Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/10/12
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND JUNCTION CO
923 PM MST SAT JAN 7 2012
.UPDATE...
THE UPPER LEVEL TROUGH CONTINUES TO SAG SOUTH WITH SNOW WINDING
DOWN OVER ALL OF THE NORTHERN ZONES. STILL SOME AREAS OF
CONCENTRATED HEAVIER SNOW FALLING OVER THE CENTRAL MOUNTAINS AND
LIGHT SNOW LINGERING ALONG THE INTERSTATE 70 CORRIDOR FROM
GLENWOOD CANYON EAST TO AVON. SO WILL HANG ON TO THOSE ADVISORIES
FOR A FEW MORE HOURS...BUT REMAINDER OF HIGHLIGHTS HAVE BEEN
DROPPED.
&&
.AVIATION /FOR 06Z TAF ISSUANCE/...
SNOW SHOWERS WILL COME TO A GRADUAL END OVERNIGHT THROUGHOUT
WESTERN COLORADO AND EASTERN UTAH. LOW STRATUS DECKS EXPECTED IN
MANY OF THE LOWER VALLEYS BY EARLY SUNDAY MORNING...WITH PATCHY
FOG RESTRICTED VISIBILITIES AT TIMES. EXPECT AREAS OF MVFR AND IFR
CIGS AND VSBYS FROM 06Z THROUGH 15Z SUNDAY. VFR CONDITIONS ARE
THEN EXPECTED TO RETURN TO EASTERN UTAH AND WESTERN COLORADO BY
MIDDAY SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 548 PM MST SAT JAN 7 2012/...
.UPDATE...
CONTINUING TO PULL BACK THE WINTER WEATHER HIGHLIGHTS BASED ON
LATEST SURFACE OBS AND SPOTTER REPORTS. HAVE NOW CANCELLED THE
NORTHWEST PLATEAU IN NORTHWEST COLORADO AS SNOW HAS ENDED AT CRAIG
AND MEEKER AND CEILINGS CONTINUE TO LIFT. RADAR RETURNS SUPPORT
HIGHLIGHTS OVER THE CENTRAL ZONES...JUST AHEAD OF THE UPPER LEVEL
TROUGH THAT IS SAGGING THROUGH THE FORECAST AREA...SO NO OTHER
ADJUSTMENTS PLANNED AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 448 PM MST SAT JAN 7 2012/...
.UPDATE...
SNOWFALL COMING TO A RAPID END ACROSS THE EASTERN UINTA MOUNTAINS
LATE THIS AFTERNOON BASED ON CURRENT WEB CAMS IN THE REGION. AS A
RESULT...HAVE DROPPED THE WINTER WEATHER ADVISORY FOR THIS AREA
AND ADJUSTED THE CHANCE OF PRECIPITATION FOR THE REMAINDER OF THIS
EVENING. BASED ON CURRENT TRACK AND SPEED OF THE UPPER LEVEL
LOW...ADDITIONAL ADJUSTMENTS MAY BE NEED TO CURRENT WINTER
HIGHLIGHTS. WILL CONTINUE TO MONITOR.
&&
.PREV DISCUSSION... /ISSUED 305 PM MST SAT JAN 7 2012/
.SHORT TERM /TONIGHT THROUGH MONDAY/...
LATEST MOSAIC IMAGERY SHOWING LARGE BAND OF SNOW MOVING ACROSS
BOOKCLIFFS THEN EASTWARD ALONG INTERSTATE 70 TOWARDS GLENWOOD
SPRINGS AND EAGLE. CDOT WEBCAMS ALSO SHOWING PLENTY OF SNOW ALONG
THE CORRIDOR. CROSS-SECTIONS INDICATE RATHER LARGE AREA OF
CONDITIONAL SYMMETRIC INSTABILITY MATCHING UP WITH THIS BAND WHICH
WOULD EXPLAIN THE RAPID SNOW ACCUMULATIONS AT THE SFC DUE TO SOME
SLANTWISE CONVECTION. IF THE BAND STAYS TOGETHER AND CONTINUES TO
DROP SWRD...SOME QUICK ACCUMULATIONS ARE POSSIBLE OVER GRASSY
SURFACES OVER GRAND VALLEY AND AREAS SOUTH. HAVING SAID THAT...MODELS
DO KEEP THIS BAND TO OUR NORTH WITH SOME SLOW SWRD DRIFT THROUGH
THE AFTN AND EVENING. NORTH OF THIS AREA...SNOW CONTINUES TO FALL
OVER AND NEAR CRAIG...HAYDEN AND MEEKER. HILITES APPEAR TO BE ON
TRACK WITH SOME CONCERN REMAINING FOR THE UNCOMPAHGRE PLATEAU AND
NRN SAN JUANS AS RUC AND HRRR SHOW SOME DEVELOPMENT OVER THAT
AREA. OF COURSE...18Z NAM SHOWS SOME PRECIP BUT NOT ENOUGH TO
WARRANT ANY ADVISORIES. WILL NOT PULL THE TRIGGER YET BUT WILL
KEEP AN EYE ON WEBCAMS...RADAR...SATELLITE AND LOCAL SNOW REPORTS.
SFC COLD FRONT MOVED THROUGH AREA QUICKER THAN EXPECTED AND IS
CLEARLY SEEN ON WATER VAPOR AND IR IMAGERY MOVING OVR SERN CO AND
NRN NM. THE UPPER LEVEL TROF AND UPPER LOW REMAIN OVER NERN UT
ATTM AND ARE STILL EXPECTED TO MOVE OVER THE REGION THIS AFTN INTO
TONIGHT CAUSING MORE SNOWFALL. THUS...MADE LITTLE TO NO CHANGE FOR
OVERNIGHT FORECAST. SINCE SPEED OF SYSTEM HAS INCREASED
SOMEWHAT...AGREE WITH PREVIOUS THINKING THAT HILITES MAY HAVE TO
BE TAKEN DOWN EARLY PROBABLY NEARER TO EARLY SUNDAY MORNING. WILL
LEAVE AS IS FOR NOW.
BY SUNDAY...MOSTLY SUNNY SKIES FOR AREAS N AND CLEARING SKIES FOR
THE SOUTH. TEMPS WILL RUN NEAR NORMAL FOR THIS TIME OF YEAR...OR
ABOUT 10 DEGREES COOLER THAN SEEN THIS PREVIOUS WEEK. HIGH
PRESSURE WILL BUILD IN AND PERSIST THROUGH MID-WEEK.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
EASTERN UTAH AND WESTERN COLORADO WILL BE UNDER THE INFLUENCE OF AN
UPPER RIDGE MONDAY NIGHT AND TUESDAY...SQUEEZED BETWEEN A WRAPPED UP
SOUTHERN PLAINS LOW AND THE NEXT TROF ARRIVING OUT OF THE NORTHEAST
PACIFIC. AS SUCH THE DRY WEATHER WILL CONTINUE OVER THIS PERIOD WITH
THE WARMING ALOFT HELPING TO ENFORCE THE LOW LEVEL
INVERSIONS...ESPECIALLY IN AREAS WITH THE NEWER SNOW COVER AND DID
DIRECT TEMPERATURES TOWARD THE LOWER END OF GUIDANCE. BEYOND THIS
PERIOD CONFIDENCE CONTINUES TO WANE WITH DIFFERING MED RANGE MODEL
SOLUTIONS RELATED TO PROGRESSION OF THE WESTERN TROF. THE
DIFFERENCES ARE MOSTLY CENTERED AROUND THE EVOLUTION OF AN UPPER LOW
OVER THE SOUTHWEST CORNER OF THE CONUS AS ENERGY IN THE TROF SPLITS.
THE OPERATIONAL GFS SOLUTION IS SLOWER TO ACHIEVE THIS SPLIT WHICH
CONFLICTS WITH SOME OF IT/S MEMBERS AND WITH A REFLECTION OF A LOW
OFF THE SOCAL COAST IN THE H5 MEAN SOLUTION. THIS SLOWER SOLUTION
WOULD BE A WETTER SOLUTION AND IMPACT MORE OF THE CWA. FOR NOW
FORECAST CONTINUES TO LEAN AWAY FROM THIS TOWARD THE EURO WITH A
MORE NORTHERLY FLOW DOMINATING TUESDAY NIGHT INTO WEDNESDAY AS A
CLIPPER TYPE SYSTEM DROPS THROUGH THE NORTHERN PLAINS. THIS WOULD
BRING SOME OROGRAPHICS AND WEAK DYNAMICS TO THE CENTRAL AND NORTHERN
MOUNTAINS FOR A SLIGHT CHANCE OF SNOW. BEHIND THIS REX BLOCK SETS UP
IN THE WEST WITH DRY AND ABOVE NORMAL TEMPERATURES RETURNING TO THE
CWA FOR THE LAST HALF OF THE WEEK.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MST SUNDAY FOR ZONES 008>010-
012.
UT...NONE.
&&
$$
UPDATE.......JDC
SHORT TERM...TGR
LONG TERM....15
AVIATION.....JDC
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
935 PM EST Mon Jan 9 2012
.UPDATE...
02Z Water vapor and H4 RUC analysis shows a complex upper level
pattern in place across the CONUS this evening. Main northern stream
flow arrives across the Pacific NW while ridging up into SC Canada.
This flow then dives back to the southeast forming longwave
troughing across the NE states and eastern Canadian Provinces. Other
feature of note, and most important to our forecast is a large
cut-off upper low spinning over TX. WV imagery shows abundant
mid/upper level moisture streaming east/NE ahead of this feature
along the northern Gulf Coast. Synoptic support ahead of the low is
combining with deep WAA pattern to produce a large area of showers
and storms along and south of the LA coastline. This weather will
enter our forecast later Tuesday and Tuesday night, however for the
rest of the overnight, our weather will remain dry and quiet,
outside of areas of fog. 00Z KTLH sounding shows a fairly dry
profile in the middle and lower levels this evening, however the
upper level moisture mentioned above can be seen overriding the
region above around 400mb. This moisture will be lowering with time
overnight resulting in a mostly cloudy forecast for your Tuesday.
Once again, fog will be the main forecast concern during the early
morning hours. Hi-res guidance is generally hinting toward better
fog potential in the western zones associated with a developing weak
southerly flow. While some fog is certainly possible overnight, the
areal coverage and persistence of the fog does not appear as
impressive as previous nights. This is especially true noting the
amount of mid/high level clouds overspreading the region which
should have some influence in slowing the radiative process. Still a
bit early in the evening to determine the degree to which this
higher level moisture will impact the fog forecast, so will not make
any significant changes with this update package.
Temperatures appear on track with lows generally dropping into the
lower to middle 50s. Will expect a few mid/upper 40s over toward the
SE big bend and Suwannee River Valley in closer proximity to the
surface high.
&&
.PREVIOUS FORECAST...(TUESDAY THROUGH THURSDAY).
The 12 UTC model suite remains on track, bringing a strong cold
front through our forecast area Wednesday morning. The NAM is still
a little slower than the global models, but the global models are a
bit slower than their previous runs so the timing differences are
smaller than 24 hours ago. With strong Q-G forcing and ample deep
layer moisture, there is almost no question as to whether or not it
will rain here, it`s just a matter of when. Our PoP for Tuesday
night/Wednesday morning is about 80%, but this will probably come up
to near 100% in subsequent forecast packages once the timing becomes
more certain. Our storm total QPF for this even is about an inch
areawide, but of course a few locations could get double or triple
this amount in the heavier storms. Temperatures behind this cold
front will not be very cold, and lows Thursday morning will return
to near average (lower to mid 40s) with mostly clear skies and a dry
airmass in place. A stronger (but dry) cold front will pass through
our forecast area Thursday afternoon and evening, but will not
arrive in time to prevent high temperatures from reaching the upper
60s to lower 70s.
Not much has changed with regard to the severe weather potential for
Tuesday night and Wednesday morning. All indications continue to
suggest another high-shear/low CAPE environment for our region as
the squall line moves through. The SPC subjective Convective
Outlook, the 09 UTC SREF, and our local objective severe weather
probability forecasts show the chances for severe storms at about 5%
within 25 miles of a point. This looks reasonable based on our
experience with such cases. There may have been a subtle change in
the model forecast wind profiles, which now suggest a less curved
hodograph (but still strong shear magnitudes). This would indicate
more of a threat for damaging wind gusts in LEWPs, and still
possibly a weak, short-lived tornado. This is more likely where the
greatest SBCAPE coincided with the squall line, which right now
appears to be the FL Panhandle (west of the Apalachicola River). By
tomorrow the high-resolution NWP guidance will have the event within
its forecast time, and we will be able to examine updraft speeds and
helicity to confirm the overall severe weather threat.
&&
.MARINE...Southeasterly flow will gradually increase on Tuesday
ahead of an approaching storm system. Winds and seas will
potentially build to advisory levels by Tuesday night into Wednesday
as the system moves across the marine area. Winds will briefly
decrease behind this system as high pressure builds back over the
waters. A dry cold front will sweep through the marine area on
Thursday night resulting in another, albeit brief, increase in winds
and seas before another high pressure area returns for the weekend.
&&
.AVIATION...
VFR conditions this evening will once again give way to IFR/LIFR
conditions at most terminals beginning around 04z at ECP and
spreading NE/E to rest of terminals before sunrise on Tuesday. Will
be showing at least IFR conditions at all sites, but expect a long
duration period of LIFR conditions at TLH/ECP/DHN as a large fog
area develops and spreads inland. Conditions at these sites should
be slow to improve in the morning, with VFR conditions not expected
to return until the 15z to 17z timeframe. Leading edge of rain will
begin wrn terminals mid aftn and spread N/NE with MVFR CIGS/VSBYS.
Will go with TEMPO at DHN and ECP and prob30 at TLH and KABY.
-
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 55 72 56 67 43 / 10 50 80 40 10
Panama City 59 69 57 64 46 / 20 60 80 20 10
Dothan 57 69 55 67 44 / 20 60 80 20 10
Albany 54 70 55 65 44 / 10 60 80 50 10
Valdosta 49 73 56 68 44 / 10 30 70 70 0
Cross City 51 74 56 70 45 / 10 10 50 70 10
Apalachicola 57 68 61 66 50 / 10 40 80 30 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
UPDATE...MROCZKA
AVIATION...BLOCK/TSAPARIS
PREVIOUS FORECAST...FOURNIER
AREA FORECAST DISCUSSION...CORRECTED
NWS CARIBOU ME
550 AM EST SUN JAN 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY THROUGH MONDAY.
ANOTHER LOW PRESSURE FROM CENTRAL CANADA WILL MOVE WELL NORTH OF
THE STATE ON TUESDAY. ANOTHER HIGH PRESSURE SYSTEM FROM NORTHERN
CANADA WILL BRIEFLY RIDGE ACROSS THE REGION ON WEDNESDAY BEHIND
A COLD FRONT LATE TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...AN EAST-WEST COLD FRONT CURRENTLY BISECTS THE FORECAST
AREA WHICH WILL CONTINUE TO SLOWLY SINK SOUTH TODAY. HAVE NOTED A THIN
STREAMER OF SNOW ACROSS NORTHERN SOMERSET AND PISCATAQUIS COUNTIES
EARLY THIS MORNING JUST ON THE NORTH SIDE OF THIS BOUNDARY. THIS
SHOULD GRADUALLY WEAKEN AND BE REPLACED BY ANOTHER STRONGER BAND A
BIT FURTHER NORTH AS WESTERLY WINDS BECOME MORE NORTHWEST. HAVE
UPDATED THE FORECAST TO ACCOUNT FOR THIS ACTIVITY...BUT NO OTHER
MAJOR CHANGES NEEDED.
PREVIOUS DISCUSSION...HIGH PRESSURE OVER THE GREAT LAKES WILL SLOWLY BUILD
EASTWARD TOWARD MAINE TODAY. A COLD FRONT THAT IS CURRENTLY DRAPED
ACROSS NORTHERN MAINE WILL SLIDE SOUTH THROUGH THE REMAINDER OF
THE AREA BY THIS AFTERNOON. SKIES HAVE CLEARED OVER THE SOUTHERN
THIRD OF THE FORECAST AREA WHILE NORTHERN AREAS REMAIN MOSTLY
CLOUDY BEHIND THE FRONT. COLDER AIR WILL SPILL INTO THE FORECAST
AREA THROUGH THE DAY AS NORTH FLOW PUSHES THE FRONT SOUTHWARD. THE
12KM NAM...3KM HRRR AND THE REGIONAL CANADIAN ALL INDICATE THAT A
NW-SE ORIENTED SNOW BAND WILL DEVELOP ACROSS THE FORECAST AREA
THIS MORNING...A RESULT OF THE COLDER AIR ALOFT MOVING OVER THE
RELATIVELY WARM WATERS OF THE SAINT LAWRENCE. THE BAND SHOULD SET
UP BY MID MORNING BUT WILL GRADUALLY DISSIPATE THIS AFTERNOON AS
THE FLOW LESSENS AS THE HIGH DRAWS NEAR. THE STEADIEST SNOW LOOKS
TO SET UP ACROSS THE NORTHERN MAINE WOODS AND EXTEND SOUTHEAST
TOWARD PATTEN AND KINGMAN WITH SNOWFALL AMOUNTS AROUND A HALF
INCH. ON EITHER SIDE AND DOWNWIND OF THIS BAND THERE`S JUST A
SLIGHT CHANCE OF SNOW SHOWERS SO LITTLE TO NO ACCUMULATION IS
EXPECTED IN THESE AREAS. AWAY FROM THE SNOWY AREAS...SKIES WILL BE
PARTLY TO MOSTLY SUNNY THROUGH THE DAY. THE SNOW SHOWERS WILL WANE
AND CLOUDS LESSEN LATE THIS AFTERNOON...WITH ALL AREAS MOSTLY
CLEAR BY THIS EVENING.
THE HIGH WILL BUILD OVER THE REGION OVERNIGHT TONIGHT...CRESTING
EARLY TOMORROW MORNING. CLEAR SKIES AND LIGHT WINDS WILL ALLOW FOR
GOOD RADIATIONAL COOLING. THEREFORE EXPECT A CHILLY NIGHT TONIGHT.
NORTHERN AREAS WILL BOTTOM OUT IN THE SINGLE DIGITS BELOW ZERO WHILE
THE USUAL COLD SPOTS IN NORTHWEST MAINE WILL DIP TO 10 TO 15 BELOW.
FURTHER SOUTH...CENTRAL AND SOUTHERN MAINE CAN EXPECT LOWS IN THE
SINGLE DIGITS ABOVE ZERO.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SFC HI PRES WILL CROSS THE FA ON MON WITH PATCHY MID CLDNSS AS A
WEAK UPPER TROF MOVES EAST INTO THE MARITIMES. RETURN SW FLOW SETS
UP LATE IN THE DAY BEHIND THE HI AS MID CLDNSS INCREASES FROM THE
W IN THE EVE. A S/WV MOVG EWRD WILL THEN BRING SN SHWRS TO MSLY
NRN PTNS OF THE FA LATE MON NGT INTO TUE AS SFC LOW PRES TRACK
WELL N OF THE FA. UNLIKE THIS PAST EVENT...WHERE A STRONG W-E QUASI-
STATIONARY FRONTAL BOUNDARY WAS IN PLACE JUST S OF OUR FA TO
ENHANCE THE OVRRNG SNFL OVR SPCLY NRN PTNS OF THE FA...THIS S/WV
WILL NOT HAVE THIS TYPE OF BOUNDARY...SO SNFL IS ANTICIPATED TO
BE MUCH LIGHTER...WITH ARND AN INCH OVR FAR NRN PTNS OF THE FA
LATE MON NGT THRU TUE AND LESSER AMOUNTS PROGRESSIVELY FURTHER S.
A MDT SFC COLD FRONT BEHIND THE S/WV CROSSING THE FA LATE TUE AFTN
INTO EVE WILL BRING THE S FRINGE OF ARCTIC AIR BACK INTO SPCLY NRN
PTNS OF THE FA BY LATE TUE NGT INTO MORN WITH A BRISK EVENING WIND
SLACKENING BY WED MORN. CLDS QUICKLY INCREASE OVR THE FA FROM THE
W AS THE ARCTIC AIR ALREADY BEGINS TO LIFT NWRD FROM OUR FA. SN
SHWRS OR VERY LGT STEADY SN WILL ACCOMPANY THE 850 MB WARM FRONT
WED NGT ACROSS CNTRL AND NRN PTNS OF THE FA WITH LITTLE IN THE WAY
OF ACCUMULATION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
MODELS APPEAR TO BE MORE IN AGREEMENT WITH BRINGING THE SRN GULF
COAST STATES S/WV AND ASSOCIATED SFC LOW TOWARD OUR FA ON THU IN
ADVANCE OF THE STRONGER MORE AMPLIFIED S/WV FROM THE GREAT LKS.
THIS SHOULD KEEP THE TRACK OF THE SFC LOW E OF THE FA...AND INDEED
A MORE ERN GFS TRACK IS CURRENTLY BEING SUPPORTED BY THE 00Z
ECMWF AND NOW THE 00Z CANGEM SOLUTION...WHERE THE PRIOR 12Z
SOLUTION WAS AN OUTLIER...TAKING THE SFC LOW ON A WRN TRACK W OF
OUR FA...WHICH WOULD HAVE BROUGHT MILD ATLC AIR INTO ALL OF OUR FA
BY THU NGT. THE CANGEM PRECIP ONSET ALSO AGREES MORE WITH THE
FASTER GFS AND GFS ENS MEAN TIMING RATHER THAN THE SLOWER ECMWF
ONSET. ALL MODELS KEEP LLVL COLD AIR IN PLACE OVR THE FA N OF
DOWNEAST ME THU INTO THU EVE...BUT SHOW A NWRD PUNCH OF WARM AIR
ALF WHICH COULD LIKELY RESULT IN A PD OF MIXED PRECIP OVR E CNTRL
AND N CNTRL PTNS OF THE FA THU AFT AND EVE. MIXED PRECIP COULD
POSSIBLE REACH EVEN INTO FAR NRN PTNS OF THE FA THU EVE BEFORE COLD
MID LVL COLD ADVCN CHGS PRECIP BACK TO A PD OF ALL SN BEFORE
TAPERING TO SN SHWRS LATE THU NGT...BUT PRECIP TYPES AND TRANSITIONS
ACROSS THE FA REMAIN SPECULATIVE WITH THIS EVEN ATTM. WE NOTED
LESSER QPF SHOWN BY MOST LONGER RANGE MODELS WITH THIS SYSTEM...
AND IT COULD BE THAT THE S/WV MAY BE INITIALIZED THIS MODEL CYCLE
IN LOW RESOLUTION PTN OF THE MODEL DOMAIN...WHICH HAS HAPPENED
WITH SEVERAL OTHER SYSTEMS THIS PAST WINTER FROM DAYS 3 TO 6 OUT.
WE STILL KEEP POPS IN THE LIKELY CATEGORY DUE TO THIS UNCERTAINTY...
BUT STILL BELIEVE A SIG PRECIP SYSTEM IS LIKELY DURG THIS PD.
ALSO NOTED ON THIS MODEL CYCLE WAS THAT THE ECMWF BACKED OFF ITS
SECOND SFC LOW DEVELOPING WITH THE GREAT LKS S/WV FOR FRI INTO FRI
NGT AND APPEARS MORE LIKE THE 00Z GFS WITH THIS ASPECT OF THE
FCST. IF INDEED...THIS IS THE LIKELY OUTCOME...CLDS AND SN SHWRS
CAN BE XPCTD ON FRI WITH INCREASING LLVL COLD ADVCN AS SFC
REFLECTIONS FROM THE SRN AND NRN S/WVS MERGE OVR THE CAN MARITIME
PROVINCES. CLRG AS WELL AS COLD AND BRISK CONDITIONS IS XPCTD ATTM
FOR FRI NGT INTO SAT AS ARCTIC AIR FROM NRN CAN ADVECTS INTO THE
FA.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MAINLY MVFR/VFR EXPECTED THROUGH THE PERIOD. THE NORTHERN
TERMINALS WILL REMAIN MVFR THROUGH MUCH OF TODAY DUE TO LOW CEILINGS
AND OCCASIONAL SNOW SHOWERS. FURTHER SOUTH...MVFR IS POSSIBLE EARLY
THIS MORNING IN PATCHY FOG BUT OVERALL EXPECT VFR CONDITIONS. SNOW
SHOWERS WILL END LATE THIS AFTERNOON AND SKIES CLEAR BY THIS
EVENING. VFR EXPECTED AT ALL SITES AFTER 00Z MONDAY.
SHORT TERM:VFR XPCTD ALL SITE XPCTD MON THRU MON EVE...THEN MVFR
LIKELY LATE MON NGT THROUGH TUE WITH SN SHWRS SPCLY NRN TAF SITES
WHERE BRIEF IFR IS POSSIBLE. CONDITIONS IMPROVE ALL SITES TO VFR
TUE NGT AND CONT WED. NEXT CHC OF MVFR WILL BEGIN LATE WED NGT
IN OCNL LGT SN WITH CONDITIONS LIKELY LOWERING TO IFR ON THU IN
STEADIER SN NRN FAR TAF SITES...MIXED PRECIP AT KHUL AND MSLY RN
FOR DOWNEAST SITES.
&&
.MARINE...
NEAR TERM: WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT LEVELS
TODAY AND TONIGHT SO NO HEADLINES WILL BE NEEDED.
SHORT TO LONG TERM: NO HDLNS MON THRU MOST OF MON NGT...WITH
MARGINAL SCA WINDS AND SEAS POSSIBLE ON TUE INTO ERLY TUE EVE
WITH SW FLOW AHEAD OF...AND BRIEF NW FLOW BEHIND A COLD FRONT.
WINDS AND SEAS SHOULD LOWER WELL BLO SCA CRITERIA LATE TUE NGT
THRU WED EVE...PERHAPS INCREASING TO SCA AHEAD OF LOW PRES FROM
THE SW LATE WED NGT INTO THU. WE USED A BLEND OF 00Z NAM12 AND GFS40
FOR SHORT TERM WINDS AND GFS40 AND GMOS FOR LONG TERM. WV HTS WERE
DERIVED FROM A BLEND OF WW3...SWAN NAM AND SWAN GFS GUIDANCE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
546 AM EST SUN JAN 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY THROUGH MONDAY.
ANOTHER LOW PRESSURE FROM CENTRAL CANADA WILL MOVE WELL NORTH OF
THE STATE ON TUESDAY. ANOTHER HIGH PRESSURE SYSTEM FROM NORTHERN
CANADA WILL BRIEFLY RIDGE ACROSS THE REGION ON WEDNESDAY BEHIND
A COLD FRONT LATE TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...AN EAST-WEST COLD FRONT CURRENTLY BISECTS THE FORECAST
AREA AND WILL CONTINUE TO SLOWLY SINK SOUTH TODAY. HAVE NOTED A THIN
STREAMER OF SNOW ACROSS NORTHERN SOMERSET AND PISCATAQUIS COUNTIES
EARLY THIS MORNING JUST ON THE NORTH SIDE OF THIS BOUNDARY. THIS
SHOULD GRADUALLY WEAKEN AND BE REPLACED BY ANOTHER STRONGER BAND A
BIT FURTHER NORTH AS WESTERLY WINDS BECOME MORE NORTHWEST. HAVE
UPDATED THE FORECAST TO ACCOUNT FOR THIS ACTIVITY...BUT NO OTHER
MAJOR CHANGES NEEDED.
PREVIOUS DISCUSSION...HIGH PRESSURE OVER THE GREAT LAKES WILL SLOWLY BUILD
EASTWARD TOWARD MAINE TODAY. A COLD FRONT THAT IS CURRENTLY DRAPED
ACROSS NORTHERN MAINE WILL SLIDE SOUTH THROUGH THE REMAINDER OF
THE AREA BY THIS AFTERNOON. SKIES HAVE CLEARED OVER THE SOUTHERN
THIRD OF THE FORECAST AREA WHILE NORTHERN AREAS REMAIN MOSTLY
CLOUDY BEHIND THE FRONT. COLDER AIR WILL SPILL INTO THE FORECAST
AREA THROUGH THE DAY AS NORTH FLOW PUSHES THE FRONT SOUTHWARD. THE
12KM NAM...3KM HRRR AND THE REGIONAL CANADIAN ALL INDICATE THAT A
NW-SE ORIENTED SNOW BAND WILL DEVELOP ACROSS THE FORECAST AREA
THIS MORNING...A RESULT OF THE COLDER AIR ALOFT MOVING OVER THE
RELATIVELY WARM WATERS OF THE SAINT LAWRENCE. THE BAND SHOULD SET
UP BY MID MORNING BUT WILL GRADUALLY DISSIPATE THIS AFTERNOON AS
THE FLOW LESSENS AS THE HIGH DRAWS NEAR. THE STEADIEST SNOW LOOKS
TO SET UP ACROSS THE NORTHERN MAINE WOODS AND EXTEND SOUTHEAST
TOWARD PATTEN AND KINGMAN WITH SNOWFALL AMOUNTS AROUND A HALF
INCH. ON EITHER SIDE AND DOWNWIND OF THIS BAND THERE`S JUST A
SLIGHT CHANCE OF SNOW SHOWERS SO LITTLE TO NO ACCUMULATION IS
EXPECTED IN THESE AREAS. AWAY FROM THE SNOWY AREAS...SKIES WILL BE
PARTLY TO MOSTLY SUNNY THROUGH THE DAY. THE SNOW SHOWERS WILL WANE
AND CLOUDS LESSEN LATE THIS AFTERNOON...WITH ALL AREAS MOSTLY
CLEAR BY THIS EVENING.
THE HIGH WILL BUILD OVER THE REGION OVERNIGHT TONIGHT...CRESTING
EARLY TOMORROW MORNING. CLEAR SKIES AND LIGHT WINDS WILL ALLOW FOR
GOOD RADIATIONAL COOLING. THEREFORE EXPECT A CHILLY NIGHT TONIGHT.
NORTHERN AREAS WILL BOTTOM OUT IN THE SINGLE DIGITS BELOW ZERO WHILE
THE USUAL COLD SPOTS IN NORTHWEST MAINE WILL DIP TO 10 TO 15 BELOW.
FURTHER SOUTH...CENTRAL AND SOUTHERN MAINE CAN EXPECT LOWS IN THE
SINGLE DIGITS ABOVE ZERO.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SFC HI PRES WILL CROSS THE FA ON MON WITH PATCHY MID CLDNSS AS A
WEAK UPPER TROF MOVES EAST INTO THE MARITIMES. RETURN SW FLOW SETS
UP LATE IN THE DAY BEHIND THE HI AS MID CLDNSS INCREASES FROM THE
W IN THE EVE. A S/WV MOVG EWRD WILL THEN BRING SN SHWRS TO MSLY
NRN PTNS OF THE FA LATE MON NGT INTO TUE AS SFC LOW PRES TRACK
WELL N OF THE FA. UNLIKE THIS PAST EVENT...WHERE A STRONG W-E QUASI-
STATIONARY FRONTAL BOUNDARY WAS IN PLACE JUST S OF OUR FA TO
ENHANCE THE OVRRNG SNFL OVR SPCLY NRN PTNS OF THE FA...THIS S/WV
WILL NOT HAVE THIS TYPE OF BOUNDARY...SO SNFL IS ANTICIPATED TO
BE MUCH LIGHTER...WITH ARND AN INCH OVR FAR NRN PTNS OF THE FA
LATE MON NGT THRU TUE AND LESSER AMOUNTS PROGRESSIVELY FURTHER S.
A MDT SFC COLD FRONT BEHIND THE S/WV CROSSING THE FA LATE TUE AFTN
INTO EVE WILL BRING THE S FRINGE OF ARCTIC AIR BACK INTO SPCLY NRN
PTNS OF THE FA BY LATE TUE NGT INTO MORN WITH A BRISK EVENING WIND
SLACKENING BY WED MORN. CLDS QUICKLY INCREASE OVR THE FA FROM THE
W AS THE ARCTIC AIR ALREADY BEGINS TO LIFT NWRD FROM OUR FA. SN
SHWRS OR VERY LGT STEADY SN WILL ACCOMPANY THE 850 MB WARM FRONT
WED NGT ACROSS CNTRL AND NRN PTNS OF THE FA WITH LITTLE IN THE WAY
OF ACCUMULATION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
MODELS APPEAR TO BE MORE IN AGREEMENT WITH BRINGING THE SRN GULF
COAST STATES S/WV AND ASSOCIATED SFC LOW TOWARD OUR FA ON THU IN
ADVANCE OF THE STRONGER MORE AMPLIFIED S/WV FROM THE GREAT LKS.
THIS SHOULD KEEP THE TRACK OF THE SFC LOW E OF THE FA...AND INDEED
A MORE ERN GFS TRACK IS CURRENTLY BEING SUPPORTED BY THE 00Z
ECMWF AND NOW THE 00Z CANGEM SOLUTION...WHERE THE PRIOR 12Z
SOLUTION WAS AN OUTLIER...TAKING THE SFC LOW ON A WRN TRACK W OF
OUR FA...WHICH WOULD HAVE BROUGHT MILD ATLC AIR INTO ALL OF OUR FA
BY THU NGT. THE CANGEM PRECIP ONSET ALSO AGREES MORE WITH THE
FASTER GFS AND GFS ENS MEAN TIMING RATHER THAN THE SLOWER ECMWF
ONSET. ALL MODELS KEEP LLVL COLD AIR IN PLACE OVR THE FA N OF
DOWNEAST ME THU INTO THU EVE...BUT SHOW A NWRD PUNCH OF WARM AIR
ALF WHICH COULD LIKELY RESULT IN A PD OF MIXED PRECIP OVR E CNTRL
AND N CNTRL PTNS OF THE FA THU AFT AND EVE. MIXED PRECIP COULD
POSSIBLE REACH EVEN INTO FAR NRN PTNS OF THE FA THU EVE BEFORE COLD
MID LVL COLD ADVCN CHGS PRECIP BACK TO A PD OF ALL SN BEFORE
TAPERING TO SN SHWRS LATE THU NGT...BUT PRECIP TYPES AND TRANSITIONS
ACROSS THE FA REMAIN SPECULATIVE WITH THIS EVEN ATTM. WE NOTED
LESSER QPF SHOWN BY MOST LONGER RANGE MODELS WITH THIS SYSTEM...
AND IT COULD BE THAT THE S/WV MAY BE INITIALIZED THIS MODEL CYCLE
IN LOW RESOLUTION PTN OF THE MODEL DOMAIN...WHICH HAS HAPPENED
WITH SEVERAL OTHER SYSTEMS THIS PAST WINTER FROM DAYS 3 TO 6 OUT.
WE STILL KEEP POPS IN THE LIKELY CATEGORY DUE TO THIS UNCERTAINTY...
BUT STILL BELIEVE A SIG PRECIP SYSTEM IS LIKELY DURG THIS PD.
ALSO NOTED ON THIS MODEL CYCLE WAS THAT THE ECMWF BACKED OFF ITS
SECOND SFC LOW DEVELOPING WITH THE GREAT LKS S/WV FOR FRI INTO FRI
NGT AND APPEARS MORE LIKE THE 00Z GFS WITH THIS ASPECT OF THE
FCST. IF INDEED...THIS IS THE LIKELY OUTCOME...CLDS AND SN SHWRS
CAN BE XPCTD ON FRI WITH INCREASING LLVL COLD ADVCN AS SFC
REFLECTIONS FROM THE SRN AND NRN S/WVS MERGE OVR THE CAN MARITIME
PROVINCES. CLRG AS WELL AS COLD AND BRISK CONDITIONS IS XPCTD ATTM
FOR FRI NGT INTO SAT AS ARCTIC AIR FROM NRN CAN ADVECTS INTO THE
FA.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MAINLY MVFR/VFR EXPECTED THROUGH THE PERIOD. THE NORTHERN
TERMINALS WILL REMAIN MVFR THROUGH MUCH OF TODAY DUE TO LOW CEILINGS
AND OCCASIONAL SNOW SHOWERS. FURTHER SOUTH...MVFR IS POSSIBLE EARLY
THIS MORNING IN PATCHY FOG BUT OVERALL EXPECT VFR CONDITIONS. SNOW
SHOWERS WILL END LATE THIS AFTERNOON AND SKIES CLEAR BY THIS
EVENING. VFR EXPECTED AT ALL SITES AFTER 00Z MONDAY.
SHORT TERM:VFR XPCTD ALL SITE XPCTD MON THRU MON EVE...THEN MVFR
LIKELY LATE MON NGT THROUGH TUE WITH SN SHWRS SPCLY NRN TAF SITES
WHERE BRIEF IFR IS POSSIBLE. CONDITIONS IMPROVE ALL SITES TO VFR
TUE NGT AND CONT WED. NEXT CHC OF MVFR WILL BEGIN LATE WED NGT
IN OCNL LGT SN WITH CONDITIONS LIKELY LOWERING TO IFR ON THU IN
STEADIER SN NRN FAR TAF SITES...MIXED PRECIP AT KHUL AND MSLY RN
FOR DOWNEAST SITES.
&&
.MARINE...
NEAR TERM: WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT LEVELS
TODAY AND TONIGHT SO NO HEADLINES WILL BE NEEDED.
SHORT TO LONG TERM: NO HDLNS MON THRU MOST OF MON NGT...WITH
MARGINAL SCA WINDS AND SEAS POSSIBLE ON TUE INTO ERLY TUE EVE
WITH SW FLOW AHEAD OF...AND BRIEF NW FLOW BEHIND A COLD FRONT.
WINDS AND SEAS SHOULD LOWER WELL BLO SCA CRITERIA LATE TUE NGT
THRU WED EVE...PERHAPS INCREASING TO SCA AHEAD OF LOW PRES FROM
THE SW LATE WED NGT INTO THU. WE USED A BLEND OF 00Z NAM12 AND GFS40
FOR SHORT TERM WINDS AND GFS40 AND GMOS FOR LONG TERM. WV HTS WERE
DERIVED FROM A BLEND OF WW3...SWAN NAM AND SWAN GFS GUIDANCE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1020 PM EST MON JAN 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY AND MILD CONDITIONS THROUGH
TUESDAY. LOW PRESSURE, COMING NORTHEAST FROM LOUISIANA, WILL BRING RAIN
TO THE UPPER OHIO VALLEY WEDNESDAY INTO WEDNESDAY NIGHT. A COLD
FRONTAL PASSAGE THURSDAY WILL BRING SHARPLY COLDER TEMPERATURES
AND SCATTERED SNOW SHOWERS FOR FRIDAY AND THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
BLEND OF RECENT SATELLITE DATA, PLUS HRRR AND NAM MODEL OUTPUT,
SHOW THE ALTOCUMULUS WILL BE EXITING EAST PAST THE MOUNTAINS
OVERNIGHT. NAM MODEL PROFILES SHOW A STRONG SURFACE INVERSION
DEVELOPING LATE TONIGHT. HAVE NOT INCLUDED MENTION OF RIVER VALLEY
FOG PATCHES AS AIR TEMPERATURES, WITH LOWS AROUND 30, WILL NOT BE
COLD ENOUGH, MORE THAN 15 DEGREES DIFFERENCE FOR CONDENSATION, AS WATER
TEMPERATURES WILL BE NEAR 40.
NAM MODEL PROFILES SHOW CONSIDERABLE SUNSHINE TUESDAY AS NO MORE
THAN SCATTERED CLOUD COVERAGE EXPECTED.
MAINTAINED FORECAST OF TEMPERATURES, BASED ON BLEND OF RECENT GFS
AND NAM MOS AND HRRR MODEL OUTPUT, TO BE CLOSE TO 10 DEGREES
WARMER THAN NORMAL FOR THE PERIOD.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AFTER A DRY TUESDAY NIGHT, BLEND OF RECENT SREF MODEL OUTPUT
CONTINUES TO SHOW LOW PRESSURE, COMING NORTHEAST FROM LOUISIANA,
SPREADING RAIN NORTHEASTWARD ACROSS THE UPPER OHIO VALLEY
WEDNESDAY AND WEDNESDAY NIGHT.
ON THURSDAY, NORTHERN STREAM CLOSED LOW WILL DIVE INTO THE WESTERN
LAKES WHICH WILL PROPEL A COLD FRONT, ACCOMPANIED BY A BAND OF
RAIN SHOWERS, EASTWARD THROUGH THE UPPER OHIO VALLEY.
INFLOW OF WARMER AIR AHEAD OF THE LOW PRESSURE AND COLD FRONT WILL
MAINTAIN TEMPERATURES CLOSE TO 10 DEGREES WARMER THAN NORMAL THROUGH
THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONSENSUS OF ECMWF AND NAEFS MODEL OUTPUT SHOWS A COLD, CLOSED
UPPER LEVEL LOW PASSING EASTWARD THROUGH THE GREAT LAKES FRIDAY.
THIS WILL INDUCE A COLD WESTERLY LOW LEVEL FLOW ACROSS THE UPPER
OHIO VALLEY FOR FRIDAY INTO SATURDAY. AT THIS JUNCTURE, DOWN-LAKE
TRAJECTORIES ARE NOT ALL THAT FAVORABLE FOR A WIDESPREAD LAKE-
EFFECT SNOW SHOWER EVENT, BUT SHOULD FLOW SHOULD PROVIDE ENOUGH
MOISTURE AND INSTABILITY TO PROMOTE SCATTERED SNOW SHOWERS, AND
PERHAPS NUMEROUS SNOW SHOWERS AT TIMES ACROSS NORTHWESTERN PA AND
THE HIGHER MOUNTAINS.
FORECASTED TEMPERATURES, USING BLEND OF GFS MOS AND NAEFS MEDIAN
VALUES, TO BE NOTICEABLY COLDER THAN PREVIOUS DAYS, WITH
TEMPERATURES ABOUT 5 DEGREES COLDER THAN NORMAL FRIDAY AND
SATURDAY. TEMPERATURES MAY RECOVER TO NEAR NORMAL VALUES SUNDAY
AND MONDAY.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL PROVIDE VFR INTO TUESDAY NIGHT.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
LOW PRESSURE, MOVING NORTHEAST FROM THE TENNESSEE VALLEY TOWARD THE
MID-ATLANTIC, WILL PROVIDE RAIN WITH RESTRICTIONS LATE WEDNESDAY
INTO THURSDAY. TRAILING COLD FRONT WILL PROVIDE RAIN SHOWERS WITH
RESTRICTIONS THURSDAY. POST SYSTEM COLD WESTERLY FLOW WILL PRODUCE
SCATTERED SNOW SHOWERS WITH RESTRICTIONS THURSDAY NIGHT THROUGH
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
639 PM EST MON JAN 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY AND MILD CONDITIONS THROUGH
TUESDAY. LOW PRESSURE, COMING NORTHEAST FROM LOUISIANA, WILL BRING RAIN
TO THE UPPER OHIO VALLEY WEDNESDAY INTO WEDNESDAY NIGHT. A COLD
FRONTAL PASSAGE THURSDAY WILL BRING SHARPLY COLDER TEMPERATURES
AND SCATTERED SNOW SHOWERS FOR FRIDAY AND THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
BLEND OF RECENT SATELLITE DATA PLUS HRRR AND NAM MODEL OUTPUT,
SHOW ALTOCUMULUS ACROSS THE UPPER OHIO VALLEY, AND THE UPPER LEVEL
TROUGH CAUSING THESE CLOUDS, EXITING EAST LATE TONIGHT. HENCE
EXPECT DECREASING CLOUDS OVERNIGHT AND A GOOD BIT OF SUNSHINE
TUESDAY.
MAINTAINED FORECAST OF TEMPERATURES, BASED ON BLEND OF RECENT GFS
AND NAM MOS AND HRRR MODEL OUTPUT, TO BE CLOSE TO 10 DEGREES
WARMER THAN NORMAL FOR THE PERIOD.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AFTER A DRY TUESDAY NIGHT, BLEND OF RECENT SREF MODEL OUTPUT
CONTINUES TO SHOW LOW PRESSURE, COMING NORTHEAST FROM LOUISIANA,
SPREADING RAIN NORTHEASTWARD ACROSS THE UPPER OHIO VALLEY
WEDNESDAY AND WEDNESDAY NIGHT.
ON THURSDAY, NORTHERN STREAM CLOSED LOW WILL DIVE INTO THE WESTERN
LAKES WHICH WILL PROPEL A COLD FRONT, ACCOMPANIED BY A BAND OF
RAIN SHOWERS, EASTWARD THROUGH THE UPPER OHIO VALLEY.
INFLOW OF WARMER AIR AHEAD OF THE LOW PRESSURE AND COLD FRONT WILL
MAINTAIN TEMPERATURES CLOSE TO 10 DEGREES WARMER THAN NORMAL THROUGH
THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONSENSUS OF ECMWF AND NAEFS MODEL OUTPUT SHOWS A COLD, CLOSED
UPPER LEVEL LOW PASSING EASTWARD THROUGH THE GREAT LAKES FRIDAY.
THIS WILL INDUCE A COLD WESTERLY LOW LEVEL FLOW ACROSS THE UPPER
OHIO VALLEY FOR FRIDAY INTO SATURDAY. AT THIS JUNCTURE, DOWN-LAKE
TRAJECTORIES ARE NOT ALL THAT FAVORABLE FOR A WIDESPREAD LAKE-
EFFECT SNOW SHOWER EVENT, BUT SHOULD FLOW SHOULD PROVIDE ENOUGH
MOISTURE AND INSTABILITY TO PROMOTE SCATTERED SNOW SHOWERS, AND
PERHAPS NUMEROUS SNOW SHOWERS AT TIMES ACROSS NORTHWESTERN PA AND
THE HIGHER MOUNTAINS.
FORECASTED TEMPERATURES, USING BLEND OF GFS MOS AND NAEFS MEDIAN
VALUES, TO BE NOTICEABLY COLDER THAN PREVIOUS DAYS, WITH
TEMPERATURES ABOUT 5 DEGREES COLDER THAN NORMAL FRIDAY AND
SATURDAY. TEMPERATURES MAY RECOVER TO NEAR NORMAL VALUES SUNDAY
AND MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL THROUGHOUT THE TAF PERIOD WITH A SURFACE
HIGH BUILDING IN FROM THE SOUTHWEST ON TUESDAY.
SOUTHWESTERLY WINDS AROUND 5 KTS WILL PICK UP SLIGHTLY
OVERNIGHT...AND DROP OFF AT SUNSET ON TUESDAY.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
VFR CONDITIONS WILL PREVAIL INTO EARLY WEDNESDAY AS SURFACE HIGH
SHIFTS OFF THE MID-ATLANTIC COAST. LOW PRESSURE WILL THEN MOVE
FROM THE TENNESSEE VALLEY INTO THE MID-ATLANTIC, PUSHING RAIN WITH
RESTRICTIONS ACROSS THE TERMINALS LATE WEDNESDAY INTO THURSDAY.
SNOW SHOWERS WITH RESTRICTIONS ON THE BACK SIDE OF THE SYSTEM WILL
BE POSSIBLE FOR THURSDAY NIGHT THROUGH SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
316 PM EST SUN JAN 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE UPPER OHIO VALLEY AND ALLOW FOR
DRY AND MILD CONDITIONS THROUGH TUESDAY. A SURFACE LOW COMING FROM
THE SOUTHWEST WILL BRING RAIN TO THE AREA ON WEDNESDAY. MUCH
COLDER AIR IN THE WAKE OF THE LOW WILL BRING SNOW SHOWERS FOR THE
END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A ZONAL FLOW ACROSS THE
UPPER OHIO VALLEY WITH AN AREA OF MID-LEVEL MOISTURE UPSTREAM
MOVING INTO WESTERN OHIO. AT THE SURFACE, OBS/MSAS INDICATE A 1027MB
HIGH CENTERED ACROSS ILLINOIS. THIS BROAD AREA OF HIGH PRESSURE
EXTENDS FROM THE CENTRALS PLAINS ACROSS THE UPPER OHIO VALLEY AND
INTO THE MID-ATLANTIC. IN A NORTHWESTERLY FLOW, THE MOISTURE FEED
OFF OF LAKE ERIE IS PROVIDING STRATOCUMULUS CLOUD COVERAGE FOR
AREAS MOSTLY NORTH AND EAST OF PITTSBURGH.
TONIGHT...HIGH PRESSURE WILL SLIDE ACROSS THE AREA, ALLOWING FOR DRY
CONDITIONS TO CONTINUE. 850MB FLOW SHIFTING TO ZONAL WILL ALLOW
FOR DRIER LOW-LEVEL AIR TO PUSH ACROSS THE AREA. ALTHOUGH LOW-
LEVEL CLOUDS WILL DIMINISH ACROSS THE AREA WITH CLEARING BY THIS
EVENING, MID- LEVEL MOISTURE WILL THEN BEGIN TO ADVECT IN FROM THE
WEST. THUS, MOSTLY CLOUDY IS THE FORECAST OVERNIGHT. DESPITE TDS
IN THE LOW 20S AND HIGH PRESSURE OVERHEAD TONIGHT, MID-LEVEL CLOUD
COVERAGE WILL SERVE TO LIMIT RADIATIONAL COOLING. OVERNIGHT LOWS
WILL RANGE FROM THE LOWER 20S ACROSS THE EASTERN RIDGES TO THE
UPPER 20S SOUTH OF THE I-70 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THERE IS HIGH CONFIDENCE WITH OPERATIONAL MODEL AGREEMENT THAT AN
INITIAL SURFACE HIGH WILL SHIFT EAST OF THE AREA EARLY ON MONDAY.
THE DRY PATTERN WILL THEN BE REINFORCED BY ANOTHER HIGH BUILDING IN
FROM THE CENTRAL PLAINS. THIS WILL ALLOW FOR A RELATIVELY BENIGN AND
WARM SPELL TO CONTINUE FOR MONDAY AND TUESDAY. ASIDE FROM SOME
PASSING MID-LEVEL CLOUDS, MOSTLY SUNNY SKIES FOR THE MAJORITY CAN BE
EXPECTED THROUGH THIS PERIOD.
HIGH TEMPERATURES MONDAY AND TUESDAY ARE GENERALLY 2-4 DEGREES
WARMER THAN A MAV/MET BLEND. HIGHS ON MONDAY WILL RANGE FROM THE
THE LOWER 40S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES TO THE
LOWER 50S IN NORTH-CENTRAL WV AND PORTIONS OF EASTERN OHIO. WITH
WEAK WARM AIR ADVECTION, EXPECT TEMPS ON TUESDAY TO BE A COUPLE
DEGREES WARMER THAN MONDAY. OVERNIGHT LOWS WILL BE AROUND 5 TO 10
DEGREES ABOVE SEASONAL NORMALS.
WEDNESDAY...MODELS BEGIN TO DIFFER IN TIMING THE ONSET OF THE
NEXT RAIN EVENT. FORECAST IS CLOSEST TO THE SLIGHTLY FASTER GFS.
A CLOSED MID-LEVEL LOW ACROSS THE CENTRAL GULF STATES WILL MOVE
ACROSS THE TENNESSEE VALLEY. 12Z OPERATIONAL MODEL RUNS HAVE SLOWED
ONSET OF PRECIP ALTHOUGH FORECAST ONLY TRENDS THIS WAY SLIGHTLY TO
AVOID A DRASTIC CHANGE AT THIS POINT. FORECAST REFLECTS AN AREA OF
ISENTROPIC LIFT BRINGING SHOWERS TO THE AREA EARLY ON WEDNESDAY.
THUS, CHANCE POPS BEGIN AFTER 12Z WED AND RAMP UP TO LIKELY BY
WEDNESDAY AFTERNOON. WITH A WARM FRONT PUSHING NORTHWARD INTO THE
AREA, TEMPERATURES WILL BE AROUND 15 DEGREES ABOVE NORMAL,
REACHING THE 50S ACROSS MOST LOCATIONS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
RAIN WILL BE LIKELY ACROSS THE REGION WEDNESDAY NIGHT AS STRONG
SURFACE LOW MOVES ACROSS THE MID ATLANTIC STATES AND TO THE COAST BY
THURSDAY MORNING. ON THURSDAY QUITE STRONG NORTHERN BRANCH CLOSED
UPPER LOW DIGS ACROSS THE GREAT LAKES. THIS NORTHERN BRANCH LOW WILL
BRING MUCH COLDER AIR INTO REGION STARTING THURSDAY AFTERNOON AND
CONTINUING INTO THE WEEKEND. RAIN SHOWERS WILL MIX WITH AND CHANGE
TO SNOW THURSDAY FOLLOWED BY NORTHWEST FLOW SNOW SHOWERS INTO
SATURDAY. A RIDGE OF HIGH PRESSURE WILL BRING DRY AIR AND DIMINISH
SNOW SHOWERS SUNDAY. AFTER A MILD START WEDNESDAY NIGHT INTO EARLY
THURSDAY TEMPERATURES WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR INTO MONDAY WITH LEFTOVER STRATUS FROM LAKES ERODING THIS
EVENING TO BE REPLACED BY MID DECK APPROACHING FROM THE LOWER OHIO
VALLEY LATER TONIGHT. LIGHT NORTH WINDS THIS EVENING WILL TRANSITION
TO LIGHT SOUTH TO SOUTHWEST MONDAY.
OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...
VFR INTO EARLY WEDNESDAY. NORTHEASTBOUND LOW PRESSURE FROM LOUISIANA
WILL PROVIDE RESTRICTIONS IN RAIN LATER WEDNESDAY INTO EARLY
THURSDAY. RAIN SHOWERS WILL MIX AND CHANGE TO SNOW SHOWERS THURSDAY
WITH RESTRICTIONS IN SNOW SHOWERS THROUGH FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1255 PM EST SUN JAN 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE UPPER OHIO VALLEY AND ALLOW FOR
DRY AND MILD CONDITIONS THROUGH TUESDAY. A SURFACE LOW COMING FROM
THE SOUTHWEST WILL BRING RAIN TO THE AREA ON WEDNESDAY. MUCH
COLDER AIR IN THE WAKE OF THE LOW WILL BRING SNOW SHOWERS FOR THE
END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO TIME
THE DIMINISHING OF STRATOCUMULUS NORTH OF I-70 AND CLEARING IN
EASTERN OHIO. OTHERWISE, REST OF PREVIOUS DISCUSSION REMAINS THE
SAME.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A ZONAL FLOW ACROSS
THE UPPER OHIO VALLEY WITH AN AREA OF MID-LEVEL MOISTURE UPSTREAM
IN THE MISSOURI VALLEY. AT THE SURFACE, OBS/MSAS INDICATE A 1029MB
HIGH CENTERED ACROSS ILLINOIS. THIS BROAD AREA OF HIGH PRESSURE
EXTENDS FROM THE CENTRALS PLAINS ACROSS THE UPPER OHIO VALLEY AND
INTO THE MID-ATLANTIC. 12Z SOUNDING INDICATES SUBSIDENCE ABOVE
850MB WITH THE DRY WEATHER PATTERN CONTINUING. IN A NORTHWESTERLY
FLOW, MOISTURE FEED OFF OF LAKE ERIE IS PROVIDING STRATOCUMULUS
CLOUD COVERAGE THIS AFTERNOON.
THIS AFTERNOON AND TONIGHT...HIGH PRESSURE WILL SLIDE ACROSS THE
AREA, ALLOWING FOR DRY CONDITIONS TO CONTINUE. 850MB NORTHWESTERLY
FLOW WILL BRING MOSTLY CLOUDY SKIES TO AREAS NORTH AND EAST OF
PITTSBURGH. FLOW WILL BECOME ZONAL, WITH DRIER LOW-LEVEL AIR
ADVECTING INTO THE AREA. ALTHOUGH LOW-LEVEL CLOUDS WILL DIMINISH
ACROSS THE AREA BY THIS EVENING, BY THAT TIME, MID-LEVEL MOISTURE
WILL BEGIN TO ADVECT ACROSS THE AREA. THUS, MOSTLY CLOUDY IS THE
FORECAST OVERNIGHT.
FOR TEMPERATURES, HIGHS TODAY ARE A FEW DEGREES WARMER THAN LAMP
GUIDANCE. HIGHS WILL RANGE FROM THE MID 30S ALONG THE I-80
CORRIDOR TO THE MID 40S IN PORTIONS OF EASTERN OHIO AND NORTH-
CENTRAL WV. DESPITE TDS IN THE LOW 20S AND HIGH PRESSURE OVERHEAD
TONIGHT, MID-LEVEL CLOUD COVERAGE WILL SERVE TO LIMIT RADIATIONAL
COOLING. OVERNIGHT LOWS WILL RANGE FROM THE LOWER 20S ACROSS THE
EASTERN RIDGES TO UPPER 20S SOUTH OF THE I-70 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL PROVIDE DRY WEATHER AND MILD TEMPERATURES
THROUGH THIS PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A CLOSED MID-LEVEL LOW WILL MOVE FROM THE WESTERN GULF STATES ACROSS
THE TENNESSEE VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE CHANCE OF
RAIN WILL ARRIVE LATE TUESDAY NIGHT AS A WARM FRONT AHEAD OF THE LOW
PUSHES NORTHWARD INTO THE AREA. MODEL THICKNESSES WILL WARM ABOVE
CRITICAL THRESHOLDS THAT WOULD BE NEEDED FOR A WINTRY MIX, SO
FORECAST IS FOR ALL RAIN TO BEGIN THE EVENT. TEMPERATURES WILL BE
AROUND 10 DEGREES ABOVE NORMAL THROUGH THE MID-WEEK.
RAIN WILL BE LIKELY ACROSS THE REGION WEDNESDAY INTO WEDNESDAY NIGHT
AS THE LOW MOVES ACROSS WEST VIRGINIA AND INTO THE NORTHEAST. BY
THURSDAY MORNING LOW WILL BE EXITING EAST AS QUITE STRONG NORTHERN
BRANCH CLOSED UPPER LOW DIGS ACROSS THE GREAT LAKES. THIS NORTHERN
BRANCH LOW WILL BRING MUCH COLDER AIR INTO REGION STARTING THURSDAY
AND CONTINUING INTO THE START OF THE WEEKEND. RAIN SHOWERS WILL MIX
WITH AND CHANGE TO SNOW THURSDAY FOLLOWED BY NORTHWEST FLOW SNOW
SHOWERS INTO FRIDAY. BY SATURDAY A RIDGE OF HIGH PRESSURE WILL BRING
DRY AND COLD CONDITIONS. AS ALSO SUPPORTED BY NAEFS MEDIAN VALUES
TEMPERATURES WILL FALL TO 5 TO 10 DEGREES BELOW NORMAL LATE WEEK.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR REMAINDER OF DAY AS DECK OF BKN-OVC SC WILL CONTINUE TO SHIFT
EAST WITH MID-LEVEL COLD POOL. CLOUDS WILL ERODE BY LATE AFTERNOON
AS WAA BEGINS.
OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
VFR INTO TUESDAY NIGHT. NORTHEASTBOUND LOW PRESSURE FROM LOUISIANA
WILL PROVIDE MIXED PRECIPITATION AND RESTRICTIONS WEDNESDAY AND
THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1036 AM EST SUN JAN 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE UPPER OHIO VALLEY AND ALLOW FOR
DRY AND MILD CONDITIONS THROUGH TUESDAY. A SURFACE LOW COMING FROM
THE SOUTHWEST WILL BRING RAIN TO THE AREA ON WEDNESDAY. MUCH
COLDER AIR IN THE WAKE OF THE LOW WILL BRING SNOW SHOWERS FOR THE
END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO MAKE
SLIGHT ADJUSTMENTS TO SKY GRIDS. OTHERWISE, ONGOING FORECAST
REMAINS UNCHANGED.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A ZONAL FLOW ACROSS
THE UPPER OHIO VALLEY WITH AN AREA OF MID-LEVEL MOISTURE UPSTREAM
IN THE MISSOURI VALLEY. AT THE SURFACE, OBS/MSAS INDICATE A 1029MB
HIGH CENTERED ACROSS ILLINOIS. THIS BROAD AREA OF HIGH PRESSURE
EXTENDS FROM THE CENTRALS PLAINS ACROSS THE UPPER OHIO VALLEY AND
INTO THE MID-ATLANTIC. 12Z SOUNDING INDICATES SUBSIDENCE ABOVE
850MB WITH THE DRY WEATHER PATTERN CONTINUING. IN A NORTHWESTERLY
FLOW, MOISTURE FEED OFF OF LAKE ERIE IS PROVIDING STRATOCUMULUS
CLOUD COVERAGE THIS MORNING FOR AREAS MOSTLY NORTH AND EAST OF
PITTSBURGH.
THIS AFTERNOON AND TONIGHT...HIGH PRESSURE WILL SLIDE ACROSS THE
AREA, ALLOWING FOR DRY CONDITIONS TO CONTINUE. 850MB NORTHWESTERLY
FLOW WILL BRING MOSTLY CLOUDY SKIES TO AREAS NORTH AND EAST OF
PITTSBURGH. FLOW WILL BECOME ZONAL, WITH DRIER LOW-LEVEL AIR
ADVECTING INTO THE AREA. ALTHOUGH LOW-LEVEL CLOUDS WILL DIMINISH
ACROSS THE AREA BY THIS EVENING, BY THAT TIME, MID-LEVEL MOISTURE
WILL BEGIN TO ADVECT ACROSS THE AREA. THUS, MOSTLY CLOUDY IS THE
FORECAST OVERNIGHT.
FOR TEMPERATURES, HIGHS TODAY ARE A FEW DEGREES WARMER THAN LAMP
GUIDANCE. HIGHS WILL RANGE FROM THE MID 30S ALONG THE I-80
CORRIDOR TO THE MID 40S IN PORTIONS OF EASTERN OHIO AND NORTH-
CENTRAL WV. DESPITE TDS IN THE LOW 20S AND HIGH PRESSURE OVERHEAD
TONIGHT, MID-LEVEL CLOUD COVERAGE WILL SERVE TO LIMIT RADIATIONAL
COOLING. OVERNIGHT LOWS WILL RANGE FROM THE LOWER 20S ACROSS THE
EASTERN RIDGES TO UPPER 20S SOUTH OF THE I-70 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL PROVIDE DRY WEATHER AND MILD TEMPERATURES
THROUGH THIS PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A CLOSED MID-LEVEL LOW WILL MOVE FROM THE WESTERN GULF STATES ACROSS
THE TENNESSEE VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE CHANCE OF
RAIN WILL ARRIVE LATE TUESDAY NIGHT AS A WARM FRONT AHEAD OF THE LOW
PUSHES NORTHWARD INTO THE AREA. MODEL THICKNESSES WILL WARM ABOVE
CRITICAL THRESHOLDS THAT WOULD BE NEEDED FOR A WINTRY MIX, SO
FORECAST IS FOR ALL RAIN TO BEGIN THE EVENT. TEMPERATURES WILL BE
AROUND 10 DEGREES ABOVE NORMAL THROUGH THE MID-WEEK.
RAIN WILL BE LIKELY ACROSS THE REGION WEDNESDAY INTO WEDNESDAY NIGHT
AS THE LOW MOVES ACROSS WEST VIRGINIA AND INTO THE NORTHEAST. BY
THURSDAY MORNING LOW WILL BE EXITING EAST AS QUITE STRONG NORTHERN
BRANCH CLOSED UPPER LOW DIGS ACROSS THE GREAT LAKES. THIS NORTHERN
BRANCH LOW WILL BRING MUCH COLDER AIR INTO REGION STARTING THURSDAY
AND CONTINUING INTO THE START OF THE WEEKEND. RAIN SHOWERS WILL MIX
WITH AND CHANGE TO SNOW THURSDAY FOLLOWED BY NORTHWEST FLOW SNOW
SHOWERS INTO FRIDAY. BY SATURDAY A RIDGE OF HIGH PRESSURE WILL BRING
DRY AND COLD CONDITIONS. AS ALSO SUPPORTED BY NAEFS MEDIAN VALUES
TEMPERATURES WILL FALL TO 5 TO 10 DEGREES BELOW NORMAL LATE WEEK.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
VFR REMAINDER OF DAY AS DECK OF BKN-OVC SC WILL CONTINUE TO SHIFT
EAST WITH MID-LEVEL COLD POOL. CLOUDS WILL ERODE BY LATE AFTERNOON
AS WAA BEGINS.
OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
VFR INTO TUESDAY NIGHT. NORTHEASTBOUND LOW PRESSURE FROM LOUISIANA
WILL PROVIDE MIXED PRECIPITATION AND RESTRICTIONS WEDNESDAY AND
THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1051 PM EST MON JAN 9 2012
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL RIDGE
FROM CA INTO ALBERTA/SASK AND A TROUGH INTO HUDSON BAY RESULTING IN
NW FLOW DONWSTREAM INTO THE WESTERN GREAT LAKES. DRY AND WARMER AIR
HAS MOVED INTO THE CWA BEHIND A MID LEVEL SHORTWAVE AND SFC TROUGH
THAT BROUGHT LIGHT SNOW TO ERN UPPER MI THIS MORNING. THE TIGHT
GRADIENT IN THE WAKE OF THE TROUGH WITH WRLY WINDS INTO THE KEWEENAW
HAS BROUGHT BLUSTERY WINDS TO THE KEWEENAW WITH SOME GUSTS IN THE 35
TO 45 MPH RANGE. THE VIS SATELLITE LOOP SHOWED MAINLY CLEAR SKIES
OVER THE AREA WHICH HAS ALLOWED TEMPS TO CLIMB INTO THE LOWER TO MID
40S OVER THE WEST HALF OF THE AREA
&&
.SHORT TERM...TONIGHT AND TUESDAY
EXPECT THAT THE WINDS WILL DIMINISH QUICKLY LATE THIS AFTERNOON AND
EVENING AS A SFC RIDGE BUILDS INTO THE AREA. SATELLITE TRENDS AND
NAM SFC-850 MB RH PROGS SUGGEST THAT LOWER LEVEL MOISTURE OVER FAR
NE MN AND NRN LAKE SUPERIOR WILL GENERALLY MOVE OFF TO THE EAST.
WITH THE THE LIGHTER WINDS AND MAINLY CLEAR SKIES SHOULD ALLOW TEMPS
TO DROP AT OR BLO DEWPOINTS...INTO THE LOWER TO MID 20S. ALTHOUGH
MID/HIGH CLOUDS MAY INCREASE WITH THE DEVELOPING WAA PATTERN...THERE
SHOULD BE ENOUGH INSOLATION TO PUSH TEMPS WELL ABOVE NORMAL.
SO...CONTINUED TO KEEP FCST MAX READINGS SEVERAL DEGREES ABOVE
SOMEWHAT CLIMATOLOGY WEIGHTED GUIDANCE...INTO THE UPPER 30S TO MID
40S.
.LONG TERM (TUE NIGHT THROUGH MONDAY)...
MAIN FORECAST CONCERNS FOR MID WEEK REVOLVE AROUND THE POTENTIAL FOR
HEAVY LAKE ENHANCED SNOW NEAR LAKE SUPERIOR.
MODEL GUIDANCE BEGINS TO DIVERGE RATHER QUICKLY TUESDAY EVENING INTO
WEDNESDAY REGARDING THE EVOLUTION OF THE CLOSED LOW MOVING OVER THE
UPPER GREAT LAKES. THE NAM SEEMS TO BE THE OUTLIER WITH THE SOLUTION
BEING PROGRESSIVE AND LESS AMPLIFIED COMPARED TO THE GFS...ECMWF AND
GEM SOLUTIONS WHICH ARE MORE AMPLIFIED AND MUCH SLOWER ESPECIALLY BY
THU. HOWEVER...EVEN AMONG THOSE THREE SOLUTIONS...THERE REMAINS
SUBTLE DIFFERENCES IN THE MASS FIELDS WHICH WILL PLAY AN IMPORTANT
ROLE WHERE THE HEAVIEST SNOW FALLS WED NIGHT INTO FRIDAY. ALL THREE
OF THE MODELS CLOSE OFF THE LOW AND SLOW IT DOWN OVER THE UPPER
GREAT LAKES. HOWEVER...THE ECMWF AND THE GEM TEND TO BE THE MOST
AMPLIFIED AND FURTHEST SOUTH COMPARED TO THE GFS. WITH THAT BEING
SAID...HAVE GENERALLY OPTED TO FOLLOW A ECMWF/GEM BLEND THROUGH THE
PERIOD.
ON TUESDAY NIGHT...EXPECT THE SURFACE LOW TO MOVE FROM THE CANADIAN
PRAIRIES TO WESTERN UPPER MICHIGAN BY WED MORNING. WILL BE TOUGH FOR
ANY PCPN TO FALL TUE NIGHT AHEAD OF THE SYSTEM WITH SYSTEM BEING OF
PACIFIC ORIGIN AND THE BEST MOISTURE BEING ROBBED BY THE SOUTHERN
STREAM SYSTEM OVER THE OHIO VALLEY. SOUTH-SOUTHWEST LOW LEVEL FLOW
WILL AHEAD OF THE SYSTEM WILL ALLOW FOR MILD TEMPS TUE NIGHT WITH
STRATUS POSSIBLE AS LOW LEVEL DEW POINTS INCREASE. HOWEVER...WITH
THE VERY DRY AIRMASS ALOFT ANY PCPN WILL NOT DEVELOP UNTIL WEDNESDAY
BEHIND THE LOW. THE LOW LEVEL STRATUS MAY SERVE AS A CATALYST FOR
DRIZZLE OR FREEZING DRIZZLE...AND IN FACT THE MODEL PROFILES FROM
THE NAM SUGGEST ESPECIALLY IN NORTH CENTRAL UPPER MICHIGAN THIS IS
POSSIBLE. HOWEVER...THE GFS IS NOT AS AGGRESSIVE IN THE LOW LEVEL
MOISTURE SO HAVE OPTED TO KEEP THIS OUT OF THE FORECAST FOR NOW.
THE ECMWF SHOWS THE LOW SLOWLY PASSING OVER OR JUST TO THE SOUTH OF
THE AREA ON WEDNESDAY AS THE UPPER LOW DIGS INTO THE NORTHERN MS
VLY. AS THE LOW MOVES EAST...COLDER AIR ALOFT MOVES ACROSS THE AREA.
SINCE MOST OF THE MOISTURE WILL LIKELY BE ASSOCIATED WITH THE
DEFORMATION AXIS TO THE NORTH AND WEST OF THE LOW...AND GIVEN THE
LOW WET BULB ZERO LEVELS...THE EXPECTATION IS THAT ANY PCPN WILL
FALL AS SNOW STARTING LATE WED MORNING ACROSS THE WEST THEN
EXPANDING EAST BY WED EVENING. LAKE EFFECT/ENHANCED SNOW WILL ALSO
DEVELOP ACROSS WESTERN UPPER MICHIGAN WED AFTN IN RESPONSE TO THE
NORTHWEST FLOW AND COLDER TEMPS ALOFT. WITH THIS BEING SAID...HAVE
OPTED TO MAINTAIN LIKELY POPS ACROSS THE WEST AND CHANCE POPS EAST.
DUE TO THE SOUTH FLOW NEAR LAKE MICHIGAN AND WARMER TEMPS
ALOFT...WILL KEEP A MENTION OF RAIN NEAR LAKE MICHIGAN THROUGH WED
EVENING BEFORE THE COLDER AIR ARRIVES.
LES WILL INCREASE IN COVERAGE AND INTENSITY WED NIGHT AND ESPECIALLY
ON THURSDAY DOWNWIND OF LAKE SUPERIOR. STILL SOME UNCERTAINTY OF THE
EXACT PLACEMENT OF THE HEAVIEST LES...BUT THE ECMWF AND THE GEM
WOULD IMPLY A MORE NORTHERLY BOUNDARY LAYER FLOW WHICH WOULD BRING
HEAVY SNOW INTO MUCH OF NORTHERN UPPER MICHIGAN. IN FACT...IF THE
ECMWF VERIFIES...THE FLOW THROUGH 700MB WILL BECOME NNE AS THE UPPER
LOW ROTATES INTO LOWER MICHIGAN ON THURSDAY INTO THU NIGHT WHILE THE
SFC LOW DEEPENS. THIS TYPE OF SCENARIO WOULD IMPLY A SIGNIFICANT
SNOWFALL FOR THE HIGHLANDS OF MARQUETTE COUNTY AS WELL...ESPECIALLY
SINCE THE ECMWF SUGGESTS SYNOPTIC SUPPORT WITH THE UPPER TROUGH
OVERHEAD. WILL CONTINUE WITH CATEGORICAL OR HIGH LIKELY POPS FOR
ALL AREAS IMMEDIATELY DOWNWIND OF LAKE SUPERIOR THU INTO THU NIGHT.
THE LOW FINALLY STARTS TO MOVE EAST ON FRIDAY ALLOWING ANY REMAINING
LES TO DIMINISH BY EVENING. QUIET WEATHER ON SATURDAY AS WEAK HIGH
PRESSURE RIDGE BUILDS ACROSS THE REGION BEFORE AN ALBERTA CLIPPER
TYPE SYSTEM ARRIVES SUNDAY. BEST MOISTURE REMAINS NORTH OF THE AREA
AND HAVE OPTED TO CONFINE LOW CHANCE POPS TO NEAR LAKE SUPERIOR.
TEMPS WILL REMAIN WELL ABOVE NORMAL TUE NIGHT INTO WED BEFORE
FALLING 10-20 DEGREES ON THURSDAY. ALTHOUGH THE BEST COLD AIR MAY
STAY WEST OF THE AREA...TEMPS WILL STILL STRUGGLE TO RISE MUCH ON
THURSDAY. WILL GO WITH TEMPS IN THE TEENS WEST AND MID 20S EAST.
CONTINUED COLD ON FRIDAY BEFORE SOME SLIGHT WARMING FOR THE WEEKEND
INTO MONDAY. HOWEVER...TEMPERATURES WILL REMAIN AT OR SLIGHTLY BELOW
NORMAL.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
A SWATH OF LOW CLOUD COVER STRETCHING FROM EASTERN MANITOBA INTO
UPPER MI WILL BE THE MAIN CONCERN FOR THIS TAF PERIOD. MODELS STILL
DO NOT HAVE A HANDLE ON THE CLOUD COVER...INSTEAD ALL GUIDANCE HAS
SKIES CLEAR AND REMAINING VFR THROUGHOUT THE PERIOD. CLOUD COVER ON
VISIBLE SATELLITE SHOWS OTHERWISE...AND SO LONG AS THE LOW LEVEL
MOISTURE IS PRESENT IT DOES NOT LOOK AS THOUGH IT WILL BE
DISSIPATING ANY TIME SOON AND WILL GO WITH PERSISTENCE. AS A
RESULT...HAVE KEPT VFR CIGS TO START OUT WITH AT ALL TAF
SITES...WITH SOME IMPROVEMENT POSSIBLE TUE MORNING. CONFIDENCE IS
LOW IN THIS FORECAST BECAUSE OF MODELS NOT HANDLING THE CLOUDS WELL
AND NOT SURE EXACTLY WHEN THESE WILL BREAK UP AS ALL 3 SITES ARE ON
THE SOUTHWESTERN EDGE OF THE LOW CLOUDS.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
GALE FORCE WEST WINDS OVER THE EAST HALF OF THE LAKE WILL DIMINISH
BY THIS EVENING AS HIGH PRESSURE BUILDS TOWARD THE REGION AND THE
GRADIENT WEAKENS. WINDS WILL DIMINISH BLO 20 KTS BY TUESDAY MORNING
WITH A WEAKENING PRESSURE GRADIENT...BUT WILL INCREASE OUT OF THE
N-NW WEDNESDAY AFTERNOON INTO FRIDAY AS MUCH COLDER SPREADS ACROSS
THE REGION AND THE PRES GRADIENT TIGHTENS IN THE WAKE OF A DEEPENING
LOW PRESSURE SYSTEM TO OUR EAST. NRLY WINDS SHOULD REACH GALE GALE
FORCE THU INTO FRI WITH MODERATE TO HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...MRD
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
635 PM EST MON JAN 9 2012
UPDATED AVIATION DISCUSSION FOR 00Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL RIDGE
FROM CA INTO ALBERTA/SASK AND A TROUGH INTO HUDSON BAY RESULTING IN
NW FLOW DONWSTREAM INTO THE WESTERN GREAT LAKES. DRY AND WARMER AIR
HAS MOVED INTO THE CWA BEHIND A MID LEVEL SHORTWAVE AND SFC TROUGH
THAT BROUGHT LIGHT SNOW TO ERN UPPER MI THIS MORNING. THE TIGHT
GRADIENT IN THE WAKE OF THE TROUGH WITH WRLY WINDS INTO THE KEWEENAW
HAS BROUGHT BLUSTERY WINDS TO THE KEWEENAW WITH SOME GUSTS IN THE 35
TO 45 MPH RANGE. THE VIS SATELLITE LOOP SHOWED MAINLY CLEAR SKIES
OVER THE AREA WHICH HAS ALLOWED TEMPS TO CLIMB INTO THE LOWER TO MID
40S OVER THE WEST HALF OF THE AREA
&&
.SHORT TERM...TONIGHT AND TUESDAY
EXPECT THAT THE WINDS WILL DIMINISH QUICKLY LATE THIS AFTERNOON AND
EVENING AS A SFC RIDGE BUILDS INTO THE AREA. SATELLITE TRENDS AND
NAM SFC-850 MB RH PROGS SUGGEST THAT LOWER LEVEL MOISTURE OVER FAR
NE MN AND NRN LAKE SUPERIOR WILL GENERALLY MOVE OFF TO THE EAST.
WITH THE THE LIGHTER WINDS AND MAINLY CLEAR SKIES SHOULD ALLOW TEMPS
TO DROP AT OR BLO DEWPOINTS...INTO THE LOWER TO MID 20S. ALTHOUGH
MID/HIGH CLOUDS MAY INCREASE WITH THE DEVELOPING WAA PATTERN...THERE
SHOULD BE ENOUGH INSOLATION TO PUSH TEMPS WELL ABOVE NORMAL.
SO...CONTINUED TO KEEP FCST MAX READINGS SEVERAL DEGREES ABOVE
SOMEWHAT CLIMATOLOGY WEIGHTED GUIDANCE...INTO THE UPPER 30S TO MID
40S.
.LONG TERM (TUE NIGHT THROUGH MONDAY)...
MAIN FORECAST CONCERNS FOR MID WEEK REVOLVE AROUND THE POTENTIAL FOR
HEAVY LAKE ENHANCED SNOW NEAR LAKE SUPERIOR.
MODEL GUIDANCE BEGINS TO DIVERGE RATHER QUICKLY TUESDAY EVENING INTO
WEDNESDAY REGARDING THE EVOLUTION OF THE CLOSED LOW MOVING OVER THE
UPPER GREAT LAKES. THE NAM SEEMS TO BE THE OUTLIER WITH THE SOLUTION
BEING PROGRESSIVE AND LESS AMPLIFIED COMPARED TO THE GFS...ECMWF AND
GEM SOLUTIONS WHICH ARE MORE AMPLIFIED AND MUCH SLOWER ESPECIALLY BY
THU. HOWEVER...EVEN AMONG THOSE THREE SOLUTIONS...THERE REMAINS
SUBTLE DIFFERENCES IN THE MASS FIELDS WHICH WILL PLAY AN IMPORTANT
ROLE WHERE THE HEAVIEST SNOW FALLS WED NIGHT INTO FRIDAY. ALL THREE
OF THE MODELS CLOSE OFF THE LOW AND SLOW IT DOWN OVER THE UPPER
GREAT LAKES. HOWEVER...THE ECMWF AND THE GEM TEND TO BE THE MOST
AMPLIFIED AND FURTHEST SOUTH COMPARED TO THE GFS. WITH THAT BEING
SAID...HAVE GENERALLY OPTED TO FOLLOW A ECMWF/GEM BLEND THROUGH THE
PERIOD.
ON TUESDAY NIGHT...EXPECT THE SURFACE LOW TO MOVE FROM THE CANADIAN
PRAIRIES TO WESTERN UPPER MICHIGAN BY WED MORNING. WILL BE TOUGH FOR
ANY PCPN TO FALL TUE NIGHT AHEAD OF THE SYSTEM WITH SYSTEM BEING OF
PACIFIC ORIGIN AND THE BEST MOISTURE BEING ROBBED BY THE SOUTHERN
STREAM SYSTEM OVER THE OHIO VALLEY. SOUTH-SOUTHWEST LOW LEVEL FLOW
WILL AHEAD OF THE SYSTEM WILL ALLOW FOR MILD TEMPS TUE NIGHT WITH
STRATUS POSSIBLE AS LOW LEVEL DEW POINTS INCREASE. HOWEVER...WITH
THE VERY DRY AIRMASS ALOFT ANY PCPN WILL NOT DEVELOP UNTIL WEDNESDAY
BEHIND THE LOW. THE LOW LEVEL STRATUS MAY SERVE AS A CATALYST FOR
DRIZZLE OR FREEZING DRIZZLE...AND IN FACT THE MODEL PROFILES FROM
THE NAM SUGGEST ESPECIALLY IN NORTH CENTRAL UPPER MICHIGAN THIS IS
POSSIBLE. HOWEVER...THE GFS IS NOT AS AGGRESSIVE IN THE LOW LEVEL
MOISTURE SO HAVE OPTED TO KEEP THIS OUT OF THE FORECAST FOR NOW.
THE ECMWF SHOWS THE LOW SLOWLY PASSING OVER OR JUST TO THE SOUTH OF
THE AREA ON WEDNESDAY AS THE UPPER LOW DIGS INTO THE NORTHERN MS
VLY. AS THE LOW MOVES EAST...COLDER AIR ALOFT MOVES ACROSS THE AREA.
SINCE MOST OF THE MOISTURE WILL LIKELY BE ASSOCIATED WITH THE
DEFORMATION AXIS TO THE NORTH AND WEST OF THE LOW...AND GIVEN THE
LOW WET BULB ZERO LEVELS...THE EXPECTATION IS THAT ANY PCPN WILL
FALL AS SNOW STARTING LATE WED MORNING ACROSS THE WEST THEN
EXPANDING EAST BY WED EVENING. LAKE EFFECT/ENHANCED SNOW WILL ALSO
DEVELOP ACROSS WESTERN UPPER MICHIGAN WED AFTN IN RESPONSE TO THE
NORTHWEST FLOW AND COLDER TEMPS ALOFT. WITH THIS BEING SAID...HAVE
OPTED TO MAINTAIN LIKELY POPS ACROSS THE WEST AND CHANCE POPS EAST.
DUE TO THE SOUTH FLOW NEAR LAKE MICHIGAN AND WARMER TEMPS
ALOFT...WILL KEEP A MENTION OF RAIN NEAR LAKE MICHIGAN THROUGH WED
EVENING BEFORE THE COLDER AIR ARRIVES.
LES WILL INCREASE IN COVERAGE AND INTENSITY WED NIGHT AND ESPECIALLY
ON THURSDAY DOWNWIND OF LAKE SUPERIOR. STILL SOME UNCERTAINTY OF THE
EXACT PLACEMENT OF THE HEAVIEST LES...BUT THE ECMWF AND THE GEM
WOULD IMPLY A MORE NORTHERLY BOUNDARY LAYER FLOW WHICH WOULD BRING
HEAVY SNOW INTO MUCH OF NORTHERN UPPER MICHIGAN. IN FACT...IF THE
ECMWF VERIFIES...THE FLOW THROUGH 700MB WILL BECOME NNE AS THE UPPER
LOW ROTATES INTO LOWER MICHIGAN ON THURSDAY INTO THU NIGHT WHILE THE
SFC LOW DEEPENS. THIS TYPE OF SCENARIO WOULD IMPLY A SIGNIFICANT
SNOWFALL FOR THE HIGHLANDS OF MARQUETTE COUNTY AS WELL...ESPECIALLY
SINCE THE ECMWF SUGGESTS SYNOPTIC SUPPORT WITH THE UPPER TROUGH
OVERHEAD. WILL CONTINUE WITH CATEGORICAL OR HIGH LIKELY POPS FOR
ALL AREAS IMMEDIATELY DOWNWIND OF LAKE SUPERIOR THU INTO THU NIGHT.
THE LOW FINALLY STARTS TO MOVE EAST ON FRIDAY ALLOWING ANY REMAINING
LES TO DIMINISH BY EVENING. QUIET WEATHER ON SATURDAY AS WEAK HIGH
PRESSURE RIDGE BUILDS ACROSS THE REGION BEFORE AN ALBERTA CLIPPER
TYPE SYSTEM ARRIVES SUNDAY. BEST MOISTURE REMAINS NORTH OF THE AREA
AND HAVE OPTED TO CONFINE LOW CHANCE POPS TO NEAR LAKE SUPERIOR.
TEMPS WILL REMAIN WELL ABOVE NORMAL TUE NIGHT INTO WED BEFORE
FALLING 10-20 DEGREES ON THURSDAY. ALTHOUGH THE BEST COLD AIR MAY
STAY WEST OF THE AREA...TEMPS WILL STILL STRUGGLE TO RISE MUCH ON
THURSDAY. WILL GO WITH TEMPS IN THE TEENS WEST AND MID 20S EAST.
CONTINUED COLD ON FRIDAY BEFORE SOME SLIGHT WARMING FOR THE WEEKEND
INTO MONDAY. HOWEVER...TEMPERATURES WILL REMAIN AT OR SLIGHTLY BELOW
NORMAL.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/...
A SWATH OF LOW CLOUD COVER STRETCHING FROM EASTERN MANITOBA AND DOWN
INTO UPPER MI WILL BE THE MAIN CONCERN FOR THIS TAF PERIOD. MODELS
DO NOT HAVE HANDLE ON CLOUD COVER...INSTEAD ALL GUIDANCE HAS SKIES
CLEAR AND REMAINING VFR THROUGHOUT THE PERIOD. CLOUD COVER ON
VISIBLE SATELLITE SHOWS OTHERWISE...AND SO LONG AS THE LOW LEVEL
MOISTURE IS PRESENT IT DOES NOT LOOK AS THOUGH IT WILL BE
DISSIPATING ANY TIME SOON. AS A RESULT HAVE KEPT MVFR CEILINGS TO
START OUT WITH AT ALL TAF SITES...WITH SOME IMPROVEMENT POSSIBLE BY
EARLY MORNING. MAY NEED TO AMEND IF NEW MODEL DATA SHOWS IMPROVEMENT
ON HANDLING THE CLOUD COVER FOR LATER IN TAF PERIOD.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
GALE FORCE WEST WINDS OVER THE EAST HALF OF THE LAKE WILL DIMINISH
BY THIS EVENING AS HIGH PRESSURE BUILDS TOWARD THE REGION AND THE
GRADIENT WEAKENS. WINDS WILL DIMINISH BLO 20 KTS BY TUESDAY MORNING
WITH A WEAKENING PRESSURE GRADIENT...BUT WILL INCREASE OUT OF THE
N-NW WEDNESDAY AFTERNOON INTO FRIDAY AS MUCH COLDER SPREADS ACROSS
THE REGION AND THE PRES GRADIENT TIGHTENS IN THE WAKE OF A DEEPENING
LOW PRESSURE SYSTEM TO OUR EAST. NRLY WINDS SHOULD REACH GALE GALE
FORCE THU INTO FRI WITH MODERATE TO HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265>267.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...MRD
AVIATION...JMW
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
354 PM EST SUN JAN 8 2012
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED MID/UPPER LEVEL RIDGE OVER THE
WEST COAST INTO BC/ALBERTA LEAVING WNW FLOW DOWNSTREAM THROUGH SRN
CANADA INTO THE NRN GREAT LAKES. A WEAK SHORTWAVE TROUGH FROM NEAR
THE SW END OF HUDSON BAY TO LAKE SUPERIOR THAT SUPPORTED BAND OF
SNOW SHOWERS ACROSS LAKE SUPERIOR AND NRN UPPER MI WAS EXITING TO
THE EAST. THE NEXT SIGNIFICANT SHRTWV WAS LOCATED OVER NRN MANITOBA.
AT THE SFC...WINDS WERE BACKING W AND SW AS A RIDGE BUILDS TOWARD
THE AREA. THE VIS SATELLITE LOOP SHOWED CLEARING OVER THE SW HALF OF
THE CWA AS DRIER AIR IN THE SFC-850 MB LAYER MOVES IN FROM THE
WEST.
&&
.SHORT TERM...TONIGHT AND MONDAY
THE NRN MANITOBA SHRTWV IS EXPECTED TO DIVE SOUTHEASTWARD TOWARD THE
UPPER GREAT LAKES. A BAND OF MODERATE 700-300 QVECTOR CONV WILL
SPREAD ACROSS THE AREA ALONG WITH A BAND OF FAIRLY STRONG 285K-290K
ISENTROPIC ASCENT FROM 09Z-15Z. HOWEVER...WITH LITTLE MOISTURE
AVBL...THE SFC-850 MB LAYER REMAINS RELATIVELY DRY. THE PATH OF THE
SHRTWV AND MODELS CONSENSUS STRONGEST FORCING AND QPF SUGGEST THAT
THE NORTH AND EAST PORTIONS OF THE CWA HAVE THE BEST CHANCE OF
SEEING SOME LIGHT SNOW. HOWEVER...ANY AMOUNTS ARE EXPECTED TO BE
LIGHT...GENERALLY A HALF INCH OR LESS. LEFTOVER CLOUDS INTO THE
EARLY AFTERNOON MAY DELAY WARMING ENOUGH TO KEEP TEMPS MAINLY
IN THE MID TO UPPER 30S...ESPECIALLY OVER THE EAST.
.LONG TERM /00Z TUE THROUGH NEXT SUN/...
EXPECT WARMER CONDITIONS MONDAY NIGHT AND TUESDAY AS THE UPPER GREAT
LAKES REMAINS IN WARM SECTOR OF LOW PRESSURE SYSTEM SLIDING FROM
MANITOBA INTO ONTARIO. BROKEN MID CLOUDS SHOULD BE AROUND LATE
MONDAY NIGHT INTO TUESDAY MORNING...BUT SOME SUNSHINE SHOULD APPEAR
BY AFTERNOON. GIVEN THE SUNSHINE AND SW WINDS AT THE SFC...TUESDAY
COULD BE ANOTHER DAY WITH NEAR RECORD OR RECORD WARMTH. MIXING TO
950-925MB SUPPORTS HIGHS AOA 40 DEGREES FOR MANY AREAS. KEPT THE
TREND FROM THE PREVIOUS SHIFT TOWARD HIGH END OF BIAS CORRECTED
GUIDANCE WHICH RESULTED IN MAX TEMPS IN MID TO UPPER 40S TOWARD WI
BORDER WHERE SNOW COVER REMAINS PRETTY THIN. RECORD HIGH AT NWS
MARQUETTE FOR TUESDAY IS 42 SET IN 2001. THIS IS EXPECTED TO BE THE
LAST WARMER DAY AT LEAST THROUGH NEXT WEEKEND AS PATTERN BEGINS TO
CHANGE ON WEDNESDAY.
WED THROUGH FRI...MODEL AGREEMENT HAS IMPROVED SINCE YESTERDAY WITH
A STRONG LOW PRESSURE SYSTEM THAT IS SET TO MOVE OVER THE AREA WED
THROUGH FRI. COMPARING THE 12Z/08 GFS...00Z/08 ECMWF...AND
12Z/08 GEM SOLUTIONS...THE GEM IS MORE OF AN OUTLIER SO IT WAS RULED
OUT FOR THIS FORECAST. BOTH THE GFS AND ECMWF BRING A 500MB TROUGH
FROM A CLOSED LOW FROM OVER AK...SHOWING A LOW CLOSING OFF FROM THE
TIP OF THE TROUGH AS IT MOVES INTO THE PACIFIC NW. MODELS THEN
DEPICT THE TROUGH MOVING TOWARD THE CWA BEFORE DEEPENING JUST
UPSTREAM OF THE CWA IN RESPONSE TO JET INTERACTION. THE GFS DEEPENS
THE UPPER TROUGH INTO A CLOSED LOW FASTER THAN THE ECWMF...AND IS
MORE TRANSIENT WITH THE SYSTEM AS IT MOVES S OF THE CWA. THE ECMWF
KEEP AN OPEN WAVE ALOFT UNTIL IT MOVES INTO WI AROUND 00Z FRI...AND
IS ABOUT 12 HOURS SLOWER WITH MOVING THE SYSTEM OUT THAN THE GFS.
THERE IS STILL FAIR POTENTIAL THAT MODELS ARE NOT SETTLED WITH THEIR
SOLUTIONS YET. A BIG REASON MODELS DIVERGE WITH THE TRACK AND
INTENSITY OF THE SYSTEM STARTS BACK WHEN THE TROUGH IS MOVING INTO
THE PACIFIC NW. A LOT WILL DEPEND OF WHAT MODELS DO WITH THE LOW
THAT IS SHOWN BREAKING OFF OF THE TROUGH. MODELS CURRENTLY AGREE
PRETTY WELL THAT THE LOW WILL STAY OFF THE CA COAST FOR A WHILE. IF
THE LOW MOVES FARTHER EAST FASTER...OR DEVELOPS FARTHER EAST...IT
WILL CUTS OFF SOME ACCESS TO COMPONENTS OF BOTH THE NRN AND SRN
STREAM JETS...CAUSING THE MAIN SYSTEM NOT TO STRENGTHEN AS MUCH AND
PROBABLY STAY FARTHER N. HOWEVER...EVEN IF THIS HAPPENS...850MB
TEMPS SHOULD STILL FALL TO AROUND -20C OVER LAKE SUPERIOR. WITH THE
SFC LOW DEEPENING OVER THE LOWER GREAT LAKES...NW BOUNDARY LAYER
WINDS LOOK TO BE THE WAY TO GO...AND THIS IS AGREED UPON WELL BY
MODELS. LIKELY POPS ARE WELL JUSTIFIED AT THIS POINT IN AREAS
FAVORED BY NW FLOW OFF LAKE SUPERIOR. CURRENTLY MODEL CONSENSUS
WOULD ALSO LEAD TO SYNOPTIC SNOW OVER THE REST OF UPPER MI...BUT
THIS IS A LITTLE MORE UNCERTAIN DUE TO UNCERTAINTY IN THE EXACT
TRACK OF THE UPPER LOW. WILL CONTINUE TO HIGHLIGHT THIS POTENTIAL
HEAVY SNOW IN THE HAZARDOUS WEATHER OUTLOOK.
SAT AND SUN...DID NOT DWELL TOO MUCH ON THIS PERIOD DUE TO
INCREASING MODEL VARIABILITY...BUT MODELS CURRENTLY SHOW SLIGHTLY
WARMER 850MB TEMPS STILL COLD ENOUGH FOR LES WITH A GENERALLY NW
WIND...AND A COUPLE OF SHORTWAVES MOVING THROUGH. THIS WOULD LEAD TO
PERIODS OF LES AND SLIGHTLY WARMER...BUT NEAR SEASONAL...TEMPS.
STAYED WITH CONSENSUS MODEL BLEND GIVEN UNCERTAINTY.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
AS A WEAK TROUGH EXITS THE AREA AND HIGH PRES BUILDS TOWARD THE
AREA...EXPECT REMAINING MVFR CIGS AT KCMX TO LIFT BY MID AFTERNOON.
EXPECT VFR CONDITIONS FOR THE REST OF THE FCST PERIOD. LOW LVL WIND
SHEAR WILL DEVELOP LATER THIS EVENING AND OVERNIGHT AS SW GRAD
TIGHTENS AHEAD OF LOW PRESSURE SYSTEM MOVING ACROSS NRN ONTARIO AS A
LOW-LVL WIND MAX MOVES ACROSS THE AREA. BY MON MORNING...GUSTY
SOUTHWEST TO WEST SOUTHWEST ARE EXPECTED.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
LOW PRESSURE IS FORECAST TO MOVE FROM ALBERTA TO JAMES BAY BY
MONDAY. STRONG PRESSURE FALLS NORTH OF LAKE SUPERIOR AND AN
INCREASING PRESSURE GRADIENT IS EXPECTED TO RESULT IN GALE FORCE
SOUTHWEST WINDS OVER MUCH OF LAKE SUPERIOR LATE TONIGHT INTO MONDAY
WITH GALE WINDS SHIFTING WEST ON MONDAY AFTERNOON OVER ERN LAKE
SUPERIOR BEFORE DIMINISHING BLO GALES MON EVENING. WINDS WILL
DIMINISH BY TUESDAY WITH A WEAKENING PRESSURE GRADIENT...BUT WILL
INCREASE OUT OF THE N-NW WEDNESDAY NIGHT INTO FRIDAY AS MUCH COLDER
SPREADS ACROSS THE REGION AND THE PRES GRADIENT TIGHTENS IN THE WAKE
OF A DEEPENING LOW PRESSURE SYSTEM. N/NW WINDS SHOULD REACH GALE OR
NEAR GALE FORCE LATE WED NIGHT INTO FRI MORNING WITH MODERATE HEAVY
FREEZING SPRAY THU NIGHT INTO FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 5 AM TO 4 PM EST MONDAY FOR LSZ267.
GALE WARNING FROM 3 AM TO 7 PM EST MONDAY FOR LSZ266.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 11 AM EST /10 AM
CST/ MONDAY FOR LSZ162.
GALE WARNING FROM 1 AM TO 3 PM EST MONDAY FOR LSZ263-264.
GALE WARNING FROM 7 AM TO 7 PM EST MONDAY FOR LSZ265.
GALE WATCH FROM MONDAY MORNING THROUGH MONDAY AFTERNOON FOR
LSZ243-244.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1220 AM EST SUN JAN 8 2012
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL NRN STREAM
FLOW THROUGH THE UPPER GREAT LAKES. A WEAK SHORTWAVE THAT HAS HELPED
BOOST LES INTENSITY TODAY WAS EXITING TO THE EAST OF LAKE SUPERIOR.
OTHERWISE...NO SIGNIFICANT SHRTWVS WERE NOTED UPSTREAM THAT WOULD
IMPACT WEATHER THROUGH SUN. AT THE SFC...A TROUGH FRONT WAS NEARLY
STATIONARY ACROSS NRN UPPER MI. 850 MB TEMPS NEAR -14C PROVIDED JUST
ENOUGH INSTABILITY FOR LIGHT LES WITH LOW LEVEL NW FLOW.
&&
.SHORT TERM...TONIGHT AND SUNDAY
WEAKER AND INCREASINGLY ANTICYCLONIC FLOW WITH SFC RDG MOVING IN
FROM THE WEST WILL TEND TO BACK WINDS MORE WRLY LATE TONIGHT INTO
SUNDAY. THE MOST FAVORABLE LOW LEVEL CONV WOULD FOCUS LES OVER THE
KEWEENAW PENINSULA AND FROM MUNISING EASTWARD ALONG THE ERN
SHORELINE. MAINTAINED HIGH CHC TO LIKELY POPS FOR ADDITIONAL LES
ACCUMS OF AN INCH OR LESS OVER THE KEWEENAW PENINSULA AND ERN
ALGER...LUCE AND NRN SCHOOLCRAFT COUNTIES. EXPECT DRY CONDITIONS TO
THE SOUTH.
A BAND OF 275K-280K ISENTROPIC ASCENT AND 900-800 MB FGEN MOVING
INTO THE WEST LATE AND ACROSS THE CWA LATE TONIGHT AND SUN MORNING
COULD PRODUCE SOME LIGHT SNOW WITH MINIMAL ACCUMULATIONS OF A FEW
TENTHS. SO...ONLY SLIGHT CHANCE POPS WERE INCLUDED AWAY FROM LAKE
SUPERIOR. LOW LEVEL BACKING MORE WRLY BY SUNDAY ALONG WITH MARGINAL
LAKE INSTABILITY (850 MB TEMPS CLIMBING TO AROUND -12C) SUPPORT ONLY
LOW CHC POPS FOR LES OVER MAINLY THE KEWEENAW PENINSULA AND
SHORELINE AREAS EAST OF MUNISING. WITH THE LIGHT WIND FIELD
UNCERTAINTY REMAINS WHETHER ANY MESO LOW OR SHORELINE PARALLEL BAND
WILL DEVELOP...PER HIGH RES WRF/ARW.
.LONG TERM /00Z MON THROUGH NEXT SAT/...
STARTING MONDAY AT 00Z THERE WILL BE A BROAD 500MB TROUGH OVER ERN
CANADA/NERN CONUS...WITH A SHARP TROUGH BRANCHING OFF OF THAT FROM
OVER OUR CWA TO THE AZ/NM BORDER...AND A 500MB RIDGE W OF THAT
TROUGH. BY TUESDAY...THE AZ/NM TROUGH WILL CLOSE OFF AND MOVE TO
TX...BREAKING FREE OF THE ERN CANADA TROUGH AS IT MOVES E. ANOTHER
SYSTEM WILL PUSH INTO THE PACIFIC NW...WHICH WILL PUSH THE W COAST
RIDGE OVER THE CWA DURING THE DAY TUESDAY. MODELS HAVE HAD POOR RUN
TO RUN CONTINUITY WITH THE NEXT SYSTEM MOVING IN FOR THE MIDDLE OF
THE WEEK. MODELS BRING AN UPPER TROUGH OFF A CLOSED LOW OVER AK INTO
THE REGION...DEEPENING IT INTO A CLOSED LOW NEAR OR OVER THE CWA
WED. THE CLOSED LOW MOVES OFF TO THE NE THU NIGHT OR FRIDAY...WITH
AN UPPER TROUGH HANGING AROUND E OF THE CWA THROUGH SATURDAY.
FOR MON...A SHORTWAVE WILL MOVE THROUGH THE REGION...BUT THE BEST
DYNAMICS WILL BE FARTHER NE...SO ANY POPS WERE LIMITED TO LAKE
SUPERIO OR ERN UPPER MI. EVEN WITH CLOUD COVER FROM THIS
SYSTEM...HIGH WILL BE IN THE MID TO UPPER 30S WITH WAA FROM THE W
THROUGH THE DAY. 850MB TEMPS AT 00Z MON WILL BE AROUND
-9C...INCREASING TO AROUND 0C BY 00Z TUE.
MON NIGHT AND TUE...AS THE UPPER RIDGE MOVES OVERHEAD TUE...EXPECT
DRY CONDITIONS WITH FEWER CLOUDS...ESPECIALLY BEFORE EVENING.
THICKNESSES WILL BE SLIGHTLY INCREASED TUE...SO HIGHS WILL BE A
COUPLE DEGREES WARMER AROUND 40.
WED THROUGH FRI...AS NOTED PREVIOUSLY...MODELS SHOW INCREASED
DISAGREEMENT AND DECREASED RUN TO RUN CONTINUITY WITH A SYSTEM
EJECTING OUT OF AK. COMPARING THE 12Z/07 GFS...00Z/07 ECMWF...AND
12Z/07 GEM SOLUTIONS...THE GEM WAS RULED OUT SINCE IT SHOWS A FAR
DIFFERENT SCENARIO THAN THE OTHER TWO MODELS. BOTH THE GFS AND ECMWF
BRING A 500MB TROUGH FROM A CLOSED LOW OVER AK...SHOWING A LOW
CLOSING OFF FROM THE TIP OF THE TROUGH AS IT MOVES SE. MODELS THEN
DEPICT THE TROUGH MOVING TOWARD THE CWA BEFORE DEEPENING JUST
UPSTREAM OF THE CWA IN RESPONSE TO JET INTERACTION. THE GFS CLOSES
THE UPPER LOW OFF AS IT MOVES ACROSS THE CENTRAL MANITOBA/ONTARIO
BORDER AROUND 18Z WED...AND MARCHES IT JUST N OF LAKE SUPERIOR
BEFORE MOVING INTO QUEBEC AROUND 06Z FRI. THE STRONGER ECMWF CLOSES
THE LOW OFF OVER THE ND/MANITOBA BORDER AROUND 12Z WED...THEN
CONTINUES TO DEEPEN THE SYSTEM AS IT MOVES TO THE IL/WI BORDER BY
12Z THU...THEN TO THE LOWER GREAT LAKES BY 12Z FRI. SET THE CLOCK
BACK A BIT TO FIND WHERE MODELS START TO DIVERGE WITH THIS SYSTEM.
BACK WHEN THE TROUGH IS MOVING OVER WRN CANADA...THE SLIGHTLY
STRONGER ECMWF IS MUCH FASTER TO CLOSE OFF THAT LOW...WHICH THEN
MOVES S AND STAYS WELL OFF THE CA COAST THROUGH THE EVENT. THE
GFS...ON THE OTHER HAND...CLOSES THE LOW OFF OVER SRN CA...WHICH
LEADS TO THAT LOW MOVING INTO AZ AND NM THROUGH THE EVENT. HAVING
THAT LOW IN PLACE THE GFS PUTS IT CUTS OFF SOME ACCESS TO COMPONENTS
OF BOTH THE NRN AND SRN STREAM JETS...WHICH IS WHY THE SYSTEM DOES
NOT STRENGTHEN AS MUCH AND STAYS FARTHER N WITH THE GFS SOLUTION.
REGARDLESS OF SOLUTION...BOTH MODELS BRING 850MB TEMPS AS LOW AS
-20C OVER LAKE SUPERIOR WITH THE SYSTEM. THE GFS HAS NW BL
WINDS...WHILE THE ECMWF HAS MORE NORTHERLY WINDS SINCE THE SFC LOW
WILL BE MORE TO OUR E. AT THIS POINT...I FEEL COMFORTABLE WITH
LIKELY POPS SINCE CONFIDENCE THAT IT WILL SNOW IS MUCH HIGHER THAN
THE CONFIDENCE OF WHERE THE MOST SNOW WILL FALL. IF THE ECMWF IS
CORRECT...WE COULD BE LOOKING AT VERY SIGNIFICANT SNOWFALL
AMOUNTS...ESPECIALLY IN NORTH WIND SNOWBELTS. THE GFS SOLUTION WOULD
LEAD TO MUCH LOWER SNOWFALL TOTALS THAN THE ECMWF...SINCE THE ECMWF
ALSO CONTRIBUTES A SIGNIFICANT AMOUNT OF SYNOPTIC PRECIP.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
EXPECT PERIODIC LIGHT LK EFFECT SNOW SHOWERS AT KCMX THROUGH TONIGHT
INTO EARLY SUNDAY MORNING. CIGS SHOULD DROP TO MVFR AT ALL SITES
LATE TONIGHT AS A WEAK SYSTEM MOVES THROUGH AND BRINGS IN SOME LOW
LEVEL MOISTURE. EXPECT IMPROVING CONDITIONS AT ALL SITES BY
AFTERNOON WITH DRIER AIR COMING IN AS CONDITIONS WILL GO TO VFR AND
STAY THERE THROUGH THE REST OF THE TAF PERIOD.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
LOW PRESSURE IS FORECAST TO SLIDE ACROSS ONTARIO THROUGH MONDAY.
STRONG PRESSURE FALLS NORTH OF LAKE SUPERIOR AND AN INCREASING
PRESSURE GRADIENT IS EXPECTED TO RESULT IN GALE FORCE SOUTHWESTERLY
WINDS OVER MUCH OF LAKE SUPERIOR ON MONDAY. A GALE WATCH REMAIN IN
EFFECT FOR THIS TIME FRAME. WINDS SETTLE DOWN BY TUESDAY WITH
WEAKENING PRESSURE GRADIENT...BUT INCREASE WEDNESDAY INTO THURSDAY
AS LOW PRESSURE SYSTEM/STRONG COLD FRONT PUSH ACROSS THE UPPER GREAT
LAKES REGION. EXACT WIND DIRECTION/SPEEDS ARE UNCERTAIN FOR
WEDNESDAY...BUT EVENTUALLY N/NW WINDS SHOULD REACH GALE OR NEAR GALE
FORCE BY THURSDAY IN WAKE OF THE LOW PRESSURE/COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON FOR
LSZ162-263>266.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
844 PM MST MON JAN 9 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...
UPDATED THE FORECAST TONIGHT TO BEGIN THE FINE TUNING OF THE ONSET
OF THE TUESDAY SYSTEM. CLOSE ENOUGH NOW TO INTEGRATE MORE OF THE
HRRR MODEL INTO THE VERY SHORT TERM GRIDS. I SPLIT THEM UP INTO 3
HOURLY GRIDS TO SHOW MORE DETAIL AS THE SPRINKLES BEGIN TO FALL
OVER OUR WESTERN ZONES. LOOKS LIKE OVERNIGHT TEMPERATURES THERE
FOR THE MOST PART WILL REMAIN ABOVE FREEZING AS MOST OF THOSE
LOCATIONS RECORDED NEW RECORD HIGH TEMPERATURES EARLIER TODAY.
ACKNOWLEDGE THE GFS AND NAM OPERATIONAL MODEL DATA...BUT FAVORED
MORE OF THE HRRR MODEL DEPICTION. JUST NOW...REGIONAL RADAR
REFLECTIVITY IS BEGINNING TO SHOW RETURNS OVER WESTERN FERGUS
COUNTY. EXPECT THAT TO INCREASE AND SPREAD EASTWARD AND
NORTHEASTWARD OVER THE NEXT 6 HOURS OR SO. BMICKELSON
PREVIOUS SHORT TERM DISCUSSION...HIGH PRESSURE OVER SOUTHERN
CALIFORNIA STILL ANCHORS AN UPPER LEVEL RIDGE OVER THE NORTHWEST.
HOWEVER THE NEXT COLD FRONT DROPPING OUT OF THE GULF BEGINS TO
KNOCK DOWN THE RIDGE TONIGHT. THE ARCTIC FRONT WILL BE AT OUR
NORTHERN DOORSTEP BY 12Z TUESDAY. THE ASSOCIATED UPPER TROUGH
CONTAINS A COLD MASS OF AIR AT 700MB WITH MODELS SUGGESTING
TEMPERATURES OF AROUND -24*C TO -28*C. THIS WILL GIVE AN EXTRA
PUNCH TO THE FRONT. AN EXTENSION OF THE TROUGH DEVELOPS IN THE
EASTERN PACIFIC THAT WILL SEND A SHOT OF MOISTURE INTO THE
NORTHERN ROCKIES TONIGHT. THIS MOISTURE ARRIVES OVER THE PRAIRIE
AS THE COLD FRONT SHOWS UP ALONG THE INTERNATIONAL BORDER TUESDAY
MORNING. 850MB TEMPERATURES THAT WERE AROUND 6-8*C AT 00Z WILL
DROP TO AROUND -6*C AT 18Z IN THE NW ZONES...AND TO -8*C TO -12*C
BY 00Z WEDNESDAY. SO THERE WILL BE A TRANSITION FROM RAIN TO SNOW
IN SOME AREAS. WITH OVERNIGHT LOWS IN THE MID 20S...NORTHERN AREAS
COULD BEGIN WITH SNOW TUESDAY MORNING. A BLEND OF GFS... NAM...GEM
AND THE EC SUGGEST THAT QPF BEFORE 18Z WILL BE CONFINED MOSTLY TO
THE WESTERN ZONES WITH AROUND 0.05 TO 0.10 INCH OF WATER. THE QPF
SPREADS ACROSS THE REMAINDER OF THE ZONES DURING THE
AFTERNOON...WITH ABOUT THE SAME AMOUNT OF QPF. USED THE WESTERN
REGION WEATHER TOOL TO FIX PRECIPITATION TYPE AND THE CAR SNOW
AMOUNT TOOL TO ESTABLISH SNOW RATIO. THE BEST AREAS FOR
ACCUMULATING SNOW WILL BE ALONG THE NORTHERN TIER...WITH A NON-
ACCUMULATING MIX ELSEWHERE. BY EVENING ANY REMAINING PRECIPITATION
WILL BE ALL SNOW BUT WITH MINIMAL QPF. EXPECT SMALL AMOUNTS OF QPF
OVERNIGHT WITH SNOW MOSTLY ENDING. A STRONG PRESSURE GRADIENT
DEVELOPS ACROSS THE AREA BY AFTERNOON WHICH WILL GENERATE
NORTHWEST WINDS OF AROUND 20KTS. THIS WILL BE RE-ENFORCED BY CAA
OF 30 TO 40 KTS AT 850MB. MIXING SHOULD IMPROVE AFTER 00Z THURSDAY
WITH PARTIALLY CLEARING SKIES. THE RESULT COULD BE COLD WINDS
TUESDAY NIGHT. WITH GUSTS GREATER THAN 25KTS...ADDED PATCHY
BLOWING SNOW THROUGH WEDNESDAY MORNING TO NORTHERN...THEN EASTERN
ZONES. 850MB TEMPERATURES RANGE FROM AROUND -16*C TO -20*C BY 12Z.
SO OVERNIGHT LOWS COULD FALL INTO THE SINGLE DIGITS IN SOME
LOCATIONS. WIND CHILLS IN THE RANGE OF AROUND -15*F TO -20*F ARE
POSSIBLE ALONG THE NORTHERN TIER AND OVER ANY HIGH ELEVATIONS.
WEDNESDAY...LOW STRATUS CENTERED OVER SOUTHERN SASKATCHEWAN AND
MANITOBA WILL SPREAD OVER MUCH OF EASTERN NEMONT WEDNESDAY
MORNING BEFORE BEING PUSHED OUT OF THE AREA IN THE AFTERNOON BY A
RE-DEVELOPING RIDGE AND SURFACE HIGH...ALONG WITH AN APPROACHING
WARM FRONT. HOWEVER MAXIMUM TEMPERATURES SHOULD ONLY BE ABLE TO
RISE INTO THE TEENS AND 20S WHILE WINDS DIMINISH BY SUNSET. SCT
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
UPDATE...WEDNESDAY NIGHT THERE IS GOOD AGREEMENT IN THE MODELS
FOR ARCTIC AIR TO LINGER OVER NORTHEAST MONTANA...AND WHEN PARTIAL
CLEARING OF SKIES IS CONSIDERED...TEMPERATURES SHOULD HAVE NO
PROBLEMS FALLING OFF TO NEAR ZERO. THUS TRENDED DOWN TEMPERATURES.
THURSDAY THROUGH SATURDAY NORTHWEST FLOW WITH EMBEDDED SHORTWAVE
FEATURES WILL PASS THROUGH...WITH WARMING ON THURSDAY AND SATURDAY
AND A COLD FRONTAL PASSAGE ON FRIDAY. THERE IS SOME POTENTIAL FOR
LIGHT PRECIP WITH THE FRONT ON FRIDAY...BUT THERE WAS ENOUGH MODEL
DISAGREEMENT THAT THE GHOST 10 POPS SEEMED REASONABLE.
FOR SUNDAY INTO MONDAY THE MODELS CONTINUE TO STRUGGLE WITH THE GEM
AND ECMWF SUPPORTING A SUBSTANTIAL PUSH OF ARCTIC AIR INTO NORTHEAST
MONTANA. THE GFS AND DGEX REMAIN IN A WARMER PATTERN SIMILAR TO
THE RECENT PATTERN. GIVEN THE CONSISTENCY OF THE ECMWF AND ITS SUPPORT
WITH THE GEM DECIDED TO FAVOR A COLDER PATTERN AND TRENDED TEMPS
DOWNWARD. CONTINUED THE MAINLY DRY PATTERN AS MOISTURE LOOKS
SOMEWHAT LACKING WITH THE SYSTEM. GILCHRIST
PREVIOUS DISCUSSION...FROM WED NIGHT INTO THE WEEKEND...NORTHWEST
FLOW ALOFT IS EXPECTED WITH SHORTWAVE RIDGES AND TROUGHS
DIFFERENTLY. GFS IS SOMEWHAT FASTER THAN THE ECMWF WITH THE RIDGE
BUILDING INTO THE AREA ON THURSDAY. THIS WILL BRING SOMEWHAT
WARMER TEMPERATURES BACK INTO THE AREA. SHORTWAVE TROUGH AND COLD
FRONT WILL FOLLOW ON FRIDAY. ECMWF KEEPS THE MAIN DYNAMICS AND
MOISTURE IN SASKATCHEWAN AT THIS POINT WHILE THE GFS RUNS IT
THROUGH MONTANA. WILL SIDE ON THE DRIER ECMWF AT THE MOMENT AND
KEEP FORECAST DRY.
NORTHWEST FLOW ALOFT CONTINUES ON SATURDAY WITH ANOTHER SHORTWAVE
RIDGE SATURDAY NIGHT. AT THIS POINT THE GFS IS STRONGER WITH THE
RIDGE THAN THE ECMWF. EITHER WAY...IT LOOKS LIKE A WARMER THAN
NORMAL TEMPERATURES WITH DRY WEATHER.
SIGNIFICANT MODEL DIFFERENCES DEVELOP ON SUNDAY. GFS EXPANDS THE
RIDGE OVER THE WESTERN U.S. AND MAINTAINS THE WARMTH OF LATE INTO
NEXT WEEK. MEANWHILE...THE GEM AND ECMWF DIG A DEEP UPPER TROUGH
OVER WESTERN CANADA AND BRING A STRONG COLD FRONT ON SUNDAY WITH
MUCH COLDER ARCTIC AIR MASS. THE DIFFERENCES IN THE MODELS COMBINED
WITH RUN TO RUN DIFFERENCES LEAD TOWARDS A VERY LOW CONFIDENCE
FORECAST AT THIS POINT. THERE ARE ALSO CONSIDERABLE DIFFERENCES IN
THE GFS ENSEMBLES CONCERNING THE FLOW ALOFT. WILL TREND
TEMPERATURES SOMEWHAT COLDER FOR NOW. FORRESTER
&&
.AVIATION...
VFR. MID AND HIGH LEVEL CLOUDS WILL INCREASE TONIGHT WITH WEST
WINDS AROUND 10 KNOTS CONTINUING. CLOUDS WILL FURTHER LOWER
TUESDAY MORNING THANKS TO AN APPROACHING COLD FRONT...WHICH WILL
ALSO DRIVE WIDESPREAD RAIN CHANGING TO SNOW SHOWERS. STRONG GUSTY
NORTHWEST WINDS WILL ALSO ACCOMPANY THE FRONT TUESDAY
MORNING...MAKING FOR LESS THAN IDEAL FLYING WEATHER.
GILCHRIST/PROTON
&&
.CLIMATE...
MANY NEW RECORD HIGH TEMPERATURES ACROSS THE AREA TODAY.
LOCATION NEW HIGH TEMPERATURE OLD RECORD
GLASGOW 56 54 IN 1933
ST MARIE 54 51 IN 2002
SCOBEY 4 NW 53 50 IN 2002
WOLF POINT 53 47 IN 2002
JORDAN 59 50 IN 2001
BREDETTE 50 47 IN 1953
MALTA 59 53 IN 2002
NASHUA 57 53 IN 2002
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
647 PM EST MON JAN 9 2012
.SYNOPSIS...
A SLOW-MOVING FRONT WILL MOVE SOUTH ACROSS SOUTH CAROLINA TONIGHT
THROUGH TUESDAY. A STRONGER LOW PRESSURE SYSTEM WILL MOVE ACROSS OUR
REGION ON WEDNESDAY. THIS WILL BRING A BETTER CHANCE OF RAIN. HIGH
PRESSURE WILL FOLLOW FOR THE REMAINDER OF THE PERIOD WITH MORE
SEASONAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 PM MONDAY...THE SURFACE FRONT HAS PUSHED AS FAR NORTH AS
SOUTHERN FLORENCE AND HORRY COUNTIES EARLIER THIS AFTERNOON...BUT IS
NOW RETURNING SOUTHWARD...PUSHED FROM THE NORTH BY A WEAK BUBBLE OF
HIGH PRESSURE. WINDS HAVE SHIFTED TO THE NORTH IN GEORGETOWN SC
WITHIN THE PAST HOUR...A SIGN THE FRONT HAS MOVED THROUGH THAT
LOCATION. COOL HUMID AIR WILL OVERSPREAD ALL OF OUR FORECAST AREA
OVERNIGHT.
THE BIGGEST FORECAST CONCERN IS FOG...PARTICULARLY THE POTENTIAL FOR
DENSE FOG ACROSS INLAND PORTIONS OF THE EASTERN CAROLINAS. RAIN
EARLIER TODAY MAINLY ACROSS NORTH CAROLINA ADDED PLENTY OF LOW-LEVEL
MOISTURE. RELATIVE HUMIDITIES ARE IN THE 95-100 PERCENT RANGE ALONG
AND NORTH OF A LINE FROM FLORENCE TO MARION TO WHITEVILLE AND
BURGAW...AND VISIBILITIES HAVE ALREADY DROPPED TO 1/2 MILE OR LESS
AT TIMES IN THE DARLINGTON/HARTSVILLE/BENNETTSVILLE VICINITY. NOT
ENOUGH 1/4 MILE VISIBILITIES HAVE SHOWN UP ON ASOS/AWOS OBS YET TO
SAY WE`RE DEALING WITH A WIDESPREAD DENSE FOG EVENT...SO WE ARE NOT
READY TO ISSUE AN ADVISORY JUST YET.
REVIEWING LITERALLY ALL THE SHORT-RANGE MODELS AVAILABLE TO US
REVEALS A WIDE VARIETY OF IDEAS ABOUT WHAT WINDS IN THE 0-1000 FT
LAYER WILL DO OVER THE NEXT FEW HOURS. LIGHT WINDS THROUGH THIS
LAYER (AS FORECAST BY THE 22Z RUC AND 18Z NAM) WOULD ALLOW FOG TO
CONTINUE AND TO BECOME DENSE OVERNIGHT) WHILE STRONGER BOUNDARY LAYER
WINDS (FORECAST BY THE 18Z GFS, THE 12Z ARW-NAM, AND THE 21Z HRRR)
WOULD TEND TO KEEP SURFACE VISIBILITIES IN THE 1-3 MILE RANGE WITH A
VERY LOW STRATUS CEILING INSTEAD. THERE IS NO CLEAR REASON TO CHOOSE
EITHER SOLUTION OVER THE OTHER AT THIS POINT...SO WE WILL CLOSELY
MONITOR OBSERVATIONS...RADAR WIND PROFILES AND THE 00Z SOUNDINGS FOR
ANY CLUE WHICH WAY TO GO WITH THE FOG THREAT TONIGHT.
SCATTERED SHOWERS MOVING OFF THE COAST PROBABLY END THE THREAT FOR
MEASURABLE RAIN TONIGHT SOUTH OF CAPE FEAR. ADDITIONAL SHOWER
ACTIVITY ACROSS NORTH CAROLINA MAY IMPACT SOUTHEASTERN NORTH
CAROLINA LATER THIS EVENING. POPS ARE GENERALLY IN THE 30-50 PERCENT
RANGE HERE...BUT MAY NEED TO BE RAISED ACROSS NORTHERN SECTIONS OF
ROBESON...BLADEN AND PENDER COUNTIES DEPENDING ON RADAR TRENDS
THROUGH THE EVENING.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...UPPER CONFLUENCE OVER THE MID ATLANTIC STATES
WILL KEEP A BUBBLE OF HIGH PRESSURE IN PLACE UNDERNEATH. THIS IN
TURN KEEPS FRONTAL BOUNDARY STALLED JUST TO OUR SOUTH. MEANWHILE A
CUTOFF UPPER LOW WILL CROSS TEXAS WITH A DEEPENING SURFACE LOW
PROGRESSING EASTWARD JUST AHEAD OF THE UPPER LOW. WITH THE EASTWARD
TRANSLATION OF THESE SYSTEMS LOW LEVEL FLOW WILL BACK AND INCREASE
TUESDAY NIGHT EVENTUALLY LEADING TO FAIRLY AGGRESSIVE MOISTURE
ADVECTION. THIS WILL AT FIRST GO TOWARDS CLOUD GENERATION BUT RAIN
CHANCES WILL ALSO INCREASE OVER THE LATTER HALF OF THE NIGHT. WARM
FRONT EVENTUALLY LIFTS NORTH THROUGH THE AREA ON WEDNESDAY ALTHOUGH
THERE ARE SOME DIFFERENCES BTW THE GFS AND WRF...WITH THE FORMER
BEING A LITTLE FASTER. A BLEND OF SOLNS SEEMS THE BEST COURSE RIGHT
NOW WHICH WILL STILL OPEN UP THE POSSIBILITY OF SOME WEAK
INSTABILITY DEVELOPING. THE MAIN SIGNIFICANCE OF THIS IS THAT LOW
LEVEL WIND FIELDS WILL BE STRONG ENOUGH FOR A SMALL TORNADO THREAT
GIVEN SUFFICIENT VIRTUAL VELOCITY IN CONVECTIVE ELEMENTS WHILE THE
AREA SITS IN THE WARM SECTOR.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...EXITING SYSTEM AT THE START OF THE PERIOD WILL
LEAVE A MAINLY TEMP FORECAST. 12Z GFS DOES DEVELOP ANOTHER SOUTHERN
STREAM SYSTEM OVER THE WESTERN GULF OF MEXICO...IMPACTING THE REGION
EARLY NEXT WEEK. IT IS REALLY THE ONLY MEDIUM RANGE GUIDANCE TO
DEVELOP THE SYSTEM SO DEEPLY...THE ECMWF/CANADIAN KEEP THIS FEATURE
AS A WEAK WAVE ALONG A STALLED BOUNDARY. THIS HAS TO DO WITH THE WAY
THE VARIOUS MODELS HANDLE A 5H CUTOFF LOW MOVING INTO THE
SOUTHWESTERN CONUS OVER THE WEEKEND. THE GFS IS QUICK TO MOVE THE
LOW WHICH IT HAS CLOSER TO THE WESTERN US COAST. THE GFS SOLUTION
DOES NOT HAVE A LOT OF SUPPORT FROM ITS ENSEMBLE MEMBERS AND HAS
BEEN IGNORED IN FAVOR OF THE SLOWER ECMWF/HPC SOLUTIONS.
TEMPERATURES START OUT ABOVE CLIMO BUT PASSAGE OF ARCTIC FRONT FRI
MORNING AND DEEP 5H TROUGH MOVING IN WILL KNOCK TEMPERATURES WELL
BELOW CLIMO FRI NIGHT INTO SAT. FRI WILL BE A TRANSITION DAY WITH
TEMPS SLOWLY RISING INTO THE MID 50 IN THE FACE OF COLD ADVECTION.
ANY COLD ADVECTION ENDS BY SAT AFTERNOON BUT A REINFORCING SHOT OF
COLD AIR EARLY SUN MAY DROP TEMPS WELL BELOW CLIMO. WEAK WARM
ADVECTION WILL START LATE MON...BUT IT WILL HAVE LITTLE SUCCESS IN
WARMING TEMPS ABOVE CLIMO BEFORE THE END OF THE PERIOD.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...IFR/MVFR CONDITIONS EXPECTED THROUGH THE OVERNIGHT
HOURS...IMPROVING TO VFR BY THE END OF THE VALID PERIOD.
CURRENT RADAR DEPICTS THAT MOST OF THE RAIN HAS MOVED OUT OF THE
AREA...THOUGH CANNOT RULE OUT A FEW SPRINKLES TO STILL LINGER ALONG
THE COAST. LOWERED VISIBILITY DUE TO FOG AND LOWERED CIGS AROUND
400-500FT HAVE INFILTRATED INTO THE INLAND TERMINALS FROM BOTH THE
WEST AND THE NORTH. SOME LOCATIONS WEST OF KFLO HAVE ALREADY HAD
VISIBILITIES DECREE TO AROUND 1/4SM. CURRENT MODELS ARE IN LITTLE TO
NO AGREEMENT...WHERE SOME ARE SUGGESTING AN INCREASE IN BOUNDARY
LAYER WINDS LATER OVERNIGHT...INSINUATING RESTRICTIONS WOULD
LIFT...AND WHERE OTHER MODELS KEEP WINDS NEARLY CALM. GIVEN LOWERED
CONFIDENCE ON DURATION AND RESTRICTIONS...HAVE GENERALLY KEPT
RESTRICTIONS DUE TO LOW CIGS AND FOG THROUGH TUESDAY MORNING...AND
THEN HAVE INTRODUCED A TREND OF IMPROVING CONDITIONS THROUGH THE
VALID PERIOD. WOULD OVERALL ANTICIPATE IFR MAINLY...AND POTENTIALLY
LIFR...AT INLAND TERMINALS...AND MVFR AT COASTALS.
WINDS WILL BE GENERALLY NORTH THROUGH TUESDAY MIDDAY...WITH WINDS
AOB 5 KTS...BECOMING EAST TOWARDS THE END OF THE PERIOD.
EXTENDED OUTLOOK...HIGH CONFIDENCE OF ISOLATED THUNDERSTORMS AND
TEMPO IFR WEDNESDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 PM MONDAY...AFTER SNEAKING NORTH ALONG THE SOUTH CAROLINA
COAST EARLIER TODAY...THE NEARLY STATIONARY FRONT IS MOVING SOUTH
AGAIN. WINDS HAVE SHIFTED TO THE NORTH WITHIN THE PAST HOUR AT
THE GEORGETOWN AIRPORT SIGNIFYING THE FRONT HAS PASSED SOUTH OF THIS
LOCATION. LIGHT NORTH WINDS ARE EXPECTED THROUGH EARLY TUESDAY
MORNING...SHIFTING MORE WESTERLY LATE TONIGHT. SCATTERED SHOWERS
WILL SLIDE OFF THE COAST EARLY THIS EVENING...AND A FEW ADDITIONAL
SHOWERS ARE POSSIBLE LATER TONIGHT MAINLY NORTH OF CAPE FEAR. SEAS
AROUND 2 FEET WILL CONTINUE THROUGH THE NIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...TUESDAY WILL BRING A SMALL BUBBLE OF HIGH
PRESSURE PROGRESSING EAST ACROSS THE MID ATLANTIC STATES. AS SUCH
WINDS LOCALLY WILL BE QUITE LIGHT AND SHOW DIRECTIONAL VEERING AS
THE DAY PROGRESSES...ESPECIALLY LATE IN THE DAY AND INTO TUESDAY
NIGHT. WEDNESDAY WILL BRING SOME PRETTY QUICK CHANGES AND
DETERIORATION OF CONDITIONS AS A WARM FRONT LIFTS NORTH OF THE AREA
AND THE WATERS FIND THEMSELVES IN A GUSTY WARM SECTOR. WIND AND SEAS
SHOULD RAMP UP TO WHERE A SMALL CRAFT ADVISORY BECOMES
NEEDED...ALTHOUGH COOLER SSTS COULD INHIBIT THE FORMER.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 3 PM MONDAY...15 TO 20 KT SOUTHWEST FLOW WILL LIKELY HAVE SEAS
RIGHT AROUND 6 FT WELL AWAY FROM SHORE AT THE START OF THE PERIOD.
GRADIENT WILL SLOWLY RELAX WITH SEAS DROPPING BELOW 6 FT LATE THU OR
THU NIGHT. OFFSHORE FLOW IN THE WAKE OF ARCTIC FRONT FRI...BUT
STRONG COLD ADVECTION DOES NOT ARRIVE UNTIL FRI NIGHT. LACK OF
SIGNIFICANT GRADIENT WILL KEEP SUSTAINED WINDS IN THE 15 TO 20 KT
RANGE THRESHOLDS...BUT STRONG COLD ADVECTION MAY RESULT IN GUSTY
WINDS FRI NIGHT AND EARLY SAT. OFFSHORE FLOW CONTINUES SAT AND SAT
NIGHT BUT LACK OF COLD ADVECTION WILL LIMIT GUSTS WHILE GRADIENT
KEEPS SPEEDS AROUND 15 KT. DEVELOPMENT OF OFFSHORE FLOW FRI WILL
KNOCK SEAS TO 3 TO 4 FT BY MIDDAY AND 2 TO 3 FT FOR SAT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...III
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
118 PM EST SUN JAN 8 2012
.SYNOPSIS...
A COLD FRONT WILL STALL JUST SOUTH OF THE AREA TODAY. WEAK WAVES OF
LOW PRESSURE WILL DEVELOP ALONG THE FRONT TONIGHT INTO MONDAY...
RESULTING IN COOL AND DAMP CONDITIONS. DRY HIGH PRESSURE WILL RETURN
ON TUESDAY...FOLLOWED BY A POTENT STORM SYSTEM EXPECTED TO TRACK
ACROSS THE CAROLINAS ON WEDNESDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 952 AM SUNDAY...
FOR THE REST OF TODAY: LATEST OBSERVED WEATHER TRENDS REMAIN IN LINE
WITH THE EARLIER FORECAST. THE MOST RECENT SURFACE ANALYSES SHOW THE
COLD FRONT MAKING SLOW BUT STEADY SOUTHWARD PROGRESS THROUGH THE FAR
SOUTHERN CWA... WHILE SPRAWLING HIGH PRESSURE CENTERED OVER IL (AND
STRETCHING FROM THE HEARTLAND ACROSS THE MIDATLANTIC) ATTEMPTS TO
BUILD INTO CENTRAL NC. WHILE THE PATCHY LIGHT RAIN FROM EARLY THIS
MORNING HAS DISSIPATED AND EXITED... A BROKEN DECK OF CLOUDS
CONTINUES TO PUSH SLOWLY EASTWARD INTO OUR AREA... HAVING OVERSPREAD
ALL BUT THE EASTERN CWA THUS FAR. PATCHY SPRINKLES FORCED BY MASS
CONVERGENCE NEAR THE LOW LEVEL FRONTAL ZONE WILL REMAIN A
POSSIBILITY OVER THE SOUTHWEST AND SOUTHERN CWA FOR THE NEXT SEVERAL
HOURS... SO HAVE SLIGHTLY SPED UP THE TIMING OF PRECIP ARRIVAL HERE
BY A COUPLE OF HOURS. THIS INITIAL PRECIP SHOULD REMAIN VERY LIGHT
GIVEN THE LACK OF ANY STRONG LIFT AND THE SHALLOW NATURE OF THE
INCOMING MOIST ISENTROPIC UPGLIDE. A BETTER CHANCE OF RAIN WILL
ARRIVE AFTER 4 PM THIS AFTERNOON AS THE UPGLIDE-SUPPORTED PRECIP NOW
OVER TN/AL/GA -- ENHANCED BY A WEAK SURFACE LOW ALONG THE FRONT --
SPREADS INTO CENTRAL NC. BOTH EXTRAPOLATION AND RECENT HRRR RUNS
SUPPORT THIS TIMING. AFTERNOON TEMP RISE WILL BE LESS THAN TYPICAL
GIVEN THE INCOMING CLOUDS AND LOW LEVEL COLD AIR ADVECTION...
HOWEVER THIS ADVECTION WILL BE QUITE WEAK AND WE STILL ANTICIPATE
POCKETS OF SUNSHINE THIS AFTERNOON. HAVE NUDGED HIGHS UP A BIT TO
55-62. -GIH
TONIGHT:
THE 00Z GFS/NAM/ECMWF ALL SHOW ISENTROPIC LIFT STRENGTHENING OVER
THE AREA TONIGHT FROM THE SOUTHWEST AS THE AFOREMENTIONED LOW-LEVEL
RIDGE PROGRESSES SLOWLY EASTWARD TO THE BAHAMAS...RESULTING IN A
MORE FAVORABLE LOW-LEVEL GULF RETURN FLOW OVER THE CAROLINAS THAT
WILL OVERRUN THE COOL/DRY AIRMASS DEPOSITED IN THE WAKE OF THE
BACKDOOR COLD FRONT THIS MORNING. ALL OF THE MODEL GUIDANCE SHOWS A
TRACE TO SEVERAL HUNDREDTHS OF AN INCH OF RAIN ACROSS THE AREA
OVERNIGHT...ALTHOUGH JUST HOW WIDESPREAD PRECIPITATION WILL BE
REMAINS IN QUESTION. WILL CONTINUE TO SHOW A 50% CHANCE OF RAIN OVER
THE ENTIRE AREA OVERNIGHT...WITH PRECIPITATION AMOUNTS GENERALLY A
FEW HUNDREDTHS OF AN INCH OR LESS (NAM/ECMWF). THE GFS REMAINS AN
OUTLIER...SHOWING 0.10-0.15". LOWS TONIGHT WILL HIGHLY DEPEND ON
WHERE AND HOW MUCH PRECIPITATION OCCURS. WHERE PRECIP DOES OCCUR...
GIVEN THE COOL/DRY SURFACE AIRMASS IN PLACE...A HYBRID CAD WEDGE
WILL DEVELOP...AND EVAP COOLING WOULD KEEPS TEMPS A FEW DEGREES
LOWER THAN AREAS WITHOUT PRECIP. GIVEN THE AFOREMENTIONED
UNCERTAINTY...AT THIS TIME WILL CONTINUE TO FOLLOW MOS GUIDANCE...
WITH LOWS RANGING FROM THE UPPER 30S IN THE NORTH TO LOWER 40S IN
THE SOUTH. -VINCENT
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 330 AM SUNDAY...
MONDAY:
THE WEAKENING SHEAR AXIS EXTENDING ENE FROM THE CENTRAL PLAINS INTO
NEW ENGLAND BY 12Z MONDAY IS PROGGED TO CONTINUE WEAKENING AS IT
PROGRESSES EAST OR ESE TOWARD THE MID-ATLANTIC ON MONDAY. THE
AFOREMENTIONED SHORTWAVE DIGGING SOUTHEAST INTO THE UPPER GREAT
LAKES BY 12Z MON IS PROGGED TO DIG INTO THE LOWER GREAT LAKES BY 00Z
TUESDAY...AND IS GENERALLY EXPECTED TO REMAIN TOO FAR NORTH TO HAVE
MUCH INFLUENCE ON CENTRAL NC DURING THE DAY MON. HOWEVER...THE SHEAR
AXIS (AND AN ASSOCIATED WEAK LOW-LEVEL TROUGH) PROGRESSING TOWARD
THE AREA SHOULD PROVIDE SUFFICIENT FORCING FOR PRECIPITATION VIA A
COMBINATION OF DPVA AND LOW/MID LEVEL ISENTROPIC LIFT. EXPECT PATCHY
DRIZZLE/LIGHT RAIN TO BE ONGOING MONDAY MORNING IN ASSOC/W
RELATIVELY WEAK ISENTROPIC LIFT...AND WILL CONTINUE TO SHOW A 50%
CHANCE OF RAIN EVERYWHERE THROUGH NOON. AFTER NOON...THE BETTER
FORCING MENTIONED ABOVE WILL ARRIVE...AND WILL INCREASE POPS TO
LIKELY (60%) GIVEN THAT MOST OF THE MODEL GUIDANCE (NAM/ECMWF) SHOWS
MEASURABLE PRECIP OVER CENTRAL NC MONDAY AFTERNOON (GFS AN OUTLIER
WITH BARELY MORE THAN A TRACE)...WITH ADDITIONAL SUPPORT FROM THE
NCEP HIGH-RES WRF-NMM WHICH SHOWS A WIDESPREAD SWATH OF RAIN
CROSSING CENTRAL NC FROM WEST-EAST BETWEEN ROUGHLY 18-00Z. HIGHS ON
MONDAY ARE DIFFICULT TO ASCERTAIN GIVEN SOME QUESTION WITH THE
LOCATION/EXTENT OF RAIN/DRIZZLE PRIOR EARLY IN THE DAY PRIOR TO THE
MORE WIDESPREAD RAIN EXPECTED IN THE AFTERNOON. REGARDLESS...EXPECT
A HYBRID OR IN-SITU CAD WEDGE TO DEVELOP...WITH HIGHS COOLER THAN IN
PREVIOUS DAYS. WILL INDICATE HIGHS RANGING FROM THE UPPER 40S N/NW
PIEDMONT TO LOWER 50S ELSEWHERE. IT IS POSSIBLE THAT HIGHS MAY NOT
EXCEED THE MID/UPPER 40S IF DRIZZLE OR LIGHT RAIN IS PREVALENT
THROUGH THE MORNING AND EARLY AFTERNOON HOURS PRIOR TO THE POTENTIAL
FOR MORE WIDESPREAD RAIN MOVING ACROSS THE AREA FROM WEST-EAST
MID/LATE AFTERNOON.
MONDAY NIGHT:
PRECIP ASSOC/W THE SHEAR AXIS AND RESULTING LOW/MID LEVEL ISENTROPIC
LIFT MON AFTERNOON SHOULD END BY 00-03Z TUE AS THE SHEAR AXIS
PROGRESSES OFFSHORE. THE AFOREMENTIONED H5 SHORTWAVE DIGGING INTO
THE LOWER GREAT LAKES DURING THE DAY MONDAY IS PROGGED TO AMPLIFY AS
IT DIGS INTO NEW ENGLAND AND THE MID-ATLANTIC BY 06Z TUE...FURTHER
AMPLIFYING AS IT PROGRESSES OFFSHORE THE MID-ATLANTIC BETWEEN
06-12Z. THIS AMPLIFYING UPPER LEVEL TROUGH WILL INITIATE
CYCLOGENESIS OFFSHORE THE CAROLINA COAST MON NIGHT AND RESULT IN A
FORMIDABLE EXTRATROPICAL CYCLONE IN THE NORTH ATLANTIC DURING THE
DAY TUE. OVER CENTRAL NC...HEIGHT/RISES SYNOPTIC SUBSIDENCE IN THE
WAKE OF THE SHEAR AXIS AND UPPER LEVEL TROUGH WILL RAPIDLY WARM/DRY
THE MID AND UPPER LEVELS AFTER 00-03Z TUE...IN ADDITION TO PRESSURE
RISES UPSTREAM IN THE OH VALLEY AND MID-ATLANTIC WHICH SHOULD HELP
FORCE A DRIER LOW-LEVEL AIRMASS INTO THE AREA BY 12Z TUE. IT IS
STILL NOT CLEAR WHETHER OR NOT THE CAD WEDGE WILL ENTIRELY SCOUR OUT
BY SUNRISE TUE. MODEL SOUNDINGS CONTINUE TO SHOW A VERY SHALLOW
SATURATED LAYER PERSISTING THROUGH 12Z TUE...AND HIGH PRESSURE
UPSTREAM OF THE AREA MAY NOT BE STRONG ENOUGH TO RESULT IN
APPRECIABLE SURFACE COLD ADVECTION TO COMPLETELY SCOUR OUT THE
WEDGE. WITH THE ABOVE IN MIND...UNCERTAINTY PERSISTS W/REGARD TO
CLOUD COVER AND LOW TEMPS. WILL SHOW AT LEAST A CLEARING TREND...
WITH LOWS RANGING FROM THE UPPER 30S TO LOWER 40S. -VINCENT
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 245 AM SUNDAY...
THE EJECTION OF THE MID-UPPER LOW FROM THE SOUTHWEST IS THE MAIN
WEATHER FEATURE TO WATCH THIS PERIOD... ALONG WITH A TURN TO COLDER
CONDITIONS LATE IN THE WEEK AND NEXT WEEKEND. OUT AHEAD OF THIS
STORM... IT WILL BECOME VERY MILD TO WARM AGAIN WITH TEMPERATURES
AVERAGING 10-15 DEGREES ABOVE THE 30 YEAR NORMALS.
THE MID-UPPER LOW IS ALREADY CUT OFF FROM THE MAIN WESTERLIES AND
THIS FAVORS THE MORE SOUTHERN AND SLOWER FORECASTS THAT THE NEW
EUROPEAN MODEL SUITE INDICATES. HOWEVER... NEARLY ALL MODEL GUIDANCE
INDICATES A FAIRLY SIMILAR SYSTEM WILL AFFECT OUR REGION CENTERED
AROUND WED-WED NIGHT... BUT THE TRACK IS OF CONCERN AS SOME MODELS
TRACK THE MID LEVEL CIRCULATION OVERHEAD... SOME TO OUR NW AND SOME
TO OUR SE. THE EXACT TRACK WILL DICTATE MANY ASPECTS OF THE SYSTEM
FOR OUR REGION... INCLUDING QPF/THUNDER CHANCES/TEMPS. FOR NOW... WE
WILL MAINTAIN OUR CURRENT FORECASTS... AND INCORPORATE A SLIGHTLY
SLOWER AND EVEN MORE MOIST SYSTEM PER THE LATEST EUROPEAN MODEL. IN
ADDITION... IF THE EUROPEAN TRACK VERIFIES... WE WOULD GE A
SIGNIFICANT RAIN WITH 1 TO 1.5 INCHES ACROSS THE REGION.
AFTER THE SYSTEM PASSES... IT WILL TURN COLDER... BUT REALLY NOT
UNTIL FRIDAY WHEN THE MAIN PUSH OF CAA IS EXPECTED. THERE IS STILL
QUITE A BIT OF DIFFERENCES IN THE MODEL FORECASTS AFTER FRIDAY WITH
THE CANADIAN INDICATING ANOTHER SOUTHERN BRANCH SYSTEM. MORE ON THIS
LATER.
SENSIBLE WEATHER HIGHLIGHTS... TUESDAY... SOME MORNING DRIZZLE...
BECOMING PARTLY CLOUDY AND WARMING INTO THE 60S. WEDNESDAY...
PERIODS OF RAIN WITH HIGHS 55-65. THURSDAY... RAIN ENDING. PARTLY
CLOUDY. HIGHS IN THE 60S. FRIDAY... TURNING COLDER AND BREEZY. HIGHS
IN THE 50S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 118 PM SUNDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WITH CEILINGS IN THE 4-7 KFT RANGE ARE EXPECTED TO
PREDOMINATE THROUGH ~00Z THIS EVENING...WITH CONDITIONS
DETERIORATING THEREAFTER. BY OR SHORTLY AFTER 00Z...LOW-LEVEL
(925-850 MB) FLOW WILL ASSUME MORE OF A SOUTHERLY COMPONENT. THIS IN
COMBINATION WITH OUR STALLED OUT BACKDOOR FRONT WILL RESULT IN
OVERRUNNING AND THE DEVELOPMENT OF MVFR CEILINGS AND AREAS OF LIGHT
RAIN...WITH A POTENTIAL FOR CONDITIONS TO FURTHER DETERIORATE TO IFR
AND POSSIBLY LIFR BY 12Z MON AND REMAINING THROUGH AROUND 18Z MON.
WHETHER OR NOT IFR/LIFR CONDITIONS DEVELOP PRIOR TO 12Z MON WILL
HEAVILY DEPEND ON WHETHER OR NOT MEASURABLE PRECIPITATION DEVELOPS
AND PERSISTS IN VICINITY OF THE TAF SITES. THE MOST LIKELY TIMEFRAME
FOR THE RAIN IS BETWEEN 02Z AND 09Z...BEGINNING AND ENDING FROM WEST
TO EAST.
LOOKING AHEAD:
CONDITIONS ARE EXPECTED TO FURTHER DETERIORATE TO IFR AND
POTENTIALLY LIFR OVER CENTRAL NC ON MONDAY AS PRECIPITATION FALLING
INTO THE INITIALLY COOL/DRY AIRMASS IN PLACE RESULTS IN THE
DEVELOPMENT OF A COLD AIR DAMMING WEDGE. SOME UNCERTAINTY PERSISTS
W/REGARD TO THE STRENGTH OF THE CAD WEDGE AND WHETHER OR NOT
CEILINGS WILL BECOME IFR/LIFR OR REMAIN MVFR OR BORDERLINE IFR. IF
WIDESPREAD LIGHT RAIN DEVELOPS TONIGHT AND PERSISTS INTO MONDAY...
THEN THE IFR/LIFR SCENARIO WOULD BE MORE LIKELY. CONVERSELY...IF
PRECIPITATION IS INTERMITTENT AND PATCHY...THEN MVFR OR BORDERLINE
IFR CEILINGS WOULD BE MORE LIKELY. CONDITIONS ARE EXPECTED TO
IMPROVE TO VFR EITHER LATE MONDAY NIGHT OR SHORTLY AFTER SUNRISE
TUESDAY AS DRY HIGH PRESSURE BUILDS BACK INTO THE AREA FROM THE
WEST/NW. HOWEVER...VFR CONDITIONS WILL BE SHORT-LIVED AS A POTENT
UPPER LEVEL LOW AND ASSOCIATED SFC LOW PRESSURE SYSTEM ARE PROGGED
TO TRACK OVER THE CAROLINAS/VA MID-WEEK. EXPECT CONDITIONS TO
DETERIORATE TUE NIGHT...WITH WIDESPREAD RAIN AND SUB-VFR CONDITIONS
DURING THE DAY WED...FOLLOWED BY A RETURN TO VFR CONDITIONS IN THE
WAKE OF A COLD FRONTAL PASSAGE WED EVE/NIGHT. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT/GIH
NEAR TERM...HARTFIELD/VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...KC/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
952 AM EST SUN JAN 8 2012
.SYNOPSIS...
A COLD FRONT WILL STALL JUST SOUTH OF THE AREA TODAY. WEAK WAVES OF
LOW PRESSURE WILL DEVELOP ALONG THE FRONT TONIGHT INTO MONDAY...
RESULTING IN COOL AND DAMP CONDITIONS. DRY HIGH PRESSURE WILL RETURN
ON TUESDAY...FOLLOWED BY A POTENT STORM SYSTEM EXPECTED TO TRACK
ACROSS THE CAROLINAS ON WEDNESDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 952 AM SUNDAY...
FOR THE REST OF TODAY: LATEST OBSERVED WEATHER TRENDS REMAIN IN LINE
WITH THE EARLIER FORECAST. THE MOST RECENT SURFACE ANALYSES SHOW THE
COLD FRONT MAKING SLOW BUT STEADY SOUTHWARD PROGRESS THROUGH THE FAR
SOUTHERN CWA... WHILE SPRAWLING HIGH PRESSURE CENTERED OVER IL (AND
STRETCHING FROM THE HEARTLAND ACROSS THE MIDATLANTIC) ATTEMPTS TO
BUILD INTO CENTRAL NC. WHILE THE PATCHY LIGHT RAIN FROM EARLY THIS
MORNING HAS DISSIPATED AND EXITED... A BROKEN DECK OF CLOUDS
CONTINUES TO PUSH SLOWLY EASTWARD INTO OUR AREA... HAVING OVERSPREAD
ALL BUT THE EASTERN CWA THUS FAR. PATCHY SPRINKLES FORCED BY MASS
CONVERGENCE NEAR THE LOW LEVEL FRONTAL ZONE WILL REMAIN A
POSSIBILITY OVER THE SOUTHWEST AND SOUTHERN CWA FOR THE NEXT SEVERAL
HOURS... SO HAVE SLIGHTLY SPED UP THE TIMING OF PRECIP ARRIVAL HERE
BY A COUPLE OF HOURS. THIS INITIAL PRECIP SHOULD REMAIN VERY LIGHT
GIVEN THE LACK OF ANY STRONG LIFT AND THE SHALLOW NATURE OF THE
INCOMING MOIST ISENTROPIC UPGLIDE. A BETTER CHANCE OF RAIN WILL
ARRIVE AFTER 4 PM THIS AFTERNOON AS THE UPGLIDE-SUPPORTED PRECIP NOW
OVER TN/AL/GA -- ENHANCED BY A WEAK SURFACE LOW ALONG THE FRONT --
SPREADS INTO CENTRAL NC. BOTH EXTRAPOLATION AND RECENT HRRR RUNS
SUPPORT THIS TIMING. AFTERNOON TEMP RISE WILL BE LESS THAN TYPICAL
GIVEN THE INCOMING CLOUDS AND LOW LEVEL COLD AIR ADVECTION...
HOWEVER THIS ADVECTION WILL BE QUITE WEAK AND WE STILL ANTICIPATE
POCKETS OF SUNSHINE THIS AFTERNOON. HAVE NUDGED HIGHS UP A BIT TO
55-62. -GIH
TONIGHT:
THE 00Z GFS/NAM/ECMWF ALL SHOW ISENTROPIC LIFT STRENGTHENING OVER
THE AREA TONIGHT FROM THE SOUTHWEST AS THE AFOREMENTIONED LOW-LEVEL
RIDGE PROGRESSES SLOWLY EASTWARD TO THE BAHAMAS...RESULTING IN A
MORE FAVORABLE LOW-LEVEL GULF RETURN FLOW OVER THE CAROLINAS THAT
WILL OVERRUN THE COOL/DRY AIRMASS DEPOSITED IN THE WAKE OF THE
BACKDOOR COLD FRONT THIS MORNING. ALL OF THE MODEL GUIDANCE SHOWS A
TRACE TO SEVERAL HUNDREDTHS OF AN INCH OF RAIN ACROSS THE AREA
OVERNIGHT...ALTHOUGH JUST HOW WIDESPREAD PRECIPITATION WILL BE
REMAINS IN QUESTION. WILL CONTINUE TO SHOW A 50% CHANCE OF RAIN OVER
THE ENTIRE AREA OVERNIGHT...WITH PRECIPITATION AMOUNTS GENERALLY A
FEW HUNDREDTHS OF AN INCH OR LESS (NAM/ECMWF). THE GFS REMAINS AN
OUTLIER...SHOWING 0.10-0.15". LOWS TONIGHT WILL HIGHLY DEPEND ON
WHERE AND HOW MUCH PRECIPITATION OCCURS. WHERE PRECIP DOES OCCUR...
GIVEN THE COOL/DRY SURFACE AIRMASS IN PLACE...A HYBRID CAD WEDGE
WILL DEVELOP...AND EVAP COOLING WOULD KEEPS TEMPS A FEW DEGREES
LOWER THAN AREAS WITHOUT PRECIP. GIVEN THE AFOREMENTIONED
UNCERTAINTY...AT THIS TIME WILL CONTINUE TO FOLLOW MOS GUIDANCE...
WITH LOWS RANGING FROM THE UPPER 30S IN THE NORTH TO LOWER 40S IN
THE SOUTH. -VINCENT
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 330 AM SUNDAY...
MONDAY:
THE WEAKENING SHEAR AXIS EXTENDING ENE FROM THE CENTRAL PLAINS INTO
NEW ENGLAND BY 12Z MONDAY IS PROGGED TO CONTINUE WEAKENING AS IT
PROGRESSES EAST OR ESE TOWARD THE MID-ATLANTIC ON MONDAY. THE
AFOREMENTIONED SHORTWAVE DIGGING SOUTHEAST INTO THE UPPER GREAT
LAKES BY 12Z MON IS PROGGED TO DIG INTO THE LOWER GREAT LAKES BY 00Z
TUESDAY...AND IS GENERALLY EXPECTED TO REMAIN TOO FAR NORTH TO HAVE
MUCH INFLUENCE ON CENTRAL NC DURING THE DAY MON. HOWEVER...THE SHEAR
AXIS (AND AN ASSOCIATED WEAK LOW-LEVEL TROUGH) PROGRESSING TOWARD
THE AREA SHOULD PROVIDE SUFFICIENT FORCING FOR PRECIPITATION VIA A
COMBINATION OF DPVA AND LOW/MID LEVEL ISENTROPIC LIFT. EXPECT PATCHY
DRIZZLE/LIGHT RAIN TO BE ONGOING MONDAY MORNING IN ASSOC/W
RELATIVELY WEAK ISENTROPIC LIFT...AND WILL CONTINUE TO SHOW A 50%
CHANCE OF RAIN EVERYWHERE THROUGH NOON. AFTER NOON...THE BETTER
FORCING MENTIONED ABOVE WILL ARRIVE...AND WILL INCREASE POPS TO
LIKELY (60%) GIVEN THAT MOST OF THE MODEL GUIDANCE (NAM/ECMWF) SHOWS
MEASURABLE PRECIP OVER CENTRAL NC MONDAY AFTERNOON (GFS AN OUTLIER
WITH BARELY MORE THAN A TRACE)...WITH ADDITIONAL SUPPORT FROM THE
NCEP HIGH-RES WRF-NMM WHICH SHOWS A WIDESPREAD SWATH OF RAIN
CROSSING CENTRAL NC FROM WEST-EAST BETWEEN ROUGHLY 18-00Z. HIGHS ON
MONDAY ARE DIFFICULT TO ASCERTAIN GIVEN SOME QUESTION WITH THE
LOCATION/EXTENT OF RAIN/DRIZZLE PRIOR EARLY IN THE DAY PRIOR TO THE
MORE WIDESPREAD RAIN EXPECTED IN THE AFTERNOON. REGARDLESS...EXPECT
A HYBRID OR IN-SITU CAD WEDGE TO DEVELOP...WITH HIGHS COOLER THAN IN
PREVIOUS DAYS. WILL INDICATE HIGHS RANGING FROM THE UPPER 40S N/NW
PIEDMONT TO LOWER 50S ELSEWHERE. IT IS POSSIBLE THAT HIGHS MAY NOT
EXCEED THE MID/UPPER 40S IF DRIZZLE OR LIGHT RAIN IS PREVALENT
THROUGH THE MORNING AND EARLY AFTERNOON HOURS PRIOR TO THE POTENTIAL
FOR MORE WIDESPREAD RAIN MOVING ACROSS THE AREA FROM WEST-EAST
MID/LATE AFTERNOON.
MONDAY NIGHT:
PRECIP ASSOC/W THE SHEAR AXIS AND RESULTING LOW/MID LEVEL ISENTROPIC
LIFT MON AFTERNOON SHOULD END BY 00-03Z TUE AS THE SHEAR AXIS
PROGRESSES OFFSHORE. THE AFOREMENTIONED H5 SHORTWAVE DIGGING INTO
THE LOWER GREAT LAKES DURING THE DAY MONDAY IS PROGGED TO AMPLIFY AS
IT DIGS INTO NEW ENGLAND AND THE MID-ATLANTIC BY 06Z TUE...FURTHER
AMPLIFYING AS IT PROGRESSES OFFSHORE THE MID-ATLANTIC BETWEEN
06-12Z. THIS AMPLIFYING UPPER LEVEL TROUGH WILL INITIATE
CYCLOGENESIS OFFSHORE THE CAROLINA COAST MON NIGHT AND RESULT IN A
FORMIDABLE EXTRATROPICAL CYCLONE IN THE NORTH ATLANTIC DURING THE
DAY TUE. OVER CENTRAL NC...HEIGHT/RISES SYNOPTIC SUBSIDENCE IN THE
WAKE OF THE SHEAR AXIS AND UPPER LEVEL TROUGH WILL RAPIDLY WARM/DRY
THE MID AND UPPER LEVELS AFTER 00-03Z TUE...IN ADDITION TO PRESSURE
RISES UPSTREAM IN THE OH VALLEY AND MID-ATLANTIC WHICH SHOULD HELP
FORCE A DRIER LOW-LEVEL AIRMASS INTO THE AREA BY 12Z TUE. IT IS
STILL NOT CLEAR WHETHER OR NOT THE CAD WEDGE WILL ENTIRELY SCOUR OUT
BY SUNRISE TUE. MODEL SOUNDINGS CONTINUE TO SHOW A VERY SHALLOW
SATURATED LAYER PERSISTING THROUGH 12Z TUE...AND HIGH PRESSURE
UPSTREAM OF THE AREA MAY NOT BE STRONG ENOUGH TO RESULT IN
APPRECIABLE SURFACE COLD ADVECTION TO COMPLETELY SCOUR OUT THE
WEDGE. WITH THE ABOVE IN MIND...UNCERTAINTY PERSISTS W/REGARD TO
CLOUD COVER AND LOW TEMPS. WILL SHOW AT LEAST A CLEARING TREND...
WITH LOWS RANGING FROM THE UPPER 30S TO LOWER 40S. -VINCENT
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 245 AM SUNDAY...
THE EJECTION OF THE MID-UPPER LOW FROM THE SOUTHWEST IS THE MAIN
WEATHER FEATURE TO WATCH THIS PERIOD... ALONG WITH A TURN TO COLDER
CONDITIONS LATE IN THE WEEK AND NEXT WEEKEND. OUT AHEAD OF THIS
STORM... IT WILL BECOME VERY MILD TO WARM AGAIN WITH TEMPERATURES
AVERAGING 10-15 DEGREES ABOVE THE 30 YEAR NORMALS.
THE MID-UPPER LOW IS ALREADY CUT OFF FROM THE MAIN WESTERLIES AND
THIS FAVORS THE MORE SOUTHERN AND SLOWER FORECASTS THAT THE NEW
EUROPEAN MODEL SUITE INDICATES. HOWEVER... NEARLY ALL MODEL GUIDANCE
INDICATES A FAIRLY SIMILAR SYSTEM WILL AFFECT OUR REGION CENTERED
AROUND WED-WED NIGHT... BUT THE TRACK IS OF CONCERN AS SOME MODELS
TRACK THE MID LEVEL CIRCULATION OVERHEAD... SOME TO OUR NW AND SOME
TO OUR SE. THE EXACT TRACK WILL DICTATE MANY ASPECTS OF THE SYSTEM
FOR OUR REGION... INCLUDING QPF/THUNDER CHANCES/TEMPS. FOR NOW... WE
WILL MAINTAIN OUR CURRENT FORECASTS... AND INCORPORATE A SLIGHTLY
SLOWER AND EVEN MORE MOIST SYSTEM PER THE LATEST EUROPEAN MODEL. IN
ADDITION... IF THE EUROPEAN TRACK VERIFIES... WE WOULD GE A
SIGNIFICANT RAIN WITH 1 TO 1.5 INCHES ACROSS THE REGION.
AFTER THE SYSTEM PASSES... IT WILL TURN COLDER... BUT REALLY NOT
UNTIL FRIDAY WHEN THE MAIN PUSH OF CAA IS EXPECTED. THERE IS STILL
QUITE A BIT OF DIFFERENCES IN THE MODEL FORECASTS AFTER FRIDAY WITH
THE CANADIAN INDICATING ANOTHER SOUTHERN BRANCH SYSTEM. MORE ON THIS
LATER.
SENSIBLE WEATHER HIGHLIGHTS... TUESDAY... SOME MORNING DRIZZLE...
BECOMING PARTLY CLOUDY AND WARMING INTO THE 60S. WEDNESDAY...
PERIODS OF RAIN WITH HIGHS 55-65. THURSDAY... RAIN ENDING. PARTLY
CLOUDY. HIGHS IN THE 60S. FRIDAY... TURNING COLDER AND BREEZY. HIGHS
IN THE 50S.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 645 AM SUNDAY...
24-HR TAF PERIOD:
VFR CONDITIONS ARE EXPECTED TO PREDOMINATE THROUGH ~00Z THIS
EVENING...WITH CONDITIONS DETERIORATING THEREAFTER. A BACKDOOR COLD
FRONT WILL PROGRESS SOUTH THROUGH CENTRAL NC THIS MORNING BEFORE
STALLING OUT JUST SOUTH OF THE AREA THIS AFTERNOON. VFR CEILINGS IN
THE 4-7 KFT RANGE ARE EXPECTED TO PREDOMINATE THIS AFTERNOON. BY OR
SHORTLY AFTER 00Z...LOW-LEVEL (925-850 MB) FLOW WILL ASSUME MORE OF
A SOUTHERLY COMPONENT...RESULTING IN OVERRUNNING AND THE DEVELOPMENT
OF MVFR CEILINGS AND AREAS OF LIGHT RAIN...WITH A POTENTIAL FOR
CONDITIONS TO FURTHER DETERIORATE TO IFR AND POSSIBLY LIFR BY 12Z
MON. WHETHER OR NOT IFR/LIFR CONDITIONS DEVELOP PRIOR TO 12Z MON
WILL HEAVILY DEPEND ON WHETHER OR NOT MEASURABLE PRECIPITATION
DEVELOPS AND PERSISTS IN VICINITY OF THE TAF SITES.
LOOKING AHEAD:
CONDITIONS ARE EXPECTED TO FURTHER DETERIORATE TO IFR AND
POTENTIALLY LIFR OVER CENTRAL NC ON MONDAY AS PRECIPITATION FALLING
INTO THE INITIALLY COOL/DRY AIRMASS IN PLACE RESULTS IN THE
DEVELOPMENT OF A COLD AIR DAMMING WEDGE. SOME UNCERTAINTY PERSISTS
W/REGARD TO THE STRENGTH OF THE CAD WEDGE AND WHETHER OR NOT
CEILINGS WILL BECOME IFR/LIFR OR REMAIN MVFR OR BORDERLINE IFR. IF
WIDESPREAD LIGHT RAIN DEVELOPS TONIGHT AND PERSISTS INTO MONDAY...
THEN THE IFR/LIFR SCENARIO WOULD BE MORE LIKELY. CONVERSELY...IF
PRECIPITATION IS INTERMITTENT AND PATCHY...THEN MVFR OR BORDERLINE
IFR CEILINGS WOULD BE MORE LIKELY. CONDITIONS ARE EXPECTED TO
IMPROVE TO VFR EITHER LATE MONDAY NIGHT OR SHORTLY AFTER SUNRISE
TUESDAY AS DRY HIGH PRESSURE BUILDS BACK INTO THE AREA FROM THE
WEST/NW. HOWEVER...VFR CONDITIONS WILL BE SHORT-LIVED AS A POTENT
UPPER LEVEL LOW AND ASSOCIATED SFC LOW PRESSURE SYSTEM ARE PROGGED
TO TRACK OVER THE CAROLINAS/VA MID-WEEK. EXPECT CONDITIONS TO
DETERIORATE TUE NIGHT...WITH WIDESPREAD RAIN AND SUB-VFR CONDITIONS
DURING THE DAY WED...FOLLOWED BY A RETURN TO VFR CONDITIONS IN THE
WAKE OF A COLD FRONTAL PASSAGE WED EVE/NIGHT. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT/GIH
NEAR TERM...HARTFIELD/VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
952 AM CST SUN JAN 8 2012
.UPDATE...
FORECAST LOOKS ON TRACK OVERALL. INVERTED SURFACE TROUGH/STALLED
OLD FRONT REMAIN ANCHORED OVER FAR EASTERN COUNTIES THIS MORNING.
PATCHY DENSE FOG HAS FORMED ALONG/NORTH OF I-20 AND MAINLY EAST OF
I-35W THIS MORNING. CONDITIONS SHOULD IMPROVE THROUGH MIDDAY WITH
NORTH WINDS INCREASING TO NEAR 10 MPH THIS AFTERNOON. WE WILL
HANDLE ANY FOG SHORT TERM FORECASTS...VERSUS A FULL PACKAGE UPDATE.
EXTENSIVE CLOUD COVER EXISTS WHICH WILL KEEP TEMPERATURES COOL
THROUGHOUT DAY. CURRENT HIGHS LOOK REPRESENTATIVE WITH A SMALL
DIURNAL RISE IN TEMPERATURES EXPECTED TODAY. HAVE LEFT SLIGHT
CHANCES OF RAIN FOR LATER THIS AFTERNOON WELL SOUTH OF I-20 WHERE
ISENTROPIC ASCENT SHOULD BEGIN IN EARNEST BY THIS EVENING.
WILL ONLY SEND MATRIX AND IMAGE PRODUCT UPDATES THIS MORNING.
05/
&&
.AVIATION...
STRATUS REMAINS JUST NORTH OF THE DALLAS-FORT WORTH METRO AREA
TERMINALS EARLY THIS MORNING. LATEST HRRR GUIDANCE SLOWLY ADVECTS
CLOUDS SOUTH OVER THE AREA. RECENT BREAKS IN THE HIGH CLOUDS
REVEAL A SLIGHT SOUTHWARD EXPANSION OF THE CLOUD DECK WITH TIME ON
11-3.9 MICRON LOOP. AS A RESULT...WILL CONTINUE WITH THE
INTRODUCTION OF MVFR CIGS TO MAJOR AIRPORTS...BUT PUSH BACK TIMING
TO 14-15Z. IF AND WHEN STRATUS SINK FAR ENOUGH SOUTH TO COVER
METRO AREA TAF SITES...FEEL IT WILL HAVE A HARD TIME ERODING AS
OVERRUNNING WILL INCREASE LATER TODAY FURTHER TRAPPING THE
MOISTURE BENEATH THE INVERSION. THERE MAY BE SOME BREAKS DURING PEAK
HEATING HOURS THIS AFTERNOON BUT FEEL THIS WOULD BE SHORT LIVED IF
AT ALL. EXPECT CLOUDS TO LOWER AND RAIN TO BEGIN AREA WIDE AROUND OR
SHORTLY AFTER MIDNIGHT LOCAL AS ISENTROPIC LIFT CONTINUES TO
INCREASE...AND WILL CONSEQUENTLY SHOW IFR CIGS AND PREDOMINANT
LIGHT RAIN AFTER 06Z. ISOLATED THUNDERSTORMS ARE POSSIBLE BY
MONDAY MORNING...WILL NOT INCLUDE TS IN TAFS AT THIS TIME AS
COVERAGE SHOULD BE LOW AND EXACT TIMING OF CONVECTION WOULD BE
MUCH BETTER RECOGNIZED LATER TODAY AND TONIGHT AS NEW MODEL DATA
IS RECEIVED.
30
&&
.PREV DISCUSSION... /ISSUED 417 AM CST SUN JAN 8 2012/
UNSETTLED WEATHER WILL PREVAIL ACROSS NORTH TEXAS THE NEXT FEW
DAYS AS ENERGY FROM A DEEP UPPER TROUGH INTERACTS WITH LOW LEVEL
MOISTURE ABOVE A WEDGE OF COOL AIR AT THE SURFACE. TODAY WILL BE
CLOUDY AND COOL ACROSS NORTH TEXAS WITH AFTERNOON MAINLY IN THE
50S. A FEW SHOWERS MAY DEVELOP IN THE SOUTHEAST LATE THIS
AFTERNOON AS LIFT INCREASES OVER A STALLED COLD FRONT OVER SOUTH
TEXAS. UPPER LEVEL DIFFLUENCE WILL SET UP TONIGHT AS THE CLOSED
LOW ROTATES INTO FAR WEST TEXAS. RAIN CHANCES WILL BE ON THE
INCREASE THROUGH THE NIGHT AND INTO MONDAY WITH INCREASING
ISENTROPIC LIFT AND LARGE SCALE FORCING. MID LEVEL LAPSE RATES
SHOULD BE SUFFICIENT TO SUPPORT ISOLATED THUNDERSTORMS ACROSS THE
ENTIRE REGION. THE CORE OF THE UPPER LOW IS PROGGED TO TRACK
ACROSS THE NORTHERN HALF OF NORTH TEXAS MONDAY NIGHT THROUGH
TUESDAY. RAIN CHANCES SHOULD CONTINUE ACROSS THE ENTIRE REGION AND
THE RAIN MAY MIX WITH SOME LIGHT SNOW ACROSS THE WESTERN COUNTIES
MAINLY MONDAY NIGHT/TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED AT THIS TIME AS SURFACE TEMPERATURES SHOULD REMAIN ABOVE
FREEZING. IT APPEARS THAT THE BETTER CHANCES FOR SNOW WILL BE
ACROSS PORTIONS OF THE CONCHO VALLEY AND BIG COUNTRY WHERE DEEPER
COLD AIR IS EXPECTED. PRECIPITATION CHANCES WILL LINGER THROUGH
TUESDAY AFTERNOON...ESPECIALLY ALONG THE RED RIVER...NEAR THE
TRACK OF THE UPPER LOW. ALL PRECIPITATION WILL END TUESDAY EVENING
AS DRY AND SUBSIDENT AIR MOVES IN BEHIND THE DEPARTING SYSTEM.
THIS IS STILL SHAPING UP TO BE A GOOD PRECIPITATION PRODUCER FOR
NORTH TEXAS WITH AVERAGE RAINFALL TOTALS ON THE ORDER OF ONE TO
TWO INCHES.
THE FORECAST FOR THE MIDDLE OF THE WEEK THROUGH THE WEEKEND WILL
BE CHALLENGING TO SAY THE LEAST AS THE EXTENDED MODELS ARE NOT IN
AGREEMENT WITH REGARDS TO THE FATE OF ANOTHER SOUTHERN STREAM
TROUGH FORECAST TO DEVELOP OFF THE WEST COAST. THE ONE THING THAT
ALL THE GUIDANCE IS IN AGREEMENT ON IS THAT A STRONG COLD FRONT
WILL MOVE ACROSS THE REGION WEDNESDAY NIGHT THROUGH THURSDAY AS A
HIGH AMPLITUDE RIDGE BUILDS OFF THE WEST COAST. THE GFS AND
CANADIAN SOLUTIONS ARE VERY PROGRESSIVE AND BRING THE UPPER TROUGH
ACROSS NORTH TEXAS RIGHT AFTER THE COLD AIR MOVES IN WHICH WOULD
RESULT IN SOME WINTER PRECIP FOR PORTIONS OF NORTH TEXAS. THE
ECMWF AND 06Z DGEX SOLUTIONS CUT THE UPPER LOW OFF FROM THE MEAN
FLOW AND DO NOT BRING IT ACROSS TEXAS UNTIL LATE SATURDAY OR
SUNDAY. FOR NOW WE HAVE OPTED FOR THE DRIER AND SLOWER ECMWF AND
DGEX SOLUTIONS BASED ON PATTERN RECOGNITION. WE WILL HAVE TO WATCH
THIS SYSTEM CLOSELY IN THE COMING DAYS SINCE IT HAS POTENTIAL TO
CAUSE SOME IMPACTS LATE IN THE WEEK.
OTHERWISE...EXPECT A COOLER WEEK THAN THE FIRST WEEK OF JANUARY WITH
HIGHS MAINLY IN THE 40S AND 50S AND LOWS GENERALLY IN THE 30S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 54 43 48 41 49 / 10 80 100 70 30
WACO, TX 58 46 52 36 53 / 20 90 100 50 20
PARIS, TX 57 42 50 46 53 / 10 70 100 90 50
DENTON, TX 53 39 45 39 49 / 10 70 90 80 30
MCKINNEY, TX 55 42 49 41 49 / 10 70 100 80 40
DALLAS, TX 55 44 49 42 49 / 10 80 100 70 30
TERRELL, TX 58 45 52 42 52 / 10 80 100 80 30
CORSICANA, TX 60 49 56 40 52 / 20 90 100 70 30
TEMPLE, TX 58 46 51 38 56 / 20 90 100 40 20
MINERAL WELLS, TX 53 37 42 35 47 / 10 70 90 60 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
30/05
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
533 AM CST SUN JAN 8 2012
.AVIATION...
STRATUS REMAINS JUST NORTH OF THE DALLAS-FORT WORTH METRO AREA
TERMINALS EARLY THIS MORNING. LATEST HRRR GUIDANCE SLOWLY ADVECTS
CLOUDS SOUTH OVER THE AREA. RECENT BREAKS IN THE HIGH CLOUDS
REVEAL A SLIGHT SOUTHWARD EXPANSION OF THE CLOUD DECK WITH TIME ON
11-3.9 MICRON LOOP. AS A RESULT...WILL CONTINUE WITH THE
INTRODUCTION OF MVFR CIGS TO MAJOR AIRPORTS...BUT PUSH BACK TIMING
TO 14-15Z. IF AND WHEN STRATUS SINK FAR ENOUGH SOUTH TO COVER
METRO AREA TAF SITES...FEEL IT WILL HAVE A HARD TIME ERODING AS
OVERRUNNING WILL INCREASE LATER TODAY FURTHER TRAPPING THE
MOISTURE BENEATH THE INVERSION. THERE MAY BE SOME BREAKS DURING PEAK
HEATING HOURS THIS AFTERNOON BUT FEEL THIS WOULD BE SHORT LIVED IF
AT ALL. EXPECT CLOUDS TO LOWER AND RAIN TO BEGIN AREA WIDE AROUND OR
SHORTLY AFTER MIDNIGHT LOCAL AS ISENTROPIC LIFT CONTINUES TO
INCREASE...AND WILL CONSEQUENTLY SHOW IFR CIGS AND PREDOMINANT
LIGHT RAIN AFTER 06Z. ISOLATED THUNDERSTORMS ARE POSSIBLE BY
MONDAY MORNING...WILL NOT INCLUDE TS IN TAFS AT THIS TIME AS
COVERAGE SHOULD BE LOW AND EXACT TIMING OF CONVECTION WOULD BE
MUCH BETTER RECOGNIZED LATER TODAY AND TONIGHT AS NEW MODEL DATA
IS RECEIVED.
30
&&
.PREV DISCUSSION... /ISSUED 417 AM CST SUN JAN 8 2012/
UNSETTLED WEATHER WILL PREVAIL ACROSS NORTH TEXAS THE NEXT FEW
DAYS AS ENERGY FROM A DEEP UPPER TROUGH INTERACTS WITH LOW LEVEL
MOISTURE ABOVE A WEDGE OF COOL AIR AT THE SURFACE. TODAY WILL BE
CLOUDY AND COOL ACROSS NORTH TEXAS WITH AFTERNOON MAINLY IN THE
50S. A FEW SHOWERS MAY DEVELOP IN THE SOUTHEAST LATE THIS
AFTERNOON AS LIFT INCREASES OVER A STALLED COLD FRONT OVER SOUTH
TEXAS. UPPER LEVEL DIFFLUENCE WILL SET UP TONIGHT AS THE CLOSED
LOW ROTATES INTO FAR WEST TEXAS. RAIN CHANCES WILL BE ON THE
INCREASE THROUGH THE NIGHT AND INTO MONDAY WITH INCREASING
ISENTROPIC LIFT AND LARGE SCALE FORCING. MID LEVEL LAPSE RATES
SHOULD BE SUFFICIENT TO SUPPORT ISOLATED THUNDERSTORMS ACROSS THE
ENTIRE REGION. THE CORE OF THE UPPER LOW IS PROGGED TO TRACK
ACROSS THE NORTHERN HALF OF NORTH TEXAS MONDAY NIGHT THROUGH
TUESDAY. RAIN CHANCES SHOULD CONTINUE ACROSS THE ENTIRE REGION AND
THE RAIN MAY MIX WITH SOME LIGHT SNOW ACROSS THE WESTERN COUNTIES
MAINLY MONDAY NIGHT/TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED AT THIS TIME AS SURFACE TEMPERATURES SHOULD REMAIN ABOVE
FREEZING. IT APPEARS THAT THE BETTER CHANCES FOR SNOW WILL BE
ACROSS PORTIONS OF THE CONCHO VALLEY AND BIG COUNTRY WHERE DEEPER
COLD AIR IS EXPECTED. PRECIPITATION CHANCES WILL LINGER THROUGH
TUESDAY AFTERNOON...ESPECIALLY ALONG THE RED RIVER...NEAR THE
TRACK OF THE UPPER LOW. ALL PRECIPITATION WILL END TUESDAY EVENING
AS DRY AND SUBSIDENT AIR MOVES IN BEHIND THE DEPARTING SYSTEM.
THIS IS STILL SHAPING UP TO BE A GOOD PRECIPITATION PRODUCER FOR
NORTH TEXAS WITH AVERAGE RAINFALL TOTALS ON THE ORDER OF ONE TO
TWO INCHES.
THE FORECAST FOR THE MIDDLE OF THE WEEK THROUGH THE WEEKEND WILL
BE CHALLENGING TO SAY THE LEAST AS THE EXTENDED MODELS ARE NOT IN
AGREEMENT WITH REGARDS TO THE FATE OF ANOTHER SOUTHERN STREAM
TROUGH FORECAST TO DEVELOP OFF THE WEST COAST. THE ONE THING THAT
ALL THE GUIDANCE IS IN AGREEMENT ON IS THAT A STRONG COLD FRONT
WILL MOVE ACROSS THE REGION WEDNESDAY NIGHT THROUGH THURSDAY AS A
HIGH AMPLITUDE RIDGE BUILDS OFF THE WEST COAST. THE GFS AND
CANADIAN SOLUTIONS ARE VERY PROGRESSIVE AND BRING THE UPPER TROUGH
ACROSS NORTH TEXAS RIGHT AFTER THE COLD AIR MOVES IN WHICH WOULD
RESULT IN SOME WINTER PRECIP FOR PORTIONS OF NORTH TEXAS. THE
ECMWF AND 06Z DGEX SOLUTIONS CUT THE UPPER LOW OFF FROM THE MEAN
FLOW AND DO NOT BRING IT ACROSS TEXAS UNTIL LATE SATURDAY OR
SUNDAY. FOR NOW WE HAVE OPTED FOR THE DRIER AND SLOWER ECMWF AND
DGEX SOLUTIONS BASED ON PATTERN RECOGNITION. WE WILL HAVE TO WATCH
THIS SYSTEM CLOSELY IN THE COMING DAYS SINCE IT HAS POTENTIAL TO
CAUSE SOME IMPACTS LATE IN THE WEEK.
OTHERWISE...EXPECT A COOLER WEEK THAN THE FIRST WEEK OF JANUARY WITH
HIGHS MAINLY IN THE 40S AND 50S AND LOWS GENERALLY IN THE 30S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 56 43 48 41 49 / 10 80 100 70 30
WACO, TX 57 46 52 36 53 / 20 90 100 50 20
PARIS, TX 57 42 50 46 53 / 10 70 100 90 50
DENTON, TX 53 39 45 39 49 / 10 70 90 80 30
MCKINNEY, TX 55 42 49 41 49 / 10 70 100 80 40
DALLAS, TX 57 44 49 42 49 / 10 80 100 70 30
TERRELL, TX 55 45 52 42 52 / 10 80 100 80 30
CORSICANA, TX 59 49 56 40 52 / 20 90 100 70 30
TEMPLE, TX 58 46 51 38 56 / 20 90 100 40 20
MINERAL WELLS, TX 52 37 42 35 47 / 10 70 90 60 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
30/79
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1140 PM CST SAT JAN 7 2012
.AVIATION...
VFR SHOULD PREVAIL THROUGH THE OVERNIGHT HOURS. LIFR CIGS HAVE
DEVELOPED NORTHEAST OF THE METROPLEX...AND THERE IS STILL LITTLE
CONFIDENCE ON WHETHER THESE CIGS WILL REMAIN NORTHEAST OF THE TAF
SITES OR MOVE INTO THE AREA AROUND SUNRISE. HRRR REMAINS
PESSIMISTIC WHILE THE RUC LIFTS THEM NORTH. WILL STILL MAINTAIN A
MENTION OF BKN020 IN THE TAFS FOR TOMORROW MORNING TO ACCOUNT FOR
THE POSSIBILITY THAT THESE CLOUDS OR SOME OF THIS LOW LEVEL
MOISTURE MAY SPILL INTO THE METRO TAF SITES. IF CIGS DO MAKE IT
INTO THE METROPLEX...MVFR WOULD LIKELY PREVAIL ALL DAY.
THE MORE CERTAIN PART OF THE FORECAST COMES TOMORROW EVENING WHEN
INCREASING LIFT AHEAD OF THE NEXT SYSTEM SHOULD RESULT IN MVFR
PREVAILING AFTER 0Z. CIG SHOULD LOWER SUNDAY EVENING TO IFR BY 6Z
MONDAY. SHOWERS WILL BEGIN TO DEVELOP IN THE EVENING AND INCREASE
IN COVERAGE. WILL CARRY LIGHT RAIN FOR THE 24-30HR PERIOD OF THE
DFW TAF.
IT IS AN EASIER FORECAST FOR WACO. VFR WILL PREVAIL BUT VFR CIGS
NEAR 3500FT WILL DEVELOP TONIGHT AND CONTINUE THROUGH TOMORROW.
CIGS WILL LOWER SUNDAY EVENING TO MVFR...WITH SOME SHOWERS IN THE
VICINITY.
TR.92
&&
.UPDATE...
SURFACE FRONT HAS COMPLETELY PUSHED THROUGH THE EASTERN COUNTIES
OF THE CWA NOW WITH LIGHT WINDS LESS THAN 5 MPH ACROSS MOST OF THE
REGION. SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT BUT START TO
INCREASE FROM THE NORTH BY DAYBREAK AS ANOTHER SURFACE HIGH MOVES
ACROSS THE PLAINS. SURFACE DEWPOINTS ARE NOT EXPECTED TO CHANGE
MUCH OVERNIGHT THUS KEEPING WARMER OVERNIGHT LOWS IN THE 40S
ACROSS THE EASTERN COUNTIES WHILE THE WESTERN COUNTIES COOL INTO
THE 30S AGAIN. DENSE HIGH CLOUD COVER IS OVERSPREADING THE REGION
FROM THE SOUTHWEST...AHEAD OF THE UPPER LEVEL TROUGH NOW DIGGING
INTO ARIZONA. DESPITE THE LIGHT WINDS...THINK THE DENSE CLOUD
COVER WILL PREVENT FOG FROM DEVELOPING OVER THE EASTERN HALF OF
THE REGION /WHERE HIGHER DEWPOINTS WILL REMAIN/ AND HAVE REMOVED
THE MENTION OF THE FOG FROM THE FORECAST. LOW CLOUD COVER WILL
LIKELY CONTINUE TO PERSIST OVER THE NORTHEASTERN AND NORTHERN
COUNTIES OF NORTH TEXAS. ALSO FOR THE UPDATE...DID ADJUST
OVERNIGHT LOWS IN SEVERAL LOCATIONS BASED ON THE LATEST
TEMPERATURE TRENDS AND CHANGES TO THE DEWPOINTS DURING THE
OVERNIGHT PERIOD.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 321 PM CST SAT JAN 7 2012/
THE WEAK COLD FRONT HAS SLOWED DRAMATICALLY ACROSS EAST TEXAS AND
OUR THE SOUTHEAST COUNTIES TODAY WITH MINIMAL PRESSURE RISES BEHIND
THE FRONT. A WEAK INVERTED TROUGH IN THE 925-850MB LAYER HAS BEEN
NEARLY STATIONARY AS WELL OVER THE I-35 CORRIDOR/RED RIVER VALLEY
ALL DAY. THIS HAS RESULTED IN WEAK ISENTROPIC ASCENT THAT IS
HOLDING STRATUS OVER NORTHERN COUNTIES AND MAKING THE FORECAST
DIFFICULT WITH REGARD TO CLOUD COVER AND TEMPERATURES. MEANWHILE
AN UPPER DISTURBANCE CONTINUES TO INTENSIFY AND DEEPEN OVER THE
CENTRAL ROCKIES.
THE HRRR/WRF AND RUC BAK40 SOUNDINGS ALL INDICATE AT LEAST SOME
POTENTIAL FOR FOG DEVELOPING OVERNIGHT WITH WINDS BECOMING LIGHT
AND A TIGHT MOISTURE GRADIENT UP THROUGH THE BOUNDARY LAYER
THROUGH MIDDAY SUNDAY. WE ARE INSERTING PATCHY FOG EAST OF A
BOWIE...MINERAL WELLS...KILLEEN LINE WITH MORE COVERAGE OF LIGHT
FOG ACROSS THE NORTHEAST COUNTIES. TOO DIFFICULT TO ASCERTAIN IF
ANY FOG WILL BE DENSE AT THIS TIME. ANY FOG SHOULD DISSIPATE BY
AFTERNOON AS NORTH WINDS MIX TO AROUND 10 MPH OR SLIGHTLY HIGHER
THOUGH SOUTHEAST COUNTIES WILL HAVE LIGHTER NORTHEAST WINDS.
ISENTROPIC LIFT BEGINS OVER THE STALLED FRONTAL BOUNDARY SUNDAY
AFTERNOON IN DEVELOPING WAA REGIME ACROSS OUR SOUTHEAST COUNTIES.
THE ROCKIES DISTURBANCE WILL DEEPEN AND CLOSE OFF OVER AZ/NM AS
WELL. LIGHT RAIN SHOULD SLOWLY DEVELOP ACROSS THE SOUTHEAST BY
AFTERNOON...THEN OVERSPREAD NORTH TEXAS SUNDAY NIGHT AND MONDAY
AS ISENTROPIC ASCENT INCREASES WITH PLENTY OF FETCH FROM THE GULF
OF MEXICO. A GOOD STEADY RAIN IS EXPECTED INTO MONDAY EVENING.
1-2 INCHES OF BENEFICIAL RAINFALL WILL LIKELY OCCUR OVER THE FULL
DURATION WITH ISOLATED AMOUNTS IN EXCESS OF 3 INCHES POSSIBLE
ACROSS FAR SOUTHEASTERN AREAS. HAVE MAINTAINED ISOLATED/EMBEDDED
THUNDERSTORMS WITH LARGE-SCALE LIFT INTENSIFYING AND LAPSE RATES
ALOFT INCREASING TO NEAR 7 DEG/C.
THE UPPER LOW SLIDES OVER WEST TX BY MONDAY EVENING...THEN MODELS
CONTINUE TO DIVERGE ON ACTUAL STRENGTH/TRACK MONDAY NIGHT AND TUESDAY.
WILL USE A MEAN OF THE TRACKS WITH COLDEST AIR ALOFT TRACKING
ACROSS AREAS JUST NORTHWEST OF THE DFW METROPLEX. WITH THIS IN
MIND...A RAIN/SNOW SHOWER MIX COULD OCCUR WITH DYNAMIC COOLING AND
COLDER SURFACE TEMPERATURES ACROSS THE HIGHER TERRAIN OF THE
WESTERN COUNTIES. BOTH SURFACE AND GROUND TEMPERATURES WILL
REMAIN WELL ABOVE FREEZING BUT PROFILES ALOFT MAY SUPPORT SOME
SNOW MIXING IN WITH THE RAIN. IF ANY MINOR ACCUMULATIONS WERE TO
OCCUR...IT WOULD BE MINOR AND BRIEF ON ELEVATED SURFACES OR
GRASSY AREAS. DETAILS REMAIN FUZZY WE DO NOT EXPECT A MAJOR
WINTER EVENT WITH THIS SYSTEM. A DRY NOSE DOES APPEAR TO ARRIVE
TUESDAY FROM THE SOUTHWEST AND GET INGESTED INTO THE SYSTEM WITH
PRECIPITATION CHANCES LOWERING QUICKLY FROM SOUTH TO NORTH AS THE
UPPER LOW LIFTS TOWARD THE OZARKS AND MISSISSIPPI VALLEY BY
TUESDAY NIGHT.
A STRONGER COLD FRONT TAPPING AIR FROM ALASKA AND WESTERN CANADA
ARRIVES THURSDAY/FRIDAY A STEEP UPPER RIDGE ACROSS THE WESTERN
STATES AND A DEEP TROUGH OVER THE GREAT LAKES AND MISSISSIPPI
VALLEY. MEANWHILE...THE GFS AND ECMWF AS SWAPPED SOLUTIONS
REGARDING A POSSIBLE SOUTHERN PIECE OF ENERGY MOVING ACROSS RIGHT
AROUND THAT TIME FRAME. FOR NOW...WE ARE MAINTAINING A DRY...BRISK
AND COLD FORECAST AND UNDERCUTTING MOS TEMPERATURES BY A GOOD 5
DEGREES OR MORE PER PATTERN RECOGNITION. IT IS POSSIBLE THAT HIGHS
MAY NEED TO BE LOWERED IN UPCOMING FORECASTS IF IT BECOMES EVIDENT
THAT THIS IS TRUE ARCTIC AIR ORIGIN.
WE WILL CONTINUE TO FINE TUNE THE LATE WEEK FORECAST ONCE WE GET
PAST OUR FIRST SYSTEM FOR THE EARLY PART OF THE WEEK.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 43 57 44 46 40 / 0 10 80 100 70
WACO, TX 41 63 46 49 39 / 0 20 90 100 50
PARIS, TX 46 56 43 51 40 / 5 20 70 100 90
DENTON, TX 41 55 39 44 38 / 5 10 70 90 80
MCKINNEY, TX 42 57 41 47 39 / 5 10 70 100 80
DALLAS, TX 44 58 45 47 41 / 0 10 80 100 70
TERRELL, TX 43 58 46 50 40 / 5 20 80 100 80
CORSICANA, TX 44 61 48 53 41 / 5 20 90 100 70
TEMPLE, TX 40 65 46 49 39 / 0 20 90 100 40
MINERAL WELLS, TX 36 57 37 42 36 / 0 10 70 90 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
539 PM PST Mon Jan 9 2012
.SYNOPSIS...A storm system will move through the Inland Northwest
Monday night and early Tuesday, with a chance of precipitation
across most of the region. High pressure will build into the
region starting late Tuesday, with dry conditions and cooler
temperatures through the end of the work week. However watch for
some patchy morning fog in the more sheltered locations and near
bodies of water. There is the potential for more precipitation by
next weekend.
&&
.DISCUSSION...
GFS fm 18Z, latest HRRR and trends in satellite and radar strongly
suggets preipitation will start over the Okanogan Hoghlands, NE
Mountains and the Northern Panhandle between 01Z and 03Z. Updated
the forecasts to reflect this, including higher pops and QPF.
Still not expecting significant valley accumulations. JL
&&
.AVIATION...
00Z TAFS: A weak frontal boundary will move east of the Cascades
this evening with a band of rain/snow developing and enhancing over
the Idaho Panhandle overnight with the assistance from upslope
flow. Of most concern is the 0-6z period at KMWH where cold air
remains trapped with temperatures near 32F. The passing front could
bring a brief rise in temperature to above freezing but soundings do
not indicate much mixing potential and thus put in a TEMPO group for
-FZRA. Elsewhere the lower levels are warmer over Eastern WA and
North Idaho with -RA or -RASN expected. Low level upslope flow in
combination with precipitation will moisten the low levels with
IFR/MVFR stratus expected to increase between 6-12z Tuesday. Dry
air advection behind the front will increase 12-18z Tuesday with
stratus expected to lift and become scattered by afternoon. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 33 18 28 19 28 / 70 10 0 0 0 0
Coeur d`Alene 29 35 17 31 18 29 / 80 10 0 0 0 0
Pullman 31 37 21 31 23 33 / 80 30 0 0 0 0
Lewiston 33 40 23 34 23 35 / 80 40 0 0 0 0
Colville 27 33 13 28 17 33 / 60 10 0 0 0 0
Sandpoint 30 34 16 28 17 30 / 80 10 0 0 0 0
Kellogg 29 35 20 28 18 29 / 90 30 0 0 0 0
Moses Lake 29 36 17 31 19 30 / 20 0 0 0 0 0
Wenatchee 28 35 22 29 20 32 / 10 0 0 0 0 0
Omak 27 31 14 29 16 31 / 10 10 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
358 PM PST Mon Jan 9 2012
.SYNOPSIS...A storm system moves through the Inland Northwest
Monday night and Tuesday, with a chance of precipitation across
most of the region. The highest threat will be near the Cascades
and across the Blue Mountains, the Palouse and Idaho Panhandle
tonight, before decreasing from the west through Tuesday. High
pressure builds into the region starting late Tuesday, with dry
conditions and cooler temperatures through the end of the work
week. However watch for some patchy fog morning in the more
sheltered locations and near bodies of water. There is the
potential for more precipitation by next weekend.
&&
.DISCUSSION...
Tonight and Tomorrow...Front with weakening and elongating
subtropical moisture feed into it sags through Eastern Washington
and Northern Idaho tonight and exits to the southeast tomorrow.
The fact that the moisture feed is so narrow and appears to be
weakening as well as models showing a low spinning up along the
feed off the Northern California coast and further weakening the
feed continues to suggest the current course of action which is to
keep moderate to high pops but low precipitation and snow amounts
associated with the passage of this system. Kicker trof behind it
moves in with a drier and cooler northwest flow which allows for
an increase in wind and clearing conditions along with a cooling
trend apparent in forecast highs for tomorrow. Still some
uncertainty remains as latest HRRR model depicts a very elongated
and likely convectively enhanced band of precipitation forming
further north and west than what is depicted in the forecast but
still takes propagates it in the same general northwest to
southeast direction. /Pelatti
Tuesday night through Thursday: A shortwave trough exits early as
a ridge of high pressure builds in, bringing generally dry
conditions, occasional cloudy periods and cooler than normal
temperatures. On Tuesday evening the shortwave system moves toward
the High Plains. Save for the boundary layer, the atmosphere dries
out in the northwesterly flow behind it. A chance of snow showers
will linger around the central Panhandle in the evening but
otherwise dry weather is expected. Breezy conditions are expected
in the evening, then incoming high pressure will allow gradients
to slacken and winds to subside. How much the evening winds are
able to dry out the boundary layer will impact the potential for
stratus and fog overnight and Wednesday morning. The best chances
will be in the sheltered mountain valleys (from the Cascades
through the Selkirks and Central Panhandle Mountains) as well as
in the L-C valley. Fog is also a risk around the deeper basin, the
Long Lake and the Spokane River, as well as West Plains area;
however the moisture appears shallower and fog may be less
persistent here.
Going into Wednesday night and Thursday models track a couple
upper level disturbances across the region. With little deep
moisture and no strong connection to the surface, these
disturbances are expected to pass without any precipitation.
However look for increased middle to high level clouds. Fog and
stratus will once again be a threat Wednesday night and Thursday
morning, however coverage is expected to be less with the
aforementioned middle and high clouds. How thick or persistent or
widespread these clouds are will impact the potential for fog.
They will also impact temperatures.
Temperatures are expected to drop below normal through this
period, as cooler air invades from the north-northwest behind
Tuesday`s wave. With light winds and drier air coming in,
nighttime lows are expected to drop in the teens to low 20s, with
some single digits possible around the Cascades and northern
mountains. Afternoon highs are expected to be in the 20s and low
30s, with some teens in the mountains. Expect some moderation on
Thursday as compared to Wednesday. Overall values are projected to
be around 5 degrees or so below average. Precise numbers will be
impacted by the cloud and/or fog coverage; if more persistent cloud
cover develops, overnights lows may be too cool. /J. Cote`
Thursday night through Monday...Models are indicating a potential
pattern change towards the end of the extended period. The upper
ridge over the area is expected to flatten with a high amplitude
ridge developing between 150-160W out in the Eastern Pacific. This
would allow a cold trough in the Gulf of Alaska to drop southeast
towards Washington and North Idaho Sunday and Monday. The 12z and
00z runs of the ECMWF, Canadian, and UKMET extension favor this
with about half of the GFS Ensemble members also in support. Thus
the milder 12z GFS solution with trying to hold onto more ridging is
not as likely to pan out. But given the tendency for the ridge
this fall and winter, the 12z GFS can not be ruled out.
The Inland Northwest will be under generally dry zonal flow Friday
and Saturday with near normal temperatures. And then as the trough
drops over the area Sunday and Monday with 850mb temps cooling in
the -5 to -10C range...temperatures will lower to below normal
readings by Monday. The flow aloft remains westerly Sunday and
Monday so best potential for snow showers will be in the
mountains. JW
&&
.AVIATION...
00Z TAFS: A weak frontal boundary will move east of the Cascades
this evening with a band of rain/snow developing and enhancing over
the Idaho Panhandle overnight with the assistance from upslope
flow. Of most concern is the 0-6z period at KMWH where cold air
remains trapped with temperatures near 32F. The passing front could
bring a brief rise in temperature to above freezing but soundings do
not indicate much mixing potential and thus put in a TEMPO group for
-FZRA. Elsewhere the lower levels are warmer over Eastern WA and
North Idaho with -RA or -RASN expected. Low level upslope flow in
combination with precipitation will moisten the low levels with
IFR/MVFR stratus expected to increase between 6-12z Tuesday. Dry
air advection behind the front will increase 12-18z Tuesday with
stratus expected to lift and become scattered by afternoon. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 33 18 28 19 28 / 60 10 0 0 0 0
Coeur d`Alene 29 35 17 31 18 29 / 70 10 0 0 0 0
Pullman 31 37 21 31 23 33 / 80 30 0 0 0 0
Lewiston 33 40 23 34 23 35 / 80 40 0 0 0 0
Colville 27 33 13 28 17 33 / 30 10 0 0 0 0
Sandpoint 30 34 16 28 17 30 / 70 10 0 0 0 0
Kellogg 29 35 20 28 18 29 / 90 30 0 0 0 0
Moses Lake 29 36 17 31 19 30 / 20 0 0 0 0 0
Wenatchee 28 35 22 29 20 32 / 10 0 0 0 0 0
Omak 27 31 14 29 16 31 / 10 10 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 AM CST SUN JAN 8 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
215 AM CST SUN JAN 8 2012
MAIN FORECAST CONCERN IS HIGH TEMPERATURES MONDAY AND TUESDAY
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO SOUTHERN
ALBERTA...AN UPPER LOW OVER ARIZONA...A SHORTWAVE TROUGH OVER
EASTERN MONTANA AND BROAD TROUGHING OVER SOUTHEAST CANADA. LACK OF
ANY SIGNIFICANT FEATURES NEAR THE FORECAST AREA RESULTING IN DRY
CONDITIONS ALONG WITH CLEAR SKIES. WITH A SURFACE HIGH PRESSURE
RIDGE IN PLACE AND A DRY ATMOSPHERE SEEN ON THE 00Z DVN AND MPX
SOUNDINGS...TEMPERATURES HAVE FALLEN INTO THE TEENS AND
20S...COLDEST IN THE TYPICAL COLD SPOTS IN WISCONSIN. UPSTREAM...
THERE IS AN AREA OF MID CLOUDS CROSSING THE DAKOTAS AHEAD OF
MONTANA SHORTWAVE TROUGH. 850MB TEMPS ACROSS THE NORTHERN
PLAINS/UPPER MIDWEST HAVE HELD FAIRLY STEADY THE PAST 12
HOURS...AROUND -4C AT BIS...ABR AND MPX FOR THEIR 12Z SOUNDINGS
YESTERDAY AND 00Z SOUNDINGS TODAY.
TODAY AND TONIGHT...SHORTWAVE TROUGH SEEN OVER EASTERN MONTANA IS
PROGGED TO DIG SOUTH INTO THE CENTRAL PLAINS...IN RESPONSE TO THE
UPPER RIDGING OVER THE WESTERN U.S. BUILDING NORTHEAST TOWARDS THE
NORTHERN PLAINS. THE AREA OF MID CLOUDS AHEAD OF THIS SHORTWAVE
THROUGH APPEAR TO SCATTER OUT/DISSIPATE AS THEY COME INTO THE
FORECAST AREA THIS AFTERNOON...LIKELY DUE TO THE SHORTWAVE DIGGING
SOUTH VERSUS EAST. THEREFORE...ANTICIPATING A MOSTLY SUNNY DAY
TODAY. WITH 925MB TEMPS EXPECTED AROUND -2C AT 18Z...HIGHS SHOULD
END UP A FEW DEGREES WARMER THAN YESTERDAY. FOR TONIGHT...MODELS
ALSO PROG A SHORTWAVE TO RIDE ON TOP OF THE BUILDING RIDGING INTO
THE NORTHERN PLAINS...FORECAST TO DROP DOWN INTO NORTHWEST WISCONSIN
AT 12Z MONDAY. THIS SHORTWAVE SHOULD HAVE A WARM FRONT ASSOCIATED
WITH IT...CROSSING THE FORECAST AREA VERY LATE TONIGHT. THIS
FRONT...IN CONJUNCTION WITH A TIGHTENING PRESSURE GRADIENT...SHOULD
HELP TO AT LEAST STABILIZE THE TEMPERATURE FALL AND POSSIBLY START
BRINGING TEMPERATURES UP AROUND 12Z. WITH CLEAR/MOSTLY CLEAR SKIES
IN THE EVENING...LOWS SHOULD FALL INTO THE 20S. NOT ANTICIPATING
MUCH MORE THAN SOME MID/HIGH CLOUD TO ACCOMPANY THE WARM FRONT...SO
NO PRECIPITATION IS FORECAST.
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING THAT WAS BUILDING
TOWARDS THE NORTHERN PLAINS TONIGHT IS PROGGED TO FLATTEN OUT AND
PUSH EAST...MOVING INTO THE FORECAST AREA FOR TUESDAY. THE FEATURE
RESPONSIBLE FOR THIS IS A POTENT SHORTWAVE TROUGH...EXPECTED TO DROP
DOWN THROUGH ALBERTA ON TUESDAY...THEN DIG INTO EASTERN MONTANA AND
THE WESTERN DAKOTAS BY 12Z WEDNESDAY. FOR OUR AREA...THE MAIN
CONCERN IS TEMPERATURES...WITH THE UPPER RIDGING BRINGING WITH IT A
SURGE OF PACIFIC AIR MODIFIED BY DOWNSLOPING OFF THE ROCKIES. 925MB
TEMPS CLIMB TO 0-2C FOR 18Z MONDAY AND 2-6C FOR 18Z TUESDAY. COOLEST
READINGS ARE NORTH OF I-94. THIS CLIMB IN TEMPERATURES IS
ACCOMPANIED BY WHAT SHOULD BE BREEZY WEST TO SOUTHWEST WINDS...NOTED
BY 925MB WINDS STAYING UP BETWEEN 20-35KT FOR THE ENTIRE TIME
PERIOD. AMOUNT OF SUNSHINE WILL BE CRITICAL IN DETERMINING HOW WARM
WE GET...GIVEN THE LACK OF SNOW COVER. LOOKS TO BE SOME MID/HIGH
CLOUDS AROUND MONDAY MORNING...BUT THESE SHOULD SCATTER/CLEAR OUT IN
THE AFTERNOON AS THE UPPER RIDGE FLATTENS. ANOTHER WAVE OF MID/HIGH
CLOUDS LOOKS TO COME THROUGH MONDAY NIGHT INTO TUESDAY MORNING...BUT
AGAIN CLEARING OUT FOR THE AFTERNOON. THEREFORE...PLENTY OF
SUN IS ANTICIPATED...ESPECIALLY TUESDAY FOR WARMING. PREVIOUS
FORECAST HIGHS FOR BOTH MONDAY AND TUESDAY LOOK VERY
REASONABLE...STAYING ON THE HIGH END OF GUIDANCE WHICH HAS WORKED
FOR THE RECENT ABOVE NORMAL STRETCH. POTENTIAL DEFINITELY EXISTS
TO BREAK SOME RECORD HIGHS. LOWS MONDAY NIGHT LIKELY TO STAY WELL
ABOVE NORMAL TOO...ESPECIALLY OVER HIGHER TERRAIN AREAS. FOR
TUESDAY NIGHT...A COLD FRONT WELL AHEAD OF THE POTENT UPPER TROUGH
LOOKS TO MOVE THROUGH THE AREA BETWEEN 06-12Z. SKIES SHOULD STAY
MOSTLY CLEAR...BUT COLD ADVECTION REALLY DOESNT GET GOING UNTIL
AFTER 12Z. THEREFORE HAVE STAYED ON THE WARM SIDE OF
GUIDANCE...ESPECIALLY GIVEN THE WARM TUESDAY.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
215 AM CST SUN JAN 8 2012
MAIN FORECAST CONCERN AND UNCERTAINTY FOR THE LONG TERM FORECAST
CONTINUES TO REVOLVE AROUND THAT POTENT TROUGH APPROACHING THE
NORTHERN PLAINS 12Z WEDNESDAY. 08.00Z ECMWF/GFS/CANADIAN ALL SHOW
THE TROUGH DIGGING INTO THE NORTHERN PLAINS ON WEDNESDAY THEN
PUSHING EAST...BUT THE EXTENT OF THE DIGGING AND THE TIMING OF HOW
FAST IT MOVES EAST ARE BOTH IN QUESTION. THE ECMWF AND TO SOME
DEGREE THE CANADIAN ARE BY FAR THE DEEPEST...AND BOTH PRODUCE A
TROWAL AREA OF PRECIPITATION THAT CROSSES THE FORECAST AREA MOSTLY
WEDNESDAY NIGHT. THE GFS...BEING LESS AMPLIFIED AND MORE
PROGRESSIVE...KEEPS ANY TROWAL AREA OF PRECIPITATION NORTH OF THE
AREA. ALL SOLUTIONS AGREE ON PRETTY DRAMATIC COOLING...WITH 850MB
TEMPS DROPPING FROM 4-6C AT 12Z WEDNESDAY TO -12 TO -16C BY 12Z
THURSDAY AND POTENTIALLY NEAR -20C BY 00Z FRIDAY. FOR NOW...TO
HANDLE THE UNCERTAINTIES FOR WEDNESDAY THROUGH THURSDAY...HAVE
STAYED WITH THE CONSENSUS APPROACH FOR BOTH PRECIPITATION CHANCES
AND TEMPERATURES. ONE DISTINCT CHANGE IS THAT WEDNESDAY ENDS UP
WARMER...DUE TO THE COOLING WHICH HAS TRENDED SLOWER. WOULD NOT BE
SURPRISED IF WEDNESDAY MAY HAVE TO BE WARMED EVEN MORE.
THE PERIOD FOR THURSDAY NIGHT THROUGH SATURDAY NIGHT DOES NOT GET
ANY EASIER TO FORECAST...AGAIN RELATED TO HOW FAST THE POTENT TROUGH
CAN EXIT TO THE NORTHEAST. ONE THING FOR CERTAIN IS THAT THERE IS A
STRONG CONSENSUS FOR RIDGING TO BUILD OVER THE WESTERN U.S. INTO
SOUTHWEST CANADA DURING THIS TIME. HOW MUCH OF THIS SPREADS EAST
INTO THE FORECAST AREA IS UNKNOWN. THE 08.00Z GFS TRIES TO SPREAD
SOME RIDGING INTO THE FORECAST AREA LATE SATURDAY...BUT THE ECMWF
AND GFS ENSEMBLES WOULD PREFER TROUGHING TO STAY LOCKED IN PLACE.
THINK THE LATTER SCENARIO IS MORE LIKELY. THIS MEANS ONLY A SLOW
MODERATION IN TEMPERATURES. POTENTIAL WOULD EXIST FOR SOME
PRECIPITATION CHANCES WITH SHORTWAVES RIDING THROUGH THE NORTHWEST
FLOW ALOFT...AS INDICATED BY THE NEW 08.00Z ECMWF FOR SATURDAY.
HOWEVER...TIMING SOMETHING THAT FAR OUT IN THE FORECAST AND GIVEN
THE UNCERTAINTIES IN THE UPPER PATTERN...HAVE LEFT THE THURSDAY
NIGHT THROUGH SATURDAY NIGHT TIME PERIOD DRY.
&&
.AVIATION...THROUGH 18Z MONDAY
1136 AM CST SUN JAN 8 2012
A TROUGH WILL MOVE THROUGH THE REGION LATE TONIGHT AND EARLY
MONDAY MORNING. A BROKEN DECK OF HIGH CLOUDS WILL MOVE INTO THE
REGION AFTER 09.02Z. THIS CLOUD DECK WILL THEN GRADUALLY LOWER TO
AROUND 5K FEET TOWARD SUNRISE. BETWEEN 09.13Z AND 09.16Z...THESE
CLOUDS WILL MOVE QUICKLY OUT OF THE AREA. IN THE WAKE OF THIS
TROUGH THE WINDS WILL QUICKLY SHIFT FROM SOUTH TO WEST AND
INCREASE INTO THE 15 TO 25 KNOT RANGE. IN ADDITION...THE WINDS
WILL START TO GUST TO AROUND 30 KNOTS IN NORTHEAST IOWA AND
SOUTHEAST MINNESOTA AROUND 09.17Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 AM CST SUN JAN 8 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
516 AM CST SUN JAN 8 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
215 AM CST SUN JAN 8 2012
MAIN FORECAST CONCERN IS HIGH TEMPERATURES MONDAY AND TUESDAY
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO SOUTHERN
ALBERTA...AN UPPER LOW OVER ARIZONA...A SHORTWAVE TROUGH OVER
EASTERN MONTANA AND BROAD TROUGHING OVER SOUTHEAST CANADA. LACK OF
ANY SIGNIFICANT FEATURES NEAR THE FORECAST AREA RESULTING IN DRY
CONDITIONS ALONG WITH CLEAR SKIES. WITH A SURFACE HIGH PRESSURE
RIDGE IN PLACE AND A DRY ATMOSPHERE SEEN ON THE 00Z DVN AND MPX
SOUNDINGS...TEMPERATURES HAVE FALLEN INTO THE TEENS AND
20S...COLDEST IN THE TYPICAL COLD SPOTS IN WISCONSIN. UPSTREAM...
THERE IS AN AREA OF MID CLOUDS CROSSING THE DAKOTAS AHEAD OF
MONTANA SHORTWAVE TROUGH. 850MB TEMPS ACROSS THE NORTHERN
PLAINS/UPPER MIDWEST HAVE HELD FAIRLY STEADY THE PAST 12
HOURS...AROUND -4C AT BIS...ABR AND MPX FOR THEIR 12Z SOUNDINGS
YESTERDAY AND 00Z SOUNDINGS TODAY.
TODAY AND TONIGHT...SHORTWAVE TROUGH SEEN OVER EASTERN MONTANA IS
PROGGED TO DIG SOUTH INTO THE CENTRAL PLAINS...IN RESPONSE TO THE
UPPER RIDGING OVER THE WESTERN U.S. BUILDING NORTHEAST TOWARDS THE
NORTHERN PLAINS. THE AREA OF MID CLOUDS AHEAD OF THIS SHORTWAVE
THROUGH APPEAR TO SCATTER OUT/DISSIPATE AS THEY COME INTO THE
FORECAST AREA THIS AFTERNOON...LIKELY DUE TO THE SHORTWAVE DIGGING
SOUTH VERSUS EAST. THEREFORE...ANTICIPATING A MOSTLY SUNNY DAY
TODAY. WITH 925MB TEMPS EXPECTED AROUND -2C AT 18Z...HIGHS SHOULD
END UP A FEW DEGREES WARMER THAN YESTERDAY. FOR TONIGHT...MODELS
ALSO PROG A SHORTWAVE TO RIDE ON TOP OF THE BUILDING RIDGING INTO
THE NORTHERN PLAINS...FORECAST TO DROP DOWN INTO NORTHWEST WISCONSIN
AT 12Z MONDAY. THIS SHORTWAVE SHOULD HAVE A WARM FRONT ASSOCIATED
WITH IT...CROSSING THE FORECAST AREA VERY LATE TONIGHT. THIS
FRONT...IN CONJUNCTION WITH A TIGHTENING PRESSURE GRADIENT...SHOULD
HELP TO AT LEAST STABILIZE THE TEMPERATURE FALL AND POSSIBLY START
BRINGING TEMPERATURES UP AROUND 12Z. WITH CLEAR/MOSTLY CLEAR SKIES
IN THE EVENING...LOWS SHOULD FALL INTO THE 20S. NOT ANTICIPATING
MUCH MORE THAN SOME MID/HIGH CLOUD TO ACCOMPANY THE WARM FRONT...SO
NO PRECIPITATION IS FORECAST.
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING THAT WAS BUILDING
TOWARDS THE NORTHERN PLAINS TONIGHT IS PROGGED TO FLATTEN OUT AND
PUSH EAST...MOVING INTO THE FORECAST AREA FOR TUESDAY. THE FEATURE
RESPONSIBLE FOR THIS IS A POTENT SHORTWAVE TROUGH...EXPECTED TO DROP
DOWN THROUGH ALBERTA ON TUESDAY...THEN DIG INTO EASTERN MONTANA AND
THE WESTERN DAKOTAS BY 12Z WEDNESDAY. FOR OUR AREA...THE MAIN
CONCERN IS TEMPERATURES...WITH THE UPPER RIDGING BRINGING WITH IT A
SURGE OF PACIFIC AIR MODIFIED BY DOWNSLOPING OFF THE ROCKIES. 925MB
TEMPS CLIMB TO 0-2C FOR 18Z MONDAY AND 2-6C FOR 18Z TUESDAY. COOLEST
READINGS ARE NORTH OF I-94. THIS CLIMB IN TEMPERATURES IS
ACCOMPANIED BY WHAT SHOULD BE BREEZY WEST TO SOUTHWEST WINDS...NOTED
BY 925MB WINDS STAYING UP BETWEEN 20-35KT FOR THE ENTIRE TIME
PERIOD. AMOUNT OF SUNSHINE WILL BE CRITICAL IN DETERMINING HOW WARM
WE GET...GIVEN THE LACK OF SNOW COVER. LOOKS TO BE SOME MID/HIGH
CLOUDS AROUND MONDAY MORNING...BUT THESE SHOULD SCATTER/CLEAR OUT IN
THE AFTERNOON AS THE UPPER RIDGE FLATTENS. ANOTHER WAVE OF MID/HIGH
CLOUDS LOOKS TO COME THROUGH MONDAY NIGHT INTO TUESDAY MORNING...BUT
AGAIN CLEARING OUT FOR THE AFTERNOON. THEREFORE...PLENTY OF
SUN IS ANTICIPATED...ESPECIALLY TUESDAY FOR WARMING. PREVIOUS
FORECAST HIGHS FOR BOTH MONDAY AND TUESDAY LOOK VERY
REASONABLE...STAYING ON THE HIGH END OF GUIDANCE WHICH HAS WORKED
FOR THE RECENT ABOVE NORMAL STRETCH. POTENTIAL DEFINITELY EXISTS
TO BREAK SOME RECORD HIGHS. LOWS MONDAY NIGHT LIKELY TO STAY WELL
ABOVE NORMAL TOO...ESPECIALLY OVER HIGHER TERRAIN AREAS. FOR
TUESDAY NIGHT...A COLD FRONT WELL AHEAD OF THE POTENT UPPER TROUGH
LOOKS TO MOVE THROUGH THE AREA BETWEEN 06-12Z. SKIES SHOULD STAY
MOSTLY CLEAR...BUT COLD ADVECTION REALLY DOESNT GET GOING UNTIL
AFTER 12Z. THEREFORE HAVE STAYED ON THE WARM SIDE OF
GUIDANCE...ESPECIALLY GIVEN THE WARM TUESDAY.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
215 AM CST SUN JAN 8 2012
MAIN FORECAST CONCERN AND UNCERTAINTY FOR THE LONG TERM FORECAST
CONTINUES TO REVOLVE AROUND THAT POTENT TROUGH APPROACHING THE
NORTHERN PLAINS 12Z WEDNESDAY. 08.00Z ECMWF/GFS/CANADIAN ALL SHOW
THE TROUGH DIGGING INTO THE NORTHERN PLAINS ON WEDNESDAY THEN
PUSHING EAST...BUT THE EXTENT OF THE DIGGING AND THE TIMING OF HOW
FAST IT MOVES EAST ARE BOTH IN QUESTION. THE ECMWF AND TO SOME
DEGREE THE CANADIAN ARE BY FAR THE DEEPEST...AND BOTH PRODUCE A
TROWAL AREA OF PRECIPITATION THAT CROSSES THE FORECAST AREA MOSTLY
WEDNESDAY NIGHT. THE GFS...BEING LESS AMPLIFIED AND MORE
PROGRESSIVE...KEEPS ANY TROWAL AREA OF PRECIPITATION NORTH OF THE
AREA. ALL SOLUTIONS AGREE ON PRETTY DRAMATIC COOLING...WITH 850MB
TEMPS DROPPING FROM 4-6C AT 12Z WEDNESDAY TO -12 TO -16C BY 12Z
THURSDAY AND POTENTIALLY NEAR -20C BY 00Z FRIDAY. FOR NOW...TO
HANDLE THE UNCERTAINTIES FOR WEDNESDAY THROUGH THURSDAY...HAVE
STAYED WITH THE CONSENSUS APPROACH FOR BOTH PRECIPITATION CHANCES
AND TEMPERATURES. ONE DISTINCT CHANGE IS THAT WEDNESDAY ENDS UP
WARMER...DUE TO THE COOLING WHICH HAS TRENDED SLOWER. WOULD NOT BE
SURPRISED IF WEDNESDAY MAY HAVE TO BE WARMED EVEN MORE.
THE PERIOD FOR THURSDAY NIGHT THROUGH SATURDAY NIGHT DOES NOT GET
ANY EASIER TO FORECAST...AGAIN RELATED TO HOW FAST THE POTENT TROUGH
CAN EXIT TO THE NORTHEAST. ONE THING FOR CERTAIN IS THAT THERE IS A
STRONG CONSENSUS FOR RIDGING TO BUILD OVER THE WESTERN U.S. INTO
SOUTHWEST CANADA DURING THIS TIME. HOW MUCH OF THIS SPREADS EAST
INTO THE FORECAST AREA IS UNKNOWN. THE 08.00Z GFS TRIES TO SPREAD
SOME RIDGING INTO THE FORECAST AREA LATE SATURDAY...BUT THE ECMWF
AND GFS ENSEMBLES WOULD PREFER TROUGHING TO STAY LOCKED IN PLACE.
THINK THE LATTER SCENARIO IS MORE LIKELY. THIS MEANS ONLY A SLOW
MODERATION IN TEMPERATURES. POTENTIAL WOULD EXIST FOR SOME
PRECIPITATION CHANCES WITH SHORTWAVES RIDING THROUGH THE NORTHWEST
FLOW ALOFT...AS INDICATED BY THE NEW 08.00Z ECMWF FOR SATURDAY.
HOWEVER...TIMING SOMETHING THAT FAR OUT IN THE FORECAST AND GIVEN
THE UNCERTAINTIES IN THE UPPER PATTERN...HAVE LEFT THE THURSDAY
NIGHT THROUGH SATURDAY NIGHT TIME PERIOD DRY.
&&
.AVIATION...TODAY AND TONIGHT
516 AM CST SUN JAN 8 2012
VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE FORECAST
PERIOD. A WEAK UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION TODAY
BRINGING A FEW MID LEVEL CLOUDS TO THE TAF SITES...WITH CLOUD
BASES IN THE 8 TO 12 KFT RANGE. PLAN ON SOUTHWEST WINDS AT 5 TO 8
KTS TODAY. WINDS WILL GRADUALLY INCREASE TONIGHT AS A TROUGH MOVES
FROM THE NORTHERN PLAINS INTO THE GREAT LAKES. LOOK FOR SOUTHWEST
WINDS TO INCREASE INTO THE 10 TO 15 KT RANGE...MAINLY AFTER 06Z.
THE TROUGH WILL BRING A SCATTERED TO BROKEN CLOUD DECK ACROSS THE
TAF SITES WITH CLOUD BASES IN THE 8 TO 12 KFT RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 AM CST SUN JAN 8 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
215 AM CST SUN JAN 8 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
215 AM CST SUN JAN 8 2012
MAIN FORECAST CONCERN IS HIGH TEMPERATURES MONDAY AND TUESDAY
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO SOUTHERN
ALBERTA...AN UPPER LOW OVER ARIZONA...A SHORTWAVE TROUGH OVER
EASTERN MONTANA AND BROAD TROUGHING OVER SOUTHEAST CANADA. LACK OF
ANY SIGNIFICANT FEATURES NEAR THE FORECAST AREA RESULTING IN DRY
CONDITIONS ALONG WITH CLEAR SKIES. WITH A SURFACE HIGH PRESSURE
RIDGE IN PLACE AND A DRY ATMOSPHERE SEEN ON THE 00Z DVN AND MPX
SOUNDINGS...TEMPERATURES HAVE FALLEN INTO THE TEENS AND
20S...COLDEST IN THE TYPICAL COLD SPOTS IN WISCONSIN. UPSTREAM...
THERE IS AN AREA OF MID CLOUDS CROSSING THE DAKOTAS AHEAD OF
MONTANA SHORTWAVE TROUGH. 850MB TEMPS ACROSS THE NORTHERN
PLAINS/UPPER MIDWEST HAVE HELD FAIRLY STEADY THE PAST 12
HOURS...AROUND -4C AT BIS...ABR AND MPX FOR THEIR 12Z SOUNDINGS
YESTERDAY AND 00Z SOUNDINGS TODAY.
TODAY AND TONIGHT...SHORTWAVE TROUGH SEEN OVER EASTERN MONTANA IS
PROGGED TO DIG SOUTH INTO THE CENTRAL PLAINS...IN RESPONSE TO THE
UPPER RIDGING OVER THE WESTERN U.S. BUILDING NORTHEAST TOWARDS THE
NORTHERN PLAINS. THE AREA OF MID CLOUDS AHEAD OF THIS SHORTWAVE
THROUGH APPEAR TO SCATTER OUT/DISSIPATE AS THEY COME INTO THE
FORECAST AREA THIS AFTERNOON...LIKELY DUE TO THE SHORTWAVE DIGGING
SOUTH VERSUS EAST. THEREFORE...ANTICIPATING A MOSTLY SUNNY DAY
TODAY. WITH 925MB TEMPS EXPECTED AROUND -2C AT 18Z...HIGHS SHOULD
END UP A FEW DEGREES WARMER THAN YESTERDAY. FOR TONIGHT...MODELS
ALSO PROG A SHORTWAVE TO RIDE ON TOP OF THE BUILDING RIDGING INTO
THE NORTHERN PLAINS...FORECAST TO DROP DOWN INTO NORTHWEST WISCONSIN
AT 12Z MONDAY. THIS SHORTWAVE SHOULD HAVE A WARM FRONT ASSOCIATED
WITH IT...CROSSING THE FORECAST AREA VERY LATE TONIGHT. THIS
FRONT...IN CONJUNCTION WITH A TIGHTENING PRESSURE GRADIENT...SHOULD
HELP TO AT LEAST STABILIZE THE TEMPERATURE FALL AND POSSIBLY START
BRINGING TEMPERATURES UP AROUND 12Z. WITH CLEAR/MOSTLY CLEAR SKIES
IN THE EVENING...LOWS SHOULD FALL INTO THE 20S. NOT ANTICIPATING
MUCH MORE THAN SOME MID/HIGH CLOUD TO ACCOMPANY THE WARM FRONT...SO
NO PRECIPITATION IS FORECAST.
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING THAT WAS BUILDING
TOWARDS THE NORTHERN PLAINS TONIGHT IS PROGGED TO FLATTEN OUT AND
PUSH EAST...MOVING INTO THE FORECAST AREA FOR TUESDAY. THE FEATURE
RESPONSIBLE FOR THIS IS A POTENT SHORTWAVE TROUGH...EXPECTED TO DROP
DOWN THROUGH ALBERTA ON TUESDAY...THEN DIG INTO EASTERN MONTANA AND
THE WESTERN DAKOTAS BY 12Z WEDNESDAY. FOR OUR AREA...THE MAIN
CONCERN IS TEMPERATURES...WITH THE UPPER RIDGING BRINGING WITH IT A
SURGE OF PACIFIC AIR MODIFIED BY DOWNSLOPING OFF THE ROCKIES. 925MB
TEMPS CLIMB TO 0-2C FOR 18Z MONDAY AND 2-6C FOR 18Z TUESDAY. COOLEST
READINGS ARE NORTH OF I-94. THIS CLIMB IN TEMPERATURES IS
ACCOMPANIED BY WHAT SHOULD BE BREEZY WEST TO SOUTHWEST WINDS...NOTED
BY 925MB WINDS STAYING UP BETWEEN 20-35KT FOR THE ENTIRE TIME
PERIOD. AMOUNT OF SUNSHINE WILL BE CRITICAL IN DETERMINING HOW WARM
WE GET...GIVEN THE LACK OF SNOW COVER. LOOKS TO BE SOME MID/HIGH
CLOUDS AROUND MONDAY MORNING...BUT THESE SHOULD SCATTER/CLEAR OUT IN
THE AFTERNOON AS THE UPPER RIDGE FLATTENS. ANOTHER WAVE OF MID/HIGH
CLOUDS LOOKS TO COME THROUGH MONDAY NIGHT INTO TUESDAY MORNING...BUT
AGAIN CLEARING OUT FOR THE AFTERNOON. THEREFORE...PLENTY OF
SUN IS ANTICIPATED...ESPECIALLY TUESDAY FOR WARMING. PREVIOUS
FORECAST HIGHS FOR BOTH MONDAY AND TUESDAY LOOK VERY
REASONABLE...STAYING ON THE HIGH END OF GUIDANCE WHICH HAS WORKED
FOR THE RECENT ABOVE NORMAL STRETCH. POTENTIAL DEFINITELY EXISTS
TO BREAK SOME RECORD HIGHS. LOWS MONDAY NIGHT LIKELY TO STAY WELL
ABOVE NORMAL TOO...ESPECIALLY OVER HIGHER TERRAIN AREAS. FOR
TUESDAY NIGHT...A COLD FRONT WELL AHEAD OF THE POTENT UPPER TROUGH
LOOKS TO MOVE THROUGH THE AREA BETWEEN 06-12Z. SKIES SHOULD STAY
MOSTLY CLEAR...BUT COLD ADVECTION REALLY DOESNT GET GOING UNTIL
AFTER 12Z. THEREFORE HAVE STAYED ON THE WARM SIDE OF
GUIDANCE...ESPECIALLY GIVEN THE WARM TUESDAY.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
215 AM CST SUN JAN 8 2012
MAIN FORECAST CONCERN AND UNCERTAINTY FOR THE LONG TERM FORECAST
CONTINUES TO REVOLVE AROUND THAT POTENT TROUGH APPROACHING THE
NORTHERN PLAINS 12Z WEDNESDAY. 08.00Z ECMWF/GFS/CANADIAN ALL SHOW
THE TROUGH DIGGING INTO THE NORTHERN PLAINS ON WEDNESDAY THEN
PUSHING EAST...BUT THE EXTENT OF THE DIGGING AND THE TIMING OF HOW
FAST IT MOVES EAST ARE BOTH IN QUESTION. THE ECMWF AND TO SOME
DEGREE THE CANADIAN ARE BY FAR THE DEEPEST...AND BOTH PRODUCE A
TROWAL AREA OF PRECIPITATION THAT CROSSES THE FORECAST AREA MOSTLY
WEDNESDAY NIGHT. THE GFS...BEING LESS AMPLIFIED AND MORE
PROGRESSIVE...KEEPS ANY TROWAL AREA OF PRECIPITATION NORTH OF THE
AREA. ALL SOLUTIONS AGREE ON PRETTY DRAMATIC COOLING...WITH 850MB
TEMPS DROPPING FROM 4-6C AT 12Z WEDNESDAY TO -12 TO -16C BY 12Z
THURSDAY AND POTENTIALLY NEAR -20C BY 00Z FRIDAY. FOR NOW...TO
HANDLE THE UNCERTAINTIES FOR WEDNESDAY THROUGH THURSDAY...HAVE
STAYED WITH THE CONSENSUS APPROACH FOR BOTH PRECIPITATION CHANCES
AND TEMPERATURES. ONE DISTINCT CHANGE IS THAT WEDNESDAY ENDS UP
WARMER...DUE TO THE COOLING WHICH HAS TRENDED SLOWER. WOULD NOT BE
SURPRISED IF WEDNESDAY MAY HAVE TO BE WARMED EVEN MORE.
THE PERIOD FOR THURSDAY NIGHT THROUGH SATURDAY NIGHT DOES NOT GET
ANY EASIER TO FORECAST...AGAIN RELATED TO HOW FAST THE POTENT TROUGH
CAN EXIT TO THE NORTHEAST. ONE THING FOR CERTAIN IS THAT THERE IS A
STRONG CONSENSUS FOR RIDGING TO BUILD OVER THE WESTERN U.S. INTO
SOUTHWEST CANADA DURING THIS TIME. HOW MUCH OF THIS SPREADS EAST
INTO THE FORECAST AREA IS UNKNOWN. THE 08.00Z GFS TRIES TO SPREAD
SOME RIDGING INTO THE FORECAST AREA LATE SATURDAY...BUT THE ECMWF
AND GFS ENSEMBLES WOULD PREFER TROUGHING TO STAY LOCKED IN PLACE.
THINK THE LATTER SCENARIO IS MORE LIKELY. THIS MEANS ONLY A SLOW
MODERATION IN TEMPERATURES. POTENTIAL WOULD EXIST FOR SOME
PRECIPITATION CHANCES WITH SHORTWAVES RIDING THROUGH THE NORTHWEST
FLOW ALOFT...AS INDICATED BY THE NEW 08.00Z ECMWF FOR SATURDAY.
HOWEVER...TIMING SOMETHING THAT FAR OUT IN THE FORECAST AND GIVEN
THE UNCERTAINTIES IN THE UPPER PATTERN...HAVE LEFT THE THURSDAY
NIGHT THROUGH SATURDAY NIGHT TIME PERIOD DRY.
&&
.AVIATION...
1100 PM CST SAT JAN 7 2012
A WEAK SFC HIGH WILL MOVE EAST ACROSS THE REGION ON SUNDAY. LOOK FOR
A MOSTLY LIGHT WIND FIELD FROM THE SOUTHWEST. SOME HIGH THIN CLOUDS
COULD SPILL ACROSS THE TAF SITES...ASSOCIATED WITH UPPER LEVEL
DISTURBANCES MOVING WEST-EAST ACROSS IA/IL AND THE NORTHERN
PLAINS...BUT VFR CONDITIONS ARE EXPECTED.
THE SFC PRESSURE GRADIENT WILL START TO TIGHTEN SUNDAY NIGHT...
PERSISTING THROUGH MONDAY. LOOK FOR INCREASING WINDS IN THIS PERIOD
AS A RESULT...STAYING FROM THE SOUTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 AM CST SUN JAN 8 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1242 AM EST TUE JAN 10 2012
.SYNOPSIS...
LOW PRESSURE PASSES WELL OFFSHORE TONIGHT. HIGH PRESSURE BUILDS IN
TUESDAY AND WEDNESDAY. LOW PRESSURE APPROACHES ON WEDNESDAY NIGHT
AND PASSES THROUGH ON THURSDAY. A BROAD AREA OF LOW PRESSURE
REMAINS ACROSS THE AREA THROUGH FRIDAY NIGHT. HIGH PRESSURE THEN
BUILDS IN DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MINOR ADJUSTMENTS TO TEMPS AND DEWPOINTS. LOWS TEMPERATURES HAVE
ALREADY BEEN REACHED IN THE RURAL OUTLYING SECTIONS WITH OTHER
LOCATIONS DROPPING AT LEAST ANOTHER SEVERAL DEGREES BY THE EARLY
MORNING HOURS. POPS TAPERED DOWN SLIGHTLY AND PUSHED FARTHER SOUTH
AND EAST BUT DID NOT WANT TO DROP THEM ALL TOGETHER GIVEN THE
POTENT SHORTWAVE STILL FORECAST TO MOVE JUST SOUTH OF THE AREA.
LEFT POPS AT SLIGHT CHANCE. LOCAL WRF AND HRRR ALSO SHOW SOME
FORECAST PRECIP WITHIN SOUTHEAST PORTIONS OF FORECAST
AREA...MAINLY SOUTH OF LONG ISLAND THOUGH. HOWEVER...IF THE TREND
CONTINUES WITH THE RADAR RETURNS...LOOKS LIKE MUCH OF THE FORECAST
REGION WILL REMAIN DRY TONIGHT WITH ANY PRECIPITATION STAYING
SOUTH OF LONG ISLAND AFFECTING SOUTHERN OUTER PORTIONS OF OCEAN
MARINE ZONES.
PRECIP TYPE AFTER ACCOUNTING FOR WET BULB PROFILES WILL ALLOW FOR
ANY PRECIPITATION TO BE MOSTLY LIGHT SNOW FOR CENTRAL LONG ISLAND
AND SOUTHEAST CONNECTICUT AND A MIX OF RAIN AND SNOW CLOSER TO THE
TWIN FORKS OF LONG ISLAND. THE TIME PERIOD OF THIS WOULD BE MAINLY
AFTER MIDNIGHT AND COULD BE BRIEF IN DURATION AS TOTAL QPF IS AT
BEST A FEW HUNDREDTHS OF AN INCH OR LESS. THE 12Z CMC AND 12Z NAM
MODELS SHOW A THE QPF FIELD BRUSHING A RELATIVELY GREATER FRACTION
OF THE TWIN FORKS OF LONG ISLAND AND SOUTHEAST CONNECTICUT. NO
ACCUMULATION OF SNOW EXPECTED.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
RIDGING AT THE SURFACE AND ALOFT FOR THE PERIOD. OUTSIDE OF SOME
AFTERNOON CUMULUS MAINLY ACROSS THE INTERIOR ZONES...PRIMARILY A
CLEAR SKY. GUIDANCE IN GOOD AGREEMENT WITH A CONTINUATION OF ABOVE
NORMAL TEMPERATURES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
12Z NAM CLEAR OUTLIER IN HOW IT IS HANDLING SYSTEM THAT WILL IMPACT
REGION WEDNESDAY NIGHT/THURSDAY SO WAS NOT USED FROM WEDNESDAY ON.
INSTEAD WITH BLEND OF MORE CONSISTENT ECMWF/SREF/CMC/GFS...THOUGH
DID LEAN TOWARD SLOWER TIMING IN ECMWF/SREF WITH THIS SYSTEM.
THE REGION SHOULD BE DRY WEDNESDAY WITH A DEEP LAYERED RIDGE
BUILDING IN...ASSOCIATED SUBSIDENCE SHOULD LIMIT MIXING TO AROUND
925 HPA...AND HELP SLOW BUILD IN OF OVER RUNNING CLOUDS AHEAD OF THE
SYSTEM AS IT MOVES INTO THE SOUTHERN APPALACHIANS.
USED A BLEND OF MAV/MET GUIDANCE FOR HIGHS...TWEAKED SLIGHTLY TOWARD
WARMER NUMBERS DUE TO EXPECT MORE SUN THAN CLOUDS - EVEN IF FILTERED
AT TIMES. FORECASTING HIGHS AROUND 5 DEGREES ABOVE NORMAL AS A
RESULT.
OVER RUNNING STRENGTHENS FROM THE LOWER TO THE MID LEVELS WEDNESDAY
NIGHT...AS RIDGE AXIS SLOWLY LIFTS TO OUR NE. BECAUSE OF THE
RELATIVELY SLOW TIMING FOR THE RIDGE AXIS LIFTING TO THE NE...AM
SOMEWHAT CONCERNED THAT THE FORECAST COULD BE TOO AGGRESSIVE IN
BRINGING IN PRECIPITATION...ESPECIALLY BEFORE MIDNIGHT.
WITH THE COLUMN BEING FAIRLY SLOW TO MOISTEN...ESPECIALLY EASTERN
ZONES COULD SEE SOME RADIATIONAL COOLING IN THE EVENING...SO HAVE
COLDEST LOWS FORECAST OVER INTERIOR SE CT AS A RESULT WEDNESDAY
NIGHT. WOULD EXPECT TEMPERATURES TO LEVEL OFF AFTER MIDNIGHT...AND
POSSIBLY BEGIN TO RISE LATE IN THE NYC METRO. WENT WITH A MAV/MET
BLEND...WEIGHED TOWARDS COOLER NUMBERS AT A GIVEN LOCATION. THIS
STILL YIELDS VALUES 10-15 DEGREES ABOVE NORMAL.
LOW LEVEL THERMAL PROFILES IN THE GFS/ECMWF/CMC/SREF SUGGEST
NORTHERN ZONES LIKELY WILL START AS A PERIOD OF LIGHT SNOW OR A
SNOW/RAIN MIX DEPENDING ON EXACTLY HOW TEMPERATURES PLAY OUT IN THE
LOWER BOUNDARY LEVEL. AT THIS TIME THOUGH...WOULD EXPECT LITTLE OR
NO ACCUMULATION...EXCEPT FOR POSSIBLY IN ELEVATIONS ABOVE 1000 FT OR
SO.
PRECIPITATION CHANGES TO ALL RAIN THROUGHOUT DURING THURSDAY
MORNING. THE RAIN COULD BE LOCALLY HEAVY AT TIMES LATE WEDNESDAY
NIGHT/THURSDAY MORNING. SEE HYDROLOGY SECTION FOR MORE DETAILS. THE
RAIN SHOULD TAPER OFF TO SHOWERS THURSDAY AFTERNOON.
WITH SOMETHING AROUND A 995 HPA LOW FORECAST TO TRACK TO OUR S...AND
A RELATIVELY STRONG EASTERLY LOW LEVEL JET FORECAST AHEAD OF
IT...HAVE THE POTENTIAL FOR STRONG GUSTY WINDS FROM LATE WEDNESDAY
NIGHT INTO THURSDAY...FOR NOW GOING JUST BELOW ADVISORY LEVELS AS
THERE IS SOME QUESTION AS TO HOW WELL MIXED THE MARINE BOUNDARY
LAYER WILL BE...BUT IF THE GFS IS CORRECT...COULD ULTIMATELY END UP
NEEDING A WIND ADVISORY OVER LONG ISLAND/COASTAL CT/NYC ZONES.
PREFERRED BLEND IS FAIRLY CONSISTENT IN SHOWING SOME DEFORMATION
AXIS SHOWERS THURSDAY NIGHT. DIFFERENCE DO ARISE BETWEEN THE GFS AND
THE ECMWF/CMC IN THE HANDLING OF THE CUTOFF LOW THAT MOVES ACROSS
THE GREAT LAKES REGION THURSDAY NIGHT. THE GFS IS THE FASTEST TO
EJECT THE SHORTWAVE THAT DRIVES THE COASTAL LOW...AND HAVE THE
CUTOFF LOW TO THE WEST DOMINATE...WHILE THE OTHERS MOVE THE
SHORTWAVE THAT IS SUPPORTING THE COASTAL LOW ALONG SLOWER...AND
KEEPING THE INFLUENCE OF THE CUTOFF LOW SEPARATE. WENT WITH
ECMWF/CMC HANDLING OF THESE FEATURES...DUE TO CONTINUITY ISSUES
LATER IN THE FORECAST. AS A RESULT...EXPECT MORE LOW LEVEL COLD AIR
TO BUILD IN BEHIND THE COASTAL LOW THAN DEPICTED IN THE GFS...AND AS
A RESULT HAVE SHRA/SHSN MIX ACROSS INTERIOR ZONES THURSDAY
NIGHT...WITH RAIN SHOWERS ELSEWHERE.
FROM FRIDAY ON...THE GFS CONTINUES TO DEPART FROM THE ECMWF/CMC AND
ITS OWN ENSEMBLE MEAN...SO WAS NOT FOLLOWED IN MAKING THE REMAINDER
OF THE FORECAST. RELIED MAINLY ON A ECMWF/CMC BLEND...WITH SOME
WEIGHING IN OF THE GFS ENSEMBLE MEAN FROM FRIDAY-MONDAY.
COULD SEE SOME LINGERING SHSN INTERIOR/SHRA/SHSN REMAINDER FRIDAY
MORNING...ESPECIALLY OVER EASTERN ZONES...THEN SOME INSTABILITY
SHOWERS OVER NW ZONES FRIDAY AFTERNOON...IN RESPONSE TO SHORTWAVE
ROTATING AROUND BASE OF CUTOFF LOW. FOR NOW WENT DRY FRIDAY
NIGHT-SATURDAY NIGHT IN NW FLOW ALOFT...THOUGH CANNOT COMPLETELY
RULE OUT ISOLATED SHRA/SHSN WITH ANY EMBEDDED SHORTWAVES PASSING BY.
HAVE SLIGHT CHANCE POPS SUNDAY FOR SHSN WITH PASSAGE OF 500 HPA
TROUGH...HELPING TO RE-ENFORCE LOW LEVEL COLD AIR...THEN DRY BY
MONDAY AS WEAK RIDGING TO ZONAL FLOW BUILDS IN.
FOR TEMPERATURES FROM THURSDAY NIGHT ON...BLENDED MEX ENSEMBLE MEAN
WITH HPC GUIDANCE...AND TWEAKED TOWARDS 12Z ECMWF LOW LEVEL THERMAL
FIELDS. AFTER ABOVE NORMAL TEMPERATURES THURSDAY
NIGHT-FRIDAY...FORECASTING NEAR NORMAL TEMPERATURES FRIDAY
NIGHT-SATURDAY NIGHT...THEN BELOW NORMAL TEMPERATURES SUNDAY-MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
HIGH PRES CONTINUES TO MOVE OFFSHORE TONIGHT AS LOW PRES PASSES S
OF LONG ISLAND. THIS LOW WILL STRENGTHEN AS IT MOVES OUT TO SEA
AS ANOTHER MOVES ACROSS SE CANADA ON TUE RESULTING IN INCREASING
W-NW WINDS WHILE ANOTHER AREA OF HIGH PRES APPROACHES FROM THE
WEST.
CIGS HAVE DROPPED TO LOW VFR. A PERIOD OF MVFR CIGS IS NOW
EXPECTED AT COASTAL TERMINALS THROUGH 10Z OR 11Z BASED ON UPSTREAM
OBS...BUT SHOULD REMAIN ABOVE 2K FT. ONE OTHER EXCEPTION IS
BETWEEN 11Z AND 14Z WHERE AN INCREASE IN LOW LEVEL MOISTURE AND
SHARP LOW LEVEL INVERSION MAY PRODUCE A PERIOD OF LOW MVFR OR EVEN
IFR CIGS. MODELS HAVE BEEN FLIP FLOPPING ON THIS AND CONFIDENCE
REMAINS LOW...THEREFORE CONTINUED WITH THE SCT CLOUD GROUP.
PRECIP ASSOCIATED WITH LOW PASSING TO THE S IS
REMAINING S AS EXPECTED. COULD SEE A FEW FLURRIES OVERNIGHT AS AN
UPPER DISTURBANCE MOVES THROUGH...BUT NOT EXPECTING THIS TO CAUSE
ADDITIONAL RESTRICTIONS.
WINDS INCREASE TUE AFTN AS THE PRES GRADIENT TIGHTENS WITH THE LOW
STRENGTHENING AS IT MOVES OUT TO SEA AND ANOTHER MOVES ACROSS SE
CANADA. GUSTS INTO THE LOWER 20S ARE EXPECTED AFT 16Z AND PK WINDS
MAY OCNLY REACH 25 KT.
NYC TERMINALS: DIRECTIONS WILL BE RIGHT AROUND 300 DEGREES TRUE
BETWEEN 18Z AND 00Z...THEN VEER TO THE RIGHT OF 300.
OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...
TUE NIGHT-WED...VFR.
WED NIGHT-THU...OCNL IFR IN RAIN. GUSTY NE-E WINDS.
FRI...CHANCE FOR IFR OR MVFR IN SNOW SHOWERS. GUSTY NW-W WINDS.
SAT...VFR. GUSTY NW-W WINDS.
&&
.MARINE...
LIGHT WINDS EXPECTED FROM THE SOUTHWEST TONIGHT. AN AREA OF LOW
PRESSURE WILL PASS WELL OFFSHORE LATE TONIGHT...THEN THE PRESSURE
GRADIENT TIGHTENS TUESDAY MORNING WITH HIGH PRESSURE BUILDING IN
FROM THE WEST BEHIND THE STORM AS WELL AS BEHIND ANOTHER AREA OF LOW
PRESSURE MOVING ACROSS EASTERN CANADA. GUSTS TO 25 KTS ARE EXPECTED
TO DEVELOP ON THE OCEAN WATERS AND EASTERN LONG ISLAND SOUND BY
MIDDAY ON TUESDAY...AND LAST INTO THE EVENING HOURS WITH COLD AIR
ADVECTION. SEAS EXPECTED TO BUILD TO 5 FT OVER ANZ353 AND
ANZ350...BUT PROBABLY ENDS UP JUST BELOW IT AT ANZ355. PERHAPS
EASTERNMOST PORTIONS OF ANZ355 COULD TOUCH 5 FT AT TIMES. THE
PRESSURE GRADIENT RELAXES LATER ON TUESDAY NIGHT...WITH SCA
CONDITIONS COMING TO AN END ACROSS ALL WATERS.
SUB-SMALL CRAFT CONDITIONS ON WEDNESDAY...GIVE WAY TO RAPIDLY
BUILDING WINDS AND SEAS WEDNESDAY NIGHT...DUE TO APPROACHING COASTAL
LOW. COULD SEE GUSTS TO GALE FORCE LATE WEDNESDAY NIGHT...DEPENDING
ON HOW MUCH OF 40-50 KT 950-925 HPA JET MIXES DOWN. COASTAL LOW
TRACKS TO THE S THURSDAY...WITH POTENTIAL FOR GALES THROUGH AT LEAST
THE MORNING HOURS. SMALL CRAFT ADVISORY CONDITIONS THEN EXPECTED TO
LINGER...ESPECIALLY ON THE COASTAL OCEAN/EASTERN WATERS INTO FRIDAY.
ALL WATERS SHOULD FALL BELOW SCA LEVELS SATURDAY AS HIGH PRESSURE
GRADUALLY BUILDS IN.
&&
.HYDROLOGY...
A TRACE TO A FEW HUNDREDTHS OF LIQUID EQUIVALENT IS POSSIBLE TNGT
ACROSS LONG ISLAND AND SOUTHEASTERN CONNECTICUT.
THERE IS THE POTENTIAL FOR LOCALLY HEAVY RAINFALL FROM LATE
WEDNESDAY NIGHT INTO THURSDAY MORNING. FOR NOW FORECASTING GENERALLY
FROM 1/2-3/4 AN INCH OF RAINFALL WEDNESDAY NIGHT/THURSDAY...BUT
DEPENDING ON EXACTLY WHERE THE HEAVIEST RAINBANDS SET UP LATE
WEDNESDAY NIGHT/THURSDAY MORNING...SOME LOCATIONS COULD SEE UP TO
DOUBLE THAT...AND MAYBE A BIT MORE. SO WHILE FOR THE MOST PART...AT
MOST MINOR POOR DRAINAGE/URBAN FLOODING IS EXPECTED...THERE COULD BE
LOCALIZED FLOODING OF POOR DRAINING/URBAN AREAS IF THEY ARE UNDER
THE HEAVIEST RAINBANDS. AT THIS TIME IT IS TOO SOON TO PINPOINT THE
EXACT LOCATIONS THESE RAINBANDS WILL FORM OVER...JUST THAT
CONDITIONS ARE FORECAST TO EXIST THAT ARE CONDUCIVE TO THEIR
FORMATION OVER SOME PORTION OF THE TRI-STATE LATE WEDNESDAY
NIGHT/THURSDAY MORNING.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM EST THIS
EVENING FOR ANZ330-355.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 1 AM EST
WEDNESDAY FOR ANZ350-353.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
444 AM EST TUE JAN 10 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION TODAY. LOW PRESSURE WILL
TRACK INTO EAST TENNESSEE TUESDAY NIGHT BEFORE AFFECTING THE MID-
ATLANTIC REGION WEDNESDAY AND WEDNESDAY NIGHT. A COLD FRONT IS
EXPECTED TO CROSS THE REGION THURSDAY...USHERING IN MUCH COLDER
AIR FOR THE REGION.
&&
.NEAR TERM /TODAY/...
AS WRITTEN EARLIER - FOG/LOW CLDS ARE THE MAIN CONCERN OF THE
OVRNGT HRS. AS QUITE A FEW AVIATION OBS ARE COMING IN BLO 1/2 MI
W OF I-95 TO I-81 I`VE BEEN SCANNING THE TRAFFIC CAMS...AND THERE
IS A WIDE VARIANCE IN VSBYS - FM 1/2 MI IN FOG TO CRYSTAL CLR. WE
HV REISSUED AN SPS FOR PATCHY DENSE FOG ALONG W/ PTNL FOR ICY
SPOTS ON BRIDGES/OVRPASSES GIVEN AIR TEMPS HOVERING ARND THE FRZG
MARK. WE`LL RMN VIGILANT OVR THE NEXT FEW HRS...AND ISSUE A DENSE
FOG ADVSRY IF NEEDED B4 THE BULK OF COMMUTERS TAKE TO THE ROADS.
AS OF NOW - IF THAT HAPPENS AN ADVSRY WOULD NOT INCLUDE THE
495/95/695 CORRIDOR.
PRVS DSCN (326 AM)...
ATTM WE ARE KEEPING OUR EYES ON FOG AND LOW CLD. ON IR STLT IT IS
NOT IMMEDIATELY CLR WHERE THE CLDS ARE - BEST TO USE 11-3.9 MU
OVERLAIN W/ CIG/VSBY...AS WELL AS GO OUT AND LOOK AT THE SKY (AT
LEAST LOCALLY). BUT IT DOES APPEAR THAT DRIER AIR IS MOVG INTO THE
AREA AS W OF THE BLUE RDG NOT REPORTING ANY CLDS WHILE E OF THE
MTNS ARE SOCKED IN W/ OVC SKIES. IN A WAY THAT IS A BLESSING AS
THE LOW CLDS ARE PREVENTING THE RAD CONDS THAT COULD FACILITATE
DENSE FOG - E OF MTNS VSBYS GNRLY IN 2-4 MI RANGE ATTM WITH A FEW
OUTLIERS AT EITHER END OF THE SPECTRUM.
THERE WAS SOME WETNESS OVR MUCH OF THE CWA MON...AND THERE`LL BE
MORE ON WED...BUT TDA SHOULD BE DRY AS HIGH PRES MOVES INTO THE
AREA. WRLY WINDS WL BE DOWNSLOPING..AND IT SHOULDN`T BE LONG THIS
MRNG B4 THE SNOW THAT FELL MON IS GONE. TEMPS SHOULD TOP OUT IN
THE U40S/L50S W/ XCPTN OF M40S IN THE HIGHLANDS.
&&
.SHORT TERM /TONIGHT/...
THE EVE HRS SHOULD GNRLY BE CLR..ALLOWING TEMPS TO DROP THRU THE
40S FAIRLY QUICKLY. CLDS WL BEGIN TO INCRS AFTR MDNGT IN HIGHLAND/
PENDLETON AS THE NEXT SHORT WV TRACKS ACROSS THE GULF STATES.
BECAUSE OF THE INCRSG CLDS TEMPS WON`T GET QUITE AS COLD IN THE
CENTRAL SHEN VLLY AS THEY WL NEAR THE MASON-DIXON LN. TEMPS WL
RANGE FM THE MU20S N TO M30S S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A COUPLE OF VERY DIFFERENT BUT COMPLEX LOW PRESSURE SYSTEMS WILL
MERGE JUST NORTH OF THE AREA MID WEEK. BEFORE THEN...AND OVER THE
NEXT 2 DAYS - THESE WILL BE MAKING THEIR WAY TO THE MID ATLC /ONE
FROM THE NRN PLAINS AND ONE FROM THE SRN PLAINS/. THE SRN PLAINS
SYSTEM WILL BRING STEADY RAINS TO THE AREA ON WED-EARLY
THU...ARRIVING JUST AHEAD OF THE DRIER AND COLDER NRN PLAINS
SYSTEM. BOTH CLOSED UPPER LOWS WILL STRENGTHEN OVER THE NEXT 24-36
HRS AS THEY APPROACH OUR AREA. THE SRN PLAINS LOW THAT HAS ALREADY
SPREAD MODERATE TO HEAVY RAINFALL FROM TX/OK TO THE MISSISSIPPI
VLY WILL CONTINUE TO DEEPEN AS IT MOVES DUE EAST TODAY.
BY EARLY WED...THE NRN PLAINS LOW WILL QUICKLY DROP SWD AND PUSH THE
SRN PLAINS LOW RIGHT UP THE ERN SEABOARD ONCE IT REACHES THE APLCNS.
BEFORE THEN...THE LOW WILL HAVE TAPPED INTO A BETTER GULF MOISTURE
FETCH AS BEGIN TO PULL THAT LOW LEVEL MOISTURE UP ACROSS THE
CAROLINAS AND THE LEE SIDE OF THE BLUE RIDGE. DRIER WLY WINDS FROM
TODAY AND TONIGHT WILL KEEP THE LOW LEVEL CONDITIONS FAVORABLE FOR A
RAIN-SNOW MIX AT ONSET OF PRECIP AFTER DAWN ON WED. AS THE SFC LOW
STRENGTHENS AND DRIFTS UP THE I-95 CORRIDOR...RELATIVELY WARMER AND
MORE MOIST ELY ONSHORE FLOW WILL HELP TEMPER THESE LOW LEVEL
CONDITIONS AND MAKE FOR MORE OF A COLD RAIN HEADING INTO THE AFTN
HRS. STEADY BATCHES OF RAIN WILL MOVE OVER THE REGION LATER IN THE
DAY AND ESPECIALLY FOR THE LATE NIGHT HRS. AVG MODEL QPFS RANGE IN
THE 0.50-1.00 INCH RANGE W/ LOCALLY HIGHER AMNTS ALONG AND E OF
I-95. MUCH OF THIS WILL BE STRETCHED OUT OVER A BETTER PART OF THE
DAY/EVE.
THE NRN PLAINS UPPER LOW WILL THEN KICK OUT THIS SYSTEM QUICKLY UP
ACROSS THE SRN NEW ENGLAND COAST. BY EARLY THU...PRECIP WILL BE
DISSIPATING OVER THE PIEDMONT BUT ANOTHER COLD SURGE WILL BE RIGHT
ON ITS HEELS. AS THE NEW ENGLAND SYSTEM RACES OFF THE COAST...THE
GREAT LAKES UPPER LOW WILL HAVE A COUPLE MORE DAYS TO SLOWLY ROTATE
EWD. COLDER AND DRIER CANADIAN AIR WILL BE ON THE WAY...THOUGH NOT
AS COLD AS OUR RECENT BOUT. CONDITIONS TO CLOSE OUT THE WEEK WILL BE
BLUSTERY AND COLD...W/ A RETURN TO THE DRIER AIR OF DEWPOINTS IN THE
SINGLE DIGITS AND TEENS AGAIN. THIS SYSTEM WILL MAKE AN EXIT OFF THE
COAST ON SAT...BUT ANOTHER REINFORCING SHOT OF COLD-DRY AIR WILL
COME IN FROM BEHIND ON SUN. A GRADUAL RETURN TO MORE MILD CONDITIONS
/THOUGH STILL MAINLY DRY/ FOR EARLY NEXT WEEK.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
LOW VSBYS IN FOG AT THE SITES OUTSIDE OF THE MAJOR CITIES. THESE
ARE XPCTD TO IMPROVE THIS MRNG AS HIGH BUILDS INTO THE MID ATLC.
ATTM IAD...CHO...MRB ALL XPRNCG VSBYS UNDER 1SM. RUC BUFKIT
TEMP/DWPT PROFILES SHOW LOW LVL MOISTURE COLUMN THINNING 1ST AT
MRB ARND SUNRISE...THEN E OF THE MTNS BTWN 8 AND 9 AM. VFR CONDS
XPCTD AT ALL SITES THEREAFTER THROUGH THE DAYLGT HRS AND TNGT.
HIGH CLDS WL BEGIN TO OVRSPREAD FM THE SW AFTR MDNGT.
A LOW PRESSURE SYSTEM WILL QUICKLY SLIDE UP ACROSS THE AREA FROM THE
SW...FROM LATE MRNG WED THROUGH MIDDAY THU. MAINLY PERIODS OF RAIN
W/ BREEZY LOW LEVEL WINDS CLOSER TO THE MD BAY/DELMARVA. THE LOW
WILL MOVE NE ON THU...W/ A COUPLE OF BREEZY AND DRY UPPER LEVEL
SYSTEMS READY TO MOVE DOWN ACROSS THE REGION TO END THE WEEK. HIGH
PRESSURE WILL BEGIN IN FOR THE EARLY PART OF NEXT WEEK.
&&
.MARINE...
HV REISSUED THE SML CRFT ADVSRY TO INCLUDE ALL OF THE WATERS FOR
THE AFTN HRS. HIGH PRES BLDG INTO THE WATERS WL CAUSE A PD OF
15-20 KT WINDS. NO PROBS THIS MRNG OR TNGT.
A LOW PRESSURE SYSTEM WILL MOVE TOWARD THE AREA TODAY AND EARLY WED.
SCA CONDITIONS EXPECTED OVERNIGHT WED NIGHT INTO EARLY THU...AS A
STRENGTHENING SFC LOW DRIFTS UP THE I-95 CORRIDOR TOWARD THE LOWER
MD BAY/TP. THIS RAINY SYSTEM WILL RACE TOWARD NEW ENGLAND EARLY
THU...WHILE A COUPLE OF DRY AND BREEZY UPPER WAVES GEAR UP TO SWING
OVER THE AREA. THESE UPPER LEVEL FEATURES WILL BRING SCA CONDITIONS
TO THE AREA TO END THE WEEK.
&&
.TIDES/COASTAL FLOODING...
LOW PRESSURE APPROACHES AREA WED...AND PASSES NE OF REGION EARLY
THU. THERE WL BE A PERIOD OF STRONG ELY FLOW WED NIGHT...WHEN
TIDAL DEPARTURES MAY INCREASE BY A FT OR MORE. WE`RE JUST PAST
FULL MOON...SO THERE WL BE A TIDAL CONTRIBUTION AS WELL. MAY GET
CLOSE TO MINOR THRESHOLDS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EST THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 AM EST THURSDAY
FOR ANZ530>534-537>543.
&&
$$
PRODUCTS...WOODY!/GMS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
326 AM EST TUE JAN 10 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION TODAY. LOW PRESSURE WILL
TRACK INTO EAST TENNESSEE TUESDAY NIGHT BEFORE AFFECTING THE MID-
ATLANTIC REGION WEDNESDAY AND WEDNESDAY NIGHT. A COLD FRONT IS
EXPECTED TO CROSS THE REGION THURSDAY...USHERING IN MUCH COLDER
AIR FOR THE REGION.
&&
.NEAR TERM /TODAY/...
ATTM WE ARE KEEPING OUR EYES ON FOG AND LOW CLD. ON IR STLT IT IS
NOT IMMEDIATELY CLR WHERE THE CLDS ARE - BEST TO USE 11-3.9 MU
OVERLAIN W/ CIG/VSBY...AS WELL AS GO OUT AND LOOK AT THE SKY (AT
LEAST LOCALLY). BUT IT DOES APPEAR THAT DRIER AIR IS MOVG INTO THE
AREA AS W OF THE BLUE RDG NOT REPORTING ANY CLDS WHILE E OF THE
MTNS ARE SOCKED IN W/ OVC SKIES. IN A WAY THAT IS A BLESSING AS
THE LOW CLDS ARE PREVENTING THE RAD CONDS THAT COULD FACILITATE
DENSE FOG - E OF MTNS VSBYS GNRLY IN 2-4 MI RANGE ATTM WITH A FEW
OUTLIERS AT EITHER END OF THE SPECTRUM.
THERE WAS SOME WETNESS OVR MUCH OF THE CWA MON...AND THERE`LL BE
MORE ON WED...BUT TDA SHOULD BE DRY AS HIGH PRES MOVES INTO THE
AREA. WRLY WINDS WL BE DOWNSLOPING..AND IT SHOULDN`T BE LONG THIS
MRNG B4 THE SNOW THAT FELL MON IS GONE. TEMPS SHOULD TOP OUT IN
THE U40S/L50S W/ XCPTN OF M40S IN THE HIGHLANDS.
&&
.SHORT TERM /TONIGHT/...
THE EVE HRS SHOULD GNRLY BE CLR..ALLOWING TEMPS TO DROP THRU THE
40S FAIRLY QUICKLY. CLDS WL BEGIN TO INCRS AFTR MDNGT IN HIGHLAND/
PENDLETON AS THE NEXT SHORT WV TRACKS ACROSS THE GULF STATES.
BECAUSE OF THE INCRSG CLDS TEMPS WON`T GET QUITE AS COLD IN THE
CENTRAL SHEN VLLY AS THEY WL NEAR THE MASON-DIXON LN. TEMPS WL
RANGE FM THE MU20S N TO M30S S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A COUPLE OF VERY DIFFERENT BUT COMPLEX LOW PRESSURE SYSTEMS WILL
MERGE JUST NORTH OF THE AREA MID WEEK. BEFORE THEN...AND OVER THE
NEXT 2 DAYS - THESE WILL BE MAKING THEIR WAY TO THE MID ATLC /ONE
FROM THE NRN PLAINS AND ONE FROM THE SRN PLAINS/. THE SRN PLAINS
SYSTEM WILL BRING STEADY RAINS TO THE AREA ON WED-EARLY
THU...ARRIVING JUST AHEAD OF THE DRIER AND COLDER NRN PLAINS
SYSTEM. BOTH CLOSED UPPER LOWS WILL STRENGTHEN OVER THE NEXT 24-36
HRS AS THEY APPROACH OUR AREA. THE SRN PLAINS LOW THAT HAS ALREADY
SPREAD MODERATE TO HEAVY RAINFALL FROM TX/OK TO THE MISSISSIPPI
VLY WILL CONTINUE TO DEEPEN AS IT MOVES DUE EAST TODAY.
BY EARLY WED...THE NRN PLAINS LOW WILL QUICKLY DROP SWD AND PUSH THE
SRN PLAINS LOW RIGHT UP THE ERN SEABOARD ONCE IT REACHES THE APLCNS.
BEFORE THEN...THE LOW WILL HAVE TAPPED INTO A BETTER GULF MOISTURE
FETCH AS BEGIN TO PULL THAT LOW LEVEL MOISTURE UP ACROSS THE
CAROLINAS AND THE LEE SIDE OF THE BLUE RIDGE. DRIER WLY WINDS FROM
TODAY AND TONIGHT WILL KEEP THE LOW LEVEL CONDITIONS FAVORABLE FOR A
RAIN-SNOW MIX AT ONSET OF PRECIP AFTER DAWN ON WED. AS THE SFC LOW
STRENGTHENS AND DRIFTS UP THE I-95 CORRIDOR...RELATIVELY WARMER AND
MORE MOIST ELY ONSHORE FLOW WILL HELP TEMPER THESE LOW LEVEL
CONDITIONS AND MAKE FOR MORE OF A COLD RAIN HEADING INTO THE AFTN
HRS. STEADY BATCHES OF RAIN WILL MOVE OVER THE REGION LATER IN THE
DAY AND ESPECIALLY FOR THE LATE NIGHT HRS. AVG MODEL QPFS RANGE IN
THE 0.50-1.00 INCH RANGE W/ LOCALLY HIGHER AMNTS ALONG AND E OF
I-95. MUCH OF THIS WILL BE STRETCHED OUT OVER A BETTER PART OF THE
DAY/EVE.
THE NRN PLAINS UPPER LOW WILL THEN KICK OUT THIS SYSTEM QUICKLY UP
ACROSS THE SRN NEW ENGLAND COAST. BY EARLY THU...PRECIP WILL BE
DISSIPATING OVER THE PIEDMONT BUT ANOTHER COLD SURGE WILL BE RIGHT
ON ITS HEELS. AS THE NEW ENGLAND SYSTEM RACES OFF THE COAST...THE
GREAT LAKES UPPER LOW WILL HAVE A COUPLE MORE DAYS TO SLOWLY ROTATE
EWD. COLDER AND DRIER CANADIAN AIR WILL BE ON THE WAY...THOUGH NOT
AS COLD AS OUR RECENT BOUT. CONDITIONS TO CLOSE OUT THE WEEK WILL BE
BLUSTERY AND COLD...W/ A RETURN TO THE DRIER AIR OF DEWPOINTS IN THE
SINGLE DIGITS AND TEENS AGAIN. THIS SYSTEM WILL MAKE AN EXIT OFF THE
COAST ON SAT...BUT ANOTHER REINFORCING SHOT OF COLD-DRY AIR WILL
COME IN FROM BEHIND ON SUN. A GRADUAL RETURN TO MORE MILD CONDITIONS
/THOUGH STILL MAINLY DRY/ FOR EARLY NEXT WEEK.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
LOW VSBYS IN FOG AT THE SITES OUTSIDE OF THE MAJOR CITIES. THESE
ARE XPCTD TO IMPROVE THIS MRNG AS HIGH BUILDS INTO THE MID ATLC.
ATTM IAD...CHO...MRB ALL XPRNCG VSBYS UNDER 1SM. RUC BUFKIT
TEMP/DWPT PROFILES SHOW LOW LVL MOISTURE COLUMN THINNING 1ST AT
MRB ARND SUNRISE...THEN E OF THE MTNS BTWN 8 AND 9 AM. VFR CONDS
XPCTD AT ALL SITES THEREAFTER THROUGH THE DAYLGT HRS AND TNGT.
HIGH CLDS WL BEGIN TO OVRSPREAD FM THE SW AFTR MDNGT.
A LOW PRESSURE SYSTEM WILL QUICKLY SLIDE UP ACROSS THE AREA FROM THE
SW...FROM LATE MRNG WED THROUGH MIDDAY THU. MAINLY PERIODS OF RAIN
W/ BREEZY LOW LEVEL WINDS CLOSER TO THE MD BAY/DELMARVA. THE LOW
WILL MOVE NE ON THU...W/ A COUPLE OF BREEZY AND DRY UPPER LEVEL
SYSTEMS READY TO MOVE DOWN ACROSS THE REGION TO END THE WEEK. HIGH
PRESSURE WILL BEGIN IN FOR THE EARLY PART OF NEXT WEEK.
&&
.MARINE...
HV REISSUED THE SML CRFT ADVSRY TO INCLUDE ALL OF THE WATERS FOR
THE AFTN HRS. HIGH PRES BLDG INTO THE WATERS WL CAUSE A PD OF
15-20 KT WINDS. NO PROBS THIS MRNG OR TNGT.
A LOW PRESSURE SYSTEM WILL MOVE TOWARD THE AREA TODAY AND EARLY WED.
SCA CONDITIONS EXPECTED OVERNIGHT WED NIGHT INTO EARLY THU...AS A
STRENGTHENING SFC LOW DRIFTS UP THE I-95 CORRIDOR TOWARD THE LOWER
MD BAY/TP. THIS RAINY SYSTEM WILL RACE TOWARD NEW ENGLAND EARLY
THU...WHILE A COUPLE OF DRY AND BREEZY UPPER WAVES GEAR UP TO SWING
OVER THE AREA. THESE UPPER LEVEL FEATURES WILL BRING SCA CONDITIONS
TO THE AREA TO END THE WEEK.
&&
.TIDES/COASTAL FLOODING...
LOW PRESSURE APPROACHES AREA WED...AND PASSES NE OF REGION EARLY
THU. THERE WL BE A PERIOD OF STRONG ELY FLOW WED NIGHT...WHEN
TIDAL DEPARTURES MAY INCREASE BY A FT OR MORE. WE`RE JUST PAST
FULL MOON...SO THERE WL BE A TIDAL CONTRIBUTION AS WELL. MAY GET
CLOSE TO MINOR THRESHOLDS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EST THIS EVENING
FOR ANZ530>543.
&&
$$
PRODUCTS...WOODY!/GMS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
642 AM EST TUE JAN 10 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION TODAY. LOW PRESSURE WILL
TRACK INTO EAST TENNESSEE TUESDAY NIGHT BEFORE AFFECTING THE MID-
ATLANTIC REGION WEDNESDAY AND WEDNESDAY NIGHT. A COLD FRONT IS
EXPECTED TO CROSS THE REGION THURSDAY...USHERING IN MUCH COLDER
AIR FOR THE REGION.
&&
.NEAR TERM /TODAY/...
IT`S BEEN A VERY BUSY NGT. DENSE FOG ADVSRY WAS ISSUED AT 520
AM BTWN 1-95 AND I-81 THRU 9 AM...BUT NOW VSBYS ARE IMPRVG AS WRLY
WINDS MOVE E OF THE MTNS. PLAN WL BE TO LV ADSRY IN EFFECT BUT LET
ONCOMING DAYSHIFT REEVALUATE AND CANX EARLY IF CONDTIONS WARRANT.
**
(444 AM DSCN)
AS WRITTEN EARLIER - FOG/LOW CLDS ARE THE MAIN CONCERN OF THE
OVRNGT HRS. AS QUITE A FEW AVIATION OBS ARE COMING IN BLO 1/2 MI
W OF I-95 TO I-81 I`VE BEEN SCANNING THE TRAFFIC CAMS...AND THERE
IS A WIDE VARIANCE IN VSBYS - FM 1/2 MI IN FOG TO CRYSTAL CLR. WE
HV REISSUED AN SPS FOR PATCHY DENSE FOG ALONG W/ PTNL FOR ICY
SPOTS ON BRIDGES/OVRPASSES GIVEN AIR TEMPS HOVERING ARND THE FRZG
MARK. WE`LL RMN VIGILANT OVR THE NEXT FEW HRS...AND ISSUE A DENSE
FOG ADVSRY IF NEEDED B4 THE BULK OF COMMUTERS TAKE TO THE ROADS.
AS OF NOW - IF THAT HAPPENS AN ADVSRY WOULD NOT INCLUDE THE
495/95/695 CORRIDOR.
PRVS DSCN (326 AM)...
ATTM WE ARE KEEPING OUR EYES ON FOG AND LOW CLD. ON IR STLT IT IS
NOT IMMEDIATELY CLR WHERE THE CLDS ARE - BEST TO USE 11-3.9 MU
OVERLAIN W/ CIG/VSBY...AS WELL AS GO OUT AND LOOK AT THE SKY (AT
LEAST LOCALLY). BUT IT DOES APPEAR THAT DRIER AIR IS MOVG INTO THE
AREA AS W OF THE BLUE RDG NOT REPORTING ANY CLDS WHILE E OF THE
MTNS ARE SOCKED IN W/ OVC SKIES. IN A WAY THAT IS A BLESSING AS
THE LOW CLDS ARE PREVENTING THE RAD CONDS THAT COULD FACILITATE
DENSE FOG - E OF MTNS VSBYS GNRLY IN 2-4 MI RANGE ATTM WITH A FEW
OUTLIERS AT EITHER END OF THE SPECTRUM.
THERE WAS SOME WETNESS OVR MUCH OF THE CWA MON...AND THERE`LL BE
MORE ON WED...BUT TDA SHOULD BE DRY AS HIGH PRES MOVES INTO THE
AREA. WRLY WINDS WL BE DOWNSLOPING..AND IT SHOULDN`T BE LONG THIS
MRNG B4 THE SNOW THAT FELL MON IS GONE. TEMPS SHOULD TOP OUT IN
THE U40S/L50S W/ XCPTN OF M40S IN THE HIGHLANDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE EVE HRS SHOULD GNRLY BE CLR..ALLOWING TEMPS TO DROP THRU THE
40S FAIRLY QUICKLY. CLDS WL BEGIN TO INCRS AFTR MDNGT IN HIGHLAND/
PENDLETON AS THE NEXT SHORT WV TRACKS ACROSS THE GULF STATES.
BECAUSE OF THE INCRSG CLDS TEMPS WON`T GET QUITE AS COLD IN THE
CENTRAL SHEN VLLY AS THEY WL NEAR THE MASON-DIXON LN. TEMPS WL
RANGE FM THE MU20S N TO M30S S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A COUPLE OF VERY DIFFERENT BUT COMPLEX LOW PRESSURE SYSTEMS WILL
MERGE JUST NORTH OF THE AREA MID WEEK. BEFORE THEN...AND OVER THE
NEXT 2 DAYS - THESE WILL BE MAKING THEIR WAY TO THE MID ATLC /ONE
FROM THE NRN PLAINS AND ONE FROM THE SRN PLAINS/. THE SRN PLAINS
SYSTEM WILL BRING STEADY RAINS TO THE AREA ON WED-EARLY
THU...ARRIVING JUST AHEAD OF THE DRIER AND COLDER NRN PLAINS
SYSTEM. BOTH CLOSED UPPER LOWS WILL STRENGTHEN OVER THE NEXT 24-36
HRS AS THEY APPROACH OUR AREA. THE SRN PLAINS LOW THAT HAS ALREADY
SPREAD MODERATE TO HEAVY RAINFALL FROM TX/OK TO THE MISSISSIPPI
VLY WILL CONTINUE TO DEEPEN AS IT MOVES DUE EAST TODAY.
BY EARLY WED...THE NRN PLAINS LOW WILL QUICKLY DROP SWD AND PUSH THE
SRN PLAINS LOW RIGHT UP THE ERN SEABOARD ONCE IT REACHES THE APLCNS.
BEFORE THEN...THE LOW WILL HAVE TAPPED INTO A BETTER GULF MOISTURE
FETCH AS BEGIN TO PULL THAT LOW LEVEL MOISTURE UP ACROSS THE
CAROLINAS AND THE LEE SIDE OF THE BLUE RIDGE. DRIER WLY WINDS FROM
TODAY AND TONIGHT WILL KEEP THE LOW LEVEL CONDITIONS FAVORABLE FOR A
RAIN-SNOW MIX AT ONSET OF PRECIP AFTER DAWN ON WED. AS THE SFC LOW
STRENGTHENS AND DRIFTS UP THE I-95 CORRIDOR...RELATIVELY WARMER AND
MORE MOIST ELY ONSHORE FLOW WILL HELP TEMPER THESE LOW LEVEL
CONDITIONS AND MAKE FOR MORE OF A COLD RAIN HEADING INTO THE AFTN
HRS. STEADY BATCHES OF RAIN WILL MOVE OVER THE REGION LATER IN THE
DAY AND ESPECIALLY FOR THE LATE NIGHT HRS. AVG MODEL QPFS RANGE IN
THE 0.50-1.00 INCH RANGE W/ LOCALLY HIGHER AMNTS ALONG AND E OF
I-95. MUCH OF THIS WILL BE STRETCHED OUT OVER A BETTER PART OF THE
DAY/EVE.
THE NRN PLAINS UPPER LOW WILL THEN KICK OUT THIS SYSTEM QUICKLY UP
ACROSS THE SRN NEW ENGLAND COAST. BY EARLY THU...PRECIP WILL BE
DISSIPATING OVER THE PIEDMONT BUT ANOTHER COLD SURGE WILL BE RIGHT
ON ITS HEELS. AS THE NEW ENGLAND SYSTEM RACES OFF THE COAST...THE
GREAT LAKES UPPER LOW WILL HAVE A COUPLE MORE DAYS TO SLOWLY ROTATE
EWD. COLDER AND DRIER CANADIAN AIR WILL BE ON THE WAY...THOUGH NOT
AS COLD AS OUR RECENT BOUT. CONDITIONS TO CLOSE OUT THE WEEK WILL BE
BLUSTERY AND COLD...W/ A RETURN TO THE DRIER AIR OF DEWPOINTS IN THE
SINGLE DIGITS AND TEENS AGAIN. THIS SYSTEM WILL MAKE AN EXIT OFF THE
COAST ON SAT...BUT ANOTHER REINFORCING SHOT OF COLD-DRY AIR WILL
COME IN FROM BEHIND ON SUN. A GRADUAL RETURN TO MORE MILD CONDITIONS
/THOUGH STILL MAINLY DRY/ FOR EARLY NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
LOW VSBYS IN FOG AT THE SITES OUTSIDE OF THE MAJOR CITIES. THESE
ARE XPCTD TO IMPROVE THIS MRNG AS HIGH BUILDS INTO THE MID ATLC.
ATTM IAD...CHO...MRB ALL XPRNCG VSBYS UNDER 1SM. RUC BUFKIT
TEMP/DWPT PROFILES SHOW LOW LVL MOISTURE COLUMN THINNING 1ST AT
MRB ARND SUNRISE...THEN E OF THE MTNS BTWN 8 AND 9 AM. VFR CONDS
XPCTD AT ALL SITES THEREAFTER THROUGH THE DAYLGT HRS AND TNGT.
HIGH CLDS WL BEGIN TO OVRSPREAD FM THE SW AFTR MDNGT.
A LOW PRESSURE SYSTEM WILL QUICKLY SLIDE UP ACROSS THE AREA FROM THE
SW...FROM LATE MRNG WED THROUGH MIDDAY THU. MAINLY PERIODS OF RAIN
W/ BREEZY LOW LEVEL WINDS CLOSER TO THE MD BAY/DELMARVA. THE LOW
WILL MOVE NE ON THU...W/ A COUPLE OF BREEZY AND DRY UPPER LEVEL
SYSTEMS READY TO MOVE DOWN ACROSS THE REGION TO END THE WEEK. HIGH
PRESSURE WILL BEGIN IN FOR THE EARLY PART OF NEXT WEEK.
&&
.MARINE...
HV REISSUED THE SML CRFT ADVSRY TO INCLUDE ALL OF THE WATERS FOR
THE AFTN HRS. HIGH PRES BLDG INTO THE WATERS WL CAUSE A PD OF
15-20 KT WINDS. NO PROBS THIS MRNG OR TNGT.
A LOW PRESSURE SYSTEM WILL MOVE TOWARD THE AREA TODAY AND EARLY WED.
SCA CONDITIONS EXPECTED OVERNIGHT WED NIGHT INTO EARLY THU...AS A
STRENGTHENING SFC LOW DRIFTS UP THE I-95 CORRIDOR TOWARD THE LOWER
MD BAY/TP. THIS RAINY SYSTEM WILL RACE TOWARD NEW ENGLAND EARLY
THU...WHILE A COUPLE OF DRY AND BREEZY UPPER WAVES GEAR UP TO SWING
OVER THE AREA. THESE UPPER LEVEL FEATURES WILL BRING SCA CONDITIONS
TO THE AREA TO END THE WEEK.
&&
.TIDES/COASTAL FLOODING...
LOW PRESSURE APPROACHES AREA WED...AND PASSES NE OF REGION EARLY
THU. THERE WL BE A PERIOD OF STRONG ELY FLOW WED NIGHT...WHEN
TIDAL DEPARTURES MAY INCREASE BY A FT OR MORE. WE`RE JUST PAST
FULL MOON...SO THERE WL BE A TIDAL CONTRIBUTION AS WELL. MAY GET
CLOSE TO MINOR THRESHOLDS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR MDZ003>005-
009-010.
VA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ025>031-
036>040-042-050>053-501-502.
WV...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR WVZ052-053.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EST THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 AM EST THURSDAY
FOR ANZ530>534-537>543.
&&
$$
PRODUCTS...WOODY!/GMS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
351 AM MST TUE JAN 10 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWING A REX BLOCK
UPPER LEVEL FLOW PATTERN ACROSS THE CONUS. THE CUT-OFF UPPER LOW
CENTER IS SPINNING OVER EASTERN TEXAS AND SETTING OFF
THUNDERSTORMS OVER THE RED RIVER REGION AND THE NORTHERN GULF
SHORES. AN ELONGATE BUT RELATIVELY CALM UPPER TROUGH IS MOVING
OVER NEW ENGLAND. UPPER LEVEL ZONAL FLOW IS IN PLACE OVER THE
NORTHERN HIGH PLAINS...NORTH OF THE CUT-OFF LOW. SHORT WAVE
RIDGING FAVORS THE FAR SOUTHWESTERN CONUS. A NEW UPPER LEVEL TROUGH
HAS MOVED ON SHORE OVER THE PACIFIC NORTHWEST.
THIS APPROACHING WESTERN TROUGH IS PUSHING A FAIR AMOUNT OF
PACIFIC MOISTURE ALONG AND AHEAD OF IT OVER THE NORTHERN ROCKIES.
IT ALSO SHOWS A VERY DISTINCT CLEARING LINE ALONG THE TROUGH AXIS.
THE ARCTIC TROUGH ON THE EASTERN SLOPES OF THE CANADIAN ROCKIES IS
NOW BEGINNING TO TAKE SHAPE AND THE WEST COAST TROUGH IS BEGINNING
TO CLOSE OFF OVER THE NORTHERN CALIFORNIA COAST.
ENOUGH MOISTURE IS MAKING IT EASTWARD OF THE ROCKIES TO BEGIN A
FEW SPRINKLES OVER OUR WESTERN ZONES. THIS IS SOMEWHAT OF A
CHALLENGING FORECAST. FOR WHATEVER REASON...OVERNIGHT LOW
TEMPERATURES THIS MORNING ARE NOT DROPPING ANYWHERE NEAR THE
EXPECTED LEVELS. NEEDED TO MAKE SOME SIGNIFICANT
ADJUSTMENTS...WHICH IN TURN HAVE REDUCED THE EXPECTED OVERALL SNOW
FALL WITH THIS SYSTEM. DO NOT KNOW EXACTLY WHY THIS IS HAPPENING.
WINDS ARE NEAR CALM AND CLOUD COVER IS THERE...BUT IT IS NOT
SIGNIFICANTLY THICK ENOUGH TO USUALLY CAUSE NIGHT TIME
TEMPERATURES TO HOLD SO WARM REGARDLESS OF THE DAY TIME HIGH
TEMPERATURES. ANYWAY...HIGH TEMPERATURES TODAY WILL BE ABLE TO
CLIMB AGAIN OVER OUR CENTRAL AND SOUTHERN ZONES BEFORE THE COLD
FRONT SLIDES SOUTHWARD. THIS WILL LIKELY KEEP MOST OF THE EXPECTED
PRECIPITATION AS RAIN.
WITH THE ARRIVAL OF THE COLD FRONT THIS AFTERNOON...EXPECT ALL
PRECIPITATION TO CHANGE OVER TO SNOW...COINCIDENT WITH
NORTHWESTERLY WINDS INCREASING INTO THE 25G35KT RANGE. AREAS OF
BLOWING SNOW WILL BE POSSIBLE. NOT A WHOLE LOT OF CONFIDENCE IN
THIS FORECAST GIVEN THE POOR MODEL RUN TO RUN CONSISTENCY. EACH
SUCCESSIVE MODEL RUN SEEMS TO BE BACKING OFF THE QPF AND BRINGING
IN A KIND OF DRY SLOT OVER OUR CENTRAL CWA. OVERNIGHT LOW
TEMPERATURES THIS MORNING NOWHERE NEAR THE EXPECTED LEVELS.
TEMPERATURES REMAINED RELATIVELY WARM.
THE HRRR MODEL SOLUTION HAS BEEN HELPFULLY ACCURATE IN DEPICTING
THE ONSET OF THE SPRINKLES OVER OUR WESTERN AND SOUTHWESTERN ZONES
AS EVIDENCES BY RADAR REFLECTIVITIES EARLY THIS MORNING. ACCORDING
THE OPERATIONAL SHORT TERM MODEL SOLUTIONS...JUST AS SOON AS THE
PRECIPITATION GETS GOING OVER OUR NORTHWESTERN ZONES THIS
MORNING...A DRY SLOT HOLE QUICKLY OPENS UP AND CUTS OF THE
MOISTURE. I IMAGINE THERE WILL BE NEED FOR UPDATES TO KEEP UP WITH
THE UNCERTAINTY WITH THIS SYSTEM.
BY WEDNESDAY MORNING...ON THE BACKSIDE OF THIS SYSTEM...SNOW
SHOWERS WILL LINGER OVER OUR EASTERN AND NORTHEASTERN ZONES...THEN
SLIDE EASTWARD AWAY FROM OUR CWA BY WEDNESDAY EVENING WITH
DRASTICALLY CLEARING SKIES APPROACHING FROM THE WEST. THE ARCTIC
AIR WILL DROP OVERNIGHT LOWS TO NEAR ZERO DEGREES BOTH WEDNESDAY
AND THURSDAY MORNING. WINDS WILL BE ABOVE 10 KNOTS. EXPECT WIND
CHILLS TO DROP DOWN NEAR 20 DEGREES BELOW ZERO FOR A FEW OF OUR
NORTHERN AND EASTERN ZONES. A WIND CHILL ADVISORY MAY BE NEEDED.
THURSDAY WILL BE QUIET AS TEMPERATURES BEGIN TO RECOVER AND
MODERATE ABOVE NORMAL AGAIN AND CALM WIND TURN MORE OUT OF THE
WEST. BMICKELSON
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
MILD WEATHER IS EXPECTED FRIDAY AND SATURDAY. SHORTWAVE TROUGH IN
NORTHWEST FLOW ALOFT WITH WEAK COLD FRONT PASSES THROUGH THE
REGION WITH LIMITED MOISTURE. NOT SURE IF THERE WILL BE ENOUGH
MOISTURE FOR ANY PRECIPITATION. WILL MAINTAIN 10 POPS WITH NO
MENTION OF PRECIP FOR NOW.
ONE MORE SHORTWAVE RIDGE PASSES THROUGH MONTANA ON SATURDAY BEFORE
STRONG COLD FRONT DROPS SOUTH SATURDAY NIGHT AND SUNDAY. AT THIS
POINT...SATURDAY MAY BE THE LAST WARM DAY NORTHEAST MONTANA SEES
FOR A WHILE AS THE ECMWF...GEM AND TO A LESSER DEGREE THE GFS WANT
TO BREAK DOWN THE WEST COAST RIDGE THAT HAS PROVIDED MONTANA THE
UNSEASONABLY WARM WEATHER THE LAST FEW WEEKS. LIMITED MOISTURE IS
EXPECTED WITH THE INITIAL COLD FRONT. WILL MAINTAIN DRY FORECAST
FOR NOW. ARCTIC AIR MASS SETTLES INTO THE REGION SUNDAY NIGHT BUT
THE COLDEST AIR WILL STAY TO THE NORTH FOR MONDAY AND TUESDAY SO
TEMPERATURES WILL BE SOMEWHAT BELOW NORMAL. MODELS DIFFER ON
WHETHER OR NOT THERE WILL BE ENOUGH OVERRUNNING MOISTURE FOR SNOW
ON MONDAY AND TUESDAY WITH A SYSTEM TO THE SOUTH OF THE FORECAST
AREA. ARCTIC HIGH PRESSURE OVER SASKATCHEWAN MAY ALSO LIMIT PRECIP
CHANCES. WILL MENTION A SLIGHT CHANCE FOR NOW. FORRESTER
&&
.AVIATION...
VFR. MID AND HIGH LEVEL CLOUDS WILL GRADUALLY THICKEN AND LOWER
EARLY THIS MORNING. LOW CLOUDS WILL MOVE INTO THE AREA AFTER
SUNRISE WITH RAIN SHOWERS POSSIBLE THAT WILL CHANGE INTO SNOW
SHOWERS BY EARLY AFTERNOON. CEILINGS WILL HOVER NEAR THE MVFR/VFR
THRESHOLD OF 3000 FEET THIS AFTERNOON. WEST WINDS AROUND 10 KNOTS
EARLY WILL TURN NORTHWEST 15 TO 25 KNOTS WITH HIGHER GUSTS AFTER
A COLD FRONT MOVES THROUGH THE AREA THIS MORNING. THE GUSTY
NORTHWEST WINDS WILL CONTINUE TONIGHT WITH A MIX OF LOW AND MID
LEVEL CLOUDS.
&&
.CLIMATE...
MANY NEW RECORD HIGH TEMPERATURES ACROSS THE AREA WERE SET ON
MONDAY.
LOCATION NEW HIGH TEMPERATURE OLD RECORD
GLASGOW 56 54 IN 1933
ST MARIE 54 51 IN 2002
SCOBEY 4 NW 53 50 IN 2002
WOLF POINT 53 47 IN 2002
JORDAN 59 50 IN 2001
BREDETTE 50 47 IN 1953
MALTA 59 53 IN 2002
NASHUA 57 53 IN 2002
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
410 PM EST TUE JAN 10 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY AND MILD CONDITIONS TONIGHT.
A LOW PRESSURE SYSTEM WILL THEN MOVE INTO THE AREA FROM THE
SOUTHWEST, BRINGING RAIN TO THE UPPER OHIO VALLEY WEDNESDAY AND
WEDNESDAY NIGHT. SNOW SHOWERS AND MORE SEASONABLE TEMPERATURES ARE
EXPECTED AFTER THE COLD FRONT PASSAGE LATE ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A DRY WEST-NORTHWESTERLY FLOW. AT THE SURFACE, A 1018MB HIGH IS
CENTERED ACROSS WEST VIRGINIA. THIS FEATURE ALONG WITH A DEEP
LAYER OF DRY AIR ALOFT ARE ALLOWING FOR SUNNY SKIES ACROSS MUCH OF
THE AREA.
TONIGHT...THE SURFACE HIGH WILL MOVE ACROSS THE UPPER OHIO VALLEY
AND ALLOW CLEAR SKIES. CLOUD COVERAGE WILL BEGIN TO INCREASE FROM
THE SOUTHWEST TONIGHT AS CIRRUS SPILLS INTO THE AREA AHEAD OF THE
LOW ACROSS THE GULF STATES. RADIATIONAL COOLING INITIALLY TONIGHT
WILL BE COUNTERED BY THE INCREASING CLOUD COVERAGE AND WARM AIR
ADVECTION CLOSER TO DAWN ON WEDNESDAY. LOWS ARE FAIRLY CLOSE TO
MAV GUIDANCE, RANGING FROM THE UPPER 20S ALONG THE I-80 CORRIDOR
TO THE LOWER 30S ELSEWHERE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
THERE IS REASONABLE MODEL AGREEMENT THAT A 500MB CLOSED LOW WILL
MOVE FROM THE TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES
WEDNESDAY AND WEDNESDAY NIGHT THEN INTO NEW ENGLAND ON THURSDAY.
FORECAST IS CLOSEST TO A SREF/NMM-WRF/NAM4KM BLEND WITH THE CHC POPS
BEGINNING JUST AFTER 12Z FOR AREAS ALONG AND SOUTH OF THE MASON-
DIXON LINE.
THE CHALLENGE WITH THE FORECAST WILL BE HOW THE TIMING OF INITIAL
PRECIP ALIGNS WITH NEAR FREEZING TEMPS ACROSS GARRETT AND TUCKER
COUNTIES. NAM/GFS MODEL SOUNDINGS ARE SUPPORTING A FREEZING RAIN
SOUNDING WITH 3-5C WARM NOSE. THE UNCERTAINTY IS HOW FAST SURFACE
TEMPS WILL WARM. HAVE ONLY HELD ONTO A -FZRA INTO THE LATE MORNING
FOR THESE AREAS. THIS IS MENTIONED IN THE HWO WITH AROUND A TRACE
TO A FEW HUNDREDTHS OF ICE ACCUMULATION FORECASTED. AN ADVISORY
MAY BE NEEDED FOR THESE AREAS, ALTHOUGH AT THIS TIME CONFIDENCE IS
TOO LOW. OTHERWISE, WARM WEDGE OF 850MB TEMPS WARMING TO 5-6C BY
WEDNESDAY AFTERNOON ACROSS THE AREA WILL ALLOW FOR PRECIPITATION
TO BE ALL IN THE FORM OF RAIN. FOR QPF, AMOUNTS ON WEDNESDAY WILL
RANGE FROM AROUND A QUARTER OF AN INCH NORTHWEST OF PITTSBURGH TO
THREE QUARTERS OF AN INCH TO AN INCH ACROSS THE RIDGES OF PA AND
MD. WARM AIR ADVECTION THROUGHOUT THE DAY WILL ALLOW FOR TEMPS TO
WARM TO AROUND 10 DEGREES ABOVE NORMALS. HIGHS WILL RANGE FROM THE
UPPER 30S ACROSS THE EASTERN RIDGES TO NEAR 50 FOR PORTIONS OF
EASTERN OHIO AND NORTH-CENTRAL WV.
WEDNESDAY NIGHT INTO THURSDAY...NAM/ECMWF/CANADIAN ARE INDICATING
THE SURFACE LOW SPLITTING INTO A DOUBLE BARREL LOW AS IT PUSHES INTO
THE NORTHEAST. SYNOPTIC FORCING WILL SHIFT NORTHEAST OF THE AREA WITH
THE LOWS AND THE UPPER OHIO VALLEY WILL BE IN THE WARM SECTOR.
THUS, THE FORECAST IS FOR LIKELY POPS WEDNESDAY NIGHT DECREASING
TO CHANCE ON THURSDAY. A COLD FRONT ASSOCIATED WITH THE WESTERN OF
THE TWO LOWS WILL SWING ACROSS THE OHIO VALLEY ON THURSDAY AND
BEGIN TO MOVE INTO EASTERN OHIO LATE IN THE DAY. THIS WILL ALLOW
FOR ANY PRECIP TO CHANGE TO SNOW BEHIND THE FRONT. WITH THE WARM
AIR MASS STILL IN PLACE, TEMPS WILL REMAIN 10-15 DEGREES ABOVE
NORMAL.
THURSDAY NIGHT INTO FRIDAY...GFS IS FASTER THAN THE NAM WITH COLD
AIR ADVECTION AND CHANGE OVER OF PRECIP FROM RAIN TO SNOW. FORECAST IS
A BLEND OF THE TWO, PUSHING 1000-500MB 5400M THICKNESS LINE EAST OF
THE AREA AFTER 00Z AND CHANGING RAIN SHOWERS OVER TO SNOW SHOWERS
ACROSS THE AREA BY MIDNIGHT. THE INITIAL LOW THAT SHIFTED NORTHWEST
OF THE AREA WILL THEN MERGE INTO A NORTHERN STREAM UPPER LEVEL LOW
THAT WILL PUSH FROM THE GREAT LAKES INTO THE EASTERN CANADA ON
FRIDAY. THIS WILL ALLOW FOR CONTINUED STRONG COLD AIR ADVECTION.
WITH THIS FEATURE NORTH OF THE AREA, LOW-LEVEL FLOW WILL BE
WEST-SOUTHWESTERLY. COLD AIR ADVECTION SHOULD INSTIGATE SNOW
SHOWERS, ALTHOUGH EXPECT LITTLE ACCUMULATION ACROSS THE LOWLANDS.
SOME UPSLOPING WILL OCCUR ACROSS THE RIDGES THAT WOULD ALLOW FOR
ONE TO TWO INCHES OF SNOW ACCUMULATION ACROSS THERE. TEMPS WILL
BE NOTICEABLY COLDER, RANGING FROM THE UPPER TEENS ACROSS THE
EASTERN RIDGES TO THE LOWER 20S ELSEWHERE. TEMPS WILL ONLY
INCREASE A FEW DEGREES THROUGH THE DAY ON FRIDAY WITH HIGH RANGING
FROM THE LOWER 20S ACROSS THE EASTERN RIDGES TO THE MID 20S ACROSS
THE LOWLANDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LATEST ECMWF AND GFS RUNS APPEAR TO BE IN SOMEWHAT BETTER AGREEMENT
THAN IN EARLIER RUNS...SHOWING CLOSED UPPER LOW DEPARTING NEW
ENGLAND SATURDAY AND ANOTHER SHORT WAVE TROUGH CROSSING THE GREAT
LAKES REGION SATURDAY NIGHT. EXPECT COVERAGE OF SNOW SHOWERS TO
DECREASE SATURDAY...WITH CLOUD COVER ASSOCIATED WITH SECOND UPPER
TROUGH REMAINING OVER THE REGION INTO EARLY SUNDAY.
A BUILDING SURFACE RIDGE IS EXPECTED TO PROVIDE A PERIOD OF DRY
WEATHER SUNDAY AND MONDAY...WITH TEMPERATURES MODERATING FROM BELOW
NORMAL SATURDAY TO AROUND 10 DEGREES ABOVE THE NORM MONDAY.
THE NEXT APPROACHING SYSTEM WILL PUSH A COLD FRONT TOWARD THE UPPER
OHIO VALLEY TUESDAY. TEMPERATURES SHOULD REMAIN WARM ENOUGH FOR MOST
ASSOCIATED PRECIPITATION TO FALL IN THE FORM OF RAIN TUESDAY.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
SCATTERED DIURNAL CUMULUS HAVE DEVELOPED MAINLY NORTH OF A KPIT-KLBE
LINE. EXPECT THESE CLOUDS TO DISSIPATE AROUND SUNSET. WEST SURFACE
WINDS AROUND 10KT WILL BECOME LIGHT SOUTHEAST OVERNIGHT.
CONDITIONS ARE EXPECTED TO LOWER TO MVFR DURING WEDNESDAY AFTERNOON
AS RAIN SPREADS NORTHEAST AHEAD OF APPROACHING LOW PRESSURE SYSTEM
MOVING NORTHEAST FROM THE GULF STATES.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
MVFR AND AREAS OF IFR CAN BE EXPECTED WEDNESDAY NIGHT THROUGH FRIDAY
AS THE LOW MOVES NORTHEAST ACROSS THE REGION. COLDER AIR WILL PUSH
IN BEHIND THE SYSTEM BEGINNING THURSDAY NIGHT...AND PRECIPITATION
WILL CHANGE OVER TO SNOW. SCATTERED SNOW SHOWERS AND THE POTENTIAL
FOR RESTRICTIONS WILL CONTINUE THROUGH FRIDAY NIGHT.
WEAK RIDGING SHOULD PROVIDE IMPROVEMENT TO VFR BY SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
136 PM EST TUE JAN 10 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY AND MILD CONDITIONS THIS AFTERNOON
AND TONIGHT BEFORE A LOW PRESSURE SYSTEM MOVES NORTHEASTWARD,
BRINGING RAIN TO THE UPPER OHIO VALLEY WEDNESDAY AND WEDNESDAY
NIGHT. SNOW SHOWERS AND MORE SEASONABLE TEMPERATURES ARE EXPECTED
AFTER THE COLD FRONT PASSAGE LATE ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN MADE TO ADJUST
SKY GRIDS NORTHEAST OF PITTSBURGH WITH SCATTERED DIURNAL CUMULUS
DEVELOPING. OTHERWISE, NO CHANGES TO GOING FORECAST.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A DRY WEST-NORTHWESTERLY FLOW. THUS, THERE HAS BEEN ENOUGH
MOISTURE OFF OF LAKE ERIE TO ALLOW FOR SOME DIURNAL CUMULUS TO
DEVELOP NORTHEAST OF PITTSBURGH IN THIS FLOW REGIME. AT THE
SURFACE, A 1019MB HIGH IS CENTERED ACROSS WEST VIRGINIA. THIS
FEATURE ALONG WITH A DEEP LAYER OF DRY AIR ALOFT ARE ALLOWING
FOR SUNNY SKIES ACROSS MUCH OF THE AREA.
THIS AFTERNOON AND TONIGHT...THE SURFACE HIGH WILL MOVE ACROSS THE
UPPER OHIO VALLEY AND ALLOW SUNNY SKIES TODAY. WITH WEAK WARM AIR
ADVECTION AND ABUNDANT SUNSHINE, HIGHS TODAY ARE GENERALLY 1-2 DEGREES
ABOVE A MAV/MET BLEND, RANGING FROM THE LOWER 40S ACROSS THE I-80
CORRIDOR TO THE LOWER 50S IN PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL
WV. CLOUD COVERAGE WILL BEGIN TO INCREASE FROM THE SOUTHWEST
TONIGHT AS CIRRUS SPILLS INTO THE AREA AHEAD OF THE LOW ACROSS THE
GULF STATES. RADIATIONAL COOLING INITIALLY TONIGHT WILL BE COUNTERED
BY THE INCREASING CLOUD COVERAGE AND WARM AIR ADVECTION CLOSER TO
DAWN ON WEDNESDAY. LOWS ARE FAIRLY CLOSE TO MAV GUIDANCE, RANGING
FROM THE UPPER 20S ALONG THE I-80 CORRIDOR TO THE LOWER 30S
ELSEWHERE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THE AREA SHOULD REMAIN DRY EARLY WEDNESDAY AS THE LOW PRESSURE
SYSTEM MAKES ITS WAY NORTHWARD FROM LOUISIANA. ADJUSTED POP
TIMING JUST SLIGHTLY, BRINGING LIKELY POPS IN A BIT EARLIER AS
DETERMINISTIC MODELS AND SREF MEAN ARE LINING UP RELATIVELY WELL
FOR THE FIRST HALF OF THE PERIOD. GENERAL CONSENSUS IS THAT
PRECIPITATION WILL BEGIN FALLING AS RAIN AS MODEL PROFILES SUGGEST
THICKNESS VALUES WILL BE WELL WARM ENOUGH FOR RAIN DESPITE THE MID
30 TEMPERATURES AT THE SURFACE WEDNESDAY MORNING. THE ONLY CONCERN
FOR ANY FREEZING RAIN MAY COME IN SOME OF THE SHELTERED VALLEY
LOCATIONS IN THE EASTERN RIDGES EARLY WEDNESDAY, BUT IT WOULD BE
BRIEF. THIS MENTION HAS BEEN ADDED TO THE HWO.
WEDNESDAY NIGHT ANOTHER UPPER LEVEL WAVE DROPPING SOUTH OUT OF THE
NORTHERN PLAINS WILL HELP TO PUSH THE SYSTEM OVER WESTERN PA
TOWARDS THE COAST, AND ALLOW FOR THE PASSAGE OF THE LAGGING COLD
FRONT. IN ADDITION, THIS SECONDARY SYSTEM WILL BRING THE
REINFORCING SHOT OF COLD AIR NEEDED TO TRANSITION RAIN SHOWERS TO
SNOW SHOWERS LATE THURSDAY.
INFLOW OF WARMER AIR AHEAD OF THE LOW PRESSURE AND COLD FRONT WILL
MAINTAIN TEMPERATURES CLOSE TO 10 DEGREES WARMER THAN NORMAL THROUGH
THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
CONSENSUS OF ECMWF AND NAEFS MODEL OUTPUT SHOWS A COLD, CLOSED
UPPER LEVEL LOW PASSING EASTWARD THROUGH THE GREAT LAKES FRIDAY.
THIS WILL INDUCE A COLD WESTERLY LOW LEVEL FLOW ACROSS THE UPPER
OHIO VALLEY FOR FRIDAY INTO SATURDAY. AT THIS JUNCTURE, DOWN-LAKE
TRAJECTORIES ARE NOT ALL THAT FAVORABLE FOR A WIDESPREAD LAKE-
EFFECT SNOW SHOWER EVENT, BUT SHOULD FLOW SHOULD PROVIDE ENOUGH
MOISTURE AND INSTABILITY TO PROMOTE SCATTERED SNOW SHOWERS, AND
PERHAPS NUMEROUS SNOW SHOWERS AT TIMES ACROSS NORTHWESTERN PA AND
THE HIGHER MOUNTAINS.
FORECASTED TEMPERATURES, USING BLEND OF GFS MOS AND NAEFS MEDIAN
VALUES, TO BE NOTICEABLY COLDER THAN PREVIOUS DAYS, WITH
TEMPERATURES ABOUT 5 DEGREES COLDER THAN NORMAL FRIDAY AND
SATURDAY. TEMPERATURES MAY RECOVER TO NEAR NORMAL VALUES SUNDAY
AND MONDAY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
VFR WILL PREDOMINATE IN THE DRY AIRMASS OVER THE UPPER OH VALLEY
REGION. SURFACE WINDS AROUND 10KT WILL BECOME WESTERLY WITH THE
PASSAGE OF A SURFACE TROUGH.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
LOW PRESSURE MOVING OUT OF THE SOUTHERN U.S. WILL SPREAD RA AND
RESTRICTIONS OVER THE UPPER OH REGION FOR LATE WEDNESDAY AND
THURSDAY. COLD ADVECTION IN THE WAKE OF THAT SYSTEM WILL SUPPORT
RESTRICTIONS AND SHSN POTENTIAL FOR THE REMAINDER OF THE WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1127 AM EST TUE JAN 10 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY AND MILD CONDITIONS THIS AFTERNOON
AND TONIGHT BEFORE A LOW PRESSURE SYSTEM MOVES NORTHEASTWARD,
BRINGING RAIN TO THE UPPER OHIO VALLEY WEDNESDAY AND WEDNESDAY
NIGHT. SNOW SHOWERS AND MORE SEASONABLE TEMPERATURES ARE EXPECTED
AFTER THE COLD FRONT PASSAGE THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATE MORNING ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED
TO MAKE ADJUSTMENTS TO INCREASE TEMPS A FEW DEGREES TODAY AND TO
ADD A FEW HOURS OF FREEZING RAIN EARLY ON WEDNESDAY FOR TUCKER AND
GARRETT COUNTIES.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A DRY WEST-NORTHWESTERLY FLOW. CLOUD COVERAGE NORTHEAST OF
PITTSBURGH ASSOCIATED WITH THIS FLOW REGIME IS DIMINISHING. AT THE
SURFACE, A 1021MB HIGH IS CENTERED ACROSS EASTERN KENTUCKY. THIS
FEATURE ALONG WITH A DEEP LAYER OF DRY AIR ALOFT ARE ALLOWING FOR
SUNNY SKIES ACROSS MUCH OF THE AREA.
THIS AFTERNOON AND TONIGHT...THE SURFACE HIGH WILL MOVE ACROSS THE
UPPER OHIO VALLEY AND ALLOW SUNNY SKIES TODAY. WITH WEAK WARM AIR
ADVECTION AND ABUNDANT SUNSHINE, HIGHS TODAY ARE GENERALLY 1-2 DEGREES
ABOVE A MAV/MET BLEND, RANGING FROM THE LOWER 40S ACROSS THE I-80
CORRIDOR TO THE LOWER 50S IN PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL
WV. CLOUD COVERAGE WILL BEGIN TO INCREASE FROM THE SOUTHWEST
TONIGHT AS CIRRUS SPILLS INTO THE AREA AHEAD OF THE LOW ACROSS THE
GULF STATES. RADIATIONAL COOLING INITIALLY TONIGHT WILL BE COUNTERED
BY THE INCREASING CLOUD COVERAGE AND WARM AIR ADVECTION CLOSER TO
DAWN ON WEDNESDAY. LOWS ARE FAIRLY CLOSE TO MAV GUIDANCE, RANGING
FROM THE UPPER 20S ALONG THE I-80 CORRIDOR TO THE LOWER 30S
ELSEWHERE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THE AREA SHOULD REMAIN DRY EARLY WEDNESDAY AS THE LOW PRESSURE
SYSTEM MAKES ITS WAY NORTHWARD FROM LOUISIANA. ADJUSTED POP
TIMING JUST SLIGHTLY, BRINGING LIKELY POPS IN A BIT EARLIER AS
DETERMINISTIC MODELS AND SREF MEAN ARE LINING UP RELATIVELY WELL
FOR THE FIRST HALF OF THE PERIOD. GENERAL CONSENSUS IS THAT
PRECIPITATION WILL BEGIN FALLING AS RAIN AS MODEL PROFILES SUGGEST
THICKNESS VALUES WILL BE WELL WARM ENOUGH FOR RAIN DESPITE THE MID
30 TEMPERATURES AT THE SURFACE WEDNESDAY MORNING. THE ONLY CONCERN
FOR ANY FREEZING RAIN MAY COME IN SOME OF THE SHELTERED VALLEY
LOCATIONS IN THE EASTERN RIDGES EARLY WEDNESDAY, BUT IT WOULD BE
BRIEF. THIS MENTION HAS BEEN ADDED TO THE HWO.
WEDNESDAY NIGHT ANOTHER UPPER LEVEL WAVE DROPPING SOUTH OUT OF THE
NORTHERN PLAINS WILL HELP TO PUSH THE SYSTEM OVER WESTERN PA
TOWARDS THE COAST, AND ALLOW FOR THE PASSAGE OF THE LAGGING COLD
FRONT. IN ADDITION, THIS SECONDARY SYSTEM WILL BRING THE
REINFORCING SHOT OF COLD AIR NEEDED TO TRANSITION RAIN SHOWERS TO
SNOW SHOWERS LATE THURSDAY.
INFLOW OF WARMER AIR AHEAD OF THE LOW PRESSURE AND COLD FRONT WILL
MAINTAIN TEMPERATURES CLOSE TO 10 DEGREES WARMER THAN NORMAL THROUGH
THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONSENSUS OF ECMWF AND NAEFS MODEL OUTPUT SHOWS A COLD, CLOSED
UPPER LEVEL LOW PASSING EASTWARD THROUGH THE GREAT LAKES FRIDAY.
THIS WILL INDUCE A COLD WESTERLY LOW LEVEL FLOW ACROSS THE UPPER
OHIO VALLEY FOR FRIDAY INTO SATURDAY. AT THIS JUNCTURE, DOWN-LAKE
TRAJECTORIES ARE NOT ALL THAT FAVORABLE FOR A WIDESPREAD LAKE-
EFFECT SNOW SHOWER EVENT, BUT SHOULD FLOW SHOULD PROVIDE ENOUGH
MOISTURE AND INSTABILITY TO PROMOTE SCATTERED SNOW SHOWERS, AND
PERHAPS NUMEROUS SNOW SHOWERS AT TIMES ACROSS NORTHWESTERN PA AND
THE HIGHER MOUNTAINS.
FORECASTED TEMPERATURES, USING BLEND OF GFS MOS AND NAEFS MEDIAN
VALUES, TO BE NOTICEABLY COLDER THAN PREVIOUS DAYS, WITH
TEMPERATURES ABOUT 5 DEGREES COLDER THAN NORMAL FRIDAY AND
SATURDAY. TEMPERATURES MAY RECOVER TO NEAR NORMAL VALUES SUNDAY
AND MONDAY.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
VFR WILL PREDOMINATE IN THE DRY AIRMASS OVER THE UPPER OH VALLEY
REGION. SURFACE WINDS AROUND 10KT WILL BECOME WESTERLY WITH THE
PASSAGE OF A SURFACE TROUGH.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
LOW PRESSURE MOVING OUT OF THE SOUTHERN U.S. WILL SPREAD RA AND
RESTRICTIONS OVER THE UPPER OH REGION FOR LATE WEDNESDAY AND
THURSDAY. COLD ADVECTION IN THE WAKE OF THAT SYSTEM WILL SUPPORT
RESTRICTIONS AND SHSN POTENTIAL FOR THE REMAINDER OF THE WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GLASGOW MT
302 PM MST TUE JAN 10 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
ARCTIC COLD FRONT HAS PASSED BY A LINE FROM PLENTYWOOD THROUGH
GLASGOW THIS AFTERNOON AND IS PROGRESSING SOUTHEASTWARD. AREAS
AHEAD OF THE FRONT HAVE ALL RAIN WHILE AREAS BEHIND THE FRONT HAVE
ALL SNOW. MODEL BLEND GIVES A HALF INCH TO AN INCH AND A HALF OF
TOTAL SNOW FALL ACCUMULATION BEHIND THE FRONT. PRECIPITATION
WILL BEGIN TO DECLINE BY MIDNIGHT
WINDS BEHIND THE FRONT ARE CURRENTLY NORTHWESTERLY AT 15 TO 20 MPH
AND WILL INCREASE TO 20 TO 25 MPH OVER NIGHT. COLD ADVECTION
BEHIND THE FRONT WILL DROP TEMPERATURES STEADILY ALL NIGHT.
TEMPERATURE WILL REACH NEAR 0 ALONG THE INTERNATIONAL BORDER BY
MORNING. THIS WILL COMBINE WITH WIND TO PRODUCE BITTER COLD WIND
CHILL DOWN TO 22 BELOW FOR AREAS NEAR THE INTERNATIONAL BORDER.
BLOWING SNOW AND REDUCED VISIBILITY IS A LIKELY IMPACT FROM THE
SNOW AND WIND COMBINATION TONIGHT...HOWEVER...RELATIVELY LIGHT
SNOW SEEN SO FAR SHOULD LEAD TO VISIBILITIES GENERALLY A HALF MILE
OR BETTER. SNOW AMOUNTS SHOULD ALSO DECLINE AFTER DARK. SHOULD
OBSERVATIONS SHOW WORSE CONDITIONS...AN ADVISORY MAY BE NEEDED.
COLD FRONT THAT PASSED THROUGH GLASGOW THIS AFTERNOON IS RELATED
TO A MIDLEVEL TROUGH THAT IS DIGGING SOUTHEASTWARD THROUGH IDAHO
AND EASTERN MONTANA. TEMPERATURES WILL BE BACK DOWN TO NEAR
SEASONAL NORMAL WEDNESDAY AND THURSDAY BEHIND THE FRONT. HOW COLD
IT WILL ACTUALLY GET WILL DEPEND ON HOW MUCH SNOW ACCUMULATION
WILL OCCUR AND HOW MUCH CLOUD COVER. THURSDAY MORNING IS EXPECTED
TO THE BE COLDEST TIME WITH LOWS DOWN BELOW ZERO IN MOST PLACES.
MARTIN
PREVIOUS SHORT TERM DISCUSSION... WATER VAPOR IMAGERY AND 500 MB
HEIGHT FIELD SHOWING A REX BLOCK UPPER LEVEL FLOW PATTERN ACROSS
THE CONUS. THE CUT-OFF UPPER LOW CENTER IS SPINNING OVER EASTERN
TEXAS AND SETTING OFF THUNDERSTORMS OVER THE RED RIVER REGION AND
THE NORTHERN GULF SHORES. AN ELONGATED BUT RELATIVELY CALM UPPER
TROUGH IS MOVING OVER NEW ENGLAND. UPPER LEVEL ZONAL FLOW IS IN
PLACE OVER THE NORTHERN HIGH PLAINS...NORTH OF THE CUT-OFF LOW.
SHORT WAVE RIDGING FAVORS THE FAR SOUTHWESTERN CONUS. A NEW UPPER
LEVEL TROUGH HAS MOVED ON SHORE OVER THE PACIFIC NORTHWEST.
THIS APPROACHING WESTERN TROUGH IS PUSHING A FAIR AMOUNT OF
PACIFIC MOISTURE ALONG AND AHEAD OF IT OVER THE NORTHERN ROCKIES.
IT ALSO SHOWS A VERY DISTINCT CLEARING LINE ALONG THE TROUGH AXIS.
THE ARCTIC TROUGH ON THE EASTERN SLOPES OF THE CANADIAN ROCKIES IS
NOW BEGINNING TO TAKE SHAPE AND THE WEST COAST TROUGH IS BEGINNING
TO CLOSE OFF OVER THE NORTHERN CALIFORNIA COAST.
ENOUGH MOISTURE IS MAKING IT EASTWARD OF THE ROCKIES TO BEGIN A
FEW SPRINKLES OVER OUR WESTERN ZONES. THIS IS SOMEWHAT OF A
CHALLENGING FORECAST. FOR WHATEVER REASON...OVERNIGHT LOW
TEMPERATURES THIS MORNING ARE NOT DROPPING ANYWHERE NEAR THE
EXPECTED LEVELS. NEEDED TO MAKE SOME SIGNIFICANT
ADJUSTMENTS...WHICH IN TURN HAVE REDUCED THE EXPECTED OVERALL SNOW
FALL WITH THIS SYSTEM. DO NOT KNOW EXACTLY WHY THIS IS HAPPENING.
WINDS ARE NEAR CALM AND CLOUD COVER IS THERE...BUT IT IS NOT
SIGNIFICANTLY THICK ENOUGH TO USUALLY CAUSE NIGHT TIME
TEMPERATURES TO HOLD SO WARM REGARDLESS OF THE DAY TIME HIGH
TEMPERATURES. ANYWAY...HIGH TEMPERATURES TODAY WILL BE ABLE TO
CLIMB AGAIN OVER OUR CENTRAL AND SOUTHERN ZONES BEFORE THE COLD
FRONT SLIDES SOUTHWARD. THIS WILL LIKELY KEEP MOST OF THE EXPECTED
PRECIPITATION AS RAIN.
WITH THE ARRIVAL OF THE COLD FRONT THIS AFTERNOON...EXPECT ALL
PRECIPITATION TO CHANGE OVER TO SNOW...COINCIDENT WITH
NORTHWESTERLY WINDS INCREASING INTO THE 25G35KT RANGE. AREAS OF
BLOWING SNOW WILL BE POSSIBLE. NOT A WHOLE LOT OF CONFIDENCE IN
THIS FORECAST GIVEN THE POOR MODEL RUN TO RUN CONSISTENCY. EACH
SUCCESSIVE MODEL RUN SEEMS TO BE BACKING OFF THE QPF AND BRINGING
IN A KIND OF DRY SLOT OVER OUR CENTRAL CWA. OVERNIGHT LOW
TEMPERATURES THIS MORNING NOWHERE NEAR THE EXPECTED LEVELS.
TEMPERATURES REMAINED RELATIVELY WARM.
THE HRRR MODEL SOLUTION HAS BEEN HELPFULLY ACCURATE IN DEPICTING
THE ONSET OF THE SPRINKLES OVER OUR WESTERN AND SOUTHWESTERN ZONES
AS EVIDENCES BY RADAR REFLECTIVITIES EARLY THIS MORNING. ACCORDING
THE OPERATIONAL SHORT TERM MODEL SOLUTIONS...JUST AS SOON AS THE
PRECIPITATION GETS GOING OVER OUR NORTHWESTERN ZONES THIS
MORNING...A DRY SLOT HOLE QUICKLY OPENS UP AND CUTS OF THE
MOISTURE. I IMAGINE THERE WILL BE NEED FOR UPDATES TO KEEP UP WITH
THE UNCERTAINTY WITH THIS SYSTEM.
BY WEDNESDAY MORNING...ON THE BACKSIDE OF THIS SYSTEM...SNOW
SHOWERS WILL LINGER OVER OUR EASTERN AND NORTHEASTERN ZONES...THEN
SLIDE EASTWARD AWAY FROM OUR CWA BY WEDNESDAY EVENING WITH
DRASTICALLY CLEARING SKIES APPROACHING FROM THE WEST. THE ARCTIC
AIR WILL DROP OVERNIGHT LOWS TO NEAR ZERO DEGREES BOTH WEDNESDAY
AND THURSDAY MORNING. WINDS WILL BE ABOVE 10 KNOTS. EXPECT WIND
CHILLS TO DROP DOWN NEAR 20 DEGREES BELOW ZERO FOR A FEW OF OUR
NORTHERN AND EASTERN ZONES. A WIND CHILL ADVISORY MAY BE NEEDED.
THURSDAY WILL BE QUIET AS TEMPERATURES BEGIN TO RECOVER AND
MODERATE ABOVE NORMAL AGAIN AND CALM WIND TURN MORE OUT OF THE
WEST. BMICKELSON
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
HIGH PRESSURE OFF THE COAST OF CALIFORNIA CONTINUES TO ANCHOR AN
UPPER LEVEL RIDGE OVER THE WEST FRIDAY AND SATURDAY. THIS WILL
MAINTAIN MILD CONDITIONS WITH TEMPERATURES AROUND 10*F TO 15*F
ABOVE NORMAL THROUGH SUNDAY. THE NEXT UPPER LEVEL TROUGH AND
ASSOCIATED ARCTIC COLD FRONT DROP INTO WESTERN CANADA THIS
WEEKEND. TIMING DIFFERS BETWEEN THE GFS AND EC. THE MON 00Z EC
BRINGS THE FRONT ACROSS THE INTERNATIONAL BORDER SATURDAY NIGHT.
THE 12Z GFS IS SLOWER...BRINGING THE FRONT OVER THE BORDER SUNDAY
NIGHT. HOWEVER THE 12Z EC CAME IN MUCH MORE IN LINE WITH THE GFS.
A MODERATE AMOUNT OF PACIFIC MOISTURE OVERRUNNING THE FRONT WILL
PRODUCE SNOW OVER MONTANA. NORTHEAST MONTANA MIGHT BE DRY
SLOTTED...EXCEPT FOR THE SOUTHWEST AREAS. QPF WILL NOT BE
SUBSTANTIAL...SO NO MORE THAN AN INCH OR TWO IS EXPECTED. THE MAIN
STORY WILL BE THE DROPPING TEMPERATURES. A POLAR AIR MASS
CURRENTLY HOVERING OVER THE ARCTIC OCEAN NORTH OF ALASKA SLIDES
SOUTH OVER CANADA. BOTH THE GFS AND EC HAVE 850MB TEMPERATURES
NEAR PLENTYWOOD AT AROUND -24*C BY 00Z TUESDAY. THEREFORE HIGHS
EARLY NEXT WEEK WILL RANGE IN THE SINGLE DIGITS AND LOWER TEENS.
A FEW MINOR GRID EDITS WERE MADE TO POPS FOR EARLY NEXT WEEK.
TEMPERATURES WERE ALSO LOWERED TO CONTINUE THE TREND TO COLDER
AIR. SCT
PREVIOUS DISCUSSION...
MILD WEATHER IS EXPECTED FRIDAY AND SATURDAY. SHORTWAVE TROUGH IN
NORTHWEST FLOW ALOFT WITH WEAK COLD FRONT PASSES THROUGH THE
REGION WITH LIMITED MOISTURE. NOT SURE IF THERE WILL BE ENOUGH
MOISTURE FOR ANY PRECIPITATION. WILL MAINTAIN 10 POPS WITH NO
MENTION OF PRECIP FOR NOW.
ONE MORE SHORTWAVE RIDGE PASSES THROUGH MONTANA ON SATURDAY BEFORE
STRONG COLD FRONT DROPS SOUTH SATURDAY NIGHT AND SUNDAY. AT THIS
POINT...SATURDAY MAY BE THE LAST WARM DAY NORTHEAST MONTANA SEES
FOR A WHILE AS THE ECMWF...GEM AND TO A LESSER DEGREE THE GFS WANT
TO BREAK DOWN THE WEST COAST RIDGE THAT HAS PROVIDED MONTANA THE
UNSEASONABLY WARM WEATHER THE LAST FEW WEEKS. LIMITED MOISTURE IS
EXPECTED WITH THE INITIAL COLD FRONT. WILL MAINTAIN DRY FORECAST
FOR NOW. ARCTIC AIRMASS SETTLES INTO THE REGION SUNDAY NIGHT BUT
THE COLDEST AIR WILL STAY TO THE NORTH FOR MONDAY AND TUESDAY SO
TEMPERATURES WILL BE SOMEWHAT BELOW NORMAL. MODELS DIFFER ON
WHETHER OR NOT THERE WILL BE ENOUGH OVERRUNNING MOISTURE FOR SNOW
ON MONDAY AND TUESDAY WITH A SYSTEM TO THE SOUTH OF THE FORECAST
AREA. ARCTIC HIGH PRESSURE OVER SASKATCHEWAN MAY ALSO LIMIT PRECIP
CHANCES. WILL MENTION A SLIGHT CHANCE FOR NOW. FORRESTER
&&
.AVIATION...
AN ARCTIC COLD FRONT DROPPING SOUTH OVER THE AREA BROUGHT RAIN
THIS MORNING THAT TRANSITIONED OVER TO SNOW THIS AFTERNOON. THESE
SNOW SHOWERS SHOULD TAPER OFF BY EVENING. THEREFORE EXPECT
PERIODS OF IFR CEILINGS AND VISIBILITIES. STRONG NORTHERLY WINDS
OF 15 TO 25 KTS BEHIND THE FRONT ARE EXPECTED TO REMAIN STRONG
THROUGHOUT THE NIGHT AS SKIES CLEAR FROM THE NORTH. WINDS ON
WEDNESDAY WILL CONTINUE STRONG AT AROUND 20KTS. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 10 AM MST
THURSDAY FOR DANIELS...SHERIDAN...NORTHERN VALLEY.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
934 AM MST TUE JAN 10 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
SCATTERED AREAS OF LIGHT RAIN OVER ABOUT THE NORTHWESTERN TWO
THIRDS OF THE CWA THIS MORNING SHOULD REMAIN RAIN UNTIL THE
PASSAGE OF A COLD FRONT THIS AFTERNOON. COLD FRONT...CURRENTLY IN
CANADA...WILL ENTER NORTHWESTERN SECTIONS OF THE AREA AFTER NOON
AND PUSH THROUGH THE AREA BY NIGHTFALL. PRECIPITATION BEHIND THE
FRONT WILL BE SNOW...BUT WILL BE LIGHTER THAN THE RAIN AHEAD OF
THE FRONT. WINDS WILL ALSO BE BRISK AND FROM THE NORTH BEHIND THE FRONT.
SNOW ACCUMULATIONS BEHIND THE FRONT WILL NOT BE HEAVY...AND WILL
RANGE FROM ZERO TO 1 INCH. MARTIN.
PREVIOUS SHORT TERM DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWING A REX BLOCK
UPPER LEVEL FLOW PATTERN ACROSS THE CONUS. THE CUT-OFF UPPER LOW
CENTER IS SPINNING OVER EASTERN TEXAS AND SETTING OFF
THUNDERSTORMS OVER THE RED RIVER REGION AND THE NORTHERN GULF
SHORES. AN ELONGATED BUT RELATIVELY CALM UPPER TROUGH IS MOVING
OVER NEW ENGLAND. UPPER LEVEL ZONAL FLOW IS IN PLACE OVER THE
NORTHERN HIGH PLAINS...NORTH OF THE CUT-OFF LOW. SHORT WAVE
RIDGING FAVORS THE FAR SOUTHWESTERN CONUS. A NEW UPPER LEVEL TROUGH
HAS MOVED ON SHORE OVER THE PACIFIC NORTHWEST.
THIS APPROACHING WESTERN TROUGH IS PUSHING A FAIR AMOUNT OF
PACIFIC MOISTURE ALONG AND AHEAD OF IT OVER THE NORTHERN ROCKIES.
IT ALSO SHOWS A VERY DISTINCT CLEARING LINE ALONG THE TROUGH AXIS.
THE ARCTIC TROUGH ON THE EASTERN SLOPES OF THE CANADIAN ROCKIES IS
NOW BEGINNING TO TAKE SHAPE AND THE WEST COAST TROUGH IS BEGINNING
TO CLOSE OFF OVER THE NORTHERN CALIFORNIA COAST.
ENOUGH MOISTURE IS MAKING IT EASTWARD OF THE ROCKIES TO BEGIN A
FEW SPRINKLES OVER OUR WESTERN ZONES. THIS IS SOMEWHAT OF A
CHALLENGING FORECAST. FOR WHATEVER REASON...OVERNIGHT LOW
TEMPERATURES THIS MORNING ARE NOT DROPPING ANYWHERE NEAR THE
EXPECTED LEVELS. NEEDED TO MAKE SOME SIGNIFICANT
ADJUSTMENTS...WHICH IN TURN HAVE REDUCED THE EXPECTED OVERALL SNOW
FALL WITH THIS SYSTEM. DO NOT KNOW EXACTLY WHY THIS IS HAPPENING.
WINDS ARE NEAR CALM AND CLOUD COVER IS THERE...BUT IT IS NOT
SIGNIFICANTLY THICK ENOUGH TO USUALLY CAUSE NIGHT TIME
TEMPERATURES TO HOLD SO WARM REGARDLESS OF THE DAY TIME HIGH
TEMPERATURES. ANYWAY...HIGH TEMPERATURES TODAY WILL BE ABLE TO
CLIMB AGAIN OVER OUR CENTRAL AND SOUTHERN ZONES BEFORE THE COLD
FRONT SLIDES SOUTHWARD. THIS WILL LIKELY KEEP MOST OF THE EXPECTED
PRECIPITATION AS RAIN.
WITH THE ARRIVAL OF THE COLD FRONT THIS AFTERNOON...EXPECT ALL
PRECIPITATION TO CHANGE OVER TO SNOW...COINCIDENT WITH
NORTHWESTERLY WINDS INCREASING INTO THE 25G35KT RANGE. AREAS OF
BLOWING SNOW WILL BE POSSIBLE. NOT A WHOLE LOT OF CONFIDENCE IN
THIS FORECAST GIVEN THE POOR MODEL RUN TO RUN CONSISTENCY. EACH
SUCCESSIVE MODEL RUN SEEMS TO BE BACKING OFF THE QPF AND BRINGING
IN A KIND OF DRY SLOT OVER OUR CENTRAL CWA. OVERNIGHT LOW
TEMPERATURES THIS MORNING NOWHERE NEAR THE EXPECTED LEVELS.
TEMPERATURES REMAINED RELATIVELY WARM.
THE HRRR MODEL SOLUTION HAS BEEN HELPFULLY ACCURATE IN DEPICTING
THE ONSET OF THE SPRINKLES OVER OUR WESTERN AND SOUTHWESTERN ZONES
AS EVIDENCES BY RADAR REFLECTIVITIES EARLY THIS MORNING. ACCORDING
THE OPERATIONAL SHORT TERM MODEL SOLUTIONS...JUST AS SOON AS THE
PRECIPITATION GETS GOING OVER OUR NORTHWESTERN ZONES THIS
MORNING...A DRY SLOT HOLE QUICKLY OPENS UP AND CUTS OF THE
MOISTURE. I IMAGINE THERE WILL BE NEED FOR UPDATES TO KEEP UP WITH
THE UNCERTAINTY WITH THIS SYSTEM.
BY WEDNESDAY MORNING...ON THE BACKSIDE OF THIS SYSTEM...SNOW
SHOWERS WILL LINGER OVER OUR EASTERN AND NORTHEASTERN ZONES...THEN
SLIDE EASTWARD AWAY FROM OUR CWA BY WEDNESDAY EVENING WITH
DRASTICALLY CLEARING SKIES APPROACHING FROM THE WEST. THE ARCTIC
AIR WILL DROP OVERNIGHT LOWS TO NEAR ZERO DEGREES BOTH WEDNESDAY
AND THURSDAY MORNING. WINDS WILL BE ABOVE 10 KNOTS. EXPECT WIND
CHILLS TO DROP DOWN NEAR 20 DEGREES BELOW ZERO FOR A FEW OF OUR
NORTHERN AND EASTERN ZONES. A WIND CHILL ADVISORY MAY BE NEEDED.
THURSDAY WILL BE QUIET AS TEMPERATURES BEGIN TO RECOVER AND
MODERATE ABOVE NORMAL AGAIN AND CALM WIND TURN MORE OUT OF THE
WEST. BMICKELSON
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
MILD WEATHER IS EXPECTED FRIDAY AND SATURDAY. SHORTWAVE TROUGH IN
NORTHWEST FLOW ALOFT WITH WEAK COLD FRONT PASSES THROUGH THE
REGION WITH LIMITED MOISTURE. NOT SURE IF THERE WILL BE ENOUGH
MOISTURE FOR ANY PRECIPITATION. WILL MAINTAIN 10 POPS WITH NO
MENTION OF PRECIP FOR NOW.
ONE MORE SHORTWAVE RIDGE PASSES THROUGH MONTANA ON SATURDAY BEFORE
STRONG COLD FRONT DROPS SOUTH SATURDAY NIGHT AND SUNDAY. AT THIS
POINT...SATURDAY MAY BE THE LAST WARM DAY NORTHEAST MONTANA SEES
FOR A WHILE AS THE ECMWF...GEM AND TO A LESSER DEGREE THE GFS WANT
TO BREAK DOWN THE WEST COAST RIDGE THAT HAS PROVIDED MONTANA THE
UNSEASONABLY WARM WEATHER THE LAST FEW WEEKS. LIMITED MOISTURE IS
EXPECTED WITH THE INITIAL COLD FRONT. WILL MAINTAIN DRY FORECAST
FOR NOW. ARCTIC AIRMASS SETTLES INTO THE REGION SUNDAY NIGHT BUT
THE COLDEST AIR WILL STAY TO THE NORTH FOR MONDAY AND TUESDAY SO
TEMPERATURES WILL BE SOMEWHAT BELOW NORMAL. MODELS DIFFER ON
WHETHER OR NOT THERE WILL BE ENOUGH OVERRUNNING MOISTURE FOR SNOW
ON MONDAY AND TUESDAY WITH A SYSTEM TO THE SOUTH OF THE FORECAST
AREA. ARCTIC HIGH PRESSURE OVER SASKATCHEWAN MAY ALSO LIMIT PRECIP
CHANCES. WILL MENTION A SLIGHT CHANCE FOR NOW. FORRESTER
&&
.AVIATION...
VFR. MID AND HIGH LEVEL CLOUDS WILL GRADUALLY THICKEN AND LOWER
EARLY THIS MORNING. LOW CLOUDS WILL MOVE INTO THE AREA AFTER
SUNRISE WITH RAIN SHOWERS POSSIBLE THAT WILL CHANGE INTO SNOW
SHOWERS BY EARLY AFTERNOON. CEILINGS WILL HOVER NEAR THE MVFR/VFR
THRESHOLD OF 3000 FEET THIS AFTERNOON. WEST WINDS AROUND 10 KNOTS
EARLY WILL TURN NORTHWEST 15 TO 25 KNOTS WITH HIGHER GUSTS AFTER
A COLD FRONT MOVES THROUGH THE AREA THIS MORNING. THE GUSTY
NORTHWEST WINDS WILL CONTINUE TONIGHT WITH A MIX OF LOW AND MID
LEVEL CLOUDS.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW