Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/17/12
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
617 PM MST MON JAN 16 2012
.UPDATE...
UPDATED FORECAST PACKAGE TO TAKE DOWN WINTER WEATHER HIGHLIGHTS
FOR THE SOUTHWEST MOUNTAINS. BACK EDGE OF SNOW ALONG LEADING EDGE
OF TROF AXIS WILL CONTINUE MOVING THROUGH THE CENTRAL MTS AND
ACROSS EAST CENTRAL CO OVER THE NEXT SEVERAL HOURS. HAVE INCREASED
POPS FOR NRN EL PASO COUNTY WHERE RUC13 AND LATEST RADAR TRENDS
SUGGEST AT LEAST A PERIOD OF SCATTERED SNOW SHOWERS ALONG THE NRN
EL PASO CO BORDER THROUGH 04Z. NOT EXPECTING MUCH ACCUMULATION AS
THESE SHOULD BE FAIRLY BRIEF IN NATURE. -KT
&&
.PREV DISCUSSION... /ISSUED 226 PM MST MON JAN 16 2012/
SHORT TERM...
(TONIGHT AND TUESDAY)
CURRENTLY...
PACIFIC FRONT HAS MOVED EAST OF THE I-25 CORRIDOR AND WAS LOCATED BY
RADAR AT 1 PM ALONG THE PUEBLO/OTERO AND CROWLEY COUNTY LINE. SAT
PIX AND SIMULATIONS SHOW BROAD TROUGH AT MID LEVELS WAS LOCATED OVER
THE E UTAH AND WAS PROGRESSING EAST. CLOUDINESS ASSOCIATED WITH THE
TROUGH OVER THE MTNS WAS BECOMING MORE CONVECTIVE IN NATURE AND
CLOUD TOPS WERE WARMING...ESPECIALLY OVER THE S CO.
REST OF TODAY AND THIS EVENING...
AS PAC FRONT MOVES EAST ACROSS THE E PLAINS...TEMPS WILL LIKELY RISE
FROM THEIR CURRENT VALUES. THIS PAC FRONT WILL LIKELY ADVANCE AS FAR
EAST AS W KIOWA/KLAA/KSPD LINE BEFORE CRASHING INTO THE MODIFIED
ARCTIC BOUNDARY THAT WILL DROP SOUTH/BACK DOOR INTO THE AREA ACROSS
THE REGION THIS EVENING. WITH THE STRONG WESTERLY WINDS BLOWING OVER
MOST OF THE PLAINS THIS EVENING TEMPS WILL ONLY GRADUALLY DROP...AND
WILL REMAIN ON THE MILD SIDE UNTIL THE ARCTIC FRONT MOVES THROUGH.
AS BROAD TROUGH GETS CLOSER WINDS AT MTN TOP LEVELS WILL SHIFT TO A
MORE WESTERLY AND THEN NORTHWESTERLY COMPONENT. SNOWS ACROSS THE SAN
JUANS WILL GRADUALLY DECREASE AS THIS HAPPENS AND PLAN TO LET THE
ADVISORY END AT ITS SCHEDULED TIME (6 PM). SNOW WILL CONTINUE ACROSS
THE CENTRAL MTNS INTO THE MID EVENING HOURS.
LATER TONIGHT...
MODIFIED ARCTIC BOUNDARY SHOULD ENTER KIOWA COUNTY AND NORTHERN EL
PASO COUNTY AROUND 03-04Z. WE WILL LIKELY SEE SOME INCREASE IN
CLOUDS AND CANNOT RULE OUT A BRIEF SNOW SHOWER NORTH OF US50 AS THE
BOUNDARY MOVES THROUGH. THE BOUNDARY WILL THEN CONTINUE TO DROP
SOUTH AND WILL BE THROUGH THE ENTIRE CWA BY 09Z.
WINDS OVER THE HIGHER TRRN WILL ABATE CONSIDERABLY.
TOMORROW...
IT WILL BE MOSTLY SUNNY MOST AREAS BUT IT WILL BE MUCH COLDER THAN
TODAY. HIGH TEMPS WILL LIKELY ONLY IN THE LOWER TO MID 30S ACROSS
MOST OF THE REGION. AREAS WHICH MAY BE A BIT WARMER WILL BE DOWN
NEAR KTAD WHERE DOWNSLOPE OFF THE RATON MESA MAY ALLOW TEMPS TO
APPROACH NEAR 40. OVER THE MTNS ALONG THE CONTDVD EXPECT PARTLY
CLOUDY SKIES WITH ISOLD SNOW SHOWERS...ESPECIALLY OVER THE C MTNS.
WINDS OVER THE MTNS WILL BE PICKING UP ONE AGAIN AS ANOTHER SPEED
MAX APPROACHES THE REGION. BY LATE IN THE DAY WINDS WILL BE IN THE
20 TO 40 MPH RANGE...ESPECIALLY C MTNS AND PIKES PEAK.
LONG TERM...
(TUESDAY NIGHT THROUGH MONDAY)
..CONTINUING MOUNTAIN SNOW AND BREEZY CONDITIONS...
ZONAL FLOW IS FORECAST TO PERSIST THROUGH MUCH OF THE EXTENDED
WITH SEVERAL EMBEDDED WAVES AND PERIODS OF STRONG GUSTY WINDS. THE
PATTERN WILL BE DOMINATED BY A LARGE LOW PRESSURE CENTER OVER
CENTRAL CANADA WHICH WILL PRODUCE THE ZONAL FLOW.
THE FIRST MAIN CONCERN WILL BE THE POTENTIAL FOR STRONG WINDS
TUESDAY NIGHT INTO WEDNESDAY MORNING. A SHORTWAVE TROUGH IS
FORECAST TO TRACK ACROSS WYOMING INTO THE CENTRAL PLAINS WITH A
STRONG JET STREAM MOVING OVER THE ROCKIES. MODELS INDICATING A
PERIOD...ROUGHLY FROM 03Z THROUGH AROUND 18Z WEDNESDAY FOR STRONG
WINDS. DOWNSLOPE POTENTIAL DOES NOT LOOK OVERLY GREAT WITH BRUTE
FORCE BEING THE MOST LIKELY SCENARIO. THINK THE ELEVATIONS ABOVE
11 KFT WILL LIKELY SEE GUSTS IN EXCESS OF 80 MPH WHILE THE LOWER
ELEVATIONS SEE GUSTS UP TO 50 MPH. THE STRONGEST WINDS WILL LIKELY
OCCUR ALONG THE EASTERN MOUNTAINS AND ADJACENT PLAINS WEST OF
I-25. WINDS WILL SUBSIDE DURING THE LATE AFTERNOON AS THE UPPER
LEVEL JET AND TROUGH SHIFT EAST OF THE REGION. MODELS ALL
DEVELOPING LIGHT SNOWFALL TUESDAY NIGHT AND WEDNESDAY ACROSS THE
CENTRAL MOUNTAINS BUT ACCUMULATIONS WILL ONLY BE AN INCH OR TWO.
THE NEXT FAST MOVING SHORTWAVE TROUGH IS FORECAST TO MOVE ACROSS
THE ROCKIES WEDNESDAY EVENING INTO THURSDAY. EXPECT LIGHT SNOW TO
SPREAD SOUTH ALONG THE CONTINENTAL DIVIDE INTO THE SAN JUANS
DURING THIS TIME PERIOD. AGAIN SNOW ACCUMULATIONS WILL BE MINOR
WITH ONLY AN INCH OR TWO.
A STRONGER STORM SYSTEM IS FORECAST TO MOVE INTO THE REGION FRIDAY
THROUGH SUNDAY WITH A CHANCE AT HEAVIER SNOW FOR THE CONTINENTAL
DIVIDE. EXPECT LIGHT SNOW TO PICK UP IN INTENSITY FRIDAY NIGHT AS
THE MAIN JET CORE BEGINS TO MOVE OVER THE ROCKIES. THERE APPEARS
TO BE ANOTHER SHOT AT DOWNSLOPE WINDS FRIDAY NIGHT INTO SATURDAY
MORNING BASED ON THE GFS SOUNDING AND MID LEVEL DATA. CURRENT
SOUNDINGS INDICATE A NICE MOUNTAIN TOP INVERSION WITH SOME WEAK
REVERSE SHEAR WHICH ARE ALL CONDUCIVE TO DOWNSLOPE WINDS. FOR NOW
HAVE STARTED TO INCREASE MOUNTAIN AND LEE SLOPE WINDS WHICH WILL
HAVE TO BE MONITORED.
MODELS IN SLIGHTLY BETTER AGREEMENT THIS AFTERNOON IN REGARDS TO
THE POTENTIAL FOR A STRONG SNOW STORM BEGINNING ON MONDAY. THERE
ARE MODEL DIFFERENCES IN STORM TRACK AND WIND FIELDS...BUT SOME OF
THE MODEL SOLUTIONS SUGGEST AN ACCUMULATING SNOW STORM FOR ALL OF
SOUTHERN COLORADO. THIS IS STILL A LONG WAYS OUT BUT WILL HAVE TO
BE WATCHED.
TEMPERATURES...WITH WESTERLY DOWNSLOPING WINDS...AFTERNOON HIGHS
WILL CLIMB INTO THE MID TO UPPER 50S FOR THE PLAINS. THE EXCEPTION
WILL BE THE LOWER ARKANSAS RIVER VALLEY WHERE HIGHS WILL REMAIN IN
THE 40S WITH WARMER TEMPERATURES BY THE END OF THE WEEK. 88
AVIATION...
VFR EXPECTED NEXT 24H AT ALL 3 TAF SITES...KCOS...KPUB AND KALS.
GUSTY WINDS WILL CONTINUE AT KPUB AND KCOS THIS EVENING BEFORE
DECREASING LATER THIS EVENING. PAC FRONT HAS ALREADY CROSSED THE
PLAINS TAF SITES AND THE ARCTIC FRONT WILL GRADUALLY MOVE THROUGH
THIS EVENING.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR COZ060.
&&
$$
31/44
AREA FORECAST DISCUSSION
NWS DENVER CO
453 PM MST MON JAN 16 2012
.UPDATE...LATEST RADAR SHOWS A GOOD BAND OF SNOW ASSOCIATED WITH
UPPER TROUGH AND MID LEVEL COLD FRONT SPREADING OFF THE FOOTHILLS.
WE HAVE INCREASED SNOW CHANCES FOR DENVER METRO AREA AND NORTHEAST
ACROSS THE PLAINS DUE TO THIS FEATURE...AND SHALLOW UPSLOPE
SLOWING DISSIPATION OF THE BAND IN MEAN WESTERLY FLOW ALOFT.
&&
.AVIATION...CURRENT FORECAST IS ON TRACK WITH SHOWERS SPREADING
SOUTHEAST ACROSS THE FRONT RANGE AIRPORTS FROM NOW TIL 04Z.
VISIBILITIES COULD DROP TO 1/2 MILE AND BRIEFLY 1/4 MILE IN THE
HEAVIEST SHOWERS PER UPSTREAM OBS FROM KCYS AND FORT COLLINS
SPOTTER REPORTS...SO HAVE LOWERED THE TEMPO VSBYS IN TAFS.
&&
.PREV DISCUSSION... /ISSUED 335 PM MST MON JAN 16 2012/
SHORT TERM...WIDE BAROCLINIC ZONE ASSOCIATED WITH THE UPPER TROUGH
AND SFC COLD FRONT PASSING OVER THE MOUNTAINS AT THIS HOUR. FRONTAL
BNDRY HAS MOVED THROUGH JACKSON COUNTY AS NOTED BY A SUDDEN DROP IN
TEMPERATURE AND ABRUPT SHIFT TO NORTHWEST WINDS AT WALDEN WHERE THE
TEMPERATURE FELL 11 DEGS F IN LESS THAN AN HOUR. BANDED SLANTWISE
CONVECTION...I.E. SNOWFALL...STREAKING CROSSING THE HIGH COUNTRY
JUST AHEAD OF THE 700-500MB TROUGH AXIS. HAVE NOTICED A STEADY
INCREASE IN SNOW INTENSITY AND COVERAGE IN THE PAST COUPLE OF HOURS
WITH RUC QG VERTICAL FIELDS INDICATING WEAK TO MODERATE LARGE SCALE
ASCENT CENTERED OVER THE NRN MTNS. WHERE THIS PRECIP GOES FROM HERE
AND HOW EXTENSIVE IT WILL BE DEPENDS ON WHICH MODEL YOU LOOK AT.
BOTTOM LINE...THE NAM IS DRIER AND A BIT SLOWER WITH ITS EASTWARD
PROGRESS THAN THE GFS...ECMWF AND SREF. WHEREAS...THE GFS AND SREF
SHOW A WIDER AREA OF PRECIPITATION/SNOW FIELD ACROSS NERN COLORADO
THIS EVENING...WITH A COUPLE INCHES OF SNOW ACCUM BY MIDNIGHT
ACROSS THE NORTHEAST CORNER OF THE STATE. OVERALL SEE BANDED PRECIP
TRANSLATING SOUTHWARD ACROSS THE NERN PLAINS THIS EVENING...WITH THE
BACK EDGE OF THIS PRECIP SOUTHEAST OF THE DENVER METRO AREA BY
AROUND 05Z..AND OUT OF THE CWFA (LINCOLN COUNTY) POSSIBLY BY 08Z OR
09Z TONIGHT. EXPECTED SNOW ACCUMULATION WITHIN THE I-25 URBAN
CORRIDOR MINIMAL AT BEST...PERHAPS A HALF INCH ON GRASSY SURFACES
FROM ONE OF THE HEAVIER SNOW BANDS COMING OFF THE FOOTHILLS EARLY
THIS EVENING. AGAIN...APPEARS THE NORTHEAST CORNER IN THE BEST
POSITION TO SEE ACCUMULATING SNOWFALL THIS EVENING.
LATER TONIGHT...SHOULD SEE GUSTY NORTHWEST WINDS USHERING IN DRIER
AND COLDER AIR FROM WYOMING. CLEARING LATE WILL ALLOW FOR STRONG
RADIATIONAL COOLING CAUSING TEMPERATURES TO PLUNGE WELL BELOW ZERO
IN THE HIGH MOUNTAIN VALLEYS. MIN TEMPERATURES ALSO QUITE COLD ON
THE PLAINS WITH SINGLE DIGITS ABOVE ZERO THE NORM BY MORNING LIGHT.
COULD SEE A FEW SUBZERO READINGS IN LOW LYING AREAS SUCH AS ALONG
THE SOUTH PLATTE RIVER.
ON TUESDAY...SWIFT NORTHWEST FLOW ALOFT CONTINUES OVER THE STATE
WITH A DRIER AIRMASS UPSTREAM. ANY SNOWFALL TOMORROW WILL BE
CONFINED TO THE HIGHEST PEAKS AND WEST FACING SLOPES ALONG THE
DIVIDE. EVEN THERE SNOW INTENSITIES WILL BE WEAK. TEMPERATURES WILL
STRUGGLE TO WARM TOMORROW WITH ONGOING COLD AIR ADVECTION. SEE
LITTLE CLOUD COVER ESPECIALLY EAST OF THE MTNS WITHE FLOW
REGIME.
LONG TERM...MAIN CONCERN FOR THE UPCOMING WEEK WILL BE THE HIGH
WIND POTENTIAL IN THE MOUNTAINS...FOOTHILLS AND ADJACENT PLAINS AND
DEVELOPING SNOW IN THE MOUNTAINS BY MIDWEEK. MOST OF THE WESTERN
U.S. WILL TRANSITION TO A STRONG AND ZONAL WEST TO NORTHWEST FLOW
ALOFT THIS WEEK. IT APPEARS THE STRONGEST WINDS WILL EFFECT THE
REGION LATE TUE NIGHT THROUGH EARLY THURSDAY AM AS A STRONG
130-150KT JET CORE LIFTS OUT ACROSS WYOMING ON WEDNESDAY. THE
SURFACE PRESSURE GRADIENT WILL TIGHTEN TO 10-15 MB ACROSS THE STATE
ON WED WHILE MOUNTAIN TOP STABILITY INCREASES. CROSS SECTIONS SHOW
AMPLIFIED MOUNTAIN WAVE DEVELOPING WITH 60-80KT OF CROSS BARRIER
FLOW. STILL A LOT OF QUESTION MARKS AS THERE ARE SOME CONFLICTING
PARAMETERS. THERE IS A LOT OF VERTICAL SHEAR ESPECIALLY EARLY ON
WEDNESDAY FOR AN AMPLIFIED MOUNTAIN WAVE. SHEAR PROFILE IMPROVES A
BIT BY WED NIGHT AS THE MAIN JET IS WELL EAST OF COLORADO.
HOWEVER...THE MOUNTAIN TOP LEVEL STABILITY LOOKS QUITE IMPRESSIVE AS
STRONG MID LEVEL WARMING DEVELOPS A STRONG INVERSION IN THE
700-750MB LAYER. ALONG WITH THE TIGHTENING SURFACE GRADIENT THIS
SHOULD HELP SHIFT THE STRONGER WINDS DOWN OVER THE LOWER FOOTHILLS
AND AT THE BASE OF THE FOOTHILLS. ON THE OTHER HAND...INCREASING
MOISTURE IN THE MOUNTAINS ON WEDNESDAY MAY HELP NEGATE THE STRONGEST
WINDS AND DIMINISH THE MOUNTAIN WAVE EFFECTS. STILL ENOUGH FACTORS
TO WARRANT A HIGH WIND WATCH GIVEN THE VERY STRONG MOUNTAIN TOP FLOW
AROUND 80KTS. WILL PLAY THE WATCH TIMING IN A RATHER BROAD SCOPE FOR
NOW BUT HOPEFULLY ABLE TO NAIL DOWN TIMING AND STRENGTH BETTER IN
THE NEXT FEW DAYS.
THE NEXT QUESTION WILL BE WHAT TO DO WITH ZONES 33 AND 34 IN TERMS
OF WIND VERSUS SNOW POTENTIAL...BUT THINK THE WIND WILL BE THE
BIGGEST FACTOR HERE. MOISTURE DEPTH DOES INCREASE WEDNESDAY
AFTERNOON AND NIGHT BUT GIVEN THE INCREASING STABILITY...LAPSE RATES
DECREASE TO 2.5-4C/KM BY WED NIGHT. LOCAL SNOW MODEL GENERATES UNDER
ADVISORY AMOUNTS FOR NOW. WILL AT LEAST BUMP UP POPS TO LIKELY FOR
ZONES 31 AND 33 GIVEN THE STRONG WESTERLY OROGRAPHIC FLOW.
ACROSS LOWER ELEVATIONS IT WILL BE A DRY AND A MILD WEEK AHEAD WITH
TEMPERATURES WELL ABOVE NORMAL BY MIDWEEK WITH READINGS IN THE 50S
AND LOWER 60S THROUGH THE WEEKEND.
AVIATION...COLD FRONT ALREADY SLIPPING INTO NORTHEAST COLORADO FROM
WYOMING AS OF 22Z. AS THIS FRONT MOVES SOUTH ALONG THE FOOTHILLS
SHOULD SEE BANDS OF LIGHT SNOWFALL FORMING ALONG AND BEHIND THIS
FRONTAL BOUNDARY. AT CURRENT SPEED COULD SEE THE FRONT AND ITS
ASSOCIATED SHIFT TO GUSTY NORTH-NORTHEAST WINDS IN THE NEXT 60 TO 90
MINUTES...WITH THE HEAVIER SHOWERS BEHIND THIS BOUNDARY. MVFR
CEILINGS NOW ARE EXPECTED TO LOWER TO LOWER TO BELOW 3000 FEET AGL
AFTER 00Z/TUE WIT LOCAL LIFR CEILINGS WIT PASSING SNOW SHOWERS.
HEAVIER SHOWERS COULD ALSO PRODUCE VSBYS BELOW 2 MILES. AT THIS
TIME...IT APPEARS THAT PASSING SNOW SHOWERS WILL PRODUCE MINIMAL
SNOW ACCUMULATION IN THE DENVER ARE...PROBABLY NO MORE THAN A HALF
INCH ON GRASSY SURFACES. SHOWERS ARE EXPECTED TO MOVE OUT OF THE
DENVER AREA BY AROUND 05Z THIS EVENING...AND BY 07Z...SHOULD SEE
SKIES CLEARING WITH A SURGE OF DRIER AND COLDER AIR MOVING DOWN FROM
WYOMING. ON TUESDAY...VFR CONDITIONS WITH LIGHT WEST TO SOUTHWEST
BREEZES FOR MOST OF THE DAY UNDER MOSTLY CLEAR SKIES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE TUESDAY NIGHT THROUGH THURSDAY MORNING
FOR COZ033>036-038-039.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....ENTREKIN
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
603 PM CST MON JAN 16 2012
.AVIATION...
CONDITIONS EXPECTED TO DETERIORATE LATER THIS EVE AND OVRNGT AS
COLD FRONT MOVES THROUGH WITH VFR CONDITIONS GIVING WAY TO
MVFR AND IFR CONDITIONS IN POSSIBLY A WINTRY MIX OF VERY LIGHT
RAIN OR DRIZZLE OR FREEZING DRIZZLE AND SNOW. PCPN EXPECTED TO GO
OVER TO ALL SNOW LATE TNGT AND PERSIST THROUGH TUE AM AS AN
UPPER LEVEL DISTURBANCE PASSES... WITH SOME ACCUMULATIONS
LIKELY AT KDBQ/KCID/KMLI. NW WINDS WILL BE INCREASING OVRNGT
WITH GUSTS OF 25-30 KTS DEVELOPING MID-LATE TUE AM THROUGH TUE
AFTN... WITH SOME REDUCED VSBYS IN BLOWING/DRIFTING SNOW POSSIBLE
MAINLY AT KDBQ. STRONG SUBSIDENCE IN WAKE OF DEPARTING DISTURBANCE
TUE AFTN TO LIKELY BRING RAPID CLEARING BY MID TO LATE TUE AFTN.
&&
.PREV DISCUSSION... /ISSUED 328 PM CST MON JAN 16 2012/
SYNOPSIS...
A COLD FRONT EXTENDED FROM NORTHERN LK MI SOUTHWEST THROUGH EASTERN
IOWA TO LOW PRESSURE OVER NORTHWEST MO LATE THIS AFTERNOON. SO FAR
NOT PRECIPITATION WAS OCCURRING IN THE VICINITY OF FRONT OR SURFACE
IN OR NEAR THE MID MISSISSIPPI VALLEY. THERE WAS STRONG THERMAL
GRADIENT RANGING FROM THE MID AND UPPER 60S OVER THE NORTHEAST
QUARTER OF MO TO THE MID 30S OVER NORTHEAST IOWA. LOW LEVEL
MOISTURE WAS STREAMING NORTH AHEAD OF THE LOW/FRONT WITH
WIDESPREAD MID AND UPPER 40 DEWPOINTS OVER MUCH OF NORTHEAST MO
INTO WEST CENTRAL IL. THE MIDWEST FRONT WAS SETUP AHEAD OF A 500MB
S/W TROF THAT WAS MOVING ACROSS THE CENTRAL/NORTHERN ROCKIES AT
18Z PER RUC PROGS AND WATER VAPOR IMAGERY.
SHORT TERM...TONIGHT AND TUESDAY...
A CHALLENGING FORECAST FOR THE OVER NIGHT HOURS WITH THE STRONG
COLD FRONT OVER THE AREA THIS EVENING DROPPING SOUTHEAST THROUGH
THE CWFA BY LATE EVENING. THEN SOME MID-LEVEL ENERGY MOVING
THROUGH LATE TONIGHT AFTER THE LOW LEVEL COLD AIR IS IN PLACE.
TUESDAY LOOKS LIKE A RAW WINDY DAY WITH STRONG CAA AND LINGER
FLURRIES OR LIGHT SNOW.
SO FAR WITH THIS SYSTEM PRECIPITATION HAS BEEN NON
EXISTENT...HOWEVER THAT APPEARS TO BE CHANGING AS WE GO INTO THE
OVERNIGHT HOURS. MODEL SOUNDINGS CONTINUE TO SHOW THE LOW LEVELS
SATURATING THIS EVENING WHICH SHOULD OCCUR AS THE COLD LOW LEVEL
AIR MOVES IN BEHIND THE FRONT THIS EVENING. SOME FORCING WILL BE
PRESENT IN THE LOW LEVELS IN THE FORM OF FGEN AT THE SAME TIME
MID/UPPER LEVEL RH WILL BE INCREASING AND COULD PROVIDE A FEEDER
MECHANISM FOR THE LOW CLOUDS...SO WENT WITH LOW POPS FOR LIGHT
PRECIPITATION THIS EVENING AS OPPOSED TO DRIZZLE. IF
PRECIPITATION OCCURS BEFORE MIDNIGHT THEN THE THERMAL PROFILES
WOULD FAVOR RAIN OVER THE SOUTHEAST HALF OF THE CWFA WITH A MIX OF
FZRA/SN OVER THE NORTHWEST HALF. BETTER FORCING WILL MOVE OVER THE
AREA AFTER MIDNIGHT WITH MID/UPPER FGEN INCREASING AHEAD OF VORT
MAX MOVING OUT OF THE WESTERN TROF. THE FGEN WILL BE CO-LOCATED
WITH A POCKET OF STEEPER MID LEVEL LAPSE RATES WHICH SUPPORTS A
NARROW BAND OF ENHANCED PRECIPITATION MAINLY FROM THE SOUTHWEST
CWA INTO NW IL. THERE MAY BE SOME FREEZING RAIN MIXED WITH THE
PRECIPITATION JUST AFTER MIDNIGHT BUT THE COLD AIR SHOULD DEEPEN
ENOUGH BY 09Z FOR ALL SNOW OVER THE CWFA. THE SNOW WILL LINGER
INTO THE MORNING AND END DURING THE AFTERNOON IN THE SOUTHWEST
WITH LINGERING FLURRIES IN THE NORTHEAST. BY TUESDAY AFTERNOON
SNOWFALL AMOUNTS ARE EXPECTED TO BE IN THE 1 TO 2 INCH RANGE OVER
THE NORTHWEST HALF WITH LESS THAN AN INCH IN THE SOUTHEAST HALF OF
THE CWFA. NORTHWEST WINDS GUSTING TO 25 TO 30 MPH TUESDAY MAY
CAUSE SOME BLOWING AND DRIFTING. OVERNIGHT TEMPERATURES SHOULD
FALL INTO THE TEENS NORTHWEST TO MID 20S SOUTHEAST. ONGOING STRONG
LOW LEVEL CAA AND CLOUDS WILL ALLOW TEMPERATURES TO CONTINUE
FALLING DURING THE DAY AND SHOULD BE IN THE TEENS BY MID AFTERNOON
OVER ALL BUT THE SOUTHWEST CORNER WHERE LOW TO MID 20S ARE
ANTICIPATED. ..DLF..
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...
TUESDAY NIGHT AND WEDNESDAY...LOOKING AT THE LATEST AVAILABLE
12Z RUN MODEL GUIDANCE...CLEARING AND COLD CONDITIONS STILL ON
TRACK FOR TUE NIGHT IN SUBSIDENCE WAKE OF THE EXITING GRT LKS SYSTEM
AND ARRIVAL OF LLVL RIDGE LOBE. SOME LOWS BELOW ZERO POSSIBLE IN
AREAS NORTH OF I80/FAVORED VALLEY REGIONS...OTHERWISE OTHER AREAS
TO BE IN THE SINGLE DIGITS ABOVE ZERO. THESE LATEST 12Z RUNS STILL
SUGGEST AN UPPER LEVEL WAVE WILL PROPAGATE OUT OF THE ACTIVE
PACIFIC NW REGION AND PASS ACRS PORTIONS OF MN AND WI CLIPPER-
STYLE IN FRESHLY ESTABLISHED BROAD NORTH-WESTERLIES...TO USHER YET
ANOTHER FRONT INTO THE CWA BY LATE WED NIGHT AND INTO THU MORNING.
STILL APPEARS A POSSIBILITY OF OR EVEN POST-FRONTAL LIGHT SNOW IN
MUCH OF THE CWA WED NIGHT AND INTO THU MORNING. FOR NOW...WILL ADD
A SLIGHT CHC FOR MEASURABLE SNOW IN THE FAR NORTHEASTERN CWA BUT
ADD FLURRIES FOR MUCH OF THE REMAINDER OF THE FCST AREA. THE 12Z
GFS REMAINS THE QUICKEST SOLUTION IN HANDLING THE FROPA MAKING IT
TO THE WESTERN OH RVR VALLEY BY 12Z THU AND POST-FRONTAL COLD RUSH
WELL IMPLANTED ACRS THE LOCAL AREA...BUT OTHER MODELS INCLUDING
THE ECMWF HAVE SPED UP THIS PROCESS AS WELL. THUS IT APPEARS A
COLD BLUSTERY LATE WED NIGHT-THU MORNING COULD BE IN STORE WITH
LOW SINGLE DIGIT LOWS BY DAWN THU AND WIND CHILLS IN THE DOUBLE
DIGITS BELOW ZERO.
THURSDAY THROUGH FRIDAY...ONGOING LIGHT SNOW AND FLURRIES TO
START THE PERIOD OFF THU MORNING...BUT AGAIN NORTHWEST WINDS IN
STOUT CAA/INCOMING SFC RIDGE PRESSURE GRADIENT COULD BE GUSTING OVER
30 MPH AND PRODUCING DOUBLE DIGIT BELOW ZERO WIND CHILL VALUES
THROUGH AT LEAST MID MORNING. PASSING 1025+ MB COLD HIGH PRESSURE
SYSTEM WITH ORIGINS FROM WESTERN CANADA WILL THEN SCOUR THINGS OUT
FOR THE REST OF THE DAY AND INTO THU EVENING BEFORE HIGH CLOUDS
INCREASE AGAIN FROM THE WEST AHEAD OF THE NEXT POTENTIAL SYSTEM. LLVL
BAROCLINICITY STILL TO GET ALIGNED PARALLEL UNDER THE DEVELOPING MEAN
FLOW NORTH-WESTERLIES ACRS OR NEAR THE DVN CWA ON THU AND TIGHTENING
UP AS THE PERIOD PROGRESSES. LATEST MEDIUM RANGE MODEL RUNS CONTINUE
TO PICK UP ON A MORE SUBSTANTIAL TYPE CLIPPER-LIKE WAVE PROPAGATING
DOWN IN THIS FLOW ALONG THE LLVL THERMAL RIBBON TOWARD WEEKS END.
THIS SYSTEM WILL LOOK TO UTILIZE SOME GULF MOISTURE FEED FROM
THE SOUTH...BUT THE MODELS CONTINUE TO VARY FROM RUN-TO-RUN ON HOW
FAR NORTH OR SOUTH THIS FEATURE WILL TRACK AS WELL AS INCOMING SPEED.
THEY STILL SUGGEST A WAVE STRONG ENOUGH TO PRODUCE 1-3 OR EVEN 2-4
INCHES OF SNOW SOMEWHERE IN THE REGION...WITH THE LATEST 12Z RUN
GFS NOW MAKING A DIRECT HIT ON THE CWA FROM LATE THU NIGHT INTO
FRI MORNING WITH WIDESPREAD 2-4 INCHES BY 18Z FRI BEFORE THE
SYSTEM SHUTTLES OFF TO THE EAST. THE NEW 12Z ECMWF IS NOW SLOWER
AND FURTHER NORTH...SUGGESTING A DRY THU NIGHT AND THEN ACCUMULATING
SNOWS OF 2-5+ INCHES MAINLY ACRS MN/NE IA AND SOUTH HALF OF WI ON
FRI. THE EURO DOES TRY TO DO SOME PHASING/DIGGING RIGHT OVER AND
JUST SOUTHEAST OF THE DVN CWA LATER FRI WHICH MAY THEN WRAP SOME
ACCUMULATING SNOWS BACK ON THE NORTHEASTERN AND NORTHERN CWA FRI
AFTERNOON AND INTO THE EVENING WITH ACCUMULATIONS POSSIBLE.
INTERESTING THAT THE LATEST RUNS ARE LESS BULLISH ON THE EXTENT OF
WARM DRAW FROM THE SOUTH SO FOR NOW WILL JUST ADVERTISE ALL SNOW
ON FRI INSTEAD OF A MIX IN THE SOUTH. BUT THERE IS TIME FOR LATER
RUNS TO AGAIN CHANGE ON THAT ASPECT. WILL KEEP MODERATE CHC POPS
GOING ALONG WITH THE SNOW WORDING ON FRI FOR NOW.
SATURDAY THROUGH MONDAY...LONG RANGE SIGNALS/ENSEMBLES AND TRENDS ON
PROJECTED H5 MB GEOPOTENTIAL HEIGHT FIELDS SUGGEST L/W TROF ENERGY TO
DIG ACRS THE WESTERN COAST...WITH RESULTANT FLATTENING FLOW TO MID
CONUS RIDGING TAKING PLACE BEHIND THE EXITING FRI SYSTEM OVER THE
WEEKEND. STRONG THERMAL MODERATION SIGNALS ARE THERE WITH A TAP INTO
ANOTHER ROUND OF BUILDING WARM POOL ACRS THE SOUTHERN PLAINS BY
SUNDAY...AS OPPOSED TO SAT WHICH NOW DOES NOT APPEAR WILL BE AS
MILD AFTER A COLD START/FRI NIGHT AND SOME DELAY IN RETURN FLOW.
THERMAL PROFILES ARE ALMOST THERE TO SUPPORT HIGHS NEAR 50 BY NEXT
SUNDAY WITH ENOUGH MIXING AND INSOLATION...BUT MUCH WILL DEPEND ON
ANY NEW SNOW COVER FROM THE FRI SYSTEM AND MOISTURE RETURN GOING INTO
CLOUD PRODUCTION LIMITING THE WARM UP POTENTIAL WHICH IS COMMON IN
THIS TYPE OF WAA SCENARIO. WILL TAKE THE PRECIP OUT FOR NEXT SUNDAY
UNDER THE EXPECTED THERMAL RIDGE...BUT NOT GO QUITE AS WARM AS THE
POTENTIAL IS FOR NOW....UPPER 30S IN THE FAR NORTH TO THE MID/UPPER
40S ALONG AND SOUTH OF I80. MODEL DISCREPANCIES AND PHASING ISSUES
APLENTY IN HANDLING EVENTUAL IN-LAND PROPAGATING WAVE ENERGY OUT OF
THE WESTERN TROFFINESS FOR LATE IN THE WEEKEND AND INTO EARLY NEXT
WEEK. BUT LOOKING AT LONG RANGE UPPER JET PLACEMENT AND AIRMASS
STEERING MECHANISMS THE ABOVE NORMAL THERMAL REGIME STILL LOOKS LIKE
IT WILL BE WELL IN PLACE BY THE TIME THESE WAVE SYSTEM AND ASSOCIATED
SFC FEATURES TRY TO PUSH ACRS THE MIDWEST. THUS MAINLY A RAIN THREAT
FOR THE MONDAY PERIOD...BUT CONFIDENCE ON THIS TIMING LOW. THE ECMWF
ACTUALLY PUSHES A FRONT THROUGH THE CWA SUNDAY NIGHT WITH A RAIN
THREAT...AND THEN IS DRY AND COOLER FOR MONDAY AS THE NEXT LARGE
SYSTEM ORGANIZES UPSTREAM AND LOOMS OVER THE GRT BSN/SW PLAINS WITH
THOUGHTS OF IMPACTING THE MIDWEST BY MID NEXT WEEK. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1151 PM CST SAT JAN 14 2012
.AVIATION...
LOW CLOUDS WITH MVFR TO VFR CIGS EXPECTED TO CONTINUE GRADUALLY
SHIFTING EWD OVRNGT AND EARLY SUN AM. AS CLOUDS THIN LATE
COULD SEE SOME MVFR FOG DEVELOP AT TERMINALS. GENERALLY EXPECTING
VFR CONDITIONS SUN WITH SLY WINDS BECOMING GUSTY AT 15-25 KTS
WITH LOCALLY HIGHER GUSTS POSSIBLE... AS PRESSURE GRADIENT TIGHTENS.
SOME MODEL GUIDANCE IS SHOWING LOW CLOUDS AND FOG WITH MVFR TO
IFR CONDITIONS DEVELOPING SUN EVE... BUT CONFIDENCE IS LOW. IN
ADDITION CONDITIONS APPEAR MORE FAVORABLE AT OR JUST BEYOND THE
END OF TAF CYCLE (06Z/16TH). DUE TO LOW CONFIDENCE HAVE GONE WITH
A MENTION OF SOME LOW CLOUDS WITH MVFR BASES BUT LEFT OUT CIGS.
SLY WINDS TO DIMINISH SOMEWHAT BUT REMAIN GUSTY AT 10-20 KTS.
&&
.PREV DISCUSSION... /ISSUED 330 PM CST SAT JAN 14 2012/
SYNOPSIS...
A COUPLE OF CLIPPER TYPE SYSTEMS WERE RESPONSIBLE FOR SOME LIGHT
SNOW OVER THE REGION THIS MORNING AND THIS AFTERNOON. THE SURFACE
LOW ASSOCIATED WITH ONE OF THE SYSTEM PASSED JUST TO OUR SOUTH THIS
MORNING SPREADING SOME LIGHT SNOW OVER THE SOUTHERN COUNTIES.
ANOTHER LOW WAS MOVING THOUGH NORTHERN MN EARLY THIS AFTERNOON WITH
A WARM FRONT EXTENDING SOUTH INTO WESTERN IOWA. SOME LIGHT SNOW AND
FLURRIES WERE OCCURRING JUST AHEAD OF THE FRONT. THE CLIPPER TYPE
SYSTEMS WERE EMBEDDED IN NORTHWEST FLOW BOUNDED BY A LARGE TROF OVER
THE GREAT LAKES AND OHIO VALLEY AND RIDGING OVER THE ROCKIES.
ANOTHER VIGOROUS S/W WAS MOVING INTO BRITISH COLUMBIA AND THE
PACIFIC NW WITH 200 METER 12 HOUR HEIGHT FALLS NOTED ON THE MORNING
500MB ANALYSIS.
SHORT TERM...TONIGHT AND SUNDAY...
THE NORTHERN MN LOW AND ITS ASSOCIATED WARM FRONT WEAKEN THIS
EVENING AS LOW LEVEL FLOW OVER THE CENTRAL AND NORTHERN PLAINS
BACKS AHEAD OF THE PACIFIC NW S/W AND ITS STRONGER SURFACE LOW
MOVING INTO SOUTHERN SASKATCHEWAN BY SUNDAY MORNING. THE LIGHT
SNOW AHEAD OF THE WARM FRONT HAS BEEN STEADILY WEAKENING AS IT
MOVED OVER CENTRAL IOWA THIS AFTERNOON. THE CONTINUATION OF THIS
WEAKENING TREND IS SUPPORTED BY LOW/MID LEVEL FGEN DECREASING
OVER IA AND BECOMING MORE FOCUSED TO OUR NORTH THIS EVENING.
RECENT HRRR RUNS ALSO SUPPORT A BETTER THREAT OF MEASURABLE SNOW
NORTH OF THE CWFA. HAVE CUT POPS BACK TO SLIGHT CHANCE AT MOST...AND
LIMITED THOSE TO THE NORTHEAST THIRD OF THE FORECAST AREA FOR THIS
EVENING. AFTER MIDNIGHT EXPECT PARTLY TO MOSTLY CLOUDY SKIES WITH
MID LEVEL WAA ADVECTION CLOUDS MOVING THROUGH THE AREA AS WELL AS
SOME CI SPREADING IN WITH THE FORECAST AREA IN THE VICINITY OF THE
RIGHT ENTRANCE REGION OF AN H3 JET STREAK FROM MN/WI INTO NRN IN
AT 12Z SUNDAY. SOME FLURRIES WERE CONSIDERED IN THE WEST WITH THE
MID LEVEL WAA...BUT PRESSURE CONDENSATION DEFICITS WERE QUITE HIGH
BELOW 400MB...SO OPTED NOT TO MENTION FLURRIES. TEMPERATURES WILL
BE DIFFICULT WITH THE SNOW COVER...LIGHT WINDS AND PATCHY NATURE
OF THE CLOUDS. ANY CLEARING WILL ALLOW TEMPERATURES TO PLUMMET
OVER THE NORTH. LATEST TIMING OF THE CENTRAL IA CLOUDS INTO/THROUGH
THE CWFA SUGGEST THEY WILL NOT REACH THE EASTERN COUNTIES UNTIL A FEW
HOURS AFTER SUNSET SO ALLOWED FOR A SIGNIFICANT DROP EARLY THIS
EVENING IN NW IL WITH MINS IN THE SINGLE DIGITS.
SUNDAY THE REGION WILL BE DOMINATED BY SOUTHERLY FLOW IN THE LOW
LEVELS AS THE NORTHERN PLAINS SURFACE LOW TRACKS ALONG THE CANADIAN
BORDER AND DRY WESTERLY MID LEVEL FLOW. THIS SHOULD GIVE THE REGION
PLENTY OF SUN. KEPT TEMPERATURES IN THIS REGIME JUST ABOVE GUIDANCE
IN THE SOUTH WHERE LITTLE SNOW COVER EXISTS WITH HIGHS IN THE LOW
40S. OVER THE SNOW COVERED NORTH WENT WITH HIGHS IN THE 30S.
DLF..
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
SUNDAY NIGHT AND MONDAY...LATEST SUITE OF 12Z RUN MODELS IN
GENERALLY GOOD AGREEMENT THIS PERIOD OF SUGGESTING LEAD IMPULSE OF
PACIFIC NW WAVE ENERGY/SEEN CURRENTLY ON WATER VAPOR IMAGERY
ROTATING DOWN ALONG THE B.C. COAST/ TO RIDGE-RIDE NORTH OF THE U.S.
BORDER ACRS SOUTHERN CANADA AND ACRS JAMES BAY INTO MON. ASSOCIATED
SFC FRONT OFF THIS PASSING WAVE PROBABLY TO JUST MAKE IT ACRS
THE FAR NORTHWESTERN CWA BY 12Z...THUS PRE-FRONTAL WAA AND SOME
BOUNDARY LAYER MOISTURE INCREASE LATE AT NIGHT TO PRODUCE A STEADY
TO SLOW TEMP RISE TOWARD DAWN AND LOWS WILL BE FROM MID EVENING
THROUGH 3 AM CST. 50+ KT SOUTHWESTERLY LLJ TO REALLY WAA AND
PRODUCE A WARM WEDGE/INVERSION ALOFT IN THE H85-H7 MB LAYER BY
MONDAY. LIKE PREVIOUS SHIFT STATED...HIGHER DPTS ADVECTED IN AS
WELL AS SOME SNOW MELT JUICED BL TRAPPED UNDER BUILDING INVERSION TO
INDUCE LLVL STRATUS AND FOG LATE SUNDAY NIGHT INTO MON. STILL SOME
QUESTION ON SPEED OF THIS DEVELOPING/MOISTURE INCREASE AND SOME
RECENT SIGNALS OF THE LOW CLOUDS AND FOG REALLY DEVELOPING MORE
CLOSER TO MONDAY MORNING AS OPPOSED TO SUNDAY NIGHT. BUT WILL KEEP
FOG MENTION SUN NIGHT AND MONDAY. INCREASING LIFT AND MID LEVELS
REMAINING DRY ALOFT SUGGEST DRIZZLE GETTING WRUNG OUT OF THIS LLVL
CLOUD DECK...AND IF SFC TEMPS CAN/T CLIMB ABOVE FREEZING TIL DAWN
MONDAY...MAY BE SOME TROUBLE WITH FREEZING DRIZZLE ALONG AND
NORTH OF I-80 FRO AWHILE AND WILL MENTION IN THE ZONES. LOW CLOUDS
AND LLVL SATURATION MAY LIMIT SFC HEATING ENOUGH TO KEEP TEMPS AT
OR BELOW FREEZING UNTIL MID MON MORNING NORTH OF THE HWY 30 AREAS
AND WILL EXTEND FREEZING DRIZZLE MENTION IN THESE AREAS FOR MON
MORNING. FOG TO CONTINUE WELL INTO MON AS WELL. AS SFC BOUNDARY
SAGS AND STALLS OUT ACRS THE CWA PARALLEL TO MEAN SOUTHWESTERLY
STEERING FLOW ON MON...CONTINUED LLVL MOISTURE TRANSPORT AND
CONVERGENCE INTO THIS FEATURE MAY INCREASE/SATURATE MOISTURE
PROFILES DEEP ENOUGH FOR MORE OF A LIGHT RAIN FORMING ACRS MUCH OF
THE SOUTHEAST TWO THIRDS OF THE DVN CWA BY LATE MORNING AND INTO THE
AFTERNOON. THICK LLVL CLOUDS...FOG...SNOW MELT PROCESS...AND
SATURATION MAY LIMIT SFC HEATING WITH HIGHS MORE IN THE MID TO UPPER
30S IN THE SOUTH HALF AS OPPOSED TO MODEL GUIDANCE UPPER 30S TO LOWER
40S. TEMPS MAY ACTUALLY HAVE TROUBLE WARMING ABOVE 32 IN THE FAR
NORTHERN CWA/NORTH OF CID IA TO FREEPORT IL/ WHICH COULD EXTEND A
FREEZING DRIZZLE OR VERY LIGHT FREEZING RAIN SCENARIO WELL INTO THE
AFTERNOON IN THOSE AREAS. APPROACH OF MAIN UPPER TROF FROM THE
PACIFIC NW AND ACRS THE PLAINS COULD INDUCE SOME LLVL WAVE
DEVELOPMENT ALONG ON THE FRONT WHICH COULD EXTEND SOME PRECIP ALMOST
DEF ZONE STYLE IN THE EASTERN CWA MONDAY EVENING. WITH TOP-DOWN
COOLING AND SATURATION TAKING PLACE...THE RAIN COULD SWITCH OVER TO A
MIX OR ALL SNOW WITHIN A FEW HOURS AFTER SUNSET WITH SOME LIGHT
SLUSHY ACCUMULATION ALONG THE EASTERN I-80 CORRIDOR. TEMPS TO CRASH
LATE MON NIGHT INTO TUE MORNING IN LLVL COLD CONVEYOR WITH VALUES
RANGING FROM THE MID TEENS IN THE NORTHWEST...TO THE MID 20S IN THE
FAR EAST AND SOUTHEAST.
TUESDAY AND WEDNESDAY...THE LLVL CYCLONE REALLY TAKES OFF/DEEPENS
ACRS THE CENTRAL GRT LKS ON TUE...BUT THE BRUNT OF THE PASSING UPPER
TROF ACRS THE LOCAL AREA STILL TO PROBABLY TO MAKE FOR WIDESPREAD
LIGHT SNOWS ACRS MOST OF THE DVN CWA THROUGH LATE TUE AFTERNOON
BEFORE THE UPPER TROF AXIS PASSES ACRS LK MI BY TUE EVENING AND
SUBSIDENCE TAKES OVER IN ITS WAKE. POTENTIAL FOR SOME 1-2 INCH
AMOUNTS BY TUE EVENING MAINLY ALONG AND NORTH OF THE HWY 30
CORRIDOR...BUT MORE OF A STORY WILL BE THE COLD AND NORTHWESTERLY
SFC WINDS GUSTING UP OVER 30 MPH AT TIMES WITH WIND CHILLS NEAR
ZERO IN THE AFTERNOON. CLEARING AND COLD CONDITIONS TUE NIGHT WITH
PASSING LLVL RIDGE LOBE...SOME LOWS BELOW ZERO POSSIBLE IN AREAS
NORTH OF I80. PASSING CLIPPER ACRS MN/WI IN FRESHLY ESTABLISHED BROAD
NORTH-WESTERLIES...MAY USHER YET ANOTHER FRONT INTO THE CWA BY LATE
WED NIGHT WITH POSSIBLE FLURRIES.
THURSDAY THROUGH SATURDAY...LLVL BAROCLINICITY TO GET ALIGNED
PARALLEL UNDER THESE MEAN FLOW NORTH-WESTERLIES ACRS THE CWA ON
THU...AND ANY PASSING WAVE ALOFT IN THE PROGRESSIVE FLOW COULD WRING
OUT SOME LIGHT SNOW OR FLURRIES ALONG THE LLVL THERMAL RIBBON ON THU
AND WILL CARRY LOW CHC POPS FOR THIS POTENTIAL. BOTH THE 12Z RUN
GFS AND ECMWF NOW PICK UP ON A MORE SUBSTANTIAL TYPE CLIPPER-LIKE
WAVE PROPAGATING DOWN IN THIS FLOW ALONG THE BAROCLINICITY WHICH
UTILIZES SOME GULF MOISTURE FEED FROM THE SOUTH TO PRODUCE 1-3 OR
EVEN 2-4 INCHES OF SNOW ACRS THE NORTH HALF OF THE DVN CWA FROM LATE
THU NIGHT INTO FRI MORNING. WILL KEEP CHC POPS GOING FOR SNOW ON FRI
FOR NOW...AND MAYBE A MIX OF RAIN AND SNOW IN THE SOUTH WITH PRE-
SYSTEM WARM DRAW ALOFT POSSIBLE. FLATTENING FLOW AND POST-SYSTEM
RIDGING MAY BRING A LULL IN THE ACTION FOR LATER FRI NIGHT AND SAT.
SOME SIGNS OF ENOUGH WAA ON SAT AHEAD OF TE NEXT DEVELOPING LARGE
SYSTEM TO DRIVE TEMPS INTO THE MID TO UPPER 30S DEPENDING ON SNOW
COVER BY THAT TIME. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1100 AM MST SUN JAN 15 2012
.SYNOPSIS...
257 AM MST SUN JAN 15 2012
LATEST SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOWED
NORTHWESTERLY UPPER LEVEL FLOW TURNING TO THE WEST AS AN UPPER
LEVEL RIDGE MOVES OVER THE CENTRAL PLAINS. AT THE SURFACE A TROUGH
OF LOW PRESSURE WAS PROGRESSING EAST ACROSS THE TRI-STATE
AREA...CAUSING THE SOUTHWEST WINDS TO SHIFT TO THE WEST BEHIND IT.
JTL
&&
.SHORT TERM (TODAY-TUESDAY)...
257 AM MST SUN JAN 15 2012
MAIN FOCUS WILL BE SNOWFALL CHANCES WITH THE COLD FRONT ON MONDAY
AND MONDAY NIGHT.
TODAY AND TONIGHT...AN UPPER LEVEL RIDGE WILL BUILD INTO THE
TRI-STATE AREA TODAY. TONIGHT A COLD FRONT WILL MOVE THROUGH DURING
THE OVERNIGHT HOURS AHEAD OF AN UPPER LEVEL TROUGH THAT WILL MOVE
THROUGH MONDAY NIGHT. A SHALLOW LAYER OF MOISTURE WILL DEVELOP AS
THE COOLER AIR MOVES INTO THE AREA...CAUSING SOME CLOUDS TO
DEVELOP.
MONDAY...MOISTURE AND LIFT BEGIN TO MOVE INTO THE AREA FROM THE
NORTHWEST AHEAD OF THE UPPER LEVEL TROUGH DURING THE LATE
AFTERNOON...ALLOWING FOR SOME SLIGHT CHANCES FOR SNOWFALL FOR
MAINLY YUMA COUNTY.
MONDAY NIGHT...MOISTURE AND LIFT WILL MOVE OVER MOST OF THE AREA.
MODELS CONTINUE TO INDICATE THE BEST LIFT WILL GENERALLY BE AHEAD OF
THE BULK OF THE MOISTURE...WITH THE BEST COLLOCATION OF LIFT AND
MOISTURE DURING THE EVENING HOURS MAINLY NORTH OF HIGHWAY 24.
INCLUDED PRECIP. CHANCES FOR THE ENTIRE AREA DUE TO SOME
UNCERTAINTY IN THE TIMING AND STRENGTH OF THE LIFT AS IT MOVES
THROUGH. OVERNIGHT THE SNOWFALL LOOKS TO COME TO AN END FROM WEST
TO EAST AS THE UPPER LEVEL TROUGH MOVES THROUGH THE AREA. THE HILL
CITY AND NORTON AREAS MAY SEE SOME SNOW DURING THE OVERNIGHT HOURS...WITH
THE REST OF THE AREA LIKELY TO SEE SOME FLURRIES AS THE UPPER
LEVEL TROUGH MOVES EAST OUT OF THE AREA. WITH THE SREF CON TINING
TO PLACE THE BETTER CHANCES OVER NORTHERN NEBRASKA AND THE
MOISTURE MOVING IN BEHIND THE MAIN AREA OF LIFT...WILL CONTINUE
WITH LIGHT TOTAL SNOWFALL ACCUMULATIONS OF AN INCH OR LESS. MODELS
ALSO UNSURE OF THE STRENGTH OF THE WINDS AS THE SURFACE LOW MOVES
THROUGH DURING THE NIGHT. TRENDED THE WINDS TOWARD THE STRONGER
SOLUTIONS AS NAM AND GFS MSL PRESSURE PLOTS SHOW A STRONG GRADIENT
OVER THE AREA AS THE LOW MOVES THROUGH.
TUESDAY DRIER AIR AND A SURFACE HIGH PRESSURE MOVE INTO THE AREA.
HIGH TEMPERATURES FOR THE PERIOD WILL BE THE WARMEST TODAY. EASTERN
COLORADO WILL HAVE NEAR RECORD TEMPERATURES TODAY. THERE ARE SOME
CLOUDS MOVING IN FROM THE NORTHWEST...SO THESE WILL HAVE SOME AFFECT
ON HOW WARM TEMPERATURES WILL BE FOR THE WESTERN AREAS. MONDAY
TEMPERATURES WILL BE NEAR TO BELOW NORMAL AS COOLER AIR COMES IN
FROM THE NORTHEAST. THE CHEYENNE WELLS TO LEOTI AREA MAY HAVE
TEMPERATURES NEAR 50 IF THE FRONT DOES NOT MOVE THROUGH UNTIL LATE
AFTERNOON. TUESDAY TEMPERATURES WILL BE BELOW NORMAL.
LOW TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL TONIGHT AS THE COOLER
AIR BEGINS TO MOVE IN. MONDAY NIGHT LOWS WILL BE IN THE LOWER TO
MID TEENS AS BRISK NORTH WINDS CONTINUE TO BRING COOLER AIR INTO THE
AREA. TUESDAY NIGHT TEMPERATURES WILL BE NEAR NORMAL DESPITE THE
MOSTLY CLEAR SKIES AND DRY AIR.
JTL
.LONG TERM (WEDNESDAY-SATURDAY)...
257 AM MST SUN JAN 15 2012
NORTHWEST FLOW WILL PREVAIL ACROSS THE CENTRAL PLAINS THROUGH
FRIDAY. UPPER FLOW TRANSITIONS TO SOUTHWEST FLOW SATURDAY AS A
TROUGH DIGS INTO THE PACIFIC NORTHWEST. A SURFACE TROUGH WILL
PERSIST OVER EASTERN COLORADO THROUGH THURSDAY NIGHT AND THEN
SHIFT EAST FRIDAY. ANOTHER TROUGH WILL MOVE INTO EASTERN COLORADO
SATURDAY. DISTURBANCES COME THROUGH THE FLOW BUT LACK OF MOISTURE
WILL KEEP POPS NIL. MAX TEMPERATURES WILL RANGE FROM THE MID 40S
WEDNESDAY TO THE MID/UPPER 50S SATURDAY. MIN TEMPERATURES WILL
RANGE FROM THE MID/UPPER 20S WEDNESDAY NIGHT TO LOWER 30S SATURDAY
NIGHT.
FS
&&
.AVIATION...
1057 AM MST SUN JAN 15 2012
FOR THE 18Z TAF...VFR CONDITIONS WILL PREVAIL AT BOTH KGLD AND
KMCK THROUGH THE EFFECTIVE PERIOD. WINDS WILL BE GENERALLY LIGHT
AND VARIABLE BEFORE A COLD FRONT MOVES THROUGH THE REGION AROUND
06Z. NOT EXPECTING MUCH OF AN INCREASE IN WIND SPEEDS AT KGLD BUT
COULD SEE WINDS APPROACH 12KTS OUT OF THE NORTH-NORTHEAST AT KMCK
BEHIND THE FRONT. LITTLE MORE THAN A BAND OF MID/UPPER LEVEL
CLOUDS TO DEAL WITH THROUGH THE NEXT 24 HOURS.
FOLTZ
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1145 AM CST SUN JAN 15 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE (TODAY AND MONDAY)...
09Z WATER VAPOR IMAGERY AND RUC ANALYSIS INDICATES TWO UPPER TROUGHS
OVER THE CONUS. ONE IS LOCATED ROUGHLY OVER THE NEW ENGLAND
STATES..WITH THE OTHER JUST COMING ON SHORE OVER THE PACIFIC
NORTHWEST. BETWEEN THESE TWO TROUGHS IS A FLEETING UPPER RIDGE WHICH
WILL TRANSIT ACROSS THE AREA THROUGH THE DAY TODAY. STRONG SOUTHERLY
WINDS WILL PICK UP IN INTENSITY TODAY IN RESPONSE TO A NORTH-SOUTH
ELONGATED SURFACE TROUGH WHICH WILL MOVE OFF THE NORTHERN ROCKIES
TODAY. EXPECT THE SOUTHERLY WINDS TO REACH THE 20 TO 30 MPH
RANGE...WITH GUSTS OF UP TO 35 MPH. WARM AIR ADVECTION ASSOCIATED
WITH THE SOUTHERLY FLOW IN CONJUNCTION WITH THE QUICKLY MOVING
RIDGE WILL BRING A CLEAR AND UNSEASONABLY WARM DAY TO NORTHEAST
KANSAS. EXPECT ONLY SHALLOW MIXING TODAY WITH A STRONG INVERSION
EXPECTED TO SET UP NEAR THE 925 MB LEVEL...BUT DRY AIR JUST OFF
THE SURFACE WILL BE ALLOWED TO MIX TO THE SURFACE CAUSING DRY
CONDITIONS TODAY...LENDING TO AN ENHANCED FIRE DANGER TODAY. WILL
NEED TO CONTINUE TO MONITOR THE CONDITIONS AS THE DAY WEARS ON AND
MAKE ADJUSTMENTS TO THE FORECAST AS NECESSARY.
THE WARM UP WILL NOT LAST LONG AS A STRONG COLD FRONT WILL MOVE INTO
THE AREA ON MONDAY EVENING. PORTIONS OF EAST CENTRAL KANSAS WILL
LIKELY SEE ANOTHER DAY OF UPPER 50 TO LOWER 60 DEGREE TEMPS ON
MONDAY AS THOSE AREAS WILL REMAIN AHEAD OF THE COLD FRONT. AREAS
BEHIND THE FRONT...NAMELY AREAS NORTH AND WEST OF THE KANSAS
TURNPIKE...WILL LIKELY ONLY SEE HIGHS IN THE LOWER TO MID 40S ON
MONDAY. ON MONDAY NIGHT THE PARENT MID TO UPPER LEVEL TROUGH WILL
PASS THROUGH THE NORTHERN PLAINS...CAUSING THE MOST SIGNIFICANT LIFT
TO REMAIN NORTH OF THE KS/NE BORDER. WITH THE MARGINAL LIFT AND DRY
AIR OVER NORTHEAST KANSAS DO NOT EXPECT VERY MUCH PRECIPITATION FROM
THIS SYSTEM. THE AREA WITH THE BEST CHANCE FOR ANY PRECIP ON MONDAY
NIGHT WILL BE EXTREME NORTH CENTRAL AND NORTHEASTERN KANSAS...MAINLY
ALONG HIGHWAY 36...BUT EVEN THESE AREAS ARE NOT EXPECTED TO SEE MUCH
MORE THAN SOME FLURRIES OR OCCASIONAL LIGHT SNOW WITH LITTLE TO NO
ACCUMULATION EXPECTED.
MID RANGE AND EXTENDED FORECAST (TUESDAY THROUGH SATURDAY)...
BY TUESDAY STRONG NORTHERLY WINDS OF 20 TO 30 MPH WILL USHER IN
ANOTHER ARCTIC AIR MASS INTO THE THE CENTRAL PLAINS. WITH THE COLD
AIR BECOMING FIRMLY ENTRENCHED OVER THE AREA EXPECT TEMPS ON TUESDAY
TO MAX OUT IN THE UPPER 20S TO LOWER 30S ACROSS ALL OF NORTHEAST
KANSAS. WEDNESDAY NIGHT WILL LIKELY BE THE COLDEST PERIOD OF THIS
FORECAST AS THE SURFACE RIDGE BECOMES CENTERED OVER THE AREAS
CAUSING THE OVERNIGHT LOWS TO FALL TO THE LOWER TO MID TEENS. BY WED
ANOTHER BRIEF WARM UP IS EXPECTED AS SOUTH-SOUTHWEST WINDS BRING WARM
AIR BACK INTO THE AREA. EXPECT ANOTHER MILD DAY ON WED WITH TEMPS
MAXING OUT IN THE MID TO UPPER 40S. EXPECT THE GRADUAL WARM UP TO
CONTINUE THROUGH THE END OF THE WEEK BRINGING MILD CONDITIONS TO THE
AREA.
JL
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
.AVIATION...
VFR CONDITIONS CURRENTLY ACROSS THE TERMINALS AND WILL CONTINUE
INTO THE OVERNIGHT HOURS. STRONG SOUTH TO SOUTHWEST WIND WILL
CONTINUE THIS AFTERNOON. LLWS COULD BE A CONCERN WITH WINDS AROUND
50 KTS AT 2 KFT AFTER 00Z TONIGHT. HOWEVER...WITH UNIDIRECTIONAL
FLOW UP TO 2 KFT DID NOT INCLUDE IN TAF. LOW LEVEL MOISTURE WILL
INCREASE AHEAD OF THE FRONT WITH MVFR CEILINGS MOVING INTO KTOP AND
KFOE AROUND 08Z.
ANDERSON
&&
.FIRE WEATHER...
EXPECT SOUTHERLY WINDS TODAY TO INCREASE TO 15 TO 25 MPH WITH
GUSTS OF UP TO 35 MPH. EXPECT THE STRONGEST WINDS TO BE ACROSS
AREAS EAST OF A MARYSVILLE TO COUNCIL GROVE LINE...HOWEVER EVEN
AREAS WEST OF THIS LINE COULD SEE WINDS OF 15 TO 25 MPH TODAY.
MIXING WILL BE FAIRLY SHALLOW ON SUNDAY...HOWEVER THE SOUTHERLY
WINDS WILL ADVECT AIR FROM ACROSS SOUTHERN MISSOURI...EASTERN
OKLAHOMA...AND WESTERN ARKANSAS NORTHWARD INTO EASTERN KANSAS.
CURRENTLY THE DEWPOINTS OF THIS AIRMASS ARE IN THE LOWER TO MID 20
DEGREE RANGE...SO FEEL THAT DEWPOINTS ACROSS THE AREA WILL NOT
REACH MUCH HIGHER THAN 25 DEGREES...WHICH IN COMBINATION WITH THE
LOWER 60 DEGREE AIR WILL YIELD MIN RH VALUES IN THE LOWER TO MID
20 PERCENT RANGE FOR THIS AFTERNOON. AS A RESULT OF THESE
CONDITIONS VERY HIGH FIRE DANGER WILL EXIST ACROSS PARTS OF THE
AREA FOR TODAY. CONDITIONS WILL NEED TO BE MONITORED THROUGHOUT
THE DAY IN CASE THE AIR DRIES OUT MORE THAN EXPECTED.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
554 AM CST SUN JAN 15 2012
...UPDATE TO AVIATION...
.AVIATION...
VFR CONDITIONS EXPECTED WITH LLWS LIKELY THE MAIN ISSUE FOR MOST
OF THE FORECAST PERIOD. WINDS PROGGED TO START TO RELAX IN THE
AFTERNOON INTO THE OVERNIGHT HOURS AND REMAIN SOUTHERLY. FRONT
APPROACHES FROM THE NORTH OUTSIDE THE TAF PERIOD. 67
&&
.FIRE WEATHER...
EXPECT SOUTHERLY WINDS TODAY TO INCREASE TO 15 TO 25 MPH WITH
GUSTS OF UP TO 35 MPH. EXPECT THE STRONGEST WINDS TO BE ACROSS
AREAS EAST OF A MARYSVILLE TO COUNCIL GROVE LINE...HOWEVER EVEN
AREAS WEST OF THIS LINE COULD SEE WINDS OF 15 TO 25 MPH TODAY.
MIXING WILL BE FAIRLY SHALLOW ON SUNDAY...HOWEVER THE SOUTHERLY
WINDS WILL ADVECT AIR FROM ACROSS SOUTHERN MISSOURI...EASTERN
OKLAHOMA...AND WESTERN ARKANSAS NORTHWARD INTO EASTERN KANSAS.
CURRENTLY THE DEWPOINTS OF THIS AIRMASS ARE IN THE LOWER TO MID 20
DEGREE RANGE...SO FEEL THAT DEWPOINTS ACROSS THE AREA WILL NOT
REACH MUCH HIGHER THAN 25 DEGREES...WHICH IN COMBINATION WITH THE
LOWER 60 DEGREE AIR WILL YIELD MIN RH VALUES IN THE LOWER TO MID
20 PERCENT RANGE FOR THIS AFTERNOON. AS A RESULT OF THESE
CONDITIONS VERY HIGH FIRE DANGER WILL EXIST ACROSS PARTS OF THE
AREA FOR TODAY. CONDITIONS WILL NEED TO BE MONITORED THROUGHOUT
THE DAY IN CASE THE AIR DRIES OUT MORE THAN EXPECTED.
JL
&&
.PREV DISCUSSION...
/ISSUED 407 AM CST SUN JAN 15 2012/
SHORT RANGE (TODAY AND MONDAY)...
09Z WATER VAPOR IMAGERY AND RUC ANALYSIS INDICATES TWO UPPER TROUGHS
OVER THE CONUS. ONE IS LOCATED ROUGHLY OVER THE NEW ENGLAND
STATES..WITH THE OTHER JUST COMING ON SHORE OVER THE PACIFIC
NORTHWEST. BETWEEN THESE TWO TROUGHS IS A FLEETING UPPER RIDGE WHICH
WILL TRANSIT ACROSS THE AREA THROUGH THE DAY TODAY. STRONG SOUTHERLY
WINDS WILL PICK UP IN INTENSITY TODAY IN RESPONSE TO A NORTH-SOUTH
ELONGATED SURFACE TROUGH WHICH WILL MOVE OFF THE NORTHERN ROCKIES
TODAY. EXPECT THE SOUTHERLY WINDS TO REACH THE 20 TO 30 MPH
RANGE...WITH GUSTS OF UP TO 35 MPH. WARM AIR ADVECTION ASSOCIATED
WITH THE SOUTHERLY FLOW IN CONJUNCTION WITH THE QUICKLY MOVING
RIDGE WILL BRING A CLEAR AND UNSEASONABLY WARM DAY TO NORTHEAST
KANSAS. EXPECT ONLY SHALLOW MIXING TODAY WITH A STRONG INVERSION
EXPECTED TO SET UP NEAR THE 925 MB LEVEL...BUT DRY AIR JUST OFF
THE SURFACE WILL BE ALLOWED TO MIX TO THE SURFACE CAUSING DRY
CONDITIONS TODAY...LENDING TO AN ENHANCED FIRE DANGER TODAY. WILL
NEED TO CONTINUE TO MONITOR THE CONDITIONS AS THE DAY WEARS ON AND
MAKE ADJUSTMENTS TO THE FORECAST AS NECESSARY.
THE WARM UP WILL NOT LAST LONG AS A STRONG COLD FRONT WILL MOVE INTO
THE AREA ON MONDAY EVENING. PORTIONS OF EAST CENTRAL KANSAS WILL
LIKELY SEE ANOTHER DAY OF UPPER 50 TO LOWER 60 DEGREE TEMPS ON
MONDAY AS THOSE AREAS WILL REMAIN AHEAD OF THE COLD FRONT. AREAS
BEHIND THE FRONT...NAMELY AREAS NORTH AND WEST OF THE KANSAS
TURNPIKE...WILL LIKELY ONLY SEE HIGHS IN THE LOWER TO MID 40S ON
MONDAY. ON MONDAY NIGHT THE PARENT MID TO UPPER LEVEL TROUGH WILL
PASS THROUGH THE NORTHERN PLAINS...CAUSING THE MOST SIGNIFICANT LIFT
TO REMAIN NORTH OF THE KS/NE BORDER. WITH THE MARGINAL LIFT AND DRY
AIR OVER NORTHEAST KANSAS DO NOT EXPECT VERY MUCH PRECIPITATION FROM
THIS SYSTEM. THE AREA WITH THE BEST CHANCE FOR ANY PRECIP ON MONDAY
NIGHT WILL BE EXTREME NORTH CENTRAL AND NORTHEASTERN KANSAS...MAINLY
ALONG HIGHWAY 36...BUT EVEN THESE AREAS ARE NOT EXPECTED TO SEE MUCH
MORE THAN SOME FLURRIES OR OCCASIONAL LIGHT SNOW WITH LITTLE TO NO
ACCUMULATION EXPECTED.
MID RANGE AND EXTENDED FORECAST (TUESDAY THROUGH SATURDAY)...
BY TUESDAY STRONG NORTHERLY WINDS OF 20 TO 30 MPH WILL USHER IN
ANOTHER ARCTIC AIR MASS INTO THE THE CENTRAL PLAINS. WITH THE COLD
AIR BECOMING FIRMLY ENTRENCHED OVER THE AREA EXPECT TEMPS ON TUESDAY
TO MAX OUT IN THE UPPER 20S TO LOWER 30S ACROSS ALL OF NORTHEAST
KANSAS. WEDNESDAY NIGHT WILL LIKELY BE THE COLDEST PERIOD OF THIS
FORECAST AS THE SURFACE RIDGE BECOMES CENTERED OVER THE AREAS
CAUSING THE OVERNIGHT LOWS TO FALL TO THE LOWER TO MID TEENS. BY WED
ANOTHER BRIEF WARM UP IS EXPECTED AS SOUTH-SOUTHWEST WINDS BRING WARM
AIR BACK INTO THE AREA. EXPECT ANOTHER MILD DAY ON WED WITH TEMPS
MAXING OUT IN THE MID TO UPPER 40S. EXPECT THE GRADUAL WARM UP TO
CONTINUE THROUGH THE END OF THE WEEK BRINGING MILD CONDITIONS TO THE
AREA.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
412 AM MST SUN JAN 15 2012
.SYNOPSIS...
LATEST SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOWED
NORTHWESTERLY UPPER LEVEL FLOW TURNING TO THE WEST AS AN UPPER
LEVEL RIDGE MOVES OVER THE CENTRAL PLAINS. AT THE SURFACE A TROUGH
OF LOW PRESSURE WAS PROGRESSING EAST ACROSS THE TRI-STATE
AREA...CAUSING THE SOUTHWEST WINDS TO SHIFT TO THE WEST BEHIND IT.
JTL
&&
.SHORT TERM (TODAY-TUESDAY)...
257 AM MST SUN JAN 15 2012
MAIN FOCUS WILL BE SNOWFALL CHANCES WITH THE COLD FRONT ON MONDAY
AND MONDAY NIGHT.
TODAY AND TONIGHT...AN UPPER LEVEL RIDGE WILL BUILD INTO THE
TRI-STATE AREA TODAY. TONIGHT A COLD FRONT WILL MOVE THROUGH DURING
THE OVERNIGHT HOURS AHEAD OF AN UPPER LEVEL TROUGH THAT WILL MOVE
THROUGH MONDAY NIGHT. A SHALLOW LAYER OF MOISTURE WILL DEVELOP AS
THE COOLER AIR MOVES INTO THE AREA...CAUSING SOME CLOUDS TO
DEVELOP.
MONDAY...MOISTURE AND LIFT BEGIN TO MOVE INTO THE AREA FROM THE
NORTHWEST AHEAD OF THE UPPER LEVEL TROUGH DURING THE LATE
AFTERNOON...ALLOWING FOR SOME SLIGHT CHANCES FOR SNOWFALL FOR
MAINLY YUMA COUNTY.
MONDAY NIGHT...MOISTURE AND LIFT WILL MOVE OVER MOST OF THE AREA.
MODELS CONTINUE TO INDICATE THE BEST LIFT WILL GENERALLY BE AHEAD OF
THE BULK OF THE MOISTURE...WITH THE BEST COLLOCATION OF LIFT AND
MOISTURE DURING THE EVENING HOURS MAINLY NORTH OF HIGHWAY 24.
INCLUDED PRECIP. CHANCES FOR THE ENTIRE AREA DUE TO SOME
UNCERTAINTY IN THE TIMING AND STRENGTH OF THE LIFT AS IT MOVES
THROUGH. OVERNIGHT THE SNOWFALL LOOKS TO COME TO AN END FROM WEST
TO EAST AS THE UPPER LEVEL TROUGH MOVES THROUGH THE AREA. THE HILL
CITY AND NORTON AREAS MAY SEE SOME SNOW DURING THE OVERNIGHT HOURS...WITH
THE REST OF THE AREA LIKELY TO SEE SOME FLURRIES AS THE UPPER
LEVEL TROUGH MOVES EAST OUT OF THE AREA. WITH THE SREF CON TINING
TO PLACE THE BETTER CHANCES OVER NORTHERN NEBRASKA AND THE
MOISTURE MOVING IN BEHIND THE MAIN AREA OF LIFT...WILL CONTINUE
WITH LIGHT TOTAL SNOWFALL ACCUMULATIONS OF AN INCH OR LESS. MODELS
ALSO UNSURE OF THE STRENGTH OF THE WINDS AS THE SURFACE LOW MOVES
THROUGH DURING THE NIGHT. TRENDED THE WINDS TOWARD THE STRONGER
SOLUTIONS AS NAM AND GFS MSL PRESSURE PLOTS SHOW A STRONG GRADIENT
OVER THE AREA AS THE LOW MOVES THROUGH.
TUESDAY DRIER AIR AND A SURFACE HIGH PRESSURE MOVE INTO THE AREA.
HIGH TEMPERATURES FOR THE PERIOD WILL BE THE WARMEST TODAY. EASTERN
COLORADO WILL HAVE NEAR RECORD TEMPERATURES TODAY. THERE ARE SOME
CLOUDS MOVING IN FROM THE NORTHWEST...SO THESE WILL HAVE SOME AFFECT
ON HOW WARM TEMPERATURES WILL BE FOR THE WESTERN AREAS. MONDAY
TEMPERATURES WILL BE NEAR TO BELOW NORMAL AS COOLER AIR COMES IN
FROM THE NORTHEAST. THE CHEYENNE WELLS TO LEOTI AREA MAY HAVE
TEMPERATURES NEAR 50 IF THE FRONT DOES NOT MOVE THROUGH UNTIL LATE
AFTERNOON. TUESDAY TEMPERATURES WILL BE BELOW NORMAL.
LOW TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL TONIGHT AS THE COOLER
AIR BEGINS TO MOVE IN. MONDAY NIGHT LOWS WILL BE IN THE LOWER TO
MID TEENS AS BRISK NORTH WINDS CONTINUE TO BRING COOLER AIR INTO THE
AREA. TUESDAY NIGHT TEMPERATURES WILL BE NEAR NORMAL DESPITE THE
MOSTLY CLEAR SKIES AND DRY AIR.
JTL
.LONG TERM (WEDNESDAY-SATURDAY)...
257 AM MST SUN JAN 15 2012
NORTHWEST FLOW WILL PREVAIL ACROSS THE CENTRAL PLAINS THROUGH
FRIDAY. UPPER FLOW TRANSITIONS TO SOUTHWEST FLOW SATURDAY AS A
TROUGH DIGS INTO THE PACIFIC NORTHWEST. A SURFACE TROUGH WILL
PERSIST OVER EASTERN COLORADO THROUGH THURSDAY NIGHT AND THEN
SHIFT EAST FRIDAY. ANOTHER TROUGH WILL MOVE INTO EASTERN COLORADO
SATURDAY. DISTURBANCES COME THROUGH THE FLOW BUT LACK OF MOISTURE
WILL KEEP POPS NIL. MAX TEMPERATURES WILL RANGE FROM THE MID 40S
WEDNESDAY TO THE MID/UPPER 50S SATURDAY. MIN TEMPERATURES WILL
RANGE FROM THE MID/UPPER 20S WEDNESDAY NIGHT TO LOWER 30S SATURDAY
NIGHT.
FS
&&
.AVIATION...
412 AM MST SUN JAN 15 2012
FOR THE 12Z TAFS...VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24
HOURS AT KGLD AND KMCK. SOME HIGH CLOUDS WILL PASS OVER THE
TERMINALS OCCASIONALLY AND WINDS WILL GENERALLY BE LIGHT FROM THE
SOUTHWEST TURNING TO THE NORTHEAST BEHIND THE FRONT AT KMCK EARLY
SUNDAY MORNING.
FS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
316 AM MST SUN JAN 15 2012
.SYNOPSIS...
LATEST SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOWED
NORTHWESTERLY UPPER LEVEL FLOW TURNING TO THE WEST AS AN UPPER
LEVEL RIDGE MOVES OVER THE CENTRAL PLAINS. AT THE SURFACE A TROUGH
OF LOW PRESSURE WAS PROGRESSING EAST ACROSS THE TRI-STATE
AREA...CAUSING THE SOUTHWEST WINDS TO SHIFT TO THE WEST BEHIND IT.
JTL
&&
.SHORT TERM (TODAY-TUESDAY)...
257 AM MST SUN JAN 15 2012
MAIN FOCUS WILL BE SNOWFALL CHANCES WITH THE COLD FRONT ON MONDAY
AND MONDAY NIGHT.
TODAY AND TONIGHT...AN UPPER LEVEL RIDGE WILL BUILD INTO THE
TRI-STATE AREA TODAY. TONIGHT A COLD FRONT WILL MOVE THROUGH DURING
THE OVERNIGHT HOURS AHEAD OF AN UPPER LEVEL TROUGH THAT WILL MOVE
THROUGH MONDAY NIGHT. A SHALLOW LAYER OF MOISTURE WILL DEVELOP AS
THE COOLER AIR MOVES INTO THE AREA...CAUSING SOME CLOUDS TO
DEVELOP.
MONDAY...MOISTURE AND LIFT BEGIN TO MOVE INTO THE AREA FROM THE
NORTHWEST AHEAD OF THE UPPER LEVEL TROUGH DURING THE LATE
AFTERNOON...ALLOWING FOR SOME SLIGHT CHANCES FOR SNOWFALL FOR
MAINLY YUMA COUNTY.
MONDAY NIGHT...MOISTURE AND LIFT WILL MOVE OVER MOST OF THE AREA.
MODELS CONTINUE TO INDICATE THE BEST LIFT WILL GENERALLY BE AHEAD OF
THE BULK OF THE MOISTURE...WITH THE BEST COLLOCATION OF LIFT AND
MOISTURE DURING THE EVENING HOURS MAINLY NORTH OF HIGHWAY 24.
INCLUDED PRECIP. CHANCES FOR THE ENTIRE AREA DUE TO SOME
UNCERTAINTY IN THE TIMING AND STRENGTH OF THE LIFT AS IT MOVES
THROUGH. OVERNIGHT THE SNOWFALL LOOKS TO COME TO AN END FROM WEST
TO EAST AS THE UPPER LEVEL TROUGH MOVES THROUGH THE AREA. THE HILL
CITY AND NORTON AREAS MAY SEE SOME SNOW DURING THE OVERNIGHT HOURS...WITH
THE REST OF THE AREA LIKELY TO SEE SOME FLURRIES AS THE UPPER
LEVEL TROUGH MOVES EAST OUT OF THE AREA. WITH THE SREF CON TINING
TO PLACE THE BETTER CHANCES OVER NORTHERN NEBRASKA AND THE
MOISTURE MOVING IN BEHIND THE MAIN AREA OF LIFT...WILL CONTINUE
WITH LIGHT TOTAL SNOWFALL ACCUMULATIONS OF AN INCH OR LESS. MODELS
ALSO UNSURE OF THE STRENGTH OF THE WINDS AS THE SURFACE LOW MOVES
THROUGH DURING THE NIGHT. TRENDED THE WINDS TOWARD THE STRONGER
SOLUTIONS AS NAM AND GFS MSL PRESSURE PLOTS SHOW A STRONG GRADIENT
OVER THE AREA AS THE LOW MOVES THROUGH.
TUESDAY DRIER AIR AND A SURFACE HIGH PRESSURE MOVE INTO THE AREA.
HIGH TEMPERATURES FOR THE PERIOD WILL BE THE WARMEST TODAY. EASTERN
COLORADO WILL HAVE NEAR RECORD TEMPERATURES TODAY. THERE ARE SOME
CLOUDS MOVING IN FROM THE NORTHWEST...SO THESE WILL HAVE SOME AFFECT
ON HOW WARM TEMPERATURES WILL BE FOR THE WESTERN AREAS. MONDAY
TEMPERATURES WILL BE NEAR TO BELOW NORMAL AS COOLER AIR COMES IN
FROM THE NORTHEAST. THE CHEYENNE WELLS TO LEOTI AREA MAY HAVE
TEMPERATURES NEAR 50 IF THE FRONT DOES NOT MOVE THROUGH UNTIL LATE
AFTERNOON. TUESDAY TEMPERATURES WILL BE BELOW NORMAL.
LOW TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL TONIGHT AS THE COOLER
AIR BEGINS TO MOVE IN. MONDAY NIGHT LOWS WILL BE IN THE LOWER TO
MID TEENS AS BRISK NORTH WINDS CONTINUE TO BRING COOLER AIR INTO THE
AREA. TUESDAY NIGHT TEMPERATURES WILL BE NEAR NORMAL DESPITE THE
MOSTLY CLEAR SKIES AND DRY AIR.
JTL
.LONG TERM (WEDNESDAY-SATURDAY)...
257 AM MST SUN JAN 15 2012
NORTHWEST FLOW WILL PREVAIL ACROSS THE CENTRAL PLAINS THROUGH
FRIDAY. UPPER FLOW TRANSITIONS TO SOUTHWEST FLOW SATURDAY AS A
TROUGH DIGS INTO THE PACIFIC NORTHWEST. A SURFACE TROUGH WILL
PERSIST OVER EASTERN COLORADO THROUGH THURSDAY NIGHT AND THEN
SHIFT EAST FRIDAY. ANOTHER TROUGH WILL MOVE INTO EASTERN COLORADO
SATURDAY. DISTURBANCES COME THROUGH THE FLOW BUT LACK OF MOISTURE
WILL KEEP POPS NIL. MAX TEMPERATURES WILL RANGE FROM THE MID 40S
WEDNESDAY TO THE MID/UPPER 50S SATURDAY. MIN TEMPERATURES WILL
RANGE FROM THE MID/UPPER 20S WEDNESDAY NIGHT TO LOWER 30S SATURDAY
NIGHT.
FS
&&
.AVIATION...
1010 PM MST SAT JAN 14 2012
SURFACE HIGH PRESSURE WILL SLIDE INTO THE EASTERN CONUS AS A LEE
TROUGH DEVELOPS AND DEEPENS TO OUR WEST. IN THE UPPER
LEVELS...HIGH PRESSURE RIDGE WILL MOVE OVER THE AREA THIS PERIOD
WITH A TROUGH MOVING INTO THE INTERMOUNTAIN WEST. VFR CONDITIONS
ARE EXPECTED DURING THIS PERIOD WITH HIGH CIRRUS MOVING OVER THE
AREA FROM TIME TO TIME. SURFACE WINDS WILL BE FROM THE SOUTHWEST
EARLY THEN SWITCHING TO THE WEST. TOWARDS THE END OF THE
PERIOD...WINDS WILL BECOME LIGHT AND VARIABLE AS THE PRESSURE
GRADIENT WEAKENS.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
407 AM CST SUN JAN 15 2012
.DISCUSSION...
SHORT RANGE (TODAY AND MONDAY)...
09Z WATER VAPOR IMAGERY AND RUC ANALYSIS INDICATES TWO UPPER TROUGHS
OVER THE CONUS. ONE IS LOCATED ROUGHLY OVER THE NEW ENGLAND
STATES..WITH THE OTHER JUST COMING ON SHORE OVER THE PACIFIC
NORTHWEST. BETWEEN THESE TWO TROUGHS IS A FLEETING UPPER RIDGE WHICH
WILL TRANSIT ACROSS THE AREA THROUGH THE DAY TODAY. STRONG SOUTHERLY
WINDS WILL PICK UP IN INTENSITY TODAY IN RESPONSE TO A NORTH-SOUTH
ELONGATED SURFACE TROUGH WHICH WILL MOVE OFF THE NORTHERN ROCKIES
TODAY. EXPECT THE SOUTHERLY WINDS TO REACH THE 20 TO 30 MPH
RANGE...WITH GUSTS OF UP TO 35 MPH. WARM AIR ADVECTION ASSOCIATED
WITH THE SOUTHERLY FLOW IN CONJUNCTION WITH THE QUICKLY MOVING
RIDGE WILL BRING A CLEAR AND UNSEASONABLY WARM DAY TO NORTHEAST
KANSAS. EXPECT ONLY SHALLOW MIXING TODAY WITH A STRONG INVERSION
EXPECTED TO SET UP NEAR THE 925 MB LEVEL...BUT DRY AIR JUST OFF
THE SURFACE WILL BE ALLOWED TO MIX TO THE SURFACE CAUSING DRY
CONDITIONS TODAY...LENDING TO AN ENHANCED FIRE DANGER TODAY. WILL
NEED TO CONTINUE TO MONITOR THE CONDITIONS AS THE DAY WEARS ON AND
MAKE ADJUSTMENTS TO THE FORECAST AS NECESSARY.
THE WARM UP WILL NOT LAST LONG AS A STRONG COLD FRONT WILL MOVE INTO
THE AREA ON MONDAY EVENING. PORTIONS OF EAST CENTRAL KANSAS WILL
LIKELY SEE ANOTHER DAY OF UPPER 50 TO LOWER 60 DEGREE TEMPS ON
MONDAY AS THOSE AREAS WILL REMAIN AHEAD OF THE COLD FRONT. AREAS
BEHIND THE FRONT...NAMELY AREAS NORTH AND WEST OF THE KANSAS
TURNPIKE...WILL LIKELY ONLY SEE HIGHS IN THE LOWER TO MID 40S ON
MONDAY. ON MONDAY NIGHT THE PARENT MID TO UPPER LEVEL TROUGH WILL
PASS THROUGH THE NORTHERN PLAINS...CAUSING THE MOST SIGNIFICANT LIFT
TO REMAIN NORTH OF THE KS/NE BORDER. WITH THE MARGINAL LIFT AND DRY
AIR OVER NORTHEAST KANSAS DO NOT EXPECT VERY MUCH PRECIPITATION FROM
THIS SYSTEM. THE AREA WITH THE BEST CHANCE FOR ANY PRECIP ON MONDAY
NIGHT WILL BE EXTREME NORTH CENTRAL AND NORTHEASTERN KANSAS...MAINLY
ALONG HIGHWAY 36...BUT EVEN THESE AREAS ARE NOT EXPECTED TO SEE MUCH
MORE THAN SOME FLURRIES OR OCCASIONAL LIGHT SNOW WITH LITTLE TO NO
ACCUMULATION EXPECTED.
MID RANGE AND EXTENDED FORECAST (TUESDAY THROUGH SATURDAY)...
BY TUESDAY STRONG NORTHERLY WINDS OF 20 TO 30 MPH WILL USHER IN
ANOTHER ARCTIC AIR MASS INTO THE THE CENTRAL PLAINS. WITH THE COLD
AIR BECOMING FIRMLY ENTRENCHED OVER THE AREA EXPECT TEMPS ON TUESDAY
TO MAX OUT IN THE UPPER 20S TO LOWER 30S ACROSS ALL OF NORTHEAST
KANSAS. WEDNESDAY NIGHT WILL LIKELY BE THE COLDEST PERIOD OF THIS
FORECAST AS THE SURFACE RIDGE BECOMES CENTERED OVER THE AREAS
CAUSING THE OVERNIGHT LOWS TO FALL TO THE LOWER TO MID TEENS. BY WED
ANOTHER BRIEF WARM UP IS EXPECTED AS SOUTH-SOUTHWEST WINDS BRING WARM
AIR BACK INTO THE AREA. EXPECT ANOTHER MILD DAY ON WED WITH TEMPS
MAXING OUT IN THE MID TO UPPER 40S. EXPECT THE GRADUAL WARM UP TO
CONTINUE THROUGH THE END OF THE WEEK BRINGING MILD CONDITIONS TO THE
AREA.
JL
&&
.AVIATION...
VFR CONDITIONS SHOULD HOLD THROUGH 06Z SUNDAY. WILL GO AHEAD WITH
LLWS MENTION IN THE 09Z-18Z PERIOD GIVEN QUICK INCREASES WITH
HEIGHT PER MODEL SOUNDINGS AND WINDS INCREASING IN UPSTREAM
PROFILERS. MAY HAVE LLWS RETURN BY 03Z MONDAY BUT TOO SOON TO
NAIL DOWN. ONLY SOME CIRRUS EXPECTED.
65
&&
.FIRE WEATHER...
EXPECT SOUTHERLY WINDS TODAY TO INCREASE TO 15 TO 25 MPH WITH
GUSTS OF UP TO 35 MPH. EXPECT THE STRONGEST WINDS TO BE ACROSS
AREAS EAST OF A MARYSVILLE TO COUNCIL GROVE LINE...HOWEVER EVEN
AREAS WEST OF THIS LINE COULD SEE WINDS OF 15 TO 25 MPH TODAY.
MIXING WILL BE FAIRLY SHALLOW ON SUNDAY...HOWEVER THE SOUTHERLY
WINDS WILL ADVECT AIR FROM ACROSS SOUTHERN MISSOURI...EASTERN
OKLAHOMA...AND WESTERN ARKANSAS NORTHWARD INTO EASTERN KANSAS.
CURRENTLY THE DEWPOINTS OF THIS AIRMASS ARE IN THE LOWER TO MID 20
DEGREE RANGE...SO FEEL THAT DEWPOINTS ACROSS THE AREA WILL NOT
REACH MUCH HIGHER THAN 25 DEGREES...WHICH IN COMBINATION WITH THE
LOWER 60 DEGREE AIR WILL YIELD MIN RH VALUES IN THE LOWER TO MID
20 PERCENT RANGE FOR THIS AFTERNOON. AS A RESULT OF THESE
CONDITIONS VERY HIGH FIRE DANGER WILL EXIST ACROSS PARTS OF THE
AREA FOR TODAY. CONDITIONS WILL NEED TO BE MONITORED THROUGHOUT
THE DAY IN CASE THE AIR DRIES OUT MORE THAN EXPECTED.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1011 PM MST SAT JAN 14 2012
.UPDATE...
959 PM MST SAT JAN 14 2012
JUST COMPLETED AN UPDATE. TIGHTER GRADIENT/LOW LEVEL JET HAS SET
UP OVER THE WESTERN PORTION OF THE AREA WITH WINDS NOW IN THE
BREEZY TO WINDY CATEGORY. THE LATEST RUC CATCHES ONTO THIS...AND
USED TO UPDATE THE WINDS. WITH THE WINDS STAYING UP STRONGER THAN
EXPECTED RAISED MINS A FEW DEGREES.
BULLER
&&
.DISCUSSION...
200 PM MST SAT JAN 14 2012
TONIGHT...QUIET WEATHER WILL PREVAIL THROUGH THE OVERNIGHT HOURS
WITH A GENERALLY CLEAR SKY. SOUTHWESTERLY WINDS WILL BECOME MORE
WESTERLY LATE TONIGHT AS A WEAK SURFACE TROUGH SLIDES THROUGH THE
AREA. OVERNIGHT TEMPS SHOULD GENERALLY BE IN THE MID 20S WHICH IS
AROUND 10 DEGREES ABOVE NORMAL.
FOLTZ
SUNDAY-TUESDAY NIGHT...TEMPERATURES IN THE UPPER 50S TO NEAR 65
EXPECTED SUNDAY (RECORD/NEAR RECORD HIGH POSSIBLE IN YUMA...63 IN
2006) AHEAD OF A COLD FRONT THAT MOVES THROUGH SUNDAY NIGHT.
DIFFERING SOLUTIONS AS TO WHETHER OR NOT THE FRONT CAN MOVE
THROUGH THE SOUTHWEST PORTIONS OF THE AREA WHERE IT MAY BECOME
STATIONARY TIL MONDAY AFTERNOON WHEN AN UPPER LEVEL DISTURBANCE
WITHIN NORTHWEST FLOW ALOFT MOVES THROUGH. AS IT DOES AM EXPECTING
THE FRONT TO THEN CLEAR THE AREA. 850 TEMPERATURES AS WELL AS
MOS/MAV AND BETTER OF LATE BIAS CORRECTED GRIDS WOULD SUPPORT
HIGHS IN THE 30S FOR ALL BUT THE WEST/SOUTHWEST PARTS OF THE AREA
MONDAY WHERE AHEAD OF THE FRONT HIGHS IN THE LOW TO MID 40S
EXPECTED.
AS FOR PRECIPITATION CHANCES...NAM/ECWMF IN BETTER AGREEMENT WHEN
COMPARED TO THE GFS (SLIGHTLY SLOWER) WITH REGARDS TO ARRIVAL AND
DEPARTURE OF ABOVE MENTIONED UPPER DISTURBANCE AND MOISTURE
ASSOCIATED WITH IT MONDAY NIGHT. GIVEN THE FAST FLOW ALOFT SHOULD
SEE ONLY A FEW TENTHS OF AN INCH OF SNOW FROM THIS SYSTEM. THINK
IT WILL ONLY BE A 6 HOUR OR SO EVENT BUT GIVEN THE TIMING
DIFFERENCES DECIDED TO EXTEND IT FOR THE ENTIRE NIGHT AND WILL
AWAIT FUTURE MODEL RUNS TO HOPEFULLY PIN IT DOWN A BIT BETTER.
SHOULD SEE LOTS OF SUN TUESDAY WITH WINDS GENERALLY UNDER 10 MPH.
BELOW NORMAL AFTERNOON HIGHS EXPECTED WITH MID 30S ACROSS THE
AREA. OVERNIGHT LOWS THROUGH THE PERIOD NOT FAR OFF FROM NORMAL.
WEDNESDAY THROUGH SATURDAY...FORECAST AREA TO REMAIN UNDER
NORTHWEST FLOW ALOFT. DRY THROUGH FRIDAY NIGHT WITH A SPOTTY
SLIGHT CHANCE FOR LIGHT RAIN SATURDAY AND A LITTLE BETTER CHANCE
EARLY SATURDAY NIGHT AS A WEATHER DISTURBANCE MOVES THROUGH.
TEMPERATURES THROUGH THE PERIOD START IN THE 40S
WEDNESDAY...QUICKLY WARMING INTO THE 50S THURSDAY-SATURDAY. MAY
SEE SOME 60S THURSDAY-SATURDAY...ESPECIALLY ALONG AND WEST OF THE
CO/KS BORDER PER 850 TEMPERATURES (AND MEX GUIDANCE) BUT FOR NOW
GIVEN GOOD AGREEMENT WITH SURROUNDING OFFICES WILL NOT MAKE ANY
CHANGES.
07
&&
.AVIATION...
1010 PM MST SAT JAN 14 2012
SURFACE HIGH PRESSURE WILL SLIDE INTO THE EASTERN CONUS AS A LEE
TROUGH DEVELOPS AND DEEPENS TO OUR WEST. IN THE UPPER
LEVELS...HIGH PRESSURE RIDGE WILL MOVE OVER THE AREA THIS PERIOD
WITH A TROUGH MOVING INTO THE INTERMOUNTAIN WEST. VFR CONDITIONS
ARE EXPECTED DURING THIS PERIOD WITH HIGH CIRRUS MOVING OVER THE
AREA FROM TIME TO TIME. SURFACE WINDS WILL BE FROM THE SOUTHWEST
EARLY THEN SWITCHING TO THE WEST. TOWARDS THE END OF THE
PERIOD...WINDS WILL BECOME LIGHT AND VARIABLE AS THE PRESSURE
GRADIENT WEAKENS.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1210 AM EST SUN JAN 15 2012
...Mesoscale Update...
Well we`re down to a few lingering flurries and that`s about it.
Will continue the WSW for road conditions, but no more meaningful
snow is expected.
Sky cover will be a challenge overnight, and will have a significant
impact on temperatures. NAM12 and GFS40 show skies becoming mostly
clear overnight, as they move the clouds northwest Illinois due
east. However the HRRR develops a very low stratus deck right over
the LMK CWA and keeps it there through the night. Satellite loops
indeed show a developing low cloud deck over central Kentucky and
Fort Knox reported a few clouds at 600 feet on their 11pm
observation. So, will continue with high-end partly/low-end mostly
cloudy skies for tonight.
Even with some cloud cover, the 1 to 4 inches of brand new snow will
cause temperatures to fall easily. Have decreased lows in relation
to the amount of snow we received earlier this evening. As a result
from Meade County to Garrard and Lincoln counties we have lows
progged in the 12 to 16 degree range. If clouds become thicker than
forecast then these lows will not be realized, but there should be
enough breaks to allow temps to fall at least into the teens. Calm
winds associated with high pressure moving in from the lower
Mississippi Valley to be centered right over Kentucky at 12Z will
assist.
&&
.Short Term (Tonight and Sunday)...
Well, looks like water vapor imagery has a pretty potent
clipper/shortwave crossing the TN/KY border, and shortwave energy
extending back up through IA/MN. An associated surface low is
located near PAH at the moment, with light snow occurring anywhere
form central IL towards west-central KY. However, ground truth
reports indicate that a lack of boundary layer moisture is keeping
the light snow from really doing too much at the moment, but it is
starting to hit the ground finally in our western CWA as several
mesoscale models had indicated the strengthening overhead. Thus,
will keep the advisory going for the time being, but will likely be
able to cancel part of the counties by the forecast package time.
Really think we`d be fine with a Special Weather Statement, but will
at least give the advisory a chance for our easternmost counties
anyway. Upslope for the Bluegrass region south of 64 and the Lake
Cumberland region may help yield small accumulations most likely
less than an inch. Will send another quick AFD update if counties
are cancelled. At the very least, have trended back POPs to the
chance category through 00z.
Regardless of the light snow amounts if any, the clipper system
should be east of our CWA by around midnight, so have tapering POPs
from northwest to southeast tonight, ending in flurries by 06z. With
the surface low/clipper passage this evening, we could see brief
gusty winds on the back side of the low, with 1-2 hours of gusts up
to 25 knots possibly. Surface high pressure will quickly move in,
and towards dawn Sunday, winds will be light/variable. Look for
overnight lows ranging from the upper teens to lower 20s.
For Sunday, clearing behind the clipper will allow our temperatures
to climb into the mid to upper 30s in most spots, perhaps the lower
40s over the far southwest closest to the upper ridging.
.Long Term (Sunday Night - Saturday)...
Sunday Night - Tuesday Night...
Surface high pressure and slight ridging aloft will shift to the
east coast states by late Sunday. Surface winds will become
southerly, while winds aloft will favor southwesterly, especially by
Monday morning. A shortwave and associated surface low will pass by
to our north, with the surface low positioned across the southern
Great Lakes by Tuesday morning. A cold front will be stretched
southwestward from the Great Lakes through the mid Mississippi River
Valley. Southerly winds will become rather breezy to locally windy
by Monday afternoon as the pressure gradient strengthens between the
east coast high and this approaching area of low pressure.
Additionally, isentropic lift will increase across the area, and by
Monday afternoon we should see scattered rain showers build across
the forecast area. The greatest precipitation chances continue be in
the north and northwest Monday afternoon into the evening, closest
to the frontal boundary.
The cold front will begin to push into the forecast area late Monday
night and exit the southeast CWA early Tuesday afternoon. This will
provide the best chance of widespread rain showers and a few rumbles
of thunder, as moisture streams northward from the open Gulf. PWATs
are still on track to reach, and slightly exceed, the one inch mark,
which will supply about a half an inch to an inch of rainfall for
most locations. Most likely areas for the higher amounts would be
across the north and west, where Monday afternoon rainfall will add
to the rainfall total.
As for temperatures, southerly winds should aid the warming process
Monday, but cloud cover and precipitation chances in the afternoon
could put a stop to that. Either way, upper 40s across the north to
lower 50s across the south look good at this time. Tuesday morning
lows should be rather mild for this time of year, with generally mid
40s expected. Temperatures should warm some ahead of the front
Tuesday, but will drop off once the front passes. Will continue with
the non-diurnal temps, with the warmest locations being across the
south and east. For now, will go with mid and upper 40s across the
northwest, with low to mid 50s across the southeast for highs
Tuesday. Could see a rain snow mix on the back side of departing
precipitation if cold air works in fast enough. The 12Z GFS came in
a little warmer at the surface and aloft than previous runs.
However, will not make too many changes to the ongoing forecast of
rain/snow mix Tuesday afternoon and night because the NAM and SREF
data continue to show cooler temps arriving. Lows Tuesday night will
drop to the low to mid 20s.
Wednesday - Saturday...
Surface high pressure behind the cold front will quickly move east,
with southerly flow commencing by late Wednesday. Flow aloft will
transition from northwesterly Wednesday to basically zonal by
Friday. High temperatures in the low to mid 30s Wednesday will give
way to 50s by Saturday. A clipper system will pass by to our north
Thursday, while our next best chance of precipitation will arrive
near the weekend. Another area of low pressure is forecast to swing
into the Ohio Valley Friday through Saturday. Moisture does not look
all that impressive at this time, but rain chances will increase
Friday afternoon and continue into Saturday with the cold frontal
passage.
&&
.Aviation (06Z TAF Issuance)...
Clipper that caused this afternoon/evening`s snowfall is quickly
racing east into the Carolina`s and precipitation has ended across
the region. Main concern for the overnight is potential for low
stratus development as very low level moisture lingers and will
combine with increasingly subsident airmass as high pressure builds
in. Best chances for a window of IFR or below stratus deck will be
at LEX and SDF through the predawn hours, however will stay
optimistic that BWG remains VFR through the remainder of the
forecast. Otherwise, light northwest winds overnight will veer to
southeasterly between 5 and 10 mph this afternoon. High pressure at
the surface and aloft will keep the forecast VFR through the day.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
INZ090>092.
KY...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
KYZ025-028>031-034-038>041-045>049-054>057-066-067.
$$
Mesoscale........13
Short Term.......AL
Long Term........MJP
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1142 PM EST SAT JAN 14 2012
...Mesoscale Update...
Well we`re down to a few lingering flurries and that`s about it.
Will continue the WSW for road conditions, but no more meaningful
snow is expected.
Sky cover will be a challenge overnight, and will have a significant
impact on temperatures. NAM12 and GFS40 show skies becoming mostly
clear overnight, as they move the clouds northwest Illinois due
east. However the HRRR develops a very low stratus deck right over
the LMK CWA and keeps it there through the night. Satellite loops
indeed show a developing low cloud deck over central Kentucky and
Fort Knox reported a few clouds at 600 feet on their 11pm
observation. So, will continue with high-end partly/low-end mostly
cloudy skies for tonight.
Even with some cloud cover, the 1 to 4 inches of brand new snow will
cause temperatures to fall easily. Have decreased lows in relation
to the amount of snow we received earlier this evening. As a result
from Meade County to Garrard and Lincoln counties we have lows
progged in the 12 to 16 degree range. If clouds become thicker than
forecast then these lows will not be realized, but there should be
enough breaks to allow temps to fall at least into the teens. Calm
winds associated with high pressure moving in from the lower
Mississippi Valley to be centered right over Kentucky at 12Z will
assist.
&&
.Short Term (Tonight and Sunday)...
Well, looks like water vapor imagery has a pretty potent
clipper/shortwave crossing the TN/KY border, and shortwave energy
extending back up through IA/MN. An associated surface low is
located near PAH at the moment, with light snow occurring anywhere
form central IL towards west-central KY. However, ground truth
reports indicate that a lack of boundary layer moisture is keeping
the light snow from really doing too much at the moment, but it is
starting to hit the ground finally in our western CWA as several
mesoscale models had indicated the strengthening overhead. Thus,
will keep the advisory going for the time being, but will likely be
able to cancel part of the counties by the forecast package time.
Really think we`d be fine with a Special Weather Statement, but will
at least give the advisory a chance for our easternmost counties
anyway. Upslope for the Bluegrass region south of 64 and the Lake
Cumberland region may help yield small accumulations most likely
less than an inch. Will send another quick AFD update if counties
are cancelled. At the very least, have trended back POPs to the
chance category through 00z.
Regardless of the light snow amounts if any, the clipper system
should be east of our CWA by around midnight, so have tapering POPs
from northwest to southeast tonight, ending in flurries by 06z. With
the surface low/clipper passage this evening, we could see brief
gusty winds on the back side of the low, with 1-2 hours of gusts up
to 25 knots possibly. Surface high pressure will quickly move in,
and towards dawn Sunday, winds will be light/variable. Look for
overnight lows ranging from the upper teens to lower 20s.
For Sunday, clearing behind the clipper will allow our temperatures
to climb into the mid to upper 30s in most spots, perhaps the lower
40s over the far southwest closest to the upper ridging.
.Long Term (Sunday Night - Saturday)...
Sunday Night - Tuesday Night...
Surface high pressure and slight ridging aloft will shift to the
east coast states by late Sunday. Surface winds will become
southerly, while winds aloft will favor southwesterly, especially by
Monday morning. A shortwave and associated surface low will pass by
to our north, with the surface low positioned across the southern
Great Lakes by Tuesday morning. A cold front will be stretched
southwestward from the Great Lakes through the mid Mississippi River
Valley. Southerly winds will become rather breezy to locally windy
by Monday afternoon as the pressure gradient strengthens between the
east coast high and this approaching area of low pressure.
Additionally, isentropic lift will increase across the area, and by
Monday afternoon we should see scattered rain showers build across
the forecast area. The greatest precipitation chances continue be in
the north and northwest Monday afternoon into the evening, closest
to the frontal boundary.
The cold front will begin to push into the forecast area late Monday
night and exit the southeast CWA early Tuesday afternoon. This will
provide the best chance of widespread rain showers and a few rumbles
of thunder, as moisture streams northward from the open Gulf. PWATs
are still on track to reach, and slightly exceed, the one inch mark,
which will supply about a half an inch to an inch of rainfall for
most locations. Most likely areas for the higher amounts would be
across the north and west, where Monday afternoon rainfall will add
to the rainfall total.
As for temperatures, southerly winds should aid the warming process
Monday, but cloud cover and precipitation chances in the afternoon
could put a stop to that. Either way, upper 40s across the north to
lower 50s across the south look good at this time. Tuesday morning
lows should be rather mild for this time of year, with generally mid
40s expected. Temperatures should warm some ahead of the front
Tuesday, but will drop off once the front passes. Will continue with
the non-diurnal temps, with the warmest locations being across the
south and east. For now, will go with mid and upper 40s across the
northwest, with low to mid 50s across the southeast for highs
Tuesday. Could see a rain snow mix on the back side of departing
precipitation if cold air works in fast enough. The 12Z GFS came in
a little warmer at the surface and aloft than previous runs.
However, will not make too many changes to the ongoing forecast of
rain/snow mix Tuesday afternoon and night because the NAM and SREF
data continue to show cooler temps arriving. Lows Tuesday night will
drop to the low to mid 20s.
Wednesday - Saturday...
Surface high pressure behind the cold front will quickly move east,
with southerly flow commencing by late Wednesday. Flow aloft will
transition from northwesterly Wednesday to basically zonal by
Friday. High temperatures in the low to mid 30s Wednesday will give
way to 50s by Saturday. A clipper system will pass by to our north
Thursday, while our next best chance of precipitation will arrive
near the weekend. Another area of low pressure is forecast to swing
into the Ohio Valley Friday through Saturday. Moisture does not look
all that impressive at this time, but rain chances will increase
Friday afternoon and continue into Saturday with the cold frontal
passage.
&&
.Aviation (00Z TAF Issuance)...
Clipper centered over Nashville at 22Z will be in North Carolina by
midnight and will take the light snow with it. Light snow should be
ending at SDF in the first hour of the TAF and by 03 or 04Z at LEX,
with BWG remaining unaffected.
Ceilings will continue to be tricky overnight, with clouds
continuing to stream into the northern TAF sites especially. There
are a few MVFR ceilings upstream in Illinois but the great majority
of the CIGs are VFR so will go with that. Models do suggest that
lower CIGs will be possible, though, so will keep an eye on it.
High pressure will quickly move in behind the departing clipper this
evening and will remain overhead through Sunday morning. As a
result we could see some spotty fog again at BWG in the morning,
though will keep it MVFR for now.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR INZ090>092.
KY...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR
KYZ025-028>031-
034-038>041-045>049-054>057-066-067.
$$
Mesoscale........13
Short Term.......AL
Long Term........MJP
Aviation.........13
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
120 AM EST SUN JAN 15 2012
.SYNOPSIS...
GREAT LAKES LOW PRESSURE WILL PROVIDE FLURRIES UNTIL IT GIVES WAY
TO TENNESSEE HIGH PRESSURE LATER TODAY TO PROVIDE DRY CONDITIONS
INTO MONDAY MORNING. CANADIAN ROCKIES LOW PRESSURE WILL FIRST BRING
A WARM UP WITH RAIN SHOWERS LATE MONDAY AND TUESDAY, BUT THEN
DELIVER A COOL DOWN WITH SNOW SHOWERS TUESDAY NIGHT INTO WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT, CONTINUE TO
FORESEE A SNOW BAND MOVING SOUTH FROM CLEVELAND PROVIDING A CHANCE
OF SNOW SHOWERS FOR LOCATIONS NORTH OF I-70 UNTIL THE BAND
DISSIPATES TOWARD DAYBREAK. MORNING LOWS WILL BE ABOUT 10 DEGREES
COLDER THAN NORMAL.
RECENT SREF MODEL OUTPUT THEN SHOWS HIGH PRESSURE, COMING EAST
FROM TENNESSEE, TO PROVIDE SUFFICIENT SUBSIDENCE AFTER DAYBREAK TO
END ANY REMAINING FLURRIES AND TO CLEAR AWAY MOST CLOUDS BY
MIDDAY.
DESPITE AFTERNOON SUNSHINE, HAVE FORECASTED AFTERNOON HIGH
TEMPERATURES, BASED ON BLEND OF RECENT GFS AND NAM MOS, TO BE NO
WARMER THAN SATURDAY AND SOME 10 DEGREES COLDER THAN NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
BLEND OF RECENT SREF MODEL OUTPUT CONTINUES TO SHOW HIGH PRESSURE
MAINTAINING DRY CONDITIONS TONIGHT AND MONDAY MORNING. A LOW
PRESSURE SYSTEM, COMING EAST FROM ALBERTA, WILL PUSH A WARM FRONT
THROUGH THE UPPER OHIO VALLEY MONDAY NIGHT.
SO AFTER A COLD MORNING, WITH LOW TEMPERATURES ABOUT 5 DEGREES
COLDER THAN NORMAL, AFTERNOON HIGHS WILL REBOUND TO VALUES
SLIGHTLY WARMER THAN NORMAL. MORE IMPORTANTLY, THE WARM UP TO
TEMPERATURES WARMER THAN FREEZING ENSURES THE INITIAL
PRECIPITATION MONDAY AFTERNOON WILL BE RAIN SHOWERS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
DESPITE MODEL DIFFERENCES, CONSENSUS YIELDS COLD FRONTAL PASSAGE
WILL BE TUESDAY NIGHT. HENCE EXPECT MILD TEMPERATURES AND RAIN
SHOWERS MONDAY NIGHT AND DAYTIME TUESDAY, FOLLOWED BY A SHARP COOL
DOWN AND CHANGE TO SNOW SHOWERS TUESDAY NIGHT. POST SYSTEM
NORTHWEST FLOW MAY TAP ENOUGH GREAT LAKES MOISTURE FOR SNOW
SHOWERS TO LINGER INTO WEDNESDAY.
THE UPPER LEVEL JETSTREAM WILL REMAIN STRONG AND FAIRLY ZONAL INTO
THE WEEKEND, WHICH WILL PROMOTE FAST SYSTEM MOVEMENT. HENCE
LOW PRESSURE ZIPPING THROUGH THE GREAT LAKES TO PROVIDE A CHANCE
OF SNOW SHOWERS AGAIN THURSDAY AND A CHANCE OF RAIN AND SNOW
SHOWERS LATE FRIDAY.
KEPT TEMPERATURES CLOSE TO HPC GUIDANCE WITH TEMPERATURES ABOUT 5
DEGREES COLDER THAN NORMAL WEDNESDAY...MODERATING TO 5 DEGREES
WARMER THAN NORMAL FRIDAY AND PERHAPS TO 10 DEGREES WARMER THAN
NORMAL SATURDAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
PER RECENT SURFACE AND SATELLITE DATA, EXPECT VFR TO BE PREVALENT
THIS PERIOD. THE ONLY CAVEAT WILL BE THE INFLUENCE OF A DYING SNOW
BAND MOVING SOUTH FROM NORTHEAST OHIO, WHICH MAY PROVIDE A SHORT
PERIOD OF MVFR TIL ABOUT 10Z.
NAM MODEL PROFILES SHOW STRATOCUMULUS DISSIPATING THIS AFTERNOON
DUE TO HIGH PRESSURE SUBSIDENCE.
OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
VFR INTO MIDDAY MONDAY. THEN RESTRICTIONS DEVELOPING DUE TO WARM
FRONTAL SHOWERS LATE MONDAY INTO TUESDAY, AND COLD FRONTAL SNOW
SHOWERS TUESDAY NIGHT INTO WEDNESDAY. THERE CAN AGAIN BE
RESTRICTIONS THURSDAY DUE TO COLD FRONTAL SNOW SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
930 PM EST MON JAN 16 2012
LATEST UPDATE...SHORT TERM...
.SYNOPSIS...(400 PM EST MON JAN 16 2012)
LOW PRESSURE WILL TRACK FROM MISSOURI TO LAKE ONTARIO TONIGHT AND
TUESDAY. THIS SYSTEM WILL PRODUCE A WIDESPREAD 3 TO 6 INCH SNOWFALL
OVER NORTHERN LOWER MICHIGAN... AND A WINTRY MIX OF SNOW AND
FREEZING RAIN ACROSS CENTRAL LOWER MICHIGAN.
MEANWHILE RAIN AND AREAS OF FOG WILL IMPACT SOUTHERN LOWER MICHIGAN
TONIGHT. THE RAIN WILL CHANGE TO SNOW SHOWERS TUESDAY AFTERNOON ONCE
THE LOW PASSES BY AND COLDER AIR RUSHES IN. LAKE EFFECT SNOW SHOWERS
TUESDAY NIGHT COULD PRODUCE 1 TO 3 INCHES OF ADDITIONAL SNOW ALONG
AND WEST OF HIGHWAY 131.
MORE SNOW SHOWERS...WITH SOME ACCUMULATIONS...ARE ANTICIPATED
WEDNESDAY NIGHT AND THURSDAY AS THE NEXT COLD FRONT PUSHES THROUGH
THE REGION AND BRINGS A REINFORCING SHOT OF COLD ARCTIC AIR.
&&
.SHORT TERM...(930 PM EST MON JAN 16 2012)
(TONIGHT THROUGH WEDNESDAY AFTERNOON)
A DENSE FOG ADVISORY IS BEING ISSUED FOR THE OVERNIGHT PERIOD
THROUGH MID MORNING TUESDAY FOR ROUGHLY THE SOUTHERN HALF OF OUR
FCST AREA. A COUPLE OF OBS SITES ARE REPORTING VISBY DOWN TO A
QUARTER MILE AND MOST OTHER OBS SITES ACROSS OUR SOUTHERN FCST AREA
ARE SHOWING A SLOW BUT STEADY TREND DOWNWARD WITH VISBYS. SHORT
RANGE GUIDANCE SUCH AS THE 13KM RUC SUGGESTS FOG WILL ONLY BECOME
MORE DENSE/WIDESPREAD OVERNIGHT AND THIS MAKES PHYSICAL SENSE GIVEN
HIGH BOUNDARY LAYER MOISTURE AND TEMPS RIGHT AT OR NEAR THE DEW PT.
REMAINDER OF PREVIOUS SHORT TERM FCST DISCUSSION FOLLOWS...HAVE
ISSUED A WINTER WEATHER ADVISORY FOR THE NRN CWFA FOR LATE
TONIGHT AND TUESDAY FOR A MIXTURE OF SNOW AND FREEZING RAIN CHANGING
TO ALL SNOW. AM THINKING 3-5 INCHES OF SYNOPTIC SNOWS NORTH OF A
LINE FROM ROUGHLY HART TO CLARE WHERE PCPN WILL BE MOSTLY SNOW. JUST
SOUTH OF THERE.... INCLUDING BIG RAPIDS... MT PLEASANT AND ALMA...
WILL FCST 1 TO 3 INCHES OF SNOW WITH UP TO A TENTH OF AN INCH OF
FREEZING RAIN.
MODELS INSIST THAT LIGHT RAIN/DRIZZLE WILL RAPIDLY DEVELOP EARLY
THIS EVENING IN RESPONSE TO TIGHTENING FRONTAL ZONE OVERHEAD AND
APPROACHING SHORTWAVE. FORTUNATELY TEMPERATURES HAVE WARMED ABOVE 40
IN MOST AREAS AND FREEZING RAIN WILL NOT BE A THREAT TO START OUT.
HOWEVER LATER THIS EVENING THE FAR NRN CWFA MAY COOL BACK DOWN TO
NEAR FREEZING...WITH A MUCH BETTER RISK OF FALLING BELOW FREEZING
VERY LATE TONIGHT AS THE LOW LEVEL NE FLOW DEVELOPS/STRENGTHENS ON
THE NORTH SIDE OF THE STRENGTHENING FRONTAL ZONE.
THE BULK OF THE EVENT OCCURS ON TUESDAY WHEN THE DEFORMATION ZONE
IMPACTS THE REGION. PRIOR TO THAT THE MOISTURE IS RATHER SHALLOW AND
THE DGZ IS NOT SATURATED. BEST OMEGA/DGZ COMBINATION SETS UP ACROSS
THE NW CWFA AROUND LDM. MEANWHILE BECAUSE OF THE SFC LOW TRACK...
PROGS SHOW COLD AIR TAKING IT/S TIME ARRIVING IN THE SE CWFA AROUND
JXN ON TUESDAY. IT TAKES UNTIL AFTER 18Z-21Z TO COOL SUFFICIENTLY TO
SUPPORT SNOW. THUS WILL FCST UNDER AN INCH OF ACCUM FROM LAN SOUTH.
THE LAKE EFFECT ON TUESDAY NIGHT LOOKS FAIRLY SHORT LIVED AS SURFACE
RIDGING AND LOWERING INVERSION HEIGHTS ARRIVE AFTER 06Z. HOWEVER
SOME QUICK ADDITIONAL 1-4 INCH ACCUMULATIONS ARE CERTAINLY POSSIBLE
ALONG/WEST OF HWY 131 PRIOR TO THE LATE NIGHT DIMINISHING TREND.
WEDNESDAY LOOKS QUIET AS SHORTWAVE RIDGING IMPACTS THE REGION IN
BETWEEN SYSTEMS.
&&
.LONG TERM...(400 PM EST MON JAN 16 2012)
(WEDNESDAY NIGHT THROUGH MONDAY)
A CLIPPER IS GOING TO BRING ANOTHER SHOT OF ARCTIC AIR TO THE
REGION. LIKE PREVIOUS COLD AIR INTRUSIONS...THIS ONE WON/T LAST LONG
EITHER...A COUPLE OF DAYS. SHORT RANGE MODELS SHOW THE COLD FRONT
MOVING ACROSS THE CWA WEDNESDAY NIGHT. WE/LL SEE SHSN DEVELOP ALONG
AND BEHIND THE COLD FRONT. WE HAVE LIKELY POPS OVER THE WRN CWA WED
NIGHT AND THURSDAY. WE SHOULD SEE SEVERAL INCHES OF ACCUMULATIONS IN
THE USUAL NW SNOW BELT AREAS AS H8 -20C AIR MOVES ACROSS THE LAKE.
INVERSION HEIGHTS FALL DURING THE DAY AND NIGHT BEFORE SW FLOW WAA
FRIDAY BRINGS IN SOME MORE MOISTURE. WSW FLOW LAKE ENHANCED FLOW
WILL MEAN ACCUMULATING SNOW POSSIBLE AGAIN FRIDAY. H8 TEMPS WARM
ENOUGH FRIDAY NIGHT/SATURDAY SUCH THAT LAKE EFFECT SNOW SHOULD STOP.
WAA CONTINUES INTO SUNDAY WHERE TEMPS SHOULD CLIMB ABOVE 40 AGAIN
AHEAD OF THE NEXT CLIPPER SUNDAY NIGHT. MIXED RAIN/SNOW SUNDAY INTO
MONDAY AS THE CLIPPER AND TRAILING COLD FRONT MOVE THROUGH. THERE
DOESN/T APPEAR TO BE A STRONG SURGE OF ARCTIC AIR BEHIND THE SUNDAY
CLIPPER.
&&
.AVIATION...(646 PM EST MON JAN 16 2012)
EXPECT IFR/LIFR CIGS AND VSBY MOST OF TONIGHT AND THROUGH MOST OF
TUESDAY. DRIZZLE...LIGHT RAIN AND FOG WILL PREVAIL MOST OF THE
NIGHT. PRECIPITATION WILL CHANGE TO SNOW DURING THE MID DAY HOURS OF
TUESDAY THEN THE SNOW WILL CONTINUE THROUGH THE AFTERNOON.
THE LOWEST CIGS AND VSBY WILL BE AS THE SURFACE LOW TRACKS BETWEEN
INTERSTATE 94 AND INTERSTATE 96 DURING THE EARLY TO MID MORNING
HOURS OF TUESDAY (THAT IS WHEN THE WIND WILL BE LIGHTEST). ONCE THE
SURFACE LOW IS EAST OF THE AREA WINDS WILL KICK UP OUT OF THE
NORTHWEST AND BRING IN THE COLD AIR. SOME FREEZING RAIN IS POSSIBLE
DURING THE TRANSITION FROM RAIN TO SNOW FOR NOW I PUT THAT ONLY AT
MKG BUT IT IS POSSIBLE AT GRR AND LAN TOO.
&&
.MARINE...(400 PM EST MON JAN 16 2012)
WILL LET THE SMALL CRAFT ADVISORY EXPIRE AT 4 PM... BUT ISSUE A
GALE WARNING FOR TUESDAY DUE TO STRONG NW FLOW ON THE BACK SIDE OF
THE DEPARTING SYSTEM.
&&
.HYDROLOGY...(400 PM EST MON JAN 16 2012)
NO ICE JAMS HAVE BEEN REPORTED... BUT WILL MONITOR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL 11 AM TUESDAY FOR MUSKEGON...
OTTAWA... KENT... IONIA... CLINTON... ALLEGAN... BARRY...
EATON... INGHAM... VAN BUREN... KALAMAZOO... CALHOUN
AND JACKSON COUNTIES.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
TUESDAY FOR MASON LAKE OSCEOLA CLARE OCEANA NEWAYGO MECOSTA
ISABELLA MONTCALM AND GRATIOT COUNTIES.
LM...GALE WARNING ST JOSEPH TO MANISTEE TUESDAY INTO TUESDAY
EVENING... 7 AM TO 11 PM.
&&
$$
SYNOPSIS: MEADE
SHORT TERM: MEADE/LAURENS
LONG TERM: 93
AVIATION: WDM
MARINE: MEADE
HYDROLOGY: MEADE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
640 PM EST MON JAN 16 2012
UPDATED AVIATION DISCUSSION FOR THE 00Z TAFS
.SYNOPSIS... ISSUED AT 433 PM EST
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW GENERAL WRN TROF/
ERN RDG PATTERN ACRS NAMERICA. THERE IS A STRONG DISTURBANCE/120KT
H3 JET MAX IN ONTARIO EMBEDDED WITHIN THE WSW FLOW ALF...AND
ATTENDANT COLD FNT IS PRESSING TOWARD WRN UPR MI EARLY THIS AFTN.
THERE IS QUITE A BIT OF LO CLD IN THE RELATIVELY MILD SSW FLOW AHEAD
OF THIS FNT WITH 12Z GRB RAOB SHOWING THIN SATURATED LYR ARND
H925...BUT MID LVL DRYNESS SHOWN ON THAT RAOB IS PREVENTING ANY
PCPN. TEMPS DROP OFF SHARPLY BEHIND THE APRCHG COLD FNT WITH
READINGS OVER THE MN ARROWHEAD FALLING TOWARD 10F. 12Z INL RAOB
INDICATED A SHARP INVRN NEAR H9 ABV THIS FAIRLY SHALLOW INFUSION OF
COLD AIR...AND THERE IS QUITE A BIT OF LO CLD/SOME -SN IN THAT AREA
AS WELL. FARTHER UPSTREAM...BITTERLY COLD AIR IS PRESENT OVER THE W
HALF OF CANADA...WITH H85 TEMP AS LO AS -32C AT CALGARY. SOME OF
THIS COLD AIR IS SPILLING INTO THE NRN PLAINS...WHERE SFC TEMPS ARE
NOT MUCH ABV ZERO IN NDAKOTA. SEVERAL DISTURBANCES ARE NOTED WITHIN
THE WRN TROF...AND THERE IS A SOMEWHAT ILL DEFINED COMMA CLD NOTED
ON WV IMAGERY PUSHING INTO THE NRN PLAINS. BUT GENERAL DRYNESS IN
THAT AREA INDICATED BY H7 RAOBS HAS LIMITED THE PCPN COVERAGE.
&&
.SHORT TERM /TNGT AND TUE/... ISSUED AT 433 PM EST
MAIN FCST CONCERNS DURING THIS PERIOD REVOLVE ARND SN CHCS/AMOUNTS
AS COLDER AIR MOVES INTO THE UPR LKS AT SAME TIME DISTURBANCE IN THE
NRN ROCKIES MOVES BY JUST TO THE S.
TNGT...DISTURBANCE MARKED BY ILL DEFINED COMMA CLD IN THE NRN PLAINS
IS PROGGED TO MOVE INTO THE NCNTRL PLAINS BY 12Z TUE...WITH SFC LO
NOW TAKING SHAPE IN THE PLAINS DRIFTING NEAR LOWER MI. MEANWHILE...
COLDER AIR TO THE NW WL SLOWLY INFILTRATE THE UPR LKS AS THE LLVL
WIND TURNS MORE TO THE N...DROPPING H85 TEMPS TO ARND -15C OVER WRN
LK SUP TO -10C OVER THE E. WITH OPEN WATER TEMPS ARND 3C...THE
ARRIVAL OF THIS INCOMING AIRMASS WL BE SUFFICIENT TO GENERATE LES W
TO E. ALTHOUGH THE SHARPER FORCING ASSOCIATED WITH THE PLAINS SHRTWV
WL TEND TO BE FOCUSED JUST S OF UPR MI...THE 12Z NAM/GFS SHOW DEEPER
MSTR ARRIVING MAINLY OVER THE NW HALF OF THE CWA OVERNGT WHERE UPR
DVGC/H7-5 FGEN WL BE MAXIMIZED IN RRQ OF 120KT H3 JET MAX MOVING TO
NEAR JAMES BAY. FCST SDNGS SHOW THE ASSOCIATED OMEGA WL BE MAXIMIZED
FAIRLY HI CLOSER TO THESE HIER LVL FORCING MECHANISMS...SO POTENTIAL
FOR TRUE LK ENHANCEMENT IS PROBABLY MINIMAL. WITH GREATER OVERWATER
INSTABILITY AND SHARPER LLVL CNVGC OVER THE FAR W NEAR IWD PER NAM
FCST...EXPECT HEAVIER SHSN THERE IN THE PRESENCE OF FVRBL UPSLOPE N
WIND. ALTHOUGH THE LLVL FGEN WL BE SHARPER OVER THE SE ZNS CLOSER TO
THE SFC LO/FNT TO THE SE... THE AIRMASS APPEARS WL BE TOO DRY
OVERALL FOR ANY SGNFT PCPN THERE THRU 12Z.
TUE...UPR DISTURBANCE/SFC LO TO THE S WL SHIFT TO THE E...WITH
TRAILING SFC HI PRES FCST TO SHIFT TOWARD WRN MN BY LATE IN THE DAY.
DEEP MSTR ASSOCIATED MAINLY WITH HI LVL FORCING RELATED TO COUPLED
UPR DVGC IN RRQ OF UPR JET TO THE NE/LEFT EXIT OF JET SUPPORTING
SHRTWV IN THE LOWER LKS AND H7-5 FGEN WL EXIT W-E IN THE AFTN. BEST
CHC FOR WDSPRD PCPN WL BE INTO MID AFTN...WHEN MODELS SHOW SHARPER
UPR DVGC AND LINGERING FGEN TENDING TO EXIT TO THE E. ALTHOUGH PURE
LES WL LINGER EVEN AFT THE EXIT OF THE DYNAMICS AS H85 TEMPS TUMBLE
TOWARD -20C WITH INFLUX OF ARCTIC AIR TO THE NW...STEADILY BACKING
WINDS IN THE AFTN WL TEND TO LIMIT LES BAND RESIDENCE TIME AND
ACCUMS. AWAY FM LK MOISTENING...PLAN ON NO MORE THAN 1 TO 2 INCHES
OF SN WITH BETTER OMEGA ABV THE DGZ AND H85 CAD TENDING TO OFFSET
THE UPR DVGC/FGEN. EXPECT LTL DIURNAL RISE OF TEMP AS BITTERLY COLD
AIRMASS IN THE NRN PLAINS FOLLOWS INTO THE UPR LKS.
AS FOR HEADLINES...RETAINED GOING ADVY FOR GOGEBIC/ONTONAGON ZNS
WITH MOST FAVORABLE OVERWATER INSTABILITY/FETCH/UPSLOPE WIND
COMPONENT. OPTED TO ISSUE AN ADVY FOR BARAGA/MQT AS WELL FOR THE
09Z-21Z TIME WITH THE SAME FAVORABLE PARAMETERS. WITH WSHFT TO THE
NW ON TUE AFTN...THE HEAVIER SHSN SHOULD END IN THIS AREA EVEN
EARLIER THAN OVER THE W. COORDINATED WITH DLH ON HEADLINES FOR IWD
AREA.
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
TUESDAY NIGHT...
THE 500MB THROUGH CURRENTLY SET UP ACROSS MT THROUGH NV AND S CA
WILL BE DIRECTLY OVERHEAD AT 00Z WEDNESDAY...WITH THE MAIN LOW
SLOWLY SWINGING ACROSS CENTRAL TO NE CANADA. THE SFC LOW /FARTHER
EAST/ SHOULD BE JUST NORTH OF LAKE ONTARIO AT 00Z WEDNESDAY...WITH A
TROUGH EXTENDING THROUGH UPPER MICHIGAN INTO FAR WESTERN LAKE
SUPERIOR. N-NW WINDS WILL PREVAIL INITIALLY WITH 850MB TEMPS
AVERAGING -18C.
WEDNESDAY INTO THURSDAY...
BY 12Z WEDNESDAY THE TROUGH WILL RESIDE ACROSS EASTERN
UPPER MI...BEFORE BEING QUICKLY PUSHED EASTWARD BY MID MORNING
THANKS TO THE STRONG SFC RIDGE TO OUR SOUTH...AND ANOTHER LOW
NEARING FROM THE DAKOTAS. THE RESULT WILL BE WINDS BECOMING WESTERLY
AND SOUTHWESTERLY THROUGH THE DAY...WITH LES HOLDING ON THE LONGEST
ACROSS THE KEWEENAW PENINSULA AND FAR EAST NEAR LAKE SUPERIOR /INTO
THE MID MORNING HOURS/.
A WEAK RIDGE TO ZONAL FLOW CAN BE EXPECTED ALOFT WEDNESDAY...BEFORE
THE NEXT TROUGH SWINGS IN FROM MN WEDNESDAY NIGHT INTO THURSDAY
MORNING /ASSOCIATED WITH THE SFC LOW/. EXPECT THE SFC LOW TO PUSH
OVER THE WESTERN THIRD OF THE CWA BY 00Z...CENTRAL BY 06Z...AND
RESIDE JUST TO OUR EAST BY 12Z THURSDAY. THE 06Z RUN OF THE GFS IS
THE WEAKEST AND FARTHEST SOUTH WITH THIS FEATURE /APPROX 220 MILES
SSE OF THE ECMWF/. THIS MAKES TIMING THE ONSET OF PRECIPITATION
DIFFICULT...WITH THE ECMWF INDICATING A SHORT DRY PERIOD FOR MUCH OF
THE AREA WEDNESDAY AFTERNOON...WHILE THE KEWEENAW STAYS IN THE SNOW
IF THE GFS IS TO BE BELIEVED. AT THIS POINT...THE GFS LOOKS TO BE AN
OUTLIER...WITH LIMITED INPUT INTO THIS FORECAST FROM WEDNESDAY ON.
THE 12Z GFS HAS MOVED CLOSE TO THE CONSENSUS...SPLITTING THE
ORIGINAL 220 MILE DIFFERENCE IN HALF. ANY OF THE SOLUTIONS WOULD
BRING A CHANCE OF LES ON SOUTHERLY WINDS TO THE EASTERN CWA LATE
WEDNESDAY AFTERNOON INTO THE EVENING HOURS...BEFORE THEY BECOME TOO
MUCH OUT OF A SW OR W DIRECTION /850MB TEMPS OF -11 TO -14C SHOULD
BE COLD ENOUGH/.
THE MAIN 500MB LOW WILL REMAIN WELL TO OUR NORTH...SLOWLY
RETROGRADING WESTWARD FROM THE HUDSON BAY AREA TO AK BY THE END OF
THE WORK WEEK. A SIGNIFICANT TROUGH WILL STILL LINGER ACROSS N
HUDSON BAY FOR THE FORESEEABLE FUTURE.
THE COLDEST AIR SEEN IN SOME TIME WILL SLIDE IN THURSDAY...DROPPING
TO -24C BY THE AFTERNOON HOURS ON GUSTY NW WINDS...WITH LIKELY SNOW
SHOWERS RETURNING TO THE AREA NEAR LAKE SUPERIOR. THIS WILL BE THE
CASE UNTIL WAA SW WINDS TAKE HOLD AGAIN FRIDAY MORNING. WILL KEEP
THIS SYSTEM MENTIONED IN THE HWO...AND CONTINUE TO MONITOR IT
CLOSELY FOR THE POTENTIAL FOR HEADLINES AS IT MOVES CLOSER.
FRIDAY THROUGH MONDAY...
FCST MODELS BEGIN TO DIVERGE IN THE OVERALL PATTERN LATE
FRIDAY...WITH THE ECMWF AND CANADIAN KEEPING A TROUGH OVERHEAD WITH
THE GFS INDICATES MORE IN THE WAY OF SW FLOW. THESE DIFFERENCES
CONTINUE AND BECOME MORE DRAMATIC TROUGH MONDAY. THIS IS SEEN ON THE
SFC CHARTS AS WELL AT 00Z SUNDAY WITH THE LOCATION OF THE NEXT LOW
VARYING SOME 1K MILES BASED ON THE 16/06Z GFS AND 16/00Z ECMWF. THE
GFS HAS IT JUST NW OF LAKE SUPERIOR...WHILE THE ECMWF IS STILL
ORGANIZING THE FEATURE OVER SOUTHERN ALBERTA. GIVEN ALL THE
DIFFERENCES...WILL NOT DEVIATE MUCH FROM AN AVERAGE/BLENDED SOLUTION.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/...
MVFR CONDITIONS WILL PREVAIL THRU THE EVENING AT KIWD/KCMX/KSAW AS
GRADUALLY COOLING AIRMASS AND FLOW OFF LAKE SUPERIOR HELP TO
MAINTAIN LOWER CLOUDS. AS AIRMASS CONTINUES TO COOL FROM W TO E...
SNOW SHOWERS WILL DEVELOP OFF THE LAKE DURING THE NIGHT...
ESPECIALLY WHEN DEEPER MOISTURE ASSOCIATED WITH INCOMING UPPER LEVEL
DISTURBANCE ARRIVES. CONDITIONS SHOULD DETERIORATE TO IFR LATE IN
THE NIGHT THRU TUE MORNING...WITH THE BEST CHC FOR LIFR AT KIWD
WHERE OVERWATER INSTABILITY WILL BE MAXIMIZED IN THE PRESENCE OF
FAVORABLE/CONVERGENT UPSLOPE N WIND. IMPROVEMENT SHOULD OCCUR AT ALL
TERMINALS MID TO LATE AFTN AS DEEPER MOISTURE DEPARTS AND LOW-LEVEL
CONVERGENCE BEGINS TO WEAKEN.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT N WINDS UP TO 30 KTS/SOME FREEZING SPRAY ON TUE WITH INFLUX
OF COLDER AIR IN THE WAKE OF LO PRES SHIFTING E THRU THE LOWER LKS.
WINDS WL DIMINISH AND BACK TO THE SW TUE NGT THRU WED WITH THE
PASSAGE OF A RIDGE AXIS AND AHEAD OF ANOTHER LO PRES SYSTEM. A
BITTERLY COLD AIRMASS WILL FOLLOW THIS LO AS NW WINDS INCREASE TO
AOA GALE INTENSITY /MAINLY THURSDAY/. HEAVY FREEZING SPRAY WILL BE A
GOOD BET OVER MOST OF THE LAKE /MAINLY WEDNESDAY NIGHT INTO THURSDAY
WEST/ BEFORE WINDS DIMINISH AGAIN BY LATE IN THE WEEK WITH THE
APPROACH OF ANOTHER HI PRES RDG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 5 PM EST TUESDAY FOR
MIZ004-005.
LAKE EFFECT SNOW ADVISORY FROM 1 AM EST /MIDNIGHT CST/ TO
7 PM EST /6 PM CST/ TUESDAY FOR MIZ002-009.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
415 PM EST SUN JAN 15 2012
.SHORT TERM /TONIGHT THROUGH MONDAY/...
LES CONTINUES OVER THE FAR EASTERN CWA...WITH VIS FALLING TO A MILE
AT TIMES AROUND 18Z THIS AFTERNOON AT ERY. THE LATEST SATELLITE
IMAGERY INDICATE THIS BAND SLOWLY SHIFTING WESTWARD INTO SCHOOLCRAFT
COUNTY. WHILE A QUICK HALF AN INCH OR SO AN HOUR COULD STILL BE
POSSIBLE IN THE STRONGEST PORTIONS OF THE BAND...THE MOBILE NATURE
SHOULD KEEP ACCUMULATIONS IN CHECK THIS AFTERNOON INTO THE EVENING
HOURS.
THE STRONG S-SW WINDS WILL BRING AN INFLUX OF WARM AIR TO THE REGION
OVERNIGHT. EXPECT 850MB TEMPS TO RISE INTO THE SINGLE DIGITS BELOW
ZERO...TOPPING OUT FROM THIS AFTERNOON MUCH OF THE PERIOD. EXTENT OF
THE WARM AIR SLIDING FROM EASTERN MN ACROSS N WI IS OF A
CONCERN...AS THE 15/15Z RUN OF THE RUC13 SHOWS TEMPS AROUND 0C NEAR
ID AS EARLY AS 03Z MONDAY /3 TO 5C WARMER THAN THE CONSENSUS/.
OTHERWISE...MOST OF THE WARM AIR SHOULD BE CONCENTRATED OVER THE
CENTRAL PORTIONS OF THE CWA...TOPPING OUT 15Z MONDAY AROUND 0C FROM
CENTRAL WI THROUGH DELTA AND SOUTHERN MARQUETTE COUNTIES. WHILE ONE
FCST MODEL DOES SPIT OUT LITE PRECIP OVER THIS AREA AS EARLY AS
EARLY AFTERNOON TODAY...THE REMAINDER OF THE MODELS HOLD OFF UNTIL
AFTER 03Z MONDAY. WILL FOLLOW THE LATER AND ONLY INCLUDE FLURRIES
FOR THE REMAINDER OF TODAY...AS A SFC COLD FRONT/TROUGH NEARS FROM
CENTRAL MN. IF ANYTHING DOES FALL IT WOULD LIKELY BE IN THE FORM OF
FZDZ OVERNIGHT...WITH THE BEST SNOW GROWTH LAYER AROUND 700MB AT
IMT...AND ALL THE MOISTURE STUCK BELOW THE INVERSION HOVERING AROUND
900MB. WILL KEEP THE MENTION OF FZDZ IN THE FCST AND THE HWO. LOW
CLOUDS REMAIN POSSIBLE...ESPECIALLY WITH THE WAA...AS MOISTURE
ESCAPES THE AVG 2-4 INCHES OF SNOW OVER N WI. DEW POINTS LOOK
MINIMAL FOR SIGNIFICANT MELTING THOUGH...EXPECTED TO REMAIN IN THE
LOW 20F RANGE AT BEST. THE BEST MOISTURE PLUME WILL LIKELY REMAIN
OFF LAKE MICHIGAN...SLIDING NE INTO MARQUETTE COUNTY BY LATE EVENING
BEFORE A MORE SW WIND TAKES HOLD.
AS FOR MONDAY...MUCH OF THE MOISTURE WILL SLIDE OUT OF THE CWA AS
WINDS TURN W AND NW THROUGH THE DAYTIME HOURS AS THE COLD FRONT
SHIFTS ACROSS. EXPECT THE SFC LOW TO BE OVER CENTRAL ONTARIO BY 12Z
MONDAY...WITH THE COLD FRONT DRAPED ACROSS W LAKE SUPERIOR AND IWD.
BY 18Z IT WILL LIKELY STRETCH ACROSS ALGER AND MENOMINEE
COUNTIES...BEFORE EXITING EAST BY 00Z. THE MAIN STORY WILL BE THE
WIND SHIFT AND CLOUD COVER...WITH MUCH OF THE COLD AIR WAITING FOR A
UNTIL THE WINDS BECOME MORE NORTHERLY DURING THE LATE AFTERNOON
HOURS. IT STILL SHOULD BE ENOUGH TO BRING LES TO THE FAR W...WITH
LIGHT AMOUNTS EXPECTED.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
MONDAY NIGHT INTO TUESDAY NIGHT...THE SURFACE LOW MOVES FROM THE MID
MS VALLEY TOWARD THE SRN GREAT LAKES AS THE MID LEVEL TROUGH SWEEPS
THROUGH THE REGION. MODEL PREFERENCE REMAINS WITH THE MORE CONSISTENT
12Z/00Z ECMWF SUPPORTED BY THE UKMET WHICH BRING THE SFC LOW NEAR
CHICAGO BY 12Z/TUE AND TO DTW BY 18Z/TUE. THE GEM REMAINED STRONGER
AND FARTHER NORTH WHILE THE GFS WAS FARTHER SOUTH. MODERATE 700-300
QVECTOR CONV ASSOCIATED WITH THE MID LEVEL TROUGH AND UPPER LEVEL DIV
WITH THE RIGHT ENTRANCE OF THE UPPER LEVEL JET OVER ONTARIO WILL
SUPPORT AN EXPANDING AREA OF LIGHT SNOW ACROSS WI INTO UPPER MI LATE
MON NIGHT INTO TUE MORNING. INCREASING NRLY WINDS WITH 850 MB TEMPS
DROPPING TO -15C BY 12Z/TUE AND TO NEAR -18C BY 18Z/TUE WILL LEAD TO
LAKE ENHANCED SNOW FOR NORTH WIND SNOWBELTS. NAM COBB SNOW/WATER
RATIO OUTPUT SUGGESTS THAT THE HIGHER SNOW/WATER RATIOS ARE MORE
LIKELY OVER THE WEST...WHERE THE COLD AIR ARRIVES EARLIER. SNOWFALL
TOTAL GENERALLY IN THE ADVY CATEGORY ARE EXPECTED WITH 18 HOUR
AMOUNTS IN THE 4 TO 7 INCH RANGE. SNOW AMOUNTS OF AN INCH OR TWO AT
MOST ARE EXPECTED AWAY FROM LAKE SUPERIOR.
THE SNOWFALL IS EXPECTED TO DIMINISH FROM WEST TO EAST TUESDAY
AFTERNOON AS THE DEEPER MOISTURE DEPARTS AND SUBSIDENCE ACYC FLOW
BUILD INTO THE AREA. WINDS GRADUALLY BACK MORE TO THE WNW ON TUES
NIGHT AS SFC RIDGE APPROACHES THE AREA. LES INTENSITY WILL CONTINUE
TO DIMINISH BUT WITH AMPLE INSTABILITY (850 MB TEMPS STILL AROUND
-19C). SO WITH SNOWBAND POSITIONS SHIFTING OVERNIGHT...ADDITIONAL
ACCUMULATIONS WILL BE LIGHTER...GENERALLY IN THE 1 TO 3 INCH RANGE.
WEDNESDAY INTO THU...THE GFS WAS FASTER AND FARTHER SOUTH WITH THE
NEXT SHORTWAVE TROUGH IN QUICK WNW FLOW PATTERN. GIVEN LIMITED
CONFIDENCE WITH FCST DETAILS...ONLY CHANCE POPS FOR SYNOPTIC SCALE
SNOW WERE INCLUDED. NW FLOW LES WILL AGAIN DEVELOP IN THE WAKE OF
THE LOW FROM LATE WED NIGHT INTO THU AS 850 MB TEMPS FALL INTO THE
-20C TO -25C RANGE.
THU NIGHT INTO FRI...AFTER A TRANSIENT RIDGE MOVES THROUGH THU
NIGHT...MODELS SUGGEST THAT A WAA PATTERN AHEAD OF THE NEXT
SHORTWAVE AND SFC TROUGH COULD BRING LIGHT SNOW TO THE AREA FRI.
SAT INTO SUN...ECMWF/GFS AND ASSOCIATED ENSEMBLES SHOW TRANSITION
TOWARD A MILDER PATTERN WITH A RETURN TO MUCH ABOVE NORMAL
TEMPERATURES BY SUN AND INTO NEXT WEEK. THERE MAY BE SOME LIGHT PCPN AS
A WARM FRONT MOVES INTO THE AREA...BUT ANY PCPN WOULD LIKELY BE
LIGHT.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
THE CLEARING LINE OF LOW END MVFR CEILINGS IS SET UP ACROSS NORTHERN
WI AND SLIDING INTO IWD...MOVING NE AROUND 20KTS. AT THIS POINT THAT
WOULD RESULT IN THE CLEARING LINE OVER CMX AND SAW AROUND 20-21Z.
THIS WILL BE AROUND THE SAME TIME WHEN STRONGER WINDS BEGIN TO SLIDE
IN ALOFT...AROUND 2-4KFT MAXING OUT AROUND 45-55KTS BETWEEN 01-05Z
MONDAY. ALONG WITH STRONG WINDS /GUSTING INTO THE 22-30KT RANGE AT
THE SFC/ THERE WILL ALSO BE A VERY SMALL CHANCE OF FREEZING DRIZZLE
AS ANOTHER ROUND OF CLOUDS SLIDE IN AFTER 00Z. WILL KEEP IT OUT OF
THE FCST AT THIS TIME DUE TO THE LIMITED POTENTIAL /WITH THE BEST
CHANCE BEING WELL INLAND OF W LAKE SUPERIOR/. WILL STILL PLAY UP
ADDITIONAL LOW LEVEL MOISTURE AT ALL LOCATIONS...WITH SNOW SHOWERS
AROUND DAY BREAK AS FAVORABLE W WINDS BECOME MORE NW AT CMX AND IWD.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
BETWEEN THE EXITING HIGH TO OUR SE...AND NEARING LOW TO THE
WEST...STRENGTHENING SW FLOW WITH GALES OF 35 TO 40KTS WILL BE
POSSIBLE LATE THIS AFTERNOON THROUGH THE OVERNIGHT HOURS /STRONGEST
OVER THE EASTERN HALF OF LS/. LOW PRESSURE ACROSS SOUTHEASTERN
MANITOBA WILL SHIFT TO CENTRAL ONTARIO BY DAYBREAK MONDAY...AND EXIT
TO WESTERN QUEBEC WHILE DRAGGING A TROUGH ACROSS LS DURING
THE DAY MONDAY. AN ADDITIONAL LOW WILL RIDE ALONG THE TROUGH...FROM
THE MID MISSISSIPPI VALLEY TO THE LOWER GREAT LAKES MONDAY NIGHT
INTO TUESDAY MORNING...BEFORE EJECTING TO THE NEW ENGLAND STATES
TUESDAY EVENING. EXPECT A 30.2 INCH RIDGE TO BUILD ACROSS LS TUESDAY
NIGHT INTO WEDNESDAY. LOW PRESSURE OVER THE DAKOTAS WEDNESDAY
MORNING WILL DEEPEN ACROSS THE UPPER GREAT LAKES WEDNESDAY NIGHT.
THE LOW WILL THE SHIFT TO WESTERN QUEBEC THURSDAY EVENING...WHILE
HIGH PRESSURE SINKS ACROSS THE UPPER GREAT LAKES. THE HIGH PRESSURE
SYSTEM WILL THEN FILL FRIDAY AFTERNOON OVER THE LOWER GREAT
LAKES...WHILE ANOTHER LOW NEARS FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 AM EST MONDAY FOR LSZ266-267.
GALE WARNING UNTIL 1 AM EST MONDAY FOR LSZ244-245-265.
GALE WARNING UNTIL 7 AM EST MONDAY FOR LSZ263-264.
LAKE MICHIGAN...
GALE WARNING UNTIL 7 AM EST MONDAY FOR LMZ248-250.
&&
$$
SHORT TERM...KF
LONG TERM...JLB
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
606 PM CST MON JAN 16 2012
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
COLD FRONT WHICH PASSED ACROSS AREA LAST NIGHT NOW ACRS E IA INTO
SE WI WITH NW WINDS IN WAKE OF FRONT PRETTY MUCH KEEPING AFTERNOON
TEMPS STEADY ACROSS OUR AREA. UPPER TROF NOW MOVING ACROSS CNTRL
MT/W WY AND SHUD NEAR THE DKTS BORDER BY 12Z. -SN HAS BEEN
EXPANDING DURING THE AFTERNOON BACK ACROSS SODAK WITH MOST
STATIONS WEST OF HON REPORTING -SN AND PIR DOWN TO 3/4SM.
PROGRESSION OF UPPER TROF WILL CONTINUE TO PUSH PCPN EASTWARD
ACROSS OUR AREA OVERNIGHT. NOT A LOT TO WORK WITH FOR MUCH QPF
WITH CAA AT 850 MB AND ONLY NEUTRAL TO VERY WEAK WAA UP AT 700MB.
MODELS HAVE ALL BEEN PRETTY CONSISTENT FOR SEVERAL RUNS NOW
SPITTING OUT ANYWHERE FROM .05 TO .10 QPF. PCPN SHUD REACH W MN
BORDER AROUND 00Z AND EXPAND TO MSP AROUND 06Z. EXPECT A BROAD
AREA OF AROUND AN INCH OF SNOW ACROSS MOST AREAS...MAYBE A FEW
HIGHER AMOUNTS ACROSS S 1/2 OF AREA OVERNIGHT AND TUES MRNG. ONE
THING THIS SYSTEM DOES HAVE GOING FOR IT IS THAT THE ATMOSPHERE IS
COLD SO MORE EASILY SATURATED AND SNOW RATIOS WILL BE IN THE 20:1
RANGE.
E-W THERMAL RIBBON GETS A BRIEF SHUNT SOUTH IN THE WAKE OF THIS
SYSTEM AS HIGH PRESSURE BUILDS ACROSS AREA TUESDAY/TUESDAY EVENING.
TUESDAY NIGHT MAY SEE MIN TEMPS BFR MIDNIGHT IN W AREAS AS WINDS
BEGIN TO BECOME SOUTHERLY AHEAD OF NEXT FAST MOVING LOW PRESSURE
PUSH ACROSS NODAK BY 12Z WEDNESDAY. MODELS ARE A BIT CLOSER NOW ON
PATH OF THIS WAVE ACROSS CENTRAL MN ON WEDNESDAY KEEPING BETTER
POPS TO OUR NORTH. MORE FORMIDABLE ARCTIC PLUNGE IN THE WAKE OF
THIS WAVE WITH -25C 850 MB TEMPS INTO CENTRAL MN BY 06Z THURSDAY
SETTING US UP FOR A COLD THURSDAY MORNING AS SURFACE HIGH PRESSURE
ARRIVES IN SW MN OVER WHAT SHOULD BE AN INCH OF SNOW COVER.
INTERESTING FOR LATE THURSDAY/FRIDAY WITH SNOW POTENTIAL.
GFS/EC/GEM ALL BRING A FAST MOVING TROF THRU AREA. DIFFERENCES ON
TIMING AND QPF PLACEMENT...BUT ALL TRY AND CAPTURE THIS WAVE.
GFS/GEM CURRENTLY A BIT FASTER WITH QPF PLACEMENT MORE ACROSS SW
MN THURSDAY NIGHT AND FRI MRNG...WITH ECMWF MORE OF A FRIDAY EVENT
ACROSS A LARGER PORTION OF AREA. WITH STRONG BAROCLINIC ZONE TO
FEED ON...THERE SEEMS TO BE AT LEAST SOME POTENTIAL OF
ACCUMULATING SNOW.
OUT INTO NEXT WEEK...LOTS OF DIFFERENCES BETWEEN GFS/EC WITH GFS
DEVELOPING LW TROF ACROSS CENTRAL U.S. EARLY IN THE WEEK AND EC
DIGGING THE ENERGY MUCH FARTHER SOUTH KEEPING OUR AREA MUCH WARMER
AND DRIER. NOT A LOT OF CONFIDENCE IN GOING EITHER WAY...BUT TREND
FOR THE WINTER UP TO THIS POINT HAS BEEN MORE TOWARD THE EC SOLUTION.
&&
.AVIATION.../00Z TAF ISSUANCE/
WEATHER UNFOLDING PRETTY AS EXPECTED THIS EVENING...SO MADE VERY
MINOR TWEAKS TO THE GOING TAFS. SREF PROB FOR VIS LESS THAN 3SM
CAPTURING SNOW LOCATION WELL AT 00Z...SO USED IT TO TIME SNOWFALL
ACROSS THE TERMINALS. BASICALLY SLOWED ONSET OF SN BY AN
HOUR...BUT A FURTHER SLOWING BY AN HOUR OR TWO MAY BE NEEDED BASED
ON HRRR REFLECTIVITY FORECASTS. BASED ON OBS ACROSS
SODAK...CONDITIONS SHOULD REMAIN MAINLY VFR UNTIL SNOW
STARTS...WITH MVFR VIS SNOWS GIVING WAY TO IFR VIS SNOWS WITHIN AN
HOUR. EXPECT HEAVIEST SNOW TO PASS ACROSS ALL BUT AXN/STC AND HAVE
TEMPO 3/4SM VIS GROUPS TO ACCOUNT FOR THIS. ALL MODELS CONSISTENT
WITH PUTTING DOWN A 1-2 INCH SWATH OF SNOW ACROSS THE ENTIRE AREA
AND GIVEN GENERALLY GOOD MODEL AGREEMENT...THIS IS A RATHER HIGH
CONFIDENCE FORECAST. BEHIND THE SNOW...CONDITIONS LOOK TO IMPROVE
RAPIDLY...WITH NOTHING MUCH MORE THAN HIGH CLOUDS EXPECTED BY THE
AFTERNOON AT MN TAF SITES. WINDS SHOULD REMAIN STRONG AND OUT OF
THE NORTH INTO TUESDAY AFTERNOON...WHEN A WEAKENING AND BACKING OF
THE WINDS TOWARD THE WEST IS EXPECTED AS SFC RIDGE MOVES INTO WRN
MN.
KMSP...MODEL AGREEMENT STRONG FOR UPCOMING SNOW EVENT. SREF PLUMES
SHOW A STRONG CLUSTERING FOR SNOW START BETWEEN 5Z AND 8Z. GIVEN
DRY AIR TO OVERCOME...FAVORED THE SLOWER SIDE OF THE ENVELOPE FOR
START TIME. HEAVIEST SNOW SHOULD OCCUR RIGHT AT THE START OF THE
MORNING PUSH...SO COULD BE A BIT OF A SLOW START TO THE DAY. A
LITTLE LESS CONFIDENCE ON THE END TIME FOR THE SNOW...BUT SREF
MEMBERS PUT IT ANYWHERE BETWEEN 14Z AND 18Z. ONCE THE SNOW IS
DONE...NO FURTHER ISSUES WEATHER WISE ARE EXPECTED THIS TAF PERIOD.
//OUTLOOK FOR 12Z WED THROUGH 00Z SAT...
WED...SLGT CHC FOR AFTERNOON SN. MVFR POSSIBLE IF IT OCCURS.
THU...VFR.
THU NGT-FRI...IFR POSSIBLE WITH CHC OF SN.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
920 PM CST MON JAN 16 2012
.UPDATE...
/920 PM CST MON JAN 16 2012/
HAVE MADE UPDATES TO GO WITH LIKELY POPS THE REST OF THE EVENING
WHERE SHOWERS AND THUNDERSTORMS HAD DEVELOPED OVER MID MISSOURI.
THE HRRR HAS DONE A DECENT JOB THIS EVENING DEPICTING THIS
DEVELOPMENT...AND SHOWS IT MOVING EAST NORTHEASTWARD TOWARD THE MS
RIVER. SHOWERS AND THUNDERSTORMS HAVE ALSO DEVELOPED OVER SOUTHEASTERN
KANSAS AHEAD IN RESPONSE TO INCREASING ASCENT AHEAD OF A SHORTWAVE
CURRENTLY MOVING ACROSS THE CENTRAL PLAINS. EXPECT THIS AREA TO
SPREAD EAST INTO CENTRAL AND SOUTHEAST MISSOURI BY 06Z...SO LIKELY
AND CATEGORICAL POPS OVER THE SOUTHEAST TWO THIRDS OF THE CWA
OVERNIGHT STILL LOOKS GOOD. RUC STILL DEPICTS THAT BEST VERTICAL
MOTION WILL BE EXITING THE AREA JUST AHEAD OF WHEN LOW LEVEL
THERMAL PROFILES WILL SWITCH OVER TO SNOW OR SLEET. GOING FORECAST
FOR A BRIEF SWITCH OVER TO SNOW WITH LITTLE ACCUMULATION OVER
NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS STILL LOOKS
GOOD...WITH FLURRIES LINGERING INTO TUESDAY MORNING.
BRITT
&&
.DISCUSSION...
/313 PM CST MON JAN 16 2012/
IT WAS THE CLOUDS. SC CLOUD FIELD WAS ABOUT 4-6 HOURS DELAYED IN
GETTING IN HERE AND NEVER DEVELOPED THAT WELL SINCE IT OCCURRED
DURING THE DAY...AND WITH FULL SUNSHINE FOR A GOOD PART OF THE DAY
AND A STOUT SW WIND GUSTING TO 40MPH AT TIMES...TEMPS SURGED TO NEAR
RECORD LEVELS THIS AFTERNOON IN SOMETHING THAT WAS MORE REMINISCENT
OF MID APRIL THAN MID JANUARY. IN FACT...A RECORD MAX TEMP WAS
BROKEN AT KCOU OF 70 DEGREES...WITH THE RECORD TEMP OF 71 AT KSTL
BEING THREATENED. WEAK LO PRES EXISTED OVER N CNTRL MO AT 20Z WITH
A CDFNT EXTENDING TO THE NE AND SW OF THIS LO PRES THRU ERN IA AND
ERN KS. A WRMFNT HAS PUSHED INTO THE FAR NERN FA IN CNTRL IL.
APPROACH OF LEAD MID LEVEL SHORTWAVE THIS EVENING AND SFC CDFNT
IMMERSING ITSELF IN AN EVER INCREASINGLY MOIST ATMOSPHERE SHOULD
FINALLY LEAD TO BREAKOUT OF PCPN...ESPECIALLY LATE THIS EVENING...
WITH IT REACHING ITS PEAK OVERNIGHT...WITH HI PROBABILITIES COVERING
AREAS ALONG-SE FROM CNTRL MO TO CNTRL IL. ENOUGH ELEVATED
INSTABILITY WILL MOVE IN WITH THIS PCPN TO WARRANT CONTINUED MENTION
OF DECENT PROBS FOR TSRA...WITH CAPES OF 200-300 J/KG...MAINLY FOR
AREAS ALONG-S OF I-70. COULD STILL SEE BRIEFLY A POTPOURRI OF PCPN
TYPES LATE TONIGHT FOR PARTS OF NE-CNTRL MO AND W CNTRL IL BEFORE
FIRST DRY PUNCH COMES IN...BUT EXPECTED BREVITY AND INTENSITY OF
PCPN SHOULD BE SUCH WHERE LITTLE OR NO ACCUM WILL BE SEEN. AHEAD OF
THE FRONT...TEMPS SHOULD REMAIN QUITE MILD...WITH READINGS OF 50+
BUT LOOK FOR A RAPID TEMP DROP OFF INTO THE 30S BEHIND THE FRONT...
EVENTUALLY INTO THE MID-UPR 20S FOR PARTS OF NE-CNTRL MO AND W CNTRL
IL. SO NOT QUITE THE SAME PUNCH AS THE LAST FRONT AND SNOW EVENT
WITH OUR DROP INTO THE UPPER TEENS. FAVORED THE WARMER MOS FOR MIN
TEMPS TONIGHT FOR AREAS N AND W OF STL METRO WHILE OUTRIGHT GOING
ABOVE IT FOR AREAS WHERE THE FRONT WILL MAKE A VERY LATE PASSAGE.
RAIN SHOULD LINGER OVER AREAS S AND E OF STL METRO PAST 12Z WHERE
FROPA IS NOT EXPECTED TO OCCUR YET...WITH JUST DRIZZLE OR FLURRIES
LEFTOVER ELSEWHERE DURING THE MORNING UNTIL SECOND AND FINAL DRY
PUNCH PUSHES THRU WITH TRANSITION TO ANTICYCLONIC SFC FLOW. MOS
TEMP TRENDS FROM TONIGHT SHOULD CONTINUE WITH MOS BLEND FAVORED FOR
AREAS N AND W OF STL METRO WHILE ABOVE THE HIGHEST MOS FOR AREAS S
AND E OF STL METRO DUE TO THE DIFFERENT WAYS MOS MAX/MIN TEMPS ARE
CALCULATED VERSUS THE FCST. DECENT BUST POTENTIAL ON TEMPS TONIGHT
AND TOMORROW DUE TO THE TIMING OF THE FRONT AND SHARP GRADIENT IT
WILL CARRY WITH IT...AN HOUR OR TWO OFF ON TIMING WILL MAKE A BIG
DIFFERENCE.
MODELS ARE A TAD FASTER ON TRANSLATIONAL SPEED OF HI PRES AXIS
TUESDAY NIGHT...AND HAVE TWEAKED MIN TEMPS UP FOR KUIN-KCOU AREAS
BUT CONTINUED AOB LOWEST MOS ELSEWHERE.
GFS HAS COME IN CONSIDERABLY COLDER WITH WEDNESDAY NIGHT/EARLY
THURSDAY CDFNT WHILE THE NAM AND ECMWF NOT SO MUCH. FOR NOW WENT
WITH A BLEND AS MOST MODELS WANT TO GIVE US A GLANCING BLOW WITH
THIS AIRMASS AND NOT A DIRECT HIT.
MEDIUM RANGE FOR THE WEEKEND AND EARLY NEXT WEEK STILL LOOKS IFFY ON
THE DETAILS BUT BROAD PICTURE STILL LOOKS CONSISTENT...SHOWING A
PROGRESSIVE FLOW TRANSITIONING TO AN APPROACHING TROF FROM THE W.
THIS SHOULD INDICATE OVERALL MILD TEMPS WITH SPOTTY PCPN CHCS. THE
FRIDAY EVENT STILL LOOKS THE SAME WITH LO PROBS FOR LIGHT MIXED PCPN
WITH BETTER CHCS AHEAD OF THE DEEP TROF ON MONDAY.
TES
&&
.AVIATION...
/541 PM CST MON JAN 16 2012/
SFC LOW NEAR UIN WITH CDFNT EXTENDING SW OF LOW THROUGH W CNTRL MO...
JUST S OF MCI. THIS SFC LOW WILL DEEPEN AS IT MOVES NEWD DRAGGING
THE CDFNT SEWD THROUGH OUR AREA TGT. THE SFC WIND WILL VEER
AROUND TO A W-NWLY DIRECTION AFTER FROPA THIS EVNG IN UIN...AROUND
06Z TUE AT COU AND LATE TGT IN STL/SUS. LOW LEVEL MVFR CLOUDS
SHOULD DEVELOP ACROSS THE AREA THIS EVNG ALONG AND AHEAD OF THE
CDFNT AS THE ATMOSPHERE CONTINUES TO MOISTEN WITH AT LEAST SCATTERED
SHOWERS AND A FEW STORMS BREAKING OUT. THE CEILING WILL CONTINUE
TO LOWER AFTER FROPA DOWN TO AROUND 1000 FT. MAY HAVE A BRIEF
PERIOD OF SNOW IN UIN BEFORE THE PRECIPITATION SHUTS OFF LATE
TGT/EARLY TUE MRNG...OTHERWISE LITTLE IF ANY WINTRY PRECIPITATION
IS EXPECTED AT THE OTHER TAF SITES. THE CLOUD CEILING WILL
GRADUALY RISE DURING THE DAY ON TUE AS A STRONG SFC RIDGE BUILDS
SEWD INTO MO. NWLY SFC WINDS WILL BE QUITE STRONG AND GUSTY ON TUE
DUE TO THE TIGHT SFC PRESSURE GRADIENT BETWEEN THIS SFC RIDGE AND
THE DEEPENING SFC LOW MOVING NEWD THROUGH THE GREAT LAKES REGION.
SPECIFICS FOR KSTL...SWLY SFC WINDS WILL VEER AROUND TO A W-NWLY
DIRECTION BY 09-10Z TUE AFTER FROPA. MVFR CIGS ALONG WITH SHOWERS
AND A FEW STORMS SHOULD DEVELOP LATE THIS EVNG AND CONTINUE
OVERNIGHT. THE CEILING WILL FALL TO AROUND 1000 FT AFTER FROPA.
STRONG AND GUSTY NWLY SFC WINDS CAN BE EXPECTED ON TUE DIMINISHING
TUE EVNG AS THE SFC RIDGE AXIS APPROACHES. THE CEILING HEIGHT WILL
GRADUALLY RISE DURING THE DAY ON TUE EVENTUALLY SCATTERING OUT BY
EARLY TUE EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
525 PM CST Mon Jan 16 2012
...UPDATED AVIATION...
.DISCUSSION...
Dry air and good mixing prevented many low clouds from developing
today which allowed temperatures to soar well into the 60s across the
southeast 3/4 of the forecast area. Meanwhile a cold front continues
to organize and slowly push south into far northern Missouri late
this afternoon. This front will accelerate southward this evening as
a weak shortwave tracks into the Central Plains. As this feature
interacts with the front and low level wind fields increase, a band
of frontogenesis will develop in the 900-800 hPa layer across the
southern half of the area late this evening. This should allow
scattered light precipitation to develop across eastern Kansas into
central Missouri after sunset, which will likely grow in intensity
and coverage across far southern portions of the area after 06Z as
frontogenesis intensifies. An elevated theta-e maximum near 850-hPa
may allow for some elevated thunder as well, especially across the
southern third of the forecast area.
Meanwhile further north, an additional band of postfrontal light
snow will expand out of the Dakotas into Nebraska and Iowa overnight
ahead of the upper wave. Expect the bulk of this activity to remain
north of the forecast area in a region of better upper level support,
though some light accumulating snow (or sleet) may be possible as far
south as Highway 36 where weak deformation and convergence will set
up along the lagging 850 hPa front. Interestingly, the 18Z run of the
NAM is producing between 0.2 and 0.3 inches of QPF across the
northern forecast area overnight. This seems to be an anomalous run
as its forecast deep moisture profile is much more moist than
previous runs, which doesn`t seem supported by looking upstream.
Between this and the shower and thunderstorm activity further south,
there may be a relative minimum in precipitation across the KC-Macon
corridor for much of the night. However, still can`t rule out some
light precip across these areas toward midnight given the broad
ascent ahead of the upper wave. Thermal profiles suggest that any
precipitation that does develop overnight would initially be rain
south of Highway 36, before transitioning to a light wintry mix
across the KC- Macon corridor around 08Z and across central Missouri
by 11Z. At this time precipitation amounts look to be much too light
by the time this transition occurs to produce any measurable snow or
ice accumulation.
This system will shift into the Great Lakes on Tuesday with deep cold
air advection spreading into the region. Skies should gradually clear
from west to east through the day, though concerned that models may
be moving the clearing line too quickly across the forecast area as
they often do in similar CAA regimes. A large surface high will be
quick to build into the region by Tuesday afternoon, shifting into
the Mississippi Valley by 12Z Weds. This will allow temperatures to
fall into the teens, though didn`t go quite as cold as guidance
numbers given how quickly winds will increase from the south after
09Z. Warm air advection will send temperatures back above average by
Wednesday while skies remain mostly sunny.
Hawblitzel
Medium Range (Thursday - Sunday):
Models show reasonable agreement with the upper level pattern
through the extended with nearly zonal to northwesterly flow
prevailing. There is also decent agreement tracking a wave through
the flow Friday into Saturday. The ECMWF is a little more aggressive
with the mid level circulation associated with short wave and as a
result depicts a bit more QPF. Prefer the GFS which keeps the mid
level wave open and therefore not as aggressive with any possible
precipitation. Will keep only slight chances in for the northeastern
half of the forecast area for Friday as this systems tracks through
given the preference for a drier short wave passage. Beyond the
small chances for precipitation on Friday for a portion of the
forecast area the rest of the forecast looks to be above to well
above normal with highs returning to the 50s on Sunday. The next
shot of precipitation may come early next week with models showing a
deep trough coming out of the southwest. This seems to correspond to
the arctic oscillation heading to more of a neutral to slightly
negative outlook per the GFS ensemble data which would indicate
colder temperatures for the area. But this is well into the future
and beyond the scope/timeframe of this forecast so we`ll continue to
monitor trends and see how the pattern evolves over the next 7-8
days.
CDB
&&
.AVIATION...
Cold front had passed through terminals prior to this 00Z issuance
time with colder air/lower cigs lagging the wind shift. Elevated
convective elements have already been noted on regional radar across
SW KS/NW OK with propagation vectors bringing sct precipitation into
the terminal corridor around 05Z, while lower cigs advect south from
Nebraska with the colder air.
Preferred a blend in timing/precipitation duration of HRRR and high
resolution WRF members which have any precipitation only temporarily
affecting any one terminal site later this evening. Bufr soundings
indicate mostly rain initially, then changing to snow before quickly
ending. Have concerns given convective nature of some graupel/sleet
mix as well, but did not include in this package given lower
confidence though planners will need to consider this possibility.
Have trended into lower mvfr cigs late tonight, eventually rising
and scattering to vfr later Tuesday morning with moderate
confidence.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1156 AM CST SUN JAN 15 2012
.AVIATION...
VFR FLIGHT RULES TO PREVAIL THROUGH THIS EVENING...WITH WESTERLY
WIND SPEEDS BECOMING GUSTY AT TIMES THIS AFTERNOON. STRONG MIXING
SHOULD ALLOW THE TRANSFER OF MOMENTUM ALOFT TO THE SURFACE...WHICH
WOULD SUGGEST WIND GUSTS OF UP TO 20KTS ACROSS NORTHWEST NEBRASKA.
ELSEWHERE 15 KTS SEEMS REASONABLE. AN ARCTIC FRONT WILL CROSS THE
REGION LATER THIS EVENING...BRINGING A WIND SHIFT AND POSSIBLY -SN
MID DAY TOMORROW. HAVE THE FRONTAL PASSAGE NEAR THE VTN TERMINAL
AROUND 00Z MONDAY...AND THROUGH LBF BY 03Z. WIND GUSTS FROM THE
NORTH NORTHWEST OF UP TO 17KTS WILL OCCUR ALONG AND BEHIND THE
FRONTAL PASSAGE.
&&
.PREV DISCUSSION... /ISSUED 712 AM CST SUN JAN 15 2012/
UPDATE...
SHORT TERM...
A LOOK AT THE MORNING UA FLIGHTS FROM LBF...UNR AND DNR AS WELL AS
THE RUC...GEM REG AND HRRR FORECAST TEMPS SUGGESTED RAISING 1ST
PERIOD MAX TEMPS A FEW DEGREES. WITH DEEPER VERTICAL MIXING TO
850 MB THESE TEMPS SHOULD BE REACHABLE AND STRONGER WINDS NEAR THE
BREEZY CATEGORY SHOULD DEVELOP AS WINDS AT H850 ARE FCST TO REACH 30
TO 35 KTS.
THE HRRR SUGGESTED RED FLAG CONDITIONS BUT A BLEND OF HRRR AND
DRIER MAV GUIDANCE USING THE WARMER HIGHS ONLY PRODUCED RH NEAR 20
PERCENT SO THE UPDATED FCST DOES NOT INCLUDE A RED FLAG WARNING.
PREV DISCUSSION... /ISSUED 400 AM CST SUN JAN 15 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
FORECAST CONCERNS THROUGH THIS PERIOD DEAL WITH SNOW CHANCES
MONDAY AND MONDAY NIGHT AS WELL AS TEMPERATURES THROUGHOUT THE PERIOD.
AT 08Z WATER VAPOR IMAGERY SHOWED RIDGING OVER THE CENTRAL AND
NORTHERN PLAINS AS A SHORTWAVE TROUGH MOVED INTO THE PACIFIC
NORTHWEST WITH AN ENHANCED BIT OF ENERGY PLACED OVER SOUTHERN SASKATCHEWAN.
MEANWHILE ANOTHER CIRCULATION WAS OBSERVED OFF THE CALIFORNIA
COAST IN THE SOUTHERN STREAM. CLOSER TO HOME...THERE WERE A FEW
CLOUDS SEEN OVER THE FORECAST AREA EARLY THIS MORNING MOVING OVER
THE RIDGE...AND WITH WARM AIR PUSHING IN...TEMPERATURES STAYED
MILD FOR THIS TIME OF YEAR. AT 08Z...OBSERVATIONS INDICATED MID
20S TO LOW 30S ACROSS MUCH OF NEBRASKA. PLENTIFUL WARM AIR
ADVECTION HAS BEEN TAKING PLACE OVERNIGHT AS COMPARING LAPS
SOUNDINGS TO THE KLBF SOUNDING FROM 15.00Z WOULD SHOW AN INCREASE
IN TEMPERATURES BETWEEN 800 TO 850MB OF AROUND 9 DEGREES FROM 00Z
TO 07Z.
BUFKIT FORECAST SOUNDINGS FROM BOTH THE NAM/GFS ARE NOT HANDLING THE
WARM AIR PATTERN FOR TODAY WELL AS THEY FAILED TO MIX OUT THE
BOUNDARY LAYER THIS AFTERNOON. THIS HAS BEEN A PROBLEM IN THE PAST
WHICH HAS FORECASTED TEMPERATURES MUCH TOO COLD...SO DID NOT LOOK AT
THESE MODELS FOR TEMPERATURES TODAY. FROM THE FORECAST SOUNDINGS
ASSUMING MIXING TO 850 OR 875MB WOULD BRING TEMPERATURES THIS
AFTERNOON INTO THE 60S ACROSS MUCH OF SOUTHWEST INTO CENTRAL
NEBRASKA. THESE NUMBERS WILL BE WELL ABOVE NORMAL...BUT DON/T
EXPECT TO REACH RECORD NUMBERS TODAY. CONFIDENCE ROSE IN THAT LAST
STATEMENT AS STANDARDIZED ANOMALY DATA SHOWED 850MB TEMPERATURES
AT 1.5 STANDARD DEVIATIONS ABOVE NORMAL. WOULD LIKE THAT TO BE
HIGHER IF FORECASTING RECORD NUMBERS. WINDS AT THE TOP OF THE
MIXED LAYER WILL ONLY BE 15 TO 20KTS SO DON/T EXPECT WINDS TO BE
TOO STRONG TODAY. THIS IS A POSITIVE IN TERMS OF FIRE WEATHER
CONCERNS AS RELATIVE HUMIDITY WILL BE LOW TODAY. SEE FIRE WEATHER
DISCUSSION BELOW FOR MORE DETAILS.
AS TODAY PROGRESSES...THE SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST WILL MOVE EAST TOWARDS THE NORTHERN ROCKIES WITH THEA
SHORTWAVE TROUGH OVER SASKATCHEWAN WILL MOVE EAST ACROSS SOUTHERN
CANADA. THIS WILL LEAD TO A SURFACE FRONT CENTERED OVER SOUTHERN
CANADA TO ALSO MOVE EAST...DRAGGING ALONG A COLD FRONT ACROSS THE
PLAINS. THE TIMING OF THE FRONT WILL BE TO MOVE INTO NORTHWEST
NEBRASKA LATER THIS AFTERNOON...SO HIGH TEMPERATURES SHOULD SEE
LITTLE AFFECT FROM COLDER AIR COMING SOUTH.
TEMPERATURES TONIGHT WILL DROP SIGNIFICANTLY AS HIGH PRESSURE
BUILDS IN FROM THE NORTH TO WEAKEN THE WINDS AND PUSH ANY CLOUDS
OUT OF THE AREA /ESPECIALLY OVER THE PANHANDLE/. ONGOING FORECAST
IS A BIT WARMER THAN SOME STATISTICAL GUIDANCE...WITH THE
UNCERTAINTY IN THE DROP OFF OF WINDS TO IMPACT THE FORECAST LOWS.
THE MAIN PACIFIC NORTHWEST SHORTWAVE WILL PASS ACROSS THE ROCKY
MOUNTAINS BY MONDAY MORNING AND INTO THE NORTHERN AND CENTRAL
PLAINS THROUGH THE DAY MONDAY. THIS SYSTEM WILL BRING SNOW CHANCES
TO THE FORECAST AREA FOR MONDAY AND MONDAY NIGHT. DID BACK OFF A
BIT ON SNOW CHANCES MONDAY MORNING AS A SUBSTANTIAL DRY LAYER
LOOKS TO BE IN PLACE ACCORDING TO CROSS SECTIONS AND FORECAST
SOUNDINGS TO SLOW THE ONSET OF PRECIPITATION AS THE COLUMN
SATURATES. HIGHEST CHANCES ARE GOING TO COME AFTER 18Z MONDAY
THROUGH 17.06Z AS THE COLUMN IS SATURATED AND COMBINES WITH THE
STRONGEST UPPER LEVEL DYNAMICS AS WELL A FRONTOGENESIS SIGNAL IN
THE 700 TO 600MB LAYER. THE SYSTEM AS A WHOLE WILL HAVE QUITE A
BIT OF MOISTURE WITH IT...BUT A GREAT DEAL OF THAT MOISTURE WILL
BE SQUEEZED OUT AS IT OVERPASSES THE MOUNTAINS. THUS ONLY LOOKING
FOR LIGHT SNOW AMOUNTS FOR MONDAY AND MONDAY NIGHT. AS MUCH COOLER
AIR WILL BE IN PLACE ALOFT...HIGHS MONDAY WILL BE SOME 30 DEGREES
COOLER THAN WHAT OCCURRED SUNDAY. MONDAY NIGHT IS LOOKING TO BE
THE COLDEST NIGHT OF THE WEEK AS 850MB TEMPERATURES DROP TO 12 TO
15 DEGREES BELOW ZERO. THERE DOES REMAIN SOME UNCERTAINTY TO HOW
FAR TO DROP LOWS THIS PERIOD AS CLOUDS MAY REMAIN DUE TO A
DEPARTING SHORTWAVE TROUGH AND WINDS ACROSS CENTRAL NEBRASKA STAY
BREEZY. LOCATIONS OVER THE PANHANDLE SHOULD SEE THE COLDEST
TEMPERATURES AS SKIES CLEAR AND WINDS DECREASE.
TEMPERATURES ARE FORECAST TO BE NEAR NORMAL FOR TUESDAY ALTHOUGH
WARM AID ADVECTION WILL START UP AGAIN DURING THE DAY. THIS REALLY
DOESN/T KICK IN UNTIL LATER IN THE DAY SO WON/T BE TOO QUICK TO
RAISE HIGHS.
LONG TERM...WEDNESDAY THROUGH SATURDAY
THIS PERIOD OF THE FORECAST CONTINUES TO SEE MUCH UNCERTAINTY AS
IT RELIES HEAVILY ON THE PLACEMENT OF A SURFACE FRONTAL BOUNDARY
TO DELINEATE WHERE THE MUCH COLDER TEMPERATURES WILL BE IN PLACE
WHILE LOCATIONS TO THE SOUTH OF THE FRONT WILL SEE CONDITIONS STAY
ABOVE NORMAL. ALTHOUGH THERE ARE DIFFERENCES BETWEEN MODEL
SOLUTIONS...THE MAIN CONSENSUS IS TO KEEP THE COLDER (-20C OR
COLDER AIR AT 850MB OVER THE DAKOTAS AND WELL NORTH OF THE
FORECAST AREA. THERE WILL BE A TIGHT TEMPERATURE GRADIENT SO AS
THIS AIR MAY COME INTO NORTHERN NEBRASKA...MAY SEE A TEMPERATURE
RANGE ACROSS THE FORECAST AREA FROM THE MID 20S TO THE MID 50S.
THE FLOW THROUGH THIS TIME WILL BE QUICK NORTHWEST FLOW AND THERE
DOES LOOK TO BE POTENTIAL FOR A QUICK SHOT OF PRECIPITATION
THURSDAY NIGHT. KEPT THE MENTION OF THIS TO THE FAR NORTHEAST
PORTIONS OF THE FORECAST AREA AS THERE IS LOW CONFIDENCE BUT HARD
TO PULL CHANCES WITH SEVERAL MODEL SOLUTIONS PUSHING A TROUGH
ACROSS THE AREA.
FIRE WEATHER...
ALTHOUGH DEWPOINTS ARE FORECAST TO SLOWLY RISE THROUGH THE
DAY...THE COMBINATION WITH THE ABNORMAL WARM TEMPERATURES WILL
DROP RELATIVE HUMIDITY DOWN TO 15 TO 25 PERCENT ACROSS MUCH OF
WESTERN AND NORTH CENTRAL NEBRASKA. FUELS CONTINUE TO BE PRIMED
FOR BURNING DUE TO THE LACK OF PRECIPITATION OVER THE LAST SEVERAL
WEEKS SO THOSE WITH FIRE CONCERNS ARE URGED TO PAY CLOSE ATTENTION
TO CURRENT CONDITIONS AT YOUR SITE. WINDS LOOK TO STAY BELOW RED
FLAG WARNING CRITERIA SO WILL TO EXPECT NEAR CRITICAL CONDITIONS
FOR FIRE WEATHER. ALSO...EVEN IF A SITE OR TWO DOES HIT RED FLAG
CRITERIA...DON/T EXPECT IT TO LAST 3 HOURS OR MORE SO WILL STICK
WITH NO HAZARD PRODUCT FOR FIRE WEATHER CONCERNS TODAY.
HYDROLOGY...
ICE JAM PROBLEMS CONTINUE ALONG THE NORTH PLATTE RIVER BETWEEN
LEWELLEN AND LAKE MCCONAUGHY. THE WARM TEMPERATURES TODAY MAY HELP
TO BREAK UP SOME OF THE ICE AND ALLEVIATE THE FLOODING...HOWEVER
THE COLD /BELOW FREEZING/ TEMPERATURES FORECAST FOR THE FIRST FEW
DAYS OF THE WORK WEEK WILL LIKELY CAUSE MORE BUILDUP OF ICE TO
PROLONG THE ICE JAM FLOODING IN THIS AREA. IN ADDITION...OTHER
AREAS ALONG THE NORTH PLATTE RIVER MAY SEE ICE JAMMING OCCUR THIS
WEEK.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...JACOBS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
712 AM CST SUN JAN 15 2012
.UPDATE...
.SHORT TERM...
A LOOK AT THE MORNING UA FLIGHTS FROM LBF...UNR AND DNR AS WELL AS
THE RUC...GEM REG AND HRRR FORECAST TEMPS SUGGESTED RAISING 1ST
PERIOD MAX TEMPS A FEW DEGREES. WITH DEEPER VERTICAL MIXING TO
850 MB THESE TEMPS SHOULD BE REACHABLE AND STRONGER WINDS NEAR THE
BREEZY CATEGORY SHOULD DEVELOP AS WINDS AT H850 ARE FCST TO REACH 30
TO 35 KTS.
THE HRRR SUGGESTED RED FLAG CONDITIONS BUT A BLEND OF HRRR AND
DRIER MAV GUIDANCE USING THE WARMER HIGHS ONLY PRODUCED RH NEAR 20
PERCENT SO THE UPDATED FCST DOES NOT INCLUDE A RED FLAG WARNING.
.PREV DISCUSSION... /ISSUED 519 AM CST SUN JAN 15 2012/
UPDATE...
AVIATION...
VFR IS EXPECTED TODAY. AN ARCTIC FRONT WILL DROP THROUGH THE
FORECAST AREA TONIGHT. CURRENT INDICATIONS ARE MVFR CIGS COULD
DEVELOP FROM NORTH TO SOUTH AFTER 09Z.
PREV DISCUSSION... /ISSUED 400 AM CST SUN JAN 15 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
FORECAST CONCERNS THROUGH THIS PERIOD DEAL WITH SNOW CHANCES
MONDAY AND MONDAY NIGHT AS WELL AS TEMPERATURES THROUGHOUT THE PERIOD.
AT 08Z WATER VAPOR IMAGERY SHOWED RIDGING OVER THE CENTRAL AND
NORTHERN PLAINS AS A SHORTWAVE TROUGH MOVED INTO THE PACIFIC
NORTHWEST WITH AN ENHANCED BIT OF ENERGY PLACED OVER SOUTHERN SASKATCHEWAN.
MEANWHILE ANOTHER CIRCULATION WAS OBSERVED OFF THE CALIFORNIA
COAST IN THE SOUTHERN STREAM. CLOSER TO HOME...THERE WERE A FEW
CLOUDS SEEN OVER THE FORECAST AREA EARLY THIS MORNING MOVING OVER
THE RIDGE...AND WITH WARM AIR PUSHING IN...TEMPERATURES STAYED
MILD FOR THIS TIME OF YEAR. AT 08Z...OBSERVATIONS INDICATED MID
20S TO LOW 30S ACROSS MUCH OF NEBRASKA. PLENTIFUL WARM AIR
ADVECTION HAS BEEN TAKING PLACE OVERNIGHT AS COMPARING LAPS
SOUNDINGS TO THE KLBF SOUNDING FROM 15.00Z WOULD SHOW AN INCREASE
IN TEMPERATURES BETWEEN 800 TO 850MB OF AROUND 9 DEGREES FROM 00Z
TO 07Z.
BUFKIT FORECAST SOUNDINGS FROM BOTH THE NAM/GFS ARE NOT HANDLING THE
WARM AIR PATTERN FOR TODAY WELL AS THEY FAILED TO MIX OUT THE
BOUNDARY LAYER THIS AFTERNOON. THIS HAS BEEN A PROBLEM IN THE PAST
WHICH HAS FORECASTED TEMPERATURES MUCH TOO COLD...SO DID NOT LOOK AT
THESE MODELS FOR TEMPERATURES TODAY. FROM THE FORECAST SOUNDINGS
ASSUMING MIXING TO 850 OR 875MB WOULD BRING TEMPERATURES THIS
AFTERNOON INTO THE 60S ACROSS MUCH OF SOUTHWEST INTO CENTRAL
NEBRASKA. THESE NUMBERS WILL BE WELL ABOVE NORMAL...BUT DON/T
EXPECT TO REACH RECORD NUMBERS TODAY. CONFIDENCE ROSE IN THAT LAST
STATEMENT AS STANDARDIZED ANOMALY DATA SHOWED 850MB TEMPERATURES
AT 1.5 STANDARD DEVIATIONS ABOVE NORMAL. WOULD LIKE THAT TO BE
HIGHER IF FORECASTING RECORD NUMBERS. WINDS AT THE TOP OF THE
MIXED LAYER WILL ONLY BE 15 TO 20KTS SO DON/T EXPECT WINDS TO BE
TOO STRONG TODAY. THIS IS A POSITIVE IN TERMS OF FIRE WEATHER
CONCERNS AS RELATIVE HUMIDITY WILL BE LOW TODAY. SEE FIRE WEATHER
DISCUSSION BELOW FOR MORE DETAILS.
AS TODAY PROGRESSES...THE SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST WILL MOVE EAST TOWARDS THE NORTHERN ROCKIES WITH THEA
SHORTWAVE TROUGH OVER SASKATCHEWAN WILL MOVE EAST ACROSS SOUTHERN
CANADA. THIS WILL LEAD TO A SURFACE FRONT CENTERED OVER SOUTHERN
CANADA TO ALSO MOVE EAST...DRAGGING ALONG A COLD FRONT ACROSS THE
PLAINS. THE TIMING OF THE FRONT WILL BE TO MOVE INTO NORTHWEST
NEBRASKA LATER THIS AFTERNOON...SO HIGH TEMPERATURES SHOULD SEE
LITTLE AFFECT FROM COLDER AIR COMING SOUTH.
TEMPERATURES TONIGHT WILL DROP SIGNIFICANTLY AS HIGH PRESSURE
BUILDS IN FROM THE NORTH TO WEAKEN THE WINDS AND PUSH ANY CLOUDS
OUT OF THE AREA /ESPECIALLY OVER THE PANHANDLE/. ONGOING FORECAST
IS A BIT WARMER THAN SOME STATISTICAL GUIDANCE...WITH THE
UNCERTAINTY IN THE DROP OFF OF WINDS TO IMPACT THE FORECAST LOWS.
THE MAIN PACIFIC NORTHWEST SHORTWAVE WILL PASS ACROSS THE ROCKY
MOUNTAINS BY MONDAY MORNING AND INTO THE NORTHERN AND CENTRAL
PLAINS THROUGH THE DAY MONDAY. THIS SYSTEM WILL BRING SNOW CHANCES
TO THE FORECAST AREA FOR MONDAY AND MONDAY NIGHT. DID BACK OFF A
BIT ON SNOW CHANCES MONDAY MORNING AS A SUBSTANTIAL DRY LAYER
LOOKS TO BE IN PLACE ACCORDING TO CROSS SECTIONS AND FORECAST
SOUNDINGS TO SLOW THE ONSET OF PRECIPITATION AS THE COLUMN
SATURATES. HIGHEST CHANCES ARE GOING TO COME AFTER 18Z MONDAY
THROUGH 17.06Z AS THE COLUMN IS SATURATED AND COMBINES WITH THE
STRONGEST UPPER LEVEL DYNAMICS AS WELL A FRONTOGENESIS SIGNAL IN
THE 700 TO 600MB LAYER. THE SYSTEM AS A WHOLE WILL HAVE QUITE A
BIT OF MOISTURE WITH IT...BUT A GREAT DEAL OF THAT MOISTURE WILL
BE SQUEEZED OUT AS IT OVERPASSES THE MOUNTAINS. THUS ONLY LOOKING
FOR LIGHT SNOW AMOUNTS FOR MONDAY AND MONDAY NIGHT. AS MUCH COOLER
AIR WILL BE IN PLACE ALOFT...HIGHS MONDAY WILL BE SOME 30 DEGREES
COOLER THAN WHAT OCCURRED SUNDAY. MONDAY NIGHT IS LOOKING TO BE
THE COLDEST NIGHT OF THE WEEK AS 850MB TEMPERATURES DROP TO 12 TO
15 DEGREES BELOW ZERO. THERE DOES REMAIN SOME UNCERTAINTY TO HOW
FAR TO DROP LOWS THIS PERIOD AS CLOUDS MAY REMAIN DUE TO A
DEPARTING SHORTWAVE TROUGH AND WINDS ACROSS CENTRAL NEBRASKA STAY
BREEZY. LOCATIONS OVER THE PANHANDLE SHOULD SEE THE COLDEST
TEMPERATURES AS SKIES CLEAR AND WINDS DECREASE.
TEMPERATURES ARE FORECAST TO BE NEAR NORMAL FOR TUESDAY ALTHOUGH
WARM AID ADVECTION WILL START UP AGAIN DURING THE DAY. THIS REALLY
DOESN/T KICK IN UNTIL LATER IN THE DAY SO WON/T BE TOO QUICK TO
RAISE HIGHS.
LONG TERM...WEDNESDAY THROUGH SATURDAY
THIS PERIOD OF THE FORECAST CONTINUES TO SEE MUCH UNCERTAINTY AS
IT RELIES HEAVILY ON THE PLACEMENT OF A SURFACE FRONTAL BOUNDARY
TO DELINEATE WHERE THE MUCH COLDER TEMPERATURES WILL BE IN PLACE
WHILE LOCATIONS TO THE SOUTH OF THE FRONT WILL SEE CONDITIONS STAY
ABOVE NORMAL. ALTHOUGH THERE ARE DIFFERENCES BETWEEN MODEL
SOLUTIONS...THE MAIN CONSENSUS IS TO KEEP THE COLDER (-20C OR
COLDER AIR AT 850MB OVER THE DAKOTAS AND WELL NORTH OF THE
FORECAST AREA. THERE WILL BE A TIGHT TEMPERATURE GRADIENT SO AS
THIS AIR MAY COME INTO NORTHERN NEBRASKA...MAY SEE A TEMPERATURE
RANGE ACROSS THE FORECAST AREA FROM THE MID 20S TO THE MID 50S.
THE FLOW THROUGH THIS TIME WILL BE QUICK NORTHWEST FLOW AND THERE
DOES LOOK TO BE POTENTIAL FOR A QUICK SHOT OF PRECIPITATION
THURSDAY NIGHT. KEPT THE MENTION OF THIS TO THE FAR NORTHEAST
PORTIONS OF THE FORECAST AREA AS THERE IS LOW CONFIDENCE BUT HARD
TO PULL CHANCES WITH SEVERAL MODEL SOLUTIONS PUSHING A TROUGH
ACROSS THE AREA.
AVIATION...
VFR IS EXPECTED TODAY AND TONIGHT. AN ARCTIC FRONT IS EXPECTED TO
DROP THROUGH THE FORECAST AREA TONIGHT. CURRENT INDICATIONS ARE MVFR
CIGS WILL NOT DEVELOP UNTIL AFTER 12Z MONDAY MORNING.
FIRE WEATHER...
ALTHOUGH DEWPOINTS ARE FORECAST TO SLOWLY RISE THROUGH THE
DAY...THE COMBINATION WITH THE ABNORMAL WARM TEMPERATURES WILL
DROP RELATIVE HUMIDITY DOWN TO 15 TO 25 PERCENT ACROSS MUCH OF
WESTERN AND NORTH CENTRAL NEBRASKA. FUELS CONTINUE TO BE PRIMED
FOR BURNING DUE TO THE LACK OF PRECIPITATION OVER THE LAST SEVERAL
WEEKS SO THOSE WITH FIRE CONCERNS ARE URGED TO PAY CLOSE ATTENTION
TO CURRENT CONDITIONS AT YOUR SITE. WINDS LOOK TO STAY BELOW RED
FLAG WARNING CRITERIA SO WILL TO EXPECT NEAR CRITICAL CONDITIONS
FOR FIRE WEATHER. ALSO...EVEN IF A SITE OR TWO DOES HIT RED FLAG
CRITERIA...DON/T EXPECT IT TO LAST 3 HOURS OR MORE SO WILL STICK
WITH NO HAZARD PRODUCT FOR FIRE WEATHER CONCERNS TODAY.
HYDROLOGY...
ICE JAM PROBLEMS CONTINUE ALONG THE NORTH PLATTE RIVER BETWEEN
LEWELLEN AND LAKE MCCONAUGHY. THE WARM TEMPERATURES TODAY MAY HELP
TO BREAK UP SOME OF THE ICE AND ALLEVIATE THE FLOODING...HOWEVER
THE COLD /BELOW FREEZING/ TEMPERATURES FORECAST FOR THE FIRST FEW
DAYS OF THE WORK WEEK WILL LIKELY CAUSE MORE BUILDUP OF ICE TO
PROLONG THE ICE JAM FLOODING IN THIS AREA. IN ADDITION...OTHER
AREAS ALONG THE NORTH PLATTE RIVER MAY SEE ICE JAMMING OCCUR THIS
WEEK.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1040 PM EST MON JAN 16 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE TO SOUTHERN MICHIGAN BY TUESDAY MORNING,
THEN CONTINUE TRACKING NORTHEAST INTO SOUTHEASTERN CANADA BY THE
AFTERNOON. THIS SYSTEM WILL BRING A LIGHT WINTRY MIX TO THE
REGION OVERNIGHT...INCLUDING SOME FREEZING RAIN. THE MIXED
PRECIPITATION WILL CHANGE OVER TO RAIN TUESDAY MORNING AS WARMER
AIR WORKS INTO THE AREA. A STRONG COLD FRONT WILL SWEEP THROUGH
TUESDAY EVENING...WITH GUSTY NORTHWEST WINDS THAT WILL PERSIST
INTO WEDNESDAY MORNING. LAKE EFFECT SNOW IS LIKELY SOUTHEAST OF
LAKE ONTARIO LATE TUESDAY NIGHT THROUGH EARLY WEDNESDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATE AS OF 1030 PM...JUST TWEAKED POPS...TEMPS TO REFLECT ON-
GOING RADAR TRENDS. SECOND WAVE OF PRECIP WAS RAPIDLY DEVELOPING
AND TRACKING TO THE EAST AND SHUD OVERSPREAD ALL OF THE REGION BY
6Z. 00Z NAM SUGGESTS PRECIP TYPE SHUD REMAIN MAINLY SNOW ACRS NC
NY...UNTIL 9Z OR SO...AND A MIX OF ZR/IP REST OF NE PA AND SC NY
...EXCEPT ALONG THE LAKE ONTARIO PLAIN WHERE DOWNSLOPING SHUD KEEP
SFC TEMPS ABV FREEZING DESPITE EVAP COOLING. THE PRECIP WILL BE
LIGHT SO NOT EXPECTING MUCH SNOW IN NC NY...1 TO 3 INCHES AT
BEST. REST OF AREA...LIGHT ICING MAINLY.
PREVIOUS DSCN BELOW...
RADAR SHOWS PRECIPITATION RAPIDLY DEVELOPING ACROSS NEW YORK AND
PENNSYLVANIA IN RESPONSE TO DEEP LAYER ISENTROPIC LIFT. CROSS-
SECTIONS REVEAL A LAYER ALMOST 400 MB THICK OF ISEN LIFT MAINLY
BTWN 900 AND 500 MB. LOOKING AT THE BIG PICTURE...THERE APPEARS TO
BE AT LEAST TWO WAVES OF PRECIPITATION INITIALLY. THE FIRST IS
DEVELOPING PRECIPITATION QUICKLY ACROSS EASTERN NY...WITH THE NEXT
ONE QUICKLY WORKING INTO WRN PA/SW NY ATTM. THE WAVE IN WRN PA/WRN
NY WILL LEAD TO WIDESPREAD LIGHT PRECIPITATION ACROSS ALL OF C NY
AND NE PA BTWN 3 AND 6Z THIS EVENING. IN THE GRIDS...I BASICALLY
EXTRAPOLATED UP TO CAT POPS FROM 30-40 POPS BY 6Z ACROSS ENTIRE
CWA.
AS FOR P-TYPE...I USED A 50-50 BLEND OF THE GFS AND NAM THICKNESS
TOOL IN GFE WHICH CAPTURES THE CHANGEOVER VERY WELL. THIS WAS USED
ON PREVIOUS SHIFT AND IT STILL LOOKS VERY MUCH ON TRACK. BIGGEST
QUESTION IS HOW MUCH SNOW WILL FALL ACROSS THE NERN PART OF
CWA AS 18Z NAM...18Z GFS...18Z LOCAL WRF AND LATEST RUC ALL
INDICATE FROM 1-3 INCHES OF SNOW AT KRME. GIVEN THE COLDER TEMP
PROFILES AND THE RAPIDLY DEVELOPING PRECIPITATION ATTM...THIS
LOOKS GOOD. REST OF AREA LESS THAN 1 INCH OF SNOW AND SLEET. SINCE
QPF AMNTS ARE NOT THAT HIGH I DON/T EXPECT MUCH MORE THAN A SMALL
COATING OF ICE IN CWA...HIGHEST WILL BE CATSKILLS TO UPR MOHAWK
VALLEY WHERE MAYBE .1 TO .2 INCHES OF ICE ACCUMS. EVENTHOUGH TEMPS ARE
ABV FREEZING IN PARTS OF THE CENTRAL SRN TIER/FINGER
LAKES...DEWPOINTS ARE LOW ENUF THAT EVAP COOLING FROM PRECIPITATION
SHUD DROP TEMPS TO BELOW FREEZING. THIS OCCURRED IN PA THIS EVE AND
I SEE NO REASON WHY IT WON/T HAPPEN IN THE FINGER LAKES IN THE
NEXT COUPLE HOURS.
DECIDED TO HAVE ADVY IN EFFECT ALL AREAS AT 7 PM...AND WILL DROP
THE FINGER LAKES AREA BY ARND 3 AM...AS I BELIEVE FZRA WON/T LAST
THAT LONG. I ALSO BROKE OUT ONEIDA CO INTO ANTHR WSWSEGMENT TO HIT
THE SNOW A LITTLE HARDER. I ALSO ADDED SOME PATCHY FOG INTO THE
GRIDS ONCE THE SFC TEMPS GET CLSE TO AND ABV FRZG.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...AREA WILL RESIDE IN WARM SECTOR, AS SFC LOW PRES TRACKS
THROUGH NEARBY SOUTHERN ONTARIO CHANGING ALL REMAINING MIXED
PRECIP OVER ERN/NRN SECTIONS TO JUST RAIN BY MID MORNING. LIGHT
RAIN WILL CONTINUE THROUGH THE DAYTIME PERIOD WITH COVERAGE
GENERALLY DECREASING BY LATE AFTERNOON.
TUESDAY NIGHT...A STRONG COLD FRONT MOVES THROUGH THE AREA BETWEEN
00Z-06Z. MODEL SOUNDINGS AND ISALLOBARIC RISE/FALL COUPLET
INDICATE THE POTENTIAL FOR FREQUENT WINDS GUSTS AROUND 40 MPH,
ESPECIALLY ALONG THE LAKE PLAIN AND IN THE WESTERN CATSKILLS. A
WIND ADVISORY MAY BE NEEDED BY LATER SHIFTS. SCATTERED RAIN
SHOWERS WILL CHANGE TO SNOW SHOWERS IMMEDIATELY BEHIND FRONT IN
STRONG CAA. AFTER 09Z, LES PARAMETERS BECOME FAVORABLE UNDER 280
FLOW. WILL CONTINUE WITH CAT POPS ACROSS ONEIDA COUNTY TOWARD
MORNING.
WEDNESDAY...LOW LEVEL FLOW VEERS TO AROUND 300 DEGREES BY 15Z WITH
T85 AROUND -16C. WENT WITH CAT POPS ACROSS ONONDAGA/MADISON/
ONEIDA COUNTIES WITH POPS LOWERING INTO THE CHC CATEGORY BY MID
AFTERNOON AS SYNOPTIC MOISTURE DECREASES ALONG WITH SFC RIDGING.
WITH FAVORABLE LES CONDITIONS FOR 12 HOURS ACCUMS WILL LIKELY
REQUIRE AN ADVISORY. (3-7 INCHES).
TEMPS ON WEDNESDAY WILL ONLY RISE A FEW DEGREES UNDER GOOD LOW
LEVEL CAA. MAXES WILL RANGE IN THE 20S.
WEDNESDAY NIGHT...SFC HIGH PRES WILL RESIDE OVER THE AREA WITH
MAINLY CLEAR TO PARTLY CLOUDY SKIES. LOW TEMPS WILL RANGE AROUND
ZERO IN THE EAST/NORTH TO THE TEENS PARTS WEST.
THURSDAY...SFC LOW PRES MOVING THROUGH THE UPPER GREAT LAKES ALONG
WITH A DECENT MID LEVEL TROF MAY SPREAD SNOW SHOWERS OVER THE
REGION DURING THE AFTERNOON. POPS WILL BE HIGHER WEST. MAXES WILL
RANGE IN THE MID 20S TO AROUND 30.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNSETTLED WEATHER WITH LOW AMPLITUDE NEAR ZONAL FLOW. NO BIG STORMS
EXPECTED WITH TEMPERATURES AT OR ABOVE NORMAL. THURSDAY NIGHT A COLD
FRONT GOES THROUGH. THIS TIME ALL PRECIPITATION WILL BE SNOW WITH
THE COLD AIR ENTRENCHED OVER THE NE US WITH THE UPPER LEVEL TROF.
FRIDAY ANOTHER BRIEF PERIOD OF LAKE EFFECT BEFORE HIGH PRESSURE
MOVES IN LATE FRIDAY AND FRIDAY EVENING. ANOTHER QUICK STORM MOVES
EAST NORTHEAST FROM THE SOUTHERN MISSISSIPPI VALLEY TO THE MID
ATLANTIC STATES SATURDAY THEN OFF THE NEW ENGLAND COAST SUNDAY. FOR
NOW THIS DOES NOT LOOK LIKE A BIG STORM...AND ONLY BRUSHES THE AREA
WITH LIGHT SNOW. FOR SUNDAY TO MONDAY WARM AIR ADVECTION AHEAD OF A
STRONG COLD FRONT IN THE PLAINS AND DEEP UPPER LEVEL TROF OVER THE
ROCKIES. WE COULD HAVE SOME WEAK LIGHT OVERRUNNING MIXED
PRECIPITATION WITH NUMEROUS SHORT WAVES AND WARM FRONTS LIFTING
NORTHEAST BUT FOR THE MOST PART SHOULD REMAIN DRY AND MILD.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
630 PM UPDATE...
VFR CONTINUES BUT LIGHT MIXED SHOWERS HAVE MOVED IN AND MVFR CIGS
ON THE DOORSTEP. THIS EVENING CIGS WILL FALL TO MVFR BY 4Z BUT
VSBYS SHOULD STAY VFR AT LEAST TO START. WITH STEADIER PRECIP
STARTING AROUND MIDNIGHT VSBYS WILL FALL TO MVFR WITH CIGS FALLING
TO LOWER END OF MVFR. COULD BE SOME IFR VSBYS IN SLEET AND
FREEZING RAIN WITH THE SNOW COVER IN NY. BY 12Z CIGS FALL TO IFR
MOST LOCATIONS BUT WITH PRECIP CHANGING TO RAIN VSBYS SHOULD RISE
TO MVFR.
WITH A STRONG LOW LEVEL JET MOVING ACROSS THE TERMINALS THIS
EVENING...HAVE KEPT LLWS AT ALL TERMINALS WITH WINDS AROUND 2KFT
EXPECTED TO BE AROUND 45 KTS. THIS SHOWS UP WELL ON OUR RADAR.
ALSO SEVERAL PILOT REPORTS OF TURBULANCE REPORTED. BEST TIME
FRAME FOR THE LLWS WILL BE UP TO 06Z NY TERMINALS...AND UNTIL 08Z
AT KAVP.
AT THE SURFACE SOUTH WINDS AROUND 10 KTS WITH STILL SOME GUSTS TO
20 AT BGM AND ITH FIRST 2 HOURS. LATE TONIGHT INTO TUESDAY NOT
MUCH CHANGE WITH SOUTH WINDS AT 8 TO 10 KTS. KRME WILL HAVE VALLEY
ESE WIND AT 5 TO 10 KTS UNTIL TUESDAY AFTN AT LEAST.
.OUTLOOK...
TUESDAY NIGHT TO WEDNESDAY...MVFR/IFR RESTRICTIONS IN RAIN SHOWERS
CHANGING TO SNOW SHOWERS. ALSO...STRONG NORTHWEST WINDS WITH
GUSTS REACHING AT LEAST 25-35 KTS.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR BUT SOME SNOW SHOWERS AND MVFR
POSSIBLE IN NY. IMPROVING TO VFR EVERYWHERE THU AFTN.
THU NGT TO FRIDAY...MVFR. LIGHT SNOW CHANGING TO LAKE EFFECT SNOW
IN NY.
SATURDAY...MVFR IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR PAZ038>040-
043-044-047-048-072.
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR NYZ009-024-
036-037-044>046-055>057-062.
WINTER WEATHER ADVISORY UNTIL 3 AM EST TUESDAY FOR NYZ017-018-
022-023-025.
&&
$$
SYNOPSIS...DJN/RRM
NEAR TERM...DJN
SHORT TERM...RRM
LONG TERM...TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
728 PM EST MON JAN 16 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE TO SOUTHERN MICHIGAN BY TUESDAY MORNING,
THEN CONTINUE TRACKING NORTHEAST INTO SOUTHEASTERN CANADA BY THE
AFTERNOON. THIS SYSTEM WILL SPREAD A LIGHT WINTRY MIX ACROSS THE
REGION BY LATE EVENING...INCLUDING SOME FREEZING RAIN. THE MIXED
PRECIPITATION WILL CHANGE OVER TO RAIN TUESDAY MORNING AS WARMER
AIR WORKS INTO THE AREA. A STRONG COLD FRONT WILL SWEEP THROUGH
TUESDAY EVENING...WITH GUSTY NORTHWEST WINDS THAT WILL PERSIST
INTO WEDNESDAY MORNING. LAKE EFFECT SNOW IS LIKELY SOUTHEAST OF
LAKE ONTARIO LATE TUESDAY NIGHT THROUGH EARLY WEDNESDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
RADAR SHOWS PRECIPITATION RAPIDLY DEVELOPING ACROSS NEW YORK AND
PENNSYLVANIA IN RESPONSE TO DEEP LAYER ISENTROPIC LIFT. CROSS-
SECTIONS REVEAL A LAYER ALMOST 400 MB THICK OF ISEN LIFT MAINLY BTWN 900
AND 500 MB. LOOKING AT THE BIG PICTURE...THERE APPEARS TO BE AT
LEAST TWO WAVES OF PRECIPITATION INITIALLY. THE FIRST IS DEVELOPING
PRECIPITATION QUICKLY ACROSS EASTERN NY...WITH THE NEXT ONE QUICKLY
WORKING INTO WRN PA/SW NY ATTM. THE WAVE IN WRN PA/WRN NY WILL
LEAD TO WIDESPREAD LIGHT PRECIPITATION ACROSS ALL OF C NY AND NE
PA BTWN 3 AND 6Z THIS EVENING. IN THE GRIDS...I BASICALLY EXTRAPOLATED
UP TO CAT POPS FROM 30-40 POPS BY 6Z ACROSS ENTIRE CWA.
AS FOR P-TYPE...I USED A 50-50 BLEND OF THE GFS AND NAM THICKNESS
TOOL IN GFE WHICH CAPTURES THE CHANGEOVER VERY WELL. THIS WAS USED
ON PREVIOUS SHIFT AND IT STILL LOOKS VERY MUCH ON TRACK. BIGGEST
QUESTION IS HOW MUCH SNOW WILL FALL ACROSS THE NERN PART OF
CWA AS 18Z NAM...18Z GFS...18Z LOCAL WRF AND LATEST RUC ALL
INDICATE FROM 1-3 INCHES OF SNOW AT KRME. GIVEN THE COLDER TEMP
PROFILES AND THE RAPIDLY DEVELOPING PRECIPITATION ATTM...THIS
LOOKS GOOD. REST OF AREA LESS THAN 1 INCH OF SNOW AND SLEET. SINCE
QPF AMNTS ARE NOT THAT HIGH I DON/T EXPECT MUCH MORE THAN A SMALL
COATING OF ICE IN CWA...HIGHEST WILL BE CATSKILLS TO UPR MOHAWK
VALLEY WHERE MAYBE .1 TO .2 INCHES OF ICE ACCUMS. EVENTHOUGH TEMPS ARE
ABV FREEZING IN PARTS OF THE CENTRAL SRN TIER/FINGER
LAKES...DEWPOINTS ARE LOW ENUF THAT EVAP COOLING FROM PRECIPITATION
SHUD DROP TEMPS TO BELOW FREEZING. THIS OCCURRED IN PA THIS EVE AND
I SEE NO REASON WHY IT WON/T HAPPEN IN THE FINGER LAKES IN THE
NEXT COUPLE HOURS.
DECIDED TO HAVE ADVY IN EFFECT ALL AREAS AT 7 PM...AND WILL DROP
THE FINGER LAKES AREA BY ARND 3 AM...AS I BELIEVE FZRA WON/T LAST
THAT LONG. I ALSO BROKE OUT ONEIDA CO INTO ANTHR WSWSEGMENT TO HIT
THE SNOW A LITTLE HARDER. I ALSO ADDED SOME PATCHY FOG INTO THE
GRIDS ONCE THE SFC TEMPS GET CLSE TO AND ABV FRZG.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...AREA WILL RESIDE IN WARM SECTOR, AS SFC LOW PRES TRACKS
THROUGH NEARBY SOUTHERN ONTARIO CHANGING ALL REMAINING MIXED
PRECIP OVER ERN/NRN SECTIONS TO JUST RAIN BY MID MORNING. LIGHT
RAIN WILL CONTINUE THROUGH THE DAYTIME PERIOD WITH COVERAGE
GENERALLY DECREASING BY LATE AFTERNOON.
TUESDAY NIGHT...A STRONG COLD FRONT MOVES THROUGH THE AREA BETWEEN
00Z-06Z. MODEL SOUNDINGS AND ISALLOBARIC RISE/FALL COUPLET
INDICATE THE POTENTIAL FOR FREQUENT WINDS GUSTS AROUND 40 MPH,
ESPECIALLY ALONG THE LAKE PLAIN AND IN THE WESTERN CATSKILLS. A
WIND ADVISORY MAY BE NEEDED BY LATER SHIFTS. SCATTERED RAIN
SHOWERS WILL CHANGE TO SNOW SHOWERS IMMEDIATELY BEHIND FRONT IN
STRONG CAA. AFTER 09Z, LES PARAMETERS BECOME FAVORABLE UNDER 280
FLOW. WILL CONTINUE WITH CAT POPS ACROSS ONEIDA COUNTY TOWARD
MORNING.
WEDNESDAY...LOW LEVEL FLOW VEERS TO AROUND 300 DEGREES BY 15Z WITH
T85 AROUND -16C. WENT WITH CAT POPS ACROSS ONONDAGA/MADISON/
ONEIDA COUNTIES WITH POPS LOWERING INTO THE CHC CATEGORY BY MID
AFTERNOON AS SYNOPTIC MOISTURE DECREASES ALONG WITH SFC RIDGING.
WITH FAVORABLE LES CONDITIONS FOR 12 HOURS ACCUMS WILL LIKELY
REQUIRE AN ADVISORY. (3-7 INCHES).
TEMPS ON WEDNESDAY WILL ONLY RISE A FEW DEGREES UNDER GOOD LOW
LEVEL CAA. MAXES WILL RANGE IN THE 20S.
WEDNESDAY NIGHT...SFC HIGH PRES WILL RESIDE OVER THE AREA WITH
MAINLY CLEAR TO PARTLY CLOUDY SKIES. LOW TEMPS WILL RANGE AROUND
ZERO IN THE EAST/NORTH TO THE TEENS PARTS WEST.
THURSDAY...SFC LOW PRES MOVING THROUGH THE UPPER GREAT LAKES ALONG
WITH A DECENT MID LEVEL TROF MAY SPREAD SNOW SHOWERS OVER THE
REGION DURING THE AFTERNOON. POPS WILL BE HIGHER WEST. MAXES WILL
RANGE IN THE MID 20S TO AROUND 30.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNSETTLED WEATHER WITH LOW AMPLITUDE NEAR ZONAL FLOW. NO BIG STORMS
EXPECTED WITH TEMPERATURES AT OR ABOVE NORMAL. THURSDAY NIGHT A COLD
FRONT GOES THROUGH. THIS TIME ALL PRECIPITATION WILL BE SNOW WITH
THE COLD AIR ENTRENCHED OVER THE NE US WITH THE UPPER LEVEL TROF.
FRIDAY ANOTHER BRIEF PERIOD OF LAKE EFFECT BEFORE HIGH PRESSURE
MOVES IN LATE FRIDAY AND FRIDAY EVENING. ANOTHER QUICK STORM MOVES
EAST NORTHEAST FROM THE SOUTHERN MISSISSIPPI VALLEY TO THE MID
ATLANTIC STATES SATURDAY THEN OFF THE NEW ENGLAND COAST SUNDAY. FOR
NOW THIS DOES NOT LOOK LIKE A BIG STORM...AND ONLY BRUSHES THE AREA
WITH LIGHT SNOW. FOR SUNDAY TO MONDAY WARM AIR ADVECTION AHEAD OF A
STRONG COLD FRONT IN THE PLAINS AND DEEP UPPER LEVEL TROF OVER THE
ROCKIES. WE COULD HAVE SOME WEAK LIGHT OVERRUNNING MIXED
PRECIPITATION WITH NUMEROUS SHORT WAVES AND WARM FRONTS LIFTING
NORTHEAST BUT FOR THE MOST PART SHOULD REMAIN DRY AND MILD.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
630 PM UPDATE...
VFR CONTINUES BUT LIGHT MIXED SHOWERS HAVE MOVED IN AND MVFR CIGS
ON THE DOORSTEP. THIS EVENING CIGS WILL FALL TO MVFR BY 4Z BUT
VSBYS SHOULD STAY VFR AT LEAST TO START. WITH STEADIER PRECIP
STARTING AROUND MIDNIGHT VSBYS WILL FALL TO MVFR WITH CIGS FALLING
TO LOWER END OF MVFR. COULD BE SOME IFR VSBYS IN SLEET AND
FREEZING RAIN WITH THE SNOW COVER IN NY. BY 12Z CIGS FALL TO IFR
MOST LOCATIONS BUT WITH PRECIP CHANGING TO RAIN VSBYS SHOULD RISE
TO MVFR.
WITH A STRONG LOW LEVEL JET MOVING ACROSS THE TERMINALS THIS
EVENING...HAVE KEPT LLWS AT ALL TERMINALS WITH WINDS AROUND 2KFT
EXPECTED TO BE AROUND 45 KTS. THIS SHOWS UP WELL ON OUR RADAR.
ALSO SEVERAL PILOT REPORTS OF TURBULANCE REPORTED. BEST TIME
FRAME FOR THE LLWS WILL BE UP TO 06Z NY TERMINALS...AND UNTIL 08Z
AT KAVP.
AT THE SURFACE SOUTH WINDS AROUND 10 KTS WITH STILL SOME GUSTS TO
20 AT BGM AND ITH FIRST 2 HOURS. LATE TONIGHT INTO TUESDAY NOT
MUCH CHANGE WITH SOUTH WINDS AT 8 TO 10 KTS. KRME WILL HAVE VALLEY
ESE WIND AT 5 TO 10 KTS UNTIL TUESDAY AFTN AT LEAST.
.OUTLOOK...
TUESDAY NIGHT TO WEDNESDAY...MVFR/IFR RESTRICTIONS IN RAIN SHOWERS
CHANGING TO SNOW SHOWERS. ALSO...STRONG NORTHWEST WINDS WITH
GUSTS REACHING AT LEAST 25-35 KTS.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR BUT SOME SNOW SHOWERS AND MVFR
POSSIBLE IN NY. IMPROVING TO VFR EVERYWHERE THU AFTN.
THU NGT TO FRIDAY...MVFR. LIGHT SNOW CHANGING TO LAKE EFFECT SNOW
IN NY.
SATURDAY...MVFR IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR PAZ038>040-
043-044-047-048-072.
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR NYZ009-024-
036-037-044>046-055>057-062.
WINTER WEATHER ADVISORY UNTIL 3 AM EST TUESDAY FOR NYZ017-018-
022-023-025.
&&
$$
SYNOPSIS...RRM/DJN
NEAR TERM...DJN
SHORT TERM...RRM
LONG TERM...TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BUFFALO NY
716 PM EST MON JAN 16 2012
.SYNOPSIS...
INTERMITTENT RAIN AND SOME FREEZING RAIN OR DRIZZLE WELL INLAND WILL
MOVE INTO WESTERN AND CENTRAL NEW YORK TONIGHT AHEAD OF A SYSTEM
THAT WILL DEVELOP OVER THE MIDWEST OVERNIGHT. THIS LOW WILL DEEPEN
AS IT MOVES OVER THE OHIO ON TUESDAY AND DOWN THE ST LAWRENCE RIVER
VALLEY TUESDAY NIGHT. AS THE LOW PASSES TO THE NORTH OF THE REGION
LATE TUESDAY...IT WILL DRAG A COLD FRONT ACROSS NEW YORK...WITH LAKE
EFFECT SNOW TAKING SHAPE BEHIND THE FRONT SOUTHEAST OF THE LAKES
TUESDAY NIGHT AND WEDNESDAY. A BRIEF BREAK IS EXPECTED WEDNESDAY
NIGHT BEFORE A CLIPPER SYSTEM MOVES BY ON THURSDAY BRINGING ANOTHER
ROUND OF GENERAL SNOWFALL AS WELL AS LAKE LAKE EFFECT SNOW TO THE
REGION.
&&
.NEAR TERM /THROUGH TUESDAY/...
THE UPPER LEVEL PATTERN FEATURES A WEAK RIDGE IN THE EASTERN US AND
DEVELOPING TROUGH IN THE WEST. A WEAK SHORTWAVE CAN BE FOUND OVER
IL/IN QUICKLY RIDING UP THE BACK SIDE OF THE RIDGE. THE AMPLITUDE
OF THESE FEATURES IS RELATIVELY SMALL AND EXPECT THEM TO MOVE FAIRLY
QUICKLY EASTWARD OVER THE NEXT 24 HOURS. AT THE SURFACE IS A
DEVELOPING MIDWEST LOW IN RESPONSE TO THE UPPER LEVEL SHORTWAVE AT
THE BASE THE WESTERN US TROUGH.
CURRENT SATELLITE IMAGERY SHOWS ABUNDANT LOW AND MID LEVEL MOISTURE
MOVING TOWARD THE REGION...BUT RADAR IMAGERY SHOWS LITTLE
PRECIPITATION EXCEPT MAINLY OVER WESTERN PA AND THE LOWER OH VALLEY
WHERE CLOUD TOPS ARE FINALLY SHOWING SIGNS OF COOLING IN RESPONSE TO
THE IL/IN SHORTWAVE. THE LATEST SEVERAL RUNS OF THE HRRR AND RUC
AGREE WITH UPSTREAM DATA...THERE IS LITTLE REASON TO EXPECT MUCH
MORE THAN ABUNDANT CLOUD COVER TONIGHT WITH EVENTUALLY ENOUGH
MOISTURE TO SQUEEZE OUT SOME LIGHT PRECIPITATION OVERNIGHT. THUS WE
HAVE A LOW QPF BUT HIGH POP FORECAST.
FREEZING RAIN INLAND...
OVER THE SOUTHERN TIER...DUE TO A DRY INITIAL LOW LEVEL AIRMASS
EARLY THIS EVENING...EXPECT TEMPERATURES IN THE INLAND PORTIONS OF
THE SOUTHERN TIER TO DROP BELOW FREEZING TONIGHT. WITH EVENTUAL
PRECIPITATION EXPECTED...ALBEIT LIGHT AMOUNTS...A MIX OF RAIN OR
FREEZING RAIN IS POSSIBLE...MAYBE INSTEAD AS DRIZZLE OR FREEZING
DRIZZLE. WITH MINIMAL LIFT...SLEET IS PROBABLY NOT AN ISSUE...AND
SNOW SHOULD BE HARD TO COME BY WITH LITTLE LIFT...BARELY ENOUGH TO
GET ANY MOISTURE INTO THE COOLER SNOW-MAKING LAYER BELOW -10 OR SO.
WILL LET THE ADVISORY RIDE...BUT WILL ADJUST THE TIME A BIT.
IN THE WESTERN FINGER LAKES...TEMPERATURES SHOULD BE A BIT WARMER
THAN IN THE NORMALLY COOLER SOUTHERN TIER AREAS. FROM A
COORDINATION STANDPOINT WITH BGM AND THE MARGINAL NATURE OF THE
EVENT...WILL HOLD OFF ON EXPANDING THE CURRENT ADVISORY AREA AND
DESCRIBE ANY FREEZING RAIN AS A LOWER POSSIBILITY WHEN COMPARED TO
THE INLAND PORTIONS OF THE SOUTHERN TIER.
EAST OF LAKE ONTARIO...THIS AREA HAS THE HIGHEST LIKELIHOOD FOR
FREEZING PRECIPITATION AS TEMPERATURES SHOULD EASILY DROP BELOW OR
REMAIN BELOW FREEZING LATER THIS AFTERNOON AND INTO THE EVENING.
WHAT PRECIPITATION DOES BREAK OUT WILL LIKELY START OUT AS
SNOW...BEFORE TRANSITIONING TO RAIN OR FREEZING RAIN. AGAIN...QPF
WILL BE LOW...BUT THERE SHOULD BE AT LEAST SOME MIXED
PRECIPITATION. LIKE THE FINGER LAKES REGION...WILL ADJUST THE
TIMING BUT KEEP THE AREAL EXTENT UNCHANGED...WITH FREEZING RAIN A
POSSIBILITY FROM NORTHERN CAYUGA EAST.
THE REST OF THE REGION SHOULD SEE LIGHT PRECIPITATION...WITH RAIN OR
DRIZZLE OVERNIGHT ALONG WITH AREAS OF FOG AS THE SNOWPACK CONTINUES
TO MELT WITH TEMPERATURES RISING BACK TO 40F.
ON TUESDAY...A CONTINUATION OF DREARY WEATHER IS EXPECTED DURING THE
MORNING WITH A LOW QPF BUT PLENTY OF LIGHT RAIN OR DRIZZLE AND FOG
WITH CONTINUED MELTING SNOW. ANY FREEZING PRECIPITATION EAST OF
LAKE ONTARIO SHOULD TRANSITION OVER TO PLAIN RAIN OR DRIZZLE BY MID
MORNING.
THE POSSIBILITY FOR MORE SUBSTANTIAL RAIN WILL INCREASE
IN THE AFTERNOON AS THE DEEPENING OH LOW APPROACHES WITH THE REGION
UNDER THE MAIN BAROCLINIC LEAF AND UNDER THE WARM AIR CONVEYOR
BELT. THE COLD FRONT IS NOT EXPECTED TO ARRIVE UNTIL AFTER SUNSET.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
THE PERIOD BEGINS WITH A MATURE SURFACE LOW CENTERED JUST NORTH OF
LAKE ONTARIO. THE WARM FRONTAL PRECIPITATION WILL BE LIFTING OUT OF
THE NORTH COUNTRY WHILE THE TRAILING COLD FRONT WILL BE ON THE
DOORSTEP OF WESTERN NEW YORK...DRAPED ACROSS THE EASTERN PORTION OF
LAKE ERIE. THE LOW WILL QUICKLY LIFT INTO THE ST. LAWRENCE VALLEY
TUESDAY NIGHT WHILE THE COLD FRONT SWEEPS ACROSS THE REGION. STRONG
COLD ADVECTION BEHIND THE FRONT ALONG WITH A TIGHT ISALLOBARIC
GRADIENT BEHIND THE LOW WILL LEAD TO GALES ACROSS THE LAKES WITH
ADVISORY LEVEL WINDS ALSO POSSIBLE ACROSS MUCH OF THE REGION.
AS THE WINDS VEER TO THE WEST AND A ARCTIC AIR SPILLS ACROSS THE
REGION...EXPECT LAKE EFFECT SNOWS TO DEVELOP ACROSS LAKES ERIE AND
ONTARIO. WINDS WILL QUICKLY VEER FROM SOUTHWEST TO WEST MAKING THE
WINDOW FOR SNOWFALL IN THE BUFFALO METRO AREA VERY LIMITED. THE BULK
OF SNOWFALL OFF OF LAKE ERIE IS EXPECTED TO OCCUR FROM SOUTHERN ERIE
COUNTY SOUTH ACROSS THE CHAUTAUQUA RIDGE AND FROM THE TUG HILL
PLATEAU SOUTH TO WAYNE COUNTY OFF OF LAKE ONTARIO...WITH ADVISORY
LEVEL AMOUNTS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY ACROSS THE
SNOWBELTS SOUTHEAST OF THE LAKES. GIVEN THE STRONG WINDS...WINTER
WEATHER ADVISORY WILL LIKELY NEED TO BE CONSIDERED TO COVER THE
POTENTIAL FOR BLOWING SNOW. FOR NOW WILL HIGHLIGHT IN THE HWO AS
THIS IS STILL OUT IN THE THIRD TO FORTH PERIODS.
REGARDING TEMPERATURES...EXPECT THE BRIEF RESPITE FROM WINTER TO BE
CUT SHORT IN DRAMATIC FASHION WITH TEMPS DROPPING BACK INTO THE 20S
WITH TEENS OVER THE HIGHER TERRAIN OF THE SOUTHERN TIER AND NORTH
COUNTRY. THE COLD ADVECTION WILL BE ONGOING INTO WEDNESDAY AS
TEMPERATURES WILL CONTINUE TO DROP THROUGH THE DAY TO THE TEENS BY
THE AFTERNOON...WITH SINGLE DIGITS ACROSS THE NORTH COUNTRY CLOSER
TO THE COLDEST PORTION OF THE AIRMASS.
LAKE EFFECT SNOWS SHOULD TAPER OFF BY LATER IN THE DAY ON WEDNESDAY
AS HIGH PRESSURE MOVES OVER THE REGION. WE COULD SEE ANOTHER COLD
NIGHT WEDNESDAY NIGHT AS HIGH PRESSURE MOVES OVERHEAD WITH
TEMPERATURES DIPPING BELOW ZERO ACROSS THE NORTH COUNTRY. LINGERING
CLOUD COVER ACROSS WESTERN AND SOUTHERN PORTIONS OF THE FORECAST
AREA MAY KEEP TEMPS FROM CRASHING QUITE AS FAR WITH OVERNIGHT LOWS
RUNNING FROM 5 TO 15 ABOVE.
A CLIPPER LOW WILL MOVE NORTH OF THE GREAT LAKES THURSDAY INTO
THURSDAY NIGHT SWEEPING ANOTHER COLD FRONT ACROSS THE LAKES AND
BRINGING ANOTHER SHOT OF LAKE EFFECT SNOWS TO WESTERN NEW YORK
THURSDAY NIGHT INTO FRIDAY MORNING. TEMPERATURES REBOUNDING TO NEAR
CLIMATOLOGICAL NORMALS THURSDAY WILL DROP OFF AGAIN THURSDAY NIGHT
INTO FRIDAY BEHIND THE COLD FRONT WITH LOWS AGAIN RUNNING AROUND 5
TO 15 ABOVE ZERO.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE LONG TERM STARTS WITH LAKE EFFECT SNOWS TAPERING OFF AS THE
PROGRESSIVE PATTERN CONTINUES WITH HIGH PRESSURE MOVING ACROSS THE
REGION. THE GENERAL PATTERN WILL BE FOR HIGH PRESSURE OVER NEW
ENGLAND/QUEBEC TO BE UNDERCUT BY A BROAD LOW PRESSURE SYSTEM DRIVEN
BY A VIGOROUS SHORTWAVE MOVING ACROSS THE OHIO/TENNESSEE VALLEYS
FRIDAY NIGHT. HOW FAR NORTH THE ASSOCIATED BAROCLINIC ZONE AND
ASSOCIATED PRECIP GETS IS A MATTER OF DEBATE AMONGST THE MODELS WITH
THE GFS KEEPING PRECIP FARTHER SOUTH THAN EITHER THE ECMWF OR GEM.
FOR NOW WILL KEEP CHANCE POPS FRIDAY NIGHT INTO SATURDAY. MODEL
CONSENSUS/ENSEMBLES SUGGEST A WARM-UP BY THE END OF THE WEEKEND AS
BROAD SOUTHERLY FLOW DEVELOPS ACROSS THE REGION.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL DETERIORATE FAIRLY RAPIDLY FROM WEST TO EAST AS
ABUNDANT LOW AND MID LEVEL MOISTURE MOVES INTO THE REGION. RADAR
MOSAIC SHOWS A LARGE AREA OF RAIN ASSOCIATED WITH WARM ADVECTION
MOVING ACROSS LAKE ERIE AT 00Z AND EXPECT THIS RAIN SHIELD TO
SPREAD ACROSS MUCH OF THE REGION THIS EVENING. WIDESPREAD IFR
CONDITIONS ARE EXPECTED OVERNIGHT INTO TUESDAY BEFORE A COLD FRONT
SWEEPS ACROSS THE REGION TUESDAY NIGHT.
A STRONG AND PROLONGED 45 TO 50 KNOT LOW LEVEL JET BETWEEN 1K AND 2K
FEET TODAY WILL CONTINUE WITH LOW LEVEL WIND SHEAR ACROSS WESTERN AND
CENTRAL NY.
OUTLOOK...
WEDNESDAY...MVFR/VFR WITH A CHANCE OF SNOW SHOWERS.
THURSDAY...MVFR/IFR WITH SNOW LIKELY.
FRIDAY...MAINLY VFR...CHC SNOW SHOWERS SE OF BOTH LAKES.
SATURDAY...MVFR/VFR WITH A CHANCE OF SNOW SHOWERS.
&&
.MARINE...
SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE WITH A TIGHT GRADIENT
OVER THE EASTERN GREAT LAKES REGION. A DEEPENING LOW WILL MOVE
ACROSS THE LAKES TUESDAY WITH A COLD FRONT EARLY TUESDAY NIGHT WHICH
WILL LIKELY INCREASE WIND SPEEDS INTO THE GALE CATEGORY LATE TUESDAY
NIGHT OR INTO WEDNESDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR NYZ005-006.
WINTER WEATHER ADVISORY UNTIL 4 AM EST TUESDAY FOR NYZ020-021.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR LEZ040-041.
GALE WATCH FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT
FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LOZ030.
GALE WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING
FOR LOZ042>045-062>065.
SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR LOZ042>044.
SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR LOZ045.
&&
$$
SYNOPSIS...ZAFF
NEAR TERM...ZAFF
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...WCH
MARINE...ZAFF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
910 PM EST MON JAN 16 2012
.SYNOPSIS...
A RETURN FLOW OF WARMTH AND MOISTURE THROUGH TUESDAY WILL PRECEDE
A COLD FRONT LATE TUESDAY NIGHT. A WEAK SYSTEM LATE FRIDAY INTO
SATURDAY MAY BRING SOME UNSETTLED WEATHER. OTHERWISE A GRADUAL
WARMUP IS EXPECTED LATE IN THE WEEK INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 PM MONDAY...CLOUDINESS AT DIFFERENT LEVELS TO AFFECT THE
ILM CWA OVERNIGHT. WILL CARRY SKY CONDITIONS AS EITHER MOSTLY CLOUDY
OR VARIABLY CLOUDY. BEST SHOT FOR ISOLATED SHOWERS WILL EITHER BE
WELL NORTH OF THE ILM CWA OR JUST OFF THE ILM CWA COAST WITHIN AN
AREA MARKED BY SPEED CONVERGENCE. DUE TO THE INSULATING EFFECTS FROM
THE CLOUDINESS...FOG POTENTIAL WILL BE LOW. TONIGHTS MINS WILL OCCUR
PRIOR TO MIDNIGHT...WITH STEADY OR EVEN SLOWLY INCREASING TEMPS
THERE-AFTER. MODEL PARTIAL THICKNESSES...IE. NAM 1K TO 8H...INDICATE
A RISING TREND...FROM ROUGHLY 1330 EARLY THIS EVENING TO 1350 BY
DAYBREAK TUESDAY. THE INFLUX OF HIER SFC DEWPOINTS ACROSS THE ILM
CWA OVERNIGHT REMAINS THE PROBLEM CHILD. HAVE USED THE NAM SOLUTION
AS A STARTING POINT...WITH TWEAKS TO THE LOWER SIDE APPLIED
THERE-AFTER.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...TEMPERATURES WIND UP CONSIDERABLY ABOVE CLIMO
TUESDAY AFTERNOON ESPECIALLY CONSIDERING THE CONTINUED SLOWING TREND
OF THE EXPECTED LATE NIGHT FRONTAL PASSAGE. A BROAD SWATH OF
SOUTHWESTERLY FLOW ACROSS THE CAROLINAS WILL IMPORT BOTH WARMTH AND
MOISTURE TO BOLSTER AFTERNOON TEMPS IN TO THE UPPER 60S DESPITE THE
INCREASING CLOUDINESS. RAIN CHANCES NOW APPEAR TO LARGELY HOLD OFF
UNTIL LATE AT NIGHT WITH FROPA AND THESE MAY LINGER INTO THE MORNING
HOURS OF WED BUT STRONG SUBSIDENCE AND DRYING SHOULD BE UNDERWAY BY
MIDDAY. MORE SPECIFICALLY...THE MID LEVELS DRY OUT FIRST AND THIS
SHOULD SHUT OFF PRECIP BUT THE LOW LEVEL MOISTURE TRAPPED IN THE
FRONTAL INVERSION WILL LINGER INTO THE AFTERNOON ESPECIALLY OVER
EASTERN ZONES WHERE DRYING WILL OCCUR THE LATEST. SLOWER FROPA WILL
MEAN A MILD TUESDAY NIGHT WITH LOWS CLOSER TO NORMAL HIGHS FOR THE
TIME OF YEAR. STRONG CAA KICKING IN WEDNESDAY AFTERNOON WILL NOT
ONLY MINIMIZE THE RISE OFF OF TUESDAY NIGHT LOWS BUT COULD ALSO MEAN
A NON-DIURNAL CURVE WITH FALLING TEMPS IN THE AFTERNOON. SKY CLEARS
OUT WED NIGHT AND A LIGHT N WIND MAY PREVENT PERFECT RAD COOLING BUT
LOWS STILL FALLING INTO THE UPPER 20S MOST AREAS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
EXTENDED FORECAST HAS A COUPLE OF CHALLENGES AS MOST OF
THE PERIOD WILL SEE A FAST MOVING ZONAL FLOW WHICH IS ALWAYS
TROUBLESOME WITH REGARDS TO TIMING AND STRENGTH OF EMBEDDED SYSTEMS.
FIRST SYSTEM TO CONTEND WITH IS A SUBTLE SHORTWAVE MOVING ACROSS FOR
LATE FRIDAY INTO SATURDAY. GFS AND ECMWF ARE IN GENERAL AGREEMENT
ALTHOUGH THE ECMWF IS DELAYED BY ABOUT 24 HOURS. INCREASED POPS FOR
THIS TIME OUT OF RESPECT FOR THE CONTINUITY OF THE GFS. REGARDING
THE REMAINDER OF THE PERIOD...MID LEVEL RIDGING SHOULD DEVELOP
ACROSS OUR AREA WITH CONDITIONS REMAINING DRY ALTHOUGH THERE ARE
CAVEATS. THE ECMWF CONTINUES TO SHOW A CUTOFF SYSTEM MEANDERING JUST
OFF THE NORTH CAROLINA COAST WHILE THE GFS DOES NOT. THIS OF COURSE
COULD HAVE IMPLICATIONS ON THE PROLIFIC WARMTH EXPECTED. CONTINUED
TO USE AN ENSEMBLE OR A MIDDLE OF THE ROAD APPROACH WITH WARM
CONDITIONS BUT NOT EXCEEDINGLY SO.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...EXPECT GENERALLY MID-LEVEL CEILINGS THROUGH THE TAF
FORECAST PERIOD. THE EXCEPTION WILL BE EXTENSIVE LOW CLOUDS POISED
TO MOVE ONSHORE LATER THIS EVENING AND OVERNIGHT AND PERSISTING
THROUGH MID-LAT MORNING TUESDAY. CONFIDENCE IS MODERATE TO HIGH THIS
CLOUD LAYER WILL REMAIN AT LOW VFR LEVELS WITH ONLY A LOW
POSSIBILITY OF DROPPING INTO THE MVFR RANGE. OF ADDITIONAL CONCERN
TO AVIATION WILL BE THE CHANCE OF LLWS LATE TONIGHT THROUGH DAYBREAK
TUESDAY. A MODERATELY STRONG LOW-LEVEL JET OF 35 KNOTS FROM THE
SOUTHWEST AT ABOUT THE 2K LEVEL IS EXPECTED TO DEVELOP. WILL ADDRESS
THIS FURTHER IN THE 06Z TAFS.
LOW LEVEL DEWPOINTS WILL ALSO BE ON THE RISE OVERNIGHT WITH 1-2
DEGREE TEMPERATURE/DEWPOINT SPREADS BY MORNING. DESPITE THIS AM NOT
ANTICIPATING FOG DUE TO INCREASING BOUNDARY LAYER WINDS AND THE
INSULATING EFFECTS OF EXTENSIVE CLOUDINESS.
BY 15-16Z EXPECT SOUTH TO SOUTHWEST WINDS GUSTING TO 20-27 KNOTS TO
DEVELOP AS LOW CEILINGS DISSIPATE.
EXTENDED OUTLOOK...SHOWERS LIKELY LATE TUESDAY INTO WEDNESDAY
MORNING...BUT LOW CONFIDENCE FOR IFR. SLIGHT CHANCE MVFR
VISIBILITIES THURSDAY MORNING. OTHERWISE VFR.
&&
.MARINE...
.NEAR TERM /THROUGH 6 AM TUESDAY/...
AS OF 900 PM MONDAY...PLACED AMZ256 IN A SCEC COMMENCING TUE
AFTERNOON. THE 3 ZONES NORTH OF 256 ALREADY WITHIN A SCA.
HAVING LOOKED AT THE WIND DIRECTION HODOGRAPHS FOR THE VARIOUS BUOYS
ACROSS OR IN THE VICINITY OF THE ILM WATERS... THE VEERING WIND
DIRECTION TREND WILL CONTINUE. AS THE SFC RIDGE AXIS SLIDES FURTHER
OFFSHORE OVERNIGHT...WINDS WILL EVENTUALLY BECOME SSW-SW BY DAYBREAK
TUE. THE LATEST RUC AND NAM CONTINUE TO SUPPORT THIS VEERING TREND
OVERNIGHT. WILL STAY ON THE LOWER SIDE OF GUIDANCE FOR WIND
SPEEDS...MAINLY DUE TO THE OCEAN SFC BASED MARINE INVERSION ACROSS
SSTS IN THE 50S THUS PREVENTING THE WAA S-SW 30+ KT FLOW JUST OFF
THE DECK FROM MIXING DOWN TO THE OCEAN SFC. SIG. SEAS WILL RUN IN
THE 2 TO 3 FT RANGE WITH A DOMINANT 6 TO 8 SECOND PERIODS FOR THE
MAJORITY OF THE NIGHT. THE HIER WINDS AND RESULTING SEAS OFFSHORE
WILL BLEED INTO THE COASTAL WATERS WELL AFTER MIDNIGHT ...BUILDING
SEAS TO 2 TO 4 FT TOWARD DAYBREAK TUE. MODELS INDICATE THE
TIGHTENING OF THE SFC PRESSURE GRADIENT TOWARD DAYBREAK TUE... WHICH
WILL RESULT WITH INCREASING S-SSW WINDS TO A SOLID 15
KT...OCCASIONALLY REACHING 20 KT ACROSS THE OUTER WATERS ESPECIALLY
OFF CAPE FEAR WHERE SSTS HAVE WARMED INTO THE LOWER 60S. WILL
INCLUDE ISOLATED LOW TOPPED SHOWERS OVERNIGHT.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...PREFRONTAL WIND REGIME WILL CRANK UP WIND AND
SEAS TO WHERE SMALL CRAFT ADVISORY APPEARS WARRANTED FOR ALL BUT
SOUTHERNMOST ZONES. WHILE IT MAY BE FOUND THAT AMZ 256 NEEDS TO BE
ADDED IN FUTURE FORECAST RIGHT NOW IT APPEARS THAT A DISPLACED LOW
LEVEL JET AND COAST PARALLEL FLOW WILL PREVENT WIND AND SEAS
RESPECTIVELY FROM REACHING SCA REALM...FALLING INSTEAD JUST SHORT TO
WHERE SCEC HEADLINES WILL COVER. FROPA ITSELF WILL COME SOON AFTER
SUNRISE WEDNESDAY...A FEW HOURS LATER OVER SOUTHERNMOST ZONES. IT
WILL BRING AN ABRUPT VEER TO THE NW FOLLOWED BY A GRADUAL DECREASE
IN SPEEDS. THE VEER WILL ACT TO PUSH THE SCA-WORTHY SEAS OUTSIDE OF
THE 20 NM BOUNDARY SOME TIME BY MIDDAY WED...THE EXACT TIMING OF
WHICH WILL NO DOUBT BE REFINED IN FUTURE FORECASTS. CONTINUED ALBEIT
MORE GRADUAL VEERING AND DECREASING WIND SPEED/SEAS WILL ROUND OUT
THE PERIOD WED NIGHT AS HIGH PRESSURE BUILDS FROM THE WEST.
.LONG TERM/THURSDAY THROUGH SATURDAY/...
AS OF 3 PM MONDAY...CHANGEABLE CONDITIONS FOR THE MARINE COMMUNITY
DURING THE EXTENDED AS THE MID LEVEL FLOW IS ESSENTIALLY WEST TO
EAST. LIGHT AND VARIABLE FLOW EARLY WILL GIVE WAY TO A BETTER
DEFINED SOUTHWEST FLOW EARLY FRIDAY AS A FRONT MOVES QUICKLY
ACROSS TO THE NORTH. SAME SITUATION FOR LATE FRIDAY INTO SATURDAY
WITH THE WINDS A LITTLE STRONGER BASED ON FORECAST 850MB WINDS OF
CLOSE TO FIFTY KNOTS. THIS WILL PROBABLY RESULT IN A SMALL CRAFT
ADVISORY AS SEAS INCREASE ACCORDINGLY BY EARLY SATURDAY. A QUICK
OFFSHORE FLOW WILL DEVELOP LATE SATURDAY ALTHOUGH THERE MAY BE
SOME LINGERING FLAG CRITERIA SEAS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM TUESDAY TO 1 PM EST WEDNESDAY
FOR AMZ250-252-254.
&&
$$
SYNOPSIS...BACON
NEAR TERM...DOUGH
SHORT TERM...BACON
LONG TERM...KEEBLER
AVIATION...ROSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
630 PM EST MON JAN 16 2012
.SYNOPSIS...
A RETURN FLOW OF WARMTH AND MOISTURE THROUGH TUESDAY WILL PRECEDE
A COLD FRONT LATE TUESDAY NIGHT. A WEAK SYSTEM LATE FRIDAY INTO
SATURDAY MAY BRING SOME UNSETTLED WEATHER. OTHERWISE A GRADUAL
WARMUP IS EXPECTED LATE IN THE WEEK INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 PM MONDAY...FOR THIS UPDATE...CLOUDINESS AT DIFFERENT
LEVELS TO AFFECT THE ILM CWA THIS EVENING AND OVERNIGHT. WILL
CONDENSE SKY CONDITIONS TO VARIABLY CLOUDY. LATEST FORECAST TEMP AND
DEWPOINT TRENDS OVERNIGHT CONTINUE TO LOOK GOOD AND SEE NO REASON TO
TWEAK AT THIS TIME.
PREVIOUS DISCUSSION...............................................
AS OF 230 PM MONDAY...SURFACE HIGH PRESSURE AXIS ALONG THE BEACHES
WILL BE MOVING OVER OCEAN WATERS SHORTLY. DEWPOINTS ALREADY CLIMBING
AND FULL FLEDGED RETURN FLOW WILL SOON BE UNDERWAY. THE LOW-LEVEL
MOISTURE INCREASE IS DEPICTED WELL IN RH TIME-HEIGHT SECTIONS BELOW
900 MB...BUT A VERY DRY LAYER OF AIR SANDWICHED BETWEEN THE H9-H750
LEVEL IS EVIDENT THROUGH TONIGHT. MODERATELY STRONG LOW-LEVEL JET
IS DEPICTED FROM THE SW AT 35 KNOTS AT 950 MB LATE TONIGHT THROUGH
DAYBREAK TUESDAY. ONLY A FRACTION OF THIS WILL BE REALIZED AT THE
SURFACE AS A GOOD PORTION OF THE SURFACE RIDGE HANGS ON OVER LAND
AND A NOCTURNAL INVERSION DEVELOPS.
HAVE INTRODUCED LIGHT SHOWERS TONIGHT BUT ONLY OVER THE COASTAL
WATERS WHERE LOW-LEVEL CONVERGENCE WILL BE STRONGEST. THE LATEST
SATELLITE ANIMATIONS SHOW STRATO-CUMULUS CLOUDS OFFSHORE BEGINNING
TO ROTATE TOWARD THE SC COAST THIS AFTERNOON. THIS COUPLED WITH
ABUNDANT MID AND HIGH CLOUDS WILL BRING MOSTLY CLOUDY CONDITIONS
TO OUR AREA OVERNIGHT. THIS IN TURN WILL KEEP TEMPS CONSIDERABLY
ELEVATED...ALMOST 20 DEGREES MILDER THAN 24 HOURS AGO. HAVE NOT
INTRODUCED FOG DUE TO INSULATING EFFECTS OF EXTENSIVE CLOUDINESS
AND WINDS OVERNIGHT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...TEMPERATURES WIND UP CONSIDERABLY ABOVE CLIMO
TUESDAY AFTERNOON ESPECIALLY CONSIDERING THE CONTINUED SLOWING TREND
OF THE EXPECTED LATE NIGHT FRONTAL PASSAGE. A BROAD SWATH OF
SOUTHWESTERLY FLOW ACROSS THE CAROLINAS WILL IMPORT BOTH WARMTH AND
MOISTURE TO BOLSTER AFTERNOON TEMPS IN TO THE UPPER 60S DESPITE THE
INCREASING CLOUDINESS. RAIN CHANCES NOW APPEAR TO LARGELY HOLD OFF
UNTIL LATE AT NIGHT WITH FROPA AND THESE MAY LINGER INTO THE MORNING
HOURS OF WED BUT STRONG SUBSIDENCE AND DRYING SHOULD BE UNDERWAY BY
MIDDAY. MORE SPECIFICALLY...THE MID LEVELS DRY OUT FIRST AND THIS
SHOULD SHUT OFF PRECIP BUT THE LOW LEVEL MOISTURE TRAPPED IN THE
FRONTAL INVERSION WILL LINGER INTO THE AFTERNOON ESPECIALLY OVER
EASTERN ZONES WHERE DRYING WILL OCCUR THE LATEST. SLOWER FROPA WILL
MEAN A MILD TUESDAY NIGHT WITH LOWS CLOSER TO NORMAL HIGHS FOR THE
TIME OF YEAR. STRONG CAA KICKING IN WEDNESDAY AFTERNOON WILL NOT
ONLY MINIMIZE THE RISE OFF OF TUESDAY NIGHT LOWS BUT COULD ALSO MEAN
A NON-DIURNAL CURVE WITH FALLING TEMPS IN THE AFTERNOON. SKY CLEARS
OUT WED NIGHT AND A LIGHT N WIND MAY PREVENT PERFECT RAD COOLING BUT
LOWS STILL FALLING INTO THE UPPER 20S MOST AREAS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
EXTENDED FORECAST HAS A COUPLE OF CHALLENGES AS MOST OF
THE PERIOD WILL SEE A FAST MOVING ZONAL FLOW WHICH IS ALWAYS
TROUBLESOME WITH REGARDS TO TIMING AND STRENGTH OF EMBEDDED SYSTEMS.
FIRST SYSTEM TO CONTEND WITH IS A SUBTLE SHORTWAVE MOVING ACROSS FOR
LATE FRIDAY INTO SATURDAY. GFS AND ECMWF ARE IN GENERAL AGREEMENT
ALTHOUGH THE ECMWF IS DELAYED BY ABOUT 24 HOURS. INCREASED POPS FOR
THIS TIME OUT OF RESPECT FOR THE CONTINUITY OF THE GFS. REGARDING
THE REMAINDER OF THE PERIOD...MID LEVEL RIDGING SHOULD DEVELOP
ACROSS OUR AREA WITH CONDITIONS REMAINING DRY ALTHOUGH THERE ARE
CAVEATS. THE ECMWF CONTINUES TO SHOW A CUTOFF SYSTEM MEANDERING JUST
OFF THE NORTH CAROLINA COAST WHILE THE GFS DOES NOT. THIS OF COURSE
COULD HAVE IMPLICATIONS ON THE PROLIFIC WARMTH EXPECTED. CONTINUED
TO USE AN ENSEMBLE OR A MIDDLE OF THE ROAD APPROACH WITH WARM
CONDITIONS BUT NOT EXCEEDINGLY SO.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...EXPECT GENERALLY MID-LEVEL CEILINGS THROUGH THE TAF
FORECAST PERIOD. THE EXCEPTION WILL BE EXTENSIVE LOW CLOUDS POISED
TO MOVE ONSHORE LATER THIS EVENING AND OVERNIGHT AND PERSISTING
THROUGH MID-LAT MORNING TUESDAY. CONFIDENCE IS MODERATE TO HIGH THIS
CLOUD LAYER WILL REMAIN AT LOW VFR LEVELS WITH ONLY A LOW
POSSIBILITY OF DROPPING INTO THE MVFR RANGE. OF ADDITIONAL CONCERN
TO AVIATION WILL BE THE CHANCE OF LLWS LATE TONIGHT THROUGH DAYBREAK
TUESDAY. A MODERATELY STRONG LOW-LEVEL JET OF 35 KNOTS FROM THE
SOUTHWEST AT ABOUT THE 2K LEVEL IS EXPECTED TO DEVELOP. WILL ADDRESS
THIS FURTHER IN THE 06Z TAFS.
LOW LEVEL DEWPOINTS WILL ALSO BE ON THE RISE OVERNIGHT WITH 1-2
DEGREE TEMPERATURE/DEWPOINT SPREADS BY MORNING. DESPITE THIS AM NOT
ANTICIPATING FOG DUE TO INCREASING BOUNDARY LAYER WINDS AND THE
INSULATING EFFECTS OF EXTENSIVE CLOUDINESS.
BY 15-16Z EXPECT SOUTH TO SOUTHWEST WINDS GUSTING TO 20-27 KNOTS TO
DEVELOP AS LOW CEILINGS DISSIPATE.
EXTENDED OUTLOOK...SHOWERS LIKELY LATE TUESDAY INTO WEDNESDAY
MORNING...BUT LOW CONFIDENCE FOR IFR. SLIGHT CHANCE MVFR
VISIBILITIES THURSDAY MORNING. OTHERWISE VFR.
&&
.MARINE...
.NEAR TERM /THROUGH 6 AM TUESDAY/...
AS OF 630 PM MONDAY...LOOKING AT THE WIND DIRECTION HODOS FOR THE
VARIOUS BUOYS ACROSS OR IN THE VICINITY OF THE ILM
WATERS...INDICATES A CONTINUED VEERING TREND AS THE SFC RIDGE AXIS
SLIDES ACROSS THE WATERS AND OFFSHORE. LATEST RUC AND NAM CONTINUE
THIS DIRECTION TREND OVERNIGHT. WILL STAY ON THE LOWER SIDE OF
GUIDANCE FOR WIND SPEEDS...MAINLY A RESULT OF THE OCEAN BASED MARINE
INVERSION ACROSS SSTS IN THE 50S PREVENTING THE WAA SOUTHERLY FLOW
JUST OFF THE DECK FROM MIXING DOWN TO THE OCEAN SFC. SIG. SEAS WILL
RUN IN THE 2 TO 3 FT RANGE WITH A DOMINANT 6 TO 8 SECOND PERIODS FOR
THE MAJORITY OF THE NIGHT. THE SFC PG TIGHTENS TOWARD DAYBREAK TUE
WHICH WILL RESULT WITH INCREASING S-SSW WINDS AT A SOLID 15
KT...OCCASIONALLY REACHING 20 KT ACROSS THE OUTER WATERS ESPECIALLY
OFF CAPE FEAR WHERE SSTS HAVE WARMED INTO THE LOWER 60S. ISOLATED
LIGHT SHOWERS ARE POSSIBLE DURING THE PRE-DAWN HRS OF TUESDAY.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...PREFRONTAL WIND REGIME WILL CRANK UP WIND AND
SEAS TO WHERE SMALL CRAFT ADVISORY APPEARS WARRANTED FOR ALL BUT
SOUTHERNMOST ZONES. WHILE IT MAY BE FOUND THAT AMZ 256 NEEDS TO BE
ADDED IN FUTURE FORECAST RIGHT NOW IT APPEARS THAT A DISPLACED LOW
LEVEL JET AND COAST PARALLEL FLOW WILL PREVENT WIND AND SEAS
RESPECTIVELY FROM REACHING SCA REALM...FALLING INSTEAD JUST SHORT TO
WHERE SCEC HEADLINES WILL COVER. FROPA ITSELF WILL COME SOON AFTER
SUNRISE WEDNESDAY...A FEW HOURS LATER OVER SOUTHERNMOST ZONES. IT
WILL BRING AN ABRUPT VEER TO THE NW FOLLOWED BY A GRADUAL DECREASE
IN SPEEDS. THE VEER WILL ACT TO PUSH THE SCA-WORTHY SEAS OUTSIDE OF
THE 20 NM BOUNDARY SOME TIME BY MIDDAY WED...THE EXACT TIMING OF
WHICH WILL NO DOUBT BE REFINED IN FUTURE FORECASTS. CONTINUED ALBEIT
MORE GRADUAL VEERING AND DECREASING WIND SPEED/SEAS WILL ROUND OUT
THE PERIOD WED NIGHT AS HIGH PRESSURE BUILDS FROM THE WEST.
.LONG TERM/THURSDAY THROUGH SATURDAY/...
AS OF 3 PM MONDAY...CHANGEABLE CONDITIONS FOR THE MARINE COMMUNITY
DURING THE EXTENDED AS THE MID LEVEL FLOW IS ESSENTIALLY WEST TO
EAST. LIGHT AND VARIABLE FLOW EARLY WILL GIVE WAY TO A BETTER
DEFINED SOUTHWEST FLOW EARLY FRIDAY AS A FRONT MOVES QUICKLY
ACROSS TO THE NORTH. SAME SITUATION FOR LATE FRIDAY INTO SATURDAY
WITH THE WINDS A LITTLE STRONGER BASED ON FORECAST 850MB WINDS OF
CLOSE TO FIFTY KNOTS. THIS WILL PROBABLY RESULT IN A SMALL CRAFT
ADVISORY AS SEAS INCREASE ACCORDINGLY BY EARLY SATURDAY. A QUICK
OFFSHORE FLOW WILL DEVELOP LATE SATURDAY ALTHOUGH THERE MAY BE
SOME LINGERING FLAG CRITERIA SEAS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM TUESDAY TO 1 PM EST WEDNESDAY
FOR AMZ250-252-254.
&&
$$
SYNOPSIS...BACON
NEAR TERM...DOUGH/COLBY
SHORT TERM...BACON
LONG TERM...KEEBLER
AVIATION...ROSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1255 AM EST SUN JAN 15 2012
.SYNOPSIS...
A STRONG UPPER LEVEL DISTURBANCE WILL EXIT OFF THE CAROLINA COAST
THIS MORNING. HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE WEST
TODAY THROUGH MONDAY... BEFORE MOVING OFFSHORE TUESDAY... AHEAD OF
AN APPROACHING COLD FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 909 PM SATURDAY...
PROBLEM OF THE NIGHT WILL BE THE TRACK OF THE MID-UPPER VORTICITY
MAXIMUM FROM SW VA ACROSS NORTHERN/NE NORTH CAROLINA... AND THE
CHANCE OF LIGHT SNOW/FLURRIES ALONG AND NORTH OF THE TRACK.
THE LATEST WV SATELLITE DATA INDICATED THAT THE MID-UPPER LEVEL
VORTICITY MAXIMUM WAS TRACKING ESE ALONG THE WVA/VA BORDER INTO SW
VA. THE RADAR REFLECTIVITY HAS BEEN INCREASING IN COVERAGE AND IN
INTENSITY IN THE PAST FEW HOURS... MAINLY NORTH OF A LINE FROM BOONE
TO KING TO WENTWORTH. LIGHT SNOW HAS BEEN REPORTED ALONG THE BLUE
RIDGE WITH SOME LIGHT ACCUMULATIONS BEGINNING. VISIBILITIES FROM
WYTHEVILLE TO HILLSVILLE/GALAX ARE BETWEEN 3/4 AND 1 MILE WITH SNOW.
THE SUBCLOUD LAYER APPEARS TO HAVE MOISTENED UP QUICKLY AT
ELEVATIONS OF 3K FEET AND ABOVE... ALONG AND NORTH OF THE TRACK OF
THE VORT MAX. HOWEVER... OFF THE BLUE RIDGE... THE SUBCLOUD LAYER
HAS BEEN SLOWER TO MOISTEN UP. NO SNOW HAS BEEN OBSERVED IN THE
TRIAD AS OF 900 PM. IN FACT... THE REFLECTIVITY RETURNS HAVE BEEN
ONLY 5-10DBZ OVER THE WINSTON-SALEM AREA... AND THE SUBCLOUD LAYER
WAS STILL TOO DRY (20 DEGREE F) TEMPERATURE/DEW POINT TEMPERATURE
DEPRESSION AT WINSTON-SALEM AND GREENSBORO.
EXTRAPOLATION OF THE VORTICITY MAXIMUM ESE PER THE LATEST OBSERVED
DATA AND RUC SUGGESTS THAT THE FAVORED AREAS FOR SOME FLURRIES WILL
BE THE NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN. THE P-TYPE
WOULD BE SNOW SUPPORTED BY THE CURRENT BELOW FREEZING TEMPERATURE
PROFILE AT GSO... WITH THE EXCEPTION OF THE BOUNDARY LAYER... WHERE
CURRENT READINGS WERE IN THE MID 30S... AND DEW POINTS IN THE UPPER
TEENS AND LOWER 20S. PARTIALS INDICATE SNOW AS WELL ACROSS THE
NORTHERN ZONES. THE 00Z/15 JANUARY PARTIALS CAME IN AT 1503M/1299M
ON THE GSO RAOB. CHECKING PAST EVENT CASES... THERE WERE NO
MEASURABLE SNOW EVENTS AT GSO WITH THESE OBSERVED PARTIALS. THIS IS
SIMPLY BECAUSE THE OBSERVED MID LEVELS ARE VERY COLD... AND DRY...
WHICH IS COMMON WITH THESE NW FLOW SYSTEMS... WHEN THE VORT TRACKS
OVERHEAD.
WE WILL KEEP A CHANCE SNOW FLURRIES ACROSS THE NORTH (MAINLY NORTH
OF I-40 TO RALEIGH... THEN NORTH OF US-64 FROM RALEIGH TO WILSON).
THIS WILL BE ALONG AND NORTH OF THE EXPECTED TRACK OF THE VORT MAX.
STILL... THERE IS NOT EXPECTED TO BE ANY ACCUMULATION AS THE SNOW
WOULD BE TOO LIGHT.
SKIES WILL CLEAR LATER TONIGHT... IT WILL BE COLD AGAIN WITH LOWS IN
THE 20S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 305 PM SATURDAY...
SUNDAY AND SUNDAY NIGHT: A TRAILING DISTURBANCE EMBEDDED WITHIN THE
ELONGATED VORTICITY AXIS BEARING THE LEAD CLIPPER WAVE...WILL PIVOT
THROUGH THE DEPARTING BASE OF THE L/W TROUGH EARLY SUN...FOLLOWED BY
SIGNIFICANT (150M/12HR) MID LEVEL HEIGHT RISES AND THE ARRIVAL OF
STRONG (1035 MB) SURFACE HIGH PRESSURE THROUGH THE REMAINDER OF THE
WEEKEND. THIS SHOULD YIELD SKIES BECOMING SUNNY SUNDAY...WITH CLEAR
SKIES LIKELY TO CONTINUE UNTIL CIRRUS ASSOCIATED WITH A SW US UPPER
JET SPREAD INTO OUR REGION LATE SUN NIGHT. THE HIGH CLOUDS ARE
EXPECTED TO REMAIN THIN ENOUGH AND BE DELAYED SUCH THAT RADIATIONAL
COOLING CONDITIONS WILL BE EXCELLENT AND LEAD TO LOWS IN THE 21 TO
26 DEGREE RANGE. HIGHS GENERALLY 43 TO 50 DEGREES.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 255 PM...
RIDGING SURFACE AND ALOFT MONDAY MORNING. INCREASING MOISTURE IN
WEST SOUTHWEST FLOW AHEAD OF AN APPROACHING SHORT WAVE BUT WEATHER
LIMITED TO CLOUDS THROUGH MONDAY NIGHT. 850 MILLIBAR FLOW INCREASES
TO FIFTY KNOTS OR MORE BY SUNRISE TUESDAY BUT IS RELATIVELY UNIFORM
AND PERHAPS SPEED DIVERGENT. LOW LEVELS ARE STABLE AND THE PARENT
LOW TO THE TROUGH WELL NORTH IN THE EASTERN GREAT LAKES BY SUNSET
TUESDAY. THUS THIS COULD BE A SITUATION OF A VERY HIGH CHANCE FOR
VERY LITTLE RAIN TUESDAY. FORTY PERCENT CHANCE BY TUESDAY AFTERNOON
BUT THIS MAY NEED TO BE DOUBLED... BUT AGAIN FOR VERY LOW AMOUNTS.
THE SURFACE TROUGH FORECAST TO BE OFFSHORE BY SUNRISE WEDNESDAY...
AND RAIN CHANCES WILL DRY UP FROM WEST TO EAST TUESDAY NIGHT... WITH
THE REMAINDER OF THE FORECAST PERIOD DRY.
BEHIND THE FRONT SURFACE HIGH PRESSURE SETTLE OVER NORTH CAROLINA
THURSDAY MORNING... AND IS CENTERED OFFSHORE BY EVENING... NOSING
BACK INTO THE SOUTHEAST STATES. THERE IS ENOUGH AGREEMENT IN AN
UPPER LEVEL WAVE REACHING THE MOUNTAINS SATURDAY TO INTRODUCE A
CHANCE FOR RAIN.
TUESDAY IS EXPECTED TO BE BREEZY WITH SOME GUSTS TO 30 MPH.
AFTERNOON TEMPERATURES NEAR NORMAL MONDAY AT 50 TO 55... WITH RISING
TO NEAR 60 NORTHWEST TO NEAR 67 SOUTHEAST TUESDAY. HIGH TEMPERATURES
MOSTLY 45 TO 50 BEHIND THE FRONT WEDNESDAY AND THURSDAY... RISING
INTO THE FIFTIES FRIDAY... AND LOW TO MID 60S SATURDAY.
LOW TEMPERATURES AROUND 40 MONDAY NIGHT... 35 TO 45 TUESDAY NIGHT.
LOW TEMPERATURES IN THE MID 20S WEDNESDAY NIGHT... RISING INTO THE
40S FRIDAY NIGHT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1255 AM SUNDAY...
VFR CONDITIONS WILL HOLD THROUGH TODAY AND TONIGHT. A STRONG UPPER
LEVEL DISTURBANCE AND TROUGH AND ACCOMPANIED SURFACE LOW THAT ARE
NOW MOVING OVER THE AREA WILL MOVE OFF THE COAST BY MID MORNING...
ALLOWING SURFACE HIGH PRESSURE TO BUILD OVER THE REGION FROM THE
WEST... AND CLEARING OUT THE CURRENT VFR CIGS OVER MUCH OF CENTRAL
NC. FEW TO NO CLOUDS ARE EXPECTED THIS AFTERNOON AND EVENING.
SURFACE WINDS WILL BE FAIRLY LIGHT MAINLY FROM THE NW AND N.
LOOKING BEYOND 06Z TONIGHT: MID LEVEL CLOUDS WILL OVERSPREAD THE
AREA BEGINNING MONDAY MORNING WITH VFR CIGS LIKELY BY NOON. AS THE
SURFACE HIGH MOVES TO OUR EAST... DEEP SOUTHWEST FLOW WILL BRING A
GOOD CHANCE OF IFR/LIFR CONDITIONS LATE MONDAY NIGHT THROUGH TUESDAY
MORNING. THE RISK OF MVFR OR IFR CIGS WILL HOLD THROUGH TUESDAY AND
TUESDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT. VFR CONDITIONS ARE
EXPECTED TO RETURN WEDNESDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BADGETT/MWS
SHORT TERM...MWS
LONG TERM...RLH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1202 AM EST SUN JAN 15 2012
.SYNOPSIS...
A FEW CLOUDS WILL ACCOMPANY A WEAK SYSTEM OVERNIGHT. HIGH
PRESSURE WILL THEN BUILD IN FROM THE NORTH OVER THE NEXT
SEVERAL DAYS. RAIN CHANCES RETURN WITH A COLD FRONT LATE TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM SUNDAY...LATEST RUC AND NAM MODELS INDICATE A THINNING
SWATH OF MOISTURE BETWEEN 850 MB AND 500 MB ASSOCIATED WITH THE
CHANNELED UPPER LEVEL DISTURBANCE. MID LEVEL SCATTERED CLOUDS
MAY AFFECT THE NORTHERNMOST PORTIONS OF THE ILM CWA. JUST TOO DRY
FOR PCPN TO REACH THE GROUND BEFORE SUBLIMATING. THERE WILL BE A SFC
REFLECTION OF THE SFC LOW MOVING FROM THE TN-NC BORDER TO OFF CAPE
LOOKOUT BY DAYBREAK. WINDS WILL SLOWLY PICK UP OVERNIGHT... WITH SW
AHEAD OF THE LOW VEERING TO W TO NW AFTER ITS PASSAGE. TEMPERATURES
REACHED A MINIMUM EARLIER THIS EVENING AND HAVE ACTUALLY RISEN
SEVERAL DEGREES DUE TO BETTER MIXING WITH STRONGER LOW-LEVEL WINDS.
TEMPERATURES WILL BEGIN TO FALL AGAIN LATE WITH INCREASING COLD
ADVECTION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...A LARGELY MOISTURE-STARVED CLIPPER WILL BE
CROSSING THE REGION AT THE START OF THE PERIOD. A FEW RADAR ECHOES
MAY BE OBSERVED BUT ANY PRECIP WILL BE VERY HARD PRESSED TO REACH
THE GROUND. OTHERWISE VERY QUIET WEATHER THROUGH THE PERIOD. IN FACT
FORECAST SOUNDINGS SHOW THAT ONLY CLOUDS IN THE SHORT TERM WILL BE A
GRADUAL INCREASE OF CIRRUS AND EVENTUALLY CIRROSTRATUS LATE MONDAY
AND MONDAY NIGHT. AN EXITING SHORTWAVE AND SURFACE HIGH PRESSURE
BUILDING IN FROM THE NORTH WILL BRING COME CAA ON SUNDAY KEEPING
TEMPS JUST A FEW DEGREES BELOW CLIMO...GENERALLY IN THE LOW 50S.
850MB TEMPS REMAIN IN THE -2 TO -4C RANGE BUT LIGHT WINDS SHOW THAT
MIXING WILL PROBABLY ONLY DEEPEN TO ABOUT 900MB. THE SURFACE RIDGE
WILL MAKE ITS WAS OFF THE NC/VA COASTLINE LATE MONDAY ALLOWING FOR A
TURN TO THE SOUTH IN THE SURFACE AND LOWER LEVELS. OVERALL WINDS
REMAIN QUITE LIGHT HOWEVER SO SHALLOW MIXING WILL TEMPER ANY WARMUP
DESPITE THE GOOD WARMING SEEN AT 850MB. MID LEVEL FLOW REMAINS LOW
IN AMPLITUDE...NEARLY ZONAL. TWIN UPPER LEVEL JET MAXES DEVELOPING
OVER THE MIDDLE OF THE NATION WILL LEAD TO THE AFOREMENTIONED
INCREASE OF CIRRUS LEVEL MOISTURE LOCALLY ON MONDAY.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 230 PM SATURDAY...MODELS BRING FRONT AND ASSOCIATED PCPN OFF
THE COAST DURING THE EARLY PART OF THE LONG TERM FORECAST WITH HIGH
PRESSURE BUILDING INTO THE EASTERN PORTION OF THE COUNTRY WITH
COOLER TEMPS FOR THURSDAY WITH A NNE FLOW ACROSS THE REGION. HIGH
SLIDES OFF THE COAST FRIDAY WITH NICE RETURN FLOW SETTING UP BEHIND
IT WITH TEMPS MODERATING INTO THE LOWER 60S FRIDAY AND MID 60S ON
SATURDAY A GOOD 5-10 DEGREES ABOVE NORMAL. H5 PATTERN REMAINS FLAT
AND PROGRESSIVE WITH NEXT UP STREAM SHORT WAVE MOVING OUT OF THE
CENTRAL/SOUTHERN PLAINS INTO THE LOWER OHIO/TENNESSEE VALLY ON
SATURDAY. THE ECMWF IS DEEPER AND MORE AGGRESSIVE WITH THIS FEATURE
DEVELOPING A SURFACE LOW IN THE OHIO VALLEY WHILE THE GFE HAS A MORE
OPEN WAVE DEVELOPING. BOTH MODELS SHOW MOISTURE STREAMING UP FROM
THE GULF AHEAD OF THIS FEATURE WITH THE ECMWF BRINGING SOME PCPN
INTO THE CWA DURING THE DAY SATURDAY. H8 MOISTURE TRANSPORT VECTORS
INDICATE BOTH GULF AND ATLANTIC MOISTURE BEING TAP MAXIMIZED BETWEEN
18Z SAT AND 06Z SUNDAY. THE GFE/CMC NHEM 12Z MODEL RUNS ARE NOT AS
AGGRESSIVE HERE AS THE ECMWF AND IS MORE LIMITED WITH THE MOISTURE.
WITH PLENTY OF TIME YET TO ANALYZE THIS NEXT FEATURE WILL LEAN
TOWARDS THE GFE/CMC SOLUTION NOW WITH NEXT SYSTEM MOVING ACROSS THE
AREA ON SATURDAY WITH SOME PCPN.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...HIGH CONFIDENCE FOR VFR CONDITIONS THROUGH THE FORECAST
PERIOD. A WEAK SHORT WAVE AND ASSOCIATED LOW PRESSURE WILL CROSS THE
REGION THROUGH THE OVERNIGHT HOURS. ANY PRECIPITATION SHOULD STAY
NORTH OF THE TERMINALS...WITH ONLY A MID CLOUD CEILING EXPECTED.
AFTER THE VORT MOVES THROUGH...EXPECT A WIND SHIFT TO THE NORTHWEST
BY MID MORNING...AND GUSTY. SOME CU FORMATION IS POSSIBLE BY LATE
MORNING WITH FAIRLY STEEP LOW LAPSE RATES.
EXTENDED OUTLOOK...LOW CONFIDENCE IFR FOG INLAND TERMINALS EARLY
TUESDAY MORNING AND SHOWERS/TEMPO IFR LATE TUESDAY INTO WEDNESDAY.
OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1230 AM SUNDAY...NO SIGNIFICANT CHANGES NEEDED FOR THE VERY
EARLY MORNING UPDATE. PREVIOUS DISCUSSION FROM 930 PM FOLLOWS...
A QUICK MOVING CLIPPER LOW AND ASSOCIATED COLD FRONT IS PROGGED TO
MOVE ACROSS THE COASTAL WATERS BY DAYBREAK. POST FRONTAL W TO NW
WINDS WILL INCREASE TO 15 TO 25 KT BY DAYBREAK AND CONTINUE INTO
MIDDAY SUNDAY. SIGNIFICANT SEAS WILL BE RULED BY THE LOCALLY
PRODUCED WIND DRIVEN...3 TO 6 SECOND PERIOD WAVES. AND WITH AN
OFFSHORE TRAJECTORY...A RANGE OF SEAS WILL BE FORECAST. FRYING PAN
SHOALS WILL EXHIBIT WASHING MACHINE TYPE CONDITIONS...
WITH LOCALLY HIGHER WAVES LIKELY.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...NW WINDS WILL INCREASE SOME EARLY SUNDAY WITH
THE OFFSHORE EXIT OF A CLIPPER TYPE OF DISTURBANCE AT BOTH THE
SURFACE AND ALOFT. CAUTIONARY HEADLINES ARE NOT ANTICIPATED EVEN
WITH A LITTLE MIXING AS FORECAST SOUNDINGS SHOW NO HIGHER THAN 20
KNOTS THROUGH MOST OF WHAT SHOULD BE THE BOUNDARY LAYER OVER THE
MARINE ZONES...ESPECIALLY GIVEN THE COOLER SSTS OF THE NEARSHORE
WATERS. SUNDAY AFTERNOON WILL BRING A VEERING AND DECREASING WIND
REGIME AS HIGH PRESSURE BUILDS ACROSS VA AND THE GRADIENT EASES
LOCALLY. THIS SAME HIGH WILL ONLY SLOWLY MIGRATE EASTWARD FOR THE
REMAINDER OF THE SHORT TERM PERIOD ALL WHILE KEEPING A WEAK RIDGE
AXIS INTO THE COASTAL CAROLINAS. AS SUCH THE WINDS WILL REMAIN QUITE
LIGHT...GENERALLY 10KT...LEADING TO A MERE 2 FT WIND WAVE. AN
ADDITIONAL VEER TO A SOUTHERLY DIRECTION IS SLATED FOR MONDAY NIGHT
AS THE HIGH MOVES EVEN FURTHER OUT TO SEA AND A COLD FRONT REACHES
THE OH AND MS RIVER VALLEY REGIONS. AN INCREASE IN SPEED WILL ALSO
RESULT MONDAY NIGHT...GRADUALLY AT FIRST AND THEN WITH MORE VIGOR
AFTER ABOUT 06Z. SEAS COULD BUILD TO 5 FT ALONG THE EASTERN FRINGE
OF SOME OF THE ZONES NECESSITATING SCEC BUT A PEEK INTO THE LONG
TERM WOULD SUGGEST THAT A SMALL CRAFT ADVISORY WILL INSTEAD BE
HOISTED DUE TO FURTHER ANTICIPATED DETERIORATION OF CONDITIONS.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 230 PM SATURDAY...COLD FRONT APPROACHES THE WATERS ON TUESDAY
NIGHT INTO EARLY WEDNESDAY AND OFF THE COAST BY 12Z. TIGHT GRADIENT
WITH WINDS INCREASING FROM THE SW AT 20-25 KTS AHEAD OF FRONT WITH
SEAS BUILDING TO 5-7 FEET RESULTING IN SCA CRITERIA LATE TUESDAY
INTO MID DAY WEDNESDAY. ONCE FRONTS PASSES THE WINDS BACK FROM THE
SW TO WEST AND THEN BECOME MORE NORTHERLY BY 18Z WITH THE SEAS
DIMINISHING TO 3-5 FEET...2-4 FEET NEAR SHORE. WINDS WILL REMAIN
BRISK AT 15-20 KTS AND VEER TO THE NE ON THURSDAY BEFORE SLOWLY
DIMINISHING AS HIGH PRESSURE BUILDS ACROSS THE WATERS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 3 AM TO 1 PM EST SUNDAY FOR
AMZ250-252-254-256.
&&
$$
SYNOPSIS...MBB
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MAC
AVIATION...SHK
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
408 AM EST SUN JAN 15 2012
.SHORT TERM (TODAY AND TONIGHT)...
SOME LIGHT SNOW LINGERS OVER PORTIONS OF SW VA AND THE NE TN
MOUNTAINS EARLY THIS MORNING. BASED ON RADAR AND SATELLITE TRENDS
AND RUC FORECAST SOUNDINGS...THESE SHOULD BE TAPERING OFF SOON. WILL
INCLUDE A MENTION OF FLURRIES IN THESE AREAS FOR THE EARLY
MORNING...BUT WITH ACCUMULATING SNOWFALL ENDING...WILL DROP THE
WINTER WEATHER ADVISORY.
SURFACE HIGH PRESSURE WILL BE DRIFTING ACROSS THE AREA TODAY...WITH
A BUILDING RIDGE ALOFT. CLOUDS IN THE NORTH THIS MORNING WILL
GRADUALLY DECREASE...AND ALL AREAS SHOULD SEE FULL SUN BY THE
AFTERNOON. HIGHS WILL RANGE FROM THE UPPER 40S SOUTH TO MID/UPPER
30S NORTH. NEUTRAL TEMPERATURE ADVECTION DURING THE DAY WILL
TRANSITION TO SLIGHT WARM ADVECTION TONIGHT AS THE HIGH SHIFTS EAST
OF THE MOUNTAINS AND LOW PRESSURE TRACKS ACROSS THE PLAINS. HIGH
CLOUDS WILL ALSO BEGIN TO INCREASE LATE TONIGHT AHEAD OF THIS
SYSTEM.
.LONG TERM (MONDAY THROUGH SATURDAY)...HIGH PRESSURE ACROSS THE AREA
PROVIDING DRY WEATHER FOR MOST OF MONDAY. A FRONT MOVES INTO THE
AREA ON MONDAY NIGHT AND TUESDAY. WILL KEEP THE CHANCE POPS FOR BOTH
MONDAY NIGHT AND TUESDAY. IT SHOULD BE WARM ENOUGH FOR ALL LIQUID
PRECIPITATION ON MONDAY NIGHT. IT SHOULD ALSO BE BREEZY ON MONDAY
AND TUESDAY. THE FRONT IS EXPECTED TO EXIT THE REGION ON TUESDAY
NIGHT. THE PRECIPITATION COULD CHANGE TO LIGHT SNOW AS IT EXITS THE
AREA ON TUESDAY NIGHT. HIGH PRESSURE RETURNS BRINGING DRY WEATHER ON
WEDNESDAY THROUGH FRIDAY. ANOTHER FRONT TRACKING THROUGH THE REGION
ON SATURDAY. WITH STILL UNCERTAINTY ON TIMING...WILL LEAVE THE
CURRENT LOW POPS FOR SATURDAY AS IS.
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 47 28 53 44 58 / 0 0 20 60 60
KNOXVILLE MCGHEE TYSON AIRPORT, TN 42 25 52 42 55 / 10 0 20 60 60
OAK RIDGE, TN 42 25 52 42 55 / 10 0 20 60 60
TRI CITIES AIRPORT, TN 38 21 51 38 52 / 10 0 20 60 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS/GH
AREA FORECAST DISCUSSION
NWS SPOKANE WA
246 PM PST Sun Jan 15 2012
.SYNOPSIS...A cold and unstable air mass over the area will allow
for snow showers for most locations. accumulations will generally
be light...however moderate snow amounts are possible...over the
Idaho Panhandle...Blue Mountains and near the Cascade Crest. A
stronger system will arrive between Tuesday night and Wednesday.
This system will bring heavy snow to portions of the Inland
Northwest...however its precise location remains questionable at
this time.
&&
.DISCUSSION...
Tonight and Monday...Very cold and unstable upper level low will
provide the weather focus during this period. 500 mb temperatures
have fallen below -40C over the entire forecast area this
afternoon...however most of the convection thus far has occurred
in a sw-ne band of potential instability extending from the Blue
Mountains to the central Idaho Panhandle. This pattern will change
somewhat overnight as the focus shifts toward the incoming
shortwave trough centered just northeast of Portland as of 2pm. As
of 1pm...the NAM and RUC positioned this feature quite well and
both move it into the Cascades around 00z and into the SE corner
of Washington by 12z Monday morning. Although most of the snow
showers will concentrate near this feature...we cannot entirely
rule out additional showers elsewhere across the forecast area
tonight as the atmosphere will remain quite unstable with lifted
index values holding near 0...at least over the eastern third of
Washington and most of the Idaho Panhandle. Snowfall amounts will
be tricky. The heaviest amounts will generally fall near and just
northeast of the surface low track but this is where the models
diverge significantly. The 18z NAM wants to place a secondary
surface low well north of the upper level shortwave
trof...somewhere over southern Spokane County by 12z with a weaker
low near Lewiston. This does not make a whole lot of sense
considering the upper level forcing and lack of a low-level
thermal gradient. If the NAM were to verify...we`d be looking at
some 1-3" snowfall amounts from roughly Sprague to Harrison
through mid-morning. We will lean toward the more consistent
GFS/RUC and SREF solutions which keep the low much further south
and place the threat of moderate precipitation extending from the
Blue Mountains to the central Idaho Panhandle. Snowfall amounts
will generally range from 1-3" in much of this area...and support
the current batch of snow advisories for the Palouse...Camas
Prairie...and central Panhandle. The Lewiston area should also see
snow...but based on 1-2" amounts mainly falling overnight...it was
not worth expanding the advisories. Its worth noting...that while
these amounts should represent the average accumulations...given
the deep instability and lifting through the dendritic
layer...there will likely be localized amounts which are
considerably heavier. The would be better addressed via short-term
forecasts as it tough to forecast where showers will train over
any given area. The threat of snow showers will begin to wane by
late morning/early afternoon...as the air mass begins to stabilize
ahead of the next system forecast to move into the Cascades late
in the day. fx
Monday night through Wednesday night...The significant longwave
pattern change continues to influence this time interval producing
a substantial amount of precipitation, including heavy snowfall
for many locations including lowlands on Wednesday that changes
over to a wintry mix including some intervals of freezing rain
Wednesday night. All this occurs as a the very cold air mass
lingering over Eastern Washington and Northern Idaho is overrun
with a wet warm front with a well maintained tap into moderate
subtropical moisture. Before this potentially big snowfall events
unfolds the air mass remains cold and conditionally unstable and
the Jet stream/storm track placement is oriented in such a way as
to allow for nuisance mesoscale shortwave migration through it to
produce snow showers of varying areal coverage and intensity
Monday night into Tuesday. Tuesday night before the potentially
big Wednesday snowfall begins a stalled arctic air boundary
lingering just to the north of the Canadian Border that extends
down into portions of Northern Montana remains in place and allows
for deformation/squeezing between the it and the incoming wet warm
frontal zone so a a gradual transition to increased pops for
stratiform snowfall remain a valid segue for Tuesday night.
General low pressure/trof aloft with cold air remaining in place
at lower levels for most of this interval allow for forecast
temperatures to remain on the cool side of what would be
considered normal for this time of year. As far as snow
accumulation totals for Wednesday into Wednesday night...model
runs continue to suggest the potential remains for somewhere on
the order of near a foot of snow accumulation in most lowland
and valley locations with two or more feet in the mountains.
Winter storm watches issued to highlight this are listed at the
bottom of this discussion. /Pelatti
Wednesday night through Sunday...Yet another moisture-laden system
looks to take aim at the area by Thursday. Between that system and
the system Wednesday, the period of calmer weather may be
exceedingly brief. However, given model timing problems and
problems with placement and cold air entrenchment on all models,
the forecast represents a compromise of the ECMWF and GEFS mean
solutions. Both of these are substantially colder then the
operational 12z GFS, however both have exceedingly better
continuity than the GFS.
In attempting to follow some sort of blended solution, thermal
profiles ended up much colder than the GFS and favor a decaying
and retreating frontal boundary draped across the heart of the
CWA. This front will likely become a focusing mechanism for heavy
precipitation by the time Thursday rolls around. Profiles north
of the front will likely favor all snow, while along and south a
transition to either freezing rain or rain seems likely. This was
difficult to pin down given the lack of reliable soundings to look
at, however layer temperatures do suggest an elevated warm layer,
so at least the potential of freezing rain in the transition is
there from Wednesday night into Thursday. Additionally, QPF values
look even higher on Thursday at this point than they do on
Wednesday. This could mean another impressive snowfall where
precipitation remains all snow. At this time, the best estimate on
the rain/snow line will generally be just south of I-90. This
could put Spokane/Coeur D`Alene in a heavy/wet swath of snow yet
again. ECMWF and Canadian QPF suggests the heaviest QPF axis
should roughly run down I-90, with up to 0.75" during the day on
Thursday. Given the warmer profile relative to Wednesday, snow to
liquid ratios are unlikely to be impressive, however if it should
remain all snow during they day, yet another heavy snowfall is
quite possible.
By Thursday night, warmer air continues its northward advance as
Thursday`s system departs to the east. Showery and warmer
conditions persist through Friday night with almost all valley
locations seeing snow levels rise high enough to change to all
rain. This is supported by multiple models pushing 850 mb
temperatures up toward +3 to +4C for a time. By Saturday and
Saturday night, cold air again filters into the region with
unstable snow showers likely becoming the ruler of the region by
the weekend. /Fries
&&
.AVIATION...
18Z TAFS: The two trouble spots through most of this forecast will
be KLWS and KPUW as these two areas will remain subject to the
best chance of -shsn and ocnl MVFR cigs and vsbys through the pd.
Not too confident that many showers will hit either airport
through the day...but aft 04z or so things should pick up and IFR
conditions are a good bet as the upper level low near the area. As
the low tracks into SE WA later tonight...conditions could also
deteriorate aft 06z at KGEG KSFF and KCOE...however the chances are
not as good as KPUW and KLWS. I did place as the IFR/MVFR cigs and
vsbys as the prevailing conditions but may need to back off if low
continues to drop any further southeast. The NAM would say stay
the course...however the GFS and now the HRRR are suggesting
to trend to better conditions. The low will pass over KMWH and
KEAT with a few -shsn but conditions should generally remain in
the VFR category. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 16 28 21 31 18 29 / 30 20 50 40 100 100
Coeur d`Alene 17 29 20 30 17 29 / 40 30 60 60 100 100
Pullman 20 29 24 31 25 35 / 70 70 60 60 100 100
Lewiston 24 34 26 36 28 39 / 70 70 40 50 100 100
Colville 13 28 18 30 11 26 / 20 20 60 60 70 90
Sandpoint 17 29 21 29 12 26 / 60 60 90 90 70 100
Kellogg 18 24 18 27 21 30 / 90 90 90 90 100 100
Moses Lake 13 32 15 35 20 28 / 30 20 20 20 90 100
Wenatchee 14 28 19 31 18 26 / 40 20 20 20 80 100
Omak 2 21 12 28 10 22 / 20 20 30 30 80 80
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Storm Watch from Tuesday evening through Wednesday
evening for Central Panhandle Mountains-Coeur d`Alene Area-
Idaho Palouse-Lewis and Southern Nez Perce Counties-
Lewiston Area-Northern Panhandle.
Winter Weather Advisory until 10 AM PST Monday for Idaho Palouse-
Lewis and Southern Nez Perce Counties.
Winter Weather Advisory until 1 PM PST Monday for Central
Panhandle Mountains.
WA...Winter Storm Watch from Tuesday evening through Wednesday
evening for Lower Garfield and Asotin Counties-Moses Lake
Area-Northeast Blue Mountains-Northeast Mountains-Okanogan
Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-
Washington Palouse-Waterville Plateau-Wenatchee Area.
Winter Weather Advisory until 10 AM PST Monday for Washington
Palouse.
Winter Storm Watch from late Monday night through Wednesday
evening for East Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1149 AM PST Sun Jan 15 2012
.SYNOPSIS...A cold upper level low will park over the Pacific
Northwest for the next several days. Unstable air associated with
this low will bring snow showers to most locations. accumulations
will generally be light...however moderate snow amounts are
possible...over the Idaho Panhandle...Blue Mountains and near the
Cascade Crest. A much stronger system will arrive between Tuesday
night and Wednesday. This system will bring heavy snow to portions of
the Inland Northwest...however its precise location remains
questionable at this time.
&&
.DISCUSSION...
rest of today...cold core upper level low will toward the Inland
Northwest through the day. As of 11am...it was located near the
mouth of the Columbia River near Astoria and was drifting slowly
toward the east-southeast. 500 mb temps colder than -40C have
already filtered over most of the forecast area...however thus far
showers have been limited to a small portion of SE Washington and
the central Idaho Panhandle where the potential instability is greatest.
Daytime heating will lead to a small increase in the shower
activity over mountainous locations...however we suspect the
biggest batch of showers will arrive tonight as the core of the
upper level low swings toward the Cascades. Based on the lows
positioning...we have opted to split this afternoons weather
grid...and indicated an increase in the shower chances late in the
day near the Cascades...including the Wenatchee area and
Waterville Plateau. Given the path of the low across the southern
Washington Cascades...it seems plausible that precip chances will
be greater south of Lake Chelan than north.
As for the current batch of snow advisories...things are looking
good for much of the central Idaho Panhandle...as that is where
most of the showers will occur today. On the other hand...the
Palouse is not looking too favorable...at least through today.
Things will pick up later tonight and early Monday as the upper
level low nears...but snow amounts..at least over the Washington Palouse
may range from 1-2". Not terribly impressive...but since it has
been so long since that area has seen that much snow...we will
leave headline as is. fx
&&
.AVIATION...
18Z TAFS: The two trouble spots through most of this forecast will
be KLWS and KPUW as these two areas will remain subject to the
best chance of -shsn and ocnl MVFR cigs and vsbys through the pd.
Not too confident that many showers will hit either airport
through the day...but aft 04z or so things should pick up and IFR
conditions are a good bet as the upper level low near the area. As
the low tracks into SE WA later tonight...conditions could also
deteriorate aft 06z at KGEG KSFF and KCOE...however the chances are
not as good as KPUW and KLWS. I did place as the IFR/MVFR cigs and
vsbys as the prevailing conditions but may need to back off if low
continues to drop any further southeast. The NAM would say stay
the course...however the GFS and now the HRRR are suggesting
to trend to better conditions. The low will pass over KMWH and
KEAT with a few -shsn but conditions should generally remain in
the VFR category. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 19 29 21 31 18 / 20 60 60 50 40 100
Coeur d`Alene 31 18 28 20 30 17 / 20 60 70 60 60 100
Pullman 31 20 30 24 31 25 / 60 70 70 60 60 100
Lewiston 37 21 35 26 36 28 / 50 60 50 40 50 100
Colville 28 16 28 18 30 11 / 20 30 50 60 60 80
Sandpoint 30 18 26 21 29 10 / 30 70 70 90 90 80
Kellogg 27 18 25 18 27 21 / 80 90 80 90 90 100
Moses Lake 29 12 32 15 35 17 / 10 20 20 20 20 90
Wenatchee 29 16 28 19 31 17 / 20 20 20 20 20 80
Omak 24 9 26 12 28 10 / 10 20 30 30 30 80
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 1 PM PST Monday for Central
Panhandle Mountains.
Winter Weather Advisory until 10 AM PST Monday for Idaho Palouse-
Lewis and Southern Nez Perce Counties.
WA...Winter Weather Advisory until 10 AM PST Monday for Washington
Palouse.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1158 AM CST SUN JAN 15 2012
.UPDATE...CLOUD DECK STEADILY PUSHING OFF TO THE
NORTHEAST...LEAVING CLEAR SKIES IN ITS WAKE...EXCEPT FOR A FEW
CIRRUS. DECK SHOULD CLEAR NORTHEAST CORNER OF CWA BY 19Z. RUC LOW
LEVEL MOISTURE FIELDS SHOW DRIER AIR ADVECTING IN ON SOUTHERLY
FLOW SO EXPECTING FULL SUNSHINE FOR THE AFTERNOON. ON ACCOUNT OF
THE QUICKER DEPARTURE OF THE CLOUD DECK...RAISED HIGHS A TAD.
&&
.AVIATION/18Z TAFS/...A MIX OF LOW AND MID LEVEL CLOUDS LINGER
NORTHEAST OF MADISON THIS MORNING...WITH CLEARING CONTINUING TO
PUSH IN FROM THE SOUTHWEST. OTHER THAN A FEW SPOTS OF BRIEF MVFR IN THE
NORTHEAST...SHOULD SEE VFR CONDITIONS THROUGH THE REMAINDER OF
THE DAY.
MODELS CONTINUE TO SATURATE THE LOW LEVELS TONIGHT AHEAD OF AN
APPROACHING COLD FRONT. THINK STRATUS WILL DEVELOP LATE
EVENING/EARLY NIGHT...WITH CIGS POSSIBLY AS LOW AS IFR BY MORNING.
KEPT OUT MENTION OF FREEZING DRIZZLE IN THE TAFS AS PROBABILITY IS
ON THE LOW SIDE WITH THE MOISTURE EXPECTED TO BE QUITE SHALLOW.
IF THINGS SATURATE A BIT DEEPER THAN EXPECTED...MAY NEED TO
CONSIDER ADDING FOR LATE EVENING AND OVERNIGHT.
LOW CLOUDS EXPECTED TO LINGER THROUGH THE DAY MONDAY...ESPECIALLY
FROM AROUND MADISON AND EASTWARD.
&&
.PREV DISCUSSION... /ISSUED 330 AM CST SUN JAN 15 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM.
EXPECT AREA OF LOW STRATUS OVER SOUTHERN WISCONSIN TO GRADUALLY
ERODE AND PUSH TO THE EAST TODAY AS SOUTH WINDS
INCREASE...WEAKENING INVERSION...HOWEVER CLOUDS WL PROBABLY HANG
ON THROUGH THE MRNG IN THE EAST. STRONG LOW LEVEL WARM AIR
ADVECTION WL LIKELY BRING MORE MID/HIGH OVER THE AREA THRU THE
DAY. SHORT TERM GUIDANCE IN GOOD AGREEMENT ON CARRYING
INTENSIFYING LOW PRESSURE OVER SRN CANADA NEXT 24 HOURS. WHILE MID
LAYERS EXPECTED TO REMAIN DRY...INCREASING SOUTH WINDS WL PULL
DEEPER LOW LEVEL MOISTURE BELOW 4K FEET NORTHWARD INTO SRN WI.
THIS DEEPER MOISTURE WILL INTERACT WITH INCREASING LOW LEVEL
CONVERGENCE ALONG APPROACHING SURFACE COLD FRONT TO RESULT IN MORE
STRATUS DEVELOPING OVERNIGHT TNGT. ENOUGH LOW LEVEL CONVERGENCE
AND SHEAR AT THE TOP OF THE CLOUD LAYER TO POSSIBLY SHAKE OUT SOME
LIGHT FREEZING DRIZZLE TONIGHT. BESIDES INCREASING LOW LEVEL
RH...00Z 4KM WRF ALSO SHOWS SUBSTANTIAL INCREASE IN TOTAL COLUMN
CONDENSATE OVERNIGHT. NAM 280 THETA SFC SHOWS CONDENSATION
PRESSURE DEFICITS DECREASE TO LESS THAN 10MB OVER NORTHWEST CWA
WITH 2 TO 5 MICROBARS OF ISENTROPIC OMEGA. HENCE WL GO WITH A SCHC
FOR -ZR IN THE NORTHWEST WITH -ZL ELSEWHERE.
SHORT TERM...MONDAY THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE
MEDIUM.
COLD FRONT MOVES SOUTHEAST THROUGH THE AREA ON MONDAY. AHEAD OF
THE FRONT...AREA FORECAST SOUNDINGS FROM NAM...AND TO A LESSER
EXTENT THE GFS...SHOW MOIST LOW LEVEL AIRMASS BELOW INVERSION. TOP
DOWN FLOWCHART YIELDS FREEZING DRIZZLE POTENTIAL IN THE
MORNING...WITH SURFACE TEMPERATURES STILL AT OR BELOW FREEZING.
FOR NOW...ONLY MENTIONED PATCHY LIGHT FREEZING DRIZZLE AND AREAS
OF FOG IN THE FAR SOUTHEAST AND FAR SOUTH MONDAY MORNING SOUTHEAST
OF THE FRONT...WHERE BEST SHOT AT THESE CONDITIONS EXIST. MAY HAVE
TO BE EXPANDED NORTHWESTWARD PER NAM FORECAST SOUNDINGS IN FUTURE
FORECASTS.
AREA OF LOW LEVEL FRONTOGENESIS FOCUSES ACROSS NORTHEAST ILLINOIS
LATER ON MONDAY...AS THE COLD FRONT STALLS ACROSS THAT AREA. FAR
SOUTHEAST AND FAR SOUTHERN COUNTIES CLOSE ENOUGH TO THIS AREA TO
KEEP SLIGHT CHANCES FOR LIGHT RAIN/LIGHT SNOW...ALONG WITH AREAS
OF FOG. AIR COLUMN NOT SATURATED THROUGH A DEEP LAYER YET...SO
THIS COULD BE MORE OF A DRIZZLE SITUATION. HIGHS SHOULD REACH THE
MID 30S ACROSS THE AREA.
SHORT TERM MODELS CONTINUE TO TAKE WEAK SURFACE LOW FROM NORTHEAST
MISSOURI TO SOUTHERN LOWER MICHIGAN MONDAY NIGHT...THEN FURTHER
AWAY FROM THE AREA TUESDAY. 850MB TO 700MB FRONTOGENESIS LAYER
MOVES THROUGH THE FAR SOUTHEAST COUNTIES MONDAY NIGHT...WITH THE
MAIN SHORTWAVE TROUGH MOVING THROUGH THE AREA TUESDAY. THIS
FEATURE REMAINS AN OPEN WAVE DURING THIS TIME.
WENT WITH LIKELY POPS FOR LIGHT SNOW IN THE FAR SOUTHEAST MONDAY
NIGHT...WITH LOWER POPS TO THE NORTHWEST. SOME QUESTION AS TO HOW
LONG AIR COLUMN WILL TAKE TO SATURATE DURING THIS TIME...AS
NAM/GFS FORECAST SOUNDINGS SHOWING SOME DRY AIR IN THE 850MB TO
500MB LAYER. TEMPTED TO LOWER POPS MONDAY NIGHT...BUT WILL KEEP
THEM AND SEE IF FUTURE MODEL RUNS CONTINUE TO SHOW DRY AIR IN THE
LOW TO MID LEVELS.
CONTINUED TO MENTION LIKELY POPS FOR LIGHT SNOW TUESDAY. PRESSURE
GRADIENT INCREASES AND ALLOWS FOR GUSTY NORTHWEST WINDS AND COLD
AIR ADVECTION ACROSS THE AREA. COLD AIR ADVECTION SHOULD BRING
SNOW TO LIQUID RATIOS UP INTO THE TEENS TO PERHAPS 20 TO 1 AS THE
DAY GOES ON. HAVE A GENERAL 1.5 TO 2.0 INCHES OF SNOW EXPECTED
ACROSS THE AREA. THIS SHOULD IMPACT THE TUESDAY MORNING COMMUTE.
WILL CONTINUE TO MENTION IN HAZARDOUS WEATHER OUTLOOK FOR NOW.
HIGH PRESSURE RIDGE WILL SHIFT INTO THE AREA TUESDAY
NIGHT...BRINGING A QUICK END TO THE LIGHT SNOW FROM WEST TO EAST
BY EVENING. COLDER TEMPERATURES WILL INVADE THE AREA...AND WITH A
FRESH SNOW COVER SHOULD DROP LOWS TUESDAY NIGHT TO AROUND ZERO OR
JUST BELOW ZERO IN MOST AREAS.
LONG TERM...WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE
MEDIUM.
FAIRLY ACTIVE WEATHER PATTERN CONTINUES THROUGH THIS PERIOD...WITH
SEVERAL SYSTEMS MOVING THROUGH THE REGION. GFS/ECMWF SHOWING
SYSTEM CLIPPING THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY...SO
KEPT POPS GOING FOR THAT PERIOD. THEY DIFFER QUITE A BIT WITH THE
END OF THE WEEK SYSTEM...SO WENT WITH CONSENSUS POPS AND
TEMPERATURES AFTER THURSDAY.
AVIATION/12Z TAFS/...
MVFR CLOUD SHIELD OVER MOST OF SRN WI LINGERING FROM WEAK LOW
LEVEL FLOW AND MID LEVEL DISTURBANCE WL CONTINUE TO SLOWLY ERODE
FROM THE WEST TODAY AND SLIDE EWD DUE TO INCREASING LOW LEVEL
SOUTH WINDS. STRONG WARM AIR ADVECTION SHOULD STILL BRING A PERIOD
OF MID/HIGH CLOUDS TODAY AFTER LOW CLOUDS THIN. INCREASING SOUTH
WINDS WILL PULL DEEPER LOW LEVEL MOISTURE NORTHWARD DURING THE
DAY. AS IT INTERACTS WITH APPROACHING LOW LEVEL CONVERGENCE ZONE
ASSOCIATED WITH APPROACHING SURFACE FRONT...LOW STRATUS IS
EXPECTED TO DEVELOP OVER THE AREA TONIGHT. ENOUGH LIFT MAY BE
AVAILABLE TO CAUSE SOME PATCHY -ZL OVERNIGHT...WITH THE BEST
CHANCE AT KMSN CLOSER TO BETTER CONVERGENCE. WL INCLUDE WINDSHEAR
REMARK IN 12Z TAFS AS WINDS AT 2K FEET EXPCD TO INCREASE TO 50KTS
TNGT.
MARINE...
A TIGHTENING PRESSURE GRADIENT IS STILL EXPECTED TO DEVELOP OVER
SOUTHERN LAKE MI TODAY AND CONTINUE THROUGH TONIGHT AHEAD OF
STRENGTHENING LOW PRESSURE IN SOUTHERN CANADA. THE RELATIVELY
WARMER WATERS OF LAKE MICHIGAN WILL RESULT IN STEEP LOW LEVEL
LAPSE RATES...WHICH WILL ALLOW STRONGER WINDS TO MIX DOWN TO THE
LAKE SURFACE. FEW GUSTS TO AROUND 33KTS ARE EXPECTED
TONIGHT...ESPECIALLY TOWARD THE OPEN WATER. HENCE WILL LET SMALL
CRAFT ADVY RUN ITS COURSE AND GO INTO EFFECT LATER THIS
MRNG...CONTINUING INTO MONDAY MRNG. WIND SPEEDS WL DIMINISH AS
FRONTAL BOUNDARY SLIDES SOUTHWARD ACROSS THE LAKE ON MONDAY...BUT
SHOULD PICK UP AGAIN AS LOW PRESSURE MOVES ALONG THIS FRONT TO THE
SOUTH OF THE LAKE ON TUE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 9 AM CST MONDAY FOR LMZ643>646.
&&
$$
UPDATE...WIMBERLEY/DDV
TODAY/TONIGHT AND AVIATION/MARINE...MBK
MONDAY THROUGH SATURDAY...WOOD
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1054 PM CST SAT JAN 14 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE AND ADDED MENTION OF
LAKE EFFECT TRENDS OVER LK MICHIGAN TO THE UPDATE SECTION
.UPDATE...HAVE MADE A COUPLE FUTILE ATTEMPS TO ADJUST SKY COVER AND
TEMPS THIS EVENING...BUT UNLESS CLOUDS INCREASE QUICKLY OVER FAR NE
WI...TEMPS WILL LIKELY DROP SEVERAL DEGREES BLO ZERO THERE. WHERE
CLOUDS HAVE ALREADY THICKENED OVER THE SW TWO-THIRDS OF THE CWA...
TEMPS HAVE GENERALLY REMAINED STEADY OR WARMED BACK INTO THE UPPER
SINGLE DIGITS/LOWER TEENS. MAY ALSO NEED TO CONSIDER WARMING
TEMPS MORE LATE TONIGHT... ESPECIALLY OVER C WI...SOME LLVL WAA IS
ANTICIPATED. CURRENT READINGS ARE IN THE UPPER TEENS OVER WSTRN
WI. MAY NEED TO TAKE ONE MORE STAB AT SKY COVER/TEMPS BEFORE
LEAVING AT 11 PM.
MESO-LOW OVER CNTRL LK MICH WAS HELPING TO DEVELOP A PATCH OF
HEAVY SNOW SNOW SHOWERS OVER MID-LAKE LATE THIS EVG...BUT LLVL
WINDS ARE EXPECTED TO EVENTUALLY TURN SW OVERNIGHT...WHICH SHOULD
KEEP IT OFFSHORE FROM DOOR COUNTY. MIDNIGHT SHIFT WILL NEED TO
WATCH CLOSELY THOUGH...AS IT MAY GET PRETTY CLOSE TO SHORE.
KIECKBUSCH
&&
.PREV DISCUSSION...ISSUED AT 551 PM CST SAT JAN 14 2012...
SHORT TERM...TONIGHT AND SUNDAY.
THE SURFACE PRESSURE PATTERN OVER THE REGION WAS CAUSING SOME
ISSUES IN THE SHORT TERM. 20Z ANALYSIS SHOWED WEAK LOW PRESSURE
OVER LAKE MICHIGAN...A WEAK RIDGE OVER WISCONSIN AND A TROUGH
ACROSS MINNESOTA.
CONVERGENCE OVER THE LAKE RESULTED IN A BAND OF LAKE EFFECT SNOW
SHOWERS THAT PUSHED WEST INTO DOOR COUNTY. THE 15Z RUC APPEARED TO
HAVE A DECENT HANDLE ON THE SITUATION AS IT WAS SHOWING QPF IN THE
EASTERN PART OF THE FORECAST AREA INTO THIS EVENING. WENT WITH
SOME POPS IN THE EAST FOR THE EVENING BUT DRY THERE AFTER 06Z.
NOT REALLY SURE WHAT WAS CAUSING THE LIGHT SNOW AND FLURRIES IN
CENTRAL WISCONSIN TODAY DIRECTLY UNDER THE SURFACE RIDGE...POSSIBLY
SOME WEAK SHORT WAVE ENERGY PASSING THROUGH THE STATE. THE
VISIBILITY IN SOME LOCATIONS WENT AS LOW AS 3 MILES WITH SNOW AT
TIMES.
ANOTHER AREA OF LIGHT SNOW...WITH VISIBILITIES BELOW 2 MILES...WAS
ASSOCIATED WITH A WARM FRONT ACROSS MINNESOTA...AND A SHEARED UPPER
LEVEL SHORT WAVE. MODELS HAD THE FRONT DECAYING...THE SHORT WAVE
ENERGY MOVING SOUTHEAST THIS EVENING AND HAD QPF DRYING UP BEFORE
REACHING THE FORECAST AREA. HAVE SOME SLIGHT CHANCE POPS FOR
CENTRAL WISCONSIN DURING THE EVENING...BUT NOTHING AFTER 06Z.
TIME/HEIGHT SECTIONS FROM MODELS HAD QUITE A BIT OF LOW LEVEL
MOISTURE WITH LITTLE LIFT LATE TONIGHT...MAINLY IN THE NORTH. SO
HAVE INCLUDED A SLIGHT CHANCE OF FREEZING DRIZZLE OR FLURRIES
THERE 06Z-12Z SUNDAY.
PLENTY OF CLOUDS TONIGHT...BUT THINK THAT TEMPERATURES SHOULD FALL
INTO THE SINGLE DIGITS IN MOST LOCATIONS. WARMER THAN NORMAL HIGHS
RETURN ON SUNDAY IN STRONG WARM ADVECTION AHEAD OF THE SURFACE
SYSTEM APPROACHING FROM THE WEST. MODELS STILL HAD PLENTY OF
CLOUDS SO DID NOT GO TOO MUCH ABOVE GUIDANCE HIGHS.
EXPECT WINDS TO STEADILY INCREASE DURING THE DAY ON SUNDAY AHEAD
OF THE APPROACHING SYSTEM.
LONG TERM...MONDAY THROUGH NEXT SATURDAY.
NOT MUCH CHANGE TO THE IDEA OF DEVELOPMENT OF HIGH AMPLITUDE
RIDGING OVER THE BERING STRAIT WITH NRN STREAM ENERGY DIGGING SE
THRU ALASKA/WRN CANADA. THIS RESULTS IN DEVELOPING BROAD UPPER
TROF ACROSS SRN CANADA/NRN CONUS. THE MEAN FLOW UNDER THIS TROF TO
BE NEAR ZONAL FROM THE US...BRINGING SEVERAL RELATIVELY WEAK
SYSTEMS ACROSS THE WRN GREAT LAKES.
AT BEGINNING OF PERIOD...LOW PRESSURE MOVES EAST INTO CNTRL
ONTARIO SUNDAY NGT AND DRAGS COLD FRONT INTO CNTRL WI BY 12Z MONDAY. IT
STILL APPEARS THAT GULF MOISTURE WILL NOT HAVE TIME TO REACH THE
FORECAST AREA PRIOR TO THE FRONTAL PASSAGE. FRONT EXISTS REGION BY
EARLY IN THE AFTERNOON...THEN SHORT WAVE TROF APPROACHES FROM THE W.
SNOW SHOULD DEVELOP ALONG TIGHT BAROCLINIC ZONE ACROSS THE AREA BY
EARLY TUESDAY. ALL MODELS IN GENERAL AGREEMENT WITH DEVELOPMENT OF SFC
WAVE ALONG THE FRONT. ACCUMULATIONS SHOULD BE GENERALLY
MINOR...LESS THAN 2 INCHES THRU TUE. SOME LAKE EFFECT LINGERS IN
LAKE SUPERIOR SNOW BELT OF FORECAST AREA INTO TUE NIGHT. MIDWEEK
TEMPS WILL BE BELOW NORM AS ARCTIC AIR BRIEFLY FINDS A HOME.
SMALL CHANCES FOR SNOW SHOWERS ACROSS AREA AS WEAK RIPPLES IN WNW
UPPER FLOW CONTINUE TO MOVE ALONG BAROCLINIC ZONE. BOTH THE 14/12Z
GFS AND ECMWF TARGET FRIDAY AS THE BEST SNOW CHANCE IN THE SECOND
HALF OF THE WEEK WITH SHORT WAVE TROF MOVING ACROSS MIDWEST AND
SURFACE LOW MOVING ACROSS S ILLINOIS.
&&
.AVIATION...MVFR CIGS WERE MOVG BACK INTO CENTRAL WI LATE THIS
EVENING...AND SHOULD PROGRESS EAST ACROSS THE REGION DURING THE
OVERNIGHT HOURS...REACHING THE LKSHR BY DAYBREAK. ASIDE FROM A
FEW FLURRIES...LITTLE OR NO PCPN IS EXPECTED. VFR CONDITIONS
SHOULD RETURN TO NC/C WI BY MID MORNING...AND NE/EC WI BY AROUND
MIDDAY. HAVE ADDED SOME LLWS FOR LATE SUNDAY AFTERNOON AND
EVENING...AS SSW WINDS INCREASE TO AROUND 40 KTS 1500-2000 FT AGL.
SFC WIND GUSTS WILL ALSO BE ON THE INCREASE DURING THE LATE
AFTERNOON/EVG. SOME LOW CLOUDS MAY REDEVELOP AHEAD OF AN APPROACHING
COLD FRONT SUNDAY EVG...AND THERE IS A SMALL CHC OF SOME FREEZING
DRIZZLE. CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE A MENTION OF THE
FREEZING DRIZZLE...BUT DID INCLUDE EVENING TEMPO GROUPS FOR SOME
MVFR CIGS.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER CO
1043 PM MST MON JAN 16 2012
.UPDATE...THE AREA OF SNOWFALL HAS REGENERATED A BIT...POSSIBLY
ASSOCIATED WITH BOUNDARY LAYER CONVERGENCE. ANTICYCLONE CENTERED
NORTH OF FORT COLLINS HAS RESULTED IN SHALLOW EAST/NORTHEAST FLOW
INTERACTING WITH WEST/NORTHWEST FLOW OFF THE FOOTHILLS. WE WILL
HAVE TO DELAY THE DEPARTURE OF SNOW A COUPLE MORE HOURS TO ACCOUNT
FOR THIS.
&&
.AVIATION...SNOW HAD REDEVELOPED AT KDEN AND KAPA...AND WILL HAVE
TO EXTEND THE SNOW THERE A COUPLE MORE HOURS BASED ON LATEST RADAR
TRENDS. COULD SEE ANOTHER QUARTER INCH OR SO.
&&
.PREV DISCUSSION... /ISSUED 910 PM MST MON JAN 16 2012/
UPDATE...SNOW IS DECREASING RATHER QUICKLY AND PRETTY MUCH ON
TRACK. ONE BAND OF SNOW STILL LINGERED FROM FORT COLLINS TO
DIA...WITH ANOTHER STRETCHING FROM THE PALMER DIVIDE THROUGH EAST
CENTRAL COLORADO. MOUNTAIN AREAS HAVE ALSO SEEN SNOW DECREASE
SHARPLY LATE THIS EVENING. OVERALL FORECAST IS ON TRACK WITH SNOW
ENDING BY/SHORTLY AFTER MIDNIGHT WITH CLEARING SKIES AND COLD
TEMPERATURES OVERNIGHT.
AVIATION...SNOW IS DECREASING SO CURRENT TRENDS INDICATE SNOW
WILL BE ALL BUT GONE AT KDEN BY 06Z. KAPA AND KBJC SHOULD SEE
FLURRIES WRAP UP IN THE NEXT HOUR. THEN CEILINGS WILL GRADUALLY
LIFT AND BREAK UP BETWEEN 06Z AND 09Z.
PREV DISCUSSION... /ISSUED 453 PM MST MON JAN 16 2012/
UPDATE...LATEST RADAR SHOWS A GOOD BAND OF SNOW ASSOCIATED WITH
UPPER TROUGH AND MID LEVEL COLD FRONT SPREADING OFF THE FOOTHILLS.
WE HAVE INCREASED SNOW CHANCES FOR DENVER METRO AREA AND NORTHEAST
ACROSS THE PLAINS DUE TO THIS FEATURE...AND SHALLOW UPSLOPE
SLOWING DISSIPATION OF THE BAND IN MEAN WESTERLY FLOW ALOFT.
AVIATION...CURRENT FORECAST IS ON TRACK WITH SHOWERS SPREADING
SOUTHEAST ACROSS THE FRONT RANGE AIRPORTS FROM NOW TIL 04Z.
VISIBILITIES COULD DROP TO 1/2 MILE AND BRIEFLY 1/4 MILE IN THE
HEAVIEST SHOWERS PER UPSTREAM OBS FROM KCYS AND FORT COLLINS
SPOTTER REPORTS...SO HAVE LOWERED THE TEMPO VSBYS IN TAFS.
PREV DISCUSSION... /ISSUED 335 PM MST MON JAN 16 2012/
SHORT TERM...WIDE BAROCLINIC ZONE ASSOCIATED WITH THE UPPER TROUGH
AND SFC COLD FRONT PASSING OVER THE MOUNTAINS AT THIS HOUR. FRONTAL
BNDRY HAS MOVED THROUGH JACKSON COUNTY AS NOTED BY A SUDDEN DROP IN
TEMPERATURE AND ABRUPT SHIFT TO NORTHWEST WINDS AT WALDEN WHERE THE
TEMPERATURE FELL 11 DEGS F IN LESS THAN AN HOUR. BANDED SLANTWISE
CONVECTION...I.E. SNOWFALL...STREAKING CROSSING THE HIGH COUNTRY
JUST AHEAD OF THE 700-500MB TROUGH AXIS. HAVE NOTICED A STEADY
INCREASE IN SNOW INTENSITY AND COVERAGE IN THE PAST COUPLE OF HOURS
WITH RUC QG VERTICAL FIELDS INDICATING WEAK TO MODERATE LARGE SCALE
ASCENT CENTERED OVER THE NRN MTNS. WHERE THIS PRECIP GOES FROM HERE
AND HOW EXTENSIVE IT WILL BE DEPENDS ON WHICH MODEL YOU LOOK AT.
BOTTOM LINE...THE NAM IS DRIER AND A BIT SLOWER WITH ITS EASTWARD
PROGRESS THAN THE GFS...ECMWF AND SREF. WHEREAS...THE GFS AND SREF
SHOW A WIDER AREA OF PRECIPITATION/SNOW FIELD ACROSS NERN COLORADO
THIS EVENING...WITH A COUPLE INCHES OF SNOW ACCUM BY MIDNIGHT
ACROSS THE NORTHEAST CORNER OF THE STATE. OVERALL SEE BANDED PRECIP
TRANSLATING SOUTHWARD ACROSS THE NERN PLAINS THIS EVENING...WITH THE
BACK EDGE OF THIS PRECIP SOUTHEAST OF THE DENVER METRO AREA BY
AROUND 05Z..AND OUT OF THE CWFA (LINCOLN COUNTY) POSSIBLY BY 08Z OR
09Z TONIGHT. EXPECTED SNOW ACCUMULATION WITHIN THE I-25 URBAN
CORRIDOR MINIMAL AT BEST...PERHAPS A HALF INCH ON GRASSY SURFACES
FROM ONE OF THE HEAVIER SNOW BANDS COMING OFF THE FOOTHILLS EARLY
THIS EVENING. AGAIN...APPEARS THE NORTHEAST CORNER IN THE BEST
POSITION TO SEE ACCUMULATING SNOWFALL THIS EVENING.
LATER TONIGHT...SHOULD SEE GUSTY NORTHWEST WINDS USHERING IN DRIER
AND COLDER AIR FROM WYOMING. CLEARING LATE WILL ALLOW FOR STRONG
RADIATIONAL COOLING CAUSING TEMPERATURES TO PLUNGE WELL BELOW ZERO
IN THE HIGH MOUNTAIN VALLEYS. MIN TEMPERATURES ALSO QUITE COLD ON
THE PLAINS WITH SINGLE DIGITS ABOVE ZERO THE NORM BY MORNING LIGHT.
COULD SEE A FEW SUBZERO READINGS IN LOW LYING AREAS SUCH AS ALONG
THE SOUTH PLATTE RIVER.
ON TUESDAY...SWIFT NORTHWEST FLOW ALOFT CONTINUES OVER THE STATE
WITH A DRIER AIRMASS UPSTREAM. ANY SNOWFALL TOMORROW WILL BE
CONFINED TO THE HIGHEST PEAKS AND WEST FACING SLOPES ALONG THE
DIVIDE. EVEN THERE SNOW INTENSITIES WILL BE WEAK. TEMPERATURES WILL
STRUGGLE TO WARM TOMORROW WITH ONGOING COLD AIR ADVECTION. SEE
LITTLE CLOUD COVER ESPECIALLY EAST OF THE MTNS WITHE FLOW
REGIME.
LONG TERM...MAIN CONCERN FOR THE UPCOMING WEEK WILL BE THE HIGH
WIND POTENTIAL IN THE MOUNTAINS...FOOTHILLS AND ADJACENT PLAINS AND
DEVELOPING SNOW IN THE MOUNTAINS BY MIDWEEK. MOST OF THE WESTERN
U.S. WILL TRANSITION TO A STRONG AND ZONAL WEST TO NORTHWEST FLOW
ALOFT THIS WEEK. IT APPEARS THE STRONGEST WINDS WILL EFFECT THE
REGION LATE TUE NIGHT THROUGH EARLY THURSDAY AM AS A STRONG
130-150KT JET CORE LIFTS OUT ACROSS WYOMING ON WEDNESDAY. THE
SURFACE PRESSURE GRADIENT WILL TIGHTEN TO 10-15 MB ACROSS THE STATE
ON WED WHILE MOUNTAIN TOP STABILITY INCREASES. CROSS SECTIONS SHOW
AMPLIFIED MOUNTAIN WAVE DEVELOPING WITH 60-80KT OF CROSS BARRIER
FLOW. STILL A LOT OF QUESTION MARKS AS THERE ARE SOME CONFLICTING
PARAMETERS. THERE IS A LOT OF VERTICAL SHEAR ESPECIALLY EARLY ON
WEDNESDAY FOR AN AMPLIFIED MOUNTAIN WAVE. SHEAR PROFILE IMPROVES A
BIT BY WED NIGHT AS THE MAIN JET IS WELL EAST OF COLORADO.
HOWEVER...THE MOUNTAIN TOP LEVEL STABILITY LOOKS QUITE IMPRESSIVE AS
STRONG MID LEVEL WARMING DEVELOPS A STRONG INVERSION IN THE
700-750MB LAYER. ALONG WITH THE TIGHTENING SURFACE GRADIENT THIS
SHOULD HELP SHIFT THE STRONGER WINDS DOWN OVER THE LOWER FOOTHILLS
AND AT THE BASE OF THE FOOTHILLS. ON THE OTHER HAND...INCREASING
MOISTURE IN THE MOUNTAINS ON WEDNESDAY MAY HELP NEGATE THE STRONGEST
WINDS AND DIMINISH THE MOUNTAIN WAVE EFFECTS. STILL ENOUGH FACTORS
TO WARRANT A HIGH WIND WATCH GIVEN THE VERY STRONG MOUNTAIN TOP FLOW
AROUND 80KTS. WILL PLAY THE WATCH TIMING IN A RATHER BROAD SCOPE FOR
NOW BUT HOPEFULLY ABLE TO NAIL DOWN TIMING AND STRENGTH BETTER IN
THE NEXT FEW DAYS.
THE NEXT QUESTION WILL BE WHAT TO DO WITH ZONES 33 AND 34 IN TERMS
OF WIND VERSUS SNOW POTENTIAL...BUT THINK THE WIND WILL BE THE
BIGGEST FACTOR HERE. MOISTURE DEPTH DOES INCREASE WEDNESDAY
AFTERNOON AND NIGHT BUT GIVEN THE INCREASING STABILITY...LAPSE RATES
DECREASE TO 2.5-4C/KM BY WED NIGHT. LOCAL SNOW MODEL GENERATES UNDER
ADVISORY AMOUNTS FOR NOW. WILL AT LEAST BUMP UP POPS TO LIKELY FOR
ZONES 31 AND 33 GIVEN THE STRONG WESTERLY OROGRAPHIC FLOW.
ACROSS LOWER ELEVATIONS IT WILL BE A DRY AND A MILD WEEK AHEAD WITH
TEMPERATURES WELL ABOVE NORMAL BY MIDWEEK WITH READINGS IN THE 50S
AND LOWER 60S THROUGH THE WEEKEND.
AVIATION...COLD FRONT ALREADY SLIPPING INTO NORTHEAST COLORADO FROM
WYOMING AS OF 22Z. AS THIS FRONT MOVES SOUTH ALONG THE FOOTHILLS
SHOULD SEE BANDS OF LIGHT SNOWFALL FORMING ALONG AND BEHIND THIS
FRONTAL BOUNDARY. AT CURRENT SPEED COULD SEE THE FRONT AND ITS
ASSOCIATED SHIFT TO GUSTY NORTH-NORTHEAST WINDS IN THE NEXT 60 TO 90
MINUTES...WITH THE HEAVIER SHOWERS BEHIND THIS BOUNDARY. MVFR
CEILINGS NOW ARE EXPECTED TO LOWER TO LOWER TO BELOW 3000 FEET AGL
AFTER 00Z/TUE WIT LOCAL LIFR CEILINGS WIT PASSING SNOW SHOWERS.
HEAVIER SHOWERS COULD ALSO PRODUCE VSBYS BELOW 2 MILES. AT THIS
TIME...IT APPEARS THAT PASSING SNOW SHOWERS WILL PRODUCE MINIMAL
SNOW ACCUMULATION IN THE DENVER ARE...PROBABLY NO MORE THAN A HALF
INCH ON GRASSY SURFACES. SHOWERS ARE EXPECTED TO MOVE OUT OF THE
DENVER AREA BY AROUND 05Z THIS EVENING...AND BY 07Z...SHOULD SEE
SKIES CLEARING WITH A SURGE OF DRIER AND COLDER AIR MOVING DOWN FROM
WYOMING. ON TUESDAY...VFR CONDITIONS WITH LIGHT WEST TO SOUTHWEST
BREEZES FOR MOST OF THE DAY UNDER MOSTLY CLEAR SKIES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE TUESDAY NIGHT THROUGH THURSDAY MORNING
FOR COZ033>036-038-039.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....ENTREKIN
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1038 PM MST MON JAN 16 2012
.UPDATE...
UPPER TROF AXIS WILL CONTINUE SHIFTING EAST OF THE AREA WITH SNOW
SHOWERS QUICKLY DIMINISHING ACROSS THE CENTRAL MTS. ALREADY SEEING
A MARKED DECREASE IN ECHOES IN AREA RADARS/SAT LOOPS OUT WEST.
THUS PLAN TO LET THE WINTER WEATHER ADVISORY FOR THE SAWATCH RANGE
EXPIRE AT 11 PM. SOME LIGHT BANDED SNOW SHOWERS WILL CONTINUE
ACROSS PORTIONS OF THE SE PLAINS THROUGH MIDNIGHT BEFORE
DIMINISHING QUICKLY THEREAFTER. LITTLE TO NO ACCUMULATION IS
EXPECTED. OTHERWISE...COLD AIR WILL CONTINUE SETTLING IN ACROSS
THE PLAINS BEHIND THE FRONT. TEMPERATURES ARE ALREADY DROPPING
INTO THE SINGLE DIGITS AND LOWER TEENS ACROSS NE CO...AND SUSPECT
THAT READINGS ACROSS THE PLAINS WILL DROP INTO THE LOWER TEENS BY
MORNING. MAY TWEAK TEMPS DOWN A COUPLE DEGREES OUT EAST. ELSEWHERE
FORECAST STILL LOOKS ON TRACK WITH SOME MINOR CHANGES PLANNED TO
DECREASE POPS A BIT SOONER BEHIND DEPARTING SYSTEM. -KT
&&
.AVIATION...
BRIEF -SHSN HAS ENDED AT KCOS AND EXPECT CLEARING SKIES FOR
THE REMAINDER OF THE NIGHT. EXPECT WINDS TO SWING AROUND FROM THE
EAST TO SOUTHEAST AT KCOS AND KPUB OVERNIGHT. THIS LIGHT UPSLOPE
COULD BE SUFFICIENT TO PRODUCE A FEW020 LAYER AT KCOS TOWARDS
12Z...BUT MOST MODELS SHOW SUFFICIENT DRY AIR ALOFT BEHIND THE
DEPARTING SYSTEM TO PREVENT A WIDESPREAD STRATUS LAYER IN SPITE OF
THE LIGHT UPSLOPE WINDS. WILL CONTINUE TO MONITOR THIS BUT WILL
NOT INTRODUCE THIS INTO TAF GIVEN ITS LOW PROBABILITY OF
OCCURENCE. OTHERWISE...MOSTLY CLEAR SKIES EXPECTED FOR TUESDAY
WITH INCREASING S-SE WINDS 10-15 KTS FOR KCOS AND KPUB. KALS WILL
SEE A BRIEF PERIOD OF GUSTY WEST WINDS EARLY IN THE PERIOD...WITH
WINDS BECOMING LIGHT AFTER 08Z UNTIL TUES AFTN WHEN SW WINDS WILL
INCREASE AT 10-15 KTS. -KT
&&
.PREV DISCUSSION... /ISSUED 617 PM MST MON JAN 16 2012/
UPDATE...
UPDATED FORECAST PACKAGE TO TAKE DOWN WINTER WEATHER HIGHLIGHTS
FOR THE SOUTHWEST MOUNTAINS. BACK EDGE OF SNOW ALONG LEADING EDGE
OF TROF AXIS WILL CONTINUE MOVING THROUGH THE CENTRAL MTS AND
ACROSS EAST CENTRAL CO OVER THE NEXT SEVERAL HOURS. HAVE INCREASED
POPS FOR NRN EL PASO COUNTY WHERE RUC13 AND LATEST RADAR TRENDS
SUGGEST AT LEAST A PERIOD OF SCATTERED SNOW SHOWERS ALONG THE NRN
EL PASO CO BORDER THROUGH 04Z. NOT EXPECTING MUCH ACCUMULATION AS
THESE SHOULD BE FAIRLY BRIEF IN NATURE. -KT
PREV DISCUSSION... /ISSUED 226 PM MST MON JAN 16 2012/
SHORT TERM...
(TONIGHT AND TUESDAY)
CURRENTLY...
PACIFIC FRONT HAS MOVED EAST OF THE I-25 CORRIDOR AND WAS LOCATED BY
RADAR AT 1 PM ALONG THE PUEBLO/OTERO AND CROWLEY COUNTY LINE. SAT
PIX AND SIMULATIONS SHOW BROAD TROUGH AT MID LEVELS WAS LOCATED OVER
THE E UTAH AND WAS PROGRESSING EAST. CLOUDINESS ASSOCIATED WITH THE
TROUGH OVER THE MTNS WAS BECOMING MORE CONVECTIVE IN NATURE AND
CLOUD TOPS WERE WARMING...ESPECIALLY OVER THE S CO.
REST OF TODAY AND THIS EVENING...
AS PAC FRONT MOVES EAST ACROSS THE E PLAINS...TEMPS WILL LIKELY RISE
FROM THEIR CURRENT VALUES. THIS PAC FRONT WILL LIKELY ADVANCE AS FAR
EAST AS W KIOWA/KLAA/KSPD LINE BEFORE CRASHING INTO THE MODIFIED
ARCTIC BOUNDARY THAT WILL DROP SOUTH/BACK DOOR INTO THE AREA ACROSS
THE REGION THIS EVENING. WITH THE STRONG WESTERLY WINDS BLOWING OVER
MOST OF THE PLAINS THIS EVENING TEMPS WILL ONLY GRADUALLY DROP...AND
WILL REMAIN ON THE MILD SIDE UNTIL THE ARCTIC FRONT MOVES THROUGH.
AS BROAD TROUGH GETS CLOSER WINDS AT MTN TOP LEVELS WILL SHIFT TO A
MORE WESTERLY AND THEN NORTHWESTERLY COMPONENT. SNOWS ACROSS THE SAN
JUANS WILL GRADUALLY DECREASE AS THIS HAPPENS AND PLAN TO LET THE
ADVISORY END AT ITS SCHEDULED TIME (6 PM). SNOW WILL CONTINUE ACROSS
THE CENTRAL MTNS INTO THE MID EVENING HOURS.
LATER TONIGHT...
MODIFIED ARCTIC BOUNDARY SHOULD ENTER KIOWA COUNTY AND NORTHERN EL
PASO COUNTY AROUND 03-04Z. WE WILL LIKELY SEE SOME INCREASE IN
CLOUDS AND CANNOT RULE OUT A BRIEF SNOW SHOWER NORTH OF US50 AS THE
BOUNDARY MOVES THROUGH. THE BOUNDARY WILL THEN CONTINUE TO DROP
SOUTH AND WILL BE THROUGH THE ENTIRE CWA BY 09Z.
WINDS OVER THE HIGHER TRRN WILL ABATE CONSIDERABLY.
TOMORROW...
IT WILL BE MOSTLY SUNNY MOST AREAS BUT IT WILL BE MUCH COLDER THAN
TODAY. HIGH TEMPS WILL LIKELY ONLY IN THE LOWER TO MID 30S ACROSS
MOST OF THE REGION. AREAS WHICH MAY BE A BIT WARMER WILL BE DOWN
NEAR KTAD WHERE DOWNSLOPE OFF THE RATON MESA MAY ALLOW TEMPS TO
APPROACH NEAR 40. OVER THE MTNS ALONG THE CONTDVD EXPECT PARTLY
CLOUDY SKIES WITH ISOLD SNOW SHOWERS...ESPECIALLY OVER THE C MTNS.
WINDS OVER THE MTNS WILL BE PICKING UP ONE AGAIN AS ANOTHER SPEED
MAX APPROACHES THE REGION. BY LATE IN THE DAY WINDS WILL BE IN THE
20 TO 40 MPH RANGE...ESPECIALLY C MTNS AND PIKES PEAK.
LONG TERM...
(TUESDAY NIGHT THROUGH MONDAY)
.CONTINUING MOUNTAIN SNOW AND BREEZY CONDITIONS...
ZONAL FLOW IS FORECAST TO PERSIST THROUGH MUCH OF THE EXTENDED
WITH SEVERAL EMBEDDED WAVES AND PERIODS OF STRONG GUSTY WINDS. THE
PATTERN WILL BE DOMINATED BY A LARGE LOW PRESSURE CENTER OVER
CENTRAL CANADA WHICH WILL PRODUCE THE ZONAL FLOW.
THE FIRST MAIN CONCERN WILL BE THE POTENTIAL FOR STRONG WINDS
TUESDAY NIGHT INTO WEDNESDAY MORNING. A SHORTWAVE TROUGH IS
FORECAST TO TRACK ACROSS WYOMING INTO THE CENTRAL PLAINS WITH A
STRONG JET STREAM MOVING OVER THE ROCKIES. MODELS INDICATING A
PERIOD...ROUGHLY FROM 03Z THROUGH AROUND 18Z WEDNESDAY FOR STRONG
WINDS. DOWNSLOPE POTENTIAL DOES NOT LOOK OVERLY GREAT WITH BRUTE
FORCE BEING THE MOST LIKELY SCENARIO. THINK THE ELEVATIONS ABOVE
11 KFT WILL LIKELY SEE GUSTS IN EXCESS OF 80 MPH WHILE THE LOWER
ELEVATIONS SEE GUSTS UP TO 50 MPH. THE STRONGEST WINDS WILL LIKELY
OCCUR ALONG THE EASTERN MOUNTAINS AND ADJACENT PLAINS WEST OF
I-25. WINDS WILL SUBSIDE DURING THE LATE AFTERNOON AS THE UPPER
LEVEL JET AND TROUGH SHIFT EAST OF THE REGION. MODELS ALL
DEVELOPING LIGHT SNOWFALL TUESDAY NIGHT AND WEDNESDAY ACROSS THE
CENTRAL MOUNTAINS BUT ACCUMULATIONS WILL ONLY BE AN INCH OR TWO.
THE NEXT FAST MOVING SHORTWAVE TROUGH IS FORECAST TO MOVE ACROSS
THE ROCKIES WEDNESDAY EVENING INTO THURSDAY. EXPECT LIGHT SNOW TO
SPREAD SOUTH ALONG THE CONTINENTAL DIVIDE INTO THE SAN JUANS
DURING THIS TIME PERIOD. AGAIN SNOW ACCUMULATIONS WILL BE MINOR
WITH ONLY AN INCH OR TWO.
A STRONGER STORM SYSTEM IS FORECAST TO MOVE INTO THE REGION FRIDAY
THROUGH SUNDAY WITH A CHANCE AT HEAVIER SNOW FOR THE CONTINENTAL
DIVIDE. EXPECT LIGHT SNOW TO PICK UP IN INTENSITY FRIDAY NIGHT AS
THE MAIN JET CORE BEGINS TO MOVE OVER THE ROCKIES. THERE APPEARS
TO BE ANOTHER SHOT AT DOWNSLOPE WINDS FRIDAY NIGHT INTO SATURDAY
MORNING BASED ON THE GFS SOUNDING AND MID LEVEL DATA. CURRENT
SOUNDINGS INDICATE A NICE MOUNTAIN TOP INVERSION WITH SOME WEAK
REVERSE SHEAR WHICH ARE ALL CONDUCIVE TO DOWNSLOPE WINDS. FOR NOW
HAVE STARTED TO INCREASE MOUNTAIN AND LEE SLOPE WINDS WHICH WILL
HAVE TO BE MONITORED.
MODELS IN SLIGHTLY BETTER AGREEMENT THIS AFTERNOON IN REGARDS TO
THE POTENTIAL FOR A STRONG SNOW STORM BEGINNING ON MONDAY. THERE
ARE MODEL DIFFERENCES IN STORM TRACK AND WIND FIELDS...BUT SOME OF
THE MODEL SOLUTIONS SUGGEST AN ACCUMULATING SNOW STORM FOR ALL OF
SOUTHERN COLORADO. THIS IS STILL A LONG WAYS OUT BUT WILL HAVE TO
BE WATCHED.
TEMPERATURES...WITH WESTERLY DOWNSLOPING WINDS...AFTERNOON HIGHS
WILL CLIMB INTO THE MID TO UPPER 50S FOR THE PLAINS. THE EXCEPTION
WILL BE THE LOWER ARKANSAS RIVER VALLEY WHERE HIGHS WILL REMAIN IN
THE 40S WITH WARMER TEMPERATURES BY THE END OF THE WEEK. 88
AVIATION...
VFR EXPECTED NEXT 24H AT ALL 3 TAF SITES...KCOS...KPUB AND KALS.
GUSTY WINDS WILL CONTINUE AT KPUB AND KCOS THIS EVENING BEFORE
DECREASING LATER THIS EVENING. PAC FRONT HAS ALREADY CROSSED THE
PLAINS TAF SITES AND THE ARCTIC FRONT WILL GRADUALLY MOVE THROUGH
THIS EVENING.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR COZ060.
&&
$$
31/44
AREA FORECAST DISCUSSION
NWS DENVER CO
910 PM MST MON JAN 16 2012
.UPDATE...SNOW IS DECREASING RATHER QUICKLY AND PRETTY MUCH ON
TRACK. ONE BAND OF SNOW STILL LINGERED FROM FORT COLLINS TO
DIA...WITH ANOTHER STRETCHING FROM THE PALMER DIVIDE THROUGH EAST
CENTRAL COLORADO. MOUNTAIN AREAS HAVE ALSO SEEN SNOW DECREASE
SHARPLY LATE THIS EVENING. OVERALL FORECAST IS ON TRACK WITH SNOW
ENDING BY/SHORTLY AFTER MIDNIGHT WITH CLEARING SKIES AND COLD
TEMPERATURES OVERNIGHT.
&&
.AVIATION...SNOW IS DECREASING SO CURRENT TRENDS INDICATE SNOW
WILL BE ALL BUT GONE AT KDEN BY 06Z. KAPA AND KBJC SHOULD SEE
FLURRIES WRAP UP IN THE NEXT HOUR. THEN CEILINGS WILL GRADUALLY
LIFT AND BREAK UP BETWEEN 06Z AND 09Z.
&&
.PREV DISCUSSION... /ISSUED 453 PM MST MON JAN 16 2012/
UPDATE...LATEST RADAR SHOWS A GOOD BAND OF SNOW ASSOCIATED WITH
UPPER TROUGH AND MID LEVEL COLD FRONT SPREADING OFF THE FOOTHILLS.
WE HAVE INCREASED SNOW CHANCES FOR DENVER METRO AREA AND NORTHEAST
ACROSS THE PLAINS DUE TO THIS FEATURE...AND SHALLOW UPSLOPE
SLOWING DISSIPATION OF THE BAND IN MEAN WESTERLY FLOW ALOFT.
AVIATION...CURRENT FORECAST IS ON TRACK WITH SHOWERS SPREADING
SOUTHEAST ACROSS THE FRONT RANGE AIRPORTS FROM NOW TIL 04Z.
VISIBILITIES COULD DROP TO 1/2 MILE AND BRIEFLY 1/4 MILE IN THE
HEAVIEST SHOWERS PER UPSTREAM OBS FROM KCYS AND FORT COLLINS
SPOTTER REPORTS...SO HAVE LOWERED THE TEMPO VSBYS IN TAFS.
PREV DISCUSSION... /ISSUED 335 PM MST MON JAN 16 2012/
SHORT TERM...WIDE BAROCLINIC ZONE ASSOCIATED WITH THE UPPER TROUGH
AND SFC COLD FRONT PASSING OVER THE MOUNTAINS AT THIS HOUR. FRONTAL
BNDRY HAS MOVED THROUGH JACKSON COUNTY AS NOTED BY A SUDDEN DROP IN
TEMPERATURE AND ABRUPT SHIFT TO NORTHWEST WINDS AT WALDEN WHERE THE
TEMPERATURE FELL 11 DEGS F IN LESS THAN AN HOUR. BANDED SLANTWISE
CONVECTION...I.E. SNOWFALL...STREAKING CROSSING THE HIGH COUNTRY
JUST AHEAD OF THE 700-500MB TROUGH AXIS. HAVE NOTICED A STEADY
INCREASE IN SNOW INTENSITY AND COVERAGE IN THE PAST COUPLE OF HOURS
WITH RUC QG VERTICAL FIELDS INDICATING WEAK TO MODERATE LARGE SCALE
ASCENT CENTERED OVER THE NRN MTNS. WHERE THIS PRECIP GOES FROM HERE
AND HOW EXTENSIVE IT WILL BE DEPENDS ON WHICH MODEL YOU LOOK AT.
BOTTOM LINE...THE NAM IS DRIER AND A BIT SLOWER WITH ITS EASTWARD
PROGRESS THAN THE GFS...ECMWF AND SREF. WHEREAS...THE GFS AND SREF
SHOW A WIDER AREA OF PRECIPITATION/SNOW FIELD ACROSS NERN COLORADO
THIS EVENING...WITH A COUPLE INCHES OF SNOW ACCUM BY MIDNIGHT
ACROSS THE NORTHEAST CORNER OF THE STATE. OVERALL SEE BANDED PRECIP
TRANSLATING SOUTHWARD ACROSS THE NERN PLAINS THIS EVENING...WITH THE
BACK EDGE OF THIS PRECIP SOUTHEAST OF THE DENVER METRO AREA BY
AROUND 05Z..AND OUT OF THE CWFA (LINCOLN COUNTY) POSSIBLY BY 08Z OR
09Z TONIGHT. EXPECTED SNOW ACCUMULATION WITHIN THE I-25 URBAN
CORRIDOR MINIMAL AT BEST...PERHAPS A HALF INCH ON GRASSY SURFACES
FROM ONE OF THE HEAVIER SNOW BANDS COMING OFF THE FOOTHILLS EARLY
THIS EVENING. AGAIN...APPEARS THE NORTHEAST CORNER IN THE BEST
POSITION TO SEE ACCUMULATING SNOWFALL THIS EVENING.
LATER TONIGHT...SHOULD SEE GUSTY NORTHWEST WINDS USHERING IN DRIER
AND COLDER AIR FROM WYOMING. CLEARING LATE WILL ALLOW FOR STRONG
RADIATIONAL COOLING CAUSING TEMPERATURES TO PLUNGE WELL BELOW ZERO
IN THE HIGH MOUNTAIN VALLEYS. MIN TEMPERATURES ALSO QUITE COLD ON
THE PLAINS WITH SINGLE DIGITS ABOVE ZERO THE NORM BY MORNING LIGHT.
COULD SEE A FEW SUBZERO READINGS IN LOW LYING AREAS SUCH AS ALONG
THE SOUTH PLATTE RIVER.
ON TUESDAY...SWIFT NORTHWEST FLOW ALOFT CONTINUES OVER THE STATE
WITH A DRIER AIRMASS UPSTREAM. ANY SNOWFALL TOMORROW WILL BE
CONFINED TO THE HIGHEST PEAKS AND WEST FACING SLOPES ALONG THE
DIVIDE. EVEN THERE SNOW INTENSITIES WILL BE WEAK. TEMPERATURES WILL
STRUGGLE TO WARM TOMORROW WITH ONGOING COLD AIR ADVECTION. SEE
LITTLE CLOUD COVER ESPECIALLY EAST OF THE MTNS WITHE FLOW
REGIME.
LONG TERM...MAIN CONCERN FOR THE UPCOMING WEEK WILL BE THE HIGH
WIND POTENTIAL IN THE MOUNTAINS...FOOTHILLS AND ADJACENT PLAINS AND
DEVELOPING SNOW IN THE MOUNTAINS BY MIDWEEK. MOST OF THE WESTERN
U.S. WILL TRANSITION TO A STRONG AND ZONAL WEST TO NORTHWEST FLOW
ALOFT THIS WEEK. IT APPEARS THE STRONGEST WINDS WILL EFFECT THE
REGION LATE TUE NIGHT THROUGH EARLY THURSDAY AM AS A STRONG
130-150KT JET CORE LIFTS OUT ACROSS WYOMING ON WEDNESDAY. THE
SURFACE PRESSURE GRADIENT WILL TIGHTEN TO 10-15 MB ACROSS THE STATE
ON WED WHILE MOUNTAIN TOP STABILITY INCREASES. CROSS SECTIONS SHOW
AMPLIFIED MOUNTAIN WAVE DEVELOPING WITH 60-80KT OF CROSS BARRIER
FLOW. STILL A LOT OF QUESTION MARKS AS THERE ARE SOME CONFLICTING
PARAMETERS. THERE IS A LOT OF VERTICAL SHEAR ESPECIALLY EARLY ON
WEDNESDAY FOR AN AMPLIFIED MOUNTAIN WAVE. SHEAR PROFILE IMPROVES A
BIT BY WED NIGHT AS THE MAIN JET IS WELL EAST OF COLORADO.
HOWEVER...THE MOUNTAIN TOP LEVEL STABILITY LOOKS QUITE IMPRESSIVE AS
STRONG MID LEVEL WARMING DEVELOPS A STRONG INVERSION IN THE
700-750MB LAYER. ALONG WITH THE TIGHTENING SURFACE GRADIENT THIS
SHOULD HELP SHIFT THE STRONGER WINDS DOWN OVER THE LOWER FOOTHILLS
AND AT THE BASE OF THE FOOTHILLS. ON THE OTHER HAND...INCREASING
MOISTURE IN THE MOUNTAINS ON WEDNESDAY MAY HELP NEGATE THE STRONGEST
WINDS AND DIMINISH THE MOUNTAIN WAVE EFFECTS. STILL ENOUGH FACTORS
TO WARRANT A HIGH WIND WATCH GIVEN THE VERY STRONG MOUNTAIN TOP FLOW
AROUND 80KTS. WILL PLAY THE WATCH TIMING IN A RATHER BROAD SCOPE FOR
NOW BUT HOPEFULLY ABLE TO NAIL DOWN TIMING AND STRENGTH BETTER IN
THE NEXT FEW DAYS.
THE NEXT QUESTION WILL BE WHAT TO DO WITH ZONES 33 AND 34 IN TERMS
OF WIND VERSUS SNOW POTENTIAL...BUT THINK THE WIND WILL BE THE
BIGGEST FACTOR HERE. MOISTURE DEPTH DOES INCREASE WEDNESDAY
AFTERNOON AND NIGHT BUT GIVEN THE INCREASING STABILITY...LAPSE RATES
DECREASE TO 2.5-4C/KM BY WED NIGHT. LOCAL SNOW MODEL GENERATES UNDER
ADVISORY AMOUNTS FOR NOW. WILL AT LEAST BUMP UP POPS TO LIKELY FOR
ZONES 31 AND 33 GIVEN THE STRONG WESTERLY OROGRAPHIC FLOW.
ACROSS LOWER ELEVATIONS IT WILL BE A DRY AND A MILD WEEK AHEAD WITH
TEMPERATURES WELL ABOVE NORMAL BY MIDWEEK WITH READINGS IN THE 50S
AND LOWER 60S THROUGH THE WEEKEND.
AVIATION...COLD FRONT ALREADY SLIPPING INTO NORTHEAST COLORADO FROM
WYOMING AS OF 22Z. AS THIS FRONT MOVES SOUTH ALONG THE FOOTHILLS
SHOULD SEE BANDS OF LIGHT SNOWFALL FORMING ALONG AND BEHIND THIS
FRONTAL BOUNDARY. AT CURRENT SPEED COULD SEE THE FRONT AND ITS
ASSOCIATED SHIFT TO GUSTY NORTH-NORTHEAST WINDS IN THE NEXT 60 TO 90
MINUTES...WITH THE HEAVIER SHOWERS BEHIND THIS BOUNDARY. MVFR
CEILINGS NOW ARE EXPECTED TO LOWER TO LOWER TO BELOW 3000 FEET AGL
AFTER 00Z/TUE WIT LOCAL LIFR CEILINGS WIT PASSING SNOW SHOWERS.
HEAVIER SHOWERS COULD ALSO PRODUCE VSBYS BELOW 2 MILES. AT THIS
TIME...IT APPEARS THAT PASSING SNOW SHOWERS WILL PRODUCE MINIMAL
SNOW ACCUMULATION IN THE DENVER ARE...PROBABLY NO MORE THAN A HALF
INCH ON GRASSY SURFACES. SHOWERS ARE EXPECTED TO MOVE OUT OF THE
DENVER AREA BY AROUND 05Z THIS EVENING...AND BY 07Z...SHOULD SEE
SKIES CLEARING WITH A SURGE OF DRIER AND COLDER AIR MOVING DOWN FROM
WYOMING. ON TUESDAY...VFR CONDITIONS WITH LIGHT WEST TO SOUTHWEST
BREEZES FOR MOST OF THE DAY UNDER MOSTLY CLEAR SKIES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE TUESDAY NIGHT THROUGH THURSDAY MORNING
FOR COZ033>036-038-039.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....ENTREKIN
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
359 AM CST TUE JAN 17 2012
.DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* IFR/LIFR CIGS EARLY THIS MORNING LIFTING TO MVFR CIGS BY
MID/LATE MORNING.
* A PERIOD OF LIGHT RAIN BEFORE DAYBREAK...THEN A PERIOD OF SNOW
FROM MID/LATE MORNING INTO MID AFTERNOON.
* NORTHWEST WINDS GUSTING TO NEAR 30 KTS FROM LATE MORNING
THROUGH LATE AFTERNOON. CMS
//DISCUSSION...UPDATED 06Z...
THE SURFACE FRONT CONTINUES DRAPED FROM WESTERN IL THROUGH CHICAGO
INTO LOWER MI. LOW PRESSURE IS EVOLVING NORTHEAST ALONG THIS
FEATURE THROUGH THE EARLY MORNING. EARLIER SHOWERS HAVE
DECREASED IN COVERAGE...HOWEVER A RE-INCREASE IN SHOWER COVERAGE
IS EXPECTED BY 09Z. SOME OF THE SHOWERS MAY PUT DOWN BRIEF
MODERATE TO HEAVY RAIN. SOME THUNDER IS POSSIBLE ACROSS THE
SOUTHERN GATES AND HAS ALREADY BEEN OBSERVED JUST NORTH OF KLAF.
SURFACE TEMPERATURES WILL REMAIN ABOVE FREEZING THROUGH 12Z WITH
HIGH CONFIDENCE...SO DO NOT EXPECT ANY FREEZING PRECIPITATION. AS
THE LOW MOVES TO THE IMMEDIATE EAST OF THE AREA BY MID
MORNING...THE ATMOSPHERIC TEMPERATURES WILL COOL SIGNIFICANTLY
FAVORING PRECIPITATION TYPE TO BE SNOW. A BRIEF MIX MAY OCCUR AT
THE LEADING EDGE OF THIS TRANSITION. WITH THE ARRIVAL OF THE SNOW
WILL ALSO COME THE ONSET OF STRONG NORTHWEST WINDS. GUSTS TO NEAR
30 KTS ARE HIGHLY LIKELY...AND THE COMBINATION OF THAT AND FALLING
SNOW WILL LIKELY LEAD TO REDUCED VISIBILITY TO 1SM OR EVEN LOWER
FOR A WHILE NEAR MIDDAY. WHILE THE CEILINGS WILL IMPROVE SLOWLY
DURING THE AFTERNOON...THE SNOW SHOULD LAST UNTIL 21Z-23Z OR SO
BEFORE ENDING. SCATTERING IS LIKELY DURING THE EVENING. MTF
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE REGARDING CIGS THROUGH DAYBREAK...MEDIUM
CONFIDENCE LATER THIS MORNING...LOW CONFIDENCE THIS AFTERNOON.
* HIGH CONFIDENCE REGARDING RAIN EARLY THIS MORNING.
* HIGH CONFIDENCE REGARDING SNOW LATER THIS MORNING INTO THIS
AFTERNOON...LOW CONFIDENCE REGARDING SPECIFICS ON TIMING...
VIS/CIGS AND AMOUNTS.
* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS/DURATION. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR. MVFR AND GUSTY WEST NORTHWEST WINDS DEVELOPING
DURING THE NIGHT.
THURSDAY...MVFR POSSIBLE. GUSTY NORTHWEST WINDS.
FRIDAY...MVFR...WITH IFR POSSIBLE. CHANCE OF SNOW.
SATURDAY...SLIGHT CHANCE OF RAIN/SNOW.
SUNDAY...SLIGHT CHANCE OF RAIN OR SNOW DURING THE NIGHT.
MTF
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM TUESDAY TO 10 PM
TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...9 AM TUESDAY TO
NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1210 AM CST TUE JAN 17 2012
.AVIATION...
PCPN SPREADING NE OVRNGT AS FRONT CONTINUES TO SLIDE THROUGH THE
CWA. EXPECTING RAIN OR FREEZING RAIN TRANSITIONING OVER TO
SNOW WITH SOME MINOR ICE ACCUMULATIONS POSSIBLE AT KCID/KDBQ/KMLI.
SNOW WILL BE OVERSPREADING TERMINALS AFT 09Z-15Z AND COULD BE
MODERATE TO BRIEFLY HEAVY AT TIMES REDUCING VSBY TO AROUND 1/2
MILE MAINLY KCID AND KDBQ TUE AM. OTRW VSBYS GENERALLY 1-5SM IN
-SN TUE AM WITH SNOW DIMINISHING LATE AM THROUGH MIDDAY. WINDS TO
BECOME NW WINDS AND INCREASE OVRNGT WITH GUSTS OF 25-30 KTS
DEVELOPING TUE AM THROUGH TUE AFTN... WITH SOME REDUCED VSBYS IN
BLOWING/DRIFTING SNOW POSSIBLE. OVERALL CONDITIONS DETERIORATING
NEXT 6-12 HRS TO MVFR/IFR WITH POTENTIAL FOR LIFR CONDITIONS AT
KCID AND KDBQ FOR A TIME TUE AM. STRONG SUBSIDENCE IN WAKE OF
UPPER LEVEL DISTURBANCE TO BRING CLEARING BY MID AFTN THROUGH
EARLY EVE WITH VFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 1004 PM CST MON JAN 16 2012/
UPDATE...
SNOW COULD MAKE FOR MESSY COMMUTE TUE AM OVER NORTHEAST IA INTO NW
IL.
PCPN BLOSSOMING OVER KS/MO AS SHORTWAVE LIFTS E/NE ALONG FRONTAL
ZONE. HEAVIEST PCPN TO STAY TO OUR SOUTH BUT SOME LIGHT PCPN
TO SPREAD E/NE ALONG ELEVATED 925-850 FRONTAL ZONE OVER THE
SOUTHEAST CWA. TEMPS WARM ENOUGH FOR ALL LIQUID AND SFC TEMPS
ABOVE FREEZING FOR MOSTLY RAIN. ADDITIONAL LIFT FROM SHORTWAVE
SHIFTING INTO CENTRAL PLAINS SHOULD BRING SNOW ACROSS THE
CWA LATER TNGT AND TUE AM. MODELS SHOWING SOME PRETTY STRONG
OMEGAS IN DENDRITIC GROWTH ZONE AND SUFFICIENT FORCING ALBEIT
FOR SHORT DURATION BUT SUFFICIENT FOR POTENTIAL SWATH OF 1-3
INCHES WITH FAVORED AXIS ROUGHLY NORTH OF KSQI-KMLI-KIOW LINE
PER WARM ADVECTION WING AND TRACK OF H85 LOW. CANT RULE OUT EVEN
SOME LOCALIZED AMOUNTS NEAR 4 INCHES IF MODELS VERIFY. SNOW
COULD HAVE AN IMPACT ON MORNING COMMUTE AS LOOKS TO BE PRIME-TIME
FOR FORCING. HAVE NUDGED UP SNOW AMOUNTS NORTH OF THE ABOVE
MENTIONED AXIS. WITH WEAK SFC LOW NOT MOVING MUCH FROM CENTRAL
IL TEMPS AND ONSET OF STRONG COLD ADVECTION DELAYED AND SO HAVE
REDUCED SNOW AND FREEZING PCPN MENTION SOUTHEAST... AND TWEAKED
UP MINS.
PREV DISCUSSION... /ISSUED 328 PM CST MON JAN 16 2012/
SYNOPSIS...
A COLD FRONT EXTENDED FROM NORTHERN LK MI SOUTHWEST THROUGH EASTERN
IOWA TO LOW PRESSURE OVER NORTHWEST MO LATE THIS AFTERNOON. SO FAR
NOT PRECIPITATION WAS OCCURRING IN THE VICINITY OF FRONT OR SURFACE
IN OR NEAR THE MID MISSISSIPPI VALLEY. THERE WAS STRONG THERMAL
GRADIENT RANGING FROM THE MID AND UPPER 60S OVER THE NORTHEAST
QUARTER OF MO TO THE MID 30S OVER NORTHEAST IOWA. LOW LEVEL
MOISTURE WAS STREAMING NORTH AHEAD OF THE LOW/FRONT WITH
WIDESPREAD MID AND UPPER 40 DEWPOINTS OVER MUCH OF NORTHEAST MO
INTO WEST CENTRAL IL. THE MIDWEST FRONT WAS SETUP AHEAD OF A 500MB
S/W TROF THAT WAS MOVING ACROSS THE CENTRAL/NORTHERN ROCKIES AT
18Z PER RUC PROGS AND WATER VAPOR IMAGERY.
SHORT TERM...TONIGHT AND TUESDAY...
A CHALLENGING FORECAST FOR THE OVER NIGHT HOURS WITH THE STRONG
COLD FRONT OVER THE AREA THIS EVENING DROPPING SOUTHEAST THROUGH
THE CWFA BY LATE EVENING. THEN SOME MID-LEVEL ENERGY MOVING
THROUGH LATE TONIGHT AFTER THE LOW LEVEL COLD AIR IS IN PLACE.
TUESDAY LOOKS LIKE A RAW WINDY DAY WITH STRONG CAA AND LINGER
FLURRIES OR LIGHT SNOW.
SO FAR WITH THIS SYSTEM PRECIPITATION HAS BEEN NON
EXISTENT...HOWEVER THAT APPEARS TO BE CHANGING AS WE GO INTO THE
OVERNIGHT HOURS. MODEL SOUNDINGS CONTINUE TO SHOW THE LOW LEVELS
SATURATING THIS EVENING WHICH SHOULD OCCUR AS THE COLD LOW LEVEL
AIR MOVES IN BEHIND THE FRONT THIS EVENING. SOME FORCING WILL BE
PRESENT IN THE LOW LEVELS IN THE FORM OF FGEN AT THE SAME TIME
MID/UPPER LEVEL RH WILL BE INCREASING AND COULD PROVIDE A FEEDER
MECHANISM FOR THE LOW CLOUDS...SO WENT WITH LOW POPS FOR LIGHT
PRECIPITATION THIS EVENING AS OPPOSED TO DRIZZLE. IF
PRECIPITATION OCCURS BEFORE MIDNIGHT THEN THE THERMAL PROFILES
WOULD FAVOR RAIN OVER THE SOUTHEAST HALF OF THE CWFA WITH A MIX OF
FZRA/SN OVER THE NORTHWEST HALF. BETTER FORCING WILL MOVE OVER THE
AREA AFTER MIDNIGHT WITH MID/UPPER FGEN INCREASING AHEAD OF VORT
MAX MOVING OUT OF THE WESTERN TROF. THE FGEN WILL BE CO-LOCATED
WITH A POCKET OF STEEPER MID LEVEL LAPSE RATES WHICH SUPPORTS A
NARROW BAND OF ENHANCED PRECIPITATION MAINLY FROM THE SOUTHWEST
CWA INTO NW IL. THERE MAY BE SOME FREEZING RAIN MIXED WITH THE
PRECIPITATION JUST AFTER MIDNIGHT BUT THE COLD AIR SHOULD DEEPEN
ENOUGH BY 09Z FOR ALL SNOW OVER THE CWFA. THE SNOW WILL LINGER
INTO THE MORNING AND END DURING THE AFTERNOON IN THE SOUTHWEST
WITH LINGERING FLURRIES IN THE NORTHEAST. BY TUESDAY AFTERNOON
SNOWFALL AMOUNTS ARE EXPECTED TO BE IN THE 1 TO 2 INCH RANGE OVER
THE NORTHWEST HALF WITH LESS THAN AN INCH IN THE SOUTHEAST HALF OF
THE CWFA. NORTHWEST WINDS GUSTING TO 25 TO 30 MPH TUESDAY MAY
CAUSE SOME BLOWING AND DRIFTING. OVERNIGHT TEMPERATURES SHOULD
FALL INTO THE TEENS NORTHWEST TO MID 20S SOUTHEAST. ONGOING STRONG
LOW LEVEL CAA AND CLOUDS WILL ALLOW TEMPERATURES TO CONTINUE
FALLING DURING THE DAY AND SHOULD BE IN THE TEENS BY MID AFTERNOON
OVER ALL BUT THE SOUTHWEST CORNER WHERE LOW TO MID 20S ARE
ANTICIPATED. ..DLF..
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...
TUESDAY NIGHT AND WEDNESDAY...LOOKING AT THE LATEST AVAILABLE
12Z RUN MODEL GUIDANCE...CLEARING AND COLD CONDITIONS STILL ON
TRACK FOR TUE NIGHT IN SUBSIDENCE WAKE OF THE EXITING GRT LKS SYSTEM
AND ARRIVAL OF LLVL RIDGE LOBE. SOME LOWS BELOW ZERO POSSIBLE IN
AREAS NORTH OF I80/FAVORED VALLEY REGIONS...OTHERWISE OTHER AREAS
TO BE IN THE SINGLE DIGITS ABOVE ZERO. THESE LATEST 12Z RUNS STILL
SUGGEST AN UPPER LEVEL WAVE WILL PROPAGATE OUT OF THE ACTIVE
PACIFIC NW REGION AND PASS ACRS PORTIONS OF MN AND WI CLIPPER-
STYLE IN FRESHLY ESTABLISHED BROAD NORTH-WESTERLIES...TO USHER YET
ANOTHER FRONT INTO THE CWA BY LATE WED NIGHT AND INTO THU MORNING.
STILL APPEARS A POSSIBILITY OF OR EVEN POST-FRONTAL LIGHT SNOW IN
MUCH OF THE CWA WED NIGHT AND INTO THU MORNING. FOR NOW...WILL ADD
A SLIGHT CHC FOR MEASURABLE SNOW IN THE FAR NORTHEASTERN CWA BUT
ADD FLURRIES FOR MUCH OF THE REMAINDER OF THE FCST AREA. THE 12Z
GFS REMAINS THE QUICKEST SOLUTION IN HANDLING THE FROPA MAKING IT
TO THE WESTERN OH RVR VALLEY BY 12Z THU AND POST-FRONTAL COLD RUSH
WELL IMPLANTED ACRS THE LOCAL AREA...BUT OTHER MODELS INCLUDING
THE ECMWF HAVE SPED UP THIS PROCESS AS WELL. THUS IT APPEARS A
COLD BLUSTERY LATE WED NIGHT-THU MORNING COULD BE IN STORE WITH
LOW SINGLE DIGIT LOWS BY DAWN THU AND WIND CHILLS IN THE DOUBLE
DIGITS BELOW ZERO.
THURSDAY THROUGH FRIDAY...ONGOING LIGHT SNOW AND FLURRIES TO
START THE PERIOD OFF THU MORNING...BUT AGAIN NORTHWEST WINDS IN
STOUT CAA/INCOMING SFC RIDGE PRESSURE GRADIENT COULD BE GUSTING OVER
30 MPH AND PRODUCING DOUBLE DIGIT BELOW ZERO WIND CHILL VALUES
THROUGH AT LEAST MID MORNING. PASSING 1025+ MB COLD HIGH PRESSURE
SYSTEM WITH ORIGINS FROM WESTERN CANADA WILL THEN SCOUR THINGS OUT
FOR THE REST OF THE DAY AND INTO THU EVENING BEFORE HIGH CLOUDS
INCREASE AGAIN FROM THE WEST AHEAD OF THE NEXT POTENTIAL SYSTEM. LLVL
BAROCLINICITY STILL TO GET ALIGNED PARALLEL UNDER THE DEVELOPING MEAN
FLOW NORTH-WESTERLIES ACRS OR NEAR THE DVN CWA ON THU AND TIGHTENING
UP AS THE PERIOD PROGRESSES. LATEST MEDIUM RANGE MODEL RUNS CONTINUE
TO PICK UP ON A MORE SUBSTANTIAL TYPE CLIPPER-LIKE WAVE PROPAGATING
DOWN IN THIS FLOW ALONG THE LLVL THERMAL RIBBON TOWARD WEEKS END.
THIS SYSTEM WILL LOOK TO UTILIZE SOME GULF MOISTURE FEED FROM
THE SOUTH...BUT THE MODELS CONTINUE TO VARY FROM RUN-TO-RUN ON HOW
FAR NORTH OR SOUTH THIS FEATURE WILL TRACK AS WELL AS INCOMING SPEED.
THEY STILL SUGGEST A WAVE STRONG ENOUGH TO PRODUCE 1-3 OR EVEN 2-4
INCHES OF SNOW SOMEWHERE IN THE REGION...WITH THE LATEST 12Z RUN
GFS NOW MAKING A DIRECT HIT ON THE CWA FROM LATE THU NIGHT INTO
FRI MORNING WITH WIDESPREAD 2-4 INCHES BY 18Z FRI BEFORE THE
SYSTEM SHUTTLES OFF TO THE EAST. THE NEW 12Z ECMWF IS NOW SLOWER
AND FURTHER NORTH...SUGGESTING A DRY THU NIGHT AND THEN ACCUMULATING
SNOWS OF 2-5+ INCHES MAINLY ACRS MN/NE IA AND SOUTH HALF OF WI ON
FRI. THE EURO DOES TRY TO DO SOME PHASING/DIGGING RIGHT OVER AND
JUST SOUTHEAST OF THE DVN CWA LATER FRI WHICH MAY THEN WRAP SOME
ACCUMULATING SNOWS BACK ON THE NORTHEASTERN AND NORTHERN CWA FRI
AFTERNOON AND INTO THE EVENING WITH ACCUMULATIONS POSSIBLE.
INTERESTING THAT THE LATEST RUNS ARE LESS BULLISH ON THE EXTENT OF
WARM DRAW FROM THE SOUTH SO FOR NOW WILL JUST ADVERTISE ALL SNOW
ON FRI INSTEAD OF A MIX IN THE SOUTH. BUT THERE IS TIME FOR LATER
RUNS TO AGAIN CHANGE ON THAT ASPECT. WILL KEEP MODERATE CHC POPS
GOING ALONG WITH THE SNOW WORDING ON FRI FOR NOW.
SATURDAY THROUGH MONDAY...LONG RANGE SIGNALS/ENSEMBLES AND TRENDS ON
PROJECTED H5 MB GEOPOTENTIAL HEIGHT FIELDS SUGGEST L/W TROF ENERGY TO
DIG ACRS THE WESTERN COAST...WITH RESULTANT FLATTENING FLOW TO MID
CONUS RIDGING TAKING PLACE BEHIND THE EXITING FRI SYSTEM OVER THE
WEEKEND. STRONG THERMAL MODERATION SIGNALS ARE THERE WITH A TAP INTO
ANOTHER ROUND OF BUILDING WARM POOL ACRS THE SOUTHERN PLAINS BY
SUNDAY...AS OPPOSED TO SAT WHICH NOW DOES NOT APPEAR WILL BE AS
MILD AFTER A COLD START/FRI NIGHT AND SOME DELAY IN RETURN FLOW.
THERMAL PROFILES ARE ALMOST THERE TO SUPPORT HIGHS NEAR 50 BY NEXT
SUNDAY WITH ENOUGH MIXING AND INSOLATION...BUT MUCH WILL DEPEND ON
ANY NEW SNOW COVER FROM THE FRI SYSTEM AND MOISTURE RETURN GOING INTO
CLOUD PRODUCTION LIMITING THE WARM UP POTENTIAL WHICH IS COMMON IN
THIS TYPE OF WAA SCENARIO. WILL TAKE THE PRECIP OUT FOR NEXT SUNDAY
UNDER THE EXPECTED THERMAL RIDGE...BUT NOT GO QUITE AS WARM AS THE
POTENTIAL IS FOR NOW....UPPER 30S IN THE FAR NORTH TO THE MID/UPPER
40S ALONG AND SOUTH OF I80. MODEL DISCREPANCIES AND PHASING ISSUES
APLENTY IN HANDLING EVENTUAL IN-LAND PROPAGATING WAVE ENERGY OUT OF
THE WESTERN TROFFINESS FOR LATE IN THE WEEKEND AND INTO EARLY NEXT
WEEK. BUT LOOKING AT LONG RANGE UPPER JET PLACEMENT AND AIRMASS
STEERING MECHANISMS THE ABOVE NORMAL THERMAL REGIME STILL LOOKS LIKE
IT WILL BE WELL IN PLACE BY THE TIME THESE WAVE SYSTEM AND ASSOCIATED
SFC FEATURES TRY TO PUSH ACRS THE MIDWEST. THUS MAINLY A RAIN THREAT
FOR THE MONDAY PERIOD...BUT CONFIDENCE ON THIS TIMING LOW. THE ECMWF
ACTUALLY PUSHES A FRONT THROUGH THE CWA SUNDAY NIGHT WITH A RAIN
THREAT...AND THEN IS DRY AND COOLER FOR MONDAY AS THE NEXT LARGE
SYSTEM ORGANIZES UPSTREAM AND LOOMS OVER THE GRT BSN/SW PLAINS WITH
THOUGHTS OF IMPACTING THE MIDWEST BY MID NEXT WEEK. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1004 PM CST MON JAN 16 2012
.UPDATE...
SNOW COULD MAKE FOR MESSY COMMUTE TUE AM OVER NORTHEAST IA INTO NW
IL.
PCPN BLOSSOMING OVER KS/MO AS SHORTWAVE LIFTS E/NE ALONG FRONTAL
ZONE. HEAVIEST PCPN TO STAY TO OUR SOUTH BUT SOME LIGHT PCPN
TO SPREAD E/NE ALONG ELEVATED 925-850 FRONTAL ZONE OVER THE
SOUTHEAST CWA. TEMPS WARM ENOUGH FOR ALL LIQUID AND SFC TEMPS
ABOVE FREEZING FOR MOSTLY RAIN. ADDITIONAL LIFT FROM SHORTWAVE
SHIFTING INTO CENTRAL PLAINS SHOULD BRING SNOW ACROSS THE
CWA LATER TNGT AND TUE AM. MODELS SHOWING SOME PRETTY STRONG
OMEGAS IN DENDRITIC GROWTH ZONE AND SUFFICIENT FORCING ALBEIT
FOR SHORT DURATION BUT SUFFICIENT FOR POTENTIAL SWATH OF 1-3
INCHES WITH FAVORED AXIS ROUGHLY NORTH OF KSQI-KMLI-KIOW LINE
PER WARM ADVECTION WING AND TRACK OF H85 LOW. CANT RULE OUT EVEN
SOME LOCALIZED AMOUNTS NEAR 4 INCHES IF MODELS VERIFY. SNOW
COULD HAVE AN IMPACT ON MORNING COMMUTE AS LOOKS TO BE PRIME-TIME
FOR FORCING. HAVE NUDGED UP SNOW AMOUNTS NORTH OF THE ABOVE
MENTIONED AXIS. WITH WEAK SFC LOW NOT MOVING MUCH FROM CENTRAL
IL TEMPS AND ONSET OF STRONG COLD ADVECTION DELAYED AND SO HAVE
REDUCED SNOW AND FREEZING PCPN MENTION SOUTHEAST... AND TWEAKED
UP MINS.
&&
.PREV DISCUSSION... /ISSUED 603 PM CST MON JAN 16 2012/
AVIATION...
CONDITIONS EXPECTED TO DETERIORATE LATER THIS EVE AND OVRNGT AS
COLD FRONT MOVES THROUGH WITH VFR CONDITIONS GIVING WAY TO
MVFR AND IFR CONDITIONS IN POSSIBLY A WINTRY MIX OF VERY LIGHT
RAIN OR DRIZZLE OR FREEZING DRIZZLE AND SNOW. PCPN EXPECTED TO GO
OVER TO ALL SNOW LATE TNGT AND PERSIST THROUGH TUE AM AS AN
UPPER LEVEL DISTURBANCE PASSES... WITH SOME ACCUMULATIONS
LIKELY AT KDBQ/KCID/KMLI. NW WINDS WILL BE INCREASING OVRNGT
WITH GUSTS OF 25-30 KTS DEVELOPING MID-LATE TUE AM THROUGH TUE
AFTN... WITH SOME REDUCED VSBYS IN BLOWING/DRIFTING SNOW POSSIBLE
MAINLY AT KDBQ. STRONG SUBSIDENCE IN WAKE OF DEPARTING DISTURBANCE
TUE AFTN TO LIKELY BRING RAPID CLEARING BY MID TO LATE TUE AFTN.
PREV DISCUSSION... /ISSUED 328 PM CST MON JAN 16 2012/
SYNOPSIS...
A COLD FRONT EXTENDED FROM NORTHERN LK MI SOUTHWEST THROUGH EASTERN
IOWA TO LOW PRESSURE OVER NORTHWEST MO LATE THIS AFTERNOON. SO FAR
NOT PRECIPITATION WAS OCCURRING IN THE VICINITY OF FRONT OR SURFACE
IN OR NEAR THE MID MISSISSIPPI VALLEY. THERE WAS STRONG THERMAL
GRADIENT RANGING FROM THE MID AND UPPER 60S OVER THE NORTHEAST
QUARTER OF MO TO THE MID 30S OVER NORTHEAST IOWA. LOW LEVEL
MOISTURE WAS STREAMING NORTH AHEAD OF THE LOW/FRONT WITH
WIDESPREAD MID AND UPPER 40 DEWPOINTS OVER MUCH OF NORTHEAST MO
INTO WEST CENTRAL IL. THE MIDWEST FRONT WAS SETUP AHEAD OF A 500MB
S/W TROF THAT WAS MOVING ACROSS THE CENTRAL/NORTHERN ROCKIES AT
18Z PER RUC PROGS AND WATER VAPOR IMAGERY.
SHORT TERM...TONIGHT AND TUESDAY...
A CHALLENGING FORECAST FOR THE OVER NIGHT HOURS WITH THE STRONG
COLD FRONT OVER THE AREA THIS EVENING DROPPING SOUTHEAST THROUGH
THE CWFA BY LATE EVENING. THEN SOME MID-LEVEL ENERGY MOVING
THROUGH LATE TONIGHT AFTER THE LOW LEVEL COLD AIR IS IN PLACE.
TUESDAY LOOKS LIKE A RAW WINDY DAY WITH STRONG CAA AND LINGER
FLURRIES OR LIGHT SNOW.
SO FAR WITH THIS SYSTEM PRECIPITATION HAS BEEN NON
EXISTENT...HOWEVER THAT APPEARS TO BE CHANGING AS WE GO INTO THE
OVERNIGHT HOURS. MODEL SOUNDINGS CONTINUE TO SHOW THE LOW LEVELS
SATURATING THIS EVENING WHICH SHOULD OCCUR AS THE COLD LOW LEVEL
AIR MOVES IN BEHIND THE FRONT THIS EVENING. SOME FORCING WILL BE
PRESENT IN THE LOW LEVELS IN THE FORM OF FGEN AT THE SAME TIME
MID/UPPER LEVEL RH WILL BE INCREASING AND COULD PROVIDE A FEEDER
MECHANISM FOR THE LOW CLOUDS...SO WENT WITH LOW POPS FOR LIGHT
PRECIPITATION THIS EVENING AS OPPOSED TO DRIZZLE. IF
PRECIPITATION OCCURS BEFORE MIDNIGHT THEN THE THERMAL PROFILES
WOULD FAVOR RAIN OVER THE SOUTHEAST HALF OF THE CWFA WITH A MIX OF
FZRA/SN OVER THE NORTHWEST HALF. BETTER FORCING WILL MOVE OVER THE
AREA AFTER MIDNIGHT WITH MID/UPPER FGEN INCREASING AHEAD OF VORT
MAX MOVING OUT OF THE WESTERN TROF. THE FGEN WILL BE CO-LOCATED
WITH A POCKET OF STEEPER MID LEVEL LAPSE RATES WHICH SUPPORTS A
NARROW BAND OF ENHANCED PRECIPITATION MAINLY FROM THE SOUTHWEST
CWA INTO NW IL. THERE MAY BE SOME FREEZING RAIN MIXED WITH THE
PRECIPITATION JUST AFTER MIDNIGHT BUT THE COLD AIR SHOULD DEEPEN
ENOUGH BY 09Z FOR ALL SNOW OVER THE CWFA. THE SNOW WILL LINGER
INTO THE MORNING AND END DURING THE AFTERNOON IN THE SOUTHWEST
WITH LINGERING FLURRIES IN THE NORTHEAST. BY TUESDAY AFTERNOON
SNOWFALL AMOUNTS ARE EXPECTED TO BE IN THE 1 TO 2 INCH RANGE OVER
THE NORTHWEST HALF WITH LESS THAN AN INCH IN THE SOUTHEAST HALF OF
THE CWFA. NORTHWEST WINDS GUSTING TO 25 TO 30 MPH TUESDAY MAY
CAUSE SOME BLOWING AND DRIFTING. OVERNIGHT TEMPERATURES SHOULD
FALL INTO THE TEENS NORTHWEST TO MID 20S SOUTHEAST. ONGOING STRONG
LOW LEVEL CAA AND CLOUDS WILL ALLOW TEMPERATURES TO CONTINUE
FALLING DURING THE DAY AND SHOULD BE IN THE TEENS BY MID AFTERNOON
OVER ALL BUT THE SOUTHWEST CORNER WHERE LOW TO MID 20S ARE
ANTICIPATED. ..DLF..
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...
TUESDAY NIGHT AND WEDNESDAY...LOOKING AT THE LATEST AVAILABLE
12Z RUN MODEL GUIDANCE...CLEARING AND COLD CONDITIONS STILL ON
TRACK FOR TUE NIGHT IN SUBSIDENCE WAKE OF THE EXITING GRT LKS SYSTEM
AND ARRIVAL OF LLVL RIDGE LOBE. SOME LOWS BELOW ZERO POSSIBLE IN
AREAS NORTH OF I80/FAVORED VALLEY REGIONS...OTHERWISE OTHER AREAS
TO BE IN THE SINGLE DIGITS ABOVE ZERO. THESE LATEST 12Z RUNS STILL
SUGGEST AN UPPER LEVEL WAVE WILL PROPAGATE OUT OF THE ACTIVE
PACIFIC NW REGION AND PASS ACRS PORTIONS OF MN AND WI CLIPPER-
STYLE IN FRESHLY ESTABLISHED BROAD NORTH-WESTERLIES...TO USHER YET
ANOTHER FRONT INTO THE CWA BY LATE WED NIGHT AND INTO THU MORNING.
STILL APPEARS A POSSIBILITY OF OR EVEN POST-FRONTAL LIGHT SNOW IN
MUCH OF THE CWA WED NIGHT AND INTO THU MORNING. FOR NOW...WILL ADD
A SLIGHT CHC FOR MEASURABLE SNOW IN THE FAR NORTHEASTERN CWA BUT
ADD FLURRIES FOR MUCH OF THE REMAINDER OF THE FCST AREA. THE 12Z
GFS REMAINS THE QUICKEST SOLUTION IN HANDLING THE FROPA MAKING IT
TO THE WESTERN OH RVR VALLEY BY 12Z THU AND POST-FRONTAL COLD RUSH
WELL IMPLANTED ACRS THE LOCAL AREA...BUT OTHER MODELS INCLUDING
THE ECMWF HAVE SPED UP THIS PROCESS AS WELL. THUS IT APPEARS A
COLD BLUSTERY LATE WED NIGHT-THU MORNING COULD BE IN STORE WITH
LOW SINGLE DIGIT LOWS BY DAWN THU AND WIND CHILLS IN THE DOUBLE
DIGITS BELOW ZERO.
THURSDAY THROUGH FRIDAY...ONGOING LIGHT SNOW AND FLURRIES TO
START THE PERIOD OFF THU MORNING...BUT AGAIN NORTHWEST WINDS IN
STOUT CAA/INCOMING SFC RIDGE PRESSURE GRADIENT COULD BE GUSTING OVER
30 MPH AND PRODUCING DOUBLE DIGIT BELOW ZERO WIND CHILL VALUES
THROUGH AT LEAST MID MORNING. PASSING 1025+ MB COLD HIGH PRESSURE
SYSTEM WITH ORIGINS FROM WESTERN CANADA WILL THEN SCOUR THINGS OUT
FOR THE REST OF THE DAY AND INTO THU EVENING BEFORE HIGH CLOUDS
INCREASE AGAIN FROM THE WEST AHEAD OF THE NEXT POTENTIAL SYSTEM. LLVL
BAROCLINICITY STILL TO GET ALIGNED PARALLEL UNDER THE DEVELOPING MEAN
FLOW NORTH-WESTERLIES ACRS OR NEAR THE DVN CWA ON THU AND TIGHTENING
UP AS THE PERIOD PROGRESSES. LATEST MEDIUM RANGE MODEL RUNS CONTINUE
TO PICK UP ON A MORE SUBSTANTIAL TYPE CLIPPER-LIKE WAVE PROPAGATING
DOWN IN THIS FLOW ALONG THE LLVL THERMAL RIBBON TOWARD WEEKS END.
THIS SYSTEM WILL LOOK TO UTILIZE SOME GULF MOISTURE FEED FROM
THE SOUTH...BUT THE MODELS CONTINUE TO VARY FROM RUN-TO-RUN ON HOW
FAR NORTH OR SOUTH THIS FEATURE WILL TRACK AS WELL AS INCOMING SPEED.
THEY STILL SUGGEST A WAVE STRONG ENOUGH TO PRODUCE 1-3 OR EVEN 2-4
INCHES OF SNOW SOMEWHERE IN THE REGION...WITH THE LATEST 12Z RUN
GFS NOW MAKING A DIRECT HIT ON THE CWA FROM LATE THU NIGHT INTO
FRI MORNING WITH WIDESPREAD 2-4 INCHES BY 18Z FRI BEFORE THE
SYSTEM SHUTTLES OFF TO THE EAST. THE NEW 12Z ECMWF IS NOW SLOWER
AND FURTHER NORTH...SUGGESTING A DRY THU NIGHT AND THEN ACCUMULATING
SNOWS OF 2-5+ INCHES MAINLY ACRS MN/NE IA AND SOUTH HALF OF WI ON
FRI. THE EURO DOES TRY TO DO SOME PHASING/DIGGING RIGHT OVER AND
JUST SOUTHEAST OF THE DVN CWA LATER FRI WHICH MAY THEN WRAP SOME
ACCUMULATING SNOWS BACK ON THE NORTHEASTERN AND NORTHERN CWA FRI
AFTERNOON AND INTO THE EVENING WITH ACCUMULATIONS POSSIBLE.
INTERESTING THAT THE LATEST RUNS ARE LESS BULLISH ON THE EXTENT OF
WARM DRAW FROM THE SOUTH SO FOR NOW WILL JUST ADVERTISE ALL SNOW
ON FRI INSTEAD OF A MIX IN THE SOUTH. BUT THERE IS TIME FOR LATER
RUNS TO AGAIN CHANGE ON THAT ASPECT. WILL KEEP MODERATE CHC POPS
GOING ALONG WITH THE SNOW WORDING ON FRI FOR NOW.
SATURDAY THROUGH MONDAY...LONG RANGE SIGNALS/ENSEMBLES AND TRENDS ON
PROJECTED H5 MB GEOPOTENTIAL HEIGHT FIELDS SUGGEST L/W TROF ENERGY TO
DIG ACRS THE WESTERN COAST...WITH RESULTANT FLATTENING FLOW TO MID
CONUS RIDGING TAKING PLACE BEHIND THE EXITING FRI SYSTEM OVER THE
WEEKEND. STRONG THERMAL MODERATION SIGNALS ARE THERE WITH A TAP INTO
ANOTHER ROUND OF BUILDING WARM POOL ACRS THE SOUTHERN PLAINS BY
SUNDAY...AS OPPOSED TO SAT WHICH NOW DOES NOT APPEAR WILL BE AS
MILD AFTER A COLD START/FRI NIGHT AND SOME DELAY IN RETURN FLOW.
THERMAL PROFILES ARE ALMOST THERE TO SUPPORT HIGHS NEAR 50 BY NEXT
SUNDAY WITH ENOUGH MIXING AND INSOLATION...BUT MUCH WILL DEPEND ON
ANY NEW SNOW COVER FROM THE FRI SYSTEM AND MOISTURE RETURN GOING INTO
CLOUD PRODUCTION LIMITING THE WARM UP POTENTIAL WHICH IS COMMON IN
THIS TYPE OF WAA SCENARIO. WILL TAKE THE PRECIP OUT FOR NEXT SUNDAY
UNDER THE EXPECTED THERMAL RIDGE...BUT NOT GO QUITE AS WARM AS THE
POTENTIAL IS FOR NOW....UPPER 30S IN THE FAR NORTH TO THE MID/UPPER
40S ALONG AND SOUTH OF I80. MODEL DISCREPANCIES AND PHASING ISSUES
APLENTY IN HANDLING EVENTUAL IN-LAND PROPAGATING WAVE ENERGY OUT OF
THE WESTERN TROFFINESS FOR LATE IN THE WEEKEND AND INTO EARLY NEXT
WEEK. BUT LOOKING AT LONG RANGE UPPER JET PLACEMENT AND AIRMASS
STEERING MECHANISMS THE ABOVE NORMAL THERMAL REGIME STILL LOOKS LIKE
IT WILL BE WELL IN PLACE BY THE TIME THESE WAVE SYSTEM AND ASSOCIATED
SFC FEATURES TRY TO PUSH ACRS THE MIDWEST. THUS MAINLY A RAIN THREAT
FOR THE MONDAY PERIOD...BUT CONFIDENCE ON THIS TIMING LOW. THE ECMWF
ACTUALLY PUSHES A FRONT THROUGH THE CWA SUNDAY NIGHT WITH A RAIN
THREAT...AND THEN IS DRY AND COOLER FOR MONDAY AS THE NEXT LARGE
SYSTEM ORGANIZES UPSTREAM AND LOOMS OVER THE GRT BSN/SW PLAINS WITH
THOUGHTS OF IMPACTING THE MIDWEST BY MID NEXT WEEK. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1120 PM CST MON JAN 16 2012
.AVIATION...
FOR THE 06Z TAF ISSUANCE...
SURFACE OBSERVATIONS ACROSS PORTIONS OF NORTHWEST KANSAS AT 02Z
INDICATING LIGHT SNOW WAS OCCURRING NEAR THE MID LEVEL BAROCLINIC
ZONE THAT WAS LOCATED AHEAD OF AN UPPER LEVEL TROUGH. AS OF 04Z
BASED ON THE LATEST WATER VAPOR LOOP THE NAM AND RUC SEEMED HAVE
A DECENT HANDLE WITH THIS UPPER LEVEL TROUGH AS IT CURRENTLY MOVES
EASTWARD TOWARDS WESTERN NEBRASKA AND WESTERN KANSAS. BASED ON THE
CURRENT TIMING AND TRACK OF THIS UPPER LEVEL TROUGH FROM THE
RUC/NAM ALONG WITH THE FORECAST LOCATION OF THE MID LEVEL
BAROCLINIC ZONE AND MOISTURE THERE WILL BE A CHANCE FOR SOME
LIGHT SNOW/FLURRIES AGAIN LATER THIS MORNING IN THE HAYS AREA BEFORE
12Z. FURTHER SOUTH LIFT APPEARS WEAKER. WINDS HOWEVER ARE EXPECTED
STAY UP BASED BOUNDARY LAYER WINDS AND 3HR SURFACE PRESSURE
CHANGE. BASED ON BUFR SOUNDINGS THE BASES THE CLOUDS OVERNIGHT
NIGHT ARE EXPECTED TO BRIEFLY LOWER TO AROUND 1500FT.
SUBSIDENCE WILL DEVELOP BEHIND AN UPPER LEVEL TROUGH AS IT MOVES
EAST OF THE AREA EARLY TUESDAY. IN ADDITION AN AREA OF HIGH
PRESSURE WILL BEGIN TO BUILD INTO THE AREA FROM THE NORTHWEST.
WINDS WILL SUBSIDE DURING THE DAY ON TUESDAY AS SKIES CLEAR. -RB
&&
PREV DISCUSSION... /ISSUED 400 PM CST MON JAN 16 2012/
SYNOPSIS...
A SHORTWAVE TROUGH WAS PROGRESSING ACROSS THE INTERMOUNTAIN WEST
THIS AFTERNOON. AHEAD OF THIS SYSTEM, A COLD FRONT PROGRESSED
THROUGH WESTERN KANSAS AND THEN STALLED EARLY THIS AFTERNOON
ALONG THE OKLAHOMA BORDER. THERE WAS A PRONOUNCED LOW-LEVEL THERMAL
GRADIENT ALONG THIS FRONT WITH TEMPERATURES NEAR 70F TO THE SOUTH
AND 30S/40S TO THE NORTH. TEMPERATURES WELL NORTH OF THE FRONT
OVER NORTHERN NEBRASKA AND SOUTH DAKOTA WERE IN THE TEENS. A
DRYLINE STRETCHED FROM NORTHWESTERN OKLAHOMA INTO SOUTHWESTERN
TEXAS. GULF MOISTURE WAS PROGRESSING INTO WESTERN AND NORTHERN
OKLAHOMA WITH DEWPOINTS IN THE 45 TO 55F RANGE.
DISCUSSION...
DAYS 1-2...
AS THE AFOREMENTIONED SHORTWAVE TROUGH APPROACHES THIS EVENING,
THERE WILL BE A PERIOD OF LIFT COLOCATED WITH A POCKET OF MOISTURE
AROUND 750-850MB ON THE COOL SIDE OF THE BOUNDARY. THE LEFT EXIT REGION
OF A JET STREAK ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE TROUGH
WILL BE ACROSS FAR NORTHERN KANSAS AND INTO NEBRASKA TONIGHT, AND
THIS IS WHERE ANY SUBSTANTIAL PRECIPITATION WILL BE. THE NAM/HRR
SHOW A SMALL AREA OF PRECIPITATION DEVELOPING WITH VERY LIGHT QPF
VALUES BETWEEN 00 AND 06 UTC FROM DODGE CITY TO GREAT BEND. THIS
COULD BE IN THE FORM OF LIGHT DRIZZLE, LIGHT FREEZING DRIZZLE OR
LIGHT SNOW. THIS PRECIPITATION WILL BE DEVELOPING BELOW A MID-
LEVEL INVERSION AND THE LAYER OF LIFT WILL BE FAIRLY SHALLOW. THIS
PRECIPITATION, THAT MAY NOT BE MEASURABLE, COULD BE OVER BEFORE
TEMPERATURES ARE COLD ENOUGH TO RESULT IN SLICK ROADS.
AFTER THIS SYSTEM PASSES LATE TONIGHT, SKIES WILL CLEAR AND
TEMPERATURES SHOULD HAVE NO PROBLEM FALLING INTO THE TEENS GIVEN
THE AFOREMENTIONED COLD AIR OVER THE NORTHERN PLAINS MOVING
SOUTHWARD. SO MOST OF THE COOLING TONIGHT WILL BE FROM COLD
ADVECTION AND MOT RADIATIONAL COOLING. WINDS MAY DROP OFF BY 12-13Z
AND THIS MAY ALLOW FOR SOME RADIATIONAL COOLING AS WELL.
TUESDAY WILL BE FAIRLY CHILLY AS COLD SURFACE HIGH PRESSURE SETTLES
INT CENTRAL KANSAS BY AFTERNOON. SO DESPITE THE SUNSHINE,
TEMPERATURES SHOULD HAVE TROUBLE GETTING MUCH ABOVE FREEZING FROM
DDC TO HAYS AND GCK. ANOTHER COLD NIGHT CAN BE EXPECTED TUESDAY NIGHT.
HOWEVER, LOW-LEVEL LEE TROUGHING WILL DEVELOP ALONG WITH ACCOMPANYING
25-30KT SOUTHWESTERLY WINDS AT 850MB. SO DESPITE THE COLD START,
THERE SHOULD BE ENOUGH VERTICAL MIXING TO DISCOURAGE STRONG
RADIATIONAL COOLING. ALSO, AS THE WINDS PICK UP, WARMER AIR
DEVELOPING FROM DOWNSLOPE FLOW ABOVE THE SURFACE WILL TEND TO MIX TO
THE SURFACE AND THIS WILL ALSO HELP TO KEEP TEMPERATURES A LITTLE
WARMER. BUT STILL, TEMPERATURES SHOULD FALL TO BETWEEN 15 AND 20F
AND THE 10 KT SOUTHERLY SURFACE WINDS WILL MAKE IT FEEL EVEN
COLDER.
A SHORTWAVE TROUGH WILL PROGRESS ACROSS THE NORTHERN PLAINS BY
WEDNESDAY WITH CONTINUED WEAK LEE TROUGHING ACROSS THE CENTRAL AND
SOUTHERN PLAINS. THE WEAK DOWNSLOPE FLOW ALONG WITH AMPLE SUNSHINE
SHOULD BE ENOUGH TO ALLOW TEMPERATURES TO WARM INTO THE UPPER 40S
TO LOWER 50S.
DAYS 3-7...
THE 12Z RUNS OF THE MEDIUM RANGE MODELS ARE ALL SHOWING A ZONAL FLOW
PATTERN ACROSS CENTRAL NORTH AMERICA WITH THE STRONGEST MID/UPPER
LEVEL FLOW ACROSS THE NORTHERN CONUS THROUGH MUCH OF THE EXTENDED
PERIOD. THE MODELS ARE ALL SHOWING FAST MOVING SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW THAT WILL CROSS OVER THE CENTRAL PLAINS
WEDNESDAY NIGHT AND AGAIN ON FRIDAY.
THE WEDNESDAY SHORTWAVE TROUGH WILL MAINLY BE NORTH OF THE CENTRAL
HIGH PLAINS AND WILL HAVE LITTLE IMPACT...OTHER THAN A SHORT LIVED
WIND SHIFT. WITH THE SHORTWAVE TROUGH ON FRIDAY...THE ECMWF IS
SHOWING A LITTLE MORE AMPLITUDE THAN THE CANADIAN AND GFS MODELS BUT
EVEN IT DOESN`T PRODUCE ANY SIGNIFICANT PRECIPITATION AS THE
ATMOSPHERE OVER THE PLAINS WILL NOT BE OVERLY MOIST. THE BULK OF THE
COLDER AIR OVER THE NORTHERN PLAINS WILL IMPACT THE MIDWEST SO ANY
COOLDOWN WILL BE FAIRLY MINOR AS WESTERLY FLOW ALOFT CONTINUES. THE
REST OF THE EXTENDED PERIOD WILL CONTINUE TO BE DRY WITH
TEMPERATURES WARMING TO THE 50S AND 60S.
THE GFS AND ECMWF HAVE BEEN HINTING AT A STRONGER SHORTWAVE OR
CLOSED LOW DEVELOPING OVER THE WESTERN CONUS BY THE BEGINNING OF
NEXT WEEK. THE MODELS HAVE BEEN SHOWING A LOT OF INCONSISTENCY FROM
RUN TO RUN AND WITH EACH OTHER REGARDING THIS SO AM NOT OVERLY
CONFIDENT IN ANY MODEL SOLUTION AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 33 17 50 / 20 0 0 0
GCK 17 33 15 50 / 30 0 0 0
EHA 18 34 15 52 / 10 0 0 0
LBL 19 35 16 51 / 10 0 0 0
HYS 16 31 15 48 / 30 0 0 0
P28 23 35 17 49 / 30 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1218 AM EST TUE JAN 17 2012
UPDATED AVIATION DISCUSSION FOR THE 06Z TAFS
.SYNOPSIS... ISSUED AT 433 PM EST
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW GENERAL WRN TROF/
ERN RDG PATTERN ACRS NAMERICA. THERE IS A STRONG DISTURBANCE/120KT
H3 JET MAX IN ONTARIO EMBEDDED WITHIN THE WSW FLOW ALF...AND
ATTENDANT COLD FNT IS PRESSING TOWARD WRN UPR MI EARLY THIS AFTN.
THERE IS QUITE A BIT OF LO CLD IN THE RELATIVELY MILD SSW FLOW AHEAD
OF THIS FNT WITH 12Z GRB RAOB SHOWING THIN SATURATED LYR ARND
H925...BUT MID LVL DRYNESS SHOWN ON THAT RAOB IS PREVENTING ANY
PCPN. TEMPS DROP OFF SHARPLY BEHIND THE APRCHG COLD FNT WITH
READINGS OVER THE MN ARROWHEAD FALLING TOWARD 10F. 12Z INL RAOB
INDICATED A SHARP INVRN NEAR H9 ABV THIS FAIRLY SHALLOW INFUSION OF
COLD AIR...AND THERE IS QUITE A BIT OF LO CLD/SOME -SN IN THAT AREA
AS WELL. FARTHER UPSTREAM...BITTERLY COLD AIR IS PRESENT OVER THE W
HALF OF CANADA...WITH H85 TEMP AS LO AS -32C AT CALGARY. SOME OF
THIS COLD AIR IS SPILLING INTO THE NRN PLAINS...WHERE SFC TEMPS ARE
NOT MUCH ABV ZERO IN NDAKOTA. SEVERAL DISTURBANCES ARE NOTED WITHIN
THE WRN TROF...AND THERE IS A SOMEWHAT ILL DEFINED COMMA CLD NOTED
ON WV IMAGERY PUSHING INTO THE NRN PLAINS. BUT GENERAL DRYNESS IN
THAT AREA INDICATED BY H7 RAOBS HAS LIMITED THE PCPN COVERAGE.
&&
.SHORT TERM /TNGT AND TUE/... ISSUED AT 433 PM EST
MAIN FCST CONCERNS DURING THIS PERIOD REVOLVE ARND SN CHCS/AMOUNTS
AS COLDER AIR MOVES INTO THE UPR LKS AT SAME TIME DISTURBANCE IN THE
NRN ROCKIES MOVES BY JUST TO THE S.
TNGT...DISTURBANCE MARKED BY ILL DEFINED COMMA CLD IN THE NRN PLAINS
IS PROGGED TO MOVE INTO THE NCNTRL PLAINS BY 12Z TUE...WITH SFC LO
NOW TAKING SHAPE IN THE PLAINS DRIFTING NEAR LOWER MI. MEANWHILE...
COLDER AIR TO THE NW WL SLOWLY INFILTRATE THE UPR LKS AS THE LLVL
WIND TURNS MORE TO THE N...DROPPING H85 TEMPS TO ARND -15C OVER WRN
LK SUP TO -10C OVER THE E. WITH OPEN WATER TEMPS ARND 3C...THE
ARRIVAL OF THIS INCOMING AIRMASS WL BE SUFFICIENT TO GENERATE LES W
TO E. ALTHOUGH THE SHARPER FORCING ASSOCIATED WITH THE PLAINS SHRTWV
WL TEND TO BE FOCUSED JUST S OF UPR MI...THE 12Z NAM/GFS SHOW DEEPER
MSTR ARRIVING MAINLY OVER THE NW HALF OF THE CWA OVERNGT WHERE UPR
DVGC/H7-5 FGEN WL BE MAXIMIZED IN RRQ OF 120KT H3 JET MAX MOVING TO
NEAR JAMES BAY. FCST SDNGS SHOW THE ASSOCIATED OMEGA WL BE MAXIMIZED
FAIRLY HI CLOSER TO THESE HIER LVL FORCING MECHANISMS...SO POTENTIAL
FOR TRUE LK ENHANCEMENT IS PROBABLY MINIMAL. WITH GREATER OVERWATER
INSTABILITY AND SHARPER LLVL CNVGC OVER THE FAR W NEAR IWD PER NAM
FCST...EXPECT HEAVIER SHSN THERE IN THE PRESENCE OF FVRBL UPSLOPE N
WIND. ALTHOUGH THE LLVL FGEN WL BE SHARPER OVER THE SE ZNS CLOSER TO
THE SFC LO/FNT TO THE SE... THE AIRMASS APPEARS WL BE TOO DRY
OVERALL FOR ANY SGNFT PCPN THERE THRU 12Z.
TUE...UPR DISTURBANCE/SFC LO TO THE S WL SHIFT TO THE E...WITH
TRAILING SFC HI PRES FCST TO SHIFT TOWARD WRN MN BY LATE IN THE DAY.
DEEP MSTR ASSOCIATED MAINLY WITH HI LVL FORCING RELATED TO COUPLED
UPR DVGC IN RRQ OF UPR JET TO THE NE/LEFT EXIT OF JET SUPPORTING
SHRTWV IN THE LOWER LKS AND H7-5 FGEN WL EXIT W-E IN THE AFTN. BEST
CHC FOR WDSPRD PCPN WL BE INTO MID AFTN...WHEN MODELS SHOW SHARPER
UPR DVGC AND LINGERING FGEN TENDING TO EXIT TO THE E. ALTHOUGH PURE
LES WL LINGER EVEN AFT THE EXIT OF THE DYNAMICS AS H85 TEMPS TUMBLE
TOWARD -20C WITH INFLUX OF ARCTIC AIR TO THE NW...STEADILY BACKING
WINDS IN THE AFTN WL TEND TO LIMIT LES BAND RESIDENCE TIME AND
ACCUMS. AWAY FM LK MOISTENING...PLAN ON NO MORE THAN 1 TO 2 INCHES
OF SN WITH BETTER OMEGA ABV THE DGZ AND H85 CAD TENDING TO OFFSET
THE UPR DVGC/FGEN. EXPECT LTL DIURNAL RISE OF TEMP AS BITTERLY COLD
AIRMASS IN THE NRN PLAINS FOLLOWS INTO THE UPR LKS.
AS FOR HEADLINES...RETAINED GOING ADVY FOR GOGEBIC/ONTONAGON ZNS
WITH MOST FAVORABLE OVERWATER INSTABILITY/FETCH/UPSLOPE WIND
COMPONENT. OPTED TO ISSUE AN ADVY FOR BARAGA/MQT AS WELL FOR THE
09Z-21Z TIME WITH THE SAME FAVORABLE PARAMETERS. WITH WSHFT TO THE
NW ON TUE AFTN...THE HEAVIER SHSN SHOULD END IN THIS AREA EVEN
EARLIER THAN OVER THE W. COORDINATED WITH DLH ON HEADLINES FOR IWD
AREA.
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
TUESDAY NIGHT...
THE 500MB THROUGH CURRENTLY SET UP ACROSS MT THROUGH NV AND S CA
WILL BE DIRECTLY OVERHEAD AT 00Z WEDNESDAY...WITH THE MAIN LOW
SLOWLY SWINGING ACROSS CENTRAL TO NE CANADA. THE SFC LOW /FARTHER
EAST/ SHOULD BE JUST NORTH OF LAKE ONTARIO AT 00Z WEDNESDAY...WITH A
TROUGH EXTENDING THROUGH UPPER MICHIGAN INTO FAR WESTERN LAKE
SUPERIOR. N-NW WINDS WILL PREVAIL INITIALLY WITH 850MB TEMPS
AVERAGING -18C.
WEDNESDAY INTO THURSDAY...
BY 12Z WEDNESDAY THE TROUGH WILL RESIDE ACROSS EASTERN
UPPER MI...BEFORE BEING QUICKLY PUSHED EASTWARD BY MID MORNING
THANKS TO THE STRONG SFC RIDGE TO OUR SOUTH...AND ANOTHER LOW
NEARING FROM THE DAKOTAS. THE RESULT WILL BE WINDS BECOMING WESTERLY
AND SOUTHWESTERLY THROUGH THE DAY...WITH LES HOLDING ON THE LONGEST
ACROSS THE KEWEENAW PENINSULA AND FAR EAST NEAR LAKE SUPERIOR /INTO
THE MID MORNING HOURS/.
A WEAK RIDGE TO ZONAL FLOW CAN BE EXPECTED ALOFT WEDNESDAY...BEFORE
THE NEXT TROUGH SWINGS IN FROM MN WEDNESDAY NIGHT INTO THURSDAY
MORNING /ASSOCIATED WITH THE SFC LOW/. EXPECT THE SFC LOW TO PUSH
OVER THE WESTERN THIRD OF THE CWA BY 00Z...CENTRAL BY 06Z...AND
RESIDE JUST TO OUR EAST BY 12Z THURSDAY. THE 06Z RUN OF THE GFS IS
THE WEAKEST AND FARTHEST SOUTH WITH THIS FEATURE /APPROX 220 MILES
SSE OF THE ECMWF/. THIS MAKES TIMING THE ONSET OF PRECIPITATION
DIFFICULT...WITH THE ECMWF INDICATING A SHORT DRY PERIOD FOR MUCH OF
THE AREA WEDNESDAY AFTERNOON...WHILE THE KEWEENAW STAYS IN THE SNOW
IF THE GFS IS TO BE BELIEVED. AT THIS POINT...THE GFS LOOKS TO BE AN
OUTLIER...WITH LIMITED INPUT INTO THIS FORECAST FROM WEDNESDAY ON.
THE 12Z GFS HAS MOVED CLOSE TO THE CONSENSUS...SPLITTING THE
ORIGINAL 220 MILE DIFFERENCE IN HALF. ANY OF THE SOLUTIONS WOULD
BRING A CHANCE OF LES ON SOUTHERLY WINDS TO THE EASTERN CWA LATE
WEDNESDAY AFTERNOON INTO THE EVENING HOURS...BEFORE THEY BECOME TOO
MUCH OUT OF A SW OR W DIRECTION /850MB TEMPS OF -11 TO -14C SHOULD
BE COLD ENOUGH/.
THE MAIN 500MB LOW WILL REMAIN WELL TO OUR NORTH...SLOWLY
RETROGRADING WESTWARD FROM THE HUDSON BAY AREA TO AK BY THE END OF
THE WORK WEEK. A SIGNIFICANT TROUGH WILL STILL LINGER ACROSS N
HUDSON BAY FOR THE FORESEEABLE FUTURE.
THE COLDEST AIR SEEN IN SOME TIME WILL SLIDE IN THURSDAY...DROPPING
TO -24C BY THE AFTERNOON HOURS ON GUSTY NW WINDS...WITH LIKELY SNOW
SHOWERS RETURNING TO THE AREA NEAR LAKE SUPERIOR. THIS WILL BE THE
CASE UNTIL WAA SW WINDS TAKE HOLD AGAIN FRIDAY MORNING. WILL KEEP
THIS SYSTEM MENTIONED IN THE HWO...AND CONTINUE TO MONITOR IT
CLOSELY FOR THE POTENTIAL FOR HEADLINES AS IT MOVES CLOSER.
FRIDAY THROUGH MONDAY...
FCST MODELS BEGIN TO DIVERGE IN THE OVERALL PATTERN LATE
FRIDAY...WITH THE ECMWF AND CANADIAN KEEPING A TROUGH OVERHEAD WITH
THE GFS INDICATES MORE IN THE WAY OF SW FLOW. THESE DIFFERENCES
CONTINUE AND BECOME MORE DRAMATIC TROUGH MONDAY. THIS IS SEEN ON THE
SFC CHARTS AS WELL AT 00Z SUNDAY WITH THE LOCATION OF THE NEXT LOW
VARYING SOME 1K MILES BASED ON THE 16/06Z GFS AND 16/00Z ECMWF. THE
GFS HAS IT JUST NW OF LAKE SUPERIOR...WHILE THE ECMWF IS STILL
ORGANIZING THE FEATURE OVER SOUTHERN ALBERTA. GIVEN ALL THE
DIFFERENCES...WILL NOT DEVIATE MUCH FROM AN AVERAGE/BLENDED SOLUTION.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
UNDER COOLING AIRMASS...MVFR CONDITIONS AT KIWD/KCMX/KSAW WILL
TRANSITION TO IFR FROM W TO E OVERNIGHT THRU THE MORNING AS LAKE
EFFECT SNOW SHOWERS DEVELOP...AIDED BY DEEPER MOISTURE ASSOCIATED
WITH INCOMING UPPER LEVEL DISTURBANCE. BEST CHC FOR LIFR SHOULD
OCCUR LATE IN THE NIGHT THRU THE MORNING AT KIWD WHERE OVERWATER
INSTABILITY WILL BE MAXIMIZED IN THE PRESENCE OF
FAVORABLE/CONVERGENT UPSLOPE N WIND. SOME PERIODS OF LIFR NOT OUT OF
THE QUESTION AT KSAW MID TO LATE MORNING AS WELL UNDER FAVORABLE
UPSLOPE. IMPROVEMENT SHOULD OCCUR AT ALL TERMINALS MID TO LATE AFTN
AS DEEPER MOISTURE DEPARTS AND LOW-LEVEL CONVERGENCE BEGINS TO
WEAKEN. CONTINUED BACKING OF WINDS IN THE EVENING SHOULD BRING AN
END TO -SHSN AT KIWD WITH ONLY SOME FLURRIES LINGERING AT KSAW.
OVERLAKE TRAJECTORY WILL MAINTAIN -SHSN/MVFR CONDITIONS AT KCMX THRU
THE EVENING HRS.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT N WINDS UP TO 30 KTS/SOME FREEZING SPRAY ON TUE WITH INFLUX
OF COLDER AIR IN THE WAKE OF LO PRES SHIFTING E THRU THE LOWER LKS.
WINDS WL DIMINISH AND BACK TO THE SW TUE NGT THRU WED WITH THE
PASSAGE OF A RIDGE AXIS AND AHEAD OF ANOTHER LO PRES SYSTEM. A
BITTERLY COLD AIRMASS WILL FOLLOW THIS LO AS NW WINDS INCREASE TO
AOA GALE INTENSITY /MAINLY THURSDAY/. HEAVY FREEZING SPRAY WILL BE A
GOOD BET OVER MOST OF THE LAKE /MAINLY WEDNESDAY NIGHT INTO THURSDAY
WEST/ BEFORE WINDS DIMINISH AGAIN BY LATE IN THE WEEK WITH THE
APPROACH OF ANOTHER HI PRES RDG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 5 PM EST TUESDAY FOR
MIZ004-005.
LAKE EFFECT SNOW ADVISORY FROM 1 AM EST /MIDNIGHT CST/ TO
7 PM EST /6 PM CST/ TUESDAY FOR MIZ002-009.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1158 PM EST MON JAN 16 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(400 PM EST MON JAN 16 2012)
LOW PRESSURE WILL TRACK FROM MISSOURI TO LAKE ONTARIO TONIGHT AND
TUESDAY. THIS SYSTEM WILL PRODUCE A WIDESPREAD 3 TO 6 INCH SNOWFALL
OVER NORTHERN LOWER MICHIGAN... AND A WINTRY MIX OF SNOW AND
FREEZING RAIN ACROSS CENTRAL LOWER MICHIGAN.
MEANWHILE RAIN AND AREAS OF FOG WILL IMPACT SOUTHERN LOWER MICHIGAN
TONIGHT. THE RAIN WILL CHANGE TO SNOW SHOWERS TUESDAY AFTERNOON ONCE
THE LOW PASSES BY AND COLDER AIR RUSHES IN. LAKE EFFECT SNOW SHOWERS
TUESDAY NIGHT COULD PRODUCE 1 TO 3 INCHES OF ADDITIONAL SNOW ALONG
AND WEST OF HIGHWAY 131.
MORE SNOW SHOWERS...WITH SOME ACCUMULATIONS...ARE ANTICIPATED
WEDNESDAY NIGHT AND THURSDAY AS THE NEXT COLD FRONT PUSHES THROUGH
THE REGION AND BRINGS A REINFORCING SHOT OF COLD ARCTIC AIR.
&&
.SHORT TERM...(930 PM EST MON JAN 16 2012)
(TONIGHT THROUGH WEDNESDAY AFTERNOON)
A DENSE FOG ADVISORY IS BEING ISSUED FOR THE OVERNIGHT PERIOD
THROUGH MID MORNING TUESDAY FOR ROUGHLY THE SOUTHERN HALF OF OUR
FCST AREA. A COUPLE OF OBS SITES ARE REPORTING VSBY DOWN TO A
QUARTER MILE AND MOST OTHER OBS SITES ACROSS OUR SOUTHERN FCST AREA
ARE SHOWING A SLOW BUT STEADY TREND DOWNWARD WITH VISBYS. SHORT
RANGE GUIDANCE SUCH AS THE 13KM RUC SUGGESTS FOG WILL ONLY BECOME
MORE DENSE/WIDESPREAD OVERNIGHT AND THIS MAKES PHYSICAL SENSE GIVEN
HIGH BOUNDARY LAYER MOISTURE AND TEMPS RIGHT AT OR NEAR THE DEW PT.
REMAINDER OF PREVIOUS SHORT TERM FCST DISCUSSION FOLLOWS...HAVE
ISSUED A WINTER WEATHER ADVISORY FOR THE NRN CWFA FOR LATE
TONIGHT AND TUESDAY FOR A MIXTURE OF SNOW AND FREEZING RAIN CHANGING
TO ALL SNOW. AM THINKING 3-5 INCHES OF SYNOPTIC SNOWS NORTH OF A
LINE FROM ROUGHLY HART TO CLARE WHERE PCPN WILL BE MOSTLY SNOW. JUST
SOUTH OF THERE.... INCLUDING BIG RAPIDS... MT PLEASANT AND ALMA...
WILL FCST 1 TO 3 INCHES OF SNOW WITH UP TO A TENTH OF AN INCH OF
FREEZING RAIN.
MODELS INSIST THAT LIGHT RAIN/DRIZZLE WILL RAPIDLY DEVELOP EARLY
THIS EVENING IN RESPONSE TO TIGHTENING FRONTAL ZONE OVERHEAD AND
APPROACHING SHORTWAVE. FORTUNATELY TEMPERATURES HAVE WARMED ABOVE 40
IN MOST AREAS AND FREEZING RAIN WILL NOT BE A THREAT TO START OUT.
HOWEVER LATER THIS EVENING THE FAR NRN CWFA MAY COOL BACK DOWN TO
NEAR FREEZING...WITH A MUCH BETTER RISK OF FALLING BELOW FREEZING
VERY LATE TONIGHT AS THE LOW LEVEL NE FLOW DEVELOPS/STRENGTHENS ON
THE NORTH SIDE OF THE STRENGTHENING FRONTAL ZONE.
THE BULK OF THE EVENT OCCURS ON TUESDAY WHEN THE DEFORMATION ZONE
IMPACTS THE REGION. PRIOR TO THAT THE MOISTURE IS RATHER SHALLOW AND
THE DGZ IS NOT SATURATED. BEST OMEGA/DGZ COMBINATION SETS UP ACROSS
THE NW CWFA AROUND LDM. MEANWHILE BECAUSE OF THE SFC LOW TRACK...
PROGS SHOW COLD AIR TAKING IT/S TIME ARRIVING IN THE SE CWFA AROUND
JXN ON TUESDAY. IT TAKES UNTIL AFTER 18Z-21Z TO COOL SUFFICIENTLY TO
SUPPORT SNOW. THUS WILL FCST UNDER AN INCH OF ACCUMS FROM LAN SOUTH.
THE LAKE EFFECT ON TUESDAY NIGHT LOOKS FAIRLY SHORT LIVED AS SURFACE
RIDGING AND LOWERING INVERSION HEIGHTS ARRIVE AFTER 06Z. HOWEVER
SOME QUICK ADDITIONAL 1-4 INCH ACCUMULATIONS ARE CERTAINLY POSSIBLE
ALONG/WEST OF HWY 131 PRIOR TO THE LATE NIGHT DIMINISHING TREND.
WEDNESDAY LOOKS QUIET AS SHORTWAVE RIDGING IMPACTS THE REGION IN
BETWEEN SYSTEMS.
&&
.LONG TERM...(400 PM EST MON JAN 16 2012)
(WEDNESDAY NIGHT THROUGH MONDAY)
A CLIPPER IS GOING TO BRING ANOTHER SHOT OF ARCTIC AIR TO THE
REGION. LIKE PREVIOUS COLD AIR INTRUSIONS...THIS ONE WON/T LAST LONG
EITHER...A COUPLE OF DAYS. SHORT RANGE MODELS SHOW THE COLD FRONT
MOVING ACROSS THE CWA WEDNESDAY NIGHT. WE/LL SEE SHSN DEVELOP ALONG
AND BEHIND THE COLD FRONT. WE HAVE LIKELY POPS OVER THE WRN CWA WED
NIGHT AND THURSDAY. WE SHOULD SEE SEVERAL INCHES OF ACCUMULATIONS IN
THE USUAL NW SNOW BELT AREAS AS H8 -20C AIR MOVES ACROSS THE LAKE.
INVERSION HEIGHTS FALL DURING THE DAY AND NIGHT BEFORE SW FLOW WAA
FRIDAY BRINGS IN SOME MORE MOISTURE. WSW FLOW LAKE ENHANCED FLOW
WILL MEAN ACCUMULATING SNOW POSSIBLE AGAIN FRIDAY. H8 TEMPS WARM
ENOUGH FRIDAY NIGHT/SATURDAY SUCH THAT LAKE EFFECT SNOW SHOULD STOP.
WAA CONTINUES INTO SUNDAY WHERE TEMPS SHOULD CLIMB ABOVE 40 AGAIN
AHEAD OF THE NEXT CLIPPER SUNDAY NIGHT. MIXED RAIN/SNOW SUNDAY INTO
MONDAY AS THE CLIPPER AND TRAILING COLD FRONT MOVE THROUGH. THERE
DOESN/T APPEAR TO BE A STRONG SURGE OF ARCTIC AIR BEHIND THE SUNDAY
CLIPPER.
&&
.AVIATION...(1158 PM EST MON JAN 16 2012)
THE DENSE FOG AND DRIZZLE HAVE BECOME RATHER EXTENSIVE ALONG THE
I-96 TAF SITES AND WILL SOON SPREAD TO THE I-94 SITES AS THE LOW
PRESSURE SYSTEM GETS CLOSER TO THE AREA (LIGHTER WINDS). THE DENSE
FOG WILL PREVAIL UNTIL THE CENTER OF THE SURFACE LOW PASSES EAST OF
THE TAF SITES... AROUND 15Z OR SO. SOME RAIN IS EXPECTED OVERNIGHT
BUT AT THIS POINT FREEZING RAIN OR DRIZZLE SEEM UNLIKELY AT ANY OF
THE TAF SITES.
ONCE THE SURFACE LOW IS EAST OF THE AREA... SAY AROUND 15Z... THE
COLD AIR WILL BE PULLED IN FROM THE NORTH AND TURN THE RAIN TO SNOW.
SOME FREEZING RAIN IS POSSIBLE ALONG THE I-96 TAF SITES. ALL SNOW IS
EXPECTED THROUGH THE AFTERNOON AT THOSE SITES. THE I-94 TAFS WILL
SEE SNOW BY MID AFTERNOON.
&&
.MARINE...(400 PM EST MON JAN 16 2012)
WILL LET THE SMALL CRAFT ADVISORY EXPIRE AT 4 PM... BUT ISSUE A
GALE WARNING FOR TUESDAY DUE TO STRONG NW FLOW ON THE BACK SIDE OF
THE DEPARTING SYSTEM.
&&
.HYDROLOGY...(400 PM EST MON JAN 16 2012)
NO ICE JAMS HAVE BEEN REPORTED... BUT WILL MONITOR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL 11 AM TUESDAY FOR MUSKEGON...
OTTAWA... KENT... IONIA... CLINTON... ALLEGAN... BARRY...
EATON... INGHAM... VAN BUREN... KALAMAZOO... CALHOUN
AND JACKSON COUNTIES.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
TUESDAY FOR MASON LAKE OSCEOLA CLARE OCEANA NEWAYGO MECOSTA
ISABELLA MONTCALM AND GRATIOT COUNTIES.
LM...GALE WARNING ST JOSEPH TO MANISTEE TUESDAY INTO TUESDAY
EVENING... 7 AM TO 11 PM.
&&
$$
SYNOPSIS: MEADE
SHORT TERM: MEADE/LAURENS
LONG TERM: 93
AVIATION: WDM
MARINE: MEADE
HYDROLOGY: MEADE
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
318 AM CST Tue Jan 17 2012
.DISCUSSION...
Two waves of precipitation ongoing this morning as an upper level
trough moves across the region. The first across portions of central
into Eastern Missouri in the form of showers and strong to severe
thunderstorms and the other across southern Iowa, southeast Nebraska
and northern Missouri. This second area has been a mix of snow
freezing rain and sleet through the overnight hours. Short term
guidance and ongoing trends suggests this activity to have moved out
of most of the forecast area by 12z. Will maintain a small area of
light snow or flurries across far north-central to northeast
Missouri through 15z for any lingering precipitation.
Deep isentropic downglide should erode the residual cloud cover
through this morning with most of the area clearing by later this
afternoon. Otherwise, strong CAA ongoing this morning with the
freezing line virtually bisecting the forecast area at the moment.
This trend will persist through the day as brisk and gusty northwest
low level flow is expected to continue as sfc ridge settles into the
plains. Looking at upstream temperatures and the expected CAA regime
through the day, expect most if not all areas will remain near or
below freezing today.
Canadian air mass will fully settle across the area tonight as the
aforementioned sfc ridge continues southeast. Light winds and clear
skies will result in efficient radiational cooling tonight allowing
temperatures to fall into the teens and single digits.
The cold spell will be fairly short lived as the sfc ridge quickly
slides east and southerly low level flow returns by Wednesday
morning. The next upper level trough will slide across the northern
tier of the country Wednesday with accompanying sfc low moving into
the Great Lakes by Wednesday evening. In response, brisk
southwesterly low level flow will advect warmer temperatures into
the area by Wednesday afternoon with near to slightly above average
readings expected.
Yet another cold front will move through the area Wednesday night
into Thursday morning continuing the temperature roller coaster.
Weak, elongated vorticity on the southern flank of the upper level
system will traverse the northern portions of the forecast area late
Wednesday night. This may provide sufficient ascent to produce some
scattered flurries, mainly across far northern Missouri.
Deroche
Medium range (Friday through Monday)...
Zonal flow will be set up across the CONUS come Friday. Models
advertise a weak upper level shortwave moving from the Northern
Plains into the Upper Midwest. Moisture content available for this
system will be meager as it moves through. A frontal boundary
extending from the Tennessee River Valley through the Deep South will
keep Gulf moisture pinned south and east of the forecast area. There
may be enough weak mid and upper level forcing to allow for a slight
chance of light showers across the eastern half of the CWA. High
pressure will move into the area Friday night with cold overnight
lows in the mid teens to mid 20s before a warming trend. The surface
high will slide off to the east on Saturday bringing a return of warm
southerly flow to the area as weak upper level ridging builds into
the region. High temperatures by Sunday will range from the upper 40s
to upper 50s. By Monday, zonal flow begins to break down across the
CONUS as a upper level trough moves into the west coast. Models
differ on the track, timing, and strength of this next system as the
GFS is much faster in bringing an open wave through the Rockies and
into the Plains on Monday. This faster and weaker solution will bring
rain showers to the area on Monday. The slower EC brings the trough
into the west coast and then digs it southward into the Southern
Rockies cutting off an upper low across the Four Corners region by
Monday night, delaying the onset of precipitation. To account for the
faster GFS have added chance pops to the forecast on Monday.
73
&&
.AVIATION...
Thunderstorms remain well south of terminals and mixed winter
precipitation mainly northwest of terminals for the 06Z taf package
as midlevel dryslot advects over eastern Kansas and western
Missouri. Regional radar loops (supported by HRRR trends) indicates
most, if not all precipitation splitting around aerodrome sites
tonight; and have removed -rasn mention (sans a 1 hour tempo mention
at KSTJ where a wintry mix remains possible). Will need to watch
tail end of snow band over central Kansas should it begin to rotate
a bit further SE.
Based on upstream observations and bufr soundings have pushed cigs
into the upper end of mvfr late tonight and Tuesday morning. Could
potentially still see a period of lower end mvfr with overall
confidence not particularly high. Brisk sustained NW sfc winds will
quickly obtain gustiness as secondary caa blast moves into the area
per KS/NE obs; and remain sustained aoa 13kt throughout the daylight
hours Tuesday before decoupling with sunset.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1135 PM CST Mon Jan 16 2012
...UPDATED AVIATION...
.DISCUSSION...
Dry air and good mixing prevented many low clouds from developing
today which allowed temperatures to soar well into the 60s across the
southeast 3/4 of the forecast area. Meanwhile a cold front continues
to organize and slowly push south into far northern Missouri late
this afternoon. This front will accelerate southward this evening as
a weak shortwave tracks into the Central Plains. As this feature
interacts with the front and low level wind fields increase, a band
of frontogenesis will develop in the 900-800 hPa layer across the
southern half of the area late this evening. This should allow
scattered light precipitation to develop across eastern Kansas into
central Missouri after sunset, which will likely grow in intensity
and coverage across far southern portions of the area after 06Z as
frontogenesis intensifies. An elevated theta-e maximum near 850-hPa
may allow for some elevated thunder as well, especially across the
southern third of the forecast area.
Meanwhile further north, an additional band of postfrontal light
snow will expand out of the Dakotas into Nebraska and Iowa overnight
ahead of the upper wave. Expect the bulk of this activity to remain
north of the forecast area in a region of better upper level support,
though some light accumulating snow (or sleet) may be possible as far
south as Highway 36 where weak deformation and convergence will set
up along the lagging 850 hPa front. Interestingly, the 18Z run of the
NAM is producing between 0.2 and 0.3 inches of QPF across the
northern forecast area overnight. This seems to be an anomalous run
as its forecast deep moisture profile is much more moist than
previous runs, which doesn`t seem supported by looking upstream.
Between this and the shower and thunderstorm activity further south,
there may be a relative minimum in precipitation across the KC-Macon
corridor for much of the night. However, still can`t rule out some
light precip across these areas toward midnight given the broad
ascent ahead of the upper wave. Thermal profiles suggest that any
precipitation that does develop overnight would initially be rain
south of Highway 36, before transitioning to a light wintry mix
across the KC- Macon corridor around 08Z and across central Missouri
by 11Z. At this time precipitation amounts look to be much too light
by the time this transition occurs to produce any measurable snow or
ice accumulation.
This system will shift into the Great Lakes on Tuesday with deep cold
air advection spreading into the region. Skies should gradually clear
from west to east through the day, though concerned that models may
be moving the clearing line too quickly across the forecast area as
they often do in similar CAA regimes. A large surface high will be
quick to build into the region by Tuesday afternoon, shifting into
the Mississippi Valley by 12Z Weds. This will allow temperatures to
fall into the teens, though didn`t go quite as cold as guidance
numbers given how quickly winds will increase from the south after
09Z. Warm air advection will send temperatures back above average by
Wednesday while skies remain mostly sunny.
Hawblitzel
Medium Range (Thursday - Sunday):
Models show reasonable agreement with the upper level pattern
through the extended with nearly zonal to northwesterly flow
prevailing. There is also decent agreement tracking a wave through
the flow Friday into Saturday. The ECMWF is a little more aggressive
with the mid level circulation associated with short wave and as a
result depicts a bit more QPF. Prefer the GFS which keeps the mid
level wave open and therefore not as aggressive with any possible
precipitation. Will keep only slight chances in for the northeastern
half of the forecast area for Friday as this systems tracks through
given the preference for a drier short wave passage. Beyond the
small chances for precipitation on Friday for a portion of the
forecast area the rest of the forecast looks to be above to well
above normal with highs returning to the 50s on Sunday. The next
shot of precipitation may come early next week with models showing a
deep trough coming out of the southwest. This seems to correspond to
the arctic oscillation heading to more of a neutral to slightly
negative outlook per the GFS ensemble data which would indicate
colder temperatures for the area. But this is well into the future
and beyond the scope/timeframe of this forecast so we`ll continue to
monitor trends and see how the pattern evolves over the next 7-8
days.
CDB
&&
.AVIATION...
Thunderstorms remain well south of terminals and mixed winter
precipitation mainly northwest of terminals for the 06Z taf package
as midlevel dryslot advects over eastern Kansas and western
Missouri. Regional radar loops (supported by HRRR trends) indicates
most, if not all precipitation splitting around aerodrome sites
tonight; and have removed -rasn mention (sans a 1 hour tempo mention
at KSTJ where a wintry mix remains possible). Will need to watch
tail end of snow band over central Kansas should it begin to rotate
a bit further SE.
Based on upstream observations and bufr soundings have pushed cigs
into the upper end of mvfr late tonight and Tuesday morning. Could
potentially still see a period of lower end mvfr with overall
confidence not particularly high. Brisk sustained NW sfc winds will
quickly obtain gustiness as secondary caa blast moves into the area
per KS/NE obs; and remain sustained aoa 13kt throughout the daylight
hours Tuesday before decoupling with sunset.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1059 PM CST MON JAN 16 2012
.UPDATE...
/920 PM CST MON JAN 16 2012/
HAVE MADE UPDATES TO GO WITH LIKELY POPS THE REST OF THE EVENING
WHERE SHOWERS AND THUNDERSTORMS HAD DEVELOPED OVER MID MISSOURI.
THE HRRR HAS DONE A DECENT JOB THIS EVENING DEPICTING THIS
DEVELOPMENT...AND SHOWS IT MOVING EAST NORTHEASTWARD TOWARD THE MS
RIVER. SHOWERS AND THUNDERSTORMS HAVE ALSO DEVELOPED OVER SOUTHEASTERN
KANSAS AHEAD IN RESPONSE TO INCREASING ASCENT AHEAD OF A SHORTWAVE
CURRENTLY MOVING ACROSS THE CENTRAL PLAINS. EXPECT THIS AREA TO
SPREAD EAST INTO CENTRAL AND SOUTHEAST MISSOURI BY 06Z...SO LIKELY
AND CATEGORICAL POPS OVER THE SOUTHEAST TWO THIRDS OF THE CWA
OVERNIGHT STILL LOOKS GOOD. RUC STILL DEPICTS THAT BEST VERTICAL
MOTION WILL BE EXITING THE AREA JUST AHEAD OF WHEN LOW LEVEL
THERMAL PROFILES WILL SWITCH OVER TO SNOW OR SLEET. GOING FORECAST
FOR A BRIEF SWITCH OVER TO SNOW WITH LITTLE ACCUMULATION OVER
NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS STILL LOOKS
GOOD...WITH FLURRIES LINGERING INTO TUESDAY MORNING.
BRITT
&&
.DISCUSSION...
/313 PM CST MON JAN 16 2012/
IT WAS THE CLOUDS. SC CLOUD FIELD WAS ABOUT 4-6 HOURS DELAYED IN
GETTING IN HERE AND NEVER DEVELOPED THAT WELL SINCE IT OCCURRED
DURING THE DAY...AND WITH FULL SUNSHINE FOR A GOOD PART OF THE DAY
AND A STOUT SW WIND GUSTING TO 40MPH AT TIMES...TEMPS SURGED TO NEAR
RECORD LEVELS THIS AFTERNOON IN SOMETHING THAT WAS MORE REMINISCENT
OF MID APRIL THAN MID JANUARY. IN FACT...A RECORD MAX TEMP WAS
BROKEN AT KCOU OF 70 DEGREES...WITH THE RECORD TEMP OF 71 AT KSTL
BEING THREATENED. WEAK LO PRES EXISTED OVER N CNTRL MO AT 20Z WITH
A CDFNT EXTENDING TO THE NE AND SW OF THIS LO PRES THRU ERN IA AND
ERN KS. A WRMFNT HAS PUSHED INTO THE FAR NERN FA IN CNTRL IL.
APPROACH OF LEAD MID LEVEL SHORTWAVE THIS EVENING AND SFC CDFNT
IMMERSING ITSELF IN AN EVER INCREASINGLY MOIST ATMOSPHERE SHOULD
FINALLY LEAD TO BREAKOUT OF PCPN...ESPECIALLY LATE THIS EVENING...
WITH IT REACHING ITS PEAK OVERNIGHT...WITH HI PROBABILITIES COVERING
AREAS ALONG-SE FROM CNTRL MO TO CNTRL IL. ENOUGH ELEVATED
INSTABILITY WILL MOVE IN WITH THIS PCPN TO WARRANT CONTINUED MENTION
OF DECENT PROBS FOR TSRA...WITH CAPES OF 200-300 J/KG...MAINLY FOR
AREAS ALONG-S OF I-70. COULD STILL SEE BRIEFLY A POTPOURRI OF PCPN
TYPES LATE TONIGHT FOR PARTS OF NE-CNTRL MO AND W CNTRL IL BEFORE
FIRST DRY PUNCH COMES IN...BUT EXPECTED BREVITY AND INTENSITY OF
PCPN SHOULD BE SUCH WHERE LITTLE OR NO ACCUM WILL BE SEEN. AHEAD OF
THE FRONT...TEMPS SHOULD REMAIN QUITE MILD...WITH READINGS OF 50+
BUT LOOK FOR A RAPID TEMP DROP OFF INTO THE 30S BEHIND THE FRONT...
EVENTUALLY INTO THE MID-UPR 20S FOR PARTS OF NE-CNTRL MO AND W CNTRL
IL. SO NOT QUITE THE SAME PUNCH AS THE LAST FRONT AND SNOW EVENT
WITH OUR DROP INTO THE UPPER TEENS. FAVORED THE WARMER MOS FOR MIN
TEMPS TONIGHT FOR AREAS N AND W OF STL METRO WHILE OUTRIGHT GOING
ABOVE IT FOR AREAS WHERE THE FRONT WILL MAKE A VERY LATE PASSAGE.
RAIN SHOULD LINGER OVER AREAS S AND E OF STL METRO PAST 12Z WHERE
FROPA IS NOT EXPECTED TO OCCUR YET...WITH JUST DRIZZLE OR FLURRIES
LEFTOVER ELSEWHERE DURING THE MORNING UNTIL SECOND AND FINAL DRY
PUNCH PUSHES THRU WITH TRANSITION TO ANTICYCLONIC SFC FLOW. MOS
TEMP TRENDS FROM TONIGHT SHOULD CONTINUE WITH MOS BLEND FAVORED FOR
AREAS N AND W OF STL METRO WHILE ABOVE THE HIGHEST MOS FOR AREAS S
AND E OF STL METRO DUE TO THE DIFFERENT WAYS MOS MAX/MIN TEMPS ARE
CALCULATED VERSUS THE FCST. DECENT BUST POTENTIAL ON TEMPS TONIGHT
AND TOMORROW DUE TO THE TIMING OF THE FRONT AND SHARP GRADIENT IT
WILL CARRY WITH IT...AN HOUR OR TWO OFF ON TIMING WILL MAKE A BIG
DIFFERENCE.
MODELS ARE A TAD FASTER ON TRANSLATIONAL SPEED OF HI PRES AXIS
TUESDAY NIGHT...AND HAVE TWEAKED MIN TEMPS UP FOR KUIN-KCOU AREAS
BUT CONTINUED AOB LOWEST MOS ELSEWHERE.
GFS HAS COME IN CONSIDERABLY COLDER WITH WEDNESDAY NIGHT/EARLY
THURSDAY CDFNT WHILE THE NAM AND ECMWF NOT SO MUCH. FOR NOW WENT
WITH A BLEND AS MOST MODELS WANT TO GIVE US A GLANCING BLOW WITH
THIS AIRMASS AND NOT A DIRECT HIT.
MEDIUM RANGE FOR THE WEEKEND AND EARLY NEXT WEEK STILL LOOKS IFFY ON
THE DETAILS BUT BROAD PICTURE STILL LOOKS CONSISTENT...SHOWING A
PROGRESSIVE FLOW TRANSITIONING TO AN APPROACHING TROF FROM THE W.
THIS SHOULD INDICATE OVERALL MILD TEMPS WITH SPOTTY PCPN CHCS. THE
FRIDAY EVENT STILL LOOKS THE SAME WITH LO PROBS FOR LIGHT MIXED PCPN
WITH BETTER CHCS AHEAD OF THE DEEP TROF ON MONDAY.
TES
&&
.AVIATION...
/1025 PM CST MON JAN 16 2012/
SFC LOW JUST E OF UIN WITH CDFNT EXTENDING SW OF LOW THROUGH COU
AND SWRN MO...JUST N OF JLN. THIS SFC LOW WILL DEEPEN AS IT MOVES
NEWD DRAGGING THE CDFNT SEWD THROUGH STL/SUS LATE TGT. THE SFC
WIND WILL VEER AROUND TO A W-NWLY DIRECTION AFTER FROPA LATE TGT
IN STL/SUS. SHOWERS AND STORMS WILL CONTINUE TO MOVE NEWD ALONG
THE CDFNT LATE TGT. THE CEILING WILL CONTINUE TO LOWER AFTER FROPA
DOWN TO AROUND 1000-1500 FT. MAY HAVE A BRIEF PERIOD OF SNOW IN
UIN BEFORE THE PRECIPITATION SHUTS OFF LATE TGT/EARLY TUE
MRNG...OTHERWISE LITTLE IF ANY WINTRY PRECIPITATION IS EXPECTED AT
THE OTHER TAF SITES. THE CLOUD CEILING WILL GRADUALY RISE DURING
THE DAY ON TUE AS A STRONG SFC RIDGE BUILDS SEWD INTO MO. NWLY SFC
WINDS WILL BE QUITE STRONG AND GUSTY ON TUE DUE TO THE TIGHT SFC
PRESSURE GRADIENT BETWEEN THIS SFC RIDGE AND THE DEEPENING SFC LOW
MOVING NEWD THROUGH THE GREAT LAKES REGION. THE CLOUD CEILING
SHOULD SCATTER OUT TUE EVNG.
SPECIFICS FOR KSTL...SWLY SFC WINDS WILL VEER AROUND TO A W-NWLY
DIRECTION BY 09-10Z TUE AFTER FROPA. SHOWERS AND STORMS WILL MOVE
NEWD THROUGH STL LATE TGT. THE CEILING WILL FALL TO AROUND
1000-1500 FT AFTER FROPA. STRONG AND GUSTY NWLY SFC WINDS CAN BE
EXPECTED ON TUE...DIMINISHING TUE NGT AS THE SFC RIDGE AXIS MOVES
THROUGH. THE CEILING HEIGHT WILL GRADUALLY RISE DURING THE DAY ON
TUE...EVENTUALLY SCATTERING OUT BY EARLY TUE EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
103 AM EST TUE JAN 17 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE TO SOUTHERN MICHIGAN BY TUESDAY MORNING,
THEN CONTINUE TRACKING NORTHEAST INTO SOUTHEASTERN CANADA BY THE
AFTERNOON. THIS SYSTEM WILL BRING A LIGHT WINTRY MIX TO THE
REGION OVERNIGHT...INCLUDING SOME FREEZING RAIN. THE MIXED
PRECIPITATION WILL CHANGE OVER TO RAIN TUESDAY MORNING AS WARMER
AIR WORKS INTO THE AREA. A STRONG COLD FRONT WILL SWEEP THROUGH
TUESDAY EVENING...WITH GUSTY NORTHWEST WINDS THAT WILL PERSIST
INTO WEDNESDAY MORNING. LAKE EFFECT SNOW IS LIKELY SOUTHEAST OF
LAKE ONTARIO LATE TUESDAY NIGHT THROUGH EARLY WEDNESDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATE AS OF 1030 PM...JUST TWEAKED POPS...TEMPS TO REFLECT ON-
GOING RADAR TRENDS. SECOND WAVE OF PRECIP WAS RAPIDLY DEVELOPING
AND TRACKING TO THE EAST AND SHUD OVERSPREAD ALL OF THE REGION BY
6Z. 00Z NAM SUGGESTS PRECIP TYPE SHUD REMAIN MAINLY SNOW ACRS NC
NY...UNTIL 9Z OR SO...AND A MIX OF ZR/IP REST OF NE PA AND SC NY
EXCEPT ALONG THE LAKE ONTARIO PLAIN WHERE DOWNSLOPING SHUD KEEP
SFC TEMPS ABV FREEZING DESPITE EVAP COOLING. THE PRECIP WILL BE
LIGHT SO NOT EXPECTING MUCH SNOW IN NC NY...1 TO 3 INCHES AT
BEST. REST OF AREA...LIGHT ICING MAINLY.
PREVIOUS DSCN BELOW...
RADAR SHOWS PRECIPITATION RAPIDLY DEVELOPING ACROSS NEW YORK AND
PENNSYLVANIA IN RESPONSE TO DEEP LAYER ISENTROPIC LIFT. CROSS-
SECTIONS REVEAL A LAYER ALMOST 400 MB THICK OF ISEN LIFT MAINLY
BTWN 900 AND 500 MB. LOOKING AT THE BIG PICTURE...THERE APPEARS TO
BE AT LEAST TWO WAVES OF PRECIPITATION INITIALLY. THE FIRST IS
DEVELOPING PRECIPITATION QUICKLY ACROSS EASTERN NY...WITH THE NEXT
ONE QUICKLY WORKING INTO WRN PA/SW NY ATTM. THE WAVE IN WRN PA/WRN
NY WILL LEAD TO WIDESPREAD LIGHT PRECIPITATION ACROSS ALL OF C NY
AND NE PA BTWN 3 AND 6Z THIS EVENING. IN THE GRIDS...I BASICALLY
EXTRAPOLATED UP TO CAT POPS FROM 30-40 POPS BY 6Z ACROSS ENTIRE
CWA.
AS FOR P-TYPE...I USED A 50-50 BLEND OF THE GFS AND NAM THICKNESS
TOOL IN GFE WHICH CAPTURES THE CHANGEOVER VERY WELL. THIS WAS USED
ON PREVIOUS SHIFT AND IT STILL LOOKS VERY MUCH ON TRACK. BIGGEST
QUESTION IS HOW MUCH SNOW WILL FALL ACROSS THE NERN PART OF
CWA AS 18Z NAM...18Z GFS...18Z LOCAL WRF AND LATEST RUC ALL
INDICATE FROM 1-3 INCHES OF SNOW AT KRME. GIVEN THE COLDER TEMP
PROFILES AND THE RAPIDLY DEVELOPING PRECIPITATION ATTM...THIS
LOOKS GOOD. REST OF AREA LESS THAN 1 INCH OF SNOW AND SLEET. SINCE
QPF AMNTS ARE NOT THAT HIGH I DON/T EXPECT MUCH MORE THAN A SMALL
COATING OF ICE IN CWA...HIGHEST WILL BE CATSKILLS TO UPR MOHAWK
VALLEY WHERE MAYBE .1 TO .2 INCHES OF ICE ACCUMS. EVEN THOUGH TEMPS ARE
ABV FREEZING IN PARTS OF THE CENTRAL SRN TIER/FINGER
LAKES...DEW POINTS ARE LOW ENUF THAT EVAP COOLING FROM PRECIPITATION
SHUD DROP TEMPS TO BELOW FREEZING. THIS OCCURRED IN PA THIS EVE AND
I SEE NO REASON WHY IT WON/T HAPPEN IN THE FINGER LAKES IN THE
NEXT COUPLE HOURS.
DECIDED TO HAVE ADVY IN EFFECT ALL AREAS AT 7 PM...AND WILL DROP
THE FINGER LAKES AREA BY ARND 3 AM...AS I BELIEVE FZRA WON/T LAST
THAT LONG. I ALSO BROKE OUT ONEIDA CO INTO ANTHR WSWSEGMENT TO HIT
THE SNOW A LITTLE HARDER. I ALSO ADDED SOME PATCHY FOG INTO THE
GRIDS ONCE THE SFC TEMPS GET CLSE TO AND ABV FRZG.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
TUESDAY...AREA WILL RESIDE IN WARM SECTOR, AS SFC LOW PRES TRACKS
THROUGH NEARBY SOUTHERN ONTARIO CHANGING ALL REMAINING MIXED
PRECIP OVER ERN/NRN SECTIONS TO JUST RAIN BY MID MORNING. LIGHT
RAIN WILL CONTINUE THROUGH THE DAYTIME PERIOD WITH COVERAGE
GENERALLY DECREASING BY LATE AFTERNOON.
TUESDAY NIGHT...A STRONG COLD FRONT MOVES THROUGH THE AREA BETWEEN
00Z-06Z. MODEL SOUNDINGS AND ISALLOBARIC RISE/FALL COUPLET
INDICATE THE POTENTIAL FOR FREQUENT WINDS GUSTS AROUND 40 MPH,
ESPECIALLY ALONG THE LAKE PLAIN AND IN THE WESTERN CATSKILLS. A
WIND ADVISORY MAY BE NEEDED BY LATER SHIFTS. SCATTERED RAIN
SHOWERS WILL CHANGE TO SNOW SHOWERS IMMEDIATELY BEHIND FRONT IN
STRONG CAA. AFTER 09Z, LES PARAMETERS BECOME FAVORABLE UNDER 280
FLOW. WILL CONTINUE WITH CAT POPS ACROSS ONEIDA COUNTY TOWARD
MORNING.
WEDNESDAY...LOW LEVEL FLOW VEERS TO AROUND 300 DEGREES BY 15Z WITH
T85 AROUND -16C. WENT WITH CAT POPS ACROSS ONONDAGA/MADISON/
ONEIDA COUNTIES WITH POPS LOWERING INTO THE CHC CATEGORY BY MID
AFTERNOON AS SYNOPTIC MOISTURE DECREASES ALONG WITH SFC RIDGING.
WITH FAVORABLE LES CONDITIONS FOR 12 HOURS ACCUMS WILL LIKELY
REQUIRE AN ADVISORY. (3-7 INCHES).
TEMPS ON WEDNESDAY WILL ONLY RISE A FEW DEGREES UNDER GOOD LOW
LEVEL CAA. MAXES WILL RANGE IN THE 20S.
WEDNESDAY NIGHT...SFC HIGH PRES WILL RESIDE OVER THE AREA WITH
MAINLY CLEAR TO PARTLY CLOUDY SKIES. LOW TEMPS WILL RANGE AROUND
ZERO IN THE EAST/NORTH TO THE TEENS PARTS WEST.
THURSDAY...SFC LOW PRES MOVING THROUGH THE UPPER GREAT LAKES ALONG
WITH A DECENT MID LEVEL TROF MAY SPREAD SNOW SHOWERS OVER THE
REGION DURING THE AFTERNOON. POPS WILL BE HIGHER WEST. MAXES WILL
RANGE IN THE MID 20S TO AROUND 30.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNSETTLED WEATHER WITH LOW AMPLITUDE NEAR ZONAL FLOW. NO BIG STORMS
EXPECTED WITH TEMPERATURES AT OR ABOVE NORMAL. THURSDAY NIGHT A COLD
FRONT GOES THROUGH. THIS TIME ALL PRECIPITATION WILL BE SNOW WITH
THE COLD AIR ENTRENCHED OVER THE NE US WITH THE UPPER LEVEL TROF.
FRIDAY ANOTHER BRIEF PERIOD OF LAKE EFFECT BEFORE HIGH PRESSURE
MOVES IN LATE FRIDAY AND FRIDAY EVENING. ANOTHER QUICK STORM MOVES
EAST NORTHEAST FROM THE SOUTHERN MISSISSIPPI VALLEY TO THE MID
ATLANTIC STATES SATURDAY THEN OFF THE NEW ENGLAND COAST SUNDAY. FOR
NOW THIS DOES NOT LOOK LIKE A BIG STORM...AND ONLY BRUSHES THE AREA
WITH LIGHT SNOW. FOR SUNDAY TO MONDAY WARM AIR ADVECTION AHEAD OF A
STRONG COLD FRONT IN THE PLAINS AND DEEP UPPER LEVEL TROF OVER THE
ROCKIES. WE COULD HAVE SOME WEAK LIGHT OVERRUNNING MIXED
PRECIPITATION WITH NUMEROUS SHORT WAVES AND WARM FRONTS LIFTING
NORTHEAST BUT FOR THE MOST PART SHOULD REMAIN DRY AND MILD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
A WARM FRONT HAS BROUGHT PRECIPITATION TO THE AREA TONIGHT. WITH
COLD AIR AT THE SURFACE, A WIDE VARIETY OF PRECIPITATION TYPES HAS
BEEN OBSERVED TONIGHT. THEY HAVE INCLUDED SNOW, FREEZING RAIN, TO
JUST PLAIN RAIN. AS THE SURFACE COLD AIR IS SLOWLY PUSHED OUT, THE
PRECIP TYPE WILL EVENTUALLY CHANGE OVER TO ALL RAIN LATER THIS
MORNING. ALL ACCUMULATIONS ARE EXPECTED TO BE LIGHT. THE MAIN
BATCH OF PRECIPITATION HAS MOVED THROUGH MOST OF THE FORECAST AREA
AND ONLY SCATTERED SHOWERS ARE EXPECTED UNTIL LATE MORNING, WHEN A
MORE STEADY AREA OF ALL RAIN IS EXPECTED TO MOVE THROUGH.
CURRENTLY, THIS IS REFLECTED AS A TEMPO GROUP AS IT SHOULD NOT BE
A LONG LASTING EVENT. LATER THIS EVENING, A COLD FRONT WILL MOVE
THROUGH LATER TODAY AND WINDS WILL BECOME STRONG AND VERY GUSTY
THIS EVENING, WITH SOME GUSTS POSSIBLY EXCEEDING 40KTS IN
LOCALIZED AREAS.
HOWEVER, WINDS THIS MORNING WILL BE GENERALLY SOUTHERLY BETWEEN 5
AND 10 KTS TO LIGHT AND VARIABLE.
.OUTLOOK...
TUESDAY NIGHT TO WEDNESDAY...MVFR/IFR RESTRICTIONS IN RAIN SHOWERS
CHANGING TO SNOW SHOWERS. ALSO...STRONG NORTHWEST WINDS WITH
GUSTS REACHING AT LEAST 25-35 KTS.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR BUT SOME SNOW SHOWERS AND MVFR
POSSIBLE IN NY. IMPROVING TO VFR EVERYWHERE THU AFTN.
THU NGT TO FRIDAY...MVFR. LIGHT SNOW CHANGING TO LAKE EFFECT SNOW
IN NY.
SATURDAY...MVFR IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
PAZ038>040-043-044-047-048-072.
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NYZ009-024-036-037-044>046-055>057-062.
WINTER WEATHER ADVISORY UNTIL 3 AM EST EARLY THIS MORNING FOR
NYZ017-018-022-023-025.
&&
$$
SYNOPSIS...DJN/RRM
NEAR TERM...DJN
SHORT TERM...RRM
LONG TERM...TAC
AVIATION...SLI
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1231 AM EST TUE JAN 17 2012
.SYNOPSIS...
LOW PRESSURE DEVELOPING OVER THE MIDWEST WILL STRENGTHEN AS IT
LIFTS NORTHEAST ACROSS THE LOWER GREAT LAKES AND UP THE ST
LAWRENCE VALLEY. A COLD FRONT TRAILING THE LOW WILL SWEEP ACROSS
THE COMMONWEALTH TONIGHT...FOLLOWED BY A SURGE OF COLDER AIR
BEHIND GUSTY WEST-NORTHWEST WINDS. HIGH PRESSURE WILL MOVE INTO
THE REGION LATER WEDNESDAY INTO EARLY THURSDAY.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
THE MAJORITY OF MESO OBS ARE ABV FZG AND THEREFORE HAVE ALLOWED
THE SRN SEGMENT OF THE WINTER WX ADVY TO EXPIRE. HOWEVER FURTHER
NORTH AND EAST...THE LATEST MESO OBS AND RUC 925MB TEMPS ARE STILL
BLW FZG IN THE N-CNTRL/ENDLESS MTNS AND PTNS OF THE MID SUSQ VLY SO
WILL KEEP ADVY IN PLACE FOR THESE LOCATIONS. THE SHALLOW LLVL COLD
AIR WILL SLOWLY RETREAT THROUGH THE EARLY MORNING AS MILDER AIR
STREAMS INTO THE REGION FROM THE SW IN ADVANCE OF DEVELOPING LOW
AND TRAILING COLD FRONT OVR THE MIDWEST.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
TUESDAY WILL FEATURE A LOW OVC WITH PERIODS OF MORNING
RAIN...TAPERING TO SHOWERS IN THE AFTERNOON. FOG WILL BE SHROUDING
THE RIDGES AT ELEVATIONS AOA 1700 FT MSL. MAX TEMPS TUESDAY WILL
RANGE FROM THE LOWER 40S ACROSS THE NORTH...TO THE LOWER 50S IN
THE SOUTH /A HEFTY 10-15F ABOVE NORMAL FOR MID JANUARY/. STORM
TOTAL LIQ EQUIV PRECIP BY TUESDAY EVENING WILL AVERAGE BETWEEN
0.50 AND 0.75 OF AN INCH.
THE QUESTION FOR THIS PERIOD IS WHEN AND WHERE THE TRANSITION FROM
RAIN TO SNOW AND ANY CHANGING PRECIPITATION TYPE IN BETWEEN WILL
OCCUR. THE COLD FRONT FROM THIS STORM WILL ENTER WESTERN
PENNSYLVANIA AROUND 00Z. IT THEN MOVES QUICKLY THROUGH ON FAST WESTERLY
FLOW ALOFT. 8H TEMPS DROP ABOUT 18C AND SFC PRESSURE RISES ABOUT
15MB OVERNIGHT. THE MODEL CONSISTENCY SHOWS THAT THERE SHOULD BE
STRONG WINDS AT AND BEHIND THE FRONT AND CONTINUE TO 18Z
WEDNESDAY. DURING THE 00Z TO 03Z HOURS AS DEWPOINT DEPRESSIONS
REMAIN AROUND 0 AND DEWPOINTS ARE ABOVE FREEZING RAIN WILL
DOMINATE. AS THE COLD AIR MOVES QUICKLY THROUGH THE RAIN WILL
QUICKLY TURN TO SNOW...ALLOWING FOR ONLY A BRIEF PERIOD FOR ANY
MIXED PRECIPITATION. IF AND WHEN THERE IS IT WILL BE A RAIN SNOW
MIX...ESPECIALLY THE HIGHER ELEVATIONS WHICH WILL THEN SWITCH TO
SNOW BY 03Z. THE SPEED OF THE SYSTEM...ALONG WITH INCREASE SHEAR WILL
LIMIT SNOW ACCUMULATIONS. ANY SNOW ACCUMULATIONS WILL OCCUR AT THE
END OF THIS SYSTEM AS THE TROUGH LIFTS OUT AND THE WINDS SHIFT TO
THE NORTHWEST...ALLOWING FOR ONLY LAKE EFFECT AND TOPOGRAPHIC SNOW
SHOWERS....FROM 06Z TO AROUND 18Z. IF THE SNOW SETS UP QUICKLY
WITH LITTLE RAIN MIX...AND WITH -15C AT 850 MB THERE COULD BE A SLIGHT
CHANCE FOR AN ADVISORY IN THE NW MTNS. HOWEVER...SINCE DENDRITIC
GROWTH WILL BE LIMITED AND MOST SNOW GENERATION WILL PROBABLY BE
GRANULES AND COLUMNS ALONG WITH THE HIGH SHEAR AND SHORT DURATION OF
THE BEST FETCH WILL WAIT TO ISSUE ANY HIGHLIGHTS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
COLD AIR WITH PERIODS OF LAKE EFFECT SNOW WILL CONTINUE THROUGH
FRIDAY. TEMPERATURES WILL BE COLD THROUGH FRIDAY...ESPECIALLY AS A
FINGER OF THE JET PROTRUDES THROUGH THE EASTERN GREAT LAKES ON
FRIDAY. WITH WARM AIR ADVECTION NEXT WEEKEND SHOULD SEE WARMER
TEMPERATURES SATURDAY AND SUNDAY. THOUGH THE CURRENT LONG RANGE
MODELS HAVE A WEAK TROUGH PROPAGATING THROUGH...WITH THE EC SHOWING
SLIGHTLY MORE AMPLITUDE...A GREATER NEGATIVE TILT AND SLOWER
PROGRESSION. GFS MOVES THE SYSTEM THROUGH EARLY SATURDAY. THE EC
BRINGING THE SYSTEM THROUGH LATE SATURDAY...EARLY SUNDAY. HOWEVER
THE DICHOTOMY OF THE MODELS REMAINS THAT BY MID SUNDAY THEY ARE ALMOST
180 DEGREES OUT OF EACH OTHER. BASED ON THE CONSENSUS AND RECENT
TRENDS...HAVE BEST PRECIP CHANCES BY MIDDAY SATURDAY...WITH A
POSSIBILITY OF A RAIN SNOW MIX. HAVE BROUGHT UP PRECIP CHANCES ON SUNDAY
SLIGHTLY BUT MAINLY IN THE HIGHER ELEVATIONS. MAINLY DRY
CONDITIONS ELSEWHERE.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
AN APPROACHING LOW PRESSURE SYSTEM WILL BRING INCREASING SSW TO
SWRLY FLOW ALOFT...RESULTING IN LLWS ACROSS MOST OF CENTRAL PA
THRU TUESDAY EVENING.
THIS SYSTEM HAS SPREAD A LIGHT WINTRY MIX ACROSS CENTRAL AND
NORTHERN PA THIS EVENING WITH MAINLY RAIN ACROSS THE SOUTH. ANY
MIXED PRECIP ACROSS THE NORTH WILL TRANSITION TO MAINLY JUST OCNL
LIGHT RAIN AFTER MIDNIGHT. HOWEVER...LATEST MDL DATA SUGGESTS
TEMPS COULD LINGER NR THE FREEZING MARK AT IPT UNTIL ARND 09Z.
ENSEMBLE AND 18Z OPER MDL DATA CONTINUE TO INDICATE THE GREATEST
THREAT OF IFR CONDS TONIGHT WILL BE AT BFD...WHERE MOIST SSW FLOW
ASCENDS THE MTNS. OTHERWISE...MDL DATA SUPPORTS NO WORSE THAN
MVFR CIGS/VSBYS OVERNIGHT.
A PERIOD OF STEADY RAIN ACCOMPANIED BY WIDESPREAD IFR VSBYS/CIGS
IS POSSIBLE BTWN 12Z-18Z...AS LOW PRES CENTER TRACKS WEST OF THE
STATE. LIFTING CIGS/IMPROVING VSBYS LIKELY ACROSS SOUTHERN PA BY
AFTN...AS WARM FRONT LIFTS NORTH INTO THE STATE.
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION TUESDAY EVENING FOLLOWED
BY WESTERLY WINDS GUSTING BETWEEN 30 AND 35KTS TUES NIGHT.
OUTLOOK...
WED...NO SIG WX EXPECTED.
THU...SHSN/REDUCED VSBYS POSS...MAINLY W MTNS.
FRI...NO SIG WX EXPECTED.
SAT...LGT FROZEN PRECIP POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR PAZ006-
012-037-041-042-045-046-049>053-058.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DANGELO/CERU
LONG TERM...CERU/STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
351 AM CST TUE JAN 17 2012
.SHORT TERM...TODAY THROUGH THURSDAY
302 AM CST TUE JAN 17 2012
AT 3 AM...A LOW PRESSURE SYSTEM WAS MOVING NORTHEAST THROUGH
SOUTHERN ILLINOIS. ON THE SOUTH SIDE OF THIS SYSTEM...THERE HAS
BEEN SEVERAL TORNADO WARNINGS OVERNIGHT ACROSS THE SPRINGFIELD
MISSOURI COUNTY WARNING AREA. MEANWHILE TWO AREAS OF SNOW ARE
STARTING TO DEVELOP ACROSS THE UPPER MIDWEST. THE FIRST AREA OF
SNOW IS ASSOCIATED WITH STRONG 900 TO 800 MB FRONTOGENESIS ACROSS
SOUTHERN IOWA. A SECOND AREA OF SNOW IS LOCATED ACROSS SOUTHWEST
MINNESOTA AND NORTHWEST IOWA. THIS SNOW IS ASSOCIATED WITH A
POTENTIAL VORTICITY ANOMALY.
BOTH THE 17.00Z AND 17.06Z MODELS ARE IN VERY GOOD AGREEMENT THAT
A SHORT WAVE TROUGH WILL MOVE THROUGH SOUTHEAST MINNESOTA...
NORTHEAST IOWA...AND WEST CENTRAL AND CENTRAL WISCONSIN THROUGH
EARLY THIS AFTERNOON. THERE IS DEEP OMEGA ASSOCIATED WITH THIS
WAVE WHICH WILL ALLOW THE DRY AIR CURRENTLY LOCATED BETWEEN 5 AND
15K FEET TO QUICKLY SATURATED. WITH THIS SYSTEM SOMEWHAT MOISTURE
STARVED INITIALLY... THINKING ONLY AROUND AN INCH ACROSS SOUTHEAST
MINNESOTA AND MUCH OF NORTHEAST IOWA. FURTHER EAST...THE MOISTURE
IS A BIT MORE PLENTIFUL AND THERE WILL BE AT LEAST 7K FEET OF
DENDRITES. THIS SHOULD RESULT IN 1 TO 2 INCHES ALONG AND NORTH OF
THE INTERSTATE 90 CORRIDOR.
MEANWHILE IN CLAYTON COUNTY IN NORTHEAST IOWA...AND CRAWFORD...
GRANT...AND RICHLAND COUNTIES IN SOUTHWEST WISCONSIN...THE STRONG
POTENTIAL VORTICITY ANOMALY WILL MEET UP WITH STRONG 900 TO 800 MB
FRONTOGENESIS. IN ADDITION...THERE WILL BE AT LEAST 6 HOURS OF AT
LEAST 7K FEET OF DENDRITES. THIS IS ALSO THE AREA WHERE THERE IS
THE BEST MOISTURE /TWO TENTHS TO A QUARTER INCH/. THINKING THAT
THERE WILL BE HIGH PROBABILITY OF 2 TO 4 INCHES OF SNOW ACROSS
THIS AREA. THIS IS IN GOOD AGREEMENT WITH THE 16.21Z SREF DATA. IN
ADDITION...THERE WILL BE NORTHWEST WINDS OF 15 TO 25 MPH. THIS
WILL RESULT IN SOME BLOWING AND DRIFTING SNOW. DUE TO THE
COMBINATION OF SNOW AND WINDS...A WINTER WEATHER ADVISORY HAS BEEN
ISSUED FROM 5 AM THIS MORNING THROUGH 3 PM THIS AFTERNOON.
ON WEDNESDAY AFTERNOON AND EVENING...THE MODELS CONTINUE TO SHOW
THAT ANOTHER STRONG SHORT WAVE TROUGH WILL MOVE SOUTHEAST THROUGH
THE AREA. MUCH OF THE LIFT ASSOCIATED WITH THIS WAVE GOES TOWARD
SATURATING THE VERY DRY AIR AHEAD OF IT. LIKE THE PAST COUPLE OF
DAYS...IT LOOKS LIKE THE BEST PROBABILITIES /ALBEIT SMALL/ FOR
SNOW WILL BE ALONG AND NORTH OF INTERSTATE 94. FURTHER SOUTH...
THERE MAY SOME SNOW FLURRIES DURING THIS TIME PERIOD. WITH THERE
BEING WARM AIR ADVECTION AHEAD OF THIS WAVE...WENT WITH A NON
DIURNAL TEMPERATURE CURVE TO KEEP THE TEMPERATURES WARMER DURING
THE EVENING AND ALSO HANDLE THE POTENTIAL THAT THE HIGH
TEMPERATURE MAY OCCUR DURING THE LATE AFTERNOON OR EARLY EVENING.
ON THURSDAY...STRONG COLD AIR ADVECTION MOVES SOUTHWARD INTO THE
AREA. HOWEVER...IT DOES NOT LOOK QUITE AS COLD AS IT WAS
ADVERTISED TO BE OVER THE WEEKEND. EVEN THOUGH THE TEMPERATURES
MAY BE A BIT WARMER...THE WIND CHILLS DURING THE DAY WILL RANGE
FROM 15 TO 25 BELOW.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
302 AM CST TUE JAN 17 2012
ON THURSDAY NIGHT AND FRIDAY...THE MODELS CONTINUE TO SHOW THAT
ANOTHER STRONG SHORT WAVE WILL MOVE THROUGH THE REGION. THE LAST
FOUR RUNS OF THE GFS HAVE CONSISTENTLY SHOWED THAT THIS SYSTEM WILL
MOVE ALONG THE STRONG BAROCLINIC ZONE AND AFFECT THE FORECAST
AREA FROM LATE THURSDAY NIGHT INTO FRIDAY. IN ADDITION...THE QPF
CONTINUES TO INCREASE IN THIS MODEL. AT THIS TIME...IT LOOKS LIKE
THIS SYSTEM MAY PRODUCE 3 TO 6 INCHES OF SNOW IN THE GFS.
MEANWHILE THE ECMWF CONTINUES TO STRUGGLE ON THE TRACK OF THIS
SYSTEM. SINCE THIS MODEL TENDS TO DO BETTER DURING THIS TIME
FRAME...IT DOES INTRODUCE SOME UNCERTAINTY ON WHERE TO RAISE THE
PRECIPITATION CHANCES AND HOW MUCH SNOW MAY FALL ACROSS THE AREA.
DUE TO THIS...ONLY RAISED THE PRECIPITATION CHANCES BY 10 TO 20
PERCENT.
BEHIND THIS SYSTEM...MANY OF THE MODELS CONTINUE TO SHOW THAT THE
POLAR JET WILL RETREAT BACK TO THE NORTH AS THE ARCTIC OSCILLATION
STARTS TO BECOME MORE POSITIVE. THE GFS IS THE SLOWEST AT THIS
OCCURRING. MEANWHILE THE ECMWF AND GEM ARE THE MOST AGGRESSIVE
WITH THIS PATTERN CHANGE. FOR THE TIME BEING...JUST WENT
CONSERVATIVE AND MADE NO CHANGES TO THE ALL BLEND FOR THE WEEKEND
AND EARLY NEXT WEEK.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1117 PM CST MON JAN 16 2012
THE 17.00Z MODELS HAVE COME INTO BETTER CONSENSUS THAT THE MAIN
SHORT WAVE TROUGH COMING OUT OF THE ROCKIES WILL TAKE A SLIGHTLY
MORE SOUTHERN TRACK. THIS IS NOT EXPECTED TO GO ACROSS NORTHERN
IOWA AND THE WISCONSIN/ILLINOIS BORDER. THIS WILL FOCUS THE BEST
FORCING JUST TO THE SOUTH OF THE TAF SITES BUT THERE STILL APPEARS
TO BE ENOUGH FORCING TO PRODUCE LIGHT SNOW AT BOTH TAF SITES. A
WEAKER SHORT TROUGH FARTHER NORTH IN THE LONG WAVE TROUGH WILL
PRODUCE SOME WEAK LIFT ACROSS THE AREA AS IT COMES THROUGH LATE
TONIGHT AND TUESDAY MORNING BRINGING ABOUT 12 PVU/S OF VORTICITY
ADVECTION IN THE 500-300 MB LAYER. THERE STILL LOOKS TO BE SOME
WEAK FRONTOGENESIS IN THE 850-700 MB LAYER ASSOCIATED WITH THIS
WAVE. THE QG CONVERGENCE WILL BE WEAK BELOW 500 MB BUT BECOMES
QUITE STRONG AROUND 12Z ABOVE 500 MB AS THE TWO WAVE COME ACROSS
THE AREA. ALSO STILL LOOKING AT A BROAD AREA OF ABOUT 2 UBAR/S OF
UPGLIDE ON THE 280K ISENTROPIC SURFACE UNTIL THE LONG WAVE TROUGH
PASSES THROUGH DURING THE AFTERNOON. THE NAM AND 17.03Z RUC BUFKIT
SOUNDINGS SUGGEST THERE WILL BE A DRY MID LEVEL LAYER TO OVERCOME
AND THE 00Z RAOBS FROM KDVN AND KGRB DO CONFIRM THAT THIS IS REAL.
HAVE THUS PUSHED BACK THE STARTING TIME OF THE SNOW A LITTLE AND
THEN BRING THE VISIBILITY DOWN TO IFR AROUND 12Z WHEN ALL THE
FORCING COMES TOGETHER TO PRODUCE ABOUT A 5 TO 6 HOURS OF SOME
DECENT SNOW. ONCE THE FORCING STARTS TO MOVE EAST...THE SNOW
SHOULD QUICKLY END WITH THE VISIBILITY AND CEILINGS RETURNING TO
VFR BY MID TO LATE AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST MON JAN 16 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1131 PM CST MON JAN 16 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
250 PM CST MON JAN 16 2012
FORECAST FOCUS REMAINS THE PCPN CHANCES FOR THE NEXT FEW DAYS...WITH
A QUICK COOL DOWN AT MID WEEK.
16.12Z MODEL RUNS AND THE FORECAST STILL LOOKS ON TRACK WITH THE
PCPN POTENTIAL FOR LATE TONIGHT/TUE. LATEST WATERVAPOR IMAGERY
DEPICTED AN UPPER LEVEL SHORTWAVE TROUGH DRIVING ACROSS THE SOUTHERN
PLAINS...MOVING NORTHEAST...WHILE ANOTHER TROUGH WAS MOVING ACROSS
THE CENTRAL/SOUTHERN ROCKIES. GFS/NAM TAKE THIS INTO SOUTHERN
MICH...WITH THIS FEATURE WORKING ON THE SFC FRONT THAT PASSED ACROSS
THE LOCAL AREA TODAY. INTERACTING WITH LOW LEVEL MOISTURE
TRANSPORT...EXPECT AREAS OF PCPN TO DEVELOP AROUND THE FRONT AND
SHORTWAVE TRACK. MOST SHOULD STAY SOUTH OF THE FORECAST AREA
INITIALLY...BUT MODELS HAVE BEEN BRINGING THE NORTHERN EDGE OF THE
PCPN INTO PORTIONS OF NORTHEAST IA/SOUTHWEST WI TONIGHT. WITH GOOD
ISENTROPIC UPGLIDE IN THIS REGION AND INCREASING LOW LEVEL
SATURATION...THIS LOOKS REASONABLE. HOWEVER...NORTH-SOUTH RUNNING
X-SECTIONS AND BUFKIT SOUNDINGS IN THIS REGION KEEP THE SATURATION
RELATIVELY SHALLOW INITIALLY...AND MORE SUPPORTIVE OF RAIN/FREEZING
RAIN //OR DRIZZLE// RATHER THAN SNOW. ICE GRADUALLY GETS INTRODUCED
INTO CLOUD TOPS OVERNIGHT AS SATURATION DEEPENS WITH THE APPROACH OF
ANOTHER SHORTWAVE TROUGH. WILL KEEP THIS FREEZING PCPN CONFINED TO
THE SOUTH FOR NOW. VERTICAL MOISTURE PROFILES DEEPENS QUICKER NORTH
OF THERE TONIGHT...FAVORING SNOW. THERE COULD BE A COUPLE HOURS
WHERE FREEZING PCPN COULD OCCUR...BUT CONFIDENCE NOT HIGH ENOUGH TO
ADD INTO THE FORECAST AT THIS TIME. STILL...TRENDS WILL HAVE TO BE
MONITORED AND CHANGES MADE IF THIS DOES COME TO FRUITION.
THE NORTH-SOUTH RUNNING GFS/NAM X-SECTIONS SATURATE THE ATMOSPHERE
BETWEEN 09-12Z TUE...AS THAT NEXT SHORTWAVE FROM THE ROCKIES MOVES
INTO MN. DECENT QG CONVERGENCE WITH THIS FEATURE...ESPECIALLY FOR
MN/NORTHERN WI. SHOULD SEE AREAS OF LIGHT SNOW IN RESPONSE TO THE
FORCING AND SATURATION FOR TUES MORNING INTO THE AFTERNOON...EXITING
EAST BY LATE AFTERNOON/EVENING. BUFKIT SOUNDINGS CONTINUE TO SHOW A
DEEP DENDRITIC LAYER FOR A FEW HOURS...BUT THE FORCING ISN/T OVERLY
STRONG NOR IS THE MOISTURE THAT ABUNDANT. PLUS...THIS SYSTEM IS A
QUICK MOVER. SO...SNOW TOTALS SHOULD BE ON THE LOW-SIDE...WITH 1 TO
2 INCHES STILL LOOKING REASONABLE. COBB OUTPUT ALSO SUPPORTS THIS.
ALONG WITH THE PRECIPITATION WILL COME A SHOT OF COLDER AIR. 850 MB
TEMPS ARE PROGGED TO DROP FROM AROUND -2 C AT 00Z TUE TO -14 C AT
00Z WED. STEADY TO PERHAPS SLOWLY FAILING TEMPS ARE EXPECTED FOR
TUES AS A RESULT. TUE HIGHS WILL LIKELY BE AT MIDNIGHT TONIGHT. HIGH
PRESSURE MOVES OVERHEAD FOR WED NIGHT...AND WITH SOME FRESH SNOW
COVER...LOWS WILL BOTTOM OUT IN THE SINGLE DIGITS ABOVE/BELOW ZERO.
16.12Z MODEL RUNS NEXT SLIDE ANOTHER UPPER LEVEL TROUGH ACROSS THE
REGION ON WED/WED EVENING...WITH RUNS IN PREVIOUS DAYS HAVING KEPT
THIS FEATURE A BIT MORE NORTH. NOT A LOT OF MOISTURE WITH THIS
INITIALLY AFTER THE DRIER/COLDER AIR WITH THE AREA OF HIGH
PRESSURE...BUT SOME INDICATION OF AN INCREASE IN LOW SATURATION OUT
AHEAD OF THE SYSTEM/S ASSOCIATED SFC FRONT. THE DEEPER SATURATION
COMES WITH THE TROUGH ITSELF...AND IS STILL PREDOMINATELY ACROSS
MN/NORTHERN WI. FORCING WITH THE SHORTWAVE SHOULD PRODUCE SOME SNOW
FOR THE REGION...WITH MINOR ACCUMULATIONS UP TO AN INCH CURRENTLY
EXPECTED. IF THE LOW SATURATION DEVELOPS AS AGGRESSIVELY AHEAD OF
THE FRONT AS PROGGED BY THE NAM...A SHORT PERIOD OF FREEZING PCPN
WOULD BE POSSIBLE BEFORE FULL SATURATION CHANGES ANY PCPN OVER SNOW.
THE NAM WAS TOO ENTHUSIASTIC ON THE LOW SATURATION LAST NIGHT...AND
FEEL IT MIGHT BE OVERDOING IT AGAIN. WILL LEAN ON THE GFS/EC IN THIS
STEAD.
.LONG TERM...FRIDAY THROUGH MONDAY
250 PM CST MON JAN 16 2012
A SHORTWAVE TROUGH WILL BE PASSING EAST/SOUTHEAST ACROSS THE AREA
EARLY ON FRIDAY WITH THE ECMWF AND GFS EXITING IT EAST IN THE
AFTERNOON...WITH THE GEM LINGERING IT A BIT LONGER. SOME DIFFERENCES
IN POSITIONING TOO...WITH THE EC FARTHEST NORTH...GFS SOUTH...AND
GEM IN THE MIDDLE. STILL...THE SHORTWAVE REMAINS PROGGED TO MOVE
ACROSS THE FORECAST AREA...WITH THE SOUTHERN 1/2 LOOKING MORE LIKELY
FOR ACCUMULATIONS. COULD SEE A FEW INCHES FROM THIS QUICK MOVING
SYSTEM.
SOME DISAGREEMENTS AS WE HEAD INTO THE WEEKEND WITH THE GFS SLIDING
A SHORTWAVE/SFC FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY ON
SAT WHILE THE GEM/EC POINT TO MORE WEAK RIDGING. GOING TO SIDE
TOWARD THE RIDGING/CONSENSUS SOLUTION FOR NOW. IT DOES LOOK WARMER
FOR THE WEEKEND AS A SOUTHERLY FETCH RETURNS.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1117 PM CST MON JAN 16 2012
THE 17.00Z MODELS HAVE COME INTO BETTER CONSENSUS THAT THE MAIN
SHORT WAVE TROUGH COMING OUT OF THE ROCKIES WILL TAKE A SLIGHTLY
MORE SOUTHERN TRACK. THIS IS NOT EXPECTED TO GO ACROSS NORTHERN
IOWA AND THE WISCONSIN/ILLINOIS BORDER. THIS WILL FOCUS THE BEST
FORCING JUST TO THE SOUTH OF THE TAF SITES BUT THERE STILL APPEARS
TO BE ENOUGH FORCING TO PRODUCE LIGHT SNOW AT BOTH TAF SITES. A
WEAKER SHORT TROUGH FARTHER NORTH IN THE LONG WAVE TROUGH WILL
PRODUCE SOME WEAK LIFT ACROSS THE AREA AS IT COMES THROUGH LATE
TONIGHT AND TUESDAY MORNING BRINGING ABOUT 12 PVU/S OF VORTICITY
ADVECTION IN THE 500-300 MB LAYER. THERE STILL LOOKS TO BE SOME
WEAK FRONTOGENESIS IN THE 850-700 MB LAYER ASSOCIATED WITH THIS
WAVE. THE QG CONVERGENCE WILL BE WEAK BELOW 500 MB BUT BECOMES
QUITE STRONG AROUND 12Z ABOVE 500 MB AS THE TWO WAVE COME ACROSS
THE AREA. ALSO STILL LOOKING AT A BROAD AREA OF ABOUT 2 UBAR/S OF
UPGLIDE ON THE 280K ISENTROPIC SURFACE UNTIL THE LONG WAVE TROUGH
PASSES THROUGH DURING THE AFTERNOON. THE NAM AND 17.03Z RUC BUFKIT
SOUNDINGS SUGGEST THERE WILL BE A DRY MID LEVEL LAYER TO OVERCOME
AND THE 00Z RAOBS FROM KDVN AND KGRB DO CONFIRM THAT THIS IS REAL.
HAVE THUS PUSHED BACK THE STARTING TIME OF THE SNOW A LITTLE AND
THEN BRING THE VISIBILITY DOWN TO IFR AROUND 12Z WHEN ALL THE
FORCING COMES TOGETHER TO PRODUCE ABOUT A 5 TO 6 HOURS OF SOME
DECENT SNOW. ONCE THE FORCING STARTS TO MOVE EAST...THE SNOW
SHOULD QUICKLY END WITH THE VISIBILITY AND CEILINGS RETURNING TO
VFR BY MID TO LATE AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST MON JAN 16 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
906 AM CST TUE JAN 17 2012
.DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 15Z...
* LIFR CIGS LIFTING THROUGH IFR INTO MVFR BY LATE MORNING.
* LIGHT RAIN/DRIZZLE CHANGING TO SNOW 15-16Z
* HEAVIEST SNOW AND LOWEST VSBY EXPECTED 16-18Z
* SNOW CONTINUING THROUGH MID AFTERNOON WITH POSSIBLE IFR CIGS AND
LIFR VIS.
* STRONG NORTHWEST WINDS GUSTING UP TO 30 KT FROM LATE MORNING
THROUGH LATE AFTERNOON...POSSIBLY CAUSING BLOWING SNOW.
MDB
//DISCUSSION...UPDATED 15Z...
BAND OF LIGHT TO MODERATE SNOW CONTINUES TO MARCH EASTWARD TOWARDS
THE TERMINALS WITH THE HEAVIEST SNOW EXPECTED AT RFD OVER THE NEXT
FEW HOURS. ORD/DPA/MDW/GYY STILL ABOVE FREEZING AND REPORTING
LIGHT RAIN AND DRIZZLE BUT EXPECT THE TRANSITION TO SNOW TO OCCUR
IN THE 15-16Z HOUR AT THE IL TERMINALS AND A BIT LATER AT GYY.
BAND OF SNOW LOOKS TO CROSS ORD/MDW/DPA AND MAY STAY JUST NORTH OF
GYY. EXPECT VSBY IN SNOW IN THE 1-2SM RANGE WITH 3/4 POSSIBLE AT
TIMES...WITH RFD LIKELY SEEING THE LONGEST DURATION OF LOWEST VSBY.
IFR CIGS WILL IMPROVE TO LOW END MVFR AS COLDER AIR WORKS IN BUT
IFR AND LIFR WILL CONTINUE AT THE CHICAGO METRO AND GARY TERMINALS
FOR A FEW HOURS YET. WINDS STILL ON TRACK TO BECOME MORE
NORTHWESTERLY AND INCREASE IN SPEED INTO MIDDAY.
FROM 12Z...
LOW PRESSURE CURRENTLY CENTERED OVER NORTHEAST INDIANA WILL
CONTINUE TO NEAR TORONTO BY THIS EVENING. COLDER AIR WILL SLOWLY
SPREAD ACROSS THE AREA THIS MORNING AS NORTHERLY WINDS ALSO
STEADILY INCREASE AND BECOME QUITE STRONG BY MID/LATE MORNING.
BULK OF THE RAIN HAS SHIFTED EAST OF THE TERMINALS. STILL A FEW
SHOWERS AND DRIZZLE BUT AS THE COLDER AIR SPREADS ACROSS NORTHWEST
IL...PRECIP WILL BEGIN TO TRANSITION TO SNOW. CHANGEOVER SHOULD
OCCUR RATHER QUICKLY WITH SNOW INTO THE CHICAGO AREA TERMINALS BY
15Z OR SO. COULD BE A BRIEF PERIOD OF SLEET OR FREEZING RAIN...
BUT NOT EXPECTING THIS TO BECOMING PREVAILING. THE HEAVIEST OF THE
SNOW IS EXPECTED TO FALL ACROSS FAR NORTHERN IL INTO SOUTHERN
WI...SO THERE REMAINS SOME UNCERTAINTY AS TO JUST HOW LOW CIGS/VIS
WILL DROP AND HOW MUCH SNOW MAY FALL. IN ADDITION...THE SNOW WILL
LIKELY START SOMEWHAT WET AND STEADILY BECOME DRIER OR FLUFFY AS
SNOW/WATER RATIOS INCREASE. WITH THE GRADIENT TIGHTENING ON THE
BACK SIDE OF THE DEPARTING LOW...WINDS GUSTING 25-30 KTS WILL
LIKELY CAUSE BLOWING AND DRIFTING OF THIS DRIER SNOW...WHEREVER IT
FALLS. THE PERIOD OF TIME OF THE HEAVIEST SNOW WILL LIKELY BE
CENTERED AROUND 18Z WITH SNOW ENDING FROM WEST TO EAST DURING THE
EARLY/MID AFTERNOON HRS. GIVEN THE UNCERTAINTY REGARDING
CIGS/VIS...REFINEMENTS...PERHAPS SIGNIFICANT...WITH LATER UPDATES
SHOULD BE EXPECTED.
MVFR CIGS SHOULD LIFT TO VFR BY EARLY EVENING...AND SCATTER OUT BY
EARLY MORNING. NORTHWEST WINDS WILL REMAIN GUSTY DURING THE
EVENING BUT WILL STEADILY DIMINISH LATE IN THE EVENING INTO THE
OVERNIGHT HOURS AS A RIDGE OF HIGH PRESSURE MOVES ACROSS THE AREA
WEDNESDAY MORNING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 15Z...
* MEDIUM CONFIDENCE REGARDING CIG SPECIFICS BUT HIGH CONFIDENCE IN
TREND.
* HIGH CONFIDENCE LIGHT RAIN/DRIZZLE WILL TRANSITION TO SNOW BY
ABOUT 16Z.
* MEDIUM-HIGH CONFIDENCE IN HEAVIEST SNOW 16-18Z...POSSIBLY A BIT
LONGER.
* HIGH CONFIDENCE IN LESS INTENSE CONTINUING INTO MID AFTERNOON
BUT LOW CONFIDENCE IN END TIME.
* MEDIUM-HIGH CONFIDENCE REGARDING WIND SPEEDS/GUSTS/DURATION.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF SNOW. GUSTY SOUTHWEST WINDS
SHIFTING WESTERLY BY MORNING.
* THURSDAY...SLIGHT CHANCE OF SNOW EARLY. GUSTY NORTHWEST WINDS.
* FRIDAY...SNOW. IFR CIGS. LIFR VIS.
* SATURDAY...VFR.
* SUNDAY...VFR. SLIGHT CHANCE OF RAIN LATE.
* MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. CMS
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
TUESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
601 AM CST TUE JAN 17 2012
.DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* LIFR CIGS LIFTING THROUGH IFR INTO MVFR BY LATE MORNING.
* LIGHT RAIN/DRIZZLE CHANGING TO SNOW BY MID/LATE MORNING.
* SNOW CONTINUING THROUGH MID AFTERNOON WITH POSSIBLE IFR CIGS AND
LIFR VIS.
* STRONG NORTHWEST WINDS GUSTING UP TO 30 KT FROM MID/LATE MORNING
THROUGH LATE AFTERNOON...POSSIBLY CAUSING BLOWING SNOW. CMS
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE CURRENTLY CENTERED OVER NORTHEAST INDIANA WILL
CONTINUE TO NEAR TORONTO BY THIS EVENING. COLDER AIR WILL SLOWLY
SPREAD ACROSS THE AREA THIS MORNING AS NORTHERLY WINDS ALSO
STEADILY INCREASE AND BECOME QUITE STRONG BY MID/LATE MORNING.
BULK OF THE RAIN HAS SHIFTED EAST OF THE TERMINALS. STILL A FEW
SHOWERS AND DRIZZLE BUT AS THE COLDER AIR SPREADS ACROSS NORTHWEST
IL...PRECIP WILL BEGIN TO TRANSITION TO SNOW. CHANGEOVER SHOULD
OCCUR RATHER QUICKLY WITH SNOW INTO THE CHICAGO AREA TERMINALS BY
15Z OR SO. COULD BE A BRIEF PERIOD OF SLEET OR FREEZING RAIN...
BUT NOT EXPECTING THIS TO BECOMING PREVAILING. THE HEAVIEST OF THE
SNOW IS EXPECTED TO FALL ACROSS FAR NORTHERN IL INTO SOUTHERN
WI...SO THERE REMAINS SOME UNCERTAINTY AS TO JUST HOW LOW CIGS/VIS
WILL DROP AND HOW MUCH SNOW MAY FALL. IN ADDITION...THE SNOW WILL
LIKELY START SOMEWHAT WET AND STEADILY BECOME DRIER OR FLUFFY AS
SNOW/WATER RATIOS INCREASE. WITH THE GRADIENT TIGHTENING ON THE
BACK SIDE OF THE DEPARTING LOW...WINDS GUSTING 25-30 KTS WILL
LIKELY CAUSE BLOWING AND DRIFTING OF THIS DRIER SNOW...WHEREVER IT
FALLS. THE PERIOD OF TIME OF THE HEAVIEST SNOW WILL LIKELY BE
CENTERED AROUND 18Z WITH SNOW ENDING FROM WEST TO EAST DURING THE
EARLY/MID AFTERNOON HRS. GIVEN THE UNCERTAINTY REGARDING
CIGS/VIS...REFINEMENTS...PERHAPS SIGNIFICANT...WITH LATER UPDATES
SHOULD BE EXPECTED.
MVFR CIGS SHOULD LIFT TO VFR BY EARLY EVENING...AND SCATTER OUT BY
EARLY MORNING. NORTHWEST WINDS WILL REMAIN GUSTY DURING THE
EVENING BUT WILL STEADILY DIMINISH LATE IN THE EVENING INTO THE
OVERNIGHT HOURS AS A RIDGE OF HIGH PRESSURE MOVES ACROSS THE AREA
WEDNESDAY MORNING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE REGARDING CIG TRENDS.
* HIGH CONFIDENCE LIGHT RAIN/DRIZZLE WILL TRANSITION TO SNOW BY
MID/LATE MORNING.
* HIGH CONFIDENCE REGARDING SNOW LATER THIS MORNING INTO THIS
AFTERNOON...LOW CONFIDENCE REGARDING SPECIFICS ON TIMING...
VIS/CIGS AND AMOUNTS.
* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS/DURATION. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF SNOW. GUSTY SOUTHWEST WINDS
SHIFTING WESTERLY BY MORNING.
* THURSDAY...SLIGHT CHANCE OF SNOW EARLY. GUSTY NORTHWEST WINDS.
* FRIDAY...SNOW. IFR CIGS. LIFR VIS.
* SATURDAY...VFR.
* SUNDAY...VFR. SLIGHT CHANCE OF RAIN LATE.
* MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. CMS
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
TUESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM TUESDAY TO 10 PM
TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...9 AM TUESDAY TO
NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
408 AM CST TUE JAN 17 2012
.DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 10Z...
* LIFR CIGS LIFTING TO IFR BY MID MORNING AND MVFR BY LATE
MORNING.
* LIGHT RAIN/DRIZZLE CHANGING TO SNOW MID/LATE MORNING WITH SNOW
CONTINUING INTO THIS AFTERNOON.
* NORTHWEST WINDS GUSTING TO NEAR 30 KTS FROM LATE MORNING THROUGH
LATE AFTERNOON. CMS
//DISCUSSION...UPDATED 06Z...
THE SURFACE FRONT CONTINUES DRAPED FROM WESTERN IL THROUGH CHICAGO
INTO LOWER MI. LOW PRESSURE IS EVOLVING NORTHEAST ALONG THIS
FEATURE THROUGH THE EARLY MORNING. EARLIER SHOWERS HAVE
DECREASED IN COVERAGE...HOWEVER A RE-INCREASE IN SHOWER COVERAGE
IS EXPECTED BY 09Z. SOME OF THE SHOWERS MAY PUT DOWN BRIEF
MODERATE TO HEAVY RAIN. SOME THUNDER IS POSSIBLE ACROSS THE
SOUTHERN GATES AND HAS ALREADY BEEN OBSERVED JUST NORTH OF KLAF.
SURFACE TEMPERATURES WILL REMAIN ABOVE FREEZING THROUGH 12Z WITH
HIGH CONFIDENCE...SO DO NOT EXPECT ANY FREEZING PRECIPITATION. AS
THE LOW MOVES TO THE IMMEDIATE EAST OF THE AREA BY MID
MORNING...THE ATMOSPHERIC TEMPERATURES WILL COOL SIGNIFICANTLY
FAVORING PRECIPITATION TYPE TO BE SNOW. A BRIEF MIX MAY OCCUR AT
THE LEADING EDGE OF THIS TRANSITION. WITH THE ARRIVAL OF THE SNOW
WILL ALSO COME THE ONSET OF STRONG NORTHWEST WINDS. GUSTS TO NEAR
30 KTS ARE HIGHLY LIKELY...AND THE COMBINATION OF THAT AND FALLING
SNOW WILL LIKELY LEAD TO REDUCED VISIBILITY TO 1SM OR EVEN LOWER
FOR A WHILE NEAR MIDDAY. WHILE THE CEILINGS WILL IMPROVE SLOWLY
DURING THE AFTERNOON...THE SNOW SHOULD LAST UNTIL 21Z-23Z OR SO
BEFORE ENDING. SCATTERING IS LIKELY DURING THE EVENING. MTF
//ORD AND MDW CONFIDENCE...UPDATED 10Z...
* HIGH CONFIDENCE REGARDING CIGS THROUGH MID MORNING...LOW
CONFIDENCE FROM LATE MORNING INTO THIS AFTERNOON.
* HIGH CONFIDENCE LIGHT RAIN/DRIZZLE WILL CONTINUE THROUGH MID
MORNING...THEN CHANGE TO SNOW.
* HIGH CONFIDENCE REGARDING SNOW LATER THIS MORNING INTO THIS
AFTERNOON...LOW CONFIDENCE REGARDING SPECIFICS ON TIMING...
VIS/CIGS AND AMOUNTS.
* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS/DURATION. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR. MVFR AND GUSTY WEST NORTHWEST WINDS DEVELOPING
DURING THE NIGHT.
THURSDAY...MVFR POSSIBLE. GUSTY NORTHWEST WINDS.
FRIDAY...MVFR...WITH IFR POSSIBLE. CHANCE OF SNOW.
SATURDAY...SLIGHT CHANCE OF RAIN/SNOW.
SUNDAY...SLIGHT CHANCE OF RAIN OR SNOW DURING THE NIGHT.
MTF
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM TUESDAY TO 10 PM
TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...9 AM TUESDAY TO
NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
943 AM EST TUE JAN 17 2012
LATEST UPDATE...SYNOPSIS/SHORT TERM...
.SYNOPSIS...(943 AM EST TUE JAN 17 2012)
LOW PRESSURE WILL BRING RAIN CHANGING TO FREEZING DRIZZLE AND THEN
SNOW TODAY. FROM 2 TO 6 INCHES OF SNOW IS EXPECTED NORTH OF
INTERSTATE 96 BY MIDNIGHT. THE EVENING COMMUTE COULD BE SLOWED BY
ICY ROADS AS TEMPERATURES DROP BELOW FREEZING THIS AFTERNOON. LAKE
EFFECT SNOW SHOWERS ARE EXPECTED OVERNIGHT AS ARCTIC AIR MOVES IN
WITH 1 TO 4 INCHES OF ADDITIONAL SNOW ALONG AND WEST OF HIGHWAY 131
BY WEDNESDAY MORNING.
&&
.SHORT TERM...(943 AM EST TUE JAN 17 2012)
(THIS AFTERNOON THROUGH THURSDAY AFTERNOON)
DROPPED THE DENSE FOG ADVISORY AS RAIN EARLIER THIS MORNING HAS
ALLOWED VISBYS TO IMPROVE. INCREASING NORTHEAST WINDS SHOULD KEEP
DENSE FOG FROM REFORMING. DROPPED MENTION OF THUNDER AS SOUTHERN
FORECAST AREA IS CURRENTLY DRY SLOTTED AND HRRR RUC SHOWS ANY
CONVECTIVE LOOKING PRECIP FORMING OFF TO THE EAST OF THE SOUTHERN
FORECAST AREA.
WILL HAVE TO CONSIDER EXPANDING THE WINTER WEATHER ADVISORY
SOUTHWARD THIS AFTERNOON AS TEMPS FALL BELOW FREEZING ALLOWING
RESIDUAL MOISTURE TO FREEZE ON ROADS...COMBINED WITH SYNOPTIC SNOWS
AND PERHAPS A PERIOD OF FREEZING RAIN OR DRIZZLE.
REST OF PREVIOUS DISCUSSION FOLLOWS.
THE LOW PRESSURE SYSTEM RESPONSIBLE FOR THIS WILL TRACK FROM NEAR
SBN AT 12Z THIS MORNING TO LAKE ONTARIO BY 00Z THIS EVE. PCPN TYPE
TODAY SHOULD BE ALL SNOW ACROSS OUR NORTHERN COUNTIES WHERE SNOW
ACCUMULATIONS OF 3 TO 6 INCHES ARE ANTICIPATED. ACROSS OUR CENTRAL
COUNTIES WE EXPECT LIGHT RAIN/DRIZZLE TO GRADUALLY TRANSITION TO
SNOW TOWARD MID TO LATE MORNING. 1 TO 3 INCHES OF SNOW IS THE MOST
LIKELY OUTCOME ACROSS THIS AREA... MAYBE LOCALLY 4 INCHES WHERE
P-TYPE TRANSITIONS TO SNOW THE SOONEST.
P-TYPE WILL GRADUALLY TRANSITION FROM RAIN TO SNOW ACROSS OUR
SOUTHERN COUNTIES FROM WNW TO ESE THIS AFTN AS SUGGESTED BY 00Z
GFS/NAM LOW LEVEL THICKNESS TOOLS. ONLY A FEW TENTHS TO AS MUCH AS 2
INCHES OF SNOW WILL FALL ACROSS OUR SOUTHERN COUNTIES THIS AFTN...
WITH LOWEST AMOUNTS OF LESS THAN AN INCH NEAR JXN... WHERE P-TYPE
WON/T CHANGE TO SNOW UNTIL MID TO LATE AFTN.
NW FLOW LES WILL DEVELOP LATE THIS AFTN/EVE AS H8 TEMPS FALL
SIGNIFICANTLY TO -16 TO -18 C BY 06Z WED. A QUICK ADDITIONAL 1 TO 4
INCHES OF LES IS ANTICIPATED FROM 00Z THRU 06Z THIS EVE... MAINLY IN
THE FAVORED NW FLOW SNOW BELT AREAS NEAR TO WEST OF US-131. THE AREA
NEAR TO SW OF A LINE FROM MKG TO AZO WILL BE FAVORED FOR LES THIS
EVE. HOWEVER LOWERING INVERSION HEIGHTS AND SFC RIDGING WILL CAUSE
SNOW SHOWERS TO ALREADY BEGIN TO WIND DOWN SLOWLY AFTER 06Z.
A HIGH PRESSURE RIDGE WILL BRING FAIR WX WEDNESDAY BEFORE SNOW
DEVELOPS WEDNESDAY NIGHT AS THE NEXT LOW PRESSURE SYSTEM AND COLD
FRONT MOVES THROUGH FROM 06Z THRU 12Z THUR. STRONG NW FLOW CAA
THURSDAY MEANS THAT TEMPS AROUND DAYBREAK WILL ONLY BE IN THE UPPER
TEENS TO LOWER 20S... WITH SLOWLY FALLING TEMPS THROUGH THE TEENS
THROUGH THE DAY. WNW LES IS ANTICIPATED THURSDAY AS H8 TEMPS PLUMMET
TO -19 TO -21 C BY 00Z FRI. SEVERAL ADDITIONAL INCHES OF SNOW ARE
ANTICIPATED THURSDAY IN FAVORED WNW FLOW SNOW BELT AREAS NEAR TO
WEST OF US-131.
&&
.LONG TERM...(400 AM EST TUE JAN 17 2012)
(THURSDAY NIGHT THROUGH MONDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE RISK FOR
ACCUMULATING SNOW FRIDAY.
MODELS ARE NOT IN VERY GOOD AGREEMENT. A WEAK MID LEVEL SHORTWAVE
WILL BE DROPPING SOUTHEASTWARD INTO THE GREAT LAKES REGION FOR
FRIDAY. AT THE SURFACE THE HIGH RES EURO KEEPS THE SURFACE LOW FAR
SOUTH OF MI. THE GFS AND NAM ARE SUPPORTING A TRACK FURTHER NORTH.
THIS MORE NORTHERN TRACK WOULD LEAD TO A BAND OF ACCUMULATING SNOW
IN SOUTHWEST MI. THE AIR IS PLENTY COLD ENOUGH TO SUPPORT LAKE
ENHANCEMENT. WILL BUMP UP POPS TO LIKELY FOR WESTERN PARTS OF MY
FORECAST AREA GIVEN THE POTENTIAL FOR SOME LAKE ENHANCEMENT.
OVERALL THE POTENTIAL FOR AN EXTENDED WARMUP IS DIMINISHING. TRENDS
SHOW THE COLDER AIR HOLDING IN PLACE LONGER. FOR THIS REASON WE
LOWERED TEMPERATURES.
&&
.AVIATION...(700 AM EST TUE JAN 17 2012)
LATEST DATA SUGGESTS A RISK FOR PL AND FREEZING RAIN FOR A FEW SITES
KGRR AND KLAN. KMKG SHOULD SWITCH FROM RAIN TO SNOW BY 15Z. THE
DENSE FOG IS FORECASTED TO GRADUALLY DISSIPATE AS THE COLDER AIR
MOVES IN FROM THE NORTH. CEILINGS AND VISIBILITY VALUES WILL
IMPROVE THE MOST FOR KAZO KJXN AND KBTL THIS MORNING AS UPSTREAM
VALUES IN NRN INDIANA HAVE TRENDED TOWARD IFR.
A BAND OF SNOW SHOULD IMPACT KMKG AND PERHAPS KGRR THE GREATEST LATE
THIS MORNING INTO THE AFTERNOON. LAKE EFFECT WILL DEVELOP LATE THIS
AFTERNOON AND EVENING AS MUCH COLDER AIR FILTERS IN FROM THE
NORTHWEST. THE LAKE EFFECT WILL DIMINISH TONIGHT MAINLY AFTER 06Z.
&&
.MARINE...(400 AM EST TUE JAN 17 2012)
GALE WARNING IN EFFECT TODAY DUE TO STRONG NW WINDS ON THE BACK SIDE
OF THE DEPARTING LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...(400 AM EST TUE JAN 17 2012)
NO ICE JAMS HAVE BEEN REPORTED. POTENTIAL FOR THEM WILL INCREASE
THIS WEEK AS COLDER AIR MOVES IN... PARTICULARLY BY THURSDAY AND
FRIDAY WHEN HIGH TEMPS WILL ONLY REACH THE 15 TO 20 DEGREE MARK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY CONTINUES IN EFFECT UNTIL 7 PM EST THIS
EVENING FOR MASON LAKE OSCEOLA CLARE OCEANA NEWAYGO MECOSTA
ISABELLA MONTCALM AND GRATIOT COUNTIES.
LM...GALE WARNING ST JOSEPH TO MANISTEE 7 AM TO 11 PM TODAY.
&&
$$
SYNOPSIS: OSTUNO
SHORT TERM: LAURENS/OSTUNO
LONG TERM: MJS
AVIATION: MJS
MARINE: LAURENS
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS ALBANY NY
435 PM EST TUE JAN 17 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS MOVES ALONG
THE SAINT LAWRENCE RIVER VALLEY TONIGHT. THE COLD FRONT TO THE
SYSTEM WILL SWING ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND
OVERNIGHT...WITH SCATTERED SNOW SHOWERS...BLUSTERY...AND COLD
CONDITIONS FOR WEDNESDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN
WEDNESDAY AFTERNOON INTO THURSDAY MORNING...AS A CLIPPER LOW WILL
BRING SOME SCATTERED SHOWERS SHOWERS LATE THURSDAY AFTERNOON THROUGH
THURSDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 4 PM...IT HAS BEEN ANOTHER ACTIVE AND BUSY DAY ACROSS THE
ALY FORECAST AREA. THE NRN TIER HAS HAD MANY LOCATIONS HUNG UP IN
THE UPPER 20S TO NEAR THE FREEZING MARK IN THE THE MID TO LATE
PM...AS THE CURRENT AREA OF PCPN ON THE KENX/NORTHEAST MOSAIC
RADAR HAS PRODUCED PERIODS OF FREEZING RAIN. WE HAD ONE REPORT
COME IN AT 3 PM IN FAIRFIELD OF HERKIMER COUNTY WITH TWO TENTHS OF
AN INCH OF ICE...AND A TEMP OF 31F. THE POTENT LOW PRESSURE SYSTEM
APPROACHING FROM JUST NORTHEAST OF LAKE ERIE THIS HOUR HAS A
DOUBLE WARM FRONT STRUCTURE. THE FIRST WEAK WARM FRONT WENT
THROUGH MOST THE REGION THIS MORNING. A SECOND WARM FRONT OR
THERMAL TROUGH WITH A SHORT-WAVE IN THE SW FLOW HAS FOCUSED THE
AREA OF PCPN. WE WILL BE EXTENDING THE WINTER WEATHER ADVISORY FOR
THE ERN DACKS...LAKE GEORGE-NRN SARATOGA REGION...AND SRN VT
UNTIL 7 PM. WE WILL BE EXPIRING HERKIMER...MONTGOMERY...SRN FULTON
COUNTIES AT 4 PM...AND PHRASE IT AS POCKETS OF FREEZING RAIN...AS
THE LATEST MESONET SITES SHOW TEMPERATURES WARMING ABOVE FREEZING
AT THIS TIME IN THESE SPOTS.
THE OTHER BIG ISSUE TONIGHT IS THE SFC CYCLONE MOVING NORTHEAST
ALONG THE ST LAWRENCE RIVER VALLEY. THE NAM20 INDICATES AN
IMPRESSIVE ISALLOBARIC RISE-FALL PRESSURE COUPLET. WE ARE
EXPECTING 10-12 HPA/3 HRS RISES MOVING NEAR MASSENA WITH THE
DEEPENING AND INTENSIFYING WAVE EARLY THIS EVENING. THE GREATEST PRESSURE
RISES IN OUR AREA ARE 5-6 HPA/3 HRS. WE HAVE EXPANDED THE WIND
ADVISORY TO INCLUDE THE WRN AND SRN DACKS...LAKE GEORGE NRN
SARATOGA REGION...AND SRN VT...AS WELL AS NRN LITCHFIELD CTY CT.
BASICALLY OUR ENTIRE FCST AREA IS IN A WIND ADVISORY BY 10 PM
TONIGHT TO 3 PM TOMORROW...EXCEPT FOR THE MID HUDSON VALLEY /ERN
ULSTER...AND DUTCHESS COUNTIES/...AND SRN LITCHFIELD CTY CT.
THANKS FOR THE COLLABORATION WITH BOX AND OKX FOR THE ADDITION OF
NRN LITCHFIELD CTY. THE H850 WINDS RAMP UP TO 50-70 KTS
TONIGHT...INITIALLY NORTH AND WEST OF KALB PRIOR TO
MIDNIGHT...THEN THEY OVERSPREAD THE REGION. THE 925 HPA WINDS
INCREASE TO 35-50 KTS BTWN 06Z-12Z WITH STRONG COLD AIR ADVECTION
OCCURRING ACROSS THE REGION WITH THE PASSAGE OF THE COLD FRONT.
THE LATEST 18Z NAM40 GUIDANCE HAS H850 TEMPS FALL TO -10C TO -15C
BY 12Z. WE MAY HAVE OUR ACTUAL MAX TEMPS OCCUR AROUND OR SHORTLY
AFTER 12Z TOMORROW.
THERE WILL BE A PERIOD OF UPSLOPE SNOWFALL ALONG THE WRN SPINE OF
THE WRN DACKS...N-CNTRL TACONICS...AND THE SRN GREENS. THE SHOWERS
QUICKLY TRANSITION TO SNOW SHOWERS WITH THE FRONTAL PASSAGE BTWN
03Z-06Z FROM KALB NORTH AND WEST...AND 06Z-09Z SOUTH AND EAST. WE
ARE DEALING WITH A OPEN WAVE...AND THE PERIOD OF OROGRAPHIC
UPSLOPE SNOWFALL SHOULD BE QUICK WITH POSSIBLY 1 TO 4 INCHES
ACROSS THE SRN DACKS/WRN MOHAWK VALLEY...AND 1-2 INCHES OVER THE
SRN GREENS.
WE DID NOT ISSUE ANY LAKE EFFECT/WINTER WX HEADLINES AT THIS TIME.
AGAIN...THE LATEST HIRES WRF...AND HRRR SHOW A NARROW PERIOD WITH
THIS SNOWFALL WITH IT TRANSLATING TO SOME MULTIBANDS TOWARDS
DAYBREAK. WE WILL CONTINUE TO EVALUATE IF ANY HEADLINES ARE
NEEDED...BUT AT THIS TIME THE WINDS LOOK LIKE THE BIGGEST ISSUE.
EXPECT TEMPS TO FALL INTO THE TEENS OVER THE SRN DACKS...AND 20S
OVER MOST OF THE REST OF THE REGION...EXCEPT FOR THE THE MID
HUDSON VALLEY...AND SRN LITCHFIELD CTY WHERE SOME LOWER 30S ARE POSSIBLE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
TOMORROW...THE BUFKIT MOMENTUM TRANSFER PROFILES INDICATE WIND
ADVISORY GUSTS ARE STILL POSSIBLE INTO THE AFTERNOON...ESPECIALLY
IF WE MIX TO 875-900 HPA OR SO. IF WE MIX HIGHER...THEN WE COULD
APPROACH SOME 50 KT GUSTS. OVERALL...NW WIND GUSTS OF 45-55 MPH
ARE POSSIBLE UNTIL ABOUT 20Z. KPOU IS MARGINAL WITH THE GUST
POTENTIAL AROUND 35 KTS OR SO. WE KEPT THAT LOCATION OUT OF THE
WIND ADVISORY. BLUSTERY AND COLD CONDITIONS WILL PERSIST WITH
TEMPS FALLING IN THE 20S AND TEENS IN THE AFTERNOON WITH COLD
ADVECTION CONTINUING WITH H850 TEMPS FALLING TO -15C TO -20C. THE
NW FLOW FAVORS MULTIBANDS OVER CNTRL NY TOMORROW. SOME OF THE
NARROW MULTIBANDS CREEP INTO THE WRN MOHAWK VALLEY...AND ERN
CATSKILLS. A COATING TO AN INCH OR TWO OF SNOW IS POSSIBLE. WE
TENDED TO DECREASE THE POPS TO SLIGHT OR LOW CHC VALUES OVER THE
SRN GREENS...NRN TACONICS...AND BERKSHIRES WITH THE BOUNDARY LAYER
DRYING OUT /WE ARE LOSING THE MOISTURE HERE/ AND THE MESOSCALE
GUIDANCE SHOWING LESS OF AN UPSLOPE EVENT.
IN THE LATE AFTERNOON...THE UPSTREAM SOUNDINGS OVER KYSR...AND
KRME SHOW THE SUBSIDENCE INVERSION LOWERING TO 4-5 KFT AGL
SQUELCHING ANY LAKE EFFECT SNOW.
WEDNESDAY NIGHT...HIGH PRESSURE QUICKLY RIDGES IN OVER NY AND NEW
ENGLAND WITH COLD AND DRY WEATHER. THE WINDS WILL SUBSIDE...AND
EXPECT DECENT RADIATIONAL COOLING WITH LOWS ZERO TO 10 BELOW OVER
THE LAKE GEORGE REGION...AND SOUTHERN ADIRONDACKS...SINGLE DIGITS
ELSEWHERE...EXPECT 10 TO 15F IN THE MID HUDSON VALLEY...AND SRN
LITCHFIELD CTY CT.
THU-THU NIGHT...ANOTHER SYSTEM APPROACHES FROM THE GREAT LAKES
REGION AND SRN ONTARIO FOR LATE THU. MID AND HIGH CLOUDS INCREASE
DURING THE LATE MORNING INTO THE EARLY PM...AS THE WARM ADVECTION
INCREASES. WE PLACE SOME SLIGHT TO LOW CHC POPS IN DURING THE PM
FOR SOME SCT SNOW SHOWERS OR LIGHT SNOW. THE WAVE PASSES WELL
NORTH OVER S-CNTRL QUEBEC...WITH ITS ASSOCIATED WARM AND COLD
FRONTS BRINGING SOME LIGHT SNOW OR SNOW SHOWERS TO REGION WITH
LIGHT SNOW ACCUMULATIONS OF A COATING TO AN INCH OR TWO. WE WENT
WITH THE HIGHEST POPS OVER THE NRN TIER THU NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
NO MAJOR SYSTEMS DURING THIS PERIOD...BUT AREAS OF CHC POPS FOR
MOST. THERE WILL BE WEAK HIGH PRESSURE AREAS INTERSPERSED BETWEEN
WEAK FRONTS/SYSTEMS. A RELATIVELY MODEST WARM-UP IS IN STORE DURING
THE WEEKEND. HIGH TEMPERATURES IN THE TEENS AND 20S ON FRIDAY WILL
BECOME HIGHS FROM THE MID 30S TO LOWER 50S BY MONDAY WHEN 540
1000-500 MB THICKNESSES WILL LIE JUST NORTH OF OUR ZONES. INDEED...
MONDAY WILL BE THE NICEST DAY OF THE PERIOD...WITH THE GREATEST
AMOUNT OF SUNSHINE AND LOWEST POPS. OVERNIGHT LOWS FROM THE MINUS
SINGLE DIGITS IN THE WESTERN ADIRONDACKS...TO THE LOWER 30S IN THE
MID HUDSON VALLEY...WILL MODERATE TO LOWS MOSTLY IN THE 30S SUNDAY
NIGHT AS THERE WILL BE NO REAL DIURNAL COOLING TREND GIVEN THE WARM
FRONT LIFTING THROUGH THE AREA.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
A LARGE BATCH OF RAIN SHOWERS OVER CENTRAL NEW YORK WILL BE MOVING
EASTWARD TOWARDS THE HUDSON VALLEY TAF SITES FOR THE MID TO LATE
AFTN HOURS. TEMPS HAVE WARMED UP ENOUGH IN THE BOUNDARY LAYER FOR
THIS PRECIP TO FALL AS JUST PLAIN RAIN. THIS RAIN WILL ALLOW FOR
WIDESPREAD MVFR CIGS/VSBYS...AND BRIEF PERIODS OF IFR CIGS AND
POSSIBLY VSBYS FOR KALB/KGFL. KPOU SHOULD REMAIN FAR ENOUGH SOUTH
TO AVOID MOST OF THE IFR...BUT MVFR CIGS/VSBYS LOOK LIKELY FOR THE
AFTN/EARLY EVE HOURS THERE AS WELL. SOUTHERLY WINDS WILL BE
GENERALLY FAIRLY LIGHT...LESS THAN 10 KTS.
A COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING. THIS WILL
ALLOW FOR WINDS TO SWITCH TO A SW DIRECTION AND EVENTUALLY
WESTERLY OVERNIGHT. WITH MUCH COLDER AIR MOVING IN ALOFT...BETTER
MIXING WILL OCCUR AND THE LOW CLOUDS WILL SCOUR OUT OVERNIGHT WITH
VFR CIGS/VSBYS RETURNING TO ALL TAF SITES DURING THE LATE EVENING
HOURS. WITH A STRONG AREA OF LOW PRESSURE MOVING THROUGH THE ST.
LAWRENCE VALLEY...VERY STRONG SFC WINDS WILL DEVELOP FOR LATE
TONIGHT AND INTO WEDNESDAY MORNING...MAINLY FOR KALB/KGFL. A FEW
GUSTS MAY APPROACH 40 KTS...ESP IN AREAS OF CHANNELED FLOW /SUCH
AS KALB DUE TO THE MOHAWK VALLEY/...BY WED MORNING. THERE WILL
ONLY FEW-SCT VFR CU ACROSS THE REGION FOR WED MORNING...BUT WINDS
WILL CONTINUE TO BE STRONG RIGHT INTO WED AFTN.
LLWS COULD BE AN ISSUE THIS EVENING AS STRONG WINDS OF AROUND 40
KTS MOVE IN AROUND 2 KFT AFTER 00Z. HOWEVER...SFC WINDS WILL BE
INCREASING...SO LLWS CRITERIA MAY NOT BE OFFICIALLY BE MET.
STILL...WINDS WILL BE INCREASING DURING THE OVERNIGHT HOURS AND
THIS COULD BE ADDRESSED IN FUTURE TAF ISSUANCES.
OUTLOOK...
WED PM...VFR...WINDY.
WED NIGHT...VFR. NO SIG WX.
THU...MAINLY VFR. SLIGHT CHC -SHSN WITH MVFR POSSIBLE.
FRI...VFR. NO SIG WX.
SAT...MVFR/IFR. CHC -SN/-RA.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
THE WEEKEND.
A COLD FRONT WILL MOVE THROUGH THIS EVENING WITH SOME SCATTERED
RAIN AND SNOW SHOWERS WITH LIGHT LIQUID EQUIVALENT AMOUNTS WELL
UNDER A QUARTER OF AN INCH. THE HIGHEST SNOW TALLIES WILL BE ALONG
THE WESTERN SLOPES OF THE SOUTHERN ADIRONDACKS...AND THE SOUTHERN
GREEN MOUNTAINS TUESDAY NIGHT INTO WEDNESDAY WITH SNOWFALL AMOUNTS
OF 1 TO 4 INCHES.
COLD AND DRY WEATHER WILL PREVAIL LATE WEDNESDAY INTO THURSDAY MORNING.
A CLIPPER LOW MAY BRING SCATTERED SNOW SHOWERS OR LIGHT SNOW
THURSDAY NIGHT INTO FRIDAY. ANOTHER SYSTEM FOR THE FIRST HALF OF
THE WEEKEND MAY BRING SOME LIGHT SNOWFALL AGAIN.
ICE FORMATION OR THICKENING WILL SLOW DOWN THROUGH TONIGHT WITH A
BRIEF SPELL OF MILDER WEATHER. ICE FORMATION SHOULD INCREASE AGAIN
WEDNESDAY INTO THURSDAY AS TEMPERATURES FALL BACK WELL BELOW
FREEZING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WIND ADVISORY FROM 10 PM THIS EVENING TO 3 PM EST WEDNESDAY
FOR CTZ001.
NY...WIND ADVISORY FROM 10 PM THIS EVENING TO 3 PM EST WEDNESDAY
FOR NYZ032-033-038>043-047>054-058>061-063-082>084.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ032-033-038>043-082>084.
MA...WIND ADVISORY FROM 10 PM THIS EVENING TO 3 PM EST WEDNESDAY
FOR MAZ001-025.
VT...WIND ADVISORY FROM 10 PM THIS EVENING TO 3 PM EST WEDNESDAY
FOR VTZ013>015.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
VTZ013>015.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...ELH
AVIATION...FRUGIS
HYDROLOGY...WASULA/KL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
244 PM EST TUE JAN 17 2012
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
A COLD FRONT FROM CENTRAL TN THROUGH NORTH MS TO CENTRAL LA WILL
CONTINUE TO APPROACH GA THIS AFTERNOON. AREAS OF SHOWERS AND A FEW
TSTMS ARE MOVING THROUGH NORTH AL AND MOST OF MS AT THIS TIME.
THE AIRMASS OVER GA IN ADVANCE OF THE FRONT REMAINS MARGINALLY
UNSTABLE WITH LIFTED INDICES IN THE ZERO TO MINUS 2 RANGE AND
CAPES OF 300 TO 600 J/KG. MODELS STILL SHOW HIGH SHEAR WITH
HELICITIES IN THE 200 TO 400 RANGE...BUT SEVERE TSTMS ARE
UNLIKELY. SOME BRIEF STRONG WIND GUSTS UP TO 40 MPH WILL BE
POSSIBLE WITH ANY OF THE STRONGER TSTMS. OTHERWISE...WIDESPREAD
SHOWERS WITH ISOLATED TSTMS WILL OCCUR TONIGHT OVER THE FORECAST
AREA.
NAM AND GFS ARE IN GOOD AGREEMENT WITH THE TIMING OF THE COLD FRONT.
IT IS EXPECTED TO ENTER NORTHWEST GA AROUND 7 PM EST THIS EVENING...
PASS OVER THE ATLANTA METRO AREA AROUND 1 AM EST WEDNESDAY...THEN
MOVE EAST THROUGH THE REMAINDER OF THE FORECAST AREA BY 7 AM EST
WEDNESDAY MORNING. COLD HIGH PRESSURE AND DRIER AIR WILL BUILD
OVER GA WEDNESDAY THROUGH THURSDAY WITH TEMPERATURES RETURNING TO
NEAR SEASONAL NORMALS.
HYDROLOGY...
STILL EXPECTING STORM TOTAL RAINFALL AMOUNTS OF ONE HALF TO ONE
INCH ACROSS THE COUNTY WARNING AREA AS GULF MOISTURE...PWS OF 1.3
INCHES...ARE PUMPED INTO THE STATE. ISOLATED HIGHER AMOUNTS POSSIBLE
IN TSTMS. OTHER THAN SOME TEMPORARY ROAD PONDING IN SLOW DRAINING
AREAS...NO FLOODING IS EXPECTED.
16
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
MODELS AGREE ON A BRIEF DRY PERIOD THURSDAY NIGHT. A WEAK SHORT
WAVE MAY AFFECT THE NORTHWEST FRIDAY AND HAVE INCLUDED LOW POPS.
MODELS DIFFER ON LOCATION AND SPEED OF A COUPLE OF SHORT WAVES
THAT DEVELOP DURING THE WEEKEND SO HAVE LEFT CHANCE OR SLIGHT
CHANCE ACROSS THE AREA FOR SATURDAY AND SUNDAY. MORE UNCERTAINTY
FOR MONDAY WITH THE EVOLUTION OF A SOUTHERN STREAM SHORT WAVE...SO
HAVE KEPT CHANCE POPS IN FOR MONDAY.
41
AVIATION...
18Z UPDATE...
AS FIRST LINE OF SHRA HAS PUSHED THROUGH THE TERMINALS...LOW END
MVFR TO HIGH END IFR IS FILTERING IN QUICKLY. WILL CARRY THROUGH
FOR THE REMAINDER OF THE AFTERNOON UNTIL NEXT LINE OF SHRA WITH
EMBEDDED TSRA MOVES IN. LOOKS LIKE THE BEST CHANCES FOR TSRA WILL
BE FOR THE CSG TAF AND KEPT THE TEMPO IN FOR LATER THIS EVENING.
FOR THE REMAINDER OF THE SITES...23Z STILL LOOKS GOOD FOR ATL AREA
TERMINALS ALTHOUGH USING TIMING TOOLS...COULD BE A COUPLE HOURS
EITHER SIDE OF THIS. BASED ON HRRR OUTPUT AND CONSISTENCY
SAKE...JUST KEPT IT AT 23Z FOR NOW. WINDS SHOULD PICK UP OVERNIGHT
AND WILL SEE A QUICK TRANSITION FROM IFR TO MVFR AFTER 09Z. KEPT
MVFR THROUGH 12Z BEFORE SKC BECOMES PREDOMINANT FOR WED. WINDS
WILL BE GUSTY IN THE MORNING BUT SHOULD ACTUALLY DECREASE IN THE
AFTERNOON AS GRADIENT RELAXES.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM IN SHRA/TSRA TIMING.
HIGH FOR REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 44 52 29 57 / 100 5 5 10
ATLANTA 40 52 32 58 / 100 0 5 10
BLAIRSVILLE 34 44 27 51 / 100 0 5 10
CARTERSVILLE 36 48 25 58 / 100 0 5 5
COLUMBUS 44 56 32 61 / 100 5 5 5
GAINESVILLE 38 48 31 53 / 100 5 5 10
MACON 46 56 29 60 / 100 20 5 5
ROME 36 46 27 57 / 100 0 5 5
PEACHTREE CITY 39 51 25 59 / 100 0 5 10
VIDALIA 49 63 32 63 / 90 60 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1254 PM EST TUE JAN 17 2012
.PREV DISCUSSION... /ISSUED 940 AM EST TUE JAN 17 2012/
UPDATE...
A LINE OF SHOWERS WITH LIGHT TO MODERATE RAIN WAS OCCURRING AT THIS
TIME FROM CLARKESVILLE THROUGH CUMMING AND MARIETTA TO CARROLLTON.
THE LINE WAS AROUND 20 MILES WIDE AND MOVING EAST AT 40 MPH. HAVE
INCREASED THE POPS FOR THIS MORNING ACCORDINGLY FOR NORTH AND CENTRAL
GA. THE COLD FRONT OVER THE MS RIVER VALLEY WILL CONTINUE TO
APPROACH THE STATE TONIGHT. STILL LOOKING FOR ADDITIONAL SHOWERS AND
ISOLATED TSTMS TO DEVELOP IN ADVANCE OF THE FRONT LATER THIS
AFTERNOON AND EVENING. MOST MODELS SHOW A HIGH SHEAR BUT LOW
INSTABILITY ENVIRONMENT...SO SEVERE TSTMS IS UNLIKELY FOR GA.
OTHERWISE...NO OTHER CHANGES NEEDED FOR THE FIRST PERIOD.
16
PREV DISCUSSION... /ISSUED 651 AM EST TUE JAN 17 2012/
PREV DISCUSSION... /ISSUED 348 AM EST TUE JAN 17 2012/
SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/...
DEEP LAYER MOISTURE WILL INCREASE ACROSS THE CWA TODAY IN STRONG
SOUTHWESTERLY LOW LEVEL FLOW. THIS SHOULD RESULT IN INCREASING
COVERAGE OF SHOWERS AND A FEW THUNDERSTORMS. INSTABILITY IS
FORECAST TO BE MARGINAL...BUT SHEAR ASSOCIATED WITH STRONG 850MB
JET COULD SUPPORT ISOLATED STRONG THUNDERSTORMS MAINLY THIS
AFTERNOON AND EVENING. SURFACE COLD FRONT SHOULD CROSS THE CWA
TONIGHT WITH ONLY LINGERING SHOWERS EAST CENTRAL WEDNESDAY
MORNING. DRY AND COOL WEDNESDAY NIGHT. WITH WARM ADVECTION
TODAY...WILL FAVOR THE WARMER SIDE OF MAV/MET. OVERNIGHT LOWS ARE
TRICKY DUE TO TIMING OF COLD FRONTAL PASSAGE...BUT NORTHWEST ZONES
SHOULD SEE SOME LOW TO MID 30S BY WEDNESDAY MORNING. AT THIS
POINT...LOOKS LIKE RAIN SHOULD BE ENDING ACROSS THE EXTREME NORTH
BEFORE TEMPERATURES DROP INTO THE 30S.
LONG TERM /THURSDAY THROUGH MONDAY/...
MODELS AGREE ON A BRIEF DRY PERIOD THURSDAY AND THURSDAY NIGHT. A
WEAK SHORT WAVE MAY AFFECT THE NORTHWEST FRIDAY AND HAVE INCLUDED
LOW POPS. MODELS DIFFER ON LOCATION AND SPEED OF A COUPLE OF SHORT
WAVES THAT DEVELOP DURING THE WEEKEND SO HAVE LEFT CHANCE OR
SLIGHT CHANCE ACROSS THE AREA FOR SATURDAY AND SUNDAY. MORE
UNCERTAINTY FOR MONDAY WITH THE EVOLUTION OF A SOUTHERN STREAM
SHORT WAVE...SO HAVE KEPT CHANCE POPS IN FOR MONDAY.
HYDROLOGY...
RAINFALL TOTALS AVERAGING ONE HALF TO ONE INCH ACROSS THE COUNTY
WARNING AREA STILL LOOK REASONABLE. ISOLATED HIGHER AMOUNTS
POSSIBLE IN THUNDERSTORMS. NO FLOODING CONCERNS ARE ANTICIPATED.
&&
.AVIATION...
18Z UPDATE...
AS FIRST LINE OF SHRA HAS PUSHED THROUGH THE TERMINALS...LOW END
MVFR TO HIGH END IFR IS FILTERING IN QUICKLY. WILL CARRY THROUGH
FOR THE REMAINDER OF THE AFTERNOON UNTIL NEXT LINE OF SHRA WITH
EMBEDDED TSRA MOVES IN. LOOKS LIKE THE BEST CHANCES FOR TSRA WILL
BE FOR THE CSG TAF AND KEPT THE TEMPO IN FOR LATER THIS EVENING.
FOR THE REMAINDER OF THE SITES...23Z STILL LOOKS GOOD FOR ATL AREA
TERMINALS ALTHOUGH USING TIMING TOOLS...COULD BE A COUPLE HOURS
EITHER SIDE OF THIS. BASED ON HRRR OUTPUT AND CONSISTENCY
SAKE...JUST KEPT IT AT 23Z FOR NOW. WINDS SHOULD PICK UP OVERNIGHT
AND WILL SEE A QUICK TRANSITION FROM IFR TO MVFR AFTER 09Z. KEPT
MVFR THROUGH 12Z BEFORE SKC BECOMES PREDOMINANT FOR WED. WINDS
WILL BE GUSTY IN THE MORNING BUT SHOULD ACTUALLY DECREASE IN THE
AFTERNOON AS GRADIENT RELAXES.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM IN SHRA/TSRA TIMING.
HIGH FOR REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 62 43 53 28 / 70 80 5 5
ATLANTA 63 38 50 30 / 80 70 5 5
BLAIRSVILLE 58 33 45 25 / 90 60 5 5
CARTERSVILLE 63 35 47 24 / 100 60 5 5
COLUMBUS 68 47 53 30 / 70 80 10 5
GAINESVILLE 60 37 47 30 / 80 70 5 5
MACON 67 48 57 28 / 50 80 10 5
ROME 65 34 47 25 / 100 50 5 5
PEACHTREE CITY 64 37 51 23 / 80 80 5 5
VIDALIA 69 55 61 36 / 40 60 40 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
233 PM CST TUE JAN 17 2012
.DISCUSSION...
1243 PM CST
NO MAJOR CHANGES TO GOING FORECAST BUT HAVE PLAYED DOWN SNOW AMOUNTS
THROUGH THIS EVENING ACROSS NORTHERN ILLINOIS. PRIMARY AREA OF FGEN
FORCING IS NOW MOVING AWAY FROM THE FORECAST AREA WITH RADAR
INDICATING WEAKENING RETURNS. SECONDARY AREA OF SNOWFALL ASSOCIATED
WITH H5 VORT MOVING EAST ACROSS THE RIVER ALSO SHOWING WEAKENING
RETURNS...WITH WFO DAVENPORT REPORTING ONLY A COUPLE TENTHS OVER
LAST 6 HOURS...AND OBSERVER NEAR DBQ COMING IN AT 1.6 INCHES FOR SAME
PERIOD. HAVE HAD SEVERAL REPORTS FROM EARLIER THIS MORNING
SUGGESTING SNOWFALL ALREADY AROUND 3 INCHES ACROSS FAR NORTHWEST
PORTION OF CWA...BUT ONLY EXPECT ADDITIONAL SNOW OF AROUND AN INCH
OVER THESE AREAS...WITH...ON THE HIGH SIDE...PERHAPS LOCALIZED
AMOUNTS AROUND 2 INCHES. MORE REALISTICALLY THOUGH...NEW
ACCUMULATION THROUGH THE REMAINDER OF AFTERNOON WILL LIKELY BE UP
TO AN INCH ACROSS THE NORTH...WITH PERHAPS A DUSTING SOUTH OF THE
I-88 CORRIDOR...AND NO ACCUMULATION SOUTH OF THE I-80 CORRIDOR.
AREAS THAT SEE LIGHT ACCUMULATIONS WILL ALSO HAVE TO DEAL WITH
BLOWING AND DRIFTING SNOW AS WINDS CONTINUE TO GUST AROUND AND
ABOVE 30 MPH THIS AFTERNOON. BMD
//PREV DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SNOW CONTINUING THROUGH THE AFTERNOON...ADDITIONAL DUSTING
TO PERHAPS A FEW TENTHS ACCUMULATION.
* VARIABLE VISIBILITY POSSIBLY AS LOW AS 2SM FOR SHORT PERIODS BUT
MAINLY IN THE 3-6SM RANGE
* SNOW ENDING TOWARD 00-01Z.
* MVFR CIGS WITH VARIABLE BASE HEIGHTS CONTINUING THEN SCATTERING
EARLY EVENING.
* NORTHWEST WINDS GUSTING TO 25-30 KT THRU AFTERNOON...THEN
DIMINISHING THIS EVENING.NOON.
MDB
//DISCUSSION...UPDATED 20Z...
RADAR HAS BEEN SHOWING A DOWNWARD TREND IN REFLECTIVITY INTENSITY
OVER THE LAST HOUR OR SO AS BETTER AREA OF SNOW MOVES ACROSS THE
TERMINALS. LIGHT SNOW WILL CONTINUE BUT VISIBILITY REDUCTION HAS
NOT BEEN AS SIGNIFICANT. EXPECT GENERALLY MVFR VSBY WITH BRIEF
DROPS TO AROUND 1 SM POSSIBLE UNDER BETTER SHOW SHOWERS. SNOW WILL
END FROM WEST TO EAST INTO EARLY EVENING WITH SKIES THEN CLEARING
INTO MID EVENING.
MDB
FROM 18Z...
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST IN TERMS OF
VSBY/SNOWFALL. OVERALL RFD WILL SEE THE MOST PERSISTENT SNOWFALL
AND LOWEST CONDITIONS. LATEST OBSERVED TRENDS SHOW A BIT OF A LULL
IN SNOW INTENSITY AND SOME IMPROVEMENT TO VSBY OCCURRING FROM ORD
BACK TO VYS. SO CHI AREA TERMINALS AND GYY WILL PROBABLY SEE A
BRIEF PERIOD OF IMPROVEMENT NEXT 1-2 HOURS. THE MAIN UPPER TROUGH
IS MOVING EASTWARD ACROSS CENTRAL/EASTERN IOWA WHICH WILL BRING
STEADIER SNOW BACK TO THE AREA THIS AFTERNOON. GENERALLY EXPECT
VSBY AROUND 2SM IN LIGHT SNOW TO RETURN TO THE CHI TERMINALS AND
GYY AND CONTINUE FOR SEVERAL HOURS BEFORE ENDING. MAY SEE SOME
VSBY DOWN TO ABOUT A MILE AS WELL. WITH TEMPERATURES FALLING
ACCUMULATION WILL BECOME MORE LIKELY BUT THE STRONG NORTHWEST
WINDS GUSTING IN THE 25-30 KT RANGE WILL BLOW THE SNOW AROUND.
CIGS SHOULD STAY MVFR BUT BASE HEIGHT WILL LIKELY VARY.
SNOW WILL EXIT TO THE EAST LATE THIS AFTERNOON/EARLY THIS EVENING
AND THE END TIME IN THE TAF MAY NEED TO BE TWEAKED. CIGS LOOK TO
QUICKLY SCATTER/CLEAR EARLY THIS EVENING LEAVING VFR OVERNIGHT
WITH VERY COLD CONDITIONS. HIGH PRESSURE WILL MOVE ACROSS THE AREA
OVERNIGHT AND WEDNESDAY MORNING ALLOWING WINDS TO DIMINISH THIS
EVENING THEN TURN SOUTHWEST AND BECOME LIGHT OVERNIGHT. SPEEDS
WILL INCREASE FROM THE SOUTH-SOUTHWEST THROUGH THE DAY WITH MID
AND HIGH CLOUDS INCREASING DURING THE AFTERNOON AHEAD OF A CLIPPER
SYSTEM MOVING NORTH OF THE AREA.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN LIGHT SNOW CONTINUING THROUGH AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN STEADIER LIGHT SNOW ARRIVING BY MID
AFTERNOON WITH ACCUMULATION POSSIBLE.
* HIGH CONFIDENCE IN VARIABLE VISIBILITY IN LIGHT SNOW AND THAT
ANY VSBY AROUND 2SM WOULD BE BRIEF.
* MEDIUM CONFIDENCE IN SPECIFIC END TIME OF SNOW.
* HIGH CONFIDENCE IN MVFR CIGS CONTINUING INTO EARLY EVENING THEN
SCATTERING.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF SNOW. GUSTY SOUTHWEST WINDS
SHIFTING WESTERLY BY MORNING.
* THURSDAY...SLIGHT CHANCE OF SNOW EARLY. GUSTY NORTHWEST WINDS.
* FRIDAY...SNOW. IFR CIGS. LIFR VIS.
* SATURDAY...VFR.
* SUNDAY...VFR. SLIGHT CHANCE OF RAIN LATE.
* MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. CMS
&&
.MARINE...
231 PM CST
THE VERY PROGRESSIVE PATTERN WILL CONTINUE TO AFFECT LAKE MICHIGAN
FOR THE NEXT SEVERAL DAYS.
NORTH TO NORTHWEST GALES SHOULD PERSIST OVER THE LAKE THROUGH THE
EVENING AS DEEPENING LOW PRESSURE TRACKS FROM NEAR DETROIT TO
SOUTHERN QUEBEC TONIGHT. A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS
THE UPPER MIDWEST AND INTO THE WESTERN GREAT LAKES REGION LATE
TONIGHT...ALLOWING WINDS TO SUBSIDE...BUT WAVES SHOULD REMAIN HIGH
OVER THE SOUTHERN PORTIONS OF THE LAKE INTO WEDNESDAY BEFORE
SETTLING DOWN BELOW SMALL CRAFT ADVISORY LEVELS. HOWEVER...THE
PERIOD OF TIME WITHOUT A MARINE HAZARD HEADLINE WILL BE BRIEF AS
ANOTHER DEEPENING LOW PRESSURE SYSTEM DROPS OUT OF THE NORTHERN
ROCKIES AND MOVES INTO THE WESTERN GREAT LAKES WEDNESDAY NIGHT.
INCREASING SOUTHERLY WINDS ARE EXPECTED AHEAD OF THIS LOW...AND
SINCE THE HIGH WILL BE SLOW TO MOVE OFF TO THE EAST...THE RESULTANT
STRONG PRESSURE GRADIENT MAY LEAD TO MORE GALES OVER THE LAKE. THE
LOW WILL DRAG A COLD FRONT ACROSS THE LAKE LATE WEDNESDAY NIGHT OR
EARLY THURSDAY MORNING...AND THE PUSH OF COLD AIR BEHIND THE FRONT
WILL LIKELY KEEP GALES GOING INTO THURSDAY AFTERNOON. A SLOWER
MOVING HIGH PRESSURE SYSTEM SHOULD THEN BUILD ACROSS THE UPPER
MISSISSIPPI VALLEY INTO THE OHIO VALLEY LATE THIS WEEK AND INTO THE
WEEKEND.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
TUESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
212 PM CST TUE JAN 17 2012
.DISCUSSION...
1243 PM CST
NO MAJOR CHANGES TO GOING FORECAST BUT HAVE PLAYED DOWN SNOW AMOUNTS
THROUGH THIS EVENING ACROSS NORTHERN ILLINOIS. PRIMARY AREA OF FGEN
FORCING IS NOW MOVING AWAY FROM THE FORECAST AREA WITH RADAR
INDICATING WEAKENING RETURNS. SECONDARY AREA OF SNOWFALL ASSOCIATED
WITH H5 VORT MOVING EAST ACROSS THE RIVER ALSO SHOWING WEAKENING
RETURNS...WITH WFO DAVENPORT REPORTING ONLY A COUPLE TENTHS OVER
LAST 6 HOURS...AND OBSERVER NEAR DBQ COMING IN AT 1.6 INCHES FOR SAME
PERIOD. HAVE HAD SEVERAL REPORTS FROM EARLIER THIS MORNING
SUGGESTING SNOWFALL ALREADY AROUND 3 INCHES ACROSS FAR NORTHWEST
PORTION OF CWA...BUT ONLY EXPECT ADDITIONAL SNOW OF AROUND AN INCH
OVER THESE AREAS...WITH...ON THE HIGH SIDE...PERHAPS LOCALIZED
AMOUNTS AROUND 2 INCHES. MORE REALISTICALLY THOUGH...NEW
ACCUMULATION THROUGH THE REMAINDER OF AFTERNOON WILL LIKELY BE UP
TO AN INCH ACROSS THE NORTH...WITH PERHAPS A DUSTING SOUTH OF THE
I-88 CORRIDOR...AND NO ACCUMULATION SOUTH OF THE I-80 CORRIDOR.
AREAS THAT SEE LIGHT ACCUMULATIONS WILL ALSO HAVE TO DEAL WITH
BLOWING AND DRIFTING SNOW AS WINDS CONTINUE TO GUST AROUND AND
ABOVE 30 MPH THIS AFTERNOON. BMD
//PREV DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SNOW CONTINUING THROUGH THE AFTERNOON...ADDITIONAL DUSTING
TO PERHAPS A FEW TENTHS ACCUMULATION.
* VARIABLE VISIBILITY POSSIBLY AS LOW AS 2SM FOR SHORT PERIODS BUT
MAINLY IN THE 3-6SM RANGE
* SNOW ENDING TOWARD 00-01Z.
* MVFR CIGS WITH VARIABLE BASE HEIGHTS CONTINUING THEN SCATTERING
EARLY EVENING.
* NORTHWEST WINDS GUSTING TO 25-30 KT THRU AFTERNOON...THEN
DIMINISHING THIS EVENING.NOON.
MDB
//DISCUSSION...UPDATED 20Z...
RADAR HAS BEEN SHOWING A DOWNWARD TREND IN REFLECTIVITY INTENSITY
OVER THE LAST HOUR OR SO AS BETTER AREA OF SNOW MOVES ACROSS THE
TERMINALS. LIGHT SNOW WILL CONTINUE BUT VISIBILITY REDUCTION HAS
NOT BEEN AS SIGNIFICANT. EXPECT GENERALLY MVFR VSBY WITH BRIEF
DROPS TO AROUND 1 SM POSSIBLE UNDER BETTER SHOW SHOWERS. SNOW WILL
END FROM WEST TO EAST INTO EARLY EVENING WITH SKIES THEN CLEARING
INTO MID EVENING.
MDB
FROM 18Z...
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST IN TERMS OF
VSBY/SNOWFALL. OVERALL RFD WILL SEE THE MOST PERSISTENT SNOWFALL
AND LOWEST CONDITIONS. LATEST OBSERVED TRENDS SHOW A BIT OF A LULL
IN SNOW INTENSITY AND SOME IMPROVEMENT TO VSBY OCCURRING FROM ORD
BACK TO VYS. SO CHI AREA TERMINALS AND GYY WILL PROBABLY SEE A
BRIEF PERIOD OF IMPROVEMENT NEXT 1-2 HOURS. THE MAIN UPPER TROUGH
IS MOVING EASTWARD ACROSS CENTRAL/EASTERN IOWA WHICH WILL BRING
STEADIER SNOW BACK TO THE AREA THIS AFTERNOON. GENERALLY EXPECT
VSBY AROUND 2SM IN LIGHT SNOW TO RETURN TO THE CHI TERMINALS AND
GYY AND CONTINUE FOR SEVERAL HOURS BEFORE ENDING. MAY SEE SOME
VSBY DOWN TO ABOUT A MILE AS WELL. WITH TEMPERATURES FALLING
ACCUMULATION WILL BECOME MORE LIKELY BUT THE STRONG NORTHWEST
WINDS GUSTING IN THE 25-30 KT RANGE WILL BLOW THE SNOW AROUND.
CIGS SHOULD STAY MVFR BUT BASE HEIGHT WILL LIKELY VARY.
SNOW WILL EXIT TO THE EAST LATE THIS AFTERNOON/EARLY THIS EVENING
AND THE END TIME IN THE TAF MAY NEED TO BE TWEAKED. CIGS LOOK TO
QUICKLY SCATTER/CLEAR EARLY THIS EVENING LEAVING VFR OVERNIGHT
WITH VERY COLD CONDITIONS. HIGH PRESSURE WILL MOVE ACROSS THE AREA
OVERNIGHT AND WEDNESDAY MORNING ALLOWING WINDS TO DIMINISH THIS
EVENING THEN TURN SOUTHWEST AND BECOME LIGHT OVERNIGHT. SPEEDS
WILL INCREASE FROM THE SOUTH-SOUTHWEST THROUGH THE DAY WITH MID
AND HIGH CLOUDS INCREASING DURING THE AFTERNOON AHEAD OF A CLIPPER
SYSTEM MOVING NORTH OF THE AREA.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN LIGHT SNOW CONTINUING THROUGH AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN STEADIER LIGHT SNOW ARRIVING BY MID
AFTERNOON WITH ACCUMULATION POSSIBLE.
* HIGH CONFIDENCE IN VARIABLE VISIBILITY IN LIGHT SNOW AND THAT
ANY VSBY AROUND 2SM WOULD BE BRIEF.
* MEDIUM CONFIDENCE IN SPECIFIC END TIME OF SNOW.
* HIGH CONFIDENCE IN MVFR CIGS CONTINUING INTO EARLY EVENING THEN
SCATTERING.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF SNOW. GUSTY SOUTHWEST WINDS
SHIFTING WESTERLY BY MORNING.
* THURSDAY...SLIGHT CHANCE OF SNOW EARLY. GUSTY NORTHWEST WINDS.
* FRIDAY...SNOW. IFR CIGS. LIFR VIS.
* SATURDAY...VFR.
* SUNDAY...VFR. SLIGHT CHANCE OF RAIN LATE.
* MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. CMS
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
TUESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1247 PM CST TUE JAN 17 2012
.DISCUSSION...
1243 PM CST
NO MAJOR CHANGES TO GOING FORECAST BUT HAVE PLAYED DOWN SNOW AMOUNTS
THROUGH THIS EVENING ACROSS NORTHERN ILLINOIS. PRIMARY AREA OF FGEN
FORCING IS NOW MOVING AWAY FROM THE FORECAST AREA WITH RADAR
INDICATING WEAKENING RETURNS. SECONDARY AREA OF SNOWFALL ASSOCIATED
WITH H5 VORT MOVING EAST ACROSS THE RIVER ALSO SHOWING WEAKENING
RETURNS...WITH WFO DAVENPORT REPORTING ONLY A COUPLE TENTHS OVER
LAST 6 HOURS...AND OBSERVER NEAR DBQ COMING IN AT 1.6 INCHES FOR SAME
PERIOD. HAVE HAD SEVERAL REPORTS FROM EARLIER THIS MORNING
SUGGESTING SNOWFALL ALREADY AROUND 3 INCHES ACROSS FAR NORTHWEST
PORTION OF CWA...BUT ONLY EXPECT ADDITIONAL SNOW OF AROUND AN INCH
OVER THESE AREAS...WITH...ON THE HIGH SIDE...PERHAPS LOCALIZED
AMOUNTS AROUND 2 INCHES. MORE REALISTICALLY THOUGH...NEW
ACCUMULATION THROUGH THE REMAINDER OF AFTERNOON WILL LIKELY BE UP
TO AN INCH ACROSS THE NORTH...WITH PERHAPS A DUSTING SOUTH OF THE
I-88 CORRIDOR...AND NO ACCUMULATION SOUTH OF THE I-80 CORRIDOR.
AREAS THAT SEE LIGHT ACCUMULATIONS WILL ALSO HAVE TO DEAL WITH
BLOWING AND DRIFTING SNOW AS WINDS CONTINUE TO GUST AROUND AND
ABOVE 30 MPH THIS AFTERNOON. BMD
&&
.PREV DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT SNOW CONTINUING THROUGH THE AFTERNOON.
* PERIOD OF MORE INTENSE ACCUMULATING SNOW POSSIBLE MID
AFTERNOON.
* SHORT PERIOD OF BETTER VISIBILITY NOW WITH DECREASE BACK TO
AROUND 2SM TOWARD 19-20Z...POSSIBLY AS LOW AS 1SM AT TIMES.
* SNOW WINDS DOWN TOWARD 00-01Z.
* MVFR CIGS WITH VARIABLE BASE HEIGHTS CONTINUING THEN SCATTERING
EARLY EVENING.
* NORTHWEST WINDS GUSTING TO 25-30 KT THRU AFTERNOON...THEN
DIMINISHING THIS EVENING.
* BLOWING SNOW WITH ANY ACCUMULATION THIS AFTERNOON.
MDB
//DISCUSSION...UPDATED 18Z...
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST IN TERMS OF
VSBY/SNOWFALL. OVERALL RFD WILL SEE THE MOST PERSISTENT SNOWFALL
AND LOWEST CONDITIONS. LATEST OBSERVED TRENDS SHOW A BIT OF A LULL
IN SNOW INTENSITY AND SOME IMPROVEMENT TO VSBY OCCURRING FROM ORD
BACK TO VYS. SO CHI AREA TERMINALS AND GYY WILL PROBABLY SEE A
BRIEF PERIOD OF IMPROVEMENT NEXT 1-2 HOURS. THE MAIN UPPER TROUGH
IS MOVING EASTWARD ACROSS CENTRAL/EASTERN IOWA WHICH WILL BRING
STEADIER SNOW BACK TO THE AREA THIS AFTERNOON. GENERALLY EXPECT
VSBY AROUND 2SM IN LIGHT SNOW TO RETURN TO THE CHI TERMINALS AND
GYY AND CONTINUE FOR SEVERAL HOURS BEFORE ENDING. MAY SEE SOME
VSBY DOWN TO ABOUT A MILE AS WELL. WITH TEMPERATURES FALLING
ACCUMULATION WILL BECOME MORE LIKELY BUT THE STRONG NORTHWEST
WINDS GUSTING IN THE 25-30 KT RANGE WILL BLOW THE SNOW AROUND.
CIGS SHOULD STAY MVFR BUT BASE HEIGHT WILL LIKELY VARY.
SNOW WILL EXIT TO THE EAST LATE THIS AFTERNOON/EARLY THIS EVENING
AND THE END TIME IN THE TAF MAY NEED TO BE TWEAKED. CIGS LOOK TO
QUICKLY SCATTER/CLEAR EARLY THIS EVENING LEAVING VFR OVERNIGHT
WITH VERY COLD CONDITIONS. HIGH PRESSURE WILL MOVE ACROSS THE AREA
OVERNIGHT AND WEDNESDAY MORNING ALLOWING WINDS TO DIMINISH THIS
EVENING THEN TURN SOUTHWEST AND BECOME LIGHT OVERNIGHT. SPEEDS
WILL INCREASE FROM THE SOUTH-SOUTHWEST THROUGH THE DAY WITH MID
AND HIGH CLOUDS INCREASING DURING THE AFTERNOON AHEAD OF A CLIPPER
SYSTEM MOVING NORTH OF THE AREA.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN LIGHT SNOW CONTINUING THROUGH AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN STEADIER LIGHT SNOW ARRIVING BY MID
AFTERNOON WITH ACCUMULATION POSSIBLE.
* HIGH CONFIDENCE IN BETTER VISIBILITY NEXT HOUR OR 2 WITH MEDIUM-
HIGH CONFIDENCE IN VSBY FALLING TOWARD 19-20 AS SNOW INCREASES
...LOW-MEDIUM CONFIDENCE IN SPECIFIC VSBY VALUES MID AFTERNOON IN
BETTER SNOW.
* MEDIUM CONFIDENCE IN END TIME OF SNOW.
* HIGH CONFIDENCE IN MVFR CIGS CONTINUING INTO EARLY EVENING THEN
SCATTERING.
* HIGH CONFIDENCE THAT AT LEAST SOME BLOWING SNOW WILL OCCUR WITH
ANY ACCUMULATING SNOW.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF SNOW. GUSTY SOUTHWEST WINDS
SHIFTING WESTERLY BY MORNING.
* THURSDAY...SLIGHT CHANCE OF SNOW EARLY. GUSTY NORTHWEST WINDS.
* FRIDAY...SNOW. IFR CIGS. LIFR VIS.
* SATURDAY...VFR.
* SUNDAY...VFR. SLIGHT CHANCE OF RAIN LATE.
* MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. CMS
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
TUESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1207 PM CST TUE JAN 17 2012
.DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT SNOW CONTINUING THROUGH THE AFTERNOON.
* PERIOD OF MORE INTENSE ACCUMULATING SNOW POSSIBLE MID
AFTERNOON.
* SHORT PERIOD OF BETTER VISIBILITY NOW WITH DECREASE BACK TO
AROUND 2SM TOWARD 19-20Z...POSSIBLY AS LOW AS 1SM AT TIMES.
* SNOW WINDS DOWN TOWARD 00-01Z.
* MVFR CIGS WITH VARIABLE BASE HEIGHTS CONTINUING THEN SCATTERING
EARLY EVENING.
* NORTHWEST WINDS GUSTING TO 25-30 KT THRU AFTERNOON...THEN
DIMINISHING THIS EVENING.
* BLOWING SNOW WITH ANY ACCUMULATION THIS AFTERNOON.
MDB
//DISCUSSION...UPDATED 18Z...
HAVE MADE SOME ADJUSTMENTS TO THE FORECAST IN TERMS OF
VSBY/SNOWFALL. OVERALL RFD WILL SEE THE MOST PERSISTENT SNOWFALL
AND LOWEST CONDITIONS. LATEST OBSERVED TRENDS SHOW A BIT OF A LULL
IN SNOW INTENSITY AND SOME IMPROVEMENT TO VSBY OCCURRING FROM ORD
BACK TO VYS. SO CHI AREA TERMINALS AND GYY WILL PROBABLY SEE A
BRIEF PERIOD OF IMPROVEMENT NEXT 1-2 HOURS. THE MAIN UPPER TROUGH
IS MOVING EASTWARD ACROSS CENTRAL/EASTERN IOWA WHICH WILL BRING
STEADIER SNOW BACK TO THE AREA THIS AFTERNOON. GENERALLY EXPECT
VSBY AROUND 2SM IN LIGHT SNOW TO RETURN TO THE CHI TERMINALS AND
GYY AND CONTINUE FOR SEVERAL HOURS BEFORE ENDING. MAY SEE SOME
VSBY DOWN TO ABOUT A MILE AS WELL. WITH TEMPERATURES FALLING
ACCUMULATION WILL BECOME MORE LIKELY BUT THE STRONG NORTHWEST
WINDS GUSTING IN THE 25-30 KT RANGE WILL BLOW THE SNOW AROUND.
CIGS SHOULD STAY MVFR BUT BASE HEIGHT WILL LIKELY VARY.
SNOW WILL EXIT TO THE EAST LATE THIS AFTERNOON/EARLY THIS EVENING
AND THE END TIME IN THE TAF MAY NEED TO BE TWEAKED. CIGS LOOK TO
QUICKLY SCATTER/CLEAR EARLY THIS EVENING LEAVING VFR OVERNIGHT
WITH VERY COLD CONDITIONS. HIGH PRESSURE WILL MOVE ACROSS THE AREA
OVERNIGHT AND WEDNESDAY MORNING ALLOWING WINDS TO DIMINISH THIS
EVENING THEN TURN SOUTHWEST AND BECOME LIGHT OVERNIGHT. SPEEDS
WILL INCREASE FROM THE SOUTH-SOUTHWEST THROUGH THE DAY WITH MID
AND HIGH CLOUDS INCREASING DURING THE AFTERNOON AHEAD OF A CLIPPER
SYSTEM MOVING NORTH OF THE AREA.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN LIGHT SNOW CONTINUING THROUGH AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN STEADIER LIGHT SNOW ARRIVING BY MID
AFTERNOON WITH ACCUMULATION POSSIBLE.
* HIGH CONFIDENCE IN BETTER VISIBILITY NEXT HOUR OR 2 WITH MEDIUM-
HIGH CONFIDENCE IN VSBY FALLING TOWARD 19-20 AS SNOW INCREASES
...LOW-MEDIUM CONFIDENCE IN SPECIFIC VSBY VALUES MID AFTERNOON IN
BETTER SNOW.
* MEDIUM CONFIDENCE IN END TIME OF SNOW.
* HIGH CONFIDENCE IN MVFR CIGS CONTINUING INTO EARLY EVENING THEN
SCATTERING.
* HIGH CONFIDENCE THAT AT LEAST SOME BLOWING SNOW WILL OCCUR WITH
ANY ACCUMULATING SNOW.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF SNOW. GUSTY SOUTHWEST WINDS
SHIFTING WESTERLY BY MORNING.
* THURSDAY...SLIGHT CHANCE OF SNOW EARLY. GUSTY NORTHWEST WINDS.
* FRIDAY...SNOW. IFR CIGS. LIFR VIS.
* SATURDAY...VFR.
* SUNDAY...VFR. SLIGHT CHANCE OF RAIN LATE.
* MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. CMS
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
TUESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1040 AM CST TUE JAN 17 2012
.DISCUSSION...
354 AM CST
MAIN CONCERNS REVOLVE AROUND VARYING PRECIP TYPE EARLY THIS
MORNING WITH RAIN/THUNDERSTORMS CURRENTLY ONGOING ACROSS THE
SOUTHERN HALF OF THE CWA AND RAIN FOR THE MIDDLE HALF...BUT WITH A
TRANSITION OVER TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THIS
MORNING. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE TOP TIER OF
COUNTIES IN ILLINOIS WITH SNOWFALL TOTALS IN NORTHERN ILLINOIS
PUSHING 3-4 INCHES...AND ISSUES WITH REDUCED VISIBILITY DUE TO
BLOWING SNOW.
VERY COMPLEX SITUATION ONGOING ACROSS THE CWA THIS MORNING AS A
WIDE RANGE OF FORECAST CONCERNS REMAIN...WITH CURRENTLY KEEPING AN
EYE ON THUNDERSTORM POTENTIAL FOR THE FAR SOUTHERN AREA OF THE
CWA. LATEST RADAR IMAGERY IS SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY MOVING EAST/NORTHEAST FROM CENTRAL
ILLINOIS NORTHEAST TO NORTHERN INDIANA. THESE THUNDERSTORMS ARE
DEVELOPING IN THE WARM SECTOR OF CURRENT SURFACE LOW SITUATED OVER
EAST CENTRAL ILLINOIS. IN THIS WARM SECTOR...TEMPERATURES HAVE
RISEN TO THE LOW TO MID 50S WITH SURFACE DEWPOINTS ALSO RISING TO
THE LOWER 50S. THIS IS PROVIDING FOR A FAIRLY UNSTABLE ENVIRONMENT
FOR THIS TIME OF THE YEAR WITH MID LEVEL LAPSE RATES ON THE
INCREASE AS WELL AS LATEST RUC ANALYSIS INDICATING THAT AN
INSTABILITY AXIS WITH AROUND 500J/KG OF MUCAPE IS SITUATED FROM
SOUTHERN ILLINOIS TO NORTHERN INDIANA. ALL OF THESE ELEMENTS
COINCIDING WITH STRONG LOW AND MID LEVEL CONVERGENCE...A 50KT
LLJ...AND LARGE SCALE FORCING FOR ASCENT OWING TO SEVERAL MID
LEVEL FEATURES PROPAGATING TO THE NORTHEAST OUT AHEAD OF A
LONGWAVE TROUGH TO THE WEST...IS PROVIDING A DECENT SETUP FOR
THUNDERSTORM DEVELOPMENT ACROSS PART OF THE AREA. STRONG MID LEVEL
FLOW IS AIDING IN DECENT BULK SHEAR VALUES RIGHT ACROSS THE
SOUTHERN CWA THIS MORNING. A FEW STORMS HAVE BEEN ABLE TO REALIZE
ALL OF THIS WITH SOME MORE ORGANIZED STORMS RIDING ALONG JUST TO
THE SOUTH OF THE CWA. ALTHOUGH LATEST TRENDS AND SURFACE
OBSERVATIONS LEAD ME TO BELIEVE THAT OUR CWA HAS SEEN THE WINDOW
OF OPPORTUNITY FOR GOOD THUNDERSTORM DEVELOPMENT...WITH BETTER
CHANCES FOR MORE ORGANIZED CONVECTION TO REMAIN JUST TO THE
SOUTH/SOUTHEAST OF THE CWA.
WILL THEN SHIFT GEARS BACK TOWARDS MORE WINTER TIME PRECIP
EXPECTED OVER THIS MORNING. AS MID/UPPER LEVEL TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND CURRENT SURFACE LOW SHIFTS
EAST...LATEST RADAR IMAGERY IS SHOWING AN AREA OF SNOWFALL
CONTINUING TO DEVELOP AND SHIFT EAST ACROSS CENTRAL IOWA EARLY
THIS MORNING. EXPECT THIS PRECIP TO SHIFT EAST ACROSS THE NORTHERN
HALF OF THE CWA THIS MORNING WITH AREAS ACROSS NORTHWEST/NORTHERN
ILLINOIS OBSERVING SNOW...AND AREAS FROM LA SALLE NORTHEAST TO
CHICAGO INITIALLY OBSERVING RAIN AND THEN A RAIN/SNOW MIX THROUGH
MID MORNING. HAVE REMOVED ANY MENTION OF FREEZING RAIN FOR THIS
MORNING...NOT EXPECTING THIS TO BE A THREAT ANYMORE ANYWHERE
ACROSS THE CWA AS SURFACE TEMPERATURES REMAIN WELL ABOVE FREEZING.
WITH COLDER AIR AND DEEPER MOISTURE QUICKLY SHIFTING EAST THIS
MORNING...A MORE LIKELY SCENARIO WILL BE A QUICK TRANSITION OVER
TO SNOW THROUGH MID MORNING AS LARGE SCALE FORCING/MID LEVEL
TROUGH SHIFT EAST WITH THIS DEFORMATION ZONE ALSO MOVING INTO THE
CWA. MODEL GUIDANCE IN FAIR AGREEMENT WITH LATEST TRENDS TODAY
WITH BEST FORCING ARRIVING LATE THIS MORNING INTO THE NOON TIME
FRAME AS LOW AND MID LEVEL FRONTOGENESIS HELPS TO MAXIMIZE LIFT.
THIS ENHANCED LIFT WILL ALSO COINCIDE WITH STEEPENING MID LEVEL
LAPSE RATES THROUGH THIS TIME...WITH LIGHT TO MODERATE SNOW
FALLING AT TIMES. CURRENT TRENDS AND GUIDANCE WOULD SUGGEST THAT
BEST FORCING AND HIGHER SNOWFALL AMOUNTS WILL OCCUR MORE TOWARDS
THE NORTHERN PORTIONS OF THE CWA WHERE AROUND 3 INCHES OF SNOW IS
CURRENTLY FORECAST...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IF
BANDED SNOWFALL COULD GET GOING. THIS SNOW WILL INITIALLY BE A WET
SNOW ACROSS THE CWA...BUT WITH COLDER AIR QUICKLY SWEEPING
THROUGH...EXPECT SNOW TO BECOME DRIER INTO THE EARLY AFTERNOON.
THIS DRIER SNOW WILL BECOME PROBLEMATIC AS LOW LEVEL MIXING WILL
HELP WIND GUSTS OF 30-40MPH TO DEVELOP...AND BLOWING SNOW BECOMING
AN ISSUE ACROSS MUCH OF NORTHERN ILLINOIS.
AREAS FROM LA SALLE TO CHICAGO CAN EXPECT SNOW TO BECOME MORE
PREVAILING BY THE MID MORNING TIME FRAME...WITH 1 TO 3 INCHES
EXPECTED IN THIS GENERAL AREA TODAY. AREAS IN THE SOUTHERN HALF OF
THE CWA CAN EXPECT A CHANGE OVER TO ALL SNOW BY MID DAY WHERE 1 TO
2 INCHES WILL BE POSSIBLE. EXPECT SNOW TO CONTINUE INTO THE
AFTERNOON...BUT WITH GUIDANCE INDICATING THAT MUCH DRIER AIR WILL
BEGIN TO FILTER IN FROM THE SOUTHWEST. THIS COULD POSSIBLY BRING A
PERIOD OF DRIER CONDITIONS FOR THE FAR SOUTHERN TIER OF COUNTIES
IN THE CWA INTO THE AFTERNOON BEFORE WRAP MOISTURE SHIFTS EAST. IN
ALL...SNOW WILL BE DIMINISHING LATE THIS AFTERNOON INTO THE EARLY
EVENING. HIGH PRESSURE WILL THEN SHIFT OVER THE REGION TONIGHT
WITH SKIES CLEARING AND TEMPERATURES FALLING...AS MUCH COLDER
CONDITIONS EXPECTED TONIGHT WITH FORECAST LOWS IN THE SINGLE
DIGITS POSSIBLE.
RODRIGUEZ
EXTENDED...FRIDAY THROUGH MONDAY...
218 AM CST...
THE MAIN CONCERNS DURING THE EXTENDED PERIOD WILL INITIALLY BE WITH
SNOWFALL CHANCES ON FRIDAY...AND THEN THE POTENTIAL FOR A
SIGNIFICANT WARM UP BY EARLY NEXT WEEK.
MID AND UPPER LEVEL ENERGY IS EXPECTED TO UNDERCUT THE BLOCKING
RIDGE OF HIGH PRESSURE ACROSS THE BERING SEA DURING THE SHORT TERM
PERIOD. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE TO DIG EAST
SOUTHEASTWARD THROUGH THE FAST WEST NORTHWEST FLOW ACROSS THE CONUS
LATER THIS WEEK. THERE ARE SOME SLIGHT TIMING DIFFERENCES AMONGST
THE VARIOUS MODEL GUIDANCE. HOWEVER...THE OVERALL CONSENSUS IS TO
BRING THE PRECIPITATION ACROSS NORTHERN ILLINOIS AND NORTHWESTERN
INDIANA ON FRIDAY AND FRIDAY EVENING.
IT APPEARS THAT ALTHOUGH THIS WILL BE A RATHER FAST MOVING
SYSTEM...THERE WILL BE A SHOT OF GETTING A FAIR AMOUNT OF SNOW
ACROSS A PORTION OF THE GREAT LAKES REGION. THERE WILL LIKELY BE A
STRONG BAROCLINIC ZONE ACROSS THE AREA...SETTING THE STAGE FOR A
POSSIBLE STRONGLY FORCED FRONTOGENETIC BAND OF SNOW. SNOW RATIOS WOULD
ALSO LIKELY BE FAIRLY HIGH...AROUND 20 TO 1 OR POSSIBLY HIGHER IN
SOME AREAS AS TEMPERATURES THROUGH THE COLUMN LOOK COLD. BUFFER
SOUNDINGS FROM THE GFS SUGGEST AN INCREDIBLY DEEP SATURATED DENDRITIC
GROWTH LAYER...FROM NEAR THE SURFACE UP TO AROUND 550MB. THIS COULD
SET UP EFFICIENT SNOWFALL PRODUCTION.
DEPENDING ON IF AND HOW MUCH SNOW OCCURS ON FRIDAY WILL DEPEND HOW
QUICKLY THINGS WARM UP OVER THE WEEKEND. HOWEVER...IT DOES APPEAR
THAT A SIGNIFICANT WARM UP WILL TAKE PLACE BY LATE WEEKEND INTO
EARLY NEXT WEEK. THIS WILL OCCUR AS THE LARGE SCALE PATTERN ACROSS
NORTHERN AMERICA SHIFTS. A SIGNIFICANT CHUNK OF THE POLAR VORTEX
ACROSS NORTHERN CANADA WILL BE FORCED SOUTHWESTWARD ACROSS ALASKA
AND THE NORTHEAST PACIFIC. THE RESULT OF THIS WILL BE RISING HEIGHTS
ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THIS WILL LIKELY
RESULT IN A RETURN TO SOME UNSEASONABLE MILD WEATHER ACROSS THE
REGION INTO NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TRANSITION FROM RAIN/DRIZZLE TO SNOW OCCURRING AT MDW THIS
HOUR...ALREADY SNOW AT ORD.
* PERIODS OF LIGHT SNOW CONTINUING THROUGH MID AFTERNOON.
* PERIOD OF POTENTIAL ACCUMULATION AND LOWEST VSBY REDUCTION MAY
BE DELAYED UNTIL EARLY AFTERNOON...TAF ADJUSTMENTS POSSIBLE.
* PRIMARILY MVFR CIGS THROUGH AFTERNOON THOUGH SPOTTY IFR MAY
OCCUR YET THIS MORNING AT ORD...IFR TO BECOME MVFR AT MDW SOON
* NORTHWEST WINDS GUSTING TO AROUND 30 KT THROUGH MID AFTERNOON
THEN SLOWLY DIMINISHING.
* POTENTIAL FOR BLOWING SNOW AND SOME VSBY REDUCTION DUE TO IT
ASSUMING SNOW CAN ACCUMULATE.
MDB
//DISCUSSION...UPDATED 16Z...
DETAILS HAVE BECOME MORE CHALLENGING IN TERMS OF VSBY AND SNOW
DETAILS. BANDS OF SNOW CONTINUE TO GENERATE ACROSS EASTERN IOWA
AND MOVE EAST-NORTHEAST. HOWEVER...MUCH OF THE SOUTHERN FLANK OF
THIS DIMINISHES AS IT MOVES CLOSER TO THE AREA. LIGHT SNOW WILL
CONTINUE BUT AM CONCERNED THAT THE POTENTIAL FOR ACCUMULATING SNOW
AND LOWER VSBY IN SNOW/BLSN WILL BE SHIFTED INTO EARLY AFTERNOON
BASED ON LATEST TRENDS. MAY NEED TO MAKE TAF ADJUSTMENTS. CIGS
CONTINUE TO IMPROVE WITH IFR CHANGING TO MVFR AND THEN REMAINING
MVFR THROUGH THE AFTERNOON. NORTHWEST WINDS HAVE COME UP WITH GUSTS
TO AROUND 30 KT. THIS WILL LEAD TO BLOWING SNOW WHERE SNOW
ACCUMULATES AND MAGNITUDE OF ACCUMULATION HAS BECOME LESS CERTAIN
ACROSS THE CHI METRO AIRPORTS...ESPECIALLY MDW/GYY. WILL CONTINUE
TO MONITOR VSBY AND SNOW INTENSITY TRENDS FOR POTENTIAL
ADJUSTMENTS.
MDB
FROM 12Z...
LOW PRESSURE CURRENTLY CENTERED OVER NORTHEAST INDIANA WILL
CONTINUE TO NEAR TORONTO BY THIS EVENING. COLDER AIR WILL SLOWLY
SPREAD ACROSS THE AREA THIS MORNING AS NORTHERLY WINDS ALSO
STEADILY INCREASE AND BECOME QUITE STRONG BY MID/LATE MORNING.
BULK OF THE RAIN HAS SHIFTED EAST OF THE TERMINALS. STILL A FEW
SHOWERS AND DRIZZLE BUT AS THE COLDER AIR SPREADS ACROSS NORTHWEST
IL...PRECIP WILL BEGIN TO TRANSITION TO SNOW. CHANGEOVER SHOULD
OCCUR RATHER QUICKLY WITH SNOW INTO THE CHICAGO AREA TERMINALS BY
15Z OR SO. COULD BE A BRIEF PERIOD OF SLEET OR FREEZING RAIN...
BUT NOT EXPECTING THIS TO BECOMING PREVAILING. THE HEAVIEST OF THE
SNOW IS EXPECTED TO FALL ACROSS FAR NORTHERN IL INTO SOUTHERN
WI...SO THERE REMAINS SOME UNCERTAINTY AS TO JUST HOW LOW CIGS/VIS
WILL DROP AND HOW MUCH SNOW MAY FALL. IN ADDITION...THE SNOW WILL
LIKELY START SOMEWHAT WET AND STEADILY BECOME DRIER OR FLUFFY AS
SNOW/WATER RATIOS INCREASE. WITH THE GRADIENT TIGHTENING ON THE
BACK SIDE OF THE DEPARTING LOW...WINDS GUSTING 25-30 KTS WILL
LIKELY CAUSE BLOWING AND DRIFTING OF THIS DRIER SNOW...WHEREVER IT
FALLS. THE PERIOD OF TIME OF THE HEAVIEST SNOW WILL LIKELY BE
CENTERED AROUND 18Z WITH SNOW ENDING FROM WEST TO EAST DURING THE
EARLY/MID AFTERNOON HRS. GIVEN THE UNCERTAINTY REGARDING
CIGS/VIS...REFINEMENTS...PERHAPS SIGNIFICANT...WITH LATER UPDATES
SHOULD BE EXPECTED.
MVFR CIGS SHOULD LIFT TO VFR BY EARLY EVENING...AND SCATTER OUT BY
EARLY MORNING. NORTHWEST WINDS WILL REMAIN GUSTY DURING THE
EVENING BUT WILL STEADILY DIMINISH LATE IN THE EVENING INTO THE
OVERNIGHT HOURS AS A RIDGE OF HIGH PRESSURE MOVES ACROSS THE AREA
WEDNESDAY MORNING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN TRANSITION FROM RAIN TO SNOW AT MDW.
* HIGH CONFIDENCE IN LIGHT SNOW CONTINUING THROUGH MID
AFTERNOON...THOUGH LOW-MEDIUM CONFIDENCE ON ENDING TIME.
* LOW CONFIDENCE IN PERIOD FOR BEST ACCUMULATION POTENTIAL AND
LOWEST VSBY DUE TO SNOW...MAY BE MORE TOWARDS EARLY AFTERNOON.
* HIGH CONFIDENCE IN CEILING TRENDS.
* HIGH CONFIDENCE IN WINDS.
* HIGH CONFIDENCE IN BLOWING SNOW OCCURRING IF ACCUMULATION OCCURS
BUT REDUCED CONFIDENCE IN ACCUMULATION AMOUNTS.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF SNOW. GUSTY SOUTHWEST WINDS
SHIFTING WESTERLY BY MORNING.
* THURSDAY...SLIGHT CHANCE OF SNOW EARLY. GUSTY NORTHWEST WINDS.
* FRIDAY...SNOW. IFR CIGS. LIFR VIS.
* SATURDAY...VFR.
* SUNDAY...VFR. SLIGHT CHANCE OF RAIN LATE.
* MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. CMS
&&
.MARINE...
254 AM CST
LOW PRESSURE CONTINUES TO LIFT NORTHEAST ACROSS CENTRAL
QUEBEC...WITH A TRAILING AND NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING SOUTHWEST THROUGH NORTHWEST IN/CENTRAL IL. A SERIES OF
WEAK LOW PRESSURE HAVE MOVED ALONG THIS BOUNDARY...HOWEVER GUIDANCE
IS INDICATING THAT TODAY THE BOUNDARY WILL BEGIN TO ADVANCE
EAST/SOUTHEAST AS A PUSH OF MUCH COLDER AIR ARRIVES. EARLY THIS
MORNING OBSERVATIONS HAVE INDICATED WIND GUSTS BETWEEN 10 TO 20 KT
GENERALLY FROM THE NORTH. WITH THE LACK OF A SIGNIFICANT PRESSURE
GRADIENT EARLY THIS MORNING WINDS SHOULD REMAIN LIGHT FOR A BRIEF
PERIOD OF TIME...BEFORE STEADILY RAMPING UP TOWARDS GALES FOR THE
OPEN WATERS AND SOLID SMALL CRAFT CONDITIONS FOR THE NEARSHORE
WATERS.
GUIDANCE HAS CONTINUED TO FOCUS ON A 15-18Z WINDOW FOR WINDS PUSHING
TO 35-40KT ACROSS THE OPEN WATERS OF LAKE MICHIGAN. SREF NEAR SFC
WIND PLUMES HAVE SUGGESTED WINDS AT 18Z WILL BE SUSTAINED ARND 20KT.
THIS COUPLED WITH A HIGH CONFIDENCE OF THE MIXED LAYER BRINGING TO
THE SFC WINDS ARND 850MB OF 40-45KT...SUGGEST HEAVILY THAT GALES
CONFIDENCE IS NEAR 100 PERCENT. THEN BASED ON OPERATIONAL MODELS AND
ENSEMBLES WINDS RAPIDLY DECLINE BY 06Z WED TO ARND 10-20KT
SUSTAINED...AND GUSTS TO 30KT. THIS SHOULD BRING AN END TO THE
GALES...HOWEVER INFREQUENT GALES TO 35KT MAY OCCUR FOR A FEW HOURS
AFT 06Z WED. SMALL CRAFT CONDITIONS WILL PERSIST FOR THE NORTHWEST
INDIANA WATERS THROUGH WED MORNING UNDER A NW FLOW AND ELEVATED
WAVES.
HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST/SOUTHWEST...AND SHOULD
RELAX WINDS FOR THE REMAINDER OF THE NIGHT INTO EARLY WED. THEN YET
ANOTHER SYSTEM IS PROGGED TO DEVELOP WED NGT AS THE HIGH PRESSURE
DRIFTS EAST. THIS WILL ALLOW A TIGHTENING PRESSURE GRADIENT LATE WED
AS WINDS BACK TO THE SOUTHWEST. CURRENT INDICATIONS ARE THAT LOW END
GALES ARE POSSIBLE EARLY THUR MORNING. THEN A BROAD HIGH PRESSURE
AREA BUILDS IN FROM THE NW AND SHUD PROVIDE A PERIOD OF LIGHTER
WINDS FOR FRI. THEN WINDS SHUD QUIET DOWN FOR A FEW PERIODS. THEN
FOR THE SECOND HALF OF THE UPCOMING WEEKEND...MUCH WARMER AIR MAY
SLIDE OVER LAKE MICHIGAN SUN. THIS HAS THE POTENTIAL OF CREATING A
RARE LATE JANUARY STABLE MARINE ENVIRONMENT SUN. CONFIDENCE AT THIS
JUNCTURE IS VERY LOW...HOWEVER SOME CONSISTENCY HAS BEEN NOTED
AMONGST FORECAST SOLUTIONS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
TUESDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 10 PM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
536 PM EST TUE JAN 17 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST ACROSS THE EASTERN GREAT LAKES
THIS EVENING...WITH THE ASSOCIATED COLD FRONT PUSHING THROUGH THE
MID ATLANTIC LATE TONIGHT INTO WEDNESDAY MORNING. HIGH PRESSURE
BUILDS INTO...AND THEN OVER THE REGION WEDNESDAY NIGHT THROUGH
THURSDAY. A WEAK TROUGH PASSES ACROSS THE REGION THURSDAY NIGHT
FOLLOWED BY A RETURN OF HIGH PRESSURE FRIDAY.
&&
.NEAR TERM /TONIGHT/...
QUICK UPDATE TO ACCOUNT FOR LATEST RADAR TRENDS THIS EVENING.
INCREASED POPS ACROSS WESTERN COUNTYS NEXT FEW HOURS IN RESPONSE
TO THE BAND OF SHOWERS QUICKLY APPROACHING THE AREA OUT AHEAD OF
THE COLD FRONT. LATEST RUC SEEMS TO HAVE THE BEST HANDLE WITH THESE
SHOWERS WITH THE HIGHEST POPS ACROSS WESTERN PIEDMONT COUNTYS THIS
EVENING. ALSO UPDATED HWO TO ACCOUNT FOR POTENTIAL WIND GUSTS TO
AROUND 40 MPH LATER TONIGHT WITH THE ACTUAL FROPA.
PREVIOUS DSCN:
THE LATEST WX ANALYSIS SHOWS A ~995 MB SURFACE LOW OVER SOUTHERN
ONTARIO WITH A COLD FRONT EXTENDING TO THE SW INTO THE MID-SOUTH
THIS AFTN. VIS/IR SATELLITE IMAGERY AND LIGHTING DATA REVEALS
CONVECTION NEAR THE LOW CENTER AND ALONG THE SURGING BOUNDARY OVER
EASTERN SECTIONS OF OH/KY. TO THE SOUTHEAST...LATEST REGIONAL
RADAR MOSAIC CONTINUES TO SHOW LIGHT WAA RAIN PULLING OFFSHORE
ATTM...WITH A BRIEF LULL IN POPS EXPECTED THROUGH THE EARLY
EVENING HOURS.
OTHER ISSUE OF NOTE TODAY IS THE GUSTY WINDS. AKQ VWP CONTINUES TO
INDICATE A 40-50 KT LOW LEVEL JET BETWEEN 2-3KFT AGL AT 20Z.
DESPITE DIURNAL LIFTING OF THE LLJ...GUSTY SW WINDS WILL CONTINUE
INTO THE EARLY EVENING HOURS. SUSTAINED WIND SPEEDS IN THE 20-25
MPH RANGE WL CONTINUE...W/FREQUENT GUSTS TO 30-35 MPH EXPECTED
THROUGH LATE AFTERNOON.
THE AFOREMENTIONED TROUGH RACES NORTHEAST INTO NORTHERN NEW
ENGLAND/SOUTHERN QUEBEC BY LATE TONIGHT, DRAGGING A STRONG COLD
FRONT THROUGH THE MID ATLANTIC AFTER MIDNIGHT TONIGHT INTO
WEDNESDAY MORNING. ADDITIONAL SHORTWAVE ENERGY, NOTED ON MID-
AFTERNOON SAT IMAGERY OVER THE CENTRAL GULF COAST, WILL TRIGGER A
WAVE ALONG THE FRONT. HIGH FORECAST CONFIDENCE REMAINS THAT THIS
FEATURE WILL ALLOW FOR ANOTHER PERIOD OF LIGHT RAIN ACROSS THE
REGION, WITH LIKELY TO CATEGORICAL POPS REMAINING FOR THE
TIDEWATER AND MOST OF NE NC...BUFFERED BY LOWER SHRA CHCS FARTHER
NORTH INTO RICHMOND METRO. QPF VALUES EXPECTED TO REMAIN QUITE
LIGHT...ON THE ORDER OF A QUARTER INCH OR LESS, WITH HIGHEST
AMOUNTS OVER NE NC. TEMPERATURES REMAIN VERY MILD THIS EVENING
MOST OF THE NIGHT AHEAD OF THE FRONT...BEFORE FALLING LATE. A
BRIEF PERIOD OF STRONGER WIND GUSTS IS POSSIBLE AS THE COLDER AIR
RUSHES IN.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
FRONT SLIDES OFFSHORE BY EARLY WEDNESDAY...WITH RAPID CLEARING
ENSUING THROUGH THE MORNING OVER THE WEST...REACHING THE COAST BY
EARLY TO MID AFTERNOON. HIGH TEMPERATURES WL LKLY BE ACHIEVED
EARLY IN THE DAY AND SHOULD GENERALLY RUN IN THE LOW TO MID 40S N
AND W...AND IN THE LOW 50S SE EARLY BEFORE FALLING INTO THE UPPER
40S LATE.
WED NIGHT-FRIDAY...
QUIET AND SEASONABLE CONDITIONS ARE EXPECTED WEDNESDAY NIGHT INTO
THURSDAY. A PERIOD OF PARTLY CLOUDY CONDITIONS WILL BE POSSIBLE
MAINLY ACROSS COASTAL SITES, AS A MOISTURE STARVED MID-LEVEL
TROUGH PASSES ACROSS THE REGION FOLLOWED BY A PERIOD OF CLEARING
THURSDAY MORNING AS HIGH PRESSURE MOVES OVERHEAD...SLIDING
OFFSHORE BY THURSDAY AFTERNOON. RESULTANT WAA THU AFTN/ EVENING WL
TRANSLATE TO INCREASING AFTN CLOUDINESS AHEAD OF NEXT SYSTEM AND
COLD FRONT APPROACH FROM THE WEST.
WEAK COLD FRONT LOOKS TO CROSS INTO THE AREA AS IT WEAKENS/WASHES
OUT FRIDAY MORNING. AS SUCH...EXPECT A CLOUDY NIGHT THU
NIGHT/EARLY FRIDAY AND LTL/NO PCPN WITH ITS PASSAGE. QUICK
CLEARING ONCE AGAIN BEHIND THE FRONT WITH CAA ON FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MAIN FOCUS FOR THE LONG TERM PERIOD IS LO PRES TRAVERSING THE
EASTERN CONUS FRI INTO SAT. WAA PRECIP OUT AHEAD OF THIS SYSTEM WILL
BEGIN SAT MORNING THROUGH MIDDAY. WARMING TRENDS IN LO-LEVEL
THICKNESSES SUGGEST THAT THE PRECIP WILL START MSTLY AS RN...BUT
SOME MIXED PRECIP MAY MIX IN OVER FAR NORTHERN AREA BEFORE QUICKLY
CHANGING TO ALL RN. HAVE BUMPED UP POPS TO 60% ON SAT AS MODELS
HAVE CONTINUED TO SHOW GOOD TIME CONTINUITY W/ THIS SYSTEM. TEMPS ON
SAT MAY HAVE A LARGE NORTH TO SOUTH SPREAD W/ A WARM FRONT IN THE
VICINITY...CURRENT FORECAST CALLS FOR HIGHS THAT RANGE FROM THE
UPR 40S OVER NORTHERN PARTS OF THE FA TO NEAR 60 OVER NE NC.
MID-LEVEL S/W RIDGE DEVELOPS ON SUN ALLOWING TEMPS TO CLIMB INTO THE
THE MID 50S TO LWR 60S IN MOST SPOTS. WARMING TREND CONTINUES INTO
MON AS A S/W TROUGH MISSES TO THE NORTH AND UPPER HEIGHTS RISE. A LO
PRES SYSTEM APPROACHES FROM THE WEST MON NGT INTO TUE...BUT WILL
FORECAST SILENT POPS (20%) FOR NOW THIS FAR OUT IN TIME.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
LOW PRESSURE CENTERED OVER NORTHERN INDIANA EARLY THIS AFTERNOON
WITH A COLD FRONT EXTENDING INTO TX. A WARM FRONT ALSO EXTENDS
ACROSS THE MID ATL REGION WITH STRONG S-SW FLOW OVER THE AREA. WIND
GUSTS TO 20-30 KT EXPECTED THRU THE AFTERNOON AND EARLY EVENING. A
BAND OF LIGHT TO MODERATE SHOWERS WILL PASS THRU THE CWA THIS
AFTERNOON. EXPECT CONDITIONS TO GENERALLY STAY VFR WITH CEILINGS
AVERAGING 4000-7000 FT. RADAR SHOWING LITTLE PRECIP BETWEEN THIS
BAND AND SHOWERS ASSOCIATED WITH THE COLD FRONT.
THE COLD FRONT WILL PUSH INTO THE MID ATL REGION TONIGHT AND PASS
OFFSHORE BEFORE SUNRISE WEDNESDAY. SHOWERS SHOULD ACCOMPANY THE
FRONT AS IT MOVES THRU WITH GUSTY WINDS 20-30 KT AND HIGHER. WINDS
WILL SHIFT TO NW-N BEHIND THE FRONT AND START TO DIMINISH DURING THE
AFTERNOON. HIGH PRESSURE WILL BUILD IN WEDNESDAY AFTERNOON. VFR
CONDITIONS EXPECTED THRU FRIDAY.
&&
.MARINE...
LO PRES OVER THE EASTERN GREAT LAKES WILL PUSH INTO QUEBEC
TONIGHT...SLIDING A COLD FRNT THRU THE LOCAL AREA. AHEAD OF THE
FRNT...SCA CONDITIONS CONTINUE EVERYWHERE W/ SW WINDS 15-25 KT
GUSTING TO 30 KT. SEAS WILL BUILD TO 5-7 FT OVER THE LOWER EASTERN
SHORE COASTAL ZONES. THE FRNT SHOULD CLEAR THE WTRS BY 12Z...W/ AN
ENSUING QUICK CAA SURGE PRODUCING WINDS OCCASIONALLY UP TO GALE
FORCE. AT THIS POINT WILL STICK W/ THE CURRENT SCA IN EFFECT AND
WILL HANDLE ANY SHORT-DURATION GALE FORCE GUSTS W/ A SMW. NW WINDS
BEHIND THE FRNT WILL ALLOW SEAS OVER THE NC COASTAL ZONE TO
CONTINUE AT 4-6 FT UNTIL WED EVENG...SO WILL KEEP SCA IN EFFECT
UNTIL THEN. WINDS WILL STEADILY DIMINISH WED EVENG/NGT AS HI PRES
BLDS IN FM THE W. ANOTHER COLD FRNT CROSSES THE WTRS THU NGT
FOLLOWED BY A RETURN TO HI PRES FRI.
&&
.TIDES/COASTAL FLOODING...
ANOTHER ROUND OF BELOW NORMAL TIDES IS EXPECTED WITH THIS EVENING`S
LOW TIDE CYCLE. TIDAL LEVELS COULD REACH 1-1.5 FT BELOW MLLW.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR ANZ630>634-
650-652-654-656.
SMALL CRAFT ADVISORY UNTIL 11 PM EST WEDNESDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM/AJZ
NEAR TERM...MPR/MAM
SHORT TERM...MAM/AJZ
LONG TERM...MAS
AVIATION...JEF
MARINE...MAS
TIDES/COASTAL FLOODING...MAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
503 PM EST TUE JAN 17 2012
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW STRONG UPR
DISTURBANCE IN THE MID MS RIVER VALLEY AND ACCOMPANYING SFC LO OVER
SRN LWR MI MOVING STEADILY TO THE E. ANOTHER DISTURBANCE IS A BIT
FARTHER N OVER MN. ALTHOUGH THE SHARPER DYNAMICS/WAD/MORE
SUBSTANTIAL MSTR ASSOCIATED WITH THE SOUTHERN DISTURBANCE IS
REMAINING TO THE S...ENHANCED H4-2 DVGC OVER THE CWA IN RRQ OF UPR
JET JUST S OF JAMES BAY AND THE UPR JET TO THE S THAT IS SUPPORTING
THE SOUTHERN SHRTWV AS WELL AS SLOPED FGEN ON THE COLD SIDE SYNOPTIC
FNT TO THE SE IS PROVIDING ENUF LIFT TO OVERCOME GENERAL CAD AT H85
TO BRING A WIDESRPEAD SN. THIS PCPN IS HEAVIEST IN THE N WIND SN
BELTS NEAR LK SUP WHERE THE INCOMING AIRMASS...H85 TEMPS AOB
-15C...IS CAUSING SOME ENHANCEMENT TO THE SN WITH UNIDIRECTIONAL N
WIND SHOWN ON THE MQT VWP THRU 8K FT MSL. SPOTTER NEAR IWD REPORTED
6-8 INCHES OF SN AS OF ABOUT 1630Z. HOWEVER...LATEST RADAR TRENDS
SHOW DIMINISHING MSTR/RETURNS ARRIVING W-E AS DISTURBANCES ARE
MOVING STEADILY E IN PROGRESSIVE UPR FLOW. UPSTREAM ARCTIC AIRMASS
IN MN IS QUITE DRY/STABLE PER 12Z INL RAOB...WHERE THE 12Z H85 TEMP
WAS -19C. SFC TEMPS ARE NOT MUCH ABV ZERO F IN THIS AREA...WITH
DEWPTS WELL BLO 0F.
&&
.SHORT TERM DISCUSSION /TNGT AND WED/...
MAIN FCST CONCERNS ARE LES TRENDS/AMOUNTS AND GOING HEADLINES/NEED
TO MAKE ANY ADJUSTMENTS TO THESE.
TNGT...AS PAIR OF DISTURBANCES/UPR JETS SHIFT TO THE E...SHRTWV RDG
AXIS/DRIER AIR IS PROGGED TO FOLLOW INTO THE UPR LKS. LINGERING
SYNOPTIC PCPN SHOULD DIMINISH LATE THIS AFTN OVER THE E WITH THE
ARRIVAL OF THE DRYING ALF AND RECENT RADAR TRENDS. ALTHOUGH THE
INCOMING AIRMASS WL BE MORE THAN SUFFICIENTLY COLD FOR LES WITH H85
TEMPS FALLING TO ARND -20C...THE DRYNESS/STABILITY OF THE UPSTREAM
AIRMASS AS WELL THE STEADILY BACKING WINDS ACCOMPANYING THE MOVEMENT
OF SFC HI PRES INTO THE MID MS RIVER VALLEY BY 12Z WED WL TEND TO
LIMIT LES AMOUNTS. FCST SDNGS FOR IWD SHOW INVRN BASE SINKING TO 2K
FT AGL BY 12Z WITH A SW SFC WIND...SO LES SHOULD END ENTIRELY THERE
BY THAT TIME. LES WL BE MORE RESILIENT E OF MQT WITH LONGER FETCH...
MORE PERSISTENT LLVL CNVGC AND INVRN BASE HANGING CLOSER TO 5K FT
MOST OF THE NGT. WITH BACKING LLVL FLOW/ARRIVAL OF DRIER AIR...
EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR W HALF...WHERE SOME
CLRG IS LIKELY GIVEN DRYNESS OF UPSTREAM AIRMASS.
AS FOR HEADLINES...PLAN TO ALLOW THE GOING WRNGS/ADVYS FOR THE W TO
EXPIRE AS SCHEDULED AT 00Z. OPTED TO CANX BARAGA COUNTY WITH
UNFAVORABLE NNW FLOW...BUT EXTENDED THE MQT ADVY UNTIL 00Z TO
ACCOUNT FOR LINGERING SHSN TOWARD THE ALGER COUNTY LINE. WL LET THE
ALGER ADVY GO THRU THE NGT WITH BULK OF SHSN SHIFTING INTO THAT
AREA. CONSIDERED A HEADLINE FOR NRN SCHOOLCRAFT AND LUCE COUNTIES AS
WELL...BUT THESE AREAS MISSED OUT ON THE BULK OF THE SN TDAY. WITH
SHIFTING WINDS TNGT... SUSPECT SN TOTALS IN THIS AREA WL BE LESS
THAN THE 3-5" INDICATED BY LES CHART FOR EXPECTED CONDITIONS EVEN
THOUGH THERE MAY BE PERIODS WHERE LLVL CNVGC IS ENHANCED BY LAND
BREEZE FLOW OFF ONTARIO.
WED...NEXT SHRTWV IN PROGRESSIVE FLOW ALF IS FCST TO MOVE FM THE NRN
PLAINS TO MN BY LATE IN THE DAY...WITH DVPA/WAD/DEEP LYR QVECTOR
CNVGC ARRIVING OVER THE W IN THE AFTN IN INCRSG SLY FLOW. WITH THE
BACKING FLOW...ANY LINGERING LES OVER THE KEWEENAW AND E OF GRAND
MARAIS WL SHIFT BACK INTO LK SUP. SINCE THE LO/MID LVLS WL BE
DRY...INITIAL DYNAMICS WL RESULT IN MAINLY THICKER MID/HI CLDS. WL
RETAIN GOING POPS ONLY FOR THE FAR W. WITH THE RETURN SSW FLOW OFF
LK MI...THERE COULD BE SOME LK CLDS/SHSN THERE AS WELL. BUT AIRMASS
APPEARS TOO DRY OVERALL TO SUPPORT MORE THAN LO CHC POPS.
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
MODELS ARE IN AGREEMENT WITH THE NEXT SFC LOW TO BE POSITIONED OVER
WESTERN LS AT 00Z THURSDAY TO RESIDE OVER CENTRAL LS/CENTRAL UPPER
MI BY 06Z...AND JUST EAST OF THE CWA BY 12Z THURSDAY. THERE ARE
SMALL DIFFERENCES WHICH SHOULD BE SMOOTHED OUT WITH ANOTHER RUN OR
2. THE 17/09Z SRF WAS THE SLOWEST/MOST NW OF THE OPTIONS WHILE THE
GFS WAS THE FARTHEST SOUTH. ALL SOLUTIONS WHERE STILL UNDER THE
RHELM OF POSSIBILITY.
THE SFC LOW WILL BE ASSISTED EASTWARD BY A 500MB TROUGH SWINGING
FROM MN AT 00Z THURSDAY...SLIDING EAST OF UPPER MI BY MID MORNING
THURSDAY. EVEN THROUGH HIGH PRESSURE WILL ATTEMPT TO BUILD IN FROM
THE DAKOTAS ON THURSDAY...A TYPICIAL LINGERING SFC TROUGH CAN BE
EXPECTED OVER LAKE SUPERIOR THROUGH AT LEAST FRIDAY MORNING. THE
TROUGH SHOULD DIMINISH IN STRENGTH FRIDAY...BUT WILL QUICKLY BE
REPLACED BY ANOTHER TROUGH OUT AHEAD OF THE NEXT LOW PUSHING
EASTWARD FROM THE DAKOTAS.
THE COLDEST TEMPERATURES WILL LIKELY BE THURSDAY NIGHT INTO FRIDAY
MORNING...PARTICULARLY INTERIOR WEST IF CLOUDS CLEAR OUT AS MUCH AS
EXPECTED.
DAYS 4 THROUGH 7...SATURDAY THROUGH TUESDAY
DISAGREEMENTS REMAIN WITH THE HANDLING OF THE FEATURE FOR THIS
WEEKEND. AT 500MB THE ECMWF IS APPROX 6 HOURS QUICKER THAN THE GFS
BY SUNDAY MONRNING. ADDING TO THE ISSUES THE CANADIAN IS NEARLY FLAT
WITH THE INCOMING THROUGH...WHILE THE ECMWF/GFS SHOW SIMILAR
STRENGTH. IN SUPPORT OF THE ECMWF...THE 17/00Z ENSEMBLE RUNS OF THE
GFS WERE GENERALLY QUICKER THAN THE OPERATIONAL GFS.
LOOK FOR A DOMINANT RIDGE TO DEVELOP OVER THE CENTRAL AND SOUTHERN
PLAINS LATE IN THE WEEKEND...AND BUILD ACROSS THE UPPER GREAT LAKES
MONDAY...BEFORE SHIFTING TO THE EAST MONDAY NIGHT INTO EARLY
TUESDAY. MORE SIGNIFICANT DIFFERENCES CREEP IN MODEL WISE FOR
DAY7/TUESDAY. THE ECMWF STRENGTHENS THE 500MB TROUGH OFF THE WEST
COAST SUNDAY INTO A SIZABLE CUT OFF LOW ACROSS AZ/NM MONDAY
AFTERNOON THROUGH TUESDAY. THE GFS IS MUCH MORE PROGRESSIVE. EITHER
WAY...THE NEXT 500MB TROUGH WILL LIKELY SLIDE IN DURING THE DAY
TUESDAY.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
DRIER AIR IS BEGINNING ITS PUSH INTO IWD ATTM PER RADAR IMAGERY AND
IWD OBSERVATIONS. THIS COMBINED WITH BACKING WINDS WILL ERODE LES
AND ALLOW VIS AND CIG TO RISE THIS AFTERNOON AND EVENING. ARRIVAL OF
DRIER AIR AT CMX AND SAW IS EXPECTED AROUND 20-21Z WITH BACKING AND
STRONGER WINDS. LOW LEVEL MOISTURE SHOULD STILL REMAIN AN ISSUE AT
ALL THREE SITES THROUGH 00Z BEFORE INCREASINGLY DRY AIR REMOVES
CLOUD COVER. HOWEVER...CMX COULD SEE LOW LEVEL CLOUDS AND LIGHT SNOW
SHOWERS REMAINING OVERNIGHT WITH FAVORED WESTERLY TO NORTHWESTERLY
FLOW. ALSO...EXPECT GUSTY WINDS UP TO 25KT THROUGH THIS EVENING AT
CMX AND SAW AS STRONGER WINDS AT 2-4KFT MIX TO THE SURFACE.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT N WINDS UP TO 30 KTS EARLY THIS EVNG TO DIMINISH WITH
APPROACH OF HI PRES RIDGE FROM THE W. AS THIS HI CENTER SHIFTS TO
THE E WELL S OF THE UPPER LAKES...THE FLOW WILL ALSO BACK STEADILY
TO THE S ON WED AND INCREASE LATE IN THE DAY/EVNG AS ANOTHER LO PRES
CENTER MOVES TOWARD WESTERN LAKE SUP. ONCE THIS LO MOVES BY TO THE
E...A STRONG NW WIND WILL DRIVE BITTERLY COLD ARCTIC AIR OVER THE
AREA ON THU. THE MIXING ENHANCED BY THE CONSIDERABLE OVERWATER
INSTABILITY WILL DRAG STRONG NW WINDS TO THE SURFACE...SO MAINTAINED
GALE WATCH FOR WED NIGHT THRU THU. ALSO OPTED TO ISSUE HEAVY
FREEZING SPRAY WATCH FOR LATE WED NGT THRU THU NGT FOR ALL LK ZNS
WITH THE BITTERLY COLD AIR MOVING OVERHEAD. WINDS WILL DIMINISH AFT
THU NGT WITH WEAK PRES GRADIENT DOMINATING INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ005.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ006.
LAKE SUPERIOR...
GALE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING
FOR LSZ264-266-267.
HEAVY FREEZING SPRAY WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR LSZ264>267.
GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON FOR
LSZ162-263.
HEAVY FREEZING SPRAY WATCH FROM LATE WEDNESDAY NIGHT THROUGH
FRIDAY MORNING FOR LSZ162-263.
GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
LSZ265.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...KF
AVIATION...TK
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1242 PM EST TUE JAN 17 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(943 AM EST TUE JAN 17 2012)
LOW PRESSURE WILL BRING RAIN CHANGING TO FREEZING DRIZZLE AND THEN
SNOW TODAY. FROM 2 TO 6 INCHES OF SNOW IS EXPECTED NORTH OF
INTERSTATE 96 BY MIDNIGHT. THE EVENING COMMUTE COULD BE SLOWED BY
ICY ROADS AS TEMPERATURES DROP BELOW FREEZING THIS AFTERNOON. LAKE
EFFECT SNOW SHOWERS ARE EXPECTED OVERNIGHT AS ARCTIC AIR MOVES IN
WITH 1 TO 4 INCHES OF ADDITIONAL SNOW ALONG AND WEST OF HIGHWAY 131
BY WEDNESDAY MORNING.
&&
.SHORT TERM...(943 AM EST TUE JAN 17 2012)
(THIS AFTERNOON THROUGH THURSDAY AFTERNOON)
DROPPED THE DENSE FOG ADVISORY AS RAIN EARLIER THIS MORNING HAS
ALLOWED VISBYS TO IMPROVE. INCREASING NORTHEAST WINDS SHOULD KEEP
DENSE FOG FROM REFORMING. DROPPED MENTION OF THUNDER AS SOUTHERN
FORECAST AREA IS CURRENTLY DRY SLOTTED AND HRRR RUC SHOWS ANY
CONVECTIVE LOOKING PRECIP FORMING OFF TO THE EAST OF THE SOUTHERN
FORECAST AREA.
WILL HAVE TO CONSIDER EXPANDING THE WINTER WEATHER ADVISORY
SOUTHWARD THIS AFTERNOON AS TEMPS FALL BELOW FREEZING ALLOWING
RESIDUAL MOISTURE TO FREEZE ON ROADS...COMBINED WITH SYNOPTIC SNOWS
AND PERHAPS A PERIOD OF FREEZING RAIN OR DRIZZLE.
REST OF PREVIOUS DISCUSSION FOLLOWS.
THE LOW PRESSURE SYSTEM RESPONSIBLE FOR THIS WILL TRACK FROM NEAR
SBN AT 12Z THIS MORNING TO LAKE ONTARIO BY 00Z THIS EVE. PCPN TYPE
TODAY SHOULD BE ALL SNOW ACROSS OUR NORTHERN COUNTIES WHERE SNOW
ACCUMULATIONS OF 3 TO 6 INCHES ARE ANTICIPATED. ACROSS OUR CENTRAL
COUNTIES WE EXPECT LIGHT RAIN/DRIZZLE TO GRADUALLY TRANSITION TO
SNOW TOWARD MID TO LATE MORNING. 1 TO 3 INCHES OF SNOW IS THE MOST
LIKELY OUTCOME ACROSS THIS AREA... MAYBE LOCALLY 4 INCHES WHERE
P-TYPE TRANSITIONS TO SNOW THE SOONEST.
P-TYPE WILL GRADUALLY TRANSITION FROM RAIN TO SNOW ACROSS OUR
SOUTHERN COUNTIES FROM WNW TO ESE THIS AFTN AS SUGGESTED BY 00Z
GFS/NAM LOW LEVEL THICKNESS TOOLS. ONLY A FEW TENTHS TO AS MUCH AS 2
INCHES OF SNOW WILL FALL ACROSS OUR SOUTHERN COUNTIES THIS AFTN...
WITH LOWEST AMOUNTS OF LESS THAN AN INCH NEAR JXN... WHERE P-TYPE
WON/T CHANGE TO SNOW UNTIL MID TO LATE AFTN.
NW FLOW LES WILL DEVELOP LATE THIS AFTN/EVE AS H8 TEMPS FALL
SIGNIFICANTLY TO -16 TO -18 C BY 06Z WED. A QUICK ADDITIONAL 1 TO 4
INCHES OF LES IS ANTICIPATED FROM 00Z THRU 06Z THIS EVE... MAINLY IN
THE FAVORED NW FLOW SNOW BELT AREAS NEAR TO WEST OF US-131. THE AREA
NEAR TO SW OF A LINE FROM MKG TO AZO WILL BE FAVORED FOR LES THIS
EVE. HOWEVER LOWERING INVERSION HEIGHTS AND SFC RIDGING WILL CAUSE
SNOW SHOWERS TO ALREADY BEGIN TO WIND DOWN SLOWLY AFTER 06Z.
A HIGH PRESSURE RIDGE WILL BRING FAIR WX WEDNESDAY BEFORE SNOW
DEVELOPS WEDNESDAY NIGHT AS THE NEXT LOW PRESSURE SYSTEM AND COLD
FRONT MOVES THROUGH FROM 06Z THRU 12Z THUR. STRONG NW FLOW CAA
THURSDAY MEANS THAT TEMPS AROUND DAYBREAK WILL ONLY BE IN THE UPPER
TEENS TO LOWER 20S... WITH SLOWLY FALLING TEMPS THROUGH THE TEENS
THROUGH THE DAY. WNW LES IS ANTICIPATED THURSDAY AS H8 TEMPS PLUMMET
TO -19 TO -21 C BY 00Z FRI. SEVERAL ADDITIONAL INCHES OF SNOW ARE
ANTICIPATED THURSDAY IN FAVORED WNW FLOW SNOW BELT AREAS NEAR TO
WEST OF US-131.
&&
.LONG TERM...(400 AM EST TUE JAN 17 2012)
(THURSDAY NIGHT THROUGH MONDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE RISK FOR
ACCUMULATING SNOW FRIDAY.
MODELS ARE NOT IN VERY GOOD AGREEMENT. A WEAK MID LEVEL SHORTWAVE
WILL BE DROPPING SOUTHEASTWARD INTO THE GREAT LAKES REGION FOR
FRIDAY. AT THE SURFACE THE HIGH RES EURO KEEPS THE SURFACE LOW FAR
SOUTH OF MI. THE GFS AND NAM ARE SUPPORTING A TRACK FURTHER NORTH.
THIS MORE NORTHERN TRACK WOULD LEAD TO A BAND OF ACCUMULATING SNOW
IN SOUTHWEST MI. THE AIR IS PLENTY COLD ENOUGH TO SUPPORT LAKE
ENHANCEMENT. WILL BUMP UP POPS TO LIKELY FOR WESTERN PARTS OF MY
FORECAST AREA GIVEN THE POTENTIAL FOR SOME LAKE ENHANCEMENT.
OVERALL THE POTENTIAL FOR AN EXTENDED WARMUP IS DIMINISHING. TRENDS
SHOW THE COLDER AIR HOLDING IN PLACE LONGER. FOR THIS REASON WE
LOWERED TEMPERATURES.
&&
.AVIATION...(1242 PM EST TUE JAN 17 2012)
COLD FRONT HAS MOVES PAST ALL OF THE SITES BUT KJXN...AND SHOULD
MOVE PAST KJXN BY 20Z. WE/LL SEE A CHANGE OVER TO SNOW BY 20Z. VSBYS
WILL REMAIN AOB 1 1/2SM -SHSN FOR SEVERAL HOURS EXCEPT IN THE EAST
WHERE THEY MAY BE CLOSER TO 3SM. MVFR CONDITIONS WILL PREVAIL DURING
THE EVENING AS SOME LAKE EFFECT SNOWS DEVELOP. PCPN WILL DIMINISH
OVERNIGHT.
&&
.MARINE...(400 AM EST TUE JAN 17 2012)
GALE WARNING IN EFFECT TODAY DUE TO STRONG NW WINDS ON THE BACK SIDE
OF THE DEPARTING LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...(400 AM EST TUE JAN 17 2012)
NO ICE JAMS HAVE BEEN REPORTED. POTENTIAL FOR THEM WILL INCREASE
THIS WEEK AS COLDER AIR MOVES IN... PARTICULARLY BY THURSDAY AND
FRIDAY WHEN HIGH TEMPS WILL ONLY REACH THE 15 TO 20 DEGREE MARK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY CONTINUES IN EFFECT UNTIL 7 PM EST THIS
EVENING FOR MASON LAKE OSCEOLA CLARE OCEANA NEWAYGO MECOSTA
ISABELLA MONTCALM AND GRATIOT COUNTIES.
LM...GALE WARNING ST JOSEPH TO MANISTEE 7 AM TO 11 PM TODAY.
&&
$$
SYNOPSIS: OSTUNO
SHORT TERM: LAURENS/OSTUNO
LONG TERM: MJS
AVIATION: 93
MARINE: LAURENS
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
151 PM EST TUE JAN 17 2012
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES AND BREEZY SOUTHWEST WINDS ARE EXPECTED
THIS AFTERNOON AHEAD OF AN APPROACHING COLD FRONT. A LINE OF SHOWERS
WILL ACCOMPANY THE COLD FRONT AS IT CROSSES THE AREA OVERNIGHT.
NEAR NORMAL TEMPERATURES AND DRY CONDITIONS ARE EXPECTED IN THE WAKE
OF THE FRONT WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 AM TUESDAY...
OVERVIEW:
A ROBUST NORTHERN STREAM SHORTWAVE APPROACHING THE UPPER MS RIVER
VALLEY AS OF 15Z WILL PROGRESS INTO THE GREAT LAKES BY 00Z AND INTO
NEW ENGLAND BY 12Z WED. AN ATTENDANT 1000 MB SURFACE LOW CENTERED
OVER SOUTHERN MICHIGAN AT 15Z WILL QUICKLY DEEPEN TO 990 MB AS IT
PROGRESSES TO THE LOWER GREAT LAKES BY 00Z...AND TO 985 MB AS IT
PROGRESSES TO NORTHERN MAINE BY 12Z WED. AN ASSOCIATED COLD FRONT
WILL PROGRESS EASTWARD TO THE SOUTHERN APPALACHIANS BY 00Z...AND TO
THE CAROLINA COAST BY OR SHORTLY AFTER 12Z WED. ADDITIONAL UPPER
LEVEL ENERGY UPSTREAM OVER TX AND THE LOWER MS RIVER VALLEY AT 15Z
IS PROGGED TO PROGRESS ENE INTO THE CAROLINAS/MID-ATLANTIC OVERNIGHT.
PRECIPITATION CHANCES TODAY:
CURRENT LIGHT RAIN MOVING ACROSS THE MOUNTAINS APPEARS TO BE ASSOC/W
AN UPPER LEVEL DISTURBANCE (NOTED IN RUC H3 VORTICITY). THIS FEATURE
IS PROGGED TO PROGRESS THROUGH NORTHERN VA BY 18Z AND THEN OFFSHORE
BY 21Z. ALTHOUGH IT IS POSSIBLE THAT SOME OF THIS ACTIVITY MAY CROSS
THE MOUNTAINS AND PRODUCE A FEW SPRINKLES OR AN ISOLD SHOWER...DO
NOT ANTICIPATE MUCH IN THE WAY OF MEASURABLE PRECIP...AND WILL LEAVE
A SLIGHT CHANCE OF SPRINKLES WEST OF HWY 1 THROUGH EARLY AFTERNOON.
OTHERWISE...WITH UNIDIRECTIONAL FLOW ALOFT AND IN THE LOWER LEVELS
AND LIFT GENERALLY CONFINED TO WEAK/BROAD LOW-LEVEL WARM
ADVECTION...FEEL THAT FORCING SHOULD BE INSUFFICIENT TO WARRANT
MEASURABLE PRECIPITATION CHANCES TODAY...ALTHOUGH AN ISOLD SHOWER OR
TWO CANNOT BE RULED OUT.
PRECIPITATION CHANCES TONIGHT:
CHANCES INCREASE THIS EVENING/TONIGHT FROM THE W/NW AS THE
AFOREMENTIONED FRONTAL ZONE MOVES INTO CENTRAL NC FROM THE W/NW.
EXCELLENT LOW-LEVEL CONVERGENCE IS PROGGED IN ASSOC/W THE SFC-925 MB
TROUGH...AND SOME UPPER LEVEL SUPPORT IS EXPECTED AS SUBTLE
SHORTWAVES EMBEDDED UPSTREAM (TX/LOWER MS RIVER VALLEY) IN WSW FLOW
ALOFT PROGRESS INTO THE CAROLINAS LATER THIS EVENING/TONIGHT. THE
GFS/NAM/ECMWF ALL SHOW MEASURABLE PRECIP OVER CENTRAL NC TONIGHT.
COVERAGE IS DIFFICULT TO ASCERTAIN STILL...THOUGH...AND THE HIGH RES
WRF-NMM 1KM REFLECTIVITY PRODUCT INDICATES THAT PRECIP WILL MOST
LIKELY BE IN THE FORM OF A NARROW LINE OR BROKEN LINE OF SHOWERS
THAT DEVELOPS IN VICINITY OF THE SURFACE FRONT AS IT PROGRESSES
NW-SE THROUGH THE AREA BETWEEN ROUGHLY 03-12Z. WITH THE
AFOREMENTIONED UNCERTAINTY...WILL KEEP PRECIP CHANCES NO HIGHER THAN
60-80%...WITH THE BEST CHANCES IN THE SW PIEDMONT...SANDHILLS AND SE
COASTAL PLAIN. ALTHOUGH SFC-BASED INSTABILITY IS UNLIKELY GIVEN POOR
DIURNAL TIMING AND DEWPOINTS IN THE MID 40S THE LOWER 50S AT
BEST...STEEP MID-LEVEL LAPSE RATES WILL HELP CONTRIBUTE TO THE
POTENTIAL FOR WEAK ELEVATED INSTABILITY...AND A FEW LIGHTNING
STRIKES CANNOT BE RULED OUT IF THE CORRECT JUXTAPOSITION OF
LOWER/UPPER LEVEL FORCING OCCURS DURING FROPA.
WIND:
DUE TO A TIGHT HEIGHT/MSLP GRADIENT AHEAD OF THE FRONT AND LOW-LEVEL
TROUGH...AN IMPRESSIVE SOUTHWESTERLY LLJ WAS PRESENT THIS MORNING ON
THE 12Z RAOBS...WITH GSO/RNK REPORTING 50 KT AT H85 AND UPSTREAM
RAOBS BNA/ILN REPORTING 65-75 KT. THE 12Z GSO SOUNDING ACTUALLY
INDICATED 50 KT SW FLOW AS LOW AS 1500 FT AGL. FCST SOUNDINGS SHOW
40-50 KT FLOW AS LOW AS 2000-3000 FT AGL ACROSS CENTRAL NC THIS
AFTERNOON. LUCKILY...WIDESPREAD MID-LEVEL CLOUD COVER MOVING INTO
THE AREA FROM THE WEST WILL LIMIT DIURNAL HEATING/MIXING AND
LOW-LEVEL WARM ADVECTION SHOULD RESULT IN AN INVERSION AOA 925 MB.
THESE FACTORS SHOULD PREVENT THE TOP OF THE MIXED LAYER FROM
EXCEEDING ~2500 FT AND HELP PREVENT THE STRONGEST LOW-LEVEL FLOW
FROM MIXING DOWN. HOWEVER...UNCERTAINTY PERSISTS...AND IT IS
POSSIBLE SOME LOCATIONS COULD SEE SUSTAINED WINDS OF 25 KT AND GUSTS
UP TO 40 KT FOR A BRIEF PERIOD THIS AFTERNOON...ESPECIALLY IN THE
EAST WHERE MORE SUNSHINE THIS MORNING WILL ALLOW FOR BETTER MIXING.
WILL CONTINUE TO HIGHLIGHT THE POTENTIAL FOR GUSTY WINDS IN THE
HWO...AND WILL ISSUE AN SPS OR SHORT-FUSED WIND ADVISORY IF BREAKS
IN CLOUD COVER OR STRONGER LOW-LEVEL FLOW THAN ANTICIPATED RESULT IN
FREQUENT WIND GUSTS APPROACHING OR EXCEEDING 40 KT.
TEMPERATURES:
WITH BREEZY SOUTHWEST FLOW AND 1000-850 MB THICKNESSES PROGGED AT
~1360 METERS...EXPECT HIGHS RANGING FROM 60-68F...COOLEST NW AND
WARMEST E/SE. OVERNIGHT...LOWS WILL DEPEND PRIMARILY ON THE TIMING
OF THE FRONTAL PASSAGE AND THE COVERAGE OF SHOWER ACTIVITY PRIOR
TO/DURING FROPA. EXPECT LOWS TO RANGE FROM THE MID/UPPER 30S TO
LOWER 40S N/NW...TO MID/UPPER 40S TO LOWER 50S S/SE. -VINCENT
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 255 PM MONDAY...
FOR WEDNESDAY/WEDNESDAY NIGHT: THE NAM IS A BIT SLOWER THAN THE GFS
TO PUSH THE FRONT AND PRECIP EAST OF THE CWA WEDNESDAY MORNING...
BUT IT HAS SUPPORT FROM THE ECMWF AND WILL LEAN TOWARD THIS SOLUTION
BY RETAINING CHANCE POPS IN THE SOUTHEAST FOR A FEW HOURS IN THE
MORNING. OTHERWISE... BRISK NW WINDS WILL BRING IN MUCH COOLER AIR
THROUGH THE DAY WITH 850 MB TEMPS FALLING NEARLY 18C FROM TUESDAY
EVENING TO WEDNESDAY EVENING. TEMPS ARE LIKELY TO RISE JUST A FEW
DEGREES FROM THE FAIRLY MILD MORNING LOWS IN MOST LOCATIONS. NET
HIGHS WILL BE 44-56... ALTHOUGH IN THE SOUTHEAST CWA THESE HIGHS
WILL OCCUR IN THE MORNING WITH STEADY OR FALLING READINGS THROUGH
THE DAY. EXPECT PARTLY TO MOSTLY SUNNY SKIES AS SURFACE HIGH
PRESSURE BUILDS IN FROM THE WEST. BUT MODELS DEPICT A STRONG
VORTICITY MAX TRACKING ACROSS NC WEDNESDAY NIGHT... AND WHILE THE
COLUMN IS LIKELY TO BE TOO STABLE AND LACKING ENOUGH DEEP MOISTURE
FOR ANY PRECIP WITH THIS FEATURE... A SHOT OF MOSTLY CLOUDY SKIES IS
LIKELY. LOWS 23-28. -GIH
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 1230 PM TUESDAY...
THE OVERALL PATTERN ACROSS THE LOWER 48 WILL CONTINUE TO FEATURE ONE
THAT IS TYPICAL OF LA NINA WINTERS. OVERALL...THE TENDENCY FOR ABOVE
NORMAL HEIGHTS AND ABOVE NORMAL TEMPERATURES WILL CONTINUE FOR THE
EASTERN STATES...WITH A DEVELOPING UPPER LOW EXPECTED OVER THE
SOUTHWESTERN U.S. NEXT WEEK. MUCH ABOVE NORMAL TEMPERATURES SHOULD
VISIT OUR REGION EARLY TO MID NEXT WEEK.
WE WILL BEGIN COLD ON THURSDAY MORNING. HOWEVER...THE PROGRESSIVE
SURFACE HIGH WILL RAPIDLY MOVE OFFSHORE EARLY IN THE DAY LEADING TO
WAA. MOST MODELS GENERALLY INDICATE INCREASING CLOUDINESS WITH THE
WAA PATTERN THURSDAY WHICH WOULD LEAD TO A SLIGHT DELAY IN THE
UPCOMING WARMING TREND LATE IN THE WEEK. THURSDAY MAY END UP BEING
MUCH LIKE THIS PAST MONDAY WHEN CLOUDS RACED IN AND KEPT
TEMPERATURES MUCH COOLER THAN THEY WOULD HAVE BEEN GIVEN THE WAA
PATTERN. A SIMILAR SET UP THURSDAY SUPPORTS HIGHS THAT WILL BE
COOLER THAN MOS GUIDANCE... LEANING TOWARD THE COOLEST MET NUMBERS
IN THE 45-50 RANGE NW TO LOWER 50S SE. NOTHING MORE THAN A FEW
SPRINKLES WILL BE FORECAST WITH THE LACK OF ANY UPPER FORCING IN THE
RETURN FLOW PATTERN.
FOR THURSDAY NIGHT AND FRIDAY...ANOTHER FAST MOVING COLD FRONT IS
FORECAST TO APPROACH THE STATE THURSDAY NIGHT AND FRIDAY MORNING
WITH LITTLE MOISTURE RETURN INDICATED. PLENTY OF MID LEVEL
CLOUDINESS AND A SW BREEZE SHOULD KEEP TEMPERATURES MILD OUT AHEAD
OF THE FRONT THURSDAY NIGHT. EXPECT MOST AREAS TO SEE LOWS REMAIN IN
THE MID TO UPPER 30S. FRIDAY...A MODEST 1025 MB SURFACE HIGH IS
EXPECTED TO BUILD IN FROM THE NORTH. THIS WILL LEAD TO CAA AND
DRYING. TEMPERATURES SHOULD BE MOSTLY IN THE 50S.
FOR FRIDAY NIGHT THROUGH THE WEEKEND...A GENERALLY REPEATING PATTERN
WITH THE HIGH EXITING TO THE EAST...A WAA RETURN FLOW ESPECIALLY
SATURDAY INTO SATURDAY NIGHT. THIS WILL BE FOLLOWED BY ANOTHER FAST
MOVING LOW PRESSURE EXPECTED TO TRACK NE FROM THE TENNESSEE VALLEY
TO THE NORTHERN MID-ATLANTIC STATES AND OFFSHORE BY EARLY SUNDAY.
THE TRAILING COLD FRONT IS FORECAST TO PUSH EAST THROUGH NC BY 12Z
SUNDAY. THE HIGHEST POP SHOULD BE LATE SAT AND SAT NIGHT IN THE
WEST... AND IN THE EAST SAT NIGHT INTO EARLY SUNDAY. AFTER MORNING
LOWS IN THE 40-45 RANGE HIGHS SHOULD SOAR INTO THE 60S SATURDAY...
THEN REMAIN IN THE UPPER 40S AND 50S SATURDAY NIGHT. HIGHS SUNDAY
SHOULD BE MOSTLY IN THE 60S WITH SOME UPPER 50S NW.
MONDAY AND TUESDAY...BUILDING HEIGHTS OVER THE SE STATES COMBINED
WITH MILD PACIFIC AIR OVER THE REGION SHOULD YIELD TEMPERATURES 20
TO 25 DEGREES ABOVE NORMAL. THIS SHOULD BE MOST NOTED AT NIGHT WHEN
LOWS MAY STAY WELL IN THE 50S (NEARLY 30 DEGREES ABOVE NORMAL)...
DEPENDING ON THE AMOUNT OF CLOUDINESS. -BADGETT
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 145 PM TUESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS (ASIDE FROM ISOLD MVFR CEILINGS) ARE EXPECTED THROUGH
00Z THIS EVENING...WITH A PERIOD OF IFR (AND PERHAPS LIFR)
CONDITIONS ASSOCIATED WITH SHOWERS DEVELOPING OVERNIGHT AS A COLD
FRONT PROGRESSES THROUGH THE AREA FROM NW-SE. BREEZY SOUTHWEST WINDS
WILL OCCUR EVERYWHERE THIS AFTERNOON/EVENING AHEAD OF THE COLD
FRONT...SUSTAINED AT 15-25 KT WITH GUSTS UP TO 30-35 KT. WINDS WILL
REMAIN BREEZY AFTER SUNSET AHEAD OF THE FRONT...ALTHOUGH SUSTAINED
WIND SPEEDS/GUSTS MAY DECREASE 5-10 KT FROM PEAK AFTERNOON WINDS.
THE LATEST 12Z GUIDANCE SHOWS THE COLD FRONT PROGRESSING SOUTHEAST
THROUGH CENTRAL NC BETWEEN 06-12Z WED...FIRST AT INT/GSO...FOLLOWED
BY RDU...AND FINALLY RWI/FAY. PRECIP CHANCES AND SUB-VFR CEILINGS
WILL OCCUR PRIMARILY BEFORE THE FRONTAL PASSAGE AT INT/GSO...WHEREAS
THE REMAINING TAF SITES ARE MORE APT TO SEE THE BEST CHANCE FOR
PRECIP AND SUB-VFR CONDITIONS ALONG AND IMMEDIATELY BEHIND THE
FRONT. WINDS WILL RAPIDLY SHIFT TO THE NORTHWEST AT ~15 KT SUSTAINED
WITH GUSTS UP TO ~25 KT IN THE WAKE OF THE FRONT. VFR CONDITIONS ARE
EXPECTED TO RETURN IN THE WAKE OF THE FRONT BY OR SHORTLY AFTER 12Z
WED MORNING...WITH WINDS BECOMING NORTHERLY AT 10-15 KT BY THE END
OF THE TAF PERIOD (18Z WED).
LOOKING AHEAD:
VFR CONDITIONS WILL RULE IN THE WAKE OF THE FRONT ON WED/THU/FRI. A
LOW PRESSURE SYSTEM APPROACHING THE AREA FROM THE WEST AND A
DEVELOPING FRONTAL ZONE OVER THE CAROLINAS COULD RESULT IN SUB-VFR
CONDITIONS FRI NIGHT THROUGH THE DAY SAT AND POSSIBLY THROUGH SAT
NIGHT AS WELL. HOWEVER...A LARGE DEGREE OF UNCERTAINTY PERSISTS
W/REGARD TO THE SPECIFICS OF THIS SYSTEM. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...HARTFIELD
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1230 PM EST TUE JAN 17 2012
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES AND BREEZY SOUTHWEST WINDS ARE EXPECTED
THIS AFTERNOON AHEAD OF AN APPROACHING COLD FRONT. A LINE OF SHOWERS
WILL ACCOMPANY THE COLD FRONT AS IT CROSSES THE AREA OVERNIGHT.
NEAR NORMAL TEMPERATURES AND DRY CONDITIONS ARE EXPECTED IN THE WAKE
OF THE FRONT WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 AM TUESDAY...
OVERVIEW:
A ROBUST NORTHERN STREAM SHORTWAVE APPROACHING THE UPPER MS RIVER
VALLEY AS OF 15Z WILL PROGRESS INTO THE GREAT LAKES BY 00Z AND INTO
NEW ENGLAND BY 12Z WED. AN ATTENDANT 1000 MB SURFACE LOW CENTERED
OVER SOUTHERN MICHIGAN AT 15Z WILL QUICKLY DEEPEN TO 990 MB AS IT
PROGRESSES TO THE LOWER GREAT LAKES BY 00Z...AND TO 985 MB AS IT
PROGRESSES TO NORTHERN MAINE BY 12Z WED. AN ASSOCIATED COLD FRONT
WILL PROGRESS EASTWARD TO THE SOUTHERN APPALACHIANS BY 00Z...AND TO
THE CAROLINA COAST BY OR SHORTLY AFTER 12Z WED. ADDITIONAL UPPER
LEVEL ENERGY UPSTREAM OVER TX AND THE LOWER MS RIVER VALLEY AT 15Z
IS PROGGED TO PROGRESS ENE INTO THE CAROLINAS/MID-ATLANTIC OVERNIGHT.
PRECIPITATION CHANCES TODAY:
CURRENT LIGHT RAIN MOVING ACROSS THE MOUNTAINS APPEARS TO BE ASSOC/W
AN UPPER LEVEL DISTURBANCE (NOTED IN RUC H3 VORTICITY). THIS FEATURE
IS PROGGED TO PROGRESS THROUGH NORTHERN VA BY 18Z AND THEN OFFSHORE
BY 21Z. ALTHOUGH IT IS POSSIBLE THAT SOME OF THIS ACTIVITY MAY CROSS
THE MOUNTAINS AND PRODUCE A FEW SPRINKLES OR AN ISOLD SHOWER...DO
NOT ANTICIPATE MUCH IN THE WAY OF MEASURABLE PRECIP...AND WILL LEAVE
A SLIGHT CHANCE OF SPRINKLES WEST OF HWY 1 THROUGH EARLY AFTERNOON.
OTHERWISE...WITH UNIDIRECTIONAL FLOW ALOFT AND IN THE LOWER LEVELS
AND LIFT GENERALLY CONFINED TO WEAK/BROAD LOW-LEVEL WARM
ADVECTION...FEEL THAT FORCING SHOULD BE INSUFFICIENT TO WARRANT
MEASURABLE PRECIPITATION CHANCES TODAY...ALTHOUGH AN ISOLD SHOWER OR
TWO CANNOT BE RULED OUT.
PRECIPITATION CHANCES TONIGHT:
CHANCES INCREASE THIS EVENING/TONIGHT FROM THE W/NW AS THE
AFOREMENTIONED FRONTAL ZONE MOVES INTO CENTRAL NC FROM THE W/NW.
EXCELLENT LOW-LEVEL CONVERGENCE IS PROGGED IN ASSOC/W THE SFC-925 MB
TROUGH...AND SOME UPPER LEVEL SUPPORT IS EXPECTED AS SUBTLE
SHORTWAVES EMBEDDED UPSTREAM (TX/LOWER MS RIVER VALLEY) IN WSW FLOW
ALOFT PROGRESS INTO THE CAROLINAS LATER THIS EVENING/TONIGHT. THE
GFS/NAM/ECMWF ALL SHOW MEASURABLE PRECIP OVER CENTRAL NC TONIGHT.
COVERAGE IS DIFFICULT TO ASCERTAIN STILL...THOUGH...AND THE HIGH RES
WRF-NMM 1KM REFLECTIVITY PRODUCT INDICATES THAT PRECIP WILL MOST
LIKELY BE IN THE FORM OF A NARROW LINE OR BROKEN LINE OF SHOWERS
THAT DEVELOPS IN VICINITY OF THE SURFACE FRONT AS IT PROGRESSES
NW-SE THROUGH THE AREA BETWEEN ROUGHLY 03-12Z. WITH THE
AFOREMENTIONED UNCERTAINTY...WILL KEEP PRECIP CHANCES NO HIGHER THAN
60-80%...WITH THE BEST CHANCES IN THE SW PIEDMONT...SANDHILLS AND SE
COASTAL PLAIN. ALTHOUGH SFC-BASED INSTABILITY IS UNLIKELY GIVEN POOR
DIURNAL TIMING AND DEWPOINTS IN THE MID 40S THE LOWER 50S AT
BEST...STEEP MID-LEVEL LAPSE RATES WILL HELP CONTRIBUTE TO THE
POTENTIAL FOR WEAK ELEVATED INSTABILITY...AND A FEW LIGHTNING
STRIKES CANNOT BE RULED OUT IF THE CORRECT JUXTAPOSITION OF
LOWER/UPPER LEVEL FORCING OCCURS DURING FROPA.
WIND:
DUE TO A TIGHT HEIGHT/MSLP GRADIENT AHEAD OF THE FRONT AND LOW-LEVEL
TROUGH...AN IMPRESSIVE SOUTHWESTERLY LLJ WAS PRESENT THIS MORNING ON
THE 12Z RAOBS...WITH GSO/RNK REPORTING 50 KT AT H85 AND UPSTREAM
RAOBS BNA/ILN REPORTING 65-75 KT. THE 12Z GSO SOUNDING ACTUALLY
INDICATED 50 KT SW FLOW AS LOW AS 1500 FT AGL. FCST SOUNDINGS SHOW
40-50 KT FLOW AS LOW AS 2000-3000 FT AGL ACROSS CENTRAL NC THIS
AFTERNOON. LUCKILY...WIDESPREAD MID-LEVEL CLOUD COVER MOVING INTO
THE AREA FROM THE WEST WILL LIMIT DIURNAL HEATING/MIXING AND
LOW-LEVEL WARM ADVECTION SHOULD RESULT IN AN INVERSION AOA 925 MB.
THESE FACTORS SHOULD PREVENT THE TOP OF THE MIXED LAYER FROM
EXCEEDING ~2500 FT AND HELP PREVENT THE STRONGEST LOW-LEVEL FLOW
FROM MIXING DOWN. HOWEVER...UNCERTAINTY PERSISTS...AND IT IS
POSSIBLE SOME LOCATIONS COULD SEE SUSTAINED WINDS OF 25 KT AND GUSTS
UP TO 40 KT FOR A BRIEF PERIOD THIS AFTERNOON...ESPECIALLY IN THE
EAST WHERE MORE SUNSHINE THIS MORNING WILL ALLOW FOR BETTER MIXING.
WILL CONTINUE TO HIGHLIGHT THE POTENTIAL FOR GUSTY WINDS IN THE
HWO...AND WILL ISSUE AN SPS OR SHORT-FUSED WIND ADVISORY IF BREAKS
IN CLOUD COVER OR STRONGER LOW-LEVEL FLOW THAN ANTICIPATED RESULT IN
FREQUENT WIND GUSTS APPROACHING OR EXCEEDING 40 KT.
TEMPERATURES:
WITH BREEZY SOUTHWEST FLOW AND 1000-850 MB THICKNESSES PROGGED AT
~1360 METERS...EXPECT HIGHS RANGING FROM 60-68F...COOLEST NW AND
WARMEST E/SE. OVERNIGHT...LOWS WILL DEPEND PRIMARILY ON THE TIMING
OF THE FRONTAL PASSAGE AND THE COVERAGE OF SHOWER ACTIVITY PRIOR
TO/DURING FROPA. EXPECT LOWS TO RANGE FROM THE MID/UPPER 30S TO
LOWER 40S N/NW...TO MID/UPPER 40S TO LOWER 50S S/SE. -VINCENT
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 255 PM MONDAY...
FOR WEDNESDAY/WEDNESDAY NIGHT: THE NAM IS A BIT SLOWER THAN THE GFS
TO PUSH THE FRONT AND PRECIP EAST OF THE CWA WEDNESDAY MORNING...
BUT IT HAS SUPPORT FROM THE ECMWF AND WILL LEAN TOWARD THIS SOLUTION
BY RETAINING CHANCE POPS IN THE SOUTHEAST FOR A FEW HOURS IN THE
MORNING. OTHERWISE... BRISK NW WINDS WILL BRING IN MUCH COOLER AIR
THROUGH THE DAY WITH 850 MB TEMPS FALLING NEARLY 18C FROM TUESDAY
EVENING TO WEDNESDAY EVENING. TEMPS ARE LIKELY TO RISE JUST A FEW
DEGREES FROM THE FAIRLY MILD MORNING LOWS IN MOST LOCATIONS. NET
HIGHS WILL BE 44-56... ALTHOUGH IN THE SOUTHEAST CWA THESE HIGHS
WILL OCCUR IN THE MORNING WITH STEADY OR FALLING READINGS THROUGH
THE DAY. EXPECT PARTLY TO MOSTLY SUNNY SKIES AS SURFACE HIGH
PRESSURE BUILDS IN FROM THE WEST. BUT MODELS DEPICT A STRONG
VORTICITY MAX TRACKING ACROSS NC WEDNESDAY NIGHT... AND WHILE THE
COLUMN IS LIKELY TO BE TOO STABLE AND LACKING ENOUGH DEEP MOISTURE
FOR ANY PRECIP WITH THIS FEATURE... A SHOT OF MOSTLY CLOUDY SKIES IS
LIKELY. LOWS 23-28. -GIH
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 1230 PM TUESDAY...
THE OVERALL PATTERN ACROSS THE LOWER 48 WILL CONTINUE TO FEATURE ONE
THAT IS TYPICAL OF LA NINA WINTERS. OVERALL... THE TENDENCY FOR
ABOVE NORMAL HEIGHTS AND ABOVE NORMAL TEMPERATURES WILL CONTINUE FOR
THE EASTERN STATES... WITH A DEVELOPING UPPER LOW EXPECTED OVER THE
SOUTHWESTERN U.S. NEXT WEEK. MUCH ABOVE NORMAL TEMPERATURES SHOULD
VISIT OUR REGION EARLY TO MID NEXT WEEK.
WE WILL BEGIN COLD ON THURSDAY MORNING. HOWEVER... THE PROGRESSIVE
SURFACE HIGH WILL RAPIDLY MOVE OFFSHORE EARLY IN THE DAY LEADING TO
WAA. MOST MODELS GENERALLY INDICATE INCREASING CLOUDINESS WITH THE
WAA PATTERN THURSDAY WHICH WOULD LEAD TO A SLIGHT DELAY IN THE
UPCOMING WARMING TREND LATE IN THE WEEK. THURSDAY MAY END UP BEING
MUCH LIKE THIS PAST MONDAY WHEN CLOUDS RACED IN AND KEPT
TEMPERATURES MUCH COOLER THAN THEY WOULD HAVE BEEN GIVEN THE WAA
PATTERN. A SIMILAR SET UP THURSDAY SUPPORTS HIGHS THAT WILL BE
COOLER THAN MOS GUIDANCE... LEANING TOWARD THE COOLEST MET NUMBERS
IN THE 45-50 RANGE NW TO LOWER 50S SE. NOTHING MORE THAN A FEW
SPRINKLES WILL BE FORECAST WITH THE LACK OF ANY UPPER FORCING IN THE
RETURN FLOW PATTERN.
FOR THURSDAY NIGHT AND FRIDAY... ANOTHER FAST MOVING COLD FRONT IS
FORECAST TO APPROACH THE STATE THURSDAY NIGHT AND FRIDAY MORNING
WITH LITTLE MOISTURE RETURN INDICATED. PLENTY OF MID LEVEL
CLOUDINESS AND A SW BREEZE SHOULD KEEP TEMPERATURES MILD OUT AHEAD
OF THE FRONT THURSDAY NIGHT. EXPECT MOST AREAS TO SEE LOWS REMAIN IN
THE MID TO UPPER 30S. FRIDAY... A MODEST 1025 MB SURFACE HIGH IS
EXPECTED TO BUILD IN FROM THE NORTH. THIS WILL LEAD TO CAA AND
DRYING. TEMPERATURES SHOULD BE MOSTLY IN THE 50S.
FOR FRIDAY NIGHT THROUGH THE WEEKEND... A GENERALLY REPEATING
PATTERN WITH THE HIGH EXITING TO THE EAST... A WAA RETURN FLOW
ESPECIALLY SATURDAY INTO SATURDAY NIGHT. THIS WILL BE FOLLOWED BY
ANOTHER FAST MOVING LOW PRESSURE EXPECTED TO TRACK NE FROM THE
TENNESSEE VALLEY TO THE NORTHERN MID-ATLANTIC STATES AND OFFSHORE BY
EARLY SUNDAY. THE TRAILING COLD FRONT IS FORECAST TO PUSH EAST
THROUGH NC BY 12Z SUNDAY. THE HIGHEST POP SHOULD BE LATE SAT AND SAT
NIGHT IN THE WEST... AND IN THE EAST SAT NIGHT INTO EARLY SUNDAY.
AFTER MORNING LOWS IN THE 40-45 RANGE HIGHS SHOULD SOAR INTO THE 60S
SATURDAY... THEN REMAIN IN THE UPPER 40S AND 50S SATURDAY NIGHT.
HIGHS SUNDAY SHOULD BE MOSTLY IN THE 60S WITH SOME UPPER 50S NW.
MONDAY AND TUESDAY... BUILDING HEIGHTS OVER THE SE STATES COMBINED
WITH MILD PACIFIC AIR OVER THE REGION SHOULD YIELD TEMPERATURES 20
TO 25 DEGREES ABOVE NORMAL. THIS SHOULD BE MOST NOTED AT NIGHT WHEN
LOWS MAY STAY WELL IN THE 50S (NEARLY 30 DEGREES ABOVE NORMAL)...
DEPENDING ON THE AMOUNT OF CLOUDINESS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 645 AM TUESDAY...
MAINLY VFR CONDITIONS WILL HOLD OVER MUCH OF CENTRAL NC THROUGH
14Z... ALTHOUGH MVFR CIGS WILL LINGER AT INT/GSO DURING THIS TIME...
BEFORE LIFTING AND MIXING OUT BY 15Z. OTHERWISE... SCT-BKN CLOUDS AT
3500-5000 FT AGL AND BKN MID CLOUDS BASED ABOVE 8 KFT WILL PERSIST
THROUGH THIS MORNING AND AFTERNOON. OF CONCERN ARE THE STRONG SW
WINDS... EXPECTED TO BE SUSTAINED AT 12-20 KTS AND GUSTING TO 24-30
KTS FROM SHORTLY BEFORE DAYBREAK THIS MORNING THROUGH THE DAY...
WITH ONLY MINOR ABATEMENT THIS EVENING. WHILE LOW LEVEL WIND SHEAR
CRITERIA ARE UNLIKELY TO BE MET... SW WINDS WILL INCREASE WITH
HEIGHT (AND VEER SLIGHTLY) THROUGH THE LOWEST 5 KFT... POTENTIALLY
REACHING 50 KT AT 4-5 KFT... WHICH MAY PRODUCE MECHANICAL TURBULENCE
AND DIFFICULTY IN AIRCRAFT HANDLING. AFTER SUNSET THIS EVENING... AS
A COLD FRONT APPROACHES FROM THE NW... CIGS ARE EXPECTED TO DROP TO
MVFR WITH AREAS OF RAIN NEARING INT/GSO TOWARD 03Z-06Z... AND INTO
RDU/RWI/FAY BETWEEN 06Z-09Z LASTING UNTIL THE END OF THE TAF VALID
PERIOD (12Z). IFR CONDITIONS ARE LIKELY DURING PERIODS OF STEADY
RAIN. THE MVFR/IFR CONDITIONS WILL EXIT INT/GSO 10Z-12Z.
LOOKING BEYOND 12Z WEDNESDAY MORNING: MVFR TO BRIEFLY IFR CONDITIONS
WITH BLUSTERY SW WINDS AND AREAS OF RAIN WILL HOLD THROUGH 13Z (RDU)
TO 15Z (RWI/FAY)... WHEN COLD FRONT PASSAGE WILL DRAMATICALLY SHIFT
WINDS AROUND TO BRISK NORTHWESTERLY AS COLD AIR RUSHES IN. SKIES
WILL BE MOSTLY SUNNY WEDNESDAY AFTERNOON EXCEPT FOR PATCHES OF
CLOUDS BASED ABOVE 4 KFT AGL. VFR CONDITIONS WILL HOLD THROUGH
FRIDAY... THEN ANOTHER STORM SYSTEM WILL APPROACH FROM THE WEST
FRIDAY NIGHT... BRINGING POSSIBLE MVFR/IFR CONDITIONS LATE FRIDAY
NIGHT THROUGH SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...HARTFIELD
LONG TERM...BADGETT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1118 AM EST TUE JAN 17 2012
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES AND BREEZY SOUTHWEST WINDS ARE EXPECTED
THIS AFTERNOON AHEAD OF AN APPROACHING COLD FRONT. A LINE OF SHOWERS
WILL ACCOMPANY THE COLD FRONT AS IT CROSSES THE AREA OVERNIGHT.
NEAR NORMAL TEMPERATURES AND DRY CONDITIONS ARE EXPECTED IN THE WAKE
OF THE FRONT WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 AM TUESDAY...
OVERVIEW:
A ROBUST NORTHERN STREAM SHORTWAVE APPROACHING THE UPPER MS RIVER
VALLEY AS OF 15Z WILL PROGRESS INTO THE GREAT LAKES BY 00Z AND INTO
NEW ENGLAND BY 12Z WED. AN ATTENDANT 1000 MB SURFACE LOW CENTERED
OVER SOUTHERN MICHIGAN AT 15Z WILL QUICKLY DEEPEN TO 990 MB AS IT
PROGRESSES TO THE LOWER GREAT LAKES BY 00Z...AND TO 985 MB AS IT
PROGRESSES TO NORTHERN MAINE BY 12Z WED. AN ASSOCIATED COLD FRONT
WILL PROGRESS EASTWARD TO THE SOUTHERN APPALACHIANS BY 00Z...AND TO
THE CAROLINA COAST BY OR SHORTLY AFTER 12Z WED. ADDITIONAL UPPER
LEVEL ENERGY UPSTREAM OVER TX AND THE LOWER MS RIVER VALLEY AT 15Z
IS PROGGED TO PROGRESS ENE INTO THE CAROLINAS/MID-ATLANTIC OVERNIGHT.
PRECIPITATION CHANCES TODAY:
CURRENT LIGHT RAIN MOVING ACROSS THE MOUNTAINS APPEARS TO BE ASSOC/W
AN UPPER LEVEL DISTURBANCE (NOTED IN RUC H3 VORTICITY). THIS FEATURE
IS PROGGED TO PROGRESS THROUGH NORTHERN VA BY 18Z AND THEN OFFSHORE
BY 21Z. ALTHOUGH IT IS POSSIBLE THAT SOME OF THIS ACTIVITY MAY CROSS
THE MOUNTAINS AND PRODUCE A FEW SPRINKLES OR AN ISOLD SHOWER...DO
NOT ANTICIPATE MUCH IN THE WAY OF MEASURABLE PRECIP...AND WILL LEAVE
A SLIGHT CHANCE OF SPRINKLES WEST OF HWY 1 THROUGH EARLY AFTERNOON.
OTHERWISE...WITH UNIDIRECTIONAL FLOW ALOFT AND IN THE LOWER LEVELS
AND LIFT GENERALLY CONFINED TO WEAK/BROAD LOW-LEVEL WARM
ADVECTION...FEEL THAT FORCING SHOULD BE INSUFFICIENT TO WARRANT
MEASURABLE PRECIPITATION CHANCES TODAY...ALTHOUGH AN ISOLD SHOWER OR
TWO CANNOT BE RULED OUT.
PRECIPITATION CHANCES TONIGHT:
CHANCES INCREASE THIS EVENING/TONIGHT FROM THE W/NW AS THE
AFOREMENTIONED FRONTAL ZONE MOVES INTO CENTRAL NC FROM THE W/NW.
EXCELLENT LOW-LEVEL CONVERGENCE IS PROGGED IN ASSOC/W THE SFC-925 MB
TROUGH...AND SOME UPPER LEVEL SUPPORT IS EXPECTED AS SUBTLE
SHORTWAVES EMBEDDED UPSTREAM (TX/LOWER MS RIVER VALLEY) IN WSW FLOW
ALOFT PROGRESS INTO THE CAROLINAS LATER THIS EVENING/TONIGHT. THE
GFS/NAM/ECMWF ALL SHOW MEASURABLE PRECIP OVER CENTRAL NC TONIGHT.
COVERAGE IS DIFFICULT TO ASCERTAIN STILL...THOUGH...AND THE HIGH RES
WRF-NMM 1KM REFLECTIVITY PRODUCT INDICATES THAT PRECIP WILL MOST
LIKELY BE IN THE FORM OF A NARROW LINE OR BROKEN LINE OF SHOWERS
THAT DEVELOPS IN VICINITY OF THE SURFACE FRONT AS IT PROGRESSES
NW-SE THROUGH THE AREA BETWEEN ROUGHLY 03-12Z. WITH THE
AFOREMENTIONED UNCERTAINTY...WILL KEEP PRECIP CHANCES NO HIGHER THAN
60-80%...WITH THE BEST CHANCES IN THE SW PIEDMONT...SANDHILLS AND SE
COASTAL PLAIN. ALTHOUGH SFC-BASED INSTABILITY IS UNLIKELY GIVEN POOR
DIURNAL TIMING AND DEWPOINTS IN THE MID 40S THE LOWER 50S AT
BEST...STEEP MID-LEVEL LAPSE RATES WILL HELP CONTRIBUTE TO THE
POTENTIAL FOR WEAK ELEVATED INSTABILITY...AND A FEW LIGHTNING
STRIKES CANNOT BE RULED OUT IF THE CORRECT JUXTAPOSITION OF
LOWER/UPPER LEVEL FORCING OCCURS DURING FROPA.
WIND:
DUE TO A TIGHT HEIGHT/MSLP GRADIENT AHEAD OF THE FRONT AND LOW-LEVEL
TROUGH...AN IMPRESSIVE SOUTHWESTERLY LLJ WAS PRESENT THIS MORNING ON
THE 12Z RAOBS...WITH GSO/RNK REPORTING 50 KT AT H85 AND UPSTREAM
RAOBS BNA/ILN REPORTING 65-75 KT. THE 12Z GSO SOUNDING ACTUALLY
INDICATED 50 KT SW FLOW AS LOW AS 1500 FT AGL. FCST SOUNDINGS SHOW
40-50 KT FLOW AS LOW AS 2000-3000 FT AGL ACROSS CENTRAL NC THIS
AFTERNOON. LUCKILY...WIDESPREAD MID-LEVEL CLOUD COVER MOVING INTO
THE AREA FROM THE WEST WILL LIMIT DIURNAL HEATING/MIXING AND
LOW-LEVEL WARM ADVECTION SHOULD RESULT IN AN INVERSION AOA 925 MB.
THESE FACTORS SHOULD PREVENT THE TOP OF THE MIXED LAYER FROM
EXCEEDING ~2500 FT AND HELP PREVENT THE STRONGEST LOW-LEVEL FLOW
FROM MIXING DOWN. HOWEVER...UNCERTAINTY PERSISTS...AND IT IS
POSSIBLE SOME LOCATIONS COULD SEE SUSTAINED WINDS OF 25 KT AND GUSTS
UP TO 40 KT FOR A BRIEF PERIOD THIS AFTERNOON...ESPECIALLY IN THE
EAST WHERE MORE SUNSHINE THIS MORNING WILL ALLOW FOR BETTER MIXING.
WILL CONTINUE TO HIGHLIGHT THE POTENTIAL FOR GUSTY WINDS IN THE
HWO...AND WILL ISSUE AN SPS OR SHORT-FUSED WIND ADVISORY IF BREAKS
IN CLOUD COVER OR STRONGER LOW-LEVEL FLOW THAN ANTICIPATED RESULT IN
FREQUENT WIND GUSTS APPROACHING OR EXCEEDING 40 KT.
TEMPERATURES:
WITH BREEZY SOUTHWEST FLOW AND 1000-850 MB THICKNESSES PROGGED AT
~1360 METERS...EXPECT HIGHS RANGING FROM 60-68F...COOLEST NW AND
WARMEST E/SE. OVERNIGHT...LOWS WILL DEPEND PRIMARILY ON THE TIMING
OF THE FRONTAL PASSAGE AND THE COVERAGE OF SHOWER ACTIVITY PRIOR
TO/DURING FROPA. EXPECT LOWS TO RANGE FROM THE MID/UPPER 30S TO
LOWER 40S N/NW...TO MID/UPPER 40S TO LOWER 50S S/SE. -VINCENT
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 255 PM MONDAY...
FOR WEDNESDAY/WEDNESDAY NIGHT: THE NAM IS A BIT SLOWER THAN THE GFS
TO PUSH THE FRONT AND PRECIP EAST OF THE CWA WEDNESDAY MORNING...
BUT IT HAS SUPPORT FROM THE ECMWF AND WILL LEAN TOWARD THIS SOLUTION
BY RETAINING CHANCE POPS IN THE SOUTHEAST FOR A FEW HOURS IN THE
MORNING. OTHERWISE... BRISK NW WINDS WILL BRING IN MUCH COOLER AIR
THROUGH THE DAY WITH 850 MB TEMPS FALLING NEARLY 18C FROM TUESDAY
EVENING TO WEDNESDAY EVENING. TEMPS ARE LIKELY TO RISE JUST A FEW
DEGREES FROM THE FAIRLY MILD MORNING LOWS IN MOST LOCATIONS. NET
HIGHS WILL BE 44-56... ALTHOUGH IN THE SOUTHEAST CWA THESE HIGHS
WILL OCCUR IN THE MORNING WITH STEADY OR FALLING READINGS THROUGH
THE DAY. EXPECT PARTLY TO MOSTLY SUNNY SKIES AS SURFACE HIGH
PRESSURE BUILDS IN FROM THE WEST. BUT MODELS DEPICT A STRONG
VORTICITY MAX TRACKING ACROSS NC WEDNESDAY NIGHT... AND WHILE THE
COLUMN IS LIKELY TO BE TOO STABLE AND LACKING ENOUGH DEEP MOISTURE
FOR ANY PRECIP WITH THIS FEATURE... A SHOT OF MOSTLY CLOUDY SKIES IS
LIKELY. LOWS 23-28. -GIH
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 310 AM TUESDAY...
THE LATTER PART OF THE WEEK WILL FEATURE A BROAD CYCLONIC OR NEARLY
ZONAL FLOW ALOFT AS A SERIES OF LOW AMPLITUDE SHORTWAVES PASS
QUICKLY ACROSS THE NORTHERN HALF OF THE CONUS. A SURFACE HIGH
PRESSURE RIDGE WILL MOVE QUICKLY ACROSS NC ON THURSDAY...AS A LOW
PRESSURE SYSTEM SKIRTS THE GREAT LAKES AND THE TRAILING COLD FRONT
DROPPING INTO MID ATLANTIC REGION THURSDAY NIGHT. THE CANADIAN
HIGH PRESSURE BEHIND THE COLD FRONT IS FORECAST TO WEAKEN RAPIDLY
ACROSS THE MIDWEST STATES...THEN SET UP OVER NEW ENGLAND. THERE IS
SOME UNCERTAINTY AS TO HOW QUICKLY THE FRONT MAY SLIP SOUTH INTO
CENTRAL NC ON FRIDAY...IF AT ALL...WITH THE GFS BEING THE MORE
AGGRESSIVE OF THE MEDIUM RANGE MODELS. A STRONGER NORTHERN STREAM
SHORTWAVE IS THEN PROGGED TO CROSS THE MID MS VALLEY REGION FRIDAY
NIGHT AND ENHANCE SOUTHERLY RETURN FLOW AND SHOWER ACTIVITY ALONG
THE FRONTAL ZONE ON SATURDAY. WILL MAINTAIN THE CURRENT 40 PERCENT
POP ON SATURDAY UNTIL THE GFS AND ECMWF SHOW BETTER AGREEMENT ON THE
POSITION AND TIMING PRECIP AND AND A POSSIBLE COLD FRONT
SATURDAY/SATURDAY NIGHT. MODELS THEN DIVERGE MORE SIGNIFICANTLY FROM
SUNDAY ONWARD AS CUTOFF ENERGY OVER THE CALIFORNIA BAJA INTERACTS
WITH MORE SIGNIFICANT ENERGY MAKING LANDFALL ALONG THE NORTHERN
CALIFORNIA COAST. AT THAT POINT...THERE IS LITTLE CONFIDENCE IN
MODEL FORECASTS...BUT THE NEXT CHANCE FOR PRECIP SHOULD HOLD OFF
UNTIL AFTER MONDAY AS THE FLOW BEGINS TO AMPLIFY A BIT MORE.
TEMPS THROUGH THE WEEKEND SHOULD SHOW A SLOW MODERATION FROM MID
AND UPPER 40S THURSDAY TOWARD THE UPPER 50S TO AROUND 60 ON
SATURDAY. DESPITE 1000-850MB THICKNESSES FORECAST TO PEAK NEAR
1365M BY THE END OF THE WEEKEND...WILL KEEP HIGHS BELOW THEIR FULL
POTENTIAL SINCE THEIR WILL LIKELY BE PERIODS OF WIDESPREAD CLOUD
COVER...WITH HIGHS CREEPING UP THROUGH THE 60S SUNDAY AND MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 645 AM TUESDAY...
MAINLY VFR CONDITIONS WILL HOLD OVER MUCH OF CENTRAL NC THROUGH
14Z... ALTHOUGH MVFR CIGS WILL LINGER AT INT/GSO DURING THIS TIME...
BEFORE LIFTING AND MIXING OUT BY 15Z. OTHERWISE... SCT-BKN CLOUDS AT
3500-5000 FT AGL AND BKN MID CLOUDS BASED ABOVE 8 KFT WILL PERSIST
THROUGH THIS MORNING AND AFTERNOON. OF CONCERN ARE THE STRONG SW
WINDS... EXPECTED TO BE SUSTAINED AT 12-20 KTS AND GUSTING TO 24-30
KTS FROM SHORTLY BEFORE DAYBREAK THIS MORNING THROUGH THE DAY...
WITH ONLY MINOR ABATEMENT THIS EVENING. WHILE LOW LEVEL WIND SHEAR
CRITERIA ARE UNLIKELY TO BE MET... SW WINDS WILL INCREASE WITH
HEIGHT (AND VEER SLIGHTLY) THROUGH THE LOWEST 5 KFT... POTENTIALLY
REACHING 50 KT AT 4-5 KFT... WHICH MAY PRODUCE MECHANICAL TURBULENCE
AND DIFFICULTY IN AIRCRAFT HANDLING. AFTER SUNSET THIS EVENING... AS
A COLD FRONT APPROACHES FROM THE NW... CIGS ARE EXPECTED TO DROP TO
MVFR WITH AREAS OF RAIN NEARING INT/GSO TOWARD 03Z-06Z... AND INTO
RDU/RWI/FAY BETWEEN 06Z-09Z LASTING UNTIL THE END OF THE TAF VALID
PERIOD (12Z). IFR CONDITIONS ARE LIKELY DURING PERIODS OF STEADY
RAIN. THE MVFR/IFR CONDITIONS WILL EXIT INT/GSO 10Z-12Z.
LOOKING BEYOND 12Z WEDNESDAY MORNING: MVFR TO BRIEFLY IFR CONDITIONS
WITH BLUSTERY SW WINDS AND AREAS OF RAIN WILL HOLD THROUGH 13Z (RDU)
TO 15Z (RWI/FAY)... WHEN COLD FRONT PASSAGE WILL DRAMATICALLY SHIFT
WINDS AROUND TO BRISK NORTHWESTERLY AS COLD AIR RUSHES IN. SKIES
WILL BE MOSTLY SUNNY WEDNESDAY AFTERNOON EXCEPT FOR PATCHES OF
CLOUDS BASED ABOVE 4 KFT AGL. VFR CONDITIONS WILL HOLD THROUGH
FRIDAY... THEN ANOTHER STORM SYSTEM WILL APPROACH FROM THE WEST
FRIDAY NIGHT... BRINGING POSSIBLE MVFR/IFR CONDITIONS LATE FRIDAY
NIGHT THROUGH SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...HARTFIELD
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
448 PM EST TUE JAN 17 2012
.SYNOPSIS...
LOW PRESSURE OVER SOUTHERN LAKE HURON THIS AFTERNOON WILL STRENGTHEN
AS IT LIFTS NORTHEAST ACROSS THE LOWER GREAT LAKES AND DOWN
THE SAINT LAWRENCE RIVER VALLEY LATE TODAY AND TONIGHT. A SHARP COLD
FRONT TRAILING SOUTH FROM THIS LOW WILL SWEEP ACROSS THE
COMMONWEALTH EARLY TONIGHT...FOLLOWED BY A SURGE OF COLDER AIR AND
STRONG GUSTY WINDS. HIGH PRESSURE WILL MOVE INTO THE REGION LATER
WEDNESDAY INTO EARLY THURSDAY. A PAIR OF UPPER AIR DISTURBANCES AND
WEAK SURFACE LOWS SHOULD BRING A FEW PERIODS OF MAINLY LIGHT SNOW TO
THE REGION THURSDAY AFTERNOON AND NIGHT...AND AGAIN LATE FRIDAY
NIGHT INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
EXTREMELY STRONG 60-70KT 925-850 SWRLY LLJ WAS LIFTING NE ACROSS WRN
PENN AHEAD OF A DEEPENING AREA OF LOW PRESSURE CURRENTLY SITUATED
ACROSS THE SOUTHERN TIP OF LAKE HURON.
MOVED UP THE WIND ADVISORY BY 5 HOURS TO ACCOUNT FOR THIS STRONG
WIND IMPACT TO THE RIDGE TOPS OF THE LAURELS THIS AFTERNOON...AND
MAINTAINED THE PREVIOUS WIND ADVISORY FOR THE REST OF THE WESTERN
MTNS THIS EVENING INTO EARLY WEDNESDAY MORNING IN THE WAKE OF A
STRONG COLD FRONT.
FAST MOVING SHOWERS OF RAIN /ENE AT 60 KTS/ AND EVEN A FEW BREAKS IN
THE LAYERED CLOUD DECK WILL OCCUR IN THE STRONG/DEEP WSWRLY FLOW
AHEAD OF THE SFC COLD FRONT. THIS FRONT EXTENDED FROM JUST EAST OF
TOLEDO OHIO...TO WILMINGTON OHIO AT 1930Z AND WAS MOVING QUICKLY TO
THE EAST AT 40KT.
LINEAR EXTRAPOLATION BRINGS THE FRONT INTO WARREN COUNTY BETWEEN
23-00Z...AND AROUND 01Z ALONG THE LENGTH OF ROUTE 219 IN WRN PENN.
THE CFRONT WITH A LIKELY BAND OF GUSTY MDT TO BRIEFLY HEAVY RAIN
SHOWERS WILL REACH THE LOWER SUSQ VALLEY AROUND 03-04Z.
ELEVATED...925-850 MB LIFTED INDICES VIA THE RUC DROP TO NEAR...OR
SLIGHTLY BELOW ZERO ACROSS FAR SCENT PENN AND LOWER SUSQ VALLEY LATE
TODAY AND THIS EVENING. THIS MARGINAL INSTABILITY COULD SUPPORT A
FEW RUMBLES OF THUNDER ALONG THE COLD FRONTAL BOUNDARY.
VERY MILD TEMPS IN THE 40S...TO LOWER AND MID 50S IN THE SOUTH WILL
PLUMMET IN THE WAKE OF THE FRONT. THE MUCH COLDER TEMPS IN THE TEENS
/NW/...AND 20S SE WED MORNING WILL COMBINE WITH THE STRONG WESTERLY
WINDS TO BRING WIND CHILLS IN THE SINGLE DIGITS /NW/ TO TEENS /SE/.
ADDITIONAL RAINFALL LATE THIS AFTERNOON AND TONIGHT WILL AVERAGE
0.10-0.25 OF AN INCH.
RAIN SHOWERS WILL MIX WITH THEN CHANGE TO FREQUENT SHSN ACROSS THE
NW MTNS LATE THIS EVENING...WITH ACCUMULATING LES BANDS PUSHING
GRADUALLY INLAND FROM THE ERIE LAKE SHORE BY SHORTLY AFTER
MIDNIGHT.
THE BASE OF THE SUBSIDENCE INVERSION RISES TO 7-8 KFT AGL LATE
TONIGHT AND EARLY WEDNESDAY...AND A DECENT CROSS-HAIR SIGNATURE OF
UVVEL WITH THE PRIME THERMAL RIBBON FOR DENDRITIC GROWTH OCCURS
BETWEEN ABOUT 09Z AND 15Z WED...AND THAT/S WHEN THE MOST PERSISTENT
LES IS EXPECTED. RECENTLY ISSUED A LES ADVISORY FOR WARREN CTY
/MAINLY THE NW 1/3 OF THE CTY/ FROM 1 AM WED TO 4 PM WED FOR A
GENERAL 3-5 INCHES OF WIND WHIPPED SNOW AND OCNL VERY POOR VSBYS
VARIABLE AMOUNTS OF CLOUDS AND WINDY CONDITIONS WITH JUST SOME
FLURRIES WILL AFFECT THE CENTRAL RIDGE AND VALLEY REGION DURING THE
DAY WED. TEMP CURVE WILL BE VERY FLAT WEDNESDAY UNDER STRONG LLVL
COLD ADVECTION. MAX TEMPS AROUND 20F IN THE NW...AND LOWER TO MID
30S IN THE SE WILL BE JUST NEAR...TO A FEW DEG F BELOW NORMAL.
WINDS WILL RELAX BY WED AFTN AS HIGH PRES BUILDS TAKES UP BRIEF
RESIDENCE OVR PA. ANY LINGERING LAKE EFFECT OR UPSLOPE SNOW SHOWERS
SHOULD ALSO TAPER OFF THROUGHOUT THE AFTN.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
THE N-S RIDGE AXIS WILL PROVIDE A RESPITE FROM
PRECIPITATION INTO THURSDAY...WITH THE SHIFTING FLOW TO THE
NORTHWEST BY MIDDAY THURSDAY PROVIDING ENOUGH MOISTURE AND COLD
AIR TO BRING SCATTERED SNOW SHOWERS INTO THE NW MTNS...ESPECIALLY
WITH -13C AT 850MB. EXPECT LIGHT ACCUMULATIONS...WITH THE HEAVIEST
AMTS IN THE HIGHER TERRAIN. HIGHS WILL AVG A FEW TO SEVERAL DEGS
BELOW NORMAL WITH SEASONABLY COLD OVERNIGHT READINGS IN THE TEENS
AND 20S. SOME OF THE USUALLY COLD RURAL VLYS IN THE NRN TIER COULD
TOUCH THE SINGLE DIGITS UNDER IDEAL RADIATIONAL COOLING.
THIS CLIPPER TYPE LOW WILL MOVE QUICKLY THROUGH THURSDAY NIGHT. THE
STEADY MOVEMENT OF THIS SYSTEM SHOULD LIMIT AMTS TO BLW ADVY
CRITERIA. A REINFORCING SHOT OF COLD AIR WILL ARRIVE BEHIND THIS
SYSTEM THURSDAY NIGHT INTO FRIDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A WEAK RIDGE BUILDING OVER THE AREA FRIDAY SHOULD STIFLE ANY
PRECIPITATION...ESPECIALLY WITH THE WEAK FLOW...THOUGH EARLY IN
THE PERIOD...BEFORE 12Z...THERE COULD BE STRONG ENOUGH FLOW AND COLD
AIR THAT COULD ALLOW FOR A PERIOD OF LAKE EFFECT SNOW. TEMPERATURES
WILL BE COLD INTO SATURDAY. THE MODELS STILL COMPLETELY DISAGREE
ON THE TIMING OF THE SYSTEM PROPAGATING THROUGH THE REGION THIS
WEEKEND. THE GFS MOVES IT THROUGH MORE RAPIDLY WHERE THE EC
DEEPENS THE STRONG AND TAKES IT FURTHER TO THE SOUTH. HAVE TENDED
TOWARD THE EC..WITH MOS GUIDANCE FOR TEMPS...AS WARM AIR DOESN`T
GET HERE UNTIL SUNDAY. THE WARM AIR ADVECTION ON SUNDAY SHOULD
SEE WARMER HIGHS IN THE 40S. BASED ON THE CONSENSUS AND RECENT
TRENDS...HAVE BEST PRECIP CHANCES BY MIDDAY SATURDAY...WITH A
POSSIBILITY OF A RAIN SNOW MIX. COLDER TEMPERATURES SUGGEST MOST
ARES WILL HAVE SNOW...HOWEVER THE LOWER SUSQ REGION IS STILL UP IN
THE AIR DEPENDING ON ANY WARM AIR ALOFT. AS SUCH HAVE LEFT RAIN
AND SNOW IN THE WORDING. MAIN PRECIP CHANCES ON SUNDAY ARE IN THE
NW MTNS AND THE HIGHER ELEVATIONS. ANOTHER TROUGH COULD MOVE
THROUGH THE AREA MONDAY INTO TUESDAY....THIS LOOKS TO BE ANOTHER
FAST MOVING SYSTEM BUT WITH TIMING IN QUESTION HAVE LEFT ONLY
SLIGHT CHANCE POPS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
MINOR UPDATE TO 21Z TAF PACKAGE...MOST AREAS IN WARM AIR AND
VFR NOW. WIND SHIFT AND COLD AIR WELL TO THE WEST AT THIS POINT...
SO I SLOWED DOWN WIND SHIFT...AND ALSO MIX OF RAIN AND SNOW
FOR BFD. LINE OF SHOWERS RACING EASTWARD ACROSS NORTHERN OH
WILL BE NEAR BFD SOON.
EARLIER DISCUSSION BELOW.
AN APPROACHING LOW PRESSURE SYSTEM WILL BRING STRONG SWRLY FLOW
ALOFT...RESULTING IN CONTINUE LLWS ACROSS MOST OF CENTRAL PA THRU
THIS EVENING.
A FEW ADDITIONAL PERIODS OF RAIN SHOWERS ACCOMPANIED BY WIDESPREAD
MVFR CIGS AND MAINLY VFR VSBYS WILL OCCUR FOR THE REST OF TODAY.
AS LOW PRES CENTER TRACKS WEST OF THE STATE. LIFTING CIGS/IMPROVING
VSBYS WILL BE LIKELY ACROSS SOUTHERN PA LATE THIS AFTN/EVENING...
AS A WARM FRONT LIFTS NORTH OF THE MIDDLE SUSQ VALLEY.
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION THIS EVENING
ACCOMPANIED BY A NARROW BAND OF HEAVY SHRA /AND POSSIBLY EVEN A
RUMBLE OF THUNDER/ FOLLOWED BY WESTERLY WINDS GUSTING BETWEEN 30 AND
35KTS ACROSS MOST OF THE REGION TONIGHT AND EARLY WEDNESDAY. GUSTS
COULD BE BETWEEN 45-50 MPH ACROSS THE NW MTNS AND LAUREL HIGHLANDS.
OUTLOOK...
WED...WESTERLY WINDS - GUSTING TO 35-40KT EARLY ACROSS THE WRN MTNS.
LAKE EFFECT SNOW SHOWERS NEAR..AND TO THE WEST OF KBFD WITH OCNL IFR
CIGS AND VSBYS MAINLY IN THE MORNING. NO SIG WX EXPECTED ELSEWHERE.
THU...SHSN OR EVEN A PERIOD OF STEADY LIGHT SNOW/REDUCED VSBYS
POSS...MAINLY W MTNS.
FRI...NO SIG WX EXPECTED.
SAT...PERIODS OF LGT SNOW NW AND MIXED PRECIP SE.
SUN...NO SIGNIF WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 AM EST WEDNESDAY FOR PAZ004>006-010-011.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 4 PM EST WEDNESDAY FOR
PAZ004.
WIND ADVISORY UNTIL 6 AM EST WEDNESDAY FOR PAZ017-024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...CERU/STEINBUGL
LONG TERM...CERU
AVIATION...LAMBERT/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
401 PM EST TUE JAN 17 2012
.SYNOPSIS...
LOW PRESSURE OVER SOUTHERN LAKE HURON THIS AFTERNOON WILL STRENGTHEN
AS IT LIFTS NORTHEAST ACROSS THE LOWER GREAT LAKES AND DOWN
THE SAINT LAWRENCE RIVER VALLEY LATE TODAY AND TONIGHT. A SHARP COLD
FRONT TRAILING SOUTH FROM THIS LOW WILL SWEEP ACROSS THE
COMMONWEALTH EARLY TONIGHT...FOLLOWED BY A SURGE OF COLDER AIR AND
STRONG GUSTY WINDS. HIGH PRESSURE WILL MOVE INTO THE REGION LATER
WEDNESDAY INTO EARLY THURSDAY. A PAIR OF UPPER AIR DISTURBANCES AND
WEAK SURFACE LOWS SHOULD BRING A FEW PERIODS OF MAINLY LIGHT SNOW TO
THE REGION THURSDAY AFTERNOON AND NIGHT...AND AGAIN LATE FRIDAY
NIGHT INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
EXTREMELY STRONG 60-70KT 925-850 SWRLY LLJ WAS LIFTING NE ACROSS WRN
PENN AHEAD OF A DEEPENING AREA OF LOW PRESSURE CURRENTLY SITUATED
ACROSS THE SOUTHERN TIP OF LAKE HURON.
MOVED UP THE WIND ADVISORY BY 5 HOURS TO ACCOUNT FOR THIS STRONG
WIND IMPACT TO THE RIDGE TOPS OF THE LAURELS THIS AFTERNOON...AND
MAINTAINED THE PREVIOUS WIND ADVISORY FOR THE REST OF THE WESTERN
MTNS THIS EVENING INTO EARLY WEDNESDAY MORNING IN THE WAKE OF A
STRONG COLD FRONT.
FAST MOVING SHOWERS OF RAIN /ENE AT 60 KTS/ AND EVEN A FEW BREAKS IN
THE LAYERED CLOUD DECK WILL OCCUR IN THE STRONG/DEEP WSWRLY FLOW
AHEAD OF THE SFC COLD FRONT. THIS FRONT EXTENDED FROM JUST EAST OF
TOLEDO OHIO...TO WILMINGTON OHIO AT 1930Z AND WAS MOVING QUICKLY TO
THE EAST AT 40KT.
LINEAR EXTRAPOLATION BRINGS THE FRONT INTO WARREN COUNTY BETWEEN
23-00Z...AND AROUND 01Z ALONG THE LENGTH OF ROUTE 219 IN WRN PENN.
THE CFRONT WITH A LIKELY BAND OF GUSTY MDT TO BRIEFLY HEAVY RAIN
SHOWERS WILL REACH THE LOWER SUSQ VALLEY AROUND 03-04Z.
ELEVATED...925-850 MB LIFTED INDICES VIA THE RUC DROP TO NEAR...OR
SLIGHTLY BELOW ZERO ACROSS FAR SCENT PENN AND LOWER SUSQ VALLEY LATE
TODAY AND THIS EVENING. THIS MARGINAL INSTABILITY COULD SUPPORT A
FEW RUMBLES OF THUNDER ALONG THE COLD FRONTAL BOUNDARY.
VERY MILD TEMPS IN THE 40S...TO LOWER AND MID 50S IN THE SOUTH WILL
PLUMMET IN THE WAKE OF THE FRONT. THE MUCH COLDER TEMPS IN THE TEENS
/NW/...AND 20S SE WED MORNING WILL COMBINE WITH THE STRONG WESTERLY
WINDS TO BRING WIND CHILLS IN THE SINGLE DIGITS /NW/ TO TEENS /SE/.
ADDITIONAL RAINFALL LATE THIS AFTERNOON AND TONIGHT WILL AVERAGE
0.10-0.25 OF AN INCH.
RAIN SHOWERS WILL MIX WITH THEN CHANGE TO FREQUENT SHSN ACROSS THE
NW MTNS LATE THIS EVENING...WITH ACCUMULATING LES BANDS PUSHING
GRADUALLY INLAND FROM THE ERIE LAKE SHORE BY SHORTLY AFTER
MIDNIGHT.
THE BASE OF THE SUBSIDENCE INVERSION RISES TO 7-8 KFT AGL LATE
TONIGHT AND EARLY WEDNESDAY...AND A DECENT CROSS-HAIR SIGNATURE OF
UVVEL WITH THE PRIME THERMAL RIBBON FOR DENDRITIC GROWTH OCCURS
BETWEEN ABOUT 09Z AND 15Z WED...AND THAT/S WHEN THE MOST PERSISTENT
LES IS EXPECTED. RECENTLY ISSUED A LES ADVISORY FOR WARREN CTY
/MAINLY THE NW 1/3 OF THE CTY/ FROM 1 AM WED TO 4 PM WED FOR A
GENERAL 3-5 INCHES OF WIND WHIPPED SNOW AND OCNL VERY POOR VSBYS
VARIABLE AMOUNTS OF CLOUDS AND WINDY CONDITIONS WITH JUST SOME
FLURRIES WILL AFFECT THE CENTRAL RIDGE AND VALLEY REGION DURING THE
DAY WED. TEMP CURVE WILL BE VERY FLAT WEDNESDAY UNDER STRONG LLVL
COLD ADVECTION. MAX TEMPS AROUND 20F IN THE NW...AND LOWER TO MID
30S IN THE SE WILL BE JUST NEAR...TO A FEW DEG F BELOW NORMAL.
WINDS WILL RELAX BY WED AFTN AS HIGH PRES BUILDS TAKES UP BRIEF
RESIDENCE OVR PA. ANY LINGERING LAKE EFFECT OR UPSLOPE SNOW SHOWERS
SHOULD ALSO TAPER OFF THROUGHOUT THE AFTN.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
THE N-S RIDGE AXIS WILL PROVIDE A RESPITE FROM
PRECIPITATION INTO THURSDAY...WITH THE SHIFTING FLOW TO THE
NORTHWEST BY MIDDAY THURSDAY PROVIDING ENOUGH MOISTURE AND COLD
AIR TO BRING SCATTERED SNOW SHOWERS INTO THE NW MTNS...ESPECIALLY
WITH -13C AT 850MB. EXPECT LIGHT ACCUMULATIONS...WITH THE HEAVIEST
AMTS IN THE HIGHER TERRAIN. HIGHS WILL AVG A FEW TO SEVERAL DEGS
BELOW NORMAL WITH SEASONABLY COLD OVERNIGHT READINGS IN THE TEENS
AND 20S. SOME OF THE USUALLY COLD RURAL VLYS IN THE NRN TIER COULD
TOUCH THE SINGLE DIGITS UNDER IDEAL RADIATIONAL COOLING.
THIS CLIPPER TYPE LOW WILL MOVE QUICKLY THROUGH THURSDAY NIGHT. THE
STEADY MOVEMENT OF THIS SYSTEM SHOULD LIMIT AMTS TO BLW ADVY
CRITERIA. A REINFORCING SHOT OF COLD AIR WILL ARRIVE BEHIND THIS
SYSTEM THURSDAY NIGHT INTO FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A WEAK RIDGE BUILDING OVER THE AREA FRIDAY SHOULD STIFLE ANY
PRECIPITATION...ESPECIALLY WITH THE WEAK FLOW...THOUGH EARLY IN
THE PERIOD...BEFORE 12Z...THERE COULD BE STRONG ENOUGH FLOW AND COLD
AIR THAT COULD ALLOW FOR A PERIOD OF LAKE EFFECT SNOW. TEMPERATURES
WILL BE COLD INTO SATURDAY. THE MODELS STILL COMPLETELY DISAGREE
ON THE TIMING OF THE SYSTEM PROPAGATING THROUGH THE REGION THIS
WEEKEND. THE GFS MOVES IT THROUGH MORE RAPIDLY WHERE THE EC
DEEPENS THE STRONG AND TAKES IT FURTHER TO THE SOUTH. HAVE TENDED
TOWARD THE EC..WITH MOS GUIDANCE FOR TEMPS...AS WARM AIR DOESN`T
GET HERE UNTIL SUNDAY. THE WARM AIR ADVECTION ON SUNDAY SHOULD
SEE WARMER HIGHS IN THE 40S. BASED ON THE CONSENSUS AND RECENT
TRENDS...HAVE BEST PRECIP CHANCES BY MIDDAY SATURDAY...WITH A
POSSIBILITY OF A RAIN SNOW MIX. COLDER TEMPERATURES SUGGEST MOST
ARES WILL HAVE SNOW...HOWEVER THE LOWER SUSQ REGION IS STILL UP IN
THE AIR DEPENDING ON ANY WARM AIR ALOFT. AS SUCH HAVE LEFT RAIN
AND SNOW IN THE WORDING. MAIN PRECIP CHANCES ON SUNDAY ARE IN THE
NW MTNS AND THE HIGHER ELEVATIONS. ANOTHER TROUGH COULD MOVE
THROUGH THE AREA MONDAY INTO TUESDAY....THIS LOOKS TO BE ANOTHER
FAST MOVING SYSTEM BUT WITH TIMING IN QUESTION HAVE LEFT ONLY
SLIGHT CHANCE POPS.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
AN APPROACHING LOW PRESSURE SYSTEM WILL BRING STRONG SWRLY FLOW
ALOFT...RESULTING IN CONTINUE LLWS ACROSS MOST OF CENTRAL PA THRU
THIS EVENING.
A FEW ADDITIONAL PERIODS OF RAIN SHOWERS ACCOMPANIED BY WIDESPREAD
MVFR CIGS AND MAINLY VFR VSBYS WILL OCCUR FOR THE REST OF TODAY.
AS LOW PRES CENTER TRACKS WEST OF THE STATE. LIFTING CIGS/IMPROVING
VSBYS WILL BE LIKELY ACROSS SOUTHERN PA LATE THIS AFTN/EVENING...
AS A WARM FRONT LIFTS NORTH OF THE MIDDLE SUSQ VALLEY.
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION THIS EVENING
ACCOMPANIED BY A NARROW BAND OF HEAVY SHRA /AND POSSIBLY EVEN A
RUMBLE OF THUNDER/ FOLLOWED BY WESTERLY WINDS GUSTING BETWEEN 30 AND
35KTS ACROSS MOST OF THE REGION TONIGHT AND EARLY WEDNESDAY. GUSTS
COULD BE BETWEEN 45-50 MPH ACROSS THE NW MTNS AND LAUREL HIGHLANDS.
OUTLOOK...
WED...WESTERLY WINDS - GUSTING TO 35-40KT EARLY ACROSS THE WRN MTNS.
LAKE EFFECT SNOW SHOWERS NEAR..AND TO THE WEST OF KBFD WITH OCNL IFR
CIGS AND VSBYS MAINLY IN THE MORNING. NO SIG WX EXPECTED ELSEWHERE.
THU...SHSN OR EVEN A PERIOD OF STEADY LIGHT SNOW/REDUCED VSBYS
POSS...MAINLY W MTNS.
FRI...NO SIG WX EXPECTED.
SAT...PERIODS OF LGT SNOW NW AND MIXED PRECIP SE.
SUN...NO SIGNIF WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR
PAZ004>006-010-011.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 4 PM EST WEDNESDAY FOR
PAZ004.
WIND ADVISORY UNTIL 6 AM EST WEDNESDAY FOR PAZ017-024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...CERU/STEINBUGL
LONG TERM...CERU
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
315 PM EST TUE JAN 17 2012
.SYNOPSIS...
LOW PRESSURE OVER SOUTHERN LAKE HURON THIS AFTERNOON WILL STRENGTHEN
AS IT LIFTS NORTHEAST ACROSS THE LOWER GREAT LAKES AND DOWN
THE SAINT LAWRENCE RIVER VALLEY LATE TODAY AND TONIGHT. A SHARP COLD
FRONT TRAILING SOUTH FROM THIS LOW WILL SWEEP ACROSS THE
COMMONWEALTH EARLY TONIGHT...FOLLOWED BY A SURGE OF COLDER AIR AND
STRONG GUSTY WINDS. HIGH PRESSURE WILL MOVE INTO THE REGION LATER
WEDNESDAY INTO EARLY THURSDAY. A PAIR OF UPPER AIR DISTURBANCES AND
WEAK SURFACE LOWS SHOULD BRING A FEW PERIODS OF MAINLY LIGHT SNOW TO
THE REGION THURSDAY AFTERNOON AND NIGHT...AND AGAIN LATE FRIDAY
NIGHT INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
EXTREMELY STRONG 60-70KT 925-850 SWRLY LLJ WAS LIFTING NE ACROSS WRN
PENN AHEAD OF A DEEPENING AREA OF LOW PRESSURE CURRENTLY SITUATED
ACROSS THE SOUTHERN TIP OF LAKE HURON.
MOVED UP THE WIND ADVISORY BY 5 HOURS TO ACCOUNT FOR THIS STRONG
WIND IMPACT TO THE RIDGE TOPS OF THE LAURELS THIS AFTERNOON...AND
MAINTAINED THE PREVIOUS WIND ADVISORY FOR THE REST OF THE WESTERN
MTNS THIS EVENING INTO EARLY WEDNESDAY MORNING IN THE WAKE OF A
STRONG COLD FRONT.
FAST MOVING SHOWERS OF RAIN /ENE AT 60 KTS/ AND EVEN A FEW BREAKS IN
THE LAYERED CLOUD DECK WILL OCCUR IN THE STRONG/DEEP WSWRLY FLOW
AHEAD OF THE SFC COLD FRONT. THIS FRONT EXTENDED FROM JUST EAST OF
TOLEDO OHIO...TO WILMINGTON OHIO AT 1930Z AND WAS MOVING QUICKLY TO
THE EAST AT 40KT.
LINEAR EXTRAPOLATION BRINGS THE FRONT INTO WARREN COUNTY BETWEEN
23-00Z...AND AROUND 01Z ALONG THE LENGTH OF ROUTE 219 IN WRN PENN.
THE CFRONT WITH A LIKELY BAND OF GUSTY MDT TO BRIEFLY HEAVY RAIN
SHOWERS WILL REACH THE LOWER SUSQ VALLEY AROUND 03-04Z.
ELEVATED...925-850 MB LIFTED INDICES VIA THE RUC DROP TO NEAR...OR
SLIGHTLY BELOW ZERO ACROSS FAR SCENT PENN AND LOWER SUSQ VALLEY LATE
TODAY AND THIS EVENING. THIS MARGINAL INSTABILITY COULD SUPPORT A
FEW RUMBLES OF THUNDER ALONG THE COLD FRONTAL BOUNDARY.
VERY MILD TEMPS IN THE 40S...TO LOWER AND MID 50S IN THE SOUTH WILL
PLUMMET IN THE WAKE OF THE FRONT. THE MUCH COLDER TEMPS IN THE TEENS
/NW/...AND 20S SE WED MORNING WILL COMBINE WITH THE STRONG WESTERLY
WINDS TO BRING WIND CHILLS IN THE SINGLE DIGITS /NW/ TO TEENS /SE/.
ADDITIONAL RAINFALL LATE THIS AFTERNOON AND TONIGHT WILL AVERAGE
0.10-0.25 OF AN INCH.
RAIN SHOWERS WILL MIX WITH THEN CHANGE TO FREQUENT SHSN ACROSS THE
NW MTNS LATE THIS EVENING...WITH ACCUMULATING LES BANDS PUSHING
GRADUALLY INLAND FROM THE ERIE LAKE SHORE BY SHORTLY AFTER
MIDNIGHT.
THE BASE OF THE SUBSIDENCE INVERSION RISES TO 7-8 KFT AGL LATE
TONIGHT AND EARLY WEDNESDAY...AND A DECENT CROSS-HAIR SIGNATURE OF
UVVEL WITH THE PRIME THERMAL RIBBON FOR DENDRITIC GROWTH OCCURS
BETWEEN ABOUT 09Z AND 15Z WED...AND THAT/S WHEN THE MOST PERSISTENT
LES IS EXPECTED. RECENTLY ISSUED A LES ADVISORY FOR WARREN CTY
/MAINLY THE NW 1/3 OF THE CTY/ FROM 1 AM WED TO 4 PM WED FOR A
GENERAL 3-5 INCHES OF WIND WHIPPED SNOW AND OCNL VERY POOR VSBYS
VARIABLE AMOUNTS OF CLOUDS AND WINDY CONDITIONS WITH JUST SOME
FLURRIES WILL AFFECT THE CENTRAL RIDGE AND VALLEY REGION DURING THE
DAY WED. TEMP CURVE WILL BE VERY FLAT WEDNESDAY UNDER STRONG LLVL
COLD ADVECTION. MAX TEMPS AROUND 20F IN THE NW...AND LOWER TO MID
30S IN THE SE WILL BE JUST NEAR...TO A FEW DEG F BELOW NORMAL.
WINDS WILL RELAX BY WED AFTN AS HIGH PRES BUILDS TAKES UP BRIEF
RESIDENCE OVR PA. ANY LINGERING LAKE EFFECT OR UPSLOPE SNOW SHOWERS
SHOULD ALSO TAPER OFF THROUGHOUT THE AFTN.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
THE N-S RIDGE AXIS WILL PROVIDE A PD OF MAINLY DRY AND TRANQUIL
CONDS THRU WED NGT BEFORE THE NEXT SYS APPROACHES BY EARLY THURS.
HIGHS WILL AVG A FEW TO SEVERAL DEGS BELOW NORMAL WITH SEASONABLY
COLD OVERNIGHT READINGS IN THE TEENS AND 20S. SOME OF THE USUALLY
COLD RURAL VLYS IN THE NRN TIER COULD TOUCH THE SINGLE DIGITS UNDER
IDEAL RADIATIONAL COOLING.
A CLIPPER TYPE LOW WILL DROP THRU THE GRT LKS ON THURS. MDLS SHOW
A BAND OF LGT SNOW DEVELOPING IN THE PRE-FRONTAL WARM ADVN PTRN.
THE STEADY MVMT OF THIS SYS SHOULD LIMIT AMTS TO BLW ADVY
CRITERIA. A REINFORCING SHOT OF COLD AIR WILL ARRIVE BEHIND THIS
SYS FOR THURS NGT INTO FRI. HIGH PRES BRIEFLY RETURNS TO THE AREA
BY THE END OF THE PD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
COLD AIR WITH PERIODS OF LAKE EFFECT SNOW WILL CONTINUE THROUGH
FRIDAY. TEMPERATURES WILL BE COLD THROUGH FRIDAY...ESPECIALLY AS A
FINGER OF THE JET PROTRUDES THROUGH THE EASTERN GREAT LAKES ON
FRIDAY. WITH WARM AIR ADVECTION NEXT WEEKEND SHOULD SEE WARMER
TEMPERATURES SATURDAY AND SUNDAY. THOUGH THE CURRENT LONG RANGE
MODELS HAVE A WEAK TROUGH PROPAGATING THROUGH...WITH THE EC SHOWING
SLIGHTLY MORE AMPLITUDE...A GREATER NEGATIVE TILT AND SLOWER
PROGRESSION. GFS MOVES THE SYSTEM THROUGH EARLY SATURDAY. THE EC
BRINGING THE SYSTEM THROUGH LATE SATURDAY...EARLY SUNDAY. HOWEVER
THE DICHOTOMY OF THE MODELS REMAINS THAT BY MID SUNDAY THEY ARE
ALMOST 180 DEGREES OUT OF EACH OTHER. BASED ON THE CONSENSUS AND
RECENT TRENDS...HAVE BEST PRECIP CHANCES BY MIDDAY SATURDAY...WITH A
POSSIBILITY OF A RAIN SNOW MIX. HAVE BROUGHT UP PRECIP CHANCES ON
SUNDAY SLIGHTLY BUT MAINLY IN THE HIGHER ELEVATIONS. MAINLY DRY
CONDITIONS ELSEWHERE.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
AN APPROACHING LOW PRESSURE SYSTEM WILL BRING STRONG SWRLY FLOW
ALOFT...RESULTING IN CONTINUE LLWS ACROSS MOST OF CENTRAL PA THRU
THIS EVENING.
A FEW ADDITIONAL PERIODS OF RAIN SHOWERS ACCOMPANIED BY WIDESPREAD
MVFR CIGS AND MAINLY VFR VSBYS WILL OCCUR FOR THE REST OF TODAY.
AS LOW PRES CENTER TRACKS WEST OF THE STATE. LIFTING CIGS/IMPROVING
VSBYS WILL BE LIKELY ACROSS SOUTHERN PA LATE THIS AFTN/EVENING...
AS A WARM FRONT LIFTS NORTH OF THE MIDDLE SUSQ VALLEY.
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION THIS EVENING
ACCOMPANIED BY A NARROW BAND OF HEAVY SHRA /AND POSSIBLY EVEN A
RUMBLE OF THUNDER/ FOLLOWED BY WESTERLY WINDS GUSTING BETWEEN 30 AND
35KTS ACROSS MOST OF THE REGION TONIGHT AND EARLY WEDNESDAY. GUSTS
COULD BE BETWEEN 45-50 MPH ACROSS THE NW MTNS AND LAUREL HIGHLANDS.
OUTLOOK...
WED...WESTERLY WINDS - GUSTING TO 35-40KT EARLY ACROSS THE WRN MTNS.
LAKE EFFECT SNOW SHOWERS NEAR..AND TO THE WEST OF KBFD WITH OCNL IFR
CIGS AND VSBYS MAINLY IN THE MORNING. NO SIG WX EXPECTED ELSEWHERE.
THU...SHSN OR EVEN A PERIOD OF STEADY LIGHT SNOW/REDUCED VSBYS
POSS...MAINLY W MTNS.
FRI...NO SIG WX EXPECTED.
SAT...PERIODS OF LGT SNOW NW AND MIXED PRECIP SE.
SUN...NO SIGNIF WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR
PAZ004>006-010-011.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 4 PM EST WEDNESDAY FOR
PAZ004.
WIND ADVISORY UNTIL 6 AM EST WEDNESDAY FOR PAZ017-024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...CERU/STEINBUGL
LONG TERM...CERU
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
337 PM CST TUE JAN 17 2012
.SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...A COLD FRONT IS
CURRENTLY DRAPED FROM NORTH OF VICTORIA TO NEAR LAREDO. THE FRONT
WILL PUSH THROUGH THE REST OF THE AREA LATE THIS
AFTERNOON...PUSHING OFFSHORE BY EVENING. WITH A CAP REMAINING OVER
THE AREA DONT EXPECT TO SEE SHOWERS OVER LAND...BUT MAY BE ABLE TO
DEVELOP A FEW OFFSHORE THIS EVENING. RUC GUIDANCE HAS SEEMED
PRETTY REASONABLE WITH FRONTAL TIMING AND WINDS SO LARGELY GOING
WITH THAT FOR WINDS THIS EVENING...EXPECTING A BRIEF INCREASE OVER
LAND AREAS AND THEN AN INCREASE TO 20 TO 25 KNOTS OVER THE WATER.
A SMALL CRAFT ADVISORY IS IN EFFECT FROM 8PM THIS EVENING THROUGH
9AM TOMORROW. BEHIND THE FRONT HIGH PRESSURE WILL QUICKLY BUILD IN
AND LEAD TO LIGHT WINDS TOMORROW ACROSS THE AREA. BY WEDNESDAY
NIGHT WINDS ARE ALREADY SHIFTING TO THE SOUTHEAST. AN AREA OF MID
AND HIGH LEVEL CLOUDS PUSHING IN FROM THE WEST SHOULD KEEP TEMPS
MAINLY IN THE 40S THIS EVENING...WITH SOME UPPER 30S IN THE FAR
NORTHEAST. AFTER NEAR RECORD HIGHS TODAY...MAX TEMPS WILL BE IN
THE 60S AREA WIDE TOMORROW. SOUTHERLY WINDS KEEP TEMPS UP
WEDNESDAY NIGHT.
&&
.LONG TERM (THURSDAY THROUGH TUESDAY)...THURSDAY THROUGH SATURDAY
WILL FEATURE A MAINLY ZONAL FLOW ALOFT WITH A WARMING TREND ACROSS
SOUTH TEXAS...AND ABOVE NORMAL HIGHS. A GRADUAL MOISTENING OF THE
LOWER LEVELS WILL ALSO TAKE PLACE...WITH PERIODS OF OVERNIGHT AND
MORNING FOG/SEA FOG TO CONTEND WITH FRI/SAT. A WEAK FRONTAL BOUNDARY
WILL STALL OVER THE NORTHERN CWA SATURDAY MORNING AND WASH OUT. NEXT
CHANCE OF PRECIP WILL COME LATE SUNDAY INTO MONDAY MORNING AS A
SOUTHERN STREAM SHORTWAVE APPROACHES FROM BAJA CALIFORNIA. WILL KEEP
POPS IN THE 20% RANGE FOR NOW AS THERE HAVE BEEN SOME MODEL
CONSISTENCY ISSUES WITH TIMING/STRENGTH OF DISTURBANCE. THE
DISTURBANCE BECOMES ABSORBED INTO LARGER TROUGH TO THE NORTHWEST ON
MONDAY...WHICH EVENTUALLY PUSHES A COLD FRONT INTO THE AREA TUESDAY.
AGAIN...TIMING AND STRENGTH DIFFERENCES WITH RESPECT TO UPPER LEVEL
TROUGH AND CORRESPONDING COLD FRONT BETWEEN ECMWF/GFS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 45 63 48 79 58 / 10 0 0 0 0
VICTORIA 38 61 46 75 57 / 10 0 0 0 0
LAREDO 47 64 52 78 58 / 0 0 0 0 0
ALICE 45 64 48 80 58 / 10 0 0 0 0
ROCKPORT 43 60 49 69 58 / 10 0 0 0 0
COTULLA 41 63 43 78 54 / 0 0 0 0 0
KINGSVILLE 46 64 48 80 58 / 10 0 0 0 0
NAVY CORPUS 47 61 51 73 60 / 10 0 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 9 AM CST
WEDNESDAY FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM
BAFFIN BAY TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT
ARANSAS TO PORT O`CONNOR...COASTAL WATERS FROM BAFFIN BAY
TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT
ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM
BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM
PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
PZ/83...SHORT TERM
JR/76...LONG TERM