Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 12/05/11
AREA FORECAST DISCUSSION
NWS DENVER CO
803 PM MST SUN DEC 4 2011
.UPDATE...
&&
.SHORT TERM...LATEST DATA SUGGEST BEST CHANCE FOR ACCUMULATING
SNOWS OVERNIGHT WILL BE MAINLY FROM DENVER SOUTH TO THE PALMER
DIVIDE AND OVER THE SRN FOOTHILLS AND PARK COUNTY. HAD A BURST OF
HEAVIER SNOW FM LATE AFTN INTO THE EARLY EVENING HOURS WHICH
PRODUCED FROM 3 TO 6 INCHES OF SNOW IN THE SRN FOOTHILLS INTO PARK
COUNTY. WILL LEAVE ADVISORIES IN PLACE FOR THE DENVER METRO AREA
BUT SNOW AMOUNTS LOOK TO BE MORE IN THE 2 TO 3 INCH RANGE. FURTHER
NORTH AND EAST SNOW POTENTIAL DOES NOT LOOK THAT GREAT SO WILL
DROP ADVISORIES IN THE NRN FOOTHILLS AND IN THE FORT COLLINS AND
GREELEY AREAS.
.AVIATION...RIGHT NOW SNOW AMOUNTS AT DIA AND BJC SHOULD BE IN
THE 1 TO 2 INCH RANGE WITH UP TO 3 INCHES AT APA. LATEST DATA
SUGGEST LIGHT SNOW WILL GRADUALLY END BY 2 AM OR 3 AM AT DIA WITH
ONLY FLURRIES THROUGH SUNRISE.
&&
.PREV DISCUSSION... /ISSUED 250 PM MST SUN DEC 4 2011/
SHORT TERM...BROAD UPPER TROF COVERS MUCH OF THE WESTERN U.S. WHILE
WATER VAPOR IMAGERY SHOWING NEXT DISTURBANCE DROPPING SOUTH INTO THE
MEAN TROF POSITION OVER UTAH. RUC QG FIELDS SHOWING BEST UPWARD
FORCING OVER WESTERN CO AND WESTERN WYOMING. THE ASSOCIATED COLD
FRONT IS MOVING SOUTH FROM SOUTHERN WYOMING INTO NORTHERN COLORADO
WITH GUSTY NORTHERLY WINDS DEVELOPING BEHIND THE FRONT. CEILINGS ARE
BEGINNING TO LOWER OVER THE FRONT RANGE WITH SOME VERY LIGHT ECHOES
DEVELOPING OVER THE FOOTHILLS. OVERALL...FORECAST IS STILL ON TRACK
WITH MAIN CONCERN SNOW AMOUNTS FOR UPCOMING STORM. SNOW AMOUNTS
EXPECTED TO BE A BIT LOWER THAN THE LAST STORM...AS QG VERTICAL
VELOCITY FIELDS SHOWING THE BEST FORCING ACROSS WESTERN COLORADO
WITH LESSER FORCING OVER NORTHEAST COLORADO AND OVERALL MOISTURE IS
A BIT LOWER. HIGHEST SNOW AMOUNTS WILL BE OVER THE EAST SLOPE FRONT
RANGE FOOTHILLS WITH LESSER AMOUNTS AS YOU MOVE EAST AWAY FROM THE
FOOTHILLS. THERE IS SOME GOOD LOW LEVEL INSTABILITY WITH UPSLOPE UP
TO AROUND 600MB. WILL KEEP THE CURRENT 3-6 SNOWFALL RANGE OVER THE
URBAN CORRIDOR BUT WOULDN`T BE SURPRISED IF AMOUNTS END UP BEING A
BIT LOWER. BIG DROPOFF OF SNOW EAST OF INTERSTATE 25 AND AM
CONCERNED THAT THERE WON`T BE MUCH SNOW OVER EASTERN WELD COUNTY AND
ZONE 45 AND 46 WITH CURRENT ADVISORIES. WILL LEAVE IN PLACE FOR NOW.
FOR THE FOOTHILLS WILL STILL GO WITH 5 TO 10 INCHES. EVEN COLDER
TEMPERATURES FOR TONIGHT AND MONDAY WITH READINGS IN THE SINGLE
DIGITS AND LOWER TEENS FOR THE NEXT 24 HOURS.
LONG TERM...COULD STILL SEE A FEW FLURRIES OCCURRING SOUTH ON
INTERSTATE 70 AS THE STORM CONTINUES TO MOVE SOUTH AND COLD HIGH
PRESSURE SETTLES IN. TEMPERATURES WILL CONTINUE TO PLUMMET TO BELOW
ZERO ACROSS THE AREA. WILL LIKELY SEE VERY COLD TEMPERATURES IN THE
HIGH MOUNTAIN VALLEYS...DROPPING TO AROUND -20 TO -30 BY EARLY
TUESDAY MORNING.
THE PERSISTENT UPPER TROUGH WILL FINALLY MOVE SOUTHEAST OF THE AREA
WITH A SHORT WAVE UPPER RIDGE MOVING OVERHEAD HOWEVER FLOW ALOFT
WILL STILL BE NORTHERLY. TEMPERATURES WILL WARM SLIGHTLY...BUT HAVE
KEPT TEMPERATURES COOLER THAN GUIDANCE AS THE RECENT COLD AIRMASS
WILL BE HARD TO SCOUR OUT AND THE SNOW ON THE GROUND WILL LIKELY
HAVE AN AFFECT AS WELL. HAVE KEPT HIGHS IN THE TEENS TO UPPER 20S
FOR TUESDAY. ON WEDNESDAY...FLOW ALOFT WILL TURN WESTERLY AS A BROAD
UPPER TROUGH OVER CANADA DROPS SOUTH. THE WEST WINDS WILL HELP
TEMPERATURES WARM DURING THE DAY...THEN A WEAK COLD FRONT WILL DROP
SOUTH DURING THE NIGHT. NO REAL PRECIPITATION EXPECT THAT
NIGHT...HOWEVER IT WILL RESULT IN COOLER TEMPERATURES AND A SLIGHT
CHANCE OF SNOW THURSDAY AS ANOTHER SHORTWAVE TROUGH ROUNDS THE
BOTTOM OF THE LARGER TROUGH.
THE LARGE SCALE PATTERN WILL CONTINUE TO TRANSITION EAST FRIDAY TO
BRING A STRONGER UPPER RIDGE OVER THE ROCKIES BRINGING DRIER WEATHER
AND RELATIVELY WARMER AIR FRIDAY AND SATURDAY. INTRODUCING A SLIGHT
CHANCE OF PRECIPITATION FOR SUNDAY AS MODELS DISAGREEING ON WHETHER
THERE WILL BE ANOTHER TROUGH OR RIDGE OVER THE AREA.
AVIATION...CEILINGS BEGINNING TO LOWER NORTH OF THE LOCAL TERMINALS
WITH CIGS OF 5000-7000 FEET AGL UPSTREAM OVER FNL AND GXY. THIS WILL
RESULT IN ILS APPROACHES AROUND 23Z AT DEN AND BJC. THE LIGHT SNOW
NOT FAR BEHIND WITH SNOW NOW AT CYS. MORE WIDESPREAD SNOW AT LOCAL
AIRPORTS DEVELOPING BETWEEN 02-3Z AND CONTINUING THROUGH ABOUT 08Z.
THIS WILL BE THE WINDOW OF MOST OF THE ACCUMULATION SNOW. MOST OF
THE SNOW WILL BECOME VERY LIGHT AND JUST FLURRIES DURING THE DAY ON
MONDAY WITH ACCUMULATIONS UNDER AN INCH. STILL TOTAL ACCUMULATIONS
OF 3 TO 6 INCHES...WITH 2-3 AT DIA...3-4 AT APA AND 4 TO 6 AT BJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MST MONDAY FOR COZ036-037-
039>041.
&&
$$
SHORT TERM...RPK
LONG TERM....KRIEDERMAN
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS DENVER CO
1005 AM MST SAT DEC 3 2011
.UPDATE...RADAR...WEB CAMS AND REPORTS FROM NORTHERN PLAINS
INDICATING SNOW IS DECREASING...OR ENDED IN SPOTS...FROM NORTH TO
SOUTH. STILL SOME AREAS OF MODERATE SNOW INDICATED ON RADAR...AND
THESE AREAS HAVE SHOWN SIGNS OF DECREASING. OVERALL...CURRENT
FORECAST OF DECREASING SNOW ALONG URBAN CORRIDOR AND FOOTHILLS
STILL ON TRACK. WILL BE LETTING THE ADVISORY FOR THOSE AREAS
EXPIRING AT 18Z AND LEAVING THE OTHER ADVISORY GOING TO 21Z. JUST
SOME MINOR TWEAKS WITH REST OF THE GRIDS THIS AFTERNOON.
&&
.AVIATION...CURRENT TAF TRENDS OF GRADUALLY IMPROVING CONDITIONS
FOR THIS AFTERNOON LOOKING ON TRACK. NORTHERLY WINDS TO BE
DIMINISHING BY 21Z...COULD SEE SOME BLOWING SNOW UNTIL THEN AND
WILL LEAVE IN THE TEMPO GROUP.
&&
.PREV DISCUSSION... /ISSUED 358 AM MST SAT DEC 3 2011/
UPDATE...AFTER FURTHER REVIEW I DECIDED TO INCLUDED ZNES 39 AND
40 IN THE WINTER WEATHER ADVISORY THROUGH 11 AM. ALTHOUGH THE SNOW
AMOUNTS WILL BE ON THE LOW SIDE OF THE ADVISY CRITERIA...BUT WIND
MAY COMPOUND THE PROBLEM FOR A TIME. HEAVIEST BAND OF SNOW APPEARS
TO BE FORMING JUST TO THE EAST OF D.I.A. AT THIS TIME. HRRR STILL
SHOWS THE HEAVIEST PCPN EVENTUALLY SHIFTING TO THE PALMER DIVIDE
AREA AFTER 15Z.
SHORT TERM...
PREV DISCUSSION... /ISSUED 310 AM MST SAT DEC 3 2011/
SHORT TERM...STORM SYSTEM MOVING OVER THE REGION THIS MORNING.
SOME BANDED SNOWFALL HAD OCCURRED OVERNIGHT BUT NOT MUCH BANDED
ENHANCEMENT EVIDENT AT THIS TIME. MDLS INDICATE THE WEAK TO MDT QG
ASCENT AT THE SFC AND ALOFT WILL OCCUR PRIOR TO 18Z. WL CONTINUE
WITH THE CURRENT HIGHLIGHTS. SFC WINDS THIS MORNING HAVE BEEN NORTH
TO NORTHWESTERLY PRIMARILY. WITH THIS IN MIND...BEST AREAS FOR
SNOWFALL THIS MORNING WILL BE ALONG THE PALMER DIVIDE. AREAS OF
BLOWING SNOW MAY ALSO BE AN ISSUE OVER THE NORTHEAST PLAINS. IF
GUSTY WINDS OCCUR ALONG THE URBAN CORRIDOR IT WILL LIKELY BE ALONG
THE CHEYENNE RIDGE AND EAST OF INTERSTATE 25 FOR THE MOST PART. A
DRIER NORTHWESTERLY FLOW ALOFT WILL BE OVER THE CWFA TONIGHT.
CLEARING SKIES WILL ALLOW FOR OVERNIGHT LOWS TO DROP TO THE SINGLE
DIGITS.
LONG TERM...ANOTHER SHORT WAVE AND COLD FRONT WILL DROP SOUTH
ACROSS THE ROCKIES ON SUNDAY. THE WAVE WILL ENTER MONTANA SUNDAY
MORNING AND THEN DIVE SOUTH AND CLOSE OFF OVER THE FOUR CORNERS
SUNDAY NIGHT. THE COLD FRONT WILL MOVE THROUGH NORTHEAST COLORADO
AROUND MID DAY SUNDAY. BEST LIFT ASSOCIATED WITH THIS SYSTEM WILL BE
OVER WESTERN AND CENTRAL COLORADO. THERE WILL BE SOME WEAK UPSLOPE
BEHIND THE FRONT. THE HEAVIEST SNOW WILL FALL OVER THE MOUNTAINS AND
FOOTHILLS WITH JUST LIGHT AMOUNTS ALONG THE FRONT RANGE. THE EASTERN
PLAINS MAY EVEN MISS OUT.
AIRMASS BEHIND THE FRONT WILL BE COLD. TEMPERATURES AT 700MB BOTTOM
OUT AT -20C MONDAY MORNING. STRONG SURFACE HIGH...ABOUT 1040MB...
WILL SETTLE OVER THE AREA MONDAY. THIS WILL BRING CLEAR AND COLD
CONDITIONS MONDAY. MOST LOCATIONS WILL REMAIN IN THE TEENS DURING
THE DAY. MONDAY NIGHT WILL BE COLD WITH SOME LOCATIONS FALLING BELOW
ZERO FOR THE FIRST TIME THIS YEAR. DOWNSLOPE WINDS IN AND NEAR THE
FOOTHILLS WILL DEVELOP MONDAY NIGHT LEADING TO WARMING TEMPERATURES
DURING THE NIGHT.
TUESDAY AND WEDNESDAY WILL BE DRY AND COOL AS A WEAK RIDGE MOVES
ACROSS THE REGION. TEMPERATURES WILL WARM BUT REMAIN BELOW NORMAL
WITH HIGHS IN THE 30S TO MID 40S OVER NORTHEAST COLORADO. ANOTHER
TROUGH AND COLD FRONT WILL DROP SOUTH ACROSS THE STATE THURSDAY.
THIS WILL BRINGING COOLER AIR AND A CHANCE OF SNOW FOR THURSDAY AND
FRIDAY. THIS WILL BE MORE OF A GLANCING BELOW THAN THE PREVIOUS
SYSTEM. SO IT SHOULD NOT BE AS COLD AND IF IT SNOWS...SNOW AMOUNTS
WILL BE ON THE LOW SIDE.
AVIATION...NOT MUCH ADJUSTMENTS PLANNED TO THE ONGOING FORECASTS.
SFC VSBYS WILL GENERALLY HOVER BETWEEN 1-2 MILES THIS MORNING...WITH
THE CIGS LESS THAN 2K FT AGL...AND OCCASIONAL VSBYS LESS THAN 1 MILE
AND CIGS LESS THAN 1K FT. GUSTY NORTH TO NORTHWEST WINDS ARE STILL
POSSIBLE BETWEEN 12-18Z. CONDITIONS SHOULD GRADUALLY IMPROVE FM THE
NORTH AND WEST AFTER 18Z. LOWER VSBYS/CIGS WILL LINGER LONGEST OVER
CENTENNIEL AIRPORT WITH GRADUAL IMPROVEMENT THERE AFTER 21Z..
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 2 PM MST THIS AFTERNOON FOR COZ041-
045-046-049.
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ035-
036-038>040.
&&
$$
SHORT TERM...D-L
LONG TERM....MEIER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER CO
358 AM MST SAT DEC 3 2011
.UPDATE...AFTER FURTHER REVIEW I DECIDED TO INCLUDED ZNES 39 AND
40 IN THE WINTER WEATHER ADVISORY THROUGH 11 AM. ALTHOUGH THE SNOW
AMOUNTS WILL BE ON THE LOW SIDE OF THE ADVISY CRITERIA...BUT WIND
MAY COMPOUND THE PROBLEM FOR A TIME. HEAVIEST BAND OF SNOW APPEARS
TO BE FORMING JUST TO THE EAST OF D.I.A. AT THIS TIME. HRRR STILL
SHOWS THE HEAVIEST PCPN EVENTUALLY SHIFTING TO THE PALMER DIVIDE
AREA AFTER 15Z.
&&
.SHORT TERM...
.PREV DISCUSSION... /ISSUED 310 AM MST SAT DEC 3 2011/
SHORT TERM...STORM SYSTEM MOVING OVER THE REGION THIS MORNING.
SOME BANDED SNOWFALL HAD OCCURRED OVERNIGHT BUT NOT MUCH BANDED
ENHANCEMENT EVIDENT AT THIS TIME. MDLS INDICATE THE WEAK TO MDT QG
ASCENT AT THE SFC AND ALOFT WILL OCCUR PRIOR TO 18Z. WL CONTINUE
WITH THE CURRENT HIGHLIGHTS. SFC WINDS THIS MORNING HAVE BEEN NORTH
TO NORTHWESTERLY PRIMARILY. WITH THIS IN MIND...BEST AREAS FOR
SNOWFALL THIS MORNING WILL BE ALONG THE PALMER DIVIDE. AREAS OF
BLOWING SNOW MAY ALSO BE AN ISSUE OVER THE NORTHEAST PLAINS. IF
GUSTY WINDS OCCUR ALONG THE URBAN CORRIDOR IT WILL LIKELY BE ALONG
THE CHEYENNE RIDGE AND EAST OF INTERSTATE 25 FOR THE MOST PART. A
DRIER NORTHWESTERLY FLOW ALOFT WILL BE OVER THE CWFA TONIGHT.
CLEARING SKIES WILL ALLOW FOR OVERNIGHT LOWS TO DROP TO THE SINGLE
DIGITS.
LONG TERM...ANOTHER SHORT WAVE AND COLD FRONT WILL DROP SOUTH
ACROSS THE ROCKIES ON SUNDAY. THE WAVE WILL ENTER MONTANA SUNDAY
MORNING AND THEN DIVE SOUTH AND CLOSE OFF OVER THE FOUR CORNERS
SUNDAY NIGHT. THE COLD FRONT WILL MOVE THROUGH NORTHEAST COLORADO
AROUND MID DAY SUNDAY. BEST LIFT ASSOCIATED WITH THIS SYSTEM WILL BE
OVER WESTERN AND CENTRAL COLORADO. THERE WILL BE SOME WEAK UPSLOPE
BEHIND THE FRONT. THE HEAVIEST SNOW WILL FALL OVER THE MOUNTAINS AND
FOOTHILLS WITH JUST LIGHT AMOUNTS ALONG THE FRONT RANGE. THE EASTERN
PLAINS MAY EVEN MISS OUT.
AIRMASS BEHIND THE FRONT WILL BE COLD. TEMPERATURES AT 700MB BOTTOM
OUT AT -20C MONDAY MORNING. STRONG SURFACE HIGH...ABOUT 1040MB...
WILL SETTLE OVER THE AREA MONDAY. THIS WILL BRING CLEAR AND COLD
CONDITIONS MONDAY. MOST LOCATIONS WILL REMAIN IN THE TEENS DURING
THE DAY. MONDAY NIGHT WILL BE COLD WITH SOME LOCATIONS FALLING BELOW
ZERO FOR THE FIRST TIME THIS YEAR. DOWNSLOPE WINDS IN AND NEAR THE
FOOTHILLS WILL DEVELOP MONDAY NIGHT LEADING TO WARMING TEMPERATURES
DURING THE NIGHT.
TUESDAY AND WEDNESDAY WILL BE DRY AND COOL AS A WEAK RIDGE MOVES
ACROSS THE REGION. TEMPERATURES WILL WARM BUT REMAIN BELOW NORMAL
WITH HIGHS IN THE 30S TO MID 40S OVER NORTHEAST COLORADO. ANOTHER
TROUGH AND COLD FRONT WILL DROP SOUTH ACROSS THE STATE THURSDAY.
THIS WILL BRINGING COOLER AIR AND A CHANCE OF SNOW FOR THURSDAY AND
FRIDAY. THIS WILL BE MORE OF A GLANCING BELOW THAN THE PREVIOUS
SYSTEM. SO IT SHOULD NOT BE AS COLD AND IF IT SNOWS...SNOW AMOUNTS
WILL BE ON THE LOW SIDE.
&&
.AVIATION...NOT MUCH ADJUSTMENTS PLANNED TO THE ONGOING FORECASTS.
SFC VSBYS WILL GENERALLY HOVER BETWEEN 1-2 MILES THIS MORNING...WITH
THE CIGS LESS THAN 2K FT AGL...AND OCCASIONAL VSBYS LESS THAN 1 MILE
AND CIGS LESS THAN 1K FT. GUSTY NORTH TO NORTHWEST WINDS ARE STILL
POSSIBLE BETWEEN 12-18Z. CONDITIONS SHOULD GRADUALLY IMPROVE FM THE
NORTH AND WEST AFTER 18Z. LOWER VSBYS/CIGS WILL LINGER LONGEST OVER
CENTENNIEL AIRPORT WITH GRADUAL IMPROVEMENT THERE AFTER 21Z..
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 2 PM MST THIS AFTERNOON FOR COZ041-
045-046-049.
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ035-
036-038>040.
&&
$$
SHORT TERM...COOPER
LONG TERM....MEIER
AVIATION.....COOPER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
923 PM MST FRI DEC 2 2011
.UPDATE...COMPLEX WEATHER PATTERN EVOLVING ACROSS THE REGION AS
THE NRN ROCKIES TROUGH FORCES THE COLD FRONT TO REACH SOUTHWEST
COLORADO SATURDAY MORNING. THE STRONG TROUGH OVER ARIZONA PIVOTS
NORTHEAST WITH THE STRONGEST DYNAMICAL LIFT OVER WRN COLORADO AT
12Z (5 AM) SATURDAY. THE STRONGEST LIFT IN THE UPPER ATMOSPHERE
COINCIDES WITH THE SURFACE FRONT FROM THE NORTH...AND EXPECT THIS
TIME PERIOD TO BRING THE BEST SNOWFALL RATES TO THE FORECAST AREA.
MOISTURE IS SOMEWHAT LACKING BUT NOT NECESSARILY SPARSE WITH
700 MB SPECIFIC HUMIDITY BETWEEN 2.5 TO 3.0 G/KG. THIS IS GOOD
ENOUGH FOR SIGNIFICANT SNOW ACCUMULATIONS IF THE CRYSTAL GROWTH
TEMPERATURE REGION GETS SATURATED. THE EVENING SOUNDING SHOWS THE
HIGHEST HUMIDITY IN THIS LAYER. WITH UPWARDS MOTION INCREASING
DURING THE NIGHT...EXPECT THIS LAYER TO BECOME SATURATED. IN
ADDITION TO THE DYNAMICAL REASONING FOR THE ACCUMULATING
SNOWFALL...MODELS ALSO SHOW A WEAK TROWAL SIGNATURE THAT WILL ADD
TO THE SNOW POTENTIAL.
THE GFS/NAM DO NOT INDICATE SNOWFALL REACHING ADVISORY OR WARNING
CRITERIA FOR MUCH OF THE REGION (WITH THE EXCEPTION OF THE SWRN
SAN JUANS.) BUT THAT IS NOT NECESSARILY THE CASE WITH THE HIGHER
RESOLUTION MODELS SUCH AS THE 4KM WRF AND 3KM HRRR WHICH INDICATES
SIGNIFICANT ACCUMULATIONS FOCUSED OVER THE SAN JUAN
MOUNTAINS...GRAND MESA...AND POSSIBLY OVER THE SERN UTAH
MOUNTAINS. INCLUDED WINTER WEATHER ADVISORIES FOR THE GRAND AND
UNCOMPAHGRE VALLEY AS THIS APPEARS TO BE THE FIRST SNOW EVENT OF
THIS WINTER SEASON.
FOR NORTHEAST UTAH...NORTHEAST WINDS WILL INCREASE ONCE AGAIN AND
WILL BE A FACTOR (BUT NOT AS STRONG AS THE EVENT THAT OCCURRED
YESTERDAY MORNING.) A SPOTTER REPORT NORTH OF THE COLORADO BORDER
(12 MILES NORTH OF BAGGS) REPORTED SIGNIFICANT DRIFTING SNOW FROM
THE WIND. THIS WIND HAS NOT BEEN OBSERVED IN NW COLORADO BUT THE
TREND IS FOR GUSTY NORTHEAST WINDS AFTER MIDNIGHT. ISSUED WINTER
WEATHER ADVISORY ACROSS THIS REGION FOR THE ACCUMULATING SNOW AND
GUSTY WINDS THAT WILL ACCOMPANY THE FRONT.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
DETERIORATING CONDITIONS WITH MVFR/IFR CONDITIONS BECOMING WIDESPREAD
AFTER 06Z THIS EVENING WITH CIGS BLO BKN010 AND VIS BLO 3SM -SN BR
FREQUENT AT ALL TAF SITES AND MANY AIRFIELDS. IMPROVEMENT AT THE
LOWER VALLEY TAF SITES (KGJT...KMTJ...KRIL AND KEGE) IS EXPECTED
AFTER 18Z SATURDAY AS CIGS IMPROVE AND SNOW DIMINISHES. MOUNTAIN
OBSCURATIONS WILL BE WIDESPREAD THROUGH SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 308 AM MST FRI DEC 2 2011/
SHORT TERM /TONIGHT THROUGH SUNDAY/...
THE CLOSED LOW OVER AZ FINALLY BEGINNING TO OPEN UP AND IS EXPECTED
TO EJECT THROUGH NM AND THE 4 CORNERS TONIGHT AS THE NEXT TROUGH
DIVES DOWN TO REPLACE IT. MOISTURE HAS SPREAD ACROSS MUCH SE UT AND
WRN CO TODAY AND NICELY CAPTURED ON THE 300K POTENTIAL TEMP
SURFACE...WITH LIGHT SNOW REPORTED OVER HIGHER TERRAIN FROM MOUNT
WERNER ABOVE STEAMBOAT SPGS TO GRAND MESA TO THE SAN JUAN MTNS. SNOW
ALSO ALONG THE SRN BASE OF THE SAN JUANS FROM CORTEZ TO PAGOSA IN THE
UPSLOPE FLOW. RUC MODELS SHOWS A COUPLE WAVES OF ENERGY MOVING UP
FROM THE LOW...SO EXPECT SNOW INTENSITY TO VARY THROUGH THE NIGHT
IN SW CO. CURRENT WINTER HIGHLIGHTS FOR THE SAN JUAN/ABAJO/LA SAL
MTNS AND THE DURANGO-PAGOSA AREA LOOK ON TRACK.
THE SECOND SPLITTING TROUGH WAS DROPPING ACROSS ID AND DRIVEN BY A
120 KT UPPER JET OVER THE PAC NW. THIS TROUGH EXPECTED TO PUSH A COLD
FRONT INTO NE UT/NW CO TONIGHT AND THEN INTO SE UT/SW CO SAT AS IT
FORMS A SECOND CLOSED OVER AZ. RATHER NARROW BAND OF MOISTURE
ASSOCIATED WITH THE TROUGH MOVING INTO NW UT...BUT EXPECT SNOW
COVERAGE TO INCREASE OVER NE UT/NW CO TONIGHT AS THE FRONT
INTERACTS WITH THE MOISTURE IN PLACE AHEAD OF THE AZ LOW. THE FRONT
EXPECTED TO SLOW ACROSS THE N LATE TONIGHT...AND A PERIOD DECENT
NORTHEAST OROGRAPHIC WINDS COMBINED WITH COLD ADVECTION SHOULD BRING
3-6 INCHES OF SNOW TO THE ERN UINTA MTNS...ESPECIALLY THEIR NORTH
SLOPES. BUT...NORTHEAST WINDS NOT AS STRONG OR AS LONG IN DURATION
AS THE STORM WED NIGHT...SO REFRAINED FROM ANY HIGHLIGHT FOR THE ERN
UINTAS AT THIS TIME. A PERIOD OF GUSTY NE WINDS LIKELY ACROSS NW CO
SAT MORNING AS WELL...BUT AGAIN NOT NEARLY AS STRONG AS WHAT OCCURRED
THU MORNING.
BOTH NAM AND GFS INDICATE A WEAK 700 MB LOW FORMS OVER WRN CO
TONIGHT/SAT MORNING. BANKING ON ENHANCED LOW LEVEL CONVERGENCE
AND EVENTUAL FRONTAL PASSAGE TO ENHANCE SNOWFALL FROM GRAND MESA TO
THE WEST ELKS. WEST ELKS SHOULD ALSO BENEFIT FROM SOME MOIST
SOUTHERLY OROGRAPHIC FLOW TONIGHT...WHILE TRAILING NORTHERLY FLOW MAY
KEEP SOME LIGHT SNOW OVER GRAND MESA INTO SAT EVENING. AS SUCH...
ELECTED TO INCLUDE THE GRAND MESA AND WEST ELKS /ZONES 9 AND 12/ IN A
LOW-END ADVISORY TONIGHT INTO SAT EVENING FOR 4 TO 9 INCHES OF
SNOW. THE 700 MB LOW SHOULD ALSO BRING SNOW TO MANY CENTRAL VALLEYS
BUT WITH LITTLE ACCUMS EXPECTED.
SNOW DIMINISHES SAT NIGHT WITH CLEARING FROM THE NW. ERN UT/WRN CO
SHOULD BE IN BETWEEN SYSTEMS SUNDAY AS MODELS SHOW YET A THIRD
SPLITTING TROUGH APPROACHING FROM THE N LATE IN THE WEEKEND. WILL
TREND THE CHANCE OF PRECIP UP AGAIN ACROSS THE NORTHERN MTNS SUNDAY
AFTERNOON AS A RESULT.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE EARLY PART OF THE LONG TERM IS A CONTINUATION OF A REPEATING
PATTERN THAT HAS BEEN IN CONTROL SINCE THIS MIDWEEK. THE LAST OF A
SERIES OF SHORTWAVES WILL DROP SOUTHWARD INTO ARIZONA AND AGAIN FORM
A LOW TO OUR SOUTHWEST SUNDAY NIGHT INTO MONDAY. TODAY`S RUNS ARE
FARTHER WEST THAN YESTERDAY`S...WHICH DOES NOT ALLOW THE BEST
MOISTURE/DYNAMICS/OROGRAPHICS TO MOVE OVER OUR FORECAST AREA. THAT
SAID...THIS DISTURBANCE WILL BE IN CLOSE ENOUGH PROXIMITY FOR ANOTHER
ROUND OF MOUNTAIN SNOWFALL...WITH A CHANCE OF SNOW IN MANY VALLEYS.
THE FAVORED AREA WILL SWITCH FROM THE NORTH TO THE SOUTH LATE SUNDAY
NIGHT...WITH CLEARING OVER THE NORTH DURING THE DAY ON MONDAY. WINDS
DO NOT SEEM TO BE AS STRONG AS YESTERDAY`S SYSTEM...SO DO NOT
ANTICIPATE NEARLY AS MUCH BLOWING SNOW.
WE CONTINUE TO SEE SOME DISCREPANCIES IN RUN-TO-RUN AND BETWEEN-MODEL
SOLUTIONS FOR THE UPCOMING LONG TERM PERIOD. TODAY`S RUNS KEEP THE
AREA DRY THROUGH THE REMAINDER OF THE PERIOD. WE SIT UNDER A DRY AND
COLD NORTHWEST FLOW AS HIGH PRESSURE DOMINATES THE WEST COAST THROUGH
THE GREAT BASIN. THIS PATTERN IS NOW PROGGED TO PERSIST THROUGH THE
WORK WEEK. MODELS INDICATE THAT THERE MAY BE A COUPLE WEAK WAVES THAT
BRUSH THE NORTHERN EDGE...BUT THE TIMING AND TRACK IS BOUND TO CHANGE
WITH FUTURE MODEL RUNS.
TEMPERATURES WILL BE BELOW NORMAL IN THE DRY AIR MASS...ESPECIALLY AT
NIGHT. SOME MODIFICATION IS EXPECTED TOWARDS THE END OF THE PERIOD.
ANY WAVES THAT BRUSH THE AREA WILL ACT TO MODIFY TEMPS...AGAIN MAINLY
AT NIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MST SATURDAY FOR ZONES
001>003-006-011-013-020.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR ZONES 009-018-
019.
WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONES 012-
017.
WINTER STORM WARNING UNTIL 3 PM MST SATURDAY FOR ZONES 021>023.
UT...WINTER WEATHER ADVISORY UNTIL NOON MST SATURDAY FOR ZONES 023-
025.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR ZONE 028.
&&
$$
UPDATE.......PF
SHORT TERM...JAD
LONG TERM....EH
AVIATION.....PF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
308 PM CST SAT DEC 3 2011
.SYNOPSIS...
MAIN FEATURE OF INTEREST IS THE UPPER LEVEL LOW OVER LAS VEGAS WITH
A LEAD WAVE EJECTING OVER WESTERN KANSAS AT 18Z. MEANWHILE...
SURFACE LOW IS LOCATED IN SOUTH-CENTRAL KANSAS WITH THE COLD FRONT
EXTENDING NORTH TO FORT DODGE /KFOD/ AND THE UPPER PENINSULA. TEMPS
BEHIND THE FRONT DIVE FROM THE MID AND SOME UPPER 40S INTO THE LOWER
30S. LARGE AREA OF RAIN IN THE WARM SECTOR LIFTED NORTH TODAY WITH
PRECIP AMOUNTS TYPICALLY IN THE ONE HALF TO ONE INCH RANGE. NEXT
ROUND OF PRECIP ASSOCIATED WITH THE MAIN COLD FRONT NOW SPANNING
CENTRAL IOWA AND MUCH OF MISSOURI.
&&
.SHORT TERM...TONIGHT AND SUNDAY...
MAIN FORECAST CONCERN TONIGHT IS THE BEHAVIOR OF THE NEXT ROUND OF
PRECIP. RUC BRINGS THE SURFACE LOW OVER VINTON /KVTI/ BY 03Z THIS
EVENING. THIS IS SLIGHTLY FASTER AND FARTHER NORTHWEST THAN MODEL
FORECASTS HAD BEEN BUT IS IN LINE WITH THE OVERALL TREND TO A WARMER
FORECAST. IN TERMS OF PRECIP...THIS MORE WESTERN TRACK...AS SEEN IN
THE RUC AND CURRENT RADAR TRENDS...SUGGESTS RAIN THROUGH THE EVENING
WITH ONLY A BRIEF CHANGE TO SNOW IN THE FAR NORTHERN COUNTIES BEFORE
PRECIP ENDS LATE TONIGHT/EARLY SUNDAY MORNING. MUCH OF THE AREA TO
BE DRY-SLOTTED OVERNIGHT WITH ONLY THE NORTHERN AND WESTERN SECTIONS
EXPECTED TO SEE WRAP-AROUND PRECIP AS THE LOW RACES OFF TO THE
NORTHEAST. EVEN SO...BUFKIT SOUNDINGS FOR KCID AND KDBQ LIMIT ANY
FROZEN PRECIP TO ONLY AN HOUR OR TWO BEFORE ENDING ALTOGETHER. THUS
HAVE REDUCED SNOW AMOUNTS AND ENDED PRECIP A FEW HOURS EARLIER THAN
PREVIOUS FORECAST. ..DMD..
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY
HIGH PRESSURE AT THE SURFACE MIGRATING THROUGH THE NORTHERN PLAINS
INTO THE UPPER MS VALLEY TO BRING NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES FROM SUNDAY NIGHT THROUGH WEDNESDAY. THROUGH THIS
PERIOD...MODELS IN GENERAL AGREEMENT FEATURING AN UPPER LEVEL
POSITIVE TILT LONG WAVE TROUGH TRANSITIONING EAST THROUGH THE CENTRAL
U.S....SUPPRESSING THE MAIN BAROCLINIC AXIS AND STORM TRACK WELL TO
THE SOUTHEAST. A WAVE OF LOW PRESSURE TRACKING ALONG THE OHIO RIVER
MONDAY WILL SPREAD SNOW INTO PORTIONS OF MO AND IL...AND WILL KEEP
ONLY SLIGHT CHANCE POPS CONFINED TO THE FAR EAST AND SOUTH MONDAY
NIGHT ON THE EXTREME NW EDGE OF THIS SYSTEM. OTHERWISE...NO
PRECIPITATION IS EXPECTED...BUT HIGH LEVEL LIFT AND MOISTURE ALOFT
AHEAD OF THE UPPER TROUGH AXIS WILL FAVOR MOSTLY CLOUDY SKIES FOR
MUCH OF MON THROUGH WED.
THU TROUGH SAT...MODEL CONSENSUS INDICATES A COLD FRONT DROPPING
SOUTH THROUGH THE REGION LATE THURSDAY...FOLLOWED BY MUCH COLDER
TEMPERATURES FRIDAY AND SATURDAY FOLLOWING A FRESH INFLUX OF COLD
AIR AT 850 MB THAT HAS BEEN BUILDING WELL TO THE NORTH. THERE
CONTINUES TO BE CONSIDERABLE DIFFERENCES WITH THE TIMING AND
PLACEMENT OF CRITICAL UPPER LEVEL TROUGHS AND SURFACE FEATURES IN
THIS TIME FRAME...THUS THE POTENTIAL FOR PRECIPITATION REMAINS LOW
CONFIDENCE. THE CURRENT SUITE OF MODELS USED IN THE EXTENDED
SUPPORTS OUR SLIGHT TO LOW END CHANCES FOR LIGHT SNOW FOR THU NIGHT
FOLLOWING THE PASSAGE OF THE COLD FRONT. AHEAD OF THIS FRONT...HIGHS
THURSDAY SHOULD REACH INTO THE 30S IN MOST AREAS. THIS IS FOLLOWED
BY 20S FRIDAY AND SATURDAY WITH OVERNIGHT LOWS IN THE SINGLE DIGITS
AND TEENS. ..SHEETS..
&&
.AVIATION...
IFR CIGS AND VSBYS WILL RETURN TO AREA TAF SITES THIS EVENING AS A
LARGE AREA OF RAIN MOVES ACROSS THE REGION IN ASSOCIATION WITH A
COLD FRONT. RAIN WILL END BETWEEN 04/10Z AND 04/13Z...AND IS
EXPECTED TO CHANGE TO SNOW BRIEFLY BEFORE ENDING AT KCID AND KDBQ.
VFR CONDITIONS ARE EXPECTED TO RETURN TO AREA TAF SITES BY SUNDAY
04/18Z. ALSO OF NOTE...WITH THE PASSAGE OF THE FRONT GUSTY WINDS
WILL SHIFT FROM SOUTHEAST TO NORTH. ..DMD..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
DMD/SHEETS/DMD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
806 AM CST SAT DEC 3 2011
.UPDATE...
DATA THROUGH 12Z SHOWS ALL MODELS ARE VERIFYING HORRIBLY COMPARED
TO REAL DATA. THERE IS A 1009 AND LIKELY A 1008MB LOW IN EXTREME
SOUTHEAST COLORADO. ALL MODELS SHOW AN ERROR DELTA OF 6-7MB IN
THEIR SFC FIELDS AT 12Z. ONLY THE RUC IS CLOSE BUT HAS THE LOW
SLIGHTLY IN ERROR ON POSITION. THUS WILL USE IT AS A TREND FOR THE
REMAINDER OF THE DAY.
CURRENT PRECIPITATION VERIFIES NICELY WITH THE 300K THETA SFC FROM
THE RUC IN TERMS OF FORCING AND CONDENSATION PRESSURE DEFICITS.
USING THIS AS A GUIDE...CATEGORICAL POPS WILL BE SEEN EVERYWHERE
THIS MORNING. THE CURRENT PRECIP IS BEING AIDED BY SOME FAIRLY
SUBSTANTIAL VORT MAXES IN NORTHERN MISSOURI ALONG WITH THE
ISENTROPIC LIFT.
RUC TRENDS INCLUDING THE CURRENT 12Z RUC SHOW THE FORCING
WEAKENING AND CONDENSATION PRESSURE DEFICITS RISING SIGNIFICANTLY
ROUGHLY EAST OF A KEOSAUQUA TO FREEPORT LINE DURING THE AFTERNOON
HOURS. THUS IT IS POSSIBLE THAT THE RAIN MAY END OVER ROUGHLY THE
EASTERN HALF OF THE CWFA DURING THE AFTERNOON HOURS. BY LATE
AFTERNOON THE RUC DOES SHOW CONDENSATION PRESSURE DEFICITS
COLLAPSING ALONG WITH FORCING INCREASING. THIS IS IN ASSOCIATION
WITH THE APPROACH OF THE SFC WAVE.
EXTRAPOLATION OF THE 12 HR RUC FCST SUGGESTS THAT THE SFC LOW WILL
TRACK FROM JUST WEST OF KMCI TO BETWEEN KALO AND KCID DURING THE
EVENING HOURS. IF THIS FURTHER WESTERN TRACK PLAYS OUT...THE
POTENTIAL FOR RAIN MIXING WITH AND CHANGING TO SNOW IN THE WESTERN
CWFA MAY NEED TO BE RE-VISITED WITH THE AFTERNOON FCST PACKAGE.
AN UPDATE TO THE CURRENT FCST HAS BEEN SENT.
..08..
&&
.PREV DISCUSSION... /ISSUED 553 AM CST SAT DEC 3 2011/
AVIATION...
CIGS WILL RANGE FROM IFR TO LOW END MVFR AT KCID/KDBQ WITH VSBYS
1-2SM THROUGH 18Z. VFR CIGS WITH PERHAPS BRIEF 2KFT CIGS WITH
3-5SM CAN BE EXPECTED AT KMLI/KBRL. A DECREASE IN RA INTENSITY IS
EXPECTED 18Z/03-00Z/04 WHICH WILL ALLOW VFR CONDITIONS AT
KMLI/KBRL. KCID/KDBQ WL KEEP 3-5SM WITH CIGS AOB 1KFT AGL. AFT
00Z/04 THE NEXT ROUND OF RA WILL ARRIVE AND DROP VSBYS TO 1-2SM WITH
CIGS AOB 1KFT. KCID/KDBQ MAY SEE A RASN MIX WITH A CHANGE TO ALL
SN AFT 06Z/04.
.08..
PREV DISCUSSION... /ISSUED 331 AM CST SAT DEC 3 2011/
SYNOPSIS...
06Z SFC ANALYSIS HAD A COLD FRONT FROM THE EASTERN DAKOTAS INTO
CENTRAL NEBRASKA. A LOW WAS IN EASTERN COLORADO WITH A FRONT INTO
SOUTHERN NEBRASKA. RADAR TRENDS SHOW A LARGE SHIELD OF WAA
ASSOCIATED WITH A WAVE FROM WISCONSIN BACK INTO WESTERN MISSOURI.
DEW POINTS WERE IN THE 30S AND 40S ACROSS MUCH OF THE MIDWEST WITH
20S OVER THE UPPER MIDWEST AND GREAT LAKES.
SHORT TERM...TODAY AND TONIGHT...
WAA HAS ALLOWED TEMPERATURES TO RISE AND PUSH WBZ SFC TEMPERATURES
TO ABOVE 34 FOR AREAS SOUTH OF HWY 20. ANY THREAT FOR FZRA OR FZDZ
WILL END BY SUNRISE AS WBZ TEMPERATURES CONTINUE TO RISE.
THE INITIAL WAA PRECIP SHIELD WILL MOVE ACROSS THE AREA DURING THE
MORNING HOURS. BASED ON RADAR AND RUC TRENDS THE OVERALL INTENSITY
OF THE PRECIP SHOULD DECREASE DURING THE MID TO LATE MORNING HOURS.
THE QUESTION THEN TURNS TO PRECIP CHANCES FOR THE AFTERNOON.
ALL MODELS SHOW CONDENSATION PRESSURE DEFICITS INCREASING DURING THE
AFTERNOON HOURS. FORCING WEAKENS AND CONVERGENCE IN THE LOWER LEVELS
EITHER WEAKENS OR IS NOT PRESENT. THUS PRECIP CHANCES WILL BE
GREATLY LOWER FOR MOST AREAS GENERALLY EAST OF A KEOK TO KFEP LINE
FOR MUCH OF THE AFTERNOON. THE POTENTIAL DOES EXIST THAT EASTERN
PARTS OF THE CWFA COULD GO COMPLETELY DRY DURING THE AFTERNOON
HOURS. THIS SCENARIO WILL HAVE TO BE RE-EVALUATED.
TONIGHT...THE MAIN SFC LOW ARRIVES AND BRINGS ANOTHER ROUND OF
PRECIPITATION TO THE AREA. WBZ TEMPERATURES ARE ABOVE 34 DEGREES SO
ALL PRECIPITATION WILL BE IN THE FORM OF RAIN DURING THE EVENING
HOURS. AFTER MIDNIGHT...THE RACE BEGINS WITH THE CAA TO SEE IF THE
PRECIP CAN MIX WITH AND CHANGE OVER TO SNOW PRIOR TO SUNRISE. THE
FAR NORTHWEST PART OF THE CWFA WOULD HAVE THE BEST CHANCE. MORE
INTERESTING IS THE DRY SLOT BEING DEPICTED BY THE MODELS. FORCING ON
THETA SURFACES 290-300K SHOW ALL FORCING ENDING VERY LATE TONIGHT
WHICH IS COINCIDENT WITH THE ARRIVAL OF THE DRY SLOT. THUS THE
POTENTIAL DOES EXIST THAT PRECIP MAY END PRIOR TO THE COLD AIR
ARRIVING. IF THIS WOULD OCCUR...THE POTENTIAL FOR A MIX OR A CHANGE
OVER IN THE NORTHWEST CWFA WOULD BE LOW.
IF THE PRECIPITATION DOES END...THE QUESTION THEN BECOMES WHETHER OR
NOT ANY FZDZ COULD DEVELOP. RIGHT NOW THE FCST SOUNDINGS DO NOT
SUGGEST THIS. THUS THE CURRENT THINKING IS THAT A MIX WILL DEVELOP
IN THE NORTHWEST WITH A QUICK CHANGE OVER BEFORE THE PRECIP ENDS.
AMOUNTS NOW LOOK TO BE UNDER AN INCH. ..08..
LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY IS THE TAIL END OF THE SHORT TERM STORM SYSTEM...WITH THE
LAST OF THE DEFORMATION ZONE PRECIPITATION EXITING OFF TO THE
NORTHEAST EARLY IN THE DAY. HAVE SOME SLIGHT CHANCE POPS FOR THE
MORNING HOURS WITH RAIN IN THE EAST...WITH MIXED RAIN SNOW ACROSS
THE NORTH.
ON MONDAY ANOTHER SHORTWAVE EJECTS OUT OF THE UPPER LEVEL TROUGH
AXIS AND MOVES NORTHEAST ALONG THE BAROCLINIC ZONE LEFT BEHIND THE
CURRENT STORM SYSTEM. THIS WAVE IS CURRENTLY FORECAST BY MOST OF
THE MODELS TO STAY SOUTHEAST OF THE FORECAST AREA...BUT THE NAM AND
THE 00Z ECMWF BRING IT FAR ENOUGH NORTH TO BRUSH OUR SOUTHEAST WITH
SOME LIGHT PRECIPITATION. HAVE DECIDED TO GO WITH THE DRIER
SOLUTION FOR NOW...BUT WILL HAVE TO RE-EVALUATE LATER AS NEEDED.
TUESDAY...WEDNESDAY AND EARLY THURSDAY APPEAR QUIET FOR NOW...WITH THE
LONGWAVE TROUGH SHIFTING EAST OF THE AREA AND WEAK RIDGING SETTLING
IN. TEMPERATURES WILL REMAIN COLD WITH HIGHS ONLY IN THE MID 20S TO
MID 30S.
THURSDAY NIGHT AND FRIDAY THE LONGWAVE TROUGH DEEPENS ACROSS THE
CONUS AGAIN AND WE HAVE A COLD FRONT DROP THROUGH THE AREA THURSDAY
NIGHT...FOLLOWED BY SOME SNOW. THIS IS A RELATIVELY NEW FEATURE IN
THE MODELS...BUT BOTH THE GFS AND ECMWF ARE SHOWING IT...SO HAVE
RAISED POPS SLIGHTLY ON THURSDAY NIGHT AND FRIDAY WITH SNOW
PRECIPITATION TYPE. TEMPERATURES STILL BELOW NORMAL WITH HIGHS IN
THE 20S AND LOWER 30S. ..LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
553 AM CST SAT DEC 3 2011
.AVIATION...
CIGS WILL RANGE FROM IFR TO LOW END MVFR AT KCID/KDBQ WITH VSBYS
1-2SM THROUGH 18Z. VFR CIGS WITH PERHAPS BRIEF 2KFT CIGS WITH
3-5SM CAN BE EXPECTED AT KMLI/KBRL. A DECREASE IN RA INTENSITY IS
EXPECTED 18Z/03-00Z/04 WHICH WILL ALLOW VFR CONDITIONS AT
KMLI/KBRL. KCID/KDBQ WL KEEP 3-5SM WITH CIGS AOB 1KFT AGL. AFT
00Z/04 THE NEXT ROUND OF RA WILL ARRIVE AND DROP VSBYS TO 1-2SM WITH
CIGS AOB 1KFT. KCID/KDBQ MAY SEE A RASN MIX WITH A CHANGE TO ALL
SN AFT 06Z/04.
..08..
&&
.PREV DISCUSSION... /ISSUED 331 AM CST SAT DEC 3 2011/
SYNOPSIS...
06Z SFC ANALYSIS HAD A COLD FRONT FROM THE EASTERN DAKOTAS INTO
CENTRAL NEBRASKA. A LOW WAS IN EASTERN COLORADO WITH A FRONT INTO
SOUTHERN NEBRASKA. RADAR TRENDS SHOW A LARGE SHIELD OF WAA
ASSOCIATED WITH A WAVE FROM WISCONSIN BACK INTO WESTERN MISSOURI.
DEW POINTS WERE IN THE 30S AND 40S ACROSS MUCH OF THE MIDWEST WITH
20S OVER THE UPPER MIDWEST AND GREAT LAKES.
SHORT TERM...TODAY AND TONIGHT...
WAA HAS ALLOWED TEMPERATURES TO RISE AND PUSH WBZ SFC TEMPERATURES
TO ABOVE 34 FOR AREAS SOUTH OF HWY 20. ANY THREAT FOR FZRA OR FZDZ
WILL END BY SUNRISE AS WBZ TEMPERATURES CONTINUE TO RISE.
THE INITIAL WAA PRECIP SHIELD WILL MOVE ACROSS THE AREA DURING THE
MORNING HOURS. BASED ON RADAR AND RUC TRENDS THE OVERALL INTENSITY
OF THE PRECIP SHOULD DECREASE DURING THE MID TO LATE MORNING HOURS.
THE QUESTION THEN TURNS TO PRECIP CHANCES FOR THE AFTERNOON.
ALL MODELS SHOW CONDENSATION PRESSURE DEFICITS INCREASING DURING THE
AFTERNOON HOURS. FORCING WEAKENS AND CONVERGENCE IN THE LOWER LEVELS
EITHER WEAKENS OR IS NOT PRESENT. THUS PRECIP CHANCES WILL BE
GREATLY LOWER FOR MOST AREAS GENERALLY EAST OF A KEOK TO KFEP LINE
FOR MUCH OF THE AFTERNOON. THE POTENTIAL DOES EXIST THAT EASTERN
PARTS OF THE CWFA COULD GO COMPLETELY DRY DURING THE AFTERNOON
HOURS. THIS SCENARIO WILL HAVE TO BE RE-EVALUATED.
TONIGHT...THE MAIN SFC LOW ARRIVES AND BRINGS ANOTHER ROUND OF
PRECIPITATION TO THE AREA. WBZ TEMPERATURES ARE ABOVE 34 DEGREES SO
ALL PRECIPITATION WILL BE IN THE FORM OF RAIN DURING THE EVENING
HOURS. AFTER MIDNIGHT...THE RACE BEGINS WITH THE CAA TO SEE IF THE
PRECIP CAN MIX WITH AND CHANGE OVER TO SNOW PRIOR TO SUNRISE. THE
FAR NORTHWEST PART OF THE CWFA WOULD HAVE THE BEST CHANCE. MORE
INTERESTING IS THE DRY SLOT BEING DEPICTED BY THE MODELS. FORCING ON
THETA SURFACES 290-300K SHOW ALL FORCING ENDING VERY LATE TONIGHT
WHICH IS COINCIDENT WITH THE ARRIVAL OF THE DRY SLOT. THUS THE
POTENTIAL DOES EXIST THAT PRECIP MAY END PRIOR TO THE COLD AIR
ARRIVING. IF THIS WOULD OCCUR...THE POTENTIAL FOR A MIX OR A CHANGE
OVER IN THE NORTHWEST CWFA WOULD BE LOW.
IF THE PRECIPITATION DOES END...THE QUESTION THEN BECOMES WHETHER OR
NOT ANY FZDZ COULD DEVELOP. RIGHT NOW THE FCST SOUNDINGS DO NOT
SUGGEST THIS. THUS THE CURRENT THINKING IS THAT A MIX WILL DEVELOP
IN THE NORTHWEST WITH A QUICK CHANGE OVER BEFORE THE PRECIP ENDS.
AMOUNTS NOW LOOK TO BE UNDER AN INCH. ..08..
LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY IS THE TAIL END OF THE SHORT TERM STORM SYSTEM...WITH THE
LAST OF THE DEFORMATION ZONE PRECIPITATION EXITING OFF TO THE
NORTHEAST EARLY IN THE DAY. HAVE SOME SLIGHT CHANCE POPS FOR THE
MORNING HOURS WITH RAIN IN THE EAST...WITH MIXED RAIN SNOW ACROSS
THE NORTH.
ON MONDAY ANOTHER SHORTWAVE EJECTS OUT OF THE UPPER LEVEL TROUGH
AXIS AND MOVES NORTHEAST ALONG THE BAROCLINIC ZONE LEFT BEHIND THE
CURRENT STORM SYSTEM. THIS WAVE IS CURRENTLY FORECAST BY MOST OF
THE MODELS TO STAY SOUTHEAST OF THE FORECAST AREA...BUT THE NAM AND
THE 00Z ECMWF BRING IT FAR ENOUGH NORTH TO BRUSH OUR SOUTHEAST WITH
SOME LIGHT PRECIPITATION. HAVE DECIDED TO GO WITH THE DRIER
SOLUTION FOR NOW...BUT WILL HAVE TO RE-EVALUATE LATER AS NEEDED.
TUESDAY...WEDNESDAY AND EARLY THURSDAY APPEAR QUIET FOR NOW...WITH THE
LONGWAVE TROUGH SHIFTING EAST OF THE AREA AND WEAK RIDGING SETTLING
IN. TEMPERATURES WILL REMAIN COLD WITH HIGHS ONLY IN THE MID 20S TO
MID 30S.
THURSDAY NIGHT AND FRIDAY THE LONGWAVE TROUGH DEEPENS ACROSS THE
CONUS AGAIN AND WE HAVE A COLD FRONT DROP THROUGH THE AREA THURSDAY
NIGHT...FOLLOWED BY SOME SNOW. THIS IS A RELATIVELY NEW FEATURE IN
THE MODELS...BUT BOTH THE GFS AND ECMWF ARE SHOWING IT...SO HAVE
RAISED POPS SLIGHTLY ON THURSDAY NIGHT AND FRIDAY WITH SNOW
PRECIPITATION TYPE. TEMPERATURES STILL BELOW NORMAL WITH HIGHS IN
THE 20S AND LOWER 30S. ..LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
331 AM CST SAT DEC 3 2011
.SYNOPSIS...
06Z SFC ANALYSIS HAD A COLD FRONT FROM THE EASTERN DAKOTAS INTO
CENTRAL NEBRASKA. A LOW WAS IN EASTERN COLORADO WITH A FRONT INTO
SOUTHERN NEBRASKA. RADAR TRENDS SHOW A LARGE SHIELD OF WAA
ASSOCIATED WITH A WAVE FROM WISCONSIN BACK INTO WESTERN MISSOURI.
DEW POINTS WERE IN THE 30S AND 40S ACROSS MUCH OF THE MIDWEST WITH
20S OVER THE UPPER MIDWEST AND GREAT LAKES.
&&
.SHORT TERM...TODAY AND TONIGHT...
WAA HAS ALLOWED TEMPERATURES TO RISE AND PUSH WBZ SFC TEMPERATURES
TO ABOVE 34 FOR AREAS SOUTH OF HWY 20. ANY THREAT FOR FZRA OR FZDZ
WILL END BY SUNRISE AS WBZ TEMPERATURES CONTINUE TO RISE.
THE INITIAL WAA PRECIP SHIELD WILL MOVE ACROSS THE AREA DURING THE
MORNING HOURS. BASED ON RADAR AND RUC TRENDS THE OVERALL INTENSITY
OF THE PRECIP SHOULD DECREASE DURING THE MID TO LATE MORNING HOURS.
THE QUESTION THEN TURNS TO PRECIP CHANCES FOR THE AFTERNOON.
ALL MODELS SHOW CONDENSATION PRESSURE DEFICITS INCREASING DURING THE
AFTERNOON HOURS. FORCING WEAKENS AND CONVERGENCE IN THE LOWER LEVELS
EITHER WEAKENS OR IS NOT PRESENT. THUS PRECIP CHANCES WILL BE
GREATLY LOWER FOR MOST AREAS GENERALLY EAST OF A KEOK TO KFEP LINE
FOR MUCH OF THE AFTERNOON. THE POTENTIAL DOES EXIST THAT EASTERN
PARTS OF THE CWFA COULD GO COMPLETELY DRY DURING THE AFTERNOON
HOURS. THIS SCENARIO WILL HAVE TO BE RE-EVALUATED.
TONIGHT...THE MAIN SFC LOW ARRIVES AND BRINGS ANOTHER ROUND OF
PRECIPITATION TO THE AREA. WBZ TEMPERATURES ARE ABOVE 34 DEGREES SO
ALL PRECIPITATION WILL BE IN THE FORM OF RAIN DURING THE EVENING
HOURS. AFTER MIDNIGHT...THE RACE BEGINS WITH THE CAA TO SEE IF THE
PRECIP CAN MIX WITH AND CHANGE OVER TO SNOW PRIOR TO SUNRISE. THE
FAR NORTHWEST PART OF THE CWFA WOULD HAVE THE BEST CHANCE. MORE
INTERESTING IS THE DRY SLOT BEING DEPICTED BY THE MODELS. FORCING ON
THETA SURFACES 290-300K SHOW ALL FORCING ENDING VERY LATE TONIGHT
WHICH IS COINCIDENT WITH THE ARRIVAL OF THE DRY SLOT. THUS THE
POTENTIAL DOES EXIST THAT PRECIP MAY END PRIOR TO THE COLD AIR
ARRIVING. IF THIS WOULD OCCUR...THE POTENTIAL FOR A MIX OR A CHANGE
OVER IN THE NORTHWEST CWFA WOULD BE LOW.
IF THE PRECIPITATION DOES END...THE QUESTION THEN BECOMES WHETHER OR
NOT ANY FZDZ COULD DEVELOP. RIGHT NOW THE FCST SOUNDINGS DO NOT
SUGGEST THIS. THUS THE CURRENT THINKING IS THAT A MIX WILL DEVELOP
IN THE NORTHWEST WITH A QUICK CHANGE OVER BEFORE THE PRECIP ENDS.
AMOUNTS NOW LOOK TO BE UNDER AN INCH. ..08..
.LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY IS THE TAIL END OF THE SHORT TERM STORM SYSTEM...WITH THE
LAST OF THE DEFORMATION ZONE PRECIPITATION EXITING OFF TO THE
NORTHEAST EARLY IN THE DAY. HAVE SOME SLIGHT CHANCE POPS FOR THE
MORNING HOURS WITH RAIN IN THE EAST...WITH MIXED RAIN SNOW ACROSS
THE NORTH.
ON MONDAY ANOTHER SHORTWAVE EJECTS OUT OF THE UPPER LEVEL TROUGH
AXIS AND MOVES NORTHEAST ALONG THE BAROCLINIC ZONE LEFT BEHIND THE
CURRENT STORM SYSTEM. THIS WAVE IS CURRENTLY FORECAST BY MOST OF
THE MODELS TO STAY SOUTHEAST OF THE FORECAST AREA...BUT THE NAM AND
THE 00Z ECMWF BRING IT FAR ENOUGH NORTH TO BRUSH OUR SOUTHEAST WITH
SOME LIGHT PRECIPITATION. HAVE DECIDED TO GO WITH THE DRIER
SOLUTION FOR NOW...BUT WILL HAVE TO RE-EVAULATE LATER AS NEEDED.
TUESDAY...WEDNESDAY AND EARLY THURSDAY APPEAR QUIET FOR NOW...WITH THE
LONGWAVE TROUGH SHIFTING EAST OF THE AREA AND WEAK RIDGING SETTLING
IN. TEMPERATURES WILL REMAIN COLD WITH HIGHS ONLY IN THE MID 20S TO
MID 30S.
THURSDAY NIGHT AND FRIDAY THE LONGWAVE TROUGH DEEPENS ACROSS THE
CONUS AGAIN AND WE HAVE A COLD FRONT DROP THROUGH THE AREA THURSDAY
NIGHT...FOLLOWED BY SOME SNOW. THIS IS A RELATIVELY NEW FEATURE IN
THE MODELS...BUT BOTH THE GFS AND ECMWF ARE SHOWING IT...SO HAVE
RAISED POPS SLIGHTLY ON THURSDAY NIGHT AND FRIDAY WITH SNOW
PRECIPITATION TYPE. TEMPERATURES STILL BELOW NORMAL WITH HIGHS IN
THE 20S AND LOWER 30S. ..LE..
&&
.AVIATION...
CIGS OF 2-3KFT AGL WILL CONTINUE TO LOWER THROUGH 18Z/03 WITH 1-2KFT
AGL COMMON WITH AREAS BLO 1KFT. GENERAL VSBYS OF 3-5SM ARE EXPECTED
WITH BRIEF PERIODS OF 1-2SM POSSIBLE. A LULL IN PRECIP IS EXPECTED
18Z/03-00Z/04 FOR KMLI/KBRL WHICH MAY RESULT IN CIGS/VSBYS BECOMING
VFR. KCID/KDBQ SHOULD REMAIN MVFR WITH 1-2KFT CIGS AND 3-5SM. AFT
00Z/04 CIGS FOR ALL SITES WILL LOWER TO ARND 1KFT WITH 3-5SM WITH
POTENTIAL FOR 1-2SM AND BLO 1KFT. KCID/KDBQ MAY SEE A RASN MIX OR
ALL SN AFT 08Z/04 BEFORE PRECIPITATION ENDS.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
08/LE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
656 AM EST SAT DEC 3 2011
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN TODAY AND WILL
GRADUALLY SHIFT OFFSHORE BY TOMORROW. SOUTHWEST FLOW BRINGS WARMER
TEMPERATURES FOR SUNDAY AND MONDAY. A WEAK COLD FRONT MOVES INTO
NORTHERN PARTS OF THE AREA ON MONDAY BEFORE STALLING. LOW PRESSURE
TRACKS ALONG THE FRONT ON TUESDAY SPREADING RAIN ACROSS THE
REGION. A COLD FRONT WILL PUSH THROUGH THE AREA ON WEDNESDAY
BRINGING COLDER TEMPERATURES BACK TO THE AREA WITH RAIN CHANGING
TO SNOW BEFORE ENDING.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATE...
CLOUDS HAVE ERODED QUITE A BIT ACROSS THE INTERIOR AND PORTIONS OF
SOUTHERN NH. ADJUSTED CLOUD COVER FOR THIS UPDATE AS WELL AS DEW
POINTS...WITH SOME OF THE HIGHER TERRAIN EXHIBITING SOME VERY DRY
READINGS WHICH THE MODELS DID NOT CAPTURE.
&&
.PREVIOUS DISCUSSION...
STRATUS DECK ASSOCIATED WITH SUBSIDENCE INVERSION HAS BEGUN TO
DIMINISH SLIGHTLY AS LOW LEVEL MOISTURE DECREASES. RUC FORECAST
SOUNDINGS CAPTURE THIS WELL AND SHOW MOISTURE SCATTERING OUT IN THE
NEXT FEW HOURS. CLOUDS WILL LIKELY REMAIN THROUGH DAYBREAK ACROSS
NORTHERN NH AND NORTH CENTRAL MAINE WITH SOME FOG MIXED IN.
ONCE CLOUDS DISAPPEAR TEMPERATURES WILL WARM QUICKLY IN THE DRY
ENVIRONMENT. READINGS WILL TOP OUT NEAR NORMAL VALUES WITH MID TO
UPPER 30S NORTH TO LOWER TO MID 40S SOUTH. IT SHOULD BE A PLEASANT
DAY WITH SUNNY SKIES AND LIGHT WINDS AS HIGH PRESSURE SLOWLY MOVES
OVER THE REGION.
&&
.SHORT TERM /SUNDAY/...
SURFACE HIGH PRESSURE WILL SHIFT OFFSHORE TONIGHT AS UPPER LEVEL
RIDGING BEGINS TO BREAK DOWN. SOUTHERLY FLOW WILL RESULT IN SLIGHTLY
HIGHER TEMPERATURES THAN SATURDAY WITH HIGHS IN THE LOWER 40S NORTH
TO LOWER 50S SOUTH. HIGH CLOUDS WILL BEGIN TO STREAM IN DURING THE
DAY AS THE UPPER LEVEL JET AND MAIN STORM TRACK NEAR...BUT MOST OF
THE DAY SHOULD BE SUNNY TO PARTLY CLOUDY. PRECIPITATION CHANCES WILL
HOLD OFF AS A FRONTAL BOUNDARY STALLS WELL TO OUR NORTHWEST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BROAD... PERSISTENT TROUGH STRETCHING FROM HUDSON BAY TO THE
SOUTHWEST DESERTS WILL BE THE DRIVING FORCE FOR WEATHER FEATURES
ACROSS THE CONTINENT THROUGH NEXT WEEK.
MINOR SHORTWAVE TROUGH CROSSES THROUGH QUEBEC ON SUNDAY NIGHT...
WITH A WEAK SURFACE LOW AND COLD FRONT ACCOMPANYING IT. THIS FRONT
MAY MAKE IT DOWN INTO THE NORTHERN PART OF MAINE AND NEW
HAMPSHIRE... BUT MOST OF THE ENERGY WILL BE TO THE NORTH. RAIN
CHANCES WILL BE LIMITED TO THE MOUNTAINS. SOUTHWEST FLOW AROUND
THE TROUGH AND AROUND THE BACK SIDE OF THE DEPARTING SURFACE HIGH
WILL ADVECT WARMER AIR INTO NORTHERN NEW ENGLAND. EXPECT HIGHS IN
THE 50S WIDESPREAD ESPECIALLY MONDAY AND TUESDAY.
ANOTHER WEAK WAVE CROSSES THROUGH THE SOUTHWESTERLY JET AND OVER
NORTHERN NEW ENGLAND ON TUESDAY WITH MORE WIDESPREAD LIGHT RAIN
EXPECTED. ONSHORE SOUTHERLY FLOW WILL AID IN MOISTURE TRANSPORT
AND ADD OROGRAPHIC LIFT TO INCREASE PRECIPITATION CHANCES.
MODELS DIVERGE ON HOW TO HANDLE THE FINAL PIECE OF THE LARGE SCALE
TROUGH THAT DIGS THROUGH THE SOUTHERN PLAINS ON TUESDAY. GFS IS
MORE PROGRESSIVE... WITH THE ENTIRE TROUGH AXIS SHIFTING EASTWARD
ON WEDNESDAY AND A SURFACE LOW STRENGTHENING RAPIDLY OVER NEW
ENGLAND. UNDER THIS SCENARIO... COLD AIR WILL REMAIN TO THE
NORTHWEST AND PRECIPITATION WILL BE MOSTLY RAIN BEFORE THE TROUGH
AXIS AND SURFACE FRONT PUSH THROUGH ON WEDNESDAY... CHANGING RAIN
TO SNOW BEFORE ENDING. HOWEVER... THE ECMWF ONLY EJECTS A PIECE OF
THE ENERGY FROM THE MAIN TROUGH AXIS ON WEDNESDAY... RESULTING IN
LESS EXTREME SURFACE FEATURES OVER OUR REGION... AND A MORE
QUICKLY ADVANCING COLD FRONT. THE MAIN TROUGH FINALLY CROSSES OUR
AREA ON THURSDAY WITH A SURFACE LOW WELL OFFSHORE AND SNOW MAINLY
OVER SOUTHERN AND CENTRAL NEW ENGLAND. HAVE GONE MAINLY WITH THE
GFS SOLUTION WITH THIS FORECAST AS IT IS MORE CONSISTENT WITH
PRIOR RUNS... BUT THERE IS SOME MERIT TO THE ECMWF SCENARIO AS
TROUGHS WHICH DIG THAT FAR SOUTH TEND TO SLOW DOWN AND TAKE LONGER
TO FINALLY GET PUSHED EASTWARD IN THE FLOW.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...BRIEF MVFR CONDITIONS POSSIBLE UNTIL SUNRISE...
OTHERWISE VFR CONDITIONS AND LIGHT WINDS WILL PREVAIL THROUGH
TONIGHT.
LONG TERM...VFR THROUGH MONDAY. MAY SEE IFR CEILINGS AND RAIN
DEVELOPING TUESDAY.
&&
.MARINE...
SHORT TERM...SCA FOR SEAS OF 5 FT OR HIGHER WILL CONTINUE THROUGH
5 PM.
LONG TERM...SOUTHWEST FLOW PERSISTS AROUND DEPARTING HIGH
PRESSURE. FLOW WILL STRENGTHEN AS FRONT AND UPPER TROUGH APPROACH
FOR WEDNESDAY. SEAS GENERALLY HOVERING RIGHT AROUND THE 5 FT
THRESHOLD TUESDAY ONWARD.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS
AFTERNOON FOR ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS GRAY ME
326 AM EST SAT DEC 3 2011
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN TODAY AND WILL
GRADUALLY SHIFT OFFSHORE BY TOMORROW. SOUTHWEST FLOW BRINGS WARMER
TEMPERATURES FOR SUNDAY AND MONDAY. A WEAK COLD FRONT MOVES INTO
NORTHERN PARTS OF THE AREA ON MONDAY BEFORE STALLING. LOW PRESSURE
TRACKS ALONG THE FRONT ON TUESDAY SPREADING RAIN ACROSS THE
REGION. A COLD FRONT WILL PUSH THROUGH THE AREA ON WEDNESDAY
BRINGING COLDER TEMPERATURES BACK TO THE AREA WITH RAIN CHANGING
TO SNOW BEFORE ENDING.
&&
.NEAR TERM /THROUGH TODAY/...
STRATUS DECK ASSOCIATED WITH SUBSIDENCE INVERSION HAS BEGUN TO
DIMINISH SLIGHTLY AS LOW LEVEL MOISTURE DECREASES. RUC FORECAST
SOUNDINGS CAPTURE THIS WELL AND SHOW MOISTURE SCATTERING OUT IN THE
NEXT FEW HOURS. CLOUDS WILL LIKELY REMAIN THROUGH DAYBREAK ACROSS
NORTHERN NH AND NORTH CENTRAL MAINE WITH SOME FOG MIXED IN.
ONCE CLOUDS DISAPPEAR TEMPERATURES WILL WARM QUICKLY IN THE DRY
ENVIRONMENT. READINGS WILL TOP OUT NEAR NORMAL VALUES WITH MID TO
UPPER 30S NORTH TO LOWER TO MID 40S SOUTH. IT SHOULD BE A PLEASANT
DAY WITH SUNNY SKIES AND LIGHT WINDS AS HIGH PRESSURE SLOWLY MOVES
OVER THE REGION.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
SURFACE HIGH PRESSURE WILL SHIFT OFFSHORE TONIGHT AS UPPER LEVEL
RIDGING BEGINS TO BREAK DOWN. SOUTHERLY FLOW WILL RESULT IN SLIGHTLY
HIGHER TEMPERATURES THAN SATURDAY WITH HIGHS IN THE LOWER 40S NORTH
TO LOWER 50S SOUTH. HIGH CLOUDS WILL BEGIN TO STREAM IN DURING THE
DAY AS THE UPPER LEVEL JET AND MAIN STORM TRACK NEAR...BUT MOST OF
THE DAY SHOULD BE SUNNY TO PARTLY CLOUDY. PRECIPITATION CHANCES WILL
HOLD OFF AS A FRONTAL BOUNDARY STALLS WELL TO OUR NORTHWEST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
BROAD... PERSISTENT TROUGH STRETCHING FROM HUDSON BAY TO THE
SOUTHWEST DESERTS WILL BE THE DRIVING FORCE FOR WEATHER FEATURES
ACROSS THE CONTINENT THROUGH NEXT WEEK.
MINOR SHORTWAVE TROUGH CROSSES THROUGH QUEBEC ON SUNDAY NIGHT...
WITH A WEAK SURFACE LOW AND COLD FRONT ACCOMPANYING IT. THIS FRONT
MAY MAKE IT DOWN INTO THE NORTHERN PART OF MAINE AND NEW
HAMPSHIRE... BUT MOST OF THE ENERGY WILL BE TO THE NORTH. RAIN
CHANCES WILL BE LIMITED TO THE MOUNTAINS. SOUTHWEST FLOW AROUND
THE TROUGH AND AROUND THE BACK SIDE OF THE DEPARTING SURFACE HIGH
WILL ADVECT WARMER AIR INTO NORTHERN NEW ENGLAND. EXPECT HIGHS IN
THE 50S WIDESPREAD ESPECIALLY MONDAY AND TUESDAY.
ANOTHER WEAK WAVE CROSSES THROUGH THE SOUTHWESTERLY JET AND OVER
NORTHERN NEW ENGLAND ON TUESDAY WITH MORE WIDESPREAD LIGHT RAIN
EXPECTED. ONSHORE SOUTHERLY FLOW WILL AID IN MOISTURE TRANSPORT
AND ADD OROGRAPHIC LIFT TO INCREASE PRECIPITATION CHANCES.
MODELS DIVERGE ON HOW TO HANDLE THE FINAL PIECE OF THE LARGE SCALE
TROUGH THAT DIGS THROUGH THE SOUTHERN PLAINS ON TUESDAY. GFS IS
MORE PROGRESSIVE... WITH THE ENTIRE TROUGH AXIS SHIFTING EASTWARD
ON WEDNESDAY AND A SURFACE LOW STRENGTHENING RAPIDLY OVER NEW
ENGLAND. UNDER THIS SCENARIO... COLD AIR WILL REMAIN TO THE
NORTHWEST AND PRECIPITATION WILL BE MOSTLY RAIN BEFORE THE TROUGH
AXIS AND SURFACE FRONT PUSH THROUGH ON WEDNESDAY... CHANGING RAIN
TO SNOW BEFORE ENDING. HOWEVER... THE ECMWF ONLY EJECTS A PIECE OF
THE ENERGY FROM THE MAIN TROUGH AXIS ON WEDNESDAY... RESULTING IN
LESS EXTREME SURFACE FEATURES OVER OUR REGION... AND A MORE
QUICKLY ADVANCING COLD FRONT. THE MAIN TROUGH FINALLY CROSSES OUR
AREA ON THURSDAY WITH A SURFACE LOW WELL OFFSHORE AND SNOW MAINLY
OVER SOUTHERN AND CENTRAL NEW ENGLAND. HAVE GONE MAINLY WITH THE
GFS SOLUTION WITH THIS FORECAST AS IT IS MORE CONSISTENT WITH
PRIOR RUNS... BUT THERE IS SOME MERIT TO THE ECMWF SCENARIO AS
TROUGHS WHICH DIG THAT FAR SOUTH TEND TO SLOW DOWN AND TAKE LONGER
TO FINALLY GET PUSHED EASTWARD IN THE FLOW.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...BRIEF MVFR CONDITIONS POSSIBLE UNTIL SUNRISE...
OTHERWISE VFR CONDITIONS AND LIGHT WINDS WILL PREVAIL THROUGH
TONIGHT.
LONG TERM...VFR THROUGH MONDAY. MAY SEE IFR CEILINGS AND RAIN
DEVELOPING TUESDAY.
&&
.MARINE...
SHORT TERM...SCA FOR SEAS OF 5 FT OR HIGHER WILL CONTINUE THROUGH
5 PM.
LONG TERM...SOUTHWEST FLOW PERSISTS AROUND DEPARTING HIGH
PRESSURE. FLOW WILL STRENGTHEN AS FRONT AND UPPER TROUGH APPROACH
FOR WEDNESDAY. SEAS GENERALLY HOVERING RIGHT AROUND THE 5 FT
THRESHOLD TUESDAY ONWARD.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS
AFTERNOON FOR ANZ150-152-154.
&&
$$
HANES/KIMBLE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1014 PM EST SUN DEC 4 2011
.SYNOPSIS...
HIGH PRESSURE DOMINATES THE MID ATLANTIC REGION THROUGH MONDAY.
A COLD FRONT MOVES INTO THE REGION FROM THE WEST LATE TUESDAY. LOW
PRESSURE RIDES NORTHWARD ALONG THE FRONT WEDNESDAY INTO THURSDAY.
HIGH PRESSURE RETURNS LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS HIGH PRESSURE MOVES SLOWLY OFF THE COAST...LIGHT WINDS ARE
BECOMING SOUTHEAST AND SOUTH...BRINGING INCREASING MOISTURE TO THE
AREA. AS OF 03Z...AREAS OF FOG COVERED THE EASTERN SHORE AND
PORTIONS OF COASTAL SOUTHEAST VIRGINIA AND NORTHEAST NORTH
CAROLINA. SOME AREAS HAVE VISIBILITY UNDER ONE HALF MILE. INLAND
AREAS...THE FOG HAS BEEN INTERMITTENT. RUC AND NAM CONTINUE TO
INDICATE FOG DEVELOPING ACROSS THE CWA...MOST WIDESPREAD EAST OF
I95.
DENSE FOG ADVISORIES MAY BE NEEDED IN THE MORNING AND MID SHIFT
WILL TAKE A CAREFUL LOOK AT THIS OVER THE NEXT FEW HOURS.
NO SIGNIFICANT CHANGE TO THE LOW TEMPERATURES WHICH ARE EXPECTED
TO RANGE FROM THE UPR 30S AND LOWER 40S WEST OF I95 AND THE 40S TO
NEAR 50 ALONG THE COAST.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THE UPR RIDGE JUST OFFSHORE WILL GRADUALLY GET SHOVED EASTWARD
THROUGH TUESDAY IN RESPONSE TO A BROAD UPPER TROUGH DIGGING INTO
THE CENTER OF THE NATION. BY LATE TUESDAY...THE UPR TROUGH WILL
PUSH A COLD FRONT TOWARD THE MID-ATLANTIC REGION WITH THIS
FEATURE SAGGING SOUTHWARD THROUGH VA AND INTO NE NC BY 12Z WED. AS
THE UPR TROUGH CONTINUES TO DIG AND A CUTOFF LOW DEVELOPS OVER THE
SOUTHERN PLAINS/LOWER MS VALLEY ON WED...THE FRONT WILL STALL OUT
ACROSS THE CAROLINAS WITH SFC LOW PRESSURE DEVELOPING ALONG IT.
UNFORTUNATELY...CONFIDENCE IN THE FORECAST BY WEDNESDAY IS LOW
GIVEN THE LARGE SPREAD IN THE MODELS AT THAT TIME...SO HAVE NOT
GONE HIGHER THAN 50% POP FOR TUESDAY NIGHT AND WEDNESDAY. IN THE
MEANTIME...MOISTURE WILL CONTINUE TO INCREASE FROM MONDAY INTO
TUESDAY ALLOWING FOR MOSTLY CLOUDY CONDITIONS. WILL KEEP DRY WX IN
THE FORECAST THROUGH MONDAY EVENING...BEFORE ADDING LOW CHC POPS
INTO WESTERN AREAS BY EARLY TUESDAY MORNING. AS THE FRONT NEARS ON
TUESDAY...WILL SEE CHC POPS (30-40%) SPREAD EASTWARD. HIGHEST POPS
(~50%) AGAIN WILL BE TUESDAY NIGHT/WEDNESDAY AS THE FRONT STALLS
JUST SOUTH OF OUR CWA. HIGHS MONDAY/TUESDAY IN THE 60S...EXCEPT
AROUND 70 IN THE VA TIDEWATER/NE NC. WEDNESDAY`S HIGHS WILL DEPEND
OF PCPN COVERAGE BUT SHOULD BE IN THE MID 50S NW TO THE LOW 60S SE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LO CONFIDENCE FCST MIDWEEK...HV CHOSEN TO GO CLSR TO COMBO OF
SREF/ECMWF SOLN WRT FNT PLCMNT AND EVENTUAL SFC LO PRES DVLPMNT/MVG
WED NGT INTO THU. THAT WOULD HV MNLY N WNDS...AND WDSPRD CVRG OF RA
(FOR NOW CAPPING POPS AT 50% OVR MOST OF THE FA). LO PRES XPCTD TO
MV OUT TO SEA THU NGT...W/ DRYING/SEASONABLY COLD WX FM FRI THROUGH
NEXT WKND. ACCOMPANYING THE ARRIVAL OF THE COLD AIR WL BE GUSTY NW
WNDS THU NGT INTO FRI.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
FOLLOWED CLOSE TO NAM WITH RESPECT TO FOG FORMATION IN THE TAFS AND
BROUGHT VISIBILITIES TO IFR IN TEMPO GROUPS BY 03Z AT SBY ECG AND
PHF DUE TO CURRENT TRENDS AND RUC BUFKIT. KEPT VISIBILITY NO LOWER THAN
3 MILES AT ORF. BUT EVENTUALLY DROPPED THEM BELOW ONE MILE
PREDOMINANTLY AT RIC SBY AND PHF. THERE ARE SOME INDICATIONS IN
THE NAM BUFKIT THAT IFR VISIBILITY AT ECG MAY BE INTERMITTENT.
CONDITIONS WILL BE SLOW TO IMPROVE DUE TO DEEP INVERSION AND VERY
LIGHT SURFACE WINDS. IN THE MORNING. IFR STRATUS EXPECTED UNTIL
14-16Z AT ALL BUT ORF.
OUTLOOK...THE NEXT CHANCE FOR RAIN COMES MID WEEK WITH THE
APPROACH OF A SLOW MOVING COLD FRONT.
&&
.MARINE...
SFC HI PRES OFFSHR RMNS IN CONTROL OVR THE WTRS THROUGH ERY PART OF
THE WK. SE TO S WNDS AOB 10 KT XPCTD THROUGH MON...W/ GRDL INCRS IN
SPDS MON NGT INTO TUE. SLO MVG CDFNT APPROACHES FM THE WNW TUE/TUE
NGT...THEN XPCTD TO SETTLE OVR THE WTRS WED. GOING CLSR TO
SREF/ECMWF SOLN W/ EVENTUALLY PUSH SWD OF FNTL BNDRY ON WED. WL HV
WNDS BCM MNLY N OVR THE FA ON WED AS FNTL SETTLES INTO FA.
TRACK/INSTENSITY OF SFC LO PRES ALG THE FNT LT WED INTO THU STILL
PROBLEMATIC ATTM. MOD/STRNG NW WNDS XPCTD BEHIND DEPARTING LO
PRES LT THU INTO FRI. NO HEADLINES NEEDED THROUGH MON NGT/TUE.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDM
NEAR TERM...MAM/LSA
SHORT TERM...JDM
LONG TERM...ALB
AVIATION...JEF/LSA
MARINE...ALB
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
739 PM EST SUN DEC 4 2011
.SYNOPSIS...
HIGH PRESSURE DOMINATES THE MID ATLANTIC REGION THROUGH MONDAY.
A COLD FRONT MOVES INTO THE REGION FROM THE WEST LATE TUESDAY. LOW
PRESSURE RIDES NORTHWARD ALONG THE FRONT WEDNESDAY INTO THURSDAY.
HIGH PRESSURE RETURNS LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
FOG DEVELOPING ALONG SOME OF THE COASTAL SECTIONS ESPECIALLY ON
THE EASTERN SHORE. VISIBILITY LESS THAN A MILE AT WAL OXB AND LFI
AS OF 0030Z. RUC AND NAM INDICATE WIDESPREAD FOG OVER MOST AREAS
EAST OF I95...SOME OF IT STARTING BETWEEN 00 AND 03Z NEAR THE
COAST. UPDATED GRIDS TO INDICATE THIS. IT MAY BE SLOW TO IMPROVE
AFTER SUNRISE AND KEPT AREAS OF FOG IN THE GRIDS TIL 14Z FOR NOW.
ADVISORIES FOR DENSE FOG COULD BE NEEDED BUT HELD OFF FOR NOW.
AREAS OF HIGH CLOUDS MAY BE A DETERRENT. NOT SURE OF THE EXTENT OF
ANY DENSE FOG AT THIS POINT.
OTHERWISE...NO SIGNIFICANT CHANGES TO THE FORECAST EXCEPT TO
INDICATE SKIES STARTING OUT CLEAR OVER INLAND AREAS OF SOUTHERN
VIRGINIA.
PREVIOUS DISCUSSION...
HIGH PRESSURE AT THE SFC AND ALOFT WILL BE CENTERED JUST OFFSHORE
HEADING INTO TONIGHT. THIS WILL KEEP ANY WET WX OUT OF THE
FORECAST. INCREASING SW FLOW ALOFT WILL ALLOW SOME MID/HIGH CLOUDS
TO MOVE THROUGH OVERNIGHT SO HAVE GONE WITH A PARTLY CLOUDY SKY.
LIGHT SE FLOW IN THE LOW LEVELS WILL ALLOW FOR AREAS OF LOW
STRATUS AND PATCHY FOG LATE. LOWS WILL BE IN THE UPR 30S OVER THE
PIEDMONT TO THE UPR 40S ALONG THE COAST.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THE UPR RIDGE JUST OFFSHORE WILL GRADUALLY GET SHOVED EASTWARD
THROUGH TUESDAY IN RESPONSE TO A BROAD UPPER TROUGH DIGGING INTO
THE CENTER OF THE NATION. BY LATE TUESDAY...THE UPR TROUGH WILL
PUSH A COLD FRONT TOWARD THE MID-ATLANTIC REGION WITH THIS
FEATURE SAGGING SOUTHWARD THROUGH VA AND INTO NE NC BY 12Z WED. AS
THE UPR TROUGH CONTINUES TO DIG AND A CUTOFF LOW DEVELOPS OVER THE
SOUTHERN PLAINS/LOWER MS VALLEY ON WED...THE FRONT WILL STALL OUT
ACROSS THE CAROLINAS WITH SFC LOW PRESSURE DEVELOPING ALONG IT.
UNFORTUNATELY...CONFIDENCE IN THE FORECAST BY WEDNESDAY IS LOW
GIVEN THE LARGE SPREAD IN THE MODELS AT THAT TIME...SO HAVE NOT
GONE HIGHER THAN 50% POP FOR TUESDAY NIGHT AND WEDNESDAY. IN THE
MEANTIME...MOISTURE WILL CONTINUE TO INCREASE FROM MONDAY INTO
TUESDAY ALLOWING FOR MOSTLY CLOUDY CONDITIONS. WILL KEEP DRY WX IN
THE FORECAST THROUGH MONDAY EVENING...BEFORE ADDING LOW CHC POPS
INTO WESTERN AREAS BY EARLY TUESDAY MORNING. AS THE FRONT NEARS ON
TUESDAY...WILL SEE CHC POPS (30-40%) SPREAD EASTWARD. HIGHEST POPS
(~50%) AGAIN WILL BE TUESDAY NIGHT/WEDNESDAY AS THE FRONT STALLS
JUST SOUTH OF OUR CWA. HIGHS MONDAY/TUESDAY IN THE 60S...EXCEPT
AROUND 70 IN THE VA TIDEWATER/NE NC. WEDNESDAY`S HIGHS WILL DEPEND
OF PCPN COVERAGE BUT SHOULD BE IN THE MID 50S NW TO THE LOW 60S SE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LO CONFIDENCE FCST MIDWEEK...HV CHOSEN TO GO CLSR TO COMBO OF
SREF/ECMWF SOLN WRT FNT PLCMNT AND EVENTUAL SFC LO PRES DVLPMNT/MVG
WED NGT INTO THU. THAT WOULD HV MNLY N WNDS...AND WDSPRD CVRG OF RA
(FOR NOW CAPPING POPS AT 50% OVR MOST OF THE FA). LO PRES XPCTD TO
MV OUT TO SEA THU NGT...W/ DRYING/SEASONABLY COLD WX FM FRI THROUGH
NEXT WKND. ACCOMPANYING THE ARRIVAL OF THE COLD AIR WL BE GUSTY NW
WNDS THU NGT INTO FRI.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
FOLLOWED CLOSE TO NAM WITH RESPECT TO FOG FORMATION IN THE TAFS AND
BROUGHT VISIBILITIES TO IFR IN TEMPO GROUPS BY 03Z AT SBY ECG AND
PHF DUE TO CURRENT TRENDS AND RUC BUFKIT. KEPT VISIBILITY NO LOWER THAN
3 MILES AT ORF. BUT EVENTUALLY DROPPED THEM BELOW ONE MILE
PREDOMINANTLY AT RIC SBY AND PHF. THERE ARE SOME INDICATIONS IN
THE NAM BUFKIT THAT IFR VISIBILITY AT ECG MAY BE INTERMITTENT.
CONDITIONS WILL BE SLOW TO IMPROVE DUE TO DEEP INVERSION AND VERY
LIGHT SURFACE WINDS. IN THE MORNING. IFR STRATUS EXPECTED UNTIL
14-16Z AT ALL BUT ORF.
OUTLOOK...THE NEXT CHANCE FOR RAIN COMES MID WEEK WITH THE
APPROACH OF A SLOW MOVING COLD FRONT.
&&
.MARINE...
SFC HI PRES OFFSHR RMNS IN CONTROL OVR THE WTRS THROUGH ERY PART OF
THE WK. SE TO S WNDS AOB 10 KT XPCTD THROUGH MON...W/ GRDL INCRS IN
SPDS MON NGT INTO TUE. SLO MVG CDFNT APPROACHES FM THE WNW TUE/TUE
NGT...THEN XPCTD TO SETTLE OVR THE WTRS WED. GOING CLSR TO
SREF/ECMWF SOLN W/ EVENTUALLY PUSH SWD OF FNTL BNDRY ON WED. WL HV
WNDS BCM MNLY N OVR THE FA ON WED AS FNTL SETTLES INTO FA.
TRACK/INSTENSITY OF SFC LO PRES ALG THE FNT LT WED INTO THU STILL
PROBLEMATIC ATTM. MOD/STRNG NW WNDS XPCTD BEHIND DEPARTING LO
PRES LT THU INTO FRI. NO HEADLINES NEEDED THROUGH MON NGT/TUE.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDM
NEAR TERM...MAM/JDM/LSA
SHORT TERM...JDM
LONG TERM...ALB
AVIATION...JEF/LSA
MARINE...ALB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
207 PM CST SAT DEC 3 2011
.DISCUSSION...
SNOW HAS BEGUN TO SRPEAD INTO S MN AND WILL CONTINUE TO EXPAND NE
RAPIDLY DURING THE REMAINDER OF THE AFTERNOON. A BIT OF SATURATION
LEFT TO DO IN LOWER LEVELS BUT CIGS ARE BEGINNING TO LOWER ACROSS
S MN. IR SATELLITE SHOWS ELONGATED VORT FROM W KS INTO SC NEB
LIFTING NE. GFS/NAM SIMILAR ON TIMING BRINGING MAIN VORT INTO SC MN
BY 00Z AND THEN LIFTING INTO CENTRAL WI BY 06Z. GFS HAS INCREASED
QPF VALUES A BIT MORE TOWARD THE NAM SOLUTION. INCREASED SNOW
AMOUNTS A BIT ACROSS AREAS FROM MKT TO SE METRO BASED LARGELY ON
TRACK OF SURFACE/850 MB LOW CENTERS. HEAVY SNOW OFTEN SETS UP 70
TO 90 MILES N OF 850 MB LOW TRACK..AND 850 MB LOW TRACKS FROM SW
IA TO JUST S OF LSE BY 06Z THEN INTO E UPR MICHIGAN BY 12Z. KEPT
SNOW AMOUNTS IN THE 3 TO 6 INCH ADVISORY. FAVORABLE ISENTROPIC
LIFT COMES THRU RATHER QUICKLY WITH 3-3.5G/KG SO HESITATE TO GO
ANY HIGHER. WILL BE A PERIOD FROM AROUND 22Z TO 05Z WHERE ADVISORY
AREA WILL BE UNDER STRONG UPPER DIVERENGE FROM COUPLED UPPER JET...
FAVORABLE DENDRITIC TEMPERATURES AND STRONG 600 MB FULL WIND
FRONTOGENSIS WHICH COULD BRING A PERIOD OF A FEW HOURS OF
VISIBILITY INTO THE 1/2 SM RANGE AS FAR N AS MSP. LIKE THE TIMING
OF THE RUC BUFKIT SNOW ACCUMS IN THAT WINDOW. DECREASED SNOW
AMOUNTS SLIGHTLY IN W SIDE OF ADVY AREA AROUND SPRINGFIELD AND
GAYLORD. ADVISORY WILL LIKELY BE ABLE TO BE EXPIRED BY 06Z ACROSS
MUCH OF THE MN CWA WITH NO SIGNIFICANT WIND EXPECTED IN WAKE OF
SNOW.
COOLER FOR SUNDAY...BUT TROF DROPPING OUT OF CANADA WILL BACK
WINDS ENUF TO KEEP MAIN PUSH OF COLD AIR NORTH OF AREA. AS THIS
SYSTEM MOVES THRU COLD AIR WILL MOVE IN FOR MONDAY WITH HIGHS ONLY
IN THE TEEN TO MID 20S. SLIGHT MODERATION FOR WEDNESDAY AS WEAK
TROF MOVES ACROSS AREAK. AFTER THAT AREA REMAINS IN COLD AND DRY
NW FLOW AT LEAST UNTIL NEXT WEEKEND.
WITH SNOW COVER EXPECTED TONIGHT ACROSS S MN INTO WC WI WILL BE SOME
SOME MORNINGS WHERE WE SHOULD GET MIN TEMPS DOWN NEAR
ZERO...TUESDAY AND PROBABLY AGAIN FRIDAY/SATURDAY.
.AVIATION... /18Z TAF ISSUANCE/
STRONG LIFT NOW MOVING NORTHEAST ACROSS IOWA. SATURATION DEVELOPING
OVER FAR SOUTHERN MN WITH MVFR/IFR CONDITIONS OVER THE SOUTHEAST
CORNER OF THE STATE AND NOW LIFTING TO THE NORTH ACROSS WEST CENTRAL
WISCONSIN. EXPECT SNOW LINE TO REMAIN EAST OF KSTC TO NEAR KRWF
DURING THE EVENT. LOWEST CEILINGS LIFR/IFR TO REMAIN IN SNOW AREA
OVER THE EASTERN AREAS. COULD STILL SEE SOME 1/2SM SN REPORTS OVER
SOUTHEAST MN/WEST CENTRAL WISCONSIN INTO THE EVENING AS THIS SYSTEM
LIFTS NORTHEAST. MVFR CIGS EXPECTED INTO KAXN WITH CAA PATTERN
BEHIND SURFACE FRONT. THIS MAY LINGER LONGER INTO THE NIGHT AS
WELL...BEFORE SIGNIFICANT DRYING OCCURS. OTHERWISE...SNOW EXITING
THE EASTERN PORTION OF THE AREA 06Z-12Z SUNDAY PERIOD WITH
INCREASING CEILING HEIGHTS TO MVFR. SHOULD MAINTAIN MVFR CIGS
THROUGH THE MORNING. WITH BOUNDARY IN THE VCNTY EXPECT NORTHWEST
WINDS 10 KNOTS OR LESS OVER THE WESTERN AREAS AND LIGHT
SOUTH/SOUTHEAST BECOMING NORTH OVER THE EASTERN AREAS.
KMSP...MOISTURE/LIFT MOVING NORTH QUICKLY THIS AFTERNOON WITH
RAPIDLY CHANGING CONDITIONS DEVELOPING AFTER 21Z WITH SNOW AND
IFR/LIFR DEVELOPING THROUGH 00Z. APPEARS HEAVIEST ACCUMULATIONS
STILL OCCURRING IN THE 23Z-05Z PERIOD. ACCUMULATION AT THE AIRPORT
SHOULD RANGE FROM 2-3 INCHES. IMPROVING CONDITIONS AFTER 05Z WITH
LOWER CLOUDS REMAINING THROUGH MUCH OF SUNDAY MORNING...THOUGH VFR
POSSIBLE AFTER 14Z SUNDAY. LIGHT SOUTH WINDS EXPECTED TO BECOME MORE
NORTHWEST DURING THE PERIOD...BUT SHOULD REMAIN 10 KNOTS OR LESS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR ANOKA-BLUE
EARTH-BROWN-CARVER-CHISAGO-DAKOTA-FARIBAULT-FREEBORN-
GOODHUE-HENNEPIN-LE SUEUR-MARTIN-NICOLLET-RAMSEY-RICE-SCOTT-
SIBLEY-STEELE-WASECA-WASHINGTON-WATONWAN.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
BAP/DWE
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 PM EST SUN DEC 4 2011
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND SOUTHWESTWARD INTO CENTRAL NC THROUGH
TUESDAY. MEANWHILE...A FRONTAL SYSTEM WILL APPROACH SLOWLY FROM THE
WEST AND AFFECT OUR REGION MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 1000 PM SUNDAY...
THE PROBLEM OF THE NIGHT CONTINUES TO BE THE POTENTIAL FOR DENSE FOG
AND LOW STRATUS DEVELOPMENT.
1030+ MB SURFACE HIGH PRESSURE WAS LOCATED OFFSHORE OF THE
MID-ATLANTIC COAST WITH THE RIDGE AXIS EXTENDING SW DIRECTLY OVER
OUR REGION THIS EVENING. THE SURFACE WINDS WERE VERY LIGHT AND
MAINLY FROM THE NNE OVER OUR SE... WITH CALM CONDITIONS UNDER RIDGE
AXIS OVER OUR NW ZONES. THE LATEST SATELLITE DATA INDICATED
SCATTERED AREAS OF STRATOCUMULUS WITH BASES WELL UP AT 6500 FEET OR
SO. THE WV SATELLITE DATA INDICTED HIGH MOISTURE INCREASING ALOFT IN
THE BROAD SW FLOW WITH MOST OF THE PLUME OF MOISTURE AIMING WEST OF
THE APPALACHIANS.
THE LATEST HRRR INDICATES AN EXPLOSION OF FOG/LOW CLOUD DEVELOPMENT
OVER THE NORTHERN COASTAL PLAIN SHORTLY... THEN EXPANDING/DEVELOPING
WESTWARD INTO THE NORTHERN AND EASTERN PIEDMONT BETWEEN 08Z-12Z.
SURFACE OBSERVATIONS WERE ALREADY INDICATING THIS PROCESS WAS
BEGINNING OVER SE VA AND NE NC. THE VERTICAL MOISTURE/WIND PROFILES
OVER THE NORTHEAST AND NORTH CENTRAL NC ZONES ARE MOST FAVORABLE FOR
THE DENSE FOG AND LOW STRATUS. WE WILL GO WITH THE LATEST HRRR
FORECAST WHICH HAS STRONG SUPPORT FROM THE LATEST NAM... AND CURRENT
ANALYZED DATA. NO OTHER CHANGES ARE NEEDED AT THIS TIME. -BADGETT
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 242 PM SUNDAY...
MONDAY:
SLOW MOVING FRONTAL ZONE ASSOCIATED WITH THE FULL LATITUDE TROUGH
ALOFT TO THE WEST OF THE AREA WILL REMAIN WEST OF THE MOUNTAINS ON
MONDAY. AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO
INCREASE A GOOD 15 METERS OR SO FROM TODAY. HOWEVER... INCREASE IN
AFOREMENTIONED MOISTURE AND CLOUD COVER WILL HELP OFFSET THE
INCREASE IN LOW LEVEL THICKNESS VALUES... AS SKIES WILL ONLY IMPROVE
INTO THE PARTLY SUNNY TO MOSTLY CLOUDY RANGE (MORE IMPROVEMENT
SOUTHEAST/EAST VS NORTHWEST). THUS... EXPECT TEMPS WILL BE SIMILAR
TO TODAYS VALUES... MAYBE A BIT WARMER ACROSS THE SOUTHEAST. THIS
YIELDS HIGH TEMPS RANGING FROM AROUND 60 IN THE NORTHWEST TO NEAR 70
IN THE SOUTHEAST. IN ADDITION... CANNOT RULE OUT A FEW WAA SHOWERS
OR SPRINKLES MAINLY ACROSS THE WEST/NORTHWEST (UPSLOPE FLOW).
HOWEVER... WITH A LOT OF DRY AIR ALOFT AND AMOUNT OF MOISTURE AND
LIFT QUITE SHALLOW WILL GO WITH A DRY FORECAST.
MONDAY NIGHT THROUGH TUESDAY NIGHT...SURFACE RIDGE OVER THE FORECAST
AREA GRADUALLY WEAKENS AND SHIFTS EWD MONDAY NIGHT THROUGH TUESDAY.
THIS WILL ALLOW A SURFACE COLD FRONT ASSOCIATED WITH POSITIVELY TILT
UPPER TROUGH (EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN
ROCKIES) TO EDGE EAST...POSSIBLY ENTERING THE NC MOUNTAINS TUESDAY
MORNING. RETURN FLOW ON THE BACKSIDE OF THE HIGH WILL ADVECT LOW
LEVEL MOISTURE INTO CENTRAL NC. RH CROSS SECTIONS SUGGEST MOISTURE
MAINLY CONFINED TO THE LOWEST 5000FT WITH A DECENT LAYER OF DRY AIR
IN THE MID LAYERS OF THE ATMOSPHERE. BEST ISENTROPIC LIFT IN THE
295-300K LAYER OCCURRING NEAR OUR WESTERN PERIPHERY. WHILE COULD SEE
A FEW SPRINKLES ALONG AND EAST OF HIGHWAY 1...BETTER POTENTIAL FOR
MEASURABLE LIGHT PRECIP WILL BE OVER OUR WESTERN COUNTIES...MAINLY
AFTER MIDNIGHT (LIKELY CLOSER TO DAYBREAK). HAVE ADJUSTED POPS
MONDAY NIGHT...KEEPING THE EVENING HOURS DRY THEN LIMITING SLIGHT
CHANCE POPS TO THE WESTERN THIRD OF THE REGION.
BEST CHANCE FOR LIGHT PRECIP AMOUNTS TUESDAY-TUESDAY NIGHT WILL
REMAIN IN VICINITY OF THE SURFACE BOUNDARY THAT WILL INCH E-SE
TOWARD THE NW COUNTIES DURING THIS PERIOD AS DEEP SW FLOW AND
STUBBORN HIGH OFFSHORE WILL RESULT IN LITTLE PUSH TO THIS FEATURE.
THUS...POPS ACROSS CENTRAL NC WILL GRADUATE FROM SOLID CHANCE FAR
N-NW TO SMALL CHANCE SE. MAY SEE A PERIOD WHERE PRECIP ACROSS THE N
AND NW LIMITED/NON-EXISTENT BUT DIFFICULT TO DETERMINE THIS FAR OUT
WHEN THIS WILL OCCUR. PRECIP AMOUNTS TUESDAY INTO TUESDAY NIGHT
SHOULD REMAIN LIGHT (LESS THAN A QUARTER OF INCH MOST LOCALES WITH
JUST A FEW HUNDREDTHS PROBABLE IN THE SE) AS LIFT FOR PRECIP
GENERATION RELATIVELY WEAK.
TEMPS MONDAY NIGHT THROUGH TUESDAY NIGHT SHOULD REMAIN MILD FOR THIS
TIME OF YEAR... AND MAINLY DEPENDENT ON THE AMOUNT OF PRECIP
COVERAGE OVER THE NW. MIN TEMPS LOW-MID 50S. HIGH TEMPS TUESDAY MID
60S NW TO AROUND 70/LOWER 70S SE.
WEDNESDAY AND WEDNESDAY NIGHT...
FORECAST CONFIDENCE LOWER THAN NORMAL BEGINNING THIS PERIOD AS
MEDIUM RANGE GUIDANCE DIFFER QUITE A BIT WITH EASTWARD TRANSLATION
OF ENERGY IN THE SOUTHERN STREAM. THE ECMWF-GFS DIFFERENCE LAST
NIGHT WAS ABOUT 12HRS FROM EACH OTHER (GFS SLOWER). LATEST 12Z MODEL
RUNS SUGGEST A DIFFERENCE OF ABOUT 6-8 HOURS WITH THE GFS SPEEDING
THINGS UP A BIT FROM ITS 06Z RUN. 12Z ECMWF DISPLAY A BIT MORE
CONSISTENCY BUT STILL SOME QUESTIONS ON ITS HANDLING OF THE S/W AND
POTENTIAL SURFACE CYCLOGENESIS JUST S-SE OF OUR REGION.
MODELS DO AGREE THAT S/W IN THE SOUTHERN STREAM WILL START OUT
FAIRLY POTENT THEN WEAKEN AS IT ENCOUNTERS INCREASING CONFLUENCE
ALOFT AS IT TRANSLATE EWD ACROSS THE DEEP SOUTH AND SE U.S LATE
WED-THU. GFS AND ECMWF SUGGEST CYCLOGENESIS OCCURRING LATE WED NIGHT
INTO THU THOUGH GFS FARTHER INLAND (OVER THE FOOTHILLS OF NC) WHILE
ECMWF FAVORS A SOLUTION CLOSER TO THE COAST. THIS WILL HAVE
IMPLICATION ON TEMPS WED AND MORE SO WED NIGHT AS WELL AS CHARACTER
OF PRECIP AS ECMWF FAVORS WIDESPREAD RAIN IN AN OVERRUNNING EVENT
WHILE GFS WOULD SUGGEST PRECIP MORE CONVECTIVE IN NATURE (HIGH
SHEAR/LOW INSTABILITY SCENARIO). STILL...APPEARS HIGHEST THREAT FOR
PRECIP ACROSS CENTRAL NC WILL OCCUR LATE WED INTO THU MORNING...WITH
MOST GUIDANCE FAVORING WED NIGHT.
FOR NOW WILL MAINTAIN PREVIOUS FORECAST OF HIGHER POPS NW VERSUS SE
WED BUT FAVOR HIGHEST POPS ACROSS THE REGION WED NIGHT RATHER THAN
WED. THUS WILL INCREASE POPS TO LIKELY ACROSS THE REGION WED NIGHT
INTO THU AM IN THE EAST. TEMPS WED-WED NIGHT HIGHLY DEPENDENT ON
EVENTUAL PASSAGE/POSITION OF THE SURFACE BOUNDARY. ECMWF WOULD
FAVOR COOLER MIN TEMPS WED NIGHT THAN CURRENTLY ADVERTISED (BY ABOUT
3-4 DEGREES). HOWEVER IF GFS MORE CORRECT...MIN TEMPS WED NIGHT MAY
BE AS MUCH AS 10 DEGREES WARMER THAN FORECAST....ESPECIALLY SE HALF.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 242 PM SUNDAY...
THIS PERIOD STARTS OUT ACTIVE THAN TRANSITIONS TO A COOL DRY WEATHER
SCENARIO FOR THE WEEKEND.
S/W AND ASSOCIATED SURFACE BOUNDARY EXPECTED TO DEPART OUR REGION
THURSDAY. GFS MAINTAINS DECENT CHANCE FOR PRECIP ACROSS THE EASTERN
HALF THROUGH THU AFTERNOON WHILE ECMWF (FASTER THAN GFS) WOULD END
THE PRECIP IN THE EAST PRIOR TO THU AFTERNOON. WILL ADVERTISE POPS
DECREASING WEST-TO EAST THU THOUGH MAINTAIN SMALL CHANCE POP IN THE
EAST UNTIL SUNSET (WORST CASE SCENARIO). EXPECT DECENT CAA IN THE
WAKE OF THE DEPARTING SYSTEM SO TEMPS THU MAY ONLY RECOVER 7-10
DEGREES FROM MORNING LOWS.
STABLE COOL CANADIAN HIGH WILL BUILD INTO AND SETTLE OVER THE SE
U.S. FRI INTO SUN. NORTHERN BRANCH OF WESTERLIES CURRENTLY EXPECTED
TO BE MORE ACTIVE COMPARED TO THE SOUTHERN STREAM SO BULK OF STORM
ACTIVITY WILL OCCUR WELL TO OUR N-NW. THUS EXPECT MAINLY DRY
CONDITIONS THU NIGHT THROUGH SUNDAY. PRESENCE OF BROAD L/W TROUGH
OVER THE REGION AND SURFACE HIGH OF CANADIAN ORIGIN BUILDING INTO
THE REGION SUPPORTS TEMPS SLIGHTLY BELOW NORMAL.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 745 PM SUNDAY...
VFR CONDITIONS EARLY TONIGHT WILL GIVE WAY TO THE LIKELY
DEVELOPMENT...IN INCREASINGLY MOIST SOUTHEASTERLY RETURN FLOW...OF
LIFR/IFR STRATUS AND/OR FOG LATE TONIGHT AND EARLY MONDAY...BEFORE
CEILINGS ONLY SLOWLY LIFT THROUGH MVFR RANGE THROUGH MONDAY
AFTERNOON.
LOOKING AHEAD: THE PATTERN OF INCREASING LOW LEVEL MOISTURE IN
RETURN FLOW AROUND OFFSHORE HIGH PRESSURE WILL RESULT IN A GOOD
CHANCE OF ADDITIONAL LOW STRATUS MONDAY NIGHT. A SLOW MOVING FRONTAL
SYSTEM WILL BRING A HIGH CHANCE OF SUB-VFR CONDITIONS...WITH PERIODS
OF RAIN...TUE NIGHT-WED NIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BADGETT
SHORT TERM...BSD/WSS
LONG TERM...WSS
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
957 PM EST SUN DEC 4 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MIGRATE OFFSHORE THROUGH MID WEEK. A COLD
FRONT WILL BRING A CHANCE OF SHOWERS WEDNESDAY INTO THURSDAY. A
LARGE AREA OF CHILLY HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE
NORTHWEST LATE IN THE WEEK AND PERSIST INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 9 PM SUNDAY...CONVERGENCE AND LIFT ALONG A COASTAL TROUGH IS
A LITTLE MORE ROBUST THAN PREVIOUSLY EXPECTED. AS A CONSEQUENCE...A
RESPECTABLE BATCH OF SHOWERS HAS DEVELOPED ALONG AND AHEAD OF THIS
FEATURE. THERE IS STILL A LARGE MOUND OF DRY AIR ABOVE A NEARLY
SATURATED LAYER THAT EXTENDS TO 4 TO 6 KFT ALONG THE COAST...
SHALLOWER INLAND. HOWEVER...GIVEN RECENT RADAR AND SURFACE PRESSURE
TRENDS...WILL OPT TO INCLUDE A SLIGHT TO SMALL CHANCE OF SHOWERS ON
AND NEAR THE COAST AND ACROSS THE WATERS...INCREASING POPS FROM E TO
W OVERNIGHT.
STRATOCUMULUS WILL CONTINUE TO PUSH INLAND FROM OFF THE WATER AS A
DEVELOPING COASTAL TROUGH DRIFTS TO THE COAST OVERNIGHT. CLOUDS WILL
AGAIN MAKE FOR AN UNEVEN TEMP DROP THROUGH TONIGHT. THESE SAME
CLOUDS ALONG WITH A MOISTENING AND INCREASING LOW LEVEL ONSHORE FLOW
WILL KEEP TEMPS ELEVATED. THEREFORE...OPTED TO GO AT OR ABOVE
HIGHEST MINIMUM TEMP GUIDANCE IN MOST CASES.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...NARROW HIGH AMPLITUDE UPPER RIDGE OFF THE COAST
ON MONDAY WHILE SURFACE HIGH CENTERED FURTHER NORTH WELL OFF COAST
OF NANTUCKET. TEMPERATURES WILL BE ABOVE NORMAL WITH HIGHS CLOSE TO
70. GUIDANCE SHOWING FAIRLY COPIOUS CLOUD COVER BUT SO FAR HAS BEEN
OVERDONE AND THUS UNDERCUT SLIGHTLY. THE SURFACE RIDGE WILL BE
SUPPRESSED TO THE SOUTH AS A BROAD BELT OF SOUTHWESTERLY FLOW AND A
SURFACE COLD FRONT IMPINGES ON THE ANTICYCLONES FROM THE NW.
BECOMING WELL ALIGNED...THESE FEATURES WILL DECELERATE AND THE
ASSOCIATED CONVERGENCE THAT MAY LEAD TO LOW RAINFALL CHANCES APPEAR
DELAYED. THE SHORT TERM PERIOD LOOKS FAIRLY RAIN-FREE. TUESDAYS
HIGHS A LITTLE WARMER WITH VALUES IN THE LOW 70S...POSSIBLY BEING
ADJUSTED AT SOME POINT DUE TO THE AFOREMENTIONED UNCERTAINTY
REGARDING CLOUD COVER.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...DISCORD BETWEEN GFS/CANADIAN/ECMWF PERTAINING TO
THE MID WEEK SYSTEM CONTINUES. AS OF 12Z THE GFS MAINTAINS ITS
SLOWER SOLUTION WHILE THE ECMWF/CANADIAN ARE FASTER...THE 12Z ECMWF
A LITTLE FASTER THAN ITS 00Z SOLUTION. ALTHOUGH TIMING REMAINS IN
QUESTION THE VARIOUS SOLUTIONS DO SUGGEST TOTAL QPF IS GOING TO BE
LIMITED. SHORTWAVE TROUGH AND SURFACE LOW PASS NORTHWEST OF THE
AREA. DEEP MOISTURE AND DYNAMICS AHEAD OF THESE FEATURES MAY BRUSH
FAR WESTERN PORTIONS OF THE ILM FORECAST AREA WED INTO THU. COLD
FRONT ASSOCIATED WITH SURFACE LOW WILL PUSH OFF THE COAST
THU...FOLLOWED BY DRIER/COOLER AIR MASS.
SURFACE HIGH GRADUALLY SHIFTS EAST THROUGH THE END OF THE WEEK WHILE
ALOFT MUCH OF THE EAST COAST REMAINS UNDER BROAD TROUGHING. LATE IN
THE PERIOD SOME OF THE MEDIUM RANGE GUIDANCE BREAKS DOWN THE UPPER
TROUGH WITH HEIGHTS STARTING TO BUILD. SHOULD THIS HAPPEN
TEMPERATURES LATE IN THE PERIOD WOULD END UP NEAR TO SLIGHTLY ABOVE
CLIMO INSTEAD OF THE CURRENTLY FORECAST BELOW CLIMO TEMPS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...MODERATE CONFIDENCE OVERNIGHT DUE TO STRATUS/IFR
POTENTIAL. CONFIDENCE INCREASES ON MONDAY...BUT CONTINUED STRATOCU
MAY PERSIST THROUGH THE DAY.
HIGH PRESSURE OFF THE NE COAST IS EXTENDING DOWN INTO THE
CAROLINAS...PRODUCING EASTERLY RETURN FLOW INTO THE ILM CWA.
GUIDANCE APPEARS TO STILL BE TOO AGGRESSIVE WITH THIS MOIST
ADVECTION. ALTHOUGH HRRR AND NAM BUFR PROFILES SUGGEST IFR
DEVELOPING OVERNIGHT...BELIEVE THIS IS OVERDONE...SO WILL CONTINUE
VFR STRATUS AS MOISTURE REMAINS TRAPPED BENEATH THE SUBSIDENCE
INVERSION. HAVE INTRODUCED SCT MVFR LEVEL STRATUS AT THE COAST...BUT
ATTM DO NOT EXPECT RESTRICTIONS. INLAND HOWEVER...THERE MAY BE SOME
FOG AND/OR STRATUS WHICH WOULD CREATE RESTRICTIONS. ALL GUIDANCE IS
SUGGESTING IFR FOG AT LBT/FLO...BUT CLOUD COVER AND AN ELEVATED LLJ
CREATE SOME PAUSE AS TO FEASIBILITY OF IFR. HAVE INCREASED VSBYS TO
REMOVE IFR FOR THIS REASON...BUT WILL MONITOR OBS AND UPDATE AS
NECESSARY. WINDS WILL BE LIGHT FROM THE EAST AOB 5 KTS.
ANY FOG/STRATUS WILL LIFT TO VFR SHORTLY AFTER SUNRISE BUT CONTINUED
MOIST ADVECTION WILL PRODUCE AMPLE STRATOCU THROUGH THE DAY.
GUIDANCE DEPICTING SOME SHOWERS IN THE AFTN...BUT AGAIN THINK LOW
LEVELS WILL NOT BECOME AS SATURATED AS GUIDANCE SUGGESTS...SO HAVE
HELD OFF ON ANY CIG RESTRICTIONS AND SHOWERS. WINDS WILL BE SE AT 5
TO 10 KTS THROUGH THE DAY.
EXTENDED OUTLOOK...LOW CONFIDENCE IN FOG TUESDAY MORNING. POSSIBLE
SHOWERS ASSOCIATED WITH A FRONTAL BOUNDARY WEDNESDAY AND THURSDAY.
VFR FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 9 PM SUNDAY...A COASTAL TROUGH WILL CONTINUE TO DRIFT W ACROSS
THE WATERS OVERNIGHT. THIS WILL ALLOW OVERNIGHT WINDS TO VEER FROM
ENE TO E OR ESE ACROSS THE OUTERMOST WATERS AND FROM NE TO ENE
ACROSS THE NEAR SHORE WATERS. THE PRESSURE GRADIENT HAS GREATLY
RELAXED FROM 24 HOURS AGO AND WIND SPEEDS SHOULD BE NO HIGHER THAN
10 TO 15 KT INTO MON MORNING. SEAS WILL BE COMPRISED OF BOTH WIND
AND SWELL WITH A 9 TO 10 SECOND EASTERLY SWELL BEING SAMPLED BY THE
OFFSHORE BUOYS. SEAS WILL GENERALLY RANGE FROM 2 TO 4 FT WITH SOME 5
FT SEAS ALONG THE OUTERMOST WATERS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...ALTHOUGH A COLD FRONT WILL APPROACH FROM THE
NORTHWEST LATE IN THE PERIOD THERE WILL BE LITTLE CHANGE OVERALL IN
WINDS AND SEAS THROUGH THE SHORT TERM. HIGH PRESSURE WELL OFF THE
NEW ENGLAND COAST INITIALLY WILL SINK TO THE SOUTH AS TUESDAY
PROGRESSES. THIS WILL LEAD TO A VERY GRADUAL VEER FROM SOUTHEASTERLY
FLOW EARLY IN THE PERIOD TO A SOUTHWESTERLY FLOW BY ITS END. ALL OF
THIS WHILE SPEEDS TEND TO HOVER AROUND 10 KT. SEAS HIGHEST OVER
NORTHERN ZONES AT AROUND 3 TO 5 FT WITH SLIGHTLY LOWER VALUES OVER
SOUTHERN ZONES.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...SOUTH TO SOUTHWEST FLOW ON WED WILL BECOME
WEST-NORTHWEST SOMETIME THU AS COLD FRONT PUSHES EAST ACROSS THE
WATERS. STILL HAVE SOME TIMING QUESTIONS AND FORECAST CONFIDENCE
REMAINS LOW. HIGH PRESSURE BUILDING IN THU NIGHT/FRI WILL RESULT IN
A MORE NORTHERLY COMPONENT TO WINDS FRO THE END OF THE PERIOD. WINDS
WILL GENERALLY BE AROUND 15 KT...THOUGH PINCHED GRADIENT WED NIGHT
INTO THU AND COLD ADVECTION POST COLD FRONT LATE THU MAY BUMP SPEEDS
CLOSER TO 15 TO 20 KT. SEAS WILL REMAIN 3 TO 5 FT THROUGH THE
PERIOD...POTENTIALLY REQUIRING A SHORT LIVED SCEC LATE WED NIGHT OR
LATE THU INTO FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RJD
SHORT TERM...MBB
LONG TERM...III
AVIATION...JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
757 PM EST SUN DEC 4 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MIGRATE OFFSHORE THROUGH MID WEEK. A COLD
FRONT WILL BRING A CHANCE OF SHOWERS WEDNESDAY INTO THURSDAY. A
LARGE AREA OF CHILLY HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE
NORTHWEST LATE IN THE WEEK AND PERSIST INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 7 PM SUNDAY...STRATOCUMULUS WILL CONTINUE TO PUSH INLAND FROM
OFF THE WATER AS A DEVELOPING COASTAL TROUGH DRIFTS TO THE COAST
OVERNIGHT. SOME VERY PATCHY LIGHT RAIN OFFSHORE MAY APPROACH THE
COAST MON MORNING AS THE TROUGH NEARS. DO NOT EXPECT MEASURABLE
RAINFALL GIVEN THE VERY DRY AIR IN THE MID LEVELS...PERHAPS A BRIEF
AND FAR BETWEEN EARLY MORNING SPRINKLE...WILL KEEP POPS BELOW
THRESHOLD.
CLOUDS WILL AGAIN MAKE FOR AN UNEVEN TEMP DROP THROUGH TONIGHT.
THESE SAME CLOUDS ALONG WITH A MOISTENING AND INCREASING LOW LEVEL
ONSHORE FLOW WILL KEEP TEMPS ELEVATED OVERNIGHT. THEREFORE...OPTED
TO GO AT OR ABOVE HIGHEST MINIMUM TEMP GUIDANCE IN MOST CASES.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...NARROW HIGH AMPLITUDE UPPER RIDGE OFF THE COAST
ON MONDAY WHILE SURFACE HIGH CENTERED FURTHER NORTH WELL OFF COAST
OF NANTUCKET. TEMPERATURES WILL BE ABOVE NORMAL WITH HIGHS CLOSE TO
70. GUIDANCE SHOWING FAIRLY COPIOUS CLOUD COVER BUT SO FAR HAS BEEN
OVERDONE AND THUS UNDERCUT SLIGHTLY. THE SURFACE RIDGE WILL BE
SUPPRESSED TO THE SOUTH AS A BROAD BELT OF SOUTHWESTERLY FLOW AND A
SURFACE COLD FRONT IMPINGES ON THE ANTICYCLONES FROM THE NW.
BECOMING WELL ALIGNED...THESE FEATURES WILL DECELERATE AND THE
ASSOCIATED CONVERGENCE THAT MAY LEAD TO LOW RAINFALL CHANCES APPEAR
DELAYED. THE SHORT TERM PERIOD LOOKS FAIRLY RAIN-FREE. TUESDAYS
HIGHS A LITTLE WARMER WITH VALUES IN THE LOW 70S...POSSIBLY BEING
ADJUSTED AT SOME POINT DUE TO THE AFOREMENTIONED UNCERTAINTY
REGARDING CLOUD COVER.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...DISCORD BETWEEN GFS/CANADIAN/ECMWF PERTAINING TO
THE MID WEEK SYSTEM CONTINUES. AS OF 12Z THE GFS MAINTAINS ITS
SLOWER SOLUTION WHILE THE ECMWF/CANADIAN ARE FASTER...THE 12Z ECMWF
A LITTLE FASTER THAN ITS 00Z SOLUTION. ALTHOUGH TIMING REMAINS IN
QUESTION THE VARIOUS SOLUTIONS DO SUGGEST TOTAL QPF IS GOING TO BE
LIMITED. SHORTWAVE TROUGH AND SURFACE LOW PASS NORTHWEST OF THE
AREA. DEEP MOISTURE AND DYNAMICS AHEAD OF THESE FEATURES MAY BRUSH
FAR WESTERN PORTIONS OF THE ILM FORECAST AREA WED INTO THU. COLD
FRONT ASSOCIATED WITH SURFACE LOW WILL PUSH OFF THE COAST
THU...FOLLOWED BY DRIER/COOLER AIR MASS.
SURFACE HIGH GRADUALLY SHIFTS EAST THROUGH THE END OF THE WEEK WHILE
ALOFT MUCH OF THE EAST COAST REMAINS UNDER BROAD TROUGHING. LATE IN
THE PERIOD SOME OF THE MEDIUM RANGE GUIDANCE BREAKS DOWN THE UPPER
TROUGH WITH HEIGHTS STARTING TO BUILD. SHOULD THIS HAPPEN
TEMPERATURES LATE IN THE PERIOD WOULD END UP NEAR TO SLIGHTLY ABOVE
CLIMO INSTEAD OF THE CURRENTLY FORECAST BELOW CLIMO TEMPS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...MODERATE CONFIDENCE OVERNIGHT DUE TO STRATUS/IFR
POTENTIAL. CONFIDENCE INCREASES ON MONDAY...BUT CONTINUED STRATOCU
MAY PERSIST THROUGH THE DAY.
HIGH PRESSURE OFF THE NE COAST IS EXTENDING DOWN INTO THE
CAROLINAS...PRODUCING EASTERLY RETURN FLOW INTO THE ILM CWA.
GUIDANCE APPEARS TO STILL BE TOO AGGRESSIVE WITH THIS MOIST
ADVECTION. ALTHOUGH HRRR AND NAM BUFR PROFILES SUGGEST IFR
DEVELOPING OVERNIGHT...BELIEVE THIS IS OVERDONE...SO WILL CONTINUE
VFR STRATUS AS MOISTURE REMAINS TRAPPED BENEATH THE SUBSIDENCE
INVERSION. HAVE INTRODUCED SCT MVFR LEVEL STRATUS AT THE COAST...BUT
ATTM DO NOT EXPECT RESTRICTIONS. INLAND HOWEVER...THERE MAY BE SOME
FOG AND/OR STRATUS WHICH WOULD CREATE RESTRICTIONS. ALL GUIDANCE IS
SUGGESTING IFR FOG AT LBT/FLO...BUT CLOUD COVER AND AN ELEVATED LLJ
CREATE SOME PAUSE AS TO FEASIBILITY OF IFR. HAVE INCREASED VSBYS TO
REMOVE IFR FOR THIS REASON...BUT WILL MONITOR OBS AND UPDATE AS
NECESSARY. WINDS WILL BE LIGHT FROM THE EAST AOB 5 KTS.
ANY FOG/STRATUS WILL LIFT TO VFR SHORTLY AFTER SUNRISE BUT CONTINUED
MOIST ADVECTION WILL PRODUCE AMPLE STRATOCU THROUGH THE DAY.
GUIDANCE DEPICTING SOME SHOWERS IN THE AFTN...BUT AGAIN THINK LOW
LEVELS WILL NOT BECOME AS SATURATED AS GUIDANCE SUGGESTS...SO HAVE
HELD OFF ON ANY CIG RESTRICTIONS AND SHOWERS. WINDS WILL BE SE AT 5
TO 10 KTS THROUGH THE DAY.
EXTENDED OUTLOOK...LOW CONFIDENCE IN FOG TUESDAY MORNING. POSSIBLE
SHOWERS ASSOCIATED WITH A FRONTAL BOUNDARY WEDNESDAY AND THURSDAY.
VFR FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 7 PM SUNDAY...A COASTAL TROUGH IS EXPECTED TO SLOWLY DRIFT W
ACROSS THE WATERS OVERNIGHT. THIS WILL ALLOW WINDS TO VEER FROM ENE
TO E OR ESE ACROSS THE OUTERMOST WATERS AND FROM NE TO ENE ACROSS
THE NEAR SHORE WATERS OVERNIGHT. THE PRESSURE GRADIENT HAS GREATLY
RELAXED FROM 24 HOURS AGO AND WIND SPEEDS SHOULD BE NO HIGHER THAN
10 TO 15 KT INTO MON MORNING. SEAS WILL BE COMPRISED OF BOTH WIND
AND SWELL WITH A 9 TO 10 SECOND EASTERLY SWELL BEING SAMPLED BY THE
OFFSHORE BUOYS. SEAS WILL GENERALLY RANGE FROM 2 TO 4 FT WITH SOME 5
FT SEAS ALONG THE OUTERMOST WATERS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...ALTHOUGH A COLD FRONT WILL APPROACH FROM THE
NORTHWEST LATE IN THE PERIOD THERE WILL BE LITTLE CHANGE OVERALL IN
WINDS AND SEAS THROUGH THE SHORT TERM. HIGH PRESSURE WELL OFF THE
NEW ENGLAND COAST INITIALLY WILL SINK TO THE SOUTH AS TUESDAY
PROGRESSES. THIS WILL LEAD TO A VERY GRADUAL VEER FROM SOUTHEASTERLY
FLOW EARLY IN THE PERIOD TO A SOUTHWESTERLY FLOW BY ITS END. ALL OF
THIS WHILE SPEEDS TEND TO HOVER AROUND 10 KT. SEAS HIGHEST OVER
NORTHERN ZONES AT AROUND 3 TO 5 FT WITH SLIGHTLY LOWER VALUES OVER
SOUTHERN ZONES.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...SOUTH TO SOUTHWEST FLOW ON WED WILL BECOME
WEST-NORTHWEST SOMETIME THU AS COLD FRONT PUSHES EAST ACROSS THE
WATERS. STILL HAVE SOME TIMING QUESTIONS AND FORECAST CONFIDENCE
REMAINS LOW. HIGH PRESSURE BUILDING IN THU NIGHT/FRI WILL RESULT IN
A MORE NORTHERLY COMPONENT TO WINDS FRO THE END OF THE PERIOD. WINDS
WILL GENERALLY BE AROUND 15 KT...THOUGH PINCHED GRADIENT WED NIGHT
INTO THU AND COLD ADVECTION POST COLD FRONT LATE THU MAY BUMP SPEEDS
CLOSER TO 15 TO 20 KT. SEAS WILL REMAIN 3 TO 5 FT THROUGH THE
PERIOD...POTENTIALLY REQUIRING A SHORT LIVED SCEC LATE WED NIGHT OR
LATE THU INTO FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RJD
SHORT TERM...MBB
LONG TERM...III
AVIATION...JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
622 PM EST SUN DEC 4 2011
.SYNOPSIS...
PARTLY CLOUDY SKIES WILL PREVAIL FOR THE NEXT COUPLE OF DAYS. A
COLD FRONT WILL BRING A CHANCE OF SHOWERS WEDNESDAY AND POSSIBLY
INTO THURSDAY. DRIER AND COOLER WEATHER IS EXPECTED TOWARD THE END
OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 3:30 PM SUNDAY...TEMPERATURES SPIKED HIGHER THAN EXPECTED
TODAY...WITH WIDESPREAD READINGS OF AROUND 70...ALTHOUGH ONSHORE
FLOW KEPT THE BEACHES IN THE MID 60S. ADJUSTED TEMPERATURE CURVE
IN THE GRIDDED DATABASE ACCORDINGLY. OTHERWISE FORECAST REMAINS ON
TRACK...NO SUBSTANTIAL CHANGES ANTICIPATED. PREVIOUS DISCUSSION
FOLLOWS:
A LIGHT NORTHEASTERLY FLOW WILL PREVAIL WITH A WEAK WEDGE-TYPE
PATTERN IN PLACE THROUGH THE PERIOD. LATEST SURFACE ANALS SHOW A
SLIGHT TROUGH JUST OFFSHORE WITH A HIGH PRESSURE RIDGE EXTENDING
SW ALONG THE APPALACHIANS. THIS PATTERN WILL PERSIST FOR THE
REMAINDER OF THE AFTERNOON AND INTO THE OVERNIGHT HOURS. FORECAST
AND ACTUAL AREA SOUNDINGS SHOW A STRONG SUBSIDENCE INVERSION AT
AROUND 5 KFT AND VERY DRY MID LEVELS WITH MOIST LOWER LEVELS.
WEDGE PATTERN TOO WEAK TO BE CONSIDERED A TYPICAL CAD
EVENT...THERE WILL BE NOT ENOUGH FORCING OR MOISTURE ALOFT FOR
MEASURABLE PRECIP...BUT IT IS POSSIBLE WE COULD SEE STRATUS
ADVANCE INLAND FROM THE COAST OVERNIGHT...PERHAPS GETTING PATCHY
MIST AT TIMES. AGAIN...SEE LITTLE CHANCE FOR ACCUMULATING
PRECIP...SO WILL KEEP POPS SILENT.
RISING HEIGHTS AND A LIGHT NORTHEASTERLY FLOW WILL KEEP
TEMPERATURES ON THE MILD SIDE...MID TO UPPER 60S FOR THE REMAINDER
OF THIS AFTERNOON...DROPPING TO THE MID TO UPPER 40S INLAND AND
LOWER 50S AT THE COAST OVERNIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...NARROW HIGH AMPLITUDE UPPER RIDGE OFF THE COAST
ON MONDAY WHILE SURFACE HIGH CENTERED FURTHER NORTH WELL OFF COAST
OF NANTUCKET. TEMPERATURES WILL BE ABOVE NORMAL WITH HIGHS CLOSE TO
70. GUIDANCE SHOWING FAIRLY COPIOUS CLOUD COVER BUT SO FAR HAS BEEN
OVERDONE AND THUS UNDERCUT SLIGHTLY. THE SURFACE RIDGE WILL BE
SUPPRESSED TO THE SOUTH AS A BROAD BELT OF SOUTHWESTERLY FLOW AND A
SURFACE COLD FRONT IMPINGES ON THE ANTICYCLONES FROM THE NW.
BECOMING WELL ALIGNED...THESE FEATURES WILL DECELERATE AND THE
ASSOCIATED CONVERGENCE THAT MAY LEAD TO LOW RAINFALL CHANCES APPEAR
DELAYED. THE SHORT TERM PERIOD LOOKS FAIRLY RAIN-FREE. TUESDAYS
HIGHS A LITTLE WARMER WITH VALUES IN THE LOW 70S...POSSIBLY BEING
ADJUSTED AT SOME POINT DUE TO THE AFOREMENTIONED UNCERTAINTY
REGARDING CLOUD COVER.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...DISCORD BETWEEN GFS/CANADIAN/ECMWF PERTAINING TO
THE MID WEEK SYSTEM CONTINUES. AS OF 12Z THE GFS MAINTAINS ITS
SLOWER SOLUTION WHILE THE ECMWF/CANADIAN ARE FASTER...THE 12Z ECMWF
A LITTLE FASTER THAN ITS 00Z SOLUTION. ALTHOUGH TIMING REMAINS IN
QUESTION THE VARIOUS SOLUTIONS DO SUGGEST TOTAL QPF IS GOING TO BE
LIMITED. SHORTWAVE TROUGH AND SURFACE LOW PASS NORTHWEST OF THE
AREA. DEEP MOISTURE AND DYNAMICS AHEAD OF THESE FEATURES MAY BRUSH
FAR WESTERN PORTIONS OF THE ILM FORECAST AREA WED INTO THU. COLD
FRONT ASSOCIATED WITH SURFACE LOW WILL PUSH OFF THE COAST
THU...FOLLOWED BY DRIER/COOLER AIR MASS.
SURFACE HIGH GRADUALLY SHIFTS EAST THROUGH THE END OF THE WEEK WHILE
ALOFT MUCH OF THE EAST COAST REMAINS UNDER BROAD TROUGHING. LATE IN
THE PERIOD SOME OF THE MEDIUM RANGE GUIDANCE BREAKS DOWN THE UPPER
TROUGH WITH HEIGHTS STARTING TO BUILD. SHOULD THIS HAPPEN
TEMPERATURES LATE IN THE PERIOD WOULD END UP NEAR TO SLIGHTLY ABOVE
CLIMO INSTEAD OF THE CURRENTLY FORECAST BELOW CLIMO TEMPS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...MODERATE CONFIDENCE OVERNIGHT DUE TO STRATUS/IFR
POTENTIAL. CONFIDENCE INCREASES ON MONDAY...BUT CONTINUED STRATOCU
MAY PERSIST THROUGH THE DAY.
HIGH PRESSURE OFF THE NE COAST IS EXTENDING DOWN INTO THE
CAROLINAS...PRODUCING EASTERLY RETURN FLOW INTO THE ILM CWA.
GUIDANCE APPEARS TO STILL BE TOO AGGRESSIVE WITH THIS MOIST
ADVECTION. ALTHOUGH HRRR AND NAM BUFR PROFILES SUGGEST IFR
DEVELOPING OVERNIGHT...BELIEVE THIS IS OVERDONE...SO WILL CONTINUE
VFR STRATUS AS MOISTURE REMAINS TRAPPED BENEATH THE SUBSIDENCE
INVERSION. HAVE INTRODUCED SCT MVFR LEVEL STRATUS AT THE COAST...BUT
ATTM DO NOT EXPECT RESTRICTIONS. INLAND HOWEVER...THERE MAY BE SOME
FOG AND/OR STRATUS WHICH WOULD CREATE RESTRICTIONS. ALL GUIDANCE IS
SUGGESTING IFR FOG AT LBT/FLO...BUT CLOUD COVER AND AN ELEVATED LLJ
CREATE SOME PAUSE AS TO FEASIBILITY OF IFR. HAVE INCREASED VSBYS TO
REMOVE IFR FOR THIS REASON...BUT WILL MONITOR OBS AND UPDATE AS
NECESSARY. WINDS WILL BE LIGHT FROM THE EAST AOB 5 KTS.
ANY FOG/STRATUS WILL LIFT TO VFR SHORTLY AFTER SUNRISE BUT CONTINUED
MOIST ADVECTION WILL PRODUCE AMPLE STRATOCU THROUGH THE DAY.
GUIDANCE DEPICTING SOME SHOWERS IN THE AFTN...BUT AGAIN THINK LOW
LEVELS WILL NOT BECOME AS SATURATED AS GUIDANCE SUGGESTS...SO HAVE
HELD OFF ON ANY CIG RESTRICTIONS AND SHOWERS. WINDS WILL BE SE AT 5
TO 10 KTS THROUGH THE DAY.
EXTENDED OUTLOOK...LOW CONFIDENCE IN FOG TUESDAY MORNING. POSSIBLE
SHOWERS ASSOCIATED WITH A FRONTAL BOUNDARY WEDNESDAY AND THURSDAY.
VFR FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3:30 PM SUNDAY...LATEST OBS SHOW 3 TO 5 FT SEAS WITH
NORTHEASTERLY WINDS OF 10 TO 15 KTS. FORECAST REMAINS ON
TRACK...NO CHANGES EXPECTED. PREVIOUS DISCUSSION FOLLOWS:
A LIGHT NORTHEASTERLY FLOW WILL VEER MORE EASTERLY OVERNIGHT AS A
WEAK TROUGH OF LOW PRESSURE SETS UP JUST OFFSHORE AND ALONG THE
COAST. WINDS WILL REMAIN IN THE 10 TO 15 KT RANGE...WITH SEAS OF 3
TO 5 FT MOST OF THE WATERS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...ALTHOUGH A COLD FRONT WILL APPROACH FROM THE
NORTHWEST LATE IN THE PERIOD THERE WILL BE LITTLE CHANGE OVERALL IN
WINDS AND SEAS THROUGH THE SHORT TERM. HIGH PRESSURE WELL OFF THE
NEW ENGLAND COAST INITIALLY WILL SINK TO THE SOUTH AS TUESDAY
PROGRESSES. THIS WILL LEAD TO A VERY GRADUAL VEER FROM SOUTHEASTERLY
FLOW EARLY IN THE PERIOD TO A SOUTHWESTERLY FLOW BY ITS END. ALL OF
THIS WHILE SPEEDS TEND TO HOVER AROUND 10 KT. SEAS HIGHEST OVER
NORTHERN ZONES AT AROUND 3 TO 5 FT WITH SLIGHTLY LOWER VALUES OVER
SOUTHERN ZONES.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...SOUTH TO SOUTHWEST FLOW ON WED WILL BECOME
WEST-NORTHWEST SOMETIME THU AS COLD FRONT PUSHES EAST ACROSS THE
WATERS. STILL HAVE SOME TIMING QUESTIONS AND FORECAST CONFIDENCE
REMAINS LOW. HIGH PRESSURE BUILDING IN THU NIGHT/FRI WILL RESULT IN
A MORE NORTHERLY COMPONENT TO WINDS FRO THE END OF THE PERIOD. WINDS
WILL GENERALLY BE AROUND 15 KT...THOUGH PINCHED GRADIENT WED NIGHT
INTO THU AND COLD ADVECTION POST COLD FRONT LATE THU MAY BUMP SPEEDS
CLOSER TO 15 TO 20 KT. SEAS WILL REMAIN 3 TO 5 FT THROUGH THE
PERIOD...POTENTIALLY REQUIRING A SHORT LIVED SCEC LATE WED NIGHT OR
LATE THU INTO FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...REK
NEAR TERM...REK
SHORT TERM...MBB
LONG TERM...III
AVIATION..JDW
MARINE...REK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
622 PM CST SUN DEC 4 2011
.UPDATE...
TEMPERATURES...WINDS AND CLOUDS.
&&
.DISCUSSION...
FLURRIES CONTINUE OVER MOST AREAS WITH A FEW REPORTS OF BLOWING
SNOW(AT KDIK AND REPORT FROM A OBSERVER AT KISN NOT CAUSING ISSUES NOW0...BUT
ALL IN ALL A WINTER WEATHER ADVISORY APPEARS APPROPRIATE FOR A
COUPLE MORE HOURS. CURRENT HEADLINE WILL CONTINUE UNTIL 8 OR 9 PM
AND PERHAPS EXTEND BEYOND MIDNIGHT OVER THE SOUTHEAST IF LIGHT
SNOW THERE CONTINUES AS RUC WOULD SUGGEST. OTHERWISE TRENDS
ADJUSTED AND SKY BUMPED UP IN THE WEST.
&&
.AVIATION...
CONDITIONS TRENDING TO MVFR WITH SOME TAF BEGINNING TO SHOW
PERIODS OF VFR. WILL CONTINUE TEMPO MVFR IN THOSE UNTIL 02Z IN THE
NORTHWEST AND WEST. MVFR AT BEST OVER CENTRAL AND EAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT
FOR NDZ001>003-009>011-017>021-031>035-040>046.
&&
$$
SHORT TERM...HW
AVIATION...HW
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
956 PM EST SUN DEC 4 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL GRADUALLY OVERSPREAD THE REGION LATE TONIGHT AND
MONDAY MORNING. FOR THE MIDDAY AND AFTERNOON HOURS ON MONDAY
RAINFALL WILL INCREASE IN COVERAGE AND INTENSITY OVER THE WEST AND
SPREAD ACROSS CENTRAL PENNSYLVANIA MONDAY NIGHT. TEMPERATURES WILL
CONTINUE WELL ABOVE AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD
FRONT BRING TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE
TUESDAY AND WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE
REGION FROM THE SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO
BRING SOME WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 9 AM MONDAY MORNING/...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF...18Z NAM AND 00Z RUC SHOWS SOME LIGHT SHOWERS PUSHING
INTO WARREN AND WRN MCKEAN COUNTY TONIGHT /AND PERHAPS ELK COUNTY
AFTER 07Z/. QPF WILL BE LIGHT AND LESS THAN 0.10 OF AN INCH
THROUGH DAYBREAK MONDAY.
THE SHOWERS WILL BE AT THE EASTERN EDGE OF A NNE/SSW RIBBON OF 1
INCH PWAT AIR. A RATHER SHARP GRADIENT TO LOWER...MEAN 925-850 MB
THETA-E AIR WILL OCCUR NEAR THE ALLEGHENY FRONT THOUGH 12Z MONDAY
WITH POPS AOB 10 PERCENT ACROSS OUR CENTRAL AND ERN ZONES.
RELATIVELY HIGHER SFC DEWPOINTS ACROSS THE SUSQ VALLEY AS SOME
PERIODS OF CLEARING WILL SUPPORT THE FORMATION OF FOG/LOW CLOUDS
ONCE AGAIN LATE TONIGHT. NUMERICAL/MOS GUIDANCE INDICATES UP TO A
SVRL HOUR PERIOD OF VSBYS BELOW 1SM AT KLNS...KMDT AND KTHV TOWARD
DAYBREAK. INCLUDED AREAS OF FOG WITH PATCHY DENSE FOG WITH THIS
LATEST GRID UPDATE - ACROSS THE MIDDLE SUSQ...AND ESP LOWER SUSQ
VALLEY LATE TONIGHT/EARLY MONDAY.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS IN MOST PLACES /WHICH WILL BE 10-15F ABOVE NORMAL...WITH
THE GREATEST DEPARTURES OCCURRING ACROSS THE MOUNTAINS/. THE
TYPICALLY COLDER SPOTS NEAR AND TO THE EAST OF THE SUSQ VALLEY
/LIKE KTHV AND KSEG/ WILL DIP INTO THE LOWER AND MID 30S WITH NEAR
CALM AIR.
&&
.SHORT TERM /9 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
A SLOW MOVING COLD FRONT WILL SPREAD SCT SHRA INTO NW PA
OVERNIGHT. HOWEVER...THE GREATEST AVIATION CONCERN TONIGHT WILL
BE THE POTENTIAL OF DENSE FOG FORMING OVER EASTERN PA. DWPT
DEPRESSIONS OF JUST A FEW DEGREES AT 01Z AND FAVORABLE CONDS FOR
ADDITIONAL RADIATIONAL COOLING SHOULD LEAD TO FOG DEVELOPING BY
MIDNIGHT AT MDT AND LNS. BULK OF LATEST SHORT RANGE MDL DATA
SUGGESTS IFR VSBYS ARE POSSIBLE LATE TONIGHT AT MDT/IPT AND LIKELY
AT LNS.
FOG OVER THE SUSQ VALLEY SHOULD DISSIPATE BY MIDDAY MONDAY. FOCUS
WILL THEN SHIFT TOWARD APPROACHING COLD FRONT...WHICH WILL SPREAD
SHRA INTO THE NW MTNS DURING THE AFTN. IFR CIGS/VSBYS APPEAR
POSSIBLE AT BFD BY MON EVENING.
OUTLOOK...
TUE...AM LOW CIGS POSSIBLE.
WED...NO SIG WX EXPECTED.
THU...RAIN/SNOWLOW CIGS POSSIBLE.
FRI...SHSN POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
842 PM EST SUN DEC 4 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL GRADUALLY OVERSPREAD THE REGION LATE TONIGHT AND
MONDAY MORNING. FOR THE MIDDAY AND AFTERNOON HOURS ON MONDAY
RAINFALL WILL INCREASE IN COVERAGE AND INTENSITY OVER THE WEST AND
SPREAD ACROSS CENTRAL PENNSYLVANIA MONDAY NIGHT. TEMPERATURES WILL
CONTINUE WELL ABOVE AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD
FRONT BRING TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE
TUESDAY AND WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE
REGION FROM THE SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO
BRING SOME WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF...18Z NAM AND 00Z RUC SHOWS SOME LIGHT SHOWERS PUSHING
INTO WARREN AND WRN MCKEAN COUNTY TONIGHT /AND PERHAPS ELK COUNTY
AFTER 07Z/. QPF WILL BE LIGHT AND LESS THAN 0.10 OF AN INCH
THROUGH DAYBREAK MONDAY.
THE SHOWERS WILL BE AT THE EASTERN EDGE OF A NNE/SSW RIBBON OF 1
INCH PWAT AIR. A RATHER SHARP GRADIENT TO LOWER...MEAN 925-850 MB
THETA-E AIR WILL OCCUR NEAR THE ALLEGHENY FRONT THOUGH 12Z MONDAY
WITH POPS AOB 10 PERCENT ACROSS OUR CENTRAL AND ERN ZONES.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS /WHICH WILL BE 10-15F ABOVE NORMAL...WITH THE GREATEST
DEPARTURES OCCURRING ACROSS THE MOUNTAINS/. A FEW TYPICALLY COLDER
SPOTS NEAR AND TO THE EAST OF THE SUSQ VALLEY WILL DIP INTO THE
MID 30S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
A SLOW MOVING COLD FRONT WILL SPREAD SCT SHRA INTO NW PA
OVERNIGHT. HOWEVER...THE GREATEST AVIATION CONCERN TONIGHT WILL
BE THE POTENTIAL OF DENSE FOG FORMING OVER EASTERN PA. DWPT
DEPRESSIONS OF JUST A FEW DEGREES AT 01Z AND FAVORABLE CONDS FOR
ADDITIONAL RADIATIONAL COOLING SHOULD LEAD TO FOG DEVELOPING BY
MIDNIGHT AT MDT AND LNS. BULK OF LATEST SHORT RANGE MDL DATA
SUGGESTS IFR VSBYS ARE POSSIBLE LATE TONIGHT AT MDT/IPT AND LIKELY
AT LNS.
FOG OVER THE SUSQ VALLEY SHOULD DISSIPATE BY MIDDAY MONDAY. FOCUS
WILL THEN SHIFT TOWARD APPROACHING COLD FRONT...WHICH WILL SPREAD
SHRA INTO THE NW MTNS DURING THE AFTN. IFR CIGS/VSBYS APPEAR
POSSIBLE AT BFD BY MON EVENING.
OUTLOOK...
TUE...AM LOW CIGS POSSIBLE.
WED...NO SIG WX EXPECTED.
THU...RAIN/SNOWLOW CIGS POSSIBLE.
FRI...SHSN POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
820 PM EST SUN DEC 4 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL OVERSPREAD TONIGHT. ON MONDAY RAINFALL WILL INCREASE
IN COVERAGE AND INTENSITY OVER THE WEST AND SPREAD ACROSS CENTRAL
PENNSYLVANIA OVERNIGHT. TEMPERATURES WILL CONTINUE WELL ABOVE
AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD FRONT BRING
TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE TUESDAY AND
WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE REGION FROM THE
SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO BRING SOME
WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF AND 21Z RUC SHOWS SOME LIGHT SHOWERS EDGING INTO WARREN
AND PERHAPS ELK/MCKEAN COUNTIES AFTER 07Z. EVEN THERE...QPF WILL
BE LIGHT AND LESS THAN 0.10 BY 12Z MONDAY.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS /WHICH WILL BE 10-15F ABOVE NORMAL...WITH THE GREATEST
DEPARTURES OCCURRING ACROSS THE MOUNTAINS/.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A SLOW MOVING COLD FRONT WILL SPREAD SCT SHRA INTO NW PA
OVERNIGHT. HOWEVER...THE GREATEST AVIATION CONCERN TONIGHT WILL
BE THE POTENTIAL OF DENSE FOG FORMING OVER EASTERN PA. DWPT
DEPRESSIONS OF JUST A FEW DEGREES AT 01Z AND FAVORABLE CONDS FOR
ADDITIONAL RADIATIONAL COOLING SHOULD LEAD TO FOG DEVELOPING BY
MIDNIGHT AT MDT AND LNS. BULK OF LATEST SHORT RANGE MDL DATA
SUGGESTS IFR VSBYS ARE POSSIBLE LATE TONIGHT AT MDT/IPT AND LIKELY
AT LNS.
FOG OVER THE SUSQ VALLEY SHOULD DISSIPATE BY MIDDAY MONDAY. FOCUS
WILL THEN SHIFT TOWARD APPROACHING COLD FRONT...WHICH WILL SPREAD
SHRA INTO THE NW MTNS DURING THE AFTN. IFR CIGS/VSBYS APPEAR
POSSIBLE AT BFD BY MON EVENING.
OUTLOOK...
TUE...AM LOW CIGS POSSIBLE.
WED...NO SIG WX EXPECTED.
THU...RAIN/SNOWLOW CIGS POSSIBLE.
FRI...SHSN POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1205 PM CST SAT DEC 3 2011
.UPDATE...
OLD STATIONARY FRONT THAT WAS OFF OUR NORTHWEST CWA EDGE...HAS
SEEPED BACK SOUTHEAST TO A CISCO...POSSUM KINGDOM LAKE...JACKSBORO
LINE WITH THE HELP OF ONGOING RAINFALL. TEMPERATURES CURRENTLY IN
THE 45-50 DEGREE RANGE BEHIND THE FRONT AT BRECKENRIDGE AND
GRAHAM AND SHOULD REMAIN COOL/WET THE REMAINDER OF THE AFTERNOON.
ELSEWHERE...SHOWERS WILL CONTINUE TO SPREAD SLOWLY EAST WITH MILD
CONDITIONS IN THE 60S TO EVEN LOWER 70S ACROSS OUR SOUTHEAST
COUNTIES WITH GUSTY SOUTHEAST WINDS 15-20 MPH.
05
&&
.AVIATION...
FOR THE 18Z TAFS...CONCERNS ARE CLOUD TRENDS AND TIMING OF
RAIN OVERNIGHT.
WARM AIR ADVECTION AHEAD OF A COLD FRONT CONTINUES ACROSS NORTH
TEXAS TODAY. THIS IS RESULTING IN WIDESPREAD RAIN AND IFR/MVFR
CONDITIONS ACROSS THE REGION. THERE IS ALSO A LARGE AREA OF LIGHT
TO MODERATE RAIN AND SHOWERS APPROACHING THE METROPLEX TAF SITES
AT THIS HOURS. EXPECT ON-AND-OFF RAIN AND SHOWERS TO CONTINUE AT
ALL TAF SITES FOR THE REMAINDER OF THE DAY.
MOST OF THE IFR CEILINGS HAVE BEEN ACROSS PARTS OF TARRANT COUNTY
AND POINTS WEST OF THERE...MOSTLY AFFECTING KFTW AND SOMETIMES
KAFW. THINK LOW END MVFR WILL CONTINUE TO AFFECT THE METROPLEX TAF
SITES WITH OCCASIONAL IFR CONDITIONS BETWEEN 800-900 FEET THROUGH
THE MID AFTERNOON HOURS. CEILINGS WILL LIKELY REMAIN BETWEEN
1000-1500 FEET FOR THE MOST PART THIS AFTERNOON. AFTER THIS BAND
OF RAIN EVENTUALLY MOVES THROUGH THIS EVENING...CEILINGS MAY
ACTUALLY IMPROVE TO VFR FOR A FEW HOURS. IT IS POSSIBLE THAT LIGHT
RAIN MAY CONTINUE INTO THE OVERNIGHT HOURS. AT KACT...MVFR
CONDITIONS WILL PREVAIL THIS AFTERNOON.
A COLD FRONT WILL ARRIVE OVERNIGHT BRINGING RAIN AND
MVFR...POSSIBLY IFR...CONDITIONS BACK TO THE REGION. BREEZY NORTH
WINDS WILL OCCUR BEHIND THE FRONT AND THE RAIN WILL CONTINUE
THROUGH THE DAY ON SUNDAY.
ONE LAST NOTE...THE MODELS ARE SLOWING DOWN THE TIMING OF FROZEN
PRECIPITATION FROM MONDAY TO MONDAY NIGHT AND CONFIDENCE REMAINS
LOW THAT WINTER PRECIP WILL AFFECT THE AIRPORTS THAT NIGHT.
FORECASTED TEMPERATURES ARE NOW WARMER THAN PREVIOUS MODEL RUNS
BUT SOME FREEZING DRIZZLE MAY AFFECT THE AIRPORTS.
82/JLD
&&
.PREV UPDATE...
.UPDATE...
ISSUING A MINOR UPDATE TO RAIN TRENDS TODAY PER CURRENT REGIONAL
RADARS AND 3KM/4KM WRF AND HRRR TRENDS. STREAMER SHOWERS IN WARM
ADVECTION REGIME LITTLE MORE NUMEROUS THAN EXPECTED ACROSS THE
EASTERN COUNTIES...WHILE MORE LINEAR BAND OF SHOWERS WITH ISOLATED
EMBEDDED THUNDER NOW ARRIVING INTO NORTHWEST COUNTIES ASSOCIATED
WITH LARGE SCALE LIFT ASSOCIATED WITH A SHORTWAVE MOVING UP INTO
OKLAHOMA.
HAVE BASICALLY TRENDED LIKELY TO CATEGORICAL POPS ACROSS THE NORTH
WITH LOWER CHANCES ACROSS THE SOUTH WHERE FORCING WILL BE WEAKER
AND RAIN MORE SCATTERED IN NATURE. RAINFALL AMOUNTS TO BE LIGHT
OVERALL WITH LESS THAN A TENTH OF AN INCH EXPECTED...HOWEVER
ISOLATED HEAVIER AMOUNTS TO BETWEEN BETWEEN A QUARTER AND HALF
INCH MAY BE POSSIBLE WITH ANY EMBEDDED THUNDERSTORMS NEAR THE RED
RIVER.
REGARDING POSSIBLE WINTER WEATHER LATE SUNDAY NIGHT THROUGH MONDAY...
12Z MODEL RUNS ARE NOW ARRIVING THIS MORNING AND A MAJORITY OF
THEM...INCLUDING THE SREF ENSEMBLE ARE SHOWING A SLOWER TREND ON
THE ARRIVAL OF THE DEEPER COLD AIR AND ANY TRANSITION TO A WINTRY
MIXTURE ON MONDAY. IT APPEARS THAT OUTSIDE OF THE NORTHWEST COUNTIES...
MANY AREAS MAY NOT SEE ANY MIXTURE OR TRANSITION UNTIL LATE IN DAY
MONDAY OR POSSIBLY EVEN MONDAY EVENING. WE WILL CONTINUE TO
ANALYZE THE NEW DATA AND MAKE ANY NECESSARY ADJUSTMENTS TO THE
FORECAST ON THE AFTERNOON PACKAGE.
05/
&&
.PREV DISCUSSION... /ISSUED 413 AM CST SAT DEC 3 2011/
LOW LEVEL WARM AIR ADVECTION WILL PREVAIL ACROSS NORTH TEXAS
TODAY AS A WARM FRONT CONTINUES TO LIFT NORTH OF THE REGION. LARGE
SCALE LIFT WILL ALSO BE ON THE INCREASE FROM WEST TO EAST TODAY AS
PIECES OF ENERGY ASSOCIATED WITH A DEEP UPPER LOW OVER THE
SOUTHWESTERN UNITED STATES EJECT NORTHEAST ACROSS THE REGION. THE
BEST RAIN CHANCES TODAY WILL BE ACROSS THE NORTHWEST SECTIONS OF
NORTH TEXAS WHERE LIFT WILL BE MAXIMIZED. SOME ISOLATED THUNDER IS
ALSO POSSIBLE TODAY DUE TO INCREASING ELEVATED INSTABILITY.
A COLD FRONT WILL MOVE SOUTHEAST ACROSS NORTH TEXAS TONIGHT AND
PROVIDE ADDITIONAL LIFT FOR RAIN AND ISOLATED THUNDERSTORMS. THE
COLD FRONT WILL BRING MUCH COOLER AIR TO THE REGION WITH LOWS
SUNDAY MORNING COOLING INTO THE 30S ACROSS THE NORTHWEST ZONES.
FOR NOW IT APPEARS THAT ALL TEMPERATURES WILL REMAIN ABOVE
FREEZING SUNDAY MORNING.
AN INTERESTING PATTERN WILL EVOLVE LATE SUNDAY INTO MONDAY WITH
COLD AIR IN PLACE AT THE SURFACE AND UPPER LEVEL LOW PRESSURE STILL
TO THE WEST/SOUTHWEST OF THE REGION. THIS WILL RESULT IN MOISTURE
RIDING UP AND OVER THE WEDGE OF COLD AIR AT THE SURFACE...THUS
PROVIDING LIFT FOR AREAS OF RAIN SUNDAY AND SUNDAY NIGHT. THE
FORECAST GETS COMPLICATED IN THE PREDAWN HOURS MONDAY MORNING AS
SURFACE TEMPERATURES COOL TO NEAR FREEZING IN SOME LOCATIONS. PREVIOUS
MODEL SOLUTIONS WERE INDICATING SUBFREEZING TEMPERATURES ACROSS
THE NORTHWEST ZONES JUST BEFORE SUNRISE MONDAY. HOWEVER...THE
LATEST MODEL SOLUTIONS ALL KEEP SURFACE TEMPERATURES ABOVE
FREEZING THROUGH MONDAY EVENING. THIS SEEMS VERY PLAUSIBLE BASED ON
CURRENT SURFACE ANALYSIS OF TEMPERATURES OVER THE CENTRAL AND HIGH
PLAINS. THEREFORE...HAVE DECIDED TO KEEP ALL TEMPERATURES ABOVE
FREEZING THROUGH MONDAY EVENING WHICH WILL ELIMINATE THE POTENTIAL
FOR FREEZING RAIN. THE GFS AND ECMWF FORECAST SOUNDINGS DO
INDICATE THAT TEMPERATURES WILL FALL BELOW FREEZING JUST ABOVE
THE SURFACE AND THAT ONLY A WEAK WARM NOSE WILL EXIST.
THEREFORE...THE POTENTIAL FOR ACCUMULATING SLEET WILL BE LOW. THE
GFS DOES INDICATE SATURATION OF THE DENDRITIC GROWTH ZONE ON
MONDAY ACROSS ABOUT THE NORTHWEST HALF OF THE REGION WHILE THE
ECMWF AND THE NAM SHOW DRYING IN THAT LAYER. IF THE GFS SOLUTION
VERIFIES THE NORTHWEST HALF OF THE REGION COULD SEE A MIX OF LIGHT
RAIN AND LIGHT SNOW CHANGE OVER TO ALL LIGHT SNOW THROUGH THE DAY.
THERE WILL BE A LOW POTENTIAL FOR VERY LIGHT ACCUMULATIONS ACROSS
THE NORTHWEST ZONES AND ALMOST NO ACCUMULATIONS FARTHER SOUTH AND
SOUTHEAST. IF THE ECMWF SOLUTION VERIFIES ONLY COLD LIGHT RAIN OR
MAYBE MIX OF LIGHT RAIN AND LIGHT SLEET OR LIGHT SNOW WILL FALL.
BOTH SOLUTION KEEP INSTABILITY ON THE LOW SIDE SO THE POTENTIAL
FOR CONVECTIVE BANDING OF PRECIP IS ALSO LOW. FOR NOW WILL SIDE A
BIT CLOSER TO THE COLDER GFS SOLUTION SINCE THE MODELS MAY HAVE
OVERDONE THE WARM UP SLIGHTLY. WE WILL HAVE TO KEEP A CLOSE EYE ON
TEMPERATURE AND MOISTURE PROFILES OVER THE NEXT 24 TO 48 HOURS AS
EVEN SLIGHT CHANGES COULD CHANGE THE FORECAST DRASTICALLY.
PRECIPITATION CHANCES SHOULD COME TO AN END MONDAY EVENING AS
ISENTROPIC DOWNGLIDE INCREASES. THE WESTERN U.S. TROUGH WILL
FINALLY MOVE ACROSS THE REGION TUESDAY AND DRY NORTHWEST TO
WESTERLY FLOW WILL SET UP ACROSS NORTH TEXAS THROUGH THE WEEKEND
AS AN UPPER TROUGH DEVELOPS OVER THE NORTHERN AND CENTRAL PLAINS.
AFTER A COLD START TO THE WEEK...TEMPERATURES WILL START TO
REBOUND BY THE MIDDLE OF THE WEEK AS LOW LEVEL MOISTURE RETURNS.
HOWEVER...A COLD FRONT WILL MOVE ACROSS THE REGION LATE THURSDAY
THROUGH FRIDAY AND COOL TEMPERATURES WELL BELOW SEASONAL NORMALS AGAIN.
THE COLD FRONT SHOULD COME THROUGH NORTH TEXAS DRY DUE TO INSUFFICIENT
MOISTURE AND LACK OF UPPER LEVEL DYNAMICS. 79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 67 42 48 37 44 / 70 70 70 80 60
WACO, TX 69 46 47 39 44 / 40 80 70 80 60
PARIS, TX 63 45 48 37 44 / 60 80 80 80 60
DENTON, TX 64 38 45 36 39 / 80 70 70 80 60
MCKINNEY, TX 67 41 48 36 41 / 70 80 70 80 60
DALLAS, TX 68 42 44 36 42 / 70 70 70 80 60
TERRELL, TX 69 44 49 38 43 / 60 70 80 80 60
CORSICANA, TX 71 47 49 39 43 / 40 80 80 80 60
TEMPLE, TX 71 48 48 39 46 / 30 80 70 70 60
MINERAL WELLS, TX 61 37 41 33 36 / 70 60 60 70 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1135 AM CST SAT DEC 3 2011
.AVIATION...
FOR THE 18Z TAFS...CONCERNS ARE CLOUD TRENDS AND TIMING OF
RAIN OVERNIGHT.
WARM AIR ADVECTION AHEAD OF A COLD FRONT CONTINUES ACROSS NORTH
TEXAS TODAY. THIS IS RESULTING IN WIDESPREAD RAIN AND IFR/MVFR
CONDITIONS ACROSS THE REGION. THERE IS ALSO A LARGE AREA OF LIGHT
TO MODERATE RAIN AND SHOWERS APPROACHING THE METROPLEX TAF SITES
AT THIS HOURS. EXPECT ON-AND-OFF RAIN AND SHOWERS TO CONTINUE AT
ALL TAF SITES FOR THE REMAINDER OF THE DAY.
MOST OF THE IFR CEILINGS HAVE BEEN ACROSS PARTS OF TARRANT COUNTY
AND POINTS WEST OF THERE...MOSTLY AFFECTING KFTW AND SOMETIMES
KAFW. THINK LOW END MVFR WILL CONTINUE TO AFFECT THE METROPLEX TAF
SITES WITH OCCASIONAL IFR CONDITIONS BETWEEN 800-900 FEET THROUGH
THE MID AFTERNOON HOURS. CEILINGS WILL LIKELY REMAIN BETWEEN
1000-1500 FEET FOR THE MOST PART THIS AFTERNOON. AFTER THIS BAND
OF RAIN EVENTUALLY MOVES THROUGH THIS EVENING...CEILINGS MAY
ACTUALLY IMPROVE TO VFR FOR A FEW HOURS. IT IS POSSIBLE THAT LIGHT
RAIN MAY CONTINUE INTO THE OVERNIGHT HOURS. AT KACT...MVFR
CONDITIONS WILL PREVAIL THIS AFTERNOON.
A COLD FRONT WILL ARRIVE OVERNIGHT BRINGING RAIN AND
MVFR...POSSIBLY IFR...CONDITIONS BACK TO THE REGION. BREEZY NORTH
WINDS WILL OCCUR BEHIND THE FRONT AND THE RAIN WILL CONTINUE
THROUGH THE DAY ON SUNDAY.
ONE LAST NOTE...THE MODELS ARE SLOWING DOWN THE TIMING OF FROZEN
PRECIPITATION FROM MONDAY TO MONDAY NIGHT AND CONFIDENCE REMAINS
LOW THAT WINTER PRECIP WILL AFFECT THE AIRPORTS THAT NIGHT.
FORECASTED TEMPERATURES ARE NOW WARMER THAN PREVIOUS MODEL RUNS
BUT SOME FREEZING DRIZZLE MAY AFFECT THE AIRPORTS.
82/JLD
&&
.UPDATE...
ISSUING A MINOR UPDATE TO RAIN TRENDS TODAY PER CURRENT REGIONAL
RADARS AND 3KM/4KM WRF AND HRRR TRENDS. STREAMER SHOWERS IN WARM
ADVECTION REGIME LITTLE MORE NUMEROUS THAN EXPECTED ACROSS THE
EASTERN COUNTIES...WHILE MORE LINEAR BAND OF SHOWERS WITH ISOLATED
EMBEDDED THUNDER NOW ARRIVING INTO NORTHWEST COUNTIES ASSOCIATED
WITH LARGE SCALE LIFT ASSOCIATED WITH A SHORTWAVE MOVING UP INTO
OKLAHOMA.
HAVE BASICALLY TRENDED LIKELY TO CATEGORICAL POPS ACROSS THE NORTH
WITH LOWER CHANCES ACROSS THE SOUTH WHERE FORCING WILL BE WEAKER
AND RAIN MORE SCATTERED IN NATURE. RAINFALL AMOUNTS TO BE LIGHT
OVERALL WITH LESS THAN A TENTH OF AN INCH EXPECTED...HOWEVER
ISOLATED HEAVIER AMOUNTS TO BETWEEN BETWEEN A QUARTER AND HALF
INCH MAY BE POSSIBLE WITH ANY EMBEDDED THUNDERSTORMS NEAR THE RED
RIVER.
REGARDING POSSIBLE WINTER WEATHER LATE SUNDAY NIGHT THROUGH MONDAY...
12Z MODEL RUNS ARE NOW ARRIVING THIS MORNING AND A MAJORITY OF
THEM...INCLUDING THE SREF ENSEMBLE ARE SHOWING A SLOWER TREND ON
THE ARRIVAL OF THE DEEPER COLD AIR AND ANY TRANSITION TO A WINTRY
MIXTURE ON MONDAY. IT APPEARS THAT OUTSIDE OF THE NORTHWEST COUNTIES...
MANY AREAS MAY NOT SEE ANY MIXTURE OR TRANSITION UNTIL LATE IN DAY
MONDAY OR POSSIBLY EVEN MONDAY EVENING. WE WILL CONTINUE TO
ANALYZE THE NEW DATA AND MAKE ANY NECESSARY ADJUSTMENTS TO THE
FORECAST ON THE AFTERNOON PACKAGE.
05/
&&
.PREV DISCUSSION... /ISSUED 413 AM CST SAT DEC 3 2011/
LOW LEVEL WARM AIR ADVECTION WILL PREVAIL ACROSS NORTH TEXAS
TODAY AS A WARM FRONT CONTINUES TO LIFT NORTH OF THE REGION. LARGE
SCALE LIFT WILL ALSO BE ON THE INCREASE FROM WEST TO EAST TODAY AS
PIECES OF ENERGY ASSOCIATED WITH A DEEP UPPER LOW OVER THE
SOUTHWESTERN UNITED STATES EJECT NORTHEAST ACROSS THE REGION. THE
BEST RAIN CHANCES TODAY WILL BE ACROSS THE NORTHWEST SECTIONS OF
NORTH TEXAS WHERE LIFT WILL BE MAXIMIZED. SOME ISOLATED THUNDER IS
ALSO POSSIBLE TODAY DUE TO INCREASING ELEVATED INSTABILITY.
A COLD FRONT WILL MOVE SOUTHEAST ACROSS NORTH TEXAS TONIGHT AND
PROVIDE ADDITIONAL LIFT FOR RAIN AND ISOLATED THUNDERSTORMS. THE
COLD FRONT WILL BRING MUCH COOLER AIR TO THE REGION WITH LOWS
SUNDAY MORNING COOLING INTO THE 30S ACROSS THE NORTHWEST ZONES.
FOR NOW IT APPEARS THAT ALL TEMPERATURES WILL REMAIN ABOVE
FREEZING SUNDAY MORNING.
AN INTERESTING PATTERN WILL EVOLVE LATE SUNDAY INTO MONDAY WITH
COLD AIR IN PLACE AT THE SURFACE AND UPPER LEVEL LOW PRESSURE STILL
TO THE WEST/SOUTHWEST OF THE REGION. THIS WILL RESULT IN MOISTURE
RIDING UP AND OVER THE WEDGE OF COLD AIR AT THE SURFACE...THUS
PROVIDING LIFT FOR AREAS OF RAIN SUNDAY AND SUNDAY NIGHT. THE
FORECAST GETS COMPLICATED IN THE PREDAWN HOURS MONDAY MORNING AS
SURFACE TEMPERATURES COOL TO NEAR FREEZING IN SOME LOCATIONS. PREVIOUS
MODEL SOLUTIONS WERE INDICATING SUBFREEZING TEMPERATURES ACROSS
THE NORTHWEST ZONES JUST BEFORE SUNRISE MONDAY. HOWEVER...THE
LATEST MODEL SOLUTIONS ALL KEEP SURFACE TEMPERATURES ABOVE
FREEZING THROUGH MONDAY EVENING. THIS SEEMS VERY PLAUSIBLE BASED ON
CURRENT SURFACE ANALYSIS OF TEMPERATURES OVER THE CENTRAL AND HIGH
PLAINS. THEREFORE...HAVE DECIDED TO KEEP ALL TEMPERATURES ABOVE
FREEZING THROUGH MONDAY EVENING WHICH WILL ELIMINATE THE POTENTIAL
FOR FREEZING RAIN. THE GFS AND ECMWF FORECAST SOUNDINGS DO
INDICATE THAT TEMPERATURES WILL FALL BELOW FREEZING JUST ABOVE
THE SURFACE AND THAT ONLY A WEAK WARM NOSE WILL EXIST.
THEREFORE...THE POTENTIAL FOR ACCUMULATING SLEET WILL BE LOW. THE
GFS DOES INDICATE SATURATION OF THE DENDRITIC GROWTH ZONE ON
MONDAY ACROSS ABOUT THE NORTHWEST HALF OF THE REGION WHILE THE
ECMWF AND THE NAM SHOW DRYING IN THAT LAYER. IF THE GFS SOLUTION
VERIFIES THE NORTHWEST HALF OF THE REGION COULD SEE A MIX OF LIGHT
RAIN AND LIGHT SNOW CHANGE OVER TO ALL LIGHT SNOW THROUGH THE DAY.
THERE WILL BE A LOW POTENTIAL FOR VERY LIGHT ACCUMULATIONS ACROSS
THE NORTHWEST ZONES AND ALMOST NO ACCUMULATIONS FARTHER SOUTH AND
SOUTHEAST. IF THE ECMWF SOLUTION VERIFIES ONLY COLD LIGHT RAIN OR
MAYBE MIX OF LIGHT RAIN AND LIGHT SLEET OR LIGHT SNOW WILL FALL.
BOTH SOLUTION KEEP INSTABILITY ON THE LOW SIDE SO THE POTENTIAL
FOR CONVECTIVE BANDING OF PRECIP IS ALSO LOW. FOR NOW WILL SIDE A
BIT CLOSER TO THE COLDER GFS SOLUTION SINCE THE MODELS MAY HAVE
OVERDONE THE WARM UP SLIGHTLY. WE WILL HAVE TO KEEP A CLOSE EYE ON
TEMPERATURE AND MOISTURE PROFILES OVER THE NEXT 24 TO 48 HOURS AS
EVEN SLIGHT CHANGES COULD CHANGE THE FORECAST DRASTICALLY.
PRECIPITATION CHANCES SHOULD COME TO AN END MONDAY EVENING AS
ISENTROPIC DOWNGLIDE INCREASES. THE WESTERN U.S. TROUGH WILL
FINALLY MOVE ACROSS THE REGION TUESDAY AND DRY NORTHWEST TO
WESTERLY FLOW WILL SET UP ACROSS NORTH TEXAS THROUGH THE WEEKEND
AS AN UPPER TROUGH DEVELOPS OVER THE NORTHERN AND CENTRAL PLAINS.
AFTER A COLD START TO THE WEEK...TEMPERATURES WILL START TO
REBOUND BY THE MIDDLE OF THE WEEK AS LOW LEVEL MOISTURE RETURNS.
HOWEVER...A COLD FRONT WILL MOVE ACROSS THE REGION LATE THURSDAY
THROUGH FRIDAY AND COOL TEMPERATURES WELL BELOW SEASONAL NORMALS AGAIN.
THE COLD FRONT SHOULD COME THROUGH NORTH TEXAS DRY DUE TO INSUFFICIENT
MOISTURE AND LACK OF UPPER LEVEL DYNAMICS. 79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 68 42 48 37 44 / 70 70 70 70 60
WACO, TX 69 46 47 39 44 / 40 80 70 70 60
PARIS, TX 66 45 48 37 44 / 60 80 80 70 60
DENTON, TX 65 38 45 36 39 / 80 70 70 70 60
MCKINNEY, TX 65 41 48 36 41 / 70 80 70 70 60
DALLAS, TX 66 42 44 36 42 / 70 70 70 70 60
TERRELL, TX 67 44 49 38 43 / 60 70 80 70 60
CORSICANA, TX 70 47 49 39 43 / 40 80 80 70 60
TEMPLE, TX 71 48 48 39 46 / 30 80 70 70 60
MINERAL WELLS, TX 65 37 41 33 36 / 70 60 60 70 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1020 AM CST SAT DEC 3 2011
.UPDATE...
ISSUING A MINOR UPDATE TO RAIN TRENDS TODAY PER CURRENT REGIONAL
RADARS AND 3KM/4KM WRF AND HRRR TRENDS. STREAMER SHOWERS IN WARM
ADVECTION REGIME LITTLE MORE NUMEROUS THAN EXPECTED ACROSS THE
EASTERN COUNTIES...WHILE MORE LINEAR BAND OF SHOWERS WITH ISOLATED
EMBEDDED THUNDER NOW ARRIVING INTO NORTHWEST COUNTIES ASSOCIATED
WITH LARGE SCALE LIFT ASSOCIATED WITH A SHORTWAVE MOVING UP INTO
OKLAHOMA.
HAVE BASICALLY TRENDED LIKELY TO CATEGORICAL POPS ACROSS THE NORTH
WITH LOWER CHANCES ACROSS THE SOUTH WHERE FORCING WILL BE WEAKER
AND RAIN MORE SCATTERED IN NATURE. RAINFALL AMOUNTS TO BE LIGHT
OVERALL WITH LESS THAN A TENTH OF AN INCH EXPECTED...HOWEVER
ISOLATED HEAVIER AMOUNTS TO BETWEEN BETWEEN A QUARTER AND HALF
INCH MAY BE POSSIBLE WITH ANY EMBEDDED THUNDERSTORMS NEAR THE RED
RIVER.
REGARDING POSSIBLE WINTER WEATHER LATE SUNDAY NIGHT THROUGH MONDAY...
12Z MODEL RUNS ARE NOW ARRIVING THIS MORNING AND A MAJORITY OF
THEM...INCLUDING THE SREF ENSEMBLE ARE SHOWING A SLOWER TREND ON
THE ARRIVAL OF THE DEEPER COLD AIR AND ANY TRANSITION TO A WINTRY
MIXTURE ON MONDAY. IT APPEARS THAT OUTSIDE OF THE NORTHWEST COUNTIES...
MANY AREAS MAY NOT SEE ANY MIXTURE OR TRANSITION UNTIL LATE IN DAY
MONDAY OR POSSIBLY EVEN MONDAY EVENING. WE WILL CONTINUE TO
ANALYZE THE NEW DATA AND MAKE ANY NECESSARY ADJUSTMENTS TO THE
FORECAST ON THE AFTERNOON PACKAGE.
05/
&&
.AVIATION UPDATE...
MOST OF THE RAIN THIS MORNING HAS NOW MOVED EAST OF THE TAF
TERMINALS BUT SOME DRIZZLE OR LIGHT RAIN WILL CONTINUE THROUGH AT
LEAST THE MORNING HOURS. IFR CEILINGS ARE BEGINNING TO SPREAD
ACROSS TARRANT COUNTY...ALREADY AFFECTING KFTW...AND LIKELY MOVING
INTO THE REMAINING METROPLEX TAF SITES IN THE NEXT HOUR.
HOWEVER...THE CEILINGS ARE VARYING FROM 800-1300 FT. WILL PREVAIL
OVC010 AND TEMPO FOR LOWER CEILINGS EXPECTING THAT THE CEILINGS
WILL VARY AT TIMES. THE SAME TRENDS ARE EXPECTED AT KACT WITH
SITES TO THE WEST OF THE AIRPORT ALREADY REPORTING IFR CONDITIONS.
82/JLD
.../PREVIOUS AVIATION DISCUSSION/...
LOCAL 88D RADAR SHOWING ISENTROPIC PROCESS IS UNDERWAY FOR THE MORNING
WITH SCATTERED SHOWERS DEVELOPING AND SPREADING NORTHEAST RAPIDLY
ACROSS NORTH TEXAS. THIS PROCESS SHOULD CONTINUE THROUGH MIDDAY
WITH A POTENTIAL FOR ISOLATED THUNDER LATER THIS AFTERNOON. THERE
SHOULD BE A LULL IN THE PRECIPITATION THIS EVENING AS LIFT EXITS
THE REGION. A STRONG COLD FRONT WILL MOVE THROUGH THE TAF SITES
LATER TONIGHT WITH RAIN GEARING UP AGAIN DUE TO A COMBINATION OF
FRONTAL AND SYNOPTIC LIFT.
WILL KEEP CIGS MVFR THROUGH MOST OF THE DAY WITH VFR CIGS ABOVE
5 KFT BETWEEN 03Z AND 09Z WHILE UPPER SUPPORT MOVES NORTHEAST. THE
NEXT BATCH OF PRECIPITATION IS EXPECTED TO DEVELOP LATE TONIGHT AND
CONTINUE THROUGH MIDDAY MONDAY.
A TRANSITION TO A LIGHT RAIN LIGHT SNOW MIX IS EXPECTED ACROSS
THE METROPLEX MONDAY FROM MID-MORNING ON...BUT ONLY A LIGHT
ACCUMULATION SNOW IS EXPECTED ON ELEVATED SURFACES. CONFIDENCE IN
THE CURRENT LIGHT SNOW FORECAST IS MODERATE. 75
82
&&
.PREV DISCUSSION... /ISSUED 413 AM CST SAT DEC 3 2011/
LOW LEVEL WARM AIR ADVECTION WILL PREVAIL ACROSS NORTH TEXAS
TODAY AS A WARM FRONT CONTINUES TO LIFT NORTH OF THE REGION. LARGE
SCALE LIFT WILL ALSO BE ON THE INCREASE FROM WEST TO EAST TODAY AS
PIECES OF ENERGY ASSOCIATED WITH A DEEP UPPER LOW OVER THE
SOUTHWESTERN UNITED STATES EJECT NORTHEAST ACROSS THE REGION. THE
BEST RAIN CHANCES TODAY WILL BE ACROSS THE NORTHWEST SECTIONS OF
NORTH TEXAS WHERE LIFT WILL BE MAXIMIZED. SOME ISOLATED THUNDER IS
ALSO POSSIBLE TODAY DUE TO INCREASING ELEVATED INSTABILITY.
A COLD FRONT WILL MOVE SOUTHEAST ACROSS NORTH TEXAS TONIGHT AND
PROVIDE ADDITIONAL LIFT FOR RAIN AND ISOLATED THUNDERSTORMS. THE
COLD FRONT WILL BRING MUCH COOLER AIR TO THE REGION WITH LOWS
SUNDAY MORNING COOLING INTO THE 30S ACROSS THE NORTHWEST ZONES.
FOR NOW IT APPEARS THAT ALL TEMPERATURES WILL REMAIN ABOVE
FREEZING SUNDAY MORNING.
AN INTERESTING PATTERN WILL EVOLVE LATE SUNDAY INTO MONDAY WITH
COLD AIR IN PLACE AT THE SURFACE AND UPPER LEVEL LOW PRESSURE STILL
TO THE WEST/SOUTHWEST OF THE REGION. THIS WILL RESULT IN MOISTURE
RIDING UP AND OVER THE WEDGE OF COLD AIR AT THE SURFACE...THUS
PROVIDING LIFT FOR AREAS OF RAIN SUNDAY AND SUNDAY NIGHT. THE
FORECAST GETS COMPLICATED IN THE PREDAWN HOURS MONDAY MORNING AS
SURFACE TEMPERATURES COOL TO NEAR FREEZING IN SOME LOCATIONS. PREVIOUS
MODEL SOLUTIONS WERE INDICATING SUBFREEZING TEMPERATURES ACROSS
THE NORTHWEST ZONES JUST BEFORE SUNRISE MONDAY. HOWEVER...THE
LATEST MODEL SOLUTIONS ALL KEEP SURFACE TEMPERATURES ABOVE
FREEZING THROUGH MONDAY EVENING. THIS SEEMS VERY PLAUSIBLE BASED ON
CURRENT SURFACE ANALYSIS OF TEMPERATURES OVER THE CENTRAL AND HIGH
PLAINS. THEREFORE...HAVE DECIDED TO KEEP ALL TEMPERATURES ABOVE
FREEZING THROUGH MONDAY EVENING WHICH WILL ELIMINATE THE POTENTIAL
FOR FREEZING RAIN. THE GFS AND ECMWF FORECAST SOUNDINGS DO
INDICATE THAT TEMPERATURES WILL FALL BELOW FREEZING JUST ABOVE
THE SURFACE AND THAT ONLY A WEAK WARM NOSE WILL EXIST.
THEREFORE...THE POTENTIAL FOR ACCUMULATING SLEET WILL BE LOW. THE
GFS DOES INDICATE SATURATION OF THE DENDRITIC GROWTH ZONE ON
MONDAY ACROSS ABOUT THE NORTHWEST HALF OF THE REGION WHILE THE
ECMWF AND THE NAM SHOW DRYING IN THAT LAYER. IF THE GFS SOLUTION
VERIFIES THE NORTHWEST HALF OF THE REGION COULD SEE A MIX OF LIGHT
RAIN AND LIGHT SNOW CHANGE OVER TO ALL LIGHT SNOW THROUGH THE DAY.
THERE WILL BE A LOW POTENTIAL FOR VERY LIGHT ACCUMULATIONS ACROSS
THE NORTHWEST ZONES AND ALMOST NO ACCUMULATIONS FARTHER SOUTH AND
SOUTHEAST. IF THE ECMWF SOLUTION VERIFIES ONLY COLD LIGHT RAIN OR
MAYBE MIX OF LIGHT RAIN AND LIGHT SLEET OR LIGHT SNOW WILL FALL.
BOTH SOLUTION KEEP INSTABILITY ON THE LOW SIDE SO THE POTENTIAL
FOR CONVECTIVE BANDING OF PRECIP IS ALSO LOW. FOR NOW WILL SIDE A
BIT CLOSER TO THE COLDER GFS SOLUTION SINCE THE MODELS MAY HAVE
OVERDONE THE WARM UP SLIGHTLY. WE WILL HAVE TO KEEP A CLOSE EYE ON
TEMPERATURE AND MOISTURE PROFILES OVER THE NEXT 24 TO 48 HOURS AS
EVEN SLIGHT CHANGES COULD CHANGE THE FORECAST DRASTICALLY.
PRECIPITATION CHANCES SHOULD COME TO AN END MONDAY EVENING AS
ISENTROPIC DOWNGLIDE INCREASES. THE WESTERN U.S. TROUGH WILL
FINALLY MOVE ACROSS THE REGION TUESDAY AND DRY NORTHWEST TO
WESTERLY FLOW WILL SET UP ACROSS NORTH TEXAS THROUGH THE WEEKEND
AS AN UPPER TROUGH DEVELOPS OVER THE NORTHERN AND CENTRAL PLAINS.
AFTER A COLD START TO THE WEEK...TEMPERATURES WILL START TO
REBOUND BY THE MIDDLE OF THE WEEK AS LOW LEVEL MOISTURE RETURNS.
HOWEVER...A COLD FRONT WILL MOVE ACROSS THE REGION LATE THURSDAY
THROUGH FRIDAY AND COOL TEMPERATURES WELL BELOW SEASONAL NORMALS AGAIN.
THE COLD FRONT SHOULD COME THROUGH NORTH TEXAS DRY DUE TO INSUFFICIENT
MOISTURE AND LACK OF UPPER LEVEL DYNAMICS. 79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 68 42 48 37 44 / 70 70 70 70 60
WACO, TX 69 46 47 39 44 / 40 80 70 70 60
PARIS, TX 66 45 48 37 44 / 60 80 80 70 60
DENTON, TX 65 38 45 36 39 / 80 70 70 70 60
MCKINNEY, TX 65 41 48 36 41 / 70 80 70 70 60
DALLAS, TX 66 42 44 36 42 / 70 70 70 70 60
TERRELL, TX 67 44 49 38 43 / 60 70 80 70 60
CORSICANA, TX 70 47 49 39 43 / 40 80 80 70 60
TEMPLE, TX 71 48 48 39 46 / 30 80 70 70 60
MINERAL WELLS, TX 65 37 41 33 36 / 70 60 60 70 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/05
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
741 PM CST SUN DEC 4 2011
.UPDATED...FREEZING DRIZZLE APPEARS TO BE MORE WIDESPREAD OVER
WEST CENTRAL WISCONSIN WITH SOME MID LEVEL DRYING WORKING
SOUTHWARD. MOIST CYCLONIC FLOW OVER EASTERN WISCONSIN WOULD
DIMINISH THREAT. SOME OBSERVATIONS OVER CENTRAL WISCONSIN WERE
REPORTING SOME FLURRIES AND LIGHT MIX SO WILL ADD A SMALL MENTION
TO THE FORECAST IN THE AREA. NOGROUND TRUTH SO FAR. LESS OF A
THREAT OF ZL EAST OF AUW WITH SURFACE TEMPS STILL ABOVE FREEZING.
TDH
&&
.PREV DISCUSSION...ISSUED AT 535 PM CST SUN DEC 4 2011...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DOUBLE
BARRELED LOW PRESSURE MOVING ACROSS THE ONTARIO-QUEBEC BORDER AND
THE STRAITS OF MACKINAC...AND A COLD FRONT STRETCHING FROM NORTHERN
LOWER MICHIGAN TO THE SOUTHERN MISSISSIPPI VALLEY. WITH NORTHWEST
FLOW IN PLACE AND DELTA T/S INCREASING TO 14C...CLOUD COVER HAS BEEN
STUBBORN TO DISSIPATE THOUGH PRECIP HAS EXITED TO THE NORTHEAST BY
MIDDAY. A SURFACE TROUGH IS TRYING TO DEVELOP OVER NORTHEAST AND CENTRAL
WISCONSIN THIS AFTERNOON AND A FEW SNOW SHOWERS/FLURRIES HAVE
DEVELOPED OVER THE PAST HOUR. SOME CLEARING NOTED OVER NORTHERN
MINNESOTA WHERE DEWPOINTS HAVE FALLEN TO THE LOWER TEENS. WITH
NORTHERLY FLOW IN PLACE OVER THE NEXT 24 HOURS...SMALL PRECIP
CHANCES AND CLOUD TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT... AS HIGH PRESSURE BUILDS OVER THE NORTHERN PLAINS...WEAK
CYCLONIC FLOW WILL LINGER ACROSS THE REGION. LOW LEVEL FLOW WILL
VEER FROM THE NORTHWEST TO THE NORTH...WHICH WILL KEEP MOISTURE
STREAMING OFF LAKE SUPERIOR. AS A RESULT...SCT LAKE EFFECT SNOW
SHOWERS WILL PREVAIL OVER THE SNOW BELT OF N-C WISCONSIN FOR THE
ENTIRE NIGHT. FARTHER SOUTH...A WEAK SURFACE TROUGH WILL MOVE SOUTH
OVER CENTRAL WISCONSIN THIS EVENING. MOISTURE DEPTH WILL EXTEND
BEYOND 800MB AND -10C...SO IT SEEMS PLAUSIBLE THAT FLURRIES OR VERY
LIGHT SNOW SHOWERS ARE POSSIBLE ALONG THE TROUGH. HAVE ADDED
SLIGHTLY MORE TEMPORAL RESOLUTION TO ACCOUNT FOR THIS.
OTHERWISE...DO NOT SEE MUCH OF AN OPPORTUNITY FOR CLEARING...EXCEPT
IN THE DOWN SLOPING REGIONS OF NORTHEAST WISCONSIN WHERE SOME HOLES
MAY DEVELOP...ESPECIALLY LATE TONIGHT. LOWS IN THE UPPER TEENS
NORTH TO UPPER 20S SOUTHEAST.
MONDAY...ONLY SOME SUBTLE CHANGES HEADING INTO MONDAY. SHORTWAVE
ENERGY OVER THE PLAINS WILL LIFT TO THE NORTHEAST OVER NW
WISCONSIN...BUT WITH VERY LITTLE IMPACT ON OUR WEATHER. WILL
CONTINUE TO HAVE NORTHERLY FLOW TOMORROW WITH SOME MINOR COLD
ADVECTION THAT WILL DROP 850MB TEMPS IN THE NEGATIVE LOW TO MID
TEENS. LIGHT LAKE EFFECT SNOW SHOWERS WILL PREVAIL OVER THE SNOW
BELT OF N-C WISCONSIN...WHILE MOSTLY CLOUDY CONDITIONS WILL BE THE
RULE ELSEWHERE. HIGHS IN THE MIDDLE 20S NORTH TO MIDDLE 30S
SOUTHEAST.
LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...THE MAIN FCST
CONCERN IS THE ARRIVAL OF COLDER ARCTIC AIR LATE IN THE NEXT WORK
WEEK.
A STRONG UPPER RIDGE WILL COVER THE EASTERN PACIFIC...SOUTHWEST
CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...WITH A
POSITIVELY-TILTED UPPER TROF MOVG OUT OF THE NORTHERN PLAINS INTO
THE WESTERN GREAT LAKES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON MONDAY NIGHT AND TUESDAY...BUT WITH A SFC RIDGE OF
HIGH PRESSURE IN PLACE...EXPECT MINIMAL IMPACT ON OUR WEATHER.
SHORT-WAVE ENERGY TOPPING THE WESTERN RIDGE AND DIVING INTO THE
NORTHERN PLAINS WILL HELP TO CARVE A BROAD TROF OVER THE CENTRAL
U.S. BY THURSDAY. A SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN
WI ON THURSDAY...WITH H8 TEMPS PLUMMETING TO AROUND -20 C LATE
THURSDAY NIGHT INTO FRIDAY. THIS WILL LEAD TO OUR COLDEST
TEMPERATURES SO FAR THIS SEASON. THE COLD SNAP WILL BE BRIEF...
AS SOUTHWEST WINDS DEVELOP IN THE WAKE OF THE RETREATING ARCTIC
HIGH OVER THE WEEKEND.
A LARGE RIDGE OF HIGH PRESSURE WILL BUILD INTO NW WI ON MONDAY
NIGHT...THEN MOVE THROUGH GRB CWA ON TUESDAY. LINGERING LAKE-EFFECT
SNOW SHOWERS OVER NC WI SHOULD COME TO AN END AS THE RIDGE AXIS
ARRIVES ON TUESDAY.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING ON THURSDAY.
THE ECMWF HAS BACKED OFF ON THE POTENTIAL FOR SNOW ALONG THE
ARCTIC FRONT ON THU NGT/FRI...AND IS FOCUSING FARTHER SE...FROM
SOUTHERN WI INTO LOWER MICHIGAN. WILL NEED TO KEEP AN EYE ON THIS
OVER THE NEXT FEW DAYS TO SEE IF THIS TREND WILL HOLD. CONFIDENCE
IS FAIRLY HIGH FOR THE ARRIVAL OF MUCH COLDER TEMPERATURES LATE IN
THE WORK WEEK...ALTHOUGH THE COLD IS EXPECTED TO BE SHORT-LIVED.
A WARM FRONT IS EXPECTED TO ARRIVE ON SUNDAY...WITH TEMPERATURES
CLIMBING BACK TO ABOVE NORMAL.
DESPITE THE PRESENCE OF A COLD AIR MASS FROM WEDNESDAY THROUGH
SATURDAY...WIND TRAJECTORIES WILL NOT BE FAVORABLE FOR LK-EFFECT
SNOW.
&&
.AVIATION...A SUBTLE SURFACE TROUGH DROPPING OVER CENTRAL AND EAST
CENTRAL WISCONSIN THIS EVENING WILL BE MARKED WITH A FEW FLURRIES
ALONG WITH A SHIFT OF WINDS FROM WEST TO NORTH. OTHERWISE CYCLONIC
FLOW TONIGHT INTO MONDAY WILL CONTINUE TO SUPPORT MAINLY MVFR
CIGS.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
649 PM CST SUN DEC 4 2011
.SHORT TERM...TONIGHT
648 PM CST SUN DEC 4 2011
88-D RADAR IMAGERY CONTINUED TO SHOW AREAS OF LIGHT PCPN ACROSS
WESTERN PORTIONS OF WI...AND JUST WEST OF THE MISSISSIPPI RIVER.
LAW ENFORCEMENT...SPOTTER REPORTS...AND SFC OBS ALL INDICATE THAT
MUCH OF THIS WAS LIGHT FREEZING DRIZZLE. HAVE ISSUED A FREEZING
RAIN ADVISORY...FOR THE FREEZING DRIZZLE...UNTIL MIDNIGHT TO
ACCOUNT FOR THE LIGHT ICING THREAT.
ISENTROPIC UPGLIDE THROUGH LOW SATURATION //STRATUS// WAS THE MAIN
CULPRIT FOR THE PCPN. A LACK OF ICE IN THE CLOUDS HAS ALLOWED IT
TO FALL AS FREEZING DRIZZLE RATHER THAN FLURRIES OR LIGHT SNOW.
STILL EXPECT THOSE TO BE MIXED IN...WITH BETTER CHANCES FOR LIGHT
FROZEN PCPN FARTHER EAST. IT DOES APPEAR THAT ICE WILL BE MORE
LIKELY WITHIN THE CLOUDS OVERNIGHT...SO ONLY RAN THE ADVISORY
UNTIL MIDNIGHT. OBVIOUSLY...THIS WILL HAVE TO BE MONITORED
CLOSELY.
.LONG TERM...THURSDAY THROUGH SUNDAY
255 PM CST SUN DEC 4 2011
A GENERAL WEST TO NORTHWEST FLOW WILL CONTINUE THROUGH
SATURDAY...WITH BROAD RIDGING AT THE SURFACE. THIS WILL KEEP THE
WEATHER RATHER TRANQUIL WILL TEMPERATURES REMAINING SLIGHTLY BELOW
NORMAL. BY SATURDAY NIGHT AND SUNDAY...A SURFACE LOW LOOKS TO TRACK
ALONG THE CANADIAN BORDER...WITH THE LOW LEVEL FLOW BECOMING MORE
SOUTHERLY. 850MB TEMPERATURES DO WARM IN THE WARM ADVECTION ZONE
AHEAD OF THE ASSOCIATED COLD FRONT...TO NEAR ZERO CELSIUS AND THUS
TEMPERATURES WILL WARM INTO THE MIDDLE 30S BY SUNDAY AFTERNOON.
&&
.AVIATION...
545 PM CST SUN DEC 4 2011
LATEST SATELLITE AND SFC OBS CONTINUE TO SHOW A EXTENSIVE DECK OF
MVFR STRATUS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY EARLY THIS
EVENING...WHILE WATER VAPOR INDICATED AN UPPER LEVEL SHORTWAVE
TROUGH WORKING ACROSS THE REGION. RUC13 AND BUFKIT SOUNDINGS SHOW
SOME LIFT THROUGH THE LOW SATURATION...AND THIS COULD RESULT IN SOME
-SN/FLURRIES. SOME HINTS THAT THE CLOUDS COULD LOSE THEIR
ICE...WHICH WOULD MAKE FZDZ MORE FAVORABLE THAN -SN. AS INDICATED IN
PREVIOUS DISCUSSIONS...CONFIDENCE NOT HIGH ENOUGH TO ADD TO TAFS. IN
ADDITION...THE -SN/FLURRY CHANCES WILL LIKELY HOLD EAST OF THE AREA.
MESO MODELS FAVOR CLEARING THE CIGS FROM WEST TO EAST
OVERNIGHT...MORE SO FOR KRST THAN KLSE. MID LEVEL CLOUDS WOULD
RETURN MONDAY AFTERNOON AHEAD OF ANOTHER UPPER LEVEL SHORTWAVE. NOT
SOLD ON THE CLEARING FOR KLSE YET...ALTHOUGH IMPROVEMENT INTO VFR
MON AFTERNOON LOOKS LIKELY. BETTER CHANCES TO GO SCT AT KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
638 PM CST SUN DEC 4 2011
WI...FREEZING RAIN ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ032>034-
041>043-053.
MN...FREEZING RAIN ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ079-088-
096.
IA...NONE.
&&
$$
SHORT TERM... RABERDING
LONG TERM.... RABERDING
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
545 PM CST SUN DEC 4 2011
.SHORT TERM...TONIGHT
545 PM CST SUN DEC 4 2011
LATEST 88-D RADAR IMAGERY WAS SHOWING SOME AREAS OF LIGHT PCPN
DEVELOPING ACROSS WESTERN WI...IN RESPONSE TO LOW LEVEL MOISTURE AND
ISENTROPIC UPGLIDE. WHILE MUCH OF THIS WILL LIKELY BE FLURRIES OR
LIGHT SNOW...BUFKIT SOUNDING AND RUC13 X-SECTIONS SUGGEST THAT ICE
IN THE CLOUD WILL BE AN ISSUE FOR WESTERN WI. WITHOUT ICE...FREEZING
DRIZZLE COULD BECOME A CONCERN...AND SPOTTERS HAVE INDICATED THAT
SOME OF THIS...ALTHOUGH VERY...VERY LIGHT IS OCCURING. THIS TREND
COULD CONTINUE THIS EVENING...AND IF INTENSITY WOULD
INCREASE...THERE WOULD BE THE THREAT FOR SOME ICING ON
ROADWAYS/SIDEWALKS. HAVE UPDATED FORECAST TO REFLECT THE FREEZING
PCPN CHANCES...AND HAVE ISSUED A SPECIAL WEATHER STATEMENT. IF THE
FREEZING PCPN WOULD BECOME MORE WIDESPREAD/HEAVY...AN ADVISORY COULD
BE NEEDED.
.LONG TERM...THURSDAY THROUGH SUNDAY
255 PM CST SUN DEC 4 2011
A GENERAL WEST TO NORTHWEST FLOW WILL CONTINUE THROUGH
SATURDAY...WITH BROAD RIDGING AT THE SURFACE. THIS WILL KEEP THE
WEATHER RATHER TRANQUIL WILL TEMPERATURES REMAINING SLIGHTLY BELOW
NORMAL. BY SATURDAY NIGHT AND SUNDAY...A SURFACE LOW LOOKS TO TRACK
ALONG THE CANADIAN BORDER...WITH THE LOW LEVEL FLOW BECOMING MORE
SOUTHERLY. 850MB TEMPERATURES DO WARM IN THE WARM ADVECTION ZONE
AHEAD OF THE ASSOCIATED COLD FRONT...TO NEAR ZERO CELSIUS AND THUS
TEMPERATURES WILL WARM INTO THE MIDDLE 30S BY SUNDAY AFTERNOON.
&&
.AVIATION...
545 PM CST SUN DEC 4 2011
LATEST SATELLITE AND SFC OBS CONTINUE TO SHOW A EXTENSIVE DECK OF
MVFR STRATUS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY EARLY THIS
EVENING...WHILE WATER VAPOR INDICATED AN UPPER LEVEL SHORTWAVE
TROUGH WORKING ACROSS THE REGION. RUC13 AND BUFKIT SOUNDINGS SHOW
SOME LIFT THROUGH THE LOW SATURATION...AND THIS COULD RESULT IN SOME
-SN/FLURRIES. SOME HINTS THAT THE CLOUDS COULD LOSE THEIR
ICE...WHICH WOULD MAKE FZDZ MORE FAVORABLE THAN -SN. AS INDICATED IN
PREVIOUS DISCUSSIONS...CONFIDENCE NOT HIGH ENOUGH TO ADD TO TAFS. IN
ADDITION...THE -SN/FLURRY CHANCES WILL LIKELY HOLD EAST OF THE AREA.
MESO MODELS FAVOR CLEARING THE CIGS FROM WEST TO EAST
OVERNIGHT...MORE SO FOR KRST THAN KLSE. MID LEVEL CLOUDS WOULD
RETURN MONDAY AFTERNOON AHEAD OF ANOTHER UPPER LEVEL SHORTWAVE. NOT
SOLD ON THE CLEARING FOR KLSE YET...ALTHOUGH IMPROVEMENT INTO VFR
MON AFTERNOON LOOKS LIKELY. BETTER CHANCES TO GO SCT AT KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
255 PM CST SUN DEC 4 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RABERDING
LONG TERM.... RABERDING
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
535 PM CST SUN DEC 4 2011
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DOUBLE
BARRELED LOW PRESSURE MOVING ACROSS THE ONTARIO-QUEBEC BORDER AND
THE STRAITS OF MACKINAC...AND A COLD FRONT STRETCHING FROM NORTHERN
LOWER MICHIGAN TO THE SOUTHERN MISSISSIPPI VALLEY. WITH NORTHWEST
FLOW IN PLACE AND DELTA T/S INCREASING TO 14C...CLOUD COVER HAS BEEN
STUBBORN TO DISSIPATE THOUGH PRECIP HAS EXITED TO THE NORTHEAST BY
MIDDAY. A SURFACE TROUGH IS TRYING TO DEVELOP OVER NORTHEAST AND CENTRAL
WISCONSIN THIS AFTERNOON AND A FEW SNOW SHOWERS/FLURRIES HAVE
DEVELOPED OVER THE PAST HOUR. SOME CLEARING NOTED OVER NORTHERN
MINNESOTA WHERE DEWPOINTS HAVE FALLEN TO THE LOWER TEENS. WITH
NORTHERLY FLOW IN PLACE OVER THE NEXT 24 HOURS...SMALL PRECIP
CHANCES AND CLOUD TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT... AS HIGH PRESSURE BUILDS OVER THE NORTHERN PLAINS...WEAK
CYCLONIC FLOW WILL LINGER ACROSS THE REGION. LOW LEVEL FLOW WILL
VEER FROM THE NORTHWEST TO THE NORTH...WHICH WILL KEEP MOISTURE
STREAMING OFF LAKE SUPERIOR. AS A RESULT...SCT LAKE EFFECT SNOW
SHOWERS WILL PREVAIL OVER THE SNOW BELT OF N-C WISCONSIN FOR THE
ENTIRE NIGHT. FARTHER SOUTH...A WEAK SURFACE TROUGH WILL MOVE SOUTH
OVER CENTRAL WISCONSIN THIS EVENING. MOISTURE DEPTH WILL EXTEND
BEYOND 800MB AND -10C...SO IT SEEMS PLAUSIBLE THAT FLURRIES OR VERY
LIGHT SNOW SHOWERS ARE POSSIBLE ALONG THE TROUGH. HAVE ADDED
SLIGHTLY MORE TEMPORAL RESOLUTION TO ACCOUNT FOR THIS.
OTHERWISE...DO NOT SEE MUCH OF AN OPPORTUNITY FOR CLEARING...EXCEPT
IN THE DOWN SLOPING REGIONS OF NORTHEAST WISCONSIN WHERE SOME HOLES
MAY DEVELOP...ESPECIALLY LATE TONIGHT. LOWS IN THE UPPER TEENS
NORTH TO UPPER 20S SOUTHEAST.
MONDAY...ONLY SOME SUBTLE CHANGES HEADING INTO MONDAY. SHORTWAVE
ENERGY OVER THE PLAINS WILL LIFT TO THE NORTHEAST OVER NW
WISCONSIN...BUT WITH VERY LITTLE IMPACT ON OUR WEATHER. WILL
CONTINUE TO HAVE NORTHERLY FLOW TOMORROW WITH SOME MINOR COLD
ADVECTION THAT WILL DROP 850MB TEMPS IN THE NEGATIVE LOW TO MID
TEENS. LIGHT LAKE EFFECT SNOW SHOWERS WILL PREVAIL OVER THE SNOW
BELT OF N-C WISCONSIN...WHILE MOSTLY CLOUDY CONDITIONS WILL BE THE
RULE ELSEWHERE. HIGHS IN THE MIDDLE 20S NORTH TO MIDDLE 30S
SOUTHEAST.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...THE MAIN FCST
CONCERN IS THE ARRIVAL OF COLDER ARCTIC AIR LATE IN THE NEXT WORK
WEEK.
A STRONG UPPER RIDGE WILL COVER THE EASTERN PACIFIC...SOUTHWEST
CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...WITH A
POSITIVELY-TILTED UPPER TROF MOVG OUT OF THE NORTHERN PLAINS INTO
THE WESTERN GREAT LAKES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON MONDAY NIGHT AND TUESDAY...BUT WITH A SFC RIDGE OF
HIGH PRESSURE IN PLACE...EXPECT MINIMAL IMPACT ON OUR WEATHER.
SHORT-WAVE ENERGY TOPPING THE WESTERN RIDGE AND DIVING INTO THE
NORTHERN PLAINS WILL HELP TO CARVE A BROAD TROF OVER THE CENTRAL
U.S. BY THURSDAY. A SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN
WI ON THURSDAY...WITH H8 TEMPS PLUMMETING TO AROUND -20 C LATE
THURSDAY NIGHT INTO FRIDAY. THIS WILL LEAD TO OUR COLDEST
TEMPERATURES SO FAR THIS SEASON. THE COLD SNAP WILL BE BRIEF...
AS SOUTHWEST WINDS DEVELOP IN THE WAKE OF THE RETREATING ARCTIC
HIGH OVER THE WEEKEND.
A LARGE RIDGE OF HIGH PRESSURE WILL BUILD INTO NW WI ON MONDAY
NIGHT...THEN MOVE THROUGH GRB CWA ON TUESDAY. LINGERING LAKE-EFFECT
SNOW SHOWERS OVER NC WI SHOULD COME TO AN END AS THE RIDGE AXIS
ARRIVES ON TUESDAY.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING ON THURSDAY.
THE ECMWF HAS BACKED OFF ON THE POTENTIAL FOR SNOW ALONG THE
ARCTIC FRONT ON THU NGT/FRI...AND IS FOCUSING FARTHER SE...FROM
SOUTHERN WI INTO LOWER MICHIGAN. WILL NEED TO KEEP AN EYE ON THIS
OVER THE NEXT FEW DAYS TO SEE IF THIS TREND WILL HOLD. CONFIDENCE
IS FAIRLY HIGH FOR THE ARRIVAL OF MUCH COLDER TEMPERATURES LATE IN
THE WORK WEEK...ALTHOUGH THE COLD IS EXPECTED TO BE SHORT-LIVED.
A WARM FRONT IS EXPECTED TO ARRIVE ON SUNDAY...WITH TEMPERATURES
CLIMBING BACK TO ABOVE NORMAL.
DESPITE THE PRESENCE OF A COLD AIR MASS FROM WEDNESDAY THROUGH
SATURDAY...WIND TRAJECTORIES WILL NOT BE FAVORABLE FOR LK-EFFECT
SNOW.
&&
.AVIATION...A SUBTLE SURFACE TROUGH DROPPING OVER CENTRAL AND EAST
CENTRAL WISCONSIN THIS EVENING WILL BE MARKED WITH A FEW FLURRIES
ALONG WITH A SHIFT OF WINDS FROM WEST TO NORTH. OTHERWISE CYCLONIC
FLOW TONIGHT INTO MONDAY WILL CONTINUE TO SUPPORT MAINLY MVFR
CIGS.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
220 PM CST SAT DEC 3 2011
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DEVELOPING
LOW PRESSURE SYSTEM MOVING NORTHEAST OVER SOUTH-CENTRAL KANSAS JUST
AHEAD OF A SHORTWAVE TROUGH. ATTACHED TO THE SURFACE LOW TO THE
NORTHEAST RUNS A COLD FRONT OVER CENTRAL IOWA INTO NORTHWEST
WISCONSIN. FIRST BATCH OF PRECIP IS RIDING ALONG THE 850MB
BAROCLINIC ZONE OVER THE SOUTHEASTERN HALF OF WISCONSIN THOUGH SOME
BREAKS ARE SPREADING OVER EASTERN IOWA AND NORTHERN ILLINOIS...THAT
MAY SPELL A BREAK IN THE PRECIP FOR A BRIEF PERIOD LATE THIS
AFTERNOON OVER E-C WISCONSIN. THE MAIN AXIS OF PRECIP...HOWEVER...
EXISTS JUST TO THE EAST OF THE SURFACE LOW ON THE NOSE OF A 60 KT
LLJ AND UPPER DIVERGENT AREA WITHIN THE COUPLED JET. SOME HIGHER
REFLECTIVITIES ARE ALSO DEVELOPING OVER WESTERN WISCONSIN WITHIN A
STRENGTHENING FGEN ZONE...SO WILL JUST START THE WINTER HEADLINES
WITH THE AFTERNOON PACKAGE. AS THE LOW TRACKS NORTHEAST OVER THE
NEXT 24 HOURS...THE OBVIOUS CONCERNS ARE SNOW AMOUNTS AND
HEADLINES.
TONIGHT...FOLLOWED A SREF/GFS BLEND TONIGHT...WHICH SPLITS THE
DIFFERENCE BETWEEN THE STRONGER NAM AND WEAKER ECMWF WHILE KEEPING
THE CONSENSUS TRACK. LOW PRESSURE OVER THE CENTRAL PLAINS WILL
RAPIDLY MOVE NE TOWARDS THE MID-MISSISSIPPI VALLEY THIS
EVENING...AND NORTHERN LAKE MICHIGAN BY 12Z SUNDAY. AHEAD OF THE
LOW...A BEEFY LLJ WILL SHIFT INTO SOUTHERN WISCONSIN THIS
EVENING...THEREBY INCREASING CONVERGENCE ALONG THE STALLED
BAROCLINIC ZONE STRETCHING ACROSS THE STATE...AND 850-700MB FGEN IN
THE PROCESS. COMBINED WITH STRONG QG FORCING FROM SHORTWAVE ENERGY
AND A WIDE OPEN GULF (PWATS 150-200 PCT OF NORMAL)...THE BEEFY SLUG
OF PRECIP OVER THE PLAINS WILL HAVE NO TROUBLE SPREADING ACROSS THE
STATE THIS EVENING. PTYPE REMAINS PROBLEMATIC AS THE 12Z MODEL RUNS
HAVE TRENDED SLIGHTLY WARMER WITH THE THERMAL PROFILE AS THE LOW
PUSHES WARMER AIR ALOFT SLIGHTLY FARTHER NORTH THAN PREVIOUS RUNS.
THIS WILL PLACE THE RAIN-SNOW MIX AREA FROM WOOD COUNTY TO NORTHERN
OCONTO AND MARINETTE. NORTH OF THE RAIN-SNOW LINE SHOULD RESIDE THE
AXIS OF HEAVIEST SNOWFALL...WHICH LINES UP WITH THE EXTRAPOLATED
SOUTHERN EDGE OF THE COMMA HEAD FROM APPROX MERRILL TO CRANDON.
WITH SLIGHTLY COLDER AIR IN PLACE COMPARED TO THE FIRST SNOW STORM IN
NOVEMBER...SNOW RATIOS WILL RUN BETWEEN 10-14:1 OVER THIS AREA
ACCORDING TO THE COBB SNOWFALL ALGORITHM. WITH QPFS AROUND 0.4 TO
0.5 INCHES...THIS AMOUNTS TO A GOOD 4-6 INCH SWATH OF SNOW TONIGHT
(5 TO 7 INCHES OVERALL)...THOUGH THE BULK OF THE PRECIP WILL LIKELY FALL
THIS EVENING. THE FOX VALLEY AND LAKESHORE WILL RESIDE WITHIN THE
WARM SECTOR OF THE STORM...WHICH MEANS MOSTLY RAIN TONIGHT...THOUGH
SOME SNOW MAY MIX IN LATE. ENTERTAINED SOME THOUGHTS OF UPGRADING TO
A WARNING GIVEN THE HEAVY SNOW OBS UPSTREAM...BUT GIVEN THE
RELATIVELY LOW IMPACT OF THE SNOW (DURING THE NIGHT ON A
WEEKEND)...WILL STICK WITH ADVISORY HEADLINES. ALSO THOUGHT ABOUT
TRIMMING THE ADVISORY TO THE NW BY A ROW OF COUNTIES...BUT
COORDINATION WITH SURROUNDING OFFICES YIELDED A RELUCTANCE...DUE TO
THE SLOPPINESS OF THE MIX AND POTENTIAL FOR FREEZING DRIZZLE. AS A
RESULT...WILL KEEP CURRENT HEADLINES AS THEY CURRENTLY STAND BUT
STRESS THE HEAVY SNOWFALL RATES ARRIVING THIS EVENING.
SUNDAY...THE LOW PRESSURE WILL QUICKLY EXIT TO SOUTHEAST ONTARIO BY
18Z SUNDAY BUT WILL HAVE THE BACK EDGE OF THE COMMA HEAD SHIFTING NE
OVER N-C AND FAR NORTHEAST WISCONSIN. SOME MID-LEVEL FGEN WILL
LINGER WHICH WILL RESULT IN ANOTHER HALF INCH TO AN INCH OVER N-C
WISCONSIN EARLY IN THE MORNING. BUT OTHERWISE...SNOW WILL BE
TAPERING DOWN TO JUST FLURRIES IN THE MORNING...WHILE COLDER AIR
FILTERS ACROSS THE REGION. LOW LEVEL TROUGHINESS AND CYCLONIC FLOW
WILL HANG AROUND FOR MUCH OF THE DAY...SO NOT ANTICIPATING MUCH
CLEARING TOMORROW. HIGHS MAINLY IN THE LOW TO MIDDLE 30S.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...THE MAIN FCST
CONCERNS WILL BE MINOR LAKE EFFECT SNOW POTENTIAL OVER NORTHERN
WI EARLY IN THE PERIOD...THEN THE POTENTIAL FOR SNOW AND MUCH
COLDER TEMPERATURES WITH AN ARCTIC FRONTAL PASSAGE LATE NEXT
WEEK.
A STRONG...HIGH AMPLITUDE RIDGE WILL COVER THE EASTERN PACIFIC...
WESTERN CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...
WITH A POSITIVELY-TILTED UPPER TROF EXTENDING FROM CENTRAL CANADA
INTO THE SOUTHWEST UNITED STATES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON TUESDAY...WITH LITTLE IMPACT ON OUR WEATHER. SHORT-WAVE
ENERGY WILL TOP THE WESTERN RIDGE EARLY NEXT WEEK...THEN EVENTUALLY
HELP TO CARVE A BROAD TROF OVER THE CENTRAL U.S. BY THU/FRI. A
SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN WI LATE IN THE WEEK...
WITH H8 TEMPS PLUMMETING TO AROUND -20 C. THIS WILL LEAD TO OUR
COLDEST TEMPERATURES SO FAR THIS SEASON.
A LARGE RIDGE OF HIGH PRESSURE WILL BE CENTERED OVER THE NORTHERN
ROCKIES AND NORTHERN PLAINS SUN NGT INTO MON...WITH COLD NORTH
FLOW RESULTING IN SCT LAKE-EFFECT SNOW SHOWERS OVER MAINLY NC WI.
THE SNOW SHOWERS MAY LINGER INTO MONDAY NIGHT...BUT SHOULD COME TO
AN END ON TUESDAY AS THE RIDGE AXIS PUSHES ACROSS WI.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING SOMETIME DURING
THE THU/FRI TIME FRAME. DURING THIS PERIOD...LLVL FLOW IS EXPECTED
TO BE TOO WESTERLY FOR LK-EFFECT. THE ECMWF AND A FEW OF THE GFS
ENSEMBLE MEMBERS SUGGEST THAT A SFC WAVE WILL DEVELOP ALONG THE
ARCTIC BOUNDARY LATE IN THE WEEK...AS THE RRQ OF A STRONG UPPER
LEVEL JET PULLS THROUGH THE REGION. IF THIS PLAYS OUT...WE COULD
BRING SEE SEVERAL INCHES OF POWDERY SNOW SOMETIME DURING THE
THURSDAY NIGHT TO SATURDAY PERIOD. FOR NOW...WILL FOLLOW THE
CONCENSUS OF AREA OFFICES...AND JUST MENTION SMALL POPS ACROSS OUR
SOUTHERN AND EASTERN COUNTIES ON THU NGT/FRI. THERE IS A HIGHER
DEGREE OF CONFIDENCE IN A TREND TOWARD MUCH COLDER TEMPERATURES
LATE IN THE WEEK...ALTHOUGH THE NEW ECMWF IS SLOWER WITH THE
TIMING OF THE ARCTIC BOUNDARY. SUBSEQUENT FCSTS SHOULD BE BETTER
ABLE TO PINPOINT THE FRONTAL TIMING AND SNOWFALL POTENTIAL LATE
NEXT WEEK.
&&
.AVIATION...MVFR TO IFR CIGS/VSBYS PRIMARILY ACROSS THE
REGION...THOUGH 1/4SM VSBYS ARE HANGING TOUGH AT AUW/CWA. THE VERY
LOW VSBYS OVER THE CENTRAL WISCONSIN TAF SITES SHOULD IMPROVE ONCE
PRECIP ARRIVES EARLY THIS AFTERNOON. LOW PRESSURE WILL TRACK ACROSS
THE REGION TONIGHT. MODEL THERMAL PROFILES ARE VERY CLOSE TO THE
FREEZING MARK IN THE LOW LEVELS...SO INCLUDED A RAIN-SNOW MIX
THROUGH THIS EVENING AT CWA/AUW. WILL SEE MOSTLY RAIN OVER THE FOX
VALLEY IN THE WARM SECTOR UNTIL LATE TONIGHT WHEN RAIN SWITCHES OVER
TO SNOW. WILL SEE A PERIOD OF A FEW HOURS OF HEAVY SNOW AT RHI
THIS EVENING WHEN SHOULD SEE SEVERAL INCHES. THE PRECIP WILL BE
EXITING THE AREA LATE TONIGHT INTO TOMORROW MORNING FROM SW TO NE.
VSBYS AND CIGS WILL BE GRADUALLY IMPROVING AS THE SNOW DIMINISHES.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ005-010>013-
018-019-021-030-035.
&&
$$
MPC/TSK
AREA FORECAST DISCUSSION...UPDATED
NWS LA CROSSE WI
140 PM CST SAT DEC 3 2011
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
343 AM CST SAT DEC 3 2011
MAIN FORECAST CONCERN IS ON MIXED PRECIPITATION THROUGH
TONIGHT...ALONG WITH SNOWFALL AMOUNTS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE EAST PACIFIC...SPLIT TROUGHING FROM
MANITOBA SOUTHWEST INTO ARIZONA...AND BUILDING RIDGING FROM THE
SOUTHEASTERN U.S. INTO THE GREAT LAKES REGION. WITHIN THE SPLIT
TROUGHING...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST NEW MEXICO
WITH A NICE BAROCLINIC LEAF ON WATER VAPOR NORTHEAST OF IT. 850MB
WINDS FAIRLY STRONG AHEAD OF THE SPLIT TROUGHING...RANGING FROM
40-60 KNOTS OUT OF THE SOUTH-SOUTHWEST FROM TEXAS INTO KANSAS AND
NORTHEAST INTO THE FORECAST AREA. THESE WINDS HAVE BEEN RAPIDLY
ADVECTING WARMER AIR AND MOISTURE NORTHWARD...CAUSING RAIN TO
BREAK OUT ACROSS IOWA...FAR SOUTHEASTERN MINNESOTA AND MUCH OF
WISCONSIN EXCLUDING THE NORTHWEST PART. 08Z PRECIPITABLE WATER
ANALYSIS FROM THE RUC SHOWS VALUES OF 0.75 TO 0.9 INCHES IN THE
SOUTHERN PORTION OF THE FORECAST AREA...OR ABOUT 200 PERCENT ABOVE
NORMAL. 2 METER AIR TEMPERATURES HAVE CLIMBED TO AT OR ABOVE 32F
AT MOST LOCATIONS AND DEWPOINTS ARE ALMOST THE SAME NOW. THIS
SHOULD BE REDUCING THE FREEZING OF THE RAIN AT THE SURFACE.
TODAY AND TONIGHT...SHORTWAVE OVER NEW MEXICO IS FORECAST TO
GRADUALLY ACCELERATE TO THE NORTHEAST DURING THIS PERIOD AS
A POTENT SHORTWAVE DROPS DOWN INTO MONTANA. INITIAL ISENTROPIC
LIFTING TAKING PLACE TO PRODUCE CURRENT PRECIPITATION SHOULD HOLD
FAIRLY STEADY THROUGH THE MORNING. WITH WARM ADVECTION OCCURRING...
ANY FREEZING OF THE PRECIPITATION SHOULD BE LIMITED TO BEFORE
13Z...THEN RAIN/DRIZZLE IS ANTICIPATED. DURING THE AFTERNOON...LOW
TO MID-LEVEL FRONTOGENESIS WILL INTENSIFY OVER THE SOUTHWEST
PORTION OF THE FORECAST AREA...SPREADING NORTHEAST DURING THE
EVENING. THIS FRONTOGENESIS IS CAUSED BY A COMBINATION FROM THE
DPVA PRODUCED AHEAD OF THE APPROACHING NEW MEXICO SHORTWAVE...AS
WELL AS A NEAR COUPLED UPPER JET STRUCTURE DEVELOPING. IN
ADDITION...CROSS-SECTIONS INDICATE THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...ALLOWING FOR POTENTIAL FOR
A FEW CONVECTIVE ELEMENTS. WITH PRECIPITABLE WATER VALUES HOLDING
FAIRLY STEADY INTO THE EVENING...NEEDLESS TO SAY THE LATE
AFTERNOON INTO THE EVENING PERIOD IS OF MOST CONCERN FOR HEAVIEST
PRECIPITATION. GIVEN THE HIGHER PRECIPITATION RATES ALLOWING FOR
DIABATIC COOLING AND THE SURFACE FLOW TURNING NORTHERLY TO ALLOW FOR
COLD ADVECTION...THE AFTERNOON AND EVENING PRECIPITATION SHOULD
GRADUALLY CHANGE OVER TO SNOW...QUICKEST OVER THE NORTHWEST HALF
OF THE FORECAST AREA. 03.00Z MODEL QPF SPREADS ARE SOMEWHAT
HIGH...RANGING FROM 0.20-0.60 INCHES FOR 18-06Z. STILL...WITH SNOW
TO WATER RATIOS LIKELY TO STAY AROUND A 10 TO 1 AVERAGE GIVEN DEEP
AGGREGATION LAYER NOTED ON SOUNDINGS...LIKELY TO END UP WITH
SNOWFALL AMOUNTS IN THIS TIME WINDOW AT MOST UP TO 5 INCHES. SINCE
THIS IS AN INCH BELOW WARNING CRITERIA...AND MODELS TOO COLD
RIGHT NOW WITH HOURLY TEMPERATURES SUGGESTING PRECIPITATION COULD
END UP BEING EVEN MORE RAIN FOR THE AFTERNOON...AN ADVISORY SEEMS
TO BE THE BETTER REPLACEMENT FOR THE WATCH RIGHT NOW. DURING THE
OVERNIGHT HOURS...THE PRECIPITATION SHOULD SLOWLY START LIFTING TO
THE NORTHEAST WITH THE SHORTWAVE. HOWEVER...PLENTY OF LOW LEVEL
STILL EXISTS. THIS BRINGS UP A CONCERN...AS ONCE THE SHORTWAVE
MOVES IN THE ICE MAY SCOUR OUT...RESULTING IN RAIN/FREEZING RAIN.
THE BEST CHANCE FOR THIS TO OCCUR IS EAST OF A LINE FROM CHARLES
CITY IOWA TO LA CROSSE AND WISCONSIN RAPIDS. DID PUT IN A FEW
HUNDREDTHS OF ICE ACCUMULATION NEAR THIS LINE. WITH THE ICE
ACCUMULATION AND TO ADD A BUFFER IN CASE THE PRECIPITATION CHANGES
TO SNOW QUICKER TONIGHT...ADDED ANOTHER ROW OF COUNTIES JUST EAST
OF THE PREVIOUS WATCH FOR AN ADVISORY. REGARDING TEMPERATURES...
INCREASED THEM BOTH TODAY AND TONIGHT GIVEN CURRENT WARMER TRENDS.
SUNDAY THROUGH MONDAY NIGHT...MUCH QUIETER TIME PERIOD. SHORTWAVE
TROUGHING DIGGING INTO MONTANA TONIGHT IS FORECAST BY ALL MODELS
TO MARCH SLOWLY EAST...REACHING THE WESTERN END OF THE FORECAST
AREA AROUND 12Z TUESDAY. ALTHOUGH THE FORECAST AREA RESIDES IN
SOUTHWEST FLOW ALOFT...ALL OF THE SHORTWAVES IN THAT SOUTHWEST
FLOW TO HELP PRODUCE PRECIPITATION LOOK TO STAY TO THE SOUTHEAST
OF HERE. IN ADDITION...THE SHORTWAVE MOVING THROUGH TONIGHT HELPS
TO SCOUR OUT MUCH OF THE MOISTURE...NOTED BY PRECIPITABLE WATER
VALUES FALLING TO 0.25 INCH OR LESS BY 21Z SUNDAY. DID MAINTAIN
SOME LOW 20-30 PERCENT CHANCES FOR THE EASTERN TWO THIRDS OF THE
FORECAST AREA ON SUNDAY...DUE TO LINGERING LOW LEVEL LIFT.
AGAIN...THE PRESENCE OF ICE IS QUESTIONABLE...ESPECIALLY OVER
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. AS A RESULT...HAVE
MENTIONED A SNOW/FREEZING DRIZZLE MIX. AFTER THAT...DRY WEATHER
WILL BE THE RULE...WITH ONLY SOME INCREASE OF MID/HIGH CLOUDS AS
THE MONTANA SHORTWAVE TROUGHING APPROACHES. BIGGER IMPACT
TEMPERATURES. 850MB TEMPS AT 12Z SUNDAY SHOULD RANGE FROM -4C EAST
TO -8C WEST. THESE COOL THROUGH THE DAY SUNDAY...SO HIGHS SHOULD
END UP CLOSE TO THE MORNING LOWS. FURTHER COOLING OF 850MB TEMPS
IS PROGGED FOR MONDAY...DROPPING TO -10 TO -14C. THEREFORE...
HIGHS IN MOST LOCATIONS LOOK TO ONLY TOP OUT IN THE 20S. MORE
TEENS AND SINGLE DIGIT READINGS ABOVE ZERO EXPECTED AT NIGHT WITH
NOCTURNAL COOLING.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
343 AM CST SAT DEC 3 2011
03.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES CONTINUE TO PAINT A
COLDER THAN NORMAL PATTERN FOR THE FORECAST AREA AS A POLAR VORTEX
SETS UP OVER HUDSON BAY BY LATE IN THE WEEK. SHORTWAVE TROUGH WILL
MOVE EAST TO WEST ACROSS THE AREA ON TUESDAY...NOT REALLY BRINGING
ANY PRECIPITATION WITH IT DUE TO LACK OF MOISTURE. HOWEVER...850MB
TEMPS FALL FURTHER...DOWN TO -11 TO -15C. BRIEF WARMING SHOULD OCCUR
TUESDAY NIGHT AS A WEAK UPPER RIDGE CROSSES IN THE WAKE OF TUESDAYS
SHORTWAVE TROUGH. THEN THIS GETS REPLACE BY A ZONAL FLOW FOR
WEDNESDAY INTO THURSDAY IN RESPONSE TO A SERIES OF SHORTWAVES
CROSSING SOUTHERN CANADA. THIS FLOW SETUP SHOULD ALLOW FOR DRY BUT
COOL CONDITIONS TO CONTINUE. ALL MODELS THEN INDICATE A DEEP
TROUGH DROPPING SOUTH THROUGH THE NORTHERN PLAINS THURSDAY NIGHT.
AHEAD OF THIS TROUGH...SOME PRECIP COULD OCCUR DUE TO DPVA AND
ISENTROPIC LIFT...THOUGH MOISTURE AGAIN IS QUESTIONABLE. INCLUDED
A 20 PERCENT CHANCE OF SNOW ACROSS THE SOUTHERN PORTIONS OF THE
FORECAST AREA...IN-LINE WITH THE 03.00Z GFS/ECMWF. THE UPPER
TROUGHING MOVES INTO THE AREA ON FRIDAY...BRINGING AIR MORE OF
ARCTIC ORIGIN ACROSS WITH 850MB TEMPS TANKING TO AROUND -20C. FOR
NOW FOLLOWED A CONSENSUS OF GUIDANCE FOR HIGHS AND LOWS THROUGHOUT
THE LONG TERM FORECAST...BUT MAY NEED TO LOWER HIGHS/LOWS FOR
FRIDAY AND FRIDAY NIGHT IF THIS -20C AT 850MB AIRMASS FORECAST
PERSISTS.
&&
.AVIATION...THROUGH 18Z SUNDAY
1135 AM CST SAT DEC 3 2011
PERIODS OF IFR CONDITIONS IN SNOW CAN BE EXPECTED AT TAF SITES
THROUGH LATE THIS EVENING. PLAN ON A RAIN/SNOW MIX EARLY THIS
AFTERNOON...SWITCHING OVER TO ALL SNOW BY MID AFTERNOON AT KRST
AND BY LATE AFTERNOON AT KLSE. VISIBILITIES WILL BE REDUCED TO
LESS THAN ONE MILE AT TIMES IN THE HEAVIER SNOWS. LOOK FOR
CEILINGS TO FALL INTO THE LIFR CATEGORY AT KRST DURING THE
HEAVIEST SNOW LATE THIS AFTERNOON INTO EARLY THIS EVENING...WITH
CEILINGS FALLING TO AROUND 200 FT. VLIFR CONDITIONS MAY DEVELOP IN
THE HEAVIEST SNOWS WITH VISIBILITIES POSSIBLY FALLING TO AROUND
ONE QUARTER OF A MILE A TIMES. THE SNOW WILL TAPER BY 09Z TONIGHT
AT KRST. PRECIPITATION IS EXPECTED TO SWITCH OVER FREEZING DRIZZLE
BY 08Z AT KLSE...WITH FREEZING DRIZZLE ENDING AROUND 11Z. LOOK
FOR CEILINGS TO GRADUALLY IMPROVE EARLY SUNDAY MORNING...WITH
CEILINGS IN THE 800 TO 1000 FT RANGE AROUND DAY BREAK. LOOK FOR
IFR/MVFR STRATUS TO PERSIST AT THE TAF SITES THROUGH THE LATE
MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
139 PM CST SAT DEC 3 2011
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR WIZ041>043-053.
WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ017-029-
032>034.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR MNZ096.
WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR MNZ079-086>088-
094-095.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR IAZ010-011-019.
WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
547 AM CST SAT DEC 3 2011
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
343 AM CST SAT DEC 3 2011
MAIN FORECAST CONCERN IS ON MIXED PRECIPITATION THROUGH
TONIGHT...ALONG WITH SNOWFALL AMOUNTS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE EAST PACIFIC...SPLIT TROUGHING FROM
MANITOBA SOUTHWEST INTO ARIZONA...AND BUILDING RIDGING FROM THE
SOUTHEASTERN U.S. INTO THE GREAT LAKES REGION. WITHIN THE SPLIT
TROUGHING...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST NEW MEXICO
WITH A NICE BAROCLINIC LEAF ON WATER VAPOR NORTHEAST OF IT. 850MB
WINDS FAIRLY STRONG AHEAD OF THE SPLIT TROUGHING...RANGING FROM
40-60 KNOTS OUT OF THE SOUTH-SOUTHWEST FROM TEXAS INTO KANSAS AND
NORTHEAST INTO THE FORECAST AREA. THESE WINDS HAVE BEEN RAPIDLY
ADVECTING WARMER AIR AND MOISTURE NORTHWARD...CAUSING RAIN TO
BREAK OUT ACROSS IOWA...FAR SOUTHEASTERN MINNESOTA AND MUCH OF
WISCONSIN EXCLUDING THE NORTHWEST PART. 08Z PRECIPITABLE WATER
ANALYSIS FROM THE RUC SHOWS VALUES OF 0.75 TO 0.9 INCHES IN THE
SOUTHERN PORTION OF THE FORECAST AREA...OR ABOUT 200 PERCENT ABOVE
NORMAL. 2 METER AIR TEMPERATURES HAVE CLIMBED TO AT OR ABOVE 32F
AT MOST LOCATIONS AND DEWPOINTS ARE ALMOST THE SAME NOW. THIS
SHOULD BE REDUCING THE FREEZING OF THE RAIN AT THE SURFACE.
TODAY AND TONIGHT...SHORTWAVE OVER NEW MEXICO IS FORECAST TO
GRADUALLY ACCELERATE TO THE NORTHEAST DURING THIS PERIOD AS
A POTENT SHORTWAVE DROPS DOWN INTO MONTANA. INITIAL ISENTROPIC
LIFTING TAKING PLACE TO PRODUCE CURRENT PRECIPITATION SHOULD HOLD
FAIRLY STEADY THROUGH THE MORNING. WITH WARM ADVECTION OCCURRING...
ANY FREEZING OF THE PRECIPITATION SHOULD BE LIMITED TO BEFORE
13Z...THEN RAIN/DRIZZLE IS ANTICIPATED. DURING THE AFTERNOON...LOW
TO MID-LEVEL FRONTOGENESIS WILL INTENSIFY OVER THE SOUTHWEST
PORTION OF THE FORECAST AREA...SPREADING NORTHEAST DURING THE
EVENING. THIS FRONTOGENESIS IS CAUSED BY A COMBINATION FROM THE
DPVA PRODUCED AHEAD OF THE APPROACHING NEW MEXICO SHORTWAVE...AS
WELL AS A NEAR COUPLED UPPER JET STRUCTURE DEVELOPING. IN
ADDITION...CROSS-SECTIONS INDICATE THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...ALLOWING FOR POTENTIAL FOR
A FEW CONVECTIVE ELEMENTS. WITH PRECIPITABLE WATER VALUES HOLDING
FAIRLY STEADY INTO THE EVENING...NEEDLESS TO SAY THE LATE
AFTERNOON INTO THE EVENING PERIOD IS OF MOST CONCERN FOR HEAVIEST
PRECIPITATION. GIVEN THE HIGHER PRECIPITATION RATES ALLOWING FOR
DIABATIC COOLING AND THE SURFACE FLOW TURNING NORTHERLY TO ALLOW FOR
COLD ADVECTION...THE AFTERNOON AND EVENING PRECIPITATION SHOULD
GRADUALLY CHANGE OVER TO SNOW...QUICKEST OVER THE NORTHWEST HALF
OF THE FORECAST AREA. 03.00Z MODEL QPF SPREADS ARE SOMEWHAT
HIGH...RANGING FROM 0.20-0.60 INCHES FOR 18-06Z. STILL...WITH SNOW
TO WATER RATIOS LIKELY TO STAY AROUND A 10 TO 1 AVERAGE GIVEN DEEP
AGGREGATION LAYER NOTED ON SOUNDINGS...LIKELY TO END UP WITH
SNOWFALL AMOUNTS IN THIS TIME WINDOW AT MOST UP TO 5 INCHES. SINCE
THIS IS AN INCH BELOW WARNING CRITERIA...AND MODELS TOO COLD
RIGHT NOW WITH HOURLY TEMPERATURES SUGGESTING PRECIPITATION COULD
END UP BEING EVEN MORE RAIN FOR THE AFTERNOON...AN ADVISORY SEEMS
TO BE THE BETTER REPLACEMENT FOR THE WATCH RIGHT NOW. DURING THE
OVERNIGHT HOURS...THE PRECIPITATION SHOULD SLOWLY START LIFTING TO
THE NORTHEAST WITH THE SHORTWAVE. HOWEVER...PLENTY OF LOW LEVEL
STILL EXISTS. THIS BRINGS UP A CONCERN...AS ONCE THE SHORTWAVE
MOVES IN THE ICE MAY SCOUR OUT...RESULTING IN RAIN/FREEZING RAIN.
THE BEST CHANCE FOR THIS TO OCCUR IS EAST OF A LINE FROM CHARLES
CITY IOWA TO LA CROSSE AND WISCONSIN RAPIDS. DID PUT IN A FEW
HUNDREDTHS OF ICE ACCUMULATION NEAR THIS LINE. WITH THE ICE
ACCUMULATION AND TO ADD A BUFFER IN CASE THE PRECIPITATION CHANGES
TO SNOW QUICKER TONIGHT...ADDED ANOTHER ROW OF COUNTIES JUST EAST
OF THE PREVIOUS WATCH FOR AN ADVISORY. REGARDING TEMPERATURES...
INCREASED THEM BOTH TODAY AND TONIGHT GIVEN CURRENT WARMER TRENDS.
SUNDAY THROUGH MONDAY NIGHT...MUCH QUIETER TIME PERIOD. SHORTWAVE
TROUGHING DIGGING INTO MONTANA TONIGHT IS FORECAST BY ALL MODELS
TO MARCH SLOWLY EAST...REACHING THE WESTERN END OF THE FORECAST
AREA AROUND 12Z TUESDAY. ALTHOUGH THE FORECAST AREA RESIDES IN
SOUTHWEST FLOW ALOFT...ALL OF THE SHORTWAVES IN THAT SOUTHWEST
FLOW TO HELP PRODUCE PRECIPITATION LOOK TO STAY TO THE SOUTHEAST
OF HERE. IN ADDITION...THE SHORTWAVE MOVING THROUGH TONIGHT HELPS
TO SCOUR OUT MUCH OF THE MOISTURE...NOTED BY PRECIPITABLE WATER
VALUES FALLING TO 0.25 INCH OR LESS BY 21Z SUNDAY. DID MAINTAIN
SOME LOW 20-30 PERCENT CHANCES FOR THE EASTERN TWO THIRDS OF THE
FORECAST AREA ON SUNDAY...DUE TO LINGERING LOW LEVEL LIFT.
AGAIN...THE PRESENCE OF ICE IS QUESTIONABLE...ESPECIALLY OVER
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. AS A RESULT...HAVE
MENTIONED A SNOW/FREEZING DRIZZLE MIX. AFTER THAT...DRY WEATHER
WILL BE THE RULE...WITH ONLY SOME INCREASE OF MID/HIGH CLOUDS AS
THE MONTANA SHORTWAVE TROUGHING APPROACHES. BIGGER IMPACT
TEMPERATURES. 850MB TEMPS AT 12Z SUNDAY SHOULD RANGE FROM -4C EAST
TO -8C WEST. THESE COOL THROUGH THE DAY SUNDAY...SO HIGHS SHOULD
END UP CLOSE TO THE MORNING LOWS. FURTHER COOLING OF 850MB TEMPS
IS PROGGED FOR MONDAY...DROPPING TO -10 TO -14C. THEREFORE...
HIGHS IN MOST LOCATIONS LOOK TO ONLY TOP OUT IN THE 20S. MORE
TEENS AND SINGLE DIGIT READINGS ABOVE ZERO EXPECTED AT NIGHT WITH
NOCTURNAL COOLING.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
343 AM CST SAT DEC 3 2011
03.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES CONTINUE TO PAINT A
COLDER THAN NORMAL PATTERN FOR THE FORECAST AREA AS A POLAR VORTEX
SETS UP OVER HUDSON BAY BY LATE IN THE WEEK. SHORTWAVE TROUGH WILL
MOVE EAST TO WEST ACROSS THE AREA ON TUESDAY...NOT REALLY BRINGING
ANY PRECIPITATION WITH IT DUE TO LACK OF MOISTURE. HOWEVER...850MB
TEMPS FALL FURTHER...DOWN TO -11 TO -15C. BRIEF WARMING SHOULD OCCUR
TUESDAY NIGHT AS A WEAK UPPER RIDGE CROSSES IN THE WAKE OF TUESDAYS
SHORTWAVE TROUGH. THEN THIS GETS REPLACE BY A ZONAL FLOW FOR
WEDNESDAY INTO THURSDAY IN RESPONSE TO A SERIES OF SHORTWAVES
CROSSING SOUTHERN CANADA. THIS FLOW SETUP SHOULD ALLOW FOR DRY BUT
COOL CONDITIONS TO CONTINUE. ALL MODELS THEN INDICATE A DEEP
TROUGH DROPPING SOUTH THROUGH THE NORTHERN PLAINS THURSDAY NIGHT.
AHEAD OF THIS TROUGH...SOME PRECIP COULD OCCUR DUE TO DPVA AND
ISENTROPIC LIFT...THOUGH MOISTURE AGAIN IS QUESTIONABLE. INCLUDED
A 20 PERCENT CHANCE OF SNOW ACROSS THE SOUTHERN PORTIONS OF THE
FORECAST AREA...IN-LINE WITH THE 03.00Z GFS/ECMWF. THE UPPER
TROUGHING MOVES INTO THE AREA ON FRIDAY...BRINGING AIR MORE OF
ARCTIC ORIGIN ACROSS WITH 850MB TEMPS TANKING TO AROUND -20C. FOR
NOW FOLLOWED A CONSENSUS OF GUIDANCE FOR HIGHS AND LOWS THROUGHOUT
THE LONG TERM FORECAST...BUT MAY NEED TO LOWER HIGHS/LOWS FOR
FRIDAY AND FRIDAY NIGHT IF THIS -20C AT 850MB AIRMASS FORECAST
PERSISTS.
&&
.AVIATION...TODAY AND TONIGHT
547 AM CST SAT DEC 3 2011
A SIGNIFICANT WINTER STORM WILL IMPACT THE TAF SITES WITH MVFR/IFR
CIGS/VSBYS MUCH OF TODAY/TONIGHT...WITH CONDITIONS IMPROVING TO
MVFR/VFR ON SUNDAY. THE TAF SITES WILL SEE A BREAK FROM MUCH OF THE
PRECIP THIS MORNING HOWEVER IFR/MVFR CIGS AND SOME MVFR VSBYS IN BR
WILL REMAIN ACROSS THE AREA. AS THE LOW LIFTS TOWARD THE UPPER
MIDWEST THIS AFTERNOON...PRECIP WILL INCREASE/SPREAD ACROSS THE TAF
SITES... MAINLY -RA AT KLSE AND A -RA/-SN MIX AT KRST. COLDER AIR
WILL SPREAD IN DURING THE AFTERNOON AND EARLY EVENING...CHANGING THE
MIX TO ALL SNOW AT KRST DURING THE MID AFTERNOON AND AROUND 00Z AT
KLSE. THE STRONGEST OF THE FORCING/LIFT WITH THE STORM SYSTEM WILL
MOVE ACROSS THE TAF SITES THIS EVENING...WITH A 4 TO 6 HR PERIOD OF
IFR TO LIFR CIGS/VSBYS IN SNOW EXPECTED. SNOWFALL IS EXPECTED TO
IMPACT AIRPORT OPS AT BOTH KRST/KLSE WITH 3 TO 6 INCHES AT KRST AND
1 TO 3 INCHES AT KLSE. AS THE LOW MOVES EAST OF THE AREA LATER
TONIGHT AND THE LIFT GRADUALLY WEAKENS CIGS/VSBYS EXPECTED TO
IMPROVE AS THE -SN TAPERS OFF/ENDS AND DRIER AIR STARTS TO MOVE IN
FROM THE NORTHWEST. WITH LOSS OF ICE IN THE CLOUDS LATER TONIGHT...
KLSE MAY SEE SOME FZDZ BEFORE THE PRECIP ENDS LATE TONIGHT. LEFT
THIS OUT OF THE KLSE TAF FOR NOW GIVEN LESSER CONFIDENCE IN THE
DETAILS FOR LATE TONIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 AM CST SAT DEC 3 2011
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR WIZ041>044-053.
FREEZING RAIN ADVISORY UNTIL 7 AM CST THIS MORNING FOR WIZ029-
032>034-041>044-053>055-061.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SUNDAY FOR
WIZ017-029-032>034.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR MNZ096.
FREEZING RAIN ADVISORY UNTIL 7 AM CST THIS MORNING FOR MNZ079-
086>088-094>096.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SUNDAY FOR
MNZ079-086>088-094-095.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR IAZ010-011-019-029.
FREEZING RAIN ADVISORY UNTIL 7 AM CST THIS MORNING FOR
IAZ008>011-018-019-029-030.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SUNDAY FOR
IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
344 AM CST SAT DEC 3 2011
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
343 AM CST SAT DEC 3 2011
MAIN FORECAST CONCERN IS ON MIXED PRECIPITATION THROUGH
TONIGHT...ALONG WITH SNOWFALL AMOUNTS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE EAST PACIFIC...SPLIT TROUGHING FROM
MANITOBA SOUTHWEST INTO ARIZONA...AND BUILDING RIDGING FROM THE
SOUTHEASTERN U.S. INTO THE GREAT LAKES REGION. WITHIN THE SPLIT
TROUGHING...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST NEW MEXICO
WITH A NICE BAROCLINIC LEAF ON WATER VAPOR NORTHEAST OF IT. 850MB
WINDS FAIRLY STRONG AHEAD OF THE SPLIT TROUGHING...RANGING FROM
40-60 KNOTS OUT OF THE SOUTH-SOUTHWEST FROM TEXAS INTO KANSAS AND
NORTHEAST INTO THE FORECAST AREA. THESE WINDS HAVE BEEN RAPIDLY
ADVECTING WARMER AIR AND MOISTURE NORTHWARD...CAUSING RAIN TO
BREAK OUT ACROSS IOWA...FAR SOUTHEASTERN MINNESOTA AND MUCH OF
WISCONSIN EXCLUDING THE NORTHWEST PART. 08Z PRECIPITABLE WATER
ANALYSIS FROM THE RUC SHOWS VALUES OF 0.75 TO 0.9 INCHES IN THE
SOUTHERN PORTION OF THE FORECAST AREA...OR ABOUT 200 PERCENT ABOVE
NORMAL. 2 METER AIR TEMPERATURES HAVE CLIMBED TO AT OR ABOVE 32F
AT MOST LOCATIONS AND DEWPOINTS ARE ALMOST THE SAME NOW. THIS
SHOULD BE REDUCING THE FREEZING OF THE RAIN AT THE SURFACE.
TODAY AND TONIGHT...SHORTWAVE OVER NEW MEXICO IS FORECAST TO
GRADUALLY ACCELERATE TO THE NORTHEAST DURING THIS PERIOD AS
A POTENT SHORTWAVE DROPS DOWN INTO MONTANA. INITIAL ISENTROPIC
LIFTING TAKING PLACE TO PRODUCE CURRENT PRECIPITATION SHOULD HOLD
FAIRLY STEADY THROUGH THE MORNING. WITH WARM ADVECTION OCCURRING...
ANY FREEZING OF THE PRECIPITATION SHOULD BE LIMITED TO BEFORE
13Z...THEN RAIN/DRIZZLE IS ANTICIPATED. DURING THE AFTERNOON...LOW
TO MID-LEVEL FRONTOGENESIS WILL INTENSIFY OVER THE SOUTHWEST
PORTION OF THE FORECAST AREA...SPREADING NORTHEAST DURING THE
EVENING. THIS FRONTOGENESIS IS CAUSED BY A COMBINATION FROM THE
DPVA PRODUCED AHEAD OF THE APPROACHING NEW MEXICO SHORTWAVE...AS
WELL AS A NEAR COUPLED UPPER JET STRUCTURE DEVELOPING. IN
ADDITION...CROSS-SECTIONS INDICATE THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...ALLOWING FOR POTENTIAL FOR
A FEW CONVECTIVE ELEMENTS. WITH PRECIPITABLE WATER VALUES HOLDING
FAIRLY STEADY INTO THE EVENING...NEEDLESS TO SAY THE LATE
AFTERNOON INTO THE EVENING PERIOD IS OF MOST CONCERN FOR HEAVIEST
PRECIPITATION. GIVEN THE HIGHER PRECIPITATION RATES ALLOWING FOR
DIABATIC COOLING AND THE SURFACE FLOW TURNING NORTHERLY TO ALLOW FOR
COLD ADVECTION...THE AFTERNOON AND EVENING PRECIPITATION SHOULD
GRADUALLY CHANGE OVER TO SNOW...QUICKEST OVER THE NORTHWEST HALF
OF THE FORECAST AREA. 03.00Z MODEL QPF SPREADS ARE SOMEWHAT
HIGH...RANGING FROM 0.20-0.60 INCHES FOR 18-06Z. STILL...WITH SNOW
TO WATER RATIOS LIKELY TO STAY AROUND A 10 TO 1 AVERAGE GIVEN DEEP
AGGREGATION LAYER NOTED ON SOUNDINGS...LIKELY TO END UP WITH
SNOWFALL AMOUNTS IN THIS TIME WINDOW AT MOST UP TO 5 INCHES. SINCE
THIS IS AN INCH BELOW WARNING CRITERIA...AND MODELS TOO COLD
RIGHT NOW WITH HOURLY TEMPERATURES SUGGESTING PRECIPITATION COULD
END UP BEING EVEN MORE RAIN FOR THE AFTERNOON...AN ADVISORY SEEMS
TO BE THE BETTER REPLACEMENT FOR THE WATCH RIGHT NOW. DURING THE
OVERNIGHT HOURS...THE PRECIPITATION SHOULD SLOWLY START LIFTING TO
THE NORTHEAST WITH THE SHORTWAVE. HOWEVER...PLENTY OF LOW LEVEL
STILL EXISTS. THIS BRINGS UP A CONCERN...AS ONCE THE SHORTWAVE
MOVES IN THE ICE MAY SCOUR OUT...RESULTING IN RAIN/FREEZING RAIN.
THE BEST CHANCE FOR THIS TO OCCUR IS EAST OF A LINE FROM CHARLES
CITY IOWA TO LA CROSSE AND WISCONSIN RAPIDS. DID PUT IN A FEW
HUNDREDTHS OF ICE ACCUMULATION NEAR THIS LINE. WITH THE ICE
ACCUMULATION AND TO ADD A BUFFER IN CASE THE PRECIPITATION CHANGES
TO SNOW QUICKER TONIGHT...ADDED ANOTHER ROW OF COUNTIES JUST EAST
OF THE PREVIOUS WATCH FOR AN ADVISORY. REGARDING TEMPERATURES...
INCREASED THEM BOTH TODAY AND TONIGHT GIVEN CURRENT WARMER TRENDS.
SUNDAY THROUGH MONDAY NIGHT...MUCH QUIETER TIME PERIOD. SHORTWAVE
TROUGHING DIGGING INTO MONTANA TONIGHT IS FORECAST BY ALL MODELS
TO MARCH SLOWLY EAST...REACHING THE WESTERN END OF THE FORECAST
AREA AROUND 12Z TUESDAY. ALTHOUGH THE FORECAST AREA RESIDES IN
SOUTHWEST FLOW ALOFT...ALL OF THE SHORTWAVES IN THAT SOUTHWEST
FLOW TO HELP PRODUCE PRECIPITATION LOOK TO STAY TO THE SOUTHEAST
OF HERE. IN ADDITION...THE SHORTWAVE MOVING THROUGH TONIGHT HELPS
TO SCOUR OUT MUCH OF THE MOISTURE...NOTED BY PRECIPITABLE WATER
VALUES FALLING TO 0.25 INCH OR LESS BY 21Z SUNDAY. DID MAINTAIN
SOME LOW 20-30 PERCENT CHANCES FOR THE EASTERN TWO THIRDS OF THE
FORECAST AREA ON SUNDAY...DUE TO LINGERING LOW LEVEL LIFT.
AGAIN...THE PRESENCE OF ICE IS QUESTIONABLE...ESPECIALLY OVER
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. AS A RESULT...HAVE
MENTIONED A SNOW/FREEZING DRIZZLE MIX. AFTER THAT...DRY WEATHER
WILL BE THE RULE...WITH ONLY SOME INCREASE OF MID/HIGH CLOUDS AS
THE MONTANA SHORTWAVE TROUGHING APPROACHES. BIGGER IMPACT
TEMPERATURES. 850MB TEMPS AT 12Z SUNDAY SHOULD RANGE FROM -4C EAST
TO -8C WEST. THESE COOL THROUGH THE DAY SUNDAY...SO HIGHS SHOULD
END UP CLOSE TO THE MORNING LOWS. FURTHER COOLING OF 850MB TEMPS
IS PROGGED FOR MONDAY...DROPPING TO -10 TO -14C. THEREFORE...
HIGHS IN MOST LOCATIONS LOOK TO ONLY TOP OUT IN THE 20S. MORE
TEENS AND SINGLE DIGIT READINGS ABOVE ZERO EXPECTED AT NIGHT WITH
NOCTURNAL COOLING.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
343 AM CST SAT DEC 3 2011
03.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES CONTINUE TO PAINT A
COLDER THAN NORMAL PATTERN FOR THE FORECAST AREA AS A POLAR VORTEX
SETS UP OVER HUDSON BAY BY LATE IN THE WEEK. SHORTWAVE TROUGH WILL
MOVE EAST TO WEST ACROSS THE AREA ON TUESDAY...NOT REALLY BRINGING
ANY PRECIPITATION WITH IT DUE TO LACK OF MOISTURE. HOWEVER...850MB
TEMPS FALL FURTHER...DOWN TO -11 TO -15C. BRIEF WARMING SHOULD OCCUR
TUESDAY NIGHT AS A WEAK UPPER RIDGE CROSSES IN THE WAKE OF TUESDAYS
SHORTWAVE TROUGH. THEN THIS GETS REPLACE BY A ZONAL FLOW FOR
WEDNESDAY INTO THURSDAY IN RESPONSE TO A SERIES OF SHORTWAVES
CROSSING SOUTHERN CANADA. THIS FLOW SETUP SHOULD ALLOW FOR DRY BUT
COOL CONDITIONS TO CONTINUE. ALL MODELS THEN INDICATE A DEEP
TROUGH DROPPING SOUTH THROUGH THE NORTHERN PLAINS THURSDAY NIGHT.
AHEAD OF THIS TROUGH...SOME PRECIP COULD OCCUR DUE TO DPVA AND
ISENTROPIC LIFT...THOUGH MOISTURE AGAIN IS QUESTIONABLE. INCLUDED
A 20 PERCENT CHANCE OF SNOW ACROSS THE SOUTHERN PORTIONS OF THE
FORECAST AREA...IN-LINE WITH THE 03.00Z GFS/ECMWF. THE UPPER
TROUGHING MOVES INTO THE AREA ON FRIDAY...BRINGING AIR MORE OF
ARCTIC ORIGIN ACROSS WITH 850MB TEMPS TANKING TO AROUND -20C. FOR
NOW FOLLOWED A CONSENSUS OF GUIDANCE FOR HIGHS AND LOWS THROUGHOUT
THE LONG TERM FORECAST...BUT MAY NEED TO LOWER HIGHS/LOWS FOR
FRIDAY AND FRIDAY NIGHT IF THIS -20C AT 850MB AIRMASS FORECAST
PERSISTS.
&&
.AVIATION...
1130 PM CST FRI DEC 2 2011
LOW STRATUS HAS MANIFESTED ACROSS IA IN THE PRESENCE OF LOW LEVEL
SATURATION/WARMING AND SOME MOISTURE TRANSPORT...AND HAS ADVECTED
OVER KRST/KLSE. KRST IS ON THE EDGE OF THE MVFR CEILINGS...BUT
RUC13/NAM12 SUGGESTS THAT IT SHOULD HOLD ACROSS KRST THROUGH
SATURDAY. VFR JUST TO THE WEST THOUGH...AND SEE SOME POTENTIAL FOR
AN IMPROVEMENT IN CEILINGS AT BOTH LOCATIONS FOR LATE MORNING/EARLY
AFTERNOON AS INITIAL SURGE OF MOISTURE/WARM AIR ADVECTION MOVES OFF
TO THE NORTHEAST. WILL KEEP MVFR FOR NOW...BUT IT WILL HAVE TO BE
MONITORED. MVFR/IFR THEN RETURNS TONIGHT AS THE MAIN PORTION OF THE
STORM SYSTEM MOVES IN.
FOR PCPN...TEMPS ARE WARMING MORE THAN MODELS PREVIOUSLY
SUGGESTED...AND LOOK A BIT WARMER FOR MUCH OF THE DAY SAT. SMALL
CHANGES BUT BIG IMPACTS ON PCPN TYPE. WILL ADJUST FOR ANY CHANGE
OVER TO ALL -SN TO LATER IN THE DAY AS A RESULT. IN ADDITION...NAM12
AND SOME OTHER SHORT TERM MODELS POINT TO A RELATIVE DRY PERIOD IN
THE MIDDLE PART OF THE DAY. BELIEVE THIS IS REASONABLE AND WILL TRIM
THE TAFS THIS WAY. IF SOMETHING WOULD FALL...IT SHOULD BE LIGHT. THE
HEAVY PCPN AND CHANGE OVER TO ALL SNOW WILL OCCUR LATE THIS
AFTERNOON/EARLY EVENING. VSBYS 1-2SM IN THE -SN CAN BE
EXPECTED...WITH SEVERAL INCHES OF ACCUMULATION BY SUN MORNING.
HIGHER AMOUNTS AT KRST. WINDS WILL SWING FROM THE SOUTH TO NORTHWEST
NEAR 00Z...AND COULD INCREASE OVERNIGHT. SNOW SHOULD BE WET
THOUGH...PREVENTING MUCH OF THE BLOWING/DRIFTING POTENTIAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 AM CST SAT DEC 3 2011
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR WIZ041>044-053.
FREEZING RAIN ADVISORY UNTIL 7 AM CST THIS MORNING FOR WIZ029-
032>034-041>044-053>055-061.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SUNDAY FOR
WIZ017-029-032>034.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR MNZ096.
FREEZING RAIN ADVISORY UNTIL 7 AM CST THIS MORNING FOR MNZ079-
086>088-094>096.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SUNDAY FOR
MNZ079-086>088-094-095.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR IAZ010-011-019-029.
FREEZING RAIN ADVISORY UNTIL 7 AM CST THIS MORNING FOR
IAZ008>011-018-019-029-030.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SUNDAY FOR
IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1047 PM CST FRI DEC 2 2011
.UPDATE...
THINGS ARE LOOKING ON SCHEDULE. PRECIP IS BREAKING OUT QUICKLY
ACROSS IOWA AND WILL BE CROSSING THE RIVER BY OR SHORTLY AFTER
MIDNIGHT...THEN RACING THROUGH THE REMAINDER OF THE CWA OVERNIGHT.
TEMPS DROPPED TO THEIR MINS EARLY THIS EVENING AS CLEAR SKIES AND
LOW DEWPOINTS DID THEIR JOB. BUT THICKENING CIRRUS CANOPY AND
ADVANCING LOW CLOUDS HAVE REVERSED THE TREND WITH TEMPS RISING
NOW. TEMPS SHOULD BE ABOVE FREEZING BY THE TIME THE PRECIP
ARRIVES. SOME ROAD SURFACE TEMPS MAY LINGER BELOW FREEZING
INITIALLY AND CAUSE SOME ICING FOR A BRIEF TIME. OTHERWISE...THIS
IS A RAIN EVENT. OTHER THAN INCREASING POPS LATER TONIGHT...NO
MAJOR CHANGES WERE MADE TO THE FORECAST TONIGHT.
&&
.AVIATION/06Z TAFS/...
A MIX OF MVFR/IFR CIGS ARE ADVANCING QUICKLY INTO SOUTHWEST
WISCONSIN LATE THIS EVENING AND THESE SHOULD CONTINUE RIGHT ACROSS
THE FORECAST AREA OVERNIGHT. I THINK WE/LL KEEP THE CIGS JUST
ABOVE THE IFR THRESHOLD FOR NOW...RIGHT AROUND 1200FT...BUT WE
COULD SEE SOME PERIODS OF IFR CIGS IN THE RAIN. AS STATED IN THE
EARLIER AVIATION DISCUSSION...THERE WILL BE A PERIOD OF MORNING
RAIN...FOLLOWED BY A LULL IN THE ACTIVITY DURING THE LATE MORNING
AND AFTERNOON...ESPECIALLY EAST OF KMSN. NOT CONFIDENT WE WILL SEE
CIGS IMPROVE A WHOLE LOT...BUT IT/S POSSIBLE THEY COULD LIFT TO
VFR LEVELS FOR A SHORT TIME. THEN DROP BACK DOWN AS THE COLD FRONT
SWEEPS THROUGH IN THE EVENING.
&&
.PREV DISCUSSION... /ISSUED 329 PM CST FRI DEC 2 2011/
SHORT TERM...
TONIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
SHORTWAVE ENERGY EJECTING OUT OF A TROUGH IN THE SOUTHWEST U.S. WILL
BRING A PLUME OF MOISTURE INTO WISCONSIN TONIGHT THROUGH SUNDAY
MORNING. THIS PLUME IS APPARENT IN THE LATEST WATER VAPOR IMAGERY.
THIS TROUGH/SHORTWAVE WILL PHASE WITH A NORTHERN STREAM TROUGH OVER
THE WEEKEND...CREATING A PROLONGED PRECIP EVENT ACROSS WISCONSIN.
MODELS ARE IN FAIR AGREEMENT ABOUT WAITING UNTIL AFTER MIDNIGHT FOR
THE WALL OF WATER...OR DEEP MOISTURE...TO REACH SOUTH CENTRAL WI.
WHILE THERE MAY BE SOME PRECIP IN THE FORECAST AREA BEFORE 3
AM...THE MAIN SURGE WILL HIT MOST OF THE AREA BETWEEN 3 AND 6 AM.
THE PRECIP MAY HOLD OFF IN KENOSHA AND MILWAUKEE UNTIL RIGHT AROUND
6 AM/12Z. UPPER LEVEL DIVERGENCE INCREASES TONIGHT ALONG WITH
MODERATE 700MB UPWARD MOTION. ISENTROPIC LIFT SEEN ON THE 290K
ISENTROPIC LEVEL WITH CONDENSATION PRESSURE DEFICITS BELOW 5 MB ON
THE NAM BY SUNRISE SATURDAY.
PRECIP WILL MAINLY BE IN THE FORM OF RAIN IN THE ENTIRE FORECAST
AREA. THE ONLY EXCEPTION WILL BE AROUND THE DELLS AND GREEN
LAKE/MARQUETTE COUNTIES WHERE THE EVENT COULD BEGIN AS SNOW AND
SWITCH TO RAIN. WITH THE STRONG WARM AIR ADVECTION...SFC TEMPS ARE
EXPECTED TO WARM TO JUST ABOVE FREEZING WITH THE ONSET OF
PRECIPITATION...THUS LIMITING THE FREEZING RAIN OR SNOW POTENTIAL.
THE CENTER OF THE SURFACE LOW PRESSURE WILL TRACK RIGHT ACROSS SOUTH
CENTRAL WI LATE SAT AFTERNOON INTO SUNDAY MORNING...SO A LULL IN THE
PRECIPITATION IS EXPECTED IN SOUTHEAST WI...EAST OF MADISON. THE
LULL SHOULD BE FROM AROUND 2 PM SAT THROUGH SAT EVENING IN
MILWAUKEE. CLOUD COVER DURING THIS TIME IS UNCERTAIN...AS MODELS
SUGGEST CLEARING AND EXPERIENCE SUGGESTS STRATUS CLOUDS AND POSSIBLY
LIGHT FOG.
SATURDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
THE SHORTWAVE TROUGH LIFTING NEWD THROUGH THE GREAT PLAINS WILL
REACH NRN WI BY 12Z SUN AND WILL AID IN MINOR DEEPENING OF THE SFC
LOW AS IT TRACKS FROM ERN KS TO SE WI. A DRY SLOT WILL INITIALLY
BE OVER ERN WI SAT EVENING BUT WILL SHIFT EWD WITH A 60 KT LOW
LEVEL JET STREAM TO BRING A NEW SURGE OF WARM AND MOIST ADVECTION
AND SFC-850 MB FRONTOGENESIS. PWS TO INCREASE TO 0.80-0.90 INCHES WITH
WIDESPREAD MDT RAIN EXPECTED. THE CONSENSUS OF THE THERMAL FIELDS
WILL BRING A MIXTURE OF LGT RAIN AND LGT SNOW TO THE FAR WRN CWA
BETWEEN 09-12Z. PCPN TO QUICKLY DIMINISH SUN AM AS THE LOW LEVEL
JET STREAM SHIFTS INTO LOWER MI. LIKELY POPS EXPECTED EARLY IN
THE DAY FOR THE NE CWA WITH CHANCES ELSEWHERE. LGT RAIN WILL
CHANGE TO OR MIX WITH LGT SNOW BUT SNOW ACCUMULATIONS WILL LIKELY
REMAIN UNDER ONE HALF INCH IN THE NRN AND WRN CWA WITH TRACE
AMOUNTS AT BEST IN SE WI.
COLD AND DRY ADVECTION AND SUBSIDENCE SHOULD BE ENOUGH FOR CLOUD
COVER TO BECOME FEW-SCATTERED FOR SUN NT INTO MONDAY. A WEAKENING
LOW PRESSURE AREA AND SHORTWAVE TROUGH WILL THEN MOVE FROM THE NRN
PLAINS INTO THE GREAT LAKES FOR MONDAY. THE ONLY RESULT WILL BE A
DRY COLD FRONT WITH THE UPSTREAM POLAR HIGH OVER THE NRN AND
CENTRAL GREAT PLAINS.
LONG TERM...
TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
A HIGH PRESSURE RIDGE ASSOCIATED WITH THE POLAR HIGH OVER THE
CENTRAL PLAINS WILL MOVE ACROSS WI FOR TUE/TUE NT WHILE A LONG
WAVE UPPER TROUGH AND SFC TROUGH BRINGS PCPN TO SRN AND ERN UNITED
STATES. FOR THE REMAINDER OF THE WEEK A STRONG AND VERY LARGE
CYCLONE WILL MOVE ACROSS NRN CANADA AND OCCLUDE OVER AND NORTH OF
THE HUDSON BAY AREA LATER IN THE WEEK. THE NRN USA WILL BE ON THE
SRN FRINGES OF THIS CYCLONE WITH DRY WNWLY WINDS AND GRADUAL COLD
ADVECTION. DURING THIS TIME A 1040 MB ARCTIC HIGH WILL SLIDE SWD
ALONG THE LEE OF THE CANADIAN ROCKIES AND EVENTUALLY INTO THE MID
MO RIVER VALLEY ON FRI. SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED
LATER NEXT WEEK WITH THE LACK OF SNOW COVER INHIBITING GREATER
COOLING.
AVIATION/00Z TAFS/...
CLEAR SKIES THROUGH THE EVENING UNDER THE HIGH PRESSURE. HOWEVER
SOUTH WINDS DEVELOPING AHEAD OF LOW PRESSURE FROM WESTERN OKLAHOMA
TO MINNESOTA WILL BRING INCREASING/THICKENING AND LOWERING HIGH/MID
LEVEL CLOUDS THIS EVENING...FOLLOWED BY MVFR/IFR CIGS AND VSBYS...
ESPECIALLY IN SOUTH CENTRAL WISCONSIN DURING THE EARLY MORNING HOURS
SATURDAY. SOME FREEZING RAIN POTENTIAL MAINLY NORTH AND WEST OF
MADISON TO NEAR FOND DU LAC.
THERE WILL BE A LULL IN THE PRECIP SAT AFTERNOON. NOT SURE IF
CEILINGS WILL TANK WITHIN THE LULL AS THE SFC LOW MOVES OVERHEAD
DURING THIS TIME. LOW CIGS EXPECTED EARLY SAT EVENING...WHICH SHOULD
COME UP A BIT WHEN THE NEXT ROUND OF PRECIP HITS. PRECIP TYPE SHOULD
BE ALL RAIN FROM TONIGHT THROUGH SATURDAY NIGHT AT ALL TAF SITES.
LOW LEVEL WIND SHEAR EXPECTED TONIGHT INTO SATURDAY MORNING AS LOW
LEVEL JET MOVES OVERHEAD. NAM IS STRONGER WITH THE WINDS THAN THE
GFS...AND RUC IS IN BETWEEN. LLWS WILL BE POSSIBLE ONCE AGAIN SAT
NIGHT AS A NEW SURGE OF WARM AIR ADVECTION MOVES INTO SOUTHEAST WI.
MARINE...
SOUTH WINDS WILL INCREASE TONIGHT AND WINDS AND WAVES ARE EXPECTED
TO REACH LOWER-END SMALL CRAFT ADVISORY CONDITIONS LATE TONIGHT INTO
SATURDAY. WINDS AND WAVES WILL BE HIGH THROUGH SATURDAY
MORNING...THEN THERE WILL BE A LULL IN THE WINDS SATURDAY AFTERNOON
AS THE SURFACE LOW CROSSES SOUTHEAST WISCONSIN. WEST WINDS WILL
INCREASE BEHIND THE LOW ONCE AGAIN SAT NIGHT THROUGH AT LEAST MIDDAY
SUNDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FROM 06Z TONIGHT THROUGH
18Z SUNDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON CST SUNDAY FOR LMZ643>646.
&&
$$
UPDATE...DAVIS
TONIGHT/SATURDAY AND AVIATION/MARINE...MRC
SATURDAY NIGHT THROUGH FRIDAY...GEHRING
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
316 AM MST SAT DEC 3 2011
.SHORT TERM...TODAY THROUGH MONDAY...RELATIVELY ACTIVE IN THE
SHORT TERM THIS WEEKEND AND INTO EARLY NEXT WEEK WITH SEVERAL
IMPACTS ACROSS SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.
SNOW EARLY THIS MORNING IS STARTING TO TAPER OFF TO LIGHT FLURRIES
WEST OF THE LARAMIE RANGE WITH VISIBILITIES AT RAWLINS AND
ARLINGTON INCREASING AT 2 AM. MOST OF THE LARAMIE VALLEY STRUGGLED
WITH PERSISTENT SNOWFALL LAST NIGHT...DUE TO A SNOW SHADOW EFFECT
OFF THE LARAMIE RANGE AND AN EASTERLY WIND. THEREFORE...CANCELLED
THE WINTER STORM WARNING FOR I-80 BETWEEN LARAMIE AND RAWLINS
INCLUDING THE SNOWY RANGE AND REPLACED IT WITH A WINTER WEATHER
ADVISORY UNTIL 6 AM. SNOTEL OBSERVATIONS SHOW MAINLY BETWEEN 4 TO 8
INCHES OF SNOWFALL IN THE SOUTHERN LARAMIE RANGE AND SNOWY RANGE
WITH SNOWFALL RATES BECOMING MUCH LIGHTER EARLY THIS MORNING.
GUSTY WINDS WERE ALSO NOT MUCH OF A FACTOR WITH A FEW LOCALIZED
AREAS REPORTING GUSTS UP TO 25 MPH AT TIMES. IF CURRENT TRENDS
CONTINUE...MAY NEED TO CANCEL MOST OF THE WINTER WEATHER ADVISORY
BY SUNRISE WITH KCYS RADAR LOOP SHOWING A GRADUAL LOWERING OF
REFLECTIVITY. IT APPEARS THE CHEYENNE AREA DID BETTER THAN
PREVIOUSLY EXPECTED WITH REPORTS OF 4 INCHES OF SNOW AROUND THE
AREA AT 2 AM. IR SATELLITE LOOP CONTINUES TO SHOW COOLER CLOUD
TOPS ACROSS EXTREME SOUTHEAST WYOMING AND SOUTHWEST NEBRASKA...SO
EXPECT PERIODS OF LIGHT SNOW TO CONTINUE EAST OF THE SOUTHERN
LARAMIE RANGE. SNOW WILL CONTINUE TO TAPER OFF ELSEWHERE THIS
MORNING WITH LITTLE ADDITIONAL ACCUMULATION. TEMPERATURES TODAY
WILL BE MUCH COLDER COMPARED TO YESTERDAY...WITH HIGHS STRUGGLING
TO REACH THE LOW TO MIDDLE 20S. EVEN COLDER TEMPERATURES ARE
EXPECTED BY SUNDAY AND MONDAY.
MODELS SHOW THE NEXT COLD FRONT WITH MODIFIED ARCTIC AIR PUSHING
SOUTHWARD INTO THE FORECAST AREA ON SUNDAY. LOW TEMPERATURES
SUNDAY MORNING WITH BE QUITE COLD AND IN THE SINGLE DIGITS OVER
THE HIGH PLAINS AND ZERO TO 10 BELOW ZERO WEST OF THE LARAMIE
RANGE. WINDS WILL INCREASE SLIGHTLY AHEAD OF THIS NEXT COLD
FRONT...WITH BITTERLY COLD WIND CHILL TEMPERATURES POSSIBLE ACROSS
SOUTHEAST WYOMING AS SOME AREAS DROP TO -20. THIS FRONT WILL
QUICKLY MOVE SOUTHWARD ACROSS THE AREA AND INTO COLORADO THROUGH
THE DAY ON SUNDAY...WITH ANOTHER CHANCE OF LIGHT SNOW AND
TEMPERATURES LIKELY LOWERING INTO THE SINGLE DIGITS IN THE
AFTERNOON AFTER MORNING HIGHS IN THE TEENS AND 20S. ANOTHER ONE TO
THREE INCHES OF SNOW IS POSSIBLE MAINLY ACROSS SOUTHEAST
WYOMING...BUT DO NOT EXPECT MODERATE OR SIGNIFICANT ACCUMULATIONS
SINCE THE AIR WILL BE VERY COLD AND WILL NOT CONTAIN MUCH
MOISTURE. TEMPERATURES SUNDAY NIGHT AND MONDAY WILL BE VERY
COLD...WITH LOWS LIKELY BELOW ZERO ACROSS THE MAJORITY OF THE
FORECAST AREA FROM RAWLINS EASTWARD TO THE PANHANDLE OF NEBRASKA.
HIGH TEMPERATURES ON MONDAY WILL STRUGGLE TO REACH THE MIDDLE
TEENS WITH 700MB TEMPERATURES BELOW -20C THROUGH THE DAY. ONE
POSSIBLE CONCERN IS SUNDAY NIGHT WITH MODELS SHOWING A BRISK
NORTHERLY WIND BETWEEN 10 TO 20 MPH. THIS MAY RESULT IN WIND
CHILLS VALUES AROUND -30 WHICH MEET WIND CHILL WARNING CRITERIA.
MONDAY WILL BE DRIER...SO LOWERED POP BELOW 10 PERCENT DURING THE
DAY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...00Z ECMWF/00Z GFS/GEFS
CONSENSUS MAINTAINS A HIGHLY AMPLIFIED MID/UPPER LEVEL PATTERN OVER
NORTH AMERICA THROUGH THE PERIOD. THE MAIN FEATURES WILL BE RIDGES
ANCHORED OVER THE NORTH ATLANTIC AND NORTHEAST PACIFIC...WITH A MEAN
LONG WAVE TROUGH ENCOMPASSING MOST OF THE LOWER 48 STATES. ONE
SHORT WAVE TROUGH WILL BE MOVING EAST THROUGH THE PLAINS AND MIDWEST
ON TUESDAY...REPLACED BY A NORTHEAST-SOUTHWEST SHORT WAVE RIDGE AXIS
PASSING SOUTHEAST ACROSS THE CWA TUESDAY NIGHT. A RATHER DEEP VORTEX
THEN TAKES RESIDENCE NEAR HUDSON BAY CANADA WITH A TROUGH AXIS
EXTENDING THROUGH THE CENTRAL AND SOUTHERN ROCKIES THURSDAY...AND
PLAINS ON FRIDAY. AFTER A VERY COLD MONDAY NIGHT/TUESDAY MORNING
WITH LOWS FROM 5 ABOVE TO 15 BELOW...SURFACE HIGH PRESSURE WILL
BECOME CENTERED WEST OF THE CONTINENTAL DIVIDE...WITH A LEE TROUGH
DEVELOPING ALONG THE FRONT RANGE TUESDAY. THIS TROUGH WILL MOVE
EAST INTO THE CENTRAL HIGH PLAINS ON WEDNESDAY...WITH A CANADIAN
COLD FRONT APPROACHING FROM THE NORTH. IT WILL BE MILDER AND BREEZY
BOTH DAYS DUE TO DOWNSLOPING FLOW OFF THE LARAMIE RANGE. HIGHS IN
THE 20S AND 30S TUESDAY WILL RISE INTO THE 30S AND 40S ON WEDNESDAY.
THE COLD FRONT WILL SINK SOUTH THROUGH THE CWA ON THURSDAY WITH
SOME LIGHT SNOW DEVELOPING. THE AIRMASS BEHIND THIS FRONT WILL BE
MODIFIED CONTINENTAL ARCTIC...SO TEMPERATURES WILL NOT BE AS COLD.
THE SNOW WILL END BY FRIDAY MORNING AS HIGH PRESSURE BUILDS SOUTH
INTO THE NORTH CENTRAL ROCKIES AND HIGH PLAINS. BELOW NORMAL
TEMPERATURES FRIDAY WILL MODERATE TO NEAR NORMAL SATURDAY AS LEE
TROUGHING DEVELOPS EAST OF THE LARAMIE RANGE WITH BREEZY DOWNSLOPING
WINDS.
&&
.AVIATION...06Z TAF ISSUANCE...IFR/LIFR CONDITIONS TO CONTINUE
OVERNIGHT WITH LIGHT SNOW. SNOW WILL COME TO AN END BY MID MORNING.
LATEST HRRR GUIDANCE KEEPS IFR GOING FOR OUR WYOMING AIRPORTS
THROUGH 15Z OR SO WITH THE NORTHERN PANHANDLE STAYING VFR.
&&
.FIRE WEATHER...NO FIRE WEATHER CONCERNS THIS WEEKEND AND EARLY
NEXT WEEK. SEVERAL STRONG COLD FRONTS WILL PUSH ACROSS THE AREA
RESULTING IN PERIODS OF LIGHT SNOW AND VERY COLD TEMPERATURES.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY UNTIL 6 AM SATURDAY FOR WYZ103-WYZ104-
WYZ105-WYZ106-WYZ107-WYZ109-WYZ111-WYZ112-WYZ113.
WINTER WEATHER ADVISORY UNTIL 2 PM SATURDAY FOR WYZ110-WYZ114-
WYZ115-WYZ116-WYZ117-WYZ118.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...TJT
LONG TERM/AVIATION...MAJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1015 PM MST FRI DEC 2 2011
.AVIATION...06Z TAFS
IFR/LIFR CONDITIONS TO CONTINUE OVERNIGHT WITH LIGHT SNOW. SNOW
WILL COME TO AN END BY MID MORNING. LATEST HRRR GUIDANCE KEEPS IFR
GOING FOR OUR WYOMING AIRPORTS THROUGH 15Z OR SO WITH THE NORTHERN
PANHANDLE STAYING VFR.
CLAYCOMB
&&
.PREV DISCUSSION... /ISSUED 834 PM MST FRI DEC 2 2011/
UPDATE...
GETTING NEW SNOW REPORTS OUT OF RAWLINS WITH 3 INCHES OF NEW SNOW ALREADY
THIS EVENING. LATEST SATELLITE IMAGERY CONTINUES TO SHOW COOLING
AND EXPANDING COLD CLOUD TOPS OVER CARBON COUNTY. LATEST NAM
SHOWING SOME BANDING OF SNOW WITH ADDITION 3-5 INCHES OF SNOW
POSSIBLE OUT THAT WAY. WENT AHEAD WITH AN UPGRADE TO THE SNOW
ADVISORIES TO A WINTER STORM WARNING FOR THE I80 CORRIDOR FROM
LARAMIE TO RAWLINS. LATEST WRF.NAM ALSO SHOWING HIGHER SNOW
AMOUNTS OVER LARAMIE COUNTY OVERNIGHT...SO WENT AHEAD AND EXPANDED
THE SNOW ADVISORY FURTHER EAST TO COVER LARAMIE AND PLATTE
COUNTIES. UPDATES HAVE BEEN SENT.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 315 PM MST FRI DEC 02 2011/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT.
TONIGHT...NEXT SHORTWAVE TROUGH MOVES ACROSS OVERNIGHT AFTER ANOTHER
COLD FRONTAL SURGE. LOOKS LIKE ENOUGH DYNAMICAL LIFT COMBINED WITH
UPSLOPE TO PRODUCE WIDESPREAD LIGHT TO MODERATE SNOW WEST OF A
DOUGLAS TO KIMBALL LINE. WITH PROGGED QPFS ON THE NAM AND GFS AS
WELL AS EXPECTED SNOWFALL RATIOS OF 15 TO 1 IN THE COLD AIRMASS...AS
WELL AS THE HPC SNOWFALL GUIDANCE...WE ANTICIPATE LOW END WINTER
WEATHER ADVISORIES ROUGHLY WEST OF A DOUGLAS TO CHEYENNE LINE WITH
THE SNOWFALL EVENT ENDING BY EARLY SATURDAY AFTERNOON. FORTUNATELY...
WINDS WILL BE RELATIVELY LIGHT...THUS MINIMAL BLOWING AND DRIFTING
OF THE SNOW.
SATURDAY...SNOW WILL GRADUALLY END AND DISSIPATE FROM NORTH TO SOUTH
AS THE SHORTWAVE TROUGH ALOFT MOVES OVER COLORADO AND MOISTURE AND
LIFT WANE. COLDER DAY IN THE WAKE OF THE COLD FRONT WITH HIGH
TEMPERATURES IN THE TEENS AND 20S WITH 700 MB TEMPERATURES NEAR -14
CELSIUS.
SATURDAY NIGHT...ALBERTA CLIPPER SHORTWAVE TROUGH ALOFT MOVES
SOUTHEAST ACROSS MONTANA AND NORTH DAKOTA...INDUCING SURFACE LOW
PRESSURE ACROSS WESTERN NORTH DAKOTA. DECENT SURFACE THROUGH 700 MB
GRADIENTS DEVELOP THUS WILL SEE SOME AREAS OF BLOWING SNOW CAUSED BY
WINDS PICKING UP ALONG AND WEST OF INTERSTATE 25 IN TYPICALLY WIND
PRONE AREAS.
SUNDAY...ANOTHER REINFORCING SHOT OF COLD AIR MOVES ACROSS OUR
COUNTIES IN THE WAKE OF A COLD FRONT. NEXT SHORTWAVE TROUGH ALOFT
AND ADEQUATE LOW AND MID LEVEL MOISTURE WILL PRODUCE LIGHT TO
MODERATE SNOW ACROSS OUR WYOMING COUNTIES...ESPECIALLY WEST OF
INTERSTATE 25. EXPECT SNOWFALL AMOUNTS OF 1 TO 2 INCHES AT LOWER
ELEVATIONS WITH 3 TO 5 INCHES OVER THE SNOWY AND SIERRA MADRE RANGES.
SUNDAY NIGHT...SNOW SHOWERS WILL DECREASE IN AREAL COVERAGE AS THE
UPPER TROUGH MOVES ACROSS COLORADO AND LIFT DECREASES. COLD NIGHT
WITH THE MOTHERLODE 700 MB TEMPERATURES NEAR -22 CELSIUS OVERHEAD
THOUGH LOOKS LIKE ENOUGH CLOUD COVER WILL ACT AS A BLANKET TO LIMIT
POTENTIAL LOW TEMPERATURES.
LONG TERM...MONDAY THROUGH FRIDAY...
EXTENDED FORECAST PERIOD TO START OUT ON THE QUIET SIDE. EXPANSIVE
UPPER RIDGE WILL BUILD ACROSS THE NORTHWEST UNITED STATES STARTING
EARLY NEXT WEEK. FOLLOWING A COLD WEEKEND...WARM AIR WILL SPREAD
INTO THE AREA AS THE RIDGE BUILDS. SNOW COVER OVER THE AREA WILL
KEEP TEMPERATURES FROM REACHING THEIR FULL POTENTIAL BUT SHOULD
EASILY SEE HIGH TEMPERATURES BACK INTO THE 30S TUESDAY EAST OF THE
LARAMIE RANGE...AND POSSIBLY SOME 40S SHOULD WESTERLY DOWNSLOPE IN
PLACE. WEDNESDAY SHOULD BE THE WARMEST DAY OF THE WEEK WITH 40S
EAST. INCREASED TEMPERATURES OVER THE CONSENSUS GUIDANCE WEDNESDAY
BUT EVEN THIS MAY NOT BE WARM ENOUGH UNDER WESTERLY FLOW AND 700 MB
TEMPERATURES APPROACHING ZERO DEGREES CELSIUS. DRY MONDAY THROUGH
WEDNESDAY BUT SMALL CHANCES FOR SNOW RETURN THE LAST PORTIONS OF THE
WEEK. UPPER TROUGH TO DIG INTO THE NORTHERN PLAINS LATE NEXT WEEK.
THE QUESTION IS HOW FAR SOUTH AND WEST THIS FEATURE WILL MAKE IT.
LATEST GFS AND EC BOTH KEEP THE BUILD OF THE SHORTWAVE ENERGY MOVING
THROUGH THE UPPER TROUGH NORTH OF THE FORECAST AREA...SO MAY STAY DRY
ALL NEXT WEEK.
FIRE WEATHER...NO FIRE WEATHER CONCERNS. SNOW TO SPREAD ACROSS MOST
OF THE FIRE WEATHER FORECAST AREA TONIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 5 AM SATURDAY FOR WYZ109-WYZ110-
WYZ113-WYZ114-WYZ115.
WINTER WEATHER ADVISORY UNTIL 2 PM SATURDAY FOR WYZ103-WYZ104-
WYZ105-WYZ106-WYZ107-WYZ111-WYZ112-WYZ116-WYZ117-WYZ118.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM/AVIATION...LIEBL
AREA FORECAST DISCUSSION
NWS DENVER CO
1149 PM MST SUN DEC 4 2011
.UPDATE...HAVE DECIDED TO CANCEL THE REMAIN PORTION OF THE WINTER
WEATHER ADVISORY. RADAR COVERAGE CONTINUES TO SHRINK FROM NORTH TO
SOUTH ACROSS THE DENVER AREA. ANY ADDITIONAL ACCUMULATIONS WILL BE
SOUTH OF THE DENVER AREA AND LESS THAN AN INCH.
&&
.AVIATION...SHUD SEE ANY LINGERING SNOWFALL AROUND THE DENVER AREA
DIMINISH BY 09Z...WITH A GRADUAL IMPROVEMENT IN THE CIGS THROUGH
THE EARLY MORNING HOURS. COULD SEE CIGS OF 4-5 KFT IMPROVE SOONER
THAN IS REFLECTED IN THE CURRENT TAFS WHICH SHOWS THOSE CIGS IN
PLACE UNTIL 18Z...THOSE TRENDS MAY NEED TO BE SPED UP ON THE NEXT
TAF ISSUANCE.
&&
.PREV DISCUSSION... /ISSUED 803 PM MST SUN DEC 4 2011/
UPDATE...
SHORT TERM...LATEST DATA SUGGEST BEST CHANCE FOR ACCUMULATING
SNOWS OVERNIGHT WILL BE MAINLY FROM DENVER SOUTH TO THE PALMER
DIVIDE AND OVER THE SRN FOOTHILLS AND PARK COUNTY. HAD A BURST OF
HEAVIER SNOW FM LATE AFTN INTO THE EARLY EVENING HOURS WHICH
PRODUCED FROM 3 TO 6 INCHES OF SNOW IN THE SRN FOOTHILLS INTO PARK
COUNTY. WILL LEAVE ADVISORIES IN PLACE FOR THE DENVER METRO AREA
BUT SNOW AMOUNTS LOOK TO BE MORE IN THE 2 TO 3 INCH RANGE. FURTHER
NORTH AND EAST SNOW POTENTIAL DOES NOT LOOK THAT GREAT SO WILL
DROP ADVISORIES IN THE NRN FOOTHILLS AND IN THE FORT COLLINS AND
GREELEY AREAS.
AVIATION...RIGHT NOW SNOW AMOUNTS AT DIA AND BJC SHOULD BE IN
THE 1 TO 2 INCH RANGE WITH UP TO 3 INCHES AT APA. LATEST DATA
SUGGEST LIGHT SNOW WILL GRADUALLY END BY 2 AM OR 3 AM AT DIA WITH
ONLY FLURRIES THROUGH SUNRISE.
PREV DISCUSSION... /ISSUED 250 PM MST SUN DEC 4 2011/
SHORT TERM...BROAD UPPER TROF COVERS MUCH OF THE WESTERN U.S. WHILE
WATER VAPOR IMAGERY SHOWING NEXT DISTURBANCE DROPPING SOUTH INTO THE
MEAN TROF POSITION OVER UTAH. RUC QG FIELDS SHOWING BEST UPWARD
FORCING OVER WESTERN CO AND WESTERN WYOMING. THE ASSOCIATED COLD
FRONT IS MOVING SOUTH FROM SOUTHERN WYOMING INTO NORTHERN COLORADO
WITH GUSTY NORTHERLY WINDS DEVELOPING BEHIND THE FRONT. CEILINGS ARE
BEGINNING TO LOWER OVER THE FRONT RANGE WITH SOME VERY LIGHT ECHOES
DEVELOPING OVER THE FOOTHILLS. OVERALL...FORECAST IS STILL ON TRACK
WITH MAIN CONCERN SNOW AMOUNTS FOR UPCOMING STORM. SNOW AMOUNTS
EXPECTED TO BE A BIT LOWER THAN THE LAST STORM...AS QG VERTICAL
VELOCITY FIELDS SHOWING THE BEST FORCING ACROSS WESTERN COLORADO
WITH LESSER FORCING OVER NORTHEAST COLORADO AND OVERALL MOISTURE IS
A BIT LOWER. HIGHEST SNOW AMOUNTS WILL BE OVER THE EAST SLOPE FRONT
RANGE FOOTHILLS WITH LESSER AMOUNTS AS YOU MOVE EAST AWAY FROM THE
FOOTHILLS. THERE IS SOME GOOD LOW LEVEL INSTABILITY WITH UPSLOPE UP
TO AROUND 600MB. WILL KEEP THE CURRENT 3-6 SNOWFALL RANGE OVER THE
URBAN CORRIDOR BUT WOULDN`T BE SURPRISED IF AMOUNTS END UP BEING A
BIT LOWER. BIG DROPOFF OF SNOW EAST OF INTERSTATE 25 AND AM
CONCERNED THAT THERE WON`T BE MUCH SNOW OVER EASTERN WELD COUNTY AND
ZONE 45 AND 46 WITH CURRENT ADVISORIES. WILL LEAVE IN PLACE FOR NOW.
FOR THE FOOTHILLS WILL STILL GO WITH 5 TO 10 INCHES. EVEN COLDER
TEMPERATURES FOR TONIGHT AND MONDAY WITH READINGS IN THE SINGLE
DIGITS AND LOWER TEENS FOR THE NEXT 24 HOURS.
LONG TERM...COULD STILL SEE A FEW FLURRIES OCCURRING SOUTH ON
INTERSTATE 70 AS THE STORM CONTINUES TO MOVE SOUTH AND COLD HIGH
PRESSURE SETTLES IN. TEMPERATURES WILL CONTINUE TO PLUMMET TO BELOW
ZERO ACROSS THE AREA. WILL LIKELY SEE VERY COLD TEMPERATURES IN THE
HIGH MOUNTAIN VALLEYS...DROPPING TO AROUND -20 TO -30 BY EARLY
TUESDAY MORNING.
THE PERSISTENT UPPER TROUGH WILL FINALLY MOVE SOUTHEAST OF THE AREA
WITH A SHORT WAVE UPPER RIDGE MOVING OVERHEAD HOWEVER FLOW ALOFT
WILL STILL BE NORTHERLY. TEMPERATURES WILL WARM SLIGHTLY...BUT HAVE
KEPT TEMPERATURES COOLER THAN GUIDANCE AS THE RECENT COLD AIRMASS
WILL BE HARD TO SCOUR OUT AND THE SNOW ON THE GROUND WILL LIKELY
HAVE AN AFFECT AS WELL. HAVE KEPT HIGHS IN THE TEENS TO UPPER 20S
FOR TUESDAY. ON WEDNESDAY...FLOW ALOFT WILL TURN WESTERLY AS A BROAD
UPPER TROUGH OVER CANADA DROPS SOUTH. THE WEST WINDS WILL HELP
TEMPERATURES WARM DURING THE DAY...THEN A WEAK COLD FRONT WILL DROP
SOUTH DURING THE NIGHT. NO REAL PRECIPITATION EXPECT THAT
NIGHT...HOWEVER IT WILL RESULT IN COOLER TEMPERATURES AND A SLIGHT
CHANCE OF SNOW THURSDAY AS ANOTHER SHORTWAVE TROUGH ROUNDS THE
BOTTOM OF THE LARGER TROUGH.
THE LARGE SCALE PATTERN WILL CONTINUE TO TRANSITION EAST FRIDAY TO
BRING A STRONGER UPPER RIDGE OVER THE ROCKIES BRINGING DRIER WEATHER
AND RELATIVELY WARMER AIR FRIDAY AND SATURDAY. INTRODUCING A SLIGHT
CHANCE OF PRECIPITATION FOR SUNDAY AS MODELS DISAGREEING ON WHETHER
THERE WILL BE ANOTHER TROUGH OR RIDGE OVER THE AREA.
AVIATION...CEILINGS BEGINNING TO LOWER NORTH OF THE LOCAL TERMINALS
WITH CIGS OF 5000-7000 FEET AGL UPSTREAM OVER FNL AND GXY. THIS WILL
RESULT IN ILS APPROACHES AROUND 23Z AT DEN AND BJC. THE LIGHT SNOW
NOT FAR BEHIND WITH SNOW NOW AT CYS. MORE WIDESPREAD SNOW AT LOCAL
AIRPORTS DEVELOPING BETWEEN 02-3Z AND CONTINUING THROUGH ABOUT 08Z.
THIS WILL BE THE WINDOW OF MOST OF THE ACCUMULATION SNOW. MOST OF
THE SNOW WILL BECOME VERY LIGHT AND JUST FLURRIES DURING THE DAY ON
MONDAY WITH ACCUMULATIONS UNDER AN INCH. STILL TOTAL ACCUMULATIONS
OF 3 TO 6 INCHES...WITH 2-3 AT DIA...3-4 AT APA AND 4 TO 6 AT BJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....MEIER
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
116 AM EST MON DEC 5 2011
.SYNOPSIS...
HIGH PRESSURE DOMINATES THE MID ATLANTIC REGION TODAY. A COLD FRONT
MOVES INTO THE REGION FROM THE WEST LATE TUESDAY. LOW PRESSURE
RIDES NORTHWARD ALONG THE FRONT WEDNESDAY INTO THURSDAY. HIGH
PRESSURE RETURNS LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS HIGH PRESSURE MOVES SLOWLY OFF THE COAST...LIGHT WINDS ARE
BECOMING SOUTHEAST AND SOUTH...BRINGING INCREASING MOISTURE TO THE
AREA. AS OF 05Z...AREAS OF FOG COVERED THE EASTERN SHORE AND
PORTIONS OF COASTAL SOUTHEAST VIRGINIA AND NORTHEAST NORTH
CAROLINA. SOME AREAS HAVE VISIBILITY UNDER ONE HALF MILE. INLAND
AREAS...THE FOG HAS BEEN INTERMITTENT. RUC AND NAM CONTINUE TO
INDICATE FOG DEVELOPING ACROSS THE CWA...MOST WIDESPREAD EAST OF
I95. SPS ISSUED FOR THE LOWER EASTERN SHORE AND VA EAST OF I95.
NO SIGNIFICANT CHANGE TO THE LOW TEMPERATURES WHICH ARE EXPECTED
TO RANGE FROM THE UPR 30S AND LOWER 40S WEST OF I95 AND THE 40S TO
NEAR 50 ALONG THE COAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
THE UPR RIDGE JUST OFFSHORE WILL GRADUALLY GET SHOVED EASTWARD
THROUGH TUESDAY IN RESPONSE TO A BROAD UPPER TROUGH DIGGING INTO
THE CENTER OF THE NATION. BY LATE TUESDAY...THE UPR TROUGH WILL
PUSH A COLD FRONT TOWARD THE MID-ATLANTIC REGION WITH THIS
FEATURE SAGGING SOUTHWARD THROUGH VA AND INTO NE NC BY 12Z WED. AS
THE UPR TROUGH CONTINUES TO DIG AND A CUTOFF LOW DEVELOPS OVER THE
SOUTHERN PLAINS/LOWER MS VALLEY ON WED...THE FRONT WILL STALL OUT
ACROSS THE CAROLINAS WITH SFC LOW PRESSURE DEVELOPING ALONG IT.
UNFORTUNATELY...CONFIDENCE IN THE FORECAST BY WEDNESDAY IS LOW
GIVEN THE LARGE SPREAD IN THE MODELS AT THAT TIME...SO HAVE NOT
GONE HIGHER THAN 50% POP FOR TUESDAY NIGHT AND WEDNESDAY. IN THE
MEANTIME...MOISTURE WILL CONTINUE TO INCREASE FROM MONDAY INTO
TUESDAY ALLOWING FOR MOSTLY CLOUDY CONDITIONS. WILL KEEP DRY WX IN
THE FORECAST THROUGH MONDAY EVENING...BEFORE ADDING LOW CHC POPS
INTO WESTERN AREAS BY EARLY TUESDAY MORNING. AS THE FRONT NEARS ON
TUESDAY...WILL SEE CHC POPS (30-40%) SPREAD EASTWARD. HIGHEST POPS
(~50%) AGAIN WILL BE TUESDAY NIGHT/WEDNESDAY AS THE FRONT STALLS
JUST SOUTH OF OUR CWA. HIGHS MONDAY/TUESDAY IN THE 60S...EXCEPT
AROUND 70 IN THE VA TIDEWATER/NE NC. WEDNESDAY`S HIGHS WILL DEPEND
OF PCPN COVERAGE BUT SHOULD BE IN THE MID 50S NW TO THE LOW 60S SE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LO CONFIDENCE FCST MIDWEEK...HV CHOSEN TO GO CLSR TO COMBO OF
SREF/ECMWF SOLN WRT FNT PLCMNT AND EVENTUAL SFC LO PRES DVLPMNT/MVG
WED NGT INTO THU. THAT WOULD HV MNLY N WNDS...AND WDSPRD CVRG OF RA
(FOR NOW CAPPING POPS AT 50% OVR MOST OF THE FA). LO PRES XPCTD TO
MV OUT TO SEA THU NGT...W/ DRYING/SEASONABLY COLD WX FM FRI THROUGH
NEXT WKND. ACCOMPANYING THE ARRIVAL OF THE COLD AIR WL BE GUSTY NW
WNDS THU NGT INTO FRI.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
IFR/LIFR CONDITIONS WILL PREVAIL THROUGH THE OVERNIGHT ACROSS ERN
VA AND NERN NC...WITH THE WEAK SE (ONSHORE) FLOW AND THUS MSTR
ADVECTION INTO THE SFC-1000 MB LAYER. THE FOG HAS BEGUN TO LIFT
OVER THE PAST FEW HOURS OVER NERN NC...COINCIDING WITH AN
EXPANDING STRATO-CU DECK OFF THE OCEAN (BASES 5-7KFT). OVER TIME
AS THE STRAO-CU DECK SPREADS SLOLY NORTHWARD ON THE BACKSIDE OF
THE SFC HIGH...EXPECT THE TREND OF IMPROVING VSBYS TO CONTINUE
FARTHER NORTH (TO INCLUDE KORF/KPHF BY 8-10Z)...GIVEN THE
WEAKENING RADIATIONAL COOLING COMPONENT.
CONDITIONS WILL BE SLOWER TO IMPROVE OVER THE LOWER ERN SHORE...
WHERE THE FOG/STRATUS IS EXPECTED TO HANG ON UNTIL 14-16Z.
OUTLOOK...THE NEXT CHANCE FOR RAIN COMES MID-WEEK WITH THE
APPROACH OF A SLOW MOVING COLD FRONT.
&&
.MARINE...
SFC HI PRES OFFSHR RMNS IN CONTROL OVR THE WTRS THROUGH ERY PART OF
THE WK. SE TO S WNDS AOB 10 KT XPCTD THROUGH MON...W/ GRDL INCRS IN
SPDS MON NGT INTO TUE. SLO MVG CDFNT APPROACHES FM THE WNW TUE/TUE
NGT...THEN XPCTD TO SETTLE OVR THE WTRS WED. GOING CLSR TO
SREF/ECMWF SOLN W/ EVENTUALLY PUSH SWD OF FNTL BNDRY ON WED. WL HV
WNDS BCM MNLY N OVR THE FA ON WED AS FNTL SETTLES INTO FA.
TRACK/INSTENSITY OF SFC LO PRES ALG THE FNT LT WED INTO THU STILL
PROBLEMATIC ATTM. MOD/STRNG NW WNDS XPCTD BEHIND DEPARTING LO
PRES LT THU INTO FRI. NO HEADLINES NEEDED THROUGH MON NGT/TUE.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDM
NEAR TERM...MAM/LSA/MAS
SHORT TERM...JDM
LONG TERM...ALB
AVIATION...JEF/LSA
MARINE...BKH
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1231 AM EST MON DEC 5 2011
.SYNOPSIS...
HIGH PRESSURE DOMINATES THE MID ATLANTIC REGION TODAY. A COLD FRONT
MOVES INTO THE REGION FROM THE WEST LATE TUESDAY. LOW PRESSURE
RIDES NORTHWARD ALONG THE FRONT WEDNESDAY INTO THURSDAY. HIGH
PRESSURE RETURNS LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS HIGH PRESSURE MOVES SLOWLY OFF THE COAST...LIGHT WINDS ARE
BECOMING SOUTHEAST AND SOUTH...BRINGING INCREASING MOISTURE TO THE
AREA. AS OF 05Z...AREAS OF FOG COVERED THE EASTERN SHORE AND
PORTIONS OF COASTAL SOUTHEAST VIRGINIA AND NORTHEAST NORTH
CAROLINA. SOME AREAS HAVE VISIBILITY UNDER ONE HALF MILE. INLAND
AREAS...THE FOG HAS BEEN INTERMITTENT. RUC AND NAM CONTINUE TO
INDICATE FOG DEVELOPING ACROSS THE CWA...MOST WIDESPREAD EAST OF
I95. SPS ISSUED FOR THE LOWER EASTERN SHORE AND VA EAST OF I95.
NO SIGNIFICANT CHANGE TO THE LOW TEMPERATURES WHICH ARE EXPECTED
TO RANGE FROM THE UPR 30S AND LOWER 40S WEST OF I95 AND THE 40S TO
NEAR 50 ALONG THE COAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
THE UPR RIDGE JUST OFFSHORE WILL GRADUALLY GET SHOVED EASTWARD
THROUGH TUESDAY IN RESPONSE TO A BROAD UPPER TROUGH DIGGING INTO
THE CENTER OF THE NATION. BY LATE TUESDAY...THE UPR TROUGH WILL
PUSH A COLD FRONT TOWARD THE MID-ATLANTIC REGION WITH THIS
FEATURE SAGGING SOUTHWARD THROUGH VA AND INTO NE NC BY 12Z WED. AS
THE UPR TROUGH CONTINUES TO DIG AND A CUTOFF LOW DEVELOPS OVER THE
SOUTHERN PLAINS/LOWER MS VALLEY ON WED...THE FRONT WILL STALL OUT
ACROSS THE CAROLINAS WITH SFC LOW PRESSURE DEVELOPING ALONG IT.
UNFORTUNATELY...CONFIDENCE IN THE FORECAST BY WEDNESDAY IS LOW
GIVEN THE LARGE SPREAD IN THE MODELS AT THAT TIME...SO HAVE NOT
GONE HIGHER THAN 50% POP FOR TUESDAY NIGHT AND WEDNESDAY. IN THE
MEANTIME...MOISTURE WILL CONTINUE TO INCREASE FROM MONDAY INTO
TUESDAY ALLOWING FOR MOSTLY CLOUDY CONDITIONS. WILL KEEP DRY WX IN
THE FORECAST THROUGH MONDAY EVENING...BEFORE ADDING LOW CHC POPS
INTO WESTERN AREAS BY EARLY TUESDAY MORNING. AS THE FRONT NEARS ON
TUESDAY...WILL SEE CHC POPS (30-40%) SPREAD EASTWARD. HIGHEST POPS
(~50%) AGAIN WILL BE TUESDAY NIGHT/WEDNESDAY AS THE FRONT STALLS
JUST SOUTH OF OUR CWA. HIGHS MONDAY/TUESDAY IN THE 60S...EXCEPT
AROUND 70 IN THE VA TIDEWATER/NE NC. WEDNESDAY`S HIGHS WILL DEPEND
OF PCPN COVERAGE BUT SHOULD BE IN THE MID 50S NW TO THE LOW 60S SE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LO CONFIDENCE FCST MIDWEEK...HV CHOSEN TO GO CLSR TO COMBO OF
SREF/ECMWF SOLN WRT FNT PLCMNT AND EVENTUAL SFC LO PRES DVLPMNT/MVG
WED NGT INTO THU. THAT WOULD HV MNLY N WNDS...AND WDSPRD CVRG OF RA
(FOR NOW CAPPING POPS AT 50% OVR MOST OF THE FA). LO PRES XPCTD TO
MV OUT TO SEA THU NGT...W/ DRYING/SEASONABLY COLD WX FM FRI THROUGH
NEXT WKND. ACCOMPANYING THE ARRIVAL OF THE COLD AIR WL BE GUSTY NW
WNDS THU NGT INTO FRI.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
FOLLOWED CLOSE TO NAM WITH RESPECT TO FOG FORMATION IN THE TAFS AND
BROUGHT VISIBILITIES TO IFR IN TEMPO GROUPS BY 03Z AT SBY ECG AND
PHF DUE TO CURRENT TRENDS AND RUC BUFKIT. KEPT VISIBILITY NO LOWER THAN
3 MILES AT ORF. BUT EVENTUALLY DROPPED THEM BELOW ONE MILE
PREDOMINANTLY AT RIC SBY AND PHF. THERE ARE SOME INDICATIONS IN
THE NAM BUFKIT THAT IFR VISIBILITY AT ECG MAY BE INTERMITTENT.
CONDITIONS WILL BE SLOW TO IMPROVE DUE TO DEEP INVERSION AND VERY
LIGHT SURFACE WINDS. IN THE MORNING. IFR STRATUS EXPECTED UNTIL
14-16Z AT ALL BUT ORF.
OUTLOOK...THE NEXT CHANCE FOR RAIN COMES MID WEEK WITH THE
APPROACH OF A SLOW MOVING COLD FRONT.
&&
.MARINE...
SFC HI PRES OFFSHR RMNS IN CONTROL OVR THE WTRS THROUGH ERY PART OF
THE WK. SE TO S WNDS AOB 10 KT XPCTD THROUGH MON...W/ GRDL INCRS IN
SPDS MON NGT INTO TUE. SLO MVG CDFNT APPROACHES FM THE WNW TUE/TUE
NGT...THEN XPCTD TO SETTLE OVR THE WTRS WED. GOING CLSR TO
SREF/ECMWF SOLN W/ EVENTUALLY PUSH SWD OF FNTL BNDRY ON WED. WL HV
WNDS BCM MNLY N OVR THE FA ON WED AS FNTL SETTLES INTO FA.
TRACK/INSTENSITY OF SFC LO PRES ALG THE FNT LT WED INTO THU STILL
PROBLEMATIC ATTM. MOD/STRNG NW WNDS XPCTD BEHIND DEPARTING LO
PRES LT THU INTO FRI. NO HEADLINES NEEDED THROUGH MON NGT/TUE.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDM/MAS
NEAR TERM...MAM/LSA/MAS
SHORT TERM...JDM
LONG TERM...ALB
AVIATION...JEF/LSA
MARINE...ALB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
502 AM EST MON DEC 5 2011
.DISCUSSION...
RECENT RADAR IMAGES ARE STARTING TO SHOW SOME ORGANIZATION TO THE
LES...ESPECIALLY JUST OFFSHORE OF MARQUETTE COUNTY AS WELL AS A
CONVERGENCE BAND JUST OFFSHORE NEAR SAXON HARBOR. WITH GENERAL LIGHT
WINDS ACROSS THE INLAND AREAS...STRONG LAND BREEZES HAVE DEVELOPED
THAT HAS HELPED THESE BANDS TO FORM. THE MAIN PROBLEM IS THAT LES
POTENTIAL IS STILL VERY UNCLEAR TODAY. IN A GENERAL SENSE...THE LES
IS HAVING A HARD TIME DEVELOPING THIS MORNING DESPITE 850MB TEMPS
AROUND -12C AND CONVERGENT NORTHERLY FLOW. 00Z SOUNDINGS FROM INL
AND YPL MAY SUGGEST WHY LES IS STRUGGLING WITH LOW INVERSION HEIGHTS
UNDER 4000 FT AND VERY DRY AIR ALOFT. MQT VWP SUGGESTS THAT THE
INVERSION IS HIGHER DOWNWIND OF LAKE SUPERIOR...BUT THE DRY AIR
ALOFT REMAINS A PROBLEM AS DOES THE SHEAR AT THE TOP OF THE
INVERSION. WITH THAT BEING SAID...THE RUC AND RAPID REFRESH SEEM TO
HAVE A GOOD HANDLE ON THE LES INITIATION ON THE LAND BREEZE
BOUNDARIES...AND EVEN THE 06Z NAM SUGGESTS SOME BETTER BANDS NEAR
IWD ASSOCIATED WITH THE LAND BREEZE. WILL REALLY NEED TO MONITOR THE
BAND JUST NORTH OF IWD THIS MORNING. AS THE LAND BREEZE BREAKS DOWN
THIS MORNING...THE BAND WILL LIKELY MOVE INLAND AS THE PRIMARY
SYNOPTIC FLOW REMAINS NORTHERLY THROUGH THE DAY. WITH THE COLDER
850MB TEMPS OVER THE WESTERN U.P. THIS MORNING...THE SNOW GROWTH
REGION WILL BE IN CONVECTIVE BOUNDARY LAYER WHICH SHOULD HELP SNOW
RATIOS RISE TO 20-25:1 TODAY. THIS WOULD SUGGEST THAT IT WOULD NOT
TAKE MUCH FOR ADVISORY LEVEL SNOW TO BE REACHED TODAY AROUND IWD
TODAY...ESPECIALLY SINCE DEEPER MOISTURE ARRIVES THIS AFTERNOON AS
THE WAVE CURRENTLY OVER MN MOVES ACROSS LAKE SUPERIOR. THIS SHOULD
HELP TO INCREASE LES COVERAGE AND INTENSITY ACROSS THE WEST LATER
THIS AFTERNOON AND ACROSS THE CENTRAL AND EASTERN FORECAST SNOWBELTS
TONIGHT. LAKE INDUCED INSTABILITY WILL ALSO BE HIGHER OVERNIGHT WITH
850MB TEMPS DROPPING TO -16C. HOWEVER...THE PBL FLOW WILL ALSO
BECOME INCREASINGLY ANTICYCLONIC AS THE NIGHT GOES ON AS THE SFC
RIDGE AXIS SHIFTS OVER THE AREA. THIS WILL ALLOW THE WINDS TO BACK
OVERNIGHT WHICH WILL SHIFT THE BEST SNOWFALL BY MORNING TO THE
ONTONAGON TO THE KEWEENAW AS WELL AS ALGER COUNTY. DESPITE THE
FAVORABLE INSTABILITY AND MOISTURE...THE SHEAR IN PBL COMBINED WITH
THE SHIFTING NATURE OF THE BANDS SHOULD LIMIT SNOWFALL TO 1-3
INCHES...MAINLY FROM IWD-CMX AND FROM MQT-P53.
ANY LES ACROSS THE KEWEENAW AND EAST OF MARQUETTE SHOULD RAPIDLY
SHIFT OFFSHORE ON TUESDAY AS THE RIDGE AXIS MOVES SOUTHEAST. WILL
END UP BEING A DECENT AFTERNOON ON TUESDAY WITH SOME SUNSHINE NOT
OUT OF THE QUESTION. CLEAR SKIES SHOULD ALLOW TEMPS TO DROP INTO THE
SINGLE DIGITS BY WED MORNING ACROSS MANY INTERIOR LOCATIONS. THE
NEXT FRONT WILL PASS THROUGH THE AREA WEDNESDAY. THIS FRONT WILL
USHER IN THE COLDEST AIR OF THE SEASON SO FAR. IT STILL LOOKS LIKE A
RATHER SNOWY PERIOD FOR AREAS FAVORED IN W-NW FLOW SUCH AS THE
KEWEENAW PENINUSLA AND AREAS EAST OF MUNISING. IN ADDITION TO THE
PURE LAKE EFFECT...THERE WILL BE SEVERAL OPPORTUNITIES FOR LAKE
ENHANCEMENT AS UPPER DISTURBANCES ROTATE AROUND THE HUDSON BAY LOW.
ALTHOUGH IT IS TOO EARLY FOR ANY WATCHES...PEOPLE IN THE KEWEENAW
AND AREAS EAST OF MUNISING SHOULD SEE SIGNIFICANT SNOW ACCUMULATIONS
FROM WED NIGHT THROUGH FRIDAY (AND PERHAPS EVEN INTO SATURDAY). THE
GFS SOUNDINGS SHOW INVERSION HEIGHTS AROUND 8000 FT WITH LAKE
INDUCED CAPE VALUES AT LEAST 800 J/KG BY THU. ONLY CONCERN FOR A
MAJOR LAKE EFFECT SNOW EVENT IS THE DRY BOUNDARY LAYER WHICH WILL
UNDOUBTEDLY ACCOMPANY THE ARCTIC AIRMASS. FOR NOW...WILL CONTINUE TO
MENTION THE POSSIBILITY FOR HEAVY LES IN THE HAZARDOUS WEATHER
OUTLOOK.
OTHERWISE...THE WEATHER FOR AREAS AWAY FROM LES SHOULD BE FAIRLY
QUIET THROUGH MUCH OF THE WEEK. IT WILL BE MUCH COLDER THAN NORMAL
FOR THU-SAT WITH TEMPS STRUGGLING TO RISE INTO THE 20S. BY
SUNDAY...HEIGHT RISES WILL ALLOW FOR THE LES TO END AND TEMPS TO
RISE BACK TO NEAR NORMAL AS THE FLOW TURNS SWLY.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/
FOR THIS FCST PERIOD...WEATHER AT KIWD/KCMX/KSAW WILL BE DOMINATED
BY LAKE EFFECT CLOUDS/SNOW SHOWERS. MVFR CIGS WILL DOMINATE. AS IS
TYPICAL FOR LAKE EFFECT SNOW SHOWERS...VIS WILL BE QUITE
VARIABLE...RANGING FROM VFR VIS WITH NO PCPN TO MVFR. LOWER VIS
SHOULD BE MORE COMMON LATER TONIGHT INTO MON MORNING AS OVERWATER
INSTABILITY INCREASES...RESULTING IN POTENTIAL OF INCREASED -SHSN
INTENSITY AND THIS STAYS THAT WAY THROUGH THE PERIOD.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WINDS MOSTLY IN THE 10-20 KT RANGE THROUGH TUE AS A HIGH PRES
RIDGE OVER NORTHERN ONTARIO AND THE NRN PLAINS SLOWLY BUILDS ACROSS
LAKE SUPERIOR. AS THE RIDGE SLIPS SE OF THE LAKE AND A COLD
FRONT APPROACHES...SW WINDS WILL LIKELY INCREASE TO GALE FORCE TUE
NIGHT INTO EARLY WED...MAINLY OVER WESTERN AND NCNTRL LAKE SUPERIOR.
A WINTRY PATTERN OF W-NW WINDS WILL THEN PERSIST THRU LATE WEEK WITH
LAKE EFFECT SNOW SHOWERS. GIVEN ARCTIC AIR PASSING OVER THE
LAKE...EFFICIENT MIXING MAY RESULT IN BRIEF GALES AT TIMES LATE IN
THE WEEK. MAY NEED TO CONSIDER THE POTENTIAL OF FREEZING SPRAY AS
WELL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING FOR
LSZ266.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ162.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
DISCUSSION...MRD
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
905 PM MST SUN DEC 4 2011
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY...
EVENING UPDATE...
NO CHANGES ARE PLANNED FOR THE FORECAST. CURRENTLY LOW LEVEL CLOUD
COVER IS THE DOMINATE FEATURE IN DETERMINING OVERNIGHT LOWS.
WHETHER AND AREA CLEARS OUT OR NOT WILL HAVE A 5 TO 10 DEGREE
DIFFERENCE IN OVERNIGHT LOWS. HAVE PLANNED ON MOST OF THE AREA
CLEARING SLOWLY AS LOW LEVEL CLOUD COVER DISSIPATES BEFORE SUNRISE
LIKE THE HRRR MODEL INDICATES. GAH
LATE AFTERNOON UPDATE...
WINDS HAVE DIMINISHED AND VISIBILITIES HAVE IMPROVED IN OUR SE
COUNTIES. THEREFORE ALLOWED THE WSW TO EXPIRE ON TIME AT 00Z.
OCCASIONAL LIGHT SNOW IS STILL POSSIBLE BUT NO ADDITIONAL
ACCUMULATION IS EXPECTED. SCT
AFTERNOON DISCUSSION...
BASED ON WEATHER CAMS...AIRPORT OBSERVATIONS AND LOW VISIBILITIES
FROM SNOW AND BLOWING SNOW...KEPT THE WSW GOING FOR THE SOUTHEAST
ZONES. THE WSW WILL BE REVISITED NEAR 00Z WHEN IT IS SCHEDULED TO
END.
THE SHORT TERM PERIOD WILL INTRODUCE A QUIET PERIOD THROUGH
TUESDAY. TONIGHT A SURFACE HIGH SLIDES SOUTH OVER NORTHEAST
MONTANA AS THE UPPER LEVEL TROUGH MOVES TO OUR EAST. THE SURFACE
HIGH WILL DIMINISH WINDS THIS EVENING TO LIGHT AND VARIABLE AFTER
MIDNIGHT. GOES VISUAL IMAGERY REVEALS CLEARING UPSTREAM IN
SASKATCHEWAN. THEREFORE...SUPPORTED BY MODEL DATA...EXPECT
CLEARING FROM THE NORTH. WITH 1000MB-500MB THICKNESS HEIGHTS
BOTTOMING OUT AT AROUND 505DM AND CLEARING SKIES...THE LOWS
TONIGHT WILL DROP TO BELOW ZERO IN MOST AREAS. COLD AIR DRAINAGE
IS EXPECTED TO ENHANCE TERRAIN DIFFERENCES DUE TO LIGHT SYNOPTIC
WINDS. WITH LIGHT WINDS THE WIND CHILLS SHOULD NOT BE AN ISSUE.
MONDAY/TUESDAY...AN EAST LEANING UPPER LEVEL CHINOOK RIDGE PUSHES
INTO THE PACNW SENDING A WARM FRONT EAST ACROSS MONTANA. PLUS THE
SURFACE HIGH MOVES SOUTH OF NEMONT...SHIFTING SURFACE WINDS TO THE
SOUTHWEST. THIS WILL START A WARMING TREND WITH TEMPERATURES
APPROACHING NORMAL BY TUESDAY. HOWEVER...NEW SNOW COVER MAY
DAMPER A RAPID RETURN AND SLOW SNOW MELT ON MONDAY. YET...BY
TUESDAY A PRE-FRONTAL WARMING SPIKE IN ADDITION TO CONSTANT EROSION
OF THE SNOW COVER BY THE CHINOOK FROM THE NIGHT BEFORE MAY BE
ABLE TO EXPOSE SOME BARE GROUND BEFORE THE NEXT FRONTS ARRIVAL
LATER IN THE WEEK. SCT
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
THE ONLY CHANGES MADE FOR THE AFTERNOON FORECAST ISSUANCE WAS TO
EXPAND PRECIPITATION COVERAGE FOR WEDNESDAY AS THE FORECAST MODELS
NOW SUPPORT PRECIPITATION FURTHER TO THE NORTH AND EAST THEN
PREVIOUSLY FORECAST. ALSO PUT IN SOME SLIGHT CHANCE POPS ACROSS
THE NORTH FOR SUNDAY AS THE MODELS ARE HINTING AT ANOTHER WAVE
DROPPING SOUTHWARD OUT OF CANADA. OTHERWISE THE REMAINDER OF THE
FORECAST AS DISCUSSED BELOW IS ON TRACK. GILCHRIST
PREVIOUS LONG TERM DISCUSSION...ANOTHER PUSH OF COLD AIR EXPECTED
MIDWEEK AS UPPER LOW SLIDES FROM NORTHERN ALASKA TOWARD HUDSON
BAY...WITH THE POLAR JET DIVING INTO CENTRAL CANADA. COLD FRONT
DROPS INTO MONTANA TUESDAY NIGHT WITH STRONG THERMAL DYNAMICS BUT
MOISTURE LIMITED MINIMIZING CHANCES OF SNOW. AS COLD AIR CONTINUES
TO SLIDE INTO MONTANA THE AVAILABLE MOISTURE IMPROVES AS IT POOLS
AGAINST THE MOUNTAINS OF WESTERN AND SOUTHERN MONTANA. UPSLOPE
WILL ADD LIFT FOR SNOW DEVELOPING ACROSS CENTRAL MONTANA WEDNESDAY
NIGHT INTO THURSDAY. TEMPERATURES BECOME QUITE FRIGID BY THURSDAY
AS THE ARCTIC BUILDS SOUTHWARD.
TEMPERATURES BEGIN TO MODERATE INTO THE END OF THE WEEK AS RIDGE
PUSHES ACROSS THE NORTHERN ROCKIES. MODELS DIFFERING ON THE EXTENT
OF RIDGING AND HOW QUICKLY ARCTIC MOVES OUT BUT DID TREND TEMPERATURES
WARMER FOR FRIDAY AND SATURDAY. ANOTHER ARCTIC FRONT DROPS INTO
NORTHERN MONTANA SATURDAY NIGHT AND WENT WITH POPS SLIGHTLY ABOVE
CLIMO. EBERT
&&
.AVIATION...
LOW CLOUDS ARE BEGINNING TO LIFT AS COOL HIGH PRESSURE BUILDS IN
BEHIND THE NOW EXITING LOW PRESSURE SYSTEM. SCATTERED TO BROKEN
LOW CLOUDS WILL LINGER THIS EVENING WITH CEILINGS NEAR THE 3000 FT
VFR/MVFR THRESHOLD. EXPECT SOME AT LEAST PARTIAL CLEARING
OVERNIGHT...WHICH WILL ALLOW TEMPERATURES TO QUICKLY FALL AND
FROST TO FORM. NORTHWEST WINDS AROUND 10 KNOTS THIS EVENING WILL
BECOME LIGHT AND VARIABLE OVERNIGHT AND SOUTHWEST 5 TO 10 KNOTS
DURING THE DAY ON MONDAY.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS RALEIGH NC
121 AM EST MON DEC 5 2011
.SYNOPSIS...
CLOUD COVER AND CHANCES FOR RAIN WILL INCREASE OVER THE CAROLINAS
THROUGH MID WEEK IN ADVANCE OF A COLD FRONT APPROACHING FROM THE
WEST. THE COLD FRONT WILL PUSH OFFSHORE BY THURSDAY...WITH COOLER
AND DRIER CONDITIONS BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 1000 PM SUNDAY...
THE PROBLEM OF THE NIGHT CONTINUES TO BE THE POTENTIAL FOR DENSE FOG
AND LOW STRATUS DEVELOPMENT.
1030+ MB SURFACE HIGH PRESSURE WAS LOCATED OFFSHORE OF THE
MID-ATLANTIC COAST WITH THE RIDGE AXIS EXTENDING SW DIRECTLY OVER
OUR REGION THIS EVENING. THE SURFACE WINDS WERE VERY LIGHT AND
MAINLY FROM THE NNE OVER OUR SE... WITH CALM CONDITIONS UNDER RIDGE
AXIS OVER OUR NW ZONES. THE LATEST SATELLITE DATA INDICATED
SCATTERED AREAS OF STRATOCUMULUS WITH BASES WELL UP AT 6500 FEET OR
SO. THE WV SATELLITE DATA INDICTED HIGH MOISTURE INCREASING ALOFT IN
THE BROAD SW FLOW WITH MOST OF THE PLUME OF MOISTURE AIMING WEST OF
THE APPALACHIANS.
THE LATEST HRRR INDICATES AN EXPLOSION OF FOG/LOW CLOUD DEVELOPMENT
OVER THE NORTHERN COASTAL PLAIN SHORTLY... THEN EXPANDING/DEVELOPING
WESTWARD INTO THE NORTHERN AND EASTERN PIEDMONT BETWEEN 08Z-12Z.
SURFACE OBSERVATIONS WERE ALREADY INDICATING THIS PROCESS WAS
BEGINNING OVER SE VA AND NE NC. THE VERTICAL MOISTURE/WIND PROFILES
OVER THE NORTHEAST AND NORTH CENTRAL NC ZONES ARE MOST FAVORABLE FOR
THE DENSE FOG AND LOW STRATUS. WE WILL GO WITH THE LATEST HRRR
FORECAST WHICH HAS STRONG SUPPORT FROM THE LATEST NAM... AND CURRENT
ANALYZED DATA. NO OTHER CHANGES ARE NEEDED AT THIS TIME. -BADGETT
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 242 PM SUNDAY...
MONDAY:
SLOW MOVING FRONTAL ZONE ASSOCIATED WITH THE FULL LATITUDE TROUGH
ALOFT TO THE WEST OF THE AREA WILL REMAIN WEST OF THE MOUNTAINS ON
MONDAY. AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO
INCREASE A GOOD 15 METERS OR SO FROM TODAY. HOWEVER... INCREASE IN
AFOREMENTIONED MOISTURE AND CLOUD COVER WILL HELP OFFSET THE
INCREASE IN LOW LEVEL THICKNESS VALUES... AS SKIES WILL ONLY IMPROVE
INTO THE PARTLY SUNNY TO MOSTLY CLOUDY RANGE (MORE IMPROVEMENT
SOUTHEAST/EAST VS NORTHWEST). THUS... EXPECT TEMPS WILL BE SIMILAR
TO TODAYS VALUES... MAYBE A BIT WARMER ACROSS THE SOUTHEAST. THIS
YIELDS HIGH TEMPS RANGING FROM AROUND 60 IN THE NORTHWEST TO NEAR 70
IN THE SOUTHEAST. IN ADDITION... CANNOT RULE OUT A FEW WAA SHOWERS
OR SPRINKLES MAINLY ACROSS THE WEST/NORTHWEST (UPSLOPE FLOW).
HOWEVER... WITH A LOT OF DRY AIR ALOFT AND AMOUNT OF MOISTURE AND
LIFT QUITE SHALLOW WILL GO WITH A DRY FORECAST.
MONDAY NIGHT THROUGH TUESDAY NIGHT...SURFACE RIDGE OVER THE FORECAST
AREA GRADUALLY WEAKENS AND SHIFTS EWD MONDAY NIGHT THROUGH TUESDAY.
THIS WILL ALLOW A SURFACE COLD FRONT ASSOCIATED WITH POSITIVELY TILT
UPPER TROUGH (EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN
ROCKIES) TO EDGE EAST...POSSIBLY ENTERING THE NC MOUNTAINS TUESDAY
MORNING. RETURN FLOW ON THE BACKSIDE OF THE HIGH WILL ADVECT LOW
LEVEL MOISTURE INTO CENTRAL NC. RH CROSS SECTIONS SUGGEST MOISTURE
MAINLY CONFINED TO THE LOWEST 5000FT WITH A DECENT LAYER OF DRY AIR
IN THE MID LAYERS OF THE ATMOSPHERE. BEST ISENTROPIC LIFT IN THE
295-300K LAYER OCCURRING NEAR OUR WESTERN PERIPHERY. WHILE COULD SEE
A FEW SPRINKLES ALONG AND EAST OF HIGHWAY 1...BETTER POTENTIAL FOR
MEASURABLE LIGHT PRECIP WILL BE OVER OUR WESTERN COUNTIES...MAINLY
AFTER MIDNIGHT (LIKELY CLOSER TO DAYBREAK). HAVE ADJUSTED POPS
MONDAY NIGHT...KEEPING THE EVENING HOURS DRY THEN LIMITING SLIGHT
CHANCE POPS TO THE WESTERN THIRD OF THE REGION.
BEST CHANCE FOR LIGHT PRECIP AMOUNTS TUESDAY-TUESDAY NIGHT WILL
REMAIN IN VICINITY OF THE SURFACE BOUNDARY THAT WILL INCH E-SE
TOWARD THE NW COUNTIES DURING THIS PERIOD AS DEEP SW FLOW AND
STUBBORN HIGH OFFSHORE WILL RESULT IN LITTLE PUSH TO THIS FEATURE.
THUS...POPS ACROSS CENTRAL NC WILL GRADUATE FROM SOLID CHANCE FAR
N-NW TO SMALL CHANCE SE. MAY SEE A PERIOD WHERE PRECIP ACROSS THE N
AND NW LIMITED/NON-EXISTENT BUT DIFFICULT TO DETERMINE THIS FAR OUT
WHEN THIS WILL OCCUR. PRECIP AMOUNTS TUESDAY INTO TUESDAY NIGHT
SHOULD REMAIN LIGHT (LESS THAN A QUARTER OF INCH MOST LOCALES WITH
JUST A FEW HUNDREDTHS PROBABLE IN THE SE) AS LIFT FOR PRECIP
GENERATION RELATIVELY WEAK.
TEMPS MONDAY NIGHT THROUGH TUESDAY NIGHT SHOULD REMAIN MILD FOR THIS
TIME OF YEAR... AND MAINLY DEPENDENT ON THE AMOUNT OF PRECIP
COVERAGE OVER THE NW. MIN TEMPS LOW-MID 50S. HIGH TEMPS TUESDAY MID
60S NW TO AROUND 70/LOWER 70S SE.
WEDNESDAY AND WEDNESDAY NIGHT...
FORECAST CONFIDENCE LOWER THAN NORMAL BEGINNING THIS PERIOD AS
MEDIUM RANGE GUIDANCE DIFFER QUITE A BIT WITH EASTWARD TRANSLATION
OF ENERGY IN THE SOUTHERN STREAM. THE ECMWF-GFS DIFFERENCE LAST
NIGHT WAS ABOUT 12HRS FROM EACH OTHER (GFS SLOWER). LATEST 12Z MODEL
RUNS SUGGEST A DIFFERENCE OF ABOUT 6-8 HOURS WITH THE GFS SPEEDING
THINGS UP A BIT FROM ITS 06Z RUN. 12Z ECMWF DISPLAY A BIT MORE
CONSISTENCY BUT STILL SOME QUESTIONS ON ITS HANDLING OF THE S/W AND
POTENTIAL SURFACE CYCLOGENESIS JUST S-SE OF OUR REGION.
MODELS DO AGREE THAT S/W IN THE SOUTHERN STREAM WILL START OUT
FAIRLY POTENT THEN WEAKEN AS IT ENCOUNTERS INCREASING CONFLUENCE
ALOFT AS IT TRANSLATE EWD ACROSS THE DEEP SOUTH AND SE U.S LATE
WED-THU. GFS AND ECMWF SUGGEST CYCLOGENESIS OCCURRING LATE WED NIGHT
INTO THU THOUGH GFS FARTHER INLAND (OVER THE FOOTHILLS OF NC) WHILE
ECMWF FAVORS A SOLUTION CLOSER TO THE COAST. THIS WILL HAVE
IMPLICATION ON TEMPS WED AND MORE SO WED NIGHT AS WELL AS CHARACTER
OF PRECIP AS ECMWF FAVORS WIDESPREAD RAIN IN AN OVERRUNNING EVENT
WHILE GFS WOULD SUGGEST PRECIP MORE CONVECTIVE IN NATURE (HIGH
SHEAR/LOW INSTABILITY SCENARIO). STILL...APPEARS HIGHEST THREAT FOR
PRECIP ACROSS CENTRAL NC WILL OCCUR LATE WED INTO THU MORNING...WITH
MOST GUIDANCE FAVORING WED NIGHT.
FOR NOW WILL MAINTAIN PREVIOUS FORECAST OF HIGHER POPS NW VERSUS SE
WED BUT FAVOR HIGHEST POPS ACROSS THE REGION WED NIGHT RATHER THAN
WED. THUS WILL INCREASE POPS TO LIKELY ACROSS THE REGION WED NIGHT
INTO THU AM IN THE EAST. TEMPS WED-WED NIGHT HIGHLY DEPENDENT ON
EVENTUAL PASSAGE/POSITION OF THE SURFACE BOUNDARY. ECMWF WOULD
FAVOR COOLER MIN TEMPS WED NIGHT THAN CURRENTLY ADVERTISED (BY ABOUT
3-4 DEGREES). HOWEVER IF GFS MORE CORRECT...MIN TEMPS WED NIGHT MAY
BE AS MUCH AS 10 DEGREES WARMER THAN FORECAST....ESPECIALLY SE HALF.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 242 PM SUNDAY...
THIS PERIOD STARTS OUT ACTIVE THAN TRANSITIONS TO A COOL DRY WEATHER
SCENARIO FOR THE WEEKEND.
S/W AND ASSOCIATED SURFACE BOUNDARY EXPECTED TO DEPART OUR REGION
THURSDAY. GFS MAINTAINS DECENT CHANCE FOR PRECIP ACROSS THE EASTERN
HALF THROUGH THU AFTERNOON WHILE ECMWF (FASTER THAN GFS) WOULD END
THE PRECIP IN THE EAST PRIOR TO THU AFTERNOON. WILL ADVERTISE POPS
DECREASING WEST-TO EAST THU THOUGH MAINTAIN SMALL CHANCE POP IN THE
EAST UNTIL SUNSET (WORST CASE SCENARIO). EXPECT DECENT CAA IN THE
WAKE OF THE DEPARTING SYSTEM SO TEMPS THU MAY ONLY RECOVER 7-10
DEGREES FROM MORNING LOWS.
STABLE COOL CANADIAN HIGH WILL BUILD INTO AND SETTLE OVER THE SE
U.S. FRI INTO SUN. NORTHERN BRANCH OF WESTERLIES CURRENTLY EXPECTED
TO BE MORE ACTIVE COMPARED TO THE SOUTHERN STREAM SO BULK OF STORM
ACTIVITY WILL OCCUR WELL TO OUR N-NW. THUS EXPECT MAINLY DRY
CONDITIONS THU NIGHT THROUGH SUNDAY. PRESENCE OF BROAD L/W TROUGH
OVER THE REGION AND SURFACE HIGH OF CANADIAN ORIGIN BUILDING INTO
THE REGION SUPPORTS TEMPS SLIGHTLY BELOW NORMAL.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 120 AM MONDAY...
24-HR TAF PERIOD:
LOWER THAN NORMAL CONFIDENCE THROUGH THE TAF PERIOD. THE LATEST
(00Z) GFS/NAM FCST SOUNDINGS ARE FAILING TO CAPTURE BKN060-OVC060
CEILINGS CURRENTLY PRESENT OVER MOST OR ALL OF CENTRAL NC AS OF 05Z
THIS MORNING. INSTEAD...FCST SOUNDINGS SHOW SATURATION IN THE LOWEST
LEVELS (SURFACE TO 500 FT AGL) BY 06Z ACROSS THE ENTIRE AREA...
SOMETHING THAT OBSERVATIONS DO NOT REFLECT ANYWHERE OVER OR UPSTREAM
OF THE AREA WITH THE EXCEPTION OF FAR SOUTHEAST VA. AS A RESULT...IT
IS DIFFICULT TO BELIEVE FCST SOUNDINGS SHOWING IFR/LIFR CONDITIONS
IN FOG/LOW STRATUS DEVELOPING PRIOR TO SUNRISE. WITH THIS IN MIND...
WILL REVERSE COURSE ON THE PREVIOUS TAF FORECAST AND HAVE OPTED TO
ONLY SHOW A TEMPO GROUP FOR MVFR CEILINGS/VISBYS PRIOR TO 12Z THIS
MORNING. WILL INDICATE MVFR CEILINGS EVERYWHERE FROM SUNRISE-SUNSET
TODAY GIVEN THAT THE BOUNDARY LAYER SHOULD CONTINUE TO MOISTEN VIA A
PERSISTENT AND STRENGTHENING SOUTHEASTERLY RETURN FLOW IN THE LOWER
LEVELS. PATCHY LIGHT RAIN/SPRINKLES (AND LOCALLY LOWER CEILINGS/
VISBYS) WILL BE POSSIBLE EVERYWHERE THIS AFTERNOON INTO TONIGHT...
WITH THE RELATIVE BEST CHANCE AT THE INT/GSO TAF SITES...HOWEVER...
CONFIDENCE IN THE EXACT LOCATION OF SAID ACTIVITY IS LOW ENOUGH TO
PRECLUDE MENTIONING AT THIS TIME. WARM ADVECTION WILL FURTHER
STRENGTHEN TONIGHT...AND ANTICIPATE A BETTER CHANCE FOR IFR AND
PERHAPS LIFR CONDITIONS DEVELOPING BY THE END OF THE TAF PERIOD...IN
THE 06-12Z TIME FRAME TUE MORNING. EXPECT LIGHT/VARIABLE OR CALM
WINDS THIS MORNING BECOMING SSE AT ~5 KT THIS AFTERNOON THROUGH THE
REMAINDER OF THE TAF PERIOD.
LOOKING AHEAD:
A COLD FRONT WILL SLOWLY APPROACH THE CAROLINAS FROM THE WEST ON
TUESDAY...MOVING INTO AND PERHAPS STALLING OVER THE AREA TUE
NIGHT/WED. AN UPPER LEVEL DISTURBANCE APPROACHING THE CAROLINAS FROM
THE WEST WED AND CROSSING THE AREA WED NIGHT WILL ENHANCE PRECIP
CHANCES ALONG THE FRONT BEFORE PUSHING IT OFFSHORE WED NIGHT/THU
MORNING. A PROLONGED PERIOD OF SUB-VFR CONDITIONS OVER ALL OR
PORTIONS OF THE AREA IS LIKELY TUE INTO WED...WITH THE BEST CHANCE
FOR WIDESPREAD RAIN AND IFR/LIFR CONDITIONS WED AFTERNOON THROUGH
WED NIGHT. EXPECT VFR CONDITIONS TO RETURN IN THE WAKE OF THE FRONT
THU/FRI. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BADGETT
SHORT TERM...BSD/WSS
LONG TERM...WSS
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1253 AM EST MON DEC 5 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL GRADUALLY OVERSPREAD THE REGION LATE TONIGHT AND
MONDAY MORNING. FOR THE MIDDAY AND AFTERNOON HOURS ON MONDAY
RAINFALL WILL INCREASE IN COVERAGE AND INTENSITY OVER THE WEST AND
SPREAD ACROSS CENTRAL PENNSYLVANIA MONDAY NIGHT. TEMPERATURES WILL
CONTINUE WELL ABOVE AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD
FRONT BRING TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE
TUESDAY AND WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE
REGION FROM THE SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO
BRING SOME WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FOR THE 1230AM UPDATE...ADDED MENTION OF PATCHY DENSE FOG ACRS
MUCH OF THE LWR SUSQ VLY. IR SATL/SFC OBS/SPOTTER REPORTS CONFIRM
LCL VIS NEAR 0SM IN SPOTS. WILL COVER WITH SPS FOR NOW AND
CONTINUE TO MONITOR FOR POSSIBLE DENSE FOG HEADLINE. ALSO CUT-BACK
ON POP CVRG BASED ON RDR IN THE NW MTNS.
PREVIOUS DISCUSSION...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF...18Z NAM AND 00Z RUC SHOWS SOME LIGHT SHOWERS PUSHING
INTO WARREN AND WRN MCKEAN COUNTY TONIGHT /AND PERHAPS ELK COUNTY
AFTER 07Z/. QPF WILL BE LIGHT AND LESS THAN 0.10 OF AN INCH
THROUGH DAYBREAK MONDAY.
THE SHOWERS WILL BE AT THE EASTERN EDGE OF A NNE/SSW RIBBON OF 1
INCH PWAT AIR. A RATHER SHARP GRADIENT TO LOWER...MEAN 925-850 MB
THETA-E AIR WILL OCCUR NEAR THE ALLEGHENY FRONT THOUGH 12Z MONDAY
WITH POPS AOB 10 PERCENT ACROSS OUR CENTRAL AND ERN ZONES.
RELATIVELY HIGHER SFC DEWPOINTS ACROSS THE SUSQ VALLEY AS SOME
PERIODS OF CLEARING WILL SUPPORT THE FORMATION OF FOG/LOW CLOUDS
ONCE AGAIN LATE TONIGHT. NUMERICAL/MOS GUIDANCE INDICATES UP TO A
SVRL HOUR PERIOD OF VSBYS BELOW 1SM AT KLNS...KMDT AND KTHV TOWARD
DAYBREAK. INCLUDED AREAS OF FOG WITH PATCHY DENSE FOG WITH THIS
LATEST GRID UPDATE - ACROSS THE MIDDLE SUSQ...AND ESP LOWER SUSQ
VALLEY LATE TONIGHT/EARLY MONDAY.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS IN MOST PLACES /WHICH WILL BE 10-15F ABOVE NORMAL...WITH
THE GREATEST DEPARTURES OCCURRING ACROSS THE MOUNTAINS/. THE
TYPICALLY COLDER SPOTS NEAR AND TO THE EAST OF THE SUSQ VALLEY
/LIKE KTHV AND KSEG/ WILL DIP INTO THE LOWER AND MID 30S WITH NEAR
CALM AIR.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICEABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
LIGHT WINDS AND MCLEAR SKIES ARE ALLOWING RADIATIONAL FOG TO FORM
ACROSS EASTERN PA LATE THIS EVENING. 04Z OBS SHOWING LIFR CONDS IN
LOW CLOUDS/FOG OVERSPREADING SOUTHEAST PA. ADDITIONAL COOLING
OVERNIGHT SHOULD ALLOW THE FOG TO BECOME THICKER AND SPREAD WEST
AND NORTHWARD INTO THE SUSQ VALLEY. BULK OF LATEST SHORT RANGE MDL
DATA SUGGESTS IFR VSBYS ARE POSSIBLE LATE TONIGHT AT MDT/IPT.
CURRENTLY IFR TO LIFR VSBYS AT LNS WILL CONTINUE UNTIL 15Z.
FOG OVER THE SUSQ VALLEY SHOULD DISSIPATE BY MIDDAY MONDAY. FOCUS
WILL THEN SHIFT TOWARD APPROACHING COLD FRONT...WHICH WILL SPREAD
SHRA INTO THE NW MTNS DURING THE AFTN. IFR CIGS/VSBYS APPEAR
POSSIBLE AT BFD BY MONDAY EVENING. DETERIORATING CONDS SHOULD
SPREAD ACROSS THE REST OF CENTRAL PA MONDAY NIGHT WITH THE ARRIVAL
OF THE FRONT.
OUTLOOK...
TUE...AM LOW CIGS POSSIBLE.
WED...NO SIG WX EXPECTED.
THU...RAIN/SNOWLOW CIGS POSSIBLE.
FRI...SHSN POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT/STEINBUGL
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1222 AM EST MON DEC 5 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL GRADUALLY OVERSPREAD THE REGION LATE TONIGHT AND
MONDAY MORNING. FOR THE MIDDAY AND AFTERNOON HOURS ON MONDAY
RAINFALL WILL INCREASE IN COVERAGE AND INTENSITY OVER THE WEST AND
SPREAD ACROSS CENTRAL PENNSYLVANIA MONDAY NIGHT. TEMPERATURES WILL
CONTINUE WELL ABOVE AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD
FRONT BRING TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE
TUESDAY AND WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE
REGION FROM THE SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO
BRING SOME WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FOR THE 1230AM UPDATE...ADDED MENTION OF PATCHY DENSE FOG ACRS
MUCH OF THE LWR SUSQ VLY. IR SATL/SFC OBS/SPOTTER REPORTS CONFIRM
LCL VIS NEAR 0SM IN SPOTS. WILL COVER WITH SPS FOR NOW AND
CONTINUE TO MONITOR FOR POSSIBLE DENSE FOG HEADLINE. ALSO CUT-BACK
ON POP CVRG BASED ON RDR IN THE NW MTNS.
PREVIOUS DISCUSSION...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF...18Z NAM AND 00Z RUC SHOWS SOME LIGHT SHOWERS PUSHING
INTO WARREN AND WRN MCKEAN COUNTY TONIGHT /AND PERHAPS ELK COUNTY
AFTER 07Z/. QPF WILL BE LIGHT AND LESS THAN 0.10 OF AN INCH
THROUGH DAYBREAK MONDAY.
THE SHOWERS WILL BE AT THE EASTERN EDGE OF A NNE/SSW RIBBON OF 1
INCH PWAT AIR. A RATHER SHARP GRADIENT TO LOWER...MEAN 925-850 MB
THETA-E AIR WILL OCCUR NEAR THE ALLEGHENY FRONT THOUGH 12Z MONDAY
WITH POPS AOB 10 PERCENT ACROSS OUR CENTRAL AND ERN ZONES.
RELATIVELY HIGHER SFC DEWPOINTS ACROSS THE SUSQ VALLEY AS SOME
PERIODS OF CLEARING WILL SUPPORT THE FORMATION OF FOG/LOW CLOUDS
ONCE AGAIN LATE TONIGHT. NUMERICAL/MOS GUIDANCE INDICATES UP TO A
SVRL HOUR PERIOD OF VSBYS BELOW 1SM AT KLNS...KMDT AND KTHV TOWARD
DAYBREAK. INCLUDED AREAS OF FOG WITH PATCHY DENSE FOG WITH THIS
LATEST GRID UPDATE - ACROSS THE MIDDLE SUSQ...AND ESP LOWER SUSQ
VALLEY LATE TONIGHT/EARLY MONDAY.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS IN MOST PLACES /WHICH WILL BE 10-15F ABOVE NORMAL...WITH
THE GREATEST DEPARTURES OCCURRING ACROSS THE MOUNTAINS/. THE
TYPICALLY COLDER SPOTS NEAR AND TO THE EAST OF THE SUSQ VALLEY
/LIKE KTHV AND KSEG/ WILL DIP INTO THE LOWER AND MID 30S WITH NEAR
CALM AIR.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICEABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
A LIGHT WIND AND MCLEAR SKIES ALLOWING RADIATION FOG TO FORM
ACROSS EASTERN PA LATE THIS EVENING. 04Z OBS SHOWING IFR CONDS IN
LOW CLOUDS/FOG OVERSPREADING SOUTHEAST PA. ADDITIONAL COOLING
OVERNIGHT SHOULD ALLOW THE FOG TO BECOME THICKER AND SPREAD
WESTWARD INTO THE SUSQ VALLEY. BULK OF LATEST SHORT RANGE MDL
DATA SUGGESTS IFR VSBYS ARE POSSIBLE LATE TONIGHT AT MDT/IPT AND
VERY LIKELY AT LNS.
FOG OVER THE SUSQ VALLEY SHOULD DISSIPATE BY MIDDAY MONDAY. FOCUS
WILL THEN SHIFT TOWARD APPROACHING COLD FRONT...WHICH WILL SPREAD
SHRA INTO THE NW MTNS DURING THE AFTN. IFR CIGS/VSBYS APPEAR
POSSIBLE AT BFD BY MON EVENING...AND DETERIORATING CONDS SHOULD
SPREAD ACROSS THE REST OF CENTRAL PA MON NITE WITH ARRIVAL OF
FRONT.
OUTLOOK...
TUE...AM LOW CIGS POSSIBLE.
WED...NO SIG WX EXPECTED.
THU...RAIN/SNOWLOW CIGS POSSIBLE.
FRI...SHSN POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT/STEINBUGL
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1140 PM EST SUN DEC 4 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL GRADUALLY OVERSPREAD THE REGION LATE TONIGHT AND
MONDAY MORNING. FOR THE MIDDAY AND AFTERNOON HOURS ON MONDAY
RAINFALL WILL INCREASE IN COVERAGE AND INTENSITY OVER THE WEST AND
SPREAD ACROSS CENTRAL PENNSYLVANIA MONDAY NIGHT. TEMPERATURES WILL
CONTINUE WELL ABOVE AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD
FRONT BRING TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE
TUESDAY AND WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE
REGION FROM THE SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO
BRING SOME WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF...18Z NAM AND 00Z RUC SHOWS SOME LIGHT SHOWERS PUSHING
INTO WARREN AND WRN MCKEAN COUNTY TONIGHT /AND PERHAPS ELK COUNTY
AFTER 07Z/. QPF WILL BE LIGHT AND LESS THAN 0.10 OF AN INCH
THROUGH DAYBREAK MONDAY.
THE SHOWERS WILL BE AT THE EASTERN EDGE OF A NNE/SSW RIBBON OF 1
INCH PWAT AIR. A RATHER SHARP GRADIENT TO LOWER...MEAN 925-850 MB
THETA-E AIR WILL OCCUR NEAR THE ALLEGHENY FRONT THOUGH 12Z MONDAY
WITH POPS AOB 10 PERCENT ACROSS OUR CENTRAL AND ERN ZONES.
RELATIVELY HIGHER SFC DEWPOINTS ACROSS THE SUSQ VALLEY AS SOME
PERIODS OF CLEARING WILL SUPPORT THE FORMATION OF FOG/LOW CLOUDS
ONCE AGAIN LATE TONIGHT. NUMERICAL/MOS GUIDANCE INDICATES UP TO A
SVRL HOUR PERIOD OF VSBYS BELOW 1SM AT KLNS...KMDT AND KTHV TOWARD
DAYBREAK. INCLUDED AREAS OF FOG WITH PATCHY DENSE FOG WITH THIS
LATEST GRID UPDATE - ACROSS THE MIDDLE SUSQ...AND ESP LOWER SUSQ
VALLEY LATE TONIGHT/EARLY MONDAY.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS IN MOST PLACES /WHICH WILL BE 10-15F ABOVE NORMAL...WITH
THE GREATEST DEPARTURES OCCURRING ACROSS THE MOUNTAINS/. THE
TYPICALLY COLDER SPOTS NEAR AND TO THE EAST OF THE SUSQ VALLEY
/LIKE KTHV AND KSEG/ WILL DIP INTO THE LOWER AND MID 30S WITH NEAR
CALM AIR.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A LIGHT WIND AND MCLEAR SKIES ALLOWING RADIATION FOG TO FORM
ACROSS EASTERN PA LATE THIS EVENING. 04Z OBS SHOWING IFR CONDS IN
LOW CLOUDS/FOG OVERSPREADING SOUTHEAST PA. ADDITIONAL COOLING
OVERNIGHT SHOULD ALLOW THE FOG TO BECOME THICKER AND SPREAD
WESTWARD INTO THE SUSQ VALLEY. BULK OF LATEST SHORT RANGE MDL
DATA SUGGESTS IFR VSBYS ARE POSSIBLE LATE TONIGHT AT MDT/IPT AND
VERY LIKELY AT LNS.
FOG OVER THE SUSQ VALLEY SHOULD DISSIPATE BY MIDDAY MONDAY. FOCUS
WILL THEN SHIFT TOWARD APPROACHING COLD FRONT...WHICH WILL SPREAD
SHRA INTO THE NW MTNS DURING THE AFTN. IFR CIGS/VSBYS APPEAR
POSSIBLE AT BFD BY MON EVENING...AND DETERIORATING CONDS SHOULD
SPREAD ACROSS THE REST OF CENTRAL PA MON NITE WITH ARRIVAL OF
FRONT.
OUTLOOK...
TUE...AM LOW CIGS POSSIBLE.
WED...NO SIG WX EXPECTED.
THU...RAIN/SNOWLOW CIGS POSSIBLE.
FRI...SHSN POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
314 AM CST MON DEC 5 2011
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
314 AM CST MON DEC 5 2011
MAIN FORECAST CONCERNS ARE ON SNOW SHOWERS/FREEZING DRIZZLE TODAY
AND WHEN CLOUDS CLEAR.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE EAST PACIFIC INTO SOUTHWEST CANADA...
TROUGHING FROM JAMES BAY SOUTHWEST INTO THE FOUR CORNERS REGION...
AND RIDGING ALONG THE EAST COAST OF THE U.S.. WITHIN THE UPPER
TROUGHING...THE MAIN FEATURE OF INTEREST IS A SHORTWAVE OVER EASTERN
SOUTH DAKOTA. WITH THIS SHORTWAVE...AREAS OF LIGHT SNOW WERE BEING
OBSERVED...WHICH WERE ALSO ALONG A WEAK NORTHWEST-SOUTHEAST ORIENTED
TROUGH THROUGH THE SIOUX FALLS AREA. FARTHER EAST...ANOTHER WEAK
SURFACE TROUGH WAS ANALYZED FROM NEAR EAU CLAIRE TO SHEBOYGAN WI.
CONVERGENCE ALONG THIS TROUGH COMBINED WITH LOW LEVEL MOISTURE IN
PLACE NOTED BY THE STRATUS DECK IS PRODUCING SCATTERED SNOW SHOWERS
AROUND THE TROUGH. THERE HAVE EVEN BEEN SOME FREEZING DRIZZLE
REPORTS...MOSTLY LAST EVENING THROUGH FAIRLY RECENTLY AT VOLK
FIELD...BECAUSE OF LACK OF ICE ISSUES. THE LACK OF ICE IS NOTED BY
THE 00Z GRB AND MPX SOUNDINGS WHICH WERE ONLY SATURATED TO -11 TO
-13C RESPECTIVELY. THE AFOREMENTIONED STRATUS IS QUITE
WIDESPREAD...ENCOMPASSING ALL OF WI...MUCH OF IOWA...THE EASTERN
DAKOTAS AND ALMOST ALL OF MINNESOTA. AS A RESULT OF THE CLOUD
COVER...TEMPERATURES HAVE STAYED MOSTLY IN THE 20S ALL NIGHT.
TODAY AND TONIGHT...SHORTWAVE OVER EASTERN SOUTH DAKOTA IS PROGGED
TO LIFT NORTHEAST ALONG THE EAST SIDE OF THE UPPER TROUGH...CROSSING
NORTHWEST WI AND THE U.P. THIS EVENING. THE TRACK OF THIS
SHORTWAVE...COMBINED WITH MODEL FORECASTS OF THE ASSOCIATED
SURFACE TROUGH BASICALLY DISSIPATING...SUGGESTS LIGHT SNOW WITH IT
SHOULD STAY AWAY FROM THE FORECAST AREA. MEANWHILE...THE SURFACE
TROUGH CURRENTLY PRODUCING THE LIGHT SNOW OVER CENTRAL WISCONSIN
IS FORECAST BY THE 05.00Z NAM/REGIONAL CANADIAN AND 05.06Z HRRR TO
DROP SOUTHWEST THROUGH THE DAY TODAY...POSSIBLY REACHING KLSE BY
00Z. BY THE TIME IT REACHES KLSE...ALL OF THESE MODELS HAVE IT
WEAKENING. THIS SEEMS REASONABLE DUE TO THE LARGE 1040MB SURFACE
HIGH OVER THE WESTERN DAKOTAS PROGGED TO MOVE INTO WESTERN
MINNESOTA...AND THAT IS IN RESPONSE TO THE UPPER TROUGH
APPROACHING THE AREA. THEREFORE...HAVE ONLY INCLUDED A BAND OF
20-30 PERCENT CHANCES ALONG THE SURFACE TROUGH TODAY. THIS
REFLECTS CURRENT RADAR TRENDS WELL TOO. AS FAR AS PRECIPITATION
TYPE GOES...MODEL SOUNDINGS INDICATE THE SAME SETUP AS NOW WITH
CLOUD TOP TEMPS AT MOST AROUND -11C. SINCE THE MAJORITY OF REPORTS
THUS FAR OVERNIGHT HAVE BEEN -SN...WILL CONTINUE THAT BUT MENTION
A CHANCE FOR FREEZING DRIZZLE SINCE -11C REPRESENTS ABOUT A 60
PERCENT CHANCE THAT ICE ACTUALLY EXISTS IN THE CLOUD PER AIRCRAFT
RESEARCH. CONFIDENCE CERTAINLY IS NOT HIGH ENOUGH TO ISSUE A
FREEZING RAIN ADVISORY...ESPECIALLY GIVEN THE MAJORITY OF SNOW
REPORTS. OTHERWISE...ONLY OTHER CONCERN IS THE STRATUS. NAM/RUC
HAVE BEEN DOING THE BEST THUS FAR IN THE LOW LEVEL RH PROGS
MATCHING UP WITH THE STRATUS. BOTH SUGGEST THE AREA STAYS CLOUDY
TODAY...WHICH MAKES SENSE WITH 925-950MB WINDS NORTHEAST TO NORTH.
TONIGHT...THERE COULD BE SOME BREAK UP...ESPECIALLY ALONG THE
NORTHWEST EDGE OF THE FORECAST AREA LATE TONIGHT AS 925MB WINDS
BACK TO THE NORTHWEST AT 12Z. GIVEN THE COLD NATURE OF THE AIRMASS
IN PLACE...ANY CLEARING COULD CAUSE TEMPERATURES TO TANK INTO THE
SINGLE DIGITS. MEANWHILE...CLOUDY AREAS WOULD STAY WARMER IN THE
TEENS AND 20S. NEEDLESS TO SAY...TRICKY LOW TEMPERATURE FORECAST
FOR TONIGHT. GENERALLY FOLLOWED A BLEND OF GUIDANCE FOR HIGHS
TODAY.
TUESDAY THROUGH WEDNESDAY NIGHT...UPPER LEVEL PATTERN IS FORECAST TO
UNDERGO SOME CHANGE DURING THIS PERIOD...IN RESPONSE TO A POWERFUL
UPPER LEVEL TROUGH DIGGING DOWN THROUGH CENTRAL CANADA. AS THIS
TROUGH DIGS SOUTHWARD IT WILL HELP TO PUSH THE TROUGH APPROACHING
THE AREA TONIGHT THROUGH ON TUESDAY...GIVE A BRIEF PERIOD OF UPPER
RIDGING ON TUESDAY NIGHT...THEN CAUSE THE UPPER FLOW TO TURN ZONAL
FOR THE REST OF THE PERIOD. AS THE UPPER TROUGH MOVES THROUGH THE
AREA ON TUESDAY...WHICH MEANS THE SURFACE RIDGE WILL DO THE SAME...
ANTICIPATING SKIES TO CLEAR NORTHWEST TO SOUTHEAST. ALTHOUGH MORE
SUN IS EXPECTED...THE 850MB TEMPS FALL TO -10 TO -12C...SO HIGHS
WILL ACTUALLY END UP COOLER THAN TODAY. MOSTLY CLEAR AND COOL
CONDITIONS CONTINUE TUESDAY NIGHT THANKS TO SUBSIDENCE UNDER THE
UPPER RIDGING. A 5-10 KT SOUTHWEST WIND WILL HELP KEEP TEMPERATURES
FROM TANKING BELOW ZERO TUESDAY NIGHT...THOUGH THE WIND IS EXPECTED
TO DROP WIND CHILLS INTO THE SINGLE DIGITS BELOW ZERO. A BRIEF WARM
UP IS FORECAST FOR WEDNESDAY WITH 850MB TEMPS CLIMBING UP TO AROUND
-6C AT 18Z. HOWEVER...A COLD FRONT COMING THROUGH THE ZONAL FLOW
LOOKS TO CROSS LATE IN THE DAY...BRINGING AN INCREASE OF MID-HIGH
CLOUDS BEHIND IT. AS WE GO THROUGH WEDNESDAY NIGHT...THE 05.00Z
GFS/CANADIAN/NAM ALL WANT TO PRODUCE SOME LIGHT PRECIPITATION OUT OF
THESE CLOUDS...LIKELY A RESULT OF SOME MID-LEVEL FRONTOGENESIS. NOT
QUITE SOLD ON THIS PRECIPITATION YET...ESPECIALLY WITH THE 05.00Z
ECMWF STILL DRY AND REALLY THE FIRST SIGNAL OF IT. THEREFORE...HAVE
ONLY INCREASED CLOUD COVER AT THIS TIME. THE CLOUDS SHOULD HELP KEEP
TEMPERATURES UP SOME WEDNESDAY NIGHT. FOLLOWED A BLEND OF GUIDANCE
THEN.
.LONG TERM...THURSDAY THROUGH SUNDAY NIGHT
314 AM CST MON DEC 5 2011
05.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES REMAIN IN PRETTY GOOD
AGREEMENT FOR THE LONG TERM FORECAST...BOTH BETWEEN EACH RUN AND
WHAT WAS SEEN YESTERDAY...LEADING TO ABOVE AVERAGE CONFIDENCE. A
SHORTWAVE TROUGH COMING AROUND THE POWERFUL CENTRAL CANADA TROUGH IS
PROGGED TO DROP INTO THE NORTHERN PLAINS THURSDAY...CROSSING THE
AREA THURSDAY NIGHT INTO FRIDAY. THERE REMAINS SOME SIGNALS OF A
MID-LEVEL FRONTOGENESIS BAND AND UPPER JET INDUCED PRECIPITATION AS
THIS SHORTWAVE TROUGH APPROACHES THE AREA. HOWEVER...A CONSENSUS OF
THE MODELS HAS SHOWN A SHIFT SOUTH...SUCH THAT IT CROSSES MOSTLY THE
SOUTHERN HALF OF IOWA AND NORTHERN ILLINOIS DURING THURSDAY NIGHT.
NOTE...THE NEW 05.00Z ECMWF HAS SHIFTED BACK NORTH...BUT NOT ENOUGH
CONFIDENCE EXISTS TO PUT CHANCES FARTHER NORTH YET. AFTER THIS...IT
LOOKS LIKE A SOLID DRY FORECAST HEADING INTO THE WEEKEND AS THE
UPPER FLOW TRANSITIONS TO ZONAL. SHOULD SEE A WARMING TREND TOO AS
DOWNSLOPING MOTION OFF THE ROCKIES OF PACIFIC AIR CAUSES
TEMPERATURES TO MODIFY. SO AFTER A CHILLY FRIDAY AND FRIDAY NIGHT
WITH 850MB TEMPS PROGGED AS COLD AS -20C...THESE WILL WARM UP
DRAMATICALLY...REACHING TO 0 TO +2C BY SUNDAY. LOOKING
BEYOND...RIGHT NOW IT APPEARS ABOVE NORMAL TEMPERATURES COULD
PERSIST INTO THE EARLY PORTION OF NEXT WEEK WITH ZONAL FLOW
CONTINUING.
&&
.AVIATION...
1130 PM CST SUN DEC 4 2011
LOW LEVEL SATURATION REMAINS AMPLE FOR THE REST OF TONIGHT THROUGH
MUCH OF MONDAY...ALTHOUGH LATEST 00Z MODEL RUNS SUGGEST SOME PUSH
OF THIS LOW MOISTURE EAST BY THE EVENING. WHILE CIGS WOULD IMPROVE
TO VFR...SOME MID CLOUDS WILL ALREADY BE RETURNING AHEAD OF AN UPPER
LEVEL SHORTWAVE TROUGH. CONFIDENCE IS SHAKY IN JUST HOW SOON
KRST/KLSE WILL BREAK OUT OF THE MVFR CIGS...AND WILL SHOOT FOR 00Z
RIGHT NOW. ANTICIPATE THAT THAT TIMING WILL NEED TO BE REFINED.
COULD SEE A FEW FLURRIES OUT OF THE CLOUDS OVERNIGHT THROUGH
MONDAY...BUT DO NOT ANTICIPATE ANY ACCUMULATION OR APPRECIABLE /IF
ANY/ REDUCTIONS TO VSBYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 AM CST MON DEC 5 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1142 PM CST SUN DEC 4 2011
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATED...FREEZING DRIZZLE APPEARS TO BE MORE WIDESPREAD OVER
WEST CENTRAL WISCONSIN WITH SOME MID LEVEL DRYING WORKING
SOUTHWARD. MOIST CYCLONIC FLOW OVER EASTERN WISCONSIN WOULD
DIMINISH THREAT. SOME OBSERVATIONS OVER CENTRAL WISCONSIN WERE
REPORTING SOME FLURRIES AND LIGHT MIX SO WILL ADD A SMALL MENTION
TO THE FORECAST IN THE AREA. LESS OF A THREAT OF ZL EAST OF AUW
WITH SURFACE TEMPS STILL ABOVE FREEZING. CALL TO SOME LAW
ENFORCEMENTS DEPARTMENTS IN CENTRAL WISCONSIN REPORTING LIGHT
SNOW. OTHERWISE THIS BAND OF LIGHT SNOW WITH WEAK TROUGH AND
SURFACE REFLECTION WILL CONTINUE TO DROP SOUTH OVER CENTRAL AND
EAST CENTRAL WISCONSIN OVERNIGHT.
TDH
&&
.PREV DISCUSSION...ISSUED AT 535 PM CST SUN DEC 4 2011...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DOUBLE
BARRELED LOW PRESSURE MOVING ACROSS THE ONTARIO-QUEBEC BORDER AND
THE STRAITS OF MACKINAC...AND A COLD FRONT STRETCHING FROM NORTHERN
LOWER MICHIGAN TO THE SOUTHERN MISSISSIPPI VALLEY. WITH NORTHWEST
FLOW IN PLACE AND DELTA T/S INCREASING TO 14C...CLOUD COVER HAS BEEN
STUBBORN TO DISSIPATE THOUGH PRECIP HAS EXITED TO THE NORTHEAST BY
MIDDAY. A SURFACE TROUGH IS TRYING TO DEVELOP OVER NORTHEAST AND CENTRAL
WISCONSIN THIS AFTERNOON AND A FEW SNOW SHOWERS/FLURRIES HAVE
DEVELOPED OVER THE PAST HOUR. SOME CLEARING NOTED OVER NORTHERN
MINNESOTA WHERE DEWPOINTS HAVE FALLEN TO THE LOWER TEENS. WITH
NORTHERLY FLOW IN PLACE OVER THE NEXT 24 HOURS...SMALL PRECIP
CHANCES AND CLOUD TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT... AS HIGH PRESSURE BUILDS OVER THE NORTHERN PLAINS...WEAK
CYCLONIC FLOW WILL LINGER ACROSS THE REGION. LOW LEVEL FLOW WILL
VEER FROM THE NORTHWEST TO THE NORTH...WHICH WILL KEEP MOISTURE
STREAMING OFF LAKE SUPERIOR. AS A RESULT...SCT LAKE EFFECT SNOW
SHOWERS WILL PREVAIL OVER THE SNOW BELT OF N-C WISCONSIN FOR THE
ENTIRE NIGHT. FARTHER SOUTH...A WEAK SURFACE TROUGH WILL MOVE SOUTH
OVER CENTRAL WISCONSIN THIS EVENING. MOISTURE DEPTH WILL EXTEND
BEYOND 800MB AND -10C...SO IT SEEMS PLAUSIBLE THAT FLURRIES OR VERY
LIGHT SNOW SHOWERS ARE POSSIBLE ALONG THE TROUGH. HAVE ADDED
SLIGHTLY MORE TEMPORAL RESOLUTION TO ACCOUNT FOR THIS.
OTHERWISE...DO NOT SEE MUCH OF AN OPPORTUNITY FOR CLEARING...EXCEPT
IN THE DOWN SLOPING REGIONS OF NORTHEAST WISCONSIN WHERE SOME HOLES
MAY DEVELOP...ESPECIALLY LATE TONIGHT. LOWS IN THE UPPER TEENS
NORTH TO UPPER 20S SOUTHEAST.
MONDAY...ONLY SOME SUBTLE CHANGES HEADING INTO MONDAY. SHORTWAVE
ENERGY OVER THE PLAINS WILL LIFT TO THE NORTHEAST OVER NW
WISCONSIN...BUT WITH VERY LITTLE IMPACT ON OUR WEATHER. WILL
CONTINUE TO HAVE NORTHERLY FLOW TOMORROW WITH SOME MINOR COLD
ADVECTION THAT WILL DROP 850MB TEMPS IN THE NEGATIVE LOW TO MID
TEENS. LIGHT LAKE EFFECT SNOW SHOWERS WILL PREVAIL OVER THE SNOW
BELT OF N-C WISCONSIN...WHILE MOSTLY CLOUDY CONDITIONS WILL BE THE
RULE ELSEWHERE. HIGHS IN THE MIDDLE 20S NORTH TO MIDDLE 30S
SOUTHEAST.
LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...THE MAIN FCST
CONCERN IS THE ARRIVAL OF COLDER ARCTIC AIR LATE IN THE NEXT WORK
WEEK.
A STRONG UPPER RIDGE WILL COVER THE EASTERN PACIFIC...SOUTHWEST
CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...WITH A
POSITIVELY-TILTED UPPER TROF MOVG OUT OF THE NORTHERN PLAINS INTO
THE WESTERN GREAT LAKES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON MONDAY NIGHT AND TUESDAY...BUT WITH A SFC RIDGE OF
HIGH PRESSURE IN PLACE...EXPECT MINIMAL IMPACT ON OUR WEATHER.
SHORT-WAVE ENERGY TOPPING THE WESTERN RIDGE AND DIVING INTO THE
NORTHERN PLAINS WILL HELP TO CARVE A BROAD TROF OVER THE CENTRAL
U.S. BY THURSDAY. A SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN
WI ON THURSDAY...WITH H8 TEMPS PLUMMETING TO AROUND -20 C LATE
THURSDAY NIGHT INTO FRIDAY. THIS WILL LEAD TO OUR COLDEST
TEMPERATURES SO FAR THIS SEASON. THE COLD SNAP WILL BE BRIEF...
AS SOUTHWEST WINDS DEVELOP IN THE WAKE OF THE RETREATING ARCTIC
HIGH OVER THE WEEKEND.
A LARGE RIDGE OF HIGH PRESSURE WILL BUILD INTO NW WI ON MONDAY
NIGHT...THEN MOVE THROUGH GRB CWA ON TUESDAY. LINGERING LAKE-EFFECT
SNOW SHOWERS OVER NC WI SHOULD COME TO AN END AS THE RIDGE AXIS
ARRIVES ON TUESDAY.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING ON THURSDAY.
THE ECMWF HAS BACKED OFF ON THE POTENTIAL FOR SNOW ALONG THE
ARCTIC FRONT ON THU NGT/FRI...AND IS FOCUSING FARTHER SE...FROM
SOUTHERN WI INTO LOWER MICHIGAN. WILL NEED TO KEEP AN EYE ON THIS
OVER THE NEXT FEW DAYS TO SEE IF THIS TREND WILL HOLD. CONFIDENCE
IS FAIRLY HIGH FOR THE ARRIVAL OF MUCH COLDER TEMPERATURES LATE IN
THE WORK WEEK...ALTHOUGH THE COLD IS EXPECTED TO BE SHORT-LIVED.
A WARM FRONT IS EXPECTED TO ARRIVE ON SUNDAY...WITH TEMPERATURES
CLIMBING BACK TO ABOVE NORMAL.
DESPITE THE PRESENCE OF A COLD AIR MASS FROM WEDNESDAY THROUGH
SATURDAY...WIND TRAJECTORIES WILL NOT BE FAVORABLE FOR LK-EFFECT
SNOW.
&&
.AVIATION...A WEAK SHORT WAVE WITH SUBTLE SURFACE REFLECTION
CONTINUES TO DROP SOUTH OVER CENTRAL AND EAST CENTRAL WISCONSIN
THIS EVENING. A BAND OF MVFR VSBYS DUE TO SNOW ASSOCIATED WITH
THIS FEATURE WILL CONTINUE TO DROP SOUTH OVERNIGHT...PERHAPS
FINALLY DEPARTING SOUTHERN AREAS AFTER 10Z. OTHERWISE MVFR CIGS
WITH VFR VSBYS TO DOMINATE TO REGION ON MONDAY. A FEW FLURRIES MAY
LINGER IN THE MORNING HOURS.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
456 AM MST MON DEC 5 2011
.DISCUSSION...
347 AM MST MON DEC 5 2011
MAIN FORECAST PROBLEM WILL BE A PROBLEMATIC TEMPERATURE FORECAST
THROUGH THE SHORT TERM. SATELLITE SHOWING AN AMPLIFIED AND
RETROGRESSIVE FLOW FROM THE PACIFIC INTO CENTRAL NORTH AMERICA.
AMPLIFIED UPPER RIDGE SLOWING MOVING WEST AS TROUGH THAT EXTENDS FROM
EASTERN CANADA INTO THE SOUTHWEST PORTION OF THE COUNTRY CONTINUES TO
SAG TO THE SOUTH AND WEST. VERY COLD AIR MASS IN PLACE WITH COLDER
AIR POISED TO COME FURTHER SOUTH.
AT JET LEVEL THE MODELS INITIALIZED FINE. AT MID LEVELS...THE UKMET
INITIALIZED A LITTLE BETTER...ESPECIALLY WITH THE NORTHERN END OF
THE TROUGH. THE MODELS TENDED TO HAVE THE SURFACE RIDGING TOO FAR
SOUTH AND EAST. THE NAM FOLLOWED BY THE ECMWF WAS DOING A LITTLE
BETTER HERE. WITH THE LOW LEVEL THERMAL FIELD...THE GFS WAS DOING
SLIGHTLY BETTER THAN THE OTHER GUIDANCE.
TODAY/TONIGHT...WAS HARD TO TELL THE EXACT EXTENT OF THE SNOW FIELD
DUE TO CLOUD COVER OVER THE AREA. THAT AND CLOUD COVER THROUGH
TONIGHT WILL BE THE MAIN PLAYERS IN WHAT THE TEMPERATURES WILL DO.
DEFINITELY LOOKS LIKE A LOT OF CLOUDS AROUND THROUGH THE DAY. THAT
COMPLICATED BY THE SNOW COVER...WILL MAKE FOR A COLD DAY. BASED ON
LATEST TRENDS AND MODEL DATA...DECIDED TO LOWER MAXES A FEW
DEGREES.
UPPER AIR ANALYSIS SHOWS EXTREMELY COLD AIR UPSTREAM AT MID LEVELS.
LOOKING AT THE 700 TO 500 MB ANALYSIS...IT WOULD APPEAR THAT THERE
SHOULD BE VERY GOOD LAPSE RATES BUT MODELS REALLY DO NOT SHOW
THAT. UPSTREAM SOUNDINGS WOULD INDICATE MOST IF NOT THE ENTIRE
SOUNDING IS -10 C OR COLDER/IN THE DENDRITIC ZONE. MODELS INDICATE
SOME KIND OF LIFT ALBEIT NOT THAT STRONG THROUGH THE DAY...
ESPECIALLY IN THE SOUTH. MOISTURE IS SHALLOW. HOWEVER...AM THINKING
WITH SUCH A COLD AIR MASS IN PLACE...WOULD NOT TAKE MUCH TO PRODUCE
SOME FLURRIES. SO AT THIS TIME...INSERTED FLURRIES INTO THE SOUTHERN
PORTION OF THE AREA THROUGH EARLY EVENING.
HUGE DIFFERENCE TONIGHT IN WHAT THE MODELS THINK THE CLOUDS
AND RESULTING TEMPERATURE FORECAST WILL BE. NAM BELIEVES THERE WILL
BE A LOT OF CLOUDS AROUND WHILE THE OTHER MODELS CLEAR IT OUT. THE
SOUTHERN PORTION OF THE AREA WILL CLEAR OUT THE LAST AND WILL HAVE
THE LEAST COLD MINS. AT THIS TIME BELIEVE THAT THE COLDER/LEAST CLOUD
COVER WILL OCCUR. HOWEVER...ENOUGH UNCERTAINTY FOR ME TO NOT GO FOR
IT. TENDED TO SPLIT THE DIFFERENCE BUT WENT SLIGHTLY TOWARD THE
COLDER GUIDANCE. WINDS WILL BE LESS THAN 10 MPH MOST AREAS.
HOWEVER...IF THE COLDEST...MUCH BELOW ZERO MINS...ARE REALIZED...WIND
CHILL ADVISORY CRITERIA COULD BE REACHED. WILL BRIEF IN THE NEXT
SHIFT AND HIGHLIGHT THIS IN THE HWO.
TUESDAY/TUESDAY NIGHT...LOW WIND CHILLS WILL OCCUR EARLY IN THE
MORNING. DESPITE THE GENERAL TENDENCY OF THE MODELS TO HAVE A
NORTHEAST TO SOUTHWEST JET AXIS THAT BEGINS TO MOVE ACROSS THE AREA
FROM LATE MORNING THROUGH AT LEAST THE EVENING HOURS...THERE IS A
BIG MODEL DIFFERENCE IN HOW TO HANDLE THE JET AND THE RESULTING
UPPER TROUGH THAT IS MOVING EAST AND SOUTH OF THE AREA. FOR THE EASY
PART IT LOOKS LIKE A LOT MORE SUN AT THIS TIME. HOWEVER...WOULD
STILL EXPECT THE SNOW FIELD TO HAVE CHANGED LITTLE DUE TO THE LACK
OF SUNSHINE DURING THE PREVIOUS TWO DAYS AND COOLING SOIL
TEMPERATURES. OF COURSE A MAJOR CONTRIBUTOR TO THIS IS HOW COLD THE
DAY STARTS.
IN ADDITION MORE OF THE DETERMINISTIC MODEL OUTPUT WITH ENSEMBLE
SUPPORT IS WANTING TO CUT OFF A LOW ON THE SOUTHERN END OF THIS
TROUGH NOT TOO FAR AWAY FROM THE AREA...WITH THE LAST TWO RUNS OF THE
NAM...LATEST SREF...AND NOW EVEN MORESO THE 06Z GFS THE MOST
AGGRESSIVE WITH THIS. ALL THINGS CONSIDERED...THE MODELS OVERALL LOOK
TOO WARM WITH THE EXCEPTIONS OF THE CANADIAN AND NAM. TRENDED TOWARD
THE COOLER SIDE OF GUIDANCE BUT THIS COULD CHANGE.
WEDNESDAY/WEDNESDAY NIGHT...MAIN JET AXIS LOOKS TO STAY NORTH AND
EAST OF THE AREA THROUGH THE PERIOD. ABOVE DISCUSSION ON BEHAVIOR
OF THE UPPER TROUGH WILL HAVE A SIGNIFICANT IMPACT ALONG WITH THE
SNOW COVER ON THE HIGH TEMPERATURES. THE COOLER GUIDANCE SUPPORTED
THE CURRENT FORECAST AND DID NOT CHANGE. BUT AGAIN CONFIDENCE IS
LOW.
THANKS TO ALL THAT COLLABORATED.
BULLER
THURSDAY THROUGH SUNDAY...THROUGH THE PERIOD AN UPPER LEVEL TROUGH
WILL REMAIN OVER EASTERN CANADA...WITH THE UPPER LEVEL RIDGE
CURRENTLY OVER THE PACIFIC BUILDING OVER THE CONUS THROUGH SATURDAY.
THURSDAY A COLD FRONT WILL MOVE THROUGH THE HIGH PLAINS. MODELS
DISAGREE WITH THE TIMING OF THE PASSAGE...WITH IT EITHER MOVING
THROUGH DURING THE EARLY MORNING OR OVERNIGHT. BEHIND THE FRONT AN
UPPER LEVEL TROUGH WILL MOVE THROUGH THURSDAY NIGHT. MODELS ARE IN
GOOD AGREEMENT WITH PLACEMENT AND SPEED OF THE TROUGH. BETTER
FORCING LOOKS TO BE NORTH OF THE CWA...SO WILL KEEP THE FORECAST DRY
THURSDAY AS THE FRONT AND TROUGH PASS THROUGH. HOWEVER A FEW
FLURRIES MAY BE POSSIBLE IN THE EAST AS SOME FORCING WILL BE PRESENT
AS THE TROUGH MOVES THROUGH OVERNIGHT. FRIDAY THE UPPER LEVEL RIDGE
BEGINS TO BUILD OVER THE REGION WITH A SPLIT FLOW PATTERN DEVELOPING.
BY SUNDAY THE RIDGE FLATTENS OUT OVER THE CENTRAL PLAINS. MEANWHILE
AN UPPER LEVEL TROUGH MOVES DOWN FROM CANADA ALONG THE WEST COAST.
AS THE TROUGH MOVES SOUTH THE UPPER LEVEL FLOW BEGINS TO MERGE ONCE
AGAIN...WHICH MAY GIVE THE REGION A SHOT AT PRECIPITATION NEXT WEEK.
TEMPERATURES THROUGH THE PERIOD WILL WARM AS THE UPPER LEVEL RIDGE
BUILDS IN. HOWEVER THE WARM UP WILL DEPEND ON HOW MUCH SNOW IS
PRESENT. CURRENT BLEND OF PREVIOUS FORECAST AND LATEST MODELS HAVE
VALUES BELOW MOST GUIDANCE SO WILL LEAVE TEMPS AS THEY ARE. HIGHS
WILL BE AS MUCH AS 10 DEGREES BELOW NORMAL WITH LOWS NEAR TO A FEW
DEGREES BELOW NORMAL.
JTL
&&
.AVIATION...
426 AM MST MON DEC 5 2011
VFR TO MVFR CONDITIONS WILL BE POSSIBLE FOR THE 12Z TAFS. CURRENT
SATELLITE AND OBS SHOW LOW CLOUDS AND PRECIP OVER COLORADO SOUTH
INTO THE TEXAS PANHANDLE. SOUNDINGS SHOW THE LOW CLOUDS MAKING
THEIR WAY TO THE TAF SITES THROUGH EARLY AFTERNOON. SREF SHOWS A GOOD
POSSIBILITY OF IFR CEILINGS DURING THE AFTERNOON FOR KGLD. HOWEVER
MOS AND NAM DO NOT...ALTHOUGH THE HRRR DOES SHOW A SMALL AREA OF
IFR CEILINGS NEAR GLD FOR A COUPLE HOURS DURING THE AFTERNOON. AM
NOT CONFIDENT ENOUGH TO PLACE IFR CEILINGS IN...BUT WILL ADJUST
THE MVFR CEILINGS TO BEGIN SOONER FOLLOWING GUIDANCE. FOR KMCK LOW
CEILINGS LOOK TO REMAIN JUST EAST AND SOUTH OF THE SITE UNTIL LATE
MORNING BEFORE DROPPING DURING THE AFTERNOON. CEILINGS FOR THE TAF
SITES LOOK TO REMAIN MVFR THROUGH MOST OF THE NIGHT BEFORE LIFTING
TUESDAY MORNING. FOR KGLD THERE COULD BE SOME VIS REDUCTIONS
OVERNIGHT AS TEMPERATURES PLUMMET. WILL ONLY CARRY A SLIGHT
REDUCTION FOR NOW.
JTL
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
733 AM EST MON DEC 5 2011
.DISCUSSION...
RECENT RADAR IMAGES ARE STARTING TO SHOW SOME ORGANIZATION TO THE
LES...ESPECIALLY JUST OFFSHORE OF MARQUETTE COUNTY AS WELL AS A
CONVERGENCE BAND JUST OFFSHORE NEAR SAXON HARBOR. WITH GENERAL LIGHT
WINDS ACROSS THE INLAND AREAS...STRONG LAND BREEZES HAVE DEVELOPED
THAT HAS HELPED THESE BANDS TO FORM. THE MAIN PROBLEM IS THAT LES
POTENTIAL IS STILL VERY UNCLEAR TODAY. IN A GENERAL SENSE...THE LES
IS HAVING A HARD TIME DEVELOPING THIS MORNING DESPITE 850MB TEMPS
AROUND -12C AND CONVERGENT NORTHERLY FLOW. 00Z SOUNDINGS FROM INL
AND YPL MAY SUGGEST WHY LES IS STRUGGLING WITH LOW INVERSION HEIGHTS
UNDER 4000 FT AND VERY DRY AIR ALOFT. MQT VWP SUGGESTS THAT THE
INVERSION IS HIGHER DOWNWIND OF LAKE SUPERIOR...BUT THE DRY AIR
ALOFT REMAINS A PROBLEM AS DOES THE SHEAR AT THE TOP OF THE
INVERSION. WITH THAT BEING SAID...THE RUC AND RAPID REFRESH SEEM TO
HAVE A GOOD HANDLE ON THE LES INITIATION ON THE LAND BREEZE
BOUNDARIES...AND EVEN THE 06Z NAM SUGGESTS SOME BETTER BANDS NEAR
IWD ASSOCIATED WITH THE LAND BREEZE. WILL REALLY NEED TO MONITOR THE
BAND JUST NORTH OF IWD THIS MORNING. AS THE LAND BREEZE BREAKS DOWN
THIS MORNING...THE BAND WILL LIKELY MOVE INLAND AS THE PRIMARY
SYNOPTIC FLOW REMAINS NORTHERLY THROUGH THE DAY. WITH THE COLDER
850MB TEMPS OVER THE WESTERN U.P. THIS MORNING...THE SNOW GROWTH
REGION WILL BE IN CONVECTIVE BOUNDARY LAYER WHICH SHOULD HELP SNOW
RATIOS RISE TO 20-25:1 TODAY. THIS WOULD SUGGEST THAT IT WOULD NOT
TAKE MUCH FOR ADVISORY LEVEL SNOW TO BE REACHED TODAY AROUND IWD
TODAY...ESPECIALLY SINCE DEEPER MOISTURE ARRIVES THIS AFTERNOON AS
THE WAVE CURRENTLY OVER MN MOVES ACROSS LAKE SUPERIOR. THIS SHOULD
HELP TO INCREASE LES COVERAGE AND INTENSITY ACROSS THE WEST LATER
THIS AFTERNOON AND ACROSS THE CENTRAL AND EASTERN FORECAST SNOWBELTS
TONIGHT. LAKE INDUCED INSTABILITY WILL ALSO BE HIGHER OVERNIGHT WITH
850MB TEMPS DROPPING TO -16C. HOWEVER...THE PBL FLOW WILL ALSO
BECOME INCREASINGLY ANTICYCLONIC AS THE NIGHT GOES ON AS THE SFC
RIDGE AXIS SHIFTS OVER THE AREA. THIS WILL ALLOW THE WINDS TO BACK
OVERNIGHT WHICH WILL SHIFT THE BEST SNOWFALL BY MORNING TO THE
ONTONAGON TO THE KEWEENAW AS WELL AS ALGER COUNTY. DESPITE THE
FAVORABLE INSTABILITY AND MOISTURE...THE SHEAR IN PBL COMBINED WITH
THE SHIFTING NATURE OF THE BANDS SHOULD LIMIT SNOWFALL TO 1-3
INCHES...MAINLY FROM IWD-CMX AND FROM MQT-P53.
ANY LES ACROSS THE KEWEENAW AND EAST OF MARQUETTE SHOULD RAPIDLY
SHIFT OFFSHORE ON TUESDAY AS THE RIDGE AXIS MOVES SOUTHEAST. WILL
END UP BEING A DECENT AFTERNOON ON TUESDAY WITH SOME SUNSHINE NOT
OUT OF THE QUESTION. CLEAR SKIES SHOULD ALLOW TEMPS TO DROP INTO THE
SINGLE DIGITS BY WED MORNING ACROSS MANY INTERIOR LOCATIONS. THE
NEXT FRONT WILL PASS THROUGH THE AREA WEDNESDAY. THIS FRONT WILL
USHER IN THE COLDEST AIR OF THE SEASON SO FAR. IT STILL LOOKS LIKE A
RATHER SNOWY PERIOD FOR AREAS FAVORED IN W-NW FLOW SUCH AS THE
KEWEENAW PENINUSLA AND AREAS EAST OF MUNISING. IN ADDITION TO THE
PURE LAKE EFFECT...THERE WILL BE SEVERAL OPPORTUNITIES FOR LAKE
ENHANCEMENT AS UPPER DISTURBANCES ROTATE AROUND THE HUDSON BAY LOW.
ALTHOUGH IT IS TOO EARLY FOR ANY WATCHES...PEOPLE IN THE KEWEENAW
AND AREAS EAST OF MUNISING SHOULD SEE SIGNIFICANT SNOW ACCUMULATIONS
FROM WED NIGHT THROUGH FRIDAY (AND PERHAPS EVEN INTO SATURDAY). THE
GFS SOUNDINGS SHOW INVERSION HEIGHTS AROUND 8000 FT WITH LAKE
INDUCED CAPE VALUES AT LEAST 800 J/KG BY THU. ONLY CONCERN FOR A
MAJOR LAKE EFFECT SNOW EVENT IS THE DRY BOUNDARY LAYER WHICH WILL
UNDOUBTEDLY ACCOMPANY THE ARCTIC AIRMASS. FOR NOW...WILL CONTINUE TO
MENTION THE POSSIBILITY FOR HEAVY LES IN THE HAZARDOUS WEATHER
OUTLOOK.
OTHERWISE...THE WEATHER FOR AREAS AWAY FROM LES SHOULD BE FAIRLY
QUIET THROUGH MUCH OF THE WEEK. IT WILL BE MUCH COLDER THAN NORMAL
FOR THU-SAT WITH TEMPS STRUGGLING TO RISE INTO THE 20S. BY
SUNDAY...HEIGHT RISES WILL ALLOW FOR THE LES TO END AND TEMPS TO
RISE BACK TO NEAR NORMAL AS THE FLOW TURNS SWLY.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/
FOR THIS FCST PERIOD...WEATHER AT KIWD/KCMX/KSAW WILL BE DOMINATED
BY LAKE EFFECT CLOUDS/SNOW SHOWERS. MVFR CIGS WILL DOMINATE. AS IS
TYPICAL FOR LAKE EFFECT SNOW SHOWERS...VIS WILL BE QUITE
VARIABLE...GENERALLY RANGING FROM MVFR TO IFR TODAY. LOWER VIS
SHOULD BE MORE COMMON TODAY INTO THIS EVENING AS OVERWATER
INSTABILITY INCREASES...RESULTING IN THE POTENTIAL OF INCREASED
-SHSN INTENSITY. SOME IMPROVEMENT IN VIS IS EXPECTED LATE TONIGHT AS
WINDS BACK MORE WNW AHEAD OF BUILDING HIGH PRES RDG DIMINISHING
SHSN...ESPECIALLY AT KIWD AND KSAW.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WINDS MOSTLY IN THE 10-20 KT RANGE THROUGH TUE AS A HIGH PRES
RIDGE OVER NORTHERN ONTARIO AND THE NRN PLAINS SLOWLY BUILDS ACROSS
LAKE SUPERIOR. AS THE RIDGE SLIPS SE OF THE LAKE AND A COLD
FRONT APPROACHES...SW WINDS WILL LIKELY INCREASE TO GALE FORCE TUE
NIGHT INTO EARLY WED...MAINLY OVER WESTERN AND NCNTRL LAKE SUPERIOR.
A WINTRY PATTERN OF W-NW WINDS WILL THEN PERSIST THRU LATE WEEK WITH
LAKE EFFECT SNOW SHOWERS. GIVEN ARCTIC AIR PASSING OVER THE
LAKE...EFFICIENT MIXING MAY RESULT IN BRIEF GALES AT TIMES LATE IN
THE WEEK. MAY NEED TO CONSIDER THE POTENTIAL OF FREEZING SPRAY AS
WELL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING FOR
LSZ266.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ162.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
DISCUSSION...MRD
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
547 AM CST MON DEC 5 2011
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
314 AM CST MON DEC 5 2011
MAIN FORECAST CONCERNS ARE ON SNOW SHOWERS/FREEZING DRIZZLE TODAY
AND WHEN CLOUDS CLEAR.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE EAST PACIFIC INTO SOUTHWEST CANADA...
TROUGHING FROM JAMES BAY SOUTHWEST INTO THE FOUR CORNERS REGION...
AND RIDGING ALONG THE EAST COAST OF THE U.S.. WITHIN THE UPPER
TROUGHING...THE MAIN FEATURE OF INTEREST IS A SHORTWAVE OVER EASTERN
SOUTH DAKOTA. WITH THIS SHORTWAVE...AREAS OF LIGHT SNOW WERE BEING
OBSERVED...WHICH WERE ALSO ALONG A WEAK NORTHWEST-SOUTHEAST ORIENTED
TROUGH THROUGH THE SIOUX FALLS AREA. FARTHER EAST...ANOTHER WEAK
SURFACE TROUGH WAS ANALYZED FROM NEAR EAU CLAIRE TO SHEBOYGAN WI.
CONVERGENCE ALONG THIS TROUGH COMBINED WITH LOW LEVEL MOISTURE IN
PLACE NOTED BY THE STRATUS DECK IS PRODUCING SCATTERED SNOW SHOWERS
AROUND THE TROUGH. THERE HAVE EVEN BEEN SOME FREEZING DRIZZLE
REPORTS...MOSTLY LAST EVENING THROUGH FAIRLY RECENTLY AT VOLK
FIELD...BECAUSE OF LACK OF ICE ISSUES. THE LACK OF ICE IS NOTED BY
THE 00Z GRB AND MPX SOUNDINGS WHICH WERE ONLY SATURATED TO -11 TO
-13C RESPECTIVELY. THE AFOREMENTIONED STRATUS IS QUITE
WIDESPREAD...ENCOMPASSING ALL OF WI...MUCH OF IOWA...THE EASTERN
DAKOTAS AND ALMOST ALL OF MINNESOTA. AS A RESULT OF THE CLOUD
COVER...TEMPERATURES HAVE STAYED MOSTLY IN THE 20S ALL NIGHT.
TODAY AND TONIGHT...SHORTWAVE OVER EASTERN SOUTH DAKOTA IS PROGGED
TO LIFT NORTHEAST ALONG THE EAST SIDE OF THE UPPER TROUGH...CROSSING
NORTHWEST WI AND THE U.P. THIS EVENING. THE TRACK OF THIS
SHORTWAVE...COMBINED WITH MODEL FORECASTS OF THE ASSOCIATED
SURFACE TROUGH BASICALLY DISSIPATING...SUGGESTS LIGHT SNOW WITH IT
SHOULD STAY AWAY FROM THE FORECAST AREA. MEANWHILE...THE SURFACE
TROUGH CURRENTLY PRODUCING THE LIGHT SNOW OVER CENTRAL WISCONSIN
IS FORECAST BY THE 05.00Z NAM/REGIONAL CANADIAN AND 05.06Z HRRR TO
DROP SOUTHWEST THROUGH THE DAY TODAY...POSSIBLY REACHING KLSE BY
00Z. BY THE TIME IT REACHES KLSE...ALL OF THESE MODELS HAVE IT
WEAKENING. THIS SEEMS REASONABLE DUE TO THE LARGE 1040MB SURFACE
HIGH OVER THE WESTERN DAKOTAS PROGGED TO MOVE INTO WESTERN
MINNESOTA...AND THAT IS IN RESPONSE TO THE UPPER TROUGH
APPROACHING THE AREA. THEREFORE...HAVE ONLY INCLUDED A BAND OF
20-30 PERCENT CHANCES ALONG THE SURFACE TROUGH TODAY. THIS
REFLECTS CURRENT RADAR TRENDS WELL TOO. AS FAR AS PRECIPITATION
TYPE GOES...MODEL SOUNDINGS INDICATE THE SAME SETUP AS NOW WITH
CLOUD TOP TEMPS AT MOST AROUND -11C. SINCE THE MAJORITY OF REPORTS
THUS FAR OVERNIGHT HAVE BEEN -SN...WILL CONTINUE THAT BUT MENTION
A CHANCE FOR FREEZING DRIZZLE SINCE -11C REPRESENTS ABOUT A 60
PERCENT CHANCE THAT ICE ACTUALLY EXISTS IN THE CLOUD PER AIRCRAFT
RESEARCH. CONFIDENCE CERTAINLY IS NOT HIGH ENOUGH TO ISSUE A
FREEZING RAIN ADVISORY...ESPECIALLY GIVEN THE MAJORITY OF SNOW
REPORTS. OTHERWISE...ONLY OTHER CONCERN IS THE STRATUS. NAM/RUC
HAVE BEEN DOING THE BEST THUS FAR IN THE LOW LEVEL RH PROGS
MATCHING UP WITH THE STRATUS. BOTH SUGGEST THE AREA STAYS CLOUDY
TODAY...WHICH MAKES SENSE WITH 925-950MB WINDS NORTHEAST TO NORTH.
TONIGHT...THERE COULD BE SOME BREAK UP...ESPECIALLY ALONG THE
NORTHWEST EDGE OF THE FORECAST AREA LATE TONIGHT AS 925MB WINDS
BACK TO THE NORTHWEST AT 12Z. GIVEN THE COLD NATURE OF THE AIRMASS
IN PLACE...ANY CLEARING COULD CAUSE TEMPERATURES TO TANK INTO THE
SINGLE DIGITS. MEANWHILE...CLOUDY AREAS WOULD STAY WARMER IN THE
TEENS AND 20S. NEEDLESS TO SAY...TRICKY LOW TEMPERATURE FORECAST
FOR TONIGHT. GENERALLY FOLLOWED A BLEND OF GUIDANCE FOR HIGHS
TODAY.
TUESDAY THROUGH WEDNESDAY NIGHT...UPPER LEVEL PATTERN IS FORECAST TO
UNDERGO SOME CHANGE DURING THIS PERIOD...IN RESPONSE TO A POWERFUL
UPPER LEVEL TROUGH DIGGING DOWN THROUGH CENTRAL CANADA. AS THIS
TROUGH DIGS SOUTHWARD IT WILL HELP TO PUSH THE TROUGH APPROACHING
THE AREA TONIGHT THROUGH ON TUESDAY...GIVE A BRIEF PERIOD OF UPPER
RIDGING ON TUESDAY NIGHT...THEN CAUSE THE UPPER FLOW TO TURN ZONAL
FOR THE REST OF THE PERIOD. AS THE UPPER TROUGH MOVES THROUGH THE
AREA ON TUESDAY...WHICH MEANS THE SURFACE RIDGE WILL DO THE SAME...
ANTICIPATING SKIES TO CLEAR NORTHWEST TO SOUTHEAST. ALTHOUGH MORE
SUN IS EXPECTED...THE 850MB TEMPS FALL TO -10 TO -12C...SO HIGHS
WILL ACTUALLY END UP COOLER THAN TODAY. MOSTLY CLEAR AND COOL
CONDITIONS CONTINUE TUESDAY NIGHT THANKS TO SUBSIDENCE UNDER THE
UPPER RIDGING. A 5-10 KT SOUTHWEST WIND WILL HELP KEEP TEMPERATURES
FROM TANKING BELOW ZERO TUESDAY NIGHT...THOUGH THE WIND IS EXPECTED
TO DROP WIND CHILLS INTO THE SINGLE DIGITS BELOW ZERO. A BRIEF WARM
UP IS FORECAST FOR WEDNESDAY WITH 850MB TEMPS CLIMBING UP TO AROUND
-6C AT 18Z. HOWEVER...A COLD FRONT COMING THROUGH THE ZONAL FLOW
LOOKS TO CROSS LATE IN THE DAY...BRINGING AN INCREASE OF MID-HIGH
CLOUDS BEHIND IT. AS WE GO THROUGH WEDNESDAY NIGHT...THE 05.00Z
GFS/CANADIAN/NAM ALL WANT TO PRODUCE SOME LIGHT PRECIPITATION OUT OF
THESE CLOUDS...LIKELY A RESULT OF SOME MID-LEVEL FRONTOGENESIS. NOT
QUITE SOLD ON THIS PRECIPITATION YET...ESPECIALLY WITH THE 05.00Z
ECMWF STILL DRY AND REALLY THE FIRST SIGNAL OF IT. THEREFORE...HAVE
ONLY INCREASED CLOUD COVER AT THIS TIME. THE CLOUDS SHOULD HELP KEEP
TEMPERATURES UP SOME WEDNESDAY NIGHT. FOLLOWED A BLEND OF GUIDANCE
THEN.
.LONG TERM...THURSDAY THROUGH SUNDAY NIGHT
314 AM CST MON DEC 5 2011
05.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES REMAIN IN PRETTY GOOD
AGREEMENT FOR THE LONG TERM FORECAST...BOTH BETWEEN EACH RUN AND
WHAT WAS SEEN YESTERDAY...LEADING TO ABOVE AVERAGE CONFIDENCE. A
SHORTWAVE TROUGH COMING AROUND THE POWERFUL CENTRAL CANADA TROUGH IS
PROGGED TO DROP INTO THE NORTHERN PLAINS THURSDAY...CROSSING THE
AREA THURSDAY NIGHT INTO FRIDAY. THERE REMAINS SOME SIGNALS OF A
MID-LEVEL FRONTOGENESIS BAND AND UPPER JET INDUCED PRECIPITATION AS
THIS SHORTWAVE TROUGH APPROACHES THE AREA. HOWEVER...A CONSENSUS OF
THE MODELS HAS SHOWN A SHIFT SOUTH...SUCH THAT IT CROSSES MOSTLY THE
SOUTHERN HALF OF IOWA AND NORTHERN ILLINOIS DURING THURSDAY NIGHT.
NOTE...THE NEW 05.00Z ECMWF HAS SHIFTED BACK NORTH...BUT NOT ENOUGH
CONFIDENCE EXISTS TO PUT CHANCES FARTHER NORTH YET. AFTER THIS...IT
LOOKS LIKE A SOLID DRY FORECAST HEADING INTO THE WEEKEND AS THE
UPPER FLOW TRANSITIONS TO ZONAL. SHOULD SEE A WARMING TREND TOO AS
DOWNSLOPING MOTION OFF THE ROCKIES OF PACIFIC AIR CAUSES
TEMPERATURES TO MODIFY. SO AFTER A CHILLY FRIDAY AND FRIDAY NIGHT
WITH 850MB TEMPS PROGGED AS COLD AS -20C...THESE WILL WARM UP
DRAMATICALLY...REACHING TO 0 TO +2C BY SUNDAY. LOOKING
BEYOND...RIGHT NOW IT APPEARS ABOVE NORMAL TEMPERATURES COULD
PERSIST INTO THE EARLY PORTION OF NEXT WEEK WITH ZONAL FLOW
CONTINUING.
&&
.AVIATION...TODAY THROUGH TUESDAY
547 AM CST MON DEC 5 2011
CONSIDERABLE MOISTURE IN THE 925-850MB LAYERS REMAINS ACROSS MN/IA/
WI...TRAPPED UNDER AN INVERSION NEAR 800MB. WITH WEAK GRADIENTS/
LIGHT WINDS IN THE SFC-800MB LAYER...THIS MOISTURE AND RESULTING
MVFR/ LCL VFR STRATUS CLOUDS WILL BE RATHER PERSISTENT ACROSS THE
AREA TODAY INTO TONIGHT. A WEAK SHORTWAVE DROPPING ACROSS THE
WESTERN GREAT LAKES REGION TODAY WILL PROVIDE SOME WEAK CONVERGENCE/
LIFT FOR PATCHY -SN/-FZDZ OR -SHSN. WITH LIMITED COVERAGE EXPECTED
FOR ANY PRECIP AND VSBYS REMAINING 6SM OR GREATER DID NOT INCLUDE
-SN OR -FZDZ IN THE TAFS AT THIS TIME. DRIER HIGH PRESSURE BEGINS TO
BUILD INTO TONIGHT...WITH DECREASING/CLEARING CLOUDS THRU THE NIGHT
WEST/NORTH OF A KOMA-KMSP-KDLH LINE. QUESTION IS HOW QUICKLY WILL
THIS LOW CLOUD CLEARING PROGRESS EAST TOWARD/ACROSS THE TAF SITES
LATER TONIGHT/TUE. GIVEN THE GENERAL TENACITY OF LOW CLOUD DECKS AT
THIS TIME OF YEAR...KEPT BKN MVFR CIGS AT BOTH KRST/KLSE THRU 12Z
TUE. HOWEVER DID GRADUALLY RAISE CIGS THIS AFTERNOON/TONIGHT AS
THE DRIER AIR ON THE LEADING EDGE OF THE HIGH SLOWLY FILTERS INTO
THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 AM CST MON DEC 5 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1024 AM CST MON DEC 5 2011
.DISCUSSION...
340 AM CST
CHILLY NORTHWEST FLOW AND A PLETHORA OF CLOUDS WILL BE THE MAIN
STORY FOR TODAY ACROSS THE CWA. AT THE SURFACE HIGH PRESSURE WILL
SLOWLY BUILD SOUTH FROM THE UPPER MISSISSIPPI VALLEY OVER THE NEXT
FEW DAYS AS AN INVERTED TROUGH STRETCHES NORTH FROM THE WESTERN
GULF...THROUGH WESTERN KENTUCKY THIS MORNING. THE MAIN PRECIP
BANDING THAT MOVE THROUGH YESTERDAY IS HANGING AROUND THE VICINITY
OF THE INV TROF/STALLED OUT FRONTAL BOUNDARY. A FEW WIGGLES IN THE
FLOW ARE NOTED ON WV IMAGERY MOVING UP THE BOUNDARY...BUT THE
OVERALL BEST CHANCES FOR PRECIP WILL REMAIN WELL TO THE SOUTHEAST. THAT
SAID...A WEAK CONVERGENT BOUNDARY STRETCHING FROM NORTHWESTERN
WI...SOUTHEAST TOWARDS THE SOUTHERN LAKE WILL CONTINUE TO SLIDE
SOUTH THROUGH THE DAY...BRINGING CHANCES FOR LIGHT SNOW SHOWERS TO THE
NORTH AND NORTHWESTERN COUNTIES. OVERALL MOISTURE PROFILES ARE
SHALLOW...BUT POTENTIALLY SUPPORTIVE OF DRIZZLE...AND WITH SURFACE
TEMPS AT OR BELOW FREEZING...WOULDNT BE SURPRISED TO SEE SOME U.P.
AND OR -FZDZ REPORTS ACROSS THE FAR NORTHWESTERN COUNTIES THIS
MORNING. SURFACE TEMPERATURES MAY FLIRT ENOUGH WITH FREEZING THAT
IMPACTS WOULD BE LIMITED TO EXPOSED AND ELEVATED SURFACES.
BEHIND THE CONVERGENT BOUNDARY...FLOW WILL BECOME NORTHEASTERLY AND
INCREASE THE CHANCES FOR LAKE EFFECT SNOWS ACROSS NE IL. BUFR AND
MODEL GUIDANCE MAINTAIN A NORTHEASTERLY COMPONENT IN THE LOWEST
200 MB... WITH SATURATION AND LAKE INDUCED CAPES UP TO 6KFT
THROUGH TOMORROW AFTERNOON. THIS IS A LITTLE DIFFERENT FROM
PREVIOUS DAYS /IE SLOWER/...AS THE AREA OF HIGH PRESSURE ACROSS
THE PLAINS SLOWLY DROPS SOUTH...AND WOULD BE SLUGGISH AT
TRANSITIONING THE SNOWS INTO THE TYPICAL LAKE/PORTER COUNTY
INDIANA LOCATIONS. LATEST COBB OUTPUT DOES SQUEEZE OUT JUST UNDER
A HALF INCH OF SNOW FOR AREAS IN LAKE AND COOK COUNTY. OVERNIGHT
TONIGHT AND INTO TOMORROW...ANY LES SHOULD BEGIN AS SNOW...BUT
PROFILES ARE WARMING THE SURFACE TO ABOVE FREEZING INTO THE
MORNING HOURS. DEW POINT DEPRESSIONS NOT PROGGED TO BE VERY HIGH
SO EXPECT WET BULBS AT THE SURFACE TO REMAIN JUST AOA FREEZING
INTO THAT TIME. SO EXPECT TRANSITION TO SNOW WITH A MIX OF
RAIN...BUT DEPENDING ON HOW SLUGGISH PROFILES ARE TO WARM AT THE
SURFACE...IT MAY REMAIN MORE FROZEN THAN ANYTHING WITH SOME
SPRINKLES MIXED IN. THE LATEST IN HOUSE AND NATIONAL WRF /NMM AND
ARW/ DEVELOP THIS BOUNDARY LATE TONIGHT ALONG THE LAKE/COOK LAKE
SHORE BEYOND 06Z TONIGHT. OVERALL QPF VALUES ARE PRETTY LOW AND
RANGE FROM 0.02 TO 0.05". GIVEN THE FACT THAT TEMPS ARE NOT TOO
COLD...SNOW TO LIQUID RATIOS SHOULD BE PRETTY TYPICAL 10:1 AND NOT
HIGHER...BUT LIKELY A SMIDGEN LOWER. SO ANTICIPATING NO MORE THAN
A QUARTER OF AN INCH TO MAYBE A HALF OF AN INCH IN SOME OF THE
INTENSE SHOWERS THAT WIGGLE THROUGH. ONE INTERESTING FEATURE
TONIGHT IS THAT THE REGIONAL GEM DEVELOPS A WEAK MESO LOW ACROSS
THE SOUTHERN HALF OF THE LAKE...DUMPING 4+ INCHES OF SNOW ACROSS
RACINE/KENOSHA/LAKE AND EVEN MCHENRY COUNTIES TONIGHT AND INTO
TOMORROW MORNING. THE PREVIOUS RGEM RUNS SHOWED SIMILAR
OUTCOMES... BUT MORE ACROSS LAKE COUNTY INDIANA/COOK COUNTY AND
NOWHERE NEAR AS INTENSE AS THE CURRENT RUN. WILL MONITOR TO SEE IF
TRENDS LEAN IN A HIGHER DIRECTION BUT FOR NOW WILL KEEP IT IN THE
SUB HALF IN RANGE.
A PRACTICALLY STATIONARY UPPER LEVEL TROUGH ACROSS THE WESTERN
CONUS WILL BEGIN TO SWING BEYOND THE REGION OVERNIGHT TUESDAY AND
INTO WEDNESDAY WHILE RIDGING AT THE SURFACE BUILDS. CONDITIONS
ACROSS THE AREA SHOULD REMAIN QUIET THROUGH THE END OF WITH WEEK.
OVERNIGHT ON THURSDAY A WEAK CLIPPER WILL ZIP THROUGH THE REGION
AND BRING THE CHANCES FOR A QUICK DUSTING OF SNOW. GUIDANCE IS
STILL GOING BACK AND FORTH ON HOW MUCH TO HANDLE A DIGGING TROUGH
AND SHEARED OUT VORT THAT WILL DIP THROUGH THE NORTHERN PLAINS IN
THAT TIME. THE 00Z GFS IS MOVING THROUGH THE CWA DRY WHILE THE ECMWF
HAS BEEN PRETTY CONSISTENT TO SHOW SOME -SN INTO THE EARLY
AFTERNOON HOURS. WITH THE VARIABILITY AT THIS RANGE WILL LIMIT
MENTION TO ONLY A SLIGHT CHANCE. IF/WHEN TRENDS ALIGN...WILL NUDGE
UPWARDS. THE OTHER SEMI-CONSISTENT STORY BEYOND THE TROUGH AND
INTO FRIDAY/THE WEEKEND IS THE SURGE OF COLD AIR SPILLING IN FROM
CANADA. THERE IS STILL A STRONG INDICATION THAT H85 TEMPS WILL
DROP ANYWHERE FROM -15 TO -20. THE EC HAS CONTINUALLY BEEN THE
MOST AGGRESSIVE OVER THE LAST FEW NIGHTS...WHILE THE GFS HAS BEEN
SCALING BACK SLIGHTLY. RAW GUIDANCE SUGGESTS MAX TEMPS MAY
STRUGGLE TO WARM ABOVE THE LOW 20S FRI...BUT WONDER IF THAT MAY BE
A LITTLE TOO WARM. THE BIG SAVING GRACE IS THE LACK OF SOLID SNOW
PACK...IF THAT WERE PRESENT...IT WOULD BE MUCH COLDER. THE DIP TO
COLD TEMPS SHOULD BE SHORT LIVED AS A THERMAL RIDGE IS PROGGED TO
BUILD IN LATE ON THE WEEKEND AS FLOW FLIPS TO SOUTHWESTERLY
THROUGH THE COLUMN. SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CEILING TRENDS TODAY.
* LAKE EFFECT SHOWERS LATE MORNING THROUGH EARLY AFTERNOON.
TRS
//DISCUSSION...UPDATED 16Z...
INITIAL BAND OF LAKE EFFECT SHOWERS HAVE WEAKENED AS THEN MOVED
INLAND OVER FAR SE WI...EXTREME NE IL AND FAR NW IND. ANOTHER BAND
OF LAKE EFFECT IS CURRENTLY MOVING ASHORE IN NE IL AND FAR SE WI
WHERE LOW LEVEL CONVERGENCE ALONG A SFC TROF AND WSHFT LINE.
LATEST RUNS OF HRRR AND RUC13 HAVE DELAYED THE ARRIVAL OF THE
WSHFT AND THE AXIS OF MAX SFC CONVERGENCE AT ORD AND MDW BY AN HR
OR TWO. EXTRAPOLATION OF MOVEMENT OF LAKE BAND OVER LAST HR OR SO
HAS PUSHED ARRIVAL AT ORD SLIGHTLY THOUGH NOT AS SLOW AS MODELS
INDICATE. WITH SRN MID LAKE BUOY REPORTING 41F FOR BOTH AIR AND
WATER TEMPS ALONG WITH NORTHERLY ISLAND AT 41F WITH DWPT 33F
EXPECT TO SEE -SHRA OR -SHSNRA DO TO WARM LLVLS...ESPECIALLY OVER
CORE OF URBAN AREA. ALSO FCST TEMP PROFILES KEEPING LAKE EFFECT
CLOUD TOPS NO COLDER THAN -6 TO -7 C...TOO WARM FOR VERY MANY ICE
CRYSTALS. THESE FORECAST TEMPS VERIFIED BY RECENT AIRCRAFT TEMP
PROFILES FROM ORD ARRIVALS AND DEPARTURES.
BASED ON TRENDS JUST UPSTREAM OVER SE WI AND EXTREME NE IL EXPECT
TO SEE MVFR CIGS CONTINUE FURTHER SOUTH AND LOWER A BIT AND ALSO
SOME REDUCTION OF VSBY TO MVFR IN SHOWERS. SMALL AREA OF IFR
CIGS PERSIST OVER PARTS OF FAR SE WI THOUGH HAVE PUSHED INLAND
FROM MKE...RAC AND ENW. MAY BRIEFLY EXPERIENCE IFR CIGS AT ORD
AND MDW AROUND TIME OF THE WSHFT TO OUT OF THE NNE.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE ON CEILING TRENDS AND VISIBILITY TRENDS.
* MEDIUM CONFIDENCE ON TIMING AND COVERAGE OF LAKE EFFECT SHOWERS.
* HIGH CONFIDENCE ON GENERAL WIND SPEEDS AND DIRECTIONS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY...VFR. CHANCE OF SNOW SHOWERS NEAR THE LAKE.
WEDNESDAY...VFR.
THURSDAY...VFR. SLIGHT CHANCE OF SNOW SHOWERS THURSDAY NIGHT.
FRIDAY THROUGH SUNDAY...VFR.
LENNING
&&
.MARINE...
309 AM CST
HIGH PRESSURE QUICKLY SPREADING ACROSS THE NORTHERN AND CENTRAL
PLAINS TODAY WHILE A TROUGH OF LOW PRESSURE EXTENDING FROM QUEBEC TO
THE TEXAS GULF COAST MORE SLOWLY MOVES EAST...THE PRESSURE GRADIENT
WILL STRENGTHEN OVER LAKE MICHIGAN LEADING TO INCREASING GENERALLY
NORTHERLY WINDS. THIS WILL ALSO INCREASE COLD ADVECTION OVER THE
LAKE...DRIVING WAVE HEIGHTS TO INCREASE QUICKLY AS WINDS INCREASE
TO 15 TO 25 KT. WHILE NO GALES ARE EXPECTED TO DEVELOP AT THIS
TIME...WAVES PILING UP AT THE SOUTHERN END OF THE LAKE WILL LEAD TO
WINDS AND WAVES HAZARDOUS TO SMALL CRAFT DEVELOPING BY EARLY THIS
AFTERNOON. WITH THE HIGH PRESSURE SLOWLY BUILDING TO THE EAST...THE
SMALL CRAFT ADVISORY CONDITION WILL PERSIST FOR THE NEARSHORE
WATERS THROUGH TUESDAY EVENING. THROUGH TUESDAY NIGHT...THE SFC
HIGH WILL BUILD ACROSS THE LAKE...ALLOWING WINDS AND WAVES TO
SUBSIDE. THIS HIGH PRESSURE IS EXPECTED TO PUSH SOUTHEAST OF THE
LAKE BY WEDNESDAY...ALLOWING WINDS TO BRIEFLY TURN
SOUTHWESTERLY...BUT A COLD FRONT DROPPING OUT OF CENTRAL CANADA WILL
QUICKLY TURN THE WINDS BACK NORTHWESTERLY WHILE INCREASING TO AROUND
30KT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 PM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
500 PM CST MON DEC 5 2011
.AVIATION...
FOR THE 00Z TAF ISSUANCE...
PERIODS OF LIGHT SNOW WILL BE POSSIBLE ACROSS CENTRAL AND PORTIONS
OF WESTERN KANSAS TONIGHT...MAINLY SOUTHEAST OF A KHYS TO KDDC LINE.
MVFR CIGS/VSBYS ARE LIKELY IN THE VICINITY OF ALL TAF SITES EARLY
THIS EVENING WITH BRIEF PERIODS OF IFR CIGS POSSIBLE IN THE
VICINITY AND SOUTHEAST OF KDDC THROUGH LATE THIS EVENING. VFR
CONDITIONS WILL GRADUALLY RETURN ACROSS THE AREA LATE TONIGHT AS
THE LOW LEVEL STRATUS MIGRATES EASTWARD THROUGH EARLY TUESDAY
MORNING. SURFACE HIGH PRESSURE WILL PREVAIL ACROSS THE NORTHERN
ROCKIES TONIGHT INFLUENCING NORTHERLY WINDS 5 TO 10KT THROUGH
EARLY TUESDAY MORNING. A LEE SIDE TROUGH OF LOW PRESSURE WILL
DEVELOP ACROSS EASTERN COLORADO TUESDAY MORNING TURNING WINDS
WESTERLY 5 TO 10KT BY EARLY TUESDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 340 PM CST MON DEC 5 2011/
SYNOPSIS...
THE 15.12Z 250 HPA MAP CONTINUED TO SHOW A LARGE TROUGH BISECTING THE
CONUS WITH A STRONG 100 KT JET EXTENDING SOUTHWARD FROM SASKATCHEWAN
AND ACROSS MONTANA. AN EVEN FASTER JET NEAR 150 KT WAS MOVING ACROSS
SE CANADA WITH AN EXTENSION OF THIS JET, ALBEIT WEAKER WINDS, TOWARDS
KANSAS. AT 500 HPA, VERY COLD AIR OF -40 DEG C WAS OBSERVED AT KABR
WITH -30S DEG C SOUTHWARD ACROSS COLORADO. THE ARCTIC AIR AT 700 HPA
WITH TEMPERATURES AT LEAST -20 DEG C EXTENDED ACROSS THE NORTHERN PLAINS.
5 DEGREES OF COOLING WAS NOTED BETWEEN THE 00Z AND 12Z RAOB FOR KDDC
AT 850 HPA. AT THE SURFACE, ARCTIC AIR EXTENDED ACROSS THE PLAINS WITH
TEENS AND 20S DEG F CONTINUING AT 21Z ACROSS THE SUNFLOWER STATE. -SUGDEN
DISCUSSION...
DAYS 1-2...
TONIGHT:
THE VERY SHORT TERM CONCERN FOR THIS EVENING IS THE SNOW POTENTIAL ACROSS
THE CENTRAL AND SOUTHERN HALF OF THE CWFA WITH A MORE APPRECIABLE CHANCE
FOR "HEAVIER" SNOW ACROSS THE SE CWFA. THE SATELLITE WATER VAPOR CHANNEL
SHOWS A WEAK DISTURBANCE MOVING NEW MEXICO AT THE BASE OF AN UPPER LEVEL
TROUGH. A PV ANOMALY ASSOCIATED WITH THE PASSAGE OF THE UPPER LEVEL
TROUGH AND ISENTROPIC LIFT IN THE 290-295K THETA LAYER WILL PROVIDE
ENOUGH LIFT FOR SOME SNOW SHOWERS, PARTICULARLY ACROSS THE SE FA. AS
A RESULT, HAVE INCREASED POPS UP TO CHANCE AND UPPED SNOWFALL AMOUNTS
TO 0.6-1.0 INCHES TOWARDS MEDICINE LODGE. HRRR ALSO IS SHOWING SOME ACCUMULATIONS
WHICH AGREES WITH THE QPF OUTPUT FROM THE THE NAM, GFS, GEM, ECMWF,
ARW, AND NMM...WHICH ALL PAINT A LITTLE QPF IN THIS REGION. OTHERWISE,
MID AND LOW LEVEL CLOUDS WILL EVENTUALLY CLEAR TONIGHT AS THE COLD SURFACE
HIGH PRESSURE CENTER SETTLES ACROSS KANSAS AND THE TROF CONTINUES EAST.
THIS WILL RESULT IN WEAKENING OF WINDS AND ALLOW TEMPERATURES TO PLUMMET.
I HAVE -2 TO -4 DEG F TO THE NORTHWEST AND AROUND 16 DEG F SE AS THE
NW WILL HAVE WEAKER WINDS AND LESS CLOUD COVER THAN COMPARED TO THE
SE. HAVE CONTINUED THE TREND OF HIGHLIGHTING THE LOW WIND CHILL VALUES
IN THE HWO. THESE VALUES ARE NOT EXPECTED TO REACH WIND CHILL ADVISORY
CRITERIA.
TUESDAY:
HAVE ZERO POPS IN TUESDAY AS THE CWFA WILL BE ON THE BACKSIDE (SUBSIDENCE)
OF THE UPPER LEVEL TROUGH AND HIGH PRESSURE WILL CONTINUE AT THE SURFACE.
THINK THE NAM MODEL IS BEING TOO INFLUENCED BY THE SNOWFIELD ACROSS
WEST CENTRAL AND NORTHWEST KANSAS SO HAVE STEERED AWAY FROM THIS RUN.
TEMPERATURES WILL SLIGHTLY MODERATE COMPARED TO MONDAYS HIGHS AND BE
IN THE 20S DEG F. BY TOMORROW EVENING, A WEAK LEE SURFACE TROUGH WILL
DEVELOP ACROSS EASTERN COLORADO WHICH WILL TURN OUR WINDS MORE SOUTHWESTERLY
TO WESTERLY. SKIES SHOULD BE CLEAR WITH A DRY AIRMASS OVERHEAD.
WEDNESDAY:
THE DAY WILL START COLD WITH SINGLE DIGITS TO LOW TEENS DEG F DURING
THE MORNING. DURING THE DAY, THE WEAK LEE SIDE TROUGH WILL MOVE EASTWARDS
ACROSS WESTERN KANSAS USHERED BY A SHORTWAVE TROUGH MOVING ACROSS THE
NORTHERN PLAINS. THIS WILL TURN OUR WINDS MORE NORTHWESTERLY SO WE COULD
SEE SOME DOWNSLOPE CONDITIONS AND RESULT WARMER TEMPERATURES. MEX GUIDANCE
HAS KDDC IN THE 40S AND THE ECMWF IS PARTICULARLY WARM WITH MID 40S
DEG F ACROSS THE CENTRAL AND SE FA. HAVE NOT WARMED TEMPERATURES UP
TO THIS BUT DID TWEAK THEM UP HIGHER WEDNESDAY. -SUGDEN
DAYS 3-7...
A SPLIT JET STREAM IS EXPECTED TO PREVAIL ACROSS THE CONUS WITH BENIGN
WEATHER AS A RESULT THROUGH THE EXTENDED FORECAST.
WEDNESDAY NIGHT THROUGH FRIDAY:
A NORTHWEST TO SOUTHEAST ORIENTED SURFACE HIGH WILL MOVE THROUGH THE
NORTHERN PLAINS THURSDAY AS A SHORTWAVE TROUGH IN THE NORTHERN BRANCH
OF THE JET SWINGS SOUTHEASTWARD AROUND THE SOUTHERN EDGE OF THE LARGER
HUDSON BAY GYRE. ANY NORTHWEST FLOW FRONTOGENESIS AND ATTENDANT SNOW
TIED TO THIS FEATURE WILL BE NORTH AND EAST OF THE SOUTHWEST KANSAS
REGION SO NO POPS ARE IN THE FORECAST. A GLANCING BLOW OF ARCTIC AIR
WILL ONLY RESULT IN A MINIMAL IMPACT ON TEMPERATURES WITH HIGHS GENERALLY
IN THE UPPER 30S FOR BOTH THURSDAY AND FRIDAY.
SATURDAY THROUGH MONDAY:
THE NORTHERN POLAR JET WILL BE SHIFTED NORTH DURING THIS TIME FRAME
WITH VERY WEAK FLOW IN THE MID AND UPPER LEVELS OVER THE CENTRAL ROCKIES
AND GREAT PLAINS. MEANWHILE...THE SOUTHERN JET WILL REMAIN ALONG AN
AXIS FROM THE NORTHERN BAJA OF CALIFORNIA THROUGH SOUTHWEST TEXAS TO
THE GULF COAST REGION. THE DETERMINISTIC GFS AND ECMWF MODELS BOTH
SHOW A MINOR SHORTWAVE TROUGH WITHIN THE SOUTHERN JET MOVING ACROSS
SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA ENTERING THE DESERT SOUTHWEST
REGION. A JET STREAM IN THE NORTHERN POLAR JET IS EXPECTED TO DIG SOUTHWARD
DOWN THE WEST COAST AROUND SUNDAY...WHICH WILL BECOME INVOLVED WITH
THE SOUTHERN JET IN SOME FASHION. INTERACTION OF SOUTHERN AND NORTHERN
BRANCHES OF THE JET IS SOMETHING THAT MODELS WILL STRUGGLE WITH AT THIS
TIME FRAME...SO THERE IS A LOT OF UNCERTAINTY GOING INTO LATE WEEKEND/EARLY
NEXT WEEK CONCERNING HOW A POTENTIAL MEAN TROUGH IN THE WEST WILL EVOLVE...AND
JUST HOW IT WILL IMPACT SOUTHWEST KANSAS WEATHER AS A RESULT. -UMSCHEID
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 8 27 10 41 / 20 0 0 0
GCK 4 24 8 39 / 10 0 0 0
EHA 6 25 9 41 / 20 0 0 0
LBL 8 27 9 41 / 20 0 0 0
HYS 7 24 9 37 / 10 0 0 0
P28 16 30 14 42 / 40 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN32/99/99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
340 PM CST MON DEC 5 2011
.SYNOPSIS...
THE 15.12Z 250 HPA MAP CONTINUED TO SHOW A LARGE TROUGH BISECTING THE
CONUS WITH A STRONG 100 KT JET EXTENDING SOUTHWARD FROM SASKATCHEWAN
AND ACROSS MONTANA. AN EVEN FASTER JET NEAR 150 KT WAS MOVING ACROSS
SE CANADA WITH AN EXTENSION OF THIS JET, ALBEIT WEAKER WINDS, TOWARDS
KANSAS. AT 500 HPA, VERY COLD AIR OF -40 DEG C WAS OBSERVED AT KABR
WITH -30S DEG C SOUTHWARD ACROSS COLORADO. THE ARCTIC AIR AT 700 HPA
WITH TEMPERATURES AT LEAST -20 DEG C EXTENDED ACROSS THE NORTHERN PLAINS.
5 DEGREES OF COOLING WAS NOTED BETWEEN THE 00Z AND 12Z RAOB FOR KDDC
AT 850 HPA. AT THE SURFACE, ARCTIC AIR EXTENDED ACROSS THE PLAINS WITH
TEENS AND 20S DEG F CONTINUING AT 21Z ACROSS THE SUNFLOWER STATE. -SUGDEN
&&
.DISCUSSION...
DAYS 1-2...
TONIGHT:
THE VERY SHORT TERM CONCERN FOR THIS EVENING IS THE SNOW POTENTIAL ACROSS
THE CENTRAL AND SOUTHERN HALF OF THE CWFA WITH A MORE APPRECIABLE CHANCE
FOR "HEAVIER" SNOW ACROSS THE SE CWFA. THE SATELLITE WATER VAPOR CHANNEL
SHOWS A WEAK DISTURBANCE MOVING NEW MEXICO AT THE BASE OF AN UPPER LEVEL
TROUGH. A PV ANOMALY ASSOCIATED WITH THE PASSAGE OF THE UPPER LEVEL
TROUGH AND ISENTROPIC LIFT IN THE 290-295K THETA LAYER WILL PROVIDE
ENOUGH LIFT FOR SOME SNOW SHOWERS, PARTICULARLY ACROSS THE SE FA. AS
A RESULT, HAVE INCREASED POPS UP TO CHANCE AND UPPED SNOWFALL AMOUNTS
TO 0.6-1.0 INCHES TOWARDS MEDICINE LODGE. HRRR ALSO IS SHOWING SOME ACCUMULATIONS
WHICH AGREES WITH THE QPF OUTPUT FROM THE THE NAM, GFS, GEM, ECMWF,
ARW, AND NMM...WHICH ALL PAINT A LITTLE QPF IN THIS REGION. OTHERWISE,
MID AND LOW LEVEL CLOUDS WILL EVENTUALLY CLEAR TONIGHT AS THE COLD SURFACE
HIGH PRESSURE CENTER SETTLES ACROSS KANSAS AND THE TROF CONTINUES EAST.
THIS WILL RESULT IN WEAKENING OF WINDS AND ALLOW TEMPERATURES TO PLUMMET.
I HAVE -2 TO -4 DEG F TO THE NORTHWEST AND AROUND 16 DEG F SE AS THE
NW WILL HAVE WEAKER WINDS AND LESS CLOUD COVER THAN COMPARED TO THE
SE. HAVE CONTINUED THE TREND OF HIGHLIGHTING THE LOW WIND CHILL VALUES
IN THE HWO. THESE VALUES ARE NOT EXPECTED TO REACH WIND CHILL ADVISORY
CRITERIA.
TUESDAY:
HAVE ZERO POPS IN TUESDAY AS THE CWFA WILL BE ON THE BACKSIDE (SUBSIDENCE)
OF THE UPPER LEVEL TROUGH AND HIGH PRESSURE WILL CONTINUE AT THE SURFACE.
THINK THE NAM MODEL IS BEING TOO INFLUENCED BY THE SNOWFIELD ACROSS
WEST CENTRAL AND NORTHWEST KANSAS SO HAVE STEERED AWAY FROM THIS RUN.
TEMPERATURES WILL SLIGHTLY MODERATE COMPARED TO MONDAYS HIGHS AND BE
IN THE 20S DEG F. BY TOMORROW EVENING, A WEAK LEE SURFACE TROUGH WILL
DEVELOP ACROSS EASTERN COLORADO WHICH WILL TURN OUR WINDS MORE SOUTHWESTERLY
TO WESTERLY. SKIES SHOULD BE CLEAR WITH A DRY AIRMASS OVERHEAD.
WEDNESDAY:
THE DAY WILL START COLD WITH SINGLE DIGITS TO LOW TEENS DEG F DURING
THE MORNING. DURING THE DAY, THE WEAK LEE SIDE TROUGH WILL MOVE EASTWARDS
ACROSS WESTERN KANSAS USHERED BY A SHORTWAVE TROUGH MOVING ACROSS THE
NORTHERN PLAINS. THIS WILL TURN OUR WINDS MORE NORTHWESTERLY SO WE COULD
SEE SOME DOWNSLOPE CONDITIONS AND RESULT WARMER TEMPERATURES. MEX GUIDANCE
HAS KDDC IN THE 40S AND THE ECMWF IS PARTICULARLY WARM WITH MID 40S
DEG F ACROSS THE CENTRAL AND SE FA. HAVE NOT WARMED TEMPERATURES UP
TO THIS BUT DID TWEAK THEM UP HIGHER WEDNESDAY. -SUGDEN
DAYS 3-7...
A SPLIT JET STREAM IS EXPECTED TO PREVAIL ACROSS THE CONUS WITH BENIGN
WEATHER AS A RESULT THROUGH THE EXTENDED FORECAST.
WEDNESDAY NIGHT THROUGH FRIDAY:
A NORTHWEST TO SOUTHEAST ORIENTED SURFACE HIGH WILL MOVE THROUGH THE
NORTHERN PLAINS THURSDAY AS A SHORTWAVE TROUGH IN THE NORTHERN BRANCH
OF THE JET SWINGS SOUTHEASTWARD AROUND THE SOUTHERN EDGE OF THE LARGER
HUDSON BAY GYRE. ANY NORTHWEST FLOW FRONTOGENESIS AND ATTENDANT SNOW
TIED TO THIS FEATURE WILL BE NORTH AND EAST OF THE SOUTHWEST KANSAS
REGION SO NO POPS ARE IN THE FORECAST. A GLANCING BLOW OF ARCTIC AIR
WILL ONLY RESULT IN A MINIMAL IMPACT ON TEMPERATURES WITH HIGHS GENERALLY
IN THE UPPER 30S FOR BOTH THURSDAY AND FRIDAY.
SATURDAY THROUGH MONDAY:
THE NORTHERN POLAR JET WILL BE SHIFTED NORTH DURING THIS TIME FRAME
WITH VERY WEAK FLOW IN THE MID AND UPPER LEVELS OVER THE CENTRAL ROCKIES
AND GREAT PLAINS. MEANWHILE...THE SOUTHERN JET WILL REMAIN ALONG AN
AXIS FROM THE NORTHERN BAJA OF CALIFORNIA THROUGH SOUTHWEST TEXAS TO
THE GULF COAST REGION. THE DETERMINISTIC GFS AND ECMWF MODELS BOTH
SHOW A MINOR SHORTWAVE TROUGH WITHIN THE SOUTHERN JET MOVING ACROSS
SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA ENTERING THE DESERT SOUTHWEST
REGION. A JET STREAM IN THE NORTHERN POLAR JET IS EXPECTED TO DIG SOUTHWARD
DOWN THE WEST COAST AROUND SUNDAY...WHICH WILL BECOME INVOLVED WITH
THE SOUTHERN JET IN SOME FASHION. INTERACTION OF SOUTHERN AND NORTHERN
BRANCHES OF THE JET IS SOMETHING THAT MODELS WILL STRUGGLE WITH AT THIS
TIME FRAME...SO THERE IS A LOT OF UNCERTAINTY GOING INTO LATE WEEKEND/EARLY
NEXT WEEK CONCERNING HOW A POTENTIAL MEAN TROUGH IN THE WEST WILL EVOLVE...AND
JUST HOW IT WILL IMPACT SOUTHWEST KANSAS WEATHER AS A RESULT. -UMSCHEID
&&
.AVIATION...
FOR THE 18Z TAF ISSUANCE...THE MAIN CHALLENGE CONCERNING AVIATION WEATHER
IS HOW LOW CEILINGS WILL GET LATER ON TODAY AND THIS EVENING AS AN UPPER
LEVEL WAVE MOVES ACROSS THE SOUTHERN PLAINS. OBSERVATIONS AS OF 17Z
SHOWED GENERALLY VFR CEILING (AROUND 7-9KFT) ACROSS SOUTHWEST KANSAS...HOWEVER
OVER THE TEXAS PANHANDLE...IFR AND LIFR WERE REPORTED WITH SNOW. THE
SNOW AXIS WILL SHIFT NORTHEAST TONIGHT...BUT IS EXPECTED TO REMAIN SOUTH
OF ALL THREE TERMINALS (DDC, GCK, HYS)...THEREFORE WILL KEEP SNOW OUT
OF THE TERMINALS. WILL BE FORECASTING MVFR CATEGORY BY LATE AFTERNOON...AND
ONLY BRING IN IFR CEILING (900 FOOT) AT DDC CLOSER TO THE SNOW AXIS
AND UPWARD VERTICAL MOTION TIED TO THE STORM SYSTEM. BY LATE TONIGHT/EARLY
TUESDAY MORNING...CEILING WILL GRADUALLY DISSIPATE AND VFR CONDITIONS
WILL RESUME BY 09-12Z TUESDAY TIME FRAME. -UMSCHEID
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 8 27 10 41 / 20 0 0 0
GCK 4 24 8 39 / 10 0 0 0
EHA 6 25 9 41 / 20 0 0 0
LBL 8 27 9 41 / 20 0 0 0
HYS 7 24 9 37 / 10 0 0 0
P28 16 30 14 42 / 40 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN36/25/25
AREA FORECAST DISCUSSION
NWS GOODLAND KS
221 PM MST MON DEC 5 2011
.DISCUSSION...
221 PM MST MON DEC 5 2011
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE SCALE
TROUGH EXTENDING FROM GREAT LAKES REGION...ACROSS CENTRAL
COLORADO...WITH BASE OF TROUGH OVER SOUTHERN ARIZONA/NEW MEXICO.
THROUGH TONIGHT...SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD OVER
THE CENTRAL HIGH PLAINS AS A WEAK SHORTWAVE TROUGH CONTINUES TO PUSH
AWAY FROM THE FORECAST AREA. COMBINATION OF CLEARING SKY...VERY
LIGHT WINDS AND WIDESPREAD SNOW COVER WILL CONTRIBUTE TO VERY COLD
TEMPERATURES OVERNIGHT. AMBIENT TEMPERATURES WILL FALL BELOW ZERO
FOR ALL BUT THE FAR SOUTHEAST PORTION OF THE FORECAST AREA WHICH
WILL REMAIN AT OR SLIGHTLY ABOVE ZERO. DESPITE THE LIGHT
WINDS...WIND CHILL READINGS WILL FALL TO AS LOW AS 20 BELOW ZERO FOR
A PERIOD OF TIME PRIMARILY OVER THE NORTHWEST HALF OF THE FORECAST
AREA. AS SUCH...WILL ISSUE A WIND CHILL ADVISORY.
FOLTZ
TUESDAY-WEDNESDAY...SHORTWAVE RIDGING WILL BUILD OVER THE CWA
TUESDAY QUICKLY FOLLOWED BY WESTERLY FLOW ALOFT WEDNESDAY...WHICH
WILL FAVOR DRY CONDITIONS OVER CWA. SHALLOW COLD AIR MASS WILL BEGIN
TO MODERATE...WITH HIGH/LOW TEMP FORECAST COMPLICATED BY LINGERING
SNOW PACK. CONTINUED TO UNDERCUT GUIDANCE THROUGH THESE
PERIODS....NOT EXPECTING TEMPS TO MAKE IT ABOVE FREEZING UNTIL
WED AFTERNOON.
WEDNESDAY NIGHT-THURSDAY NIGHT...COLD FRONT PUSHES SOUTH ACROSS CWA
WEDNESDAY NIGHT...WITH SHORTWAVE TROUGH PASSING NORTH OF CWA
THURSDAY/THURSDAY NIGHT. BEST LIFT/MOISTURE LOOKS TO REMAIN OVER
CENTRAL NEBRASKA...HOWEVER MODEL POINT SOUNDINGS DO SHOW DENDRITIC
LAYER BEGINNING TO SATURATE IN EXTREME NORTHERN PART OF CWA IN THE
21Z-00Z TIME FRAME. WENT AHEAD AND ADDED SLIGHT CHANCE POPS TO SW
NEBRASKA COUNTIES 18Z-00Z WHERE A DUSTING COULDNT BE RULED OUT. ALSO
EXPANDED FLURRIES FURTHER SOUTH...AND MADE CONDITIONS DRY AFTER 06Z.
FRIDAY-MONDAY...WARMING TREND WILL START UP AGAIN FRIDAY...AND
CONTINUE THROUGH THE WEEKEND WITH SHORTWAVE RIDGING ACROSS WESTERN
CONUS THROUGH SATURDAY. TEMPERATURES SHOULD MODERATE TO NEAR
NORMAL VALUES IN THE UPPER 30S/LOW 40S SAT/SUN. CLOSED LOW BEGINS
TO DEVELOP OVER SW CONUS BY SUNDAY NIGHT/MONDAY WITH W/SW FLOW
DEVELOPING OVER CWA AHEAD OF THIS FEATURE. GUIDANCE IN GENERAL
AGREEMENT ON ARRIVAL OF COLD FRONT SUN NIGHT/MON...WHICH SHOULD
SUPPORT A RETURN TO BELOW NORMAL TEMPERATURES EARLY NEXT WEEK. NOT
EXPECTING ANY PRECIP THROUGH EXTENDED PERIODS...WITH DRY AIR MASS
IN PLACE OVER CWA.
DR
&&
.AVIATION...
1016 AM MST MON DEC 5 2011
FOR THE 18Z TAFS...MAIN CONCERN FOR THE PREVAILING PERIOD WILL BE
THE POSSIBILITY OF FOG/BR DEVELOPING OVERNIGHT AT BOTH TERMINALS.
TEMPERATURES WILL REMAIN COLD TODAY WHICH WILL LIMIT MELTING...
AND MAY AFFECT FOG FORMATION. HAVE DECIDED TO GO AHEAD AND INCLUDE
A PERIOD OF MVFR...WITH THE CHANCE OF REACHING IFR OR LIFR IF FOG
DEVELOPS. OTHERWISE...SURFACE HIGH PRESSURE ACROSS THE AREA WILL
KEEP WINDS LIGHT WITH CLEARING SKIES OVERNIGHT. A FEW FLURRIES AND
SOME SCATTER LOW LEVEL CLOUDS MAY BE POSSIBLE THIS AFTERNOON GIVEN
REGIONAL OBS...BUT IMPACTS WILL BE MINIMAL TO NONE.
PMM
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY FROM 11 PM MST /MIDNIGHT CST/ THIS EVENING
TO 8 AM MST /9 AM CST/ TUESDAY FOR KSZ001>003-013-014-027.
NE...WIND CHILL ADVISORY FROM 11 PM MST /MIDNIGHT CST/ THIS EVENING
TO 8 AM MST /9 AM CST/ TUESDAY FOR NEZ079>081.
CO...WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 8 AM MST TUESDAY
FOR COZ090>092.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
253 PM EST MON DEC 5 2011
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH NORTHERN MAINE THIS
EVENING AND THEN MOVE ACROSS THE STATE BY LATE TONIGHT. THE FRONT
WILL MOVE OFF THE COAST LATER TUESDAY WITH A SERIES OF WEAK LOW
PRESSURES TRACKING ALONG THE COASTAL FRONT TUESDAY NIGHT INTO
WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
FIRST SURGE OF RAIN HAS MOVED OUT OF NORTHERN MAINE EARLY THIS
AFTERNOON AS DEPICTED BY THE HRRR MODEL. THE HRRR MODEL DOES NOT
BRING THE NEXT SURGE BACK INTO NORTHERN MAINE UNTIL EARLY THIS
EVENING SO WILL START OUT WITH LOWER POPS ACROSS THE NORTH AND
THEN GRADUALLY INCREASE POPS BACK TO CATEGORICAL THIS EVENING. AS
THE COLD FRONT CROSSES NORTHERN MAINE AFTER MIDNIGHT, RAIN WILL
MIX WITH SNOW AND THEN CHANGE TO ALL SNOW ACROSS MAINLY NORTHERN
AROOSTOOK COUNTY. SNOW WILL CONTINUE INTO THE MORNING HOURS BUT
EXPECT SNOW TO BE LIGHT. AT THIS TIME STILL EXPECTING 1 TO 3
INCHES OF SNOW ACROSS NORTHERN SECTIONS WITH THE HIGHEST VALUES
ACROSS THE ST. JOHN VALLEY.
EXPECT RAIN TO MOVE INTO CENTRAL REGIONS AFTER MIDNIGHT AND THEN
INTO DOWNEAST JUST BEFORE SUNRISE TUESDAY. RAIN WILL CONTINUE FOR
MOST OF THE DAY OVER DOWNEAST AS LOW PRESSURE MOVES ALONG THE
FRONT AS IT SLIDES OFF THE COAST.
HIGH TEMPERATURES ON TUESDAY WILL ONLY RISE 1 TO 3 DEGREES FROM
THE MORNING LOWS AS COLDER AIR MOVES IN WITH THE NORTH WINDS
BEHIND THE COLD FRONT.
FOR RAINFALL AMOUNTS EXPECTING BETWEEN A QUARTER TO HALF AN INCH
ACROSS THE REGION BY TUESDAY AFTERNOON.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
THE UNSETTLED PATTERN WILL CONTINUE THROUGH THE SHORT TERM. A COLD
FRONT WILL BE STRETCHED ACROSS THE GULF OF MAINE TUESDAY NIGHT WITH
A WAVE OF LOW PRESSURE POSITIONED NEAR NOVA SCOTIA TUESDAY EVENING.
PRECIPITATION...MOSTLY IN THE FORM OF SNOW THOUGH MIXED WITH RAIN
DOWNEAST AND ESPECIALLY ALONG THE COAST... WILL BEGIN TO WIND DOWN
OVERNIGHT AS THIS LOW CONTINUES TO TREK TO THE EAST. HOWEVER ANOTHER
WEAK WAVE...THIS ONE FURTHER SOUTH...WILL KEEP AT LEAST THE SLIGHT
CHANCE OF RAIN/SNOW SHOWERS ACROSS THE REGION THROUGH WEDNESDAY
MORNING. HIGH PRESSURE WILL FINALLY BE ABLE TO TAKE HOLD WEDNESDAY
NIGHT...BUT YET ANOTHER LOW WILL MOVE TO THE SOUTH OF THE GULF OF
MAINE THURSDAY. THE 12Z ECMWF IS THE MOST AGGRESSIVE AND THE
FURTHEST NORTH WITH THIS SYSTEM AND INDICATES THAT MUCH OF DOWNEAST
MAINE WOULD SEE A RAIN/SNOW MIX. THE 12Z NAM AND GFS MEANWHILE KEEP
THE LOW SOUTH AND ONLY BRUSH THE COAST WITH PRECIPITATION. HAVE GONE
WITH SLIGHT CHANCE POPS FOR NOW. ALSO KEPT SLIGHT CHANCE POPS ACROSS
THE NORTH AS A COLD FRONT APPROACHES FROM CANADA. DAYTIME
TEMPERATURES WEDNESDAY AND THURSDAY WILL RANGE FROM THE LOWER 30S
NORTH TO AROUND 40 SOUTH WHILE THE NIGHTS DIP DOWN INTO THE 20S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE START OF THE LONG TERM FINDS THE GFS AND THE ECMWF WITH A
SIMILAR SOLUTION...HOWEVER THE GFS APPEARS ABOUT 6HRS BEHIND THE
ECMWF ON MOVEMENT OF THE MAIN LOW. A LOW PRESSURE (GFS) IN THE N
ATLANTIC SE OF NOVA SCOTIA...A DEEP COLD CORE LOW OVER HUDSON BAY
WITH A TROUGH EXTENDING S THROUGH THE CENTRAL GREAT LAKES REGION.
A CANADIAN HIGH PRESSURE RIDGE THAT DUG INTO THE SOUTHERN STATES
WILL BEGIN TO SPREAD TOWARDS NEW ENGLAND. THE ECMWF THE PRIMARY
LOW IS FARTHER NORTH INTO THE CANADIAN MARITIMES. AND THE BUILDING
RIDGE EXTEND FARTHER NORTH INTO SOUTHERN NEW ENGLAND. BY FRIDAY
MORNING THE HIGH MOVES INTO THE ATLANTIC... THE GFS DIGS THE
TROUGH ACROSS THE GREAT LAKE FARTHER SOUTH. THE ECMWF DEVELOPS A
WEAK LOW OVER EASTERN ILLINOIS. BY FRIDAY EVENING BOTH MODELS ARE
INDICATING A LOW OVER THE NORTHERN GREAT LAKES...WITH A TROUGH OF
LOWER PRESSURE EXTENDING SOUTH ALONG THE EASTERN SEABOARD. BY
EARLY SATURDAY MORNING BOTH MODELS MOVES THE LOW EAST...THE GFS TO
NRN MAINE...THE ECMWF TO SRN QUEBEC. BY SATURDAY MORNING THE GFS
MOVES THE LOW AND FRONT EAST OF THE AREA...THE ECMWF TO ERN MAINE.
BY SATURDAY EVENING THE LOW WILL BE WELL EAST AND A HIGH PRESSURE
RIDGE WILL BUILD IN. HIGHER PRESSURE WILL BUILD IN THROUGH THE END
OF THE PERIOD...HOWEVER THE COLD LOW OVER HUDSON BAY WILL REMAIN
THROUGH THE PERIOD AND WILL PERIODICALLY KICK OFF SHORT WAVES THAT
WILL MOVE THROUGH NORTHERN AND CENTRAL MAINE THROUGH THE END OF
THE PERIOD.
LOADED GMOS...WITH SOME HAND SMOOTHING. PLUS 15 PERCENT FOR GUST
OVER LAND 20 PERCENT OVER WATER. NAWAVE 4 FOR SEAS IN THE COASTAL
WATERS.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
NEAR TERM: VFR CONDITIONS ACROSS THE NORTH WILL LOWER TO MVFR THIS
EVENING AND THEN IFR BY LATER TONIGHT AND REMAIN IFR THROUGH
TUESDAY. VFR CONDITIONS ACROSS DOWNEAST WILL LOWER TO IFR AFTER
SUNRISE TUESDAY AND REMAIN IFR FOR THE REMAINDER OF THE DAY.
SHORT TERM: WIDESPREAD IFR IN SNOW /MIXED WITH RAIN SOUTH/
EXPECTED INTO WEDNESDAY MORNING...THEN GRADUALLY IMPROVING
CONDITIONS FROM NORTH TO SOUTH WEDNESDAY AFTERNOON AS HIGH
PRESSURE BUILDS OVER THE REGION. CLOUDS WILL INCREASE LATE
WEDNESDAY NIGHT AND THURSDAY AS A COLD FRONT APPROACHES FROM
CANADA AND A LOW PRESSURE SYSTEM MOVES TO THE SOUTH OF THE GULF OF
MAINE. THERE IS A SLIGHT CHANCE THAT THESE SYSTEMS WILL BRING SNOW
AND MVFR/IFR CONDITIONS TO THE REGION THURSDAY. MORE RAIN/SNOW IS
POSSIBLE FRIDAY AND FRIDAY NIGHT AS ANOTHER LOW MOVES ACROSS
NORTHERN MAINE.
&&
.MARINE...
NEAR TERM: WINDS AND SEAS WILL REMAIN BELOW SCA CRITERIA THROUGH
TUESDAY. A COLD FRONT WILL APPROACH FROM THE NORTH TONIGHT AND
TUESDAY AND THEN CROSS THE WATERS BY TUESDAY EVENING.
SHORT TERM: NO HEADLINES EXPECTED OVER THE WATERS AS WINDS REMAIN
BELOW 25 KT AND WAVES LESS THAN 5 FT. THE WEATHER WILL BE
UNSETTLED HOWEVER AS A SERIES OF LOW PRESSURE WAVES MOVE OVER OR
JUST TO THE SOUTH OF THE GULF OF MAINE THROUGH MID WEEK.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...FOSTER
SHORT TERM...HASTINGS
LONG TERM...NORTON
AVIATION...FOSTER
MARINE...FOSTER/HASTINGS
AREA FORECAST DISCUSSION...UPDATED FOR 00Z TAFS
NWS MARQUETTE MI
557 PM EST MON DEC 5 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY AND NRN ONTARIO THROUGH THE NRN PLAINS TO THE SRN
ROCKIES. LITTLE LOW OR MID LEVEL FORCING WAS ASSOCIATED WITH
THE TROUGH IN THE VERY DRY AIRMASS UPSTREAM. AT THE SFC...A RIDGE
EXTENDED FROM NRN ONTARIO INTO THE NRN PLAINS RESULTING IN WEAK NRLY
LOW LEVEL FLOW ACROSS LAKE SUPERIOR INTO UPPER MI. RADAR INDICATED
LIGHT DISORGANIZED LES INTO UPPER MI. ACYC FLOW INTO THE REGION AND
SHEAR WITHIN THE SFC-850 MB LAYER HAS LIMITED INTENSITY WITH
GENERALLY LIGHT ACCUMULATIONS OF AN INCH OR LESS OBSERVED IN WEST
AND NORTH CENTRAL UPPER MI. SNOW RATIO HAS BEEN HIGH...TYPICAL OF
MOST LES...WITH THE CLOUD LAYER IN THE 2K-6K FT DGZ.
&&
.SHORT TERM...TONIGHT AND TUESDAY
SOME INCREASE IN LES INTENSITY MAY BE POSSIBLE THIS EVENING AS THE
MID LEVEL TROUGH MOVES INTO THE AREA AND 850 MB TEMPS DROP SLIGHTLY
TO NEAR -15C. HOWEVER...THE CBL FLOW WILL ALSO BECOME INCREASINGLY
ANTICYCLONIC AS THE SFC RIDGE AXIS SHIFTS OVER THE AREA. THIS WILL
ALLOW THE WINDS TO BACK OVERNIGHT WHICH WILL SHIFT THE BEST SNOWFALL
BY MORNING TO THE ONTONAGON TO THE KEWEENAW AS WELL AS ALGER COUNTY.
DESPITE THE FAVORABLE INSTABILITY AND MOISTURE...THE SHEAR COMBINED
WITH THE SHIFTING NATURE OF THE BANDS SHOULD LIMIT SNOWFALL TO 1-2
INCHES...MAINLY FROM IWD-CMX AND FROM MQT-P53. THE LIGHT WINDS MAY
ALLOW THE DEVELOPMENT OF A BAND ALONG THE SHORELINE INTO THE WEST
ANE NEAR MARQUETTE AS THE LAND BREEZE STRENGTHENS...PER
HIGH RES WRF/ARW BUT CONFIDENCE IN DETAILS FOR LES BAND EVOLUTION
IN THE LIGHT WIND REGIME IS LOW. A BRIEF PERIOD OF HEAVIER SNOW
WOULD BE POSSIBLE IF SUCH A BAND DEVELOPS.
ANY LES ACROSS THE KEWEENAW AND EAST OF MARQUETTE SHOULD RAPIDLY
SHIFT OFFSHORE ON TUESDAY AS THE RIDGE AXIS MOVES SOUTHEAST.
CONDITIONS SHOULD BE MORE PLEASANT BY AFTERNOON WITH SOME SUNSHINE
OVER THE AREA ALONG WITH RELATIVELY LIGHT SW WINDS.
.LONG TERM /TUES NIGHT THROUGH NEXT MONDAY/...
AT THE START OF THE PERIOD...AN ELONGATED UPPER TROUGH WILL BE
STRETCHING FROM JAMES BAY TO THE SRN PLAINS AND QUICKLY SHIFTING E
OF THE AREA. THIS WILL ALLOW A WEAK RIDGE...AHEAD OF THE MAIN UPPER
LOW TO AFFECT THE AREA DURING THE LONG TERM OVER THE NW TERRITORIES
OF CANADA. THIS WEAK UPPER RIDGE WILL CAUSE SFC RIDGE TO SLIDE E
ACROSS THE CWA TUES EVENING.
MIGHT SEE A QUICK COOL DOWN TUES EVENING WITH THE CLEAR SKIES AND
LIGHT WINDS...ESPECIALLY OVER THE CNTRL/ERN CWA...BUT INCREASING
SWRLY FLOW AND MID LEVEL CLOUDS AHEAD OF THE NEXT FRONT WILL LEVEL
TEMPS OFF AND MAY EVEN CAUSE THEM TO RISE SOME OVER THE WRN CWA.
WITH THE DEEPER MOISTURE AND H850-700 Q-VECTOR CONV ARRIVING LATE
TUES NIGHT...COULD SEE A FEW SNOW SHOWERS LATE TUES NIGHT OVER THE
KEWEENAW. BUT WITH THE BEST FORCING/MOISTURE OVER NRN LK
SUPERIOR...WILL KEEP THE CHANCES THERE. STRONGER PRESSURE GRADIENT
AHEAD OF THE FRONT WILL LIKELY LEAD TO SOME GALES OVER LK SUPERIOR
TUES NIGHT. EVEN WITH THE WAA ALOFT...LLVL WINDS BELOW THE INVERSION
LOOK TO BE IN THE 30-40KT RANGE AND WILL LIKELY ALSO LEAD TO A GUSTY
OVERNIGHT FOR THE HIGHER TERRAIN OF KEWEENAW PENINSULA. WILL
CONTINUE THE GALE WATCH OVER W/CNTRL LK SUPERIOR.
COLD FRONT MOVING THROUGH ON WED AND WILL USHER IN THE COLDEST AIR
OF THE SEASON. EXPECT THE MID LVL FORCING/MOISTURE TO BE THROUGH THE
AREA BY WED AFTN...AND WILL MOVE UP THE POP TIMING FROM THE PREVIOUS
SHIFT TO BE MORE IN THE MORNING FROM THE AFTN. MAY TAKE A LITTLE
WHILE FOR THE LES TO GET GOING BEHIND THE FRONT...AS INVERSION
HEIGHTS FALL TO 4.5-5.5KFT AND LLVL DRY AIR LIMITS ANY POTENTIAL
CLOUD DEPTH. THUS...WILL GO WITH SLIGHTS OVER THE WNW WIND FAVORED
LOCATIONS OVER THE WEST AND KEEP CHANCES OVER THE EAST WHERE THE
LOW-MID LVL MOISTURE WILL TRY TO LINGER LONGER. THINK THESE LIMITED
CONDITIONS WILL CONTINUE INTO THE EVENING HOURS BEFORE REALLY
INTENSIFYING THROUGH THE NIGHT.
THIS INTENSIFICATION WILL LARGELY BE DUE TO A SHORTWAVE MOVING
THROUGH ON WED NIGHT...WHICH WILL INCREASE THE LOW-MID LVL MOISTURE
AND PULL EVEN COLDER H850 TEMPS OVER THE AREA /STEADILY FALLING TO
NEAR -20C BY THURS EVENING/. THIS WILL INCREASE DELTA-T/S TO SOME
FAIRLY IMPRESSIVE VALUES /LOW-MID 20S BY THURS EVENING/. IN
ADDITION...WITH INVERSION HEIGHTS RISING TO 7-10KFT AND LK INDUCED
CAPES IN THE 500-700 J/KG RANGE...LOOKS TO BE A GOOD POTENTIAL FOR
AREAS TO RECEIVE MOD/HEAVY LES LATE WED NIGHT INTO THURS. LAKE
EFFECT SNOW PARAMATER SUPPORTS THIS POTENTIAL...RISING ABOVE
2...WHICH SUPPORTS A HIGH POTENTIAL FOR HEAVY SNOWFALL RATES...OVER
THE W WED NIGHT AND THE E ON THURS. WINDS LOOK TO BE OUT OF THE WNW
WED NIGHT INTO THURS...SO HAVE THE HIGHEST POPS IN THOSE FAVORED
LOCATIONS. ONE ITEM TO NOTE ON WIND DIRECTIONS IS THAT THE NAM/GEM
HINTING AT A MESO LOW FORMING OVER ERN LK SUPERIOR ON THURS...WHICH
COULD END UP FORCING WINDS MORE TO THE NW OVER THE WRN CWA. OVER THE
E...THIS COULD CAUSE A DOMINATE BAND TO SETUP SOMEWHERE OVER THE
SERN LAKE...POTENTIALLY RIGHT ALONG THE SHORELINE E OF GRAND MARAIS
DUE TO THE WSW WINDS AROUND THE MESO LOW. FINALLY...COULD BE A
SLIGHT LULL OVER THE W IN THE AFTN...AS SLIGHTLY DRIER AIR MOVES
THROUGH...AND HAVE SLIGHTLY LOWERED POPS FOR THAT TIMEFRAME.
DAYS 4 THROUGH 7 /THURS NIGHT THROUGH NEXT MONDAY/...
ARCTIC TROUGH DROPPING SE ACROSS THE AREA THURS NIGHT INTO SAT WILL
PROVIDE REINFORCING COLD AIR TO THE AREA AND CONTINUE THE LES.
EXPECT THE -16 TO -20C H850 TEMPS TO CONTINUE THURS NIGHT INTO FRI
NIGHT AS BL WINDS ARE FROM THE WNW THURS NIGHT INTO FRI AND THEN
START TO SHIFT TO THE WSW FRI NIGHT. WITH THE ABUNDANT LOW-MID LVL
MOISTURE UNDER THE UPPER TROUGH...THE INGREDIENTS ARE COMING
TOGETHER FOR A POTENTIALLY SIGNIFICANT LES PERIOD THURS NIGHT INTO
FRI FOR WNW WIND FAVORED LOCATIONS. AS MENTIONED PREVIOUSLY...LES
PARAMETER CONTINUES TO HIGHLIGHT THE HEAVY SNOW POTENTIAL...VALUES
ABOVE 2...THROUGH FRI FOR WNW WIND LOCATIONS. THIS IS ALSO SEEN IN
BUFKIT LK INDUCED CAPE VALUES EXCEEDING 700 J/KG AND EQL LVLS
BETWEEN 7-10KFT. IT IS A WAYS OUT...BUT BUFKIT SOUNDINGS ARE SHOWING
THE CLOUD BASES TO BE AT OR ABOVE THE DGZ AND LIMIT DENDRITES.
EITHER WAY...SHOULD SEE A HIGH SLR VALUE AND ALLOW FOR EASY
BLOWING/DRIFTING FOR AREAS NEAR LK SUPERIOR WHERE THE WINDS WILL BE
STRONGEST. IN ADDITION...THIS DRIER AIR IN THE LLVLS COULD ALSO LEAD
TO A COUPLE MAIN/DOMINATE BANDS. WILL STICK TO OUR LES CLIMO POP/SKY
GRIDS FOR THIS TIME FRAME AND WILL CONTINUE TO MENTION THE HEAVY
SNOW POTENTIAL IN THE HWO. WITH THE WINDS SHIFTING TO THE SW AND WAA
DEVELOPING ON SAT...EXPECT THE LES TO DIMINISH. THIS WAA IS DUE TO A
WEAK SHORTWAVE AND CLIPPER SYSTEM SLIDES THROUGH SOUTHERN
ONTARIO...WITH THE MAIN ENERGY/MOISTURE STAYING N OF THE CWA.
UPPER FLOW TRANSITIONS TO MORE ZONAL NRN STREAM ALONG THE
U.S./CANADA BORDER FOR SUN INTO MON. THIS ALLOWS WARMER H850
TEMPS...AROUND -1 TO 1C...TO MOVE OVER THE AREA AND LEAD TO A PERIOD
OF SLIGHTLY ABOVE NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 20S
AND LOWER 30S. MODELS CONSISTENT ON SFC TROUGH SETTLING OVER THE
AREA SUN NIGHT INTO MON...AS SFC HIGHS ARE SETUP OVER THE NRN PLAINS
AND OHIO VALLEY. LIMITED UPPER LVL FORCING...SO HAVE KEPT THE FCST
DRY FOR NOW.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/
FOR THIS FCST PERIOD...WEATHER AT TAF SITES WILL BE DOMINATED BY
LAKE EFFECT CLOUDS/SNOW SHOWERS WITH PREDOMINANT MVFR CIGS.
AS IS TYPICAL FOR LAKE EFFECT SNOW SHOWERS...VSBY WILL BE QUITE
VARIABLE...GENERALLY RANGING FROM MVFR TONIGHT. SOME IMPROVEMENT IN
VIS IS EXPECTED TUE MORNIN AS WINDS BACK MORE WNW AHEAD OF BUILDING
HIGH PRES RDG DIMINISHING SHSN. VFR CONDITIONS WILL OCCUR IN THE
LATE MORNING TO EARLY AFTERNOON AT ALL SITES.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WINDS MOSTLY IN THE 10-20 KT RANGE INTO TUE MORNING AS A HIGH
PRES RIDGE OVER NORTHERN ONTARIO AND THE NRN PLAINS SLOWLY BUILDS
ACROSS LAKE SUPERIOR. AS THE RIDGE SLIPS SE OF THE LAKE AND A COLD
FRONT APPROACHES...SW WINDS ARE EXPECTED TO INCREASE TO GALE FORCE
TUE NIGHT INTO EARLY WED...MAINLY OVER WESTERN AND NCNTRL LAKE
SUPERIOR. A WINTRY PATTERN OF W-NW WINDS WILL THEN PERSIST THRU LATE
WEEK WITH LAKE EFFECT SNOW SHOWERS. GIVEN ARCTIC AIR PASSING OVER
THE LAKE...EFFICIENT MIXING WITH 20-30 KT AND SOME GALE FORCE GUSTS
AT TIMES LATE IN THE WEEK. WITH ARCTIC AIRMASS INTO THE AREA SOME
FREEZING SPRAY MAY ALSO DEVELOP.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING FOR
LSZ266.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ162.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EST MON DEC 5 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
HUDSON BAY AND NRN ONTARIO THROUGH THE NRN PLAINS TO THE SRN
ROCKIES. LITTLE LOW OR MID LEVEL FORCING WAS ASSOCIATED WITH
THE TROUGH IN THE VERY DRY AIRMASS UPSTREAM. AT THE SFC...A RIDGE
EXTENDED FROM NRN ONTARIO INTO THE NRN PLAINS RESULTING IN WEAK NRLY
LOW LEVEL FLOW ACROSS LAKE SUPERIOR INTO UPPER MI. RADAR INDICATED
LIGHT DISORGANIZED LES INTO UPPER MI. ACYC FLOW INTO THE REGION AND
SHEAR WITHIN THE SFC-850 MB LAYER HAS LIMITED INTENSITY WITH
GENERALLY LIGHT ACCUMULATIONS OF AN INCH OR LESS OBSERVED IN WEST
AND NORTH CENTRAL UPPER MI. SNOW RATIO HAS BEEN HIGH...TYPICAL OF
MOST LES...WITH THE CLOUD LAYER IN THE 2K-6K FT DGZ.
&&
.SHORT TERM...TONIGHT AND TUESDAY
SOME INCREASE IN LES INTENSITY MAY BE POSSIBLE THIS EVENING AS THE
MID LEVEL TROUGH MOVES INTO THE AREA AND 850 MB TEMPS DROP SLIGHTLY
TO NEAR -15C. HOWEVER...THE CBL FLOW WILL ALSO BECOME INCREASINGLY
ANTICYCLONIC AS THE SFC RIDGE AXIS SHIFTS OVER THE AREA. THIS WILL
ALLOW THE WINDS TO BACK OVERNIGHT WHICH WILL SHIFT THE BEST SNOWFALL
BY MORNING TO THE ONTONAGON TO THE KEWEENAW AS WELL AS ALGER COUNTY.
DESPITE THE FAVORABLE INSTABILITY AND MOISTURE...THE SHEAR COMBINED
WITH THE SHIFTING NATURE OF THE BANDS SHOULD LIMIT SNOWFALL TO 1-2
INCHES...MAINLY FROM IWD-CMX AND FROM MQT-P53. THE LIGHT WINDS MAY
ALLOW THE DEVELOPMENT OF A BAND ALONG THE SHORELINE INTO THE WEST
ANE NEAR MARQUETTE AS THE LAND BREEZE STRENGTHENS...PER
HIGH RES WRF/ARW BUT CONFIDENCE IN DETAILS FOR LES BAND EVOLUTION
IN THE LIGHT WIND REGIME IS LOW. A BRIEF PERIOD OF HEAVIER SNOW
WOULD BE POSSIBLE IF SUCH A BAND DEVELOPS.
ANY LES ACROSS THE KEWEENAW AND EAST OF MARQUETTE SHOULD RAPIDLY
SHIFT OFFSHORE ON TUESDAY AS THE RIDGE AXIS MOVES SOUTHEAST.
CONDITIONS SHOULD BE MORE PLEASANT BY AFTERNOON WITH SOME SUNSHINE
OVER THE AREA ALONG WITH RELATIVELY LIGHT SW WINDS.
.LONG TERM /TUES NIGHT THROUGH NEXT MONDAY/...
AT THE START OF THE PERIOD...AN ELONGATED UPPER TROUGH WILL BE
STRETCHING FROM JAMES BAY TO THE SRN PLAINS AND QUICKLY SHIFTING E
OF THE AREA. THIS WILL ALLOW A WEAK RIDGE...AHEAD OF THE MAIN UPPER
LOW TO AFFECT THE AREA DURING THE LONG TERM OVER THE NW TERRITORIES
OF CANADA. THIS WEAK UPPER RIDGE WILL CAUSE SFC RIDGE TO SLIDE E
ACROSS THE CWA TUES EVENING.
MIGHT SEE A QUICK COOL DOWN TUES EVENING WITH THE CLEAR SKIES AND
LIGHT WINDS...ESPECIALLY OVER THE CNTRL/ERN CWA...BUT INCREASING
SWRLY FLOW AND MID LEVEL CLOUDS AHEAD OF THE NEXT FRONT WILL LEVEL
TEMPS OFF AND MAY EVEN CAUSE THEM TO RISE SOME OVER THE WRN CWA.
WITH THE DEEPER MOISTURE AND H850-700 Q-VECTOR CONV ARRIVING LATE
TUES NIGHT...COULD SEE A FEW SNOW SHOWERS LATE TUES NIGHT OVER THE
KEWEENAW. BUT WITH THE BEST FORCING/MOISTURE OVER NRN LK
SUPERIOR...WILL KEEP THE CHANCES THERE. STRONGER PRESSURE GRADIENT
AHEAD OF THE FRONT WILL LIKELY LEAD TO SOME GALES OVER LK SUPERIOR
TUES NIGHT. EVEN WITH THE WAA ALOFT...LLVL WINDS BELOW THE INVERSION
LOOK TO BE IN THE 30-40KT RANGE AND WILL LIKELY ALSO LEAD TO A GUSTY
OVERNIGHT FOR THE HIGHER TERRAIN OF KEWEENAW PENINSULA. WILL
CONTINUE THE GALE WATCH OVER W/CNTRL LK SUPERIOR.
COLD FRONT MOVING THROUGH ON WED AND WILL USHER IN THE COLDEST AIR
OF THE SEASON. EXPECT THE MID LVL FORCING/MOISTURE TO BE THROUGH THE
AREA BY WED AFTN...AND WILL MOVE UP THE POP TIMING FROM THE PREVIOUS
SHIFT TO BE MORE IN THE MORNING FROM THE AFTN. MAY TAKE A LITTLE
WHILE FOR THE LES TO GET GOING BEHIND THE FRONT...AS INVERSION
HEIGHTS FALL TO 4.5-5.5KFT AND LLVL DRY AIR LIMITS ANY POTENTIAL
CLOUD DEPTH. THUS...WILL GO WITH SLIGHTS OVER THE WNW WIND FAVORED
LOCATIONS OVER THE WEST AND KEEP CHANCES OVER THE EAST WHERE THE
LOW-MID LVL MOISTURE WILL TRY TO LINGER LONGER. THINK THESE LIMITED
CONDITIONS WILL CONTINUE INTO THE EVENING HOURS BEFORE REALLY
INTENSIFYING THROUGH THE NIGHT.
THIS INTENSIFICATION WILL LARGELY BE DUE TO A SHORTWAVE MOVING
THROUGH ON WED NIGHT...WHICH WILL INCREASE THE LOW-MID LVL MOISTURE
AND PULL EVEN COLDER H850 TEMPS OVER THE AREA /STEADILY FALLING TO
NEAR -20C BY THURS EVENING/. THIS WILL INCREASE DELTA-T/S TO SOME
FAIRLY IMPRESSIVE VALUES /LOW-MID 20S BY THURS EVENING/. IN
ADDITION...WITH INVERSION HEIGHTS RISING TO 7-10KFT AND LK INDUCED
CAPES IN THE 500-700 J/KG RANGE...LOOKS TO BE A GOOD POTENTIAL FOR
AREAS TO RECEIVE MOD/HEAVY LES LATE WED NIGHT INTO THURS. LAKE
EFFECT SNOW PARAMATER SUPPORTS THIS POTENTIAL...RISING ABOVE
2...WHICH SUPPORTS A HIGH POTENTIAL FOR HEAVY SNOWFALL RATES...OVER
THE W WED NIGHT AND THE E ON THURS. WINDS LOOK TO BE OUT OF THE WNW
WED NIGHT INTO THURS...SO HAVE THE HIGHEST POPS IN THOSE FAVORED
LOCATIONS. ONE ITEM TO NOTE ON WIND DIRECTIONS IS THAT THE NAM/GEM
HINTING AT A MESO LOW FORMING OVER ERN LK SUPERIOR ON THURS...WHICH
COULD END UP FORCING WINDS MORE TO THE NW OVER THE WRN CWA. OVER THE
E...THIS COULD CAUSE A DOMINATE BAND TO SETUP SOMEWHERE OVER THE
SERN LAKE...POTENTIALLY RIGHT ALONG THE SHORELINE E OF GRAND MARAIS
DUE TO THE WSW WINDS AROUND THE MESO LOW. FINALLY...COULD BE A
SLIGHT LULL OVER THE W IN THE AFTN...AS SLIGHTLY DRIER AIR MOVES
THROUGH...AND HAVE SLIGHTLY LOWERED POPS FOR THAT TIMEFRAME.
DAYS 4 THROUGH 7 /THURS NIGHT THROUGH NEXT MONDAY/...
ARCTIC TROUGH DROPPING SE ACROSS THE AREA THURS NIGHT INTO SAT WILL
PROVIDE REINFORCING COLD AIR TO THE AREA AND CONTINUE THE LES.
EXPECT THE -16 TO -20C H850 TEMPS TO CONTINUE THURS NIGHT INTO FRI
NIGHT AS BL WINDS ARE FROM THE WNW THURS NIGHT INTO FRI AND THEN
START TO SHIFT TO THE WSW FRI NIGHT. WITH THE ABUNDANT LOW-MID LVL
MOISTURE UNDER THE UPPER TROUGH...THE INGREDIENTS ARE COMING
TOGETHER FOR A POTENTIALLY SIGNIFICANT LES PERIOD THURS NIGHT INTO
FRI FOR WNW WIND FAVORED LOCATIONS. AS MENTIONED PREVIOUSLY...LES
PARAMETER CONTINUES TO HIGHLIGHT THE HEAVY SNOW POTENTIAL...VALUES
ABOVE 2...THROUGH FRI FOR WNW WIND LOCATIONS. THIS IS ALSO SEEN IN
BUFKIT LK INDUCED CAPE VALUES EXCEEDING 700 J/KG AND EQL LVLS
BETWEEN 7-10KFT. IT IS A WAYS OUT...BUT BUFKIT SOUNDINGS ARE SHOWING
THE CLOUD BASES TO BE AT OR ABOVE THE DGZ AND LIMIT DENDRITES.
EITHER WAY...SHOULD SEE A HIGH SLR VALUE AND ALLOW FOR EASY
BLOWING/DRIFTING FOR AREAS NEAR LK SUPERIOR WHERE THE WINDS WILL BE
STRONGEST. IN ADDITION...THIS DRIER AIR IN THE LLVLS COULD ALSO LEAD
TO A COUPLE MAIN/DOMINATE BANDS. WILL STICK TO OUR LES CLIMO POP/SKY
GRIDS FOR THIS TIME FRAME AND WILL CONTINUE TO MENTION THE HEAVY
SNOW POTENTIAL IN THE HWO. WITH THE WINDS SHIFTING TO THE SW AND WAA
DEVELOPING ON SAT...EXPECT THE LES TO DIMINISH. THIS WAA IS DUE TO A
WEAK SHORTWAVE AND CLIPPER SYSTEM SLIDES THROUGH SOUTHERN
ONTARIO...WITH THE MAIN ENERGY/MOISTURE STAYING N OF THE CWA.
UPPER FLOW TRANSITIONS TO MORE ZONAL NRN STREAM ALONG THE
U.S./CANADA BORDER FOR SUN INTO MON. THIS ALLOWS WARMER H850
TEMPS...AROUND -1 TO 1C...TO MOVE OVER THE AREA AND LEAD TO A PERIOD
OF SLIGHTLY ABOVE NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 20S
AND LOWER 30S. MODELS CONSISTENT ON SFC TROUGH SETTLING OVER THE
AREA SUN NIGHT INTO MON...AS SFC HIGHS ARE SETUP OVER THE NRN PLAINS
AND OHIO VALLEY. LIMITED UPPER LVL FORCING...SO HAVE KEPT THE FCST
DRY FOR NOW.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/
FOR THIS FCST PERIOD...WEATHER AT TAF SITES WILL BE DOMINATED BY
LAKE EFFECT CLOUDS/SNOW SHOWERS WITH PREDOMINANT MVFR CIGS.
AS IS TYPICAL FOR LAKE EFFECT SNOW SHOWERS...VSBY WILL BE QUITE
VARIABLE...GENERALLY RANGING FROM MVFR TO IFR TODAY. SOME
IMPROVEMENT IN VIS IS EXPECTED EARLY TUE AS WINDS BACK MORE
WNW AHEAD OF BUILDING HIGH PRES RDG DIMINISHING SHSN...ESPECIALLY AT
KIWD AND KSAW.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WINDS MOSTLY IN THE 10-20 KT RANGE INTO TUE MORNING AS A HIGH
PRES RIDGE OVER NORTHERN ONTARIO AND THE NRN PLAINS SLOWLY BUILDS
ACROSS LAKE SUPERIOR. AS THE RIDGE SLIPS SE OF THE LAKE AND A COLD
FRONT APPROACHES...SW WINDS ARE EXPECTED TO INCREASE TO GALE FORCE TUE
NIGHT INTO EARLY WED...MAINLY OVER WESTERN AND NCNTRL LAKE SUPERIOR.
A WINTRY PATTERN OF W-NW WINDS WILL THEN PERSIST THRU LATE WEEK WITH
LAKE EFFECT SNOW SHOWERS. GIVEN ARCTIC AIR PASSING OVER THE
LAKE...EFFICIENT MIXING WITH 20-30 KT AND SOME GALE FORCE GUSTS
AT TIMES LATE IN THE WEEK. WITH ARCTIC AIRMASS INTO THE AREA SOME
FREEZING SPRAY MAY ALSO DEVELOP.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING FOR
LSZ266.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ162.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
115 PM EST MON DEC 5 2011
UPDATED FOR 18Z AVIATION DISCUSSION
.DISCUSSION...
RECENT RADAR IMAGES ARE STARTING TO SHOW SOME ORGANIZATION TO THE
LES...ESPECIALLY JUST OFFSHORE OF MARQUETTE COUNTY AS WELL AS A
CONVERGENCE BAND JUST OFFSHORE NEAR SAXON HARBOR. WITH GENERAL LIGHT
WINDS ACROSS THE INLAND AREAS...STRONG LAND BREEZES HAVE DEVELOPED
THAT HAS HELPED THESE BANDS TO FORM. THE MAIN PROBLEM IS THAT LES
POTENTIAL IS STILL VERY UNCLEAR TODAY. IN A GENERAL SENSE...THE LES
IS HAVING A HARD TIME DEVELOPING THIS MORNING DESPITE 850MB TEMPS
AROUND -12C AND CONVERGENT NORTHERLY FLOW. 00Z SOUNDINGS FROM INL
AND YPL MAY SUGGEST WHY LES IS STRUGGLING WITH LOW INVERSION HEIGHTS
UNDER 4000 FT AND VERY DRY AIR ALOFT. MQT VWP SUGGESTS THAT THE
INVERSION IS HIGHER DOWNWIND OF LAKE SUPERIOR...BUT THE DRY AIR
ALOFT REMAINS A PROBLEM AS DOES THE SHEAR AT THE TOP OF THE
INVERSION. WITH THAT BEING SAID...THE RUC AND RAPID REFRESH SEEM TO
HAVE A GOOD HANDLE ON THE LES INITIATION ON THE LAND BREEZE
BOUNDARIES...AND EVEN THE 06Z NAM SUGGESTS SOME BETTER BANDS NEAR
IWD ASSOCIATED WITH THE LAND BREEZE. WILL REALLY NEED TO MONITOR THE
BAND JUST NORTH OF IWD THIS MORNING. AS THE LAND BREEZE BREAKS DOWN
THIS MORNING...THE BAND WILL LIKELY MOVE INLAND AS THE PRIMARY
SYNOPTIC FLOW REMAINS NORTHERLY THROUGH THE DAY. WITH THE COLDER
850MB TEMPS OVER THE WESTERN U.P. THIS MORNING...THE SNOW GROWTH
REGION WILL BE IN CONVECTIVE BOUNDARY LAYER WHICH SHOULD HELP SNOW
RATIOS RISE TO 20-25:1 TODAY. THIS WOULD SUGGEST THAT IT WOULD NOT
TAKE MUCH FOR ADVISORY LEVEL SNOW TO BE REACHED TODAY AROUND IWD
TODAY...ESPECIALLY SINCE DEEPER MOISTURE ARRIVES THIS AFTERNOON AS
THE WAVE CURRENTLY OVER MN MOVES ACROSS LAKE SUPERIOR. THIS SHOULD
HELP TO INCREASE LES COVERAGE AND INTENSITY ACROSS THE WEST LATER
THIS AFTERNOON AND ACROSS THE CENTRAL AND EASTERN FORECAST SNOWBELTS
TONIGHT. LAKE INDUCED INSTABILITY WILL ALSO BE HIGHER OVERNIGHT WITH
850MB TEMPS DROPPING TO -16C. HOWEVER...THE PBL FLOW WILL ALSO
BECOME INCREASINGLY ANTICYCLONIC AS THE NIGHT GOES ON AS THE SFC
RIDGE AXIS SHIFTS OVER THE AREA. THIS WILL ALLOW THE WINDS TO BACK
OVERNIGHT WHICH WILL SHIFT THE BEST SNOWFALL BY MORNING TO THE
ONTONAGON TO THE KEWEENAW AS WELL AS ALGER COUNTY. DESPITE THE
FAVORABLE INSTABILITY AND MOISTURE...THE SHEAR IN PBL COMBINED WITH
THE SHIFTING NATURE OF THE BANDS SHOULD LIMIT SNOWFALL TO 1-3
INCHES...MAINLY FROM IWD-CMX AND FROM MQT-P53.
ANY LES ACROSS THE KEWEENAW AND EAST OF MARQUETTE SHOULD RAPIDLY
SHIFT OFFSHORE ON TUESDAY AS THE RIDGE AXIS MOVES SOUTHEAST. WILL
END UP BEING A DECENT AFTERNOON ON TUESDAY WITH SOME SUNSHINE NOT
OUT OF THE QUESTION. CLEAR SKIES SHOULD ALLOW TEMPS TO DROP INTO THE
SINGLE DIGITS BY WED MORNING ACROSS MANY INTERIOR LOCATIONS. THE
NEXT FRONT WILL PASS THROUGH THE AREA WEDNESDAY. THIS FRONT WILL
USHER IN THE COLDEST AIR OF THE SEASON SO FAR. IT STILL LOOKS LIKE A
RATHER SNOWY PERIOD FOR AREAS FAVORED IN W-NW FLOW SUCH AS THE
KEWEENAW PENINUSLA AND AREAS EAST OF MUNISING. IN ADDITION TO THE
PURE LAKE EFFECT...THERE WILL BE SEVERAL OPPORTUNITIES FOR LAKE
ENHANCEMENT AS UPPER DISTURBANCES ROTATE AROUND THE HUDSON BAY LOW.
ALTHOUGH IT IS TOO EARLY FOR ANY WATCHES...PEOPLE IN THE KEWEENAW
AND AREAS EAST OF MUNISING SHOULD SEE SIGNIFICANT SNOW ACCUMULATIONS
FROM WED NIGHT THROUGH FRIDAY (AND PERHAPS EVEN INTO SATURDAY). THE
GFS SOUNDINGS SHOW INVERSION HEIGHTS AROUND 8000 FT WITH LAKE
INDUCED CAPE VALUES AT LEAST 800 J/KG BY THU. ONLY CONCERN FOR A
MAJOR LAKE EFFECT SNOW EVENT IS THE DRY BOUNDARY LAYER WHICH WILL
UNDOUBTEDLY ACCOMPANY THE ARCTIC AIRMASS. FOR NOW...WILL CONTINUE TO
MENTION THE POSSIBILITY FOR HEAVY LES IN THE HAZARDOUS WEATHER
OUTLOOK.
OTHERWISE...THE WEATHER FOR AREAS AWAY FROM LES SHOULD BE FAIRLY
QUIET THROUGH MUCH OF THE WEEK. IT WILL BE MUCH COLDER THAN NORMAL
FOR THU-SAT WITH TEMPS STRUGGLING TO RISE INTO THE 20S. BY
SUNDAY...HEIGHT RISES WILL ALLOW FOR THE LES TO END AND TEMPS TO
RISE BACK TO NEAR NORMAL AS THE FLOW TURNS SWLY.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/
FOR THIS FCST PERIOD...WEATHER AT TAF SITES WILL BE DOMINATED BY
LAKE EFFECT CLOUDS/SNOW SHOWERS WITH PREDOMINANT MVFR CIGS.
AS IS TYPICAL FOR LAKE EFFECT SNOW SHOWERS...VSBY WILL BE QUITE
VARIABLE...GENERALLY RANGING FROM MVFR TO IFR TODAY. SOME
IMPROVEMENT IN VIS IS EXPECTED EARLY TUE AS WINDS BACK MORE
WNW AHEAD OF BUILDING HIGH PRES RDG DIMINISHING SHSN...ESPECIALLY AT
KIWD AND KSAW.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WINDS MOSTLY IN THE 10-20 KT RANGE THROUGH TUE AS A HIGH PRES
RIDGE OVER NORTHERN ONTARIO AND THE NRN PLAINS SLOWLY BUILDS ACROSS
LAKE SUPERIOR. AS THE RIDGE SLIPS SE OF THE LAKE AND A COLD
FRONT APPROACHES...SW WINDS WILL LIKELY INCREASE TO GALE FORCE TUE
NIGHT INTO EARLY WED...MAINLY OVER WESTERN AND NCNTRL LAKE SUPERIOR.
A WINTRY PATTERN OF W-NW WINDS WILL THEN PERSIST THRU LATE WEEK WITH
LAKE EFFECT SNOW SHOWERS. GIVEN ARCTIC AIR PASSING OVER THE
LAKE...EFFICIENT MIXING MAY RESULT IN BRIEF GALES AT TIMES LATE IN
THE WEEK. MAY NEED TO CONSIDER THE POTENTIAL OF FREEZING SPRAY AS
WELL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING FOR
LSZ266.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ162.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
DISCUSSION...MRD
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
334 PM CST MON DEC 5 2011
.SHORT TERM...
THE MAIN FOCUS FOR THE SHORT TERM WILL CONTINUE TO BE THE WINTER
WEATHER IMPACTS ASSOCIATED WITH A STRONG UPPER-LOW PRESSURE SYSTEM
STILL PUSHING THROUGH THE FOUR CORNERS REGION. OVER THE COURSE OF
THE DAY...LIGHT SNOW SHOWERS HAVE PERSISTED ACROSS THE
CAPROCK...THOUGH VERY MINOR ACCUMULATIONS HAVE OCCURRED SINCE THE
MID-MORNING HOURS. HOWEVER...CURRENT OBS...SATELLITE AND RADAR
IMAGERY AND MODEL PROJECTIONS ARE SHOWING THE POTENTIAL FOR SOME
ADDITIONAL AREAS OF LIGHT SNOWFALL TO MOVE INTO THE AREA LATE THIS
AFTERNOON AND THIS EVENING AS ANOTHER LOBE OF ENERGY FROM THE
AFOREMENTIONED UPPER-LOW ROTATES OVER THE REGION. MOST OF THE QPF
SIGNALS SHOWN ARE FAIRLY LIGHT...BUT THE TTU WRF AND THE HRRR BOTH
SHOW SOME ENHANCED PRECIPITATION BANDS DEVELOPING ACROSS THE
NORTHWESTERN ZONES THIS EVENING. THIS THINKING SEEMS TO BE PLAUSIBLE
AS IR SATELLITE DATA IS INDICATING A BAND OF COLDER CLOUD TOPS
PUSHING INTO THE WESTERN PANHANDLE...WITH SURFACE OBS AT CLOVIS
DROPPING DOWN TO 1-2 SM DUE TO SNOW. THUS...SOME LOCALIZED BURSTS OF
MODERATE SNOW WILL BE POSSIBLE /PARTICULARLY ACROSS THE SW
PANHANDLE/ WHERE AN ADDITIONAL INCH OF SNOW MAY BE POSSIBLE TONIGHT.
HAVE INCREASED POPS TO LIKELY TO CHANCE ACROSS MUCH OF THE AREA THIS
EVENING...BEFORE LOWERING THEM AFTER MIDNIGHT AS PRECIPITATION
BEGINS TO WANE.
THE OTHER BIG CONCERN FOR THIS EVENING WILL BE THE BRISK NORTHERLY
WINDS AND STRONG COLD AIR ADVECTION OCCURRING...WHICH WILL DROP
TEMPERATURES INTO THE SINGLE DIGITS ACROSS THE SW PANHANDLE AND INTO
THE TEENS ACROSS THE REST OF THE AREA. GIVEN THE BITTERLY COLD
TEMPERATURES AND WINDS THAT SHOULD REMAIN ABOVE 10 MPH OVERNIGHT
SOME LOW WIND CHILLS WILL DEVELOP AFTER SUNSET. GIVEN THE POTENTIAL
FOR SOME DANGEROUSLY COLD WINDS CHILLS AT OR AROUND -5 DEGREES
OCCURRING LATER TONIGHT ACROSS THE NORTHWEST ZONES...HAVE PLACED
THAT AREA IN A WIND CHILL ADVISORY THROUGH 15Z TOMORROW. GIVEN THE
POTENTIAL FOR SOME ADDITIONAL /ALBEIT GENERALLY LIGHT/ SNOWFALL
ACCUMULATIONS ON THE CAPROCK THIS EVENING AND ALREADY HAZARDOUS
DRIVING CONDITIONS FROM BLACK ICE AND SNOW ON AREA ROADWAYS...HAVE
OPTED TO EXTEND THE WINTER WEATHER ADVISORY ON THE CAPROCK UNTIL
12Z. TOMORROW WILL BE A BITTERLY COLD DAY ACROSS THE AREA...AS HIGHS
WILL GENERALLY REMAIN WELL BELOW FREEZING IN THE 20S DUE TO VERY LOW
THICKNESS VALUES AND A CONTINUED NORTHERLY WIND.
&&
.LONG TERM...
AMPLIFIED PATTERN THROUGHOUT THE CONUS WILL SLOWLY RELAX BY MIDWEEK
RESULTING IN BRIEFLY ZONAL FLOW AND SLIGHTLY MILDER TEMPS ON THE
SOUTH PLAINS. THIS PATTERN HOWEVER STILL LOOKS TO BREAK DOWN ON
FRIDAY YIELDING BROADLY CYCLONIC FLOW COURTESY OF A DEEP POLAR
VORTEX TAKING RESIDENCE IN THE HUDSON BAY. JUST A GLANCING BLOW
FROM THIS BROAD TROUGH WILL YIELD A DRY POLAR FRONT LATE THU
NIGHT/EARLY FRI SERVING TO KNOCK HIGHS ON FRI 15-20 DEG BELOW CLIMO.
MEDIUM RANGE MODELS INSIST ON DEEPER WEST OR SWLY FLOW BY THE
WEEKEND INDICATIVE OF MORE SEASONABLE TEMPS.
GREATEST FORECAST CHALLENGE THIS PERIOD INVOLVES LO TEMPS TUE NIGHT
AS STRATUS CLEARS AND WINDS SLACKEN WITHIN AN ELONGATED SURFACE
RIDGE. CHOSE NOT TO LOWER INHERITED MIN TEMPS MUCH BELOW GUIDANCE
FOR NOW AS ALL NUMERICAL DATA INDICATE LIGHT WESTERLY FLOW
OVERNIGHT. SHOULD THESE LIGHT WINDS VEER MORE NLY IN LATER
FORECASTS...THEN THE RECORD DAILY LOW AT LBB /8 SET IN 2005/ MAY
BE IN JEOPARDY.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 8 21 7 40 17 / 60 10 0 0 0
TULIA 12 22 11 41 18 / 50 10 0 0 0
PLAINVIEW 13 23 10 40 18 / 50 10 0 0 0
LEVELLAND 13 22 9 40 19 / 50 10 0 0 0
LUBBOCK 15 25 11 40 19 / 40 10 0 0 0
DENVER CITY 14 26 16 40 20 / 50 10 0 0 0
BROWNFIELD 14 26 13 40 20 / 50 10 0 0 0
CHILDRESS 20 30 17 42 21 / 20 10 0 0 0
SPUR 20 30 15 44 20 / 30 10 0 0 0
ASPERMONT 21 33 20 45 22 / 20 10 10 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR THE FOLLOWING
ZONES: TXZ021>024-027>030-033>036-039>042.
WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST TUESDAY
FOR THE FOLLOWING ZONES: TXZ021>023-027-028.
&&
$$
22/93
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
245 PM CST MON DEC 5 2011
.SHORT TERM...
245 PM CST MON DEC 5 2011
BIGGEST FORECAST CONCERN IS ON CLOUDS AND TEMPERATURES...WITH LIGHT
PRECIPITATION CHANCES THIS EVENING ALSO A CONCERN.
18Z WATER VAPOR IMAGERY SHOWS SHORTWAVE TROUGH OVER
MINNESOTA...WHILE AT THE SURFACE A WEAK TROUGH WAS WORKING ITS WAY
THROUGH THE FORECAST AREA...BUT WAS WEAKENING WITH TIME. THIS
COMBINATION WAS PRODUCING WEAK LIFT THROUGH SATURATED LOWER LAYER
AND THUS SURFACE REPORTS INDICATING MAINLY LIGHT SNOW AND
FLURRIES...WITH SOME PATCHY FREEZING DRIZZLE.
05.12Z MODELS AGAIN IN GOOD AGREEMENT WITH THEIR MASS FIELDS. THERE
IS SOME DIFFERENCES IN SPEED OF COLDER PLUNGE OF AIR ON
THURSDAY...WITH THE NAM THE FASTEST. ONLY OTHER DIFFERENCE NOTED IS
GFS A LITTLE FASTER IN PUSHING THE STRATUS OUT ON TUESDAY.
FOR TONIGHT...SHORTWAVE IN MINNESOTA ROTATES INTO NORTHWEST
WISCONSIN. MODEL SOUNDINGS INDICATE WEAK LIFT CONTINUES IN THE
SATURATED LOWER LAYER DURING THE EVENING. 05.15Z RUC SOUNDINGS
QUESTIONABLE WITH REGARDS TO ICE IN THE CLOUD LAYER...WHILE NAM
SOUNDINGS SUGGEST MORE ICE. BASED ON REPORTS FROM THIS AFTERNOON
MENTION FLURRIES AND PATCHY FREEZING DRIZZLE FOR THE EVENING HOURS.
WITH THE CLOUDS DID GO ON THE WARMER SIDE OF THE GUIDANCE NUMBERS
FOR LOWS TONIGHT.
ON TUESDAY...GFS A LITTLE FASTER IN PUSHING THE STRATUS OUT OF THE
AREA...WHILE THE NAM KEEPS 850MB-925MB MOISTURE OVER THE AREA
THROUGHOUT THE DAY AND NOT CLEARING UNTIL EVENING. DID TAKE A
COMPROMISE...WITH A CLEARING TREND FROM WEST TO EAST DURING THE
AFTERNOON HOURS. TEMPERATURES WILL BE TRICKY WITH THE CLOUDS...BUT
WITH THE MORE PESSIMISTIC OUTLOOK DID GO WITH THE COOLER OF THE
GUIDANCE NUMBERS.
DO EXPECT CLEAR SKIES...AT LEAST FOR A SHORT PERIOD OF TIME TUESDAY
NIGHT. HOWEVER...ANOTHER SHORTWAVE BEGINS TO DROP SOUTHWARD OUT OF
SOUTHERN CANADA LATE TUESDAY NIGHT...AND MODELS HINT AT AN INCREASE
IN HIGH LEVEL CLOUDS. THESE CLOUDS THEN DROP ACROSS THE AREA ON
WEDNESDAY AND WEDNESDAY NIGHT AHEAD OF THE ASSOCIATED COLD FRONT.
TEMPERATURES LOOK TO BE A LITTLE MILDER AHEAD OF THE FRONT...BUT
STILL BELOW NORMAL WITH HIGHS FROM THE MIDDLE 20S IN THE SNOW
COVERED LOCATIONS...TO THE LOWER 30S IN THE NON SNOW COVERED AREAS.
ON THURSDAY COLD AIR BEGINS TO SURGE INTO THE AREA BEHIND THE FRONT.
AS MENTIONED BEFORE NAM QUICKER IN MOVING THIS COLD AIR INTO THE
REGION AND AGAIN USED A MODEL CONSENSUS FOR HIGHS. 05.12 GFS AND
ECMWF ALSO GENERATING SOME LIGHT PRECIPITATION ALONG THE LEADING EDGE
OF THE COLD AIR ACROSS IOWA IN BAND OF WEAK FRONTOGENESIS. WITH THE
BULK OF PUSH OF COLD AIR THURSDAY NIGHT...DID ADD SOME LOWER END
SNOW PROBABILITIES ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
.LONG TERM...
245 PM CST MON DEC 5 2011
A DRY NORTHWEST LOW PATTERN WILL CONTINUE FOR FRIDAY AND SATURDAY
AND THIS WILL LEAD TO BELOW NORMAL TEMPERATURES. THE FLOW WILL BECOME
MORE ZONAL ON SUNDAY AS A TROUGH BUILDS INTO THE WESTERN CONUS. AS
THE TROUGH PROGRESSES INTO THE CENTRAL SECTIONS OF THE COUNTRY...THE
FLOW WILL BECOME MORE SOUTHWESTERLY. DRY CONDITIONS WILL CONTINUE
THROUGH MONDAY...BUT WITH A MORE SOUTHERLY WIND...TEMPERATURES WILL
WARM SATURDAY AND SUNDAY...WITH HIGHS EXPECTED IN THE 30S BOTH SUNDAY
AND MONDAY.
&&
.AVIATION...TODAY THROUGH TUESDAY
1135 AM CST MON DEC 5 2011
SHORT WAVE TROUGH MOVING INTO MINNESOTA SHOULD KEEP CLOUDS IN MOST
AREAS BUT BEEN BATTLING SOME BREAKS THIS MORNING. EXPECT THAT TO BE
SHORT LIVED...NEXT FEW HOURS...AND THEN AT LEAST MVFR CEILINGS
MOVING BACK IN.
ENOUGH GENERAL LIFT FOR PRECIPITATION AS WELL...ALBEIT MAINLY NORTH
OF INTERSTATE 90. MODEL SOUNDINGS SUGGEST TOP OF CLOUD LAYER MAY BE
JUST COLD ENOUGH TO INTRODUCE ICE INTO COLUMN BUT VERY MARGINAL.
WILL BANK ON BULK OF PRECIPITATION REMAINING SNOW BUT COULD NOT RULE
OUT BRIEF PATCHY FREEZING DRIZZLE. VISIBILITIES WITH SNOW FALLING
HAVE REMAINED MAINLY MVFR AND NO BIG CHANGE EXPECTED BEFORE
PRECIPITATION ENDS THIS EVENING.
MODELS HAVE ALSO BEEN SLOWING IDEA OF DRIER LOW LEVEL AIR COMING IN
BEHIND THIS SHORT WAVE TROUGH SO CLOUDS EXPECTED TO REMAIN TOUGH
WELL INTO TUESDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
245 PM CST MON DEC 5 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION.....SHEA/ZT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
203 PM CST MON DEC 5 2011
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE STATE OF
WISCONSIN LOCATED BETWEEN A COLD FRONT RUNNING UP THE EASTERN SIDE
OF THE APPALACHIANS...AND A POLAR SURFACE HIGH STRETCHING ACROSS THE
DAKOTAS EARLY THIS AFTERNOON. A WEAK SURFACE TROUGH REMAINS A
NUISANCE WHICH HANGS BACK FROM JUST SOUTH OF MILWAUKEE TO EAU
CLAIRE. RADAR RETURNS HAVE GRADUALLY ERODED OVER CENTRAL AND
EAST-CENTRAL WISCONSIN OVER THE COURSE OF THE DAY...THOUGH BEEFIER
RETURNS AND SURFACE OBS SHOW LIGHT SNOW SHOWERS OCCURRING OVER
WESTERN WISCONSIN. SOME HOLES IN THE CLOUDS ARE TRYING TO DEVELOP
OVER NORTHEAST WISCONSIN...AND PERHAPS INTO CENTRAL WISCONSIN AS
WELL. AS THE SURFACE HIGH SHIFTS EAST TONIGHT...CLOUD TRENDS AND
TEMPS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...HIGH PRESSURE OVER THE NORTHERN PLAINS WILL BUILD EAST
OVER THE NORTHERN MISSISSIPPI VALLEY. HOWEVER...FLOW WILL CONTINUE
TO BE OUT OF THE NORTH AND LIGHTLY ADVECTING CLOUDS OFF LAKE
SUPERIOR. IN ADDITION...12Z GUIDANCE SUPPORTS LINGERING LOW LEVEL
CONVERGENCE OVER CENTRAL WISCONSIN THAT WILL KEEP AN AREA OF
ENHANCED RH IN PLACE. KEPT A FLURRY MENTION OVER THE FAR WESTERN
CWA TO ACCOUNT FOR THIS. WITH PLENTY OF CLOUDS UPSTREAM...HAVE A
HARD TIME GOING BELOW MOSTLY CLOUDY CONDITIONS. THERE WILL BE
UNDOUBTEDLY SUCKER HOLES THAT WILL DEVELOP WITHIN THE
STRATUS...MOSTLY LIKELY WITHIN THE DOWNSLOPING AREAS OF NORTHEAST
WISCONSIN. WILL PLAY THE PROBABILITY THAT SCT CONDITIONS DEVELOP
THERE...BUT LEAVE MOSTLY CLOUDY CONDITIONS ELSEWHERE...WITH SCT SNOW
SHOWERS OVER THE SNOW BELT OF N-C WISCONSIN. LOWS IN THE LOWER
TEENS NORTH TO MIDDLE 20S SOUTHEAST. TEMPS COULD BE MUCH COLDER
OVER THE SNOW PACK OF N-C WISCONSIN IF HOLES IN THE CLOUDS DO
DEVELOP THERE.
TUESDAY...HIGH PRESSURE BUILDS INTO THE REGION TOMORROW. ANY
SURFACE CONVERGENCE ALONG THE LINGERING TROUGH OVER CENTRAL
WISCONSIN IS PROGGED TO DISSIPATE IN THE MORNING...BUT MODELS
INDICATE THE REMNANTS OF THE ENHANCED RH MOVING EAST AS LIGHT SW
FLOW DEVELOPS. ALSO SEE SIGNS OF STEEP LOW LEVEL LAPSE RATES WITH
HEATING OF THE DAY THAT POINTS TOWARDS STRATO-CU DEVELOPING. WITH
CLOUDS UNDER THE HIGH CURRENTLY...WILL SIDE MORE PESSIMISTICALLY
WITH CLOUD COVER...WHICH WILL KEEP MOSTLY CLOUDY CONDITIONS OVER
NORTH-CENTRAL WISCONSIN FOR THE MORNING...AND PARTLY CLOUDY
CONDITIONS EVERYWHERE FOR THE AFTERNOON. HIGHS RANGING FROM THE
LOWER 20S NORTH TO AROUND 30 DEGREES SOUTHEAST.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...THE MAIN FCST
CONCERN IS THE ARRIVAL OF ARCTIC AIR LATER IN THE WEEK.
SHORT-WAVE ENERGY CURRENTLY OVER THE GULF OF ALASKA WILL TOP THE
WEST COAST RIDGE...THEN HELP TO CARVE A BROAD TROF OVER THE
CENTRAL U.S. BY THURSDAY. A SURGE OF ARCTIC AIR IS EXPECTED TO
ARRIVE IN WI ON THURSDAY...WITH H8 TEMPS PLUMMETING TO -16 TO
-20 C BY FRIDAY. THIS WILL LEAD TO OUR COLDEST TEMPERATURES SO
FAR THIS SEASON. THE COLDER WEATHER WILL NOT LAST LONG...AS
SOUTHWEST WINDS DEVELOP IN THE WAKE OF THE RETREATING ARCTIC
HIGH OVER THE WEEKEND. H8 TEMPS ARE EXPECTED TO SURGE TO 0 TO
+4 C BY SATURDAY NIGHT/SUNDAY.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING ON THURSDAY.
HAVE BEEN WATCHING FOR POSSIBLE SNOW DEVELOPMENT AS THE RRQ OF A
STG UPPER JET INTERACTS WITH THE ARCTIC FRONT THURSDAY NIGHT
INTO FRIDAY...BUT THE CONCENSUS OF THE MODELS...INCLUDING THE
12Z/MON ECMWF...IS THAT SNOW WILL DEVELOP TO OUR SOUTH AND EAST.
WILL NOT CARRY ANY POPS AT THIS TIME...BUT SUBSEQUENT SHIFTS WILL
STILL NEED TO KEEP AN EYE ON THIS.
DESPITE THE PRESENCE OF A COLD AIR MASS FROM WEDNESDAY THROUGH
FRIDAY NIGHT...WIND TRAJECTORIES WILL BE TOO WESTERLY FOR ANY
APPRECIABLE LK-EFFECT SNOW.
MODELS HAVE BACKED OFF SLIGHTLY ON THE MAGNITUDE OF THE COLD SNAP
LATE IN THE WORK WEEK...WITH H8 TEMPS TRENDING A FEW DEGREES
WARMER. EVEN SO...STILL EXPECT MAX TEMPS TO BE ABOUT 10 DEGREES
BLO NORMAL ON FRIDAY. THE COLDER WEATHER WILL BE SHORT-LIVED...
WITH ABOVE NORMAL TEMPERATURES QUICKLY RETURNING BY SUNDAY.
A WEAK COLD FRONT MAY IMPACT THE REGION ON MONDAY...BUT SHOULD
NOT HAVE ANY SIGNIFICANT IMPACT ON OUR WEATHER.
&&
.AVIATION...CLOUDY OR MOSTLY CLOUDY VFR CONDITIONS WILL PREVAIL
ACROSS THE TAF SITES THROUGH THE PERIOD. SOME HOLES IN THE STRATUS
WILL LIKELY DEVELOP...BUT TRYING TO PREDICT WHERE IS DIFFICULT. THE
MOST LIKELY AREAS WILL BE OVER THE FOX VALLEY WHERE A SMALL
DOWNSLOPING COMPONENT WILL EXIST. SOME POSSIBILITY OF LOWERING CIGS
OVER NORTH-CENTRAL WISCONSIN LATE TONIGHT INTO TOMORROW MORNING
WHERE MODELS PROJECT STEEP LOW LEVEL LAPSE RATES DEVELOPING. WILL
REMAIN OPTIMISTIC GIVEN SOME LOW END VFR CIGS UPSTREAM.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TSK
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1252 PM CST MON DEC 5 2011
.UPDATE...
CONVERGING WINDS ALONG THE LONG AXIS OF LAKE MICHIGAN HELPED TO
CREATE A LAKE EFFECT PRECIP BAND. NORTH-NORTHEAST FLOW PUSHED THE
BAND ONSHORE FROM PORT WASHINGTON SOUTH TO KENOSHA AND WAUKEGAN.
LAKE EFFECT PUSHED WELL INLAND...NOW AFFECTING PARTS OF EASTERN DANE
COUNTY. THE PRECIP IS FALLING IN THE FORM OF RAIN RIGHT ALONG THE
SHORELINE AND AS SNOW INLAND. SOME OF THE HEAVIER RETURNS ON RADAR
OVER MKE HAVE BEEN REPORTED AS SNOW BY THE OBSERVER AT THE AIRPORT.
THE LAKE EFFECT BAND APPEARS TO BE SLOWLY SHIFTING SOUTHWARD THIS
AFTERNOON. THE SNOW/DRIZZLE COULD VERY WELL END AT MITCHELL AIRPORT
BY 2 PM AND NOT RETURN FOR THE REST OF THE DAY DUE TO DRIER AIR IN
NORTHEAST WI WORKING ITS WAY SOUTHWARD. WILL NEED TO MONITOR RADAR
TRENDS.
THERE WAS A PERIOD OF SNOW AT THE NWS OFFICE NEAR DOUSMAN/SULLIVAN
THAT HAD DENDRITE SNOW CRYSTALS...BUT THE MAJORITY OF THE SNOWFLAKES
HAVE BEEN VERY SMALL. RUC SNDGS SHOWING SATURATED LAYER UP TO 4 TO
5KFT...WITH A FAIRLY DEEP LAYER IN THE -8 TO -10C TEMP
AREA...LEADING TO SMALL ICE CRYSTALS RATHER THAN LARGER DENDRITES.
MEANWHILE...AN AREA OF LIGHT SNOW ASSOCIATED WITH PERSISTENT
VORTICITY ADVECTION SET UP ACROSS NORTHERN WI YESTERDAY AND IS
SLOWLY SHIFTING SOUTHWARD TODAY. MODELS SHOW THE AREA OF SNOW
ORIENTING ITSELF MORE NORTHWEST/SOUTHEAST BY LATE THIS AFTERNOON. WE
CAN EXPECT THE SLIGHT SNOW OVER WEST CENTRAL WI TO SHIFT INTO SOUTH
CENTRAL WI LATER THIS AFTERNOON. IT IS QUESTIONABLE IF THE FAR
SOUTHWEST FORECAST AREA WILL SEE THIS SNOW.
&&
.AVIATION/18Z TAFS/...
LOW-LEVEL MOISTURE WILL BE TRAPPED UNDER AN INVERSION ACROSS
SOUTHERN WISCONSIN THROUGH THE DAY TODAY...SO STRATUS WILL HOLD
IN THROUGH THE FORECAST PERIOD. MVFR CIGS ARE EXPECTED TO IMPROVE TO
VFR LATE THIS AFTERNOON AS DRIER AIR OVER NORTHEAST WI WORKS INTO
THE AREA.
LAKE EFFECT PRECIP PUSHING ONSHORE SOUTH OF PORT WASHINGTON EARLY
THIS AFTERNOON. THE PRECIP IS FALLING IN THE FORM OF RAIN RIGHT
ALONG THE SHORELINE AND AS SNOW INLAND. SOME OF THE HEAVIER RETURNS
ON RADAR OVER MKE HAVE BEEN REPORTED AS SNOW AND DRIZZLE BY THE
OBSERVER AT THE AIRPORT.
THE LAKE EFFECT BAND APPEARS TO BE SLOWLY SHIFTING SOUTHWARD THIS
AFTERNOON. THE SNOW/DRIZZLE COULD VERY WELL END AT MITCHELL AIRPORT
BY 2 PM AND NOT RETURN FOR THE REST OF THE DAY DUE TO DRIER AIR IN
NORTHEAST WI WORKING ITS WAY SOUTHWARD. PRECIP SHOULD PERSIST AT ENW
A WHILE LONGER. WILL NEED TO MONITOR RADAR TRENDS.
THERE COULD BE ANOTHER ROUND OF LAKE EFFECT SHOWERS TO CONTEND WITH
TUE MORNING FROM MKE SOUTHWARD. PLENTY OF UNCERTAINTY AT THIS TIME.
&&
.MARINE...
PERSISTENT 10 TO 20 KNOT NORTH WINDS BUILDING 3 TO 5 FOOT WAVES.
THOUGH WINDS BEGIN TO EASE BY TUESDAY MORNING AND THEN BACK
NORTHWEST TUESDAY AFTERNOON...WAVES WILL BE SLOWER
TO SUBSIDE...SO SMALL CRAFT ADVISORY IN EFFECT THROUGH 6 PM
TUESDAY. LAKE-EFFECT SNOW/RAIN SHOWERS WILL ALSO
REDUCE VISIBILITIES AT TIMES THROUGH TUESDAY AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST TUESDAY FOR LMZ643>646.
&&
$$
UPDATE...MRC