
SNOW SHOWERS PRIMARILY IN THE NRN/WRN FA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
130 PM UPDATE...
FAIRLY QUIET EXTENDED PERIOD WITH A FEW SHOTS AT LIGHT SNOWS BUT
NO MAJOR STORMS IN THE OFFERING. FIRST SHOT AT SNOW COMES THURSDAY
NIGHT INTO FRIDAY WITH A COLD FRONT AND REINFORCING SHOT OF COLD
AIR. A FEW DAYS AGO THIS COLD PUSH WAS MUCH MORE IMPRESSIVE BUT IT
NOW LOOKS LIKE THE CORE WILL STAY TO OUR NORTH INTO QUEBEC. STILL
850 TEMPS ON BOTH THE GFS AND EURO ARE IN THE MID TEENS BELOW ZERO
WHICH WILL KEEP HIGHS IN THE 20S/NIGHTTIME LOWS IN THE TEENS WITH
SOME SINGLE DIGITS POSSIBLE OVER OUR COLDER SECTIONS TO THE EAST.
DESPITE NORTHWEST WINDS A SHOT OF LAKE EFFECT DOES NOT LOOK OVERLY
IMPRESSIVE WITH DRY AIR BEING THE MAIN NEGATING FACTOR. BOTH THE
GFS AND EURO SUGGEST TEMPS WARM UP A BIT SATURDAY...BEFORE ANOTHER
SYSTEM BRINGS US LIGHT SNOW SATURDAY NIGHT INTO SUNDAY...WITH MORE
SEASONABLE AIR.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
630 PM UPDATE...
VFR CONTINUES BUT IT WONT LAST WITH MOISTURE COMING IN FROM THE
WSW AND A COLD FRONT DROPPING SE FROM ONTARIO THIS EVENING. MVFR
CIGS AS CLOSE AS THE LAKE PLAIN AT FULTON AND ROCHESTER. BY 5Z
MVFR CIGS AND VSBYS IN LIGHT SNOW WILL BE ACROSS THE NY SITES.
KAVP WILL REMAIN VFR THROUGH TUESDAY.
SNOW SHOWER COVERAGE WILL PEAK 6 TO 9Z WITH THE FRONT. IFR VSBY
POSSIBLE DURING THIS TIME AT RME AND SYR. AFTER THAT LAKE EFFECT
WILL KICK IN KEEPING THE MVFR GOING INTO TUE MORNING. AROUND 15Z
SOME IMPROVEMENT BUT WITH NW FLOW SYR MAY BE IN MVFR ALL DAY. REST
OF NY SITES MAY BE IN AND OUT OF MVFR DURING THE AFTN. INVERSION
LEVEL...MOISTURE AND DENDRITE LAYERS LOWER DURING THE AFTN SO THE
SNOW SHOWERS WILL DIMINISH IN INTENSITY AND COVERAGE.
SW FLOW AT 5 TO 10 KTS SHIFTING TO W AROUND 5Z...THEN NW AT 10 KTS
LATE TONIGHT THROUGH TUESDAY.
OUTLOOK...
TUE NGT TO WED NGT...OCCASIONAL MVFR/IFR FOR NY TERMINALS IN SNOW
SHOWERS.
THU THROUGH SAT...MAINLY VFR. RESTRICTIONS ARE POSSIBLE AT
KRME/KSYR IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM
NEAR TERM...CMG/RRM
SHORT TERM...RRM
LONG TERM...HEDEN
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS PORTLAND OR
823 PM PST SAT DEC 29 2012
.SYNOPSIS...A WEAK DISTURBANCE IS MOVING SOUTH THROUGH THE FORECAST
AREA THIS EVENING. DRIER WEATHER IS EXPECTED LATE TONIGHT AND SUNDAY
AS AN UPPER LEVEL RIDGE BUILDS IN. A SPLITTING TROUGH WILL APPROACH
MONDAY FOLLOWED BY ANOTHER UPPER RIDGE TUESDAY. OFFSHORE GRADIENTS
WILL GRADUALLY INTENSIFY NEXT WEEK RESULTING IN AN EXTENDED PERIOD OF
EAST WIND THROUGH THE COLUMBIA RIVER GORGE.
&&
.SHORT TERM...SATELLITE IMAGERY SHOWS A WEAK DISTURBANCE ENHANCING
THE CLOUDS OVER SOUTHWEST WASHINGTON/NORTHWEST OREGON THIS EVENING.
THIS FEATURE IS MOVING SOUTHWARD THROUGH THE AREA THIS EVENING.
DOPPLER RADAR AND SURFACE OBSERVATIONS SHOWS VERY LIGHT SHOWERS OVER
THE NORTHERN HALF OF THE AREA. BY 12Z SUN HIGH PRESSURE CENTERED AT
130W STRENGTHENS IN RESPONSE TO THE DEEP LOW OUT AROUND 150W. EXPECT
CLOUDS TO DIMINISH FROM THE NORTH OVERNIGHT.
SUNDAY WILL BE DRY AS THE UPPER LEVEL RIDGE AXIS GETS CLOSER TO THE
COAST. EXPECT WEAK OFFSHORE SURFACE FLOW TO CONTINUE SUNDAY. GRADIENT
SHOULD INCREASE A LITTLE MORE SUN NIGHT WITH WIDESPREAD FREEZING
TEMPS. SUN NIGHT SHOULD BE THE COLDEST NIGHT OF THE SEASON SO FAR IN
MANY AREAS. MODELS GOING WITH UPPER TEENS IN SPOTS LIKE KHIO AND 20
AT KEUG. CLEAR SKIES AND COLD TEMPERATURES SHOULD PRODUCE PATCHY
FREEZING FOG IN THE INTERIOR VALLEYS SUN NIGHT. HOWEVER...AIR MASS
MAY BE COLD AND DRY ENOUGH TO INHIBIT MUCH FOG FORMATION.
ANOTHER SPLITTING TROUGH APPROACHES THE COAST MON
MORNING...STRETCHING APART JUST OFFSHORE MON...WITH THE MAIN ENERGY
DIVING SOUTH ALONG THE NRN CA COAST. PRECIP SEEMS LIMITED TO THE
COASTAL WATERS AND COASTAL STRIP. HIGH PRESSURE ALOFT STRENGTHENS
AGAIN MON NIGHT AS DOES THE OFFSHORE SURFACE GRADIENT. EXPECT ANOTHER
COLD NIGHT WITH SOME VALLEY LOCATIONS GETTING CLOSE TO 20 DEGREES.
LIKENS
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...UPPER LEVEL
RIDGE IN PLACE TUESDAY AND WEDNESDAY WILL PROVIDE DRY
WEATHER...THOUGH FAVORABLE CONDITIONS FOR VALLEY FOG BOTH MORNINGS.
THE EXCEPTION WILL BE ON THE WEST SIDE OF THE GORGE WHERE EASTERLY
WINDS SHOULD STAY HIGH ENOUGH TO PREVENT ANY FOG FORMATION. BY LATE
WEDNESDAY MODEL AGREEMENT DEGRADES AS A CUT OFF LOW PRESSURE SYSTEM
MOVES TOWARD THE PAC NW...AND THE MODELS STRUGGLE WITH WHERE THIS
FEATURE WILL ULTIMATELY GO. CURRENTLY THEY ARE IN GOOD AGREEMENT ON
TIMING...AND DEPICT THE LOW MOVING ONSHORE LATE THURSDAY.
HOWEVER...THE MODELS BRING IT INLAND ANYWHERE FROM NORTHERN
CALIFORNIA TO NORTHERN WASHINGTON. DUE TO THIS UNCERTAINTY...DID NOT
MAKE MAJOR CHANGES TO THE PREVIOUS FORECAST...BUT DID TREND TOWARD
THE ECMWF MODEL PER NATIONAL AND INTERSITE COORDINATION/MODEL
PREFERENCE. THE ECMWF SOLUTION IS THE MORE SOUTHERLY TRACK...BRINGING
THE LOW ONSHORE IN NORTHERN CALIFORNIA AND KEEPING THE PAC NW FAIRLY
DRY THROUGH THE EXTENDED PERIOD. TEMPERATURES LOOK TO BE NEAR NORMAL
FROM THURSDAY ONWARD. BURGESS
&&
.AVIATION....SHORT WAVE DROPPING SOUTH OUT OF WESTERN WA BRINGING
SHOWERS MAINLY OVER THE NORTHERN INLAND AREAS THIS EVENING.
RADAR LOOP SHOWS TAIL END OF SHOWERS JUST ABOUT TO MOVE OUT OF SW
WA INTO OREGON. SATELLITE SHOW A SIMILAR TREND WITH COLDER CLOUD
TOPS MOVING OUT OF SW WA TO REVEAL LOWER CLOUDS BELOW. SFC OBS
INDICATING LOW MVFR TO IFR CONDITIONS WITH A FEW SHOWERS STILL COMING
FROM THE LOWER CLOUD LAYER. TAKING A LOOKS AT NAM BUFR SOUNDINGS IT
WILL TAKE A WHILE FOR CONDITIONS TO IMPROVE...ESPECIALLY INLAND.
THE 00Z NAM BUFR SOUNDINGS KEEP IFR TO LOW MVFR CIGS AT INLAND TAF
SITES THROUGH ABOUT 14Z-18Z SUN. THE 00Z RUC SOUNDINGS SUGGEST MORE
OF A LOW MVFR THROUGH THAT SAME TIME PERIOD AND WILL LIKELY TREND
FCST TOWARD THE RUC SOLN. AIR MASS DRYING AS OFFSHORE FLOW
STRENGTHENS FOR MAINLY VFR CONDITIONS LATER SUN MORNING AND
AFTERNOON.
KPDX AND APPROACHES...MVFR CIGS PREVAILING TONIGHT WITH IFR CIGS
POSSIBLE THROUGH ABOUT 14Z. CONFIDENCE NOT HIGH ENOUGH TO INCLUDE
IFR IN THE 06Z TAF PACKAGE BUT WILL INCLUDE A SCATTERED LAYER FOR
THE OVERNIGHT HOURS.
&&
.MARINE...LONG-PERIOD SWELL TRAIN OVER THE COASTAL WATERS IS
BEGINNING TO DIMINISH AND WILL DROP BELOW 10 FT AFTER MIDNIGHT.
WEAK HIGH PRES BUILDS OFFSHORE THROUGH EARLY SUNDAY...BUT THAT IS
SHORT LIVED AS ANOTHER WEAKENING FRONT APPROACHES THE WATERS SUN
NIGHT INTO MONDAY. HIGH PRES RETURNS AGAIN TUES BEFORE ANOTHER
SPLITTING SYSTEM ARRIVES LATE WED. NO REAL WIND CONCERNS WITH
THESE FRONTS...THOUGH BEHIND EACH SUBSEQUENT FRONT SWELL PICKS
BACK UP INTO THE TEENS. TODD
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM PST
SUNDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE
OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
8 AM PST SUNDAY.
&&
$$
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 STATE COLLEGE PA
316 PM EST SUN DEC 30 2012
.SYNOPSIS...
A TROUGH IS FORECAST TO PERSIST OVER THE EASTERN UNITED STATES FOR
THE NEXT WEEK. THIS WILL KEEP THE MAIN STORM TRACK SUPPRESSED TO
OUR SOUTH. A SURGE OF ARCTIC AIR AND A WEAK WAVE COULD BRING SNOW
SHOWERS TO WESTERN AREAS NEW YEARS EVE. BEHIND THIS SYSTEM THE
ARCTIC FRONT COULD PUSH INTO PENNSYLVANIA ON NEW YEARS DAY AND
INTO WEDNESDAY. GENERALLY COLD PATTERN WITH NO BIG STORMS FORECAST.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
UPDATED GRIDS HAD TO PAINT IN THE BIG SNOW BAND THAT FORMED...SO
MUCH FOR THINGS DISSIPATING. BIG SNOW BAND WITH SOME STEADY SNOW
AND ACCUMULATING SNOW EXTENDS ACROSS PORTIONS OF
ELK...CLEARFIELD...CENTRE AND HUNTINGDON COUNTIES. MAY CLIP
NORTHERN BLAIR TOO. A FEW LOCATIONS COULD GET OVER AN INCH OF SNOW
FROM THIS. FOLLOWING THIS BETTER WITH SPECIAL WEATHER STATEMENTS.
AFFECTING PARTS OF I-80 AND I-99.
WE LET THE ADVISORY FOR THE SNOW IN THE SOUTHWEST EXPIRE. THOUGHT
THING WOULD WIND DOWN. BUT CLEARLY WE HAVE LINGERING STRONGER SNOW
SQUALL ISSUES THAN PREVIOUSLY THOUGHT OR INDICATED BY GUIDANCE.
EXTENDED SNOW PROBS WITH THIS BAND AND ANY OTHERS THROUGH 8 PM.
THERE IS ANOTHER NOTABLE BAND OVER LYCOMING AND CLINTON
COUNTIES...MUCH WEAKER BUT THAT COULD BE A FUNCTION OF REALITY AND
DISTANCE FROM THE RADAR. WE COULD BE OVERSHOOTING SOME OF IT. SO
AFTER 22-00Z EXPECT THINGS TO BE IMPROVING...S L O W L Y.
THE WINDS STILL STRONG BUT SHOULD BEGIN TO SLIDE BELOW POTENTIAL
TO REACH ADVISORY CATEGORY LEVELS. WE HAD TWO LOCATIONS REACH
MINIMAL VALUES FOR WINDS OR WIND GUSTS EARLIER TODAY.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH TUESDAY/...
GUIDANCE SHOWS SNOW SHOWER ACTIVITY REALLY DROPPING OFF FAST. THE
NORTHWEST WINDS SLOWLY BECOME MORE WNW OVERNIGHT. THIS CAUSES THE
13KM RAP TO PRODUCE MORE ALONG LAKE ERIE BANDS WHICH SHOULD REDUCE
SNOW SHOWERS IN SOUTHWESTERN MOUNTAINS AND GRADUALLY OVER WARREN
AND MCKEAN COUNTY. MOST SNOW SHOULD CEASE. THERE IS A SIMILAR
TREND IN THE 4KM NAM IMPLIED SNOW-BANDS. THERE IS VIRTUALLY NOW
ACCUMULATING QPF IN PA IN THESE MODELS MUCH AFTER 21Z...SO THIS
PERIOD SHOULD BE RELATIVELY DRY TO START.
WINDS CONTINUE TO DIMINISH OVERNIGHT. A SLOW PROCESS AND THE
CLOUDS ARE SLOW TO DISSIPATE.
ON NEW YEARS DAY A NORTHERN STREAM WAVE AND ITS COLD FRONT WILL
ALLOW A SURGE OF WEAK WARM ADVECTION OVER THE RIDGE AND AHEAD OF
THE FRONT. THE MODELS AND ENSEMBLES IMPLY A POTENTIAL SURGE OF
LIGHT SNOW AHEAD OF THE SYSTEM LATE NEW YEARS EVE INTO EARLY NEW
YEARS. SNOW WOULD BE VERY LIGHT AND AT THIS TIME CONFINED TO
WESTERN AREAS. SHOWED SOME POPS LATER AFTERNOON AND EVENING AS
SNOW IN WESTERNMOST AREAS. THIS LOOKS VERY WEAK AND VERY LIGHT.
THE COLD AIR BEHIND THIS SYSTEM PUSHES SOME -20 TO -24C AIR INTO
THE NORTHEASTERN US..ARCTIC AIR...WITH THE -12 TO -15C CONTOURS
GETTING INTO PA DURING THE AFTERNOON TUESDAY. SOME VERY COLD AIR
WILL CLIP OUR AREA FOR A CHILLING START TO THE NEW YEAR.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
LATEST MED RANGE GUIDANCE CONTINUES TO BACK OFF ON THE
MAGNITUDE/COLDNESS OF THE AIR MASS MOVING INTO THE NERN U.S. THIS
WEEK. THUS...HAVE BUMPED UP THE TEMPS SLIGHTLY FOR THE LONG TERM.
BUT THE NW FLOW CONTINUES...AND NOTHING ELSE WAS CHANGED WITH THE
OVERNIGHT PKG. PREV DISC FOLLOWS...
LAKE ENHANCED BANDS SHOULD CONTINUE THROUGH WEDNESDAY
MORNING...AND PERHAPS WEDNESDAY AFTERNOON. A FEW NORTHERN STREAM
FEATURES WILL CROSS THE LOWER GREAT LAKES AROUND MID-WEEK AND MAKE
LAKE EFFECT SHOWERS. AN ARCTIC AIR MASS BEGINS TO MOVE THROUGH
SOUTHERN CANADA AND DECREASING 850MB TEMPERATURES WILL CONTINUE
THROUGH THE LATTER HALF OF THE WEEK. CURRENT RUNS HAVE PA UNDER
M16C TEMPERATURES AT 850MB THURSDAY MORNING. THE GFS AND EC
PROPAGATE ANOTHER TROUGH THROUGH PENNSYLVANIA FRIDAY. THE EC
SPEEDS UP THIS TROUGH AS THE GFS SLOWS THE SYSTEM DOWN. THE
MOVEMENT OF THE LARGE UPPER LEVEL LOW DRIVING THIS SUCCESSIVE
SHORT WAVE TROUGHS VARIES BETWEEN THE MODELS. THE EC MOVES IT
QUICKER THROUGH NOVA SCOTIA AND THEN EXITING TO THE NORTHEAST. THE
GFS SLOWS IT DOWN ON A MORE EASTERLY TRACK. EITHER WAY...EXPECT
HIGH TEMPERATURES THIS WEEK TO BE AT OR BELOW FREEZING...MONDAY
AND TUESDAY BEING THE WARMEST DAYS. HIGHS AFTER THE TROUGH PASSAGE
INTO TUESDAY WILL HAVE HIGHS IN THE UPPER TEENS BY THE END OF THE
UP COMING WEEK. COUPLE THE LOW TEMPS WITH THE GUSTY FLOW...AND
WIND CHILLS COULD BE AN ISSUE DURING THIS TIME FRAME. LOWS THROUGH
THE LATER HALF OF THE WEEK SHOULD BE IN THE LOW TEENS.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
NWRLY UPSLOPE FLOW WILL KEEP IFR/MVFR CONDS AND SCTD SHSN ACROSS
THE NW MTNS AND LAUREL HIGHLANDS INTO THIS EVENING. VFR TO
OCCASIONALLY MVFR IN -SHSN AT THE CENTRAL MTN TERMINALS /AOO AND
UNV/. FARTHER EAST...CONDS HAVE RETURNED TO VFR...WITH EVEN SOME
BREAKS IN THE OVC.
BLUSTERY NW WINDS WILL GRADUALLY BEGIN TO DIMINISH THIS EVE.
HOWEVER...OCCASIONAL GUSTS OVER 30 MPH REMAIN POSSIBLE UNTIL
THEN.
LINGERING SHSN ACTIVITY SHOULD TAPER OFF OVERNIGHT...ALTHOUGH
SOME LOW CLOUDS MAY LINGER ACROSS THE WEST.
CONDS IMPROVE ON AREA-WIDE MONDAY...AS HIGH PRESSURE BRIEFLY
BUILDS INTO THE REGION.
OUTLOOK...
MON...VFR EAST...BECOMING VFR WEST.
MON NIGHT-TUES...SOME MVFR POSS...WITH -SHSN POSS.
WED-THU...GENERALLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM/DANGELO
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...DANGELO/CERU
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
250 PM EST SUN DEC 30 2012
.SYNOPSIS...
A TROUGH IS FORECAST TO PERSIST OVER THE EASTERN UNITED STATES FOR
THE NEXT WEEK. THIS WILL KEEP THE MAIN STORM TRACK SUPPRESSED TO
OUR SOUTH. A SURGE OF ARCTIC AIR AND A WEAK WAVE COULD BRING SNOW
SHOWERS TO WESTERN AREAS NEW YEARS EVE. BEHIND THIS SYSTEM THE
ARCTIC FRONT COULD PUSH INTO PENNSYLVANIA ON NEW YEARS DAY AND
INTO WEDNESDAY. GENERALLY COLD PATTERN WITH NO BIG STORMS FORECAST.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
UPDATED GRIDS HAD TO PAINT IN THE BIG SNOW BAND THAT FORMED...SO
MUCH FOR THINGS DISSIPATING. BIG SNOW BAND WITH SOME STEADY SNOW
AND ACCUMULATING SNOW EXTENDS ACROSS PORTIONS OF
ELK...CLEARFIELD...CENTRE AND HUNTINGDON COUNTIES. MAY CLIP
NORTHERN BLAIR TOO. A FEW LOCATIONS COULD GET OVER AN INCH OF SNOW
FROM THIS. FOLLOWING THIS BETTER WITH SPECIAL WEATHER STATEMENTS.
AFFECTING PARTS OF I-80 AND I-99.
WE LET THE ADVISORY FOR THE SNOW IN THE SOUTHWEST EXPIRE. THOUGHT
THING WOULD WIND DOWN. BUT CLEARLY WE HAVE LINGERING STRONGER SNOW
SQUALL ISSUES THAN PREVIOUSLY THOUGHT OR INDICATED BY GUIDANCE.
EXTENDED SNOW PROBS WITH THIS BAND AND ANY OTHERS THROUGH 8 PM.
THERE IS ANOTHER NOTABLE BAND OVER LYCOMING AND CLINTON
COUNTIES...MUCH WEAKER BUT THAT COULD BE A FUNCTION OF REALITY AND
DISTANCE FROM THE RADAR. WE COULD BE OVERSHOOTING SOME OF IT. SO
AFTER 22-00Z EXPECT THINGS TO BE IMPROVING...S L O W L Y.
THE WINDS STILL STRONG BUT SHOULD BEGIN TO SLIDE BELOW POTENTIAL
TO REACH ADVISORY CATEGORY LEVELS. WE HAD TWO LOCATIONS REACH
MINIMAL VALUES FOR WINDS OR WIND GUSTS EARLIER TODAY.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH TUESDAY/...
GUIDANCE SHOWS SNOW SHOWER ACTIVITY REALLY DROPPING OFF FAST. THE
NORTHWEST WINDS SLOWLY BECOME MORE WNW OVERNIGHT. THIS CAUSES THE
13KM RAP TO PRODUCE MORE ALONG LAKE ERIE BANDS WHICH SHOULD REDUCE
SNOW SHOWERS IN SOUTHWESTERN MOUNTAINS AND GRADUALLY OVER WARREN
AND MCKEAN COUNTY. MOST SNOW SHOULD CEASE. THERE IS A SIMILAR
TREND IN THE 4KM NAM IMPLIED SNOW-BANDS. THERE IS VIRTUALLY NOW
ACCUMULATING QPF IN PA IN THESE MODELS MUCH AFTER 21Z...SO THIS
PERIOD SHOULD BE RELATIVELY DRY TO START.
WINDS CONTINUE TO DIMINISH OVERNIGHT. A SLOW PROCESS AND THE
CLOUDS ARE SLOW TO DISSIPATE.
ON NEW YEARS DAY A NORTHERN STREAM WAVE AND ITS COLD FRONT WILL
ALLOW A SURGE OF WEAK WARM ADVECTION OVER THE RIDGE AND AHEAD OF
THE FRONT. THE MODELS AND ENSEMBLES IMPLY A POTENTIAL SURGE OF
LIGHT SNOW AHEAD OF THE SYSTEM LATE NEW YEARS EVE INTO EARLY NEW
YEARS. SNOW WOULD BE VERY LIGHT AND AT THIS TIME CONFINED TO
WESTERN AREAS. SHOWED SOME POPS LATER AFTERNOON AND EVENING AS
SNOW IN WESTERNMOST AREAS. THIS LOOKS VERY WEAK AND VERY LIGHT.
THE COLD AIR BEHIND THIS SYSTEM PUSHES SOME -20 TO -24C AIR INTO
THE NORTHEASTERN US..ARCTIC AIR...WITH THE -12 TO -15C CONTOURS
GETTING INTO PA DURING THE AFTERNOON TUESDAY. SOME VERY COLD AIR
WILL CLIP OUR AREA FOR A CHILLING START TO THE NEW YEAR.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LATEST MED RANGE GUID BACKS OFF ON THE MAGNITUDE/COLDNESS OF THE
AIR MASS MOVING INTO THE NERN U.S. THIS WEEK. THUS...HAVE BUMPED
UP THE TEMPS SLIGHTLY FOR THE LONG TERM. BUT THE NW FLOW
CONTINUES...AND NOTHING ELSE WAS CHANGED WITH THE OVERNIGHT PKG.
PREV DISC FOLLOWS...
LAKE ENHANCED BANDS SHOULD CONTINUE THROUGH WEDNESDAY
MORNING...AND PERHAPS WEDNESDAY AFTERNOON. A FEW NORTHERN STREAM
FEATURES WILL CROSS THE LOWER GREAT LAKES AROUND MID-WEEK AND MAKE
LAKE EFFECT SHOWERS. AN ARCTIC AIR MASS BEGINS TO MOVE THROUGH
SOUTHERN CANADA AND DECREASING 850MB TEMPERATURES WILL CONTINUE
THROUGH THE LATTER HALF OF THE WEEK. CURRENT RUNS HAVE PA UNDER
M16C TEMPERATURES AT 850MB THURSDAY MORNING. THE GFS AND EC
PROPAGATE ANOTHER TROUGH THROUGH PENNSYLVANIA FRIDAY. THE EC
SPEEDS UP THIS TROUGH AS THE GFS SLOWS THE SYSTEM DOWN. THE
MOVEMENT OF THE LARGE UPPER LEVEL LOW DRIVING THIS SUCCESSIVE
SHORT WAVE TROUGHS VARIES BETWEEN THE MODELS. THE EC MOVES IT
QUICKER THROUGH NOVA SCOTIA AND THEN EXITING TO THE NORTHEAST. THE
GFS SLOWS IT DOWN ON A MORE EASTERLY TRACK. EITHER WAY...EXPECT
HIGH TEMPERATURES THIS WEEK TO BE AT OR BELOW FREEZING...MONDAY
AND TUESDAY BEING THE WARMEST DAYS. HIGHS AFTER THE TROUGH PASSAGE
INTO TUESDAY WILL HAVE HIGHS IN THE UPPER TEENS BY THE END OF THE
UP COMING WEEK. COUPLE THE LOW TEMPS WITH THE GUSTY FLOW...AND
WIND CHILLS COULD BE AN ISSUE DURING THIS TIME FRAME. LOWS THROUGH
THE LATER HALF OF THE WEEK SHOULD BE IN THE LOW TEENS.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
NWRLY UPSLOPE FLOW WILL KEEP IFR/MVFR CONDS AND SCTD SHSN ACROSS
THE NW MTNS AND LAUREL HIGHLANDS INTO THIS EVENING. VFR TO
OCCASIONALLY MVFR IN -SHSN AT THE CENTRAL MTN TERMINALS /AOO AND
UNV/. FARTHER EAST...CONDS HAVE RETURNED TO VFR...WITH EVEN SOME
BREAKS IN THE OVC.
BLUSTERY NW WINDS WILL GRADUALLY BEGIN TO DIMINISH THIS EVE.
HOWEVER...OCCASIONAL GUSTS OVER 30 MPH REMAIN POSSIBLE UNTIL
THEN.
LINGERING SHSN ACTIVITY SHOULD TAPER OFF OVERNIGHT...ALTHOUGH
SOME LOW CLOUDS MAY LINGER ACROSS THE WEST.
CONDS IMPROVE ON AREA-WIDE MONDAY...AS HIGH PRESSURE BRIEFLY
BUILDS INTO THE REGION.
OUTLOOK...
MON...VFR EAST...BECOMING VFR WEST.
MON NIGHT-TUES...SOME MVFR POSS...WITH -SHSN POSS.
WED-THU...GENERALLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR PAZ024>026-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...GRUMM/DANGELO
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...DANGELO/CERU
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
108 PM EST SUN DEC 30 2012
.SYNOPSIS...
A TROUGH IS FORECAST TO PERSIST OVER THE EASTERN UNITED STATES FOR
THE NEXT WEEK. THIS WILL KEEP THE MAIN STORM TRACK SUPPRESSED TO
OUR SOUTH. A SURGE OF ARCTIC AIR AND A WEAK WAVE COULD BRING SNOW
SHOWERS TO WESTERN AREAS NEW YEARS EVE. BEHIND THIS SYSTEM THE
ARCTIC FRONT COULD PUSH INTO PENNSYLVANIA ON NEW YEARS DAY AND
INTO WEDNESDAY. GENERALLY COLD PATTERN WITH NO BIG STORMS FORECAST.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
LETTING THE ADVISORY FOR THE SNOW IN THE SOUTHWEST GRACEFULLY
EXPIRE. SNOW SHOWERS CONTINUE OVER THE REGION THIS AFTERNOON. BUT
MODELS SUGGEST THE ORIENTATION OF THE BANDS WILL CHANGE AS THE
WINDS BEGIN TO BECOME MORE WESTERLY ALOFT. MODEL SOUNDINGS ALSO
SHOW A GENERAL TREND TO MORE STABLE CONDITIONS. AN INVERSION IS
NOW PRESENT AND SHOULD LOWER OVER THE NEXT 3-6 HOURS HELPING
DECREASE THE ACTIVITY. EXPECT MOST SNOW SHOWERS TO END AROUND 20Z
BUT LINGER LONGER IN THE SW MOUNTAINS AND WARREN COUNTY AREA.
MOST AREAS WILL SEE SOME LIGHT FLURRIES WITH LIMITED ACCUMULATING
SNOW. SOUTHEAST AREAS AT BEST MIGHT SEE A FLURRY OR TOO. BUT
CHANCES ARE DIMINISHING. CLOUDS WILL HANG TOUGH WITH BEST PEAKS OF
SUN OVER SOUTHEAST. YORK COUNTY CURRENTLY LOOKS BEST FOR SOME SUN
AT TIMES BUT MOST OF SOUTHEAST IS IMPROVING...S L O W L Y.
THE WINDS TOO SHOULD SLOW DIMINISH AND WILL LET THE ADVISORY
GRACEFULLY EXPIRE IN ABOUT 2 HOURS. WE HAD AT LEAST ONE REPORT OF
SUSTAINED WINDS OF OR OVER 27KTS (KMDT) EARLIER TODAY. WINDS
SHOULD BE ON THE DOWN TICK IN OVER THE NEXT 2-4 HOURS. STILL SOME
GUSTS EARLY TONIGHT BUT ALL SHOULD BE SUB-ADVISORY.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH TUESDAY/...
GUIDANCE SHOWS SNOW SHOWER ACTIVITY REALLY DROPPING OFF FAST. THE
NORTHWEST WINDS SLOWLY BECOME MORE WNW OVERNIGHT. THIS CAUSES THE
13KM RAP TO PRODUCE MORE ALONG LAKE ERIE BANDS WHICH SHOULD REDUCE
SNOW SHOWERS IN SOUTHWESTERN MOUNTAINS AND GRADUALLY OVER WARREN
AND MCKEAN COUNTY. MOST SNOW SHOULD CEASE. THERE IS A SIMILAR
TREND IN THE 4KM NAM IMPLIED SNOW-BANDS. THERE IS VIRTUALLY NOW
ACCUMULATING QPF IN PA IN THESE MODELS MUCH AFTER 21Z...SO THIS
PERIOD SHOULD BE RELATIVELY DRY TO START.
WINDS CONTINUE TO DIMINISH OVERNIGHT. A SLOW PROCESS AND THE
CLOUDS ARE SLOW TO DISSIPATE.
ON NEW YEARS DAY A NORTHERN STREAM WAVE AND ITS COLD FRONT WILL
ALLOW A SURGE OF WEAK WARM ADVECTION OVER THE RIDGE AND AHEAD OF
THE FRONT. THE MODELS AND ENSEMBLES IMPLY A POTENTIAL SURGE OF
LIGHT SNOW AHEAD OF THE SYSTEM LATE NEW YEARS EVE INTO EARLY NEW
YEARS. SNOW WOULD BE VERY LIGHT AND AT THIS TIME CONFINED TO
WESTERN AREAS. SHOWED SOME POPS LATER AFTERNOON AND EVENING AS
SNOW IN WESTERNMOST AREAS. THIS LOOKS VERY WEAK AND VERY LIGHT.
THE COLD AIR BEHIND THIS SYSTEM PUSHES SOME -20 TO -24C AIR INTO
THE NORTHEASTERN US..ARCTIC AIR...WITH THE -12 TO -15C CONTOURS
GETTING INTO PA DURING THE AFTERNOON TUESDAY. SOME VERY COLD AIR
WILL CLIP OUR AREA FOR A CHILLING START TO THE NEW YEAR.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LATEST MED RANGE GUID BACKS OFF ON THE MAGNITUDE/COLDNESS OF THE
AIR MASS MOVING INTO THE NERN U.S. THIS WEEK. THUS...HAVE BUMPED
UP THE TEMPS SLIGHTLY FOR THE LONG TERM. BUT THE NW FLOW
CONTINUES...AND NOTHING ELSE WAS CHANGED WITH THE OVERNIGHT PKG.
PREV DISC FOLLOWS...
LAKE ENHANCED BANDS SHOULD CONTINUE THROUGH WEDNESDAY
MORNING...AND PERHAPS WEDNESDAY AFTERNOON. A FEW NORTHERN STREAM
FEATURES WILL CROSS THE LOWER GREAT LAKES AROUND MID-WEEK AND MAKE
LAKE EFFECT SHOWERS. AN ARCTIC AIR MASS BEGINS TO MOVE THROUGH
SOUTHERN CANADA AND DECREASING 850MB TEMPERATURES WILL CONTINUE
THROUGH THE LATTER HALF OF THE WEEK. CURRENT RUNS HAVE PA UNDER
M16C TEMPERATURES AT 850MB THURSDAY MORNING. THE GFS AND EC
PROPAGATE ANOTHER TROUGH THROUGH PENNSYLVANIA FRIDAY. THE EC
SPEEDS UP THIS TROUGH AS THE GFS SLOWS THE SYSTEM DOWN. THE
MOVEMENT OF THE LARGE UPPER LEVEL LOW DRIVING THIS SUCCESSIVE
SHORT WAVE TROUGHS VARIES BETWEEN THE MODELS. THE EC MOVES IT
QUICKER THROUGH NOVA SCOTIA AND THEN EXITING TO THE NORTHEAST. THE
GFS SLOWS IT DOWN ON A MORE EASTERLY TRACK. EITHER WAY...EXPECT
HIGH TEMPERATURES THIS WEEK TO BE AT OR BELOW FREEZING...MONDAY
AND TUESDAY BEING THE WARMEST DAYS. HIGHS AFTER THE TROUGH PASSAGE
INTO TUESDAY WILL HAVE HIGHS IN THE UPPER TEENS BY THE END OF THE
UP COMING WEEK. COUPLE THE LOW TEMPS WITH THE GUSTY FLOW...AND
WIND CHILLS COULD BE AN ISSUE DURING THIS TIME FRAME. LOWS THROUGH
THE LATER HALF OF THE WEEK SHOULD BE IN THE LOW TEENS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NWRLY UPSLOPE FLOW WILL KEEP IFR/MVFR CONDS AND SCTD SHSN ACROSS
THE NW MTNS AND LAUREL HIGHLANDS INTO THIS EVENING. VFR TO
OCCASIONALLY MVFR IN -SHSN AT THE CENTRAL MTN TERMINALS /AOO AND
UNV/. FARTHER EAST...CONDS HAVE RETURNED TO VFR...WITH EVEN SOME
BREAKS IN THE OVC.
BLUSTERY NW WINDS WILL GRADUALLY BEGIN TO DIMINISH THIS EVE.
HOWEVER...OCCASIONAL GUSTS OVER 30 MPH REMAIN POSSIBLE UNTIL
THEN.
LINGERING SHSN ACTIVITY SHOULD TAPER OFF OVERNIGHT...ALTHOUGH
SOME LOW CLOUDS MAY LINGER ACROSS THE WEST.
CONDS IMPROVE ON AREA-WIDE MONDAY...AS HIGH PRESSURE BRIEFLY
BUILDS INTO THE REGION.
OUTLOOK...
MON...VFR EAST...BECOMING VFR WEST.
MON NIGHT-TUES...SOME MVFR POSS...WITH -SHSN POSS.
WED-THU...GENERALLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ024-033.
WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR PAZ024>026-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...GRUMM/DANGELO
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...DANGELO/CERU
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1229 PM EST SUN DEC 30 2012
.SYNOPSIS...
A TROUGH IS FORECAST TO PERSIST OVER THE EASTERN UNITED STATES FOR
THE NEXT WEEK. THIS WILL KEEP THE MAIN STORM TRACK SUPPRESSED TO
OUR SOUTH. A SURGE OF ARCTIC AIR AND A WEAK WAVE COULD BRING SNOW
SHOWERS TO WESTERN AREAS NEW YEARS EVE. BEHIND THIS SYSTEM THE
ARCTIC FRONT COULD PUSH INTO PENNSYLVANIA ON NEW YEARS DAY AND
INTO WEDNESDAY. GENERALLY COLD PATTERN WITH NO BIG STORMS FORECAST.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SNOW SHOWERS CONTINUE OVER CENTRAL PENNSYLVANIA. EAST OF THE
HIGHER TERRAIN THEY MAINLY PRODUCE A BRIEF DUSTING OF SNOW. THERE
HAS BEEN A PERSISTENT NW TO SE BAND THAT HAS EXTENDED THROUGH
STATE COLLEGE AT TIMES...BUT RECENTLY THE HIGHER ECHOES HAVE
DRIFTED NORTH. THIS FEATURE HAS PRODUCED LIGHT SNOW SHOWERS.
THERE IS STILL SOME ON GOING SNOW IN THE SW MOUNTAINS AND WILL LET
THE ADVISORY FOR 3-5 INCHES OF SNOW EXPIRE AT 18Z AS SNOW
DIMINISHES DURING THE DAY AND ACCUMULATIONS DIMINISH TOO.
STRONG WINDS AT 850 HPA...OVER 50 KTS AND A FAIRLY GOOD PRESSURE
RISE-FALL COUPLET IN 6 HOUR NAM12 AND RUC13 HAVE FAVORED A WIND
ADVISORY. IN WESTERN PA WINDS OVER 40 KTS SHOULD BE CONFINED TO
ABOUT ABOVE ABOUT 1800 FT. SOME STRONGER WINDS WITH DOWN-SLOPE
EFFECT IN SOUTHERN PA POSSIBLE TOO. GUST ALREADY IN MID-30KT RANGE
IN LOWER SUSQUEHANNA VALLEY. PUT ADVISORY ACROSS ALL OF SOUTHERN
TIER TO INCLUDE YORK-HARRISBURG AND LANCASTER AREAS. SHOULD BE
OVER LATE AFTERNOON WITH INCREASING STABILITY.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY/...
SNOW SUBSIDES IN WEST AND WINDS SLOWLY ABATE SUNDAY NIGHT. THERE
ARE HINTS OF SOME LIGHT SNOW MOVING INTO THE WESTERN AREAS LATE IN
THE AFTERNOON OR EVENING NEW YEARS EVE. AS STATE IN PREVIOUS
SHIFTS DISCUSSION...
PREVIOUS DISCUSSION....WARM ADVECTION TONIGHT WILL TRY TO CLEAR OUT THE
SKIES...BUT MESO MDLS STILL PRODUCE MEAGER QPF IN THE FAR NW.
THUS...SCT/ISOLD SHSN MAY CONTINUE FOR THE FIRST HALF OF THE
NIGHT. CLOUDS WILL BE TOUGH TO CLEAR OVER THE NRN HALF OF THE
AREA...AND HIGH CLOUDS WILL START TO ARRIVE FROM THE WEST BY
MONDAY MORNING. JET STREAM BRIEFLY RIDGES N OF THE AREA TONIGHT
AND MONDAY...BUT AN INCREASE IN SPEED WILL OCCUR MONDAY OVER THE
OHIO VALLEY AND SPREAD ACROSS THE STATE MON NIGHT. THIS WILL
TRANSPORT A LITTLE MOISTURE UP OVER THE SFC/UPPER RIDGE...BUT NOT
MUCH AT ALL. WESTERLY/UPSLOPE FLOW WILL HELP ADD LOW-LEVEL LIFT.
THE QPF GENERATED BY ALL THE MODELS AND IN THE SREF PLUMES IS LESS
THAN A TENTH - EVEN IN THOSE UPSLOPE AREAS. SO...WHILE VERY LIGHT
SNOW IS LIKELY IN THE WEST NEW YEARS EVE/NIGHT DUE TO THE
PERSISTENT CONSENSUS AMONG THE MDLS...THE ACCUMS WILL BE ALMOST
NIL. DRYING ON THE NWRLY WINDS AND BEHIND THE STRENGTHENING JET
STREAK WILL DECREASE THE POPS ON TUES...BUT -14C AIR CROSSING THE
LAKES WILL GENERATE SOME LAKE EFFECT SHSN DOWNWIND.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
LATEST MED RANGE GUID BACKS OFF ON THE MAGNITUDE/COLDNESS OF THE
AIR MASS MOVING INTO THE NERN U.S. THIS WEEK. THUS...HAVE BUMPED
UP THE TEMPS SLIGHTLY FOR THE LONG TERM. BUT THE NW FLOW
CONTINUES...AND NOTHING ELSE WAS CHANGED WITH THE OVERNIGHT PKG.
PREV DISC FOLLOWS...
LAKE ENHANCED BANDS SHOULD CONTINUE THROUGH WEDNESDAY
MORNING...AND PERHAPS WEDNESDAY AFTERNOON. A FEW NORTHERN STREAM
FEATURES WILL CROSS THE LOWER GREAT LAKES AROUND MID-WEEK AND MAKE
LAKE EFFECT SHOWERS. AN ARCTIC AIR MASS BEGINS TO MOVE THROUGH
SOUTHERN CANADA AND DECREASING 850MB TEMPERATURES WILL CONTINUE
THROUGH THE LATTER HALF OF THE WEEK. CURRENT RUNS HAVE PA UNDER
M16C TEMPERATURES AT 850MB THURSDAY MORNING. THE GFS AND EC
PROPAGATE ANOTHER TROUGH THROUGH PENNSYLVANIA FRIDAY. THE EC
SPEEDS UP THIS TROUGH AS THE GFS SLOWS THE SYSTEM DOWN. THE
MOVEMENT OF THE LARGE UPPER LEVEL LOW DRIVING THIS SUCCESSIVE
SHORT WAVE TROUGHS VARIES BETWEEN THE MODELS. THE EC MOVES IT
QUICKER THROUGH NOVA SCOTIA AND THEN EXITING TO THE NORTHEAST. THE
GFS SLOWS IT DOWN ON A MORE EASTERLY TRACK. EITHER WAY...EXPECT
HIGH TEMPERATURES THIS WEEK TO BE AT OR BELOW FREEZING...MONDAY
AND TUESDAY BEING THE WARMEST DAYS. HIGHS AFTER THE TROUGH PASSAGE
INTO TUESDAY WILL HAVE HIGHS IN THE UPPER TEENS BY THE END OF THE
UP COMING WEEK. COUPLE THE LOW TEMPS WITH THE GUSTY FLOW...AND
WIND CHILLS COULD BE AN ISSUE DURING THIS TIME FRAME. LOWS THROUGH
THE LATER HALF OF THE WEEK SHOULD BE IN THE LOW TEENS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NWRLY UPSLOPE FLOW WILL KEEP IFR/MVFR CONDS AND SCTD SHSN ACROSS
THE NW MTNS AND LAUREL HIGHLANDS INTO THIS EVENING. VFR TO
OCCASIONALLY MVFR IN -SHSN AT THE CENTRAL MTN TERMINALS /AOO AND
UNV/. FARTHER EAST...CONDS HAVE RETURNED TO VFR...WITH EVEN SOME
BREAKS IN THE OVC.
BLUSTERY NW WINDS WILL GRADUALLY BEGIN TO DIMINISH THIS EVE.
HOWEVER...OCCASIONAL GUSTS OVER 30 MPH REMAIN POSSIBLE UNTIL
THEN.
LINGERING SHSN ACTIVITY SHOULD TAPER OFF OVERNIGHT...ALTHOUGH
SOME LOW CLOUDS MAY LINGER ACROSS THE WEST.
CONDS IMPROVE ON AREA-WIDE MONDAY...AS HIGH PRESSURE BRIEFLY
BUILDS INTO THE REGION.
OUTLOOK...
MON...VFR EAST...BECOMING VFR WEST.
MON NIGHT-TUES...SOME MVFR POSS...WITH -SHSN POSS.
WED-THU...GENERALLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ024-033.
WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR PAZ024>026-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...GRUMM/DANGELO
NEAR TERM...GRUMM/DANGELO
SHORT TERM...GRUMM/DANGELO
LONG TERM...DANGELO/CERU
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1215 PM EST SUN DEC 30 2012
.SYNOPSIS...
A TROUGH IS FORECAST TO PERSIST OVER THE EASTERN UNITED STATES FOR
THE NEXT WEEK. THIS WILL KEEP THE MAIN STORM TRACK SUPPRESSED TO
OUR SOUTH. A SURGE OF ARCTIC AIR AND A WEAK WAVE COULD BRING SNOW
SHOWERS TO WESTERN AREAS NEW YEARS EVE. BEHIND THIS SYSTEM THE
ARCTIC FRONT COULD PUSH INTO PENNSYLVANIA ON NEW YEARS DAY AND
INTO WEDNESDAY. GENERALLY COLD PATTERN WITH NO BIG STORMS FORECAST.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SNOW SHOWERS CONTINUE OVER CENTRAL PENNSYLVANIA. EAST OF THE
HIGHER TERRAIN THEY MAINLY PRODUCE A BRIEF DUSTING OF SNOW. THERE
HAS BEEN A PERSISTENT NW TO SE BAND THAT HAS EXTENDED THROUGH
STATE COLLEGE AT TIMES...BUT RECENTLY THE HIGHER ECHOES HAVE
DRIFTED NORTH. THIS FEATURE HAS PRODUCED LIGHT SNOW SHOWERS.
THERE IS STILL SOME ON GOING SNOW IN THE SW MOUNTAINS AND WILL LET
THE ADVISORY FOR 3-5 INCHES OF SNOW EXPIRE AT 18Z AS SNOW
DIMINISHES DURING THE DAY AND ACCUMULATIONS DIMINISH TOO.
STRONG WINDS AT 850 HPA...OVER 50 KTS AND A FAIRLY GOOD PRESSURE
RISE-FALL COUPLET IN 6 HOUR NAM12 AND RUC13 HAVE FAVORED A WIND
ADVISORY. IN WESTERN PA WINDS OVER 40 KTS SHOULD BE CONFINED TO
ABOUT ABOVE ABOUT 1800 FT. SOME STRONGER WINDS WITH DOWN-SLOPE
EFFECT IN SOUTHERN PA POSSIBLE TOO. GUST ALREADY IN MID-30KT RANGE
IN LOWER SUSQUEHANNA VALLEY. PUT ADVISORY ACROSS ALL OF SOUTHERN
TIER TO INCLUDE YORK-HARRISBURG AND LANCASTER AREAS. SHOULD BE
OVER LATE AFTERNOON WITH INCREASING STABILITY.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY/...
SNOW SUBSIDES IN WEST AND WINDS SLOWLY ABATE SUNDAY NIGHT. THERE
ARE HINTS OF SOME LIGHT SNOW MOVING INTO THE WESTERN AREAS LATE IN
THE AFTERNOON OR EVENING NEW YEARS EVE. AS STATE IN PREVIOUS
SHIFTS DISCUSSION...
PREVIOUS DISCUSSION....WARM ADVECTION TONIGHT WILL TRY TO CLEAR OUT THE
SKIES...BUT MESO MDLS STILL PRODUCE MEAGER QPF IN THE FAR NW.
THUS...SCT/ISOLD SHSN MAY CONTINUE FOR THE FIRST HALF OF THE
NIGHT. CLOUDS WILL BE TOUGH TO CLEAR OVER THE NRN HALF OF THE
AREA...AND HIGH CLOUDS WILL START TO ARRIVE FROM THE WEST BY
MONDAY MORNING. JET STREAM BRIEFLY RIDGES N OF THE AREA TONIGHT
AND MONDAY...BUT AN INCREASE IN SPEED WILL OCCUR MONDAY OVER THE
OHIO VALLEY AND SPREAD ACROSS THE STATE MON NIGHT. THIS WILL
TRANSPORT A LITTLE MOISTURE UP OVER THE SFC/UPPER RIDGE...BUT NOT
MUCH AT ALL. WESTERLY/UPSLOPE FLOW WILL HELP ADD LOW-LEVEL LIFT.
THE QPF GENERATED BY ALL THE MODELS AND IN THE SREF PLUMES IS LESS
THAN A TENTH - EVEN IN THOSE UPSLOPE AREAS. SO...WHILE VERY LIGHT
SNOW IS LIKELY IN THE WEST NEW YEARS EVE/NIGHT DUE TO THE
PERSISTENT CONSENSUS AMONG THE MDLS...THE ACCUMS WILL BE ALMOST
NIL. DRYING ON THE NWRLY WINDS AND BEHIND THE STRENGTHENING JET
STREAK WILL DECREASE THE POPS ON TUES...BUT -14C AIR CROSSING THE
LAKES WILL GENERATE SOME LAKE EFFECT SHSN DOWNWIND.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LATEST MED RANGE GUID BACKS OFF ON THE MAGNITUDE/COLDNESS OF THE
AIR MASS MOVING INTO THE NERN U.S. THIS WEEK. THUS...HAVE BUMPED
UP THE TEMPS SLIGHTLY FOR THE LONG TERM. BUT THE NW FLOW
CONTINUES...AND NOTHING ELSE WAS CHANGED WITH THE OVERNIGHT PKG.
PREV DISC FOLLOWS...
LAKE ENHANCED BANDS SHOULD CONTINUE THROUGH WEDNESDAY
MORNING...AND PERHAPS WEDNESDAY AFTERNOON. A FEW NORTHERN STREAM
FEATURES WILL CROSS THE LOWER GREAT LAKES AROUND MID-WEEK AND MAKE
LAKE EFFECT SHOWERS. AN ARCTIC AIR MASS BEGINS TO MOVE THROUGH
SOUTHERN CANADA AND DECREASING 850MB TEMPERATURES WILL CONTINUE
THROUGH THE LATTER HALF OF THE WEEK. CURRENT RUNS HAVE PA UNDER
M16C TEMPERATURES AT 850MB THURSDAY MORNING. THE GFS AND EC
PROPAGATE ANOTHER TROUGH THROUGH PENNSYLVANIA FRIDAY. THE EC
SPEEDS UP THIS TROUGH AS THE GFS SLOWS THE SYSTEM DOWN. THE
MOVEMENT OF THE LARGE UPPER LEVEL LOW DRIVING THIS SUCCESSIVE
SHORT WAVE TROUGHS VARIES BETWEEN THE MODELS. THE EC MOVES IT
QUICKER THROUGH NOVA SCOTIA AND THEN EXITING TO THE NORTHEAST. THE
GFS SLOWS IT DOWN ON A MORE EASTERLY TRACK. EITHER WAY...EXPECT
HIGH TEMPERATURES THIS WEEK TO BE AT OR BELOW FREEZING...MONDAY
AND TUESDAY BEING THE WARMEST DAYS. HIGHS AFTER THE TROUGH PASSAGE
INTO TUESDAY WILL HAVE HIGHS IN THE UPPER TEENS BY THE END OF THE
UP COMING WEEK. COUPLE THE LOW TEMPS WITH THE GUSTY FLOW...AND
WIND CHILLS COULD BE AN ISSUE DURING THIS TIME FRAME. LOWS THROUGH
THE LATER HALF OF THE WEEK SHOULD BE IN THE LOW TEENS.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
NW UPSLOPE FLOW WILL KEEP IFR/MVFR CIGS AND SCT SNOW SHOWERS ACROSS
THE NW MTNS AND LAUREL HIGHLANDS THROUGH MUCH OF THE DAY. VFR TO
OCCASIONALLY MVFR IN -SNSH ACROSS THE CENTRAL MTN TERMINALS /AOO
AND UNV/. FARTHER EAST...CONDS HAVE RETURNED TO VFR...WITH EVEN
SOME BREAKS IN THE OVC.
WINDS ARE A PROBLEM ACROSS THE REGION...WITH BLUSTERY NW WINDS
OCCASIONALLY GUSTING OVER 30 MPH.
-SHSN ACTIVITY SHOULD TAPER OFF OVER NIGHT...ALTHOUGH CLOUDS MAY
LINGER ACROSS THE WEST.
OUTLOOK...
MON...VFR EAST...BECOMING VFR WEST.
MON NIGHT-TUES...SOME MVFR POSS...WITH LIGHT SNOW DEVELOPING.
WED-THU...GENERALLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ024-033.
WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR PAZ024>026-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...GRUMM/DANGELO
NEAR TERM...GRUMM/DANGELO
SHORT TERM...GRUMM/DANGELO
LONG TERM...DANGELO/CERU
AVIATION...GRUMM/EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1032 AM EST SUN DEC 30 2012
.SYNOPSIS...
NORTHWEST FLOW WILL DOMINATE THE WEATHER PATTERN FOR THE NEXT
WEEK. THIS WILL CREATE A PROLONGED PERIOD OF COLDER THAN NORMAL
TEMPERATURES...BUT ALSO KEEP SIGNIFICANT STORMINESS CONFINED TO
SOUTH OF THE REGION.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SNOW SHOWERS CONTINUE OVER CENTRAL PENNSYLVANIA. EAST OF THE
HIGHER TERRAIN THEY MAINLY PRODUCE A BRIEF DUSTING OF SNOW. THERE
HAS BEEN A PERSISTENT NW TO SE BAND THAT HAS EXTENDED THROUGH
STATE COLLEGE AT TIMES...BUT RECENTLY THE HIGHER ECHOES HAVE
DRIFTED NORTH. THIS FEATURE HAS PRODUCED LIGHT SNOW SHOWERS.
THERE IS STILL SOME ON GOING SNOW IN THE SW MOUNTAINS AND WILL LET
THE ADVISORY FOR 3-5 INCHES OF SNOW EXPIRE AT 18Z AS SNOW
DIMINISHES DURING THE DAY AND ACCUMULATIONS DIMINISH TOO.
STRONG WINDS AT 850 HPA...OVER 50 KTS AND A FAIRLY GOOD PRESSURE
RISE-FALL COUPLET IN 6 HOUR NAM12 AND RUC13 HAVE FAVORED A WIND
ADVISORY. IN WESTERN PA WINDS OVER 40 KTS SHOULD BE CONFINED TO
ABOUT ABOVE ABOUT 1800 FT. SOME STRONGER WINDS WITH DOWN-SLOPE
EFFECT IN SOUTHERN PA POSSIBLE TOO. GUST ALREADY IN MID-30KT RANGE
IN LOWER SUSQUEHANNA VALLEY. PUT ADVISORY ACROSS ALL OF SOUTHERN
TIER TO INCLUDE YORK-HARRISBURG AND LANCASTER AREAS. SHOULD BE
OVER LATE AFTERNOON WITH INCREASING STABILITY.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY/...
SNOW SUBSIDES IN WEST AND WINDS SLOWLY ABATE SUNDAY NIGHT. THERE
ARE HINTS OF SOME LIGHT SNOW MOVING INTO THE WESTERN AREAS LATE IN
THE AFTERNOON OR EVENING NEW YEARS EVE. AS STATE IN PREVIOUS
SHIFTS DISCUSSION...
PREVIOUS DISCUSSION....WARM ADVECTION TONIGHT WILL TRY TO CLEAR OUT THE
SKIES...BUT MESO MDLS STILL PRODUCE MEAGER QPF IN THE FAR NW.
THUS...SCT/ISOLD SHSN MAY CONTINUE FOR THE FIRST HALF OF THE
NIGHT. CLOUDS WILL BE TOUGH TO CLEAR OVER THE NRN HALF OF THE
AREA...AND HIGH CLOUDS WILL START TO ARRIVE FROM THE WEST BY
MONDAY MORNING. JET STREAM BRIEFLY RIDGES N OF THE AREA TONIGHT
AND MONDAY...BUT AN INCREASE IN SPEED WILL OCCUR MONDAY OVER THE
OHIO VALLEY AND SPREAD ACROSS THE STATE MON NIGHT. THIS WILL
TRANSPORT A LITTLE MOISTURE UP OVER THE SFC/UPPER RIDGE...BUT NOT
MUCH AT ALL. WESTERLY/UPSLOPE FLOW WILL HELP ADD LOW-LEVEL LIFT.
THE QPF GENERATED BY ALL THE MODELS AND IN THE SREF PLUMES IS LESS
THAN A TENTH - EVEN IN THOSE UPSLOPE AREAS. SO...WHILE VERY LIGHT
SNOW IS LIKELY IN THE WEST NEW YEARS EVE/NIGHT DUE TO THE
PERSISTENT CONSENSUS AMONG THE MDLS...THE ACCUMS WILL BE ALMOST
NIL. DRYING ON THE NWRLY WINDS AND BEHIND THE STRENGTHENING JET
STREAK WILL DECREASE THE POPS ON TUES...BUT -14C AIR CROSSING THE
LAKES WILL GENERATE SOME LAKE EFFECT SHSN DOWNWIND.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LATEST MED RANGE GUID BACKS OFF ON THE MAGNITUDE/COLDNESS OF THE
AIR MASS MOVING INTO THE NERN U.S. THIS WEEK. THUS...HAVE BUMPED
UP THE TEMPS SLIGHTLY FOR THE LONG TERM. BUT THE NW FLOW
CONTINUES...AND NOTHING ELSE WAS CHANGED WITH THE OVERNIGHT PKG.
PREV DISC FOLLOWS...
LAKE ENHANCED BANDS SHOULD CONTINUE THROUGH WEDNESDAY
MORNING...AND PERHAPS WEDNESDAY AFTERNOON. A FEW NORTHERN STREAM
FEATURES WILL CROSS THE LOWER GREAT LAKES AROUND MID-WEEK AND MAKE
LAKE EFFECT SHOWERS. AN ARCTIC AIR MASS BEGINS TO MOVE THROUGH
SOUTHERN CANADA AND DECREASING 850MB TEMPERATURES WILL CONTINUE
THROUGH THE LATTER HALF OF THE WEEK. CURRENT RUNS HAVE PA UNDER
M16C TEMPERATURES AT 850MB THURSDAY MORNING. THE GFS AND EC
PROPAGATE ANOTHER TROUGH THROUGH PENNSYLVANIA FRIDAY. THE EC
SPEEDS UP THIS TROUGH AS THE GFS SLOWS THE SYSTEM DOWN. THE
MOVEMENT OF THE LARGE UPPER LEVEL LOW DRIVING THIS SUCCESSIVE
SHORT WAVE TROUGHS VARIES BETWEEN THE MODELS. THE EC MOVES IT
QUICKER THROUGH NOVA SCOTIA AND THEN EXITING TO THE NORTHEAST. THE
GFS SLOWS IT DOWN ON A MORE EASTERLY TRACK. EITHER WAY...EXPECT
HIGH TEMPERATURES THIS WEEK TO BE AT OR BELOW FREEZING...MONDAY
AND TUESDAY BEING THE WARMEST DAYS. HIGHS AFTER THE TROUGH PASSAGE
INTO TUESDAY WILL HAVE HIGHS IN THE UPPER TEENS BY THE END OF THE
UP COMING WEEK. COUPLE THE LOW TEMPS WITH THE GUSTY FLOW...AND
WIND CHILLS COULD BE AN ISSUE DURING THIS TIME FRAME. LOWS THROUGH
THE LATER HALF OF THE WEEK SHOULD BE IN THE LOW TEENS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
NW UPSLOPE FLOW WILL KEEP IFR/MVFR CIGS AND SCT SNOW SHOWERS ACROSS
THE NW MTNS AND LAUREL HIGHLANDS THROUGH MUCH OF THE DAY. VFR TO
OCCASIONALLY MVFR IN -SNSH ACROSS THE CENTRAL MTN TERMINALS /AOO
AND UNV/. FARTHER EAST...CONDS HAVE RETURNED TO VFR...WITH EVEN
SOME BREAKS IN THE OVC.
WINDS ARE A PROBLEM ACROSS THE REGION...WITH BLUSTERY NW WINDS
OCCASIONALLY GUSTING OVER 30 MPH.
-SHSN ACTIVITY SHOULD TAPER OFF OVER NIGHT...ALTHOUGH CLOUDS MAY
LINGER ACROSS THE WEST.
OUTLOOK...
MON...VFR EAST...BECOMING VFR WEST.
MON NIGHT-TUES...SOME MVFR POSS...WITH LIGHT SNOW DEVELOPING.
WED-THU...GENERALLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ024-033.
WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR PAZ024>026-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...GRUMM/DANGELO
SHORT TERM...GRUMM/DANGELO
LONG TERM...DANGELO/CERU
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
959 AM EST SUN DEC 30 2012
.SYNOPSIS...
NORTHWEST FLOW WILL DOMINATE THE WEATHER PATTERN FOR THE NEXT
WEEK. THIS WILL CREATE A PROLONGED PERIOD OF COLDER THAN NORMAL
TEMPERATURES...BUT ALSO KEEP SIGNIFICANT STORMINESS CONFINED TO
SOUTH OF THE REGION.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SNOW SHOWERS CONTINUE OVER CENTRAL PENNSYLVANIA. EAST OF THE
HIGHER TERRAIN THEY MAINLY PRODUCE A BRIEF DUSTING OF SNOW. THERE
HAS BEEN A PERSISTENT NW TO SE BAND THAT HAS EXTENDED THROUGH
STATE COLLEGE AT TIMES...BUT RECENTLY THE HIGHER ECHOES HAVE
DRIFTED NORTH. THIS FEATURE HAS PRODUCED LIGHT SNOW SHOWERS.
THERE IS STILL SOME ON GOING SNOW IN THE SW MOUNTAINS AND WILL LET
THE ADVISORY FOR 3-5 INCHES OF SNOW EXPIRE AT 18Z AS SNOW
DIMINISHES DURING THE DAY AND ACCUMULATIONS DIMINISH TOO.
STRONG WINDS AT 850 HPA...OVER 50 KTS AND A FAIRLY GOOD PRESSURE
RISE-FALL COUPLET IN 6 HOUR NAM12 AND RUC13 HAVE FAVORED A WIND
ADVISORY. IN WESTERN PA WINDS OVER 40 KTS SHOULD BE CONFINED TO
ABOUT ABOVE ABOUT 1800 FT. SOME STRONGER WINDS WITH DOWN-SLOPE
EFFECT IN SOUTHERN PA POSSIBLE TOO. GUST ALREADY IN MID-30KT RANGE
IN LOWER SUSQUEHANNA VALLEY. PUT ADVISORY ACROSS ALL OF SOUTHERN
TIER TO INCLUDE YORK-HARRISBURG AND LANCASTER AREAS. SHOULD BE
OVER LATE AFTERNOON WITH INCREASING STABILITY.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY/...
SNOW SUBSIDES IN WEST AND WINDS SLOWLY ABATE SUNDAY NIGHT. THERE
ARE HINTS OF SOME LIGHT SNOW MOVING INTO THE WESTERN AREAS LATE IN
THE AFTERNOON OR EVENING NEW YEARS EVE. AS STATE IN PREVIOUS
SHIFTS DISCUSSION...
PREVIOUS DISCUSSION....WARM ADVECTION TONIGHT WILL TRY TO CLEAR OUT THE
SKIES...BUT MESO MDLS STILL PRODUCE MEAGER QPF IN THE FAR NW.
THUS...SCT/ISOLD SHSN MAY CONTINUE FOR THE FIRST HALF OF THE
NIGHT. CLOUDS WILL BE TOUGH TO CLEAR OVER THE NRN HALF OF THE
AREA...AND HIGH CLOUDS WILL START TO ARRIVE FROM THE WEST BY
MONDAY MORNING. JET STREAM BRIEFLY RIDGES N OF THE AREA TONIGHT
AND MONDAY...BUT AN INCREASE IN SPEED WILL OCCUR MONDAY OVER THE
OHIO VALLEY AND SPREAD ACROSS THE STATE MON NIGHT. THIS WILL
TRANSPORT A LITTLE MOISTURE UP OVER THE SFC/UPPER RIDGE...BUT NOT
MUCH AT ALL. WESTERLY/UPSLOPE FLOW WILL HELP ADD LOW-LEVEL LIFT.
THE QPF GENERATED BY ALL THE MODELS AND IN THE SREF PLUMES IS LESS
THAN A TENTH - EVEN IN THOSE UPSLOPE AREAS. SO...WHILE VERY LIGHT
SNOW IS LIKELY IN THE WEST NEW YEARS EVE/NIGHT DUE TO THE
PERSISTENT CONSENSUS AMONG THE MDLS...THE ACCUMS WILL BE ALMOST
NIL. DRYING ON THE NWRLY WINDS AND BEHIND THE STRENGTHENING JET
STREAK WILL DECREASE THE POPS ON TUES...BUT -14C AIR CROSSING THE
LAKES WILL GENERATE SOME LAKE EFFECT SHSN DOWNWIND.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LATEST MED RANGE GUID BACKS OFF ON THE MAGNITUDE/COLDNESS OF THE
AIR MASS MOVING INTO THE NERN U.S. THIS WEEK. THUS...HAVE BUMPED
UP THE TEMPS SLIGHTLY FOR THE LONG TERM. BUT THE NW FLOW
CONTINUES...AND NOTHING ELSE WAS CHANGED WITH THE OVERNIGHT PKG.
PREV DISC FOLLOWS...
LAKE ENHANCED BANDS SHOULD CONTINUE THROUGH WEDNESDAY
MORNING...AND PERHAPS WEDNESDAY AFTERNOON. A FEW NORTHERN STREAM
FEATURES WILL CROSS THE LOWER GREAT LAKES AROUND MID-WEEK AND MAKE
LAKE EFFECT SHOWERS. AN ARCTIC AIR MASS BEGINS TO MOVE THROUGH
SOUTHERN CANADA AND DECREASING 850MB TEMPERATURES WILL CONTINUE
THROUGH THE LATTER HALF OF THE WEEK. CURRENT RUNS HAVE PA UNDER
M16C TEMPERATURES AT 850MB THURSDAY MORNING. THE GFS AND EC
PROPAGATE ANOTHER TROUGH THROUGH PENNSYLVANIA FRIDAY. THE EC
SPEEDS UP THIS TROUGH AS THE GFS SLOWS THE SYSTEM DOWN. THE
MOVEMENT OF THE LARGE UPPER LEVEL LOW DRIVING THIS SUCCESSIVE
SHORT WAVE TROUGHS VARIES BETWEEN THE MODELS. THE EC MOVES IT
QUICKER THROUGH NOVA SCOTIA AND THEN EXITING TO THE NORTHEAST. THE
GFS SLOWS IT DOWN ON A MORE EASTERLY TRACK. EITHER WAY...EXPECT
HIGH TEMPERATURES THIS WEEK TO BE AT OR BELOW FREEZING...MONDAY
AND TUESDAY BEING THE WARMEST DAYS. HIGHS AFTER THE TROUGH PASSAGE
INTO TUESDAY WILL HAVE HIGHS IN THE UPPER TEENS BY THE END OF THE
UP COMING WEEK. COUPLE THE LOW TEMPS WITH THE GUSTY FLOW...AND
WIND CHILLS COULD BE AN ISSUE DURING THIS TIME FRAME. LOWS THROUGH
THE LATER HALF OF THE WEEK SHOULD BE IN THE LOW TEENS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
NW UPSLOPE FLOW WILL KEEP IFR/MVFR CIGS AND SCT SNOW SHOWERS ACROSS
THE NW MTNS AND LAUREL HIGHLANDS FOR A FEW HOURS PAST SUNRISE.
ELSEWHERE..CONDS HAVE RETURNED TO VFR...WITH EVEN SOME BREAKS IN THE
OVC OVER THE SE. MOST SIG BAND OF SNOW SHOWERS STRETCHES SE FROM
KAOO TO KTHV. THIS SHOULD MAKE FOR SOME REDUCED CIGS AND VSYBS BUT
REMAIN CLEAR OF ANY CENTRAL PA AIRFIELDS.
SNOW SHOULD DIMINISH AS DAY WEARS ON.
WINDS ARE PROBLEM ACROSS THE REGION WITH STRONG GUSTY NW WINDS AND
SIGNIFICANT GUST SPREADS AT TIMES THROUGH 20-21Z.
OUTLOOK...
FRI...MVFR/IFR OVER MOUNTAINS OF THE WEST WITH SNOW
SHOWERS...MVFR/VFR CENTRAL AND EASTERN TERMINALS WITH OCCASIONAL
SNOW SHOWERS/FLURRIES.
FRI NIGHT...IFR/LIFR OVER WESTERN MOUNTAINS IN SNOW SQUALLS...MVFR
TO VFR ELSEWHERE.
SAT...BREEZY. LAKE EFFECT SNOWS CONTINUE IN N AND WEST MTNS WITH
IFR/MVFR CONDITIONS. MVFR IN SNOW SHOWERS CENTRAL. VFR SE.
SUN...MVFR NW. VFR ELSEWHERE.
MON...GENERALLY VFR.
TUES...SOME MVFR POSS...WITH LIGHT RAIN/SNOW DEVELOPING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ024-033.
WIND ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR PAZ024>026-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...GRUMM/DANGELO
SHORT TERM...GRUMM/DANGELO
LONG TERM...DANGELO/CERU
AVIATION...GRUMM/GARTNER
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
555 PM CST MON DEC 31 2012
.DISCUSSION.../ISSUED AT 255 PM CST/
FOCUS TONIGHT WILL BE ON STRATUS IN THE WESTERN CWA AND WEATHER OR
NOT THAT WILL TRANSLATE EAST. THE REASON THIS IS SO IMPORTANT IS IT
WILL LIKELY HAVE A 10 TO 15 DEGREE AFFECT ON TEMPERATURES...WITH
AREAS STAYING OUT OF THE STRATUS FALLING TO AROUND 10 BELOW WHILE
THOSE AREAS UNDER THE STRATUS SHOULD DROP TO ABOUT 5 ABOVE OR SO.
DRY ARCTIC AIR INTRUDING FROM THE NORTHEAST SHOULD HOLD THE STRATUS
AT BAY THROUGH MID EVENING BUT HAVE THE FEELING THAT IT WILL WORK
EASTWARD ACROSS INTERSTATE 29 INTO NORTHWEST IOWA. THE AREA WITH THE
BEST CHANCE TO REMAIN IN THE CLEAR WILL BE ALONG AND EAST OF THE
BUFFALO RIDGE...SO WILL KEEP LOWS AROUND 10 BELOW IN THESE
LOCATIONS. WILL THEN TRANSITION TO LOWS OF ABOUT 5 TO 10 ABOVE ZERO
IN CENTRAL SOUTH DAKOTA WHERE CLOUDS ARE IN PLACE AND A LIGHT SOUTH
TO SOUTHWEST WIND SHOULD DEVELOP LATE TONIGHT. THE INTERSTATE 29
CORRIDOR THE TOUGHEST CALL BECAUSE IF STRATUS COMES IN AROUND SUNSET
LOWS WILL LIKELY BE 10 DEGREES HIGHER THAN FORECAST. ALSO NEED TO
WATCH THE SNOW TO THE SOUTH AS A FEW FLURRIES COULD WORK NORTH
TOWARDS SIOUX CITY AND STORM LAKE THIS EVENING BUT FOR NOW BELIEVE
THAT THE DRY ARCTIC AIR IN THE LOWER LEVELS WILL KEEP THE FLAKES TO
THE SOUTH.
EXPECT THE STRATUS TO LIFT AND PARTLY TO MOSTLY SUNNY SKIES TO
DEVELOP ON TUESDAY AS A WEST TO SOUTHWEST WIND BRINGS IN MILDER
READINGS. RAISED HIGHS A BIT AND KEPT TEMPERATURES WARMER THAN
GUIDANCE BY LATE IN THE DAY AS CONDITIONS SHOULD REMAIN MIXED INTO
THE EVENING. EXPECT HIGHS NEAR 20 IN THE EAST AND NEAR 30 IN THE
WEST. /08
A WEAK AND DISORGANIZED WAVE WILL MOVE ACROSS THE AREA ON WEDNESDAY
WHICH WILL BE FOLLOWED BY ANOTHER BRIEF SHOT OF COLD AIR. THE UPPER
WAVE WAVE WILL BEGIN TO APPROACH ON TUESDAY NIGHT WITH AN INCREASE
IN BOTH CLOUDS AND WESTERLY WINDS. WITH WEST WINDS INCREASING
THROUGH THE NIGHT...EXPECT THAT MOST PLACES WILL REACH LOWS IN THE
EVENING WITH RISING TEMPERATURES OVERNIGHT. SOME LIGHT SNOW MAY MOVE
IN LATE IN THE NIGHT WEST OF THE JAMES RIVER.
THE UPPER WAVE MOVES ACROSS ON WEDNESDAY. THERE IS LITTLE TO NO
FRONTOGENESIS OR EVEN WARM ADVECTION WITH THIS SYSTEM...IT RELIES
ENTIRELY ON THE UPPER LEVEL WAVE. ALL MODELS SHOW THAT THE DYNAMICS
REALLY BEGIN TO WEAKEN AND SPLIT WITH SOME ENERGY DIVING INTO
NEBRASKA AND THE REST STAYING CLOSER TO I94. AS A RESULT...WHILE WE
EXPECT TO SEE FLURRIES WITH THIS SYSTEM BETWEEN WEDNESDAY AND
WEDNESDAY NIGHT...THE PROBABILITY OF MEASURABLE SNOW REMAINS
LOW...50 PERCENT OR LESS. AND FOR LOCATIONS THAT SEE MEASURABLE
SNOWFALL...IT SHOULD BE LESS THAN AN INCH AND LIKELY LESS THAN A
HALF INCH. THE BEST CHANCE FOR MEASURABLE SNOW WILL BE WEDNESDAY
AFTERNOON...ALTHOUGH FLURRIES ARE LIKELY TO CONTINUE INTO WEDNESDAY
NIGHT. HIGHS WEDNESDAY WILL BE IN THE 20S. WITH THE COLD AIR MOVING
IN ON NW WINDS...LOW WEDNESDAY NIGHT WILL BE IN THE SINGLE DIGITS
ABOVE ZERO.
THURSDAY LOOKS TO BE BELOW NORMAL AS COLD AIR MOVES IN EAST OF THE
JAMES RIVER. THIS COLD AIR WILL NOT LAST LONG AND WARMING WILL
ALREADY MOVE INTO AREAS WEST OF THE JAMES BY THURSDAY AFTERNOON.
EVEN WITH WEAK EARLY JANUARY SUN...HIGHS WILL STRUGGLE TO GET ABOVE
10 DEGREES EAST OF THE JAMES...BUT SHOULD APPROACH 20 IN SOUTH
CENTRAL SD. THURSDAY NIGHT COULD BE A REPEAT OF TUESDAY NIGHT WITH A
QUICK DROP FOR 5 TO 10 DEGREES AND THEN RISING TEMPERATURES AS
WESTERLY WINDS PICK UP.
FOR FRIDAY THROUGH MONDAY...IT IS LOOKING LIKE A FAIRLY SIGNIFICANT
WARMING TREND WITH NO PRECIPITATION. THERE IS VERY LITTLE DIFFERENCE
BETWEEN THE ECMWF...GFS AND THE GFS ENSEMBLE. ALL AGREE THAT A LONG
WAVE RIDGE WILL SET UP OVER THE CWA. WHILE A WAVE WILL DROP
SOUTHEAST IN THE NW FLOW ON FRIDAY NIGHT AND SATURDAY...IT WILL
BRING ONLY A BRIEF PERIOD OF COOLER AIR FOLLOWED BY VERY MILD AIR BY
SUNDAY. THE ONLY QUESTION REALLY IS HOW MUCH SNOW COVER INHIBITS
MIXING AND WARMING DURING THE DAY. THE SNOWPACK...WHILE FROM 4 TO
10 INCHES...IS FAIRLY DRY AND WITH A LONG ENOUGH WARM PERIOD COULD
BE SIGNIFICANTLY REDUCED BY MONDAY. FOR NOW STAYED CONSERVATIVE WITH
HIGHS FRIDAY AND SATURDAY IN THE 20S AND 30S. HAVE THE WARMEST DAY
ON SUNDAY WITH HIGHS IN THE 30S AND 40S AND SIMILAR TEMPERATURES
FORECAST FOR MONDAY. IF SNOWCOVER DISAPPEARS FASTER THAN
EXPECTED...HIGHS BY SUNDAY AND MONDAY COULD BE ANOTHER 5 TO 10
DEGREES WARMER./SCHUMACHER
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
CONDITIONS SHOULD REMAIN VFR FOR MANY AREAS EAST OF THE I 29
CORRIDOR FOR TONIGHT AND EARLY TUESDAY. HOWEVER ALONG AND WEST OF I
29...CONDITIONS BECOME MORE PROBLEMATIC. THERE ARE GENERALLY FOUR
LAYERS OF CLOUDS. ONE IS AROUND 8000 FEET AGL EXTENDING THROUGH MUCH
OF EAST CENTRAL AND SOUTHEAST SD. ANOTHER IS NEAR 3000 FEET AGL IN
EAST CENTRAL SD...ARCHING SOUTHWARD TO JUST NORTH OF KFSD. A THIRD
DECK IS CURRENTLY NEAR 2200 FEET AGL IN THE MIDDLE PORTIONS OF THE
JAMES RIVER VALLEY...WHILE THE LAST DECK OF AROUND 1500 FEET IS
EVIDENT IN SOUTH CENTRAL SD. FURTHERMORE...THE IR VIS/FOG CURVE SHOW
THAT KHON AND KMHE ARE ACTUALLY ON THE VERY EDGE OF THE 2200 FOOT
DECK WITH MID LEVEL CLOUDS IN BETWEEN THE TWO SITES. WINDS OFF THE
SURFACE ARE THE KEY...AND MAINLY FOLLOWED THE RUC13 FOR GUIDANCE.
THEREFORE THE KFSD AND KHON TAF SITES SHOULD SEE MVFR CONDITIONS FOR
MUCH OF THE NIGHT AND TUESDAY MORNING...BUT AT TIMES WILL PROBABLY
BE VFR NEAR 8000 FEET DEPENDING ON EXACT MOVEMENT OF THE MVFR DECK.
KSUX MAY BE IN A SWEET SPOT...TOO FAR SOUTH TO BE IMPACTED BY THE
SOUTH DAKOTA STRATUS...AND TOO FAR NORTH TO BE IMPACTED BY THE UPPER
LOW TO THE SOUTH. THAT SAID...WINDS OFF THE SURFACE IN THE BOUNDARY
LAYER SWITCH TO THE SOUTHWEST TUESDAY MORNING...SO AM CONCERNED THAT
SOME STRATUS IN THE CENTRAL PLAINS WILL MOVE INTO KSUX AS TUESDAY
MORNING PROGRESSES. FURTHERMORE...WITH THE AFOREMENTIONED WINDS OFF
THE SURFACE ALSO OF A SOUTHWEST DIRECTION FOR THE KFSD AND KHON TAF
SITES...AM NOT OVERLY CONFIDENT THAT THEY WILL SCATTER OUT IN THE
AFTERNOON ON TUESDAY...AGAIN DUE TO THE ABUNDANT STRATUS IN THE
CENTRAL PLAINS. /MJF
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY
FOR IAZ002-003-014-022.
MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY
FOR MNZ071-072-080-081-089-090.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1048 PM EST MON DEC 31 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO MOVE OFFSHORE TONIGHT...WHILE A
WEAK LOW PRESSURE LOW PRESSURE SYSTEM WILL PASS ALONG THE GULF
COAST OVERNIGHT AND TUESDAY. THIS SYSTEM WILL BRING A MIX OF RAIN
AND WINTRY PRECIPITATION TO THE AREA LATER TONIGHT...BEFORE
PRECIPITATION TRANSITIONS TO RAIN LATE TUESDAY MORNING. THE SYSTEM
WILL PAST EAST OF THE AREA TUESDAY NIGHT...WITH HIGH PRESSURE
BUILDING IN FROM THE WEST ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 800 PM EST MONDAY...
INITIAL BATCH OF PRECIP...MOSTLY ALOFT...HAS FADED ACROSS THE FAR
WEST THIS EVENING AS LATEST SOUNDINGS SHOW QUITE A DRY ENVIRONMENT
BELOW 7H. GIVEN SUCH A STRONG WESTERLY FLOW THROUGH THE DRY LAYER
WOULD EXPECT WILL TAKE QUITE A BIT OF TIME TO SATURATE ESPCLY
GOING EAST OF THE MOUNTAINS PER LATEST GSO RAOB THIS EVENING. NEXT
RIPPLE OF ENERGY JUST WEST OF THE TN VALLEY LOOKS TO BE THE MAIN
THREAT TO PRODUCE LIGHT PRECIP LATER TONIGHT AS IT FEEDS EASTWARD
AND LIKELY AFFECTS SPOTS OVER SW VA INTO SE WVA PER LATEST
NAM/RAP. SOME OF THIS COULD SLIP OUT TO THE BLUE RIDGE AROUND
DAYBREAK WHEN FORECAST SOUNDINGS FINALLY SHOW THE LOWEST LEVELS
MOISTENING. THUS HAVE TRIMMED BACK POPS TO INIT THIS EVENING WITH
MOSTLY CHANCE POPS WESTERN THIRD AND MAINLY DRY OUT EAST UNTIL
AROUND 12Z/7AM TUESDAY. PTYPE REMAINS AN ISSUE PENDING DEGREE OF
COOLING WITH ONLY LIGHT PRECIP AND ISOTHERMAL LAYERS OFF NAM
SOUNDINGS TOWARD DAWN. FOR NOW BASICALLY KEPT IT MOSTLY RAIN
OUTSIDE OF THE COLDER NW WHERE WENT WITH A SNOW/SLEET MIXTURE AND
MORE SLEET AT THE ONSET. THINK ANY FREEZING RAIN WOULD BE CONFINED
MOSTLY TO NW VALLEYS AND LIKELY NOT UNTIL EARLY TUESDAY WHEN
THINGS BECOME SATURATED ALLOWING LESS FROZEN NATURE. BUMPED UP
TEMPS SOME ESPCLY BLUE RIDGE EAST WHERE CLOUDS AND LACK OF RAIN
ALONG WITH MIXING SHOULD LIMIT COOLING. MAY SEE SOME LOCATIONS NOT
DROP BELOW 40 SE OTRW TRENDING FROM 28-35 WEST TO 35-40 EAST.
BY MID MORNING TUESDAY...LOW LEVEL TEMPERATURES ARE EXPECTED TO
REBOUND ABOVE FREEZING...RESULTING IN MAINLY RAIN ACROSS THE
AREA...WHILE PORTIONS OF SOUTHEAST WEST VIRGINIA AND THE ALLEGHANY
HIGHLANDS WILL LIKELY KEEP SNOW THROUGH THE AFTERNOON. AS THE LOW
PRESSURE SYSTEM CONTINUES EAST THROUGH THE DAY...EXPECT WINDS
ACROSS THE AREA TO BECOME MORE NORTHWESTERLY DURING THE EVENING...
ALLOWING COLDER AIR TO BUILD IN WHICH WILL CAUSE RAIN TO
TRANSITION TO SNOW SHOWER ACTIVITY FROM WEST TO EAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 220 PM MONDAY...
POSITION OF UPPER JET AND SFC FEATURES ARE GOING TO IMPACT OUR
WEATHER TUES NIGHT AS MAIN FOCUS OF PRECIP SHIFTS SOUTH OF US. STILL
ENOUGH AMPLE MOISTURE EARLY TO KEEP HIGHER POPS OVER THE SOUTH AND
WEST...WITH RAIN TRANSITIONING OVER TO SNOW AS COLDER AIR STARTS TO
WORK BACK IN FROM THE NORTHWEST. MODELS ARE IN ENOUGH AGREEMENT AND
ARE KEEPING THE THERMAL PROFILE AS MORE OF A RAIN/SNOW
LAYOUT...GIVEN LACK OF DEEP SW FLOW AT 8H WITH WEAK WARM NOSE. THERE
APPEARS TO BE AT TIMES A SLIGHT RISE ABOVE FREEZING EARLY THAT
CANNOT RULE OUT SLEET THOUGH ITS MARGINAL SO LEFT THE PTYPE TUE
EVENING AS RAIN/SNOW.
LATE TUESDAY NIGHT...THE SYSTEM SHIFTS SOUTHEAST AND WILL SEE PRECIP
START TO WANE. MOISTURE BECOMES SHALLOW OVER THE MTNS SUCH THAT
FREEZING DRIZZLE WILL FALL IN THE HIGHER RIDGES.
HIGH PRESSURE STARTS TO WORK INTO THE CENTRAL APPALACHIANS WEDNESDAY
BUT THE SFC FRONT STAYS LOCKED IN OVER THE SOUTHEAST. MAY SEE THE
SOUTHERN HALF OF THE CWA STAY CLOUDY WEDNESDAY WITH SW FLOW
ALOFT....BUT WILL BE CLOSE. ALLOWED FOR MORE CLOUDS THOUGH SHOULD BE
SOME SUNSHINE AT TIMES ESPECIALLY NORTH OF A LINE FROM I-81 IN THE
SOUTHWEST TO LYNCHBURG.
APPEARS MODELS START TO EDGE SOME MOISTURE BACK OUR WAY WED NIGHT-
THU. MARGINAL AT BEST AND WILL KEEP POPS SMALL OVER THE SRN CWA
MAINLY SOUTH OF VA/NC BORDER. IF PRECIP GETS IN EARLY ENOUGH COULD
SEE A FEW SNOW FLAKES AND/OR SLEET PELLETS ACROSS SOUTHSIDE VA/NRN
NC. STILL NOT EXPECTING MUCH.
TEMPS THIS PERIOD STAY COOL GIVEN MORE CLOUDS. HIGHS WED-THU RANGE
FROM THE MID TO UPPER 30S MTNS TO LOWER TO MID 40S EAST.
LOWS ARE GOING TO BE IMPACTED BY CLOUDS AS WELL WITH 20S WEST TO
AROUND 30 TO LOWER 30S SOUTHEAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EST MONDAY...
LOW PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO MOVE EAST INTO
THE ATLANTIC OCEAN THURSDAY NIGHT INTO FRIDAY MORNING. WILL ALLOW
FOR A SLIGHT CHANCE OF RAIN THURSDAY EVENING IN OUR SOUTHEAST WITH
ECMWF SHOWING THE NORTHERN EXTENT OF THE ASSOCIATED PRECIPITATION
BRUSHING THE SOUTHEAST CORNER OF THE CWA. MODEL DIFFERENCES REMAIN
WITH THE TIMING AND STRENGTH OF THE SHORTWAVE WHICH PIVOTS OUT OF
THE OHIO VALLEY AROUND THE UPPER TROUGH THURSDAY NIGHT. BECAUSE OF
THIS UNCERTAINTY...KEPT SOME LIGHT POPS IN THE WESTERN UPSLOPE AREAS
THURSDAY NIGHT INTO FRIDAY. HIGH PRESSURE WILL BUILD EAST OUT OF THE
CENTRAL U.S. ON FRIDAY. THE 1030 MB SURFACE HIGH WILL REMAIN ACROSS
THE REGION DURING THE WEEKEND. WITH THE HIGH CENTER SETTLING SOUTH
AND A SOUTHWEST FLOW WILL CONTINUE TO MODERATE TEMPERATURES EARLY
NEXT WEEK. ANOTHER STORM MAY SPREAD MOISTURE INTO OUR REGION OUT OF
THE CENTRAL PLAINS AROUND THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
AS OF 1035 PM EST MONDAY...
OVERALL MID DECK CANOPY CONTINUES ACROSS THE REGION TONIGHT WITH
DRY AIR LIMITING BASES TO 8 KFT AND ABOVE. RADAR IS ALSO
INDICATING LIGHT RETURNS MAKING THEIR WAY ACROSS THE FAR SW
MOUNTAINS INTO THE AREA...BUT WITH THE LOW LEVELS STILL VERY
DRY...DO NOT SEE MORE THAN LIGHT SPRINKLES OR A FEW SLEET PELLETS
MAKING IT TO THE SURFACE UNTIL THE EARLY MORNING HOURS OF TUESDAY
AS THE NEXT WAVE APPROACHES.
MODELS CONTINUE TO SLOW DOWN ANY EASTWARD PROGRESSION OF PRECIP
OVERNIGHT...LIKELY DUE TO SO MUCH DRY AIR AND ONLY LIGHT PRECIP
GIVEN A LACK OF A WELL DEFINED SURFACE SYSTEM. GUIDANCE ALSO
REMAINS A BIT WARMER PER LESS EVAPORATIVE COOLING PROVIDED BY
ONLY VERY LIGHT PRECIP WITH EVEN THE LATEST RAP AND LOCAL WRF
SOLUTIONS QUITE DRY UNTIL SHORTLY BEFORE DAYBREAK.
HOWEVER...EARLIER MODEL INIT REMAINS ALL OVER THE PLACE UNDER
SUCH A STRUNG OUT AREA OF DEEP MOISTURE ALONG THE SRN JET AND
LIKELY HAVING A HARD TIME IN WHERE TO FOCUS PRECIP ATTM. THUS HAVE
KEPT IN LIGHT MIXED PRECIP FOR MANY OF THE WESTERN SITES WITH
PERHAPS A PERIOD OF VERY LIGHT FREEZING RAIN POSSIBLE IN THE
VALLEYS AT KLWB/KBCB TOWARD DAWN BUT CONFIDENCE LOW. OTRW
INCLUDING A BIT MORE IN THE WAY OF PL MENTION AT LEAST AT THE
ONSET OVERNIGHT ACROSS THE WEST WHILE LEAVING THINGS MAINLY VFR
UNTIL VERY LATE TONIGHT WITH ONLY SPOTTY -RA OUT EAST.
PRECIPITATION WILL BECOME WIDESPREAD TUESDAY MORNING WITH A MUCH
BETTER PROBABILITY OF MVFR OR EVEN IFR CONDITIONS...AND LOW TO
MEDIUM CONFIDENCE THAT SITES FROM KBCB WESTWARD WILL SEE MIXED
PRECIPITATION CHANGE TO RAIN BY LATE MORNING AS TEMPERATURES WARM.
HOWEVER KLWB MAY GET STUCK AROUND FREEZING INTO THE AFTERNOON SO
MAY BE TOUGH TO DISLODGE THE MIXED BAG THERE UNTIL PRECIP TAPERS
OFF IN THE AFTERNOON. AS A SURFACE LOW PRESSURE SYSTEM PASSES
THROUGH THE CAROLINAS TUESDAY AND TUESDAY NIGHT...COLDER AIR WILL
MOVE INTO THE AREA. ON TUESDAY EVENING PRECIPITATION WILL CHANGE
TO SNOW SHOWERS...WHICH WILL CONTINUE IN SOUTHEAST WEST
VIRGINIA...INCLUDING KLWB AND KBLF INTO EARLY WEDNESDAY MORNING.
COULD EVEN BE SOME SPOTTY LIGHT FREEZING RAIN OR PERHAPS SOME
LIGHT SNOW FROM KBCB/KROA TO KLYH TUE NIGHT AS THE PRECIP ENDS.
OTRW APPEARS IFR TO OCNL MVFR CIGS WILL PERSIST ACROSS MOST OF
THE AREA TUESDAY NIGHT OR EARLY WEDNESDAY UNDER SLOWLY IMPROVING
VSBYS AS PRECIPS ENDS OVERNIGHT.
VFR WEATHER IS EXPECTED WEDNESDAY AFTERNOON INTO SATURDAY FOR
MOST OF THE REGION. A LOW PRESSURE SYSTEM PASSING WELL TO THE
SOUTH MAY BRING SUB-VFR CONDITIONS TO DAN ON THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...JH/NF
SHORT TERM...WP
LONG TERM...KK
AVIATION...AMS/JH/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
834 PM EST MON DEC 31 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO MOVE OFFSHORE TONIGHT...WHILE A
WEAK LOW PRESSURE LOW PRESSURE SYSTEM WILL PASS ALONG THE GULF
COAST OVERNIGHT AND TUESDAY. THIS SYSTEM WILL BRING A MIX OF RAIN
AND WINTRY PRECIPITATION TO THE AREA LATER TONIGHT...BEFORE
PRECIPITATION TRANSITIONS TO RAIN LATE TUESDAY MORNING. THE SYSTEM
WILL PAST EAST OF THE AREA TUESDAY NIGHT...WITH HIGH PRESSURE
BUILDING IN FROM THE WEST ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 800 PM EST MONDAY...
INITIAL BATCH OF PRECIP...MOSTLY ALOFT...HAS FADED ACROSS THE FAR
WEST THIS EVENING AS LATEST SOUNDINGS SHOW QUITE A DRY ENVIRONMENT
BELOW 7H. GIVEN SUCH A STRONG WESTERLY FLOW THROUGH THE DRY LAYER
WOULD EXPECT WILL TAKE QUITE A BIT OF TIME TO SATURATE ESPCLY
GOING EAST OF THE MOUNTAINS PER LATEST GSO RAOB THIS EVENING. NEXT
RIPPLE OF ENERGY JUST WEST OF THE TN VALLEY LOOKS TO BE THE MAIN
THREAT TO PRODUCE LIGHT PRECIP LATER TONIGHT AS IT FEEDS EASTWARD
AND LIKELY AFFECTS SPOTS OVER SW VA INTO SE WVA PER LATEST
NAM/RAP. SOME OF THIS COULD SLIP OUT TO THE BLUE RIDGE AROUND
DAYBREAK WHEN FORECAST SOUNDINGS FINALLY SHOW THE LOWEST LEVELS
MOISTENING. THUS HAVE TRIMMED BACK POPS TO INIT THIS EVENING WITH
MOSTLY CHANCE POPS WESTERN THIRD AND MAINLY DRY OUT EAST UNTIL
AROUND 12Z/7AM TUESDAY. PTYPE REMAINS AN ISSUE PENDING DEGREE OF
COOLING WITH ONLY LIGHT PRECIP AND ISOTHERMAL LAYERS OFF NAM
SOUNDINGS TOWARD DAWN. FOR NOW BASICALLY KEPT IT MOSTLY RAIN
OUTSIDE OF THE COLDER NW WHERE WENT WITH A SNOW/SLEET MIXTURE AND
MORE SLEET AT THE ONSET. THINK ANY FREEZING RAIN WOULD BE CONFINED
MOSTLY TO NW VALLEYS AND LIKELY NOT UNTIL EARLY TUESDAY WHEN
THINGS BECOME SATURATED ALLOWING LESS FROZEN NATURE. BUMPED UP
TEMPS SOME ESPCLY BLUE RIDGE EAST WHERE CLOUDS AND LACK OF RAIN
ALONG WITH MIXING SHOULD LIMIT COOLING. MAY SEE SOME LOCATIONS NOT
DROP BELOW 40 SE OTRW TRENDING FROM 28-35 WEST TO 35-40 EAST.
BY MID MORNING TUESDAY...LOW LEVEL TEMPERATURES ARE EXPECTED TO
REBOUND ABOVE FREEZING...RESULTING IN MAINLY RAIN ACROSS THE
AREA...WHILE PORTIONS OF SOUTHEAST WEST VIRGINIA AND THE ALLEGHANY
HIGHLANDS WILL LIKELY KEEP SNOW THROUGH THE AFTERNOON. AS THE LOW
PRESSURE SYSTEM CONTINUES EAST THROUGH THE DAY...EXPECT WINDS
ACROSS THE AREA TO BECOME MORE NORTHWESTERLY DURING THE EVENING...
ALLOWING COLDER AIR TO BUILD IN WHICH WILL CAUSE RAIN TO
TRANSITION TO SNOW SHOWER ACTIVITY FROM WEST TO EAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 220 PM MONDAY...
POSITION OF UPPER JET AND SFC FEATURES ARE GOING TO IMPACT OUR
WEATHER TUES NIGHT AS MAIN FOCUS OF PRECIP SHIFTS SOUTH OF US. STILL
ENOUGH AMPLE MOISTURE EARLY TO KEEP HIGHER POPS OVER THE SOUTH AND
WEST...WITH RAIN TRANSITIONING OVER TO SNOW AS COLDER AIR STARTS TO
WORK BACK IN FROM THE NORTHWEST. MODELS ARE IN ENOUGH AGREEMENT AND
ARE KEEPING THE THERMAL PROFILE AS MORE OF A RAIN/SNOW
LAYOUT...GIVEN LACK OF DEEP SW FLOW AT 8H WITH WEAK WARM NOSE. THERE
APPEARS TO BE AT TIMES A SLIGHT RISE ABOVE FREEZING EARLY THAT
CANNOT RULE OUT SLEET THOUGH ITS MARGINAL SO LEFT THE PTYPE TUE
EVENING AS RAIN/SNOW.
LATE TUESDAY NIGHT...THE SYSTEM SHIFTS SOUTHEAST AND WILL SEE PRECIP
START TO WANE. MOISTURE BECOMES SHALLOW OVER THE MTNS SUCH THAT
FREEZING DRIZZLE WILL FALL IN THE HIGHER RIDGES.
HIGH PRESSURE STARTS TO WORK INTO THE CENTRAL APPALACHIANS WEDNESDAY
BUT THE SFC FRONT STAYS LOCKED IN OVER THE SOUTHEAST. MAY SEE THE
SOUTHERN HALF OF THE CWA STAY CLOUDY WEDNESDAY WITH SW FLOW
ALOFT....BUT WILL BE CLOSE. ALLOWED FOR MORE CLOUDS THOUGH SHOULD BE
SOME SUNSHINE AT TIMES ESPECIALLY NORTH OF A LINE FROM I-81 IN THE
SOUTHWEST TO LYNCHBURG.
APPEARS MODELS START TO EDGE SOME MOISTURE BACK OUR WAY WED NIGHT-
THU. MARGINAL AT BEST AND WILL KEEP POPS SMALL OVER THE SRN CWA
MAINLY SOUTH OF VA/NC BORDER. IF PRECIP GETS IN EARLY ENOUGH COULD
SEE A FEW SNOW FLAKES AND/OR SLEET PELLETS ACROSS SOUTHSIDE VA/NRN
NC. STILL NOT EXPECTING MUCH.
TEMPS THIS PERIOD STAY COOL GIVEN MORE CLOUDS. HIGHS WED-THU RANGE
FROM THE MID TO UPPER 30S MTNS TO LOWER TO MID 40S EAST.
LOWS ARE GOING TO BE IMPACTED BY CLOUDS AS WELL WITH 20S WEST TO
AROUND 30 TO LOWER 30S SOUTHEAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EST MONDAY...
LOW PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO MOVE EAST INTO
THE ATLANTIC OCEAN THURSDAY NIGHT INTO FRIDAY MORNING. WILL ALLOW
FOR A SLIGHT CHANCE OF RAIN THURSDAY EVENING IN OUR SOUTHEAST WITH
ECMWF SHOWING THE NORTHERN EXTENT OF THE ASSOCIATED PRECIPITATION
BRUSHING THE SOUTHEAST CORNER OF THE CWA. MODEL DIFFERENCES REMAIN
WITH THE TIMING AND STRENGTH OF THE SHORTWAVE WHICH PIVOTS OUT OF
THE OHIO VALLEY AROUND THE UPPER TROUGH THURSDAY NIGHT. BECAUSE OF
THIS UNCERTAINTY...KEPT SOME LIGHT POPS IN THE WESTERN UPSLOPE AREAS
THURSDAY NIGHT INTO FRIDAY. HIGH PRESSURE WILL BUILD EAST OUT OF THE
CENTRAL U.S. ON FRIDAY. THE 1030 MB SURFACE HIGH WILL REMAIN ACROSS
THE REGION DURING THE WEEKEND. WITH THE HIGH CENTER SETTLING SOUTH
AND A SOUTHWEST FLOW WILL CONTINUE TO MODERATE TEMPERATURES EARLY
NEXT WEEK. ANOTHER STORM MAY SPREAD MOISTURE INTO OUR REGION OUT OF
THE CENTRAL PLAINS AROUND THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
AS OF 540 PM EST MONDAY...
EXPANSIVE MID DECK CANOPY CONTINUES TO SLOWLY LOWER ACROSS THE
REGION FROM WEST TO EAST ATTM...ALTHOUGH BASES STILL GENERALLY 8 KFT
AND ABOVE. RADAR IS ALSO INDICATING LIGHT RETURNS MAKING THEIR WAY
ACROSS THE FAR SW MOUNTAINS INTO THE AREA...BUT WITH THE LOW
LEVELS STILL VERY DRY...DO NOT SEE MORE THAN LIGHT SPRINKLES OR A
FEW SLEET PELLETS MAKING IT TO THE SURFACE OVER THE NEXT FEW
HOURS.
MODELS CONTINUE TO SLOW DOWN ANY EASTWARD PROGRESSION OF PRECIP
OVERNIGHT...LIKELY DUE TO SO MUCH DRY AIR AND ONLY LIGHT PRECIP
GIVEN A LACK OF A WELL DEFINED SURFACE SYSTEM. GUIDANCE ALSO
REMAINS A BIT WARMER PER LESS EVAPORATIVE COOLING PROVIDED BY
ONLY VERY LIGHT PRECIP WITH EVEN THE LATEST RAP AND LOCAL WRF
SOLUTIONS QUITE DRY UNTIL AROUND DAYBREAK. HOWEVER...MODEL INIT
REMAINS ALL OVER THE PLACE UNDER SUCH A STRUNG OUT AREA OF DEEP
MOISTURE ALONG THE SRN JET AND LIKELY HAVING A HARD TIME IN WHERE
TO FOCUS PRECIP ATTM. THUS HAVE KEPT IN LIGHT MIXED PRECIP FOR
MANY OF THE WESTERN SITES WITH PERHAPS A PERIOD OF VERY LIGHT
FREEZING RAIN POSSIBLE IN THE VALLEYS AT KLWB/KBCB TOWARD DAWN BUT
CONFIDENCE LOW. OTRW INCLUDING A BIT MORE IN THE WAY OF PL MENTION
AT LEAST AT THE ONSET OVERNIGHT ACROSS THE WEST WHILE LEAVING
THINGS MAINLY VFR OVERNIGHT WITH ONLY SPOTTY -RA OUT EAST.
PRECIPITATION WILL BECOME WIDESPREAD TUESDAY MORNING WITH A MUCH
BETTER PROBABILITY OF MVFR OR EVEN IFR CONDITIONS...AND LOW TO
MEDIUM CONFIDENCE THAT SITES FROM KBCB WESTWARD WILL SEE MIXED
PRECIPITATION CHANGE TO RAIN BY LATE MORNING AS TEMPERATURES WARM.
HOWEVER KLWB MAY GET STUCK AROUND FREEZING INTO THE AFTERNOON SO
MAY BE TOUGH TO DISLODGE THE MIXED BAG THERE UNTIL PRECIP TAPERS
OFF IN THE AFTERNOON. AS A SURFACE LOW PRESSURE SYSTEM PASSES
THROUGH THE CAROLINAS TUESDAY AND TUESDAY NIGHT...COLDER AIR WILL
MOVE INTO THE AREA. ON TUESDAY EVENING PRECIPITATION WILL CHANGE
TO SNOW SHOWERS...WHICH WILL CONTINUE IN SOUTHEAST WEST
VIRGINIA...INCLUDING KLWB AND KBLF INTO EARLY WEDNESDAY MORNING.
VFR WEATHER IS EXPECTED WEDNESDAY AFTERNOON INTO SATURDAY FOR
MOST OF THE REGION. A LOW PRESSURE SYSTEM PASSING WELL TO THE
SOUTH MAY BRING SUB-VFR CONDITIONS TO DAN ON THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...JH/NF
SHORT TERM...WP
LONG TERM...KK
AVIATION...AMS/JH/NF
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
902 PM CST MON DEC 31 2012
.UPDATE...
LOW LEVEL COLD ADVECTION CONTINUES AND SKIES HAVE CLEARED SOONER
THAN EXPECTED THIS EVENING. SOME HIGH CLOUDS MAY STILL STREAM
ACROSS THE SOUTH OVERNIGHT...BUT IT IS LOOKING PRETTY THIN UP
STREAM AND DON/T EXPECT IT TO HAVE A MAJOR BLANKETING INFLUENCE ON
TEMPS. ALTHOUGH THERE CONTINUES TO BE A DECENT PRESSURE
GRADIENT...THE CLEAR SKIES HAVE ALLOWED WINDS TO DECOUPLE IN THE
USUAL FAVORED LOW SPOTS. THUS...TEMPS ARE SHOWING WIDE VARIABILITY
OUT THERE...TANKING HARD IN SOME SPOTS...WHILE REMAINING ELEVATED
IN THE HIGHER TERRAIN.
CURRENT TEMP FORECAST STILL LOOKS PRETTY GOOD AND WILL ONLY NEED
TO MAKE SOME MINOR ADJUSTMENTS.
NO OTHER CHANGES NEEDED.
&&
.AVIATION/06Z TAFS/...
HIGH PRESSURE WILL BRING VFR CONDITIONS THROUGH THE TAF PERIOD.
WINDS WILL REMAIN NORTHWEST LESS THAN 10 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 332 PM CST MON DEC 31 2012/
VERY SHORT TERM...TONIGHT AND NEW YEARS DAY...FORECAST CONFIDENCE MEDIUM.
THE GREATEST UNCERTAINTY FOR TONIGHT IS SKY COVER...WHICH WILL
IMPACT THE LOW TEMPERATURES.
COLD AIR ADVECTION WITH CYCLONIC FLOW ALOFT LED TO STRATUS OVER
SOUTHERN WISCONSIN TODAY. THE STRATUS IS DISSIPATING FROM WEST TO
EAST THIS AFTERNOON...AND ALREADY SCATTERED OUT IN MADISON.
MEANWHILE...THE CIRRUS SHIELD OVER SOUTHERN WI SEEMS TO BE TAKING A
LITTLE LONGER TO MOVE OUT OF THE AREA...ALTHOUGH IT APPEARS THIN ON
THE VISIBLE SATELLITE IMAGERY.
925MB TEMPS WILL DROP DOWN TO -12 TO -14C OVERNIGHT. THE PRESSURE
GRADIENT WILL WEAKEN AS HIGH PRESSURE SHIFTS INTO WESTERN WISCONSIN
TONIGHT. SO TEMPS WILL BE SLOWER TO FALL IN THE EVENING...BUT WILL
LIKELY PLUMMET AFTER MIDNIGHT...ESPECIALLY NORTHWEST OF MADISON TO
FOND DU LAC SINCE THEY WILL HAVE THE LONGEST TIME TO RADIATE OUT.
WHILE THE STRATUS WILL LIKELY CLEAR IN THE SOUTHEAST FORECAST AREA
BEFORE MIDNIGHT...IT MAY TAKE LONGER FOR THE CIRRUS TO CLEAR...THUS
KEEPING THE TEMPS HIGHER THROUGH THE NIGHT. TRIED TO STICK CLOSE TO
MOS GUIDANCE IN THIS AREA.
925MB TEMPS WILL HOLD STEADY ON TUESDAY. DESPITE THE EXPECTED
SUNSHINE...MAX TEMPS SHOULD BARELY RISE OUT OF THE SINGLE DIGITS BY
THE AFTERNOON WITH THE EXCEPTION OF NEAR THE LAKESHORE.
SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
THERMAL TROUGH MOVES OFF TO THE EAST WITH INCREASING CLOUDS AND WARM
AIR ADVECTION ON DEVELOPING SOUTHERLY WINDS AS SURFACE RIDGE SLIDES
SOUTHEAST LEADING TO OVERNIGHT LOWS AROUND/JUST AFTER MIDNIGHT...
THEN STEADY OR SLOWLY WARMING TEMPERATURES. RISE CONTINUES INTO
WEDNESDAY AHEAD ON SOUTH WINDS AHEAD OF SHORT WAVE TROUGH AND
ASSOCIATED SURFACE LOW. BEST LOWER LAYER Q-VECTOR CONVERGENCE
CROSSES REGION WEDNESDAY AFTERNOON...BUT MOISTURE LACKING EXCEPT IN
THE FAR NW...SO WILL LIMIT SLIGHT CHANCE POPS TO THERE.
WEDNESDAY NIGHT...FORECAST CONFIDENCE MEDIUM.
HAVE UPPED POPS TO CHANCE IN THE WEST AS MODELS ARE IN AGREEMENT
THAT MOISTURE WILL BE DEEP ENOUGH TO REACH THE DENDRITE GROWTH ZONE
FOR A FEW HOURS...WITH ENOUGH OMEGA FOR A POTENTIAL TO SQUEEZE OUT A
HUNDREDTH OF AN INCH OF QPF AND A FEW TENTHS OF AN INCH OF VERY
LIGHT SNOW. THIS IS STILL A HIGH PROBABILITY OF OCCURRENCE AND LOW
PROBABILITY OF MEASURING SITUATION. TEMPERATURES WILL ONLY COOL
SLOWLY THROUGH THE EVENING AND INTO THE OVERNIGHT...THEN DIP TOWARDS
DAYBREAK WITH CLOUDS HANGING IN AND COLD AIR ADVECTION NOT KICKING IN
UNTIL AFTER 06Z TO 09Z.
THURSDAY...FORECAST CONFIDENCE MEDIUM
COLD ADVECTION DURING THE DAY WILL PREVENT MUCH OF A TEMPERATURE
RISE...HIGHS IN THE LOW TO MID 20S...AS THERMAL TROUGH MOVES
ACROSS REGION DURING THE DAY. CLOUDY SKIES EARLY AND PARTLY SUNNY
SKIES AT BEST IN THE AFTERNOON AS SURFACE RIDGE BUILDS IN LATE IN
THE DAY.
LONG TERM...HURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE LOW
TO MEDIUM.
MODERATING TREND BEGINS WITH MORE WESTERLY UPPER FLOW AS SHORT WAVE
BREAKS DOWN WESTERN RIDGE AND BROAD SURFACE HIGH SETS UP OVER THE
SOUTHERN PLAINS. MODELS DIFFER WITH PCPN CHANCES WITH THIS SHORT
WAVE AS IT MOVES ACROSS THE UPPER MIDWEST SATURDAY/SUNDAY. BLENDED
SOLUTIONS DID NOT CONVERGE WITH A HIGH ENOUGH POP IN ANY ONE PERIOD
TO PRODUCE PRECIPITATION...THOUGH GFS/ECMWF/GEMNH ALL DO PRODUCE
LIGHT QPF. WILL LEAVE DRY FOR NOW...BUT WOULD NOT BE SURPRISED TO
SEE POPS IN LATER FORECASTS. WEST SOUTHWEST FLOW BEHIND THE SHORT
WAVE LEADS TO DOWNSLOPE WARMING OVER THE NORTHERN PLAINS AND RAISES
THICKNESSES TO SUPPORT UPPER 20S TO LOWER 30S SUNDAY...AND LOW TO
MID 30S MONDAY.
AVIATION/00Z TAFS/...
COLD AIR ADVECTION WITH CYCLONIC FLOW ALOFT LED TO STRATUS OVER
SOUTHERN WISCONSIN TODAY. THE AREA OF LOW CLOUDS CANNOT BE SEEN
BENEATH THE DECK OF THE CIRRUS SHIELD IN VISIBLE SATELLITE
IMAGERY...SO RELYING ON SURFACE OBSERVATIONS. THE NORTHWEST EDGE OF
THE STRATUS DECK HAS BEEN GRADUALLY ERODING FROM THE
NORTHWEST...ALREADY SCATTERING OUT AT KMSN. IT HAS NOT SPREAD INTO
KENW YET...BUT ANTICIPATING THAT IT DOES FOR A FEW HOURS THIS
EVENING.
THE LATEST RAP SOUNDINGS IN BUFKIT PICK UP ON THE STRATUS TODAY AND
NOW CLEAR THEM OUT AROUND 04Z. THE CIRRUS MAY BE A LITTLE SLOWER TO
CLEAR.
EXPECTING CLEAR SKIES/VFR CONDITIONS ON TUESDAY WITH LIGHTER WINDS
AS HIGH PRESSURE BUILDS OVER THE AREA.
MARINE...WINDS WILL CONTINUE TO DIMINISH OVERNIGHT AND TUESDAY AS
HIGH PRESSURE BUILDS INTO THE REGION. WITH COLDER AIR SETTLING
IN...WILL NEED TO WATCH FOR FREEZING SPRAY THREAT REST OF THE WEEK.
WINDS WILL INCREASE OUT OF THE SOUTHWEST ON WEDNESDAY AS LOW
PRESSURE MOVES ACROSS LAKE SUPERIOR.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/TUESDAY AND AVIATION/MARINE...MRC
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
916 PM MST MON DEC 31 2012
.UPDATE...
ISSUED AT 904 PM MST MON DEC 31 2012
SNOWFALL HAS DECREASED OVER THE SAN JUAN MOUNTAINS AND PORTIONS OF
SOUTHWEST COLORADO...AND WILL CONTINUE TO DO SO. THE WINTER
WEATHER ADVISORY WAS ALLOWED TO EXPIRE. ONLY LOCALLY LIGHT
ADDITIONAL ACCUMULATIONS ARE EXPECTED OVERNIGHT...MAINLY ON NORTH
AND NORTHWEST FACING SLOPES OF THE SAN JUAN MOUNTAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 300 PM MST MON DEC 31 2012
IMPROVING CONDITIONS AS THE ACTIVE SHORT WAVE MOVES DOWNSTREAM...EXCEPT
FOR SOME ENHANCED CONVECTIVE SNOW SHOWERS OVER THE SAN JUANS. SOME
OF THIS ACTIVITY STILL IMPACTING PAGOSA SPRINGS...AND THE HIGHER
RESOLUTION RAP MODEL KEEPS SNOW ONGOING INTO THE EVENING HOURS BUT
ENDING BY MID EVENING. REFINED THE WINTER WEATHER ADVISORY FOR
THIS AREA AS CONFIDENCE IS HIGH THAT SNOW WILL HAVE ENDED BY LATE
EVENING. WITH PARTIAL CLEARING OVERNIGHT...TEMPERATURES WILL
PLUNGE AFTER SUNSET AND THEN LEVEL OUT AROUND MIDNIGHT.
UPSTREAM DISTURBANCE OVER MONTANA AND NORTH DAKOTA KEEPS A TROUGH
CARVED OUT OVER WESTERN COLORADO ON NEW YEARS DAY. MOISTURE SOURCE
FOR THIS SHORT WAVE IS CONTINENTAL AND THEREFORE PRECIPITABLE
WATER IS LOW...BUT DOES KEEP THE AIR MASS UNSETTLED DURING THE
LATE MORNING AND EARLY AFTERNOON HOURS. EXPECT SHALLOW CONVECTIVE
SNOW SHOWERS OR FLURRIES TO FORM ACROSS THE HIGH COUNTRY. AREAL
COVERAGE WILL NOT BE WIDESPREAD AND FAVOR NORTH FACING SLOPES.
ESSENTIALLY THIS SHORT WAVE KEEPS THE COLD AIR MASS LOCKED IN.
2013 STARTS THE WAY THAT 2012 ENDED...COLD WITH LITTLE CHANGE.
THE FOLLOWING UPSTREAM WAVE BRUSHES THE PARK/GORE RANGE LATE ON
TUESDAY NIGHT. LIMITED MOISTURE ONCE AGAIN BUT SOME OROGRAPHIC
FLURRIES ARE EXPECTED...OTHERWISE MOSTLY CLEAR WITH STRONG
RADIATIONAL COOLING AS SURFACE HIGH PRESSURE COVERS THE REGION.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 300 PM MST MON DEC 31 2012
IN GENERAL...LOOKS LIKE A MOSTLY DRY LAST HALF OF THE WEEK AS A
BLOCKING RIDGE DEVELOPS OVER THE INTERMOUNTAIN WEST WED AND THU. AS
THIS OCCURS...A SHORTWAVE IN NORTHERLY FLOW CLIPS OUR AREA WED AS
IT DROPS FROM CENTRAL CANADA THROUGH THE PLAINS. LITTLE MOISTURE
ASSOCIATED WITH IT OVER CO...SO WILL CONTINUE WITH JUST A SLIGHT
CHANCE OF SNOW MAINLY NEAR THE CONTINENTAL DIVIDE. LATE IN THE
WEEK...A PACIFIC SHORTWAVE FIGHTS THROUGH/OVER THE RIDGE CROSSING
THE NORTHERN ROCKIES EARLY ON FRIDAY AND BRUSHING BY OUR AREA ON
SATURDAY. AGAIN...LITTLE MOISTURE ASSOCIATED WITH IT IN THE MODELS.
RIDGE REBOUNDS OVER UT/CO BY SUNDAY. ECMWF THEN BRINGS A PROGRESSIVE
PACIFIC TROUGH ACROSS OUR AREA ON MONDAY...WHILE THE GFS INSTEAD
CLOSES OFF A LOW ALONG THE WEST.
THE MAIN CHALLENGE FOR THIS FORECAST PERIOD MAY BE THE VALLEY
TEMPERATURES...WHICH WILL BE SLOW TO WARM. SNOW COVER AND TRAPPED
COLD AIR WITH HIGH PRESSURE AT THE SURFACE WILL PROMOTE SURFACE
INVERSIONS WED-FRI THAT WILL BE DIFFICULT TO DISLODGE. THE WEAK
DISTURBANCES WED AND SAT DON/T LOOK STRONG ENOUGH TO SCOUR OUT MANY
VALLEYS...AND AREAS LIKE THE GRAND VALLEY AND I-70 CORRIDOR WILL SEE
AIR QUALITY SLOWLY DECLINE. HAVE UNDERCUT MOS AND CONSENSUS GUIDANCE
FOR THE VALLEYS AS A RESULT. HIGHER ELEVATIONS... HOWEVER...SHOULD
SEE A SLOW MODERATION IN TEMPS BY THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 904 PM MST MON DEC 31 2012
LOCAL MOUNTAIN OBSCURATIONS WILL CONTINUE OVERNIGHT ACROSS THE
COLORADO MOUNTAINS...MAINLY NEAR THE CONTINENTAL DIVIDE. KASE...
KEGE AND KMTJ WILL CONTINUE TO EXPERIENCE INTERMITTENT LIGHT SNOW
AND THIN FOG WITH MVFR CIGS AND VSBYS. AFTER 09Z...AREAS OF IFR
CIGS AND VSBYS WILL DEVELOP IN VALLEY BOTTOMS...ESPECIALLY NEAR
RIVERS...AS LOW STRATUS AND FOG DEVELOPS. THESE CONDITIONS WILL
DIMINISH AFTER ABOUT 16Z TUESDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...CC
SHORT TERM...PF
LONG TERM...JAD
AVIATION...CC
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
421 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL PROVIDE THE RISK FOR SNOW SHOWERS THROUGH THE
MORNING HOURS. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
BEGINNING THIS AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FRONT IS SLOWLY MOVING INTO NW PA AND WILL CONTINUE IT ARDUOUS
TREK SOUTHWARD. LIGHT SNOW SHOWERS HAVE REDEVELOPED ON THE
SOUTHERN FLANK OF THE BOUNDARY AS A STRONG UPPER LEVEL WAVE IS
RUNNING ALONG THE NORTHERN SIDE OF THE FRONT AND PROVIDING LIFT.
THIS WAVE WILL ALSO HELP TO GET THE FRONT MOVING SOUTHWARD...WHICH
WILL EVENTUALLY PUSH THE LIGHT SNOW SHOWER ACTIVITY TO THE SOUTH.
BY THIS AFTERNOON...THE FRONT WILL HAVE MADE IT INTO THE MID-
ATLANTIC REGION. STRONG CAA AND NORTHWEST FLOW IN THE WAKE OF THE
FRONT WILL KEEP THE AREA BLANKETED WITH CLOUDS. THERE LIKELY BE
SOME LAKE EFFECT/ENHANCED SNOW SHOWERS DEVELOPING LATER TODAY.
HOWEVER DO NOT THINK ACTIVITY WILL BE WIDESPREAD AS INVERSIONS DROP
QUICKLY THIS AFTERNOON. WILL KEEP HIGHEST POPS OVER THE RIDGES AS
THERE IS AN OROGRAPHIC COMPONENT THIS AFTERNOON.
WITH THE STRONG CAA EXPECT STEADY TO SLOWLY FALLING TEMPS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
FLOW ALOFT BEGINS TO WANE TONIGHT...BUT THE COLD AIR WILL CONTINUE
TO PLUNGE INTO THE AREA. STRONG HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST. WILL LEAVE IN CLOUDS OVERNIGHT...BUT WITH INVERSIONS SO
LOW...ONLY EXPECT SNOW SHOWERS IN THE RIDGES.
TEMPS OVERNIGHT WILL BE WELL BELOW NORMAL.
SFC HIGH PRESSURE WILL MOVE FROM THE MIDWEST INTO THE OHIO VALLEY
ON WED. THE CORE OF THE COLD POOL WILL BEGIN TO MOVE NORTHEASTWARD
AS 85H RIDGES MOVE EASTWARD. STILL EXPECT LOTS OF CLOUDS WED...BUT
THERE WILL BE SOME IMPROVEMENT IN THE AFTERNOON.
TEMPS AGAIN...WELL BELOW NORMAL.
ANOTHER SHORTWAVE TROUGH WILL SWING THROUGH LATE THURSDAY.
WITH WINDS VEERING TO THE WEST-SOUTHWEST...TEMPS WILL MODERATE A
BIT ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
GENERAL AGREEMENT IN THE MODELS ON THE OVERALL PATTERN THROUGH THE
LONG TERM PD...ALTHOUGH PREFER GEFS/NAEFS FOR TIMING OF INDIVIDUAL
FEATURES.
A WK COLD FRONT WL MOVE ACRS THE RGN THU NT...HOWEVER DEEP MOISTURE
IS CONFINED WELL TO THE NORTH. COULD SEE A FEW SHSN IN NW FLOW
BEHIND THE FRONT BUT INVERSION SHOULD LIMIT DEPTH OF CLOUDS TO KEEP
ACTIVITY MINIMAL...SO KEPT ONLY LOW CHC POPS N OF PIT. HIGH PRES
BLDS IN SAT BEFORE ANOTHER WK FRONT PASSES THROUGH SAT NT...AGAIN
WITH MOST OF THE MOISTURE STAYING NORTH. THIS SHOULD BRING MAINLY
JUST AN INCREASE IN CLOUDS. HIGH PRES RIDGES BACK IN MON.
TEMPS WL AVG BLW NORMAL MOST OF THE PD. OPERATIONAL MODELS WARM
THINGS UP MON...BUT ENSEMBLES ARE NOT AS AGGRESSIVE. STAYED CLOSER TO
COOLER ENSEMBLE MEANS.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT RAP NAM
AND SREF MODEL OUTPUT SHOW JETSTREAK-RELATED COLD FRONTAL BAND OF
LIGHT IFR SNOW WILL CONTINUE TO PASS EASTWARD THROUGH THE UPPER OHIO
VALLEY THROUGH 13Z.
POSTFRONTAL COLD POOL COUPLED WITH LAKE-MOISTENED WEST TO NORTHWEST
SURFACE LAYER WINDS WILL MAINTAIN MVFR CONDITIONS INTO TONIGHT. ANY
REMAINING PRECIPITATION...BE IT SNOW OR FREEZING DRIZZLE...WILL BE
VERY LIGHT AS SURFACE MIXED LAYER WILL BE CAPPED AT 5 KFT AGL.
SURFACE WINDS WILL BE SOUTHWEST TO WEST AT 12 KTS THROUGH 14Z...THEN
BE MORE WEST TO NORTHWEST AT 10 KTS THE REST OF TODAY AND TONIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
COLD POOL MVFR STRATOCUMULUS WILL REMAIN THROUGH AT LEAST WEDNESDAY.
HIGH PRESSURE SUBSIDENCE MAY PROMOTE A VFR BREAK THURSDAY BEFORE A
COLD FRONT PROVIDES THE NEXT ROUND OF RESTRICTIONS FRIDAY AND
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
112 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL PROVIDE THE RISK FOR SNOW SHOWERS THROUGH THE
MORNING HOURS. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
BEGINNING THIS AFTERNOON.
&&
.NEAR TERM /THROUGH TODAY/...
FRONT IS SLOWLY CROSSING LAKE ERIE AND WILL CONTINUE IT ARDUOUS
TREK SOUTHWARD. MUCH OF THE LIGHT SNOW ACTIVITY HAS DISSIPATED AS
THE UPPER LEVEL WAVE IS NOW OVER EASTERN PA. LATEST HI-RES MODELS
ARE INDICATING THAT ANOTHER AREA OF SNOW SHOWERS WILL DEVELOP
ALONG THE FRONT LATER TONIGHT. IT APPEARS THAT MOST OF THIS NEW
DEVELOPMENT WILL BE OVER THE SOUTHERN HALF OF THE FORECAST AREA.
SNOW SHOWERS ACTIVITY WILL CONTINUE TO BE PUSHED SOUTHWARD THIS
MORNING AS THE FRONT MOVES INTO NORTHERN WV.
BY THIS AFTERNOON...THE FRONT WILL HAVE MADE IT INTO THE MID-
ATLANTIC REGION. STRONG CAA AND NORTHWEST FLOW IN THE WAKE OF THE
FRONT WILL KEEP THE AREA BLANKETED WITH CLOUDS. THERE LIKELY BE
SOME LAKE EFFECT/ENHANCED SNOW SHOWERS DEVELOPING LATER TODAY.
HOWEVER DO NOT THINK ACTIVITY WILL BE WIDESPREAD AS INVERSIONS DROP
QUICKLY THIS AFTERNOON. WILL KEEP HIGHEST POPS OVER THE RIDGES AS
THERE IS AN OROGRAPHIC COMPONENT THIS AFTERNOON.
WITH THE STRONG CAA EXPECT STEADY TO SLOWLY FALLING TEMPS TODAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
FLOW ALOFT BEGINS TO WANE TONIGHT...BUT THE COLD AIR WILL CONTINUE
TO PLUNGE INTO THE AREA. STRONG HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST. WILL LEAVE IN CLOUDS OVERNIGHT...BUT WITH INVERSIONS SO
LOW...ONLY EXPECT SNOW SHOWERS IN THE RIDGES.
TEMPS OVERNIGHT WILL BE WELL BELOW NORMAL.
SFC HIGH PRESSURE WILL MOVE FROM THE MIDWEST INTO THE OHIO VALLEY
ON WED. THE CORE OF THE COLD POOL WILL BEGIN TO MOVE NORTHEASTWARD
AS 85H RIDGES MOVE EASTWARD. STILL EXPECT LOTS OF CLOUDS WED...BUT
THERE WILL BE SOME IMPROVEMENT IN THE AFTERNOON.
TEMPS AGAIN...WELL BELOW NORMAL.
ANOTHER SHORTWAVE TROUGH WILL SWING THROUGH LATE THURSDAY.
WITH WINDS VEERING TO THE WEST-SOUTHWEST...TEMPS WILL MODERATE A
BIT ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
GENERAL AGREEMENT IN THE MODELS ON THE OVERALL PATTERN THROUGH THE
LONG TERM PD...ALTHOUGH PREFER GEFS/NAEFS FOR TIMING OF INDIVIDUAL
FEATURES.
A WK COLD FRONT WL MOVE ACRS THE RGN THU NT...HOWEVER DEEP MOISTURE
IS CONFINED WELL TO THE NORTH. COULD SEE A FEW SHSN IN NW FLOW
BEHIND THE FRONT BUT INVERSION SHOULD LIMIT DEPTH OF CLOUDS TO KEEP
ACTIVITY MINIMAL...SO KEPT ONLY LOW CHC POPS N OF PIT. HIGH PRES
BLDS IN SAT BEFORE ANOTHER WK FRONT PASSES THROUGH SAT NT...AGAIN
WITH MOST OF THE MOISTURE STAYING NORTH. THIS SHOULD BRING MAINLY
JUST AN INCREASE IN CLOUDS. HIGH PRES RIDGES BACK IN MON.
TEMPS WL AVG BLW NORMAL MOST OF THE PD. OPERATIONAL MODELS WARM
THINGS UP MON...BUT ENSEMBLES ARE NOT AS AGGRESSIVE. STAYED CLOSER TO
COOLER ENSEMBLE MEANS.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT RAP NAM
AND SREF MODEL OUTPUT SHOW JETSTREAK-RELATED COLD FRONTAL BAND OF
LIGHT IFR SNOW WILL PASS EASTWARD THROUGH THE UPPER OHIO VALLEY
THROUGH 13Z.
POSTFRONTAL COLD POOL COUPLED WITH LAKE-MOISTENED WEST TO NORTHWEST
SURFACE LAYER WINDS WILL MAINTAIN MVFR CONDITIONS INTO TONIGHT.
NAM MODEL PROFILES SHOW THE SURFACE MIXED LAYER WILL BE CAPPED AT
5 KFT AGL WITH CLOUD TOP TEMPERATURES POSSIBLY WARMER THAN
-10C. SO ANY REMAINING PRECIPITATION WILL BE VERY LIGHT...BE IT
VERY LIGHT SNOW OR VERY LIGHT FREEZING DRIZZLE.
SURFACE WINDS WILL BE SOUTHWEST TO WEST AT 12 KTS THROUGH 14Z...THEN
BE MORE WEST TO NORTHWEST AT 10 KTS THE REST OF TODAY AND TONIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
COLD POOL MVFR STRATOCUMULUS WILL REMAIN THROUGH AT LEAST WEDNESDAY.
HIGH PRESSURE SUBSIDENCE MAY PROMOTE A VFR BREAK THURSDAY BEFORE A
COLD FRONT PROVIDES THE NEXT ROUND OF RESTRICTIONS FRIDAY AND
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1201 AM CST TUE JAN 1 2013
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION.../ISSUED 836 PM CST MON DEC 31 2012/
UPDATE...
TEMPERATURES AT 8 PM HAVE ALREADY FALLEN TO BETWEEN 5 AND 10 BELOW
ZERO ACROSS WRN MN...WITH SINGLE DIGITS ABOVE ZERO FURTHER EAST
ACROSS THE TWIN CITIES METRO AND WRN WI. THE RIDGE IS CENTERED
OVER WRN MN ATTM AND IS EXPECTED TO CONTINUE BUILDING SEWD TO SCTRL
MN BY DAWN.
A BANK OF STRATUS OVER SD HAS INCHED ITS WAY EWD TO THE MN STATE
LINE. TEMPERATURES WARMED SEVERAL DEGREES OVER ERN SD AS THIS
STRATUS MOVED OVERHEAD. THUS...COULD SEE TEMPS MODERATE
OVERNIGHT ACROSS FAR WRN MN AS THIS STRATUS MOVES IN. JUST A BIT
FURTHER EAST...IDEAL RADIATIONAL CONDITIONS WILL PERSIST DIRECTLY
UNDER THE RIDGE AND TEMPERATURES ARE EXPECTED TO PLUMMET TO 15 TO
20 BELOW IN MANY PLACES. WINDS MAY REMAIN JUST ELEVATED ENOUGH
OVER WRN WI TO PREVENT FROM REACHING 10 BELOW. THE URBAN HEAT
ISLAND OF THE METRO WILL ALSO KEEP TEMPERATURES IN THE SINGLE
DIGITS BELOW THERE.
WIND HAS WEAKENED QUITE A BIT IN THE PAST COUPLE HOURS AND THERE
ARE DOUBTS THAT WIDESPREAD WIND CHILLS WILL REACH 25 BELOW.
HOWEVER...BY DAWN A RETURN FLOW WILL BEGIN WITH WINDS REACHING 5 KTS
AGAIN. WITH SUCH COLD CONDITIONS IN PLACE...IT WON/T TAKE MUCH
WIND TO OCCASIONALLY REACH WIND CHILLS OF 25 BELOW SO WILL
MAINTAIN THE WIND CHILL ADVISORY.
BORGHOFF
&&
.PREV DISCUSSION.../ISSUED 257 PM CST MON DEC 31 2012/
ANOTHER COLD NIGHT TONIGHT AS HIGH PRESSURE SETTLES ACROSS THE
REGION. A WEAK CLIPPER SYSTEM WILL BRING SOME LIGHT SNOW ON
WEDNESDAY...BUT ACCUMULATIONS WILL BE LIGHT. THE REST OF THE
FORECAST WILL BE DRY...WITH A WARM UP EXPECTED THIS WEEKEND WITH
HIGH TEMPERATURES APPROACHING THE THAWING MARK FOR SUNDAY AND
MONDAY.
TODAY THROUGH WEDNESDAY...THE TWO MAIN CHALLENGES WERE LOW
TEMPERATURES TONIGHT...AND HOW TO BEST CONVEY THE LIGHT PRECIP ON
WEDNESDAY. FIRST OF ALL...TONIGHTS LARGE SCALE SET UP IS IDEAL FOR
NOCTURNAL COOLING AS THE SURFACE HIGH SLIDES SOUTHEAST ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY REGION. LIGHT WINDS...CLEAR
SKIES...AND AMPLE SNOW COVER WILL ALLOW TEMPERATURES TO COOL OFF
RATHER QUICKLY AFTER SUNSET. HAVE EXPANDED THE WIND CHILL ADVISORY
ACROSS THE NORTH WHERE COULD SEE VALUES AROUND -25F OVERNIGHT. THE
ONE CAVEAT...ASIDE FROM THE LIGHT WINDS...IS A SUBTLE SHORTWAVE
ACROSS THE WESTERN DAKOTAS AND THE DOWNSTREAM CLOUDS ACROSS THE
CENTRAL DAKOTAS...WHICH WILL HOLD UP TEMPERATURES IF THEY MOVE
OVERHEAD TONIGHT. THESE WILL MOST LIKELY AFFECT SOUTHWEST
MINNESOTA...BUT DID NOT CANCEL ANY OF THE WIND CHILL ADVISORY
SINCE THERE IS STILL POTENTIAL FOR SUBSTANTIAL COOLING
OVERNIGHT...AND IT IS NEW YEARS EVE. AFTER A CHILLY DRY
TUESDAY...A WEAKENING SHORTWAVE WILL SPREAD A BROAD AREA OF UPWARD
FORCING ACROSS THE REGION...AND FORECAST SOUNDINGS SHOW SATURATION
WITH WEAK LIFT...WHICH SHOULD BE ENOUGH TO PRODUCE LIGHT SNOW ON
WEDNESDAY. LIQUID AMOUNTS WILL BE ON THE ORDER OF A COUPLE OF
HUNDREDTHS OR SO...BUT RATIOS SHOULD BE NEAR 20:1. THEREFORE HAVE
SNOWFALL TOTALS OF AROUND A HALF INCH TO A INCH FOR
WEDNESDAY...WITH LIKELY POPS. THE UPSTREAM WAVE BREAKING TO THE
NORTH...AND STRONG ZONAL JET ACROSS THE OHIO RIVER VALLEY WILL
SHEAR OUT THIS SYSTEM...SO IT WILL BECOME LESS ORGANIZED AS IT
TRAVERSES THE REGION. HOWEVER...DECIDED TO GO WITH LIKELY
POPS...SINCE IT WILL SNOW ON WEDNESDAY...BUT HAVE LIGHT QPF
AMOUNTS SINCE MEASURABLE PRECIP IS STILL SOMEWHAT QUESTIONABLE.
THURSDAY THROUGH MONDAY...TOWARDS THE END OF THE WEEK THE UPPER
LEVEL FLOW WILL TRANSITION FROM NORTHWESTERLY TO MORE WESTERLY
ACROSS THE MONTANA/CANADA BORDER. THIS WILL LEAD TO SIGNIFICANT LEE
SIDE WARMING OVER THE HIGH PLAINS...WHICH WILL BE ADVECTED ACROSS
THE REGION FOR THE WEEKEND. H900 TEMPERATURES OF +3 TO +5C WILL
SET THE STAGE FOR A WARM UP ON SUNDAY AND MONDAY. FOR NOW IT
APPEARS THE LOW LEVEL INVERSION WILL MITIGATE ANY SIGNIFICANT
SNOW MELT...BUT SHOULD SEE TEMPERATURES APPROACH THE 32F MARK. A
FEW WEAK WAVES TRACK ACROSS THE NORTH...BUT FOR NOW HAVE LEFT THE
EXTENDED FORECAST DRY.
&&
.AVIATION.../06Z TAF ISSUANCE/
CANADIAN HIGH PRESSURE CENTERED OVER SOUTHERN MINNESOTA HAS LED TO
CLEAR SKIES AND NEARLY CALM WINDS ACROSS ALL THE TAF SITES LATE
THIS EVENING. WIDESPREAD MVFR STRATUS ON THE BACK SIDE OF THE
RIDGE OVER THE DAKOTAS HAS BEEN INCHING EASTWARD INTO SWRN MN
DURING THE PAST COUPLE OF HOURS. MODELS REMAIN AT ODDS WITH THE
EVOLUTION OF THIS STRATUS WITH SOME SHOWING IT REMAINING TO THE
WEST AND OTHERS SHOWING IT BUILDING EASTWARD OVERNIGHT AND TUESDAY
BEHIND THE RIDGE. WILL SIDE WITH THE PREVIOUS FORECAST AND BUILD
IT EASTWARD THROUGH THE PERIOD GIVEN THE GOOD REPRESENTATION OF
CURRENT CLOUD COVER THOSE MODELS HAVE AT THE PRESENT TIME.
KMSP...BIGGEST CONCERNS WILL BE WHETHER THE STRATUS TO THE WEST CAN
MAKE IT AS FAR EAST AS MSP AND WHEN IT WOULD ARRIVE. SIMPLE
EXTRAPOLATION OF CURRENT TRENDS WOULDN/T BRING THE CLOUDS IN
UNTIL TUESDAY EVENING. HOWEVER...THINK EASTWARD EXPANSION WILL
ACCELERATE AS THE RIDGE PUSHES TO THE SOUTH SO FAVORED TIMING OF
THE PREVIOUS FORECAST AND OF THE RAP MODEL. FORECAST SOUNDINGS
SHOW GOOD SATURATION BETWEEN 020-030...SO INTRODUCED MVFR CIGS FOR
TUESDAY AFTERNOON INTO EVENING.
/OUTLOOK FOR KMSP/
WED...MVFR CONDITIONS/-SN POSSIBLE. WSW WINDS 4 TO 8 KTS.
THU...MVFR CEILINGS/FLURRIES POSSIBLE. NW WINDS 8 TO 12 KTS.
FRI...VFR. WINDS SW 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 9 AM CST TUESDAY FOR BENTON-BLUE EARTH-
BROWN-CHIPPEWA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-ISANTI-
KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-
MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-REDWOOD-RENVILLE-
RICE-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-
WASECA-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
JRB/BORGHOFF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
126 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL PASS THROUGH THE REGION LATE TONIGHT BRINGING
SCATTERED SNOW SHOWERS AND FLURRIES. LITTLE SNOW IS EXPECTED BUT
OVER ONEIDA, ONONDAGA AND MADISON COUNTIES, 1 TO 3 INCHES IS
POSSIBLE. LAKE EFFECT SNOW SHOWERS WILL DROP SOUTH ACROSS CENTRAL
NEW YORK ON WEDNESDAY WHILE WEAKENING. ANOTHER FRONT WILL PUSH
THROUGH THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
BRINGING ANOTHER ROUND OF SCATTERED SNOW SHOWERS AND LAKE EFFECT
SNOWS.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1245 AM UPDATE...
ORGANIZED LK BAND HAS DROPPED INTO NRN ONEIDA CNTY ATTM, JUST AHD
OF THE SFC FRONT. KTYX VWP INDICATES FLOW IS ALIGNED FM 3KFT-9KFT
OUT OF THE WEST AND THIS ACCNTS FOR THE MORE ORGANIZED NATURE OF
THE BAND. THINKING IS THAT AS CDFNT DROPS THRU THE REGION, BAND WL
BCM MORE DISORGANIZED WITH MINIMAL ACCUMS EXPECTED. HV UPDATED
HRLY POPS AND WX GRIDS TO ACCNT FOR THE CURRENT RADAR TRENDS. ALSO
ADJUSTED HRLY T/TD VALUES.
PREV DISCOS BLO...
940 PM UPDATE...
QUICK UPDATE TO ACCOUNT FOR LATEST TRENDS. LATEST RADAR DATA
SHOWING A BAND OF SNOW EXTENDING EAST ACROSS THE SOUTHERN TIER
THIS EVENING WITH SNOW JUST BEGINNING HERE AT THE AIRFIELD. IN ALL
ACTUALITY...FAIRLY DECENT FORCING FOR ONGOING SNOWFALL AS REGION
RESIDES UNDER THE LEFT EXIT REGION OF A 200+ KT UPPER JETSTREAK TO
OUR SOUTH. THE 00Z KPIT SOUNDING MEASURED 180 KTS AT ROUGHLY
230-MB WHICH MAY BE ONE OF THE STRONGER JETS OF THE SEASON SO FAR.
FURTHER TO OUR NORTH...A MID-LEVEL 500-MB JET ROUNDING THE BASE OF
AN UPPER TROUGH ACROSS EASTERN ONTARIO IS ALSO PROVIDING A
GLANCING BLOW WITH THE FCST AREA BECOMING MORE IN LINE WITH THE
RIGHT ENTRANCE REGION OF THIS MID-LEVEL FEATURE. AND IF THAT WERE
NOT ENOUGH...SFC FIELDS FROM THE RUC AND MSAS INDICATE A WEAK PRE-
FRONTAL TROUGH AND MID-LEVEL VORT MAX APPROACHING FROM EASTERN OH.
SO WHAT DOES THIS MEAN...WELL WE CAN EXPECT SNOW TO CONTINUE
DEVELOPING OVERNIGHT AS MAIN COLD FRONT CONTINUES TO APPROACH.
LATEST LOOK STILL SHOWS THE FRONT RESIDING TO THE WEST OF BUFFALO
THIS EVENING WITH A NOTABLE TEMP INCREASE DETECTED DOWNSTREAM
ACROSS OUR AREA. IN FACT...SEVERAL SITES HAVE SEEN A SLIGHT
INCREASE IN TEMPS AS PRE-FRONTAL THERMAL RIDGING MOVES OVERHEAD.
WILL HOLD OFF ON MAKING ANY WHOLESALE CHANGES TO OVERNIGHT LOWS AS
COLD AIR ADVECTION FOLLOWING FROPA WILL ALLOW TEMPS TO COOL
APPROPRIATELY. FOLLOWING FROPA...WINDS WILL BECOME ALIGNED ON A
NORTHWESTERLY CONFIGURATION WHICH COMBINED WITH 850-MB TEMPS
DROPPING TO NEAR -14C BY 12Z TUE...WILL RESULT IN DEVELOPING LAKE
EFFECT SNOWS SOUTHEAST OF LAKE ONTARIO. WITH FLOW EXPECTED TO BE
FAIRLY CHAOTIC IN NATURE...DEVELOPING BANDS WILL BE ON THE MOVE
FOR A GOOD PORTION OF THE EARLY MORNING HRS WHICH SHOULD KEEP
ACCUMULATIONS IN CHECK. NO ADDITIONAL CHANGES NEEDED FOR THE TIME
BEING.
7 PM UPDATE...
ONLY REAL CHANGE REQUIRED WAS TO DELAY SNOW INITIATION TIME AS
MAIN COLD FRONT IS STILL POSITIONED ACROSS SOUTH-CENTRAL ONTARIO
THIS HR. UPSTREAM RADAR TRENDS FROM KBUF BEGINNING TO SHOW SNOW
SHOWER DEVELOPMENT ACROSS THE WESTERN SOUTHERN TIER WITH OLEAN NOW
REPORTING LGT SNOW. THIS ACTIVITY APPEARS TO BE FROM A PRE-FRONTAL
TROUGH MOVING EAST AHEAD OF THE PRIMARY FRONT. ALOFT...LATEST
WATER VAPOR IMAGERY SHOWING VERY LITTLE SUPPORT ALOFT AS MAIN
SHORTWAVE ENERGY LAGGING WELL TO THE WEST ACROSS EASTERN LAKE
HURON. AS WE PROGRESS THROUGH THE OVERNIGHT...EXPECT SNOW SHWR
ACTIVITY TO INCREASE IN COVERAGE AS AFOREMENTIONED FRONT AND PRE-
FRONTAL TROUGH SHIFT EAST WITH TIME. FOLLOWING THEIR PASSAGE...
LOW-LEVEL FLOW WILL BECOME ALIGNED TO SUPPORT DEVELOPING LAKE
EFFECT ACROSS THE NORTHERN CWA WHERE A FEW INCHES OF NEW SNOW WILL
BE POSSIBLE BY MORNING. ASIDE FROM THAT...NO SIGNIFICANT CHANGES
REQUIRED AT THIS TIME.
AT 4 PM...MID/HIGH LEVEL CLOUDS CONTINUE STREAMING ACROSS THE
AREA UNDER SOUTHWEST FLOW. AFTERNOON TEMPS ARE CURRENTLY IN THE
UPPER 20S TO MID 30S.
SKIES WILL BECOME CLOUDY THIS EVENING AS A SFC TROF OVER SOUTHERN
ONTARIO APPROACHES THE AREA WHILE MOISTURE ALSO INCREASES FROM THE
SOUTH DUE TO A SYSTEM IN THE SOUTHERN PLAINS. AS THE SFC TROF
STARTS DROPPING SOUTH THROUGH THE AREA LATER THIS EVENING LOW
LEVEL FLOW WILL ALSO BECOME FAVORABLE FOR LAKE ENHANCEMENT.
SHORTLY AFTER MIDNIGHT WENT WITH LIKELY POPS ACROSS THE FAR NRN
CWA AND WITH LOW LEVEL FLOW CONTINUING TO VEER BAND OF HEAVIER
ACTIVITY WILL CONTINUE DROPPING SOUTH THROUGH DAYBREAK. DUE TO
BAND SHIFTING SOUTH WITH TIME, SNOW ACCUMS WILL REMAIN FAIRLY
MINOR WITH 1 TO 3 INCHES POSSIBLE ACROSS ONONDAGA, MADISON AND
ONEIDA COUNTIES. FOR THE REST OF THE REGION JUST SCATTERED SNOW
SHOWERS AND FLURRIES ARE EXPECTED WITH ACCUMS WELL LESS THAN AN
INCH. OVERNIGHT LOWS WILL RANGE IN THE 20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
TUESDAY...FOLLOWING THE FRONT, NORTHWEST FLOW WILL PERSIST OVER
THE REGION WITH SCATTERED SNOW SHOWERS CONTINUING OVER CENTRAL
NY UNDER 300/310 LOW LEVEL FLOW. ABUNDANT LOW LEVEL MOISTURE AND
COLD AIR ADVECTION WILL BRING PLENTY OF CLOUDS AND TEMPS WILL
STRUGGLE TO RISE JUST A FEW DEGREES FROM THE OVERNIGHT LOWS.
TUESDAY NIGHT...LOW LEVEL FLOW WILL BACK IN RESPONSE TO NEXT SFC
TROF DROPPING SOUTH FROM CANADA. ANY LINGERING SNOW SHOWERS WILL
LIFT NORTH AND WEAKEN DURING THE EVENING HOURS. TOWARD DAYBREAK
SFC TROF WILL EXTEND ACROSS LAKE ONTARIO BRINGING A FAVORABLE
FLOW FOR THE EASTERN SHORE INTO NORTHERN ONEIDA COUNTY. WILL
INCREASE POPS HERE TO LIKELY TOWARD DAYBREAK.
WEDNESDAY...SFC TROF WILL SWING THROUGH AREA DURING THE MORNING
HOURS WITH SFC HIGH PRES NOSING DOWN FROM EASTERN CANADA BY
AFTERNOON. LOW LEVEL FLOW LOOKS FAVORABLE FOR LES ACROSS NRN CWA
THROUGH MID MORNING WITH POSSIBLE GEORGIAN BAY CONNECTION BUT
WITH FLOW CONTINUING TO VEER THIS SHOULD LIMIT SNOW ACCUM. BY
AFTERNOON, 310 LOW LEVEL FLOW WILL KEEP THE MOST PERSISTENT SNOW
SHOWERS ACROSS THE FINGER LAKES AND NORTHERN SUSQUEHANNA REGION.
WED NIGHT/THURSDAY...ANOTHER SYSTEM MOVING THROUGH SOUTHERN CANADA
WILL BACK LOW LEVEL FLOW PUSHING ANY LINGERING SNOW SHOWERS ACROSS
CNTRL NY NORTH WHILE WEAKENING. ON THURSDAY, SFC TROF WILL
CROSS NEARBY SOUTHERN ONTARIO BY LATE DAY BRINGING THE CHC FOR
SNOW SHOWERS PRIMARILY IN THE NRN/WRN FA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
130 PM UPDATE...
FAIRLY QUIET EXTENDED PERIOD WITH A FEW SHOTS AT LIGHT SNOWS BUT
NO MAJOR STORMS IN THE OFFERING. FIRST SHOT AT SNOW COMES THURSDAY
NIGHT INTO FRIDAY WITH A COLD FRONT AND REINFORCING SHOT OF COLD
AIR. A FEW DAYS AGO THIS COLD PUSH WAS MUCH MORE IMPRESSIVE BUT IT
NOW LOOKS LIKE THE CORE WILL STAY TO OUR NORTH INTO QUEBEC. STILL
850 TEMPS ON BOTH THE GFS AND EURO ARE IN THE MID TEENS BELOW ZERO
WHICH WILL KEEP HIGHS IN THE 20S/NIGHTTIME LOWS IN THE TEENS WITH
SOME SINGLE DIGITS POSSIBLE OVER OUR COLDER SECTIONS TO THE EAST.
DESPITE NORTHWEST WINDS A SHOT OF LAKE EFFECT DOES NOT LOOK OVERLY
IMPRESSIVE WITH DRY AIR BEING THE MAIN NEGATING FACTOR. BOTH THE
GFS AND EURO SUGGEST TEMPS WARM UP A BIT SATURDAY...BEFORE ANOTHER
SYSTEM BRINGS US LIGHT SNOW SATURDAY NIGHT INTO SUNDAY...WITH MORE
SEASONABLE AIR.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
MVFR CIGS ARE EXPECTED TO BE THE GENERAL RESTRICTION CATEGORY
EARLY THIS MORNING ACROSS THE UPSTATE NY TERMINALS WITH VFR OVER
NORTHEAST PENNSYLVANIA. A BAND OF LAKE EFFECT SNOW WILL PASS
QUICKLY THROUGH KRME AND INTO THE KSYR AREA PRIOR TO 09Z WITH
OCCASIONAL IFR VSBY RESTRICTIONS. ELSEWHERE...AREAS OF LIGHT
FLURRIES MAY BRING ADDITIONAL MVFR VSBY RESTRICTIONS TO KBGM AND
KITH. THE SNOW BAND BECOMES A BROAD PLUME OF LIGHT SNOW SPREADING
DOWNWIND THROUGH KSYR-KITH-KBGM THROUGH THE AFTERNOON...ALTHOUGH DRYING
AND CONVECTIVE MIXING SHOULD HELP TO LIFT CIGS TO VFR WITH OCCASIONAL
MINOR MVFR VSBY RESTRICTIONS WITHIN SNOW SHOWERS. FURTHER DRYING
TONIGHT WILL ALLOW SNOW BAND TO RETRACT TOWARD THE LAKE AND BECOME
MORE OF A WEST-EAST INFLUENCE AGAIN THROUGH KSYR-KRME AFT 00Z WITH
RESTRICTIONS MAINLY EXPECTED TO BE MVFR. A RETURN TO VFR IS
EXPECTED ELSEWHERE.
WINDS SW 5-15 KTS BECOME NW 10G15 KTS BY 15Z...CONTINUING UNTIL
THIS EVENING WHEN SPEEDS DIMINISH TO 5-10 KTS FROM THE NW.
OUTLOOK...
WED/WED NGT...OCCASIONAL MVFR/IFR FOR NY TERMINALS IN SNOW SHOWERS.
THU THROUGH SAT...MAINLY VFR. RESTRICTIONS ARE POSSIBLE AT
KRME/KSYR IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM
NEAR TERM...CMG/PVN/RRM
SHORT TERM...RRM
LONG TERM...HEDEN
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1249 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL PASS THROUGH THE REGION LATE TONIGHT BRINGING
SCATTERED SNOW SHOWERS AND FLURRIES. LITTLE SNOW IS EXPECTED BUT
OVER ONEIDA, ONONDAGA AND MADISON COUNTIES, 1 TO 3 INCHES IS
POSSIBLE. LAKE EFFECT SNOW SHOWERS WILL DROP SOUTH ACROSS CENTRAL
NEW YORK ON WEDNESDAY WHILE WEAKENING. ANOTHER FRONT WILL PUSH
THROUGH THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
BRINGING ANOTHER ROUND OF SCATTERED SNOW SHOWERS AND LAKE EFFECT
SNOWS.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1245 AM UPDATE...
ORGANIZED LK BAND HAS DROPPED INTO NRN ONEIDA CNTY ATTM, JUST AHD
OF THE SFC FRONT. KTYX VWP INDICATES FLOW IS ALIGNED FM 3KFT-9KFT
OUT OF THE WEST AND THIS ACCNTS FOR THE MORE ORGANIZED NATURE OF
THE BAND. THINKING IS THAT AS CDFNT DROPS THRU THE REGION, BAND WL
BCM MORE DISORGANIZED WITH MINIMAL ACCUMS EXPECTED. HV UPDATED
HRLY POPS AND WX GRIDS TO ACCNT FOR THE CURRENT RADAR TRENDS. ALSO
ADJUSTED HRLY T/TD VALUES.
PREV DISCOS BLO...
940 PM UPDATE...
QUICK UPDATE TO ACCOUNT FOR LATEST TRENDS. LATEST RADAR DATA
SHOWING A BAND OF SNOW EXTENDING EAST ACROSS THE SOUTHERN TIER
THIS EVENING WITH SNOW JUST BEGINNING HERE AT THE AIRFIELD. IN ALL
ACTUALITY...FAIRLY DECENT FORCING FOR ONGOING SNOWFALL AS REGION
RESIDES UNDER THE LEFT EXIT REGION OF A 200+ KT UPPER JETSTREAK TO
OUR SOUTH. THE 00Z KPIT SOUNDING MEASURED 180 KTS AT ROUGHLY
230-MB WHICH MAY BE ONE OF THE STRONGER JETS OF THE SEASON SO FAR.
FURTHER TO OUR NORTH...A MID-LEVEL 500-MB JET ROUNDING THE BASE OF
AN UPPER TROUGH ACROSS EASTERN ONTARIO IS ALSO PROVIDING A
GLANCING BLOW WITH THE FCST AREA BECOMING MORE IN LINE WITH THE
RIGHT ENTRANCE REGION OF THIS MID-LEVEL FEATURE. AND IF THAT WERE
NOT ENOUGH...SFC FIELDS FROM THE RUC AND MSAS INDICATE A WEAK PRE-
FRONTAL TROUGH AND MID-LEVEL VORT MAX APPROACHING FROM EASTERN OH.
SO WHAT DOES THIS MEAN...WELL WE CAN EXPECT SNOW TO CONTINUE
DEVELOPING OVERNIGHT AS MAIN COLD FRONT CONTINUES TO APPROACH.
LATEST LOOK STILL SHOWS THE FRONT RESIDING TO THE WEST OF BUFFALO
THIS EVENING WITH A NOTABLE TEMP INCREASE DETECTED DOWNSTREAM
ACROSS OUR AREA. IN FACT...SEVERAL SITES HAVE SEEN A SLIGHT
INCREASE IN TEMPS AS PRE-FRONTAL THERMAL RIDGING MOVES OVERHEAD.
WILL HOLD OFF ON MAKING ANY WHOLESALE CHANGES TO OVERNIGHT LOWS AS
COLD AIR ADVECTION FOLLOWING FROPA WILL ALLOW TEMPS TO COOL
APPROPRIATELY. FOLLOWING FROPA...WINDS WILL BECOME ALIGNED ON A
NORTHWESTERLY CONFIGURATION WHICH COMBINED WITH 850-MB TEMPS
DROPPING TO NEAR -14C BY 12Z TUE...WILL RESULT IN DEVELOPING LAKE
EFFECT SNOWS SOUTHEAST OF LAKE ONTARIO. WITH FLOW EXPECTED TO BE
FAIRLY CHAOTIC IN NATURE...DEVELOPING BANDS WILL BE ON THE MOVE
FOR A GOOD PORTION OF THE EARLY MORNING HRS WHICH SHOULD KEEP
ACCUMULATIONS IN CHECK. NO ADDITIONAL CHANGES NEEDED FOR THE TIME
BEING.
7 PM UPDATE...
ONLY REAL CHANGE REQUIRED WAS TO DELAY SNOW INITIATION TIME AS
MAIN COLD FRONT IS STILL POSITIONED ACROSS SOUTH-CENTRAL ONTARIO
THIS HR. UPSTREAM RADAR TRENDS FROM KBUF BEGINNING TO SHOW SNOW
SHOWER DEVELOPMENT ACROSS THE WESTERN SOUTHERN TIER WITH OLEAN NOW
REPORTING LGT SNOW. THIS ACTIVITY APPEARS TO BE FROM A PRE-FRONTAL
TROUGH MOVING EAST AHEAD OF THE PRIMARY FRONT. ALOFT...LATEST
WATER VAPOR IMAGERY SHOWING VERY LITTLE SUPPORT ALOFT AS MAIN
SHORTWAVE ENERGY LAGGING WELL TO THE WEST ACROSS EASTERN LAKE
HURON. AS WE PROGRESS THROUGH THE OVERNIGHT...EXPECT SNOW SHWR
ACTIVITY TO INCREASE IN COVERAGE AS AFOREMENTIONED FRONT AND PRE-
FRONTAL TROUGH SHIFT EAST WITH TIME. FOLLOWING THEIR PASSAGE...
LOW-LEVEL FLOW WILL BECOME ALIGNED TO SUPPORT DEVELOPING LAKE
EFFECT ACROSS THE NORTHERN CWA WHERE A FEW INCHES OF NEW SNOW WILL
BE POSSIBLE BY MORNING. ASIDE FROM THAT...NO SIGNIFICANT CHANGES
REQUIRED AT THIS TIME.
AT 4 PM...MID/HIGH LEVEL CLOUDS CONTINUE STREAMING ACROSS THE
AREA UNDER SOUTHWEST FLOW. AFTERNOON TEMPS ARE CURRENTLY IN THE
UPPER 20S TO MID 30S.
SKIES WILL BECOME CLOUDY THIS EVENING AS A SFC TROF OVER SOUTHERN
ONTARIO APPROACHES THE AREA WHILE MOISTURE ALSO INCREASES FROM THE
SOUTH DUE TO A SYSTEM IN THE SOUTHERN PLAINS. AS THE SFC TROF
STARTS DROPPING SOUTH THROUGH THE AREA LATER THIS EVENING LOW
LEVEL FLOW WILL ALSO BECOME FAVORABLE FOR LAKE ENHANCEMENT.
SHORTLY AFTER MIDNIGHT WENT WITH LIKELY POPS ACROSS THE FAR NRN
CWA AND WITH LOW LEVEL FLOW CONTINUING TO VEER BAND OF HEAVIER
ACTIVITY WILL CONTINUE DROPPING SOUTH THROUGH DAYBREAK. DUE TO
BAND SHIFTING SOUTH WITH TIME, SNOW ACCUMS WILL REMAIN FAIRLY
MINOR WITH 1 TO 3 INCHES POSSIBLE ACROSS ONONDAGA, MADISON AND
ONEIDA COUNTIES. FOR THE REST OF THE REGION JUST SCATTERED SNOW
SHOWERS AND FLURRIES ARE EXPECTED WITH ACCUMS WELL LESS THAN AN
INCH. OVERNIGHT LOWS WILL RANGE IN THE 20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
TUESDAY...FOLLOWING THE FRONT, NORTHWEST FLOW WILL PERSIST OVER
THE REGION WITH SCATTERED SNOW SHOWERS CONTINUING OVER CENTRAL
NY UNDER 300/310 LOW LEVEL FLOW. ABUNDANT LOW LEVEL MOISTURE AND
COLD AIR ADVECTION WILL BRING PLENTY OF CLOUDS AND TEMPS WILL
STRUGGLE TO RISE JUST A FEW DEGREES FROM THE OVERNIGHT LOWS.
TUESDAY NIGHT...LOW LEVEL FLOW WILL BACK IN RESPONSE TO NEXT SFC
TROF DROPPING SOUTH FROM CANADA. ANY LINGERING SNOW SHOWERS WILL
LIFT NORTH AND WEAKEN DURING THE EVENING HOURS. TOWARD DAYBREAK
SFC TROF WILL EXTEND ACROSS LAKE ONTARIO BRINGING A FAVORABLE
FLOW FOR THE EASTERN SHORE INTO NORTHERN ONEIDA COUNTY. WILL
INCREASE POPS HERE TO LIKELY TOWARD DAYBREAK.
WEDNESDAY...SFC TROF WILL SWING THROUGH AREA DURING THE MORNING
HOURS WITH SFC HIGH PRES NOSING DOWN FROM EASTERN CANADA BY
AFTERNOON. LOW LEVEL FLOW LOOKS FAVORABLE FOR LES ACROSS NRN CWA
THROUGH MID MORNING WITH POSSIBLE GEORGIAN BAY CONNECTION BUT
WITH FLOW CONTINUING TO VEER THIS SHOULD LIMIT SNOW ACCUM. BY
AFTERNOON, 310 LOW LEVEL FLOW WILL KEEP THE MOST PERSISTENT SNOW
SHOWERS ACROSS THE FINGER LAKES AND NORTHERN SUSQUEHANNA REGION.
WED NIGHT/THURSDAY...ANOTHER SYSTEM MOVING THROUGH SOUTHERN CANADA
WILL BACK LOW LEVEL FLOW PUSHING ANY LINGERING SNOW SHOWERS ACROSS
CNTRL NY NORTH WHILE WEAKENING. ON THURSDAY, SFC TROF WILL
CROSS NEARBY SOUTHERN ONTARIO BY LATE DAY BRINGING THE CHC FOR
SNOW SHOWERS PRIMARILY IN THE NRN/WRN FA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
130 PM UPDATE...
FAIRLY QUIET EXTENDED PERIOD WITH A FEW SHOTS AT LIGHT SNOWS BUT
NO MAJOR STORMS IN THE OFFERING. FIRST SHOT AT SNOW COMES THURSDAY
NIGHT INTO FRIDAY WITH A COLD FRONT AND REINFORCING SHOT OF COLD
AIR. A FEW DAYS AGO THIS COLD PUSH WAS MUCH MORE IMPRESSIVE BUT IT
NOW LOOKS LIKE THE CORE WILL STAY TO OUR NORTH INTO QUEBEC. STILL
850 TEMPS ON BOTH THE GFS AND EURO ARE IN THE MID TEENS BELOW ZERO
WHICH WILL KEEP HIGHS IN THE 20S/NIGHTTIME LOWS IN THE TEENS WITH
SOME SINGLE DIGITS POSSIBLE OVER OUR COLDER SECTIONS TO THE EAST.
DESPITE NORTHWEST WINDS A SHOT OF LAKE EFFECT DOES NOT LOOK OVERLY
IMPRESSIVE WITH DRY AIR BEING THE MAIN NEGATING FACTOR. BOTH THE
GFS AND EURO SUGGEST TEMPS WARM UP A BIT SATURDAY...BEFORE ANOTHER
SYSTEM BRINGS US LIGHT SNOW SATURDAY NIGHT INTO SUNDAY...WITH MORE
SEASONABLE AIR.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
630 PM UPDATE...
VFR CONTINUES BUT IT WONT LAST WITH MOISTURE COMING IN FROM THE
WSW AND A COLD FRONT DROPPING SE FROM ONTARIO THIS EVENING. MVFR
CIGS AS CLOSE AS THE LAKE PLAIN AT FULTON AND ROCHESTER. BY 5Z
MVFR CIGS AND VSBYS IN LIGHT SNOW WILL BE ACROSS THE NY SITES.
KAVP WILL REMAIN VFR THROUGH TUESDAY.
SNOW SHOWER COVERAGE WILL PEAK 6 TO 9Z WITH THE FRONT. IFR VSBY
POSSIBLE DURING THIS TIME AT RME AND SYR. AFTER THAT LAKE EFFECT
WILL KICK IN KEEPING THE MVFR GOING INTO TUE MORNING. AROUND 15Z
SOME IMPROVEMENT BUT WITH NW FLOW SYR MAY BE IN MVFR ALL DAY. REST
OF NY SITES MAY BE IN AND OUT OF MVFR DURING THE AFTN. INVERSION
LEVEL...MOISTURE AND DENDRITE LAYERS LOWER DURING THE AFTN SO THE
SNOW SHOWERS WILL DIMINISH IN INTENSITY AND COVERAGE.
SW FLOW AT 5 TO 10 KTS SHIFTING TO W AROUND 5Z...THEN NW AT 10 KTS
LATE TONIGHT THROUGH TUESDAY.
OUTLOOK...
TUE NGT TO WED NGT...OCCASIONAL MVFR/IFR FOR NY TERMINALS IN SNOW
SHOWERS.
THU THROUGH SAT...MAINLY VFR. RESTRICTIONS ARE POSSIBLE AT
KRME/KSYR IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM
NEAR TERM...CMG/PVN/RRM
SHORT TERM...RRM
LONG TERM...HEDEN
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
416 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION ON TUESDAY...BRINGING
AN END TO PRECIPITATION. HIGH PRESSURE WILL MOVE IN FOR
WEDNESDAY...WITH A WEAK DISTURBANCE PASSING NORTH OF THE REGION
THURSDAY AND THURSDAY NIGHT. ANOTHER AREA OF HIGH PRESSURE WILL
MOVE OVER THE OHIO VALLEY ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE PRIMARY FORECAST CONCERN FOR TODAY WILL BE THE CHANCES OF
DRIZZLE / FREEZING DRIZZLE THIS MORNING.
MEASURABLE PRECIPITATION HAS ALL BUT ENDED FOR THE CWA...WITH THE
MAJORITY OF THE FORCING AND DEEP MOISTURE PUSHING OFF TO THE EAST.
HOWEVER...THE RADAR SCREENS HAVE FILLED IN WITH VERY LIGHT ECHOES
(NOT JUST ON KILN...BUT ALSO ON KIND AND THE NEARBY TDWR SITES).
RECENT HRRR RUNS HAVE ALSO DEPICTED PATCHY-LOOKING LIGHT ECHOES IN
SIMULATED REFLECTIVITY. BASED ON SURFACE OBSERVATIONS...THESE
ECHOES ARE AN INDICATION OF A MIXTURE OF FLURRIES AND DRIZZLE. THE
GRIDS WILL THUS TRANSITION QUICKLY THIS MORNING FROM SNOW TO A
FLURRY/DZ OR FLURRY/FZDZ MIX.
ONE OF THE BIGGEST CHALLENGES IN FORECASTING DZ/FZDZ IS CERTAINLY
PRESENTING ITSELF THIS MORNING...AS THERE IS QUITE A BIT OF
UNCERTAINTY IN WHETHER OR NOT THERE IS ENOUGH MOISTURE AT TEMPS
COLDER THAN -10C TO SUPPORT THE PRODUCTION OF ICE CRYSTALS.
MODEL SOUNDINGS SHOW A RAPID DRYING ABOVE 700MB. RAP/NAM RH PLOTS
AT -10C SHOW A RATHER EXTREME DRY PUNCH MOVING ENE OUT OF SOUTHERN
INDIANA...WITH RH VALUES BELOW 5 PERCENT. DESPITE THIS...MANY OF
THE OBSERVATIONS ARE KEEPING -SN AS THE PREVAILING WEATHER TYPE.
BASED ON EYEWITNESS OBSERVATIONS AT NWS ILN...CURRENT
PRECIPITATION IS IN THE FORM OF VERY SMALL CRYSTALS (STILL
ICE...BUT NOT A TYPICAL SNOWFLAKE).
GIVEN THE EXTREMELY WEAK ASCENT...TEMPERATURES VERY CLOSE TO
FREEZING...AND APPARENT MIXING WITH SNOW...NO SIGNIFICANT IMPACTS
FROM FZDZ ARE EXPECTED THIS MORNING.
DESPITE THE DRYING ALOFT...THE LOW LEVEL MOISTURE IS FORECAST TO
REMAIN THICK THROUGH THE DAY...WITH NOWHERE TO GO UNDER AN
INVERSION. ANY EROSION TO THE CLOUD BASE WILL COME LATE IN THE DAY
OR TONIGHT. WITH COLD ADVECTION KICKING IN BEHIND THE SURFACE
FRONT...AND LITTLE TO NOTHING IN THE WAY OF
INSOLATION...TEMPERATURES WILL GO ALMOST NOWHERE TODAY FROM THE
CURRENT VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
MID-LEVEL FLOW WILL REMAIN QUASI-ZONAL OVER THE OHIO VALLEY
THROUGH THE END OF THE WEEK. AT THE SURFACE...HIGH PRESSURE WILL
BEGIN NUDGING INTO THE OHIO VALLEY FROM THE SOUTHWEST TONIGHT.
THIS NARROW RIDGE WILL BE SHUNTED A BIT TO THE SOUTHEAST AS A
STACKED TROUGH (AND EVENTUAL SURFACE LOW) PASSES THROUGH THE GREAT
LAKES ON THURSDAY. AFTER THE TROUGH AXIS CLEARS THE OHIO VALLEY
THURSDAY NIGHT...A MUCH STRONGER AND LARGER HIGH WILL BEGIN TO
ESTABLISH ITSELF ON FRIDAY.
WITH THE CHILLY STARTING POINT AND GRADUALLY CLEARING SKIES...NOT
TO MENTION THE SNOW PACK OVER THE REGION...SINGLE DIGIT TEMPS
ARE BEING FORECAST FOR THE NORTHWESTERN CWA TONIGHT. ON
WEDNESDAY...VERY LITTLE MIXING WILL OCCUR UNDER AN INVERSION...AND
THE AXIS OF COLDEST 925MB TEMPS WILL ALSO BE PASSING THROUGH THE
CWA. THROUGH BOTH OF THESE PERIODS...THE FORECAST IS GENERALLY
LOWER THAN MODEL GUIDANCE. THE EXCEPTION TO THIS IS THE ECMWF FOR
LOWS TONIGHT...WHICH IS GOING AS LOW AS 1 DEGREE IN DARKE COUNTY.
THE COLD PATTERN WILL CONTINUE THROUGH THE WEEK...WITH ANOTHER
SHOT OF COLD ADVECTION KICKING IN WITH THE SHORTWAVE ON THURSDAY.
A SLIGHT CHANCE OF LIGHT SNOW HAS BEEN KEPT IN THE FORECAST FOR
THURSDAY EVENING...GENERALLY FOR AREAS NORTH OF I-70. AN ARGUMENT
COULD BE MADE THAT ONLY FLURRIES WILL BE EXPERIENCED THIS FAR
SOUTH...SO THIS IS FAR FROM A CERTAINTY OR ANYTHING THAT WILL
CAUSE MUCH OF AN IMPACT.
LITTLE CHANGE IS EXPECTED FOR FRIDAY...WITH THE CWA AT THE
NORTHEAST PERIPHERY OF THE SURFACE HIGH...AND STILL FAR AWAY FROM
ANY LEGITIMATE WARM ADVECTION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THE 12Z ECMWF...GFS AND CMC ARE ALL IN DECENT AGREEMENT WITH SHORT
WAVE ENERGY DROPPING DOWN ACROSS THE LOWER GREAT LAKES THURSDAY
AFTERNOON INTO FRIDAY MORNING. THE BEST FORCING ASSOCIATED WITH THIS
WILL REMAIN OFF TO OUR NORTH AND EAST...BUT THINK A FEW FLURRIES OR
LIGHT SNOW SHOWERS WILL BE POSSIBLE AT LEAST ACROSS OUR NORTHEASTERN
AREAS...PRIMARILY THURSDAY NIGHT. TEMPERATURES WILL REMAIN
SEASONABLY COLD TO START THE LONG TERM PERIOD. WITH A LITTLE BIT OF
REINFORCING COLD AIR BEHIND THE SHORT WAVE...WILL GO A COUPLE OF
DEGREES COOLER FOR HIGHS FRIDAY COMPARED TO THURSDAY.
WE WILL TRANSITION INTO MORE OF A WESTERLY FLOW PATTERN THROUGH THE
WEEKEND...ALLOWING FOR A MODERATION IN TEMPERATURES SATURDAY THROUGH
MONDAY. BY THE END OF THE PERIOD...EXPECT HIGHS TO BE NEAR OR EVEN A
LITTLE ABOVE NORMAL FOR THIS TIME OF YEAR. THE GFS AND ECMWF ARE
BOTH SHOWING A FAIRLY PROGRESSIVE SHORT WAVE WORKING ACROSS THE
REGION SATURDAY NIGHT INTO SUNDAY. WE MAY EVENTUALLY NEED SOME LOW
POPS WITH THIS FEATURE...BUT MOISTURE APPEARS LIMITED SO WILL
MAINTAIN A DRY FORECAST AT THIS POINT.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
A COLD FRONT WILL MOVE SLOWLY SOUTHEAST ACROSS THE TAF SITES THIS
MORNING. A QUICK INJECTION OF WAA ALONG AND AHEAD OF THE FRONT
WILL BRING A BRIEF PERIOD OF SNOW EARLY THIS MORNING...ENDING
BETWEEN 08Z AND 10Z. THE SNOW WILL BRING IFR CIGS AND VSBYS.
THEREAFTER...VSBYS WILL LIFT TO MVFR AND CIGS WILL REMAIN IFR
THROUGH MUCH OF THE MORNING. THERE IS A SMALL CHANCE THAT AS THE
MAIN PCPN COMES TO AN END THAT THERE COULD BE A LITTLE FREEZING
DRIZZLE. LATEST MODEL GUIDANCE...HOWEVER...DOES NOT SHOW MUCH LIFT
IN THE LOW LEVELS...SO WILL NOT PLACE IN THE TAFS.
FOR THIS AFTERNOON...DRIER AIR WILL BRING VSBYS BACK TO VFR...BUT
LOW LEVEL MOISTURE WILL REMAIN WITH CIGS MVFR...BUT LIKELY
REMAINING BELOW 2000 FEET. HIGH PRESSURE WILL BEGIN TO BUILD INTO
THE REGION TONIGHT AND ESTABLISH ITSELF OVER THE REGION ON
TUESDAY. THIS WILL ALLOW LOW LEVEL MOISTURE TO EVENTUALLY
SCOUR OUT/ERODE OVER THE AREA.
OUTLOOK...MVFR CEILINGS POSSIBLE THURSDAY INTO FRIDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...JGL
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS NORMAN OK
1111 PM CST MON DEC 31 2012
.AVIATION...
06Z TAFS... CEILINGS WILL BE VARIABLE TONIGHT ACROSS THE AREA.
SOME VISIBILITIES WILL ALSO BE REDUCED BUT MAYBE NOT AS LOW AS
EARLIER THIS EVENING. FZDZ WILL STILL BE POSSIBLE INTO TUESDAY
MORNING... WHILE SOME SNOW FLURRIES MAY ALSO OCCUR IN A FEW
LOCATIONS. CONDITIONS WILL IMPROVE TUESDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 1012 PM CST MON DEC 31 2012/
DISCUSSION...
NO BIG CHANGES TO FORECAST THIS EVENING. COLDER AIR CONTINUES TO
STEADILY FILTER INTO THE REGION WITH SURFACE FREEZING LINE NOW
FROM ABOUT MIDFORD TO ALTUS TO CROWELL TX. SOME WEAK ECHOES
PERSIST NEAR THE KANSAS BORDER WITH LIGHT SNOW OR DRIZZLE/FRSG
DRIZZLE. THUS WILL LEAVE WINTER WEATHER ADVY IN PLACE AS IS.
ALTHOUGH DEEPER MOISTURE HAS BEEN SHUNTED EWD WITH LEAD WAVE
EARLIER TODAY...MODELS SHOW INCREASING LIFT AND MID LEVEL
MOISTENING WITH IMPULSE LIFTING NEWD THROUGH W TX. HRRR THE MOST
BULLISH WITH PRECIP POTENTIAL ALTHOUGH ANYTHING THAT MAKES IT TO
THE GROUND WOULD BE VERY LIGHT. THUS WILL CONTINUE WITH MENTION
OF DRIZZLE/FREEZING DRIZZLE OVERNIGHT. NO CHANGES BEYOND THE FIRST
PD.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 30 33 23 40 / 20 10 10 10
HOBART OK 24 32 20 40 / 10 0 0 0
WICHITA FALLS TX 31 39 23 40 / 10 10 10 10
GAGE OK 19 29 16 38 / 10 10 0 0
PONCA CITY OK 26 32 18 42 / 20 10 10 10
DURANT OK 36 43 27 42 / 10 10 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR OKZ006>008-
012-013.
WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR OKZ004-005-
009-010.
TX...NONE.
&&
$$
02/25/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
1012 PM CST MON DEC 31 2012
.DISCUSSION...
NO BIG CHANGES TO FORECAST THIS EVENING. COLDER AIR CONTINUES TO
STEADILY FILTER INTO THE REGION WITH SURFACE FREEZING LINE NOW
FROM ABOUT MIDFORD TO ALTUS TO CROWELL TX. SOME WEAK ECHOES
PERSIST NEAR THE KANSAS BORDER WITH LIGHT SNOW OR DRIZZLE/FRSG
DRIZZLE. THUS WILL LEAVE WINTER WEATHER ADVY IN PLACE AS IS.
ALTHOUGH DEEPER MOISTURE HAS BEEN SHUNTED EWD WITH LEAD WAVE
EARLIER TODAY...MODELS SHOW INCREASING LIFT AND MID LEVEL
MOISTENING WITH IMPULSE LIFTING NEWD THROUGH W TX. HRRR THE MOST
BULLISH WITH PRECIP POTENTIAL ALTHOUGH ANYTHING THAT MAKES IT TO
THE GROUND WOULD BE VERY LIGHT. THUS WILL CONTINUE WITH MENTION
OF DRIZZLE/FREEZING DRIZZLE OVERNIGHT. NO CHANGES BEYOND THE FIRST
PD.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 40 30 33 23 / 30 20 10 10
HOBART OK 42 24 32 20 / 20 10 0 0
WICHITA FALLS TX 48 31 39 23 / 20 10 10 10
GAGE OK 36 19 29 16 / 40 10 10 0
PONCA CITY OK 36 26 32 18 / 70 20 10 10
DURANT OK 42 36 43 27 / 50 10 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR OKZ006>008-
012-013.
WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR OKZ004-005-
009-010.
TX...NONE.
&&
$$
02/25
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1051 PM CST MON DEC 31 2012
.DISCUSSION.../ISSUED AT 1014 PM CST/
CURRENTLY SEEING AN AREA OF STRATUS MOVING EAST ACROSS THE CWA. HAVE
MADE UPDATES TO SKY COVER AND TEMPERATURES THROUGH TONIGHT. LOOKS
LIKE THIS STRATUS WILL CONTINUE TO MOVE EAST...COVERING THE ENTIRE
CWA BY 09Z. WHERE STRATUS IS CURRENTLY...LOWS HAVE LIKELY ALREADY
BEEN REACHED. PORTIONS OF SOUTHWEST MINNESOTA AND NORTHWEST IOWA
HAVE A COUPLE MORE HOURS TO DROP...BEFORE STRATUS MOVES IN AND
TEMPERATURES GO UP. RAP HAS A DECENT HANDLE ON STRATUS EVOLUTION.
THUS HAVE FOLLOWED CLOSER TO IT AND INCREASED CLOUDS THROUGH
TOMORROW. DONT SEE MUCH REASON WHY THE STRATUS WILL
DISSIPATE...SEEMS MORE LIKELY IT WILL CONTINUE TO MOVE EAST AS THE
BOUNDARY LAYER FLOW TURNS WESTERLY AND CLEAR FROM WEST TO EAST
TOMORROW. CLEARING AROUND 12Z IN OUR WEST...AFTER 18Z IN THE
INTERSTATE 29 CORRIDOR...AND NOT EXITING OUR EAST UNTIL AFTER 0Z.
WOULD NOT BE SURPRISED IF HIGHS TOMORROW END UP A FEW DEGREES BELOW
FORECAST GIVEN THE CLOUDS....BUT WILL LEAVE THEM AS IS FOR NOW...AS
WITH THE WARMER START WE STILL MIGHT BE ABLE TO GET CLOSE TO THE
FORECAST HIGHS. /CHENARD
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
SKY CONDITIONS HAVE BECOME LESS MUDDLED SINCE THE PREVIOUS TAF
FORECAST. AT THIS TIME...A LOT OF MVFR STRATUS IS MOVING EASTWARD
ACROSS OUR FORECAST AREA...AND WILL EVENTUALLY MOVE THROUGH ALL OF
SOUTHWEST MINNESOTA AND MUCH OF NORTHWEST IOWA BY LATE TONIGHT. SO
THE MAIN QUESTION NOW IS WHEN WILL THE MVFR CONDITIONS ABATE ON
TUESDAY. LOW LEVEL WINDS FROM THE SURFACE TO THE BOUNDARY LAYER WILL
BECOME SOUTHERLY AS THE REST OF THE NIGHT PROGRESSES. HOWEVER THERE
CERTAINLY IS A SUBTLE TROUGH AXIS CURRENTLY MOVING THROUGH WESTERN
AND CENTRAL SD. THEREFORE BOUNDARY LAYER WINDS WILL BECOME WESTERLY
AT CHAMBERLAIN SD BY ABOUT 11Z...AND THEN MOVE EASTWARD FROM THERE
ALBEIT WEAKENING AND THUS KEEPING THE LOW LEVEL WIND DIRECTION FROM
THE SOUTHWEST FROM THE JAMES VALLEY AND POINTS EASTWARD. WITH LOW
LEVEL WINDS FROM THE SOUTHWEST INSTEAD OF DUE WEST...THIS MAY SLOW
THE PROGRESSION OF THE EASTWARD MOVING CLEARING LINE ON TUESDAY.
HOWEVER THERE SHOULD BE ENOUGH PUSH...EVEN WITH LIGHT WINDS...TO
ADVANCE THE CLEARING LINE TO THE I 29 CORRIDOR BY MIDDAY TUESDAY...
AND INTO SOUTHWEST MN AND NORTHWEST IA THROUGH TUESDAY AFTERNOON. SO
CURRENT THINKING IS FOR THE KHON TAF SITE TO GO VFR IN THE MID TO
LATE MORNING...AND THE KFSD AND KSUX TAF SITES TO GO VFR BY MIDDAY.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 255 PM CST/
FOCUS TONIGHT WILL BE ON STRATUS IN THE WESTERN CWA AND WEATHER OR
NOT THAT WILL TRANSLATE EAST. THE REASON THIS IS SO IMPORTANT IS IT
WILL LIKELY HAVE A 10 TO 15 DEGREE AFFECT ON TEMPERATURES...WITH
AREAS STAYING OUT OF THE STRATUS FALLING TO AROUND 10 BELOW WHILE
THOSE AREAS UNDER THE STRATUS SHOULD DROP TO ABOUT 5 ABOVE OR SO.
DRY ARCTIC AIR INTRUDING FROM THE NORTHEAST SHOULD HOLD THE STRATUS
AT BAY THROUGH MID EVENING BUT HAVE THE FEELING THAT IT WILL WORK
EASTWARD ACROSS INTERSTATE 29 INTO NORTHWEST IOWA. THE AREA WITH THE
BEST CHANCE TO REMAIN IN THE CLEAR WILL BE ALONG AND EAST OF THE
BUFFALO RIDGE...SO WILL KEEP LOWS AROUND 10 BELOW IN THESE
LOCATIONS. WILL THEN TRANSITION TO LOWS OF ABOUT 5 TO 10 ABOVE ZERO
IN CENTRAL SOUTH DAKOTA WHERE CLOUDS ARE IN PLACE AND A LIGHT SOUTH
TO SOUTHWEST WIND SHOULD DEVELOP LATE TONIGHT. THE INTERSTATE 29
CORRIDOR THE TOUGHEST CALL BECAUSE IF STRATUS COMES IN AROUND SUNSET
LOWS WILL LIKELY BE 10 DEGREES HIGHER THAN FORECAST. ALSO NEED TO
WATCH THE SNOW TO THE SOUTH AS A FEW FLURRIES COULD WORK NORTH
TOWARDS SIOUX CITY AND STORM LAKE THIS EVENING BUT FOR NOW BELIEVE
THAT THE DRY ARCTIC AIR IN THE LOWER LEVELS WILL KEEP THE FLAKES TO
THE SOUTH.
EXPECT THE STRATUS TO LIFT AND PARTLY TO MOSTLY SUNNY SKIES TO
DEVELOP ON TUESDAY AS A WEST TO SOUTHWEST WIND BRINGS IN MILDER
READINGS. RAISED HIGHS A BIT AND KEPT TEMPERATURES WARMER THAN
GUIDANCE BY LATE IN THE DAY AS CONDITIONS SHOULD REMAIN MIXED INTO
THE EVENING. EXPECT HIGHS NEAR 20 IN THE EAST AND NEAR 30 IN THE
WEST. /08
A WEAK AND DISORGANIZED WAVE WILL MOVE ACROSS THE AREA ON WEDNESDAY
WHICH WILL BE FOLLOWED BY ANOTHER BRIEF SHOT OF COLD AIR. THE UPPER
WAVE WAVE WILL BEGIN TO APPROACH ON TUESDAY NIGHT WITH AN INCREASE
IN BOTH CLOUDS AND WESTERLY WINDS. WITH WEST WINDS INCREASING
THROUGH THE NIGHT...EXPECT THAT MOST PLACES WILL REACH LOWS IN THE
EVENING WITH RISING TEMPERATURES OVERNIGHT. SOME LIGHT SNOW MAY MOVE
IN LATE IN THE NIGHT WEST OF THE JAMES RIVER.
THE UPPER WAVE MOVES ACROSS ON WEDNESDAY. THERE IS LITTLE TO NO
FRONTOGENESIS OR EVEN WARM ADVECTION WITH THIS SYSTEM...IT RELIES
ENTIRELY ON THE UPPER LEVEL WAVE. ALL MODELS SHOW THAT THE DYNAMICS
REALLY BEGIN TO WEAKEN AND SPLIT WITH SOME ENERGY DIVING INTO
NEBRASKA AND THE REST STAYING CLOSER TO I94. AS A RESULT...WHILE WE
EXPECT TO SEE FLURRIES WITH THIS SYSTEM BETWEEN WEDNESDAY AND
WEDNESDAY NIGHT...THE PROBABILITY OF MEASURABLE SNOW REMAINS
LOW...50 PERCENT OR LESS. AND FOR LOCATIONS THAT SEE MEASURABLE
SNOWFALL...IT SHOULD BE LESS THAN AN INCH AND LIKELY LESS THAN A
HALF INCH. THE BEST CHANCE FOR MEASURABLE SNOW WILL BE WEDNESDAY
AFTERNOON...ALTHOUGH FLURRIES ARE LIKELY TO CONTINUE INTO WEDNESDAY
NIGHT. HIGHS WEDNESDAY WILL BE IN THE 20S. WITH THE COLD AIR MOVING
IN ON NW WINDS...LOW WEDNESDAY NIGHT WILL BE IN THE SINGLE DIGITS
ABOVE ZERO.
THURSDAY LOOKS TO BE BELOW NORMAL AS COLD AIR MOVES IN EAST OF THE
JAMES RIVER. THIS COLD AIR WILL NOT LAST LONG AND WARMING WILL
ALREADY MOVE INTO AREAS WEST OF THE JAMES BY THURSDAY AFTERNOON.
EVEN WITH WEAK EARLY JANUARY SUN...HIGHS WILL STRUGGLE TO GET ABOVE
10 DEGREES EAST OF THE JAMES...BUT SHOULD APPROACH 20 IN SOUTH
CENTRAL SD. THURSDAY NIGHT COULD BE A REPEAT OF TUESDAY NIGHT WITH A
QUICK DROP FOR 5 TO 10 DEGREES AND THEN RISING TEMPERATURES AS
WESTERLY WINDS PICK UP.
FOR FRIDAY THROUGH MONDAY...IT IS LOOKING LIKE A FAIRLY SIGNIFICANT
WARMING TREND WITH NO PRECIPITATION. THERE IS VERY LITTLE DIFFERENCE
BETWEEN THE ECMWF...GFS AND THE GFS ENSEMBLE. ALL AGREE THAT A LONG
WAVE RIDGE WILL SET UP OVER THE CWA. WHILE A WAVE WILL DROP
SOUTHEAST IN THE NW FLOW ON FRIDAY NIGHT AND SATURDAY...IT WILL
BRING ONLY A BRIEF PERIOD OF COOLER AIR FOLLOWED BY VERY MILD AIR BY
SUNDAY. THE ONLY QUESTION REALLY IS HOW MUCH SNOW COVER INHIBITS
MIXING AND WARMING DURING THE DAY. THE SNOWPACK...WHILE FROM 4 TO
10 INCHES...IS FAIRLY DRY AND WITH A LONG ENOUGH WARM PERIOD COULD
BE SIGNIFICANTLY REDUCED BY MONDAY. FOR NOW STAYED CONSERVATIVE WITH
HIGHS FRIDAY AND SATURDAY IN THE 20S AND 30S. HAVE THE WARMEST DAY
ON SUNDAY WITH HIGHS IN THE 30S AND 40S AND SIMILAR TEMPERATURES
FORECAST FOR MONDAY. IF SNOWCOVER DISAPPEARS FASTER THAN
EXPECTED...HIGHS BY SUNDAY AND MONDAY COULD BE ANOTHER 5 TO 10
DEGREES WARMER./SCHUMACHER
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY
FOR IAZ002-003-014-022.
MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY
FOR MNZ071-072-080-081-089-090.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1014 PM CST MON DEC 31 2012
.DISCUSSION.../ISSUED AT 1014 PM CST/
CURRENTLY SEEING AN AREA OF STRATUS MOVING EAST ACROSS THE CWA. HAVE
MADE UPDATES TO SKY COVER AND TEMPERATURES THROUGH TONIGHT. LOOKS
LIKE THIS STRATUS WILL CONTINUE TO MOVE EAST...COVERING THE ENTIRE
CWA BY 09Z. WHERE STRATUS IS CURRENTLY...LOWS HAVE LIKELY ALREADY
BEEN REACHED. PORTIONS OF SOUTHWEST MINNESOTA AND NORTHWEST IOWA
HAVE A COUPLE MORE HOURS TO DROP...BEFORE STRATUS MOVES IN AND
TEMPERATURES GO UP. RAP HAS A DECENT HANDLE ON STRATUS EVOLUTION.
THUS HAVE FOLLOWED CLOSER TO IT AND INCREASED CLOUDS THROUGH
TOMORROW. DONT SEE MUCH REASON WHY THE STRATUS WILL
DISSIPATE...SEEMS MORE LIKELY IT WILL CONTINUE TO MOVE EAST AS THE
BOUNDARY LAYER FLOW TURNS WESTERLY AND CLEAR FROM WEST TO EAST
TOMORROW. CLEARING AROUND 12Z IN OUR WEST...AFTER 18Z IN THE
INTERSTATE 29 CORRIDOR...AND NOT EXITING OUR EAST UNTIL AFTER 0Z.
WOULD NOT BE SURPRISED IF HIGHS TOMORROW END UP A FEW DEGREES BELOW
FORECAST GIVEN THE CLOUDS....BUT WILL LEAVE THEM AS IS FOR NOW...AS
WITH THE WARMER START WE STILL MIGHT BE ABLE TO GET CLOSE TO THE
FORECAST HIGHS. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 255 PM CST/
FOCUS TONIGHT WILL BE ON STRATUS IN THE WESTERN CWA AND WEATHER OR
NOT THAT WILL TRANSLATE EAST. THE REASON THIS IS SO IMPORTANT IS IT
WILL LIKELY HAVE A 10 TO 15 DEGREE AFFECT ON TEMPERATURES...WITH
AREAS STAYING OUT OF THE STRATUS FALLING TO AROUND 10 BELOW WHILE
THOSE AREAS UNDER THE STRATUS SHOULD DROP TO ABOUT 5 ABOVE OR SO.
DRY ARCTIC AIR INTRUDING FROM THE NORTHEAST SHOULD HOLD THE STRATUS
AT BAY THROUGH MID EVENING BUT HAVE THE FEELING THAT IT WILL WORK
EASTWARD ACROSS INTERSTATE 29 INTO NORTHWEST IOWA. THE AREA WITH THE
BEST CHANCE TO REMAIN IN THE CLEAR WILL BE ALONG AND EAST OF THE
BUFFALO RIDGE...SO WILL KEEP LOWS AROUND 10 BELOW IN THESE
LOCATIONS. WILL THEN TRANSITION TO LOWS OF ABOUT 5 TO 10 ABOVE ZERO
IN CENTRAL SOUTH DAKOTA WHERE CLOUDS ARE IN PLACE AND A LIGHT SOUTH
TO SOUTHWEST WIND SHOULD DEVELOP LATE TONIGHT. THE INTERSTATE 29
CORRIDOR THE TOUGHEST CALL BECAUSE IF STRATUS COMES IN AROUND SUNSET
LOWS WILL LIKELY BE 10 DEGREES HIGHER THAN FORECAST. ALSO NEED TO
WATCH THE SNOW TO THE SOUTH AS A FEW FLURRIES COULD WORK NORTH
TOWARDS SIOUX CITY AND STORM LAKE THIS EVENING BUT FOR NOW BELIEVE
THAT THE DRY ARCTIC AIR IN THE LOWER LEVELS WILL KEEP THE FLAKES TO
THE SOUTH.
EXPECT THE STRATUS TO LIFT AND PARTLY TO MOSTLY SUNNY SKIES TO
DEVELOP ON TUESDAY AS A WEST TO SOUTHWEST WIND BRINGS IN MILDER
READINGS. RAISED HIGHS A BIT AND KEPT TEMPERATURES WARMER THAN
GUIDANCE BY LATE IN THE DAY AS CONDITIONS SHOULD REMAIN MIXED INTO
THE EVENING. EXPECT HIGHS NEAR 20 IN THE EAST AND NEAR 30 IN THE
WEST. /08
A WEAK AND DISORGANIZED WAVE WILL MOVE ACROSS THE AREA ON WEDNESDAY
WHICH WILL BE FOLLOWED BY ANOTHER BRIEF SHOT OF COLD AIR. THE UPPER
WAVE WAVE WILL BEGIN TO APPROACH ON TUESDAY NIGHT WITH AN INCREASE
IN BOTH CLOUDS AND WESTERLY WINDS. WITH WEST WINDS INCREASING
THROUGH THE NIGHT...EXPECT THAT MOST PLACES WILL REACH LOWS IN THE
EVENING WITH RISING TEMPERATURES OVERNIGHT. SOME LIGHT SNOW MAY MOVE
IN LATE IN THE NIGHT WEST OF THE JAMES RIVER.
THE UPPER WAVE MOVES ACROSS ON WEDNESDAY. THERE IS LITTLE TO NO
FRONTOGENESIS OR EVEN WARM ADVECTION WITH THIS SYSTEM...IT RELIES
ENTIRELY ON THE UPPER LEVEL WAVE. ALL MODELS SHOW THAT THE DYNAMICS
REALLY BEGIN TO WEAKEN AND SPLIT WITH SOME ENERGY DIVING INTO
NEBRASKA AND THE REST STAYING CLOSER TO I94. AS A RESULT...WHILE WE
EXPECT TO SEE FLURRIES WITH THIS SYSTEM BETWEEN WEDNESDAY AND
WEDNESDAY NIGHT...THE PROBABILITY OF MEASURABLE SNOW REMAINS
LOW...50 PERCENT OR LESS. AND FOR LOCATIONS THAT SEE MEASURABLE
SNOWFALL...IT SHOULD BE LESS THAN AN INCH AND LIKELY LESS THAN A
HALF INCH. THE BEST CHANCE FOR MEASURABLE SNOW WILL BE WEDNESDAY
AFTERNOON...ALTHOUGH FLURRIES ARE LIKELY TO CONTINUE INTO WEDNESDAY
NIGHT. HIGHS WEDNESDAY WILL BE IN THE 20S. WITH THE COLD AIR MOVING
IN ON NW WINDS...LOW WEDNESDAY NIGHT WILL BE IN THE SINGLE DIGITS
ABOVE ZERO.
THURSDAY LOOKS TO BE BELOW NORMAL AS COLD AIR MOVES IN EAST OF THE
JAMES RIVER. THIS COLD AIR WILL NOT LAST LONG AND WARMING WILL
ALREADY MOVE INTO AREAS WEST OF THE JAMES BY THURSDAY AFTERNOON.
EVEN WITH WEAK EARLY JANUARY SUN...HIGHS WILL STRUGGLE TO GET ABOVE
10 DEGREES EAST OF THE JAMES...BUT SHOULD APPROACH 20 IN SOUTH
CENTRAL SD. THURSDAY NIGHT COULD BE A REPEAT OF TUESDAY NIGHT WITH A
QUICK DROP FOR 5 TO 10 DEGREES AND THEN RISING TEMPERATURES AS
WESTERLY WINDS PICK UP.
FOR FRIDAY THROUGH MONDAY...IT IS LOOKING LIKE A FAIRLY SIGNIFICANT
WARMING TREND WITH NO PRECIPITATION. THERE IS VERY LITTLE DIFFERENCE
BETWEEN THE ECMWF...GFS AND THE GFS ENSEMBLE. ALL AGREE THAT A LONG
WAVE RIDGE WILL SET UP OVER THE CWA. WHILE A WAVE WILL DROP
SOUTHEAST IN THE NW FLOW ON FRIDAY NIGHT AND SATURDAY...IT WILL
BRING ONLY A BRIEF PERIOD OF COOLER AIR FOLLOWED BY VERY MILD AIR BY
SUNDAY. THE ONLY QUESTION REALLY IS HOW MUCH SNOW COVER INHIBITS
MIXING AND WARMING DURING THE DAY. THE SNOWPACK...WHILE FROM 4 TO
10 INCHES...IS FAIRLY DRY AND WITH A LONG ENOUGH WARM PERIOD COULD
BE SIGNIFICANTLY REDUCED BY MONDAY. FOR NOW STAYED CONSERVATIVE WITH
HIGHS FRIDAY AND SATURDAY IN THE 20S AND 30S. HAVE THE WARMEST DAY
ON SUNDAY WITH HIGHS IN THE 30S AND 40S AND SIMILAR TEMPERATURES
FORECAST FOR MONDAY. IF SNOWCOVER DISAPPEARS FASTER THAN
EXPECTED...HIGHS BY SUNDAY AND MONDAY COULD BE ANOTHER 5 TO 10
DEGREES WARMER./SCHUMACHER
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
CONDITIONS SHOULD REMAIN VFR FOR MANY AREAS EAST OF THE I 29
CORRIDOR FOR TONIGHT AND EARLY TUESDAY. HOWEVER ALONG AND WEST OF I
29...CONDITIONS BECOME MORE PROBLEMATIC. THERE ARE GENERALLY FOUR
LAYERS OF CLOUDS. ONE IS AROUND 8000 FEET AGL EXTENDING THROUGH MUCH
OF EAST CENTRAL AND SOUTHEAST SD. ANOTHER IS NEAR 3000 FEET AGL IN
EAST CENTRAL SD...ARCHING SOUTHWARD TO JUST NORTH OF KFSD. A THIRD
DECK IS CURRENTLY NEAR 2200 FEET AGL IN THE MIDDLE PORTIONS OF THE
JAMES RIVER VALLEY...WHILE THE LAST DECK OF AROUND 1500 FEET IS
EVIDENT IN SOUTH CENTRAL SD. FURTHERMORE...THE IR VIS/FOG CURVE SHOW
THAT KHON AND KMHE ARE ACTUALLY ON THE VERY EDGE OF THE 2200 FOOT
DECK WITH MID LEVEL CLOUDS IN BETWEEN THE TWO SITES. WINDS OFF THE
SURFACE ARE THE KEY...AND MAINLY FOLLOWED THE RUC13 FOR GUIDANCE.
THEREFORE THE KFSD AND KHON TAF SITES SHOULD SEE MVFR CONDITIONS FOR
MUCH OF THE NIGHT AND TUESDAY MORNING...BUT AT TIMES WILL PROBABLY
BE VFR NEAR 8000 FEET DEPENDING ON EXACT MOVEMENT OF THE MVFR DECK.
KSUX MAY BE IN A SWEET SPOT...TOO FAR SOUTH TO BE IMPACTED BY THE
SOUTH DAKOTA STRATUS...AND TOO FAR NORTH TO BE IMPACTED BY THE UPPER
LOW TO THE SOUTH. THAT SAID...WINDS OFF THE SURFACE IN THE BOUNDARY
LAYER SWITCH TO THE SOUTHWEST TUESDAY MORNING...SO AM CONCERNED THAT
SOME STRATUS IN THE CENTRAL PLAINS WILL MOVE INTO KSUX AS TUESDAY
MORNING PROGRESSES. FURTHERMORE...WITH THE AFOREMENTIONED WINDS OFF
THE SURFACE ALSO OF A SOUTHWEST DIRECTION FOR THE KFSD AND KHON TAF
SITES...AM NOT OVERLY CONFIDENT THAT THEY WILL SCATTER OUT IN THE
AFTERNOON ON TUESDAY...AGAIN DUE TO THE ABUNDANT STRATUS IN THE
CENTRAL PLAINS. /MJF
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY
FOR IAZ002-003-014-022.
MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY
FOR MNZ071-072-080-081-089-090.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
458 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM NEW YORK TO MISSOURI EARLY THIS
MORNING. THIS FRONT WILL MOVE SOUTHEAST THROUGH THE REGION THIS
AFTERNOON AND TONIGHT. LOW PRESSURE WILL CROSS THROUGH THE GULF
COAST REGION TODAY AND TONIGHT AND OFF THE SOUTHEAST COAST BY
WEDNESDAY MORNING. A LARGE HIGH PRESSURE SYSTEM WILL COVER MUCH OF
THE EASTERN UNITED STATES ON THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 435 AM EST TUESDAY...
AREA RADARS WERE SHOWING EASTERN EDGE OF LARGE BAND OF
PRECIPITATION OVER THE WESTERN COUNTY WARNING AREA...ALTHOUGH AT
THE SURFACE NOT ALL OF THIS WAS REACHING THE GROUND. SURFACE DEW
POINTS REMAINED WELL BE LOW CURRENT TEMPERATURES BUT WERE RISING
SLOWLY THROUGH THE 20S.
HAVE SLOWED DOWN ARRIVAL OF MORE WIDESPREAD PRECIPITATION. MODELS
KEEP BEST PROBABILITY OF PRECIPITATION IN THE WESTERN AND SOUTHERN
COUNTY WARNING AREA. ANY WINTER PRECIPITATION LOOKS TO BE CONFINED
FROM SOUTHEAST WEST VIRGINIA INTO BATH AND ROCKBRIDGE COUNTIES.
LARGE OF BAND OF RAIN EXTENDED FROM SOUTHERN WEST VIRGINIA TO
NORTHERN LOUISIANA ALONG A BAROCLINIC ZONE AND ELONGATED AXIS OF
VORTICITY. BEST LIFT SHIFTS SOUTH OF THE FORECAST AREA LATE
TONIGHT. AS WINDS COME AROUND TO THE NORTHWEST AT THE SURFACE
AND LOW LEVEL WITH THE PASSAGE OF A COLD FRONT TONIGHT...COLDER
AIR MOVES INTO THE REGION AND WILL CHANGE MUCH OF WHAT IS LEFT OF
THE PRECIPITATION TO SNOW. BUFKIT WAS SHOWING ENOUGH HIGH CLOUDS
FOR ADEQUATE SEEDER- FEEDER PROCESS TO MAINTAIN SNOW IN THE
MOUNTAINS AS THE PRECIPITATION ENDS.
STAYED WITH COOLER GRIDDED LAMP GUIDANCE FOR TODAY WITH ALL THE
CLOUDS AND PRECIPITATION. USED A BLEND OF GUIDANCE FOR LOWS
TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 330 AM EST TUESDAY...
EARLY WEDNESDAY MORNING...LINGERING LIGHT PRECIPITATION IS EXPECTED
ON THE TAIL END OF THE EXITING SYSTEM. GUIDANCE IS SUGGESTING
LIMITED...IF ANY SATURATED LAYERS IN THE PREFERRED DENDRITIC
ZONE...SO FREEZING DRIZZLE IS POSSIBLE. WILL ONLY HAVE LIMITED
COVERAGE ACROSS THE NORTHERN MOUNTAINS OF NORTH CAROLINA FOR A FEW
HOURS AFTER SUNRISE.
HIGH PRESSURE BUILDS OVER THE UPPER OHIO VALLEY BY WEDNESDAY EVENING
AND SETTLES OF THE MID-ATLANTIC STATES BY THURSDAY MORNING. THIS
WILL BRING DRY WEATHER TO MOST OF THE REGION. MODEL GUIDANCE HAS
BEEN HINTING AT THE NORTHERN EXTENT OF A PRECIPITATION ASSOCIATED
WITH A LOW MOVING ALONG THE GULF COAST TO REACH THE FAR SOUTHERN
PORTION OF THE FORECAST AREA LATE WEDNESDAY NIGHT INTO THURSDAY.
COMPARED TO 24 HOURS AGO...THERE HAS BEEN A NOTABLE SHIFT SOUTH IN
MULTIPLES MODELS IN THE EXTENT OF THIS PRECIPITATION SO THAT NO OR
VERY LITTLE ASSOCIATED PRECIPITATION REACHES THE AREA. GIVEN THE
GOOD CONSENSUS OF THE MODELS...HAVE ADJUSTED OUR FORECAST
ACCORDINGLY. WILL NOW ONLY HAVE A SLIGHT CHANCE OF LIGHT RAIN OR
LIGHT SNOW IN THE NORTHERN MOUNTAIN AND FOOTHILLS OF NORTH CAROLINA
DURING THIS TIME FRAME.
THURSDAY NIGHT INTO FRIDAY OUR ATTENTION TURNS TOWARD THE GREAT
LAKES AS A CLIPPER SYSTEM ENTERS INTO THE OHIO VALLEY. LIMITED
MOISTURE WILL BE ASSOCIATED WITH IT...BUT WE EXPECT ENOUGH
INSTABILITY FOR THE DEVELOPMENT OF SOME UPSLOPE SNOW SHOWERS IN THE
PREFERRED UPSLOPE AREAS OF SOUTHEAST WEST VIRGINIA AND NEIGHBORING
SECTIONS OF SOUTHWEST VIRGINIA. OUR PREVIOUS FORECAST INCLUDED
THESE...AND WE WILL CONTINUE TO ADVERTISE THEM IN THIS ISSUANCE.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 230 PM EST MONDAY...
HIGH PRESSURE WILL BUILD EAST OUT OF THE CENTRAL U.S. ON FRIDAY.
THE 1030 MB SURFACE HIGH WILL REMAIN ACROSS THE REGION DURING THE
WEEKEND. WITH THE HIGH CENTER SETTLING SOUTH AND A SOUTHWEST FLOW
WILL CONTINUE TO MODERATE TEMPERATURES EARLY NEXT WEEK. ANOTHER
STORM MAY SPREAD MOISTURE INTO OUR REGION OUT OF THE CENTRAL
PLAINS AROUND THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
AS OF 1035 PM EST MONDAY...
OVERALL MID DECK CANOPY CONTINUES ACROSS THE REGION TONIGHT WITH
DRY AIR LIMITING BASES TO 8 KFT AND ABOVE. RADAR IS ALSO
INDICATING LIGHT RETURNS MAKING THEIR WAY ACROSS THE FAR SW
MOUNTAINS INTO THE AREA...BUT WITH THE LOW LEVELS STILL VERY
DRY...DO NOT SEE MORE THAN LIGHT SPRINKLES OR A FEW SLEET PELLETS
MAKING IT TO THE SURFACE UNTIL THE EARLY MORNING HOURS OF TUESDAY
AS THE NEXT WAVE APPROACHES.
MODELS CONTINUE TO SLOW DOWN ANY EASTWARD PROGRESSION OF PRECIP
OVERNIGHT...LIKELY DUE TO SO MUCH DRY AIR AND ONLY LIGHT PRECIP
GIVEN A LACK OF A WELL DEFINED SURFACE SYSTEM. GUIDANCE ALSO
REMAINS A BIT WARMER PER LESS EVAPORATIVE COOLING PROVIDED BY
ONLY VERY LIGHT PRECIP WITH EVEN THE LATEST RAP AND LOCAL WRF
SOLUTIONS QUITE DRY UNTIL SHORTLY BEFORE DAYBREAK.
HOWEVER...EARLIER MODEL INIT REMAINS ALL OVER THE PLACE UNDER
SUCH A STRUNG OUT AREA OF DEEP MOISTURE ALONG THE SRN JET AND
LIKELY HAVING A HARD TIME IN WHERE TO FOCUS PRECIP ATTM. THUS HAVE
KEPT IN LIGHT MIXED PRECIP FOR MANY OF THE WESTERN SITES WITH
PERHAPS A PERIOD OF VERY LIGHT FREEZING RAIN POSSIBLE IN THE
VALLEYS AT KLWB/KBCB TOWARD DAWN BUT CONFIDENCE LOW. OTRW
INCLUDING A BIT MORE IN THE WAY OF PL MENTION AT LEAST AT THE
ONSET OVERNIGHT ACROSS THE WEST WHILE LEAVING THINGS MAINLY VFR
UNTIL VERY LATE TONIGHT WITH ONLY SPOTTY -RA OUT EAST.
PRECIPITATION WILL BECOME WIDESPREAD TUESDAY MORNING WITH A MUCH
BETTER PROBABILITY OF MVFR OR EVEN IFR CONDITIONS...AND LOW TO
MEDIUM CONFIDENCE THAT SITES FROM KBCB WESTWARD WILL SEE MIXED
PRECIPITATION CHANGE TO RAIN BY LATE MORNING AS TEMPERATURES WARM.
HOWEVER KLWB MAY GET STUCK AROUND FREEZING INTO THE AFTERNOON SO
MAY BE TOUGH TO DISLODGE THE MIXED BAG THERE UNTIL PRECIP TAPERS
OFF IN THE AFTERNOON. AS A SURFACE LOW PRESSURE SYSTEM PASSES
THROUGH THE CAROLINAS TUESDAY AND TUESDAY NIGHT...COLDER AIR WILL
MOVE INTO THE AREA. ON TUESDAY EVENING PRECIPITATION WILL CHANGE
TO SNOW SHOWERS...WHICH WILL CONTINUE IN SOUTHEAST WEST
VIRGINIA...INCLUDING KLWB AND KBLF INTO EARLY WEDNESDAY MORNING.
COULD EVEN BE SOME SPOTTY LIGHT FREEZING RAIN OR PERHAPS SOME
LIGHT SNOW FROM KBCB/KROA TO KLYH TUE NIGHT AS THE PRECIP ENDS.
OTRW APPEARS IFR TO OCNL MVFR CIGS WILL PERSIST ACROSS MOST OF
THE AREA TUESDAY NIGHT OR EARLY WEDNESDAY UNDER SLOWLY IMPROVING
VSBYS AS PRECIPS ENDS OVERNIGHT.
VFR WEATHER IS EXPECTED WEDNESDAY AFTERNOON INTO SATURDAY FOR
MOST OF THE REGION. A LOW PRESSURE SYSTEM PASSING WELL TO THE
SOUTH MAY BRING SUB-VFR CONDITIONS TO DAN ON THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...KK
AVIATION...AMS/JH/NF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
339 AM CST TUE JAN 1 2013
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
339 AM CST TUE JAN 1 2013
FORECAST CONCERNS THIS PACKAGE...WIND CHILLS THIS MORNING...LIGHT
SNOW CHANCES WED/WED NIGHT...TEMPERATURES THRU THE PERIOD.
06Z DATA ANALYSIS HAD HIGH PRESSURE CENTERED OVER SOUTHWEST MN AND
WESTERN IA...DRIFTING SLOWLY SOUTHEAST. SKIES WERE CLEAR OVER
MN/IA/WI EAST OF THE SFC-850MB RIDGE AXIS. WITH CLEAR SKIES...LIGHT
WINDS AND SNOW COVER...TEMPS WERE FALLING BELOW ZERO ACROSS MUCH OF
MN/WESTERN WI/NORTHERN IA FOR SOME OF THE COLDEST TEMPS SO FAR THIS
WINTER SEASON. WINDS ACROSS MUCH OF MN/IA/WI LIGHTER THAN EARLIER
EXPECTED...WITH MOST WIND CHILLS EARLY THIS MORNING IN THE 0 TO -20
RANGE. WEST OF THE RIDGE AXIS...A STRATUS DECK WAS SPREADING EAST
INTO SOUTHWEST MN/NORTHWEST IA.
MODELS AGAIN LOOK TO HAVE INITIALIZED WELL FOR THEIR 01.00Z RUNS.
SOLUTIONS AND SENSIBLE WEATHER OUTCOMES VERY SIMILAR THRU THE SHORT-
TERM PERIOD THIS CYCLE. DPROG/DT OF 500MB HGTS AT 01.00Z SHOWED THE
MODEL RUNS OF 30.00Z AND 31.00Z VERIFIED WELL WITH THE LARGE SCALE
FLOW ACROSS NOAM/EASTERN PAC...BUT WERE A BIT SLOW/STRONG WITH THE
SHORTWAVE FEATURE SHEARING NORTHEAST ACROSS THE CENTRAL PLAINS AND
TOO WEAK/FAST WITH THE FEATURE ON THE OR COAST. SOMEWHAT BETTER
RUN-TO-RUN CONSISTENCY BY GFS THIS CYCLE. TRENDS OF THE FEATURES
MENTIONED ABOVE HAVE LITTLE IF ANY IMPACT ON THE AREAS SHORT-TERM
WEATHER. BETTER CONSISTENCY SEEN WITH THE SHORTWAVE TO DROP INTO THE
NORTHERN PLAINS/UPPER MIDWEST TODAY/TONIGHT THEN SLIDE ACROSS THE
REGION WED/WED NIGHT. TREND FAVORS FASTER OF EARLIER RUNS...WITH A
MORE OPEN WAVE PASSING WED/WED NIGHT. MORE PROGRESSIVE PATTERN HAS
MORE RIDGING ALOFT BUILDING INTO THE REGION BY THU NIGHT/FRI. CHECK
OF OBS VS. MODEL DATA AT 06Z SHOWED ALL REASONABLE WITH THE SFC MASS
FIELDS OVER THE CENTRAL CONUS. MODELS ACTUALLY DOING ABOUT AS WELL
AS CAN BE EXPECTED WITH THE STRATUS CLOUDS SPREADING INTO SOUTHWEST
MN/NORTHWEST IA EARLY THIS MORNING. PER WV IMAGERY ALL LOOKED GOOD
WITH THE SHORTWAVE DETAILS OVER NOAM/EASTERN PAC. HIGHER-RES
MODELS DOING BETTER WITH THE CHILLY TEMPS ACROSS MN/IA/WI EARLY
THIS MORNING WHILE COARSER RESOLUTION MODELS ON THE WARM SIDE.
OVERALL NO ONE FAVORITE MODEL AND WITH ALL SHOWING SIMILAR TREND
TOWARD A COMMON CONSENSUS OUT TO WED NIGHT/THU...FAVORED THE
MODEL/ENSEMBLE CONSENSUS. SHORT-TERM FCST CONFIDENCE REMAINS GOOD
THIS CYCLE.
FOR THE SHORT TERM...WHAT TO DO WITH THE WIND CHILL ADVISORY IS AN
ISSUE EARLY THIS MORNING. WITH LIGHTER WINDS THAN EARLIER
EXPECTED...WIND CHILLS ARE STAYING MOSTLY ABOVE THE -20 MARK. WITH
THE LIGHTER WINDS...TEMPS TRENDING COLDER MANY LOCATIONS. WITH THE
COLDER TEMPS...ANY WIND AT ALL THRU ABOUT 15Z WOULD SEND WIND CHILLS
BELOW -20. THUS WILL HANG ONTO ADVISORY FOR NOW. NEXT ISSUE IS THE
MOISTURE/CLOUDS MOVING TOWARD THE AREA FROM EASTERN SD. MODELS
BRING THIS MOISTURE INTO THE WEST SIDE OF THE FCST AREA LATE THIS
MORNING...ACROSS MAINLY THE NORTHWEST 2/3 OF THE FCST AREA THIS
AFTERNOON THEN MOVE IT EAST OF THE FCST AREA TONIGHT. TRENDED SKY
GRIDS TO ACCOUNT FOR THESE CLOUDS TODAY/TONIGHT. LOW LEVEL WARM
ADVECTION SPREADS ACROSS THE AREA TONIGHT WITH 925MB TEMPS IN THE -5
TO -9C RANGE BY 12Z WED. THIS ALONG WITH SOME SOUTHWEST GRADIENT
WINDS AHEAD OF THE NEXT LOW/TROUGH MOVING ACROSS THE DAKOTAS INTO MN
WILL KEEP TEMPS WARMER TONIGHT...EVEN AS SKIES BECOME MOSTLY CLEAR
AFTER MIDNIGHT.
MOISTURE WITH THE NEXT SFC-MID LEVEL TROUGH SPREADS SOUTHEAST ACROSS
THE FCST AREA ON WED. WHAT LOWER LEVEL THERMO-DYNAMIC FORCING THERE
IS MOSTLY MOVES ACROSS THE FCST AREA BEFORE THE DEEPER MOISTURE
ARRIVES. MODELS SHOW THE COLUMN SATURATES TO AT LEAST 700MB THRU
THU AFTERNOON/EVENING WITH AND AHEAD OF THE PASSING SFC-MID LEVEL
TROUGH AXIS. MODEL CONSENSUS DOES HAVE SOME 500-300MB PV ADVECTION
MOVING ACROSS THE AREA CENTERED ON 00Z THU ALONG WITH SOME WEAK
700-500MB QG CONVERGENCE. GIVEN THE MOISTURE SIGNAL...THE WEAK
QG CONVERGENCE...RATHER DEEP CYCLONIC FLOW FOR CONVERGENCE AND SOME
PV ADVECTION/DIVERGENCE ALOFT...MAINTAINED TREND OF VERY LIGHT SNOW
LIKELY OVER THE NORTHWEST HALF OF THE FCST AREA WED AFTERNOON AND
THE NORTHEAST 3/4 WED EVENING AS THE TROUGH APPROACHES/PASSES. ANY
SNOW AMOUNTS FROM THIS SYSTEM STILL LOOK LIKE A DUSTING UP TO A HALF
INCH. WITH SOME SFC-700MB MOISTURE AND CYCLONIC FLOW/CONVERGENCE
LINGERING LATER WED NIGHT...ADDED MENTION OF SCT FLURRIES TO 06Z-
12Z THU FCST GRIDS.
SUBSIDENCE/DRYING SPREAD ACROSS THE AREA THU. LOWER LEVEL COLD
ADVECTION WED NIGHT/MUCH OF THU SENDS 925MB TEMPS BACK INTO THE -11C
TO -14C RANGE FOR THU AFTERNOON. TEMPS LOOKING TO END UP NEARLY
STEADY ON THU. WITH THE MORE PROGRESSIVE TROUGH AND MID LEVEL
RIDGING BUILDING EAST INTO THE UPPER MIDWEST...MDT/STRONG 925-850MB
WARM ADVECTION SPREADS ACROSS MN/IA/WI THU NIGHT. DEPENDING ON
PRESSURE GRADIENT/BOUNDARY LAYER WINDS FOR MIXING AND STRENGTH OF
LOW LEVEL INVERSION...LOWS THU NIGHT MAY BE IN THE EVENING WITH
RISING TEMPS AFTER MIDNIGHT. THIS TREND CAN BE ADDED TO FCST GRIDS
LATER AS DETAILS BECOME CLEARER.
USING A MODEL/ENSEMBLE CONSENSUS...GENERALLY FAVORED A BLEND OF THE
NUMERICAL TEMP GUIDANCE FOR HIGHS/LOWS TODAY THRU THU NIGHT. WITH
CLOUDS AND SOME GRADIENT WINDS FOR MIXING...DID LEAN TOWARD WARMER
OF GUIDANCE LOWS WED NIGHT.
.LONG TERM...FRIDAY THROUGH MONDAY
339 AM CST TUE JAN 1 2013
01.00Z MEDIUM RANGE MODELS IN BETTER AGREEMENT WITH EACH OTHER
FRI/SAT AS RIDGING BUILDS ACROSS THE REGION FRI THEN A DEEPENING
TROUGH MOVES ACROSS ON SAT. SOME CONSENSUS FOR WEAK AND TRANSIENT
SHORTWAVE RIDGING OVER THE UPPER MIDWEST SUN BEFORE ANOTHER NORTHERN
STREAM...WEST/ NORTHWEST FLOW SHORTWAVE TROUGH MOVES INTO THE REGION
MONDAY. LONG-TERM FCST CONFIDENCE IS AVERAGE.
BULK OF THE ENERGY WITH THE SAT TROUGH LOOKS TO PASS WEST/SOUTH OF
THE FCST AREA...WITH MOISTURE ALSO TRENDING TO BE ON THE LIMITED
SIDE. PER MODEL CONSENSUS...LEFT SAT DRY. THE MONDAY SYSTEM ALSO
LOOKS MOISTURE STARVED AT THIS TIME WITH BULK OF THE ENERGY PASSING
WELL NORTH OF THE FCST AREA AND SOURCE REGION FOR THE LOWER LEVEL
AIRMASS THE CENTRAL/NORTHERN PLAINS. LEFT MON DRY AS WELL. WITH THE
POLAR JET SHIFTING NORTH OF THE AREA...KEEPING THE ARCTIC AIR
BOTTLED UP IN NORTHERN/EASTERN CAN...TEMPS FOR FRI THRU MONDAY
LOOKING TO MODERATE WITH REPEATED ROUNDS OF LOW LEVEL WARM ADVECTION
AND PREVAILING FLOW MAINLY WESTERLY. PERHAPS A BRIEF COOL-DOWN WITH
THE PASSING TROUGH SAT/SAT NIGHT BUT MDT/STRONG LOW LEVEL WARM
ADVECTION QUICKLY RETURNS FOR SUN. GIVEN PLENTY OF DETAIL
DIFFERENCES...MODEL/ENSEMBLE CONSENSUS HIGHS/LOWS FOR FRI-MON LOOK
GOOD AT THIS TIME.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1117 PM CST MON DEC 31 2012
CLOUD DECK OVER SOUTH DAKOTA ON THE BACK SIDE OF THE RIDGE AXIS
CONTINUES TO HOLD TOGETHER THIS EVENING. IT HAS BEEN SLOWLY MOVING
EAST AND THE 01.00Z NAM NOW SUGGESTS THIS MOISTURE FIELD WILL MOVE
OVER THE AREA TUESDAY AFTERNOON. THE 01.03Z RAP ALSO SHOWS THIS
TREND SO WILL INCLUDE A MVFR CEILING DEVELOPING AT KRST AROUND 18Z
AND KLSE AROUND 21Z. ONCE IT IS IN PLACE...WOULD EXPECT IT TO
PERSIST THROUGH THE EVENING. VFR CONDITIONS WILL PREVAIL UNTIL THE
CLOUDS ARRIVE WITH THE WINDS SLOWLY COMING AROUND TO THE SOUTHWEST
ON THE BACK SIDE OF THE RIDGE AXIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
339 AM CST TUE JAN 1 2013
WI...NONE.
MN...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ079-
086>088-094>096.
IA...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ008>
010-018-019-029.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1117 PM CST MON DEC 31 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
210 PM CST MON DEC 31 2012
FORECAST FOCUS IS ON THE DANGEROUS WIND CHILLS TONIGHT...THEN THE
LIGHT SNOW CHANCES FOR WED/WED NIGHT.
COLD AIR IS MOVING IN...WITH 850 MB TEMPS EXPECTED TO TUMBLE FROM
-10 C THIS AFTERNOON TO -14 C BY TUE MORNING. WITH MOSTLY CLEAR
SKIES AIDED BY HIGH PRESSURE BUILDING IN FROM THE
PLAINS...RADIATIONAL COOLING WILL HELP TEMPS FALL OFF A FEW MORE
DEGREES. MORNING LOWS WILL BE IN THE SINGLE DIGITS/LOW TEENS BELOW
ZERO. WINDS WILL LIGHTEN UP...BUT STIR ENOUGH IN OPEN AND
UNSHELTERED AREAS THAT WIND CHILLS WILL BE A WEATHER CONCERN.
SOUTHEAST MN/NORTHEAST IA CAN EXPECT 20 TO 25 BELOW WIND CHILLS FROM
MIDNIGHT THROUGH ABOUT MID MORNING ON NEW YEARS. DANGEROUS ON A
NORMAL NIGHT...MORE SO WITH NEW YEAR/S EVE DRAWING MANY MANY PEOPLE
OUT FOR THE EVENING. WIND CHILL ADVISORIES WILL CONTINUE FOR THE
AFOREMENTIONED AREAS.
NAM/GFS/ECMWF HAVE BEEN CONSISTENT IN SLIDING A TROUGH ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY FOR WED/WED NIGHT...WITH A PIECE OF
ENERGY SPINNING ACROSS IOWA AND ANOTHER STAYING NORTH...ACROSS
SOUTHERN CANADA. DECENT QG CONVERGENT RESPONSE IN THE 300-500 MB
LAYER BETWEEN 18Z WED-06Z THU TIME FRAME VIA THE GFS/NAM...BUT NOT
MUCH THERMODYNAMIC FORCING. NORTHWEST-SOUTHEAST RUNNING X-SECTIONS
SATURATE THROUGH AT LEAST 600 MB AS THE TROUGH MOVES IN...A BIT
DEEPER IN THE GFS. DENDRITIC ZONE GROWTH REGION IS SMALL...BUT COLD
ENOUGH FOR ICE AND THUS SNOW FOR PCPN TYPE. AN ASSOCIATED SFC
BOUNDARY WITH THE UPPER LEVEL FORCING WILL MOVE ACROSS THE FORECAST
AREA IN THE LATE AFTERNOON/EARLY EVENING HOURS...WHICH COULD AID IN
LIFT ALTHOUGH LITTLE 2-D FRONTOGENETIC RESPONSE IS INDICATED AT THIS
TIME. OVERALL...DYNAMICS ARE RATHER WEAK AS THE TROUGH MOVES ACROSS
THE FORECAST AREA. THAT SAID...THERE LOOKS TO BE ENOUGH SATURATION
FOR THE SHORTWAVE TO TAP INTO AND PRODUCE SOME LIGHT SNOW. THIS IS
SHAPING UP TO BE A WIDESPREAD VERY LIGHT SNOW/FLURRY EVENT WITH
MINIMAL IF ANY ACCUMULATION.
.LONG TERM...FRIDAY THROUGH MONDAY
210 PM CST MON DEC 31 2012
SIZABLE DIFFERENCES FOR THE UPCOMING WEEKEND WITH THE GFS AND GEM
BRINGING A SHORTWAVE INTO THE PAC NW...DRIVING IT EASTWARD TO ACROSS
THE REGION ON SAT. BOTH MODELS DROP MORE ENERGY FROM NORTHERN CANADA
INTO THE WAVE...HELPING DEEPENING THE TROUGH AS IT APPROACHES.
MEANWHILE THE ECMWF IS MUCH SLOWER WITH THIS PAC NW SHORTWAVE...NOT
BRINGING IT ACROSS THE AREA UNTIL SUNDAY NIGHT. IT ALSO NEVER
DEVELOPS A CONNECTION TO ANY ENERGY FARTHER NORTH. NOT MUCH QPF
PRODUCED VIA THE GFS/GEM...WITH NONE VIA THE EC. WITHOUT A LOT OF
CONFIDENCE IN EITHER OF THE SOLUTIONS...WILL STICK WITH THE
CONSENSUS SOLUTION FOR NOW.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1117 PM CST MON DEC 31 2012
CLOUD DECK OVER SOUTH DAKOTA ON THE BACK SIDE OF THE RIDGE AXIS
CONTINUES TO HOLD TOGETHER THIS EVENING. IT HAS BEEN SLOWLY MOVING
EAST AND THE 01.00Z NAM NOW SUGGESTS THIS MOISTURE FIELD WILL MOVE
OVER THE AREA TUESDAY AFTERNOON. THE 01.03Z RAP ALSO SHOWS THIS
TREND SO WILL INCLUDE A MVFR CEILING DEVELOPING AT KRST AROUND 18Z
AND KLSE AROUND 21Z. ONCE IT IS IN PLACE...WOULD EXPECT IT TO
PERSIST THROUGH THE EVENING. VFR CONDITIONS WILL PREVAIL UNTIL THE
CLOUDS ARRIVE WITH THE WINDS SLOWLY COMING AROUND TO THE SOUTHWEST
ON THE BACK SIDE OF THE RIDGE AXIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
210 PM CST MON DEC 31 2012
WI...NONE.
MN...WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST
TUESDAY FOR MNZ079-086>088-094>096.
IA...WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST
TUESDAY FOR IAZ008>010-018-019-029.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1041 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL PROVIDE THE RISK FOR SNOW SHOWERS THROUGH THE
MORNING HOURS. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
BEGINNING THIS AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE STILL VERY UNIMPRESSIVE PRECIPITATION REGIME OVER THE AREA IS
BEING DRIVEN BY WHAT WOULD SEEMINGLY BE VERY IMPRESSIVE DYNAMICS
THIS MORNING. THE 12Z KPBZ RAOB INDICATED A NEARLY 190 KT JET
OVERHEAD...WHICH IS VERY IMPRESSIVE FOR ANY TIME OF THE
YEAR...WHILE A VERY STRONG LOW LEVEL THERMAL GRADIENT WAS EVIDENT
OVER THE LOWER GREAT LAKES AS WELL. TEMPERATURES FROM THE MID-
MISSISSIPPI VALLEY TO THE UPPER OHIO VALLEY GENERALLY WERE IN THE
UPPER 20S TO LOWER 30S...WHILE JUST TO THE NORTH IN THE GREAT
LAKES REGION...TEMPERATURES WERE GENERALLY 0 TO -15F AS OF THE
LAST FEW HOURS. THE LEADING EDGE OF THE COLDER AIR AS PROGRESSED
SLOWLY SOUTHWARD INTO OHIO AND NORTHWESTERN PENNSYLVANIA THIS
MORNING...HOWEVER IT REALLY WILL NEED AN ADDITIONAL KICK TO MOVE
FARTHER.
THE KICK TO THE FRONT LOOKS TO COME THROUGH THIS AFTERNOON AS A
FAIRLY POTENT MID-LEVEL WAVE TRACKS DOWN THE FRONTAL ZONE THROUGH
THE VERY HIGH SPEED UPPER FLOW. COLD AIR ADVECTION LOOKS TO KICK
IN BEHIND IT...WHICH WOULD MAKE OUR DIURNALS TODAY JUST ABOUT
ZILCH. AS SUCH...POPS WERE FOCUSED AHEAD OF THIS WAVE AND SOUTH OF
THE FRONTAL ZONE THROUGH THE DAY. WHILE POPS ARE FAIRLY HIGH...QPF
AND SNOW AMOUNTS ARE NOT. AS A CONTINUATION FROM LAST EVENING AND
LAST NIGHT`S ACTIVITY...ICE MICROPHYSICS ARE QUITE POOR. AS
SUCH...IT SEEMS UNLIKELY THAT ANYONE WILL SEE ANYTHING MORE THAN
AN INCH TODAY...WHILE MOST AREAS SEE MUCH LESS. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
FLOW ALOFT BEGINS TO WANE TONIGHT...BUT THE COLD AIR WILL CONTINUE
TO PLUNGE INTO THE AREA. STRONG HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST. WILL LEAVE IN CLOUDS OVERNIGHT...BUT WITH INVERSIONS SO
LOW...ONLY EXPECT SNOW SHOWERS IN THE RIDGES.
TEMPS OVERNIGHT WILL BE WELL BELOW NORMAL.
SFC HIGH PRESSURE WILL MOVE FROM THE MIDWEST INTO THE OHIO VALLEY
ON WED. THE CORE OF THE COLD POOL WILL BEGIN TO MOVE NORTHEASTWARD
AS 85H RIDGES MOVE EASTWARD. STILL EXPECT LOTS OF CLOUDS WED...BUT
THERE WILL BE SOME IMPROVEMENT IN THE AFTERNOON.
TEMPS AGAIN...WELL BELOW NORMAL.
ANOTHER SHORTWAVE TROUGH WILL SWING THROUGH LATE THURSDAY.
WITH WINDS VEERING TO THE WEST-SOUTHWEST...TEMPS WILL MODERATE A
BIT ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
GENERAL AGREEMENT IN THE MODELS ON THE OVERALL PATTERN THROUGH THE
LONG TERM PD...ALTHOUGH PREFER GEFS/NAEFS FOR TIMING OF INDIVIDUAL
FEATURES.
A WK COLD FRONT WL MOVE ACRS THE RGN THU NT...HOWEVER DEEP MOISTURE
IS CONFINED WELL TO THE NORTH. COULD SEE A FEW SHSN IN NW FLOW
BEHIND THE FRONT BUT INVERSION SHOULD LIMIT DEPTH OF CLOUDS TO KEEP
ACTIVITY MINIMAL...SO KEPT ONLY LOW CHC POPS N OF PIT. HIGH PRES
BLDS IN SAT BEFORE ANOTHER WK FRONT PASSES THROUGH SAT NT...AGAIN
WITH MOST OF THE MOISTURE STAYING NORTH. THIS SHOULD BRING MAINLY
JUST AN INCREASE IN CLOUDS. HIGH PRES RIDGES BACK IN MON.
TEMPS WL AVG BLW NORMAL MOST OF THE PD. OPERATIONAL MODELS WARM
THINGS UP MON...BUT ENSEMBLES ARE NOT AS AGGRESSIVE. STAYED CLOSER TO
COOLER ENSEMBLE MEANS.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT RAP NAM
AND SREF MODEL OUTPUT SHOW JETSTREAK-RELATED COLD FRONTAL BAND OF
LIGHT IFR SNOW WILL CONTINUE TO PASS EASTWARD THROUGH THE UPPER OHIO
VALLEY THROUGH ABOUT 17Z.
POSTFRONTAL COLD POOL COUPLED WITH LAKE-MOISTENED WEST TO NORTHWEST
SURFACE LAYER WINDS WILL MAINTAIN MVFR CONDITIONS INTO TONIGHT. ANY
REMAINING PRECIPITATION...BE IT SNOW OR FREEZING DRIZZLE...WILL BE
VERY LIGHT AS SURFACE MIXED LAYER WILL BE CAPPED AT 5 KFT AGL.
SURFACE WINDS WILL GO FROM SOUTHWEST TO WEST AT 8 KTS THIS MORNING...TO
NORTHWEST AT 10 KTS THIS AFTERNOON...THEN BECOME WESTERLY AT NO
MORE THAN 6 KTS TONIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
COLD POOL MVFR STRATOCUMULUS WILL REMAIN THROUGH AT LEAST WEDNESDAY.
HIGH PRESSURE SUBSIDENCE MAY PROMOTE A VFR BREAK THURSDAY BEFORE A
COLD FRONT PROVIDES THE NEXT ROUND OF RESTRICTIONS FRIDAY AND
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
800 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL PROVIDE THE RISK FOR SNOW SHOWERS THROUGH THE
MORNING HOURS. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
BEGINNING THIS AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUICK MRNG UPDATE TO INCRS POPS ACRS THE SRN CWA BASED ON
RADAR/SFC OBS. NO OTHER CHGS ATTM.
PREVIOUS...
FRONT IS SLOWLY MOVING INTO NW PA AND WILL CONTINUE
IT ARDUOUS TREK SOUTHWARD. LIGHT SNOW SHOWERS HAVE REDEVELOPED ON
THE SOUTHERN FLANK OF THE BOUNDARY AS A STRONG UPPER LEVEL WAVE IS
RUNNING ALONG THE NORTHERN SIDE OF THE FRONT AND PROVIDING LIFT.
THIS WAVE WILL ALSO HELP TO GET THE FRONT MOVING SOUTHWARD...WHICH
WILL EVENTUALLY PUSH THE LIGHT SNOW SHOWER ACTIVITY TO THE SOUTH.
BY THIS AFTERNOON...THE FRONT WILL HAVE MADE IT INTO THE MID-
ATLANTIC REGION. STRONG CAA AND NORTHWEST FLOW IN THE WAKE OF THE
FRONT WILL KEEP THE AREA BLANKETED WITH CLOUDS. THERE LIKELY BE
SOME LAKE EFFECT/ENHANCED SNOW SHOWERS DEVELOPING LATER TODAY.
HOWEVER DO NOT THINK ACTIVITY WILL BE WIDESPREAD AS INVERSIONS DROP
QUICKLY THIS AFTERNOON. WILL KEEP HIGHEST POPS OVER THE RIDGES AS
THERE IS AN OROGRAPHIC COMPONENT THIS AFTERNOON.
WITH THE STRONG CAA EXPECT STEADY TO SLOWLY FALLING TEMPS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
FLOW ALOFT BEGINS TO WANE TONIGHT...BUT THE COLD AIR WILL CONTINUE
TO PLUNGE INTO THE AREA. STRONG HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST. WILL LEAVE IN CLOUDS OVERNIGHT...BUT WITH INVERSIONS SO
LOW...ONLY EXPECT SNOW SHOWERS IN THE RIDGES.
TEMPS OVERNIGHT WILL BE WELL BELOW NORMAL.
SFC HIGH PRESSURE WILL MOVE FROM THE MIDWEST INTO THE OHIO VALLEY
ON WED. THE CORE OF THE COLD POOL WILL BEGIN TO MOVE NORTHEASTWARD
AS 85H RIDGES MOVE EASTWARD. STILL EXPECT LOTS OF CLOUDS WED...BUT
THERE WILL BE SOME IMPROVEMENT IN THE AFTERNOON.
TEMPS AGAIN...WELL BELOW NORMAL.
ANOTHER SHORTWAVE TROUGH WILL SWING THROUGH LATE THURSDAY.
WITH WINDS VEERING TO THE WEST-SOUTHWEST...TEMPS WILL MODERATE A
BIT ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
GENERAL AGREEMENT IN THE MODELS ON THE OVERALL PATTERN THROUGH THE
LONG TERM PD...ALTHOUGH PREFER GEFS/NAEFS FOR TIMING OF INDIVIDUAL
FEATURES.
A WK COLD FRONT WL MOVE ACRS THE RGN THU NT...HOWEVER DEEP MOISTURE
IS CONFINED WELL TO THE NORTH. COULD SEE A FEW SHSN IN NW FLOW
BEHIND THE FRONT BUT INVERSION SHOULD LIMIT DEPTH OF CLOUDS TO KEEP
ACTIVITY MINIMAL...SO KEPT ONLY LOW CHC POPS N OF PIT. HIGH PRES
BLDS IN SAT BEFORE ANOTHER WK FRONT PASSES THROUGH SAT NT...AGAIN
WITH MOST OF THE MOISTURE STAYING NORTH. THIS SHOULD BRING MAINLY
JUST AN INCREASE IN CLOUDS. HIGH PRES RIDGES BACK IN MON.
TEMPS WL AVG BLW NORMAL MOST OF THE PD. OPERATIONAL MODELS WARM
THINGS UP MON...BUT ENSEMBLES ARE NOT AS AGGRESSIVE. STAYED CLOSER TO
COOLER ENSEMBLE MEANS.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT RAP NAM
AND SREF MODEL OUTPUT SHOW JETSTREAK-RELATED COLD FRONTAL BAND OF
LIGHT IFR SNOW WILL CONTINUE TO PASS EASTWARD THROUGH THE UPPER OHIO
VALLEY THROUGH ABOUT 17Z.
POSTFRONTAL COLD POOL COUPLED WITH LAKE-MOISTENED WEST TO NORTHWEST
SURFACE LAYER WINDS WILL MAINTAIN MVFR CONDITIONS INTO TONIGHT. ANY
REMAINING PRECIPITATION...BE IT SNOW OR FREEZING DRIZZLE...WILL BE
VERY LIGHT AS SURFACE MIXED LAYER WILL BE CAPPED AT 5 KFT AGL.
SURFACE WINDS WILL GO FROM SOUTHWEST TO WEST AT 8 KTS THIS MORNING...TO
NORTHWEST AT 10 KTS THIS AFTERNOON...THEN BECOME WESTERLY AT NO
MORE THAN 6 KTS TONIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
COLD POOL MVFR STRATOCUMULUS WILL REMAIN THROUGH AT LEAST WEDNESDAY.
HIGH PRESSURE SUBSIDENCE MAY PROMOTE A VFR BREAK THURSDAY BEFORE A
COLD FRONT PROVIDES THE NEXT ROUND OF RESTRICTIONS FRIDAY AND
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
646 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL PROVIDE THE RISK FOR SNOW SHOWERS THROUGH THE
MORNING HOURS. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
BEGINNING THIS AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FRONT IS SLOWLY MOVING INTO NW PA AND WILL CONTINUE IT ARDUOUS
TREK SOUTHWARD. LIGHT SNOW SHOWERS HAVE REDEVELOPED ON THE
SOUTHERN FLANK OF THE BOUNDARY AS A STRONG UPPER LEVEL WAVE IS
RUNNING ALONG THE NORTHERN SIDE OF THE FRONT AND PROVIDING LIFT.
THIS WAVE WILL ALSO HELP TO GET THE FRONT MOVING SOUTHWARD...WHICH
WILL EVENTUALLY PUSH THE LIGHT SNOW SHOWER ACTIVITY TO THE SOUTH.
BY THIS AFTERNOON...THE FRONT WILL HAVE MADE IT INTO THE MID-
ATLANTIC REGION. STRONG CAA AND NORTHWEST FLOW IN THE WAKE OF THE
FRONT WILL KEEP THE AREA BLANKETED WITH CLOUDS. THERE LIKELY BE
SOME LAKE EFFECT/ENHANCED SNOW SHOWERS DEVELOPING LATER TODAY.
HOWEVER DO NOT THINK ACTIVITY WILL BE WIDESPREAD AS INVERSIONS DROP
QUICKLY THIS AFTERNOON. WILL KEEP HIGHEST POPS OVER THE RIDGES AS
THERE IS AN OROGRAPHIC COMPONENT THIS AFTERNOON.
WITH THE STRONG CAA EXPECT STEADY TO SLOWLY FALLING TEMPS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
FLOW ALOFT BEGINS TO WANE TONIGHT...BUT THE COLD AIR WILL CONTINUE
TO PLUNGE INTO THE AREA. STRONG HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST. WILL LEAVE IN CLOUDS OVERNIGHT...BUT WITH INVERSIONS SO
LOW...ONLY EXPECT SNOW SHOWERS IN THE RIDGES.
TEMPS OVERNIGHT WILL BE WELL BELOW NORMAL.
SFC HIGH PRESSURE WILL MOVE FROM THE MIDWEST INTO THE OHIO VALLEY
ON WED. THE CORE OF THE COLD POOL WILL BEGIN TO MOVE NORTHEASTWARD
AS 85H RIDGES MOVE EASTWARD. STILL EXPECT LOTS OF CLOUDS WED...BUT
THERE WILL BE SOME IMPROVEMENT IN THE AFTERNOON.
TEMPS AGAIN...WELL BELOW NORMAL.
ANOTHER SHORTWAVE TROUGH WILL SWING THROUGH LATE THURSDAY.
WITH WINDS VEERING TO THE WEST-SOUTHWEST...TEMPS WILL MODERATE A
BIT ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
GENERAL AGREEMENT IN THE MODELS ON THE OVERALL PATTERN THROUGH THE
LONG TERM PD...ALTHOUGH PREFER GEFS/NAEFS FOR TIMING OF INDIVIDUAL
FEATURES.
A WK COLD FRONT WL MOVE ACRS THE RGN THU NT...HOWEVER DEEP MOISTURE
IS CONFINED WELL TO THE NORTH. COULD SEE A FEW SHSN IN NW FLOW
BEHIND THE FRONT BUT INVERSION SHOULD LIMIT DEPTH OF CLOUDS TO KEEP
ACTIVITY MINIMAL...SO KEPT ONLY LOW CHC POPS N OF PIT. HIGH PRES
BLDS IN SAT BEFORE ANOTHER WK FRONT PASSES THROUGH SAT NT...AGAIN
WITH MOST OF THE MOISTURE STAYING NORTH. THIS SHOULD BRING MAINLY
JUST AN INCREASE IN CLOUDS. HIGH PRES RIDGES BACK IN MON.
TEMPS WL AVG BLW NORMAL MOST OF THE PD. OPERATIONAL MODELS WARM
THINGS UP MON...BUT ENSEMBLES ARE NOT AS AGGRESSIVE. STAYED CLOSER TO
COOLER ENSEMBLE MEANS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT RAP NAM
AND SREF MODEL OUTPUT SHOW JETSTREAK-RELATED COLD FRONTAL BAND OF
LIGHT IFR SNOW WILL CONTINUE TO PASS EASTWARD THROUGH THE UPPER OHIO
VALLEY THROUGH ABOUT 17Z.
POSTFRONTAL COLD POOL COUPLED WITH LAKE-MOISTENED WEST TO NORTHWEST
SURFACE LAYER WINDS WILL MAINTAIN MVFR CONDITIONS INTO TONIGHT. ANY
REMAINING PRECIPITATION...BE IT SNOW OR FREEZING DRIZZLE...WILL BE
VERY LIGHT AS SURFACE MIXED LAYER WILL BE CAPPED AT 5 KFT AGL.
SURFACE WINDS WILL GO FROM SOUTHWEST TO WEST AT 8 KTS THIS MORNING...TO
NORTHWEST AT 10 KTS THIS AFTERNOON...THEN BECOME WESTERLY AT NO
MORE THAN 6 KTS TONIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
COLD POOL MVFR STRATOCUMULUS WILL REMAIN THROUGH AT LEAST WEDNESDAY.
HIGH PRESSURE SUBSIDENCE MAY PROMOTE A VFR BREAK THURSDAY BEFORE A
COLD FRONT PROVIDES THE NEXT ROUND OF RESTRICTIONS FRIDAY AND
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
513 AM CST TUE JAN 1 2013
.DISCUSSION...
OVERVIEW...NEAR TO BELOW NORMAL TEMPS THIS WEEK. LIGHT SNOW EVENT
STILL ON TAP FOR WEDNESDAY WHERE WE HAVE LIKELY TO CATEGORICAL
POPS FOR LIGHT SNOW.
STRATUS OVER WESTERN MN CONTINUES TO THE EAST AT 10 KTS SO TRIED
TO TREND TEMPERATURES...DEWPOINTS...AND SKY COVER ACCORDINGLY.
WIND HAS WEAKENED QUITE A BIT OVERNIGHT WITH THE HIGH BUILDING IN
AND WIND CHILLS WILL LIKELY NOT REACH 25 BELOW. BY SUNRISE A
RETURN FLOW COULD PRODUCE A 3-5 KT WIND AGAIN... SO WILL MAINTAIN
THE WIND CHILL ADVISORY IN MOST AREAS AND SIMPLY TRIM THE ADVISORY
WHERE CLOUDS HAVE ARRIVED. MOISTURE WITH THE NEXT SFC-MID LEVEL
TROUGH SPREADS SOUTHEAST ACROSS THE FORECAST AREA ON WEDNESDAY. WHAT
LOWER LEVEL THERMO-DYNAMIC FORCING THERE IS MOSTLY MOVES ACROSS
THE AREA BEFORE THE DEEPER MOISTURE ARRIVES. MODELS SHOW THE
COLUMN SATURATES TO AT LEAST 700MB THRU THU AFTERNOON/EVENING WITH
AND AHEAD OF THE PASSING SFC-MID LEVEL TROUGH AXIS. MODEL
CONSENSUS DOES HAVE SOME 500-300MB PV ADVECTION MOVING ACROSS THE
AREA CENTERED ON 00Z THU ALONG WITH SOME WEAK 700-500MB QG
CONVERGENCE. GIVEN THE MOISTURE SIGNAL...THE WEAK QG
CONVERGENCE...RATHER DEEP CYCLONIC FLOW FOR CONVERGENCE AND SOME
PV ADVECTION/DIVERGENCE ALOFT...MAINTAINED TREND OF VERY LIGHT
SNOW LIKELY. SNOW AMOUNTS FROM THIS SYSTEM STILL LOOK LIKE A
DUSTING UP TO ONE INCH. WITH SOME SFC-700MB MOISTURE AND CYCLONIC
FLOW/CONVERGENCE LINGERING LATER WED NIGHT...ADDED MENTION OF SCT
FLURRIES TO 06Z-12Z THU FCST GRIDS. Q-VECTOR DIVERGENCE SPREADS
ACROSS THE AREA THURSDAY. LOWER LEVEL COLD ADVECTION WED NIGHT/MUCH
OF THU SENDS 925MB TEMPS BACK INTO THE -11C TO -14C RANGE FOR THU
AFTERNOON. TEMPS LOOKING TO END UP NEARLY STEADY ON THU. WITH THE
MORE PROGRESSIVE TROUGH AND MID LEVEL RIDGING BUILDING EAST INTO
THE UPPER MIDWEST...STRONG 925-850MB WARM ADVECTION SPREADS
ACROSS MN/IA/WI THU NIGHT.
IN THE EXTENDED...THE CONUS REMAINS IN A SPLIT-FLOW PATTERN ALOFT.
THE PRIMARY SHORTWAVE ENERGY EMBEDDED WITHIN THE MILDER NORTHERN
STREAM MIGRATES ACROSS SOUTHERN CANADA...EXITING THE NORTH
AMERICAN CONTINENT BETWEEN 45-50N LATITUDE AND OCCASIONALLY MIXING
WITH AN ARCTIC BOUNDARY IN PLACE. THE OPERATIONAL GFS/ECMWF
GENERALLY HANDLE THE INDIVIDUAL WAVES ALONG THE US/CANADIAN BORDER
WITH LITTLE EXCITEMENT. AT LEAST THROUGH THE WEEKEND...A BLEND OF
THE THE GFS/EC OFFER GUIDANCE FOR A GRADUAL WARMUP WORKING WEST-
TO-EAST ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI.
&&
.AVIATION.../06Z TAF ISSUANCE/
CANADIAN HIGH PRESSURE CENTERED OVER SOUTHERN MINNESOTA HAS LED TO
CLEAR SKIES AND NEARLY CALM WINDS ACROSS ALL THE TAF SITES LATE
THIS EVENING. WIDESPREAD MVFR STRATUS ON THE BACK SIDE OF THE
RIDGE OVER THE DAKOTAS HAS BEEN INCHING EASTWARD INTO SWRN MN
DURING THE PAST COUPLE OF HOURS. MODELS REMAIN AT ODDS WITH THE
EVOLUTION OF THIS STRATUS WITH SOME SHOWING IT REMAINING TO THE
WEST AND OTHERS SHOWING IT BUILDING EASTWARD OVERNIGHT AND TUESDAY
BEHIND THE RIDGE. WILL SIDE WITH THE PREVIOUS FORECAST AND BUILD
IT EASTWARD THROUGH THE PERIOD GIVEN THE GOOD REPRESENTATION OF
CURRENT CLOUD COVER THOSE MODELS HAVE AT THE PRESENT TIME.
KMSP...BIGGEST CONCERNS WILL BE WHETHER THE STRATUS TO THE WEST CAN
MAKE IT AS FAR EAST AS MSP AND WHEN IT WOULD ARRIVE. SIMPLE
EXTRAPOLATION OF CURRENT TRENDS WOULDN/T BRING THE CLOUDS IN
UNTIL TUESDAY EVENING. HOWEVER...THINK EASTWARD EXPANSION WILL
ACCELERATE AS THE RIDGE PUSHES TO THE SOUTH SO FAVORED TIMING OF
THE PREVIOUS FORECAST AND OF THE RAP MODEL. FORECAST SOUNDINGS
SHOW GOOD SATURATION BETWEEN 020-030...SO INTRODUCED MVFR CIGS FOR
TUESDAY AFTERNOON INTO EVENING.
/OUTLOOK FOR KMSP/
WED...MVFR CONDITIONS/-SN POSSIBLE. WSW WINDS 4 TO 8 KTS.
THU...MVFR CEILINGS/FLURRIES POSSIBLE. NW WINDS 8 TO 12 KTS.
FRI...VFR. WINDS SW 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR BENTON-BLUE
EARTH-BROWN-CHIPPEWA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-
ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-
MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-REDWOOD-
RENVILLE-RICE-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-
TODD-WASECA-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
CLF/BB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
608 AM EST TUE JAN 1 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION ON TUESDAY...BRINGING
AN END TO PRECIPITATION. HIGH PRESSURE WILL MOVE IN FOR
WEDNESDAY...WITH A WEAK DISTURBANCE PASSING NORTH OF THE REGION
THURSDAY AND THURSDAY NIGHT. ANOTHER AREA OF HIGH PRESSURE WILL
MOVE OVER THE OHIO VALLEY ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE PRIMARY FORECAST CONCERN FOR TODAY WILL BE THE CHANCES OF
DRIZZLE / FREEZING DRIZZLE THIS MORNING.
MEASURABLE PRECIPITATION HAS ALL BUT ENDED FOR THE CWA...WITH THE
MAJORITY OF THE FORCING AND DEEP MOISTURE PUSHING OFF TO THE EAST.
HOWEVER...THE RADAR SCREENS HAVE FILLED IN WITH VERY LIGHT ECHOES
(NOT JUST ON KILN...BUT ALSO ON KIND AND THE NEARBY TDWR SITES).
RECENT HRRR RUNS HAVE ALSO DEPICTED PATCHY-LOOKING LIGHT ECHOES IN
SIMULATED REFLECTIVITY. BASED ON SURFACE OBSERVATIONS...THESE
ECHOES ARE AN INDICATION OF A MIXTURE OF FLURRIES AND DRIZZLE. THE
GRIDS WILL THUS TRANSITION QUICKLY THIS MORNING FROM SNOW TO A
FLURRY/DZ OR FLURRY/FZDZ MIX.
ONE OF THE BIGGEST CHALLENGES IN FORECASTING DZ/FZDZ IS CERTAINLY
PRESENTING ITSELF THIS MORNING...AS THERE IS QUITE A BIT OF
UNCERTAINTY IN WHETHER OR NOT THERE IS ENOUGH MOISTURE AT TEMPS
COLDER THAN -10C TO SUPPORT THE PRODUCTION OF ICE CRYSTALS.
MODEL SOUNDINGS SHOW A RAPID DRYING ABOVE 700MB. RAP/NAM RH PLOTS
AT -10C SHOW A RATHER EXTREME DRY PUNCH MOVING ENE OUT OF SOUTHERN
INDIANA...WITH RH VALUES BELOW 5 PERCENT. DESPITE THIS...MANY OF
THE OBSERVATIONS ARE KEEPING -SN AS THE PREVAILING WEATHER TYPE.
BASED ON EYEWITNESS OBSERVATIONS AT NWS ILN...CURRENT
PRECIPITATION IS IN THE FORM OF VERY SMALL CRYSTALS (STILL
ICE...BUT NOT A TYPICAL SNOWFLAKE).
GIVEN THE EXTREMELY WEAK ASCENT...TEMPERATURES VERY CLOSE TO
FREEZING...AND APPARENT MIXING WITH SNOW...NO SIGNIFICANT IMPACTS
FROM FZDZ ARE EXPECTED THIS MORNING.
DESPITE THE DRYING ALOFT...THE LOW LEVEL MOISTURE IS FORECAST TO
REMAIN THICK THROUGH THE DAY...WITH NOWHERE TO GO UNDER AN
INVERSION. ANY EROSION TO THE CLOUD BASE WILL COME LATE IN THE DAY
OR TONIGHT. WITH COLD ADVECTION KICKING IN BEHIND THE SURFACE
FRONT...AND LITTLE TO NOTHING IN THE WAY OF
INSOLATION...TEMPERATURES WILL GO ALMOST NOWHERE TODAY FROM THE
CURRENT VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
MID-LEVEL FLOW WILL REMAIN QUASI-ZONAL OVER THE OHIO VALLEY
THROUGH THE END OF THE WEEK. AT THE SURFACE...HIGH PRESSURE WILL
BEGIN NUDGING INTO THE OHIO VALLEY FROM THE SOUTHWEST TONIGHT.
THIS NARROW RIDGE WILL BE SHUNTED A BIT TO THE SOUTHEAST AS A
STACKED TROUGH (AND EVENTUAL SURFACE LOW) PASSES THROUGH THE GREAT
LAKES ON THURSDAY. AFTER THE TROUGH AXIS CLEARS THE OHIO VALLEY
THURSDAY NIGHT...A MUCH STRONGER AND LARGER HIGH WILL BEGIN TO
ESTABLISH ITSELF ON FRIDAY.
WITH THE CHILLY STARTING POINT AND GRADUALLY CLEARING SKIES...NOT
TO MENTION THE SNOW PACK OVER THE REGION...SINGLE DIGIT TEMPS
ARE BEING FORECAST FOR THE NORTHWESTERN CWA TONIGHT. ON
WEDNESDAY...VERY LITTLE MIXING WILL OCCUR UNDER AN INVERSION...AND
THE AXIS OF COLDEST 925MB TEMPS WILL ALSO BE PASSING THROUGH THE
CWA. THROUGH BOTH OF THESE PERIODS...THE FORECAST IS GENERALLY
LOWER THAN MODEL GUIDANCE. THE EXCEPTION TO THIS IS THE ECMWF FOR
LOWS TONIGHT...WHICH IS GOING AS LOW AS 1 DEGREE IN DARKE COUNTY.
THE COLD PATTERN WILL CONTINUE THROUGH THE WEEK...WITH ANOTHER
SHOT OF COLD ADVECTION KICKING IN WITH THE SHORTWAVE ON THURSDAY.
A SLIGHT CHANCE OF LIGHT SNOW HAS BEEN KEPT IN THE FORECAST FOR
THURSDAY EVENING...GENERALLY FOR AREAS NORTH OF I-70. AN ARGUMENT
COULD BE MADE THAT ONLY FLURRIES WILL BE EXPERIENCED THIS FAR
SOUTH...SO THIS IS FAR FROM A CERTAINTY OR ANYTHING THAT WILL
CAUSE MUCH OF AN IMPACT.
LITTLE CHANGE IS EXPECTED FOR FRIDAY...WITH THE CWA AT THE
NORTHEAST PERIPHERY OF THE SURFACE HIGH...AND STILL FAR AWAY FROM
ANY LEGITIMATE WARM ADVECTION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THE 12Z ECMWF...GFS AND CMC ARE ALL IN DECENT AGREEMENT WITH SHORT
WAVE ENERGY DROPPING DOWN ACROSS THE LOWER GREAT LAKES THURSDAY
AFTERNOON INTO FRIDAY MORNING. THE BEST FORCING ASSOCIATED WITH THIS
WILL REMAIN OFF TO OUR NORTH AND EAST...BUT THINK A FEW FLURRIES OR
LIGHT SNOW SHOWERS WILL BE POSSIBLE AT LEAST ACROSS OUR NORTHEASTERN
AREAS...PRIMARILY THURSDAY NIGHT. TEMPERATURES WILL REMAIN
SEASONABLY COLD TO START THE LONG TERM PERIOD. WITH A LITTLE BIT OF
REINFORCING COLD AIR BEHIND THE SHORT WAVE...WILL GO A COUPLE OF
DEGREES COOLER FOR HIGHS FRIDAY COMPARED TO THURSDAY.
WE WILL TRANSITION INTO MORE OF A WESTERLY FLOW PATTERN THROUGH THE
WEEKEND...ALLOWING FOR A MODERATION IN TEMPERATURES SATURDAY THROUGH
MONDAY. BY THE END OF THE PERIOD...EXPECT HIGHS TO BE NEAR OR EVEN A
LITTLE ABOVE NORMAL FOR THIS TIME OF YEAR. THE GFS AND ECMWF ARE
BOTH SHOWING A FAIRLY PROGRESSIVE SHORT WAVE WORKING ACROSS THE
REGION SATURDAY NIGHT INTO SUNDAY. WE MAY EVENTUALLY NEED SOME LOW
POPS WITH THIS FEATURE...BUT MOISTURE APPEARS LIMITED SO WILL
MAINTAIN A DRY FORECAST AT THIS POINT.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
A COLD FRONT WILL MOVE SLOWLY SOUTHEAST ACROSS THE TAF SITES THIS
MORNING. FORECAST DILEMMA THIS MORNING HAS BEEN WHETHER TO INCLUDE
DRIZZLE/FREEZING DRIZZLE IN THE TAFS. THE MODELS HAVE NOT HANDLED
THE CURRENT PCPN DEVELOPMENT ACRS THE TAF SITES EALRY THIS
MORNING. THEY HAD BEEN ADVERTISING THE POTENTIAL FOR DRIZZLE/FREEZING
DRIZZLE BASED ON SURFACE TEMPERATURES...BUT SINCE STRONGER ECHOES
ARE SHOWING UP ON THE RADAR...AND OBSERVATIONS ARE REPORTING
SNOW...THE DRIZZLE/FREEZING DRIZZLE HAS BEEN HARD TO COME BY (SANS
KCVG). CURRENT PCPN LOOKS TO MOVE OUT FAIRLY SOON SO WILL MAKE A
LAST MINUTE DECISION ON HOW LONG TO KEEP PCPN AT ANY GIVEN TAF
SITE.
OTHERWISE...FOR THIS AFTERNOON...DRIER AIR WILL BRING VSBYS BACK TO
VFR...BUT LOW LEVEL MOISTURE WILL REMAIN WITH CIGS MVFR. HIGH
PRESSURE WILL BEGIN TO BUILD INTO THE REGION TONIGHT AND ESTABLISH
ITSELF OVER THE REGION ON TUESDAY. THIS WILL ALLOW LOW LEVEL
MOISTURE TO EVENTUALLY SCOUR OUT/ERODE OVER THE AREA.
OUTLOOK...MVFR CEILINGS POSSIBLE THURSDAY INTO FRIDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...JGL
AVIATION...HICKMAN
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
949 AM CST TUE JAN 1 2013
.UPDATE...
AN UPPER LEVEL TROUGH CURRENTLY OVER THE TEXAS PANHANDLE IS
INDUCING ENOUGH LIFT FOR SPRINKLES AND LIGHT RAIN TO DEVELOP
ACROSS PARTS OF THE REGION. WITH DRIER AIR CONTINUING TO WORK IN
FROM THE NORTH AND NORTHWEST...THE REMAINING PRECIP HAS NOW
SHIFTED EAST OF A LINE FROM SHERMAN TO DALLAS TO TEMPLE. EXPECT
THE SCATTERED LIGHT PRECIPITATION TO CONTINUE THIS MORNING WITH
A SLIGHT CHANCE FOR LIGHT RAIN OVER THE EASTERN AND SOUTHEASTERN
COUNTIES THIS AFTERNOON. EARLIER THIS MORNING...WE RECEIVED A FEW
REPORTS OF VERY BRIEF AND LIGHT SLEET PELLETS FALLING WITH THE
RAIN. THIS WILL ALSO BE POSSIBLE THROUGH THE MORNING HOURS.
THE MAIN CHALLENGE FOR TODAY IS THE CLOUD COVER AND ITS EFFECTS ON
TEMPERATURES. SHORT TERM MODELS SUCH AS THE RAP AND TEXAS TECH WRF
SUGGEST PARTS /IF NOT ALL/ OF THE REGION WILL REMAIN SOCKED IN LOW
CLOUDS FOR MUCH OF THE DAY...BUT THE MAIN DIAGNOSTIC MODELS WANT
TO SCATTER MUCH OF THE REGION OUT THIS AFTERNOON...EXCEPT FOR
MAYBE THE NORTHEASTERN COUNTIES. WITH THE UPPER LEVEL TROUGH
SWINGING ACROSS OKLAHOMA TODAY AND NORTH TO NORTHWEST FLOW THROUGH
THE MID LEVELS OF THE ATMOSPHERE...THIS IS OFTEN A SITUATION WHERE
CLOUDS DO REMAIN AROUND FOR MUCH OF THE DAY AND TEMPERATURES STAY
MUCH COOLER. HIGH CLOUDS STREAMING OVER THE AREA SHOULD ALSO WORK
AGAINST EROSION OF THE LOWER LEVEL CLOUDS...BUT THE HIGH CLOUDS
MAY SHIFT EAST THIS AFTERNOON AS THE UPPER LEVEL TROUGH CONTINUES
MOVING EAST. EVEN THOUGH CONFIDENCE IN THIS SCENARIO IS NOT VERY
HIGH DUE TO UNCERTAINTY ON IF AND WHERE THE CLOUDS WILL
BREAK...HAVE DECIDED TO ADJUST THE SKIES TO MOSTLY CLOUDY AND
CLOUDY FOR THE REMAINDER OF THE DAY. ALSO...ADJUSTED HIGH
TEMPERATURES NORTH OF I-20 DOWN A FEW DEGREES BUT DID NOT
ADJUST TEMPERATURES ELSEWHERE. OVERALL..THE FORECAST CALLS FOR A
WARM-UP OF ABOUT 5 DEGREES FROM CURRENT TEMPERATURES...EXCEPT IN
THE WEST WHERE THINNING CLOUDS THIS AFTERNOON MAY ALLOW TEMPS TO
WARM ANOTHER 5-10 DEGREES.
82/JLD
&&
.AVIATION...
UPPER TROUGHING CONTINUES ACROSS THE CENTRAL AND SOUTHWESTERN
CONUS TODAY PROVIDING SOUTHWEST FLOW ALOFT ACROSS NORTH TEXAS.
MEANWHILE A BROAD AREA OF MID LEVEL CLOUDS WITH OCCASIONAL
SPRINKLES WAS BEING GENERATED BY A SHORTWAVE LIFTING NORTHEAST
ACROSS WEST TEXAS...AND PRECIPITATION MAY OCCASIONALLY REDUCE
VISIBILITIES TO 5-6SM BEFORE MOVING EAST OF THE REGION LATER THIS
MORNING. WILL LIKELY STICK WITH AT LEAST A TEMPO FOR LIGHT RAIN
AND BR AT ALL LOCATIONS UNTIL 15Z. HEAVIER PRECIPITATION SHOULD
REMAIN SOUTH OF TAF LOCATIONS WHERE DEEPER MOISTURE RESIDES. WINDS
HAVE BECOME NORTH TO NORTHWEST AND SHOULD REMAIN AS SUCH...WITH
SPEEDS GENERALLY 10-15 KT.
CEILINGS ARE MORE OF A CHALLENGE TODAY AS CLOUD DECKS HAVE BEEN
ALL OVER THE PLACE DURING THE PAST 12 HOURS. CONDITIONS HAVE
SHOWN A GENERAL IMPROVING TREND THIS MORNING DUE TO COOLER DRIER
AIR PUSHING IN FROM THE NORTH BEHIND A COLD FRONT. HOWEVER...WITH
LIGHT PRECIP AND VARYING CIGS...TAF SITES WILL MOST LIKELY
EXPERIENCE PERIODS OF MVFR DECKS THROUGH THE LATE MORNING HOURS.
WILL NEED TO KEEP AN EYE ON THE AREA OF IFR CIGS OVER NORTHWESTERN
COUNTIES...BUT AT THIS TIME FEEL IT WILL REMAIN FAIRLY ISOLATED TO
THAT REGION. OTHERWISE WILL PLAN ON STICKING SOMEWHAT CLOSE TO
GUIDANCE WITH RESPECT TO CONDITIONS IMPROVING TO VFR THIS
AFTERNOON AS THE SHORTWAVE SHIFTS EAST OF THE REGION.
30
&&
.PREV UPDATE...
.UPDATE...
AREA OBS INDICATING THAT A FEW SPRINKLES MAY BE REACHING THE
SURFACE THIS PAST HOUR...SO HAVE ADDED THAT WEATHER ELEMENT TO THE
FORECAST FOR NORTHERN COUNTIES THROUGH MID MORNING...OR UNTIL THE
RICHER SW FEED OF MID LEVEL MOISTURE SHIFTS FURTHER TO THE EAST.
05/
&&
.PREV DISCUSSION... /ISSUED 329 AM CST TUE JAN 1 2013/
POSITIVE-TILTED LONGWAVE TROUGH CONTINUES FROM ROCKIES INTO THE
MISSISSIPPI VALLEY ALOFT. ONE SHORTWAVE WAS ROTATING NORTHEAST OUT
OF NEW MEXICO WITH ANOTHER DROPPING SOUTH THROUGH WYOMING AND INTO
COLORADO AND KANSAS. AT THE SURFACE...A WEAK FRONTAL WAVE WAS DRAPED
NEAR THE I-10 CORRIDOR WITH A WEAK SURFACE LOW ACROSS SOUTH TEXAS.
DRIER AIR WAS SLOWLY FILTERING ACROSS THE RED RIVER VALLEY INTO
AREAS NORTH OF I-20.
SHORT TERM FORECAST IS A BIT TRICKY THIS MORNING WITH COLD AIRMASS
ONLY 1000-2000 FT DEEP ACROSS NORTH TEXAS...MORE SHALLOW THE
FURTHER SOUTH OF I-20 YOU GO. PATCHY DENSE FOG AND DRIZZLE WAS
OCCURRING WITHIN THE MORE SHALLOW COOL AIRMASS SOUTH OF THE
I-20/30 CORRIDORS. ALSO...WEAK ISENTROPIC ASCENT WAS RESULTING IN
SCATTERED AREAS OF VERY LIGHT RAIN ACROSS OUR CENTRAL TEXAS COUNTIES.
WE EXPECT THE PATCHY DENSE FOG/RAIN/ DRIZZLE TO CONTINUE MAINLY
SOUTH OF A GREENVILLE/SULPHUR SPRINGS-GRANBURY-COMANCHE LINE THROUGH
MID-LATE MORNING. THIS WILL NOT INCLUDE THE DFW METRO AND POINTS
NORTH...PER AFOREMENTIONED DRIER AIR FILTERING SOUTH OUT OF OKLAHOMA
WITH DEEPER MIXING TO OCCUR. MID-HIGH LEVEL RETURNS HAVE BEEN
INCREASING ON REGIONAL RADAR AND WITHIN THE STRONG SOUTHWEST FLOW
ALOFT ACROSS THE NORTHWEST COUNTIES... BUT ANY LIGHT PRECIPITATION
THAT WOULD FALL FROM THESE HIGH DECKS WILL LIKELY EVAPORATE WELL
BEFORE REACHING THE SHALLOW AND SATURATED FRONTAL INVERSION BELOW
WITH VERY DRY AIR NOTED ON 00Z FWD SOUNDING JUST ABOVE THE FRONTAL
INVERSION. WILL NOT INSERT POPS AT THIS TIME...BUT WILL MONITOR
OBSERVATIONS CAREFULLY AS TEMPERATURES FALL INTO THE MID- UPPER
30S ACROSS THESE AREAS BY SUNRISE.
EXPECT RAIN CHANCES TO END ACROSS THE CENTRAL TEXAS AND FAR SOUTHEAST
COUNTIES BY AFTERNOON...AS THE SHORTWAVE OVER NEW MEXICO TRACKS
EAST ACROSS OKLAHOMA AND THE SURFACE WAVE TO OUR SOUTH HEADS INTO
THE NORTHERN GULF OF MEXICO. WITH THE ENSUING SUBSIDENCE...EXPECT
AT LEAST PARTIAL SUNSHINE ACROSS THE WESTERN HALF OF THE AREA THIS
AFTERNOON AND EVENING...WITH CLEARING OVERNIGHT. A SPLIT FLOW
PATTERN DEVELOPS RIGHT ACROSS THE RED RIVER VALLEY AND NORTH TEXAS
BY WEDNESDAY WITH SUBSEQUENT AND SHALLOW SURGES OF POLAR AIR BEING
REINFORCED ACROSS THE CWA. HIGHS WILL BE IN THE 40S WITH 50S IN
THE SOUTH THROUGH THE WEEK WITH THE AREA REMAINING DRY AND LITTLE
PRECIPITATION EXPECTED. TWO PIECES OF SHORTWAVE ENERGY WITHIN BOTH
THE SUBTROPICAL AND POLAR STREAMS MERGE ACROSS NEW MEXICO AND WEST
TEXAS ON LATER THURSDAY INTO FRIDAY NIGHT...BUT IT APPEARS BEST
MOISTURE WILL BE CONFINED WELL SOUTH OF OUR AREA AS THIS
DISTURBANCE LIFTS ACROSS THE AREA. NO RAIN IS EXPECTED WITH ONLY
INCREASING CLOUDINESS DURING THIS PERIOD.
MEDIUM RANGE MODELS KEEP IT DRY AND SEASONABLE BY THE WEEKEND...THEN
LOSE TOUCH WITH EACH OTHER ON SOLUTION HEADING INTO EARLY NEXT
WEEK. WE HAVE MAINTAINED A DRY FORECAST FOR THE NEXT WEEK AND
BEYOND.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 45 28 45 29 48 / 10 5 5 5 5
WACO, TX 51 30 46 30 49 / 40 5 5 5 10
PARIS, TX 43 27 43 27 46 / 20 5 5 5 5
DENTON, TX 44 25 45 26 47 / 10 5 5 5 5
MCKINNEY, TX 43 24 44 27 46 / 10 5 5 5 5
DALLAS, TX 46 29 46 29 49 / 10 5 5 5 5
TERRELL, TX 47 29 44 28 49 / 20 5 5 5 5
CORSICANA, TX 49 30 46 30 50 / 40 5 5 5 10
TEMPLE, TX 53 31 47 31 50 / 50 5 5 5 10
MINERAL WELLS, TX 42 23 45 26 47 / 10 5 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
75/82
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
529 AM CST TUE JAN 1 2013
.UPDATE...
SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...
MODELS DID NOT INITIALIZE PARTICULARLY WELL THIS MORNING SO
CONFIDENCE IS RATHER LOW. WENT WITH A GFS/RAP BLEND. AREA OF HEAVY
RAIN/TSRA ALONG THE COAST WILL MOVE OFFSHORE IN THE NEXT HOUR OR
SO. THIS WILL LEAVE JUST SOME PATCHY LIGHT RAIN FOR THE NEXT
COUPLE OF HOURS OVER THE REST OF SE TX. THE RAP MASS FIELDS KEEPS
MOST OF THE RAIN AWAY FROM AREA TAF SITES. A PRE-FRONTAL TROUGH IS
APPROACHING THE COAST WITH THE ACTUAL FRONT STILL LAGGING A FEW
HOURS BEHIND. AM EXPECTING WINDS TO SHIFT TO THE NORTH AND
INCREASE THIS MORNING. CIGS ARE THE OTHER ISSUE AND FCST SOUNDINGS
ARE PESSIMISTIC WITH CIGS TODAY. WILL MAINTAIN LIFR CIGS THROUGH
18Z AND THEN SHOW IMPROVEMNT TO VFR CONDS BY MID AFTN. 43
&&
.PREV DISCUSSION... /ISSUED 451 AM CST TUE JAN 1 2013/
DISCUSSION...
IT IS GOOD TO SEE RAIN ON THE RADAR ACROSS SE TX AS WE HEAD INTO
THE NEW YEAR. IT LOOKS LIKE COLLEGE STATION MAY BE THE ONLY
CLIMATE SITE WITH ABOVE NORMAL PRECIPITATION FOR THE YEAR WITH
HOUSTON IAH...HOUSTON HOU AND GALVESTON ALL SHOWING RAINFALL
DEFICITS TO END THE YEAR. THE OTHER CLIMATE NOTE IS THAT 2012
SHOULD GO DOWN AS THE WARMEST YEAR ON RECORD FOR HOUSTON. SEE MORE
DETAILS IN THE CLIMATE SECTION.
CURRENTLY HAVE A LINE OF SHOWERS AND THUNDERSTORMS FROM SW LA
INTO SE TX AND ALONG THE UPPER TX COAST. MOST OF THE HEAVY
RAINFALL SHOULD BE CONCENTRATED RIGHT ALONG THE IMMEDIATE COAST
INCLUDING GALVESTON IS AND BOLIVAR. THIS ACTIVITY SHOULD SLOWLY
MOVE EAST. A COLD FRONT IS SLOWLY PUSHING INTO THE AREA WITH A
PRE-FRONTAL TROUGH STALLED ACROSS THE HOUSTON AREA. BROAD UPPER
LEVEL TROUGH REMAINS OVER THE DESERT SW WITH SW JET FLOW FROM BIG
BEND OF TX TO THE OHIO RIVER VALLEY. RIGHT REAR QUAD OF UPPER JET
OR RIGHT ENTRANCE REGION SHOULD MOVE OVER TX TODAY AND WED BASED
ON SHORT RANGE MODELS. OVERALL THE SET UP IS FAVORABLE FOR RAIN OR
ELEVATED SHOWERS. DRIER AIR SHOULD MVOE INTO THE AREA LATER TODAY
AND TONIGHT WHICH SHOULD KEEP PRECIP CHANCES CONFINED TO THE
SOUTHERN HALF OF THE FORECAT AND THE COASTAL WATERS. BASED ON 00Z
MODEL SUITE THINK MAJORITY OF RAINFALL WILL REMAIN OFF THE COAST
SO TAILORED POPS CLOSER TO THAT THINKING. THIS MEANS KEEPING 20/30
POPS IN THE FORECAST ALONG THE COAST THROUGH MID WEEK.
WITH JET FLOW REMAINING SW THROUGH THE END OF THE WEEK...LIKELY
HAVE MOSTLY CLOUDY CONDITIONS WHICH WITH COOLER AIRMASS WILL KEEP
TEMPS A GOOD 5 DEGREES BELOW NORMAL. DECIDED TO SHIFT SOME 20 POPS
INTO FRI NIGHT AND SAT MORNING. GFS SHOWS ANOTHER SHORTWAVE TROUGH
PUSHING PAST THE AREA DURING THIS TIME WITH THE ECMWF SLOWER.
SPLIT THE DIFFERENCES A BIT WITH THE TIMING OF THE DISTRURBANCE
BUT WHILE THERE MAY BE LARGE SCALE ASCENT FOR PRECIP...NOT SURE
HOW MUCH MOISTURE WILL BE AVAILABLE. HIGH PRESSURE SHOULD BUILD
INTO THE AREA AGAIN OVER THE WEEKEND. OVERALL EXPECT TEMPS TO
CREEP UP TO NORMAL LEVELS FOR THE WEEKEND AND EARLY NEXT WEEK.
SOUTHERLY RETURN FLOW AND INCREASED GULF MOISTURE IS NOT EXPECTED
TO OCCUR UNTIL NEXT TUE.
39
MARINE...
A PRE-FRONTAL TROUGH AND ASSOCIATED WIND SHIFT WAS APPROACHING THE
COAST. A COLD FRONT LAGGED BEHIND...AND AT 2 AM THE FRONT EXTENDED
FROM LUFKIN TO COLLEGE STATION. THE FRONT WILL CONTINUE TO SAG SOUTH
AND THIS FEATURE SHOULD CROSS THE COAST BETWEEN 11-13Z. WINDS WILL
QUICKLY SHIFT TO THE NORTH AND INCREASE TO GREATER THAN 20 KNOTS
OVER THE GULF. AN SCA WILL REMAIN IN EFFECT FOR THE GULF WATERS
THROUGH 21Z AND WILL LIKELY BE EXTENDED LONGER WITH THE AFTN UPDATE.
AN SCEC WILL BE REQUIRED FOR THE BAYS TODAY. STRONG WINDS ARE
EXPECTED FOR MOST OF THE WEEK AND SCA/SCEC FLAGS WILL BE NEEDED FOR
MUCH OF THE WEEK AHEAD. TIDES ARE ABOVE NORMAL BUT OFFSHORE WINDS
WILL LOWER TIDE LEVELS BY AFTERNOON AND TIDE LEVELS WILL REMAIN
BELOW NORMAL ON THURSDAY. 43
CLIMATE...
NO BIG SURPRISE WITH REGARD TO TEMPERATURES. DECEMBER 2012 WAS
VERY WARM...AVERAGING 3 TO 5 DEGREES WARMER THAN THE 30 YEAR
NORMALS. 2012 WILL ALSO HAVE THE DISTINCTION OF BEING THE WARMEST
YEAR ON RECORD FOR THE CITY OF HOUSTON. THE UNOFFICIAL 2012
AVERAGE TEMPERATURE FOR THE CITY OF HOUSTON WAS 72.1 DEGREES. THE
PREVIOUS WARMEST YEAR ON RECORD WAS 71.9 DEGREES IN 1962.
FWIW...THE AVERAGE TEMPERATURE IN 2011 WAS 71.8 DEGREES WHICH WAS
THE THIRD WARMEST YEAR ON RECORD.
COLLEGE STATION HAD AN AVERAGE TEMPERATURE IN 2012 OF 71.6 DEGREES
WHICH TIES LAST YEAR FOR THE WARMEST YEAR ON RECORD.
THE CITY OF GALVESTON ALSO RECORDED IT`S WARMEST YEAR ON RECORD WITH
AN AVERAGE TEMP OF 73.9 DEGREES. THE PREVIOUS WARMEST YEAR WAS 72.6
DEGREES BACK IN 2006. THE SIX WAMREST YEARS ON RECORD FOR GALVESTON
HAVE OCCURRED SINCE 1994.
HOBBY AIRPORT ALSO RECORDED IT`S WARMEST YEAR ON RECORD. THE AVERAGE
ANNUAL TEMP WAS 72.6 DEGREES BESTING LAST YEARS RECORD VALU OF 72.4
DEGREES. THE EIGHT WARMEST YEARS ON RECORD HAVE OCCURRED SINCE 1998.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 55 36 49 34 52 / 50 10 10 10 10
HOUSTON (IAH) 59 41 50 37 54 / 80 20 10 10 10
GALVESTON (GLS) 64 46 51 43 53 / 90 30 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 PM CST THIS
AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...
MATAGORDA BAY.
SMALL CRAFT ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1229 PM CST TUE JAN 1 2013
.DISCUSSION...
PLEASE SEE 18Z AVN DISCUSSION...
&&
.AVIATION...
CIGS IN THE HOUSTON METRO AREA HAVE IMPROVED TO VFR THIS
AFTERNOON...HOWEVER THIS IMPROVEMENT IS NOT LIKELY TO EXTEND
FURTHER INLAND TO UTS OR CXO. MVFR CONDITIONS ARE LIKELY TO
PERSIST AT THE COASTAL COASTAL TERMINALS AS THEY REMAIN ON THE
BACK EDGE OF A LARGE RAIN SHIELD EXTENDING OFF SHORE.
ALL TERMINALS WILL LIKELY BE MVFR AFTER 01Z THIS EVENING. VFR
CONDITIONS ARE POSSIBLE IN THE HOUSTON TERMINALS BY MID-MORNING
WEDNESDAY. MVFR CONDITIONS SHOULD PERSIST AT OTHER TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 1012 AM CST TUE JAN 1 2013/
DISCUSSION...
HEAVIER PRECIP HAS SHIFTED OFFSHORE AND IS ALONG THE COLD FRONT
OVER THE COASTAL WATERS OUT BEYOND 20NM. THE FRONT SHOULD CONTINUE
TO MOVE SOUTHEAST THOUGH SLOWLY. PATCHY LIGHT RAIN WILL CONTINUE
THIS MORNING MAINLY OVER THE SOUTHERN HALF OF THE AREA INTO THE
EARLY AFTERNOON. AS LIFT WITH APPROACHING SHORTWAVE OVER THE HILL
COUNTRY NEARS EXPECT THE PRECIP TO SHIFT EAST AND LIGHTEN.
OVERCAST SKIES WILL PREVAIL THROUGH THE AFTERNOON HOURS BUT MAY
BECOME BROKEN THIS EVENING IN THE NORTHWESTERN AREAS WITH MAINLY
HIGH CLOUDS. THE LIGHT PRECIP AND COLD AIR ADVECTION SHOULD KEEP
TEMPERATURES IN THE MID 40S TO MID 50S WITH NEAR STEADY
TEMPERATURES. WILL LIKELY DO AN UPDATE AROUND 1130 OR NOON TO
CLEAR OUT PRECIP IN THE WEST AND NORTHWEST.
AS OF 1005 AM THIS MORNING GALVESTON HAS HAD A RECORD SETTING 3.99"
OF RAIN AND IS STILL FALLING THOUGH LIGHTER NOW.
45
PREV DISCUSSION... /ISSUED 529 AM CST TUE JAN 1 2013/
UPDATE...
SEE 12Z AVIATION DISCUSSION.
AVIATION...
MODELS DID NOT INITIALIZE PARTICULARLY WELL THIS MORNING SO
CONFIDENCE IS RATHER LOW. WENT WITH A GFS/RAP BLEND. AREA OF HEAVY
RAIN/TSRA ALONG THE COAST WILL MOVE OFFSHORE IN THE NEXT HOUR OR
SO. THIS WILL LEAVE JUST SOME PATCHY LIGHT RAIN FOR THE NEXT
COUPLE OF HOURS OVER THE REST OF SE TX. THE RAP MASS FIELDS KEEPS
MOST OF THE RAIN AWAY FROM AREA TAF SITES. A PRE-FRONTAL TROUGH IS
APPROACHING THE COAST WITH THE ACTUAL FRONT STILL LAGGING A FEW
HOURS BEHIND. AM EXPECTING WINDS TO SHIFT TO THE NORTH AND
INCREASE THIS MORNING. CIGS ARE THE OTHER ISSUE AND FCST SOUNDINGS
ARE PESSIMISTIC WITH CIGS TODAY. WILL MAINTAIN LIFR CIGS THROUGH
18Z AND THEN SHOW IMPROVEMENT TO VFR CONDS BY MID AFTN. 43
PREV DISCUSSION... /ISSUED 451 AM CST TUE JAN 1 2013/
DISCUSSION...
IT IS GOOD TO SEE RAIN ON THE RADAR ACROSS SE TX AS WE HEAD INTO
THE NEW YEAR. IT LOOKS LIKE COLLEGE STATION MAY BE THE ONLY
CLIMATE SITE WITH ABOVE NORMAL PRECIPITATION FOR THE YEAR WITH
HOUSTON IAH...HOUSTON HOU AND GALVESTON ALL SHOWING RAINFALL
DEFICITS TO END THE YEAR. THE OTHER CLIMATE NOTE IS THAT 2012
SHOULD GO DOWN AS THE WARMEST YEAR ON RECORD FOR HOUSTON. SEE MORE
DETAILS IN THE CLIMATE SECTION.
CURRENTLY HAVE A LINE OF SHOWERS AND THUNDERSTORMS FROM SW LA
INTO SE TX AND ALONG THE UPPER TX COAST. MOST OF THE HEAVY
RAINFALL SHOULD BE CONCENTRATED RIGHT ALONG THE IMMEDIATE COAST
INCLUDING GALVESTON IS AND BOLIVAR. THIS ACTIVITY SHOULD SLOWLY
MOVE EAST. A COLD FRONT IS SLOWLY PUSHING INTO THE AREA WITH A
PRE-FRONTAL TROUGH STALLED ACROSS THE HOUSTON AREA. BROAD UPPER
LEVEL TROUGH REMAINS OVER THE DESERT SW WITH SW JET FLOW FROM BIG
BEND OF TX TO THE OHIO RIVER VALLEY. RIGHT REAR QUAD OF UPPER JET
OR RIGHT ENTRANCE REGION SHOULD MOVE OVER TX TODAY AND WED BASED
ON SHORT RANGE MODELS. OVERALL THE SET UP IS FAVORABLE FOR RAIN OR
ELEVATED SHOWERS. DRIER AIR SHOULD MOVE INTO THE AREA LATER TODAY
AND TONIGHT WHICH SHOULD KEEP PRECIP CHANCES CONFINED TO THE
SOUTHERN HALF OF THE FORECAST AREA AND THE COASTAL WATERS. BASED
ON 00Z MODEL SUITE THINK MAJORITY OF RAINFALL WILL REMAIN OFF THE
COAST SO TAILORED POPS CLOSER TO THAT THINKING. THIS MEANS KEEPING
20/30 POPS IN THE FORECAST ALONG THE COAST THROUGH MID WEEK.
WITH JET FLOW REMAINING SW THROUGH THE END OF THE WEEK...LIKELY
HAVE MOSTLY CLOUDY CONDITIONS WHICH WITH COOLER AIRMASS WILL KEEP
TEMPS A GOOD 5 DEGREES BELOW NORMAL. DECIDED TO SHIFT SOME 20 POPS
INTO FRI NIGHT AND SAT MORNING. GFS SHOWS ANOTHER SHORTWAVE TROUGH
PUSHING PAST THE AREA DURING THIS TIME WITH THE ECMWF SLOWER.
SPLIT THE DIFFERENCES A BIT WITH THE TIMING OF THE DISTURBANCEBUT
WHILE THERE MAY BE LARGE SCALE ASCENT FOR PRECIP...NOT SURE HOW
MUCH MOISTURE WILL BE AVAILABLE. HIGH PRESSURE SHOULD BUILD INTO
THE AREA AGAIN OVER THE WEEKEND. OVERALL EXPECT TEMPS TO CREEP UP
TO NORMAL LEVELS FOR THE WEEKEND AND EARLY NEXT WEEK. SOUTHERLY
RETURN FLOW AND INCREASED GULF MOISTURE IS NOT EXPECTED TO OCCUR
UNTIL NEXT TUE.
39
MARINE...
A PRE-FRONTAL TROUGH AND ASSOCIATED WIND SHIFT WAS APPROACHING THE
COAST. A COLD FRONT LAGGED BEHIND...AND AT 2 AM THE FRONT EXTENDED
FROM LUFKIN TO COLLEGE STATION. THE FRONT WILL CONTINUE TO SAG SOUTH
AND THIS FEATURE SHOULD CROSS THE COAST BETWEEN 11-13Z. WINDS WILL
QUICKLY SHIFT TO THE NORTH AND INCREASE TO GREATER THAN 20 KNOTS
OVER THE GULF. AN SCA WILL REMAIN IN EFFECT FOR THE GULF WATERS
THROUGH 21Z AND WILL LIKELY BE EXTENDED LONGER WITH THE AFTN UPDATE.
AN SCEC WILL BE REQUIRED FOR THE BAYS TODAY. STRONG WINDS ARE
EXPECTED FOR MOST OF THE WEEK AND SCA/SCEC FLAGS WILL BE NEEDED FOR
MUCH OF THE WEEK AHEAD. TIDES ARE ABOVE NORMAL BUT OFFSHORE WINDS
WILL LOWER TIDE LEVELS BY AFTERNOON AND TIDE LEVELS WILL REMAIN
BELOW NORMAL ON THURSDAY. 43
CLIMATE...
NO BIG SURPRISE WITH REGARD TO TEMPERATURES. DECEMBER 2012 WAS
VERY WARM...AVERAGING 3 TO 5 DEGREES WARMER THAN THE 30 YEAR
NORMALS. 2012 WILL ALSO HAVE THE DISTINCTION OF BEING THE WARMEST
YEAR ON RECORD FOR THE CITY OF HOUSTON. THE UNOFFICIAL 2012
AVERAGE TEMPERATURE FOR THE CITY OF HOUSTON WAS 72.1 DEGREES. THE
PREVIOUS WARMEST YEAR ON RECORD WAS 71.9 DEGREES IN 1962.
FWIW...THE AVERAGE TEMPERATURE IN 2011 WAS 71.8 DEGREES WHICH WAS
THE THIRD WARMEST YEAR ON RECORD.
COLLEGE STATION HAD AN AVERAGE TEMPERATURE IN 2012 OF 71.6 DEGREES
WHICH TIES LAST YEAR FOR THE WARMEST YEAR ON RECORD.
THE CITY OF GALVESTON ALSO RECORDED IT`S WARMEST YEAR ON RECORD WITH
AN AVERAGE TEMP OF 73.9 DEGREES. THE PREVIOUS WARMEST YEAR WAS 72.6
DEGREES BACK IN 2006. THE SIX WARMEST YEARS ON RECORD FOR
GALVESTON HAVE OCCURRED SINCE 1994.
HOBBY AIRPORT ALSO RECORDED IT`S WARMEST YEAR ON RECORD. THE AVERAGE
ANNUAL TEMP WAS 72.6 DEGREES BESTING LAST YEARS RECORD VALUE OF
72.4 DEGREES. THE EIGHT WARMEST YEARS ON RECORD HAVE OCCURRED
SINCE 1998.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 36 49 34 52 34 / 0 10 10 10 10
HOUSTON (IAH) 41 50 37 54 36 / 10 10 10 10 10
GALVESTON (GLS) 46 51 43 53 42 / 30 20 20 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL MIDNIGHT CST TONIGHT
FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...45
AVIATION/MARINE...44
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1201 PM CST TUE JAN 1 2013
.AVIATION...
MVFR CEILINGS SHOULD CONTINUE THROUGH THE AFTERNOON AS LOW LEVEL
MOISTURE LINGERS BELOW A STRONG INVERSION. THE LOW CLOUDS MAY
SCATTER OUT BRIEFLY LATE THIS AFTERNOON DUE TO MIXING...BUT
SHOULD FILL BACK IN SHORTLY AFTER SUNSET AND LINGER FOR MOST OF
THE NIGHT. DRIER AIR ON THE BACK SIDE OF A DEPARTING SHORT WAVE
SHOULD BRING DECREASING CLOUDS WEDNESDAY MORNING WITH VFR
CONDITIONS EXPECTED AT ALL TAF SITES.
A NORTH TO NORTHWEST WIND WILL PREVAIL THROUGH WEDNESDAY AFTERNOON
AT SPEEDS BETWEEN 8 AND 14 KNOTS.
&&
.UPDATE...
AN UPPER LEVEL TROUGH CURRENTLY OVER THE TEXAS PANHANDLE IS
INDUCING ENOUGH LIFT FOR SPRINKLES AND LIGHT RAIN TO DEVELOP
ACROSS PARTS OF THE REGION. WITH DRIER AIR CONTINUING TO WORK IN
FROM THE NORTH AND NORTHWEST...THE REMAINING PRECIP HAS NOW
SHIFTED EAST OF A LINE FROM SHERMAN TO DALLAS TO TEMPLE. EXPECT
THE SCATTERED LIGHT PRECIPITATION TO CONTINUE THIS MORNING WITH
A SLIGHT CHANCE FOR LIGHT RAIN OVER THE EASTERN AND SOUTHEASTERN
COUNTIES THIS AFTERNOON. EARLIER THIS MORNING...WE RECEIVED A FEW
REPORTS OF VERY BRIEF AND LIGHT SLEET PELLETS FALLING WITH THE
RAIN. THIS WILL ALSO BE POSSIBLE THROUGH THE MORNING HOURS.
THE MAIN CHALLENGE FOR TODAY IS THE CLOUD COVER AND ITS EFFECTS ON
TEMPERATURES. SHORT TERM MODELS SUCH AS THE RAP AND TEXAS TECH WRF
SUGGEST PARTS /IF NOT ALL/ OF THE REGION WILL REMAIN SOCKED IN LOW
CLOUDS FOR MUCH OF THE DAY...BUT THE MAIN DIAGNOSTIC MODELS WANT
TO SCATTER MUCH OF THE REGION OUT THIS AFTERNOON...EXCEPT FOR
MAYBE THE NORTHEASTERN COUNTIES. WITH THE UPPER LEVEL TROUGH
SWINGING ACROSS OKLAHOMA TODAY AND NORTH TO NORTHWEST FLOW THROUGH
THE MID LEVELS OF THE ATMOSPHERE...THIS IS OFTEN A SITUATION WHERE
CLOUDS DO REMAIN AROUND FOR MUCH OF THE DAY AND TEMPERATURES STAY
MUCH COOLER. HIGH CLOUDS STREAMING OVER THE AREA SHOULD ALSO WORK
AGAINST EROSION OF THE LOWER LEVEL CLOUDS...BUT THE HIGH CLOUDS
MAY SHIFT EAST THIS AFTERNOON AS THE UPPER LEVEL TROUGH CONTINUES
MOVING EAST. EVEN THOUGH CONFIDENCE IN THIS SCENARIO IS NOT VERY
HIGH DUE TO UNCERTAINTY ON IF AND WHERE THE CLOUDS WILL
BREAK...HAVE DECIDED TO ADJUST THE SKIES TO MOSTLY CLOUDY AND
CLOUDY FOR THE REMAINDER OF THE DAY. ALSO...ADJUSTED HIGH
TEMPERATURES NORTH OF I-20 DOWN A FEW DEGREES BUT DID NOT
ADJUST TEMPERATURES ELSEWHERE. OVERALL..THE FORECAST CALLS FOR A
WARM-UP OF ABOUT 5 DEGREES FROM CURRENT TEMPERATURES...EXCEPT IN
THE WEST WHERE THINNING CLOUDS THIS AFTERNOON MAY ALLOW TEMPS TO
WARM ANOTHER 5-10 DEGREES.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 329 AM CST TUE JAN 1 2013/
POSITIVE-TILTED LONGWAVE TROUGH CONTINUES FROM ROCKIES INTO THE
MISSISSIPPI VALLEY ALOFT. ONE SHORTWAVE WAS ROTATING NORTHEAST OUT
OF NEW MEXICO WITH ANOTHER DROPPING SOUTH THROUGH WYOMING AND INTO
COLORADO AND KANSAS. AT THE SURFACE...A WEAK FRONTAL WAVE WAS DRAPED
NEAR THE I-10 CORRIDOR WITH A WEAK SURFACE LOW ACROSS SOUTH TEXAS.
DRIER AIR WAS SLOWLY FILTERING ACROSS THE RED RIVER VALLEY INTO
AREAS NORTH OF I-20.
SHORT TERM FORECAST IS A BIT TRICKY THIS MORNING WITH COLD AIRMASS
ONLY 1000-2000 FT DEEP ACROSS NORTH TEXAS...MORE SHALLOW THE
FURTHER SOUTH OF I-20 YOU GO. PATCHY DENSE FOG AND DRIZZLE WAS
OCCURRING WITHIN THE MORE SHALLOW COOL AIRMASS SOUTH OF THE
I-20/30 CORRIDORS. ALSO...WEAK ISENTROPIC ASCENT WAS RESULTING IN
SCATTERED AREAS OF VERY LIGHT RAIN ACROSS OUR CENTRAL TEXAS COUNTIES.
WE EXPECT THE PATCHY DENSE FOG/RAIN/ DRIZZLE TO CONTINUE MAINLY
SOUTH OF A GREENVILLE/SULPHUR SPRINGS-GRANBURY-COMANCHE LINE THROUGH
MID-LATE MORNING. THIS WILL NOT INCLUDE THE DFW METRO AND POINTS
NORTH...PER AFOREMENTIONED DRIER AIR FILTERING SOUTH OUT OF OKLAHOMA
WITH DEEPER MIXING TO OCCUR. MID-HIGH LEVEL RETURNS HAVE BEEN
INCREASING ON REGIONAL RADAR AND WITHIN THE STRONG SOUTHWEST FLOW
ALOFT ACROSS THE NORTHWEST COUNTIES... BUT ANY LIGHT PRECIPITATION
THAT WOULD FALL FROM THESE HIGH DECKS WILL LIKELY EVAPORATE WELL
BEFORE REACHING THE SHALLOW AND SATURATED FRONTAL INVERSION BELOW
WITH VERY DRY AIR NOTED ON 00Z FWD SOUNDING JUST ABOVE THE FRONTAL
INVERSION. WILL NOT INSERT POPS AT THIS TIME...BUT WILL MONITOR
OBSERVATIONS CAREFULLY AS TEMPERATURES FALL INTO THE MID- UPPER
30S ACROSS THESE AREAS BY SUNRISE.
EXPECT RAIN CHANCES TO END ACROSS THE CENTRAL TEXAS AND FAR SOUTHEAST
COUNTIES BY AFTERNOON...AS THE SHORTWAVE OVER NEW MEXICO TRACKS
EAST ACROSS OKLAHOMA AND THE SURFACE WAVE TO OUR SOUTH HEADS INTO
THE NORTHERN GULF OF MEXICO. WITH THE ENSUING SUBSIDENCE...EXPECT
AT LEAST PARTIAL SUNSHINE ACROSS THE WESTERN HALF OF THE AREA THIS
AFTERNOON AND EVENING...WITH CLEARING OVERNIGHT. A SPLIT FLOW
PATTERN DEVELOPS RIGHT ACROSS THE RED RIVER VALLEY AND NORTH TEXAS
BY WEDNESDAY WITH SUBSEQUENT AND SHALLOW SURGES OF POLAR AIR BEING
REINFORCED ACROSS THE CWA. HIGHS WILL BE IN THE 40S WITH 50S IN
THE SOUTH THROUGH THE WEEK WITH THE AREA REMAINING DRY AND LITTLE
PRECIPITATION EXPECTED. TWO PIECES OF SHORTWAVE ENERGY WITHIN BOTH
THE SUBTROPICAL AND POLAR STREAMS MERGE ACROSS NEW MEXICO AND WEST
TEXAS ON LATER THURSDAY INTO FRIDAY NIGHT...BUT IT APPEARS BEST
MOISTURE WILL BE CONFINED WELL SOUTH OF OUR AREA AS THIS
DISTURBANCE LIFTS ACROSS THE AREA. NO RAIN IS EXPECTED WITH ONLY
INCREASING CLOUDINESS DURING THIS PERIOD.
MEDIUM RANGE MODELS KEEP IT DRY AND SEASONABLE BY THE WEEKEND...THEN
LOSE TOUCH WITH EACH OTHER ON SOLUTION HEADING INTO EARLY NEXT
WEEK. WE HAVE MAINTAINED A DRY FORECAST FOR THE NEXT WEEK AND
BEYOND.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 45 28 45 29 48 / 10 5 5 5 5
WACO, TX 51 30 46 30 49 / 40 5 5 5 10
PARIS, TX 43 27 43 27 46 / 20 5 5 5 5
DENTON, TX 44 25 45 26 47 / 10 5 5 5 5
MCKINNEY, TX 43 24 44 27 46 / 10 5 5 5 5
DALLAS, TX 46 29 46 29 49 / 10 5 5 5 5
TERRELL, TX 47 29 44 28 49 / 20 5 5 5 5
CORSICANA, TX 49 30 46 30 50 / 40 5 5 5 10
TEMPLE, TX 53 31 47 31 50 / 50 5 5 5 10
MINERAL WELLS, TX 42 23 45 26 47 / 10 5 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/82
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1012 AM CST TUE JAN 1 2013
.DISCUSSION...
HEAVIER PRECIP HAS SHIFTED OFFSHORE AND IS ALONG THE COLD FRONT
OVER THE COASTAL WATERS OUT BEYOND 20NM. THE FRONT SHOULD CONTINUE
TO MOVE SOUTHEAST THOUGH SLOWLY. PATCHY LIGHT RAIN WILL CONTINUE
THIS MORNING MAINLY OVER THE SOUTHERN HALF OF THE AREA INTO THE
EARLY AFTERNOON. AS LIFT WITH APPROACHING SHORTWAVE OVER THE HILL
COUNTRY NEARS EXPECT THE PRECIP TO SHIFT EAST AND LIGHTEN.
OVERCAST SKIES WILL PREVAIL THROUGH THE AFTERNOON HOURS BUT MAY
BECOME BROKEN THIS EVENING IN THE NORTHWESTERN AREAS WITH MAINLY
HIGH CLOUDS. THE LIGHT PRECIP AND COLD AIR ADVECTION SHOULD KEEP
TEMPERATURES IN THE MID 40S TO MID 50S WITH NEAR STEADY
TEMPERATURES. WILL LIKELY DO AN UPDATE AROUND 1130 OR NOON TO
CLEAR OUT PRECIP IN THE WEST AND NORTHWEST.
AS OF 1005 AM THIS MORNING GALVESTON HAS HAD A RECORD SETTING 3.99"
OF RAIN AND IS STILL FALLING THOUGH LIGHTER NOW.
45
&&
.PREV DISCUSSION... /ISSUED 529 AM CST TUE JAN 1 2013/
UPDATE...
SEE 12Z AVIATION DISCUSSION.
AVIATION...
MODELS DID NOT INITIALIZE PARTICULARLY WELL THIS MORNING SO
CONFIDENCE IS RATHER LOW. WENT WITH A GFS/RAP BLEND. AREA OF HEAVY
RAIN/TSRA ALONG THE COAST WILL MOVE OFFSHORE IN THE NEXT HOUR OR
SO. THIS WILL LEAVE JUST SOME PATCHY LIGHT RAIN FOR THE NEXT
COUPLE OF HOURS OVER THE REST OF SE TX. THE RAP MASS FIELDS KEEPS
MOST OF THE RAIN AWAY FROM AREA TAF SITES. A PRE-FRONTAL TROUGH IS
APPROACHING THE COAST WITH THE ACTUAL FRONT STILL LAGGING A FEW
HOURS BEHIND. AM EXPECTING WINDS TO SHIFT TO THE NORTH AND
INCREASE THIS MORNING. CIGS ARE THE OTHER ISSUE AND FCST SOUNDINGS
ARE PESSIMISTIC WITH CIGS TODAY. WILL MAINTAIN LIFR CIGS THROUGH
18Z AND THEN SHOW IMPROVEMENT TO VFR CONDS BY MID AFTN. 43
PREV DISCUSSION... /ISSUED 451 AM CST TUE JAN 1 2013/
DISCUSSION...
IT IS GOOD TO SEE RAIN ON THE RADAR ACROSS SE TX AS WE HEAD INTO
THE NEW YEAR. IT LOOKS LIKE COLLEGE STATION MAY BE THE ONLY
CLIMATE SITE WITH ABOVE NORMAL PRECIPITATION FOR THE YEAR WITH
HOUSTON IAH...HOUSTON HOU AND GALVESTON ALL SHOWING RAINFALL
DEFICITS TO END THE YEAR. THE OTHER CLIMATE NOTE IS THAT 2012
SHOULD GO DOWN AS THE WARMEST YEAR ON RECORD FOR HOUSTON. SEE MORE
DETAILS IN THE CLIMATE SECTION.
CURRENTLY HAVE A LINE OF SHOWERS AND THUNDERSTORMS FROM SW LA
INTO SE TX AND ALONG THE UPPER TX COAST. MOST OF THE HEAVY
RAINFALL SHOULD BE CONCENTRATED RIGHT ALONG THE IMMEDIATE COAST
INCLUDING GALVESTON IS AND BOLIVAR. THIS ACTIVITY SHOULD SLOWLY
MOVE EAST. A COLD FRONT IS SLOWLY PUSHING INTO THE AREA WITH A
PRE-FRONTAL TROUGH STALLED ACROSS THE HOUSTON AREA. BROAD UPPER
LEVEL TROUGH REMAINS OVER THE DESERT SW WITH SW JET FLOW FROM BIG
BEND OF TX TO THE OHIO RIVER VALLEY. RIGHT REAR QUAD OF UPPER JET
OR RIGHT ENTRANCE REGION SHOULD MOVE OVER TX TODAY AND WED BASED
ON SHORT RANGE MODELS. OVERALL THE SET UP IS FAVORABLE FOR RAIN OR
ELEVATED SHOWERS. DRIER AIR SHOULD MOVE INTO THE AREA LATER TODAY
AND TONIGHT WHICH SHOULD KEEP PRECIP CHANCES CONFINED TO THE
SOUTHERN HALF OF THE FORECAST AREA AND THE COASTAL WATERS. BASED
ON 00Z MODEL SUITE THINK MAJORITY OF RAINFALL WILL REMAIN OFF THE
COAST SO TAILORED POPS CLOSER TO THAT THINKING. THIS MEANS KEEPING
20/30 POPS IN THE FORECAST ALONG THE COAST THROUGH MID WEEK.
WITH JET FLOW REMAINING SW THROUGH THE END OF THE WEEK...LIKELY
HAVE MOSTLY CLOUDY CONDITIONS WHICH WITH COOLER AIRMASS WILL KEEP
TEMPS A GOOD 5 DEGREES BELOW NORMAL. DECIDED TO SHIFT SOME 20 POPS
INTO FRI NIGHT AND SAT MORNING. GFS SHOWS ANOTHER SHORTWAVE TROUGH
PUSHING PAST THE AREA DURING THIS TIME WITH THE ECMWF SLOWER.
SPLIT THE DIFFERENCES A BIT WITH THE TIMING OF THE DISTURBANCEBUT
WHILE THERE MAY BE LARGE SCALE ASCENT FOR PRECIP...NOT SURE HOW
MUCH MOISTURE WILL BE AVAILABLE. HIGH PRESSURE SHOULD BUILD INTO
THE AREA AGAIN OVER THE WEEKEND. OVERALL EXPECT TEMPS TO CREEP UP
TO NORMAL LEVELS FOR THE WEEKEND AND EARLY NEXT WEEK. SOUTHERLY
RETURN FLOW AND INCREASED GULF MOISTURE IS NOT EXPECTED TO OCCUR
UNTIL NEXT TUE.
39
MARINE...
A PRE-FRONTAL TROUGH AND ASSOCIATED WIND SHIFT WAS APPROACHING THE
COAST. A COLD FRONT LAGGED BEHIND...AND AT 2 AM THE FRONT EXTENDED
FROM LUFKIN TO COLLEGE STATION. THE FRONT WILL CONTINUE TO SAG SOUTH
AND THIS FEATURE SHOULD CROSS THE COAST BETWEEN 11-13Z. WINDS WILL
QUICKLY SHIFT TO THE NORTH AND INCREASE TO GREATER THAN 20 KNOTS
OVER THE GULF. AN SCA WILL REMAIN IN EFFECT FOR THE GULF WATERS
THROUGH 21Z AND WILL LIKELY BE EXTENDED LONGER WITH THE AFTN UPDATE.
AN SCEC WILL BE REQUIRED FOR THE BAYS TODAY. STRONG WINDS ARE
EXPECTED FOR MOST OF THE WEEK AND SCA/SCEC FLAGS WILL BE NEEDED FOR
MUCH OF THE WEEK AHEAD. TIDES ARE ABOVE NORMAL BUT OFFSHORE WINDS
WILL LOWER TIDE LEVELS BY AFTERNOON AND TIDE LEVELS WILL REMAIN
BELOW NORMAL ON THURSDAY. 43
CLIMATE...
NO BIG SURPRISE WITH REGARD TO TEMPERATURES. DECEMBER 2012 WAS
VERY WARM...AVERAGING 3 TO 5 DEGREES WARMER THAN THE 30 YEAR
NORMALS. 2012 WILL ALSO HAVE THE DISTINCTION OF BEING THE WARMEST
YEAR ON RECORD FOR THE CITY OF HOUSTON. THE UNOFFICIAL 2012
AVERAGE TEMPERATURE FOR THE CITY OF HOUSTON WAS 72.1 DEGREES. THE
PREVIOUS WARMEST YEAR ON RECORD WAS 71.9 DEGREES IN 1962.
FWIW...THE AVERAGE TEMPERATURE IN 2011 WAS 71.8 DEGREES WHICH WAS
THE THIRD WARMEST YEAR ON RECORD.
COLLEGE STATION HAD AN AVERAGE TEMPERATURE IN 2012 OF 71.6 DEGREES
WHICH TIES LAST YEAR FOR THE WARMEST YEAR ON RECORD.
THE CITY OF GALVESTON ALSO RECORDED IT`S WARMEST YEAR ON RECORD WITH
AN AVERAGE TEMP OF 73.9 DEGREES. THE PREVIOUS WARMEST YEAR WAS 72.6
DEGREES BACK IN 2006. THE SIX WARMEST YEARS ON RECORD FOR
GALVESTON HAVE OCCURRED SINCE 1994.
HOBBY AIRPORT ALSO RECORDED IT`S WARMEST YEAR ON RECORD. THE AVERAGE
ANNUAL TEMP WAS 72.6 DEGREES BESTING LAST YEARS RECORD VALUE OF
72.4 DEGREES. THE EIGHT WARMEST YEARS ON RECORD HAVE OCCURRED
SINCE 1998.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 55 36 49 34 52 / 50 10 10 10 10
HOUSTON (IAH) 59 41 50 37 54 / 80 20 10 10 10
GALVESTON (GLS) 64 46 51 43 53 / 90 30 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH THIS EVENING FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...45