Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/10/12
AREA FORECAST DISCUSSION
NWS TOPEKA KS
548 PM CST SUN DEC 9 2012
...UPDATE TO AVIATION...
.DISCUSSION...
20Z WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL TROUGH FROM THE FOUR
CORNERS REGION INTO THE DAKOTAS. ONE SHORTWAVE WAS LIFTING
NORTHEAST INTO MN WITH ANOTHER SHORTWAVE OVER THE CO AND NM
ROCKIES. AT THE SURFACE...A VERY STRONG COLD FRONT HAS PUSHED
SOUTH INTO NORTH TX AND EAST INTO CENTRAL MO. AREA OBSERVATIONS
INDICATE STRONG COLD AND DRY AIR ADVECTION IS ONGOING. RADAR
TRENDS THROUGHOUT THE DAY HAVE SUPPORTED THE IDEA THAT THE DRY AIR
NEAR THE SURFACE IS TO MUCH FOR WEAK FRONTOGENESIS IN THE MID
LEVELS TO OVERCOME.
FOR TONIGHT AND MONDAY...MODELS SHOW LITTLE OR NO LARGE SCALE
FORCING THROUGH THE PERIOD WITH THE ONLY INDICATION OF FORCING FOR
PRECIP BEING WEAK MID LEVEL FRONTOGENESIS THROUGH THE EARLY EVENING.
GIVEN THE CONTINUED ADVECTION OF DRY AIR IN THE LOWER TROPOSPHERE...
THINK PRECIP CHANCES ARE PRETTY CLOSE TO NIL. BY MONDAY...THE COLD
SURFACE RIDGE OF HIGH PRESSURE WITH VERY DRY AIR IS EXPECTED TO
DOMINATE THE WEATHER AS THE SHORTWAVE OVER THE SOUTHERN ROCKIES
PASSES MAINLY TO THE SOUTH OF THE FORECAST AREA. THEREFORE THE
FORECAST WILL REMAIN DRY. ABOUT THE ONLY WEATHER CONCERN IS CLOUD
COVER OVERNIGHT. VISIBLE SATELLITE SHOWS AN AREA OF STRATOCU MOVING
SWIFTLY SOUTH ACROSS EASTERN NEB. THE RAP SHOWS THIS DECK OF LOW
CLOUDS HANGING IN ACROSS NORTHEAST AND EAST CENTRAL KS THROUGH MUCH
OF THE NIGHT...AND THE NAM AND GFS TO A LESSER EXTENT SUPPORT THE
IDEA. SO THINK SKIES WILL BE MOSTLY CLOUDY TONIGHT. BECAUSE OF THIS
HAVE KEPT LOWS A DEGREE OR TWO WARMER THAN THE MOS GUIDANCE ACROSS
EASTERN KS. ADDITIONALLY A STRONGLY MIXED BOUNDARY LAYER SHOULD HELP
KEEP LOWS FROM PLUMMETING. NORTH CENTRAL KS COULD SEE SINGLE DIGIT
LOWS WHERE SKIES SHOULD CLEAR OUT SOONER. WITH SUCH A COLD START TO
THE DAY...HIGHS ARE EXPECTED TO ONLY MAKE IT INTO THE LOWER AND MID
30S FOR MONDAY EVEN WITH MOSTLY SUNNY SKIES.
WOLTERS
MID WEEK PERIODS LOOKING RATHER BENIGN. SOME MID AND HIGH CLOUDS
SHOULD BE ALL THAT RESULTS FROM THE NEXT UPPER WAVE PASSING THROUGH
THE CENTRAL PLAINS MONDAY NIGHT INTO EARLY TUESDAY. LOW LEVEL FLOW
REMAINS MAINLY WESTERLY TUESDAY FOR WEAK WARM AIR ADVECTION...AND
WAA INCREASES INTO WEDNESDAY AND THURSDAY AS BROAD RIDGING OVERTAKES
THE CENTRAL AND EASTERN CONUS. THE DEGREE OF MIXING INTO THE WARM
AND DRY MID LEVELS IS THE MAIN QUESTION FOR HOW WARM HIGHS WILL GET.
BUMPED THEM UP A FEW DEGREES AT THIS POINT BUT FURTHER INCREASES MAY
BE NEEDED. SSW WINDS INCREASE FOR WEDNESDAY INTO THURSDAY AND
RELATIVE HUMIDITIES MAY DROP TO LEVELS OF SOME CONCERN FOR FIRE
WEATHER MAINLY ON WEDNESDAY.
MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT WITH WESTERN TROF AND
UPPER LOW IN THE SOUTHWEST CONUS ON THURSDAY...BUT DIFFERENCES
MAGNIFY QUICKLY INTO THE WEEKEND. THE 12Z ECMWF PUSHES THE LOW EAST
AHEAD OF THE NORTHERN TROF AND ALLOWS A LOW TO RE-CLOSE AND DEEPEN
RAPIDLY OVER THE CENTRAL PLAINS...WHILE THE 12Z GFS KEEPS THE
SOUTHERN LOW BEHIND THE NORTHERN TROF FOR A WEAKENING WAVE IN THE
PLAINS. MODERATE PRECIPITATION CHANCES REMAIN...CENTERED AROUND
FRIDAY NIGHT...WITH SOME OPPORTUNITY FOR CONVECTION IN THE MORE
AMPLIFIED SOLUTIONS AND MINOR CONCERN FOR WINTRY PRECIP AS THE EVENT
WINDS DOWN. TEMPS SHOULD RETURN TO NEAR MID-DECEMBER NORMALS FOR
SUNDAY.
65
&&
.AVIATION...
VFR CATEGORY AT KTOP/KFOE/KMHK FOR THE NEXT FEW HOURS AT
KTOP/KFOE/KMHK. OBSERVATIONS SHOW A BORDERLINE VFR TO MVFR STRATUS
DECK SHIFTING SOUTH OVER NORTHERN KANSAS...JUST PASSING OVER KMHK AT
VFR. SOME UNCERTAINTY AS TO WHETHER CIGS FALL TO MVFR AT KTOP/KFOE.
BELIEVE BASED ON SHORT TERM GUDANCE THE BEST LOW LVL MOISTURE WILL
REACH KTOP/KFOE WHERE MVFR IS INTRODUCED AFTER 02Z. DRIER AIR AT
KMHK SHOULD HOLD THE BKN STRATUS AT LOW END VFR. DRIER AIR WILL
QUICKLY FOLLOW CLEARING SKIES. STRONG NORTHWEST WINDS WILL PERSIST
ABOVE 10 KTS SUSTAINED WITH GUSTS AOA 20 KTS. WINDS WANE BLO 10
KTS AND BACK TOWARDS THE WEST TOWARDS END OF THE PERIOD.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1128 AM CST SAT DEC 8 2012
.UPDATE...
THE FORECAST WAS UPDATED TO INCREASE CLOUD COVER AS THE LATEST
VISIBLE SATELLITE TREND SUPPORTS THE HRRR WITH WIDESPREAD LOW
CEILINGS OVERSPREADING THE AREA TODAY. THIS MAY ALSO IMPACT
HIGH TEMPERATURES...ALTHOUGH UPPER 40S WILL LIKELY BE REACHED EVEN WITH
LIMITED INSOLATION THROUGH THE AFTERNOON HOURS.
MWM
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
TRENDED FLIGHT CATEGORIES DOWN THIS AFTERNOON AND TONIGHT AS LOW
LEVEL ISENTROPIC UPGLIDE WILL SUPPORT WIDESPREAD MVFR/AREAS OF IFR
CIGS THROUGH THE AFTERNOON AND TONIGHT. AS THE COLD FRONT
ARRIVES AFTER 06Z ACROSS CENTRAL KANSAS...CEILINGS WILL BEGIN TO LIFT
WITH MVFR/VFR PREVAILING ONCE AGAIN. WINDS BEHIND THE FRONT WILL
INCREASE TO 20-30 KNOTS WITH LIGHT SNOW DEVELOPING ACROSS PORTIONS
OF CENTRAL KANSAS ON SUNDAY.
MWM
&&
.PREV DISCUSSION... /ISSUED 534 AM CST SAT DEC 8 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN AVIATION FORECAST CONCERN IS MVFR/IFR CONDITIONS IN THE
NEAR TERM...AND GUSTY NORTHWEST WINDS AFTER THE FRONTAL PASSAGE
TONIGHT AND AGAIN MVFR/IFR CONDITIONS BEHIND THE FRONT.
SURFACE HIGH PRESSURE WILL SLIDE OVERHEAD TODAY WITH LIGHT WINDS
BECOMING SOUTHERLY FROM WEST TO EAST. MVFR/IFR CONDITIONS AT KCNU
THIS MORNING ARE EXPECTED TO IMPROVE TO VFR BY LATE MORNING. THE
NEXT POTENT COLD FRONT WILL MOVE ACROSS THE AREA
OVERNIGHT...IMPACTING KRSL/KSLN AROUND 06-07Z...KICT/KHUT AROUND
08-09Z AND KCNU JUST TOWARD THE END OF THE TAF PERIOD. WINDS WILL
BECOME NORTH-NORTHWESTERLY BUT THE STRONGEST WINDS WILL LAG JUST A
BIT BEHIND THE INITIAL WIND SHIFT. SOME LOW CLOUDS ARE ALSO
EXPECTED AS THE FRONT MOVES IN WITH MVFR CONDITIONS FORECASTED AT
KRSL AND KSLN JUST PRIOR TO 12Z SUNDAY MORNING. HAVE LEFT
PRECIPITATION CHANCES OUT AT THIS TIME...WITH LOW CONFIDENCE THIS
MORNING...WILL WAIT UNTIL LATER FORECASTS HAVE A BETTER HANDLE ON
HOW PRECIP WILL IMPACT THE TERMINALS.
BILLINGS
PREV DISCUSSION... /ISSUED 332 AM CST SAT DEC 8 2012/
DISCUSSION...
TODAY:
MAIN CHALLENGE WILL BE IF LOW CLOUDS IN SOUTHEAST KS WILL BREAK
BEFORE RETURNING BACK NORTH LATER TODAY. CLOUDS ARE EXPECTED TO
INCREASE ACROSS MOST OF THE AREA LATER TODAY.
TONIGHT-SUN NIGHT:
MODELS HAVE COME INTO BETTER AGREEMENT...BUT LIMITED MOISTURE AND
POOR PHASING OF DYNAMICS WILL LIKELY PRECLUDE ANY SIGNIFICANT QPF.
BRIEF PERIOD OF ISENTROPIC LIFT MAY LEAD TO SOME LIGHT RAIN THIS
EVENING NEAR LEADING EDGE OF LOW LEVEL MOISTURE. AS 850MB WINDS
VEER...LIFT WILL DECREASE PRIOR TO ARRIVAL OF FRONT. THE FRONT SHOULD
ENTER FAR NORTHWEST SECTIONS OF FORECAST AREA AROUND 06Z AND RACE
SOUTHEAST AND EXIT AREA AROUND 1200 UTC. COMBO OF NEAR ADVISORY
LEVEL WINDS WILL AID COLD AIR ADVECTION RESULTING IN STEADY TO
SLOWLY FALLING TEMPERATURES AT MOST LOCATIONS. PRECIPITATION
CHANCES WILL INCREASE SLIGHTLY THROUGH THE DAY WITH THE
PREDOMINATE WEATHER TYPE EXPECTED TO BE FLURRIES. THIS IS DUE TO
LACK OF INSTABILITY IN SNOW GROWTH ZONE AND INFLUX OF LOW LEVEL
DRY AIR THROUGHOUT THE PERIOD. WILL HANG ONTO FLURRIES UNTIL
MIDNIGHT AS MID LEVEL BAND OF MOISTURE MOVES THROUGH. VERY DRY
AIR AND DIMINISHING WINDS/LACK OF PRECIPITATION WILL LIKELY ALLOW
FOR SINGLE DIGIT LOWS SOUTH ACROSS CENTRAL KS SUN NIGHT.
MON-FRI:
AFTER VERY CHILLY START TO MONDAY...EXPECT A GRADUAL MODERATION OF
THE COLD AIRMASS. SHORTWAVE MOVING THROUGH MIDWEEK WILL LIKELY BE
MOISTURE STARVED AND FRONT WILL COME THROUGH DRY. SLIGHTLY BETTER
CHANCE FOR PRECIPITATION ON FRI AS DECENT SHORTWAVE MOVES OUT OF
SOUTHWEST US WITH APPARENTLY GOOD SURFACE CYCLOGENESIS. -HOWERTON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
AREAS CONTINUING CAUSE FOR CONCERN ARE GENERALLY ALONG & SE OF TURNPIKE
WHERE WIDESPREAD 1,200-1,500FT CIGS PERSIST WHILE IFR DECKS CONTINUE TO
PESTER EXTREME SE KS WHERE VERY CLOSE TO A WEAK SE DRIFTING COLD FRONT.
THE SE PROGRESS OF THE COLD FRONT WILL NEED TO BE WATCHED CLOSELY. FOR
NOW IT APPEARS THE FRONT MIGHT MAKE SUFFICIENT PROGRESS FOR IFR CIGS TO
REMAIN E-S OF KCNU...HOWEVER MVFR VSBYS ARE LIKELY OVER KCNU THROUGH
~15Z. PER SATELLITE IMAGERY KICT REMAINS SITUATED ALONG WRN PERIPHERY
OF "LOW-END" MVFR STRATUS & WITH WEAK HIGH PRESSURE CONTINUING TO DRIFT
E EXPECT THE TERMINAL TO REALIZE VFR STATUS ~09Z BUT THIS TOO WILL NEED
TO BE WATCHED CLOSELY.
ES
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 49 31 39 14 / 10 10 10 10
HUTCHINSON 48 28 37 12 / 10 10 10 10
NEWTON 48 31 37 12 / 10 10 10 10
ELDORADO 49 32 39 14 / 10 10 10 10
WINFIELD-KWLD 50 33 41 14 / 10 10 20 10
RUSSELL 48 27 33 6 / 0 20 10 10
GREAT BEND 48 28 34 7 / 10 10 10 10
SALINA 48 28 35 12 / 10 20 10 10
MCPHERSON 48 29 36 12 / 10 20 10 10
COFFEYVILLE 50 42 45 19 / 10 10 20 10
CHANUTE 50 38 42 15 / 10 10 20 10
IOLA 50 37 42 15 / 10 10 20 10
PARSONS-KPPF 50 40 44 16 / 10 10 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1002 PM MST FRI DEC 7 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 144 PM MST FRI DEC 7 2012
LATEST SATELLITE IMAGERY DEPICTS AN UPPER LEVEL TROUGH AXIS
EXTENDING FROM SOUTHEASTERN COLORADO NORTHEAST INTO NORTHERN MINNESOTA.
BEHIND THE TROUGH AXIS RUC ANALYSIS PLACES A SHORT WAVE TROUGH OVER
THE NE/SD LINE. AT THE SURFACE A PRE-FRONTAL TROUGH WAS MOVING
SOUTHEAST THROUGH THE PLAINS. SUBSIDENCE BEHIND THE SHORT WAVE TROUGH
AND TROUGH AXIS HAS LEAD TO CLEARING SKIES BEHIND THE SURFACE
FEATURE.
LATE THIS EVENING A WEAK SHORT WAVE TROUGH WILL DEVELOP OVER EASTERN
COLORADO AND PROGRESS ACROSS THE WESTERN HALF OF THE TRI-STATE
AREA. SREF/NAM ISENTROPIC ANALYSIS INDICATES LIFT AHEAD OF THE
SHORT WAVE TROUGH AROUND 700MB WHERE POINT SOUNDINGS ALSO SATURATE.
THE DRAWBACK IS A DRY LAYER BELOW THIS WHICH WILL LIMIT HOW MUCH
SNOW WILL REACH THE GROUND. THE MCCOOK AND NORTON AREA HAD A
SIMILAR SETUP THIS MORNING...WITH THE MCCOOK AIRPORT REPORTING
DRIZZLE. WITH THIS IN MIND WILL PLACE A MENTION OF FLURRIES AHEAD
OF THE SHORT WAVE TROUGH. THE FLURRIES WILL GENERALLY MOVE FROM
SOUTHWEST TO NORTHEAST DURING THE NIGHT OVER THE WESTERN HALF OF THE
AREA.
SATURDAY THE SHORT WAVE TROUGH WILL CONTINUE TO MOVE ACROSS THE AREA
DURING THE MORNING. HAVE THE FLURRIES CHANGING TO DRIZZLE
DURING THE LATE MORNING AS SURFACE TEMPERATURES WARM INTO THE LOWER
30S. THE ISENTROPIC LIFT AHEAD OF THE TROUGH WILL EXIT THE AREA BY
EARLY AFTERNOON. SOUTH WINDS WILL BE BREEZY DURING THE AFTERNOON AS
25KT 850MB WINDS MIX TO THE GROUND AND THE SURFACE PRESSURE GRADIENT
TIGHTENS. THE BREEZY WINDS WILL HELP WARM TEMPERATURES AHEAD OF THE
NEXT COLD FRONT...WHICH WILL MOVE INTO THE AREA DURING THE MID TO
LATE AFTERNOON. LIFTING AND MOISTURE WILL BE BEST ALONG AND SHORTLY
BEHIND THE FRONT. HOWEVER MODELS SHOW A FAIRLY DEEP DRY LAYER AS
THE FRONT MOVES THROUGH...WHICH MAY LIMIT THE AMOUNT OF RAIN THAT
REACHES THE GROUND. MODELS SHOW RAPID PRESSURE RISE BEHIND THE COLD
FRONT...WHICH WILL CAUSE WINDS TO STRENGTHEN BEHIND THE FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 247 PM MST
FRI DEC 7 2012
THE COLD FRONT WILL CONTINUE TO PUSH ACROSS THE FORECAST AREA
SATURDAY NIGHT. THE FAVORED AREA OF PRECIPITATION WILL INITIALLY BE
ACROSS THE NORTHERN SECTIONS OF THE FORECAST AREA IN THE VICINITY
OF THE FRONT WITH LIGHT RAIN CHANGING QUICKLY OVER TO LIGHT SNOW
AROUND SUNSET. A SLIGHT CHANCE OF LIGHT SNOW WILL SPREAD ACROSS THE
FORECAST AREA WITH THE FRONT...WITH THE BEST CHANCE OF
PRECIPITATION REMAINING ALONG THE NORTHERN TIER OF COUNTIES WHERE
THE SYNOPTIC SCALE LIFT REMAINS GREATER AS A SERIES OF SHORT WAVES
SHEAR OUT ACROSS THE PLAINS AHEAD OF THE MAIN UPPER TROUGH. THE
POSSIBILITY OF PRECIPITATION DECREASES THROUGH THE REMAINDER OF
SATURDAY NIGHT AND SUNDAY MORNING...WITH LIGHT SNOW ENDING BY MID
DAY ON SUNDAY. WITH THE STEEP PRESSURE GRADIENT REMAINING OVER THE
CENTRAL HIGH PLAINS REGION...EXPECT NORTH WINDS OF 20-30 MPH WILL
BE COMMON DURING THE DAY ON SUNDAY.
THE PRIMARY DEEP UPPER TROUGH SWEEPS QUICKLY THROUGH THE REGION
SUNDAY NIGHT WITH A COLD AREA OF HIGH PRESSURE MOVING IN BEHIND
THE FRONT. OVERNIGHT LOW TEMPERATURES WILL DROP INTO THE SINGLE
DIGITS AS SKIES ALSO BEGIN TO CLEAR OUT AND WINDS SLACKEN SUNDAY
NIGHT.
A SERIES OF OPEN WAVES WILL MOVE THROUGH THE UPPER FLOW NEXT
WEEK. ALTHOUGH THE PATTERN REMAINS ACTIVE...NO ADDITIONAL
PRECIPITATION IS EXPECTED THROUGH NEXT WEEK. COLDER TEMPERATURES
WILL CONTINUE INTO THE BEGINNING OF NEXT WEEK WITH A GRADUAL
WARMING BRINGING TEMPERATURES BACK TO NEAR AVERAGE FOR THIS TIME
OF YEAR THROUGH THE MIDDLE AND END OF NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 958 PM MST FRI DEC 7 2012
VARIABLE AND CHANGING WINDS/CEILINGS EXPECTED THROUGH THE PERIOD.
AFTER STARTING OUT LIGHT AND VARIABLE...WINDS WILL SHIFT TO THE
SOUTH AND INCREASE/BECOME DURING THE MID AND LATE MORNING HOURS.
WINDS WILL DECREASE RIGHT BEFORE A STRONG COLD FRONT MOVES THROUGH
THE AREA IN THE 03Z TO 06Z TIME FRAME. STRONG AND GUSTY WINDS ARE
EXPECTED THEN. IT IS POSSIBLE THAT RIGHT BEHIND THE FRONT CEILINGS
WILL BECOME MVFR OR LOWER TO JUST ABOVE MVFR. ANY LOW CEILING OR
VERY LIGHT PRECIPITATION IS NOT EXPECTED TO LAST VERY LONG OR
CAUSE ANY SIGNIFICANT VISIBILITY RESTRICTION.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...LOCKHART
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
516 PM EST SAT DEC 8 2012
.SYNOPSIS...
A WEAK WAVE OF LOW PRESSURE WILL CROSS THE REGION THIS EVENING
BEFORE MOVING OUT OVERNIGHT. HIGH PRESSURE WILL CROSS THE REGION
SUNDAY. LOW PRESSURE WILL THEN CROSS THE REGION MONDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
510 PM UPDATE...
ADDED THE MENTION OF FZRA INTO NORTHERN AND WEST-CENTRAL ZONES
TONIGHT AS THE LATEST RUC AND NAM SOUNDINGS INDICATE SFC
TEMPERATURES FALLING BACK W/WARM FROM 1K TO 4K FT INDICATING THE
POTENTIAL FOR FREEZING PRECIP. RAIN IN THE HOULTON AND MILLINOCKET
REGION BUT COULD VERY WELL SEE FREEZING PRECIP IN THESE AREAS
AFTER 8 PM. COULD NEED A WINTER WEATHER/FREEZING RAIN ADVISORY
TONIGHT. WILL ASSESS THIS FURTHER.
DOWNEAST AND COAST WILL STAY WARM ENOUGH FOR RAIN. HOWEVER, WE
WILL NEED MONITOR THE CENTRAL AREAS SUCH AS SOUTHERN PISCATAQUIS,
CENTRAL PENOBSCOT AND NORTHERN WASHINGTON COUNTIES AS WELL FOR THE
POTENTIAL FOR FZRA LATER TONIGHT.
PREVIOUS DISCUSSION...
A WEAK SYSTEM WILL CONTINUE TO AFFECT THE AREA INTO
TONIGHT. A SHIELD OF PRECIPITATION ASSOCIATED WITH A COASTAL WAVE
OF LOW PRESSURE CONTINUES TO AFFECT AREAS MAINLY SOUTH OF A PATTEN
TO HOULTON LINE. MOST OF THIS PRECIPITATION IS FALLING AS RAIN BUT
SOME SNOW OR SLEET WILL CONTINUE TO BE POSSIBLE ALONG THE NORTHERN
PERIPHERY OF THE PRECIPITATION SHIELD FOR PLACES LIKE MILLINOCKET.
THIS AREA OF RAIN/MIXED PRECIPITATION WILL DEPART FROM WEST TO
EAST THROUGH THE LATE AFTERNOON INTO THIS EVENING. MEANWHILE
ACROSS THE NORTH, PRECIPITATION ASSOCIATED WITH THE PRIMARY LOW
CURRENTLY LOCATED OVER NEW YORK STATE WILL BRUSH THE AREA THIS
EVENING. THIS PRECIPITATION WILL BE GENERALLY LIGHT AND LOOKS TO
FALL AS MAINLY SNOW IN ST JOHN VALLEY WITH A LITTLE RAIN OR PATCHY
FREEZING RAIN POTENTIALLY MIXING IN JUST TO THE SOUTH TOWARD THE
CARIBOU AREA. SINCE ANY FREEZING RAIN THAT OCCURS LOOKS TO BE
LIGHT AND PATCHY AN ADVISORY IS NOT WARRANTED AT THIS TIME. ALSO,
ANY SNOW ACCUMULATION LOOKS TO BE UNDER AN INCH AND CONFINED TO
AREAS MAINLY NORTH OF CARIBOU.
THE TWO LOWS WILL CONSOLIDATE TONIGHT AS THE SYSTEM MOVES EAST INTO
THE MARITIMES AND INTENSIFIES. STEADIER PRECIPITATION WILL TAPER
OFF BUT LINGERING FLURRIES AND SNOW SHOWERS WILL BE POSSIBLE IN THE
NORTH. IN ADDITION, WINDS WILL INCREASE.
SUNDAY WILL BE DRY AND BRIGHT BUT WINDY WITH NW WINDS GUSTING 20 TO
POTENTIALLY AS HIGH AS 30 MPH IN THE NORTH. THESE WINDS WILL ABATE
THROUGH THE AFTERNOON AS HIGH PRESSURE BRIEFLY MOVES IN. HIGHS
WILL RANGE FROM NEAR 30 IN THE NORTH TO AROUND 40 SOUTH.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
COLD ARCTIC LIKE SFC HI PRES OVR E CNTRL QB WILL BRING COLD DRY
CONDITIONS FOR SUN EVE. RIGHT ON THE HEELS OF THIS SYSTEM...LOW
PRES AND A SUPPORTING S/WV FROM THE GREAT LKS WILL BRING
INCREASING CLDNSS W TO E ACROSS THE FA OVRNGT SUN WITH LGT SNFL
FOLLOWING BEFORE THE DAYBREAK HRS ERLY MON MORN.
FOR THIS UPDATE...WE TOOK A SIG BLEND PTN WITH THE 12Z DTMNSTC ECMWF
FOR STORM TRACK ALG WITH HI/LOW TEMPS MON AND MON NGT. THE REASON
FOR GOING THIS DIRECTION IS THAT THE NAO TELECONNECTION PATTERN IS
FCST TO BECOME SIGNIFICANTLY NEGATIVE OVR THE NEXT FEW DAYS...MEANING
THAT BLOCKING NEAR GREENLAND IS NOT LIKELY TO ALLOW THE COLD SFC
HI PRES FROM EXITING LABRADOR DURING THIS UPCOMING EVENT...KEEPING
LLVL COLD AIR WELL ENTRENCHED ACROSS NRN PTNS OF THE FA.
IN DOING THIS WE TREND WITH A FURTHER S TRACK OF THE PRIMARY AND
TRIPLE POINT SECONDARY SFC LOW...MORE TOWARD CNTRL PTNS OF THE FA
RATHER THAN NRN PTNS. THIS FURTHER S TRACK WILL KEEP NRN PTNS OF
THE FA FROM CHGNG TO ALL RN IN THIS EVENT...WITH THE BEST
POTENTIAL OF PL AND FZRA OVR NRN AREAS DURG THE AFTN AND EVE HRS
OF MON. IN FACT...IF TDY`S 12Z ECMWF (SIMILAR TO LAST NGT`S 00Z
ECMWF) RUN IS CORRECT...THEN THE ST JOHN VLY OF XTRM NRN AROOSTOOK
COUNTY COULD RECEIVE ALL SN WITH THIS EVENT...HOWEVER...FOR THIS
UPDATE WE STILL INDICATE A FEW HRS OF MIX HERE VERY LATE MON INTO
ERLY MON EVE. FURTHER S...SNFL WILL NOT LAST AS LONG INTO MON AND
CHGOVR QUICKER TO PL AND FZRA AND THEN PLAIN RN WITH COASTAL AREAS
LEADING THE WAY. PRELIM TOTAL SNFL AND ICE WILL RANGE FROM 1 TO 2
INCHES AND UP TO A TENTH OF AN INCH RESPECTIVELY FOR DOWNEAST AND
CNTRL AREAS AND 2 TO 4 INCHES WITH ARND A TENTH OF AN INCH NRN
AREAS...WITH POSSIBLY A LITTLE MORE SN AND LESS ICE OVR THE ST
JOHN VLY.
MIXED PRECIP SHOULD TRANSITION BACK TO SN SHWRS ACROSS NRN AND
CNTRL PTNS OF THE FA OVRNGT MON. DOWNEAST AREAS WILL HOLD RAIN
LONGEST MON NGT...WITH S FEW MODELS INDICATING A VERY WEAK
TRAILING SFC WV ALG THE COLD FRONT WHICH MAY CONT SIG QPF IN THE
00-06Z TM FRAME. SFC TEMPS...WHICH WILL REACH A MAX LATE IN THE
DAY MON AND ERLY MON EVE WILL SLOWLY DROP OFF LATE MON NGT. WITH
CONTD LLVL COLD ADVCN ON TUE....HI TEMPS WILL ONLY MARGINALLY
RISE FROM ERLY MORN LOWS...WITH SHALLOW BKN-OVC LLVL COLD ADVCN
SC PERHAPS HOLDING ON OVR NRN PTNS OF THE FA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A RATHER TRANQUIL WEATHER PATTERN CAN BE EXPECTED IN THE LONG TERM.
LOW PRESSURE WILL CONTINUE TO EXIT NORTHEAST OF THE CANADIAN
MARITIMES TUESDAY NIGHT. HIGH PRESSURE WILL BUILD IN BEHIND THE LOW
FOR LATER TUESDAY NIGHT AND REMAIN ACROSS THE REGION THROUGH
THURSDAY. THE HIGH WILL SLIDE TO OUR SOUTHEAST THURSDAY NIGHT AND
FRIDAY. A COLD FRONT WILL THEN APPROACH FROM THE WEST FRIDAY AND
CROSS THE REGION FRIDAY NIGHT. THE FRONT MAY BE ACCOMPANIED BY A FEW
SNOW SHOWERS AS IT CROSSES THE REGION FRIDAY NIGHT. HIGH PRESSURE
WILL BUILD BACK IN FOR SATURDAY. TEMPERATURES THROUGH THE PERIOD
WILL BE CLOSE TO NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: IFR CONDITIONS FOR THE SOUTHERN TERMINALS WILL
CONTINUE THROUGH THIS EVENING DUE TO LOW CLOUDS ALONG WITH AREAS
OF MIST AND FOG. THESE CONDITIONS WILL IMPROVE TO VFR LATE TONIGHT
AS LOW PRESSURE DEPARTS AND NW WINDS INCREASE. LOOK FOR CONDITIONS
TO LOWER TO MVFR IN THE NORTH BY EARLY THIS EVENING WITH A PERIOD
OF IFR LIKELY LATE THIS EVENING IN LIGHT SNOW BEFORE CONDITIONS
IMPROVE OVERNIGHT. SUNDAY WILL BE VFR EVERYWHERE BUT WITH STRONG
AND GUSTY NW WINDS.
SHORT TERM: VFR TO BEGIN WITH SUN EVE THEN CONDITIONS TRANSITIONING
TO IFR LATE SUN NGT IN SN CNTRL AND N AND SN CHGNG TO FZRA AND PL
OVR DOWNEAST AREAS. IFR CONDITIONS CONT MON INTO MON EVE WITH MSLY
RN DOWNEAST SITES AND SN CHG TO PL AND FZRA NRN TAF SITES MON
AFTN...XCPT MIDDAY FOR KHUL. IFR CONDITIONS SHOULD IMPROVE TO MVFR
CONDITIONS NW TO SE ACROSS THE TAF SITES LATE MON NGT AND THEN TO
VFR ALL SITES ON TUE.
&&
.MARINE...
NEAR TERM:
WINDS WILL INCREASE LATER THIS EVENING WITH SCA CONDITIONS
EXPECTED OVERNIGHT THROUGH MUCH OF THE DAY SUNDAY BEFORE WINDS
DIMINISH LATE DAY.
SHORT TERM: INITIALLY NO HDLNS FOR SUN NGT...THEN WINDS AND SEAS
INCREASE TO SCA RANGE FOR MON INTO MON NGT AHEAD AND WITH LOW PRES
TRACKING N OF THE WATERS BEFORE SLOWLY SUBSIDING BLO SCA CONDITIONS
ON TUE BEHIND THE LOW.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 3 PM EST SUNDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...FITZSIMMONS/HEWITT
SHORT TERM...VJN
LONG TERM...DUDA
AVIATION...FITZSIMMONS/HEWITT
MARINE...FITZSIMMONS/HEWITT/VJN
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
846 PM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY THIS
EVENING AND LIFT A WARM FRONT INTO THE REGION. THIS WILL ALLOW
FOR SHOWERS TO MOVE ACROSS THE AREA AND CONTINUE INTO MONDAY. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER
TO SNOW SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING
INTO THE AREA FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A BRIEF INTERLUDE SEEMS LIKELY TO ENSUE BETWEEN THE MAINLY PRE-
WARM FRONTAL ISENTROPIC STRATIFORM PRECIPITATION AND THE WARM
SECTOR CONVECTIVE PRECIPITATION THIS EVENING FOR MANY SECTIONS OF
THE FORECAST AREA. HOWEVER...WITH THE NORTHWARD MIGRATION OF THE
WARM FRONT...MID-LEVEL INSTABILITY DOES INCREASE ALL THE WHILE
SYNOPTIC FORCING VIA UPPER DIVERGENCE FROM A NEARING AND SLIGHTLY
ANTI-CYCLONICALLY CURVED RIGHT ENTRANCE OF AN UPPER JET STREAK
COMES INTO PLAY. THE CURVATURE OF THIS JET STREAK SHOULD HELP TO
GIVE ADDITIONAL AGEOSTROPHIC ENHANCEMENT OF UPPER DIVERGENCE
FIELD AND THEREBY YIELD MORE STRONGLY NEGATIVE OMEGAS. THIS
COUPLED WITH THE DOWNFLOW TRAJECTORY OF MID-LEVEL FORCING VIA
IMPRESSIVE FRONTOGENESIS AND DIFFERENTIAL PVA AS WELL AS A FAIRLY
LOW PENETRATING PV ANOMALY ON THE MODEL CONSENSUS THAT TRACKS A
WEAK TROPOPAUSE FOLD FROM MISSOURI INTO NORTHERN OHIO THROUGH
MONDAY WOULD FAVOR A SWATH OF HEAVIER RAINFALL JUST AHEAD OF SAID
CORRIDOR. THIS WEAK FOLD IS LIKELY RESPONSIBLE FOR THE STRONG MID-
LEVEL FRONTOGENESIS NOTED ON THE MODELS.
GIVEN SAID SETUP...QPF GRIDS WERE INCREASED PRIMARILY FROM
ZANESVILLE TO MERCER COUNTY OR SO. THE MODEL CONSENSUS FAVORS THIS
FARTHER WEST QPF AXIS...WHILE THE GFS PREFERS A FARTHER EAST
PLACEMENT. HOWEVER...GIVEN THE TRACK OF THE UPPER LEVEL
FIELDS...THE GFS POSITIONING FAILS THE SANITY TEST AT THIS TIME.
OTHER THAN MAINLY QPF AND SLIGHT POP ADJUSTMENTS THIS
EVENING...THE REST OF THE FORECAST FEATURES STEADY/RISING
TEMPERATURES WITH THE NORTHWARD SLOSH OF THE WARM FRONT STILL
SEEMS ON TRACK. FRIES
PREVIOUS DISCUSSION FOLLOWS...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH MOVING FROM
THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE UPPER OHIO
VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS FEATURE. AT THE
SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE MOVING ACROSS THE
UPPER MIDWEST AND ANOTHER ACROSS THE MISSOURI VALLEY. THE FRONTAL
BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION BETWEEN A WARM
AND MOIST AIR MASS AHEAD OF IT AND ARCTIC AIR BUILDING IN BEHIND
IT. A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN LOW
ACROSS SOUTHERN OHIO AND INTO CENTRAL WV. LOCALLY...THE NEXT WAVE
IS RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING AS IT
PUSHES INTO EASTERN OHIO AND NORTH-CENTRAL WV.
THIS EVENING...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS ASSOCIATED WITH THE SHORT WAVE IS CURRENTLY
MOVING INTO THE AREA WILL SLIDE NORTHEASTWARD WITH THE WARM FRONT
AND PUSH INTO WESTERN PA. MESOSCALE MODELS ARE SUPPORTIVE OF THIS
FEATURE MOVING THROUGH MOST OF THE AREA BY LATE EVENING...AND THUS
POPS INCREASE TO CATEGORICAL.
TEMPS WILL BE SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM WITH A WARM
SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER 21Z.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. ITS WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH
WILL BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS
AND SHOWERS AHEAD OF THE COLD FRONT MOVING IN FROM THE
WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF THE
OVERNIGHT. TEMPS WILL REMAIN INCREASE A FEW DEGREES OVERNIGHT IN
WAA...WITH LOWS RANGING FROM THE MID 50S IN NORTH- CENTRAL WV TO
THE LOWER 30S NORTH OF THE I-80 CORRIDOR.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
GFS/NAM/ECMWF ARE IN AGREEMENT THAT THE MID-LEVEL TROUGH WILL
DE-AMPLIFY AS IS SLIDES EASTWARD ACROSS THE GREAT LAKES AND PUSHES A
COLD FRONT ACROSS THE UPPER OHIO VALLEY ON MONDAY. A MODEL CONSENSUS
OF THE EQUIVALENT POTENTIAL TEMPERATURE GRADIENT INDICATES A COLD
FRONT JUST NORTHWEST OF THE PITTSBURGH METRO AROUND 18Z ON MONDAY.
AHEAD OF THE FRONT...H5 VORTICITY INDICATES ENERGY IN WAA THAT WILL
ALLOW FOR SCATTERED SHOWERS AHEAD OF THE FRONT. A WELL-DEFINED
SURFACE TROUGH ASSOCIATED WITH THE COLD FRONT ALONG WITH THE STRONG
THERMAL GRADIENT ALONG THE FRONT WILL ALSO PROVIDE SUFFICIENT
FORCING FOR SHOWERS ALONG AND BEHIND THE FRONT. WITH THIS IN
MIND...CATEGORICAL POPS ARE FORECAST ACROSS THE MAJORITY OF THE AREA
THROUGH 21Z. WITH THE STRENGTH OF THE FRONT...VERY WEAK
INSTABILITY...AND STRONG SHEAR IN PLACE...HAVE INCLUDED A SCHC
THUNDER MENTION LATE MONDAY MORNING INTO THE EARLY AFTERNOON.
AHEAD OF THE FRONT...ONGOING WAA WILL ALLOW TEMPS TO BE IN THE UPPER
50S ACROSS MANY LOCATIONS WITH EVEN TEMPS NEAR 60 POSSIBLE IN
NORTH-CENTRAL WV.
CAA WILL ENSUE ACROSS THE ENTIRE AREA BY 00Z TUESDAY AS THE FRONT
SHIFTS SOUTHEAST OF THE AREA. WITH STRONG CAA...850MB TEMPS WILL
COOL TO AROUND 6-8C BY 12Z TUESDAY. 1000-500MB THICKNESS LINE DROPS
SOUTHEASTWARD QUICKLY OVERNIGHT AND IN RETURN...ANY LINGERING RAIN
SHOWERS WILL TURN TO SNOW SHOWERS BEHIND THE FRONT. SNOW
ACCUMULATION WILL BE LIGHT...WITH A DUSTING IN MOST LOWLAND
LOCATIONS AND UP TO AN INCH POSSIBLE ACROSS THE EASTERN RIDGES. LOWS
ON MONDAY NIGHT WILL ARE NOT FAR FROM A MAV/MET BLEND...IN THE UPPER
20S TO LOWER 30S ACROSS THE AREA.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM
THE SOUTHWEST ON TUESDAY. A COLD WEST-NORTHWESTERLY 850MB FLOW WILL
ALLOW FOR THE CHANCE OF SNOW SHOWERS TO LINGER INTO THE EARLY
AFTERNOON FOR LOCATIONS NORTH AND EAST OF PITTSBURGH. 850MB FLOW
THEN BACKS TO MORE SOUTHWESTERLY AND WILL ALLOW FOR DECREASING CLOUD
COVERAGE TUESDAY NIGHT. AS THE HIGH MOVES OVER THE AREA ON
WEDNESDAY...MORE ABUNDANT SUNSHINE IS ANTICIPATED. WITH THE CORE OF
THE COOLEST AIR ACROSS THE AREA ON TUESDAY...HIGHS WILL BE AROUND A
FEW DEGREES BELOW NORMAL...STRUGGLING TO REACH 40. CLEARING SKIES
TUESDAY NIGHT WILL ALLOW FOR SOME RADIATIONAL COOLING...WITH LOWS IN
THE LOW TO MID 20S ACROSS THE AREA. MORE SUNSHINE WEDNESDAY WILL
CONTRIBUTE TO HIGHS NEAR SEASONAL VALUES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON A QUIET START TO THE LONG RANGE WITH A SURFACE RIDGE
AXIS EXTENDING FROM NEW ENGLAND TO THE LOWER MISSISSIPPI VALLEY
DOMINATING THROUGH FRIDAY NIGHT. THIS WILL BRING DRY AND A BIT ABOVE
AVERAGE TEMPERATURES.
BY LATER SATURDAY A DEVELOPING STORM SYSTEM ACROSS THE CENTRAL
PLAINS WILL BEGIN TO SPREAD MOISTURE ACROSS THE OHIO VALLEY WITH
SHOWERS INCREASING AND CONTINUING SUNDAY AS LOW PRESSURE HEADS TO
THE WESTERN GREAT LAKES. ALL RAIN EXPECTED WITH THIS SYSTEM WITH
TEMPERATURES WELL ABOVE NORMAL.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
OCNL RAIN SHWRS WILL CONT OVNGT AS WARM AIR ADVCTN OCCURS AHD OF
ADVCG CDFNT. CIGS AND VSBYS WILL FALL INTO MVFR/IFR CATEGORIES AT
TIMES...IF NOT LWR WITH ABUNDANT LOW-LVL MSTR. SPCLY LATE TNGT...
MDT-HVY SHWRS WILL FORM ALONG CDFNT BNDRY IN ERN OH. RAIN SHWRS
XPCD TO IMPACT ALL TERMINALS ON MON AS BNDRY MOVES EWD ACRS RGN.
EARLY TMW EVE...ANY LINGERING PCPN WILL CHG TO SNOW BFR ENDING.
ACCUMS...IF ANY...WILL BE QUITE LMTD. A RAPID END TO ANY PCPN XPCD
MON NGT.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
PCPN SHOULD BE OVER BY TUE MRNG. VFR CONDS AMID HIPRES WILL
PERSIST THRU FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
UPDATE...KRAMAR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
746 PM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE TRACKS FROM THE OHIO VALLEY TO THE EASTERN GREAT LAKES
TONIGHT...AS A WARM FRONT LIFTS VERY SLOWLY NORTH THROUGH THE MID
ATLANTIC. A COLD FRONT APPROACHES FROM THE WEST MONDAY AND MOVES
THROUGH THE AREA MONDAY NIGHT AND OFF THE COAST TUESDAY. LOW
PRESSURE DEVELOPS ALONG THE FRONT TUESDAY NIGHT AND TRACKS OFF THE
COAST WEDNESDAY. HIGH PRESSURE BUILDS ACROSS THE REGION THURSDAY AND
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE LATEST SURFACE ANALYSIS INDICATES A FRONTAL BOUNDARY ALIGNED
ROUGHLY ALONG A LINE FROM THE PRINCE EDWARD/LUNENBURG
BORDER...THROUGH PTB ACROSS THE MOUTH OF THE YORK RIVER...AND
THROUGH THE FAR SOUTHERN TIP OF THE DELMARVA. S OF THE
BOUNDARY...THE SKY IS PARTLY TO MOSTLY CLOUDY WITH MILD
TEMPERATURES RANGING FROM THE MID 60S TO AROUND 70 ALONG WITH
DEWPOINTS IN THE UPPER 50S TO AROUND 60. N OF THE BOUNDARY...LOW
STRATUS PREVAILS WITH PERSISTENT FOG FROM THE NORTHERN NECK INTO
THE EASTERN SHORE...AND MOST WIDESPREAD ALONG THE ATLANTIC COAST
OF THE EASTERN SHORE WHERE AREAS OF DRIZZLE ARE ALSO OCCURRING
ALONG THE IMMEDIATE COASTLINE. A FEW SHOWERS CONTINUE TO MOVE ENE
ACROSS THE AREA DUE WEAK MID-LEVEL FORCING AND
INSTABILITY...ALTHOUGH THIS ACTIVITY IS EXPECTED TO DISSIPATE OVER
THE NEXT FEW HOURS. HAVE ADDED DENSE FOG NORTH OF THE FRONTAL
BOUNDARY AS MANY AREAS NOW HAVE VISIBILITY LESS THAN ONE QUARTER
MILE. ALSO LOOKING AT THE RAP AND LOCAL WRF MODEL ON BUFKIT SHOW
DECENT WARM ADVECTION AT 950 MB CAUSING A STEEP INVERSION WHICH
SHOULD KEEP THE LOW LEVEL MOISTURE TRAPPED UNTIL MID MORNING.
ALOFT PER WATER VAPOR IMAGERY...BROAD DEEP LAYER WSW FLOW PREVAILS
OVER THE MID ATLANTIC AND SOUTHEAST AHEAD OF A LONGWAVE TROUGH OVER
CANADA AND THE NORTH CENTRAL US. LOW PRESSURE IS DEVELOPING OVER THE
OHIO VALLEY AHEAD OF A POTENT SHORTWAVE TROUGH OVER THE UPPER
MIDWEST. THIS LOW TRACKS NORTHEAST TO THE EASTERN GREAT LAKES
OVERNIGHT. THE MAIN FORCING WILL REMAIN NORTH OF THE LOCAL AREA
HENCE THERE WILL BE NO STRONG MECHANISM TO SCOUR OUT THE LOW-LEVEL
MOISTURE AND PULL THE FRONT NORTHWARD. THE FRONT IS EXPECTED TO
REMAIN NEARLY STATIONARY OVERNIGHT. HAVE A WEAK PV MAX MOVING
NORTHEAST IN THE MID LEVEL SOUTHWEST FLOW ACROSS THE SOUTHEAST
PART OF THE AREA AROUND SUNRISE. MOST MODELS NOW SHOWING SOME
LIGHT RAIN WITH THIS FEATURE SO KEEPING CHANCE POPS OVER SOUTHEAST
AREAS AROUND SUNRISE. TEMPERATURES SHOULD BE STEADY IN THE LOW TO MID 50S
N OF THE FRONT AND FALL INTO THE MID TO UPPER 50S S OF THE FRONT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THE TROUGH OVER THE PLAINS LIFTS NORTH OF THE GREAT LAKES MONDAY.
MEANWHILE...ANOTHER TROUGH RACES FROM THE SOUTHERN PLAINS (LATE
TONIGHT) TO THE OHIO VALLEY MONDAY EVENING. THIS WILL PUSH A COLD
FRONT TO THE MOUNTAINS AND SHOULD FINALLY PULL THE WARM FRONT NORTH
OF THE AREA. AT THIS POINT WILL REMAIN RATHER PESSIMISTIC WITH
RESPECT TO CLEARING MONDAY MORNING...BUT WILL CONTINUE WITH HIGHS IN
THE MID 60S TO LOW 70S DUE TO A MILD START TO THE DAY. SLIGHT
CHANCE/LOW CHANCE POPS WILL BE FORECAST THROUGH THE DAY WITH MOIST
SOUTHERLY FLOW...ALTHOUGH ANY OF THIS ACTIVITY SHOULD BE LIGHT WITH
A LACK OF LARGE SCALE FORCING.
THE TROUGH WEAKENS AS IT MOVES ACROSS THE NORTHERN MID ATLANTIC
MONDAY NIGHT AND TUESDAY DRAGGING THE COLD FRONT THROUGH THE CWA AND
OFF THE COAST EARLY TUESDAY MORNING. LIKELY POPS WILL BE MAINTAINED
WITH THE FRONTAL PASSAGE ALTHOUGH QPF WILL BE LIGHT. LOWS MONDAY
NIGHT SHOULD BE IN THE MID 40S NW...TO MID 50S SE...FOLLOWED BY
HIGHS TUESDAY IN THE LOW 50S N AND W...TO LOW 60S SE.
THE FRONT STALLS OFF THE COAST TUESDAY NIGHT AND WEDNESDAY.
NUMERICAL MODELS DEVELOP A WAVE OF LOW PRESSURE ALONG THE
BOUNDARY...BUT DISAGREE WITH RESPECT TO TRACK. AT THIS POINT THE
09/12Z GFS SEEMED A REASONABLE COMPROMISE BETWEEN THE STRONGER AND
FARTHER WEST NAM AND FARTHER EAST ECMWF. SKY COVER WAS INCREASED AND
CHANCE POPS WERE INCLUDED FOR SE VA AND NE NC. LOW TEMPERATURES
TUESDAY NIGHT ARE FORECAST TO BE IN THE MID 30S N...TO LOW TO MID
40S SE...FOLLOWED BY HIGHS WEDNESDAY IN THE MID 40S TO LOW 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
FNTL BNDRY/ASSOCD MSTR SLO TO EXIT THE CST WED NGT. AFT THAT...HI
PRES BUILDS INTO THE MDATLC RGN FM THU THROUGH FRI...THEN WEAKENS
INTO THE NEXT WKND. UNCERTAINTY EXISTS NEXT SAT/SUN WRT PTNTL BKDR
CDFNT ENTERING THE RGN FM THE N...AND PSBL ARRIVAL OF LO PRES FM THE
W.
LO POPS WED NGT...GIVING WAY TO DRY WX (AND POPS AOB 14%) THU INTO
SAT. WILL BRING A GRADUAL INCRS IN CLDNS AND POPS FM SAT THROUGH
SUN. TEMPS WILL AVG OUT NR SEASONABLE LVLS THROUGH THE PD.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
WIDESPREAD LIFR/IFR/MVFR CONDS ACROSS THE REGION WITH A WEAK
FRONTL BNDRY JUST SOUTH OF RIC. WINDS ARE GNRLY N-NE NORTH OF THE
BNDRY AND SE-S TO THE SOUTH OF THE FRONT. GUIDANCE SHOWS FRONT
MOVG BACK NORTH EARLY MON AM AND BEING N OF THE REGION BY
AFTN/EARLY EVENING. EXPECT TO SEE IMPROVIG CONDS AND CIGS/FOG
LIFTING AND PSBL VFR BY EARLY/MID AFTN.
OUTLOOK...GOOD CHC FOR SHOWERS LATE MONDAY AND TUESDAY WITH
PERIODS OF MVFR/IFR LIKELY TO CONTINUE IN PRECIP.
&&
.MARINE...
FNTL BNDRY RMNS E-W ACRS THE CENTER OF THE CSTL WTRS THIS AFTN...W/
MNLY E WNDS N OF THE BNDRY...SSW S OF THE BNDRY. THE BNDRY WILL LIFT
BACK N AS WARM FRONT TNGT AS LO PRES TRACKS INTO THE LWR LAKES RGN.
WNDS BECOMING S...AND INCRSG (GRADUALLY) THROUGH THE OVRNGT...THOUGH
XPCD TO RMN JUST BLO SCA. AHD OF APPROACHING CDFNT FM THE W ON
MON...SSW WNDS AVG 10-20 KT...AND BY EVE XPCG SPEEDS ON THE BAY TO
BE AT MARGINAL SPDS FOR SCA. ALSO...SEAS ON THE OCN N OF CAPE
CHARLES XPCD TO GRADUALLY BUILD TO ABT 5 FT TWD EVE. CDFNT CROSSES
THE WTRS MON NGT...FOLLOWED BY LLVL SURGE AND MDT PROB FOR SCA SPDS
AS WNDS SWING TO NNW AFT MDNGT. CONDS TO SLOLY WANE DURG TUE AS FNT
STALLS JUST OF THE WTRS (INFO CSTL CAROLINAS) AND WK HI PRES BUILDS
IN THE NRN MDATLC RGN. PD OF NNE WNDS FM TUE NGT INTO WED NGT AS SFC
LO PRES DVLPS/TRACKS NE ALG THE STALLLED FNT. SPDS XPCD TO
INCRS...ESP SRN PORTION OF THE BAY/OCN WTRS TUE NGT INTO WED...ALG
W/ CORRESPONDING BUILDING WAVES/SEAS. BOTH 12Z/09 ECMWF/GFS AGREE
THAT HI PRES TO RETURN LT WK RESULTING IN BETTER MARINE WX CONDS
(HEADING INTO NEXT WKND).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...DENSE FOG ADVISORY UNTIL 9 AM EST MONDAY FOR MDZ021>025.
NC...NONE.
VA...DENSE FOG ADVISORY UNTIL 9 AM EST MONDAY FOR VAZ048-049-
062>064-071>078-083>086-099-100.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM MONDAY TO NOON EST TUESDAY FOR
ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 4 PM MONDAY TO 10 AM EST TUESDAY FOR
ANZ632-634.
SMALL CRAFT ADVISORY FROM 4 PM MONDAY TO 6 AM EST TUESDAY FOR
ANZ630-631.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/JAB
SHORT TERM...AJZ
LONG TERM...ALB
AVIATION...DAP/JEF
MARINE...ALB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
533 AM EST SAT DEC 8 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE CENTERS MOVING NORTHEASTWARD ALONG A
STALLED FRONT WILL CONTINUE TO PROVIDE THE UPPER OHIO VALLEY WITH
MILD TEMPERATURES AND PERIODS OF RAIN INTO MONDAY. EXPECT A COOL
DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT SURFACE AND RADAR DATA SHOW THE BATCH OF RAIN WILL HAVE EXITED
EAST PAST THE MOUNTAINS BY 7 AM. ANY LINGERING LOW VISIBILITY IN FOG
PATCHES NORTH WILL HAVE DISSIPATED BY THEN ALSO AS SURFACE WINDS
HAVE SLIGHTLY INCREASED TO 5 KTS.
RECENT RAP MODEL OUTPUT CONTINUES TO SHOW ANOTHER BATCH OF RAIN
SHOWERS CAN PASS EASTWARD ACROSS THE THE UPPER OHIO VALLEY DURING
TODAY. SO HAVE MENTIONED SCATTERED SHOWERS. HOWEVER ONCE THE LOW
PRESSURE CENTER FROM OHIO PASSES NORTHEASTWARD THROUGH LAKE ERIE
MIDDAY...RAIN SHOWERS WILL DECREASE IN COVERAGE WEST TO EAST THIS
AFTERNOON...LEAVING DRY CONDITIONS FOR MUCH OF TONIGHT.
PER BLEND OF RECENT GFS AND NAM MOS ALONG WITH GFS LAMP AND RAP
MODEL OUTPUT...FORECASTED TEMPERATURES TO CLIMB TO HIGHS THIS
AFTERNOON AT LEAST 15 DEGREES WARMER THAN NORMAL. POST SYSTEM
NORTHERLY WINDS TONIGHT WILL PROMOTE LOWS MORE THAN 10 DEGREES
COOLER THAN LAST NIGHT...BUT STILL ABOUT 10 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
CONCUR WITH RECENT SREF MODEL OUTPUT WITH DETAILS FROM NAM AND
WRF-NMM MODELS THAT THERE WILL BE ANOTHER SURGE OF RAIN SPREADING
NORTHEASTWARD ACROSS THE UPPER OHIO VALLEY DAYTIME SUNDAY AND
SUNDAY NIGHT. THIS RAIN SURGE WILL BE ASSOCIATED WITH A LOW
PRESSURE CENTER MOVING NORTHEASTWARD FROM MISSOURI.
ONCE THE LOW PRESSURE CENTER PASSES NORTHEASTWARD THROUGH LAKE
ERIE MONDAY MORNING...THE RAIN WILL TAPER TO SHOWERS. COLDER
POSTFRONTAL AIR WILL CAN CAUSE TEMPERATURES TO FALL MONDAY
AFTERNOON. LINGERING SHOWERS MONDAY NIGHT CAN TURN TO LIGHT SNOW
SHOWERS BEFORE ENDING LATE. TUESDAY SHOULD CONTINUE TO BE MAINLY
CLOUDY DUE TO ENSUING COLD POOL.
FORECASTED TEMPERATURES TO BE CONSIDERABLY WARMER THAN NORMAL
SUNDAY INTO MONDAY MORNING...THEN COOL DOWN TO SEASONABLE VALUES
MONDAY NIGHT AND TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
GFSE/ECMWF AGREE THAT HIGH PRESSURE WILL BUILD OVER THE AREA FROM
THE SOUTHWEST TUESDAY NIGHT AND WEDNESDAY. THAT FEATURE...ALONG
WITH A DEEP LAYER OF DRY AIR...WILL KEEP THE FORECAST DRY THROUGH
FRIDAY.
TEMPS THROUGH THE MID-WEEK WILL BE NEAR SEASONAL VALUES IN
THE COOLER AIR MASS BEHIND THE FRONT. READINGS ARE EXPECTED TO
MODERATE TO AROUND 5 DEGREES ABOVE NORMAL BY THE END OF THE WEEK
AS FLOW ALOFT BECOMES MORE SOUTHWESTERLY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
WITH A BREAK IN PRECIPITATION AND WINDS PICKING UP FROM THE
SW...CEILINGS HAVE CLIMBED FROM LIFR/IFR AT MOST LOCATIONS TO MVFR.
CONSIDERING UPSTREAM OBSERVATIONS...APPEARS THAT EVEN IF RAIN
MOVES BACK INTO THE AREA DURING THE LATE MORNING AND EARLY
AFTERNOON HOURS...THERE IS A GOOD CHANCE THAT CONDITIONS WILL NOT
DROP BACK TO IFR LEVELS. EXPECT THAT SHOWERS WILL BE MORE
SCATTERED IN COVERAGE TODAY THAN YESTERDAY...WITH THE BEST CHANCE
TO THE SOUTH AND EAST OF PITTSBURGH.
THE REGION MAY GO COMPLETELY DRY TONIGHT...ALTHOUGH MVFR CIGS
WILL REMAIN. NEXT ROUND OF SHOWERS SHOULD HOLD OFF UNTIL
SUNDAY...ALTHOUGH THIS RAIN WILL BE INCLUDED IN THE 30 HOUR
PITTSBURGH TAF.
.OUTLOOK.../SUNDAY THROUGH WEDNESDAY/...
NEXT LOW PRESSURE SYSTEM WILL CAUSE RESTRICTIONS THROUGH TUESDAY
BEFORE COLD FRONT MOVES OUT OF THE REGION AND VFR CONDITIONS FINALLY
RETURN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
452 AM EST SAT DEC 8 2012
.SYNOPSIS...
A SERIES OF LOW PRESSURE CENTERS MOVING NORTHEASTWARD ALONG A
STALLED FRONT WILL CONTINUE TO PROVIDE THE UPPER OHIO VALLEY WITH
MILD TEMPERATURES AND PERIODS OF RAIN INTO MONDAY. EXPECT A COOL
DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT SURFACE AND RADAR DATA SHOW THE BATCH OF RAIN HAS BEGUN TO
EXIT EAST PAST THE MOUNTAINS. SURFACE WINDS HAVE SLIGHTLY
INCREASED TO 5 KTS...AND THIS HAS HELPED VISIBILITIES IN FOG
IMPROVE OVER MUCH OF THE UPPER OHIO VALLEY. SO ONLY CONTINUED
MENTION OF PATCHY FOG THROUGH DAYBREAK NORTH.
WITH RECENT RAP MODEL OUTPUT CONTINUING TO SHOW ANOTHER SURGE OF
RAIN MOVING ACROSS THE UPPER OHIO VALLEY DURING TODAY...HAVE CONTINUED
MENTION OF RAIN. HOWEVER ONCE THE LOW PRESSURE CENTER FROM OHIO
PASSES NORTHEASTWARD THROUGH LAKE ERIE MIDDAY...RAIN WILL DECREASE
IN COVERAGE WEST TO EAST THIS AFTERNOON...LEAVING DRY CONDITIONS
FOR MUCH OF TONIGHT.
PER BLEND OF RECENT GFS AND NAM MOS ALONG WITH GFS LAMP AND RAP
MODEL OUTPUT...FORECASTED TEMPERATURES TO CLIMB TO HIGHS THIS
AFTERNOON AT LEAST 15 DEGREES WARMER THAN NORMAL. POST SYSTEM
NORTHERLY WINDS TONIGHT WILL PROMOTE LOWS MORE THAN 10 DEGREES
COOLER THAN THIS OVERNIGHT BUT STILL ABOUT 10 DEGREES ABOVE
NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
CONCUR WITH RECENT SREF MODEL OUTPUT WITH DETAILS FROM NAM AND
WRF-NMM MODELS THAT THERE WILL BE ANOTHER SURGE OF RAIN SPREADING
NORTHEASTWARD ACROSS THE UPPER OHIO VALLEY DAYTIME SUNDAY AND
SUNDAY NIGHT. THIS RAIN SURGE WILL BE ASSOCIATED WITH A LOW
PRESSURE CENTER MOVING NORTHEASTWARD FROM MISSOURI.
ONCE THE LOW PRESSURE CENTER PASSES NORTHEASTWARD THROUGH LAKE
ERIE MONDAY MORNING...THE RAIN WILL TAPER TO SHOWERS. COLDER
POSTFRONTAL AIR WILL CAN CAUSE TEMPERATURES TO FALL MONDAY
AFTERNOON. LINGERING SHOWERS MONDAY NIGHT CAN TURN TO LIGHT SNOW
SHOWERS BEFORE ENDING LATE. TUESDAY SHOULD CONTINUE TO BE MAINLY
CLOUDY DUE TO ENSUING COLD POOL.
FORECASTED TEMPERATURES TO BE CONSIDERABLY WARMER THAN NORMAL
SUNDAY INTO MONDAY MORNING...THEN COOL DOWN TO SEASONABLE VALUES
MONDAY NIGHT AND TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
GFSE/ECMWF AGREE THAT HIGH PRESSURE WILL BUILD OVER THE AREA FROM
THE SOUTHWEST TUESDAY NIGHT AND WEDNESDAY. THAT FEATURE...ALONG
WITH A DEEP LAYER OF DRY AIR...WILL KEEP THE FORECAST DRY THROUGH
FRIDAY.
TEMPS THROUGH THE MID-WEEK WILL BE NEAR SEASONAL VALUES IN
THE COOLER AIR MASS BEHIND THE FRONT. READINGS ARE EXPECTED TO
MODERATE TO AROUND 5 DEGREES ABOVE NORMAL BY THE END OF THE WEEK
AS FLOW ALOFT BECOMES MORE SOUTHWESTERLY.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
RAIN AND FOG WILL PREVAIL TONIGHT AT ALL TERMINALS WITH IFR CONDITIONS.
WINDS WILL BE MAINLY FROM THE SOUTH/SOUTHEAST AT LESS THAN 5 KTS.
AS FRONTAL BOUNDARY SLOWLY PUSHES SOUTHEAST SATURDAY AFTERNOON...IFR
CEILINGS BEGINNING AT WESTERN TERMINALS WILL LIFT TO MVFR CONDITIONS
THROUGH THE EVENING.
.OUTLOOK.../SUNDAY THROUGH WEDNESDAY/...
NEXT LOW PRESSURE SYSTEM WILL CAUSE RESTRICTIONS THROUGH TUESDAY
BEFORE COLD FRONT MOVES OUT OF THE REGION AND VFR CONDITIONS FINALLY
RETURN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
138 AM EST SAT DEC 8 2012
.SYNOPSIS...
A STATIONARY FRONT WILL BE THE FOCUS FOR PERIODIC RAIN ACROSS THE
UPPER OHIO VALLEY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
PER RECENT SURFACE AND RADAR DATA HAVE CONTINUED MENTION OF RAIN
AND PATCHY FOG ACROSS THE UPPER OHIO VALLEY UNTIL EARLY MORNING.
FORECASTED TEMPERATURES TO BE NEARLY STEADY THE REST OF TONIGHT.
BLEND OF RECENT RAP NAM AND WRF-NMM SHOW THAT HAS THE LOW
PRESSURE CENTER FROM INDIANA PASSES NORTHEASTWARD THROUGH
NORTHWESTERN PENNSYLVANIA DURING MIDDAY...RAIN WILL DECREASE IN
COVERAGE WEST TO EAST THIS AFTERNOON. CONCUR WITH CONSENSUS OF
SREF MODEL MEMBERS THAT THERE CAN EVEN BE A DRY BREAK EARLY
TONIGHT.
THEN EXPECT A SURGE OF RAIN TO SPREAD NORTHEASTWARD INTO THE UPPER
OHIO VALLEY LATE TONIGHT...AHEAD OF THE NEXT LOW PRESSURE CENTER
TRAVELING EASTWARD ALONG THE STATIONARY FRONT SITUATED NEAR THE
MASON-DIXON LINE.
PER BLEND OF RECENT GFS AND NAM MOS ALONG WITH GFS LAMP AND RAP
MODEL OUTPUT...FORECASTED TEMPERATURES TO CLIMB TO HIGHS THIS
AFTERNOON AT LEAST 15 DEGREES WARMER THAN NORMAL. POST SYSTEM
NORTHERLY WINDS TONIGHT WILL PROMOTE LOWS MORE THAN 10 DEGREES
COOLER THAN THIS OVERNIGHT BUT STILL ABOUT 10 DEGREES ABOVE
NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A SMALL BUBBLE OF HIGH PRESSURE IS FORECAST TO BUILD OVER THE
REGION FROM THE EASTERN GREAT LAKES SATURDAY NIGHT...RESULTING IN
A GENERALLY DRY FORECAST...WITH EXCEPTION FOR ISOLATED SHOWERS
WHICH MAY STILL BE POSSIBLE MAINLY ACROSS THE RIDGES.
BY SUNDAY...THE NEXT...AND STRONGER SHORTWAVE IS PROJECTED TO BRING
THE FRONT NORTHWARD AND SPREAD MORE RAIN ACROSS THE REGION FROM
SOUTH TO NORTH.
THEREAFTER...THE AREA WILL REMAIN IN THE WARM SECTOR OF A GREAT
LAKES LOW PRES SYSTEM WITH OCCASIONAL RAIN AND QUITE MILD
TEMPERATURES.
ON MONDAY...THAT SYSTEMS COLD FRONT WILL TRAVERSE THE REGION
ACCOMPANIED BY RAIN AND FALLING AFTERNOON TEMPERATURES.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS ARE IN GENL AGREEMENT IN DEPICTIONS OF COLD FRONT PUSHING
SOUTHEAST OF THE AREA MONDAY NIGHT...WITH COLD AIR ADVECTION
CONTINUING THROUGH TUESDAY. THE ECMWF IS SLIGHTLY SLOWER WITH THE
FRONT AND THE FORECAST IS A BLEND OF THE ECMWF WITH THE FASTER
GFS/NAM AT THE START.
AS COLDER AIR FILTERS IN BEHIND THE FRONT...THE GFS AND ECMWF
THICKNESS REDUCTION SUPPORTS SNOW SHOWERS BEFORE PRECIPITATION
COMES TO AN END EARLY ON TUESDAY.
GFSE/ECMWF ALSO AGREE THAT HIGH PRESSURE WILL BUILD OVER THE AREA
FROM THE SOUTHWEST TUESDAY NIGHT AND WEDNESDAY. THAT FEATURE...ALONG
WITH A DEEP LAYER OF DRY AIR...WILL KEEP THE FORECAST DRY THROUGH
FRIDAY. TEMPS THROUGH THE MID-WEEK WILL BE NEAR SEASONAL VALUES IN
THE COOLER AIR MASS BEHIND THE FRONT. READINGS ARE EXPECTED TO
MODERATE TO AROUND 5 DEGREES ABOVE NORMAL BY THE END OF THE WEEK
AS FLOW ALOFT BECOMES MORE SOUTHWESTERLY.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
RAIN AND FOG WILL PREVAIL TONIGHT AT ALL TERMINALS WITH IFR CONDITIONS.
WINDS WILL BE MAINLY FROM THE SOUTH/SOUTHEAST AT LESS THAN 5 KTS.
AS FRONTAL BOUNDARY SLOWLY PUSHES SOUTHEAST SATURDAY AFTERNOON...IFR
CEILINGS BEGINNING AT WESTERN TERMINALS WILL LIFT TO MVFR CONDITIONS
THROUGH THE EVENING.
.OUTLOOK.../SUNDAY THROUGH WEDNESDAY/...
NEXT LOW PRESSURE SYSTEM WILL CAUSE RESTRICTIONS THROUGH TUESDAY
BEFORE COLD FRONT MOVES OUT OF THE REGION AND VFR CONDITIONS FINALLY
RETURN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
342 PM EST SAT DEC 8 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
HIGH PRESSURE IS CURRENTLY LOCATED IN MANITOBA AND ONTARIO...WITH A
RIDGE STRETCHING SOUTHEAST INTO WESTERN UPPER MI AND WI. LIGHT
NORTHWEST FLOW...WITH RUC ANALYZED H850 OF -10 TO -12C...HAS LED TO
LAKE EFFECT CLOUDS AND LIGHT SNOW SHOWERS THROUGH THIS AFTERNOON IN
THE TRADITIONAL NORTHWEST FLOW LOCATIONS.
UPSTREAM...PV ANOMALY IN SRN SD AND NW NEBRASKA WILL SHIFT ENE
TONIGHT AND INTO MN BY 12Z SUNDAY...WITH THE SURFACE LOW FOLLOWING
SUIT. THIS ANOMALY WILL SHIFT NORTHEAST THROUGH WESTERN UPPER
MICHIGAN THROUGH THE DAY ON SUNDAY AND BE WEAKENING DUE TO INFLUENCE
OF SECOND ANOMALY ENTERING NORTHERN MN AND THE SOUTHERN WAVE
BECOMING MORE DOMINATE AS IT DIVES SOUTHEAST THROUGH THE CENTRAL
ROCKIES DURING THE DAY ON SUNDAY. THIS...COMBINED WITH A
STRENGTHENING JET OVER THE OHIO VALLEY ON SUNDAY...WILL ALLOW A
SECONDARY LOW TO DEVELOP IN THE OHIO VALLEY REGION DURING THE DAY
AND PRODUCE A BROAD AREA OF LOW PRESSURE WHICH TRANSITIONS THE LOW
OVER OUR AREA TO A TROUGH. STILL DIFFERENCES IN THE MODELS...BOTH
RUN-TO-RUN AND BETWEEN MODELS...WITH THE POTENTIAL WEAKENING/SPEED
OF THE PV ANOMALY AND THE LOCATION OF THE ASSOCIATED SURFACE TROUGH
HEADING INTO SUNDAY AFTERNOON/EVENING. LATEST TRENDS IN THE MODELS
ARE FOR A SLOWER MOVEMENT OF THE PV ANOMALY THROUGH UPPER MICHIGAN
ON SUNDAY...WHICH KEEPS THE SURFACE TROUGH AXIS OVER
NORTHERN/CENTRAL WISCONSIN.
TONIGHT...THE HIGH PRESSURE RIDGE EXITING TO THE NORTHEAST WILL
PRODUCE QUIET WEATHER BEFORE THE SYSTEM. UPSTREAM DRYING THIS
AFTERNOON HAS ATE AWAY AT SOME OF THE LAKE EFFECT CLOUDS OVER THE
WEST AND ONCE DAYTIME HEATING IS LOST...EXPECT THE SAME TO OCCUR
OVER THE INTERIOR LOCATIONS THIS EVENING. THIS CLEARING WILL MAKE
FOR TRICKY LOW TEMPERATURES TONIGHT AND FOLLOWED THE PREVIOUS SHIFT
BY TRENDED THEM DOWN A LITTLE MORE AS PWATS 65 PERCENT OF NORMAL
AND THERE ARE LIGHT WINDS. WENT WITH LOWS IN UPPER TEENS...BUT BASED
OFF HOW QUICKLY TEMPS FELL THIS MORNING IN CLEARING AREAS...THAT MAY
NOT BE COLD ENOUGH. OTHERWISE...MID/HIGH LEVEL CLOUDS WILL BE ON THE
INCREASE FROM THE SOUTHWEST WITH THE APPROACHING SYSTEM.
SUNDAY...PRECIPITATION BUILDS IN FROM SOUTHWEST TO NORTHEAST THROUGH
THE DAY. STARTING BETWEEN 12-15Z NEAR KIWD...LATE MORNING OR EARLY
AFTERNOON OVER THE CENTRAL...AND MID/LATE AFTERNOON OVER THE EAST.
WITH THE LATEST SLOWER TRENDS...HAVE DELAYED THE START A COUPLE OF
HOURS FROM THE PREVIOUS SHIFT. PLENTY OF COLD AIR ALOFT...SO EXPECT
PRECIPITATION TO BE AS ALL SNOW. AS FOR FORCING...BEST MID LEVEL WAA
IS FOCUSED OVER THE SOUTH CENTRAL AND NEAR LAKE MICHIGAN THROUGH
THE DAY. THIS LINES UP WITH WEAK FGEN BETWEEN H850-650 OVER THE AREA
FOR THE AFTERNOON...BUT SEEMS TO FOCUS OVER THE SOUTHEAST HALF OF
THE CWA LATE IN THE AFTERNOON. IN ADDITION...BROAD 280-290K
ISENTROPIC ASCENT WILL SPREAD OVER THE CWA DURING THE DAY.
FINALLY...H850 TEMPS AROUND -9C SHOULD FAVOR SOME LAKE ENHANCEMENT
FOR THE KEWEENAW AND ALSO FOR LOCATIONS NEAR LAKE MICHIGAN FAVORED
BY ESE WINDS.
WITH THE SLIGHT DELAY WITH THE SLOWER ARRIVAL OF THE PV ANOMALY AND
SURFACE TROUGH BEING A LITTLE FARTHER SOUTH...BEST PRECIPITATION
STRADDLES THE SHORT/LONG TERM TRANSITION. ALL IN ALL...MODEL QPF
FOR SUNDAY INTO SUNDAY NIGHT WITH THE SYNOPTIC FEATURES IS IN THE
0.25-0.4IN FOR MOST AREAS AND WHEN COMBINED WITH A SNOW RATIO AROUND
13-15 TO 1...WOULD PUT 3 TO 6 INCHES OF SYNOPTIC SNOW OVER THE
AREA THROUGH SUNDAY EVENING. OUTSIDE OF ANY LAKE ENHANCEMENT...THE
HIGHEST AMOUNTS SHOULD LINE UP ALONG THE WISCONSIN BORDER WITH THE
SLIGHT SOUTH SHIFT OF THE SURFACE TROUGH. THE LONG TERM DISCUSSION
WILL COVER THE BULK OF THE HEADLINES...BUT DID DROP THE WATCH OVER
THE WESTERN COUNTIES AND HAVE STARTED A LONGER PERIOD ADVISORY FROM
WEST TO EAST THROUGH THE DAY ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
MAIN CONCERN IS WITH SNOWFALL FORECAST FOR THE FIRST 24 HOURS OF THE
LONG TERM.
SUN NIGHT/MON...IN GENERAL...MODELS ARE IN GOOD AGREEMENT...BUT
THERE ARE SUBTLE VARIATIONS AT SMALLER SCALES THAT BECOME MAGNIFIED
IN THE SNOWFALL FORECAST. THE DIFFICULTY AND UNCERTAINTY IS DUE TO
THE FACT THAT THE SYSTEM OVER THE REGION SUN NIGHT WILL BE MERGING
WITH A SRN STREAM SYSTEM OVER THE OHIO VALLEY...PLUS THE FACT THAT
MODELS HAVE A HARD TIME CONSISTENTLY HANDLING THE PV ANOMALIES THAT
WILL DRIVE A GOOD PORTS OF THE SNOWFALL WITH THIS SYSTEM. LATEST
RUNS OF THE GFS/NAM/REGIONAL GEM/REGIONAL WRF ARE NOW IN BETTER
AGREEMENT IN BRINGING THE WEAKENING PRIMARY PV ANOMALY FROM NW WI AT
00Z MON TO CENTRAL UPPER MI AROUND 06Z MON...THEN SHEARING IT OUT
AND PUSHING IT NORTHEAST BY 12Z MON. MEANWHILE...THE SECONDARY PV
ANOMALY WILL ROTATE INTO CENTRAL/SRN WI...FARTHER S THAN PREVIOUS
RUNS OF THE MODELS. THE TIMING/LOCATION OF THE PV ANOMALIES IS
CONSISTENT WITH THE OVERALL TREND OVER THE LAST FEW RUNS OF THE
MODELS IN SLOWING THE SYSTEM DOWN AND MOVING IT FARTHER S. THE
RESULTING SFC TROUGH LOOKS TO STAY TO THE S OF THE CWA OVER
CENTRAL/NRN WI. LOW LEVEL FLOW WILL GENERALLY BE ELY AT 00Z MON WITH
850MB TEMPS AROUND -9C. BY 06Z MON...LOW LEVEL WINDS BACK TO MORE
ENE...THEN TO NNE BY 12Z MON AS 850MB TEMPS FALL TO -11C. SYNOPTIC
SNOWFALL AMOUNTS WILL BE HIGHEST OVER THE SRN HALF OF UPPER MI SUN
NIGHT...BUT THAT SHOULD BE OFFSET SOME BY UPSLOPE FLOW IN SOME NRN
LOCATIONS...PARTICULARLY NCENTRAL UPPER MI AND THE KEWEENAW...THEN
OVER THE WRN U.P. LATER SUN NIGHT. 850MB TEMPS FALL ANOTHER COUPLE
OF DEGREES THROUGH THE DAY MON WHILE FLOW BECOMES INCREASING
ANTICYCLONIC AS THE SFC TROUGH MOVES QUICKLY E AND A RIDGE MOVES
OVER WRN LAKE SUPERIOR BY 00Z TUE. THUS...EXPECT LES FROM NNW WINDS
MON MORNING...DIMINISHING THROUGH MON EVENING. WITH THIS TYPE OF
SYSTEM THERE IS INHERENT UNCERTAINTY THAT WILL PROBABLY NOT BE
RESOLVED UNTIL THE SYSTEM IS ON THE DOORSTEP OF THE CWA...SO
CONFIDENCE IN SNOWFALL AMOUNTS IS STILL SOMEWHAT LIMITED. STORM
TOTAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES IS EXPECTED...WITH SOME
LOCALLY HIGHER AMOUNTS POSSIBLE IN THE HIGHER TERRAIN OF WRN
GOGEBIC/ONTONAGON COUNTIES AND NW MARQUETTE/NE BARAGA COUNTIES.
DECIDED IN COORDINATION WITH SHORT TERM SHIFT TO ISSUE WINTER WX
ADVISORIES OVER THE ENTIRE CWA. COULD SEE SOME LOCATIONS GO SLIGHTLY
ABOVE ADVISORY CRITERIA...BUT NOT CONFIDENT ENOUGH IN THAT TO
JUSTIFY WARNING. ALSO...THE TIME THAT THE HEAVIEST SNOW WILL FALL
/SUN EVENING AND EARLY SUN NIGHT/ IS NOT A HIGH IMPACT TIME TRAVEL
WISE...PLUS THE FACT THAT THE STORM TOTAL WILL OCCUR OVER 24 HOURS
OR MORE. ALSO DECIDED ON THE ADVISORY WITH THE IDEA THAT IT WOULD BE
EASIER TO UPGRADE TO A WARNING IF NEEDED THAN HAVE TO CANCEL
WARNINGS AND ISSUE AN ADVISORY IF THE BORDERLINE WARNING AMOUNTS DO
NOT OCCUR...WHICH WOULD LEAD TO A MISSED EVENT FOR
VERIFICATION...SORT OF THE PATH OF LEAST REGRET.
A VERY WEAK SHORTWAVE TROUGH MOVES ACROSS THE AREA TUE INTO TUE
NIGHT...BRINGING SE FLOW OFF LAKE MICHIGAN FROM 12Z TUE INTO WED.
THIS SHOULD LEAD TO LES OFF LAKE MI INTO ERN UPPER MI...ESPECIALLY
SERN SCHOOLCRAFT COUNTY. INVERSION HEIGHTS SHOULD BE AROUND 10KFT
ACCORDING TO THE NAM/GFS WITH UNIDIRECTIONAL WINDS. THE RESULTING
LES BAND SHOULD BE A LARGER MORE DOMINANT ONE...BUT SHOULD ALSO NOT
STAY IN ONE PLACE TOO LONG AS WINDS STEADILY VEER. EVEN SO...MAY END
UP BEING CLOSE TO ADVISORY AMOUNTS. WINDS WILL BECOME WLY ENOUGH
BEHIND THE TROUGH BY 06Z WED TO BRING LES TO NW UPPER MI...BUT WINDS
QUICKLY BECOME ANTICYCLONIC BY 12Z WED AS A SFC RIDGE MOVES TO WRN
LAKE SUPERIOR...SO LIGHTER SNOW AMOUNTS ARE EXPECTED THERE.
A SLIGHTLY STRONGER SYSTEM WILL MOVE N OF THE AREA THU AND DRAW
WARMER TEMPS IN THE CWA...BUT NO SIGNIFICANT PRECIP IS EXPECTED.
HIGHS IN THE MID TO UPPER 30S SEEMS REASONABLE. PRETTY QUIET AFTER
THAT UNTIL MODELS INDICATE A MUCH STRONGER LOW PRESSURE SYSTEM
MOVING NEARBY ON SAT. MODELS ARE IN GOOD AGREEMENT FOR HOW FAR OUT
THE SYSTEM IS...SO WILL USE CONSENSUS OF MODELS FOR THE FORECAST
PAST TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM EST SAT DEC 8 2012
LINGERING LAKE EFFECT CLOUDS WILL AFFECT ALL THREE SITES THIS
AFTERNOON AND LEAD TO MVFR CONDITIONS. BUT AS A SURFACE HIGH
PRESSURE RIDGE MOVES IN...EXPECT DRIER AIR TO ARRIVE AND WINDS TO
TURN OUT OF THE SOUTHEAST THROUGH THE NIGHT. THIS SHOULD PUSH
CONDITIONS BACK TO VFR.
ATTENTION THEN TURNS TO LOW PRESSURE SYSTEM IN THE DAKOTAS THAT
WILL APPROACH THE AREA ON SUNDAY. MODELS ARE STILL STRUGGLING WITH
THE EXACT DETAILS...BUT LATEST RUNS HAVE SLOWED THE SYSTEM SOME AND
HAVE SHOWN A LATER ARRIVAL /TOWARDS AFTERNOON/ FOR SNOW AT
KCMX/KSAW. AT KIWD...SHOULD SEE THE SNOW START AROUND DAYBREAK AND
THEN REALLY INCREASE IN INTENSITY TOWARDS MID MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EST SAT DEC 8 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHWEST SOUTH DAKOTA WILL
ENTER MN TOMORROW MORNING AND THEN MERGE WITH A LOW DEVELOPING IN
THE GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS
TROUGH WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST
DIRECTION SUNDAY INTO SUNDAY NIGHT. AT THIS TIME...THINKING WINDS
WILL BE IN THE 20-30KT RANGE...ALTHOUGH THERE COULD BE A FEW GALE
FORCE GUSTS TO 35KTS OVER THE WEST AS THE TROUGH SHARPENS LATE
SUNDAY NIGHT. BEHIND THIS FEATURE...A SERIES OF WEAK RIDGES AND
TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST OF THE WORK WEEK
AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM SUNDAY TO 7 AM EST MONDAY FOR
MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ SUNDAY TO 7 AM
EST /6 AM CST/ MONDAY FOR MIZ001-003-004-010-084.
WINTER WEATHER ADVISORY FROM 1 PM SUNDAY TO 1 PM EST MONDAY FOR
MIZ005.
WINTER WEATHER ADVISORY FROM 7 AM EST /6 AM CST/ SUNDAY TO 5 PM
EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 9 AM SUNDAY TO 3 AM CST MONDAY FOR
MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...TITUS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
844 PM CST SUN DEC 9 2012
.UPDATE...
ISSUED AT 844 PM CST SUN DEC 9 2012
GOING FORECAST STILL LOOKS GOOD. SCT -SHRA HAS MOVED OUT OF THE
CWA AS THE COLD FRONT CONTINUES TO MOVE SOUTHEAST. BACK EDGE OF
LOW CLOUDS ARE MOVING INTO WESTERN CWA WITH A SECOND AREA OF LOW
CLOUDS MOVING IN QUICKLY BEHIND IT. RAP PROGS IS SHOWING ABUNDANT
AMOUNT OF LOW LEVEL MOISTURE STAYING IN THE AREA THROUGH MIDDAY
TOMORROW KEEPING SKIES MOSTLY CLOUDY THROUGH TOMORROW MORNING.
BRITT
&&
.SHORT TERM...
ISSUED AT 221 PM CST SUN DEC 9 2012
(TONIGHT)
PRIMARY CONCERN FOR TONIGHT WILL BE PRECIP CHANCES AND TEMPERATURES
BEHIND THE STRONG COLD FRONT THAT IS MOVING THROUGH THE REGION. THE
INITIAL WIND SHIFT IS ALREADY THROUGH THE NORTHWESTERN 2/3 OF THE
CWFA. WIND SHIFT SHOULD BE ALL THE WAY THROUGH OUR SOUTHEAST BORDER
WITH WFO PAH BY 00Z. UNTIL THEN...EXPECTING A CONTINUING THREAT FOR
THUNDERSTORMS ACROSS SOUTHEAST MO/SOUTHWEST IL. THUNDER THREAT
SHOULD DIMINISH AFTER FROPA AND ONLY EXPECT SHOWERS DURING THE
EVENING. WIND WILL BE INCREASING THROUGH THE EVENING BEHIND THE
FRONT AND GUSTS IN EXCESS OF 25KTS ARE LIKELY GIVEN THE STRONG
PRESSURE GRADIENT AHEAD OF THE 1035MB HIGH BUILDING ACROSS THE
PLAINS. WITH LOWS IN THE TEENS AND 20S IN THE COLD SECTOR THIS
MORNING ACROSS NEBRASKA...MOS FORECAST LOWS FOR TONIGHT IN THE 20S
LOOK VERY REASONABLE...AND WOULD NOT BE SURPRISED TO SEE IT GET
COLDER IN SOME SPOTS. WIND CHILL VALUES WILL BE A SLAP IN THE FACE
TOMORROW MORNING AFTER ALL THE MILD WEATHER WE`VE BEEN HAVING.
EXPECT READINGS IN THE SINGLE DIGITS TO MID TEENS.
CARNEY
&&
.LONG TERM...
ISSUED AT 221 PM CST SUN DEC 9 2012
(MONDAY AND MONDAY NIGHT)
EXPECT A COLD AND WINDY DAY WITH TEMPERATURES STRUGGLING TO RISE
BACK TO THE FREEZING MARK. IN FACT...LOOKING AT THE AIR MOVING IN
FROM THE NORTHWEST...MY FORECAST MAY STILL BE TOO WARM. WENT ON
COLDER SIDE OF GUIDANCE FOR MONDAY NIGHT AS RIDGE CENTER PROGRESSES
ACROSS THE CWA.
(TUESDAY THRU THURSDAY)
UPPER FLOW BECOMES MORE ZONAL DURING THIS PERIOD WITH A SHORTWAVE
PASSING TO OUR SOUTH ON WEDNESDAY. TEMPERATURES WILL MODERATE BACK
TO AND ABOVE NORMAL AS DRY WEATHER AND SOUTHWEST SURFACE WINDS ARE
ANTICIPATED.
(FRIDAY THRU SUNDAY)
UPPER FLOW WILL BECOME SOUTHWESTERLY BY WEEKS END AS A DEEP TROF
DIGS ACROSS THE WEST COAST. EVENTUALLY THIS TROF/LOW WILL CROSS THE
FOUR CORNERS REGION AND EJECT INTO THE PLAINS...WITH LEE
CYCLOGENESIS OCCURRING FRIDAY/FRIDAY NIGHT IN THE CENTRAL PLAINS.
HAVE IGNORED THE 12Z OPERATIONAL GFS AS IT DEAMPLIFIES THIS WAVE AS
IT MOVES EAST...TAKING THE SURFACE LOW DIRECTLY EAST WHICH SEEMS
UNREALISTIC AND INCONSISTENT WHEN COMPARED TO PREVIOUS RUNS AND
ENSEMBLE FORECASTS.
THE MORE CONSISTENT ECWMF MODEL SPINS THE SURFACE LOW UP ACROSS
SOUTHWEST KANSAS AND LIFTS IT NORTHEAST ACROSS NORTHWEST MISSOURI
...EASTERN IOWA...TOWARD THE WESTERN GREAT LAKES REGION. THIS PLACES
THE ENTIRE CWA IN THE WARM SECTOR OF THIS SYSTEM AND AM EXPECTING
ENOUGH RETURN FLOW FROM THE SOUTH FOR THUNDERSTORMS TO BE LIKELY
WITH THIS SYSTEM.
AIR BEHIND THIS SYSTEM APPEARS TO BE MORE PACIFIC...THAN
CANADIAN...SO ABOVE NORMAL TEMPERATURES SHOULD CONTINUE ON SUNDAY.
CVKING
&&
.AVIATION...
ISSUED AT 547 PM CST SUN DEC 9 2012
COLD FRONT HAS MOVED SE OF THE TAF SITES ALONG WITH ACCOMPANYING
SHOWERS. WINDS HAVE BECOME NWLY AT THE TAF SITES BEHIND THIS
FRONT AND WILL STRENGTHEN AND BECOME GUSTY AS THE SFC PRESSURE
GRADIENT TIGHTENS AS A STRONG SFC RIDGE OVER THE NRN PLAINS BUILDS
SEWD INTO MO. THESE RELATIVELY STRONG AND GUSTY NWLY SFC WINDS
WILL CONTINUE ON MON. CEILING HEIGHTS HAVE BEEN SLOWLY RISING INTO
THE MVFR CATAGORY AND WILL CONTINUE TO RISE THIS EVNG. THERE MAY
BE A BRIEF PERIOD OF VFR CONDITIONS LATER THIS EVNG AND INTO THE
OVERNIGHT HOURS PARTICULARLY AT COU...BUT MORE MVFR CIGS ACROSS
ERN NEBRASKA AND IA WILL ADVECT SEWD INTO THE AREA LATE TGT. FOR
NOW WILL KEEP MVFR CIGS IN THE TAFS UNTIL MON AFTN WHEN THE LOW
LEVEL CLOUD DECK SHOULD ADVECT E OF THE TAF SITES.
SPECIFICS FOR KSTL...VSBYS SHOULD BECOME UNRESTRICTED EARLY THIS
EVNG AS THE NWLY SFC WIND INCREASES AND BRINGS DRIER SFC AIR INTO
THE REGION. THE CEILING SHOULD ALSO GRADUALLY RISE INTO THE MVFR
CATAGORY. ALTHOUGH THERE MAY BE A BRIEF PERIOD OF VFR CONDITIONS
LATER THIS EVNG INTO THE OVERNIGHT HOURS...WILL KEEP THE MVFR
CIGS GOING IN THE STL TAF TGT AND MUCH OF MON AS THE SATELLITE
LOOP SHOWS MORE MVFR CIGS DROPPING SEWD TOWARDS STL AND THE MODELS
DEPICT HIGH RELATIVE HUMIDITY VALUES AROUND 2000-4000 FT LATE TGT
UNTIL EARLY MON AFTN. THE MVFR CLOUD DECK SHOULD SCATTER OUT LATE
MON AFTN...AND THE SFC WIND SHOULD DIMINISH MON EVNG AS THE SFC
PRESSURE GRADIENT RELAXES.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
324 AM MST SAT DEC 8 2012
.SHORT TERM...VALID FOR TDY AND SUN...
DYNAMIC SHORTWAVE CURRENTLY PUSHING WEST TO EAST THROUGH CENTRAL
MONTANA...WITH DIFFLUENT SIGNATURE OVER OUR SW MTNS...AND AS A
RESULT A HEALTHY SNOW BAND EXISTS NEAR LIVINGSTON...PINE CREEK
AND BIG TIMBER AS WELL AS OVER THE BEARTOOTH ABSAROKAS AS OF 10Z.
FORCING FROM THIS WAVE AND PACIFIC COLD FRONT WILL SLIDE EASTWARD
EARLY THIS MORNING GIVING A BRIEF PERIOD OF SNOW SHOWERS DESPITE
THE DOWNSLOPE WINDS. MORE WIDESPREAD PCPN WILL BE ASSOCIATED WITH
MOIST NW FLOW/TROWAL FROM LATER THIS MORNING INTO THIS EVENING.
THIS CLEARLY SEEN ON SATELLITE IMAGERY DROPPING THRU NORTH CENTRAL
MONTANA...WITH RAP ANALYSIS SHOWING N-NE MID LEVEL FLOW NEAR CUT
BANK AND HAVRE. PACIFIC COLD FRONT HAS PUSHED THROUGH LIVINGSTON
AND JUDITH GAP BUT CANADIAN FRONT IS STILL TO OUR NORTH BETWEEN
CUT BANK AND GREAT FALLS.
FORECAST IS ON TRACK WITH COMBINATION OF SNOW/NW WINDS/BLSN/WIND
CHILLS SET TO IMPACT OUR EASTERN AREAS THIS AFTERNOON AND
EVENING...AND IN FACT THIS IS WHERE STRONGEST WINDS AND DEEPEST
ASCENT WITH TROWAL WILL BE LOCATED. SO NO CHANGES TO ADVISORY IN
THESE AREAS. UPSLOPE FLOW AND GUSTY NW WINDS WILL ALSO FAVOR THE
BIG HORN MOUNTAINS AND WILL ADD THEM TO THE ADVISORY AS WELL...
THOUGH DENDRITIC LAYER STARTS TO BECOME TOO SHALLOW THIS EVENING
PER COLD MID LEVEL TEMPS TO NEAR -20C. OTHER AREA OF INTEREST IS
JUDITH GAP WHICH SHOULD RECEIVE 1-2 INCHES OF SNOW MAINLY THIS
MORNING INTO THE AFTERNOON...ALONG WITH STRONG NW WINDS ONCE COLD
ADVECTION KICKS IN...AND LIKELY SOME BLOWING SNOW AND POOR TRAVEL
CONDITIONS ON HIGHWAY 191.
SATELLITE IMAGERY SHOWS MOISTURE/COLD TOPS EXTENDING NORTHWARD
INTO THE CANADIAN ROCKIES...AND WILL NEED TO MONITOR ITS IMPACTS
AS THE SYSTEM EVOLVES SOUTHWARD. MODELS SHOWING BOUNDARY LAYER
CONVERGENCE SETTING UP LATE TODAY/THIS EVENING ONCE SFC RIDGE
BUILDS INTO OUR EASTERN PLAINS...SO WITH A CONTINUED FEED OF
MOISTURE FROM THE NORTH AND A TEMP PROFILE FAVORABLE FOR DENDRITIC
SNOW GROWTH FEEL THAT OUR WESTERN FOOTHILLS AND PARK COUNTY MAY
RECEIVE A LONGER DURATION AND GREATER SNOWFALL THAN PREVIOUSLY
THOUGHT. FOR NOW HAVE RAISED POPS AND GIVEN LIVINGSTON/PINE
CREEK/RED LODGE AREAS UP TO ABOUT 2 INCHES OF SNOW. WIND WILL BE
MUCH LESS OF AN ISSUE IN THESE AREAS HOWEVER.
AS FOR BILLINGS...SOME MORNING SNOW SHOWERS ALONG PACIFIC FRONT
WILL GIVE WAY TO A PERIOD OF SNOW FROM LATE MORNING THROUGH MOST
OF THE AFTERNOON ONCE WINDS SHIFT NORTH AND WE SEE IMPACTS FROM
TROWAL. SOME DOWNSLOPING OFF THE BULL MTNS COULD BE A FACTOR...BUT
THINK SOMEWHERE NEAR AN INCH OF SNOW IS IN STORE FOR THE CITY...
PERHAPS A BIT MORE IF A CONVERGENT BAND DEVELOPS...ALONG WITH A
GUSTY NORTH WIND. WILL FEEL LIKE WINTER TODAY.
SYSTEM WILL WIND DOWN TONIGHT...WITH A COLD NIGHT IN STORE AS
CANADIAN SURFACE RIDGE BUILDS IN. CURRENT TEMPS IN SOUTHERN
ALBERTA ARE IN THE SINGLE DIGITS/MID TEENS SO WILL PROBABLY SEE
TEMPS PUSH THESE LEVELS BY LATE AFTERNOON PER POST FRONTAL
ADVECTION. IF SKIES CLEAR OUT TONIGHT...WITH LIGHT WINDS AND A
LITTLE FRESH SNOW COVER...LOWS IN THE SINGLE DIGITS OR NEAR ZERO
ARE A GOOD BET. BILLINGS SHOULD SEE ITS COLDEST TEMP YET OF THE
SEASON...SO FAR THE 6 ABOVE ON NOVEMBER 11TH STILL STANDS...AND
BELOW ZERO IS NOT OUT OF THE QUESTION.
SUNDAY WILL BE DRY/CHILLY UNDER THE INFLUENCE OF SFC RIDGE AND
POOR MIXING. KLONDIKE CHINOOK WILL COMMENCE OUT WEST BY
AFTERNOON...AND DOWNSLOPE GRADIENTS REALLY TIGHTEN UP SUNDAY
NIGHT. THIS WILL LEAD TO WIND CONCERNS ALONG THE FOOTHILLS AND
ALSO NEAR BIG TIMBER AND HARLOWTON...WHICH WILL ALSO BE FAVORED
UNDER NW FLOW ALOFT.
JKL
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
THE EXTENDED FORECAST CONTINUES TO REMAIN IN GOOD SHAPE...SO MADE
ONLY MINOR CHANGES...MOSTLY TO INCREASE POPS LATE WEDNESDAY INTO
EARLY THURSDAY AND TO TWEAK WINDS THROUGH THE EXTENDED. THE MAIN
THEME FOR MONDAY THROUGH WEDNESDAY OF NEXT WEEK CONTINUES TO BE
WINDY AND UNSETTLED WEATHER. ON MONDAY...MOIST NORTHWESTERLY FLOW
AND AN EMBEDDED SHORTWAVE WILL BRING SNOW SHOWERS TO MUCH OF THE
FORECAST AREA. PRESSURE FALLS AHEAD OF A SURFACE LOW WILL BRING
GUSTY WESTERLY WINDS ON MONDAY AS WELL. THESE DOWNSLOPE WINDS WILL
KEEP HIGH TEMPS IN THE 30S MONDAY...AND MAY WORK AGAINST SOME OF
THE LIFT ASSOCIATED WITH THE SHORTWAVE AND UPPER LEVEL DYNAMICS.
TUESDAY WILL BRING A BRIEF BREAK IN THE UNSETTLED WEATHER WITH
RIDGING ALOFT. HOWEVER...WINDS WILL INCREASE ON TUESDAY AFTERNOON
ACROSS THE WEST IN RESPONSE A TIGHTENING PRESSURE GRADIENT AND
PRESSURE FALLS NORTH OF THE FORECAST AREA.
BOTH THE ECMWF AND THE GFS ARE CONTINUING TO COME INTO AGREEMENT
REGARDING A PUSH OF COLD AIR INTO THE FORECAST AREA FROM THE
NORTH ON WEDNESDAY AFTERNOON AND OVERNIGHT. MODELS ARE CONSISTENT
WITH DEVELOPING SOME SNOWFALL ALONG THE FRONTOGENESIS ZONE
WEDNESDAY NIGHT AND THURSDAY. TWEAKED TEMPERATURES UPWARDS JUST A
BIT THURSDAY AS MODELS CONTINUE TO TREND TEMPS UP EVER SO
SLIGHTLY.
WEAK RIDGING BUILDS INTO THE REGION FRIDAY...KEEPING MUCH OF THE
REGION DRY...WITH HIGH TEMPS REBOUNDING INTO THE UPPER 20S TO MID
30S. THERE ARE SOME NOTABLE DIFFERENCES IN HOW THE MODELS HANDLE
THE FRIDAY NIGHT TO SATURDAY NIGHT TIMEFRAME...THUS CONFIDENCE IN
THE FORECAST DURING THIS PERIOD IS SOMEWHAT LOW. WOULD LIKE TO SEE
SOME BETTER AGREEMENT BEFORE MAKING SUBSTANTIAL CHANGES TO THE END
OF THE EXTENDED. FOR NOW...KEPT THE FRIDAY NIGHT TO SATURDAY NIGHT
TIMEFRAME MAINLY DRY WITH SEASONAL TEMPERATURES. STC
&&
.AVIATION...
A STORM SYSTEM WILL MOVE THROUGH THE REGION TODAY...ACCOMPANIED BY
A STRONG COLD FRONT. EXPECT CONDITIONS TO DETERIORATE THROUGH THE
MORNING ACROSS MUCH OF THE REGION WITH MVFR/IFR AND LOCALIZED
LIFR/VLIFR CONDITIONS IN SNOW AND LOW CEILINGS LIKELY INTO THIS
EVENING. WINDS WILL SWITCH TO A NW DIRECTION BY MID DAY AT ALL TAF
SITES AND BECOME VERY GUSTY. THE STRONG WINDS WILL INCREASE THE
LIKELIHOOD OF REDUCED VISIBILITY DUE TO BLOWING SNOW. CONDITIONS
WILL IMPROVE TONIGHT AS THE STORM SYSTEM MOVES EAST OF THE REGION
AND WINDS BEGIN TO SUBSIDE. STC
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 028 005/024 020/034 021/037 025/034 015/023 010/032
7/S 30/B 25/S 21/N 14/S 32/S 11/B
LVM 024 000/022 018/031 018/033 025/033 014/026 011/030
6/S 20/N 35/S 31/N 34/S 43/S 11/N
HDN 027 002/025 011/034 018/035 020/039 012/024 008/031
9/S 40/B 35/S 21/B 13/S 32/S 11/B
MLS 025 901/018 011/033 019/034 023/029 010/019 006/027
9/S 60/B 14/S 21/B 13/S 21/E 11/B
4BQ 028 001/020 010/031 017/033 018/034 013/024 006/031
9/S 91/E 15/S 21/B 12/S 32/S 11/B
BHK 025 902/013 008/032 018/032 019/028 010/018 006/027
9/S 80/E 13/S 21/B 12/S 21/E 11/B
SHR 030 003/021 011/032 015/033 017/036 011/024 005/028
8/S 60/B 24/S 31/B 12/S 33/S 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM NOON TODAY TO 6 AM MST
SUNDAY FOR ZONES 31>33-36>38-58.
WINTER WEATHER ADVISORY IN EFFECT UNTIL MIDNIGHT MST TONIGHT
FOR ZONE 63.
WY...WINTER WEATHER ADVISORY IN EFFECT FROM NOON TODAY TO 6 AM MST
SUNDAY FOR ZONE 99.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST SUNDAY FOR
ZONE 98.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
244 PM CST SAT DEC 8 2012
...MUCH COLDER WITH WINDY CONDITIONS LATE TONIGHT AND SUNDAY...
SYNOPSIS... SURFACE LOW PRESSURE RESIDES ACROSS THE CENTRAL HIGH
PLAINS WITH MAIN LOW FORMING NEAR PINE RIDGE SOUTH DAKOTA. LEADING
EDGE OF COLD FRONT JUST PASSED CHADRON. STEEP LAPSE RATES
ATTRIBUTING TO CONVECTIVE SNOW SHOWERS PANHANDLE INTO NORTH
CENTRAL. MUCH OF RADAR ECHOES NOT REACHING GROUND EFFECTIVELY DUE
TO FAIRLY LARGE TEMPERATURES AND DEWPOINT SPREAD. NEVERTHELESS...
THIS HAS BEEN MOISTENING UP THE ATMOSPHERE FOR UPSTREAM
DEVELOPMENT TO TAKE ADVANTAGE OF FOR LATE AFTERNOON INTO THIS
EVENING.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY. MAIN FORECAST CONCERNS OVER
THE NEXT 36 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN OF
COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
SHORTWAVE TROUGH CURRENTLY LOCATED FROM CENTRAL SOUTH DAKOTA INTO
EASTERN MONTANA AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT EAST
ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT THROUGH
THE CWA OVERNIGHT TONIGHT. THE RAP MODEL CONTINUES TO INDICATE THE
SURFACE LOW NEAR AND SOUTH OF I90 TONIGHT WHICH REMAINS FARTHER SOUTH
THAN OTHER SHORT TERM MODELS. AN H3 JET MAX ACROSS NORTHERN
COLORADO AND SOUTHERN NEBRASKA THIS EVENING WILL BE FAVORABLE FOR
ASCENT IN THE LEFT EXIT REGION OF JET ACROSS NORTH CENTRAL
NEBRASKA. AS SUGGESTED BY THE RAP MODEL...REGIONAL GEM AND TO A
LESSER EXTEND THE NAM...BANDED SNOWFALL IS FAVORABLE FROM NEAR
MULLEN THROUGH BASSETT. LOCAL SNOWFALL AMOUNTS NEAR AN INCH
POSSIBLE IN THESE BANDED AREAS. OTHERWISE...LIGHT SNOW ALSO
FORECAST TO DEVELOP AND DROP SOUTH INTO FAR NORTHERN NEBRASKA LATE
TONIGHT INTO SUNDAY MORNING. THIS IS WITHIN SOUTHERN PERIPHERY OF
DEFORMATION ZONE TO BE ACROSS EASTERN SOUTH DAKOTA INTO SOUTH
CENTRAL SOUTH DAKOTA. ANY ASSOCIATED SNOWFALL WOULD REMAIN A HALF
INCH OR LESS. ACROSS THE SOUTHERN HALF OF FORECAST AREA...ANY
LINGERING SNOW OR FLURRIES FROM THIS EVENING SHOULD END SOON
AFTER MIDNIGHT.
STRONG COLD AIR ADVECTION AND LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW
FOR GUSTY CONDITIONS LATER TONIGHT INTO SUNDAY. THE MODELS HAVE
SHOWN A SLIGHT SOUTHWARD TREND IN THE TRACK OF THE SURFACE
LOW...NOW ACROSS FAR SOUTHWEST MINNESOTA. THIS TRACK FAVORS
SLIGHTLY STRONGER SURFACE WINDS THAN PREVIOUSLY ANTICIPATED. WILL
KEEP WIND SPEEDS JUST BELOW ADVISORY CRITERIA...ESPECIALLY SINCE
THE STRONGEST PRESSURE RISES ARE EXPECTED DURING THE EARLY MORNING
HOURS...DIURNALLY UNFAVORABLE FOR ADVISORY CRITERIA WIND.
BUT...WIDESPREAD SUB ZERO WIND CHILLS WILL OCCUR...WITH THE
POTENTIAL OF SOME OF THE LOWEST READINGS APPROACHING MINUS TEN OR
COLDER THROUGH SUNDAY MORNING ACROSS OUR NORTHERN ZONES. HIGHS ON
SUNDAY WILL BE COLD...WITH READINGS TRENDED DOWN TO NEAR 15 AT
VALENTINE TO THE MID 20S FAR SOUTH. WE WILL NEED TO WATCH LOW
TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD ALLOW
READINGS TO PLUMMET...TO POSSIBLY BELOW ZERO. CURRENT FORECAST HAS
LOWS 1 TO 5 ABOVE MOST AREAS...AS WIDESPREAD ACCUMULATING SNOW IS
NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE SLOWLY MONDAY
AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN ADVANCE OF THE
NEXT SHORTWAVE TROUGH. HIGHS TO RANGE IN THE 30S. THEN A WESTERLY
DOWNSLOPE TUESDAY TO WARM READINGS TO THE MID 30S TO LOWER 40S.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. SHORTWAVE RIDGING AND
WAA TAKE HOLD WEDNESDAY THROUGH THURSDAY...WITH TEMPERATURES SLIGHTLY
ABOVE SEASONAL NORMS WEDNESDAY AND NEAR NORMAL THURSDAY. WILL NEED
TO MONITOR IF A BACK DOOR COLD FRONT DROPS INTO NORTH CENTRAL
NEBRASKA THURSDAY. THE ECMWF AND GEM KEEP COLDER AIR TO THE NORTH
INTO SOUTH DAKOTA...WHILE THE GFS BRINGS IT SOUTH INTO NORTHERN
NEBRASKA. THE NEXT SIGNIFICANT TROUGH IS SHOWN TO REACH THE FOUR
CORNERS REGION 12Z FRIDAY AND TRACK INTO NORTHWEST MISSOURI AS A
NEGATIVELY TILTED CLOSED LOW BY 12Z SATURDAY PER THE ECMWF
SOLUTION. THE GFS ALSO INDICATES A NEGATIVELY TILTED
TROUGH...ALTHOUGH AS AN OPEN WAVE FROM WESTERN SOUTH DAKOTA INTO
NORTHERN NEBRASKA. PRECIPITATION CHANCES NOW BROUGHT INTO EASTERN
NEBRASKA FRIDAY NIGHT INCLUDING FAR EASTERN PORTIONS OF NORTH
CENTRAL NEBRASKA. HIGHS FRIDAY FORECAST TO RANGE IN THE 30S AND
MID 30S TO LOW 40S SATURDAY.
&&
.AVIATION...
A SURFACE LOW OVER SOUTHWEST SOUTH DAKOTA WILL PROGRESS EAST ACROSS
SOUTHERN SOUTH DAKOTA THROUGH THE EVENING...WHICH WILL BRING LOWER
CEILINGS AND CHANCES FOR SNOW TO PORTIONS OF NORTHERN
NEBRASKA...INCLUDING KVTN. THERE WILL BE A CHANCE FOR LIGHT SNOW
THIS AFTERNOON IN THESE AREAS...BUT EXPECT VISIBILITIES TO STAY
ABOVE 5SM UNTIL LATER THIS AFTERNOON THROUGH EARLY EVENING WHEN THE
SNOW COULD INTENSIFY AND BRING VISIBILITIES AND CEILINGS DOWN TO
MVFR AND POSSIBLY IFR FOR A TIME. THE EXPECTED PRECIPITATION TYPE
WILL MAINLY BE SNOW...AND THE PRIMARY AREA THAT COULD SEE
ACCUMULATING SNOW IS LIKELY TO STAY NORTH OF A KAIA TO KTIF TO KBVN
LINE.
IN ADDITION...AS THE SURFACE LOW MOVES EAST...A COLD FRONT WILL
MOVE THROUGH THE STATE SWITCHING WINDS TO THE NORTHWEST. COULD SEE
GUSTY WINDS BETWEEN 30 AND 40 KTS...ESPECIALLY ACROSS THE NORTHERN
PARTS OF NEBRASKA LATE TONIGHT INTO SUNDAY MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...ROBERG
AVIATION...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
106 PM CST SAT DEC 8 2012
.UPDATE...
ONE MORE UPDATE TO INCREASE PRECIPITATION CHANCES ACROSS NORTHERN
NEBRASKA THIS AFTERNOON. RADAR ECHOES HAVE BEEN PERSISTENT THROUGH
THE MORNING HOURS ACROSS NORTHERN NEBRASKA WHICH HAS MOISTENED THE
COLUMN...WHICH HAS BEEN CONFIRMED BY LAPS SOUNDINGS IN THE AREA.
ALSO...HAVE HAD CONFIRMATION OF SNOW PELLETS FROM AN OBSERVER NEAR
KAIA WITH AREA WEBCAMS SHOWING SOME LIGHT SNOW ON GRASSY SURFACES
IN PARTS OF SHERIDAN COUNTY. LATEST SURFACE ANALYSIS SHOWS THE
SURFACE LOW HAS MIGRATED INTO SOUTHWEST SOUTH DAKOTA. THE RUC IS
SHOWING GOOD MOISTURE CONTINUING TO ADVECT EASTWARD ON THE SOUTH
SIDE OF THE LOW AS IT MOVES STRAIGHT EAST JUST NORTH OF THE SD/NE
BORDER THIS AFTERNOON. THIS...COMBINED WITH DECENT ISENTROPIC LIFT
IN THE LAYER AND WITH RADAR ECHOES EXTENDING INTO CENTRAL WYOMING
HAD THE CONFIDENCE TO INCREASE PRECIPITATION CHANCES THROUGH THE
AFTERNOON. DEWPOINT SPREADS SHOULD KEEP MOST OF THE PRECIPITATION
AS SNOW...ALTHOUGH SOME RAIN COULD MIX IN AREAS SOUTH OF THE
HIGHWAY 2/91 CORRIDOR.
&&
.PREV DISCUSSION... /ISSUED 1156 AM CST SAT DEC 8 2012/
AVIATION...
A SURFACE LOW WILL PASS ACROSS SOUTHERN SOUTH DAKOTA THROUGH
TONIGHT...WHICH WILL BRING LOWER CEILINGS AND CHANCES FOR SNOW TO
PORTIONS OF NORTHERN NEBRASKA...INCLUDING KVTN. THERE WILL
CONTINUE TO BE A CHANCE FOR LIGHT SNOW THIS AFTERNOON IN THESE
AREAS...BUT EXPECT VISIBILITIES TO STAY ABOVE 5SM UNTIL LATER THIS
AFTERNOON THROUGH EARLY EVENING WHEN THE SNOW COULD INTENSIFY AND
BRING VISIBILITIES AND CEILINGS DOWN TO MVFR AND POSSIBLY IFR FOR A
TIME. THE PRIMARY PRECIPITATION AREA IS LIKELY TO STAY NORTH OF A
KAIA TO KTIF TO KBVN LINE WITH THE EXPECTED PRECIPITATION TYPE
BEING SNOW EVEN IF SURFACE TEMPERATURES RISE ABOVE FREEZING.
IN ADDITION...AS THE SURFACE LOW MOVES EAST...A COLD FRONT WILL
MOVE THROUGH THE STATE SWITCHING WINDS TO THE NORTHWEST. COULD SEE
GUSTY WINDS BETWEEN 30 AND 40 KTS...ESPECIALLY ACROSS THE NORTHERN
PARTS OF NEBRASKA LATE TONIGHT INTO SUNDAY MORNING.
PREV DISCUSSION... /ISSUED 1021 AM CST SAT DEC 8 2012/
UPDATE...
MADE AN ADJUSTMENT TO THE FORECAST FOR TODAY TO ADD IN CHANCE FOR
FLURRIES ACROSS NORTHERN NEBRASKA THIS MORNING AS RADAR ECHOES
HAVE EXPANDED THROUGH THE AREA. THERE REMAINS QUITE A BIT OF DRY
AIR IN THE LOW LEVELS THOUGH WITH CEILINGS STILL AT OR ABOVE 5K
FEET EVEN AS THE COLUMN SATURATES FROM TO DOWN. THEREFORE DON/T
EXPECT ANY ACCUMULATING PRECIPITATION YET THIS MORNING. WATER
VAPOR IMAGERY SHOWS THE MID/UPPER LEVEL PV ANOMALY PUSHING INTO
CENTRAL WYOMING WHICH WILL CONTINUE TO MOVE EAST INTO WESTERN
NEBRASKA THIS AFTERNOON. STILL THINK IT LOOKS GOOD FOR THIS TO
CAUSE THE SURFACE LOW /CURRENTLY OVER THE MONTANA/WYOMING/SOUTH
DAKOTA TRIPLE POINT/ TO STRENGTHEN THIS AFTERNOON AS IT MOVES
EAST. NEAR-TERM AND MESOSCALE MODELS DO INDICATE GOOD WARMING
JUST AHEAD OF THE COLD FRONT THIS AFTERNOON. THINK CLOUD COVER MAY
LIMIT THIS WARMING THOUGH...ESPECIALLY OVER NORTHERN NEBRASKA
WHERE CLOUDS SHOULD BE MORE ABUNDANT. SO DID ADJUST HIGHS DOWNWARD
SLIGHTLY IN THESE AREAS.
WILL CONTINUE TO MONITOR RADAR TRENDS INTO THE AFTERNOON AS THE
UPPER LEVEL SHORTWAVE MOVES CLOSER AND MAY NEED TO ADJUST
PRECIPITATION CHANCES UPWARD FOR THE AFTERNOON HOURS ACROSS THE
NORTH.
PREV DISCUSSION... /ISSUED 624 AM CST SAT DEC 8 2012/
UPDATE...
DISCUSSION...
A NEW FORECAST IS IN PLACE...MAINLY AFFECTING NORTHERN NEBRASKA.
THE RAP MODEL...WHICH HAS BEEN PERFORMING WELL WITH THIS
SYSTEM...SUGGESTS THE SFC LOW WILL TRACK ALONG THE SD-NEB BORDER
LATE THIS AFTN AND THIS EVENING. THIS IS ABOUT 100 MILES OR SO
FARTHER SOUTH THAN THE ENSEMBLE FCST.
IT ALSO CARRIES THE PV15 CENTER FARTHER SOUTH. ENHANCED
ADVECTIONS OF TEMPERATURE AND MOISTURE SHOW A MARKED STRENGTHENING
OF 700 MB FRONTOGENESIS NEAR THE SFC LOW LATE THIS AFTN AND THIS
EVENING. THUS...AS INDICATED BY THE MODEL...GREATER POPS AND QPF
ARE WARRANTED FOR NRN NEB WITH A RAIN CHANGEOVER TO SNOW WITH THE
PASSAGE OF A PACIFIC FRONT EARLY THIS EVENING FOLLOWED BY ARCTIC
AIR MOVING IN AROUND 06Z OR LATER.
POPS ARE HELD AT 40 PERCENT GIVEN THE UNCERTAINTIES OF THIS
RAPID CHANGE IN THE MODEL AND THE MIXED PCPN WOULD PERHAPS YEILD
AN INCH OR TWO OF SNOW. THE REST OF THE FCST IS ON TRACK.
PREV DISCUSSION... /ISSUED 400 AM CST SAT DEC 8 2012/
SYNOPSIS...
EVENING HAND ANALYSIS OF THE H5 LEVEL REVEALS A BROAD LONGWAVE
TROUGH ENCOMPASSING MUCH OF THE CONTIGUOUS 48...WITH RIDGING OFF
BOTH THE WESTERN AND EASTERN COASTS. SEVERAL SHORTWAVES ARE SEEN
MOVING THROUGH THE BROAD TROUGH...WITH ONE NOW EAST OF THE UPPER
MISSISSIPPI VALLEY...AND THE NEXT APPROACHING THE NORTHERN/CENTRAL
HIGH PLAINS FROM THE WEST. AT THE SURFACE...AN AREA OF LOW PRESSURE
IS STARTING TO DEEPEN OVER CENTRAL MONTANA WITH HIGH PRESSURE
LOCATED OVER THE MISSOURI VALLEY. WHILE WINDS ARE FAIRLY LIGHT AND
VARIABLE AT THIS HOUR ACROSS THE CWA...FURTHER WEST ACROSS THE HIGH
PLAINS...SURFACE WINDS ARE STARTING TO TAKE ON A MORE SOUTHERLY
COMPONENT. TEMPERATURES EARLY THIS AM RANGE FROM A CHILLY 13
DEGREES FAHRENHEIT AT KLBF...TO AS WARM AS 30 AT KONL WHERE STRATUS
IS LOCKED IN PLACE.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH 12Z TUESDAY. MAIN FORECAST CONCERNS
OVER THE NEXT 72 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN
OF COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
WESTERN SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT
EAST ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT
THROUGH THE CWA LATE TODAY/OVERNIGHT TONIGHT. THE STRONGEST OMEGA
CONTINUES TO BE SUGGESTED WELL NORTH OF THE CWA...IN CLOSE VICINITY
TO THE TROUGH AXIS...HOWEVER MOST NEAR TERM MODEL SOLUTIONS GENERATE
LIGHT QPF AHEAD OF A MID-LEVEL FGEN BAND WHERE WEAK THERMAL
ADVECTION AND A BRIEF PERIOD OF UPGLIDE MAY BE SUFFICIENT ENOUGH TO
SQUEEZE OUT A HUNDREDTH OR TWO OF AN INCH OF PRECIPITATION THIS
AFTERNOON. THE BETTER DYNAMICS FOR PRECIPITATION PRODUCTION ARRIVES
WITH THE MID LEVEL FRONTOGENETIC BAND LATE THIS
AFTERNOON/EVENING...HOWEVER FORECAST PROXIMITY SOUNDINGS FROM ACROSS
THE CWA SUGGEST THE LOWER LEVELS OF THE ATMOSPHERE WILL QUICKLY DRY
OUT AS STRONG COLD/DRY AIR ADVECTION SPILLS IN BEHIND THE PASSING
BOUNDARY. THE ENSEMBLES...AND DETERMINISTIC SOLUTIONS ALL HAVE
CONVERGED THAT AT MOST LESS THAN .05 OF AN INCH OF QPF WOULD BE
GENERATED...SO ONLY LOOKING FOR A DUSTING TO POSSIBLY A HALF OF AN
INCH ACROSS THE SANDHILLS AND POINTS SOUTHEAST WHERE ADDITIONAL LIFT
MAY BE GENERATED WITHIN THE VICINITY OF THE RIGHT ENTRANCE OF A
PASSING UPPER JET. ACROSS NORTHERN NEBRASKA...THE NEAR TERM
CONSENSUS IS SUGGESTING A PERIOD OF POSSIBLE WRAP AROUND AS THE
SURFACE LOW ADVANCES INTO WEST CENTRAL MINNESOTA...THE POTENTIAL OF
SLIGHTLY HEAVIER SNOW ACCUMULATION EXIST...BUT LESS THAN AN INCH
WOULD BE EXPECT AT BEST WITH THE SNOW FALLING OVERNIGHT TONIGHT.
THE SHORTWAVE QUICKLY ADVANCES EAST OVERNIGHT BRINGING AN END TO
PRECIPITATION CHANCES FOR THE FORESEEABLE FUTURE AS AN OVERALL LACK
OF KINEMATIC FORCING IS SUGGESTED IN THE SHORT AND LONG TERM
SOLUTIONS.
STRONG COLD AIR ADVECTION AND MODEST LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW FOR
GUSTY CONDITIONS EARLY ON SUNDAY. THE MODELS HAVE SHOWN A SLIGHT
NORTHWARD TREND IN THE TRACK OF THE SURFACE LOW...NOW ACROSS WEST
CENTRAL MINNESOTA. THIS TRACK FAVORS SLIGHTLY WEAKER SURFACE WINDS
THAN PREVIOUSLY ANTICIPATED. SO WILL KEEP WIND SPEEDS BELOW
ADVISORY CRITERIA...ESPECIALLY SINCE THE STRONGEST PRESSURE RISES
ARE EXPECTED DURING THE EARLY MORNING HOURS...DIURNALLY UNFAVORABLE
FOR ADVISORY CRITERIA WIND. BUT...WIDESPREAD SUB ZERO WIND CHILLS
WILL BE POSSIBLE...WITH THE POTENTIAL OF SOME OF THE LOWEST READINGS
APPROACHING MINUS TEN OR COLDER AS H9 TEMPERATURES FALL AS COLD AS
MINUS 12C ACROSS OUR NORTHERN ZONES. HIGHS ON SUNDAY WILL BE
CHILLY...WITH READINGS RANGING FROM THE UPPER TEENS ACROSS THE
NORTH...TO THE UPPER 20S ACROSS THE FAR SOUTHWEST. WE WILL NEED TO
WATCH LOW TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD
ALLOW READINGS TO PLUMMET...TO POSSIBLY BELOW 0F. WILL KEEP
FORECAST VALUES IN THE SINGLE DIGITS FOR NOW...AS WIDESPREAD
ACCUMULATING SNOW IS NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE
SLOWLY MONDAY AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN
ADVANCE OF THE NEXT SHORTWAVE TROUGH.
LONG TERM...12Z TUESDAY AND BEYOND. THE NEXT WAVE PASSES THROUGH
EARLY TUESDAY...HOWEVER MOISTURE REMAINS IN QUESTION...AND KINEMATIC
FORCING REMAINS SOMEWHAT WEAK AND TO THE SOUTH...THUS CONFIDENCE IS
TOO LOW TO INTRODUCE POPS INTO THE FORECAST. OTHERWISE SHORTWAVE
RIDGING AND WAA TAKE HOLD THROUGH THE END OF NEXT WEEK...WITH
TEMPERATURES REMAINING NEAR TO SLIGHTLY ABOVE SEASONAL NORMS. THE
NEXT SIGNIFICANT TROUGH IS SHOWN TO ARRIVE ACROSS THE WEST LATE NEXT
WEEK...BUT WITH THIS EVENINGS MODEL RUNS...PRECIPITATION CHANCES
LOOK TO REMAIN WELL TO THE SOUTH AND WEST OF THE CWA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION/UPDATE...BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1156 AM CST SAT DEC 8 2012
.AVIATION...
A SURFACE LOW WILL PASS ACROSS SOUTHERN SOUTH DAKOTA THROUGH
TONIGHT...WHICH WILL BRING LOWER CEILINGS AND CHANCES FOR SNOW TO
PORTIONS OF NORTHERN NEBRASKA...INCLUDING KVTN. THERE WILL
CONTINUE TO BE A CHANCE FOR LIGHT SNOW THIS AFTERNOON IN THESE
AREAS...BUT EXPECT VISIBILITIES TO STAY ABOVE 5SM UNTIL LATER THIS
AFTERNOON THROUGH EARLY EVENING WHEN THE SNOW COULD INTENSIFY AND
BRING VISIBILITIES AND CEILINGS DOWN TO MVFR AND POSSIBLY IFR FOR A
TIME. THE PRIMARY PRECIPITATION AREA IS LIKELY TO STAY NORTH OF A
KAIA TO KTIF TO KBVN LINE WITH THE EXPECTED PRECIPITATION TYPE
BEING SNOW EVEN IF SURFACE TEMPERATURES RISE ABOVE FREEZING.
IN ADDITION...AS THE SURFACE LOW MOVES EAST...A COLD FRONT WILL
MOVE THROUGH THE STATE SWITCHING WINDS TO THE NORTHWEST. COULD SEE
GUSTY WINDS BETWEEN 30 AND 40 KTS...ESPECIALLY ACROSS THE NORTHERN
PARTS OF NEBRASKA LATE TONIGHT INTO SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1021 AM CST SAT DEC 8 2012/
UPDATE...
MADE AN ADJUSTMENT TO THE FORECAST FOR TODAY TO ADD IN CHANCE FOR
FLURRIES ACROSS NORTHERN NEBRASKA THIS MORNING AS RADAR ECHOES
HAVE EXPANDED THROUGH THE AREA. THERE REMAINS QUITE A BIT OF DRY
AIR IN THE LOW LEVELS THOUGH WITH CEILINGS STILL AT OR ABOVE 5K
FEET EVEN AS THE COLUMN SATURATES FROM TO DOWN. THEREFORE DON/T
EXPECT ANY ACCUMULATING PRECIPITATION YET THIS MORNING. WATER
VAPOR IMAGERY SHOWS THE MID/UPPER LEVEL PV ANOMALY PUSHING INTO
CENTRAL WYOMING WHICH WILL CONTINUE TO MOVE EAST INTO WESTERN
NEBRASKA THIS AFTERNOON. STILL THINK IT LOOKS GOOD FOR THIS TO
CAUSE THE SURFACE LOW /CURRENTLY OVER THE MONTANA/WYOMING/SOUTH
DAKOTA TRIPLE POINT/ TO STRENGTHEN THIS AFTERNOON AS IT MOVES
EAST. NEAR-TERM AND MESOSCALE MODELS DO INDICATE GOOD WARMING
JUST AHEAD OF THE COLD FRONT THIS AFTERNOON. THINK CLOUD COVER MAY
LIMIT THIS WARMING THOUGH...ESPECIALLY OVER NORTHERN NEBRASKA
WHERE CLOUDS SHOULD BE MORE ABUNDANT. SO DID ADJUST HIGHS DOWNWARD
SLIGHTLY IN THESE AREAS.
WILL CONTINUE TO MONITOR RADAR TRENDS INTO THE AFTERNOON AS THE
UPPER LEVEL SHORTWAVE MOVES CLOSER AND MAY NEED TO ADJUST
PRECIPITATION CHANCES UPWARD FOR THE AFTERNOON HOURS ACROSS THE
NORTH.
PREV DISCUSSION... /ISSUED 624 AM CST SAT DEC 8 2012/
UPDATE...
DISCUSSION...
A NEW FORECAST IS IN PLACE...MAINLY AFFECTING NORTHERN NEBRASKA.
THE RAP MODEL...WHICH HAS BEEN PERFORMING WELL WITH THIS
SYSTEM...SUGGESTS THE SFC LOW WILL TRACK ALONG THE SD-NEB BORDER
LATE THIS AFTN AND THIS EVENING. THIS IS ABOUT 100 MILES OR SO
FARTHER SOUTH THAN THE ENSEMBLE FCST.
IT ALSO CARRIES THE PV15 CENTER FARTHER SOUTH. ENHANCED
ADVECTIONS OF TEMPERATURE AND MOISTURE SHOW A MARKED STRENGTHENING
OF 700 MB FRONTOGENESIS NEAR THE SFC LOW LATE THIS AFTN AND THIS
EVENING. THUS...AS INDICATED BY THE MODEL...GREATER POPS AND QPF
ARE WARRANTED FOR NRN NEB WITH A RAIN CHANGEOVER TO SNOW WITH THE
PASSAGE OF A PACIFIC FRONT EARLY THIS EVENING FOLLOWED BY ARCTIC
AIR MOVING IN AROUND 06Z OR LATER.
POPS ARE HELD AT 40 PERCENT GIVEN THE UNCERTAINTIES OF THIS
RAPID CHANGE IN THE MODEL AND THE MIXED PCPN WOULD PERHAPS YEILD
AN INCH OR TWO OF SNOW. THE REST OF THE FCST IS ON TRACK.
PREV DISCUSSION... /ISSUED 400 AM CST SAT DEC 8 2012/
SYNOPSIS...
EVENING HAND ANALYSIS OF THE H5 LEVEL REVEALS A BROAD LONGWAVE
TROUGH ENCOMPASSING MUCH OF THE CONTIGUOUS 48...WITH RIDGING OFF
BOTH THE WESTERN AND EASTERN COASTS. SEVERAL SHORTWAVES ARE SEEN
MOVING THROUGH THE BROAD TROUGH...WITH ONE NOW EAST OF THE UPPER
MISSISSIPPI VALLEY...AND THE NEXT APPROACHING THE NORTHERN/CENTRAL
HIGH PLAINS FROM THE WEST. AT THE SURFACE...AN AREA OF LOW PRESSURE
IS STARTING TO DEEPEN OVER CENTRAL MONTANA WITH HIGH PRESSURE
LOCATED OVER THE MISSOURI VALLEY. WHILE WINDS ARE FAIRLY LIGHT AND
VARIABLE AT THIS HOUR ACROSS THE CWA...FURTHER WEST ACROSS THE HIGH
PLAINS...SURFACE WINDS ARE STARTING TO TAKE ON A MORE SOUTHERLY
COMPONENT. TEMPERATURES EARLY THIS AM RANGE FROM A CHILLY 13
DEGREES FAHRENHEIT AT KLBF...TO AS WARM AS 30 AT KONL WHERE STRATUS
IS LOCKED IN PLACE.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH 12Z TUESDAY. MAIN FORECAST CONCERNS
OVER THE NEXT 72 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN
OF COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
WESTERN SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT
EAST ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT
THROUGH THE CWA LATE TODAY/OVERNIGHT TONIGHT. THE STRONGEST OMEGA
CONTINUES TO BE SUGGESTED WELL NORTH OF THE CWA...IN CLOSE VICINITY
TO THE TROUGH AXIS...HOWEVER MOST NEAR TERM MODEL SOLUTIONS GENERATE
LIGHT QPF AHEAD OF A MID-LEVEL FGEN BAND WHERE WEAK THERMAL
ADVECTION AND A BRIEF PERIOD OF UPGLIDE MAY BE SUFFICIENT ENOUGH TO
SQUEEZE OUT A HUNDREDTH OR TWO OF AN INCH OF PRECIPITATION THIS
AFTERNOON. THE BETTER DYNAMICS FOR PRECIPITATION PRODUCTION ARRIVES
WITH THE MID LEVEL FRONTOGENETIC BAND LATE THIS
AFTERNOON/EVENING...HOWEVER FORECAST PROXIMITY SOUNDINGS FROM ACROSS
THE CWA SUGGEST THE LOWER LEVELS OF THE ATMOSPHERE WILL QUICKLY DRY
OUT AS STRONG COLD/DRY AIR ADVECTION SPILLS IN BEHIND THE PASSING
BOUNDARY. THE ENSEMBLES...AND DETERMINISTIC SOLUTIONS ALL HAVE
CONVERGED THAT AT MOST LESS THAN .05 OF AN INCH OF QPF WOULD BE
GENERATED...SO ONLY LOOKING FOR A DUSTING TO POSSIBLY A HALF OF AN
INCH ACROSS THE SANDHILLS AND POINTS SOUTHEAST WHERE ADDITIONAL LIFT
MAY BE GENERATED WITHIN THE VICINITY OF THE RIGHT ENTRANCE OF A
PASSING UPPER JET. ACROSS NORTHERN NEBRASKA...THE NEAR TERM
CONSENSUS IS SUGGESTING A PERIOD OF POSSIBLE WRAP AROUND AS THE
SURFACE LOW ADVANCES INTO WEST CENTRAL MINNESOTA...THE POTENTIAL OF
SLIGHTLY HEAVIER SNOW ACCUMULATION EXIST...BUT LESS THAN AN INCH
WOULD BE EXPECT AT BEST WITH THE SNOW FALLING OVERNIGHT TONIGHT.
THE SHORTWAVE QUICKLY ADVANCES EAST OVERNIGHT BRINGING AN END TO
PRECIPITATION CHANCES FOR THE FORESEEABLE FUTURE AS AN OVERALL LACK
OF KINEMATIC FORCING IS SUGGESTED IN THE SHORT AND LONG TERM
SOLUTIONS.
STRONG COLD AIR ADVECTION AND MODEST LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW FOR
GUSTY CONDITIONS EARLY ON SUNDAY. THE MODELS HAVE SHOWN A SLIGHT
NORTHWARD TREND IN THE TRACK OF THE SURFACE LOW...NOW ACROSS WEST
CENTRAL MINNESOTA. THIS TRACK FAVORS SLIGHTLY WEAKER SURFACE WINDS
THAN PREVIOUSLY ANTICIPATED. SO WILL KEEP WIND SPEEDS BELOW
ADVISORY CRITERIA...ESPECIALLY SINCE THE STRONGEST PRESSURE RISES
ARE EXPECTED DURING THE EARLY MORNING HOURS...DIURNALLY UNFAVORABLE
FOR ADVISORY CRITERIA WIND. BUT...WIDESPREAD SUB ZERO WIND CHILLS
WILL BE POSSIBLE...WITH THE POTENTIAL OF SOME OF THE LOWEST READINGS
APPROACHING MINUS TEN OR COLDER AS H9 TEMPERATURES FALL AS COLD AS
MINUS 12C ACROSS OUR NORTHERN ZONES. HIGHS ON SUNDAY WILL BE
CHILLY...WITH READINGS RANGING FROM THE UPPER TEENS ACROSS THE
NORTH...TO THE UPPER 20S ACROSS THE FAR SOUTHWEST. WE WILL NEED TO
WATCH LOW TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD
ALLOW READINGS TO PLUMMET...TO POSSIBLY BELOW 0F. WILL KEEP
FORECAST VALUES IN THE SINGLE DIGITS FOR NOW...AS WIDESPREAD
ACCUMULATING SNOW IS NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE
SLOWLY MONDAY AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN
ADVANCE OF THE NEXT SHORTWAVE TROUGH.
LONG TERM...12Z TUESDAY AND BEYOND. THE NEXT WAVE PASSES THROUGH
EARLY TUESDAY...HOWEVER MOISTURE REMAINS IN QUESTION...AND KINEMATIC
FORCING REMAINS SOMEWHAT WEAK AND TO THE SOUTH...THUS CONFIDENCE IS
TOO LOW TO INTRODUCE POPS INTO THE FORECAST. OTHERWISE SHORTWAVE
RIDGING AND WAA TAKE HOLD THROUGH THE END OF NEXT WEEK...WITH
TEMPERATURES REMAINING NEAR TO SLIGHTLY ABOVE SEASONAL NORMS. THE
NEXT SIGNIFICANT TROUGH IS SHOWN TO ARRIVE ACROSS THE WEST LATE NEXT
WEEK...BUT WITH THIS EVENINGS MODEL RUNS...PRECIPITATION CHANCES
LOOK TO REMAIN WELL TO THE SOUTH AND WEST OF THE CWA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
UPDATES...CDC/BROOKS
AVIATION...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1021 AM CST SAT DEC 8 2012
.UPDATE...
MADE AN ADJUSTMENT TO THE FORECAST FOR TODAY TO ADD IN CHANCE FOR
FLURRIES ACROSS NORTHERN NEBRASKA THIS MORNING AS RADAR ECHOES
HAVE EXPANDED THROUGH THE AREA. THERE REMAINS QUITE A BIT OF DRY
AIR IN THE LOW LEVELS THOUGH WITH CEILINGS STILL AT OR ABOVE 5K
FEET EVEN AS THE COLUMN SATURATES FROM TO DOWN. THEREFORE DON/T
EXPECT ANY ACCUMULATING PRECIPITATION YET THIS MORNING. WATER
VAPOR IMAGERY SHOWS THE MID/UPPER LEVEL PV ANOMALY PUSHING INTO
CENTRAL WYOMING WHICH WILL CONTINUE TO MOVE EAST INTO WESTERN
NEBRASKA THIS AFTERNOON. STILL THINK IT LOOKS GOOD FOR THIS TO
CAUSE THE SURFACE LOW /CURRENTLY OVER THE MONTANA/WYOMING/SOUTH
DAKOTA TRIPLE POINT/ TO STRENGTHEN THIS AFTERNOON AS IT MOVES
EAST. NEAR-TERM AND MESOSCALE MODELS DO INDICATE GOOD WARMING
JUST AHEAD OF THE COLD FRONT THIS AFTERNOON. THINK CLOUD COVER MAY
LIMIT THIS WARMING THOUGH...ESPECIALLY OVER NORTHERN NEBRASKA
WHERE CLOUDS SHOULD BE MORE ABUNDANT. SO DID ADJUST HIGHS DOWNWARD
SLIGHTLY IN THESE AREAS.
WILL CONTINUE TO MONITOR RADAR TRENDS INTO THE AFTERNOON AS THE
UPPER LEVEL SHORTWAVE MOVES CLOSER AND MAY NEED TO ADJUST
PRECIPITATION CHANCES UPWARD FOR THE AFTERNOON HOURS ACROSS THE
NORTH.
&&
.PREV DISCUSSION... /ISSUED 624 AM CST SAT DEC 8 2012/
UPDATE...
DISCUSSION...
A NEW FORECAST IS IN PLACE...MAINLY AFFECTING NORTHERN NEBRASKA.
THE RAP MODEL...WHICH HAS BEEN PERFORMING WELL WITH THIS
SYSTEM...SUGGESTS THE SFC LOW WILL TRACK ALONG THE SD-NEB BORDER
LATE THIS AFTN AND THIS EVENING. THIS IS ABOUT 100 MILES OR SO
FARTHER SOUTH THAN THE ENSEMBLE FCST.
IT ALSO CARRIES THE PV15 CENTER FARTHER SOUTH. ENHANCED
ADVECTIONS OF TEMPERATURE AND MOISTURE SHOW A MARKED STRENGTHENING
OF 700 MB FRONTOGENESIS NEAR THE SFC LOW LATE THIS AFTN AND THIS
EVENING. THUS...AS INDICATED BY THE MODEL...GREATER POPS AND QPF
ARE WARRANTED FOR NRN NEB WITH A RAIN CHANGEOVER TO SNOW WITH THE
PASSAGE OF A PACIFIC FRONT EARLY THIS EVENING FOLLOWED BY ARCTIC
AIR MOVING IN AROUND 06Z OR LATER.
POPS ARE HELD AT 40 PERCENT GIVEN THE UNCERTAINTIES OF THIS
RAPID CHANGE IN THE MODEL AND THE MIXED PCPN WOULD PERHAPS YEILD
AN INCH OR TWO OF SNOW. THE REST OF THE FCST IS ON TRACK.
PREV DISCUSSION... /ISSUED 533 AM CST SAT DEC 8 2012/
UPDATE...
AVIATION...
MVFR CIGS ARE EXPECTED IN SOME AREAS TODAY AND TONIGHT.
THE RUC MODEL...WHICH HAS BEEN PERFORMING WELL...SHOWS THE
MVFR/LOCAL IFR CIGS ACROSS NCNTL NEB LIFTING NORTH THIS AFTERNOON
WITH MVFR CIGS FILLING IN AGAIN TONIGHT AS AN ARCTIC FRONT MOVES
INTO WRN/NCNTL NEB.
MEANWHILE A WARM FRONT DEVELOPING ACROSS SRN NEB THIS MORNING WILL
LIFT NORTH DURING THE DAY TODAY PRODUCING ISOLATED RAIN AND SNOW
SHOWERS AND LOCAL MVFR CIGS. ADDITIONAL SCATTERED SNOW SHOWERS/MVFR
CIGS ARE EXPECTED TONIGHT ALONG AND BEHIND THE ARCTIC FRONT.
WINDS ALONG AND BEHIND THE FRONT WILL INCREASE TO 32025G35KT TONIGHT.
PREV DISCUSSION... /ISSUED 400 AM CST SAT DEC 8 2012/
SYNOPSIS...
EVENING HAND ANALYSIS OF THE H5 LEVEL REVEALS A BROAD LONGWAVE
TROUGH ENCOMPASSING MUCH OF THE CONTIGUOUS 48...WITH RIDGING OFF
BOTH THE WESTERN AND EASTERN COASTS. SEVERAL SHORTWAVES ARE SEEN
MOVING THROUGH THE BROAD TROUGH...WITH ONE NOW EAST OF THE UPPER
MISSISSIPPI VALLEY...AND THE NEXT APPROACHING THE NORTHERN/CENTRAL
HIGH PLAINS FROM THE WEST. AT THE SURFACE...AN AREA OF LOW PRESSURE
IS STARTING TO DEEPEN OVER CENTRAL MONTANA WITH HIGH PRESSURE
LOCATED OVER THE MISSOURI VALLEY. WHILE WINDS ARE FAIRLY LIGHT AND
VARIABLE AT THIS HOUR ACROSS THE CWA...FURTHER WEST ACROSS THE HIGH
PLAINS...SURFACE WINDS ARE STARTING TO TAKE ON A MORE SOUTHERLY
COMPONENT. TEMPERATURES EARLY THIS AM RANGE FROM A CHILLY 13
DEGREES FAHRENHEIT AT KLBF...TO AS WARM AS 30 AT KONL WHERE STRATUS
IS LOCKED IN PLACE.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH 12Z TUESDAY. MAIN FORECAST CONCERNS
OVER THE NEXT 72 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN
OF COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
WESTERN SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT
EAST ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT
THROUGH THE CWA LATE TODAY/OVERNIGHT TONIGHT. THE STRONGEST OMEGA
CONTINUES TO BE SUGGESTED WELL NORTH OF THE CWA...IN CLOSE VICINITY
TO THE TROUGH AXIS...HOWEVER MOST NEAR TERM MODEL SOLUTIONS GENERATE
LIGHT QPF AHEAD OF A MID-LEVEL FGEN BAND WHERE WEAK THERMAL
ADVECTION AND A BRIEF PERIOD OF UPGLIDE MAY BE SUFFICIENT ENOUGH TO
SQUEEZE OUT A HUNDREDTH OR TWO OF AN INCH OF PRECIPITATION THIS
AFTERNOON. THE BETTER DYNAMICS FOR PRECIPITATION PRODUCTION ARRIVES
WITH THE MID LEVEL FRONTOGENETIC BAND LATE THIS
AFTERNOON/EVENING...HOWEVER FORECAST PROXIMITY SOUNDINGS FROM ACROSS
THE CWA SUGGEST THE LOWER LEVELS OF THE ATMOSPHERE WILL QUICKLY DRY
OUT AS STRONG COLD/DRY AIR ADVECTION SPILLS IN BEHIND THE PASSING
BOUNDARY. THE ENSEMBLES...AND DETERMINISTIC SOLUTIONS ALL HAVE
CONVERGED THAT AT MOST LESS THAN .05 OF AN INCH OF QPF WOULD BE
GENERATED...SO ONLY LOOKING FOR A DUSTING TO POSSIBLY A HALF OF AN
INCH ACROSS THE SANDHILLS AND POINTS SOUTHEAST WHERE ADDITIONAL LIFT
MAY BE GENERATED WITHIN THE VICINITY OF THE RIGHT ENTRANCE OF A
PASSING UPPER JET. ACROSS NORTHERN NEBRASKA...THE NEAR TERM
CONSENSUS IS SUGGESTING A PERIOD OF POSSIBLE WRAP AROUND AS THE
SURFACE LOW ADVANCES INTO WEST CENTRAL MINNESOTA...THE POTENTIAL OF
SLIGHTLY HEAVIER SNOW ACCUMULATION EXIST...BUT LESS THAN AN INCH
WOULD BE EXPECT AT BEST WITH THE SNOW FALLING OVERNIGHT TONIGHT.
THE SHORTWAVE QUICKLY ADVANCES EAST OVERNIGHT BRINGING AN END TO
PRECIPITATION CHANCES FOR THE FORESEEABLE FUTURE AS AN OVERALL LACK
OF KINEMATIC FORCING IS SUGGESTED IN THE SHORT AND LONG TERM
SOLUTIONS.
STRONG COLD AIR ADVECTION AND MODEST LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW FOR
GUSTY CONDITIONS EARLY ON SUNDAY. THE MODELS HAVE SHOWN A SLIGHT
NORTHWARD TREND IN THE TRACK OF THE SURFACE LOW...NOW ACROSS WEST
CENTRAL MINNESOTA. THIS TRACK FAVORS SLIGHTLY WEAKER SURFACE WINDS
THAN PREVIOUSLY ANTICIPATED. SO WILL KEEP WIND SPEEDS BELOW
ADVISORY CRITERIA...ESPECIALLY SINCE THE STRONGEST PRESSURE RISES
ARE EXPECTED DURING THE EARLY MORNING HOURS...DIURNALLY UNFAVORABLE
FOR ADVISORY CRITERIA WIND. BUT...WIDESPREAD SUB ZERO WIND CHILLS
WILL BE POSSIBLE...WITH THE POTENTIAL OF SOME OF THE LOWEST READINGS
APPROACHING MINUS TEN OR COLDER AS H9 TEMPERATURES FALL AS COLD AS
MINUS 12C ACROSS OUR NORTHERN ZONES. HIGHS ON SUNDAY WILL BE
CHILLY...WITH READINGS RANGING FROM THE UPPER TEENS ACROSS THE
NORTH...TO THE UPPER 20S ACROSS THE FAR SOUTHWEST. WE WILL NEED TO
WATCH LOW TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD
ALLOW READINGS TO PLUMMET...TO POSSIBLY BELOW 0F. WILL KEEP
FORECAST VALUES IN THE SINGLE DIGITS FOR NOW...AS WIDESPREAD
ACCUMULATING SNOW IS NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE
SLOWLY MONDAY AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN
ADVANCE OF THE NEXT SHORTWAVE TROUGH.
LONG TERM...12Z TUESDAY AND BEYOND. THE NEXT WAVE PASSES THROUGH
EARLY TUESDAY...HOWEVER MOISTURE REMAINS IN QUESTION...AND KINEMATIC
FORCING REMAINS SOMEWHAT WEAK AND TO THE SOUTH...THUS CONFIDENCE IS
TOO LOW TO INTRODUCE POPS INTO THE FORECAST. OTHERWISE SHORTWAVE
RIDGING AND WAA TAKE HOLD THROUGH THE END OF NEXT WEEK...WITH
TEMPERATURES REMAINING NEAR TO SLIGHTLY ABOVE SEASONAL NORMS. THE
NEXT SIGNIFICANT TROUGH IS SHOWN TO ARRIVE ACROSS THE WEST LATE NEXT
WEEK...BUT WITH THIS EVENINGS MODEL RUNS...PRECIPITATION CHANCES
LOOK TO REMAIN WELL TO THE SOUTH AND WEST OF THE CWA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION/UPDATE1...CDC
UPDATE2...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
624 AM CST SAT DEC 8 2012
.UPDATE...
.DISCUSSION...
A NEW FORECAST IS IN PLACE...MAINLY AFFECTING NORTHERN NEBRASKA.
THE RAP MODEL...WHICH HAS BEEN PERFORMING WELL WITH THIS
SYSTEM...SUGGESTS THE SFC LOW WILL TRACK ALONG THE SD-NEB BORDER
LATE THIS AFTN AND THIS EVENING. THIS IS ABOUT 100 MILES OR SO
FARTHER SOUTH THAN THE ENSEMBLE FCST.
IT ALSO CARRIES THE PV15 CENTER FARTHER SOUTH. ENHANCED
ADVECTIONS OF TEMPERATURE AND MOISTURE SHOW A MARKED STRENGTHENING
OF 700 MB FRONTOGENESIS NEAR THE SFC LOW LATE THIS AFTN AND THIS
EVENING. THUS...AS INDICATED BY THE MODEL...GREATER POPS AND QPF
ARE WARRANTED FOR NRN NEB WITH A RAIN CHANGEOVER TO SNOW WITH THE
PASSAGE OF A PACIFIC FRONT EARLY THIS EVENING FOLLOWED BY ARCTIC
AIR MOVING IN AROUND 06Z OR LATER.
POPS ARE HELD AT 40 PERCENT GIVEN THE UNCERTAINTIES OF THIS
RAPID CHANGE IN THE MODEL AND THE MIXED PCPN WOULD PERHAPS YEILD
AN INCH OR TWO OF SNOW. THE REST OF THE FCST IS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 533 AM CST SAT DEC 8 2012/
UPDATE...
AVIATION...
MVFR CIGS ARE EXPECTED IN SOME AREAS TODAY AND TONIGHT.
THE RUC MODEL...WHICH HAS BEEN PERFORMING WELL...SHOWS THE
MVFR/LOCAL IFR CIGS ACROSS NCNTL NEB LIFTING NORTH THIS AFTERNOON
WITH MVFR CIGS FILLING IN AGAIN TONIGHT AS AN ARCTIC FRONT MOVES
INTO WRN/NCNTL NEB.
MEANWHILE A WARM FRONT DEVELOPING ACROSS SRN NEB THIS MORNING WILL
LIFT NORTH DURING THE DAY TODAY PRODUCING ISOLATED RAIN AND SNOW
SHOWERS AND LOCAL MVFR CIGS. ADDITIONAL SCATTERED SNOW SHOWERS/MVFR
CIGS ARE EXPECTED TONIGHT ALONG AND BEHIND THE ARCTIC FRONT.
WINDS ALONG AND BEHIND THE FRONT WILL INCREASE TO 32025G35KT TONIGHT.
PREV DISCUSSION... /ISSUED 400 AM CST SAT DEC 8 2012/
SYNOPSIS...
EVENING HAND ANALYSIS OF THE H5 LEVEL REVEALS A BROAD LONGWAVE
TROUGH ENCOMPASSING MUCH OF THE CONTIGUOUS 48...WITH RIDGING OFF
BOTH THE WESTERN AND EASTERN COASTS. SEVERAL SHORTWAVES ARE SEEN
MOVING THROUGH THE BROAD TROUGH...WITH ONE NOW EAST OF THE UPPER
MISSISSIPPI VALLEY...AND THE NEXT APPROACHING THE NORTHERN/CENTRAL
HIGH PLAINS FROM THE WEST. AT THE SURFACE...AN AREA OF LOW PRESSURE
IS STARTING TO DEEPEN OVER CENTRAL MONTANA WITH HIGH PRESSURE
LOCATED OVER THE MISSOURI VALLEY. WHILE WINDS ARE FAIRLY LIGHT AND
VARIABLE AT THIS HOUR ACROSS THE CWA...FURTHER WEST ACROSS THE HIGH
PLAINS...SURFACE WINDS ARE STARTING TO TAKE ON A MORE SOUTHERLY
COMPONENT. TEMPERATURES EARLY THIS AM RANGE FROM A CHILLY 13
DEGREES FAHRENHEIT AT KLBF...TO AS WARM AS 30 AT KONL WHERE STRATUS
IS LOCKED IN PLACE.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH 12Z TUESDAY. MAIN FORECAST CONCERNS
OVER THE NEXT 72 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN
OF COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
WESTERN SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT
EAST ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT
THROUGH THE CWA LATE TODAY/OVERNIGHT TONIGHT. THE STRONGEST OMEGA
CONTINUES TO BE SUGGESTED WELL NORTH OF THE CWA...IN CLOSE VICINITY
TO THE TROUGH AXIS...HOWEVER MOST NEAR TERM MODEL SOLUTIONS GENERATE
LIGHT QPF AHEAD OF A MID-LEVEL FGEN BAND WHERE WEAK THERMAL
ADVECTION AND A BRIEF PERIOD OF UPGLIDE MAY BE SUFFICIENT ENOUGH TO
SQUEEZE OUT A HUNDREDTH OR TWO OF AN INCH OF PRECIPITATION THIS
AFTERNOON. THE BETTER DYNAMICS FOR PRECIPITATION PRODUCTION ARRIVES
WITH THE MID LEVEL FRONTOGENETIC BAND LATE THIS
AFTERNOON/EVENING...HOWEVER FORECAST PROXIMITY SOUNDINGS FROM ACROSS
THE CWA SUGGEST THE LOWER LEVELS OF THE ATMOSPHERE WILL QUICKLY DRY
OUT AS STRONG COLD/DRY AIR ADVECTION SPILLS IN BEHIND THE PASSING
BOUNDARY. THE ENSEMBLES...AND DETERMINISTIC SOLUTIONS ALL HAVE
CONVERGED THAT AT MOST LESS THAN .05 OF AN INCH OF QPF WOULD BE
GENERATED...SO ONLY LOOKING FOR A DUSTING TO POSSIBLY A HALF OF AN
INCH ACROSS THE SANDHILLS AND POINTS SOUTHEAST WHERE ADDITIONAL LIFT
MAY BE GENERATED WITHIN THE VICINITY OF THE RIGHT ENTRANCE OF A
PASSING UPPER JET. ACROSS NORTHERN NEBRASKA...THE NEAR TERM
CONSENSUS IS SUGGESTING A PERIOD OF POSSIBLE WRAP AROUND AS THE
SURFACE LOW ADVANCES INTO WEST CENTRAL MINNESOTA...THE POTENTIAL OF
SLIGHTLY HEAVIER SNOW ACCUMULATION EXIST...BUT LESS THAN AN INCH
WOULD BE EXPECT AT BEST WITH THE SNOW FALLING OVERNIGHT TONIGHT.
THE SHORTWAVE QUICKLY ADVANCES EAST OVERNIGHT BRINGING AN END TO
PRECIPITATION CHANCES FOR THE FORESEEABLE FUTURE AS AN OVERALL LACK
OF KINEMATIC FORCING IS SUGGESTED IN THE SHORT AND LONG TERM
SOLUTIONS.
STRONG COLD AIR ADVECTION AND MODEST LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW FOR
GUSTY CONDITIONS EARLY ON SUNDAY. THE MODELS HAVE SHOWN A SLIGHT
NORTHWARD TREND IN THE TRACK OF THE SURFACE LOW...NOW ACROSS WEST
CENTRAL MINNESOTA. THIS TRACK FAVORS SLIGHTLY WEAKER SURFACE WINDS
THAN PREVIOUSLY ANTICIPATED. SO WILL KEEP WIND SPEEDS BELOW
ADVISORY CRITERIA...ESPECIALLY SINCE THE STRONGEST PRESSURE RISES
ARE EXPECTED DURING THE EARLY MORNING HOURS...DIURNALLY UNFAVORABLE
FOR ADVISORY CRITERIA WIND. BUT...WIDESPREAD SUB ZERO WIND CHILLS
WILL BE POSSIBLE...WITH THE POTENTIAL OF SOME OF THE LOWEST READINGS
APPROACHING MINUS TEN OR COLDER AS H9 TEMPERATURES FALL AS COLD AS
MINUS 12C ACROSS OUR NORTHERN ZONES. HIGHS ON SUNDAY WILL BE
CHILLY...WITH READINGS RANGING FROM THE UPPER TEENS ACROSS THE
NORTH...TO THE UPPER 20S ACROSS THE FAR SOUTHWEST. WE WILL NEED TO
WATCH LOW TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD
ALLOW READINGS TO PLUMMET...TO POSSIBLY BELOW 0F. WILL KEEP
FORECAST VALUES IN THE SINGLE DIGITS FOR NOW...AS WIDESPREAD
ACCUMULATING SNOW IS NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE
SLOWLY MONDAY AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN
ADVANCE OF THE NEXT SHORTWAVE TROUGH.
LONG TERM...12Z TUESDAY AND BEYOND. THE NEXT WAVE PASSES THROUGH
EARLY TUESDAY...HOWEVER MOISTURE REMAINS IN QUESTION...AND KINEMATIC
FORCING REMAINS SOMEWHAT WEAK AND TO THE SOUTH...THUS CONFIDENCE IS
TOO LOW TO INTRODUCE POPS INTO THE FORECAST. OTHERWISE SHORTWAVE
RIDGING AND WAA TAKE HOLD THROUGH THE END OF NEXT WEEK...WITH
TEMPERATURES REMAINING NEAR TO SLIGHTLY ABOVE SEASONAL NORMS. THE
NEXT SIGNIFICANT TROUGH IS SHOWN TO ARRIVE ACROSS THE WEST LATE NEXT
WEEK...BUT WITH THIS EVENINGS MODEL RUNS...PRECIPITATION CHANCES
LOOK TO REMAIN WELL TO THE SOUTH AND WEST OF THE CWA.
AVIATION...
MVFR/LOCAL IFR CIGS ARE EXPECTED IN SOME AREAS TODAY AND TONIGHT.
THE RUC MODEL...WHICH HAS BEEN PERFORMING WELL...SHOWS THE MVFR/IFR
CIGS ACROSS NCNTL NEB LIFTING NORTH THIS AFTERNOON WITH MVFR CIGS
FILLING IN AGAIN AS AN ARCTIC FRONT MOVES INTO WRN/NCNTL NEB TONIGHT.
MEANWHILE A WARM FRONT DEVELOPING ACROSS SRN NEB THIS MORNING WILL
LIFT NORTH DURING THE DAY TODAY PRODUCING ISOLATED RAIN AND SNOW
SHOWERS AND LOCAL MVFR CIGS. ADDITIONAL SCATTERED SNOW SHOWERS/MVFR
CIGS ARE EXPECTED TONIGHT ALONG AND BEHIND THE ARCTIC FRONT.
WINDS ALONG AND BEHIND THE FRONT WILL INCREASE TO 32025G35KT TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
533 AM CST SAT DEC 8 2012
.UPDATE...
.AVIATION...
MVFR CIGS ARE EXPECTED IN SOME AREAS TODAY AND TONIGHT.
THE RUC MODEL...WHICH HAS BEEN PERFORMING WELL...SHOWS THE
MVFR/LOCAL IFR CIGS ACROSS NCNTL NEB LIFTING NORTH THIS AFTERNOON
WITH MVFR CIGS FILLING IN AGAIN TONIGHT AS AN ARCTIC FRONT MOVES
INTO WRN/NCNTL NEB.
MEANWHILE A WARM FRONT DEVELOPING ACROSS SRN NEB THIS MORNING WILL
LIFT NORTH DURING THE DAY TODAY PRODUCING ISOLATED RAIN AND SNOW
SHOWERS AND LOCAL MVFR CIGS. ADDITIONAL SCATTERED SNOW SHOWERS/MVFR
CIGS ARE EXPECTED TONIGHT ALONG AND BEHIND THE ARCTIC FRONT.
WINDS ALONG AND BEHIND THE FRONT WILL INCREASE TO 32025G35KT TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 400 AM CST SAT DEC 8 2012/
SYNOPSIS...
EVENING HAND ANALYSIS OF THE H5 LEVEL REVEALS A BROAD LONGWAVE
TROUGH ENCOMPASSING MUCH OF THE CONTIGUOUS 48...WITH RIDGING OFF
BOTH THE WESTERN AND EASTERN COASTS. SEVERAL SHORTWAVES ARE SEEN
MOVING THROUGH THE BROAD TROUGH...WITH ONE NOW EAST OF THE UPPER
MISSISSIPPI VALLEY...AND THE NEXT APPROACHING THE NORTHERN/CENTRAL
HIGH PLAINS FROM THE WEST. AT THE SURFACE...AN AREA OF LOW PRESSURE
IS STARTING TO DEEPEN OVER CENTRAL MONTANA WITH HIGH PRESSURE
LOCATED OVER THE MISSOURI VALLEY. WHILE WINDS ARE FAIRLY LIGHT AND
VARIABLE AT THIS HOUR ACROSS THE CWA...FURTHER WEST ACROSS THE HIGH
PLAINS...SURFACE WINDS ARE STARTING TO TAKE ON A MORE SOUTHERLY
COMPONENT. TEMPERATURES EARLY THIS AM RANGE FROM A CHILLY 13
DEGREES FAHRENHEIT AT KLBF...TO AS WARM AS 30 AT KONL WHERE STRATUS
IS LOCKED IN PLACE.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH 12Z TUESDAY. MAIN FORECAST CONCERNS
OVER THE NEXT 72 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN
OF COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
WESTERN SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT
EAST ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT
THROUGH THE CWA LATE TODAY/OVERNIGHT TONIGHT. THE STRONGEST OMEGA
CONTINUES TO BE SUGGESTED WELL NORTH OF THE CWA...IN CLOSE VICINITY
TO THE TROUGH AXIS...HOWEVER MOST NEAR TERM MODEL SOLUTIONS GENERATE
LIGHT QPF AHEAD OF A MID-LEVEL FGEN BAND WHERE WEAK THERMAL
ADVECTION AND A BRIEF PERIOD OF UPGLIDE MAY BE SUFFICIENT ENOUGH TO
SQUEEZE OUT A HUNDREDTH OR TWO OF AN INCH OF PRECIPITATION THIS
AFTERNOON. THE BETTER DYNAMICS FOR PRECIPITATION PRODUCTION ARRIVES
WITH THE MID LEVEL FRONTOGENETIC BAND LATE THIS
AFTERNOON/EVENING...HOWEVER FORECAST PROXIMITY SOUNDINGS FROM ACROSS
THE CWA SUGGEST THE LOWER LEVELS OF THE ATMOSPHERE WILL QUICKLY DRY
OUT AS STRONG COLD/DRY AIR ADVECTION SPILLS IN BEHIND THE PASSING
BOUNDARY. THE ENSEMBLES...AND DETERMINISTIC SOLUTIONS ALL HAVE
CONVERGED THAT AT MOST LESS THAN .05 OF AN INCH OF QPF WOULD BE
GENERATED...SO ONLY LOOKING FOR A DUSTING TO POSSIBLY A HALF OF AN
INCH ACROSS THE SANDHILLS AND POINTS SOUTHEAST WHERE ADDITIONAL LIFT
MAY BE GENERATED WITHIN THE VICINITY OF THE RIGHT ENTRANCE OF A
PASSING UPPER JET. ACROSS NORTHERN NEBRASKA...THE NEAR TERM
CONSENSUS IS SUGGESTING A PERIOD OF POSSIBLE WRAP AROUND AS THE
SURFACE LOW ADVANCES INTO WEST CENTRAL MINNESOTA...THE POTENTIAL OF
SLIGHTLY HEAVIER SNOW ACCUMULATION EXIST...BUT LESS THAN AN INCH
WOULD BE EXPECT AT BEST WITH THE SNOW FALLING OVERNIGHT TONIGHT.
THE SHORTWAVE QUICKLY ADVANCES EAST OVERNIGHT BRINGING AN END TO
PRECIPITATION CHANCES FOR THE FORESEEABLE FUTURE AS AN OVERALL LACK
OF KINEMATIC FORCING IS SUGGESTED IN THE SHORT AND LONG TERM
SOLUTIONS.
STRONG COLD AIR ADVECTION AND MODEST LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW FOR
GUSTY CONDITIONS EARLY ON SUNDAY. THE MODELS HAVE SHOWN A SLIGHT
NORTHWARD TREND IN THE TRACK OF THE SURFACE LOW...NOW ACROSS WEST
CENTRAL MINNESOTA. THIS TRACK FAVORS SLIGHTLY WEAKER SURFACE WINDS
THAN PREVIOUSLY ANTICIPATED. SO WILL KEEP WIND SPEEDS BELOW
ADVISORY CRITERIA...ESPECIALLY SINCE THE STRONGEST PRESSURE RISES
ARE EXPECTED DURING THE EARLY MORNING HOURS...DIURNALLY UNFAVORABLE
FOR ADVISORY CRITERIA WIND. BUT...WIDESPREAD SUB ZERO WIND CHILLS
WILL BE POSSIBLE...WITH THE POTENTIAL OF SOME OF THE LOWEST READINGS
APPROACHING MINUS TEN OR COLDER AS H9 TEMPERATURES FALL AS COLD AS
MINUS 12C ACROSS OUR NORTHERN ZONES. HIGHS ON SUNDAY WILL BE
CHILLY...WITH READINGS RANGING FROM THE UPPER TEENS ACROSS THE
NORTH...TO THE UPPER 20S ACROSS THE FAR SOUTHWEST. WE WILL NEED TO
WATCH LOW TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD
ALLOW READINGS TO PLUMMET...TO POSSIBLY BELOW 0F. WILL KEEP
FORECAST VALUES IN THE SINGLE DIGITS FOR NOW...AS WIDESPREAD
ACCUMULATING SNOW IS NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE
SLOWLY MONDAY AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN
ADVANCE OF THE NEXT SHORTWAVE TROUGH.
LONG TERM...12Z TUESDAY AND BEYOND. THE NEXT WAVE PASSES THROUGH
EARLY TUESDAY...HOWEVER MOISTURE REMAINS IN QUESTION...AND KINEMATIC
FORCING REMAINS SOMEWHAT WEAK AND TO THE SOUTH...THUS CONFIDENCE IS
TOO LOW TO INTRODUCE POPS INTO THE FORECAST. OTHERWISE SHORTWAVE
RIDGING AND WAA TAKE HOLD THROUGH THE END OF NEXT WEEK...WITH
TEMPERATURES REMAINING NEAR TO SLIGHTLY ABOVE SEASONAL NORMS. THE
NEXT SIGNIFICANT TROUGH IS SHOWN TO ARRIVE ACROSS THE WEST LATE NEXT
WEEK...BUT WITH THIS EVENINGS MODEL RUNS...PRECIPITATION CHANCES
LOOK TO REMAIN WELL TO THE SOUTH AND WEST OF THE CWA.
AVIATION...
MVFR/LOCAL IFR CIGS ARE EXPECTED IN SOME AREAS TODAY AND TONIGHT.
THE RUC MODEL...WHICH HAS BEEN PERFORMING WELL...SHOWS THE MVFR/IFR
CIGS ACROSS NCNTL NEB LIFTING NORTH THIS AFTERNOON WITH MVFR CIGS
FILLING IN AGAIN AS AN ARCTIC FRONT MOVES INTO WRN/NCNTL NEB TONIGHT.
MEANWHILE A WARM FRONT DEVELOPING ACROSS SRN NEB THIS MORNING WILL
LIFT NORTH DURING THE DAY TODAY PRODUCING ISOLATED RAIN AND SNOW
SHOWERS AND LOCAL MVFR CIGS. ADDITIONAL SCATTERED SNOW SHOWERS/MVFR
CIGS ARE EXPECTED TONIGHT ALONG AND BEHIND THE ARCTIC FRONT.
WINDS ALONG AND BEHIND THE FRONT WILL INCREASE TO 32025G35KT TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
400 AM CST SAT DEC 8 2012
.SYNOPSIS...
EVENING HAND ANALYSIS OF THE H5 LEVEL REVEALS A BROAD LONGWAVE
TROUGH ENCOMPASSING MUCH OF THE CONTIGUOUS 48...WITH RIDGING OFF
BOTH THE WESTERN AND EASTERN COASTS. SEVERAL SHORTWAVES ARE SEEN
MOVING THROUGH THE BROAD TROUGH...WITH ONE NOW EAST OF THE UPPER
MISSISSIPPI VALLEY...AND THE NEXT APPROACHING THE NORTHERN/CENTRAL
HIGH PLAINS FROM THE WEST. AT THE SURFACE...AN AREA OF LOW PRESSURE
IS STARTING TO DEEPEN OVER CENTRAL MONTANA WITH HIGH PRESSURE
LOCATED OVER THE MISSOURI VALLEY. WHILE WINDS ARE FAIRLY LIGHT AND
VARIABLE AT THIS HOUR ACROSS THE CWA...FURTHER WEST ACROSS THE HIGH
PLAINS...SURFACE WINDS ARE STARTING TO TAKE ON A MORE SOUTHERLY
COMPONENT. TEMPERATURES EARLY THIS AM RANGE FROM A CHILLY 13
DEGREES FAHRENHEIT AT KLBF...TO AS WARM AS 30 AT KONL WHERE STRATUS
IS LOCKED IN PLACE.
&&
.DISCUSSION...
SHORT TERM...TONIGHT THROUGH 12Z TUESDAY. MAIN FORECAST CONCERNS
OVER THE NEXT 72 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN
OF COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
WESTERN SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT
EAST ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT
THROUGH THE CWA LATE TODAY/OVERNIGHT TONIGHT. THE STRONGEST OMEGA
CONTINUES TO BE SUGGESTED WELL NORTH OF THE CWA...IN CLOSE VICINITY
TO THE TROUGH AXIS...HOWEVER MOST NEAR TERM MODEL SOLUTIONS GENERATE
LIGHT QPF AHEAD OF A MID-LEVEL FGEN BAND WHERE WEAK THERMAL
ADVECTION AND A BRIEF PERIOD OF UPGLIDE MAY BE SUFFICIENT ENOUGH TO
SQUEEZE OUT A HUNDREDTH OR TWO OF AN INCH OF PRECIPITATION THIS
AFTERNOON. THE BETTER DYNAMICS FOR PRECIPITATION PRODUCTION ARRIVES
WITH THE MID LEVEL FRONTOGENETIC BAND LATE THIS
AFTERNOON/EVENING...HOWEVER FORECAST PROXIMITY SOUNDINGS FROM ACROSS
THE CWA SUGGEST THE LOWER LEVELS OF THE ATMOSPHERE WILL QUICKLY DRY
OUT AS STRONG COLD/DRY AIR ADVECTION SPILLS IN BEHIND THE PASSING
BOUNDARY. THE ENSEMBLES...AND DETERMINISTIC SOLUTIONS ALL HAVE
CONVERGED THAT AT MOST LESS THAN .05 OF AN INCH OF QPF WOULD BE
GENERATED...SO ONLY LOOKING FOR A DUSTING TO POSSIBLY A HALF OF AN
INCH ACROSS THE SANDHILLS AND POINTS SOUTHEAST WHERE ADDITIONAL LIFT
MAY BE GENERATED WITHIN THE VICINITY OF THE RIGHT ENTRANCE OF A
PASSING UPPER JET. ACROSS NORTHERN NEBRASKA...THE NEAR TERM
CONSENSUS IS SUGGESTING A PERIOD OF POSSIBLE WRAP AROUND AS THE
SURFACE LOW ADVANCES INTO WEST CENTRAL MINNESOTA...THE POTENTIAL OF
SLIGHTLY HEAVIER SNOW ACCUMULATION EXIST...BUT LESS THAN AN INCH
WOULD BE EXPECT AT BEST WITH THE SNOW FALLING OVERNIGHT TONIGHT.
THE SHORTWAVE QUICKLY ADVANCES EAST OVERNIGHT BRINGING AN END TO
PRECIPITATION CHANCES FOR THE FORESEEABLE FUTURE AS AN OVERALL LACK
OF KINEMATIC FORCING IS SUGGESTED IN THE SHORT AND LONG TERM
SOLUTIONS.
STRONG COLD AIR ADVECTION AND MODEST LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW FOR
GUSTY CONDITIONS EARLY ON SUNDAY. THE MODELS HAVE SHOWN A SLIGHT
NORTHWARD TREND IN THE TRACK OF THE SURFACE LOW...NOW ACROSS WEST
CENTRAL MINNESOTA. THIS TRACK FAVORS SLIGHTLY WEAKER SURFACE WINDS
THAN PREVIOUSLY ANTICIPATED. SO WILL KEEP WIND SPEEDS BELOW
ADVISORY CRITERIA...ESPECIALLY SINCE THE STRONGEST PRESSURE RISES
ARE EXPECTED DURING THE EARLY MORNING HOURS...DIURNALLY UNFAVORABLE
FOR ADVISORY CRITERIA WIND. BUT...WIDESPREAD SUB ZERO WIND CHILLS
WILL BE POSSIBLE...WITH THE POTENTIAL OF SOME OF THE LOWEST READINGS
APPROACHING MINUS TEN OR COLDER AS H9 TEMPERATURES FALL AS COLD AS
MINUS 12C ACROSS OUR NORTHERN ZONES. HIGHS ON SUNDAY WILL BE
CHILLY...WITH READINGS RANGING FROM THE UPPER TEENS ACROSS THE
NORTH...TO THE UPPER 20S ACROSS THE FAR SOUTHWEST. WE WILL NEED TO
WATCH LOW TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD
ALLOW READINGS TO PLUMMET...TO POSSIBLY BELOW 0F. WILL KEEP
FORECAST VALUES IN THE SINGLE DIGITS FOR NOW...AS WIDESPREAD
ACCUMULATING SNOW IS NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE
SLOWLY MONDAY AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN
ADVANCE OF THE NEXT SHORTWAVE TROUGH.
LONG TERM...12Z TUESDAY AND BEYOND. THE NEXT WAVE PASSES THROUGH
EARLY TUESDAY...HOWEVER MOISTURE REMAINS IN QUESTION...AND KINEMATIC
FORCING REMAINS SOMEWHAT WEAK AND TO THE SOUTH...THUS CONFIDENCE IS
TOO LOW TO INTRODUCE POPS INTO THE FORECAST. OTHERWISE SHORTWAVE
RIDGING AND WAA TAKE HOLD THROUGH THE END OF NEXT WEEK...WITH
TEMPERATURES REMAINING NEAR TO SLIGHTLY ABOVE SEASONAL NORMS. THE
NEXT SIGNIFICANT TROUGH IS SHOWN TO ARRIVE ACROSS THE WEST LATE NEXT
WEEK...BUT WITH THIS EVENINGS MODEL RUNS...PRECIPITATION CHANCES
LOOK TO REMAIN WELL TO THE SOUTH AND WEST OF THE CWA.
&&
.AVIATION...
MVFR/LOCAL IFR CIGS ARE EXPECTED IN SOME AREAS TODAY AND TONIGHT.
THE RUC MODEL...WHICH HAS BEEN PERFORMING WELL...SHOWS THE MVFR/IFR
CIGS ACROSS NCNTL NEB LIFTING NORTH THIS AFTERNOON WITH MVFR CIGS
FILLING IN AGAIN AS AN ARCTIC FRONT MOVES INTO WRN/NCNTL NEB TONIGHT.
MEANWHILE A WARM FRONT DEVELOPING ACROSS SRN NEB THIS MORNING WILL
LIFT NORTH DURING THE DAY TODAY PRODUCING ISOLATED RAIN AND SNOW
SHOWERS AND LOCAL MVFR CIGS. ADDITIONAL SCATTERED SNOW SHOWERS/MVFR
CIGS ARE EXPECTED TONIGHT ALONG AND BEHIND THE ARCTIC FRONT.
WINDS ALONG AND BEHIND THE FRONT WILL INCREASE TO 32025G35KT TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1029 PM EST SUN DEC 9 2012
.SYNOPSIS...
PERIODS OF RAIN CAN BE EXPECTED ACROSS THE AREA THROUGH MONDAY AS
A SLOW MOVING COLD FRONT TRACKS EAST ACROSS THE AREA. THE
PRECIPIATION COULD END AS A BRIEF PERIOD OF SNOW SHOWERS MONDAY
NIGHT AS COLD AIR MOVES IN. TUESDAY WILL BE MOSTLY DRY AND CHILLY
AS HIGH PRESSURE BUILDS ACROSS THE AREA. WARMER AND CONTINUED DRY
WEATHER CAN BE EXPECTED WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
10 PM UPDATE...JUST TWEAKED GRIDS SOME. DECIDED TO WIND DOWN POPS
FOR A FEW HOURS BETWEEN FIRST SHRT WAVE PASSING BY AT PRESENT AND
THEN NEXT ONE WHICH IS MOVING TWD PA. PRECIPITATION ECHOES WINDING
DOWN ON KBGM RADAR AS THEY ARE BEGINNING TO INCREASE IN SRN PA ON
THE KCCX RADAR. SO WILL BRING POPS BACK UP WITH THE ARRIVAL OF
THIS NEXT WAVE AND PRECIP FROM PA LATE TONIGHT. AS FOR PRECIP TYPE...
KTYX RADAR DUAL POLAR PRODUCTS SUGGEST A MELTING LAYER ARND 4800
FEET IN NRN ONEIDA COUNTY. SURFACE MESONETS SHOW TEMPERATURES A
LITTLE ABV FREEZING SUGGESTING JUST PLAIN RAIN UP THERE. HAVE AN
SPS THAT WILL EXPIRE AT 11 PM FOR POTENTIAL FOR FZRA AT THE ONSET
OF THE PRECIP. WILL LET THIS EXPIRE. NRN ONEIDA WILL SEE RAIN THRU THE
NIGHT AS TEMPS CLIMB WITH CONTINUED WARMING ALOFT. ALSO MESONETS IN
THE CATSKILLS SHOW TEMPS ABV FRZG. AS THE TEMPERATURES AT 850 MB
ROCKET UP TO +5C OR SO...TEMPS WILL CONT TO SLOWLY WARM OVERNIGHT.
BIG CHANGE FOR MONDAY WAS TO DROP POPS TO CHC-SLGHT CHC IN THE AM
HOURS AS ALL CONVECTION ALLOWING MODELS AND OTHER HI RES MODELS
SHOW LITTLE PRECIP AT ALL UNTIL CD FRNT APPROACHES IN THE
AFTERNOON. SO WILL BEGIN THE DAY WITH JUST ISLD-SCT SHRA AT BEST...AND
RAMP UP POPS TO CAT IN THE AFTERNOON.
PREVIOUS DISCUSSION BELOW...
7 PM UPDATE...ISSUED A SPECIAL WEATHER STATEMENT FOR THE WESTERN
CATSKILLS AND NORTHERN ONEIDA COUNTY FOR A BRIEF PERIOD OF
FREEZING RAIN. RAIN WILL OVERSPREAD THE REGION QUICKLY BY 3-4Z AS
A STRONG SHOT OF LOW-LEVEL MOISTURE ADVECTION AND ISENTROPIC
LIFT/WAA RAPIDLY LEADS TO WIDESPREAD LIGHT RAINS OVER THE AREA. A
FEW HIGHER TERRAIN SPOTS IN THE CATSKILLS AND FAR NORTHEAST ONEIDA
COUNTY COULD BEGIN AS A PERIOD OF FREEZING RAIN AS TEMPERATURES
LIKELY ARE CLOSE TO FREEZING IN THESE AREAS. IT WILL BE VERY
SPOTTY SO NO FZRA ADVY. DUE TO THE STRONG ISENTROPIC LIFT/WARM AIR
ADVECTION...TEMPERATURES SOAR TO 3-7C AT 850 MB BY 6Z AS PER
GFS...WITH SIMILAR TEMPERATURES ON THE NAM...CMC...RAP...AND LOCAL
WRF. THIS WARMING SHUD ALLOW TEMPERATURES TO CLIMB TO THE MID TO
UPPER 30S OR EVEN LOW 40S OVERNIGHT AS THE RAIN FALLS.
FIRST SHOT OF RAIN LIKELY WILL MOVE QUICKLY THRU C NY AND NE PA BY
6-7Z WITH THE NEXT SHOT RAPIDLY APPROACHING ARND 9Z-10Z OR SO AS
ANOTHER LOW-LEVEL JET AND ASSOCIATED MOISTURE ADVECTION AND
ENHANCED ISENTROPIC LIFT APPROACHES. THE WATER VAPOR SATELLITE
IMAGERY SHOWS THESE TWO LOWER-LEVEL WAVES WELL IN THE UPPER LEVEL
MOIST PLUMES...ONE NORTH OF NY AND THE OTHER ACRS THE OH VLLY TO
MID ATLANTIC. THE MODELS HAVE TWO DISTINCTS LOW-LEVEL JETS AT 850
MB WHICH ARE TIED TO EACH OF THESE SHORT WAVES. HENCE PRECIP
INCREASES AGAIN LATE TONIGHT WITH NEXT WAVE. .
THEN FOR MONDAY MORNING AFTER THE SECOND WAVE...I SEE A BREAK IN
THE PRECIPITATION BEFORE THE RAIN SHOWERS MOVE THRU THE REGION
ALONG A COLD FRONT WHICH SWINGS THRU IN THE AFTERNOON. THE HIGH
RES WRF ARW AND WRF NMM...LOCAL WRF...RAP AND NAM 4KM ALL SHOW
LITTLE PRECIP MONDAY AM WITH PRECIP INCREASING AGAIN IN THE PM. FOR
NOW DO NOT HAVE THUNDER IN GRIDS FOR MONDAY AFTERNOON...BUT NAM
AND RAP SHOWALTERS ARE SLIGHT NEGATIVE...LOCAL WRF AND GFS ARE
SLIGHTLY POSITIVE. THE HI RES CONVECTION ALLOWING MODELS ALL SHOW
SOME SORT OF LINE OF HEAVIER SHRA ALONG THE COLD FRONT MON PM. SO
I TRENDED POPS DOWNWARD MONDAY AM...THEN INCREASED THEM IN THE
AFTERNOON TO ACCOUNT FOR CD FRONTL SHRA ACVTY. WILL PASS ON IDEA
OF POSSIBLE THUNDER TO MID SHIFT WHICH WILL HAVE THE NEW 00Z
GUIDC TO LOOK AT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
COLD FRONT APPROACHES THE AREA ON MONDAY. WITH SURFACE LOW
PRESSURE TRACKING UP THE ST LAWRENCE VALLEY OUR AREA WILL BE IN
THE WARM SECTOR MONDAY WITH STEADIER RAIN PULLING OFF TO THE NORTH
AND EAST FOR AWHILE MONDAY MORNING INTO THE AFTERNOON. BASED ON
THIS EXPECT RAIN TO TAPER TO SHOWERS ESPECIALLY OVER NORTHEAST PA.
TEMPERATURES WILL CLIMB WELL INTO THE 50S.
COLD FRONT CROSS THE AREA STARTING AROUND 18Z OVER STEUBEN
COUNTY... AND AROUND 00Z OVER NORTHEAST PA. THIS WILL BE
ACCOMPANIED BY AND FOLLOWED BY A PERIOD OF HEAVIER RAIN. THE RAIN
MAY CHANGE TO A PERIOD OF LIGHT SNOW OVER CENTRAL NY AFTER OOZ AS
WEAK WAVES OF LOW PRESSURE MOVING NORTHEAST ALONG THE FRONT MAY
KEEP THE PRECIPITATION GOING FOR AWHILE MONDAY EVENING IN THE COLD
AIR. TEMPERATURES BRIEFLY COOL TO AROUND -10 AT 850 MB WHICH WILL
BE ENOUGH FOR A BRIEF LAKE RESPONSE LATER MONDAY NIGHT NW FLOW AND
SOME SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO. OVERALL
ACCUMULATIONS OF SNOW MONDAY NIGHT SHOULD BE LESS THAN 2 INCHES.
HIGH PRESSURE MOVES ACROSS THE AREA ON TUESDAY WITH DRY WEATHER
AND SEASONABLY COLD TEMPERATURES. WARMING TREND BEGINS ON
WEDNESDAY AS THE HIGH MOVES OFF TO THE EAST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT THROUGH THE EXTENDED
INDICATING SURFACE HIGH PRESSURE WILL PROVIDE DRY AND MILD
CONDITIONS THROUGH FRIDAY. LATE IN THE PERIOD LOW PRES IS FORECAST
TO TRACK FROM THE MID WEST NORTHEAST INTO THE UPPER GREAT LAKES
THEN ACROSS EASTERN CANADA. THE ECMWF IS SLOWER AND FARTHER WEST
WITH THIS SYSTEM THAN THE GFS. WILL CONTINUE WITH CHC POPS
SATURDAY THROUGH SUNDAY WITH PRECIP TYPE A RAIN/SNOW MIX CHANGING
TO ALL RAIN BY SUNDAY AS TEMPS WARM INTO THE LOWER/MIDDLE 40S.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
LOW PRESSURE WILL TRACK ACROSS THE LOWER GREAT LAKES TONIGHT...AND
UP THE ST. LAWRENCE RIVER VALLEY ON MONDAY. A WARM FRONT WILL MOVE
ACROSS CENTRAL NY AND NORTHEAST PA TONIGHT. AREAS OF RAIN WILL
SLIDE THROUGH THE REGION DURING THE NEXT 12-24 HOURS WITH IFR AND
OTHER FUEL ALTERNATE MINIMUM RESTRICTIONS TO CEILINGS. VISIBILITIES
SHOULD BE SLIGHTLY BETTER IN CATEGORY WITH FLUCTUATIONS BETWEEN
VFR-MVFR.
WINDS WILL BE PREDOMINANTLY E-SE 5-10 KTS OVERNIGHT BUT A STABLE
BOUNDARY LAYER WILL KEEP DEEP VALLEY FLOWS AT KAVP-KELM LIGHT
AND VARIABLE. A STRONG CORRIDOR OF S-SW FLOW IS EXPECTED TO
DEVELOP ALOFT THIS EVENING WHICH COULD POSE A LLWS PROBLEM
FOR THE LIGHTER SFC WIND STATIONS WITH TOP OF INVERSION WINDS
AROUND 40-45 KTS. ON MONDAY...SW WINDS DEVELOP WITH BETTER MIXING
AT 10-15 KTS WITH A LATE PERIOD WIND SHIFT TO THE WEST-NW
ASSOCIATED WITH COLD FRONTAL PASSAGE.
OUTLOOK...
MON EVNG...IFR/MVFR WITH PERIODS OF RAIN ENDING.
LATE MON NGT/TUE...PATCHY MVFR...MAINLY ACRS CNTRL NY.
TUE NGT-FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...DJN
SHORT TERM...MSE
LONG TERM...RRM
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
759 PM EST SUN DEC 9 2012
.SYNOPSIS...
PERIODS OF RAIN CAN BE EXPECTED ACROSS THE AREA THROUGH MONDAY AS
A SLOW MOVING COLD FRONT TRACKS EAST ACROSS THE AREA. THE
PRECIPIATION COULD END AS A BRIEF PERIOD OF SNOW SHOWERS MONDAY
NIGHT AS COLD AIR MOVES IN. TUESDAY WILL BE MOSTLY DRY AND CHILLY
AS HIGH PRESSURE BUILDS ACROSS THE AREA. WARMER AND CONTINUED DRY
WEATHER CAN BE EXPECTED WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
7 PM UPDATE...ISSUED A SPECIAL WEATHER STATEMENT FOR THE WESTERN
CATSKILLS AND NORTHERN ONEIDA COUNTY FOR A BRIEF PERIOD OF
FREEZING RAIN. RAIN WILL OVERSPREAD THE REGION QUICKLY BY 3-4Z AS
A STRONG SHOT OF LOW-LEVEL MOISTURE ADVECTION AND ISENTROPIC LIFT/WAA
RAPIDLY LEADS TO WIDESPREAD LIGHT RAINS OVER THE AREA. A FEW
HIGHER TERRAIN SPOTS IN THE CATSKILLS AND FAR NORTHEAST ONEIDA
COUNTY COULD BEGIN AS A PERIOD OF FREEZING RAIN AS TEMPERATURES
LIKELY ARE CLOSE TO FREEZING IN THESE AREAS. IT WILL BE VERY
SPOTTY SO NO FZRA ADVY. DUE TO THE STRONG ISENTROPIC LIFT/WARM AIR
ADVECTION...TEMPERATURES SOAR TO 3-7C AT 850 MB BY 6Z AS PER
GFS...WITH SIMILAR TEMPERATURES ON THE NAM...CMC...RAP...AND LOCAL
WRF. THIS WARMING SHUD ALLOW TEMPERATURES TO CLIMB TO THE MID TO
UPPER 30S OR EVEN LOW 40S OVERNIGHT AS THE RAIN FALLS.
FIRST SHOT OF RAIN LIKELY WILL MOVE QUICKLY THRU C NY AND NE PA BY
6-7Z WITH THE NEXT SHOT RAPIDLY APPROACHING ARND 9Z-10Z OR SO AS
ANOTHER LOW-LEVEL JET AND ASSOCIATED MOISTURE ADVECTION AND
ENHANCED ISENTROPIC LIFT APPROACHES. THE WATER VAPOR SATELLITE
IMAGERY SHOWS THESE TWO LOWER-LEVEL WAVES WELL IN THE UPPER LEVEL
MOIST PLUMES...ONE NORTH OF NY AND THE OTHER ACRS THE OH VLLY TO
MID ATLANTIC. THE MODELS HAVE TWO DISTINCTS LOW-LEVEL JETS AT 850
MB WHICH ARE TIED TO EACH OF THESE SHORT WAVES. HENCE PRECIP
INCREASES AGAIN LATE TONIGHT WITH NEXT WAVE. .
THEN FOR MONDAY MORNING AFTER THE SECOND WAVE...I SEE A BREAK IN
THE PRECIPITATION BEFORE THE RAIN SHOWERS MOVE THRU THE REGION
ALONG A COLD FRONT WHICH SWINGS THRU IN THE AFTERNOON. THE HIGH
RES WRF ARW AND WRF NMM...LOCAL WRF...RAP AND NAM 4KM ALL SHOW
LITTLE PRECIP MONDAY AM WITH PRECIP INCREASING AGAIN IN THE PM. FOR
NOW DO NOT HAVE THUNDER IN GRIDS FOR MONDAY AFTERNOON...BUT NAM
AND RAP SHOWALTERS ARE SLIGHT NEGATIVE...LOCAL WRF AND GFS ARE
SLIGHTLY POSITIVE. THE HI RES CONVECTION ALLOWING MODELS ALL SHOW
SOME SORT OF LINE OF HEAVIER SHRA ALONG THE COLD FRONT MON PM. SO
I TRENDED POPS DOWNWARD MONDAY AM...THEN INCREASED THEM IN THE
AFTERNOON TO ACCOUNT FOR CD FRONTL SHRA ACVTY. WILL PASS ON IDEA
OF POSSIBLE THUNDER TO MID SHIFT WHICH WILL HAVE THE NEW 00Z
GUIDC TO LOOK AT.
PREVIOUS DISCUSSION BELOW...
CURRENTLY WATCHING DISORGANIZED AREA OF LIGHT SHOWERS MOVING EAST
ACROSS NORTHEAST PA AND THE WESTERN FINGER LAKES AREA. SOME
REPORTS EARLIER THIS AFTERNOON INDICATED A LITTLE SLEET MIXING
WITH THE RAIN OVER THE POCONOS... ALTHOUGH WITH TEMPERATURES WELL
ABOVE FREEZING. STRONGER AREA OF ISENTROPIC LIFT WILL OVERSPREAD
THE AREA TOWARD 00Z WITH MORE WIDESPREAD PRECIPITATION EXPECTED TO
DEVELOP ACROSS THE AREA AROUND THAT TIME. LATEST OBSERVATIONAL
TRENDS INDICATE MOST IF NOT ALL OF THE AREA WILL BE ABOVE FREEZING
AS THIS PRECIPITATION DEVELOPS. LATEST OBSERVATIONS SHOW RME WITH
A TEMPERATURE OF 40 AND A DEW PT OF 31... WITH MILD AIR STILL TO
THE EAST OVER THE HUDSON VALLEY AND EASTERN MOHAWK VALLEY. COLD
AIR IS OVER AND NORTH OF THE ADIRONDACKS BUT EXPECT THAT THIS WILL
HAVE A HARD TIME GETTING DOWN INTO THE MOHAWK VALLEY DURING THE
NEXT SEVERAL HOURS. LATEST LAV TEMPERATURES INDICATE A FEW
LOCATIONS GETTING TO AROUND 31 OR 32 IN THE HIGHER ELEVATIONS OF
THE WESTERN / NORTHWESTERN CATSKILLS... BUT THIS GUIDANCE ALONG
WITH HI RESOLUTION MODEL LOW- LEVEL TEMPERATURES INDICATE LITTLE
IF ANY FREEZING RAIN POTENTIAL IN OUR COUNTIES. THEREFORE HAVE
DECIDED NOT TO GO WITH ANY ADVISORIES... ALTHOUGH CAN`T RULE OUT A
BRIEF PERIOD OF 32 DEGREE RAIN IN A FEW ISOLATED POCKETS OVER THE
FAR NORTH AND EAST. WIDESPREAD RAIN WILL AFFECT MUCH OF THE AREA
OVERNIGHT IN FAVORABLE ISENTROPIC LIFT PATTERN WITH A 30 TO 40 KT
LOW-LEVEL JET. SOME WIND GUSTS OF 30 TO 35 KT MAY OCCUR AT HIGHER
ELEVATIONS OVERNIGHT BUT WINDS SHOULD REMAIN BELOW ADVISORY
CRITERIA.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
COLD FRONT APPROACHES THE AREA ON MONDAY. WITH SURFACE LOW
PRESSURE TRACKING UP THE ST LAWRENCE VALLEY OUR AREA WILL BE IN
THE WARM SECTOR MONDAY WITH STEADIER RAIN PULLING OFF TO THE NORTH
AND EAST FOR AWHILE MONDAY MORNING INTO THE AFTERNOON. BASED ON
THIS EXPECT RAIN TO TAPER TO SHOWERS ESPECIALLY OVER NORTHEAST PA.
TEMPERATURES WILL CLIMB WELL INTO THE 50S.
COLD FRONT CROSS THE AREA STARTING AROUND 18Z OVER STEUBEN
COUNTY... AND AROUND 00Z OVER NORTHEAST PA. THIS WILL BE
ACCOMPANIED BY AND FOLLOWED BY A PERIOD OF HEAVIER RAIN. THE RAIN
MAY CHANGE TO A PERIOD OF LIGHT SNOW OVER CENTRAL NY AFTER OOZ AS
WEAK WAVES OF LOW PRESSURE MOVING NORTHEAST ALONG THE FRONT MAY
KEEP THE PRECIPITATION GOING FOR AWHILE MONDAY EVENING IN THE COLD
AIR. TEMPERATURES BRIEFLY COOL TO AROUND -10 AT 850 MB WHICH WILL
BE ENOUGH FOR A BRIEF LAKE RESPONSE LATER MONDAY NIGHT NW FLOW AND
SOME SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO. OVERALL
ACCUMULATIONS OF SNOW MONDAY NIGHT SHOULD BE LESS THAN 2 INCHES.
HIGH PRESSURE MOVES ACROSS THE AREA ON TUESDAY WITH DRY WEATHER
AND SEASONABLY COLD TEMPERATURES. WARMING TREND BEGINS ON
WEDNESDAY AS THE HIGH MOVES OFF TO THE EAST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT THROUGH THE EXTENDED
INDICATING SURFACE HIGH PRESSURE WILL PROVIDE DRY AND MILD
CONDITIONS THROUGH FRIDAY. LATE IN THE PERIOD LOW PRES IS FORECAST
TO TRACK FROM THE MID WEST NORTHEAST INTO THE UPPER GREAT LAKES
THEN ACROSS EASTERN CANADA. THE ECMWF IS SLOWER AND FARTHER WEST
WITH THIS SYSTEM THAN THE GFS. WILL CONTINUE WITH CHC POPS
SATURDAY THROUGH SUNDAY WITH PRECIP TYPE A RAIN/SNOW MIX CHANGING
TO ALL RAIN BY SUNDAY AS TEMPS WARM INTO THE LOWER/MIDDLE 40S.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
LOW PRESSURE WILL TRACK ACROSS THE LOWER GREAT LAKES TONIGHT...AND
UP THE ST. LAWRENCE RIVER VALLEY ON MONDAY. A WARM FRONT WILL MOVE
ACROSS CENTRAL NY AND NORTHEAST PA TONIGHT. AREAS OF RAIN WILL
SLIDE THROUGH THE REGION DURING THE NEXT 12-24 HOURS WITH IFR AND
OTHER FUEL ALTERNATE MINIMUM RESTRICTIONS TO CEILINGS. VISIBILITIES
SHOULD BE SLIGHTLY BETTER IN CATEGORY WITH FLUCTUATIONS BETWEEN
VFR-MVFR.
WINDS WILL BE PREDOMINANTLY E-SE 5-10 KTS OVERNIGHT BUT A STABLE
BOUNDARY LAYER WILL KEEP DEEP VALLEY FLOWS AT KAVP-KELM LIGHT
AND VARIABLE. A STRONG CORRIDOR OF S-SW FLOW IS EXPECTED TO
DEVELOP ALOFT THIS EVENING WHICH COULD POSE A LLWS PROBLEM
FOR THE LIGHTER SFC WIND STATIONS WITH TOP OF INVERSION WINDS
AROUND 40-45 KTS. ON MONDAY...SW WINDS DEVELOP WITH BETTER MIXING
AT 10-15 KTS WITH A LATE PERIOD WIND SHIFT TO THE WEST-NW
ASSOCIATED WITH COLD FRONTAL PASSAGE.
OUTLOOK...
MON EVNG...IFR/MVFR WITH PERIODS OF RAIN ENDING.
LATE MON NGT/TUE...PATCHY MVFR...MAINLY ACRS CNTRL NY.
TUE NGT-FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...DJN/MSE
SHORT TERM...MSE
LONG TERM...RRM
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
930 PM EST SUN DEC 9 2012
.SYNOPSIS...
A WARM SOUTHERLY FLOW WILL PREVAIL OVER THE REGION THROUGH MONDAY...
AHEAD OF A COLD FRONT APPROACHING FROM THE WEST. THE COLD FRONT WILL
PUSH EAST THROUGH THE AREA LATE MONDAY NIGHT... BEFORE MOVING TO THE
COAST TUESDAY MORNING. LOW PRESSURE WILL THEN TRACK ALONG THE FRONT
NEAR THE CAROLINA COAST... KEEPING WEATHER COOL AND UNSETTLED
THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 930 PM SUNDAY...
WHILE THE FRONTAL ZONE WEST OF THE MOUNTAINS HAS TEMPORARILY LIFTED
NORTH INTO THE OH VALLEY AS A WARM FRONT THIS EVENING...A WEDGE-LIKE
AIRMASS IS LINGERING OVER VA...WITH THE SURFACE FRONT NEAR THE NC/VA
BORDER. NORTH OF THE FRONT...DENSE FOG HAS ALREADY SET IN. WARM
ADVECTION ATOP THE NOCTURNAL STABLE LAYER SHOULD STRENGTHEN THE
INVERSION...BUT THERE IS VERY LITTLE PRECIP HELPING TO FURTHER LOCK
IN THE AIRMASS. THE RAP SHOWS A SOUTHERN WIND PUSHING INTO VA
OVERNIGHT...BUT THIS MAY BE A LITTLE AGGRESSIVE. THUS..WITH THE
BOUNDARY SO CLOSE TOP THE CWA...HAVE ADDED PATCHY FOG OVERNIGHT FOR
THE FAR NORTHERN AREAS OF FORSYTH...GUILFORD AND PERSON COUNTIES.
SOUTH OF THE BOUNDARY...FAIRLY UNIFORM SOUTH-SOUTHWESTERLY LOW LEVEL
FLOW CONTINUES IN THE WARM SECTOR. THE 00Z KGSO AND KMHX RAOBS SHOW
ALL OF THE MOISTURE CONFINED BELOW 750MB WITH A WEAK CAP JUST
ABOVE. THE FEW SHOWERS THAT HAVE DEVELOPED THIS EVENING HAVE
STRUGGLED TO EXTEND ABOVE 11K FT AND HAVE NOT PRODUCED ANY LIGHTNING
DESPITE SOME WEAK CAPE JUST ABOVE THE CAP. FORCING ALOFT IS
DIFFICULT TO LOCATE IN THE MOIST SOUTHWESTERLY FLOW AHEAD OF THE
MAIN UPPER TROUGH...BUT REGIONAL SURFACE AND 850MB OBS SHOW A WEAK
WAVE NEAR SC/GA COASTAL AREAS. WHILE THIS WAVE IS FORECAST TO
WEAKEN FURTHER AS IT MOVES ALONG THE COAST...MOST OF THE FORECAST
MODELS SHOW A SLUG OF ISENTROPIC LIFT IN THE 295-305K LAYER MOVING
NORTH THROUGH THE COASTAL PLAIN AROUND 09Z. THE AVAILABLE CAMS SHOW
WHAT SHOULD BE SOME LOW TOPPED SHOWERS BRUSHING THE I-95
CORRIDOR...ESPECIALLY OVER THE NORTHERN COASTAL PLAIN. WILL HAVE A
30 POP IN THIS AREA AFTER 09Z...AND KEEP THE MENTION OF ISOLATED
SHOWERS ELSEWHERE.
TEMPS CURRENTLY IN THE UPPER 50S AND LOWER 60S WILL SHOULDN FALL
TOO MUCH MORE UNDER MOSTLY OVERCAST SKIES...SO WILL ONLY ADJUST LOWS
TO MATCH THE CURRENT TRENDS. LOWS 55-61. -BLS
MONDAY:
THERE IS GOOD AGREEMENT WITH THE TIMING OF THE COLD FRONT INTO
WESTERN NC LATE MONDAY AFTERNOON. THE LATE ARRIVAL OF THE SFC COLD
FRONT WILL KEEP THE ASSOCIATED MAIN BAND OF CONVECTION WEST OF THE
AREA UNTIL 21 TO 00Z. PRIOR TO THE ARRIVAL OF THIS BAND...ISOLATED
TO SCATTERED SHOWERS WILL BE POSSIBLE ACROSS CENTRAL NC WITHIN THE
40-50KT H8 LOW-LEVEL JET AND INCREASING RIGHT-ENTRANCE REGION
DYNAMICS. MODELS INDICATE ONLY MARGINAL INSTABILITY(200 TO 500
J/KG)...A LIKELY PRODUCT OF WIDESPREAD CLOUD COVER. GIVEN THE LACK
OF INSTABILITY AND THE SHORTWAVE DYNAMICS RACING OFF TO THE
NORTHEAST(GREAT LAKES)...EXPECT THUNDER TO BE AN EXCEPTION NOT THE
RULE. WILL PUT IN ISOLATED THUNDER IN THE FAR WESTERN ZONES ONLY.
TEMPERATURES WILL BE DEPENDENT ON CLOUD COVER AND PRECIP
COVERAGE...WITH HIGHS A TOUCH COOLER THAN PREVIOUSLY THOUGHT.
HIGHS IN THE UPPER 60S NW TO MID 70S SOUTHEAST WITH BREEZY SWLY
WINDS OF 15 T0 25 MPH.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM SUNDAY...
A COLD FRONT WILL APPROACH AND CROSS THE REGION OVERNIGHT MONDAY
INTO TUESDAY. PRECIP CHANCES WILL RAMP UP NEAR SUNSET ON MONDAY
ACROSS THE WEST AND THEN MOVE EASTWARD THROUGH THE OVERNIGHT HOURS
AND INTO EARLY TUESDAY. IT SHOULD BE NOTED THAT MODELS CONTINUE TO
TREND DRIER FOR CENTRAL NC WITH THE PASSAGE OF THIS COLD FRONT. IN
FACT...MODELS INDICATE A LINE OF SHOWERS ALONG AND AHEAD OF THE
FRONT MOVING INTO THE WESTERN PIEDMONT BY SUNSET...THEN WEAKENING
SIGNIFICANTLY AS IT MOVES EASTWARD INTO THE MORE STABLE AIR OVER THE
PIEDMONT/COASTAL PLAIN. AS A RESULT...WILL MAINTAIN LIKELY POPS FOR
LATE MONDAY/MONDAY EVENING IN THE WEST...WITH ONLY CHANCE POPS
FURTHER EAST TROUGH EARLY TUESDAY. PRECIP SHOULD COME TO AN END
TUESDAY AFTERNOON AS THE FRONT MOVES EAST OF THE AREA. INSTABILITY
APPEARS TO BE MARGINAL (AT BEST) AS THE FRONT CROSSES THE AREA
MONDAY NIGHT...BUT CANNOT COMPLETELY RULE OUT AN ISOLATED
THUNDERSTORM OR TWO.
TEMPS MONDAY NIGHT AND TUESDAY WILL ULTIMATELY BE DETERMINED BY THE
TIMING OF THE FRONT AND ASSOCIATED PRECIP AND EVENTUAL CAA. WITH THE
CURRENT TIMING OF THE FRONT IN MIND...WILL SHOW MILD TEMPS MONDAY
NIGHT...GENERALLY IN THE 50S. HIGHS ON TUESDAY ARE EXPECTED TO BE IN
THE MID/UPPER 50S ACROSS THE NORTHWEST (DUE TO THE EARLIER FRONTAL
PASSAGE) TO THE LOW/MID 60S FURTHER SOUTH AND EAST. THESE HIGHS MAY
VERY WELL OCCUR IN THE MORNING AND THEN FALL THROUGHOUT THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...
TUESDAY NIGHT THROUGH WEDNESDAY...THERE STILL IS QUITE A BIT OF
UNCERTAINTY WITH RESPECT TO THE WEATHER FOR THIS TIME FRAME. ALL THE
MODELS SHOW THE FRONT HANGING NEAR THE COAST WITH MULTIPLE LOW
PRESSURE WAVES TRACKING ALONG IT AND SPREADING PRECIP INTO EASTERN
NC...ALTHOUGH HOW FAR EAST IS IN QUESTION. ALL MODELS ALSO SHOW A
MID LEVEL WAVE TRACKING EASTWARD ACROSS THE AREA DURING THIS TIME
FRAME...ALTHOUGH TIMING/STRENGTH IS NOT WELL AGREED UPON. NOW THE
GFS IS STRONGER AND SLOWER (OPPOSITE OF 24 HOURS AGO) AND ACTUALLY
SPREADS PRECIP ACROSS THE ENTIRE FORECAST AREA LATE TUESDAY NIGHT
INTO WEDNESDAY. THE NAM SUPPORTS THIS SOLUTION SOMEWHAT...BUT THE
ECMWF AND CANADIAN KEEP MOST OF THE PRECIP ACROSS THE EASTERN
PORTIONS OF THE FORECAST AREA. FOR NOW...WILL MAINTAIN FORECAST
CONTINUITY AND SHOW A CHANCE OF RAIN IN THE EAST LATE TUESDAY NIGHT
AND WEDNESDAY...WITH ONLY A SLIGHT CHANCE FURTHER WEST. TEMPS WILL
LIKELY BE NEAR TO SLIGHTLY ABOVE NORMAL DURING THIS TIME FRAME.
THURSDAY THOUGH SUNDAY...CONDITIONS THEN LOOK TO IMPROVE FOR THE END
OF THE WORK WEEK AS SURFACE HIGH PRESSURE AND MID LEVEL RIDGING
BUILD INTO THE AREA. MODELS THEN SHOW THE NEXT SYSTEM APPROACHING
THE REGION OVER THE WEEKEND...WITH CLOUDS AND PRECIP CHANCES
POSSIBLY BEGINNING TO INCREASE LATE SATURDAY (ALTHOUGH TIMING THIS
FAR OUT IS ALWAYS IN QUESTION). TEMPS WILL SLOWLY MODERATE AT THE
END OF THE WEEK AND ESPECIALLY INTO THE WEEKEND AS THE SURFACE HIGH
MOVES OFFSHORE AND SOUTHERLY FLOW RETURNS TO THE AREA.
&&
.AVIATION /00Z SUNDAY THROUGH FRIDAY/...
AS OF 710 PM SUNDAY...
HIGH CONFIDENCE IN IFR/LIFR CIGS DEVELOPING LATER THIS EVENING AT
ALL CENTRAL NC FORECAST SITES. CIGS HAVE ALREADY DROPPED TO LIFR...
AND THESE CONDITIONS ARE LIKELY TO DOMINATE THROUGH THE NIGHT.
ELSEWHERE... MOIST AIR IN PLACE THROUGH THE LOWEST FEW THOUSAND FT
AND STEADY SW FLOW WILL FOSTER DEVELOPMENT OF LOW CIGS PRIOR TO 05Z.
FORECAST SOUNDINGS AND SREF PROBABILITIES SUPPORT CIGS BASED BELOW
500 FT AGL AT ALL LOCATIONS (HIGHEST CONFIDENCE AT RDU/RWI/FAY)
LASTING THROUGH SUNRISE MONDAY. VSBYS WILL BE MVFR TO IFR... WITH
STRATUS FAVORED OVER FOG... AND DO NOT EXPECT LONG-LIVED VSBYS UNDER
1 MILE (EXCEPT FOR TOWER VSBYS IN LOW CIGS). VSBYS WILL IMPROVE TO
VFR BY 13Z MONDAY BUT CIGS WILL BE SLOW TO RISE... LIKELY NOT
REACHING MVFR UNTIL AFTER 15Z... AND NOT TO VFR UNTIL AFTER 17Z. SW
WINDS (FROM 180-220 DEGREES) WILL STRENGTHEN TO 12-16 KTS
SUSTAINED... GUSTING TO 23-30 KTS FROM LATE MORNING THROUGH THE END
OF THE TAF VALID PERIOD.
LOOKING BEYOND 00Z TUESDAY... MVFR TO IFR CONDITIONS ARE EXPECTED TO
RETURN FROM MID EVENING THROUGH MONDAY NIGHT AS A COLD FRONT MOVES
IN FROM THE WEST. SHOWERS ARE LIKELY WITH THE FRONT AT INT/GSO WITH
A LESSER COVERAGE ELSEWHERE. A SHARP VEERING OF SW WINDS TO NW THEN
NORTH WILL OCCUR JUST BEHIND THE FRONTAL PASSAGE BETWEEN 05Z AND 12Z
TUESDAY MORNING... WITH A RETURN TO VFR CONDITIONS. MVFR CIGS ARE
LIKELY TO RETURN TUESDAY NIGHT THROUGH WEDNESDAY AS A COASTAL LOW
TRACKS UP ALONG THE CAROLINA COAST. VFR CONDITIONS ARE EXPECTED
WEDNESDAY NIGHT THROUGH FRIDAY WITH HIGH PRESSURE BUILDING OVER THE
REGION. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...CBL/BLS
SHORT TERM...KRR
LONG TERM....KRR
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
309 PM CST SAT DEC 8 2012
.SHORT TERM...
QUITE CHALLENGING TODAY. MODELS KEEP TRACKING LOW A BIT FARTHER
SOUTH EACH RUN AND 12Z GFS AND LATEST RAP MODEL GO ALONG WITH 00Z
AND 12Z EURO IN HAVING LOW JUST NORTH OR NORTHEAST OF SIOUX FALLS
AT 12Z SUN. TRACK OF MID LEVEL LOW WOULD BRING HEAVIEST SNOW INTO
MOSTLY NORTHERN INTO NORTHEAST AND EAST CENTRAL SOUTH DAKOTA
TOWARD PERHAPS ST CLOUD AND THE NRN TWIN CITIES METRO AREA
OVERNIGHT INTO SUNDAY. THUS HEAVIEST SNOW NOW JUST CLIPS THE FAR
SOUTH FCST AREA IN WARNING AREA. FARTHER SOUTH TRACK GIVES A BIT
MORE CONFIDENCE NOW TO LEAVING STRETCH FROM VALLEY CITY TO FARGO
TO PARK RAPIDS IN ADVISORY FOR UP TO 4 INCHES WITH LESS FARTHER
NORTH.
NOW WILL ADD A FEW COUNTIES IN THE FAR NORTH ALONG ND/MB
BORDER TO WINTER WX ADVISORY TONIGHT AS AREA THERE RECEIVED 4
INCHES OF FLUFF ACCORDING TO SPOTTERS AND WILL EASILY BLOW AROUND
TONIGHT AS WINDS UP THERE INCREASE TO AROUND 20 MPH. PLUS WIND
CHILLS WILL DROP TO BELOW -25F LATER TONIGHT.
925 MB WINDS FARTHER SOUTH WILL INCREASE GREATLY 06Z TO 09Z FROM
NEAR GRAND FORKS SOUTH INTO ERN SD WITH 40-45 KTS THERE AND DUE TO
PRESSURE GRADIENT AND COLD ADVECTION SHOULD SEE GUSTS OVER 30 KTS
ESP IN SE ND IN THAT 09Z TO 18Z PERIOD. WINDS WILL HIT AFTER THE
MAIN SNOW AND WITH MAIN SNOW BEING LESS IN ALL BUT FAR SOUTH THAN
EARLIER THINKING STILL THINK ADV OK RIGHT NOW. COULD SEE BLIZZARD
CONDITIONS DEVELOP HOWEVER BUT QUITE IFFY ON THIS...MORE OF AN
OPEN COUNTRY THING VS IN TOWN AS MAIN SNOWFALL ITSELF IS JUST A
BIT SOUTH. EVE SHIFT CAN MONITOR.
SYSTEM WILL MOVE EAST SUNDAY AND SNOW AND WIND WILL
DIMINISH...SNOW FIRST THEN WIND. VERY COLD WITH 12Z-18Z WIND
CHILLS TO -30 IN THE FAR NORTHWEST FCST AREA. WILL LET MID SHIFT
ISSUE ANY WC HEADLINES. DIDNT WANT TO EXTEND WINTER WX HEADLINES
PAST 12Z SUN UP IN THE FAR NORTHWEST AS WINDS WILL DIMINISH THERE
FIRST.
HIGH PRESSURE WILL MOVE IN SUN NIGHT AND SOME SPOTS WILL GET INTO
THE NEGATIVE TEENS. CLOUDS WILL MOVE IN LATE SUN NIGHT INTO MONDAY
AND TUESDAY AS SEVERAL SHORT WAVES MOVE THROUGH BUT DOES LOOK
MAINLY DRY. COULD BE A FEW SPITS OF -SN BUT DID NOT MENTION YET.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
12 UTC GFS/ECMWF IN REASONABLE AGREEMENT NEXT WEEK...BOTH SHOWING
NORTHWEST FLOW ALOFT SHIFTING TO THE WEST/SOUTHWEST THROUGH THE
PERIOD. BEST CHANCE FOR SNOW WILL BE ALONG AND NORTH OF THE HIGHWAY
2 CORRIDOR ON WEDNESDAY AS A WEAK SHORT-WAVE MOVES ACROSS SOUTHERN
CANADA. THURSDAY INTO EARLY NEXT WEEKEND LOOK MAINLY DRY AS MAJORITY
OF ENERGY ALOFT GETS SHUNTED TO THE SOUTH WITH FOUR CORNERS TROUGH.
THIS FEATURE EJECTS NORTHEASTWARD AND INTO SOUTHEAST MN/WEST CENTRAL
WI BY SATURDAY...SO WILL NEED TO WATCH FOR ANY NORTHWARD OR WESTWARD
SHIFTS...REQUIRING AN INCREASE IN THE CURRENT ALL BLEND 20 POPS.
TEMPERATURES WILL BE SEASONABLE ON WEDNESDAY WITH HIGHS IN THE 20S
BEFORE A COOL-DOWN FOR THE LATTER HALF OF THE WEEK AFTER A COLD
FRONT MOVES THROUGH WEDNESDAY NIGHT. HIGHS THURSDAY/FRIDAY WILL
RANGE FROM THE SINGLE DIGITS ABOVE ZERO TO THE UPPER TEENS TO NEAR
20 DEGREES.
&&
.AVIATION...
MVFR/IFR CEILINGS WILL CONTINUE THIS EVENING AND OVERNIGHT...WITH
INCREASING SNOW CHANCES FROM WEST TO EAST AS A STRONG LOW PRESSURE
SYSTEM TRACKS ACROSS SD INTO WEST CENTRAL MN. EXPECT REDUCTIONS IN
VISIBILITY AS LOW AS 1/4 SM FROM SNOW AND WIND...ESPECIALLY BY 12
UTC SUNDAY AT VALLEY AIRFIELDS. WINDS WILL SHIFT TO THE NORTH
BETWEEN 00 AND 06 UTC THIS EVENING AND GUST TO 30 KTS OR MORE BY
SUNDAY MORNING. ATTEMPTED TO SIMPLIFY 18 UTC TAFS AS MUCH AS
POSSIBLE...BUT AMENDMENTS WILL BE NECESSARY. EXPECT SLOWLY
IMPROVING CONDITIONS LATE IN THE PERIOD FROM NORTHWEST TO
SOUTHEAST.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR NDZ024-026>030-038-039.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR NDZ049-052-053.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR NDZ006>008-014>016-054.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR MNZ001>003-013>017-022>024-027-028.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR MNZ029>032-040.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR MNZ004-007.
&&
$$
RIDDLE/ROGERS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
947 PM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST OVERNIGHT WHICH WILL DRAG A COLD
FRONT ACROSS THE REGION LATE TONIGHT AND EARLY MONDAY MORNING.
HIGH PRESSURE BUILDING INTO THE CENTRAL PART OF THE COUNTRY WILL
HELP USHER IN DRIER AND COLDER AIR BEHIND THIS FRONT.
&&
.NEAR TERM /THROUGH MONDAY/...
SHOWERS HAVE BEEN FILLING IN AS THEY MOVE INTO THE FORECAST AREA
THIS EVENING AHEAD OF AN APPROACHING LOW AND COLD FRONT. ISOLATED
TO SCATTERED EMBEDDED THUNDERSTORMS HAVE ALSO BEEN OCCURRING WITH
THE BETTER COVERAGE IN THE SOUTHWEST COUNTIES. WILL CONTINUE TO
SEE SHOWERS AND THUNDERSTORMS PUSH ACROSS THE REGION OVERNIGHT.
EXPECT MUCH OF THIS ACTIVITY TO DIMINISH CONSIDERABLY AS THE COLD
FRONT MOVES INTO THE AREA LATER TONIGHT.
COLD FRONT WILL BISECT THE REGION AT DAYBREAK AND CONTINUE THROUGH
THE REST OF THE FORECAST AREA EARLY IN THE MORNING. TEMPERATURES
WILL REMAIN QUITE MILD UNTIL FRONTAL PASSAGE WITH READINGS FALLING
THEREAFTER. APPEARS THAT MANY LOCATIONS WILL HAVE A 12Z HIGH AND A
13Z LOW.
12Z HIGH RESOLUTION NAM-ARW HAD SHOWN A SECONDARY WAVE OF
PRECIPITATION BEHIND THE COLD FRONT SPREADING NORTHEAST IN THE
MORNING. PAST FEW RUNS OF THE RAP HAVE LEANED TOWARDS THIS AND 00Z
NAM SHOWS IT TO SOME EXTENT. SO HAVE INCREASED POPS AGAIN DURING
THE MORNING MAINLY SOUTH AND EAST OF I-71. THIS WILL ALL PUSH OFF
TO THE EAST DURING THE AFTERNOON. PRECIPITATION SHOULD ALL BE RAIN
AS COOL DOWN WILL BE GRADUAL AFTER INITIAL SURGE WITH THE FRONT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
A FEW LINGERING CLOUDS AND THE COLD PUSH DOWNWIND OF LAKE
MICHIGAN COULD SPARK SOME FLURRIES OR A LIGHT SNOW SHOWER EARLY
MONDAY EVENING WITH LITTLE IF ANY NEGATIVE IMPACTS TO THE REGION.
SKIES WILL REMAIN GENERALLY CLOUDY UNTIL LATE TUESDAY WHEN
RELATIVELY WARMER AIR ALOFT IS FOUND ON THE BACK SIDE OF THE
DEPARTING RIDGE OF H8 HIGH PRESSURE. A SURFACE RIDGE OF HIGH
PRESSURE WILL ALSO BECOME MORE ESTABLISHED OVER THE AREA AT THIS
TIME. TEMPERATURES THROUGH THIS TIME WILL BE COLDER BUT VERY NEAR
CLIMATOLOGICAL NORMALS FOR THIS TIME OF YEAR.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
SPRAWLING HIGH PRESSURE WILL BE RUNNING FROM NEW ENGLAND BACK INTO
THE OHIO VALLEY AT THE BEGINNING OF THE PERIOD. THE HIGH WILL
CONTROL THE REGIONS WEATHER INTO FRIDAY.
MODELS HAVE DIVERGED SOME WITH THEIR SOLUTION FOR THE SYSTEM THAT
KICKS OUT OF THE PLAINS FRIDAY INTO SATURDAY. THE GFS IS MUCH WEAKER
AND QUICKER WITH THE SYSTEM AND THEREFORE PUSHES A CDFNT ACROSS THE
FA SATURDAY...WITH COOLER AND DRIER AIR WORKING IN FOR SUNDAY. THE
ECMWF...DGEX AND TO SOME EXTENT THE CMC ARE SLOWER AND DEEPER. THIS
DELAYS THE START OF THE PCPN BY ABOUT 6 HOURS...BUT ALSO DELAYS
FROPA UNTIL SUNDAY. THE GFS LOOKS LIKE THE OUTLIER...SO LEANED
TOWARDS THE CONSENSUS SOLUTION. SO KEPT HIGHER POPS SATURDAY NIGHT
INTO SUNDAY AND WENT WARMER OVERNIGHT LOWS SATURDAY NIGHT.
WITH HIGH OVER THE REGION ON WEDNESDAY INTO FRIDAY...THERE SHOULD BE
PLENTY OF SUNSHINE. COULD SEE SOME PERIODS OF AC OR CI AS WEAK S/W
WORKS THROUGH THE H5 FLOW.
A GRADUAL WARMING WILL OCCUR DURING THE LATER HALF OF THE WEEK. ON
WEDNESDAY...HIGHS ARE EXPECTED TO PUSH INTO THE LOWER TO MID 40S.
HIGHS WILL PUSH INTO THE UPPER 40S TO LOWER 50S BY THE END OF THE
WEEK AND OVER THE WEEKEND.
ANOTHER COOL NIGHT IS EXPECTED WEDNESDAY NIGHT WITH TEMPERATURES
FALLING BACK INTO THE 20S BEFORE THE WARMER AIR BEGINS TO WORK IN
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
SHOWERS WILL CONTINUE TO MOVE ACROSS THE AREA THROUGH MUCH OF THE
NIGHT. APPEARS HEAVIER ACTIVITY MAY BE PRIMARILY LIMITED TO THE
CINCINNATI TERMINALS ALTHOUGH THUNDER MAY STAY JUST SOUTH OF
THERE. THERE ARE SOME BREAKS IN THE LOWER CLOUDS ACROSS THE REGION
AT ISSUANCE TIME. BUT EXPECT THESE TO BE SHORT-LIVED. CEILINGS
WILL GENERALLY BE MVFR TO IFR WITH ALL LOCATIONS FALLING TO IFR OR
EVEN LIFR LATER IN THE NIGHT. VISIBILITY RESTRICTIONS BEYOND MVFR
WILL PROBABLY BE LIMITED TO TIMES OF HEAVIER RAINFALL.
A COLD FRONT WILL MOVE THROUGH THE REGION BETWEEN 08Z AND 12Z.
SHOULD ONLY BE SLIGHT IMPROVEMENTS IN CEILING AND VISIBILITY
IMMEDIATELY AFTER THIS PASSES. THERE WILL STILL BE SOME SHOWERS
OCCURRING BEHIND THE FRONT WELL INTO THE MORNING. THEREAFTER
CEILINGS SHOULD LIFT TO MVFR AND VISIBILITIES BECOMING
UNRESTRICTED.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE MONDAY NIGHT
INTO TUESDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
703 PM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE REGION TONIGHT PULLING A
TRAILING COLD FRONT THROUGH THE AREA. HIGH PRESSURE WILL MOVE EAST
UP THE OHIO VALLEY MONDAY NIGHT AND TUESDAY BRIEFLY STALLING OVER
WEST VIRGINIA WEDNESDAY INTO THURSDAY BEFORE CONTINUING EAST FRIDAY.
ANOTHER LOW SHOULD MOVE NORTHEAST FROM THE PLAINS THROUGH THE GREAT
LAKES NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AN AREA OF SHOWERS CONTINUE TO MOVE NORTHEAST IN ASSOCIATION WITH
A VORTICITY COUPLET. POSITIVE VORTICITY MAXIMUM IS JUST SOUTH OF
THE WARM FRONT AND THIS IS WHERE THE BEST SUPPORT FOR THE SHOWERS
IS CURRENTLY LOCATED. I AMENDED THE GRIDS TO ACCOUNT FOR THIS
ACTIVITY MOVING NORTHEAST THROUGH THE SOUTHEASTERN TWO THIRDS OF
THE FORECAST AREA. UP IN THE NORTHWEST...NEGATIVE VORTICITY
ADVECTION WAS PREVENTING SHOWERS FROM DEVELOP ALONG WITH THIS AREA
BEING JUST NORTH OR UNDER THE WARM FRONTAL BOUNDARY.
LATEST RUC MODEL SHOWS A LARGER SURGE OF UPWARD VERTICAL MOTION IN
ASSOCIATION WITH THE NEXT VORTICITY MAXIMUM WILL SURGE NORTHEAST
INTO THE REGION LATER TONIGHT AND MAINLY AFTER MIDNIGHT. I THINK
THE NORTHWEST SHOULD REMAIN FOR THE MOST PART DRY WITH THE
EXCEPTION OF A FEW SPRINKLES OR SOME VERY LIGHT DRIZZLE.
TEMPERATURES WILL TREND UPWARD OVER THE SOUTHEAST PORTION OF THE
FORECAST AREA AND ENOUGH INSTABILITY WILL BE PRESENT TO SUPPORT
POSSIBILITY FOR A FEW RUMBLES OF THUNDER.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
COLDER AND DRIER AIR WILL SPREAD SE ACROSS THE CWA BEHIND THE COLD
FRONT MONDAY. TEMPS WILL PROBABLY FALL SLOWLY THROUGHOUT THE DAY FOR
MOST OF THE AREA.
RAIN WILL GRADUALLY CHANGE TO SNOW NW TO SE MON INTO MON EVE BUT THE
SIGNIFICANT PRECIP WILL ALSO BE TAPERING OFF SO NOT LOOKING FOR MUCH
IF ANY ACCUMULATION MON.
ADDED LAKE EFFECT SHSN FOR MON NIGHT INTO TUE WILL PRODUCE
ACCUMULATION. THE MODELS HAVE TRENDED TO HAVING MORE MID LEVEL
MOISTURE PRESENT MON NIGHT SO NOW THINK SOME OF THE FAVORED SNOWBELT
HIGHER TERRAIN AREAS COULD SEE 1 TO LOCALLY 3 INCHES OF SNOW BY THE
TIME THE SHSN TAPERS TO FLURRIES AROUND MIDDAY TUE.
HIGH PRESSURE RIDGES UP THE OH VALLEY LATE TUE AND SHOULD LEAD TO
DRY CONDITIONS FOR TUE NIGHT INTO WED FOR MOST OF THE AREA. THE
QUESTION IS WHETHER WARM ADVECTION LIFT AND FORCING FROM A WEAK
UPPER TROUGH COULD LEAD TO SOME LIGHT SNOW TO OCCUR NEAR LERI LATE
TUE NIGHT AND WED. GENERAL CONSENSUS IS TO STAY WITH A DRY FORECAST
FOR NOW.
WARM ADVECTION CONTINUES THRU WED NIGHT. HIGHS WED AFTN SHOULD
REBOUND INTO THE UPPER 30S NE TO LOWER 40S SW. THE MODELS SHOW MORE
MID AND UPPER LEVEL RIDGING BY WED NIGHT HELPING TO PUSH THE FIELD
OF MOISTURE NEAR LAKE ERIE EARLIER IN THE DAY FURTHER NORTH TO
LESSEN ANY THREAT FOR PRECIP.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE LONG TERM PERIOD WILL START OUT QUIET WITH A RIDGE OF HIGH
PRESSURE JUST TO THE SOUTHEAST OF THE AREA. THIS RIDGE WILL
MAINTAIN SW FLOW OVER THE LOCAL AREA RESULTING IN FAIR WEATHER AND
TEMPS A LITTLE ABOVE NORMAL. A STORM SYSTEM WILL AFFECT THE REGION
NEXT WEEKEND BUT ALL OF THE NEW GUIDANCE INCLUDING THE 12Z ECMWF HAS
SLOWED THIS SYSTEM DOWN. IT NOW APPEARS THAT IT WILL BE SATURDAY
BEFORE ANY PRECIP REACHES THE WESTERN END OF THE AREA. WILL GO WITH
CHANCE POPS FOR SATURDAY THROUGH SUNDAY BUT IF THE MODELS ARE EVEN
CLOSE TO BEING CORRECT WILL EVENTUALLY NEED CATEGORICAL CHANCES.
HIGHS BOTH SATURDAY AND SUNDAY WILL CONTINUE IN THE MIDDLE 40S.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
RAIN AND LOW CLOUDS WILL CONTINUE TO SPREAD NORTH ACROSS THE AREA
WITH A SURGE OF WARM ADVECTION. AS THE SOUTH WINDS BECOME
ESTABLISHED IN THE WARM SECTOR...IFR CONDITIONS COULD BOUNCE
AROUND OCCASIONALLY IMPROVING TO MVFR... ESPECIALLY AT THE
DOWN SLOPE SITES SUCH AS KCLE AND KERI. THE COLD FRONT WILL PUSH
ACROSS THE AREA FROM WEST TO EAST...CROSSING NORTHWEST OHIO DURING
THE PREDAWN HOURS AND NE OH/NW PA EARLY MONDAY MORNING. CEILINGS
COULD DROP EVEN LOWER...LIFR FOR A WHILE MONDAY MORNING... THEN
SLOWLY IMPROVE FROM WEST TO EAST ON MONDAY MIDDAY AND AFTERNOON
BUT IMPROVING ONLY TO MVFR. VISIBILITIES SHOULD IMPROVE AS
SLIGHTLY DRIER AND COLDER AIR SPREADS IN. SNOW SHOWERS ARE
POSSIBLE MONDAY AFTERNOON...MAINLY ACROSS NE OH/NW PA.
OUTLOOK...NON-VFR LIKELY ACROSS NE OH/NW PA MONDAY NIGHT INTO
TUESDAY...OTHERWISE VFR.
&&
.MARINE...
EASTERLY WINDS CONTINUE ON THE LAKE AND HAVE EXTENDED THE SMALL
CRAFT ON THE WEST END FOR A FEW HOURS. THE FLOW SHOULD BECOME S
THEN SW OVERNIGHT AS LOW PRESSURE PASSES TO THE NORTH OF LAKE ERIE
AND MOVES TO LAKE ONTARIO. THE FLOW WILL BECOME NW ON MONDAY WITH
SPEEDS INCREASING AND WILL LIKELY NEED ANOTHER SMALL CRAFT.
DIMINISHING NW FLOW IS EXPECTED MONDAY NIGHT WITH THE FLOW BECOMING
SW ON TUESDAY AS HIGH PRESSURE SLIDES EAST ACROSS THE REGION. A
RIDGE WILL THEN REMAIN JUST EAST OF THE LAKE THROUGH THE END OF THE
PERIOD. THIS WILL MAINTAIN THE SW FLOW THROUGH FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR
LEZ142>144.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...KUBINA
AVIATION...KOSARIK
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
330 PM EST SAT DEC 8 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH AND ITS ASSOCIATED SURFACE LOW WILL TRACK
NORTHEAST ACROSS THE EASTERN GREAT LAKES AND ST. LAWRENCE RIVER
VALLEY INTO TONIGHT. A COLD FRONT TRAILING THE LOW WILL PUSH
SLOWLY SOUTHEAST THROUGH THE REGION AND STALL OUT NEAR THE MASON-
DIXON LINE LATE TONIGHT AND EARLY SUNDAY...AS AN AREA OF HIGH
PRESSURE BUILDS INTO SOUTHEASTERN CANADA AND NORTHERN NEW ENGLAND.
THE FRONTAL ZONE WILL RETURN BACK TO THE NORTH AS A WARM FRONT
LATER SUNDAY INTO SUNDAY NIGHT...AS A MATURE CYCLONE DEVELOPS OVER
THE MIDWEST AND TRACKS NORTHEAST THROUGH THE GREAT LAKES. THIS
SYSTEM WILL BRING A STRONGER COLD FRONT THROUGH THE REGION ON
MONDAY.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
LATEST RUC DATA SHOWS THE WEAK ~1010MB SFC LOW OVR LK ONTARIO AS
OF 18Z. A COLD FRONT TRAILING THE LOW EXTENDS SWWD ACRS LK ERIE
AND N/CNTRL OH. AS THE LOW CONTINUES TO LIFT NEWD THRU THE REST
OF TODAY...EXPECT THE COLD FRONT TO MAKE SLOW SEWD PROGRESS INTO
THE NW MTNS BY 00Z.
LOW STRATUS AND FOG HAS BEEN REMARKABLY PERSISTENT OVR THE MID-
LWR SUSQ VLY...WITH THE LATEST 18Z OBS JUST NOW SHOWING SOME
SLIGHT IMPROVEMENT. THE LOW DECEMBER SUN ANGLE AND LGT/VRB WINDS
HAVE LIMITED MIXING PROCESSES THUS FAR...HOWEVER CONSENSUS OF THE
HIGH RES DATA STILL SUPPORTS A LATE AFTN BREAK-OUT INTO THE WARM
AIR /ESPECIALLY OVR THE LWR SUSQ VLY NEAR THE MD LINE/ WHICH
SHOULD ALLOW TEMPS TO QUICKLY SURGE INTO THE LOW 50S. AS EXPECTED
THE MILD AIR HAS REACHED THE CNTRL MTNS WITH AOO AND UNV IN THE
50S.
THE ALLEGHENIES WILL BE MOST SUSCEPTIBLE TO SHOWERS INTO THE
EVE...GIVEN WEAK UPSLOPE WITHIN CHANNEL OF DEEP MSTR/ABOVE NORMAL
PWATS LYING OVER THE REGION. SHORTWAVES MOVG QUICKLY NEWD IN THE
BROAD SWLY FLOW ALOFT WILL ALSO SUPPORT POCKETS OF ISENT LIFT
WHICH WILL CONTINUE TO PROMOTE SHOWER ACTIVITY IN LLVL CNVGNC ZONE
ALONG/AHEAD OF THE APPROACHING FNTL BNDRY. DESPITE THE HIGH MSTR
AVAILABILITY...QPF AMTS WILL REMAIN BE ON THE LGT SIDE.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE FRONTAL ZONE WILL SHIFT SEWD ACRS CENTRAL PA EARLY TONIGHT
AND BECOME QUASI-STNRY NEAR THE PA/MD BORDER BY EARLY SUNDAY.
SFC RIDGE AXIS EXTENDING SEWD FROM 1030MB HIGH OVR ONTARIO WILL
MOVE THRU NRN AREAS LATE TNT INTO EARLY SUNDAY...SUPPRESSING THE
CHC FOR RAIN TO THE FAR SRN TIER NEAR THE STALLED WAVY FNTL ZONE.
VEERING LLVL WINDS AND INC WAA SHOULD SUPPORT INCREASING POPS OVR
THE SRN TIER BY THE END OF THE SHORT TERM PERIOD. A NWLY FLOW
BEHIND THE FRONT WILL DIRECT COLDER AIR INTO NRN SXNS WITH TEMPS
FALLING NR THE FZG MARK BY DAYBREAK SUNDAY.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY MAY DAWN PTSUNNY ACROSS NORTHERN PA...BUT THAT WILL BE
SHORT-LIVED...AS FRONTAL ZONE SHIFTS NORTH. RAIN/DZ WILL BE ON THE
INCREASE FROM SW TO NE ONCE AGAIN DURING SUNDAY AS WARM AIR
ADVECTION BEGINS TO INCREASE WITH THE APPROACH OF THE NEXT
SHORTWAVE AND WARM FRONT LIFTING BACK TO THE NORTH. MDL DATA
SHOWING THE BEST FGEN FORCING LIFTING ACROSS THE SOUTHERN COUNTIES
BTWN 12Z-20Z...SO WILL PLACE HIGHEST POPS OF ARND 80 PCT IN THIS
AREA. ENSEMBLE MEAN QPF NOT VERY IMPRESSIVE SUNDAY...RANGING FROM
ARND A QUARTER INCH IN THE SOUTH...TO JUST A FEW HUNDREDTHS NORTH.
WITH THE HIGH RETREATING OFF TO OUR NE...LI PROGS SHOW A STRONG
COLD AIR DAMMING SIGNATURE SUPPORTING A CHILLY DAY WITH HIGHS ONLY
IN THE 40S. SOME THE THE HIGHER TERRAIN ACROSS CENTRAL PA MAY TOP
OUT IN THE U30S. WHILE THIS WILL BE COOLER THAN TODAY...IT WILL
STILL BE A BIT ABOVE NORMAL FOR THE SECOND WEEK OF DECEMBER.
MOST OF CENTRAL PA WILL BRIEFLY BREAK INTO THE WARM SECTOR ON
MONDAY...AS SFC LOW TRACKS NORTH OF THE STATE...PUSHING TEMPS WELL
ABV SEASONAL NORMS ONCE AGAIN. THE TRAILING COLD FRONT WILL SAG SE
THRU THE REGION ON MONDAY WITH AN AREA OF RAIN FALLING BEHIND
FRONT DUE TO AGEO THERMALLY DIRECT CIRCULATION ASSOC WITH JET
STREAK OVR THE EASTERN GRT LKS. ENS MEAN QPF MONDAY RANGES FROM 0.50
TO 0.75 INCHES OVER MUCH OF CENTRAL PA.
ENOUGH COLD AIR COULD ARRIVE BEHIND CD FRONT FOR A BRIEF CHANGE TO
SHSN MON NIGHT. HOWEVER...ANY ACCUMS WOULD LIKELY BE VERY LGT.
ALL MED RANGE GUIDANCE INDICATING SFC ANTICYCLONE BUILDS ACROSS
THE MID ATLANTIC AREA TUE-FRI...SUPPORTING A HIGH CONFIDENCE FCST
OF FAIR WX FOR THE REST OF THE WORK WEEK. GEFS MEAN 925TEMPS
SUPPORT HIGHS A BIT ABV NORMAL...WHILE CLEAR SKIES AND LGT WINDS
UNDER SFC HIGH SHOULD ALLOW NIGHT-TIME TEMPS TO FALL TO NEAR
NORMAL READINGS.
BUILDING MDL CONSENSUS ON ANOTHER LOW TRACKING TO OUR WEST OVR THE
WEEKEND. WILL INTRODUCE MENTION OF PRECIP FRI NITE AND SAT. COULD
BE ENOUGH LL COLD AIR FOR A BIT OF FZRA TO START BEFORE EVENTUAL
CHANGE TO RAIN.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
08/18Z - 09/18Z...
TROUBLE SPOT THIS AFTN REMAINS THE ERN TERMINALS WITH IFR/LIFR
CONDS SLOW TO IMPROVE. ALTHOUGH THE GUIDANCE HAS GENERALLY BEEN
TOO OPTIMISTIC...RECENT OBSERVATIONAL TRENDS ALONG WITH VIS SATL
DATA ARE SUPPORTING A GRADUAL IMPROVEMENT TO MVFR BY THIS EVE.
TO THE WEST...ANTICIPATE MVFR CONDS AT BFD AND JST TO GO BACK DOWN
TO IFR AS LOWER CIGS AND ONCL -SHRA MOVE INTO THE AREA AHEAD OF
COLD FRONT PRESSING SEWD FROM LK ERIE. UNV/AOO ENJOYING BRIEF VFR
BUT SHOULD TREND TO MVFR BASED ON UPSTREAM CIGS.
CONFIDENCE IN THE 18Z TAF PACKAGE IS SLIGHTLY BELOW AVG GIVEN THE
COMPLEX SFC PATTERN EVOLVING OVR CNTRL PA. FCST FOR LATE TNT INTO
EARLY SUNDAY LEANS TWD THE PESSIMISTIC SIDE OF THE GUIDANCE. THE
PATTERN FOR SUNDAY SUGGESTS A PROLONGED PERIOD OF LOW CIGS AND
VISBY WITH PERIODS OF -RA.
OUTLOOK...
SUN...MVFR/IFR WITH PDS OF RAIN.
MON...STG FROPA/WSHFT. MVFR/IFR BCMG MVFR/VFR CNTRL/EAST.
RAIN...POSS ENDING AS SNOW IN THE WEST.
MON NGT-TUE...MVFR WEST TO VFR EAST.
TUE-THUR...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...FITZGERALD
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
145 PM EST SAT DEC 8 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH AND ITS ASSOCIATED SURFACE LOW WILL TRACK
NORTHEAST ACROSS THE EASTERN GREAT LAKES AND ST. LAWRENCE RIVER
VALLEY INTO TONIGHT. A COLD FRONT TRAILING THE LOW WILL PUSH
SLOWLY SOUTHEAST THROUGH THE REGION AND STALL OUT NEAR THE MASON-
DIXON LINE LATE TONIGHT AND EARLY SUNDAY...AS AN AREA OF HIGH
PRESSURE BUILDS INTO SOUTHEASTERN CANADA AND NORTHERN NEW ENGLAND.
THE FRONTAL ZONE WILL RETURN BACK TO THE NORTH AS A WARM FRONT
LATER SUNDAY INTO SUNDAY NIGHT...AS A MATURE CYCLONE DEVELOPS OVER
THE MIDWEST AND TRACKS NORTHEAST THROUGH THE GREAT LAKES. THIS
SYSTEM WILL BRING A STRONGER COLD FRONT THROUGH THE REGION ON
MONDAY.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
LATEST RUC DATA SHOWS THE WEAK ~1010MB SFC LOW OVR LK ONTARIO AS
OF 18Z. A COLD FRONT TRAILING THE LOW EXTENDS SWWD ACRS LK ERIE
AND N/CNTRL OH. AS THE LOW CONTINUES TO LIFT NEWD THRU THE REST
OF TODAY...EXPECT THE COLD FRONT TO MAKE SLOW SEWD PROGRESS INTO
THE NW MTNS BY 00Z.
LOW STRATUS AND FOG HAS BEEN REMARKABLY PERSISTENT OVR THE MID-
LWR SUSQ VLY...WITH THE LATEST 18Z OBS JUST NOW SHOWING SOME
SLIGHT IMPROVEMENT. THE LOW DECEMBER SUN ANGLE AND LGT/VRB WINDS
HAVE LIMITED MIXING PROCESSES THUS FAR...HOWEVER CONSENSUS OF THE
HIGH RES DATA STILL SUPPORTS A LATE AFTN BREAK-OUT INTO THE WARM
AIR /ESPECIALLY OVR THE LWR SUSQ VLY NEAR THE MD LINE/ WHICH
SHOULD ALLOW TEMPS TO QUICKLY SURGE INTO THE LOW 50S. AS EXPECTED
THE MILD AIR HAS REACHED THE CNTRL MTNS WITH AOO AND UNV IN THE
50S.
THE ALLEGHENIES WILL BE MOST SUSCEPTIBLE TO SHOWERS INTO THE
EVE...GIVEN WEAK UPSLOPE WITHIN CHANNEL OF DEEP MSTR/ABOVE NORMAL
PWATS LYING OVER THE REGION. SHORTWAVES MOVG QUICKLY NEWD IN THE
BROAD SWLY FLOW ALOFT WILL ALSO SUPPORT POCKETS OF ISENT LIFT
WHICH WILL CONTINUE TO PROMOTE SHOWER ACTIVITY IN LLVL CNVGNC ZONE
ALONG/AHEAD OF THE APPROACHING FNTL BNDRY. DESPITE THE HIGH MSTR
AVAILABILITY...QPF AMTS WILL REMAIN BE ON THE LGT SIDE.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE FRONTAL ZONE WILL SHIFT SEWD ACRS CENTRAL PA EARLY TONIGHT
AND BECOME QUASI-STNRY NEAR THE PA/MD BORDER BY EARLY SUNDAY.
SFC RIDGE AXIS EXTENDING SEWD FROM 1030MB HIGH OVR ONTARIO WILL
MOVE THRU NRN AREAS LATE TNT INTO EARLY SUNDAY...SUPPRESSING THE
CHC FOR RAIN TO THE FAR SRN TIER NEAR THE STALLED WAVY FNTL ZONE.
VEERING LLVL WINDS AND INC WAA SHOULD SUPPORT INCREASING POPS OVR
THE SRN TIER BY THE END OF THE SHORT TERM PERIOD. A NWLY FLOW
BEHIND THE FRONT WILL DIRECT COLDER AIR INTO NRN SXNS WITH TEMPS
FALLING NR THE FZG MARK BY DAYBREAK SUNDAY.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
SHOWERS WILL BE ON THE INCREASE FROM SW TO NE ONCE AGAIN BY THE
LATTER HALF OF SUNDAY AS WARM AIR ADVECTION BEGINS TO INCREASE
WITH THE APPROACH OF THE NEXT SHORTWAVE AND WARM FRONT LIFTING
BACK TO THE NORTH. SREF SHOWS PWATS SURGING TO 2-3 STD DEV ABOVE
NORMAL INTO THE OHIO VALLEY AND WESTERN PA BY LATE SUNDAY...ALL
AIMED AT THE LOCAL AREA.
WITH THE HIGH RETREATING OFF TO OUR NE...LI PROGS SHOW A STRONG
COLD AIR DAMMING SIGNATURE SUPPORTING A CHILLY DAY WITH HIGHS ONLY
IN THE 40S. WHILE THIS WILL BE COOLER THAN TODAY...IT WILL STILL
AVERAGE SEVERAL DEG ABOVE NORMAL FOR THE SECOND WEEK OF DECEMBER.
THE WAVY COLD FRONT WILL MOVE THROUGH THE AREA MONDAY WITH ANOTHER
WIDESPREAD SOAKING RAIN SLATED FOR THE AREA. MODELS ARE IN
REMARKABLE AGREEMENT ON TIMING...SUPPORTING A HIGH CONFIDENCE IN
THE IDEA OF VERY HIGH POPS FOR WHAT IS REALLY A DAY 3 FORECAST.
THE FRONT IS FCST TO BE EITHER OVER OR JUST EAST OF THE LOWER SUSQ
BY MONDAY EVENING...BRINGING A HALT TO THE STEADY RAIN. COLD AIR
WILL BE STACKED VERY CLOSE BEHIND THE FRONT WHICH COULD LEAD TO A
BRIEF CHANGEOVER TO SNOW...BUT LATEST INDICATIONS ARE FOR LITTLE
OR NO SNOW ACCUMS BEHIND THE SYSTEM.
SHORTWAVE RIDGING ALOFT ALLOWS FOR HIGH PRESSURE TO RAPIDLY FILL
IN BEHIND THE DEPARTING FRONTAL SYSTEM TUES-WED...BRINGING A
PROLONGED PERIOD OF DRY WEATHER...FOLLOWED BY A GRADUAL WARM UP AS
OUR FLOW EVENTUALLY TURNS WSW ALLOWING FOR A MODERATION IN TEMPS
BY THE END OF THE WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
08/18Z - 09/18Z...
TROUBLE SPOT THIS AFTN REMAINS THE ERN TERMINALS WITH IFR/LIFR
CONDS SLOW TO IMPROVE. ALTHOUGH THE GUIDANCE HAS GENERALLY BEEN
TOO OPTIMISTIC...RECENT OBSERVATIONAL TRENDS ALONG WITH VIS SATL
DATA ARE SUPPORTING A GRADUAL IMPROVEMENT TO MVFR BY THIS EVE.
TO THE WEST...ANTICIPATE MVFR CONDS AT BFD AND JST TO GO BACK DOWN
TO IFR AS LOWER CIGS AND ONCL -SHRA MOVE INTO THE AREA AHEAD OF
COLD FRONT PRESSING SEWD FROM LK ERIE. UNV/AOO ENJOYING BRIEF VFR
BUT SHOULD TREND TO MVFR BASED ON UPSTREAM CIGS.
CONFIDENCE IN THE 18Z TAF PACKAGE IS SLIGHTLY BELOW AVG GIVEN THE
COMPLEX SFC PATTERN EVOLVING OVR CNTRL PA. FCST FOR LATE TNT INTO
EARLY SUNDAY LEANS TWD THE PESSIMISTIC SIDE OF THE GUIDANCE. THE
PATTERN FOR SUNDAY SUGGESTS A PROLONGED PERIOD OF LOW CIGS AND
VISBY WITH PERIODS OF -RA.
OUTLOOK...
SUN...MVFR/IFR WITH PDS OF RAIN.
MON...STG FROPA/WSHFT. MVFR/IFR BCMG MVFR/VFR CNTRL/EAST.
RAIN...POSS ENDING AS SNOW IN THE WEST.
MON NGT-TUE...MVFR WEST TO VFR EAST.
TUE-THUR...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...LA CORTE
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
529 PM EST SAT DEC 8 2012
.SYNOPSIS...
WARMING SOUTHWEST FLOW WILL PERSIST OVER THE REGION THIS WEEKEND.
SHOWER CHANCES ARE EXPECTED TO INCREASE BY MONDAY OUT AHEAD OF AN
APPROACHING COLD FRONT. COOLER HIGH PRESSURE WILL MOVE BACK INTO
THE CAROLIANS FOR MID WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
500 PM UPDATE...A BAND OF LIGHT PRECIP HAS MOVED INTO THE UPSTATE SC
AND NE GEORGIA THIS AFTERNOON AND IT WILL CONTINUE TO PROGRESS EAST
ACROSS SC PEDIMENT THROUGH TONIGHT. PRECIP AMOUNTS SHOULD BE LIGHT
AND SOME LOCAL PATCHES OF FOG COULD ACCOMPANY THE BAND OF PRECIP.
THE LATEST RUC INDICATES THAT THE SHOWER ACTIVITY WILL DECREASE BY
LATE TONIGHT. ANOTHER AREAS OF FOG WILL DEVELOP ACROSS MUCH OF OUR
CWA TONIGHT INTO TOMORROW MORNING.
AS OF 200 PM...A PLUME OF GULF MOISTURE CAN BE SEEN ON VISIBLE
SATELLITE IMAGERY STREAMING WITHIN LLVL SWLY RETURN FLOW...WITH
LEADING EDGE OF STRATUS AND LGT SHWRS ENTERING THE WRN PORTIONS OF
THE CWFA. BOTH THE NAM AND GFS KEEP MOST OF THE ASSOCIATED ISENT
LIFT AND RH CONFINED TO THE SW NC MTNS AND UPR SAVANNAH VLY INTO
THIS EVENING...AS FLOW HAS ANTICYCLONIC CURVATURE AND HAS DOWNSLOPE
COMPONENT TO THE EAST. WITH THAT SAID...OVERALL INCREASING CLOUD
COVER AND POP IS EXPECTED ACRS THE ENTIRE AREA TNGT...AS A BRIEF
PERIOD OF ISENT LIFT AND RH TRANSLATES WEST TO EAST ACRS THE AREA.
TEMPS WILL BE 10-15 DEG ABOVE NORMAL OVERNIGHT...DROPPING ONLY INTO
THE MID 40S TO LWR 50S.
SUNDAY...GUIDANCE SHOWS THE CWFA COMPLETELY WITHIN THE WARM SECTOR
OF A DEVELOPING LOW PRES SYS OVR THE MID MS VLY. ISENT LIFT WEAKENS
AND DEEPER RH SHIFTS EAST. FCST SNDGS DO SHOW SOME SBCAPE...ESP ACRS
THE PIEDMONT...AS CLOUDS BREAK OUT AND TEMPS WARM INTO THE UPR 60S
TO NEAR 70. HOWEVER...A MID LVL INVERSION IS LIKELY TO CAP ANY
DEEPER CONVECTION. BESIDES LIMITED INSTBY...NO SIGNIFICANT MID OR
UPR LVL FORCING....AND LLVL LIFT WILL BE CONFINED TO SWLY UPSLOPE
FLOW IN THE SW NC MTNS. SO I HAVE POPS TAPERING OFF FROM CHC MTNS
AND SLGT CHC PIEDMONT IN THE MORNING TO ONLY A SLGT CHC IN THE NC
FOOTHILLS/NW PIEDMONT BY EARLY EVENING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM SATURDAY...THE MAIN FEATURE FOR THE SHORT RANGE
CONTINUES TO BE THE COLD FRONTAL PASSAGE LATE MONDAY OR MONDAY NITE.
THE GUIDANCE IN GENERAL SEEMS TO HAVE SLOWED SLIGHTLY WITH FROPA.
THAT SAID...THERE IS STILL SOME SPREAD IN THE TIMING OF THE FRONT.
THERE IS ALSO DISAGREEMENT ON THE DEVELOPMENT OF A SFC WAVE AND
WHETHER OR NOT IT MOVES ACROSS THE CWFA. THE GUIDANCE DOES AGREE
THAT ANY LINGERING LIGHT PRECIP SUNDAY EVENING WILL END BEFORE
MIDNIGHT AS LIFT DIMINISHES AND LOW LEVEL MOISTURE BECOMES SHALLOW.
HOWEVER...DEEPER MOISTURE AND FORCING ASSOCIATED WITH THE
APPROACHING FRONT WILL MOVE INTO THE MTNS AFTER MIDNIGHT SO PRECIP
CHC RETURNS BY DAYBREAK. WITH THE CONTINUED CLOUDS...SLY FLOW AND
HIGH THICKNESS VALUES...LOWS WILL BE 10 TO 20 DEGREES ABOVE NORMAL.
WITH THE FROPA TENDING TO SLOW...THIS ALSO SLOWS THE INCREASE IN
MOISTURE AND FORCING OUTSIDE OF THE MTNS. THEREFORE...DO NOT BRING
ANY CHC POP TO THE NC PIEDMONT AND ERN UPSTATE UNTIL LATE AFTERNOON
WITH CHC ACROSS THE FOOTHILLS AND WRN UPSTATE BY EARLY AFTERNOON.
THERE IS AGREEMENT THAT THE MTNS WILL SEE PRECIP ON MONDAY...BUT IT
IS SLOWED AS WELL...SO SHOW A SLOW INCREASE THRU LIKELY TO CAT POP
BY LATE IN THE DAY. THERE IS STILL LITTLE IN THE WAY OF SFC
INSTABILITY...BUT THERE LOOKS TO BE SOME WEAK ELEVATED INSTABILITY
AS LAPSE RATES INCREASE THRU THE DAY. THUNDER COULD DEVELOP JUST
ABOUT ANYWHERE EXCEPT THE NRN FOOTHILLS AND ALL BUT THE FAR SWRN NC
MTNS. THE FRONT LOOKS TO MOVE ACROSS THE CWFA MON NITE. SHEAR STILL
EXPECTED TO BE VERY STRONG WITH SOME HELICITY DEVELOPING. WITH THE
WEAK ELEVATED INSTABILITY...SVR QLCS STORMS COULD DEVELOP. IF THE
SFC LOW FORMS ALONG THE FRONT AND MOVES ACROSS THE I-85 OR SOUTH
CORRIDOR...THEN SVR CHC WOULD INCREASE AS LOW LEVEL FORCING AND
HELICITY COULD BE HIGHER. THIS COULD ALSO SLOW THE MOVEMENT OF THE
FRONT KEEPING SVR CHC INTO THE EVENING OR EVEN LATER. HAVE LIMITED
CAT POP TO THE MTNS FOR THE EVENING AND LIKELY ALL OTHER AREAS GIVEN
THE EXPECT TIMING UNCERTAINTY. THE GUIDANCE AGREES THAT LOWS MON
NITE AND PARTIAL THICKNESSES WILL BE HIGHER THAN PREV FCST. IN
ADDITION...GUIDANCE IS TRENDING AWAY FROM ANY TRADITIONAL NW FLOW
TYPE PRECIP. THEREFORE... HAVE REMOVED ANY SNOW MENTION LATE MON
NITE.
PRECIP SHUD DIMINISH TUE MORNING WITH ONLY SOME LINGERING ISOLATED
SHRA TUE AFTERNOON SOUTH OF I-85. HIGHS SHUD BE WARMER THAN EARLIER
EXPECTED AS WELL...NEAR NORMAL MTNS AND 5 TO 10 DEGREES ABOVE NORMAL
ELSEWHERE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AT 240 PM EST SATURDAY...THE AFOREMENTIONED FRONTAL BOUNDARY SHOULD
GRADUALLY GET A PUSH EAST TUESDAY NIGHT...AS A SECONDARY UPSTREAM
TROF INFLUENCES SENSIBLE WEATHER. THIS SHOULD CONCLUDE PRECIPITATION
CHANCES ACROSS OUR FORECAST AREA (FA). ALTHOUGH PRECIPITATION WILL
EITHER END OR EXIT...SOUNDING DATA SUGGESTS CLOUDS WILL LINGER MUCH
OF TUESDAY NIGHT...AND PLAN TO HOLD THAT LINE.
A LARGE AREA OF SURFACE HIGH PRESSURE WILL THEN SETTLE ACROSS OUR
FORECAST AREA (FA) WEDNESDAY AND THURSDAY...WHILE A FLAT 500 MB
RIDGE PREVAILS. THIS SHOULD SPELL QUIET WEATHER CONDITIONS DURING
MID WEEK.
AS WE REACH TOWARD THE START OF NEXT WEEKEND...THE H5 RIDGE WILL
HAVE SHIFTED OFF INTO THE ATLANTIC...AS WELL AS THE SURFACE HIGH.
SOUTHWESTERLY FLOW AT THE SURFACE AND ALOFT WILL BEGIN TO DRIVE
DEEPER MOISTURE INTO OUR REGION FRIDAY NIGHT...AND WILL PROBABLY
LAST THROUGH MUCH OF THE WEEKEND.
WARM AIR ADVECTION PRECIPITATION MAY BREAK OUT OVER THE NC MOUNTAINS
IN THE WEE HOURS SATURDAY MORNING. INCOMING CLOUDS SHOULD CAP
TEMPERATURES ABOVE FREEZING...SO AT THIS POINT WE ARE PAINTING
LIQUID AS THE PRECIPITATION TYPE. THE WARM AIR ADVECTION PATTERN
WILL THEN GRADUALLY ENCOMPASS MUCH OF OUR FA SATURDAY AND SATURDAY
NIGHT WITH A CHANCE OF SHOWERS. WILL HOLD POPS IN THE CHANCE FIELD
THIS FAR OUT...BUT WOULD NOT BE SURPRISED FOR A MORE ROBUST EPISODE.
A COLD FRONT WILL THEN BE APPROACHING / OR CROSSING / OUR REGION
LATE SATURDAY NIGHT OR BEYOND.
THE GFS IS VERY ROBUST WITH ITS PRECIPITATION FIELDS WHILE THE NEW
EUROPEAN MODEL...ALTHOUGH NOT AS BULLISH...HAS BROUGHT MORE QPF INTO
OUR FA AT THE START OF NEXT WEEKEND...COMPARED TO ITS 00Z RUN.
THERE SEEMS TO BE VERY LITTLE TO QUIBBLE WITH AS FAR AS TEMPERATURES
ARE CONCERNING...WITH SOME MINOR ADJUSTMENTS DURING THOSE PERIODS
WHEN CLOUDS ARE EXITING OR ENTERING THE FA.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR AT LEAST INTO THIS EVENING...WITH VARIABLE AMTS OF
CIRRUS AND SW WND THAT SHUD STAY UNDER 10 KTS. LATER TNGT...MOISTURE
WILL TRY TO WORK IN FROM THE WEST. GUIDANCE KEEPS ANY LOW CIGS
VFR...BUT SOME OF THE FCST SNDGS SUGGEST CIGS MAY BE MVFR.
ALSO...WITH MOIST SWLY BL FLOW...THERE MAY BE SOME VSBY RESTRICTIONS
TOWARD DAYBREAK. GUIDANCE IN GENERAL AGREEMENT ON IMPROVING
CONDITIONS BACK TO VFR BY MIDDAY SUNDAY.
ELSEWHERE...ANOTHER CHALLENGING SET OF TAFS. AN AREA OF MVFR STRATUS
WITH SOME -SHRA IS BEING ADVECTED INTO THE SW NC MTNS AND UPR
SAVANNAH VLY. THE CIGS SEEM TO BE LIFTING WITH THE HEAT OF THE
DAY...SO EXPECT THE UPSTATE SITES TO REMAIN VFR (ALTHO BRIEF PERIOD
OF MVFR CIGS IS POSSIBLE...ESP AT KAND). THINK THE LOW CLOUDS WILL
HAVE SOME TROUBLE CROSSING THE CENTRAL NC MTNS TO KAVL AND FURTHER
EAST...DUE TO DOWNSLOPE. TONIGHT...LIFT AND MOISTURE INCREASE...SO
EXPECTING INCREASE IN STRATUS COVERAGE. SOME OF THE MOS IS HITTING
FOG FAIRLY HARD IN LOCATIONS THAT HAD FOG THIS MORNING. I DON/T
THINK CONDITIONS WILL BE AS GOOD FOR WIDESPREAD FOG...BUT WILL KEEP
MENTION OF VSBY RESTRICTIONS LATE TNGT INTO SUNDAY MORNING.
CONDITIONS ARE EXPECTED TO IMPROVE AFTER DAYBREAK.
OUTLOOK...CONDITIONS ARE EXPECTED TO IMPROVE TO VFR ON SUNDAY. THEN
PATCHY FOG AND STRATUS WILL BE POSSIBLE AGAIN MONDAY MORNING. A
STRONG COLD FRONT WILL ENTER THE REGION ON MONDAY AND PUSH THRU
OVERNIGHT MONDAY NIGHT...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS
ALONG WITH GUSTY WINDS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...ARK/JOH
SHORT TERM...RWH
LONG TERM...TS
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
801 AM EST SAT DEC 8 2012
.SYNOPSIS...
WARMING SOUTHWEST FLOW WILL BE FEATURED ACROSS THE REGION THIS
WEEKEND. SHOWER CHANCES ARE EXPECTED TO INCREASE BY MONDAY OUT AHEAD
OF AN APPROACHING COLD FRONT. HIGH PRESSURE MOVE BACKS IN FOR MID
WEEK WITH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 745 AM...SEVERAL METARS ACRS THE NC FOOTHILLS AND NW PIEDMONT
WERE STILL REPORTING VSBY OF 1/4 OR LESS. THE 12Z GSO SNDG SHOWS
STRONG INVERSION ABOVE THE FOG/STRATUS LAYER...WHILE IR SATELLITE
SHOWS PLENTY OF THICK CIRRUS STREAMING ACRS THE AREA. SO I THINK THE
FOG WILL BE A BIT SLOW TO LIFT...AND HENCE HAVE EXTENDED THE DENSE
FOG ADV UNTIL 10 AM. OTHERWISE...NO CHANGES.
630 AM UPDATE...06Z NAM INDICATING SOMEWHAT MORE UNSTABLE ATMOSPHERE
THIS AFTERNOON...PARTICULARLY IN THE MTNS WHERE MUCAPE VALUES NEAR
300 J/KG ARE SEEN ON PROG SOUNDINGS. FORCING STILL NOT ALL THAT
IMPRESSIVE AND HAVE MAINTAINED SLIGHT CHANCE TO LOW CHANCE POPS.
TSTM CHANCES STILL LOW ENOUGH THAT NO MENTION NEEDED IN FCST.
AS OF 300 AM SAT...DENSE FOG BEING OBSERVED ACROSS PARTS OF THE
CWFA...MAINLY THE NC FOOTHILLS...BUT ALSO AT SOME SITES IN THE LOWER
SC PIEDMONT. CONDITIONS HAVE BEEN SOMEWHAT STABLE FOR A COUPLE OF
HOURS NOW AND SOME SITES HAVE ALREADY SEEN DENSE FOG DEVELOP AND
THEN THIN OUT. THIS IS BELIEVED TO HAVE HAPPENED DUE TO SETTLING OF
FOG DROPLETS AS THE TOP OF THE FOG LAYER IS KEPT WARMER BY HIGHER
CLOUDS PASSING OVERHEAD. SOME DRYING WAS INDICATED ON RAP LOW LEVEL
RH AND PROG SOUNDINGS AND THIS COULD HAVE ALSO CONTRIBUTED.
NONETHELESS...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE NC
FOOTHILLS AREA WHERE VISIBILITIES HAVE REMAINED LOW IN A CONTIGUOUS
AREA. RAPID IMPROVEMENT IS EXPECTED AFTER SUNRISE.
WEAK HIGH PRESSURE REMAINS OVER THE SOUTH ATLANTIC COAST THROUGH THE
PERIOD...MAINTAINING SOUTHWESTERLY LOW TO MID LEVEL FLOW ACROSS THE
CWFA. MOISTURE IN TERMS OF 850MB DEWPOINTS AND 850-700MB RH
INCREASES AS A RESULT. ISENTROPIC VERTICAL MOTION IS GENERALLY
NEUTRAL WITH ONLY GRADUAL INCREASES IN 850MB TEMPS NOTED. THE FLOW
IS SOMEWHAT UPSLOPING BUT THE SOUTHWEST ORIENTATION IS ONLY LIKELY
TO PRODUCE POPS OVER OUR SOUTHWEST MTNS. THIS LOOKS TO BE THE BEST
AVAILABLE FORCING DURING THE DAY SATURDAY. THE GFS POP EVOLUTION
SEEMED TO BEST REFLECT THAT SO I BASED TRENDS ON IT DURING THAT
TIME. HIGHEST POPS LOOK TO BE AFTER 00Z SUN AS POCKET OF MIDLEVEL Q
VECTOR CONVERGENCE MOVES NORTHWARD ACROSS THE CWFA WHILE MOISTURE
CONTINUES TO STREAM IN.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE MAIN FOCUS FOR THE SHORT RANGE WILL BE
THE PASSAGE OF A COLD FRONT LATE IN THE PERIOD. FOR SUNDAY AND
SUNDAY NIGHT...WE WILL CONTINUE TO HAVE TO DEAL WITH THE UNCERTAIN
BEGINNINGS OF PRE-FRONTAL SHOWER ACTIVITY. LOW LEVEL FORCING AND
MOISTURE LOOK ADEQUATE AS THEY HAVE FOR THE LAST FEW MODEL RUNS...
AND THE GFS/NAM SHOW A WEAK UPPER WAVE MOVING OVERHEAD IN THE
STRENGTHENING SW FLOW ALOFT. THAT SHOULD BE ENOUGH TO JUSTIFY
CARRYING A LOW END 20-30 PRECIP CHANCE TO ACCOUNT FOR SOME SCATTERED
LIGHT SHOWER ACTIVITY AND TO MATCH THE FCST FROM NEIGHBORING
OFFICES. DO NOT EXPECT THIS TO AMOUNT TO MUCH. TEMPS SUNDAY ARE
STILL A BIT PROBLEMATIC...ALTHO WE ARE LESS LIKELY TO BE BOTHERED
WITH ANY LINGERING COOL POOL AND WARM ADVECTION SHOULD ALLOW FOR
U60S/L70S OUTSIDE THE MTNS IN SPITE OF CLOUD COVER. EXPECT SUNDAY
NIGHT TO BE QUITE MILD FOR DECEMBER.
WHICH BRINGS US TO MONDAY. THERE HAS BEEN DISAGREEMENT AMONG MODEL
SOLUTIONS AS TO THE TIMING OF THE FRONTAL PASSAGE EVER SINCE THIS
EVENT CAME ONTO THE HORIZON...BUT NOW THE OPERATIONAL RUNS SEEM TO
BE IN BETTER AGREEMENT WITH A FOCUS ON LATE MONDAY OR EARLY TUESDAY
MORNING. THE MODELS SHOW AN EXCELLENT SWATH OF FORCING AND DEEP
MOISTURE APPROACHING FROM THE WEST EARLY MONDAY. THE PROBLEM IS THAT
THIS THING MAY BE WEAKENING THE WHOLE WAY AS IT MOVES IN...AS THE
MAIN SHORT WAVE LIFTS PAST TO THE NW AND THE BEST UPPER DIVERGENCE
DOES THE SAME. LOW LEVEL FORCING SHOULD CARRY A PRECIP BAND INTO THE
NC MTNS BY THE AFTERNOON...SO A LIKELY POP IS STILL WARRANTED AS IN
THE RECENT MOSGUIDE. HAVE EXTENDED THE LOW END LIKELY EAST ACROSS
THE FOOTHILLS AND PIEDMONT LATE IN THE DAY ON THE STRENGTH OF THE
LOW LEVEL FORCING. THE BIG QUESTION IS THE SEVERE WEATHER POTENTIAL.
CONFIDENCE IS GREATER IN THE POTENTIAL FOR STRONG SHEAR AS A LOW
LEVEL JET MOVES NE AHEAD OF THE FRONT ON MONDAY. IF THE GFS IS
CORRECT...THE PIEDMONT OF THE CAROLINAS WILL SEE ENOUGH BUOYANCY
THAT WE WILL HAVE TO WORRY ABOUT WIND DAMAGE AND PERHAPS AN ISOLATED
BRIEF TORNADO IF THE CONVECTIVE MODE IS LINEAR. THAT REMAINS A BIG
IF. THE NAM LIMITS THE POTENTIAL TO NE GEORGIA AND UPSTATE SC S AND
E OF I-85. THE ECMWF IS NOT IMPRESSED. WILL NOT TALK THIS UP IN THE
HWO JUST YET...BUT WILL KEEP IT SIMMERING ON A BACK BURNER. WILL
HOWEVER CONTINUE TO MENTION SOME THUNDER MONDAY AFTERNOON AND
EVENING OVER THE EASTERN ZONES. PRECIP CHANCES GRADUALLY DIMINISH
MONDAY NIGHT AS THE FRONT WEAKENS E OF THE FCST AREA.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AT 230 AM EST SATURDAY...A BROAD AND FAIRLY DEEP TROUGH WILL BE OVER
THE CENTER OF NORTH AMERICA ON TUESDAY. THIS TROUGH DEAMPLIFIES ON
WEDNESDAY...WHILE ANOTHER TROUGH AMPLIFIES ALONG THE WEST COAST. A
FAST MOVING SHORTWAVE OVER TEXAS WEDNESDAY AFTERNOON WILL REACH OUR
REGION THURSDAY WITH SURFACE LOW PRESSURE GENERATED IN THE GULF
BEING PULLED ACROSS FLORIDA TO THE CAROLINA COAST. THE GFS IS A BIT
FASTER WITH THIS SHORTWAVE THAN THE ECMWF.
WITH THE FASTER PROGRESSION OF THE GFS...ALL PRECIP HAD ENDED OVER
THE WESTERN CAROLINAS BY 12Z TUESDAY. HIGH PRESSURE CENTERED OVER
THE TENNESSEE AND OHIO VALLEYS THROUGH MID WEEK PROVIDING DRY
WEATHER FOR OUR REGION AS THE FRONT LINGERS OVER FLORIDA. THE
CURRENT GFS RUN HAS THE 500MB SHORTWAVE REACHING GEORGIA AT 12Z
THURSDAY WITH SOME RAIN SPREADING OVER NE GA AND THE UPSTATE. ALL
PRECIP IS WELL EAST OF I-77 BY 00Z FRIDAY. THE GFS HAS THE CHARLOTTE
AREA GETTING NEAR A HALF INCH OF RAIN AND EVEN MORE NEAR MARSHVILLE.
SURFACE HIGH CENTERED OVER THE CAROLINAS AND VIRGINIA FOR FRIDAY ON
THE GFS. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY.
THE NEW ECMWF HAS THE COLD FRONT CROSSING OUR AREA AT 12Z TUESDAY
WITH THE RAIN GRADUALLY ENDING EAST OF CHARLOTTE AROUND SUNSET. THE
HIGH IS ALIGNED ROUGHLY THE SAME ON WEDNESDAY AS ON THE GFS WITH THE
FRONT LINGERING ACROSS FLORIDA. THE SHARP 500MB SHORTWAVE WILL BE
OVER THE MISSISSIPPI RIVER 00Z THURSDAY AND OVER WESTERN GEORGIA AT
12Z THURSDAY AND DEEPER THAN THE GFS AT THAT TIME. THE BIG
DIFFERENCE IN THE PRECIP SHIELD IS THAT LITTLE IF ANY PRECIP REACHES
OUR PIEDMONT AS THE SHORTWAVE PASSES ON THURSDAY ACCORDING TO THE
ECMWF. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY AS
WELL BUT SOME PRECIP REACHING THE WESTERN MOUNTAINS EARLY SATURDAY.
TEMPERATURES NEAR NORMAL THROUGH THE MEDIUM RANGE.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...LIFR CIGS AND MVFR VSBY SHOULD PERSIST FOR AN HOUR OR TWO
AFTER SUNRISE UNTIL DIURNAL HEATING CAN BEGIN THE EVAPORATION
PROCESS. THE LIGHT FOG SHOULD QUICKLY DISSIPATE BUT IT WILL LIKELY
TAKE A COUPLE OF HOURS FOR THE LOW CIG TO BREAK UP OR LIFT. MOISTURE
WILL STILL BE PRESENT AT A HIGHER LEVEL...SO A VFR CIG WILL HOLD ON
FOR MOST OF THE DAY...WITH POSSIBLE BREAKS IN THE AFTERNOON.
GUIDANCE INDICATES SOME FOG POTENTIAL FOR LATE TONIGHT/EARLY SUNDAY
GIVEN HIGH SURFACE RH VALUES. AT THIS TIME...WILL MENTION MVFR VSBY
NEAR THE END OF THE PERIOD. SFC HIGH PRESSURE ALONG THE COAST WILL
MAINTAIN SOUTHWEST WINDS THROUGH THE PERIOD...LESS THAN 10KT.
ELSEWHERE...LIFR TO IFR CIGS SEEN ACROSS PARTS OF THE AREA WITH
BREAKS IN LOW CLOUDS EVIDENT ON SFC OBS. THE CIGS ARE EXPECTED TO
SEE SOME IMPROVEMENT IN THE FIRST COUPLE OF HOURS AFTER SUNRISE.
DENSE FOG OCCURRING OVER THE NC FOOTHILLS WILL SLOWLY ERODE...WITH
RESTRICTIONS LIKELY DISAPPEARING BY MID MORNING. SLIGHT CHANCE FOR
PRECIP OVER THE MTNS TODAY...WITH CHANCES INCREASING OVERNIGHT...BUT
ACCUMULATION FROM ANY SHOWERS THAT FORM WILL BE VERY LIGHT AND
OPERATIONAL IMPACTS WILL BE VERY MINOR. GUIDANCE HINTS AT
POSSIBILITY OF FOG DEVELOPING BY 06Z SUN ACROSS MUCH OF THE AREA.
CONFIDENCE LOW AS TO JUST HOW DENSE IT WOULD BE...SO HAVE KEPT ONLY
MVFR MENTION IN TAFS.
OUTLOOK...VFR CONDITIONS ARE EXPECTED OVERALL THRU THE WEEKEND...BUT
PATCHY FOG AND STRATUS WILL BE POSSIBLE BOTH SUNDAY AND MONDAY
MORNINGS. A STRONG COLD FRONT WILL CROSS THE REGION MONDAY OR MONDAY
NIGHT...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS ALONG WITH GUSTY
WINDS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ035-036-
056-068-069-501>510.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...ARK/WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
651 AM EST SAT DEC 8 2012
.SYNOPSIS...
WARMING SOUTHWEST FLOW WILL BE FEATURED ACROSS THE REGION THIS
WEEKEND. SHOWER CHANCES ARE EXPECTED TO INCREASE BY MONDAY OUT AHEAD
OF AN APPROACHING COLD FRONT. HIGH PRESSURE MOVE BACKS IN FOR MID
WEEK WITH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...06Z NAM INDICATING SOMEWHAT MORE UNSTABLE ATMOSPHERE
THIS AFTERNOON...PARTICULARLY IN THE MTNS WHERE MUCAPE VALUES NEAR
300 J/KG ARE SEEN ON PROG SOUNDINGS. FORCING STILL NOT ALL THAT
IMPRESSIVE AND HAVE MAINTAINED SLIGHT CHANCE TO LOW CHANCE POPS.
TSTM CHANCES STILL LOW ENOUGH THAT NO MENTION NEEDED IN FCST.
AS OF 300 AM SAT...DENSE FOG BEING OBSERVED ACROSS PARTS OF THE
CWFA...MAINLY THE NC FOOTHILLS...BUT ALSO AT SOME SITES IN THE LOWER
SC PIEDMONT. CONDITIONS HAVE BEEN SOMEWHAT STABLE FOR A COUPLE OF
HOURS NOW AND SOME SITES HAVE ALREADY SEEN DENSE FOG DEVELOP AND
THEN THIN OUT. THIS IS BELIEVED TO HAVE HAPPENED DUE TO SETTLING OF
FOG DROPLETS AS THE TOP OF THE FOG LAYER IS KEPT WARMER BY HIGHER
CLOUDS PASSING OVERHEAD. SOME DRYING WAS INDICATED ON RAP LOW LEVEL
RH AND PROG SOUNDINGS AND THIS COULD HAVE ALSO CONTRIBUTED.
NONETHELESS...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE NC
FOOTHILLS AREA WHERE VISIBILITIES HAVE REMAINED LOW IN A CONTIGUOUS
AREA. RAPID IMPROVEMENT IS EXPECTED AFTER SUNRISE.
WEAK HIGH PRESSURE REMAINS OVER THE SOUTH ATLANTIC COAST THROUGH THE
PERIOD...MAINTAINING SOUTHWESTERLY LOW TO MID LEVEL FLOW ACROSS THE
CWFA. MOISTURE IN TERMS OF 850MB DEWPOINTS AND 850-700MB RH
INCREASES AS A RESULT. ISENTROPIC VERTICAL MOTION IS GENERALLY
NEUTRAL WITH ONLY GRADUAL INCREASES IN 850MB TEMPS NOTED. THE FLOW
IS SOMEWHAT UPSLOPING BUT THE SOUTHWEST ORIENTATION IS ONLY LIKELY
TO PRODUCE POPS OVER OUR SOUTHWEST MTNS. THIS LOOKS TO BE THE BEST
AVAILABLE FORCING DURING THE DAY SATURDAY. THE GFS POP EVOLUTION
SEEMED TO BEST REFLECT THAT SO I BASED TRENDS ON IT DURING THAT
TIME. HIGHEST POPS LOOK TO BE AFTER 00Z SUN AS POCKET OF MIDLEVEL Q
VECTOR CONVERGENCE MOVES NORTHWARD ACROSS THE CWFA WHILE MOISTURE
CONTINUES TO STREAM IN.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE MAIN FOCUS FOR THE SHORT RANGE WILL BE
THE PASSAGE OF A COLD FRONT LATE IN THE PERIOD. FOR SUNDAY AND
SUNDAY NIGHT...WE WILL CONTINUE TO HAVE TO DEAL WITH THE UNCERTAIN
BEGINNINGS OF PRE-FRONTAL SHOWER ACTIVITY. LOW LEVEL FORCING AND
MOISTURE LOOK ADEQUATE AS THEY HAVE FOR THE LAST FEW MODEL RUNS...
AND THE GFS/NAM SHOW A WEAK UPPER WAVE MOVING OVERHEAD IN THE
STRENGTHENING SW FLOW ALOFT. THAT SHOULD BE ENOUGH TO JUSTIFY
CARRYING A LOW END 20-30 PRECIP CHANCE TO ACCOUNT FOR SOME SCATTERED
LIGHT SHOWER ACTIVITY AND TO MATCH THE FCST FROM NEIGHBORING
OFFICES. DO NOT EXPECT THIS TO AMOUNT TO MUCH. TEMPS SUNDAY ARE
STILL A BIT PROBLEMATIC...ALTHO WE ARE LESS LIKELY TO BE BOTHERED
WITH ANY LINGERING COOL POOL AND WARM ADVECTION SHOULD ALLOW FOR
U60S/L70S OUTSIDE THE MTNS IN SPITE OF CLOUD COVER. EXPECT SUNDAY
NIGHT TO BE QUITE MILD FOR DECEMBER.
WHICH BRINGS US TO MONDAY. THERE HAS BEEN DISAGREEMENT AMONG MODEL
SOLUTIONS AS TO THE TIMING OF THE FRONTAL PASSAGE EVER SINCE THIS
EVENT CAME ONTO THE HORIZON...BUT NOW THE OPERATIONAL RUNS SEEM TO
BE IN BETTER AGREEMENT WITH A FOCUS ON LATE MONDAY OR EARLY TUESDAY
MORNING. THE MODELS SHOW AN EXCELLENT SWATH OF FORCING AND DEEP
MOISTURE APPROACHING FROM THE WEST EARLY MONDAY. THE PROBLEM IS THAT
THIS THING MAY BE WEAKENING THE WHOLE WAY AS IT MOVES IN...AS THE
MAIN SHORT WAVE LIFTS PAST TO THE NW AND THE BEST UPPER DIVERGENCE
DOES THE SAME. LOW LEVEL FORCING SHOULD CARRY A PRECIP BAND INTO THE
NC MTNS BY THE AFTERNOON...SO A LIKELY POP IS STILL WARRANTED AS IN
THE RECENT MOSGUIDE. HAVE EXTENDED THE LOW END LIKELY EAST ACROSS
THE FOOTHILLS AND PIEDMONT LATE IN THE DAY ON THE STRENGTH OF THE
LOW LEVEL FORCING. THE BIG QUESTION IS THE SEVERE WEATHER POTENTIAL.
CONFIDENCE IS GREATER IN THE POTENTIAL FOR STRONG SHEAR AS A LOW
LEVEL JET MOVES NE AHEAD OF THE FRONT ON MONDAY. IF THE GFS IS
CORRECT...THE PIEDMONT OF THE CAROLINAS WILL SEE ENOUGH BUOYANCY
THAT WE WILL HAVE TO WORRY ABOUT WIND DAMAGE AND PERHAPS AN ISOLATED
BRIEF TORNADO IF THE CONVECTIVE MODE IS LINEAR. THAT REMAINS A BIG
IF. THE NAM LIMITS THE POTENTIAL TO NE GEORGIA AND UPSTATE SC S AND
E OF I-85. THE ECMWF IS NOT IMPRESSED. WILL NOT TALK THIS UP IN THE
HWO JUST YET...BUT WILL KEEP IT SIMMERING ON A BACK BURNER. WILL
HOWEVER CONTINUE TO MENTION SOME THUNDER MONDAY AFTERNOON AND
EVENING OVER THE EASTERN ZONES. PRECIP CHANCES GRADUALLY DIMINISH
MONDAY NIGHT AS THE FRONT WEAKENS E OF THE FCST AREA.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AT 230 AM EST SATURDAY...A BROAD AND FAIRLY DEEP TROUGH WILL BE OVER
THE CENTER OF NORTH AMERICA ON TUESDAY. THIS TROUGH DEAMPLIFIES ON
WEDNESDAY...WHILE ANOTHER TROUGH AMPLIFIES ALONG THE WEST COAST. A
FAST MOVING SHORTWAVE OVER TEXAS WEDNESDAY AFTERNOON WILL REACH OUR
REGION THURSDAY WITH SURFACE LOW PRESSURE GENERATED IN THE GULF
BEING PULLED ACROSS FLORIDA TO THE CAROLINA COAST. THE GFS IS A BIT
FASTER WITH THIS SHORTWAVE THAN THE ECMWF.
WITH THE FASTER PROGRESSION OF THE GFS...ALL PRECIP HAD ENDED OVER
THE WESTERN CAROLINAS BY 12Z TUESDAY. HIGH PRESSURE CENTERED OVER
THE TENNESSEE AND OHIO VALLEYS THROUGH MID WEEK PROVIDING DRY
WEATHER FOR OUR REGION AS THE FRONT LINGERS OVER FLORIDA. THE
CURRENT GFS RUN HAS THE 500MB SHORTWAVE REACHING GEORGIA AT 12Z
THURSDAY WITH SOME RAIN SPREADING OVER NE GA AND THE UPSTATE. ALL
PRECIP IS WELL EAST OF I-77 BY 00Z FRIDAY. THE GFS HAS THE CHARLOTTE
AREA GETTING NEAR A HALF INCH OF RAIN AND EVEN MORE NEAR MARSHVILLE.
SURFACE HIGH CENTERED OVER THE CAROLINAS AND VIRGINIA FOR FRIDAY ON
THE GFS. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY.
THE NEW ECMWF HAS THE COLD FRONT CROSSING OUR AREA AT 12Z TUESDAY
WITH THE RAIN GRADUALLY ENDING EAST OF CHARLOTTE AROUND SUNSET. THE
HIGH IS ALIGNED ROUGHLY THE SAME ON WEDNESDAY AS ON THE GFS WITH THE
FRONT LINGERING ACROSS FLORIDA. THE SHARP 500MB SHORTWAVE WILL BE
OVER THE MISSISSIPPI RIVER 00Z THURSDAY AND OVER WESTERN GEORGIA AT
12Z THURSDAY AND DEEPER THAN THE GFS AT THAT TIME. THE BIG
DIFFERENCE IN THE PRECIP SHIELD IS THAT LITTLE IF ANY PRECIP REACHES
OUR PIEDMONT AS THE SHORTWAVE PASSES ON THURSDAY ACCORDING TO THE
ECMWF. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY AS
WELL BUT SOME PRECIP REACHING THE WESTERN MOUNTAINS EARLY SATURDAY.
TEMPERATURES NEAR NORMAL THROUGH THE MEDIUM RANGE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...LIFR CIGS AND MVFR VSBY SHOULD PERSIST FOR AN HOUR OR TWO
AFTER SUNRISE UNTIL DIURNAL HEATING CAN BEGIN THE EVAPORATION
PROCESS. THE LIGHT FOG SHOULD QUICKLY DISSIPATE BUT IT WILL LIKELY
TAKE A COUPLE OF HOURS FOR THE LOW CIG TO BREAK UP OR LIFT. MOISTURE
WILL STILL BE PRESENT AT A HIGHER LEVEL...SO A VFR CIG WILL HOLD ON
FOR MOST OF THE DAY...WITH POSSIBLE BREAKS IN THE AFTERNOON.
GUIDANCE INDICATES SOME FOG POTENTIAL FOR LATE TONIGHT/EARLY SUNDAY
GIVEN HIGH SURFACE RH VALUES. AT THIS TIME...WILL MENTION MVFR VSBY
NEAR THE END OF THE PERIOD. SFC HIGH PRESSURE ALONG THE COAST WILL
MAINTAIN SOUTHWEST WINDS THROUGH THE PERIOD...LESS THAN 10KT.
ELSEWHERE...LIFR TO IFR CIGS SEEN ACROSS PARTS OF THE AREA WITH
BREAKS IN LOW CLOUDS EVIDENT ON SFC OBS. THE CIGS ARE EXPECTED TO
SEE SOME IMPROVEMENT IN THE FIRST COUPLE OF HOURS AFTER SUNRISE.
DENSE FOG OCCURRING OVER THE NC FOOTHILLS WILL SLOWLY ERODE...WITH
RESTRICTIONS LIKELY DISAPPEARING BY MID MORNING. SLIGHT CHANCE FOR
PRECIP OVER THE MTNS TODAY...WITH CHANCES INCREASING OVERNIGHT...BUT
ACCUMULATION FROM ANY SHOWERS THAT FORM WILL BE VERY LIGHT AND
OPERATIONAL IMPACTS WILL BE VERY MINOR. GUIDANCE HINTS AT
POSSIBILITY OF FOG DEVELOPING BY 06Z SUN ACROSS MUCH OF THE AREA.
CONFIDENCE LOW AS TO JUST HOW DENSE IT WOULD BE...SO HAVE KEPT ONLY
MVFR MENTION IN TAFS.
OUTLOOK...VFR CONDITIONS ARE EXPECTED OVERALL THRU THE WEEKEND...BUT
PATCHY FOG AND STRATUS WILL BE POSSIBLE BOTH SUNDAY AND MONDAY
MORNINGS. A STRONG COLD FRONT WILL CROSS THE REGION MONDAY OR MONDAY
NIGHT...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS ALONG WITH GUSTY
WINDS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR NCZ035-036-
056-068-069-501>510.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
349 AM EST SAT DEC 8 2012
.SYNOPSIS...
WARMING SOUTHWEST FLOW WILL BE FEATURED ACROSS THE REGION THIS
WEEKEND. SHOWER CHANCES ARE EXPECTED TO INCREASE BY MONDAY OUT AHEAD
OF AN APPROACHING COLD FRONT. HIGH PRESSURE MOVE BACKS IN FOR MID
WEEK WITH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM SAT...DENSE FOG BEING OBSERVED ACROSS PARTS OF THE
CWFA...MAINLY THE NC FOOTHILLS...BUT ALSO AT SOME SITES IN THE LOWER
SC PIEDMONT. CONDITIONS HAVE BEEN SOMEWHAT STABLE FOR A COUPLE OF
HOURS NOW AND SOME SITES HAVE ALREADY SEEN DENSE FOG DEVELOP AND
THEN THIN OUT. THIS IS BELIEVED TO HAVE HAPPENED DUE TO SETTLING OF
FOG DROPLETS AS THE TOP OF THE FOG LAYER IS KEPT WARMER BY HIGHER
CLOUDS PASSING OVERHEAD. SOME DRYING WAS INDICATED ON RAP LOW LEVEL
RH AND PROG SOUNDINGS AND THIS COULD HAVE ALSO CONTRIBUTED.
NONETHELESS...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE NC
FOOTHILLS AREA WHERE VISIBILITIES HAVE REMAINED LOW IN A CONTIGUOUS
AREA. RAPID IMPROVEMENT IS EXPECTED AFTER SUNRISE.
WEAK HIGH PRESSURE REMAINS OVER THE SOUTH ATLANTIC COAST THROUGH THE
PERIOD...MAINTAINING SOUTHWESTERLY LOW TO MID LEVEL FLOW ACROSS THE
CWFA. MOISTURE IN TERMS OF 850MB DEWPOINTS AND 850-700MB RH
INCREASES AS A RESULT. ISENTROPIC VERTICAL MOTION IS GENERALLY
NEUTRAL WITH ONLY GRADUAL INCREASES IN 850MB TEMPS NOTED. THE FLOW
IS SOMEWHAT UPSLOPING BUT THE SOUTHWEST ORIENTATION IS ONLY LIKELY
TO PRODUCE POPS OVER OUR SOUTHWEST MTNS. THIS LOOKS TO BE THE BEST
AVAILABLE FORCING DURING THE DAY SATURDAY. THE GFS POP EVOLUTION
SEEMED TO BEST REFLECT THAT SO I BASED TRENDS ON IT DURING THAT
TIME. HIGHEST POPS LOOK TO BE AFTER 00Z SUN AS POCKET OF MIDLEVEL Q
VECTOR CONVERGENCE MOVES NORTHWARD ACROSS THE CWFA WHILE MOISTURE
CONTINUES TO STREAM IN.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE MAIN FOCUS FOR THE SHORT RANGE WILL BE
THE PASSAGE OF A COLD FRONT LATE IN THE PERIOD. FOR SUNDAY AND
SUNDAY NIGHT...WE WILL CONTINUE TO HAVE TO DEAL WITH THE UNCERTAIN
BEGINNINGS OF PRE-FRONTAL SHOWER ACTIVITY. LOW LEVEL FORCING AND
MOISTURE LOOK ADEQUATE AS THEY HAVE FOR THE LAST FEW MODEL RUNS...
AND THE GFS/NAM SHOW A WEAK UPPER WAVE MOVING OVERHEAD IN THE
STRENGTHENING SW FLOW ALOFT. THAT SHOULD BE ENOUGH TO JUSTIFY
CARRYING A LOW END 20-30 PRECIP CHANCE TO ACCOUNT FOR SOME SCATTERED
LIGHT SHOWER ACTIVITY AND TO MATCH THE FCST FROM NEIGHBORING
OFFICES. DO NOT EXPECT THIS TO AMOUNT TO MUCH. TEMPS SUNDAY ARE
STILL A BIT PROBLEMATIC...ALTHO WE ARE LESS LIKELY TO BE BOTHERED
WITH ANY LINGERING COOL POOL AND WARM ADVECTION SHOULD ALLOW FOR
U60S/L70S OUTSIDE THE MTNS IN SPITE OF CLOUD COVER. EXPECT SUNDAY
NIGHT TO BE QUITE MILD FOR DECEMBER.
WHICH BRINGS US TO MONDAY. THERE HAS BEEN DISAGREEMENT AMONG MODEL
SOLUTIONS AS TO THE TIMING OF THE FRONTAL PASSAGE EVER SINCE THIS
EVENT CAME ONTO THE HORIZON...BUT NOW THE OPERATIONAL RUNS SEEM TO
BE IN BETTER AGREEMENT WITH A FOCUS ON LATE MONDAY OR EARLY TUESDAY
MORNING. THE MODELS SHOW AN EXCELLENT SWATH OF FORCING AND DEEP
MOISTURE APPROACHING FROM THE WEST EARLY MONDAY. THE PROBLEM IS THAT
THIS THING MAY BE WEAKENING THE WHOLE WAY AS IT MOVES IN...AS THE
MAIN SHORT WAVE LIFTS PAST TO THE NW AND THE BEST UPPER DIVERGENCE
DOES THE SAME. LOW LEVEL FORCING SHOULD CARRY A PRECIP BAND INTO THE
NC MTNS BY THE AFTERNOON...SO A LIKELY POP IS STILL WARRANTED AS IN
THE RECENT MOSGUIDE. HAVE EXTENDED THE LOW END LIKELY EAST ACROSS
THE FOOTHILLS AND PIEDMONT LATE IN THE DAY ON THE STRENGTH OF THE
LOW LEVEL FORCING. THE BIG QUESTION IS THE SEVERE WEATHER POTENTIAL.
CONFIDENCE IS GREATER IN THE POTENTIAL FOR STRONG SHEAR AS A LOW
LEVEL JET MOVES NE AHEAD OF THE FRONT ON MONDAY. IF THE GFS IS
CORRECT...THE PIEDMONT OF THE CAROLINAS WILL SEE ENOUGH BUOYANCY
THAT WE WILL HAVE TO WORRY ABOUT WIND DAMAGE AND PERHAPS AN ISOLATED
BRIEF TORNADO IF THE CONVECTIVE MODE IS LINEAR. THAT REMAINS A BIG
IF. THE NAM LIMITS THE POTENTIAL TO NE GEORGIA AND UPSTATE SC S AND
E OF I-85. THE ECMWF IS NOT IMPRESSED. WILL NOT TALK THIS UP IN THE
HWO JUST YET...BUT WILL KEEP IT SIMMERING ON A BACK BURNER. WILL
HOWEVER CONTINUE TO MENTION SOME THUNDER MONDAY AFTERNOON AND
EVENING OVER THE EASTERN ZONES. PRECIP CHANCES GRADUALLY DIMINISH
MONDAY NIGHT AS THE FRONT WEAKENS E OF THE FCST AREA.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AT 230 AM EST SATURDAY...A BROAD AND FAIRLY DEEP TROUGH WILL BE OVER
THE CENTER OF NORTH AMERICA ON TUESDAY. THIS TROUGH DEAMPLIFIES ON
WEDNESDAY...WHILE ANOTHER TROUGH AMPLIFIES ALONG THE WEST COAST. A
FAST MOVING SHORTWAVE OVER TEXAS WEDNESDAY AFTERNOON WILL REACH OUR
REGION THURSDAY WITH SURFACE LOW PRESSURE GENERATED IN THE GULF
BEING PULLED ACROSS FLORIDA TO THE CAROLINA COAST. THE GFS IS A BIT
FASTER WITH THIS SHORTWAVE THAN THE ECMWF.
WITH THE FASTER PROGRESSION OF THE GFS...ALL PRECIP HAD ENDED OVER
THE WESTERN CAROLINAS BY 12Z TUESDAY. HIGH PRESSURE CENTERED OVER
THE TENNESSEE AND OHIO VALLEYS THROUGH MID WEEK PROVIDING DRY
WEATHER FOR OUR REGION AS THE FRONT LINGERS OVER FLORIDA. THE
CURRENT GFS RUN HAS THE 500MB SHORTWAVE REACHING GEORGIA AT 12Z
THURSDAY WITH SOME RAIN SPREADING OVER NE GA AND THE UPSTATE. ALL
PRECIP IS WELL EAST OF I-77 BY 00Z FRIDAY. THE GFS HAS THE CHARLOTTE
AREA GETTING NEAR A HALF INCH OF RAIN AND EVEN MORE NEAR MARSHVILLE.
SURFACE HIGH CENTERED OVER THE CAROLINAS AND VIRGINIA FOR FRIDAY ON
THE GFS. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY.
THE NEW ECMWF HAS THE COLD FRONT CROSSING OUR AREA AT 12Z TUESDAY
WITH THE RAIN GRADUALLY ENDING EAST OF CHARLOTTE AROUND SUNSET. THE
HIGH IS ALIGNED ROUGHLY THE SAME ON WEDNESDAY AS ON THE GFS WITH THE
FRONT LINGERING ACROSS FLORIDA. THE SHARP 500MB SHORTWAVE WILL BE
OVER THE MISSISSIPPI RIVER 00Z THURSDAY AND OVER WESTERN GEORGIA AT
12Z THURSDAY AND DEEPER THAN THE GFS AT THAT TIME. THE BIG
DIFFERENCE IN THE PRECIP SHIELD IS THAT LITTLE IF ANY PRECIP REACHES
OUR PIEDMONT AS THE SHORTWAVE PASSES ON THURSDAY ACCORDING TO THE
ECMWF. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY AS
WELL BUT SOME PRECIP REACHING THE WESTERN MOUNTAINS EARLY SATURDAY.
TEMPERATURES NEAR NORMAL THROUGH THE MEDIUM RANGE.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
09Z KCLT UPDATE...CURRENT CIG LIKELY TO PERSIST TO A COUPLE OF HOURS
AFTER SUNRISE. LATEST MESOSCALE MODEL SOUNDINGS INDICATE THE
SATURATED LAYER REMAINING UNCHANGED IN THICKNESS. WEAK SOUTHWESTERLY
FLOW COULD ADVECT IN SOMEWHAT DRIER AIR FROM THE SOUTHWEST /PER SFC
OBS/ BUT THE FLOW WILL BE SLOW TO GET GOING GIVEN THE LOW CIGS AND
SLOW HEATING. HAVE PUSHED BACK THE DISSIPATION OF THE CIG TO 15Z AND
IF ANYTHING THIS WILL PROBABLY HAVE TO BE DELAYED FURTHER...BUT WILL
MONITOR SKY COVER TRENDS AROUND THE REGION AND TRY TO INCREASE
CONFIDENCE IN DISSIPATION FOR THE 12Z ISSUANCE.
AT KCLT AND ELSEWHERE...AVIATION FORECAST CONTINUES TO BE QUITE
TRICKY. IFR TO LIFR CIGS OBSERVED ATTM ACROSS MUCH OF THE FCST
AREA...PRIMARILY OVER THE ERN PIEDMONT. 1000-850MB LAYER DRIES A BIT
OVER THAT AREA OVER THE NEXT FEW HOURS WHICH COULD EITHER HELP
EVAPORATE FOG...OR PROMOTE CLEARING ABOVE THE FOG LAYER WHICH WOULD
ALLOW IT TO BECOME MORE DENSE. CIRRUS MOVING ACROSS THE REGION WILL
LIMIT CLOUD TOP COOLING WHICH IS ANOTHER LIMITING FACTOR FOR FOG/LOW
STRATUS DEVELOPMENT. AN EXAMINATION OF MODEL SOUNDINGS SHOWS THE SFC
SATURATED LAYER BECOMING THINNER WITH TIME TONIGHT. THIS DOES NOT
NECESSARILY MEAN OPERATIONAL CONDITIONS WILL IMPROVE AT AFFECTED
AIRPORTS BUT IT IMPLIES LESS PERSISTENT RESTRICTIONS. HAVE GENERALLY
MAINTAINED PRESENT CONDITIONS UNTIL JUST AFTER SUNRISE...WITH SOME
SLIGHT IMPROVEMENT LATE AS THE DRYING OCCURS ALOFT. ONCE THE
OVERNIGHT FOG/STRATUS LIFT IN THE MORNING SOME VFR CLOUDS WILL
REMAIN IN PLACE THROUGH THE DAY. GUIDANCE HINTS AT SOME
REDEVELOPMENT OF RESTRICTIONS NEAR THE END OF THE PERIOD...AFTER 00Z
SUN...BUT CONFIDENCE CURRENTLY LOW SO DO NOT WANT TO INCLUDE IN TAFS
YET.
OUTLOOK...VFR CONDITIONS ARE EXPECTED OVERALL THRU THE WEEKEND...BUT
PATCHY FOG AND STRATUS WILL BE POSSIBLE BOTH SUNDAY AND MONDAY
MORNINGS. A STRONG COLD FRONT WILL CROSS THE REGION MONDAY OR MONDAY
NIGHT...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS ALONG WITH GUSTY
WINDS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR NCZ035-036-
056-068-069-501>510.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
319 AM EST SAT DEC 8 2012
.SYNOPSIS...
WARMING SOUTHWEST FLOW WILL BE FEATURED ACROSS THE REGION THIS
WEEKEND. SHOWER CHANCES ARE EXPECTED TO INCREASE BY MONDAY OUT AHEAD
OF AN APPROACHING COLD FRONT. HIGH PRESSURE MOVE BACKS IN FOR MID
WEEK WITH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM SAT...DENSE FOG BEING OBSERVED ACROSS PARTS OF THE
CWFA...MAINLY THE NC FOOTHILLS...BUT ALSO AT SOME SITES IN THE LOWER
SC PIEDMONT. CONDITIONS HAVE BEEN SOMEWHAT STABLE FOR A COUPLE OF
HOURS NOW AND SOME SITES HAVE ALREADY SEEN DENSE FOG DEVELOP AND
THEN THIN OUT. THIS IS BELIEVED TO HAVE HAPPENED DUE TO SETTLING OF
FOG DROPLETS AS THE TOP OF THE FOG LAYER IS KEPT WARMER BY HIGHER
CLOUDS PASSING OVERHEAD. SOME DRYING WAS INDICATED ON RAP LOW LEVEL
RH AND PROG SOUNDINGS AND THIS COULD HAVE ALSO CONTRIBUTED.
NONETHELESS...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE NC
FOOTHILLS AREA WHERE VISIBILITIES HAVE REMAINED LOW IN A CONTIGUOUS
AREA. RAPID IMPROVEMENT IS EXPECTED AFTER SUNRISE.
WEAK HIGH PRESSURE REMAINS OVER THE SOUTH ATLANTIC COAST THROUGH THE
PERIOD...MAINTAINING SOUTHWESTERLY LOW TO MID LEVEL FLOW ACROSS THE
CWFA. MOISTURE IN TERMS OF 850MB DEWPOINTS AND 850-700MB RH
INCREASES AS A RESULT. ISENTROPIC VERTICAL MOTION IS GENERALLY
NEUTRAL WITH ONLY GRADUAL INCREASES IN 850MB TEMPS NOTED. THE FLOW
IS SOMEWHAT UPSLOPING BUT THE SOUTHWEST ORIENTATION IS ONLY LIKELY
TO PRODUCE POPS OVER OUR SOUTHWEST MTNS. THIS LOOKS TO BE THE BEST
AVAILABLE FORCING DURING THE DAY SATURDAY. THE GFS POP EVOLUTION
SEEMED TO BEST REFLECT THAT SO I BASED TRENDS ON IT DURING THAT
TIME. HIGHEST POPS LOOK TO BE AFTER 00Z SUN AS POCKET OF MIDLEVEL Q
VECTOR CONVERGENCE MOVES NORTHWARD ACROSS THE CWFA WHILE MOISTURE
CONTINUES TO STREAM IN.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE MAIN FOCUS FOR THE SHORT RANGE WILL BE
THE PASSAGE OF A COLD FRONT LATE IN THE PERIOD. FOR SUNDAY AND
SUNDAY NIGHT...WE WILL CONTINUE TO HAVE TO DEAL WITH THE UNCERTAIN
BEGINNINGS OF PRE-FRONTAL SHOWER ACTIVITY. LOW LEVEL FORCING AND
MOISTURE LOOK ADEQUATE AS THEY HAVE FOR THE LAST FEW MODEL RUNS...
AND THE GFS/NAM SHOW A WEAK UPPER WAVE MOVING OVERHEAD IN THE
STRENGTHENING SW FLOW ALOFT. THAT SHOULD BE ENOUGH TO JUSTIFY
CARRYING A LOW END 20-30 PRECIP CHANCE TO ACCOUNT FOR SOME SCATTERED
LIGHT SHOWER ACTIVITY AND TO MATCH THE FCST FROM NEIGHBORING
OFFICES. DO NOT EXPECT THIS TO AMOUNT TO MUCH. TEMPS SUNDAY ARE
STILL A BIT PROBLEMATIC...ALTHO WE ARE LESS LIKELY TO BE BOTHERED
WITH ANY LINGERING COOL POOL AND WARM ADVECTION SHOULD ALLOW FOR
U60S/L70S OUTSIDE THE MTNS IN SPITE OF CLOUD COVER. EXPECT SUNDAY
NIGHT TO BE QUITE MILD FOR DECEMBER.
WHICH BRINGS US TO MONDAY. THERE HAS BEEN DISAGREEMENT AMONG MODEL
SOLUTIONS AS TO THE TIMING OF THE FRONTAL PASSAGE EVER SINCE THIS
EVENT CAME ONTO THE HORIZON...BUT NOW THE OPERATIONAL RUNS SEEM TO
BE IN BETTER AGREEMENT WITH A FOCUS ON LATE MONDAY OR EARLY TUESDAY
MORNING. THE MODELS SHOW AN EXCELLENT SWATH OF FORCING AND DEEP
MOISTURE APPROACHING FROM THE WEST EARLY MONDAY. THE PROBLEM IS THAT
THIS THING MAY BE WEAKENING THE WHOLE WAY AS IT MOVES IN...AS THE
MAIN SHORT WAVE LIFTS PAST TO THE NW AND THE BEST UPPER DIVERGENCE
DOES THE SAME. LOW LEVEL FORCING SHOULD CARRY A PRECIP BAND INTO THE
NC MTNS BY THE AFTERNOON...SO A LIKELY POP IS STILL WARRANTED AS IN
THE RECENT MOSGUIDE. HAVE EXTENDED THE LOW END LIKELY EAST ACROSS
THE FOOTHILLS AND PIEDMONT LATE IN THE DAY ON THE STRENGTH OF THE
LOW LEVEL FORCING. THE BIG QUESTION IS THE SEVERE WEATHER POTENTIAL.
CONFIDENCE IS GREATER IN THE POTENTIAL FOR STRONG SHEAR AS A LOW
LEVEL JET MOVES NE AHEAD OF THE FRONT ON MONDAY. IF THE GFS IS
CORRECT...THE PIEDMONT OF THE CAROLINAS WILL SEE ENOUGH BUOYANCY
THAT WE WILL HAVE TO WORRY ABOUT WIND DAMAGE AND PERHAPS AN ISOLATED
BRIEF TORNADO IF THE CONVECTIVE MODE IS LINEAR. THAT REMAINS A BIG
IF. THE NAM LIMITS THE POTENTIAL TO NE GEORGIA AND UPSTATE SC S AND
E OF I-85. THE ECMWF IS NOT IMPRESSED. WILL NOT TALK THIS UP IN THE
HWO JUST YET...BUT WILL KEEP IT SIMMERING ON A BACK BURNER. WILL
HOWEVER CONTINUE TO MENTION SOME THUNDER MONDAY AFTERNOON AND
EVENING OVER THE EASTERN ZONES. PRECIP CHANCES GRADUALLY DIMINISH
MONDAY NIGHT AS THE FRONT WEAKENS E OF THE FCST AREA.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AT 230 AM EST SATURDAY...A BROAD AND FAIRLY DEEP TROUGH WILL BE OVER
THE CENTER OF NORTH AMERICA ON TUESDAY. THIS TROUGH DEAMPLIFIES ON
WEDNESDAY...WHILE ANOTHER TROUGH AMPLIFIES ALONG THE WEST COAST. A
FAST MOVING SHORTWAVE OVER TEXAS WEDNESDAY AFTERNOON WILL REACH OUR
REGION THURSDAY WITH SURFACE LOW PRESSURE GENERATED IN THE GULF
BEING PULLED ACROSS FLORIDA TO THE CAROLINA COAST. THE GFS IS A BIT
FASTER WITH THIS SHORTWAVE THAN THE ECMWF.
WITH THE FASTER PROGRESSION OF THE GFS...ALL PRECIP HAD ENDED OVER
THE WESTERN CAROLINAS BY 12Z TUESDAY. HIGH PRESSURE CENTERED OVER
THE TENNESSEE AND OHIO VALLEYS THROUGH MID WEEK PROVIDING DRY
WEATHER FOR OUR REGION AS THE FRONT LINGERS OVER FLORIDA. THE
CURRENT GFS RUN HAS THE 500MB SHORTWAVE REACHING GEORGIA AT 12Z
THURSDAY WITH SOME RAIN SPREADING OVER NE GA AND THE UPSTATE. ALL
PRECIP IS WELL EAST OF I-77 BY 00Z FRIDAY. THE GFS HAS THE CHARLOTTE
AREA GETTING NEAR A HALF INCH OF RAIN AND EVEN MORE NEAR MARSHVILLE.
SURFACE HIGH CENTERED OVER THE CAROLINAS AND VIRGINIA FOR FRIDAY ON
THE GFS. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY.
THE NEW ECMWF HAS THE COLD FRONT CROSSING OUR AREA AT 12Z TUESDAY
WITH THE RAIN GRADUALLY ENDING EAST OF CHARLOTTE AROUND SUNSET. THE
HIGH IS ALIGNED ROUGHLY THE SAME ON WEDNESDAY AS ON THE GFS WITH THE
FRONT LINGERING ACROSS FLORIDA. THE SHARP 500MB SHORTWAVE WILL BE
OVER THE MISSISSIPPI RIVER 00Z THURSDAY AND OVER WESTERN GEORGIA AT
12Z THURSDAY AND DEEPER THAN THE GFS AT THAT TIME. THE BIG
DIFFERENCE IN THE PRECIP SHIELD IS THAT LITTLE IF ANY PRECIP REACHES
OUR PIEDMONT AS THE SHORTWAVE PASSES ON THURSDAY ACCORDING TO THE
ECMWF. THE NEXT SYSTEM WILL BE CROSSING TENNESSEE BY 12Z SATURDAY AS
WELL BUT SOME PRECIP REACHING THE WESTERN MOUNTAINS EARLY SATURDAY.
TEMPERATURES NEAR NORMAL THROUGH THE MEDIUM RANGE.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...AVIATION FORECAST CONTINUES TO BE QUITE
TRICKY. IFR TO LIFR CIGS OBSERVED ATTM ACROSS MUCH OF THE FCST
AREA...PRIMARILY OVER THE ERN PIEDMONT. 1000-850MB LAYER DRIES A BIT
OVER THAT AREA OVER THE NEXT FEW HOURS WHICH COULD EITHER HELP
EVAPORATE FOG...OR PROMOTE CLEARING ABOVE THE FOG LAYER WHICH WOULD
ALLOW IT TO BECOME MORE DENSE. CIRRUS MOVING ACROSS THE REGION WILL
LIMIT CLOUD TOP COOLING WHICH IS ANOTHER LIMITING FACTOR FOR FOG/LOW
STRATUS DEVELOPMENT. AN EXAMINATION OF MODEL SOUNDINGS SHOWS THE SFC
SATURATED LAYER BECOMING THINNER WITH TIME TONIGHT. THIS DOES NOT
NECESSARILY MEAN OPERATIONAL CONDITIONS WILL IMPROVE AT AFFECTED
AIRPORTS BUT IT IMPLIES LESS PERSISTENT RESTRICTIONS. HAVE GENERALLY
MAINTAINED PRESENT CONDITIONS UNTIL JUST AFTER SUNRISE...WITH SOME
SLIGHT IMPROVEMENT LATE AS THE DRYING OCCURS ALOFT. ONCE THE
OVERNIGHT FOG/STRATUS LIFT IN THE MORNING SOME VFR CLOUDS WILL
REMAIN IN PLACE THROUGH THE DAY. GUIDANCE HINTS AT SOME
REDEVELOPMENT OF RESTRICTIONS NEAR THE END OF THE PERIOD...AFTER 00Z
SUN...BUT CONFIDENCE CURRENTLY LOW SO DO NOT WANT TO INCLUDE IN TAFS
YET.
OUTLOOK...VFR CONDITIONS ARE EXPECTED OVERALL THRU THE WEEKEND...BUT
PATCHY FOG AND STRATUS WILL BE POSSIBLE BOTH SUNDAY AND MONDAY
MORNINGS. A STRONG COLD FRONT WILL CROSS THE REGION MONDAY OR MONDAY
NIGHT...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS ALONG WITH GUSTY
WINDS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR NCZ035-036-
056-068-069-501>510.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1035 PM CST FRI DEC 7 2012
.DISCUSSION.../ISSUED AT 85 PM CST/
ACTIVE FORECAST IN THE SHORT TERM. WENT AHEAD AND ALLOWED THE WINTER
WEATHER ADVISORY EXPIRE ACROSS THE AREA WITH ONLY MINOR ADDITIONAL
ACCUMULATIONS EXPECTED THROUGH THE EVENING. ATMOSPHERE IS EXPECTED
TO GRADUALLY DRY FROM ALOFT RESULTING IN DENDRITIC LAYER BEING CUT
OFF BRINGING AN END TO THE SNOW. LOW LEVEL SATURATION IS EXPECTED TO
REMAIN ACROSS THE AREA AND FOG HAS STARTED TO DEVELOP IN THE
STAGNANT AIR IN CENTRAL SOUTH DAKOTA. ADDED PATCHY FOG THIS EVENING
ACROSS THE WESTERN CWA THIS EVENING...BUT AS SOUTHERLY FLOW STARTS
TO INCREASE EARLY SATURDAY MORNING...THIS MAY LIMIT THE AREAL
COVERAGE WEST OF THE JAMES. FURTHER TO THE EAST...MUCH GREATER
POTENTIAL FOR FOG AS STRATUS BUILDS DOWN FROM ALOFT IN LIGHT
EASTERLY FLOW. RAP HAS DEVELOPED FAIRLY LARGE AREA ALONG AND EAST OF
I-29 OF FOG...AND MAY HAVE TO INCREASE WORDING AND NIGHT CREW MAY
NEED TO CONSIDER DENSE FOG ADVISORY. UPDATE POSTED.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
WIDESPREAD IFR TO MVFR CEILINGS AND VISIBILITIES WILL PERSIST ACROSS
THE REGION THROUGH 06Z SUNDAY. SNOW WILL SPREAD IN FROM THE WEST
SATURDAY AFTERNOON AND EVENING AHEAD OF A LOW PRESSURE SYSTEM. THE
BEST CHANCE FOR SNOW ALONG WITH IFR CONDITIONS WILL BE NORTH OF 90
SATURDAY AFTERNOON AND EVENING.
&&
.PREV DISCUSSION.../ISSUED AT 333 PM CST/
SHORT WAVE ENERGY...WELL DELINEATED BY THE MID AND UPPER QG FORCING
MOVING ACROSS OUR NORTHERN ZONES...WILL EXIT OUR FORECAST AREA THIS
EVENING. LIGHT SNOW WILL LINGER THIS EVENING THROUGHOUT OUR EASTERN
ZONES AS THIS WAVE EXISTS. HOWEVER THE MESOSCALE DYNAMICS HAVE
LARGELY DISSIPATED. THEREFORE ONLY BROAD LIFT REMAINS...AND AN
ATMOSPHERE WHICH IS DRYING OUT ALOFT. THE WILD CARD TONIGHT IS CLOUD
COVER. MODEL HUMIDITY TIME SECTIONS STRONGLY SUGGEST THAT STRATUS
WILL LINGER IN OUR FORECAST AREA. AND IN AREAS WHERE IT WOULD HAPPEN
TO CLEAR OUT SOMEWHAT THIS EVENING...THE STRATUS IS LIKELY TO OOZE
BACK DOWN FROM THE NORTH. THEREFORE KEPT SKY COVER EITHER CLOUDY OR
MOSTLY CLOUDY WHICH SHOULD HOLD THE LOWS UP RELATIVELY SPEAKING. IF
PARTS OF THE FORECAST AREA WOULD HAPPEN TO CLEAR OUT...THEN LOWS
WILL CERTAINLY BE COLDER THAN FORECAST...ESPECIALLY OVER AREAS OF
NEW SNOW COVER. SOMETHING TO WATCH FOR. /MJF
RELATIVELY CONSISTENT FORECAST FROM THE MODELS FOR TOMORROW LEADS TO
SLIGHTLY ABOVE NORMAL CONFIDENCE. A WARM FRONT IN THE 800-650MB
LAYER WILL MOVE INTO THE AREA LATE SATURDAY MORNING...THEN MOVE INTO
THE EASTERN CWA BY TOMORROW EVENING. WHILE INSTABILITY IS NOT
IMPRESSIVE...THERE APPEARS TO BE ENOUGH TO SUPPORT A RELATIVELY FAST
MOVING BAND OF SNOWFALL DEVELOPMENT AS IT PASSES. EXPECT ABOUT AN
INCH OF POTENTIAL AS IT PASSES. WARMER AIR WILL SURGE NORTHWARD
DURING THE DAY AS LOW PRESSURE WRAPS UP TO THE NORTH AND WEST SO
WILL AIM FOR NEAR 40 ALONG THE MISSOURI RIVER VALLEY WITH LOWER 30S
IN THE FAR NORTHERN CWA. WITH THIS WARMER AIR SOME LIGHT RAIN WILL
BE POSSIBLE IN PARTS OF NORTHWEST IOWA BUT OVERALL THE MODELS ARE A
LITTLE COLDER THAN YESTERDAY WHICH SUPPORTS MORE SNOW VERSUS RAIN.
SATURDAY NIGHT INTO SUNDAY WILL SEE AN ARCTIC AIR MASS SURGE SOUTH
BEHIND THE EXITING LOW PRESSURE. UPPER LEVEL SUPPORT AS WELL AS A
LITTLE WEAK THETA E ADVECTION AND MID LEVEL FRONTAL FORCING WILL
ALLOW FOR THE CONTINUED THREAT FOR LIGHT SNOW SATURDAY NIGHT INTO
SUNDAY MORNING...MAINLY IN THE EASTERN CWA. AMOUNTS WILL BE LIMITED
SO NOT EXPECTING ANY HEADLINES AT THIS TIME. THE ONLY HEADLINER
POTENTIAL WILL BE WIND ADVISORY AS A STRONG PRESSURE GRADIENT AND 40
KNOT 925MB WIND COMBINE TO BRING THE POTENTIAL FOR 30 TO 40 MPH
WINDS ON SUNDAY. WHEN COMBINED WITH THE VERY COLD TEMPERATURES WIND
CHILLS OF ZERO TO TEN BELOW WILL BE LIKELY.
CLEARING SKIES AND A WEAK SHORT LIVED RIDGE OF HIGH PRESSURE WILL
MOVE THROUGH ON SUNDAY NIGHT...WITH SOUTHERLY FLOW DEVELOPING DURING
THE DAY MONDAY. LOWS AROUND ZERO MUCH OF THE AREA WITH 5 TO 10
ABOVE IN LOCATIONS WITH LITTLE OR NO SNOW COVER. HIGHS ON MONDAY
WILL MAINLY BE IN THE 20S SO A LITTLE BIT IN THE COLD SIDE.
IN THE LATTER PERIODS(TUE/FRI)...WEST NORTHWEST FLOW ALOFT WILL
GRADUALLY TRANSITION TO SOUTHWEST FLOW ALOFT. THIS WILL KEEP
TEMPERATURES AT OR BELOW NORMAL THROUGH THE PERIOD WITH LITTLE IN
THE WAY OF PRECIPITATION CHANCES. AT THIS TIME IT APPEARS THAT A JET
STREAK WILL MOVE THROUGH THE REGION BRINGING A SLIGHT WARM UP
TUESDAY INTO WEDNESDAY THEN COLDER AIR WILL AGAIN FILTER SOUTHWARD.
GENERALLY HIGHS IN THE 30S TUESDAY AND WEDNESDAY...A FEW 40S SOUTH
ON WEDNESDAY...THEN BACK INTO THE 20S THURSDAY AND FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1141 PM CST FRI DEC 7 2012
.UPDATE...
06Z AVIATION DISCUSSION BELOW. QUICK UPDATE THIS NIGHT TO ACCOUNT
FOR INCREASINGLY MOIST UPSLOPE CONDITIONS UNFOLDING ACROSS OUR
NERN COUNTIES BEHIND A SAGGING COLD FRONT. VISBYS ARE ALREADY AOB
5SM IN SWRN OKLAHOMA WHERE DEWPOINT DEPRESSIONS HAVE QUICKLY
NARROWED. RAP AND THE HRRR APPEAR CREDIBLE IN THIS COLD FRONT
DIPPING SWWD TO NEAR A TULIA TO GUTHRIE LINE BY 12Z...SO HAVE
UPDATED FOR MENTION OF AREAS OF FOG EAST OF THIS LINE ALONG WITH
STRATUS. CONTINUED RADIATIONAL COOLING IN ADVANCE OF HIGHER
DEWPOINTS BEHIND THE FRONT MAY FAVOR WIDESPREAD FOG AND PERHAPS
NECESSITATE A DENSE FOG ADVISORY IN THE COMING HOURS. WILL
MONITOR THIS SCENARIO CLOSELY.
&&
.AVIATION...
VFR AT LBB WITH MVFR CONDITIONS LIKELY DEVELOPING AT CDS AROUND
10Z. FRONTAL BOUNDARY HAS RECENTLY EDGED SOUTHWEST NEAR CDS AHEAD
OF MOIST E-NELY WINDS AND LIGHT FOG. SHORT-TERM MODELS SUGGEST
WIDESPREAD DENSE FOG AND LIFR STRATUS AT CDS AROUND 09Z...BUT AM
HEDGING MORE CONSERVATIVELY WITH MVFR VIS BEING PREDOMINANT WITH
TEMPO LIFR IN DENSE FOG. THIS FRONT SHOULD STALL SHORT OF LBB BY
12Z KEEPING VFR CONDITIONS INTACT...BUT WILL HAVE A HARD TIME
RETREATING. THIS SETUP FAVORS KEEPING CDS SUB-VFR THROUGH EARLY
AFTN UNDER STRATUS AND LIGHT SELY WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 29 65 26 39 14 / 0 0 0 10 30
TULIA 33 64 29 41 17 / 0 0 0 10 20
PLAINVIEW 33 65 29 42 19 / 0 0 0 10 20
LEVELLAND 30 68 32 45 19 / 0 0 0 10 30
LUBBOCK 31 68 33 45 20 / 0 0 0 10 20
DENVER CITY 35 69 35 48 21 / 0 0 0 10 20
BROWNFIELD 35 70 34 47 21 / 0 0 0 10 20
CHILDRESS 35 64 34 47 24 / 0 0 0 10 20
SPUR 36 68 38 48 22 / 0 0 0 0 20
ASPERMONT 37 72 38 52 26 / 0 0 0 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
440 AM EST MON DEC 10 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 355 AM EST MON DEC 10 2012
A WEAK WAVE MOVING THROUGH THE AREA TODAY COULD PROMPT A
FEW SNOWFLAKES ACROSS THE NORTHERN COUNTIES. TONIGHT HIGH PRESSURE
WILL BUILD INTO THE AREA AND BRING DRY WEATHER WHICH WILL LAST
THROUGH FRIDAY. BY FRIDAY NIGHT ANOTHER SYSTEM WILL APPROACH THE
AREA AND BRING CHANCES FOR RAIN THAT WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 355 AM EST MON DEC 10 2012
AT 8Z RADAR MOSAIC SHOWED ALL RAIN HAD MOVED SOUTHEAST OF THE AREA.
SURFACE ANALYSIS SHOWED SURFACE LOW CENTERED OVER LAKE ERIE WITH A
COLD FRONT STRETCHING SOUTHWEST THROUGH WESTERN OHIO AND CENTRAL
KENTUCKY AND TENNESSEE TO NORTHERN MISSISSIPPI. MODELS SHOW THE LOW
CONTINUING TO MOVE NORTHEAST THROUGH THE DAY WITH THE FRONT BEING
DRAGGED EAST AS WELL. DRY AIR WAS WORKING ITS WAY INTO CENTRAL
INDIANA. A COUPLE MODELS ARE SHOWING SOME OF THE RAIN MAKING ITS WAY
BACK NORTH INTO THE SOUTHERN COUNTIES BUT MAJORITY ARE
NOT...INCLUDING THE RAP WHICH SEEMS TO HAVE A GOOD HANDLE ON CURRENT
PRECIP AREA...SO IT LOOKS UNLIKELY THAT IT WOULD GET THIS FAR NORTH.
WILL JUST INCLUDE A SLIGHT CHANCE FOR RAIN IN THE FAR SOUTHEAST
THROUGH THE MORNING.
MODELS SHOW A WEAK UPPER WAVE MOVING THROUGH THE NORTH IN
THE AFTERNOON/EVENING. NOT A LOT OF MOISTURE TO WORK WITH BUT COULD
PROMPT SOME FLURRIES ACROSS THE NORTHERN HALF OR SO OF THE AREA.
WITH 850 MB WINDS OUT OF THE NORTH TO NORTHEAST BRIEFLY COULD
PROVIDE SOME LAKE ENHANCEMENT TO THESE FLURRIES AND SO INCLUDED A
SLIGHT CHANCE OF MEASURABLE SNOW IN THE FAR NORTH TO COVER THIS
POSSIBILITY. STILL LITTLE TO NO ACCUMULATION EXPECTED.
ALTHOUGH DRY AIR ADVECTS IN ALOFT TIME HEIGHTS SHOW LOW LEVELS
REMAINING SATURATED. COMBINING THAT WITH CURRENT SATELLITE TRENDS
AND LOW CLOUDS EXTENDING BACK INTO WESTERN IOWA AND MINNESOTA THINK
SKIES WILL REMAIN CLOUDY THROUGH TODAY AND TONIGHT. FOR TEMPERATURES
WENT A LITTLE COLDER THAN CONSENSUS WITH COLD ADVECTION AND CLOUDY
SKIES.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 355 AM EST MON DEC 10 2012
FORECAST FOCUS IS ON TEMPERATURES. MODELS IN GOOD AGREEMENT SO WILL
USE A CONSENSUS. TONIGHT AN UPPER WAVE WILL BE MAKING IT/S EXIT OF
THE AREA. WITH LAKE ENHANCEMENT STILL BRIEFLY AVAILABLE INCLUDED
SOME FLURRIES IN THE NORTHEAST AS IT LEAVES. AFTER THAT HIGH
PRESSURE BUILDS IN FOR THE REMAINDER OF THE SHORT TERM BRINGING WITH
IT CLEARING SKIES FROM ON TUESDAY AND THEN MOSTLY CLEAR THROUGH THE
SHORT TERM AND SLOWLY WARMING TEMPERATURES AFTER TUESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 305 AM EST MON DEC 10 2012
MAIN FOCUS TO THE EXTENDED WILL BE ON TIMING AND COVERAGE OF POPS
ACROSS CENTRAL INDIANA ASSOCIATED WITH A STRONG WEEKEND SYSTEM.
MODELS HAVE LARGE DIFFERENCES ON TIMING AND STRENGTH OF THE
AFOREMENTIONED STRONG UPPER AND SURFACE SYSTEMS...HOWEVER THE 00Z
ECMWF AND CANADIAN ARE THE CLOSEST WITH THE LATTER JUST A TOUCH
FASTER. BOTH WERE SHOWING NEGATIVELY TILTED UPPER TROUGHS AND SUB
1000 MILLIBAR SURFACE LOWS MOVING TO NEAR SOUTHERN LAKE MICHIGAN
LATE SATURDAY. REGARDLESS...ALL MODELS ARE SUGGESTING CHANCE POPS
ESPECIALLY WEST FRIDAY NIGHT WITH WIDESPREAD ACTIVITY ON SATURDAY
AND THEN LESSENING CHANCES SATURDAY NIGHT AND SUNDAY AS THE SYSTEM
LIFTS NORTHEAST INTO SOUTHEASTERN CANADA. REGIONAL INITIALIZATION
REFLECTS THIS WITH LIKELY POPS ON SATURDAY AND LESSER CHANCES FRIDAY
NIGHT AND SATURDAY NIGHT INTO SUNDAY. SO...WILL NOT MAKE ANY
CHANGES.
THE EXTENDED WILL START OFF WITH SURFACE HIGH PRESSURE ACROSS THE
SOUTHEASTERN STATES AND INCREASING SOUTHWEST FLOW ACROSS THE OHIO
VALLEY AHEAD OF THE AFOREMENTIONED WEATHER MAKER. THIS WILL ALLOW
FOR ABOVE NORMAL TEMPERATURES CLIMAXING ON SATURDAY IN THE UPPER 40S
NORTH AND LOWER 50S SOUTH. BEHIND THE FRONT...TEMPERATURES WILL BE
NEAR NORMAL. WILL ACCEPT REGIONAL INITIALIZATION TEMPERATURES
ESPECIALLY WITH THE MODEL DIFFERENCES IN PLAY.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAF ISSUANCE/...
ISSUED AT 440 AM EST MON DEC 10 2012
MVFR CEILINGS EXPECTED THROUGH MUCH OF THE TAF PERIOD IMPROVING TO
VFR AFTER 07Z TUESDAY. COULD ALSO SEE A FEW AFTERNOON FLURRIES AS A
WEAK UPPER WAVE MOVES THROUGH. OTHERWISE...NORTHWEST WINDS AT 10
KNOTS OR SO WILL DROP BELOW 10 KNOTS AFTER 00Z. WINDS AND MUCH DRIER
AIR WILL PREVENT ANY VISIBILITY RESTRICTIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....MK
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
356 AM EST MON DEC 10 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 355 AM EST MON DEC 10 2012
A WEAK WAVE MOVING THROUGH THE AREA TODAY COULD PROMPT A
FEW SNOWFLAKES ACROSS THE NORTHERN COUNTIES. TONIGHT HIGH PRESSURE
WILL BUILD INTO THE AREA AND BRING DRY WEATHER WHICH WILL LAST
THROUGH FRIDAY. BY FRIDAY NIGHT ANOTHER SYSTEM WILL APPROACH THE
AREA AND BRING CHANCES FOR RAIN THAT WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 355 AM EST MON DEC 10 2012
AT 8Z RADAR MOSAIC SHOWED ALL RAIN HAD MOVED SOUTHEAST OF THE AREA.
SURFACE ANALYSIS SHOWED SURFACE LOW CENTERED OVER LAKE ERIE WITH A
COLD FRONT STRETCHING SOUTHWEST THROUGH WESTERN OHIO AND CENTRAL
KENTUCKY AND TENNESSEE TO NORTHERN MISSISSIPPI. MODELS SHOW THE LOW
CONTINUING TO MOVE NORTHEAST THROUGH THE DAY WITH THE FRONT BEING
DRAGGED EAST AS WELL. DRY AIR WAS WORKING ITS WAY INTO CENTRAL
INDIANA. A COUPLE MODELS ARE SHOWING SOME OF THE RAIN MAKING ITS WAY
BACK NORTH INTO THE SOUTHERN COUNTIES BUT MAJORITY ARE
NOT...INCLUDING THE RAP WHICH SEEMS TO HAVE A GOOD HANDLE ON CURRENT
PRECIP AREA...SO IT LOOKS UNLIKELY THAT IT WOULD GET THIS FAR NORTH.
WILL JUST INCLUDE A SLIGHT CHANCE FOR RAIN IN THE FAR SOUTHEAST
THROUGH THE MORNING.
MODELS SHOW A WEAK UPPER WAVE MOVING THROUGH THE NORTH IN
THE AFTERNOON/EVENING. NOT A LOT OF MOISTURE TO WORK WITH BUT COULD
PROMPT SOME FLURRIES ACROSS THE NORTHERN HALF OR SO OF THE AREA.
WITH 850 MB WINDS OUT OF THE NORTH TO NORTHEAST BRIEFLY COULD
PROVIDE SOME LAKE ENHANCEMENT TO THESE FLURRIES AND SO INCLUDED A
SLIGHT CHANCE OF MEASURABLE SNOW IN THE FAR NORTH TO COVER THIS
POSSIBILITY. STILL LITTLE TO NO ACCUMULATION EXPECTED.
ALTHOUGH DRY AIR ADVECTS IN ALOFT TIME HEIGHTS SHOW LOW LEVELS
REMAINING SATURATED. COMBINING THAT WITH CURRENT SATELLITE TRENDS
AND LOW CLOUDS EXTENDING BACK INTO WESTERN IOWA AND MINNESOTA THINK
SKIES WILL REMAIN CLOUDY THROUGH TODAY AND TONIGHT. FOR TEMPERATURES
WENT A LITTLE COLDER THAN CONSENSUS WITH COLD ADVECTION AND CLOUDY
SKIES.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 355 AM EST MON DEC 10 2012
FORECAST FOCUS IS ON TEMPERATURES. MODELS IN GOOD AGREEMENT SO WILL
USE A CONSENSUS. TONIGHT AN UPPER WAVE WILL BE MAKING IT/S EXIT OF
THE AREA. WITH LAKE ENHANCEMENT STILL BRIEFLY AVAILABLE INCLUDED
SOME FLURRIES IN THE NORTHEAST AS IT LEAVES. AFTER THAT HIGH
PRESSURE BUILDS IN FOR THE REMAINDER OF THE SHORT TERM BRINGING WITH
IT CLEARING SKIES FROM ON TUESDAY AND THEN MOSTLY CLEAR THROUGH THE
SHORT TERM AND SLOWLY WARMING TEMPERATURES AFTER TUESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 305 AM EST MON DEC 10 2012
MAIN FOCUS TO THE EXTENDED WILL BE ON TIMING AND COVERAGE OF POPS
ACROSS CENTRAL INDIANA ASSOCIATED WITH A STRONG WEEKEND SYSTEM.
MODELS HAVE LARGE DIFFERENCES ON TIMING AND STRENGTH OF THE
AFOREMENTIONED STRONG UPPER AND SURFACE SYSTEMS...HOWEVER THE 00Z
ECMWF AND CANADIAN ARE THE CLOSEST WITH THE LATTER JUST A TOUCH
FASTER. BOTH WERE SHOWING NEGATIVELY TILTED UPPER TROUGHS AND SUB
1000 MILLIBAR SURFACE LOWS MOVING TO NEAR SOUTHERN LAKE MICHIGAN
LATE SATURDAY. REGARDLESS...ALL MODELS ARE SUGGESTING CHANCE POPS
ESPECIALLY WEST FRIDAY NIGHT WITH WIDESPREAD ACTIVITY ON SATURDAY
AND THEN LESSENING CHANCES SATURDAY NIGHT AND SUNDAY AS THE SYSTEM
LIFTS NORTHEAST INTO SOUTHEASTERN CANADA. REGIONAL INITIALIZATION
REFLECTS THIS WITH LIKELY POPS ON SATURDAY AND LESSER CHANCES FRIDAY
NIGHT AND SATURDAY NIGHT INTO SUNDAY. SO...WILL NOT MAKE ANY
CHANGES.
THE EXTENDED WILL START OFF WITH SURFACE HIGH PRESSURE ACROSS THE
SOUTHEASTERN STATES AND INCREASING SOUTHWEST FLOW ACROSS THE OHIO
VALLEY AHEAD OF THE AFOREMENTIONED WEATHER MAKER. THIS WILL ALLOW
FOR ABOVE NORMAL TEMPERATURES CLIMAXING ON SATURDAY IN THE UPPER 40S
NORTH AND LOWER 50S SOUTH. BEHIND THE FRONT...TEMPERATURES WILL BE
NEAR NORMAL. WILL ACCEPT REGIONAL INITIALIZATION TEMPERATURES
ESPECIALLY WITH THE MODEL DIFFERENCES IN PLAY.
&&
.AVIATION /DISCUSSION FOR THE 100900Z IND TAF UPDATE/...
ISSUED AT 320 AM EST MON DEC 10 2012
FLIGHT CATEGORY HAS IMPROVED TO MVFR AT IND WITH CEILINGS UP TO 12K
FEET. IT SHOULD REMAIN MOSTLY MVFR THROUGH THE REST OF THE TAF
PERIOD.
PREVIOUS DISCUSSION FOLLOWS...
WIDESPREAD IFR CEILINGS 006-008 AGL ACROSS THE AREA...HOWEVER
DRIER AIR ADVECTING IN BEHIND THE COLD FRONT HAS ALLOWED CEILINGS TO
IMPROVE INTO THE MVFR CATEGORY OVER ILLINOIS. THESE HIGHER CEILINGS
SHOULD CONTINUE TO ADVECT INTO THE AREA OVERNIGHT...WITH CEILINGS
IMPROVING INTO THE MVFR CATEGORY PRIOR TO SUNRISE ON MONDAY. THE
MVFR CEILINGS EXPECTED TO LINGER THROUGH MIDDAY MONDAY AT LEAST.
PRESSURE RISE MAX CURRENTLY MOVING INTO WESTERN INDIANA...SO SOME
SURFACE WIND GUST TO AROUND 18 KTS FROM 290-310 DEGREES POSSIBLE FOR
THE REST OF THE NIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....MK
AVIATION...JAS/MK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
249 AM MST MON DEC 10 2012
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
04Z WATER VAPOR IMAGERY INDICATED TROUGH AXIS CENTERED OVER THE
CWA WITH BROAD RIDGING ACROSS THE WEST COAST. RAP DYNAMIC TROPOPAUSE
ANALYSIS INDICATED SHORT WAVE TROUGH MOVING OVER MONTANA...BUT DID
NOT APPEAR TO BE MUCH OF A RESPONSE ON WV IMAGERY. AT THE
SFC...RIDGE AXIS WAS LOCATED ALONG A KITR TO KANW LINE WITH
TEMPERATURES ALREADY IN THE SINGLE DIGITS ACROSS THE AREA.
MAIN SHORT TERM CONCERNS WILL BE WIND CHILLS THIS MORNING FOLLOWED
BY HOW QUICKLY TEMPERATURES RECOVER THROUGH THE MIDDLE OF THE WEEK.
EARLY MORNING HOURS...TEMPS HAVE FALLEN TO SEVERAL DEGREES BELOW
ZERO ACROSS NORTHEAST CWA WITH WINDS AROUND 10 MPH CREATING WIND
CHILLS IN THE -15 TO -20 RANGE. ALTHOUGH SOME SLIGHT WARMING HAS
BEEN NOTED ACROSS EASTERN COLORADO IN RESPONSE TO CONTINUED WESTERLY
FLOW/WAA...WILL LIKELY BE SEVERAL HOURS BEFORE THAT HAS A MEANINGFUL
IMPACT ACROSS NORTHEAST CWA. ALTHOUGH WINDS ARE NOT STRONG...THINK
CURRENT TEMPS WARRANT A WIND CHILL ADVISORY FOR THE MORNING HOURS.
WHILE CONDITIONS HAVE ALREADY OCCURRED ACROSS EASTERN
COLORADO...AFOREMENTIONED WARMING TREND IN OBS LEADS ME TO THINK
THREAT NOT GREAT IN THIS AREA.
TODAY...WEAK SHORT WAVE TROUGH WILL APPROACH FROM THE NORTH THIS
MORNING...BUT WITH VERY STABLE CONDITIONS EXPECTED FROM NEAR TERM
MODELS AND 00Z OBSERVATIONS AM DOUBTFUL THAT THIS INITIAL TROUGH WILL
DO MORE THAN CREATE A FEW HIGH CLOUDS THROUGH THE MORNING HOURS.
MAIN ISSUE TODAY WILL BE THE GUSTY WINDS THIS AFTERNOON AND HOW
QUICKLY TDS RECOVER FROM INITIAL VERY LOW VALUES AS POTENTIAL EXISTS
FOR LOW END CRITICAL FIRE WEATHER CONDITIONS TODAY. WINDS WILL PICK
UP INTO THE 15 TO 25 MPH RANGE DURING THE AFTERNOON...BUT THINK TDS
WILL ACTUALLY RISE SEVERAL DEGREES WITH VERTICAL MIXING. CURRENT
THOUGHTS KEEP THE HIGHEST WINDS AND DRIEST HUMIDITIES NOT VERY
COLOCATED AND WITH POTENTIAL FOR RISING AFTERNOON TDS...DO NOT PLAN
ON ISSUING A RFW AT THE MOMENT.
TONIGHT-TOMORROW...1.5 PVU FIELDS INDICATE SEVERAL SMALL SCALE SHORT
WAVE TROUGHS MOVING THROUGH THE FLOW TONIGHT...WITH STRONGEST (AT
LEAST FROM A PV PERSPECTIVE) COMING THROUGH THE CWA ON TUESDAY. GFS
AND NAM DIFFER ON STABILITY PROFILES OVERNIGHT WITH GFS INDICATING A
POCKET OF NEAR NEUTRAL CONDITIONS ACROSS WESTERN CWA BETWEEN 0 AND
06Z. WHILE NAM IS SLIGHTLY MORE STABLE...POINT SOUNDINGS DO INDICATE
SNOW GROWTH ZONE NOT TO FAR ABOVE THE SURFACE WITH A PERIOD OF ASCENT
MAXIMIZED IN THIS AREA. DO NOT THINK LIFT WILL BE ENOUGH FOR
MEANINGFUL PRECIP...BUT A FLURRIE OR TWO DOES NOT LOOK UNREASONABLE.
DESPITE AN APPARENTLY STRONGER TROUGH ON TUESDAY...NEAR GROUND SNOW
GROWTH ZONE DISAPPEARS AND OVERALL PROFILES ARE MUCH MORE
STABLE...SO DO NOT EXPECT FLURRIES TO CARRY ON THROUGH THE DAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
TUESDAY NIGHT-WEDNESDAY NIGHT...QUIET WEATHER EXPECTED FOR THE
PERIOD AS SHORT WAVE RIDGING WILL BUILD OVER THE AREA AS FLOW
BECOMES MORE AMPLIFIED IN RESPONSE TO TROUGH DEVELOPING OVER WEST
COAST. THINK A RAPID WARM UP IS POSSIBLE...WITH TEMPS APPROACHING
UPPER 50S TO LOW 60S BY WEDNESDAY. AM A LITTLE CONCERNED THAT
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ON WEDNESDAY AS
DEWPOINTS WILL REMAIN FAIRLY LOW AND NOT UNHEARD OF FOR DEVELOPING
LEE TROUGH TO BRING GUSTY WINDS. RIGHT NOW...THINGS LOOK TOO
MARGINAL FOR POTENTIAL WATCH...BUT WILL KEEP AN EYE ON AS PERIOD
APPROACHES.
THURSDAY-MONDAY...
SW FLOW WILL BE IN PLACE THURSDAY AS DEEP TROUGH DEVELOPS OVER THE
WESTERN US...WHICH SHOULD KEEP CONDITIONS MILD AND DRY OVER THE CWA.
HIGHS SHOULD BE A LITTLE COOLER FROM THE HIGHS ON WED...HOWEVER MOST
LOCATIONS SHOULD STILL BE IN THE MID 50S.
OPERATIONAL GUIDANCE IS IN DECENT AGREEMENT ON GENERAL TIMING/TRACK
OF TROUGH AS IS MOVES FROM THE SW US AND ACROSS SOUTHERN KANSAS
FRIDAY THROUGH SATURDAY...WITH CLOSED CENTER MOVING ACROSS SOUTHERN
KS. THIS COULD PUT OUR EASTERN CWA NEAR POSSIBLE DEFORMATION
ZONE/HEAVY SNOW BAND FRIDAY NIGHT. GEFS ENSEMBLES STILL SHOWING
GREATER SPREAD WITH GEFS MEAN MUCH SLOWER AND LESS AMPLIFIED AS A
RESULT. THERE HASNT BE A LOT OF RUN TO RUN CONTINUITY THE LAST FEW
DAYS...SO A LOT CAN STILL CHANGE CONSIDERING THE TIME RANGE. BASED
ON CURRENT RUNS IT DOES APPEAR CHANCES FOR A WINTER STORM DEVELOPING
OVER PARTS OF KANSAS COULD BE INCREASING. FOR OUR CWA THE FAVORED
LOCATIONS WOULD BE ACROSS THE EAST WHERE LIGHT SNOW ACCUMULATIONS
ARE POSSIBLE. I DID INCREASE POPS TO 40 ACROSS THE EAST THIS
FORECAST CYCLE...WITH CONFIDENCE TOO LOW TO GO MUCH HIGHER.
THERE IS SIGNIFICANT SPREAD IN THE UPPER LEVEL PATTERN AFTER THIS
SYSTEM SHIFTS EAST. GEFS AND GFS ARE GENERALLY SHOWING A
WESTERLY/ZONAL PATTERN ...WHILE ECMWF IS TRYING TO SHOW A MUCH MORE
PROGRESSIVE/ACTIVE PATTERN. REGARDLESS OF SOLUTION IT DOES APPEAR
THE ACTIVE STORM TRACK IS FAVORING AREAS OUTSIDE OF OUR CWA...SO IM
KEEPING LATER PERIODS DRY FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1036 PM MST SUN DEC 9 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. LIGHT WEST WINDS
WILL INCREASE DURING THE MORNING AFTER THE SUN COMES UP AND BECOME
GUSTY UNTIL LATE IN THE AFTERNOON. EVEN THOUGH CEILINGS WILL BE
VFR...CEILINGS WILL BEGIN TO LOWER LATE IN THE AFTERNOON INTO THE
EVENING HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY UNTIL 8 AM MST /9 AM CST/ THIS MORNING FOR
KSZ001>003-013>015.
CO...NONE.
NE...WIND CHILL ADVISORY UNTIL 8 AM MST /9 AM CST/ THIS MORNING FOR
NEZ079>081.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/DR
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1147 PM CST SUN DEC 9 2012
...UPDATE TO AVIATION...
.DISCUSSION...
20Z WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL TROUGH FROM THE FOUR
CORNERS REGION INTO THE DAKOTAS. ONE SHORTWAVE WAS LIFTING
NORTHEAST INTO MN WITH ANOTHER SHORTWAVE OVER THE CO AND NM
ROCKIES. AT THE SURFACE...A VERY STRONG COLD FRONT HAS PUSHED
SOUTH INTO NORTH TX AND EAST INTO CENTRAL MO. AREA OBSERVATIONS
INDICATE STRONG COLD AND DRY AIR ADVECTION IS ONGOING. RADAR
TRENDS THROUGHOUT THE DAY HAVE SUPPORTED THE IDEA THAT THE DRY AIR
NEAR THE SURFACE IS TO MUCH FOR WEAK FRONTOGENESIS IN THE MID
LEVELS TO OVERCOME.
FOR TONIGHT AND MONDAY...MODELS SHOW LITTLE OR NO LARGE SCALE
FORCING THROUGH THE PERIOD WITH THE ONLY INDICATION OF FORCING FOR
PRECIP BEING WEAK MID LEVEL FRONTOGENESIS THROUGH THE EARLY EVENING.
GIVEN THE CONTINUED ADVECTION OF DRY AIR IN THE LOWER TROPOSPHERE...
THINK PRECIP CHANCES ARE PRETTY CLOSE TO NIL. BY MONDAY...THE COLD
SURFACE RIDGE OF HIGH PRESSURE WITH VERY DRY AIR IS EXPECTED TO
DOMINATE THE WEATHER AS THE SHORTWAVE OVER THE SOUTHERN ROCKIES
PASSES MAINLY TO THE SOUTH OF THE FORECAST AREA. THEREFORE THE
FORECAST WILL REMAIN DRY. ABOUT THE ONLY WEATHER CONCERN IS CLOUD
COVER OVERNIGHT. VISIBLE SATELLITE SHOWS AN AREA OF STRATOCU MOVING
SWIFTLY SOUTH ACROSS EASTERN NEB. THE RAP SHOWS THIS DECK OF LOW
CLOUDS HANGING IN ACROSS NORTHEAST AND EAST CENTRAL KS THROUGH MUCH
OF THE NIGHT...AND THE NAM AND GFS TO A LESSER EXTENT SUPPORT THE
IDEA. SO THINK SKIES WILL BE MOSTLY CLOUDY TONIGHT. BECAUSE OF THIS
HAVE KEPT LOWS A DEGREE OR TWO WARMER THAN THE MOS GUIDANCE ACROSS
EASTERN KS. ADDITIONALLY A STRONGLY MIXED BOUNDARY LAYER SHOULD HELP
KEEP LOWS FROM PLUMMETING. NORTH CENTRAL KS COULD SEE SINGLE DIGIT
LOWS WHERE SKIES SHOULD CLEAR OUT SOONER. WITH SUCH A COLD START TO
THE DAY...HIGHS ARE EXPECTED TO ONLY MAKE IT INTO THE LOWER AND MID
30S FOR MONDAY EVEN WITH MOSTLY SUNNY SKIES.
WOLTERS
MID WEEK PERIODS LOOKING RATHER BENIGN. SOME MID AND HIGH CLOUDS
SHOULD BE ALL THAT RESULTS FROM THE NEXT UPPER WAVE PASSING THROUGH
THE CENTRAL PLAINS MONDAY NIGHT INTO EARLY TUESDAY. LOW LEVEL FLOW
REMAINS MAINLY WESTERLY TUESDAY FOR WEAK WARM AIR ADVECTION...AND
WAA INCREASES INTO WEDNESDAY AND THURSDAY AS BROAD RIDGING OVERTAKES
THE CENTRAL AND EASTERN CONUS. THE DEGREE OF MIXING INTO THE WARM
AND DRY MID LEVELS IS THE MAIN QUESTION FOR HOW WARM HIGHS WILL GET.
BUMPED THEM UP A FEW DEGREES AT THIS POINT BUT FURTHER INCREASES MAY
BE NEEDED. SSW WINDS INCREASE FOR WEDNESDAY INTO THURSDAY AND
RELATIVE HUMIDITIES MAY DROP TO LEVELS OF SOME CONCERN FOR FIRE
WEATHER MAINLY ON WEDNESDAY.
MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT WITH WESTERN TROF AND
UPPER LOW IN THE SOUTHWEST CONUS ON THURSDAY...BUT DIFFERENCES
MAGNIFY QUICKLY INTO THE WEEKEND. THE 12Z ECMWF PUSHES THE LOW EAST
AHEAD OF THE NORTHERN TROF AND ALLOWS A LOW TO RE-CLOSE AND DEEPEN
RAPIDLY OVER THE CENTRAL PLAINS...WHILE THE 12Z GFS KEEPS THE
SOUTHERN LOW BEHIND THE NORTHERN TROF FOR A WEAKENING WAVE IN THE
PLAINS. MODERATE PRECIPITATION CHANCES REMAIN...CENTERED AROUND
FRIDAY NIGHT...WITH SOME OPPORTUNITY FOR CONVECTION IN THE MORE
AMPLIFIED SOLUTIONS AND MINOR CONCERN FOR WINTRY PRECIP AS THE EVENT
WINDS DOWN. TEMPS SHOULD RETURN TO NEAR MID-DECEMBER NORMALS FOR
SUNDAY.
65
&&
.AVIATION...
A VFR STRATUS BAND (CEILINGS OF 3,200 TO 3,500 FEET) WAS OVER KTOP
AND KFOE...THE CEILINGS DROP ABOUT 1,000 FEE ON THE TRAILING EDGE
OF THE STRATUS FROM KMHK TO KCNK. CEILINGS AT KTOP AND KFOE WILL
DROP TO MVFR FOR A FEW HOURS BETWEEN 6Z AND 8Z...THEN SKIES WILL
CLEAR AFTER 8Z. SKIES SHOULD CLEAR AT KMHK AFTER 7Z. NORTHWEST
WINDS WILL DIMINISH UNDER 10 KTS THROUGH THE DAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
432 AM EST MON DEC 10 2012
.SYNOPSIS...
A WARM FRONT LIFTS VERY SLOWLY NORTH THROUGH THE MID ATLANTIC THIS
MORNING. A COLD FRONT APPROACHES FROM THE WEST THROUGH THIS
EVENING...BEFORE PUSHING ACROSS THE AREA LATE TONIGHT INTO EARLY
TUESDAY. LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE FRONT
TUESDAY NIGHT AND TRACKS OFF THE COAST WEDNESDAY. HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS SHOWS LOW PRESSURE OVER EASTERN GREAT LAKES
THIS MORNING, WITH WEAK QUASI-STATIONARY FRONT STILL DRAPED OVER
INTERIOR EASTERN SHORE...ACROSS INTO SOUTH CENTRAL VA AND BACK
INTO WESTERN PA/E OHIO. VISIBILITIES HAVE BEGUN TO IMPROVE AS
EXPECTED ACROSS INTERIOR NC AND ALONG I-85 CORRIDOR. WILL BE
DROPPING DENSE FOG ADVISORY WITH MORNING PACKAGE ISSUANCE OVER
SOUTHERN PORTIONS OF THE AREA. DO EXPECT VISIBILITIES TO CONTINUE
TO IMPROVE W/CONTINUED WAA, BUT FOR NOW WILL HOLD ONTO MOST
LOCATIONS ALONG AND NORTH OF A FARMVILLE- RICHMOND- WALLOPS LINE.
LATEST SUBJECTIVE UPPER AIR ANALYSIS SHOWS POSITIVELY TILTED UPPER
TROUGH AXIS EXTENDING FROM THE UPPER MID WEST BACK INTO THE
CENTRAL HIGH PLAINS. BROAD, MOIST SW FLOW AHEAD OF THIS FEATURE
FROM THE SOUTHEASTERN CONUS UP INTO THE MID-ATLANTIC REGION. SOME
SHRAS NOTED ON REGIONAL RADAR MOSAIC IN ASSOCIATION WITH WEAK
SHORTWAVE TROUGH PUSHING ACROSS THE CAROLINA COASTAL PLAIN. MODELS
SEEM TO BE HAVING TROUBLE WITH THIS FEATURE, SO HAVE USED A BLEND
OF RUC AND SREF IN QUICKLY SCOOTING THIS WAVE OFFSHORE BY MID TO
LATE MORNING, WITH A FEW SHOWERS PUSHING INTO FAR EASTERN ZONES.
QPF LOOKING RATHER LIGHT...ON THE ORDER OF A FEW HUNDREDTHS TO A
TENTH OF AN INCH.
NORTHERN STREAM TROUGH LIFTS NORTH OF THE GREAT LAKES TODAY, AS
NEXT SOUTHERN PLAINS DAMPENS AS IT LIFTS FROM SOUTHERN PLAINS
TOWARDS THE OHIO VALLEY BY TONIGHT. AS THIS HAPPENS, SFC LOW OVER
THE EASTERN GRT LAKES WILL LIFT INTO QUEBEC WITH ATTENDANT SFC
COLD FRONT SWEEPING EASTWARD BY TONIGHT. AS IS USUALLY THE CASE,
MODELS APPEAR TOO AGGRESSIVE THIS MORNING IN PUSHING STALLED
FRONTAL BOUNDARY NORTH THIS MORNING, AND TRYING TO CLEAR OUT LOW
CLOUDS. WILL CONTINUE WITH PARTLY TO MOSTLY CLOUDY WORDING THROUGH
THE DAY, W/ HIGHS IN THE MID 60S TO LOW 70S, WITH A FEW MID 70S
POSSIBLE GIVEN PRESENT TEMPERATURES ALREADY IN THE L-M 60S ACROSS
SE VA/NE NC.
FORCING FOR ASCENT APPEARS RATHER ANEMIC THROUGH MUCH OF THE DAY
AND DESPITE MILD TEMPS AND LLVL MOISTURE, FORECAST SOUNDINGS
INDICATE DESTABILIZATION WILL BE DIFFICULT GIVEN SIGNIFICANT CLOUD
COVER THROUGH MOST OF THE DAY. THUS, EXPECT MOST OF THE DAY TO BE
DRY OVER THE AREA. DO INCREASE RAIN CHANCES OVER THE FAR NW BY THE
LATE AFTERNOON AS FRONT APPROACHES FROM THE WEST.
AS MENTIONED EARLIER, THE UPPER TROUGH WILL DAMPEN/WEAKEN AS IT
PUSHES ACROSS THE OHIO VALLEY INTO THE NORTHERN MID ATLANTIC
TONIGHT INTO EARLY TUESDAY, DRAGGING THE COLD FRONT ACROSS THE
CWA TONIGHT AND OFF THE COAST EARLY TUESDAY MORNING. HIGH END CHC
TO LIKELY POPS (50-60%) WILL BE MAINTAINED WITH THE FRONTAL
PASSAGE TONIGHT ACROSS THE WEST, ALTHOUGH QPF WILL BE RATHER
LIGHT. LOWS TONIGHT SHOULD BE IN THE MID 40S NW...TO MID 50S
SE...FOLLOWED BY HIGHS TUESDAY IN THE LOW 50S N AND W...TO LOW 60S
SE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE FRONT EVENTUALLY WILL BECOME STALLED SOUTH OF THE AREA BY
TUESDAY NIGHT AND WEDNESDAY. IN THE INTERIM, EXPECT CLEARING ON
TUESDAY WITH HIGH PRESSURE BUILDING IN FROM THE WEST. LINGERING
SHRAS ACROSS SE COASTAL PLAIN QUICKLY YIELD TO SEASONABLY COOL AND
DRY CONDITIONS BY AFTN. WINDS TURN AROUND TO THE NORTH AND REMAIN
RATHER LIGHT THROUGH THE DAY. HIGHS GENERALLY IN THE 50S UNDER A
PARTLY TO MOSTLY CLOUDY SKY
MODELS APPEAR IN A BIT MORE AGREEMENT WITH DEPICTING A WAVE OF
LOW PRESSURE THAT DEVELOPS ALONG THE STALLED BOUNDARY TO THE SOUTH
ON TUESDAY, BUT STILL SOME DISAGREEMENT WRT ORIENTATION OF PCPN
TUESDAY NIGHT AND WEDNESDAY. ECMWF KEEPS MUCH OF THIS ACTIVITY
WELL TO OUR SOUTH, WITH THE NAM BRINGING LIGHT PCPN AS FAR NORTH
AS RIC. GFS/SREF STILL APPEARS TO BE ACCEPTABLE MIDDLE GROUND
SOLUTION, BRINGING SOME LIGHT PCPN ACROS SOUTHERN TIER OF COUNTIES
LATE TUE-WED. CONTINUED INHERITED TREND WITH INCREASING CLOUDS
TUESDAY NIGHT/WED ACROSS THE SOUTHEAST, WITH RAIN CHCS FOR LATE
TUE INTO WED STILL LOOKING GOOD (LOW QPF ONCE AGAIN). LOW
TEMPERATURES TUESDAY NIGHT ARE FORECAST TO BE IN THE MID 30S
N...TO LOW TO MID 40S SE. HIGHS WEDNESDAY IN THE MID 40S TO LOW
50S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/... FNTL BNDRY/ASSOCD MSTR
SLO TO EXIT THE CST WED NGT. AFT THAT...HI PRES BUILDS INTO THE
MDATLC RGN FM THU THROUGH FRI...THEN WEAKENS INTO THE NEXT WKND.
UNCERTAINTY EXISTS NEXT SAT/SUN WRT PTNTL BKDR CDFNT ENTERING THE
RGN FM THE N...AND PSBL ARRIVAL OF LO PRES FM THE W.
LO POPS WED NGT...GIVING WAY TO DRY WX (AND POPS AOB 14%) THU INTO
SAT. WILL BRING A GRADUAL INCRS IN CLDNS AND POPS FM SAT THROUGH
SUN. TEMPS WILL AVG OUT NR SEASONABLE LVLS THROUGH THE PD.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
A WARM FRONT DRAPED ACROSS CTRL VA IS ALLOWING WIDESPREAD FOG
(VIS GENERALLY LESS THAN 1/2SM) AND VERY LOW CIGS TO PLAGUE THIS
AREA EARLY THIS MORNING. TAF SITES KRIC AND KPHF...AND TO A LESSER
EXTENT KSBY...WILL BE THE MOST SUSCEPTIBLE TO THESE CONDITIONS
THRU AT LEAST 10/1200-1300Z. AS THE WARM FRONT MOVES NORTH OF THE
REGION THIS MORNING...A DISTURBANCE ALONG THE NC COAST WILL MOVE
NORTH AND SPREAD LIGHT RAIN SHOWERS OVER NE NC...FAR SE VA...AND
THE MD/VA LOWER ERN SHORE MID-MORNING THRU EARLY AFTN BEFORE
MOVING NE AND AWAY FROM THE MID ATLANTIC COAST. SOME CLEARING...OR
AT LEAST HIGHER CIGS AND VIS...ARE ANTICIPATED DURING THE AFTN AS
THE REGION SITS WITHIN THE WARM SECTOR AHEAD OF AN APPROACHING
COLD FRONT TO THE WEST. EXPECT BREEZY SOUTH WINDS TO DEVELOP BY
EARLY AFTN AND PERSIST INTO THIS EVENING...BECOMING GUSTY AT TIMES
(15-20KT). THE COLD FRONT IS FORECAST TO CROSS THE AREA TONIGHT
INTO TUESDAY MORNING. THE BEST RAINFALL WILL OCCUR RIGHT ALONG THE
FRONT LATE THIS EVENING...GRADUALLY DIMINISHING IN INTENSITY
OVERNIGHT AS ITS ENERGY GETS SHEARED APART WHILE IT TRACKS TWD THE
COAST. CIGS ARE ESTIMATED TO BE 2-3KFT AND VIS SHOULD BE NO LOWER
THAN 3-4SM UNDER HEAVIER AREAS OF RAINFALL.
LINGERING PRECIP IS POSSIBLE ALONG THE IMMEDIATE MID ATLANTIC
COAST TUESDAY MORNING WITH CONDITIONS IMPROVING THROUGHOUT THE
DAY. A SECONDARY LOW PRESSURE SYSTEM WILL TRACK UP THE COAST AND
BRING STEADY STRATIFORM PRECIP MAINLY TO AREAS SE OF A LINE FROM
KSBY-KRIC-KDAN LATE TUESDAY NIGHT INTO WEDNESDAY. THIS SYSTEM HAS
THE POTENTIAL TO RAPIDLY DETERIORATE CIGS/VIS AT ALL TAF SITES
DURING THIS TIME.
&&
.MARINE...
A WARM FRONT WILL LIFT NORTH AS WARM FRONT AS A COLD FRONT
APPROACHES FROM THE WEST TODAY. S WINDS WILL GRADUALLY INCREASE AND
VEER TO THE SSW-SW THROUGH THE MORNING AND BECOME BREEZY/GUSTY BY
EARLY AFTN. SUSTAINED WINDS WILL AVERAGE 10-15 KT WITH GUSTS OF
15-20 KT OVER ALL AREA WATERS. THEREFORE...SCA FLAGS HAVE BEEN
RAISED FOR ERN VA RIVERS AND CURRITUCK SOUND BEGINNING AT NOON AND
ENDING AROUND MIDNIGHT. NRN COASTAL WATERS WILL SEE THEIR INCREASE
IN WIND SPEEDS LATE AFTN/EARLY EVENING WITH SUSTAINED 20 KT AND
GUSTS OF 25-30 KT AT TIMES. OVERALL...MAIN SUITE OF SCA HEADLINES
ISSUED ON SUNDAY REMAIN INTACT REGARDING TIMING...WIND
SPEEDS/GUSTS...AND WAVES/SEAS (3-4 FT BAY/4-5 FT OCEAN).
THE COLD FRONT CROSSES THE WATERS MONDAY NIGHT...FOLLOWED BY LLVL
SURGE AND MODERATE PROBABILITIES FOR SCA SPEEDS AS WINDS BECOME NNW
AFTER MIDNIGHT. CONDITIONS WILL BE SLOW TO IMPROVE DURING TUESDAY AS
THE FRONT STALLS JUST OFF THE COASTAL CAROLINAS AND WEAK HIGH
PRESSURE BUILDS IN THE NRN MID ATLANTIC REGION. EXPECT A PERIOD OF
NNE WINDS FROM TUE NIGHT INTO WED NIGHT AS A SECONDARY SFC LOW
PRESSURE DEVELOPS/TRACKS NE ALONG THE STALLED FRONT. TIGHT
TEMPERATURE DIFFERENCES WILL LIKELY RESULT IN A TIGHT PRESSURE
GRADIENT AND SPEEDS/WAVES/SEAS ARE ANTICIPATED TO INCREASE INTO SCA
THRESHOLDS...ESPECIALLY THE SRN PORTION OF THE BAY/OCEAN WATERS
TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE IS POISED TO RETURN LATE
IN THE WEEK WHICH WILL GREATLY IMPROVE MARINE WX CONDITIONS HEADING
INTO THE WEEKEND.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR MDZ021>025.
NC...NONE.
VA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ048-049-
060>064-067>078-083-085.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO NOON EST
TUESDAY FOR ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 AM EST
TUESDAY FOR ANZ633-635>637.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR ANZ632-634.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
TUESDAY FOR ANZ630-631-638.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...BMD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
413 AM EST MON DEC 10 2012
.SYNOPSIS...
A WARM FRONT LIFTS VERY SLOWLY NORTH THROUGH THE MID ATLANTIC THIS
MORNING. A COLD FRONT APPROACHES FROM THE WEST THROUGH THIS
EVENING...BEFORE PUSHING ACROSS THE AREA LATE TONIGHT INTO EARLY
TUESDAY. LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE FRONT
TUESDAY NIGHT AND TRACKS OFF THE COAST WEDNESDAY. HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS SHOWS LOW PRESSURE OVER EASTERN GREAT LAKES
THIS MORNING, WITH WEAK QUASI-STATIONARY FRONT STILL DRAPED OVER
INTERIOR EASTERN SHORE...ACROSS INTO SOUTH CENTRAL VA AND BACK
INTO WESTERN PA/E OHIO. VISIBILITIES HAVE BEGUN TO IMPROVE AS
EXPECTED ACROSS INTERIOR NC AND ALONG I-85 CORRIDOR. WILL BE
DROPPING DENSE FOG ADVISORY WITH MORNING PACKAGE ISSUANCE OVER
SOUTHERN PORTIONS OF THE AREA. DO EXPECT VISIBILITIES TO CONTINUE
TO IMPROVE W/CONTINUED WAA, BUT FOR NOW WILL HOLD ONTO MOST
LOCATIONS ALONG AND NORTH OF A FARMVILLE- RICHMOND- WALLOPS LINE.
LATEST SUBJECTIVE UPPER AIR ANALYSIS SHOWS POSITIVELY TILTED UPPER
TROUGH AXIS EXTENDING FROM THE UPPER MID WEST BACK INTO THE
CENTRAL HIGH PLAINS. BROAD, MOIST SW FLOW AHEAD OF THIS FEATURE
FROM THE SOUTHEASTERN CONUS UP INTO THE MID-ATLANTIC REGION. SOME
SHRAS NOTED ON REGIONAL RADAR MOSAIC IN ASSOCIATION WITH WEAK
SHORTWAVE TROUGH PUSHING ACROSS THE CAROLINA COASTAL PLAIN. MODELS
SEEM TO BE HAVING TROUBLE WITH THIS FEATURE, SO HAVE USED A BLEND
OF RUC AND SREF IN QUICKLY SCOOTING THIS WAVE OFFSHORE BY MID TO
LATE MORNING, WITH A FEW SHOWERS PUSHING INTO FAR EASTERN ZONES.
QPF LOOKING RATHER LIGHT...ON THE ORDER OF A FEW HUNDREDTHS TO A
TENTH OF AN INCH.
NORTHERN STREAM TROUGH LIFTS NORTH OF THE GREAT LAKES TODAY, AS
NEXT SOUTHERN PLAINS DAMPENS AS IT LIFTS FROM SOUTHERN PLAINS
TOWARDS THE OHIO VALLEY BY TONIGHT. AS THIS HAPPENS, SFC LOW OVER
THE EASTERN GRT LAKES WILL LIFT INTO QUEBEC WITH ATTENDANT SFC
COLD FRONT SWEEPING EASTWARD BY TONIGHT. AS IS USUALLY THE CASE,
MODELS APPEAR TOO AGGRESSIVE THIS MORNING IN PUSHING STALLED
FRONTAL BOUNDARY NORTH THIS MORNING, AND TRYING TO CLEAR OUT LOW
CLOUDS. WILL CONTINUE WITH PARTLY TO MOSTLY CLOUDY WORDING THROUGH
THE DAY, W/ HIGHS IN THE MID 60S TO LOW 70S, WITH A FEW MID 70S
POSSIBLE GIVEN PRESENT TEMPERATURES ALREADY IN THE L-M 60S ACROSS
SE VA/NE NC.
FORCING FOR ASCENT APPEARS RATHER ANEMIC THROUGH MUCH OF THE DAY
AND DESPITE MILD TEMPS AND LLVL MOISTURE, FORECAST SOUNDINGS
INDICATE DESTABILIZATION WILL BE DIFFICULT GIVEN SIGNIFICANT CLOUD
COVER THROUGH MOST OF THE DAY. THUS, EXPECT MOST OF THE DAY TO BE
DRY OVER THE AREA. DO INCREASE RAIN CHANCES OVER THE FAR NW BY THE
LATE AFTERNOON AS FRONT APPROACHES FROM THE WEST.
AS MENTIONED EARLIER, THE UPPER TROUGH WILL DAMPEN/WEAKEN AS IT
PUSHES ACROSS THE OHIO VALLEY INTO THE NORTHERN MID ATLANTIC
TONIGHT INTO EARLY TUESDAY, DRAGGING THE COLD FRONT ACROSS THE
CWA TONIGHT AND OFF THE COAST EARLY TUESDAY MORNING. HIGH END CHC
TO LIKELY POPS (50-60%) WILL BE MAINTAINED WITH THE FRONTAL
PASSAGE TONIGHT ACROSS THE WEST, ALTHOUGH QPF WILL BE RATHER
LIGHT. LOWS TONIGHT SHOULD BE IN THE MID 40S NW...TO MID 50S
SE...FOLLOWED BY HIGHS TUESDAY IN THE LOW 50S N AND W...TO LOW 60S
SE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
THE FRONT EVENTUALLY WILL BECOME STALLED SOUTH OF THE AREA BY TUESDAY
NIGHT AND WEDNESDAY. IN THE INTERIM, EXPECT CLEARING ON TUESDAY
WITH HIGH PRESSURE BUILDING IN FROM THE WEST.
MODELS APPEAR IN A BIT MORE AGREEMENT WITH DEPICTING A WAVE OF
LOW PRESSURE THAT DEVELOPS ALONG THE STALLED BOUNDARY TUESDAY, BUT
STILL SOME DISAGREEMENT WRT ORIENTATION OF PCPN. GFS/SREF STILL
APPEARS TO BE ACCEPTABLE MIDDLE GROUND SOLUTION, SO WILL REMAIN
CLOSE TO THAT SOLUTION. CONTINUED INCREASING CLOUDS TREND TUESDAY
NIGHT/WED WITH RAIN CHCS ACROSS SE ZONES STILL LOOKING GOOD. LOW
TEMPERATURES TUESDAY NIGHT ARE FORECAST TO BE IN THE MID 30S
N...TO LOW TO MID 40S SE...FOLLOWED BY HIGHS WEDNESDAY IN THE MID
40S TO LOW 50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
FNTL BNDRY/ASSOCD MSTR SLO TO EXIT THE CST WED NGT. AFT THAT...HI
PRES BUILDS INTO THE MDATLC RGN FM THU THROUGH FRI...THEN WEAKENS
INTO THE NEXT WKND. UNCERTAINTY EXISTS NEXT SAT/SUN WRT PTNTL BKDR
CDFNT ENTERING THE RGN FM THE N...AND PSBL ARRIVAL OF LO PRES FM THE
W.
LO POPS WED NGT...GIVING WAY TO DRY WX (AND POPS AOB 14%) THU INTO
SAT. WILL BRING A GRADUAL INCRS IN CLDNS AND POPS FM SAT THROUGH
SUN. TEMPS WILL AVG OUT NR SEASONABLE LVLS THROUGH THE PD.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
A WARM FRONT DRAPED ACROSS CTRL VA IS ALLOWING WIDESPREAD FOG
(VIS GENERALLY LESS THAN 1/2SM) AND VERY LOW CIGS TO PLAGUE THIS
AREA EARLY THIS MORNING. TAF SITES KRIC AND KPHF...AND TO A LESSER
EXTENT KSBY...WILL BE THE MOST SUSCEPTIBLE TO THESE CONDITIONS
THRU AT LEAST 10/1200-1300Z. AS THE WARM FRONT MOVES NORTH OF THE
REGION THIS MORNING...A DISTURBANCE ALONG THE NC COAST WILL MOVE
NORTH AND SPREAD LIGHT RAIN SHOWERS OVER NE NC...FAR SE VA...AND
THE MD/VA LOWER ERN SHORE MID-MORNING THRU EARLY AFTN BEFORE
MOVING NE AND AWAY FROM THE MID ATLANTIC COAST. SOME CLEARING...OR
AT LEAST HIGHER CIGS AND VIS...ARE ANTICIPATED DURING THE AFTN AS
THE REGION SITS WITHIN THE WARM SECTOR AHEAD OF AN APPROACHING
COLD FRONT TO THE WEST. EXPECT BREEZY SOUTH WINDS TO DEVELOP BY
EARLY AFTN AND PERSIST INTO THIS EVENING...BECOMING GUSTY AT TIMES
(15-20KT). THE COLD FRONT IS FORECAST TO CROSS THE AREA TONIGHT
INTO TUESDAY MORNING. THE BEST RAINFALL WILL OCCUR RIGHT ALONG THE
FRONT LATE THIS EVENING...GRADUALLY DIMINISHING IN INTENSITY
OVERNIGHT AS ITS ENERGY GETS SHEARED APART WHILE IT TRACKS TWD THE
COAST. CIGS ARE ESTIMATED TO BE 2-3KFT AND VIS SHOULD BE NO LOWER
THAN 3-4SM UNDER HEAVIER AREAS OF RAINFALL.
LINGERING PRECIP IS POSSIBLE ALONG THE IMMEDIATE MID ATLANTIC
COAST TUESDAY MORNING WITH CONDITIONS IMPROVING THROUGHOUT THE
DAY. A SECONDARY LOW PRESSURE SYSTEM WILL TRACK UP THE COAST AND
BRING STEADY STRATIFORM PRECIP MAINLY TO AREAS SE OF A LINE FROM
KSBY-KRIC-KDAN LATE TUESDAY NIGHT INTO WEDNESDAY. THIS SYSTEM HAS
THE POTENTIAL TO RAPIDLY DETERIORATE CIGS/VIS AT ALL TAF SITES
DURING THIS TIME.
&&
.MARINE...
FNTL BNDRY RMNS E-W ACRS THE CENTER OF THE CSTL WTRS THIS AFTN...W/
MNLY E WNDS N OF THE BNDRY...SSW S OF THE BNDRY. THE BNDRY WILL LIFT
BACK N AS WARM FRONT TNGT AS LO PRES TRACKS INTO THE LWR LAKES RGN.
WNDS BECOMING S...AND INCRSG (GRADUALLY) THROUGH THE OVRNGT...THOUGH
XPCD TO RMN JUST BLO SCA. AHD OF APPROACHING CDFNT FM THE W ON
MON...SSW WNDS AVG 10-20 KT...AND BY EVE XPCG SPEEDS ON THE BAY TO
BE AT MARGINAL SPDS FOR SCA. ALSO...SEAS ON THE OCN N OF CAPE
CHARLES XPCD TO GRADUALLY BUILD TO ABT 5 FT TWD EVE. CDFNT CROSSES
THE WTRS MON NGT...FOLLOWED BY LLVL SURGE AND MDT PROB FOR SCA SPDS
AS WNDS SWING TO NNW AFT MDNGT. CONDS TO SLOLY WANE DURG TUE AS FNT
STALLS JUST OF THE WTRS (INFO CSTL CAROLINAS) AND WK HI PRES BUILDS
IN THE NRN MDATLC RGN. PD OF NNE WNDS FM TUE NGT INTO WED NGT AS SFC
LO PRES DVLPS/TRACKS NE ALG THE STALLLED FNT. SPDS XPCD TO
INCRS...ESP SRN PORTION OF THE BAY/OCN WTRS TUE NGT INTO WED...ALG
W/ CORRESPONDING BUILDING WAVES/SEAS. BOTH 12Z/09 ECMWF/GFS AGREE
THAT HI PRES TO RETURN LT WK RESULTING IN BETTER MARINE WX CONDS
(HEADING INTO NEXT WKND).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR MDZ021>025.
NC...NONE.
VA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ048-049-
060>080-083>086-099-100.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO NOON EST
TUESDAY FOR ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR ANZ632-634.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
TUESDAY FOR ANZ630-631.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...ALB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1119 PM CST SUN DEC 9 2012
.UPDATE...
ISSUED AT 844 PM CST SUN DEC 9 2012
GOING FORECAST STILL LOOKS GOOD. SCT -SHRA HAS MOVED OUT OF THE
CWA AS THE COLD FRONT CONTINUES TO MOVE SOUTHEAST. BACK EDGE OF
LOW CLOUDS ARE MOVING INTO WESTERN CWA WITH A SECOND AREA OF LOW
CLOUDS MOVING IN QUICKLY BEHIND IT. RAP PROGS IS SHOWING ABUNDANT
AMOUNT OF LOW LEVEL MOISTURE STAYING IN THE AREA THROUGH MIDDAY
TOMORROW KEEPING SKIES MOSTLY CLOUDY THROUGH TOMORROW MORNING.
BRITT
&&
.SHORT TERM...
ISSUED AT 221 PM CST SUN DEC 9 2012
(TONIGHT)
PRIMARY CONCERN FOR TONIGHT WILL BE PRECIP CHANCES AND TEMPERATURES
BEHIND THE STRONG COLD FRONT THAT IS MOVING THROUGH THE REGION. THE
INITIAL WIND SHIFT IS ALREADY THROUGH THE NORTHWESTERN 2/3 OF THE
CWFA. WIND SHIFT SHOULD BE ALL THE WAY THROUGH OUR SOUTHEAST BORDER
WITH WFO PAH BY 00Z. UNTIL THEN...EXPECTING A CONTINUING THREAT FOR
THUNDERSTORMS ACROSS SOUTHEAST MO/SOUTHWEST IL. THUNDER THREAT
SHOULD DIMINISH AFTER FROPA AND ONLY EXPECT SHOWERS DURING THE
EVENING. WIND WILL BE INCREASING THROUGH THE EVENING BEHIND THE
FRONT AND GUSTS IN EXCESS OF 25KTS ARE LIKELY GIVEN THE STRONG
PRESSURE GRADIENT AHEAD OF THE 1035MB HIGH BUILDING ACROSS THE
PLAINS. WITH LOWS IN THE TEENS AND 20S IN THE COLD SECTOR THIS
MORNING ACROSS NEBRASKA...MOS FORECAST LOWS FOR TONIGHT IN THE 20S
LOOK VERY REASONABLE...AND WOULD NOT BE SURPRISED TO SEE IT GET
COLDER IN SOME SPOTS. WIND CHILL VALUES WILL BE A SLAP IN THE FACE
TOMORROW MORNING AFTER ALL THE MILD WEATHER WE`VE BEEN HAVING.
EXPECT READINGS IN THE SINGLE DIGITS TO MID TEENS.
CARNEY
&&
.LONG TERM...
ISSUED AT 221 PM CST SUN DEC 9 2012
(MONDAY AND MONDAY NIGHT)
EXPECT A COLD AND WINDY DAY WITH TEMPERATURES STRUGGLING TO RISE
BACK TO THE FREEZING MARK. IN FACT...LOOKING AT THE AIR MOVING IN
FROM THE NORTHWEST...MY FORECAST MAY STILL BE TOO WARM. WENT ON
COLDER SIDE OF GUIDANCE FOR MONDAY NIGHT AS RIDGE CENTER PROGRESSES
ACROSS THE CWA.
(TUESDAY THRU THURSDAY)
UPPER FLOW BECOMES MORE ZONAL DURING THIS PERIOD WITH A SHORTWAVE
PASSING TO OUR SOUTH ON WEDNESDAY. TEMPERATURES WILL MODERATE BACK
TO AND ABOVE NORMAL AS DRY WEATHER AND SOUTHWEST SURFACE WINDS ARE
ANTICIPATED.
(FRIDAY THRU SUNDAY)
UPPER FLOW WILL BECOME SOUTHWESTERLY BY WEEKS END AS A DEEP TROF
DIGS ACROSS THE WEST COAST. EVENTUALLY THIS TROF/LOW WILL CROSS THE
FOUR CORNERS REGION AND EJECT INTO THE PLAINS...WITH LEE
CYCLOGENESIS OCCURRING FRIDAY/FRIDAY NIGHT IN THE CENTRAL PLAINS.
HAVE IGNORED THE 12Z OPERATIONAL GFS AS IT DEAMPLIFIES THIS WAVE AS
IT MOVES EAST...TAKING THE SURFACE LOW DIRECTLY EAST WHICH SEEMS
UNREALISTIC AND INCONSISTENT WHEN COMPARED TO PREVIOUS RUNS AND
ENSEMBLE FORECASTS.
THE MORE CONSISTENT ECWMF MODEL SPINS THE SURFACE LOW UP ACROSS
SOUTHWEST KANSAS AND LIFTS IT NORTHEAST ACROSS NORTHWEST MISSOURI
...EASTERN IOWA...TOWARD THE WESTERN GREAT LAKES REGION. THIS PLACES
THE ENTIRE CWA IN THE WARM SECTOR OF THIS SYSTEM AND AM EXPECTING
ENOUGH RETURN FLOW FROM THE SOUTH FOR THUNDERSTORMS TO BE LIKELY
WITH THIS SYSTEM.
AIR BEHIND THIS SYSTEM APPEARS TO BE MORE PACIFIC...THAN
CANADIAN...SO ABOVE NORMAL TEMPERATURES SHOULD CONTINUE ON SUNDAY.
CVKING
&&
.AVIATION...
ISSUED AT 1045 PM CST SUN DEC 9 2012
COLD FRONT HAS MOVED WELL SE OF THE TAF SITES ALONG WITH
ACCOMPANYING SHOWERS. NWLY SFC WINDS...GUSTY AT TIMES WILL
CONTINUE AT THE TAF SITES DUE TO A TIGHT SFC PRESSURE GRADIENT
BETWEEN THE STRONG SFC RIDGE OVER THE PLAINS AND THE SFC LOW OVER
THE OHIO VALLEY REGION. THESE RELATIVELY STRONG AND GUSTY NWLY SFC
WINDS WILL CONTINUE ON MON...THEN DIMINISH MON EVNG AS THE SFC
RIDGE AXIS APPROACHES THE TAF SITES. GETTING SOME CLEAR AREAS OR
SLOTS IN THE LOW LEVEL CLOUD DECK BETWEEN STL AND COU WITH MORE
WIDESPREAD OVERCAST CLOUD DECK ACROSS NRN MO. ACTUAL CLEARING LINE
OF LOW LEVEL CLOUDS STILL BACK W ACROSS ERN PORTIONS OF NEBRASKA
AND CNTRL KANSAS. THERE MAY BE BRIEF PERIODS OF VFR CONDITIONS
LATE TGT AND MON MRNG FROM COU TO THE ST LOUIS METRO AREA...BUT
THE MAJORITY OF THE TIME AN MVFR CLOUD CEILNG SHOULD CONTINUE
AROUND 2000 FT IN UIN AND 2000-3000 FT FROM COU TO THE ST LOUIS
METRO AREA. THE CLOUD CEILING SHOULD SCATTER OUT BY 18Z MON IN
COU AND AROUND 21Z MON AT THE OTHER TAF SITES AS THE ENTIRE LOW
LEVEL CLOUD FIELD FINALLY ADVECTS E OF THE TAF SITES.
SPECIFICS FOR KSTL...THE SKY COVER HAS RECENTLY GONE SCATTERED...BUT
THIS SHOULD BE SHORT LIVED AS MORE LOW LEVEL CLOUDS HAVE DROPPED
SEWD INTO CNTRL MO WHICH SHOULD IMPACT STL LATE TGT. WILL KEEP AN
MVFR CIG FORECAST IN THE STL TAF AROUND 2000-3000 FT LATE TGT AND
MUCH OF MON AS THE SATELLITE LOOP SHOWS MORE MVFR CLOUD CIGS
DROPPING SEWD TOWARDS STL AND THE MODELS DEPICT HIGH RELATIVE
HUMIDITY VALUES AROUND 2000-4000 FT LATE TGT UNTIL EARLY MON AFTN.
THE MVFR CLOUD DECK SHOULD SCATTER OUT LATE MON AFTN...AND FINALLY
GO CLEAR BY MON EVNG...WHILE THE RELATIVELY STRONG AND GUSTY NWLY
SFC WIND DIMINISHES MON EVNG AS THE SFC PRESSURE GRADIENT
RELAXES...AND THEN BECOMES LIGHT LATE MON NGT.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
156 AM EST MON DEC 10 2012
.SYNOPSIS...
PERIODS OF RAIN CAN BE EXPECTED ACROSS THE AREA THROUGH MONDAY AS
A SLOW MOVING COLD FRONT TRACKS EAST ACROSS THE AREA. THE
PRECIPITATION COULD END AS A BRIEF PERIOD OF SNOW SHOWERS MONDAY
NIGHT AS COLD AIR MOVES IN. TUESDAY WILL BE MOSTLY DRY AND CHILLY
AS HIGH PRESSURE BUILDS ACROSS THE AREA. WARMER AND CONTINUED DRY
WEATHER CAN BE EXPECTED WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE...QUICK UPDATE TO RMV CATEGORICAL POPS ACRS NEPA
DROPPING THEM DOWN TO THE LKLY RANGE. MAIN SLUG OF RAIN IS RIDING
NORTHEASTWARD INTO WRN NY AT THIS TIME WITH ONLY SCATTERED SHOWERS
ACRS CNTRL PA. STRONGEST H8 WINDS APPEAR TO BE FOCUSED OVR THE WRN
ZONES FOR THE NEXT 3 HRS AND LIFT FM THIS WAA AREA AND STRONG
ISENTROPIC UPGLIDE. THUS, HV INCRSD QPF AMNTS ACRS WRN AND NRN
SXNS.
APPEARS AS THO THREAT FOR FRZG RAIN HAS ENDED WITH NO MESONETS
RMNG BLO FRZG IN THE CWA. EVEN ROAD TEMPS HV WARMED ABV FREEZING.
SLUG OF RAIN THAT INITIALLY MVD INTO THE CATSKILLS ACTUALLY WARMED
TEMPS, DRAGGING WARM AIR DOWN FM ALOFT. THUS, OUTSIDE OF ANY BRIDGES
OR OVERPASSES ACRS THE CATSKILLS AND MOHAWK VLY ROAD SFCS SHOULD
NOT BCM SLICK OVRNGT.
PREVIOUS DISCUSSIONS BELOW...
10 PM UPDATE...JUST TWEAKED GRIDS SOME. DECIDED TO WIND DOWN POPS
FOR A FEW HOURS BETWEEN FIRST SHRT WAVE PASSING BY AT PRESENT AND
THEN NEXT ONE WHICH IS MOVING TWD PA. PRECIPITATION ECHOES WINDING
DOWN ON KBGM RADAR AS THEY ARE BEGINNING TO INCREASE IN SRN PA ON
THE KCCX RADAR. SO WILL BRING POPS BACK UP WITH THE ARRIVAL OF
THIS NEXT WAVE AND PRECIP FROM PA LATE TONIGHT. AS FOR PRECIP
TYPE... KTYX RADAR DUAL POLAR PRODUCTS SUGGEST A MELTING LAYER
ARND 4800 FEET IN NRN ONEIDA COUNTY. SURFACE MESONETS SHOW
TEMPERATURES A LITTLE ABV FREEZING SUGGESTING JUST PLAIN RAIN UP
THERE. HAVE AN SPS THAT WILL EXPIRE AT 11 PM FOR POTENTIAL FOR
FZRA AT THE ONSET OF THE PRECIP. WILL LET THIS EXPIRE. NRN ONEIDA
WILL SEE RAIN THRU THE NIGHT AS TEMPS CLIMB WITH CONTINUED WARMING
ALOFT. ALSO MESONETS IN THE CATSKILLS SHOW TEMPS ABV FRZG. AS THE
TEMPERATURES AT 850 MB ROCKET UP TO +5C OR SO...TEMPS WILL CONT TO
SLOWLY WARM OVERNIGHT.
BIG CHANGE FOR MONDAY WAS TO DROP POPS TO CHC-SLGHT CHC IN THE AM
HOURS AS ALL CONVECTION ALLOWING MODELS AND OTHER HI RES MODELS
SHOW LITTLE PRECIP AT ALL UNTIL CD FRNT APPROACHES IN THE
AFTERNOON. SO WILL BEGIN THE DAY WITH JUST ISLD-SCT SHRA AT BEST...AND
RAMP UP POPS TO CAT IN THE AFTERNOON.
7 PM UPDATE...ISSUED A SPECIAL WEATHER STATEMENT FOR THE WESTERN
CATSKILLS AND NORTHERN ONEIDA COUNTY FOR A BRIEF PERIOD OF
FREEZING RAIN. RAIN WILL OVERSPREAD THE REGION QUICKLY BY 3-4Z AS
A STRONG SHOT OF LOW-LEVEL MOISTURE ADVECTION AND ISENTROPIC
LIFT/WAA RAPIDLY LEADS TO WIDESPREAD LIGHT RAINS OVER THE AREA. A
FEW HIGHER TERRAIN SPOTS IN THE CATSKILLS AND FAR NORTHEAST ONEIDA
COUNTY COULD BEGIN AS A PERIOD OF FREEZING RAIN AS TEMPERATURES
LIKELY ARE CLOSE TO FREEZING IN THESE AREAS. IT WILL BE VERY
SPOTTY SO NO FZRA ADVY. DUE TO THE STRONG ISENTROPIC LIFT/WARM AIR
ADVECTION...TEMPERATURES SOAR TO 3-7C AT 850 MB BY 6Z AS PER
GFS...WITH SIMILAR TEMPERATURES ON THE NAM...CMC...RAP...AND LOCAL
WRF. THIS WARMING SHUD ALLOW TEMPERATURES TO CLIMB TO THE MID TO
UPPER 30S OR EVEN LOW 40S OVERNIGHT AS THE RAIN FALLS.
FIRST SHOT OF RAIN LIKELY WILL MOVE QUICKLY THRU C NY AND NE PA BY
6-7Z WITH THE NEXT SHOT RAPIDLY APPROACHING ARND 9Z-10Z OR SO AS
ANOTHER LOW-LEVEL JET AND ASSOCIATED MOISTURE ADVECTION AND
ENHANCED ISENTROPIC LIFT APPROACHES. THE WATER VAPOR SATELLITE
IMAGERY SHOWS THESE TWO LOWER-LEVEL WAVES WELL IN THE UPPER LEVEL
MOIST PLUMES...ONE NORTH OF NY AND THE OTHER ACRS THE OH VLLY TO
MID ATLANTIC. THE MODELS HAVE TWO DISTINCT LOW-LEVEL JETS AT 850
MB WHICH ARE TIED TO EACH OF THESE SHORT WAVES. HENCE PRECIP
INCREASES AGAIN LATE TONIGHT WITH NEXT WAVE. .
THEN FOR MONDAY MORNING AFTER THE SECOND WAVE...I SEE A BREAK IN
THE PRECIPITATION BEFORE THE RAIN SHOWERS MOVE THRU THE REGION
ALONG A COLD FRONT WHICH SWINGS THRU IN THE AFTERNOON. THE HIGH
RES WRF ARW AND WRF NMM...LOCAL WRF...RAP AND NAM 4KM ALL SHOW
LITTLE PRECIP MONDAY AM WITH PRECIP INCREASING AGAIN IN THE PM. FOR
NOW DO NOT HAVE THUNDER IN GRIDS FOR MONDAY AFTERNOON...BUT NAM
AND RAP SHOWALTERS ARE SLIGHT NEGATIVE...LOCAL WRF AND GFS ARE
SLIGHTLY POSITIVE. THE HI RES CONVECTION ALLOWING MODELS ALL SHOW
SOME SORT OF LINE OF HEAVIER SHRA ALONG THE COLD FRONT MON PM. SO
I TRENDED POPS DOWNWARD MONDAY AM...THEN INCREASED THEM IN THE
AFTERNOON TO ACCOUNT FOR CD FRONTAL SHRA ACVTY. WILL PASS ON IDEA
OF POSSIBLE THUNDER TO MID SHIFT WHICH WILL HAVE THE NEW 00Z
GUIDC TO LOOK AT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
COLD FRONT APPROACHES THE AREA ON MONDAY. WITH SURFACE LOW
PRESSURE TRACKING UP THE ST LAWRENCE VALLEY OUR AREA WILL BE IN
THE WARM SECTOR MONDAY WITH STEADIER RAIN PULLING OFF TO THE NORTH
AND EAST FOR AWHILE MONDAY MORNING INTO THE AFTERNOON. BASED ON
THIS EXPECT RAIN TO TAPER TO SHOWERS ESPECIALLY OVER NORTHEAST PA.
TEMPERATURES WILL CLIMB WELL INTO THE 50S.
COLD FRONT CROSS THE AREA STARTING AROUND 18Z OVER STEUBEN
COUNTY... AND AROUND 00Z OVER NORTHEAST PA. THIS WILL BE
ACCOMPANIED BY AND FOLLOWED BY A PERIOD OF HEAVIER RAIN. THE RAIN
MAY CHANGE TO A PERIOD OF LIGHT SNOW OVER CENTRAL NY AFTER OOZ AS
WEAK WAVES OF LOW PRESSURE MOVING NORTHEAST ALONG THE FRONT MAY
KEEP THE PRECIPITATION GOING FOR AWHILE MONDAY EVENING IN THE COLD
AIR. TEMPERATURES BRIEFLY COOL TO AROUND -10 AT 850 MB WHICH WILL
BE ENOUGH FOR A BRIEF LAKE RESPONSE LATER MONDAY NIGHT NW FLOW AND
SOME SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO. OVERALL
ACCUMULATIONS OF SNOW MONDAY NIGHT SHOULD BE LESS THAN 2 INCHES.
HIGH PRESSURE MOVES ACROSS THE AREA ON TUESDAY WITH DRY WEATHER
AND SEASONABLY COLD TEMPERATURES. WARMING TREND BEGINS ON
WEDNESDAY AS THE HIGH MOVES OFF TO THE EAST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
2 AM UPDATE...
NO SIGNIFICANT CHANGES REQUIRED TO THE EXTENDED AS PREVIOUS FCST
REMAINS IN EXCELLENT SHAPE. A VERY BENIGN PERIOD EXPECTED THROUGH
LATE WEEK AS HIGH PRESSURE REMAINS IN CONTROL OF THE WX PATTERN.
WEAK UPPER RIDGING ALOFT COMBINED WITH THE RETURN OF SOUTHERLY
FLOW AHEAD OF NEXT WEEKEND/S STORM SYSTEM WILL ALLOW FOR ABOVE
AVERAGE TEMPS BOTH THU AND FRI WITH HIGHS TOPPING OUT IN THE
MIDDLE TO UPPER 40S. AFOREMENTIONED SYSTEM EXPECTED TO BEGIN
IMPACTING THE AREA ON SAT WITH SCATTERED RA SHWRS INCREASING BY
MID/LATE AFTERNOON. SOME DISAGREEMENT REMAINS BETWEEN THE GFS AND
THE ECMWF WITH THE LATTER SHOWING A SLOWER AND WARMER SOLUTION
TOWARDS THE END OF THE WEEKEND AS BLOCKING HIGH PRESSURE REMAINS
ENTRENCHED ACROSS EASTERN CANADA. THE GFS ON THE OTHER HAND
ADVERTISES MUCH COOLER AIR FILTERING IN BY SUN WITH LAKE EFFECT
SNOWS POTENTIALLY REDEVELOPING AS COLD AIR FLOWS OVER THE WARMER
WATER OF LAKE ONTARIO. FOR NOW...HAVE DECIDED TO LEAVE WELL ENOUGH
ALONE UNTIL MODEL AGREEMENT BECOME BETTER ESTABLISHED.
PREVIOUS LONG TERM DISCUSSION...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT THROUGH THE EXTENDED
INDICATING SURFACE HIGH PRESSURE WILL PROVIDE DRY AND MILD
CONDITIONS THROUGH FRIDAY. LATE IN THE PERIOD LOW PRES IS FORECAST
TO TRACK FROM THE MID WEST NORTHEAST INTO THE UPPER GREAT LAKES
THEN ACROSS EASTERN CANADA. THE ECMWF IS SLOWER AND FARTHER WEST
WITH THIS SYSTEM THAN THE GFS. WILL CONTINUE WITH CHC POPS
SATURDAY THROUGH SUNDAY WITH PRECIP TYPE A RAIN/SNOW MIX CHANGING
TO ALL RAIN BY SUNDAY AS TEMPS WARM INTO THE LOWER/MIDDLE 40S.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
WIDESPREAD MVFR AND IFR CONDITIONS EXPECTED THROUGH THE DAY TODAY AS
A SERIES OF UPPER DISTURBANCES AND APPROACHING COLD FRONT CONTINUE
TO IMPACT THE AREA. LATEST UPSTREAM RADAR TRENDS SHOWING PRECIP
ASSOCIATED WITH THE NEXT APPROACHING UPPER WAVE OF ENERGY RAPIDLY
APPROACHING THE REGION. THAT SAID...EXPECT -RA TO CONTINUE THROUGH THE
OVERNIGHT HRS AT ALL TERMINALS HOWEVER STRONG WIND FIELDS ALOFT
WILL ONLY PRODUCE LIMITED MVFR VSBY RESTRICTIONS. WE CURRENTLY
EXPECT CONTINUED IFR CIGS AT BOTH ITH AND BGM...WHERE BOTH SITES
WILL SEE CIGS BELOW ALTERNATE MINS. AT ELM...WE EXPECT CIGS TO
EVENTUALLY GO DOWN AFTER 08Z WHICH WILL RESIDE BELOW IFR
THRESHOLDS FOR THE AIRFIELD. ELSEWHERE...MOSTLY MVFR CIGS ARE
EXPECTED WITH HEIGHTS HANGING IN THE 1000-1500 FT RANGE. THE
OTHER MAIN IMPACT OVERNIGHT WILL BE STRONG WINDS ALOFT AND LIKELY
LLWS CONDITIONS AT BOTH ELM AND AVP WHERE CALM WINDS ALONG THE
SFC WILL RAPIDLY INCREASE WITH HEIGHT. WIND SHEAR CONCERNS WILL
COME TO AN END BY 15Z AT BOTH SITES AS STRONG LOW-LEVEL JET CORE
EXITS STAGE RIGHT.
BEYOND 12Z...A TEMPORARY LULL IS EXPECTED WITH ONLY SOME -DZ OR
-SHRA HANGING AROUND. AFTER 18Z...MORE PRONOUNCED RA ACTIVITY WILL
BEGIN MOVING INTO THE AREA AS NEXT UPPER WAVE AND SFC COLD FRONT
TRAVERSE THE REGION. BEYOND COLD FRONTAL PASSAGE...MUCH COOLER AIR
WILL BEGIN MOVING INTO THE REGION WHICH MAY LEAD TO RAIN MIXING
WITH SNOW AFTER 00Z THIS EVENING.
OUTLOOK...
TUE...PATCHY MVFR...MAINLY ACRS CNTRL NY.
TUE NGT-FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...DJN/PVN
SHORT TERM...MSE
LONG TERM...CMG/RRM
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1254 AM EST MON DEC 10 2012
.SYNOPSIS...
PERIODS OF RAIN CAN BE EXPECTED ACROSS THE AREA THROUGH MONDAY AS
A SLOW MOVING COLD FRONT TRACKS EAST ACROSS THE AREA. THE
PRECIPITATION COULD END AS A BRIEF PERIOD OF SNOW SHOWERS MONDAY
NIGHT AS COLD AIR MOVES IN. TUESDAY WILL BE MOSTLY DRY AND CHILLY
AS HIGH PRESSURE BUILDS ACROSS THE AREA. WARMER AND CONTINUED DRY
WEATHER CAN BE EXPECTED WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE...QUICK UPDATE TO RMV CATEGORICAL POPS ACRS NEPA
DROPPING THEM DOWN TO THE LKLY RANGE. MAIN SLUG OF RAIN IS RIDING
NORTHEASTWARD INTO WRN NY AT THIS TIME WITH ONLY SCATTERED SHOWERS
ACRS CNTRL PA. STRONGEST H8 WINDS APPEAR TO BE FOCUSED OVR THE WRN
ZONES FOR THE NEXT 3 HRS AND LIFT FM THIS WAA AREA AND STRONG
ISENTROPIC UPGLIDE. THUS, HV INCRSD QPF AMNTS ACRS WRN AND NRN
SXNS.
APPEARS AS THO THREAT FOR FRZG RAIN HAS ENDED WITH NO MESONETS
RMNG BLO FRZG IN THE CWA. EVEN ROAD TEMPS HV WARMED ABV FREEZING.
SLUG OF RAIN THAT INITIALLY MVD INTO THE CATSKILLS ACTUALLY WARMED
TEMPS, DRAGGING WARM AIR DOWN FM ALOFT. THUS, OUTSIDE OF ANY BRIDGES
OR OVERPASSES ACRS THE CATSKILLS AND MOHAWK VLY ROAD SFCS SHOULD
NOT BCM SLICK OVRNGT.
PREVIOUS DISCUSSIONS BELOW...
10 PM UPDATE...JUST TWEAKED GRIDS SOME. DECIDED TO WIND DOWN POPS
FOR A FEW HOURS BETWEEN FIRST SHRT WAVE PASSING BY AT PRESENT AND
THEN NEXT ONE WHICH IS MOVING TWD PA. PRECIPITATION ECHOES WINDING
DOWN ON KBGM RADAR AS THEY ARE BEGINNING TO INCREASE IN SRN PA ON
THE KCCX RADAR. SO WILL BRING POPS BACK UP WITH THE ARRIVAL OF
THIS NEXT WAVE AND PRECIP FROM PA LATE TONIGHT. AS FOR PRECIP
TYPE... KTYX RADAR DUAL POLAR PRODUCTS SUGGEST A MELTING LAYER
ARND 4800 FEET IN NRN ONEIDA COUNTY. SURFACE MESONETS SHOW
TEMPERATURES A LITTLE ABV FREEZING SUGGESTING JUST PLAIN RAIN UP
THERE. HAVE AN SPS THAT WILL EXPIRE AT 11 PM FOR POTENTIAL FOR
FZRA AT THE ONSET OF THE PRECIP. WILL LET THIS EXPIRE. NRN ONEIDA
WILL SEE RAIN THRU THE NIGHT AS TEMPS CLIMB WITH CONTINUED WARMING
ALOFT. ALSO MESONETS IN THE CATSKILLS SHOW TEMPS ABV FRZG. AS THE
TEMPERATURES AT 850 MB ROCKET UP TO +5C OR SO...TEMPS WILL CONT TO
SLOWLY WARM OVERNIGHT.
BIG CHANGE FOR MONDAY WAS TO DROP POPS TO CHC-SLGHT CHC IN THE AM
HOURS AS ALL CONVECTION ALLOWING MODELS AND OTHER HI RES MODELS
SHOW LITTLE PRECIP AT ALL UNTIL CD FRNT APPROACHES IN THE
AFTERNOON. SO WILL BEGIN THE DAY WITH JUST ISLD-SCT SHRA AT BEST...AND
RAMP UP POPS TO CAT IN THE AFTERNOON.
7 PM UPDATE...ISSUED A SPECIAL WEATHER STATEMENT FOR THE WESTERN
CATSKILLS AND NORTHERN ONEIDA COUNTY FOR A BRIEF PERIOD OF
FREEZING RAIN. RAIN WILL OVERSPREAD THE REGION QUICKLY BY 3-4Z AS
A STRONG SHOT OF LOW-LEVEL MOISTURE ADVECTION AND ISENTROPIC
LIFT/WAA RAPIDLY LEADS TO WIDESPREAD LIGHT RAINS OVER THE AREA. A
FEW HIGHER TERRAIN SPOTS IN THE CATSKILLS AND FAR NORTHEAST ONEIDA
COUNTY COULD BEGIN AS A PERIOD OF FREEZING RAIN AS TEMPERATURES
LIKELY ARE CLOSE TO FREEZING IN THESE AREAS. IT WILL BE VERY
SPOTTY SO NO FZRA ADVY. DUE TO THE STRONG ISENTROPIC LIFT/WARM AIR
ADVECTION...TEMPERATURES SOAR TO 3-7C AT 850 MB BY 6Z AS PER
GFS...WITH SIMILAR TEMPERATURES ON THE NAM...CMC...RAP...AND LOCAL
WRF. THIS WARMING SHUD ALLOW TEMPERATURES TO CLIMB TO THE MID TO
UPPER 30S OR EVEN LOW 40S OVERNIGHT AS THE RAIN FALLS.
FIRST SHOT OF RAIN LIKELY WILL MOVE QUICKLY THRU C NY AND NE PA BY
6-7Z WITH THE NEXT SHOT RAPIDLY APPROACHING ARND 9Z-10Z OR SO AS
ANOTHER LOW-LEVEL JET AND ASSOCIATED MOISTURE ADVECTION AND
ENHANCED ISENTROPIC LIFT APPROACHES. THE WATER VAPOR SATELLITE
IMAGERY SHOWS THESE TWO LOWER-LEVEL WAVES WELL IN THE UPPER LEVEL
MOIST PLUMES...ONE NORTH OF NY AND THE OTHER ACRS THE OH VLLY TO
MID ATLANTIC. THE MODELS HAVE TWO DISTINCT LOW-LEVEL JETS AT 850
MB WHICH ARE TIED TO EACH OF THESE SHORT WAVES. HENCE PRECIP
INCREASES AGAIN LATE TONIGHT WITH NEXT WAVE. .
THEN FOR MONDAY MORNING AFTER THE SECOND WAVE...I SEE A BREAK IN
THE PRECIPITATION BEFORE THE RAIN SHOWERS MOVE THRU THE REGION
ALONG A COLD FRONT WHICH SWINGS THRU IN THE AFTERNOON. THE HIGH
RES WRF ARW AND WRF NMM...LOCAL WRF...RAP AND NAM 4KM ALL SHOW
LITTLE PRECIP MONDAY AM WITH PRECIP INCREASING AGAIN IN THE PM. FOR
NOW DO NOT HAVE THUNDER IN GRIDS FOR MONDAY AFTERNOON...BUT NAM
AND RAP SHOWALTERS ARE SLIGHT NEGATIVE...LOCAL WRF AND GFS ARE
SLIGHTLY POSITIVE. THE HI RES CONVECTION ALLOWING MODELS ALL SHOW
SOME SORT OF LINE OF HEAVIER SHRA ALONG THE COLD FRONT MON PM. SO
I TRENDED POPS DOWNWARD MONDAY AM...THEN INCREASED THEM IN THE
AFTERNOON TO ACCOUNT FOR CD FRONTAL SHRA ACVTY. WILL PASS ON IDEA
OF POSSIBLE THUNDER TO MID SHIFT WHICH WILL HAVE THE NEW 00Z
GUIDC TO LOOK AT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
COLD FRONT APPROACHES THE AREA ON MONDAY. WITH SURFACE LOW
PRESSURE TRACKING UP THE ST LAWRENCE VALLEY OUR AREA WILL BE IN
THE WARM SECTOR MONDAY WITH STEADIER RAIN PULLING OFF TO THE NORTH
AND EAST FOR AWHILE MONDAY MORNING INTO THE AFTERNOON. BASED ON
THIS EXPECT RAIN TO TAPER TO SHOWERS ESPECIALLY OVER NORTHEAST PA.
TEMPERATURES WILL CLIMB WELL INTO THE 50S.
COLD FRONT CROSS THE AREA STARTING AROUND 18Z OVER STEUBEN
COUNTY... AND AROUND 00Z OVER NORTHEAST PA. THIS WILL BE
ACCOMPANIED BY AND FOLLOWED BY A PERIOD OF HEAVIER RAIN. THE RAIN
MAY CHANGE TO A PERIOD OF LIGHT SNOW OVER CENTRAL NY AFTER OOZ AS
WEAK WAVES OF LOW PRESSURE MOVING NORTHEAST ALONG THE FRONT MAY
KEEP THE PRECIPITATION GOING FOR AWHILE MONDAY EVENING IN THE COLD
AIR. TEMPERATURES BRIEFLY COOL TO AROUND -10 AT 850 MB WHICH WILL
BE ENOUGH FOR A BRIEF LAKE RESPONSE LATER MONDAY NIGHT NW FLOW AND
SOME SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO. OVERALL
ACCUMULATIONS OF SNOW MONDAY NIGHT SHOULD BE LESS THAN 2 INCHES.
HIGH PRESSURE MOVES ACROSS THE AREA ON TUESDAY WITH DRY WEATHER
AND SEASONABLY COLD TEMPERATURES. WARMING TREND BEGINS ON
WEDNESDAY AS THE HIGH MOVES OFF TO THE EAST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT THROUGH THE EXTENDED
INDICATING SURFACE HIGH PRESSURE WILL PROVIDE DRY AND MILD
CONDITIONS THROUGH FRIDAY. LATE IN THE PERIOD LOW PRES IS FORECAST
TO TRACK FROM THE MID WEST NORTHEAST INTO THE UPPER GREAT LAKES
THEN ACROSS EASTERN CANADA. THE ECMWF IS SLOWER AND FARTHER WEST
WITH THIS SYSTEM THAN THE GFS. WILL CONTINUE WITH CHC POPS
SATURDAY THROUGH SUNDAY WITH PRECIP TYPE A RAIN/SNOW MIX CHANGING
TO ALL RAIN BY SUNDAY AS TEMPS WARM INTO THE LOWER/MIDDLE 40S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
WIDESPREAD MVFR AND IFR CONDITIONS EXPECTED THROUGH THE DAY TODAY AS
A SERIES OF UPPER DISTURBANCES AND APPROACHING COLD FRONT CONTINUE
TO IMPACT THE AREA. LATEST UPSTREAM RADAR TRENDS SHOWING PRECIP
ASSOCIATED WITH THE NEXT APPROACHING UPPER WAVE OF ENERGY RAPIDLY
APPROACHING THE REGION. THAT SAID...EXPECT -RA TO CONTINUE THROUGH THE
OVERNIGHT HRS AT ALL TERMINALS HOWEVER STRONG WIND FIELDS ALOFT
WILL ONLY PRODUCE LIMITED MVFR VSBY RESTRICTIONS. WE CURRENTLY
EXPECT CONTINUED IFR CIGS AT BOTH ITH AND BGM...WHERE BOTH SITES
WILL SEE CIGS BELOW ALTERNATE MINS. AT ELM...WE EXPECT CIGS TO
EVENTUALLY GO DOWN AFTER 08Z WHICH WILL RESIDE BELOW IFR
THRESHOLDS FOR THE AIRFIELD. ELSEWHERE...MOSTLY MVFR CIGS ARE
EXPECTED WITH HEIGHTS HANGING IN THE 1000-1500 FT RANGE. THE
OTHER MAIN IMPACT OVERNIGHT WILL BE STRONG WINDS ALOFT AND LIKELY
LLWS CONDITIONS AT BOTH ELM AND AVP WHERE CALM WINDS ALONG THE
SFC WILL RAPIDLY INCREASE WITH HEIGHT. WIND SHEAR CONCERNS WILL
COME TO AN END BY 15Z AT BOTH SITES AS STRONG LOW-LEVEL JET CORE
EXITS STAGE RIGHT.
BEYOND 12Z...A TEMPORARY LULL IS EXPECTED WITH ONLY SOME -DZ OR
-SHRA HANGING AROUND. AFTER 18Z...MORE PRONOUNCED RA ACTIVITY WILL
BEGIN MOVING INTO THE AREA AS NEXT UPPER WAVE AND SFC COLD FRONT
TRAVERSE THE REGION. BEYOND COLD FRONTAL PASSAGE...MUCH COOLER AIR
WILL BEGIN MOVING INTO THE REGION WHICH MAY LEAD TO RAIN MIXING
WITH SNOW AFTER 00Z THIS EVENING.
OUTLOOK...
TUE...PATCHY MVFR...MAINLY ACRS CNTRL NY.
TUE NGT-FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...DJN/PVN
SHORT TERM...MSE
LONG TERM...RRM
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1243 AM EST MON DEC 10 2012
.SYNOPSIS...
PERIODS OF RAIN CAN BE EXPECTED ACROSS THE AREA THROUGH MONDAY AS
A SLOW MOVING COLD FRONT TRACKS EAST ACROSS THE AREA. THE
PRECIPITATION COULD END AS A BRIEF PERIOD OF SNOW SHOWERS MONDAY
NIGHT AS COLD AIR MOVES IN. TUESDAY WILL BE MOSTLY DRY AND CHILLY
AS HIGH PRESSURE BUILDS ACROSS THE AREA. WARMER AND CONTINUED DRY
WEATHER CAN BE EXPECTED WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE...QUICK UPDATE TO RMV CATEGORICAL POPS ACRS NEPA
DROPPING THEM DOWN TO THE LKLY RANGE. MAIN SLUG OF RAIN IS RIDING
NORTHEASTWARD INTO WRN NY AT THIS TIME WITH ONLY SCATTERED SHOWERS
ACRS CNTRL PA. STRONGEST H8 WINDS APPEAR TO BE FOCUSED OVR THE WRN
ZONES FOR THE NEXT 3 HRS AND LIFT FM THIS WAA AREA AND STRONG
ISENTROPIC UPGLIDE. THUS, HV INCRSD QPF AMNTS ACRS WRN AND NRN
SXNS.
APPEARS AS THO THREAT FOR FRZG RAIN HAS ENDED WITH NO MESONETS
RMNG BLO FRZG IN THE CWA. EVEN ROAD TEMPS HV WARMED ABV FREEZING.
SLUG OF RAIN THAT INITIALLY MVD INTO THE CATSKILLS ACTUALLY WARMED
TEMPS, DRAGGING WARM AIR DOWN FM ALOFT. THUS, OUTSIDE OF ANY BRIDGES
OR OVERPASSES ACRS THE CATSKILLS AND MOHAWK VLY ROAD SFCS SHOULD
NOT BCM SLICK OVRNGT.
PREVIOUS DISCUSSIONS BELOW...
10 PM UPDATE...JUST TWEAKED GRIDS SOME. DECIDED TO WIND DOWN POPS
FOR A FEW HOURS BETWEEN FIRST SHRT WAVE PASSING BY AT PRESENT AND
THEN NEXT ONE WHICH IS MOVING TWD PA. PRECIPITATION ECHOES WINDING
DOWN ON KBGM RADAR AS THEY ARE BEGINNING TO INCREASE IN SRN PA ON
THE KCCX RADAR. SO WILL BRING POPS BACK UP WITH THE ARRIVAL OF
THIS NEXT WAVE AND PRECIP FROM PA LATE TONIGHT. AS FOR PRECIP
TYPE... KTYX RADAR DUAL POLAR PRODUCTS SUGGEST A MELTING LAYER
ARND 4800 FEET IN NRN ONEIDA COUNTY. SURFACE MESONETS SHOW
TEMPERATURES A LITTLE ABV FREEZING SUGGESTING JUST PLAIN RAIN UP
THERE. HAVE AN SPS THAT WILL EXPIRE AT 11 PM FOR POTENTIAL FOR
FZRA AT THE ONSET OF THE PRECIP. WILL LET THIS EXPIRE. NRN ONEIDA
WILL SEE RAIN THRU THE NIGHT AS TEMPS CLIMB WITH CONTINUED WARMING
ALOFT. ALSO MESONETS IN THE CATSKILLS SHOW TEMPS ABV FRZG. AS THE
TEMPERATURES AT 850 MB ROCKET UP TO +5C OR SO...TEMPS WILL CONT TO
SLOWLY WARM OVERNIGHT.
BIG CHANGE FOR MONDAY WAS TO DROP POPS TO CHC-SLGHT CHC IN THE AM
HOURS AS ALL CONVECTION ALLOWING MODELS AND OTHER HI RES MODELS
SHOW LITTLE PRECIP AT ALL UNTIL CD FRNT APPROACHES IN THE
AFTERNOON. SO WILL BEGIN THE DAY WITH JUST ISLD-SCT SHRA AT BEST...AND
RAMP UP POPS TO CAT IN THE AFTERNOON.
7 PM UPDATE...ISSUED A SPECIAL WEATHER STATEMENT FOR THE WESTERN
CATSKILLS AND NORTHERN ONEIDA COUNTY FOR A BRIEF PERIOD OF
FREEZING RAIN. RAIN WILL OVERSPREAD THE REGION QUICKLY BY 3-4Z AS
A STRONG SHOT OF LOW-LEVEL MOISTURE ADVECTION AND ISENTROPIC
LIFT/WAA RAPIDLY LEADS TO WIDESPREAD LIGHT RAINS OVER THE AREA. A
FEW HIGHER TERRAIN SPOTS IN THE CATSKILLS AND FAR NORTHEAST ONEIDA
COUNTY COULD BEGIN AS A PERIOD OF FREEZING RAIN AS TEMPERATURES
LIKELY ARE CLOSE TO FREEZING IN THESE AREAS. IT WILL BE VERY
SPOTTY SO NO FZRA ADVY. DUE TO THE STRONG ISENTROPIC LIFT/WARM AIR
ADVECTION...TEMPERATURES SOAR TO 3-7C AT 850 MB BY 6Z AS PER
GFS...WITH SIMILAR TEMPERATURES ON THE NAM...CMC...RAP...AND LOCAL
WRF. THIS WARMING SHUD ALLOW TEMPERATURES TO CLIMB TO THE MID TO
UPPER 30S OR EVEN LOW 40S OVERNIGHT AS THE RAIN FALLS.
FIRST SHOT OF RAIN LIKELY WILL MOVE QUICKLY THRU C NY AND NE PA BY
6-7Z WITH THE NEXT SHOT RAPIDLY APPROACHING ARND 9Z-10Z OR SO AS
ANOTHER LOW-LEVEL JET AND ASSOCIATED MOISTURE ADVECTION AND
ENHANCED ISENTROPIC LIFT APPROACHES. THE WATER VAPOR SATELLITE
IMAGERY SHOWS THESE TWO LOWER-LEVEL WAVES WELL IN THE UPPER LEVEL
MOIST PLUMES...ONE NORTH OF NY AND THE OTHER ACRS THE OH VLLY TO
MID ATLANTIC. THE MODELS HAVE TWO DISTINCT LOW-LEVEL JETS AT 850
MB WHICH ARE TIED TO EACH OF THESE SHORT WAVES. HENCE PRECIP
INCREASES AGAIN LATE TONIGHT WITH NEXT WAVE. .
THEN FOR MONDAY MORNING AFTER THE SECOND WAVE...I SEE A BREAK IN
THE PRECIPITATION BEFORE THE RAIN SHOWERS MOVE THRU THE REGION
ALONG A COLD FRONT WHICH SWINGS THRU IN THE AFTERNOON. THE HIGH
RES WRF ARW AND WRF NMM...LOCAL WRF...RAP AND NAM 4KM ALL SHOW
LITTLE PRECIP MONDAY AM WITH PRECIP INCREASING AGAIN IN THE PM. FOR
NOW DO NOT HAVE THUNDER IN GRIDS FOR MONDAY AFTERNOON...BUT NAM
AND RAP SHOWALTERS ARE SLIGHT NEGATIVE...LOCAL WRF AND GFS ARE
SLIGHTLY POSITIVE. THE HI RES CONVECTION ALLOWING MODELS ALL SHOW
SOME SORT OF LINE OF HEAVIER SHRA ALONG THE COLD FRONT MON PM. SO
I TRENDED POPS DOWNWARD MONDAY AM...THEN INCREASED THEM IN THE
AFTERNOON TO ACCOUNT FOR CD FRONTL SHRA ACVTY. WILL PASS ON IDEA
OF POSSIBLE THUNDER TO MID SHIFT WHICH WILL HAVE THE NEW 00Z
GUIDC TO LOOK AT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
COLD FRONT APPROACHES THE AREA ON MONDAY. WITH SURFACE LOW
PRESSURE TRACKING UP THE ST LAWRENCE VALLEY OUR AREA WILL BE IN
THE WARM SECTOR MONDAY WITH STEADIER RAIN PULLING OFF TO THE NORTH
AND EAST FOR AWHILE MONDAY MORNING INTO THE AFTERNOON. BASED ON
THIS EXPECT RAIN TO TAPER TO SHOWERS ESPECIALLY OVER NORTHEAST PA.
TEMPERATURES WILL CLIMB WELL INTO THE 50S.
COLD FRONT CROSS THE AREA STARTING AROUND 18Z OVER STEUBEN
COUNTY... AND AROUND 00Z OVER NORTHEAST PA. THIS WILL BE
ACCOMPANIED BY AND FOLLOWED BY A PERIOD OF HEAVIER RAIN. THE RAIN
MAY CHANGE TO A PERIOD OF LIGHT SNOW OVER CENTRAL NY AFTER OOZ AS
WEAK WAVES OF LOW PRESSURE MOVING NORTHEAST ALONG THE FRONT MAY
KEEP THE PRECIPITATION GOING FOR AWHILE MONDAY EVENING IN THE COLD
AIR. TEMPERATURES BRIEFLY COOL TO AROUND -10 AT 850 MB WHICH WILL
BE ENOUGH FOR A BRIEF LAKE RESPONSE LATER MONDAY NIGHT NW FLOW AND
SOME SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO. OVERALL
ACCUMULATIONS OF SNOW MONDAY NIGHT SHOULD BE LESS THAN 2 INCHES.
HIGH PRESSURE MOVES ACROSS THE AREA ON TUESDAY WITH DRY WEATHER
AND SEASONABLY COLD TEMPERATURES. WARMING TREND BEGINS ON
WEDNESDAY AS THE HIGH MOVES OFF TO THE EAST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT THROUGH THE EXTENDED
INDICATING SURFACE HIGH PRESSURE WILL PROVIDE DRY AND MILD
CONDITIONS THROUGH FRIDAY. LATE IN THE PERIOD LOW PRES IS FORECAST
TO TRACK FROM THE MID WEST NORTHEAST INTO THE UPPER GREAT LAKES
THEN ACROSS EASTERN CANADA. THE ECMWF IS SLOWER AND FARTHER WEST
WITH THIS SYSTEM THAN THE GFS. WILL CONTINUE WITH CHC POPS
SATURDAY THROUGH SUNDAY WITH PRECIP TYPE A RAIN/SNOW MIX CHANGING
TO ALL RAIN BY SUNDAY AS TEMPS WARM INTO THE LOWER/MIDDLE 40S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
LOW PRESSURE WILL TRACK ACROSS THE LOWER GREAT LAKES TONIGHT...AND
UP THE ST. LAWRENCE RIVER VALLEY ON MONDAY. A WARM FRONT WILL MOVE
ACROSS CENTRAL NY AND NORTHEAST PA TONIGHT. AREAS OF RAIN WILL
SLIDE THROUGH THE REGION DURING THE NEXT 12-24 HOURS WITH IFR AND
OTHER FUEL ALTERNATE MINIMUM RESTRICTIONS TO CEILINGS. VISIBILITIES
SHOULD BE SLIGHTLY BETTER IN CATEGORY WITH FLUCTUATIONS BETWEEN
VFR-MVFR.
WINDS WILL BE PREDOMINANTLY E-SE 5-10 KTS OVERNIGHT BUT A STABLE
BOUNDARY LAYER WILL KEEP DEEP VALLEY FLOWS AT KAVP-KELM LIGHT
AND VARIABLE. A STRONG CORRIDOR OF S-SW FLOW IS EXPECTED TO
DEVELOP ALOFT THIS EVENING WHICH COULD POSE A LLWS PROBLEM
FOR THE LIGHTER SFC WIND STATIONS WITH TOP OF INVERSION WINDS
AROUND 40-45 KTS. ON MONDAY...SW WINDS DEVELOP WITH BETTER MIXING
AT 10-15 KTS WITH A LATE PERIOD WIND SHIFT TO THE WEST-NW
ASSOCIATED WITH COLD FRONTAL PASSAGE.
OUTLOOK...
MON EVNG...IFR/MVFR WITH PERIODS OF RAIN ENDING.
LATE MON NGT/TUE...PATCHY MVFR...MAINLY ACRS CNTRL NY.
TUE NGT-FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...DJN/PVN
SHORT TERM...MSE
LONG TERM...RRM
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
318 AM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY...CROSS THE MIDDLE
ATLANTIC REGION TONIGHT...AND STALL OFFSHORE THE SOUTHEAST COAST ON
TUESDAY. COASTAL LOW PRESSURE WILL THEN DEVELOP AND TRACK ALONG THE
OFFSHORE FRONT THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 930 PM SUNDAY...
WHILE THE FRONTAL ZONE WEST OF THE MOUNTAINS HAS TEMPORARILY LIFTED
NORTH INTO THE OH VALLEY AS A WARM FRONT THIS EVENING...A WEDGE-LIKE
AIRMASS IS LINGERING OVER VA...WITH THE SURFACE FRONT NEAR THE NC/VA
BORDER. NORTH OF THE FRONT...DENSE FOG HAS ALREADY SET IN. WARM
ADVECTION ATOP THE NOCTURNAL STABLE LAYER SHOULD STRENGTHEN THE
INVERSION...BUT THERE IS VERY LITTLE PRECIP HELPING TO FURTHER LOCK
IN THE AIRMASS. THE RAP SHOWS A SOUTHERN WIND PUSHING INTO VA
OVERNIGHT...BUT THIS MAY BE A LITTLE AGGRESSIVE. THUS..WITH THE
BOUNDARY SO CLOSE TOP THE CWA...HAVE ADDED PATCHY FOG OVERNIGHT FOR
THE FAR NORTHERN AREAS OF FORSYTH...GUILFORD AND PERSON COUNTIES.
SOUTH OF THE BOUNDARY...FAIRLY UNIFORM SOUTH-SOUTHWESTERLY LOW LEVEL
FLOW CONTINUES IN THE WARM SECTOR. THE 00Z KGSO AND KMHX RAOBS SHOW
ALL OF THE MOISTURE CONFINED BELOW 750MB WITH A WEAK CAP JUST
ABOVE. THE FEW SHOWERS THAT HAVE DEVELOPED THIS EVENING HAVE
STRUGGLED TO EXTEND ABOVE 11K FT AND HAVE NOT PRODUCED ANY LIGHTNING
DESPITE SOME WEAK CAPE JUST ABOVE THE CAP. FORCING ALOFT IS
DIFFICULT TO LOCATE IN THE MOIST SOUTHWESTERLY FLOW AHEAD OF THE
MAIN UPPER TROUGH...BUT REGIONAL SURFACE AND 850MB OBS SHOW A WEAK
WAVE NEAR SC/GA COASTAL AREAS. WHILE THIS WAVE IS FORECAST TO
WEAKEN FURTHER AS IT MOVES ALONG THE COAST...MOST OF THE FORECAST
MODELS SHOW A SLUG OF ISENTROPIC LIFT IN THE 295-305K LAYER MOVING
NORTH THROUGH THE COASTAL PLAIN AROUND 09Z. THE AVAILABLE CAMS SHOW
WHAT SHOULD BE SOME LOW TOPPED SHOWERS BRUSHING THE I-95
CORRIDOR...ESPECIALLY OVER THE NORTHERN COASTAL PLAIN. WILL HAVE A
30 POP IN THIS AREA AFTER 09Z...AND KEEP THE MENTION OF ISOLATED
SHOWERS ELSEWHERE.
TEMPS CURRENTLY IN THE UPPER 50S AND LOWER 60S WILL SHOULDN FALL
TOO MUCH MORE UNDER MOSTLY OVERCAST SKIES...SO WILL ONLY ADJUST LOWS
TO MATCH THE CURRENT TRENDS. LOWS 55-61. -BLS
MONDAY:
THERE IS GOOD AGREEMENT WITH THE TIMING OF THE COLD FRONT INTO
WESTERN NC LATE MONDAY AFTERNOON. THE LATE ARRIVAL OF THE SFC COLD
FRONT WILL KEEP THE ASSOCIATED MAIN BAND OF CONVECTION WEST OF THE
AREA UNTIL 21 TO 00Z. PRIOR TO THE ARRIVAL OF THIS BAND...ISOLATED
TO SCATTERED SHOWERS WILL BE POSSIBLE ACROSS CENTRAL NC WITHIN THE
40-50KT H8 LOW-LEVEL JET AND INCREASING RIGHT-ENTRANCE REGION
DYNAMICS. MODELS INDICATE ONLY MARGINAL INSTABILITY(200 TO 500
J/KG)...A LIKELY PRODUCT OF WIDESPREAD CLOUD COVER. GIVEN THE LACK
OF INSTABILITY AND THE SHORTWAVE DYNAMICS RACING OFF TO THE
NORTHEAST(GREAT LAKES)...EXPECT THUNDER TO BE AN EXCEPTION NOT THE
RULE. WILL PUT IN ISOLATED THUNDER IN THE FAR WESTERN ZONES ONLY.
TEMPERATURES WILL BE DEPENDENT ON CLOUD COVER AND PRECIP
COVERAGE...WITH HIGHS A TOUCH COOLER THAN PREVIOUSLY THOUGHT.
HIGHS IN THE UPPER 60S NW TO MID 70S SOUTHEAST WITH BREEZY SWLY
WINDS OF 15 T0 25 MPH.
A COLD FRONT WILL APPROACH AND CROSS THE REGION OVERNIGHT MONDAY
INTO TUESDAY. PRECIP CHANCES WILL RAMP UP NEAR SUNSET ON MONDAY
ACROSS THE WEST AND THEN MOVE EASTWARD THROUGH THE OVERNIGHT HOURS
AND INTO EARLY TUESDAY. IT SHOULD BE NOTED THAT MODELS CONTINUE TO
TREND DRIER FOR CENTRAL NC WITH THE PASSAGE OF THIS COLD FRONT. IN
FACT...MODELS INDICATE A LINE OF SHOWERS ALONG AND AHEAD OF THE
FRONT MOVING INTO THE WESTERN PIEDMONT BY SUNSET...THEN WEAKENING
SIGNIFICANTLY AS IT MOVES EASTWARD INTO THE MORE STABLE AIR OVER THE
PIEDMONT/COASTAL PLAIN. AS A RESULT...WILL MAINTAIN LIKELY POPS FOR
LATE MONDAY/MONDAY EVENING IN THE WEST...WITH ONLY CHANCE POPS
FURTHER EAST TROUGH EARLY TUESDAY. PRECIP SHOULD COME TO AN END
TUESDAY AFTERNOON AS THE FRONT MOVES EAST OF THE AREA. INSTABILITY
APPEARS TO BE MARGINAL (AT BEST) AS THE FRONT CROSSES THE AREA
MONDAY NIGHT...BUT CANNOT COMPLETELY RULE OUT AN ISOLATED
THUNDERSTORM OR TWO.
TEMPS MONDAY NIGHT AND TUESDAY WILL ULTIMATELY BE DETERMINED BY THE
TIMING OF THE FRONT AND ASSOCIATED PRECIP AND EVENTUAL CAA. WITH THE
CURRENT TIMING OF THE FRONT IN MIND...WILL SHOW MILD TEMPS MONDAY
NIGHT...GENERALLY IN THE 50S. HIGHS ON TUESDAY ARE EXPECTED TO BE IN
THE MID/UPPER 50S ACROSS THE NORTHWEST (DUE TO THE EARLIER FRONTAL
PASSAGE) TO THE LOW/MID 60S FURTHER SOUTH AND EAST. THESE HIGHS MAY
VERY WELL OCCUR IN THE MORNING AND THEN FALL THROUGHOUT THE DAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM MONDAY...
IN RESPONSE TO THE APPROACH AND AMPLIFICATION OF A POSITIVELY-TILTED
TROUGH ALOFT - ONE COMPRISED BY PHASED NORTHERN AND SOUTHERN STREAMS
DOWNSTREAM OF A RETROGRESSIVE AND FLOW-SPLITTING RIDGE OVER THE
EAST PACIFIC - THE LOW LEVEL FRONTAL FROM THE NEAR TERM WILL STALL
OFFSHORE THE SOUTHEAST COAST. A SERIES OF FRONTAL WAVES WILL
SUBSEQUENTLY DEVELOP AND MIGRATE NORTHEASTWARD ALONG THE FRONTAL
ZONE.
WHILE THE STRONGEST DEEP LAYER LIFT AND MOISTENING IS CONSEQUENTLY
FORECAST TO HOLD ALONG THE SURFACE FRONT OFFSHORE...SLOPED ASCENT
ACROSS THE FRONTAL ZONE AND ASSOCIATED ANAFRONTAL RAIN WILL OCCUR
WESTWARD ACROSS PORTIONS OF CENTRAL...AND EASTERN NC LATE TUE
NIGHT-WED. HAVE ACCORDINGLY RAISED POP TO LIKELY WITH A QUARTER TO
HALF IN OF RAIN ACROSS THE SOUTHERN AND CENTRAL COASTAL
PLAIN...TAPERING TO CHANCE OVER CENTRAL ZONES...AND AOB SLIGHT
CHANCE OVER THE FAR WESTERN PIEDMONT (INCLUDING THE TRIAD). THICKER
AND LOWER OVERCAST...AND RAIN...EAST VS. WEST SHOULD YIELD
RELATIVELY UNIFORM TEMPERATURES IN THE UPPER 40S TO AROUND 50
DEGREES WEDNESDAY...AFTER CAA-DRIVEN BUT CLOUD-TEMPERED LOWS IN THE
UPPER 30S TO LOWER-MIDDLE 40S. WEST TO EAST CLEARING IN STRONG
SUBSIDENCE BEHIND THE TROUGH ALOFT...AND THE ASSOCIATED EASTWARD
MIGRATION OF MODIFIED ARCTIC HIGH PRESSURE THAT CONSISTS OF SUB-ZERO
TEMPERATURES OVER THE NORTHERN PLAINS THIS MORNING...SHOULD PROMOTE
EXCELLENT RADIATIONAL COOLING CONDITIONS...PARTICULARLY AWAY FROM A
LINGERING MSLP GRADIENT OVER THE COASTAL PLAIN. A TWO CATEGORY
REDUCTION TO WED NIGHT LOWS WERE WARRANTED...GIVEN 12Z PROJECTED
LOW LEVEL THICKNESS VALUES IN THE 1305 METER RANGE AND THE
AFOREMENTIONED EXCELLENT RADIATIONAL COOLING - LOWER-MIDDLE 20S WEST
TO AROUND FREEZING SOUTHEAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 315 AM MONDAY...
THE MODIFIED ARCTIC HIGH WILL UNDERGO FURTHER MODIFICATION AS IT
REMAINS OVERHEAD THROUGH THE END OF THE WORK WEEK...BEFORE SHIFTING
OFFSHORE AND YIELDING A MORE RAPIDLY MODERATING SOUTHERLY RETURN
FLOW FOR THE START OF THE WEEKEND. MEDIUM RANGE GUIDANCE IS THEN IN
GENERAL AGREEMENT...THE FASTER 00Z/10TH GFS NOTWITHSTANDING...THAT
THE NEXT FRONTAL SYSTEM WILL AFFECT OUR REGION WITH A CHANCE OF
SHOWERS SUNDAY INTO SUNDAY NIGHT. THE TREND TOWARD COOLER LOWS FROM
THE SHORT TERM WILL CONTINUE WITH EXCELLENT RADIATIONAL COOLING
WITHIN THE SURFACE RIDGE AXIS THU NIGHT (MIDDLE-UPPER 20S)...
CONTRASTED BY MODERATING TEMPS INTO THE UPPER 50S TO LOWER-MIDDLE
60S FOR HIGHS BY THE WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 145 AM MONDAY...
24-HR TAF PERIOD:
CONFIDENCE IS HIGHER THAN PREVIOUS NIGHTS THAT IFR/LIFR CEILINGS
WILL DEVELOP BETWEEN 06-12Z IN ASSOCIATION WITH AN INCREASINGLY
MOIST LOW-LEVEL SOUTHERLY FLOW...THOUGH SOME UNCERTAINTY PERSISTS...
MORE-SO AT THE EASTERN TERMINALS WHERE IT IS POSSIBLE THAT CEILINGS
AND VISBYS BOUNCE AROUND MORE...OR DO NOT FALL BELOW THE MVFR
CATEGORY. REGARDLESS...EXPECT CEILINGS AND VISBYS TO IMPROVE TO MVFR
BETWEEN 12-15Z AS SOUTHERLY FLOW/MIXING STRENGTHEN IN ADVANCE OF A
COLD FRONT APPROACHING THE MOUNTAINS FROM THE WEST...WITH MVFR OR
VFR CEILINGS DURING THE AFTERNOON. EXPECT SOUTHWESTERLY WINDS TO
BECOME SUSTAINED AT 10-15 KT WITH GUSTS TO 20 KT BY 15Z... FURTHER
INCREASING TO 15-20 KT WITH GUSTS UP TO 30 KT POSSIBLE DURING THE
AFTERNOON. SOUTHWESTERLY WINDS WILL WEAKEN AFTER SUNSET AS THE FRONT
PUSHES INTO THE FOOTHILLS...VEERING TO THE NW/NNW AT 10-15 KT AT
FROPA...WHICH IS ANTICIPATED ~06Z TUE AT INT/GSO...~09Z AT RDU...AND
09-12Z AT FAY/RWI. AT THIS TIME...DO NOT EXPECT MUCH IN THE WAY OF
PRECIPITATION WITH THE FRONT...THOUGH SHOWER ACTIVITY AND LOCALLY
REDUCED CEILINGS WILL BE POSSIBLE BETWEEN 00-12Z TUE AT ALL TAF
SITES.
LOOKING AHEAD:
A PERIOD OF VFR CONDITIONS IS EXPECTED IN THE WAKE OF THE FRONTAL
PASSAGE DURING THE DAY TUE...THOUGH MVFR CEILINGS MAY PERSIST AT THE
FAY/RWI TERMINALS. THE FRONT WILL STALL JUST OFFSHORE THE CAROLINA
COAST TUE NIGHT. EXPECT INCREASING CHANCES FOR RAIN AND CEILINGS
DETERIORATING TO IFR/LIFR AT THE RDU/FAY/RWI TERMINALS AND AT LEAST
MVFR/IFR AT THE INT/GSO TERMINALS BETWEEN 00-12Z WED AS A WAVE OF
LOW PRESSURE DEVELOPS ALONG THE STALLED FRONT. SUB-VFR CEILINGS ARE
EXPECTED TO PERSIST THROUGH THE DAY WED...WITH A RETURN TO DRY/VFR
CONDITIONS WED NIGHT THROUGH THE REMAINDER OF THE WEEK. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...CBL/BLS
SHORT TERM...MWS
LONG TERM....MWS
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 AM EST MON DEC 10 2012
.SYNOPSIS...
A WARM SOUTHERLY FLOW WILL PREVAIL OVER THE CAROLINAS TODAY...IN
ADVANCE OF A COLD FRONT APPROACHING THE MOUNTAINS FROM THE WEST. THE
COLD FRONT WILL CROSS CENTRAL NORTH CAROLINA EARLY TUESDAY
MORNING...THEN SLOW DOWN AND STALL JUST OFFSHORE THE CAROLINA COAST.
A WAVE OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE STALLED
FRONT TUESDAY NIGHT.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 930 PM SUNDAY...
WHILE THE FRONTAL ZONE WEST OF THE MOUNTAINS HAS TEMPORARILY LIFTED
NORTH INTO THE OH VALLEY AS A WARM FRONT THIS EVENING...A WEDGE-LIKE
AIRMASS IS LINGERING OVER VA...WITH THE SURFACE FRONT NEAR THE NC/VA
BORDER. NORTH OF THE FRONT...DENSE FOG HAS ALREADY SET IN. WARM
ADVECTION ATOP THE NOCTURNAL STABLE LAYER SHOULD STRENGTHEN THE
INVERSION...BUT THERE IS VERY LITTLE PRECIP HELPING TO FURTHER LOCK
IN THE AIRMASS. THE RAP SHOWS A SOUTHERN WIND PUSHING INTO VA
OVERNIGHT...BUT THIS MAY BE A LITTLE AGGRESSIVE. THUS..WITH THE
BOUNDARY SO CLOSE TOP THE CWA...HAVE ADDED PATCHY FOG OVERNIGHT FOR
THE FAR NORTHERN AREAS OF FORSYTH...GUILFORD AND PERSON COUNTIES.
SOUTH OF THE BOUNDARY...FAIRLY UNIFORM SOUTH-SOUTHWESTERLY LOW LEVEL
FLOW CONTINUES IN THE WARM SECTOR. THE 00Z KGSO AND KMHX RAOBS SHOW
ALL OF THE MOISTURE CONFINED BELOW 750MB WITH A WEAK CAP JUST
ABOVE. THE FEW SHOWERS THAT HAVE DEVELOPED THIS EVENING HAVE
STRUGGLED TO EXTEND ABOVE 11K FT AND HAVE NOT PRODUCED ANY LIGHTNING
DESPITE SOME WEAK CAPE JUST ABOVE THE CAP. FORCING ALOFT IS
DIFFICULT TO LOCATE IN THE MOIST SOUTHWESTERLY FLOW AHEAD OF THE
MAIN UPPER TROUGH...BUT REGIONAL SURFACE AND 850MB OBS SHOW A WEAK
WAVE NEAR SC/GA COASTAL AREAS. WHILE THIS WAVE IS FORECAST TO
WEAKEN FURTHER AS IT MOVES ALONG THE COAST...MOST OF THE FORECAST
MODELS SHOW A SLUG OF ISENTROPIC LIFT IN THE 295-305K LAYER MOVING
NORTH THROUGH THE COASTAL PLAIN AROUND 09Z. THE AVAILABLE CAMS SHOW
WHAT SHOULD BE SOME LOW TOPPED SHOWERS BRUSHING THE I-95
CORRIDOR...ESPECIALLY OVER THE NORTHERN COASTAL PLAIN. WILL HAVE A
30 POP IN THIS AREA AFTER 09Z...AND KEEP THE MENTION OF ISOLATED
SHOWERS ELSEWHERE.
TEMPS CURRENTLY IN THE UPPER 50S AND LOWER 60S WILL SHOULDN FALL
TOO MUCH MORE UNDER MOSTLY OVERCAST SKIES...SO WILL ONLY ADJUST LOWS
TO MATCH THE CURRENT TRENDS. LOWS 55-61. -BLS
MONDAY:
THERE IS GOOD AGREEMENT WITH THE TIMING OF THE COLD FRONT INTO
WESTERN NC LATE MONDAY AFTERNOON. THE LATE ARRIVAL OF THE SFC COLD
FRONT WILL KEEP THE ASSOCIATED MAIN BAND OF CONVECTION WEST OF THE
AREA UNTIL 21 TO 00Z. PRIOR TO THE ARRIVAL OF THIS BAND...ISOLATED
TO SCATTERED SHOWERS WILL BE POSSIBLE ACROSS CENTRAL NC WITHIN THE
40-50KT H8 LOW-LEVEL JET AND INCREASING RIGHT-ENTRANCE REGION
DYNAMICS. MODELS INDICATE ONLY MARGINAL INSTABILITY(200 TO 500
J/KG)...A LIKELY PRODUCT OF WIDESPREAD CLOUD COVER. GIVEN THE LACK
OF INSTABILITY AND THE SHORTWAVE DYNAMICS RACING OFF TO THE
NORTHEAST(GREAT LAKES)...EXPECT THUNDER TO BE AN EXCEPTION NOT THE
RULE. WILL PUT IN ISOLATED THUNDER IN THE FAR WESTERN ZONES ONLY.
TEMPERATURES WILL BE DEPENDENT ON CLOUD COVER AND PRECIP
COVERAGE...WITH HIGHS A TOUCH COOLER THAN PREVIOUSLY THOUGHT.
HIGHS IN THE UPPER 60S NW TO MID 70S SOUTHEAST WITH BREEZY SWLY
WINDS OF 15 T0 25 MPH.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM SUNDAY...
A COLD FRONT WILL APPROACH AND CROSS THE REGION OVERNIGHT MONDAY
INTO TUESDAY. PRECIP CHANCES WILL RAMP UP NEAR SUNSET ON MONDAY
ACROSS THE WEST AND THEN MOVE EASTWARD THROUGH THE OVERNIGHT HOURS
AND INTO EARLY TUESDAY. IT SHOULD BE NOTED THAT MODELS CONTINUE TO
TREND DRIER FOR CENTRAL NC WITH THE PASSAGE OF THIS COLD FRONT. IN
FACT...MODELS INDICATE A LINE OF SHOWERS ALONG AND AHEAD OF THE
FRONT MOVING INTO THE WESTERN PIEDMONT BY SUNSET...THEN WEAKENING
SIGNIFICANTLY AS IT MOVES EASTWARD INTO THE MORE STABLE AIR OVER THE
PIEDMONT/COASTAL PLAIN. AS A RESULT...WILL MAINTAIN LIKELY POPS FOR
LATE MONDAY/MONDAY EVENING IN THE WEST...WITH ONLY CHANCE POPS
FURTHER EAST TROUGH EARLY TUESDAY. PRECIP SHOULD COME TO AN END
TUESDAY AFTERNOON AS THE FRONT MOVES EAST OF THE AREA. INSTABILITY
APPEARS TO BE MARGINAL (AT BEST) AS THE FRONT CROSSES THE AREA
MONDAY NIGHT...BUT CANNOT COMPLETELY RULE OUT AN ISOLATED
THUNDERSTORM OR TWO.
TEMPS MONDAY NIGHT AND TUESDAY WILL ULTIMATELY BE DETERMINED BY THE
TIMING OF THE FRONT AND ASSOCIATED PRECIP AND EVENTUAL CAA. WITH THE
CURRENT TIMING OF THE FRONT IN MIND...WILL SHOW MILD TEMPS MONDAY
NIGHT...GENERALLY IN THE 50S. HIGHS ON TUESDAY ARE EXPECTED TO BE IN
THE MID/UPPER 50S ACROSS THE NORTHWEST (DUE TO THE EARLIER FRONTAL
PASSAGE) TO THE LOW/MID 60S FURTHER SOUTH AND EAST. THESE HIGHS MAY
VERY WELL OCCUR IN THE MORNING AND THEN FALL THROUGHOUT THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...
TUESDAY NIGHT THROUGH WEDNESDAY...THERE STILL IS QUITE A BIT OF
UNCERTAINTY WITH RESPECT TO THE WEATHER FOR THIS TIME FRAME. ALL THE
MODELS SHOW THE FRONT HANGING NEAR THE COAST WITH MULTIPLE LOW
PRESSURE WAVES TRACKING ALONG IT AND SPREADING PRECIP INTO EASTERN
NC...ALTHOUGH HOW FAR EAST IS IN QUESTION. ALL MODELS ALSO SHOW A
MID LEVEL WAVE TRACKING EASTWARD ACROSS THE AREA DURING THIS TIME
FRAME...ALTHOUGH TIMING/STRENGTH IS NOT WELL AGREED UPON. NOW THE
GFS IS STRONGER AND SLOWER (OPPOSITE OF 24 HOURS AGO) AND ACTUALLY
SPREADS PRECIP ACROSS THE ENTIRE FORECAST AREA LATE TUESDAY NIGHT
INTO WEDNESDAY. THE NAM SUPPORTS THIS SOLUTION SOMEWHAT...BUT THE
ECMWF AND CANADIAN KEEP MOST OF THE PRECIP ACROSS THE EASTERN
PORTIONS OF THE FORECAST AREA. FOR NOW...WILL MAINTAIN FORECAST
CONTINUITY AND SHOW A CHANCE OF RAIN IN THE EAST LATE TUESDAY NIGHT
AND WEDNESDAY...WITH ONLY A SLIGHT CHANCE FURTHER WEST. TEMPS WILL
LIKELY BE NEAR TO SLIGHTLY ABOVE NORMAL DURING THIS TIME FRAME.
THURSDAY THOUGH SUNDAY...CONDITIONS THEN LOOK TO IMPROVE FOR THE END
OF THE WORK WEEK AS SURFACE HIGH PRESSURE AND MID LEVEL RIDGING
BUILD INTO THE AREA. MODELS THEN SHOW THE NEXT SYSTEM APPROACHING
THE REGION OVER THE WEEKEND...WITH CLOUDS AND PRECIP CHANCES
POSSIBLY BEGINNING TO INCREASE LATE SATURDAY (ALTHOUGH TIMING THIS
FAR OUT IS ALWAYS IN QUESTION). TEMPS WILL SLOWLY MODERATE AT THE
END OF THE WEEK AND ESPECIALLY INTO THE WEEKEND AS THE SURFACE HIGH
MOVES OFFSHORE AND SOUTHERLY FLOW RETURNS TO THE AREA.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 145 AM MONDAY...
24-HR TAF PERIOD:
CONFIDENCE IS HIGHER THAN PREVIOUS NIGHTS THAT IFR/LIFR CEILINGS
WILL DEVELOP BETWEEN 06-12Z IN ASSOCIATION WITH AN INCREASINGLY
MOIST LOW-LEVEL SOUTHERLY FLOW...THOUGH SOME UNCERTAINTY PERSISTS...
MORE-SO AT THE EASTERN TERMINALS WHERE IT IS POSSIBLE THAT CEILINGS
AND VISBYS BOUNCE AROUND MORE...OR DO NOT FALL BELOW THE MVFR
CATEGORY. REGARDLESS...EXPECT CEILINGS AND VISBYS TO IMPROVE TO MVFR
BETWEEN 12-15Z AS SOUTHERLY FLOW/MIXING STRENGTHEN IN ADVANCE OF A
COLD FRONT APPROACHING THE MOUNTAINS FROM THE WEST...WITH MVFR OR
VFR CEILINGS DURING THE AFTERNOON. EXPECT SOUTHWESTERLY WINDS TO
BECOME SUSTAINED AT 10-15 KT WITH GUSTS TO 20 KT BY 15Z... FURTHER
INCREASING TO 15-20 KT WITH GUSTS UP TO 30 KT POSSIBLE DURING THE
AFTERNOON. SOUTHWESTERLY WINDS WILL WEAKEN AFTER SUNSET AS THE FRONT
PUSHES INTO THE FOOTHILLS...VEERING TO THE NW/NNW AT 10-15 KT AT
FROPA...WHICH IS ANTICIPATED ~06Z TUE AT INT/GSO...~09Z AT RDU...AND
09-12Z AT FAY/RWI. AT THIS TIME...DO NOT EXPECT MUCH IN THE WAY OF
PRECIPITATION WITH THE FRONT...THOUGH SHOWER ACTIVITY AND LOCALLY
REDUCED CEILINGS WILL BE POSSIBLE BETWEEN 00-12Z TUE AT ALL TAF
SITES.
LOOKING AHEAD:
A PERIOD OF VFR CONDITIONS IS EXPECTED IN THE WAKE OF THE FRONTAL
PASSAGE DURING THE DAY TUE...THOUGH MVFR CEILINGS MAY PERSIST AT THE
FAY/RWI TERMINALS. THE FRONT WILL STALL JUST OFFSHORE THE CAROLINA
COAST TUE NIGHT. EXPECT INCREASING CHANCES FOR RAIN AND CEILINGS
DETERIORATING TO IFR/LIFR AT THE RDU/FAY/RWI TERMINALS AND AT LEAST
MVFR/IFR AT THE INT/GSO TERMINALS BETWEEN 00-12Z WED AS A WAVE OF
LOW PRESSURE DEVELOPS ALONG THE STALLED FRONT. SUB-VFR CEILINGS ARE
EXPECTED TO PERSIST THROUGH THE DAY WED...WITH A RETURN TO DRY/VFR
CONDITIONS WED NIGHT THROUGH THE REMAINDER OF THE WEEK. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...CBL/BLS
SHORT TERM...KRR
LONG TERM....KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
357 AM EST MON DEC 10 2012
.SYNOPSIS...
SOME SHOWERS WILL LINGER ACROSS PARTS OF THE AREA INTO THIS
AFTERNOON AS A COLD FRONT CONTINUES TO PUSH OFF TO THE EAST.
COLDER AIR FILTERING INTO THE AREA BEHIND THE FRONT WILL LEAD TO
FALLING TEMPERATURES THROUGH THIS AFTERNOON. HIGH PRESSURE WILL
BUILD INTO THE REGION THROUGH MID WEEK...LEADING TO DRIER BUT
COOLER CONDITIONS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT EVIDENT ON RADAR PUSHING SLOWLY EAST...CURRENTLY
SITUATED RIGHT ALONG INTERSTATE 71. WIDESPREAD SHOWERS ARE
CONTINUING OUT AHEAD OF THE FRONT ACROSS SOUTHEASTERN PORTIONS OF
OUR FA. THE FRONT WILL CONTINUE TO PUSH EAST THROUGH THIS
AFTERNOON...BUT THE NAM AND RAP ARE BOTH INDICATING SOME
ADDITIONAL PCPN OVERRUNNING THE FRONT BACK UP ACROSS PORTIONS OF
OUR FA THROUGH THIS AFTERNOON. THE GFS AND ECMWF ARE NOT QUITE AS
AGGRESSIVE WITH THIS BUT THEY TOO ARE AT LEAST HINTING AT THE
POSSIBILITY OF IT. AS A RESULT...WILL ALLOW FOR PCPN TO LINGER
BACK FARTHER TO THE WEST THEN CURRENTLY INDICATED BY THE RADAR
TRENDS. DUE TO THE MODEL DIFFERENCES...THE WESTERN EXTENT OF THIS
IS IN DOUBT THOUGH AND HAVE GENERALLY TRENDED CLOSE TO THE 03Z
SREF WHICH KEEPS LIKELY OR HIGHER POPS PRETTY CLOSE TO ONGOING
PCPN. WILL THEN TAPER BACK TO CHANCE POPS HEADING BACK THE
NORTHWEST TO ACCOUNT FOR THE UNCERTAINTY. DEVELOPING CAA BEHIND
THE FRONT WILL LIKELY ALLOW FOR SOME FALLING TEMPERATURES THROUGH
THIS AFTERNOON. IF PCPN EXTENDS FAR ENOUGH BACK TO THE WEST...WE
COULD END UP WITH A RAIN SNOW MIX ALONG THE WESTERN FRINGE OF THE
PCPN BY LATER THIS AFTERNOON AS THE LOW LEVELS BEGIN TO COOL. THE
NAM AND GFS ARE BOTH TRYING TO INDICATE SOME LIGHT ACCUMULATIONS
BY EVENING ACROSS PARTS OF OUR WEST. HOWEVER...THINK THIS IS
PROBABLY OVERDONE AS THE GROUND TEMPERATURE IS STILL WARM. IN
ADDITION...THE COBB METHOD IS INDICATING MORE OF A RAIN SNOW MIX
WITH NO ACCUMULATION AS SURFACE TEMPERATURES SHOULD AT LEAST
REMAIN ABOVE FREEZING THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
CYCLONIC LOW LEVEL FLOW AND CAA WILL CONTINUE INTO THIS EVENING
WITH BOTH THE NAM AND GFS INDICATING A WEAK SURFACE TROUGH
PIVOTING DOWN FROM THE NORTH. THIS MAY BE ENOUGH TO PRODUCE A FEW
LIGHT SNOW SHOWERS OR FLURRIES INTO TONIGHT. LOW LEVEL FLOW WILL
BEGIN TO BACK LATER TONIGHT AS HIGH PRESSURE STARTS TO BUILD
IN FROM THE WEST. THIS SHOULD ALLOW FOR ANY PCPN TO TAPER OFF BY
LATE TONIGHT. HIGH PRESSURE WILL THEN BUILD INTO THE REGION
TUESDAY THROUGH WEDNESDAY...LEADING TO DRY CONDITIONS AND MORE
SEASONABLE TEMPERATURES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SPRAWLING HIGH PRESSURE WILL BE RUNNING FROM NEW ENGLAND BACK INTO
THE OHIO VALLEY AT THE BEGINNING OF THE PERIOD. THE HIGH WILL
CONTROL THE REGIONS WEATHER INTO FRIDAY.
MODELS HAVE DIVERGED SOME WITH THEIR SOLUTION FOR THE SYSTEM THAT
KICKS OUT OF THE PLAINS FRIDAY INTO SATURDAY. THE GFS IS MUCH WEAKER
AND QUICKER WITH THE SYSTEM AND THEREFORE PUSHES A CDFNT ACROSS THE
FA SATURDAY...WITH COOLER AND DRIER AIR WORKING IN FOR SUNDAY. THE
ECMWF...DGEX AND TO SOME EXTENT THE CMC ARE SLOWER AND DEEPER. THIS
DELAYS THE START OF THE PCPN BY ABOUT 6 HOURS...BUT ALSO DELAYS
FROPA UNTIL SUNDAY. THE GFS LOOKS LIKE THE OUTLIER...SO LEANED
TOWARDS THE CONSENSUS SOLUTION. SO KEPT HIGHER POPS SATURDAY NIGHT
INTO SUNDAY AND WENT WARMER OVERNIGHT LOWS SATURDAY NIGHT.
WITH HIGH OVER THE REGION INTO FRIDAY...THERE SHOULD BE PLENTY OF
SUNSHINE. COULD SEE SOME PERIODS OF AC OR CI AS WEAK S/W WORKS
THROUGH THE H5 FLOW.
A GRADUAL WARMING WILL OCCUR DURING THE LATER HALF OF THE WEEK. ON
WEDNESDAY...HIGHS ARE EXPECTED TO PUSH INTO THE LOWER TO MID 40S.
HIGHS WILL PUSH INTO THE UPPER 40S TO LOWER 50S BY THE END OF THE
WEEK AND OVER THE WEEKEND.
ANOTHER COOL NIGHT IS EXPECTED WEDNESDAY NIGHT WITH TEMPERATURES
FALLING BACK INTO THE 20S BEFORE THE WARMER AIR BEGINS TO WORK IN
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
A SWATH OF LIGHT RAIN WILL SLOWLY SLIDE EASTWARD THROUGH THE
EARLY MORNING HOURS. THE MAIN AFFECTS FROM THIS WILL BE OCCASIONAL
MVFR VSBYS ALONG AND SOUTH OF THE I-71 CORRIDOR WITH THE BACK EDGE
ALREADY REACHING KCVG/KILN. A COLD FRONT ABOUT TO PASS KDAY WILL
BRING A WIND SHIFT OUT OF THE NORTHEAST AND A BAND OF IFR CIGS TO
THE AREA. THESE CIGS SHOULD SHIFT EAST AND REACH THE REST OF THE
TERMINALS OVER THE NEXT FEW HOURS. BEHIND THIS BAND OF IFR
CIGS...SOME DRIER AIR SHOULD BREAK THE LOW CLOUD DECK. THIS WILL
ALLOW FOR AN OPPORTUNITY FOR VFR CIGS AT THE WESTERN TERMINALS
KDAY/KCVG/KLUK BEFORE SUNRISE...LASTING INTO THE AFTERNOON. TO THE
EAST...VFR CIGS SHOULD RETURN A LITTLE LATER IN THE MORNING.
ADDITIONAL LIGHT RAIN OVERRUNNING THE ADVANCING FRONT MAY AFFECT
TERMINALS ALONG AND SOUTH OF I-71 THROUGHOUT THE MORNING. BY THE
MID AFTERNOON ALL TERMINALS ARE EXPECTED TO BE DRY. WRAPAROUND
MOISTURE FROM DEPARTING LOW PRESSURE WILL THEN BRING MVFR AND IFR
CIGS TO THE AREA DURING THE EVENING. IN ADDITION...SNOW SHOWERS
WILL ALSO BE POSSIBLE DURING THIS TIME...MAINLY ACROSS THE
NORTHERN TERMINALS.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE MONDAY NIGHT
INTO TUESDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 AM EST MON DEC 10 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST OVERNIGHT WHICH WILL DRAG A COLD
FRONT ACROSS THE REGION LATE TONIGHT AND EARLY MONDAY MORNING.
HIGH PRESSURE BUILDING INTO THE CENTRAL PART OF THE COUNTRY WILL
HELP USHER IN DRIER AND COLDER AIR BEHIND THIS FRONT.
&&
.NEAR TERM /THROUGH TODAY/...
SHOWERS HAVE BEEN FILLING IN AS THEY MOVE INTO THE FORECAST AREA
THIS EVENING AHEAD OF AN APPROACHING LOW AND COLD FRONT. ISOLATED
TO SCATTERED EMBEDDED THUNDERSTORMS HAVE ALSO BEEN OCCURRING WITH
THE BETTER COVERAGE IN THE SOUTHWEST COUNTIES. WILL CONTINUE TO
SEE SHOWERS AND THUNDERSTORMS PUSH ACROSS THE REGION OVERNIGHT.
EXPECT MUCH OF THIS ACTIVITY TO DIMINISH CONSIDERABLY AS THE COLD
FRONT MOVES INTO THE AREA LATER TONIGHT.
COLD FRONT WILL BISECT THE REGION AT DAYBREAK AND CONTINUE THROUGH
THE REST OF THE FORECAST AREA EARLY IN THE MORNING. TEMPERATURES
WILL REMAIN QUITE MILD UNTIL FRONTAL PASSAGE WITH READINGS FALLING
THEREAFTER. APPEARS THAT MANY LOCATIONS WILL HAVE A 12Z HIGH AND A
13Z LOW.
12Z HIGH RESOLUTION NAM-ARW HAD SHOWN A SECONDARY WAVE OF
PRECIPITATION BEHIND THE COLD FRONT SPREADING NORTHEAST IN THE
MORNING. PAST FEW RUNS OF THE RAP HAVE LEANED TOWARDS THIS AND 00Z
NAM SHOWS IT TO SOME EXTENT. SO HAVE INCREASED POPS AGAIN DURING
THE MORNING MAINLY SOUTH AND EAST OF I-71. THIS WILL ALL PUSH OFF
TO THE EAST DURING THE AFTERNOON. PRECIPITATION SHOULD ALL BE RAIN
AS COOL DOWN WILL BE GRADUAL AFTER INITIAL SURGE WITH THE FRONT.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
A FEW LINGERING CLOUDS AND THE COLD PUSH DOWNWIND OF LAKE
MICHIGAN COULD SPARK SOME FLURRIES OR A LIGHT SNOW SHOWER EARLY
MONDAY EVENING WITH LITTLE IF ANY NEGATIVE IMPACTS TO THE REGION.
SKIES WILL REMAIN GENERALLY CLOUDY UNTIL LATE TUESDAY WHEN
RELATIVELY WARMER AIR ALOFT IS FOUND ON THE BACK SIDE OF THE
DEPARTING RIDGE OF H8 HIGH PRESSURE. A SURFACE RIDGE OF HIGH
PRESSURE WILL ALSO BECOME MORE ESTABLISHED OVER THE AREA AT THIS
TIME. TEMPERATURES THROUGH THIS TIME WILL BE COLDER BUT VERY NEAR
CLIMATOLOGICAL NORMALS FOR THIS TIME OF YEAR.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
SPRAWLING HIGH PRESSURE WILL BE RUNNING FROM NEW ENGLAND BACK INTO
THE OHIO VALLEY AT THE BEGINNING OF THE PERIOD. THE HIGH WILL
CONTROL THE REGIONS WEATHER INTO FRIDAY.
MODELS HAVE DIVERGED SOME WITH THEIR SOLUTION FOR THE SYSTEM THAT
KICKS OUT OF THE PLAINS FRIDAY INTO SATURDAY. THE GFS IS MUCH WEAKER
AND QUICKER WITH THE SYSTEM AND THEREFORE PUSHES A CDFNT ACROSS THE
FA SATURDAY...WITH COOLER AND DRIER AIR WORKING IN FOR SUNDAY. THE
ECMWF...DGEX AND TO SOME EXTENT THE CMC ARE SLOWER AND DEEPER. THIS
DELAYS THE START OF THE PCPN BY ABOUT 6 HOURS...BUT ALSO DELAYS
FROPA UNTIL SUNDAY. THE GFS LOOKS LIKE THE OUTLIER...SO LEANED
TOWARDS THE CONSENSUS SOLUTION. SO KEPT HIGHER POPS SATURDAY NIGHT
INTO SUNDAY AND WENT WARMER OVERNIGHT LOWS SATURDAY NIGHT.
WITH HIGH OVER THE REGION ON WEDNESDAY INTO FRIDAY...THERE SHOULD BE
PLENTY OF SUNSHINE. COULD SEE SOME PERIODS OF AC OR CI AS WEAK S/W
WORKS THROUGH THE H5 FLOW.
A GRADUAL WARMING WILL OCCUR DURING THE LATER HALF OF THE WEEK. ON
WEDNESDAY...HIGHS ARE EXPECTED TO PUSH INTO THE LOWER TO MID 40S.
HIGHS WILL PUSH INTO THE UPPER 40S TO LOWER 50S BY THE END OF THE
WEEK AND OVER THE WEEKEND.
ANOTHER COOL NIGHT IS EXPECTED WEDNESDAY NIGHT WITH TEMPERATURES
FALLING BACK INTO THE 20S BEFORE THE WARMER AIR BEGINS TO WORK IN
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A SWATH OF LIGHT RAIN WILL SLOWLY SLIDE EASTWARD THROUGH THE
EARLY MORNING HOURS. THE MAIN AFFECTS FROM THIS WILL BE OCCASIONAL
MVFR VSBYS ALONG AND SOUTH OF THE I-71 CORRIDOR WITH THE BACK EDGE
ALREADY REACHING KCVG/KILN. A COLD FRONT ABOUT TO PASS KDAY WILL
BRING A WIND SHIFT OUT OF THE NORTHEAST AND A BAND OF IFR CIGS TO
THE AREA. THESE CIGS SHOULD SHIFT EAST AND REACH THE REST OF THE
TERMINALS OVER THE NEXT FEW HOURS. BEHIND THIS BAND OF IFR
CIGS...SOME DRIER AIR SHOULD BREAK THE LOW CLOUD DECK. THIS WILL
ALLOW FOR AN OPPORTUNITY FOR VFR CIGS AT THE WESTERN TERMINALS
KDAY/KCVG/KLUK BEFORE SUNRISE...LASTING INTO THE AFTERNOON. TO THE
EAST...VFR CIGS SHOULD RETURN A LITTLE LATER IN THE MORNING.
ADDITIONAL LIGHT RAIN OVERRUNNING THE ADVANCING FRONT MAY AFFECT
TERMINALS ALONG AND SOUTH OF I-71 THROUGHOUT THE MORNING. BY THE
MID AFTERNOON ALL TERMINALS ARE EXPECTED TO BE DRY. WRAPAROUND
MOISTURE FROM DEPARTING LOW PRESSURE WILL THEN BRING MVFR AND IFR
CIGS TO THE AREA DURING THE EVENING. IN ADDITION...SNOW SHOWERS
WILL ALSO BE POSSIBLE DURING THIS TIME...MAINLY ACROSS THE
NORTHERN TERMINALS.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE MONDAY NIGHT
INTO TUESDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS TULSA OK
334 AM CST MON DEC 10 2012
.DISCUSSION...
NARROW BAND OF SNOW CONTINUES TO PROGRESS QUICKLY EASTWARD ACROSS
SOUTHERN OK / NW TX AHEAD OF THE UPPER TROUGH AXIS. SHORT TERM
DATA HAVE ALIGNED STRONG LIFT WITHIN A SATURATED DENDRITIC GROWTH ZONE
NEAR THE RED RIVER...AND RECENT OBS AND REPORTS NEAR KSPS SUPPORT
THIS BRIEF BUT INTENSE SNOWFALL AREA. LATEST RUC DATA SHIFT THE
FRONTOGENETIC FORCING MOST ALIGNED WITHIN THIS ZONE NORTHEASTWARD
WHILE WEAKENING IT OVER THE NEXT 4-6 HOURS. THUS FORECAST WILL
INCLUDE A HIGHER MEASURABLE SNOW POTENTIAL FOR PORTIONS OF FAR SE
OK BUT ANY ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT. ANY PRECIP
WILL QUICKLY SHIFT EAST OF THE FORECAST AREA BY LATE MORNING.
TEMPS WILL STRUGGLE TO WARM TODAY HOWEVER THE SUN WILL MAKE AN
APPEARANCE WHICH HAS BEEN A RARE SIGHT RECENTLY. VERY COLD TEMPS
TONIGHT WITH LOW DEWPOINTS AND LIGHT WINDS. WHILE NOT CURRENTLY
FORECAST...A FEW LOWS AROUND 10 DEGREES ARE CERTAINLY POSSIBLE.
TEMPS MODERATE BEGINNING TUESDAY AND RETURN ABOVE NORMAL BY
THURSDAY. THE NEXT WAVE TRACKING ACROSS THE SOUTHERN TIER STATES
ARRIVES FRIDAY INTO SATURDAY. WHILE THE TIMING IS IN GENERAL
AGREEMENT AMONGST DATA...THERE ARE TWO MAIN CAMPS REGARDING THE
STRENGTH OF THE WAVE. THE UKMET/ECMWF ARE STRONGER OFFERING A
STOUT CLOSED MID LEVEL LOW...WHILE THE GFS/CANADIAN ARE MORE OPEN
WITH THE WAVE. THE FORECAST WILL MAINTAIN POPS IN THE CHANCE
CATEGORY GIVEN RECENT STRUGGLES TO PRODUCE WIDESPREAD MEANINGFUL
PRECIP...HOWEVER SHOULD THE STRONGER SOLUTION BECOME MORE APPARENT
THEN CHANCES WILL OBVIOUSLY INCREASE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 36 20 47 25 / 10 0 0 0
FSM 40 20 47 23 / 10 0 0 0
MLC 38 16 47 20 / 20 0 0 0
BVO 37 13 48 19 / 10 0 0 0
FYV 35 14 42 17 / 10 0 0 0
BYV 36 18 44 22 / 10 0 0 0
MKO 37 16 46 20 / 10 0 0 0
MIO 35 16 46 22 / 10 0 0 0
F10 37 18 46 22 / 10 0 0 0
HHW 42 19 48 22 / 40 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....07
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
932 AM EST MON DEC 10 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EST MON DEC 10 2012
A WEAK WAVE MOVING THROUGH THE AREA TODAY COULD PROMPT A
FEW SNOWFLAKES ACROSS THE NORTHERN COUNTIES. TONIGHT HIGH PRESSURE
WILL BUILD INTO THE AREA AND BRING DRY WEATHER WHICH WILL LAST
THROUGH FRIDAY. BY FRIDAY NIGHT ANOTHER SYSTEM WILL APPROACH THE
AREA AND BRING CHANCES FOR RAIN THAT WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 355 AM EST MON DEC 10 2012
AT 8Z RADAR MOSAIC SHOWED ALL RAIN HAD MOVED SOUTHEAST OF THE AREA.
SURFACE ANALYSIS SHOWED SURFACE LOW CENTERED OVER LAKE ERIE WITH A
COLD FRONT STRETCHING SOUTHWEST THROUGH WESTERN OHIO AND CENTRAL
KENTUCKY AND TENNESSEE TO NORTHERN MISSISSIPPI. MODELS SHOW THE LOW
CONTINUING TO MOVE NORTHEAST THROUGH THE DAY WITH THE FRONT BEING
DRAGGED EAST AS WELL. DRY AIR WAS WORKING ITS WAY INTO CENTRAL
INDIANA. A COUPLE MODELS ARE SHOWING SOME OF THE RAIN MAKING ITS WAY
BACK NORTH INTO THE SOUTHERN COUNTIES BUT MAJORITY ARE
NOT...INCLUDING THE RAP WHICH SEEMS TO HAVE A GOOD HANDLE ON CURRENT
PRECIP AREA...SO IT LOOKS UNLIKELY THAT IT WOULD GET THIS FAR NORTH.
WILL JUST INCLUDE A SLIGHT CHANCE FOR RAIN IN THE FAR SOUTHEAST
THROUGH THE MORNING.
MODELS SHOW A WEAK UPPER WAVE MOVING THROUGH THE NORTH IN
THE AFTERNOON/EVENING. NOT A LOT OF MOISTURE TO WORK WITH BUT COULD
PROMPT SOME FLURRIES ACROSS THE NORTHERN HALF OR SO OF THE AREA.
WITH 850 MB WINDS OUT OF THE NORTH TO NORTHEAST BRIEFLY COULD
PROVIDE SOME LAKE ENHANCEMENT TO THESE FLURRIES AND SO INCLUDED A
SLIGHT CHANCE OF MEASURABLE SNOW IN THE FAR NORTH TO COVER THIS
POSSIBILITY. STILL LITTLE TO NO ACCUMULATION EXPECTED.
ALTHOUGH DRY AIR ADVECTS IN ALOFT TIME HEIGHTS SHOW LOW LEVELS
REMAINING SATURATED. COMBINING THAT WITH CURRENT SATELLITE TRENDS
AND LOW CLOUDS EXTENDING BACK INTO WESTERN IOWA AND MINNESOTA THINK
SKIES WILL REMAIN CLOUDY THROUGH TODAY AND TONIGHT. FOR TEMPERATURES
WENT A LITTLE COLDER THAN CONSENSUS WITH COLD ADVECTION AND CLOUDY
SKIES.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 355 AM EST MON DEC 10 2012
FORECAST FOCUS IS ON TEMPERATURES. MODELS IN GOOD AGREEMENT SO WILL
USE A CONSENSUS. TONIGHT AN UPPER WAVE WILL BE MAKING IT/S EXIT OF
THE AREA. WITH LAKE ENHANCEMENT STILL BRIEFLY AVAILABLE INCLUDED
SOME FLURRIES IN THE NORTHEAST AS IT LEAVES. AFTER THAT HIGH
PRESSURE BUILDS IN FOR THE REMAINDER OF THE SHORT TERM BRINGING WITH
IT CLEARING SKIES FROM ON TUESDAY AND THEN MOSTLY CLEAR THROUGH THE
SHORT TERM AND SLOWLY WARMING TEMPERATURES AFTER TUESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 305 AM EST MON DEC 10 2012
MAIN FOCUS TO THE EXTENDED WILL BE ON TIMING AND COVERAGE OF POPS
ACROSS CENTRAL INDIANA ASSOCIATED WITH A STRONG WEEKEND SYSTEM.
MODELS HAVE LARGE DIFFERENCES ON TIMING AND STRENGTH OF THE
AFOREMENTIONED STRONG UPPER AND SURFACE SYSTEMS...HOWEVER THE 00Z
ECMWF AND CANADIAN ARE THE CLOSEST WITH THE LATTER JUST A TOUCH
FASTER. BOTH WERE SHOWING NEGATIVELY TILTED UPPER TROUGHS AND SUB
1000 MILLIBAR SURFACE LOWS MOVING TO NEAR SOUTHERN LAKE MICHIGAN
LATE SATURDAY. REGARDLESS...ALL MODELS ARE SUGGESTING CHANCE POPS
ESPECIALLY WEST FRIDAY NIGHT WITH WIDESPREAD ACTIVITY ON SATURDAY
AND THEN LESSENING CHANCES SATURDAY NIGHT AND SUNDAY AS THE SYSTEM
LIFTS NORTHEAST INTO SOUTHEASTERN CANADA. REGIONAL INITIALIZATION
REFLECTS THIS WITH LIKELY POPS ON SATURDAY AND LESSER CHANCES FRIDAY
NIGHT AND SATURDAY NIGHT INTO SUNDAY. SO...WILL NOT MAKE ANY
CHANGES.
THE EXTENDED WILL START OFF WITH SURFACE HIGH PRESSURE ACROSS THE
SOUTHEASTERN STATES AND INCREASING SOUTHWEST FLOW ACROSS THE OHIO
VALLEY AHEAD OF THE AFOREMENTIONED WEATHER MAKER. THIS WILL ALLOW
FOR ABOVE NORMAL TEMPERATURES CLIMAXING ON SATURDAY IN THE UPPER 40S
NORTH AND LOWER 50S SOUTH. BEHIND THE FRONT...TEMPERATURES WILL BE
NEAR NORMAL. WILL ACCEPT REGIONAL INITIALIZATION TEMPERATURES
ESPECIALLY WITH THE MODEL DIFFERENCES IN PLAY.
&&
.AVIATION /DISCUSSION FOR THE 10/15Z TAF UPDATE/...
ISSUED AT 932 AM EST MON DEC 10 2012
ADDED TEMPO GROUPS TO IND/BMG FOR BRIEF DROPS INTO HIGH END IFR
TERRITORY ON CEILINGS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 440 AM EST MON DEC 10 2012
MVFR CEILINGS EXPECTED THROUGH MUCH OF THE TAF PERIOD IMPROVING TO
VFR AFTER 07Z TUESDAY. COULD ALSO SEE A FEW AFTERNOON FLURRIES AS A
WEAK UPPER WAVE MOVES THROUGH. OTHERWISE...NORTHWEST WINDS AT 10
KNOTS OR SO WILL DROP BELOW 10 KNOTS AFTER 00Z. WINDS AND MUCH DRIER
AIR WILL PREVENT ANY VISIBILITY RESTRICTIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....MK
AVIATION...MK/NIELD
AREA FORECAST DISCUSSION
NWS GOODLAND KS
439 AM MST MON DEC 10 2012
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
04Z WATER VAPOR IMAGERY INDICATED TROUGH AXIS CENTERED OVER THE
CWA WITH BROAD RIDGING ACROSS THE WEST COAST. RAP DYNAMIC TROPOPAUSE
ANALYSIS INDICATED SHORT WAVE TROUGH MOVING OVER MONTANA...BUT DID
NOT APPEAR TO BE MUCH OF A RESPONSE ON WV IMAGERY. AT THE
SFC...RIDGE AXIS WAS LOCATED ALONG A KITR TO KANW LINE WITH
TEMPERATURES ALREADY IN THE SINGLE DIGITS ACROSS THE AREA.
MAIN SHORT TERM CONCERNS WILL BE WIND CHILLS THIS MORNING FOLLOWED
BY HOW QUICKLY TEMPERATURES RECOVER THROUGH THE MIDDLE OF THE WEEK.
EARLY MORNING HOURS...TEMPS HAVE FALLEN TO SEVERAL DEGREES BELOW
ZERO ACROSS NORTHEAST CWA WITH WINDS AROUND 10 MPH CREATING WIND
CHILLS IN THE -15 TO -20 RANGE. ALTHOUGH SOME SLIGHT WARMING HAS
BEEN NOTED ACROSS EASTERN COLORADO IN RESPONSE TO CONTINUED WESTERLY
FLOW/WAA...WILL LIKELY BE SEVERAL HOURS BEFORE THAT HAS A MEANINGFUL
IMPACT ACROSS NORTHEAST CWA. ALTHOUGH WINDS ARE NOT STRONG...THINK
CURRENT TEMPS WARRANT A WIND CHILL ADVISORY FOR THE MORNING HOURS.
WHILE CONDITIONS HAVE ALREADY OCCURRED ACROSS EASTERN
COLORADO...AFOREMENTIONED WARMING TREND IN OBS LEADS ME TO THINK
THREAT NOT GREAT IN THIS AREA.
TODAY...WEAK SHORT WAVE TROUGH WILL APPROACH FROM THE NORTH THIS
MORNING...BUT WITH VERY STABLE CONDITIONS EXPECTED FROM NEAR TERM
MODELS AND 00Z OBSERVATIONS AM DOUBTFUL THAT THIS INITIAL TROUGH WILL
DO MORE THAN CREATE A FEW HIGH CLOUDS THROUGH THE MORNING HOURS.
MAIN ISSUE TODAY WILL BE THE GUSTY WINDS THIS AFTERNOON AND HOW
QUICKLY TDS RECOVER FROM INITIAL VERY LOW VALUES AS POTENTIAL EXISTS
FOR LOW END CRITICAL FIRE WEATHER CONDITIONS TODAY. WINDS WILL PICK
UP INTO THE 15 TO 25 MPH RANGE DURING THE AFTERNOON...BUT THINK TDS
WILL ACTUALLY RISE SEVERAL DEGREES WITH VERTICAL MIXING. CURRENT
THOUGHTS KEEP THE HIGHEST WINDS AND DRIEST HUMIDITIES NOT VERY
COLOCATED AND WITH POTENTIAL FOR RISING AFTERNOON TDS...DO NOT PLAN
ON ISSUING A RFW AT THE MOMENT.
TONIGHT-TOMORROW...1.5 PVU FIELDS INDICATE SEVERAL SMALL SCALE SHORT
WAVE TROUGHS MOVING THROUGH THE FLOW TONIGHT...WITH STRONGEST (AT
LEAST FROM A PV PERSPECTIVE) COMING THROUGH THE CWA ON TUESDAY. GFS
AND NAM DIFFER ON STABILITY PROFILES OVERNIGHT WITH GFS INDICATING A
POCKET OF NEAR NEUTRAL CONDITIONS ACROSS WESTERN CWA BETWEEN 0 AND
06Z. WHILE NAM IS SLIGHTLY MORE STABLE...POINT SOUNDINGS DO INDICATE
SNOW GROWTH ZONE NOT TO FAR ABOVE THE SURFACE WITH A PERIOD OF ASCENT
MAXIMIZED IN THIS AREA. DO NOT THINK LIFT WILL BE ENOUGH FOR
MEANINGFUL PRECIP...BUT A FLURRIE OR TWO DOES NOT LOOK UNREASONABLE.
DESPITE AN APPARENTLY STRONGER TROUGH ON TUESDAY...NEAR GROUND SNOW
GROWTH ZONE DISAPPEARS AND OVERALL PROFILES ARE MUCH MORE
STABLE...SO DO NOT EXPECT FLURRIES TO CARRY ON THROUGH THE DAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
TUESDAY NIGHT-WEDNESDAY NIGHT...QUIET WEATHER EXPECTED FOR THE
PERIOD AS SHORT WAVE RIDGING WILL BUILD OVER THE AREA AS FLOW
BECOMES MORE AMPLIFIED IN RESPONSE TO TROUGH DEVELOPING OVER WEST
COAST. THINK A RAPID WARM UP IS POSSIBLE...WITH TEMPS APPROACHING
UPPER 50S TO LOW 60S BY WEDNESDAY. AM A LITTLE CONCERNED THAT
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ON WEDNESDAY AS
DEWPOINTS WILL REMAIN FAIRLY LOW AND NOT UNHEARD OF FOR DEVELOPING
LEE TROUGH TO BRING GUSTY WINDS. RIGHT NOW...THINGS LOOK TOO
MARGINAL FOR POTENTIAL WATCH...BUT WILL KEEP AN EYE ON AS PERIOD
APPROACHES.
THURSDAY-MONDAY...
SW FLOW WILL BE IN PLACE THURSDAY AS DEEP TROUGH DEVELOPS OVER THE
WESTERN US...WHICH SHOULD KEEP CONDITIONS MILD AND DRY OVER THE CWA.
HIGHS SHOULD BE A LITTLE COOLER FROM THE HIGHS ON WED...HOWEVER MOST
LOCATIONS SHOULD STILL BE IN THE MID 50S.
OPERATIONAL GUIDANCE IS IN DECENT AGREEMENT ON GENERAL TIMING/TRACK
OF TROUGH AS IS MOVES FROM THE SW US AND ACROSS SOUTHERN KANSAS
FRIDAY THROUGH SATURDAY...WITH CLOSED CENTER MOVING ACROSS SOUTHERN
KS. THIS COULD PUT OUR EASTERN CWA NEAR POSSIBLE DEFORMATION
ZONE/HEAVY SNOW BAND FRIDAY NIGHT. GEFS ENSEMBLES STILL SHOWING
GREATER SPREAD WITH GEFS MEAN MUCH SLOWER AND LESS AMPLIFIED AS A
RESULT. THERE HASNT BE A LOT OF RUN TO RUN CONTINUITY THE LAST FEW
DAYS...SO A LOT CAN STILL CHANGE CONSIDERING THE TIME RANGE. BASED
ON CURRENT RUNS IT DOES APPEAR CHANCES FOR A WINTER STORM DEVELOPING
OVER PARTS OF KANSAS COULD BE INCREASING. FOR OUR CWA THE FAVORED
LOCATIONS WOULD BE ACROSS THE EAST WHERE LIGHT SNOW ACCUMULATIONS
ARE POSSIBLE. I DID INCREASE POPS TO 40 ACROSS THE EAST THIS
FORECAST CYCLE...WITH CONFIDENCE TOO LOW TO GO MUCH HIGHER.
THERE IS SIGNIFICANT SPREAD IN THE UPPER LEVEL PATTERN AFTER THIS
SYSTEM SHIFTS EAST. GEFS AND GFS ARE GENERALLY SHOWING A
WESTERLY/ZONAL PATTERN ...WHILE ECMWF IS TRYING TO SHOW A MUCH MORE
PROGRESSIVE/ACTIVE PATTERN. REGARDLESS OF SOLUTION IT DOES APPEAR
THE ACTIVE STORM TRACK IS FAVORING AREAS OUTSIDE OF OUR CWA...SO IM
KEEPING LATER PERIODS DRY FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 437 AM MST MON DEC 10 2012
VFR CONDITIONS EXPECTED OVER THE NEXT 24 HOURS WITH GUSTY WEST
WINDS EXPECTED TODAY WITH PERIODS OF SCATTERED TO BROKEN MID LEVEL
CLOUDS. OVERNIGHT CEILINGS WILL FALL TO AROUND 3500 FEET...BUT
WIDESPREAD AND PERSISTENT FLIGHT RESTRICTIONS ARE NOT EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY UNTIL 8 AM MST /9 AM CST/ THIS MORNING FOR
KSZ001>003-013>015.
CO...NONE.
NE...WIND CHILL ADVISORY UNTIL 8 AM MST /9 AM CST/ THIS MORNING FOR
NEZ079>081.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/DR
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
921 AM EST MON DEC 10 2012
.SYNOPSIS...
A WARM FRONT LIFTS VERY SLOWLY NORTH THROUGH THE MID ATLANTIC THIS
MORNING. A COLD FRONT APPROACHES FROM THE WEST THROUGH THIS
EVENING...BEFORE PUSHING ACROSS THE AREA LATE TONIGHT INTO EARLY
TUESDAY. LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE FRONT
TUESDAY NIGHT AND TRACKS OFF THE COAST WEDNESDAY. HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS SHOWS LOW PRESSURE OVER EASTERN GREAT LAKES
WITH WEAK QUASI-STATIONARY FRONT STILL DRAPED OVER NORTHERN
PIEDMONT. VISIBILITIES HAVE BEGUN TO IMPROVE AS EXPECTED
THROUGHOUT THE REGION.
LATEST SUBJECTIVE UPPER AIR ANALYSIS SHOWS POSITIVELY TILTED UPPER
TROUGH AXIS EXTENDING FROM THE UPPER MID WEST BACK INTO THE
CENTRAL HIGH PLAINS. BROAD, MOIST SW FLOW AHEAD OF THIS FEATURE
FROM THE SOUTHEASTERN CONUS UP INTO THE MID-ATLANTIC REGION. SOME
SHRAS NOTED ON REGIONAL RADAR MOSAIC IN ASSOCIATION WITH WEAK
SHORTWAVE TROUGH PUSHING ACROSS THE CAROLINA COASTAL PLAIN. MODELS
SEEM TO BE HAVING TROUBLE WITH THIS FEATURE, SO HAVE USED A BLEND
OF RUC AND SREF IN QUICKLY SCOOTING THIS WAVE OFFSHORE BY MID TO
LATE MORNING, WITH A FEW SHOWERS PUSHING INTO FAR EASTERN ZONES.
QPF LOOKING RATHER LIGHT...ON THE ORDER OF A FEW HUNDREDTHS TO A
TENTH OF AN INCH.
NORTHERN STREAM TROUGH LIFTS NORTH OF THE GREAT LAKES TODAY, AS
NEXT SOUTHERN PLAINS DAMPENS AS IT LIFTS FROM SOUTHERN PLAINS
TOWARDS THE OHIO VALLEY BY TONIGHT. AS THIS HAPPENS, SFC LOW OVER
THE EASTERN GRT LAKES WILL LIFT INTO QUEBEC WITH ATTENDANT SFC
COLD FRONT SWEEPING EASTWARD BY TONIGHT. AS IS USUALLY THE CASE,
MODELS APPEAR TOO AGGRESSIVE THIS MORNING IN PUSHING STALLED
FRONTAL BOUNDARY NORTH THIS MORNING, AND TRYING TO CLEAR OUT LOW
CLOUDS. WILL CONTINUE WITH PARTLY TO MOSTLY CLOUDY WORDING THROUGH
THE DAY, W/ HIGHS IN THE MID 60S TO LOW 70S, WITH A FEW MID 70S
POSSIBLE GIVEN PRESENT TEMPERATURES ALREADY IN THE L-M 60S ACROSS
SE VA/NE NC.
FORCING FOR ASCENT APPEARS RATHER ANEMIC THROUGH MUCH OF THE DAY
AND DESPITE MILD TEMPS AND LLVL MOISTURE, FORECAST SOUNDINGS
INDICATE DESTABILIZATION WILL BE DIFFICULT GIVEN SIGNIFICANT CLOUD
COVER THROUGH MOST OF THE DAY. THUS, EXPECT MOST OF THE DAY TO BE
DRY OVER THE AREA. DO INCREASE RAIN CHANCES OVER THE FAR NW BY THE
LATE AFTERNOON AS FRONT APPROACHES FROM THE WEST.
AS MENTIONED EARLIER, THE UPPER TROUGH WILL DAMPEN/WEAKEN AS IT
PUSHES ACROSS THE OHIO VALLEY INTO THE NORTHERN MID ATLANTIC
TONIGHT INTO EARLY TUESDAY, DRAGGING THE COLD FRONT ACROSS THE
CWA TONIGHT AND OFF THE COAST EARLY TUESDAY MORNING. HIGH END CHC
TO LIKELY POPS (50-60%) WILL BE MAINTAINED WITH THE FRONTAL
PASSAGE TONIGHT ACROSS THE WEST, ALTHOUGH QPF WILL BE RATHER
LIGHT. LOWS TONIGHT SHOULD BE IN THE MID 40S NW...TO MID 50S
SE...FOLLOWED BY HIGHS TUESDAY IN THE LOW 50S N AND W...TO LOW 60S
SE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
THE FRONT EVENTUALLY WILL BECOME STALLED SOUTH OF THE AREA BY
TUESDAY NIGHT AND WEDNESDAY. IN THE INTERIM, EXPECT CLEARING ON
TUESDAY WITH HIGH PRESSURE BUILDING IN FROM THE WEST. LINGERING
SHRAS ACROSS SE COASTAL PLAIN QUICKLY YIELD TO SEASONABLY COOL AND
DRY CONDITIONS BY AFTN. WINDS TURN AROUND TO THE NORTH AND REMAIN
RATHER LIGHT THROUGH THE DAY. HIGHS GENERALLY IN THE 50S UNDER A
PARTLY TO MOSTLY CLOUDY SKY
MODELS APPEAR IN A BIT MORE AGREEMENT WITH DEPICTING A WAVE OF
LOW PRESSURE THAT DEVELOPS ALONG THE STALLED BOUNDARY TO THE SOUTH
ON TUESDAY, BUT STILL SOME DISAGREEMENT WRT ORIENTATION OF PCPN
TUESDAY NIGHT AND WEDNESDAY. ECMWF KEEPS MUCH OF THIS ACTIVITY
WELL TO OUR SOUTH, WITH THE NAM BRINGING LIGHT PCPN AS FAR NORTH
AS RIC. GFS/SREF STILL APPEARS TO BE ACCEPTABLE MIDDLE GROUND
SOLUTION, BRINGING SOME LIGHT PCPN ACROS SOUTHERN TIER OF COUNTIES
LATE TUE-WED. CONTINUED INHERITED TREND WITH INCREASING CLOUDS
TUESDAY NIGHT/WED ACROSS THE SOUTHEAST, WITH RAIN CHCS FOR LATE
TUE INTO WED STILL LOOKING GOOD (LOW QPF ONCE AGAIN). LOW
TEMPERATURES TUESDAY NIGHT ARE FORECAST TO BE IN THE MID 30S
N...TO LOW TO MID 40S SE. HIGHS WEDNESDAY IN THE MID 40S TO LOW
50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
FNTL BNDRY/ASSOCD MSTR
SLO TO EXIT THE CST WED NGT. AFT THAT...HI PRES BUILDS INTO THE
MDATLC RGN FM THU THROUGH FRI...THEN WEAKENS INTO THE NEXT WKND.
UNCERTAINTY EXISTS NEXT SAT/SUN WRT PTNTL BKDR CDFNT ENTERING THE
RGN FM THE N...AND PSBL ARRIVAL OF LO PRES FM THE W.
LO POPS WED NGT...GIVING WAY TO DRY WX (AND POPS AOB 14%) THU INTO
SAT. WILL BRING A GRADUAL INCRS IN CLDNS AND POPS FM SAT THROUGH
SUN. TEMPS WILL AVG OUT NR SEASONABLE LVLS THROUGH THE PD.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
A WARM FRONT DRAPED ACROSS CTRL VA IS ALLOWING AREAS OF FOG AND
VERY LOW CIGS (200-500 FT AGL) TO PLAGUE THE REGION THIS MORNING.
TAF SITES KRIC AND KPHF WILL BE THE MOST SUSCEPTIBLE TO THESE
CONDITIONS THRU AT LEAST 10/1300Z. MEANWHILE...A DISTURBANCE ALONG
THE NC COAST WILL MOVE NNE AND SPREAD LIGHT RAIN SHOWERS OVER
NE NC...FAR SE VA...AND THE MD/VA LOWER ERN SHORE THIS MORNING
THRU EARLY AFTN BEFORE PUSHING NE AND AWAY FROM THE MID ATLANTIC
COAST. SOME CLEARING...OR AT LEAST HIGHER CIGS AND VIS...ARE
ANTICIPATED DURING THE AFTN AS THE REGION SITS WITHIN THE WARM
SECTOR AHEAD OF AN APPROACHING COLD FRONT TO THE WEST. EXPECT
BREEZY SOUTH WINDS TO DEVELOP BY EARLY AFTN AND PERSIST INTO THIS
EVENING...BECOMING GUSTY AT TIMES (15-20KT). THE COLD FRONT IS
FORECAST TO CROSS THE AREA TONIGHT INTO TUESDAY MORNING. THE BEST
RAINFALL WILL OCCUR RIGHT ALONG THE FRONT LATE THIS EVENING...
GRADUALLY DIMINISHING IN INTENSITY OVERNIGHT AS ITS ENERGY GETS
SHEARED APART WHILE IT TRACKS TWD THE COAST. CIGS ARE ESTIMATED TO
BE 2-3KFT AND VIS SHOULD BE NO LOWER THAN 3-4SM UNDER HEAVIER
AREAS OF RAINFALL.
LINGERING PRECIP IS POSSIBLE ALONG THE IMMEDIATE MID ATLANTIC
COAST TUESDAY MORNING WITH CONDITIONS IMPROVING THROUGHOUT THE
DAY. A SECONDARY LOW PRESSURE SYSTEM WILL TRACK UP THE COAST AND
BRING STEADY STRATIFORM PRECIP MAINLY TO AREAS SE OF A LINE FROM
KSBY-KRIC-KDAN LATE TUESDAY NIGHT INTO WEDNESDAY. THIS SYSTEM HAS
THE POTENTIAL TO RAPIDLY DETERIORATE CIGS/VIS AT ALL TAF SITES
DURING THIS TIME.
&&
.MARINE...
A WARM FRONT WILL LIFT NORTH AS WARM FRONT AS A COLD FRONT
APPROACHES FROM THE WEST TODAY. S WINDS WILL GRADUALLY INCREASE AND
VEER TO THE SSW-SW THROUGH THE MORNING AND BECOME BREEZY/GUSTY BY
EARLY AFTN. SUSTAINED WINDS WILL AVERAGE 10-15 KT WITH GUSTS OF
15-20 KT OVER ALL AREA WATERS. THEREFORE...SCA FLAGS HAVE BEEN
RAISED FOR ERN VA RIVERS AND CURRITUCK SOUND BEGINNING AT NOON AND
ENDING AROUND MIDNIGHT. NRN COASTAL WATERS WILL SEE THEIR INCREASE
IN WIND SPEEDS LATE AFTN/EARLY EVENING WITH SUSTAINED 20 KT AND
GUSTS OF 25-30 KT AT TIMES. OVERALL...MAIN SUITE OF SCA HEADLINES
ISSUED ON SUNDAY REMAIN INTACT REGARDING TIMING...WIND
SPEEDS/GUSTS...AND WAVES/SEAS (3-4 FT BAY/4-5 FT OCEAN).
THE COLD FRONT CROSSES THE WATERS MONDAY NIGHT...FOLLOWED BY LLVL
SURGE AND MODERATE PROBABILITIES FOR SCA SPEEDS AS WINDS BECOME NNW
AFTER MIDNIGHT. CONDITIONS WILL BE SLOW TO IMPROVE DURING TUESDAY AS
THE FRONT STALLS JUST OFF THE COASTAL CAROLINAS AND WEAK HIGH
PRESSURE BUILDS IN THE NRN MID ATLANTIC REGION. EXPECT A PERIOD OF
NNE WINDS FROM TUE NIGHT INTO WED NIGHT AS A SECONDARY SFC LOW
PRESSURE DEVELOPS/TRACKS NE ALONG THE STALLED FRONT. TIGHT
TEMPERATURE DIFFERENCES WILL LIKELY RESULT IN A TIGHT PRESSURE
GRADIENT AND SPEEDS/WAVES/SEAS ARE ANTICIPATED TO INCREASE INTO SCA
THRESHOLDS...ESPECIALLY THE SRN PORTION OF THE BAY/OCEAN WATERS
TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE IS POISED TO RETURN LATE
IN THE WEEK WHICH WILL GREATLY IMPROVE MARINE WX CONDITIONS HEADING
INTO THE WEEKEND.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 AM EST
TUESDAY FOR ANZ633-635>637.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR ANZ632-634.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
TUESDAY FOR ANZ630-631-638.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO NOON EST
TUESDAY FOR ANZ650-652-654.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAS/MAM
SHORT TERM...AJZ/MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...ALB
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
656 AM EST MON DEC 10 2012
.SYNOPSIS...
A WARM FRONT LIFTS VERY SLOWLY NORTH THROUGH THE MID ATLANTIC THIS
MORNING. A COLD FRONT APPROACHES FROM THE WEST THROUGH THIS
EVENING...BEFORE PUSHING ACROSS THE AREA LATE TONIGHT INTO EARLY
TUESDAY. LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE FRONT
TUESDAY NIGHT AND TRACKS OFF THE COAST WEDNESDAY. HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS SHOWS LOW PRESSURE OVER EASTERN GREAT LAKES
THIS MORNING, WITH WEAK QUASI-STATIONARY FRONT STILL DRAPED OVER
INTERIOR EASTERN SHORE...ACROSS INTO SOUTH CENTRAL VA AND BACK
INTO WESTERN PA/E OHIO. VISIBILITIES HAVE BEGUN TO IMPROVE AS
EXPECTED ACROSS INTERIOR NC AND ALONG I-85 CORRIDOR. WILL BE
DROPPING DENSE FOG ADVISORY WITH MORNING PACKAGE ISSUANCE OVER
SOUTHERN PORTIONS OF THE AREA. DO EXPECT VISIBILITIES TO CONTINUE
TO IMPROVE W/CONTINUED WAA, BUT FOR NOW WILL HOLD ONTO MOST
LOCATIONS ALONG AND NORTH OF A FARMVILLE- RICHMOND- WALLOPS LINE.
LATEST SUBJECTIVE UPPER AIR ANALYSIS SHOWS POSITIVELY TILTED UPPER
TROUGH AXIS EXTENDING FROM THE UPPER MID WEST BACK INTO THE
CENTRAL HIGH PLAINS. BROAD, MOIST SW FLOW AHEAD OF THIS FEATURE
FROM THE SOUTHEASTERN CONUS UP INTO THE MID-ATLANTIC REGION. SOME
SHRAS NOTED ON REGIONAL RADAR MOSAIC IN ASSOCIATION WITH WEAK
SHORTWAVE TROUGH PUSHING ACROSS THE CAROLINA COASTAL PLAIN. MODELS
SEEM TO BE HAVING TROUBLE WITH THIS FEATURE, SO HAVE USED A BLEND
OF RUC AND SREF IN QUICKLY SCOOTING THIS WAVE OFFSHORE BY MID TO
LATE MORNING, WITH A FEW SHOWERS PUSHING INTO FAR EASTERN ZONES.
QPF LOOKING RATHER LIGHT...ON THE ORDER OF A FEW HUNDREDTHS TO A
TENTH OF AN INCH.
NORTHERN STREAM TROUGH LIFTS NORTH OF THE GREAT LAKES TODAY, AS
NEXT SOUTHERN PLAINS DAMPENS AS IT LIFTS FROM SOUTHERN PLAINS
TOWARDS THE OHIO VALLEY BY TONIGHT. AS THIS HAPPENS, SFC LOW OVER
THE EASTERN GRT LAKES WILL LIFT INTO QUEBEC WITH ATTENDANT SFC
COLD FRONT SWEEPING EASTWARD BY TONIGHT. AS IS USUALLY THE CASE,
MODELS APPEAR TOO AGGRESSIVE THIS MORNING IN PUSHING STALLED
FRONTAL BOUNDARY NORTH THIS MORNING, AND TRYING TO CLEAR OUT LOW
CLOUDS. WILL CONTINUE WITH PARTLY TO MOSTLY CLOUDY WORDING THROUGH
THE DAY, W/ HIGHS IN THE MID 60S TO LOW 70S, WITH A FEW MID 70S
POSSIBLE GIVEN PRESENT TEMPERATURES ALREADY IN THE L-M 60S ACROSS
SE VA/NE NC.
FORCING FOR ASCENT APPEARS RATHER ANEMIC THROUGH MUCH OF THE DAY
AND DESPITE MILD TEMPS AND LLVL MOISTURE, FORECAST SOUNDINGS
INDICATE DESTABILIZATION WILL BE DIFFICULT GIVEN SIGNIFICANT CLOUD
COVER THROUGH MOST OF THE DAY. THUS, EXPECT MOST OF THE DAY TO BE
DRY OVER THE AREA. DO INCREASE RAIN CHANCES OVER THE FAR NW BY THE
LATE AFTERNOON AS FRONT APPROACHES FROM THE WEST.
AS MENTIONED EARLIER, THE UPPER TROUGH WILL DAMPEN/WEAKEN AS IT
PUSHES ACROSS THE OHIO VALLEY INTO THE NORTHERN MID ATLANTIC
TONIGHT INTO EARLY TUESDAY, DRAGGING THE COLD FRONT ACROSS THE
CWA TONIGHT AND OFF THE COAST EARLY TUESDAY MORNING. HIGH END CHC
TO LIKELY POPS (50-60%) WILL BE MAINTAINED WITH THE FRONTAL
PASSAGE TONIGHT ACROSS THE WEST, ALTHOUGH QPF WILL BE RATHER
LIGHT. LOWS TONIGHT SHOULD BE IN THE MID 40S NW...TO MID 50S
SE...FOLLOWED BY HIGHS TUESDAY IN THE LOW 50S N AND W...TO LOW 60S
SE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
THE FRONT EVENTUALLY WILL BECOME STALLED SOUTH OF THE AREA BY
TUESDAY NIGHT AND WEDNESDAY. IN THE INTERIM, EXPECT CLEARING ON
TUESDAY WITH HIGH PRESSURE BUILDING IN FROM THE WEST. LINGERING
SHRAS ACROSS SE COASTAL PLAIN QUICKLY YIELD TO SEASONABLY COOL AND
DRY CONDITIONS BY AFTN. WINDS TURN AROUND TO THE NORTH AND REMAIN
RATHER LIGHT THROUGH THE DAY. HIGHS GENERALLY IN THE 50S UNDER A
PARTLY TO MOSTLY CLOUDY SKY
MODELS APPEAR IN A BIT MORE AGREEMENT WITH DEPICTING A WAVE OF
LOW PRESSURE THAT DEVELOPS ALONG THE STALLED BOUNDARY TO THE SOUTH
ON TUESDAY, BUT STILL SOME DISAGREEMENT WRT ORIENTATION OF PCPN
TUESDAY NIGHT AND WEDNESDAY. ECMWF KEEPS MUCH OF THIS ACTIVITY
WELL TO OUR SOUTH, WITH THE NAM BRINGING LIGHT PCPN AS FAR NORTH
AS RIC. GFS/SREF STILL APPEARS TO BE ACCEPTABLE MIDDLE GROUND
SOLUTION, BRINGING SOME LIGHT PCPN ACROS SOUTHERN TIER OF COUNTIES
LATE TUE-WED. CONTINUED INHERITED TREND WITH INCREASING CLOUDS
TUESDAY NIGHT/WED ACROSS THE SOUTHEAST, WITH RAIN CHCS FOR LATE
TUE INTO WED STILL LOOKING GOOD (LOW QPF ONCE AGAIN). LOW
TEMPERATURES TUESDAY NIGHT ARE FORECAST TO BE IN THE MID 30S
N...TO LOW TO MID 40S SE. HIGHS WEDNESDAY IN THE MID 40S TO LOW
50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
FNTL BNDRY/ASSOCD MSTR
SLO TO EXIT THE CST WED NGT. AFT THAT...HI PRES BUILDS INTO THE
MDATLC RGN FM THU THROUGH FRI...THEN WEAKENS INTO THE NEXT WKND.
UNCERTAINTY EXISTS NEXT SAT/SUN WRT PTNTL BKDR CDFNT ENTERING THE
RGN FM THE N...AND PSBL ARRIVAL OF LO PRES FM THE W.
LO POPS WED NGT...GIVING WAY TO DRY WX (AND POPS AOB 14%) THU INTO
SAT. WILL BRING A GRADUAL INCRS IN CLDNS AND POPS FM SAT THROUGH
SUN. TEMPS WILL AVG OUT NR SEASONABLE LVLS THROUGH THE PD.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A WARM FRONT DRAPED ACROSS CTRL VA IS ALLOWING AREAS OF FOG AND
VERY LOW CIGS (200-500 FT AGL) TO PLAGUE THE REGION THIS MORNING.
TAF SITES KRIC AND KPHF WILL BE THE MOST SUSCEPTIBLE TO THESE
CONDITIONS THRU AT LEAST 10/1300Z. MEANWHILE...A DISTURBANCE ALONG
THE NC COAST WILL MOVE NNE AND SPREAD LIGHT RAIN SHOWERS OVER
NE NC...FAR SE VA...AND THE MD/VA LOWER ERN SHORE THIS MORNING
THRU EARLY AFTN BEFORE PUSHING NE AND AWAY FROM THE MID ATLANTIC
COAST. SOME CLEARING...OR AT LEAST HIGHER CIGS AND VIS...ARE
ANTICIPATED DURING THE AFTN AS THE REGION SITS WITHIN THE WARM
SECTOR AHEAD OF AN APPROACHING COLD FRONT TO THE WEST. EXPECT
BREEZY SOUTH WINDS TO DEVELOP BY EARLY AFTN AND PERSIST INTO THIS
EVENING...BECOMING GUSTY AT TIMES (15-20KT). THE COLD FRONT IS
FORECAST TO CROSS THE AREA TONIGHT INTO TUESDAY MORNING. THE BEST
RAINFALL WILL OCCUR RIGHT ALONG THE FRONT LATE THIS EVENING...
GRADUALLY DIMINISHING IN INTENSITY OVERNIGHT AS ITS ENERGY GETS
SHEARED APART WHILE IT TRACKS TWD THE COAST. CIGS ARE ESTIMATED TO
BE 2-3KFT AND VIS SHOULD BE NO LOWER THAN 3-4SM UNDER HEAVIER
AREAS OF RAINFALL.
LINGERING PRECIP IS POSSIBLE ALONG THE IMMEDIATE MID ATLANTIC
COAST TUESDAY MORNING WITH CONDITIONS IMPROVING THROUGHOUT THE
DAY. A SECONDARY LOW PRESSURE SYSTEM WILL TRACK UP THE COAST AND
BRING STEADY STRATIFORM PRECIP MAINLY TO AREAS SE OF A LINE FROM
KSBY-KRIC-KDAN LATE TUESDAY NIGHT INTO WEDNESDAY. THIS SYSTEM HAS
THE POTENTIAL TO RAPIDLY DETERIORATE CIGS/VIS AT ALL TAF SITES
DURING THIS TIME.
&&
.MARINE...
A WARM FRONT WILL LIFT NORTH AS WARM FRONT AS A COLD FRONT
APPROACHES FROM THE WEST TODAY. S WINDS WILL GRADUALLY INCREASE AND
VEER TO THE SSW-SW THROUGH THE MORNING AND BECOME BREEZY/GUSTY BY
EARLY AFTN. SUSTAINED WINDS WILL AVERAGE 10-15 KT WITH GUSTS OF
15-20 KT OVER ALL AREA WATERS. THEREFORE...SCA FLAGS HAVE BEEN
RAISED FOR ERN VA RIVERS AND CURRITUCK SOUND BEGINNING AT NOON AND
ENDING AROUND MIDNIGHT. NRN COASTAL WATERS WILL SEE THEIR INCREASE
IN WIND SPEEDS LATE AFTN/EARLY EVENING WITH SUSTAINED 20 KT AND
GUSTS OF 25-30 KT AT TIMES. OVERALL...MAIN SUITE OF SCA HEADLINES
ISSUED ON SUNDAY REMAIN INTACT REGARDING TIMING...WIND
SPEEDS/GUSTS...AND WAVES/SEAS (3-4 FT BAY/4-5 FT OCEAN).
THE COLD FRONT CROSSES THE WATERS MONDAY NIGHT...FOLLOWED BY LLVL
SURGE AND MODERATE PROBABILITIES FOR SCA SPEEDS AS WINDS BECOME NNW
AFTER MIDNIGHT. CONDITIONS WILL BE SLOW TO IMPROVE DURING TUESDAY AS
THE FRONT STALLS JUST OFF THE COASTAL CAROLINAS AND WEAK HIGH
PRESSURE BUILDS IN THE NRN MID ATLANTIC REGION. EXPECT A PERIOD OF
NNE WINDS FROM TUE NIGHT INTO WED NIGHT AS A SECONDARY SFC LOW
PRESSURE DEVELOPS/TRACKS NE ALONG THE STALLED FRONT. TIGHT
TEMPERATURE DIFFERENCES WILL LIKELY RESULT IN A TIGHT PRESSURE
GRADIENT AND SPEEDS/WAVES/SEAS ARE ANTICIPATED TO INCREASE INTO SCA
THRESHOLDS...ESPECIALLY THE SRN PORTION OF THE BAY/OCEAN WATERS
TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE IS POISED TO RETURN LATE
IN THE WEEK WHICH WILL GREATLY IMPROVE MARINE WX CONDITIONS HEADING
INTO THE WEEKEND.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ048-049-
060>064-067>074-083.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO NOON EST
TUESDAY FOR ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 AM EST
TUESDAY FOR ANZ633-635>637.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR ANZ632-634.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
TUESDAY FOR ANZ630-631-638.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...ALB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
709 AM EST MON DEC 10 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 546 AM EST MON DEC 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM NW ONTARIO INTO THE SRN PLAINS. THE SHORTWAVE TROUGH THAT
BROUGHT HEAVY SNOW TO THE UPPER MS VALLEY SUNDAY HAS
SHEARED/WEAKENED AND LIFTED QUICKLY TO THE EAST OF UPPER MICHIGAN.
CYCLONIC NNE LOW LEVEL FLOW COMBINED WITH ABUNDANT 850-700 MB
MOISTURE AND 850 MB TEMPS TO ARUOND -11C SUPPORTED LAKE EFFECT SNOW
INTO N CNTRL UPPER MI. 850-700 MB FGEN AHEAD OF AN 850-700 MB
THERMAL TROUGH INTO NRN MN ALSO SUPPORTED SOME LIGHT SNOW OVER NE MN
AND HELPED ENHANCE THE LES INTO FAR NW WI. SO FAR...LAND BREEZE AND
LAKE INDUCED TROUGHING HAS KEPT THE MAIN LES BANDS WEST OF IWD
THROUGH 10Z.
MAIN FCST CONCERNS ARE LES TRENDS AND SNOW AMOUNTS.
TODAY...
SATELLITE TRENDS AND MODELS SUGGEST THAT ANY LINGERING
SYNOPTIC SCALE LIFT WILL DEPART EARLY TODAY WITH THE 850-700 MB
MOISUTRE ALSO THINNING OUT BY THIS AFTERNOON ALONG WITH ONLY A
GRADUAL BACKING TREND IN THE LOW LEVEL WIND FROM NE TO NORTH. THIS
SHOULD KEEP THE LES GOING INTO NORTH CENTRAL MICHIGAN GOING THIS
MORNING WITH LIGHT TO MODERATE SNOWFALL RATES...ESPECIALLY INTO
UPSLOPE FLOW LOCATIONS. THIS SHOULD PRODUCE AN ADDITIONAL 1 TO 3
INCHES OF SNOW MAINLY IN THE HIGHER TERRAIN LOCATIONS OF MARQUETTE
COUNTY FROM THE HURON MOUNTAINS TO NEGAUNEE/ISHPMEMING AND GWINN.
HIGH RES MODELS HAVE BEEN CONSISTENT IN GRADUALLY SHIFTING THE AXIS
OF LEVEL CONV AND BRINGING THE LES BANDS INTO WESTERN GOGEBIC COUNTY
BY AROUND 12Z. EVEN THOUGH THERE MAY SOME DELAY TO THE ONSET OF
HEAVIER SNOW IF THE TROUGH MOVEMENT IS SLOWER THAN EXPECTED...A
PERIOD OF MODERATE TO HEAVY SNOW VCNTY IWD COULD BRING AT LEAST 1 TO
4 INCHES OF SNOW. HOWEVER...CONFIDENCE IN THE TIMING/DURATION OF THE
HEAVIER BAND IS STILL LIMITED. AS A WEAK RIDGE BUILDS TOWARD THE AREA
THIS AFTERNOON AND WINDS/CONV WEAKENS...THE SNOW SHOULD DIMINISH OVER
BOTH THE WEST AND N CNTRL UPPER MI.
TONIGHT...
A A WEAK SHORTWAVE AND SFC TROUGH REFLECTION WILL APPROACH
THE AREA BRINGING A SHIFT TO SW TO S WINDS. THIS SHOULD PUSH ANY
REMANING LES FROM LAKE SUPERIOR OFFSHORE DURING THE EVENING. WITH
THE VERY WEAK WIND FIELDS...THERE IS THE POSSIBILITY THAT A
SHORELINE PARALLEL OR MESO-LOW BAND MAY BRUSH THE WEST UPPER MI
SHORELINE. A WEAK BAND 700-300 MB QVECTOR CONV AND ISENTROPIC LIFT
AHEAD OF THIS FEATURE MAY SUPPORT SOME LIGHT SNOW INTO WEST UPPER
MICHIGAN. HOWEVER...ONLY SLIGHT CHANCE POPS WERE MENTIONED.
INCREASING LOW LEVEL CONV SRLY FLOW OFF OF LAKE MICHIGAN MAY ALSO
BRING AN LES BAND INTO THE SE CWA LATE BUT SHOULD HOLD OFF MAINLY
UNTIL TUES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 546 AM EST MON DEC 10 2012
SURFACE RIDGE AXIS WILL BE EAST OF THE AREA BY TUESDAY MORNING. AS
NEXT UPPER TROUGH MOVES INTO WESTERN ONTARIO WITH ASSOCIATED WEAK
SURFACE LOW WINDS WILL BECOME SOUTHERLY ACROSS THE ENTIRE AREA. 85H
TEMPS WILL REMAIN LOW ENOUGH...-10 TO -12...TO SUPPORT A LAKE EFFECT
SNOW BAND OFF OF LAKE MICHIGAN INTO THE EASTERN U.P. WINDS WILL
SLOWLY BUT STEADILY VEER THROUGH THE DAY ALLOWING THE BAND TO BE
TRANSIENT FROM WEST TO EAST WHICH SHOULD LIMIT SNOWFALL AMOUNTS OVER
EASTERN SCHOOLCRAFT AND LUCE COUNTIES IN THE 1 TO AS MUCH AS 3 INCH
RANGE.
AS SURFACE LOW MOVES ACROSS ONTARIO...SURFACE TROUGH WILL CROSS LAKE
SUPERIOR ALLOWING WINDS TO BECOME WESTERLY AND 85H TEMPS TO FALL TO
-14 BRIEFLY OVER WESTERN LAKE SUPERIOR. EXPECT SOME LAKE EFFECT SNOW
TO AFFECT THE KEWEENAW PENINSULA TUE EVENING/TUE NIGHT BEFORE WARM
ADVECTION REGIME SETS IN ACROSS THE WESTERN LAKE.
SOUTHERLY WINDS WILL RETURN FOR WEDNESDAY INTO THURSDAY AS ANOTHER
WEAK DISTURBANCE SKIRTS BY JUST NORTH OF THE AREA. ANY FORCING FOR
PRECIPITATION SHOULD REMAIN OVER NORTHERN LAKE SUPERIOR INTO
ONTARIO. 85H TEMPS FOR WEDNESDAY AND THURSDAY WILL BE IN THE 0 TO -4
RANGE RESULTING IN DAYTIME TEMPERATURES A FEW DEGREES ABOVE NORMAL.
VERY LITTLE CONFIDENCE IN THE FORECAST BEYOND THURSDAY WITH MEDIUM
RANGE MODELS SHOWING LARGE SCALE DISCREPANCIES. ECMWF HAS BEEN
CONSISTENT IN HINTING AT A POTENTIAL STORM SYSTEM DEVELOPING OVER
THE PLAINS AND LIFTING INTO THE GREAT LAKES OVER THE WEEKEND WITH
THE GFS SHOWING HIGH PRESSURE OVER THE GREAT LAKES NEXT WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 702 AM EST MON DEC 10 2012
EXPECT PREDOMINANT MVFR CONDITIONS TO DOMINATE THIS FCST PERIOD AT
ALL 3 TAF SITES WITH LINGERING LOW LEVEL MOISTURE SLOWLY WEAKENING
CYCLONIC NNE FLOW UNDER SUBSIDENCE LEFT IN THE WAKE OF DEPARTING
DISTURBANCE. THE MAJOR EXCEPTION WILL BE A PERIOD OF IFR CONDITIONS
THIS MORNING UNDER SOME HEAVIER LK EFFECT SHSN THAT WILL IMPACT IWD
AND SAW...LOCATIONS FAVORED BY THE EXPECTED NNE WIND. CONDITIONS MAY
IMPROVE TO VFR THIS EVENING AS WINDS BECOME SRLY AHEAD OF A WEAK
TROUGH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 546 AM EST MON DEC 10 2012
NORTHERLY WINDS OF 20 TO 30 KNOTS EARLY TODAY ARE EXPECTED TO
DIMINISH AS A TROUGH TO THE SOUTH OF UPPER MICHIGAN GRADUALLY
WEAKENS AND SHIFTS TO THE SOUTHEAST. BEHIND THIS FEATURE...A SERIES
OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST
OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ005-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
550 AM EST MON DEC 10 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 546 AM EST MON DEC 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM NW ONTARIO INTO THE SRN PLAINS. THE SHORTWAVE TROUGH THAT
BROUGHT HEAVY SNOW TO THE UPPER MS VALLEY SUNDAY HAS
SHEARED/WEAKENED AND LIFTED QUICKLY TO THE EAST OF UPPER MICHIGAN.
CYCLONIC NNE LOW LEVEL FLOW COMBINED WITH ABUNDANT 850-700 MB
MOISTURE AND 850 MB TEMPS TO ARUOND -11C SUPPORTED LAKE EFFECT SNOW
INTO N CNTRL UPPER MI. 850-700 MB FGEN AHEAD OF AN 850-700 MB
THERMAL TROUGH INTO NRN MN ALSO SUPPORTED SOME LIGHT SNOW OVER NE MN
AND HELPED ENHANCE THE LES INTO FAR NW WI. SO FAR...LAND BREEZE AND
LAKE INDUCED TROUGHING HAS KEPT THE MAIN LES BANDS WEST OF IWD
THROUGH 10Z.
MAIN FCST CONCERNS ARE LES TRENDS AND SNOW AMOUNTS.
TODAY...
SATELLITE TRENDS AND MODELS SUGGEST THAT ANY LINGERING
SYNOPTIC SCALE LIFT WILL DEPART EARLY TODAY WITH THE 850-700 MB
MOISUTRE ALSO THINNING OUT BY THIS AFTERNOON ALONG WITH ONLY A
GRADUAL BACKING TREND IN THE LOW LEVEL WIND FROM NE TO NORTH. THIS
SHOULD KEEP THE LES GOING INTO NORTH CENTRAL MICHIGAN GOING THIS
MORNING WITH LIGHT TO MODERATE SNOWFALL RATES...ESPECIALLY INTO
UPSLOPE FLOW LOCATIONS. THIS SHOULD PRODUCE AN ADDITIONAL 1 TO 3
INCHES OF SNOW MAINLY IN THE HIGHER TERRAIN LOCATIONS OF MARQUETTE
COUNTY FROM THE HURON MOUNTAINS TO NEGAUNEE/ISHPMEMING AND GWINN.
HIGH RES MODELS HAVE BEEN CONSISTENT IN GRADUALLY SHIFTING THE AXIS
OF LEVEL CONV AND BRINGING THE LES BANDS INTO WESTERN GOGEBIC COUNTY
BY AROUND 12Z. EVEN THOUGH THERE MAY SOME DELAY TO THE ONSET OF
HEAVIER SNOW IF THE TROUGH MOVEMENT IS SLOWER THAN EXPECTED...A
PERIOD OF MODERATE TO HEAVY SNOW VCNTY IWD COULD BRING AT LEAST 1 TO
4 INCHES OF SNOW. HOWEVER...CONFIDENCE IN THE TIMING/DURATION OF THE
HEAVIER BAND IS STILL LIMITED. AS A WEAK RIDGE BUILDS TOWARD THE AREA
THIS AFTERNOON AND WINDS/CONV WEAKENS...THE SNOW SHOULD DIMINISH OVER
BOTH THE WEST AND N CNTRL UPPER MI.
TONIGHT...
A A WEAK SHORTWAVE AND SFC TROUGH REFLECTION WILL APPROACH
THE AREA BRINGING A SHIFT TO SW TO S WINDS. THIS SHOULD PUSH ANY
REMANING LES FROM LAKE SUPERIOR OFFSHORE DURING THE EVENING. WITH
THE VERY WEAK WIND FIELDS...THERE IS THE POSSIBILITY THAT A
SHORELINE PARALLEL OR MESO-LOW BAND MAY BRUSH THE WEST UPPER MI
SHORELINE. A WEAK BAND 700-300 MB QVECTOR CONV AND ISENTROPIC LIFT
AHEAD OF THIS FEATURE MAY SUPPORT SOME LIGHT SNOW INTO WEST UPPER
MICHIGAN. HOWEVER...ONLY SLIGHT CHANCE POPS WERE MENTIONED.
INCREASING LOW LEVEL CONV SRLY FLOW OFF OF LAKE MICHIGAN MAY ALSO
BRING AN LES BAND INTO THE SE CWA LATE BUT SHOULD HOLD OFF MAINLY
UNTIL TUES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 546 AM EST MON DEC 10 2012
SURFACE RIDGE AXIS WILL BE EAST OF THE AREA BY TUESDAY MORNING. AS
NEXT UPPER TROUGH MOVES INTO WESTERN ONTARIO WITH ASSOCIATED WEAK
SURFACE LOW WINDS WILL BECOME SOUTHERLY ACROSS THE ENTIRE AREA. 85H
TEMPS WILL REMAIN LOW ENOUGH...-10 TO -12...TO SUPPORT A LAKE EFFECT
SNOW BAND OFF OF LAKE MICHIGAN INTO THE EASTERN U.P. WINDS WILL
SLOWLY BUT STEADILY VEER THROUGH THE DAY ALLOWING THE BAND TO BE
TRANSIENT FROM WEST TO EAST WHICH SHOULD LIMIT SNOWFALL AMOUNTS OVER
EASTERN SCHOOLCRAFT AND LUCE COUNTIES IN THE 1 TO AS MUCH AS 3 INCH
RANGE.
AS SURFACE LOW MOVES ACROSS ONTARIO...SURFACE TROUGH WILL CROSS LAKE
SUPERIOR ALLOWING WINDS TO BECOME WESTERLY AND 85H TEMPS TO FALL TO
-14 BRIEFLY OVER WESTERN LAKE SUPERIOR. EXPECT SOME LAKE EFFECT SNOW
TO AFFECT THE KEWEENAW PENINSULA TUE EVENING/TUE NIGHT BEFORE WARM
ADVECTION REGIME SETS IN ACROSS THE WESTERN LAKE.
SOUTHERLY WINDS WILL RETURN FOR WEDNESDAY INTO THURSDAY AS ANOTHER
WEAK DISTURBANCE SKIRTS BY JUST NORTH OF THE AREA. ANY FORCING FOR
PRECIPITATION SHOULD REMAIN OVER NORTHERN LAKE SUPERIOR INTO
ONTARIO. 85H TEMPS FOR WEDNESDAY AND THURSDAY WILL BE IN THE 0 TO -4
RANGE RESULTING IN DAYTIME TEMPERATURES A FEW DEGREES ABOVE NORMAL.
VERY LITTLE CONFIDENCE IN THE FORECAST BEYOND THURSDAY WITH MEDIUM
RANGE MODELS SHOWING LARGE SCALE DISCREPANCIES. ECMWF HAS BEEN
CONSISTENT IN HINTING AT A POTENTIAL STORM SYSTEM DEVELOPING OVER
THE PLAINS AND LIFTING INTO THE GREAT LAKES OVER THE WEEKEND WITH
THE GFS SHOWING HIGH PRESSURE OVER THE GREAT LAKES NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 142 AM EST MON DEC 10 2012
EXPECT PREDOMINANT MVFR CONDITIONS TO DOMINATE THIS FCST PERIOD AT
ALL 3 TAF SITES WITH LINGERING LLVL MSTR/SLOWLY WEAKENING CYC NNE
FLOW UNDER SUBSIDENCE LEFT IN THE WAKE OF DEPARTING DISTURBANCE
RESPONSIBLE FOR SN ON SUN EVNG. THE MAJOR EXCEPTION WL BE A PERIOD
OF IFR CONDITIONS THIS MRNG UNDER SOME HEAVIER LK EFFECT SHSN THAT
WL IMPACT IWD AND SAW...LOCATIONS FAVORED BY THE EXPECTED NNE WIND.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 546 AM EST MON DEC 10 2012
NORTHERLY WINDS OF 20 TO 30 KNOTS EARLY TODAY ARE EXPECTED TO
DIMINISH AS A TROUGH TO THE SOUTH OF UPPER MICHIGAN GRADUALLY
WEAKENS AND SHIFTS TO THE SOUTHEAST. BEHIND THIS FEATURE...A SERIES
OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST
OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ005-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
645 AM EST MON DEC 10 2012
.SYNOPSIS...
SOME SHOWERS WILL LINGER ACROSS PARTS OF THE AREA INTO THIS
AFTERNOON AS A COLD FRONT CONTINUES TO PUSH OFF TO THE EAST.
COLDER AIR FILTERING INTO THE AREA BEHIND THE FRONT WILL LEAD TO
FALLING TEMPERATURES THROUGH THIS AFTERNOON. HIGH PRESSURE WILL
BUILD INTO THE REGION THROUGH MID WEEK...LEADING TO DRIER BUT
COOLER CONDITIONS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT EVIDENT ON RADAR PUSHING SLOWLY EAST...CURRENTLY
SITUATED RIGHT ALONG INTERSTATE 71. WIDESPREAD SHOWERS ARE
CONTINUING OUT AHEAD OF THE FRONT ACROSS SOUTHEASTERN PORTIONS OF
OUR FA. THE FRONT WILL CONTINUE TO PUSH EAST THROUGH THIS
AFTERNOON...BUT THE NAM AND RAP ARE BOTH INDICATING SOME
ADDITIONAL PCPN OVERRUNNING THE FRONT BACK UP ACROSS PORTIONS OF
OUR FA THROUGH THIS AFTERNOON. THE GFS AND ECMWF ARE NOT QUITE AS
AGGRESSIVE WITH THIS BUT THEY TOO ARE AT LEAST HINTING AT THE
POSSIBILITY OF IT. AS A RESULT...WILL ALLOW FOR PCPN TO LINGER
BACK FARTHER TO THE WEST THEN CURRENTLY INDICATED BY THE RADAR
TRENDS. DUE TO THE MODEL DIFFERENCES...THE WESTERN EXTENT OF THIS
IS IN DOUBT THOUGH AND HAVE GENERALLY TRENDED CLOSE TO THE 03Z
SREF WHICH KEEPS LIKELY OR HIGHER POPS PRETTY CLOSE TO ONGOING
PCPN. WILL THEN TAPER BACK TO CHANCE POPS HEADING BACK THE
NORTHWEST TO ACCOUNT FOR THE UNCERTAINTY. DEVELOPING CAA BEHIND
THE FRONT WILL LIKELY ALLOW FOR SOME FALLING TEMPERATURES THROUGH
THIS AFTERNOON. IF PCPN EXTENDS FAR ENOUGH BACK TO THE WEST...WE
COULD END UP WITH A RAIN SNOW MIX ALONG THE WESTERN FRINGE OF THE
PCPN BY LATER THIS AFTERNOON AS THE LOW LEVELS BEGIN TO COOL. THE
NAM AND GFS ARE BOTH TRYING TO INDICATE SOME LIGHT ACCUMULATIONS
BY EVENING ACROSS PARTS OF OUR WEST. HOWEVER...THINK THIS IS
PROBABLY OVERDONE AS THE GROUND TEMPERATURE IS STILL WARM. IN
ADDITION...THE COBB METHOD IS INDICATING MORE OF A RAIN SNOW MIX
WITH NO ACCUMULATION AS SURFACE TEMPERATURES SHOULD AT LEAST
REMAIN ABOVE FREEZING THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
CYCLONIC LOW LEVEL FLOW AND CAA WILL CONTINUE INTO THIS EVENING
WITH BOTH THE NAM AND GFS INDICATING A WEAK SURFACE TROUGH
PIVOTING DOWN FROM THE NORTH. THIS MAY BE ENOUGH TO PRODUCE A FEW
LIGHT SNOW SHOWERS OR FLURRIES INTO TONIGHT. LOW LEVEL FLOW WILL
BEGIN TO BACK LATER TONIGHT AS HIGH PRESSURE STARTS TO BUILD
IN FROM THE WEST. THIS SHOULD ALLOW FOR ANY PCPN TO TAPER OFF BY
LATE TONIGHT. HIGH PRESSURE WILL THEN BUILD INTO THE REGION
TUESDAY THROUGH WEDNESDAY...LEADING TO DRY CONDITIONS AND MORE
SEASONABLE TEMPERATURES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SPRAWLING HIGH PRESSURE WILL BE RUNNING FROM NEW ENGLAND BACK INTO
THE OHIO VALLEY AT THE BEGINNING OF THE PERIOD. THE HIGH WILL
CONTROL THE REGIONS WEATHER INTO FRIDAY.
MODELS HAVE DIVERGED SOME WITH THEIR SOLUTION FOR THE SYSTEM THAT
KICKS OUT OF THE PLAINS FRIDAY INTO SATURDAY. THE GFS IS MUCH WEAKER
AND QUICKER WITH THE SYSTEM AND THEREFORE PUSHES A CDFNT ACROSS THE
FA SATURDAY...WITH COOLER AND DRIER AIR WORKING IN FOR SUNDAY. THE
ECMWF...DGEX AND TO SOME EXTENT THE CMC ARE SLOWER AND DEEPER. THIS
DELAYS THE START OF THE PCPN BY ABOUT 6 HOURS...BUT ALSO DELAYS
FROPA UNTIL SUNDAY. THE GFS LOOKS LIKE THE OUTLIER...SO LEANED
TOWARDS THE CONSENSUS SOLUTION. SO KEPT HIGHER POPS SATURDAY NIGHT
INTO SUNDAY AND WENT WARMER OVERNIGHT LOWS SATURDAY NIGHT.
WITH HIGH OVER THE REGION INTO FRIDAY...THERE SHOULD BE PLENTY OF
SUNSHINE. COULD SEE SOME PERIODS OF AC OR CI AS WEAK S/W WORKS
THROUGH THE H5 FLOW.
A GRADUAL WARMING WILL OCCUR DURING THE LATER HALF OF THE WEEK. ON
WEDNESDAY...HIGHS ARE EXPECTED TO PUSH INTO THE LOWER TO MID 40S.
HIGHS WILL PUSH INTO THE UPPER 40S TO LOWER 50S BY THE END OF THE
WEEK AND OVER THE WEEKEND.
ANOTHER COOL NIGHT IS EXPECTED WEDNESDAY NIGHT WITH TEMPERATURES
FALLING BACK INTO THE 20S BEFORE THE WARMER AIR BEGINS TO WORK IN
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A COLD FRONT HAS PASSED BY ALL THE TERMINALS THIS MORNING LEAVING
NORTHWEST WINDS AROUND 10 KTS. TRICKY PART OF THE FORECAST TODAY
WILL BE CIGS. CIGS FOR THE MOST PART SHOULD REMAIN IFR THROUGHOUT
THE MORNING. SOME MVFR CIGS MAY TRY TO PUSH INTO THE WESTERN
TERMINALS LATE THIS MORNING AS SOME DRIER AIR MOVES INTO THE LOW
LEVELS. LIGHT RAIN/DRIZZLE IS FORECAST TO CONTINUE ALONG AND SOUTH
OF THE I-71 CORRIDOR THROUGHOUT THE MORNING AND INTO THE EARLY
AFTERNOON. AFTER THAT...THERE MAY BE A BRIEF PERIOD THIS AFTERNOON
WHERE ALL TERMINALS BECOME DRY AND HAVE CIGS RAISE TO MVFR.
HOWEVER...THIS WILL BE SHORT LIVED. WRAPAROUND MOISTURE FROM LOW
PRESSURE TO OUR NORTHEAST WILL BRING CIGS DOWN TO NEAR IFR
CATEGORY THIS EVENING ACROSS MOST TERMINALS. THE ONLY EXCEPTION
FOR THESE LOWER CIGS MAY BE KCVG/KLUK...FARTHER FROM THE LOW.
AS THE WRAPAROUND MOISTURE MOVES INTO THE AREA THIS
EVENING...LIGHT SNOW SHOWERS WILL BECOME POSSIBLE MAINLY ACROSS
THE NORTHERN TERMINALS. THESE SHOWERS AND IFR CIGS WILL CONTINUE
INTO THE EARLY MORNING HOURS TUESDAY. MODELS ARE INDICATING THAT
CIGS MAY FINALLY GO VFR JUST BEFORE SUNRISE TUESDAY MORNING.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS TULSA OK
505 AM CST MON DEC 10 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FOR THE 12Z TAFS... VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES
FOR THE 24 HOUR FORECAST PERIOD. MID CLOUDS WILL COVER THE AREA
MOST OF THE DAY... WITH GUSTY NORTHERLY WINDS AT THE SURFACE.
WINDS WILL EASE DURING THE AFTERNOON AND SKIES ARE EXPECTED TO
CLEAR OUT BY EARLY EVENING.
&&
.PREV DISCUSSION... /ISSUED 334 AM CST MON DEC 10 2012/
DISCUSSION...
NARROW BAND OF SNOW CONTINUES TO PROGRESS QUICKLY EASTWARD ACROSS
SOUTHERN OK / NW TX AHEAD OF THE UPPER TROUGH AXIS. SHORT TERM
DATA HAVE ALIGNED STRONG LIFT WITHIN A SATURATED DENDRITIC GROWTH ZONE
NEAR THE RED RIVER...AND RECENT OBS AND REPORTS NEAR KSPS SUPPORT
THIS BRIEF BUT INTENSE SNOWFALL AREA. LATEST RUC DATA SHIFT THE
FRONTOGENETIC FORCING MOST ALIGNED WITHIN THIS ZONE NORTHEASTWARD
WHILE WEAKENING IT OVER THE NEXT 4-6 HOURS. THUS FORECAST WILL
INCLUDE A HIGHER MEASURABLE SNOW POTENTIAL FOR PORTIONS OF FAR SE
OK BUT ANY ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT. ANY PRECIP
WILL QUICKLY SHIFT EAST OF THE FORECAST AREA BY LATE MORNING.
TEMPS WILL STRUGGLE TO WARM TODAY HOWEVER THE SUN WILL MAKE AN
APPEARANCE WHICH HAS BEEN A RARE SIGHT RECENTLY. VERY COLD TEMPS
TONIGHT WITH LOW DEWPOINTS AND LIGHT WINDS. WHILE NOT CURRENTLY
FORECAST...A FEW LOWS AROUND 10 DEGREES ARE CERTAINLY POSSIBLE.
TEMPS MODERATE BEGINNING TUESDAY AND RETURN ABOVE NORMAL BY
THURSDAY. THE NEXT WAVE TRACKING ACROSS THE SOUTHERN TIER STATES
ARRIVES FRIDAY INTO SATURDAY. WHILE THE TIMING IS IN GENERAL
AGREEMENT AMONGST DATA...THERE ARE TWO MAIN CAMPS REGARDING THE
STRENGTH OF THE WAVE. THE UKMET/ECMWF ARE STRONGER OFFERING A
STOUT CLOSED MID LEVEL LOW...WHILE THE GFS/CANADIAN ARE MORE OPEN
WITH THE WAVE. THE FORECAST WILL MAINTAIN POPS IN THE CHANCE
CATEGORY GIVEN RECENT STRUGGLES TO PRODUCE WIDESPREAD MEANINGFUL
PRECIP...HOWEVER SHOULD THE STRONGER SOLUTION BECOME MORE APPARENT
THEN CHANCES WILL OBVIOUSLY INCREASE.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...06
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
954 AM CST MON DEC 10 2012
.DISCUSSION...FRESHENED UP FORECAST PACKAGE FOLLOWING FROPA. FRONT
HAS CLEARED ALL BUT THE SOUTHEASTERNMOST MARINE ZONES. STRONG COLD
AIR ADVECTION ONGOING ACROSS THE REGION WITH TEMPS AND DEWPOINTS
DROPPING. WINDS ARE ESSENTIALLY REMAINING IN LINE WITH WIND GUSTS
OF 30 TO 35 MPH CONTINUING IN THE VALLEY...AND SLOWLY DECREASING
AS YOU MOVE NORTH. EXPECT VERY WINDY CONDITIONS TO CONTINUE RIGHT
ALONG THE COAST AND WILL CONTINUE THE WIND ADVISORY THERE. STRONG
WINDS CONTINUE TO BE REPORTED OVER THE LAGUNA AND COASTAL
WATERS...AND 12Z RAOB ANALYSIS 850MB AND LOW LEVEL COLD AIR
ADVECTION UNDERWAY EXPECT THAT WILL CONTINUE FOR AT LEAST THE NEXT
4 TO 5 HOURS BEFORE DROPPING CLOSER TO THE 20 TO 25 KNOT RANGE
LATE THIS AFTERNOON/EARLY THIS EVENING. TEMPERATURES TONIGHT LOOK
ON TRACK IN THE MID 40S SOUTH...UPPER 30S NORTH BUT THAT WILL BE A
PRIMARY FOCUS OF THE UPCOMING FORECAST PACKAGE. THE AMOUNT OF DRY
AIR WORKING IN...WITH THE MID TEENS DEWPOINTS IN WEST CENTRAL TEXAS
MAY LEAD TO A DOWNWARD ADJUSTMENT IN TONIGHTS LOWS ONCE A CLEARER
PICTURE ON CLOUD COVER DEVELOPS. FOR NOW LOW TO MID CLOUD DECK
CONTINUES JUST BEHIND THE FRONT. WITH LIGHT FRONTAL OVERRUNNING
OCCURRING FROM ABOUT 4 TO 14KFT. WITH THAT ALSO CONTINUED A SLIGHT
CHANCE FOR STRATIFORM RAIN AT TIMES...BUT WITH NO REAL REINFORCING
WAVE TO INCREASE MID AND LOWER LEVEL OMEGA DO NOT EXPECT LARGE
AREAS OR HEAVY PRECIP TO FORM THROUGH THE REST OF THE DAY AND THE
AFTERNOON...WITH MOST OF OUR MEASURABLE PRECIP PROBABLY OVER FOR
THE DAY. UPDATED PACKAGE/ZONES ALREADY OUT. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 626 AM CST MON DEC 10 2012/
DISCUSSION...AFTER GETTING A LOOK AT CONDITIONS UPSTREAM AND THE
LATEST RAP DATA MADE SLIGHT UPTICKS TO THE WIND FORECAST WHICH
NECESSITATED UPGRADING THE LAGUNA MADRE TO GALE WARNING THROUGH MID
AFTERNOON FOR FREQUENT GALE FORCE GUSTS AND HOISTING A WIND
ADVISORY FOR COASTAL AREAS THROUGH MID AFTERNOON. NO OTHER CHANGES
AT THIS TIME. /68-JGG/
PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 10 2012/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...THE LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE VFR/MVFR CONDITIONS OVER DEEP SOUTH TEXAS. CURRENTLY THE
COLD FRONT IS LOCATED FROM SOUTH OF KBKS AND KHBV TO KAPY AND WILL
MOVE ACROSS THE RIO GRANDE VALLEY AROUND 14Z. THE LIGHT WINDS HAVE
ALLOWED SOME MVFR CIGS/VIS TO DEVELOP AHEAD OF FRONT...THIS WILL
BE SHORT LIVED. SHOWERS AND ISOLATED THUNDERSTORMS ARE ALSO A
POSSIBILITY WITH BETTER CHANCES FROM KMFE EASTWARD. NORTH WINDS
WILL DEVELOP BEHIND THE FRONT AND QUICKLY INCREASING TO 20 TO 25
KT WITH GUSTS TO AROUND 30 BY MID MORNING THROUGH THE AFTERNOON.
CIGS WILL SLOWLY RAISE THROUGH THE DAY BUT SHOULD REMAIN MVFR
THROUGH MID TO LATE AFTERNOON.
PREV DISCUSSION... /ISSUED 425 AM CST MON DEC 10 2012/
SHORT TERM /TODAY THROUGH TUESDAY/...THE COLD FRONT CURRENTLY
LOCATED FROM CORPUS CHRISTI TO ALICE TO LAREDO WILL SWEEP THROUGH
DEEP SOUTH TEXAS THIS MORNING. THE LATEST SURFACE OBSERVATIONS AND
MODEL GUIDANCE INDICATES THAT THE FRONT WILL MOVE THROUGH THE AREA A
LITTLE FASTER. MADE MINOR ADJUSTMENTS TO THE TIMING OF THE FRONT...
WHICH WILL MOVE ACROSS THE NORTHERN COUNTIES IN THE NEXT TWO HOURS
AND THROUGH THE LOWER VALLEY BY MID MORNING. CURRENT BROWNSVILLE
WSR-88D SHOWS LITTLE CONVECTION ACROSS DEEP SOUTH TEXAS BUT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS ARE STILL EXPECTED THIS
MORNING. MUCH COOLER TODAY WITH HIGH TEMPERATURES ALMOST 30 DEGREES
COOLER THAN YESTERDAY. HIGH TEMPERATURES TODAY WILL OCCUR THIS
MORNING THEN TEMPERATURES WILL HOLD STEADY FOR A FEW HOURS BEFORE
DECREASING THIS AFTERNOON. BREEZY NORTH WINDS WILL OCCUR IN THE WAKE
OF THE FRONT AND CONTINUE THROUGH THE DAY. OVERNIGHT LOW
TEMPERATURES FOR TONIGHT WILL FALL INTO THE UPPER 30S OVER THE
NORTHERN AREAS AND IN THE LOWER 40S IN THE VALLEY AND ALONG THE
COAST. HIGH TEMPERATURES FOR TUESDAY WILL BE IN THE 60S.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...BENIGN CONDITIONS WILL
CONTINUE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS SURFACE HIGH
PRESSURE COMBINES WITH A VERY DRY ATMOSPHERE IN THE WAKE OF THE COLD
FRONT MENTIONED ABOVE. ISOLATED SHOWERS WILL DEVELOP THURSDAY...AND
CONTINUE THROUGH FRIDAY...AS A DEVELOPING ONSHORE FLOW PUMPS DEEPER
MOISTURE INTO DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY...AND
INTERACTS WITH A SERIES OF WEAK MID-LEVEL DISTURBANCES PASSING
OVERHEAD IN THE WEST-SOUTHWEST TO EAST-NORTHEAST 500 MB FLOW. A
BRIEF RESPITE IN THE PRECIPITATION MAY OCCUR FRIDAY NIGHT BEFORE
BEGINNING AGAIN SATURDAY...AND LASTING THROUGH SUNDAY...DUE TO THE
SLOW PASSAGE OF A WEAK COLD FRONT. BELOW NORMAL TEMPERATURES EARLY
IN THE LONG TERM PERIOD WILL QUICKLY RETURN TO ABOVE NORMAL LEVELS
DUE TO THE RE-DEVELOPING ONSHORE FLOW.
MARINE...TODAY THROUGH TUESDAY...THE COLD FRONT WILL MOVE THROUGH
THE LOWER TEXAS COASTAL WATERS LATER THIS MORNING RESULTING IN
VERY STRONG NORTH WINDS CONTINUING THROUGH THIS AFTERNOON. A GALE
WARNING IS IN EFFECT THROUGH THIS AFTERNOON FOR THE GULF WATERS
EAST OF PADRE ISLAND. SMALL ADVISORY CONDITIONS ARE LIKELY ON THE
LAGUNA MADRE THROUGH THIS AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE LOWER TEXAS COASTAL
WATERS TODAY. SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE THIS
EVENING THROUGH EARLY TUESDAY MORNING ON THE GULF WATERS. HIGH
PRESSURE SETTLES OVER THE AREA IN THE WAKE OF THE FRONT.
TUESDAY NIGHT THROUGH SUNDAY...GENERALLY MODERATE WINDS AND SEAS
ARE LARGELY EXPECTED THROUGH THE PERIOD...AS AN ONSHORE FLOW RE-
DEVELOPS AND THEN PREVAILS. SMALL CRAFT MAY NEED TO EXERCISE
CAUTION FOR THE GULF OF MEXICO WATERS EAST OF PADRE ISLAND FROM
TUESDAY NIGHT THROUGH SATURDAY. THE APPROACH AND PASSAGE OF A WEAK
COLD FRONT SATURDAY NIGHT WILL BRING A SLIGHT DECREASE IN WINDS
AND SEAS FOR THAT TIME AND THROUGH SUNDAY.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ251-256-257.
GM...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM THIS AFTERNOON TO 6 PM
CST THIS EVENING FOR GMZ130-132-135.
GALE WARNING UNTIL 2 PM CST THIS AFTERNOON FOR GMZ130-132-135.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 4 AM CST TUESDAY
FOR GMZ150-155-170-175.
GALE WARNING UNTIL 6 PM CST THIS EVENING FOR GMZ150-155-170-175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/54
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
626 AM CST MON DEC 10 2012
.DISCUSSION...AFTER GETTING A LOOK AT CONDITIONS UPSTREAM AND THE
LATEST RAP DATA MADE SLIGHT UPTICKS TO THE WIND FORECAST WHICH
NECESSITATED UPGRADING THE LAGUNA MADRE TO GALE WARNING THROUGH MID
AFTERNOON FOR FREQUENT GALE FORCE GUSTS AND HOISTING A WIND
ADVISORY FOR COASTAL AREAS THROUGH MID AFTERNOON. NO OTHER CHANGES
AT THIS TIME. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 10 2012/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...THE LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE VFR/MVFR CONDITIONS OVER DEEP SOUTH TEXAS. CURRENTLY THE
COLD FRONT IS LOCATED FROM SOUTH OF KBKS AND KHBV TO KAPY AND WILL
MOVE ACROSS THE RIO GRANDE VALLEY AROUND 14Z. THE LIGHT WINDS HAVE
ALLOWED SOME MVFR CIGS/VIS TO DEVELOP AHEAD OF FRONT...THIS WILL
BE SHORT LIVED. SHOWERS AND ISOLATED THUNDERSTORMS ARE ALSO A
POSSIBILITY WITH BETTER CHANCES FROM KMFE EASTWARD. NORTH WINDS
WILL DEVELOP BEHIND THE FRONT AND QUICKLY INCREASING TO 20 TO 25
KT WITH GUSTS TO AROUND 30 BY MID MORNING THROUGH THE AFTERNOON.
CIGS WILL SLOWLY RAISE THROUGH THE DAY BUT SHOULD REMAIN MVFR
THROUGH MID TO LATE AFTERNOON.
PREV DISCUSSION... /ISSUED 425 AM CST MON DEC 10 2012/
SHORT TERM /TODAY THROUGH TUESDAY/...THE COLD FRONT CURRENTLY
LOCATED FROM CORPUS CHRISTI TO ALICE TO LAREDO WILL SWEEP THROUGH
DEEP SOUTH TEXAS THIS MORNING. THE LATEST SURFACE OBSERVATIONS AND
MODEL GUIDANCE INDICATES THAT THE FRONT WILL MOVE THROUGH THE AREA A
LITTLE FASTER. MADE MINOR ADJUSTMENTS TO THE TIMING OF THE FRONT...
WHICH WILL MOVE ACROSS THE NORTHERN COUNTIES IN THE NEXT TWO HOURS
AND THROUGH THE LOWER VALLEY BY MID MORNING. CURRENT BROWNSVILLE
WSR-88D SHOWS LITTLE CONVECTION ACROSS DEEP SOUTH TEXAS BUT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS ARE STILL EXPECTED THIS
MORNING. MUCH COOLER TODAY WITH HIGH TEMPERATURES ALMOST 30 DEGREES
COOLER THAN YESTERDAY. HIGH TEMPERATURES TODAY WILL OCCUR THIS
MORNING THEN TEMPERATURES WILL HOLD STEADY FOR A FEW HOURS BEFORE
DECREASING THIS AFTERNOON. BREEZY NORTH WINDS WILL OCCUR IN THE WAKE
OF THE FRONT AND CONTINUE THROUGH THE DAY. OVERNIGHT LOW
TEMPERATURES FOR TONIGHT WILL FALL INTO THE UPPER 30S OVER THE
NORTHERN AREAS AND IN THE LOWER 40S IN THE VALLEY AND ALONG THE
COAST. HIGH TEMPERATURES FOR TUESDAY WILL BE IN THE 60S.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...BENIGN CONDITIONS WILL
CONTINUE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS SURFACE HIGH
PRESSURE COMBINES WITH A VERY DRY ATMOSPHERE IN THE WAKE OF THE COLD
FRONT MENTIONED ABOVE. ISOLATED SHOWERS WILL DEVELOP THURSDAY...AND
CONTINUE THROUGH FRIDAY...AS A DEVELOPING ONSHORE FLOW PUMPS DEEPER
MOISTURE INTO DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY...AND
INTERACTS WITH A SERIES OF WEAK MID-LEVEL DISTURBANCES PASSING
OVERHEAD IN THE WEST-SOUTHWEST TO EAST-NORTHEAST 500 MB FLOW. A
BRIEF RESPITE IN THE PRECIPITATION MAY OCCUR FRIDAY NIGHT BEFORE
BEGINNING AGAIN SATURDAY...AND LASTING THROUGH SUNDAY...DUE TO THE
SLOW PASSAGE OF A WEAK COLD FRONT. BELOW NORMAL TEMPERATURES EARLY
IN THE LONG TERM PERIOD WILL QUICKLY RETURN TO ABOVE NORMAL LEVELS
DUE TO THE RE-DEVELOPING ONSHORE FLOW.
MARINE...TODAY THROUGH TUESDAY...THE COLD FRONT WILL MOVE THROUGH
THE LOWER TEXAS COASTAL WATERS LATER THIS MORNING RESULTING IN
VERY STRONG NORTH WINDS CONTINUING THROUGH THIS AFTERNOON. A GALE
WARNING IS IN EFFECT THROUGH THIS AFTERNOON FOR THE GULF WATERS
EAST OF PADRE ISLAND. SMALL ADVISORY CONDITIONS ARE LIKELY ON THE
LAGUNA MADRE THROUGH THIS AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE LOWER TEXAS COASTAL
WATERS TODAY. SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE THIS
EVENING THROUGH EARLY TUESDAY MORNING ON THE GULF WATERS. HIGH
PRESSURE SETTLES OVER THE AREA IN THE WAKE OF THE FRONT.
TUESDAY NIGHT THROUGH SUNDAY...GENERALLY MODERATE WINDS AND SEAS
ARE LARGELY EXPECTED THROUGH THE PERIOD...AS AN ONSHORE FLOW RE-
DEVELOPS AND THEN PREVAILS. SMALL CRAFT MAY NEED TO EXERCISE
CAUTION FOR THE GULF OF MEXICO WATERS EAST OF PADRE ISLAND FROM
TUESDAY NIGHT THROUGH SATURDAY. THE APPROACH AND PASSAGE OF A WEAK
COLD FRONT SATURDAY NIGHT WILL BRING A SLIGHT DECREASE IN WINDS
AND SEAS FOR THAT TIME AND THROUGH SUNDAY.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ251-256-257.
GM...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM THIS AFTERNOON TO 6 PM
CST THIS EVENING FOR GMZ130-132-135.
GALE WARNING UNTIL 2 PM CST THIS AFTERNOON FOR GMZ130-132-135.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 4 AM CST TUESDAY
FOR GMZ150-155-170-175.
GALE WARNING UNTIL 6 PM CST THIS EVENING FOR GMZ150-155-170-175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/54
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
320 PM MST MON DEC 10 2012
.SHORT TERM...STILL DEALING WITH A MODERATE NORTHWEST FLOW PATTERN
ACROSS COLORADO AND STILL PLENTY OF MOISTURE UPSTREAM TO KEEP
LIGHT SNOW GOING IN THE MOUNTAINS. DEEPEST MOISTURE WILL BE UNTIL
MIDNIGHT AND THEN GRADUALLY MOISTURE DEPTH GETS MORE SHALLOW
DURING THE DAY ON TUESDAY. WILL KEEP LIKELY POPS IN THE MOUNTAINS
THROUGH EARLY TUESDAY THEN DIMINISHING LATE IN THE PERIOD. CROSS
SECTIONS INDICATE ANOTHER 2-4 INCHES IN THE MOUNTAINS TONIGHT AND
THEN ANOTHER INCH TUESDAY MORNING. AS FOR THE NORTHEAST
PLAINS...THE GUSTY NORTHWEST WINDS WILL DECREASE THIS EVENING AS
WINDS DECOUPLE FROM THE STRONGER FLOW ALOFT AND WEAK SURGE SHIFTS
WINDS A BIT MORE NORTHERLY. RUC AND GFS HINTS AT SOME LOW QPF
OVER PORTIONS OF THE PLAINS...ESPECIALLY OVER THE PALMER DIVIDE.
GIVEN THE NORTHERLY FLOW WILL KEEP A VERY LOW POP IN THOSE
LOCATIONS BUT NOT OVER THE FRONT RANGE. SKIES WILL CLEAR LATER
TONIGHT BEHIND THIS WEAK WAVE.
.LONG TERM...UPPER TROF AXIS MOVES INTO CENTAL PLAINS TUESDAY
EVENING WITH MODERATE TO STRONG NORTHWEST FLOW ALOFT ACROSS
COLORADO. SUBSIDENCE MID LEVEL SUBSIDENCE TO SPREAD ACROSS AREA
WITH DECREASING MID LEVEL MOISTURE. WITH INCREASING WARM AIR
ADVECTION AND STABILITY...SHOULD SEE MOUNTAIN SNOW SHOWERS END
DURING THE EVENING. MODELS SHOW WEAK MOUNTAIN WAVE DEVELOPING
OVERNIGHT TUESDAY WITH CROSS MOUNTAIN FLOW INCREASING TO AROUND 50
KTS AT MOUNTAIN TOP INTO EARLY WEDNESDAY MORNING. SHOULD CONTINUE
TO BE GUSTY ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS...THOUGH THE
STRONGEST WINDS APPEAR TO REMAIN ACROSS THE HIGHER RIDGES. SPEEDS
SHOULD REMAIN BELOW HIGH WIND CRITERIA. RIDGE AXIS TO MOVE ACROSS
THE STATE WEDNESDAY INTO THURSDAY WITH WESTERLY FLOW ALOFT
BECOMING MORE SOUTHWEST AS UPPER TROUGH MOVES INTO THE GREAT
BASIN. DRY CONDITIONS TO PREVAIL WEDNESDAY AND THURSDAY WITH
TEMPERATURES EXPECTED TO WARM BACK TO SEASONAL NORMALS. FOR
FRIDAY...BOTH DGEX AND ECMWF SHOW UPPER TROUGH MOVING ACROSS
COLORADO WHILE GFS BRINGS TROUGH ACROSS THE STATE FRIDAY EVENING.
AT THIS TIME NOT SURE WHICH SOLUTIONS WILL BE CORRECT...BUT THERE
IS A GENERAL CONSENSUS OF MOISTURE INCREASING ACROSS COLORADO
ALONG WITH SOME MID LEVEL ASCENT. SHOULD BE ENOUGH FOR A CHANCE OF
MOUNTAIN SNOW. DGEX AND ECMWF ALSO GENERATE SOME LIGHT PRECIP
ACROSS SOUTHERN AND FAR EASTERN COLORADO LATE AFTERNOON AND
EVENING. WILL INCLUDE SOME LOW POPS FAR EASTERN ZONES TO ACCOUNT
FOR THIS WITH DRY CONDITIONS ELSEWHERE.
ON SATURDAY...FLOW ALOFT TO BECOME NORTHWEST AS UPPER TROUGH MOVES
ACROSS CENTRAL PLAINS. MODELS SHOW MAINLY DRY AIRMASS OVER
COLORADO...BUT STILL DECENT MOISTURE AND OROGRAPHICS ACROSS
MOUNTAINS TO KEEP SOME SNOW GOING. OTHERWISE DRY CONDITIONS TO
PREVAIL. FOR SUNDAY AND MONDAY...NORTHWEST FLOW ALOFT TO CONTINUE
ENOUGH OROGRAPHIC SUNDAY FOR A SLIGHT CHANCE OF MOUNTAIN SNOW. .
LATEST ECMWF HI RES MODEL HINTS AT A WEAK DISTURBANCE EMBEDDED IN
THE FLOW MOVING ACROSS THE STATE SUNDAY NIGHT AND MONDAY WHICH
MAY HELP INCREASE SNOW CHANCES ACROSS MOUNTAINS AND BRING A
PERHAPS A SLIGHT CHANCE OF SNOW THE THE PLAINS. LATEST DGEX AND
GFS KEEP THINGS DRY MONDAY. FOR NOW WILL LEAN TOWARD THE DRIER
SOLUTIONS OF THE DGEX AND GFS WITH A SLOW WARMING TREND.
&&
.AVIATION...NORTHWEST SURFACE WINDS AT 15-25KT HAVE SURFACED AT
BJC AND APA AND STILL TRYING TO DEVELOP AT KDEN. WILL KEEP THE
IDEA OF SOME BETTER MIXING WITH GUSTY WINDS TO MATERIALIZE AT DEN
FOR A SHORT TIME THROUGH 00Z. FOR TONIGHT A NON DESCRIPT SURFACE
PATTERN WITH A DISORGANIZED FRONT WHICH MAY KEEP SOME WEAK
NORTHERLY FLOW IN THE TERMINALS THROUGH MIDNIGHT BEFORE SLOWLY
RETURNING TO DRAINAGE WINDS LATER IN THE NIGHT. WITH THE MOISTURE
UPSTREAM MAY SEE SOME CEILINGS DIPPING INTO THE 6000-7000 FOOT AGL
RANGE AND MAYBE A BIT LOWER AT APA. WILL STILL KEEP TERMINALS DRY
EXCEPT A VCSH AT APA.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....D-L
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1049 AM MST MON DEC 10 2012
.UPDATE...
&&
.AVIATION...STILL A BIT UNCLEAR HOW THE WINDS WILL BEHAVE THIS
AFTERNOON. WEAK SURGE MOVING THRU NORTHEAST CO WITH A MID LVL
CLOUD DECK WHICH SHOULD SCATTER OUT AROUND 19Z. LOOKS LIKE A WEAK
LONGMONT ANTICYLONE TRYING TO DEVELOP WITH STRONG NW WINDS NEAR
THE WYOMING BORDER AND A WEAK NORTHEAST REFLECTION OF WINDS AT
THIS TIME NORTH OF DENVER. HOWEVER STILL THINK BIT BETTER MIXING
WILL DEVELOP MID AFTERNOON WITH SOME SUN MAKING IT THROUGH WHICH
WILL MIX DOWN SOME OF THE STRONGER NW WINDS. THE NEXT WEAK
IMPULSE ACROSS MONTANA WILL MOVE SOUTHWARD THIS EVENING OVER THE
FRONT RANGE WITH ANOTHER DECK OF CLOUDS. THE RUC INDICATING SOME
LIGHT QPF POSSIBLE OVER THE PALMER DIVIDE. LEFT PRECIP OUT OF
DEN/BJC WITH TOO MUCH DOWNSLOPE BUT APA MAY GET A SHOWERS. WILL
INDICATE A VCSH FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 901 AM MST MON DEC 10 2012/
UPDATE...
SHORT TERM...DECENT WINDS IN THE FRONT RANGE THIS AM BUT LOOKING
AT A DECREASING TREND FOR THE REST OF THIS MORNING AS MOUNTAIN TOP
LEVEL INVERSION BEGINS TO WEAKEN. AS LOW LEVELS MIX OUT A BIT
SHOULD SEE STRONGER NORTHWEST WINDS SPREAD OUT OVER THE PLAINS
THIS AFTERNOON. WILL BEEF UP WINDS SOMEWHAT. APPEARS TO BE SOME
ONGOING SNOW IN THE HIGHER MOUNTAINS VIA WEB CAMS THIS MORNING AND
HAVE ALSO INCREASED POPS IN THE MOUNTAINS AS WELL. NOT LOOKING AT
HILITES FOR NOW AS MOISTURE DEPTH NOT ALL THAT DEEP THROUGH
TONIGHT. CERTAINLY SOME LIGHT ACCUMULATIONS ARE LIKELY. VIA
SATELLITE...LOOKS LIKE TWO DISTINCT WAVES IN THE FLOW...WITH ONE
COMING THRU THE NORTHERN MOUNTAINS THIS MORNING AND ANOTHER ONE
BACK UP OVER WESTERN MONTANA. SO MAY SEE A DECREASE IN THE
SNOWFALL THIS AFTERNOON BEFORE INCREASING A BIT THIS EVENING.
AVIATION...MAIN CHANGE TO UPCOMING TAFS IS TO BEEF UP THE
NORTHWEST WINDS/GUSTS THIS AFTERNOON WITH GUSTS IN THE 20-30KT
RANGE. KDEN WILL BE MOST SUSCEPTIBLE TO THIS AS LOW LEVELS MIX
OUT AND SURFACE GRADIENT REMAINS IN THE 7-9MB RANGE ACROSS THE
STATE THIS AFTERNOON. WILL SEE SOME LOWERING CEILINGS THIS
AFTERNOON WITH INCOMING MOISTURE FROM WYOMING AND MONTANA. MAY GET
START TO GET LOW ENOUGH FOR ILS APPROACH AT DENVER IN THE
6000-7000 FOOT RANGE.
PREV DISCUSSION... /ISSUED 504 AM MST MON DEC 10 2012/
SHORT TERM...UPPER JET SHIFTING EAST WITH MOIST MID LEVEL WARM
ADVECTION THIS MORNING...THEN ANOTHER WEAKER TROUGH MOVES NORTH OF
US AND BRINGS A LITTLE DESTABILIZATION. MID LEVEL NW WINDS WEAKEN
AND BECOME A BIT MORE WESTERLY TODAY...THEN INCREASE AGAIN
TONIGHT. IT WILL BE INTERESTING TO SEE HOW MUCH MIXING THERE IS
TODAY WITH THE WARM ADVECTION OFF THE GROUND AND THE CLOUD COVER.
CURRENT TEMPERATURE FORECAST IS IN THE MIDDLE OF GUIDANCE AND
SEEMS REASONABLE...WITH WARMER READINGS NEAR THE FOOTHILLS WHERE
THERE WILL BE MORE SUN AND WIND...AND HIGHER TERRAIN TO BEGIN
WITH. MORE CLOUD COVER AND LIGHTER WINDS COULD HOLD TEMPERATURES
DOWN AROUND FREEZING ON THE PLAINS. CLOUD COVER MAY THIN
TONIGHT...BUT THERE SHOULD STILL BE SOME AND WEST WINDS SHOULD
ALSO CONTINUE AND KEEP TEMPERATURES UP. WE ARE WARMER THAN
GUIDANCE TONIGHT BUT THAT LOOKS GOOD.
AS FOR MOUNTAIN WINDS...MAYBE A LITTLE WAVE AMPLIFICATION UP
HIGH...BUT STRONG WINDS APPEAR LIMITED TO ABOUT 10 THOUSAND FEET
SO FAR. SOME DOWNWARD PENETRATION IN THE USUAL SPOTS MAINLY WEST
OF BOULDER...BUT ONLY ABOUT 40 MPH GUSTS IN THESE AREAS. STABILITY
STRUCTURE TO SUPPORT AMPLIFICATION SHOULD BE GOING AWAY SOON...SO
THREAT OF STRONG WINDS DOWN INTO THE FOOTHILLS WILL TRANSITION TO
MIXING THIS MORNING...WITH SOME DECREASE IN FLOW PROBABLY
DOMINATING OVER ANY INCREASE IN MIXING THIS AFTERNOON. WINDS COULD
COME UP AGAIN LATE TONIGHT AS ANOTHER JET STREAK MOVES OVER...THIS
ALSO DOES NOT APPEAR TO BE MUCH OF A HIGH WIND THREAT.
MOUNTAIN SNOW WILL LARGELY BE LIMITED BY STABILITY...BUT THERE IS
A PERIOD LATE THIS AFTERNOON AND THIS EVENING WHEN THERE COULD BE
STRONGER VERTICAL MOTIONS. I ADDED A LITTLE MORE SNOW IN THIS TIME
FRAME...BUT IT DOES NOT APPEAR TO NEED AN ADVISORY.
LONG TERM...OVERALL NO SIGNIFICANT ADJUSTMENTS TO THE ONGOING
FORECAST. ON TUESDAY...A STRONG NORTHWESTERLY FLOW ALOFT WILL
REMAIN IN PLACE OVER THE CWFA. A BROAD RIDGE OF HIGH PRESSURE WILL
BE OVER WESTERN COLORADO WITH NOSE OF A 120KT UPPER JET AHEAD OF
IT. THIS FEATURE IS PROGGED TO ADVECT ACROSS NORTHERN COLORADO
THROUGH THE DAY TUESDAY. ONCE THE JETSTREAM SHIFTS TO THE EAST
LATE IN THE DAY TUESDAY...A WEAK MOUNTAIN WAVE DEVELOPS AS
SUBSIDENCE INCREASES AT 700 MB AND THE SHEAR ASSOCIATED WITH THE
PASSAGE OF THE UPPER JET WEAKENS. THE CROSS-MTN COMPONENT LATE
TUESDAY/TUESDAY NIGHT WILL BE AROUND 40 KTS. ALTHOUGH GUSTY WINDS
WILL CONTINUE ESPECIALLY IN THE MOUNTAINS AND HIGHER FOOTHILLS...
NOTHING STRONG ENOUGH IN THE MDL CROSS-SECTIONS TO WARRANT A
HIGHLIGHT YET. AS FOR THE SNOW...INCREASE WARM AIR ADVECTION/STABILITY
WILL ALLOW FOR A DECREASE CHANCE OF SNOW TUESDAY INTO TUESDAY
EVENING. WEDNESDAY AND THURSDAY...THE RIDGE AXIS PASSES ACROSS THE
STATE AND THE FLOW ALOFT GOES FM WLY ON WEDNESDAY TO SOUTHWESTERLY
ON THURSDAY. IT WILL BE DRY BOTH DAYS WITH TEMPERATURES PROGGED TO
CLIMB BACK TO NEAR SEASONAL NORMALS. FOR FRIDAY THROUGH SUNDAY...
MOISTURE WILL INCREASE OVER COLORADO AS THE NEXT STORM SYSTEM
APPROACHES FM THE SOUTHWEST. THIS SYSTEM COULD PASS ACROSS SRN
COLORADO LATE FRIDAY...WITH MORE RIDGING ON SATURDAY...THEN
ANOTHER WEAK TROUGH IS PROGGED TO PASS ACROSS THE STATE ON SUNDAY.
TEMPERATURES WILL COOL OFF BY THAT TIME WITH A CHANCE OF SNOW
RETURNING TO THE MOUNTAINS...AND POSSIBLY EVEN THE NORTHEAST
PLAINS. TOO FAR INTO THE FUTURE TO ADDRESS MORE THAN A CHANCE POPS
IN THE MOUNTAINS AT THIS POINT.
AVIATION...VFR CONDITIONS THROUGH TONIGHT. KDEN/KAPA WILL HAVE
WEST TO NORTHWEST WINDS MIXING DOWN BY MIDDAY...BUT SPEEDS SHOULD
BE LESS THAN 20 KNOTS. KBJC MAY HAVE STRONGER GUSTS THIS MORNING.
CLOUDS WILL LOWER WITH INCREASING MOISTURE THIS AFTERNOON AND
THERE IS A SLIGHT CHANCE OF CEILINGS LOW ENOUGH TO REQUIRE
INSTRUMENT APPROACHES TO KDEN AT TIMES...BUT MORE LIKELY CEILINGS
WILL BE OVER 7000 FT AGL.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION...UPDATED
NWS MELBOURNE FL
243 PM EST MON DEC 10 2012
.DISCUSSION...
...CHANCE FOR STRONG STORMS AND HEAVY RAINFALL NEXT FEW DAYS...
CURRENTLY/REST OF THE AFTERNOON...A PERIOD OF HEATING HAS OCCURRED
ACROSS SOUTHERN SECTIONS THIS AFTERNOON. SOME LOW LEVEL SHEAR EXISTS...
SO WILL HAVE TO WATCH FOR A FEW STRONG STORMS THROUGH ABOUT
SUNSET.
TONIGHT-TUE...VORT MAX WITH ASSOCIATED CONVECTION IN THE EASTERN
GULF WILL SWEEP ACROSS THE PENINSULA THIS EVENING AND WELL
NORTHEAST OF THE AREA BY TUE MORNING. VERY HIGH MOISTURE VALUES...
NEAR 2 INCHES PRECIPITABLE WATER...WILL BE IN PLACE AS THIS
FEATURE MOVES ACROSS. THIS WILL BRING RATHER HIGH RAIN CHANCES FOR
MOST OF THE AREA THROUGH THE REMAINDER OF THE DAY. MOS POPS ARE
60-80 PERCENT AREAWIDE BUT HAVE SETTLED IN AT 60-70 PERCENT
TONIGHT.
SOME LOCAL HEAVY RAIN IS EXPECTED ALONG WITH ISOLATED STORMS...
ESPECIALLY NEAR THE VORT MAX AS IT MOVES ACROSS THE PENINSULA
THIS EVENING.
THE OTHER WEATHER ELEMENT TO WATCH OUT FOR IS LATE NIGHT LOW
STRATUS...WHICH COULD EVOLVE INTO A FRONTAL FOG EVENT. MOS HAS
VERY LOW CEILINGS/VISIBILITIES...SO WILL STAY WITH PREVIOUS
FORECAST WHICH KEEPS A MENTION OF PATCHY FOG OVERNIGHT. MAY NEED
TO HIT THE FOG HARDER IN SUBSEQUENT UPDATES.
THE GFS SHOWS SOME SUPPRESSING EFFECT BEHIND THE VORT MAX AND
LOWERS POPS ON TUE TO 30-40 PERCENT. THAT IS A BIT TOO MUCH OF A
RUN TO RUN CHANGE...ESPECIALLY SINCE A WEAK FRONTAL BOUNDARY WILL
BE APPROACHING THE AREA. WILL GO WITH 50 PERCENT POPS ACROSS THE
BOARD FOR NOW. INCREASING DEEP LAYER SHEAR MAY HELP TO LEND SOME
ORGANIZATION TO CONVECTION...BUT THE AMOUNT OF DESTABILIZATION IS
QUESTIONABLE DUE TO LINGERING LOW CLOUDS IN THE MORNING AND
CONVECTIVE DEBRIS CLOUDS.
00Z WED-12Z THU...
WET WX PATTERN CONTINUES FOR CNTRL FL AS THE LOW/MID LEVEL RIDGE
OVER THE FL STRAITS/NW CARIB INTERACTS WITH THE SLOW MOVING FRONTAL
TROF PUSHING THRU THE DEEP S. THE RESULTING DEEP S/SW FLOW ACRS THE
REGION WILL CONTINUE TO PULL TROPICAL MOISTURE UP FROM THE CARIB.
PWAT VALUES EXPECTED TO REACH AS HIGH AS FROM 1.8"-2.0" THRU 00Z TUE
BEFORE DRIER AIR BEGINS TO ADVECT INTO THE PENINSULA.
DEEP SW FLOW REGIMES OFTEN GENERATE MODERATE TO STRONG ISENTROPIC
LIFT...ESP IN THE PRESENCE OF AN APPROACHING COLD FRONT. THIS CASE
WILL BE NO EXCEPTION AS FRONTAL BNDRY SLOWS AND STALLS ACRS THE N FL
PENINSULA ON TUE. SFC BASED INSTABILITY WILL BE PRESENT IN THE FORM
OF M60S/L70S SFC DEWPOINTS AND MAX TEMPS 5-10F ABV AVG...MIN TEMPS
10-15 ABV AVG.
LATEST RAP ANALYSIS SHOWS UPSTREAM MID LVL LAPSE RATES ARE
UNIMPRESSIVE...LARGELY BTWN 5.5-6.0C/KM. HOWEVER...EXPECT TO SEE
THESE STEEPEN AS THE FRONTAL TROF PUSHES ACRS THE GOMEX...
ACCOMPANIED BY AN H85-H70 THERMAL TROF. UPR LVL DIVERGENCE ALSO MAY
INCREASE AS A THE RIGHT REAR QUAD OF A LARGE H25 LIFTING JET...
EXTENDING FROM THE CANADIAN MARITIMES TO THE RIO GRANDE VALLEY...
PUSHES EAST AND COUPLES WITH A 100KT JET CORE CURRENTLY PASSING
SOUTH OF THE BAJA PENINSULA.
COMBINATION OF MID/UPR LVL FORCING AND LOW LVL BUOYANCY SHOULD
SUPPORT SCT/NMRS SHRAS AND ISOLD/SCT TSRAS ACROSS THE REGION.
INCREASED POPS TO 60-70PCT TUE NIGHT THRU WED...40-60 POPS LINGERING
INTO WED NIGHT. BUMPED THU POPS UP ABOUT 10PCT AS WELL AS LATEST
MODEL RUN SHOWS DEEP MOISTURE LINGERING THRU 18Z. MIDDAY THU CUTOFF
TIME LOOKS GOOD.
SPC KEEPS CNTRL FL UNDER A SLIGHT RISK FOR SVR WX BTWN 00Z-12Z
WED...GENERAL THUNDER 12Z WED THRU 12Z THU WITH THE HIGHEST STORM
POTENTIAL DVLPG IN THE VCNTY OF THE FRONTAL BNDRY ITSELF. FLOODING
CONCERNS MINIMAL...HOWEVER...WITH ANNUAL PRECIP DEFICITS RANGING
FROM 2" TO 12".
THU-SAT...(MODIFIED PREV DISC)
ROBUST SHORTWAVE SWINGS THROUGH THE LOWER MS VALLEY THEN THROUGH THE
SE US BY THURSDAY MORNING...DEVELOPING A SFC LOW OFF THE FL EAST
COAST ALONG THE STALLED BOUNDARY AND DRIVING IT THROUGH THE STATE
AROUND MIDDAY THURSDAY. WILL KEEP THE MENTION ISOLD/SCT SHOWERS
ACROSS THE TREASURE COAST AND LOCAL ATLANTIC THROUGH MID DAY ON
THURSDAY.
THE SURFACE HIGH BEHIND THE FRONT WILL QUICKLY STRING OUT ACROSS THE
DEEP SOUTH AND WESTERN ATLANTIC BY THE END OF THE WEEK...BRINGING
THE FLOW AROUND TO THE EAST BY FRIDAY AND MODERATING ANY
POST-FRONTAL COOLDOWN. BOTH MODELS SHOW ENOUGH LINGERING MOISTURE
THAT ONSHORE MOVING COASTAL SHOWERS MAY BE A POSSIBILITY BY FRIDAY
NIGHT INTO SATURDAY.
&&
.AVIATION...
AN AREA OF SHOWERS WITH A FEW STORMS IS EXPECTED TO MOVE ACROSS
THE PENINSULA LATE THIS AFTERNOON AND THROUGH THE EVENING HOURS.
DID NOT HIT THIS REAL HARD IN THE TAFS YET...JUST PUTTING
PREVAILING LIGHT RAIN WITH TEMPORARY MVFR. EXPECT SOME TWEAKING TO
THE TIMING AND LOWERING OF THE CEILINGS AND VISIBILITIES FOR SEVERAL
TERMINALS.
ONCE THE PRECIP MOVES ON BY TO THE NORTHEAST AFTER MIDNIGHT...THERE
WILL BE SOME STRATUS DEVELOPING...WHICH COULD LEAD TO LIFR
CONDITIONS. AGAIN...DID NOT HIT THIS QUITE AS HARD AS THE LATEST
MOS GUIDANCE SHOWS...BUT WITH VERY SOUPY AIR MASS...WE MAY EVOLVE
INTO A FRONTAL FOG TYPE SCENARIO THAT LASTS INTO THE MID-LATE
MORNING ON TUE.
&&
.MARINE...
TONIGHT-TUE...THE GFS SHOWS SOME CONVECTIVE ENHANCEMENT TO THE
WIND FIELDS TONIGHT...SO HAVE CAPPED THEM AT 15-20 KNOTS. WILL
START OFF WITH AN EXERCISE CAUTION STATEMENT FOR ALL BUT THE
NORTHERN NEARSHORE ZONE. EXPECT AT LEAST ISOLATED STORMS TO MOVE
ACROSS THE WATERS...MAINLY IN THE 00Z-06Z TIME PERIOD. A FEW COULD
BE STRONG...ESPECIALLY OVER THE GULF STREAM.
THE MODELS WEAKEN THE PRESSURE GRADIENT A LITTLE ON TUE AS A
WEAK FRONTAL BOUNDARY APPROACHES. MARINERS WILL NEED TO BE ALERT
FOR CONVECTIVE DEVELOPMENT OVER LAND AREAS MOVING OFFSHORE...MAINLY
IN THE AFTERNOON.
THU-FRI (PREVIOUS DISCUSSION)...FRONT MAKES IT THROUGH THE STATE
WEDNESDAY NIGHT INTO THURSDAY...WITH A BRIEF NORTHERLY WIND SURGE
BEHIND THE PASSAGE BRINGING WINDS AROUND 20KTS THROUGH MIDDAY
THURSDAY BEFORE DROPPING TO 15-20KTS AND VEERING NORTHEAST INTO
THURSDAY NIGHT.
THE SURFACE HIGH WILL PUSH ACROSS THE DEEP SOUTH AND OFF THE MID
ATLC COAST THRU THE END OF THE WORK WEEK...BRINGING WINDS AROUND TO
THE EAST FOR FRIDAY THROUGH THE END OF THE WEEK AT AROUND 10-15KTS.
POST FRONTAL WIND SURGE WILL BRING WINDS UP TO 7-8FT OFFSHORE
THROUGH FRIDAY.
SAT...LATEST MODEL FORECASTS SHOW HIGH PRESSURE RIDGE GETTING CLOSER
TO THE AREA...SO WINDS SHOULD DROP OFF TO 10 KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 67 80 64 75 / 70 50 60 70
MCO 66 83 63 79 / 70 50 60 70
MLB 68 82 68 79 / 70 50 70 70
VRB 71 83 67 79 / 60 50 70 70
LEE 65 80 61 75 / 60 50 60 70
SFB 66 81 63 77 / 70 50 60 70
ORL 67 82 63 78 / 70 50 60 70
FPR 70 83 67 79 / 60 50 70 70
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...LASCODY
LONG TERM....BRAGAW
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
415 PM CST MON DEC 10 2012
.DISCUSSION...
302 PM CST
SURFACE TROUGH EXTENDS WEST-EAST FROM ABOUT KRPJ TO KMDW AND OVER
INTO BERRIEN COUNTY MICHIGAN PER 20Z ANALYSIS. SCATTERED SNOW
SHOWERS HAVE BEEN CONFINED TO THE VICINITY OF THE TROUGH AXIS FOR
THE MOST PART THIS AFTERNOON...WITH SOMEWHAT HEAVIER SNOW SHOWERS
OVER LAKE MICHIGAN EXTENDING INTO FAR NORTHEAST PORTER AND LAPORTE
COUNTIES. WHILE A FEW OF THE SNOW SHOWERS OVER NORTHERN IL HAVE
PRODUCED RADAR RETURNS NEAR 35 DBZ AT TIMES...IT APPEARS THE
POTENTIAL FOR PICKING UP ANY MEASURABLE SNOW OF ANY SIGNIFICANCE IS
QUITE LOW. WITH THE BOUNDARY SAFELY SOUTH OF BOTH RFD AND ORD...AND
BOTH LOCATIONS ONLY PICKING UP TRACE AMOUNTS OF SNOW TODAY...IT
LOOKS AS IF THE STREAK OF DAYS WITHOUT MEASURABLE SNOW WILL CONTINUE
PAST 280 DAYS! THUS UNLESS SOMETHING ODD OCCURS...CHICAGO WILL VERY
LIKELY SET A NEW RECORD OF 281 CONSECUTIVE DAYS WITHOUT MEASURABLE
SNOW.
AS COLDER AIR CONTINUES TO SPREAD ACROSS LAKE MICHIGAN THIS
EVENING...LAKE EFFECT SNOW SHOWERS SHOULD BECOME MORE ORGANIZED WITH
NORTH-SOUTH BANDING DEVELOPING OVER MID AND EASTERN LAKE MICHIGAN.
LATEST HIGH-RES GUIDANCE INCLUDING WRF-NMM...WRF-NAM AND RAP RUNS
ALL SUGGEST THAT PORTIONS OF PORTER COUNTY MAY SEE A BRIEF PERIOD OF
LAKE EFFECT INTO THIS EVENING...BEFORE BOUNDARY LAYER WINDS BACK
MORE WESTERLY AFTER MIDNIGHT AND PUSH THE LOW LEVEL CONVERGENT FOCUS
EAST TOWARD THE MICHIGAN SHORE. CURRENT LAKE-ENHANCED BAND OVER FAR
SOUTHERN LAKE MICHIGAN HAS PRODUCED VISIBILITY AS LOW AS 1/2SM-1/4SM
AT SOUTH BEND IN THE LAST HOUR OR SO...AN INDICATION THAT SOME
RELATIVELY HEAVY SNOW MAY FALL FOR AT LEAST A SHORT TIME. 850 HPA
TEMPS COOLING TO AROUND -9C...AND RESULTING LAKE-850 HPA DELTA T
VALUES AROUND 16/17C WOULD POTENTIALLY SUPPORT 1-3/2-4 INCHES IF IT
WERE ABLE TO FOCUS ON A LOCALE FOR A FEW HOURS. GIVEN TRANSIENT
NATURE AND RELATIVELY SHORT DURATION EXPECTED FOR BAND TO REALLY
FOCUS ON NORTHEAST PORTER COUNTY...WOULD THINK THAT THE LOWER END OF
THIS RANGE IS MORE LIKELY THROUGH MIDNIGHT TONIGHT. AGAIN...SNOW
SHOULD END FOR PORTER COUNTY BY 06-09Z TONIGHT AS THE FOCUS DRIFTS
EAST OF THE AREA.
OTHERWISE...CONSIDERABLE AREA OF STRATUS/STRATOCU NOTED PER
AFTERNOON VISIBLE SATELLITE IMAGERY WITHIN LOW LEVEL COLD ADVECTION
BENEATH BROAD UPPER TROUGH WITH SERIES OF WEAK VORTS TRANSITING THE
REGION THROUGH TUESDAY. CLOUDS/FEW FLURRIES THIS AFTERNOON SHOULD
GRADUALLY TRANSITION TO PARTLY CLOUDY CONDITIONS FROM THE WEST LATE
TONIGHT/EARLY TUESDAY...WITH LARGE SCALE UPPER TROUGH AXIS FINALLY
MOVING EAST OF THE AREA TUESDAY NIGHT. BROAD...FLAT UPPER RIDGING
THEN BUILDS ACROSS THE GREAT LAKES AND SOUTHEAST WEDNESDAY/THURSDAY
WITH A PERIOD OF DRY AND SLOWLY MODERATING WEATHER.
NEXT WEATHER MAKER TO MONITOR IS AN UPPER TROUGH CURRENTLY
PROPAGATING ACROSS THE GULF OF ALASKA. MEDIUM RANGE GUIDANCE REMAINS
CONSISTENT IN DIGGING THIS SYSTEM SOUTH ALONG THE WEST COAST THROUGH
MID-WEEK...DEVELOPING INTO A CLOSED LOW ALONG THE CALIFORNIA COAST
BY LATE THURSDAY. THIS SYSTEM IS THEN PROGGED TO MOVE OUT ACROSS THE
PLAINS FRIDAY/FRIDAY NIGHT AND ACROSS OUR REGION SATURDAY. THERE
REMAINS SOME MODEL SPREAD WITH THE TRACK OF THE LOW ACROSS
MISSOURI/ILLINOIS BY SATURDAY...BUT THATS TO BE EXPECTED AT THIS
DISTANCE ESPECIALLY WITH LOWS EJECTING FROM THE SOUTHWESTERN STATES.
BOTH THE ECMWF AND GFS RUNS ARE A LITTLE FARTHER SOUTH THAN THOSE
FROM 24 HOURS AGO...THOUGH STILL APPEARS TO BE MAINLY A WARM/RAIN
EVENT FOR THE FORECAST AREA. CONTINUED TO FAVOR THE CONSISTENT ECMWF
SOLUTION FOR TIMING OF PRECIP/PRECIP TYPE FRIDAY NIGHT THROUGH
SATURDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* GENERALLY MVFR CIGS THROUGH LATE TONIGHT
* GUSTY SOUTHWEST WINDS TUESDAY
IZZI
//DISCUSSION...UPDATED 20Z...
COLD AIR MASS MOVING OVER AREA THAT HAD CLEARED OUT OVER SOUTHERN
WISCONSIN RESULTED IN MVFR CIGS FILLING BACK IN...SO NOW EXPECT
MVFR CIGS TO LINGER THROUGH LATE TONIGHT BEFORE POSSIBLE
SCATTERING OUT TOWARD DAYBREAK. THERE MAY BE SOME GRADUAL LOWERING
OF CIG HEIGHT AFTER DARK...BUT NOT EXPECTING PREVAILING CIGS
BELOW 1500 FT AT TAF SITES. CANT RULE OUT SCT FLURRIES FROM TIME
TO TIME...BUT NO OPERATIONAL IMPACT.
FROM 18Z...
FRONTAL BOUNDARY CURRENTLY PUSHING THROUGH CHICAGO TERMINALS WITH
MVFR VSBY IN -SN AT MDW AS OF THIS WRITING. SNOW SHOWERS AND
SIMILAR VSBY RESTRICTION EXPECTED AS BOUNDARY PUSHES SOUTH THROUGH
GYY AND TERMINALS SOUTH OF CHICAGO AREA...WITH FLURRIES/SHSN
ENDING FROM NORTH BEHIND BOUNDARY AND WINDS TURNING NORTHWEST.
CLEARING HOLE IN SATELLITE OVER WISCONSIN CONTINUES TO PUSH
SOUTHWARD AS WELL...WITH A PERIOD OF MVFR CIGS BEFORE SCATTERING
OUT TO VFR AT LEAST BRIEFLY. CONCERN THAT CLEARING HOLE IS SHOWING
SIGNS OF FILLING BACK IN WITH MVFR CIGS AND COMBINING WITH ANOTHER
AREA OF MVFR CIGS DROPPING SOUTHWARD FROM NORTHERN WISCONSIN...SO
WILL ASSESS AND MAY NEED TO INCLUDE AN MVFR CIG IN 20Z UPDATE.
WINDS WILL DIMINISH AND BECOME LIGHT WEST LATE TONIGHT AND THEN
SOUTHWEST BEFORE DAYBREAK AS HIGH PRESSURE RIDGE SETTLES SOUTH OF
AREA. PRESSURE GRADIENT WILL TIGHTEN MID DAY TUESDAY AS A LOW
PRESSURE SYSTEM TRACKS NORTH OF GREAT LAKES...CAUSING SOUTHWEST
WINDS AT 220-240 DEG DIRECTION TO INCREASE. FORECAST SOUNDINGS
SUGGEST POTENTIAL FOR GUSTS IN THE UPPER TEENS TO AROUND 20 KT
THROUGH EARLY EVENING TOMORROW BEFORE MIXING DIMINISHES.
RC
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN GENERALLY MVFR CIGS BUT SOME FLUCTUATIONS TO
VFR POSSIBLE
* MEDIUM CONFIDENCE IN TIMING OF CLEARING LATE TONIGHT
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT THROUGH FRIDAY...VFR. WX NIL.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE OF RAIN. MVFR/IFR
CONDITIONS POSSIBLE.
SUNDAY...CHANCE OF RAIN...SNOW MIX. MVFR/IFR CONDITIONS POSSIBLE.
KREIN
&&
.MARINE...
313 PM CST
N AND NE WINDS WILL DIMINISH TONIGHT AS LOW PRESSURE IN SW QUEBEC
MOVES E TO THE GULF OF SAINT LAWRENCE OVERNIGHT ALLOWING HIGH
PRESSURE OVER ONTARIO TO DROP SSE TO THE LOWER GREAT LAKES. S AND
SW WINDS WILL BE ON THE INCREASE TUE AS THE HIGH MERGES WITH
ANOTHER HIGH PRESSURE RIDGE OVER THE SOUTHERN PLAINS...OZARKS AND
LOWER OH VALLEY. WINDS SLACKEN AGAIN OVERNIGHT TUE BEFORE
FRESHENING AGAIN DURING WED AS LOW PRESSURE IN THE NORTHERN HIGH
PLAINS ELONGATES ACROSS THE UPPER MIDWEST INTO ONTARIO BY THU.
WINDS MAY REACH GALE FORCE BY WED NIGHT ON NORTHERN LAKE MI...AND
PERSIST INTO THU. THE LOW PRESSURE TROUGH DROPS S ACROSS THE GREAT
LAKES FRI WHILE LOW PRESSURE DEEPENS AS IT MOVES E FROM THE
CENTRAL ROCKIES TO THE CENTRAL PLAINS FRI AND FRI NIGHT. THIS LOW
TURNS NE TO THE MID MS VALLEY SAT AND MOVES INTO THE UPPER GREAT
LAKES SAT NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
314 PM CST MON DEC 10 2012
.DISCUSSION...
302 PM CST
SURFACE TROUGH EXTENDS WEST-EAST FROM ABOUT KRPJ TO KMDW AND OVER
INTO BERRIEN COUNTY MICHIGAN PER 20Z ANALYSIS. SCATTERED SNOW
SHOWERS HAVE BEEN CONFINED TO THE VICINITY OF THE TROUGH AXIS FOR
THE MOST PART THIS AFTERNOON...WITH SOMEWHAT HEAVIER SNOW SHOWERS
OVER LAKE MICHIGAN EXTENDING INTO FAR NORTHEAST PORTER AND LAPORTE
COUNTIES. WHILE A FEW OF THE SNOW SHOWERS OVER NORTHERN IL HAVE
PRODUCED RADAR RETURNS NEAR 35 DBZ AT TIMES...IT APPEARS THE
POTENTIAL FOR PICKING UP ANY MEASURABLE SNOW OF ANY SIGNIFICANCE IS
QUITE LOW. WITH THE BOUNDARY SAFELY SOUTH OF BOTH RFD AND ORD...AND
BOTH LOCATIONS ONLY PICKING UP TRACE AMOUNTS OF SNOW TODAY...IT
LOOKS AS IF THE STREAK OF DAYS WITHOUT MEASURABLE SNOW WILL CONTINUE
PAST 280 DAYS! THUS UNLESS SOMETHING ODD OCCURS...CHICAGO WILL VERY
LIKELY SET A NEW RECORD OF 281 CONSECUTIVE DAYS WITHOUT MEASURABLE
SNOW.
AS COLDER AIR CONTINUES TO SPREAD ACROSS LAKE MICHIGAN THIS
EVENING...LAKE EFFECT SNOW SHOWERS SHOULD BECOME MORE ORGANIZED WITH
NORTH-SOUTH BANDING DEVELOPING OVER MID AND EASTERN LAKE MICHIGAN.
LATEST HIGH-RES GUIDANCE INCLUDING WRF-NMM...WRF-NAM AND RAP RUNS
ALL SUGGEST THAT PORTIONS OF PORTER COUNTY MAY SEE A BRIEF PERIOD OF
LAKE EFFECT INTO THIS EVENING...BEFORE BOUNDARY LAYER WINDS BACK
MORE WESTERLY AFTER MIDNIGHT AND PUSH THE LOW LEVEL CONVERGENT FOCUS
EAST TOWARD THE MICHIGAN SHORE. CURRENT LAKE-ENHANCED BAND OVER FAR
SOUTHERN LAKE MICHIGAN HAS PRODUCED VISIBILITY AS LOW AS 1/2SM-1/4SM
AT SOUTH BEND IN THE LAST HOUR OR SO...AN INDICATION THAT SOME
RELATIVELY HEAVY SNOW MAY FALL FOR AT LEAST A SHORT TIME. 850 HPA
TEMPS COOLING TO AROUND -9C...AND RESULTING LAKE-850 HPA DELTA T
VALUES AROUND 16/17C WOULD POTENTIALLY SUPPORT 1-3/2-4 INCHES IF IT
WERE ABLE TO FOCUS ON A LOCALE FOR A FEW HOURS. GIVEN TRANSIENT
NATURE AND RELATIVELY SHORT DURATION EXPECTED FOR BAND TO REALLY
FOCUS ON NORTHEAST PORTER COUNTY...WOULD THINK THAT THE LOWER END OF
THIS RANGE IS MORE LIKELY THROUGH MIDNIGHT TONIGHT. AGAIN...SNOW
SHOULD END FOR PORTER COUNTY BY 06-09Z TONIGHT AS THE FOCUS DRIFTS
EAST OF THE AREA.
OTHERWISE...CONSIDERABLE AREA OF STRATUS/STRATOCU NOTED PER
AFTERNOON VISIBLE SATELLITE IMAGERY WITHIN LOW LEVEL COLD ADVECTION
BENEATH BROAD UPPER TROUGH WITH SERIES OF WEAK VORTS TRANSITING THE
REGION THROUGH TUESDAY. CLOUDS/FEW FLURRIES THIS AFTERNOON SHOULD
GRADUALLY TRANSITION TO PARTLY CLOUDY CONDITIONS FROM THE WEST LATE
TONIGHT/EARLY TUESDAY...WITH LARGE SCALE UPPER TROUGH AXIS FINALLY
MOVING EAST OF THE AREA TUESDAY NIGHT. BROAD...FLAT UPPER RIDGING
THEN BUILDS ACROSS THE GREAT LAKES AND SOUTHEAST WEDNESDAY/THURSDAY
WITH A PERIOD OF DRY AND SLOWLY MODERATING WEATHER.
NEXT WEATHER MAKER TO MONITOR IS AN UPPER TROUGH CURRENTLY
PROPAGATING ACROSS THE GULF OF ALASKA. MEDIUM RANGE GUIDANCE REMAINS
CONSISTENT IN DIGGING THIS SYSTEM SOUTH ALONG THE WEST COAST THROUGH
MID-WEEK...DEVELOPING INTO A CLOSED LOW ALONG THE CALIFORNIA COAST
BY LATE THURSDAY. THIS SYSTEM IS THEN PROGGED TO MOVE OUT ACROSS THE
PLAINS FRIDAY/FRIDAY NIGHT AND ACROSS OUR REGION SATURDAY. THERE
REMAINS SOME MODEL SPREAD WITH THE TRACK OF THE LOW ACROSS
MISSOURI/ILLINOIS BY SATURDAY...BUT THATS TO BE EXPECTED AT THIS
DISTANCE ESPECIALLY WITH LOWS EJECTING FROM THE SOUTHWESTERN STATES.
BOTH THE ECMWF AND GFS RUNS ARE A LITTLE FARTHER SOUTH THAN THOSE
FROM 24 HOURS AGO...THOUGH STILL APPEARS TO BE MAINLY A WARM/RAIN
EVENT FOR THE FORECAST AREA. CONTINUED TO FAVOR THE CONSISTENT ECMWF
SOLUTION FOR TIMING OF PRECIP/PRECIP TYPE FRIDAY NIGHT THROUGH
SATURDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ANY BRIEF VFR/HIGHER END MVFR TO LOWER BACK TO CIGS BETWEEN 015
AND 020 THROUGH THIS EVENING.
* GUSTY SOUTHWEST WINDS 220-240 DEG ON TUESDAY...WITH GUSTS
POSSIBLY UP TO 20 KT.
RC
//DISCUSSION...UPDATED 20Z...
COLD AIR MASS MOVING OVER AREA THAT HAD CLEARED OUT OVER SOUTHERN
WISCONSIN RESULTED IN MVFR CIGS FILLING BACK IN...SO NOW EXPECT
MVFR CIGS TO LINGER THROUGH LATE TONIGHT BEFORE POSSIBLE
SCATTERING OUT TOWARD DAYBREAK. THERE MAY BE SOME GRADUAL LOWERING
OF CIG HEIGHT AFTER DARK...BUT NOT EXPECTING PREVAILING CIGS
BELOW 1500 FT AT TAF SITES. CANT RULE OUT SCT FLURRIES FROM TIME
TO TIME...BUT NO OPERATIONAL IMPACT.
FROM 18Z...
FRONTAL BOUNDARY CURRENTLY PUSHING THROUGH CHICAGO TERMINALS WITH
MVFR VSBY IN -SN AT MDW AS OF THIS WRITING. SNOW SHOWERS AND
SIMILAR VSBY RESTRICTION EXPECTED AS BOUNDARY PUSHES SOUTH THROUGH
GYY AND TERMINALS SOUTH OF CHICAGO AREA...WITH FLURRIES/SHSN
ENDING FROM NORTH BEHIND BOUNDARY AND WINDS TURNING NORTHWEST.
CLEARING HOLE IN SATELLITE OVER WISCONSIN CONTINUES TO PUSH
SOUTHWARD AS WELL...WITH A PERIOD OF MVFR CIGS BEFORE SCATTERING
OUT TO VFR AT LEAST BRIEFLY. CONCERN THAT CLEARING HOLE IS SHOWING
SIGNS OF FILLING BACK IN WITH MVFR CIGS AND COMBINING WITH ANOTHER
AREA OF MVFR CIGS DROPPING SOUTHWARD FROM NORTHERN WISCONSIN...SO
WILL ASSESS AND MAY NEED TO INCLUDE AN MVFR CIG IN 20Z UPDATE.
WINDS WILL DIMINISH AND BECOME LIGHT WEST LATE TONIGHT AND THEN
SOUTHWEST BEFORE DAYBREAK AS HIGH PRESSURE RIDGE SETTLES SOUTH OF
AREA. PRESSURE GRADIENT WILL TIGHTEN MID DAY TUESDAY AS A LOW
PRESSURE SYSTEM TRACKS NORTH OF GREAT LAKES...CAUSING SOUTHWEST
WINDS AT 220-240 DEG DIRECTION TO INCREASE. FORECAST SOUNDINGS
SUGGEST POTENTIAL FOR GUSTS IN THE UPPER TEENS TO AROUND 20 KT
THROUGH EARLY EVENING TOMORROW BEFORE MIXING DIMINISHES.
RC
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN MVFR CIGS THROUGH THIS EVENING...WITH CURRENT
BRIEF VFR AT MDW EXPECTED TO LOWER BACK TO MVFR SHORTLY.
* MEDIUM TO HIGH CONFIDENCE CIGS WILL REMAIN ABOVE 1500 FT.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT THROUGH FRIDAY...VFR. WX NIL.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE OF RAIN. MVFR/IFR
CONDITIONS POSSIBLE.
SUNDAY...CHANCE OF RAIN...SNOW MIX. MVFR/IFR CONDITIONS POSSIBLE.
KREIN
&&
.MARINE...
313 PM CST
N AND NE WINDS WILL DIMINISH TONIGHT AS LOW PRESSURE IN SW QUEBEC
MOVES E TO THE GULF OF SAINT LAWRENCE OVERNIGHT ALLOWING HIGH
PRESSURE OVER ONTARIO TO DROP SSE TO THE LOWER GREAT LAKES. S AND
SW WINDS WILL BE ON THE INCREASE TUE AS THE HIGH MERGES WITH
ANOTHER HIGH PRESSURE RIDGE OVER THE SOUTHERN PLAINS...OZARKS AND
LOWER OH VALLEY. WINDS SLACKEN AGAIN OVERNIGHT TUE BEFORE
FRESHENING AGAIN DURING WED AS LOW PRESSURE IN THE NORTHERN HIGH
PLAINS ELONGATES ACROSS THE UPPER MIDWEST INTO ONTARIO BY THU.
WINDS MAY REACH GALE FORCE BY WED NIGHT ON NORTHERN LAKE MI...AND
PERSIST INTO THU. THE LOW PRESSURE TROUGH DROPS S ACROSS THE GREAT
LAKES FRI WHILE LOW PRESSURE DEEPENS AS IT MOVES E FROM THE
CENTRAL ROCKIES TO THE CENTRAL PLAINS FRI AND FRI NIGHT. THIS LOW
TURNS NE TO THE MID MS VALLEY SAT AND MOVES INTO THE UPPER GREAT
LAKES SAT NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
302 PM CST MON DEC 10 2012
.DISCUSSION...
302 PM CST
SURFACE TROUGH EXTENDS WEST-EAST FROM ABOUT KRPJ TO KMDW AND OVER
INTO BERRIEN COUNTY MICHIGAN PER 20Z ANALYSIS. SCATTERED SNOW
SHOWERS HAVE BEEN CONFINED TO THE VICINITY OF THE TROUGH AXIS FOR
THE MOST PART THIS AFTERNOON...WITH SOMEWHAT HEAVIER SNOW SHOWERS
OVER LAKE MICHIGAN EXTENDING INTO FAR NORTHEAST PORTER AND LAPORTE
COUNTIES. WHILE A FEW OF THE SNOW SHOWERS OVER NORTHERN IL HAVE
PRODUCED RADAR RETURNS NEAR 35 DBZ AT TIMES...IT APPEARS THE
POTENTIAL FOR PICKING UP ANY MEASURABLE SNOW OF ANY SIGNIFICANCE IS
QUITE LOW. WITH THE BOUNDARY SAFELY SOUTH OF BOTH RFD AND ORD...AND
BOTH LOCATIONS ONLY PICKING UP TRACE AMOUNTS OF SNOW TODAY...IT
LOOKS AS IF THE STREAK OF DAYS WITHOUT MEASURABLE SNOW WILL CONTINUE
PAST 280 DAYS! THUS UNLESS SOMETHING ODD OCCURS...CHICAGO WILL VERY
LIKELY SET A NEW RECORD OF 281 CONSECUTIVE DAYS WITHOUT MEASURABLE
SNOW.
AS COLDER AIR CONTINUES TO SPREAD ACROSS LAKE MICHIGAN THIS
EVENING...LAKE EFFECT SNOW SHOWERS SHOULD BECOME MORE ORGANIZED WITH
NORTH-SOUTH BANDING DEVELOPING OVER MID AND EASTERN LAKE MICHIGAN.
LATEST HIGH-RES GUIDANCE INCLUDING WRF-NMM...WRF-NAM AND RAP RUNS
ALL SUGGEST THAT PORTIONS OF PORTER COUNTY MAY SEE A BRIEF PERIOD OF
LAKE EFFECT INTO THIS EVENING...BEFORE BOUNDARY LAYER WINDS BACK
MORE WESTERLY AFTER MIDNIGHT AND PUSH THE LOW LEVEL CONVERGENT FOCUS
EAST TOWARD THE MICHIGAN SHORE. CURRENT LAKE-ENHANCED BAND OVER FAR
SOUTHERN LAKE MICHIGAN HAS PRODUCED VISIBILITY AS LOW AS 1/2SM-1/4SM
AT SOUTH BEND IN THE LAST HOUR OR SO...AN INDICATION THAT SOME
RELATIVELY HEAVY SNOW MAY FALL FOR AT LEAST A SHORT TIME. 850 HPA
TEMPS COOLING TO AROUND -9C...AND RESULTING LAKE-850 HPA DELTA T
VALUES AROUND 16/17C WOULD POTENTIALLY SUPPORT 1-3/2-4 INCHES IF IT
WERE ABLE TO FOCUS ON A LOCALE FOR A FEW HOURS. GIVEN TRANSIENT
NATURE AND RELATIVELY SHORT DURATION EXPECTED FOR BAND TO REALLY
FOCUS ON NORTHEAST PORTER COUNTY...WOULD THINK THAT THE LOWER END OF
THIS RANGE IS MORE LIKELY THROUGH MIDNIGHT TONIGHT. AGAIN...SNOW
SHOULD END FOR PORTER COUNTY BY 06-09Z TONIGHT AS THE FOCUS DRIFTS
EAST OF THE AREA.
OTHERWISE...CONSIDERABLE AREA OF STRATUS/STRATOCU NOTED PER
AFTERNOON VISIBLE SATELLITE IMAGERY WITHIN LOW LEVEL COLD ADVECTION
BENEATH BROAD UPPER TROUGH WITH SERIES OF WEAK VORTS TRANSITING THE
REGION THROUGH TUESDAY. CLOUDS/FEW FLURRIES THIS AFTERNOON SHOULD
GRADUALLY TRANSITION TO PARTLY CLOUDY CONDITIONS FROM THE WEST LATE
TONIGHT/EARLY TUESDAY...WITH LARGE SCALE UPPER TROUGH AXIS FINALLY
MOVING EAST OF THE AREA TUESDAY NIGHT. BROAD...FLAT UPPER RIDGING
THEN BUILDS ACROSS THE GREAT LAKES AND SOUTHEAST WEDNESDAY/THURSDAY
WITH A PERIOD OF DRY AND SLOWLY MODERATING WEATHER.
NEXT WEATHER MAKER TO MONITOR IS AN UPPER TROUGH CURRENTLY
PROPAGATING ACROSS THE GULF OF ALASKA. MEDIUM RANGE GUIDANCE REMAINS
CONSISTENT IN DIGGING THIS SYSTEM SOUTH ALONG THE WEST COAST THROUGH
MID-WEEK...DEVELOPING INTO A CLOSED LOW ALONG THE CALIFORNIA COAST
BY LATE THURSDAY. THIS SYSTEM IS THEN PROGGED TO MOVE OUT ACROSS THE
PLAINS FRIDAY/FRIDAY NIGHT AND ACROSS OUR REGION SATURDAY. THERE
REMAINS SOME MODEL SPREAD WITH THE TRACK OF THE LOW ACROSS
MISSOURI/ILLINOIS BY SATURDAY...BUT THATS TO BE EXPECTED AT THIS
DISTANCE ESPECIALLY WITH LOWS EJECTING FROM THE SOUTHWESTERN STATES.
BOTH THE ECMWF AND GFS RUNS ARE A LITTLE FARTHER SOUTH THAN THOSE
FROM 24 HOURS AGO...THOUGH STILL APPEARS TO BE MAINLY A WARM/RAIN
EVENT FOR THE FORECAST AREA. CONTINUED TO FAVOR THE CONSISTENT ECMWF
SOLUTION FOR TIMING OF PRECIP/PRECIP TYPE FRIDAY NIGHT THROUGH
SATURDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ANY BRIEF VFR/HIGHER END MVFR TO LOWER BACK TO CIGS BETWEEN 015
AND 020 THROUGH THIS EVENING.
* GUSTY SOUTHWEST WINDS 220-240 DEG ON TUESDAY...WITH GUSTS
POSSIBLY UP TO 20 KT.
RC
//DISCUSSION...UPDATED 20Z...
COLD AIR MASS MOVING OVER AREA THAT HAD CLEARED OUT OVER SOUTHERN
WISCONSIN RESULTED IN MVFR CIGS FILLING BACK IN...SO NOW EXPECT
MVFR CIGS TO LINGER THROUGH LATE TONIGHT BEFORE POSSIBLE
SCATTERING OUT TOWARD DAYBREAK. THERE MAY BE SOME GRADUAL LOWERING
OF CIG HEIGHT AFTER DARK...BUT NOT EXPECTING PREVAILING CIGS
BELOW 1500 FT AT TAF SITES. CANT RULE OUT SCT FLURRIES FROM TIME
TO TIME...BUT NO OPERATIONAL IMPACT.
FROM 18Z...
FRONTAL BOUNDARY CURRENTLY PUSHING THROUGH CHICAGO TERMINALS WITH
MVFR VSBY IN -SN AT MDW AS OF THIS WRITING. SNOW SHOWERS AND
SIMILAR VSBY RESTRICTION EXPECTED AS BOUNDARY PUSHES SOUTH THROUGH
GYY AND TERMINALS SOUTH OF CHICAGO AREA...WITH FLURRIES/SHSN
ENDING FROM NORTH BEHIND BOUNDARY AND WINDS TURNING NORTHWEST.
CLEARING HOLE IN SATELLITE OVER WISCONSIN CONTINUES TO PUSH
SOUTHWARD AS WELL...WITH A PERIOD OF MVFR CIGS BEFORE SCATTERING
OUT TO VFR AT LEAST BRIEFLY. CONCERN THAT CLEARING HOLE IS SHOWING
SIGNS OF FILLING BACK IN WITH MVFR CIGS AND COMBINING WITH ANOTHER
AREA OF MVFR CIGS DROPPING SOUTHWARD FROM NORTHERN WISCONSIN...SO
WILL ASSESS AND MAY NEED TO INCLUDE AN MVFR CIG IN 20Z UPDATE.
WINDS WILL DIMINISH AND BECOME LIGHT WEST LATE TONIGHT AND THEN
SOUTHWEST BEFORE DAYBREAK AS HIGH PRESSURE RIDGE SETTLES SOUTH OF
AREA. PRESSURE GRADIENT WILL TIGHTEN MID DAY TUESDAY AS A LOW
PRESSURE SYSTEM TRACKS NORTH OF GREAT LAKES...CAUSING SOUTHWEST
WINDS AT 220-240 DEG DIRECTION TO INCREASE. FORECAST SOUNDINGS
SUGGEST POTENTIAL FOR GUSTS IN THE UPPER TEENS TO AROUND 20 KT
THROUGH EARLY EVENING TOMORROW BEFORE MIXING DIMINISHES.
RC
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN MVFR CIGS THROUGH THIS EVENING...WITH CURRENT
BRIEF VFR AT MDW EXPECTED TO LOWER BACK TO MVFR SHORTLY.
* MEDIUM TO HIGH CONFIDENCE CIGS WILL REMAIN ABOVE 1500 FT.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT THROUGH FRIDAY...VFR. WX NIL.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...CHANCE OF RAIN. MVFR/IFR
CONDITIONS POSSIBLE.
SUNDAY...CHANCE OF RAIN...SNOW MIX. MVFR/IFR CONDITIONS POSSIBLE.
KREIN
&&
.MARINE...
300 AM CST
THE TWO SEPARATE LOW PRESSURE SYSTEM THAT PASSED THROUGH THE
REGION EARLIER SUNDAY EVENING HAVE MERGED INTO A CONSOLIDATED LOW
OVER THE EASTER GREAT LAKES...WHICH WILL CONTINUE TO DEEPEN
SLIGHTLY AS IT TRACKS INTO SOUTHERN ONTARIO. THIS WILL LEAD TO
WINDS BECOMING GENERALLY NORTHERLY OVER THE LAKE AT AROUND 25 TO
30 KT. A SECONDARY SURGE OF COLDER AIR MOVING DOWN THE LAKE MAY
BRING A BRIEF PERIOD WHERE THERE MAY BE A FEW GALE FORCE GUSTS
BEFORE SUNRISE. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS
THE LAKE LATE TONIGHT AND TUESDAY AS A WEAK LOW PRESSURE SYSTEM
TRACKS ACROSS SOUTHERN CANADA. WINDS WILL GRADUALLY BECOME
SOUTHWESTERLY BY TUESDAY NIGHT AND WEDNESDAY. WITH HIGH PRESSURE
PERSISTING OVER THE OHIO VALLEY FROM TUESDAY THROUGH THURSDAY AND
A SERIES OF WEAK LOW PRESSURE SYSTEMS TRACK ACROSS THE NORTHERN
PLAINS AND UPPER GREAT LAKES...GENERALLY SOUTHWESTERLY WINDS WILL
REMAIN IN THE 25-30KT RANGE.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
259 PM EST MON DEC 10 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EST MON DEC 10 2012
A WEAK WAVE MOVING THROUGH THE AREA TODAY COULD PROMPT A
FEW SNOWFLAKES ACROSS THE NORTHERN COUNTIES. TONIGHT HIGH PRESSURE
WILL BUILD INTO THE AREA AND BRING DRY WEATHER WHICH WILL LAST
THROUGH FRIDAY. BY FRIDAY NIGHT ANOTHER SYSTEM WILL APPROACH THE
AREA AND BRING CHANCES FOR RAIN THAT WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1153 AM EST MON DEC 10 2012
LOWERED MAX TEMPS SIGNIFICANTLY IN THE NORTHWEST IN THE
UPDATE...AS WE HAVE LIKELY ALREADY REACHED OUR HIGHS THERE WITH
OVERCAST SKIES AND STRONG COLD ADVECTION ONGOING. THIS IS LIKELY
THE CASE IN THE SOUTHEAST AS WELL...BUT TEMPS THERE WERE ALREADY
NEAR MAXES. TEMPS LIKELY TO FALL GRADUALLY INTO THE AFTERNOON.
KEPT SLIGHT CHANCE POPS IN THE NORTH BUT EXPANDED FLURRY CHANCES
ACROSS THE ENTIRE FORECAST AREA...AS ALL RAP FORECAST SOUNDINGS
SHOW AT LEAST A BRIEF PERIOD OF SATURATION IN THE SNOW GROWTH
LAYER THIS AFTERNOON...AND REGIONAL MOSAICS ALREADY SHOW SOME
RETURNS UPSTREAM WITH FLURRIES REACHING THE GROUND AT AT LEAST A
FEW SITES IN SOUTHERN ILLINOIS AND WESTERN KENTUCKY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 355 AM EST MON DEC 10 2012
FORECAST FOCUS IS ON TEMPERATURES. MODELS IN GOOD AGREEMENT SO WILL
USE A CONSENSUS. TONIGHT AN UPPER WAVE WILL BE MAKING IT/S EXIT OF
THE AREA. WITH LAKE ENHANCEMENT STILL BRIEFLY AVAILABLE INCLUDED
SOME FLURRIES IN THE NORTHEAST AS IT LEAVES. AFTER THAT HIGH
PRESSURE BUILDS IN FOR THE REMAINDER OF THE SHORT TERM BRINGING WITH
IT CLEARING SKIES FROM ON TUESDAY AND THEN MOSTLY CLEAR THROUGH THE
SHORT TERM AND SLOWLY WARMING TEMPERATURES AFTER TUESDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 259 PM EST MON DEC 10 2012
OHIO VALLEY WILL BE ON THE BACK SIDE OF BROAD HIGH PRESSURE RIDGE
ACROSS MUCH OF THE EASTERN U S TO END THE WORK WEEK...KEEPING DRY
WEATHER ACROSS CENTRAL INDIANA. MODEL GUIDANCE IS IN BETTER
AGREEMENT THIS AFTERNOON WITH RESPECT TO THE APPROACH AND IMPACTS AS
A SHARP UPPER WAVE EJECTS OUT OF THE PACIFIC COAST TROUGH AND MOVES
INTO THE MIDWEST. ECMWF REMAINS THE MOST CONSISTENT WITH THE TRACK
OF THIS SYSTEM...WITH A GRADUALLY SLOWING OF THE IMPACTS AS A DEEPER
SYSTEM LIKELY TO NOT MOVE INTO THE REGION UNTIL SATURDAY AFTERNOON/
NIGHT.
ECMWF HAS THE SUPPORT OF THE OP GFS/UKMET/GFS ENSEMBLE MEAN WITH THE
GGEM THE ONLY SUBSTANTIAL OUTLIER. FEEL COMFORTABLE IN SLOWING
PRECIP ONSET TO LATE FRIDAY NIGHT ACROSS THE WEST...WITH MOST
LOCATIONS NOT SEEING ANY RAINFALL UNTIL SATURDAY AS THE SYSTEM MOVES
INTO THE MID MISSISSIPPI VALLEY. WILL CARRY POPS FOR SATURDAY
THROUGH SUNDAY WITH HIGHEST POPS FOCUSED ON SATURDAY AFTERNOON.
SHOULD MODEL TRENDS CONTINUE TO SLOW THE SYSTEM...MAY NEED TO RAISE
POPS FOR SATURDAY NIGHT AND SUNDAY MORNING FURTHER.
COLDER AIR WILL SPILL BACK INTO THE REGION SUNDAY AND CONTINUING
INTO EARLY NEXT WEEK AS THE LOW TRANSITIONS TO A COASTAL SYSTEM AND
MOVES SLOWLY INTO NEW ENGLAND THROUGH THE PERIOD. THIS
SOUTHWEST FLOW WILL BRING MILD TEMPS FOR MID DECEMBER WITH HIGHS IN
THE UPPER 40S/LOWER 50S FOR FRIDAY AND SATURDAY...WITH TEMPERATURES
RETURNING INTO THE LOWER AND MIDDLE 40S FOR SUNDAY AND MONDAY.
&&
.AVIATION /DISCUSSION FOR 101800Z TAF ISSUANCE/...
ISSUED AT 1217 PM EST MON DEC 10 2012
MVFR CEILINGS WILL CONTINUE THROUGH THE EVENING...WITH SKIES
CLEARING LATE TONIGHT.
MVFR STRATUS DECK WITH CEILINGS AT 1000-1500FT EXTENDING WEST OF
THE MISSISSIPPI RIVER EARLY THIS AFTERNOON. WITH AN UPPER WAVE
ALOFT STILL TO PASS ACROSS THE REGION THROUGH THE LATE AFTERNOON
AND EVENING...EXPECT LOWER CEILINGS WILL IMPACT ALL TERMINALS
INTO THE OVERNIGHT. MAY SEE A FEW FLURRIES AS WELL INTO THE
EVENING HOURS WITH KLAF STANDING THE GREATEST CHANCE AT SEEING
FLAKES. AT THIS POINT...DO NOT FORESEE ANY VISIBILITY RESTRICTIONS
FROM ANY FLURRIES/LIGHT SNOW SHOWERS. NORTHWEST WINDS WILL
CONTINUE AT 10-15KTS THROUGH SUNSET WITH SPORADIC HIGHER GUSTS.
SURFACE RIDGING WILL EXPAND INTO THE OHIO VALLEY OVERNIGHT WITH
LOW LEVEL FLOW BACKING TO A MORE WESTERLY DIRECTION AND LIGHTENING
BELOW 10KTS. MODEL SOUNDINGS AND RH PROGS INDICATE THAT LOWER
CEILINGS WILL DEPART BETWEEN 06-12Z TUESDAY FROM ALL OF THE
TERMINALS AS DRIER AIR ADVECTS INTO THE REGION. SKIES SHOULD BE
MAINLY CLEAR ON TUESDAY WITH FLOW BACKING TO A SOUTHWEST DIRECTION
AS THE HIGH PRESSURE RIDGE SETS UP OVER THE TENNESSEE AND LOWER
MISSISSIPPI VALLEYS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
247 PM EST MON DEC 10 2012
.SHORT TERM...
DIFFICULT PD EARLY ON GIVEN SCOPE OF DVLPG LK RESPONSE. SFC TROUGH
ACRS NRN CONTS TO DROP SWD AND EMBOLDENING A BROADER RESPONSE
UNDERNEATH BALLOONING MID LVL MSTR PLUME. BRIEF PD OF FZDZ AND
PERHAPS SLEET AT ONSET BUT QUICKLY CHANGING OVR TO SHSN N-S TIMED
W/ARRIVAL OF LK MSTR ENTRAINMENT PLUME AND DEEPENING CAA WEDGE.
PRIMARY PROB THIS EVENING IS TEA KETTLE LK SETUP AND DENOTED QUITE
WELL IN RUC13 AND OTHER HIGHRES GUIDANCE. LK SP CONNECTION NOTED
THIS AFTN WITHIN FVRBLY VEERED LONG AXIS CYCLONIC FETCH AS SEEN IN
VIS IMAGERY AND SUSPECT LK CONVERGENCE ZONE WILL ABRUPTLY BLOSSOM
AFT SUNSET IN TANDEM W/MAXIMIZING LL THERMAL TROUGH OF WHICH MAY
LEAD TO A BRIEF PD OF SIG LK EFFECT SNOWFALL CNTRD THROUGH EXTREME
SW BERRIEN...NRN LAPORTE AND WRN ST JOE COUNTIES. TEMPTED TO
CONSIDER AN ADVISORY BUT GIVEN UPSTREAM LK DVLPMNTS HAVE YET TO
PLAY THEIR CARD...CONFIDENCE LACKING. WILL CONT TO MONITOR AND
PASS CONCERNS ONWARD.
OTRWS LG SCALE SFC RIDGE WILL BUILD ALG THE APPALACHIAN SPINE
THROUGH THE END OF THE PD AS WK SECONDARY SYS DIPS THROUGH SRN
ONTARIO. LL FLW BACKS ABRUPTLY LT TONIGHT TO WRLY W/DWINDLING LK
EFFECT LIFTING OUT BFR BACKING FURTHER TO SWRLY ON TUE. THIS WILL
YIELD SW-NE CLRG W/SOME INSOLATION HELPING TO BOOST TEMPS A BIT
WARMER THAN TDA.
&&
.LONG TERM...WEDNESDAY THROUGH MONDAY.
ENERGY CURRENTLY IN THE GULF OF ALASKA WILL DIG ALONG THE PACIFIC
COAST THROUGH THE UPCOMING WEEK...REACHING CALIFORNIA BY THURSDAY.
THIS WILL ALLOW FOR INCREASING HGTS WITH A SEMI ZONAL FLOW TO SET UP
THROUGH FRIDAY. TEMPS ARE EXPECTED TO MODERATE TO ABOVE NORMAL
LEVELS IN THE 40S.
LEE SIDE CYCLOGENESIS WILL TAKE PLACE STARTING LATE FRIDAY WITH THE
SYSTEM EJECTING TOWARDS THE GREAT LAKES. MODELS VARYING SOMEWHAT ON
TIMING AND OVERALL TRACK...BUT SEEM TO POINT TOWARDS THE FORECAST
AREA BEING ON THE WARM SIDE ONCE AGAIN...YIELDING RAIN CHANCES FOR
THE WEEKEND FOLLOWED BY A MIXTURE OF RAIN/SNOW IN ITS WAKE. PREV
GRIDS HAD DECENT HANDLE ON TRENDS. ONLY CHANGES MADE WAS TO BREAK UP
WITH SOMEWHAT MORE DETAIL TO TRY TO ADD SOME TIMING TO BETTER
CHANCES OF PRECIP. QUICK SHOT OF COLD AIR WILL ARRIVE BEHIND THE
SYSTEM...BUT NOTHING SUBSTANTIALLY COLDER WITH A RETURN TO NEAR OR
SLIGHTLY BELOW NORMAL READINGS.
ENERGIZED PATTERN WILL CONTINUE OUTSIDE THE LONG TERM PERIOD WITH
NEXT SYSTEM ALREADY TAKING SHAPE OVER TEXAS BY MONDAY NIGHT. ECMWF
OVER THE PAST SEVERAL RUNS HAS HINTED THAT THIS COULD BRING A DECENT
SHOT OF ACCUMULATING SNOWFALL TO THE REGION BOTH IN ADVANCE OF THE
SYSTEM AND WITH WHAT COULD BE A PERSISTENT DEFORMATION ZONE AS THE
LOW CUTS OFF SOMEWHERE IN THE EASTERN GREAT LAKES. PLENTY OF TIME TO
WATCH AT THIS POINT CONSIDERING STILL A WAYS TO GO.
&&
.AVIATION...
MOST DIFFICULT NR TERM W/ONGOING MID LVL SATURATION OVERTOP CONTD
MOIST BNDRY LYR. GENERAL TREND LAST 2 HOURS IS FOR GRADUAL MIST
DVLPMNT IN ASSOCN/W BNDRY LYR BASED ASCENT. HWVR XPC SOME SEEDING FM
ALOFT TO OCCUR TWD MID AFTN WHICH WILL PROMOTE A PD OF -DZ OR -RA
BFR CHANGING OVR THIS EVENING AS LL CAA WEDGE DEEPENS. THUS HAVE
ROLLED THE DICE AGAINST GUIDANCE W/CAT IFR CONDS GIVING WAY TO SVRL
HR PD OF LIFR CONDS AT KSBN COINCIDENT W/LK INDUCED SHSN. KFWA SHLD
HOLD IN IFR CAT THROUGH EARLY EVE BUT SOME IMPROVEMENT XPCD
OVERNIGHT INBEHIND SFC TROUGH PIVOTING SWD ACRS THE AREA THIS AFTN.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...FISHER
AVIATION...T
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1217 PM EST MON DEC 10 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EST MON DEC 10 2012
A WEAK WAVE MOVING THROUGH THE AREA TODAY COULD PROMPT A
FEW SNOWFLAKES ACROSS THE NORTHERN COUNTIES. TONIGHT HIGH PRESSURE
WILL BUILD INTO THE AREA AND BRING DRY WEATHER WHICH WILL LAST
THROUGH FRIDAY. BY FRIDAY NIGHT ANOTHER SYSTEM WILL APPROACH THE
AREA AND BRING CHANCES FOR RAIN THAT WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1153 AM EST MON DEC 10 2012
LOWERED MAX TEMPS SIGNIFICANTLY IN THE NORTHWEST IN THE
UPDATE...AS WE HAVE LIKELY ALREADY REACHED OUR HIGHS THERE WITH
OVERCAST SKIES AND STRONG COLD ADVECTION ONGOING. THIS IS LIKELY
THE CASE IN THE SOUTHEAST AS WELL...BUT TEMPS THERE WERE ALREADY
NEAR MAXES. TEMPS LIKELY TO FALL GRADUALLY INTO THE AFTERNOON.
KEPT SLIGHT CHANCE POPS IN THE NORTH BUT EXPANDED FLURRY CHANCES
ACROSS THE ENTIRE FORECAST AREA...AS ALL RAP FORECAST SOUNDINGS
SHOW AT LEAST A BRIEF PERIOD OF SATURATION IN THE SNOW GROWTH
LAYER THIS AFTERNOON...AND REGIONAL MOSAICS ALREADY SHOW SOME
RETURNS UPSTREAM WITH FLURRIES REACHING THE GROUND AT AT LEAST A
FEW SITES IN SOUTHERN ILLINOIS AND WESTERN KENTUCKY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 355 AM EST MON DEC 10 2012
FORECAST FOCUS IS ON TEMPERATURES. MODELS IN GOOD AGREEMENT SO WILL
USE A CONSENSUS. TONIGHT AN UPPER WAVE WILL BE MAKING IT/S EXIT OF
THE AREA. WITH LAKE ENHANCEMENT STILL BRIEFLY AVAILABLE INCLUDED
SOME FLURRIES IN THE NORTHEAST AS IT LEAVES. AFTER THAT HIGH
PRESSURE BUILDS IN FOR THE REMAINDER OF THE SHORT TERM BRINGING WITH
IT CLEARING SKIES FROM ON TUESDAY AND THEN MOSTLY CLEAR THROUGH THE
SHORT TERM AND SLOWLY WARMING TEMPERATURES AFTER TUESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 305 AM EST MON DEC 10 2012
MAIN FOCUS TO THE EXTENDED WILL BE ON TIMING AND COVERAGE OF POPS
ACROSS CENTRAL INDIANA ASSOCIATED WITH A STRONG WEEKEND SYSTEM.
MODELS HAVE LARGE DIFFERENCES ON TIMING AND STRENGTH OF THE
AFOREMENTIONED STRONG UPPER AND SURFACE SYSTEMS...HOWEVER THE 00Z
ECMWF AND CANADIAN ARE THE CLOSEST WITH THE LATTER JUST A TOUCH
FASTER. BOTH WERE SHOWING NEGATIVELY TILTED UPPER TROUGHS AND SUB
1000 MILLIBAR SURFACE LOWS MOVING TO NEAR SOUTHERN LAKE MICHIGAN
LATE SATURDAY. REGARDLESS...ALL MODELS ARE SUGGESTING CHANCE POPS
ESPECIALLY WEST FRIDAY NIGHT WITH WIDESPREAD ACTIVITY ON SATURDAY
AND THEN LESSENING CHANCES SATURDAY NIGHT AND SUNDAY AS THE SYSTEM
LIFTS NORTHEAST INTO SOUTHEASTERN CANADA. REGIONAL INITIALIZATION
REFLECTS THIS WITH LIKELY POPS ON SATURDAY AND LESSER CHANCES FRIDAY
NIGHT AND SATURDAY NIGHT INTO SUNDAY. SO...WILL NOT MAKE ANY
CHANGES.
THE EXTENDED WILL START OFF WITH SURFACE HIGH PRESSURE ACROSS THE
SOUTHEASTERN STATES AND INCREASING SOUTHWEST FLOW ACROSS THE OHIO
VALLEY AHEAD OF THE AFOREMENTIONED WEATHER MAKER. THIS WILL ALLOW
FOR ABOVE NORMAL TEMPERATURES CLIMAXING ON SATURDAY IN THE UPPER 40S
NORTH AND LOWER 50S SOUTH. BEHIND THE FRONT...TEMPERATURES WILL BE
NEAR NORMAL. WILL ACCEPT REGIONAL INITIALIZATION TEMPERATURES
ESPECIALLY WITH THE MODEL DIFFERENCES IN PLAY.
&&
.AVIATION /DISCUSSION FOR 101800Z TAF ISSUANCE/...
ISSUED AT 1217 PM EST MON DEC 10 2012
MVFR CEILINGS WILL CONTINUE THROUGH THE EVENING...WITH SKIES
CLEARING LATE TONIGHT.
MVFR STRATUS DECK WITH CEILINGS AT 1000-1500FT EXTENDING WEST OF
THE MISSISSIPPI RIVER EARLY THIS AFTERNOON. WITH AN UPPER WAVE
ALOFT STILL TO PASS ACROSS THE REGION THROUGH THE LATE AFTERNOON
AND EVENING...EXPECT LOWER CEILINGS WILL IMPACT ALL TERMINALS
INTO THE OVERNIGHT. MAY SEE A FEW FLURRIES AS WELL INTO THE
EVENING HOURS WITH KLAF STANDING THE GREATEST CHANCE AT SEEING
FLAKES. AT THIS POINT...DO NOT FORESEE ANY VISIBILITY RESTRICTIONS
FROM ANY FLURRIES/LIGHT SNOW SHOWERS. NORTHWEST WINDS WILL
CONTINUE AT 10-15KTS THROUGH SUNSET WITH SPORADIC HIGHER GUSTS.
SURFACE RIDGING WILL EXPAND INTO THE OHIO VALLEY OVERNIGHT WITH
LOW LEVEL FLOW BACKING TO A MORE WESTERLY DIRECTION AND LIGHTENING
BELOW 10KTS. MODEL SOUNDINGS AND RH PROGS INDICATE THAT LOWER
CEILINGS WILL DEPART BETWEEN 06-12Z TUESDAY FROM ALL OF THE
TERMINALS AS DRIER AIR ADVECTS INTO THE REGION. SKIES SHOULD BE
MAINLY CLEAR ON TUESDAY WITH FLOW BACKING TO A SOUTHWEST DIRECTION
AS THE HIGH PRESSURE RIDGE SETS UP OVER THE TENNESSEE AND LOWER
MISSISSIPPI VALLEYS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....MK
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1154 AM EST MON DEC 10 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EST MON DEC 10 2012
A WEAK WAVE MOVING THROUGH THE AREA TODAY COULD PROMPT A
FEW SNOWFLAKES ACROSS THE NORTHERN COUNTIES. TONIGHT HIGH PRESSURE
WILL BUILD INTO THE AREA AND BRING DRY WEATHER WHICH WILL LAST
THROUGH FRIDAY. BY FRIDAY NIGHT ANOTHER SYSTEM WILL APPROACH THE
AREA AND BRING CHANCES FOR RAIN THAT WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1153 AM EST MON DEC 10 2012
LOWERED MAX TEMPS SIGNIFICANTLY IN THE NORTHWEST IN THE
UPDATE...AS WE HAVE LIKELY ALREADY REACHED OUR HIGHS THERE WITH
OVERCAST SKIES AND STRONG COLD ADVECTION ONGOING. THIS IS LIKELY
THE CASE IN THE SOUTHEAST AS WELL...BUT TEMPS THERE WERE ALREADY
NEAR MAXES. TEMPS LIKELY TO FALL GRADUALLY INTO THE AFTERNOON.
KEPT SLIGHT CHANCE POPS IN THE NORTH BUT EXPANDED FLURRY CHANCES
ACROSS THE ENTIRE FORECAST AREA...AS ALL RAP FORECAST SOUNDINGS
SHOW AT LEAST A BRIEF PERIOD OF SATURATION IN THE SNOW GROWTH
LAYER THIS AFTERNOON...AND REGIONAL MOSAICS ALREADY SHOW SOME
RETURNS UPSTREAM WITH FLURRIES REACHING THE GROUND AT AT LEAST A
FEW SITES IN SOUTHERN ILLINOIS AND WESTERN KENTUCKY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 355 AM EST MON DEC 10 2012
FORECAST FOCUS IS ON TEMPERATURES. MODELS IN GOOD AGREEMENT SO WILL
USE A CONSENSUS. TONIGHT AN UPPER WAVE WILL BE MAKING IT/S EXIT OF
THE AREA. WITH LAKE ENHANCEMENT STILL BRIEFLY AVAILABLE INCLUDED
SOME FLURRIES IN THE NORTHEAST AS IT LEAVES. AFTER THAT HIGH
PRESSURE BUILDS IN FOR THE REMAINDER OF THE SHORT TERM BRINGING WITH
IT CLEARING SKIES FROM ON TUESDAY AND THEN MOSTLY CLEAR THROUGH THE
SHORT TERM AND SLOWLY WARMING TEMPERATURES AFTER TUESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 305 AM EST MON DEC 10 2012
MAIN FOCUS TO THE EXTENDED WILL BE ON TIMING AND COVERAGE OF POPS
ACROSS CENTRAL INDIANA ASSOCIATED WITH A STRONG WEEKEND SYSTEM.
MODELS HAVE LARGE DIFFERENCES ON TIMING AND STRENGTH OF THE
AFOREMENTIONED STRONG UPPER AND SURFACE SYSTEMS...HOWEVER THE 00Z
ECMWF AND CANADIAN ARE THE CLOSEST WITH THE LATTER JUST A TOUCH
FASTER. BOTH WERE SHOWING NEGATIVELY TILTED UPPER TROUGHS AND SUB
1000 MILLIBAR SURFACE LOWS MOVING TO NEAR SOUTHERN LAKE MICHIGAN
LATE SATURDAY. REGARDLESS...ALL MODELS ARE SUGGESTING CHANCE POPS
ESPECIALLY WEST FRIDAY NIGHT WITH WIDESPREAD ACTIVITY ON SATURDAY
AND THEN LESSENING CHANCES SATURDAY NIGHT AND SUNDAY AS THE SYSTEM
LIFTS NORTHEAST INTO SOUTHEASTERN CANADA. REGIONAL INITIALIZATION
REFLECTS THIS WITH LIKELY POPS ON SATURDAY AND LESSER CHANCES FRIDAY
NIGHT AND SATURDAY NIGHT INTO SUNDAY. SO...WILL NOT MAKE ANY
CHANGES.
THE EXTENDED WILL START OFF WITH SURFACE HIGH PRESSURE ACROSS THE
SOUTHEASTERN STATES AND INCREASING SOUTHWEST FLOW ACROSS THE OHIO
VALLEY AHEAD OF THE AFOREMENTIONED WEATHER MAKER. THIS WILL ALLOW
FOR ABOVE NORMAL TEMPERATURES CLIMAXING ON SATURDAY IN THE UPPER 40S
NORTH AND LOWER 50S SOUTH. BEHIND THE FRONT...TEMPERATURES WILL BE
NEAR NORMAL. WILL ACCEPT REGIONAL INITIALIZATION TEMPERATURES
ESPECIALLY WITH THE MODEL DIFFERENCES IN PLAY.
&&
.AVIATION /DISCUSSION FOR THE 10/15Z TAF UPDATE/...
ISSUED AT 932 AM EST MON DEC 10 2012
ADDED TEMPO GROUPS TO IND/BMG FOR BRIEF DROPS INTO HIGH END IFR
TERRITORY ON CEILINGS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 440 AM EST MON DEC 10 2012
MVFR CEILINGS EXPECTED THROUGH MUCH OF THE TAF PERIOD IMPROVING TO
VFR AFTER 07Z TUESDAY. COULD ALSO SEE A FEW AFTERNOON FLURRIES AS A
WEAK UPPER WAVE MOVES THROUGH. OTHERWISE...NORTHWEST WINDS AT 10
KNOTS OR SO WILL DROP BELOW 10 KNOTS AFTER 00Z. WINDS AND MUCH DRIER
AIR WILL PREVENT ANY VISIBILITY RESTRICTIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....MK
AVIATION...MK/NIELD
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1028 AM MST MON DEC 10 2012
.UPDATE...
ISSUED AT 922 AM MST MON DEC 10 2012
EXPIRED WIND CHILL ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
04Z WATER VAPOR IMAGERY INDICATED TROUGH AXIS CENTERED OVER THE
CWA WITH BROAD RIDGING ACROSS THE WEST COAST. RAP DYNAMIC TROPOPAUSE
ANALYSIS INDICATED SHORT WAVE TROUGH MOVING OVER MONTANA...BUT DID
NOT APPEAR TO BE MUCH OF A RESPONSE ON WV IMAGERY. AT THE
SFC...RIDGE AXIS WAS LOCATED ALONG A KITR TO KANW LINE WITH
TEMPERATURES ALREADY IN THE SINGLE DIGITS ACROSS THE AREA.
MAIN SHORT TERM CONCERNS WILL BE WIND CHILLS THIS MORNING FOLLOWED
BY HOW QUICKLY TEMPERATURES RECOVER THROUGH THE MIDDLE OF THE WEEK.
EARLY MORNING HOURS...TEMPS HAVE FALLEN TO SEVERAL DEGREES BELOW
ZERO ACROSS NORTHEAST CWA WITH WINDS AROUND 10 MPH CREATING WIND
CHILLS IN THE -15 TO -20 RANGE. ALTHOUGH SOME SLIGHT WARMING HAS
BEEN NOTED ACROSS EASTERN COLORADO IN RESPONSE TO CONTINUED WESTERLY
FLOW/WAA...WILL LIKELY BE SEVERAL HOURS BEFORE THAT HAS A MEANINGFUL
IMPACT ACROSS NORTHEAST CWA. ALTHOUGH WINDS ARE NOT STRONG...THINK
CURRENT TEMPS WARRANT A WIND CHILL ADVISORY FOR THE MORNING HOURS.
WHILE CONDITIONS HAVE ALREADY OCCURRED ACROSS EASTERN
COLORADO...AFOREMENTIONED WARMING TREND IN OBS LEADS ME TO THINK
THREAT NOT GREAT IN THIS AREA.
TODAY...WEAK SHORT WAVE TROUGH WILL APPROACH FROM THE NORTH THIS
MORNING...BUT WITH VERY STABLE CONDITIONS EXPECTED FROM NEAR TERM
MODELS AND 00Z OBSERVATIONS AM DOUBTFUL THAT THIS INITIAL TROUGH WILL
DO MORE THAN CREATE A FEW HIGH CLOUDS THROUGH THE MORNING HOURS.
MAIN ISSUE TODAY WILL BE THE GUSTY WINDS THIS AFTERNOON AND HOW
QUICKLY TDS RECOVER FROM INITIAL VERY LOW VALUES AS POTENTIAL EXISTS
FOR LOW END CRITICAL FIRE WEATHER CONDITIONS TODAY. WINDS WILL PICK
UP INTO THE 15 TO 25 MPH RANGE DURING THE AFTERNOON...BUT THINK TDS
WILL ACTUALLY RISE SEVERAL DEGREES WITH VERTICAL MIXING. CURRENT
THOUGHTS KEEP THE HIGHEST WINDS AND DRIEST HUMIDITIES NOT VERY
COLOCATED AND WITH POTENTIAL FOR RISING AFTERNOON TDS...DO NOT PLAN
ON ISSUING A RFW AT THE MOMENT.
TONIGHT-TOMORROW...1.5 PVU FIELDS INDICATE SEVERAL SMALL SCALE SHORT
WAVE TROUGHS MOVING THROUGH THE FLOW TONIGHT...WITH STRONGEST (AT
LEAST FROM A PV PERSPECTIVE) COMING THROUGH THE CWA ON TUESDAY. GFS
AND NAM DIFFER ON STABILITY PROFILES OVERNIGHT WITH GFS INDICATING A
POCKET OF NEAR NEUTRAL CONDITIONS ACROSS WESTERN CWA BETWEEN 0 AND
06Z. WHILE NAM IS SLIGHTLY MORE STABLE...POINT SOUNDINGS DO INDICATE
SNOW GROWTH ZONE NOT TO FAR ABOVE THE SURFACE WITH A PERIOD OF ASCENT
MAXIMIZED IN THIS AREA. DO NOT THINK LIFT WILL BE ENOUGH FOR
MEANINGFUL PRECIP...BUT A FLURRY OR TWO DOES NOT LOOK UNREASONABLE.
DESPITE AN APPARENTLY STRONGER TROUGH ON TUESDAY...NEAR GROUND SNOW
GROWTH ZONE DISAPPEARS AND OVERALL PROFILES ARE MUCH MORE
STABLE...SO DO NOT EXPECT FLURRIES TO CARRY ON THROUGH THE DAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
TUESDAY NIGHT-WEDNESDAY NIGHT...QUIET WEATHER EXPECTED FOR THE
PERIOD AS SHORT WAVE RIDGING WILL BUILD OVER THE AREA AS FLOW
BECOMES MORE AMPLIFIED IN RESPONSE TO TROUGH DEVELOPING OVER WEST
COAST. THINK A RAPID WARM UP IS POSSIBLE...WITH TEMPS APPROACHING
UPPER 50S TO LOW 60S BY WEDNESDAY. AM A LITTLE CONCERNED THAT
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ON WEDNESDAY AS
DEWPOINTS WILL REMAIN FAIRLY LOW AND NOT UNHEARD OF FOR DEVELOPING
LEE TROUGH TO BRING GUSTY WINDS. RIGHT NOW...THINGS LOOK TOO
MARGINAL FOR POTENTIAL WATCH...BUT WILL KEEP AN EYE ON AS PERIOD
APPROACHES.
THURSDAY-MONDAY...
SW FLOW WILL BE IN PLACE THURSDAY AS DEEP TROUGH DEVELOPS OVER THE
WESTERN US...WHICH SHOULD KEEP CONDITIONS MILD AND DRY OVER THE CWA.
HIGHS SHOULD BE A LITTLE COOLER FROM THE HIGHS ON WED...HOWEVER MOST
LOCATIONS SHOULD STILL BE IN THE MID 50S.
OPERATIONAL GUIDANCE IS IN DECENT AGREEMENT ON GENERAL TIMING/TRACK
OF TROUGH AS IS MOVES FROM THE SW US AND ACROSS SOUTHERN KANSAS
FRIDAY THROUGH SATURDAY...WITH CLOSED CENTER MOVING ACROSS SOUTHERN
KS. THIS COULD PUT OUR EASTERN CWA NEAR POSSIBLE DEFORMATION
ZONE/HEAVY SNOW BAND FRIDAY NIGHT. GEFS ENSEMBLES STILL SHOWING
GREATER SPREAD WITH GEFS MEAN MUCH SLOWER AND LESS AMPLIFIED AS A
RESULT. THERE HASNT BE A LOT OF RUN TO RUN CONTINUITY THE LAST FEW
DAYS...SO A LOT CAN STILL CHANGE CONSIDERING THE TIME RANGE. BASED
ON CURRENT RUNS IT DOES APPEAR CHANCES FOR A WINTER STORM DEVELOPING
OVER PARTS OF KANSAS COULD BE INCREASING. FOR OUR CWA THE FAVORED
LOCATIONS WOULD BE ACROSS THE EAST WHERE LIGHT SNOW ACCUMULATIONS
ARE POSSIBLE. I DID INCREASE POPS TO 40 ACROSS THE EAST THIS
FORECAST CYCLE...WITH CONFIDENCE TOO LOW TO GO MUCH HIGHER.
THERE IS SIGNIFICANT SPREAD IN THE UPPER LEVEL PATTERN AFTER THIS
SYSTEM SHIFTS EAST. GEFS AND GFS ARE GENERALLY SHOWING A
WESTERLY/ZONAL PATTERN ...WHILE ECMWF IS TRYING TO SHOW A MUCH MORE
PROGRESSIVE/ACTIVE PATTERN. REGARDLESS OF SOLUTION IT DOES APPEAR
THE ACTIVE STORM TRACK IS FAVORING AREAS OUTSIDE OF OUR CWA...SO IM
KEEPING LATER PERIODS DRY FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1026 AM MST MON DEC 10 2012
VFR EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF PERIOD.
SCATTERED MID LEVEL CLOUDS WILL ACCOMPANY A WEAK SHORTWAVE TROUGH
THROUGH THIS EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...024
SHORT TERM...JRM
LONG TERM...JRM/DR
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
923 AM MST MON DEC 10 2012
.UPDATE...
ISSUED AT 922 AM MST MON DEC 10 2012
EXPIRED WIND CHILL ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
04Z WATER VAPOR IMAGERY INDICATED TROUGH AXIS CENTERED OVER THE
CWA WITH BROAD RIDGING ACROSS THE WEST COAST. RAP DYNAMIC TROPOPAUSE
ANALYSIS INDICATED SHORT WAVE TROUGH MOVING OVER MONTANA...BUT DID
NOT APPEAR TO BE MUCH OF A RESPONSE ON WV IMAGERY. AT THE
SFC...RIDGE AXIS WAS LOCATED ALONG A KITR TO KANW LINE WITH
TEMPERATURES ALREADY IN THE SINGLE DIGITS ACROSS THE AREA.
MAIN SHORT TERM CONCERNS WILL BE WIND CHILLS THIS MORNING FOLLOWED
BY HOW QUICKLY TEMPERATURES RECOVER THROUGH THE MIDDLE OF THE WEEK.
EARLY MORNING HOURS...TEMPS HAVE FALLEN TO SEVERAL DEGREES BELOW
ZERO ACROSS NORTHEAST CWA WITH WINDS AROUND 10 MPH CREATING WIND
CHILLS IN THE -15 TO -20 RANGE. ALTHOUGH SOME SLIGHT WARMING HAS
BEEN NOTED ACROSS EASTERN COLORADO IN RESPONSE TO CONTINUED WESTERLY
FLOW/WAA...WILL LIKELY BE SEVERAL HOURS BEFORE THAT HAS A MEANINGFUL
IMPACT ACROSS NORTHEAST CWA. ALTHOUGH WINDS ARE NOT STRONG...THINK
CURRENT TEMPS WARRANT A WIND CHILL ADVISORY FOR THE MORNING HOURS.
WHILE CONDITIONS HAVE ALREADY OCCURRED ACROSS EASTERN
COLORADO...AFOREMENTIONED WARMING TREND IN OBS LEADS ME TO THINK
THREAT NOT GREAT IN THIS AREA.
TODAY...WEAK SHORT WAVE TROUGH WILL APPROACH FROM THE NORTH THIS
MORNING...BUT WITH VERY STABLE CONDITIONS EXPECTED FROM NEAR TERM
MODELS AND 00Z OBSERVATIONS AM DOUBTFUL THAT THIS INITIAL TROUGH WILL
DO MORE THAN CREATE A FEW HIGH CLOUDS THROUGH THE MORNING HOURS.
MAIN ISSUE TODAY WILL BE THE GUSTY WINDS THIS AFTERNOON AND HOW
QUICKLY TDS RECOVER FROM INITIAL VERY LOW VALUES AS POTENTIAL EXISTS
FOR LOW END CRITICAL FIRE WEATHER CONDITIONS TODAY. WINDS WILL PICK
UP INTO THE 15 TO 25 MPH RANGE DURING THE AFTERNOON...BUT THINK TDS
WILL ACTUALLY RISE SEVERAL DEGREES WITH VERTICAL MIXING. CURRENT
THOUGHTS KEEP THE HIGHEST WINDS AND DRIEST HUMIDITIES NOT VERY
COLOCATED AND WITH POTENTIAL FOR RISING AFTERNOON TDS...DO NOT PLAN
ON ISSUING A RFW AT THE MOMENT.
TONIGHT-TOMORROW...1.5 PVU FIELDS INDICATE SEVERAL SMALL SCALE SHORT
WAVE TROUGHS MOVING THROUGH THE FLOW TONIGHT...WITH STRONGEST (AT
LEAST FROM A PV PERSPECTIVE) COMING THROUGH THE CWA ON TUESDAY. GFS
AND NAM DIFFER ON STABILITY PROFILES OVERNIGHT WITH GFS INDICATING A
POCKET OF NEAR NEUTRAL CONDITIONS ACROSS WESTERN CWA BETWEEN 0 AND
06Z. WHILE NAM IS SLIGHTLY MORE STABLE...POINT SOUNDINGS DO INDICATE
SNOW GROWTH ZONE NOT TO FAR ABOVE THE SURFACE WITH A PERIOD OF ASCENT
MAXIMIZED IN THIS AREA. DO NOT THINK LIFT WILL BE ENOUGH FOR
MEANINGFUL PRECIP...BUT A FLURRY OR TWO DOES NOT LOOK UNREASONABLE.
DESPITE AN APPARENTLY STRONGER TROUGH ON TUESDAY...NEAR GROUND SNOW
GROWTH ZONE DISAPPEARS AND OVERALL PROFILES ARE MUCH MORE
STABLE...SO DO NOT EXPECT FLURRIES TO CARRY ON THROUGH THE DAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 AM MST MON DEC 10 2012
TUESDAY NIGHT-WEDNESDAY NIGHT...QUIET WEATHER EXPECTED FOR THE
PERIOD AS SHORT WAVE RIDGING WILL BUILD OVER THE AREA AS FLOW
BECOMES MORE AMPLIFIED IN RESPONSE TO TROUGH DEVELOPING OVER WEST
COAST. THINK A RAPID WARM UP IS POSSIBLE...WITH TEMPS APPROACHING
UPPER 50S TO LOW 60S BY WEDNESDAY. AM A LITTLE CONCERNED THAT
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ON WEDNESDAY AS
DEWPOINTS WILL REMAIN FAIRLY LOW AND NOT UNHEARD OF FOR DEVELOPING
LEE TROUGH TO BRING GUSTY WINDS. RIGHT NOW...THINGS LOOK TOO
MARGINAL FOR POTENTIAL WATCH...BUT WILL KEEP AN EYE ON AS PERIOD
APPROACHES.
THURSDAY-MONDAY...
SW FLOW WILL BE IN PLACE THURSDAY AS DEEP TROUGH DEVELOPS OVER THE
WESTERN US...WHICH SHOULD KEEP CONDITIONS MILD AND DRY OVER THE CWA.
HIGHS SHOULD BE A LITTLE COOLER FROM THE HIGHS ON WED...HOWEVER MOST
LOCATIONS SHOULD STILL BE IN THE MID 50S.
OPERATIONAL GUIDANCE IS IN DECENT AGREEMENT ON GENERAL TIMING/TRACK
OF TROUGH AS IS MOVES FROM THE SW US AND ACROSS SOUTHERN KANSAS
FRIDAY THROUGH SATURDAY...WITH CLOSED CENTER MOVING ACROSS SOUTHERN
KS. THIS COULD PUT OUR EASTERN CWA NEAR POSSIBLE DEFORMATION
ZONE/HEAVY SNOW BAND FRIDAY NIGHT. GEFS ENSEMBLES STILL SHOWING
GREATER SPREAD WITH GEFS MEAN MUCH SLOWER AND LESS AMPLIFIED AS A
RESULT. THERE HASNT BE A LOT OF RUN TO RUN CONTINUITY THE LAST FEW
DAYS...SO A LOT CAN STILL CHANGE CONSIDERING THE TIME RANGE. BASED
ON CURRENT RUNS IT DOES APPEAR CHANCES FOR A WINTER STORM DEVELOPING
OVER PARTS OF KANSAS COULD BE INCREASING. FOR OUR CWA THE FAVORED
LOCATIONS WOULD BE ACROSS THE EAST WHERE LIGHT SNOW ACCUMULATIONS
ARE POSSIBLE. I DID INCREASE POPS TO 40 ACROSS THE EAST THIS
FORECAST CYCLE...WITH CONFIDENCE TOO LOW TO GO MUCH HIGHER.
THERE IS SIGNIFICANT SPREAD IN THE UPPER LEVEL PATTERN AFTER THIS
SYSTEM SHIFTS EAST. GEFS AND GFS ARE GENERALLY SHOWING A
WESTERLY/ZONAL PATTERN ...WHILE ECMWF IS TRYING TO SHOW A MUCH MORE
PROGRESSIVE/ACTIVE PATTERN. REGARDLESS OF SOLUTION IT DOES APPEAR
THE ACTIVE STORM TRACK IS FAVORING AREAS OUTSIDE OF OUR CWA...SO IM
KEEPING LATER PERIODS DRY FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 437 AM MST MON DEC 10 2012
VFR CONDITIONS EXPECTED OVER THE NEXT 24 HOURS WITH GUSTY WEST
WINDS EXPECTED TODAY WITH PERIODS OF SCATTERED TO BROKEN MID LEVEL
CLOUDS. OVERNIGHT CEILINGS WILL FALL TO AROUND 3500 FEET...BUT
WIDESPREAD AND PERSISTENT FLIGHT RESTRICTIONS ARE NOT EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...024
SHORT TERM...JRM
LONG TERM...JRM/DR
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
302 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION WEST OF THE BLUE RIDGE LATE
THIS AFTERNOON...AND THEN CROSS THE REMAINDER OF THE AREA EARLY TONIGHT.
HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT THROUGH WEDNESDAY
NIGHT...AND REMAIN THROUGH THE END OF THE WEEK. &&
.NEAR TERM /THROUGH TONIGHT/...
AT 18Z...COLD FRONT HAS MOVED EAST OF KPIT BUT HAS NOT MADE IT TO
W MD. BOTH THE 12Z NAM AND GFS HAVE VERY SIMILAR TIMINGS WITH
FROPA LATE AFTERNOON IN WESTERN HALF OF CWA...IN THE I-95 CORRIDOR EARLY
EVENING 00Z-02Z AND THEN FOR THE CHESAPEAKE BAY SHORTLY AFTER MIDNIGHT.
PCPN WITH THIS FRONT WILL DIMINISH AS IT MOVES ACROSS THE MOUNTAINS
AS NEGATIVE DIFFERENTIAL VORTICITY ADV AS INDICATED IN THE 12Z GFS
H5 FIELDS WILL NOT ADD ITS COMPONENT TO UPWARD MOTION COUPLED WITH AMPLE
NEG MOISTURE ADVECTION IN THE MID LEVELS. SO WHILE MUCH OF THE
AREA WILL SEE SHOWERS WITH THE FROPA...THEY WILL BE ON THE LIGHTER
SIDE. PCPN WILL NOT EXIT THE SE CWA UNTIL LATE TONIGHT. WINDS WILL
BE GUSTY BEHIND THE FRONT TONIGHT.
IN THE WESTERN UPSLOPE REGION...SNOW SHOWERS ARE LIKELY STARTING
AROUND MIDNIGHT AND LASTING UNTIL MID TUE MORNING. SNOW ACCUM
SHOULD BE AROUND ONE INCH WELL UNDER SNOW ADVSRY LEVELS.
&&
.SHORT TERM /TUESDAY/...
THE FRONT HANGS UP A BIT IN THE EARLY MORNING IN THE
SOUTHEASTERNMOST PORTION OF OUR CWA...WHICH WILL CAUSE CLOUDS TO
LINGER BUT I BELIEVE THAT THE SHRA WILL BE EAST OF THE MD PORTION
OF THE BAY BY DAYBREAK.
ELSEWHERE...A SUNNY START BEFORE HIGH CLOUDS WORK INTO THE REGION
BY MIDDAY AS INDICATED BY RH 80% OR HIGHER AOA H4 STREAMING FROM
THE GULF OF MEXICO AND ALSO BEING IN THE RR QUAD OF UPPER LEVEL
JET. AREAS W OF I-81 WILL BE ON THE WESTERN FRINGE OF THESE HIGH
CLOUDS...AND MAY EVEN EXPERIENCE PRETTY MUCH MOSTLY SUNNY SKIES
ALL DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
SURFACE HIGH PRESSURE SETTLES OVER THE MID-ATLANTIC TUESDAY NIGHT
THROUGH THURSDAY. AN UPPER LEVEL DISTURBANCE EJECTS FROM THE THE
GULF STATES WEDNESDAY MORNING AND APPROACHES THE MID-ATLANTIC
WEDNESDAY NIGHT INTO THURSDAY. THE SYSTEM PASSES BY TO OUR SOUTH AS
SURFACE LOW PRESSURE IS SPAWNED UP OFF THE NORTH CAROLINA COAST
THURSDAY MORNING. THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS
IDEA. THE 12Z GFS HAS A FRONT EVEN A BIT FARTHER SOUTH THURSDAY
MORNING...KEEPING ANY PRECIPITATION OUT OF FAR SOUTHERN MARYLAND
THOUGH THERE WILL BE SOME CLOUD COVER FROM THIS. THE FLOW WILL BE LIGHT
OUT OF THE NORTH WEDNESDAY FOR COOLER AND DRIER AIR. THE NAM HAS
BACKED AWAY FROM AN EARLIER SUGGESTION OF AN EASTERLY FLOW WEDNESDAY
NIGHT AND THURSDAY. THURSDAY COULD SEE MORE SUNSHINE WITH A LITTLE
MILDER TEMPERATURES.
UPPER LOW PRESSURE OVER THE WESTERN STATES SPLITS AS A NORTHERN
BRANCH SYSTEM SWEEPS INTO THE PLAIN STATES SATURDAY MORNING. THIS
SYSTEM MAY PROGRESS INTO THE NORTHEAST STATES BY SUNDAY. FRIDAY
LOOKS DRY AND MILD WITH A LIGHT FLOW ALOFT AND PLENTY OF SUNSHINE.
CLOUDS MAY INCREASE SATURDAY AS THE WAVE APPROACHES. THE GFS SPREADS
SHOWERS INTO THE WESTERN MOUNTAINS BY AFTERNOON. GFS HAS THE SURFACE
LOW OVER OHIO SUNDAY MORNING WHILE THE EC HAS IT A BIT FARTHER
NORTH. THE EC DEVELOPS A 991MB LOW RIGHT OVER CENTRAL VA SUNDAY
NIGHT AND LIFTS IT UP THE COAST WHILE THE GFS BOMBS IT OUT WELL
OFFSHORE. THE DIFFERENCE IS A MUCH MORE AMPLIFIED JET BETWEEN THE
RIDGE OVER THE ATLANTIC AND THE WAVE. IN EITHER EVENT WE HAVE
INTRODUCED SHOWERS ACROSS THE AREA SATURDAY NIGHT AND CONTINUED
THEM INTI MONDAY FOR THE TIME BEING.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
CIGS/VSBY IN IFR-MVFR CATEGORY AHEAD OF FROPA...THEN A RAPID INCREASE TO
VFR CONDITIONS LATE TONIGHT THROUGH TUE ALONG WITH A GUSTY NW
WIND.
VFR CONDITIONS ARE LIKELY TO PERSIST AS SURFACE HIGH PRESSURE BUILDS
IN TUESDAY NIGHT INTO FRIDAY. A MID LEVEL OVC WILL MOVE OVERHEAD
WEDNESDAY AS A WAVE MOVES BY TO THE SOUTH. BREEZY NORTH WINDS TO 15
KTS ARE POSSIBLE WEDNESDAY...SHIFTING TO THE NE WEDNESDAY NIGHT. A
SOUTHWEST FLOW ALOFT WILL INCREASE FRIDAY AS A WEATHER SYSTEM
APPROACHES FROM THE OHIO VALLEY.
&&
.MARINE...
19Z OBS SHOWING FEW SCA GUSTS ON MAIN CHANNEL OF CHESSIE WITH WAA
PATTERN MAKING THE GUSTS DIFFICULT TO GET DOWN TO THE COLD WATER
SURFACE. WINDS WILL PICKUP TO SCA ACROSS ALL WATERS BEHIND FRONT
AND CONT SOLID SCA EARLY TUE BEFORE DIMINSHING TUE AFT.
SURFACE HIGH PRESSURE BUILDS OVER THE WATERS IN TUESDAY NIGHT INTO
FRIDAY. BREEZY NORTH WINDS MAY APPROACH SCA CRITERIA WEDNESDAY AS A
WEATHER DISTURBANCE PASSES BY TO THE SOUTH. LIGHT WINDS AND FAIR
WEATHER ARE ANTICIPATED THURSDAY AND FRIDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TUESDAY FOR ANZ530-531-538-
539.
SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR ANZ532>534-537-
540>543.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO NOON EST
TUESDAY FOR ANZ535-536.
&&
$$
SYNOPSIS...LEE
NEAR TERM...LEE
SHORT TERM...LEE
LONG TERM...SDG
AVIATION...SDG/LEE
MARINE...SDG/LEE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 PM EST MON DEC 10 2012
.UPDATE...
ISSUED AT 1151 AM EST MON DEC 10 2012
WENT AHEAD AND CANCELLED THE WINTER WEATHER ADVISORY FOR GOGEBIC
COUNTY. THE TRICKY PART IS THAT LIGHT TO MODERATE SNOW SHOWERS
CONTINUE TO ROTATE ACROSS FAR WESTERN LAKE SUPERIOR. HOWEVER...THE
LATEST RADAR TRENDS HAVE BEEN SHOWING STEADY OR A SLIGHT EASTWARD
PUSH TO THE BAND CLOSEST TO THE GOGEBIC SHORELINE. GIVEN THE LOW
TOPPED CLOUDS...ITS BEEN DIFFICULT TO SEE EXACTLY WHERE THE EASTERN
EXTENT OF THE SNOW BAND IS LOCATED...HOWEVER WEBCAMS OVER ONTONAGON
COUNTY DO NOT SHOW MUCH AND BACK UP THE IDEA OF CANCELING THE
ADVISORY. WILL CONTINUE TO MONITOR THE PROGRESS OF THE 850MB WIND
FOLLOWING SHOWERS OVER LAKE SUPERIOR. THE LATEST THINKING IS THAT
WITH 850MB WINDS BECOMING LIGHT AROUND 18Z...AND THEN PUSHING OUT OF
THE SW THROUGH LATE AFTERNOON...THAT SNOW MAY MOVE BACK TOWARD
ONTONAGON AND N HOUGHTON COUNTIES BY LATE AFTERNOON. WITH CONTINUED
LIGHT LAKE EFFECT SNOW SHOWERS...THE ADVISORY FOR MARQUETTE COUNTY
WILL BE ALLOWED TO EXPIRE AT 18Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 546 AM EST MON DEC 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM NW ONTARIO INTO THE SRN PLAINS. THE SHORTWAVE TROUGH THAT
BROUGHT HEAVY SNOW TO THE UPPER MS VALLEY SUNDAY HAS
SHEARED/WEAKENED AND LIFTED QUICKLY TO THE EAST OF UPPER MICHIGAN.
CYCLONIC NNE LOW LEVEL FLOW COMBINED WITH ABUNDANT 850-700 MB
MOISTURE AND 850 MB TEMPS TO ARUOND -11C SUPPORTED LAKE EFFECT SNOW
INTO N CNTRL UPPER MI. 850-700 MB FGEN AHEAD OF AN 850-700 MB
THERMAL TROUGH INTO NRN MN ALSO SUPPORTED SOME LIGHT SNOW OVER NE MN
AND HELPED ENHANCE THE LES INTO FAR NW WI. SO FAR...LAND BREEZE AND
LAKE INDUCED TROUGHING HAS KEPT THE MAIN LES BANDS WEST OF IWD
THROUGH 10Z.
MAIN FCST CONCERNS ARE LES TRENDS AND SNOW AMOUNTS.
TODAY...
SATELLITE TRENDS AND MODELS SUGGEST THAT ANY LINGERING
SYNOPTIC SCALE LIFT WILL DEPART EARLY TODAY WITH THE 850-700 MB
MOISUTRE ALSO THINNING OUT BY THIS AFTERNOON ALONG WITH ONLY A
GRADUAL BACKING TREND IN THE LOW LEVEL WIND FROM NE TO NORTH. THIS
SHOULD KEEP THE LES GOING INTO NORTH CENTRAL MICHIGAN GOING THIS
MORNING WITH LIGHT TO MODERATE SNOWFALL RATES...ESPECIALLY INTO
UPSLOPE FLOW LOCATIONS. THIS SHOULD PRODUCE AN ADDITIONAL 1 TO 3
INCHES OF SNOW MAINLY IN THE HIGHER TERRAIN LOCATIONS OF MARQUETTE
COUNTY FROM THE HURON MOUNTAINS TO NEGAUNEE/ISHPMEMING AND GWINN.
HIGH RES MODELS HAVE BEEN CONSISTENT IN GRADUALLY SHIFTING THE AXIS
OF LEVEL CONV AND BRINGING THE LES BANDS INTO WESTERN GOGEBIC COUNTY
BY AROUND 12Z. EVEN THOUGH THERE MAY SOME DELAY TO THE ONSET OF
HEAVIER SNOW IF THE TROUGH MOVEMENT IS SLOWER THAN EXPECTED...A
PERIOD OF MODERATE TO HEAVY SNOW VCNTY IWD COULD BRING AT LEAST 1 TO
4 INCHES OF SNOW. HOWEVER...CONFIDENCE IN THE TIMING/DURATION OF THE
HEAVIER BAND IS STILL LIMITED. AS A WEAK RIDGE BUILDS TOWARD THE AREA
THIS AFTERNOON AND WINDS/CONV WEAKENS...THE SNOW SHOULD DIMINISH OVER
BOTH THE WEST AND N CNTRL UPPER MI.
TONIGHT...
A A WEAK SHORTWAVE AND SFC TROUGH REFLECTION WILL APPROACH
THE AREA BRINGING A SHIFT TO SW TO S WINDS. THIS SHOULD PUSH ANY
REMANING LES FROM LAKE SUPERIOR OFFSHORE DURING THE EVENING. WITH
THE VERY WEAK WIND FIELDS...THERE IS THE POSSIBILITY THAT A
SHORELINE PARALLEL OR MESO-LOW BAND MAY BRUSH THE WEST UPPER MI
SHORELINE. A WEAK BAND 700-300 MB QVECTOR CONV AND ISENTROPIC LIFT
AHEAD OF THIS FEATURE MAY SUPPORT SOME LIGHT SNOW INTO WEST UPPER
MICHIGAN. HOWEVER...ONLY SLIGHT CHANCE POPS WERE MENTIONED.
INCREASING LOW LEVEL CONV SRLY FLOW OFF OF LAKE MICHIGAN MAY ALSO
BRING AN LES BAND INTO THE SE CWA LATE BUT SHOULD HOLD OFF MAINLY
UNTIL TUES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 546 AM EST MON DEC 10 2012
SURFACE RIDGE AXIS WILL BE EAST OF THE AREA BY TUESDAY MORNING. AS
NEXT UPPER TROUGH MOVES INTO WESTERN ONTARIO WITH ASSOCIATED WEAK
SURFACE LOW WINDS WILL BECOME SOUTHERLY ACROSS THE ENTIRE AREA. 85H
TEMPS WILL REMAIN LOW ENOUGH...-10 TO -12...TO SUPPORT A LAKE EFFECT
SNOW BAND OFF OF LAKE MICHIGAN INTO THE EASTERN U.P. WINDS WILL
SLOWLY BUT STEADILY VEER THROUGH THE DAY ALLOWING THE BAND TO BE
TRANSIENT FROM WEST TO EAST WHICH SHOULD LIMIT SNOWFALL AMOUNTS OVER
EASTERN SCHOOLCRAFT AND LUCE COUNTIES IN THE 1 TO AS MUCH AS 3 INCH
RANGE.
AS SURFACE LOW MOVES ACROSS ONTARIO...SURFACE TROUGH WILL CROSS LAKE
SUPERIOR ALLOWING WINDS TO BECOME WESTERLY AND 85H TEMPS TO FALL TO
-14 BRIEFLY OVER WESTERN LAKE SUPERIOR. EXPECT SOME LAKE EFFECT SNOW
TO AFFECT THE KEWEENAW PENINSULA TUE EVENING/TUE NIGHT BEFORE WARM
ADVECTION REGIME SETS IN ACROSS THE WESTERN LAKE.
SOUTHERLY WINDS WILL RETURN FOR WEDNESDAY INTO THURSDAY AS ANOTHER
WEAK DISTURBANCE SKIRTS BY JUST NORTH OF THE AREA. ANY FORCING FOR
PRECIPITATION SHOULD REMAIN OVER NORTHERN LAKE SUPERIOR INTO
ONTARIO. 85H TEMPS FOR WEDNESDAY AND THURSDAY WILL BE IN THE 0 TO -4
RANGE RESULTING IN DAYTIME TEMPERATURES A FEW DEGREES ABOVE NORMAL.
VERY LITTLE CONFIDENCE IN THE FORECAST BEYOND THURSDAY WITH MEDIUM
RANGE MODELS SHOWING LARGE SCALE DISCREPANCIES. ECMWF HAS BEEN
CONSISTENT IN HINTING AT A POTENTIAL STORM SYSTEM DEVELOPING OVER
THE PLAINS AND LIFTING INTO THE GREAT LAKES OVER THE WEEKEND WITH
THE GFS SHOWING HIGH PRESSURE OVER THE GREAT LAKES NEXT WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 129 PM EST MON DEC 10 2012
HIGH END IFR TO MVFR CEILINGS REMAIN CENTERED ACROSS UPPER MI EARLY
THIS AFTERNOON. HIGH PRESSURE PUSHING IN FROM THE N AND W WILL
SLOWLY ERODE LINGERING SNOW SHOWERS OFF LAKE SUPERIOR...AND BRING IN
VFR CEILINGS LATE TONIGHT. THE NEXT LOW PRESSURE SYSTEM WILL BE
EDGING EAST...TO ONTARIO AND W UPPER MI OVERNIGHT. AS A
RESULT...EXPECT LIGHT WINDS TO BECOME S AND INCREASE TO AROUND 10KTS
BY MID MORNING TUESDAY. BY 18Z THURSDAY THE TROUGH EXTENDING FROM
THE LOW WILL BE AROUND CMX AND IWD...WITH SLOWLY LOWERING CEILINGS
THROUGH THE DAY TUESDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 546 AM EST MON DEC 10 2012
NORTHERLY WINDS OF 20 TO 30 KNOTS EARLY TODAY ARE EXPECTED TO
DIMINISH AS A TROUGH TO THE SOUTH OF UPPER MICHIGAN GRADUALLY
WEAKENS AND SHIFTS TO THE SOUTHEAST. BEHIND THIS FEATURE...A SERIES
OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST
OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...KF
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1152 AM EST MON DEC 10 2012
.UPDATE...
ISSUED AT 1151 AM EST MON DEC 10 2012
WENT AHEAD AND CANCELLED THE WINTER WEATHER ADVISORY FOR GOGEBIC
COUNTY. THE TRICKY PART IS THAT LIGHT TO MODERATE SNOW SHOWERS
CONTINUE TO ROTATE ACROSS FAR WESTERN LAKE SUPERIOR. HOWEVER...THE
LATEST RADAR TRENDS HAVE BEEN SHOWING STEADY OR A SLIGHT EASTWARD
PUSH TO THE BAND CLOSEST TO THE GOGEBIC SHORELINE. GIVEN THE LOW
TOPPED CLOUDS...ITS BEEN DIFFICULT TO SEE EXACTLY WHERE THE EASTERN
EXTENT OF THE SNOW BAND IS LOCATED...HOWEVER WEBCAMS OVER ONTONAGON
COUNTY DO NOT SHOW MUCH AND BACK UP THE IDEA OF CANCELING THE
ADVISORY. WILL CONTINUE TO MONITOR THE PROGRESS OF THE 850MB WIND
FOLLOWING SHOWERS OVER LAKE SUPERIOR. THE LATEST THINKING IS THAT
WITH 850MB WINDS BECOMING LIGHT AROUND 18Z...AND THEN PUSHING OUT OF
THE SW THROUGH LATE AFTERNOON...THAT SNOW MAY MOVE BACK TOWARD
ONTONAGON AND N HOUGHTON COUNTIES BY LATE AFTERNOON. WITH CONTINUED
LIGHT LAKE EFFECT SNOW SHOWERS...THE ADVISORY FOR MARQUETTE COUNTY
WILL BE ALLOWED TO EXPIRE AT 18Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 546 AM EST MON DEC 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM NW ONTARIO INTO THE SRN PLAINS. THE SHORTWAVE TROUGH THAT
BROUGHT HEAVY SNOW TO THE UPPER MS VALLEY SUNDAY HAS
SHEARED/WEAKENED AND LIFTED QUICKLY TO THE EAST OF UPPER MICHIGAN.
CYCLONIC NNE LOW LEVEL FLOW COMBINED WITH ABUNDANT 850-700 MB
MOISTURE AND 850 MB TEMPS TO ARUOND -11C SUPPORTED LAKE EFFECT SNOW
INTO N CNTRL UPPER MI. 850-700 MB FGEN AHEAD OF AN 850-700 MB
THERMAL TROUGH INTO NRN MN ALSO SUPPORTED SOME LIGHT SNOW OVER NE MN
AND HELPED ENHANCE THE LES INTO FAR NW WI. SO FAR...LAND BREEZE AND
LAKE INDUCED TROUGHING HAS KEPT THE MAIN LES BANDS WEST OF IWD
THROUGH 10Z.
MAIN FCST CONCERNS ARE LES TRENDS AND SNOW AMOUNTS.
TODAY...
SATELLITE TRENDS AND MODELS SUGGEST THAT ANY LINGERING
SYNOPTIC SCALE LIFT WILL DEPART EARLY TODAY WITH THE 850-700 MB
MOISUTRE ALSO THINNING OUT BY THIS AFTERNOON ALONG WITH ONLY A
GRADUAL BACKING TREND IN THE LOW LEVEL WIND FROM NE TO NORTH. THIS
SHOULD KEEP THE LES GOING INTO NORTH CENTRAL MICHIGAN GOING THIS
MORNING WITH LIGHT TO MODERATE SNOWFALL RATES...ESPECIALLY INTO
UPSLOPE FLOW LOCATIONS. THIS SHOULD PRODUCE AN ADDITIONAL 1 TO 3
INCHES OF SNOW MAINLY IN THE HIGHER TERRAIN LOCATIONS OF MARQUETTE
COUNTY FROM THE HURON MOUNTAINS TO NEGAUNEE/ISHPMEMING AND GWINN.
HIGH RES MODELS HAVE BEEN CONSISTENT IN GRADUALLY SHIFTING THE AXIS
OF LEVEL CONV AND BRINGING THE LES BANDS INTO WESTERN GOGEBIC COUNTY
BY AROUND 12Z. EVEN THOUGH THERE MAY SOME DELAY TO THE ONSET OF
HEAVIER SNOW IF THE TROUGH MOVEMENT IS SLOWER THAN EXPECTED...A
PERIOD OF MODERATE TO HEAVY SNOW VCNTY IWD COULD BRING AT LEAST 1 TO
4 INCHES OF SNOW. HOWEVER...CONFIDENCE IN THE TIMING/DURATION OF THE
HEAVIER BAND IS STILL LIMITED. AS A WEAK RIDGE BUILDS TOWARD THE AREA
THIS AFTERNOON AND WINDS/CONV WEAKENS...THE SNOW SHOULD DIMINISH OVER
BOTH THE WEST AND N CNTRL UPPER MI.
TONIGHT...
A A WEAK SHORTWAVE AND SFC TROUGH REFLECTION WILL APPROACH
THE AREA BRINGING A SHIFT TO SW TO S WINDS. THIS SHOULD PUSH ANY
REMANING LES FROM LAKE SUPERIOR OFFSHORE DURING THE EVENING. WITH
THE VERY WEAK WIND FIELDS...THERE IS THE POSSIBILITY THAT A
SHORELINE PARALLEL OR MESO-LOW BAND MAY BRUSH THE WEST UPPER MI
SHORELINE. A WEAK BAND 700-300 MB QVECTOR CONV AND ISENTROPIC LIFT
AHEAD OF THIS FEATURE MAY SUPPORT SOME LIGHT SNOW INTO WEST UPPER
MICHIGAN. HOWEVER...ONLY SLIGHT CHANCE POPS WERE MENTIONED.
INCREASING LOW LEVEL CONV SRLY FLOW OFF OF LAKE MICHIGAN MAY ALSO
BRING AN LES BAND INTO THE SE CWA LATE BUT SHOULD HOLD OFF MAINLY
UNTIL TUES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 546 AM EST MON DEC 10 2012
SURFACE RIDGE AXIS WILL BE EAST OF THE AREA BY TUESDAY MORNING. AS
NEXT UPPER TROUGH MOVES INTO WESTERN ONTARIO WITH ASSOCIATED WEAK
SURFACE LOW WINDS WILL BECOME SOUTHERLY ACROSS THE ENTIRE AREA. 85H
TEMPS WILL REMAIN LOW ENOUGH...-10 TO -12...TO SUPPORT A LAKE EFFECT
SNOW BAND OFF OF LAKE MICHIGAN INTO THE EASTERN U.P. WINDS WILL
SLOWLY BUT STEADILY VEER THROUGH THE DAY ALLOWING THE BAND TO BE
TRANSIENT FROM WEST TO EAST WHICH SHOULD LIMIT SNOWFALL AMOUNTS OVER
EASTERN SCHOOLCRAFT AND LUCE COUNTIES IN THE 1 TO AS MUCH AS 3 INCH
RANGE.
AS SURFACE LOW MOVES ACROSS ONTARIO...SURFACE TROUGH WILL CROSS LAKE
SUPERIOR ALLOWING WINDS TO BECOME WESTERLY AND 85H TEMPS TO FALL TO
-14 BRIEFLY OVER WESTERN LAKE SUPERIOR. EXPECT SOME LAKE EFFECT SNOW
TO AFFECT THE KEWEENAW PENINSULA TUE EVENING/TUE NIGHT BEFORE WARM
ADVECTION REGIME SETS IN ACROSS THE WESTERN LAKE.
SOUTHERLY WINDS WILL RETURN FOR WEDNESDAY INTO THURSDAY AS ANOTHER
WEAK DISTURBANCE SKIRTS BY JUST NORTH OF THE AREA. ANY FORCING FOR
PRECIPITATION SHOULD REMAIN OVER NORTHERN LAKE SUPERIOR INTO
ONTARIO. 85H TEMPS FOR WEDNESDAY AND THURSDAY WILL BE IN THE 0 TO -4
RANGE RESULTING IN DAYTIME TEMPERATURES A FEW DEGREES ABOVE NORMAL.
VERY LITTLE CONFIDENCE IN THE FORECAST BEYOND THURSDAY WITH MEDIUM
RANGE MODELS SHOWING LARGE SCALE DISCREPANCIES. ECMWF HAS BEEN
CONSISTENT IN HINTING AT A POTENTIAL STORM SYSTEM DEVELOPING OVER
THE PLAINS AND LIFTING INTO THE GREAT LAKES OVER THE WEEKEND WITH
THE GFS SHOWING HIGH PRESSURE OVER THE GREAT LAKES NEXT WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 702 AM EST MON DEC 10 2012
EXPECT PREDOMINANT MVFR CONDITIONS TO DOMINATE THIS FCST PERIOD AT
ALL 3 TAF SITES WITH LINGERING LOW LEVEL MOISTURE SLOWLY WEAKENING
CYCLONIC NNE FLOW UNDER SUBSIDENCE LEFT IN THE WAKE OF DEPARTING
DISTURBANCE. THE MAJOR EXCEPTION WILL BE A PERIOD OF IFR CONDITIONS
THIS MORNING UNDER SOME HEAVIER LK EFFECT SHSN THAT WILL IMPACT IWD
AND SAW...LOCATIONS FAVORED BY THE EXPECTED NNE WIND. CONDITIONS MAY
IMPROVE TO VFR THIS EVENING AS WINDS BECOME SRLY AHEAD OF A WEAK
TROUGH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 546 AM EST MON DEC 10 2012
NORTHERLY WINDS OF 20 TO 30 KNOTS EARLY TODAY ARE EXPECTED TO
DIMINISH AS A TROUGH TO THE SOUTH OF UPPER MICHIGAN GRADUALLY
WEAKENS AND SHIFTS TO THE SOUTHEAST. BEHIND THIS FEATURE...A SERIES
OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST
OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ005.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
310 PM EST MON DEC 10 2012
.SYNOPSIS...
A STRONG COLD FRONT DEPARTS TO THE EAST THROUGH THE NIGHT. HIGH
PRESSURE BUILDS MID WEEK AND LINGERS INTO FRIDAY. NEXT
PRECIPITATION MAKER LONG ABOUT SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH TUESDAY/...
SURFACE COLD FRONT IS CURRENTLY CROSSING OHIO RIVER...PER OBS AND
RADAR. THE ENHANCED PRECIP BEHIND THE FRONT APPEARS TIED TO THE 925
MB FRONT. BECAUSE OF THIS ENHANCEMENT BEHIND THE SURFACE FRONT DID
DRAW HIGHER POPS A LITTLE FARTHER WEST THAN PREVIOUS FORECAST.
PRECIP OUT AHEAD OF THE FRONT HAS BEEN FAIRLY LIGHT...WITH LIGHT
RAIN OR EVEN JUST SOME MIST/SPRINKLES BEING REPORTED BY ASOS/S
ACROSS THE FORECAST AREA. HAVE SEEN SOME LIGHTNING JUST WEST AND
NORTH OF OUR CWA...AGAIN IT SEEMS TIED MOST CLOSELY TO THE 925 FRONT
AND UPPER LEVEL ENHANCEMENT PROVIDED BY A VORT MAX RIDING UP THE
FRONT. THAT VORT MAX HAS MOVED OFF THE NORTHEAST AND HAVE NOT SEEN
ANY LIGHTNING FOR ABOUT AN HOUR...HOWEVER RAP SHOWING ANOTHER VORT
MAX SHOULD RIDE NE ALONG THE FRONT THIS AFTERNOON...SO TRIED TO TIE
SOME SLIGHT CHANCE THUNDER TO THE 925 FRONT AND 500MB VORT MAX
COMBINATION. REALLY SHOULD NOT BE MORE THAN SOME RANDOM STRIKES
THROUGH THE AFTERNOON. MOST LOCATIONS ACROSS WV AT OR NEAR THEIR
HIGH FOR THE DAY...WITH FALLING TEMPERATURES ALREADY SHOWING UP
BEHIND THE FRONT IN SE OHIO. EXPECT A QUICK 5-10 DEGREE DROP IN THE
HOUR TO TWO AFTER THE FRONT PASSES...WITH A SLOWER COOLING TREND
AFTER THAT INTO TONIGHT. LAV GUIDANCE SEEMED FAIRLY CLOSE TO CURRENT
TRENDS...SO USED THAT AS A STARTING POINT FOR TODAYS NON-DIURNAL
CURVE.
PRECIPITATION WILL SLOWLY COME TO AN END OVERNIGHT FROM WEST TO EAST
AS THE SYSTEM MOVES EAST AND HIGH PRESSURE BEGINS TO BUILD TO THE
WEST. AS COOLER TEMPERATURES ALOFT MOVE IN...WILL SEE A TRANSITION
FROM RAIN TO SNOW JUST AS THE PRECIP IS MOVING OUT. SHOULD NOT SEE
ANY ACCUMULATIONS IN THE LOWLANDS...WITH GENERALLY 2 INCHES OR LESS
AT THE HIGHEST ELEVATIONS IN THE WV MOUNTAINS.
TOMORROW WILL FEEL CHILLY COMPARED TO WHAT WE HAVE SEEN IN DECEMBER
SO FAR...BUT IN REALITY WE WILL ONLY BE 5-7 DEGREES BELOW NORMAL
WITH HIGHS IN THE UPPER 30S AND LOWER 40S ACROSS THE LOWLANDS...AND
MID TO UPPER 30S IN THE MOUNTAINS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
SHOULD SEE MOST AREAS CLR TUESDAY NIGHT. THERE MAY BE SOME HIGH CLDS
ACROSS THE MTNS FROM UPR TROF. WITH THIS IN MIND...TRIED TO PLAY
MORE A RADIATIONAL COOLING SCENARIO HITTING THE TYPICAL COLD SPOTS
HARD. HAVE LOWS GENERALLY IN THE LOW TO MID 20S...WITH SOME TEENS IN
THE N MTN VALLEYS.
UPR TROF AXIS SHIFTS E ON WEDNESDAY. HOWEVER...LLVL THERMAL TROF
HANGS AROUND WITH ONLY A SLIGHT IMPROVEMENT IN TEMPS DESPITE
SUNSHINE.
ANOTHER COLD NIGHT WEDNESDAY NIGHT WITH READINGS SIMILAR OR A TICK
LWR THAN TUESDAY NIGHT.
UPR RIDGING BUILDS INTO AREA ON THURSDAY WITH LLVL FLOW TURNING SW.
THIS SHOULD ALLOW FOR A MORE MARKED REBOUND OF TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
TRIED TO KEEP MOUNTAIN VALLEYS COLDER THAN HPC GUIDANCE FOR THURSDAY
NIGHT...FIGURING WARMING MAINLY ALOFT AND STILL LIGHT WINDS...TO
ALLOW INVERSION TO SET UP.
ANOTHER NICE DECEMBER DAY EXPECTED ON FRIDAY. PROBABLY THE WARMEST
AFTERNOON TEMPERATURES OF THIS EXTENDED PERIOD.
WAS A BIT SLOWER INCREASING POPS SATURDAY AFTERNOON AND
EVENING...BUT AGAIN LOOKS TO BE RAIN. WILL INCREASE POPS TO LIKELY
FOR OVERNIGHT SATURDAY NIGHT.
HARD TO DETERMINE HOW LONG THE DEEP MOISTURE HOLDS IN ON SUNDAY.
BUT SOME COLDER AIR FINALLY LEAKS IN AGAIN SUNDAY NIGHT...DO MENTION
SOME SNOW SHOWERS SUNDAY NIGHT IN THE MOUNTAINS.
AS IS A FREQUENT PROBLEM IN WINTER...DAY 7 CONFIDENCE IS LOW...BUT
DID STAY A BIT COLDER THAN GUIDANCE...FIGURING ON 850 TEMPS STILL
NEAR OR SLIGHTLY BELOW ZERO CELSIUS.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
COLD FRONT WILL MOVE ACROSS THE CWA THIS AFTERNOON INTO TONIGHT.
CURRENTLY ITS RUNNING FROM KPKB TO KHTS. WILL SEE S/SW WINDS SHIFT
TO NW AS THE FRONT PASSES...WITH SOME GUSTS UP TO ABOUT 20KTS
EXPECTED. SEEING SOME ENHANCED PRECIP BEHIND THE FRONT...OR ACTUALLY
IN LINE WITH THE FRONT AT 925MB. WILL SEE LIGHT RAIN CONTINUE AHEAD
OF THE FRONT...WITH HEAVIER MVFR SHOWERS ALONG AND BEHIND THE FRONT.
WILL ALSO SEE IFR CEILINGS MOVE IN ALONG AND BEHIND THE
FRONT...GRADUALLY IMPROVING BACK TO MVFR THEN VFR TOMORROW. DID HAVE
SOME LIGHTNING TIED TO A VORT MAX RIDING UP THE 925 FRONT
EARLIER...AND RAP SHOWING ANOTHER VORT MAX SHOULD MOVE THROUGH THIS
AFTERNOON...SO CONTINUED THE IDEA OF SOME VCTS/CB THIS AFTERNOON
WITH THAT FEATURE. WITH THAT SAID...THUNDER SHOULD BE FAIRLY RANDOM
AND ISOLATED...SO WAS ON THE FENCE TO EVEN INCLUDE IT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF RESTRICTIONS IN SHOWERS COULD VARY.
VCTS/CB MAY NOT MATERIALIZE THIS AFTERNOON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H H H H H H M M H H H
HTS CONSISTENCY H M H H H H H H H H H H
BKW CONSISTENCY M M M H H H H H H H H H
EKN CONSISTENCY M L M H H H M M M M M L
PKB CONSISTENCY M M M H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z TUESDAY...
NONE.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...MZ/26
NEAR TERM...MZ
SHORT TERM...30
LONG TERM...KTB
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1250 PM EST MON DEC 10 2012
.SYNOPSIS...
A STRONG COLD FRONT DEPARTS TO THE EAST THROUGH THE NIGHT. HIGH PRESSURE
BUILDS MID WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
SURFACE COLD FRONT IS CURRENTLY CROSSING OHIO RIVER...PER OBS AND
RADAR. THE ENHANCED PRECIP BEHIND THE FRONT APPEARS TIED TO THE 925
MB FRONT. BECAUSE OF THIS ENHANCEMENT BEHIND THE SURFACE FRONT DID
DRAW HIGHER POPS A LITTLE FARTHER WEST THAN PREVIOUS FORECAST.
PRECIP OUT AHEAD OF THE FRONT HAS BEEN FAIRLY LIGHT...WITH LIGHT
RAIN OR EVEN JUST SOME MIST/SPRINKLES BEING REPORTED BY ASOS/S
ACROSS THE FORECAST AREA. HAVE SEEN SOME LIGHTNING JUST WEST AND
NORTH OF OUR CWA...AGAIN IT SEEMS TIED MOST CLOSELY TO THE 925 FRONT
AND UPPER LEVEL ENHANCEMENT PROVIDED BY A VORT MAX RIDING UP THE
FRONT. THAT VORT MAX HAS MOVED OFF THE NORTHEAST AND HAVE NOT SEEN
ANY LIGHTNING FOR ABOUT AN HOUR...HOWEVER RAP SHOWING ANOTHER VORT
MAX SHOULD RIDE NE ALONG THE FRONT THIS AFTERNOON...SO TRIED TO TIE
SOME SLIGHT CHANCE THUNDER TO THE 925 FRONT AND 500MB VORT MAX
COMBINATION. REALLY SHOULD NOT BE MORE THAN SOME RANDOM STRIKES
THROUGH THE AFTERNOON. MOST LOCATIONS ACROSS WV AT OR NEAR THEIR
HIGH FOR THE DAY...WITH FALLING TEMPERATURES ALREADY SHOWING UP
BEHIND THE FRONT IN SE OHIO. EXPECT A QUICK 5-10 DEGREE DROP IN THE
HOUR TO TWO AFTER THE FRONT PASSES...WITH A SLOWER COOLING TREND
AFTER THAT INTO TONIGHT. LAV GUIDANCE SEEMED FAIRLY CLOSE TO CURRENT
TRENDS...SO USED THAT AS A STARTING POINT FOR TODAYS NON-DIURNAL
CURVE.
PRECIPITATION WILL SLOWLY COME TO AN END OVERNIGHT FROM WEST TO EAST
AS THE SYSTEM MOVES EAST AND HIGH PRESSURE BEGINS TO BUILD TO THE
WEST. AS COOLER TEMPERATURES ALOFT MOVE IN...WILL SEE A TRANSITION
FROM RAIN TO SNOW JUST AS THE PRECIP IS MOVING OUT. SHOULD NOT SEE
ANY ACCUMULATIONS IN THE LOWLANDS...WITH GENERALLY 2 INCHES OR LESS
AT THE HIGHEST ELEVATIONS IN THE WV MOUNTAINS.
TOMORROW WILL FEEL CHILLY COMPARED TO WHAT WE HAVE SEEN IN DECEMBER
SO FAR...BUT IN REALITY WE WILL ONLY BE 5-7 DEGREES BELOW NORMAL
WITH HIGHS IN THE UPPER 30S AND LOWER 40S ACROSS THE LOWLANDS...AND
MID TO UPPER 30S IN THE MOUNTAINS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
LOW LEVEL MOISTURE ERODES THROUGH THE DAY TUESDAY...WITH THE LAST OF
THE UPSLOPE POPS DISINTEGRATING WITHIN THE FIRST 6 HOURS. EXPECT
FAIRLY RAPID CLEARING WITH STRONG RADIATIONAL COOLING TUESDAY NIGHT
UNDER A CLEAR SKY...CALM WIND...AND LOW DEWPOINTS. HIGH PRESSURE TO
DOMINATE THROUGH MID WEEK WITH SLOW RECOVERY TO THE TEMPERATURES IN
THE COLDER AIRMASS. UPPER TROUGH AXIS TO PASS WEDNESDAY WITH LITTLE
FANFARE...AND ONLY ACKNOWLEDGE THIS WITH A MODEST CLOUD COVER BUMP
OVER THE FAR NORTHERN ZONES.
OPTED FOR THE LOWER SIDE OF GUIDANCE IN DEWPOINTS AND TEMPERATURES
IN THE COLDER AIRMASS BEYOND TUESDAY. THIS IS ESPECIALLY TRUE FOR
THE OVERNIGHT PERIODS TUESDAY AND WEDNESDAY WHERE VALUES WERE MORE
AGGRESSIVELY DROPPED.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
SFC HIGH PRESSURE CENTER PROGGED TO BE LOCATED TO THE EAST OF AREA
OVER THE MID-ATLANTIC SEABOARD THURSDAY AND FRIDAY WITH
SOUTH/SOUTHWESTERLY FLOW IN PLACE. AS SUCH...A WARMING TREND UNDER
MOSTLY SUNNY SKIES WILL BEGIN AFTER A RELATIVELY COOL TUE AND
WED...WITH MAX TEMPS THU INTO THE LOWER 50S LOWLANDS AND INTO THE
MID AND UPPER 50S BY FRIDAY. BY SATURDAY EXTENDED OPERATIONAL NWP
BEGINS TO DIVERGE ON THE HANDLING OF A SYSTEM PROGGED TO EJECT OUT
OF THE ROCKIES. THE ECMWF TAKES A MORE NORTHEASTERLY TRACK TOWARDS
THE UPPER MIDWEST AND BECOMES CLOSED IN THE PROCESS...WHILE THE GFS
REMAINS OPEN AT UPPER LEVELS AND IS MORE EASTERLY IN ITS COURSE AND
MORE PROGRESSIVE. IN SHORT...THE EURO KEEPS THE FORECAST AREA DRY
SATURDAY WITH FEWER CLOUDS WHILE THE GFS IS MUCH MORE CLOUDY AND
BRINGS IN PRECIP BY AT LEAST MIDDAY SATURDAY. VARIOUS ENSEMBLES SEEM
TO AT LEAST LOOSELY SUPPORT THE EURO SOLUTION AND THUS WILL LEAN THE
FORECAST IN THAT DIRECTION. HAVE CODED MAINLY UPPER 50S LOWLANDS
FOR SATURDAY...BUT WITH 925MB TEMPS AROUND 9-10C IF THE EURO SOLUTION
FULLY PANS OUT TEMPS WOULD LIKELY CLIMB INTO THE LOWER 60S. HAVE
ALSO INCLUDED A SLIGHT CHANCE OF RAIN SHOWERS FOR SATURDAY TO
ACCOUNT FOR UNCERTAINTY IN THE GFS TRACK BUT LEANED THE HIGHER LOW/MID
CHANCE POPS BEGINNING SATURDAY NIGHT AND SUNDAY.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
COLD FRONT WILL MOVE ACROSS THE CWA THIS AFTERNOON INTO TONIGHT.
CURRENTLY ITS RUNNING FROM KPKB TO KHTS. WILL SEE S/SW WINDS SHIFT
TO NW AS THE FRONT PASSES...WITH SOME GUSTS UP TO ABOUT 20KTS
EXPECTED. SEEING SOME ENHANCED PRECIP BEHIND THE FRONT...OR ACTUALLY
IN LINE WITH THE FRONT AT 925MB. WILL SEE LIGHT RAIN CONTINUE AHEAD
OF THE FRONT...WITH HEAVIER MVFR SHOWERS ALONG AND BEHIND THE FRONT.
WILL ALSO SEE IFR CEILINGS MOVE IN ALONG AND BEHIND THE
FRONT...GRADUALLY IMPROVING BACK TO MVFR THEN VFR TOMORROW. DID HAVE
SOME LIGHTNING TIED TO A VORT MAX RIDING UP THE 925 FRONT
EARLIER...AND RAP SHOWING ANOTHER VORT MAX SHOULD MOVE THROUGH THIS
AFTERNOON...SO CONTINUED THE IDEA OF SOME VCTS/CB THIS AFTERNOON
WITH THAT FEATURE. WITH THAT SAID...THUNDER SHOULD BE FAIRLY RANDOM
AND ISOLATED...SO WAS ON THE FENCE TO EVEN INCLUDE IT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF RESTRICTIONS IN SHOWERS COULD VARY.
VCTS/CB MAY NOT MATERIALIZE THIS AFTERNOON.
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 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY H H H H H M H H H H H H
HTS CONSISTENCY H H H H H M M H H H H H
BKW CONSISTENCY H M H H M H H M H H H H
EKN CONSISTENCY H H H H H H H M H H H H
PKB CONSISTENCY H H H H H M M H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z TUESDAY...
NONE.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...MZ/26
NEAR TERM...MZ
SHORT TERM...26
LONG TERM...50
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
533 PM EST MON DEC 10 2012
.SYNOPSIS...
A COLD FRONT WILL TRAVERSE THE REGION LATE TODAY AND TONIGHT. WET
WEATHER WILL CONTINUE INTO THIS EVENING...THEN COLDER AND DRIER
CONDITIONS MOVE IN FOR THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LIGHT RAIN AND DRIZZLE AHEAD OF APPROACHING COLD FRONT WILL
CONTINUE THROUGH THE AFTERNOON AND INTO THIS EVENING. SHARP YET
SLOW MOVING COLD FRONT FOR LATE AFTERNOON/EVENING WILL BRING A
WIND SHIFT TO THE WEST AND A FEW HOURS AFTER THAT PRECIP SHOULD
SHUT DOWN FOR MOST LOCATIONS /ABOUT 03-06Z/. EXCEPTION WILL BE
HIGHER TERRAIN OF THE WEST...WHERE PRECIP WILL LINGER AS SNOW
SHOWERS TONIGHT - LIKELY PRODUCING A COATING OF SNOW. COLDER AIR
EVENTUALLY WORKS IN OVERNIGHT...IMPACTING NW MTNS FIRST...BUT WILL
TAKE A GOOD PORTION OF THE OVERNIGHT TO REACH THE LOWER SUSQ. AIR
STILL NOT FORMIDABLE FOR DECEMBER THOUGH...AS THESE READINGS
REMAIN WELL ABOVE NORMAL FOR THIS TIME OF YEAR.
HIGH PRESSURE BEGINS TO BUILD IN LATE TONIGHT INTO TUE AS
CONDITIONS IMPROVE BACK TO VFR BY TUES MORNING FOR MOST...POSS TUE
AFT IN THE HIGHER TERRAIN.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE NOSES IN PRETTY QUICKLY TUESDAY SHUTTING DOWN
WHATEVER SNOW SHOWERS THAT ARE ONGOING IN THE WEST...AND BEGINNING
A PROLONGED PERIOD OF RATHER BRIGHT AND FAIR WEATHER.
HIGHS IN THE 30S AND 40S WILL AVERAGE A FEW DEG EITHER SIDE OF
NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
ALL MODEL GUIDANCE SHOWS A LARGE AREA OF HIGH PRESSURE DOMINATING
THE REGIONAL WEATHER PATTERN THROUGH FRIDAY...SUPPORTING A HIGH
CONFIDENCE FCST OF FAIR WEATHER AND LGT WINDS. WITH THE BENEFIT OF
MSUNNY SKIES...DAYTIME HIGHS SHOULD REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HOWEVER...OVERNIGHT LOWS SHOULD BE NEAR DECEMBER NORMS DUE
TO THE CLEAR SKIES/CALM WIND.
LOW PRESSURE WILL EJECT NEWD FROM THE S/CNTRL PLAINS THEN AFFECT
THE CNTRL-ERN STATES INTO THE WEEKEND. SOME WINTRY PCPN IS PSBL ON
THE NRN SIDE OF THE MSTR SHIELD ASSOC WITH THIS SYSTEM. THERE IS
STILL A HIGH LEVEL OF UNCERTAINTY IN STORM TRACK AND EXACT
LOCATION OF THE RAIN/SNOW LINE...BUT CURRENTLY EXPECT ANY WINTRY
WEATHER TO BE CONFINED TO SOME PORTION OF AN AREA COVERING THE
GRTLKS INTO THE NORTHEAST STATES. STAY TUNED FOR MORE DETAILS ON
POTENTIAL FOR WINTRY WEATHER THIS WEEKEND.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
22Z SFC ANALYSIS SHOWS A COLD FRONT BISECTING PA...RUNNING FROM
ELM SOUTHWARD THRU UNV AND JST. SHIFTING WINDS TO THE NW BEHIND
THE FRONT WILL CAUSE LINGERING MOISTURE TO ASCEND THE ALLEGHENIES...CAUSING
CONTINUED -SRHA AND IFR CIGS AT JST. LATEST RUC SOUNDINGS SUGGEST
A CHANGEOVER TO SNOW AT BFD BY ARND 23Z...WITH A FEW HRS OF IFR
CIGS/VSBYS LIKELY THERE THIS EVENING.
FURTHER EAST...LOW LVL STABLE AIR MASS PERSISTS ACROSS THE SUSQ
VALLEY...WHERE LOW CIGS/FOG ARE REPORTED AT 22Z. HOWEVER...PASSAGE OF
COLD FRONT /ARND 00Z AT IPT AND 02Z-03Z AT MDT AND LNS/ WILL BRING
A WSHIFT TO THE NW WITH RAPIDLY IMPROVING CONDS.
LINGERING MVFR CIGS AND SCT -SHSN MAY PERSIST FROM MIDNIGHT THRU
MIDDAY TUE AT BFD/JST...WHILE DOWNSLOPING NW FLOW LIKELY BRINGS A
RETURN TO VFR CONDS EAST OF THE MTNS.
HIGH PRESSURE WILL BUILD INTO THE REGION BY TUE AFTN...LIKELY
CAUSING ANY LINGERING MVFR STRATOCU TO BREAK UP OVR THE W MTNS.
OUTLOOK...
WED-FRI...MAINLY VFR.
SAT...MVFR POSS IN RAIN SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/RXR
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
344 PM CST MON DEC 10 2012
.DISCUSSION...
LOW AND MIDLEVEL CLOUDS WERE RAPIDLY DISSIPATING ACROSS THE
MIDSOUTH. NORTHWEST SURFACE WINDS PREVAILED...AROUND THE EASTERN
PERIPHERY OF AN ARCTIC SURFACE PRESSURE RIDGE CENTERED OVER
OKLAHOMA. THIS PRESSURE RIDGE WILL LIFT INTO THE LOWER MS AND OHIO
RIVER VALLEYS ON TUESDAY...PROVIDING LIGHT WINDS AND PRIME
NOCTURNAL RADITIONAL COOLING CONDITIONS THROUGH THURSDAY.
THE LATTER HALF OF THE WEEK WILL SEE LOW LEVEL SOUTHERLY FLOW
RETURN UNDER RIDGING ALOFT. BEST FEED OF GULF MOISTURE WILL REMAIN
OVER TX AND THE SOUTHERN PLAINS ON FRIDAY. THIS LOW LEVEL MOISTURE
AXIS WILLS SHIFT EASTWARD INTO THE MIDSOUTH... AHEAD OF A COMPACT
CLOSED UPPER LOW LIFTING INTO THE MID MS RIVER VALLEY. A TRAILING
COLD FRONT AND MIDLEVEL TROF AXIS WILL PROVIDE A CHANCE OF RAIN
OVER THE MIDSOUTH ON SATURDAY.
THE ECMWF HAS BEEN CONSISTENT IN BRINGING A DEEPER CLOSED LOW
ACROSS THE SOUTHERN PLAINS NEXT MONDAY...AND INTO THE MIDSOUTH ON
TUESDAY. GIVEN THE MUCH GREATER RUN TO RUN CONSISTENCY COMPARED TO
THE GFS...HAVE BASED DAYS 7 AND 8 ON THE ECMWF MODEL.
PWB
&&
.AVIATION...
18Z TAF CYCLE
CIGS ARE LIFTING AS A DRY SLOT MOVES IN FROM THE WEST. HOWEVER...THERE
ARE AN ABUNDANCE OF LOW CLOUDS OVER MISSOURI THAT WILL BEGIN TO
ROTATE INTO THE CWA AFTER 22-23Z. THE RUC KEEPS LOW CLOUDS OVER
THE AREA FOR MUCH OF THE OVERNIGHT PERIOD WITH POSSIBLE CLEARING
BEGINNING AFTER MIDNIGHT ACROSS NE ARKANSAS. THE NAM HAS DRY AIR
FILTERING IN DUE TO THE HIGH PRESSURE BUILDING INTO THE REGION AND
ESSENTIALLY ERODES THE LOW CLOUDS. THUS VFR CONDITIONS WOULD
PREVAIL IF THE NAM IS CORRECT. TOUGH FORECAST AND WITH THIS PACKAGE WILL
LEAN TOWARD THE RUC BUT NOT VERY CONFIDENT. NORTHWEST WINDS OF
10-15 KTS WITH HIGHER GUSTS WILL BEGIN TO DIE DOWN THIS AFTERNOON.
AFTER 00Z...NORTHERLY WINDS AROUND 5 KTS CAN BE EXPECTED.
KRM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 25 44 28 51 / 0 0 0 0
MKL 22 43 21 50 / 0 0 0 0
JBR 22 43 23 50 / 0 0 0 0
TUP 24 48 26 52 / 0 0 0 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1119 AM CST MON DEC 10 2012
.UPDATE... /ISSUED 921 AM CST MON DEC 10 2012/
MIDMORNING UPDATE SENT FOR ADJUSTMENTS TO HOURLY TEMPERATURE
TRENDS AND PRECIP TYPE/CHANCES. A FEW FLURRIES CANNOT BE RULED OUT
OVER NORTHEAST AR...INTO NORTHWEST TN. HOWEVER... WITH DRY
UNDERCUTTING CLOUD BASES AROUND 10KFT... AND MIDLEVEL LIFT EXITING
THE AREA...HAVE PULLED MENTION OF LIGHT WINTRY PRECIP.
OTHER ADJUSTMENTS WERE MADE TO SKY CONDITION... BASED ON 14Z RUC
DELAYED EXIT OF THE LOW CLOUDS. GOES VISIBLE IMAGERY SHOWED A
SOLID 2KFT TO 3KFT LAYER OVER ALL BUT THE NORTHWEST TIP OF MO.
THIS MAY BE SLOWER TO ERODE THAN WHAT THE 12Z NAM SUGGESTS.
PWB
&&
.DISCUSSION... /ISSUED 329 AM CST MON DEC 10 2012/
WEATHER IS RAPIDLY CHANGING ACROSS THE MIDSOUTH. THUNDERSTORMS ARE
EXITING EAST INTO CENTRAL TENNESSEE AND ALABAMA WITH A DRASTICALLY
COLDER AIRMASS APPROACHING EAST ARKANSAS. 3 AM TEMPERATURES RANGE
FROM 63 DEGREES IN NORTHEAST MISSISSIPPI...TO 45 DEGREES IN
NORTHEAST ARKANSAS. HOWEVER FURTHER WEST IN NORTH CENTRAL
ARKANSAS..TEMPERATURES ARE BELOW FREEZING. THIS COLD AIRMASS WILL
MOVE INTO THE MIDSOUTH BY SUNRISE. SOME LOCATIONS ESPECIALLY EAST
OF THE MISSISSIPPI RIVER WILL LIKELY SEE THE WARMEST TEMPERATURES
OF THE DAY BEFORE OR AROUND SUNRISE WITH STEADY OR FALLING
TEMPERATURES DURING THE DAY.
THE NAM REMAINS THE LONE OUTLIER AMONG GUIDANCE BRINGING IN UP TO
AN INCH OF ACCUMULATING SNOWFALL EARLY THIS MORNING THROUGH MIDDAY
TODAY. NO OTHER DATA SOURCE I WAS ABLE TO FIND HINTED AT ANYTHING
MORE THAN TRACE AMOUNTS OF FREEZING OR FROZEN PRECIPITATION. SNOW
HAS DEVELOPED AND IS REACHING THE GROUND IN SOUTH CENTRAL
OKLAHOMA WHERE DEW POINTS ARE IN THE MIDDLE TO UPPER 20S. HOWEVER
FARTHER EAST IN EAST OKLAHOMA WHERE DEW POINTS ARE IN THE
TEENS...NO OBSERVATIONS INDICATE SNOW IS REACHING THE GROUND.
DECIDED TO ONLY MENTION A WINTRY MIX IN NORTHEAST ARKANSAS AND THE
MISSOURI BOOTHEEL FOR A FEW HOURS THIS MORNING BEFORE THE DRY
AIR MOVES IN BRINGING AN END TO ANY CHANCE OF PRECIP.
BEYOND THE CHANCE OF OUR FIRST WINTRY PRECIPITATION THIS
YEAR...COLD TEMPERATURES WILL BE THE MAIN STORM EARLY THIS WEEK.
WINTER HAS ARRIVED. HIGHS TOMORROW WILL LIKELY REMAIN IN THE 40S
AREA WIDE WITH THE COLDEST LOCATIONS STRUGGLING TO WARM OUT OF THE
LOW 40S. MORNING LOWS TOMORROW MORNING WILL BE IN THE LOW TO
MIDDLE 20S ACROSS MOST OF THE AREA. SKIES WILL BE MOSTLY CLEAR
TUESDAY THROUGH THE END OF THE WORK WEEK WITH DRY CONDITIONS.
TEMPERATURES WILL TREND A FEW DEGREES WARMER EACH DAY WITH HIGHS
APPROACHING THE 60 DEGREE MARK BY FRIDAY.
NEXT WEEKEND...GUIDANCE POINTS TO RAIN RETURNING TO THE MIDSOUTH.
ANOTHER COLD FRONT LOOKS LIKELY LATE SATURDAY OR SUNDAY.
&&
.AVIATION...
18Z TAF CYCLE
CIGS ARE LIFTING AS A DRY SLOT MOVES IN FROM THE WEST. HOWEVER...THERE
ARE AN ABUNDANCE OF LOW CLOUDS OVER MISSOURI THAT WILL BEGIN TO
ROTATE INTO THE CWA AFTER 22-23Z. THE RUC KEEPS LOW CLOUDS OVER
THE AREA FOR MUCH OF THE OVERNIGHT PERIOD WITH POSSIBLE CLEARING
BEGINNING AFTER MIDNIGHT ACROSS NE ARKANSAS. THE NAM HAS DRY AIR
FILTERING IN DUE TO THE HIGH PRESSURE BUILDING INTO THE REGION AND
ESSENTIALLY ERODES THE LOW CLOUDS. THUS VFR CONDITIONS WOULD
PREVAIL IF THE NAM IS CORRECT. TOUGH FORECAST AND WITH THIS PACKAGE WILL
LEAN TOWARD THE RUC BUT NOT VERY CONFIDENT. NORTHWEST WINDS OF
10-15 KTS WITH HIGHER GUSTS WILL BEGIN TO DIE DOWN THIS AFTERNOON.
AFTER 00Z...NORTHERLY WINDS AROUND 5 KTS CAN BE EXPECTED.
KRM
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 46 28 44 29 / 10 0 0 0
MKL 46 23 44 23 / 10 0 0 0
JBR 37 23 42 24 / 10 0 0 0
TUP 53 27 47 29 / 20 0 0 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1120 AM CST MON DEC 10 2012
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...CEILING BEGINNING TO ERODE OVER THE NORTHWESTERN HALF
OF THE CWA...IMPROVING IN THE MIDDLE VALLEY TO BROKEN AT ABOUT
3500 FT AS WELL. EXPECT THE HIGH MVFR TO HOLD ON FOR A FEW MORE
HOURS IN THE LOWER VALLEY AND NEAR THE COAST. NORTH WINDS WILL
REMAIN STRONG WITH GUSTS IN THE 25 TO 30 KNOT RANGE EXPECTED
THROUGH THE REMAINDER OF THE AFTERNOON...ONLY SLACKENING A BIT
AFTER ABOUT 3 PM.
TONIGHT EXPECT WINDS TO SUBSIDE FAIRLY QUICKLY AND SHIFT MORE
NORTHEASTERLY WITH CIG/VISBY BECOMING VFR...MID CLOUD DECK
POSSIBLE AT AROUND 5000 FT. WINDS SHOULD REMAIN LIGHT OVERNIGHT
PICKING UP TO ABOUT 10 TO 15 KNOTS BY MID MORNING TOMORROW OUT OF
THE NORTH TO NORTHEAST WITH VFR EXPECTED. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 954 AM CST MON DEC 10 2012/
DISCUSSION...FRESHENED UP FORECAST PACKAGE FOLLOWING FROPA. FRONT
HAS CLEARED ALL BUT THE SOUTHEASTERNMOST MARINE ZONES. STRONG COLD
AIR ADVECTION ONGOING ACROSS THE REGION WITH TEMPS AND DEWPOINTS
DROPPING. WINDS ARE ESSENTIALLY REMAINING IN LINE WITH WIND GUSTS
OF 30 TO 35 MPH CONTINUING IN THE VALLEY...AND SLOWLY DECREASING
AS YOU MOVE NORTH. EXPECT VERY WINDY CONDITIONS TO CONTINUE RIGHT
ALONG THE COAST AND WILL CONTINUE THE WIND ADVISORY THERE. STRONG
WINDS CONTINUE TO BE REPORTED OVER THE LAGUNA AND COASTAL
WATERS...AND 12Z RAOB ANALYSIS 850MB AND LOW LEVEL COLD AIR
ADVECTION UNDERWAY EXPECT THAT WILL CONTINUE FOR AT LEAST THE NEXT
4 TO 5 HOURS BEFORE DROPPING CLOSER TO THE 20 TO 25 KNOT RANGE
LATE THIS AFTERNOON/EARLY THIS EVENING. TEMPERATURES TONIGHT LOOK
ON TRACK IN THE MID 40S SOUTH...UPPER 30S NORTH BUT THAT WILL BE A
PRIMARY FOCUS OF THE UPCOMING FORECAST PACKAGE. THE AMOUNT OF DRY
AIR WORKING IN...WITH THE MID TEENS DEWPOINTS IN WEST CENTRAL TEXAS
MAY LEAD TO A DOWNWARD ADJUSTMENT IN TONIGHTS LOWS ONCE A CLEARER
PICTURE ON CLOUD COVER DEVELOPS. FOR NOW LOW TO MID CLOUD DECK
CONTINUES JUST BEHIND THE FRONT. WITH LIGHT FRONTAL OVERRUNNING
OCCURRING FROM ABOUT 4 TO 14KFT. WITH THAT ALSO CONTINUED A SLIGHT
CHANCE FOR STRATIFORM RAIN AT TIMES...BUT WITH NO REAL REINFORCING
WAVE TO INCREASE MID AND LOWER LEVEL OMEGA DO NOT EXPECT LARGE
AREAS OR HEAVY PRECIP TO FORM THROUGH THE REST OF THE DAY AND THE
AFTERNOON...WITH MOST OF OUR MEASURABLE PRECIP PROBABLY OVER FOR
THE DAY. UPDATED PACKAGE/ZONES ALREADY OUT. /68-JGG/
PREV DISCUSSION... /ISSUED 626 AM CST MON DEC 10 2012/
DISCUSSION...AFTER GETTING A LOOK AT CONDITIONS UPSTREAM AND THE
LATEST RAP DATA MADE SLIGHT UPTICKS TO THE WIND FORECAST WHICH
NECESSITATED UPGRADING THE LAGUNA MADRE TO GALE WARNING THROUGH MID
AFTERNOON FOR FREQUENT GALE FORCE GUSTS AND HOISTING A WIND
ADVISORY FOR COASTAL AREAS THROUGH MID AFTERNOON. NO OTHER CHANGES
AT THIS TIME. /68-JGG/
PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 10 2012/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...THE LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE VFR/MVFR CONDITIONS OVER DEEP SOUTH TEXAS. CURRENTLY THE
COLD FRONT IS LOCATED FROM SOUTH OF KBKS AND KHBV TO KAPY AND WILL
MOVE ACROSS THE RIO GRANDE VALLEY AROUND 14Z. THE LIGHT WINDS HAVE
ALLOWED SOME MVFR CIGS/VIS TO DEVELOP AHEAD OF FRONT...THIS WILL
BE SHORT LIVED. SHOWERS AND ISOLATED THUNDERSTORMS ARE ALSO A
POSSIBILITY WITH BETTER CHANCES FROM KMFE EASTWARD. NORTH WINDS
WILL DEVELOP BEHIND THE FRONT AND QUICKLY INCREASING TO 20 TO 25
KT WITH GUSTS TO AROUND 30 BY MID MORNING THROUGH THE AFTERNOON.
CIGS WILL SLOWLY RAISE THROUGH THE DAY BUT SHOULD REMAIN MVFR
THROUGH MID TO LATE AFTERNOON.
PREV DISCUSSION... /ISSUED 425 AM CST MON DEC 10 2012/
SHORT TERM /TODAY THROUGH TUESDAY/...THE COLD FRONT CURRENTLY
LOCATED FROM CORPUS CHRISTI TO ALICE TO LAREDO WILL SWEEP THROUGH
DEEP SOUTH TEXAS THIS MORNING. THE LATEST SURFACE OBSERVATIONS AND
MODEL GUIDANCE INDICATES THAT THE FRONT WILL MOVE THROUGH THE AREA A
LITTLE FASTER. MADE MINOR ADJUSTMENTS TO THE TIMING OF THE FRONT...
WHICH WILL MOVE ACROSS THE NORTHERN COUNTIES IN THE NEXT TWO HOURS
AND THROUGH THE LOWER VALLEY BY MID MORNING. CURRENT BROWNSVILLE
WSR-88D SHOWS LITTLE CONVECTION ACROSS DEEP SOUTH TEXAS BUT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS ARE STILL EXPECTED THIS
MORNING. MUCH COOLER TODAY WITH HIGH TEMPERATURES ALMOST 30 DEGREES
COOLER THAN YESTERDAY. HIGH TEMPERATURES TODAY WILL OCCUR THIS
MORNING THEN TEMPERATURES WILL HOLD STEADY FOR A FEW HOURS BEFORE
DECREASING THIS AFTERNOON. BREEZY NORTH WINDS WILL OCCUR IN THE WAKE
OF THE FRONT AND CONTINUE THROUGH THE DAY. OVERNIGHT LOW
TEMPERATURES FOR TONIGHT WILL FALL INTO THE UPPER 30S OVER THE
NORTHERN AREAS AND IN THE LOWER 40S IN THE VALLEY AND ALONG THE
COAST. HIGH TEMPERATURES FOR TUESDAY WILL BE IN THE 60S.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...BENIGN CONDITIONS WILL
CONTINUE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS SURFACE HIGH
PRESSURE COMBINES WITH A VERY DRY ATMOSPHERE IN THE WAKE OF THE COLD
FRONT MENTIONED ABOVE. ISOLATED SHOWERS WILL DEVELOP THURSDAY...AND
CONTINUE THROUGH FRIDAY...AS A DEVELOPING ONSHORE FLOW PUMPS DEEPER
MOISTURE INTO DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY...AND
INTERACTS WITH A SERIES OF WEAK MID-LEVEL DISTURBANCES PASSING
OVERHEAD IN THE WEST-SOUTHWEST TO EAST-NORTHEAST 500 MB FLOW. A
BRIEF RESPITE IN THE PRECIPITATION MAY OCCUR FRIDAY NIGHT BEFORE
BEGINNING AGAIN SATURDAY...AND LASTING THROUGH SUNDAY...DUE TO THE
SLOW PASSAGE OF A WEAK COLD FRONT. BELOW NORMAL TEMPERATURES EARLY
IN THE LONG TERM PERIOD WILL QUICKLY RETURN TO ABOVE NORMAL LEVELS
DUE TO THE RE-DEVELOPING ONSHORE FLOW.
MARINE...TODAY THROUGH TUESDAY...THE COLD FRONT WILL MOVE THROUGH
THE LOWER TEXAS COASTAL WATERS LATER THIS MORNING RESULTING IN
VERY STRONG NORTH WINDS CONTINUING THROUGH THIS AFTERNOON. A GALE
WARNING IS IN EFFECT THROUGH THIS AFTERNOON FOR THE GULF WATERS
EAST OF PADRE ISLAND. SMALL ADVISORY CONDITIONS ARE LIKELY ON THE
LAGUNA MADRE THROUGH THIS AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE LOWER TEXAS COASTAL
WATERS TODAY. SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE THIS
EVENING THROUGH EARLY TUESDAY MORNING ON THE GULF WATERS. HIGH
PRESSURE SETTLES OVER THE AREA IN THE WAKE OF THE FRONT.
TUESDAY NIGHT THROUGH SUNDAY...GENERALLY MODERATE WINDS AND SEAS
ARE LARGELY EXPECTED THROUGH THE PERIOD...AS AN ONSHORE FLOW RE-
DEVELOPS AND THEN PREVAILS. SMALL CRAFT MAY NEED TO EXERCISE
CAUTION FOR THE GULF OF MEXICO WATERS EAST OF PADRE ISLAND FROM
TUESDAY NIGHT THROUGH SATURDAY. THE APPROACH AND PASSAGE OF A WEAK
COLD FRONT SATURDAY NIGHT WILL BRING A SLIGHT DECREASE IN WINDS
AND SEAS FOR THAT TIME AND THROUGH SUNDAY.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ251-256-257.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM CST THIS EVENING FOR
GMZ130-132-135.
GALE WARNING UNTIL 2 PM CST THIS AFTERNOON FOR GMZ130-132-135.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 4 AM CST TUESDAY
FOR GMZ150-155-170-175.
GALE WARNING UNTIL 6 PM CST THIS EVENING FOR GMZ150-155-170-175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/54
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
333 PM CST MON DEC 10 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
332 PM CST MON DEC 10 2012
AT 3 PM...LOW CLOUDS PERSISTED ACROSS MUCH OF THE FORECAST AREA.
THIS MOISTURE WAS TRAPPED BELOW A SUBSIDENCE INVERSION. THE
VISIBLE AND FOG PRODUCT /11-3.9 MICRON CHANNEL/ SHOW THAT THE
CLOUDS ARE STARTING TO BREAK UP IN THE DODGE CENTER...AUSTIN...
CHARLES CITY AREAS. THE RAP SEEMS TO BE HANDLING THIS THE BEST.
THEY SHOW THAT A NARROW AREA OF CLEARING WILL MOVE EAST ACROSS
NORTHEAST IOWA AND SOUTHEAST MINNESOTA THIS EVENING. THIS AREA
REMAINS NARROW DUE TO ANOTHER AREA OF CLOUDS MOVING INTO THE
REGION FROM THE DAKOTAS. THIS CLEARING WILL ALLOW A RAPID DROP IN
TEMPERATURES DUE TO FRESH SNOW AND LIGHT WINDS...AND THEN THE
TEMPERATURES WILL RISE AS THE CLOUDS MOVE BACK INTO THE AREA.
ON TUESDAY AFTERNOON AND EVENING...A SHORT WAVE TROUGH WILL MOVE
ACROSS THE AREA. AHEAD OF THIS WAVE...MODERATE 270 TO 280K
ISENTROPIC LEADS TO SATURATION UP TO 775 MB. HOWEVER AS THE WAVE
IS MOVING THROUGH THE REGION...THERE IS VERY LITTLE OMEGA AND THE
LOW LEVEL LAPSE RATES ARE NOT THAT STEEP. AS A RESULT...NOT
EXPECTING ANY ACCUMULATING SNOW. HOWEVER WOULD NOT BE TOO
SURPRISED TO SEE A FEW FLURRIES. SINCE THIS WAVE IS CURRENTLY NOT
PRODUCING ANYTHING UPSTREAM AND THE FORCING AND MOISTURE LOOKS
SIMILAR...DID NOT INCLUDE THEM IN THE FORECAST AT THIS TIME.
ON WEDNESDAY...THE 500 MB FLOW BECOMES ZONAL. THIS KEEPS THE NEXT
2 SHORT WAVE TROUGHS /WEDNESDAY AND THURSDAY/ NEAR THE
U.S./CANADIAN BORDER. BOTH OF THESE SYSTEMS WILL DRAW WARMER AIR
INTO THE REGION. WHILE THE MODELS WERE PUSHING MUCH OF THE AREA
INTO THE 35 TO 45 DEGREE RANGE FOR HIGH TEMPERATURES...LOWERED THEM
A COUPLE OF DEGREES DUE TO THE SNOW PACK.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
332 PM CST MON DEC 10 2012
FROM FRIDAY NIGHT INTO SATURDAY NIGHT...THE MAIN CONCERN WILL BE THE
TRACK OF A SYSTEM MOVING OUT OF THE SOUTHWEST UNITED STATES. AS
THIS SYSTEM MOVES NORTHEAST IT WILL BRING WARM AIR AND GULF
MOISTURE WITH IT. PRECIPITABLE WATER VALUES CLIMB ANYWHERE FROM
150 TO 200 PERCENT OF NORMAL. BOTH THE ECMWF AND GEM HAVE A MUCH
FURTHER NORTH TRACK THAN THE GFS. AS A RESULT...THEY BRING RAIN
INTO SOUTHWEST WISCONSIN AND NORTHEAST IOWA...AND A WINTRY MIX OF
SNOW AND SLEET OR ALL SNOW ACROSS THE REMAINDER OF THE AREA FROM
FRIDAY NIGHT INTO SATURDAY...AND THE PRECIPITATION CHANGES OVER TO
ALL SNOW BEFORE IT ENDS ON SATURDAY NIGHT. MEANWHILE THE GFS IS
ABOUT 6 HOURS SLOWER AND IT ALSO IS FAR ENOUGH SOUTH THAT ONLY THE
AREAS SOUTH OF THE INTERSTATE 90 CORRIDOR WOULD SEE SNOW FROM THIS
SYSTEM. THE GFS ENSEMBLE CONTINUES TO SHOW A WIDESPREAD OF
SOLUTIONS. A FEW OF THEM ARE SIMILAR TO THE ECMWF AND GEM...BUT
THERE ARE ALSO A FEW THAT NO PRECIPITATION AT ALL. OVERALL THE
ECMWF HAS BEEN THE MOST CONSISTENT...SO TRENDED THE FORECAST
TOWARD IT.
&&
.AVIATION...THIS AFTERNOON THROUGH TUESDAY
1130 AM CST MON DEC 10 2012
CIGS/VSBYS WILL CONTINUE TO IMPROVE THIS AFTERNOON AS DRIER HIGH
PRESSURE FROM THE NORTHERN PLAINS BUILDS EAST AND 925-850MB WINDS
GRADUALLY BECOME MORE WESTERLY. THE LOWER LEVEL MVFR/VFR STRATUS
DECKS WILL BE PUSHED EAST AND THE SCT FLURRIES WILL COME TO AN END
AS THE LOWER LEVEL FLOW BECOMES ANTI-CYCLONIC. GOOD VFR BUT COLD
CONDITIONS EXPECTED TONIGHT AS THE HIGH AND A DRY LOW LEVEL AIRMASS
MOVES ACROSS THE AREA. THE HIGH MOVES QUICKLY EAST OF THE AREA ON
TUE. ANOTHER WEAK SFC-500MB TROUGH IS GOING TO SLIDE ACROSS THE
REGION ON TUE. MOISTURE/LIFT INITIALLY LIMITED WITH THIS FEATURE AND
CIGS EXPECTED TO REMAIN VFR THRU TUE MORNING WITH THE INITIALLY DRY
AIRMASS TO OVERCOME. CIGS THEN LOOKING TO DROP TO MVFR TUE
AFTERNOON/EVENING AS THIS TROUGH AXIS PASSES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
332 PM CST MON DEC 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RRS