Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/16/12
AREA FORECAST DISCUSSION
NWS ALBANY NY
1239 AM EST SAT JAN 14 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES
INTO THE CANADIAN MARITIMES OVERNIGHT. BLUSTERY AND COLD
CONDITIONS WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS
AND FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS
DAYBREAK. ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN
ONTARIO LATE SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT
FRIGID TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1235 AM EST...SNOW SHOWERS/FLURRIES HAVE INCREASED IN AREAL
COVERAGE ONCE AGAIN FROM THE CAPITAL REGION WEST AND NORTH...WITH
A BAND OF HEAVIER SNOW SHOWERS EVIDENT ON RADAR ACROSS SOUTH
CENTRAL HERKIMER CO INTO NORTHERN SARATOGA CO. THIS BAND HAS BEEN
MOVING SLOWLY SOUTHWARD...AND AS LOW LEVEL WINDS CONTINUE
VEERING...THIS BAND SHOULD ALSO CONTINUE MOVING SOUTH...AFFECTING
THE WESTERN MOHAWK VALLEY OVER THE NEXT 1-2 HOURS...AS WELL AS
AREAS FROM THE CAPITAL REGION N AND W. WITHIN THIS BAND...LOCALLY
HEAVY BURSTS OF SNOW WILL BE POSSIBLE. EXPECT AN ADDITIONAL 1-3
INCHES ACROSS PORTIONS OF SOUTHERN HERKIMER CO...WITH GENERALLY A
DUSTING TO UNDER AN INCH ELSEWHERE. HAVE INCREASED POPS FOR THESE
AREAS ACCORDINGLY BASED ON RADAR TRENDS.
ELSEWHERE...SNOW SHOWERS ARE PERSISTING ACROSS NORTHERN
HERKIMER/HAMILTON COS. ALTHOUGH INTENSITY HAS DECREASED...STILL
CAN EXPECT UP TO AN ADDITIONAL INCH OR TWO OF ACCUM THROUGH
DAYBREAK. WILL KEEP CURRENT SUITE OF ADVISORIES FOR THIS REGION.
HAVE BOOSTED TEMPS UPWARD...AND SLOWED THE TEMP CURVE OVER THE
NEXT 3 HOURS...AS PERSISTENT CLOUDS...AND SOME LOW LEVEL WARMTH/MOISTURE
FROM THE LAKES KEEP TEMPS FROM FALLING MUCH...GENERALLY HOLDING IN
THE 25-30 RANGE. THEN...TOWARD DAYBREAK...A QUICKER DROP OFF IN
TEMPS IS EXPECTED AS THE ARCTIC COLD FRONT DRIFTS SE. ACTUAL MIN
TEMPS MAY NOT OCCUR UNTIL AROUND OR JUST AFTER DAYBREAK.
PREVIOUS DISCUSSIONS FOLLOW...
WINTER STORM WARNING AND SOME OF THE WINTER WEATHER ADVISORIES
HAVE BEEN DROPPED.
SNOW HAS DIMINISHED GREATLY ACROSS THE REGION AS THE INVERSIONS
AND MOISTURE LAYER HAVE BECOME MORE SHALLOW. LAKE EFFECT BAND
NOSING INTO HERKIMER AND HAMILTON COUNTIES RELATIVELY STABLE AND
SHOULD CONTINUE TO PRODUCE LIGHT TO MODERATE SNOW...LOCALLY HEAVY
SNOW THROUGH THE EARLY MORNING HOURS. HAVE DROPPED ALL HEADLINES
EXCEPT FOR THE WINTER WEATHER ADVISORY IN THE WESTERN MOHAWK
VALLEY AND SOUTHERN ADIRONDACKS...WHERE IT HAS BEEN EXTENDED UNTIL
6 AM. THE LAKE EFFCT BAND MAY BREAK UP BEFORE THEN BUT IT CAN BE
CANCELLED EARLY IF NECESSARY. THERE MAY BE ONLY AN INCH OR TWO
ADDITIONAL ACCUMULATION IN THOSE AREAS...WITH STORM TOTALS OF 4
TO UP TO AROUND 8 INCHES LOCALLY.
WITH THE CLOUD COVER AND THE WINDS STAYING UP...TEMPERATURES ARE
NOT FALLING MUCH...BUT UPSTREAM TEMPERATURES SHOULD ADVECT INTO
OUR REGION BY DAYBREAK. SO...LOW TEMPERATURES SEEM TO BE IN THE
BALLPARK.
PREV AFD BELOW...
WIND ADVISORY CANCELLED AS WINDS HAVE DIMINISHED.
SOME OF THE SNOW IN THE WESTERN MOHAWK VALLEY...SOUTHERN
ADIRONDACKS...SCHOHARIE VALLEY AND CATSKILLS HAS DIMINISHED. AS
THE MEAN FLOW TURNS MORE WEST AND WEST NORTHWEST...SOME LAKE
EFFECT SNOW COULD NOSE BACK INTO THE WESTERN MOHAWK VALLEY AND
SOUTHERN ADIRONDACKS. SO...WINTER WEATHER ADVISORY WILL CONTINUE
FOR THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...BUT SNOW
CHANCES WILL BE REDUCED IN THE SCHOHARIE VALLEY AND CATSKILLS.
SNOW STILL AFFECTING THE SOUHTERN BERKSHIRES AND SOUTHERN VT SO
WINTER STORM WARNINGS WILL CONTINUE THERE. TEMPERATURES HAVE
FALLEN A BIT MORE RAPIDLY THAN WHAT WAS FORECASTED FOR THE CURRENT
TIME...BUT OVERALL LOW TEMPERATURES FOR LATER TONIGHT SHOULD BE IN
THE BALL PARK. 00Z DATA AND RADAR TRENDS WILL BE CHECKED FOR MORE
CHANGES LATER THIS EVENING.
PREV AFD BELOW...
AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF
SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG
THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST
RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY
AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN
BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER
STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE
UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR
RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS
OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE
INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA
COUNTIES TO 4-8" TOO.
PREVIOUS NEAR TERM...
AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE
POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN
IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW
ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC
LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED
OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE
OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES.
THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW
HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK
VALLEY.
THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL
BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A
REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF
THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A
CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY
ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID
LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE
UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR
WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND
HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z-
03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST
NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS.
THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN
HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL
CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC
ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED
THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK
VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS
EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE
CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY
TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER
CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE.
LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE
INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH
THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE
TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF
ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE
A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW
SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE
WILL HAVE TO MONITOR IF THIS MATERIALIZES.
IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35
KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM
KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO
35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE
CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE
LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC
TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP
THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE
SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS
AROUND 35 MPH.
A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION
BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF
SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH.
LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE
ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM
KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN
MTNS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS
THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST.
THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING
CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND
FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG
SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY
FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF
THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN
CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES
OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX
TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE
SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S
NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE
DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY
WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO
NORTH AND WEST OF THE CAPITAL REGION.
SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH
THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY
LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN
EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION
IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS
IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND
EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN
THE SRN DACKS.
SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW
ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL
WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT
SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE
START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS
DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF
A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS
WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK
VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS
NORTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE
ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE
IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE
TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST
INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST
TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW
WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS
AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY.
THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A
NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH
CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE
MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE
LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT
THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE
OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING
THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH
WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A
WINTRY MIX...DEPENDING ON ELEVATION.
THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE
NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE
SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED
BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY
INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH
DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE
UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO
CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS.
NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD
OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE
FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
MONITORING A BAND OF LAKE EFFECT SNOW THAT CONTINUES TO MIGRATE
SOUTH ACROSS THE MOHAWK VALLEY. LATEST RUC13/HRRR DOES SUGGEST THIS
BAND WILL HAVE AN IMPACT ON KALB AND WE WILL PLACE A TEMPO GROUP FOR
MVFR CONDITIONS UP TO 09Z. OTHERWISE...HIGH END MVFR OR VFR
CONDITIONS ARE EXPECTED THIS TAF FORECAST CYCLE.
WINDS WILL REMAIN ELEVATED THANKS TO A TIGHT PRESSURE GRADIENT AND
INCREASING MIXING POTENTIAL WITH SUNRISE. WIND GUSTS COULD EXCEED
20KTS WITH A GENERAL WEST-NORTHWEST WIND DIRECTION. WINDS WILL
BECOME NORTHWEST IN THE WAKE OF THE LAST FRONTAL BOUNDARY FROM THIS
AFTERNOON INTO SATURDAY EVENING.
OUTLOOK...
SAT OVRNT-MON...VFR...NO SIG WX.
MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX.
WED...VFR...SLGT CHC --SHSN.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE
NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO
THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER
THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL
BY TUESDAY.
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...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ032-033-038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/NAS/WASULA
NEAR TERM...KL/NAS/WASULA
SHORT TERM...WASULA
LONG TERM...KGM/LFM
AVIATION...BGM
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
630 AM EST SAT JAN 14 2012
.SYNOPSIS...
A COLD FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA TODAY AND
TONIGHT. COLD HIGH PRESSURE FROM THE WEST IS EXPECTED TO
INFLUENCE OUR WEATHER FOR SUNDAY AND SUNDAY NIGHT BEFORE PASSING
OUT TO SEA ON MONDAY. A WARM FRONT FROM THE WEST AND SOUTHWEST IS
ANTICIPATED TO WORK ITS WAY THROUGH OUR REGION ON TUESDAY,
FOLLOWED BY A COLD FRONT ON TUESDAY NIGHT. AN AREA OF HIGH
PRESSURE IS EXPECTED FOR WEDNESDAY AND THURSDAY. A WEAK FRONTAL
BOUNDARY FROM THE NORTHWEST MAY ARRIVE ON THURSDAY NIGHT OR
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 10Z SURFACE ANALYSIS PLACED A COLD FRONT FROM NEW ENGLAND TO
THE UPPER OHIO VALLEY. HIGH PRESSURE WAS OVER THE UPPER GREAT
LAKES WITH ANOTHER HIGH ALONG THE GULF COAST. LOW PRESSURE WAS
JUST NORTH OF THE DAKOTAS ALONG A FRONTAL BOUNDARY TO ANOTHER LOW
IN THE CENTRAL PLAINS. AN UPPER AIR ANALYSIS PLACED A DEEP TROUGH
ACROSS THE EASTERN STATES WITH SEVERAL SHORT WAVES EMBEDDED WITHIN
THE FLOW. AN AREA OF FOCUSED WAA AT 850 MB WAS ACROSS THE CENTRAL
PLAINS. A CYCLONICALLY CURVED 300 MB JET WAS FROM THE NORTHERN
ROCKIES TO THE LOWER MISSISSIPPI VALLEY THEN UP THE EAST COAST.
A STRONG SURFACE LOW WILL REMAIN IN THE CANADIAN MARITIMES TODAY.
THIS WILL RESULT IN A CONTINUED CYCLONIC FLOW OF COLD AIR ACROSS
THE ENTIRE REGION. A SECONDARY COLD FRONT WILL WRAP AROUND THIS
SURFACE LOW AND WILL BE SETTLING SOUTHWARD ACROSS OUR AREA. THE
OVERALL LOW-LEVEL MOISTURE IS LACKING WITH THIS BOUNDARY, HOWEVER
THERE IS A RIBBON OF DECENT LIFT, CONVERGENCE AND STEEPENING LOW-
LEVEL LAPSE RATES. GIVEN THE WESTERLY FLOW OF COLD AIR, SOME ADDED
MOISTURE FROM LAKE ERIE MAY COME INTO PLAY THROUGH THE DAY. SOME
OF THE HIGHER RESOLUTION MODELS LIKE THE NAM/WRF, THE SPC 4KM WRF
AND THE HRRR HINT AT A CONNECTION BETWEEN A LAKE ERIE PLUME AND
THE COLD FRONT. ALOFT, AN AREA OF CHANNELIZED VORTICITY IS
FORECAST TO PIVOT NEARLY CLOSE TO THE SURFACE FRONT. THIS MAY HELP
TO PULL THE LAKE SNOW PLUME EASTWARD IN THE FORM OF A NARROW BAND.
THE FORECAST SOUNDINGS ACROSS THE NORTHWESTERN ZONES SHOW THE
INVERSION STAYING HIGH ENOUGH TO ALLOW THE SYNOPTIC LIFT TO OCCUR
WITHIN THE FAVORABLE SNOW GROWTH REGION. IF A BAND OF SNOW DOES
DEVELOP, A QUICK BURST MAY RESULT. THE ABOVE MENTIONED MODELS, AND
TO SOME EXTENT THE GFS, BRING THIS ALL THE WAY TO THE POCONOS TO
EVEN PORTIONS OF NORTHERN NEW JERSEY. OUR CONFIDENCE IS LOW
REGARDING HOW THIS MAY PLAY OUT, BUT THERE IS THE POTENTIAL FOR A
NARROW BAND OF HEAVIER SNOW SHOWERS MOVING THROUGH PARTS OF THE
NORTHWESTERN ZONES. THIS THEN SETTLES SOUTHWARD WITH THE FRONT BUT
WEAKENS AS THE MAIN SUPPORT TRACKS FARTHER NORTH. SOME WEAK SHORT
WAVE ENERGY IS HELPING TO PRODUCE SOME FLURRIES OR A FEW SNOW
SHOWERS ACROSS MAINLY THE POCONOS EARLY THIS MORNING. SOME SLIGHT
CHC POPS WERE USED EARLY THIS MORNING, THEN WE LEANED TOWARD THE
NAM/WRF FOR POPS WHICH PLACES POPS IN THE SLIGHT CHC TO CHC RANGE
MAINLY ACROSS NORTHEASTERN PENNSYLVANIA. WE KEPT ABOUT ONE-HALF
INCH OF SNOW ACCUMULATION ACROSS THE POCONOS.
ELSEWHERE, LITTLE TO NOTHING IS EXPECTED WITH THE FRONTAL PASSAGE
OTHER THAN A BAND OF STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS.
THE TAIL END OF A WEAK SHORT WAVE IS HELPING TO GENERATE A SWATH
OF MAINLY MID LEVEL CLOUDS ACROSS THE SOUTHEASTERN ZONES EARLY
THIS MORNING. SOME RETURNS HAVE BEEN SHOWING UP ON RADAR ACROSS
NORTHEASTERN MARYLAND TO SOUTHWESTERN NEW JERSEY. PERHAPS A FEW
FLURRIES REACH THE GROUND, BUT OVERALL THIS LOOKS TO BE MID LEVEL
MOISTURE ONLY. BACK TO THE STRATOCUMULUS, THIS WILL BE AROUND
TODAY ESPECIALLY ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW
JERSEY AS THE WESTERLY FLOW MAINTAINS ENOUGH MOISTURE UNDER AN
INVERSION. THE FORECAST SOUNDINGS INDICATE WE SHOULD GET RATHER
CLOSE TO THE CONVECTIVE TEMPERATURES TODAY DESPITE THE LOWER
LEVELS BEING RATHER DRY. THIS SHOULD RESULT IN AT LEAST SOME
STRATOCUMULUS BELOW SOME HIGHER CLOUDS ACROSS THE REST OF THE CWA,
WHICH MAY RESULT IN VARYING CLOUD COVER THROUGH THE DAY. BASED ON
SATELLITE TRENDS AS OF 11Z, WE INCREASED THE SKY COVER FARTHER
EAST FOR AWHILE THIS MORNING.
A WESTERLY WIND WILL CONTINUE TO BE ON THE BRISK SIDE AS VERTICAL
MIXING IS MAINTAINED. THE WINDS HOWEVER ARE EXPECTED TO BE LESS
THAN WHAT WAS OBSERVED YESTERDAY, AND SETTLE DOWN LATER IN THE
AFTERNOON. AS FOR TEMPERATURES, WE MAINLY TOOK AN EVENLY WEIGHTED
BLEND OF THE MOS GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE AFOREMENTIONED SECONDARY COLD FRONT WILL CONTINUE TO SETTLE
SOUTHWARD BEFORE POTENTIALLY DISSIPATING. THERE COULD BE SOME
LINGERING FLURRIES OR A SNOW SHOWER WITH IT ESPECIALLY IN THE
WESTERN ZONES. HOWEVER, ANYTHING WITH IT SHOULD BE WANING WITH A
SOUTHERN EXTENT AS THE OVERALL LIFT AND MOISTURE DWINDLES AS WELL
AS A GRADUAL INCREASE IN THE SUBSIDENCE AND A LESS FAVORABLE FETCH
FROM THE LAKES. THEREFORE, KEPT THE SKY COVER A BIT HIGHER FOR A
TIME WITHIN A WEST TO EAST BAND WITH THE SOUTHBOUND FRONT. THERE
MAY BE ENOUGH MID LEVEL MOISTURE AROUND TO KEEP SOME CLOUDS
AROUND, BUT OVERALL AN EVEN DRIER PUSH OF AIR FROM THE NORTH
SHOULD RESULT IN SOME SCATTERING IN THE CLOUDS ESPECIALLY SOUTH
AND EAST OF THE PHILADELPHIA METRO AREA.
AS STRENGTHENING HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN CANADA
AND THE EASTERN GREAT LAKES LATE TONIGHT, THE NORTHERLY FLOW WILL
DRIVE A COLDER AIR MASS OVER OUR AREA. THE 850 MB TEMPERATURES ARE
FORECAST TO DROP TO NEAR -15C OVERNIGHT. THERE IS SOMEWHAT OF A
PRESSURE GRADIENT REMAINING DURING THE NIGHT, HOWEVER THE OVERALL
MIXING SHOULD TEND TO BECOME MUCH MORE REDUCED AS THE NIGHT WEARS
ON. THIS WILL RESULT IN A RATHER COLD NIGHT ACROSS THE ENTIRE
AREA.
AS FOR TEMPERATURES, WE GENERALLY WENT WITH A BLEND OF THE
GFS/NAM MOS WITH SOME TWEAKS MAINLY FOR THE TYPICALLY COLDER
LOCALES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MOSTLY CLEAR AND COLD WEATHER IS ANTICIPATED FOR SUNDAY AND
SUNDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS OUR REGION. MAXIMUM
TEMPERATURES SHOULD RANGE FROM THE UPPER TEENS IN THE POCONOS TO
THE MIDDLE 30S IN SOUTHERN DELAWARE. FOR SUNDAY NIGHT, READINGS
ARE FORECAST TO DROP INTO THE TEENS THROUGHOUT MOST OF OUR REGION
WITH A LIGHT WIND AND GOOD RADIATIVE CONDITIONS.
THE MID LEVEL RIDGE AXIS IS FORECAST TO PASS OVERHEAD ON MONDAY
MORNING WITH STRONG WARM ADVECTION DEVELOPING ALOFT. FROM MONDAY
INTO MONDAY EVENING WE SHOULD SEE AN INCREASE IN HIGH, THEN MID
LEVEL CLOUDS.
ON MONDAY NIGHT, A DEVELOPING JET AROUND 850 HPA WILL BE LOCATED
OVER THE OHIO RIVER VALLEY, AHEAD OF OUR NEXT WEATHER SYSTEM
APPROACHING FROM THE WEST. THE JET SHOULD DROP SLOWLY
SOUTHEASTWARD, POINTING SQUARELY AT OUR FORECAST AREA. IT WILL ACT
TO DIRECT MOISTURE INTO OUR REGION RATHER QUICKLY. MONDAY NIGHT
SHOULD START DRY. HOWEVER, PRECIPITATION IS EXPECTED TO OVERSPREAD
OUR REGION. WITH COLD DRY AIR IN PLACE AT THE LOW LEVELS, WE MAY
VERY WELL ENCOUNTER PRECIPITATION TYPE ISSUES, MAINLY IN EASTERN
PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY. BASED ON THEN
EXPECTED TEMPERATURE PROFILES AND THE ANTICIPATION THAT STRONG
WARM ADVECTION ALOFT WILL CONTINUE, IT APPEARS AS THOUGH WE MAY
SEE A MIX OF MAINLY SLEET AND FREEZING RAIN IN OUR NORTHWESTERN
COUNTIES. A LITTLE SNOW IS ALSO POSSIBLE. HOWEVER, THAT WILL
DEPEND UPON A SOMEWHAT WEAKER INITIAL PUSH OF WARM AIR ALOFT THAN
MOST OF THE GUIDANCE IS CURRENTLY SUGGESTING. ON THE COASTAL
PLAIN, IT LOOKS AS THOUGH TEMPERATURES AT THE SURFACE AND ALOFT
WILL SUPPORT ALL RAIN ON MONDAY NIGHT.
AS THE WARM ADVECTION CONTINUES ON TUESDAY. THE WINTRY
PRECIPITATION SHOULD CHANGE TO ALL RAIN. THE RAIN MAY BECOME
SHOWERY DURING THE AFTERNOON. WE ARE NOT PARTICULARLY CONFIDENT IN
THE TEMPERATURE FORECAST FOR TUESDAY. THE LOW LEVEL COLD AIR MAY
BE A LITTLE MORE STUBBORN UP NORTH THAN OUR FORECAST INDICATES.
ALSO, IN OUR FAR SOUTHERN COUNTIES, SIGNIFICANT BREAKS IN THE
CLOUD COVER COULD RESULT IN TEMPERATURES HIGHER THAN THOSE WE ARE
FORECASTING.
A COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE ON TUESDAY NIGHT
WITH HIGH PRESSURE AND DRY WEATHER FOLLOWING FOR WEDNESDAY AND
THURSDAY. THE SOURCE REGION FOR THE AIR MASS WILL BE MORE FROM THE
WEST THAN THE NORTHWEST, SO TEMPERATURES WILL LIKELY BE ABOUT
NORMAL FOR THIS TIME OF THE YEAR.
A WEAK FRONTAL BOUNDARY MAY DROP INTO OUR REGION FROM THE
NORTHWEST LATE IN THE WEEK. FOR NOW, WE HAVE SIMPLY INDICATE A
SLIGHT CHANCE OF SNOW SHOWERS WITH THE FEATURE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A STRONG LOW PRESSURE SYSTEM IN THE CANADIAN MARITIMES THROUGH
TONIGHT WILL MAINTAIN A WEST TO NORTHWEST FLOW ACROSS OUR AREA. A
SECONDARY FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA FROM LATER
THIS MORNING THROUGH THE EVENING. THERE IS NOT MUCH FORCING AND
MOISTURE WITH THIS BOUNDARY, HOWEVER THERE ARE SOME HINTS IN THE
MODEL GUIDANCE THAT MOISTURE FROM THE EASTERN GREAT LAKES GETS
PULLED EASTWARD WITH THIS FRONT. THIS MAY RESULT IN ENOUGH LOW-
LEVEL CONVERGENCE TO ALLOW FOR A NARROW BAND OF FLURRIES OR
HEAVIER SNOW SHOWERS ACROSS THE NORTHERN PORTION OF PENNSYLVANIA
INTO NORTHWESTERN NEW JERSEY. AS A RESULT, A FEW SNOW SHOWERS MAY
GET TO AT LEAST KABE. GIVEN THE LOWER CONFIDENCE WITH THE TIMING
AND EXTENT OF ANY SNOW SHOWERS, WE DID NOT CARRY A MENTION IN THE
TAFS AT THIS TIME.
THE COLD WESTERLY FLOW COMBINED WITH SOME WEAK ENERGY MOVING
THROUGH AND ENOUGH MOISTURE TRAPPED UNDER AN INVERSION, IS HELPING
TO PULL STRATOCUMULUS DOWN ACROSS MOST OF THE AREA ALONG WITH MID
LEVEL CLOUDINESS. THIS IS EXPECTED TO CONTINUE WITH AT LEAST
BROKEN CEILINGS AROUND 4,000 FEET, ESPECIALLY FROM THE KPHL METRO
AREA ON NORTH AND WESTWARD. THE WINDS HAVE BEEN DECOUPLING SOME
WITH GUSTS DROPPING OFF AT SOME OF THE TERMINALS EARLY THIS
MORNING. ALL OF OUR TERMINALS ARE EXPECTED TO HAVE SOME GUSTS IN
THE 20-25 KNOT RANGE FOR AWHILE TODAY BEFORE SETTLING DOWN LATER
IN THE AFTERNOON AND TONIGHT. THE AFOREMENTIONED BOUNDARY SHOULD
MAINTAIN SOME STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS WITH IT
AS IT DROPS SOUTHWARD THROUGH THE EVENING. THIS BOUNDARY WILL ALSO
TURN THE SURFACE WINDS MORE TO THE NORTHWEST THROUGH TONIGHT.
OUTLOOK...
DRY WEATHER AND VFR CONDITIONS ARE FORECAST FOR SUNDAY AND
MONDAY. PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION FROM
THE WEST ON MONDAY NIGHT AND IT SHOULD CONTINUE INTO TUESDAY. THE
PRECIPITATION MAY BEGIN AS A WINTRY MIX ON MONDAY NIGHT AT KRDG,
KABE AND PERHAPS KTTN. ALL RAIN IS ANTICIPATED FOR KPHL, KPNE,
KILG, KMIV AND KACY.
A COLD FRONT IS EXPECTED TO PASS THROUGH OUR REGION ON TUESDAY
NIGHT, BRINGING AND END TO THE RAIN. HIGH PRESSURE AND DRY WEATHER
SHOULD FOLLOW FOR WEDNESDAY.
&&
.MARINE...
AN INTENSE SURFACE LOW OVER THE CANADIAN MARITIMES WILL CONTINUE
TO CIRCULATE A COLD AIR MASS OVER OUR REGION UNDER A WESTERLY FLOW.
A SECONDARY COLD FRONT WILL SWING AROUND THIS LOW AND SETTLE
SOUTHWARD ACROSS THE AREA TODAY INTO TONIGHT. SOME COLDER AIR WILL
ADVECT INTO THE AREA BEHIND THIS FRONT THROUGH TONIGHT. THE
PRESSURE GRADIENT REMAINS TIGHTENED TODAY INTO TONIGHT, HOWEVER
THE OVERALL WIND FIELD IS FORECAST TO LESSEN WITH TIME. THIS HAS
ALREADY BEEN NOTED AS THE WINDS HAVE BEEN GRADUALLY COMING DOWN
EARLY THIS MORNING. WHILE THERE COULD BE SOME UPTICK FOR A TIME
THIS MORNING DUE TO A LITTLE BETTER MIXING, IT MIGHT END UP BEING
A MORE MARGINAL SETUP FOR A SMALL CRAFT ADVISORY /ESPECIALLY
ACROSS THE SOUTHERN ZONES/. BASED ON THE SOUNDINGS AND TO ALLOW
FOR SOME WIGGLE ROOM, THE ADVISORY WILL RUN UNTIL 18Z FOR ALL
AREAS. THIS CAN ALWAYS BE CANCELLED EARLY. OTHERWISE, A DOWNWARD
TREND IN THE SEAS AND WINDS UNDER ADVISORY CRITERIA ARE EXPECTED
TONIGHT AS HIGH PRESSURE EDGES CLOSER.
WITH THE NORTHWEST FLOW PERSISTING INTO SUNDAY, WIND GUSTS TO
AROUND 25 KNOTS ARE POSSIBLE AT THAT TIME. HIGH PRESSURE SHOULD
BUILD ACROSS THE COASTAL WATERS OF NEW JERSEY AND DELAWARE ON
SUNDAY NIGHT AND EARLY MONDAY, BRINGING RELATIVELY TRANQUIL
CONDITIONS.
WIND SPEEDS ARE FORECAST TO BE ON THE INCREASE AGAIN LATE ON
MONDAY AS OUR NEXT WEATHER SYSTEM BEGINS TO APPROACH FROM THE
WEST. A BRISK SOUTHERLY FLOW IS ANTICIPATED FOR MONDAY NIGHT AND
TUESDAY WITH WIND GUSTS IN EXCESS OF 25 KNOTS, ALONG WITH WAVE
HEIGHTS ON OUR OCEAN WATERS BUILDING TO 5 TO 8 FEET.
A COLD FRONT IS EXPECTED TO PASS ACROSS THE REGION ON TUESDAY
NIGHT. THE WIND DIRECTION WILL LIKELY SHIFT TO THE WEST. HOWEVER,
GUSTS NEAR 25 KNOTS WILL REMAIN POSSIBLE INTO WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-
431-450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
356 AM EST SAT JAN 14 2012
.SYNOPSIS...
A COLD FRONT EXTENDED FROM NORTHERN NEW ENGLAND TO THE GREAT
LAKES EARLY THIS MORNING. THE BOUNDARY WILL PROGRESS TO THE SOUTH
AND IT SHOULD DROP INTO OUR REGION TONIGHT. COLD HIGH PRESSURE
FROM THE WEST IS EXPECTED TO INFLUENCE OUR WEATHER FOR SUNDAY AND
SUNDAY NIGHT BEFORE PASSING OUT TO SEA ON MONDAY. A WARM FRONT
FROM THE WEST AND SOUTHWEST IS ANTICIPATED TO WORK ITS WAY THROUGH
OUR REGION ON TUESDAY, FOLLOWED BY A COLD FRONT ON TUESDAY NIGHT.
AN AREA OF HIGH PRESSURE IS EXPECTED FOR WEDNESDAY AND THURSDAY. A
WEAK FRONTAL BOUNDARY FROM THE NORTHWEST MAY ARRIVE ON THURSDAY
NIGHT OR FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 07Z SURFACE ANALYSIS PLACED A COLD FRONT FROM NEW ENGLAND TO
THE NORTHERN OHIO VALLEY. HIGH PRESSURE WAS OVER THE UPPER GREAT
LAKES WITH ANOTHER HIGH ALONG THE GULF COAST. LOW PRESSURE WAS
JUST NORTH OF THE DAKOTAS ALONG A FRONTAL BOUNDARY TO ANOTHER LOW
IN THE CENTRAL PLAINS. AN UPPER AIR ANALYSIS PLACED A DEEP TROUGH
ACROSS THE EASTERN STATES WITH SEVERAL SHORT WAVES EMBEDDED WITHIN
THE FLOW. AN AREA OF FOCUSED WAA AT 850 MB WAS ACROSS THE CENTRAL
PLAINS. A CYCLONICALLY CURVED 300 MB JET WAS FROM THE NORTHERN
ROCKIES TO THE LOWER MISSISSIPPI VALLEY THEN UP THE EAST COAST.
A STRONG SURFACE LOW WILL REMAIN IN THE CANADIAN MARITIMES TODAY.
THIS WILL RESULT IN A CONTINUED CYCLONIC FLOW OF COLD AIR ACROSS
THE ENTIRE REGION. A SECONDARY COLD FRONT WILL WRAP AROUND THIS
SURFACE LOW AND WILL BE SETTLING SOUTHWARD ACROSS OUR AREA. THE
OVERALL LOW-LEVEL MOISTURE IS LACKING WITH THIS BOUNDARY, HOWEVER
THERE IS A RIBBON OF DECENT LIFT, CONVERGENCE AND STEEPENING LOW-
LEVEL LAPSE RATES. GIVEN THE WESTERLY FLOW OF COLD AIR, SOME ADDED
MOISTURE FROM LAKE ERIE MAY COME INTO PLAY THROUGH THE DAY. SOME
OF THE HIGHER RESOLUTION MODELS LIKE THE NAM/WRF, THE SPC 4KM WRF
AND THE HRRR HINT AT A CONNECTION BETWEEN A LAKE ERIE PLUME AND
THE COLD FRONT. ALOFT, AN AREA OF CHANNELIZED VORTICITY IS
FORECAST TO PIVOT NEARLY CLOSE TO THE SURFACE FRONT. THIS MAY HELP
TO PULL THE LAKE SNOW PLUME EASTWARD IN THE FORM OF A NARROW BAND.
THE FORECAST SOUNDINGS ACROSS THE NORTHWESTERN ZONES SHOW THE
INVERSION STAYING HIGH ENOUGH TO ALLOW THE SYNOPTIC LIFT TO OCCUR
WITHIN THE FAVORABLE SNOW GROWTH REGION. IF A BAND OF SNOW DOES
DEVELOP, A QUICK BURST MAY RESULT. THE ABOVE MENTIONED MODELS, AND
TO SOME EXTENT THE GFS, BRING THIS ALL THE WAY TO THE POCONOS TO
EVEN PORTIONS OF NORTHERN NEW JERSEY. OUR CONFIDENCE IS LOW
REGARDING HOW THIS MAY PLAY OUT, BUT THERE IS THE POTENTIAL FOR A
NARROW BAND OF HEAVIER SNOW SHOWERS MOVING THROUGH PARTS OF THE
NORTHWESTERN ZONES. THIS THEN SETTLES SOUTHWARD WITH THE FRONT BUT
WEAKENS AS THE MAIN SUPPORT TRACKS FARTHER NORTH. FOR NOW, LEANED
TOWARD THE NAM/WRF FOR POPS WHICH PLACES SLIGHT CHC TO CHC RANGE
VALUES MAINLY ACROSS NORTHEASTERN PENNSYLVANIA. WE KEPT ABOUT ONE-
HALF INCH OF SNOW ACCUMULATION ACROSS THE POCONOS.
ELSEWHERE, LITTLE TO NOTHING IS EXPECTED WITH THE FRONTAL PASSAGE
OTHER THAN A BAND OF STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS.
SPEAKING OF STRATOCUMULUS, THESE WILL BE AROUND TODAY ESPECIALLY
ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY AS THE
WESTERLY FLOW MAINTAINS ENOUGH MOISTURE UNDER AN INVERSION. THE
FORECAST SOUNDINGS INDICATE WE SHOULD GET RATHER CLOSE TO THE
CONVECTIVE TEMPERATURES TODAY DESPITE THE LOWER LEVELS BEING
RATHER DRY. THIS SHOULD RESULT IN AT LEAST SOME STRATOCUMULUS
BELOW SOME HIGHER CLOUDS ACROSS THE REST OF THE CWA, WHICH MAY
RESULT IN VARYING CLOUD COVER THROUGH THE DAY.
A WESTERLY WIND WILL CONTINUE TO BE ON THE BRISK SIDE AS VERTICAL
MIXING IS MAINTAINED. THE WINDS HOWEVER ARE EXPECTED TO BE LESS
THAN WHAT WAS OBSERVED YESTERDAY, AND SETTLE DOWN LATER IN THE
AFTERNOON. AS FOR TEMPERATURES, WE MAINLY TOOK AN EVENLY WEIGHTED
BLEND OF THE MOS GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE AFOREMENTIONED SECONDARY COLD FRONT WILL CONTINUE TO SETTLE
SOUTHWARD BEFORE POTENTIALLY DISSIPATING. THERE COULD BE SOME
LINGERING FLURRIES OR A SNOW SHOWER WITH IT ESPECIALLY IN THE
WESTERN ZONES. HOWEVER, ANYTHING WITH IT SHOULD BE WANING WITH A
SOUTHERN EXTENT AS THE OVERALL LIFT AND MOISTURE DWINDLES AS WELL
AS A GRADUAL INCREASE IN THE SUBSIDENCE AND A LESS FAVORABLE FETCH
FROM THE LAKES. THEREFORE, KEPT THE SKY COVER A BIT HIGHER FOR A
TIME WITHIN A WEST TO EAST BAND WITH THE SOUTHBOUND FRONT. THERE
MAY BE ENOUGH MID LEVEL MOISTURE AROUND TO KEEP SOME CLOUDS
AROUND, BUT OVERALL AN EVEN DRIER PUSH OF AIR FROM THE NORTH
SHOULD RESULT IN SOME SCATTERING IN THE CLOUDS ESPECIALLY SOUTH
AND EAST OF THE PHILADELPHIA METRO AREA.
AS STRENGTHENING HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN CANADA
AND THE EASTERN GREAT LAKES LATE TONIGHT, THE NORTHERLY FLOW WILL
DRIVE A COLDER AIR MASS OVER OUR AREA. THE 850 MB TEMPERATURES ARE
FORECAST TO DROP TO NEAR -15C OVERNIGHT. THERE IS SOMEWHAT OF A
PRESSURE GRADIENT REMAINING DURING THE NIGHT, HOWEVER THE OVERALL
MIXING SHOULD TEND TO BECOME MUCH MORE REDUCED AS THE NIGHT WEARS
ON. THIS WILL RESULT IN A RATHER COLD NIGHT ACROSS THE ENTIRE
AREA.
AS FOR TEMPERATURES, WE GENERALLY WENT WITH A BLEND OF THE
GFS/NAM MOS WITH SOME TWEAKS MAINLY FOR THE TYPICALLY COLDER
LOCALES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MOSTLY CLEAR AND COLD WEATHER IS ANTICIPATED FOR SUNDAY AND
SUNDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS OUR REGION. MAXIMUM
TEMPERATURES SHOULD RANGE FROM THE UPPER TEENS IN THE POCONOS TO
THE MIDDLE 30S IN SOUTHERN DELAWARE. FOR SUNDAY NIGHT, READINGS
ARE FORECAST TO DROP INTO THE TEENS THROUGHOUT MOST OF OUR REGION
WITH A LIGHT WIND AND GOOD RADIATIVE CONDITIONS.
THE MID LEVEL RIDGE AXIS IS FORECAST TO PASS OVERHEAD ON MONDAY
MORNING WITH STRONG WARM ADVECTION DEVELOPING ALOFT. FROM MONDAY
INTO MONDAY EVENING WE SHOULD SEE AN INCREASE IN HIGH, THEN MID
LEVEL CLOUDS.
ON MONDAY NIGHT, A DEVELOPING JET AROUND 850 HPA WILL BE LOCATED
OVER THE OHIO RIVER VALLEY, AHEAD OF OUR NEXT WEATHER SYSTEM
APPROACHING FROM THE WEST. THE JET SHOULD DROP SLOWLY
SOUTHEASTWARD, POINTING SQUARELY AT OUR FORECAST AREA. IT WILL ACT
TO DIRECT MOISTURE INTO OUR REGION RATHER QUICKLY. MONDAY NIGHT
SHOULD START DRY. HOWEVER, PRECIPITATION IS EXPECTED TO OVERSPREAD
OUR REGION. WITH COLD DRY AIR IN PLACE AT THE LOW LEVELS, WE MAY
VERY WELL ENCOUNTER PRECIPITATION TYPE ISSUES, MAINLY IN EASTERN
PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY. BASED ON THEN
EXPECTED TEMPERATURE PROFILES AND THE ANTICIPATION THAT STRONG
WARM ADVECTION ALOFT WILL CONTINUE, IT APPEARS AS THOUGH WE MAY
SEE A MIX OF MAINLY SLEET AND FREEZING RAIN IN OUR NORTHWESTERN
COUNTIES. A LITTLE SNOW IS ALSO POSSIBLE. HOWEVER, THAT WILL
DEPEND UPON A SOMEWHAT WEAKER INITIAL PUSH OF WARM AIR ALOFT THAN
MOST OF THE GUIDANCE IS CURRENTLY SUGGESTING. ON THE COASTAL
PLAIN, IT LOOKS AS THOUGH TEMPERATURES AT THE SURFACE AND ALOFT
WILL SUPPORT ALL RAIN ON MONDAY NIGHT.
AS THE WARM ADVECTION CONTINUES ON TUESDAY. THE WINTRY
PRECIPITATION SHOULD CHANGE TO ALL RAIN. THE RAIN MAY BECOME
SHOWERY DURING THE AFTERNOON. WE ARE NOT PARTICULARLY CONFIDENT IN
THE TEMPERATURE FORECAST FOR TUESDAY. THE LOW LEVEL COLD AIR MAY
BE A LITTLE MORE STUBBORN UP NORTH THAN OUR FORECAST INDICATES.
ALSO, IN OUR FAR SOUTHERN COUNTIES, SIGNIFICANT BREAKS IN THE
CLOUD COVER COULD RESULT IN TEMPERATURES HIGHER THAN THOSE WE ARE
FORECASTING.
A COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE ON TUESDAY NIGHT
WITH HIGH PRESSURE AND DRY WEATHER FOLLOWING FOR WEDNESDAY AND
THURSDAY. THE SOURCE REGION FOR THE AIR MASS WILL BE MORE FROM THE
WEST THAN THE NORTHWEST, SO TEMPERATURES WILL LIKELY BE ABOUT
NORMAL FOR THIS TIME OF THE YEAR.
A WEAK FRONTAL BOUNDARY MAY DROP INTO OUR REGION FROM THE
NORTHWEST LATE IN THE WEEK. FOR NOW, WE HAVE SIMPLY INDICATE A
SLIGHT CHANCE OF SNOW SHOWERS WITH THE FEATURE.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A STRONG LOW PRESSURE SYSTEM IN THE CANADIAN MARITIMES THROUGH
TONIGHT WILL MAINTAIN A WEST TO NORTHWEST FLOW ACROSS OUR AREA. A
SECONDARY FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA FROM LATER
THIS MORNING THROUGH THE EVENING. THERE IS NOT MUCH FORCING AND
MOISTURE WITH THIS BOUNDARY, HOWEVER THERE ARE SOME HINTS IN THE
MODEL GUIDANCE THAT MOISTURE FROM THE EASTERN GREAT LAKES GETS
PULLED EASTWARD WITH THIS FRONT. THIS MAY RESULT IN ENOUGH LOW-
LEVEL CONVERGENCE TO ALLOW FOR A NARROW BAND OF FLURRIES OR
HEAVIER SNOW SHOWERS ACROSS THE NORTHERN PORTION OF PENNSYLVANIA
INTO NORTHWESTERN NEW JERSEY. AS A RESULT, A FEW SNOW SHOWERS MAY
GET TO AT LEAST KABE. GIVEN THE LOWER CONFIDENCE WITH THE TIMING
AND EXTENT OF ANY SNOW SHOWERS, WE DID NOT CARRY A MENTION IN THE
TAFS AT THIS TIME.
THE COLD WESTERLY FLOW COMBINED WITH ENOUGH MOISTURE TRAPPED
UNDER AN INVERSION IS HELPING TO PULL STRATOCUMULUS DOWN INTO
PARTS OF THE AREA. THIS IS EXPECTED TO CONTINUE WITH AT LEAST
BROKEN CEILINGS AROUND 4,000 FEET, MAINLY FROM THE KPHL METRO ON
NORTH AND WESTWARD. THE WINDS HAVE BEEN DECOUPLING SOME WITH GUSTS
DROPPING OFF AT SOME OF THE TERMINALS EARLY THIS MORNING. ALL OF
OUR TERMINALS ARE EXPECTED TO HAVE SOME GUSTS IN THE 20-25 KNOT
RANGE FOR AWHILE TODAY BEFORE SETTLING DOWN LATER IN THE AFTERNOON
AND TONIGHT. THE AFOREMENTIONED BOUNDARY SHOULD MAINTAIN SOME
STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS WITH IT AS IT DROPS
SOUTHWARD THROUGH THE EVENING. THIS BOUNDARY WILL ALSO TURN THE
SURFACE WINDS MORE TO THE NORTHWEST THROUGH TONIGHT.
OUTLOOK...
DRY WEATHER AND VFR CONDITIONS ARE FORECAST FOR SUNDAY AND
MONDAY. PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION FROM
THE WEST ON MONDAY NIGHT AND IT SHOULD CONTINUE INTO TUESDAY. THE
PRECIPITATION MAY BEGIN AS A WINTRY MIX ON MONDAY NIGHT AT KRDG,
KABE AND PERHAPS KTTN. ALL RAIN IS ANTICIPATED FOR KPHL, KPNE,
KILG, KMIV AND KACY.
A COLD FRONT IS EXPECTED TO PASS THROUGH OUR REGION ON TUESDAY
NIGHT, BRINGING AND END TO THE RAIN. HIGH PRESSURE AND DRY WEATHER
SHOULD FOLLOW FOR WEDNESDAY.
&&
.MARINE...
AN INTENSE SURFACE LOW OVER THE CANADIAN MARITIMES WILL CONTINUE
TO CIRCULATE A COLD AIR MASS OVER OUR REGION UNDER A WESTERLY FLOW.
A SECONDARY COLD FRONT WILL SWING AROUND THIS LOW AND SETTLE
SOUTHWARD ACROSS THE AREA TODAY INTO TONIGHT. SOME COLDER AIR WILL
ADVECT INTO THE AREA BEHIND THIS FRONT THROUGH TONIGHT. THE
PRESSURE GRADIENT REMAINS TIGHTENED TODAY INTO TONIGHT, HOWEVER
THE OVERALL WIND FIELD IS FORECAST TO LESSEN WITH TIME. THIS HAS
ALREADY BEEN NOTED AS THE WINDS HAVE BEEN GRADUALLY COMING DOWN
EARLY THIS MORNING. WHILE THERE COULD BE SOME UPTICK FOR A TIME
THIS MORNING DUE TO A LITTLE BETTER MIXING, IT MIGHT END UP BEING
A MORE MARGINAL SETUP FOR A SMALL CRAFT ADVISORY /ESPECIALLY
ACROSS THE SOUTHERN ZONES/. BASED ON THE SOUNDINGS AND TO ALLOW
FOR SOME WIGGLE ROOM, THE ADVISORY WILL RUN UNTIL 18Z FOR ALL
AREAS. THIS CAN ALWAYS BE CANCELLED EARLY. OTHERWISE, A DOWNWARD
TREND IN THE SEAS AND WINDS UNDER ADVISORY CRITERIA ARE EXPECTED
TONIGHT AS HIGH PRESSURE EDGES CLOSER.
WITH THE NORTHWEST FLOW PERSISTING INTO SUNDAY, WIND GUSTS TO
AROUND 25 KNOTS ARE POSSIBLE AT THAT TIME. HIGH PRESSURE SHOULD
BUILD ACROSS THE COASTAL WATERS OF NEW JERSEY AND DELAWARE ON
SUNDAY NIGHT AND EARLY MONDAY, BRINGING RELATIVELY TRANQUIL
CONDITIONS.
WIND SPEEDS ARE FORECAST TO BE ON THE INCREASE AGAIN LATE ON
MONDAY AS OUR NEXT WEATHER SYSTEM BEGINS TO APPROACH FROM THE
WEST. A BRISK SOUTHERLY FLOW IS ANTICIPATED FOR MONDAY NIGHT AND
TUESDAY WITH WIND GUSTS IN EXCESS OF 25 KNOTS, ALONG WITH WAVE
HEIGHTS ON OUR OCEAN WATERS BUILDING TO 5 TO 8 FEET.
A COLD FRONT IS EXPECTED TO PASS ACROSS THE REGION ON TUESDAY
NIGHT. THE WIND DIRECTION WILL LIKELY SHIFT TO THE WEST. HOWEVER,
GUSTS NEAR 25 KNOTS WILL REMAIN POSSIBLE INTO WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-
431-450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION...updated for aviation section
NWS TALLAHASSEE FL
535 AM EST Sat Jan 14 2012
.SYNOPSIS...
08Z water vapor and H4 RUC analysis shows an upper level pattern
consisting of longwave troughing over much of the inter-mountain
west, followed downstream by longwave troughing over much of the
CONUS east of the continental divide. A series of shortwaves
beginning to arrive along the British Columbia coastline will slowly
break down the western U.S. ridge during the upcoming weekend which
will lead to eventual height rises and an overall warmup for the
eastern states by the early portion of next week.
For now however, watching a shortwave impulse rounding the base of
the main eastern trough over the SE states early this morning. The
trough axis is just now exiting east of our area, seen with an
expanding area of subsidence/drying overhead on WV imagery. A final
piece of energy is sliding down the backside of the trough through
the mid-section of the country. This energy will slide to our north
tonight allowing height rises in its wake for Sunday.
At the surface, 1028mb high pressure centered along the TX/LA coasts
continues to build east into our forecast area. As the ridge expands
eastward, the local gradient has been slowly weakening allowing for
an increasingly efficient radiational cooling setup. Still
anticipate a widespread light freeze by sunrise away from the
immediate coast. A few isolated and normally colder locations may
still briefly reach hard freeze criteria in the hour or two
surrounding sunrise.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
Today,
Subsidence behind the departing shortwave this morning will help
promote mostly sunny skies through the day. However, a slight
re-enforcing shot of CAA...especially above the surface will keep
temperatures a bit below normal. At the surface, high pressure will
continue to expand eastward with a high center forming over the
coastal waters by the later afternoon/evening hours. To our north, a
weak surface reflection/low associated with the final shortwave
impulse will translate quickly from MO this afternoon, to the TN
valley this evening. Associated with this feature will be a weak
cold front that will cross northern AL/GA and into the Carolinas.
Although this cold front will not directly pass through our area, it
will have an influence of somewhat tightening the gradient over our
northern zones later today/this evening. The tighter gradient may
have an impact on temperatures tonight. Before that, afternoon temps
today are expected to top out in the mid/upper 50s.
Tonight,
As mentioned above, some uncertainly with regards to temperatures
relating to how rapidly the gradient will collapse again over our
northern/NE zones in the wake of a passing cold front/trough. The
impact looks to be least along and south of the I-10 corridor where
proximity to the eastward extension of the surface ridge should set
up good radiational cooling conditions early. The temperatures drop
may be slower this evening further to the north, however the
GFS/ECMWF both show a quick exit of the trough and the potential for
late night de-coupling. Therefore, will not deviate far from a
MET/MAV blend for overnight lows. Generally looking for lows in the
low/mid 30s inland and mid/upper 30s at the coast. Does appear that
any location which do reach or drop just below freezing will not do
so until right around sunrise, with a fairly short duration of near
freezing temps. If the tighter gradient holds longer than numerical
guidance currently suggest, then low temps would not be quite as
cold for areas north of KTLH and KVLD.
Sunday/Sunday night,
Very pleasant day upcoming for the second half of the weekend.
Rising heights over-top a strong surface ridge will provide the
region with dry and seasonable conditions. Winds will be on the
light side, which will slow the overall diurnal mixing, however
should still be able to reach afternoon highs very close to
climatology in the 59-64 range. Sunday night the surface ridge will
exit to our east allowing a slow increase in gradient and also low
level moisture. Current guidance still suggest a cool overnight with
lows in the mid 30s inland to the low 40s at the coast.
Monday,
Stacked ridging will allow temperatures to finally rise above
normal for most locations. Still not anticipating all that efficient
a mixing environment, and therefore will likely not realize the full
potential of the column that 850mb temps around 10C would suggest.
However, not too many will be complaining as temps rise into the
upper 60s to near 70 under partly sunny skies. The SE/S flow is
likely to keep immediate coastal areas a bit cooler, especially
along the Apalachee Bay coastline where shelf water temps are in
the upper 50s.
&&
.LONG TERM (Monday Night through next Friday)...
The large scale longwave pattern commences fairly amplified. This is
highlighted in the Nrn stream by troughing across Plains and weak
ridging in between. Srn stream with weak troughing Desert SW and
weak ridging elsewhere. At surface, high along Carolina coast
ridging swwd into Cntrl Gulf. Low in Srn Great Lakes with cold front
Swwd across Wrn TN Valley and into TX.
During the rest of the period, Plains upper trough digs rapidly SEWD
accompanied by shortwave and merges with Desert SW Trough crossing
the Nrn Gulf Tues into Tues night. In response, Srn stream upper
ridge shunted offshore. At surface, this trough pushes surface low
to Srn Great Lakes kicking high further into Atlc. Assocd cold front
with limited instability dragged rapidly Sewd with deep sly flow
setup from Gulf. GFS and ECMWF similar in timing and intensity of
front, but both noticeably slower than 24 hrs ago, pushing thru Wrn
CWA late Tues night exiting Ern most zones Wed morning bringing sct
shwrs and possibly a few tstms.
Trough pushes into Atlc beginning Wed night. In its wake, NWLY to
weakly zonal steering flow once again dominates local area as
strong high builds SEWD from Srn Plains spreading a reinforcing shot
of cold and very dry offshore air across local region Wed into late
Thurs. However coldest air remains well to our north so not
expecting a solid freeze event. By early Fri, models consistent with
next albeit weak shortwave that helps developing surface low which
moves moves newd into Lwr MS Valley dragging trailing cold front to
Wrn Gulf. Locally, this pushes the dry airmass EWD and high offshore
increasing onshore flow and clouds beginning Fri night.
Forecast will show low-mid sct pops Tues aftn especially NW third
expanding everywhere on Wed morning down to wdly sct-low sct Wed
aftn. Otherwise nil pops thru period. Ahead of the front min temps
will be around 10 degrees above climo Mon and Tues nights dropping
to at or below climo Wed night and may reach freezing in coldest
locales then inching to slightly above climo on Thu night. Max temps
commence at least 10 degrees above climo on Tues dropping to at or
slightly above climo on Wed then inching up to a few degrees each
day thru Fri. Average inland min/max temps are 39/62
&&
.MARINE...
High pressure will build over the coastal waters today allowing
winds and seas to subside. A brief surge of westerly winds may
approach cautionary levels overnight into early Sunday morning
before quickly diminishing by the afternoon. The ridge of high
pressure will then move east of our region Sunday night allowing
winds to come around to the east and southeast and increase to
moderate levels for the early portion of next week. A weak cold
front is schedule to cross the northeast Gulf Tuesday night or
Wednesday with a shift back to offshore flow in its wake.
&&
.AVIATION (through 12Z Sunday)...
VFR Conditions with mainly clear skies through the period. Calm
winds increase to west to northwest around 5 mph after sunrise,
then calm again after sunset.
&&
.FIRE WEATHER...
Expect a faster warmup and higher afternoon temperatures today
compared to yesterday. Therefore with a persistent dry airmass
expect around 4 hour durations of RH below 25% in our Alabama and
Georgia zones, altho ern counties of GA iffy. But...with warning
already in effect will elect to keep it everywhere and have day
shift reevaluate. For our Florida zones, altho critical humidities
will be realized, latest dispersions as well as ERC and 20 foot
winds should remain under critical levels. Therefore inherited watch
has been discontinued. Airmass should moisten slightly on Sunday
precluding red flag conditions over AL/GA. Once again low humidities
in FL will be offset by ERC...dispersion and winds below critical
levels. Red flag conditions are not anticipated during the upcoming
work week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 57 32 62 33 68 / 0 0 0 0 0
Panama City 57 40 62 43 61 / 0 0 0 0 0
Dothan 59 35 59 36 69 / 0 0 0 0 0
Albany 57 32 59 34 70 / 0 0 0 0 0
Valdosta 56 33 60 35 68 / 0 0 0 0 0
Cross City 58 31 64 34 70 / 0 0 0 0 0
Apalachicola 56 36 61 41 60 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Red Flag Warning from Noon today to 5 PM CST this afternoon for
Coffee-Dale-Geneva-Henry-Houston.
GA...Red Flag Warning from 1 PM this afternoon to 6 PM EST this
evening for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-
Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier-
Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole-
Terrell-Thomas-Tift-Turner-Worth.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
335 AM EST Sat Jan 14 2012
.SYNOPSIS...
08Z water vapor and H4 RUC analysis shows an upper level pattern
consisting of longwave troughing over much of the inter-mountain
west, followed downstream by longwave troughing over much of the
CONUS east of the continental divide. A series of shortwaves
beginning to arrive along the British Columbia coastline will slowly
break down the western U.S. ridge during the upcoming weekend which
will lead to eventual height rises and an overall warmup for the
eastern states by the early portion of next week.
For now however, watching a shortwave impulse rounding the base of
the main eastern trough over the SE states early this morning. The
trough axis is just now exiting east of our area, seen with an
expanding area of subsidence/drying overhead on WV imagery. A final
piece of energy is sliding down the backside of the trough through
the mid-section of the country. This energy will slide to our north
tonight allowing height rises in its wake for Sunday.
At the surface, 1028mb high pressure centered along the TX/LA coasts
continues to build east into our forecast area. As the ridge expands
eastward, the local gradient has been slowly weakening allowing for
an increasingly efficient radiational cooling setup. Still
anticipate a widespread light freeze by sunrise away from the
immediate coast. A few isolated and normally colder locations may
still briefly reach hard freeze criteria in the hour or two
surrounding sunrise.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
Today,
Subsidence behind the departing shortwave this morning will help
promote mostly sunny skies through the day. However, a slight
re-enforcing shot of CAA...especially above the surface will keep
temperatures a bit below normal. At the surface, high pressure will
continue to expand eastward with a high center forming over the
coastal waters by the later afternoon/evening hours. To our north, a
weak surface reflection/low associated with the final shortwave
impulse will translate quickly from MO this afternoon, to the TN
valley this evening. Associated with this feature will be a weak
cold front that will cross northern AL/GA and into the Carolinas.
Although this cold front will not directly pass through our area, it
will have an influence of somewhat tightening the gradient over our
northern zones later today/this evening. The tighter gradient may
have an impact on temperatures tonight. Before that, afternoon temps
today are expected to top out in the mid/upper 50s.
Tonight,
As mentioned above, some uncertainly with regards to temperatures
relating to how rapidly the gradient will collapse again over our
northern/NE zones in the wake of a passing cold front/trough. The
impact looks to be least along and south of the I-10 corridor where
proximity to the eastward extension of the surface ridge should set
up good radiational cooling conditions early. The temperatures drop
may be slower this evening further to the north, however the
GFS/ECMWF both show a quick exit of the trough and the potential for
late night de-coupling. Therefore, will not deviate far from a
MET/MAV blend for overnight lows. Generally looking for lows in the
low/mid 30s inland and mid/upper 30s at the coast. Does appear that
any location which do reach or drop just below freezing will not do
so until right around sunrise, with a fairly short duration of near
freezing temps. If the tighter gradient holds longer than numerical
guidance currently suggest, then low temps would not be quite as
cold for areas north of KTLH and KVLD.
Sunday/Sunday night,
Very pleasant day upcoming for the second half of the weekend.
Rising heights over-top a strong surface ridge will provide the
region with dry and seasonable conditions. Winds will be on the
light side, which will slow the overall diurnal mixing, however
should still be able to reach afternoon highs very close to
climatology in the 59-64 range. Sunday night the surface ridge will
exit to our east allowing a slow increase in gradient and also low
level moisture. Current guidance still suggest a cool overnight with
lows in the mid 30s inland to the low 40s at the coast.
Monday,
Stacked ridging will allow temperatures to finally rise above
normal for most locations. Still not anticipating all that efficient
a mixing environment, and therefore will likely not realize the full
potential of the column that 850mb temps around 10C would suggest.
However, not too many will be complaining as temps rise into the
upper 60s to near 70 under partly sunny skies. The SE/S flow is
likely to keep immediate coastal areas a bit cooler, especially
along the Apalachee Bay coastline where shelf water temps are in
the upper 50s.
&&
.LONG TERM (TUESDAY THROUGH NEXT SATURDAY)...
The large scale longwave pattern commences fairly amplified. This is
highlighted in the Nrn stream by troughing across Plains and weak
ridging in between. Srn stream with weak troughing Desert SW and
weak ridging elsewhere. At surface, high along Carolina coast
ridging swwd into Cntrl Gulf. Low in Srn Great Lakes with cold front
Swwd across Wrn TN Valley and into TX.
During the rest of the period, Plains upper trough digs rapidly SEWD
accompanied by shortwave and merges with Desert SW Trough crossing
the Nrn Gulf Tues into Tues night. In response, Srn stream upper
ridge shunted offshore. At surface, this trough pushes surface low
to Srn Great Lakes kicking high further into Atlc. Assocd cold front
with limited instability dragged rapidly Sewd with deep sly flow
setup from Gulf. GFS and ECMWF similar in timing and intensity of
front, and about six hours slower than 24 hrs ago, pushing thru Wrn
CWA Tues night exiting Ern most zones Wed morning bringing sct shwrs
and possibly a few tstms.
Trough pushes into Atlc beginning Wed night. In its wake, NWLY
steering flow once again dominates local area as strong high builds
SEWD from Srn Plains spreading a reinforcing shot of cold and very
dry offshore air across local region Wed into late Thurs. However
coldest air remains well to our north so not expecting a solid
freeze event. By early Fri, models consistent with next albeit weak
shortwave that helps developing surface low which moves moves newd
into Lwr MS Valley dragging trailing cold front to Wrn Gulf.
Locally, this pushes the dry airmass EWD and high offshore
increasing onshore flow and clouds beginning Fri night.
Forecast will show low-mid sct pops Tues aftn especially NW third
expanding everywhere on Wed morning down to wdly sct-low sct Wed
aftn. Otherwise nil pops thru period. Ahead of the front min temps
will be around 10 degrees above climo Mon and Tues nights dropping
to at or below climo Wed night and may reach freezing in coldest
locales then inching to slightly above climo on Thu night. Max temps
commence at least 10 degrees above climo on Tues dropping to at or
slightly above climo on Wed then inching up to a few degrees each
day thru Fri. Average inland min/max temps are 39/62.
&&
.MARINE...
High pressure will build over the coastal waters today allowing
winds and seas to subside. A brief surge of westerly winds may
approach cautionary levels overnight into early Sunday morning
before quickly diminishing by the afternoon. The ridge of high
pressure will then move east of our region Sunday night allowing
winds to come around to the east and southeast and increase to
moderate levels for the early portion of next week. A weak cold
front is schedule to cross the northeast Gulf Tuesday night or
Wednesday with a shift back to offshore flow in its wake.
&&
.AVIATION (through 06Z Sunday)...
VFR Conditions with mainly clear skies through the period. Calm
winds increase to west to northwest around 5 mph after sunrise,
then calm again after sunset.
&&
.FIRE WEATHER...
Expect a faster warmup and higher afternoon temperatures today
compared to yesterday. Therefore with a persistent dry airmass
expect around 4 hour durations of RH below 25% in our Alabama and
Georgia zones, altho ern counties of GA iffy. But...with warning
already in effect will elect to keep it everywhere and have day
shift reevaluate. For our Florida zones, altho critical humidities
will be realized, latest dispersions as well as ERC and 20 foot
winds should remain under critical levels. Therefore inherited watch
has been discontinued. Airmass should moisten slightly on Sunday
precluding red flag conditions over AL/GA. Once again low humidities
in FL will be offset by ERC...dispersion and winds below critical
levels. Red flag conditions are not anticipated during the upcoming
work week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 57 32 62 33 68 / 0 0 0 0 0
Panama City 57 40 62 43 61 / 0 0 0 0 0
Dothan 59 35 59 36 69 / 0 0 0 0 0
Albany 57 32 59 34 70 / 0 0 0 0 0
Valdosta 56 33 60 35 68 / 0 0 0 0 0
Cross City 58 31 64 34 70 / 0 0 0 0 0
Apalachicola 56 36 61 41 60 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Red Flag Warning from Noon today to 5 PM CST this afternoon for
Coffee-Dale-Geneva-Henry-Houston.
GA...Red Flag Warning from 1 PM this afternoon to 6 PM EST this
evening for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-
Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier-
Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole-
Terrell-Thomas-Tift-Turner-Worth.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1136 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 921 AM CST SAT JAN 14 2012
15Z SURFACE CHART SHOWS 1014MB LOW OVER CENTRAL MISSOURI...WITH
BAND OF LIGHT SNOW NORTH OF THIS FEATURE FROM NORTHERN MISSOURI
INTO SOUTH-CENTRAL ILLINOIS. BASED ON RADAR IMAGERY AND AREA
SURFACE OBS...THE SNOW HAS PRIMARILY BEEN CONFINED TO LOCATIONS
ALONG AND SOUTH OF A MACOMB...TO LINCOLN...TO CHARLESTON-MATTOON
LINE. AS THE LOW TRACKS E/SE...THE BAND OF SNOW WILL CONTINUE TO
IMPACT MAINLY THE SOUTHERN HALF OF THE KILX CWA THROUGH AT LEAST
EARLY AFTERNOON. WEAK LIFT AND LIMITED MOISTURE WILL LIMIT ANY
ACCUMULATIONS TO ONLY A COUPLE TENTHS OF AN INCH AT BEST. FURTHER
NORTHWEST...ANOTHER WEAK SHORT-WAVE IS NOTED IN WATER VAPOR
IMAGERY TRACKING ACROSS THE EASTERN DAKOTAS. THIS FEATURE WILL
APPROACH FROM THE NORTHWEST LATER THIS AFTERNOON INTO THE
EVENING...BRINGING A FEW FLURRIES TO THE AREA. HAVE UPDATED THE
FORECAST FOR TODAY TO INCLUDE 30-40 POPS FOR LIGHT SNOW ACROSS THE
SOUTHERN CWA...WITH JUST SCATTERED FLURRIES TO THE NORTH. HAVE
ADDED FLURRIES ACROSS THE BOARD FOR THE EVENING HOURS IN ASSOCIATION
WITH THE SECONDARY WAVE. ZONE UPDATE HAS ALREADY BEEN ISSUED.
&&
.AVIATION...
ISSUED 1136 AM CST SAT JAN 14 2012
LIGHT SNOW WILL CONTINUE TO IMPACT MOST OF THE TAF SITES FOR THE
NEXT COUPLE OF HOURS...BEFORE GRADUALLY COMING TO AN END BY
MID-AFTERNOON. WILL HANG ON TO LIGHT SNOW THROUGH 19Z/20Z
ACCORDINGLY...EXCEPT AT KPIA WHERE THE SNOW HAS ALREADY ENDED.
CEILINGS WILL HOVER AROUND 3000FT AT THE I-72 TERMINALS UNTIL THE
SNOW ENDS...THEN WILL CLIMB INTO THE VFR CATEGORY LATER THIS
AFTERNOON. A SECONDARY UPPER-LEVEL WAVE CURRENTLY PUSHING INTO
IOWA WILL SKIRT THROUGH THE REGION TONIGHT...BRINGING A PERIOD OF
LOWER CEILINGS AND PERHAPS A FEW SNOW FLURRIES. HAVE LOWERED
CEILINGS BACK DOWN TO AROUND 3000FT AT KPIA BY 03Z...THEN FURTHER
EAST AT KCMI BY 08Z. ONCE THIS WAVE PASSES...MID-LEVEL CLOUD COVER
WILL PERSIST THROUGH 18Z SAT. WINDS WILL INITIALLY BE
LIGHT/VARIABLE THIS AFTERNOON AND TONIGHT...THEN WILL BECOME
SOUTHERLY AT AROUND 10KT SUNDAY MORNING.
BARNES
&&
.PREV DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
921 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 921 AM CST SAT JAN 14 2012
15Z SURFACE CHART SHOWS 1014MB LOW OVER CENTRAL MISSOURI...WITH
BAND OF LIGHT SNOW NORTH OF THIS FEATURE FROM NORTHERN MISSOURI
INTO SOUTH-CENTRAL ILLINOIS. BASED ON RADAR IMAGERY AND AREA
SURFACE OBS...THE SNOW HAS PRIMARILY BEEN CONFINED TO LOCATIONS
ALONG AND SOUTH OF A MACOMB...TO LINCOLN...TO CHARLESTON-MATTOON
LINE. AS THE LOW TRACKS E/SE...THE BAND OF SNOW WILL CONTINUE TO
IMPACT MAINLY THE SOUTHERN HALF OF THE KILX CWA THROUGH AT LEAST
EARLY AFTERNOON. WEAK LIFT AND LIMITED MOISTURE WILL LIMIT ANY
ACCUMULATIONS TO ONLY A COUPLE TENTHS OF AN INCH AT BEST. FURTHER
NORTHWEST...ANOTHER WEAK SHORT-WAVE IS NOTED IN WATER VAPOR
IMAGERY TRACKING ACROSS THE EASTERN DAKOTAS. THIS FEATURE WILL
APPROACH FROM THE NORTHWEST LATER THIS AFTERNOON INTO THE
EVENING...BRINGING A FEW FLURRIES TO THE AREA. HAVE UPDATED THE
FORECAST FOR TODAY TO INCLUDE 30-40 POPS FOR LIGHT SNOW ACROSS THE
SOUTHERN CWA...WITH JUST SCATTERED FLURRIES TO THE NORTH. HAVE
ADDED FLURRIES ACROSS THE BOARD FOR THE EVENING HOURS IN ASSOCIATION
WITH THE SECONDARY WAVE. ZONE UPDATE HAS ALREADY BEEN ISSUED.
BARNES
&&
.AVIATION...
ISSUED 530 AM CST SAT JAN 14 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WEAK
CLIPPER SYSTEM IS MOVING INTO THE SOUTHERN PARTS OF THE AREA THIS
MORNING. THIS IS BRINGING LOWER VFR CIGS AROUND 5KFT INTO THE
AREA. BELIEVE PRIMARY SITES THAT WILL EXPERIENCE CIGS AT THIS
LEVEL WILL BE SPI AND DEC. PIA/BMI/CMI COULD SEE THIS BUT THEY
WILL BE ON THE NORTHERN EDGE OF THE CIGS. SO WILL HAVE SCATTERED
CLOUDS AT 5KFT WITH TEMPO GROUP FOR 4HRS OF POSSIBLE CIGS AT 5KFT.
EXPECT MID LEVEL CIGS OTHERWISE DURING THE MORNING HOURS AT THREE
SITES ALONG I-74. 5KFT CIGS AT SPI AND DEC SHOULD CONTINUE INTO
THE AFTERNOON HOURS. BY THIS AFTERNOON...APPEARS ALL SITES COULD
BE MOSTLY CLEAR SO WILL HAVE SKC AT ALL SITES STARTING AROUND 21Z.
THIS SHOULD LAST INTO THE EVENING HOURS. HOWEVER WITH A RETURN TO
WAA...EXPECT SOME LOWER VFR CIGS AROUND 4KFT DURING THE LATE
EVENING AND OVERNIGHT HOURS. COULD BE LOWER...BUT WILL START WITH
SCATTERED CLOUDS AT 2.5KFT WITH BKN CIGS AT 4KFT...AT ALL SITES.
WIND DIRECTION WILL BE SOUTHERLY TO START BUT AS THE WEAK CLIPPER
SYSTEM MOVES SOUTH OF THE AREA WINDS WILL BECOME EAST...TO
NORTHEAST...AROUND TO NORTHWEST. HOWEVER...WIND SPEEDS WILL BE
LIGHT SO WILL HAVE VARIABLE WINDS AS WELL DURING AFTERNOON AND
EARLY EVENING HOURS. BY OVERNIGHT...SOUTHERLY WINDS WILL RETURN AGAIN.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
530 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 530 AM CST SAT JAN 14 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WEAK
CLIPPER SYSTEM IS MOVING INTO THE SOUTHERN PARTS OF THE AREA THIS
MORNING. THIS IS BRINGING LOWER VFR CIGS AROUND 5KFT INTO THE
AREA. BELIEVE PRIMARY SITES THAT WILL EXPERIENCE CIGS AT THIS
LEVEL WILL BE SPI AND DEC. PIA/BMI/CMI COULD SEE THIS BUT THEY
WILL BE ON THE NORTHERN EDGE OF THE CIGS. SO WILL HAVE SCATTERED
CLOUDS AT 5KFT WITH TEMPO GROUP FOR 4HRS OF POSSIBLE CIGS AT 5KFT.
EXPECT MID LEVEL CIGS OTHERWISE DURING THE MORNING HOURS AT THREE
SITES ALONG I-74. 5KFT CIGS AT SPI AND DEC SHOULD CONTINUE INTO
THE AFTERNOON HOURS. BY THIS AFTERNOON...APPEARS ALL SITES COULD
BE MOSTLY CLEAR SO WILL HAVE SKC AT ALL SITES STARTING AROUND 21Z.
THIS SHOULD LAST INTO THE EVENING HOURS. HOWEVER WITH A RETURN TO
WAA...EXPECT SOME LOWER VFR CIGS AROUND 4KFT DURING THE LATE
EVENING AND OVERNIGHT HOURS. COULD BE LOWER...BUT WILL START WITH
SCATTERED CLOUDS AT 2.5KFT WITH BKN CIGS AT 4KFT...AT ALL SITES.
WIND DIRECTION WILL BE SOUTHERLY TO START BUT AS THE WEAK CLIPPER
SYSTEM MOVES SOUTH OF THE AREA WINDS WILL BECOME EAST...TO
NORTHEAST...AROUND TO NORTHWEST. HOWEVER...WIND SPEEDS WILL BE
LIGHT SO WILL HAVE VARIABLE WINDS AS WELL DURING AFTERNOON AND
EARLY EVENING HOURS. BY OVERNIGHT...SOUTHERLY WINDS WILL RETURN AGAIN.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
236 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 1116 PM CST FRI JAN 13 2012
LOW CLOUDS/FLURRIES HAVE CLEARED THE TAF SITES EXPECT FOR BMI AND
CMI...AND THESE SITES SHOULD CLEAR OUT IN THE NEXT HOUR OR SO. OUT
WEST...THE NEXT CLIPPER IS ALREADY SPREADING CLOUDS AND SOME RADAR
RETURNS ACROSS THE WESTERN HALF OF IA AND NORTHWESTERN MO. THE
SURFACE REFLECTION NOW OVER EASTERN NEB WILL MOVE ALONG THE LOW
LEVEL BAROCLINIC ZONE FROM MORTHWEST TO SOUTHEAST ACROSS MO THEN TO
MIDDLE TN BY 00Z SUN. ALTHOUGH THE SHORT RANGE MODELS MOSTLY KEEP
THE LIGHT SNOW WITH THIS SYSTEM TO THE SOUTHWEST OF SPI...IT WILL BE
A CLOSE ENOUGH SHAVE TO CONTINUE WITH VCSH THERE AROUND 12Z-18Z.
WILL KEEP OTHER TERMINALS DRY WITH JUST SOME SCATTERED STRATOCU AND
BROKEN MID/HIGH CLOUDS. AN UPPER SHEAR AXIS EXTENDS BACK FROM THE
NEB CLIPPER TO NORTHERN ND...WHICH WILL TAKE A MORE NORTHERLY TRACK
ACROSS THE LOWER GREAT LAKES WITH LITTLE SURFACE REFLECTION. MID
LEVEL LIFT/FRONTOGENESIS IS FORECAST TO BRUSH NORTHERN IL AFTER 00Z
SUN...BUT MOST OF THE PRECIPITATION SHOULD BE TO THE NORTH OF
PIA/BMI. SURFACE WINDS THIS PERIOD WILL BE QUITE VARIABLE...BUT LESS
THAN 10 KT MOST OF THE TIME AS THE SURFACE LOW MOVES SOUTH OF THE
AREA AND A WEAK PRESSURE GRADIENT PREVAILS TO THE NORTH.
04
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
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..
&&
.AVIATION.../ISSUED 1158 AM CST SAT JAN 14 2012/
AN AREA OF LIGHT SNOW OR FLURRIES FROM WESTERN IA INTO EASTERN MN
WILL MOVE EAST ACROSS THIS AFTERNOON AND THIS EVENING. MVFR CIGS/
VSBYS WILL BE ASSOCIATED WITH THE SNOW AT KCID/KDBQ/KMLI LATE THIS
AFTERNOON AND THIS EVENING WITH MAINLY VFR CIGS/VSBYS AT KBRL.
CIGS/VSBYS TO IMPROVE TO VFR BY LATE EVENING OR EARLY SUNDAY MORNING.
LIGHT SOUTHERLY WINDS THIS AFTERNOON THROUGH LATE TONIGHT WILL BE
INCREASING TO AROUND 10KTS SUNDAY MORNING. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
DLF/12
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1106 PM CST FRI JAN 13 2012
.AVIATION...
THE SMALL LOW PRESSURE SYSTEM THAT WAS EXPECTED TO BRING LIGHT
SNOW AND MVFR CIGS TO THE AREA TOMORROW NO LONGER SEEMS TO BE A
THREAT AS IT PASSES MAINLY OVER WESTERN IOWA. THE ONLY REAL THREAT
FOR THESE CONDITIONS NOW SEEMS TO BE TOWARDS 00Z IN NORTHEAST
IOWA...BUT THAT THREAT SEEMS VERY LOW RIGHT NOW. THUS LIGHT WINDS
AND VFR WEATHER SHOULD PERSIST AT ALL SITES THROUGH 06Z/15. ALL
CIGS TODAY SHOULD BE 5000 TO 8000 FT.
&&
.PREV DISCUSSION... /ISSUED 327 PM CST FRI JAN 13 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN EXTRATROPICAL CYCLONE IN SOUTHEAST CANADA
WITH NUMEROUS TROFS FROM THE TENNESSEE VALLEY BACK INTO THE UPPER
MIDWEST. RADAR TRENDS THROUGH MID AFTERNOON CONTINUE TO SHOW PLENTY
OF FLURRIES AND LIGHT SNOW OVER THE MID MISSISSIPPI VALLEY. CLEARING
UNDER THE CYCLONIC FLOW WAS MAKING SLOW BUT STEADY PROGRESS EASTWARD.
18Z SFC ANALYSIS HAS A COLD FRONT FROM THE EASTERN GREAT LAKES BACK
INTO NORTHEAST ILLINOIS WITH A HIGH PRESSURE RIDGE FROM MINNESOTA
INTO EASTERN TEXAS. A CHINOOK WARM FRONT WAS OVER THE EASTERN PARTS
OF THE DAKOTAS AND NEBRASKA. A WARM FRONT ASSOCIATED WITH THE NEXT
CLIPPER SYSTEM WAS MOVING OUT OF THE NORTHERN ROCKIES. DEW POINTS
UNDER THE HIGH PRESSURE RIDGE WERE IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO. OTHERWISE DEW POINTS WERE IN THE TEENS AND 20S ACROSS
THE MIDWEST AND PLAINS.
SHORT TERM...TONIGHT AND SATURDAY...
LIGHT SNOW WILL CONTINUE THROUGH LATE AFTERNOON BUT WILL TAPER TO
FLURRIES ONCE SUNSET OCCURS. RUC TRENDS CONTINUE TO SHOW WEAK F
VECTOR CONVERGENCE AND WEAK FRONTOGENETICAL FORCING WILL REMAIN
ACROSS THE AREA INTO THE EARLY EVENING. THAT COMBINED WITH THE
SHALLOW ARCTIC AIR MASS AND A VORT MAX MOVING THROUGH THE CWFA WILL
ALLOW FLURRIES TO PERSIST THROUGH MID EVENING.
CLEARING WILL OCCUR FROM WEST TO EAST DURING THE EVENING AND
OVERNIGHT HOURS. TEMPERATURES SHOULD DROP QUICKLY ONCE CLEARING
OCCURS DUE TO THE SNOW COVER AND LIGHT WINDS. AFTER MIDNIGHT...WAA
CLOUDS FROM THE APPROACHING CLIPPER SYSTEM WILL MOVE INTO THE AREA
AND LIKELY ALLOW TEMPERATURES TO BOTTOM OUT AND SLOWLY RISE.
AFTER 3 AM...ALL MODELS SHOW F VECTOR CONVERGENCE DEVELOPING AGAIN
WITH COLLAPSING CONDENSATION PRESSURE DEFICITS ALONG WITH AN
INCREASE IN FRONTOGENETICAL FORCING. MOISTURE WITH THIS CLIPPER
SYSTEM IS LIMITED BUT FLURRIES AND LIGHT SNOW SHOULD BREAK OUT PRIOR
TO DAWN GENERALLY WEST OF A KIIB TO KPPQ LINE. SCHC/CHC POPS WERE
DONE DUE TO THE LIMITED MOISTURE BUT MAY NEED TO BE RAISED IN THE
EXTREME WEST AND SOUTHWEST PARTS OF THE CWFA.
THE WAA PRECIPITATION WING OF THE CLIPPER SYSTEM WILL MOVE ACROSS
THE WESTERN HALF OR TWO THIRDS OF THE CWFA SATURDAY MORNING.
CONDENSATION PRESSURE DEFICITS REMAIN LOW AND THERE IS F VECTOR
CONVERGENCE WITH SOME FORCING. DURING THE AFTERNOON THE COLD
CONVEYOR BELT PRECIPITATION FROM THE CLIPPER SYSTEM WILL OVERSPREAD
THE ENTIRE AREA BEFORE ENDING FROM THE WEST LATE IN THE AFTERNOON.
AS FOR AMOUNTS...A DUSTING OF ACCUMULATION IS POSSIBLE PRIOR TO
SUNRISE IN THE FAR WEST/SOUTHWEST PARTS OF THE CWFA. ACCUMULATIONS
DURING THE DAY SATURDAY SHOULD RANGE FROM A DUSTING TO ONE HALF
INCH. IT IS CONCEIVABLE THAT ACCUMULATIONS APPROACHING AN INCH MAY
OCCUR OVER THE SOUTHWEST THIRD TO HALF OF THE CWFA. ..08..
LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
ACTIVE/UNSETTLED PATTERN TO PERSIST THROUGH THE PERIOD WITH MANY FCST
CHALLENGES. MAIN STORM SYSTEM THAT BEARS CONSIDERABLE WATCHING IS IN
MON-TUE TIME-FRAME. THIS STORM LOOKS TO BRING WINTRY MIX OF PCPN WITH
POTENTIAL FOR HEADLINES.
SAT NGT... SOME RESIDUAL WEAK LIFT LINGERS INTO THE EVE ACROSS THE NORTH
AS CLIPPER DEPARTS AND WARM FRONT PUSHES THROUGH. NAM AND GFS
BUFR SOUNDINGS SHOW LOSS OF ICE INTRODUCTION WHICH WOULD SUPPORT DRIZZLE
OR FREEZING DRIZZLE. CONCERNS THOUGH THESE MODELS MAY BE OVERDONE WITH
EXTENT OF LOW LEVEL MOISTURE ... A TYPICAL BIAS ESPECIALLY WITH
NAM... ESPECIALLY GIVEN NO SNOW MELT. GIVEN UNCERTAINTIES AND WITH
ANY PCPN JUST TRACE AMOUNTS HAVE LEFT OUT ANY MENTION ATTIM. MAY SEE
TEMPS STEADY OR RISING OVRNGT ESPECIALLY SOUTH WITH ONSET OF LOW LEVEL
WARM ADVECTION.
SUN-SUN NGT... NEXT ARCTIC FRONT TO EMERGE INTO THE PLAINS AND EXPECTED
TO PUSH THROUGH IA AND POSSIBLY BISECTING 12Z MON PER NAM/GFS. HI-RES
ECMWF SLOWER BUT 12Z RUN IS SLIGHTLY FASTER AND MAY BE TRENDING TOWARD
NAM/GFS. DEEPER MOISTURE RETURNS LATE FOR POSSIBLY SOME VERY LIGHT RAIN
OR DRIZZLE AFTER MIDNIGHT... OR VERY LIGHT FREEZING RAIN/DRIZZLE IN SOME
AREAS DEPENDING ON SFC TEMPS WITH NW CWA MOST SUSCEPTIBLE IT APPEARS
ATTIM BUT THIS DEPENDENT ON FRONTAL TIMING. MOST IF NOT ALL OF
AREA SHOULD GET ABOVE FREEZING WITH 40S WIDESPREAD ACROSS THE SW CWA ON
GUSTY SOUTHERLY WINDS.
MON-TUE... STRONG BAROCLINICITY AND COUPLED JET STRUCTURE SUPPORT
CYCLOGENESIS ALONG ARCTIC FRONT... WITH CONSIDERABLE MODEL SPREAD ON
MAGNITUDE/TRACK/TIMING... AND GIVEN HIGHLY DYNAMICAL ENVIRONMENT EXPECT
CONTINUED CHANGES IN MODELS NEXT DAY OR TWO. GFS AND HI-RES ECMWF HAVE
TRENDED DEEPER AND SLOWER... AND MAY CONTINUE TO SEE THIS TREND. BOTTOM
LINE IS MOISTURE AND FORCING SUPPORTS MODERATE QPF EVENT NOT TOO
DISSIMILAR FROM THIS MOST RECENT EVENT. DEPENDING ON FRONT AND SFC LOW
LOCATIONS PCPN TYPES COULD VARY OR TRANSITION FROM RAIN TO FREEZING
RAIN...SLEET AND SNOW ACROSS CWA. THEREFORE... WITH THE WINTRY MIXTURE
THIS SYSTEM WILL BEAR CONSIDERABLE WATCHING IN THE DAYS AHEAD. POPS ARE
IN MOD/HIGH CHC CATEGORY FOR NOW GIVEN UNCERTAINTY WITH TRACK. IN
ADDITION MAY SEE FOG MON WITH AREAS OF DENSE FOG AHEAD OF SFC LOW WITHIN
LOW LEVEL MOISTURE CONVERGENCE.
WED-FRI... MUCH COLDER WITH ANOTHER ARCTIC FRONT SUGGESTED TO ARRIVE
WED THAT MAY NEED POPS IN LATER FCSTS. FOR NOW THOUGH HAVE CHC POPS
THU-FRI AS ENERGY RIPPLES ALONG LOW-MID LEVEL BAROCLINIC ZONE. WINTER HAS
FINALLY ARRIVED. ..05..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1145 AM CST SAT JAN 14 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE (TODAY AND SUNDAY)...
09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD
UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A
STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN
THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL
PLAINS. WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH
EMBEDDED WITHIN THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT
EXPECT TO SEE MANY EFFECTS FROM THIS WAVE SHORT OF SOME PASSING
LOW TO MID CLOUDS EARLY THIS MORNING. BY MID MORNING TO EARLY
AFTERNOON THE WAVE WILL MOVE THROUGH THE AREA AND SUBSIDENCE WILL
TAKE OVER BRINGING MOSTLY CLEAR CONDITIONS. AT THE SURFACE A
FAIRLY STRONG RIDGE HAS SET UP IN THE WESTERN HIGH PLAINS AND HAS
CREATED A DECENT PRESSURE GRADIENT BETWEEN ITSELF AND A WEAK
SURFACE TROUGH WHICH IS CURRENTLY LOCATED IN FAR SE NEBRASKA. AS A
RESULT OF THE GRADIENT BETWEEN THESE TWO FEATURES EXPECT WEST-
NORTHWEST WINDS TO PICK UP IN INTENSITY THROUGHOUT THE DAY
LENDING TO SOME WEAK COLD AIR ADVECTION. HOWEVER WITH LOWS
STARTING OUT A BIT WARMER THAN YESTERDAY AND WITH GOOD INSOLATION
EXPECT TEMPS TO CREEP INTO THE UPPER 40S AND LOWER 50S ACROSS
NORTHEAST KANSAS FOR TODAY. BUMPED MIN TEMPS FOR SUNDAY UPWARD A
LITTLE AS WINDS BACK AROUND TO THE WEST-SOUTHWEST OVERNIGHT AND
PICK UP EARLY SUNDAY MORNING...CREATING SOME WEAK WARM AIR
ADVECTION AND KEEPING TEMPS A BIT WARMER. SUNDAY WILL LIKELY BE
THE NICEST DAY OF THE FORECAST PERIOD...AS STRONG SOUTHERLY WINDS
AND A FLEETING UPPER RIDGE PUSHES THROUGH THE AREA. GIVEN THOSE
TWO FACTORS AS WELL AS GOOD INSOLATION DUE TO CLEAR SKIES EXPECT
TEMPS TO REACH INTO THE LOWER 60S ON SUNDAY.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)...
THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES
INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS
AHEAD OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE
COULD HAVE ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS
ON MONDAY COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD
FRONT TO BE SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY
MEANING AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY ONLY
RISE INTO THE 40S ON MONDAY. A QUICKLY MOVING UPPER WAVE WILL
ALSO PUSH THROUGH THE NORTHERN PLAINS ON MONDAY NIGHT...AND
PERHAPS COULD BRING A PERIOD OF VERY LIGHT SNOW TO AREAS NORTH OF
HIGHWAY 24 ON MONDAY NIGHT. WITH NOT MUCH MOISTURE TO WORK WITH
DO NOT EXPECT MORE THAN A TENTH OR TWO OF SNOW ACCUMULATION FROM
THIS SYSTEM. TUESDAY WILL BE RATHER CHILLY AS THE ARCTIC AIRMASS
TAKES HOLD OF THE AREA...BUT BY WEDNESDAY WEST-SOUTHWEST WINDS
WILL RETURN TO THE AREA BRINGING ANOTHER GENTLE WARM UP. MODELS
THEN HINT AT FRIDAY BEING ANOTHER UNSEASONABLY WARM DAY. SOUTH-
SOUTHWEST WINDS WITH A VERY WARM AIRMASS LOOK TO MAKE THEIR WAY
INTO NORTHEAST KANSAS ON FRIDAY. WILL CURRENTLY STICK WITH TEMPS
IN THE UPPER 40S TO LOWER 50S FOR FRIDAY...BUT IF MODELS CONTINUE
TO TREND TOWARD A WARMER SOLUTION WILL BUMP THOSE TEMPS UP AS
THAT DAY APPROACHES.
JL
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
.AVIATION...
VFR CONDITIONS EXPECTED FOR THE NEXT 24 HRS. WINDS WILL REMAIN
GUSTY UNTIL 20-21Z. WINDS WILL BECOME WESTERLY AND SOUTHWESTERLY
LATER THIS AFTERNOON AND OVERNIGHT AS SURFACE HIGH PRESSURE MOVES
TO THE SOUTHEAST. PRESSURE GRADIENT TIGHTENS AGAIN TOMORROW AND
SOUTHERLY WINDS WILL BECOME GUSTY AFTER 15Z.
ANDERSON
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
522 AM CST SAT JAN 14 2012
...UPDATE TO AVIATION...
&&
.AVIATION...
VFR ANTICIPATED THROUGH THE PERIOD. WINDOW OF GUSTY WINDS
NORTHWEST BEGINS AROUND TAF ISSUANCE AND CONTINUES INTO THE EARLY
AFTERNOON HOURS. CIGS NEAR 3KFT AGL EXPECTED TO BE SLIGHTLY HIGHER
AND NOT A SOLID DECK AS THEY MOVE OVER TOP/FOE/MHK BUT WILL
MONITOR FOR UPDATES. WINDS DROP BLO 12KTS 20-21Z THEN BECOME
WESTERLY TO SOUTHWESTERLY THIS EVENING AND OVERNIGHT. 67
&&
.PREV DISCUSSION...
/ISSUED 331 AM CST SAT JAN 14 2012/
SHORT RANGE (TODAY AND SUNDAY)...
09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD
UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A
STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN
THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL
PLAINS. WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH
EMBEDDED WITHIN THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT
EXPECT TO SEE MANY EFFECTS FROM THIS WAVE SHORT OF SOME PASSING
LOW TO MID CLOUDS EARLY THIS MORNING. BY MID MORNING TO EARLY
AFTERNOON THE WAVE WILL MOVE THROUGH THE AREA AND SUBSIDENCE WILL
TAKE OVER BRINGING MOSTLY CLEAR CONDITIONS. AT THE SURFACE A
FAIRLY STRONG RIDGE HAS SET UP IN THE WESTERN HIGH PLAINS AND HAS
CREATED A DECENT PRESSURE GRADIENT BETWEEN ITSELF AND A WEAK
SURFACE TROUGH WHICH IS CURRENTLY LOCATED IN FAR SE NEBRASKA. AS A
RESULT OF THE GRADIENT BETWEEN THESE TWO FEATURES EXPECT WEST-
NORTHWEST WINDS TO PICK UP IN INTENSITY THROUGHOUT THE DAY
LENDING TO SOME WEAK COLD AIR ADVECTION. HOWEVER WITH LOWS
STARTING OUT A BIT WARMER THAN YESTERDAY AND WITH GOOD INSOLATION
EXPECT TEMPS TO CREEP INTO THE UPPER 40S AND LOWER 50S ACROSS
NORTHEAST KANSAS FOR TODAY. BUMPED MIN TEMPS FOR SUNDAY UPWARD A
LITTLE AS WINDS BACK AROUND TO THE WEST-SOUTHWEST OVERNIGHT AND
PICK UP EARLY SUNDAY MORNING...CREATING SOME WEAK WARM AIR
ADVECTION AND KEEPING TEMPS A BIT WARMER. SUNDAY WILL LIKELY BE
THE NICEST DAY OF THE FORECAST PERIOD...AS STRONG SOUTHERLY WINDS
AND A FLEETING UPPER RIDGE PUSHES THROUGH THE AREA. GIVEN THOSE
TWO FACTORS AS WELL AS GOOD INSOLATION DUE TO CLEAR SKIES EXPECT
TEMPS TO REACH INTO THE LOWER 60S ON SUNDAY.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)...
THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES
INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS
AHEAD OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE
COULD HAVE ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS
ON MONDAY COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD
FRONT TO BE SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY
MEANING AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY ONLY
RISE INTO THE 40S ON MONDAY. A QUICKLY MOVING UPPER WAVE WILL
ALSO PUSH THROUGH THE NORTHERN PLAINS ON MONDAY NIGHT...AND
PERHAPS COULD BRING A PERIOD OF VERY LIGHT SNOW TO AREAS NORTH OF
HIGHWAY 24 ON MONDAY NIGHT. WITH NOT MUCH MOISTURE TO WORK WITH
DO NOT EXPECT MORE THAN A TENTH OR TWO OF SNOW ACCUMULATION FROM
THIS SYSTEM. TUESDAY WILL BE RATHER CHILLY AS THE ARCTIC AIRMASS
TAKES HOLD OF THE AREA...BUT BY WEDNESDAY WEST-SOUTHWEST WINDS
WILL RETURN TO THE AREA BRINGING ANOTHER GENTLE WARM UP. MODELS
THEN HINT AT FRIDAY BEING ANOTHER UNSEASONABLY WARM DAY. SOUTH-
SOUTHWEST WINDS WITH A VERY WARM AIRMASS LOOK TO MAKE THEIR WAY
INTO NORTHEAST KANSAS ON FRIDAY. WILL CURRENTLY STICK WITH TEMPS
IN THE UPPER 40S TO LOWER 50S FOR FRIDAY...BUT IF MODELS CONTINUE
TO TREND TOWARD A WARMER SOLUTION WILL BUMP THOSE TEMPS UP AS
THAT DAY APPROACHES.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
331 AM CST SAT JAN 14 2012
.DISCUSSION...
SHORT RANGE (TODAY AND SUNDAY)...
09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD
UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A
STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN
THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL PLAINS.
WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH EMBEDDED WITHIN
THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT EXPECT TO SEE MANY
EFFECTS FROM THIS WAVE SHORT OF SOME PASSING LOW TO MID CLOUDS
EARLY THIS MORNING. BY MID MORNING TO EARLY AFTERNOON THE WAVE WILL MOVE
THROUGH THE AREA AND SUBSIDENCE WILL TAKE OVER BRINGING MOSTLY CLEAR
CONDITIONS. AT THE SURFACE A FAIRLY STRONG RIDGE HAS SET UP IN THE
WESTERN HIGH PLAINS AND HAS CREATED A DECENT PRESSURE GRADIENT
BETWEEN ITSELF AND A WEAK SURFACE TROUGH WHICH IS CURRENTLY
LOCATED IN FAR SE NEBRASKA. AS A RESULT OF THE GRADIENT BETWEEN
THESE TWO FEATURES EXPECT WEST-NORTHWEST WINDS TO PICK UP IN
INTENSITY THROUGHOUT THE DAY LENDING TO SOME WEAK COLD AIR
ADVECTION. HOWEVER WITH LOWS STARTING OUT A BIT WARMER THAN
YESTERDAY AND WITH GOOD INSOLATION EXPECT TEMPS TO CREEP INTO THE
UPPER 40S AND LOWER 50S ACROSS NORTHEAST KANSAS FOR TODAY. BUMPED
MIN TEMPS FOR SUNDAY UPWARD A LITTLE AS WINDS BACK AROUND TO THE
WEST-SOUTHWEST OVERNIGHT AND PICK UP EARLY SUNDAY
MORNING...CREATING SOME WEAK WARM AIR ADVECTION AND KEEPING TEMPS
A BIT WARMER. SUNDAY WILL LIKELY BE THE NICEST DAY OF THE FORECAST
PERIOD...AS STRONG SOUTHERLY WINDS AND A FLEETING UPPER RIDGE
PUSHES THROUGH THE AREA. GIVEN THOSE TWO FACTORS AS WELL AS GOOD
INSOLATION DUE TO CLEAR SKIES EXPECT TEMPS TO REACH INTO THE LOWER
60S ON SUNDAY.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)...
THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES
INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS AHEAD
OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE COULD HAVE
ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS ON MONDAY
COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD FRONT TO BE
SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY MEANING AREAS NORTH
AND WEST OF THE TURNPIKE WILL LIKELY ONLY RISE INTO THE 40S ON
MONDAY. A QUICKLY MOVING UPPER WAVE WILL ALSO PUSH THROUGH THE
NORTHERN PLAINS ON MONDAY NIGHT...AND PERHAPS COULD BRING A PERIOD
OF VERY LIGHT SNOW TO AREAS NORTH OF HIGHWAY 24 ON MONDAY NIGHT.
WITH NOT MUCH MOISTURE TO WORK WITH DO NOT EXPECT MORE THAN A TENTH
OR TWO OF SNOW ACCUMULATION FROM THIS SYSTEM. TUESDAY WILL BE
RATHER CHILLY AS THE ARCTIC AIRMASS TAKES HOLD OF THE AREA...BUT BY
WEDNESDAY WEST-SOUTHWEST WINDS WILL RETURN TO THE AREA BRINGING
ANOTHER GENTLE WARM UP. MODELS THEN HINT AT FRIDAY BEING ANOTHER
UNSEASONABLY WARM DAY. SOUTH-SOUTHWEST WINDS WITH A VERY WARM
AIRMASS LOOK TO MAKE THEIR WAY INTO NORTHEAST KANSAS ON FRIDAY.
WILL CURRENTLY STICK WITH TEMPS IN THE UPPER 40S TO LOWER 50S FOR
FRIDAY...BUT IF MODELS CONTINUE TO TREND TOWARD A WARMER SOLUTION
WILL BUMP THOSE TEMPS UP AS THAT DAY APPROACHES.
JL
&&
.AVIATION...
WIND FORECAST REMAINS THE BIGGEST CHALLENGE WITH VFR CONDITIONS
STILL EXPECTED. LOW PRESSURE TO MOVE SOUTHEAST THROUGH EASTERN
NEBRASKA AND NORTHERN MISSOURI THROUGH 15Z WITH WINDS SHIFTING AS
A RESULT. BACKED OFF THE NORTHWEST WIND TIMING A BIT WITH MIXING
INTO THE DEEPER WINDS HOLDING OFF A BIT. WINDS COME BACK TO LIGHT
SOUTHERLY IN THE 20Z-03Z PERIOD.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1022 PM MST FRI JAN 13 2012
.UPDATE...
646 PM MST FRI JAN 13 2012
LATEST RUC AND HRRR CATCHING INCOMING SURFACE TROUGH FROM THE
NORTHWEST. THEY HAD THE STRENGTH/POSITION THE BEST WITH THE
REMAINING MODEL OUTPUT NOT STRONG ENOUGH. SO INCREASED WIND SPEEDS
OVER THE NORTHEAST PORTION OF THE AREA A LITTLE. ALSO BECAUSE OF
THE STRONGER WINDS RAISED THE MINS SOME THAT SAME AREA AS WELL.
OTHERWISE...JUST ADJUSTED HOURLY GRIDS.
BULLER
&&
.DISCUSSION...
208 PM MST FRI JAN 13 2012
TONIGHT...SHOULD SEE NORTHWEST WINDS OF 10 TO 20 MPH WINDS WITH
HIGHER GUSTS THROUGH MIDNIGHT BEHIND A DEPARTING UPPER LEVEL
DISTURBANCE. AFTER MIDNIGHT WINDS SUBSIDE A BIT INTO THE 10 MPH
RANGE. OVERNIGHT LOWS WILL BE A BIT WARMER THEN THE PAST FEW NIGHTS
AS WARM AIR ALOFT MOVES IN. WILL AIM FOR LOWS GENERALLY IN THE UPPER
TEENS TO LOW 20S IN FAR EASTERN COLORADO...LOW TO MID 20S EAST OF
THE CO/KS BORDER. THIS IS SEVERAL DEGREES WARMER THAN THE MAV AND
MET MOS GUIDANCE.
007
SATURDAY-SUNDAY...H5 RIDGE CONTINUES TO BUILD EAST TOWARDS CWA...WITH
DRY/STABLE AIR MASS IN PLACE THROUGH SUNDAY NIGHT. TEMPERATURES
WILL CONTINUE TO MODERATE OVER THE NEXT FEW DAYS...WITH HIGH TEMPS
IN THE 50S SATURDAY...AND MID/UPPER 50S ON SUNDAY. CONSIDERING
TEMPS ALOFT SAT/SUN NIGHTS...BUMPED LOWS TO THE UPPER 20S. THIS IS
ABOUT 5-10F ABOVE MOS GUIDANCE...HOWEVER CONSIDERING TEMPS ALOFT
AND POSSIBLE SKY COVER SUN NIGHT...THIS MAY STILL BE TOO COOL.
MONDAY-MONDAY NIGHT...TROUGH DEVELOPING OVER THE PACIFIC NW OVER THE
WEEKEND WILL PROGRESS EAST ACROSS THE GREAT BASIN TOWARDS THE CWA
MONDAY. GUIDANCE STILL DIFFERS BY ABOUT 6HR ON TIMING OF ASSOCIATED
COLD FRONT MONDAY...HOWEVER OVERALL TREND HAS BEEN TO SPEED UP
ARRIVAL...WITH FRONTAL PASSAGE LIKELY BY MIDDAY. PRECIP ASSOCIATED WITH
LARGE SCALE ASCENT ALONG LEADING EDGE OF TROUGH AXIS LOOKS TO ARRIVE
FROM THE NW LATE MONDAY AFTERNOON...QUICKLY MOVING EAST THROUGH THE
EVENING HOURS. GUIDANCE IN GOOD AGREEMENT ON STABLE/DRY AIR QUICKLY
MOVING IN AFTER 06Z...SO I TRENDED FORECAST IN THAT DIRECTION. I
KEPT BEST CHANCES DURING THE EVENING IN THE NORTH...AND LEFT A SMALL
AREA OF SLIGHT CHANCE POPS IN THE FAR EAST AFTER 06Z. CONSIDERING
LIMITED MOISTURE AND QUICK NATURE OF THIS SYSTEM...ONLY ANTICIPATING
LIGHT SNOW ACCUMULATIONS...ABOUT AN INCH OR LESS.
TUESDAY-FRIDAY...REMAINING FORECAST LOOKS DRY WITH W/NW FLOW
DEVELOPING ACROSS WESTERN CONUS...AND DRY/STABLE AIR MASS IN PLACE.
BIGGEST QUESTION THROUGH THESE PERIODS WILL BE HOW QUICKLY SHALLOW
COLD AIR MASS MODERATES...AND WHAT TEMPS WILL DO IN RESPONSE TO WEAK
SHORTWAVE TROUGHS EMBEDDED WITHIN MEAN FLOW. FOR NOW EXPECT BELOW
NORMAL TEMPS TUESDAY AND NEAR NORMAL TEMPS WEDNESDAY. GUIDANCE STILL
INDICATING RISING H5 HEIGHTS H85 TEMPS TO ABOUT 10-12C BY
FRIDAY...WHEN I KEPT FORECAST OF MID 50S IN THE WEST. THIS MAY END
UP BEING TOO COOL CONSIDERING CONDITIONS ALOFT...HOWEVER THERE IS
ENOUGH UNCERTAINTY IN REGARDS TO BOUNDARY LAYER DIFFERENCES TO
KEEP ME FROM CHANGING TOO MUCH THIS FAR OUT.
DR
&&
.AVIATION...
1020 PM MST FRI JAN 13 2012
FOR THE 06Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
SURFACE TROUGH WILL MOVE THROUGH THE AREA TONIGHT AND CAUSE SOME
GUSTY WINDS...MAINLY AT KMCK. AFTER THAT...WINDS WILL GRADUALLY
SHIFT THROUGH THE PERIOD AS THE SURFACE RIDGE MOVES EAST AND THE
LEE TROUGH DEVELOPS.
BULLER
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
800 AM EST SAT JAN 14 2012
.SYNOPSIS...
COLD UPPER LEVEL LOW PRESSURE, PASSING SLOWLY EASTWARD THROUGH THE
GREAT LAKES, WILL MAINTAIN COLD CONDITIONS AND LIGHT SNOW SHOWERS
TODAY. MIDWEST HIGH PRESSURE WILL PROVIDE A DRY SUNDAY AND EARLY
MONDAY. CANADIAN LOW PRESSURE WILL FIRST BRING A WARM UP WITH RAIN
SHOWERS LATE MONDAY AND TUESDAY, FOLLOWED BY A COOL DOWN WITH SNOW
SHOWERS TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FOR MINOR ADJUSTMENTS TO POPS. RECENT SATELLITE DATA
SHOWS CLOUD TOPS WARMING AND LIKEWISE RECENT RADAR AND SURFACE
DATA SHOW SNOW FALL RATES HAVE DECREASED. WITH HRRR AND NAM MODEL
OUTPUT SHOWING LITTLE SNOW REJUVENATION, EXPECT SLOW DECREASE THIS
MORNING, WEST TO EAST, WITH PERHAPS A DRY BREAK BY AFTERNOON. SNOW
ACCUMULATIONS WILL BE MINIMAL.
PER BLEND OF RECENT GFS AND NAM MOS, FORECASTED TEMPERATURES THIS
AFTERNOON TO CLIMB TO HIGHS THAT WILL STILL BE 7 TO 12 DEGREES
COLDER THAN NORMAL.
NAM MODEL PROFILES SHOW WINDS DECREASING TO NORMAL VALUES BY
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
RECENT SREF MODEL OUTPUT SHOWS ONE MORE UPPER LEVEL TROUGH PASSING
THROUGH THE UPPER OHIO VALLEY THIS EVENING. EXPECT MAINLY ISOLATED
SNOW SHOWERS ACROSS THE MOUNTAINS WITH NO MORE THAN FLURRIES
ELSEWHERE.
AS UPPER TROUGH EXITS EAST, MIDWEST HIGH PRESSURE ENSUES TO PROVIDE
A DRY SUNDAY.
PER BLEND OF RECENT GFS AND NAM MOS, FORECASTED TEMPERATURES TONIGHT
TO YIELD LOWS 5 TO 8 DEGREES COLDER THAN NORMAL. HIGHS SUNDAY MAY BE
SLIGHTLY WARMER THAN TODAY, BUT STILL GENERALLY ABOUT 5 TO 8 DEGREES
COLDER THAN NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
RECENT SREF MODEL OUTPUT SHOWS HIGH PRESSURE MAINTAINING DRY
CONDITIONS SUNDAY NIGHT INTO MONDAY.
BLEND OF RECENT ECMWF AND GFS MODEL OUTPUT SHOWS THE ROBUST UPPER
LEVEL JETSTREAM ACROSS NORTH AMERICA WILL THEN STEER A LOW PRESSURE
SYSTEM EASTWARD THROUGH THE GREAT LAKES AND MIDWEST MONDAY NIGHT
INTO WEDNESDAY. WEST TO SOUTHWEST WINDS AHEAD OF THE SYSTEM`S COLD
FRONT WILL PROVIDE A WARM UP MONDAY, SO THE INITIAL PRECIPITATION
TYPE SHOULD BE RAIN SHOWERS MONDAY NIGHT AND TUESDAY.
MODELS THEN SHOW A POST FRONTAL COOL DOWN WITH SNOW SHOWERS TUESDAY
NIGHT INTO POSSIBLY WEDNESDAY. ANOTHER CANADIAN COLD FRONTAL PASSAGE
MAY PROVIDE SNOW SHOWERS THURSDAY.
REGARDING TEMPERATURE DETAILS, BLEND OF RECENT GFS MOS AND NAEFS
MEDIAN VALUES SHOW THE WARM UP MONDAY INTO TUESDAY TO YIELD VALUES
10 TO 15 DEGREES WARMER THAN NORMAL. THE POST FRONTAL COOL DOWN
STARTING TUESDAY NIGHT WILL YIELD VALUES 5 TO 10 DEGREES COLDER
THAN NORMAL, THAT COULD LAST INTO FRIDAY.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY MVFR CONDITIONS INTO TONIGHT, MAINLY DUE TO
STRATOCUMULUS CEILINGS.
AS ONE UPPER LEVEL SHORT-WAVE TROUGH EXITS EAST, RECENT SATELLITE
DATA SHOWS WARMING TOPS AND SURFACE AND RADAR DATA SHOW SNOW FALL
RATES HAVE SLOWED. SO VISIBILITIES CAN BE UNRESTRICTED AT TIMES
TODAY.
A SECOND UPPER LEVEL SHORT-WAVE TROUGH CAN PASS EASTWARD THROUGH
THE UPPER OHIO VALLEY THIS EVENING. THIS MAY CAUSE SCATTERED LIGHT
SNOW SHOWERS WITH VISIBILITIES POSSIBLY RESTRICTED.
SURFACE WINDS WILL BE MAINLY WEST SOUTHWEST NEAR 10 KTS WITH GUSTS
TO 20 KTS INTO MIDDAY.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
EXPECT MAINLY VFR SUNDAY INTO MIDDAY MONDAY. NEXT CHANCE OF
RESTRICTIONS WILL BE LATE MONDAY INTO WEDNESDAY FROM MIXED
PRECIPITATION ASSOCIATED WITH A LOW PRESSURE SYSTEM PASSING EASTWARD
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
643 PM EST SUN JAN 15 2012
UPDATED AVIATION DISCUSSION FOR THE 00Z TAFS
.SHORT TERM /TONIGHT THROUGH MONDAY/... ISSUED AT 415 PM EST
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 00Z TAF ISSUANCE/...
CHALLENGING FCST IS SHAPING UP FOR THE TONIGHT PERIOD AT
KIWD/KCMX/KSAW. GUIDANCE POINTS TO STRATUS DEVELOPING UNDER
SOUTHERLY FLOW AHEAD OF LOW PRES TRACKING E INTO NRN ONTARIO. WITH
THE EXCEPTION OF AREAS WHERE WINDS HAVE AN ONSHORE COMPONENT OFF
LAKE MICHIGAN...LOW CLOUDS HAVE YET TO DEVELOP. CONDITIONS DO SEEM
FAVORABLE GIVEN HIGHER DWPTS ADVECTING N INTO COOLER AIRMASS OVER
SNOWPACK ACROSS NRN WI/UPPER MI. ALTHOUGH CONFIDENCE IS LOW...OPTED
TO GO WITH THE GUIDANCE IDEA OF MVFR CIGS DEVELOPING THIS EVENING.
CONFIDENCE IS HIGHEST AT KSAW AS UPSLOPE FLOW COMPONENT OFF LAKE
MICHIGAN DURING THE EVENING IS MOST FAVORABLE FOR A LOW
MVFR/POSSIBLE IFR CIG. LOW-LEVEL JET OF 40-50KT WILL TRANSLATE
ACROSS THE AREA THIS EVENING...BUT RIGHT NOW...IT APPEARS THERE WILL
BE SUFFICIENT MIXING/GUSTY WINDS TO THE SFC TO PRECLUDE LLWS. COLD
FRONT WILL PASS ACROSS THE AREA MON. POST FRONTAL UPSLOPE WINDS AT
KIWD/KCMX WILL BE MORE FAVORABLE FOR LOWER MVFR CIGS AT THOSE 2
SITES.
&&
.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...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
758 PM CST SUN JAN 15 2012
.UPDATE...
STRATUS NOW BEGINNING TO FORM ACROSS WI...THOUGH MUCH FURTHER EAST
THAN GUIDANCE WAS INDICATING EARLIER THIS AFTERNOON. IN
ADDITION...925 MB RH FORECASTS FROM THE RUC HAVE BEEN TRENDING THE
LOW STRATUS/FZDZ FURTHER EAST AS WELL WITH EACH SUBSEQUENT RUN. AS
A RESULT...UPDATED THE WEATHER GRID TO SHUNT FZDZ MENTION FURTHER
EAST...WITH ONLY A MENTION LEFT FOR LADYSMITH AND THE ERN SLIVERS
OF CHIP AND EAU CLAIRE COUNTIES IN WI. BEST FZDZ POTENTIAL LOOKS
TO REMAIN EAST OF THE MPX CWA AT THIS POINT...BUT WILL CONTINUE TO
MONITOR CLOSELY.
&&
.AVIATION.../00Z TAF ISSUANCE/
A LITTLE TRICKY FORECAST THIS EVENING ESPECIALLY OVER EASTERN
AREAS. INCREASING LOW LEVEL MOISTURE AHEAD OF THE FRONTAL SYSTEM...
AND OVER SNOW COVER THAT IS IN PLACE FROM EASTERN IOWA TO
WISCONSIN...WILL LIKELY CAUSE SOME IFR CIGS TO DEVELOP...MAINLY
OVER WESTERN WISCONSIN...AFTER 03-04Z. THERE IS ALSO A SMALL RISK
AT KMSP BUT HAVE ONLY INDICATED A BKN CIG FOR A FEW HOURS AFTER
08Z. WILL WATCH TRENDS THIS EVENING AND THIS CONDITION COULD BE
DROPPED IN LATER FORECASTS. THERE IS ALSO A RISK OF FREEZING
DRIZZLE AT KRNH AND KEAU. OTHERWISE...COLD FRONT WILL BE MOVING
INTO THE AREA LATE TONIGHT AND MONDAY MORNING. VFR CONDITIONS OVER
THE REST OF THE MN TAF SITES PRIOR TO THE FRONT. AREAS OF MVFR
CIGS COULD DEVELOP BEHIND THE FRONT...BUT ONLY LAST INTO EARLY
AFTERNOON. LOWER VFR CIGS WILL THEN DEVELOP TOWARD THE END OF THE
TAF PERIOD. IF EXTENSIVE IFR CIGS DEVELOP IN WISCONSIN...THEN MVFR
CIGS WOULD PERSIST THROUGH THE DAY MONDAY. SOME GUSTY NORTHWEST
WINDS BEHIND THE COLD FRONT TO AROUND 22 KNOTS.
KMSP...AS MENTIONED ABOVE..SOMEWHAT OF A TRICKY FORECAST WITH THE
CHANCE OF IFR CIGS DEVELOPING LATE TONIGHT AHEAD OF THE COLD
FRONT. BETTER CHANCE OF THIS FARTHER TO THE EAST WHERE THERE IS
SNOW COVER. IF THE DEVELOPMENT OF THE CIGS DOES NOT OCCUR...THE
THE ONLY OTHER ISSUE WOULD BE AREAS OF MVFR CIGS ABOVE 017
BEHIND THE COLD FRONT ON MONDAY. THE CHANCE OF SNOW MOVES IN
PRIOR TO 06Z TUESDAY.
OUTLOOK...06Z-12Z TUESDAY...MVFR CIGS AND IFR VSBYS.
&&
.PREV DISCUSSION...
/ISSUED 555 PM CST SUN JAN 15 2012/
ANOTHER VERY WARM DAY TODAY ACROSS THOSE PARTS OF THE AREA THAT
DON`T HAVE SNOW ON THE GROUND WHERE LOWER AND MID 40S APPEARED.
SNOW COVER ACROSS WC WI HELD TEMPS BACK IN THE MID 30S. BREEZY SOUTH
WINDS AHEAD OF CDFNT PLOWING ACROSS THE DKTS HAS PUSHED TEMPS TO
AROUND 50 NEAR THE IA BORDER IN SW MN.
CONCERN FOR THE OVERNIGHT IS WITH STRATUS TO FORM AHEAD OF CDFNT
MAINLY OVER THE SNOWPACK IN WI. SREF PROB CIGS AOA 1000 FT
CONTINUES WITH RAPID BLOSSOMING OF CLDS BY 06Z ACROSS THAT AREA. NAM
CONTINUES TO KNOCK OUT .01 QPF. PROGGED SOUNDSINGS SHOW THAT
FAVORED PCPN TYPE WOULD BE -FZDZ WITH ELEVATED WARM LAYER AND NO ICE
CRYSTAL FEEDERS FROM ABOVE.
TEMPS IN WAKE OF COLD FRONT CRASH QUICKLY WITH A FAIRLY COLD AIRMASS
BUILDING IN BEHIND. CURRENT TEMPS IN THE PRAIRIE OF SACK ONLY IN
THE SINGLE DIGITS ALMOST TO THE NODAK BORDER. MODELS CONTINUE TO
HAVE SOME ISSUES WITH -SN FOR LATER MONDAY INTO TUESDAY...BUT THE
GENERAL TREND IS FOR A BIT SLOWER PROGRESSION OF PCPN ACROSS AREA
AS THE TROF NOW MOVING INTO THE PACIFIC NW MOVES THRU AREA.
CONTINUED WITH LIKELY POPS...BUT FAIRLY LOW QPF AS UPPER TROF
FEEDS ONLY ON COLD ADVECTION AS IT PROGRESSES THRU AREA. SHUD SEE
FAIRLY WDSPD SNOW IN THE HALF INCH TO PERHAPS ONE INCH
RANGE...MAYBE A LITTLE MORE IN SC. ALSO HELD ONTO -SN THRU TUESDAY
MORNING SE CWA WITH GFS/EC/NAM AND SREF ALL CONTINUING TO SPIT OUT
LGT PCPN.
FAST MOVING ZONAL FLOW BRINGS ANOTHER WAVE THRU ON WEDNESDAY AND
ANOTHER ON FRIDAY. WITH BAROCLINIC ZONE REMAINING ACROSS AREA THEY
SHUD BE ABLE TO WRING OUT SOME -SN. PLACEMENT WILL BE AN ISSUE WITH
GFS KEYING MORE ONTO BRINGING WED -SN MORE ACROSS CENTRAL CWA WITH
OTHER MODEL SOLUTIONS A BIT FARTHER NORTH. TEMPERATURES WILL ALSO
BE A CHALLENGE WITH THE PUSH-PULL OF ISOTHERMS ACROSS AREA AS
SYSTEMS MIGRATE THRU. COLDEST MORNING OF THE PERIOD WILL PROBABLY BE
THURSDAY WHEN HIGH PRESSURE BUILDS IN...BUT COLD WON`T LAST AS NEXT
PUSH OF VERY WARM AIR SURGES NORTH INTO THE AREA OVER THE WEEKEND.
$$
MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
$$
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
127 AM CST SAT JAN 14 2012
.DISCUSSION...
HAVE UPDATED FORECAST THIS MORNING FOR PRECIP TRENDS AS WELL AS
TEMPERATURES. SHORTWAVE DIVING OUT OF THE DAKOTAS INTO CENTRAL NEB
IS INDUCING FLURRIES OR LIGHT SNOW IN SOUTHEAST SD TO
NORTHWEST/CENTRAL IA. NORTHWESTERLY FETCH OF AREAS OF SNOW HAS
BEEN SKIRTING THE FRINGE OF THE CWA...AND OBS HAVE INDICATED NO
VIS REDUCTIONS WITHIN THE CWA...WITH YKN AND DNS THE CLOSEST
LOCATIONS RECEIVING ENOUGH LIGHT SNOW TO LOWER VIS. HAVE PULLED
DOWN POPS SIGNIFICANTLY AWAY FROM THE NORTHERN AND EASTERN MARGINS
OF THE CWA THIS MORNING...WITH JUST FLURRIES AFTER 09Z. ALSO
TWEAKED TEMPERATURE CURVE THROUGH THE MORNING HOURS AS
TEMPERATURES ARE BEGINNING TO RISE IN THE WESTERN CWA ON THE NOSE
OF HIGHER WESTERLY WINDS.
MAYES
&&
.PREV DISCUSSION... /ISSUED 1124 PM CST FRI JAN 13 2012/
AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
SURFACE LOW WAS DEEPENING/ORGANIZING JUST SW OF KOFK AT 14/05Z.
THIS LOW SHOULD TRACK SW OF KOMA AND INTO NW MO BY 12Z THEN
QUICKLY INTO SE MO BY SATURDAY AFTERNOON. LOW WILL SPREAD GUSTY NW
SURFACE WINDS TO TAF SITES BY MORNING...ALTHOUGH STRONGEST COULD
REMAIN JUST TO THE WEST. LOW CLOUDS AND LIGHT SNOW E THROUGH NE OF
LOW AT 14/04Z SHOULD STAY MOSTLY NE OF TAF SITES UNTIL AFTER LOW
PASSES TO THE SOUTH THEN A PERIOD OF MVFR CIGS ALONG WITH SNOW WAS
FORECAST AT KOFK AND KOMA WITH JUST THE LOW CLOUD MENTION AT
KLNK. CONFIDENCE IN SNOW REACHING TAF SITES WAS NOT HIGH. LOW
LEVEL DRY AIR WAS A NEGATIVE AND SNOW WAS HAVING A HARD TIME
WORKING S INTO NERN NEBRASKA BEFORE TAF ISSUANCE. OTHERWISE SKIES
SHOULD CLEAR BY LATE MORNING/EARLY AFTERNOON AND WINDS WILL BEGIN
DECREASING LATER IN THE AFTERNOON BEFORE TURNING S/SW AHEAD OF
ANOTHER SYSTEM BEGINNING TO DROP INTO SRN CANADA.
CHERMOK
PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/
SHORT TERM...TONIGHT THROUGH MONDAY.
THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST
TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY
SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL
THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW
MOVING IN FROM THE WEST MONDAY.
AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY
20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS
WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY
ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS
IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY
12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND
POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT
FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION
MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND
THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING
LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH
THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE
STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING...
SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO
CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT
THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST.
ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE
ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT
INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE
AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY
TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA.
MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER
TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE
NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND
SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL
RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND
WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE
IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END.
ZAPOTOCNY
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD
AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL
GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF
THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS
WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY
HIGHS RANGED FROM 21 TO 49 AT OMAHA.
LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER
FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER
THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA
AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT
SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO
NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST
MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER
ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY
AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING.
THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW
THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL
ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY.
THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW
STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS
BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD
EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING
BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS
6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST.
ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE
ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT
FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL
HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH
HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE
WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE
SOME LIGHT SNOW WITH THIS SCENARIO.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1124 PM CST FRI JAN 13 2012
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
SURFACE LOW WAS DEEPENING/ORGANIZING JUST SW OF KOFK AT 14/05Z.
THIS LOW SHOULD TRACK SW OF KOMA AND INTO NW MO BY 12Z THEN
QUICKLY INTO SE MO BY SATURDAY AFTERNOON. LOW WILL SPREAD GUSTY NW
SURFACE WINDS TO TAF SITES BY MORNING...ALTHOUGH STRONGEST COULD
REMAIN JUST TO THE WEST. LOW CLOUDS AND LIGHT SNOW E THROUGH NE OF
LOW AT 14/04Z SHOULD STAY MOSTLY NE OF TAF SITES UNTIL AFTER LOW
PASSES TO THE SOUTH THEN A PERIOD OF MVFR CIGS ALONG WITH SNOW WAS
FORECAST AT KOFK AND KOMA WITH JUST THE LOW CLOUD MENTION AT
KLNK. CONFIDENCE IN SNOW REACHING TAF SITES WAS NOT HIGH. LOW
LEVEL DRY AIR WAS A NEGATIVE AND SNOW WAS HAVING A HARD TIME
WORKING S INTO NERN NEBRASKA BEFORE TAF ISSUANCE. OTHERWISE SKIES
SHOULD CLEAR BY LATE MORNING/EARLY AFTERNOON AND WINDS WILL BEGIN
DECREASING LATER IN THE AFTERNOON BEFORE TURNING S/SW AHEAD OF
ANOTHER SYSTEM BEGINNING TO DROP INTO SRN CANADA.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 521 PM CST FRI JAN 13 2012/
AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK.
CLIPPER-TYPE SYSTEM SHOULD MOVE QUICKLY INTO NERN NEBRASKA AROUND
14/06Z AND THEN INTO SERN MO BY 14/18Z. THIS SYSTEM WILL BRING A
SHIFT TO GUSTY NORTHWEST WINDS LATE TONIGHT/EARLY SATURDAY...
AND POSSIBLY A PERIOD OF LOWER CLOUDS AND SCATTERED SNOW SHOWERS.
SNOW CHCS APPEARED SOMEWHAT BETTER AT KOFK AND KOMA. SURFACE WINDS
SHOULD RELAX SATURDAY AFTERNOON BEFORE TURNING TO S/SW IN THE
EVENING AHEAD OF YET ANOTHER SYSTEM.
CHERMOK
PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/
SHORT TERM...TONIGHT THROUGH MONDAY.
THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST
TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY
SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL
THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW
MOVING IN FROM THE WEST MONDAY.
AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY
20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS
WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY
ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS
IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY
12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND
POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT
FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION
MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND
THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING
LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH
THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE
STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING...
SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO
CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT
THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST.
ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE
ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT
INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE
AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY
TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA.
MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER
TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE
NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND
SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL
RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND
WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE
IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END.
ZAPOTOCNY
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD
AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL
GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF
THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS
WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY
HIGHS RANGED FROM 21 TO 49 AT OMAHA.
LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER
FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER
THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA
AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT
SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO
NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST
MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER
ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY
AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING.
THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW
THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL
ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY.
THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW
STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS
BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD
EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING
BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS
6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST.
ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE
ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT
FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL
HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH
HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE
WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE
SOME LIGHT SNOW WITH THIS SCENARIO.
DERGAN
AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL SITES THROUGH THE
TAF PERIOD. A FRONTAL BOUNDARY WILL APPROACH THE CWA THIS
AFTERNOON...BRINGING WINDS AROUND TO THE SOUTHEAST AHEAD OF THE
FRONT. OVERNIGHT...WINDS BEHIND THE FRONT ARE EXPECTED TO
INCREASE AND SWITCH TO THE NORTHWEST.
ROUKE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
210 PM CST SAT JAN 14 2012
.DISCUSSION...
NEED TO DO A QUICK UPDATE FOR TEMPS THIS AFTN AS TEMPS RISING WELL
INTO THE MID 30S IN FAR SE ND... THIS IS HIGHER THAN PREV UDPATE....
&&
.PREV DISCUSSION... /ISSUED 1002 AM CST SAT JAN 14 2012/
DISCUSSION...
MINOR UPDATE TO WINDS AND PRECIP WERE MADE. BASED ON SFC WIND
FIELD WK SFC LOW JUST WEST OF WINNIPEG...WITH WEST WIND SHIFT
THROUGH WALHALLA-CAVALIER THEN TO GRAND FORKS AIR FORCE BASE (AS
OF 1543Z) THEN TO JUST WEST OF FARGO-WAHPETON TO WHEATON. SFC LOW
WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TOWARD BAUDETTE BY 21Z-00Z
AND WITH IT WIND WILL GRADUALLY SHIFT TO THE WEST AS BOUNDARY
MOVES THROUGH. WARMER AIR BEHIND IT WITH TEMPS IN THE MID 20S. FAR
NORTHEAST MAY NEVER QUITE GET INTO THE 20S SO LOWERED A BIT
THERE...OTHERWISE ADJUSTED CURVE A BIT BUT KEPT HIGHS IN THE MID
20S FOR THE MOST PART...WITH SOME READINGS NEAR 30 IN FAR
SOUTHWEST FCST AREA WHERE SOME SUNNY BREAKS WILL OCCUR. OTHERWISE
SATELLITE SHOWS PLENTY OF CLOUDS MOVING SOUTHEAST SO EXPECT
MAJORITY OF THE FCST AREA TO REMAIN IN THE CLOUDS. KEPT FLURRIES
OR LIGHT SNOW IN FOR NORTHEAST 1/2 OF FCST AREA THRU THE DAY AS
UPSTREAM CANADIAN RADAR SHOWS LIGHT ECHOES UP TO DAUPHIN MANITOBA.
,AVIATION...
CIGS WILL REMAIN MOSLY VFR FAR-GFK-DVL THRU THE DAY. TVF-BJI WILL
SEE MVFR CIGS GRADUALLY BECOME VFR IN LIGHT SNOW.
PREV DISCUSSION... /ISSUED 230 AM CST SAT JAN 14 2012/
DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES
TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR
DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL
USE BLEND.
BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND
WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON
CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND
THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER
OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS
BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE
LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES
FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST
AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE
BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION
LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY.
FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN
THE 20S.
TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY
MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND
WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN
CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE.
NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN
BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF
FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG
WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY
OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS
COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED
32 DEGREES.
STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT
INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE
BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS
FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY
TO RECOVER AT ALL MONDAY AND MAY EVEN DROP.
LONG TERM (TUE-FRI)...
MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC
AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO
NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT
SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK
FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1002 AM CST SAT JAN 14 2012
.DISCUSSION...
MINOR UPDATE TO WINDS AND PRECIP WERE MADE. BASED ON SFC WIND
FIELD WK SFC LOW JUST WEST OF WINNIPEG...WITH WEST WIND SHIFT
THROUGH WALHALLA-CAVALIER THEN TO GRAND FORKS AIR FORCE BASE (AS
OF 1543Z) THEN TO JUST WEST OF FARGO-WAHPETON TO WHEATON. SFC LOW
WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TOWARD BAUDETTE BY 21Z-00Z
AND WITH IT WIND WILL GRADUALLY SHIFT TO THE WEST AS BOUNDARY
MOVES THROUGH. WARMER AIR BEHIND IT WITH TEMPS IN THE MID 20S. FAR
NORTHEAST MAY NEVER QUITE GET INTO THE 20S SO LOWERED A BIT
THERE...OTHERWISE ADJUSTED CURVE A BIT BUT KEPT HIGHS IN THE MID
20S FOR THE MOST PART...WITH SOME READINGS NEAR 30 IN FAR
SOUTHWEST FCST AREA WHERE SOME SUNNY BREAKS WILL OCCUR. OTHERWISE
SATELLITE SHOWS PLENTY OF CLOUDS MOVING SOUTHEAST SO EXPECT
MAJORITY OF THE FCST AREA TO REMAIN IN THE CLOUDS. KEPT FLURRIES
OR LIGHT SNOW IN FOR NORTHEAST 1/2 OF FCST AREA THRU THE DAY AS
UPSTREAM CANADIAN RADAR SHOWS LIGHT ECHOES UP TO DAUPHIN MANITOBA.
&&
,AVIATION...
CIGS WILL REMAIN MOSLY VFR FAR-GFK-DVL THRU THE DAY. TVF-BJI WILL
SEE MVFR CIGS GRADUALLY BECOME VFR IN LIGHT SNOW.
&&
.PREV DISCUSSION... /ISSUED 230 AM CST SAT JAN 14 2012/
DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES
TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR
DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL
USE BLEND.
BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND
WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON
CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND
THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER
OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS
BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE
LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES
FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST
AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE
BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION
LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY.
FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN
THE 20S.
TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY
MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND
WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN
CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE.
NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN
BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF
FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG
WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY
OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS
COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED
32 DEGREES.
STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT
INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE
BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS
FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY
TO RECOVER AT ALL MONDAY AND MAY EVEN DROP.
LONG TERM (TUE-FRI)...
MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC
AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO
NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT
SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK
FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
230 AM CST SAT JAN 14 2012
.DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES
TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR
DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL
USE BLEND.
BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND
WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON
CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND
THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER
OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS
BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE
LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES
FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST
AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE
BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION
LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY.
FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN
THE 20S.
TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY
MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND
WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN
CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE.
NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN
BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF
FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG
WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY
OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS
COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED
32 DEGREES.
STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT
INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE
BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS
FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY
TO RECOVER AT ALL MONDAY AND MAY EVEN DROP.
.LONG TERM (TUE-FRI)...
MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC
AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO
NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT
SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK
FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA.
&&
.AVIATION...
CIGS WILL CONTINUE TO FLOP BETWEEN VFR AND MVFR IN LIGHT SNOW BAND
AREA ALONG SOUTHERN VALLEY INTO WESTERN MN THIS MORNING. EXPECT MORE
VFR CONDITIONS ALONG AND WEST OF VALLEY. VSBYS IN -SN THIS
MORNING WILL BE PRIMARILY VFR WITH SOME BRIEF MVFR IN HEAVIER SNOW
SHOWERS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER/JIMMY K
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
352 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN
SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS
THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS
ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO
ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS
TO DEVELOP THIS EVENING.
BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE
ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON
QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL
STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND
LESSER AMOUNTS OVER SRN COALFIELDS.
WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW
AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY
WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW
MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH
THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE
ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS
OVER THE MOUNTAINS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
QUIET START TO THE PERIOD WITH HIGH PRESSURE TRUDGING EAST SUNDAY
NIGHT. SOUTHWESTERLY FLOW KICKS IN WITH H925 WINDS INCREASING TO
30-40 KNOTS BY 12Z. THIS FLOW WILL START TO PUSH SOME HIGH CLOUDS
IN TOWARDS MORNING...OTHERWISE SKIES WILL BE MOSTLY CLEAR. THE
WINDS WILL ALSO BE PUSHING IN WARMER AIR ALOFT...H925 TEMPERATURES
RISE FROM -6C AT 00Z TO +6 AT 12Z. MODELS STILL HAVE A SHARP
INVERSION NEAR THE SURFACE THROUGH THE NIGHT. STILL...WITH SUCH
STRONG WINDS ALOFT...THINK SOME OF THE WARMER AIR WILL MIX DOWN AND
ALLOW FOR RISING TEMPERATURES OVERNIGHT. SO...WENT WITH A MIN TEMP
CLOSE TO THE MET AROUND MIDNIGHT...WITH A NONDIURNAL RISE THEREAFTER.
ECMWF DOES LOOK LIKE A GOOD MIDDLE-OF-THE-ROAD APPROACH TO NEXT
SYSTEM...WITH A GENERALLY LARGE MODEL SPREAD. LOW PRESSURE DEVELOPS
IN THE PLAINS ON MONDAY...AND THEN TAKES OFF TO THE NORTHEAST
TOWARDS YYZ BY 00Z WEDNESDAY. SUPPORT WILL BE PROVIDED BY DEEPENING
SHORTWAVE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
VALLEY. SOME ISENTROPIC LIFT NOTED ON MONDAY...MUCH OF WHICH WILL GO
INTO MOISTENING THE ATMOSPHERE AT FIRST AND INCREASING CLOUD COVER.
SUFFICIENTLY DEEP MOISTURE ARRIVES BY 18Z AND ALLOWS THE FIRST
RAINDROPS IN SOUTHEAST OHIO. PWAT CONTINUES TO INCREASE IN THE
SOUTHWEST FLOW...EVENTUALLY REACHING AN INCH OR SO BY 12Z TUESDAY.
POPS CONTINUE TO TREND UPWARD...REACHING THEIR PEAK BY 12Z TUESDAY
WITH CATEGORICAL VALUES ACROSS MUCH OF THE AREA. SUPPORT FOR LIFT
WILL BE PROVIDED BY LFQ OF H250 JET ALONG WITH CONTINUED 290/295K
ISENTROPIC UPGLIDE. STILL...RAIN RATES SHOULD NOT BE
EXCESSIVE...AND AROUND A HALF INCH OF RAIN CAN BE EXPECTED FROM THIS
EVENT THROUGH 12Z TUESDAY. RAN CLOSER TO MET NUMBERS MONDAY/MONDAY
NIGHT...WHICH HAD A SMALLER DIURNAL RANGE THAN THE MAV.
THEREAFTER...WE AWAIT COLD FROPA WHICH WILL OCCUR LATER TUESDAY
AFTERNOON AND TUESDAY EVENING. ANOTHER .20 TO .30 INCH OF RAIN IS
POSSIBLE IN CONTINUED MOIST FLOW/LIFT. UNCERTAINTY WITH TIMING LEADS TO
UNCERTAINTY IN CHANGEOVER TO SNOW...BUT FOR NOW THINK THIS OCCURS
AFTER 00Z WEDNESDAY. BY THAT TIME...DEEPER MOISTURE IS DEPARTING
AND ONLY HAVE LIKELY POPS ALONG WESTERN SLOPES...WITH WINDS
BEGINNING THE TRANSITION TO WESTERLY AND EVENTUALLY NORTHWEST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
SURFACE HIGH PRESSURE STARTS THIS PERIOD WITH COLD H85 TEMPS. AS
SYSTEM SWINGS SOUTHEAST ON THURSDAY...COULD SEE SOME LIGHT SNOW
SHOWERS FOR A BRIEF PERIOD OF TIME. AS THIS SYSTEM QUICKLY MOVES
NORTHEAST...ANOTHER IS ON ITS HEELS. BY THE END OF THE WEEK...THIS
SYSTEM SHOULD REACH THE OHIO VALLEY. HOWEVER THIS TIME...WARMER AIR
ACCOMPANIES IT. THIS WOULD LEAD TO RAIN. HPC GUIDANCE HANDLES THIS
WELL. WILL USE HPC WITH SOME MINOR ADJUSTMENTS.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS
ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK
DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF
SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN
FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR
CONDITIONS IN PERIODS OF HEAVIER SNOW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT.
THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST
IN THE WESTERN LOWLANDS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H M M M M M M M M M M
HTS CONSISTENCY H H H M M M M M M H H H
BKW CONSISTENCY H H H M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY M M L L M M H H H H H H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 18Z SUNDAY...
IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/JB/CL
NEAR TERM...KMC
SHORT TERM...CL
LONG TERM...JB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
235 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN
SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS
THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS
ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO
ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS
TO DEVELOP THIS EVENING.
BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE
ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON
QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL
STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND
LESSER AMOUNTS OVER SRN COALFIELDS.
WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW
AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY
WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW
MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH
THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE
ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS
OVER THE MOUNTAINS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
NW UPSLOPE FLOW WILL CONTINUE EARLY IN THE PERIOD BEHIND EXITING
CLIPPER SYSTEM...WITH DRIER AND GRADUALLY WARMER WEATHER TAKING HOLD
FOR THE REMAINDER OF SUNDAY AS SURFACE HIGH PRESSURE AND UPPER
RIDGING TAKE HOLD ACROSS THE CWA OUT AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. WARM FRONT WILL BEGIN TO MOVE NORTH THROUGH THE CWA
BY LATE SUNDAY NIGHT OR EARLY MONDAY. DEPENDING ON TIMING...THIS MAY
MEAN WARMING TEMPERATURES OVERNIGHT SUNDAY NIGHT...BUT FOR
NOW...THINKING TIMING OF WARM FRONT ENTERING CWA WILL BE TOWARDS
MONDAY MORNING...AND THUS...ELECTED TO NOT DO A NON DIURNAL AT THIS
TIME. HOWEVER...PASSAGE OF WARM FRONTAL BOUNDARY/GOOD SOUTHERLY FLOW
DEVELOPING ACROSS THE CWA WILL ALLOW FOR NICE WARM TEMPERATURES ON
MONDAY...WITH MANY LOCATIONS WARMING INTO THE 40S TO 50S.
LOW PRESSURE TO THE WEST WILL CONTINUE TO APPROACH THE AREA ON
MONDAY...WITH MOISTURE SPREADING INTO THE AREA MONDAY EVENING. THIS
LOOKS TO BE A MOIST SYSTEM...AS STRONG LLJ...WITH A GOOD MOISTURE
TAP INTO THE GULF OF MEXICO...WILL RAISE PW VALUES TO BETWEEN 0.8 TO
1 INCH. THIS IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS
TIME OF YEAR. EXPECTING DECENT RAINFALL AMOUNTS WITH THIS SYSTEM DUE
TO EXPECTED MOISTURE...AS WELL AS THE FACT THAT THERE IS THE
POTENTIAL FOR SEVERAL WAVES EMBEDDED IN THE FLOW TO ENHANCE RAINFALL
AMOUNTS AT TIMES. FOR NOW...GENERALLY HAVE BETWEEN 0.6 TO 0.8 INCHES
OF RAIN FORECAST FOR THIS PERIOD. PROGRESSIVE NATURE SHOULD HELP
LIMIT EXCESSIVE RAINFALL. WITH GOOD WAA OUT AHEAD OF
SYSTEM...EXPECTING PRECIPITATION TO START OUT AS RAIN PRETTY MUCH
EVERYWHERE. EXCEPTION WOULD BE OVER SHELTERED VALLEYS OF POCAHONTAS
COUNTY...WHERE MODEL SOUNDINGS INDICATE POTENTIAL FOR VERY BRIEF
FZRA MONDAY NIGHT.
IN ADDITION TO RAIN...STRONG WINDS ALOFT ALONG WITH A DEVELOPING
TIGHT PRESSURE GRADIENT WILL CREATE RATHER GUSTY WINDS AT
TIMES...AND INCREASED FORECAST WINDS FROM PREVIOUS FORECAST AS A
RESULT.
COLD FRONT ASSOCIATED WITH THE LOW WILL SWEEP THROUGH THE AREA
TUESDAY NIGHT...WITH MUCH COLDER AIR FILTERING IN BEHIND THE FRONT.
THIS WILL RESULT IN A GRADUAL CHANGE OVER TO SNOW ACROSS THE CWA. AT
THIS POINT...ACCUMULATIONS APPEAR TO BE SOMEWHAT LIMITED AS
ATMOSPHERE SHOULD QUICKLY DRY OUT...AS IS OFTEN THE CASE. ALSO...AT
THIS POINT...DOESNT APPEAR AS THOUGH WE WILL HAVE A PROLONGED
UPSLOPE SNOW SHOWER EVENT BEHIND THE COLD FRONT...WHICH WILL ALSO
HELP TO LIMIT ACCUMULATIONS SOMEWHAT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE STARTS THIS PERIOD WITH COLD H85 TEMPS. AS
SYSTEM SWINGS SOUTHEAST ON THURSDAY...COULD SEE SOME LIGHT SNOW
SHOWERS FOR A BRIEF PERIOD OF TIME. AS THIS SYSTEM QUICKLY MOVES
NORTHEAST...ANOTHER IS ON ITS HEELS. BY THE END OF THE WEEK...THIS
SYSTEM SHOULD REACH THE OHIO VALLEY. HOWEVER THIS TIME...WARMER AIR
ACCOMPANIES IT. THIS WOULD LEAD TO RAIN. HPC GUIDANCE HANDLES THIS
WELL. WILL USE HPC WITH SOME MINOR ADJUSTMENTS.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS
ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK
DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF
SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN
FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR
CONDITIONS IN PERIODS OF HEAVIER SNOW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT.
THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST
IN THE WESTERN LOWLANDS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H M M M M M M M M M M
HTS CONSISTENCY H H H M M M M M M H H H
BKW CONSISTENCY H H H M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY M M L L M M H H H H H H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 18Z SUNDAY...
IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/JB/CL
NEAR TERM...KMC
SHORT TERM...SL
LONG TERM...JB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
217 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN
SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS
THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS
ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO
ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS
TO DEVELOP THIS EVENING.
BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE
ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON
QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL
STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND
LESSER AMOUNTS OVER SRN COALFIELDS.
WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW
AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY
WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW
MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH
THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE
ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS
OVER THE MOUNTAINS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
NW UPSLOPE FLOW WILL CONTINUE EARLY IN THE PERIOD BEHIND EXITING
CLIPPER SYSTEM...WITH DRIER AND GRADUALLY WARMER WEATHER TAKING HOLD
FOR THE REMAINDER OF SUNDAY AS SURFACE HIGH PRESSURE AND UPPER
RIDGING TAKE HOLD ACROSS THE CWA OUT AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. WARM FRONT WILL BEGIN TO MOVE NORTH THROUGH THE CWA
BY LATE SUNDAY NIGHT OR EARLY MONDAY. DEPENDING ON TIMING...THIS MAY
MEAN WARMING TEMPERATURES OVERNIGHT SUNDAY NIGHT...BUT FOR
NOW...THINKING TIMING OF WARM FRONT ENTERING CWA WILL BE TOWARDS
MONDAY MORNING...AND THUS...ELECTED TO NOT DO A NON DIURNAL AT THIS
TIME. HOWEVER...PASSAGE OF WARM FRONTAL BOUNDARY/GOOD SOUTHERLY FLOW
DEVELOPING ACROSS THE CWA WILL ALLOW FOR NICE WARM TEMPERATURES ON
MONDAY...WITH MANY LOCATIONS WARMING INTO THE 40S TO 50S.
LOW PRESSURE TO THE WEST WILL CONTINUE TO APPROACH THE AREA ON
MONDAY...WITH MOISTURE SPREADING INTO THE AREA MONDAY EVENING. THIS
LOOKS TO BE A MOIST SYSTEM...AS STRONG LLJ...WITH A GOOD MOISTURE
TAP INTO THE GULF OF MEXICO...WILL RAISE PW VALUES TO BETWEEN 0.8 TO
1 INCH. THIS IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS
TIME OF YEAR. EXPECTING DECENT RAINFALL AMOUNTS WITH THIS SYSTEM DUE
TO EXPECTED MOISTURE...AS WELL AS THE FACT THAT THERE IS THE
POTENTIAL FOR SEVERAL WAVES EMBEDDED IN THE FLOW TO ENHANCE RAINFALL
AMOUNTS AT TIMES. FOR NOW...GENERALLY HAVE BETWEEN 0.6 TO 0.8 INCHES
OF RAIN FORECAST FOR THIS PERIOD. PROGRESSIVE NATURE SHOULD HELP
LIMIT EXCESSIVE RAINFALL. WITH GOOD WAA OUT AHEAD OF
SYSTEM...EXPECTING PRECIPITATION TO START OUT AS RAIN PRETTY MUCH
EVERYWHERE. EXCEPTION WOULD BE OVER SHELTERED VALLEYS OF POCAHONTAS
COUNTY...WHERE MODEL SOUNDINGS INDICATE POTENTIAL FOR VERY BRIEF
FZRA MONDAY NIGHT.
IN ADDITION TO RAIN...STRONG WINDS ALOFT ALONG WITH A DEVELOPING
TIGHT PRESSURE GRADIENT WILL CREATE RATHER GUSTY WINDS AT
TIMES...AND INCREASED FORECAST WINDS FROM PREVIOUS FORECAST AS A
RESULT.
COLD FRONT ASSOCIATED WITH THE LOW WILL SWEEP THROUGH THE AREA
TUESDAY NIGHT...WITH MUCH COLDER AIR FILTERING IN BEHIND THE FRONT.
THIS WILL RESULT IN A GRADUAL CHANGE OVER TO SNOW ACROSS THE CWA. AT
THIS POINT...ACCUMULATIONS APPEAR TO BE SOMEWHAT LIMITED AS
ATMOSPHERE SHOULD QUICKLY DRY OUT...AS IS OFTEN THE CASE. ALSO...AT
THIS POINT...DOESNT APPEAR AS THOUGH WE WILL HAVE A PROLONGED
UPSLOPE SNOW SHOWER EVENT BEHIND THE COLD FRONT...WHICH WILL ALSO
HELP TO LIMIT ACCUMULATIONS SOMEWHAT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
GENERALLY USED ECMWF MEAN FOR THE PERIOD. A RAIN SYSTEM MOVES INTO
THE REGION MONDAY NIGHT AND TUESDAY...FOLLOWED BY ANOTHER COLD SNAP
TUESDAY NIGHT AND WEDNESDAY. COULD SEE SOME UPSLOPE SNOW
ACCUMULATIONS TUESDAY NIGHT AND WEDNESDAY WITH THE COLD AIR.
FORECAST GETS MUCH LOWER CONFIDENCE FOR THE END OF THE WORK WEEK AS
OPERATIONAL MODELS DIVERGE CONSIDERABLY.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS
ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK
DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF
SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN
FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR
CONDITIONS IN PERIODS OF HEAVIER SNOW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT.
THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST
IN THE WESTERN LOWLANDS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H M M M M M M M M M M
HTS CONSISTENCY H H H M M M M M M H H H
BKW CONSISTENCY H H H M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY M M L L M M H H H H H H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 18Z SUNDAY...
IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/JB/CL
NEAR TERM...KMC
SHORT TERM...SL
LONG TERM...RPY
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
642 AM EST SAT JAN 14 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH
PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES
AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT
LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE
WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH
ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY
BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVERGENCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND
THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE
NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A
MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE
LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE
REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE
EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY
STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM.
A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG
SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME
A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE
EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY
HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENDRITES IN
THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP
SNOW AMTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH.
BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK
SNOW WARN.
WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT
NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE
NORMAL FOR THE SECOND WEEK OF JANUARY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO
THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT
DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H
FLOW DOES NOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT
MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN
CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO
STAY JUST SUB-NORMAL THRU THE SHORT TERM PD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE
SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP
WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW
SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY
BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN
THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT
AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON
FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY
INCH OR TWO.
THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY
WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE.
THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE
NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY
CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF
INTERSTATE 80.
THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND
EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE
EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE
STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND
WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU
BY LATER SUNDAY NIGHT.
MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE
EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW
DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME
RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB
TO PLUS 3-6C ACROSS MUCH OF THE CWA.
THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY
TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH
AHEAD OF AN APPROACHING CFRONT.
COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY
WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW
SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY
NIGHT.
NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL
OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES
OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SFC ANALYSIS SHOWS A SECONDARY ARCTIC FRONT ACRS CNTRL NY THIS
MRNG...WHICH WILL SINK SWD INTO NRN PA THIS AFTN. HI RES MDL GUID
SHOWS LOW LEVEL CONVERGENCE ALONG THE FRONT HELPING TO ORGANIZE A
LONG-FETCH LAKE EFFECT BAND NEAR ERI-BFD-IPT LINE THIS AFTN. THE
EXACT LOCATION OF WHERE THE BAND WILL FORM AND HOW FAR SOUTH IT
WILL PROPAGATE IS STILL UNCERTAIN...BUT GIVEN THE CONSENSUS OF THE
HI RES DATA INDICATING PROXIMITY OF NRN TIER OF PA - REDUCED IPT
VIS TO MVFR AT 18Z. UNV MAY ALSO BE IMPACTED LATER TDY BUT FOR
NOW KEPT VIS VFR. OVERALL THERE ARE NO SIGNIFICANT CATEGORICAL
CHANGES TO 09Z INTERMEDIATE TAFS FOR THE 12Z SCHEDULED ISSUANCE.
COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE
GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW
SHOWERS. THE WORST FLYING CONDS WILL PERSIST ACROSS THE WRN
MTNS...WHERE VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST.
DOWNSLOPING FLOW E OF THE MTNS WILL RESULT IN ONLY SCT
FLURRIES IN MOST AREAS...WITH MVFR CIGS BCMG VFR AT UNV/AOO AND
LOW END SCT-BKN VFR CIGS AT LNS/MDT/IPT. SFC WNDS WILL GRADUALLY
VEER MORE TO THE WNW INTO TONIGHT.
OUTLOOK...
SUN...MVFR CIGS WEST...BCMG VFR.
MON...VFR BCMG MVFR MON NGT. LGT WINTRY MIX TO RAIN.
TUES...MVFR/IFR. STG FROPA WND SFT. GUSTY WINDS. -RA TO -SHSN.
WED...MVFR/IFR -SHSN WEST/VFR EAST. WINDY.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/STEINBUGL
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
406 AM EST SAT JAN 14 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH
PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES
AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT
LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE
WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH
ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY
BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVERGENCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND
THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE
NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A
MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE
LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE
REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE
EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY
STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM.
A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG
SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME
A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE
EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY
HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENDRITES IN
THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP
SNOW AMTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH.
BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK
SNOW WARN.
WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT
NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE
NORMAL FOR THE SECOND WEEK OF JANUARY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO
THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT
DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H
FLOW DOES NOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT
MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN
CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO
STAY JUST SUB-NORMAL THRU THE SHORT TERM PD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE
SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP
WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW
SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY
BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN
THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT
AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON
FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY
INCH OR TWO.
THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY
WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE.
THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE
NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY
CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF
INTERSTATE 80.
THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND
EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE
EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE
STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND
WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU
BY LATER SUNDAY NIGHT.
MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE
EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW
DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME
RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB
TO PLUS 3-6C ACROSS MUCH OF THE CWA.
THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY
TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH
AHEAD OF AN APPROACHING CFRONT.
COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY
WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW
SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY
NIGHT.
NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL
OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES
OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
09Z UPDATE...NO CHANGES TO 06Z SCHEDULED ISSUANCE.
COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE
GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW
SHOWERS. POOR FLYING CONDS WILL PERSIST ACROSS THE W MTNS...WHERE
VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST. DOWNSLOPING FLOW E
OF THE MTNS WILL RESULT IN ONLY SCT FLURRIES...WITH MVFR CIGS AT
UNV/AOO AND LOW END VFR AT LNS/MDT/IPT. W/SW WIND GUSTS BTWN
15-25KTS WILL BE COMMON THRU MOST OF THE DAY.
OUTLOOK...
SUN...MVFR CIGS WEST...BCMG VFR.
MON...VFR.
MON NGT...MVFR WEST/VFR EAST. -RA LKLY WEST.
TUES...MVFR AND IFR LKLY IN RA/SN.
WED...WINDY. MVFR AND IFR -SHSN W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/STEINBUGL
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
134 AM EST SAT JAN 14 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH
PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES
AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT
LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE
WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH
ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY
BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
CONVERGANCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND
THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE
NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A
MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE
LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE
REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE
EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY
STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM.
A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG
SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME
A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE
EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY
HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENRITES IN
THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP
SNOW AMOUTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH.
BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK
SNOW WARN.
WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT
NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE
NORMAL FOR THE SECOND WEEK OF JANUARY.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO
THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT
DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H
FLOW DOESNOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT
MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN
CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO
STAY JUST SUB-NORMAL THRU THE SHORT TERM PD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE
SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP
WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW
SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY
BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN
THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT
AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON
FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY
INCH OR TWO.
THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY
WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE.
THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE
NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY
CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF
INTERSTATE 80.
THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND
EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE
EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE
STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND
WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU
BY LATER SUNDAY NIGHT.
MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE
EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW
DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME
RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB
TO PLUS 3-6C ACROSS MUCH OF THE CWA.
THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY
TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH
AHEAD OF AN APPROACHING CFRONT.
COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY
WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW
SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY
NIGHT.
NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL
OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES
OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE
GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW
SHOWERS. POOR FLYING CONDS WILL PERSIST ACROSS THE W MTNS...WHERE
VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST. DOWNSLOPING FLOW E
OF THE MTNS WILL RESULT IN ONLY SCT FLURRIES...WITH MVFR CIGS AT
UNV/AOO AND LOW END VFR AT LNS/MDT/IPT. W/SW WIND GUSTS BTWN
15-25KTS WILL BE COMMON THRU MOST OF THE DAY.
OUTLOOK...
SUN...MVFR CIGS WEST...BCMG VFR.
MON...VFR.
MON NGT...MVFR WEST/VFR EAST. -RA LKLY WEST.
TUES...MVFR AND IFR LKLY IN RA/SN.
WED...WINDY. MVFR AND IFR -SHSN W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/STEINBUGL
AVIATION...FITZGERALD/STEINBUGL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1030 PM CST FRI JAN 13 2012
.DISCUSSION.../ISSUED AT 750 PM CST/
AREA OF LIGTH SNOW IN THE JAMES VALLEY CONTINUES TO FILL IN
ASSOCIATED WITH SOME 800-900MB FRONTOGENESIS. LATEST RUC SHOWS THAT
THIS TREND SHOULD CONTINUE THROUGH 06Z...SPREADING INTO THE I-29
CORRIDOR...THEN PULLING EASTWARD INTO MN AND IA AFTER 06Z THEN EAST
OF THE FORECAST AREA BY 12Z. AMOUNTS STILL LOOK TO BE RATHER LIGHT
WITH ONE HALF INCH OR LESS EXPECTED. OTHERWISE...STEADY TO SLOWLY
RISING TEMPERATURES OVERNIGHT AS FORECAST EARLIER STILL LOOK ON
TRACK.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR THROUGH MOST OF THE PERIOD...WITH OCCASIONAL MVFR CEILINGS AND
VISBILITIES THROUGH 12Z AS LIGHT SNOW MOVES SOOUTHEAST ACROSS THE
REGION. LOWER CLOUDS SHOULD DISSIPATE AFTER 12Z AND NORTHWEST WINDS
OF 15 TO 20 MPH WILL DEVELOP ON SATURDAY AND THEN BECOME LIGHT
TOWARDS SUNSET.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 300 PM CST/
LATEST WATER VAPOR LOOP SHOWING A FAIRLY STRONG WAVE DIGGING INTO
EASTERN MONTANA LATE THIS AFTERNOON WHICH WILL BRING THE SHOT OF
LIGHT SNOW TO THE AREA TONIGHT. STRONGER BAROCLINICITY CONFINED TO
THE LOWEST LEVELS OF THE ATMOSPHERE AND DO NOT EXPECT THIS TO PLAY
A BIG ROLE IN PRECIPITATION PRODUCTION. HIGHER UP...AROUND
700MB...NOT MUCH OF A THERMAL GRADIENT SO AT LEAST WITH THIS EVENT
PLANNING ON FOLLOWING THE UPPER LEVEL PV ADVECTION AS WELL AS THE
750-650MB THETA E RIDGING. THIS WILL BRING A CHANCE FOR SNOW INTO
CENTRAL SOUTH DAKOTA BETWEEN 0Z AND 3Z WITH AN INCREASING CHANCE
ACROSS CENTRAL PARTS OF THE CWA FROM ABOUT 3Z THROUGH 9Z...THEN
LIKELY PEELING INTO NORTHWEST IOWA FROM ABOUT 6Z THROUGH 12Z. NOT
PLANNING ON TOO MUCH ACCUMULATION WITH MOST LOCATIONS AN INCH OR
LESS. TEMPERATURES WILL REMAIN STEADY TO RISING THROUGH THE NIGHT AS
WELL WITH MORNING TEMPERATURES ABOUT 20 DEGREES WARMER THAN THIS
MORNING.
BY SATURDAY THE BULK OF THE ACTIVITY SHOULD BE EAST OF THE AREA WITH
A MARGINALLY BREEZY NORTHWEST DEVELOPING. HIGHS MOSTLY UNCHANGED
FROM EARLIER...RANGING FROM NEAR 30 IN THE NORTHERN CWA TO THE UPPER
30S IN THE SOUTH.
A SURFACE RIDGE SLIDES QUICKLY TO THE EAST ON SATURDAY NIGHT...WITH
A SOUTHERLY FLOW RETURNING TO THE AREA DURING THE NIGHT TIME HOURS
OUT AHEAD OF A TROUGH PUSHING OUT OF THE NORTHERN ROCKIES. WITH
THIS...TEMPERATURES WILL BE TRICKY ON SATURDAY NIGHT...INITIALLY
DROPPING PRETTY QUICKLY...THEN STEADYING OUT AND RISING IN SOME
AREAS OVERNIGHT WITH LOW LEVEL WARM AIR ADVECTION AND AN INCREASING
GRADIENT. LOWS EARLY LOOKING TO BE IN THE UPPER TEENS TO LOWER 20S.
SUNDAY WILL BE THE WARMEST DAY OF THE NEXT SEVERAL OUT AHEAD OF THE
APPROACHING SURFACE TROUGH. THOUGH WITH SOME MODEL
DIFFERENCES...MIXING LOOKS TO BE AROUND 925 MB...WHERE TEMPERATURES
WILL BE APPROXIMATELY IN THE RANGE OF 1 TO 7 DEGREES C FROM NORTH TO
SOUTH...AND HIGHS WILL BE FROM LOWER 40S NORTH OF THE INTERSTATE 90
CORRIDOR TO AROUND 50 FROM LAKE ANDES TO SIOUX CITY TO STORM LAKE.
COLD FRONT DROPS SOUTHWARD ACROSS THE REGION ON SUNDAY NIGHT
BRINGING AND END TO THE WARMTH...WITH LOWS IN THE UPPER TEENS TO MID
20S.
CONFIDENCE IN MONDAY/MONDAY NIGHT DETAILS RATHER LOW...WITH MODELS
SPLIT IN THE DETAILS REGARDING TIMING AND PLACEMENT OF MIDLEVEL
THERMAL GRADIENT AND SHORTWAVE TRACKING ACROSS THE CENTRAL PLAINS
DURING THAT TIME FRAME. DOES LOOK LIKE THERE WILL BE A PERIOD OF
LIGHT SNOW ACROSS THE AREA SOMETIME LATER ON MONDAY AND MONDAY
NIGHT...WITH MAYBE AN INCH TO INCH AND HALF OR SO OF ACCUMULATION
POSSIBLE AT THIS POINT. WILL BE SOMETHING TO WATCH HOWEVER. WITH
COLD AIR ADVECTION MONDAY WILL BE COLDER WITH HIGHS MAINLY IN THE
20S.
IN THE EXTENDED...TUESDAY THROUGH FRIDAY...APPEARS TO BE GENERALLY
COLD THROUGH THE PERIOD AS A SERIES OF REINFORCING SHORTWAVES TRACK
ACROSS THE NORTHERN PLAINS/UPPER MIDWEST IN A NORTHWESTERLY UPPER
LEVEL FLOW. CANNOT RULE OUT A COUPLE PERIODS OF LIGHT SNOW DURING
THAT TIME FRAME...THOUGH HARD TO PIN DOWN WITH USUAL MODEL
DIFFERENCES. TUESDAY AND THURSDAY LOOKING TO BE THE COLDEST
DAYS...IN THE TEENS...WARMING TO 20S TO LOWER 30S BY FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
940 PM CST SUN JAN 15 2012
.UPDATE...
CURRENT FORECAST IS IN GOOD SHAPE AND HAVE ONLY MADE SOME MINOR
ADJUSTMENTS TO THE HOURLY TEMPERATURES. STRONG SOUTHERLY FLOW
EXPECTED TO REMAIN IN PLACE THROUGH THE NIGHT WITH OVERCAST SKIES
ALREADY ACROSS MUCH OF THE REGION. TEMPERATURES SHOULD REMAIN
PRETTY CLOSE TO WHERE THEY ARE NOW THROUGH THE REMAINDER OF THE
NIGHT. 00Z SOUNDING INDICATED A RAPID INCREASE IN LOW LEVEL
MOISTURE BUT GIVEN THE LATEST CEILING HEIGHTS ACROSS THE REGION
THINK IT WILL BE SEVERAL MORE HOURS BEFORE WE WILL SEE ANY DRIZZLE
ACROSS NORTH TEXAS SO PUSHED THAT BACK UNTIL LATE TONIGHT.
OTHERWISE NO OTHER CHANGES NECESSARY.
DUNN
&&
.AVIATION...
FOR THE 00Z TAFS...MVFR CIGS ARE EXPECTED TO BUILD OVER NORTH TX
LATE THIS EVENING AND HOLD IN PLACE THRU MUCH OF THE DAY TOMORROW.
A 4 KFT STRATOCUMULUS DECK WAS HOLDING JUST SOUTH OF METROPLEX TAF
SITES AT 23Z...AND EXPECT THESE CLOUDS TO MOVE NORTH SHORTLY AFTER
00Z. AFTER SUNSET A 40 TO 50 KT LOW LEVEL JET IS EXPECTED TO
DEVELOP OUT OF THE SOUTH-SOUTHWEST. THIS WILL BRING A SHALLOW
LAYER OF GULF MOISTURE NORTH INTO NORTH TX BY LATE THIS EVENING.
THIS SHALLOW MOISTURE IS EXPECTED TO BE ACCOMPANIED BY A LOWER
STRATUS DECK WITH CIGS OF AROUND 1500 FT. THESE LOWER CIGS SHOULD
MOVE OVER WACO JUST BEFORE MIDNIGHT AND THEN MOVE OVER THE
METROPLEX TAF SITES A COUPLE OF HRS LATER.
SREF AND HRRR GUIDANCE CONTINUE TO ADVERTISE DRIZZLE OVER AREA TAF
SITES AFTER 09Z TONIGHT AND BRING CIGS AND VSBYS DOWN TO IFR OR
LOW IFR LEVELS BEFORE SUNRISE. MODELS CONTINUE TO ADVERTISE A WARM
AIR ADVECTION PATTERN OVER NORTH TX...WHICH MEANS THAT WIND
DIRECTION WILL VEER WITH HEIGHT. WITH H850 FLOW VEERED MORE OUT OF
THE SOUTHWEST THAN THE CORE OF THE H925 LLJ...THINK THAT THE
DEEPER FETCH OF GULF MOISTURE WILL TEND TO STAY EAST OF AREA TAF
SITES. WITH ONLY A SHALLOW SATURATED LAYER EXPECTED...THINK THAT
SUBSTANTIAL DRIZZLE WILL BE HARD TO COME BY AND HAVE GONE AHEAD
AND IGNORED THE IFR AND LOW IFR CIGS AND VSBYS FROM GUIDANCE AS A
RESULT. WILL MONITOR FOR SIGNS OF DRIZZLE DEVELOPMENT
OVERNIGHT...BUT A 2 KFT THICK SATURATED LAYER COMBINED WITH MEAGER
LIFT DOES NOT SEEM TO SUPPORT WIDESPREAD DRIZZLE OVER AREA TAF
SITES TONIGHT. SHALLOW MOISTURE SHOULD LIFT AND THEN SCATTER OUT
TOMORROW AFTERNOON.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 244 PM CST SUN JAN 15 2012/
GUSTY SOUTH WINDS HAVE RETURNED AND ARE BRINGING UP GULF MOISTURE
AND CLOUD COVER TO THE REGION. DUE TO THE CLOUDS...WINDS AND
INCREASING DEWPOINTS....IT WILL BE AN UNSEASONABLY WARM NIGHT WITH
LOW TEMPS IN THE 50S. MOISTURE/WARM ADVECTION IN THE LOW LEVELS
MAY BE STRONG ENOUGH TO SQUEEZE OUT A FEW SPRINKLES LATE TONIGHT
AND EARLY TOMORROW...BUT MEASURABLE RAIN IS NOT EXPECTED. WILL
CONTINUE TO CARRY A SLIGHT CHANCE OF SHOWERS OVER THE FAR EASTERN
ZONES TOMORROW AND TOMORROW EVENING AS THERE WILL BE A LITTLE CAPE
BELOW THE CAP. THINK THAT ANY ISOLATED THUNDERSTORMS WILL BE EAST
OF THE CWA WHERE MOISTURE IS HIGHER AND THE CAP IS WEAKER. WINDS
WILL VEER TO THE SOUTHWEST IN THE LOW LEVELS AND SHUNT THE CLOUD
COVER EASTWARD DURING THE AFTERNOON. IT WILL BE UNSEASONABLY WARM
WITH HIGHS IN THE 70S...BUT THOSE COULD APPROACH 80 IN THE WESTERN
ZONES WHERE MORE SUNSHINE IS EXPECTED.
MODEL GUIDANCE HAS UNANIMOUSLY SLOWED THE COLD FRONT DOWN ABOUT 3
HOURS ON TUESDAY AND THEREFORE WILL NUDGE UP BOTH THE LOW AND HIGH
TEMPS. COLD FRONT WILL STILL ARRIVE DURING THE MORNING HOURS...AND
NORTH WINDS OF 15 TO 25 MPH WILL RESULT IN STRONG COLD ADVECTION
DURING THE DAY. HIGH TEMPS WILL BE IN THE MORNING HOURS FOR MOST
AREAS...WITH TEMPS FALLING INTO THE MID 40S NORTH AND MID 50S
SOUTH BY MID-LATE AFTERNOON. WINDS DIMINISH AFTER SUNSET...AND
WITH CLEAR SKIES AND DRY AIR IN PLACE...TEMPS SHOULD FALL BELOW
FREEZING FOR JUST ABOUT THE WHOLE CWA. THE CENTER OF THE SURFACE
HIGH REMAINS NORTH OF THE REGION AND THUS THE LIGHT NORTHEAST
WINDS WILL HELP KEEP A FLOOR ON LOW TEMPS...BUT STILL SOME MID
20S ARE POSSIBLE OVER THE NORTHERN ZONES.
UPPER LEVEL PATTERN WILL REMAIN ZONAL INTO NEXT WEEKEND KEEPING
OUR WEATHER FAIR AND TRANQUIL. THE COOL-DOWN BEHIND THE FRONT WILL
BE RATHER BRIEF AND THE AIR MASS WILL MODIFY QUICKLY. SOUTH WINDS
RETURN WITH HIGHS WARMING INTO THE 50S BY WEDNESDAY...60S
THURSDAY...AND WITH THE AID OF SOUTHWEST WINDS...70S BY FRIDAY
AND SATURDAY. MOISTURE RETURN WILL BE SLOWER THAN NORMAL DUE TO
THE MORE WESTERLY FLOW IN THE LOW LEVELS...BUT BY SUNDAY DEWPOINTS
SHOULD BE IN THE 50S.
ECMWF/GFS AGREE THAT THE ZONAL FLOW WILL BUCKLE BY EARLY NEXT WEEK
WITH A FAST MOVING TROUGH COMING IN FROM THE PACIFIC. THIS WOULD
REPRESENT OUR BEST SHOT AT ANY RAIN...BUT BEST CHANCES MAY END UP
FAVORING THE EASTERN ZONES WHERE MOISTURE SHOULD BE HIGHER.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 57 76 52 57 29 / 5 5 5 5 0
WACO, TX 59 76 55 64 29 / 10 10 5 5 0
PARIS, TX 51 72 54 58 26 / 10 20 20 5 0
DENTON, TX 56 76 46 54 25 / 5 5 5 5 0
MCKINNEY, TX 55 75 50 56 25 / 10 10 10 5 0
DALLAS, TX 58 75 54 58 31 / 5 10 10 5 0
TERRELL, TX 56 72 57 62 28 / 10 10 10 5 0
CORSICANA, TX 58 72 59 65 30 / 10 10 10 10 0
TEMPLE, TX 59 76 56 67 30 / 10 10 5 10 0
MINERAL WELLS, TX 52 78 46 54 25 / 5 5 5 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
544 PM CST SUN JAN 15 2012
.AVIATION...
FOR THE 00Z TAFS...MVFR CIGS ARE EXPECTED TO BUILD OVER NORTH TX
LATE THIS EVENING AND HOLD IN PLACE THRU MUCH OF THE DAY TOMORROW.
A 4 KFT STRATOCUMULUS DECK WAS HOLDING JUST SOUTH OF METROPLEX TAF
SITES AT 23Z...AND EXPECT THESE CLOUDS TO MOVE NORTH SHORTLY AFTER
00Z. AFTER SUNSET A 40 TO 50 KT LOW LEVEL JET IS EXPECTED TO
DEVELOP OUT OF THE SOUTH-SOUTHWEST. THIS WILL BRING A SHALLOW
LAYER OF GULF MOISTURE NORTH INTO NORTH TX BY LATE THIS EVENING.
THIS SHALLOW MOISTURE IS EXPECTED TO BE ACCOMPANIED BY A LOWER
STRATUS DECK WITH CIGS OF AROUND 1500 FT. THESE LOWER CIGS SHOULD
MOVE OVER WACO JUST BEFORE MIDNIGHT AND THEN MOVE OVER THE
METROPLEX TAF SITES A COUPLE OF HRS LATER.
SREF AND HRRR GUIDANCE CONTINUE TO ADVERTISE DRIZZLE OVER AREA TAF
SITES AFTER 09Z TONIGHT AND BRING CIGS AND VSBYS DOWN TO IFR OR
LOW IFR LEVELS BEFORE SUNRISE. MODELS CONTINUE TO ADVERTISE A WARM
AIR ADVECTION PATTERN OVER NORTH TX...WHICH MEANS THAT WIND
DIRECTION WILL VEER WITH HEIGHT. WITH H850 FLOW VEERED MORE OUT OF
THE SOUTHWEST THAN THE CORE OF THE H925 LLJ...THINK THAT THE
DEEPER FETCH OF GULF MOISTURE WILL TEND TO STAY EAST OF AREA TAF
SITES. WITH ONLY A SHALLOW SATURATED LAYER EXPECTED...THINK THAT
SUBSTANTIAL DRIZZLE WILL BE HARD TO COME BY AND HAVE GONE AHEAD
AND IGNORED THE IFR AND LOW IFR CIGS AND VSBYS FROM GUIDANCE AS A
RESULT. WILL MONITOR FOR SIGNS OF DRIZZLE DEVELOPMENT
OVERNIGHT...BUT A 2 KFT THICK SATURATED LAYER COMBINED WITH MEAGER
LIFT DOES NOT SEEM TO SUPPORT WIDESPREAD DRIZZLE OVER AREA TAF
SITES TONIGHT. SHALLOW MOISTURE SHOULD LIFT AND THEN SCATTER OUT
TOMORROW AFTERNOON.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 244 PM CST SUN JAN 15 2012/
GUSTY SOUTH WINDS HAVE RETURNED AND ARE BRINGING UP GULF MOISTURE
AND CLOUD COVER TO THE REGION. DUE TO THE CLOUDS...WINDS AND
INCREASING DEWPOINTS....IT WILL BE AN UNSEASONABLY WARM NIGHT WITH
LOW TEMPS IN THE 50S. MOISTURE/WARM ADVECTION IN THE LOW LEVELS
MAY BE STRONG ENOUGH TO SQUEEZE OUT A FEW SPRINKLES LATE TONIGHT
AND EARLY TOMORROW...BUT MEASURABLE RAIN IS NOT EXPECTED. WILL
CONTINUE TO CARRY A SLIGHT CHANCE OF SHOWERS OVER THE FAR EASTERN
ZONES TOMORROW AND TOMORROW EVENING AS THERE WILL BE A LITTLE CAPE
BELOW THE CAP. THINK THAT ANY ISOLATED THUNDERSTORMS WILL BE EAST
OF THE CWA WHERE MOISTURE IS HIGHER AND THE CAP IS WEAKER. WINDS
WILL VEER TO THE SOUTHWEST IN THE LOW LEVELS AND SHUNT THE CLOUD
COVER EASTWARD DURING THE AFTERNOON. IT WILL BE UNSEASONABLY WARM
WITH HIGHS IN THE 70S...BUT THOSE COULD APPROACH 80 IN THE WESTERN
ZONES WHERE MORE SUNSHINE IS EXPECTED.
MODEL GUIDANCE HAS UNANIMOUSLY SLOWED THE COLD FRONT DOWN ABOUT 3
HOURS ON TUESDAY AND THEREFORE WILL NUDGE UP BOTH THE LOW AND HIGH
TEMPS. COLD FRONT WILL STILL ARRIVE DURING THE MORNING HOURS...AND
NORTH WINDS OF 15 TO 25 MPH WILL RESULT IN STRONG COLD ADVECTION
DURING THE DAY. HIGH TEMPS WILL BE IN THE MORNING HOURS FOR MOST
AREAS...WITH TEMPS FALLING INTO THE MID 40S NORTH AND MID 50S
SOUTH BY MID-LATE AFTERNOON. WINDS DIMINISH AFTER SUNSET...AND
WITH CLEAR SKIES AND DRY AIR IN PLACE...TEMPS SHOULD FALL BELOW
FREEZING FOR JUST ABOUT THE WHOLE CWA. THE CENTER OF THE SURFACE
HIGH REMAINS NORTH OF THE REGION AND THUS THE LIGHT NORTHEAST
WINDS WILL HELP KEEP A FLOOR ON LOW TEMPS...BUT STILL SOME MID
20S ARE POSSIBLE OVER THE NORTHERN ZONES.
UPPER LEVEL PATTERN WILL REMAIN ZONAL INTO NEXT WEEKEND KEEPING
OUR WEATHER FAIR AND TRANQUIL. THE COOL-DOWN BEHIND THE FRONT WILL
BE RATHER BRIEF AND THE AIR MASS WILL MODIFY QUICKLY. SOUTH WINDS
RETURN WITH HIGHS WARMING INTO THE 50S BY WEDNESDAY...60S
THURSDAY...AND WITH THE AID OF SOUTHWEST WINDS...70S BY FRIDAY
AND SATURDAY. MOISTURE RETURN WILL BE SLOWER THAN NORMAL DUE TO
THE MORE WESTERLY FLOW IN THE LOW LEVELS...BUT BY SUNDAY DEWPOINTS
SHOULD BE IN THE 50S.
ECMWF/GFS AGREE THAT THE ZONAL FLOW WILL BUCKLE BY EARLY NEXT WEEK
WITH A FAST MOVING TROUGH COMING IN FROM THE PACIFIC. THIS WOULD
REPRESENT OUR BEST SHOT AT ANY RAIN...BUT BEST CHANCES MAY END UP
FAVORING THE EASTERN ZONES WHERE MOISTURE SHOULD BE HIGHER.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 57 76 52 57 29 / 5 5 5 5 0
WACO, TX 59 76 55 64 29 / 10 10 5 5 0
PARIS, TX 51 72 54 58 26 / 10 20 20 5 0
DENTON, TX 56 76 46 54 25 / 5 5 5 5 0
MCKINNEY, TX 55 75 50 56 25 / 10 10 10 5 0
DALLAS, TX 58 75 54 58 31 / 5 10 10 5 0
TERRELL, TX 56 72 57 62 28 / 10 10 10 5 0
CORSICANA, TX 58 72 59 65 30 / 10 10 10 10 0
TEMPLE, TX 59 76 56 67 30 / 10 10 5 10 0
MINERAL WELLS, TX 52 78 46 54 25 / 5 5 5 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
320 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER AREA OF LOW PRESSURE ARRIVES FROM THE NORTHWEST TONIGHT
INTO EARLY SUNDAY...BRINGING ANOTHER ROUND OF MOUNTAIN SNOW
SHOWERS. HIGH PRESSURE WILL BUILD ACROSS THE AREA SUNDAY AND
OFFSHORE INTO MONDAY PROVIDING A GRADUAL MODERATION IN
TEMPERATURES FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 230 PM EST SATURDAY...
ISSUED A WSW FOR SOUTHWEST PORTIONS OF CWA TONIGHT INTO SUNDAY
MORNING FOR LIGHT SNOW EVENT ASSOCIATED WITH A FAST MOVING CLIPPER.
LEANING TOWARDS BLEND OF THE SREF AND NAM BELIEVE THERE IS ENOUGH
LOW LEVEL MOISTURE WITH SHORTWAVE TO PRODUCE 1 TO 3 INCHES OF SNOW
ACROSS THE HIGHER TERRAIN WITH A BURST OF SNOW ALONG THE WESTERN
SLOPES...ESPECIALLY IN THE NW NC MOUNTAINS WHERE UVV IS FORECAST TO
BE THE GREATEST. WITH LOCAL WRFARW-RNK AND HRRR EVEN SHOWING
MOISTURE SPREADING FURTHER EAST...DECIDED TO EXPAND AND INCREASE
CHANCES INTO THE MOUNTAINS AND ALLOW FOR SNOW FLURRIES TO SPILL EAST
INTO THE FOOTHILLS. PLAYED LOW TEMPERATURES TONIGHT CLOSE TO THE
ADJMAV WITH READINGS FROM AROUND 10 DEGREES WITH SNOWPACK IN THE
NORTHWEST MOUNTAINS TO THE MID 20S IN THE SOUTHEAST. SNOW SHOWERS
AND SNOW FLURRIES WILL END QUICKLY SUNDAY...WITH UPPER RIDGE AND SFC
HIGH BUILDING OVER THE REGION. WENT WITH HIGHS ON SUNDAY FROM THE
MID 20S IN THE NORTHWEST TO THE LOWER 40S IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM EST SATURDAY...
CHALLENGING PORTION OF THE FORECAST. HIGH PRESSURE ALTHOUGH LEAVING
SE WEST VA LATE SUNDAY NIGHT...SHOULD ALLOW DECOUPLING AND TEMPS TO
FALL NEAR DEWPOINT LEVELS. THIS WOULD PUT MOST SPOTS AT OR BELOW
GUIDANCE...ESPECIALLY THE SOUTHSIDE AND PIEDMONT WHERE HIGH PRESSURE
IS CENTERED AT 1Z/7A MONDAY. LAST FRAME OF RGEM SIMULATED SAT IMAGES
SHOWS AT LEAST THICK HIGH CLOUDS JUST THEN ENTERING THE SW QUARTER
OF OUR CWA ALSO AT THAT TIME...WITH A LATE SSW TO SW WIND DEVELOPING
LATE SUNDAY NIGHT. THUS...TEMPS MAY RISE LATE SUNDAY NIGHT ACROSS NW
NC AND EXTREME SW VA AFTER DECOUPLING EARLIER IN THE EVENING...BUT
WILL NOT TRY TO PUT THIS DETAIL IN THE HOURLY T GRIDS FOR NOW. WITH
THE CLOUDS THICKENING IN THE WEST MONDAY MORNING...AND THEN MOVING
EAST BY LATE DAY...TEMPS MAY HAVE A HARD TIME WARMING TO GUIDANCE
NUMBERS WITH MOSTLY CLOUDY SKIES AND A STEEP INVERSION IN PLACE WITH
H85 TEMPS UNLIKELY TO MIX TO THE SURFACE. CONSIDERING THIS
REGIME...MONDAY NIGHT`S FORECAST BECOMES ALL THE MORE
DIFFICULT...WITH TEMPS WARM ENOUGH ALOFT FOR RAIN...BUT RATHER LARGE
DEWPOINT DEPRESSION AND POSSIBLY SOME BROKEN CLOUD COVER...TEMPS
COULD FALL FAST IN THE SHELTERED VALLEYS WEST OF THE BLUE
RIDGE...FOR SOME POSSIBLE FREEZING RAIN...BEFORE TEMPS WARM AFTER
MIDNIGHT TO ABV FREEZING. DID HAVE TO PUT IN HOURLY T GRIDS FOR THIS
PERIOD...AS LESS CLOUDS IN THE EXTREME EAST MAY ALLOW THOSE PARTS TO
DECOUPLE AGAIN...WHEREAS TEMPS FALL INITIALLY IN SE WEST VA THEN
RISE SLIGHTLY AFTER MIDNIGHT. GROUND ALSO WILL BE RATHER COOL
CONSIDERING FEW DAY STRING OF MORE WINTERLIKE TEMPS INCLUDING LOWS IN
THE MID AND UPPER TEENS SUNDAY NIGHT. FOR NOW...COMBINED A SLT CHC
OF FREEZING RAIN FOR A FEW HOURS WITH REGULAR RAIN TO HIGHLIGHT THIS
THREAT. H85 TEMPS THEN AT 12Z/7A TUESDAY SITTING AROUND +6C SHOULD
EVEN WITH THE RAIN AROUND ALLOW TEMPS TO PUSH 60F EAST OF THE BLUE
RIDGE AND MAYBE EVEN ROANOKE TOO...WITH A DOWNSLOPING WIND AND WARM
SURGE AHEAD OF THE NEXT POTENT BAROCLINIC BOUNDARY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM EST SATURDAY...
A COLD FRONT WILL ROLL ACROSS THE REGION TUESDAY EVENING WITH RAIN
SHOWERS ENDING AROUND MIDNIGHT. VERY COLD AIR AND A TIGHT PRESSURE
GRADIENT WILL THEN BRING WINDY AND GUSTY CONDITIONS TO THE
AREA...ALONG WITH WESTERN UPSLOPE SNOW SHOWERS INTO WEDNESDAY
MORNING. THE WIND AND SNOW WILL BE BRIEF AS HIGH PRESSURE BUILDS
INTO THE REGION WEDNESDAY AFTERNOON. HIGH PRESSURE DRIFTS OFF THE
EAST COAST...WHILE A DISTURBANCE TRACKS OVER THE NORTHERN OHIO
VALLEY THURSDAY. THIS DISTURBANCE IS FAR ENOUGH AWAY FROM THE AREA
TO KEEP POPS LOW AND CONFIDED TO THE GREENBRIER VALLEY/ALLEGHANY
HIGHLANDS THURSDAY EVENING. ANOTHER DISTURBANCE IS EXPECTED TO TRACK
ACROSS THE OHIO VALLEY FRIDAY NIGHT AND SATURDAY. THIS DISTURBANCE
HAS PACIFIC ORIGIN AND WILL BE WARM WHEN IT ENTERS THE REGION.
COLD TEMPERATURES WILL HANG AROUND TUESDAY NIGHT INTO WEDNESDAY
NIGHT. AS THE CHILLY HIGH PRESSURE SYSTEM MOVES OFF THE COAST AND
ZONAL FLOW IS ESTABLISHED ON THURSDAY...TEMPERATURES WILL MODERATE
ABOVE NORMAL FRIDAY AND SATURDAY.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
AS OF 1134 AM EST SATURDAY...
SCT TO BKN MVFR CLOUDS IN THE WESTERN MOUNTAINS THIS AFTERNOON.
OTHERWISE...VFR CONDITION EXPECTED. GUSTY NORTHWEST WINDS ACROSS
THE HIGHER TERRAIN MAY HINDER AVIATION OPERATIONS.
A LAYER OF CLOUDS AROUND 5K FEET WILL SPREAD EAST ACROSS CWA
LATE THIS AFTERNOON AND EARLY THIS EVENING AT ALL TAF SITES.
A UPPER LEVEL DISTURBANCE WILL MOVE THROUGH OUR AREA TONIGHT
BRINGING A REINFORCEMENT OF COLD AIR AND SNOW SHOWERS TO KBLF AND
KLWB. SNOW OR SNOW FLURRIES MAY EVEN PUSH INTO KBCB/KROA LATE
TONIGHT INTO SUNDAY MORNING. MVFR CIGS WILL RETURN FOR KBLF AND
KLWB INTO SUNDAY.
SHOULD SEE ALL SITES RETURN TO VFR UNDER HIGH PRESSURE ON MONDAY
WITH ANOTHER FRONT BRINGING ADDED CHANCES OF RAIN AND LOW CIGS BY
TUESDAY. WITH COLDER AIR COMING IN WEDNESDAY...MOUNTAINS SNOW
SHOWERS AND SNOW FLURRIES ARE POSSIBLE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 9 AM EST SUNDAY FOR VAZ007-009-
015.
NC...WINTER WEATHER ADVISORY UNTIL 9 AM EST SUNDAY FOR NCZ001-018.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...KK/PH
SHORT TERM...KM
LONG TERM...RCS
AVIATION...KK/PH
AREA FORECAST DISCUSSION
NWS SPOKANE WA
416 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...
00Z TAFS: Cold upper level low will place the threat of -shsn in all
forecasts. Most of the activity will remain near KPUW and KLWS in an
axis of instability however it will also follow a compact upper
level disturbance which was heading into the southern WA Cascades as
of 00z. -SHSN are psbl at KEAT and KMWH through 06z or so and brief
pds of ifr/mvfr cigs and vsbys will be psbl but should be
short-lived. The low will shift into xtrm E WA and N ID aft 06z and
this will bring a good chance of prolonged showers to KPUW and KLWS
through Mon AM with IFR conditions expected. The chances for IFR
-shsn are smaller at KGEG KSFF and KCOE as several guidance packages
keep most of the pcpn south of these sites. Much will depend on
track of surface low associated with upper level trough. 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 LA CROSSE WI
844 PM CST SUN JAN 15 2012
.SHORT TERM...
844 PM CST SUN JAN 15 2012
THE POSSIBILITY FOR FREEZING DRIZZLE TONIGHT APPEARS TO BE
DIMINISHING. THE 00Z KDVN SOUNDING WAS NOT SATURATED AT ALL IN THE
LOW LEVELS WHILE THE KGRB SOUNDING WAS MORE FAVORABLE. SATELLITE
AND SURFACE OBSERVATIONS SHOWING THE LOW STRATUS CLOUDS ARE
BEGINNING TO FORM OVER CENTRAL WISCONSIN WHERE THE LOW LEVEL
MOISTURE IS THE DEEPEST. LOOKING AT THE 00Z RUC BUFKIT SOUNDINGS
AND 00Z NAM PLAN VIEW DATA...IT NOW APPEARS THE ONLY PLACE WHERE
SATURATION MAY OCCUR IS IN THE I94 CORRIDOR AS THE RUC BUFKIT
SOUNDINGS STILL SATURATE KAUW AND TO A LESSER DEGREE KEAU. THE NAM
925 MB RH DATA CONFIRMS THIS AND ONLY HAS 90+ RH OVER CENTRAL INTO
NORTHEAST WISCONSIN. WILL UPDATE THE FORECAST TO REMOVE THE
FREEZING DRIZZLE FROM ALL BUT THE I94 CORRIDOR AND PUSH BACK THE
TIMING TO AFTER 05Z.
.LONG TERM...THURSDAY THROUGH SUNDAY
245 PM CST SUN JAN 15 2012
ECMWF...GFS AND GEM ALL FAVOR DRIVING AN UPPER LEVEL SHORTWAVE
TROUGH FROM THE PLAINS TO ACROSS THE MID MISSISSIPPI RIVER VALLEY
THU NIGHT-FRI. SOME DIFFERENCES IN PLACEMENT AND TIMING OF THIS
FEATURE...WITH THE EC THE QUICKER OF THE THREE. BOTH THE EC AND GFS
PRODUCE AN AREA OF PCPN NORTH OF THE MAIN PACKET OF ENERGY...AND
WOULD BRING THE POTENTIAL FOR A FEW INCHES OF ACCUMULATION TO THE
FORECAST AREA. THE GEM IS MORE ROBUST WITH A SHORTWAVE IN THE
NORTHERN STREAM...PRODUCING MORE QPF WITH IT AND LITTLE/IF ANY WITH
ITS PLAINS SHORTWAVE. LIKE THE CONSISTENCY OF THE GFS/EC FOR NOW AND
WILL CONTINUE WITH PCPN CHANCES IN THIS PERIOD. SOUTHERN FLOW
RETURNS FOR THE WEEKEND...AND AFTER A MID WEEK COOL DOWN...LOOK
FOR SEASONABLE TO MILD TEMPERATURES IN THIS PERIOD.
&&
.AVIATION...TONIGHT AND MONDAY
534 PM CST SUN JAN 15 2012
THE BIG QUESTION IS WHETHER FREEZING DRIZZLE WILL DEVELOP THIS
EVENING AT KLSE AND POINTS TO THE EAST. THE 15.18Z NAM CONTINUES
TO BE VERY AGGRESSIVE WITH THE DEVELOPMENT OF A LOW LEVEL
SATURATED LAYER AND THE FREEZING DRIZZLE IN THIS LAYER. VERY
CONCERNED THOUGH THAT THE NAM IS OVER DONE WITH ITS LOW LEVEL
SATURATION. WITH ABOVE FREEZING TEMPERATURES TODAY THE MODEL COULD
BE MELTING OFF TOO MUCH SNOW USING THIS MOISTURE TO HELP SATURATE
THE LOW LEVELS. LOOKING AT THE BUFKIT SOUNDING FOR KLSE...THE NAM
WOULD SUGGEST THAT THE LOW LEVELS SHOULD ALREADY BE SATURATED WITH
LOW STRATUS CLOUDS IN PLACE. HOWEVER...THE SURFACE TEMP/DEW POINT
SPREADS ARE AT LEAST 6 DEGREES ACROSS THE ENTIRE FORECAST AREA AND
DOWNSTREAM INTO IOWA AND ILLINOIS AND SATELLITE IMAGES SHOW NO
SIGNS OF ANY STRATUS. THE STRONGEST WARM AIR ADVECTION AND LIFT IN
THE 0-2KM LAYER SHOULD COME ACROSS THE AREA THIS EVENING...SO
STILL SOME POTENTIAL FOR THIS TO DEVELOP. SO FOR NOW...HAVE LEFT
THE LOW CLOUDS AND FREEZING DRIZZLE IN THE KLSE FORECAST BUT DID
PUSH THE STARTING TIME BACK A LITTLE. HAVE ALSO MAINTAINED THE IFR
CEILINGS AT BOTH SITES...BUT AGAIN...CONCERNED THAT THIS MAY NOT
DEVELOP AS THERE IS NO SIGN OF THIS IN THE 15.18Z GFS GUIDANCE. ENDED
THE FREEZING DRIZZLE SOONER THAN THE PREVIOUS FORECAST AS BOTH
THE NAM AND 15.21Z RUC INDICATE THE LIFT THROUGH THE SATURATED
LAYER BECOMES VERY WEAK A FEW HOURS BEFORE THE FRONT COMES
THROUGH. ONCE THE FRONT COMES THROUGH...THE WINDS WILL COME AROUND
TO THE NORTHWEST AND THEN WEST WITH SATELLITE AND OBS SHOWING MVFR
CEILINGS BEHIND THE FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
3245 PM CST SUN JAN 15 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
534 PM CST SUN JAN 15 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
245 PM CST SUN JAN 15 2012
FORECAST FOCUS IS ON THE PCPN POTENTIAL OVER THE NEXT FEW
DAYS...WITH PERIODS OF FREEZING DRIZZLE POSSIBLE...ALONG WITH MINOR
ACCUMULATIONS OF SNOW.
FRONTAL BOUNDARY WILL SWEEP WEST TO EAST ACROSS THE REGION LATE
TONIGHT-EARLY MONDAY MORNING...WITH A STRONG SOUTHERLY FETCH OUT
AHEAD OF IT. AMPLE LOW LEVEL WARM AIR ADVECTION AND ISENTROPIC
UPGLIDE THROUGH 12Z MONDAY...WITH A DECENT FETCH OF 925-850 MB
MOISTURE TRANSPORT THROUGH THE NIGHT-TIME HOURS. THE SOUTHERLY WINDS
WILL RIDE ACROSS A 4-6 INCH SNOW PACK ACROSS EASTERN IOWA/NORTHERN
ILL...MODERATING THE TEMPS DOWN...BUT MORE IMPORTANTLY...PICKING UP
A LOT OF MOISTURE. BOUNDARY LAYER RH WILL INCREASE IN RESPONSE TO
THIS...AND THE 15.12 NAM/GFS CONTINUE TO PICK UP ON THIS...WITH THE
NAM THE MORE AGGRESSIVE IN BLOSSOMING THE LOW SITUATION TONIGHT. ITS
PROBABLY TOO AGGRESSIVE...BUT THE TREND LOOKS GOOD. BUFKIT SOUNDINGS
AHEAD OF THE FRONT SHOW THIS INCREASE IN RH WELL...UPWARDS OF 2500
FT DEEP. WITH STRONG THERMODYNAMICS THROUGH THIS SATURATED
LAYER...ALONG WITH TURNING FROM SOUTH-SOUTHEAST TO WEST AT THE TOP
OF THE LAYER...DRIZZLE LOOKS PROBABLE. WHILE THE GFS IS NOT AS
ROBUST AS THE NAM...IT SUGGESTS DRIZZLE ALSO. WITH SFC TEMPS SUB
FREEZING...IT WOULD BE FREEZING DRIZZLE...AND ICING THEN BECOMES A
CONCERN. SIGNALS HAVE BEEN FAIRLY CONSISTENT OVER THE PAST FEW MODEL
RUNS...INCREASING FORECAST CONFIDENCE. WILL BROADEN THE COVERAGE AND
INCREASE WORDING FROM PATCHY TO AREAS FOR SOME LOCATIONS IN THE
NORTH WHERE SATURATION/CLOUDS ARE EXPECTED FIRST. IF FREEZING
DRIZZLE BECOMES WIDESPREAD...FREEZING RAIN ADVISORIES WILL BE
NEEDED. CONDITIONS WILL HAVE TO BE MONITORED CLOSELY.
LATER ON MONDAY AND INTO TUESDAY AN UPPER LEVEL SHORTWAVE TROUGH
WILL MOVE ACROSS THE PLAINS...AND THEN WORK ON THE SOUTHERN/WESTERN
PORTIONS OF THAT SFC FRONT. MODELS CONTINUE TO SHOW PRETTY GOOD
CONSISTENCY OVER THEIR PAST FEW RUNS...AND THE 15.12Z FOLLOW
SUIT...KEEPING THE BULK OF THE PCPN WITH THIS SHORTWAVE/FRONT
INTERACTION SOUTH OF THE FORECAST AREA. SOME HINTS THAT SOME SNOW
COULD WORK INTO SOUTHWEST WI OVERNIGHT MONDAY...BUT MOST OF THE
LOCAL AREA/S PCPN CHANCES WILL COME FROM A DIFFERENT SHORTWAVE.
THIS PARTICULAR RIPPLE IN THE UPPER LEVEL FLOW WILL SLIDE FROM THE
SOUTHERN ROCKIES...ACROSS THE PLAINS...AND THEN OVER THE REGION TUES
MORNING. GOOD QG CONVERGENCE IN THE 300-700 MB LAYER WITH THIS
SHORTWAVE...ALONG WITH ISENTROPIC UPGLIDE ON THE 285-305 K SFCS.
BUFKIT SOUNDINGS AND TIME/HEIGHT X-SECTIONS INDICATE THE SYSTEM WILL
BRING ENOUGH MOISTURE WITH IT FOR PCPN PRODUCTION. SOUNDINGS ALSO
POINT TO A FAIRLY DEEP...UPWARDS OF 10 KFT AT TIMES...DENDRITIC ZONE
GROWTH REGION...WHICH FAVORS HIGHER SNOW RATIOS AND ACCUMULATIONS.
ITS A QUICK MOVING SYSTEM THOUGH...AND THE BEST SNOW CHANCES APPEAR
TO BE IN THE 06-18Z TUE TIME FRAME. THINK 1 TO 3 LOOKS REASONABLE AT
THIS TIME.
ALL THAT SAID...MONDAY EVENING POSES SOME POTENTIAL PROBLEMS.
NORTH-SOUTH RUNNING X-SECTIONS VIA THE NAM AND GFS HAVE ONLY LOW
SATURATION ACROSS THE FORECAST AREA...NOT SATURATING THE COLUMN
UNTIL OVERNIGHT. WITH ISENTROPIC UPGLIDE THROUGH THE CLOUD
LAYER...FREEZING DRIZZLE WOULD...YET AGAIN...BECOME MORE PROBABLE.
HAVE ADDED SOME MENTION OF THIS FOR MONDAY EVENING ACROSS THE
SOUTHERN 1/2 OF THE FORECAST AREA. THERE IS SOME SUGGESTION THAT
THIS FREEZING DRIZZLE POSSIBILITY COULD BE SPREAD ACROSS THE ENTIRE
FORECAST AREA...AND LAST MOST OF THE NIGHT. WILL START WITH THIS
THOUGH AND SEE HOW THIS SCENARIO EVOLVES.
.LONG TERM...THURSDAY THROUGH SUNDAY
245 PM CST SUN JAN 15 2012
ECMWF...GFS AND GEM ALL FAVOR DRIVING AN UPPER LEVEL SHORTWAVE
TROUGH FROM THE PLAINS TO ACROSS THE MID MISSISSIPPI RIVER VALLEY
THU NIGHT-FRI. SOME DIFFERENCES IN PLACEMENT AND TIMING OF THIS
FEATURE...WITH THE EC THE QUICKER OF THE THREE. BOTH THE EC AND GFS
PRODUCE AN AREA OF PCPN NORTH OF THE MAIN PACKET OF ENERGY...AND
WOULD BRING THE POTENTIAL FOR A FEW INCHES OF ACCUMULATION TO THE
FORECAST AREA. THE GEM IS MORE ROBUST WITH A SHORTWAVE IN THE
NORTHERN STREAM...PRODUCING MORE QPF WITH IT AND LITTLE/IF ANY WITH
ITS PLAINS SHORTWAVE. LIKE THE CONSISTENCY OF THE GFS/EC FOR NOW AND
WILL CONTINUE WITH PCPN CHANCES IN THIS PERIOD. SOUTHERN FLOW
RETURNS FOR THE WEEKEND...AND AFTER A MID WEEK COOL DOWN...LOOK
FOR SEASONABLE TO MILD TEMPERATURES IN THIS PERIOD.
&&
.AVIATION...TONIGHT AND MONDAY
534 PM CST SUN JAN 15 2012
THE BIG QUESTION IS WHETHER FREEZING DRIZZLE WILL DEVELOP THIS
EVENING AT KLSE AND POINTS TO THE EAST. THE 15.18Z NAM CONTINUES
TO BE VERY AGGRESSIVE WITH THE DEVELOPMENT OF A LOW LEVEL
SATURATED LAYER AND THE FREEZING DRIZZLE IN THIS LAYER. VERY
CONCERNED THOUGH THAT THE NAM IS OVER DONE WITH ITS LOW LEVEL
SATURATION. WITH ABOVE FREEZING TEMPERATURES TODAY THE MODEL COULD
BE MELTING OFF TOO MUCH SNOW USING THIS MOISTURE TO HELP SATURATE
THE LOW LEVELS. LOOKING AT THE BUFKIT SOUNDING FOR KLSE...THE NAM
WOULD SUGGEST THAT THE LOW LEVELS SHOULD ALREADY BE SATURATED WITH
LOW STRATUS CLOUDS IN PLACE. HOWEVER...THE SURFACE TEMP/DEW POINT
SPREADS ARE AT LEAST 6 DEGREES ACROSS THE ENTIRE FORECAST AREA AND
DOWNSTREAM INTO IOWA AND ILLINOIS AND SATELLITE IMAGES SHOW NO
SIGNS OF ANY STRATUS. THE STRONGEST WARM AIR ADVECTION AND LIFT IN
THE 0-2KM LAYER SHOULD COME ACROSS THE AREA THIS EVENING...SO
STILL SOME POTENTIAL FOR THIS TO DEVELOP. SO FOR NOW...HAVE LEFT
THE LOW CLOUDS AND FREEZING DRIZZLE IN THE KLSE FORECAST BUT DID
PUSH THE STARTING TIME BACK A LITTLE. HAVE ALSO MAINTAINED THE IFR
CEILINGS AT BOTH SITES...BUT AGAIN...CONCERNED THAT THIS MAY NOT
DEVELOP AS THERE IS NO SIGN OF THIS IN THE 15.18Z GFS GUIDANCE. ENDED
THE FREEZING DRIZZLE SOONER THAN THE PREVIOUS FORECAST AS BOTH
THE NAM AND 15.21Z RUC INDICATE THE LIFT THROUGH THE SATURATED
LAYER BECOMES VERY WEAK A FEW HOURS BEFORE THE FRONT COMES
THROUGH. ONCE THE FRONT COMES THROUGH...THE WINDS WILL COME AROUND
TO THE NORTHWEST AND THEN WEST WITH SATELLITE AND OBS SHOWING MVFR
CEILINGS BEHIND THE FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
3245 PM CST SUN JAN 15 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
246 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...QUITE A BIT OF UNCERTAINTY EXISTS DURING THE TAF
PERIOD. CURRENT TRENDS WERE CHALLENGING ENOUGH. CIGS WERE MAINLY
MVFR NORTH AND WEST OF THE FOX VALLEY AND VFR OVER THE REST OF THE
AREA. THERE WERE ALSO SCATTERED MVFR VSBYS IN LIGHT SNOW AND/OR
HAZE. A LAKE EFFECT BAND OVER LAKE MICHIGAN WAS DRIFTING TOWARD
WISCONSIN AS A TROUGH/FRONT APPROACHED THE STATE FROM THE WEST.
THINK THERE WILL BE SOME LIGHT SNOW OR FLURRIES GOING ON MUCH OF
THE NIGHT WITH MOSTLY MVFR CIGS AS THE SURFACE BOUNDARY APPROACHES
FROM THE WEST. TIME/HEIGHT SECTIONS INDICATED A DECREASE IN LOW
LEVEL MOISTURE AFTER ABOUT 15Z SUNDAY WITH SOME MID CLOUDS ABOVE
THAT. PAY EXTRA ATTENTION TO CURRENT CONDITIONS AND WATCH FOR TAF
UPDATES IF YOU PLAN TO FLY IN THE AREA THIS AFTERNOON THROUGH
SUNDAY MORNING.
MG
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MG/JKL
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1205 PM CST SAT JAN 14 2012
.UPDATE...FLURRIES OVER THE EASTERN CWA DIMINISHING AS DRIER MID
LEVEL AIR ADVECTS IN. CLOUD COVER THINNER AND MORE SCATTERED THAN
PREVIOUSLY EXPECTED...BUT ENOUGH SNOW COVER IS PRESENT THAT
SUNSHINE HAS NOT HAD A BIG IMPACT ON TEMPS. BUMPED HIGHS DOWN
SLIGHTLY. BIGGEST CHANGE TO AFTERNOON PERIOD WILL BE POPS.
ISENTROPIC ANALYSIS NO LONGER SHOWS NECESSARY INGREDIENTS FOR
PRECIP FORMATION. THIS IS BACKED UP BY LATEST 3KM HRRR OUTPUT.
WILL BACK OFF TO SLIGHT CHANCE...KEEPING IT IN THE WEST.
&&
.AVIATION/18Z TAFS/...FLURRIES STILL LINGERING FROM MADISON AND
EASTWARD. SHOULD SEE FLURRIES DIMINISH THROUGH THE AFTERNOON AS
THE LOW LEVELS DRY OUT. SKIES ARE MAINLY VFR NOW ACROSS SRN
WI...BUT COULD STILL SEE A FEW SPOTS OF BRIEF MVFR CIGS AS THINGS
SLOWLY DRY OUT.
WEAK WAVE TO SLIDE THROUGH THIS EVENING...BUT LOOKING EVEN WEAKER
AND DRIER WITH LATEST MODELS. THOUGH FLURRIES MAY BE POSSIBLE FROM
AROUND MADISON AND SOUTHWEST...CHANCES LOOK LOW ENOUGH TO REMOVE
FROM MSN TAFS. MODELS SATURATE THE LOW LEVELS FOR A TIME BEHIND
THE WAVE LATE TONIGHT INTO SUNDAY MORNING...SO PUT SOME MVFR CIGS
IN THE TAFS.
&&
.PREV DISCUSSION... /ISSUED 341 AM CST SAT JAN 14 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
BACK EDGE OF LOW CLOUDS HAVE BEEN MOVING STEADILY EWD AT 12KTS SINCE
FRI EVE...HOWEVER HAVE NOTICED SLIGHT SLOWING OF PROGRESSION EWD
SINCE 07Z. LOW LEVEL CYCLONIC CURVATURE AND BULK OF CLOUDS IN
DENDRITIC GROWTH ZONE BELOW INVERSION WL CONTINUE TO SHAKE OUT SOME
FLURRIES THIS MRNG...ESPECIALLY IN THE SOUTHEAST. SLIGHTLY DRIER
AIR SETTLING IN FROM THE NORTHEAST WL HELP TO END THE FLURRIES MOST
AREAS.
LOW LEVEL THERMAL TROUGH LINGERS ACROSS EASTERN WI THRU MID-AFTN...
SO EXPC LOW CLOUDS TO HANG ON INTO THE AFTN. UPSTREAM SHORT WAVE
AND ASSOCIATED SWIRL SHOWS UP CLEARLY ON WATER VAPOR IMAGERY OVR ERN
SASK PUSHING INTO SW MANITOBA. SHORT TERM GUIDANCE IN GOOD
AGREEMENT ON CARRYING THIS WAVE SOUTHEAST AND ACROSS SW WI THIS
EVE. EXPC WAVE TO WEAKEN AS IT MOVES ACROSS OUR REGION DUE TO
UPSTREAM SUBSIDENCE SPREADING RAPIDLY EWD INTO THE NRN PLAINS AND
UPPER MIDWEST...AHEAD OF NEXT STRONGER WAVE PUSHING THRU SW CANADA.
CONDENSATION PRESSURE DEFICITS ON 280 THETA SFC LOWER TO LESS THAN
10MB WITH WEAK ISENTROPIC UPGLIDE BY LATE AFTN OVER WRN CWA.
WL INCREASE TO LKLY WORDING IN FAR WEST BY LATE AFTN. AREA OF LOWER
CPD AFFECTS REST OF SOUTH CENTRAL WI THRU THE EARLY EVE...HOWEVER
WEAK FORCING CONTINUES TO DIMINISH. THINK THERE WILL BE AREAS OF
VERY LIGHT SNOW AROUND SOUTH CENTRAL...AND PARTS OF SOUTHEAST IN THE
EVE...BUT MANY LOCATIONS WL NOT RECEIVE MEASURABLE QPF. HENCE WL
KEEP POPS ON THE LOW SIDE...AND NEXT SHIFT WL BE ABLE TO TWEAK.
WHILE WEAK FORCING LINGERS OVER SOUTH CENTRAL WI DURING THE LATE
EVENING...MID LEVELS DRY OUT. HENCE VERY SMALL THREAT OF PATCHY
FREEZING DRIZZLE FOR A FEW HOURS. CLOUDS EXPCD TO HANG ON THRU LATE
TNGT IN WEAK FLOW.
SHORT TERM...SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM.
WARM AIR ADVECTION CONTINUES ON SUNDAY ACROSS THE AREA. SURFACE
PRESSURE GRADIENT TIGHTENS ACROSS THE AREA...WHICH SHOULD ALLOW
FOR BREEZY SOUTH SOUTHEAST WINDS. SKIES SHOULD GRADUALLY SCATTER
OUT AS THE DAY GOES ON...WHICH SHOULD ALLOW TEMPERATURES TO RISE
INTO THE LOWER TO PERHAPS MID 30S.
AREA REMAINS IN WARM SECTOR SUNDAY NIGHT...AS COLD FRONT
APPROACHES FROM THE NORTHWEST. NAM CONTINUES TO BE ONLY SHORT TERM
MODEL TO PRODUCE VERY LIGHT QPF WITH THE FRONT SUNDAY NIGHT. AREA
FORECAST SOUNDINGS FROM NAM ARE QUITE DRY EXCEPT THE BOUNDARY
LAYER DURING THIS TIME...WITH THE GFS SIMILAR. THUS...WILL
CONTINUE DRY FORECAST SUNDAY NIGHT. TEMPERATURES WILL REMAIN MILD
WITH SOUTH WINDS AHEAD OF THE FRONT.
COLD FRONT SLIDES SOUTHEAST THROUGH THE FORECAST AREA ON MONDAY.
NAM CONTINUES TO SHOW VERY LIGHT QPF IN THE MORNING...WITH THE
OTHER SHORT TERM MODELS DRY IN THE MORNING. NAM/CANADIAN/ECMWF
THEN SHOW LIGHT QPF IN THE FAR SOUTHEAST COUNTIES MONDAY
AFTERNOON...WITH THIS AREA ON NORTHERN PERIPHERY OF LOW LEVEL
FRONTOGENESIS BAND. AREA FORECAST SOUNDINGS FROM NAM/GFS SHOWING
AIR COLUMN HAVING A TOUGH TIME SATURATING...MAINLY IN THE 850MB TO
500MB LAYER. FOR NOW...WILL MAINTAIN CHANCE POPS FOR MONDAY.
TEMPERATURES WOULD SUPPORT LIGHT SNOW IN THE MORNING...AND A MIX
IN THE AFTERNOON IN THE SOUTHEAST AS TEMPERATURES WARM.
NAM/GFS/CANADIAN MODELS ARE TAKING SURFACE LOW FROM CENTRAL/WEST
CENTRAL MISSOURI TO SOUTHEAST LOWER MICHIGAN/NORTHWEST OHIO MONDAY
NIGHT...WITH THE ECMWF SLOWER AND ONLY IN NORTHERN INDIANA BY 12Z
TUESDAY. 850MB BAROCLINIC ZONE AND LOW LEVEL FRONTOGENESIS
RESPONSE SHIFT SOUTHEAST THROUGH THE AREA MONDAY EVENING...THEN
SOUTHEAST OF THE AREA LATER MONDAY NIGHT. THEY ALSO BRING
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION INTO THE AREA MONDAY
NIGHT. THE ECMWF KEEPS THE 850MB BAROCLINIC ZONE OVER THE AREA
THROUGH THE NIGHT...WITH THE SHORTWAVE TROUGH STILL WEST OF THE
REGION. WILL FOLLOW THE NAM/GFS/CANADIAN TRENDS AND KEEP LIKELY
POPS GOING IN THE SOUTHEAST CORNER OF THE AREA...WITH CHANCE POPS
ELSEWHERE.
GFS/ECMWF CONTINUE TO DIFFER ON TUESDAY...WITH THE ECMWF BRINGING
A MORE AMPLIFIED SHORTWAVE TROUGH THROUGH THE REGION. THIS HELPS
CYCLOGENESIS WITH THE DOWNSTREAM SURFACE LOW. THE GFS IS LESS
AMPLIFIED BUT STILL BRINGS THIS FEATURE THROUGH THE AREA. GFS ALSO
SHOWING MID LEVEL FRONTOGENESIS BAND STAYING WEST AND NORTH OF THE
AREA. STILL...BOTH MODELS SHOWING LIGHT QPF OF UP TO 0.15 INCHES
ON THE ECMWF ON TUESDAY. WILL CONTINUE LIKELY POPS FOR LIGHT SNOW.
AT THIS TIME...IT APPEARS THAT SNOW ACCUMULATIONS WOULD BE ON THE
LIGHTER SIDE THAN PREVIOUSLY THOUGHT. STILL...THIS SYSTEM NEEDS TO
BE WATCHED IN CASE IT SLOWS DOWN AND AMPLIFIES. BRISK NORTHWEST
WINDS WILL BRING COLDER AIR INTO THE AREA...AND WOULD HELP BLOW
AND DRIFT ANY NEW FALLEN SNOW. STAY TUNED.
LONG TERM...TUESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE
LOW TO MEDIUM.
WEAK HIGH PRESSURE RIDGE TUESDAY NIGHT BRINGS QUIET
WEATHER...BEFORE ECMWF/GFS SHOW DIFFERENCES WITH WEAKER SYSTEMS
FOR THE REST OF THE WEEK. THEY BRING ALBERTA CLIPPER SYSTEM
SOUTHEAST THROUGH THE REGION LATER WEDNESDAY INTO WEDNESDAY
NIGHT...GFS QUICKER THAN THE ECMWF. THESE MODELS THEN DIFFER QUITE
A BIT WITH FEATURES LATER IN THE WEEK. FOR NOW...WILL GO WITH
CONSENSUS POPS AND TEMPERATURES FOR THIS PERIOD GIVEN THE FAIR
AMOUNT OF UNCERTAINTY FROM THE MODELS.
AVIATION/12Z TAFS/...BACK EDGE OF MVFR CEILINGS OVER SW WI HAS BEEN
MOVING STEADILY EWD AROUND 12KTS...BUT HAVE NOTICED A SLIGHT SLOWING
IN LAST SEVERAL 11-3.9 MICRON IMAGES SINCE 08Z. WEAK CYCLONIC
CURVATURE AND BULK OF LOW LEVEL MOISTURE IN DENDRITIC GROWTH ZONE WL
CONTINUE TO SHAKE OUT FEW FLURRIES THIS MRNG ESPECIALLY IN SOUTHEAST
AS SLIGHTLY DRIER AIR SETTLES IN FROM THE NORTH.
WL GRADUALLY RAISE CEILINGS IN EAST TO VFR BUT LOW CLOUDS COULD VERY
WELL HANG ON ALL DAY AS LOW LEVEL THERMAL TROUGH WL BE SLOW TO MOVE
OFF TO THE EAST. WL HOLD ONTO LOW VFR CIGS IN EAST WITH A SMALL
THREAT FOR VERY LIGHT SNOW THIS EVE AS WEAKENING SHORT WAVE SLIDES
THRU THE REGION. WL TAKE CIGS AND VSBYS BRIEFLY DOWN IN KMSN AS
SOUTH CENTRAL WI WL BE CLOSER TO DEEPER MOISTURE AND BETTER WEAK
LIFT.
MARINE...QUIET CONDITIONS EXPCD IN THE SHORT TERM AS WEAK HIGH
PRESSURE LINGERS OVER LAKE MI INTO TNGT. STRENGTHENING LOW PRESSURE
IS EXPECTED TO MOVE THROUGH SRN CANADA ON SUN AND MON RESULTING IN A
TIGHTENING PRESSURE GRADIENT OVER THE WRN GTLAKES. THE LOW WILL
PULL A COLD FRONT THROUGH THE AREA ON MONDAY RESULTING IN BRISK SW
WINDS TURNING TO THE N-NW. WIND SPEEDS WL LIKELY REACH SMALL CRAFT
LEVELS DURING THIS PD.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WIMBERLEY/DDV
TODAY/TONIGHT AND AVIATION/MARINE...MBK
SUNDAY THROUGH FRIDAY...WOOD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1154 PM CST SUN JAN 15 2012
.AVIATION...
WILL KEEP VFR CONDITIONS MOST OF THE OVRNGT WITH S/SE WINDS
10-15 KTS AND GUSTY SLOWLY DIMINISHING AS FRONT APPROACHES.
HAVE KEPT LLWS IN FCST WITH 45-50 KT LOW LEVEL JET AROUND
2000 FT AGL BUT BEST POTENTIAL NEXT FEW HRS BEFORE WINDS DROP
OFF AND JET VEERS. MAIN CHALLENGE THEN REMAINS ONSET OF LOW
CLOUDS AND FOG. SOME MODELS CONTINUE VERIFYING TOO MOIST WHICH
MAKES FOR LOWER CONFIDENCE ON TIMING. LATEST NAM AND RUC MODELS
APPEAR TO BE COMING MORE IN LINE WITH OBSERVATIONS OF BEING SLOWER
WITH LOW LEVEL MOISTURE. HAVE THEREFORE CONTINUED TO DELAY ONSET
OF LOW CLOUDS AND FOG UNTIL AROUND 12Z-16Z. EXPECT CONDITIONS TO
DETERIORATE INTO MVFR TO IFR CAT WITH THE LOW CLOUDS AND FOG...
WITH SOME DZ/FZDZ POSSIBLE AS WELL... AND EVEN PATCHY LIGHT RAIN
OVER SOUTHEAST IA. LOCALLY LIFR OR VLIFR CONDITIONS POSSIBLE IN
DENSE FOG BY LATE DAY AND VERY EARLY EVE AS WINDS BECOME VERY
LIGHT AHEAD OF WEAK SFC LOW MOVING ALONG STALLED BOUNDARY. AS THE
LOW MOVES EAST DURING EVE EXPECT WINDS TO TURN WESTERLY AT 5-10
KTS WITH GRADUAL IMPROVEMENT ON VSBYS AND CIGS.
&&
.PREV DISCUSSION... /ISSUED 908 PM CST SUN JAN 15 2012/
UPDATE...
PREVIOUS MODELS OVERALL VERIFYING TOO MOIST WHEN COMPARED WITH
00Z DVN RAOB. 00Z NAM HOWEVER HAS COME IN DRIER AND MORE
REASONABLE BASED ON OBSERVATIONS. 925 MB CONVERGENCE (35 KTS
AT SLATER IA VWP COMPARED WITH 5 KTS AT WOOD LAKE MN VWP) WILL
FOCUS MAIN LOW CLOUD DEVELOPMENT TO OUR NORTH LATE EVE INTO THE
OVRNGT. MAIN SURGE OF STRATUS WITHIN DEEPER LOW LEVEL MOISTURE
PUSHING NWD THROUGH EASTERN OK AND WESTERN AR ATTIM. THESE
CLOUDS LIKELY TO MOVE OR DEVELOP ACROSS THE SOUTHERN CWA LATE TNGT.
BASES LIKELY TO BE AOA 3KFT WHICH NOT SUPPORTIVE OF DZ AND HAVE
REMOVED MENTION OVRNGT. PRESSURE GRADIENT AND LOW LEVEL JET TO
CONTINUE AIDING GUSTY WINDS INTO THE OVRNGT... BUT DO EXPECT THEM
TO DROP OFF WEST OF THE MISSISSIPPI RVR AS A FRONTAL ZONE
APPROACHES. WITH BL STAYING WELL MIXED MOST OF THE NGT AND
BETTER LOW LEVEL MOISTURE DELAYED HAVE ALSO REMOVED FOG MENTION.
LOW LEVEL THERMAL RIDGE IS PROGGED INTO CWA OVRNGT... WHICH
COUPLED WITH GUSTY WINDS MAY LEAD TO STEADY OR EVEN A BIT OF RISE
ON TEMPS IN SOME AREAS... BUT BANKING ON DIMINSHING WIND LATE TO
ALLOW DROP OFF TO FCST LOWS.
PREV DISCUSSION... /ISSUED 322 PM CST SUN JAN 15 2012/
SYNOPSIS...
LOW PRESSURE WAS LOCATED ALONG THE NORTH DAKOTA/CANADA BORDER
EARLY THIS AFTERNOON. A WARM FRONT EXTENDED SOUTH FROM THE LOW
THROUGH WESTERN IA AND WESTERN MO. STRONG SOUTHERLY FLOW AHEAD OF
THE FRONT HAS PUSHED TEMPERATURES INTO THE LOW 40S OVER THE
SOUTHWESTERN CWFA WITH TEMPERATURES STRUGGLING THROUGH THE LOW 30S
IN THE NORTHEAST. THE AIRMASS WAS ALSO DRY WITH ONLY SOME THIN CI
LIFTING NORTH THROUGH THE AREA THIS AFTERNOON. THE NORTHERN
PLAINS LOW WAS LOCATED AHEAD OF A POTENT UPPER TROF DIGGING INTO
THE PACIFIC NORTHWEST. AT 12Z HEIGHT FALLS AHEAD OF THE TROF WERE
AROUND 150M AT 300MB AND 500MB.
SHORT TERM...TONIGHT AND MONDAY...
THE NORTHERN PLAINS SURFACE LOW WILL HEAD NORTHEAST INTO EASTERN
ONTARIO BY MONDAY AFTERNOON. THE WARM FRONT WILL PUSH EAST ACROSS
THE REGION THIS EVENING. A COLD FRONT WILL DROP SOUTHEAST THROUGH
THE REGION MONDAY MORNING AND EARLY AFTERNOON.
MAIN CONCERNS TONIGHT WILL BE THE POTENTIAL SATURATION OF THE LOW
LEVELS LEADING TO SOME FOG AND FREEZING DRIZZLE NORTH AND DRIZZLE SOUTH.
THE NAM IS THE MOST AGGRESSIVE WITH THIS SCENARIO SHOWING THE NEAR
SURFACE LAYER SATURATING BY 03Z OVER THE NORTHERN CWFA. HOWEVER
THE NAM WAS NOT VERIFYING ITS 2M TEMPERATURES AND DEWPOINTS VERY
WELL SO FAR TODAY. WITH LOW CONFIDENCE IN THE TIMING AND EXTENT OF
SATURATION TONIGHT OPTED TO KEEP A MENTION OF DZ/FZDZ AND FOG
AFTER MIDNIGHT. IF THE DRIER GFS VERIFIES THEN THESE CONDITIONS
WILL HOLD OFF UNTIL MONDAY MORNING. TEMPERATURES WILL BE HIGHLY
DEPENDENT ON THE CLOUD DEVELOPMENT TONIGHT SO ALLOWED FOR PLENTY
OF ROOM TO FALL WITH THE POTENTIAL FOR KEEPING MOSTLY CLEAR SKIES
THROUGH THE EVENING.
MONDAY THE COLD FRONT WILL BE MOVING THROUGH THE CWFA DURING THE
MORNING AND EARLY AFTERNOON. EXPECT STRATUS/DRIZZLE/FOG BEHIND
THE FRONT WITH THE POTENTIAL FOR SOME FREEZING DRIZZLE IN THE
NORTH DURING THE MORNING. A SURGE OF LOW LEVEL MOISTURE WITH MOVE
OVER THE SOUTHERN CWFA AHEAD OF THE FRONT EARLY MONDAY. THIS
SHOULD RESULT IN MORE WIDESPREAD DRIZZLE AND FOG FOR THE SOUTH
WITH THE MID LEVELS REMAINING DRY. HOWEVER...A CHANCE OF RAIN WAS
MAINTAINED WITH SOME FORCING OCCURRING WITH THE FROPA. EXTENSIVE
CLOUD COVER...SOME LIGHT PRECIPITATION AND THE FROPA SHOULD KEEP
TEMPERATURES FROM RISING TOO MUCH SO ALLOW FOR 5 TO 10 DEGREE RISE
MOST AREAS. ..DLF..
LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...
MONDAY NIGHT...LATEST 12Z RUN MODELS IN GOOD AGREEMENT OF SUGGESTING
APPROACHING L/W TROF TO INDUCE WAVE DEVELOPMENT ON PASSING SFC
FRONTAL BOUNDARY ACRS CENTRAL IL AND THEN PROPAGATE UP INTO
NORTHEASTERN INDIANA THROUGH TUE MORNING. SOME SECONDARY ELEVATED
FRONTOGENETICAL FORCING BETWEEN THIS LLVL CYCLOGENESIS AND THE
APPROACHING UPPER TROF SHOULD LINGER PRECIP ACRS MUCH OF THE
SOUTHEASTERN 2/3S OF THE DVN CWA MON EVENING. BUT MOISTURE DEPTH
FOR THIS LIFT TO UTILIZE TO GENERATE MUCH OF ANY MEASURABLE PRECIP
STILL APPEARS MARGINAL AT THIS POINT AFTER THE LIGHT RAIN EXITS THE
EAST EARLY...THUS IT MAY BE MORE OF A TRANSITION BACK TO A DRIZZLE
PHENOMENA MON EVENING AND OVERNIGHT. AND WITH SFC TEMPS COOLING IN
THE INCOMING LLVL COLD CONVEYOR IT COULD LEAD TO SOME FREEZING
DRIZZLE. FCST SOUNDINGS FLUCTUATE WITH JUST ENOUGH SATURATION FOR
FLURRIES OR LIGHT SNOW OR JUST DRIZZLE SO WILL MENTION BOTH FREEZING
DRIZZLE OR LIGHT SNOW FOR MOST OF THE NIGHT. APPROACHING TROF INDUCES
ENOUGH TOP-DOWN SATURATION AND THUS ICE NUCLEI FOR ALL SNOW FROM THE
WEST LATE IN THE WESTERN AND NORTHWESTERN CWA...BUT THIS PROCESS TO
BE MORE REALIZED ON TUE. A FEW TENTHS OF NEW SNOWFALL POSSIBLE BY
TUE MORNING IN THE NORTHWEST. WILL GO WITH LOWS IN THE TEENS IN THE
NORTHWEST...AND THE MID 20S IN THE SOUTHEAST.
TUESDAY AND WEDNESDAY...LATEST GUIDANCE STILL SUGGESTS THAT THE
SFC CYCLONE TO CONTINUE TO DEEPEN ACRS THE GRT LKS ON TUE AND
PROBABLY BELOW 1K MB JUST EAST OF THE DETROIT AREA. TIGHT CYCLONIC
GRADIENT TO THE WEST OF THIS PROCESS AND ROBUST CAA TO MAKE FOR
WINDY RAW CONDITIONS ON TUE WITH NORTHWESTERLY GUSTS POSSIBLY UP TO
35+ MPH AT TIMES. WIND CHILLS IN THE SINGLE DIGITS TO AROUND ZERO
EVEN DURING THE DAY. UPPER TROF AND ELEVATED FORCING TO PRODUCE
WIDESPREAD LIGHT SNOW AND FLURRIES...WITH AREAS ALONG AND NORTH OF
I80 GETTING UP TO AT LEAST AN INCH OF NEW SNOWFALL. THE SNOWS TO LAST
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 ALONG THE HWY 20 CORRIDOR.
CLEARING AND COLD CONDITIONS TUE NIGHT WITH PASSING LLVL RIDGE
LOBE...SOME LOWS BELOW ZERO POSSIBLE IN AREAS NORTH OF I80...
OTHERWISE SINGLE DIGITS ABOVE ZERO. 12Z RUNS STILL SUGGEST A PASSING
CLIPPER ACRS MN/WI IN FRESHLY ESTABLISHED BROAD NORTH-WESTERLIES...
TO USHER YET ANOTHER FRONT INTO THE CWA BY LATE WED NIGHT WITH
POSSIBLE FLURRIES OR POST FRONTAL LIGHT SNOW IN THE NORTH BY THU
MORNING. BIG TIMING DIFFERENCES WITH THIS INCOMING FROPA BETWEEN THE
MEDIUM RANGE SOLUTIONS...WITH THE GFS THE QUICKEST AND COLD AIR
ADVECTING CWA-WIDE BY THU MORNING WITH LOWS BACK INTO THE TEENS AND
SINGLE DIGITS...WHILE THE SLOWER ECMWF HAS PRE-FRONTAL WAA KEEPING
TEMPS AROUND 30 IN THE SOUTHEASTERN CWA THROUGH 12Z THU. WOULD BET
ON THE MORE PROGRESSIVE GFS IN THIS TYPE OF STEERING FLOW AND WILL
LEAN TOWARD THOSE LOW TEMP VALUES...BUT FOR NOW KEEP THE FCST DRY
THROUGH 12Z THU.
THURSDAY THROUGH FRIDAY...LLVL BAROCLINICITY STILL TO GET ALIGNED
PARALLEL UNDER THESE MEAN FLOW NORTH-WESTERLIES ACRS OR NEAR THE
DVN 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. BUT
LATEST RUNS ARE TRENDING DRY WITH A PASSING SFC RIDGE THU AND THU
EVENING AFTER MORNING FLURRIES EXIT THE SOUTHEASTERN FCST AREA. THE
NEW 12Z RUN GFS AND ECMWF CONTINUE TO 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...BUT ARE CONTINUE TO VARY FROM RUN-TO-RUN HOW FAR NORTH OR
SOUTH THIS FEATURE WILL TRACK. THEY STILL SUGGEST A WAVE STRONG
ENOUGH TO PRODUCE 1-3 OR EVEN 2-4 INCHES OF SNOW ACRS THE NORTHERN
THIRD OR SO OF THE DVN CWA FROM LATE THU NIGHT INTO FRI...WITH
ENOUGH OF A WARM DRAW ALOFT TO PRODUCE A MIX OF FREEZING RAIN...RAIN
OR SNOW IN THE SOUTH HALF. WILL KEEP MODERATE CHC POPS GOING FOR SNOW
ON FRI FOR NOW...AND CONTINUE A MIX OF RAIN AND SNOW IN THE SOUTH.
SATURDAY AND SUNDAY...LONG RANGE SIGNALS 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.
THERMAL PROFILES ARE ALMOST THERE TO SUPPORT HIGHS NEAR 50 BY NEXT
SAT 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. BUT THE NEW 12Z ECMWF SUGGESTS IF NOT
50 DEGREES ON SAT...SOUTHERLY MIXING FLOW WILL DO IT ON SUNDAY.
THIS IN CONTRAST TO THE GFS WHICH SAGS A LLVL BOUNDARY DOWN ACRS
THE AREA AND HANGS IT UP PARALLEL UNDER DEVELOPING SOUTH-WESTERLIES.
THIS FEATURE WOULD THEN ACT AS A LLVL MOISTURE CONVERGENT FOCAL POINT
FOR CLOUD...FOG AND POSSIBLE LIGHT RAIN DEVELOPMENT AS THE DAY
PROGRESSES. STILL MILD WITH HIGHS IN THE 40S. REGIONAL COLLABORATION
SUPPORTS MORE OF A GFS/ECMWF BLEND AND THAT IS WHAT WILL BE
ADVERTISED IN THE GRIDS WITH LOW CHANCES FOR LIGHT RAIN...BUT FEEL
THE DRY MILD ECMWF WILL WIN OUT WITH DELAY IN ADEQUATE MOISTURE RETURN.
12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1217 AM EST MON JAN 16 2012
UPDATED AVIATION DISCUSSION FOR THE 06Z TAFS
.SHORT TERM /TONIGHT THROUGH MONDAY/... ISSUED AT 415 PM EST
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 06Z TAF ISSUANCE/...
STRATUS HAS DEVELOPED ACROSS MUCH OF THE AREA AS EXPECTED. ALSO...
MORE FAVORABLE UPSLOPE COMPONENT OFF LAKE MICHIGAN HAS LED TO LOWEST
CIGS AT KSAW AS EXPECTED. IFR CIGS SHOULD CONTINUE AT KSAW FOR THE
NEXT FEW HRS BEFORE WINDS VEER SLIGHTLY...REDUCING UPSLOPING AND
ALLOWING CIGS TO RISE BACK TO LOW MVFR. MVFR CIGS SHOULD DEVELOP AT
KIWD/KCMX...THOUGH LOWER MVFR CIGS WILL PROBABLY HOLD OFF UNTIL COLD
FROPA IN THE MORNING WHEN WINDS SHIFT TO AN UPSLOPE COMPONENT. MVFR
CIGS SHOULD THEN PREVAIL AT ALL TERMINALS THRU THE END OF THE FCST
PERIOD...THOUGH WOULD NOT BE SURPRISED IF CLOUDS SCATTER OUT FOR A
WHILE AT TIMES IN THE AFTN.
&&
.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 LSZ249>251-263-264-266-267.
GALE WARNING UNTIL 1 AM EST MONDAY LSZ244-245-265.
LAKE MICHIGAN...
GALE WARNING UNTIL 7 AM EST MONDAY LMZ248-250.
&&
$$
SHORT TERM...KF
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1107 PM CST SUN JAN 15 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.UPDATE.../ISSUED 758 PM CST SUN JAN 15 2012/
STRATUS NOW BEGINNING TO FORM ACROSS WI...THOUGH MUCH FURTHER EAST
THAN GUIDANCE WAS INDICATING EARLIER THIS AFTERNOON. IN
ADDITION...925 MB RH FORECASTS FROM THE RUC HAVE BEEN TRENDING THE
LOW STRATUS/FZDZ FURTHER EAST AS WELL WITH EACH SUBSEQUENT RUN. AS
A RESULT...UPDATED THE WEATHER GRID TO SHUNT FZDZ MENTION FURTHER
EAST...WITH ONLY A MENTION LEFT FOR LADYSMITH AND THE ERN SLIVERS
OF CHIP AND EAU CLAIRE COUNTIES IN WI. BEST FZDZ POTENTIAL LOOKS
TO REMAIN EAST OF THE MPX CWA AT THIS POINT...BUT WILL CONTINUE TO
MONITOR CLOSELY.
&&
.PREV DISCUSSION...
/ISSUED 555 PM CST SUN JAN 15 2012/
ANOTHER VERY WARM DAY TODAY ACROSS THOSE PARTS OF THE AREA THAT
DON`T HAVE SNOW ON THE GROUND WHERE LOWER AND MID 40S APPEARED.
SNOW COVER ACROSS WC WI HELD TEMPS BACK IN THE MID 30S. BREEZY SOUTH
WINDS AHEAD OF CDFNT PLOWING ACROSS THE DKTS HAS PUSHED TEMPS TO
AROUND 50 NEAR THE IA BORDER IN SW MN.
CONCERN FOR THE OVERNIGHT IS WITH STRATUS TO FORM AHEAD OF CDFNT
MAINLY OVER THE SNOWPACK IN WI. SREF PROB CIGS AOA 1000 FT
CONTINUES WITH RAPID BLOSSOMING OF CLDS BY 06Z ACROSS THAT AREA. NAM
CONTINUES TO KNOCK OUT .01 QPF. PROGGED SOUNDSINGS SHOW THAT
FAVORED PCPN TYPE WOULD BE -FZDZ WITH ELEVATED WARM LAYER AND NO ICE
CRYSTAL FEEDERS FROM ABOVE.
TEMPS IN WAKE OF COLD FRONT CRASH QUICKLY WITH A FAIRLY COLD AIRMASS
BUILDING IN BEHIND. CURRENT TEMPS IN THE PRAIRIE OF SACK ONLY IN
THE SINGLE DIGITS ALMOST TO THE NODAK BORDER. MODELS CONTINUE TO
HAVE SOME ISSUES WITH -SN FOR LATER MONDAY INTO TUESDAY...BUT THE
GENERAL TREND IS FOR A BIT SLOWER PROGRESSION OF PCPN ACROSS AREA
AS THE TROF NOW MOVING INTO THE PACIFIC NW MOVES THRU AREA.
CONTINUED WITH LIKELY POPS...BUT FAIRLY LOW QPF AS UPPER TROF
FEEDS ONLY ON COLD ADVECTION AS IT PROGRESSES THRU AREA. SHUD SEE
FAIRLY WDSPD SNOW IN THE HALF INCH TO PERHAPS ONE INCH
RANGE...MAYBE A LITTLE MORE IN SC. ALSO HELD ONTO -SN THRU TUESDAY
MORNING SE CWA WITH GFS/EC/NAM AND SREF ALL CONTINUING TO SPIT OUT
LGT PCPN.
FAST MOVING ZONAL FLOW BRINGS ANOTHER WAVE THRU ON WEDNESDAY AND
ANOTHER ON FRIDAY. WITH BAROCLINIC ZONE REMAINING ACROSS AREA THEY
SHUD BE ABLE TO WRING OUT SOME -SN. PLACEMENT WILL BE AN ISSUE WITH
GFS KEYING MORE ONTO BRINGING WED -SN MORE ACROSS CENTRAL CWA WITH
OTHER MODEL SOLUTIONS A BIT FARTHER NORTH. TEMPERATURES WILL ALSO
BE A CHALLENGE WITH THE PUSH-PULL OF ISOTHERMS ACROSS AREA AS
SYSTEMS MIGRATE THRU. COLDEST MORNING OF THE PERIOD WILL PROBABLY BE
THURSDAY WHEN HIGH PRESSURE BUILDS IN...BUT COLD WON`T LAST AS NEXT
PUSH OF VERY WARM AIR SURGES NORTH INTO THE AREA OVER THE WEEKEND.
&&
.AVIATION.../06Z TAF ISSUANCE/
STRATUS/FZDZ THAT WAS EXPECTED FOR WRN WI THIS EVENING HAS
DEVELOPED EAST OF EVEN EAU...SO HAVE ALL TERMINALS VFR THROUGH THE
REST OF THE NIGHT. AT THE SFC...FRONTAL FEATURE/TROUGH OVR AXN/RWF
NOW AND WILL BE WORKING EAST ACROSS THE TERMINALS TONIGHT. EXPCT
WINDS TO BE LGT AND VRB FOR A FEW HRS AS THE BOUNDARY
PASSES...BEFORE NW WINDS KICK UP BEHIND IT. ALREADY SEEING GUSTS
BEHIND THE FRONT ACROSS NODAK...AND WITH NAM BUFR SOUNDINGS
SHOWING MIX DOWN WINDS GETTING INTO THE 20S...CONTINUED TO GO A
BIT HIGHER THAN GFSLAMP FOR WIND SPEEDS. CONFIDENCE IN WHAT WILL
HAPPEN WITH COLD AIR STRATOCU MONDAY NOT VERY HIGH. SREF PROBS
WOULD INDICATE MUCH OF THE AREA WILL HAVE MVFR CIGS BY THE
AFTERNOON...BUT RH PROFILES FROM ALL TERMINALS SHOWING MOISTURE
BEING RATHER SHALLOW...SO LEFT LOWER CLOUD LAYER SCATTERED DURING
THE DAY UNTIL THERE IS MORE CONFIDENCE ON WHERE/WHEN/IF THEY WILL
OCCUR. -SN WILL BEGIN MOVING INTO WRN MN AROUND 00Z. BASED TIMING
INTO MN TERMINALS ON SREF/NAM/MPXWRF TIMING...WHICH ARE ALL
SIMILAR. THE -SN WILL CONTINUE FOR A FEW HRS BEYOND THIS PERIOD.
BESIDE THE SNOW...NNW WILL LIKELY NOT DIE DOWN MUCH MONDAY NIGHT.
KMSP...WINDS WILL BE LGT AND VRB FOR THE FIRST FEW HRS OF THE TAF
AS THE FRONT WORKS THROUGH. SKIES WILL REMAIN OVC...WITH CIGS
SLOWLY LOWERING THROUGH THE DAY. CONFIDENCE IN HOW POST FRONTAL
STRATOCU WILL UNFOLD NOT VERY HIGH...SO KEPT CONDITIONS VFR UNTIL
-SN BEGINS MOVING IN. BASED ON SREF PROBS FOR VIS LESS THAN
3SM...WINDOW WITH HIGHEST PROB FOR SNOW WILL BE FROM 06Z TO 15Z
MONDAY...WITH ACCUMS STILL LOOKING TO BE BETWEEN 1 AND 2 INCHES.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/MPG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
305 AM CST MON JAN 16 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
305 AM CST MON JAN 16 2012
MAIN FORECAST CONCERNS ARE ON FREEZING RAIN CHANCES THIS EVENING
AND THEN SNOW CHANCES AND AMOUNTS LATE TONIGHT THROUGH TUESDAY.
DATA ANALYSIS AS 00Z SHOWS MODELS WERE SEVERELY OVERDOING THE THE
LOW LEVEL SATURATION AS AREA RAOB SOUNDINGS WERE QUITE DRY...AND
TEMPERATURE DEW POINT SPREADS REMAINED IN THE 5 TO 6 DEGREE RANGE
THROUGHOUT LAST EVENING. THE 06Z SURFACE ANALYSIS SHOWS COLD FRONT
BISECTING MINNESOTA FROM NORTH TO SOUTH. SOUTHERLY FLOW AHEAD OF THE
FRONT HAS KEPT TEMPERATURES FROM FALLING OFF MUCH WITH READINGS IN
THE UPPER 20S TO AROUND 30. 11-3.9 MICRON SATELLITE IMAGERY AND
SURFACE REPORTS SHOWS HIGH CLOUDS ACROSS THE AREA...WITH THE ONLY
STRATUS BEING CONFINED TO NORTH CENTRAL WISCONSIN.
COLD FRONT WILL PUSH THROUGH THE FORECAST AREA EARLY THIS
MORNING...EXITING THE EASTERN COUNTIES BETWEEN 15Z-18Z. PRESSURE
GRADIENT WILL THEN TIGHTEN SOMEWHAT BEHIND THE FRONT AS COOLER AIR
SPILLS INTO THE AREA. DESPITE THE COLD ADVECTION...TEMPERATURES WILL
REBOUND A FEW DEGREES FROM CURRENT READINGS FOR HIGHS TODAY.
MEANWHILE A SURFACE LOW WILL BEGIN TO LIFT NORTHEAST OUT OF KANSAS
AND ALONG THE FRONTAL BOUNDARY. MOISTURE WITH THIS SHOULD REMAIN
SOUTH OF THE AREA THROUGH THE AFTERNOON HOURS...BUT WILL HAVE TO
WATCH FAR SOUTHWEST WISCONSIN FOR THE LATE AFTERNOON PERIOD.
FOR TONIGHT...SURFACE LOW CONTINUES PUSHING NORTHEAST AS SHORTWAVE
TROUGH ROTATES OUT INTO THE PLAINS. WILL SEE SOME MOISTURE PUSH INTO
SOUTHWEST WISCONSIN AND PARTS OF NORTHEAST IOWA DURING THE EVENING
HOURS. BUFKIT SOUNDINGS SHOW NO ICE PRESENT WITHIN THE CLOUD LAYER
AND WITH SUB FREEZING TEMPERATURES A FREEZING RAIN THREAT WILL BE
PRESENT. FOR NOW AREA SHOULD BE ON THE NORTHER FRINGE OF THE
PRECIPITATION SHIELD AND THUS ONLY HAVE LOW END PROBABILITIES...BUT
WILL HAVE TO BE WATCHED FOR SOME LIGHT ICING PROBLEMS.
MEANWHILE...TO THE NORTH A BAND OF SNOW WILL BEGIN TO PUSH INTO
MINNESOTA AHEAD OF THE APPROACHING SHORTWAVE AND THEN ACROSS THE
AREA TONIGHT. BUFKIT SOUNDS DO SATURATE ACROSS THE ENTIRE AND THUS ANY
PRECIPITATION AFTER 06Z LOOKS TO BE ALL SNOW. SWATH OF 700MB-
300MB QG CONVERGENCE AND 280K-290K LAYER ISENTROPIC LIFT ACCOMPANY
THE SHORTWAVE ACROSS THE AREA INTO TUESDAY MORNING BEFORE EXITING
EAST TUESDAY AFTERNOON. MODELS CONSISTENT IN 1 TO 2 INCHES OF SNOW
FOR MUCH OF THE AREA...WITH MOST OF THE ACCUMULATION COMING
BETWEEN 06Z-18Z TUESDAY.
BY TUESDAY NIGHT SURFACE RIDGE BUILDS QUICKLY INTO THE AREA...WITH
THE AXIS NEAR THE MISSISSIPPI RIVER BY 06Z. WITH CLEAR
SKIES...LIGHTS WIND AND SNOW COVER DID DROP LOWS BELOW GUIDANCE
VALUES...IN THE SINGLE DIGITS ABOVE AND BELOW ZERO.
FOR WEDNESDAY AND WEDNESDAY NIGHT MODELS DIVERGE WITH THE HANDLING
OF THE NEXT SHORTWAVE AND ASSOCIATED SURFACE LOW. GFS LOOKS TO BE
THE OUTLIER AS ITS TAKES A SURFACE LOW ACROSS THE FORECAST AREA. THE
16.00Z GEM/NAM AND ECMWF SOLUTIONS CLUSTERS THE SURFACE LOW TRACK
FURTHER NORTH ACROSS NORTHERN MINNESOTA INTO NORTHERN WISCONSIN.
THUS DID FOLLOW THE MORE NORTHERN SOLUTIONS...WITH LOW SNOW
PROBABILITIES ACROSS THE FAR NORTH WEDNESDAY AFTERNOON AND THEN A
LITTLE FURTHER SOUTH WEDNESDAY NIGHT AS THE COLD FRONT CROSSES THE
AREA.
.LONG TERM...THURSDAY THROUGH SUNDAY
305 AM CST MON JAN 16 2012
ARCTIC HIGH PRESSURE BUILDS IN ON THURSDAY...WITH 850MB TEMPERATURES
DROPPING TO NEAR -20 CELSIUS. EVEN WITH SOME SUN EXPECTED...HIGHS
WILL ONLY BE IN THE SINGLE DIGITS TO LOWER TEENS. THE HIGH SLIDES
OFF RATHER QUICKLY THURSDAY NIGHT WITH ANOTHER DISTURBANCE IN THE
NORTHWEST FLOW DROPPING OUT OF THE NORTHERN PLAINS INTO THE AREA FOR
FRIDAY. THIS COULD BRING A BAND OF SNOW TO THE AREA WITH THE ECMWF MORE
ROBUST...SUGGESTING SOME MINOR ACCUMULATIONS. UPPER FLOW THEN
BECOMES MORE ZONAL FOR THE WEEKEND A SOUTHERLY LOW LEVEL BEGINS TO PUSH
WARMER AIR TOWARDS THE REGION. TEMPERATURES MODERATE QUITE A BIT
SATURDAY AND SUNDAY WITH 850MB TEMPERATURES RISING BACK INTO THE
SINGLE DIGITS ABOVE ZERO AND THUS MAY PUSH SURFACE TEMPERATURES INTO THE
LOWER 40S FOR PARTS OF THE AREA BY SUNDAY.
&&
.AVIATION...THROUGH 06Z TUESDAY
1131 PM CST SUN JAN 15 2012
THE LOW CLOUDS THAT HAVE FORMED THIS EVENING HAVE REMAINED OVER
CENTRAL AND NORTHEAST WISCONSIN. THE 16.03Z RUC BUFKIT SOUNDINGS
NO LONGER SHOW SATURATION OCCURRING IN THE LOW LEVELS AT EITHER
TAF SITE AND HAVE PULLED ALL REMAINING MENTION OF ANY LOW CLOUDS.
ALSO REMOVED THE MVFR VISIBILITIES AS THE WINDS HAVE REMAINED UP
THIS EVENING TO KEEP THE LOW LEVELS MIXED AND NOT ALLOWING ANY FOG
TO FORM. THE WINDS WILL DIMINISH SOME OVERNIGHT AS THE FRONT
APPROACHES BUT THERE SHOULD STILL BE ENOUGH MIXING TO KEEP THE FOG
FROM FORMING. THE ONE EXCEPTION TO THIS MAY BE AT KLSE WHERE THE
WINDS MAY BECOME ALMOST CALM AND WITH A LITTLE EXTRA MOISTURE FROM
THE SNOW MELT TODAY SOME FOG COULD FORM LATE TONIGHT. SATELLITE
AND SURFACE OBSERVATIONS INDICATE THE MVFR CLOUD DECK THAT WAS
BEHIND THE FRONT EARLIER AS MOVE INTO CANADA AND JUST EXPECTING A
WIND SHIFT WITH SOME HIGH VFR CLOUDS ONCE THE FRONT COMES THROUGH
MONDAY MORNING. NO SIGNIFICANT CHANGE IN CONDITIONS IS THEN
EXPECTED TO OCCUR THROUGH THE REMAINDER OF THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 AM CST MON JAN 16 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1131 PM CST SUN JAN 15 2012
.SHORT TERM...
844 PM CST SUN JAN 15 2012
THE POSSIBILITY FOR FREEZING DRIZZLE TONIGHT APPEARS TO BE
DIMINISHING. THE 00Z KDVN SOUNDING WAS NOT SATURATED AT ALL IN THE
LOW LEVELS WHILE THE KGRB SOUNDING WAS MORE FAVORABLE. SATELLITE
AND SURFACE OBSERVATIONS SHOWING THE LOW STRATUS CLOUDS ARE
BEGINNING TO FORM OVER CENTRAL WISCONSIN WHERE THE LOW LEVEL
MOISTURE IS THE DEEPEST. LOOKING AT THE 00Z RUC BUFKIT SOUNDINGS
AND 00Z NAM PLAN VIEW DATA...IT NOW APPEARS THE ONLY PLACE WHERE
SATURATION MAY OCCUR IS IN THE I94 CORRIDOR AS THE RUC BUFKIT
SOUNDINGS STILL SATURATE KAUW AND TO A LESSER DEGREE KEAU. THE NAM
925 MB RH DATA CONFIRMS THIS AND ONLY HAS 90+ RH OVER CENTRAL INTO
NORTHEAST WISCONSIN. WILL UPDATE THE FORECAST TO REMOVE THE
FREEZING DRIZZLE FROM ALL BUT THE I94 CORRIDOR AND PUSH BACK THE
TIMING TO AFTER 05Z.
.LONG TERM...THURSDAY THROUGH SUNDAY
245 PM CST SUN JAN 15 2012
ECMWF...GFS AND GEM ALL FAVOR DRIVING AN UPPER LEVEL SHORTWAVE
TROUGH FROM THE PLAINS TO ACROSS THE MID MISSISSIPPI RIVER VALLEY
THU NIGHT-FRI. SOME DIFFERENCES IN PLACEMENT AND TIMING OF THIS
FEATURE...WITH THE EC THE QUICKER OF THE THREE. BOTH THE EC AND GFS
PRODUCE AN AREA OF PCPN NORTH OF THE MAIN PACKET OF ENERGY...AND
WOULD BRING THE POTENTIAL FOR A FEW INCHES OF ACCUMULATION TO THE
FORECAST AREA. THE GEM IS MORE ROBUST WITH A SHORTWAVE IN THE
NORTHERN STREAM...PRODUCING MORE QPF WITH IT AND LITTLE/IF ANY WITH
ITS PLAINS SHORTWAVE. LIKE THE CONSISTENCY OF THE GFS/EC FOR NOW AND
WILL CONTINUE WITH PCPN CHANCES IN THIS PERIOD. SOUTHERN FLOW
RETURNS FOR THE WEEKEND...AND AFTER A MID WEEK COOL DOWN...LOOK
FOR SEASONABLE TO MILD TEMPERATURES IN THIS PERIOD.
&&
.AVIATION...THROUGH 06Z TUESDAY
1131 PM CST SUN JAN 15 2012
THE LOW CLOUDS THAT HAVE FORMED THIS EVENING HAVE REMAINED OVER
CENTRAL AND NORTHEAST WISCONSIN. THE 16.03Z RUC BUFKIT SOUNDINGS
NO LONGER SHOW SATURATION OCCURRING IN THE LOW LEVELS AT EITHER
TAF SITE AND HAVE PULLED ALL REMAINING MENTION OF ANY LOW CLOUDS.
ALSO REMOVED THE MVFR VISIBILITIES AS THE WINDS HAVE REMAINED UP
THIS EVENING TO KEEP THE LOW LEVELS MIXED AND NOT ALLOWING ANY FOG
TO FORM. THE WINDS WILL DIMINISH SOME OVERNIGHT AS THE FRONT
APPROACHES BUT THERE SHOULD STILL BE ENOUGH MIXING TO KEEP THE FOG
FROM FORMING. THE ONE EXCEPTION TO THIS MAY BE AT KLSE WHERE THE
WINDS MAY BECOME ALMOST CALM AND WITH A LITTLE EXTRA MOISTURE FROM
THE SNOW MELT TODAY SOME FOG COULD FORM LATE TONIGHT. SATELLITE
AND SURFACE OBSERVATIONS INDICATE THE MVFR CLOUD DECK THAT WAS
BEHIND THE FRONT EARLIER AS MOVE INTO CANADA AND JUST EXPECTING A
WIND SHIFT WITH SOME HIGH VFR CLOUDS ONCE THE FRONT COMES THROUGH
MONDAY MORNING. NO SIGNIFICANT CHANGE IN CONDITIONS IS THEN
EXPECTED TO OCCUR THROUGH THE REMAINDER OF THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
245 PM CST SUN JAN 15 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
532 AM CST MON JAN 16 2012
.DISCUSSION...
TODAY THROUGH TUESDAY...A COLD FRONT PASSING THROUGH THE STATE
FROM W TO E THIS MORNING WILL BRING AN END TO THE BRIEF WARM-UP
FELT OVER THE WEEKEND FOR THE REGION. TEMPERATURES WILL GENERALLY
REMAIN STEADY OR FALL THROUGH THE DAY TDA AS WINDS SHIFT TO NW AND
BRING IN A REINFORCING SURGE OF COLDER AIR. THE FRONT WILL THEN
STALL OUT TO THE S AND E OF THE AREA OVERNIGHT INTO TUESDAY...BUT
THIS FRONT WILL ACT AS A PATHWAY FOR AN AREA OF LOW PRES
DEVELOPING OVER THE SOUTHERN PLAINS TO QUICKLY SHIFT NE TONIGHT
INTO TUE. IN CONJUNCTION WITH AN UPPER LEVEL SHORTWAVE TROUGH THAT
WILL SHIFT E THROUGH THE NRN PLAINS AND UPPER MISSISSIPPI RIVER
VALLEY TNGT INTO TUE...LIGHT SNOW IS EXPECTED FOR VIRTUALLY ALL OF
THE WFO MPX COVERAGE AREA...ESPECIALLY SOUTHERN PORTIONS. THE
SPEED OF THE SYSTEM ALONG WITH LACK OF MOISTURE /ONLY A FEW
HUNDREDTHS OF AN INCH QPF EXPECTED/ WILL MEAN LITTLE IN THE WAY OF
SNOWFALL IS EXPECTED...RANGING FROM AROUND 1/2 FOR CENTRAL MN TO 1
1/2 INCHES FOR SRN MN AND AROUND 1 INCH IN THE TWIN CITIES METRO
AND WRN WI. CONFIDENCE IS HIGH OF SEEING THESE MINOR SNOW
ACCUMULATIONS SO HAVE INCREASED POPS INTO THE LIKELY AND
CATEGORICAL RANGES FOR MUCH OF THE AREA. THE UPPER SHORTWAVE WILL
EJECT INTO THE GREAT LAKES DURING THE DAY ON TUE...BRINGING AN END
TO THE SNOWFALL. INCOMING SFC HIGH PRESSURE ALONG WITH UPPER LEVEL
RIDGING WILL MAKE FOR SOME PARTIAL CLEARING DURG THE DAY...BUT IT
WILL NOT BE MUCH AND ESPECIALLY NOT ENOUGH TO WARM TEMPERATURES
MUCH ABOVE 10 DEGREES FOR HIGHS ON TUE. IN ADDITION...BREEZY
CONDITIONS BEHIND THE FRONT FOR TONIGHT INTO TUESDAY WILL PUSH
WIND CHILL READINGS INTO THE 10 TO 20 DEGREES BELOW ZERO RANGE.
TUESDAY NIGHT THROUGH THURSDAY...HIGH PRES WILL SKIP THROUGH THE
REGION QUICKLY TUE NIGHT...FOLLOWED NEARLY AS QUICKLY BY A
CLIPPER-TYPE SYSTEM FOR WED. THE TRACK OF THIS LOW WILL MOVE IT
FROM SD ACRS SRN MN INTO SRN WI...MAKING THE ONLY POSSIBLE CHC FOR
LIGHT SNOW OVER CENTRAL MN INTO WRN WI. EVEN THEN...CHCS ARE NOT
THAT GREAT FOR ACCUMULATING SNOW. THIS SYSTEM QUICKLY MOVES INTO
THE GREAT LAKES WED NIGHT...FOLLOWED BY ANOTHER AREA OF COLD HIGH
PRES FOR THU WHICH WILL KEEP HIGH TEMPS ONLY IN THE SINGLE DIGITS
ABOVE ZERO WITH LOWS THU MRNG IN THE SINGLE DIGITS BELOW ZERO.
FRIDAY THROUGH SUNDAY...SLIGHTLY BETTER AGREEMENT IN THE WX
PATTERN FOR THE WEEKEND WITH THE TIMING OF AN ORGANIZED SYSTEM TO
PUSH THROUGH THE NRN PLAINS AND UPPER MISS RIVER VALLEY LATE SAT
THROUGH SUN. SYSTEM LOOKS TO BE DISPLACED FAR ENOUGH N OF THE WFO
MPX CWFA TO PRODUCE ANY MEANINGFUL PRECIP...AND ENOUGH WARM AIR
LOOKS TO BE BROUGHT NORTH AHEAD OF THE SYSTEM SUCH THAT A RETURN
OF WELL-ABOVE NORMAL TEMPERATURES IS LIKELY ALONG WITH A
PRECIPITATION REGIME THAT COULD BE A MIX OF RAIN AND SNOW AT
TIMES FOR LATE SUN OR SUN NIGHT. STILL PLENTY OF TIME TO RESOLVE
THE DETAILS OF THIS SYSTEM...BUT ATTM IT DOES NOT APPEAR TO BE
ANYTHING SIGNIFICANT.
&&
.AVIATION.../12Z TAF ISSUANCE/
SHORT TERM CONCERNS DEAL WITH DEVELOPING MVFR CIGS IN WC WI WHICH
IS PROGGED BY THE LATEST RUC TO INCREASE BY 15Z ACROSS ALL OF WC
WI...AND PORTIONS OF EC/SE MN. THIS WOULD AFFECT EAU/RNH...AND
POSSIBLY MSP. IN ADDITION...MVFR CIGS NEAR AXN WILL LIKELY PRODUCE
A TEMPORARY PERIOD OF MVFR CIGS BEFORE 16Z BASED ON UPSTREAM
CONDS. WNDS WILL REMAIN FROM THE NW/NNW OR DEVELOP AT RNH/EAU BY
15-18Z. SOME EARLY MORE BR SHOULD LIFT AT RNH/EAU BY 14Z.
NEXT AVIATION CONCERN DEALS WITH DEVELOPING MVFR/IFR CIGS/VSBYS IN
-SN AS A DISTURBANCE ACROSS THE NORTHERN ROCKIES MOVES EAST TOWARD
THE UPPER MIDWEST BY LATE IN THE DAY. CURRENT TAFS HAD A GOOD
HANDLE ON TIMING/CIGS/VSBYS AS THE -SN DEVELOPS. BASED ON
FORECAST RADAR...AXN WILL LIKELY SEE FLURRIES AFT 21Z...WITH
CIGS/VSBY LOWERING BY 00-02Z/17. ELSEWHERE...TIMING WILL BE 2 TO 4
HRS AFT AXN...WITH THE WORSE CONDS LIKELY AT RWF AS DEEPER
MOISTURE WILL RESIDE IN THE AREA. WNDS WILL CONTINUE FROM THE NNW
WITH SOME GUSTS EVEN DURING THE OVERNIGHT HRS ARND 18-22KTS.
MSP...MVFR CIGS TO THE NE OF THE AIRPORT SITE...OR ROUGHLY
40-60SM NE OF MSP...SHOULD HOLD IN THIS AREA. CONFIDENCE IS LOW
THESE CIGS WILL MOVE INTO MSP TAF AREA BY 14Z. SATELLITE TRENDS
NEED TO BE MONITORED FOR THIS SITUATION. NW/NNW WNDS ARND 12-14
KTS WITH GUSTS OF 18-22 KTS SHOULD CONTINUE THRU MOST OF THE TAF
PERIOD. AS -SN DEVELOPS THIS EVENING/OVERNIGHT...CIGS SHOULD
DECREASE TO MVFR WITH IFR CIGS/VSBYS LOOKING LIKELY AFT 6Z...WITH
THE WORSE CONDS BETWEEN 6-12Z. LATER SHIFTS CAN PIN POINT THE
BEST TIME FRAME WHERE IFR CIGS/VSBYS DEVELOP LATER TONIGHT. THE
-SN AND LOWER CIGS SHOULD BEGIN TO LIFT AFT 15Z/17.
TUE AFT 18Z...VFR
WED...MVFR -SN POSSIBLE.
THU...VFR
FRI...MVFR/IFR -SN POSSIBLE. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC/JLT
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
616 AM CST MON JAN 16 2012
.DISCUSSION...
/357 AM CST MON JAN 16 2012/
FOCUS IN THE SHORT TERM WILL BE SYSTEM TO AFFECT AREA TODAY AND
TONIGHT.
MDLS ARE IN GOOD AGREEMENT REGARDING MASS FIELDS WITH THIS SYSTEM.
THIS SYSTEM SEEMS TO BE MADE OF TWO FEATURES. ONE IS THE MAIN UPPER
TROF ACROSS THE PAC NW AND THE OTHER IS A S/W COMING ONSHORE THIS
MORNING OVER NRN BAJA. MDLS SUGGEST THESE TWO FEATURES CROSS THE
ROCKIES WITHOUT AMPLIFYING...AND ACTUALLY WEAKEN SOMEWHAT. WITH LACK
OF LEE CYCLOGENESIS...HAD SOME CONCERN THAT MDLS PROG SFC LOW TOO
FAR N. HOWEVER...LATEST SFC ANALYSIS DEPICTS SFC LOW DEVELOP OVER
CNTL KS AND SEE NO REASON THE LOW WILL MOVE FURTHER S THAN MDLS
SUGGEST.
MDLS CONTINUE TO SLOW PROGRESSION OF COLD AIR BEHIND THIS
SYSTEM...LIKELY DUE TO LOW AMPLIFIED TROF. THIS TREND SEEMS
REASONABLE AND HAVE ALSO SLOWED ONSET OF COLD AIR BOTH AT THE SFC AS
DEPICTED IN TEMPS TONIGHT/TOMORROW AND IN PRECIP TYPE.
FOR TODAY...HAVE TRENDED TEMPS AOA WARMEST GUIDANCE. WAS SOME
CONCERN THAT CLOUD COVER TODAY WUD KEEP TEMPS DOWN.
HOWEVER...STRATUS HAS BEEN SLOW TO MOVE N AND STARTING THE DAY IN
LOWER TO MID 40S...50S TO MID 60S SHUD BE ATTAINABLE.
AS FOR PRECIP...HAVE PUSHED POPS BACK TO LATE THIS AFTERNOON.
BELIEVE MUCH OF THE QPF SUGGESTED BY MDLS IS DUE TO CLOUD SCHEME
PRECIPITATING IN AREA OF STRATUS. SOUNDINGS SUGGEST STRONG WAA SHUD
HELP KEEP WARM SECTOR AIRMASS CAPPED UNTIL EARLY THIS EVENING. HAVE
ALSO MOVED MENTION OF TS FIGHTER N. BASED ON SHEAR AND THERMAL
PROFILES...CAN NOT RULE OUT POSSIBILITY OF TSRA PRODUCING STRONG
GUSTS AND/OR HAIL ACROSS EXTREME SRN PORTIONS OF THE CWA.
FURTHER N...CNTL AND NRN PORTIONS OF THE CWA...MDLS SUGGEST RA WILL
CHANGE TO SN AS COLD AIR MOVES IN BEHIND THE CDFNT. A SHORT PERIOD
OF SLEET IS POSSIBLE DURING THE TRANSITION...BUT SHUD BE SHORT
LIVED. MDLS SUGGEST LIGHT QPF AND THEREFORE HAVE ONLY MINOR
ACCUMULATIONS FCST FOR NOW. SOUNDINGS FOR PORTIONS OF CNTL MO
SUGGEST A LONGER PERIOD OF SLEET IS POSSIBLE...BUT HAVE LEFT AS SN
FOR NOW DUE TO LOW CONFIDENCE. IS SOME CONCERN THAT SOUNDINGS
SUGGEST PRECIP ENDING AS FZDZ ACROSS CNTL MO FOR LATE TONIGHT INTO
TUES MORNING. SOUNDS SUGGEST ICE CRYSTALS ARE LOST...HOWEVER...
BELIEVE THIS WILL BE THE END OF THE PRECIP AND HAVE NOT MENTIONED
FZDZ FOR NOW.
TEMPS ARE EXPECTED TO BRIEFLY FALL BACK BELOW SEASONAL AVG BEHIND
THIS CDFNT. MAX TEMP FOR TOMORROW WILL BE TEMP AT MIDNIGHT FOR MUCH
OF THE AREA WITH TEMPS CONTINUING TO FALL THRU THE DAY. TRENDED TWD
THE COOLEST GUIDANCE FOR TUES AND TUES NIGHT. WITH SWLY FLOW
EXPECTED ALREADY BY WED...HAVE TRENDED TWD THE WARMER GUIDANCE
AGAIN.
FOR THE EXTD...WITH A FOCUS ON THE SHORT TERM...MADE ONLY MINOR
CHANGES TO THE PREV FCST. OVERALL...TRENDED TEMPS TWD A BLEND OF
GUIDANCE AS MDLS ARE IN GOOD AGREEMENT THRU THE PERIOD. DID TREND
TWD THE COOLER GUIDANCE FOR SAT AS BELIEVE THE GFS IS TOO FAST WITH
THE RETREATING SFC RIDGE AND TRENDED TWD AOA WARMEST GUIDANCE FOR
TEMPS ON SUN AS AREA SHUD BE WITHIN AREA OF STRONG WAA.
TILLY
&&
.AVIATION...
/610 AM CST MON JAN 16 2012/
LOW LEVEL WIND SHEAR THREAT WILL CONTINUE THROUGH MID MORNING AS
DATA IS STILL INDICATING SW WIND AROUND 50 KTS BETWEEN 1500-2000
FT. OTHERWISE...OVERNIGHT SFC DATA CERTAINLY INDICATES LOW LEVEL MOISTURE
IS MAKING STRONG NWD PUSH BUT THE STRATUS THAT WAS EXPECTED TO
DEVELOP WITH THIS MOISTURE RETURN ISNT BEING NEARLY SO AGGRESSIVE
WITH ITS NWD SURGE. ALTHOUGH HIGHER CLOUDS ARE NOW MASKING EXTENT
AND LOCATION OF THE STRATUS IN THE LOW CLOUD ENHANCEMENT...EARLIER
ANIMATION AS WELL AS NEPHANALYSIS INDICATE THAT NWD ADVANCEMENT
HAS SLOWED/STALLED OVER AR OZARKS...ALTHOUGH HIGHER LEVEL SC HAS
WORKED ITS WAY UP THE MISSISSIPPI VALLEY INTO SE MO AND S IL.
FORECAST SOUNDINGS FROM ALL DATA SETS ARE ALL STRONGLY SUGGESTING
STRATUS SO PRIMARY QUESTION IS WHEN...AND FOR THIS TAF SET HAVE
USED LATEST RUC DATA TO DETERMINE ARRIVAL OF THE MVFR CIGS.
CERTAINLY LOOKS LIKE WARM FRONT WILL BE SETTING UP OVER N SECTIONS
OF THE FA AS LOW WORKS ENE FROM CNTRL KS INTO NW MO...AND WITH THE
VERY MOIST LOW LEVEL AMS ADVECTING INTO THE BOUNDARY IFR CIGS ARE
CERTAINLY A POSSIBILITY AT UIN. WITH ONLY SPOTTY PRECIP EXPECTED
TODAY...HAVE HELD OFF MENTION IN TAFS UNTIL TONIGHT WHEN COVERAGE
SHOULD BE MUCH GREATER.
SPECIFICS FOR KSTL...ALTHOUGH NO ACARS SOUNDINGS ARE AVAILABLE
ATTM...LATEST RUC SOUNDINGS FOR STL STILL INDICATING 50KTS IN THE
1500-2000 FT LEVEL SO HAVE CONTINUED LOW LEVEL WIND SHEAR THROUGH 15Z.
ALSO BASED ON RUC SOUNDINGS IT WOULD APPEAR THAT MVFR ST/SC SHOULD
ARRIVE IN THE AREA AROUND MIDDAY AND PERSIST THROUGHOUT THE
AFTERNOON/EVENING.
TRUETT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
538 AM CST MON JAN 16 2012
.UPDATE...
.AVIATION...
THE AREA OF MVFR CIGS ACROSS NERN WY/SRN MT IS EXPECTED TO
TRANSLATE SLOWLY SOUTH AND EAST TODAY INTO NWRN NEB LATE THIS
MORNING OR EARLY THIS AFTERNOON. THE RUC AND CURRENT SFC OBS
ALSO SUGGEST MVFR CIGS WILL FORM DIRECTLY OVER NRN PORTIONS OF
THE FCST AREA AND THEN SPREAD SOUTHWARD THIS AFTERNOON.
SNOW WITH IFR CIGS/VSBY IS EXPECTED TO DEVELOP IN SIMILAR FASHION
AS AN UPPER LEVEL DISTURBANCE OVER SCNTL MT MOVES THROUGH THE FCST
AREA LATER TODAY AND TONIGHT. THUS A TRANSITION FROM VFR TO MVFR
TO IFR IS EXPECTED WITH IFR COVERAGE HIGHEST ACROSS NRN NEB AS THE
DISTURBANCE MOVES THROUGH. MVFR/VFR CONDITIONS COULD DEVELOP FROM
WEST TO EAST AS THE DISTURBANCE DEPARTS FROM ROUGHLY 06Z ONWARD TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 356 AM CST MON JAN 16 2012/
SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
FORECAST CONCERNS THROUGH THIS PERIOD DEAL WITH SNOW CHANCES
TODAY AND TEMPERATURES THROUGH THE PERIOD.
AT 08Z...WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH MOVING
INLAND FROM THE PACIFIC NORTHWEST WITH SOME WEAK RIDGING INTO THE
PLAINS AND A RATHER ROBUST SHORTWAVE TROUGH MOVING ACROSS WESTERN
ONTARIO. AT THE SURFACE...A COLD FRONT ASSOCIATED WITH THE ONTARIO
SHORTWAVE HAD PUSHED ACROSS THE NEBRASKA THROUGH THE OVERNIGHT
HOURS ALLOWING FOR HIGH PRESSURE TO BUILD IN FROM THE NORTHWEST.
WINDS WERE BREEZY BEHIND THE COLD FRONT AND CLOUDS INCREASED SO
TEMPERATURES HAVEN/T EXHIBITED MUCH OF A DROP YET. DO HAVE TO LOOK
FURTHER UPSTREAM INTO SOUTH DAKOTA/NORTH DAKOTA AND MONTANA TO SEE
A DROP IN TEMPERATURES AS THOSE LOCATIONS ARE NOW OBSERVING SINGLE
DIGITS. IN THE LOCAL AREA...TEMPERATURES AT 08Z...REMAINED IN THE
MID 20S TO LOW 30S.
THE COLD AIR OVER MONTANA AND THE DAKOTAS WILL SLOWLY COME SOUTH
INTO WESTERN AND NORTH CENTRAL NEBRASKA TODAY AND TONIGHT. THE
OPERATIONAL ECMWF SEEMS TO HAVE A GOOD HANDLE ON THIS TEMPERATURE
PROFILE KEEPING COLD AIR ADVECTION ACROSS THE AREA THROUGH
TONIGHT. THE 16.00Z KLBF SOUNDING SHOWED THE 850MB TEMPERATURE AT
14C...WHICH ACCORDING TO THE ECMWF WILL DROP BELOW 0C /-2C TO -3C/
BY 12Z THIS MORNING...THEN TO -13C BY 12Z TUESDAY.
AS THE COLDER AIR IS IN PLACE...THE SHORTWAVE TROUGH OVER THE
PACIFIC NORTHWEST WILL CROSS THE ROCKY MOUNTAINS TODAY. ALTHOUGH
MOISTURE ISN/T TERRIBLY ABUNDANT AHEAD OF THIS SYSTEM...THE NAM
DOES SHOW PRECIPITABLE WATER OF AROUND 100 TO 120 PERCENT OF
NORMAL OVER THE FORECAST AREA AS THE PRIMARY LIFT FROM THE
SHORTWAVE PASSES BY. ASIDE FROM THE LARGE SCALE LIFT THERE IS A
BIT OF FRONTOGENESIS SHOWING UP /MAINLY IN THE 17.00Z TO 17.06Z
TIME FRAME/ SO IT DOES APPEAR THAT THERE WILL BE SUFFICIENT LIFT
TO SUPPORT THE DEVELOPMENT OF PRECIPITATION AND HAVE ADJUSTED
PRECIPITATION CHANCES ACCORDINGLY. TIMING HAS BEEN SLOWED A BIT...AS
SOUNDINGS AND CROSS SECTIONS FROM ALL MODELS SHOWING SATURATION
WILL NOT OCCUR UNTIL AFTERNOON AND PERHAPS EVENING ACROSS THE
SOUTHEAST HALF OF THE FORECAST AREA. DID KEEP A SLIGHT CHANCE FOR
SNOW IN DURING THE MORNING HOURS OVER NORTHERN SHERIDAN
COUNTY...BUT A DRY FORECAST FOR THE REMAINDER OF THE AREA THROUGH
NOON TODAY. ALSO...BUFKIT FORECAST SOUNDINGS FROM THE NAM AT KVTN
SHOW A DEEP...SATURATED...AND NEARLY ISOTHERMAL LAYER IN THE
DENDRITIC LAYER FROM JUST ABOVE THE SURFACE TO AROUND 700MB.
ALTHOUGH ACTUAL QPF VALUES SHOULD NOT BE SIGNIFICANT....0.10 TO
0.20 INCHES AT THE MOST...THE RATIOS SHOULD BE PRETTY HIGH SO USED
A 17:1 RATIO TO DEVELOP THE SNOWFALL AMOUNTS. CAME UP WITH 1 TO 3
INCHES OF SNOW ACROSS MUCH OF THE FORECAST AREA.
BEHIND THIS SHORTWAVE TROUGH...SHOULD GET SUBSIDENCE INTO THE AREA
ALLOWING FOR SKIES TO CLEAR TONIGHT. THE FAR NORTHWEST AND WESTERN
AREAS MAY EVEN SEE THE CLOUDS GONE BY EARLY TUESDAY MORNING. IF
THIS IS THE CASE...LOW TEMPERATURES TUESDAY MORNING OVER THE
PANHANDLE WILL BE QUITE CHILLY. WITH THE ANTICIPATED NEW SNOW-
COVER AND A COLD AIRMASS OVERHEAD...SOME LOCATIONS MAY STAY BELOW
ZERO /F/ OVERNIGHT.
WARM AIR ADVECTION AND RIDGING WILL BE BUILDING ALOFT ON
TUESDAY..BUT WITH HIGH PRESSURE OVERHEAD SLOW TO MOVE OUT...MAY
NOT GET MUCH RETURN FLOW. JUST FOR A REFERENCE...850MB
TEMPERATURES WILL STILL BE COLDER AT 18.00Z WITH VALUES FROM -10C
TO -4C. ALTHOUGH DON/T EXPECT MUCH FOR CLOUD COVER...WITH THE
EXPECTED NEW SNOW ON THE GROUND...DON/T THINK TEMPERATURES WILL
WARM UP TOO MUCH. THE MAJORITY OF THE AREA SHOULD SEE HIGHS REMAIN
BELOW FREEZING.
ANOTHER COLD FRONT WILL MOVE ACROSS NEBRASKA ON WEDNESDAY NIGHT.
THIS SHOULD BE A DRY FRONTAL PASSAGE WITH VERY LITTLE MOISTURE
ASSOCIATED WITH IT. BUT THIS FRONT WILL BRING DOWN MORE COLDER
AIR. THE ABNORMALLY COLD AIR /-18C TO -25C/ LOOKS TO STAY OVER THE
DAKOTAS BUT WILL STILL SEE A GOOD GRADIENT IN TEMPERATURES ACROSS
THE FORECAST AREA. LOOKING FOR HIGHS WEDNESDAY RANGING FROM AROUND
20 IN THE NORTHEAST TO AROUND 50 IN THE SOUTHWEST.
LONG TERM...THURSDAY THROUGH SUNDAY
THERE IS NOT GREAT AGREEMENT BETWEEN MODELS THROUGH THIS
PERIOD. ON THURSDAY...HIGH PRESSURE WILL BUILD INTO THE PLAINS
FROM THE NORTHEAST. THIS WILL PUSH THE COLD FRONT THAT MOVED
THROUGH WEDNESDAY NIGHT FURTHER TO THE SOUTH. LOW LEVEL MOISTURE
LOOKS TO CONVERGE ALONG AND NORTH OF THIS BOUNDARY...SO DO EXPECT
QUITE A BIT OF CLOUD COVER THURSDAY. MODEL SOLUTIONS KEEP THE
LOCAL AREA DRY...WITH ANY PRECIPITATION ALONG THIS BOUNDARY
STAYING INTO SOUTH DAKOTA. AS THE HIGH MOVES OFF TO THE EAST AND
SOUTHERLY FLOW RETURNS AS LOW PRESSURE DEVELOPS ON THE LEE SIDE OF
THE ROCKIES THERE DOES LOOK TO BE ENOUGH MOISTURE AND LIFT FOR
PRECIPITATION TO DEVELOP /AGAIN...MAINLY OVER SOUTH DAKOTA/. DID
KEEP IN THE SLIGHT CHANCES FOR PRECIPITATION OVER THE FAR
NORTHEASTERN PARTS OF THE FORECAST AREA AS THAT APPEARS TO BE THE
MOST LIKELY AREA TO RECEIVE PRECIPITATION...BUT DON/T HAVE MUCH
CONFIDENCE IN THAT. THE MODELS DIVERGE FURTHER INTO THE SECOND
PART OF NEXT WEEKEND WITH THE PASSAGE OF ANOTHER COLD FRONT. THE
ECMWF DOES INDICATE SOME PRECIPITATION WITH THE FRONT ON SUNDAY SO
DO HAVE A SLIGHT CHANCE FOR SNOW THROUGH THAT TIME PERIOD ALTHOUGH
LOW CONFIDENCE IN THAT OUTCOME.
IN TERMS OF TEMPERATURES THROUGH THIS PERIOD...RIDGING ALOFT
BUILDS IN FOR THE WEEKEND SO THERE WILL BE A WARMING TREND BEYOND
THURSDAY. WILL STILL SEE A GOOD GRADIENT FROM SOUTHWEST TO
NORTHEAST THURSDAY AND FRIDAY...BUT SHOULD GET MORE UNIFORM
WARMING BY SATURDAY AND SUNDAY. SATURDAY CURRENTLY LOOKS TO BE THE
WARMEST DAY OF THE BUNCH...WITH STRONG WARM AIR ADVECTION AHEAD OF
THE COLD FRONT SET TO PASS BY ON SUNDAY. THE ECMWF DOES BRING
850MB TEMPERATURES BACK UP TO 14C FOR SATURDAY AFTERNOON SO AGAIN
COULD BE PUSHING INTO THE 60S.
HYDROLOGY...
COLD TEMPERATURES OVER THE NEXT SEVERAL DAYS WILL CONTINUE THE ICE
JAMMING PROBLEM ALONG PORTIONS OF THE NORTH PLATTE RIVER. WILL NOT
EXPECT TO SEE IMPROVEMENT IN THIS SITUATION UNTIL POSSIBLY LATER
IN THE WEEK. THEREFORE EXPECT THE FLOODING TO CONTINUE IN THE AREA
FROM LEWELLEN TO LAKE MCCONAUGHY.
AVIATION...
THE AREA OF MVFR CIGS ACROSS NERN WY/SRN MT IS EXPECTED TO TRANSLATE
SLOWLY SOUTH AND EAST TODAY INTO NWRN NEB LATE THIS MORNING OR EARLY
THIS AFTERNOON...THEN THROUGH THE REMAINDER OF THE FCST AREA
TONIGHT.
SNOW WITH IFR CIGS/VSBY IS EXPECTED TO DEVELOP IN SIMILAR FASHION AS
AN UPPER LEVEL DISTURBANCE OVER SCNTL MT MOVES THROUGH THE FCST AREA
TODAY AND TONIGHT. THUS A TRANSITION FROM VFR TO MVFR TO IFR IS
EXPECTED WITH IFR COVERAGE HIGHEST ACROSS NRN NEB. MVFR/VFR
CONDITIONS COULD DEVELOP FROM WEST TO EAST AS THE DISTURBANCE
DEPARTS AFTER 06Z TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS DENVER CO
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 FOR THE
MOUNTAINS...FOOTHILLS AND ADJACENT PLAINS..ZONES 33>36..38>39 FROM
07Z TUESDAY NIGHT THROUGH 19Z THURSDAY AM.
&&
$$
BAKER/ENTREKIN
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
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..
&&
.AVIATION...
CONDITIONS ARE EXPECTED TO GRADUALLY DETERIORATE BY LATE THIS
THIS EVENING AS COLD FRONT MOVES THROUGH THE REGION. MVFR TO IFR
CIGS SHOULD COVER MOST OF THE AREA BY MID EVENING. SOME PATCHY
DRIZZLE AND FOG WILL MAY ALSO DEVELOP DURING THE SAME TIME PERIOD.
BY LATE EVENING SNOW IS EXPECTED TO DEVELOP OVER THE AREA. THERE
MAY BE A BRIEF PERIOD OF FREEZING RAIN FROM THE I80 CORRIDOR SOUTH
IN WEST CENTRAL IL AND ADJACENT AREAS OF SOUTHEAST IOWA INCLUDING
KMLI AND KBRL BEFORE THE PRECIP CHANGES TO ALL SNOW. THE SNOW IS
EXPECTED TO TAPER OFF BY LATE TONIGHT OR EARLY TUESDAY MORNING.
SOME ACCUMULATIONS POSSIBLE AT KCID/KMLI/KDBQ. NORTHWEST WINDS
WILL BE INCREASING OVER THE AREA OVERNIGHT WITH GUSTS OF 25KT TO
30KTS EXPECTED BY LATE TUESDAY MORNING. THE STRONG WINDS COULD
CAUSE SOME MVFR VSBYS IN BLOWING AND DRIFTING SNOW ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
DLF/12
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
433 PM EST MON JAN 16 2012
.SYNOPSIS...
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/...
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 18Z TAF ISSUANCE/...
EVEN THOUGH A FEW BREAKS IN THE SC MAY DVLP THIS AFTN...EXPECT MVFR
CONDITIONS TO PREVAIL INTO THIS EVNG ASSOCIATED WITH INCOMING COLD
FROPA. AS COLDER AIR BLOWS OVER THE RELATIVELY WARM WATERS OF LK SUP
TNGT...SHSN WL DVLP...ESPECIALLY WHEN DEEPER MSTR ASSOCIATED WITH
INCOMING UPR DISTURBANCE ARRIVES LATER. CONDITIONS SHOULD
DETERIORATE TO IFR THEN...WITH THE BEST CHC FOR LIFR LATE TNGT/TUE
MRNG AT IWD...WHERE OVERWATER INSTABILITY WL BE MAXIMIZED IN THE
PRESENCE OF FAVORABLE/CONFLUENT UPSLOPE N WIND.
&&
.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...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS BUFFALO NY
427 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 /22Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL DETERIORATE FAIRLY RAPIDLY FROM WEST TO EAST AS
A ABUNDANT LOW AND MID LEVEL MOISTURE MOVES INTO THE REGION. THIS
WILL BRING A MIX OF LIGHT RAIN OR FREEZING PRECIPITATION IN
SHELTERED VALLEYS AS WELL AS AREAS EAST OF LAKE ONTARIO /KJHW AND
KART/ WITH PLAIN BUT INTERMITTENT RAIN OR DRIZZLE TO MOST OF WESTERN
NY /KIAG-KBUF-KROC/. 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 LLJ BETWEEN 1K AND 2K FEET
TODAY WILL CONTINUE WITH LLWS 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...LAKE EFFECT SNOW WATCH FROM LATE TUESDAY NIGHT THROUGH
WEDNESDAY AFTERNOON FOR NYZ006>008.
WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR NYZ005-006.
LAKE EFFECT SNOW WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR NYZ019-020-085.
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...ZAFF
MARINE...ZAFF
AREA FORECAST DISCUSSION
NWS BUFFALO NY
420 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/...
ANOTHER DEEP STORM SYSTEM WILL PLOW ACROSS THE LOWER GREAT LAKES AT
THE START OF THIS PERIOD AND THIS WILL SLAM THE BRAKES ON OUR WARM
UP AS TEMPERATURES WILL PLUNGE BACK TO BELOW NORMAL LEVELS. THE
ABRUPT TRANSITION BACK TO WINTER WILL BE ACCOMPANIED BY ANOTHER
ROUND OF STRONG GUSTY WINDS ALONG WITH RENEWED LAKE SNOWS.
THE MAKINGS OF THE UPCOMING STORM SYSTEM CAN BE FOUND ON WV IMAGERY
EARLY THIS MORNING AS AN IMPRESSIVELY LARGE SHORTWAVE CAN BE SEEN
DIVING ACROSS THE PACIFIC NORTHWEST. THIS FEATURE WILL CRUISE OVER
THE ROCKIES DURING THE NEXT 12-24 HOURS BEFORE IT EMERGES OVER THE
CENTRAL PLAINS AT THE START OF THIS SHORT TERM PERIOD. THE VIGOROUS
SHORTWAVE WILL ENERGIZE A DEVELOPING SFC CYCLONE OVER THE MID
WEST...HELPING IT TO DEEPEN SOME 10MB IN 12 HOURS FROM ARND 1000MB
TUESDAY MORNING TO 990MB BY TUESDAY EVENING.
MODERATELY STRONG WARM ADVECTION IN ADVANCE OF THIS STRENGTHENING
SFC LOW ON TUESDAY WILL COMBINE WITH THE DYNAMICS FROM A COUPLED H25
JET TO GENERATE DEEP LIFT ACROSS OUR REGION. WHILE THERE MAY BE SOME
LEFTOVER LIGHT MIXED PCPN EAST OF LK ONTARIO EARLY TUESDAY MORNING...
WARM ADVECTION AT ALL LEVELS WILL SUPPORT FAIRLY WIDESPREAD RAIN.
QPF AMOUNTS WILL NOT BE IMPRESSIVE THOUGH...AS THE BEST OVERRUNNING
SURFACE (TIGHTEST BAROLCLINIC ZONE) WILL BE TO OUR NORTH. BASIN
AVERAGE RAINFALL AMOUNTS SHOULD BE UNDER A QUARTER INCH.
THE TRACK OF THE STRENGTHENING SFC LOW WILL BE TO THE WEST AND NORTH
OF THE FORECAST AREA...AND WHILE THIS WILL INITIALLY TRANSLATE INTO
A `WARM` EVENT FOR THE REGION...IT ALSO MEANS THAT WE WILL
EXPERIENCE ANOTHER ROUND OF STRONG GUSTY WINDS. THE LOW WILL MOVE
FROM ABOUT DTW TO YYZ DURING THE COURSE OF TUESDAY MORNING BEFORE
MAKING ITS WAY TO THE KINGSTON AREA TUESDAY EVENING. THIS IS THE
CLIMATOLOGICALLY FAVORED COURSE TO PRODUCE STRONG WINDS FROM LAKE
ERIE TO THE BUF-ROC-ART CORRIDOR...PARTLY DUE TO THE FUNNELING OF
THE WINDS UP THE LENGTH OF LAKE ERIE. THIS WILL ALSO PRODUCE A 3 TO
5 FOOT SEICHE ON LAKE ERIE TUESDAY EVENING WHEN IT WILL BE QUITE
STORMY ACROSS THE FORECAST AREA. THESE LEVELS WOULD NOT REQUIRE ANY
`FLAGS`.
BY TUESDAY EVENING...THE POWERFUL STORM SYSTEM WILL BE CENTERED JUST
NORTH OF LAKE ONTARIO AND THE STAGE WILL BE SET FOR STRONG WINDS TO
BUFFET THE REGION. STRONG COLD ADVECTION AND THE SUGGESTION OF A
STRATOSPHERIC INTRUSION IN THE WAKE OF THE PASSING STORM WILL
MAXIMIZE THE 40KT LOW LEVEL WINDS...WITH A TIGHT SFC PRESSURE
GRADIENT AND 5MB/HR ISALLOBARIC PRESSURE RISES SUPPORTING SFC WIND
GUSTS IN EXCESS OF 40 MPH. A WIND ADVISORY MAY BE NEEDED...
PARTICULARLY ALONG THE LAKE ERIE SHORE/IAG FRONTIER TO ROC.
ALONG WITH THE STRONG WINDS...THE PASSAGE OF AN ASSOCIATED COLD
FRONT WILL USHER IN THE NEXT BLAST OF WINTRY TEMPERATURES AS MERCURY
READINGS WILL TUMBLE OUT OF THE 40S TUESDAY EVENING INTO THE TEENS
AND 20S OVERNIGHT. THIS COULD LEAD TO SOME ICY SURFACES AS OUR PCPN
WILL QUICKLY CHANGE FROM RAIN TO SNOW...AND THEN TO LAKE DRIVEN
SNOW. ALL AREAS SHOULD PICK UP AT LEAST AN INCH OR TWO OF WIND
DRIVEN SYNOPTIC SNOW EARLY TUESDAY NIGHT...WITH THE SNOW BECOMING
CONCENTRATED SOUTHEAST OF BOTH LAKES AFTER MIDNIGHT AS H85 TEMPS OF
-12 TO -16C WILL ONCE AGAIN START UP THE LAKE EFFECT SNOW MACHINE.
AS STATED IN PREVIOUS DISCUSSIONS...WILL INCLUDE THE MENTION OF
BLOWING SNOW AS WELL. AS A RESULT OF THIS HIGH PROBABILITY
SCENARIO...WINTER WEATHER ADVISORIES WILL LIKELY BE NEEDED FOR THE
REGION WITH POSSIBLE LAKE EFFECT HEADLINES FOR THE SNOWBELTS
SOUTHEAST OF THE LAKES.
ON WEDNESDAY...THE STILL INTENSIFYING STORM SYSTEM WILL LIFT
NORTHEAST ACROSS THE ST LAWRENCE VALLEY WHILE A FAST MOVING BUT
NARROW RIDGE WILL TRAVERSE THE GREAT LAKES REGION. WHILE THIS WILL
ENCOURAGE LARGE SCALE SUBSIDENCE ACROSS WESTERN NEW YORK...H85 TEMPS
OF -17C AND FAVORABLY HIGH A CAP OF ABOUT 10K FT WILL KEEP PROMOTE
MORE LAKE SNOW SOUTHEAST OF BOTH LAKES. IN FACT...WILL BE RAISING
OUR POPS FOR THESE AREAS BY AT LEAST 10 POINTS. OTHERWISE...WE CAN
EXPECT A PARTLY SUNNY AND COLD DAY WITH DIMINISHING WINDS.
AS THE RIDGE MOVES ACROSS OUR REGION WEDNESDAY NIGHT...THE ONSET OF
WARM ADVECTION WILL LOWER AN INCREASINGLY STRONGER CAP...WHICH IN
TURN WILL WEAKEN THE LAKE SNOWS. THIS WEAKENING ACTIVITY OFF BOTH
LAKES WILL LIFT NORTH DURING THE COURSE OF THE NIGHT...POTENTIALLY
BRINGING A COATING TO AN INCH OR SO OF FLUFF TO THE BUF/ART METRO
AREAS.
ANOTHER AREA OF LOW PRESSURE WILL CROSS JUST NORTH OF THE GREAT
LAKES ON THURSDAY. FOR WHAT ITS WORTH...WILL ACCEPT THE TRACK
OFFERED UP BY THE ECMWF AND SREF AS THE GFS AGAIN LOOKS LIKE THE
OUTLIER IN ITS MORE SOUTHERN TRACK. THE WARM ADVECTION AHEAD OF THIS
FEATURE WILL PRODUCE PLENTY OF CLOUDS ACROSS OUR REGION WITH SOME
SNOW SHOWERS BECOMING LIKELY DURING THE COURSE OF THE DAY.
AS THIS NEXT STORM SYSTEM RACES ACROSS EASTERN ONTARIO TO QUEBEC
THURSDAY NIGHT...ITS AFFILIATED COLD FRONT WILL SWEEP ACROSS OUR
FORECAST AREA TO USHER IN THE NEXT ROUND OF VERY COLD AIR. THIS WILL
PRODUCE MORE SNOW SHOWERS FOR THE REGION WITH SHORT LIVED LAKE SNOWS
ANTICIPATED ONCE AGAIN FOR THE SNOWBELTS SOUTHEAST OF THE LAKES.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
WINTER WILL GIVE WAY TO DRAMATICALLY MILDER CONDITIONS DURING THIS
PERIOD...AND WITHOUT MUCH OF A FIGHT. A RELATIVELY LOW AMPLITUDE
PATTERN...DOMINATED UP TO THIS POINT BY THE NORTHERN BRANCH OF THE
JET...WILL SURRENDER TO A WARM PACIFIC FLOW THAT WILL FLOOD THE
ENTIRE COUNTRY. THIS WILL LEAD TO MUCH ABOVE NORMAL TEMPERATURES.
SOME DETAILS...
FOR FRIDAY HIGH PRESSURE FROM CANADA POKES SOUTHWARD ACROSS THE
EASTERN GREAT LAKES WITH A FRESH ARCTIC AIRMASS CROSSING THE LAKE
WATERS. THE 12Z GFS IS COLDER THAN THE 12Z ECMWF WITH TEMPERATURES
AT 850 HPA CLOSE TO -15 TO -20C ACROSS THE REGION...WHILE THE ECMWF
IS SEVERAL DEGREES COLDER. WILL LOWER TEMPERATURES AT THE SURFACE
THROUGH THE DAY FRIDAY AND FRIDAY NIGHT BY SEVERAL DEGREES FROM
CONTINUITY...WHILE MAINTAINING THE LAKE SNOW CHCS DOWNWIND OF THE
LAKES ON ANOTHER NORTHWEST FLOW. TEMPERATURES FOR LOWS FRIDAY NIGHT
ARE STILL UNCERTAIN ESPECIALLY ACROSS THE NORTH COUNTRY WHERE
OVERNIGHT LOWS MAY BE MUCH LOWER THAN CURRENT FORECAST.
THE WEEKEND BEGINS WITH SNOW/RAIN CHCS AS ANOTHER SFC LOW FORMS ON
THE LEE OF THE ROCKIES IN SOUTHERN CANADA AND TRACKS EASTWARD ACROSS
THE SOUTHERN CANADIAN PROVINCES. WITH THIS LOW TRACKING FURTHER TO
THE NORTH THAN THE THURSDAY LOW...INCREASING CHCS FOR RAIN TO MIX IN
WITH THIS SYSTEM....ESPECIALLY ON SUNDAY AS SFC TEMPERATURES MAY
RISE INTO THE 40S...TO NEAR 50 AS A STRONG...MILD SOUTHERLY FLOW
DEVELOPS. TEMPERATURES OF THIS MAGNITUDE WILL SUPPORT JUST PLAIN
RAIN SHOWERS THROUGH THE DAY ON SUNDAY...THOUGH WILL KEEP POPS LOW
CHC FOR THIS FAR OUT WITH MODEL UNCERTAINTY.
LOOKING FURTHER OUT TO THE FIRST FEW DAYS OF THE NEW WORK WEEK...
THERE IS STRONG CONSENSUS BETWEEN THE ECMWF AND GEFS THAT THE WARM
PACIFIC FLOW WILL REMAIN IN PLACE FOR MONDAY INTO TUESDAY. THIS
PATTERN WILL PROMOTE DAYTIME TEMPERATURES TO CLIMB WELL INTO THE
40S...WITH SOME 50S NOT OUT OF THE QUESTION FOR THE GENESEE VALLEY.
WHILE A FRONTAL PASSAGE WILL LIKELY KNOCK SOME STEAM OUT OF THIS
WARM UP FOR MID WEEK...THE OVERALL PATTERN SHOULD REMAIN VERY
PACIFIC IN NATURE FOR THE REST OF NEXT WEEK. THIS TREND IS SUPPORTED
BY THE 6 TO 10 AND 8 TO 14 DAY TEMP OUTLOOKS SUPPLIED BY THE CLIMATE
PREDICTION CENTER.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL DETERIORATE FAIRLY RAPIDLY FROM WEST TO EAST AS
A ABUNDANT LOW AND MID LEVEL MOISTURE MOVES INTO THE REGION. THIS
WILL BRING A MIX OF LIGHT RAIN OR FREEZING PRECIPITATION IN
SHELTERED VALLEYS AS WELL AS AREAS EAST OF LAKE ONTARIO /KJHW AND
KART/ WITH PLAIN BUT INTERMITTENT RAIN OR DRIZZLE TO MOST OF WESTERN
NY /KIAG-KBUF-KROC/. 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 LLJ BETWEEN 1K AND 2K FEET
TODAY WILL CONTINUE WITH LLWS 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...RSH
LONG TERM...RSH/THOMAS
AVIATION...ZAFF
MARINE...ZAFF
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1040 AM CST MON JAN 16 2012
.DISCUSSION...
THE INITIAL SURGE OF COLD ADVECTION IS NOW THROUGH THE FCST AREA.
MODEL FORECASTS INDICATE THE 850 MB COLD ADVECTION LESSENS THIS
AFTN-EVE THEN RETURNS OVERNIGHT AS SHORT WAVE PASSES BY TO OUR
SOUTH. THUS FEEL TEMPS LIKELY NOT FALL MUCH FURTHER TODAY AND MAY
RISE 1-2 DEGREES IN SOME AREAS. CLOUD COVER IS QUITE PATCHY WITH
AREAS OF STRATOCU...BUT THESE ARE QUITE THIN. HIGHER LEVEL CLOUDS
MOVING NORTHEAST ACROSS SOUTHEAST HALF OF NORTH DAKOTA INTO MN IN
ADVANCE OF SHORT WAVE IS QUITE THIN IN SPOTS TOO. THUS AREA SEEING
SOME SUN. DUE THIS TAPPERED BACK CLOUD COVER A BIT ESP IN
NORTHEAST NORTH DAKOTA.
PER ABR/BIS COORD...CUT BACK A BIT ON POPS IN FAR SE ND AND
DELAYED EASTWARD ADVANCE JUST A TAD. INCOMING RUC IS A BIT SLOWER
IN HAVING ANY PRECIP NOT REACHING FAR SE ND TIL NEARLY 00Z. GFS
MAINTAINS MOSTLY SOUTH OF US...WHICH MAKES SENCE DUE TO DRY
NORTHERLY WINDS MOVING IN. ECHOES WILL NEED TO FALL FROM MID
LEVELS SO EXPECT ONLY MINIMAL AMTS REACHING THE GROUND.
&&
.PREV DISCUSSION... /ISSUED 332 AM CST MON JAN 16 2012/
SHORT TERM...
TEMPERATURES AND CHANCES FOR LIGHT SNOW TODAY AND WEDNESDAY WILL
BE THE PRIMARY FORECAST PROBLEMS FOR THE SHORT TERM.
THE ARCTIC COLD FRONT HAS MOVED MOST OF THE WAY THROUGH THE
CWA...AND ALTHOUGH A COUPLE OF STATIONS ARE HANGING ONTO TEMPS IN
THE 20S...THE COLD AIR ADVECTION SHOULD ALLOW TEMPS TO DROP
SHORTLY. MOST GUIDANCE AND GOING FORECAST HAVE TEMPERATURES
FALLING THROUGHOUT THE DAY...AND THIS CONTINUES TO SEEM
REASONABLE. MADE A FEW MINOR TWEAKS FOR CURRENT TEMPS...BUT WILL
CONTINUE TO HAVE HIGHS SLOWLY FALLING INTO THE SINGLE DIGITS
ACROSS MOST OF THE CWA.
WV LOOP HAS A DECENT SHORTWAVE CURRENTLY OVER OR/ID THAT WILL MOVE
INTO WY TODAY. SFC LOW PRESSURE THIS AFTERNOON AND TONIGHT WILL BE
LOCATED WELL TO OUR SOUTH...BUT MODELS ARE BREAKING OUT A FAIR
AMOUNT OF PRECIP ALONG THE 700MB BAROCLINIC ZONE ON THE NORTHWEST
SIDE OF THE LOW AND BRING SOME OF IT INTO THE FAR SOUTHERN CWA.
DRY ARCTIC AIR COMING IN FROM THE NORTH WILL KEEP PRECIP FROM
MAKING IT TOO FAR INTO THE CWA...BUT OUR SOUTHERN COUNTIES COULD
GET BRUSHED WITH UP TO A HALF AN INCH OF SNOW THIS AFTERNOON AND
TONIGHT. BUMPED UP POPS TO AROUND 40 PERCENT IN THE FAR SOUTH.
WINDS WILL DECREASE MONDAY NIGHT AS THE CENTER OF THE SFC HIGH
MOVES BY JUST TO OUR WEST. TEMPS SHOULD FALL TO WELL BELOW ZERO
WITH SOME VALUES AROUND 10 BELOW IN THE NORTH. TUESDAY SHOULD
CONTINUE TO BE QUIET BUT COLD AS THE SFC HIGH PRESSURE CENTER
MOVES TO THE EAST.
A SHORTWAVE TROUGH MOVING FROM CANADA INTO ND TUESDAY NIGHT AND
WEDNESDAY WILL BRING THE NEXT CHANCE FOR SOME LIGHT SNOW. THE 00Z
GFS HAS BEEN MUCH FURTHER SOUTH WITH THE SYSTEM THAN THE 00Z
NAM...WHICH HAD THE SFC LOW OVER ND AND THE FRONTAL BOUNDARY ALONG
THE CANADIAN BORDER. THE ECMWF AND GEM WERE TRENDING TO A MORE
NORTHERLY SOLUTION...BUT THE 06Z NAM HAS GONE A BIT FURTHER TO THE
SOUTH. CURRENT FORECAST HAS 30 POPS ALONG THE NORTHERN COUNTIES
TUESDAY NIGHT AND THEN DROPPING INTO THE CENTRAL CWA DURING THE
DAY ON WEDNESDAY. EVEN THE MORE NORTHERLY SOLUTIONS WERE BREAKING
OUT SOME PRECIP AS A COLD FRONT DROPS DOWN ON WEDNESDAY. WITH ALL
THE UNCERTAINTY...SEE LITTLE REASON TO MAKE BIG CHANGES TO WHAT WE
HAVE GOING FOR NOW.
TEMPS COULD BE TRICKY LATE TUESDAY NIGHT AND WEDNESDAY AS SOME
WARM AIR ADVECTION SETS UP BEFORE THE NEXT COLD FRONT COMES
THROUGH. COULD SEE SOME NON-DIURNAL TEMPS...BUT A LITTLE EARLY TO
GO WITH THAT NOW AS THERE ARE A LOT OF MODEL DIFFERENCES IN TIMING
AND HOW FAR NORTH THEY BRING THE SFC LOW. DID BUMP UP HIGHS A BIT IN
THE FAR SOUTHERN COUNTIES ON WEDNESDAY AS EVEN THE SOUTHERN
SOLUTIONS HAVE SOME WARMING IN THAT AREA BEFORE COLD AIR COMES
RUSHING DOWN. WEDNESDAY NIGHT WILL BE VERY COLD AS THE CENTER OF
THE SFC HIGH MOVES DOWN INTO THE PLAINS. DECREASING WINDS AND
CLOUDS SHOULD ALLOW TEMPS TO GET INTO THE 10 TO 20 BELOW RANGE.
LONG TERM (THU-SUN)...
FOR THE EXTENDED PERIOD MODELS IN GOOD AGREEMENT AT THE BEGINNING OF
THE PERIOD AND TIMING DIFFERENCES BECOME APPARENT BY THE WEEKEND.
MODERATING TEMPS FOR THE END OF THE WEEK AS COLD POOL GETS SHUNTED
EAST WITH NW 500MB FLOW BREAKING DOWN INTO A MORE ZONAL DIRECTION.
SNOW CHANCES REMAIN FOR THE END OF THE WEEK AS MODELS CONTINUE TO
HAVE A POOR HANDLE ON BAROCLINIC ZONE ACROSS THE NORTHERN PLAINS AND
TIMING AND PLACEMENT OF WEAK SHORT WAVES. LIGHT ACCUMULATIONS IF ANY
SNOW FALL OCCURS.
AVIATION...
PATCHY STRATUS HAS CONTINUED TO MOVE DOWN FROM CANADA AND DROP TAF
SITES DOWN TO MVFR PERIODICALLY...ALTHOUGH THERE HAS BEEN NO
CONSISTENCY. WILL COVER WITH TEMPO GROUPS AS RESTRICTIONS TO
CEILINGS HAVE BEEN SHORT LIVED BEFORE GOING BACK TO VFR. MORE MID
LEVEL CLOUDS WILL MOVE IN AFTER 15Z OR SO...WITH CONDITIONS GOING
VFR UNDER 4000-8000 FT CEILINGS. WINDS WILL CONTINUE FROM THE
NORTHWEST AT AROUND 15 KTS WITH SOME GUSTS UP TO 25 KTS IN THE
AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/JR
AREA FORECAST DISCUSSION
NWS NORMAN OK
1148 AM CST MON JAN 16 2012
.AVIATION...
COLD FRONT WILL MOVE ACROSS ALL TERMINAL SITES LATER THIS EVENING
AND OVERNIGHT. FRONT/WIND SHIFT SHOULD REMAIN ALONG AND JUST NORTH
OF KANSAS/OK BORDER UNTIL A COUPLE OF SHORTWAVE TROUGHS MOVE
ACROSS THE SOUTHERN PLAINS THIS EVENING INTO THE OVERNIGHT. CIRRUS
HAS THINNED SOME ACROSS NORTHWEST OKLAHOMA WHICH WILL ALLOW FOR
BETTER MIXING AND HIGHER GUSTS THIS AFTERNOON. NOT MUCH IN THE WAY
OF LOW CLOUDS BEHIND FRONT IN KANSAS LATE THIS MORNING...BUT
COULD SEE SCATTERED LOW CLOUDS FORM BEHIND THE FRONT FOR A FEW
HOURS OVERNIGHT. LIFT ASSOCIATED WITH APPROACHING FRONT AND
SHORTWAVES MAY BE ENOUGH FOR ISOLATED/WIDELY SCATTERED SHOWERS...BUT
NOT ENOUGH COVERAGE TO MENTION IN NORTHERN TAFS AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 1039 AM CST MON JAN 16 2012/
DISCUSSION...
WITH PLENTY OF CIRRUS STREAMING OVER THE REGION LOWERED HIGHS A
LITTLE BIT...FOLLOWING CLOSELY TO LATEST RUC13 OUTPUT. THE RUC
ALSO APPEARS TO HAVE BEST HANDLE ON FRONT THAT HAS ALREADY MADE
ITS WAY INTO NORTHERN PARTS OF OKLAHOMA. ALTHOUGH 60S AND 70S WILL
BE WIDESPREAD...SOME PARTS OF NORTH-CENTRAL AND NORTHWEST OKLAHOMA
THAT BORDERS KANSAS WILL LIKELY STRUGGLE TO GET OUT OF MID 50S AND
ACTUALLY SEE TEMPS FALL LATE THIS AFTERNOON.
WILL LEAVE THE LOW POPS FOR THIS EVENING ACROSS NORTH-CENTRAL AND
CENTRAL PARTS OF OKLAHOMA AS MAIN S/WV APPROACHES AND FRONT WILL
BE IN VICINITY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 68 32 43 21 / 10 20 10 0
HOBART OK 70 31 44 20 / 0 10 0 0
WICHITA FALLS TX 71 39 49 22 / 10 10 10 0
GAGE OK 70 23 38 13 / 0 10 0 0
PONCA CITY OK 67 27 36 15 / 10 20 10 0
DURANT OK 69 42 50 26 / 10 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
1039 AM CST MON JAN 16 2012
.DISCUSSION...
WITH PLENTY OF CIRRUS STREAMING OVER THE REGION LOWERED HIGHS A
LITTLE BIT...FOLLOWING CLOSELY TO LATEST RUC13 OUTPUT. THE RUC
ALSO APPEARS TO HAVE BEST HANDLE ON FRONT THAT HAS ALREADY MADE
ITS WAY INTO NORTHERN PARTS OF OKLAHOMA. ALTHOUGH 60S AND 70S WILL
BE WIDESPREAD...SOME PARTS OF NORTH-CENTRAL AND NORTHWEST OKLAHOMA
THAT BORDERS KANSAS WILL LIKELY STRUGGLE TO GET OUT OF MID 50S AND
ACTUALLY SEE TEMPS FALL LATE THIS AFTERNOON.
WILL LEAVE THE LOW POPS FOR THIS EVENING ACROSS NORTH-CENTRAL AND
CENTRAL PARTS OF OKLAHOMA AS MAIN S/WV APPROACHES AND FRONT WILL
BE IN VICINITY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 68 32 43 21 / 10 20 10 0
HOBART OK 70 31 44 20 / 0 10 0 0
WICHITA FALLS TX 71 39 49 22 / 10 10 10 0
GAGE OK 70 23 38 13 / 0 10 0 0
PONCA CITY OK 67 27 36 15 / 10 20 10 0
DURANT OK 69 42 50 26 / 10 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
11/06
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1151 AM CST MON JAN 16 2012
.AVIATION...
FOR THE 18Z TAFS...STRONG WINDS AND POSSIBLE REDUCTION OF
VISIBILITIES DUE TO BLOWING DUST ARE THE MAIN CONCERNS AT ALL TAF
SITES THROUGH 03Z.
AT KAMA...STRONGEST WINDS WITH GUSTS NEAR 50 KT WILL OCCUR 20-24Z.
AIRPORT WEATHER WARNING REMAINS IN EFFECT UNTIL 24Z WHICH SEEMS TO BE
ON TRACK AS WINDS SHOULD DIMINISH BELOW 40 KT AFTER 00Z. THERE IS A
SMALL CHANCE BLOWING DUST COULD REDUCE CONDITIONS TO MVFR OR LOWER
20-24Z...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. COLD FRONT WILL
BRING WIND SHIFT TO THE NORTH 09-13Z WITH A SMALL CHANCE OF MVFR/IFR
CEILINGS 09-15Z.
FOR KDHT...THINK CONDITIONS WILL BE VERY SIMILAR TO KAMA WITH A
SLIGHTLY QUICKER ARRIVAL OF THE COLD FRONT AND NORTH WINDS.
FOR KGUY...SURFACE WINDS SHOULD REMAIN LIGHTER THROUGH 24Z COMPARED
TO KAMA AND KDHT. COLD FRONT SHOULD ARRIVE 05-09Z WITH SMALL CHANCE
OF MVFR/IFR CEILINGS 05-15Z.
MBS
&&
.PREV DISCUSSION... /ISSUED 1122 AM CST MON JAN 16 2012/
..WINDY TO VERY WINDY CONDITIONS EXPECTED ACROSS MUCH OF THE
PANHANDLES THIS AFTERNOON...
UPDATE...
ISSUED A HIGH WIND WARNING FOR THE WEST TEXAS PANHANDLE INCLUDING
AMARILLO...CANYON...HEREFORD...AND DALHART. EXPANDED WIND ADVISORY
EAST TO INCLUDE BOISE CITY...STRATFORD...BORGER...PAMPA...AND
CLARENDON.
INCREASED WINDS AND HIGHEST ACROSS THE AREA THIS AFTERNOON.
DISCUSSION...
UPGRADE TO A HIGH WIND WARNING FOR THE WEST TEXAS PANHANDLE THIS
AFTERNOON AS LATEST TUCUMCARI NM PROFILER INDICATED 45-55 KT 2-3 KM
MSL...ABOUT 3000-8000 FT AGL. HAVE MODERATE TO HIGH CONFIDENCE THAT
THESE WINDS WILL MIX DOWN TO THE SURFACE THIS AFTERNOON IN THE
WARNING AREA...PARTICULARLY IN THE 2 TO 6 PM TIME FRAME.
EXPANDED THE WIND ADVISORY FARTHER EAST AS WELL THINKING HIGHER WINDS
WILL MIX EASTWARD DURING THE AFTERNOON.
BLOWING DUST IS ANOTHER CONCERN THIS AFTERNOON DUE TO DRY SOILS AND
STRONG WINDS. WILL CONTINUE TO EVALUATE THROUGHOUT THE AFTERNOON.
THERE IS A SMALL CHANCE THAT A FEW THUNDERSTORMS COULD DEVELOP IN THE
2 TO 8 PM CST TIME FRAME ACROSS THE AREA AS LATEST RUC13 INDICATED
LIFTED INDICES 0 TO -2 AND UP TO 400 J/KG. CONVECTIVE TEMPERATURES IN
THE MID 60S TO LOWER 70S MAY BE REACHED. THESE STORMS COULD IGNITE
FIRES AND PRODUCE VERY LITTLE RAIN DUE TO HIGH CLOUD BASES. IN
ADDITION...VARIABLE WIND GUSTS COULD OCCUR. DUE TO LOW CONFIDENCE
ESPECIALLY IN REGARDS TO THE AMOUNT OF LOW LEVEL MOISTURE...KEPT
THUNDER MENTION OUT OF FORECAST FOR NOW.
INCREASED HIGHS SLIGHTLY AS WELL WITH A GOOD AMOUNT OF SUN EXPECTED.
CUMULUS CLOUDS WILL DEVELOP AND FILL IN LATER THIS AFTERNOON.
PRODUCTS HAVE BEEN UPDATED.
MBS
FIRE WEATHER...
WINDY TO VERY WINDY CONDITIONS WILL PREVAIL THIS AFTERNOON...THOUGH
RELATIVE HUMIDITY LEVELS SHOULD STAY ABOVE 20 PERCENT.
THERE IS A SMALL CHANCE FOR DRY LIGHTNING BETWEEN 2 AND 8 PM CST THIS
AFTERNOON WHICH COULD IGNITE FIRES.
MBS
PREV DISCUSSION... /ISSUED 525 AM CST MON JAN 16 2012/
AVIATION...
FOR THE 12Z KAMA TAF...VFR CONDITIONS WILL CONTINUE UNTIL THE FRONT
MOVES THROUGH...AND ARE LIKELY EVEN AFTER THE COLD FRONT ARRIVES. AS
SOON AS DIURNAL MIXING OCCURS...AROUND 15Z...EXPECT TO SEE SW WINDS
GUSTING AS HIGH AS 40KT...WITH THE STRONGEST WINDS POSSIBLE BETWEEN
17 AND 22Z. WIND SPEEDS WILL DIMINISH AS WINDS DECOUPLE WITH SUNSET.
THEN THE FOCUS WILL BE ON THE COLD FRONT...WHICH AT THIS POINT LOOKS
TO ARRIVE RIGHT AT 12Z TOMORROW...AND THUS NOT MENTIONED IN THIS TAF
ISSUANCE. HOWEVER...THE FRONT WILL BE JUST NORTH OF THE PANHANDLES
THROUGH MUCH OF THE DAY SO THERE IS LOW CONFIDENCE ON TIMING. ALSO OF
LOW CONFIDENCE IS THE POTENTIAL FOR MVFR CEILINGS BEHIND THE FRONT.
THIS WILL DEPEND GREATLY ON THE TIMING OF THE FRONT AND CURRENT
UPSTREAM OBS DO NOT SHOW LOW CEILINGS...THUS THINK IT IS UNLIKELY.
FOR THE 12Z KDHT AND KGUY TAFS...VFR CONDITIONS ARE EXPECTED UNTIL
THE COLD FRONT ARRIVES...THEN THERE IS A MINIMAL RISK THAT MVFR
CEILINGS WILL DEVELOP BEHIND THE FRONT. FOR NOW HAVE ONLY MENTIONED
FEW020 AS IT IS STILL UNLIKELY THIS WILL OCCUR FOR THE REASONS
MENTIONED ABOVE. AS MENTIONED ABOVE...TIMING OF THE FRONT IS
UNCERTAIN AS IT IS EXPECTED TO STALL JUST NORTH OF THE PANHANDLES FOR
MUCH OF THE DAY TODAY. NAM AND GFS THOUGH ARE IN AGREEMENT THAT THE
FRONT WILL NOT ARRIVE AT KGUY OR KDHT UNTIL AFTER 06Z.
JOHNSON
PREV DISCUSSION... /ISSUED 330 AM CST MON JAN 16 2012/
DISCUSSION...
WINDS WILL BE THE ISSUE OF THE DAY. WIND ADVISORY WILL BE IN EFFECT
FROM 11 AM TO 6 PM ACROSS SOUTHWEST TEXAS PANHANDLE. WINDY TO
BREEZY CONDITIONS EXPECTED ELSEWHERE AS STRONG WINDS ALOFT MIX TO
THE SURFACE. WILL INCLUDE AREAS OF BLOWING DUST FOR SOUTHERN AND
WESTERN PARTS OF TEXAS PANHANDLE.
HIGHER DEWPOINTS POISED OVER EASTERN AND SOUTHERN NEW MEXICO WILL
KEEP RELATIVE HUMIDITY VALUES FROM PLUMMETING...YET WITH STRONG WINDS
EXPECTED TODAY WILL ISSUE FIRE DANGER STATEMENT AS MANY AREAS WILL
FALL TO NEAR 20 PERCENT.
COLD FRONT ARRIVES TONIGHT...CAUSING MAXIMUM TEMPERATURES ON TUESDAY
TO BE ABOUT 10 DEGREES BELOW CLIMO. LEE TROF QUICKLY REDEVELOPS ON
WEDNESDAY...WITH SOUTHWEST HALF OF FORECAST AREA RISING ABOVE CLIMO.
BACK DOOR COLD FRONT MOVES INTO NORTHEAST PART OF FORECAST AREA ON
THURSDAY...WHILE REMAINING SECTIONS REMAIN VERY WARM.
FRIDAY THROUGH SUNDAY EXPECTED TO BE WARM...AS ZONAL FLOW GRADUALLY
TRANSITIONS TO SOUTHWEST. NO POPS IN FORECAST. 03
COCKRELL
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS WILL DEVELOP TODAY AS RELATIVE
HUMIDITY VALUES FALL TO AROUND 20 PERCENT. NORTHEAST WINDS ON
TUESDAY WILL BE MOIST...AND WILL TREND TO EAST AND SOUTHEAST
TUESDAY AFTERNOON AND EVENING. ELEVATED FIRE WEATHER CONDITIONS ARE
POSSIBLE ON WEDNESDAY...SATURDAY AND SUNDAY...AS DRY SOUTHWEST
WINDS INCREASE...ESPECIALLY OVER WESTERN SECTIONS. 03
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...DONLEY...GRAY...HANSFORD...
HUTCHINSON...SHERMAN.
HIGH WIND WARNING UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: DALLAM...DEAF SMITH...HARTLEY...MOORE...OLDHAM...
POTTER...RANDALL.
OK...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: CIMARRON.
&&
$$
17/08
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1122 AM CST MON JAN 16 2012
...WINDY TO VERY WINDY CONDITIONS EXPECTED ACROSS MUCH OF THE
PANHANDLES THIS AFTERNOON...
.UPDATE...
ISSUED A HIGH WIND WARNING FOR THE WEST TEXAS PANHANDLE INCLUDING
AMARILLO...CANYON...HEREFORD...AND DALHART. EXPANDED WIND ADVISORY
EAST TO INCLUDE BOISE CITY...STRATFORD...BORGER...PAMPA...AND
CLARENDON.
INCREASED WINDS AND HIGHEST ACROSS THE AREA THIS AFTERNOON.
&&
.DISCUSSION...
UPGRADE TO A HIGH WIND WARNING FOR THE WEST TEXAS PANHANDLE THIS
AFTERNOON AS LATEST TUCUMCARI NM PROFILER INDICATED 45-55 KT 2-3 KM
MSL...ABOUT 3000-8000 FT AGL. HAVE MODERATE TO HIGH CONFIDENCE THAT
THESE WINDS WILL MIX DOWN TO THE SURFACE THIS AFTERNOON IN THE
WARNING AREA...PARTICULARLY IN THE 2 TO 6 PM TIME FRAME.
EXPANDED THE WIND ADVISORY FARTHER EAST AS WELL THINKING HIGHER WINDS
WILL MIX EASTWARD DURING THE AFTERNOON.
BLOWING DUST IS ANOTHER CONCERN THIS AFTERNOON DUE TO DRY SOILS AND
STRONG WINDS. WILL CONTINUE TO EVALUATE THROUGHOUT THE AFTERNOON.
THERE IS A SMALL CHANCE THAT A FEW THUNDERSTORMS COULD DEVELOP IN THE
2 TO 8 PM CST TIME FRAME ACROSS THE AREA AS LATEST RUC13 INDICATED
LIFTED INDICES 0 TO -2 AND UP TO 400 J/KG. CONVECTIVE TEMPERATURES IN
THE MID 60S TO LOWER 70S MAY BE REACHED. THESE STORMS COULD IGNITE
FIRES AND PRODUCE VERY LITTLE RAIN DUE TO HIGH CLOUD BASES. IN
ADDITION...VARIABLE WIND GUSTS COULD OCCUR. DUE TO LOW CONFIDENCE
ESPECIALLY IN REGARDS TO THE AMOUNT OF LOW LEVEL MOISTURE...KEPT
THUNDER MENTION OUT OF FORECAST FOR NOW.
INCREASED HIGHS SLIGHTLY AS WELL WITH A GOOD AMOUNT OF SUN EXPECTED.
CUMULUS CLOUDS WILL DEVELOP AND FILL IN LATER THIS AFTERNOON.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.FIRE WEATHER...
WINDY TO VERY WINDY CONDITIONS WILL PREVAIL THIS AFTERNOON...THOUGH
RELATIVE HUMIDITY LEVELS SHOULD STAY ABOVE 20 PERCENT.
THERE IS A SMALL CHANCE FOR DRY LIGHTNING BETWEEN 2 AND 8 PM CST THIS
AFTERNOON WHICH COULD IGNITE FIRES.
MBS
&&
.PREV DISCUSSION... /ISSUED 525 AM CST MON JAN 16 2012/
AVIATION...
FOR THE 12Z KAMA TAF...VFR CONDITIONS WILL CONTINUE UNTIL THE FRONT
MOVES THROUGH...AND ARE LIKELY EVEN AFTER THE COLD FRONT ARRIVES. AS
SOON AS DIURNAL MIXING OCCURS...AROUND 15Z...EXPECT TO SEE SW WINDS
GUSTING AS HIGH AS 40KT...WITH THE STRONGEST WINDS POSSIBLE BETWEEN
17 AND 22Z. WIND SPEEDS WILL DIMINISH AS WINDS DECOUPLE WITH SUNSET.
THEN THE FOCUS WILL BE ON THE COLD FRONT...WHICH AT THIS POINT LOOKS
TO ARRIVE RIGHT AT 12Z TOMORROW...AND THUS NOT MENTIONED IN THIS TAF
ISSUANCE. HOWEVER...THE FRONT WILL BE JUST NORTH OF THE PANHANDLES
THROUGH MUCH OF THE DAY SO THERE IS LOW CONFIDENCE ON TIMING. ALSO OF
LOW CONFIDENCE IS THE POTENTIAL FOR MVFR CEILINGS BEHIND THE FRONT.
THIS WILL DEPEND GREATLY ON THE TIMING OF THE FRONT AND CURRENT
UPSTREAM OBS DO NOT SHOW LOW CEILINGS...THUS THINK IT IS UNLIKELY.
FOR THE 12Z KDHT AND KGUY TAFS...VFR CONDITIONS ARE EXPECTED UNTIL
THE COLD FRONT ARRIVES...THEN THERE IS A MINIMAL RISK THAT MVFR
CEILINGS WILL DEVELOP BEHIND THE FRONT. FOR NOW HAVE ONLY MENTIONED
FEW020 AS IT IS STILL UNLIKELY THIS WILL OCCUR FOR THE REASONS
MENTIONED ABOVE. AS MENTIONED ABOVE...TIMING OF THE FRONT IS
UNCERTAIN AS IT IS EXPECTED TO STALL JUST NORTH OF THE PANHANDLES FOR
MUCH OF THE DAY TODAY. NAM AND GFS THOUGH ARE IN AGREEMENT THAT THE
FRONT WILL NOT ARRIVE AT KGUY OR KDHT UNTIL AFTER 06Z.
JOHNSON
PREV DISCUSSION... /ISSUED 330 AM CST MON JAN 16 2012/
DISCUSSION...
WINDS WILL BE THE ISSUE OF THE DAY. WIND ADVISORY WILL BE IN EFFECT
FROM 11 AM TO 6 PM ACROSS SOUTHWEST TEXAS PANHANDLE. WINDY TO
BREEZY CONDITIONS EXPECTED ELSEWHERE AS STRONG WINDS ALOFT MIX TO
THE SURFACE. WILL INCLUDE AREAS OF BLOWING DUST FOR SOUTHERN AND
WESTERN PARTS OF TEXAS PANHANDLE.
HIGHER DEWPOINTS POISED OVER EASTERN AND SOUTHERN NEW MEXICO WILL
KEEP RELATIVE HUMIDITY VALUES FROM PLUMMETING...YET WITH STRONG WINDS
EXPECTED TODAY WILL ISSUE FIRE DANGER STATEMENT AS MANY AREAS WILL
FALL TO NEAR 20 PERCENT.
COLD FRONT ARRIVES TONIGHT...CAUSING MAXIMUM TEMPERATURES ON TUESDAY
TO BE ABOUT 10 DEGREES BELOW CLIMO. LEE TROF QUICKLY REDEVELOPS ON
WEDNESDAY...WITH SOUTHWEST HALF OF FORECAST AREA RISING ABOVE CLIMO.
BACK DOOR COLD FRONT MOVES INTO NORTHEAST PART OF FORECAST AREA ON
THURSDAY...WHILE REMAINING SECTIONS REMAIN VERY WARM.
FRIDAY THROUGH SUNDAY EXPECTED TO BE WARM...AS ZONAL FLOW GRADUALLY
TRANSITIONS TO SOUTHWEST. NO POPS IN FORECAST. 03
COCKRELL
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS WILL DEVELOP TODAY AS RELATIVE
HUMIDITY VALUES FALL TO AROUND 20 PERCENT. NORTHEAST WINDS ON
TUESDAY WILL BE MOIST...AND WILL TREND TO EAST AND SOUTHEAST
TUESDAY AFTERNOON AND EVENING. ELEVATED FIRE WEATHER CONDITIONS ARE
POSSIBLE ON WEDNESDAY...SATURDAY AND SUNDAY...AS DRY SOUTHWEST
WINDS INCREASE...ESPECIALLY OVER WESTERN SECTIONS. 03
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 67 23 40 21 58 / 5 5 0 0 0
BEAVER OK 69 18 37 16 48 / 5 5 0 0 0
BOISE CITY OK 63 19 33 17 52 / 5 5 0 0 0
BORGER TX 70 26 39 22 57 / 5 5 0 0 0
BOYS RANCH TX 66 24 39 23 58 / 5 5 0 0 0
CANYON TX 68 27 42 21 62 / 5 5 0 0 0
CLARENDON TX 73 27 42 21 55 / 5 5 0 0 0
DALHART TX 63 21 36 17 54 / 5 5 0 0 0
GUYMON OK 68 18 36 17 53 / 5 5 0 0 0
HEREFORD TX 67 28 41 22 63 / 5 5 0 0 0
LIPSCOMB TX 71 22 38 17 48 / 5 5 0 0 0
PAMPA TX 68 23 37 21 51 / 5 5 0 0 0
SHAMROCK TX 75 25 42 19 50 / 5 5 0 0 0
WELLINGTON TX 76 29 45 22 51 / 5 5 0 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...DONLEY...GRAY...HANSFORD...
HUTCHINSON...SHERMAN.
HIGH WIND WARNING UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: DALLAM...DEAF SMITH...HARTLEY...MOORE...OLDHAM...
POTTER...RANDALL.
OK...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: CIMARRON.
&&
$$
17/08
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
250 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 18Z TUESDAY
1151 AM CST MON JAN 16 2012
DATA ANALYSIS AT 17Z HAS A COLD FRONT EXTENDING FROM CENTRAL LAKE
SUPERIOR THROUGH KLSE...AND THEN THROUGH EASTERN IA. CURRENT
SATELLITE SHOWING MOSTLY HIGH ALTOCUMULUS/CIRRUS WITH BASES AOA
15KFT DRIFTING ACROSS THE REGION AHEAD OF A MID-LEVEL TROUGH
MOVING OUT OF THE INTERMOUNTAIN WEST. MEANWHILE...AN AREA OF MVFR
STRATOCUMULUS WITH OCNL FLURRIES WAS SEEN BY SATELLITE AND
SURFACE OBSERVATIONS ACROSS THE NORTHWEST HALF OF MN WITH A SLOW
DRIFT TO THE SOUTHEAST. RUC RH ANALYSIS AND PROJECTIONS SHOW A
TREND FOR THESE MVFR CLOUDS TO CONTINUE FILLING IN TO THE
SOUTHEAST IN COLD AIR ADVECTION THIS AFTERNOON. ESTIMATED TIME OF
ARRIVAL FOR MVFR CLOUDS AT KRST EXPECTED TO BE AROUND 20Z AND 24Z
AT KLSE. NEXT CONCERN WILL BE SNOW CHANCES TONIGHT ALONG WITH
LIKELIHOOD OF DETERIORATING MVFR CONDITIONS INTO IFR AFTER
MIDNIGHT. TROUGH OF LOW PRESSURE OVER THE INTERMOUNTAIN WEST WILL
MOVE OUT INTO THE PLAINS LATE TONIGHT WITH LIFT PRODUCING -SN AT
KRST AROUND 06Z AND AT KLSE AROUND 07Z. MVFR CONDITIONS EXPECTED
TO QUICKLY DROP INTO IFR CATEGORY AROUND 08Z AT KRST AND AROUND
09Z AT KLSE...THEN REMAINING THERE THROUGH THE REST OF TUESDAY
MORNING. RIGHT NOW IT APPEARS 1-2 INCHES OF SNOW ACCUMULATION IS
EXPECTED LATE TONIGHT THROUGH TUESDAY. ALSO OF CONCERN WILL BE
POSSIBLE BLOWING AND DRIFTING OF THIS -SN IMPACTING KRST TUESDAY
MORNING WITH NORTH WINDS OF 15-25KT. DID NOT CARRY THE BLSN FOR
NOW...BUT WILL PASS ONTO THE EVENING/OVERNIGHT FORECASTER TO KEEP
AN EYE ON FOR POSSIBLE INCLUSION IN LATER TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST MON JAN 16 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION..... DAS