Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/29/14
AREA FORECAST DISCUSSION
NWS EUREKA CA
331 PM PST SUN DEC 28 2014
.SYNOPSIS...A REINFORCING COLD FRONT WILL BRING ANOTHER CHANCE
OF LIGHT SHOWERS NORTH OF THE CAPE ON MONDAY...FOLLOWED BY MOSTLY
DRY AND COLD CONDITIONS FOR MUCH OF THE COMING WEEK. EASTERLY
WINDS MAY BE QUITE GUSTY TUESDAY THROUGH WEDNESDAY AS A LOW
PRESSURE SYSTEM DEEPENS OVER CENTRAL CALIFORNIA.
&&
.SHORT TERM...(THROUGH THURSDAY NIGHT) A COLD FRONT HAS MOVED SOUTH
OF NORTHWEST CALIFORNIA LEAVING NORTHERLY FLOW OVER THE REGION AND
CLEARING SKIES. LOW TEMPERATURES TONIGHT WILL BE SEVERAL DEGREES
LOWER THAN LAST NIGHT WITH TEMPERATURES FALLING BACK INTO THE 30S
FOR MOST AREAS AND 20S IN THE INTERIOR.
ANOTHER MUCH STRONGER COLD FRONT WILL DIVE DOWN THE WEST COAST ON
MONDAY AS A DEEP WESTERN US TROUGH DEVELOPS OVER THE INTER-MOUNTAIN
WEST IN RESPONSE TO A BUILDING RIDGE OFF THE WEST COAST. A FEW
SHOWERS WILL BE POSSIBLE IN DEL NORTE AND COASTAL HUMBOLDT WITH AND
JUST BEHIND THE FRONT. SNOW LEVELS WILL RAPIDLY FALL TO NEAR 2000
FEET WHICH COULD ALLOW SOME NEAR COAST RIDGES TO SEE SOME
FLAKES...BUT VERY LITTLE IF ANY ACCUMULATION IS EXPECTED.
THE COLD AIR MASS BEHIND THIS FRONT WILL BE SIGNIFICANTLY COLDER
RESULTING IN LOWS FALLING INTO THE 20S AND TEENS ACROSS THE INTERIOR
AND NEAR OR POSSIBLY BELOW FREEZING AT THE COAST BY WEDNESDAY
MORNING AND THEN AGAIN THURSDAY MORNING. THE PRIMARILY MITIGATING
FACTOR TO COLD TEMPERATURES WILL BE A STRONG OFFSHORE PRESSURE
GRADIENT LATE MONDAY NIGHT THROUGH WEDNESDAY BEHIND THE FRONT AS AN
UPPER LOW ATTEMPTS TO CUT OFF OVER CENTRAL CALIFORNIA. THIS WILL
LIKELY ALLOW MIXING HOLDING TEMPERATURES UP A FEW DEGREES ABOVE
MODEL GUIDANCE...PARTICULARLY TUESDAY MORNING.
THIS STRONG PRESSURE GRADIENT WILL ALSO RESULT IN STRONG EASTERLY
WINDS ACROSS THE REGION. THE ENSEMBLES INDICATE THIS WILL BE A
HIGHLY ANOMALOUS EVENT WITH 700 MB EAST-NORTHEAST WINDS BETWEEN 40
AND 60 KT MOVING OVER THE REGION TUESDAY NIGHT AND EARLY WEDNESDAY.
WITH A VERY COLD AIR MASS IN PLACE AND EXCELLENT MIXING THERE IS
POTENTIAL FOR THESE WINDS TO MIX DOWN TO THE RIDGE TOPS. THUS WINDS
HAVE BEEN RAMPED UP WITH THIS FORECAST IN THE MOUNTAINS ACROSS THE
ENTIRE REGION. THE TIGHTEST PRESSURE GRADIENT WILL LIKELY BE OVER
MENDOCINO COUNTY AND WIND ADVISORY/WATCH PRODUCTS MAY BE REQUIRED
FOR TUESDAY THROUGH WEDNESDAY. WINDS WILL NOT BE AS STRONG ON THE
VALLEY FLOORS BUT SOME GUSTY CONDITIONS ARE EXPECTED. RPA
.LONG TERM...(FRIDAY THROUGH SUNDAY)...MODELS BEGIN TO DIVERGE A
LITTLE LATE IN THE WEEK REGARDING THE EASTWARD MOVEMENT AND
INTENSITY OF THE RIDGE OFF THE WEST COAST AND THE STRENGTH OF AN
UPPER LEVEL TROUGH THAT MOVES INTO THE PACIFIC NORTHWEST. THE GFS
CONTINUES TO INDICATE A WEAK FRONT MAY APPROACH THE NORTHERN
REACHES OF NORTHWEST CALIFORNIA BRINGING A CHANCE FOR RAIN TO DEL
NORTE COUNTY BY LATE IN THE WEEKEND OR EARLY NEXT WEEK WHILE THE
ECMWF HAS DROPPED THIS FEATURE AND NOW INDICATES RIDGING JUST OFF
THE WEST COAST. FOR NOW HAVE CONTINUED A SLIGHT CHANCE OF
PRECIPITATION FOR THE NORTHERN PORTION OF THE AREA WITH VERY LOW
CONFIDENCE IN THE RESULTING WEATHER FOR SUNDAY. TRN/RPA
&&
.AVIATION...AFTERNOON SCT VFR CUMULUS CLOUDS ARE THE ONLY CLOUDS
LEFT FROM A FRONT DISSIPATING OFF OF THE CAPE MENDOCINO COAST.
EXPECT THESE CLOUDS TO DECREASE THROUGH THE NIGHT AND DEVELOPMENT OF
PATCHY VALLEY FOG WILL RESULT IN MVFR TO IFR CONDITIONS ACROSS
INTERIOR VALLEYS AFTER MIDNIGHT. VALLEY FOG WILL DISSIPATE BY NOON.
ANOTHER WEAK FRONT MOVING DOWN FROM OREGON WILL BRING MVFR CIGS AND
LIGHT RAIN MONDAY AFTERNOON NORTH OF CAPE MENDO. DEAN
&&
.MARINE...NORTHERLY WINDS WILL SLOWLY INCREASE THROUGH THURSDAY AS A
THERMAL TROUGH OVER CALIFORNIA AND BUILDING HIGH PRESSURE OFFSHORE
STRENGTHEN THE PRESSURE GRADIENT. FRESH WINDS AND STEEPENING SEAS
WILL BEGIN TO DEVELOP SOUTH OF CAPE MENDOCINO TONIGHT AND SPREAD
NORTHWARD BY MONDAY AFTERNOON. WINDS IN THE OUTER WATERS STAY JUST
BELOW SMALL CRAFT ADVISORY UNTIL MONDAY NIGHT. THE HRRR DID SHOW
GUSTS ABOVE CRITERIA SOONER FOR ZONE 475 BUT IT WAS THE OUTLIER.
WINDS STAY BELOW ADVISORY CRITERIA IN THE INNER WATERS. WINDS AND
SEAS WILL EASE AGAIN LATE IN THE WEEK AS A DEEP, COLD UPPER LEVEL
TROUGH DIVES OVER CALIFORNIA AND HELPS BREAK DOWN THE PRESSURE
GRADIENT BY WEAKENING THE THERMAL TROUGH. KMLTRN
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1156 PM MST FRI DEC 26 2014
.UPDATE...
ISSUED AT 1153 PM MST FRI DEC 26 2014
WILL ALLOW THE REMAINING WINTER HIGHLIGHTS TO EXPIRE AT MIDNIGHT.
LATEST RAP AND ARW MODELS SHOW LIGHT SNOW CONTINUING TO DECREASE IN
AREAL COVERAGE OVERNIGHT. KJGX RADAR RETURNS WERE ALSO SHRINKING.
EXPECT ANY ADDITIONAL SNOW ACCUMULATIONS TO BE GENERALLY LESS
THAN AN INCH.
THE NEXT STORM EXPECTED TO AFFECT OUR AREA IN THE SUNDAY AND MONDAY
WAS CURRENTLY MOVING DOWN THE ALASKAN PANHANDLE PER SATELLITE
IMAGES.
UPDATE ISSUED AT 937 PM MST FRI DEC 26 2014
THIS LATEST STORM CONTINUES TO WIND DOWN THIS EVENING WITH THE
UPPER TROUGH AXIS FROM AZ ACROSS CO TO THE NORTHERN PLAINS.
SATELLITE WATER VAPOR IMAGES INDICATED A SMALL JET MAX NEAR THE
ID/NV/UT TRIPLE POINT...WHICH MAY KEEP THE BASE OF THE TROUGH
HANGING BACK OVER THE DESERT SOUTHWEST UNTIL MORNING. LIGHT SNOW WAS
STILL OBSERVED AT MANY WRN CO SITES...BUT GJX RADAR ECHOES WERE
SLOWING SHRINKING. IF THIS TREND CONTINUES WILL PROBABLY LET THE
REMAINING WINTER HIGHLIGHTS EXPIRE AT MIDNIGHT THOUGH IT IS LIKELY
THAT AREAS OF LIGHT SNOW WILL PERSIST THROUGH THE NIGHT IN THE
COLD NW FLOW. COLD TEMPS IN STORE TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 318 PM MST FRI DEC 26 2014
UPPER LEVEL LOW CONTINUES TO MOVE EAST ACROSS THE FORECAST AREA
THIS AFTERNOON. LIGHT SNOW WILL CONTINUE TO FALL IN MANY LOCATIONS
BEFORE DIMINISHING THIS EVENING. HAVE ALLOW CURRENT HIGHLIGHTS FOR
LOWER VALLEYS TO EXPIRE AT 3PM AND HAVE CANCELLED HIGHLIGHTS FOR
ALL OF UTAH AND LOWER ELEVATIONS OF COLORADO WITH THE EXCEPTION OF
SOUTHWEST COLORADO 22/23 WHERE HIGHLIGHTS WILL CONTINUE. HAVE
ALSO ALLOWED HIGHLIGHTS TO CONTINUE FOR THE MOUNTAINS OF WESTERN
COLORADO.
AS THE UPPER LOW MOVES EAST OVERNIGHT...EXPECT PRECIPITATION TO
DIMINISH FROM WEST TO EAST THIS EVENING. THE BEST ACCUMULATION WILL
BE OVER COLORADO MOUNTAIN LOCATIONS WHERE A FEW INCHES OF
ADDITIONAL ACCUMULATION IS POSSIBLE. EXPECT VERY COLD TEMPERATURES
BY SATURDAY MORNING WITH 700 MB TEMPERATURES AROUND -16C.
NORTHERLY DRY FLOW WILL DOMINATE THE WEATHER PATTERN SATURDAY WITH
COLD TEMPERATURES AND PARTLY CLOUDY SKIES EXPECTED. THE NEXT
SYSTEM WILL DROP SOUTH INTO THE NORTHERN GREAT BASIN BY SATURDAY
NIGHT AND BRING INCREASING CLOUDS FROM THE NORTH WITH A SLIGHT
CHANCE OF SNOW OVER NORTHERN SECTIONS BY EARLY SUNDAY MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 318 PM MST FRI DEC 26 2014
A COMPLICATED STORM SYSTEM WILL DOMINATE THE WEATHER PATTERN FOR
SUNDAY INTO THE WORKWEEK. A LOW PRESSURE SYSTEM WILL DROP SOUTH
INTO THE GREAT BASIN REGION ON SUNDAY AND MONDAY BEFORE CLOSING
OFF OVER NEVADA BY TUESDAY. THE RESULTANT DEFORMATION ZONE WILL
SPREAD PERIODS OF LIGHT TO MODERATE SNOW OVER THE NORTHERN
SECTIONS OF COLORADO ON SUNDAY MORNING AND SPREAD ACROSS THE
CENTRAL AND SOUTHERN MOUNTAINS LATER SUNDAY AND CONTINUE INTO
TUESDAY. MODELS ARE STILL SHOWING SOME INCONSISTENCIES REGARDING
TIMING AND LOCATION OF THE TRACK OF THIS SYSTEM. HOWEVER...BASED
ON CURRENT GUIDANCE EXPECT A PERIOD OF UNSETTLED WEATHER THROUGH
TUESDAY WITH THE POTENTIAL FOR MODERATE ACCUMULATIONS ESPECIALLY
OVER MOUNTAIN LOCATIONS WHICH MAY REQUIRE WINTER WEATHER
HIGHLIGHTS. BY MIDWEEK THE CLOSED LOW IS FORECASTED TO EJECT
SLOWLY EAST...SOUTH OF OUR FORECAST AREA WITH SOME POTENTIAL
IMPACT FOR SOUTHERN SECTIONS OF THE FORECAST AREA BUT FORECAST
CONFIDENCE IS LOW ON THIS MODEL SOLUTION AT THIS TIME.
TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 937 PM MST FRI DEC 26 2014
THE UPPER LEVEL TROUGH WILL SLOWLY SLIP EASTWARD TONIGHT WITH
FLOW ALOFT BECOMING NORTHWEST. MVFR CIGS/VSBY WITH AREAS OF LIGHT
SNOW WILL PERSIST OVER NW CO AND ALL CO MTNS OVERNIGHT WITH MTN
TOPS OBSCURED. LCL IFR CIGS. CONDITIONS IMPROVE OVER ERN UT AND
THE FOUR CORNERS OVERNIGHT AND AFTER 12Z-15Z ACROSS WRN CO AS HIGH
PRESSURE TEMPORARILY BUILDS IN. HIGH CLOUDS SPREAD ACROSS NERN UT
AND NWRN CO SATURDAY AFTERNOON AS A PRECURSOR TO THE NEXT POTENTIAL
STORM SUNDAY-MONDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ003-
017-018.
WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ004-009-
010-012-013-019-022-023.
UT...NONE.
&&
$$
UPDATE...JAD
SHORT TERM...MPM
LONG TERM...MPM
AVIATION...JAD
AREA FORECAST DISCUSSION...UPDATED
NWS COLUMBIA SC
956 PM EST SUN DEC 28 2014
.SYNOPSIS...
A COLD FRONT TO THE WEST WILL SLOWLY MAKE ITS WAY ACROSS THE AREA
TONIGHT AND MONDAY BRINGING A CONTINUED CHANCE FOR RAIN. DRY WEATHER
AND COOLER TEMPERATURES WILL RETURN BY MID-WEEK AS HIGH PRESSURE
DOMINATES. ANOTHER COLD FRONT WILL BRING THE THREAT OF RAIN NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
EVENING SURFACE MAP SHOWS A WAVY FRONT EXTENDING FROM WESTERN VA
SOUTHWESTWARD ALONG THE FOOTHILLS OF THE APPALACHIANS TO NEAR ATL
TO SURFACE LOW PRESSURE IN THE WESTERN FL PANHANDLE. WATER VAPOR
IMAGERY CONTINUES TO SHOW AN UPPER RIDGE OVER CUBA WITH A LARGE
POSITIVELY TILTED UPPER TROUGH COVERING MUCH OF THE WESTERN PART
OF THE COUNTRY. SHORTWAVE ENERGY ROUNDING THE BASE OF THE UPPER
TROUGH IS FORECAST TO LIFT NORTHEASTWARD TONIGHT AND WILL INITIATE
ANOTHER ROUND OF RAIN ALONG AND AHEAD OF THE COLD FRONT THAT WILL
CROSS THE AREA ON MONDAY. UPPER SUPPORT WILL BE PRESENT IN THE
FORM OF UPWARD VERTICAL MOTION ASSOCIATED WITH THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET.
POP FORECAST GENERALLY REMAINS UNCHANGED WITH LOW POPS OVER THE
NEXT COUPLE OF HOURS AND THEN AN INCREASE IN POPS LATE TONIGHT
THROUGH MONDAY MORNING TO CATEGORICAL RANGE. TEMPERATURES WILL NOT
CHANGE MUCH OVERNIGHT UNDER THICK CLOUD COVER AND ENHANCED
DEWPOINTS IN THE 50S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
THE COLD FRONT WILL BE SLOW TO EXIT THE FORECAST AREA AS SEVERAL
WEAK WAVES ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY. THE CHANCE
FOR RAIN CONTINUES MONDAY...THEN BEGINS TO TAPERS OFF LATE MONDAY
AFTERNOON AND MONDAY NIGHT AS THE COLD FRONT MOVES OFFSHORE AND
DRIER AIR FILTERS IN FROM THE WEST BY TUESDAY MORNING.
ABOVE NORMAL TEMPERATURES MONDAY WILL DROP BACK INTO THE 50S FOR
TUESDAY. OVERNIGHT LOWS IN THE 40S MONDAY NIGHT WILL COOL INTO
THE 30S TUESDAY NIGHT GIVEN MOSTLY CLEAR SKIES AND LIGHT WINDS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG CANADIAN HIGH PRESSURE WILL REMAIN CENTERED OFF TO THE WEST
OF THE FORECAST AREA ON WEDNESDAY AND THEN GRADUALLY PUSH
EASTWARD INTO THE SOUTHEAST ON THURSDAY. THE HIGH WILL THEN PUSH
OFF THE COAST FRIDAY. DRY WEATHER IS FORECAST WEDNESDAY THOUGH
THURSDAY NIGHT...THEN MOISTURE IS EXPECTED TO RETURN THROUGH THE
DAY FRIDAY AS A WARM FRONT LIFTS NORTHWARD FROM THE GULF COAST
STATES. MODELS INCREASE RAIN CHANCES FRIDAY INTO SATURDAY.
TEMPERATURES WILL BE ON THE CHILLY SIDE WEDNESDAY INTO
FRIDAY...ESPECIALLY MORNING LOWS...BUT TEMPS WILL INCREASE FRIDAY
INTO SATURDAY WHICH WILL KEEP READINGS WARM ENOUGH THAT THE PRECIP
WILL BE ALL LIQUID.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
VFR/MVFR EXPECTED UNTIL AROUND 06Z...BECOMING IFR
OVERNIGHT...POSSIBLY IMPROVING TO MVFR BY MONDAY AFTERNOON.
LATEST RADAR COMPOSITE CONTINUES TO SHOW A LULL IN PRECIPITATION
ACROSS THE FORECAST AREA. LATEST HRRR INDICATING RAIN WILL RESUME
DURING THE PREDAWN HOURS AS A SHORTWAVE APPROACHES FROM THE WEST.
EXPECT PRIMARILY MVFR CONDITIONS EARLY IN THE TAF PERIOD BECOMING
IFR ESPECIALLY AFTER 06Z MONDAY. DO NOT SEE MUCH IN THE WAY OF
IMPROVEMENT UNTIL AFTER 17Z MONDAY AS THE PRECIPITATION PUSHES EAST.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE LATE MONDAY
THROUGH EARLY TUESDAY AS THE NEXT FRONTAL SYSTEM MOVES INTO THE AREA
AND STALLS JUST TO THE SOUTH.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR SCZ030.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
627 PM EST SUN DEC 28 2014
.SYNOPSIS...
A COLD FRONT TO THE WEST WILL SLOWLY MAKE ITS WAY ACROSS THE AREA
TONIGHT AND MONDAY BRINGING A CONTINUED CHANCE FOR RAIN. DRY WEATHER
AND COOLER TEMPERATURES WILL RETURN BY MID-WEEK AS HIGH PRESSURE
DOMINATES. ANOTHER COLD FRONT WILL BRING THE THREAT OF RAIN NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
EARLY EVENING UPDATE TO AMEND POP FORECAST TO ACCOUNT FOR LULL IN
PRECIPITATION ACROSS THE REGION. INITIAL SHORTWAVE
ENERGY...MOISTURE FLUX AND ASSOCIATED PRECIPITATION HAS SHIFTED
OFF TO THE NORTHEAST WHILE THE NEXT WAVE AND ASSOCIATED ROUND OF
PRECIP IS SET TO ARRIVE AFTER MIDNIGHT TONIGHT. HAVE DROPPED POPS
FOR THE NEXT FEW HOURS AND THEN RAMP THEM BACK UP LATE THIS
EVENING INTO THE LIKELY/CATEGORICAL RANGE AFTER 06Z IN THE WESTERN
MIDLANDS WHERE THE BEST MOISTURE CONVERGENCE ALONG THE APPROACHING
COLD FRONT WILL BE...AND ADDITIONAL SUPPORT FROM THE RIGHT
ENTRANCE REGION OF THE UPPER JET. TEMPERATURES WILL REMAIN MILD
OVERNIGHT WITH LOW CLOUDS IN PLACE AND WELL ABOVE NORMAL DEWPOINTS
IN THE 50S/60S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
THE COLD FRONT WILL BE SLOW TO EXIT THE FORECAST AREA AS SEVERAL
WEAK WAVES ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY. THE CHANCE
FOR RAIN CONTINUES MONDAY...THEN BEGINS TO TAPERS OFF LATE MONDAY
AFTERNOON AND MONDAY NIGHT AS THE COLD FRONT MOVES OFFSHORE AND
DRIER AIR FILTERS IN FROM THE WEST BY TUESDAY MORNING.
ABOVE NORMAL TEMPERATURES MONDAY WILL DROP BACK INTO THE 50S FOR
TUESDAY. OVERNIGHT LOWS IN THE 40S MONDAY NIGHT WILL COOL INTO
THE 30S TUESDAY NIGHT GIVEN MOSTLY CLEAR SKIES AND LIGHT WINDS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG CANADIAN HIGH PRESSURE WILL REMAIN CENTERED OFF TO THE WEST
OF THE FORECAST AREA ON WEDNESDAY AND THEN GRADUALLY PUSH
EASTWARD INTO THE SOUTHEAST ON THURSDAY. THE HIGH WILL THEN PUSH
OFF THE COAST FRIDAY. DRY WEATHER IS FORECAST WEDNESDAY THOUGH
THURSDAY NIGHT...THEN MOISTURE IS EXPECTED TO RETURN THROUGH THE
DAY FRIDAY AS A WARM FRONT LIFTS NORTHWARD FROM THE GULF COAST
STATES. MODELS INCREASE RAIN CHANCES FRIDAY INTO SATURDAY.
TEMPERATURES WILL BE ON THE CHILLY SIDE WEDNESDAY INTO
FRIDAY...ESPECIALLY MORNING LOWS...BUT TEMPS WILL INCREASE FRIDAY
INTO SATURDAY WHICH WILL KEEP READINGS WARM ENOUGH THAT THE PRECIP
WILL BE ALL LIQUID.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
GENERALLY MVFR EXPECTED THIS EVENING...DETERIORATING TO IFR
OVERNIGHT. SOME IMPROVEMENT BACK TO MVFR POSSIBLE BY MONDAY
AFTERNOON.
LATEST RADAR COMPOSITE SHOWING A LULL IN PRECIPITATION ACROSS THE
FORECAST AREA EARLY THIS EVENING. LATEST HRRR INDICATING RAIN WILL
RESUME DURING THE OVERNIGHT HOURS AS A SHORTWAVE APPROACHES FROM THE
WEST. EXPECT PRIMARILY MVFR CONDITIONS DURING THE EVENING HOURS
BECOMING IFR ESPECIALLY AFTER 06Z MONDAY. DO NOT SEE MUCH IN THE WAY
OF IMPROVEMENT UNTIL AFTER 17Z MONDAY AS THE PRECIPITATION PUSHES EAST
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE LATE MONDAY
THROUGH EARLY TUESDAY AS THE NEXT FRONTAL SYSTEM MOVES INTO THE AREA
AND STALLS JUST TO THE SOUTH.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR SCZ030.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
337 PM CST SAT DEC 27 2014
.SHORT TERM...
307 PM CST
REMAINDER OF THIS AFTERNOON AND TONIGHT...
A STRONG COLD FRONT IS TRACKING ACROSS THE REGION...USHERING IN MUCH
COOLER AIR ALONG WITH SOME SCT LIGHT PCPN. AS OF 230PM CDT...THE
SFC FRONTAL BOUNDARY EXTENDED FROM WESTERN LOWER MICHIGAN...TO
EAST-CENTRAL IL...TO SERN MO. WINDS HAVE BEEN GUSTING TO ARND 30
MPH FOLLOWING THE FROPA WHILE VEERING FROM SWLY TO WLY.
TEMPERATURES ARE SLOWLY DROPPING OFF WITH THE FROPA AND THE BULK OF
THE PCPN IS POST-FRONTAL AS A STRONG LOW LEVEL JET HAS SET UP ALONG
AN ELEVATED BAROCLINIC ZONE. SOME SCT RAIN IS STILL POSSIBLE OVER
NWRN IN AND ECNTRL IL AHEAD OF THE FRONT...BUT AS COOLER AIR FILTERS
IN BEHIND THE BOUNDARY...LIQUID PCPN IN THE POST-SFC FRONTAL
BOUNDARY SHOULD TRANSITION INTO A MIX OF RAIN...SNOW AND POSSIBLE
SOME GRAPPLE. THE SHARPER TEMPERATURE DROPOFF WILL OCCUR LATER THIS
AFTERNOON AND THROUGH THIS EVENING AS A SECONDARY TROUGH ASSOCIATED
WITH A SURGE OF COOLER AIR PUSHED ACROSS THE EVENING WHICH WILL BE
ACCOMPANIED BY A WIND SHIFT TO WLY-WNWLY. ANY LINGERING PCPN SHOULD
PUSH END OVER NWRN IL-ECNTRL IL DURG THE LATE EVENING HOURS AND
TEMPERATURES OVERNIGHT SHOULD RANGE FROM ARND 20F OVER THE ROCKFORD
AREA TO THE UPPER 20S EAST OF THE I-55 CORRIDOR.
KREIN
&&
.LONG TERM...
307 PM CST
SUNDAY THROUGH SATURDAY...
THE PASSAGE OF THE SYSTEM CURRENTLY MOVING THROUGH THE REGION IS A
SIGNAL OF A MAJOR PATTERN SHIFT FROM THE UNSEASONABLY WARM
CONDITIONS OF RECENT DAYS BACK TO MORE SEASONABLE CONDITIONS AS THE
SHORT-WAVELENGTH...HIGH AMPLITUDE TROUGH SHEARS OUT INTO BROAD WEAK
TROUGHING ALOFT THROUGH THE REMAINDER OF THE WEEKEND. THE GENERAL
TEMPERATURE TREND FOR SUNDAY AND INTO EARLY NEXT WEEK WILL BE FOR A
SLOW COOLING TREND UNDER BROAD...WEAK HEIGHT FALLS ALOFT. A
STRONGER SURGE OF COLD AIR WITH A SERIES OF NRN STREAM SHORTWAVES
WILL USHER IN THE TRUE COLD AIR BY MONDAY NIGHT AND TUESDAY WITH
TEMPERATURES MONDAY MORNING DROPPING OFF INTO THE LOWER TEENS OVER
THE ROCKFORD AREA TO AROUND 20F EAST OF THE I-55 CORRIDOR. THE
UPPER LEVEL PATTERN WILL SET UP TO MORE ZONAL OVER THE SRN CONUS
AS THE MAIN JET PATTERN SHIFTS TO THE SOUTH WHILE POLAR-SOURCED
SHORT WAVE ENERGY DROPS INTO THE UPPER MISSISSIPPI VALLEY AND
THROUGH THE MIDWEST AND GREAT LAKES REGIONS THROUGH THE REMAINDER OF
NEXT WEEK. THE LARGE SCALE PATTERN WILL ALSO BECOME LESS
PROGRESSIVE...WITH THE LONGER RANGE GUIDANCE INDICATING A CUT OFF
LOW DIGGING INTO SRN CALIFORNIA AND VERY SLOWLY TRACKING EWD THROUGH
THE DESERT SOUTHWEST BY LATE NEXT WEEK WHILE SUB-TROPICAL HIGH
PRESSURE REMAINS PARKED OVER THE WESTERN CARIBBEAN AND GREATER
ANTILLES. THE SLOWING PROGRESSION TO THE LONGWAVE PATTERN WILL IN
TURN SET UP A PERIOD WITH A SERIES OF NRN STREAM SHORTWAVES KEEPING
A STEADY STREAM OF SEASONABLY COLD AIR INTO THE REGION. THE NEXT
CHANCE FOR ANY PCPN ACROSS THE AREA WILL BE MONDAY AFTERNOON INTO
TUESDAY AS A COLD FRONT ON THE LEADING EDGE OF AN ARCTIC AIRMASS
TRIES TO SQUEEZE OUT A LITTLE SNOW IN A RELATIVELY DRY ENVIRONMENT.
LITTLE OR NO ACCUMULATION IS EXPECTED OVER MUCH OF THE AREA...
PERHAPS A DUSTING WITH SCT SNOW SHOWERS. HOWEVER...AS SFC HIGH
PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE
GREAT LAKES REGIONS...A PERIOD OF GENERALLY NORTHERLY FLOW WILL SET
UP OVER LAKE MICHIGAN...AND THERE WILL BE A CHANCE FOR SOME LAKE
EFFECT SNOW INITIALLY ALONG THE ILLINOIS LAKE MICHIGAN SHORE MONDAY
EVENING AND THEN GRADUALLY TRANSITIONING TO THE EAST OVER NWRN
INDIANA MONDAY NIGHT INTO TUESDAY MORNING AS FLOW BACKS MORE NWLY.
IT IS STILL A LITTLE EARLY TO DISCUSS ACCUMULATIONS WITH LAKE EFFECT
SNOW AT THIS POINT...BUT HAVE INCREASED POPS TO LIKELY FOR THE
FAVORED LAKE EFFECT AREAS AND WOULD ANTICIPATE SOME MEASURABLE
ACCUMULATION. MIDWEEK SHOULD BE DRY...BUT WITH THE LOWEST
TEMPERATURES OF THE PERIOD AS THE SFC HIGH PRESSURE SETTLES INTO THE
LOWER MISSISSIPPI VALLEY AND SERN CONUS. BY LATE NEXT WEEK...THE
LONGER RANGE GUIDANCE IS INDICATING THAT THE CUT OFF LOW DROPPING
INTO THE DESERT SOUTHWEST WILL FINALLY BEGIN TO LIFT OUT TO THE
NORTHEAST WHILE A NRN STREAM SHORTWAVE DROPS THROUGH THE NRN PLAINS
TO THE UPPER MISSISSIPPI VALLEY. HOWEVER...WHILE THE LONGER RANGE
GUIDANCE IS IN RELATIVELY DECENT AGREEMENT ON THE TREND...THERE ARE
CONSIDERABLE DIFFERENCES IN THE TIMING WITH THE GFS MUCH FASTER THAN
THE ECMWF OR GEM. GIVEN THAT SOUTHWEST CUT-OFF LOWS TEND TO LINGER
LONGER THAN THE MODELS LIKE TO FORECAST...HAVE TRENDED THE LONGER
TERM FORECAST CLOSER TO THE SLOWER SOLUTIONS...AND WOULD NOT BE
SURPRISED TO SEE THE MODELS TREND EVEN SLOWER THAN CURRENTLY
INDICATED. SO...WILL LIMIT POPS TO CHANCE LEVELS WITH TEMPERATURES
CONDUCIVE TO SNOW FOR NOW.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST WINDS GUSTING ARND 25 KT THROUGH THE AFTN.
* MVFR CIGS PERSISTING THROUGH THE EVENING.
JEE
//DISCUSSION...UPDATED 18Z...
THE COLD FRONT EXTENDS FROM PWK THROUGH FORD COUNTY IL AND IT WILL
CONTINUE EAST WITH 30KT GUSTS ALONG THE FRONT. SCATTERED LIGHT
SHOWERS ARE ALONG THE FRONT AND STILL NOT EXPECTING ANY
SIGNIFICANT IMPACT FROM THEM AS THEY QUICKLY SHIFT EAST OF THE
TERMINALS. IFR CIGS LIFT TO MVFR BEHIND THE FRONT AS WELL.
VFR CONDITIONS EXTEND FROM CENTRAL MN THROUGH NE AND EXPECTING
CIGS TO SCATTER OUT OVERNIGHT. HIGH PRESSURE SPREADS IN AND NW
WINDS DIMINISH TO LESS THAN 20 KT OVERNIGHT. VERY WEAK
WINDS...LESS THAN 5 KT...VARY FROM WEST OR SOUTHWEST OVER RFD
TOMORROW TO NORTHWEST TO NORTH OVER THE EASTERN TERMINALS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIG TRENDS...MEDIUM CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
336 PM CST
AS LOW PRESSURE CONTINUES TO LIFT NORTHEAST THROUGH THE CENTRAL
GREAT LAKES THIS AFTERNOON...A COLD FRONT WILL PUSH THROUGH THE
REMAINING AREAS OVER THE LAKE. ON THE BACKSIDE OF THIS SYSTEM AND
WITH THE ARRIVAL OF MUCH COLDER AIR OVER THE WATER...A ONE TO
THREE HOUR WINDOW OF GALES/GUSTS DID OCCUR THIS PAST AFTERNOON
OVER MUCH OF THE LAKE. THE PEAK OF THESE HIGHEST GUSTS HAS ALREADY
OCCURRED AND EXPECT A DOWNWARD TREND IN SPEEDS FROM THIS POINT
FORWARD. NONETHELESS...A BRIEF GALE FORCE GUST CANT BE RULED OUT
HERE IN THE VERY NEAR TERM. A WEST NORTHWEST WIND CAN BE EXPECTED
FOR THE REMAINDER OF THE NIGHT...AS WINDS DIMINISH AND WAVES
SUBSIDE. A PERIOD OF NORTHERLY WINDS WILL BE OBSERVED OVER THE
ENTIRE LAKE THROUGH EARLY NEXT WEEK...AS HIGH PRESSURE BUILDS
ACROSS THE REGION.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
313 PM CST Sat Dec 27 2014
.SHORT TERM...(Tonight)
ISSUED AT 313 PM CST SAT DEC 27 2014
Low clouds, drizzle, light rain showers still ongoing across the
forecast area this afternoon. Cold front about out of ILX
area...just NW of Lawrenceville. Some flakes mixing into the precip
on the extreme NW edge of the post frontal echos on radar. Front
progression somewhat steady although running into more parallel flow
aloft. Cold dense air from the NW really colder behind the post
frontal precip spread across the radar mosaic. Timing of the cold
air a minor concern as time progresses. Ground temps still close to
40 degrees, but with the arrival of the freezing temps, some
elevated surfaces could develop some slick spots. The arrival of the
coldest air will be after the precip has come to an end...so
freezing should be confined to the residual moisture/puddles from
todays drizzle/rain. Another issue with the overnight forecast is
the cloud cover. GFS is quick to break it out...a little faster than
is currently represented on sat imagery. NAM is far cloudier,
trapping the moisture in the boundary layer and preventing the mix
out entirely. RUC looking more like the NAM with representing the
developing inversion behind the boundary. Plenty of dry air up
there, but how quickly it will erode through the clouds is a huge
question mark. Covered in cirrus all day, not convinced the diurnal
influence on the clouds is enough to erode them at sunset.
Considering how quickly sunset is approaching, going to split the
difference more or less with a slower clearing out...but not quite
as trapped as the NAM. Some breaking up could be seen in the far NW,
and forecast low temps are considerably cooler as a result.
However, going cloudier overall through the night.
&&
.LONG TERM...(Sunday through Saturday)
ISSUED AT 313 PM CST SAT DEC 27 2014
High pressure behind the front will bring dry weather to the area
for tomorrow through Monday. However, this mild high pressure area
will be temporary as a stronger/colder high pressure area drops into
the region Tuesday. A weak boundary will be between these two high
pressure areas, but it will have very little moisture to work with.
This will be an Arctic front with much colder air behind it. Any
precip with this Arctic front will be very light and could occur
Monday night. With the colder temps and limited moisture, only pcpn
expected will be flurries. Also believe this will be across the
northern 2/3rds of the CWA, leaving the southeastern CWA dry as the
area flurries moves east.
Temps will be around normal tomorrow and Monday, but then drop to
below normal for Tue as the Arctic cold high pressure moves in.
Cold, dry Arctic high pressure will dominate the area for days 3-5,
but as the high pressure modifies and moves into southeastern US,
temps will begin to warm gradually and a weather system will develop
in the southwestern US and begin to move out into the plains. With
high pressure to the east and a surface low pressure area to the
west, warmer air will not be the only thing to return to the area.
Moisture will also return and this will bring pcpn to the area as
the moisture interacts with a warm front and lifts northward into
the area. P-type could be very interesting and be dependent on the
surface temperature and temps in the lower levels. Models
forecasting temps above zero at 850mb over the area, which would
indicate rain. However, surface temps look to be below freezing Fri
night; and this could mean frozen pcpn possible. Considering Fri
through Sat is Day6-7, will not get too detailed on pcpn type and
just go with snow or rain, or a mix of rain and snow. Thinking
mostly rain on Friday with a mix in the north, then a mix becoming
all snow on Fri night, and then all snow in the east on Sat. Am
expecting the p-type to change over the next several days, and when
the event becomes better defined by the models and closer.
As mentioned earlier, temps will start cold and then gradually warm
during the week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1135 AM CST SAT DEC 27 2014
Conditions behind the front improving to MVFR, and IFR still ahead
of the boundary. DEC in midst of fropa, and CMI to follow. Tempos
in to hold for lower cigs and lesser vis associated with the
front. Winds more westerly/northwesterly, but a more southwesterly
flow aloft. Major concern is the longevity of the lower clouds
behind the boundary. Where as the sfc boundary may race out ahead
the remaining llvl moisture may contribute to keeping the clouds
around a little longer than expected. Models not really picking up
on the current situation. All the weak returns out to the west and
SW also point to abundant moisture. Think the sky will eventually
scatter, though later than prev expected.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HJS
LONG TERM...Auten
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
155 PM CST SAT DEC 27 2014
.SHORT TERM...
245 AM CST
THROUGH SUNDAY...
WE ARE LIVING ON BORROWED TIME WITH 850 MB TEMPS SITTING ABOVE
ZERO...BUT THAT WILL BE A THING OF THE PAST COME THIS AFTERNOON. BUT
FIRST OFF...LIGHT RAIN/DRIZZLE IN EAST CENTRAL ILLINOIS AND INTO NW
INDY IS ASSOCIATED WITH THE SLIGHTLY BETTER ISENTROPIC LIFT/MOISTURE
ADVECTION. THIS WILL DRIFT OFF TO THE EAST THIS MORNING AND WILL
GRAZE OUR SE COUNTIES. MEANWHILE A SECOND AREA OF LIGHT RAIN
CONTINUES OVER NORTHWEST/NORTH CENTRAL ILLINOIS CLOSER TO THE NORTHWARD
MOVING LOW AND EASTWARD ADVANCING COLD FRONT. MUCH OF OUR AREA FINDS
ITSELF IN AN AREA OF WEAKER ISENTROPIC LIFT AND A BIT REMOVED FROM
THE FRONTAL INFLUENCE. THEREFORE...EXPECT SCATTERED LIGHT
RAIN/DRIZZLE IN BETWEEN THAT SHOULD BE LESS ORGANIZED THAN THESE TWO
AREAS.
THE SURFACE LOW IN IOWA CONTINUES TO DEEPEN AND PUSH NE TO NORTHERN
LAKE MICHIGAN THIS MORNING. THE BETTER UPPER DYNAMICS WITH THE
FRONT ARE WITH THE SHORTWAVE MOVING THROUGH IOWA...AND THIS HEADS
NORTHWEST OF OUR AREA TODAY AS WELL. ENOUGH FRONTAL CONVERGENCE
EXISTS TO CARRY A LOW POP RAIN MENTION THROUGH THE MORNING THOUGH
MANY AREAS STAY DRY. THE BETTER MID LEVEL FORCING/FRONTOGENESIS
ARRIVES WITH THE FRONT THIS AFTERNOON BUT MOISTURE IS
LACKING...THEREFORE EXPECT A LARGELY DRY AFTERNOON EXCEPT IN NW
INDIANA AND EASTERN PORTIONS OF ILLINOIS. WITH A STRENGTHENING
UPPER JET OVERHEAD...EXPECT BREEZY SOUTHWEST WINDS AHEAD OF THE
FRONT...THEN GUSTY WEST WINDS BEHIND IT. AFTER A PLEASANT WARM UP
THE LAST FEW DAYS...THIS FRONT DOES HAVE SOME KICK TO IT...AND
WHILE THE COLD AIR DOES NOT NECESSARILY COME SCREAMING IN...DO
EXPECT A RETURN TO REALITY AND MORE SEASONAL CONDITIONS.
THE COLD FRONT WILL BE THROUGH TONIGHT. ANY LINGERING PRECIP IN OUR
FAR SE COUNTIES OF NW INDIANA MAY SEE A LIGHT RAIN/SNOW MIX BEFORE
PRECIP ENDS. OTHERWISE HIGH PRESSURE NOSES IN FROM THE WEST BRINGING
GRADUAL CLEARING OVERNIGHT. READINGS OVERNIGHT DROP INTO THE 20S
TO AROUND 30. SUNDAY LOOKS TO BE GENERALLY SUNNY BUT SEASONALLY
COLD AS THE MAIN UPPER LOW PASSES THROUGH SOUTHERN CANADA.
KMD
&&
.LONG TERM...
245 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
STRONGER CANADIAN HIGH PRESSURE...WILL BE KNOCKING AT OUR DOOR ON
SUNDAY NIGHT...AND WILL SEND A WEAK BACK DOOR COLD FRONT DOWN THE
LAKE. THE LEADING EDGE OF THIS SECONDARY SURGE OF COLD AIR WILL
TRIGGER A SIGNIFICANTLY COLDER STRETCH OF WEATHER TO KICK OFF THE
LAST FEW DAYS OF 2014. THERE MAY BE SOME WEAK LAKE EFFECT SNOW
SHOWERS GETTING INTO NE ILLINOIS...OTHERWISE INCREASING CLOUDS AND
COLDER. THEN AS THE TRULY ARCTIC AIR SPILLS IN MONDAY NIGHT...WE MAY
SEE SOME SNOW SHOWERS ALONG THE BAROCLINIC ZONE. MOISTURE IS NOT
IMPRESSIVE WITH THE FRONT...BUT THE COMBINED NE FLOW OFF THE LAKE
WITH MORE SIGNIFICANT INVERSION HEIGHTS AND MUCH COLDER AIR MAY
ALLOW FOR LAKE ENHANCEMENT AND SOME BETTER ACCUMULATION POTENTIAL.
THEN THE CHILL ENSUES FOR SEVERAL DAYS OF HIGHS ON EITHER SIDE OF 20
AND LOWS IN THE SINGLE DIGITS AND TEENS AS WE REMAIN IN NW FLOW. THE
UPSIDE...LIKELY SOME MORE SUN TO ENJOY TO END THE YEAR...AS ANY
SHORTWAVE ENERGY ROTATING THROUGH FROM THE CANADIAN VORTEX WILL
EITHER REMAIN NORTH OR GENERALLY BE WEAK AS THE ONE THAT COMES
THROUGH TUESDAY NIGHT. SOME MODIFICATION TO THE COLD AIR MASS
ARRIVES ON NEW YEARS DAY AND MORE SO FRIDAY AS WE RETURN TO
SOUTHERLY FLOW. AS THIS OCCURS...WILL HAVE TO WATCH IF LOW
PRESSURE THAT CLOSES OFF OVER CALIFORNIA EARLIER IN THE WEEK
PHASES WITH THE NORTHERN STREAM LOW OR REMAINS FARTHER SOUTH AS
THIS WILL HAVE IMPLICATIONS FOR ANY PRECIPITATION CHANCES TOWARD
WEEKS END.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST WINDS GUSTING ARND 25 KT THROUGH THE AFTN.
* MVFR CIGS PERSISTING THROUGH THE EVENING.
JEE
//DISCUSSION...UPDATED 18Z...
THE COLD FRONT EXTENDS FROM PWK THROUGH FORD COUNTY IL AND IT WILL
CONTINUE EAST WITH 30KT GUSTS ALONG THE FRONT. SCATTERED LIGHT
SHOWERS ARE ALONG THE FRONT AND STILL NOT EXPECTING ANY
SIGNIFICANT IMPACT FROM THEM AS THEY QUICKLY SHIFT EAST OF THE
TERMINALS. IFR CIGS LIFT TO MVFR BEHIND THE FRONT AS WELL.
VFR CONDITIONS EXTEND FROM CENTRAL MN THROUGH NE AND EXPECTING
CIGS TO SCATTER OUT OVERNIGHT. HIGH PRESSURE SPREADS IN AND NW
WINDS DIMINISH TO LESS THAN 20 KT OVERNIGHT. VERY WEAK
WINDS...LESS THAN 5 KT...VARY FROM WEST OR SOUTHWEST OVER RFD
TOMORROW TO NORTHWEST TO NORTH OVER THE EASTERN TERMINALS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIG TRENDS...MEDIUM CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1142 AM CST Sat Dec 27 2014
.UPDATE...
ISSUED AT 1033 AM CST SAT DEC 27 2014
Weak cold front making its way through the state this morning and
has just passed over I-55 according to the depiction on radar and
the wind shift to more westerly in the obs. Cooler temps on the way
and a non-diurnal trend anticipated for locations behind the
front. Some minor precip along the boundary, but majority of radar
returns post-frontal not producing much in the way of measurable precip,
with the vast majority being drizzle. Only a few obs even picking
up on that. Not going to update the pops too much as the better
chances for rain remain in the southeast for the rest of the day.
Some small updates here and there, but nothing large scale. Will
reissue the zones only to refresh the morning wording closer to
noon.
&&
.SHORT TERM...(Today)
ISSUED AT 324 AM CST SAT DEC 27 2014
08z/2am surface analysis shows 1013mb low just north of KMLI, with
frontal boundary extending southwestward into Texas. Airmass ahead
of the front was initially quite dry as evidenced by the 00z KILX
upper air sounding: however, shallow low-level moisture has been on
the increase throughout the night. Surface dewpoints have reached
the middle 40s across central Illinois, while a plume of 50s
dewpoints is noted further upstream pushing into Arkansas. LAPS
soundings show this increasing moisture, with most local profiles
now saturated below 700mb. As low pressure tracks further
northeastward into Wisconsin, it will pull the cold front into the
area later this morning, then to the Indiana border by mid to late
afternoon. Continued moisture pooling along/ahead of the front
will result in increasingly deep moisture profiles, particularly
across the E/SE CWA this afternoon. HRRR suggests only scattered
light showers across much of the area this morning, then shows
more widespread precipitation developing along/east of I-57 this
afternoon. Think this solution makes sense as front gradually taps
into increasing amounts of Gulf moisture as it moves further east.
As a result, will carry chance PoPs across the western half of the
CWA throughout the day, with chance PoPs increasing to likely
across the E/SE this afternoon. With cold front passing through
the area, high temperatures will be achieved this morning,
followed by brisk westerly winds and falling temperatures later in
the day. Due to very mild current temps, have generally gone 2-4
degrees above MAV guidance numbers. End result will be highs in
the upper 40s and lower 50s, with temps dropping into the 30s
along/west of I-55 during the afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 324 AM CST SAT DEC 27 2014
Cold front will slowly push eastward into the Ohio River Valley
tonight, with clouds and showers lingering across the E/SE through
at least the evening hours. NAM is fastest with the departure of
the precip, while GFS tends to keep it around through the entire
night. Based on slow forward movement of the front, have trended
toward the slower GFS. As a result, will maintain low chance PoPs
along/south of I-70 through the overnight hours. As temperatures
slowly fall into the lower to middle 30s across this area, any
lingering rain showers may mix with or change to light snow late.
Further northwest, skies will clear across the Illinois River
Valley, allowing lows to bottom out in the lower to middle 20s.
Sunshine and seasonably cool temps in the 30s will prevail Sunday
into Monday, before a surge of cold air arrives next week. Models
have been consistently showing strong 1050mb high building southward
out of western Canada into the central CONUS by Tuesday/Wednesday.
Weak synoptic lift along the leading edge of the cold air may be
enough to trigger a few flurries across the area Monday night, but
the main story will be the colder temps. High temps will remain in
the 20s Tuesday/Wednesday, while overnight lows dip into the single
digits and teens. After that, Canadian high pressure will gradually
slide east of the region, allowing a southern stream system to
approach by the end of the week. Model solutions vary with this
feature, so forecast confidence remains low at this point. ECMWF
aggressively brings precip northward into south-central Illinois as
early as Thursday night, while the GFS is about 12-18 hours
slower. Meanwhile, the GEM suggests the system may remain largely
southeast of the area across the Ohio River Valley. Given the
uncertainties, have opted to go with a dry forecast Thursday night,
and to slow precip onset on Friday. Have trimmed Friday PoPs to
just slight chance, with higher precip chances arriving Friday night
into Saturday. Think slower/colder is the way to go, especially
given the Canadian airmass that will initially be in place. End
result will be a chance of snow or a rain/snow mix mainly Friday
night into Saturday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1135 AM CST SAT DEC 27 2014
Conditions behind the front improving to MVFR, and IFR still ahead
of the boundary. DEC in midst of fropa, and CMI to follow. Tempos
in to hold for lower cigs and lesser vis associated with the
front. Winds more westerly/northwesterly, but a more southwesterly
flow aloft. Major concern is the longevity of the lower clouds
behind the boundary. Where as the sfc boundary may race out ahead
the remaining llvl moisture may contribute to keeping the clouds
around a little longer than expected. Models not really picking up
on the current situation. All the weak returns out to the west and
SW also point to abundant moisture. Think the sky will eventually
scatter, though later than prev expected.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1115 AM CST SAT DEC 27 2014
.SHORT TERM...
245 AM CST
THROUGH SUNDAY...
WE ARE LIVING ON BORROWED TIME WITH 850 MB TEMPS SITTING ABOVE
ZERO...BUT THAT WILL BE A THING OF THE PAST COME THIS AFTERNOON. BUT
FIRST OFF...LIGHT RAIN/DRIZZLE IN EAST CENTRAL ILLINOIS AND INTO NW
INDY IS ASSOCIATED WITH THE SLIGHTLY BETTER ISENTROPIC LIFT/MOISTURE
ADVECTION. THIS WILL DRIFT OFF TO THE EAST THIS MORNING AND WILL
GRAZE OUR SE COUNTIES. MEANWHILE A SECOND AREA OF LIGHT RAIN
CONTINUES OVER NORTHWEST/NORTH CENTRAL ILLINOIS CLOSER TO THE NORTHWARD
MOVING LOW AND EASTWARD ADVANCING COLD FRONT. MUCH OF OUR AREA FINDS
ITSELF IN AN AREA OF WEAKER ISENTROPIC LIFT AND A BIT REMOVED FROM
THE FRONTAL INFLUENCE. THEREFORE...EXPECT SCATTERED LIGHT
RAIN/DRIZZLE IN BETWEEN THAT SHOULD BE LESS ORGANIZED THAN THESE TWO
AREAS.
THE SURFACE LOW IN IOWA CONTINUES TO DEEPEN AND PUSH NE TO NORTHERN
LAKE MICHIGAN THIS MORNING. THE BETTER UPPER DYNAMICS WITH THE
FRONT ARE WITH THE SHORTWAVE MOVING THROUGH IOWA...AND THIS HEADS
NORTHWEST OF OUR AREA TODAY AS WELL. ENOUGH FRONTAL CONVERGENCE
EXISTS TO CARRY A LOW POP RAIN MENTION THROUGH THE MORNING THOUGH
MANY AREAS STAY DRY. THE BETTER MID LEVEL FORCING/FRONTOGENESIS
ARRIVES WITH THE FRONT THIS AFTERNOON BUT MOISTURE IS
LACKING...THEREFORE EXPECT A LARGELY DRY AFTERNOON EXCEPT IN NW
INDIANA AND EASTERN PORTIONS OF ILLINOIS. WITH A STRENGTHENING
UPPER JET OVERHEAD...EXPECT BREEZY SOUTHWEST WINDS AHEAD OF THE
FRONT...THEN GUSTY WEST WINDS BEHIND IT. AFTER A PLEASANT WARM UP
THE LAST FEW DAYS...THIS FRONT DOES HAVE SOME KICK TO IT...AND
WHILE THE COLD AIR DOES NOT NECESSARILY COME SCREAMING IN...DO
EXPECT A RETURN TO REALITY AND MORE SEASONAL CONDITIONS.
THE COLD FRONT WILL BE THROUGH TONIGHT. ANY LINGERING PRECIP IN OUR
FAR SE COUNTIES OF NW INDIANA MAY SEE A LIGHT RAIN/SNOW MIX BEFORE
PRECIP ENDS. OTHERWISE HIGH PRESSURE NOSES IN FROM THE WEST BRINGING
GRADUAL CLEARING OVERNIGHT. READINGS OVERNIGHT DROP INTO THE 20S
TO AROUND 30. SUNDAY LOOKS TO BE GENERALLY SUNNY BUT SEASONALLY
COLD AS THE MAIN UPPER LOW PASSES THROUGH SOUTHERN CANADA.
KMD
&&
.LONG TERM...
245 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
STRONGER CANADIAN HIGH PRESSURE...WILL BE KNOCKING AT OUR DOOR ON
SUNDAY NIGHT...AND WILL SEND A WEAK BACK DOOR COLD FRONT DOWN THE
LAKE. THE LEADING EDGE OF THIS SECONDARY SURGE OF COLD AIR WILL
TRIGGER A SIGNIFICANTLY COLDER STRETCH OF WEATHER TO KICK OFF THE
LAST FEW DAYS OF 2014. THERE MAY BE SOME WEAK LAKE EFFECT SNOW
SHOWERS GETTING INTO NE ILLINOIS...OTHERWISE INCREASING CLOUDS AND
COLDER. THEN AS THE TRULY ARCTIC AIR SPILLS IN MONDAY NIGHT...WE MAY
SEE SOME SNOW SHOWERS ALONG THE BAROCLINIC ZONE. MOISTURE IS NOT
IMPRESSIVE WITH THE FRONT...BUT THE COMBINED NE FLOW OFF THE LAKE
WITH MORE SIGNIFICANT INVERSION HEIGHTS AND MUCH COLDER AIR MAY
ALLOW FOR LAKE ENHANCEMENT AND SOME BETTER ACCUMULATION POTENTIAL.
THEN THE CHILL ENSUES FOR SEVERAL DAYS OF HIGHS ON EITHER SIDE OF 20
AND LOWS IN THE SINGLE DIGITS AND TEENS AS WE REMAIN IN NW FLOW. THE
UPSIDE...LIKELY SOME MORE SUN TO ENJOY TO END THE YEAR...AS ANY
SHORTWAVE ENERGY ROTATING THROUGH FROM THE CANADIAN VORTEX WILL
EITHER REMAIN NORTH OR GENERALLY BE WEAK AS THE ONE THAT COMES
THROUGH TUESDAY NIGHT. SOME MODIFICATION TO THE COLD AIR MASS
ARRIVES ON NEW YEARS DAY AND MORE SO FRIDAY AS WE RETURN TO
SOUTHERLY FLOW. AS THIS OCCURS...WILL HAVE TO WATCH IF LOW
PRESSURE THAT CLOSES OFF OVER CALIFORNIA EARLIER IN THE WEEK
PHASES WITH THE NORTHERN STREAM LOW OR REMAINS FARTHER SOUTH AS
THIS WILL HAVE IMPLICATIONS FOR ANY PRECIPITATION CHANCES TOWARD
WEEKS END.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WEST WINDS GUSTING UP TO 30 KT THROUGH THE AFTN.
* MVFR CIGS PERSISTING THROUGH THE EVENING.
JEE
//DISCUSSION...UPDATED 18Z...
THE COLD FRONT EXTENDS FROM PWK THROUGH FORD COUNTY IL AND IT WILL
CONTINUE EAST WITH 30KT GUSTS ALONG THE FRONT. SCATTERED LIGHT
SHOWERS ARE ALONG THE FRONT AND STILL NOT EXPECTING ANY
SIGNIFICANT IMPACT FROM THEM AS THEY QUICKLY SHIFT EAST OF THE
TERMINALS. IFR CIGS LIFT TO MVFR BEHIND THE FRONT AS WELL.
VFR CONDITIONS EXTEND FROM CENTRAL MN THROUGH NE AND EXPECTING
CIGS TO SCATTER OUT OVERNIGHT. HIGH PRESSURE SPREADS IN AND NW
WINDS DIMINISH TO LESS THAN 20 KT OVERNIGHT. VERY WEAK
WINDS...LESS THAN 5 KT...VARY FROM WEST OR SOUTHWEST OVER RFD
TOMORROW TO NORTHWEST TO NORTH OVER THE EASTERN TERMINALS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIG TRENDS...MEDIUM CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1038 AM CST Sat Dec 27 2014
.UPDATE...
ISSUED AT 1033 AM CST SAT DEC 27 2014
Weak cold front making its way through the state this morning and
has just passed over I-55 according to the depiction on radar and
the wind shift to more westerly in the obs. Cooler temps on the way
and a non-diurnal trend anticipated for locations behind the
front. Some minor precip along the boundary, but majority of radar
returns post-frontal not producing much in the way of measurable precip,
with the vast majority being drizzle. Only a few obs even picking
up on that. Not going to update the pops too much as the better
chances for rain remain in the southeast for the rest of the day.
Some small updates here and there, but nothing large scale. Will
reissue the zones only to refresh the morning wording closer to
noon.
&&
.SHORT TERM...(Today)
ISSUED AT 324 AM CST SAT DEC 27 2014
08z/2am surface analysis shows 1013mb low just north of KMLI, with
frontal boundary extending southwestward into Texas. Airmass ahead
of the front was initially quite dry as evidenced by the 00z KILX
upper air sounding: however, shallow low-level moisture has been on
the increase throughout the night. Surface dewpoints have reached
the middle 40s across central Illinois, while a plume of 50s
dewpoints is noted further upstream pushing into Arkansas. LAPS
soundings show this increasing moisture, with most local profiles
now saturated below 700mb. As low pressure tracks further
northeastward into Wisconsin, it will pull the cold front into the
area later this morning, then to the Indiana border by mid to late
afternoon. Continued moisture pooling along/ahead of the front
will result in increasingly deep moisture profiles, particularly
across the E/SE CWA this afternoon. HRRR suggests only scattered
light showers across much of the area this morning, then shows
more widespread precipitation developing along/east of I-57 this
afternoon. Think this solution makes sense as front gradually taps
into increasing amounts of Gulf moisture as it moves further east.
As a result, will carry chance PoPs across the western half of the
CWA throughout the day, with chance PoPs increasing to likely
across the E/SE this afternoon. With cold front passing through
the area, high temperatures will be achieved this morning,
followed by brisk westerly winds and falling temperatures later in
the day. Due to very mild current temps, have generally gone 2-4
degrees above MAV guidance numbers. End result will be highs in
the upper 40s and lower 50s, with temps dropping into the 30s
along/west of I-55 during the afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 324 AM CST SAT DEC 27 2014
Cold front will slowly push eastward into the Ohio River Valley
tonight, with clouds and showers lingering across the E/SE through
at least the evening hours. NAM is fastest with the departure of
the precip, while GFS tends to keep it around through the entire
night. Based on slow forward movement of the front, have trended
toward the slower GFS. As a result, will maintain low chance PoPs
along/south of I-70 through the overnight hours. As temperatures
slowly fall into the lower to middle 30s across this area, any
lingering rain showers may mix with or change to light snow late.
Further northwest, skies will clear across the Illinois River
Valley, allowing lows to bottom out in the lower to middle 20s.
Sunshine and seasonably cool temps in the 30s will prevail Sunday
into Monday, before a surge of cold air arrives next week. Models
have been consistently showing strong 1050mb high building southward
out of western Canada into the central CONUS by Tuesday/Wednesday.
Weak synoptic lift along the leading edge of the cold air may be
enough to trigger a few flurries across the area Monday night, but
the main story will be the colder temps. High temps will remain in
the 20s Tuesday/Wednesday, while overnight lows dip into the single
digits and teens. After that, Canadian high pressure will gradually
slide east of the region, allowing a southern stream system to
approach by the end of the week. Model solutions vary with this
feature, so forecast confidence remains low at this point. ECMWF
aggressively brings precip northward into south-central Illinois as
early as Thursday night, while the GFS is about 12-18 hours
slower. Meanwhile, the GEM suggests the system may remain largely
southeast of the area across the Ohio River Valley. Given the
uncertainties, have opted to go with a dry forecast Thursday night,
and to slow precip onset on Friday. Have trimmed Friday PoPs to
just slight chance, with higher precip chances arriving Friday night
into Saturday. Think slower/colder is the way to go, especially
given the Canadian airmass that will initially be in place. End
result will be a chance of snow or a rain/snow mix mainly Friday
night into Saturday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 533 AM CST SAT DEC 27 2014
Widespread IFR conditions (mainly CIGS) can be expected across the
central Illinois terminals to start the 12Z TAF valid time. These
low CIGS are occurring in an unseasonably warm/moist airmass ahead
of an approaching cold front. CIGS should quickly rise to MVFR
with the passage of a cold front later this morning or early this
afternoon. The passage of this front will have winds swinging
around from the southwest to the west. Expect low clouds to
scatter out this evening as drier air filters into the region
behind the front. This drier air will also be accompanied by a
wind shift to the northwest.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
544 AM CST SAT DEC 27 2014
.SHORT TERM...
245 AM CST
THROUGH SUNDAY...
WE ARE LIVING ON BORROWED TIME WITH 850 MB TEMPS SITTING ABOVE
ZERO...BUT THAT WILL BE A THING OF THE PAST COME THIS AFTERNOON. BUT
FIRST OFF...LIGHT RAIN/DRIZZLE IN EAST CENTRAL ILLINOIS AND INTO NW
INDY IS ASSOCIATED WITH THE SLIGHTLY BETTER ISENTROPIC LIFT/MOISTURE
ADVECTION. THIS WILL DRIFT OFF TO THE EAST THIS MORNING AND WILL
GRAZE OUR SE COUNTIES. MEANWHILE A SECOND AREA OF LIGHT RAIN
CONTINUES OVER NORTHWEST/NORTH CENTRAL ILLINOIS CLOSER TO THE NORTHWARD
MOVING LOW AND EASTWARD ADVANCING COLD FRONT. MUCH OF OUR AREA FINDS
ITSELF IN AN AREA OF WEAKER ISENTROPIC LIFT AND A BIT REMOVED FROM
THE FRONTAL INFLUENCE. THEREFORE...EXPECT SCATTERED LIGHT
RAIN/DRIZZLE IN BETWEEN THAT SHOULD BE LESS ORGANIZED THAN THESE TWO
AREAS.
THE SURFACE LOW IN IOWA CONTINUES TO DEEPEN AND PUSH NE TO NORTHERN
LAKE MICHIGAN THIS MORNING. THE BETTER UPPER DYNAMICS WITH THE
FRONT ARE WITH THE SHORTWAVE MOVING THROUGH IOWA...AND THIS HEADS
NORTHWEST OF OUR AREA TODAY AS WELL. ENOUGH FRONTAL CONVERGENCE
EXISTS TO CARRY A LOW POP RAIN MENTION THROUGH THE MORNING THOUGH
MANY AREAS STAY DRY. THE BETTER MID LEVEL FORCING/FRONTOGENESIS
ARRIVES WITH THE FRONT THIS AFTERNOON BUT MOISTURE IS
LACKING...THEREFORE EXPECT A LARGELY DRY AFTERNOON EXCEPT IN NW
INDIANA AND EASTERN PORTIONS OF ILLINOIS. WITH A STRENGTHENING
UPPER JET OVERHEAD...EXPECT BREEZY SOUTHWEST WINDS AHEAD OF THE
FRONT...THEN GUSTY WEST WINDS BEHIND IT. AFTER A PLEASANT WARM UP
THE LAST FEW DAYS...THIS FRONT DOES HAVE SOME KICK TO IT...AND
WHILE THE COLD AIR DOES NOT NECESSARILY COME SCREAMING IN...DO
EXPECT A RETURN TO REALITY AND MORE SEASONAL CONDITIONS.
THE COLD FRONT WILL BE THROUGH TONIGHT. ANY LINGERING PRECIP IN OUR
FAR SE COUNTIES OF NW INDIANA MAY SEE A LIGHT RAIN/SNOW MIX BEFORE
PRECIP ENDS. OTHERWISE HIGH PRESSURE NOSES IN FROM THE WEST BRINGING
GRADUAL CLEARING OVERNIGHT. READINGS OVERNIGHT DROP INTO THE 20S
TO AROUND 30. SUNDAY LOOKS TO BE GENERALLY SUNNY BUT SEASONALLY
COLD AS THE MAIN UPPER LOW PASSES THROUGH SOUTHERN CANADA.
KMD
&&
.LONG TERM...
245 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
STRONGER CANADIAN HIGH PRESSURE...WILL BE KNOCKING AT OUR DOOR ON
SUNDAY NIGHT...AND WILL SEND A WEAK BACK DOOR COLD FRONT DOWN THE
LAKE. THE LEADING EDGE OF THIS SECONDARY SURGE OF COLD AIR WILL
TRIGGER A SIGNIFICANTLY COLDER STRETCH OF WEATHER TO KICK OFF THE
LAST FEW DAYS OF 2014. THERE MAY BE SOME WEAK LAKE EFFECT SNOW
SHOWERS GETTING INTO NE ILLINOIS...OTHERWISE INCREASING CLOUDS AND
COLDER. THEN AS THE TRULY ARCTIC AIR SPILLS IN MONDAY NIGHT...WE MAY
SEE SOME SNOW SHOWERS ALONG THE BAROCLINIC ZONE. MOISTURE IS NOT
IMPRESSIVE WITH THE FRONT...BUT THE COMBINED NE FLOW OFF THE LAKE
WITH MORE SIGNIFICANT INVERSION HEIGHTS AND MUCH COLDER AIR MAY
ALLOW FOR LAKE ENHANCEMENT AND SOME BETTER ACCUMULATION POTENTIAL.
THEN THE CHILL ENSUES FOR SEVERAL DAYS OF HIGHS ON EITHER SIDE OF 20
AND LOWS IN THE SINGLE DIGITS AND TEENS AS WE REMAIN IN NW FLOW. THE
UPSIDE...LIKELY SOME MORE SUN TO ENJOY TO END THE YEAR...AS ANY
SHORTWAVE ENERGY ROTATING THROUGH FROM THE CANADIAN VORTEX WILL
EITHER REMAIN NORTH OR GENERALLY BE WEAK AS THE ONE THAT COMES
THROUGH TUESDAY NIGHT. SOME MODIFICATION TO THE COLD AIR MASS
ARRIVES ON NEW YEARS DAY AND MORE SO FRIDAY AS WE RETURN TO
SOUTHERLY FLOW. AS THIS OCCURS...WILL HAVE TO WATCH IF LOW
PRESSURE THAT CLOSES OFF OVER CALIFORNIA EARLIER IN THE WEEK
PHASES WITH THE NORTHERN STREAM LOW OR REMAINS FARTHER SOUTH AS
THIS WILL HAVE IMPLICATIONS FOR ANY PRECIPITATION CHANCES TOWARD
WEEKS END.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* IFR CIGS LIFT SLIGHTS TO MVFR TODAY AND POTENTIALLY LINGER
TONIGHT
* BRIEF SHRA ALONG THE FRONT LATE THIS MORNING
* STRONG/GUSTY WEST WINDS LATE THIS MORNING THROUGH THIS AFTERNOON
IZZI
//DISCUSSION...UPDATED 12Z...
COLD FRONT WILL SWEEP ACROSS THE TERMINALS MID-LATE MORNING
PROBABLY ACCOMPANIED BY A BAND OF SHRA ALONG THE FRONT AND QUICKLY
FOLLOWED BY STRONG/GUSTY WEST WINDS. COULD BE A BRIEF PERIOD OF
GUSTS AROUND 30KT BEFORE PREVAILING GUSTS TEND TO SETTLE MORE IN
THE MID-UPPER 20 KNOT RANGE. IFR CIGS THIS MORNING COULD LIFT
SLIGHTLY TO LOW END MVFR PRIOR TO THE FRONT MOVING THROUGH BUT
LIKELY LIFT TO MVFR IN THE WAKE OF THE FRONT. MVFR CIGS WILL
PROBABLY LINGER INTO AT LEAST THIS EVENING BUT COULD POTENTIALLY
CLEAR OUT LATER TONIGHT...BUT CONFIDENCE IN LOW IN CLEARING TIME
SO HELD ON TO MVFR CIGS FOR NOW.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN CIGS TODAY...LOW CONFIDENCE TONIGHT
* MEDIUM CONFIDENCE IN SHOWERS
* HIGH CONFIDENCE IN WINDS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
541 AM CST Sat Dec 27 2014
.SHORT TERM...(Today)
ISSUED AT 324 AM CST SAT DEC 27 2014
08z/2am surface analysis shows 1013mb low just north of KMLI, with
frontal boundary extending southwestward into Texas. Airmass ahead
of the front was initially quite dry as evidenced by the 00z KILX
upper air sounding: however, shallow low-level moisture has been on
the increase throughout the night. Surface dewpoints have reached
the middle 40s across central Illinois, while a plume of 50s
dewpoints is noted further upstream pushing into Arkansas. LAPS
soundings show this increasing moisture, with most local profiles
now saturated below 700mb. As low pressure tracks further
northeastward into Wisconsin, it will pull the cold front into the
area later this morning, then to the Indiana border by mid to late
afternoon. Continued moisture pooling along/ahead of the front
will result in increasingly deep moisture profiles, particularly
across the E/SE CWA this afternoon. HRRR suggests only scattered
light showers across much of the area this morning, then shows
more widespread precipitation developing along/east of I-57 this
afternoon. Think this solution makes sense as front gradually taps
into increasing amounts of Gulf moisture as it moves further east.
As a result, will carry chance PoPs across the western half of the
CWA throughout the day, with chance PoPs increasing to likely
across the E/SE this afternoon. With cold front passing through
the area, high temperatures will be achieved this morning,
followed by brisk westerly winds and falling temperatures later in
the day. Due to very mild current temps, have generally gone 2-4
degrees above MAV guidance numbers. End result will be highs in
the upper 40s and lower 50s, with temps dropping into the 30s
along/west of I-55 during the afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 324 AM CST SAT DEC 27 2014
Cold front will slowly push eastward into the Ohio River Valley
tonight, with clouds and showers lingering across the E/SE through
at least the evening hours. NAM is fastest with the departure of
the precip, while GFS tends to keep it around through the entire
night. Based on slow forward movement of the front, have trended
toward the slower GFS. As a result, will maintain low chance PoPs
along/south of I-70 through the overnight hours. As temperatures
slowly fall into the lower to middle 30s across this area, any
lingering rain showers may mix with or change to light snow late.
Further northwest, skies will clear across the Illinois River
Valley, allowing lows to bottom out in the lower to middle 20s.
Sunshine and seasonably cool temps in the 30s will prevail Sunday
into Monday, before a surge of cold air arrives next week. Models
have been consistently showing strong 1050mb high building southward
out of western Canada into the central CONUS by Tuesday/Wednesday.
Weak synoptic lift along the leading edge of the cold air may be
enough to trigger a few flurries across the area Monday night, but
the main story will be the colder temps. High temps will remain in
the 20s Tuesday/Wednesday, while overnight lows dip into the single
digits and teens. After that, Canadian high pressure will gradually
slide east of the region, allowing a southern stream system to
approach by the end of the week. Model solutions vary with this
feature, so forecast confidence remains low at this point. ECMWF
aggressively brings precip northward into south-central Illinois as
early as Thursday night, while the GFS is about 12-18 hours
slower. Meanwhile, the GEM suggests the system may remain largely
southeast of the area across the Ohio River Valley. Given the
uncertainties, have opted to go with a dry forecast Thursday night,
and to slow precip onset on Friday. Have trimmed Friday PoPs to
just slight chance, with higher precip chances arriving Friday night
into Saturday. Think slower/colder is the way to go, especially
given the Canadian airmass that will initially be in place. End
result will be a chance of snow or a rain/snow mix mainly Friday
night into Saturday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 533 AM CST SAT DEC 27 2014
Widespread IFR conditions (mainly CIGS) can be expected across the
central Illinois terminals to start the 12Z TAF valid time. These
low CIGS are occurring in an unseasonably warm/moist airmass ahead
of an approaching cold front. CIGS should quickly rise to MVFR
with the passage of a cold front later this morning or early this
afternoon. The passage of this front will have winds swinging
around from the southwest to the west. Expect low clouds to
scatter out this evening as drier air filters into the region
behind the front. This drier air will also be accompanied by a
wind shift to the northwest.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
159 AM CST SAT DEC 27 2014
.SHORT TERM...
238 PM CST
THROUGH SUNDAY...
AN UPPER LEVEL RIDGE AXIS STRETCHES FROM CUBA UP THE ATLANTIC COAST
WITH THE SURFACE HIGH OVER THE SOUTHEAST U.S. THE UPPER LEVEL RIDGE
SHIFTS VERY LITTLE THROUGH SATURDAY. A NARROW SURFACE TROUGH EXTENDS
FROM TEXAS THROUGH THE UPPER PENINSULA OF MICHIGAN THIS AFTERNOON. A
CLOSED LOW WILL FORM OVER THE MID MISSISSIPPI VALLEY TONIGHT AND
MOVE OVER NORTHERN IL LATE TONIGHT/EARLY SATURDAY MORNING BEFORE
MAKING IT TO QUEBEC SATURDAY EVENING. WEAK HIGH PRESSURE THEN
SPREADS OVER THE CWA SUNDAY.
TEMPERATURES CONTINUE TO CLIMB INTO THE UPPER 40S TO LOWER 50S THIS
AFTERNOON WITH THE MAJORITY OF THE CWA RECEIVING AMPLE SUNSHINE.
CLOUD COVER WILL INCREASE THIS EVENING AND OVERNIGHT AS THE LOW
TAKES SHAPE AND MOVES IN. WITH THE SURFACE LOW PASSING RIGHT
OVERHEAD...THINKING FOG OR DRIZZLE IS PROBABLE ESPECIALLY WEST OF A
MCHENRY TO JOLIET LINE. ONLY HAVE PATCHY FOG IN THE FORECAST...BUT
COULD SEE VSBYS IN SOME AREAS DROP TO AROUND OR LESS THAN ONE MILE
DUE TO FOG OR DRIZZLE.
RAIN/DRIZZLE MOVES IN FROM SOUTHWEST TO NORTHEAST LATE THIS
EVENING...AND LATEST RAP AND HRRR GUIDANCE INDICATE THE PRECIP WILL
MOVE IN QUICKER THAN PREVIOUSLY THOUGHT. IT LOOKS LIKE A GOOD HIGH
POP/LOW QPF SITUATION. HAVE AN INCREASING POP TREND FROM MIDNIGHT
THROUGH THE EARLY MORNING HOURS AS THE LOW MOVES OVERHEAD. LIGHT
RAIN SHIFTS EAST SATURDAY AFTERNOON AS THE LOW CONTINUES NORTHEAST.
GUSTY WEST WINDS ARE EXPECTED TOMORROW WITH GUSTS AROUND 30 MPH IN
THE AFTERNOON. TEMPERATURES WILL ALSO BE FALLING FROM THE LATE
MORNING HOURS ON BEHIND THE LOWS COLD FRONT. HOWEVER AREAS ALONG AND
EAST OF I-55 WILL SEE HIGH TEMPS IN THE MID 40S TO AROUND 50. TEMPS
FALL INTO THE 20S SATURDAY NIGHT.
LIGHT WINDS SHIFT TO OUT OF THE NORTHWEST OR NORTH SUNDAY WITH DRY
CONDITIONS EXPECTED. THE COOLER AIR MASS WILL KEEP HIGH TEMPS IN THE
30S...BUT WE SHOULD SEE SOME SUNSHINE.
JEE
&&
.LONG TERM...
238 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW WILL SHIFT EAST OVER NORTHERN QUEBEC
SUNDAY...AND A VORTICITY STREAMER ASSOCIATED WITH THE LOW PUSHES
SOUTH THROUGH THE REGION MONDAY. ANOTHER TROUGH AXIS SWINGS THROUGH
WEDNESDAY. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS OVER THE
REGION SUNDAY NIGHT. A COLD FRONT COINCIDED WITH THE VORT STREAMER
PUSHES THROUGH THE REGION MONDAY. ARCTIC HIGH PRESSURE FOLLOWS THE
COLD FRONT...AND FINALLY SHIFTS SOUTH TO THE GULF STATES THURSDAY.
CLOUDS INCREASE SUNDAY NIGHT AHEAD OF THE COLD FRONT WITH LOW TEMPS
IN THE 20S. FLURRIES AND LIGHT SNOW ARE EXPECTED ALONG THE COLD
FRONT AS MODELS CONTINUE TO FEATURE A LITTLE QPF. COLD AIR MASSES
SUCH AS THIS ONE CAN USUALLY SQUEEZE OUT ANY MOISTURE LINGERING IN
THE AIR SO HAVE HIGHER POPS WHERE MODELS FEATURED QPF AND FLURRIES
ACROSS THE REST OF THE CWA. NOT EXPECTING MUCH SNOW ACCUMULATION IF
ANY AT ALL. NORTH WINDS DOWN THE LAKE MAY RESULT IN LAKE EFFECT
SNOW OVER NW INDIANA MONDAY NIGHT INTO TUESDAY. COULD SEE A COUPLE
TENTHS OF AN INCH OF SNOW.
THE BIGGER IMPACT WILL BE TEMPERATURES. HIGH TEMPS WILL BE IN THE
LOWER 30S MONDAY THEN ONLY IN THE UPPER TEENS TO MID 20S TUESDAY.
LOW TEMPS TUESDAY WILL BE VARY FROM THE SINGLE DIGITS OVER NORTH
CENTRAL IL TO AROUND 10 DEGREES OVER NORTHWEST INDIANA. BRISK NW
WINDS WILL CREATE BELOW ZERO WIND CHILLS TUESDAY NIGHT INTO WEDNESDAY
MORNING. THE WHOLE CWA FEELS THE CHILL WEDNESDAY WITH HIGH TEMPS
AROUND 20 DEGREES BUT GUSTY WEST WINDS WILL MAKE IT FEEL LIKE IT IS
IN THE SINGLE DIGITS.
THE CENTER OF THE HIGH SHIFTS SOUTH OF THE REGION THURSDAY ALLOWING
TEMPS TO WARM SLIGHTLY INTO THE UPPER 20S THURSDAY. LONG RANGE
GUIDANCE THEN FEATURES A LOW PRESSURE SYSTEM MOVING UP THE OHIO
RIVER VALLEY LATE NEXT WEEK. GUIDANCE HAS THE SYSTEM BRINGING US
SNOW OVER THE WEEKEND...SO WILL KEEP AN EYE ON THIS SYSTEM.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS DEVELOPING OVERNIGHT POSSIBLY DROPPING TO IFR FOR A
TIME LATE TONIGHT/SATURDAY MORNING
* STRONG WEST WINDS LIKELY SATURDAY BEHIND COLD FRONT
* LINGERING MVFR CIGS POSSIBLE SAT AFTERNOON AND POSSIBLY SAT NIGHT
IZZI
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER EASTERN IOWA WILL TRACK NORTHEAST INTO
WISCONSIN. NOT SEEING A TON OF SUPPORT FOR IFR CIGS AND DRIZZLE
OVERNIGHT WITH NEAREST IFR CIGS STILL IN SOUTHERN MISSOURI...BUT
WAS RELUCTANT TO TOTALLY REMOVE IT GIVEN PRETTY STRONG SIGNAL IN
GUIDANCE FOR A TIME LATE TONIGHT/SAT MORNING. STILL COULD BE A
SHOWER OR TWO AROUND OVERNIGHT...BUT CHANCES LOOK LOW WITH MUCH IF
NOT ALL THE NIGHT NOW LOOKING TO BE DRY. COLD FRONT WILL SWEEP
ACROSS RFD MID-LATE MORNING AND CLEAR CHICAGO TERMINALS MIDDAY
WITH STRONG/GUSTY WESTERLY WINDS DEVELOPING IN THE WAKE OF THE
FRONT. COULD SEE A COUPLE GUSTS OVER 30KT BUT PREVAILING GUSTS IN
THE 23-28KT RANGE APPEARS PRETTY LIKELY UNTIL WINDS BEGIN TO
SUBSIDE AT SUNSET. MVFR CIGS WILL PROBABLY LINGER THROUGH THE
AFTERNOON AND PROBABLY INTO THE EVENING. COULD SEE MVFR CIGS BEGIN
TO SCATTER OUT AFTER MIDNIGHT SAT NIGHT AS LOW LEVEL FLOW BECOMES
MORE ANTICYCLONIC AND MODELS SUGGEST CONSIDERABLE DRYING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE IN CIGS
* MEDIUM-HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR. LIGHT W WINDS BECOMING NNE LATE.
MONDAY...SCHC -SHSN. MVFR PSBL. N TO NE WINDS.
TUESDAY...VFR. BREEZY NW WINDS.
WEDNESDAY AND THURSDAY...VFR. BREEZY SW WINDS AT TIMES.
MDB
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1140 PM CST FRI DEC 26 2014
.SHORT TERM...
238 PM CST
THROUGH SUNDAY...
AN UPPER LEVEL RIDGE AXIS STRETCHES FROM CUBA UP THE ATLANTIC COAST
WITH THE SURFACE HIGH OVER THE SOUTHEAST U.S. THE UPPER LEVEL RIDGE
SHIFTS VERY LITTLE THROUGH SATURDAY. A NARROW SURFACE TROUGH EXTENDS
FROM TEXAS THROUGH THE UPPER PENINSULA OF MICHIGAN THIS AFTERNOON. A
CLOSED LOW WILL FORM OVER THE MID MISSISSIPPI VALLEY TONIGHT AND
MOVE OVER NORTHERN IL LATE TONIGHT/EARLY SATURDAY MORNING BEFORE
MAKING IT TO QUEBEC SATURDAY EVENING. WEAK HIGH PRESSURE THEN
SPREADS OVER THE CWA SUNDAY.
TEMPERATURES CONTINUE TO CLIMB INTO THE UPPER 40S TO LOWER 50S THIS
AFTERNOON WITH THE MAJORITY OF THE CWA RECEIVING AMPLE SUNSHINE.
CLOUD COVER WILL INCREASE THIS EVENING AND OVERNIGHT AS THE LOW
TAKES SHAPE AND MOVES IN. WITH THE SURFACE LOW PASSING RIGHT
OVERHEAD...THINKING FOG OR DRIZZLE IS PROBABLE ESPECIALLY WEST OF A
MCHENRY TO JOLIET LINE. ONLY HAVE PATCHY FOG IN THE FORECAST...BUT
COULD SEE VSBYS IN SOME AREAS DROP TO AROUND OR LESS THAN ONE MILE
DUE TO FOG OR DRIZZLE.
RAIN/DRIZZLE MOVES IN FROM SOUTHWEST TO NORTHEAST LATE THIS
EVENING...AND LATEST RAP AND HRRR GUIDANCE INDICATE THE PRECIP WILL
MOVE IN QUICKER THAN PREVIOUSLY THOUGHT. IT LOOKS LIKE A GOOD HIGH
POP/LOW QPF SITUATION. HAVE AN INCREASING POP TREND FROM MIDNIGHT
THROUGH THE EARLY MORNING HOURS AS THE LOW MOVES OVERHEAD. LIGHT
RAIN SHIFTS EAST SATURDAY AFTERNOON AS THE LOW CONTINUES NORTHEAST.
GUSTY WEST WINDS ARE EXPECTED TOMORROW WITH GUSTS AROUND 30 MPH IN
THE AFTERNOON. TEMPERATURES WILL ALSO BE FALLING FROM THE LATE
MORNING HOURS ON BEHIND THE LOWS COLD FRONT. HOWEVER AREAS ALONG AND
EAST OF I-55 WILL SEE HIGH TEMPS IN THE MID 40S TO AROUND 50. TEMPS
FALL INTO THE 20S SATURDAY NIGHT.
LIGHT WINDS SHIFT TO OUT OF THE NORTHWEST OR NORTH SUNDAY WITH DRY
CONDITIONS EXPECTED. THE COOLER AIR MASS WILL KEEP HIGH TEMPS IN THE
30S...BUT WE SHOULD SEE SOME SUNSHINE.
JEE
&&
.LONG TERM...
238 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW WILL SHIFT EAST OVER NORTHERN QUEBEC
SUNDAY...AND A VORTICITY STREAMER ASSOCIATED WITH THE LOW PUSHES
SOUTH THROUGH THE REGION MONDAY. ANOTHER TROUGH AXIS SWINGS THROUGH
WEDNESDAY. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS OVER THE
REGION SUNDAY NIGHT. A COLD FRONT COINCIDED WITH THE VORT STREAMER
PUSHES THROUGH THE REGION MONDAY. ARCTIC HIGH PRESSURE FOLLOWS THE
COLD FRONT...AND FINALLY SHIFTS SOUTH TO THE GULF STATES THURSDAY.
CLOUDS INCREASE SUNDAY NIGHT AHEAD OF THE COLD FRONT WITH LOW TEMPS
IN THE 20S. FLURRIES AND LIGHT SNOW ARE EXPECTED ALONG THE COLD
FRONT AS MODELS CONTINUE TO FEATURE A LITTLE QPF. COLD AIR MASSES
SUCH AS THIS ONE CAN USUALLY SQUEEZE OUT ANY MOISTURE LINGERING IN
THE AIR SO HAVE HIGHER POPS WHERE MODELS FEATURED QPF AND FLURRIES
ACROSS THE REST OF THE CWA. NOT EXPECTING MUCH SNOW ACCUMULATION IF
ANY AT ALL. NORTH WINDS DOWN THE LAKE MAY RESULT IN LAKE EFFECT
SNOW OVER NW INDIANA MONDAY NIGHT INTO TUESDAY. COULD SEE A COUPLE
TENTHS OF AN INCH OF SNOW.
THE BIGGER IMPACT WILL BE TEMPERATURES. HIGH TEMPS WILL BE IN THE
LOWER 30S MONDAY THEN ONLY IN THE UPPER TEENS TO MID 20S TUESDAY.
LOW TEMPS TUESDAY WILL BE VARY FROM THE SINGLE DIGITS OVER NORTH
CENTRAL IL TO AROUND 10 DEGREES OVER NORTHWEST INDIANA. BRISK NW
WINDS WILL CREATE BELOW ZERO WIND CHILLS TUESDAY NIGHT INTO WEDNESDAY
MORNING. THE WHOLE CWA FEELS THE CHILL WEDNESDAY WITH HIGH TEMPS
AROUND 20 DEGREES BUT GUSTY WEST WINDS WILL MAKE IT FEEL LIKE IT IS
IN THE SINGLE DIGITS.
THE CENTER OF THE HIGH SHIFTS SOUTH OF THE REGION THURSDAY ALLOWING
TEMPS TO WARM SLIGHTLY INTO THE UPPER 20S THURSDAY. LONG RANGE
GUIDANCE THEN FEATURES A LOW PRESSURE SYSTEM MOVING UP THE OHIO
RIVER VALLEY LATE NEXT WEEK. GUIDANCE HAS THE SYSTEM BRINGING US
SNOW OVER THE WEEKEND...SO WILL KEEP AN EYE ON THIS SYSTEM.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS DEVELOPING OVERNIGHT POSSIBLY DROPPING TO IFR FOR A
TIME LATE TONIGHT/SATURDAY MORNING
* STRONG WEST WINDS LIKELY SATURDAY BEHIND COLD FRONT
* LINGERING MVFR CIGS POSSIBLE SAT AFTERNOON AND POSSIBLY SAT NIGHT
IZZI
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER EASTERN IOWA WILL TRACK NORTHEAST INTO
WISCONSIN. NOT SEEING A TON OF SUPPORT FOR IFR CIGS AND DRIZZLE
OVERNIGHT WITH NEAREST IFR CIGS STILL IN SOUTHERN MISSOURI...BUT
WAS RELUCTANT TO TOTALLY REMOVE IT GIVEN PRETTY STRONG SIGNAL IN
GUIDANCE FOR A TIME LATE TONIGHT/SAT MORNING. STILL COULD BE A
SHOWER OR TWO AROUND OVERNIGHT...BUT CHANCES LOOK LOW WITH MUCH IF
NOT ALL THE NIGHT NOW LOOKING TO BE DRY. COLD FRONT WILL SWEEP
ACROSS RFD MID-LATE MORNING AND CLEAR CHICAGO TERMINALS MIDDAY
WITH STRONG/GUSTY WESTERLY WINDS DEVELOPING IN THE WAKE OF THE
FRONT. COULD SEE A COUPLE GUSTS OVER 30KT BUT PREVAILING GUSTS IN
THE 23-28KT RANGE APPEARS PRETTY LIKELY UNTIL WINDS BEGIN TO
SUBSIDE AT SUNSET. MVFR CIGS WILL PROBABLY LINGER THROUGH THE
AFTERNOON AND PROBABLY INTO THE EVENING. COULD SEE MVFR CIGS BEGIN
TO SCATTER OUT AFTER MIDNIGHT SAT NIGHT AS LOW LEVEL FLOW BECOMES
MORE ANTICYCLONIC AND MODELS SUGGEST CONSIDERABLE DRYING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE IN CIGS
* MEDIUM-HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR. LIGHT W WINDS BECOMING NNE LATE.
MONDAY...SCHC -SHSN. MVFR PSBL. N TO NE WINDS.
TUESDAY...VFR. BREEZY NW WINDS.
WEDNESDAY AND THURSDAY...VFR. BREEZY SW WINDS AT TIMES.
MDB
&&
.MARINE...
324 PM CST
A TROUGH OF LOW PRESSURE MOVING ACROSS THE REGION IS HELPING TO
PROVIDE SIGNIFICANT DIFFERENCES WITH WIND SPEED AND DIRECTION
ACROSS THE ENTIRE LAKE THIS AFTERNOON...AND EXPECT THESE
DIFFERENCES TO REMAIN IN PLACE TONIGHT INTO SATURDAY MORNING.
WHILE SOUTHERLY FLOW REMAINS IN PLACE OVER THE SOUTHERN HALF OF
THE LAKE...SOUTHERLY WINDS OVER THE NORTHERN HALF ARE ALREADY
SLOWLY BECOMING MORE NORTHERLY AS THIS TROUGH MOVES ACROSS THE
LAKE. THIS TREND WILL CONTINUE OVER THE NORTHERN HALF TONIGHT WITH
MORE NORTHERLY WINDS EXPECTED LATER TONIGHT...WHILE SOUTHERLY
WINDS PERSIST OVER THE SOUTHERN HALF. NEW LOW PRESSURE WILL THEN
DEVELOP ALONG THIS TROUGH/BOUNDARY EARLY SATURDAY MORNING AND MOVE
ACROSS THE LAKE SATURDAY. EXPECT SPEEDS TO INCREASE DURING THE DAY
AS WINDS BECOME MORE WESTERLY IN THE AFTERNOON...AND THEN
NORTHWEST IN THE EVENING. EXPECT SPEEDS TO THEN DIMINISH SATURDAY
NIGHT INTO SUNDAY AS THIS LOW DEPARTS AND HIGH PRESSURE BUILDS
ACROSS THE REGION.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
332 PM EST SAT DEC 27 2014
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 PM EST SAT DEC 27 2014
A COLD FRONT WILL MOVE EAST ACROSS OUR REGION TONIGHT. A DRY
SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION
AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL
BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE
AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW
PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY.
&&
.NEAR TERM /REST OF AFTERNOON THROUGH TONIGHT/...
ISSUED AT 324 PM EST SAT DEC 27 2014
TRENDS AMONG THE MODELS REMAIN VIRTUALLY THE SAME...WITH THE EURO
AND NAM BEING MUCH MORE PROGRESSIVE THAN THE GFS AND GEM. AS
USUAL...THE SREF AND HRRR TAKE A DECENT BLEND OF THE FASTER AND
SLOWER SOLUTIONS...SO LEANED HEAVILY TOWARD THIS GUIDANCE WHEN
CREATING THE POPS FOR TONIGHT. ALSO TRIED TO WORK IN WHAT IS
CURRENTLY ON THE RADAR SCOPE WITH ONE WAVE OF LIGHT RAIN MOVING IN
FROM THE SOUTH...WHICH WILL LATER THE EXIT THE FORECAST AREA BY
00Z. WHILE THE MAIN AREA OF PRECIPITATION IS BEGINNING TO APPROACH
THE CENTRAL INDIANA AREA FROM CENTRAL ILLINOIS. THIS AREA WILL
MAKE IT/S WAY THROUGH THE BULK OF CENTRAL INDIANA FROM 00Z TO 08Z.
WITH A FEW COUNTIES TO THE SOUTHEAST COUNTIES SEEING SOME
LINGERING POPS INTO EARLY SUNDAY MORNING.
ATTENTION THEN TURNS TO PRECIP TYPE AND TIMING...BOTH OF WHICH
WILL BE TRICKY. ALL OF THE PRECIP OVER CENTRAL INDIANA WILL BE IN
THE FORM OF RAIN THROUGH THIS EVENING. COLDER AIR WILL BEGIN
WORKING INTO THE NORTHWEST COUNTIES OF THE CWA ABOUT MIDNIGHT AND
PUSH TOWARD THE I-70 CORRIDOR BY 2-3 AM. BEST CHANCE IN TERMS OF
PRECIP TYPE ARE STILL A -RA/SN MIX...CANNOT RULE OUT ANY SLEET
MIXING IN AT TIMES HOWEVER NOT WIDESPREAD ENOUGH TO HAVE THE
CONFIDENCE TO INCLUDE IT IN FORECAST AT THIS TIME. THIS MIX WILL
WORK IT/S WAY TOWARD THE E/SE EARLY SUNDAY MORNING...WHILE PRECIP
BEHIND IT BEGINS TO WIND DOWN AND DRY OUT OVER MOST OF THE
FORECAST AREA BY 12Z SUNDAY MORNING. LOWS 31-36.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 324 PM EST SAT DEC 27 2014
AS MENTIONED IN ABOVE DISCUSSION...THERE WILL LIKELY BE SOME REMNANT
MIXTURE OF -RA/SN FOR EARLY SUNDAY MORNING ACROSS SEVERAL OF THE
SOUTHEASTERN COUNTIES BEFORE THAT FRONT MOVES FARTHER FROM THE AREA
AND DRIER AND COLDER AIR FILTERS BACK INTO THE AREA. WILL CONTINUE
LOW CHANCE POPS THERE AT LEAST THROUGH 14-15Z SUNDAY MORNING.
DRY AND COOLER WEATHER WILL PERSIST ACROSS THE REGION FOR THE BETTER
HALF OF THE NEXT WEEK AS A LARGE AREA OF HIGH PRESSURE REMAINS IN
CONTROL OVER THE REGION. MODELS INDICATE HIGHS IN THE UPPER 30S
SUNDAY AND PERHAPS A DEGREE OR TWO WARMER MONDAY. LOWS WILL BE IN
THE MIDDLE TO UPPER 20S SUNDAY NIGHT AND LOWER OR MIDDLE 20S MONDAY
NIGHT AS A DRY SECONDARY COLD FRONT MOVES THROUGH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 240 PM EST SAT DEC 27 2014
MAIN FOCUS FOR THE EXTENDED PERIOD WILL BE POPS AND PRECIPITATION
TYPE STARTING FRIDAY. PRIOR TO THAT...TEMPERATURES WILL BE THE
BIGGEST ISSUE AS STRONG COLD WESTERN CANADIAN HIGH PRESSURE WILL
SETTLE ACROSS THE OHIO VALLEY TO END THE OLD YEAR AND START THE NEW
ONE.
DETERMINISTIC MODELS ARE IN DECENT AGREEMENT THAT AN UPPER LOW WILL
BE OVER NORTHEASTERN ARIZONA DURING THE EVENING OF THE FIRST DAY OF
2015. HOWEVER...THE MODELS THEN DIVERGE RAPIDLY WITH THE MUCH
QUICKER 12Z GFS BRINGING A STRONGER SURFACE SYSTEM BUT WEAK UPPER
WAVE OVER THE OHIO VALLEY FRIDAY NIGHT. MEANWHILE...THE 12Z ECMWF
HAS EVEN A WEAKER BUT MUCH SLOWER WAVE LIFT NORTHEAST TO SOUTHERN
ILLINOIS BY NEXT SATURDAY EVENING. THE EURO ALSO HAS THE MAIN
SURFACE LOW WELL SOUTHWEST OF THE 12Z GFS POSITION SATURDAY EVENING.
THE ECMWF HAS THE SURFACE LOW OVER EASTERN KENTUCKY...WHILE THE GFS
HAS IT OVER SOUTHERN QUEBEC. DESPITE ALL THESE DIFFERENCES...BOTH
MODELS START THE QPF ON FRIDAY WITH THE HEAVIEST PRECIPITATION ALONG
THE OHIO RIVER. MEANWHILE...THE EURO WAS HOLDING MORE QPF AROUND ON
SUNDAY THAN THE GFS. SO...STILL EXPECT THE PRECIPITATION TO SPREAD
NORTHEAST ACROSS THE AREA ON FRIDAY. WITH CONFIDENCE IN TIMING
LOW...WILL ACCEPT THE REGIONAL BLEND THAT KEEPS DECENT POPS AROUND
NEXT SATURDAY AS HINTED AT BY THE EURO.
REGARDING PRECIPITATION TYPE...WILL NOT MAKE MANY CHANGES WITH THE
MODEL DIFFERENCES. CONFIDENCE NOT GOOD AS TO WHERE THE RAIN/SNOW
LINE WILL BE IN SPACE AND TIME. HOWEVER...NORTHEASTERN PARTS OF THE
FORECAST AREA WILL BE MORE LIKELY TO SEE FROZEN OR MIXED
PRECIPITATION THEN THE SOUTHWESTERN ONES ON FRIDAY BASED ON
THERMAL PROFILES FROM BUFKIT SOUNDINGS AS WELL AS PARTIAL
THICKNESSES. FRIDAY NIGHT AND SATURDAY...THE NORTHWESTERN COUNTIES
WOULD HAVE A HIGHER CHANCE OF MIXED OR FROZEN PRECIPITATION THAN THE
SOUTHEAST AS COLDER AIR MOVES IN FROM THE NORTHWEST IN THE WAKE OF
THE SURFACE SYSTEM. BUFKIT SOUNDINGS EVEN SUGGEST FREEZING RAIN OR
SLEET COULD POSSIBLY MIX IN AT TIMES FRIDAY NIGHT.
GENERALLY ACCEPTED THE REGIONAL BLEND TEMPERATURES. DO NOT FEEL
CONFIDENT ENOUGH TO MAKE CHANGES UNTIL THE MODELS HOPEFULLY COME
CLOSER TOGETHER IN SUBSEQUENT RUNS. AFTERNOON HIGHS IN THE 20S LOOK
GOOD ON NEW YEAR`S DAY WITH HIGHS MOSTLY IN THE 30S THEREAFTER.
MEANWHILE...NEW YEARS EVE NIGHT SHOULD BE THE COLDEST WITH OVERNIGHT
LOWS IN THE TEENS FOR THE FIRST SUNRISE OF THE YEAR. OVERNIGHT LOWS
WILL MOSTLY BE IN THE 20S AND 30S BY LATE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 27/21Z TAF UPDATE/...
ISSUED AT 320 PM EST SAT DEC 27 2014
SOME ADJUSTMENT DOWNWARD TO CEILINGS AND VISIBILITIES REQUIRED TO
INITIAL PERIOD OF TAFS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1200 PM EST SAT DEC 27 2014
DECENT CONFIDENCE THAT MVFR OR WORSE FLYING CONDITIONS ARE EXPECTED
TO BE OVER THE TERMINALS THE MAJORITY OF THIS AFTERNOON AND TONIGHT
BEFORE CONDITIONS IMPROVE TO VFR TOMORROW. MEANWHILE...RAIN WILL BE
INCREASING AT OR SHORTLY AFTER ISSUANCE TIME AND SHOULD END AFTER
04Z AT LAF...06Z AT IND AND HUF AND 08Z AT BMG.
A COLD FRONT SHOULD REACH LAF AND HUF AROUND 22Z AND IND AND BMG
AROUND 00Z. WINDS WILL SWITCH FROM SOUTHWEST TO WEST AND THEN
NORTHWEST AFTER THE FRONTAL PASSAGE. WIND SPEEDS WILL BE 9 TO 12
KNOTS THIS AFTERNOON AND EVENING AND LESS THAN 10 KNOTS TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM...MK
AVIATION...MK/NIELD
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
310 AM CST SAT DEC 27 2014
...UPDATED LONG TERM SECTION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 258 PM CST FRI DEC 26 2014
THE NAM MODEL SEEMED TO OUTPERFORM THE HRRR WITH RESPECT TO
PRECIP PLACEMENT LATE THIS MORNING AND EARLY AFTERNOON. THE MODEL
WILL CONTINUE TO BE USED AS A GUIDE IN COMBINATION WITH CURRENT
TRENDS TO PLACE POPS AND QPF/SNOW AMOUNTS FOR THE REST
AFTERNOON/EVENING. A DECISION WILL NEED TO BE MADE WHETHER TO
EXTEND EITHER IN TIME AND AREAL COVERAGE OR DROP THE ADVISORY
ALTOGETHER AT 4 PM. AT THIS TIME, EXTENSION DOES NOT APPEAR TO BE
LIKELY. THE NAM INDICATED AN INTSENSIFICATION OF FRONTOGENESIS IN
THE MID TO LATE AFTERNOON, HOWEVER IT IS ASSOCIATED WITH NON
FAVORABLE AGEOSTROPHIC FLOW FOR VERTICAL MOTION. ONCE THE SNOW
BEGINS TO WIND DOWN FROM THE DISSIPATION OF VERTICAL MOTION, CLOUD
CEILING HEIGHTS WILL BEGIN TO INCREASE FROM WEST TO EAST THIS
EVENING. FOG SHOULD NOT BE A BIG CONCERN HEADING INTO THE
OVERNIGHT AS SURFACE BOUNDARY LAYER AIR SEES A BUMP IN DEW POINT
TEMPERATURES (WHICH THE NAM SEEMS TO REFLECT), AS SURFACE WINDS
WILL BE WELL ENOUGH MIXED AND SLIGHTLY DOWNSLOPED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 310 AM CST SAT DEC 27 2014
MOSTLY CLEAR SKIES ARE EXPECTED ON SUNDAY WITH WESTERLY FLOW ALOFT
AND DRY CONDITIONS IN PLACE IN THE MID LEVELS OF THE ATMOSPHERE.
SOUTHWEST WINDS WILL BE FELT AT THE SURFACE WITH A TROUGH OF LOW
PRESSURE POSITIONED ACROSS EASTERN COLORADO. AN UPPER LEVEL TROUGH
THEN DEEPENS ACROSS THE WESTERN UNITED STATES MONDAY. THIS WILL
HELP PUSH A COLD FRONT AT THE SURFACE SOUTH ACROSS NEBRASKA AND
INTO WESTERN KANSAS IN THE AFTERNOON. THE ATMOSPHERE WILL BECOME
SATURATED BEHIND THIS FRONT INCREASING CLOUDINESS. A FEW SNOW
SHOWERS MAY FORM IN THE LATE AFTERNOON INTO OVERNIGHT PERIOD WITH
DECREASING CHANCES ON TUESDAY. MOSTLY CLOUDY SKIES CONTINUE
THROUGH TUESDAY NIGHT WITH NORTHERLY WINDS AND WELL BELOW NORMAL
TEMPERATURES. PARTLY CLOUDY SKIES AND DRY CONDITIONS ARE EXPECTED
MID WEEK AS A DOME OF HIGH PRESSURE MOVES SOUTHWARD ACROSS THE
CENTRAL PLAINS. THE NEXT CHANCE OF PRECIPITATION IS EXPECTED LATE
WEEK INTO THIS WEEKEND AS THE AFOREMENTIONED UPPER LEVEL TROUGH
DEEPENS INTO A LOW AND EJECTS EASTWARD TOWARDS THE PLAINS. AS FOR
TEMPERATURES, HIGHS SUNDAY LOOK TO REACH INTO THE 30S WITH LOWS IN
THE UPPER TEENS AND LOWER 20S. HIGHS MONDAY LOOK TO RANGE FROM
AROUND 20 DEGREES ACROSS WEST CENTRAL KANSAS TO MID 30S ACROSS
SOUTH CENTRAL KANSAS. THIS IS DUE TO THE COLD FRONT MOVING THROUGH
THE AREA IN THE AFTERNOON. HIGHS IN THE TEENS ARE THEN ANTICIPATED
TUESDAY WITH LOWS DIPPING INTO THE SINGLE DIGITS AND POSSIBLY EVEN
BELOW ZERO ACROSS WEST CENTRAL KANSAS BY SUNRISE WEDNESDAY.
TEMPERATURES THEN SLOWLY REBOUND TO THE 30S BY FRIDAY WITH LOWS
INCREASING INTO THE TEENS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1128 PM CST FRI DEC 26 2014
A VERY QUIET PATTERN WILL DOMINATE WESTERN AND CENTRAL KANSAS THE
REMAINDER OF TONIGHT AND LASTING THROUGH SATURDAY. SPECIFICALLY,
THE UPPER TROUGH BRINGING SNOW AND IFR CEILINGS ON FRIDAY, WILL
SHIFT SLOWLY EAST ACROSS THE GREAT PLAINS ON SATURDAY. THIS WILL
ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE CENTRAL PLAINS WITH
ONLY SOME SCATTERED VFR CLOUD COVER EXPECTED. OTHERWISE, NORTHWEST
WINDS AROUND 10 KT WILL TURN LIGHT AND VARIABLE BY SUNSET ON
SATURDAY WHILE THE VISIBILITY IS UNLIMITED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 14 38 17 / 0 0 0 0
GCK 32 12 37 15 / 0 0 0 0
EHA 31 16 40 17 / 0 0 0 0
LBL 33 14 39 18 / 0 0 0 0
HYS 30 14 37 17 / 0 0 0 0
P28 36 17 41 21 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...HOVORKA_42
AVIATION...AJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1128 PM CST FRI DEC 26 2014
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 258 PM CST FRI DEC 26 2014
THE NAM MODEL SEEMED TO OUTPERFORM THE HRRR WITH RESPECT TO
PRECIP PLACEMENT LATE THIS MORNING AND EARLY AFTERNOON. THE MODEL
WILL CONTINUE TO BE USED AS A GUIDE IN COMBINATION WITH CURRENT
TRENDS TO PLACE POPS AND QPF/SNOW AMOUNTS FOR THE REST
AFTERNOON/EVENING. A DECISION WILL NEED TO BE MADE WHETHER TO
EXTEND EITHER IN TIME AND AREAL COVERAGE OR DROP THE ADVISORY
ALTOGETHER AT 4 PM. AT THIS TIME, EXTENSION DOES NOT APPEAR TO BE
LIKELY. THE NAM INDICATED AN INTSENSIFICATION OF FRONTOGENESIS IN
THE MID TO LATE AFTERNOON, HOWEVER IT IS ASSOCIATED WITH NON
FAVORABLE AGEOSTROPHIC FLOW FOR VERTICAL MOTION. ONCE THE SNOW
BEGINS TO WIND DOWN FROM THE DISSIPATION OF VERTICAL MOTION, CLOUD
CEILING HEIGHTS WILL BEGIN TO INCREASE FROM WEST TO EAST THIS
EVENING. FOG SHOULD NOT BE A BIG CONCERN HEADING INTO THE
OVERNIGHT AS SURFACE BOUNDARY LAYER AIR SEES A BUMP IN DEW POINT
TEMPERATURES (WHICH THE NAM SEEMS TO REFLECT), AS SURFACE WINDS
WILL BE WELL ENOUGH MIXED AND SLIGHTLY DOWNSLOPED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 327 PM CST FRI DEC 26 2014
MEDIUM RANGE MODELS INDICATE A POSITIVELY TILTED UPPER LEVEL TROUGH
OF LOW PRESSURE SHIFTING EASTWARD OUT OF THE DESERT SOUTHWEST INTO
THE SOUTH PLAINS SUNDAY BRINGING ABOUT A WESTERLY FLOW ALOFT TO THE
WESTERN HIGH PLAINS. A WEAKENING FLOW ALOFT COMBINED WITH A LACK OF
LOW/MID LEVEL MOISTURE WILL RESULT IN DRY CONDITIONS PREVAILING
ACROSS WESTERN KANSAS THROUGH LATE MONDAY MORNING. PRECIP CHANCES
WILL INCREASE A LITTLE MONDAY AFTERNOON AS DEEPENING UPPER LEVEL
TROUGH DROPS SOUTHWARD ACROSS THE PACIFIC NORTHWEST SETTING UP A
DIFLUENT FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS. THIS WILL
COINCIDE WITH ANOTHER STRONG COLD FRONT PUSHING SOUTHWARD ACROSS
WESTERN KANSAS AS THE FLOW ALOFT STRENGTHENS AFTER EXITING THE
TROUGH AXIS OUT WEST. AS A RESULT, SNOW IS LIKELY TO DEVELOP
ACROSS THE HIGH PLAINS OF COLORADO MONDAY WITH THE POTENTIAL FOR
SNOW SPREADING EASTWARD INTO PORTIONS OF WESTERN KANSAS FROM
MONDAY AFTERNOON THROUGH EARLY TUESDAY MORNING. ALTHOUGH IT IS TOO
EARLY TO DETERMINE SNOW AMOUNT POTENTIAL, WEAK QPF SIGNALS SUGGEST
LIGHTER AMOUNTS, IF ANY.
ALTHOUGH REBOUNDING SOMEWHAT, TEMPERATURES WILL REMAIN BELOW NORMAL
SUNDAY WITH COLDER AIR SLOW TO ERODE AS A LEE SIDE TROUGH OF LOW
PRESSURE DEVELOPS ACROSS EASTERN COLORADO. THE GFS/ECMWF SHOW THE
H85 0C ISOTHERM BEGINNING TO EDGE BACK TO THE NORTH BUT REMAINING
WELL SOUTH OF CENTRAL AND MUCH OF SOUTHWEST KANSAS. EVEN WITH
DECREASED CLOUD COVER EXPECTED, LOOK FOR HIGHS ONLY UP INTO THE
30S(F) SUNDAY AFTERNOON WITH NEAR 40F STILL A POSSIBILITY CLOSER TO
THE OKLAHOMA BORDER. THE GFS AND ECMWF CONTINUE TO PROJECT A
STRONG ARCTIC COLD FRONT PUSHING THROUGH WESTERN KANSAS MONDAY
BRINGING ANOTHER ROUND OF COLD AIR SURGING SOUTHWARD INTO THE
REGION EARLY NEXT WEEK. HIGHS COULD BE AS LOW AS THE TEENS(F)
TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1128 PM CST FRI DEC 26 2014
A VERY QUIET PATTERN WILL DOMINATE WESTERN AND CENTRAL KANSAS THE
REMAINDER OF TONIGHT AND LASTING THROUGH SATURDAY. SPECIFICALLY,
THE UPPER TROUGH BRINGING SNOW AND IFR CEILINGS ON FRIDAY, WILL
SHIFT SLOWLY EAST ACROSS THE GREAT PLAINS ON SATURDAY. THIS WILL
ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE CENTRAL PLAINS WITH
ONLY SOME SCATTERED VFR CLOUD COVER EXPECTED. OTHERWISE, NORTHWEST
WINDS AROUND 10 KT WILL TURN LIGHT AND VARIABLE BY SUNSET ON
SATURDAY WHILE THE VISIBILITY IS UNLIMITED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 32 16 38 / 20 0 0 0
GCK 12 31 15 36 / 10 0 0 0
EHA 13 32 16 39 / 10 0 0 0
LBL 16 34 15 39 / 10 0 0 0
HYS 16 29 15 36 / 20 0 0 0
P28 21 38 18 41 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...JJOHNSON
AVIATION...AJOHNSON
AREA FORECAST DISCUSSION
NWS JACKSON KY
1101 PM EST SUN DEC 28 2014
.UPDATE...
ISSUED AT 1100 PM EST SUN DEC 28 2014
RAIN IS TAPERING OFF SLIGHTLY FASTER THAN WAS NOTED IN THE PREVIOUS
UPDATE. TRIMMED BACK POPS AND HAVE THEM MOVING SE AT A FASTER RATE
NOW TO BETTER COORDINATE WITH THE CURRENT RADAR TRENDS. EVEN
STILL...WON/T BE SURPRISED IF THE POPS END UP MOVING OUT EVEN FASTER
THAN THE CURRENT FORECAST. THE CURRENT HRRR MODEL WOULD SUGGEST
CONTINUED SE MOVEMENT OF THE RAIN MOVING OUT OF MUCH OF THE CWA
BY 7Z...BUT BECOMING STALLED OUT ACROSS THE HIGHER TERRAIN FROM 7Z
THROUGH TOMORROW MORNING. THE MODEL HAS INITIALIZED WELL...BUT THIS
WILL BE SOMETHING TO WATCH.
UPDATE ISSUED AT 647 PM EST SUN DEC 28 2014
TWO MAIN CHANGES TO THE FORECAST. FIRST WAS TO CHANGE THE POPS OVER
THE NEXT FEW HOURS TO CENTER THE HIGHEST AMOUNTS OVER THE MORE
CENTRAL PORTION OF THE CWA...SLOWLY SHIFTING MORE EASTWARD INTO THE
HIGHEST TERRAIN OVER THE NEXT SEVERAL HOURS...THEN LINGERING SLIGHTLY
LONGER ACROSS THE SW CWA THAN WAS PREVIOUSLY FORECAST. THIS BETTER
ACCOUNTED FOR ONGOING CONDITIONS...AS WELL AS WHAT BOTH THE HI RES
AND SHORT TERM MODELS WERE FORECASTING. THE SECOND CHANGE WAS TO ADD
FOG WORDING TO THE CWA THROUGH THE OVERNIGHT HOURS. MUCH OF KY IS
REPORTING FOG...IN AREAS WITH AND WITHOUT RAIN. EXPECT THIS FOG TO
CONTINUE AS WE HEAD INTO THE OVERNIGHT HOURS WITH LOW LEVEL MOISTURE
FROM RAIN EXPECTED TO CONTINUE. THIS FOG SHOULD THEN BURN OFF DURING
THE MORNING HOURS AS DRIER AIR MOVES IN AND RAIN MOVES OUT. VALLEYS
WILL BE THE LAST TO CLEAR OUT. UPDATED THE NEAR TERM GRIDS WITH THE
LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS TO MAKE
SURE THE CURRENT CONDITIONS WERE REFLECTED IN THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 359 PM EST SUN DEC 28 2014
CURRENT CONDITIONS ACROSS THE AREA FEATURES RAIN CONTINUING TO MOVE
INTO THE AREA FROM THE SOUTHWEST. THE COLD FRONT HAS NOW PUSHED EAST
OF EASTERN KENTUCKY WITH NORTHWESTERLY FLOW NOW INTO THE AREA.
FREEZING TEMPERATURES LOOK TO BE NORTH AND WEST OF THE FORECAST AREA
AND SNOW IS NOT EXPECTED AT THIS TIME AS THE COLDER AIR IS A BIT TO
SLOW TO ADVECT INTO THE AREA BEFORE THE BULK OF THE MOISTURE EXITS TO THE
EAST TONIGHT. MEANWHILE...SURFACE LOW PRESSURE HAS DEVELOPED AND WILL
MOVE NORTHEAST THROUGH EASTERN TN TONIGHT. THIS WILL KEEP PRECIP
THROUGH FAR EASTERN KENTUCKY THROUGH THE NIGHT AS ANOTHER SURGE OF
MOISTURE WILL MOVE NORTHEAST. WITH THE MOIST LOW LEVELS...THOUGH
THERE WILL BE SOME CLOUD COVER...DO EXPECT SOME PATCHY FOG DEVELOPING
TONIGHT AND HAS ALREADY BEEN THE CASE IN SOME OF THE BLUEGRASS AREAS.
ESPECIALLY PLACES THAT REMAIN SATURATED THROUGH THE NIGHT.
CLOUD COVER AND PRECIP WILL SLOWLY MOVE OFF TO THE EAST FOR MONDAY
WITH SOME RAIN FALL SKIRTING ALONG THE FAR EASTERN COUNTIES AS THE
LOW EXITS OF TO THE EAST. HEADING INTO MONDAY NIGHT...THE COLDER AIR
WILL FILTER INTO THE AREA AND SOME LINGERING RAIN IN THE EAST MAY
CHANGE OR MIX TO SNOW IN THE HIGHER ELEVATIONS TOWARDS TUESDAY
MORNING. PARTIAL CLEARING IN THE NORTHWESTERN COUNTIES WILL RESULT IN
TEMPERATURES DROPPING INTO THE MID 20S FOR LOWS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 PM EST SUN DEC 28 2014
THE EXTENDED PORTION OF THE FORECAST WILL BE BROKEN UP INTO THREE
SEGMENTS. PART ONE...ISOLATED RAIN AND SNOW SHOWERS ARE FORECAST TO
LINGER IN THE NORTHERLY MEAGERLY MOIST FLOW BEHIND A DEPARTING COLD
FRONT AND UPPER LEVEL LOW PRESSURE SYSTEM. THE SECOND PERIOD WILL
FEATURE AN EAST TO WEST ELONGATED RIDGE OF HIGH PRESSURE THAT IS
EXPECTED TO DROP SOUTHWARD OUT OF THE GREAT LAKES REGION TUESDAY
THROUGH THURSDAY. PART THREE WILL FEATURE A WELL DEVELOPED AND VERY
MOISTURE LADEN WEATHER SYSTEM THAT WILL AFFECT THE REGION FROM
THURSDAY NIGHT THROUGH SUNDAY. THE WEATHER SYSTEM THAT WILL BE
LEAVING THE AREA ON TUESDAY SHOULD BRING NOTHING MORE THAN LIGHT
RAIN AND SNOW WITH LITTLE OR NO SNOW ACCUMULATION. TEMPERATURES TO
BEGIN THE PERIOD LOOK TO BE BELOW NORMAL...WITH HIGHS IN THE 40S
DURING THE DAY...AND LOWS TUESDAY NIGHT IN THE LOW TO MID 20S. AN
ARCTIC AIR MASS IS THEN PROGGED TO SETTLE OVER THE REGION MID WEEK.
HIGHS ON WEDNESDAY AND THURSDAY WILL LIKELY NOT MAKE IT OUT OF THE
30S. OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT WILL BE EVEN
CHILLIER...WITH THE MERCURY BOTTOMING OUT AROUND 20 WEDNESDAY
NIGHT...AND THE MID TO UPPER 20S THURSDAY NIGHT.
THE BIG STORY IN THE EXTENDED WILL BE THE WEATHER SYSTEM THAT IS
FORECAST TO SOAK THE AREA TOWARD THE END OF THE WEEK. THERE IS NO
QUESTION THAT A POTENT WEATHER SYSTEM WITH EXTENSIVE PRECIPITATION
WILL AFFECT THE STATE OF KENTUCKY FRIDAY AND SATURDAY. THE QUESTIONS
WITH THIS SYSTEM WILL BE HOW QUICKLY WILL PRECIPITATION MOVE INTO
THE AREA AND HOW MUCH OF THE PRECIP WILL BE IN THE FORM OF SNOW?
RIGHT NOW THE GFS IS MUCH SLOWER AND WARMER THAN THE ECMWF WITH THE
END OF WEEK WEATHER PATTERN. THE GFS HAS ITS LOW MOVING FURTHER
NORTH THAN THE ECMWF. THAT BEING SAID...WITH SO MUCH UNCERTAINTY
INVOLVED...DECIDED TO GO WITH A COMPROMISE BETWEEN THE TWO
MODELS...SLIGHTLY FAVORING THE COLDER ECMWF MODEL. THIS IS BASED ON
THE FACT THAT THE MODELS HAVE BEEN RUNNING A BIT TOO WARM LATELY
WITH REGARDS TO LOW AND MIDDLE LEVEL TEMPERATURES. AFTER A PERIOD OF
MIXED PRECIP THURSDAY EVENING...AN AREA OF LIGHT SNOW IS BEING
FORECAST TO DEVELOP LATE THURSDAY NIGHT THROUGH EARLY FRIDAY
MORNING. THERE COULD BE SOME LIGHT ACCUMULATIONS WITH THIS BAND OF
SNOW AS IT MOVES NORTH...BUT IT WILL LIKELY NOT STAY ON THE GROUND
LONG AS TEMPERATURES RISE INTO THE 40S ON FRIDAY. AN EXTENDED PERIOD
OF GOOD SOAKING RAIN IS EXPECTED FRIDAY THROUGH SATURDAY...WITH THE
POTENTIAL FOR SOME SNOW ALONG AND NORTH OF I-64 FRIDAY NIGHT AND
SATURDAY NIGHT...AS SOME NEAR FREEZING AIR COULD SPILL INTO THAT
AREA EACH NIGHT. AS IS COMMON IN WINTER...THE MODELS WILL NEED TO BE
WATCHED VERY CLOSELY TO SEE WHICH DIRECTION THINGS TREND...MORE RAIN
OR MORE SNOW WILL BE THE QUESTION AS WE MOVE FORWARD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 701 PM EST SUN DEC 28 2014
A COLD FRONT HAS MOVED SE OF KY...THOUGH RAIN WILL LIKELY LINGER
THROUGHOUT MUCH OF THE NIGHT AT THE TAF SITES. DESPITE SURFACE WINDS
SWITCHING TO A MORE NRLY DIRECTION BEHIND THIS FRONT...THE MID AND
UPPER LEVELS STILL POSSESS A STRONG SWRLY COMPONENT...ALLOWING THIS
MOISTURE TO CONTINUE TO FILTER INTO THE REGION. FOG IS BEING OBSERVED
NOW ACROSS MUCH OF KENTUCKY...AND WITH MOISTURE EXPECTED TO CONTINUE
OVERNIGHT...THE FOG WILL LIKELY LINGER INTO THE MORNING HOURS. WHILE
CIGS WILL REMAIN NEAR OR AT AIRPORT MINIMUMS...THE FOG AND RAIN WILL
LIKELY KEEP VIS FLUCTUATING BETWEEN LIFR AND BELOW AIRPORT MINS.
GIVEN THE UNCERTAINTY AND LIKELY VARIABILITY IN THIS WEATHER
PATTERN...WENT WITH A GENERAL AND OPTIMISTIC 1SM AT THE TAF SITES
DURING THE OVERNIGHT HOURS. FOG WILL BURN OFF AND VIS WILL SLOWLY
IMPROVE TOMORROW MORNING. ANOTHER WEAKER BOUNDARY IS EXPECTED TO MOVE
THROUGH THE REGION DURING THE AFTERNOON FROM THE NW...SO CIGS WILL
LIKELY REMAIN MVFR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
1257 PM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 1256 PM EST SAT DEC 27 2014
ALL OF THE SPRINKLES AND WEAK SHOWER ACTIVITY HAS DISSIPATED AND
UPSTREAM...WHICH IS DOWN TO THE WEST AND SOUTHWEST...MORE SHOWERS ARE
MOVING NORTHEAST INTO THE FORECAST AREA. HAVE UPDATED THE FORECAST TO
TAKE OUT MORNING MENTION OF SPRINKLES AND SHOWERS. THE BULK OF THE
ACTIVITY WILL MAKE IT INTO THE FAR WESTERN PORTIONS OF THE CWA
TOWARDS THE EVENING TIME FRAME. TEMPERATURES ARE ALSO A BIT WARMER
INTO THIS AFTERNOON THAN ANTICIPATED SO BUMPED UP THE TEMPS A DEGREE
OR TWO...ESPECIALLY IN THE SOUTHERN LOCATIONS. HAVE ISSUED A NEW ZFP
TO ADDRESS THIS UPDATE.
UPDATE ISSUED AT 1040 AM EST SAT DEC 27 2014
THE SPRINKLE AND SHOWER ACTIVITY IS BEGINNING TO WIND DOWN AS IT
SHIFTS TO THE NORTHEAST THROUGH THE AREA. IT SEEMS THAT THE CURRENT
FORECAST HAS THE PRECIP HANDLED FOR NOW. WILL HAVE TO ISSUE A NEW ZFP
WHEN THE PRECIP EXITS THE AREA AS THERE WILL BE MORNING WORDING THAT
NEEDS ADDRESSED ANYWAY. DESPITE THIS LIGHT ACTIVITY...THE MORNING
INTO THE NOON PERIOD LOOKS TO BE QUIET. TRENDS ARE STILL ON TRACK FOR
THE LARGE SWATH OF PRECIP TO ARRIVE THIS EVENING. FOR NOW...JUST SENT
OUT A NEW SET OF GRIDS WITH THE LATEST OBS AND WILL CONTINUE TO
ADDRESS THE LIGHT SPRINKLES WITH A GRAPHICAL NOW CAST.
UPDATE ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...THE HRRR
HAS TRENDED SLOWER WITH THE OVERALL DISSIPATION WITH EACH NEW RUN.
MOST RECENT RUN INDICATES THAT SOME OF THE SHOWER ACTIVITY COULD
HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH SOME RAIN...MAINLY
ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS TO BE SUPPORTED BY
THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT THUS FAR. THEREFORE
INTRODUCED POPS ACROSS OUR NORTH FOR THE EARLY AND MID MORNING TIME
FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO INCLUDED A
SWATH OF SPRINKLES AHEAD OF THIS INITIAL BAND FOR SOME AREAS THAT
ARE NOT EXPECTED TO SEE ACTUAL SHOWERS. OTHERWISE FORECAST APPEARS ON
TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1256 PM EST SAT DEC 27 2014
VFR CONDITIONS OVER THE AREA WILL BEGIN TO DEGRADE THROUGH THE
EVENING TO MVFR AND IFR CONDITIONS OVER NIGHT AS A MOISTURE LADEN
SYSTEM DEVELOPS AND MOVES NORTHEAST OUT OF THE LOWER MS RIVER VALLEY.
EXPECT RAIN TO DEVELOP INTO THE AREA AFTER 00Z WITH CEILINGS DROPPING
TO AIRFIELD MINIMUMS BY 12Z OVER MUCH OF THE AREA AND CONTINUING
THROUGH THE END OF THE TAF PERIOD. RAIN IS EXPECTED TO BE WIDESPREAD
THROUGH THE REST OF THE TAF PERIOD WITH LIGHT WINDS EXPECTED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
1040 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 1040 AM EST SAT DEC 27 2014
THE SPRINKLE AND SHOWER ACTIVITY IS BEGINNING TO WIND DOWN AS IT
SHIFTS TO THE NORTHEAST THROUGH THE AREA. IT SEEMS THAT THE CURRENT
FORECAST HAS THE PRECIP HANDLED FOR NOW. WILL HAVE TO ISSUE A NEW ZFP
WHEN THE PRECIP EXITS THE AREA AS THERE WILL BE MORNING WORDING THAT
NEEDS ADDRESSED ANYWAY. DESPITE THIS LIGHT ACTIVITY...THE MORNING
INTO THE NOON PERIOD LOOKS TO BE QUIET. TRENDS ARE STILL ON TRACK FOR
THE LARGE SWATH OF PRECIP TO ARRIVE THIS EVENING. FOR NOW...JUST SENT
OUT A NEW SET OF GRIDS WITH THE LATEST OBS AND WILL CONTINUE TO
ADDRESS THE LIGHT SPRINKLES WITH A GRAPHICAL NOW CAST.
UPDATE ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...THE HRRR
HAS TRENDED SLOWER WITH THE OVERALL DISSIPATION WITH EACH NEW RUN.
MOST RECENT RUN INDICATES THAT SOME OF THE SHOWER ACTIVITY COULD
HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH SOME RAIN...MAINLY
ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS TO BE SUPPORTED BY
THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT THUS FAR. THEREFORE
INTRODUCED POPS ACROSS OUR NORTH FOR THE EARLY AND MID MORNING TIME
FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO INCLUDED A
SWATH OF SPRINKLES AHEAD OF THIS INITIAL BAND FOR SOME AREAS THAT
ARE NOT EXPECTED TO SEE ACTUAL SHOWERS. OTHERWISE FORECAST APPEARS ON
TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EST SAT DEC 27 2014
SHOWERS ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL
DEVELOP ACROSS THE REGION TODAY...DROPPING FLIGHT CONDITIONS INTO
MVFR TERRITORY FROM WEST TO EAST LATE THIS AFTERNOON AND THIS
EVENING. CONDITIONS WORSEN OVERNIGHT AS RAIN PICKS UP AND LINGERS
THROUGH THE REMAINDER OF THE FORECAST. WINDS WILL RUN LESS THAN 10
KTS THROUGH THE PERIOD...GENERALLY FROM THE SOUTH/SOUTHWEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION...CORRECTED
NWS JACKSON KY
744 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...THE HRRR
HAS TRENDED SLOWER WITH THE OVERALL DISSIPATION WITH EACH NEW RUN.
MOST RECENT RUN INDICATES THAT SOME OF THE SHOWER ACTIVITY COULD
HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH SOME RAIN...MAINLY
ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS TO BE SUPPORTED BY
THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT THUS FAR. THEREFORE
INTRODUCED POPS ACROSS OUR NORTH FOR THE EARLY AND MID MORNING TIME
FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO INCLUDED A
SWATH OF SPRINKLES AHEAD OF THIS INITIAL BAND FOR SOME AREAS THAT
ARE NOT EXPECTED TO SEE ACTUAL SHOWERS. OTHERWISE FORECAST APPEARS ON
TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EST SAT DEC 27 2014
SHOWERS ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL
DEVELOP ACROSS THE REGION TODAY...DROPPING FLIGHT CONDITIONS INTO
MVFR TERRITORY FROM WEST TO EAST LATE THIS AFTERNOON AND THIS
EVENING. CONDITIONS WORSEN OVERNIGHT AS RAIN PICKS UP AND LINGERS
THROUGH THE REMAINDER OF THE FORECAST. WINDS WILL RUN LESS THAN 10
KTS THROUGH THE PERIOD...GENERALLY FROM THE SOUTH/SOUTHWEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
730 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...RECENT RUNS
HAS SHOWN A SLOWER TREND OVERALL WITH INDICATIONS THAT SOME OF THE
SHOWER ACTIVITY COULD HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH
SOME RAIN...MAINLY ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS
TO BE SUPPORTED BY THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT
THUS FAR. THEREFORE INTRODUCED POPS ACROSS OUR NORTH FOR THE MID
MORNING TIME FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO
INCLUDED A WIDER SWATH OF SPRINKLES FOR SOME AREAS THAT MAY NOT SEE
ANY RAIN THIS MORNING. OTHERWISE FORECAST APPEARS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EST SAT DEC 27 2014
SHOWERS ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL
DEVELOP ACROSS THE REGION TODAY...DROPPING FLIGHT CONDITIONS INTO
MVFR TERRITORY FROM WEST TO EAST LATE THIS AFTERNOON AND THIS
EVENING. CONDITIONS WORSEN OVERNIGHT AS RAIN PICKS UP AND LINGERS
THROUGH THE REMAINDER OF THE FORECAST. WINDS WILL RUN LESS THAN 10
KTS THROUGH THE PERIOD...GENERALLY FROM THE SOUTH/SOUTHWEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
339 AM EST SAT DEC 27 2014
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 108 AM EST SAT DEC 27 2014
LOOK FOR VFR CONDITIONS THROUGH THE ENTIRE FORECAST PERIOD. RADAR IS
PICKING UP ON A RATHER LARGE AREA OF LIGHT ECHOS TONIGHT. HAVE EVEN
SEEN SOME -IP/-RA HERE AT JKL AS ONE CELL INTENSIFIED SUDDENLY. BUT
THE BULK OF THIS ACTIVITY IS VIRGA AND AS SUCH DID NOT MENTION ANY
WEATHER AT ANY OF OUR TERMINALS. ALSO EXPECT THIS ACTIVITY TO WANE
AS WE PROGRESS THROUGH THE EARLY MORNING HOURS. ADDITIONAL SHOWERS
ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL DEVELOP
DURING THE LAST FEW HOURS OF THE FORECAST. CIGS AND VSBYS WILL DROP
THEREAFTER...JUST BEYOND THE FORECAST WINDOW. WINDS WILL RUN LESS
THAN 10 KTS THROUGH THE PERIOD...AND GENERALLY FROM THE S/SW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
615 PM EST SUN DEC 28 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 216 PM EST SUN DEC 28 2014
PERSISTENT LIGHT AND FLUFFY LAKE EFFECT IN THE NORTHWEST WIND SNOW
BELTS WILL BE THE NORM FOR THE SHORT TERM FORECAST.
A SURFACE TROUGH SWEPT SOUTHEAST ACROSS UPPER MICHIGAN THIS
MORNING AND EARLY AFTERNOON AND HAS SWITCHED WINDS TO THE NORTHWEST
AND BROUGHT MUCH COLDER AIR INTO THE AREA. 850MB TEMPS AT THIS TIME
ON THE RAP ANALYSIS ARE -18C OVER WESTERN LAKE SUPERIOR AND WESTERN
UPPER MICHIGAN. THIS COLD AIR...AIDED BY MOISTURE FROM THE SURFACE
TROUGH THAT SWEPT THROUGH THE AREA...LED TO SOME LAKE EFFECT SNOW IN
THE WEST AND NOW NORTHWEST WIND SNOWBELTS THROUGH THE DAY. WHILE
THERE WERE SOME STRONGER SHOWERS THIS MORNING...ASSISTED BY
CONVERGENCE ALONG THE FRONT AND FROM THE SOUTHERN EDGE OF THE
SHORTWAVE MOVING EAST JUST TO THE NORTH OF LAKE SUPERIOR...THEY HAVE
NOW TRANSITIONED TO MORE OF A MULTIBAND LES LOOK ON SATELLITE OVER
WESTERN UPPER MICHIGAN. USING THE EXPERIMENTAL SSEC SATELLITE
DERIVED SNOWFALL RATES...IT APPEARS THAT SOME AREAS ARE SEEING
TRANSIENT BANDS OF 0.5 IN/HR RATES AND THAT SEEMS TO MATCH UP WITH
VISIBILITY REPORTS AT KCMX. WITH THE DEEPER MOISTURE STARTING TO
PULL OUT OF THAT AREA...HAVE ALREADY SEEN SOME WEAKENING OVER
WESTERN LAKE SUPERIOR...HELPED BY INVERSION HEIGHTS FALLING
BEHIND THE TROUGH. THE 12Z KINL SOUNDING HAD INVERSION HEIGHTS
AROUND 900MB OR 3KFT...BUT WITH SOME LAKE MODIFICATION THEY SHOULD
BE IN THE 4-5KFT RANGE. OVER THE EAST...THERE WAS A STRONGER BAND
BETWEEN MUNISING AND MINER/S CASTLE THIS MORNING THAT LIKELY
PRODUCED A COUPLE-FEW INCHES OF SNOW. THIS BAND WAS AIDED BY THE
CONVERGENT FLOW OFF MARQUETTE COUNTY AHEAD OF THE SURFACE TROUGH.
BUT NOW THAT THE TROUGH IS MOVING THROUGH NORTH CENTRAL UPPER
MICHIGAN...THE BAND HAS BECOME MUDDLED. WITH THE LAKE EFFECT
TRANSITIONING TO MULTIBAND OVER THE EASTERN LAKE...ACCUMULATIONS
SHOULD BE LIMITED THE REST OF THE AFTERNOON.
OVERALL...LITTLE CHANGE IN THE OVERALL CONDITIONS OVER THE CWA
DURING THE SHORT TERM PERIOD...AS HIGH PRESSURE RIDGE BUILDS OVER
THE AREA FROM A STRONG HIGH IN NORTHWEST CANADA. WITH 875MB TEMPS
FALLING TO -21C...EXPECT HIGH POP LOW QPF LAKE EFFECT TO CONTINUE
THROUGH THE PERIOD IN THE NORTHWEST WIND SNOWBELTS. THERE DOES
APPEAR TO BE A BRIEF PERIOD OF BACKING WINDS OVERNIGHT AS A WEAK
TROUGH MOVES THROUGH TONIGHT BEFORE SETTLING BACK TO NORTHWEST WINDS
FOR MONDAY. THIS WEAK TROUGH WILL BRING A LITTLE MORE LOW LEVEL
MOISTURE TO THE AREA FOR THE LAKE EFFECT TO WORK WITH LATE TONIGHT
INTO MONDAY MORNING (SEEN ON THE 12Z CWPL SOUNDING). BUT THE RIDGE
MOVING OVER THE AREA WILL KEEP THE LOWER INVERSION HEIGHTS IN PLACE
THROUGH THE PERIOD AND KEEP SNOWFALL AMOUNTS IN CHECK. FOR TONIGHT
AND AGAIN ON MONDAY...HAVE THE NORTHWEST WIND SNOW BELTS RECEIVING
1-3 INCHES OF FLUFFY SNOW EVERY 12 HOURS...LARGELY HELPED BY THE
ENTIRE CLOUD BEING WITHIN THE DGZ. WITH THE LONGER FETCH AND IN TURN
LAKE MODIFICATION...HAVE A LITTLE HIGHER AMOUNTS OVER THE EAST BUT
STILL ONLY LOCALIZED 4 INCH AMOUNTS. THERE ARE SOME INDICATIONS OF
LOW LEVEL DRYING LATE TOMORROW AFTERNOON WHICH COULD WEAKEN THE LAKE
EFFECT SOME AND HAVE LOWERED THE POPS A LITTLE TO ACCOUNT FOR THAT.
AS IS NORMALLY THE CASE IN THE LAKE EFFECT REGIMES...LOWS TONIGHT
WILL DEPEND ON CLOUD COVER. WHERE CLEARING IS EXPECTED TO
OCCUR...HAVE LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO.
OTHERWISE...UNDER THE CLOUDS WOULD EXPECT TEMPS IN THE UPPER SINGLE
DIGITS OR LOWER TEENS. HIGHS TOMORROW WILL BE CLOSE TO 10 DEGREES
BELOW NORMAL AND IN THE TEENS ABOVE ZERO.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 PM EST SUN DEC 28 2014
TODAYS MEDIUM RANGE MODELS STRONGLY SUPPORT LONG TERM FCST PRODUCED
OVER THE LAST 3 DAYS. SO...FCST CHANGES IN THE LONG TERM TODAY WILL
BE MINOR. BIGGEST FCST CHALLENGE WILL OCCUR AT THE END OF THE
WEEK/WEEKEND. MORE ON THAT LATER. THE LONG ADVERTISED SIGNIFICANT
PATTERN CHANGE ACROSS NAMERICA IS NOW WELL UNDERWAY AS A STRONG
RIDGE IS BUILDING N THRU ALASKA. 12Z RAOBS SHOW 12HR 500MB HEIGHT
RISES OF 130-150M IN NRN ALASKA/ADJACENT FAR NW CANADA...AND HEIGHT
ANOMALIES ARE NOW 2 STANDARD DEVIATIONS ABOVE THE LONG TERM LATE DEC
AVG. 500MB HEIGHT ANOMALIES ARE STILL FCST TO PEAK AT 2.5 STANDARD
DEVIATIONS LATER TODAY THRU EARLY WED. OF COURSE...THE DOWNSTREAM
RESPONSE WILL BE A DEVELOPING CNTRL/ERN NAMERICA TROF. THIS
AMPLIFIED PATTERN WILL ALLOW THE BUILDUP AND EXPANSION OF ARCTIC AIR
ACROSS CANADA THAT WILL SPILL S INTO THE CONUS...SIMILAR TO THE
PATTERN OBSERVED MOST OF LAST WINTER AND LAST MONTH. SO...AFTER AN
EXTENDED PERIOD OF MOSTLY ABOVE NORMAL TEMPS OVER THE LAST 3
WEEKS...A BLO NORMAL TEMP REGIME WILL TAKE HOLD ON MON AND CONTINUE
THRU AT LEAST THE NEXT 10 DAYS...THOUGH A DAY OR TWO MAY SEE TEMPS
CLOSE TO NORMAL DURING THAT TIME. THERE ARE INDICATIONS THAT THE
MOST SIGNIFICANT CHILL COULD OCCUR IN THE 7-10 DAY TIME FRAME.
FARTHER OUT TO DAY 16...MAJORITY OF GEM ENSEMBLES STILL INDICATE
DEAMPLIFICATION AND A TREND BACK TOWARD NORMAL TEMPS BY MID JAN.
CFSV2 GOES FURTHER TO BRING A RETURN OF A WARM PATTERN/ABOVE NORMAL
TEMPS FOR MID/LATE JAN. WE`LL SEE. AS FOR PCPN...PCPN THIS WEEK WILL
BE CONFINED ALMOST EXCLUSIVELY TO THE LAKE EFFECT SNOW BELTS NEAR
LAKE SUPERIOR AS COLD NW FLOW PREVAILS. AS HAS BEEN THE CASE THE
LAST FEW DAYS...THERE CONTINUE TO BE INDICATIONS THAT A LOW PRES
SYSTEM COULD TRACK FROM THE SRN PLAINS TO THE GREAT LAKES LATE
WEEK/WEEKEND. WHILE THIS STILL SEEMS LIKE A LOW PROBABILITY BASED ON
ALL AVBL MEDIUM RANGE GUIDANCE (AT LEAST AS FAR AS BRINGING
SIGNIFICANT PCPN INTO UPPER MI)...THERE ARE SUBTLE MULTI-MODEL
TRENDS SUPPORTING AN INCREASED LIKELIHOOD OF AT LEAST WIDESPREAD
-SN...INCLUDING LAKE ENHANCEMENT NEAR LAKE SUPERIOR. LATE
WEEK/WEEKEND WILL CONTINUE TO BE A TIME FRAME TO MONITOR IN THE
COMING DAYS.
BEGINNING MON NIGHT THRU TUE NIGHT...THE COLDEST AIR OF THIS INITIAL
SURGE OF ARCTIC AIR WILL SETTLE OVER THE AREA ON TUE WHEN 850MB
TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY BEING
THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL WILL
BE IN THE 5 TO 15F RANGE...THOUGH OVER THE FAR W AROUND KIWD...TEMPS
MAY ONLY RISE TO JUST ABOVE 0F. MON NIGHT AND TUE NIGHT...SUBZERO
MIN TEMPS WILL BE THE RULE IN THE INTERIOR AWAY FROM LAKE EFFECT
CLOUDS/SNOW. TUE NIGHT WILL LIKELY BE COLDEST WITH TEMPS IN THE
INTERIOR W HALF SLIPPING TO -10F OR LWR. SUBZERO TEMPS SHOULD COVER
A WIDER AREA ON TUE NIGHT AS WELL SINCE WINDS BACKING MORE WESTERLY
WILL RESULT IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI.
COMBINED WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO
THE -15 TO -25F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD
AIR...NMRS SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY
NW TO W WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO
LES WILL OVERALL BE ON THE LIGHT SIDE (1-4IN/12HRS). HOWEVER...WHERE
FETCH ACROSS THE LAKE IS LONGEST...ALLOWING MOST LAKE MODERATION...
DGZ WILL DOMINATE THE CONVECTIVE LAYER...AND THIS MAY ALLOW FOR SOME
ADVY LEVEL SNOW ACCUMULATIONS...IN PARTICULAR WHERE LONGER FETCH AND
LOCALIZED ENHANCED CONVERGENCE WORK TOGETHER. SIMILAR TO THE LAST
FEW DAYS OF MODEL RUNS...SHORTWAVE TROF SWINGING ACROSS THE AREA ON
TUE WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING
INVERSION HEIGHTS (FOR ROUGHLY 6HRS)...RESULTING IN AN INCREASE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. BLSN MAY
BECOME AN ISSUE THERE ON NEW YEARS EVE...ESPECIALLY IF SHSN COVERAGE
REMAINS NMRS OR GREATER.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH AFORMENTIONED SHORTWAVE TROF
SWINGING ACROSS NRN ONTARIO WILL THEN SWEEP ACROSS THE AREA EARLY ON
NEW YEARS DAY...ENHANCING LES FOR A TIME AND PROBABLY BRINGING AT
ISOLD/SCT -SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
INCREASING MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR A BAND OF -SN TO DEVELOP OVER THE NRN PLAINS
AND THEN STREAK E INTO THE UPPER LAKES...BUT PROBABLY NOT UNTIL FRI
NIGHT.
ON INTO SAT...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW THAT
WILL BE OVER THE SW STATES MIDWEEK. THE GFS HAS BEEN VERY CONSISTENT
ON THE NW SIDE OF GUIDANCE IN TAKING THAT ENERGY INTO THE GREAT
LAKES REGION. FOR A NUMBER OF RUNS...IT HAS TRACKED A SFC LOW NE...
ROUGHLY ACROSS THE SE HALF OF LWR MI. THE 00Z ECMWF STARTED TO TREND
SLIGHTLY N AND W WITH TRACK...BUT THE 12Z RUN IS MUCH MORE
SUPPRESSED WITH THE LOW...A RESULT OF THE NE PACIFIC RIDGE BEING
LESS PRONOUNCED WHICH LEADS TO FLATTER DOWNSTREAM FLOW. THERE A FEW
MORE GEM ENSEMBLES SIMILAR TO THE GFS TODAY...BUT THEY ARE STILL A
DEFINITE MINORITY. MUCH WILL DEPEND ON THE STRUCTURE/AMPLITUDE OF
THE NE PACIFIC RIDGE...BUT AT THIS POINT...GIVEN TODAYS AND RECENT
DAYS MEDIUM RANGE GUIDANCE...THE PROBABILITY IS STILL VERY LOW FOR
THE SFC LOW TO TRACK FAR ENOUGH N AND W TO BRING SIGNIFICANT PCPN TO
THE FCST AREA. HOWEVER...AIDED BY NRN STREAM ENERGY...THERE SHOULD
BE SOME -SN ACROSS THE FCST AREA ON SAT ALONG WITH THE POTENTIAL FOR
LAKE ENHANCEMENT NEAR LAKE SUPERIOR. ARCTIC AIR WILL FLOW BACK INTO
THE UPPER LAKES ON SUN...RENEWING LES IN AREAS FAVORED BY NW WINDS.
COLDEST AIR OF THE SEASON COULD FOLLOW FOR MON/TUE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 614 PM EST SUN DEC 28 2014
NORTHWEST FLOW LAKE EFFECT IS TAKING SHAPE OVER WESTERN LAKE
SUPERIOR AND WILL BE THE MAIN ITEM OF CONCERN OVER THE NEXT 24
HOURS. OVERALL...WITH A STRONG INVERSION AROUND 4KFT ABOVE THE
SURFACE...DON/T EXPECT THE SNOW SHOWERS TO BECOME TOO STRONG AND
HAVE KEPT VISIBILITIES IN THE MVFR TO VFR RANGE AT KCMX/KIWD. LOW
LEVEL WINDS DO LOOK TO BACK SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE
TROUGH THAT WILL THEN SHIFT WINDS BACK TO THE NORTHWEST AROUND
DAYBREAK. THUS...HAVE KEPT VSBYS A LITTLE HIGHER AT KIWD WITH THOSE
BACKING WINDS. ONCE THAT WEAK TROUGH MOVES THROUGH...WOULD THINK
THAT LIGHT LAKE EFFECT WOULD MOVE BACK INTO THE SITE.
OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION FOR KSAW...VFR WILL
CONTINUE THROUGH THE PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 216 PM EST SUN DEC 28 2014
AS THE SURFACE TROUGH THAT SLID SOUTHEAST ACROSS LAKE SUPERIOR THIS
MORNING CONTINUES SOUTHEAST THROUGH THE LOWER GREAT
LAKES...PERSISTENT NORTHWEST WINDS OF 15-25KTS ARE EXPECTED OVER
THE LAKE THROUGH TUESDAY. THIS IS DUE TO THE AREA BEING BETWEEN A
STRONG HIGH MOVING INTO THE NORTHERN/CENTRAL PLAINS AND A LOW NEAR
HUDSON BAY. A SURFACE TROUGH WILL SWEEP ACROSS LAKE SUPERIOR ON
WEDNESDAY NIGHT AND TIGHTEN THE PRESSURE GRADIENT ACROSS THE LAKE.
THIS IS EXPECTED TO PRODUCE WESTERLY GALES OF 35-40KTS WEDNESDAY
INTO THURSDAY MORNING.
WITH MUCH COLDER TEMPERATURES MOVING OVER LAKE SUPERIOR OVER THE
NEXT SEVERAL DAYS...FREEZING SPRAY IS POSSIBLE FOR MUCH OF THE
PERIOD. WITH THE STRONGER WINDS TUESDAY NIGHT INTO THURSDAY...HEAVY
FREEZING SPRAY IS EXPECTED OVER MUCH OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1252 PM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 939 AM EST SAT DEC 27 2014
DIFFICULT HEADLINE DECISION THIS MORNING AS THERE WILL LIKELY BE A
SWATH OF SNOWFALL AMOUNTS RIGHT AROUND OUR 6IN/12HR CRITERIA OVER
CENTRAL UPPER MICHIGAN. BELIEVE THE SNOWFALL AMOUNTS THAT WE HAVE
IN THE FORECAST ARE IN LINE FOR WHAT IS EXPECTED WITH THIS LAST
AREA OF SNOW THAT WILL MOVE THROUGH THIS MORNING. THAT AREA WITH
THE FORECASTED HIGHEST AMOUNTS IS IN LINE WITH THE AREA OF RAPIDLY
COOLING CLOUD TOPS OVER CENTRAL UPPER MICHIGAN AND NORTHEAST
WISCONSIN AND MATCHES THE LATEST QPF AMOUNTS FROM THE RAP/HRRR. ON
THE WESTERN EDGE OF THIS SWATH (IRON/DICKINSON COUNTIES)...THEY HAVE
RECEIVED 2.5-3.5 INCHES OF SNOW THUS FAR OVER 9-10 HOURS AND WILL
RECEIVE ANOTHER 2-3 INCHES OVER THE NEXT 3-4HRS WHICH PUTS THEM ON
THE EDGE OF THE CRITERIA. FARTHER EAST...AMOUNTS HAVE BEEN LOWER AND
IN THE 1-2.5 INCH RANGE...BUT THEY WILL LIKELY SEE THE GREATEST
AMOUNTS OF 3.5-5 INCHES. THIS ALSO PUTS THOSE AREAS RIGHT AROUND THE
6 INCH CRITERIA. FEEL THE MOST CONFIDENT ON AMOUNTS JUST OVER
WARNING CRITERIA FROM NORTHERN DICKINSON THROUGH THE SOUTHEAST HALF
OF MARQUETTE AND WESTERN ALGER COUNTY...BUT NOT SURE IF THE UPGRADE
WITH ANOTHER 3-4HRS OF SNOW LEFT IS WORTH THE HEADLINE CHANGE. IN
ADDITION...THE OVERALL WORDING WILL STAY THE SAME. THUS...WILL
UPDATE THE WSW TO HIGHLIGHT THE HEAVIER SNOW OVER THE NEXT FEW HOURS
AND KEEP THE ADVISORIES AS IS...ESPECIALLY SINCE WEBCAMS SHOW MANY
LOCATIONS EAST OF A MARQUETTE TO IRON MOUNTAIN LINE STILL HAVING
MAINLY WET ROADS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1250 PM EST SAT DEC 27 2014
THE SYSTEM LEADING TO THE MODERATE SNOW ACROSS MUCH OF UPPER
MICHIGAN WILL BE QUICKLY LIFTING NORTHEAST AND OUT OF THE AREA OVER
THE NEXT COUPLE OF HOURS. HAVE ALREADY SEEN VISIBILITIES COMING UP
AT KIWD AS THE BACK EDGE OF THE SNOW IS DEPARTING. THAT WEST TO
EAST DIMINISHING TREND WILL CONTINUE AT ALL THREE SITES AND EXPECT
WINDS TO BACK TO THE WEST-NORTHWEST INTO THE EVENING. THIS SHOULD
LEAD TO A TREND TOWARDS VFR AT KIWD/KSAW...BUT KCMX MAY TRY TO HOLD
ONTO HIGH END MVFR THIS EVENING WITH SOME LAKE ENHANCED CLOUDS.
FOCUS THEN TURNS TO A SECOND TROUGH THAT WILL DROP ACROSS WESTERN
LAKE SUPERIOR LATE TONIGHT AND UPPER MICHIGAN ON SUNDAY. JUST AHEAD
OF THIS TROUGH...EXPECT LAKE EFFECT SNOW TO DEVELOP IN THE WESTERLY
WINDS AND AFFECT KCMX SHORTLY AFTER MIDNIGHT. THIS WILL LEAD TO A
PERIOD OF MODERATE SNOWFALL AND HAVE BROUGHT VSBYS BELOW ALTERNATE
LANDING MINS. ONCE THE TROUGH MOVES THROUGH...CONDITIONS WILL
BECOME LESS FAVORABLE AT KCMX AS WINDS TURN TO THE NORTHWEST BUT
BRING A BETTER OPPORTUNITY FOR SNOW AT KIWD. AT KSAW...EXPECT THE
VFR CONDITIONS TO REMAIN THROUGH MUCH OF THE MORNING...BUT BLOWOFF
FROM THE UPSTREAM LAKE EFFECT WILL LIKELY BRING SOME LIGHT SNOW
SHOWERS AND BORDERLINE MVFR/VFR CEILINGS AROUND NOON ON SUNDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...SRF
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1230 PM EST SAT DEC 27 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 AM EST SAT DEC 27 2014
WE WILL SEE THE LAST OF THE MILD WEATHER TODAY WITH INTERMITTENT
LIGHT RAIN AND DRIZZLE. COLDER AIR MOVES IN TONIGHT WITH A SECOND
WAVE OF ARCTIC AIR MONDAY NIGHT THROUGH WEDNESDAY. HIGHS ONLY IN THE 20S
ARE EXPECTED DURING THE MIDDLE PORTION OF THE WEEK AND MAY
STRUGGLE TO REACH 20 DEGREES ON WEDNESDAY...ESPECIALLY NORTH OF GRAND
RAPIDS. SNOW ACCUMULATIONS ALSO APPEAR POSSIBLE MONDAY NIGHT INTO
WEDNESDAY. TEMPERATURES WILL MODERATE SLIGHTLY TOWARD THE END OF
THE WORK WEEK BEFORE ANOTHER SURGE OF ARCTIC AIR NEXT WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
TEMPERATURES HAD RISEN INTO THE MID 40S MAINLY ALONG AND SOUTH OF
I-96 AS OF THIS WRITING. TEMPS AND DEWPOINTS WILL CONTINUE TO
CREEP UP THIS MORNING. 06Z HRRR CONTINUES TO INDICATE PERIODS OF
LIGHT RAIN AND DRIZZLE TODAY...THE FIRST AFTER 10Z OR SO.
THE WEAK SURFACE LOW IS FORECAST TO DEEPEN TO AROUND 1008 MB OVER
NORTHERN LOWER MI BY 18Z. THE COLD FRONT THEN MOVES THROUGH
FOLLOWED BY A VEERING OF THE WINDS DURING THE AFTERNOON. SURFACE
TEMPS ARE EXPECTED TO REMAIN ABOVE FREEZING AT 00Z THIS
EVENING...AND MOISTURE QUICKLY BAILS AFTER 00Z. THE ONSHORE FLOW
IS ALSO SLIGHTLY DIVERGENT. FORECAST THINKING HAS NOT
CHANGED...LITTLE IF ANY SNOW TONIGHT.
QUIET WEATHER EXPECTED ON SUNDAY. A VERY STRONG 1057 MB HIGH
DEVELOPS OVER WESTERN CANADA AND AN EXTENSION OF THIS HIGH
PRESSURE SYSTEM TURNS LOW LEVEL FLOW NORTHEASTERLY BY MONDAY.
THINKING PARTLY SUNNY FOR NOW WITH HIGHS IN THE LOW TO MID 30S.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
MODELS ARE IN DECENT AGREEMENT IN SHOWING A DEEPENING UPPER LOW OVER
HUDSON BAY AS WE HEAD THROUGH THE EXTENDED PERIOD. THIS WILL RESULT
IN A COLDER THAN NORMAL PERIOD THROUGH THE LONG TERM PERIOD.
THE ARCTIC AIR WILL ARRIVE IN WAVES. MONDAY NIGHT THROUGH WEDNESDAY
WILL FEATURE COLD AIR ADVECTION. THE LOW LEVEL THERMAL TROUGH
PUSHES THROUGH ON WEDNESDAY. HIGHS ON WEDNESDAY MAY STRUGGLE TO
REACH 20 DEGREES...ESPECIALLY NORTH OF GRAND RAPIDS. WIND WILL
ACCOMPANY THIS ARCTIC AIRMASS AND SUB ZERO WIND CHILLS WILL OCCUR AT
TIMES. ALSO MODELS HAVE BEEN TRENDING TOWARD MORE MOISTURE IN THE
DGZ MON NIGHT INTO WED. THUS WE MAY END UP WITH SOME
ACCUMULATIONS. I DID TREND POPS UPWARD BASED ON THE TRENDS.
TEMPERATURES ARE LIKELY TO MODERATE SLIGHTLY THURSDAY INTO FRIDAY AS
WARM AIR ADVECTION DEVELOPS ON THE BACKSIDE OF THE DEPARTING
HIGH. THEY ARE EXPECTED TO STILL AVERAGE OUT BELOW NORMAL.
ANOTHER SURGE OF ARCTIC AIR WILL LIKELY PUSH IN OVER NEXT WEEKEND.
THIS IS WHEN THE SOUTHERN ROCKIES LOW KICKS OUT INTO THE PLAINS AND
TRACKS TO THE CENTRAL APPALACHIANS. AS THIS WAVE TRACKS EAST...AN
IMPRESSIVE SURGE OF ARCTIC AIR SINKS SOUTH THROUGH THE GREAT LAKES
REGION. THERE IS A RISK FOR SNOW ASSOCIATED WITH THE ARRIVAL OF
THIS NEXT REINFORCING SHOT OF ARCTIC AIR. OVERALL MODELS HAVE COME
INTO BETTER AGREEMENT OF THE TIMING AND DURATION OF THIS NEXT ARCTIC
AIRMASS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1230 PM EST SAT DEC 27 2014
IFR AND LOWER CONDITIONS ARE CURRENTLY IN PLACE AT ALL OF THE
TERMINALS ACROSS SW LOWER MICHIGAN EARLY AFTERNOON. THIS IS MAINLY
DUE TO LOW CLOUDS IN PLACE AND DUE TO DRIZZLE/FOG WITH A FEW
SHOWERS AROUND. WE EXPECT THE LOW CONDITIONS TO HOLD ON FOR A FEW
HOURS BEFORE CIGS LIFT AND VSBYS IMPROVE TO MVFR FROM WEST TO EAST LIKE
WHAT IS CURRENTLY HAPPENING UPSTREAM ACROSS WI AND IL. THE BETTER
CONDITIONS APPEAR TO BE OCCURRING AFTER THE PASSAGE OF THE COLD FRONT.
THE AREA WILL REMAIN UNDER MVFR CONDITIONS FOR MOST OF THE NIGHT
WITH CIGS OF AROUND 1500 FT EXPECTED. THESE CLOUDS SHOULD TEND TO
BREAK UP BY MID-LATE SUN MORNING AS HIGH PRESSURE BUILDS IN ACROSS
THE AREA.
&&
.MARINE...
ISSUED AT 328 AM EST SAT DEC 27 2014
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR 11 AM TODAY THROUGH 11
AM SUNDAY. AS THE SURFACE LOW APPROACHES...SOUTHERLY WINDS WILL
INCREASE TO 15 TO 25 KNOTS TODAY. WINDS WILL VEER WEST TO 30 KNOTS
LATE THIS AFTERNOON AND EVENING. WAVES WILL BUILD TO 4 TO 8 FEET
NORTH OF HOLLAND AND 3 TO 5 FEET SOUTH OF HOLLAND. WEST WINDS WILL
VEER NORTHWESTERLY TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST SAT DEC 27 2014
AROUND A TENTH OF AN INCH OR LESS OF RAINFALL IS EXPECTED
TODAY...WITH SLIGHTLY HIGHER AMOUNTS POSSIBLE TOWARD LUDINGTON.
THIS LIGHT RAINFALL IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT
ON RIVERS. ALL RIVER FLOOD ADVISORIES HAVE BEEN CANCELED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST SUNDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...EBW
SHORT TERM...EBW
LONG TERM...MJS
AVIATION...NJJ
HYDROLOGY...EBW
MARINE...EBW
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
940 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 939 AM EST SAT DEC 27 2014
DIFFICULT HEADLINE DECISION THIS MORNING AS THERE WILL LIKELY BE A
SWATH OF SNOWFALL AMOUNTS RIGHT AROUND OUR 6IN/12HR CRITERIA OVER
CENTRAL UPPER MICHIGAN. BELIEVE THE SNOWFALL AMOUNTS THAT WE HAVE
IN THE FORECAST ARE IN LINE FOR WHAT IS EXPECTED WITH THIS LAST
AREA OF SNOW THAT WILL MOVE THROUGH THIS MORNING. THAT AREA WITH
THE FORECASTED HIGHEST AMOUNTS IS IN LINE WITH THE AREA OF RAPIDLY
COOLING CLOUD TOPS OVER CENTRAL UPPER MICHIGAN AND NORTHEAST
WISCONSIN AND MATCHES THE LATEST QPF AMOUNTS FROM THE RAP/HRRR. ON
THE WESTERN EDGE OF THIS SWATH (IRON/DICKINSON COUNTIES)...THEY HAVE
RECEIVED 2.5-3.5 INCHES OF SNOW THUS FAR OVER 9-10 HOURS AND WILL
RECEIVE ANOTHER 2-3 INCHES OVER THE NEXT 3-4HRS WHICH PUTS THEM ON
THE EDGE OF THE CRITERIA. FARTHER EAST...AMOUNTS HAVE BEEN LOWER AND
IN THE 1-2.5 INCH RANGE...BUT THEY WILL LIKELY SEE THE GREATEST
AMOUNTS OF 3.5-5 INCHES. THIS ALSO PUTS THOSE AREAS RIGHT AROUND THE
6 INCH CRITERIA. FEEL THE MOST CONFIDENT ON AMOUNTS JUST OVER
WARNING CRITERIA FROM NORTHERN DICKINSON THROUGH THE SOUTHEAST HALF
OF MARQUETTE AND WESTERN ALGER COUNTY...BUT NOT SURE IF THE UPGRADE
WITH ANOTHER 3-4HRS OF SNOW LEFT IS WORTH THE HEADLINE CHANGE. IN
ADDITION...THE OVERALL WORDING WILL STAY THE SAME. THUS...WILL
UPDATE THE WSW TO HIGHLIGHT THE HEAVIER SNOW OVER THE NEXT FEW HOURS
AND KEEP THE ADVISORIES AS IS...ESPECIALLY SINCE WEBCAMS SHOW MANY
LOCATIONS EAST OF A MARQUETTE TO IRON MOUNTAIN LINE STILL HAVING
MAINLY WET ROADS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 626 AM EST SAT DEC 27 2014
EXPECT IFR/LIFR CONDITIONS THROUGH EARLY AFTERNOON AS LOW PRESSURE
OVER SOUTHERN WI LIFTS NORTHEAST TO NORTHERN LOWER MI THIS AFTERNOON.
THE LOW PRESSURE SYSTEM WILL BRING LIGHT TO MODERATE SNOWFALL ACROSS
WEST-CENTRAL UPPER MICHIGAN THROUGH EARLY THIS AFTERNOON. HAVE SHOWN
LOWERING TREND WITH CEILINGS/VISIBILITIES AS THIS SNOW MOVES
THROUGH...WITH THE WORST CONDITIONS AT KIWD AND ESPECIALLY
KSAW...WHERE CONDITIONS WILL FALL TO OR REMAIN LIFR INTO EARLY AFTERNOON.
THE LOW AND HEAVIER SNOW WILL QUICKLY DEPART NE AS CONDITIONS
IMPROVE TO MVFR BY MID AFTERNOON AND TO VFR SAT EVENING AT KIWD/KSAW.
COLDER AIR MOVING OVER LAKE SUPERIOR TONIGHT IN A WNW FLOW WILL HELP
DEVELOP LAKE EFFECT SNOW AT KCMX AND KIWD LATE SAT NIGHT. CONVERGENT
WESTERLY FLOW AND GUSTIER WINDS DEVELOPING COULD LEAD TO IFR
CONDITIONS AT KCMX IN SNOW/BLOWING SNOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
633 AM EST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 626 AM EST SAT DEC 27 2014
EXPECT IFR/LIFR CONDITIONS THROUGH EARLY AFTERNOON AS LOW PRESSURE
OVER SOUTHERN WI LIFTS NORTHEAST TO NORTHERN LOWER MI THIS AFTERNOON.
THE LOW PRESSURE SYSTEM WILL BRING LIGHT TO MODERATE SNOWFALL ACROSS
WEST-CENTRAL UPPER MICHIGAN THROUGH EARLY THIS AFTERNOON. HAVE SHOWN
LOWERING TREND WITH CEILINGS/VISIBILITIES AS THIS SNOW MOVES
THROUGH...WITH THE WORST CONDITIONS AT KIWD AND ESPECIALLY
KSAW...WHERE CONDITIONS WILL FALL TO OR REMAIN LIFR INTO EARLY AFTERNOON.
THE LOW AND HEAVIER SNOW WILL QUICKLY DEPART NE AS CONDITIONS
IMPROVE TO MVFR BY MID AFTERNOON AND TO VFR SAT EVENING AT KIWD/KSAW.
COLDER AIR MOVING OVER LAKE SUPERIOR TONIGHT IN A WNW FLOW WILL HELP
DEVELOP LAKE EFFECT SNOW AT KCMX AND KIWD LATE SAT NIGHT. CONVERGENT
WESTERLY FLOW AND GUSTIER WINDS DEVELOPING COULD LEAD TO IFR
CONDITIONS AT KCMX IN SNOW/BLOWING SNOW. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
610 AM EST SAT DEC 27 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 AM EST SAT DEC 27 2014
WE WILL SEE THE LAST OF THE MILD WEATHER TODAY WITH INTERMITTENT
LIGHT RAIN AND DRIZZLE. COLDER AIR MOVES IN TONIGHT WITH A SECOND
WAVE OF ARCTIC AIR MONDAY NIGHT THROUGH WEDNESDAY. HIGHS ONLY IN THE 20S
ARE EXPECTED DURING THE MIDDLE PORTION OF THE WEEK AND MAY
STRUGGLE TO REACH 20 DEGREES ON WEDNESDAY...ESPECIALLY NORTH OF GRAND
RAPIDS. SNOW ACCUMULATIONS ALSO APPEAR POSSIBLE MONDAY NIGHT INTO
WEDNESDAY. TEMPERATURES WILL MODERATE SLIGHTLY TOWARD THE END OF
THE WORK WEEK BEFORE ANOTHER SURGE OF ARCTIC AIR NEXT WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
TEMPERATURES HAD RISEN INTO THE MID 40S MAINLY ALONG AND SOUTH OF
I-96 AS OF THIS WRITING. TEMPS AND DEWPOINTS WILL CONTINUE TO
CREEP UP THIS MORNING. 06Z HRRR CONTINUES TO INDICATE PERIODS OF
LIGHT RAIN AND DRIZZLE TODAY...THE FIRST AFTER 10Z OR SO.
THE WEAK SURFACE LOW IS FORECAST TO DEEPEN TO AROUND 1008 MB OVER
NORTHERN LOWER MI BY 18Z. THE COLD FRONT THEN MOVES THROUGH
FOLLOWED BY A VEERING OF THE WINDS DURING THE AFTERNOON. SURFACE
TEMPS ARE EXPECTED TO REMAIN ABOVE FREEZING AT 00Z THIS
EVENING...AND MOISTURE QUICKLY BAILS AFTER 00Z. THE ONSHORE FLOW
IS ALSO SLIGHTLY DIVERGENT. FORECAST THINKING HAS NOT
CHANGED...LITTLE IF ANY SNOW TONIGHT.
QUIET WEATHER EXPECTED ON SUNDAY. A VERY STRONG 1057 MB HIGH
DEVELOPS OVER WESTERN CANADA AND AN EXTENSION OF THIS HIGH
PRESSURE SYSTEM TURNS LOW LEVEL FLOW NORTHEASTERLY BY MONDAY.
THINKING PARTLY SUNNY FOR NOW WITH HIGHS IN THE LOW TO MID 30S.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
MODELS ARE IN DECENT AGREEMENT IN SHOWING A DEEPENING UPPER LOW OVER
HUDSON BAY AS WE HEAD THROUGH THE EXTENDED PERIOD. THIS WILL RESULT
IN A COLDER THAN NORMAL PERIOD THROUGH THE LONG TERM PERIOD.
THE ARCTIC AIR WILL ARRIVE IN WAVES. MONDAY NIGHT THROUGH WEDNESDAY
WILL FEATURE COLD AIR ADVECTION. THE LOW LEVEL THERMAL TROUGH
PUSHES THROUGH ON WEDNESDAY. HIGHS ON WEDNESDAY MAY STRUGGLE TO
REACH 20 DEGREES...ESPECIALLY NORTH OF GRAND RAPIDS. WIND WILL
ACCOMPANY THIS ARCTIC AIRMASS AND SUB ZERO WIND CHILLS WILL OCCUR AT
TIMES. ALSO MODELS HAVE BEEN TRENDING TOWARD MORE MOISTURE IN THE
DGZ MON NIGHT INTO WED. THUS WE MAY END UP WITH SOME
ACCUMULATIONS. I DID TREND POPS UPWARD BASED ON THE TRENDS.
TEMPERATURES ARE LIKELY TO MODERATE SLIGHTLY THURSDAY INTO FRIDAY AS
WARM AIR ADVECTION DEVELOPS ON THE BACKSIDE OF THE DEPARTING
HIGH. THEY ARE EXPECTED TO STILL AVERAGE OUT BELOW NORMAL.
ANOTHER SURGE OF ARCTIC AIR WILL LIKELY PUSH IN OVER NEXT WEEKEND.
THIS IS WHEN THE SOUTHERN ROCKIES LOW KICKS OUT INTO THE PLAINS AND
TRACKS TO THE CENTRAL APPALACHIANS. AS THIS WAVE TRACKS EAST...AN
IMPRESSIVE SURGE OF ARCTIC AIR SINKS SOUTH THROUGH THE GREAT LAKES
REGION. THERE IS A RISK FOR SNOW ASSOCIATED WITH THE ARRIVAL OF
THIS NEXT REINFORCING SHOT OF ARCTIC AIR. OVERALL MODELS HAVE COME
INTO BETTER AGREEMENT OF THE TIMING AND DURATION OF THIS NEXT ARCTIC
AIRMASS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 607 AM EST SAT DEC 27 2014
THE MAIN CHALLENGE IN THE AVIATION FORECAST DEALS WITH THE
POTENTIAL FOR IMPACT CEILINGS AND VISIBILITIES.
WHILE DELAYED...THE IFR IS DEVELOPING OVER IN INDIANA AND
ILLINOIS...AND HAS NOW MOVED INTO THE KBEH REGION. THIS LOW LEVEL
MOISTURE WILL BE TRACKING NORTHWARD INTO SOUTHWEST LOWER MI THIS
MORNING. THE LOW CONDITIONS WILL THEN PERSIST THROUGH MUCH OF THE
AFTERNOON. IMPROVING CONDITIONS ARE FORECASTED FOR LATER TODAY AS
THE WIND VEERS WITH TIME ALLOWING A COLDER/DRIER AIRMASS TO ARRIVE
FROM THE WEST.
&&
.MARINE...
ISSUED AT 328 AM EST SAT DEC 27 2014
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR 11 AM TODAY THROUGH 11
AM SUNDAY. AS THE SURFACE LOW APPROACHES...SOUTHERLY WINDS WILL
INCREASE TO 15 TO 25 KNOTS TODAY. WINDS WILL VEER WEST TO 30 KNOTS
LATE THIS AFTERNOON AND EVENING. WAVES WILL BUILD TO 4 TO 8 FEET
NORTH OF HOLLAND AND 3 TO 5 FEET SOUTH OF HOLLAND. WEST WINDS WILL
VEER NORTHWESTERLY TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST SAT DEC 27 2014
AROUND A TENTH OF AN INCH OR LESS OF RAINFALL IS EXPECTED
TODAY...WITH SLIGHTLY HIGHER AMOUNTS POSSIBLE TOWARD LUDINGTON.
THIS LIGHT RAINFALL IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT
ON RIVERS. ALL RIVER FLOOD ADVISORIES HAVE BEEN CANCELED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 AM EST SUNDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...EBW
SHORT TERM...EBW
LONG TERM...MJS
AVIATION...MJS
HYDROLOGY...EBW
MARINE...EBW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
539 AM EST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1223 AM EST SAT DEC 27 2014
MVFR CIGS WILL GIVE WAY TO IFR/LIFR CONDITIONS BY LATE TONIGHT OR
EARLY SATURDAY AS LOW PRESSURE OVER SE IA LIFTS NORTHEAST TO NORTHERN
LOWER MI SAT AFTERNOON. THE LOW PRESSURE SYSTEM WILL BRING LIGHT TO
OCCASIONALLY MODERATE SNOWFALL ACROSS WEST-CENTRAL UPPER MICHIGAN
OVERNIGHT THROUGH SATURDAY MORNING. HAVE SHOWN LOWERING
CEILINGS/VISIBILITIES AS THIS SNOW MOVES THROUGH...WITH THE WORST
CONDITIONS AT KIWD AND ESPECIALLY KSAW...WHERE CONDITIONS WILL FALL
TO OR REMAIN LIFR. THE LOW AND HEAVIER SNOW WILL QUICKLY DEPART
SATURDAY AFTERNOON AND LEAD TO IMPROVING CONDITIONS TO MVFR THE
AFTERNOON AND TO VFR SAT EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
328 AM EST SAT DEC 27 2014
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 328 AM EST SAT DEC 27 2014
WE WILL SEE THE LAST OF THE MILD WEATHER TODAY WITH INTERMITTENT
LIGHT RAIN AND DRIZZLE. COLDER AIR MOVES IN TONIGHT WITH A SECOND
WAVE OF ARCTIC AIR MONDAY NIGHT THROUGH WEDNESDAY. HIGHS ONLY IN THE 20S
ARE EXPECTED DURING THE MIDDLE PORTION OF THE WEEK AND MAY
STRUGGLE TO REACH 20 DEGREES ON WEDNESDAY...ESPECIALLY NORTH OF GRAND
RAPIDS. SNOW ACCUMULATIONS ALSO APPEAR POSSIBLE MONDAY NIGHT INTO
WEDNESDAY. TEMPERATURES WILL MODERATE SLIGHTLY TOWARD THE END OF
THE WORK WEEK BEFORE ANOTHER SURGE OF ARCTIC AIR NEXT WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
TEMPERATURES HAD RISEN INTO THE MID 40S MAINLY ALONG AND SOUTH OF
I-96 AS OF THIS WRITING. TEMPS AND DEWPOINTS WILL CONTINUE TO
CREEP UP THIS MORNING. 06Z HRRR CONTINUES TO INDICATE PERIODS OF
LIGHT RAIN AND DRIZZLE TODAY...THE FIRST AFTER 10Z OR SO.
THE WEAK SURFACE LOW IS FORECAST TO DEEPEN TO AROUND 1008 MB OVER
NORTHERN LOWER MI BY 18Z. THE COLD FRONT THEN MOVES THROUGH
FOLLOWED BY A VEERING OF THE WINDS DURING THE AFTERNOON. SURFACE
TEMPS ARE EXPECTED TO REMAIN ABOVE FREEZING AT 00Z THIS
EVENING...AND MOISTURE QUICKLY BAILS AFTER 00Z. THE ONSHORE FLOW
IS ALSO SLIGHTLY DIVERGENT. FORECAST THINKING HAS NOT
CHANGED...LITTLE IF ANY SNOW TONIGHT.
QUIET WEATHER EXPECTED ON SUNDAY. A VERY STRONG 1057 MB HIGH
DEVELOPS OVER WESTERN CANADA AND AN EXTENSION OF THIS HIGH
PRESSURE SYSTEM TURNS LOW LEVEL FLOW NORTHEASTERLY BY MONDAY.
THINKING PARTLY SUNNY FOR NOW WITH HIGHS IN THE LOW TO MID 30S.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
MODELS ARE IN DECENT AGREEMENT IN SHOWING A DEEPENING UPPER LOW OVER
HUDSON BAY AS WE HEAD THROUGH THE EXTENDED PERIOD. THIS WILL RESULT
IN A COLDER THAN NORMAL PERIOD THROUGH THE LONG TERM PERIOD.
THE ARCTIC AIR WILL ARRIVE IN WAVES. MONDAY NIGHT THROUGH WEDNESDAY
WILL FEATURE COLD AIR ADVECTION. THE LOW LEVEL THERMAL TROUGH
PUSHES THROUGH ON WEDNESDAY. HIGHS ON WEDNESDAY MAY STRUGGLE TO
REACH 20 DEGREES...ESPECIALLY NORTH OF GRAND RAPIDS. WIND WILL
ACCOMPANY THIS ARCTIC AIRMASS AND SUB ZERO WIND CHILLS WILL OCCUR AT
TIMES. ALSO MODELS HAVE BEEN TRENDING TOWARD MORE MOISTURE IN THE
DGZ MON NIGHT INTO WED. THUS WE MAY END UP WITH SOME
ACCUMULATIONS. I DID TREND POPS UPWARD BASED ON THE TRENDS.
TEMPERATURES ARE LIKELY TO MODERATE SLIGHTLY THURSDAY INTO FRIDAY AS
WARM AIR ADVECTION DEVELOPS ON THE BACKSIDE OF THE DEPARTING
HIGH. THEY ARE EXPECTED TO STILL AVERAGE OUT BELOW NORMAL.
ANOTHER SURGE OF ARCTIC AIR WILL LIKELY PUSH IN OVER NEXT WEEKEND.
THIS IS WHEN THE SOUTHERN ROCKIES LOW KICKS OUT INTO THE PLAINS AND
TRACKS TO THE CENTRAL APPALACHIANS. AS THIS WAVE TRACKS EAST...AN
IMPRESSIVE SURGE OF ARCTIC AIR SINKS SOUTH THROUGH THE GREAT LAKES
REGION. THERE IS A RISK FOR SNOW ASSOCIATED WITH THE ARRIVAL OF
THIS NEXT REINFORCING SHOT OF ARCTIC AIR. OVERALL MODELS HAVE COME
INTO BETTER AGREEMENT OF THE TIMING AND DURATION OF THIS NEXT ARCTIC
AIRMASS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1157 PM EST FRI DEC 26 2014
CEILINGS WILL SLOWLY LOWER TO IFR BY MORNING AND PERIOD OF LIGHT
RAIN OR DRIZZLE WILL ALSO DEVELOP BY THEN ALSO LOWERING
VISIBILITIES TO IFR. THE FRONT WILL COME THROUGH DURING THE
AFTERNOON AND WILL END THE PRECIPITATION AND IMPROVE VISIBILITIES.
CEILINGS WILL ONLY SLOWLY LIFT DURING THE EVENING.
&&
.MARINE...
ISSUED AT 328 AM EST SAT DEC 27 2014
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR 11 AM TODAY THROUGH 11
AM SUNDAY. AS THE SURFACE LOW APPROACHES...SOUTHERLY WINDS WILL
INCREASE TO 15 TO 25 KNOTS TODAY. WINDS WILL VEER WEST TO 30 KNOTS
LATE THIS AFTERNOON AND EVENING. WAVES WILL BUILD TO 4 TO 8 FEET
NORTH OF HOLLAND AND 3 TO 5 FEET SOUTH OF HOLLAND. WEST WINDS WILL
VEER NORTHWESTERLY TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST SAT DEC 27 2014
AROUND A TENTH OF AN INCH OR LESS OF RAINFALL IS EXPECTED
TODAY...WITH SLIGHTLY HIGHER AMOUNTS POSSIBLE TOWARD LUDINGTON.
THIS LIGHT RAINFALL IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT
ON RIVERS. ALL RIVER FLOOD ADVISORIES HAVE BEEN CANCELED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 AM EST SUNDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...EBW
SHORT TERM...EBW
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...EBW
MARINE...EBW
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1158 PM EST FRI DEC 26 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 PM EST FRI DEC 26 2014
ONE MORE UNSEASONABLY MILD DAY IS IN STORE FOR SATURDAY AS A LOW
PRESSURE SYSTEM OVER MISSOURI TRACKS NORTHEAST THROUGH WISCONSIN AND
NORTHERN MICHIGAN.
MOISTURE STREAMING NORTH AHEAD OF THIS SYSTEM WILL BRING CLOUDS AND
OCCASIONAL LIGHT RAIN OR DRIZZLE BEGINNING LATE TONIGHT AND
CONTINUING THROUGH SATURDAY. THE RAIN MAY MIX WITH A LITTLE LIGHT
SNOW SATURDAY NIGHT BEFORE ENDING AS A COLD FRONT PASSES THROUGH.
WE WILL SEE SOME CHILLY AIR AND LIGHT LAKE EFFECT SNOW SHOWERS
ARRIVE THIS WEEK WITH HIGHS MAINLY IN THE 20S. NO SIGNIFICANT SNOW
ACCUMULATIONS ARE EXPECTED AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 330 PM EST FRI DEC 26 2014
NO MAJOR CHANGES IN THINKING TO THE GOING FORECAST. WIDESPREAD LOW
CLOUDS DEVELOP LATER THIS EVENING AS SFC DEW POINTS AROUND 40 STREAM
IN FROM THE SOUTHWEST. LATEST RUNS OF THE HRRR SHOW SCATTERED LIGHT
CONVECTIVE LOOKING RAIN SHOWERS DEVELOPING THIS EVENING ACROSS
MISSOURI AND ILLINOIS. THESE SHOULD WILL LIKELY TRACK INTO THE AREA
FROM THE SOUTHWEST OR DEVELOP OVERHEAD OVERNIGHT AND PERSIST
SATURDAY WITHIN THE WARM ADVECTION ZONE AHEAD OF THE APPROACHING SFC
LOW AND COLD FRONT. IN ADDITION TO THE CONVECTIVE RAIN SHOWERS...
SOME PATCHY DRIZZLE MAY BE SQUEEZED OUT OF THE LOW CLOUDS AT TIMES
LATE TONIGHT AND SATURDAY.
DEEPER MOISTURE MOVES EAST OF THE AREA AFTER 00Z SUNDAY ABOUT THE
TIME THE COLDER AIR IS ARRIVING. PRECIPITATION BEHIND THE SFC COLD
FRONT SHOULD TREND TOWARD JUST SOME VERY LIGHT MIXED RAIN AND SNOW
SHOWERS. NO SNOW ACCUMULATIONS EXPECTED LATE SATURDAY NIGHT INTO
EARLY SUNDAY DUE TO VERY SHALLOW MOISTURE PROFILES AND QUESTIONABLE
DGZ SATURATION. ADDITIONALLY...SURFACE RIDGING/ANTICYCLONIC FLOW IS
QUICK TO BUILD IN WHICH ACTUALLY LEADS TO DECENT PROSPECT FOR
SUNSHINE DEVELOPING SUNDAY AFTERNOON.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 330 PM EST FRI DEC 26 2014
WE CONTINUE TO EXPECT A TREND TOWARD COLDER WEATHER IN THE LONG TERM
WITH CHCS OF SNOW SHOWERS THROUGH THE PERIOD. SNOW ACCUMULATIONS DO
NOT LOOK TO BE ANYTHING SIGNIFICANT IN THE FCST PERIOD FOR NOW. WE
WILL CONTINUE TO MONITOR THIS POTENTIAL AS IT WOULD NOT TAKE MAJOR
CHANGES TO BRING A BETTER POTENTIAL OF LAKE EFFECT.
THE CHC OF SNOW FOR SW LOWER ON MON DOES NOT LOOK REAL GOOD AT THIS
TIME. A SHORT WAVE TROUGH WILL BE MOVING INTO THE GREAT LAKES REGION
FROM THE WNW ON MON. HOWEVER A STRONG 1050+ MB RIDGE TO OUR WEST
WILL BE IN CONTROL OF THE LOWER LEVELS HERE. NE FLOW AND AN
EXTENSION OF THE SFC RIDGE IN PLACE WILL LIMIT PCPN POTENTIAL.
THE PERIOD FROM TUE THROUGH THU THEN WILL FEATURE THE COLDEST TEMPS
OF THE LONG TERM. THE MON SHORT WAVE WILL COMPLETE THE TRANSITION OF
THE UPPER AIR PATTERN TO MORE OF A NW FLOW ALOFT OVER THE AREA.
COLDER AIR WILL CONTINUE TO FILTER IN ON THE NRLY AND EVENTUALLY NW
LOW LEVEL FLOW. THE AIR WILL BE PLENTY COLD ENOUGH FOR LAKE
EFFECT...HOWEVER WE WILL REMAIN ON THE SOUTH SIDE OF THE NRN BRANCH
OF THE JET. SHORT WAVES DIVING SE ARE EXPECTED TO REMAIN JUST NORTH
OF THE CWFA. THIS WILL LIMIT MOISTURE DEPTH SIGNIFICANTLY AND ALSO
THE DEEP LAYER INSTABILITY.
LAKE EFFECT COULD BE MORE ROBUST IF THE UPPER JET AND THE ASSOCIATED
SHORT WAVES ARE ABLE TO DIVE JUST A LITTLE FURTHER SOUTH. WE BELIEVE
THAT THE STRONG CUTOFF UPPER LOW ACROSS THE SW U.S. AND THE RIDGE
AHEAD OF IT WILL HOLD THE NRN BRANCH OF THE JET JUST NORTH OF THE
AREA.
WE COULD SEE THE INITIAL EFFECTS OF THE CUTOFF UPPER LOW START TO
MOVE IN AS EARLY AS NEXT FRI AS WARM AND MOISTURE ADVECTION AHEAD OF
IT STARTS TO OVERRUN THE COLDER AIR EXPECTED TO BE IN PLACE. THE
MODELS TYPICALLY EJECT THESE SYSTEMS OUT TOO QUICK...SO WE WILL KEEP
THE CHC OF PCPN LOW AT THIS TIME FOR NEXT FRI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1157 PM EST FRI DEC 26 2014
CEILING WILL SLOWLY LOWER TO IFR BY MORNING AND PERIOD OF LIGHT
RAIN OR DRIZZLE WILL ALSO DEVELOP BY THEN ALSO LOWERING
VISIBILITIES TO IFR. THE FRONT WILL COME THROUGH DURING THE
AFTERNOON AND WILL END THE PRECIPITATION AND IMPROVE VISIBILITIES.
CEILINGS WILL ONLY SLOWLY LIFT DURING THE EVENING.
&&
.MARINE...
ISSUED AT 330 PM EST FRI DEC 26 2014
THE PRESSURE GRADIENT RELAXES TONIGHT SO WINDS AND WAVES ARE
EXPECTED TO SUBSIDE. HOWEVER THEY WILL RAMP UP AGAIN LATE SATURDAY
AND SATURDAY NIGHT AS A COLD FRONT PASSES ACROSS LK MI.
&&
.HYDROLOGY...
ISSUED AT 330 PM EST FRI DEC 26 2014
HAVE CANCELED THE ADVISORY FOR THE MAPLE RIVER AT MAPLE RAPIDS AS
LATEST FORECAST HAS IT CRESTING A HALF FOOT BELOW BANKFULL SUNDAY.
SYCAMORE CREEK AT HOLT CRESTED LAST NIGHT AND IS FALLING BELOW
BANKFULL AT THIS TIME. ABOUT A TENTH OF AN INCH OF PRECIPITATION IS
EXPECTED ON SATURDAY WHICH WILL NOT AFFECT THE RIVERS MUCH. A LACK
OF SIGNIFICANT PRECIPITATION INTO THE NEW YEAR WILL ALLOW THE LARGER
RIVERS TIME TO CREST AND FALL WITHOUT MUCH IMPACT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...WDM
HYDROLOGY...CAS
MARINE...MEADE
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1210 PM CST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST SAT DEC 27 2014
AFTER TAKING MOST OF DECEMBER OFF...THE SHORT TERM PERIOD MARKS THE
BEGINNING OF THE RETURN OF WEATHER THAT IS MORE TYPICAL OF WHAT WE
WOULD EXPECT IN THE HEART OF WINTER...AT LEAST FOR TEMPERATURES.
FEATURE DRIVING SNOW ACROSS THE AREA THIS MORNING SHOWS UP WELL ON
SATELLITE WITH A NICE SWIRL MOVING INTO THE SIOUX FALLS AREA...WITH
A NICE DRY SLOT NOSING INTO SE MN. THIS DRY SLOT IS ASSOCIATED WITH
A TROWAL...WHICH HAS HELPED FORCE A NICE DEFORMATION BAND OF PRECIP
TO THE NW OF IT. MODELS GOING BACK TO THE 00Z RUNS LAST NIGHT HAVE
ACTUALLY DONE A GOOD JOB HANDLING THIS SNOW AND PRETTY MUCH FOLLOWED
THE HOPWRF AND HRRR FOR ENDING SNOW ACROSS THE AREA THIS MORNING.
EVERYTHING APPEARS ON TRACK FOR A HEALTHY SWATH OF 3 TO 5 INCHES.
BACK TO THE WEST OF THIS LOW...THERE IS A RIDGE AXIS EXTENDING FROM
ERN COLORADO UP INTO THE ERN DAKOTAS. TEMPS AND DEWPS FALL OFF TO
WITHIN 10 DEGS OF EITHER SIDE OF ZERO WITHIN THE RIDGE AXIS...THOUGH
THIS RIDGE AXIS ALSO HAS WHAT HAS BEEN A RARITY THIS MONTH...MOSTLY
CLEAR SKIES. ITS LOOKING LIKE GOOD BET FOR SEEING SOME SUN TODAY
WEST OF I-35. EAST OF I-35...THE CLEARING WILL BE RACING
SUNSET...THOUGH BY THE TIME YOU GET TO EAU CLAIRE...IT`S A PRETTY
GOOD BET THAT SKIES WILL REMAIN OVERCAST THROUGH THE DURATION OF
DAYLIGHT HOURS. THESE MAINLY CLEAR SKIES MAY CAUSE TEMPERATURES TO
BE A BIT COOLER THAN WHAT IS CURRENTLY FORECAST TONIGHT...ESPECIALLY
WHERE WE ARE SEEING SNOW RIGHT NOW FROM SOUTHERN MN INTO WRN WI. OF
COURSE OUR TIME WITH CLEARISH SKIES WILL BE SHORT LIVED...AS BY 12Z
SUNDAY...THE ARCTIC BOUNDARY WILL BE SLIPPING INTO CENTRAL MN...WITH
CLOUD COVER INCREASING AHEAD OF THE FRONT AS IT DROPS SOUTH ACROSS
NRN MN THROUGH THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 329 AM CST SAT DEC 27 2014
THE MAIN HIGHLIGHT OF THE LONG TERM FORECAST PERIOD WILL BE THE
RETURN TO BELOW NORMAL TEMPERATURES BEFORE WE RING IN THE NEW
YEAR. OTHER THAN A SLIM CHANCE FOR SNOWFALL ON SUNDAY NIGHT INTO
MONDAY AS THE ARCTIC BOUNDARY RESPONSIBLE FOR THE AFOREMENTIONED
COOL DOWN IN TEMPERATURES MOVES THROUGH...DRY WEATHER IS EXPECTED
UNTIL POSSIBLY NEXT FRIDAY.
SUNDAY WILL LIKELY BE THE ONE AND ONLY MILD DAY THROUGH MOST OF
THE UPCOMING WEEK IN ADVANCE OF THE COLD FRONT. MODEL AGREEMENT WITH
THIS FEATURE HAS NOT REALLY SHOWN MUCH IMPROVEMENT OVER THE LAST
24 HOURS. THE ECMWF HAS BEEN FAIRLY INSISTENT THAT THE FORECAST
AREA WILL MISS OUT ON SNOWFALL WITH THIS FEATURE...WHILE THE
SREF...NAM...AND NOW 27.00 GFS THINK SOUTHERN MN WILL SEE A 1-3
INCH SNOWFALL ON SUNDAY NIGHT AND MONDAY MORNING. SINCE THE ECMWF
IS A BIT OF AN OUTLIER FROM THE OVERALL MODEL CONSENSUS SOLUTION...WHICH
HAS SHOWN UP FOR MULTIPLE RUNS...HAVE INCLUDED 30 POPS FOR 00Z-18Z
MONDAY GENERALLY SOUTH OF INTERSTATE 94. HAVE HOWEVER KEPT SNOWFALL
ACCUMULATIONS AROUND ONE INCH OR LESS WITH THE THOUGHT THE
FORCING/MOISTURE MIGHT BE WEAKER/LOWER THAN PROGGED BY THE
CONSENSUS.
WHILE CONFIDENCE IS RATHER LOW WITH RESPECT TO SNOWFALL CHANCES AS
THIS BOUNDARY SURGES ACROSS THE AREA...WHAT IS MORE CERTAIN IS
THAT A BLAST OF COLDER AIR WILL FOLLOW IN ITS WAKE. THERE IS STILL
FINE AGREEMENT THAT H85 TEMPERATURES WILL REDUCE TO -18C TO -20C
BY TUESDAY. SUB-ZERO LOWS FOR TUESDAY AND WEDNESDAY MORNINGS ARE
FAIRLY CERTAIN...ALONG WITH HIGHS IN THE SINGLE DIGITS TO LOW
TEENS. WIND CHILLS WILL SNEAK TO AROUND -20F TO -30F ON MONDAY
NIGHT AND TUESDAY NIGHT...BUT MODERATE A TAD /-10F/ FOR NEW YEARS
EVE AS LOW TEMPERATURES RECOVER TO ABOVE ZERO VALUES.
AT THE END OF THE UPCOMING WEEK...GFS AND ECMWF MODELS FORECAST ANOTHER
WAVE TO DROP SOUTH FROM CANADA...THIS TIME THROUGH THE BASE OF A
HUDSON/JAMES BAY CYCLONE. WHILE TIMING/AMPLITUDE DETAILS ARE A BIT
UP IN THE AIR AT THIS POINT...THE PROGS DO WARRANT INCLUSION OF
20-30 POPS FOR SNOW ON FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1202 PM CST SAT DEC 27 2014
VFR IS IN PLACE FOR MOST OF MN AT TAF ISSUANCE TIME...WITH THE
BACK EDGE OF THE STRATUS NEARING MSP. THE CLEARING WILL PUSH
OVER THE WI TAF SITES THROUGH MID AFTERNOON. NORTHWEST WINDS WILL
BACK SOUTHWEST THIS EVENING...THEN BECOME NORTHWEST AGAIN SUNDAY
BEHIND A COLD FRONT.
KMSP...MVFR CIGS EXPECTED UNTIL ABOUT 19Z...THEN VFR THROUGH MUCH
OF THE PERIOD. COULD SEE SOME MVFR CIGS RETURN SUNDAY AFTERNOON.
/OUTLOOK FOR KMSP/
SUN NIGHT...MVFR POSSIBLE EARLY. WINDS N 5-10 KTS.
MON...VFR. WINDS N 10 KTS.
TUE...VFR. WINDS NW 5-10 KTS
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
558 AM CST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST SAT DEC 27 2014
AFTER TAKING MOST OF DECEMBER OFF...THE SHORT TERM PERIOD MARKS THE
BEGINNING OF THE RETURN OF WEATHER THAT IS MORE TYPICAL OF WHAT WE
WOULD EXPECT IN THE HEART OF WINTER...AT LEAST FOR TEMPERATURES.
FEATURE DRIVING SNOW ACROSS THE AREA THIS MORNING SHOWS UP WELL ON
SATELLITE WITH A NICE SWIRL MOVING INTO THE SIOUX FALLS AREA...WITH
A NICE DRY SLOT NOSING INTO SE MN. THIS DRY SLOT IS ASSOCIATED WITH
A TROWAL...WHICH HAS HELPED FORCE A NICE DEFORMATION BAND OF PRECIP
TO THE NW OF IT. MODELS GOING BACK TO THE 00Z RUNS LAST NIGHT HAVE
ACTUALLY DONE A GOOD JOB HANDLING THIS SNOW AND PRETTY MUCH FOLLOWED
THE HOPWRF AND HRRR FOR ENDING SNOW ACROSS THE AREA THIS MORNING.
EVERYTHING APPEARS ON TRACK FOR A HEALTHY SWATH OF 3 TO 5 INCHES.
BACK TO THE WEST OF THIS LOW...THERE IS A RIDGE AXIS EXTENDING FROM
ERN COLORADO UP INTO THE ERN DAKOTAS. TEMPS AND DEWPS FALL OFF TO
WITHIN 10 DEGS OF EITHER SIDE OF ZERO WITHIN THE RIDGE AXIS...THOUGH
THIS RIDGE AXIS ALSO HAS WHAT HAS BEEN A RARITY THIS MONTH...MOSTLY
CLEAR SKIES. ITS LOOKING LIKE GOOD BET FOR SEEING SOME SUN TODAY
WEST OF I-35. EAST OF I-35...THE CLEARING WILL BE RACING
SUNSET...THOUGH BY THE TIME YOU GET TO EAU CLAIRE...IT`S A PRETTY
GOOD BET THAT SKIES WILL REMAIN OVERCAST THROUGH THE DURATION OF
DAYLIGHT HOURS. THESE MAINLY CLEAR SKIES MAY CAUSE TEMPERATURES TO
BE A BIT COOLER THAN WHAT IS CURRENTLY FORECAST TONIGHT...ESPECIALLY
WHERE WE ARE SEEING SNOW RIGHT NOW FROM SOUTHERN MN INTO WRN WI. OF
COURSE OUR TIME WITH CLEARISH SKIES WILL BE SHORT LIVED...AS BY 12Z
SUNDAY...THE ARCTIC BOUNDARY WILL BE SLIPPING INTO CENTRAL MN...WITH
CLOUD COVER INCREASING AHEAD OF THE FRONT AS IT DROPS SOUTH ACROSS
NRN MN THROUGH THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 329 AM CST SAT DEC 27 2014
THE MAIN HIGHLIGHT OF THE LONG TERM FORECAST PERIOD WILL BE THE
RETURN TO BELOW NORMAL TEMPERATURES BEFORE WE RING IN THE NEW
YEAR. OTHER THAN A SLIM CHANCE FOR SNOWFALL ON SUNDAY NIGHT INTO
MONDAY AS THE ARCTIC BOUNDARY RESPONSIBLE FOR THE AFOREMENTIONED
COOL DOWN IN TEMPERATURES MOVES THROUGH...DRY WEATHER IS EXPECTED
UNTIL POSSIBLY NEXT FRIDAY.
SUNDAY WILL LIKELY BE THE ONE AND ONLY MILD DAY THROUGH MOST OF
THE UPCOMING WEEK IN ADVANCE OF THE COLD FRONT. MODEL AGREEMENT WITH
THIS FEATURE HAS NOT REALLY SHOWN MUCH IMPROVEMENT OVER THE LAST
24 HOURS. THE ECMWF HAS BEEN FAIRLY INSISTENT THAT THE FORECAST
AREA WILL MISS OUT ON SNOWFALL WITH THIS FEATURE...WHILE THE
SREF...NAM...AND NOW 27.00 GFS THINK SOUTHERN MN WILL SEE A 1-3
INCH SNOWFALL ON SUNDAY NIGHT AND MONDAY MORNING. SINCE THE ECMWF
IS A BIT OF AN OUTLIER FROM THE OVERALL MODEL CONSENSUS SOLUTION...WHICH
HAS SHOWN UP FOR MULTIPLE RUNS...HAVE INCLUDED 30 POPS FOR 00Z-18Z
MONDAY GENERALLY SOUTH OF INTERSTATE 94. HAVE HOWEVER KEPT SNOWFALL
ACCUMULATIONS AROUND ONE INCH OR LESS WITH THE THOUGHT THE
FORCING/MOISTURE MIGHT BE WEAKER/LOWER THAN PROGGED BY THE
CONSENSUS.
WHILE CONFIDENCE IS RATHER LOW WITH RESPECT TO SNOWFALL CHANCES AS
THIS BOUNDARY SURGES ACROSS THE AREA...WHAT IS MORE CERTAIN IS
THAT A BLAST OF COLDER AIR WILL FOLLOW IN ITS WAKE. THERE IS STILL
FINE AGREEMENT THAT H85 TEMPERATURES WILL REDUCE TO -18C TO -20C
BY TUESDAY. SUB-ZERO LOWS FOR TUESDAY AND WEDNESDAY MORNINGS ARE
FAIRLY CERTAIN...ALONG WITH HIGHS IN THE SINGLE DIGITS TO LOW
TEENS. WIND CHILLS WILL SNEAK TO AROUND -20F TO -30F ON MONDAY
NIGHT AND TUESDAY NIGHT...BUT MODERATE A TAD /-10F/ FOR NEW YEARS
EVE AS LOW TEMPERATURES RECOVER TO ABOVE ZERO VALUES.
AT THE END OF THE UPCOMING WEEK...GFS AND ECMWF MODELS FORECAST ANOTHER
WAVE TO DROP SOUTH FROM CANADA...THIS TIME THROUGH THE BASE OF A
HUDSON/JAMES BAY CYCLONE. WHILE TIMING/AMPLITUDE DETAILS ARE A BIT
UP IN THE AIR AT THIS POINT...THE PROGS DO WARRANT INCLUSION OF
20-30 POPS FOR SNOW ON FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 542 AM CST SAT DEC 27 2014
ONLY REAL CHANGE MADE TO SNOW WITH 12Z TAFS WAS TO DELAY
IMPROVEMENTS BY ABOUT AN HOUR AS IFR VSBYS STILL EXTENDED BACK TO
THE WRN EDGE OF THE MN/IA BORDER. SNOW WILL RAPIDLY PULL OUT THIS
MORNING...AND DRIER AIR COMING IN FROM THE DAKOTAS WILL ALSO CLEAR
OUT THE STRATUS...FOLLOWED A RAP TIMING FOR THOSE IMPROVEMENTS.
OTHERWISE...WINDS WILL VEER OVER TO THE WSW THIS AFTERNOON AS A
COLD FRONT DROPS INTO NRN MN. THIS FRONT WILL MOVE INTO CENTRAL MN
AFTER 9Z AND MAY BRING A RENEWED THREAT OF MVFR CIGS...BUT NO SNOW
IS EXPECTED WITH THIS BOUNDARY. REALLY...ONLY PART OF FORECAST
THAT HAS LOWER CONFIDENCE IS TIMING OF CIG IMPROVEMENTS TO VFR.
KMSP...BASED ON THE RAP/HRRR...EXPECT IFR VIS SNOW TO END BETWEEN
14Z AND 15Z...WITH ALL SNOW DONE BY 17Z. KEPT THE CIG IMPROVEMENT
AT 20Z...THOUGH THE RAP/HRRR WOULD SAY THAT COULD TAKE TO AS LONG
AS 00Z TO GET HERE. ARCTIC FRONT WILL WORK ACROSS THE FIELD LATE
SUNDAY MORNING. THOUGH NO PRECIP IS EXPECTED...WE MAY SEE CIGS
COME BACK DOWN TO MVFR FOR A BIT IN ITS WAKE.
/OUTLOOK FOR KMSP/
SUN...VFR...CHC MVFR CIGS. WINDS BCMG NE 5-10 KTS.
MON...VFR. WINDS N 10 KTS.
TUE...VFR. WINDS NW 5-10 KTS
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ053-
060>063-065>070-073>078-082>085-091>093.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-
023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
328 AM CST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST SAT DEC 27 2014
AFTER TAKING MOST OF DECEMBER OFF...THE SHORT TERM PERIOD MARKS THE
BEGINNING OF THE RETURN OF WEATHER THAT IS MORE TYPICAL OF WHAT WE
WOULD EXPECT IN THE HEART OF WINTER...AT LEAST FOR TEMPERATURES.
FEATURE DRIVING SNOW ACROSS THE AREA THIS MORNING SHOWS UP WELL ON
SATELLITE WITH A NICE SWIRL MOVING INTO THE SIOUX FALLS AREA...WITH
A NICE DRY SLOT NOSING INTO SE MN. THIS DRY SLOT IS ASSOCIATED WITH
A TROWAL...WHICH HAS HELPED FORCE A NICE DEFORMATION BAND OF PRECIP
TO THE NW OF IT. MODELS GOING BACK TO THE 00Z RUNS LAST NIGHT HAVE
ACTUALLY DONE A GOOD JOB HANDLING THIS SNOW AND PRETTY MUCH FOLLOWED
THE HOPWRF AND HRRR FOR ENDING SNOW ACROSS THE AREA THIS MORNING.
EVERYTHING APPEARS ON TRACK FOR A HEALTHY SWATH OF 3 TO 5 INCHES.
BACK TO THE WEST OF THIS LOW...THERE IS A RIDGE AXIS EXTENDING FROM
ERN COLORADO UP INTO THE ERN DAKOTAS. TEMPS AND DEWPS FALL OFF TO
WITHIN 10 DEGS OF EITHER SIDE OF ZERO WITHIN THE RIDGE AXIS...THOUGH
THIS RIDGE AXIS ALSO HAS WHAT HAS BEEN A RARITY THIS MONTH...MOSTLY
CLEAR SKIES. ITS LOOKING LIKE GOOD BET FOR SEEING SOME SUN TODAY
WEST OF I-35. EAST OF I-35...THE CLEARING WILL BE RACING
SUNSET...THOUGH BY THE TIME YOU GET TO EAU CLAIRE...IT`S A PRETTY
GOOD BET THAT SKIES WILL REMAIN OVERCAST THROUGH THE DURATION OF
DAYLIGHT HOURS. THESE MAINLY CLEAR SKIES MAY CAUSE TEMPERATURES TO
BE A BIT COOLER THAN WHAT IS CURRENTLY FORECAST TONIGHT...ESPECIALLY
WHERE WE ARE SEEING SNOW RIGHT NOW FROM SOUTHERN MN INTO WRN WI. OF
COURSE OUR TIME WITH CLEARISH SKIES WILL BE SHORT LIVED...AS BY 12Z
SUNDAY...THE ARCTIC BOUNDARY WILL BE SLIPPING INTO CENTRAL MN...WITH
CLOUD COVER INCREASING AHEAD OF THE FRONT AS IT DROPS SOUTH ACROSS
NRN MN THROUGH THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 329 AM CST SAT DEC 27 2014
THE MAIN HIGHLIGHT OF THE LONG TERM FORECAST PERIOD WILL BE THE
RETURN TO BELOW NORMAL TEMPERATURES BEFORE WE RING IN THE NEW
YEAR. OTHER THAN A SLIM CHANCE FOR SNOWFALL ON SUNDAY NIGHT INTO
MONDAY AS THE ARCTIC BOUNDARY RESPONSIBLE FOR THE AFOREMENTIONED
COOL DOWN IN TEMPERATURES MOVES THROUGH...DRY WEATHER IS EXPECTED
UNTIL POSSIBLY NEXT FRIDAY.
SUNDAY WILL LIKELY BE THE ONE AND ONLY MILD DAY THROUGH MOST OF
THE UPCOMING WEEK IN ADVANCE OF THE COLD FRONT. MODEL AGREEMENT WITH
THIS FEATURE HAS NOT REALLY SHOWN MUCH IMPROVEMENT OVER THE LAST
24 HOURS. THE ECMWF HAS BEEN FAIRLY INSISTENT THAT THE FORECAST
AREA WILL MISS OUT ON SNOWFALL WITH THIS FEATURE...WHILE THE
SREF...NAM...AND NOW 27.00 GFS THINK SOUTHERN MN WILL SEE A 1-3
INCH SNOWFALL ON SUNDAY NIGHT AND MONDAY MORNING. SINCE THE ECMWF
IS A BIT OF AN OUTLIER FROM THE OVERALL MODEL CONSENSUS SOLUTION...WHICH
HAS SHOWN UP FOR MULTIPLE RUNS...HAVE INCLUDED 30 POPS FOR 00Z-18Z
MONDAY GENERALLY SOUTH OF INTERSTATE 94. HAVE HOWEVER KEPT SNOWFALL
ACCUMULATIONS AROUND ONE INCH OR LESS WITH THE THOUGHT THE
FORCING/MOISTURE MIGHT BE WEAKER/LOWER THAN PROGGED BY THE
CONSENSUS.
WHILE CONFIDENCE IS RATHER LOW WITH RESPECT TO SNOWFALL CHANCES AS
THIS BOUNDARY SURGES ACROSS THE AREA...WHAT IS MORE CERTAIN IS
THAT A BLAST OF COLDER AIR WILL FOLLOW IN ITS WAKE. THERE IS STILL
FINE AGREEMENT THAT H85 TEMPERATURES WILL REDUCE TO -18C TO -20C
BY TUESDAY. SUB-ZERO LOWS FOR TUESDAY AND WEDNESDAY MORNINGS ARE
FAIRLY CERTAIN...ALONG WITH HIGHS IN THE SINGLE DIGITS TO LOW
TEENS. WIND CHILLS WILL SNEAK TO AROUND -20F TO -30F ON MONDAY
NIGHT AND TUESDAY NIGHT...BUT MODERATE A TAD /-10F/ FOR NEW YEARS
EVE AS LOW TEMPERATURES RECOVER TO ABOVE ZERO VALUES.
AT THE END OF THE UPCOMING WEEK...GFS AND ECMWF MODELS FORECAST ANOTHER
WAVE TO DROP SOUTH FROM CANADA...THIS TIME THROUGH THE BASE OF A
HUDSON/JAMES BAY CYCLONE. WHILE TIMING/AMPLITUDE DETAILS ARE A BIT
UP IN THE AIR AT THIS POINT...THE PROGS DO WARRANT INCLUSION OF
20-30 POPS FOR SNOW ON FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1051 PM CST FRI DEC 26 2014
-SN HAS OVERSPREAD MUCH OF THE WFO MPX COVERAGE AREA...INCLUDING
CEILINGS FROM LOWER-END MVFR INTO BARELY IFR RANGE WITH VSBYS AS
LOW AS 1SM IN SOME OF THE HEAVIER SNOW BANDS. THE SNOWFALL WILL
CONTINUE TO FILL IN FROM THE SW OVERNIGHT...AFFECTING ALL BUT KAXN
AND POSSIBLY NOT KSTC...OR AT LEAST NOT AS BAD AT KSTC AS THE
REMAINING TAF SITES. ALL SITES /BUT KAXN/ WILL EXPERIENCE FLIGHT
CATEGORY REDUCTIONS AT TIMES TO IFR DURING THE FIRST HALF OF THIS
TAF PERIOD. HAVE DROPPED CONDS TO AS LOW AS 1SM...BUT GOING LESS
THAN THAT FOR VSBY CERTAINLY CANNOT BE RULED OUT. SAME WITH
CEILINGS...SEEING IFR CONDS WILL BE LIKELY WITH CEILINGS INTO LIFR
NOT UNREASONABLE. CONDS WILL IMPROVE FROM DAYBREAK ON THRU LATE
MRNG AS THE -SN PULLS OUT. VFR CONDS ARE EXPECTED BY LATE SAT
AFTN INTO EARLY SAT EVE.
KMSP...CONDS HAVE IMPROVED AT KMSP...EVEN TO VFR AT TIMES...AFTER
THE INITIAL BAND OF SNOW DEVELOPED OVER THE S/E TWIN CITIES
METRO AT THE START OF THE 27/00Z TAF. MORE WIDESPREAD SNOW IS
EXPECTED DURING THE THE EARLY MRNG HRS. CONDS IMPROVE AROUND
DAYBREAK. VSBY MAY WELL DROP BELOW 1SM FOR A TIME...BUT RATES OF 1
IN/HR ARE NOT EXPECTED BUT WILL CONTINUE TO MONITOR FOR ANY
POTENTIAL OF AN AIRPORT WEATHER WARNING AS THE EVENT UNFOLDS.
AFTER DAYBREAK...CEILINGS WILL INCRS TO MVFR LEVELS AND LIKELY GO
TO VFR SAT AFTN-EVE.
/OUTLOOK FOR KMSP/
SUN...VFR...CHC MVFR CIGS. WINDS S 5 KTS...BCMG E.
MON...VFR. WINDS N 10 KTS.
TUE...VFR. WINDS NW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ053-
060>063-065>070-073>078-082>085-091>093.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-
023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS JACKSON MS
316 PM CST SAT DEC 27 2014
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...WV IMAGERY THIS
AFTERNOON SHOWING MID/UPPER LEVEL SYSTEM CONTINUING TO DIG
SOUTH...NOW ENTERING NW MEXICO. TO THE EAST...MID/UPPER LEVEL
ANTICYCLONE REMAINS NEARLY STATIONARY OVER THE CARRIBEAN. RESULTING
FLOW IN BETWEEN HAS BECOME INCREASINGLY SSW ALLOWING THE MOISTURE
RICH AIR (PWATS NEAR 2 INCHES) OVER THE NW GULF OF MEXICO TO BE
TAPPED.
ALREADY...ELEVATED CONVECTIVE CLUSTERS MOVING OVER SE MS HAVE
PRODUCED SUBSTANTIAL RAINS WITH SPORADIC STREET FLOODING BEING
REPORTED. LATEST HRRR DATA IS INDICATING CONVECTION WILL FILL BACK
IN ALONG THE MID 60 DEWPOINT AXIS...CURRENTLY BISECTING LA...AS IT
MOVES INTO WESTERN MS EARLY THIS EVENING. BELIEVE THE AXIS OF
HEAVIEST RAINS WILL SET UP ALONG THE EASTERN FLANK OF THE DEWPOINT
GRADIENT WHICH WILL OCCUR COINCIDE WITH THE AXIS OF HIGHEST PWAT
COMING IN OFF THE NORTHERN GULF OF MEXICO. THE NAM...HRRR...GFS...
AND ECMWF ALL HAVE SIMILAR QPF SOLUTIONS.
WHILE PWAT VALUES AS HIGH AS WE ARE SEEING IS ANOMALOUS ENOUGH (+3
STANDARD DEVIATIONS)...EVEN MORE AMAZING IS THE FACT THAT THE
MAJORITY OF THE MOISTURE SEEMS TO BE LOCATED BELOW 700 MB WHEN
LOOKING AT AREA SOUNDINGS FROM THIS MORNING AND AFTERNOON. ABOVE 700
MB PROFILES ARE QUITE DRY. THIS HAS ALLOWED FOR CONVECTIVE
DESTABILIZATION AS MOISTURE CONTINUES TO STREAM IN AND IS MOST
LIKELY RESPONSIBLE FOR THE ELEVATED STORMS WITH HAIL THAT WE ARE
CURRENTLY SEEING. BELIEVE THIS WILL CONTINUE TO BE A PROBLEM TONIGHT
UNTIL THE COLUMN CAN BECOME SUBSTANTIALLY SATURATED. WILL CONTINUE
TO OUTLOOK OUR LIMITED SEVERE THREAT...BUT MOVE IT A LITTLE FURTHER
NORTH BASED ON CURRENT TRENDS. THERE STILL APPEARS TO BE A LIMITED
TORNADO THREAT OVER THE SOUTHERN FRINGES OF THE FORECAST AREA WHERE
MORE IN THE WAY OF SURFACE BASED CONVECTION CAN GET GOING.
FRONTAL BOUNDARY MOVING THROUGH AFTER MIDNIGHT WILL ALLOW RAINFALL
TO WANE SOMEWHAT. HOWEVER...DO EXPECT IT TO BREAK OUT AGAIN SUNDAY
AS WHATS LEFT OF PHASING MID LEVEL WAVE WORKS ITS WAY THROUGH.
RAINFALL WILL TAPER OFF RAPIDLY AFTER MIDNIGHT SUNDAY NIGHT./26/
.LONG TERM...MONDAY THROUGH SATURDAY...SURFACE HIGH PRESSURE RIDGING
WILL BUILD IN ON MONDAY ACROSS THE ARKLAMISS WITH COOLER HIGHS
RANGING FROM THE LOW TO MID 50S. LITTLE CHANGE IS EXPECTED TUESDAY...
BUT COLDER AIR WILL MOVE IN TUESDAY NIGHT AS COLD HIGH PRESSURE NOSES
INTO THE REGION. NEW YEARS EVE DAY TEMPERATURES WILL ONLY CLIMB INTO
THE 40S AND LOWER 50S. NEW YEARS EVE WILL BE COLD WITH LOWS WEDNESDAY
NIGHT FALLING INTO THE UPPER 20S/LOW 30S.
THE PATTERN OVER THE AREA WILL BEGIN TO CHANGE ON THURSDAY AS THE
SURFACE HIGH SHIFTS TO THE EAST AND AN UPPER TROUGH DEEPENS OVER THE
SOUTHERN PLANES. MOISTURE WILL INCREASE OVER THE AREA THURSDAY NIGHT
INTO FRIDAY WITH SHOWERS ON THE INCREASE FRIDAY AFTERNOON. THE
GLOBAL MODELS DIVERGE ON THEIR SOLUTIONS FRIDAY NIGHT INTO SATURDAY
WITH THE GFS TAKING THE SURFACE LOW NORTH AND THE ECMWF FURTHER
SOUTH. EITHER WAY SHOWERS AND STORMS WILL BE ON THE INCREASE AS WE
GET INTO THE WEEKEND WITH ANOTHER ROUND OF HEAVY RAINFALL AND
POSSIBLY SOME SEVERE STORMS./15/26/
&&
.AVIATION...LOW MVFR TO IFR CIGS NOW COVER AREA. TSRA WITH VERY
HEAVY RAIN MOVING THROUGH PINE BELT REGION HAS BEEN LOWERING VSBYS
TO LESS THAN 1SM AT TIMES AT KHBG THIS AFTERNOON. MORE OF THIS SORT
OF ACTIVITY WILL MOVE INTO KHBG AREA AFTER 22Z...AS WELL AS POTENTIALLY
IMPACT KGLH/KGWO/KHKS TOWARD 00Z. OVERALL...IFR CIGS WITH OCCASIONAL IFR
VSBYS/LIFR CIGS IN SHRA/TSRA WILL BE THE RULE TONIGHT AT ALL TAF
SITES. RAINFALL WILL TAPER OFF SOMEWHAT FROM WEST TO EAST 09Z TO 15Z
AS COLD FRONT SLOWLY MOVES EAST ACROSS REGION. WINDS WILL SHIFT TO THE
NW/N AFTER FROPA...AND BECOME GUSTY IN THE DELTA REGION AS STRONG HIGH
PRESSURE BUILDS INTO THE REGION. IFR/LOW MVFR CIGS WILL PERSIST IN THE
WAKE OF THE FRONT THROUGH AT LEAST 18Z. /AEG/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 52 54 42 53 / 100 97 94 8
MERIDIAN 58 62 45 56 / 100 94 95 14
VICKSBURG 48 50 40 52 / 100 98 89 6
HATTIESBURG 62 67 48 59 / 100 63 82 7
NATCHEZ 50 52 41 53 / 100 95 87 5
GREENVILLE 43 46 37 50 / 100 89 75 7
GREENWOOD 46 48 39 51 / 100 96 85 9
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR MSZ026>033-
036>039-042>066-072>074.
LA...FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR LAZ026.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1151 PM CST Fri Dec 26 2014
.UPDATE...
Issued at 958 PM CST FRI DEC 26 2014
Adjusted overnight PoPs for radar trends and added drizzle (did that
awhile back). Have also pulled Pops westward into the southwestern
CWA Saturday morning to account for latest HRRR trend towards
developing a secondary area of light precipitation northeastward into
east central KS/west central MO. Satellite imagery shows rapid
increase in upstream mid clouds from southeast NM through western OK.
Some question as to whether or not the 00z NAM`s dry wedge under this
cloud layer is real or not. 00z OKC sounding suggests otherwise. 12z
ECMWF supports the HRRR solution while the 00z GFS does pick up on
some QPF Sat morning making it into our southeastern CWA.
Precipitation type dependent on near surface temperatures and
vertical stratification of same. Tricky. Fortunately QPF should be
minor.
&&
.DISCUSSION...
Issued at 307 PM CST FRI DEC 26 2014
Cold front has reached the KC area this afternoon, though its
southward progress has slowed with a weak surface wave moving
up from the south. This feature is starting to produce some light
showers across west central Missouri, and light precip should
continue to blossom through the late afternoon and evening as low
pressure rides up the boundary. Precip amounts will be light,
generally less than a tenth of an inch, and mostly confined to areas
near and southeast of the I-35 corridor. Temperatures should remain
above freezing across these areas so no wintry precipitation is
expected.
Behind the front, a second area of precipitation developing over
central KS will spread into eastern Nebraska and northern Iowa
overnight where several inches of snow will accumulate, but most of
this snowfall now looks like it will miss our forecast area almost
entirely to the north. While far northwest Missouri may still see
some light snow later this evening, possibly even a bit of sleet, any
accumulations should be very minor and may not accumulate at all with
relatively warm ground temperatures.
Airmass behind the front will be seasonably chilly with highs in the
30s and lows in the teens/20s over the weekend. A stronger front will
swing through the region on Monday and looks to bring some of the
coldest air of the season so far. Highs Tuesday and Wednesday are
forecast to be in the 20s...maybe even teens for some areas...while
lows drop into the single digits. Wind chills could be between zero
and 10 below. Other than perhaps some very light snow accompanying
Monday`s front, the forecast through the middle of next week looks
dry. The pattern then looks to get active by late next week with both
GFS and ECMWF taking a closed upper low out of the Southwest and into
the Plains/Midwest by Friday/Saturday. Will be interesting to watch how
future model runs play out, but given the inherent low-predictability
with such a system, several swings in track and intensity are highly
likely and we are still days away from knowing any details, or even
if such a system will impact our region at all.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1140 PM CST FRI DEC 26 2014
Ceilings have finally begun to lower towards low MVFR and upper IFR
range as light rain across eastern KS moves northeastward towards
KSTJ and KMCI. KMKC looks to stay on the edge of the heavier band
with just a quick light shower in the near term. Question is if
disjointed band of rain showers currently across northeast OK will be
able to hold up and move up into eastern KS over the next several
hours. Lower ceilings and a reduction of VISIBILITIES are expected
to move in behind this current rain band given upstream obs. IFR deck
will begin to scatter out by mid morning with MVFR deck looking to
scatter out by 20-21Z. Skies will clear as the upper level system
moves east and surface high pressure moves into the region.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
DISCUSSION...Hawblitzel
AVIATION...PMM
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1127 PM CST FRI DEC 26 2014
.UPDATE...
ISSUED AT 1119 PM CST FRI DEC 26 2014
WILL BE UPDATING BY THE TOP OF THE HOUR FOR EXPIRATION OF MUCH OF
THE WINTER WEATHER ADVISORY. ONE MORE SIGNIFICANT BAND ALONG
HIGHWAY 30 NEAR GRAND ISLAND WILL EXIT NANCE AND MERRICK COUNTIES
AROUND 1230 AM. MUCH OF THE REST OF THE AREA WILL STILL HAVE SOME
RESTRICTED VISIBILITIES AND LIGHT SNOW FOR A FEW MORE HOURS...BUT
INTENSITY IS REALLY STARTING TO DROP OFF...WHICH WAS THE EXPECTED
TREND. WINDS ALSO REMAIN BELOW 15 MPH WHICH IS HELPFUL FOR LESS
BLOWING SNOW. TREND OF CLEARING ALREADY TAKING HOLD IN THE
SOUTHWEST PORTION OF THE FORECAST AREA...AND THAT WILL SPREAD
NORTHEAST THROUGH THE NIGHT.
UPDATE ISSUED AT 914 PM CST FRI DEC 26 2014
SENT AN UPDATE TO THE FORECAST TO REFINE THE TIMING OF PRECIP
THROUGH THE OVERNIGHT HOURS...LINGERING SOME LIGHT ACCUMULATING
SNOWFALL ACROSS OUR NORTHERN COUNTIES THROUGH THE EARLY MORNING
HOURS SATURDAY WHERE THE ADVISORY WAS RECENTLY EXTENDED. LATEST
SATELLITE IMAGERY SHOWS THE UPPER LEVEL LOW ACROSS WESTERN
NEBRASKA BEGINNING TO PIVOT AND LIFT NORTHEASTWARD...WHICH SHOULD
RESULT IN SNOWFALL TAPERING OFF FROM SOUTH TO NORTH OVERNIGHT.
FOLLOWED 02Z RAP GUIDANCE FAIRLY CLOSELY WITH TIMING OF PRECIP AND
TEMPERATURES OVERNIGHT...WITH NO CHANGES MADE TO THE PREVIOUS
FORECAST BEYOND THE OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 324 PM CST FRI DEC 26 2014
WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT TONIGHT.
AT 21Z...SNOWFALL WAS ONGOING ACROSS PARTS OF OUR WESTERN AND
SOUTHWESTERN COUNTIES. SNOWFALL WILL CONTINUE TO OVERSPREAD AREAS
EAST THROUGHOUT THE REST OF THE AFTERNOON AND INTO THE EVENING
HOURS. ACROSS THE ADVISORY AREA...2 TO 4 INCHES IS EXPECTED...AND
GENERALLY 1 TO 3 ACROSS THE REST OF THE OUTLOOK AREA. FOR THE HEART
OF THE CWA...WHICH IS BASICALLY THE TRI-CITIES...WE ARE CONFIDENT
THE HEAVIEST SNOWFALL WILL LIKELY FALL BETWEEN 6PM AND 9 PM TONIGHT.
SNOWFALL WILL CONTINUE UNTIL ABOUT 11PM/MIDNIGHT BEFORE TAPERING
OFF. FOR 00Z...FORECAST SOUNDINGS FOR GRAND ISLAND SHOWED THE
STRONGEST OMEGA VALUES WHICH COINCIDED WITH A MOIST DGZ
LAYER...HENCE THE CONFIDENCE FOR HEAVIEST SNOWFALL DURING THIS TIME.
ALSO HELPING CREATE A FAVORABLE TIME FRAME FOR HEAVIEST SNOW AROUND
00Z IS AN AREA OF ISENTROPIC LIFT CENTERED THROUGH MOST OF THE
CWA...ALBEIT THIS TIME FRAME IS LIMITED TO ABOUT 3 HOURS.
THEREAFTER...WE QUICKLY BEGIN TO LOSE FORCING AND MOISTURE...SO
CONFIDENT SNOW WILL RETREAT FROM THE SOUTHWEST TO NORTHEAST BETWEEN
MIDNIGHT AND SUNRISE SATURDAY MORNING.
CLOUD COVER WILL SLOWLY DECREASE LATE SATURDAY MORNING/EARLY
AFTERNOON...AND WE SHOULD SEE SOME SUNNY SKIES MID TO LATE SATURDAY
AFTERNOON. HIGHS WILL BE ON THE COOL SIDE...WITH MID/UPPER 20S TO
LOWER 30S CURRENTLY FORECAST. LOWS TONIGHT WILL GENERALLY RANGE
BETWEEN THE TEENS AND LOWER 20S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 324 PM CST FRI DEC 26 2014
SUGGEST HAVING THE HEAVY WINTER COATS/GLOVES/HATS READY AND THOSE
WHO USE WOOD STOVES FOR HEAT KEEP PLENTY OF WOOD CLOSE BY. WE ARE IN
FOR ANOTHER PERIOD OF SERIOUS WINTER COLD...BUT THIS TIME MUCH
COLDER THAN NOV!
THE COLDEST HIGH TEMP IN GRAND ISLAND /GRI/ WAS 20F ON THE NOV 17TH.
WE WILL EXPERIENCE THE COLDEST AIR SO FAR THIS COLD SEASON. WE HAVE
TWO DAYS IN THIS FCST IN WHICH HIGHS WILL BE COLDER THAN 20F.
NOT QUITE CONFIDENT YET TO STATE HOW MANY CONSECUTIVE DAYS TEMPS
COULD REMAIN AT OR BELOW FRZG. DOWNSLOPE WARMING IS ALWAYS A
WILDCARD BETWEEN ARCTIC FRONTAL PASSAGES AS THE HIGHS DROP S OF THE
REGION. SUFFICE TO SAY THERE COULD BE A 1 OR 2 DAY INTERRUPTION...
BUT OVERALL BELIEVE WE ARE LOOKING AT AN EXTENDED STRETCH OF COLD
WX BEGINNING MON.
MODELS: THE EC/GFS/UKMET/GEM AND THE ENSEMBLE MEANS CONT IN VERY
GOOD AGREEMENT ON THE OVERALL PATTERN THRU FRI 1/2 AND ALL THE
WAY OUT THRU 10 DAYS.
THE LONGWAVE FLOW WILL BE HIGHLY AMPLIFIED WITH A RIDGE OVER THE NE
PAC INTO AK WITH A DOWNSTREAM +TILT TROF FROM HUDSON BAY INTO THE
WRN USA. THIS IS THE PATTERN WE SAW IN NOV AND IT WILL DELIVER BELOW
NORMAL TEMPS NEXT WEEK...WITH A COUPLE TWO-DAY PERIODS OF MUCH BELOW
NORMAL BITTER COLD. THAT MEANS DAYTIME HIGHS IN THE SINGLE DIGITS AND
TEENS WHICH WILL BE 20-25F COLDER THAN NORMAL. AS OF NOW THE COLDEST
DAYS ARE SLATED FOR 12/30-31 WITH HIGH CONFIDENCE AND 1/3-4 WITH
LOW CONFIDENCE.
ALOFT: A BROAD TROF WITH GENERALLY W FLOW WILL BE OVER THE PLAINS
THRU TUE. A SHORTWAVE TROF IS CURRENTLY CRESTING THE RIDGE OVER THE
GULF OF AK. THIS TROF WILL DIVE INTO THE WRN USA SAT-MON AND CUT-OFF
OVER CA TUE...GRADUALLY SINKING INTO THE DESERT SW THRU FRI.
CONFLUENT NW FLOW WILL DEVELOP OVER THE CNTRL USA IN THE MEANTIME.
ANOTHER SHORTWAVE TROF DIVING THRU WRN N AMERICA LATE NEXT WEEK
SHOULD KICK THIS LOW E...RESULTING IN A SIZABLE STORM FOR THE CNTRL/
ERN USA AND ANOTHER COLD SURGE. LOOKS LIKE THE NEXT WX-MAKER WILL BE
A WEAK SHORTWAVE TROF SUN NIGHT INTO MON.
SURFACE: HIGH PRES WILL BE OVERHEAD SAT EVE AND DRIFT S AND E OF THE
REGION OVERNIGHT WHILE THE LEADING EDGE OF THE ARCTIC AIR SPILLS
INTO THE NRN USA. THE FRONT WILL MOVE THRU SUN NIGHT WITH BITTERLY
COLD ARCTIC HIGH PRES OVER WRN CANADA SLOWLY SLIDING DOWN THE FRONT
RANGE. THIS HIGH WILL BE OF THE 1050+ MB VARIETY AND WILL BE
OVERHEAD DAYBREAK WED. IT THEN HEADS INTO THE SRN USA THU-FRI. AN
ALBERTA CLIPPER WILL DIVE SE INTO THE NRN PLAINS HERALDING THE NEXT
SURGE OF ARCTIC AIR WITH ITS ARRIVAL PROBABLY NEXT WEEKEND. SRN
PLAINS CYCLOGENESIS APPEARS IN THE OFFING LATE NEXT WEEK. THIS WILL
BEEN TO BE WATCHED.
THE DAILY DETAILS...
PLEASE GIVE US SOME LATITUDE ON TEMPS. FRESH SNOWCOVER IS ALWAYS A
SIGNIFICANT COMPLICATION ON TEMP FORECASTING.
SUN: A SUNNY START...BUT INCREASING MULTI-LAYERED MID-HIGH CLOUDS.
SUN NIGHT: ARCTIC COLD FRONTAL PASSAGE.
MON: CLOUDY/BLUSTERY AND COLD. STEADY OR SLOWLY FALLING TEMPS IN
COLD AIR ADVECTION. FOR MOST LOCATIONS DAYTIME HIGHS WILL OCCUR AT
DAWN. N WINDS WILL GUST TO 30 MPH AT TIMES. COULD SEE A BURST OF
LIGHT SNOW WITH THE WEAK SHORTWAVE TROF AND DEEP MOISTURE.
CANT RULE OUT A WIND-BLOWN INCH OR SO BUT IT/S WAY TOO EARLY AND THE
POTENCY ALOFT IS LACKING. FOR WHAT IT/S WORTH THE 06Z/12Z GFS
INDICATE THIS POTENTIAL...BUT THE SREF PROBABILITIES FOR .10" QPF
ARE CURRENTLY HIGHEST ALONG THE NEB-SD BORDER.
TUE: BITTERLY COLD. HIGHS ONLY IN THE SINGLE DIGITS FOR MUCH OF S-
CNTRL NEB. MID TEENS FOR N-CNTRL KS. WATCH YOUR HOME BAROMETERS. IF
IT/S ARE CALIBRATED...YOU WILL LIKELY SEE PRESSURE EXCEEDING 30.80".
WED: COULD BE A VERY VERY COLD START AS LONG AS CLOUDS ARE NOT A
FACTOR. COLDEST LOCATIONS WOULD BE THE USUAL COLD SPOTS N AND W OF
THE TRI-CITIES...ESPECIALLY THE LOUP RVR VALLEY. HIGH PRES OVERHEAD
TUE NIGHT WOULD RESULT IN VERY LIGHT WINDS.
THU-FRI: MODERATING TEMPS. DRY THU AND PROBABLY FRI. BUT FRI NEEDS
TO BE WATCHED AS LOW PRES WILL BE ORGANIZING S OF THE REGION. GFS
ENSEMBLES SUGGEST THIS LOW WILL MISS WELL SE OF THE FCST AREA... BUT
A LOT CAN CHANGE BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI DEC 26 2014
MVFR CONDITIONS WILL LINGER FOR A COUPLE MORE HOURS AS THE SNOW
BAND STARTS TO MOVE NORTHEAST OF THE AREA. SEEING TRENDS TOWARD
CLEARING ALREADY MOVING INTO THE SOUTH CENTRAL NEBRASKA...SO
FAIRLY QUICK IMPROVEMENT TO VFR CONDITIONS WILL BE FOUND BY DAWN.
WINDS WILL GRADUALLY DROP THROUGH THE DAY TO LESS THAN 10KTS. VFR
CONDITIONS ARE EXPECTED AFTER DAWN AND INTO TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ041-
046>048-060>062-072>074-082-083.
WINTER WEATHER ADVISORY UNTIL 4 AM CST SATURDAY FOR NEZ039-040.
KS...NONE.
&&
$$
UPDATE...NOAA/NWS/MORITZ
SHORT TERM...GUERRERO
LONG TERM...HALBLAUB
AVIATION...NOAA/NWS/MORITZ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
933 PM EST SUN DEC 28 2014
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE
SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT
LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH MONDAY/...
930 PM UPDATE...
LAKE ENHANCED SNOW SHOWERS NOW ENTERING FAR NORTHERN ONEIDA COUNTY
AS HAD BEEN ANTICIPATED /IF ANYTHING...JUST A SMIDGE AHEAD OF
SCHEDULE/. THROUGH MIDNIGHT...ONLY A FEW TENTHS OF AN INCH SNOW
ACCUMULATION EXPECTED THERE MAINLY IN THE HIGHER TERRAIN NORTH OF
THE THRUWAY. FORECAST REMAINS ON TRACK.
625 PM UPDATE...
SMALL CLUSTER OF LIGHT SNOW SHOWERS HAS CARRIED ACROSS THE ONTARIO
PENINSULA...AND NOW OVER WESTERN TO CENTRAL LAKE ONTARIO WHILE
BECOMING LAKE ENHANCED. THIS ACTIVITY EN ROUTE TO ONEIDA COUNTY
MAINLY NORTH OF THE THRUWAY 03Z-06Z TO PERHAPS YIELD A VERY LIGHT
SKIFF OF SNOW. THEN MINOR LAKE EFFECT TO CONTINUE OVERNIGHT INTO
MONDAY MORNING VIA 270 FLOW GRADUALLY VEERING 290-300...WITH
ACCUMULATIONS VERY LIGHT IF ANY /AGAIN ON ORDER OF TENTHS OF AN
INCH/. FORECAST TWEAKED FOR SMALLER DETAILS...OVERALL IN FINE
SHAPE.
PREVIOUS DISCUSSION...
SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW
FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY
DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE
TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS
XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE
AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV
NRML FOR THE SEASON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL
INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON
AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK
SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY
LYR FLOW WITHOUT ENHANCING THE LE.
LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A
BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE
THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY
TO BE OVER THE NRN THIRD OF THE FCST AREA.
BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE
SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER
ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG
MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND
THAT DVLPS NORTH OF THE FCST AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL
AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT
SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY.
A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL
SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION
MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER,
ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY,
TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL
CHANGE TO RAIN.
GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT
AREAS.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
A MIX OF MVFR AND VFR CIGS CAN BE EXPECTED THROUGH TONIGHT. CIGS
WILL RISE A BIT MORE ON MONDAY WITH MOSTLY VFR BY AFTERNOON. WINDS
WILL BE FROM THE NW AT 5 TO 10 KTS THROUGH MONDAY.
OUTLOOK...
MON...VFR.
TUE/WED/THU...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR
KRME/KSYR...DUE TO LAKE EFFECT -SHSN. OTRWS...VFR IS EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...DJP
AVIATION...DJP/MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
632 PM EST SUN DEC 28 2014
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE
SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT
LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH MONDAY/...
625 PM UPDATE...
SMALL CLUSTER OF LIGHT SNOW SHOWERS HAS CARRIED ACROSS THE ONTARIO
PENINSULA...AND NOW OVER WESTERN TO CENTRAL LAKE ONTARIO WHILE
BECOMING LAKE ENHANCED. THIS ACTIVITY EN ROUTE TO ONEIDA COUNTY
MAINLY NORTH OF THE THRUWAY 03Z-06Z TO PERHAPS YIELD A VERY LIGHT
SKIFF OF SNOW /TENTH INCH OR SO/. THEN MINOR LAKE EFFECT TO
CONTINUE OVERNIGHT INTO MONDAY MORNING VIA 270 FLOW GRADUALLY
VEERING 290-300...WITH ACCUMULATIONS VERY LIGHT IF ANY /AGAIN ON
ORDER OF TENTHS OF AN INCH/. FORECAST TWEAKED FOR SMALLER
DETAILS...OVERALL IN FINE SHAPE.
PREVIOUS DISCUSSION...
SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW
FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY
DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE
TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS
XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE
AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV
NRML FOR THE SEASON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL
INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON
AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK
SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY
LYR FLOW WITHOUT ENHANCING THE LE.
LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A
BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE
THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY
TO BE OVER THE NRN THIRD OF THE FCST AREA.
BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE
SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER
ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG
MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND
THAT DVLPS NORTH OF THE FCST AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL
AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT
SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY.
A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL
SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION
MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER,
ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY,
TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL
CHANGE TO RAIN.
GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT
AREAS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A MIX OF MVFR AND VFR CIGS CAN BE EXPECTED THROUGH TONIGHT. CIGS
WILL RISE A BIT MORE ON MONDAY WITH MOSTLY VFR BY AFTERNOON. WINDS
WILL BE FROM THE NW AT 5 TO 10 KTS THROUGH MONDAY.
OUTLOOK...
MON...VFR.
TUE/WED/THU...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR
KRME/KSYR...DUE TO LAKE EFFECT -SHSN. OTRWS...VFR IS EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...DJP
AVIATION...DJP/MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
625 PM EST SUN DEC 28 2014
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE
SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT
LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH MONDAY/...
625 PM UPDATE...
SMALL CLUSTER OF LIGHT SNOW SHOWERS HAS CARRIED ACROSS THE ONTARIO
PENINSULA...AND NOW OVER WESTERN TO CENTRAL LAKE ONTARIO WHILE
BECOMING LAKE ENHANCED. THIS ACTIVITY EN ROUTE TO ONEIDA COUNTY
MAINLY NORTH OF THE THRUWAY 03Z-06Z TO PERHAPS YIELD A VERY LIGHT
SKIFF OF SNOW /TENTH INCH OR SO/. THEN MINOR LAKE EFFECT TO
CONTINUE OVERNIGHT INTO MONDAY MORNING VIA 270 FLOW GRADUALLY
VEERING 290-300...WITH ACCUMULATIONS VERY LIGHT IF ANY /AGAIN ON
ORDER OF TENTHS OF AN INCH/. FORECAST TWEAKED FOR SMALLER
DETAILS...OVERALL IN FINE SHAPE.
PREVIOUS DISCUSSION...
SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW
FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY
DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE
TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS
XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE
AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV
NRML FOR THE SEASON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL
INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON
AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK
SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY
LYR FLOW WITHOUT ENHANCING THE LE.
LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A
BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE
THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY
TO BE OVER THE NRN THIRD OF THE FCST AREA.
BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE
SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER
ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG
MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND
THAT DVLPS NORTH OF THE FCST AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL
AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT
SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY.
A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL
SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION
MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER,
ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY,
TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL
CHANGE TO RAIN.
GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT
AREAS.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
WIDESPREAD MVFR CEILINGS WILL RISE SLIGHTLY THIS EVENING. CEILINGS
OVERNIGHT ARE FORECAST TO RANGE FROM 2500 TO 4000 FEET, WITH
NORTH-NORTHWEST WINDS AROUND 7 TO 10 KNOTS.
SOME CLEARING IS POSSIBLE LATER MONDAY MORNING. THERE EXIST MODEL
DIFFERENCES WITH RESPECT TO AMOUNT OF LOW LEVEL MOISTURE. GFS
TRIES TO CLEAR SKIES OUT, WHEREAS NAM KEEPS MOISTURE LOCKED IN.
LEANING TOWARD GFS AT THE MOMENT.
OUTLOOK...
MON...VFR.
TUE/WED/THU...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR
KRME/KSYR...DUE TO LAKE EFFECT -SHSN. OTRWS...VFR IS EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...DJP
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
329 AM EST SAT DEC 27 2014
.SYNOPSIS...HIGH PRESSURE OVERHEAD THIS MORNING WILL SHIFT EAST OF
THE AREA BY TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
ON SUNDAY... AND GRADUALLY MOVE SOUTHWARD THROUGH THE REGION ON
MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 840 PM FRIDAY...
ANOTHER QUIET NIGHT WITH BOTH SURFACE HIGH PRESSURE AND MID LEVEL
RIDGING OVERHEAD AND DEEP DRY AND STABLE AIR FROM THE SURFACE UP
THROUGH 500 MB. A SLUG OF HIGHER LEVEL MOISTURE TRACKING AROUND THE
PERIPHERY OF THE RIDGE... NOW MOVING OVER TN/KY/WV/VA... WILL AFFECT
FAR NRN AND NW CWA WITH A PERIOD HIGH THIN CLOUDS... HOWEVER THIS IS
UNLIKELY TO HAVE MUCH IF ANY IMPACT ON TEMPS. WINDS HAVE GONE CALM
IN MOST AREAS... FACILITATING A GOOD TEMP DROP THIS EVENING.
DEWPOINT DEPRESSIONS ARE ALREADY DOWN TO JUST A FEW DEGREES
ESPECIALLY IN THE EAST... WHERE DEWPOINTS ARE GENERALLY HIGHER THAN
IN THE WEST... AND THE LATEST HRRR DEPICTS AREAS OF FOG FORMING
AFTER 09Z ALONG THE I-95 CORRIDOR. HAVE ADDED A MENTION OF FOG IN
THE COASTAL PLAIN LATE TONIGHT INTO SAT MORNING. OTHERWISE... EXPECT
MOSTLY CLEAR SKIES. LOWS 29-36... LOWEST IN OUTLYING AREAS. -GIH
THE HIGH WILL BEGIN TO SLIP OFFSHORE ON SATURDAY AHEAD OF OUR NEXT
SYSTEM. THE AIRMASS WILL UNDERGO FURTHER MODIFICATION AS RETURN FLOW
SETS UP OVER THE REGION. HIGHS SHOULD RISE INTO THE UPPER 50S TO
NEAR 60 DEGREES ACROSS THE NORTHWEST (WHERE MID/HIGH CLOUDS WILL BE
FIRST TO ARRIVE) AND INTO THE LOW/MID 60S FURTHER SOUTHEAST. -KRD
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 305 PM FRIDAY...
SATURDAY NIGHT...SW FLOW ALOFT WILL USHER IN A SERIES OF
DISTURBANCES FROM THE NORTHERN GULF INTO THE SOUTHERN
APPALACHIANS/MID-ATLANTIC REGION. LEAD DISTURBANCE PROJECTED TO
ADVANCE TOWARD OUR REGION LATE SATURDAY NIGHT. MID LEVEL FLOW WILL
GRADUALLY VEER IN RESPONSE TO THIS FEATURE...AIDING IN MOISTURE
TRANSPORT INTO THE REGION. SFC RIDGE IS EXPECTED TO REMAIN ALIGNED
WSW-ENE ACROSS CENTRAL NC...MAINTAINING A DRY AIR PRESENCE. LOW
LEVEL ISENTROPIC LIFT ANEMIC DURING THIS PERIOD SO APPEARS LIFT
GENERATED ALOFT FROM WAA. EXPECT DRY CONDITIONS THROUGH SATURDAY
EVENING WITH PATCHES OF LIGHT RAIN SHOWING UP ON THE RADAR AFTER
MIDNIGHT IN THE WEST. INITIAL PATCHES OF RAIN WILL GO TO MOISTEN THE
SUB CLOUD LAYER. THUS...BEST SHOT OF MEASURABLE RAIN WILL LIKELY BE
CONFINED TO THE FAR WESTERN-SOUTHERN PIEDMONT.
SUNDAY...ATMOSPHERE EXPECTED TO REMAIN ADEQUATELY MOIST TO MAINTAIN
CONSIDERABLE CLOUDINESS. LEAD PERTURBATION EXPECTED TO CROSS JUST
WEST-NW OF OUR REGION IN THE MORNING. BULK OF PRECIP WITH THIS
FEATURE SHOULD OCCUR IN VICINITY OF THE PIEDMONT COUNTIES WITH RAIN
COVERAGE DECREASING TO THE SE. WILL TREND POPS FROM LIKELY NW THIRD
TO CHANCE FAR SE. BY AFTERNOON...EXPECT NOTHING MORE THAN SPOTTY
PRECIP AT THIS TIME WITH CHANCE POPS AREAWIDE. MAX TEMPS SUNDAY
DEPENDENT ON AREAL EXTENT OF RAIN OR SHOWERS. FAVOR BLEND OF MOS
GUIDANCE (UPPER 50S NW TO LOW-MID 60S SE). MORE EXTENSIVE/LONGER
DURATION RAIN WILL RESULT IN COOLER TEMPS BY 3-4 DEGREES.
SUNDAY NIGHT...MODEL GUIDANCE HAS GAINED SOME CONSENSUS ON A
SLIGHTLY MORE PRONOUNCED PERTURBATION AND ATTENDANT SURFACE WAVE TO
AFFECT OUR REGION SUNDAY NIGHT...ESPECIALLY AFTER MIDNIGHT. MAIN
LIFTING MECHANISM APPEARS TO BE FROM A 140+ UPPER JET LIFTING NWD
ACROSS THE NORTHERN MID ATLANTIC...PLACING CENTRAL NC IN THE
FAVORABLE RIGHT ENTRANCE REGION. THIS MAY LEAD TO RAINFALL AMOUNTS
ON THE ORDER OF A HALF INCH OVER THE PIEDMONT. PLAN TO TREND POPS
FROM CHANCE IN THE EVENING TO HIGH LIKELY LATE SUNDAY NIGHT INTO THE
FIRST PART OF MONDAY MORNING. LOWS IN THE MID 40S NW TO LOWER 50S SE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 325 AM SATURDAY...
MON AND MON NIGHT: THE MODELS ARE IN GOOD AGREEMENT ALOFT REGARDING
THE AMPLIFICATION OF A SHORTWAVE TROUGH ACROSS NORTHERN MEXICO
THROUGH TONIGHT... FOLLOWED BY A DEAMPLIFICATION OF THE TROUGH TO
THE MIDDLE ATLANTIC STATES BY EARLY MON. THE INTENSIFICATION AND
MIGRATION OF AN ASSOCIATED 160-180 KT UPPER JET ACROSS THE OH VALLEY
AND NORTHEAST WILL PLACE CENTRAL NC BENEATH THE RIGHT ENTRANCE
REGION OF THE JET...WHICH WILL CAUSE THE LOW LEVEL FLOW /ABOVE THE
SHALLOW POST-FRONTAL DAMMING HIGH/ TO ACCELERATE AND ASSUME A MORE
SOUTHERLY COMPONENT. STRENGTHENING ISENTROPIC LIFT WILL
RESULT...WHICH WILL CAUSE LIGHT RAIN TO OVERSPREAD CENTRAL NC LATE
SUNDAY NIGHT THROUGH EARLY MON AFTERNOON...BEFORE TAPERING TO
OCCASIONAL DRIZZLE OR BARELY MEASURABLE LIGHT RAIN...AS AN
ASSOCIATED SERIES OF WEAK FRONTAL WAVES TRACK OFF THE COAST OF THE
CAROLINAS...THROUGH MON NIGHT.
THE COMBINATION OF BOTH CAA AND DIABATIC/EVAPORATIVE COOLING WILL
LIKELY RESULT IN SLOWLY FALLING TEMPERATURES ACROSS THE NORTHERN
CWFA --INTO THE 40S-- THROUGHOUT THE DAY...WHILE THE SOUTHERN TIER
WILL HAVE AN OPPORTUNITY TO WARM INTO THE 60S DURING THE MIDDAY
HOURS BEFORE ALSO COOLING DURING THE AFTERNOON HOURS. LOWS...WITH
CONTINUED LOW OVERCAST AND THE AFOREMENTIONED OCCASIONAL DRIZZLE OR
VERY LIGHT RAIN...IN THE UPPER 30S TO LOWER 40S.
TUE: A SECONDARY SHORTWAVE TROUGH...ANOTHER DEAMPLIFYING ONE IN WSW
FLOW ALOFT...IS FORECAST TO CROSS THE CENTRAL APPALACHIANS EARLY
TUE. THE PASSAGE OF THIS FEATURE AND ASSOCIATED WEAK HEIGHT FALLS
ALOFT AND LIFT WILL MAINTAIN A SUFFICIENTLY SATURATED LOWEST SEVERAL
THOUSAND FT TO WARRANT A CONTINUED SLIGHT CHANCE OF LIGHT RAIN OR
(MORE LIKELY) DRIZZLE INTO EARLY TUE...BEFORE NW 925-850 MB FLOW
BEHIND THE PASSING SHORTWAVE PROMOTES BOTH DOWNSLOPE FLOW AND A
DISSIPATION OF THE CAD INVERSION VIA CAA - BOTH MECHANISMS THAT
SHOULD SERVE TO SCOUR THE CAD REGIME AND PROMOTE STEADY CLEARING.
WITH A FEW HOURS OF AFTERNOON SUNSHINE PROBABLE...LONGEST OVER THE
NW PIEDMONT...TEMPERATURES SHOULD RESPOND TO NEAR NORMAL.
TUE NIGHT-FRI: STRONG...ARCTIC HIGH PRESSURE OVER THE ROCKIES EARLY
IN THE PERIOD WILL OTHERWISE SPRAWL EAST ACROSS THE MIDDLE ATLANTIC
AND SOUTHEAST STATES...THROUGH THU...BENEATH GENERALLY WESTERLY FLOW
BETWEEN CONFLUENT BRANCHES OF THE UPPER JET...BEFORE DRIFTING
OFFSHORE AHEAD OF AN EJECTING DESERT SW (BRIEFLY) CUTOFF LOW FRI-
SAT. THE RESULT WILL BE COOL CONDITIONS --MOST NOTABLY WED AND THU
MORNINGS WHEN TEMPERATURES SHOULD DIP WELL INTO THE 20S GIVEN
PROJECTED LOW LEVEL THICKNESS VALUES IN THE 1290-1300 METER RANGE--
WITH A PERIOD OF PASSING MID-HIGH CLOUDS DURING THE DAY
WED...BETWEEN OTHERWISE MOSTLY CLEAR.
MEDIUM RANGE GUIDANCE (NOT SURPRISINGLY) DIVERGES WITH RESPECT TO
THE EJECTION OF THE AFOREMENTIONED DESERT SW LOW...SO FORECAST
DETAILS ARE MORE UNCERTAIN FOR FRI...THOUGH CLOUDINESS AND RAIN
CHANCES WILL CERTAINLY BE ON THE RISE THROUGH THE START OF NEXT
WEEKEND.
&&
.AVIATION /06Z SATURDAY THROUGH TUESDAY/...
AS OF 100 AM SATURDAY...
WITH DEWPOINTS SLIGHTLY HIGHER OVER THE COASTAL PLAIN AND LIGHT
WINDS...THERE MAY BE A COUPLE HOURS OF MVFR VSBY AT KRWI AND/OR KFAY
PRIOR TO 12Z...ESPECIALLY AS SKIES PARTIALLY CLEAR BETWEEN SOME HIGH
CLOUDS MOVING OVERHEAD. OTHERWISE.. VFR CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH THE TAF PERIOD WITH LIGHT WINDS BECOMING SOUTH-
SOUTHWESTERLY DURING THE DAY.
MID-LEVEL CLOUDS WILL INCREASE LATER TONIGHT AND EARLY SUNDAY AHEAD
OF A DISTURBANCE MOVING ALONG THE APPALACHIANS. HOWEVER...CURRENT
MODEL PROJECTIONS HAVE LOW CLOUDS AND SUB-VFR CEILINGS SPREADING
INTO THE KGSO/KINT VICINITY WELL AFTER 06Z SUNDAY.
LOOKING AHEAD: A SERIES OF UPPER-LEVEL DISTURBANCES MOVING SOUTHWEST
TO NORTHEAST ACROSS THE REGION COMBINED WITH AN APPROACHING FRONTAL
ZONE WILL BRING A COUPLE ROUNDS OF LIGHT PRECIP AND SUB-VFR
CONDITIONS TO PORTIONS OF CENTRAL NC SUNDAY AND MONDAY. CONDITIONS
ARE EXPECTED TO IMPROVE BY LATE MONDAY NIGHT INTO TUESDAY. -KRD
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...HARTFIELD/KRD
SHORT TERM...WSS
LONG TERM...MWS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 AM EST SAT DEC 27 2014
.SYNOPSIS...HIGH PRESSURE OVERHEAD THIS MORNING WILL SHIFT EAST OF
THE AREA BY TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
ON SUNDAY... AND GRADUALLY MOVE SOUTHWARD THROUGH THE REGION ON
MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 840 PM FRIDAY...
ANOTHER QUIET NIGHT WITH BOTH SURFACE HIGH PRESSURE AND MID LEVEL
RIDGING OVERHEAD AND DEEP DRY AND STABLE AIR FROM THE SURFACE UP
THROUGH 500 MB. A SLUG OF HIGHER LEVEL MOISTURE TRACKING AROUND THE
PERIPHERY OF THE RIDGE... NOW MOVING OVER TN/KY/WV/VA... WILL AFFECT
FAR NRN AND NW CWA WITH A PERIOD HIGH THIN CLOUDS... HOWEVER THIS IS
UNLIKELY TO HAVE MUCH IF ANY IMPACT ON TEMPS. WINDS HAVE GONE CALM
IN MOST AREAS... FACILITATING A GOOD TEMP DROP THIS EVENING.
DEWPOINT DEPRESSIONS ARE ALREADY DOWN TO JUST A FEW DEGREES
ESPECIALLY IN THE EAST... WHERE DEWPOINTS ARE GENERALLY HIGHER THAN
IN THE WEST... AND THE LATEST HRRR DEPICTS AREAS OF FOG FORMING
AFTER 09Z ALONG THE I-95 CORRIDOR. HAVE ADDED A MENTION OF FOG IN
THE COASTAL PLAIN LATE TONIGHT INTO SAT MORNING. OTHERWISE... EXPECT
MOSTLY CLEAR SKIES. LOWS 29-36... LOWEST IN OUTLYING AREAS. -GIH
THE HIGH WILL BEGIN TO SLIP OFFSHORE ON SATURDAY AHEAD OF OUR NEXT
SYSTEM. THE AIRMASS WILL UNDERGO FURTHER MODIFICATION AS RETURN FLOW
SETS UP OVER THE REGION. HIGHS SHOULD RISE INTO THE UPPER 50S TO
NEAR 60 DEGREES ACROSS THE NORTHWEST (WHERE MID/HIGH CLOUDS WILL BE
FIRST TO ARRIVE) AND INTO THE LOW/MID 60S FURTHER SOUTHEAST. -KRD
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 305 PM FRIDAY...
SATURDAY NIGHT...SW FLOW ALOFT WILL USHER IN A SERIES OF
DISTURBANCES FROM THE NORTHERN GULF INTO THE SOUTHERN
APPALACHIANS/MID-ATLANTIC REGION. LEAD DISTURBANCE PROJECTED TO
ADVANCE TOWARD OUR REGION LATE SATURDAY NIGHT. MID LEVEL FLOW WILL
GRADUALLY VEER IN RESPONSE TO THIS FEATURE...AIDING IN MOISTURE
TRANSPORT INTO THE REGION. SFC RIDGE IS EXPECTED TO REMAIN ALIGNED
WSW-ENE ACROSS CENTRAL NC...MAINTAINING A DRY AIR PRESENCE. LOW
LEVEL ISENTROPIC LIFT ANEMIC DURING THIS PERIOD SO APPEARS LIFT
GENERATED ALOFT FROM WAA. EXPECT DRY CONDITIONS THROUGH SATURDAY
EVENING WITH PATCHES OF LIGHT RAIN SHOWING UP ON THE RADAR AFTER
MIDNIGHT IN THE WEST. INITIAL PATCHES OF RAIN WILL GO TO MOISTEN THE
SUB CLOUD LAYER. THUS...BEST SHOT OF MEASURABLE RAIN WILL LIKELY BE
CONFINED TO THE FAR WESTERN-SOUTHERN PIEDMONT.
SUNDAY...ATMOSPHERE EXPECTED TO REMAIN ADEQUATELY MOIST TO MAINTAIN
CONSIDERABLE CLOUDINESS. LEAD PERTURBATION EXPECTED TO CROSS JUST
WEST-NW OF OUR REGION IN THE MORNING. BULK OF PRECIP WITH THIS
FEATURE SHOULD OCCUR IN VICINITY OF THE PIEDMONT COUNTIES WITH RAIN
COVERAGE DECREASING TO THE SE. WILL TREND POPS FROM LIKELY NW THIRD
TO CHANCE FAR SE. BY AFTERNOON...EXPECT NOTHING MORE THAN SPOTTY
PRECIP AT THIS TIME WITH CHANCE POPS AREAWIDE. MAX TEMPS SUNDAY
DEPENDENT ON AREAL EXTENT OF RAIN OR SHOWERS. FAVOR BLEND OF MOS
GUIDANCE (UPPER 50S NW TO LOW-MID 60S SE). MORE EXTENSIVE/LONGER
DURATION RAIN WILL RESULT IN COOLER TEMPS BY 3-4 DEGREES.
SUNDAY NIGHT...MODEL GUIDANCE HAS GAINED SOME CONSENSUS ON A
SLIGHTLY MORE PRONOUNCED PERTURBATION AND ATTENDANT SURFACE WAVE TO
AFFECT OUR REGION SUNDAY NIGHT...ESPECIALLY AFTER MIDNIGHT. MAIN
LIFTING MECHANISM APPEARS TO BE FROM A 140+ UPPER JET LIFTING NWD
ACROSS THE NORTHERN MID ATLANTIC...PLACING CENTRAL NC IN THE
FAVORABLE RIGHT ENTRANCE REGION. THIS MAY LEAD TO RAINFALL AMOUNTS
ON THE ORDER OF A HALF INCH OVER THE PIEDMONT. PLAN TO TREND POPS
FROM CHANCE IN THE EVENING TO HIGH LIKELY LATE SUNDAY NIGHT INTO THE
FIRST PART OF MONDAY MORNING. LOWS IN THE MID 40S NW TO LOWER 50S SE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 325 PM FRIDAY...
MONDAY THROUGH FRIDAY... PERTURBATION ALOFT AND ASSOCIATED SURFACE
WAVE AND FRONT WILL CROSS CENTRAL NC MONDAY MORNING. W-NW FLOW
BEHIND THE EXITING WEATHER SYSTEM MONDAY AFTERNOON-NIGHT WILL LEAD
TO DRIER AND MORE STABLE CONDITIONS. BASED ON CURRENT MODEL
TIMING...FAVOR HIGHEST POPS MONDAY MORNING WITH DECREASING POPS
MONDAY AFTERNOON AND LESS THAN 20 PERCENT POPS BY MONDAY NIGHT.
TEMPS MONDAY DEPENDENT UPON EVENTUAL TRACK OF THE SURFACE LOW. SOME
MODELS FAVOR A TRACK CLOSER TO THE NW PIEDMONT...PLACING BULK OF CWA
IN THE WARM SECTOR. OTHER MODELS CLUSTER AROUND A SOLUTION WITH THE
SFC WAVE CROSSING SC THEN UP ALONG THE NC COAST...PLACING CENTRAL NC
IN THE COOL SECTOR. THE LATER SOLUTION SEEMS MORE LIKELY CONSIDERING
THE POTENTIAL FOR A SHALLOW LAYER OF COOL AIR TO ADVECT INTO THE
REGION BEHIND THE INITIAL PERTURBATION. HAVE TRENDED MAX TEMPS A
LITTLE COOLER THAN MOS GUIDANCE BUT LATER FORECASTS MAY NEED TO
TREND COOLER.
TUESDAY THROUGH FRIDAY WILL FEATURE MAINLY DRY WEATHER WITH A
COOLING TREND AS BROAD UPPER LEVEL TROUGH COVERS THE U.S. THE WLY
FLOW ALOFT AND SFC HIGH PRESSURE DIVING SOUTHWARD ACROSS THE CENTRAL
U.S. NORMALLY SIGNALS DRY AND SEASONABLY COOL CONDITIONS FOR OUR
REGION. MAX TEMPS BY THE NEW YEAR WILL AVERAGE IN THE 40S TO NEAR 50
WITH MIN TEMPS IN THE 20S TO AROUND 30.
&&
.AVIATION /06Z SATURDAY THROUGH TUESDAY/...
AS OF 100 AM SATURDAY...
WITH DEWPOINTS SLIGHTLY HIGHER OVER THE COASTAL PLAIN AND LIGHT
WINDS...THERE MAY BE A COUPLE HOURS OF MVFR VSBY AT KRWI AND/OR KFAY
PRIOR TO 12Z...ESPECIALLY AS SKIES PARTIALLY CLEAR BETWEEN SOME HIGH
CLOUDS MOVING OVERHEAD. OTHERWISE.. VFR CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH THE TAF PERIOD WITH LIGHT WINDS BECOMING SOUTH-
SOUTHWESTERLY DURING THE DAY.
MID-LEVEL CLOUDS WILL INCREASE LATER TONIGHT AND EARLY SUNDAY AHEAD
OF A DISTURBANCE MOVING ALONG THE APPALACHIANS. HOWEVER...CURRENT
MODEL PROJECTIONS HAVE LOW CLOUDS AND SUB-VFR CEILINGS SPREADING
INTO THE KGSO/KINT VICINITY WELL AFTER 06Z SUNDAY.
LOOKING AHEAD: A SERIES OF UPPER-LEVEL DISTURBANCES MOVING SOUTHWEST
TO NORTHEAST ACROSS THE REGION COMBINED WITH AN APPROACHING FRONTAL
ZONE WILL BRING A COUPLE ROUNDS OF LIGHT PRECIP AND SUB-VFR
CONDITIONS TO PORTIONS OF CENTRAL NC SUNDAY AND MONDAY. CONDITIONS
ARE EXPECTED TO IMPROVE BY LATE MONDAY NIGHT INTO TUESDAY. -KRD
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...HARTFIELD/KRD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1237 PM CST SAT DEC 27 2014
.UPDATE...
ISSUED AT 1236 PM CST SAT DEC 27 2014
AREA OF LIGHT SNOW CONTINUES TO PUSH EAST OF THE VALLEY...AND
TIMING STILL LOOKS GOOD FOR MOVING IT OUT OF THE AREA BY 21Z.
THUS...WILL NOT MAKE ANY CHANGES FOR POPS/PCPN ATTM. REST OF
FORECAST CONTINUES TO LOOK GOOD.
UPDATE ISSUED AT 935 AM CST SAT DEC 27 2014
AREA OF LIGHT SNOW CONTINUES TO PUSH ACROSS THE NRN VALLEY SO WILL
KEEP POPS/PCPN AS IS FOR NOW. OTHERWISE...REST OF FORECAST ON
TARGET.
UPDATE ISSUED AT 710 AM CST SAT DEC 27 2014
WEAK RETURNS ASSOCIATED WITH LIGHT SNOW WHICH HAS MOVED ACROSS THE
HWY 2 CORRIDOR THE LAST 4 HOURS IS WEAKENING AS IT MOVES INTO THE
CWA...HOWEVER WE ARE SEEING REPORTS OF LIGHT SNOW (LIKELY
FLURRIES) FROM THE I 94 CORRIDOR NORTH. WILL CONTINUE FLURRIES FOR
AREAS OUTSIDE AREAS DEPICTED ON RADAR AND CONTINUE THE MENTION OF
MEASURABLE SNOW ACROSS THE FAR NORTH UNTIL MORNING SNOW REPORTS
COME IN...AS A TENTH OF AN INCH NOT OUT OF THE QUESTION BUT
CONFIDENCE IS DECREASING WITH LATEST RADAR TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1236 PM CST SAT DEC 27 2014
BRIEF BAND OF -SN JUST ABOUT THROUGH KGFK...VFR CIGS SHOULD
PREVAIL AT ALL SITES THROUGH THE AFTERNOON. COLD FRONT ON A MAINLY
NORTH TO SOUTH TRACK THROUGH REGION LATER TODAY THIS AFTN WILL
LIKELY BE ACCOMPANIED BY SEVERAL HOURS OF MVFR...INCLUDED -SHSN
ALL EXCEPT KFAR AT AND BEYOND FROPA. WINDS TO SHIFT TO N-NW BEHIND
FRONT REMAINING ARD 10 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...WJB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
936 AM CST SAT DEC 27 2014
.UPDATE...
ISSUED AT 935 AM CST SAT DEC 27 2014
AREA OF LIGHT SNOW CONTINUES TO PUSH ACROSS THE NRN VALLEY SO WILL
KEEP POPS/PCPN AS IS FOR NOW. OTHERWISE...REST OF FORECAST ON
TARGET.
UPDATE ISSUED AT 710 AM CST SAT DEC 27 2014
WEAK RETURNS ASSOCIATED WITH LIGHT SNOW WHICH HAS MOVED ACROSS THE
HWY 2 CORRIDOR THE LAST 4 HOURS IS WEAKENING AS IT MOVES INTO THE
CWA...HOWEVER WE ARE SEEING REPORTS OF LIGHT SNOW (LIKELY
FLURRIES) FROM THE I 94 CORRIDOR NORTH. WILL CONTINUE FLURRIES FOR
AREAS OUTSIDE AREAS DEPICTED ON RADAR AND CONTINUE THE MENTION OF
MEASURABLE SNOW ACROSS THE FAR NORTH UNTIL MORNING SNOW REPORTS
COME IN...AS A TENTH OF AN INCH NOT OUT OF THE QUESTION BUT
CONFIDENCE IS DECREASING WITH LATEST RADAR TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM CST SAT DEC 27 2014
MVFR CIGS WILL PERSIST THROUGH THE DAY IN NORTHWEST AND W CNTRL
MN...WHILE VFR CIGS MOVE ACROSS EASTERN ND. MOS GUIDANCE
INDICATING THOSE CIGS LOWERING INTO MVFR RANGE...BUT WILL HOLD OFF
UNTIL SFC WINDS SHIFT TO NORTH THIS EVENING AND LOWER CIGS OVER
SRN MB BEGIN ADVECTING SOUTH. FAR WILL BE CLEAR FOR MUCH OF THE
MORNING BEFORE VFR DECK ARRIVES IN THE LATE MORNING. DVL/TVF/GFK
MAY SEE SOME LIGHT FLURRIES THROUGH MID AFTN...BUT NO REDUCTIONS
TO VSBY EXPECTED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
710 AM CST SAT DEC 27 2014
.UPDATE...
ISSUED AT 710 AM CST SAT DEC 27 2014
WEAK RETURNS ASSOCIATED WITH LIGHT SNOW WHICH HAS MOVED ACROSS THE
HWY 2 CORRIDOR THE LAST 4 HOURS IS WEAKENING AS IT MOVES INTO THE
CWA...HOWEVER WE ARE SEEING REPORTS OF LIGHT SNOW (LIKELY
FLURRIES) FROM THE I 94 CORRIDOR NORTH. WILL CONTINUE FLURRIES FOR
AREAS OUTSIDE AREAS DEPICTED ON RADAR AND CONTINUE THE MENTION OF
MEASURABLE SNOW ACROSS THE FAR NORTH UNTIL MORNING SNOW REPORTS
COME IN...AS A TENTH OF AN INCH NOT OUT OF THE QUESTION BUT
CONFIDENCE IS DECREASING WITH LATEST RADAR TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM CST SAT DEC 27 2014
MVFR CIGS WILL PERSIST THROUGH THE DAY IN NORTHWEST AND W CNTRL
MN...WHILE VFR CIGS MOVE ACROSS EASTERN ND. MOS GUIDANCE
INDICATING THOSE CIGS LOWERING INTO MVFR RANGE...BUT WILL HOLD OFF
UNTIL SFC WINDS SHIFT TO NORTH THIS EVENING AND LOWER CIGS OVER
SRN MB BEGIN ADVECTING SOUTH. FAR WILL BE CLEAR FOR MUCH OF THE
MORNING BEFORE VFR DECK ARRIVES IN THE LATE MORNING. DVL/TVF/GFK
MAY SEE SOME LIGHT FLURRIES THROUGH MID AFTN...BUT NO REDUCTIONS
TO VSBY EXPECTED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
402 AM CST SAT DEC 27 2014
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1143 PM CST FRI DEC 26 2014
MVFR CONDITIONS CONTINUE AT KGFK...KTVF...AND KBJI ALONG WITH AN
ISOLATED FLURRY AT TIMES AT KBJI. KDVL IS CURRENTLY CLEAR BUT WILL
CLOUD UP IN THE NEXT HOUR OR SO AS CLOUDS MOVE IN FROM THE WEST.
CURRENT OBS OVER CENTRAL AND WESTERN ND HAVE THE LEADING EDGE OF
CLOUDS MAINLY IN THE 5000-7000 FT RANGE SO THINK VFR CONDITIONS
WILL CONTINUE A BIT LONGER. MVFR CIGS ARE FURTHER BEHIND
THOUGH...AND THINK ALL TAF SITES SHOULD GO DOWN IN CATEGORY BY MID
MORNING TOMORROW. THINK THAT THE STRATUS WILL STICK AROUND FOR THE
AFTERNOON AND EVENING. THE ARCTIC FRONT WILL BEGIN TO MOVE DOWN
INTO THE FORECAST AREA BY THE END OF THE PERIOD...WITH CLOUDS AND
EVEN SOME LIGHT SNOW POSSIBLE ALONG THE LEADING EDGE.
HOWEVER...UNCERTAIN WHERE THE SNOW WILL BE SO WILL LEAVE OUT FOR
NOW. MVFR CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1143 PM CST FRI DEC 26 2014
.UPDATE...
ISSUED AT 1143 PM CST FRI DEC 26 2014
SFC RIDGE AXIS HAS SETTLED OVER THE CENTER OF THE CWA...BUT THE
CLOUDS HAVE MOVED LITTLE FURTHER EASTWARD FROM THE RED RIVER AT
LEAST IN THE NORTHERN VALLEY. THERE ARE SOME MID LEVEL CLOUDS
STARTING TO MOVE INTO THE NORTHWESTERN COUNTIES...SO THE FREE FALL
OF BELOW ZERO TEMPS FROM DVL AND POINTS NORTH SHOULD START TO
LEVEL OFF. THINK THAT THE CLOUDS WILL CONTINUE TO MOVE EAST...WITH
THE WESTERN DECK FASTER AND POSSIBLY OVERTAKING THE EASTERN DECK
WHICH HAS BEEN SLOW TO BUDGE. CONTINUED TO KEEP SOME CLEARING IN
THE VALLEY TOWARDS MORNING BUT MAY HAVE TO ADJUST IF THE DRYING
NEVER MAKES IT INTO THE CENTRAL CWA.
UPDATE ISSUED AT 949 PM CST FRI DEC 26 2014
STRATUS HAS REMAINED OVER THE NORTHERN RED RIVER VALLEY AND IS
EVEN SPITTING OUT SOME MORE FLURRIES. MUCH OF THE WESTERN CWA HAS
REMAINED CLEAR AND SOME SPOTS IN THE NORTHWEST HAVE DROPPED DOWN
TO THE -5 TO -10 RANGE. THINK THAT THE COLDEST AREAS COULD BOTTOM
OUT AROUND -10 BUT CLOUDS ARE STARTING TO MOVE IN FROM THE WEST SO
THEY SHOULD SLOWLY START TO RISE AFTER MIDNIGHT. TRIED TO ADJUST
CLOUDS TO REFLECT CURRENT TRENDS AND FOLLOW THE RAP WHICH HAS BEEN
NOT TOO FAR OFF...THE CLEAR AREA MOVING EAST INTO THE VALLEY
TOWARDS MORNING WHILE THE WEST CLOUDS UP AGAIN. EXTENDED THE
FLURRY MENTION...PUTTING ISOLATED OR SCATTERED WHEREVER THE CLOUDS
ARE OVERNIGHT.
UPDATE ISSUED AT 655 PM CST FRI DEC 26 2014
CLOUDS WILL BE THE MAIN ISSUE...AS THE NORTHERN VALLEY HAS SEEN A
BIT MORE CLOUDS MOVING DOWN OUT OF CANADA...BUT THE WEST CONTINUES
TO BE CLEAR. TEMPS JUST NORTH OF LANGDON ARE ALREADY DOWN AROUND
MINUS 8...SO THINK PREVIOUS SHIFTS IDEA OF A SHARP DROP OFF AND
THEN RISING TEMPS LATER ON AS MORE CLOUDS COME IN FROM THE WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 305 PM CST FRI DEC 26 2014
HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT. CLOUDS HAVE BEEN
SLOW TO CLEAR FROM THE NORTHWEST...BUT THE CLEARING CONTINUES TO
MAKE PROGRESS FROM WEST TO EAST. RAP/HRRR GUIDANCE CLEARS AREAS
ALONG AND WEST OF THE VALLEY BY THIS EVENING...BUT KEEPS AREAS
EAST OF THE VALLEY CLOUDY THROUGH THE OVERNIGHT. TRENDED SLOWER
WITH THE CLEARING EAST OF THE VALLEY...BUT STILL KEPT THE IDEA
FOR CLEARING BY MORNING (LATER UPDATES WILL NEED TO EVALUATE IF
THE HRRR/RAP IDEA MIGHT BE BETTER). MIN TEMPERATURES WILL BE EVEN
TRICKIER...MUCH DEPENDENT ON CLOUD COVER. THERE SHOULD BE A QUICK
DROP THIS EVENING WHERE SKY IS CLEAR...BUT WARM AIR
ADVECTION/RETURN FLOW KICKS IN AFTER MIDNIGHT WHICH SHOULD STEADY
OR SLOWLY RISE TEMPS (AT LEAST FOR THE DVL BASIN...NOT SURE ABOUT
VALLEY LOCATIONS).
COLD FRONT POISED TO DROP THROUGH THE FA SATURDAY NIGHT. ONE LAST
WARMER DAY ON SATURDAY AHEAD OF THIS FEATURE...WITH CLOUDS
INCREASING FROM NORTH TO SOUTH. THIS FROPA WILL BE ASSOCIATED WITH
WEAK FORCING...SO ISOLD SNOW SHOWERS/FLURRIES POSSIBLE. MODELS
INDICATE THAT COLD AIR ADVECTION WILL BE RELATIVELY WEAK...LEADING
TO A SHALLOW MIXING LAYER WITH 15-20 KNOTS AVAILABLE TO MIX
(WINDS MAYBE BREEZY...BUT NOT STRONG).
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 305 PM CST FRI DEC 26 2014
SUNDAY-MONDAY NIGHT...COLD AIR ADVECTION REGIME WITH HIGH
PRESSURE BUILDING INTO THE REGION. TEMPERATURES WILL BE MUCH
COLDER THAN THE PREVIOUS COUPLE WEEKS...WITH MAX TEMPS MAINLY IN
THE SINGLE DIGITS (ABOVE OR BELOW ZERO)...AND MIN TEMPS MAINLY
BELOW ZERO. THE MAIN CONCERN THIS PERIOD WILL BE WIND CHILL
VALUES. THE STRONGEST AREA OF HIGH PRESSURE WILL TRACK ACROSS THE
WESTERN DAKOTAS...KEEPING THIS REGION WITHIN A WEAK SFC PRESSURE
GRADIENT. THIS SHOULD BE ENOUGH FOR WIND SPEEDS AOA 5 KNOTS SUNDAY
NIGHT AND MONDAY NIGHT WHEN TEMPERATURES WILL BE THE COLDEST
(LEADING TO POTENTIAL WIND CHILL ADVISORY CONDITIONS).
TUESDAY-FRIDAY...LONG WAVE RIDGE FORECAST TO REMAIN OVER WESTERN
NORTH AMERICA INTO AK WHILE LONG WAVE TROUGH EXTENDS FROM HUDSON
BAY TO THE DESERT SOUTHWEST. LONG WAVE TROUGH SHIFTS OVER EASTERN
NORTH AMERICA BY THE END OF THE PERIOD. LONG WAVE UPPER RIDGE
DEAMPLIFIES WHILE LONG WAVE TROUGH OVER HUDSON BAY AMPLIFIES
THROUGH THE PERIOD.
ECMWF AND GFS WERE IN GOOD AGREEMENT AT THE BEGINNING OF THE PERIOD.
THE GFS WAS A LITTLE FASTER AND BECOMES FASTER THAN THE ECMWF FOR
THE REST OF THE PERIOD. WILL PREFER THE SLOWER ECMWF.
WILL SPLIT THE DIFFERENCE BETWEEN POPS FROM THIS MORNINGS PACKAGE
AND POPS FOR THIS AFTERNOONS RUN FOR WED NIGHT AND THU.
A COLD DAY TO START ON TUE. SOME MODERATION ON WED AND THU, THEN BACK
INTO ARCTIC AIR ON FRI. HIGH TEMPS WERE GENERALLY INCREASED A DEGREE
OR TWO FOR TUE AND WED, INCREASED ONE TO FOUR DEGREES ON THU AND
LITTLE CHANGE ON FRI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1143 PM CST FRI DEC 26 2014
MVFR CONDITIONS CONTINUE AT KGFK...KTVF...AND KBJI ALONG WITH AN
ISOLATED FLURRY AT TIMES AT KBJI. KDVL IS CURRENTLY CLEAR BUT WILL
CLOUD UP IN THE NEXT HOUR OR SO AS CLOUDS MOVE IN FROM THE WEST.
CURRENT OBS OVER CENTRAL AND WESTERN ND HAVE THE LEADING EDGE OF
CLOUDS MAINLY IN THE 5000-7000 FT RANGE SO THINK VFR CONDITIONS
WILL CONTINUE A BIT LONGER. MVFR CIGS ARE FURTHER BEHIND
THOUGH...AND THINK ALL TAF SITES SHOULD GO DOWN IN CATEGORY BY MID
MORNING TOMORROW. THINK THAT THE STRATUS WILL STICK AROUND FOR THE
AFTERNOON AND EVENING. THE ARCTIC FRONT WILL BEGIN TO MOVE DOWN
INTO THE FORECAST AREA BY THE END OF THE PERIOD...WITH CLOUDS AND
EVEN SOME LIGHT SNOW POSSIBLE ALONG THE LEADING EDGE.
HOWEVER...UNCERTAIN WHERE THE SNOW WILL BE SO WILL LEAVE OUT FOR
NOW. MVFR CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...JR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1245 PM EST SAT DEC 27 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES TODAY AND DRAG A
COLD FRONT ACROSS THE AREA LATE TODAY AND TONIGHT. A SECOND COLD
FRONT IS EXPECTED LATE MONDAY INTO TUESDAY. HIGH PRESSURE FROM
CANADA WILL BUILD IN FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE INITIAL WAVE OF PRECIPITATION IN ADVANCE OF THE COLD FRONT HAS
BECOME WIDELY SCATTERED AND LIGHT OVER THE FORECAST AREA. WITH THE
FRONT STILL WELL TO THE WEST AND THE LACK OF SUPPORT...I EXPECT THIS
TREND TO CONTINUE. I WILL PULL BACK THE POPS FOR THIS AFTERNOON
PARTICULARLY OVER THE EASTERN SECTIONS OF THE AREA. SHOWERS WILL
BE IN THE AREA BUT WILL REMAIN WIDELY SCATTERED. A LITTLE BETTER
CHANCE FOR PRECIP OVER THE WESTERN COUNTIES BUT I WILL REDUCE THE
POPS SLIGHTLY IN THAT AREA AS WELL. I EXPECT THE BULK OF THE
PRECIPITATION WITH THE FRONTAL PASSAGE 00Z-06Z TIME FRAME. SOME
SUN OVER THE EASTERN PARTS OF THE FORECAST AREA ARE ALLOWING
TEMPERATURES TO QUICKLY RISE INTO THE 50S. SLIGHT WARM AIR
ADVECTION IN THIS AREA WILL ALLOW TEMPERATURES TO CONTINUE TO
RISE. 15Z RUC PUSHES TEMPERATURES INTO THE MID 50S FOR SEVERAL
LOCATIONS. I WILL RAISE TEMPERATURES A FEW DEGREES OVER THE EAST.
PREVIOUS DISCUSSION...
FIRST BAND OF PRECIP JUST WEST OF THE AREA SHOULD MOVE THROUGH
WEST TO EAST THIS MORNING AND EARLY THIS AFTERNOON...POSSIBLY
BECOMING MORE SPOTTY EAST AS SURFACE LOW MOVES FURTHER NORTHEAST
OVER THE CENTRAL GREAT LAKES. BEHIND THE BAND SHOULD COME A BIT OF
A BREAK IN THE PRECIP. LATE THIS AFTERNOON AND EVENING EXPECTING
NOW ANOTHER SURGE OF MOISTURE/PRECIP OUT OF THE SOUTHWEST AHEAD OF
THE COLD FRONT. THIS SHOULD SPREAD RAIN ACROSS THE ENTIRE AREA
FIRST HALF OF THE NIGHT AFTER WHICH WE SHOULD SEE DRYING FROM THE
NORTHWEST WITH DRY AIR AND SUBSIDENCE BEHIND THE FRONT. ADJUSTED
GRIDS TODAY AND TONIGHT TO REFLECT THIS.
ORIGINAL...LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE GREAT
LAKES TODAY. A COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE
THROUGH THE AREA THIS EVENING AND OVERNIGHT. MODELS DIFFER A BIT
ON TIMING OF THE PRECIP WITH THE GFS AHEAD OF THE NAM INITIALLY.
WILL SIDE CLOSER TO THE GFS HERE AND BRING CHANCE POPS INTO THE
WEST THIRD THROUGH THE MORNING. FOR THE AFTERNOON WILL INCREASE
POPS WEST TO LIKELY WITH CHANCE POPS MOST ELSEWHERE. HIGHS AROUND
50 REASONABLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
COLD FRONT CONTINUES SOUTHEAST THROUGH THE AREA OVERNIGHT. MODEL
DIFFERENCES CONTINUE WITH THE NAM BECOMING FASTER THAN THE GFS BY
SUNDAY MORNING...TAKING THE MOISTURE SOUTHEAST OUT OF THE AREA
WHILE THE GFS HANGS IT UP ACROSS THE SOUTHEAST THIRD OF THE AREA.
FEEL THAT MOISTURE WILL EXIT THE AREA QUICKLY BUT ALSO LIKELY
PRUDENT TO LEAVE A SMALL CHANCE POP THROUGH THE MORNING SUNDAY
SOUTHEAST BEFORE DRYING OUT COMPLETELY. PTYPE COULD BE AN ISSUE
WITH PRECIP POSSIBLE MIXING/CHANGING JUST BEFORE OR AS IT ENDS BUT
FOR NOW WILL LEAVE AS MOSTLY RAIN. SUNDAY SHOULD REMAIN DRY. SOME
CONCERN ABOUT HOW MUCH CLEARING OCCURS. INVERSION STRONG ENOUGH
BUT BUFKIT SHOWS LESS LOW LEVEL MOISTURE AS PREVIOUS EVENTS.
THINKING BEST CHANCE FOR CLEARING WILL BE NORTHWEST THIRD TO HALF
SO WILL HAVE THE AFTERNOON BECOMING PARTLY SUNNY/PARTLY CLOUDY
THERE. BREAKS POSSIBLE ELSEWHERE AS WELL. MONDAY INTO TUESDAY TWO
SYSTEMS COULD AFFECT THE AREA. FIRST IS A COASTAL LOW THAT
DEVELOPS IN THE GULF COAST AND MOVES NORTHEAST UP THE EAST COAST.
THE NAM SUGGESTS WE GET CLIPPED BY THE MOISTURE WHILE THE GFS
KEEPS IT TO OUR EAST. THE MORE PROBABLE SYSTEM TO AFFECT THE AREA
IS A COLD FRONT THAT WILL DROP SOUTH ACROSS THE AREA LATE MONDAY
AND TUESDAY. WOULD EXPECT SOME SNOW SHOWERS WITH THE FRONT WITH
-SOME- LAKE EFFECT BEHIND AS THE COLD AIR DEEPENS. HIGHS IN THE
UPPER 30S TO NEAR 40 SUNDAY...MID 30S MONDAY AND 20S TO NEAR 30 ON
TAP TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BE SITUATED ACROSS THE MID MISSISSIPPI AND LOWER
OHIO VALLEYS WEDNESDAY WITH LOW PRESSURE OVER HUDSON BAY. THIS IS
FAIRLY WELL AGREED UPON. A COLD FRONT WILL COME DOWN FROM WESTERN
CANADA AND THE NORTHERN PLAINS AND WILL MOVE ACROSS THE GREAT LAKES
IF NOT WEDNESDAY THAN THURSDAY. THIS WILL ALLOW THE GRADUAL
INFILTRATION OF COLDER AIR SOUTH INTO THE AREA WEDNESDAY AND
THURSDAY. AREAS OUTSIDE OF THE TRADITIONAL SNOWBELT SHOULD REMAIN
PRECIP FREE WITH HIGH PRESSURE SOUTH OF THE AREA AND LIMITED
MOISTURE WITH THE FRONT. DEPENDING ON THE AMOUNT OF MOISTURE
AVAILABLE AND EXACT BOUNDARY LAYER FLOW...LAKE EFFECT SNOW SHOWERS
POSSIBLE. WILL KEEP THE LOW CHANCE MENTION FOR NOW WEDNESDAY.
FORECAST GETS MORE COMPLICATED GOING INTO THE WEEKEND. OPERATIONAL
RUNS OF THE GFS AND ECMWF SHOW THE BEGINNINGS OF THE DEVELOPMENT OF
LOW PRESSURE THAT WOULD TRACK INTO THE OHIO VALLEY SATURDAY. THAT
WOULD BRING A SLIGHT MODIFICATION OF TEMPERATURES FRIDAY AND
THE POSSIBILITY OF PRECIPITATION EXPANDING NORTH INTO THE AREA. A
LOT OF VARIABILITY WITH THIS AND THE GFSENS AND ECMWF ENS BOTH HAVE
LOW PRESSURE FURTHER WEST AT 12Z SAT. THEREFORE WAITED UNTIL FRIDAY
NIGHT TO BRING THE CHANCE OF PRECIP INTO THE AREA. PRECIP TYPE MAY
BE A CONCERN.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND BRING A
CHANCE OF RAIN TAPERING TO WIDELY SCATTERED SHOWERS BY MORNING.
I ANTICIPATE THE CONDITIONS TO BECOME MAINLY MVFR TURNING TO
POSSIBLY TO IFR CONDITIONS THIS EVENING AND CONTINUING OVERNIGHT.
SOME WESTERN OHIO TAF SITES ARE ALREADY MVFR WITH MORE MVFR/IFR
CONDITIONS READY TO MOVE INTO THE FORECAST AREA OF OHIO AND NW
PENNSYLVANIA THIS EVENING.
WINDS SOUTHWEST THIS EVENING AND THEN WEST-NORTHWEST AFTER THE
FRONTAL PASSAGE WHICH IS EXPECTED BETWEEN 00Z SUN AND 09Z SUN.
.OUTLOOK...NON-VFR EXITING SUNDAY. NON-VFR MAINLY OVER NE OH/NW
PA MONDAY...THEN POSSIBLY MORE NON-VFR CONDITIONS OVER THE
ENTIRE AREA TUESDAY. WEDNESDAY NON-VFR POSSIBLE JUST ACROSS NE
OH/NW PA.
&&
.MARINE...
SOUTHERLY FLOW ON THE LAKE WILL TURN MORE SOUTHWESTERLY AND THEN
WEST-NORTHWEST TONIGHT WITH THE PASSAGE OF A COLD FRONT. WINDS
INCREASE ENOUGH FOR A SMALL CRAFT ADVISORY FOR THE EASTERN TWO
THIRDS THROUGH MIDDAY SUNDAY. A RIDGE BUILDS OVER THE LAKE QUICKLY
ON SUNDAY DIMINISHING WINDS/WAVES. AN EXPANSIVE AREA OF HIGH
PRESSURE WILL SHIFT FROM WESTERN CANADA TO THE CENTRAL PLAINS MONDAY
THROUGH WEDNESDAY. MEANWHILE LOW PRESSURE WILL BE MAKING ITS WAY
SOUTH TO HUDSON BAY WEDNESDAY...INCREASING GRADIENT BETWEEN THE TWO
FEATURES. THEREFORE WEST TO SOUTHWEST WINDS WILL INCREASE ON THE
LAKE. SMALL CRAFT ADVISORIES LIKELY AGAIN FOR MID WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
SUNDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...GARNET/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...BC
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1220 PM EST SAT DEC 27 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES TODAY AND DRAG A
COLD FRONT ACROSS THE AREA LATE TODAY AND TONIGHT. A SECOND COLD
FRONT IS EXPECTED LATE MONDAY INTO TUESDAY. HIGH PRESSURE FROM
CANADA WILL BUILD IN FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE INITIAL WAVE OF PRECIPITATION IN ADVANCE OF THE COLD FRONT HAS
BECOME WIDELY SCATTERED AND LIGHT OVER THE FORECAST AREA. WITH THE
FRONT STILL WELL TO THE WEST AND THE LACK OF SUPPORT...I EXPECT THIS
TREND TO CONTINUE. I WILL PULL BACK THE POPS FOR THIS AFTERNOON
PARTICULARLY OVER THE EASTERN SECTIONS OF THE AREA. SHOWERS WILL
BE IN THE AREA BUT WILL REMAIN WIDELY SCATTERED. A LITTLE BETTER
CHANCE FOR PRECIP OVER THE WESTERN COUNTIES BUT I WILL REDUCE THE
POPS SLIGHTLY IN THAT AREA AS WELL. I EXPECT THE BULK OF THE
PRECIPITATION WITH THE FRONTAL PASSAGE 00Z-06Z TIME FRAME. SOME
SUN OVER THE EASTERN PARTS OF THE FORECAST AREA ARE ALLOWING
TEMPERATURES TO QUICKLY RISE INTO THE 50S. SLIGHT WARM AIR
ADVECTION IN THIS AREA WILL ALLOW TEMPERATURES TO CONTINUE TO
RISE. 15Z RUC PUSHES TEMPERATURES INTO THE MID 50S FOR SEVERAL
LOCATIONS. I WILL RAISE TEMPERATURES A FEW DEGREES OVER THE EAST.
PREVIOUS DISCUSSION...
FIRST BAND OF PRECIP JUST WEST OF THE AREA SHOULD MOVE THROUGH
WEST TO EAST THIS MORNING AND EARLY THIS AFTERNOON...POSSIBLY
BECOMING MORE SPOTTY EAST AS SURFACE LOW MOVES FURTHER NORTHEAST
OVER THE CENTRAL GREAT LAKES. BEHIND THE BAND SHOULD COME A BIT OF
A BREAK IN THE PRECIP. LATE THIS AFTERNOON AND EVENING EXPECTING
NOW ANOTHER SURGE OF MOISTURE/PRECIP OUT OF THE SOUTHWEST AHEAD OF
THE COLD FRONT. THIS SHOULD SPREAD RAIN ACROSS THE ENTIRE AREA
FIRST HALF OF THE NIGHT AFTER WHICH WE SHOULD SEE DRYING FROM THE
NORTHWEST WITH DRY AIR AND SUBSIDENCE BEHIND THE FRONT. ADJUSTED
GRIDS TODAY AND TONIGHT TO REFLECT THIS.
ORIGINAL...LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE GREAT
LAKES TODAY. A COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE
THROUGH THE AREA THIS EVENING AND OVERNIGHT. MODELS DIFFER A BIT
ON TIMING OF THE PRECIP WITH THE GFS AHEAD OF THE NAM INITIALLY.
WILL SIDE CLOSER TO THE GFS HERE AND BRING CHANCE POPS INTO THE
WEST THIRD THROUGH THE MORNING. FOR THE AFTERNOON WILL INCREASE
POPS WEST TO LIKELY WITH CHANCE POPS MOST ELSEWHERE. HIGHS AROUND
50 REASONABLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
COLD FRONT CONTINUES SOUTHEAST THROUGH THE AREA OVERNIGHT. MODEL
DIFFERENCES CONTINUE WITH THE NAM BECOMING FASTER THAN THE GFS BY
SUNDAY MORNING...TAKING THE MOISTURE SOUTHEAST OUT OF THE AREA
WHILE THE GFS HANGS IT UP ACROSS THE SOUTHEAST THIRD OF THE AREA.
FEEL THAT MOISTURE WILL EXIT THE AREA QUICKLY BUT ALSO LIKELY
PRUDENT TO LEAVE A SMALL CHANCE POP THROUGH THE MORNING SUNDAY
SOUTHEAST BEFORE DRYING OUT COMPLETELY. PTYPE COULD BE AN ISSUE
WITH PRECIP POSSIBLE MIXING/CHANGING JUST BEFORE OR AS IT ENDS BUT
FOR NOW WILL LEAVE AS MOSTLY RAIN. SUNDAY SHOULD REMAIN DRY. SOME
CONCERN ABOUT HOW MUCH CLEARING OCCURS. INVERSION STRONG ENOUGH
BUT BUFKIT SHOWS LESS LOW LEVEL MOISTURE AS PREVIOUS EVENTS.
THINKING BEST CHANCE FOR CLEARING WILL BE NORTHWEST THIRD TO HALF
SO WILL HAVE THE AFTERNOON BECOMING PARTLY SUNNY/PARTLY CLOUDY
THERE. BREAKS POSSIBLE ELSEWHERE AS WELL. MONDAY INTO TUESDAY TWO
SYSTEMS COULD AFFECT THE AREA. FIRST IS A COASTAL LOW THAT
DEVELOPS IN THE GULF COAST AND MOVES NORTHEAST UP THE EAST COAST.
THE NAM SUGGESTS WE GET CLIPPED BY THE MOISTURE WHILE THE GFS
KEEPS IT TO OUR EAST. THE MORE PROBABLE SYSTEM TO AFFECT THE AREA
IS A COLD FRONT THAT WILL DROP SOUTH ACROSS THE AREA LATE MONDAY
AND TUESDAY. WOULD EXPECT SOME SNOW SHOWERS WITH THE FRONT WITH
-SOME- LAKE EFFECT BEHIND AS THE COLD AIR DEEPENS. HIGHS IN THE
UPPER 30S TO NEAR 40 SUNDAY...MID 30S MONDAY AND 20S TO NEAR 30 ON
TAP TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BE SITUATED ACROSS THE MID MISSISSIPPI AND LOWER
OHIO VALLEYS WEDNESDAY WITH LOW PRESSURE OVER HUDSON BAY. THIS IS
FAIRLY WELL AGREED UPON. A COLD FRONT WILL COME DOWN FROM WESTERN
CANADA AND THE NORTHERN PLAINS AND WILL MOVE ACROSS THE GREAT LAKES
IF NOT WEDNESDAY THAN THURSDAY. THIS WILL ALLOW THE GRADUAL
INFILTRATION OF COLDER AIR SOUTH INTO THE AREA WEDNESDAY AND
THURSDAY. AREAS OUTSIDE OF THE TRADITIONAL SNOWBELT SHOULD REMAIN
PRECIP FREE WITH HIGH PRESSURE SOUTH OF THE AREA AND LIMITED
MOISTURE WITH THE FRONT. DEPENDING ON THE AMOUNT OF MOISTURE
AVAILABLE AND EXACT BOUNDARY LAYER FLOW...LAKE EFFECT SNOW SHOWERS
POSSIBLE. WILL KEEP THE LOW CHANCE MENTION FOR NOW WEDNESDAY.
FORECAST GETS MORE COMPLICATED GOING INTO THE WEEKEND. OPERATIONAL
RUNS OF THE GFS AND ECMWF SHOW THE BEGINNINGS OF THE DEVELOPMENT OF
LOW PRESSURE THAT WOULD TRACK INTO THE OHIO VALLEY SATURDAY. THAT
WOULD BRING A SLIGHT MODIFICATION OF TEMPERATURES FRIDAY AND
THE POSSIBILITY OF PRECIPITATION EXPANDING NORTH INTO THE AREA. A
LOT OF VARIABILITY WITH THIS AND THE GFSENS AND ECMWF ENS BOTH HAVE
LOW PRESSURE FURTHER WEST AT 12Z SAT. THEREFORE WAITED UNTIL FRIDAY
NIGHT TO BRING THE CHANCE OF PRECIP INTO THE AREA. PRECIP TYPE MAY
BE A CONCERN.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
FIRST WAVE OF SHOWERS TO WORK ACROSS THE AREA THIS MORNING AND
LAST ABOUT 2-3 HOURS. UNSURE HOW FAR EAST THEY WILL GET...POSSIBLY
DRYING UP BEFORE THEY REACH THE EASTERN TAF SITES. COULD SEE SOME
MVFR WITH THESE. VFR FOR THE MIDDLE PORTION OF THE DAY EXCEPT FOR
KTOL/KFDY. FOR TONIGHT COLD FRONT CROSSES. EXPECT SHOWERS WITH
WIDESPREAD MVFR CONDITIONS AND AREAS OF IFR TO SPREAD FROM WEST TO
EAST STARTING LATE THIS AFTERNOON FOR KTOL AND KFDY. THESE SHOWERS
WILL BE PROGRESSIVE AS WELL AND WILL BE EXITING THE AREA CLOSE TO
12Z SUN. SOUTHERLY WINDS THIS MORNING WILL VEER SOUTHWEST AND THEN
WEST- NORTHWEST AFTER THE FRONTAL PASSAGE WHICH IS EXPECTED
BETWEEN 00Z SUN AND 09Z SUN.
.OUTLOOK...NON-VFR EXITING SUNDAY. NON-VFR MAINLY OVER NE OH/NW
PA MONDAY...THEN POSSIBLY OVER THE ENTIRE AREA TUESDAY. WEDNESDAY
NON-VFR POSSIBLE ACROSS NE OH/NW PA.
&&
.MARINE...
SOUTHERLY FLOW ON THE LAKE WILL TURN MORE SOUTHWESTERLY AND THEN
WEST-NORTHWEST TONIGHT WITH THE PASSAGE OF A COLD FRONT. WINDS
INCREASE ENOUGH FOR A SMALL CRAFT ADVISORY FOR THE EASTERN TWO
THIRDS THROUGH MIDDAY SUNDAY. A RIDGE BUILDS OVER THE LAKE QUICKLY
ON SUNDAY DIMINISHING WINDS/WAVES. AN EXPANSIVE AREA OF HIGH
PRESSURE WILL SHIFT FROM WESTERN CANADA TO THE CENTRAL PLAINS MONDAY
THROUGH WEDNESDAY. MEANWHILE LOW PRESSURE WILL BE MAKING ITS WAY
SOUTH TO HUDSON BAY WEDNESDAY...INCREASING GRADIENT BETWEEN THE TWO
FEATURES. THEREFORE WEST TO SOUTHWEST WINDS WILL INCREASE ON THE
LAKE. SMALL CRAFT ADVISORIES LIKELY AGAIN FOR MID WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
SUNDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...GARNET/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1101 AM EST SAT DEC 27 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TONIGHT BRINGING A CHANCE
OF PRECIPITATION TODAY INTO SUNDAY. HIGH PRESSURE WILL BRING
COOLER MORE SEASONABLE TEMPERATURES TO REGION FOR THE FIRST PART
OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONFIDENCE IN COVERAGE AND TIMING OF PRECIPITATION IS FAIRLY
LOW...UTILIZING HRRR SOLUTION FOR NOW WHICH DOES DEPICT THE LULL
AND SLOWER TIMING OF PRECIP ONSET WITH THE SECOND WAVE LATE THIS
AFTERNOON. WHILE SHOWERS NOT YET DEVELOPING TO OUR WEST AND
SW...STILL ANTICIPATION OF ISENTROPIC LIFT AHEAD OF THE FRONT TO
GENERATE SCATTERED AND THEN MORE WIDESPREAD COVERAGE AFTER 18Z.
HAVE RAISED TEMPS SLIGHTLY WITH THE WAA AND THE BREAK IN THE
RAINFALL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
AS CDFNT PUSHES ACROSS THE FA TONIGHT WILL KEEP MENTION OF
CATEGORICAL POPS. COLDER AIR WORKING IN ON THE BACKSIDE OF THE
SYSTEM WILL CAUSE SOME SNOW TO MIX IN LATE TONIGHT INTO SUNDAY
MORNING.
WHILE INITIAL ENERGY MOVES THROUGH THE GREAT LAKES...THE
REMAINDER OF THE UPPER TROF WILL SLOWLY EJECT OUT OF ROCKIES. THIS
CAUSES THE FRONT AND THE BACK EDGE OF THE PCPN TO HANG UP FOR
SUNDAY. KEPT LIKELY POPS SE OF 71 FOR SUNDAY MORNING...WITH THE
EXTREME NW COUNTIES BEING DRY. SHEARED OUT TROF SWINGS THROUGH ON
SUNDAY FINALLY PULLING THE PCPN OUT OF THE REGION BY SUNDAY
EVENING.
HIGH PRESSURE WILL TRY AND NOSE IN FROM THE NORTH SUNDAY NIGHT
INTO MONDAY. A MODEL OR TWO IS HINTING AT SOME SPOTTY PCPN IN THE
CAA MONDAY. THINK THIS IS OVERDONE...SO LEFT THE FORECAST DRY FOR NOW.
TEMPERATURES WILL REMAIN ABOVE FREEZING TONIGHT...RANGING FROM THE
MID 30S INT HE NW TO THE MID 40S IN THE SE. TEMPERATURE WILL ONLY
RECOVER A FEW DEGREES ON SUNDAY AS THE COOLER AIR WORKS IN.
TEMPERATURES WILL BE MORE SEASONAL ON MONDAY WITH HIGHS IN THE MID
30S TO LOWER 40S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ANOTHER SHORTWAVE WILL ROTATE THROUGH THE GREAT LAKES MONDAY
NIGHT AND TUESDAY. THIS FEATURE WILL PUSH A SURFACE COLD FRONT
THROUGH THE AREA ON TUESDAY...THOUGH A RELATIVELY DRY AIRMASS WILL
PRECLUDE MUCH IN THE WAY OF PRECIPITATION. ANYTHING THAT DOES
OCCUR SHOULD BE IN THE FORM OF LIGHT SNOW SHOWERS OR A MIXTURE OF
LIGHT RAIN AND SNOW SHOWERS.
WEDNESDAY AND THURSDAY ARE EXPECTED TO BE DRY...WITH NEAR TO
SLIGHTLY BELOW NORMAL TEMPERATURES ACROSS THE AREA. THE SOUTHWEST
TROUGH IS PROGGED TO EJECT INTO THE WESTERN PLAINS STATES AT THE END
OF THE WEEK...RESULTING IN AN INCREASING CHANCE FOR PRECIPITATION
ACROSS THE OHIO VALLEY ON FRIDAY.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
SHORT RANGE MODELS CONTINUE TO SHOW THE BAND OF SHOWERS THAT WILL
PUSH INTO TAF SITES DISSIPATING THIS MORNING. WAS NOT SURE OF THE
VERACITY OF THESE MODELS BUT EVEN WITH THE LINE OF SHOWERS HOLDING
TOGETHER IT WOULD ONLY CONSTITUTE A 2 HOUR OR SO BLOCK OF TIME
WITH SHOWER ACTIVITY FROM A VFR CLOUD DECK. THE WORST OF THIS
MORNINGS ROUND OF SHOWERS WOULD DROP CIGS/VSBYS TO THE HIGHER END
OF MVFR AND THEN COME BACK UP TO VFR UNTIL THE NEXT ROUND OCCURS
AHEAD OF THE COLD FRONT. COLD FRONT WILL SWITCH WINDS TO NW AND
THEN N OVERNIGHT...WITH FROPA HAPPENING TOWARDS OR A LITTLE AFTER
MIDNIGHT TONIGHT.
LOWER MVFR AND SOME IFR CIGS ARE EXPECTED TONIGHT AS THE AMOUNT OF
AVAILABLE MOISTURE INCREASES AND SHOWERS BECOME MORE NUMEROUS
AHEAD OF THE FRONT THIS LATE DAY AND EVENING. RAIN WILL END NW-SE
ON SUNDAY AND CIGS WILL LIFT SOMEWHAT THROUGH THE DAY.
OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE THROUGH EARLY SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...SITES
NEAR TERM...JDR
SHORT TERM...SITES
LONG TERM...SHOBE2
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS TULSA OK
908 PM CST SUN DEC 28 2014
.DISCUSSION...
THE DIFFERENCE FIELD BETWEEN THE 11.0 MICRON AND 3.9 MICRON
INFRA-RED SATELLITE DATA SHOWS LOW CLOUDS HOLDING OVER THE
SOUTHEAST TIP OF OKLAHOMA THIS EVENING. AS THE LOW-LEVEL FLOW
BECOMES LIGHT SOUTHEASTERLY THE CLOUDS SHOULD HAVE A TENDENCY TO
EXPAND NORTHWEST SOME AND HAVE SHOWN AN INCREASE IN CLOUDS LATER
TONIGHT IN FAR SOUTHEAST OKLAHOMA.
ALSO INTERESTING IS THE CURRENT SURFACE RELATIVE HUMIDITY FIELD
SHOWING READINGS AT JUST BEFORE 03Z IN THE UPPER 90S AT A FEW
MESONET SITES IN SOUTHEAST OKLAHOMA AND IN THE MID 90S OVER THE
OLD NARROW SNOW FIELD IN NORTHEAST OKLAHOMA. WITH LIGHT MOISTURE
ADVECTION DEVELOPING IN THE SOUTHEASTERLY SURFACE FLOW... THESE
AREAS WHERE THE HUMIDITY IS ALREADY HIGH WILL BE FAVORED FOR
PATCHY DENSE FOG FORMATION. NOT OVERLY CONFIDENT ABOUT THE
EVOLUTION OR COVERAGE...BUT IT IS WORTH SHOWING IN THE FORECAST
TEXT AND GRIDS. THE HRRR IS LIKELY OVERLY DRAMATIC...BUT IT SHOWS
VERY INTERESTING MESOSCALE TEMPERATURE...WIND AND HUMIDITY
EVOLUTIONS OVER THE OLD SNOW FIELD...WITH FOG ADVECTING NORTHWEST
SLOWLY LATER TONIGHT FROM THE OLD SNOW COVERED AREA.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...08
AREA FORECAST DISCUSSION
NWS NORMAN OK
129 AM CST SAT DEC 27 2014
.UPDATE...
UPDATE TO PRECIP/WX THROUGH 12Z...
&&
.DISCUSSION...
QUICK MORNING UPDATE FOR PRECIP/WX THROUGH 12Z THIS MORNING.
OBSERVING RADAR TRENDS AND LIMITED REPORTS FROM MPING THIS AM...
THE NARROW LINE OF PRECIP THAT HAS DEVELOPED BETWEEN THE I-44 AND
I-35 CORRIDORS IS PRIMARILY RAIN... WITH SOME SLEET/SNOW MIXED
IN. A FEW MPING REPORTS AND RAP BUFR SOUNDINGS SUPPORT THIS... AS
A WARM LAYER REMAINS PRESENT AROUND 800-850MB. SFC TEMPS REMAIN
WELL ABOVE FREEZING... SO EXPECT NO ISSUES WITH REGARDS TO TRAVEL.
07Z SFC ANALYSIS HAS THE COLD FRONT PUSHING INTO FAR SERN OK...
WITH THE FREEZING LINE NEAR AN ERICK TO WATONGA TO CHEROKEE LINE
IN NWRN OK. GUIDANCE FROM THE HRRR... RAP AND WRF STILL DEVELOP A
LIGHT BAND OF SNOW FROM SWRN OK INTO CENTRAL OK THROUGH SUNRISE.
ANY ACCUMULATIONS WILL BE MINOR... A DUSTING TO A QUARTER OF AN
INCH AS SFC TEMPS WILL REMAIN AT OR JUST ABOVE FREEZING. 2 INCH
SOIL TEMPS FROM THE OKMESONET AT 115 AM ARE STILL IN THE LOW TO
MID 40S. EXPECT MINOR TO NO IMPACT ON TRAFFIC AT THIS TIME.
JTK
&&
.PREV DISCUSSION... /ISSUED 914 PM CST FRI DEC 26 2014/
UPDATE...
MADE MINOR ADJUSTMENTS TO POPS OVERNIGHT AS RADAR TRENDS SUGGEST
CHANCES FOR -SN HAVE DECREASED SOMEWHAT ACROSS FAR NORTHWESTERN
OKLAHOMA. ALSO INTRODUCED ISO THUNDER OVER SOUTH CENTRAL OK WITH
RECENT HEAVY SHOWER DEVELOPMENT. OTHERWISE...THE FORECAST IS
LARGELY UNCHANGED. STILL EXPECT LIGHT SNOW OR A MIX OF RAIN/SNOW
FROM ROUGHLY I-44 WEST THROUGH SATURDAY AM. ACCUMULATIONS IF
ANY...WILL BE QUITE LOW...THOUGH ANY SNOWBANDS THAT DEVELOP MAY
LOCALLY LEAD TO A DUSTING TO QUARTER INCH OF SNOW FROM
NORTHWESTERN THROUGH WEST CENTRAL AND SOUTHWESTERN OKLAHOMA.
IMPACTS SHOULD BE MINOR GIVEN GROUND TEMPS ABOVE FREEZING...BUT
EXPOSED ROADS SUCH AS BRIDGES AND OVERPASSES MAY BECOME SLICK IN A
FEW PLACES THAT SEE LIGHT SNOW ACCUMULATIONS.
PREV DISCUSSION... /ISSUED 520 PM CST FRI DEC 26 2014/
AVIATION...
COLD FRONT NEAR I-44 CORRIDOR WILL CONT TO PUSH SOUTHEAST THIS
EVENING WITH NORTH WINDS THROUGH REMAINDER OF FORECAST. A FEW
GUSTS ACROSS SOUTHWEST SITES MAY EXCEED 20KTS THIS EVENING.
OTHERWISE MVFR CEILINGS EXPECTED TO GIVE WAY TO MAINLY CLEAR
SKIES DURING THE DAY ON SATURDAY... ESPECIALLY BY AFTN. THERE
IS A CHANCE FOR SOME LIGHT SNOW ACROSS NORTHWEST THIS EVENING
AND LIGHT RAIN NEAR I-44 CORRIDOR... HOWEVER CHANCES REMAIN TOO
LOW TO MENTION IN FORECAST AT THIS TIME.
30
PREV DISCUSSION... /ISSUED 321 PM CST FRI DEC 26 2014/
DISCUSSION...
A WAVE IS LIFTING NORTHEAST FROM THE ROCKIES INTO THE CENTRAL
PLAINS TODAY. MUCH OF THE PRECIPITATION THAT IS OBSERVED ON RADAR
IN THE EASTERN TEXAS PANHANDLE IS VIRGA AS LOW LEVELS REMAIN DRY
IN THE SOUTHEASTERN PANHANDLE. THERE IS A BIT MORE LOW LEVEL
MOISTURE IN THE NORTHEASTERN PANHANDLES AND NORTHWESTERN OKLAHOMA
AS EVIDENCED BY THE STRATUS... SO WILL KEEP CHANCE POPS THERE.
WILL ALSO KEEP CHANCE POPS EAST WHERE SOME LIGHT RAIN/DRIZZLE
DEVELOPMENT. BUT OVERALL FOR TONIGHT AND TOMORROW... IT DOES NOT
LOOK LIKE TOO SIGNIFICANT OF AN EVENT OVER THE AREA AND WILL
CONTINUE TO TREND OF DECREASING POPS AND EXPECTED PRECIPITATION
AMOUNTS.
THE OTHER MAIN WEATHER ISSUE IS EXPECTED TO BE THE SIGNIFICANTLY
COLDER WEATHER NEXT WEEK. THE FORECAST STILL LOOKS GOOD WITH THIS
AND DID NOT MAKE ANY SIGNIFICANT CHANGES IN THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 39 25 46 28 / 20 0 0 0
HOBART OK 40 22 46 26 / 10 0 0 0
WICHITA FALLS TX 42 26 48 31 / 20 0 0 0
GAGE OK 37 18 45 20 / 0 0 0 0
PONCA CITY OK 39 22 43 25 / 10 0 0 0
DURANT OK 44 29 47 31 / 30 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/23
AREA FORECAST DISCUSSION
NWS PORTLAND OR
855 PM PST FRI DEC 26 2014
.SYNOPSIS...A FEW SHOWERS WILL CONTINUE NORTH OF THE COLUMBIA RIVER
OVERNIGHT. THEN RAIN AND MODERATE TO HEAVY MOUNTAIN SNOW WILL SPREAD
INTO SOUTHWEST WASHINGTON AND FAR NORTHWEST OREGON LATE TONIGHT AND
ACROSS THE AREA SATURDAY AS A COOL SYSTEM DROPS IN FROM THE
NORTHWEST. A TRAILING SECONDARY WAVE WILL MAINTAIN SHOWERS SUNDAY
INTO MONDAY. COLDER AND DRIER WEATHER WITH OFFSHORE WINDS WILL BEGIN
TO FILTER IN ON MONDAY AND KICK IN IN EARNEST MONDAY NIGHT AND
TUESDAY...CONTINUING THROUGH AT LEAST THE MID WEEK PERIOD. THE NEXT
CHANCE OF SOME PRECIPITATION MAY BE LATE IN THE WEEK OR NEXT
WEEKEND.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...A FEW SHOWERS CONTINUE TO
LINGER THIS EVENING ALONG THE NORTH COASTAL AREAS AND INTO THE SOUTH
WASHINGTON CASCADES...THOUGH THEY HAVE DECREASED SOME FROM EARLIER
THIS EVENING. ATTENTION THEN TURNS TO THE SYSTEM DROPPING SOUTH
THROUGH B.C. THIS EVENING. THIS COOL SYSTEM WILL START TO SPREAD SOME
RAIN AND MOUNTAIN SNOW INTO OUR FAR NORTH ZONES AFTER MIDNIGHT
TONIGHT...THEN SPREAD ACROSS THE ENTIRE AREA DURING THE DAY ON
SATURDAY. THERE IS A DECENT 100 KT UPPER JET WITH IT AND AMPLE
ONSHORE FLOW...SO WE SHOULD SEE ANOTHER ROUND OF DECENT SNOWS IN THE
CASCADES. WILL CONTINUE THE SNOW ADVISORIES.
THE FIRST MAIN FRONT MOVES THROUGH SATURDAY AFTERNOON AND EVENING...
BUT THEN THE MODELS SHOW CONTINUING ONSHORE FLOW AND ANOTHER SHORT
WAVE LATER SUNDAY INTO MONDAY FOR MORE VALLEY RAIN SHOWERS AND
MOUNTAINS SNOW. THE HEAVIEST SNOWFALL RATES LOOK TO BE SATURDAY AND
SATURDAY NIGHT WITH AMOUNTS RANGING FROM 8 TO 14 INCHES NORTH TO 4
TO 8 INCHES SOUTH...BUT WE SHOULD STILL GET SOME ACCUMULATING SNOW
IN THE CASCADES ON SUNDAY INTO SUNDAY NIGHT THAT MAY STILL IMPACT
TRAFFIC. AMOUNTS WILL BE MORE IN THE 1 TO 3 TO 2 TO 4 INCH RANGE
SUNDAY AND POSSIBLY AGAIN SUNDAY NIGHT. HAVE UPPED POPS SOME THOSE 2
FORECAST PERIODS.
THE PRECIPITATION WILL BE DECREASING FROM THE NORTH MONDAY AS DRIER
AND COLDER AIR STARTS TO FILTER IN...AND SOME EAST WINDS START TO
DEVELOP IN THE GORGE. THE MAIN PERIOD OF STRONGER EAST WIND WILL
DEVELOP MONDAY NIGHT AND CONTINUE THROUGH THE MID WEEK PERIOD...
USHERING IN MUCH COLDER WEATHER ACROSS THE FORECAST AREA. TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MONDAY NIGHT THROUGH THURSDAY NIGHT...A PERSISTENT WEATHER PATTERN
WILL SET UP EARLY NEXT WEEK AS A REX BLOCK DEVELOPS WITH STRONG HIGH
PRESSURE ALOFT OVER THE PACIFIC NW AND AN UPPER LOW OVER THE CA/AZ.
TEMPERATURES ARE EXPECTED TO DRAMATICALLY DROP MONDAY NIGHT WITH LOWS
AROUND 30 FOR THE COAST...LOW TO MID 20S FOR THE INTERIOR
VALLEYS...AND BELOW 20 FOR THE CASCADES AND CASCADE FOOTHILLS.
DAYTIME HIGHS BEGINNING TUESDAY WILL REMAIN NEAR OR BELOW FREEZING
FOR MANY LOCATIONS...WITH THE EXCEPTION OF THE COAST BEING SLIGHTLY
WARMER. THESE COLD TEMPERATURES ALONG WITH NORTHEAST WINDS WILL
PERSIST THROUGH WEDNESDAY. THE MODELS ARE SHOWING THE BLOCKING
PATTERN DISINTEGRATING THU...ENDING THE OFFSHORE WINDS AND ALLOWING
TEMPERATURES TO RECOVER A LITTLE BIT BY FRIDAY. MODELS TEND TO BREAK
DOWN THESE BLOCKS TOO EARLY AND THERE IS A CHANCE THAT THE VERY COLD
CONDITIONS WILL PERSIST A DAY OR TWO LONGER. BOWEN/TJ
&&
.AVIATION... OVERALL GENERAL IMPROVEMENT IN FLIGHT CONDITIONS THIS
EVENING. NEARLY ALL METAR SITES ARE VFR AS OF 04Z. THE EXCEPTION IS
THE EXTREME N OREGON AND S WA COAST WHERE IFR EXISTS. EXPECT A RETURN
TO MAINLY MVFR CIGS OVERNIGHT...WITH LOCALIZED IFR CONDITIONS IN THE
INTERIOR VALLEYS. NOT LOOKING FOR ANY EXTENDED CLEARING PERIODS
OVERNIGHT THUS LIFR NOT EXPECTED. LATEST NAM AND HRRR MODELS SHOW THE
LEADING EDGE OF THE PRECIP SHIELD REACHING THE S WA AND N OREGON
COAST AROUND 12-14Z. WILL GO WITH IFR TO MVFR AT KAST STARTING AROUND
THAT TIME. PRECIP SPREADS SE SAT MORNING WITH INCREASING MVFR. THERE
MAY BE SOME AREAS OF IFR WITH THE INITIAL PRECIP DUE TO LIMITED WIND.
HOWEVER...SURFACE GRADIENTS PICK UP DURING THE MORNING...WHICH SHOULD
PRODUCE ENOUGH MIXING IN THE INTERIOR VALLEYS TO ELIMINATE IFR.
HIGHER TERRAIN BECOMES OBSCURED SAT AFTERNOON THROUGH THE EVENING AS
850 MB WLY WIND INCREASES.
KPDX AND APPROACHES...CONDITIONS HAVE IMPROVED TO VFR THIS EVENING
BUT STILL EXPECT A RETURN TO PREDOMINANT MVFR OVERNIGHT. INITIAL
PRECIP LOOKS TO REACH THE TERMINAL AND VICINITY 14-16Z SAT. THERE IS
THE POSSIBILITY OF IFR WITH THE INITIAL PRECIP DUE TO WEAK SURFACE
GRADIENTS. HOWEVER...SURFACE WIND SHOULD PICK UP MID TO LATE MORNING
RESULTING MVFR TO LOW-END VFR CONDITIONS THRU THE AFTERNOON AND
EVENING HOURS. WEISHAAR
&&
.MARINE...HIGH PRESSURE OVER THE WATERS WILL WEAKEN OVERNIGHT AS THE
NEXT FRONTAL SYSTEM DROPS S ALONG THE BRITISH COLUMBIA COAST. LATEST
NAM RUN PRETTY CONSISTENT WITH ITS PREVIOUS VERSION SHOWING 20 TO 25
KT WIND DEVELOPING OVER THE FAR NRN WATERS AROUND 20Z SAT. THE WIND
GRADUALLY INCREASES OVER ALL WATERS SAT AFTERNOON AND EVENING...WITH
LOCALIZED GUSTS TO 35 KT POSSIBLE OVER THE NRN WATERS 00Z SUN THROUGH
AT LEAST 12Z SUN. HAVE OPTED TO GO WITH SEPARATE SMALL CRAFT
ADVISORIES FOR WIND...STARTING IN THE NRN WATERS 20Z SAT BUT HOLDING
OFF IN THE SRN WATERS UNTIL 23Z. ALSO ENDED THE ADVISORY A BIT SOONER
IN THE SRN WATERS. THE NWLY WIND GRADUALLY WEAKENS SUN EVENING AND
SUN NIGHT. MODELS ARE IN GOOD AGREEMENT ON THE TRANSITION TO
OFF-SHORE WIND BEGINNING MON AFTERNOON. WILL NEED TO WATCH FOR SMALL
CRAFT ADVISORY WIND MON NIGHT THROUGH AT LEAST MID-WEEK.
SEAS TO RAMP UP AGAIN WITH THE NEXT FRONTAL SYSTEM. THERE MAY BE A
DYNAMIC FETCH SET UP WITH THIS NEXT ONE...WHICH MEANS THE WAVE
GUIDANCE MAY BE A LITTLE UNDERDONE WITH THE OVERALL WAVE HEIGHTS.
SEAS SHOULD PEAK IN THE 14-17 FT RANGE IN THE NRN WATERS LATE SAT
NIGHT OR SUN MORNING. THIS DOES NOT LOOK LIKE A LONG-DURATION FETCH
SITUATION SO THE TIME FRAME FOR MAX SEAS SHOULD BE ON THE ORDER OF 5
TO 10 HOURS. SEAS FALL BELOW 10 FT LATE SUN NIGHT OR MON MORNING AND
REMAIN WELL BELOW 10 FT FOR MUCH OF THE WEEK. WEISHAAR
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY FROM 10 AM SATURDAY TO 10 AM PST SUNDAY
FOR CASCADES IN LANE COUNTY-NORTHERN OREGON CASCADES.
WA...WINTER WEATHER ADVISORY FROM 4 AM SATURDAY TO 4 AM PST SUNDAY
FOR SOUTH WASHINGTON CASCADES.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM NOON SATURDAY TO 10 PM PST
SUNDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE
HEAD OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM SATURDAY TO 9
AM PST MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR WINDS FROM 3 PM SATURDAY TO 6 PM PST
SUNDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR
OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST THIS EVENING.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM TO
10 PM PST SATURDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
534 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 515 PM...LIGHT AND HIGH RADAR RETURNS WERE TRACKING ACROSS NRN
GA. THESE RETURNS HAVE NOT BEEN ASSOCIATED WITH SFC OBS OF
RAIN...EXPECTING RETURNS FROM VIRGA. HOWEVER...A LARGE PATCH OF
LIGHT RAIN WAS DRIFTING ACROSS THE AL/GA LINE...THIS AREA SHOULD
RESULT IN RAIN ACROSS THE CWA LATER TONIGHT. I WILL UPDATE TO ADJUST
POP TIMING AND ALIGN TEMP/DWPT WITH OBSERVATIONS.
AS OF 240 PM EST SATURDAY...THE LATEST SATELLITE IMAGE SHOWS A DEEP
AND MOIST WARM CONVEYOR BELT EXTENDING FROM THE GREAT LAKES REGION
DOWN TO THE WESTERN GULF...AND TO THE EASTERN PACIFIC...WITH BROAD
AREAS OF CONVECTION DEVELOPING ACROSS THE DEEP SOUTH AS OF THIS
AFTERNOON HOURS. AS AN EASTERN CONUS UPPER RIDGE AXIS PUSHES OFF THE
ATLANTIC COAST AND MOIST SWLY FLOW ALOFT SETS UP OVER THE SOUTHEAST
US...MID TO LOW LEVEL CLOUDS WILL SPREAD OVER THE PIEDMONT THROUGH
THE AFTERNOON HOURS.THE LATEST SHORT TERM MODELS CONTINUE TO
INDICATE THAT A COLD FRONT WILL SLOWLY MOVE EAST ACROSS THE
MISSISSIPPI VALLEY AND INTO THE TN VALLEY TONIGHT INTO SUN
MORNING...REACHING THE SOUTHERN APPALACHIANS BY SUN AFTERNOON. AHEAD
OF THIS FRONT...A DEEP PLUME OF GULF MOISTURE WILL BE DRAWN UP INTO
THE REGION AS A WAVE OF LOW OVER THE WESTERN GULF LIFTS NE ACROSS
AL/MI TONIGHT. THEREFORE...POPS QUICKLY RAMP UP FROM WEST TO EAST
INTO THE CATEGORICAL RANGE OVER THE WESTERN MTNS ZONES AND NE
GA...WITH LIKELY RANGE OVER THE REST OF THE WESTERN HALF OF THE CWA.
THE BEST RAINFALL RATES WILL OCCUR BETWEEN 12Z-18Z SUN WHEN THE
SURFACE WAVE OF LOW LIFTS NE ACROSS THE CWA AND A SERIES OF UPPER
DISTURBANCES RIPPLES ACROSS THE MTNS ZONES IN SWLY FLOW ALOFT.
ALSO...HAVE MENTIONED A CHANCE OF THUNDER ACROSS MUCH OF THE REGION
EARLY SUN AFTERNOON DUE TO THE PRESENCE OF 100-200J/KG MUCAPE PER
LATEST NAM/GFS/ECMWF. POPS RAMP DOWN TO THE LIKELY RANGE OVER THE
MTN ZONES AND SOLD CHANCE RANGE OVER THE SOUTHERN TIER OF THE REGION
18Z THRU 00Z MON AS THE UPPER FORCING AND THE SURFACE WAVE OF LOW
MOVES OFF TO THE NE. WITH MODELS TRENDING A BIT WETTER FOR THE
UPCOMING EVENT...HAVE GONE WITH THE HPC QPF GUIDANCE RESULTING IN
0.75-1.0" OVER THE WESTERN NC MTNS AND NE GA... WITH AROUND
0.25-0.5" ELSEWEHRE THRU SUN EVENINING.
WITH CONSIDERABLE CLOUD COVER AND WAA SOUTHERLY FLOW...OVERNIGHT
TEMPS WILL STAY 7-10 DEGREES ABOVE NORMAL. WITH ONGOING
PRECIP...AFTERNOON HIGHS ON SUN WILL BE AROUND 3-5 DEGREES COOLER
THAN TODAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 200 PM SATURDAY...THE MODELS SUGGEST THAT WE WILL BE IN A LULL
OF SORTS AT THE START OF THE SHORT RANGE PERIOD SUNDAY EVENING...AS
WE WILL BE IN A MINIMUM OF FORCING. THAT CHANGES QUICKLY BY LATE
EVENING AS THE RIGHT ENTRANCE REGION OF THE UPPER JET TRANSLATES
OVERHEAD BETWEEN ROUGHLY 03Z AND 09Z...AND THE MAIN SHORT WAVE AXIS
MOVES THROUGH IN THE 06Z TO 12Z MONDAY TIME FRAME. ALTHO THE WAVE
SHEARS AND DEAMPLIFIES AS IT CROSSES THE REGION...THE FORCING SHOULD
STILL BE SUFFICIENT TO INCREASE PRECIP PRODUCTION...COMBINED WITH
IMPROVED MOIST ISENTROPIC LIFT. SO...PRECIP CHANCES RAMP BACK UP TO
CATEGORICAL MAINLY OVER THE AREA ALONG AND N/W OF I-85...AND LIKELY
TO THE S...BY 06Z OR SO. THE MAIN FORCING SHOULD SHIFT E OF THE AREA
MONDAY MORNING. THE HIGHEST PRECIP PROBABILITY WILL BE OVER THE WRN
NC PIEDMONT ON MONDAY MORNING. POP WAS LIMITED TO LIKELY OUT OF
UNCERTAINTY WITH TIMING THE DEPARTURE OF THE FORCING...BUT COULD
EASILY HAVE TO BE KEPT CATEGORICAL BEYOND 12Z MONDAY WITH THE
SLIGHTEST DELAY. THE REST OF MONDAY WILL HAVE A SLOW RAMP DOWN
THROUGH THE CHANCE RANGE AS FORCING GRADUALLY WEAKENS BEHIND THE
SURFACE FRONT THAT CROSSES FIRST THING IN THE DAY. FOR MONDAY NIGHT
AND TUESDAY...THERE IS UNCERTAINTY REGARDING THE EXTENT/CHANCE OF
PRECIP. THE LOW LEVEL FLOW COMES AROUND TO SOMETHING NW MONDAY NIGHT
AND TUESDAY WHICH SHOULD FORCE SOME SHOWER ACTIVITY NEAR THE TN
BORDER. THE PASSAGE OF ANOTHER SHORT WAVE COMBINED WITH SOME LOW
LEVEL FRONTOGENESIS APPEARS TO BE RESPONSIBLE FOR THE REDEVELOPMENT
OF PRECIP ON TUESDAY OFF TO OUR N...WHICH SOME OF THE GUIDANCE
BLEEDS DOWN INTO NC. PREFER TO KEEP THE BETTER CHANCES IN THE
UPSLOPE AREAS OF THE NRN MTNS AND TO KEEP THE AREA E OF THE BLUE
RIDGE DRY FOR THE TIME BEING. TEMPS SHOULD DROP BACK DOWN TO NEAR
NORMAL ON TUESDAY.
ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE
UP THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER
THE BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE
WOULD LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION
AHEAD OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE
POOR AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS.
OVERALL THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE
TO NO INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO
PROGRESS EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM
TROUGH IS HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL
NOT ACTUALLY ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT
500MB SHORTWAVE ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC
WITH RR QUAD OF A JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...THE MEDIUM RANGE WILL START OUT WITH SPLIT
UPPER LVL FLOW...WITH A LARGE POLAR VORTEX SPINNING OVR HUDSON
BAY...AND A CUTOFF LOW INVOF CALIFORNIA. THE MODEL GUIDANCE HAS BEEN
SLOWLY CONVERGING ON THE TIMING OF THE CUTOFF LOW BEING EJECT ACRS
INTO THE SOUTHERN STREAM AROUND FRIDAY. HOWEVER...THERE IS STILL
SOME DISAGREEMENT ON THAT...WITH THE GFS CONSISTENTLY
FASTER/EARLIER...AND THE ECMWF SLOWER/DEEPER. THE LATEST WPC
PREFERENCE IS WITH THE ENSEMBLE MEAN...SLOWER THAN THE GFS...AND NOT
AS DEEP WITH THE RESULTED PROGRESSIVE SHORTWAVE TROF AS THE ECMWF.
AT THE SFC...A BROAD AREA OF CANADIAN HIGH PRES WILL ENCOMPASS ABOUT
3/4TH OF THE CONUS ON WEDNESDAY...GRADUALLY MODIFYING AND DRIFTING
EAST WITH THE CENTER CROSSING THE CWFA EARLY FRIDAY. DRY WEATHER AND
SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED WEDNESDAY THRU THURSDAY
NIGHT. AS THE EJECTING UPPER TROF FINALLY ENTERS THE SOUTHERN
PLAINS...A LOW PRES SYSTEM SHUD BEGIN TO ORGANIZE...TAPPING INTO
COPIOUS GULF MOISTURE. POPS WILL THEN RAMP UP BY NEXT WEEKEND. OF
COURSE...EXACT TIMING IS STILL THE MAIN QUESTION. THE 12Z GFS AND
ECMWF BOTH SHOW POSSIBLE WINTRY MIX PRECIP TYPE CONCERNS AT ONSET
FRIDAY MORNING...BUT THEN TURNING OVER TO ALL RAIN...AS STRONG SWLY
WAA SHUD DOMINATE ANY LINGERING IN SITU COLD AIR DAMMING.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE AT LEAST THRU
TONIGHT. CONSIDERABLE CLOUDINESS WILL SPREAD IN FROM THE WEST THIS
AFTERNOON THROUGH TONIGHT AS MOIST SWLY FLOW ALOFT DEVELOPS. AS
DEEPER GULF MOISTURE ASSOCIATED WITH A WAVE OF LOW APPROACHES FROM
THE SW...MVFR CLOUDS WITH PRECIP WILL SPREAD ACROSS THE AREA FROM
WEST TO EAST LATE TONIGHT THRU EARLY SUN MORNING. LATEST GUIDANCE IS
SUPPORTIVE OF IFR VSBY/CIGS WITH ONGOING SHRA THRU 18Z SUN...AS A
WAVE OF LOW PASSES JUST TO OUR NORTH. THERE APPEARS TO BE A CHANCE
OF THUNDER AS MODEL SOUNDINGS DEPICT WEAK ELEVATED INSTABILITY ON
SUN AFTERNOON. DUE TO THE UNCERTAINTY...THUNDER WAS NOT CARRIED IN
THE TAF. LIGHT SW WINDS SHOULD PREVAIL THRU THE PERIOD...EXCEPT KAVL
WHERE S WINDS WILL VEER TO THE NORTH BY SUN AFTERNOON.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
22-04Z 04-10Z 10-16Z 16-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% MED 66% HIGH 91%
KAVL HIGH 100% HIGH 100% MED 66% HIGH 87%
KHKY HIGH 100% HIGH 100% HIGH 87% HIGH 93%
KGMU HIGH 100% HIGH 100% MED 66% HIGH 100%
KAND HIGH 100% HIGH 100% MED 66% HIGH 87%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...NED
SHORT TERM...PM
LONG TERM...ARK
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
306 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 240 PM EST SATURDAY...THE LATEST SATELLITE IMAGE SHOWS A DEEP
AND MOIST WARM CONVEYOR BELT EXTENDING FROM THE GREAT LAKES REGION
DOWN TO THE WESTERN GULF...AND TO THE EASTERN PACIFIC...WITH BROAD
AREAS OF CONVECTION DEVELOPING ACROSS THE DEEP SOUTH AS OF THIS
AFTERNOON HOURS. AS AN EASTERN CONUS UPPER RIDGE AXIS PUSHES OFF THE
ATLANTIC COAST AND MOIST SWLY FLOW ALOFT SETS UP OVER THE SOUTHEAST
US...MID TO LOW LEVEL CLOUDS WILL SPREAD OVER THE PIEDMONT THROUGH
THE AFTERNOON HOURS.THE LATEST SHORT TERM MODELS CONTINUE TO
INDICATE THAT A COLD FRONT WILL SLOWLY MOVE EAST ACROSS THE
MISSISSIPPI VALLEY AND INTO THE TN VALLEY TONIGHT INTO SUN
MORNING...REACHING THE SOUTHERN APPALACHIANS BY SUN AFTERNOON. AHEAD
OF THIS FRONT...A DEEP PLUME OF GULF MOISTURE WILL BE DRAWN UP INTO
THE REGION AS A WAVE OF LOW OVER THE WESTERN GULF LIFTS NE ACROSS
AL/MI TONIGHT. THEREFORE...POPS QUICKLY RAMP UP FROM WEST TO EAST
INTO THE CATEGORICAL RANGE OVER THE WESTERN MTNS ZONES AND NE
GA...WITH LIKELY RANGE OVER THE REST OF THE WESTERN HALF OF THE CWA.
THE BEST RAINFALL RATES WILL OCCUR BETWEEN 12Z-18Z SUN WHEN THE
SURFACE WAVE OF LOW LIFTS NE ACROSS THE CWA AND A SERIES OF UPPER
DISTURBANCES RIPPLES ACROSS THE MTNS ZONES IN SWLY FLOW ALOFT.
ALSO...HAVE MENTIONED A CHANCE OF THUNDER ACROSS MUCH OF THE REGION
EARLY SUN AFTERNOON DUE TO THE PRESENCE OF 100-200J/KG MUCAPE PER
LATEST NAM/GFS/ECMWF. POPS RAMP DOWN TO THE LIKELY RANGE OVER THE
MTN ZONES AND SOLD CHANCE RANGE OVER THE SOUTHERN TIER OF THE REGION
18Z THRU 00Z MON AS THE UPPER FORCING AND THE SURFACE WAVE OF LOW
MOVES OFF TO THE NE. WITH MODELS TRENDING A BIT WETTER FOR THE
UPCOMING EVENT...HAVE GONE WITH THE HPC QPF GUIDANCE RESULTING IN
0.75-1.0" OVER THE WESTERN NC MTNS AND NE GA... WITH AROUND
0.25-0.5" ELSEWEHRE THRU SUN EVENINING.
WITH CONSIDERABLE CLOUD COVER AND WAA SOUTHERLY FLOW...OVERNIGHT
TEMPS WILL STAY 7-10 DEGREES ABOVE NORMAL. WITH ONGOING
PRECIP...AFTERNOON HIGHS ON SUN WILL BE AROUND 3-5 DEGREES COOLER
THAN TODAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 200 PM SATURDAY...THE MODELS SUGGEST THAT WE WILL BE IN A LULL
OF SORTS AT THE START OF THE SHORT RANGE PERIOD SUNDAY EVENING...AS
WE WILL BE IN A MINIMUM OF FORCING. THAT CHANGES QUICKLY BY LATE
EVENING AS THE RIGHT ENTRANCE REGION OF THE UPPER JET TRANSLATES
OVERHEAD BETWEEN ROUGHLY 03Z AND 09Z...AND THE MAIN SHORT WAVE AXIS
MOVES THROUGH IN THE 06Z TO 12Z MONDAY TIME FRAME. ALTHO THE WAVE
SHEARS AND DEAMPLIFIES AS IT CROSSES THE REGION...THE FORCING SHOULD
STILL BE SUFFICIENT TO INCREASE PRECIP PRODUCTION...COMBINED WITH
IMPROVED MOIST ISENTROPIC LIFT. SO...PRECIP CHANCES RAMP BACK UP TO
CATEGORICAL MAINLY OVER THE AREA ALONG AND N/W OF I-85...AND LIKELY
TO THE S...BY 06Z OR SO. THE MAIN FORCING SHOULD SHIFT E OF THE AREA
MONDAY MORNING. THE HIGHEST PRECIP PROBABILITY WILL BE OVER THE WRN
NC PIEDMONT ON MONDAY MORNING. POP WAS LIMITED TO LIKELY OUT OF
UNCERTAINTY WITH TIMING THE DEPARTURE OF THE FORCING...BUT COULD
EASILY HAVE TO BE KEPT CATEGORICAL BEYOND 12Z MONDAY WITH THE
SLIGHTEST DELAY. THE REST OF MONDAY WILL HAVE A SLOW RAMP DOWN
THROUGH THE CHANCE RANGE AS FORCING GRADUALLY WEAKENS BEHIND THE
SURFACE FRONT THAT CROSSES FIRST THING IN THE DAY. FOR MONDAY NIGHT
AND TUESDAY...THERE IS UNCERTAINTY REGARDING THE EXTENT/CHANCE OF
PRECIP. THE LOW LEVEL FLOW COMES AROUND TO SOMETHING NW MONDAY NIGHT
AND TUESDAY WHICH SHOULD FORCE SOME SHOWER ACTIVITY NEAR THE TN
BORDER. THE PASSAGE OF ANOTHER SHORT WAVE COMBINED WITH SOME LOW
LEVEL FRONTOGENESIS APPEARS TO BE RESPONSIBLE FOR THE REDEVELOPMENT
OF PRECIP ON TUESDAY OFF TO OUR N...WHICH SOME OF THE GUIDANCE
BLEEDS DOWN INTO NC. PREFER TO KEEP THE BETTER CHANCES IN THE
UPSLOPE AREAS OF THE NRN MTNS AND TO KEEP THE AREA E OF THE BLUE
RIDGE DRY FOR THE TIME BEING. TEMPS SHOULD DROP BACK DOWN TO NEAR
NORMAL ON TUESDAY.
ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE
UP THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER
THE BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE
WOULD LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION
AHEAD OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE
POOR AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS.
OVERALL THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE
TO NO INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO
PROGRESS EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM
TROUGH IS HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL
NOT ACTUALLY ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT
500MB SHORTWAVE ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC
WITH RR QUAD OF A JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...THE MEDIUM RANGE WILL START OUT WITH SPLIT
UPPER LVL FLOW...WITH A LARGE POLAR VORTEX SPINNING OVR HUDSON
BAY...AND A CUTOFF LOW INVOF CALIFORNIA. THE MODEL GUIDANCE HAS BEEN
SLOWLY CONVERGING ON THE TIMING OF THE CUTOFF LOW BEING EJECT ACRS
INTO THE SOUTHERN STREAM AROUND FRIDAY. HOWEVER...THERE IS STILL
SOME DISAGREEMENT ON THAT...WITH THE GFS CONSISTENTLY
FASTER/EARLIER...AND THE ECMWF SLOWER/DEEPER. THE LATEST WPC
PREFERENCE IS WITH THE ENSEMBLE MEAN...SLOWER THAN THE GFS...AND NOT
AS DEEP WITH THE RESULTED PROGRESSIVE SHORTWAVE TROF AS THE ECMWF.
AT THE SFC...A BROAD AREA OF CANADIAN HIGH PRES WILL ENCOMPASS ABOUT
3/4TH OF THE CONUS ON WEDNESDAY...GRADUALLY MODIFYING AND DRIFTING
EAST WITH THE CENTER CROSSING THE CWFA EARLY FRIDAY. DRY WEATHER AND
SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED WEDNESDAY THRU THURSDAY
NIGHT. AS THE EJECTING UPPER TROF FINALLY ENTERS THE SOUTHERN
PLAINS...A LOW PRES SYSTEM SHUD BEGIN TO ORGANIZE...TAPPING INTO
COPIOUS GULF MOISTURE. POPS WILL THEN RAMP UP BY NEXT WEEKEND. OF
COURSE...EXACT TIMING IS STILL THE MAIN QUESTION. THE 12Z GFS AND
ECMWF BOTH SHOW POSSIBLE WINTRY MIX PRECIP TYPE CONCERNS AT ONSET
FRIDAY MORNING...BUT THEN TURNING OVER TO ALL RAIN...AS STRONG SWLY
WAA SHUD DOMINATE ANY LINGERING IN SITU COLD AIR DAMMING.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE AT LEAST THRU
TONIGHT. CONSIDERABLE CLOUDINESS WILL SPREAD IN FROM THE WEST THIS
AFTERNOON THROUGH TONIGHT AS MOIST SWLY FLOW ALOFT DEVELOPS. AS
DEEPER GULF MOISTURE ASSOCIATED WITH A WAVE OF LOW APPROACHES FROM
THE SW...MVFR CLOUDS WITH PRECIP WILL SPREAD ACROSS THE AREA FROM
WEST TO EAST LATE TONIGHT THRU EARLY SUN MORNING. LATEST GUIDANCE IS
SUPPORTIVE OF IFR VSBY/CIGS WITH ONGOING SHRA THRU 18Z SUN...AS A
WAVE OF LOW PASSES JUST TO OUR NORTH. THERE APPEARS TO BE A CHANCE
OF THUNDER AS MODEL SOUNDINGS DEPICT WEAK ELEVATED INSTABILITY ON
SUN AFTERNOON. DUE TO THE UNCERTAINTY...THUNDER WAS NOT CARRIED IN
THE TAF. LIGHT SW WINDS SHOULD PREVAIL THRU THE PERIOD...EXCEPT KAVL
WHERE S WINDS WILL VEER TO THE NORTH BY SUN AFTERNOON.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 95%
KGSP HIGH 100% HIGH 100% MED 77% HIGH 83%
KAVL HIGH 100% HIGH 100% MED 64% MED 77%
KHKY HIGH 100% HIGH 100% HIGH 93% HIGH 82%
KGMU HIGH 100% HIGH 100% MED 74% HIGH 85%
KAND HIGH 100% HIGH 100% MED 72% HIGH 80%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JOH
SHORT TERM...PM
LONG TERM...ARK
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1246 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
1145 AM EST UPDATE...LATEST RADAR TREND SHOWS AREAS OF LIGHT PRECIP
CURRENTLY OVER THE NORTH-CENTRAL GA LIFTING NORTHEAST TOWARDS NE GA
AND SW MTNS ZONES AS OF LATE MORNING HOURS. LATEST MESO-SCALE MODELS
INCLUDING THE RAP AND HRRR SUGGEST THAT THE AFOREMENTIONED FEATURE
WILL REACH THE NE GA AND SW MTN ZONES BY AROUND 18Z AND DRIES OUT
TOWARD 21Z. HENCE...HAVE KEPT THE LOW-END CHANCE POPS OVER THE
EXTREME WESTERN TIER OF THE CWA...BEFORE RAMPING DOWN TO THE SLIGHT
CHANCE RANGE BY 21Z. POPS THEN RAMP UP FROM WEST TO EAST THROUGH
TONIGHT AS DEEPER GULF MOISTURE ARRIVES. AS FOR THE PRECIP
TYPE...HAVE MENTIONED SHOWERS THROUGH SUNDAY... WITH CHANCE OF
THUNDER...OVER THE WESTERN PORTIONS OF THE CWA AS MODELS SUGGEST
THAT SOME DEGREE OF ELEVATED INSTABILITY (100-200J/KG MUCAPE)WILL BE
PRESENT ON SUN AFTERNOON. HAVE RAISED THE QPF THRU SUN AFTERNOON PER
LATEST GUIDANCE.
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOW AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND THE EXTREME WESTERN NC MTNS AS OF
THIS MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE
ACROSS THE WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP
CURRENTLY OVER AL AND PORTIONS OF NW GA WILL MOVE
EASTWARD...REACHING NE GA AND SW MTNS BY AROUND 18Z TODAY.
HOWEVER...LATEST HRRR SUGGESTS THIS FEATURE WILL WEAKEN AS IT ENTERS
OUR CWA ATT. HENCE...SLIGHT CHANCE TO THE LOW END CHANCE POPS WERE
WARRANTED THERE THROUGH THE MORNING HOURS INTO EARLY PART OF THIS
AFTERNOON. WITH TEMPS WARMING UP ABOVE THE FREEZING LEVEL...SHRA WAS
MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE AT LEAST THRU
TONIGHT. CONSIDERABLE CLOUDINESS WILL SPREAD IN FROM THE WEST THIS
AFTERNOON THRU THRU TONIGHT AS MOIST SWLY FLOW ALOFT DEVELOPS. AS
DEEPER GULF MOISTURE ASSOCIATED WITH A WAVE OF LOW APPROACHES FROM
THE SW...MVFR CLOUDS WITH PRECIP WILL SPREAD ACROSS THE AREA FROM
WEST TO EAST LATE TONIGHT THRU EARLY SUN MORNING. LATEST GUIDANCE IS
SUPPORTIVE OF IFR VSBY/CIGS WITH ONGOING SHRA THRU 18Z SUN...AS A
WAVE OF LOW PASSES JUST TO OUR NORTH. LIGHT SW WINDS SHOULD PREVAIL
THRU THE PERIOD...EXECPT KAVL WHERE S WINDS WILL VEER TO THE NORTH
BY SUN AFTERNOON.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% LOW 53%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 70%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KGMU HIGH 100% HIGH 100% HIGH 100% MED 70%
KAND HIGH 100% HIGH 100% HIGH 100% MED 70%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1208 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
1145 AM EST UPDATE...LATEST RADAR TREND SHOWS AREAS OF LIGHT PRECIP
CURRENTLY OVER THE NORTH-CENTRAL GA LIFTING NORTHEAST TOWARDS NE GA
AND SW MTNS ZONES AS OF LATE MORNING HOURS. LATEST MESO-SCALE MODELS
INCLUDING THE RAP AND HRRR SUGGEST THAT THE AFOREMENTIONED FEATURE
WILL REACH THE NE GA AND SW MTN ZONES BY AROUND 18Z AND DRIES OUT
TOWARD 21Z. HENCE...HAVE KEPT THE LOW-END CHANCE POPS OVER THE
EXTREME WESTERN TIER OF THE CWA...BEFORE RAMPING DOWN TO THE SLIGHT
CHANCE RANGE BY 21Z. POPS THEN RAMP UP FROM WEST TO EAST THROUGH
TONIGHT AS DEEPER GULF MOISTURE ARRIVES. AS FOR THE PRECIP
TYPE...HAVE MENTIONED SHOWERS THROUGH SUNDAY... WITH CHANCE OF
THUNDER...OVER THE WESTERN PORTIONS OF THE CWA AS MODELS SUGGEST
THAT SOME DEGREE OF ELEVATED INSTABILITY (100-200J/KG MUCAPE)WILL BE
PRESENT ON SUN AFTERNOON. HAVE RAISED THE QPF THRU SUN AFTERNOON PER
LATEST GUIDANCE.
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOW AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND THE EXTREME WESTERN NC MTNS AS OF
THIS MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE
ACROSS THE WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP
CURRENTLY OVER AL AND PORTIONS OF NW GA WILL MOVE
EASTWARD...REACHING NE GA AND SW MTNS BY AROUND 18Z TODAY.
HOWEVER...LATEST HRRR SUGGESTS THIS FEATURE WILL WEAKEN AS IT ENTERS
OUR CWA ATT. HENCE...SLIGHT CHANCE TO THE LOW END CHANCE POPS WERE
WARRANTED THERE THROUGH THE MORNING HOURS INTO EARLY PART OF THIS
AFTERNOON. WITH TEMPS WARMING UP ABOVE THE FREEZING LEVEL...SHRA WAS
MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% LOW 53%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 70%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KGMU HIGH 100% HIGH 100% HIGH 100% MED 70%
KAND HIGH 100% HIGH 100% HIGH 100% MED 70%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
850 AM EST SAT DEC 27 2014
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. EXPECT TEMPERATURES TO BE A FEW DEGREES
ABOVE NORMAL THIS WEEKEND. THE FRONT WILL CROSS MONDAY WITH A
SECONDARY FRONT PASSING IN MID WEEK DROPPING TEMPERATURES TO BELOW
NORMAL. THE NEXT COLD FRONT WILL ARRIVE AT THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOW AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND THE EXTREME WESTERN NC MTNS AS OF
THIS MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE
ACROSS THE WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP
CURRENTLY OVER AL AND PORTIONS OF NW GA WILL MOVE
EASTWARD...REACHING NE GA AND SW MTNS BY AROUND 18Z TODAY.
HOWEVER...LATEST HRRR SUGGESTS THIS FEATURE WILL WEAKEN AS IT ENTERS
OUR CWA ATT. HENCE...SLIGHT CHANCE TO THE LOW END CHANCE POPS WERE
WARRANTED THERE THROUGH THE MORNING HOURS INTO EARLY PART OF THIS
AFTERNOON. WITH TEMPS WARMING UP ABOVE THE FREEZING LEVEL...SHRA WAS
MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 73%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% MED 64%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
845 AM EST SAT DEC 27 2014
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. EXPECT TEMPERATURES TO BE A FEW DEGREES
ABOVE NORMAL THIS WEEKEND. THE FRONT WILL CROSS MONDAY WITH A
SECONDARY FRONT PASSING IN MID WEEK DROPPING TEMPERATURES TO BELOW
NORMAL. THE NEXT COLD FRONT WILL ARRIVE AT THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOWING AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND SW NC MTNS AS OF THIS
MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE ACROSS THE
WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP CURRENTLY
OVER AL AND PORTIONS OF NW GA WILL MOVE EASTWARD...REACHING NE GA
AND SW MTNS BY AROUND 18Z TODAY. HOWEVER...LATEST HRRR SUGGESTS THIS
FEATURE WILL WEAKEN AS IT ENTERS OUR CWA ATT. HENCE...SLIGHT CHANCE
TO THE LOW END CHANCE POPS WERE WARRANTED THERE THROUGH THE MORNING
HOURS INTO EARLY PART OF THIS AFTERNOON. WITH TEMPS WARMING UP ABOVE
THE FREEZING LEVEL...SHRA WAS MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 78%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% MED 67%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
634 AM EST SAT DEC 27 2014
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. EXPECT TEMPERATURES TO BE A FEW DEGREES
ABOVE NORMAL THIS WEEKEND. THE FRONT WILL CROSS MONDAY WITH A
SECONDARY FRONT PASSING IN MID WEEK DROPPING TEMPERATURES TO BELOW
NORMAL. THE NEXT COLD FRONT WILL ARRIVE AT THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 60%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
922 PM CST SUN DEC 28 2014
.UPDATE...
THE FORECAST HAS BEEN UPDATED FOR THE REMAINDER OF TONIGHT INTO
EARLY MONDAY MORNING. THE MAIN UPDATE WAS TO ADD A MENTION OF
PATCHY FOG ACROSS THE RIO GRANDE PLAINS AND SOUTHERN EDWARDS
PLATEAU. MINOR UPDATES HAVE ALSO BEEN MADE TO THE LATEST
TEMPERATURES...DEW POINTS AND WINDS TO ACCOUNT FOR RECENT
OBSERVATIONS. FINALLY...WE DID DECREASE OVERNIGHT LOW TEMPERATURES
SLIGHTLY ACROSS THE NORTHWESTERN HILL COUNTRY.
&&
.PREV DISCUSSION... /ISSUED 602 PM CST SUN DEC 28 2014/
AVIATION.../00Z TAF CYCLE/
ALL SITES ARE VFR AND WILL BE SKC OVER THE NEXT COUPLE HOURS. A
SLIGHT CONCERN OVERNIGHT WILL BE SOME POSSIBLE MVFR FOG DEVELOPMENT
NEAR KSAT/KSSF AND KDRT 10Z THROUGH 15Z. CALM WINDS COMBINED WITH
IDEAL RADIATIONAL COOLING CONDITIONS OVERNIGHT WILL ALLOW FOR THE
BOUNDARY LAYER TO COOL SUBSTANTIALLY. HRRR OUTPUT AND NAMBUFR/RAP
SOUNDINGS POINT TOWARDS PATCHY FOG DEVELOPMENT ALONG WITH SOME HINTS
IN THE GFSLAMP AND NAM12 VISIBILITY GUIDANCE. HAVE TRENDED
KSAT/KSSF/KDRT TOWARD GFSLAMP GUIDANCE FOR NOW AND WILL MONITOR
UPDATED GUIDANCE FOR 06Z ISSUANCE IF IFR CONDITIONS APPEAR POSSIBLE.
/ALLEN/
PREV DISCUSSION... /ISSUED 335 PM CST SUN DEC 28 2014/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
AN UPPER LEVEL TROUGH IS EXITING TO THE EAST OF SOUTH CENTRAL
TEXAS THIS AFTERNOON. SKIES HAVE CLEARED TO NEAR I-35. SKIES WILL
CLEAR ACROSS THE REMAINDER OF OUR AREA BY SUNSET. THIS SETS THE
STAGE FOR WIDESPREAD FREEZING TEMPERATURES BY MONDAY MORNING. WE
HAVE ISSUED A FREEZE WARNING FOR LATE TONIGHT INTO MONDAY MORNING
FOR OUR SOUTHERN TWO TIERS OF COUNTIES...EXCEPT FOR THE SOUTHWEST.
THESE AREAS HAVE NOT YET REACHED FREEZING THIS FALL/WINTER.
MEANWHILE...THE HILL COUNTRY AND ALONG THE ESCARPMENT ALREADY HAVE
SEEN FREEZING TEMPERATURES THIS WINTER SEASON WHILE THE RIO GRANDE
PLAINS WILL FALL TO JUST ABOVE FREEZING. SEE OUR SPECIAL WEATHER
STATEMENT FOR DETAILS FOR THOSE AREAS. A BRIEF WARM UP IS EXPECTED
ON MONDAY ON SOUTH TO SOUTHWEST WINDS. LATE MONDAY NIGHT ANOTHER
COLD FRONT IS EXPECTED TO ENTER THE FAR NORTHERN HILL COUNTRY.
TEMPERATURES SHOULD STAY ABOVE FREEZING MONDAY NIGHT ON MIXING
ALONG AND AHEAD OF FRONT.
LONG TERM (TUESDAY THROUGH SUNDAY)...
THE COLD FRONT WILL SURGE ACROSS THE REMAINDER OF SOUTH CENTRAL
TEXAS TUESDAY MORNING. HIGH TEMPERATURES WILL BE REACHED LATE
MORNING TO MIDDAY AS CLOUDS INCREASE DUE TO MOIST SOUTHERLY FLOW
RIDING OVER COLD ADVECTION IN THE LOWER LEVELS. MODELS ARE IN
BETTER AGREEMENT ON THE PATTERN EVOLUTION IN THE LONG TERM.
ALTHOUGH...SOME DISAGREEMENT REMAINS AND THE FORECAST MAY CHANGE
OVER THE NEXT FEW DAYS. AN UPPER UPPER LEVEL TROUGH DROPPING DOWN
THE WEST COAST ON TUESDAY CLOSES OFF OVER SOUTHERN CALIFORNIA ON
WEDNESDAY INTO THURSDAY AND THEN OPENS UP AND MOVE ACROSS TEXAS
FRIDAY INTO EARLY SATURDAY. ISENTROPIC LIFT DEVELOPS TUESDAY NIGHT
INTO WEDNESDAY LEADING TO AREAS OF LIGHT RAIN INITIALLY ALONG THE
RIO GRANDE...THEN SPREADING ACROSS THE REMAINDER OF THE AREA.
PERIODS OF LIGHT TO OCCASIONALLY MODERATE RAIN OR SHOWERS WILL
CONTINUE THROUGH FRIDAY NIGHT. THERE IS A THREAT FOR WINTER TYPE
PRECIPITATION DURING THE LATE NIGHT INTO MORNING HOURS MAINLY FOR
PARTS OF THE HILL COUNTRY TUESDAY NIGHT THROUGH THURSDAY (NEW
YEARS DAY) MORNING. FORECAST SOUNDINGS SHOW A THICK LAYER ABOVE
FREEZING DEVELOPING ON TOP OF A SHALLOW SUBFREEZING BOUNDARY
LAYER. FREEZING RAIN IS THE LIKELY WINTER TYPE PRECIPITATION THAT
IS EXPECTED WHERE TEMPERATURES DROP BELOW FREEZING. HOWEVER...NO
SIGNIFICANT ICE ACCUMULATIONS ARE EXPECTED. SHOULD THE RAIN BECOME
MORE CONVECTIVE...THEN SOME SLEET MAY BE POSSIBLE OVER A GREATER
AREA. FINALLY...THERE MAY BE A THREAT OF LIGHT SNOW ACROSS WESTERN
EDWARDS PLATEAU PRIOR TO THE DEVELOPMENT OF THE WARM LAYER ALOFT.
BY THURSDAY AFTERNOON...THE LOWER LEVELS WARM ABOVE FREEZING WITH
ONLY A COLD RAIN EXPECTED. AS THE UPPER LOW APPROACHES AND MOVES
ACROSS...SOME THUNDERSTORMS ARE POSSIBLE DUE TO ELEVATED
INSTABILITY THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE RAINS END FROM
WEST TO EAST BY SATURDAY MORNING. FAIR SKIES AND MUCH WARMER
DAYTIME TEMPERATURES ARE EXPECTED NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 32 61 39 46 36 / 0 0 - 10 10
AUSTIN BERGSTROM INTL AIRPORT 25 60 35 46 36 / 0 0 - 10 10
NEW BRAUNFELS MUNI AIRPORT 29 61 36 48 38 / 0 0 - 10 10
BURNET MUNI AIRPORT 30 61 36 43 32 / 0 0 - 10 20
DEL RIO INTL AIRPORT 33 62 40 56 37 / 0 0 - 10 30
GEORGETOWN MUNI AIRPORT 28 60 35 44 34 / 0 0 - 10 10
HONDO MUNI AIRPORT 28 62 35 51 38 / 0 0 - 10 20
SAN MARCOS MUNI AIRPORT 29 61 36 47 37 / 0 0 - 10 10
LA GRANGE - FAYETTE REGIONAL 31 59 40 50 39 / 0 0 - 10 10
SAN ANTONIO INTL AIRPORT 32 62 39 49 38 / 0 0 - 10 20
STINSON MUNI AIRPORT 32 61 39 51 39 / 0 0 - 10 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 2 AM TO 9 AM CST MONDAY FOR THE FOLLOWING
COUNTIES: ATASCOSA...DE WITT...FAYETTE...FRIO...GONZALES...KARNES...
LAVACA...UVALDE...WILSON...ZAVALA.
&&
$$
MESOSCALE/AVIATION...15
SYNOPTIC/GRIDS...24
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
857 PM CST SUN DEC 28 2014
.DISCUSSION...
HIGH PRESSURE WILL BUILD OVERHEAD AS THE SHORTWAVE TROUGH MOVES
EASTWARD OF THE FORECAST AREA. EXPECT CLEARING CONDITIONS AND
COLDER TEMPERATURES OVERNIGHT TONIGHT. FORECAST SOUNDINGS AND
GUIDANCE ALSO IS FORECASTING PATCHY FOG. BECAUSE OF THE CLEARING
SKIES AND THE ABUNDANCE OF SURFACE MOISTURE DUE TO THE RAINFALL...
PATCHY FOG DOES LOOK MORE LIKELY.
UPDATE TO TAKE OUT RAINFALL CHANCES AND TO ADD PATCHY FOG
OVERNIGHT TONIGHT AND ENDING MID MORNING MONDAY.
40
&&
.PREV DISCUSSION... /ISSUED 553 PM CST SUN DEC 28 2014/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
LATEST RADAR TRENDS HAS RAIN ASSOCIATED WITH SHORT WAVE TROUGH
MOVING OUT OF THE AREA. THIS SHOULD ALLOW FOR VSBY/CIGS TO IMPROVE
THE NEXT SEVERAL HRS BUT STILL QUITE A BIT OF MOISTURE TRAPPED IN
COLD AIRMASS. SATELLITE IMAGERY SHOWS CLEARING LINE APPROACHING
KCLL FROM THE WEST. THIS MAY PUSH FAR ENOUGH EAST TO ALLOW FOR
IMPROVING CIGS BUT NOT SURE HOW FAR WEST IT WILL MOVE.
KCLL...THINK THERE SHOULD BE CLEARING FOR MOST OF THE NIGHT BUT
NOT SEEING MODELS INDICATE IF CIGS/VSBY FILL BACK IN THROUGH THE
MORNING WITH RADIATIONAL COOLING. WILL KEEP TAF VFR.
KUTS/KCXO/KIAH/KHOU/KSGR...WITH RAIN MOVING OUT EXPECT VSBY/CIGS
TO IMPROVE SOME. MAY BREAK OUT OF OVC IFR CONDITIONS TO BKN BUT
STILL POSSIBLE FOR IFR TO HOLD ON THROUGH MORNING. CONCERNED
CLEARING COULD OCCUR AS DRIER AIR TRIES TO MIX INTO THE AREA SO
WILL NEED TO WATCH FOR THAT AND MAY GET CIGS TO GO SCT FROM 03Z-
09Z. HRRR 19-21Z RUNS SHOW THIS TREND IN CIGS SCATTERING OUT BUT
THEN GET LOW IFR TO BUILD BACK IN FROM 09Z TO 15Z. TAFS WILL BE
GEARED TOWARDS THESE LOWER CIGS IN THE MORNING AND THEN SLOWLY
GOING IFR/MVFR WITH VFR BY LATE AFTERNOON TOMORROW. WITH HIGH
PRESSURE BUILDING IN...LIGHT WINDS EXPECTED.
KLBX/KGLS...MORE LIKELY THAT CLEARING WILL NOT OCCUR FROM THE WEST
FOR THESE TERMINALS SO HAVE MORE CONFIDENCE IN IFR CIGS HOLDING
THROUGH THE NIGHT. ALSO POSSIBLE FOR CIGS TO DROP IN THE MORNING
TO LOW IFR AS THERE WILL NOT BE ANY DRIER AIR TO MIX AS COMPARED
TO MORE INLAND SIGHTS. OTHERWISE TRENDS SHOULD BE SIMILAR TO
INLAND TERMINALS WITH IFR UNTIL LATE MORNING AND THE MVFR IN THE
AFTERNOON.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 33 58 38 51 35 / 10 0 0 10 10
HOUSTON (IAH) 36 59 42 57 38 / 10 0 0 10 10
GALVESTON (GLS) 43 57 48 56 44 / 10 0 0 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
602 PM CST SUN DEC 28 2014
.AVIATION.../00Z TAF CYCLE/
ALL SITES ARE VFR AND WILL BE SKC OVER THE NEXT COUPLE HOURS. A
SLIGHT CONCERN OVERNIGHT WILL BE SOME POSSIBLE MVFR FOG DEVELOPMENT
NEAR KSAT/KSSF AND KDRT 10Z THROUGH 15Z. CALM WINDS COMBINED WITH
IDEAL RADIATIONAL COOLING CONDITIONS OVERNIGHT WILL ALLOW FOR THE
BOUNDARY LAYER TO COOL SUBSTANTIALLY. HRRR OUTPUT AND NAMBUFR/RAP
SOUNDINGS POINT TOWARDS PATCHY FOG DEVELOPMENT ALONG WITH SOME HINTS
IN THE GFSLAMP AND NAM12 VISIBILITY GUIDANCE. HAVE TRENDED
KSAT/KSSF/KDRT TOWARD GFSLAMP GUIDANCE FOR NOW AND WILL MONITOR
UPDATED GUIDANCE FOR 06Z ISSUANCE IF IFR CONDITIONS APPEAR POSSIBLE.
/ALLEN/
&&
.PREV DISCUSSION... /ISSUED 335 PM CST SUN DEC 28 2014/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
AN UPPER LEVEL TROUGH IS EXITING TO THE EAST OF SOUTH CENTRAL
TEXAS THIS AFTERNOON. SKIES HAVE CLEARED TO NEAR I-35. SKIES WILL
CLEAR ACROSS THE REMAINDER OF OUR AREA BY SUNSET. THIS SETS THE
STAGE FOR WIDESPREAD FREEZING TEMPERATURES BY MONDAY MORNING. WE
HAVE ISSUED A FREEZE WARNING FOR LATE TONIGHT INTO MONDAY MORNING
FOR OUR SOUTHERN TWO TIERS OF COUNTIES...EXCEPT FOR THE SOUTHWEST.
THESE AREAS HAVE NOT YET REACHED FREEZING THIS FALL/WINTER.
MEANWHILE...THE HILL COUNTRY AND ALONG THE ESCARPMENT ALREADY HAVE
SEEN FREEZING TEMPERATURES THIS WINTER SEASON WHILE THE RIO GRANDE
PLAINS WILL FALL TO JUST ABOVE FREEZING. SEE OUR SPECIAL WEATHER
STATEMENT FOR DETAILS FOR THOSE AREAS. A BRIEF WARM UP IS EXPECTED
ON MONDAY ON SOUTH TO SOUTHWEST WINDS. LATE MONDAY NIGHT ANOTHER
COLD FRONT IS EXPECTED TO ENTER THE FAR NORTHERN HILL COUNTRY.
TEMPERATURES SHOULD STAY ABOVE FREEZING MONDAY NIGHT ON MIXING
ALONG AND AHEAD OF FRONT.
LONG TERM (TUESDAY THROUGH SUNDAY)...
THE COLD FRONT WILL SURGE ACROSS THE REMAINDER OF SOUTH CENTRAL
TEXAS TUESDAY MORNING. HIGH TEMPERATURES WILL BE REACHED LATE
MORNING TO MIDDAY AS CLOUDS INCREASE DUE TO MOIST SOUTHERLY FLOW
RIDING OVER COLD ADVECTION IN THE LOWER LEVELS. MODELS ARE IN
BETTER AGREEMENT ON THE PATTERN EVOLUTION IN THE LONG TERM.
ALTHOUGH...SOME DISAGREEMENT REMAINS AND THE FORECAST MAY CHANGE
OVER THE NEXT FEW DAYS. AN UPPER UPPER LEVEL TROUGH DROPPING DOWN
THE WEST COAST ON TUESDAY CLOSES OFF OVER SOUTHERN CALIFORNIA ON
WEDNESDAY INTO THURSDAY AND THEN OPENS UP AND MOVE ACROSS TEXAS
FRIDAY INTO EARLY SATURDAY. ISENTROPIC LIFT DEVELOPS TUESDAY NIGHT
INTO WEDNESDAY LEADING TO AREAS OF LIGHT RAIN INITIALLY ALONG THE
RIO GRANDE...THEN SPREADING ACROSS THE REMAINDER OF THE AREA.
PERIODS OF LIGHT TO OCCASIONALLY MODERATE RAIN OR SHOWERS WILL
CONTINUE THROUGH FRIDAY NIGHT. THERE IS A THREAT FOR WINTER TYPE
PRECIPITATION DURING THE LATE NIGHT INTO MORNING HOURS MAINLY FOR
PARTS OF THE HILL COUNTRY TUESDAY NIGHT THROUGH THURSDAY (NEW
YEARS DAY) MORNING. FORECAST SOUNDINGS SHOW A THICK LAYER ABOVE
FREEZING DEVELOPING ON TOP OF A SHALLOW SUBFREEZING BOUNDARY
LAYER. FREEZING RAIN IS THE LIKELY WINTER TYPE PRECIPITATION THAT
IS EXPECTED WHERE TEMPERATURES DROP BELOW FREEZING. HOWEVER...NO
SIGNIFICANT ICE ACCUMULATIONS ARE EXPECTED. SHOULD THE RAIN BECOME
MORE CONVECTIVE...THEN SOME SLEET MAY BE POSSIBLE OVER A GREATER
AREA. FINALLY...THERE MAY BE A THREAT OF LIGHT SNOW ACROSS WESTERN
EDWARDS PLATEAU PRIOR TO THE DEVELOPMENT OF THE WARM LAYER ALOFT.
BY THURSDAY AFTERNOON...THE LOWER LEVELS WARM ABOVE FREEZING WITH
ONLY A COLD RAIN EXPECTED. AS THE UPPER LOW APPROACHES AND MOVES
ACROSS...SOME THUNDERSTORMS ARE POSSIBLE DUE TO ELEVATED
INSTABILITY THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE RAINS END FROM
WEST TO EAST BY SATURDAY MORNING. FAIR SKIES AND MUCH WARMER
DAYTIME TEMPERATURES ARE EXPECTED NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 32 61 39 46 36 / 0 0 - 10 10
AUSTIN BERGSTROM INTL AIRPORT 25 60 35 46 36 / 0 0 - 10 10
NEW BRAUNFELS MUNI AIRPORT 29 61 36 48 38 / 0 0 - 10 10
BURNET MUNI AIRPORT 30 61 36 43 32 / 0 0 - 10 20
DEL RIO INTL AIRPORT 33 62 40 56 37 / 0 0 - 10 30
GEORGETOWN MUNI AIRPORT 28 60 35 44 34 / 0 0 - 10 10
HONDO MUNI AIRPORT 28 62 35 51 38 / 0 0 - 10 20
SAN MARCOS MUNI AIRPORT 29 61 36 47 37 / 0 0 - 10 10
LA GRANGE - FAYETTE REGIONAL 31 59 40 50 39 / 0 0 - 10 10
SAN ANTONIO INTL AIRPORT 32 62 39 49 38 / 0 0 - 10 20
STINSON MUNI AIRPORT 32 61 39 51 39 / 0 0 - 10 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 2 AM TO 9 AM CST MONDAY FOR THE FOLLOWING
COUNTIES: ATASCOSA...DE WITT...FAYETTE...FRIO...GONZALES...KARNES...
LAVACA...UVALDE...WILSON...ZAVALA.
&&
$$
MESOSCALE/AVIATION...15
SYNOPTIC/GRIDS...24
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
553 PM CST SUN DEC 28 2014
.DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
&&
.AVIATION...
LATEST RADAR TRENDS HAS RAIN ASSOCIATED WITH SHORT WAVE TROUGH
MOVING OUT OF THE AREA. THIS SHOULD ALLOW FOR VSBY/CIGS TO IMPROVE
THE NEXT SEVERAL HRS BUT STILL QUITE A BIT OF MOISTURE TRAPPED IN
COLD AIRMASS. SATELLITE IMAGERY SHOWS CLEARING LINE APPROACHING
KCLL FROM THE WEST. THIS MAY PUSH FAR ENOUGH EAST TO ALLOW FOR
IMPROVING CIGS BUT NOT SURE HOW FAR WEST IT WILL MOVE.
KCLL...THINK THERE SHOULD BE CLEARING FOR MOST OF THE NIGHT BUT
NOT SEEING MODELS INDICATE IF CIGS/VSBY FILL BACK IN THROUGH THE
MORNING WITH RADIATIONAL COOLING. WILL KEEP TAF VFR.
KUTS/KCXO/KIAH/KHOU/KSGR...WITH RAIN MOVING OUT EXPECT VSBY/CIGS
TO IMPROVE SOME. MAY BREAK OUT OF OVC IFR CONDITIONS TO BKN BUT
STILL POSSIBLE FOR IFR TO HOLD ON THROUGH MORNING. CONCERNED
CLEARING COULD OCCUR AS DRIER AIR TRIES TO MIX INTO THE AREA SO
WILL NEED TO WATCH FOR THAT AND MAY GET CIGS TO GO SCT FROM 03Z-
09Z. HRRR 19-21Z RUNS SHOW THIS TREND IN CIGS SCATTERING OUT BUT
THEN GET LOW IFR TO BUILD BACK IN FROM 09Z TO 15Z. TAFS WILL BE
GEARED TOWARDS THESE LOWER CIGS IN THE MORNING AND THEN SLOWLY
GOING IFR/MVFR WITH VFR BY LATE AFTERNOON TOMORROW. WITH HIGH
PRESSURE BUILDING IN...LIGHT WINDS EXPECTED.
KLBX/KGLS...MORE LIKELY THAT CLEARING WILL NOT OCCUR FROM THE WEST
FOR THESE TERMINALS SO HAVE MORE CONFIDENCE IN IFR CIGS HOLDING
THROUGH THE NIGHT. ALSO POSSIBLE FOR CIGS TO DROP IN THE MORNING
TO LOW IFR AS THERE WILL NOT BE ANY DRIER AIR TO MIX AS COMPARED
TO MORE INLAND SIGHTS. OTHERWISE TRENDS SHOULD BE SIMILAR TO
INLAND TERMINALS WITH IFR UNTIL LATE MORNING AND THE MVFR IN THE
AFTERNOON.
39
&&
.PREV DISCUSSION... /ISSUED 340 PM CST SUN DEC 28 2014/
DISCUSSION...
TODAY/S PERSISTENT SHOWER ACTIVITY HAS NOW STARTED TO CLEAR THE
WESTERNMOST COUNTIES AS OF 3 PM /GENERALLY AREAS WEST OF THE
BRAZOS RIVER/. THIS ACTIVITY WILL CONTINUE TO PRODUCE LIGHT
RAINFALL TOTALS INTO THE EVENING HOURS AS IT TRANSLATES EAST AHEAD
OF A COMPACT SHORTWAVE TROUGH MOVING ACROSS THE STATE. THE EDGE OF
THE CLOUD DECK ASSOCIATED WITH THE RAIN LAGS BEHIND THE END OF THE
RAINFALL AND IS NOT ANTICIPATED TO REACH SOUTHEAST TEXAS UNTIL
LATER THIS EVENING. WHILE IT SEEMS RELATIVELY BENIGN...THE
TIMING/EVOLUTION OF THIS CLOUD DECK WILL ACTUALLY PLAY A VERY
IMPORTANT ROLE IN THE SHORT TERM FORECAST IN TERMS OF OVERNIGHT
LOW TEMPERATURES AND THE POTENTIAL FOR FOG DEVELOPMENT.
SIMPLE EXTRAPOLATION OF THE WESTERN EDGE OF THE CLOUD DECK FROM
VISIBLE SATELLITE SHOWS THIS CLEARING REACHING THE WESTERN EDGE OF
THE FORECAST AREA AROUND 00-02Z...AND MODEL GUIDANCE SHOWS THE
CLEARING LINE PUSHING EAST THROUGH THE OVERNIGHT HOURS. THERE/S
STILL SOME UNCERTAINTY ON HOW FAR EAST THE LINE WILL PUSH
THOUGH...WITH GENERAL CONSENSUS SHOWING IT REACHING NEAR THE I-45
CORRDIOR EARLY MONDAY MORNING. AS THIS LINE PUSHES EAST...THE
WESTERN AREAS WILL BE ALLOWED THE OPPORTUNITY TO RADIATIONALLY
COOL ENOUGH TO EXPERIENCE A LIGHT/BRIEF FREEZE. IF THE CLOUDS DO
NOT CLEAR AS QUICKLY /OR CLEAR FASTER/...OVERNIGHT LOW
TEMPERATURES WILL BE AFFECTED WITH THE ADDITION /OR LOSS/ OF A
CLOUD BLANKET. ADDITIONALLY...RELATIVELY LIGHT WINDS OVERNIGHT
WILL KEEP MIXING TO A MINIMUM...RAISING THE POTENTIAL FOR SOME FOG
DEVELOPMENT /ESPECIALLY IN AREAS THAT CLEAR/. LATEST RAP AND HRRR
VISIBILITY PROGS OFFER CONSIDERABLE DISAGREEMENT ON WHETHER OR NOT
FOG WILL DEVELOP. FOR NOW...WILL LEAVE PATCHY FOG MENTION OUT OF
THE FORECAST BUT ISOLATED DEVELOPMENT IS STILL POSSIBLE.
THE GENERAL UPPER AIR PATTERN THIS AFTERNOON HAS CONSISTED OF A
LONGWAVE TROUGH DRAPED ACROSS THE CONUS...WITH SEVERAL
DISTURBANCES ROTATING THROUGH THIS FEATURE. THE MOST NOTICEABLE
FOR US HAS BEEN THE ONE RESPONSIBLE FOR TODAY/S RAIN. TWO
DISTURBANCES FARTHER UPSTREAM /ONE OVER THE NORTHWESTERN CONUS AND
ANOTHER OVER THE NORTHWEST TERRITORIES OF CANADA/ WILL IMPACT THE
REGION/S WEATHER LATER IN THE WEEK. BEHIND TODAY/S SHORTWAVE... A
GENERALLY ZONAL FLOW BECOMES ESTABLISHED ACROSS THE SOUTHERN
CONUS. DESPITE THE PRESENCE OF AT LEAST PARTLY CLOUDY SKIES
MONDAY... ENOUGH INSOLATION WILL REACH THE SURFACE TO ALLOW
TEMPERATURES TO REBOUND INTO THE MID TO UPPER 50S.
MONDAY/S WARM UP WILL BE SHORT-LIVED AS THE DISTURBANCE OVER THE
NW CONUS CROSSES THE CENTRAL PLAINS WITH AN ARCTIC AIRMASS OOZING
THE AREA TUESDAY THROUGH THURSDAY. NORTHERLY WINDS WILL INCREASE
AS THE LEADING EDGE OF THIS ARCTIC AIR MOVES INTO THE AREA ON
TUESDAY...AND TEMPERATURES STILL REMAIN A CONCERN WITH THIS
SYSTEM. THE EXTENT OF THE MODIFICATION OF THE AIRMASS /FROM EITHER
DIABATIC OR ADIABATIC PROCESSES/ IS STILL NOT ENTIRELY CLEAR...BUT
WILL CONTINUE THE TREND OF GOING BELOW MODEL GUIDANCE AS THE EVENT
EVOLVES. THIS LEAVES THE OUTLOOK FOR MID-WEEK CHILLY WITH HIGHS
WEDNESDAY AND THURSDAY IN THE MID 40S TO NEAR 50.
THE FORMERLY CANADIAN SHORTWAVE DROPS TOWARDS THE FOUR CORNERS
REGION BY WEDNESDAY...ESTABLISHING A SOUTHWEST FLOW ALOFT /WHICH
ALLOWS FOR SOME MID LEVEL MOISTURE RETURN INTO THE REGION/ AND
INCREASING ISENTROPIC LIFT. RAIN CHANCES WILL NOT BEGIN TO
INCREASE UNTIL THURSDAY WITH THIS LIFT...AS FORECAST SOUNDINGS
SHOW RELATIVELY DRY LOWER LEVELS WILL PREVENT ANY PRECIPITATION
THAT DEVELOPS FROM REACHING THE GROUND. GUIDANCE INDICATES A
SUBTLE SHORTWAVE TROUGH MAY TRANSLATE NORTHWEST OF THE AREA LATE
THURSDAY...POSSIBLY INCREASING RAIN CHANCES FOR THE NORTHWEST
ZONES...BUT THE REGION MAY BE TOO FAR AWAY FROM THIS EXTRA SOURCE
OF LIFT TO ENHANCE OUR CHANCES.
BY FRIDAY...THUNDERSTORM CHANCES ARE ON THE INCREASE AS A COASTAL
TROUGH AND ASSOCIATED WARM FRONT DEVELOP ALONG THE TEXAS COAST.
STILL SOME QUESTIONS REGARDING EXTENT OF GULF MOISTURE
RETURN...BUT ENOUGH INSTABILITY APPEARS PRESENT AT THIS POINT TO
CONTINUE THUNDERSTORM CHANCES FRIDAY INTO FRIDAY NIGHT. AS THE
CANADIAN SHORTWAVE CROSSES TEXAS...ANOTHER COLD FRONT WILL REACH
THE AREA AND END RAIN CHANCES HEADING INTO LATE SATURDAY.
HUFFMAN
MARINE...
BOTH NORTH WINDS AND SEAS WILL DECREASE TONIGHT AND MONDAY AS HIGH
PRESSURE MOVES OVER THE AREA. THE NEXT COLD FRONT MONDAY NIGHT THROUGH
TUESDAY MORNING WILL BRING STRENGTHENING NORTHEAST WINDS ACROSS THE
WATERS. CAUTION FLAGS ARE LIKELY...AND ADVISORIES MIGHT BE NEEDED
TUESDAY THROUGH THURSDAY NIGHT. SOUTH WINDS ARE EXPECTED TO RETURN ON
FRIDAY AND FRIDAY NIGHT AS A WARM FRONT MOVES INLAND. LIGHT TO MODERATE
NORTH WINDS COME BACK OVER THE WEEKEND. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 33 58 38 51 35 / 10 0 0 10 10
HOUSTON (IAH) 36 59 42 57 38 / 10 0 0 10 10
GALVESTON (GLS) 43 57 48 56 44 / 20 0 0 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
400 PM CST Sat Dec 27 2014
.DISCUSSION...
Current observations continue to show intermittent light snow
continuing over portions of southeast New Mexico and the western
Permian Basin. Significant snows have ended over the Guadalupe
Mountains and across Lea County New Mexico. The HRRR and other
models suggest that lingering precipitation over these northern
areas will continue to wane while redevelopment will occur over the
higher elevations of SW Texas beginning later this afternoon into evening.
While indications are that the positive tilt upper trough is
weakening/filling as it moves across the area, which is a negative
against significant snow, current QFP for this evening and BUFKIT
sounding interrogation suggests that snow redevelopment is
likely...especially over the higher elevations of SW Texas. The
Marfa Plateau and the Davis Mountains could see significant snowfall
tonight. The western half of Pecos county could also see some minor
snow accumulations. For now, will issue a winter storm warning for
heavy snow for higher elevations of Presidio, Jeff Davis, and
Brewster County. A winter weather advisory will be issued for Pecos
County. Both the warning and advisory will be extended into the
overnight period. However, most of the activity will probably occur
this evening.
As this upper trough rapidly exits the area tomorrow morning, zonal
upper flow is expected. Surface lee trough development just east of
the Rockies will result in a quick warmup for our area tomorrow and
Monday. However, a significant cool down is forecast for later
Monday into Tuesday. The big question for now is what type of
precipitation will fall next week. With shallow cold air in place
and an expected elevated warm later, indications are that freezing
drizzle will the predominant precipitation type most of next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 26 48 29 56 / 20 0 0 0
BIG SPRING TX 28 51 33 59 / 20 0 0 0
CARLSBAD NM 22 50 30 56 / 10 0 0 0
DRYDEN TX 34 53 33 62 / 60 0 0 0
FORT STOCKTON TX 28 53 37 63 / 60 0 0 0
GUADALUPE PASS TX 22 41 30 51 / 10 0 0 0
HOBBS NM 22 46 26 54 / 10 0 0 0
MARFA TX 20 48 19 60 / 70 10 0 0
MIDLAND INTL AIRPORT TX 25 50 30 57 / 20 0 0 0
ODESSA TX 26 50 33 57 / 20 0 0 0
WINK TX 26 53 27 63 / 30 0 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...WINTER WEATHER ADVISORY until 3 AM CST Sunday FOR THE FOLLOWING
ZONES... Pecos.
WINTER STORM WARNING until 3 AM CST Sunday FOR THE FOLLOWING
ZONES... Big Bend Area...Davis/Apache Mountains Area...
Marfa Plateau.
&&
$$
84/03
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AREA FORECAST DISCUSSION
NWS FORT WORTH TX
254 PM CST SAT DEC 27 2014
.DISCUSSION...
THE SHORTWAVE DISTURBANCE THAT CREATED SOME WINTER PRECIPITATION
ACROSS OUR FAR NORTHWEST COUNTIES THIS PAST MORNING IS SLOWLY
EXITING THE AREA...THOUGH A FEW SLEET PELLETS REMAIN POSSIBLE WITH
ANY LINGERING LIGHT RAIN. THE SURFACE COLD FRONT IS NOW APPROACHING
THE TEXAS COAST WITH CLOUDY...WINDY AND COLD CONDITIONS ACROSS
NORTH AND CENTRAL TEXAS. SCATTERED AREAS OF LIGHT RAIN WILL LINGER
ACROSS THE FAR EAST AND SOUTHEAST COUNTIES TONIGHT INTO SUNDAY...AS
THE LARGER SCALE UPPER TROUGH MOVES EAST ACROSS THE AREA ON ON
SUNDAY. AREAS FURTHER NORTH AND WEST WILL CONTINUE TO SEE DRIER
POLAR AIR INTRUDING IN WITH JUST BRISK AND COLD CONDITIONS CONTINUING
THIS PERIOD. WE DID LOWER HIGH TEMPERATURES ON SUNDAY INTO THE 40S
TO ACCOUNT FOR SOME LINGERING CLOUDINESS AND WEAK CAA ASSOCIATED
WITH THE PASSING MAIN UPPER TROUGH.
THE FLOW ALOFT BECOMES ZONAL THE FIRST HALF OF THIS WEEK HEADING
INTO THE NEW YEAR. AN ELONGATED SHORTWAVE TROUGH WILL DIG SOUTHWEST
ACROSS THE GREAT BASIN OF NEVADA/UTAH/ARIZONA DURING THIS TIME. AT
THE SURFACE...RETURNING SOUTHERLY WINDS WILL WARM IT UP BRIEFLY ON
MONDAY TO BETWEEN 55 AND 65 DEGREES...BEFORE A SHALLOW ARCTIC COLD
FRONT ARRIVES EARLY TUESDAY. THOUGH CHILLY AND BRISK CONDITIONS
ARRIVE FOR THE MIDDLE PART OF THE WEEK...A BULK OF THE BETTER RAIN
CHANCES WILL REMAIN SOUTH AND WEST OF OUR AREA. THE ENERGY OUT
WEST IS STARTING TO SHOW SIGNS OF CLOSING OFF OVER ARIZONA BY
WEDNESDAY...BUT A LEAD SHORTWAVE WILL LIFT NORTHEAST OVER THE AREA
AND INDUCE ISENTROPIC ASCENT OVER THE SHALLOW ARCTIC AIR BY
WEDNESDAY NIGHT INTO THURSDAY WITH MODELS DIFFERING SOMEWHAT ON
ENVIRONMENTAL PROFILES...PRECIP TYPES...AND OVERALL TEMPERATURES.
SO CONFIDENCE ON THE OVERALL EVOLUTION OF ANY WINTER WEATHER
LATER IN THE WEEK REMAINS LOW...BUT APPEARS SOME CHANCE OF A MIX
WILL BE THERE WITH CHILLY CONDITIONS CONTINUING.
THE GREAT BASIN UPPER LOW WILL FINALLY BEGIN TO EJECT EAST TOWARD
AND ACROSS NORTH AND CENTRAL TEXAS AT THE END OF THE WEEK...AS
ANOTHER STRONG SHORTWAVE DROPS OVER THE PACIFIC NORTHWEST. MEDIUM
RANGE MODELS REALLY BEGIN DIVERGING BY FRIDAY INTO SATURDAY AS THE
OPEN TROUGH LIFTS ACROSS THE SOUTHERN PLAINS. THE GFS IS MUCH
QUICKER AND NORTH WITH IT...WHILE THE EUROPEAN SLOWER AND FURTHER
SOUTH. WITH THE SOUTHEASTERN U.S UPPER HIGH REMAINING RELATIVELY
STRONG OVER THE GULF OF MEXICO AND FLORIDA...THE EUROPEAN MODEL
SOLUTION APPEARS MORE LIKELY WITH GRADUAL MODERATING TEMPERATURES
AND CHANCES FOR RAIN AND THUNDERSTORMS THURSDAY NIGHT THROUGH
SATURDAY MORNING. WE SHOULD KNOW MORE ON DETAILS OF FUTURE SYSTEMS
IN THE COMING DAYS...BUT UNTIL THEN WE WILL JUST REMAIN
CONSERVATIVE UNTIL THEY BECOME MORE CLEAR.
05/
&&
.AVIATION...
AS /ISSUED 208 PM CST SAT DEC 27 2014/
LOOKS LIKE THE SHOWERS MOISTENED UP THE LOWER LEVELS ENOUGH FOR
MVFR CEILINGS. THEY SHOULD PERSIST UNTIL THE DRIER NEAR THE LINE
FROM WICHITA FALLS TO OKLAHOMA CITY GETS INTO THE AREA MID EVENING.
84
/PREVIOUS AVIATION DISCUSSION/
12Z GFS/NAM AND THEIR MOS CAME IN DRIER TODAY...BUT I AM LOOKING
AT THE PRECIP BAND WEST OF THE METROPLEX AND IT EXTRAPOLATES INTO
THE TAF SITES MID AFTERNOON. HRRR WEAKENS PRECIP BUT CONTINUES
IT. GIVEN WHAT I SEE TO OUR WEST I THINK THERE WILL BE SOME
PRECIP AT THE METROPLEX AIRPORTS. LIGHT SHOWERS ARE ALSO
INCREASING EAST OF THE BAND...AND I STARTED THE TAFS OUT WITH
VCSH. 850MB TEMPS ARE PROGGED TO REMAIN WARMER THAN FARTHER
WEST...SO I DO NOT SEE ANY PRECIP TYPES OTHER THAN RAIN. AS THE
SUPPORTING SHORT WAVE MOVES NORTHEAST...LOWER LEVELS WILL DRY OUT
AND I DROPPED THE RAIN AFTER SUNSET. 84
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 33 49 33 58 33 / 20 5 0 0 0
WACO, TX 35 50 31 61 34 / 20 10 0 0 0
PARIS, TX 33 48 31 55 31 / 30 5 0 0 0
DENTON, TX 31 49 32 57 29 / 20 5 0 0 0
MCKINNEY, TX 32 48 32 57 30 / 20 5 0 0 0
DALLAS, TX 34 49 34 59 34 / 20 5 0 0 0
TERRELL, TX 34 49 32 58 34 / 30 5 0 0 0
CORSICANA, TX 36 50 33 60 35 / 30 20 0 0 0
TEMPLE, TX 35 50 32 62 34 / 20 20 0 0 0
MINERAL WELLS, TX 29 49 31 58 28 / 10 5 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
208 PM CST SAT DEC 27 2014
.AVIATION...
LOOKS LIKE THE SHOWERS MOISTENED UP THE LOWER LEVELS ENOUGH FOR
MVFR CEILINGS. THEY SHOULD PERSIST UNTIL THE DRIER NEAR THE LINE
FROM WICHITA FALLS TO OKLAHOMA CITY GETS INTO THE AREA MID EVENING.
84
/PREVIOUS AVIATION DISCUSSION/
12Z GFS/NAM AND THEIR MOS CAME IN DRIER TODAY...BUT I AM LOOKING
AT THE PRECIP BAND WEST OF THE METROPLEX AND IT EXTRAPOLATES INTO
THE TAF SITES MID AFTERNOON. HRRR WEAKENS PRECIP BUT CONTINUES
IT. GIVEN WHAT I SEE TO OUR WEST I THINK THERE WILL BE SOME
PRECIP AT THE METROPLEX AIRPORTS. LIGHT SHOWERS ARE ALSO
INCREASING EAST OF THE BAND...AND I STARTED THE TAFS OUT WITH
VCSH. 850MB TEMPS ARE PROGGED TO REMAIN WARMER THAN FARTHER
WEST...SO I DO NOT SEE ANY PRECIP TYPES OTHER THAN RAIN. AS THE
SUPPORTING SHORT WAVE MOVES NORTHEAST...LOWER LEVELS WILL DRY OUT
AND I DROPPED THE RAIN AFTER SUNSET. 84
&&
.UPDATE...
WE HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FOR LIGHT
SNOW...POSSIBLY MIXED WITH LIGHT SLEET AT TIMES ACROSS NORTHERN
STEPHENS...YOUNG...JACK...AND MONTAGUE COUNTIES THROUGH MID
AFTERNOON. COLD AIR NOW IS ENTRENCHED ACROSS ALL OF NORTH TEXAS
WITH THE COLDEST TEMPERATURES JUST ABOVE FREEZING ACROSS OUR FAR
NORTHWEST COUNTIES. A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT
OF THE WESTERN CONUS MAIN LONGWAVE TROUGH IS INCREASING THE THE
MID LEVEL FRONTOGENETICAL FORCING ACROSS THE NORTHWEST COUNTIES.
SEVERAL REPORTS OF LIGHT SNOW WITH SOME SLEET HAVE OCCURRED ACROSS
YOUNG COUNTY WHERE BANDING IS NOTED ON REGIONAL RADAR. LOCAL
LAPS AND RUC SOUNDINGS ACROSS THIS REGION INDICATE POTENTIAL FOR
LIGHT SNOW AND SLEET TO CONTINUE NEXT FEW HOURS WITH A NORTHEAST
TRAJECTORY.
IN ADDITION...THIS IS A HIGH TRAVEL-VOLUME DAY AFTER THE HOLIDAYS
AND WILL GIVE COMMUTERS HEADING NORTHEAST TOWARD THIS AREA SOME
INDICATION OF SLICK SPOTS...ESPECIALLY ON BRIDGES...OVERPASSES...
AND SECONDARY ROADS.
05/
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 32 50 33 58 33 / 20 5 5 5 5
WACO, TX 34 49 32 61 34 / 20 10 5 5 5
PARIS, TX 33 49 32 55 31 / 30 5 5 5 5
DENTON, TX 29 50 32 57 29 / 20 5 5 5 5
MCKINNEY, TX 31 49 32 57 30 / 20 5 5 5 5
DALLAS, TX 33 50 34 59 34 / 20 5 5 5 5
TERRELL, TX 34 50 32 58 34 / 30 5 5 5 5
CORSICANA, TX 35 49 33 60 35 / 30 10 5 5 5
TEMPLE, TX 34 49 32 61 34 / 20 20 5 5 5
MINERAL WELLS, TX 28 49 31 58 28 / 10 5 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ091-
100-101-115.
&&
$$
/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1137 AM CST SAT DEC 27 2014
.AVIATION...
12Z GFS/NAM AND THEIR MOS CAME IN DRIER TODAY...BUT I AM LOOKING
AT THE PRECIP BAND WEST OF THE METROPLEX AND IT EXTRAPOLATES INTO
THE TAF SITES MID AFTERNOON. HRRR WEAKENS PRECIP BUT CONTINUES
IT. GIVEN WHAT I SEE TO OUR WEST I THINK THERE WILL BE SOME
PRECIP AT THE METROPLEX AIRPORTS. LIGHT SHOWERS ARE ALSO
INCREASING EAST OF THE BAND...AND I STARTED THE TAFS OUT WITH
VCSH. 850MB TEMPS ARE PROGGED TO REMAIN WARMER THAN FARTHER
WEST...SO I DO NOT SEE ANY PRECIP TYPES OTHER THAN RAIN. AS THE
SUPPORTING SHORT WAVE MOVES NORTHEAST...LOWER LEVELS WILL DRY OUT
AND I DROPPED THE RAIN AFTER SUNSET. 84
&&
.UPDATE...
WE HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FOR LIGHT
SNOW...POSSIBLY MIXED WITH LIGHT SLEET AT TIMES ACROSS NORTHERN
STEPHENS...YOUNG...JACK...AND MONTAGUE COUNTIES THROUGH MID
AFTERNOON. COLD AIR NOW IS ENTRENCHED ACROSS ALL OF NORTH TEXAS
WITH THE COLDEST TEMPERATURES JUST ABOVE FREEZING ACROSS OUR FAR
NORTHWEST COUNTIES. A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT
OF THE WESTERN CONUS MAIN LONGWAVE TROUGH IS INCREASING THE THE
MID LEVEL FRONTOGENETICAL FORCING ACROSS THE NORTHWEST COUNTIES.
SEVERAL REPORTS OF LIGHT SNOW WITH SOME SLEET HAVE OCCURRED ACROSS
YOUNG COUNTY WHERE BANDING IS NOTED ON REGIONAL RADAR. LOCAL
LAPS AND RUC SOUNDINGS ACROSS THIS REGION INDICATE POTENTIAL FOR
LIGHT SNOW AND SLEET TO CONTINUE NEXT FEW HOURS WITH A NORTHEAST
TRAJECTORY.
IN ADDITION...THIS IS A HIGH TRAVEL-VOLUME DAY AFTER THE HOLIDAYS
AND WILL GIVE COMMUTERS HEADING NORTHEAST TOWARD THIS AREA SOME
INDICATION OF SLICK SPOTS...ESPECIALLY ON BRIDGES...OVERPASSES...
AND SECONDARY ROADS.
05/
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 42 32 50 33 58 / 40 20 5 5 5
WACO, TX 46 34 49 32 61 / 40 20 10 5 5
PARIS, TX 43 33 49 32 55 / 40 30 5 5 5
DENTON, TX 40 29 50 32 57 / 50 20 5 5 5
MCKINNEY, TX 41 31 49 32 57 / 40 20 5 5 5
DALLAS, TX 43 33 50 34 59 / 40 20 5 5 5
TERRELL, TX 45 34 50 32 58 / 40 30 5 5 5
CORSICANA, TX 47 35 49 33 60 / 40 30 10 5 5
TEMPLE, TX 46 34 49 32 61 / 40 20 20 5 5
MINERAL WELLS, TX 41 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ091-
100-101-115.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1111 AM CST SAT DEC 27 2014
.UPDATE...
WE HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FOR LIGHT
SNOW...POSSIBLY MIXED WITH LIGHT SLEET AT TIMES ACROSS NORTHERN
STEPHENS...YOUNG...JACK...AND MONTAGUE COUNTIES THROUGH MID
AFTERNOON. COLD AIR NOW IS ENTRENCHED ACROSS ALL OF NORTH TEXAS
WITH THE COLDEST TEMPERATURES JUST ABOVE FREEZING ACROSS OUR FAR
NORTHWEST COUNTIES. A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT
OF THE WESTERN CONUS MAIN LONGWAVE TROUGH IS INCREASING THE THE
MID LEVEL FRONTOGENETICAL FORCING ACROSS THE NORTHWEST COUNTIES.
SEVERAL REPORTS OF LIGHT SNOW WITH SOME SLEET HAVE OCCURRED ACROSS
YOUNG COUNTY WHERE BANDING IS NOTED ON REGIONAL RADAR. LOCAL
LAPS AND RUC SOUNDINGS ACROSS THIS REGION INDICATE POTENTIAL FOR
LIGHT SNOW AND SLEET TO CONTINUE NEXT FEW HOURS WITH A NORTHEAST
TRAJECTORY.
IN ADDITION...THIS IS A HIGH TRAVEL-VOLUME DAY AFTER THE HOLIDAYS
AND WILL GIVE COMMUTERS HEADING NORTHEAST TOWARD THIS AREA SOME
INDICATION OF SLICK SPOTS...ESPECIALLY ON BRIDGES...OVERPASSES...
AND SECONDARY ROADS.
05/
&&
.AVIATION...
/ISSUED 553 AM CST SAT DEC 27 2014/
A COLD FRONT HAD MOVED THROUGH ALL TAF SITES AS OF 530 AM. THE
PASSAGE OF THE FRONT BROUGHT DRIER AIR AND LIFTING CEILINGS. MVFR
CONDITIONS WILL PREVAIL THROUGH SUNRISE WITH CEILINGS LIFTING
ABOVE 3000 FT BY MID TO LATE MORNING. SCATTERED LIGHT SHOWERS ARE
POSSIBLE THROUGH THE MORNING BUT THE BETTER RAIN CHANCES WILL
ARRIVE THIS AFTERNOON AS LARGE SCALE LIFT ASSOCIATED WITH A
APPROACHING UPPER TROUGH INCREASES. ANY SHOWERS THAT DEVELOP THIS
AFTERNOON WILL BE RELATIVELY LIGHT BUT MAY BE ACCOMPANIED BY MVFR
CEILINGS. A FEW SHOWERS COULD LINGER OVERNIGHT BUT COVERAGE WILL
BE TOO LIMITED TO INCLUDE IN THIS FORECAST. VFR CONDITIONS WILL PREVAIL
TONIGHT WITH SCATTERED TO BROKEN MIDDLE AND UPPER LEVEL CLOUDS.
A NORTH WIND WILL PREVAIL BETWEEN 16 AND 20 KNOTS TODAY WITH SOME
GUSTS UP TO ABOUT 27 KNOTS. WIND SPEEDS SHOULD FALL BELOW 15 KNOTS
BY MID EVENING.
79
&&
.PREV UPDATE...
.UPDATE...
MINOR UPDATE TO ADJUST AND CLEAN UP POPS AND CHANCES. A FEW
REPORTS OF WINTRY MIX OF WINTER PRECIPITATION ACROSS WESTERN YOUNG
AND STEPHENS COUNTIES...BUT TEMPERATURES ARE IN THE MID 30S AND
ROADS ARE MOSTLY WET...THOUGH ELEVATED SURFACES HAVE TO BE
WATCHED OUT THAT WAY. DUE TO LIMITED...IF ANY IMPACTS...WE DO NOT
PLAN ON ISSUING ANY ADVISORIES THROUGH TODAY AS THIS SHORTWAVE
LIFTS OUT READILY TO THE NORTHEAST AND TEMPERATURES REMAIN MOSTLY
STEADY STATE. WE WILL BE WATCHING FOR ANY POSSIBLE WET-BULB
EFFECTS HOWEVER TO THE NORTHWEST OF THE DFW METRO.
OTHERWISE...A FEW ELEVATED SHOWERS AND STORMS ABOVE THE FRONTAL
INVERSION ACROSS THE SOUTHEAST COUNTIES THROUGH THIS AFTERNOON.
CAN/T RULE OUT A LITTLE PEA HAIL WITH STRONGEST ACTIVITY. IT WILL
REMAIN MAINLY CLOUDY...WINDY AND COLD THROUGHOUT THE DAY WITH ONLY
A SLOW DROP IN TEMPS WITH CONTINUED CAA.
05/
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 42 32 50 33 58 / 40 20 5 5 5
WACO, TX 46 34 49 32 61 / 40 20 10 5 5
PARIS, TX 43 33 49 32 55 / 40 30 5 5 5
DENTON, TX 40 29 50 32 57 / 50 20 5 5 5
MCKINNEY, TX 41 31 49 32 57 / 40 20 5 5 5
DALLAS, TX 43 33 50 34 59 / 40 20 5 5 5
TERRELL, TX 45 34 50 32 58 / 40 30 5 5 5
CORSICANA, TX 47 35 49 33 60 / 40 30 10 5 5
TEMPLE, TX 46 34 49 32 61 / 40 20 20 5 5
MINERAL WELLS, TX 41 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ091-
100-101-115.
&&
$$
79/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1015 AM CST SAT DEC 27 2014
.UPDATE...
MINOR UPDATE TO ADJUST AND CLEAN UP POPS AND CHANCES. A FEW
REPORTS OF WINTRY MIX OF WINTER PRECIPITATION ACROSS WESTERN YOUNG
AND STEPHENS COUNTIES...BUT TEMPERATURES ARE IN THE MID 30S AND
ROADS ARE MOSTLY WET...THOUGH ELEVATED SURFACES HAVE TO BE
WATCHED OUT THAT WAY. DUE TO LIMITED...IF ANY IMPACTS...WE DO NOT
PLAN ON ISSUING ANY ADVISORIES THROUGH TODAY AS THIS SHORTWAVE
LIFTS OUT READILY TO THE NORTHEAST AND TEMPERATURES REMAIN MOSTLY
STEADY STATE. WE WILL BE WATCHING FOR ANY POSSIBLE WET-BULB
EFFECTS HOWEVER TO THE NORTHWEST OF THE DFW METRO.
OTHERWISE...A FEW ELEVATED SHOWERS AND STORMS ABOVE THE FRONTAL
INVERSION ACROSS THE SOUTHEAST COUNTIES THROUGH THIS AFTERNOON.
CAN/T RULE OUT A LITTLE PEA HAIL WITH STRONGEST ACTIVITY. IT WILL
REMAIN MAINLY CLOUDY...WINDY AND COLD THROUGHOUT THE DAY WITH ONLY
A SLOW DROP IN TEMPS WITH CONTINUED CAA.
05/
&&
.AVIATION...
/ISSUED 553 AM CST SAT DEC 27 2014/
A COLD FRONT HAD MOVED THROUGH ALL TAF SITES AS OF 530 AM. THE
PASSAGE OF THE FRONT BROUGHT DRIER AIR AND LIFTING CEILINGS. MVFR
CONDITIONS WILL PREVAIL THROUGH SUNRISE WITH CEILINGS LIFTING
ABOVE 3000 FT BY MID TO LATE MORNING. SCATTERED LIGHT SHOWERS ARE
POSSIBLE THROUGH THE MORNING BUT THE BETTER RAIN CHANCES WILL
ARRIVE THIS AFTERNOON AS LARGE SCALE LIFT ASSOCIATED WITH A
APPROACHING UPPER TROUGH INCREASES. ANY SHOWERS THAT DEVELOP THIS
AFTERNOON WILL BE RELATIVELY LIGHT BUT MAY BE ACCOMPANIED BY MVFR
CEILINGS. A FEW SHOWERS COULD LINGER OVERNIGHT BUT COVERAGE WILL
BE TOO LIMITED TO INCLUDE IN THIS FORECAST. VFR CONDITIONS WILL PREVAIL
TONIGHT WITH SCATTERED TO BROKEN MIDDLE AND UPPER LEVEL CLOUDS.
A NORTH WIND WILL PREVAIL BETWEEN 16 AND 20 KNOTS TODAY WITH SOME
GUSTS UP TO ABOUT 27 KNOTS. WIND SPEEDS SHOULD FALL BELOW 15 KNOTS
BY MID EVENING.
79
&&
.PREV UPDATE...
HAVE UPDATED TO INCLUDE A RAIN/SLEET/SNOW MIX WEST OF A SHERMAN TO
WEATHERFORD TO COMANCHE LINE FOR THE REMAINDER OF THE DAY. RECENT
REPORTS FROM AREAS JUST WEST OF THE CWA INDICATE SOME LIGHT SNOW AND
SLEET IS OCCURRING. FORECAST SOUNDINGS...IN PARTICULAR THE
RAP...SUPPORT SOME LIGHT SNOW AND/OR SLEET MAY OCCUR WITH THE RAIN
TODAY ACROSS THE WEST AND NORTHWEST. VERY LITTLE SNOW OR SLEET
ACCUMULATIONS MAY OCCUR ON ELEVATED OR METAL SURFACES AND ROADWAYS
ARE EXPECTED TO REMAIN CLEAR OF ANY SNOW OR SLEET. ALSO ADJUSTED
POPS UP FOR THE MORNING HOURS BASED ON LATEST RADAR TRENDS. UPDATED
HOURLY TEMPERATURE FORECASTS AND WIND TRENDS FOR THE REMAINDER OF
THE DAY AS WELL USING THE LATEST RAP DATA. THE FRONT HAS JUST
ABOUT PUSHED THROUGH THE ENTIRE CWA AS OF 725 AM.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 43 32 50 33 58 / 60 20 5 5 5
WACO, TX 46 34 49 32 61 / 60 20 10 5 5
PARIS, TX 45 33 49 32 55 / 60 30 5 5 5
DENTON, TX 42 29 50 32 57 / 60 20 5 5 5
MCKINNEY, TX 43 31 49 32 57 / 60 20 5 5 5
DALLAS, TX 43 33 50 34 59 / 60 20 5 5 5
TERRELL, TX 45 34 50 32 58 / 60 30 5 5 5
CORSICANA, TX 47 35 49 33 60 / 60 30 10 5 5
TEMPLE, TX 46 34 49 32 61 / 50 20 20 5 5
MINERAL WELLS, TX 41 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
724 AM CST SAT DEC 27 2014
.UPDATE...
HAVE UPDATED TO INCLUDE A RAIN/SLEET/SNOW MIX WEST OF A SHERMAN TO
WEATHERFORD TO COMANCHE LINE FOR THE REMAINDER OF THE DAY. RECENT
REPORTS FROM AREAS JUST WEST OF THE CWA INDICATE SOME LIGHT SNOW AND
SLEET IS OCCURRING. FORECAST SOUNDINGS...IN PARTICULAR THE
RAP...SUPPORT SOME LIGHT SNOW AND/OR SLEET MAY OCCUR WITH THE RAIN
TODAY ACROSS THE WEST AND NORTHWEST. VERY LITTLE SNOW OR SLEET
ACCUMULATIONS MAY OCCUR ON ELEVATED OR METAL SURFACES AND ROADWAYS
ARE EXPECTED TO REMAIN CLEAR OF ANY SNOW OR SLEET. ALSO ADJUSTED
POPS UP FOR THE MORNING HOURS BASED ON LATEST RADAR TRENDS. UPDATED
HOURLY TEMPERATURE FORECASTS AND WIND TRENDS FOR THE REMAINDER OF
THE DAY AS WELL USING THE LATEST RAP DATA. THE FRONT HAS JUST
ABOUT PUSHED THROUGH THE ENTIRE CWA AS OF 725 AM.
82/JLD
&&
.AVIATION...
/ISSUED 553 AM CST SAT DEC 27 2014/
A COLD FRONT HAD MOVED THROUGH ALL TAF SITES AS OF 530 AM. THE
PASSAGE OF THE FRONT BROUGHT DRIER AIR AND LIFTING CEILINGS. MVFR
CONDITIONS WILL PREVAIL THROUGH SUNRISE WITH CEILINGS LIFTING
ABOVE 3000 FT BY MID TO LATE MORNING. SCATTERED LIGHT SHOWERS ARE
POSSIBLE THROUGH THE MORNING BUT THE BETTER RAIN CHANCES WILL
ARRIVE THIS AFTERNOON AS LARGE SCALE LIFT ASSOCIATED WITH A
APPROACHING UPPER TROUGH INCREASES. ANY SHOWERS THAT DEVELOP THIS
AFTERNOON WILL BE RELATIVELY LIGHT BUT MAY BE ACCOMPANIED BY MVFR
CEILINGS. A FEW SHOWERS COULD LINGER OVERNIGHT BUT COVERAGE WILL
BE TOO LIMITED TO INCLUDE IN THIS FORECAST. VFR CONDITIONS WILL PREVAIL
TONIGHT WITH SCATTERED TO BROKEN MIDDLE AND UPPER LEVEL CLOUDS.
A NORTH WIND WILL PREVAIL BETWEEN 16 AND 20 KNOTS TODAY WITH SOME
GUSTS UP TO ABOUT 27 KNOTS. WIND SPEEDS SHOULD FALL BELOW 15 KNOTS
BY MID EVENING.
79
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 45 32 50 33 58 / 60 20 5 5 5
WACO, TX 49 34 49 32 61 / 60 20 10 5 5
PARIS, TX 50 33 49 32 55 / 60 30 5 5 5
DENTON, TX 42 29 50 32 57 / 60 20 5 5 5
MCKINNEY, TX 45 31 49 32 57 / 60 20 5 5 5
DALLAS, TX 46 33 50 34 59 / 60 20 5 5 5
TERRELL, TX 52 34 50 32 58 / 60 30 5 5 5
CORSICANA, TX 54 35 49 33 60 / 60 30 10 5 5
TEMPLE, TX 51 34 49 32 61 / 50 20 20 5 5
MINERAL WELLS, TX 42 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/82
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1109 PM CST FRI DEC 26 2014
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
THE COLD FRONT OVER THE NORTHWESTERN PART OF THE STATE IS EXPECTED
TO REACH KCLL AND KUTS BY AROUND 13Z. LIKED A BIT FASTER PASSAGE
OF THE FRONT THAT EARLIER FORECASTED OVER THE REMAINING SITES AND
WENT MORE WITH THE LATEST RAP13 MODEL. THIS MEANS THE FRONT IS NOW
EXPECTED TO REACH KCXO BY 20Z...KIAH BY 21Z...AND KHOU BY 23Z. THE
FRONT SHOULD MAKE ITS WAY THROUGH KLBX AND KGLS BETWEEN 00Z AND
01Z. MVFR TO IFR CONDITIONS WILL DEVELOP AHEAD OF THE FRONT AND
SEA FOG FORMING SOUTH OF THE LOUISIANA COAST MAY WORK ITS WAY INTO
KGLS BY 14Z. IF SO...THE FOG WILL LIKELY LINGER IN PLACE UNTIL
SOUTHWESTERLY WINDS DEVELOP AROUND 20Z. THUNDERSTORMS ARE LIKELY
AHEAD OF THE FRONT AS IT MOVES INTO THE KCXO AND KIAH SITES
SOUTHWARD TO THE COAST.
BEHIND THE FRONT NORTHWESTERLY WINDS WILL DEVELOP...AND THEN
BECOME BREEZY BETWEEN 2 AND 4 HOURS LATER. ISENTROPIC LIFT WILL
LIKELY KEEP AT LEAST MVFR CONDITIONS IN PLACE BEHIND THE FRONT.
40
&&
.PREV DISCUSSION... /ISSUED 934 PM CST FRI DEC 26 2014/
UPDATE...
SEE DISCUSSION FOR EVENING UPDATE.
DISCUSSION...
ONLY MINOR CHANGES TO THE FORECAST THIS EVENING. COLD FRONT IS NOW
PAST LUBBOCK AND IS FORECASTED TO BE AT COLLEGE STATION AROUND 9
AM TOMORROW MORNING. THE FRONT IS THEN FORECASTED TO BE AT HOUSTON
BETWEEN 2 AND 4 PM. A CONVERGENCE ZONE HAS SET UP THIS EVENING
RIGHT AROUND THE COAST UP INTO HARRIS AND LIBERTY COUNTIES. HIGH
RES MODELS HAVE STRUGGLED WITH THIS PRECIP. NEW RAP SEEMS TO BE
CATCHING ON WITH THE CURRENT TRENDS. GENERAL THINKING IS FOR THE
PRECIP TO PUSH TOWARDS THE NORTH AND EXPAND IN COVERAGE AHEAD OF
THE FRONT. NEW 0Z LCH SOUNDING HAS A PRETTY GOOD CAP AROUND 700 MB
SO EXPECT MOST PRECIP TO REMAIN THUNDER FREE OVERNIGHT. GFS AND
NAM SOUNDINGS ERODE THE CAP A BIT AND SUPPORT THUNDER FOR THE
AFTERNOON. BEHIND THE FRONT EXPECT TEMPERATURES TO FALL TOMORROW.
23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 62 63 42 53 38 / 50 60 40 20 10
HOUSTON (IAH) 65 72 47 53 40 / 60 70 50 40 10
GALVESTON (GLS) 66 70 50 53 48 / 50 70 70 60 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 AM CST SATURDAY FOR
THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA
SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...23
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
344 AM EST MON DEC 29 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTH THROUGH THE AREA LATE THIS AFTERNOON
INTO TONIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY INTO
FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL
TROUGH WILL DEVELOP EARLY THIS WEEKEND THEN LIFT NORTH OF THE
REGION ON SUNDAY. A COLD FRONT FRONT WILL THEN PASS OFF THE COAST
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
...DIFFICULT FOG FORECAST THIS MORNING...
THROUGH MID-MORNING...DENSE FOG WILL REMAIN A CONCERN AS
WARM/MOIST AIR CONTINUES TO ADVECT NORTHWARD INTO THE REGION AHEAD
OF AN APPROACHING COLD FRONT. DENSE SEA FOG HAS ENCOMPASSED MUCH
OF CHARLESTON COUNTY AND IS BLEEDING INTO PORTIONS OF BERKELEY...
DORCHESTER AND COLLETON COUNTIES WHERE WIDESPREAD DENSE RADIATION
FOG IS ALSO OCCURRING. VISIBILITIES HAVE BEEN NEAR ZERO AT TIMES
PER SPOTTER AND COUNTY WARNING POINT REPORTS...BUT SOME
IMPROVEMENTS IN VISIBILITIES HAVE BEEN NOTED IN THE PAST 1-2 HOURS
AT A FEW SITES. IT IS UNCLEAR WHETHER THIS IS TEMPORARY IMPROVEMENT
OR THE BEGINNING OF A MORE DEFINITIVE TREND. WINDS HAVE INCREASED
TO AS HIGH AS 20 KT ATOP THE FOG LAYER PER KCLX VAD WIND PROFILE
DATA AND MAY BE HELPING TRANSITION SOME OF THE FOG INTO A VERY LOW
STRATUS DECK. RAP 1000 FT WINDS ARE PROGGED TO INCREASE TO 25-30
KT BY SUNRISE...SO THE FOG FORECAST IS CERTAINLY NOT CLEAR CUT.
FARTHER SOUTH...SATELLITE AND SURFACE OBSERVATIONS SHOW A LARGE
AREA OF SEA FOG AND LOW STRATUS WITH ORIGINS FROM THE NORTHEAST
GULF OF MEXICO IS POISED TO MOVE NORTH OF THE ALTAMAHA RIVER
THROUGH SUNRISE. VISIBILITIES MAY VERY WELL DROP BELOW 1/4 MILE
ACROSS PARTS OF SOUTHEAST GEORGIA AND THE REMAINDER OF SOUTHEAST
SOUTH CAROLINA OVER THE NEXT FEW HOURS AS SOME STRATUS BUILD DOWN
OCCURS. TRENDS ARE BEING WATCHED FOR A POSSIBLE EXPANSION OF THE
DENSE FOG ADVISORY. AGAIN...IT IS UNCLEAR HOW THE INCREASE IN 1000
FT WINDS WILL AFFECT THE FOG POTENTIAL IN THIS AREA.
SHOWER ACTIVITY ASSOCIATED WITH A WEAK AREA OF WARM AIR ADVECTION
AHEAD OF AN APPROACHING COLD FRONT WILL LARGELY REMAIN WEST OF THE
AREA THROUGH MID-MORNING.
REST OF TODAY...A WAVE FRONTAL WAVE AND COLD FRONT WILL DROP SOUTH
INTO THE AREA TODAY SHEAR SHORTWAVE ENERGY PASSES OFF TO THE
NORTH. DEEP MOISTURE COUPLED WITH ANAFRONTAL UPGLIDE AS WELL AS UVM
INDUCED BY THE RIGHT ENTRANCE REGION OF A 110 KT JET STREAK WILL
SUPPORT SCATTERED TO NUMEROUS SHOWERS THIS AFTERNOON. MODELS ARE
SIMILAR IN SHOWING LITTLE IN THE WAY OF MEASURABLE RAINFALL
THROUGH LATE MORNING WITH ACTIVITY BLOSSOMING OVER MUCH OF
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA DURING THE MID-LATE
AFTERNOON AS THE RIBBON OF STRONG JET DYNAMICS PASSES OVERHEAD.
WILL HIGHLIGHT LIKELY POPS TODAY OF 60-70 PERCENT. DESPITE THE
WARM TEMPERATURES...THE ATMOSPHERE LOOKS TOO MOIST AND STABLE TO
SUPPORT MUCH OF THE WAY OF THUNDER FOR MUCH OF THE DAY. THE ONLY
EXCEPTION WOULD BE IN A NARROW CORRIDOR JUST AHEAD OF THE COLD
FRONT FROM ROUGHLY LUDOWICI TO SAVANNAH...HILTON HEAD AND POINTS
SOUTH WHERE NAM12/GFS BOUNDARY LAYER LIFTED INDEX AND 850 HPA
SHOWALTER FIELDS SUGGEST THERE MAY BE JUST ENOUGH SURFACE AND
ELEVATED INSTABILITY TO SUPPORT AN ISOLATED TSTM OR TWO. HIGHS
WILL RANGE FROM THE MID 60S WELL INLAND TO THE UPPER 60S TO LOWER
70S ACROSS THE COASTAL COUNTIES WITH A FEW MID 70S ACROSS MCINTOSH
COUNTY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
TONIGHT...THE WEAK COLD FRONT WILL DROP SOUTH THROUGH THE AREA
OVERNIGHT. THE BEST CHANCE FOR RAIN WILL OCCUR THIS EVENING AS THE
LAST OF THE SHEARED SHORTWAVE ENERGY PASSES OFFSHORE AND TO THE
NORTH. THE PRIMARY FRONTAL BAND RAIN ACTIVITY WILL GRADUALLY
DISSIPATE WITH TIME AS THE FRONT SHIFTS SOUTH AND OFFSHORE. WILL
CARRY 50-70 PERCENT POPS DURING THE EVENING HOURS...HIGHEST ACROSS
THE COASTAL COUNTIES...WITH POPS STEADILY DIMINISHING THROUGH THE
NIGHT AS THE FRONT CLEARS THE AREA AND MID-LEVEL DRY AIR
ADVECTS IN FROM THE SOUTHWEST. LOWS WILL RANGE UPPER 40S WELL
INLAND TO THE UPPER 50S ALONG THE GEORGIA COAST.
TUESDAY...THE COLD FRONT IS EXPECTED TO BE OFFSHORE EXTENDING BACK
INTO NE FLORIDA DURING THE MORNING. THERE COULD BE AREAS OF LOW
CLOUDS IN THE FRONTAL TROUGH BEFORE STRATOCUMULUS EXPAND DURING
THE DAY. MODELS INDICATE A FAST MAINLY ZONAL FLOW ALOFT WITH A
BUCKLED SURFACE PATTERN TO THE LEE OF THE MOUNTAINS AS COLD AIR
ADVECTION BUILDS ACROSS THE CAROLINAS. WEAK DOWNSLOPE AND SLOWER LOW
LEVEL COLD AIR ADVECTION PATTERN IN SE GEORGIA SUGGEST MILDER TEMPS
WITH SOME AFTERNOON CLEARING POSSIBLE. TO THE NORTH...WE MAINTAINED
PLENTY OF CLOUDS ACROSS SOUTH CAROLINA AND KEEP POPS SILENT. SOME
UPPER FORCING MAY LEAD TO A FEW SPRINKLES NORTHERN ZONES BUT THE
DEEPER LAYERS LOOK TOO DRY TO KEEP ANY LINGERING POPS. WE LOWERED
HIGH TEMPS OVER FAR NORTHERN ZONES DUE THE EXPANSIVE CLOUDS AND
COLDER BOUNDARY LAYER TEMPS.
AN IMPRESSIVELY STRONG AND EXPANSIVE SURFACE HIGH WILL STRETCH
ACROSS MUCH OF THE CENTRAL AND EASTERN UNITED STATES WEDNESDAY
AND THURSDAY. EXPECT RATHER QUIET CONDITIONS TO PREVAIL...WITH
TEMPERATURES NOT FAR FROM SEASONAL NORMAL. HIGH TEMPERATURES WILL
BE IN THE MID 50S NORTH TO NEAR 60 DEGREES SOUTH UNDER MOSTLY CLEAR
TO PARTY CLOUDY SKIES. BOTH WEDNESDAY AND THURSDAY MORNING WILL
FEATURE LOWS IN THE LOWER TO 30S INLAND TO UPPER 30S TO NEAR 40
ALONG THE U.S. 17 CORRIDOR.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE EXPANSIVE SURFACE HIGH WILL STEADILY SHIFT OVER GEORGIA AND
THE CAROLINAS BY FRIDAY...BEFORE MOVING INTO THE ATLANTIC WATERS
SATURDAY. A STRONG CUT OFF LOW OVER THE DESERT SOUTHWEST FRIDAY WILL
EJECT INTO THE SOUTHERN PLAINS OVER THE WEEKEND AND THEN DAMPEN
AS IT MOVE INTO THE UPPER GULF COAST REGION BY LATE WEEKEND. CLOUDS
WILL BE ON THE INCREASE THURSDAY NIGHT AS A SHORT WAVES TRAVERSES
INTO THE REGION ATOP A LARGE SUBTROPICAL RIDGE OVER FLORIDA AND
THE CARIBBEAN. THIS DISTURBANCE MAY PRODUCE SOME SPOTTY LIGHT RAINS
ON FRIDAY BUT CERTAINLY NOT SIGNIFICANT AS PRECIP IS LIKELY TO
EVAPORATE IN DRY LAYERS BELOW 10 KFT. A SLIGHT CHANCE POP LOOKS QUITE
SUFFICIENT. STEADIER RAINS ACROSS NORTH GEORGIA AND THE WESTERN
CAROLINAS MAY BEGIN TO ANCHOR A WEDGE ON SATURDAY WITH GLOBAL
MODELS DIFFERING ON SURFACE PATTERNS. THE WEEKEND LOOKS A BIT
UNSETTLED WITH PLENTY OF CLOUDS MOST AREAS AND MAINLY LOW END CHANCE
POPS AS THE UPPER WAVE FLATTENS SIGNIFICANTLY LATE IN THE WEEKEND.
SUNDAY APPEARS TO BE THE WARMER OF THE DAYS AFTER WE TRENDED DOWN A
GOOD BIT ON TEMPS NORTHERN ZONES SATURDAY. A COLD FRONT SHOULD MOVE
OFF THE COAST EARLY NEXT WEEK.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
KCHS..VSBYS ARE STEADILY LOWERING AS A COMBINATION OF RADIATION
FOG AND POSSIBLY SEA FOG AFFECTS THE TERMINAL. EXPECT CONDITIONS
TO DROP BELOW AIRPORT MINIMUMS SOON WITH VSBYS DROPPING TO 1/4SM
VV001 AND STAYING THERE THROUGH ABOUT 13-14Z. THERE MAY BE SOME
VARIABLE VSBYS THROUGH ABOUT 08Z...BUT SHOULD SETTLE WELL INTO
LIFR AFTER THAT. CONDITIONS WILL IMPROVE TO MVFR 14-16Z AND REMAIN
THERE THROUGH SUNSET. LIGHT RAIN WILL LIKELY IMPACT THE TERMINAL
21-02Z AS A COLD FRONT DROPS SOUTH. VSBYS WILL BE LIMITED TO MVFR
FOR NOW...ALTHOUGH PERIODS OF IFR ARE POSSIBLE IN POCKETS OF
HEAVIER RAINFALL. LOW CLOUDS WILL FILL BACK IN BEHIND THE FRONT
WITH IFR CIGS.
KSAV...DIFFICULT FOG FCST FOR THE TERMINAL WITH HIGH RESOLUTION
MODELS OFFERING A NUMBER OF POSSIBLE OUTCOMES. WILL CONTINUE TO
STAY SOMEWHAT CONSERVATIVE UNTIL MORE PESSIMISTIC TRENDS BECOME
APPARENT...BUT IT IS CERTAINLY POSSIBLE CONDITIONS COULD DROP BELOW
ALTERNATE MINIMUMS AND EVEN AIRPORT MINIMUMS PRIOR TO SUNRISE. FOR
NOW WILL LIMIT CONDITIONS TO 2SM BR OVC006...OR JUST ABOVE
AIRFIELD MINIMUMS. AMENDMENTS WILL BE ISSUED AS NEEDED. EXPECT MVFR
CONDITIONS TO RETURN BY 14Z. LIGHT RAIN WILL OVERSPREAD THE
TERMINAL BY 20Z AND LINGER THROUGH 03Z AS A COLD FRONT DROPS
SOUTH. EXPECT IFR CIGS TO FILL IN BEHIND THE FRONT.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE LIKELY LATE
TONIGHT AS A COLD FRONT MOVES ACROSS THE REGION. MVFR CIGS
POSSIBLE INTO THE DAY TUESDAY IN THE WAKE OF THE FRONT...VFR
CONDITIONS RETURN TUESDAY NIGHT INTO LATE WEEK.
&&
.MARINE...
TODAY...DENSE SEA FOG WILL LINGER OR MUCH OF THE DAY ACROSS THE
COASTAL WATERS. THE FOG WILL LIKELY RETREAT A BIT THROUGH THE DAY
INTO THE CORRIDOR OF COLDEST WATER LOCATION FROM THE BEACHES TO
ABOUT 5-8 NM OFFSHORE. WILL MAINTAIN THE MARINE DENSE FOG
ADVISORY FOR ALL LEGS EXCEPT THE GEORGIA OFFSHORE WATERS THROUGH
10 AM. OTHERWISE...SW WINDS AROUND 10 KT WILL PERSIST WITH
COMBINED SEAS AVERAGING 2-3 FT NEARSHORE AND 3-4 FT OFFSHORE.
TONIGHT...THE RISK FOR SEA FOG WILL LINGER THROUGH THIS EVENING
OVER THE SOUTH CAROLINA WATERS AND LATE TONIGHT FOR THE GEORGIA
NEARSHORE WATERS AS A COLD FRONT DROPS SOUTH. AS WINDS TURN NORTH
ANY SEA FOG COULD BE PUSHES TO THE SOUTH AND OFFSHORE. SW WINDS
5-10 KT WILL PREVAIL AHEAD OF THE FRONT...THEN TURNING NORTH 10 KT
WITH ITS PASSAGE. SEAS WILL 2-3 FT WILL SUBSIDE TO 1-2 FT OVER THE
NEARSHORE WATERS WITH 3-4 FT SEAS SUBSIDING TO 2-3 FT FOR THE
GEORGIA OFFSHORE LEG.
TUESDAY THROUGH FRIDAY...HIGH PRES WILL BUILD FROM THE NORTHWEST
MID WEEK AND RESIDE OVER THE WATERS BY FRIDAY. COOLER AND QUITE A
BIT DRIER AIR MOVING IN WILL SET UP SOME TIGHT THERMAL AND
MOISTURE GRADIENT TUESDAY NIGHT INTO WEDNESDAY NIGHT RESULTING IN
SOME OCCASIONAL SURGES FROM THE NORTH AND NORTHEAST. 15-20 KT FLOW
OVER THE GEORGIA WATERS ON WEDNESDAY SHOULD RESULT IN SEAS
BUILDING TO 4-6 FT BEYOND 20 NM OFFSHORE. SMALL CRAFT ADVISORY
CONDITIONS ARE POSSIBLE DURING THIS TIME. LIGHTER WINDS BY LATE
WEEK WITH WINDS AND SEAS BELOW ANY CRITERIA THRESHOLDS. A BIT TOO
EARLY TO COMMIT ON STRENGTH OF THE WEDGE THIS WEEKEND AND TIMING
THE WARM FRONT THROUGH...BUT COMPLEX LOW LEVEL MIXING ENVIRONMENTS
ARE LIKELY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ043>045-
050-052.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330-350-
352-354.
&&
$$
ST/RVT
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
308 AM CST Mon Dec 29 2014
.SHORT TERM...(Today)
ISSUED AT 308 AM CST MON DEC 29 2014
08z/2am surface analysis shows strong 1057mb high over northern
British Columbia/Alberta. Bitterly cold airmass beneath the high
with current temps in the teens and 20s below zero is building
southward into the Northern Plains/Upper Midwest, with the leading
edge of the colder air sinking toward northern Illinois. Front will
remain north of the KILX CWA today: however, increasing mid/high
clouds in the vicinity of the boundary will be noted across the
north. End result will be partly to mostly cloudy skies north of
Peoria, with mostly sunny skies further south across the remainder
of the area. High temperatures will once again be near normal for
this time of year in the middle to upper 30s.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 308 AM CST MON DEC 29 2014
Main weather story this week will be the shot of very cold air
expected Tuesday through Thursday. Arctic cold front will settle
southward into central Illinois tonight, accompanied by clouds and
perhaps a few flurries. NAM time-height cross-sections show much
shallower moisture profiles and weaker lift than they did on
previous runs: however, think strong CAA will still be enough to
produce scattered flurries overnight. Any flurries will come to
an end Tuesday morning as high pressure builds into the region and
skies gradually clear. High temperatures will be much colder than
today, ranging from the lower 20s northwest to the lower 30s south
of I-70. Heart of the coldest airmass will arrive Tuesday night
into Wednesday. Thanks to clear skies and diminishing winds, low
temperatures Tuesday night will bottom out in the single digits
and teens, with corresponding wind-chill readings dropping below
zero. Despite full sunshine, highs on Wednesday will struggle to
reach the lower to middle 20s. As high pressure sinks south of
the region, winds will back to the southwest and help boost temps
back into the lower 30s by Thursday.
Forecast becomes more complicated later in the week, as a southern
stream system slowly approaches from the southwest. Model-to-model
as well as run-to-run consistency remains poor, so forecast
confidence beyond Thursday is low. Latest trend observed with the
00z Dec 29 model suite suggests a deeper cut-off low over the Desert
Southwest and thus a slower northeastward ejection. Current water
vapor imagery shows a strong jet streak diving southward along the
West Coast, which is progged to carve out a closed upper low over
California within the next 48 hours. Models are in very good
agreement initially, showing the low meandering slowly eastward to
the Texas/Oklahoma panhandles by Saturday evening: however, they
have very different ideas on how to handle precip ahead of the
system. The ECMWF shows precip breaking out well in advance of
the low across the southern Plains Thursday, then spreading
northeastward into south-central Illinois and the Ohio River
Valley late Thursday night into Friday. Given presence of
cold/dry airmass across the region, am very skeptical about this
aggressive push of precip. As a result, will continue with a dry
forecast Thursday night and will reduce PoPs significantly during
the day Friday. The GFS seems to have a much more realistic
solution, showing precip remaining south of Illinois until Friday
night into Saturday. Models are in poor agreement with what
happens to the southwest system over the weekend, with the ECMWF
maintaining a closed 500mb low longer than the GFS, which opens
the wave and allows it to be absorbed into the northern stream
much faster. If the ECMWF verifies, much of the precip associated
with the low will remain southeast of Illinois across the Ohio
River Valley. This is a drastic change from its previous runs, so
am looking at this with a great deal of skepticism. Prefer the
more consistent GFS, which opens the low and brings it northward
into the area on Saturday. As a result, have introduced chance
PoPs across the board Friday night/Saturday, then have ended
precip chances by Sunday as the system exits into the Great Lakes.
Precip type will be an issue as well, with forecast soundings and
surface temps initially supporting snow or a rain/snow mix.
Atmosphere will likely warm enough to change the precip to mostly
rain on Saturday before colder air returns Saturday night into
Sunday. Overall this does not look like a major winter storm for
central Illinois, but future model runs will need to be monitored
for any potential changes.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1146 PM CST SUN DEC 28 2014
High pressure centered across our counties will keep VFR
conditions in general. Some fog is indicated in the HRRR and RAP
models along the ridge axis for CMI and DEC. The RAP goes all the
way to VLIFR with the fog across CMI/DEC/SPI, while the HRRR keeps
the LIFR fog east of CMI. Will add MVFR fog at CMI and DEC as
light fog is developing along that axis already near-by.
A weak cold front extending from SE Nebraska to southern Michigan
will slowly drift to the southeast over the next day. As the cold
front approaches Monday evening, MVFR clouds are expected to
arrive from NW to SE.
The increasing clouds will be triggered by a shortwave moving
east along the front as it arrives in the area. A few flurries
could develop for the northern terminals of PIA and BMI. Models
have trended drier with the last 2 runs, so do not expect any snow
accumulation as the NAM was suggesting previously. Will add -sn at
PIA and BMI Monday evening, and keep the other TAF sites dry.
Winds will remain calm under the surface ridge axis tonight. A
northeast wind will develop by mid-morning on Monday and continue
through the rest of the TAF period. Wind speeds will remain less
than 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 PM CST SUN DEC 28 2014
.SHORT TERM...
346 PM CST
REMAINDER OF THIS AFTERNOON AND TONIGHT...
QUIET WEATHER WILL CONTINUE THROUGH THE REMAINDER OF THIS AFTERNOON
AND TONIGHT WITH CLEAR SKIES OVER MUCH OF THE CWA. THE ONLY CLOUD
COVER OF SIGNIFICANT IS A LAYER OF DENSE CIRRUS OVER NWRN INDIANA
AND EAST-CENTRAL IL ASSOCIATED WITH THE SUBTROPICAL JET STREAM
EXTENDING FROM THE WRN GLFMEX THROUGH NEW ENGLAND. AS SFC HIGH
PRESSURE CONTINUES TO SPREAD SOUTHEAST TOWARD THE OHIO VALLEY...ALL
CLOUD COVER SHOULD MOVE OUT OF THE AREA AND CLEAR SKIES SHOULD
PREVAIL ACROSS THE REGION TONIGHT. THE AMPLE SUNSHINE HAS SLIGHTLY
COUNTERED THE PERSISTENT COLD ADVECTION ACROSS THE REGION...ALLOWING
TEMPERATURES TO TOP OUT IN THE LOWER 30S THIS AFTERNOON. WHILE
WINDS ARE EXPECTED TO DROP OFF OVERNIGHT WITH THE BUILDING HIGH
PRESSURE...DIRECTION SHOULD VEER A BIT MORE NELY...SETTING UP A
FETCH OFF OF LAKE MICHIGAN...SO SFC DEWPOINTS SHOULD REMAIN IN THE
UPPER TEENS TO LOWER 20S...WITH THE VERY DRY AIR CURRENTLY OVER THE
UPPER MISSISSIPPI VALLEY WITH SFC DEWPOINTS IN THE SINGLE DIGITS
ABOVE 0F TO THE SINGLE DIGITS BELOW 0F REMAINING TO THE NORTH AND
WEST OF THE CWA...LIMITING THE RADIATIVE COOLING. SO...ONLY EXPECT
THAT TEMPS SHOULD DROP INTO THE LOWER TO MIDDLE 20S ACROSS THE
AREA...WITH UPPER 20S TEMPS NEAR THE LAKE.
KREIN
&&
.LONG TERM...
346 PM CST
MONDAY THROUGH SUNDAY...
THE NEXT WEATHER OF CONCERN WILL BE THE CHANCES FOR LAKE EFFECT SNOW
ACROSS NERN IL AND NWRN IN. AS THE SFC HIGH BUILDS ACROSS THE
REGION...LOW LEVEL WINDS WILL INITIALLY BE NELY MONDAY MORNING.
MODEL SOUNDINGS INDICATE AT LEAST SOME WEAK INSTABILITY OVER THE SRN
END OF THE LAKE...WHICH WOULD BE CONDUCIVE TO LAKE EFFECT SNOW
SPREADING INLAND BEGINNING EARLY MONDAY MORNING. LOW LEVEL FLOW
WILL GRADUALLY BACK FROM NELY...THROUGH NLY MONDAY NIGHT AND THEN
NWLY BY TUESDAY MORNING. EQUILIBRIUM HEIGHTS THROUGH THE PERIOD
WILL RANGE FROM ARND 4KFT-6KT WITH LAKE INDUCED CAPE OF ARND
300-400J/KG...SO SOME LAKE EFFECT SNOW WILL BE LIKELY...BUT
ANTICIPATE THAT THE GREATEST CHANCES FOR ACCUMULATING SNOW WILL BE
RELATIVELY CLOSE TO THE LAKE...WITH ONLY SCT -SHSN OR FLURRIES
FARTHER INLAND INTO THE CHICAGO METRO AREA. ALSO...WITH LOW LEVEL
FLOW SLOWLY...BUT CONTINUOUSLY BACKING FROM NELY TO NWLY FROM MONDAY
MORNING THROUGH TUESDAY MORNING...DO NOT ANTICIPATE THAT ANY SINGLE
LAKE PLUME...SHOULD ONE DEVELOP...TO REMAIN OVER ANY GIVEN AREA FOR
A SIGNIFICANT AMOUNT OF TIME...SO WOULD ANTICIPATE THAT ANY
ACCUMULATIONS WOULD BE BELOW ADVISORY CRITERIA. LATEST INDICATORS
SUGGEST THAT THE COOK COUNTY LAKEFRONT...INCLUDING DOWNTOWN CHICAGO
COULD SEE 1 TO 3 INCHES TOTAL SNOWFALL...WHILE NWRN INDIANA MAY SEE
2 TO 4 INCHES. HOWEVER...THESE AMOUNTS WILL BE HIGHLY DEPENDENT ON
SFC FETCH AND HOW QUICKLY SFC WINDS WILL BACK FROM NELY TO NWLY...SO
THERE IS STILL SOME UNCERTAINTY IN THE SNOWFALL AMOUNTS. HAVE
BETTER CONFIDENCE IN GENERAL THAT ACCUMULATING SNOW WILL BE CONFINED
TO LOCATIONS NEAR THE LAKE AND THAT ANY SNOW OBSERVED FARTHER INLAND
WILL BE CLOSER TO A DUSTING. BY TUESDAY AFTERNOON...LOW LEVEL WINDS
SHOULD VEER FAR ENOUGH THAT ANY LAKE EFFECT SNOW SHOULD BE OUT OF
THE CWA...WITH THE POSSIBLE EXCEPTION OF FAR NERN PORTER COUNTY.
TEMPERATURES FOR MONDAY SHOULD RANGE FROM THE UPPER 20S TO AROUND 30
ALONG THE WISCONSIN BORDER TO THE MIDDLE 30S SOUTH OF I-80. THE
MORE SIGNIFICANT COOLING TREND WILL BEGIN MONDAY NIGHT AS THE ARCTIC
HIGH PRESSURE SPREADS ACROSS THE AREA AND INTO THE OHIO VALLEY AND
THROUGH THE LOWER MISSISSIPPI VALLEY. BY TUESDAY
MORNING...ANTICIPATE LOW TO RANGE FROM THE LOWER TEENS OVER THE
ROCKFORD AREA TO THE LOWER 20S EAST OF THE I-55 CORRIDOR.
PERSISTENT COLD ADVECTION WILL KEEP HIGHS ON TUESDAY AND WEDNESDAY
IN THE MIDDLE TO UPPER TEENS. THE LOWEST TEMPS SHOULD OCCUR
WEDNESDAY MORNING WITH MUCH OF THE CWA SEEING TEMPS DROP INTO THE
SINGLE DIGITS ABOVE 0F OVER NRN IL AND 10-13F OVER NWRN INDIANA.
WITH WINDS REMAINING AROUND 10 MPH THROUGH THE NIGHT...MIN WIND
CHILL READINGS TUESDAY MORNING SHOULD DROP TO AROUND -5F TO -10F.
SOME MODERATION IS EXPECTED FOR LATER IN THE WEEK...BUT TEMPERATURES
SHOULD REMAIN AROUND SEASONAL NORMAL LEVELS. THE NEXT QUESTION FOR
THE EXTENDED FORECAST PERIOD WILL FOCUS ON THE EVOLUTION OF A STRONG
PACIFIC SHORTWAVE DROPPING DOWN THE WEST COAST AND CLOSING OFF OVER
THE DESERT SOUTHWEST WEDNESDAY NIGHT AND THURSDAY. THE DIGGING
TROUGH OVER THE WEST SHOULD INITIATE SOME HEIGHT RISES OVER THE
MIDWEST...WHICH WILL HELP WITH THE MODERATING TEMPERATURES IN SPITE
OF PERSISTENT NWLY FLOW ALOFT AS BROAD LOW AMPLITUDE TROUGHING
DEVELOPS OVER THE NCNTRL/NERN CONUS WHILE AN UPPER HIGH PARKS OVER
THE GREATER ANTILLES AND WRN CARIBBEAN. THE FORECAST CONCERNS WILL
FOCUS ON HOW QUICKLY THE UPPER LOW WILL LIFT OUT OF THE DESERT
SOUTHWEST WITH SRN STREAM ENERGY LIFTING THROUGH THE SRN PLAINS
AND...ULTIMATELY INTO THE SRN GREAT LAKES...AND HOW MUCH PHASING
WILL OCCUR WITH NRN STREAM ENERGY. THE 12Z GFS IS STILL TRENDING
MUCH QUICKER THAN THE OTHER LONGER RANGE GUIDANCE WITH THE 12Z ECMWF
ADVERTISING THE SLOWEST SOLUTION AND THE GEM TAKING A MIDDLE OF THE
ROAD SOLUTION. STILL FAVOR A SLOWER SOLUTION FOR A SRN STREAM
CUT-OFF AS THE MODELS ARE NOTORIOUS FOR BEING TOO FAST IN LIFTING
THESE SYSTEM NEWD. THE GENERAL TREND FOR THE LATTER PORTIONS OF THE
EXTENDED FORECAST PERIOD SHOULD BE FOR INCREASING TEMPERATURES AND
POPS BY THE END OF THE WEEK AND INTO THE WEEKEND...BUT CONFIDENCE IS
STILL LOW ON THE EXACT DETAILS OF ANY ASSOCIATED PCPN. TEMPERATURES
THROUGH THEN PERIOD SHOULD GENERALLY BE LOW ENOUGH TO SUPPORT SOME
SNOW...BUT THERE COULD ALSO BE PERIODS WHERE TEMPS COULD BE HIGH
ENOUGH FOR SOME OF THE PCPN TO BE EITHER RAIN OR A RAIN-SNOW MIX.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS DEVELOPING OVERNIGHT...AND CONTINUING AT TIMES MONDAY.
* LAKE EFFECT FLURRIES MONDAY AND MONDAY EVENING.
* NORTH/NORTHEAST WINDS APPROACHING 10KT MONDAY AFTERNOON.
KMD
//DISCUSSION...UPDATED 06Z...
MVFR CIGS OVER SOUTHERN WI WILL MOVE SOUTH DURING THE EARLY
MORNING HOURS LIKELY SPREADING INTO NORTHERN ILLNOIS IN THE COMING
HOURS. MEANWHILE...ADDITIONAL LOW CLOUDS OVER THE LAKE WILL
SPREAD INTO NE ILLINOIS TOWARD DAYBREAK WITH MVFR CIGS CONTINUING
MONDAY. LOW- MEDIUM CONFIDENCE REGARDING HOW SOON THESE CIGS WILL
ARRIVE BUT ONCE THEY DO...EXPECT THEM TO LINGER THROUGH THE
MORNING...AND THROUGH THE AFTERNOON CLOSE TO THE LAKEFRONT. NE
WINDS LOOK TO GET AROUND 10 KT THIS AFTERNOON WITH THESE LOWER
CIGS IN PLACE.
AS COLDER AIRSPREADS ACROSS THE AREA...LAKE EFFECT FLURRIES OR
SNOW SHOWERS ARE POSSIBLE MONDAY INTO MONDAY NIGHT. HRRR/RAP
SUGGEST A PERIOD OF FLURRIES OR LIGHT SNOW SHOWERS THIS MORNING
AFTER 13Z AS THE LEADING EDGE OF COLDER AIR SPREADS SOUTH...POSSIBLY
LASTING OFF AN ON FOR SEVERAL HOURS. NO ACCUMULATIONS ARE EXPECTED
UNLESS A SHOWER COMES RIGHT OVER A TERMINAL. ALLL OF THIS IS EAST
OF RFD/DPA. MAINTAINED A PROB30 FOR SHOWER ACTIVITY AND WILL
MONITOR AS THINGS MATERIALIZE OR NOT LATER THIS MORNING. THEN
THERE APPEARS TO BE A LULL IN ANYTHING MORE THAN LAKE CLOUDS. BEST
CHANCES FOR LAKE EFFECT SNOW SHOWERS AT GYY COULD BE MONDAY
EVENING.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH FOR MVFR CIGS...MEDIUM FOR TIMING.
* MEDIUM FOR LAKE EFFECT FLURRIES MONDAY/MONDAY EVENING.
* MEDIUM FOR WINDS THRU THE PERIOD.
KMD
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
* TUESDAY...DRY. MVFR CIGS POSSIBLE. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY WESTERLY WINDS.
* FRIDAY...CHANCE OF SNOW. MVFR POSSIBLE. SOUTH/SOUTHEAST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE. SOUTH WINDS
BECOMING WEST.
&&
.MARINE...
326 PM CST
LIGHTER SPEEDS HAVE BEEN OBSERVED OVER THE LAKE TODAY...WHILE A
NORTHWEST DIRECTION PREVAILED. A LINGERING TROUGH OF LOW PRESSURE
OVER SOUTHEAST ONTARIO IS HELPING FOR SLIGHTLY HIGHER SPEEDS OVER
THE NORTHERN HALF OF THE LAKE WHERE 15 TO 25 KT WINDS CONTINUE TO
BE OBSERVED...WITH 10 TO 20 KT BEING OBSERVED OVER THE SOUTHERN
HALF. THIS WILL LIKELY CONTINUE TONIGHT AS A FRONT PUSHES SOUTH
DOWN THE LAKE...AND THEN AS HIGH PRESSURE BUILDS SOUTHEAST THROUGH
THE UPPER MIDWEST AND GREAT LAKES. THIS HIGH WILL THEN CONTINUE TO
BUILD SOUTHEAST ON MONDAY...WITH THE CENTER OF THE STRONG HIGH
BUILDING SOUTH ACROSS THE PLAINS TUESDAY INTO WEDNESDAY. THIS WILL
HELP WITH A NORTH TO NORTHWEST WIND TO REMAIN IN PLACE DURING THIS
PERIOD...BEFORE WINDS TURN MORE WESTERLY TUESDAY NIGHT INTO
WEDNESDAY. EXPECT WINDS TO SIGNIFICANTLY INCREASE DURING THE DAY
WEDNESDAY WITH GALES APPEARING TO BE LIKELY...AS THE STRONG HIGH
REMAINS TO THE SOUTHWEST AND DEVELOPING LOW PRESSURE MOVES SOUTH
THROUGH HUDSON BAY.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1146 PM CST Sun Dec 28 2014
.UPDATE...
ISSUED AT 900 PM CST SUN DEC 28 2014
Clear skies early this evening allowed temps to drop off quickly
toward overnight lows. Some cirrus streaming into the NW half of
our forecast area will help to slow down the temp falls the rest
of the night. Still expect a few more degrees of temp drop under
those clouds, and another 3-5 deg where skies remain clear. Temps
are approaching the dewpoints already, which will also work to
slow additional temp falls. However, still decided to trim a few
degrees from lows in most areas, with higher changes toward
Danville.
Winds will remain light and variable under the surface ridge axis,
extending across Illinois from northeast Oklahoma to northwest
Indiana. The remainder of the forecast looks on track with no
weather makers until possibly Monday night when flurries develop
with the next shortwave. Updated info will be available shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 310 PM CST SUN DEC 28 2014
High pressure briefly building into the region this evening as
clouds slowly erode and move off to the southeast. Colder air
moving in with clearing skies tonight will drop overnight lows a few
more degrees from last nights lows. With the ridge axis moving into
the region, the winds become light and variable in the overnight,
allowing for more efficient radiational cooling in addition to the
colder airmass. Other than the cold start to the morning, weather
tonight rather quiet for the Midwest.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 310 PM CST SUN DEC 28 2014
As the high pressure shifts to the southeast, a larger, colder high
pressure area will slide in with Arctic air. There will be a thin
boundary between the two air masses and with this, there will be a
small chance of flurries as it passes. Timing of this feature looks
to be Monday night and Tuesday morning. This colder Arctic high will
bring well below normal temps to the region for Tue night through
Wed night. The coldest lows are expected to be Tue night and the
coldest highs on Wed. Breezy northwest winds during the period will
also create wind chills below zero across the northern part of the
state, especially Tue night and Wed morning.
This high pressure will dominate the weather through Thur night and
will slide into the eastern US by Thur evening. With this high to
the east and an upper level low in the southwest US, moisture and
warmer temps will begin to advect back northward into the region.
Model differ on the timing of this return flow and this results in
differences in timing of the return of pcpn to the area. The ECMWF
is quicker and further east with the track of a low pressure area,
along with the associated pcpn. The GFS is slower and further west
to northwest with the track, and thereby brings more warm air into
the region ahead of the low pressure area, and more pcpn. Looks like
the regional blend leans toward the GFS with a western track, more
warm air ahead of the system and more of a spread of pcpn over the
area. The next question then, is what will p-type be during the
period. Due to the spread of the models, confidence is low, so will
keep p-type simple and just go with snow becoming rain or snow, and
then just rain, and then back to rain or snow. 850mb temps look to
be couple of degrees above freezing, so would expect rain well north
into the cwa. However, the question is the sfc temps. Anywhere with
temps below freezing has the potential of receiving freezing rain.
But if the rain is heavy enough, then temps could remain at or just
above freezing overnight Friday. To repeat, forecast confidence is
low due to model spread, so will not be adding any freezing pcpn at
this time. As the system gets closer and the models reach some
agreement and consistency, forecast changes are likely. Beyond this
system, dry and cooler temps are again expected for Sat night and
Sunday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1146 PM CST SUN DEC 28 2014
High pressure centered across our counties will keep VFR
conditions in general. Some fog is indicated in the HRRR and RAP
models along the ridge axis for CMI and DEC. The RAP goes all the
way to VLIFR with the fog across CMI/DEC/SPI, while the HRRR keeps
the LIFR fog east of CMI. Will add MVFR fog at CMI and DEC as
light fog is developing along that axis already near-by.
A weak cold front extending from SE Nebraska to southern Michigan
will slowly drift to the southeast over the next day. As the cold
front approaches Monday evening, MVFR clouds are expected to
arrive from NW to SE.
The increasing clouds will be triggered by a shortwave moving
east along the front as it arrives in the area. A few flurries
could develop for the northern terminals of PIA and BMI. Models
have trended drier with the last 2 runs, so do not expect any snow
accumulation as the NAM was suggesting previously. Will add -sn at
PIA and BMI Monday evening, and keep the other TAF sites dry.
Winds will remain calm under the surface ridge axis tonight. A
northeast wind will develop by mid-morning on Monday and continue
through the rest of the TAF period. Wind speeds will remain less
than 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...Auten
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS JACKSON KY
348 AM EST MON DEC 29 2014
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 100 AM EST MON DEC 29 2014
FRONTAL BOUNDARY HAS MOVED SOUTH OF THE REGION TONIGHT WITH SURFACE
LOW RIDING UP ACROSS THE CAROLINA/TENNESSEE BORDER INDICATED BY 03Z
SURFACE ANALYSIS. MOST OF THE HEAVIER RAIN SHOWER ACTIVITY HAS MOVED
SOUTH OF THE REGION TONIGHT...HOWEVER DRIZZLE OR ISOLATED SHOWERS
WILL BE POSSIBLE OVERNIGHT. TAF SITES HAVE BEEN FLUCTUATING TONIGHT
WITH MOST SITES SEEING IFR TO LIFR CONDITIONS. SOME DRIER AIR HAS
BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE CWA WITH SYM CIGS
MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE AT MOST SITES AND
COULD BRING LOWER CONDITIONS TO THESE SITES THAT SEE THE HIGHER CIGS.
MOVING INTO TOMORROW MORNING WOULD EXPECT SOME IMPROVEMENTS TO THE
TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES ARE ONLY EXPECTED TO
IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO TOMORROW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
218 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 218 AM EST MON DEC 29 2014
THIS EVENING WE ARE SEEING A AREA OF RAIN AND DRIZZLE MOVING NE
ACROSS THE SW PORTIONS OF THE CWA TONIGHT. DID UP POPS A BIT TO
ENCOMPASS THE BETTER RADAR RETURNS AND OBSERVATIONS. MOST OF THE THIS
WILL BE LIGHT WITH GENERALLY A TENTH OF A INCH OR LESS. DID FRESHEN
UP TEMPS/DEWPOINTS/WINDS WITH LATEST OBS AND TRENDS.
UPDATE ISSUED AT 1100 PM EST SUN DEC 28 2014
RAIN IS TAPERING OFF SLIGHTLY FASTER THAN WAS NOTED IN THE PREVIOUS
UPDATE. TRIMMED BACK POPS AND HAVE THEM MOVING SE AT A FASTER RATE
NOW TO BETTER COORDINATE WITH THE CURRENT RADAR TRENDS. EVEN
STILL...WON/T BE SURPRISED IF THE POPS END UP MOVING OUT EVEN FASTER
THAN THE CURRENT FORECAST. THE CURRENT HRRR MODEL WOULD SUGGEST
CONTINUED SE MOVEMENT OF THE RAIN MOVING OUT OF MUCH OF THE CWA
BY 7Z...BUT BECOMING STALLED OUT ACROSS THE HIGHER TERRAIN FROM 7Z
THROUGH TOMORROW MORNING. THE MODEL HAS INITIALIZED WELL...BUT THIS
WILL BE SOMETHING TO WATCH.
UPDATE ISSUED AT 647 PM EST SUN DEC 28 2014
TWO MAIN CHANGES TO THE FORECAST. FIRST WAS TO CHANGE THE POPS OVER
THE NEXT FEW HOURS TO CENTER THE HIGHEST AMOUNTS OVER THE MORE
CENTRAL PORTION OF THE CWA...SLOWLY SHIFTING MORE EASTWARD INTO THE
HIGHEST TERRAIN OVER THE NEXT SEVERAL HOURS...THEN LINGERING SLIGHTLY
LONGER ACROSS THE SW CWA THAN WAS PREVIOUSLY FORECAST. THIS BETTER
ACCOUNTED FOR ONGOING CONDITIONS...AS WELL AS WHAT BOTH THE HI RES
AND SHORT TERM MODELS WERE FORECASTING. THE SECOND CHANGE WAS TO ADD
FOG WORDING TO THE CWA THROUGH THE OVERNIGHT HOURS. MUCH OF KY IS
REPORTING FOG...IN AREAS WITH AND WITHOUT RAIN. EXPECT THIS FOG TO
CONTINUE AS WE HEAD INTO THE OVERNIGHT HOURS WITH LOW LEVEL MOISTURE
FROM RAIN EXPECTED TO CONTINUE. THIS FOG SHOULD THEN BURN OFF DURING
THE MORNING HOURS AS DRIER AIR MOVES IN AND RAIN MOVES OUT. VALLEYS
WILL BE THE LAST TO CLEAR OUT. UPDATED THE NEAR TERM GRIDS WITH THE
LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS TO MAKE
SURE THE CURRENT CONDITIONS WERE REFLECTED IN THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 359 PM EST SUN DEC 28 2014
CURRENT CONDITIONS ACROSS THE AREA FEATURES RAIN CONTINUING TO MOVE
INTO THE AREA FROM THE SOUTHWEST. THE COLD FRONT HAS NOW PUSHED EAST
OF EASTERN KENTUCKY WITH NORTHWESTERLY FLOW NOW INTO THE AREA.
FREEZING TEMPERATURES LOOK TO BE NORTH AND WEST OF THE FORECAST AREA
AND SNOW IS NOT EXPECTED AT THIS TIME AS THE COLDER AIR IS A BIT TO
SLOW TO ADVECT INTO THE AREA BEFORE THE BULK OF THE MOISTURE EXITS TO THE
EAST TONIGHT. MEANWHILE...SURFACE LOW PRESSURE HAS DEVELOPED AND WILL
MOVE NORTHEAST THROUGH EASTERN TN TONIGHT. THIS WILL KEEP PRECIP
THROUGH FAR EASTERN KENTUCKY THROUGH THE NIGHT AS ANOTHER SURGE OF
MOISTURE WILL MOVE NORTHEAST. WITH THE MOIST LOW LEVELS...THOUGH
THERE WILL BE SOME CLOUD COVER...DO EXPECT SOME PATCHY FOG DEVELOPING
TONIGHT AND HAS ALREADY BEEN THE CASE IN SOME OF THE BLUEGRASS AREAS.
ESPECIALLY PLACES THAT REMAIN SATURATED THROUGH THE NIGHT.
CLOUD COVER AND PRECIP WILL SLOWLY MOVE OFF TO THE EAST FOR MONDAY
WITH SOME RAIN FALL SKIRTING ALONG THE FAR EASTERN COUNTIES AS THE
LOW EXITS OF TO THE EAST. HEADING INTO MONDAY NIGHT...THE COLDER AIR
WILL FILTER INTO THE AREA AND SOME LINGERING RAIN IN THE EAST MAY
CHANGE OR MIX TO SNOW IN THE HIGHER ELEVATIONS TOWARDS TUESDAY
MORNING. PARTIAL CLEARING IN THE NORTHWESTERN COUNTIES WILL RESULT IN
TEMPERATURES DROPPING INTO THE MID 20S FOR LOWS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 PM EST SUN DEC 28 2014
THE EXTENDED PORTION OF THE FORECAST WILL BE BROKEN UP INTO THREE
SEGMENTS. PART ONE...ISOLATED RAIN AND SNOW SHOWERS ARE FORECAST TO
LINGER IN THE NORTHERLY MEAGERLY MOIST FLOW BEHIND A DEPARTING COLD
FRONT AND UPPER LEVEL LOW PRESSURE SYSTEM. THE SECOND PERIOD WILL
FEATURE AN EAST TO WEST ELONGATED RIDGE OF HIGH PRESSURE THAT IS
EXPECTED TO DROP SOUTHWARD OUT OF THE GREAT LAKES REGION TUESDAY
THROUGH THURSDAY. PART THREE WILL FEATURE A WELL DEVELOPED AND VERY
MOISTURE LADEN WEATHER SYSTEM THAT WILL AFFECT THE REGION FROM
THURSDAY NIGHT THROUGH SUNDAY. THE WEATHER SYSTEM THAT WILL BE
LEAVING THE AREA ON TUESDAY SHOULD BRING NOTHING MORE THAN LIGHT
RAIN AND SNOW WITH LITTLE OR NO SNOW ACCUMULATION. TEMPERATURES TO
BEGIN THE PERIOD LOOK TO BE BELOW NORMAL...WITH HIGHS IN THE 40S
DURING THE DAY...AND LOWS TUESDAY NIGHT IN THE LOW TO MID 20S. AN
ARCTIC AIR MASS IS THEN PROGGED TO SETTLE OVER THE REGION MID WEEK.
HIGHS ON WEDNESDAY AND THURSDAY WILL LIKELY NOT MAKE IT OUT OF THE
30S. OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT WILL BE EVEN
CHILLIER...WITH THE MERCURY BOTTOMING OUT AROUND 20 WEDNESDAY
NIGHT...AND THE MID TO UPPER 20S THURSDAY NIGHT.
THE BIG STORY IN THE EXTENDED WILL BE THE WEATHER SYSTEM THAT IS
FORECAST TO SOAK THE AREA TOWARD THE END OF THE WEEK. THERE IS NO
QUESTION THAT A POTENT WEATHER SYSTEM WITH EXTENSIVE PRECIPITATION
WILL AFFECT THE STATE OF KENTUCKY FRIDAY AND SATURDAY. THE QUESTIONS
WITH THIS SYSTEM WILL BE HOW QUICKLY WILL PRECIPITATION MOVE INTO
THE AREA AND HOW MUCH OF THE PRECIP WILL BE IN THE FORM OF SNOW?
RIGHT NOW THE GFS IS MUCH SLOWER AND WARMER THAN THE ECMWF WITH THE
END OF WEEK WEATHER PATTERN. THE GFS HAS ITS LOW MOVING FURTHER
NORTH THAN THE ECMWF. THAT BEING SAID...WITH SO MUCH UNCERTAINTY
INVOLVED...DECIDED TO GO WITH A COMPROMISE BETWEEN THE TWO
MODELS...SLIGHTLY FAVORING THE COLDER ECMWF MODEL. THIS IS BASED ON
THE FACT THAT THE MODELS HAVE BEEN RUNNING A BIT TOO WARM LATELY
WITH REGARDS TO LOW AND MIDDLE LEVEL TEMPERATURES. AFTER A PERIOD OF
MIXED PRECIP THURSDAY EVENING...AN AREA OF LIGHT SNOW IS BEING
FORECAST TO DEVELOP LATE THURSDAY NIGHT THROUGH EARLY FRIDAY
MORNING. THERE COULD BE SOME LIGHT ACCUMULATIONS WITH THIS BAND OF
SNOW AS IT MOVES NORTH...BUT IT WILL LIKELY NOT STAY ON THE GROUND
LONG AS TEMPERATURES RISE INTO THE 40S ON FRIDAY. AN EXTENDED PERIOD
OF GOOD SOAKING RAIN IS EXPECTED FRIDAY THROUGH SATURDAY...WITH THE
POTENTIAL FOR SOME SNOW ALONG AND NORTH OF I-64 FRIDAY NIGHT AND
SATURDAY NIGHT...AS SOME NEAR FREEZING AIR COULD SPILL INTO THAT
AREA EACH NIGHT. AS IS COMMON IN WINTER...THE MODELS WILL NEED TO BE
WATCHED VERY CLOSELY TO SEE WHICH DIRECTION THINGS TREND...MORE RAIN
OR MORE SNOW WILL BE THE QUESTION AS WE MOVE FORWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 100 AM EST MON DEC 29 2014
FRONTAL BOUNDARY HAS MOVED SOUTH OF THE REGION TONIGHT WITH SURFACE
LOW RIDING UP ACROSS THE CAROLINA/TENNESSEE BORDER INDICATED BY 03Z
SURFACE ANALYSIS. MOST OF THE HEAVIER RAIN SHOWER ACTIVITY HAS MOVED
SOUTH OF THE REGION TONIGHT...HOWEVER DRIZZLE OR ISOLATED SHOWERS
WILL BE POSSIBLE OVERNIGHT. TAF SITES HAVE BEEN FLUCTUATING TONIGHT
WITH MOST SITES SEEING IFR TO LIFR CONDITIONS. SOME DRIER AIR HAS
BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE CWA WITH SYM CIGS
MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE AT MOST SITES AND
COULD BRING LOWER CONDITIONS TO THESE SITES THAT SEE THE HIGHER CIGS.
MOVING INTO TOMORROW MORNING WOULD EXPECT SOME IMPROVEMENTS TO THE
TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES ARE ONLY EXPECTED TO
IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO TOMORROW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
102 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 1100 PM EST SUN DEC 28 2014
RAIN IS TAPERING OFF SLIGHTLY FASTER THAN WAS NOTED IN THE PREVIOUS
UPDATE. TRIMMED BACK POPS AND HAVE THEM MOVING SE AT A FASTER RATE
NOW TO BETTER COORDINATE WITH THE CURRENT RADAR TRENDS. EVEN
STILL...WON/T BE SURPRISED IF THE POPS END UP MOVING OUT EVEN FASTER
THAN THE CURRENT FORECAST. THE CURRENT HRRR MODEL WOULD SUGGEST
CONTINUED SE MOVEMENT OF THE RAIN MOVING OUT OF MUCH OF THE CWA
BY 7Z...BUT BECOMING STALLED OUT ACROSS THE HIGHER TERRAIN FROM 7Z
THROUGH TOMORROW MORNING. THE MODEL HAS INITIALIZED WELL...BUT THIS
WILL BE SOMETHING TO WATCH.
UPDATE ISSUED AT 647 PM EST SUN DEC 28 2014
TWO MAIN CHANGES TO THE FORECAST. FIRST WAS TO CHANGE THE POPS OVER
THE NEXT FEW HOURS TO CENTER THE HIGHEST AMOUNTS OVER THE MORE
CENTRAL PORTION OF THE CWA...SLOWLY SHIFTING MORE EASTWARD INTO THE
HIGHEST TERRAIN OVER THE NEXT SEVERAL HOURS...THEN LINGERING SLIGHTLY
LONGER ACROSS THE SW CWA THAN WAS PREVIOUSLY FORECAST. THIS BETTER
ACCOUNTED FOR ONGOING CONDITIONS...AS WELL AS WHAT BOTH THE HI RES
AND SHORT TERM MODELS WERE FORECASTING. THE SECOND CHANGE WAS TO ADD
FOG WORDING TO THE CWA THROUGH THE OVERNIGHT HOURS. MUCH OF KY IS
REPORTING FOG...IN AREAS WITH AND WITHOUT RAIN. EXPECT THIS FOG TO
CONTINUE AS WE HEAD INTO THE OVERNIGHT HOURS WITH LOW LEVEL MOISTURE
FROM RAIN EXPECTED TO CONTINUE. THIS FOG SHOULD THEN BURN OFF DURING
THE MORNING HOURS AS DRIER AIR MOVES IN AND RAIN MOVES OUT. VALLEYS
WILL BE THE LAST TO CLEAR OUT. UPDATED THE NEAR TERM GRIDS WITH THE
LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS TO MAKE
SURE THE CURRENT CONDITIONS WERE REFLECTED IN THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 359 PM EST SUN DEC 28 2014
CURRENT CONDITIONS ACROSS THE AREA FEATURES RAIN CONTINUING TO MOVE
INTO THE AREA FROM THE SOUTHWEST. THE COLD FRONT HAS NOW PUSHED EAST
OF EASTERN KENTUCKY WITH NORTHWESTERLY FLOW NOW INTO THE AREA.
FREEZING TEMPERATURES LOOK TO BE NORTH AND WEST OF THE FORECAST AREA
AND SNOW IS NOT EXPECTED AT THIS TIME AS THE COLDER AIR IS A BIT TO
SLOW TO ADVECT INTO THE AREA BEFORE THE BULK OF THE MOISTURE EXITS TO THE
EAST TONIGHT. MEANWHILE...SURFACE LOW PRESSURE HAS DEVELOPED AND WILL
MOVE NORTHEAST THROUGH EASTERN TN TONIGHT. THIS WILL KEEP PRECIP
THROUGH FAR EASTERN KENTUCKY THROUGH THE NIGHT AS ANOTHER SURGE OF
MOISTURE WILL MOVE NORTHEAST. WITH THE MOIST LOW LEVELS...THOUGH
THERE WILL BE SOME CLOUD COVER...DO EXPECT SOME PATCHY FOG DEVELOPING
TONIGHT AND HAS ALREADY BEEN THE CASE IN SOME OF THE BLUEGRASS AREAS.
ESPECIALLY PLACES THAT REMAIN SATURATED THROUGH THE NIGHT.
CLOUD COVER AND PRECIP WILL SLOWLY MOVE OFF TO THE EAST FOR MONDAY
WITH SOME RAIN FALL SKIRTING ALONG THE FAR EASTERN COUNTIES AS THE
LOW EXITS OF TO THE EAST. HEADING INTO MONDAY NIGHT...THE COLDER AIR
WILL FILTER INTO THE AREA AND SOME LINGERING RAIN IN THE EAST MAY
CHANGE OR MIX TO SNOW IN THE HIGHER ELEVATIONS TOWARDS TUESDAY
MORNING. PARTIAL CLEARING IN THE NORTHWESTERN COUNTIES WILL RESULT IN
TEMPERATURES DROPPING INTO THE MID 20S FOR LOWS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 PM EST SUN DEC 28 2014
THE EXTENDED PORTION OF THE FORECAST WILL BE BROKEN UP INTO THREE
SEGMENTS. PART ONE...ISOLATED RAIN AND SNOW SHOWERS ARE FORECAST TO
LINGER IN THE NORTHERLY MEAGERLY MOIST FLOW BEHIND A DEPARTING COLD
FRONT AND UPPER LEVEL LOW PRESSURE SYSTEM. THE SECOND PERIOD WILL
FEATURE AN EAST TO WEST ELONGATED RIDGE OF HIGH PRESSURE THAT IS
EXPECTED TO DROP SOUTHWARD OUT OF THE GREAT LAKES REGION TUESDAY
THROUGH THURSDAY. PART THREE WILL FEATURE A WELL DEVELOPED AND VERY
MOISTURE LADEN WEATHER SYSTEM THAT WILL AFFECT THE REGION FROM
THURSDAY NIGHT THROUGH SUNDAY. THE WEATHER SYSTEM THAT WILL BE
LEAVING THE AREA ON TUESDAY SHOULD BRING NOTHING MORE THAN LIGHT
RAIN AND SNOW WITH LITTLE OR NO SNOW ACCUMULATION. TEMPERATURES TO
BEGIN THE PERIOD LOOK TO BE BELOW NORMAL...WITH HIGHS IN THE 40S
DURING THE DAY...AND LOWS TUESDAY NIGHT IN THE LOW TO MID 20S. AN
ARCTIC AIR MASS IS THEN PROGGED TO SETTLE OVER THE REGION MID WEEK.
HIGHS ON WEDNESDAY AND THURSDAY WILL LIKELY NOT MAKE IT OUT OF THE
30S. OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT WILL BE EVEN
CHILLIER...WITH THE MERCURY BOTTOMING OUT AROUND 20 WEDNESDAY
NIGHT...AND THE MID TO UPPER 20S THURSDAY NIGHT.
THE BIG STORY IN THE EXTENDED WILL BE THE WEATHER SYSTEM THAT IS
FORECAST TO SOAK THE AREA TOWARD THE END OF THE WEEK. THERE IS NO
QUESTION THAT A POTENT WEATHER SYSTEM WITH EXTENSIVE PRECIPITATION
WILL AFFECT THE STATE OF KENTUCKY FRIDAY AND SATURDAY. THE QUESTIONS
WITH THIS SYSTEM WILL BE HOW QUICKLY WILL PRECIPITATION MOVE INTO
THE AREA AND HOW MUCH OF THE PRECIP WILL BE IN THE FORM OF SNOW?
RIGHT NOW THE GFS IS MUCH SLOWER AND WARMER THAN THE ECMWF WITH THE
END OF WEEK WEATHER PATTERN. THE GFS HAS ITS LOW MOVING FURTHER
NORTH THAN THE ECMWF. THAT BEING SAID...WITH SO MUCH UNCERTAINTY
INVOLVED...DECIDED TO GO WITH A COMPROMISE BETWEEN THE TWO
MODELS...SLIGHTLY FAVORING THE COLDER ECMWF MODEL. THIS IS BASED ON
THE FACT THAT THE MODELS HAVE BEEN RUNNING A BIT TOO WARM LATELY
WITH REGARDS TO LOW AND MIDDLE LEVEL TEMPERATURES. AFTER A PERIOD OF
MIXED PRECIP THURSDAY EVENING...AN AREA OF LIGHT SNOW IS BEING
FORECAST TO DEVELOP LATE THURSDAY NIGHT THROUGH EARLY FRIDAY
MORNING. THERE COULD BE SOME LIGHT ACCUMULATIONS WITH THIS BAND OF
SNOW AS IT MOVES NORTH...BUT IT WILL LIKELY NOT STAY ON THE GROUND
LONG AS TEMPERATURES RISE INTO THE 40S ON FRIDAY. AN EXTENDED PERIOD
OF GOOD SOAKING RAIN IS EXPECTED FRIDAY THROUGH SATURDAY...WITH THE
POTENTIAL FOR SOME SNOW ALONG AND NORTH OF I-64 FRIDAY NIGHT AND
SATURDAY NIGHT...AS SOME NEAR FREEZING AIR COULD SPILL INTO THAT
AREA EACH NIGHT. AS IS COMMON IN WINTER...THE MODELS WILL NEED TO BE
WATCHED VERY CLOSELY TO SEE WHICH DIRECTION THINGS TREND...MORE RAIN
OR MORE SNOW WILL BE THE QUESTION AS WE MOVE FORWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 100 AM EST MON DEC 29 2014
FRONTAL BOUNDARY HAS MOVED SOUTH OF THE REGION TONIGHT WITH SURFACE
LOW RIDING UP ACROSS THE CAROLINA/TENNESSEE BORDER INDICATED BY 03Z
SURFACE ANALYSIS. MOST OF THE HEAVIER RAIN SHOWER ACTIVITY HAS MOVED
SOUTH OF THE REGION TONIGHT...HOWEVER DRIZZLE OR ISOLATED SHOWERS
WILL BE POSSIBLE OVERNIGHT. TAF SITES HAVE BEEN FLUCTUATING TONIGHT
WITH MOST SITES SEEING IFR TO LIFR CONDITIONS. SOME DRIER AIR HAS
BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE CWA WITH SYM CIGS
MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE AT MOST SITES AND
COULD BRING LOWER CONDITIONS TO THESE SITES THAT SEE THE HIGHER CIGS.
MOVING INTO TOMORROW MORNING WOULD EXPECT SOME IMPROVEMENTS TO THE
TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES ARE ONLY EXPECTED TO
IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO TOMORROW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
348 AM CST MON DEC 29 2014
.SHORT TERM...
COLD FRONT HAS FINALLY PUSHED OFFSHORE AND IS SLOWLY PROGRESSING
EASTWARD. A BAND OF LIGHT TO MODERATE RAN HAS DEVELOPED ACROSS
PLAQUEMINES PARISH...EXTENDING NORTHEASTWARD TOWARDS THE ALABAMA
COAST. THE HRRR SHOWS THIS ACTIVITY HANGING AROUND FOR A COUPLE MORE
HOURS BEFORE SHIFTING OFFSHORE. THIS COINCIDES WELL WITH LATEST
WATER VAPOR IMAGERY WHICH INDICATES THAT DRIER MID LEVEL AIR SHOULD
BE ARRIVING AT ABOUT THAT SAME TIME. ISOLATED SHOWERS COULD LINGER
FOR A FEW HOURS IN THE MORNING ALONG COASTAL AREAS. OTHERWISE...IT
DOES APPEAR LOW LOW LEVEL STRATUS DECK WILL HANG AROUND ALL DAY AND
TONIGHT AS WELL. HAVE MADE ADJUSTMENTS TO THE ZONES FOR THAT. IN
ADDITION...HAVE KEPT HIGHS A COUPLE DEGREES COOLER THAN MAV GUIDANCE
TO ACCOUNT FOR LESS THAN EXPECTED INSOLATION.
AN UPPER LEVEL TROUGH DROPPING OUT OF CANADA EARLY THIS WEEK WILL
SEND A SECONDARY SURGE OF COLDER AIR TO THE AREA TUESDAY. STRONG
COLD AIR ADVECTION WILL PERSIST FOR AT LEAST A COUPLE DAYS. THIS
WILL DROP TEMPERATURES TO ABOUT 10 DEGREES BELOW NORMAL WED AND
THURS. COULD SEE FREEZE TEMPS FOR LOWS THURSDAY MORNING.
.LONG TERM...
MODELS STILL SHOWING AN UPPER LEVEL LOW CLOSING OFF OVER THE DESERT
SOUTHWEST MID WEEK AND TRACKING EASTWARD ACROSS THE CENTRAL PLAINS
THIS WEEKEND. SHOWERS AND THUNDERSTORMS ARE EXPECTED LOCALLY AHEAD
OF THIS FEATURE AS MOISTURE INCREASES ACROSS THE AREA. HAVE BUMPED
UP POPS TO 60 PERCENT ON FRIDAY AND 60-70 PCT FOR SATURDAY.
INSTABILITY LOOKS TO BE DEVELOPING SATURDAY AS LOW LEVELS WARM AND
MID/UPPER LEVEL COOLING TAKES PLACE. A FEW MARGINALLY STRONG TO
SEVERE STORMS COULD DEVELOP BUT THATS STILL SEVERAL DAYS OUT AT THIS
TIME TO KNOW WITH ANY DEGREE OF CERTAINTY. UPPER/SFC LOW PLACEMENT
AMONG OTHER THINGS COULD CHANGE QUITE A BIT BETWEEN NOW AND THEN.
JUST WANTED TO MENTION THE POSSIBILITY.
MEFFER
&&
.AVIATION...
A LOW STRATUS DECK WILL REMAIN OVER THE TERMINALS THROUGH THE ENTIRE
FORECAST PERIOD. CEILINGS WILL GENERALLY RANGE FROM 300 TO 800
FEET..RESULTING IN LIFR AND IFR CONDITIONS AT ALL OF THE TERMINALS
THROUGH AROUND 15Z. AFTER 15Z...CONDITIONS SHOULD IMPROVE
SLIGHTLY...WITH CEILINGS GENERALLY RANGING FROM 1000 TO 1500 FEET.
THESE MVFR CONDITIONS WILL PERSIST THROUGH 00Z. HOWEVER...STRATUS
BUILD DOWN WILL OCCUR AFTER 00Z...AS AN ELEVATED INVERSION
STRENGTHENS. A RETURN TO IFR AND LIFR CEILINGS RANGING FROM 300 TO
800 FEET IS EXPECTED BY 03Z. 32
&&
.MARINE...
NORTHEAST FLOW OF 10 TO 15 KNOTS WILL RISE INTO SMALL CRAFT EXERCISE
CAUTION RANGE LATE TONIGHT AND TOMORROW AS A COOLER AND DRIER
AIRMASS ADVECTS OVER THE COASTAL WATERS. THIS STRONGER NORTHEAST
FLOW OF 15 TO 20 KNOTS WILL PERSIST THROUGH WEDNESDAY NIGHT. WINDS
WILL VEER TO AN EASTERLY DIRECTION AS THE HIGH SHIFTS TO THE
EAST...AND ANOTHER AREA OF LOW PRESSURE BEGINS TO FORM IN THE
WESTERN GULF OF MEXICO. AS THE LOW SLOWLY MOVES NORTH INTO EASTERN
TEXAS AND WESTERN LOUISIANA FRIDAY AND SATURDAY...WINDS WILL FURTHER
VEER TO THE SOUTHEAST AND REMAIN IN EXERCISE CAUTION RANGE. SEAS
WILL INCREASE TO 4 TO 6 FEET IN THE OUTER WATERS DURING THIS PERIOD. 32
&&
.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
FLOOD WATCH
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 54 42 55 33 / 10 10 0 0
BTR 57 44 58 36 / 10 10 0 0
ASD 61 46 60 35 / 20 0 0 0
MSY 60 49 59 42 / 20 0 0 0
GPT 63 47 60 38 / 20 0 0 0
PQL 63 47 61 35 / 20 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS BALTIMORE MD/WASHINGTON DC
359 AM EST MON DEC 29 2014
.SYNOPSIS...
WEAK DISTURBANCES WILL RIDE ALONG A COLD FRONT...MAINLY TO OUR
SOUTH...TODAY THROUGH TUESDAY. HIGH PRESSURE WILL BUILD INTO THE EASTERN
HALF OF THE COUNTRY FOR THE SECOND HALF OF THE WEEK. LOW PRESSURE
IS EXPECTED TO AFFECT THE MID ATLANTIC REGION THIS WEEKEND.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 08Z...1055MB SFC HIGH IS NORTH OF CALGARY WHILE AN UPR LOW IS
OVER NRN QUEBEC AND AN UPR TROUGH IS OVER THE INTERMOUNTAIN WEST. A
WEAK COLD FRONT EXTENDS FROM A LOW EAST OF NEWFOUNDLAND TO THE
CAROLINAS. HIGH PRESSURE WILL BUILD NORTH OF THE CWA TODAY...WITH A
NELY FLOW OF 10 MPH OR SO SETTING UP. RAIN CURRENTLY ALONG SOUTHERN
PERIPHERY OF CWA (WITH PATCHY SPRINKLES/LIGHT RAIN UP THROUGH THE DC
METRO AREA) WILL CONTINUE TO DRIFT SOUTH THROUGH TODAY. REDUCED POPS
ACROSS THE BALT-WASH METRO PER RECENT HRRR RUNS AND OBSERVED RADAR
TRENDS. RAIN WILL CONTINUE TO BE LIGHT WITH LESS THAN A TENTH INCH
QPF. MAX TEMPS LOW TO MID 40S UNDER PERSISTENT MID-LEVEL CLOUDS.
ELY COMPONENT WILL PROMOTE PRECIP DEVELOPMENT FOR CNTRL VA BLUE
RIDGE AND AREAS FARTHER WEST. COLDER AIR THERE WILL ALLOW SOME SNOW
ABOVE ABOUT 2500 FT TODAY...LOWERING TO AROUND 1000 FT TONIGHT.
EXPANDED SNOWFALL AREAS TO INCLUDE DUSTING/0.1 INCH IN THE CNTRL
SHEN VLY...STILL LESS THAN INCH FOR RIDGES. ELSEWHERE DRY AND
CLOUDY...MIN TEMPS UPR 20S TO LOW 30S (MID 30S FOR NEAR SHORE).
&&
.SHORT TERM /TUESDAY/...
PRECIP SHIFTS SOUTH AS 1030MB SFC PRES SHIFTS INTO THE
CWA. LIGHT NLY FLOW AND MAX TEMPS UPR 30S TO LOW 40S UNDER CLEARING
SKIES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGH PRES XPCTD TO BUILD INTO THE AREA FOR NEW YRS EVE...SO WX WL
NOT BE A PROBLEM WED NGT OR THE 1ST DAY OF 2015. THE HIGH SHOULD
RMN IN CONTROL OF MID ATLC WX THRU THE END OF THE WK. THIS WL
ALLOW TEMPS TO MODERATE - THU MRNG LOWS WL MAINLY BE IN THE
L20S...BY SAT MRNG ABT TEN DEGS WARMER. THE SAME WL BE TRUE W/
HIGH TEMPS - THU ARND 40...A50 SAT.
LOW PRES WL BE INFLUENCING THE ERN U.S. OVR THE WKND. THERE IS
DIFFERENCE IN THE MDLS AS TO THE TRJECTORY OF THE SYSTEM - EURO
HAS IT ON A SRN TRACK WHILE THE GFS TAKES IT INTO THE ERN GRT LKS
ALNG W/ A COLD FNT PUSHING ONTO THE E CST. OBVIOUSLY THIS WL NEED
TO RESOLVED IN THE COMING DAYS. AT THIS MOMENT P-TYPE LOOKS TO BE
LIQUID. IF TEMPS ARE ABLE TO DROP BLO FRZG THEN FZRA WL NEED TO BE
CONSIDERED BUT THAT IS A LONG WAY AWAY.
LOOKING AT THE HEMISPHERIC 500 MB PATTERN OF BOTH THE GFS AND
ECM...THE COLDEST AIR LOOKS TO RMN LOCKED OVR HUDSON BAY INTO NEXT
WK. JAN 5-8 2014 SAW XTRMLY COLD AIR IN THE CWA AND THE ISSUANCE OF
MULTIPLE WIND CHILL ADVSRIES AND WRNGS (ACTUAL WIND CHILL OF -11
AT DCA....BLO -40 IN THE HIGHLANDS). NO REPEAT IN 2015.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR CONDS CONTINUE TO PREVAIL AS COLD FRONT AND ASSOCIATED RAIN
CONTINUES TO MOVE SOUTH.
VFR CONDS XPCTD TUE NGT THRU FRI.
&&
.MARINE...
LIGHT SWLY FLOW VEERS NWLY TODAY AS A COLD FRONT CROSSES THE WATERS
THIS AFTERNOON AND EVENING. COULD BE A NLY SURGE WITH GUSTS AROUND
18 KT LATE TONIGHT. DID NOT RAISE AN SCA DUE TO UNCERTAINTY...BUT
ONE OUT OF SANDY POINT IS POSSIBLE INTO MONDAY.
NO PROBS XPCTD TUE NGT THRU FRI ON THE WATERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
358 AM EST MON DEC 29 2014
.SYNOPSIS...
WEAK DISTURBANCES WILL RIDE ALONG A COLD FRONT...MAINLY TO OUR
SOUTH...TODAY THROUGH TUESDAY. HIGH PRESSURE WILL BUILD INTO THE EASTERN
HALF OF THE COUNTRY FOR THE SECOND HALF OF THE WEEK. LOW PRESSURE
IS EXPECTED TO AFFECT THE MID ATLANTIC REGION THIS WEEKEND.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 08Z...1055MB SFC HIGH IS NORTH OF CALGARY WHILE AN UPR LOW IS
OVER NRN QUEBEC AND AN UPR TROUGH IS OVER THE INTERMOUNTAIN WEST. A
WEAK COLD FRONT EXTENDS FROM A LOW EAST OF NEWFOUNDLAND TO THE
CAROLINAS. HIGH PRESSURE WILL BUILD NORTH OF THE CWA TODAY...WITH A
NELY FLOW OF 10 MPH OR SO SETTING UP. RAIN CURRENTLY ALONG SOUTHERN
PERIPHERY OF CWA (WITH PATCHY SPRINKLES/LIGHT RAIN UP THROUGH THE DC
METRO AREA) WILL CONTINUE TO DRIFT SOUTH THROUGH TODAY. REDUCED POPS
ACROSS THE BALT-WASH METRO PER RECENT HRRR RUNS AND OBSERVED RADAR
TRENDS. RAIN WILL CONTINUE TO BE LIGHT WITH LESS THAN A TENTH INCH
QPF. MAX TEMPS LOW TO MID 40S UNDER PERSISTENT MID-LEVEL CLOUDS.
ELY COMPONENT WILL PROMOTE PRECIP DEVELOPMENT FOR CNTRL VA BLUE
RIDGE AND AREAS FARTHER WEST. COLDER AIR THERE WILL ALLOW SOME SNOW
ABOVE ABOUT 2500 FT TODAY...LOWERING TO AROUND 1000 FT TONIGHT.
EXPANDED SNOWFALL AREAS TO INCLUDE DUSTING/0.1 INCH IN THE CNTRL
SHEN VLY...STILL LESS THAN INCH FOR RIDGES. ELSEWHERE DRY AND
CLOUDY...MIN TEMPS UPR 20S TO LOW 30S (MID 30S FOR NEAR SHORE).
&&
.SHORT TERM /TUESDAY/...
PRECIP SHIFTS SOUTH AS 1030MB SFC PRES SHIFTS INTO THE
CWA. LIGHT NLY FLOW AND MAX TEMPS UPR 30S TO LOW 40S UNDER CLEARING
SKIES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGH PRES XPCTD TO BUILD INTO THE AREA FOR NEW YRS EVE...SO WX WL
NOT BE A PROBLEM WED NGT OR THE 1ST DAY OF 2015. THE HIGH SHOULD
RMN IN CONTROL OF MID ATLC WX THRU THE END OF THE WK. THIS WL
ALLOW TEMPS TO MODERATE - THU MRNG LOWS WL MAINLY BE IN THE
L20S...BY SAT MRNG ABT TEN DEGS WARMER. THE SAME WL BE TRUE W/
HIGH TEMPS - THU ARND 40...A50 SAT.
LOW PRES WL BE INFLUENCING THE ERN U.S. OVR THE WKND. THERE IS
DIFFERENCE IN THE MDLS AS TO THE TRJECTORY OF THE SYSTEM - EURO
HAS IT ON A SRN TRACK WHILE THE GFS TAKES IT INTO THE ERN GRT LKS
ALNG W/ A COLD FNT PUSHING ONTO THE E CST. OBVIOUSLY THIS WL NEED
TO RESOLVED IN THE COMING DAYS. AT THIS MOMENT P-TYPE LOOKS TO BE
LIQUID. IF TEMPS ARE ABLE TO DROP BLO FRZG THEN FZRA WL NEED TO BE
CONSIDERED BUT THAT IS A LONG WAY AWAY.
LOOKING AT THE HEMISPHERIC 500 MB PATTERN OF BOTH THE GFS AND
ECM...THE COLDEST AIR LOOKS TO RMN LOCKED OVR HUDSON BAY INTO NEXT
WK. JAN 5-8 2014 SAW XTRMLY COLD AIR IN THE CWA AND THE ISSUANCE OF
MULTIPLE WIND CHILL ADVSRIES AND WRNGS (ACTUAL WIND CHILL OF -11
AT DCA....BLO -40 IN THE HIGHLANDS). NO REPEAT IN 2015.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR CONDS XPCTD TUE NGT THRU FRI.
&&
.MARINE...
NO PROBS XPCTD TUE NGT THRU FRI ON THE WATERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1157 PM EST SUN DEC 28 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 216 PM EST SUN DEC 28 2014
PERSISTENT LIGHT AND FLUFFY LAKE EFFECT IN THE NORTHWEST WIND SNOW
BELTS WILL BE THE NORM FOR THE SHORT TERM FORECAST.
A SURFACE TROUGH SWEPT SOUTHEAST ACROSS UPPER MICHIGAN THIS
MORNING AND EARLY AFTERNOON AND HAS SWITCHED WINDS TO THE NORTHWEST
AND BROUGHT MUCH COLDER AIR INTO THE AREA. 850MB TEMPS AT THIS TIME
ON THE RAP ANALYSIS ARE -18C OVER WESTERN LAKE SUPERIOR AND WESTERN
UPPER MICHIGAN. THIS COLD AIR...AIDED BY MOISTURE FROM THE SURFACE
TROUGH THAT SWEPT THROUGH THE AREA...LED TO SOME LAKE EFFECT SNOW IN
THE WEST AND NOW NORTHWEST WIND SNOWBELTS THROUGH THE DAY. WHILE
THERE WERE SOME STRONGER SHOWERS THIS MORNING...ASSISTED BY
CONVERGENCE ALONG THE FRONT AND FROM THE SOUTHERN EDGE OF THE
SHORTWAVE MOVING EAST JUST TO THE NORTH OF LAKE SUPERIOR...THEY HAVE
NOW TRANSITIONED TO MORE OF A MULTIBAND LES LOOK ON SATELLITE OVER
WESTERN UPPER MICHIGAN. USING THE EXPERIMENTAL SSEC SATELLITE
DERIVED SNOWFALL RATES...IT APPEARS THAT SOME AREAS ARE SEEING
TRANSIENT BANDS OF 0.5 IN/HR RATES AND THAT SEEMS TO MATCH UP WITH
VISIBILITY REPORTS AT KCMX. WITH THE DEEPER MOISTURE STARTING TO
PULL OUT OF THAT AREA...HAVE ALREADY SEEN SOME WEAKENING OVER
WESTERN LAKE SUPERIOR...HELPED BY INVERSION HEIGHTS FALLING
BEHIND THE TROUGH. THE 12Z KINL SOUNDING HAD INVERSION HEIGHTS
AROUND 900MB OR 3KFT...BUT WITH SOME LAKE MODIFICATION THEY SHOULD
BE IN THE 4-5KFT RANGE. OVER THE EAST...THERE WAS A STRONGER BAND
BETWEEN MUNISING AND MINER/S CASTLE THIS MORNING THAT LIKELY
PRODUCED A COUPLE-FEW INCHES OF SNOW. THIS BAND WAS AIDED BY THE
CONVERGENT FLOW OFF MARQUETTE COUNTY AHEAD OF THE SURFACE TROUGH.
BUT NOW THAT THE TROUGH IS MOVING THROUGH NORTH CENTRAL UPPER
MICHIGAN...THE BAND HAS BECOME MUDDLED. WITH THE LAKE EFFECT
TRANSITIONING TO MULTIBAND OVER THE EASTERN LAKE...ACCUMULATIONS
SHOULD BE LIMITED THE REST OF THE AFTERNOON.
OVERALL...LITTLE CHANGE IN THE OVERALL CONDITIONS OVER THE CWA
DURING THE SHORT TERM PERIOD...AS HIGH PRESSURE RIDGE BUILDS OVER
THE AREA FROM A STRONG HIGH IN NORTHWEST CANADA. WITH 875MB TEMPS
FALLING TO -21C...EXPECT HIGH POP LOW QPF LAKE EFFECT TO CONTINUE
THROUGH THE PERIOD IN THE NORTHWEST WIND SNOWBELTS. THERE DOES
APPEAR TO BE A BRIEF PERIOD OF BACKING WINDS OVERNIGHT AS A WEAK
TROUGH MOVES THROUGH TONIGHT BEFORE SETTLING BACK TO NORTHWEST WINDS
FOR MONDAY. THIS WEAK TROUGH WILL BRING A LITTLE MORE LOW LEVEL
MOISTURE TO THE AREA FOR THE LAKE EFFECT TO WORK WITH LATE TONIGHT
INTO MONDAY MORNING (SEEN ON THE 12Z CWPL SOUNDING). BUT THE RIDGE
MOVING OVER THE AREA WILL KEEP THE LOWER INVERSION HEIGHTS IN PLACE
THROUGH THE PERIOD AND KEEP SNOWFALL AMOUNTS IN CHECK. FOR TONIGHT
AND AGAIN ON MONDAY...HAVE THE NORTHWEST WIND SNOW BELTS RECEIVING
1-3 INCHES OF FLUFFY SNOW EVERY 12 HOURS...LARGELY HELPED BY THE
ENTIRE CLOUD BEING WITHIN THE DGZ. WITH THE LONGER FETCH AND IN TURN
LAKE MODIFICATION...HAVE A LITTLE HIGHER AMOUNTS OVER THE EAST BUT
STILL ONLY LOCALIZED 4 INCH AMOUNTS. THERE ARE SOME INDICATIONS OF
LOW LEVEL DRYING LATE TOMORROW AFTERNOON WHICH COULD WEAKEN THE LAKE
EFFECT SOME AND HAVE LOWERED THE POPS A LITTLE TO ACCOUNT FOR THAT.
AS IS NORMALLY THE CASE IN THE LAKE EFFECT REGIMES...LOWS TONIGHT
WILL DEPEND ON CLOUD COVER. WHERE CLEARING IS EXPECTED TO
OCCUR...HAVE LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO.
OTHERWISE...UNDER THE CLOUDS WOULD EXPECT TEMPS IN THE UPPER SINGLE
DIGITS OR LOWER TEENS. HIGHS TOMORROW WILL BE CLOSE TO 10 DEGREES
BELOW NORMAL AND IN THE TEENS ABOVE ZERO.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 PM EST SUN DEC 28 2014
TODAYS MEDIUM RANGE MODELS STRONGLY SUPPORT LONG TERM FCST PRODUCED
OVER THE LAST 3 DAYS. SO...FCST CHANGES IN THE LONG TERM TODAY WILL
BE MINOR. BIGGEST FCST CHALLENGE WILL OCCUR AT THE END OF THE
WEEK/WEEKEND. MORE ON THAT LATER. THE LONG ADVERTISED SIGNIFICANT
PATTERN CHANGE ACROSS NAMERICA IS NOW WELL UNDERWAY AS A STRONG
RIDGE IS BUILDING N THRU ALASKA. 12Z RAOBS SHOW 12HR 500MB HEIGHT
RISES OF 130-150M IN NRN ALASKA/ADJACENT FAR NW CANADA...AND HEIGHT
ANOMALIES ARE NOW 2 STANDARD DEVIATIONS ABOVE THE LONG TERM LATE DEC
AVG. 500MB HEIGHT ANOMALIES ARE STILL FCST TO PEAK AT 2.5 STANDARD
DEVIATIONS LATER TODAY THRU EARLY WED. OF COURSE...THE DOWNSTREAM
RESPONSE WILL BE A DEVELOPING CNTRL/ERN NAMERICA TROF. THIS
AMPLIFIED PATTERN WILL ALLOW THE BUILDUP AND EXPANSION OF ARCTIC AIR
ACROSS CANADA THAT WILL SPILL S INTO THE CONUS...SIMILAR TO THE
PATTERN OBSERVED MOST OF LAST WINTER AND LAST MONTH. SO...AFTER AN
EXTENDED PERIOD OF MOSTLY ABOVE NORMAL TEMPS OVER THE LAST 3
WEEKS...A BLO NORMAL TEMP REGIME WILL TAKE HOLD ON MON AND CONTINUE
THRU AT LEAST THE NEXT 10 DAYS...THOUGH A DAY OR TWO MAY SEE TEMPS
CLOSE TO NORMAL DURING THAT TIME. THERE ARE INDICATIONS THAT THE
MOST SIGNIFICANT CHILL COULD OCCUR IN THE 7-10 DAY TIME FRAME.
FARTHER OUT TO DAY 16...MAJORITY OF GEM ENSEMBLES STILL INDICATE
DEAMPLIFICATION AND A TREND BACK TOWARD NORMAL TEMPS BY MID JAN.
CFSV2 GOES FURTHER TO BRING A RETURN OF A WARM PATTERN/ABOVE NORMAL
TEMPS FOR MID/LATE JAN. WE`LL SEE. AS FOR PCPN...PCPN THIS WEEK WILL
BE CONFINED ALMOST EXCLUSIVELY TO THE LAKE EFFECT SNOW BELTS NEAR
LAKE SUPERIOR AS COLD NW FLOW PREVAILS. AS HAS BEEN THE CASE THE
LAST FEW DAYS...THERE CONTINUE TO BE INDICATIONS THAT A LOW PRES
SYSTEM COULD TRACK FROM THE SRN PLAINS TO THE GREAT LAKES LATE
WEEK/WEEKEND. WHILE THIS STILL SEEMS LIKE A LOW PROBABILITY BASED ON
ALL AVBL MEDIUM RANGE GUIDANCE (AT LEAST AS FAR AS BRINGING
SIGNIFICANT PCPN INTO UPPER MI)...THERE ARE SUBTLE MULTI-MODEL
TRENDS SUPPORTING AN INCREASED LIKELIHOOD OF AT LEAST WIDESPREAD
-SN...INCLUDING LAKE ENHANCEMENT NEAR LAKE SUPERIOR. LATE
WEEK/WEEKEND WILL CONTINUE TO BE A TIME FRAME TO MONITOR IN THE
COMING DAYS.
BEGINNING MON NIGHT THRU TUE NIGHT...THE COLDEST AIR OF THIS INITIAL
SURGE OF ARCTIC AIR WILL SETTLE OVER THE AREA ON TUE WHEN 850MB
TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY BEING
THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL WILL
BE IN THE 5 TO 15F RANGE...THOUGH OVER THE FAR W AROUND KIWD...TEMPS
MAY ONLY RISE TO JUST ABOVE 0F. MON NIGHT AND TUE NIGHT...SUBZERO
MIN TEMPS WILL BE THE RULE IN THE INTERIOR AWAY FROM LAKE EFFECT
CLOUDS/SNOW. TUE NIGHT WILL LIKELY BE COLDEST WITH TEMPS IN THE
INTERIOR W HALF SLIPPING TO -10F OR LWR. SUBZERO TEMPS SHOULD COVER
A WIDER AREA ON TUE NIGHT AS WELL SINCE WINDS BACKING MORE WESTERLY
WILL RESULT IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI.
COMBINED WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO
THE -15 TO -25F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD
AIR...NMRS SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY
NW TO W WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO
LES WILL OVERALL BE ON THE LIGHT SIDE (1-4IN/12HRS). HOWEVER...WHERE
FETCH ACROSS THE LAKE IS LONGEST...ALLOWING MOST LAKE MODERATION...
DGZ WILL DOMINATE THE CONVECTIVE LAYER...AND THIS MAY ALLOW FOR SOME
ADVY LEVEL SNOW ACCUMULATIONS...IN PARTICULAR WHERE LONGER FETCH AND
LOCALIZED ENHANCED CONVERGENCE WORK TOGETHER. SIMILAR TO THE LAST
FEW DAYS OF MODEL RUNS...SHORTWAVE TROF SWINGING ACROSS THE AREA ON
TUE WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING
INVERSION HEIGHTS (FOR ROUGHLY 6HRS)...RESULTING IN AN INCREASE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. BLSN MAY
BECOME AN ISSUE THERE ON NEW YEARS EVE...ESPECIALLY IF SHSN COVERAGE
REMAINS NMRS OR GREATER.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH AFORMENTIONED SHORTWAVE TROF
SWINGING ACROSS NRN ONTARIO WILL THEN SWEEP ACROSS THE AREA EARLY ON
NEW YEARS DAY...ENHANCING LES FOR A TIME AND PROBABLY BRINGING AT
ISOLD/SCT -SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
INCREASING MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR A BAND OF -SN TO DEVELOP OVER THE NRN PLAINS
AND THEN STREAK E INTO THE UPPER LAKES...BUT PROBABLY NOT UNTIL FRI
NIGHT.
ON INTO SAT...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW THAT
WILL BE OVER THE SW STATES MIDWEEK. THE GFS HAS BEEN VERY CONSISTENT
ON THE NW SIDE OF GUIDANCE IN TAKING THAT ENERGY INTO THE GREAT
LAKES REGION. FOR A NUMBER OF RUNS...IT HAS TRACKED A SFC LOW NE...
ROUGHLY ACROSS THE SE HALF OF LWR MI. THE 00Z ECMWF STARTED TO TREND
SLIGHTLY N AND W WITH TRACK...BUT THE 12Z RUN IS MUCH MORE
SUPPRESSED WITH THE LOW...A RESULT OF THE NE PACIFIC RIDGE BEING
LESS PRONOUNCED WHICH LEADS TO FLATTER DOWNSTREAM FLOW. THERE A FEW
MORE GEM ENSEMBLES SIMILAR TO THE GFS TODAY...BUT THEY ARE STILL A
DEFINITE MINORITY. MUCH WILL DEPEND ON THE STRUCTURE/AMPLITUDE OF
THE NE PACIFIC RIDGE...BUT AT THIS POINT...GIVEN TODAYS AND RECENT
DAYS MEDIUM RANGE GUIDANCE...THE PROBABILITY IS STILL VERY LOW FOR
THE SFC LOW TO TRACK FAR ENOUGH N AND W TO BRING SIGNIFICANT PCPN TO
THE FCST AREA. HOWEVER...AIDED BY NRN STREAM ENERGY...THERE SHOULD
BE SOME -SN ACROSS THE FCST AREA ON SAT ALONG WITH THE POTENTIAL FOR
LAKE ENHANCEMENT NEAR LAKE SUPERIOR. ARCTIC AIR WILL FLOW BACK INTO
THE UPPER LAKES ON SUN...RENEWING LES IN AREAS FAVORED BY NW WINDS.
COLDEST AIR OF THE SEASON COULD FOLLOW FOR MON/TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1157 PM EST SUN DEC 28 2014
NORTHWEST FLOW LAKE EFFECT WILL BE THE MAIN ITEM OF CONCERN. WITH A
STRONG INVERSION AROUND 3KFT ABOVE THE SURFACE...DON/T EXPECT THE
SNOW SHOWERS TO BECOME TOO STRONG AND HAVE KEPT VISIBILITIES IN THE
MVFR TO VFR RANGE AT KCMX/KIWD. LOW LEVEL WINDS DO LOOK TO BACK
SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE TROUGH THAT WILL THEN SHIFT
WINDS BACK TO THE NORTHWEST AROUND DAYBREAK. THUS...HAVE KEPT VSBYS
A LITTLE HIGHER AT KIWD WITH THOSE BACKING WINDS. ONCE THAT WEAK
TROUGH MOVES THROUGH...WOULD THINK THAT LIGHT LAKE EFFECT WOULD MOVE
BACK INTO THE SITE. OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION
FOR KSAW...VFR WILL CONTINUE THROUGH THE PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 216 PM EST SUN DEC 28 2014
AS THE SURFACE TROUGH THAT SLID SOUTHEAST ACROSS LAKE SUPERIOR THIS
MORNING CONTINUES SOUTHEAST THROUGH THE LOWER GREAT
LAKES...PERSISTENT NORTHWEST WINDS OF 15-25KTS ARE EXPECTED OVER
THE LAKE THROUGH TUESDAY. THIS IS DUE TO THE AREA BEING BETWEEN A
STRONG HIGH MOVING INTO THE NORTHERN/CENTRAL PLAINS AND A LOW NEAR
HUDSON BAY. A SURFACE TROUGH WILL SWEEP ACROSS LAKE SUPERIOR ON
WEDNESDAY NIGHT AND TIGHTEN THE PRESSURE GRADIENT ACROSS THE LAKE.
THIS IS EXPECTED TO PRODUCE WESTERLY GALES OF 35-40KTS WEDNESDAY
INTO THURSDAY MORNING.
WITH MUCH COLDER TEMPERATURES MOVING OVER LAKE SUPERIOR OVER THE
NEXT SEVERAL DAYS...FREEZING SPRAY IS POSSIBLE FOR MUCH OF THE
PERIOD. WITH THE STRONGER WINDS TUESDAY NIGHT INTO THURSDAY...HEAVY
FREEZING SPRAY IS EXPECTED OVER MUCH OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
222 AM EST MON DEC 29 2014
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE
SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT
LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TODAY/...
930 PM UPDATE...
LAKE ENHANCED SNOW SHOWERS NOW ENTERING FAR NORTHERN ONEIDA COUNTY
AS HAD BEEN ANTICIPATED /IF ANYTHING...JUST A SMIDGE AHEAD OF
SCHEDULE/. THROUGH MIDNIGHT...ONLY A FEW TENTHS OF AN INCH SNOW
ACCUMULATION EXPECTED THERE MAINLY IN THE HIGHER TERRAIN NORTH OF
THE THRUWAY. FORECAST REMAINS ON TRACK.
625 PM UPDATE...
SMALL CLUSTER OF LIGHT SNOW SHOWERS HAS CARRIED ACROSS THE ONTARIO
PENINSULA...AND NOW OVER WESTERN TO CENTRAL LAKE ONTARIO WHILE
BECOMING LAKE ENHANCED. THIS ACTIVITY EN ROUTE TO ONEIDA COUNTY
MAINLY NORTH OF THE THRUWAY 03Z-06Z TO PERHAPS YIELD A VERY LIGHT
SKIFF OF SNOW. THEN MINOR LAKE EFFECT TO CONTINUE OVERNIGHT INTO
MONDAY MORNING VIA 270 FLOW GRADUALLY VEERING 290-300...WITH
ACCUMULATIONS VERY LIGHT IF ANY /AGAIN ON ORDER OF TENTHS OF AN
INCH/. FORECAST TWEAKED FOR SMALLER DETAILS...OVERALL IN FINE
SHAPE.
PREVIOUS DISCUSSION...
SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW
FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY
DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE
TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS
XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE
AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV
NRML FOR THE SEASON.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL
INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON
AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK
SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY
LYR FLOW WITHOUT ENHANCING THE LE.
LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A
BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE
THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY
TO BE OVER THE NRN THIRD OF THE FCST AREA.
BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE
SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER
ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG
MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND
THAT DVLPS NORTH OF THE FCST AREA.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
2 AM UPDATE...
FOLLOWED WPC GUIDANCE. LAKE EFFECT FAR NORTH TO START WITH THEN
POSSIBLE STORMS. STILL MUCH UNCERTAINTY ON THE FRIDAY TO SUNDAY
SCENARIO. MODELS DO NOT AGREE...BUT TREND TO A BIGGER PRECIP EVENT
FOR SUNDAY AND NOT FRIDAY OR SATURDAY. WPC HAS THE HIGHEST POPS ON
SATURDAY WITH A COLD FRONT MOVING SE THROUGH THE CWA AND MOISTURE
RUNNING NE AHEAD OF IT. AS STARTED BELOW COULD BE A MIXED PRECIP
EVENT. SUNDAY STORM WILL DEPEND ON THE TRACK WITH THE EURO WELL
SOUTH AND SNOW AND THE GFS TO THE WEST AND RAIN.
PREVIOUS DISCUSSION...
THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL
AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT
SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY.
A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL
SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION
MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER,
ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY,
TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL
CHANGE TO RAIN.
GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT
AREAS.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
1230 AM UPDATE...
MAINLY VFR CIGS AT AROUND 4K FT. WEAK LAKE EFFECT SNOW SHOWERS AND
CLOUDS. SYR AND RME MAY DROP TO MVFR CIGS AT TIMES DUE TO CLOUDS
BETWEEN NOW AND 12Z. ITH AND BGM MAY DROP TO MVFR CIGS MORE DUE TO
ELEVATION AND PROXIMITY TO CAYUGA LAKE AND ADDED MOISTURE.
WEST TO NORTHWEST WINDS AT 5 TO 10 KTS. ELM LIGHT AND VARIABLE AT
NIGHT.
OUTLOOK...
MON NGT TO WED NGT...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR
KRME/KSYR AND MAYBE KITH/KBGM...DUE TO LAKE EFFECT -SHSN.
OTHERWISE...VFR IS EXPECTED.
THU TO FRI...MVFR POSSIBLE IN SNOW WITH COLD FRONT IN NY.
AVP...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...DJP/TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1254 AM EST MON DEC 29 2014
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE
SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT
LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TODAY/...
930 PM UPDATE...
LAKE ENHANCED SNOW SHOWERS NOW ENTERING FAR NORTHERN ONEIDA COUNTY
AS HAD BEEN ANTICIPATED /IF ANYTHING...JUST A SMIDGE AHEAD OF
SCHEDULE/. THROUGH MIDNIGHT...ONLY A FEW TENTHS OF AN INCH SNOW
ACCUMULATION EXPECTED THERE MAINLY IN THE HIGHER TERRAIN NORTH OF
THE THRUWAY. FORECAST REMAINS ON TRACK.
625 PM UPDATE...
SMALL CLUSTER OF LIGHT SNOW SHOWERS HAS CARRIED ACROSS THE ONTARIO
PENINSULA...AND NOW OVER WESTERN TO CENTRAL LAKE ONTARIO WHILE
BECOMING LAKE ENHANCED. THIS ACTIVITY EN ROUTE TO ONEIDA COUNTY
MAINLY NORTH OF THE THRUWAY 03Z-06Z TO PERHAPS YIELD A VERY LIGHT
SKIFF OF SNOW. THEN MINOR LAKE EFFECT TO CONTINUE OVERNIGHT INTO
MONDAY MORNING VIA 270 FLOW GRADUALLY VEERING 290-300...WITH
ACCUMULATIONS VERY LIGHT IF ANY /AGAIN ON ORDER OF TENTHS OF AN
INCH/. FORECAST TWEAKED FOR SMALLER DETAILS...OVERALL IN FINE
SHAPE.
PREVIOUS DISCUSSION...
SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW
FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY
DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE
TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS
XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE
AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV
NRML FOR THE SEASON.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL
INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON
AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK
SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY
LYR FLOW WITHOUT ENHANCING THE LE.
LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A
BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE
THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY
TO BE OVER THE NRN THIRD OF THE FCST AREA.
BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE
SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER
ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG
MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND
THAT DVLPS NORTH OF THE FCST AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL
AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT
SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY.
A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL
SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION
MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER,
ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY,
TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL
CHANGE TO RAIN.
GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT
AREAS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
1230 AM UPDATE...
MAINLY VFR CIGS AT AROUND 4K FT. WEAK LAKE EFFECT SNOW SHOWERS AND
CLOUDS. SYR AND RME MAY DROP TO MVFR CIGS AT TIMES DUE TO CLOUDS
BETWEEN NOW AND 12Z. ITH AND BGM MAY DROP TO MVFR CIGS MORE DUE TO
ELEVATION AND PROXIMITY TO CAYUGA LAKE AND ADDED MOISTURE.
WEST TO NORTHWEST WINDS AT 5 TO 10 KTS. ELM LIGHT AND VARIABLE AT
NIGHT.
OUTLOOK...
MON NGT TO WED NGT...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR
KRME/KSYR AND MAYBE KITH/KBGM...DUE TO LAKE EFFECT -SHSN.
OTHERWISE...VFR IS EXPECTED.
THU TO FRI...MVFR POSSIBLE IN SNOW WITH COLD FRONT IN NY.
AVP...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...DJP
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS TULSA OK
1124 PM CST SUN DEC 28 2014
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
AREA OF LOW CLOUDS ACROSS CENTRAL AR AND FAR SERN OK CONTINUED TO
SLOWLY EXPAND WESTWARD AS OF 05Z. CARRIED SOME MVFR CIGS FOR A FEW
HOURS LATER TONIGHT AT MLC. MVFR VSBYS IN FOG ARE PROBABLE ACROSS
NWRN AR SITES 09-15Z AND POSSIBLE TUL/RVS...THE LATTER OF WHICH
ARE IN YESTERDAYS LIGHT SNOW FIELD THAT MELTED AWAY TODAY.
OTHERWISE...EXPECT VFR WITH VARIABLE HIGH CLOUDS. STRONG COLD
FRONT PUSHES THROUGH NERN OK SITES BY END OF PERIOD WITH MID
CLOUDS THICKENING AT THAT TIME.
&&
.PREV DISCUSSION... /ISSUED 908 PM CST SUN DEC 28 2014/
DISCUSSION...
THE DIFFERENCE FIELD BETWEEN THE 11.0 MICRON AND 3.9 MICRON
INFRA-RED SATELLITE DATA SHOWS LOW CLOUDS HOLDING OVER THE
SOUTHEAST TIP OF OKLAHOMA THIS EVENING. AS THE LOW-LEVEL FLOW
BECOMES LIGHT SOUTHEASTERLY THE CLOUDS SHOULD HAVE A TENDENCY TO
EXPAND NORTHWEST SOME AND HAVE SHOWN AN INCREASE IN CLOUDS LATER
TONIGHT IN FAR SOUTHEAST OKLAHOMA.
ALSO INTERESTING IS THE CURRENT SURFACE RELATIVE HUMIDITY FIELD
SHOWING READINGS AT JUST BEFORE 03Z IN THE UPPER 90S AT A FEW
MESONET SITES IN SOUTHEAST OKLAHOMA AND IN THE MID 90S OVER THE
OLD NARROW SNOW FIELD IN NORTHEAST OKLAHOMA. WITH LIGHT MOISTURE
ADVECTION DEVELOPING IN THE SOUTHEASTERLY SURFACE FLOW... THESE
AREAS WHERE THE HUMIDITY IS ALREADY HIGH WILL BE FAVORED FOR
PATCHY DENSE FOG FORMATION. NOT OVERLY CONFIDENT ABOUT THE
EVOLUTION OR COVERAGE...BUT IT IS WORTH SHOWING IN THE FORECAST
TEXT AND GRIDS. THE HRRR IS LIKELY OVERLY DRAMATIC...BUT IT SHOWS
VERY INTERESTING MESOSCALE TEMPERATURE...WIND AND HUMIDITY
EVOLUTIONS OVER THE OLD SNOW FIELD...WITH FOG ADVECTING NORTHWEST
SLOWLY LATER TONIGHT FROM THE OLD SNOW COVERED AREA.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...08
AVIATION...69
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1148 PM CST SUN DEC 28 2014
.AVIATION.../06Z TAF CYCLE/
ALL SITES ARE VFR SKC AS OF 29/06Z WITH LIGHT TO CALM WINDS. NWP
OUTPUT CONTINUES TO SUGGEST FOG DEVELOPMENT ALONG THE RIO GRANDE
VALLEY AND SPREADING EASTWARD TOWARDS KSAT 10-16Z TIME FRAME.
TRENDS HAVE BACKED AWAY FROM EASTWARD EXPANSION BUT FEEL KSSF HAS
SLIGHTLY GREATER CHANCE THEN KSAT. HAVE KEPT KAUS/KSAT VFR
THROUGH MORNING HOURS BUT HAVE PLACED HIGH END MVFR FOR KSSF FROM
10-15Z. HRRR OUTPUT AND RAP/NAM BUFR SOUNDINGS CONTINUE TO
INDICATE FOG DEVELOPMENT AT KDRT AND FORECAST FOLLOWS SUITE WITH
3SM VIS RESTRICTIONS 10-16Z DESPITE GFSLAMP GUIDANCE NOT
SUGGESTING FOG. EXPECT VFR CONDITIONS MONDAY AFTER FOG DISSIPATES
THROUGH MUCH OF THE OVERNIGHT INTO EARLY TUESDAY MORNING BEFORE
LOWER CLOUDS RETURN LATE MORNING TUESDAY. /ALLEN/
&&
.PREV DISCUSSION... /ISSUED 922 PM CST SUN DEC 28 2014/
UPDATE...
THE FORECAST HAS BEEN UPDATED FOR THE REMAINDER OF TONIGHT INTO
EARLY MONDAY MORNING. THE MAIN UPDATE WAS TO ADD A MENTION OF
PATCHY FOG ACROSS THE RIO GRANDE PLAINS AND SOUTHERN EDWARDS
PLATEAU. MINOR UPDATES HAVE ALSO BEEN MADE TO THE LATEST
TEMPERATURES...DEW POINTS AND WINDS TO ACCOUNT FOR RECENT
OBSERVATIONS. FINALLY...WE DID DECREASE OVERNIGHT LOW TEMPERATURES
SLIGHTLY ACROSS THE NORTHWESTERN HILL COUNTRY.
PREV DISCUSSION... /ISSUED 335 PM CST SUN DEC 28 2014/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
AN UPPER LEVEL TROUGH IS EXITING TO THE EAST OF SOUTH CENTRAL
TEXAS THIS AFTERNOON. SKIES HAVE CLEARED TO NEAR I-35. SKIES WILL
CLEAR ACROSS THE REMAINDER OF OUR AREA BY SUNSET. THIS SETS THE
STAGE FOR WIDESPREAD FREEZING TEMPERATURES BY MONDAY MORNING. WE
HAVE ISSUED A FREEZE WARNING FOR LATE TONIGHT INTO MONDAY MORNING
FOR OUR SOUTHERN TWO TIERS OF COUNTIES...EXCEPT FOR THE SOUTHWEST.
THESE AREAS HAVE NOT YET REACHED FREEZING THIS FALL/WINTER.
MEANWHILE...THE HILL COUNTRY AND ALONG THE ESCARPMENT ALREADY HAVE
SEEN FREEZING TEMPERATURES THIS WINTER SEASON WHILE THE RIO GRANDE
PLAINS WILL FALL TO JUST ABOVE FREEZING. SEE OUR SPECIAL WEATHER
STATEMENT FOR DETAILS FOR THOSE AREAS. A BRIEF WARM UP IS EXPECTED
ON MONDAY ON SOUTH TO SOUTHWEST WINDS. LATE MONDAY NIGHT ANOTHER
COLD FRONT IS EXPECTED TO ENTER THE FAR NORTHERN HILL COUNTRY.
TEMPERATURES SHOULD STAY ABOVE FREEZING MONDAY NIGHT ON MIXING
ALONG AND AHEAD OF FRONT.
LONG TERM (TUESDAY THROUGH SUNDAY)...
THE COLD FRONT WILL SURGE ACROSS THE REMAINDER OF SOUTH CENTRAL
TEXAS TUESDAY MORNING. HIGH TEMPERATURES WILL BE REACHED LATE
MORNING TO MIDDAY AS CLOUDS INCREASE DUE TO MOIST SOUTHERLY FLOW
RIDING OVER COLD ADVECTION IN THE LOWER LEVELS. MODELS ARE IN
BETTER AGREEMENT ON THE PATTERN EVOLUTION IN THE LONG TERM.
ALTHOUGH...SOME DISAGREEMENT REMAINS AND THE FORECAST MAY CHANGE
OVER THE NEXT FEW DAYS. AN UPPER UPPER LEVEL TROUGH DROPPING DOWN
THE WEST COAST ON TUESDAY CLOSES OFF OVER SOUTHERN CALIFORNIA ON
WEDNESDAY INTO THURSDAY AND THEN OPENS UP AND MOVE ACROSS TEXAS
FRIDAY INTO EARLY SATURDAY. ISENTROPIC LIFT DEVELOPS TUESDAY NIGHT
INTO WEDNESDAY LEADING TO AREAS OF LIGHT RAIN INITIALLY ALONG THE
RIO GRANDE...THEN SPREADING ACROSS THE REMAINDER OF THE AREA.
PERIODS OF LIGHT TO OCCASIONALLY MODERATE RAIN OR SHOWERS WILL
CONTINUE THROUGH FRIDAY NIGHT. THERE IS A THREAT FOR WINTER TYPE
PRECIPITATION DURING THE LATE NIGHT INTO MORNING HOURS MAINLY FOR
PARTS OF THE HILL COUNTRY TUESDAY NIGHT THROUGH THURSDAY (NEW
YEARS DAY) MORNING. FORECAST SOUNDINGS SHOW A THICK LAYER ABOVE
FREEZING DEVELOPING ON TOP OF A SHALLOW SUBFREEZING BOUNDARY
LAYER. FREEZING RAIN IS THE LIKELY WINTER TYPE PRECIPITATION THAT
IS EXPECTED WHERE TEMPERATURES DROP BELOW FREEZING. HOWEVER...NO
SIGNIFICANT ICE ACCUMULATIONS ARE EXPECTED. SHOULD THE RAIN BECOME
MORE CONVECTIVE...THEN SOME SLEET MAY BE POSSIBLE OVER A GREATER
AREA. FINALLY...THERE MAY BE A THREAT OF LIGHT SNOW ACROSS WESTERN
EDWARDS PLATEAU PRIOR TO THE DEVELOPMENT OF THE WARM LAYER ALOFT.
BY THURSDAY AFTERNOON...THE LOWER LEVELS WARM ABOVE FREEZING WITH
ONLY A COLD RAIN EXPECTED. AS THE UPPER LOW APPROACHES AND MOVES
ACROSS...SOME THUNDERSTORMS ARE POSSIBLE DUE TO ELEVATED
INSTABILITY THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE RAINS END FROM
WEST TO EAST BY SATURDAY MORNING. FAIR SKIES AND MUCH WARMER
DAYTIME TEMPERATURES ARE EXPECTED NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 32 61 39 46 36 / 0 0 - 10 10
AUSTIN BERGSTROM INTL AIRPORT 25 60 35 46 36 / 0 0 - 10 10
NEW BRAUNFELS MUNI AIRPORT 29 61 36 48 38 / 0 0 - 10 10
BURNET MUNI AIRPORT 29 61 36 43 32 / 0 0 - 10 20
DEL RIO INTL AIRPORT 34 62 40 56 37 / 0 0 - 10 30
GEORGETOWN MUNI AIRPORT 28 60 35 44 34 / 0 0 - 10 10
HONDO MUNI AIRPORT 28 62 35 51 38 / 0 0 - 10 20
SAN MARCOS MUNI AIRPORT 29 61 36 47 37 / 0 0 - 10 10
LA GRANGE - FAYETTE REGIONAL 31 59 40 50 39 / 0 0 - 10 10
SAN ANTONIO INTL AIRPORT 32 62 39 49 38 / 0 0 - 10 20
STINSON MUNI AIRPORT 32 61 39 51 39 / 0 0 - 10 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 9 AM CST MONDAY FOR THE FOLLOWING COUNTIES:
ATASCOSA...DE WITT...FAYETTE...FRIO...GONZALES...KARNES...LAVACA...
UVALDE...WILSON...ZAVALA.
&&
$$
MESOSCALE/AVIATION...15
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1138 PM CST SUN DEC 28 2014
.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION SECTION...
&&
.AVIATION...
SATELLITE IMAGERY SHOWS THAT CLEARING LINE HAS STOPPED ITS
EASTWARD PROGRESS JUST WEST OF KSGR/KCXO/KUTS. SO WILL KEEP CIGS
VFR FOR KCLL BUT MAINLY IFR FOR ALL OTHER TERMINALS. STILL
ANTICIPATE SOME LIFR CIGS TO DEVELOP WITH CLOSE T/TD SPREADS.
LATEST TRENDS IN HRRR HOLD ONTO IFR CIGS AND EVEN SPOTTY LIFR.
LOOK FOR CIGS TO IMPROVE LATE MORNING INTO THE AFTERNOON TOMORROW.
MAY GET VFR AREA WIDE IN THE EVENING INTO TOMORROW NIGHT. HIGH
PRESSURE OVER THE AREA WILL KEEP WINDS LIGHT AND VARIABLE.
39
&&
.PREV DISCUSSION... /ISSUED 857 PM CST SUN DEC 28 2014/
DISCUSSION...
HIGH PRESSURE WILL BUILD OVERHEAD AS THE SHORTWAVE TROUGH MOVES
EASTWARD OF THE FORECAST AREA. EXPECT CLEARING CONDITIONS AND
COLDER TEMPERATURES OVERNIGHT TONIGHT. FORECAST SOUNDINGS AND
GUIDANCE ALSO IS FORECASTING PATCHY FOG. BECAUSE OF THE CLEARING
SKIES AND THE ABUNDANCE OF SURFACE MOISTURE DUE TO THE RAINFALL...
PATCHY FOG DOES LOOK MORE LIKELY.
UPDATE TO TAKE OUT RAINFALL CHANCES AND TO ADD PATCHY FOG
OVERNIGHT TONIGHT AND ENDING MID MORNING MONDAY.
40
PREV DISCUSSION... /ISSUED 553 PM CST SUN DEC 28 2014/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
LATEST RADAR TRENDS HAS RAIN ASSOCIATED WITH SHORT WAVE TROUGH
MOVING OUT OF THE AREA. THIS SHOULD ALLOW FOR VSBY/CIGS TO IMPROVE
THE NEXT SEVERAL HRS BUT STILL QUITE A BIT OF MOISTURE TRAPPED IN
COLD AIRMASS. SATELLITE IMAGERY SHOWS CLEARING LINE APPROACHING
KCLL FROM THE WEST. THIS MAY PUSH FAR ENOUGH EAST TO ALLOW FOR
IMPROVING CIGS BUT NOT SURE HOW FAR WEST IT WILL MOVE.
KCLL...THINK THERE SHOULD BE CLEARING FOR MOST OF THE NIGHT BUT
NOT SEEING MODELS INDICATE IF CIGS/VSBY FILL BACK IN THROUGH THE
MORNING WITH RADIATIONAL COOLING. WILL KEEP TAF VFR.
KUTS/KCXO/KIAH/KHOU/KSGR...WITH RAIN MOVING OUT EXPECT VSBY/CIGS
TO IMPROVE SOME. MAY BREAK OUT OF OVC IFR CONDITIONS TO BKN BUT
STILL POSSIBLE FOR IFR TO HOLD ON THROUGH MORNING. CONCERNED
CLEARING COULD OCCUR AS DRIER AIR TRIES TO MIX INTO THE AREA SO
WILL NEED TO WATCH FOR THAT AND MAY GET CIGS TO GO SCT FROM 03Z-
09Z. HRRR 19-21Z RUNS SHOW THIS TREND IN CIGS SCATTERING OUT BUT
THEN GET LOW IFR TO BUILD BACK IN FROM 09Z TO 15Z. TAFS WILL BE
GEARED TOWARDS THESE LOWER CIGS IN THE MORNING AND THEN SLOWLY
GOING IFR/MVFR WITH VFR BY LATE AFTERNOON TOMORROW. WITH HIGH
PRESSURE BUILDING IN...LIGHT WINDS EXPECTED.
KLBX/KGLS...MORE LIKELY THAT CLEARING WILL NOT OCCUR FROM THE WEST
FOR THESE TERMINALS SO HAVE MORE CONFIDENCE IN IFR CIGS HOLDING
THROUGH THE NIGHT. ALSO POSSIBLE FOR CIGS TO DROP IN THE MORNING
TO LOW IFR AS THERE WILL NOT BE ANY DRIER AIR TO MIX AS COMPARED
TO MORE INLAND SIGHTS. OTHERWISE TRENDS SHOULD BE SIMILAR TO
INLAND TERMINALS WITH IFR UNTIL LATE MORNING AND THE MVFR IN THE
AFTERNOON.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 33 58 38 51 35 / 10 0 0 10 10
HOUSTON (IAH) 36 59 42 57 38 / 10 0 0 10 10
GALVESTON (GLS) 43 57 48 56 44 / 10 0 0 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1105 PM CST SUN DEC 28 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 200 PM CST SUN DEC 28 2014
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE NORTHWESTERN
U.S. AND BRITISH COLUMBIA...A COLLECTION OF WEAK SHORTWAVES OVER
WYOMING AND NEBRASKA AND AN UPPER LOW OVER NORTHERN ONTARIO. DESPITE
A MAINLY ZONAL FLOW COMING ACROSS THE FORECAST AREA...A COLD FRONT
WAS EVIDENT AT THE SURFACE DROPPING SOUTH INTO THE AREA. THIS FRONT
EXTENDED FROM NORTHERN LOWER MI TO LA CROSSE TO SIOUX CITY IA. LOW
CLOUDS WITH A FEW FLURRIES WERE EVIDENT IN A 100 MILE WIDTH ZONE
BEHIND THE FRONT...WHILE SKIES WERE MAINLY SUNNY AHEAD OF IT. 925MB
TEMPS OF -6 TO -10C AND SUN HAS ALLOWED TEMPERATURES TO MOSTLY CLIMB
INTO THE 20S WITH A FEW NEAR 30 READINGS IN FAR SOUTHWEST WISCONSIN.
COLDEST READINGS HAVE BEEN OVER THE NORTHWEST 1/3 OF THE AREA WITH
MORE SNOW AND BEING FIRST TO EXPERIENCE THE FROPA. MUCH COLDER AIR
TRYING TO SINK SOUTH BEHIND THE FRONT WITH 925MB TEMPS IN THE -15 TO
-20C RANGE OVER MUCH OF NORTH DAKOTA INTO NORTHERN MN.
THE MAIN FEATURE OF INTEREST FOR THE SHORT TERM IS THE COLLECTION OF
WEAK SHORTWAVES OVER WYOMING AND NEBRASKA. MODELS ARE IN GOOD
AGREEMENT BRINGING THESE SHORTWAVES ACROSS IOWA AND SOUTHERN
PORTIONS OF THE FORECAST AREA LATE TONIGHT INTO MONDAY MORNING. WITH
THESE SHORTWAVES COMES INCREASING MID LEVEL FRONTOGENESIS...MOSTLY
IN THE WAKE OF THE CURRENT COLD FRONT DROPPING SOUTH THROUGH THE
FORECAST AREA. PROBLEM IS THAT AT THE TIME OF THE BEST MID LEVEL
LIFT...THERE IS ENOUGH DRY AIR BELOW THE MID CLOUDS TO ABSORB MUCH
OF THE SNOW PRODUCTION. WHEN THAT DRY AIR MOSTLY SATURATES...THE
LIFT IS GONE. THEREFORE...A MENTION OF FLURRIES AS THE PREVIOUS
FORECAST HAD SEEMS REASONABLE. MOST 28.12Z GUIDANCE OF QPF CONTINUES
TO PRODUCE A DRY FORECAST TOO.
COLD ADVECTION BEHIND THE COLD FRONT PASSAGE WILL BE THE MAIN FACTOR
IN DROPPING TEMPERATURES TONIGHT...SINCE CLOUDS SHOULD BE IN PLACE
FOR MOST LOCATIONS. 925MB TEMPS FALL TO -10C SOUTH TO -15C NORTH...
WHICH SHOULD ALLOW TEMPERATURES TO DROP INTO THE SINGLE DIGITS NORTH
TO NEAR 20 SOUTH. THE COLDEST READINGS ARE EXPECTED IN TAYLOR/CLARK
COUNTIES WHERE SOME CLEARING IS POSSIBLE THIS EVENING BEFORE
MID/HIGH CLOUDS OVERSPREAD. FURTHER 925MB TEMP COOLING TAKES PLACE
ON MONDAY DUE TO PERSISTENT NORTHERLY FLOW. READINGS DROP TO -13C
SOUTH TO -17C NORTH...WHICH MEANS HIGHS WILL STRUGGLE TO CLIMB MUCH
THAN A FEW DEGREES ABOVE THE LOWS TONIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 200 PM CST SUN DEC 28 2014
THE MAIN STORY MONDAY NIGHT THROUGH TUESDAY NIGHT IS THE COLD. ALL
MODELS CONTINUE TO DROP A 1050-1060MB HIGH SOUTHWARD ALONG THE LEE
SIDE OF THE ROCKIES DURING THIS TIME...WITH COLD ADVECTION
DOWNSTREAM OF THE HIGH OVER THE FORECAST AREA. 925MB TEMPS FALL TO
-16 TO -19C BY 12Z TUESDAY AND TO AROUND -20C BY 06Z WEDNESDAY. MUCH
OF THE TIME PERIOD SHOULD BE MOSTLY CLEAR...OUTSIDE OF SOME PASSING
CLOUDS TUESDAY AFTERNOON AND EVENING ASSOCIATED WITH A SHORTWAVE
TROUGH OF ARCTIC ORIGIN MOVING THROUGH. THE SOUTHEAST HALF OF THE
FORECAST AREA WILL STAY WARMER DUE TO THE FACT OF NO SNOW ON THE
GROUND...BUT STILL EXPECT CHILLY READINGS...ESPECIALLY TUESDAY NIGHT
WITH THE COLDEST AIR IN PLACE. A PERSISTENT NORTHWEST BREEZE SHOULD
EXIST SINCE WE ARE NOT UNDER THE CENTER OF THE HIGH...THEREFORE...
WIND CHILLS BECOME A FACTOR. ADVISORIES ARE LIKELY TO BE NEEDED BOTH
NIGHTS...PARTICULARLY OVER NORTH CENTRAL WI AND POSSIBLY PORTIONS OF
SOUTHEAST MN AND NORTHEAST IA TOO.
SOME MODERATION TAKES PLACE WEDNESDAY INTO THURSDAY / NEW YEARS EVE
AND DAY / IN RESPONSE TO A POTENT SHORTWAVE TROUGH DIGGING INTO
NORTHERN ONTARIO AND LAKE SUPERIOR. HOWEVER...THIS MODERATION TAKES
PLACE AT THE EXPENSE OF HIGHER WINDS...WHICH MEANS A PERSISTENT WIND
CHILL FACTOR. FIRST...THE WESTERLY WINDS ADVECT DOWNSLOPED AIR OFF
THE ROCKIES TOWARDS THE FORECAST AREA...BOOSTING 925MB TEMPS TO
AROUND -14C BY 00Z THU AND -8 TO -10C BY 00Z FRI. THESE READINGS
SHOULD HELP BRING HIGHS BACK UP INTO THE TEENS ON WEDNESDAY AND
MOSTLY INTO THE 20S ON THURSDAY. NOW REGARDING THE WINDS...925MB
SPEEDS ARE PROGGED TO INCREASE TO THE 35 TO 45 KT RANGE AT 00Z THU
BEFORE RELAXING SOME FOR DURING THE DAY THURSDAY. WITH PLENTY OF SUN
ON WEDNESDAY...WE SHOULD SEE SOME GOOD MIXING OF THOSE WINDS. RIGHT
NOW IT APPEARS GUSTS MAY TOP OUT AROUND 30 KT...HIGHEST IN SOUTHEAST
MN...BUT WORTH MONITORING OVER THE NEXT FEW DAYS TO SEE IF THESE END
UP HIGHER. SOMETHING ELSE TO MONITOR ON THURSDAY IS POSSIBLE LIGHT
SNOW AS A COLD FRONT AND SHORTWAVE TROUGH DROP THROUGH THE NORTHERN
PORTION OF THE FORECAST AREA. HAVE ADDED SOME CHANCE POPS TO
LOCATIONS NORTH OF I-90.
FOR FRIDAY INTO SATURDAY...WE NEED TO WATCH CLOSELY THE EVOLUTION
AND TRACK OF AN UPPER LOW THAT COMES OUT OF THE SOUTHWESTERN U.S..
THIS UPPER LOW...FORMED BY THE CURRENT STRONG SHORTWAVE DIVING SOUTH
THROUGH THE NORTHWESTERN U.S....IS PRESENTLY PROGGED TO GET LIFTED
THROUGH MISSOURI AND INTO LOWER MI ON SATURDAY. SOME WARM ADVECTION
SNOW COULD BEGIN TO APPROACH THE REGION AS EARLY AS LATE FRIDAY WELL
DOWNSTREAM OF THIS UPPER LOW...OR FROM A FRONTOGENESIS BAND TRACKING
ACROSS THE NORTHERN U.S.. HOWEVER...FRIDAY NIGHT INTO SATURDAY SEEM
TO BE THE BETTER CHANCES IN SEEING A COLD CONVEYOR BELT BAND OF SNOW
TRACK ACROSS THE FORECAST AREA FROM THE UPPER LOW. IF THIS SYSTEM
TRACKS FARTHER NORTHWEST...MAY END UP WITH AN ADVISORY LEVEL SNOW.
NOTE THAT THE 28.12Z ECMWF/UKMET/CANADIAN PRESENT A MUCH SLOWER IDEA
WITH THE UPPER LOW...RESULTING IN A MUCH DRIER SCENARIO...THUS
PLENTY OF UNCERTAINTY AND ONLY 30-40 PERCENT PRECIPITATION CHANCES.
POST THE SATURDAY SYSTEM...A STRONG SURGE OF ARCTIC AIR LOOKS POISED
TO IMPACT THE REGION FOR SUNDAY INTO EARLY NEXT WEEK. IT COULD BE
NEARLY AS COLD AS THE JANUARY 5-7TH 2014 ARCTIC OUTBREAK...AND JUST
HAPPENS TO BE THE SAME DATES. THE 28.12Z MODEL CYCLE DEPICTS THE GFS
COLDER WHILE THE ECMWF WAS WARMER AND A BIT MORE DELAYED...WAITING
UNTIL MONDAY TO DRIVE THE COLD AIR IN. NEEDLESS TO SAY...STAY
TUNED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN DEC 28 2014
AREAS OF 1 KFT CLOUDS HANGING ACROSS SOUTHWEST MN LATE THIS
EVENING...BUT MESO MODELS ARE ADAMANT THAT THESE WILL STAY WEST OF
KRST. INSTEAD...HIGH LEVEL CLOUDS ARE EXPECTED TO CONTINUE TO FILTER
ACROSS THE REGION TONIGHT/MONDAY...STAYING VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
524 AM MST MON DEC 29 2014
.UPDATE...
ISSUED AT 520 AM MST MON DEC 29 2014
BASED ON LAST COUPLE OF RUNS OF THE HRRR....WHICH SHOW GREATEST
SNOWFALL POTENTIAL OVER SE PUEBLO COUNTY AND PORTIONS OF THE
PLAINS N OF THE ARKANSAS...HAVE DECIDED TO ADD THESE COUNTIES TO
THE SNOW ADVISORY. HRRR SHOWS QPF MAXES OVER SRN PUEBLO COUNTY
AND PROWERS COUNTY. THIS MATCHES OTHER MODEL TRENDS AS WELL. SRN
EL PASO LOOKS LIKE IT WILL BE LEFT OUT OF THE HEAVIER SNOW
BANDS...SO WILL LEAVE IT OUT OF THE ADVISORY FOR NOW. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM MST MON DEC 29 2014
...FRIGID AIR HEADED OUR WAY ALONG WITH SOME SNOW...
THE COLD FRONT IS NOW PUSHING SWD THROUGH NE CO AND WILL CONTINUE TO
ADVANCE TO THE SOUTH THIS MORNING. THE FRONT SHOULD BE OVER THE
PALMER DVD BY 15Z AND THEN CHARGE SWD ALONG ALL OF OUR ERN PLAINS BY
18Z. SINCE THE PRECIP WILL ACCOMPANY THE FRONT...HAVE PUSHED BACK
TIMING OF POPS A BIT BUT BY 18Z THERE SHOULD BE FAIRLY GOOD COVERAGE
OF SNOW OVER OUR AREA. THE COLD AIR WILL BE DEEP ENOUGH TO SPILL INTO
THE SAN LUIS VALLEY TONIGHT...SO EVERYONE WILL GET A DOSE OF THE
FRIGID CONDITIONS. TEMPS TODAY WILL START OUT IN THE TEENS AND
SINGLE DIGITS...AND HIGH TEMPS WILL BE REALIZED EARLY AS STRONG CAA
WILL BE THE RULE THROUGH TODAY. MAY NOT GET OUT OF THE TEENS OVER
THE NRN I-25 CORRIDOR...AND REST OF THE SE PLAINS WILL ONLY BE IN THE
20S.
MODELS HAVE BEEN EXTREMELY CONSISTENT BOTH IN TIME AND ACROSS THE
BOARD IN TERMS OF EXPECTED QPF FROM THIS EVENT. HIGH SNOW-LIQUID
RATIOS MAY PUSH THINGS A BIT HIGHER THAN FORECAST...BUT IN GENERAL
THE MODEL GUIDANCE IS SHOWING 3 TO 6 INCH TOTALS FOR THE LOWLANDS
AND 6 TO 8 INCH TOTALS FOR THE MOUNTAINS. HAVE ADDED FREMONT COUNTY
AND THE ARKANSAS RIVER CANYON TO OUR SNOW ADVISORIES...ALONG WITH THE
NORTHERN SAN LUIS VALLEY...WHERE THE MODELS HAVE CONSISTENTLY BEEN
SHOWING DECENT SNOW AMOUNTS FOR TONIGHT. ALSO EXTENDED THE CENTRAL
MTS ADVISORY THROUGH TUESDAY MORNING AS ADDITIONAL ACCUMULATIONS
LOOK LIKELY THERE. SNOW AMOUNTS EVERYWHERE LOOK TO BE BORDERLINE
ADVISORY LEVELS. FROM AN IMPACT PERSPECTIVE...IT WILL BE A TWO EDGED
SWORD SINCE THERE WILL STILL BE PLENTY OF HOLIDAY TRAFFIC BUT WITH
THE HIGH SNOW-LIQUID RATIOS AND COLD AIR...ROAD CONDITIONS MAY NOT
BE QUITE AS BAD. GIVEN THE POTENTIAL FOR SLIGHTLY HIGHER SNOW
TOTALS...AN ADVISORY LOOKS LIKE THE BEST COURSE OF ACTION AT THIS
TIME. REMAINING ZONES/AREAS THAT WILL REQUIRE CLOSE ATTENTION ARE
THE UPPER ARKANSAS VALLEY...IF COLD AIR CONTINUES TO PUSH TO THE
WEST THIS EVENING...AND THE HIGHER TERRAIN OF PUEBLO COUNTY OVER SRN
AND WRN PORTIONS OF THE ZONE.
TONIGHT...LIGHT SNOW WILL CONTINUE AND WILL SPREAD OUT EWD TOWARD
THE KS BORDER. AMOUNTS COULD APPROACH LOW-END ADVISORY LEVELS BY TUE
MORNING. H7 TEMPS CONTINUE TO PLUMMET TO NR MINUS 23 DEGREES...WHICH
TYPICALLY ONLY HAPPENS A COUPLE TIMES EACH WINTER. THE ONLY THING
THAT WILL KEEP THE LOWER ARKANSAS VALLEY FROM HITTING LOWS MINUS 20
DEGREES OR LOWER WILL BE THE EXTENSIVE CLOUDS AND LIGHT SNOW. THIS
WILL SERVE TO KEEP US ON THE `WARM` SIDE...ONLY ZERO TO MINUS 10
DEGREES BY EARLY TUE MORNING. THERE WILL BE BORDERLINE WIND-CHILL
ADVISORY READINGS OVER THE MTS...SAN LUIS VALLEY...AND PIKES PEAK
REGION BUT IT LOOKS FAIRLY SPOTTY AT THIS TIME SO WILL HOLD OFF ON
ISSUING ANY WIND CHILL ALERTS. THE COLDEST AIR STILL LOOKS TO BE ON
TUESDAY AND TUE NIGHT. SO...BREAK OUT LOTS OF LAYERS AND PREPARE FOR
THE COLD! ROSE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 312 AM MST MON DEC 29 2014
...VERY COLD TUESDAY...THEN WHERE DOES THE UPPER LOW GO LATE IN THE
WEEK?...
TUESDAY...
IT WILL BE VERY COLD ACROSS THE REGION. IT APPEARS NOW THAT ALL
AREAS ON THE PLAINS WILL ONLY SEE HIGH TEMPS IN THE POSITIVE
SINGLE DIGITS. AREAS ON THE PALMER DIVIDE MAY SEE A FEW MAX TEMPS
IN THE NEGATIVE SINGLE DIGITS. I SHOULD NOTE THAT MOS IS A FEW
DEGREES COOLER THAN CURRENT GRIDS...HOWEVER SPC PLUME VIEWER
PRODUCTS LEAN MORE TOWARDS CURRENT NDFD TEMPS...AND CURRENT
FORECASTED HIGH TEMPS MATCH UP WITH SURROUNDING WFO/S. IT WILL BE
CLOUDY OVER THE PLAINS TUESDAY AND SNOW IS LIKELY MOST IF NOT ALL
LOWER ELEVATIONS...ESPECIALLY IN THE MORNING. IT APPEARS THE SNOW
THAT FALLS ON THE PLAINS WILL BE LIGHT...WITH ONLY AN INCH OR TWO
OF NEW SNOW POSSIBLE DURING THE DAY TUESDAY. HIGHER AMOUNTS WILL
BE POSSIBLE ON THE EAST SLOPES OF THE S MTNS.
WIND CHILL READINGS TUESDAY WILL BE THE MAIN CONCERN AS I EXPECT
THESE VALUES WILL RANGE BETWEEN -10 AND -20F MOST OF THE DAY.
MTNS AND VALLEYS WILL SEE SOME LIGHT SNOW...ESPECIALLY C MTNS.
ACCUMS SHOULD BE LIGHT. THE ARCTIC AIR WILL LIKELY GET INTO THE
UPPER ARK RVR VALLEY...HOWEVER THE SAN LUIS VALLEY WILL NOT SEE
THE BRUNT OF THE COLD AIR...AND MAX TEMPS IN THE SLV SHOULD BE IN
THE UPPER TEENS.
TUESDAY NIGHT...
VERY COLD TEMPERATURES ARE CERTAIN. HOW COLD IS THE QUESTION. MIN
TEMPS WILL BE DEPENDENT ON HOW MUCH CLOUDINESS (OR LACK THEREOF) WE
HAVE OVER THE REGION. IT WILL ALSO BE DEPENDENT ON SNOW COVER. FOR
NOW THE NDFD MIN TEMPS RANGE BETWEEN -5 TO -15F OVER THE PLAINS.
IF IT CLEARS OUT AND THERE IS WIDESPREAD SNOW COVER...THEN THESE
TEMPS COULD BE 5 TO 10F COLDER THAN CURRENT FORECASTED LOWS.
WEDNESDAY...
WE START TO MODERATE ACROSS THE REGION...ALTHOUGH IT STILL WILL BE
COLD. I DO NOT EXPECT ANY LOCATIONS IN THE CWA TO GET ABOVE FREEZING
THIS DAY. WARMEST TEMPS WILL LIKELY OCCUR IN THE MID ARK RVR VALLEY
(SALIDA TO CANON CITY) WHERE TEMPS WILL GET INTO THE MID 20S. I
EXPECT THE PLAINS WILL PRIMARILY BE IN THE TEENS WITH A 20S JUST
EAST OF THE MTNS. EXCEPT FOR SOME SHOWERS ALONG THE CONTDVD...IT
WILL BE DRY.
THURSDAY INTO THE WEEKEND...
CONCERN TURN TOWARDS THE CLOSED LOW THAT WILL BE N ARIZ THURSDAY
MORNING. LATEST GUIDANCE IS INDICATING A BIT MORE FAVORABLE TRACK
FOR THE SOUTHERN TIER OF THE FCST AREA...ESPECIALLY THE SAN JUANS
FOR LATE WED INTO EARLY FRIDAY. HAVE INCREASED POPS OVER THE SAN
JUAN REGION THU AND FRI...AND HAVE EXTENDED POPS EASTWARD ACROSS THE
S TIER OF THE PLAINS FRIDAY INTO SATURDAY.
OVER THE REMAINDER OF THE REGION...TEMPS WILL MODIFY WITH TEMPS
RETURNING TO SLIGHTLY BELOW NORMAL TEMPERATURES (~40F PLAINS)
/HODANISH
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 312 AM MST MON DEC 29 2014
AN ARCTIC FRONT WILL PUSH SOUTHWARD INTO SE CO BETWEEN 15 AND 18Z
THIS MORNING. THIS WILL LEAD TO A PROLONGED PERIOD OF MVFR TO IFR
CONDITIONS...AND OCCASIONAL LIFR CONDITIONS...THROUGH TUESDAY. KCOS
AND KPUB WILL SEE THESE CONDITIONS DEVELOP FROM 16-18Z AS LIGHT SNOW
BECOMES MORE WIDESPREAD AND PERSISTENT THROUGH THIS AFTERNOON. WINDS
WILL BE MODERATE FROM THE NE DURING THIS PERIOD. KALS WILL SEE
CONDITIONS DETERIORATE A BIT LATER TODAY AS IT WILL TAKE A WHILE FOR
THE COLD AIR TO SPILL OVER INTO THE SAN LUIS VALLEY...BUT SIMILAR
MVFR-IFR CONDITIONS ARE EXPECTED IN THE HIGH VALLEYS OVERNIGHT INTO
TUE MORNING. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 AM MST
TUESDAY FOR COZ065-069-072>080-083-086>089-093-095>098.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ058-060.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ081-082-
084.
&&
$$
UPDATE...ROSE
SHORT TERM...ROSE LONG TERM...HODANISH
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
930 AM EST MON DEC 29 2014
.DISCUSSION...
...HIGH RISK OF RIP CURRENTS ONCE AGAIN AT THE BEACHES...
...NEAR RECORD HIGH TEMPERATURES TODAY...
MILD WX PATTERN CONTINUES AS A WEAK FRONTAL TROF OVER THE
CENTRAL/ERN GOMEX CREEPS TOWARD THE FL PENINSULA. PROGRESS WILL BE
SLOW AS THE RUC ANALYSIS SHOWS A DEEP HIGH PRES RIDGE AHEAD OF THE
FRONT EXTENDING FROM THE YUCATAN PENINSULA ACRS NRN CUBA AND THE
CENTRAL BAHAMAS. MORNING RAOBS AT KJAX/KTBW SHOW PWATS ARND 1.0"
INCREASING TO 1.3" AT KMFL...SHARP SUBSIDENCE INVERSIONS THRU THE
H90-H75 LYR...AND DEEP S/SWRLY FLOW THRU THE COLUMN. LCL CONVERGENCE
ZONE BTWN THE TREASURE COAST AND THE NRN BAHAMAS HAS ALLOWED ISOLD
SHRAS TO FORM S OF VERO BEACH...BUT THE PREVAILING SRLY STEERING
FLOW HAS KEPT MOST OF THESE OFFSHORE.
ASIDE FROM BRIEF PDS OF LIGHT RAIN ALONG THE TREASURE COAST...FCST
WILL REMAIN DRY. SKIES WILL REMAIN PTLY/MSUNNY WITH STEADY S/SW
WINDS PUSHING AFTN MAX TEMPS TO WITHIN A DEG OR TWO OF THEIR DAILY
RECORDS. FRNTL BNDRY OVER THE PANHANDLE WILL APPROACH THE BIG BEND
REGION BY SUNSET...BUT WILL REMAIN TOO FAR TO THE NW TO ALLOW ANY
PRECIP TO DVLP UNTIL AFT MIDNIGHT.
A PERSISTENT LONG PERIOD E/NE SWELL WILL DIMINISH TODAY BUT WILL
CONTINUE TO PRODUCE A HIGH RIP CURRENT THREAT ALONG AREA BEACHES
THIS AFTN.
&&
.AVIATION...THRU 30/12Z
SFC WNDS: THRU 30/02Z...S/SW BTWN 6-9KTS...BCMG S/SE CSTL SITES S OF
KMLB AFT 28/18Z. BTWN 30/02Z-30/04Z...S/SW 3-5KTS. AFT 30/04Z...W/SW
AOB 3KTS.
VSBYS/WX: THRU 30/00Z...S OF KVRB ISOLD MVFR SHRAS. BTWN
30/00Z-30/04Z...VFR. BTWN 30/04Z-30/08Z...S OF KMLB-KISM AREAS MVFR
BR/LCL LIFR FG...CONTG THRU 30/12Z. AFT 30/08Z...SLGT CHC MVFR
-SHRAS N OF KTIX-KISM.
CIGS: THRU 30/00Z...AREAS BTWN FL020-030 S OF KVRB IN ISOLD SHRAS.
BTWN 30/00Z-30/04Z...BTWN FL040-060. AFT 30/04Z...N OF KMLB-KISM
BTWN FL020-030 WITH AREAS BLO FL010...S OF KMLB-KISM BTWN FL040-060
WITH AREAS BTWN FL020-030.
&&
.MARINE...
RIDGE AXIS EXTENDING FROM THE YUCATAN PENINSULA ACRS NRN CUBA THRU
THE CENTRAL BAHAMAS WILL INTERACT WITH A WEAK FRONTAL TROF OVER THE
CENTRAL/ERN GOMEX TO GENERATE A GENTLE TO MODERATE A/SWRLY BREEZE
THRU MIDNIGHT...BCMG LIGHT TO GENTLE W/SW THRU THE PREDAWN HRS AS
THE TROF PRESSES INTO THE N FL PENINSULA. PERSISTENT LONG PD SWELL
WILL CONTINUE BEGIN TO DAMPEN OUT AS WINDS SHIFT TO THE MORE WRLY
COMPONENT...SEAS 2-3FT NEARSHORE AND 3-4FT OFFSHORE THRU SUNSET BCMG
2-3FT AREAWIDE AFT SUNSET.
&&
.CLIMATE...
RECORD HIGHS FOR TODAY 29 DECEMBER...
DAYTONA BEACH 83/1946
ORLANDO 84/2007
MELBOURNE 84/1973
VERO BEACH 85/2012
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
905 AM EST MON DEC 29 2014
.UPDATE (REST OF TODAY THROUGH TUESDAY)...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THAT MUCH OF THE CONUS IS
NOW UNDER BROAD LONGWAVE TROUGHING...AS THE RIDGE THAT WAS ALONG THE
EASTERN SEABOARD HAS BEEN DEAMPLIFIED BY SHORTWAVE ENERGY PASSING
OFF THE CAROLINA COAST AND PUSHED SOUTHEAST INTO THE WESTERN
ATLANTIC. THE CENTRAL/SOUTHERN FLORIDA PENINSULA IS STILL SOMEWHAT
UNDER THE SUBSIDENCE OF THIS RIDGE...BUT HEIGHTS HAVE CERTAINLY COME
DOWN ACROSS THE PENINSULA DURING THE PAST 24 HOURS. THE MOST
INTERESTING FEATURE IN THE UPPER LEVELS IS A STRONG PIECE OF
SHORTWAVE/JET ENERGY DIVING DOWN THE PACIFIC COAST. THIS ENERGY IS
PROGGED TO EVOLVE INTO A LARGE CUTOFF LOW OVER THE SOUTHWESTERN
STATES BY THE MIDDLE OF THE WEEK AND THEN SLOWLY EJECT EASTWARD
ACROSS THE SOUTHERN PLAINS.
29/12Z KTBW SOUNDING PROFILE SHOWS THAT ALTHOUGH THE RIDGE ALOFT IS
WEAKENING...IT STILL HAS SOME INFLUENCE ON THE REGION. AN ASSOCIATED
SUBSIDENCE INVERSION IS EVIDENT AROUND 850MB WITH QUITE A DRY COLUMN
ABOVE IN THE MID LAYERS OF THE ATMOSPHERE.
AT THE SURFACE...ATLANTIC HIGH PRESSURE RIDGES BACK OVER THE CENTRAL
AND SOUTHERN FL PENINSULA...WHILE AT THE SAME TIME A COLD FRONT
SLOWLY CRAWLS EASTWARD THROUGH THE FL PANHANDLE AND NORTH-CENTRAL
GULF OF MEXICO. THE FLOW BETWEEN THESE 2 FEATURES IS PROVIDING
ABUNDANT LOW LEVEL MOISTURE TO THE REGION. THESE RICH DEWPOINTS
(LOWER 70S AT BUOY 42036) ARE ADVECTING OVER THE LOWER 60S
TEMPERATURE SHELF WATERS OF EASTERN APALACHEE BAY AND RESULTING IN
AREAS OF DENSE SEA FOG. HAVE ISSUED A MARINE DENSE FOG ADVISORY FOR
THE COASTAL WATERS NORTH OF PINELLAS COUNTY. FOR NOW MOST OF THE FOG
IS UP TOWARD THE COASTS OF CITRUS/LEVY COUNTIES...BUT THERE IS A
GOOD CHANCE TO SEE AN EXPANSION OF THIS FOG SOUTHWARD LATER TODAY
AND ESPECIALLY INTO TONIGHT. THIS EXPANSION IS SHOWN BY THE SREF AND
ALSO THE ENSEMBLE LOCAL SUITE OF HIGH RESOLUTION GUIDANCE.
REST OF TODAY...
FOG OVER LAND WILL BURN OFF IN THE NEXT FEW HOURS. ONLY EXCEPTION
MAY BE AT THE IMMEDIATE COASTS OF CITRUS AND LEVY COUNTY AS THE SEA
FOG MOVES ASHORE AND IS NOT INFLUENCED BY DIURNAL MIXING. WILL CALL
IT A "MIX OF SUN AND CLOUDS" IN THE FORECAST AS WE DO HAVE SEVERAL
PATCHES OF CLOUDS AND CLEAR SKIES ACROSS THE REGION. ALL WE NEED IS
A LITTLE BIT OF SUN GIVEN THE THERMAL POTENTIAL OF THE LOW LEVEL
COLUMN TO END UP WITH AN ABOVE NORMAL DAY IN TERMS OF TEMPERATURES.
INLAND LOCATIONS...ESPECIALLY ALONG AND SOUTH OF THE I-4 CORRIDOR
SHOULD REACH THE LOWER 80S...WHILE THINGS HOLD IN THE 70S AT THE
BEACHES DUE TO A DEVELOPING ONSHORE COMPONENT TO THE WIND THIS
AFTERNOON. THE FRONT WILL BE MAKING VERY SLOW PROGRESS EASTWARD
THROUGH THE DAY BUT WILL FAIL TO REACH OUR COUNTIES TODAY. EVEN
STILL...A FEW SHOWERS AHEAD OF THE BOUNDARY MAY REACH LEVY COUNTY
AND THE NORTHERN COASTAL WATERS BY EARLY THIS EVENING. JUST HAVE A
20% CHANCE OF A SHOWER THROUGH THE EVENING FOR LEVY COUNTY AS THE
OVERALL SYNOPTIC SETUP FOR LIFT ALONG THE BOUNDARY WILL BE FADING
WITH TIME. CAN NOT RULE OUT A BRIEF SHOWER OR 2 DEVELOPING OVER THE
INTERIOR SOUTH-CENTRAL ZONES EITHER AS A RESULT OF A LATE DAY
SEA-BREEZE MERGER. A FEW OF THE LOCAL CONVECTION ALLOWING MODELS ARE
SHOWING THIS POTENTIAL AND WILL KEEP THE 20% POP AFTER 18Z OVER
HIGHLANDS COUNTY.
TONIGHT...
THE APPROACH OF ONE FINAL PIECE OF WEAK SHORTWAVE ENERGY OVER THE
NORTHERN GULF COAST WILL FINALLY GIVE THE FRONT THE PUSH IT NEEDS TO
ENTER THE FL PENINSULA. THE BOUNDARY SHOULD BE LOCATED SOMEWHERE
BETWEEN TAMPA AND CHIEFLAND BY SUNRISE ON TUESDAY. WILL HAVE TO PUT
A FEW SHOWERS IN THE FORECAST FROM TAMPA NORTHWARD IN PROXIMITY TO
THIS BOUNDARY...HOWEVER ANY RAINFALL DOES NOT LOOK TO BE A BIG
DEAL...WITH VERY LOW QPF. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH
LOWS IN THE 60S FOR ALL.
TUESDAY...
COLD FRONT MAKES SLOW BUT STEADY PROGRESS SOUTHWARD THROUGH THE DAY
REACHING THE SOUTHERN FL PENINSULA TUESDAY EVENING. A FEW SHOWERS
WILL REMAIN IN THE FORECAST...ALTHOUGH THE BEST CHANCES WILL SLIP TO
THE SOUTHERN HALF OF THE REGION BY THE AFTERNOON. DO NOT ANTICIPATE
THAT TUESDAY WILL BE CONSIDERED A "WET" DAY. ONCE AGAIN...ANY
SHOWERS SHOULD BE BRIEF AND QPF IS QUITE LOW. THERE REALLY IS NOT A
WHOLE LOT OF COLD AIR BEHIND THIS COLD FRONT. WE WILL SEE SOME
DECREASE IN TEMPS INTO THE MIDDLE OF THE WEEK...BUT MAINLY IT WILL
GET DRIER AND MORE COMFORTABLE FEELING. HOWEVER...DO NOT GET USED TO
IT...AS ALL SIGNS POINT TO A QUICK MODERATING TREND IN BOTH
TEMPERATURES AND DEWPOINTS AS HEAD TOWARD THE END OF THE WEEK.
&&
.AVIATION...
CONDITIONS HAVE RETURNED TO VFR FOR ALL TERMINALS THIS MORNING.
AREAS OF BKN CLOUDS 3500-4500 FEET WILL BE AROUND...BUT DO NOT
ANTICIPATE ANY ADDITIONAL RESTRICTIONS ALONG OR SOUTH OF THE I-4
CORRIDOR THE REMAINDER OF THE DAY AND EVENING HOURS. AFTER MIDNIGHT
INTO EARLY TUESDAY MORNING IS LOOKING MORE AND MORE FAVORABLE FOR
PERIOD OF SIGNIFICANT RESTRICTIONS AT ALL TERMINALS. THE STATISTICAL
AND DETERMINISTIC GUIDANCE SOLUTIONS ARE ALL POINTING TO WIDESPREAD
DENSE FOG AND LOW CEILINGS. WILL CONTINUE TO MONITOR THE INCOMING
GUIDANCE AND BEGIN TO MAKE ADJUSTMENTS WITH THE 18Z TAF PACKAGE.
&&
.MARINE...
DENSE FOG ADVISORY REMAINS IN EFFECT FOR THE NORTHERN COASTAL WATERS
AS WARM...HUMID AIR CONTINUES TO OVERRIDE THE COOLER WATERS. PATCHY
FOG WILL BE POSSIBLE ACROSS THE REST OF THE WATERS TODAY BUT BEST
CHANCES APPEAR TO BE NORTH OF PINELLAS COUNTY.
OTHERWISE...A WEAK FRONTAL BOUNDARY WILL APPROACH THE AREA LATE
TONIGHT AND INTO TUESDAY WITH A SLIGHT CHANCE OF SHOWERS POSSIBLE.
THE WINDS WILL SHIFT TO THE NORTH AND NORTHEAST IN THE WAKE OF THIS
FRONT ON TUESDAY...AND WILL REMAIN OUT OF THE NORTHEAST THROUGH THE
REMAINDER OF THE UPCOMING WEEK AS HIGH PRESSURE SETTLES INTO THE
REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 67 77 61 / 10 10 30 10
FMY 82 66 81 65 / 10 10 20 10
GIF 81 65 79 61 / 10 10 30 10
SRQ 79 65 77 62 / 10 10 30 10
BKV 80 63 78 55 / 10 20 30 10
SPG 77 66 76 62 / 10 10 30 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...DENSE FOG ADVISORY UNTIL 1 AM EST TUESDAY FOR TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE/AVIATION...MROCZKA
MARINE...MCKAUGHAN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
532 AM CST MON DEC 29 2014
.SHORT TERM...
220 AM CST
THROUGH TUESDAY...
PRIMARY FORECAST CHALLENGE IN THE SHORT TERM IS WITH LAKE EFFECT
POTENTIAL THROUGH TONIGHT. DESPITE MODERATELY COLD AIR MASS IN PLACE
LAKE EFFECT THUS FAR TONIGHT HAS BEEN ABSENT AND THERMODYNAMICS ARE
NOT EXPECTED TO IMPROVE THIS MORNING SO PLAN TO JUST HOLD ON TO
SLIGHT CHANCE OF SNOW SHOWERS AND CHANCE OF FLURRIES ALONG THE
ILLINOIS LAKE SHORE THIS MORNING. BEST HOPE OF LAKE EFFECT SNOW
SHOWERS/FLURRIES THIS MORNING WILL HINGE ON MID LEVEL CLOUDINESS
BEGINNING TO SPREAD IN ACTUALLY SEEDING THE LAKE STRATOCUMULUS.
LOW LEVEL FLOW WILL GRADUALLY BACK TO NORTH THIS AFTERNOON THEN
NORTH-NORTHWEST WITH THE RESULTANT LAKE EFFECT POTENTIAL PIVOTING
AROUND THE SOUTH RIM OF LAKE MICHIGAN THROUGH TONIGHT.
THERMODYNAMICS COULD IMPROVE SLIGHTLY THIS AFTERNOON...THOUGH
GETTING INTO A DIURNALLY UNFAVORABLE TIME OF DAY CONSIDERING THE
STILL MARGINAL SET UP FOR LAKE EFFECT SNOW TO GET CRANKING THIS
AFTERNOON. PLAN TO JUST GRADUALLY SHIFT FLURRIES/SMALL SNOW SHOWERS
CHANCES EAST FOCUSING MORE INTO NW INDY AND EXTREME SE COOK THIS
AFTERNOON.
MORE FAVORABLE THERMODYNAMIC ENVIRONMENT WILL DEVELOP THIS EVENING
AND CONTINUE OVERNIGHT WITH IMPROVED INSTABILITY AND SLIGHTLY HIGHER
INVERSION HEIGHTS. WILL MAINTAIN HIGH CHANCE/LOW END LIKELY POPS
NEAR THE LAKE TONIGHT BUT ACCUMULATIONS WILL PROBABLY BE PRETTY
MINOR BECAUSE AS THERMAL INSTABILITY INCREASES...MODELS ALSO PROG
INCREASINGLY DRY AIR TO SPREAD IN JUST ABOVE THE BOUNDARY LAYER
INVERSION WHICH GIVEN THE MARGINAL TEMPS IN THE CLOUD BARING LAYER
REALLY DOES NOT BODE WELL FOR EFFICIENTLY ACCUMULATING SNOW. CURRENT
THINKING IS NO ACCUMULATION IN NE IL AND MOSTLY LESS THAN AN INCH IN
NW INDY TONIGHT...THOUGH ISOLATED AMOUNTS OF 1 TO POSSIBLY UP TO 2
INCHES WOULD BE ON THE HIGH SIDE. LAKE EFFECT THREAT WILL SHIFT EAST
OUT OF THE CWA TUESDAY AND SHOULD SEE CLOUDS CLEAR OUT AND SKIES
BECOME SUNNY...BUT THE SUNSHINE WILL BE MORE FOR SHOW THAN ANYTHING
ELSE AS TEMPS STRUGGLE TO REACH 20F.
IZZI
&&
.LONG TERM...
220 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
COLD AIR MASS WILL REMAIN ENTRENCHED WEDNESDAY BUT MAGNITUDE OF THE
COLD WILL NO DOUBT BE TEMPERED BY THE LACK OF SNOW COVER HERE OR
EVEN FAR UPSTREAM...SO WHILE IT WILL BE COLD HAVE GONE WITH TEMPS A
BIT ABOVE WHAT 850MB/925MB CLIMO WOULD SUPPORT. WARM ADVECTION
BEGINS WEDNESDAY NIGHT AND REALLY CRANKS INTO GEAR THURSDAY ALLOWING
FOR A NICE REBOUND IN TEMPS...THOUGH THE WARMING WILL BE MORE
ACADEMIC THAN ACTUALLY FELT AS GUSTY SOUTHWEST WINDS PRODUCE STILL
CHILLY WIND CHILLS THURSDAY. TEMPS SHOULD CONTINUE TO MODERATE ON
FRIDAY WITH PRECIPITATION LOOKING PRETTY UNLIKELY FRIDAY.
STRONG TROUGH WILL TO DIG INTO THE DESERT SOUTHWEST NEW YEARS EVE
AND IS FORECAST TO PRODUCE ACCUMULATING SNOW ON THE LAS VEGAS STRIP
NEW YEARS EVE WHERE WINTER STORM WATCHES ARE IN EFFECT! THIS
POWERFUL SYSTEM IS PROGGED TO CLOSE OFF A LARGE DEEP CIRCULATION
THAT BECOMES CUT OFF FROM THE WESTERLIES. A SET UP LIKE THIS MORE
OFTEN THAN NOT SPELLS BIG TROUBLES FOR PREDICTABILITY IN THE MEDIUM
RANGE AS THIS SYSTEM WILL PRESENT A COUPLE OF THE THINGS THAT MODELS
STRUGGLE WITH...FIRST HANDLING TRACK/TIMING OF EJECTING SOUTHWEST
CUT OFFS AND SECOND THE POTENTIAL FOR PHASING WITH NORTHERN STREAM
SHORTWAVE ENERGY.
THE RANGE OF POSSIBILITIES FOR THE WEEKEND IN OUR AREA TRULY RUN THE
GAMUT FROM DRY CONDITIONS ALL WEEKEND TO RAIN...ACCUMULATING
SNOW...A WINTRY MIX...OR SOME COMBINATION OF THE ABOVE. THE
OPERATIONAL GFS IS MOST GUNG-HO WITH PHASING AND FASTEST EJECTING
THE LOW EASTWARD...WHICH WOULD SEEM TO COUNTER WHAT IS TYPICAL IN
THESE SCENARIOS. THE PARALLEL GFS AND ECMWF ARE BOTH SOUTH AND
SLOWER WITH THE SYSTEM AND WOULD LEAD TO A DRY WEEKEND IN OUR AREA.
THE BLENDED MODEL POPS FOR THE WEEKEND HAVE COME DOWN FROM PREVIOUS
CYCLES AND AM NOT PLANNING ANY CHANGES TO THEM AS PREDICTABILITY IS
JUST TOO LOW AT THIS POINT. AT THIS POINT THE CHANCES OF THE LAS
VEGAS STRIP SEEING MORE ACCUMULATING SNOW THE NEXT 7 DAYS IS
CURRENTLY HIGHER THAN HERE IN OUR CWA...QUITE ATYPICAL AND
DEFINITELY NOT SOMETHING THAT ONE WOULD TYPICALLY WAGER WOULD BE
THE CASE!
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* SOME MVFR/LOW END VFR CIGS DEVELOPING AFTER DAYBREAK...AND
CONTINUING AT TIMES MONDAY.
* LAKE EFFECT FLURRIES THIS MORNING...AND POSSIBLY AGAIN BRIEFLY
THIS EVENING.
* NORTH/NORTHEAST WINDS APPROACHING 10KT THIS AFTERNOON.
KMD
//DISCUSSION...UPDATED 12Z...
LOW CLOUDS OVER SE WI ARE GONE...AND NOW WAITING FOR THE LAKE
STRATOCUMULUS. DIFFICULT TO SEE WHERE THE LOW CLOUDS ARE GIVEN THE
MID AND HIGHER CLOUD COMING IN ABOVE IT..BUT MVFR OR VERY LOW VFR
HAS LARGELY FILLED IN ON THE EAST SIDE OF LAKE MICHIGAN BASED ON
SURFACE OBS..AND KUGN IS SEEING THE LOW CLOUDS TOO...BUT VERY
LITTLE DOWNTOWN BASED ON SPOTTER REPORTS EARLY THIS MORNING. WINDS HAVE
TURNED NORTHERLY AND ARE EXPECTED TO TURN NORTHEASTERLY THIS
MORNING. THIS SHOULD ALLOW HIGH END MVFR OR LOW END VFR CIGS TO
ROLL IN CLOSER TO THE LAKE...THOUGH WITH LOW CONFIDENCE OF HOW FAR
INLAND THEY WILL GO. ALSO NOT SEEING MUCH IN THE WAY OF
FLURRIES/SNOW SHOWERS...THOUGH RAP/HRRR STILL ATTEMPT TO BRING A
FEW OVER THE NEAR LAKE AREAS. MODELS SUGGEST THAT ANY MVFR TO FORM
MAY NOT REMAIN FILLED IN. A SECONDARY SURGE OF LAKE CLOUDS COULD
VERY WELL SLIDE EAST OF ALL BUT GYY. WINDS TODAY WILL LIKELY
REMAIN NE AROUND 10 KT...POSSIBLY SOONER THAN IN THE CURRENT TAF.
WINDS THEN BACK TO NW IN THE EVENING.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM-HIGH FOR MVFR CIGS...MEDIUM FOR TIMING AND HOW LONG THEY LAST.
* LOW-MEDIUM FOR LAKE EFFECT FLURRIES MONDAY/MONDAY EVENING.
* MEDIUM FOR WINDS THRU THE PERIOD.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
247 AM CST
A COLD FRONT WILL CLEAR THE SOUTH END OF THE LAKE LATER THIS MORNING
AS STRONG HIGH PRESSURE IN NORTHWEST CANADA BEGINS TO BUILD SOUTH
INTO THE CENTRAL PLAINS. AS THE HIGH CONTINUES TO SLIDE INTO THE
PLAINS...LOW PRESSURE WILL TRACK SOUTHEAST THROUGH HUDSON BAY.
EXPECT A DECENT GRADIENT TO SETUP BETWEEN THESE TWO STRONG FEATURES.
THIS WILL CREATE A PERIOD OF GALES OVER THE LAKE WEDNESDAY AND
WEDNESDAY EVENING. THE HIGH WILL THEN SHIFT INTO THE TENNESSEE
VALLEY AND WEAKEN WHILE THE HUDSON BAY LOW RETREATS INTO THE
CANADIAN MARTIMES ON FRIDAY.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
308 AM CST Mon Dec 29 2014
.SHORT TERM...(Today)
ISSUED AT 308 AM CST MON DEC 29 2014
08z/2am surface analysis shows strong 1057mb high over northern
British Columbia/Alberta. Bitterly cold airmass beneath the high
with current temps in the teens and 20s below zero is building
southward into the Northern Plains/Upper Midwest, with the leading
edge of the colder air sinking toward northern Illinois. Front will
remain north of the KILX CWA today: however, increasing mid/high
clouds in the vicinity of the boundary will be noted across the
north. End result will be partly to mostly cloudy skies north of
Peoria, with mostly sunny skies further south across the remainder
of the area. High temperatures will once again be near normal for
this time of year in the middle to upper 30s.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 308 AM CST MON DEC 29 2014
Main weather story this week will be the shot of very cold air
expected Tuesday through Thursday. Arctic cold front will settle
southward into central Illinois tonight, accompanied by clouds and
perhaps a few flurries. NAM time-height cross-sections show much
shallower moisture profiles and weaker lift than they did on
previous runs: however, think strong CAA will still be enough to
produce scattered flurries overnight. Any flurries will come to
an end Tuesday morning as high pressure builds into the region and
skies gradually clear. High temperatures will be much colder than
today, ranging from the lower 20s northwest to the lower 30s south
of I-70. Heart of the coldest airmass will arrive Tuesday night
into Wednesday. Thanks to clear skies and diminishing winds, low
temperatures Tuesday night will bottom out in the single digits
and teens, with corresponding wind-chill readings dropping below
zero. Despite full sunshine, highs on Wednesday will struggle to
reach the lower to middle 20s. As high pressure sinks south of
the region, winds will back to the southwest and help boost temps
back into the lower 30s by Thursday.
Forecast becomes more complicated later in the week, as a southern
stream system slowly approaches from the southwest. Model-to-model
as well as run-to-run consistency remains poor, so forecast
confidence beyond Thursday is low. Latest trend observed with the
00z Dec 29 model suite suggests a deeper cut-off low over the Desert
Southwest and thus a slower northeastward ejection. Current water
vapor imagery shows a strong jet streak diving southward along the
West Coast, which is progged to carve out a closed upper low over
California within the next 48 hours. Models are in very good
agreement initially, showing the low meandering slowly eastward to
the Texas/Oklahoma panhandles by Saturday evening: however, they
have very different ideas on how to handle precip ahead of the
system. The ECMWF shows precip breaking out well in advance of
the low across the southern Plains Thursday, then spreading
northeastward into south-central Illinois and the Ohio River
Valley late Thursday night into Friday. Given presence of
cold/dry airmass across the region, am very skeptical about this
aggressive push of precip. As a result, will continue with a dry
forecast Thursday night and will reduce PoPs significantly during
the day Friday. The GFS seems to have a much more realistic
solution, showing precip remaining south of Illinois until Friday
night into Saturday. Models are in poor agreement with what
happens to the southwest system over the weekend, with the ECMWF
maintaining a closed 500mb low longer than the GFS, which opens
the wave and allows it to be absorbed into the northern stream
much faster. If the ECMWF verifies, much of the precip associated
with the low will remain southeast of Illinois across the Ohio
River Valley. This is a drastic change from its previous runs, so
am looking at this with a great deal of skepticism. Prefer the
more consistent GFS, which opens the low and brings it northward
into the area on Saturday. As a result, have introduced chance
PoPs across the board Friday night/Saturday, then have ended
precip chances by Sunday as the system exits into the Great Lakes.
Precip type will be an issue as well, with forecast soundings and
surface temps initially supporting snow or a rain/snow mix.
Atmosphere will likely warm enough to change the precip to mostly
rain on Saturday before colder air returns Saturday night into
Sunday. Overall this does not look like a major winter storm for
central Illinois, but future model runs will need to be monitored
for any potential changes.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1146 PM CST SUN DEC 28 2014
High pressure centered across our counties will keep VFR
conditions in general. Some fog is indicated in the HRRR and RAP
models along the ridge axis for CMI and DEC. The RAP goes all the
way to VLIFR with the fog across CMI/DEC/SPI, while the HRRR keeps
the LIFR fog east of CMI. Will add MVFR fog at CMI and DEC as
light fog is developing along that axis already near-by.
A weak cold front extending from SE Nebraska to southern Michigan
will slowly drift to the southeast over the next day. As the cold
front approaches Monday evening, MVFR clouds are expected to
arrive from NW to SE.
The increasing clouds will be triggered by a shortwave moving
east along the front as it arrives in the area. A few flurries
could develop for the northern terminals of PIA and BMI. Models
have trended drier with the last 2 runs, so do not expect any snow
accumulation as the NAM was suggesting previously. Will add -sn at
PIA and BMI Monday evening, and keep the other TAF sites dry.
Winds will remain calm under the surface ridge axis tonight. A
northeast wind will develop by mid-morning on Monday and continue
through the rest of the TAF period. Wind speeds will remain less
than 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS JACKSON KY
1041 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 1041 AM EST MON DEC 29 2014
A MOIST LOWER PORTION OF THE ATMOSPHERE COUPLED WITH A SLOWLY EXITING
LOW PRESSURE SYSTEM ON THE LEE SIDE OF THE APPALACHIANS HAS AND WILL
RESULT IN LINGERING CLOUD COVER OVER EASTERN KENTUCKY. IN FACT...WEAK
N TO NNE FLOW INTO THE AREA IS BARELY ERODING ANY CLOUD COVER OVER IN
CENTRAL OH AND IN. WILL EXPECT CLOUD COVER TO LINGER THROUGH TODAY
AND INTO TONIGHT...AT LEAST INTO EASTERN KENTUCKY. THE NORTHERN AND
WESTERN BLUEGRASS AREAS WILL EVENTUALLY BEGIN TO CLEAR OUT
TONIGHT...EVEN INTO FLEMING...BATH AND ROWAN COUNTIES. WITH THIS IN
MIND...HAVE UPDATED THE FORECAST TO LOWER MAX TEMPS FOR TODAY AS
CLOUD COVER WILL KEEP ANY HEATING FROM REACHING THE
SURFACE...ESPECIALLY IN A NORTHERLY FLOW. SOME LINGERING DRIZZLE AND
LIGHT RAIN STILL REMAIN IN THE EAST THIS MORNING AND MAY LINGER INTO
THE AFTERNOON BANKED AGAINST THE HIGHER TERRAIN IN THE EAST. STILL
ONLY A SLIGHT CHANCE IS WORTH MENTIONING. THE FOG WAS LEFT IN THE
FORECAST AS SOME OBSERVATIONS WERE STILL SHOWING SOME GROUND TRUTH OF
THIS. THE FOG MAY LINGER THROUGHOUT THE ENTIRE DAY WITH THE MOIST
BOUNDARY LAYER AND DRIZZLE PRESENT. WILL VISIT THIS AGAIN AROUND THE
NOON TIME PERIOD. A NEW ZFP HAS BEEN SENT OUT TO ADDRESS THESE
CHANGES.
UPDATE ISSUED AT 640 AM EST MON DEC 29 2014
WSR-88D RADAR CONTINUES TO INDICATE SOME LIGHT RAIN AND DRIZZLE THIS
MORNING WITH BEST RETURNS ACROSS THE FAR SE PORTIONS OF THE CWA. ALSO
WITH LOW LEVEL MOISTURE IN PLACE THERE WILL BE PATCHY FOG IN SPOTS
WITH MANY METAR SITES COMING IN WITH ANYWHERE FROM HALF A MILE TO TWO
AND A HALF MILE VIS THIS MORNING. SO DID UPDATE WITH SOME DRIZZLE AND
PATCHY FOG. ALSO FRESHENED UP TEMPS/DEWPOINTS/WIND WITH LATEST OBS
AND TRENDS. NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 647 AM EST MON DEC 29 2014
DRIZZLE AND LIGHT RAIN HAS BEEN THE TREND OVERNIGHT. TAF SITES HAVE BEEN
FLUCTUATING OVERNIGHT SOME WITH MOST SITES STAYING IFR TO LIFR CONDITIONS.
SOME DRIER AIR HAS BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE
CWA WITH SYM CIGS MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE
AT MOST SITES AND COULD BRING LOWER CONDITIONS TO THESE SITES THAT
SEE THE HIGHER CIGS. MOVING INTO TODAY WOULD EXPECT SOME
IMPROVEMENTS TO THE TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES
ARE ONLY EXPECTED TO IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO THIS
AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
648 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 640 AM EST MON DEC 29 2014
WSR-88D RADAR CONTINUES TO INDICATE SOME LIGHT RAIN AND DRIZZLE THIS
MORNING WITH BEST RETURNS ACROSS THE FAR SE PORTIONS OF THE CWA. ALSO
WITH LOW LEVEL MOISTURE IN PLACE THERE WILL BE PATCHY FOG IN SPOTS
WITH MANY METAR SITES COMING IN WITH ANYWHERE FROM HALF A MILE TO TWO
AND A HALF MILE VIS THIS MORNING. SO DID UPDATE WITH SOME DRIZZLE AND
PATCHY FOG. ALSO FRESHENED UP TEMPS/DEWPOINTS/WIND WITH LATEST OBS
AND TRENDS. NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 647 AM EST MON DEC 29 2014
DRIZZLE AND LIGHT RAIN HAS BEEN THE TREND OVERNIGHT. TAF SITES HAVE BEEN
FLUCTUATING OVERNIGHT SOME WITH MOST SITES STAYING IFR TO LIFR CONDITIONS.
SOME DRIER AIR HAS BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE
CWA WITH SYM CIGS MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE
AT MOST SITES AND COULD BRING LOWER CONDITIONS TO THESE SITES THAT
SEE THE HIGHER CIGS. MOVING INTO TODAY WOULD EXPECT SOME
IMPROVEMENTS TO THE TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES
ARE ONLY EXPECTED TO IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO THIS
AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
716 AM CST MON DEC 29 2014
...SOUNDING DISCUSSION...
IN RESPONSE TO THE COLD FRONTAL PASSAGE...THE LOW LEVELS HAVE
COOLED OFF SINCE YESTERDAY MORNING. A STABLE PROFILE IS FOUND
WITH POSITIVE LIFTED INDEX AND NO MLCAPE. WINDS ARE LIGHT AND
VARIABLE IN THE LOW LEVELS AND WITH THE LOWEST 1000 FEET OR SO
REMAINING SATURATED ADVECTION FOG HAS FORMED. SOME CLOUDS
ASSOCIATED WITH THE DEPARTING COLD FRONT ARE VISIBLE ON IR
IMAGERY AND ARE LIKELY AROUND 11000 FEET PER NEARLY SATURATED
LAYER AT THAT LEVEL. WINDS BETWEEN 5000 AND 8000 FEET WERE FROM
THE WEST AND ABOVE 8000 FEET WERE MAINLY FROM THE SOUTHWEST. A
PEAK WIND SPEED OF 115 KNOTS WAS LOCATED AT 39500 FEET.
12Z BALLOON INFO: NO ISSUES WITH THE 119 MINUTE FLIGHT THIS MORNING.
THE BALLOON REACHED A HEIGHT OF 21.9 MILES ABOVE THE GROUND BEFORE
BURSTING NEAR AXIS AL 114 MILES DOWNRANGE FROM THE OFFICE.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 348 AM CST MON DEC 29 2014/
SHORT TERM...
COLD FRONT HAS FINALLY PUSHED OFFSHORE AND IS SLOWLY PROGRESSING
EASTWARD. A BAND OF LIGHT TO MODERATE RAN HAS DEVELOPED ACROSS
PLAQUEMINES PARISH...EXTENDING NORTHEASTWARD TOWARDS THE ALABAMA
COAST. THE HRRR SHOWS THIS ACTIVITY HANGING AROUND FOR A COUPLE MORE
HOURS BEFORE SHIFTING OFFSHORE. THIS COINCIDES WELL WITH LATEST
WATER VAPOR IMAGERY WHICH INDICATES THAT DRIER MID LEVEL AIR SHOULD
BE ARRIVING AT ABOUT THAT SAME TIME. ISOLATED SHOWERS COULD LINGER
FOR A FEW HOURS IN THE MORNING ALONG COASTAL AREAS. OTHERWISE...IT
DOES APPEAR LOW LOW LEVEL STRATUS DECK WILL HANG AROUND ALL DAY AND
TONIGHT AS WELL. HAVE MADE ADJUSTMENTS TO THE ZONES FOR THAT. IN
ADDITION...HAVE KEPT HIGHS A COUPLE DEGREES COOLER THAN MAV GUIDANCE
TO ACCOUNT FOR LESS THAN EXPECTED INSOLATION.
AN UPPER LEVEL TROUGH DROPPING OUT OF CANADA EARLY THIS WEEK WILL
SEND A SECONDARY SURGE OF COLDER AIR TO THE AREA TUESDAY. STRONG
COLD AIR ADVECTION WILL PERSIST FOR AT LEAST A COUPLE DAYS. THIS
WILL DROP TEMPERATURES TO ABOUT 10 DEGREES BELOW NORMAL WED AND
THURS. COULD SEE FREEZE TEMPS FOR LOWS THURSDAY MORNING.
LONG TERM...
MODELS STILL SHOWING AN UPPER LEVEL LOW CLOSING OFF OVER THE DESERT
SOUTHWEST MID WEEK AND TRACKING EASTWARD ACROSS THE CENTRAL PLAINS
THIS WEEKEND. SHOWERS AND THUNDERSTORMS ARE EXPECTED LOCALLY AHEAD
OF THIS FEATURE AS MOISTURE INCREASES ACROSS THE AREA. HAVE BUMPED
UP POPS TO 60 PERCENT ON FRIDAY AND 60-70 PCT FOR SATURDAY.
INSTABILITY LOOKS TO BE DEVELOPING SATURDAY AS LOW LEVELS WARM AND
MID/UPPER LEVEL COOLING TAKES PLACE. A FEW MARGINALLY STRONG TO
SEVERE STORMS COULD DEVELOP BUT THATS STILL SEVERAL DAYS OUT AT THIS
TIME TO KNOW WITH ANY DEGREE OF CERTAINTY. UPPER/SFC LOW PLACEMENT
AMONG OTHER THINGS COULD CHANGE QUITE A BIT BETWEEN NOW AND THEN.
JUST WANTED TO MENTION THE POSSIBILITY.
MEFFER
AVIATION...
A LOW STRATUS DECK WILL REMAIN OVER THE TERMINALS THROUGH THE ENTIRE
FORECAST PERIOD. CEILINGS WILL GENERALLY RANGE FROM 300 TO 800
FEET..RESULTING IN LIFR AND IFR CONDITIONS AT ALL OF THE TERMINALS
THROUGH AROUND 15Z. AFTER 15Z...CONDITIONS SHOULD IMPROVE
SLIGHTLY...WITH CEILINGS GENERALLY RANGING FROM 1000 TO 1500 FEET.
THESE MVFR CONDITIONS WILL PERSIST THROUGH 00Z. HOWEVER...STRATUS
BUILD DOWN WILL OCCUR AFTER 00Z...AS AN ELEVATED INVERSION
STRENGTHENS. A RETURN TO IFR AND LIFR CEILINGS RANGING FROM 300 TO
800 FEET IS EXPECTED BY 03Z. 32
MARINE...
NORTHEAST FLOW OF 10 TO 15 KNOTS WILL RISE INTO SMALL CRAFT EXERCISE
CAUTION RANGE LATE TONIGHT AND TOMORROW AS A COOLER AND DRIER
AIRMASS ADVECTS OVER THE COASTAL WATERS. THIS STRONGER NORTHEAST
FLOW OF 15 TO 20 KNOTS WILL PERSIST THROUGH WEDNESDAY NIGHT. WINDS
WILL VEER TO AN EASTERLY DIRECTION AS THE HIGH SHIFTS TO THE
EAST...AND ANOTHER AREA OF LOW PRESSURE BEGINS TO FORM IN THE
WESTERN GULF OF MEXICO. AS THE LOW SLOWLY MOVES NORTH INTO EASTERN
TEXAS AND WESTERN LOUISIANA FRIDAY AND SATURDAY...WINDS WILL FURTHER
VEER TO THE SOUTHEAST AND REMAIN IN EXERCISE CAUTION RANGE. SEAS
WILL INCREASE TO 4 TO 6 FEET IN THE OUTER WATERS DURING THIS PERIOD. 32
DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
FLOOD WATCH
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 54 42 55 33 / 10 10 0 0
BTR 57 44 58 36 / 10 10 0 0
ASD 61 46 60 35 / 10 0 0 0
MSY 60 49 59 42 / 10 0 0 0
GPT 63 47 60 38 / 10 0 0 0
PQL 63 47 61 35 / 10 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
549 AM EST MON DEC 29 2014
.SYNOPSIS...
WEAK DISTURBANCES WILL RIDE ALONG A COLD FRONT...MAINLY TO OUR
SOUTH...TODAY THROUGH TUESDAY. HIGH PRESSURE WILL BUILD INTO THE EASTERN
HALF OF THE COUNTRY FOR THE SECOND HALF OF THE WEEK. LOW PRESSURE
IS EXPECTED TO AFFECT THE MID ATLANTIC REGION THIS WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
QUICK UPDATE ON PRECIP TONIGHT INTO TUESDAY...
AS OF 08Z...1055MB SFC HIGH IS NORTH OF CALGARY WHILE AN UPR LOW IS
OVER NRN QUEBEC AND AN UPR TROUGH IS OVER THE INTERMOUNTAIN WEST. A
WEAK COLD FRONT EXTENDS FROM A LOW EAST OF NEWFOUNDLAND TO THE
CAROLINAS. HIGH PRESSURE WILL BUILD NORTH OF THE CWA TODAY...WITH A
NELY FLOW OF 10 MPH OR SO SETTING UP. RAIN CURRENTLY ALONG SOUTHERN
PERIPHERY OF CWA (WITH PATCHY SPRINKLES/LIGHT RAIN UP THROUGH THE DC
METRO AREA) WILL CONTINUE TO DRIFT SOUTH THROUGH TODAY. REDUCED POPS
ACROSS THE BALT-WASH METRO PER RECENT HRRR RUNS AND OBSERVED RADAR
TRENDS. RAIN WILL CONTINUE TO BE LIGHT WITH LESS THAN A TENTH INCH
QPF. MAX TEMPS LOW TO MID 40S UNDER PERSISTENT MID-LEVEL CLOUDS.
ELY COMPONENT WILL PROMOTE PRECIP DEVELOPMENT FOR CNTRL VA BLUE
RIDGE AND AREAS FARTHER WEST. COLDER AIR THERE WILL ALLOW SOME SNOW
ABOVE ABOUT 2500 FT TODAY...LOWERING BELOW 1000 FT TONIGHT.
EXPANDED CHANCE POPS FARTHER NORTHEAST TOWARD THE BALT-WASH METRO
AREA PER 06Z NAM/GFS. LOOKS LIKE SOME AGEOSTROPHIC FORCING ALONG
A BAROCLINIC ZONE WILL AID FORCING IN SPITE OF MSLP APPROACHING
1030MB. . ADDED SOME LIGHT SNOW AMOUNTS ACROSS THE N-CNTRL VA
PIEDMONT. SNOW PROBS UPDATED AS WELL WHICH HIGHLIGHTS THE THREAT
FOR BANDED SNOW WHICH COULD ACCUMULATE ONE TO TWO INCHES FAIRLY
QUICKLY...SHOULD THEY SET UP. CLOUDY ACROSS THE CWA WITH MIN
TEMPS UPR 20S TO LOW 30S (MID 30S FOR NEAR SHORE).
PRECIP SHIFTS SOUTH TUESDAY AS HIGH PRESSURE CONTINUES TO MOVE
INTO THE CWA FROM THE WEST. EXPECT LIGHT NLY FLOW AND MAX TEMPS
UPR 30S TO LOW 40S UNDER CLEARING SKIES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
HIGH PRES XPCTD TO BUILD INTO THE AREA FOR NEW YRS EVE...SO WX WL
NOT BE A PROBLEM WED NGT OR THE 1ST DAY OF 2015. THE HIGH SHOULD
RMN IN CONTROL OF MID ATLC WX THRU THE END OF THE WK. THIS WL
ALLOW TEMPS TO MODERATE - THU MRNG LOWS WL MAINLY BE IN THE
L20S...BY SAT MRNG ABT TEN DEGS WARMER. THE SAME WL BE TRUE W/
HIGH TEMPS - THU ARND 40...A50 SAT.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LOW PRES WL BE INFLUENCING THE ERN U.S. OVR THE WKND. THERE IS
DIFFERENCE IN THE MDLS AS TO THE TRAJECTORY OF THE SYSTEM - EURO
HAS IT ON A SRN TRACK WHILE THE GFS TAKES IT INTO THE ERN GRT LKS
ALNG W/ A COLD FNT PUSHING ONTO THE E CST. OBVIOUSLY THIS WL NEED
TO RESOLVED IN THE COMING DAYS. AT THIS MOMENT P-TYPE LOOKS TO BE
LIQUID. IF TEMPS ARE ABLE TO DROP BLO FRZG THEN FZRA WL NEED TO BE
CONSIDERED BUT THAT IS A LONG WAY AWAY.
LOOKING AT THE HEMISPHERIC 500 MB PATTERN OF BOTH THE GFS AND
ECM...THE COLDEST AIR LOOKS TO RMN LOCKED OVR HUDSON BAY INTO NEXT
WK. JAN 5-8 2014 SAW XTRMLY COLD AIR IN THE CWA AND THE ISSUANCE OF
MULTIPLE WIND CHILL ADVISORIES AND WRNGS (ACTUAL WIND CHILL OF -11
AT DCA....BLO -40 IN THE HIGHLANDS). NO REPEAT IN 2015.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR CONDS CONTINUE TO PREVAIL AS COLD FRONT AND ASSOCIATED RAIN
CONTINUES TO MOVE SOUTH.
VFR CONDS XPCTD TUE NGT THRU FRI.
&&
.MARINE...
LIGHT SWLY FLOW VEERS NWLY TODAY AS A COLD FRONT CROSSES THE WATERS
THIS AFTERNOON AND EVENING. COULD BE A NLY SURGE WITH GUSTS AROUND
18 KT LATE TONIGHT. DID NOT RAISE AN SCA DUE TO UNCERTAINTY...BUT
ONE OUT OF SANDY POINT IS POSSIBLE INTO MONDAY.
NO PROBS XPCTD TUE NGT THRU FRI ON THE WATERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
710 AM EST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST MON DEC 29 2014
TODAY AND TONIGHT WILL BE MARKED BY PERSISTENT COOL NW FLOW...WITH
DAYTIME HIGHS FALLING ANOTHER 5F FROM WHAT WAS REALIZED SUNDAY. A
WEAK SFC TROUGH SET UP ACROSS THE CWA WILL CONTINUE TO BE ERODED FOR
ALL BUT FAR E UPPER MI/LAKE SUPERIOR AS VERY STRONG 1060-1062MB
ARCTIC HIGH PRESSURE OVER CENTRAL BRITISH COLUMBIA AND ALBERTA THIS
MORNING.
EXPECT TO SEE SOME TEMPORARY IMPROVING CONDITIONS LES WISE FROM
DAYBREAK THROUGH THE EARLY AFTERNOON HOURS AS THE INITIAL SHORTWAVE
SHIFTS A BIT FARTHER TO OUR N. A SECODARY TROUGH/SHORTWAVE IS
BRINGING HIGH CLOUDS TO THE S TIP OF THE CWA THIS MORNING.
PERSISTENT OFF AND ON LES WILL CONTINUE OUR HIGH POP/LOW QPF
SCENARIO...WITH ONLY A FEW HUNDREDTHS IF THAT EVERY 6 HOURS. 850MB
TEMPS WILL GENERALLY RUN -17 TO -20C THROUGH TONIGHT. BETTER
CONVERGENCE WITH THE LOSS OF DAYTIME HEATING...AND THE APPROACH OF
YET ANOTHER SHORTWAVE WILL HELP BRING A LITTLE BETTER CHANCE OF
ACCUMULATING SNOW TO THE NW WIND SNOWBELTS. A COUPLE OF LOCATIONS IN
ALGER COUNTY COULD GET CLOSE TO ADVISORY SNOW TONIGHT IN CONVERGENT
BANDS OF LES SET UP IN ONE PLACE LONG ENOUGH. OTHERWISE COUNTY
AVERAGE IS RIGHT AROUND 3IN. SIMILAR TO THIS MORNING...CLOUD COVER
WILL MAKE ALL THE DIFFERENCE IN HOW COLD IT WILL GET TONIGHT. EXPECT
INTERIOR W HALF TO FALL INTO THE SINGLE DIGITS BELOW ZERO AGAIN.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 708 AM EST MON DEC 29 2014
EXPECT MAINLY MVFR CEILINGS/VIS THROUGH THE PERIOD...WITH SLIGHTLY
BETTER CONDITIONS AT SAW AND IWD FROM TIME TO TIME...AND SLIGHTLY
WORST CONDITIONS CONDITIONS AT CMX.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...PERSISTENT COOL NW WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS IS KEEPING LAKE EFFECT SNOW SHOWERS IN PLACE OVER
IWD AND CMX. ALTHOUGH THIS WIND DIRECTION IS NOT THE BEST FOR SAW TO
GET SNOW...OFF AND ON LIGHT SNOW SHOWERS OR FLURRIES REMAIN. EXPECT
DAYTIME HEATING TO HELP DISRUPT SOME OF THE STRONGER BANDS
TODAY...BEFORE ANOTHER UPPER LEVEL DISTURBANCE HELPS BOOST THE
POTENTIAL FOR LAKE EFFECT SNOW SHOWERS AT CMX ONCE AGAIN. AT THAT
POINT WINDS OVER N WI AND FAR W UPPER MI SHOULD BECOME MORE DIRECTLY
OUT OF THE W...SHUTTING OFF THE POTENTIAL FOR MUCH MORE THAN
FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 AM EST MON DEC 29 2014
LOOK FOR A BETTER CHANCE OF FREEZING SPRAY AND STRONG WINDS TUESDAY
NIGHT THROUGH THURSDAY MORNING.
THE OVERALL PATTERN LOOKS LIKE THIS...A RIDGE ACROSS THE UPPER GREAT
LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE
INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK
FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS
WILL BE AS A HUDSON BAY LOW SWINGS A TROUGH ACROSS LAKE SUPERIOR.
THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A
REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-40KTS ARE
STILL ANTICIPATED /ALONG WITH THE POTENTIAL FOR HEAVY FREEZING
SPRAY/ LATE TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW
TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN
SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE
ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE
TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...VOSS
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
603 AM EST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST MON DEC 29 2014
TODAY AND TONIGHT WILL BE MARKED BY PERSISTENT COOL NW FLOW...WITH
DAYTIME HIGHS FALLING ANOTHER 5F FROM WHAT WAS REALIZED SUNDAY. A
WEAK SFC TROUGH SET UP ACROSS THE CWA WILL CONTINUE TO BE ERODED FOR
ALL BUT FAR E UPPER MI/LAKE SUPERIOR AS VERY STRONG 1060-1062MB
ARCTIC HIGH PRESSURE OVER CENTRAL BRITISH COLUMBIA AND ALBERTA THIS
MORNING.
EXPECT TO SEE SOME TEMPORARY IMPROVING CONDITIONS LES WISE FROM
DAYBREAK THROUGH THE EARLY AFTERNOON HOURS AS THE INITIAL SHORTWAVE
SHIFTS A BIT FARTHER TO OUR N. A SECODARY TROUGH/SHORTWAVE IS
BRINGING HIGH CLOUDS TO THE S TIP OF THE CWA THIS MORNING.
PERSISTENT OFF AND ON LES WILL CONTINUE OUR HIGH POP/LOW QPF
SCENARIO...WITH ONLY A FEW HUNDREDTHS IF THAT EVERY 6 HOURS. 850MB
TEMPS WILL GENERALLY RUN -17 TO -20C THROUGH TONIGHT. BETTER
CONVERGENCE WITH THE LOSS OF DAYTIME HEATING...AND THE APPROACH OF
YET ANOTHER SHORTWAVE WILL HELP BRING A LITTLE BETTER CHANCE OF
ACCUMULATING SNOW TO THE NW WIND SNOWBELTS. A COUPLE OF LOCATIONS IN
ALGER COUNTY COULD GET CLOSE TO ADVISORY SNOW TONIGHT IN CONVERGENT
BANDS OF LES SET UP IN ONE PLACE LONG ENOUGH. OTHERWISE COUNTY
AVERAGE IS RIGHT AROUND 3IN. SIMILAR TO THIS MORNING...CLOUD COVER
WILL MAKE ALL THE DIFFERENCE IN HOW COLD IT WILL GET TONIGHT. EXPECT
INTERIOR W HALF TO FALL INTO THE SINGLE DIGITS BELOW ZERO AGAIN.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1157 PM EST SUN DEC 28 2014
NORTHWEST FLOW LAKE EFFECT WILL BE THE MAIN ITEM OF CONCERN. WITH A
STRONG INVERSION AROUND 3KFT ABOVE THE SURFACE...DON/T EXPECT THE
SNOW SHOWERS TO BECOME TOO STRONG AND HAVE KEPT VISIBILITIES IN THE
MVFR TO VFR RANGE AT KCMX/KIWD. LOW LEVEL WINDS DO LOOK TO BACK
SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE TROUGH THAT WILL THEN SHIFT
WINDS BACK TO THE NORTHWEST AROUND DAYBREAK. THUS...HAVE KEPT VSBYS
A LITTLE HIGHER AT KIWD WITH THOSE BACKING WINDS. ONCE THAT WEAK
TROUGH MOVES THROUGH...WOULD THINK THAT LIGHT LAKE EFFECT WOULD MOVE
BACK INTO THE SITE. OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION
FOR KSAW...VFR WILL CONTINUE THROUGH THE PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 AM EST MON DEC 29 2014
LOOK FOR A BETTER CHANCE OF FREEZING SPRAY AND STRONG WINDS TUESDAY
NIGHT THROUGH THURSDAY MORNING.
THE OVERALL PATTERN LOOKS LIKE THIS...A RIDGE ACROSS THE UPPER GREAT
LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE
INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK
FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS
WILL BE AS A HUDSON BAY LOW SWINGS A TROUGH ACROSS LAKE SUPERIOR.
THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A
REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-40KTS ARE
STILL ANTICIPATED /ALONG WITH THE POTENTIAL FOR HEAVY FREEZING
SPRAY/ LATE TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW
TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN
SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE
ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE
TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...VOSS
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
545 AM CST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM CST MON DEC 29 2014
THE SHORT TERM IS A BIT COMPLICATED. A COLD FRONT PASSED SOUTH
ACROSS THE CWA OVERNIGHT AND LIGHT SNOW HAS BROKEN OUT BEHIND IT.
MODELS ARE TRENDING LATER WITH THE BEGINNING OF SNOW. THE NAM AND
WRF...ALONG WITH THE HRRR INDICATE THAT THE SNOW ENTERING FROM THE
NORTH WILL HAVE A TOUGH TIME MAKING IT MUCH FARTHER SOUTH THAN
INTERSTATE 80 THIS AFTERNOON. AS THIS AREA OF SNOW STALLS AND
DISSIPATES...A MID-LEVEL PERTURBATION HEADS IN FROM THE WEST ACROSS
NORTHERN KANSAS ALONG WITH AN UPPER LEVEL JET MAXIMUM WILL HELP GET
SNOW GOING AGAIN...ESPECIALLY IN OUR FAR SOUTHWESTERN CWA. WE COULD
GET CLOSE TO THREE INCHES OF SNOW IN THESE AREAS...CONSIDERING A
GENERAL ENSEMBLE APPROACH TO MODEL QPF...ALONG WITH SNOW/LIQUID
WATER RATIOS 13 TO 1 FOR TONIGHT...WHICH IS FAIRLY TYPICAL. WENT
WITH A WINTER WEATHER ADVISORY IN OUR SOUTHWEST...CONSIDERING NOT
ONLY WE SHOULD JUST MEET SNOWFALL AMOUNT CRITERION...BUT THE
PRESSURE GRADIENT TODAY WILL BRING IN WIND FROM THE NORTH AT AROUND
20 MPH GUSTING TO 30 MPH. NUMERICAL MODELS ARE TRENDING LATER WITH
ENDING TIME...AND HAVE CONTINUED THIS ADVISORY INTO TUESDAY MORNING.
THIS COULD REDUCE VISIBILITY AS WELL. MY SNOW AMOUNTS MATCH UP
FAIRLY WELL WITH THE LATEST WPC GUIDANCE...WITH NEAR ONE INCH IN OUR
EAST TO THE 2 TO 4 INCH RANGE IN OUR WESTERN HALF OF THE CWA.
CONSIDERING THE GENERAL AGREEMENT BETWEEN THE NAM...NMM WRF...AND
SREF ENSEMBLES...I HAVE BUMPED UP CHANCES OF PRECIPITATION/SNOW
CONSIDERABLY...ESPECIALLY IN OUR SOUTHWEST FOR THIS AFTERNOON INTO
TONIGHT...BUT ALSO DELAYING THE ARRIVAL IN OUR SOUTHEAST A BIT
LONGER...CONSIDERING THAT THE NORTHERN BATCH OF SNOW SHOULD LOSE ITS
PUNCH BEFORE LONG. ALSO RAISED HIGH TEMPERATURES IN OUR NORTH
COMPARED TO THE PREVIOUS FORECAST... SINCE TEMPERATURES
ARE CURRENTLY 5 TO 7 DEGREES WARMER THAN THE EARLIER PREDICTED HIGH
FOR TODAY.
CONSIDERING THAT THE WIND SPEEDS WILL BE A BIT ELEVATED...EVEN LATE
TONIGHT...I DO NOT ANTICIPATE THAT LOWS WILL GET QUITE AS COOL AS
EARLIER PREDICTED...IN GENERAL...AND I HAVE BUMPED UP LOWS A COUPLE
OF DEGREES. I AM QUITE SKEPTICAL OF THE MID-LEVEL SKY COVER
ADVERTISED BY MODEL SOUNDINGS. MID-LEVEL SKY COVER IS FORECAST TO
HANG AROUND...DESPITE MUCH MORE DRY AND COLDER ARCTIC AIR IS MOVING
IN. I SUSPECT AT LEAST PARTIAL CLEARING COULD OCCUR IN OUR
NORTH/NORTHEAST BY THE END OF THE NIGHT. WITH THE WIND SPEEDS
ELEVATED...THIS ALONE SHOULD NOT HAVE AS MUCH OF AN EFFECT. HAVING
SAID THIS...WIND SPEEDS SHOULD BE HIGH ENOUGH TO NEED A WIND CHILL
ADVISORY ALONG AND NORTH OF HIGHWAY 6 LATE TONIGHT INTO TUESDAY
MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 530 AM CST MON DEC 29 2014
THE PRIMARY FORECAST CONCERN WILL CENTER AROUND THE BITTERLY COLD
TEMPERATURES TUESDAY THROUGH WEDNESDAY.
TUESDAY...SEVERAL FORECAST MODELS (00Z GEM...00Z ECMWF...06Z
NAM...AND A FEW WRF RUNS) ARE LINGERING THE LIGHT SNOW ACROSS OUR
SOUTHWESTERN ZONES INTO THE DAYLIGHT HOURS TUESDAY MORNING.
THEREFORE...HAVE INCREASED SNOW CHANCES TUESDAY MORNING ACROSS
SOUTHWESTERN ZONES...SOUTHWEST OF THE TRI-CITIES. SNOW WILL BE IN
THE PROCESS OF ENDING FROM NORTH TO SOUTH TUESDAY MORNING WITH ANY
ADDITIONAL ACCUMULATION AFTER SUNRISE TUESDAY MORNING LIKELY LESS
THAN ONE HALF INCH AND PRIMARILY CONFINED TO COUNTIES CURRENTLY
UNDER THE WINTER WEATHER ADVISORY. THE MORE WIDESPREAD ISSUE ACROSS
OUR FORECAST AREA WILL BE THE COLD AS WIND CHILL VALUES WILL LIKELY
FALL INTO THE -20 TO -30F RANGE ACROSS MOST OF OUR NEBRASKA COUNTIES
EXCEPT FOR THE SOUTHERN MOST TIER OF COUNTIES. OUR WIND CHILL
ADVISORY CRITERIA IS -20 TO -30F AND THEREFORE A WIND ADVISORY IS
NOW IN EFFECT FOR MOST OF OUR NEBRASKA COUNTIES FROM LATE TONIGHT
THROUGH TUESDAY MORNING. A NORTH WIND OF AROUND 15 TO 20 MPH GUSTING
TO AROUND 25 MPH ALONG WITH TUESDAY MORNING LOWS OF 0 TO -7F SHOULD
BE SUFFICIENT TO PUSH OUR WIND CHILLS DOWN INTO ADVISORY CRITERIA.
COLD AIR WILL CONTINUE TO FILTER INTO THE REGION THROUGHOUT THE DAY
MAKING IT HARD FOR TEMPERATURES TO RISE. IN ADDITION...MID TO HIGH
CLOUDS ARE EXPECTED THROUGH MUCH OF THE DAY AND ALONG WITH OUR
CURRENT SNOW COVER WILL ALSO MAKE IT DIFFICULT FOR TEMPERATURES TO
RISE. THEREFORE...WILL CALL FOR HIGHS ONLY IN THE 5 TO 10F RANGE.
TUESDAY NIGHT INTO WEDNESDAY...THE COLDEST NIGHT OF THE WEEK WILL
LIKELY BY TUESDAY NIGHT AS WE SEE CLEARING SKIES AND DECREASING
WINDS...WHICH WILL HELP LOWS FALL INTO THE -1 TO -10F RANGE ACROSS
THE FORECAST AREA. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THE WIND WILL BE
LIGHTER...THE AIR TEMPERATURES WILL BE COLDER SO THAT THE WIND CHILL
VALUES TUESDAY NIGHT/WEDNESDAY MORNING WILL LIKELY BE RATHER
COMPARABLE TO THE WIND CHILL VALUES EXPECTED TONIGHT INTO TUESDAY
MORNING. THE MODERATION IF YOU CAN CALL IT THAT WILL BEGIN DURING
THE DAY ON WEDNESDAY WITH A WEST SOUTHWEST WIND HELPING HIGHS TO
CLIMB BACK INTO THE TEENS.
THURSDAY THROUGH SUNDAY...A CUT OFF UPPER AREA OF LOW PRESSURE OVER
THE DESERT SOUTHWEST ON THURSDAY WILL SLOWLY TRACK ACROSS THE
SOUTHERN PLAINS FRIDAY AND SATURDAY...AND INTO THE MISSISSIPPI
VALLEY BY SUNDAY. MOST FORECAST MODELS KEEP THIS STORM TRACK FAR
ENOUGH SOUTH THAT WE WILL LIKELY BE DRY ACROSS OUR FORECAST AREA.
FOR THE SAKE OF A COUPLE OF OUTLYING MODELS WILL ALLOW THE SLIGHT
CHANCE OF SNOW ACROSS SOUTHEASTERN ZONES ON FRIDAY/FRIDAY NIGHT TO
REMAIN IN THE FORECAST...BUT CONFIDENCE IS LOW IN SEEING MEASURABLE
PRECIPITATION. THERE SHOULD BE SOME ADDITIONAL MODERATION IN
TEMPERATURES THURSDAY THROUGH SATURDAY AHEAD OF THE SOUTHERN STORM
SYSTEM WITH COLDER AIR FILTERING BACK IN BEHIND THE DEPARTING
SOUTHERN STORM SYSTEM ON SUNDAY. OVERALL...IT WILL REMAIN A COLD
PERIOD WITH HIGHS GENERALLY IN THE 20S FOR MOST AREAS...TO MAYBE
LOWER 30S SOUTH.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 541 AM CST MON DEC 29 2014
CONFIDENCE IF LOW FOR TIMING OF IFR CONDITIONS...BUT RATHER HIGH
THAT WE WILL EXPERIENCE IFR CONDITIONS AT SOME POINT. KEAR WILL
LAG BEHIND KGRI FOR INITIAL START OF SNOW THIS MORNING AS A BATCH
MOVES IN FROM THE NORTH...BUT SHOULD HANG ON TO SNOW LONGER AS THE
SNOW EVENTUALLY IS RELEGATED FARTHER SOUTHWEST FROM INCREASINGLY
DRY AIR BEING SHOVED SOUTH.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR NEZ039>041-046>049-060>064-072>077.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
NEZ082-083.
KS...WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
KSZ005-017-018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...WESELY
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
531 AM CST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM CST MON DEC 29 2014
THE SHORT TERM IS A BIT COMPLICATED. A COLD FRONT PASSED SOUTH
ACROSS THE CWA OVERNIGHT AND LIGHT SNOW HAS BROKEN OUT BEHIND IT.
MODELS ARE TRENDING LATER WITH THE BEGINNING OF SNOW. THE NAM AND
WRF...ALONG WITH THE HRRR INDICATE THAT THE SNOW ENTERING FROM THE
NORTH WILL HAVE A TOUGH TIME MAKING IT MUCH FARTHER SOUTH THAN
INTERSTATE 80 THIS AFTERNOON. AS THIS AREA OF SNOW STALLS AND
DISSIPATES...A MID-LEVEL PERTURBATION HEADS IN FROM THE WEST ACROSS
NORTHERN KANSAS ALONG WITH AN UPPER LEVEL JET MAXIMUM WILL HELP GET
SNOW GOING AGAIN...ESPECIALLY IN OUR FAR SOUTHWESTERN CWA. WE COULD
GET CLOSE TO THREE INCHES OF SNOW IN THESE AREAS...CONSIDERING A
GENERAL ENSEMBLE APPROACH TO MODEL QPF...ALONG WITH SNOW/LIQUID
WATER RATIOS 13 TO 1 FOR TONIGHT...WHICH IS FAIRLY TYPICAL. WENT
WITH A WINTER WEATHER ADVISORY IN OUR SOUTHWEST...CONSIDERING NOT
ONLY WE SHOULD JUST MEET SNOWFALL AMOUNT CRITERION...BUT THE
PRESSURE GRADIENT TODAY WILL BRING IN WIND FROM THE NORTH AT AROUND
20 MPH GUSTING TO 30 MPH. NUMERICAL MODELS ARE TRENDING LATER WITH
ENDING TIME...AND HAVE CONTINUED THIS ADVISORY INTO TUESDAY MORNING.
THIS COULD REDUCE VISIBILITY AS WELL. MY SNOW AMOUNTS MATCH UP
FAIRLY WELL WITH THE LATEST WPC GUIDANCE...WITH NEAR ONE INCH IN OUR
EAST TO THE 2 TO 4 INCH RANGE IN OUR WESTERN HALF OF THE CWA.
CONSIDERING THE GENERAL AGREEMENT BETWEEN THE NAM...NMM WRF...AND
SREF ENSEMBLES...I HAVE BUMPED UP CHANCES OF PRECIPITATION/SNOW
CONSIDERABLY...ESPECIALLY IN OUR SOUTHWEST FOR THIS AFTERNOON INTO
TONIGHT...BUT ALSO DELAYING THE ARRIVAL IN OUR SOUTHEAST A BIT
LONGER...CONSIDERING THAT THE NORTHERN BATCH OF SNOW SHOULD LOSE ITS
PUNCH BEFORE LONG. ALSO RAISED HIGH TEMPERATURES IN OUR NORTH
COMPARED TO THE PREVIOUS FORECAST... SINCE TEMPERATURES
ARE CURRENTLY 5 TO 7 DEGREES WARMER THAN THE EARLIER PREDICTED HIGH
FOR TODAY.
CONSIDERING THAT THE WIND SPEEDS WILL BE A BIT ELEVATED...EVEN LATE
TONIGHT...I DO NOT ANTICIPATE THAT LOWS WILL GET QUITE AS COOL AS
EARLIER PREDICTED...IN GENERAL...AND I HAVE BUMPED UP LOWS A COUPLE
OF DEGREES. I AM QUITE SKEPTICAL OF THE MID-LEVEL SKY COVER
ADVERTISED BY MODEL SOUNDINGS. MID-LEVEL SKY COVER IS FORECAST TO
HANG AROUND...DESPITE MUCH MORE DRY AND COLDER ARCTIC AIR IS MOVING
IN. I SUSPECT AT LEAST PARTIAL CLEARING COULD OCCUR IN OUR
NORTH/NORTHEAST BY THE END OF THE NIGHT. WITH THE WIND SPEEDS
ELEVATED...THIS ALONE SHOULD NOT HAVE AS MUCH OF AN EFFECT. HAVING
SAID THIS...WIND SPEEDS SHOULD BE HIGH ENOUGH TO NEED A WIND CHILL
ADVISORY ALONG AND NORTH OF HIGHWAY 6 LATE TONIGHT INTO TUESDAY
MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 530 AM CST MON DEC 29 2014
THE PRIMARY FORECAST CONCERN WILL CENTER AROUND THE BITTERLY COLD
TEMPERATURES TUESDAY THROUGH WEDNESDAY.
TUESDAY...SEVERAL FORECAST MODELS (00Z GEM...00Z ECMWF...06Z
NAM...AND A FEW WRF RUNS) ARE LINGERING THE LIGHT SNOW ACROSS OUR
SOUTHWESTERN ZONES INTO THE DAYLIGHT HOURS TUESDAY MORNING.
THEREFORE...HAVE INCREASED SNOW CHANCES TUESDAY MORNING ACROSS
SOUTHWESTERN ZONES...SOUTHWEST OF THE TRI-CITIES. SNOW WILL BE IN
THE PROCESS OF ENDING FROM NORTH TO SOUTH TUESDAY MORNING WITH ANY
ADDITIONAL ACCUMULATION AFTER SUNRISE TUESDAY MORNING LIKELY LESS
THAN ONE HALF INCH AND PRIMARILY CONFINED TO COUNTIES CURRENTLY
UNDER THE WINTER WEATHER ADVISORY. THE MORE WIDESPREAD ISSUE ACROSS
OUR FORECAST AREA WILL BE THE COLD AS WIND CHILL VALUES WILL LIKELY
FALL INTO THE -20 TO -30F RANGE ACROSS MOST OF OUR NEBRASKA COUNTIES
EXCEPT FOR THE SOUTHERN MOST TIER OF COUNTIES. OUR WIND CHILL
ADVISORY CRITERIA IS -20 TO -30F AND THEREFORE A WIND ADVISORY IS
NOW IN EFFECT FOR MOST OF OUR NEBRASKA COUNTIES FROM LATE TONIGHT
THROUGH TUESDAY MORNING. A NORTH WIND OF AROUND 15 TO 20 MPH GUSTING
TO AROUND 25 MPH ALONG WITH TUESDAY MORNING LOWS OF 0 TO -7F SHOULD
BE SUFFICIENT TO PUSH OUR WIND CHILLS DOWN INTO ADVISORY CRITERIA.
COLD AIR WILL CONTINUE TO FILTER INTO THE REGION THROUGHOUT THE DAY
MAKING IT HARD FOR TEMPERATURES TO RISE. IN ADDITION...MID TO HIGH
CLOUDS ARE EXPECTED THROUGH MUCH OF THE DAY AND ALONG WITH OUR
CURRENT SNOW COVER WILL ALSO MAKE IT DIFFICULT FOR TEMPERATURES TO
RISE. THEREFORE...WILL CALL FOR HIGHS ONLY IN THE 5 TO 10F RANGE.
TUESDAY NIGHT INTO WEDNESDAY...THE COLDEST NIGHT OF THE WEEK WILL
LIKELY BY TUESDAY NIGHT AS WE SEE CLEARING SKIES AND DECREASING
WINDS...WHICH WILL HELP LOWS FALL INTO THE -1 TO -10F RANGE ACROSS
THE FORECAST AREA. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THE WIND WILL BE
LIGHTER...THE AIR TEMPERATURES WILL BE COLDER SO THAT THE WIND CHILL
VALUES TUESDAY NIGHT/WEDNESDAY MORNING WILL LIKELY BE RATHER
COMPARABLE TO THE WIND CHILL VALUES EXPECTED TONIGHT INTO TUESDAY
MORNING. THE MODERATION IF YOU CAN CALL IT THAT WILL BEGIN DURING
THE DAY ON WEDNESDAY WITH A WEST SOUTHWEST WIND HELPING HIGHS TO
CLIMB BACK INTO THE TEENS.
THURSDAY THROUGH SUNDAY...A CUT OFF UPPER AREA OF LOW PRESSURE OVER
THE DESERT SOUTHWEST ON THURSDAY WILL SLOWLY TRACK ACROSS THE
SOUTHERN PLAINS FRIDAY AND SATURDAY...AND INTO THE MISSISSIPPI
VALLEY BY SUNDAY. MOST FORECAST MODELS KEEP THIS STORM TRACK FAR
ENOUGH SOUTH THAT WE WILL LIKELY BE DRY ACROSS OUR FORECAST AREA.
FOR THE SAKE OF A COUPLE OF OUTLYING MODELS WILL ALLOW THE SLIGHT
CHANCE OF SNOW ACROSS SOUTHEASTERN ZONES ON FRIDAY/FRIDAY NIGHT TO
REMAIN IN THE FORECAST...BUT CONFIDENCE IS LOW IN SEEING MEASURABLE
PRECIPITATION. THERE SHOULD BE SOME ADDITIONAL MODERATION IN
TEMPERATURES THURSDAY THROUGH SATURDAY AHEAD OF THE SOUTHERN STORM
SYSTEM WITH COLDER AIR FILTERING BACK IN BEHIND THE DEPARTING
SOUTHERN STORM SYSTEM ON SUNDAY. OVERALL...IT WILL REMAIN A COLD
PERIOD WITH HIGHS GENERALLY IN THE 20S FOR MOST AREAS...TO MAYBE
LOWER 30S SOUTH.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1158 PM CST SUN DEC 28 2014
TRENDS ARE LATER FOR ARRIVAL OF SNOW FROM THE MID-LEVEL SYSTEM
COMING THROUGH. EXPECT IFR CONDITIONS FOR A GOOD PORTION OF DAY ON
MONDAY...AND SNOW WILL LIKELY CONTINUE WELL INTO THE EVENING AS
CEILINGS AND VISIBILITY IMPROVE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR NEZ039>041-046>049-060>064-072>077.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
NEZ082-083.
KS...WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
KSZ005-017-018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...WESELY
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
944 AM EST MON DEC 29 2014
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH ACROSS THE AREA TODAY. BEHIND THE
FRONT...HIGH PRESSURE WILL BUILD ACROSS THE NATIONS MID SECTION
AND EXTEND INTO THE GREAT LAKES AND OHIO VALLEY THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE FOR MINOR CHANGES. LATEST HRRR CONTINUE TO SHOW SOME SNOW
SHOWERS ACROSS NW PA THIS AFTERNOON. WILL CONTINUE WITH A 20 POP.
ORIGINAL...HIGH CLOUDS DRIFTING EAST OVERNIGHT HOWEVER SATELLITE
SHOWS STRATUS DEVELOPING ACROSS THE CENTRAL AND EAST LAKESHORE
COUNTIES AND A LARGE AREA OF STRATUS ACROSS LOWER MI AND NORTH OF
LAKE ERIE DRIFTING SOUTH. ELSEWHERE SKIES MOSTLY CLEAR. FOR THE
EARLY MORNING AM EXPECTING STRATUS TO CONTINUE TO EXPAND AS LOW
LEVEL LOW COMES OFF THE LAKE. THE STRATUS ACROSS LOWER MI AND
CANADA NORTH OF LAKE ERIE HAS TENDED TO DISSIPATE ON THE SOUTHERN
SIDE SLOWING ITS PROGRESSION. FOLLOWING THE NAM 925MB RH ONE WOULD
EXPECT THE STRATUS TO EITHER MOVE IN FROM THE NORTHWEST OR DEVELOP
ACROSS THE AREA HOWEVER THERE ARE PLENTY OF HOLES AND WITH DRY AIR
ABOVE...ANY MIXING WOULD TEND TO ALLOW MORE HOLES TO DEVELOP. FOR
NOW AWAY FROM THE LAKE...WILL BEGIN WITH PC AND THEN TRANSITION TO
MC OR PS. GUIDANCE HIGHS IN THE LOW TO MID 30S LOOK FINE WITH ONLY
MINOR ADJUSTMENTS.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL CONTINUE TO NOSE INTO THE AREA TONIGHT THROUGH
WEDNESDAY AS IT DROPS THROUGH THE CENTRAL PLAINS. GIVEN ITS TRACK
HOWEVER COLD ADVECTION WILL CONTINUE THROUGH THE PERIOD WITH BOTH
THE NAM AND GFS SHOWING -16 TO -18C BY WEDNESDAY 12Z. OUTSIDE OF
ANY LAKE EFFECT THE AIRMASS REMAINS FAIRLY DRY THROUGH THE SHORT
TERM PERIOD. GIVEN THE TEMP FALL HOWEVER WILL CONTINUE WITH CHANCE
POPS ALL ALONG THE LAKESHORE COUNTIES FROM LORAIN CO EAST
BEGINNING TUESDAY AFTERNOON...INCREASING TO LIKELY ASHTABULA ERIE
CRAWFORD TUESDAY NIGHT AS LAKE-850MB TEMP DIFFERENCE BECOMES
ENOUGH FOR MODERATE INSTABILITY AS SHOWN ON BUFKIT KERI FORECAST
SOUNDING. WILL CONTINUE WITH CHANCE POPS WEDNESDAY. WINDS BACK
TO SOUTHWEST WEDNESDAY NIGHT TAKING ANY BANDS OFFSHORE. THURSDAY
NIGHT THE GFS SHOWS ANOTHER TROF DROPPING SOUTH ACROSS THE LAKES
BRINGING MOISTURE TO THE AREA. WILL BRING CHANCE POPS BACK TO THE
NORTHERN COUNTIES WITH HIGHEST POPS IN THE SNOWBELT. TEMPS
GENERALLY BELOW NORMAL.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LONG RANGE MODELS HAD SOME DIFFERENCES TO THEIR SOLUTIONS ON
SATURDAY WITH THE EUROPEAN BEING THE DRIEST COMPARED TO THE WET GFS
MODEL. LATEST RUN OF THE EUROPEAN AT 00Z IS NOW INDICATING A WETTER
SOLUTION IN LINE WITH THE GFS SO WILL BE LEANING IN THE DIRECTION OF
SPREADING PRECIPITATION INTO THE REGION DURING THE DAY SATURDAY. I
GUESS UNTIL I SEE SOME CONSISTENCY IN THE MODELS FOR WARMING THINGS
UP ON SATURDAY...I WILL NOT GET TOO CRAZY IN RAISING TEMPERATURES
FOR HIGHS. LATEST GUIDANCE SUGGESTS A FAIRLY BRISK SOUTH TO
SOUTHWESTERLY FLOW ON SATURDAY INDICATING TEMPERATURES WILL BE MUCH
WARMER THAN WE HAVE CURRENTLY FORECAST. SO...I GUESS I WOULD EXPECT
TEMPERATURES TRENDING UPWARD OVER THE NEXT FEW DAYS IF MODELS ARE
PERSISTENT.
ONCE SURFACE LOW GOES BY ON SUNDAY...COLD AIR ADVECTION WILL RETURN
TO THE REGION. THIS WILL LIKELY SET UP SOME LAKE EFFECT SNOW SHOWERS
BY SUNDAY NIGHT INTO MONDAY. DEPENDING ON THE TIMING OF THE LOW
PASSAGE...SOME COULD BEGIN AS EARLY AS LATE SUNDAY AFTERNOON.
COLD AIR ADVECTION LOOKS LIKE IT WILL BE A GLANCING BLOW AS HIGH
PRESSURE BUILDS SOUTHEAST ACROSS THE GREAT LAKES BY THE MIDDLE OF
THE WEEK.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
STRATUS BETWEEN 2500 AND 3500 FEET CONTINUES TO DEVELOP ACROSS THE
CENTRAL AND EAST LAKESHORE COUNTIES AS LOW LEVEL MOISTURE REMAINS
TRAPPED ACROSS THE AREA. EXPECTING THIS CLOUD COVER TO GRADUALLY
DISSIPATE THIS AFTERNOON INTO THE EVENING HOURS. HOWEVER...SOME
HIGH CLOUDS WILL SPREAD INTO THE REGION THIS AFTERNOON AND EVENING
SO NO REAL LONG STRETCH OF CLEAR SKIES EXPECTED TODAY. WINDS
SHOULD BE LIGHT NORTH TO NORTHWEST BECOMING LIGHT AND VARIABLE
OVERNIGHT.
.OUTLOOK...AREAS OF NON VFR CEILINGS LATE MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.MARINE...
LAKE IS EXPECTED TO BE FAIRLY QUIET TODAY AND TONIGHT BUT WINDS ARE
EXPECTED TO PICK UP SPEED BY TUESDAY AFTERNOON INTO WEDNESDAY. FLOW
WILL GRADUALLY SHIFT AROUND TO THE SOUTHWEST BY WEDNESDAY NIGHT AND
INCREASE EVEN FURTHER. I WOULD IMAGINE THAT AT SOME POINT WE ARE
GOING TO NEED A SMALL CRAFT ADVISORY TUESDAY AND POSSIBLY GALES BY
WEDNESDAY NIGHT. SO WILL INCLUDE A MENTION OF GALE POTENTIAL IN THE
HAZARDOUS WEATHER OUTLOOK. WINDS STAY PRETTY GUSTY OUT OF THE WEST
SOUTHWEST INTO THURSDAY WHEN THEY EVENTUALLY DIMINISH.
UNFORTUNATELY...SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED GOING
INTO FRIDAY AS WINDS DO NOT DIMINISH ENOUGH.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK/KUBINA
SHORT TERM...TK
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
452 AM CST MON DEC 29 2014
.DISCUSSION...
EARLY THIS MORNING...SATELLITE SHOWED THAT LOW CLOUDS COVERED THE
MIDSOUTH. ANY CLEARING HAS STALLED AND THE LOW CLOUDS WERE EXPANDING
IN COVERAGE. TEMPERATURES WERE MOSTLY IN THE 30S EXCEPT FOR LOWER
40S ACROSS PORTIONS OF NORTHEAST MS. WINDS WERE NORTHERLY ABOUT 5 TO
10 MPH. PATCHY LIGHT RAIN LINGERED FROM PORTIONS OF SOUTHWEST TN
INTO NORTH MS.
A STRONG SURFACE HIGH PRESSURE OF ABOUT 1058 MB WILL EXTEND FROM
SOUTHWEST CANADA TO THE MIDSOUTH TODAY. LOW CLOUDS WILL SLOWLY
DECREASE FROM THE WEST ACROSS PORTIONS OF NORTHEAST AR...BUT LOW
CLOUDS WILL PERSIST EAST OF THE MS RIVER ALL DAY. IN ADDITION...HIGH
LEVEL CLOUDS WILL SPREAD IN FROM THE WEST. TEMPERATURES WILL BE HELD
DOWN BY THE CLOUDS AND WILL BE BELOW NORMAL. BASED ON THE HRRR AND
NAM...KEPT IN AREAS OF DRIZZLE AND A SLIGHT CHANCE OF RAIN FROM
SOUTHWEST TN ALONG THE TN RIVER INTO PORTIONS OF NORTHEAST MS EARLY
THIS MORNING.
FOR TONIGHT...DID NOT CLEAR THE SKIES QUITE AS FAST AS SOME OF THE
GUIDANCE INDICATES WITH 925 MB WINDS FROM THE NORTHEAST HELPING TO
HOLD IN THE LOW CLOUDS ESPECIALLY EAST OF THE MS RIVER.
OTHERWISE...COLD HIGH PRESSURE WILL EXTEND INTO THE MIDSOUTH FROM
THE NORTH WITH PRECIPITATION FREE CONDITIONS.
SUNSHINE WILL RETURN TO THE MIDSOUTH TUESDAY AS THE STRONG SURFACE
HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. HIGH TEMPERATURES WILL
REMAIN BELOW NORMAL TUESDAY.
FOR WEDNESDAY...A SURFACE HIGH OF 1040 MB IS FORECAST TO BE CENTERED
OVER OK AND WILL DOMINATE MIDSOUTH WEATHER. SKIES WILL BE MOSTLY
SUNNY BUT IT WILL BE COLD.
WEDNESDAY AND THURSDAY MORNINGS WILL SEE LOW TEMPERATURES DIP INTO
THE 20S AREAWIDE WITH POSSIBLY SOME UPPER TEENS ACROSS THE EXTREME
NORTHERN LOCATIONS.
NEW YEARS DAY WILL CONTINUE COLD WITH INCREASING CLOUDS FROM THE
WEST DURING THE DAY. THE BLENDED GUIDANCE INDICATES A SLIGHT CHANCE
OF RAIN SPREADING INTO PORTIONS OF EAST CENTRAL AR AND NORTH MS
BY LATE AFTERNOON AS OVERRUNNING DEVELOPS.
THE OVERRUNNING PATTERN WILL STRENGTHEN THURSDAY NIGHT WITH A WARM
FRONT ALONG THE GULF COAST. A CLOSED UPPER LEVEL LOW OVER THE
SOUTHWESTERN UNITED STATES WILL MOVE SLOWLY EASTWARD. RAIN IS
FORECAST TO SPREAD ACROSS THE MIDSOUTH. A WINTRY MIXTURE OF
PRECIPITATION CONSISTING OF SLEET...RAIN...AND POSSIBLY FREEZING
RAIN IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING ACROSS PORTIONS
OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...INTO PORTIONS OF
WEST TENNESSEE. THE AFFECTED AREA IS MAINLY ALONG AND NORTH OF A
LINE FROM HARRISBURG ARKANSAS TO COVINGTON TENNESSEE TO SAVANNAH
TENNESSEE. AT THIS TIME...ANY ACCUMULATIONS ARE EXPECTED TO BE
LIGHT. THE PRECIPITATION IS EXPECTED TO CHANGE TO ALL RAIN BY MID-
MORNING FRIDAY. BRIEF SLEET MAY OCCUR JUST TO THE SOUTH OF THIS AREA
THURSDAY NIGHT BEFORE CHANGING TO RAIN WITH TEMPERATURES ABOVE
FREEZING.
FRIDAY INTO SATURDAY LOOK VERY WET FOR THE MIDSOUTH. THE UPPER LEVEL
LOW WILL SLOWLY APPROACH FROM THE WEST WITH THE WARM FRONT TO THE
SOUTH PUSHING ONLY SLOWLY NORTHWARD. MODELS DIFFER ON THE
DEVELOPMENT OF A SURFACE LOW ALONG THE FRONT. PRECIPITABLE WATER WILL
BE ON THE INCREASE WITH VALUES REACHING GREATER THAN 1.5 INCHES
ACROSS PORTIONS OF THE REGION BY FRIDAY NIGHT / SATURDAY. ELEVATED
INSTABILITY WILL ALSO INCREASE AS THE CLOSED UPPER LOW AND SOUTHWARD
EXTENDING UPPER LEVEL TROUGH APPROACHES. SCATTERED THUNDERSTORMS CAN
BE EXPECTED BY FRIDAY NIGHT AND CONTINUING INTO SATURDAY / SATURDAY
NIGHT. RAIN MAY BE LOCALLY HEAVY...HELD OFF MENTIONING THIS THREAT
IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW UNTIL CONFIDENCE INCREASES.
IT IS POSSIBLE THUNDERSTORMS TO OUR SOUTH COULD CUT US OFF FROM THE
GREATER MOISTURE AND RAINFALL. THE UPPER LEVEL TROUGH / ASSOCIATED
COLD FRONT IS FORECAST THROUGH THE REGION SATURDAY NIGHT WITH A
LINGERING CHANCE OF RAIN SUNDAY.
JCL
&&
.AVIATION...
06Z TAF CYCLE
IFR TO MVFR CIGS ARE EXPECTED OVERNIGHT WITH PATCHY FOG. MODEL
GUIDANCE HAS BEEN OVERLY AGGRESSIVE WITH CLEARING CLOUDS OUT FOR
SEVERAL RUNS NOW. WILL SIDE WITH THE MORE PESSIMISTIC GUIDANCE
AND KEEP CLOUDS AROUND FOR MOST OF THE DAY...ESPECIALLY AT TUP
WHERE CONDITIONS WILL LIKELY REMAIN MVFR AT BEST. PATCHY 3-5SM BR
IS POSSIBLE..ESPECIALLY TOWARD SUNRISE. CONFIDENCE IS HIGHEST
THAT JBR WILL SEE VFR CONDITIONS DURING THE AFTERNOON HOURS. MID
CLOUDS WILL RETURN TOMORROW NIGHT.
WINDS EAST TO NORTHEAST AROUND 5 KTS.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
857 AM CST MON DEC 29 2014
.UPDATE...
QUICK MORNING UPDATE TO EXTEND DENSE FOG ADVISORY FARTHER WEST
BASED ON LATEST OBSERVATIONAL TRENDS. HRRR AND RUC VISIBILITY
PROGS SHOW THIS FOG HANGING ON THROUGH LATE MORNING.
ADDITIONALLY...HAVE SEEN SOME REPORTS ON SOCIAL MEDIA OF LIGHT
ICING ON BRIDGES IN BRAZOS COUNTY /AROUND THE BRYAN AREA/ AND
LOCALIZED FREEZING FOG WILL ALSO BE POSSIBLE IN THIS AREA FOR A
BRIEF PERIOD THIS MORNING BEFORE TEMPERATURES WARM ABOVE FREEZING.
HUFFMAN
&&
.PREV DISCUSSION... /ISSUED 408 AM CST MON DEC 29 2014/
DISCUSSION...
LOW CLOUDS, DRIZZLE & FOG ACROSS EASTERN 2/3 OF THE CWA SHOULD
BEGIN TO ERODE LATE THIS MORNING. MIGHT TAKE A BIT LONGER ACROSS
NE PARTS...WHICH LIKE SUNDAY...COULD PLAY HAVOC WITH HIGH TEMPS
DEPENDING ON TIMING & BREAKS OF SUN.
LEADING EDGE OR ARCTIC AIRMASS NOW SPILLING INTO NCNTL PARTS OF
THE COUNTRY WILL BEGIN FILTERING INTO SE TX ON TUE. IT`LL BE A
GRADUAL PROCESS WITH CAA CONTINUING WED/THU. ONE THING FUTURE
SHIFTS WILL NEED TO KEEP A CLOSE AN EYE ON IS PRECIP CHANCES NEW
YEARS EVE. BOTH THE 00Z & 06Z RUNS OF THE NAM12 SHOW FAIRLY ROBUST
MOISTURE ASCENT OVER COOLER SFC AIRMASS WITH INCREASING -RA
COVERAGE THRU THE EVNG AND OVERNIGHT HOURS WED. THIS IS 12-18 HOURS
EARLIER THAN WHAT GLOBAL MODELS/GUIDANCE HAVE BEEN AND ARE STILL
INDICATING. TYPICALLY GIVE MORE FCST WEIGHT TO NAM12 IN THESE AIRMASSES
AND WENT AHEAD AND BUMPED POPS UP WED NIGHT...BUT THEY MAY STILL
BE SIGNIFICANTLY UNDERDONE.
COLDEST DAY OF THE WEEK SHOULD BE NEW YEARS DAY (THURS) WITH EXPECTED
CLOUDS/PRECIP LIMITING ANY WARM-UP.
COASTAL TROF TAKES SHAPE LATE THURS AND FRI AS SFC HIGH PRES MOVES
OFF TO THE EAST AND UPPER TROF SLOWLY APPROACHES FROM THE WEST.
COMBINATION OF UPGLIDE, MESSY SW FLOW ALOFT & COASTAL TROF WILL
PROVIDE CONTINUED GOOD CHANCES OF PRECIP THRU SAT AFTN. FWIW THIS
FAR OUT - THE 00Z GUIDANCE DOESN`T BRING THE WARM SECTOR NEARLY
AS FAR INLAND AS PAST RUNS. PACIFIC FRONT CLEARS THE PRECIP OUT
LATE SAT AS UPPER TROF DEPARTS. 47
MARINE...
GENERALLY LIGHT N/NELY WINDS TO PREVAIL THE NEXT DAY (OR SO) BEFORE
STRENGTHENING TUES IN RESPONSE TO THE UPPER LEVEL STORM SYSTEM DEEP-
ENING OUT TO THE WEST. WE COULD SEE SCEC/SCA FLAGS FOR THE UPPER TX
COASTAL WATERS BY TUES NIGHT...LINGERING ON INTO LATE THURS. S/SELY
WINDS PROGGED TO RETURN FRI AS A WARM FRONT MOVES ASHORE.
AVIATION...
FOGGY START TO THE DAY WITH LIFR VIS/CIGS PREVAILING ACROSS THE SRN
TWO THIRDS OF THE FA. THESE CONDITIONS COULD BE SLOW TO CLEAR GIVEN
THE VERY LIGHT WINDS JUST ABOVE THE SFC...BUT WE SHOULD SEE VFR CIG
BY THE AFTN. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 55 39 51 34 42 / 0 0 0 10 20
HOUSTON (IAH) 57 42 56 37 48 / 0 0 0 0 20
GALVESTON (GLS) 54 49 56 43 51 / 0 0 0 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 11 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: BRAZORIA...BRAZOS...FORT BEND...
GALVESTON...GRIMES...HARRIS...HOUSTON...LIBERTY...MADISON...
MATAGORDA...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
WALKER...WALLER.
GM...NONE.
&&
$$
DISCUSSION...99
AREA FORECAST DISCUSSION
NWS RENO NV
242 PM PST MON DEC 29 2014
.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH THROUGH THE AREA TONIGHT. SNOWFALL
IS POSSIBLE WITH POTENTIAL TRAVEL IMPACTS FOR THE TUESDAY MORNING
COMMUTE ALONG THE HIGHWAY 395 CORRIDOR. STRONG WINDS ARE EXPECTED
TO PRODUCE ROUGH CONDITIONS ON AREA LAKES ALONG WITH POSSIBLE
AREAS OF BLOWING SNOW. TEMPERATURES WILL BE BITTER COLD WITH WIND
CHILLS IN THE SINGLE DIGITS AND NEGATIVE VALUES HEADING INTO THE
NEW YEAR. A MILDER PATTERN WILL RETURN FOR THE WEEKEND.
&&
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
VISIBLE SATELLITE IMAGERY SHOWING A COLD UPPER LOW ACROSS THE
PACIFIC NORTHWEST WITH COOLING IR COLD TOPS ALONG A STRONG COLD
FRONT OVER SOUTHERN OREGON. THIS FRONT WILL QUICKLY DRIVE SOUTH
THROUGH NORTHERN NEVADA TONIGHT INTO TUESDAY MORNING PROVIDING THE
POTENTIAL FOR A FEW INCHES OF SNOWFALL AND BITTER COLD HEADING INTO
THE NEW YEAR.
HI-RES MESOSCALE AND GLOBAL MODELS ARE BEGINNING TO CLUE INTO THE
FORMATION OF BANDED SNOWFALL CREATED BY STRONG LOW LEVEL
FRONTOGENESIS AND MOISTURE IN A REGION OF FAVORABLE MICROPHYSICS FOR
ICE CRYSTAL GROWTH. THESE COLD TEMPERATURES WILL MAKE FOR LIGHT
AND FLUFFY SNOW. SOME DISAGREEMENT ON TIMING BUT LARGELY LOOKING
FOR SNOWFALL IN THE RENO/CARSON CITY REGION AS EARLY 8PM BUT THE
MOST FAVORABLE WINDOW LOOKS TO BE BETWEEN 10PM-4AM. A WINTER
WEATHER ADVISORY HAS BEEN POSTED FOR THE SIERRA FRONT WHICH
INCLUDES THE HWY 395 CORRIDOR SOUTH THROUGH MINDEN AND
GARDNERVILLE. THE ADVISORY ALSO COVERS PORTIONS OF WESTERN MINERAL
AND SOUTHERN LYON COUNTY. GENERALLY LOOKING FOR SNOWFALL IN THE
1-2" RANGE FROM RENO TO CARSON CITY WITH HIGHER AMOUNTS SOUTH
WHERE UPSLOPE FORCING WILL ADD ADDITIONAL LIFT. LOCATIONS ALONG
THE EASTERN SLOPES OF THE CARSON RANGE, EASTERN ALPINE CO,
NORTHERN MONO COUNTY COULD SEE MORE IN THE 2-4" RANGE. SLIDERS ARE
NOTORIOUSLY DIFFICULT SYSTEMS TO FORECAST SO WILL PUT FORECAST
CONFIDENCE IN SNOW AMOUNTS IN THE MEDIUM CATEGORY.
THE OTHER IMPACTS WITH THIS SYSTEM WILL BE SOME GUSTY CONDITIONS
BEHIND THE FRONT AS A STRONG PRESSURE GRADIENT DEVELOPS ACROSS
WESTERN NEVADA AND THE SIERRA. EXPECTING TO SEE SUSTAINED WINDS IN
THE 15-25 MPH RANGE WITH GUSTS UP TO 40-45 MPH OUT OF THE EAST WHICH
PUTS THIS JUST BELOW ADVISORY CRITERIA ACROSS WESTERN NEVADA. HAVE
HOWEVER POSTED A LAKE WIND ADVISORY FOR PYRAMID LAKE AND A WIND
ADVISORY ACROSS THE TAHOE BASIN. EXPECTING HAZARDOUS BOATING
CONDITIONS ON AREA LAKES WITH GUSTS NEAR 45 MPH EXPECTED IN THE
TAHOE BASIN WITH HIGHEST WAVES ALONG THE ATYPICAL WESTERN SHORES.
WINDS WILL SHARPLY INCREASE IN ELEVATION WITH VERY STRONG WINDS
EXPECTED MAINLY ABOVE 8,500 FEET WHERE GUSTS BETWEEN 80-100+ MPH ARE
POSSIBLE. THIS MAY ALSO POSE THE RISK FOR TREE FALLS ACROSS THE
TAHOE BASIN PARTICULARLY FOR TREES WEAKENED FROM THE PAST WIND
EVENT. THE SAME STRONG WINDS HOLD TRUE ACROSS HIGH TERRAIN THROUGH
MONO COUNTY BUT THE STRONGEST WINDS WILL REMAIN OVER THE CREST AND
ALONG THE WESTERN SLOPES OF THE SIERRA WHERE VERY STRONG DOWNSLOPE
WINDS LOOK FAVORABLE.
OTHERWISE, LOOKING FOR SNOW SHOWERS TO LINGER THROUGH TUESDAY
AFTERNOON ESPECIALLY ACROSS ALPINE AND MONO COUNTY WHERE UPSLOPE
FORCING SETS UP. AN INCH OR TWO IS POSSIBLE ACROSS THE TAHOE BASIN
AND MONO COUNTY OUTSIDE OF AREAS OF LAKE ENHANCED SNOWFALL. STRONG
WINDS MAY ALSO PRODUCE AREAS OF BLOWING SNOW AND REDUCED VISIBILITY.
FUENTES
.(WEDNESDAY AND THURSDAY)..
MAIN CHANGE TO THE WEDNESDAY-THURSDAY TIME FRAME WAS LOWERING MAX
AND MIN TEMPS BY A FEW DEGREES EACH, WITH THE INCREASED
EXPECTATION OF ACCUMULATING SNOW WITH THE UPPER LOW PASSING
THROUGH TONIGHT AND TUESDAY. THE PRESENCE OF SNOW COVER WILL
STRENGTHEN THE VALLEY INVERSION FURTHER AND KEEP HIGHS ONLY IN THE
LOWER-MID 20S WEDNESDAY. STRONG NE-E WINDS WILL CONTINUE OVER THE
SIERRA RIDGES WITH GUSTS 75-85 MPH, WHILE SURFACE WIND GUSTS WILL
GENERALLY RANGE FROM 25-35 MPH EXCEPT NEAR 40 MPH AROUND TAHOE
WEDNESDAY MORNING. THESE WINDS WILL DECREASE LATER IN THE DAY AS
THE UPPER LOW MOVES FROM SOUTHEAST CA TO ARIZONA.
NEW YEARS EVE WILL BE QUITE COLD WITH TEMPERATURES BY MIDNIGHT
DROPPING TO THE LOWER TEENS FOR RENO-CARSON CITY AND SINGLE DIGITS
AROUND TAHOE. ALTHOUGH WINDS WILL BE DECREASING, WIND CHILLS COULD
STILL BE NEAR ZERO FOR WESTERN NV AND -10 DEGREES FOR THE FIRST
COUPLE HOURS OF 2015. THE EARLY MORNING LOWS FOR NEW YEARS DAY ARE
LIKELY TO BE AROUND 5 DEGREES FOR URBAN AREAS OF WESTERN NV, AND
BELOW ZERO AWAY FROM THE MAIN CITIES AND IN THE SIERRA VALLEYS.
ON THURSDAY, THE CORE OF THE COLD AIR MASS WILL MOVE AWAY FROM
WESTERN NV BUT WITH INVERSION STILL IN PLACE, HIGHS ARE LIKELY TO
REMAIN BELOW FREEZING. LIGHTER WINDS ARE EXPECTED WITH DRY
CONDITIONS PREVAILING THROUGH THE FIRST DAY OF 2015. MJD
.LONG TERM (FRIDAY-MONDAY)...
THE MOTTO FOR THE LONG TERM WILL BE "WELCOME TO INVERSION CITY".
GUIDANCE CONSENSUS SHOWS RIDGING JUST OFF THE WEST COAST THROUGH THE
WEEKEND WHICH YIELDS WARMING TEMPERATURES AT 700MB. COUPLED WITH A
SURFACE HIGH OVER THE INTERMOUNTAIN WEST THIS RESULTS IN AN
INVERSION PATTERN FOR THE VALLEYS OF WESTERN NV AND NORTHEAST CA,
WITH LIGHT WINDS, LIMITED MIXING, AND POTENTIAL AIR POLLUTION
BUILDUPS. TEMPERATURES IN VALLEYS WILL WARM EACH DAY BUT AT A MUCH
SLOWER RATE COMPARED TO THE MOUNTAINS. IF WE GET SUFFICIENT SNOWFALL
TONIGHT THEN THOSE INVERSIONS COULD BE STRONGER WITH POTENTIAL FOR
SPOTS OF FREEZING FOG IN NORMALLY PRONE AREAS.
UNFORTUNATELY I`M REALLY NOT SEEING MEANINGFUL STORM POTENTIAL
THROUGH AT LEAST MONDAY AS THE RIDGE BLOCKS PACIFIC STORMS FROM
IMPACTING CA/NV. THERE ARE SOME SIGNS OF THE RIDGE BREAKING DOWN OR
BEING UNDERCUT MID/LATE NEXT WEEK ALLOWING AN INCREASED CHANCE OF
ATMOSPHERIC RIVERS LANDFALLING ON THE WEST COAST. BUT OF COURSE
PREDICTABILITY OF THESE PATTERN CHANGES 7-10 DAYS OUT IS QUITE
LIMITED. CS
&&
.AVIATION...
FORECAST CONFIDENCE IN TODAY`S TAFS IS MEDIUM, WITH UNCERTAINTIES IN
TIMING AND INTENSITY OF TONIGHT`S BAND OF SNOW. THESE KIND OF SLIDER
STORMS ARE A CHALLENGE TO PREDICT SO SNOWFALL POTENTIAL REMAINS ONLY
MEDIUM CONFIDENCE AS WELL. HIGH RESOLUTION SIMULATIONS (HRRR) ARE
SHOWING A FAST MOVING BAND OF -SN DEVELOPING FROM AAT-LOL AROUND
SUNDOWN AND THEN DROPPING SOUTHWARD INTO RNO/CXP 4-10Z, TRK/TVL/MEV
AROUND 6-12Z, AND AFTER 12Z AT MMH. IN SUCH A STRONGLY FORCED
SITUATION THE HRRR USUALLY DOES REASONABLY WELL SO WE`LL FOLLOW FOR
THE TAFS.
PERIODS OF MVFR/IFR -SN LIKELY AT RNO/CXP/TRK/TVL/MEV TONIGHT
YIELDING UP TO 2 INCHES OF FLUFFY SNOW. THERE`S ABOUT A 20% CHANCE
WE COULD SEE BRIEF PERIODS OF HEAVIER SNOW, 1/2SM VISIBILITY TYPE
STUFF, BUT PREDICTING TIMING ON THAT IS TRICKY. GUSTY N/NE WINDS
WILL RESULTING IN BLOWING SNOW AS WELL. CLOUDS WILL RESULT IN
TERRAIN OBSCURATION TONIGHT THROUGH TOMORROW.
THE POST-FRONTAL NORTHEAST WINDS TUESDAY WILL BE PRONOUNCED AND
GUSTY, WITH A FRESH SUSTAINED 15-25 KTS EAST/NORTHEAST WIND WITH
GUSTS 25-30 KTS. CXP WHICH IS PRONE TO NE FLOW EVENTS, WILL LIKELY SEE
PERIODS OF STRONGER SUSTAINED WINDS. RIDGE LEVEL GUSTS OF 60-70 KTS
FORECAST TOMORROW, INCREASING TUESDAY NIGHT INTO WEDNESDAY. DUE TO
THE UNUSUAL NE WIND DIRECTION, THAT WILL LEAD TO TURBULENCE
ESPECIALLY WEST OF ANY MOUNTAINS DUE TO MOUNTAIN WAVE ACTIVITY. CS
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...LAKE WIND ADVISORY FROM 7 AM TO 7 PM PST TUESDAY FOR PYRAMID
LAKE IN NVZ004.
WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY NVZ002.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST
TUESDAY NVZ001.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 10 AM PST
TUESDAY NVZ003.
CA...WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY CAZ072.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1057 AM MST MON DEC 29 2014
.UPDATE...
ISSUED AT 937 AM MST MON DEC 29 2014
ADDED THE REMAINING ZONES ON THE PLAINS...SOUTHERN EL PASO COUNTY
AND THE UPPER ARKANSAS RIVER VALLEY TO THE ADVISORY. HRRR...RAP
AND NAM CONTINUE TO SHOW A BROAD AREA OF ISENTROPIC UPGLIDE OVER
THE REGION. AS THE DISTURBANCE APPROACHES SOUTHER COLORADO THIS
AFTERNOON...BROAD SOUTH TO EAST FLOW WILL RISE OVER THE DEEPENING
COLD AIR TO CREATE A PROLONGED PERIOD OF LIGHT TO OCCASIONALLY
MODERATE SNOW. NOT SURE HOW FAR SOUTH SNOW WILL REACH IN EASTERN
LAS ANIMAS AND BACA COUNTIES...BUT IT IS LOOKING AS IF THE
NORTHERN PORTION OF THESE ZONES WILL GET SEVERAL INCHES OF SNOW.
UPGLIDE WILL ALSO REACH SOUTHERN EL PASO COUNTY AND CURRENT TRENDS
SUGGEST THE UPGLIDE WILL BE ABLE TO OVERCOME THE DRYING EFFECTS
DUE TO THE DOWNSLOPE NORTHERLY WINDS. UPGLIDE OVER CHAFFEE AND
LAKE COUNTIES WILL ALLOW FOR A FEW INCHES OF SNOW INT HE VALLEY
BOTTOMS...CREATING SOME SLICK ROADS.
CONTEMPLATING WIND CHILL ADVISORY LATER TONIGHT AND TOMORROW
MORNING FOR PORTIONS OF THE PLAINS AND INTERSTATE 25 CORRIDOR.
CURRENT GRIDS HAVE MARGINAL CRITERIA FOR THIS WELL ADVERTISED
COLD SNAP. -PGW--
UPDATE ISSUED AT 520 AM MST MON DEC 29 2014
BASED ON LAST COUPLE OF RUNS OF THE HRRR....WHICH SHOW GREATEST
SNOWFALL POTENTIAL OVER SE PUEBLO COUNTY AND PORTIONS OF THE
PLAINS N OF THE ARKANSAS...HAVE DECIDED TO ADD THESE COUNTIES TO
THE SNOW ADVISORY. HRRR SHOWS QPF MAXES OVER SRN PUEBLO COUNTY
AND PROWERS COUNTY. THIS MATCHES OTHER MODEL TRENDS AS WELL. SRN
EL PASO LOOKS LIKE IT WILL BE LEFT OUT OF THE HEAVIER SNOW
BANDS...SO WILL LEAVE IT OUT OF THE ADVISORY FOR NOW. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM MST MON DEC 29 2014
...FRIGID AIR HEADED OUR WAY ALONG WITH SOME SNOW...
THE COLD FRONT IS NOW PUSHING SWD THROUGH NE CO AND WILL CONTINUE TO
ADVANCE TO THE SOUTH THIS MORNING. THE FRONT SHOULD BE OVER THE
PALMER DVD BY 15Z AND THEN CHARGE SWD ALONG ALL OF OUR ERN PLAINS BY
18Z. SINCE THE PRECIP WILL ACCOMPANY THE FRONT...HAVE PUSHED BACK
TIMING OF POPS A BIT BUT BY 18Z THERE SHOULD BE FAIRLY GOOD COVERAGE
OF SNOW OVER OUR AREA. THE COLD AIR WILL BE DEEP ENOUGH TO SPILL INTO
THE SAN LUIS VALLEY TONIGHT...SO EVERYONE WILL GET A DOSE OF THE
FRIGID CONDITIONS. TEMPS TODAY WILL START OUT IN THE TEENS AND
SINGLE DIGITS...AND HIGH TEMPS WILL BE REALIZED EARLY AS STRONG CAA
WILL BE THE RULE THROUGH TODAY. MAY NOT GET OUT OF THE TEENS OVER
THE NRN I-25 CORRIDOR...AND REST OF THE SE PLAINS WILL ONLY BE IN THE
20S.
MODELS HAVE BEEN EXTREMELY CONSISTENT BOTH IN TIME AND ACROSS THE
BOARD IN TERMS OF EXPECTED QPF FROM THIS EVENT. HIGH SNOW-LIQUID
RATIOS MAY PUSH THINGS A BIT HIGHER THAN FORECAST...BUT IN GENERAL
THE MODEL GUIDANCE IS SHOWING 3 TO 6 INCH TOTALS FOR THE LOWLANDS
AND 6 TO 8 INCH TOTALS FOR THE MOUNTAINS. HAVE ADDED FREMONT COUNTY
AND THE ARKANSAS RIVER CANYON TO OUR SNOW ADVISORIES...ALONG WITH THE
NORTHERN SAN LUIS VALLEY...WHERE THE MODELS HAVE CONSISTENTLY BEEN
SHOWING DECENT SNOW AMOUNTS FOR TONIGHT. ALSO EXTENDED THE CENTRAL
MTS ADVISORY THROUGH TUESDAY MORNING AS ADDITIONAL ACCUMULATIONS
LOOK LIKELY THERE. SNOW AMOUNTS EVERYWHERE LOOK TO BE BORDERLINE
ADVISORY LEVELS. FROM AN IMPACT PERSPECTIVE...IT WILL BE A TWO EDGED
SWORD SINCE THERE WILL STILL BE PLENTY OF HOLIDAY TRAFFIC BUT WITH
THE HIGH SNOW-LIQUID RATIOS AND COLD AIR...ROAD CONDITIONS MAY NOT
BE QUITE AS BAD. GIVEN THE POTENTIAL FOR SLIGHTLY HIGHER SNOW
TOTALS...AN ADVISORY LOOKS LIKE THE BEST COURSE OF ACTION AT THIS
TIME. REMAINING ZONES/AREAS THAT WILL REQUIRE CLOSE ATTENTION ARE
THE UPPER ARKANSAS VALLEY...IF COLD AIR CONTINUES TO PUSH TO THE
WEST THIS EVENING...AND THE HIGHER TERRAIN OF PUEBLO COUNTY OVER SRN
AND WRN PORTIONS OF THE ZONE.
TONIGHT...LIGHT SNOW WILL CONTINUE AND WILL SPREAD OUT EWD TOWARD
THE KS BORDER. AMOUNTS COULD APPROACH LOW-END ADVISORY LEVELS BY TUE
MORNING. H7 TEMPS CONTINUE TO PLUMMET TO NR MINUS 23 DEGREES...WHICH
TYPICALLY ONLY HAPPENS A COUPLE TIMES EACH WINTER. THE ONLY THING
THAT WILL KEEP THE LOWER ARKANSAS VALLEY FROM HITTING LOWS MINUS 20
DEGREES OR LOWER WILL BE THE EXTENSIVE CLOUDS AND LIGHT SNOW. THIS
WILL SERVE TO KEEP US ON THE `WARM` SIDE...ONLY ZERO TO MINUS 10
DEGREES BY EARLY TUE MORNING. THERE WILL BE BORDERLINE WIND-CHILL
ADVISORY READINGS OVER THE MTS...SAN LUIS VALLEY...AND PIKES PEAK
REGION BUT IT LOOKS FAIRLY SPOTTY AT THIS TIME SO WILL HOLD OFF ON
ISSUING ANY WIND CHILL ALERTS. THE COLDEST AIR STILL LOOKS TO BE ON
TUESDAY AND TUE NIGHT. SO...BREAK OUT LOTS OF LAYERS AND PREPARE FOR
THE COLD! ROSE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 312 AM MST MON DEC 29 2014
...VERY COLD TUESDAY...THEN WHERE DOES THE UPPER LOW GO LATE IN THE
WEEK?...
TUESDAY...
IT WILL BE VERY COLD ACROSS THE REGION. IT APPEARS NOW THAT ALL
AREAS ON THE PLAINS WILL ONLY SEE HIGH TEMPS IN THE POSITIVE
SINGLE DIGITS. AREAS ON THE PALMER DIVIDE MAY SEE A FEW MAX TEMPS
IN THE NEGATIVE SINGLE DIGITS. I SHOULD NOTE THAT MOS IS A FEW
DEGREES COOLER THAN CURRENT GRIDS...HOWEVER SPC PLUME VIEWER
PRODUCTS LEAN MORE TOWARDS CURRENT NDFD TEMPS...AND CURRENT
FORECASTED HIGH TEMPS MATCH UP WITH SURROUNDING WFO/S. IT WILL BE
CLOUDY OVER THE PLAINS TUESDAY AND SNOW IS LIKELY MOST IF NOT ALL
LOWER ELEVATIONS...ESPECIALLY IN THE MORNING. IT APPEARS THE SNOW
THAT FALLS ON THE PLAINS WILL BE LIGHT...WITH ONLY AN INCH OR TWO
OF NEW SNOW POSSIBLE DURING THE DAY TUESDAY. HIGHER AMOUNTS WILL
BE POSSIBLE ON THE EAST SLOPES OF THE S MTNS.
WIND CHILL READINGS TUESDAY WILL BE THE MAIN CONCERN AS I EXPECT
THESE VALUES WILL RANGE BETWEEN -10 AND -20F MOST OF THE DAY.
MTNS AND VALLEYS WILL SEE SOME LIGHT SNOW...ESPECIALLY C MTNS.
ACCUMS SHOULD BE LIGHT. THE ARCTIC AIR WILL LIKELY GET INTO THE
UPPER ARK RVR VALLEY...HOWEVER THE SAN LUIS VALLEY WILL NOT SEE
THE BRUNT OF THE COLD AIR...AND MAX TEMPS IN THE SLV SHOULD BE IN
THE UPPER TEENS.
TUESDAY NIGHT...
VERY COLD TEMPERATURES ARE CERTAIN. HOW COLD IS THE QUESTION. MIN
TEMPS WILL BE DEPENDENT ON HOW MUCH CLOUDINESS (OR LACK THEREOF) WE
HAVE OVER THE REGION. IT WILL ALSO BE DEPENDENT ON SNOW COVER. FOR
NOW THE NDFD MIN TEMPS RANGE BETWEEN -5 TO -15F OVER THE PLAINS.
IF IT CLEARS OUT AND THERE IS WIDESPREAD SNOW COVER...THEN THESE
TEMPS COULD BE 5 TO 10F COLDER THAN CURRENT FORECASTED LOWS.
WEDNESDAY...
WE START TO MODERATE ACROSS THE REGION...ALTHOUGH IT STILL WILL BE
COLD. I DO NOT EXPECT ANY LOCATIONS IN THE CWA TO GET ABOVE FREEZING
THIS DAY. WARMEST TEMPS WILL LIKELY OCCUR IN THE MID ARK RVR VALLEY
(SALIDA TO CANON CITY) WHERE TEMPS WILL GET INTO THE MID 20S. I
EXPECT THE PLAINS WILL PRIMARILY BE IN THE TEENS WITH A 20S JUST
EAST OF THE MTNS. EXCEPT FOR SOME SHOWERS ALONG THE CONTDVD...IT
WILL BE DRY.
THURSDAY INTO THE WEEKEND...
CONCERN TURN TOWARDS THE CLOSED LOW THAT WILL BE N ARIZ THURSDAY
MORNING. LATEST GUIDANCE IS INDICATING A BIT MORE FAVORABLE TRACK
FOR THE SOUTHERN TIER OF THE FCST AREA...ESPECIALLY THE SAN JUANS
FOR LATE WED INTO EARLY FRIDAY. HAVE INCREASED POPS OVER THE SAN
JUAN REGION THU AND FRI...AND HAVE EXTENDED POPS EASTWARD ACROSS THE
S TIER OF THE PLAINS FRIDAY INTO SATURDAY.
OVER THE REMAINDER OF THE REGION...TEMPS WILL MODIFY WITH TEMPS
RETURNING TO SLIGHTLY BELOW NORMAL TEMPERATURES (~40F PLAINS)
/HODANISH
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1049 AM MST MON DEC 29 2014
KCOS AND KPUB...ARCTIC AIR MASS HAS ARRIVED AND WILL STAY OVER THE
REGION THROUGH THE TAF PERIOD AND BEYOND. A DISTURBANCE MOVING
ACROSS SOUTHERN COLORADO WILL RESULT IN ISENTROPIC UPGLIDE THIS
AFTERNOON AND INTO THE EARLY EVENING. ANTICIPATE THIS WILL BE THE
PERIOD OF HEAVIEST SNOW AT THESE TAF SITES. BY MID EVENING...SNOW
INTENSITY WILL DECREASE WITH PERIODS OF LIGHT SNOW FROM THE WEAK
UPSLOPE FLOW. ANTICIPATE IFR CONDITIONS THROUGH THE PERIOD.
KALS...ARCTIC AIR TO THE EAST WILL FILTER INTO THE SAN LUIS VALLEY
LATER IN THE AFTERNOON. TAFS CURRENTLY HAVE MFVR CONDITIONS
DEVELOPING IN THE EARLY EVENING ASSOCIATED WITH THE ARCTIC AIR.
SOME LIGHT SNOW WILL BE POSSIBLE. MVFR CEILINGS WILL CONTINUE
THROUGH THE END OF THE TAF PERIOD AND LIKELY INTO THE AFTERNOON.
--PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ065-069-
072>080-083-086>089-093>099.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ058>063-
081-082-084-085.
&&
$$
UPDATE...PGW
SHORT TERM...ROSE
LONG TERM...HODANISH
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
948 AM MST MON DEC 29 2014
.UPDATE...
ISSUED AT 937 AM MST MON DEC 29 2014
ADDED THE REMAINING ZONES ON THE PLAINS...SOUTHERN EL PASO COUNTY
AND THE UPPER ARKANSAS RIVER VALLEY TO THE ADVISORY. HRRR...RAP
AND NAM CONTINUE TO SHOW A BROAD AREA OF ISENTROPIC UPGLIDE OVER
THE REGION. AS THE DISTURBANCE APPROACHES SOUTHER COLORADO THIS
AFTERNOON...BROAD SOUTH TO EAST FLOW WILL RISE OVER THE DEEPENING
COLD AIR TO CREATE A PROLONGED PERIOD OF LIGHT TO OCCASIONALLY
MODERATE SNOW. NOT SURE HOW FAR SOUTH SNOW WILL REACH IN EASTERN
LAS ANIMAS AND BACA COUNTIES...BUT IT IS LOOKING AS IF THE
NORTHERN PORTION OF THESE ZONES WILL GET SEVERAL INCHES OF SNOW.
UPGLIDE WILL ALSO REACH SOUTHERN EL PASO COUNTY AND CURRENT TRENDS
SUGGEST THE UPGLIDE WILL BE ABLE TO OVERCOME THE DRYING EFFECTS
DUE TO THE DOWNSLOPE NORTHERLY WINDS. UPGLIDE OVER CHAFFEE AND
LAKE COUNTIES WILL ALLOW FOR A FEW INCHES OF SNOW INT HE VALLEY
BOTTOMS...CREATING SOME SLICK ROADS.
CONTEMPLATING WIND CHILL ADVISORY LATER TONIGHT AND TOMORROW
MORNING FOR PORTIONS OF THE PLAINS AND INTERSTATE 25 CORRIDOR.
CURRENT GRIDS HAVE MARGINAL CRITERIA FOR THIS WELL ADVERTISED
COLD SNAP. -PGW--
UPDATE ISSUED AT 520 AM MST MON DEC 29 2014
BASED ON LAST COUPLE OF RUNS OF THE HRRR....WHICH SHOW GREATEST
SNOWFALL POTENTIAL OVER SE PUEBLO COUNTY AND PORTIONS OF THE
PLAINS N OF THE ARKANSAS...HAVE DECIDED TO ADD THESE COUNTIES TO
THE SNOW ADVISORY. HRRR SHOWS QPF MAXES OVER SRN PUEBLO COUNTY
AND PROWERS COUNTY. THIS MATCHES OTHER MODEL TRENDS AS WELL. SRN
EL PASO LOOKS LIKE IT WILL BE LEFT OUT OF THE HEAVIER SNOW
BANDS...SO WILL LEAVE IT OUT OF THE ADVISORY FOR NOW. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM MST MON DEC 29 2014
...FRIGID AIR HEADED OUR WAY ALONG WITH SOME SNOW...
THE COLD FRONT IS NOW PUSHING SWD THROUGH NE CO AND WILL CONTINUE TO
ADVANCE TO THE SOUTH THIS MORNING. THE FRONT SHOULD BE OVER THE
PALMER DVD BY 15Z AND THEN CHARGE SWD ALONG ALL OF OUR ERN PLAINS BY
18Z. SINCE THE PRECIP WILL ACCOMPANY THE FRONT...HAVE PUSHED BACK
TIMING OF POPS A BIT BUT BY 18Z THERE SHOULD BE FAIRLY GOOD COVERAGE
OF SNOW OVER OUR AREA. THE COLD AIR WILL BE DEEP ENOUGH TO SPILL INTO
THE SAN LUIS VALLEY TONIGHT...SO EVERYONE WILL GET A DOSE OF THE
FRIGID CONDITIONS. TEMPS TODAY WILL START OUT IN THE TEENS AND
SINGLE DIGITS...AND HIGH TEMPS WILL BE REALIZED EARLY AS STRONG CAA
WILL BE THE RULE THROUGH TODAY. MAY NOT GET OUT OF THE TEENS OVER
THE NRN I-25 CORRIDOR...AND REST OF THE SE PLAINS WILL ONLY BE IN THE
20S.
MODELS HAVE BEEN EXTREMELY CONSISTENT BOTH IN TIME AND ACROSS THE
BOARD IN TERMS OF EXPECTED QPF FROM THIS EVENT. HIGH SNOW-LIQUID
RATIOS MAY PUSH THINGS A BIT HIGHER THAN FORECAST...BUT IN GENERAL
THE MODEL GUIDANCE IS SHOWING 3 TO 6 INCH TOTALS FOR THE LOWLANDS
AND 6 TO 8 INCH TOTALS FOR THE MOUNTAINS. HAVE ADDED FREMONT COUNTY
AND THE ARKANSAS RIVER CANYON TO OUR SNOW ADVISORIES...ALONG WITH THE
NORTHERN SAN LUIS VALLEY...WHERE THE MODELS HAVE CONSISTENTLY BEEN
SHOWING DECENT SNOW AMOUNTS FOR TONIGHT. ALSO EXTENDED THE CENTRAL
MTS ADVISORY THROUGH TUESDAY MORNING AS ADDITIONAL ACCUMULATIONS
LOOK LIKELY THERE. SNOW AMOUNTS EVERYWHERE LOOK TO BE BORDERLINE
ADVISORY LEVELS. FROM AN IMPACT PERSPECTIVE...IT WILL BE A TWO EDGED
SWORD SINCE THERE WILL STILL BE PLENTY OF HOLIDAY TRAFFIC BUT WITH
THE HIGH SNOW-LIQUID RATIOS AND COLD AIR...ROAD CONDITIONS MAY NOT
BE QUITE AS BAD. GIVEN THE POTENTIAL FOR SLIGHTLY HIGHER SNOW
TOTALS...AN ADVISORY LOOKS LIKE THE BEST COURSE OF ACTION AT THIS
TIME. REMAINING ZONES/AREAS THAT WILL REQUIRE CLOSE ATTENTION ARE
THE UPPER ARKANSAS VALLEY...IF COLD AIR CONTINUES TO PUSH TO THE
WEST THIS EVENING...AND THE HIGHER TERRAIN OF PUEBLO COUNTY OVER SRN
AND WRN PORTIONS OF THE ZONE.
TONIGHT...LIGHT SNOW WILL CONTINUE AND WILL SPREAD OUT EWD TOWARD
THE KS BORDER. AMOUNTS COULD APPROACH LOW-END ADVISORY LEVELS BY TUE
MORNING. H7 TEMPS CONTINUE TO PLUMMET TO NR MINUS 23 DEGREES...WHICH
TYPICALLY ONLY HAPPENS A COUPLE TIMES EACH WINTER. THE ONLY THING
THAT WILL KEEP THE LOWER ARKANSAS VALLEY FROM HITTING LOWS MINUS 20
DEGREES OR LOWER WILL BE THE EXTENSIVE CLOUDS AND LIGHT SNOW. THIS
WILL SERVE TO KEEP US ON THE `WARM` SIDE...ONLY ZERO TO MINUS 10
DEGREES BY EARLY TUE MORNING. THERE WILL BE BORDERLINE WIND-CHILL
ADVISORY READINGS OVER THE MTS...SAN LUIS VALLEY...AND PIKES PEAK
REGION BUT IT LOOKS FAIRLY SPOTTY AT THIS TIME SO WILL HOLD OFF ON
ISSUING ANY WIND CHILL ALERTS. THE COLDEST AIR STILL LOOKS TO BE ON
TUESDAY AND TUE NIGHT. SO...BREAK OUT LOTS OF LAYERS AND PREPARE FOR
THE COLD! ROSE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 312 AM MST MON DEC 29 2014
...VERY COLD TUESDAY...THEN WHERE DOES THE UPPER LOW GO LATE IN THE
WEEK?...
TUESDAY...
IT WILL BE VERY COLD ACROSS THE REGION. IT APPEARS NOW THAT ALL
AREAS ON THE PLAINS WILL ONLY SEE HIGH TEMPS IN THE POSITIVE
SINGLE DIGITS. AREAS ON THE PALMER DIVIDE MAY SEE A FEW MAX TEMPS
IN THE NEGATIVE SINGLE DIGITS. I SHOULD NOTE THAT MOS IS A FEW
DEGREES COOLER THAN CURRENT GRIDS...HOWEVER SPC PLUME VIEWER
PRODUCTS LEAN MORE TOWARDS CURRENT NDFD TEMPS...AND CURRENT
FORECASTED HIGH TEMPS MATCH UP WITH SURROUNDING WFO/S. IT WILL BE
CLOUDY OVER THE PLAINS TUESDAY AND SNOW IS LIKELY MOST IF NOT ALL
LOWER ELEVATIONS...ESPECIALLY IN THE MORNING. IT APPEARS THE SNOW
THAT FALLS ON THE PLAINS WILL BE LIGHT...WITH ONLY AN INCH OR TWO
OF NEW SNOW POSSIBLE DURING THE DAY TUESDAY. HIGHER AMOUNTS WILL
BE POSSIBLE ON THE EAST SLOPES OF THE S MTNS.
WIND CHILL READINGS TUESDAY WILL BE THE MAIN CONCERN AS I EXPECT
THESE VALUES WILL RANGE BETWEEN -10 AND -20F MOST OF THE DAY.
MTNS AND VALLEYS WILL SEE SOME LIGHT SNOW...ESPECIALLY C MTNS.
ACCUMS SHOULD BE LIGHT. THE ARCTIC AIR WILL LIKELY GET INTO THE
UPPER ARK RVR VALLEY...HOWEVER THE SAN LUIS VALLEY WILL NOT SEE
THE BRUNT OF THE COLD AIR...AND MAX TEMPS IN THE SLV SHOULD BE IN
THE UPPER TEENS.
TUESDAY NIGHT...
VERY COLD TEMPERATURES ARE CERTAIN. HOW COLD IS THE QUESTION. MIN
TEMPS WILL BE DEPENDENT ON HOW MUCH CLOUDINESS (OR LACK THEREOF) WE
HAVE OVER THE REGION. IT WILL ALSO BE DEPENDENT ON SNOW COVER. FOR
NOW THE NDFD MIN TEMPS RANGE BETWEEN -5 TO -15F OVER THE PLAINS.
IF IT CLEARS OUT AND THERE IS WIDESPREAD SNOW COVER...THEN THESE
TEMPS COULD BE 5 TO 10F COLDER THAN CURRENT FORECASTED LOWS.
WEDNESDAY...
WE START TO MODERATE ACROSS THE REGION...ALTHOUGH IT STILL WILL BE
COLD. I DO NOT EXPECT ANY LOCATIONS IN THE CWA TO GET ABOVE FREEZING
THIS DAY. WARMEST TEMPS WILL LIKELY OCCUR IN THE MID ARK RVR VALLEY
(SALIDA TO CANON CITY) WHERE TEMPS WILL GET INTO THE MID 20S. I
EXPECT THE PLAINS WILL PRIMARILY BE IN THE TEENS WITH A 20S JUST
EAST OF THE MTNS. EXCEPT FOR SOME SHOWERS ALONG THE CONTDVD...IT
WILL BE DRY.
THURSDAY INTO THE WEEKEND...
CONCERN TURN TOWARDS THE CLOSED LOW THAT WILL BE N ARIZ THURSDAY
MORNING. LATEST GUIDANCE IS INDICATING A BIT MORE FAVORABLE TRACK
FOR THE SOUTHERN TIER OF THE FCST AREA...ESPECIALLY THE SAN JUANS
FOR LATE WED INTO EARLY FRIDAY. HAVE INCREASED POPS OVER THE SAN
JUAN REGION THU AND FRI...AND HAVE EXTENDED POPS EASTWARD ACROSS THE
S TIER OF THE PLAINS FRIDAY INTO SATURDAY.
OVER THE REMAINDER OF THE REGION...TEMPS WILL MODIFY WITH TEMPS
RETURNING TO SLIGHTLY BELOW NORMAL TEMPERATURES (~40F PLAINS)
/HODANISH
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 312 AM MST MON DEC 29 2014
AN ARCTIC FRONT WILL PUSH SOUTHWARD INTO SE CO BETWEEN 15 AND 18Z
THIS MORNING. THIS WILL LEAD TO A PROLONGED PERIOD OF MVFR TO IFR
CONDITIONS...AND OCCASIONAL LIFR CONDITIONS...THROUGH TUESDAY. KCOS
AND KPUB WILL SEE THESE CONDITIONS DEVELOP FROM 16-18Z AS LIGHT SNOW
BECOMES MORE WIDESPREAD AND PERSISTENT THROUGH THIS AFTERNOON. WINDS
WILL BE MODERATE FROM THE NE DURING THIS PERIOD. KALS WILL SEE
CONDITIONS DETERIORATE A BIT LATER TODAY AS IT WILL TAKE A WHILE FOR
THE COLD AIR TO SPILL OVER INTO THE SAN LUIS VALLEY...BUT SIMILAR
MVFR-IFR CONDITIONS ARE EXPECTED IN THE HIGH VALLEYS OVERNIGHT INTO
TUE MORNING. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ065-069-
072>080-083-086>089-093>099.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ059-
061>063-085.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ058-060-
081-082-084.
&&
$$
UPDATE...PGW
SHORT TERM...ROSE
LONG TERM...HODANISH
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
200 PM EST MON DEC 29 2014
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THAT MUCH OF THE CONUS IS
NOW UNDER BROAD LONGWAVE TROUGHING...AS THE RIDGE THAT WAS ALONG THE
EASTERN SEABOARD HAS BEEN DEAMPLIFIED BY SHORTWAVE ENERGY PASSING
OFF THE CAROLINA COAST AND PUSHED SOUTHEAST INTO THE WESTERN
ATLANTIC. THE CENTRAL/SOUTHERN FLORIDA PENINSULA IS STILL SOMEWHAT
UNDER THE SUBSIDENCE OF THIS RIDGE...BUT HEIGHTS HAVE CERTAINLY COME
DOWN ACROSS THE PENINSULA DURING THE PAST 24 HOURS. THE MOST
INTERESTING FEATURE IN THE UPPER LEVELS IS A STRONG PIECE OF
SHORTWAVE/JET ENERGY DIVING DOWN THE PACIFIC COAST. THIS ENERGY IS
PROGGED TO EVOLVE INTO A LARGE CUTOFF LOW OVER THE SOUTHWESTERN
STATES BY THE MIDDLE OF THE WEEK AND THEN SLOWLY EJECT EASTWARD
ACROSS THE SOUTHERN PLAINS.
29/12Z KTBW SOUNDING PROFILE SHOWS THAT ALTHOUGH THE RIDGE ALOFT IS
WEAKENING...IT STILL HAS SOME INFLUENCE ON THE REGION. AN ASSOCIATED
SUBSIDENCE INVERSION IS EVIDENT AROUND 850MB WITH QUITE A DRY COLUMN
ABOVE IN THE MID LAYERS OF THE ATMOSPHERE.
AT THE SURFACE...ATLANTIC HIGH PRESSURE RIDGES BACK OVER THE CENTRAL
AND SOUTHERN FL PENINSULA...WHILE AT THE SAME TIME A COLD FRONT
SLOWLY CRAWLS SLOWLY THROUGH THE EASTERN GULF OF MEXICO. THE FLOW
BETWEEN THESE 2 FEATURES IS PROVIDING ABUNDANT LOW LEVEL MOISTURE TO
THE REGION. THESE RICH DEWPOINTS (LOWER 70S AT BUOY 42036) ARE
ADVECTING OVER THE LOWER 60S TEMPERATURE SHELF WATERS OF EASTERN
APALACHEE BAY AND RESULTED IN AREAS OF DENSE SEA FOG EARLIER TODAY.
THIS FOG HAS SINCE MIGRATED MOSTLY TO THE NORTH OF OUR COASTAL
ZONES...BUT AM EXPECTING IT TO REDEVELOP LATER THIS EVENING AND
OVERNIGHT...AND ALSO LIKELY TO SEE THE AREAL COVERAGE OF THE SEA FOG
EXPAND SOUTHWARD OVERNIGHT. THIS EXPANSION CONTINUES TO BE SHOWN
BY THE SREF AND ALSO THE ENSEMBLE LOCAL SUITE OF HIGH RESOLUTION
GUIDANCE.
&&
.SHORT TERM (REST OF TODAY THROUGH TUESDAY)...
REST OF TODAY...
STILL CALLING IT A "MIX OF SUN AND CLOUDS" AS A SCT CUMULUS FIELD
HAS BECOME WELL ESTABLISHED THIS AFTERNOON. INLAND LOCATIONS...
ESPECIALLY ALONG AND SOUTH OF THE I-4 CORRIDOR ARE NOW IN THE LOWER
80S...WHILE THINGS HOLD IN THE 70S AT THE BEACHES DUE TO THE ONSHORE
COMPONENT TO THE WIND. THE COLD FRONT WILL BE MAKING VERY SLOW
PROGRESS EASTWARD INTO THE EVENING BUT WILL FAIL TO REACH OUR VERY
NORTHERN COUNTIES UNTIL LATER TONIGHT. EVEN STILL...A FEW SHOWERS
AHEAD OF THE BOUNDARY MAY REACH LEVY COUNTY AND THE NORTHERN COASTAL
WATERS BY EARLY THIS EVENING...HOWEVER THE BETTER SHOWER CHANCES
WILL EXIST FOR LEVY/CITRUS COUNTIES LATER EVENING AND OVERNIGHT.
TONIGHT...
THE APPROACH OF ONE FINAL PIECE OF WEAK SHORTWAVE ENERGY OVER THE
NORTHERN GULF COAST WILL FINALLY GIVE THE FRONT THE PUSH IT NEEDS TO
ENTER THE FL PENINSULA. THE BOUNDARY SHOULD BE LOCATED SOMEWHERE
BETWEEN TAMPA AND CHIEFLAND BY SUNRISE ON TUESDAY. WILL HAVE TO PUT
A FEW SHOWERS IN THE FORECAST FROM TAMPA NORTHWARD IN PROXIMITY TO
THIS BOUNDARY...HOWEVER ANY RAINFALL DOES NOT LOOK TO BE A BIG
DEAL...WITH VERY LOW QPF. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH
LOWS IN THE 60S FOR ALL. BIGGER FORECAST CONCERN IS THE POTENTIAL
FOR SEA FOG DEVELOPMENT WHICH IS SHOWN BY MANY OF THE RELIABLE
GUIDANCE MEMBERS. LOW LEVEL FLOW WILL BE OUT OF THE SOUTHWEST AHEAD
OF THE FRONT TONIGHT...SO ANY SEA FOG THAT DOES DEVELOP WILL BE
ADVECTED ONSHORE. SEA FOG HAS GENERAL RULES WHICH HELP US DETERMINE
WHEN IT WILL DEVELOP BUT TRYING TO PREDICT EXACTLY WHERE/WHEN AND IT
EVOLUTION ONCE DEVELOPED IS VERY DIFFICULT. WILL HAVE FOG IN THE
FORECASTS EVENING AND OVERNIGHT SHIFT WILL SIMPLY NEED TO MONITOR
THE SITUATION WITH REGARDS TO ANY MARINE OR LAND BASED DENSE FOG
ADVISORIES.
TUESDAY...
COLD FRONT MAKES SLOW BUT STEADY PROGRESS SOUTHWARD THROUGH THE DAY
REACHING THE SOUTHERN FL PENINSULA TUESDAY EVENING. ANY SEA FOG WILL
STILL BE GOING TO BEGIN THE DAY...AND THE THREAT WILL NOT END UNTIL
THE PASSAGE OF THE COLD FRONT. A FEW SHOWERS WILL REMAIN IN THE
FORECAST...ALTHOUGH THE BEST CHANCES WILL SLIP TO THE SOUTHERN HALF
OF THE REGION BY THE AFTERNOON. DO NOT ANTICIPATE THAT TUESDAY WILL
BE CONSIDERED A "WET" DAY. ONCE AGAIN...ANY SHOWERS SHOULD BE BRIEF
AND QPF IS QUITE LOW. THERE REALLY IS NOT A WHOLE LOT OF COLD AIR
BEHIND THIS COLD FRONT. WE WILL SEE SOME DECREASE IN TEMPS INTO THE
MIDDLE OF THE WEEK...BUT MAINLY IT WILL GET DRIER AND MORE
COMFORTABLE FEELING. HOWEVER...DO NOT GET USED TO IT...AS ALL SIGNS
POINT TO A QUICK MODERATING TREND IN BOTH TEMPERATURES AND DEWPOINTS
AS HEAD TOWARD THE END OF THE WEEK.
&&
LONG TERM (WEDNESDAY THROUGH NEXT MONDAY)...
GFS AND ECMWF IN GOOD AGREEMENT WITH DIGGING A CLOSED LOW INTO NEW
MEXICO BY FRIDAY WITH A SOLID RIDGE OF HIGH PRESSURE OVER FLORIDA.
THE NEXT FRONT IS EXPECTED TO MOVE THROUGH SUNDAY NIGHT AND MONDAY.
THIS FRONT WILL BE SIMILAR TO THE TUESDAY FRONT WITH LIMITED RAIN AS
DYNAMICS REMAIN TO THE NORTH.
EXPECT ONLY A SLIGHT CHANCE OF SHOWERS TUESDAY NIGHT SOUTH OF
SEBRING TO PUNTA GORDA AS FRONT SLOWLY MOVES SOUTH OF FORECAST AREA.
MINOR IMPULSES ZIPPING ALONG ZONAL FLOW ALOFT HAS GFS/ECMWF WITH A
SMALL CHANCE OF RAIN IN SOUTHWEST FLORIDA WEDNESDAY. WILL LEAVE DRY
FOR NOW AS AREA IS BEHIND SURFACE FRONT AND ONLY EXPECT BATCHES OF
MID CLOUDS AND A FEW SPRINKLES.
WEDNESDAY WILL BE THE COOLEST DAY OF THE NEXT SEVEN DAYS...BUT WILL
STILL ABOUT 5 DEGREES ABOVE NORMAL. TEMPERATURES OF 10-15 DEGREES
ABOVE NORMAL EXPECTED THURSDAY THROUGH THE WEEKEND...ESPECIALLY ON
OVERNIGHT LOWS.
COLD FRONT MOVES SOUTH THROUGH AREA ON MONDAY WITH A SLIGHT CHANCE
OF RAIN SHOWERS. NO REAL COOL DOWN IN SIGHT.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS THE REGION THIS AFTERNOON AND
ANTICIPATE THESE CONDITIONS TO LAST INTO THE EVENING HOURS. AFTER
MIDNIGHT INTO TUESDAY MORNING THE POTENTIAL EXISTS FOR WIDESPREAD
VIS/CIG RESTRICTIONS. THE STATISTICAL AND DETERMINISTIC GUIDANCE ARE
ALL SUGGESTING FAVORABLE CONDITIONS FOR A COMBINATION OF LAND BASED
FOG DEVELOPMENT AND SEA FOG ADVECTING ONSHORE. SINCE A LOT OF THE
FORECAST IS CONDITIONAL ON THE DEVELOPMENT OF SEA FOG HAVE KEPT
THINGS IN THE MVFR CATEGORY JUST ABOVE IFR...HOWEVER THE POTENTIAL
EXISTS FOR MUCH MORE SIGNIFICANT RESTRICTIONS AFTER MIDNIGHT. THE
SITUATION WILL NEED TO BE MONITORED CLOSELY. IF WIDESPREAD
SIGNIFICANT RESTRICTIONS DO DEVELOP...THEY ARE LIKELY TO BE VERY
SLOW TO IMPROVE TUESDAY MORNING.
&&
.MARINE...
DENSE FOG WILL REMAIN POSSIBLE OVER THE WATERS LATER TONIGHT AS
WARM...HUMID AIR CONTINUES TO OVERRIDE THE COOLER GULF WATERS. A
WEAK FRONTAL BOUNDARY WILL APPROACH THE AREA LATE TONIGHT AND INTO
TUESDAY WITH A SLIGHT CHANCE OF SHOWERS POSSIBLE. THE WINDS WILL
SHIFT TO THE NORTH AND NORTHEAST IN THE WAKE OF THIS FRONT ON
TUESDAY...AND WILL REMAIN OUT OF THE NORTHEAST THROUGH THE REMAINDER
OF THE UPCOMING WEEK AS HIGH PRESSURE SETTLES INTO THE REGION.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS OTHER THAN FOG EXPECTED THE
NEXT SEVERAL DAYS. A WEAK COLD FRONT WILL CROSS THE REGION ON
TUESDAY WITH A FEW SHOWERS...AND THEN BE FOLLOWED BY A SLIGHTLY
DRIER AIRMASS FOR WEDNESDAY AND THURSDAY.
FOG POTENTIAL...AREAS OF FOG ARE EXPECTED TO DEVELOP OVER LAND AND
ALSO SEA FOG MOVING ASHORE OVERNIGHT AND TUESDAY MORNING. SOME OF
THE FOG IS EXPECTED TO BECOME DENSE. AREAS NEAR THE COAST THAT
EXPERIENCE SEA FOG MAY BE IN THE FOG FOR AN EXTENDED PERIOD OF TIME
FROM LATER TONIGHT INTO TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 67 75 62 74 / 10 30 0 10
FMY 66 79 65 79 / 0 20 20 20
GIF 65 78 61 74 / 0 30 10 10
SRQ 66 76 63 75 / 0 30 0 10
BKV 63 76 56 73 / 20 30 0 10
SPG 67 74 62 73 / 10 30 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/FIRE WEATHER...MROCZKA
LONG TERM...NOAH
MARINE...MCKAUGHAN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
325 PM CST MON DEC 29 2014
.SHORT TERM...
323 PM CST
REMAINDER OF THIS AFTERNOON AND TONIGHT...
LAKE EFFECT SNOW HAS LARGELY BEEN A NON-EVENT THIS AFTERNOON...
MAINLY DUE TO VERY DRY LOW LEVEL AIR IN PLACE OVER NERN
IL/NWRN...WITH DEWPOINTS IN THE UPPER TEENS IN SPITE OF THE NELY
FETCH OFF LAKE LAKE MICHIGAN WHERE WATER TEMPERATURES ARE STILL IN
THE MIDDLE TO UPPER 30S. THE MAIN IMPACT OF THE LAKE HAS BEEN A
BKN-OVC STRATOCU DECK MOVING OFF OF THE LAKE. HOWEVER...THERE HAS
BEEN SOME SCT LIGHT SNOW WITH THE COLD FRONT/LEADING EDGE OF THE
ARCTIC AIRMASS BUILDING ACROSS THE MISSISSIPPI VALLEY AND INTO THE
OHIO VALLEY. WHILE DEEP LAYER MOISTURE HAS BEEN MEAGER...THERE IS
JUST ENOUGH FORCING TO SQUEEZE OUT SOME ISOLD AREAS OF LIGHT
SNOW...MAINLY OVER PORTIONS OF THE AREA SOUTH OF I-80. FOR THE
OVERNIGHT HOURS...AS THE HIGH CONTINUES TO SPREAD SOUTH AND EAST
AND THE4 CENTER OF THE HIGH BUILDS INTO THE NRN PLAINS/NRN
ROCKIES...LOW LEVEL FLOW SHOULD GRADUALLY BACK THROUGH NLY TO
WNWLY. THE LONGER LAKE FETCH WHEN WINDS BECOME NLY COULD STILL
HELP BRING SOME LAKE EFFECT SNOW SHOWERS TO NWRN INDIANA...BUT
HAVE BACKED OFF ON QPF/SNOW AMOUNTS...WHILE MAINTAINING THE LIKELY
POPS...WITH THE IDEA OF A HIGH POP-LOW QPF SCENARIO. SO...STILL
THINK THERE COULD BE SOME ACCUMULATING LAKE EFFECT SNOW OVER
PORTIONS OF NWRN INDIANA NEAR THE LAKE...BUT AMOUNTS WILL LIKELY
BE LIGHT. AS THE ARCTIC AIRMASS CONTINUES TO SPREAD SOUTH AND
EAST...EXPECT LOWS TONIGHT TO DROP TO NEAR 10F OVER THE ROCKFORD
AREA...WHILE LOCATIONS EAST OF THE I-55 CORRIDOR SHOULD BE IN THE
UPPER TEENS TO LOWER 20S.
KREIN
&&
.LONG TERM...
323 PM CST
TUESDAY THROUGH MONDAY...
WHILE A COOLING TREND INITIATED BEGAN SUNDAY FOLLOWING THE PASSAGE
OF A COLD FRONT LATE SATURDAY...THE MORE SIGNIFICANT COOLING TREND
IS NOW UNDERWAY AS THE TRUE ARCTIC AIRMASS SPREADS ACROSS THE
REGION. AS OF 3PM CST MONDAY AFTERNOON...TEMPERATURES IN THE
NORTHERN PLAINS RANGED FROM THE SINGLE DIGITS ABOVE 0F TO THE SINGLE
DIGITS BELOW ZERO WITH DEWPOINTS OF -10 TO -15F. THE COLD AIR IS
STILL EXPECTED TO SPREAD ACROSS THE LOCAL AREA...BUT THE COLDEST AIR
SHOULD REMAIN TO THE WEST...OVER THE PLAINS AS THE CENTER OF THE
HIGH DROPS FROM THE NORTHERN ROCKIES TONIGHT TO THE LOWER
MISSISSIPPI VALLEY BY THURSDAY MORNING. CONDITIONS ACROSS THE AREA
SHOULD GENERALLY BE DRY THROUGH THURSDAY...WITH BELOW NORMAL
TEMPERATURES AND AMPLE SUNSHINE AS THE SFC HIGH PRESSURE BUILDS
ACROSS THE REGION. STILL ANTICIPATE THAT THE LOWEST TEMPERATURES
SHOULD BE TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE SFC RIDGE AXIS
BUILDS ACROSS THE AREA. WILL CARRY MIN TEMPS FOR WEDNESDAY MORNING
IN THE SINGLE DIGITS FOR THE ENTIRE CWA...RANGING FROM ARND 3F OVER
THE ROCKFORD AREA TO 8-9F EAST OF THE I-57 CORRIDOR. THERE IS SOME
CONCERN THAT THE TEMP FORECAST MAY BE A BIT TOO LOW...CONSIDERING
WINDS SHOULD REMAIN 5-10 MPH OVERNIGHT AND THERE IS NO SNOW COVER.
HOWEVER...EVEN THOUGH THE AIRMASS WILL BE VERY DRY AND SKIES SHOULD
BE MOSTLY CLEAR...EXPECT THAT THE LOWER TEMPERATURES WILL BE MORE
DRIVEN BY ADVECTION OF COLDER AIR FROM THE CENTRAL PLAINS...WITH THE
CENTER OF A 1050MB HIGH WILL BE CENTERED ALONG THE KANSAS COLORADO
BORDER...WITH A RIDGE AXIS EXTENDING TO THE EAST ACROSS CNTRL
ILLINOIS AND INTO THE UPPER OHIO VALLEY. WITH A DIGGING TROUGH
DROPPING THROUGH SCNTRL CANADA...A MODEST WLY GRADIENT WILL BE IN
PLACE...KEEPING WINDS FROM BECMG CALM. SO...EVEN THOUGH THERE IS NO
SNOW COVER OR CALM WINDS TO ALLOW FOR STRONG RADIATIVE COOLING TO
CAUSE THE TEMPERATURES TO DROP INTO THE SINGLE DIGITS...FEEL THAT
THERE WILL BE ENOUGH ADVECTION OF COLD AIR FROM THE CNTRL PLAINS TO
BRING THE LOW TEMPERATURES. THE MAIN IMPACT OF THIS COLD AIR AND
RELATIVELY BREEZY CONDITIONS WILL BE FOR WIND CHILL READINGS TO DROP
TO -5 TO -13 ACROSS THE CWA...WHICH WOULD THE COLDEST SINCE LATE
NOVEMBER.
THE OTHER FORECAST CONCERN FOR THE EXTENDED FORECAST PERIOD WILL BE
ASSOCIATED WITH A CLOSED LOW EXPECTED TO DROP INTO THE DESERT
SOUTHWEST WEDNESDAY AND WEDNESDAY NIGHT AS A STRONG PACIFIC
SHORTWAVE DROPS DOWN THE WEST COAST. THE MODELS HAVE BEEN VERY
CONSISTENT ON THE DEVELOPMENT OF THIS FEATURE...BUT THERE IS STILL A
VARIETY OF SOLUTIONS FROM THE VARIOUS MODELS IN THE TIMING OF
EJECTING THE SYSTEM OUT OF THE SRN ROCKIES AND TRACKING ACROSS THE
SOUTHERN PLAINS AND THEN LIFTING INTO THE OHIO VALLEY. THE GFS/GEM
REMAIN ON THE FASTER END OF THE FORECAST ENVELOPE WHILE THE ECMWF IS
THE CONSISTENTLY SLOWER SOLUTION. WHILE THE SLOWER SOLUTION IS
STILL FAVORED...CONFIDENCE IS STILL LOW THAT THE EVENTUAL
PROGRESSION OF THE SYSTEM COULD STILL BE SLOWER THAN WHAT THE ECMWF
CONTINUES TO INDICATE. SO...WILL MAINTAIN THE IDEA OF A SLOWER
SOLUTION. THE MAIN TREND FOR THE SENSIBLE WEATHER FEATURES SHOULD
BE A WARMING TREND WITH MAX TEMPS REBOUNDING INTO THE 30S FOR FRIDAY
AND SATURDAY AS UPPER HEIGHTS RISE IN ADVANCE OF THE UPPER LOW
EJECTING OUT OF THE DESERT SOUTHWEST. THERE IS DECENT CONFIDENCE IN
THIS GENERAL TREND. THERE IS ALSO DECENT CONFIDENCE IN THE IDEA OF
INCREASING POPS INTO THE WEEKEND...WHICH IS SLOW THAN PREVIOUSLY
FORECAST AND IN LINE WITH A SLOWER PROGRESSION OF THE SYSTEM.
HOWEVER THERE IS RELATIVELY LOW CONFIDENCE IN TIMING AND AMOUNT OF
PCPN AS THERE IS STILL THE CHANCE FOR SOME PHASING OF THE SRN STREAM
SYSTEM WITH NRN STREAM SHORT WAVE ENERGY DROPPING OUT OF THE NRN
PLAINS AND ACROSS THE GREAT LAKES. SO...WILL LIMIT POPS TO CHANCE
LEVELS FOR NOW WITH THE TREND TO DELAY THE ONSET OF ANY PCPN INTO
LATER IN THE FORECAST PERIOD.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PERIOD OF PATCHY MVFR CIGS 2000-3000 FT AGL THIS AFTERNOON.
* NORTH-NORTHEAST WINDS NEAR 12 KT THIS AFTERNOON. GRADUALLY
BECOMING NORTH-NORTHWEST LATER THIS EVENING AMD DECREASING
SLIGHTLY.
RATZER
//DISCUSSION...UPDATED 18Z...
TERMINALS REMAIN ALONG THE SOUTHEASTERN PERIPHERY OF A SPRAWLING
AREA OF HIGH PRESSURE OVER THE NORTHERN PLAINS AND UPPER MIDWEST.
COLDER AIR ON NORTHERLY WINDS WAS PRODUCING SOME MVFR STRATOCU OFF
THE LAKE FROM CHICAGO SOUTHEASTWARD...WHERE SURFACE WINDS WERE
MORE NORTH-NORTHEAST. WINDS WILL TURN MORE TO THE NORTH-NORTHWEST
LATER TONIGHT AS THE HIGH PRESSURE RIDGE SETTLES SOUTH. MVFR
CLOUDS WILL HANG IN LONGEST AT GYY WITH FLOW RIGHT OFF THE LAKE
AND THE POTENTIAL FOR SOME FLURRIES OR LIGHT LAKE-INDUCED SNOW
SHOWERS INTO TONIGHT. OTHERWISE...MDW MAY SEE A FEW FLURRIES WHILE
ORD/DPA AND RFD ARE NOT EXPECTED TO. SKIES SHOULD BECOME VFR
ACROSS THE AREA BY EVENING EXCEPT AT GYY...WHERE MVFR CONDITIONS
EXPECTED INTO TONIGHT.
NORTH-NORTHEAST WINDS AROUND 12 KT WILL BACK TO THE NORTH THIS
EVENING...AND TO THE NORTHWEST BY TUESDAY MORNING WITH SPEEDS
DECREASING SLIGHTLY FROM THIS AFTERNOONS 10+ KTS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH IN WINDS.
* MEDIUM IN TIMING OF DURATION MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
304 PM CST
NORTH TO NORTHWEST WINDS PERSIST ACROSS THE LAKE TONIGHT...THEN
GRADUALLY BACK SOUTHWEST BY WEDNESDAY AND INCREASE TO GALES BY
WEDNESDAY AFTERNOON OR EVENING. IT IS NOT CERTAIN HOW EFFECTIVELY
THESE SOMEWHAT MILDER SOUTHWEST WINDS WILL SUPPORT STRONG GALES
OVER THE COLD WATER...BUT GALES DO APPEAR LIKELY. UNTIL WINDS TURN
AWAY FROM NORTH AND NORTHWEST...CONDITIONS WILL BE FAVORABLE FOR
SMALL CRAFT HEADLINES FOR THE FIRST HALF OF THE WEEK...AND
ESPECIALLY IN THE INDIANA NEARSHORE WATERS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
315 PM CST Mon Dec 29 2014
.SHORT TERM...(Tonight)
ISSUED AT 315 PM CST MON DEC 29 2014
The 18Z surface analysis indicated the leading edge of the Arctic
airmass, ahead of an intense high pressure center in the Canadian
Rockies, was sinking just south of I-80. Clouds associated with cold
air undercutting were along the I-74 corridor at 20z/2 pm CST. This
area of cloudiness, along with low clouds in southern Iowa/northern
Missouri will overspread central and eventually southeast Illinois
this evening.
There should be enough weak forcing for snow flurries, particularly
in central Illinois this evening, and the rest of the forecast area
late tonight as the short range models point to weak lift just
behind the strongest low level cold advection. The HRRR model is
trying to produce some measurable snow from Bloomington to near
Taylorville between 6 pm and Midnight. At this point, it is the only
model, doing this and has most likely latched on to the area of
light snow around Pontiac. Will keep an eye on this, but for now
will stick to the mention of flurries.
The numerical guidance appears to be on the colder side due to less
cloud cover and stronger cold advection. Thus, will be going with
lows roughly 5 degrees warmer than guidance in central IL and 2-3
degrees warmer in southeast IL due to forecast cloud cover.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 315 PM CST MON DEC 29 2014
The narrow band of flurries will continue into Tuesday morning, but
should dissipate by afternoon. Behind this area, and strong 1050mb
high pressure area will drop into the region. This high will bring
dry weather to the area through Thur night, as well as well below
normal temps through the period. With the center of the high
dropping into the plains Tue night, the coldest temps are expected
to be Tue night through Wed. Northwesterly winds Tue night will
still be around 10mph, so there could be enough mixing to prevent
the bottom from dropping out on the temps. However, single digits
are still expected over half of the CWA, and combined with the wind
speeds, below zero wind chills are probably Tue night/Wed morning.
Beyond this, the high pressure will slide further south into the
southern plains by Thursday night. Temps may warm slightly, but only
to back around normal.
The return of slightly warmer temps and moisture will not occur
until the high pressure area move into the southeastern US Thur
night and Fri. However, along with this will come the chance of pcpn
to the area for the end of the week and the weekend. The questions
still remain as to the timing of the pcpn return, how warm it will
get, and what p-type will occur. Both the GFS and ECMWF continue to
not agree on the overall solution with this system. However, there
is some agreement as to how the upper level will evolve into
Saturday. The upper level low pressure area will weaken and get
lifted out into the flow over the weekend. ECMWF is much quicker
with this than the GFS. Models also agree that the pcpn will not
really begin until Fri night/Sat morning. However, there still
remains a chance of pcpn Friday in the southeast, so will keep
chance pops there, though would not be surprised to see this change
later. Beyond this, models do not agree with location of pcpn and
sfc low pressure area. With the ECMWF being quicker with the upper
level system, it keeps the low further south and therefore has very
little pcpn in our area...and only in the extreme southeast. The GFS
is further north with the low, but has shifted it east since
yesterday`s model runs. However, it keeps pcpn over the area through
the weekend, just not as much as before; and with the low east,
temps may not get as warm, thereby effecting the p-type through the
weekend. Will still be keeping the p-type simple and just going with
snow, becoming rain or snow, then snow at night and rain and/or snow
again during the daytime. The chance of pcpn will continue into Sat
night. Sunday and Monday will be dry for now as the system should be
well east of the area.
Temps in the extended will warm, with the warmest temps being on
Saturday and then cooling back off by Monday as another shot of
colder air slides into the area.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1158 AM CST MON DEC 29 2014
The leading edge of an Arctic boundary will gradually bring MVFR
ceilings into central Illinois this evening. However, in the
meantime, will be keeping an eye on low clouds advancing from the
northeast, due to NNE fetch off of Lake Michigan. For now it looks
like scattered cumulus can be expected at the TAF sites from KPIA
to KCMI this afternoon. However, there is a potential for a brief period
of MVFR ceilings this afternoon from KBMI to KCMI, but confidence
is low at this time.
As the Arctic airmass approaches this evening, MVFR ceilings
upstream will spread into central Illinois in the 00 to 03Z time
frame. There will be just enough low level forcing for periods of
light snow/flurries tonight. Many of the short range models are
indicating no accumulation with this light snow, however the NAM
is pointing to the development of very minor accumulations in east
central IL just before daybreak. For now, will only have the
ceilings at MVFR levels and keep visibility unrestricted, but will
need to watch this with future model runs and TAF issuances.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Miller
LONG TERM...Auten
AVIATION...Miller
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
154 PM CST MON DEC 29 2014
.SHORT TERM...
220 AM CST
THROUGH TUESDAY...
PRIMARY FORECAST CHALLENGE IN THE SHORT TERM IS WITH LAKE EFFECT
POTENTIAL THROUGH TONIGHT. DESPITE MODERATELY COLD AIR MASS IN PLACE
LAKE EFFECT THUS FAR TONIGHT HAS BEEN ABSENT AND THERMODYNAMICS ARE
NOT EXPECTED TO IMPROVE THIS MORNING SO PLAN TO JUST HOLD ON TO
SLIGHT CHANCE OF SNOW SHOWERS AND CHANCE OF FLURRIES ALONG THE
ILLINOIS LAKE SHORE THIS MORNING. BEST HOPE OF LAKE EFFECT SNOW
SHOWERS/FLURRIES THIS MORNING WILL HINGE ON MID LEVEL CLOUDINESS
BEGINNING TO SPREAD IN ACTUALLY SEEDING THE LAKE STRATOCUMULUS.
LOW LEVEL FLOW WILL GRADUALLY BACK TO NORTH THIS AFTERNOON THEN
NORTH-NORTHWEST WITH THE RESULTANT LAKE EFFECT POTENTIAL PIVOTING
AROUND THE SOUTH RIM OF LAKE MICHIGAN THROUGH TONIGHT.
THERMODYNAMICS COULD IMPROVE SLIGHTLY THIS AFTERNOON...THOUGH
GETTING INTO A DIURNALLY UNFAVORABLE TIME OF DAY CONSIDERING THE
STILL MARGINAL SET UP FOR LAKE EFFECT SNOW TO GET CRANKING THIS
AFTERNOON. PLAN TO JUST GRADUALLY SHIFT FLURRIES/SMALL SNOW SHOWERS
CHANCES EAST FOCUSING MORE INTO NW INDY AND EXTREME SE COOK THIS
AFTERNOON.
MORE FAVORABLE THERMODYNAMIC ENVIRONMENT WILL DEVELOP THIS EVENING
AND CONTINUE OVERNIGHT WITH IMPROVED INSTABILITY AND SLIGHTLY HIGHER
INVERSION HEIGHTS. WILL MAINTAIN HIGH CHANCE/LOW END LIKELY POPS
NEAR THE LAKE TONIGHT BUT ACCUMULATIONS WILL PROBABLY BE PRETTY
MINOR BECAUSE AS THERMAL INSTABILITY INCREASES...MODELS ALSO PROG
INCREASINGLY DRY AIR TO SPREAD IN JUST ABOVE THE BOUNDARY LAYER
INVERSION WHICH GIVEN THE MARGINAL TEMPS IN THE CLOUD BARING LAYER
REALLY DOES NOT BODE WELL FOR EFFICIENTLY ACCUMULATING SNOW. CURRENT
THINKING IS NO ACCUMULATION IN NE IL AND MOSTLY LESS THAN AN INCH IN
NW INDY TONIGHT...THOUGH ISOLATED AMOUNTS OF 1 TO POSSIBLY UP TO 2
INCHES WOULD BE ON THE HIGH SIDE. LAKE EFFECT THREAT WILL SHIFT EAST
OUT OF THE CWA TUESDAY AND SHOULD SEE CLOUDS CLEAR OUT AND SKIES
BECOME SUNNY...BUT THE SUNSHINE WILL BE MORE FOR SHOW THAN ANYTHING
ELSE AS TEMPS STRUGGLE TO REACH 20F.
IZZI
&&
.LONG TERM...
220 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
COLD AIR MASS WILL REMAIN ENTRENCHED WEDNESDAY BUT MAGNITUDE OF THE
COLD WILL NO DOUBT BE TEMPERED BY THE LACK OF SNOW COVER HERE OR
EVEN FAR UPSTREAM...SO WHILE IT WILL BE COLD HAVE GONE WITH TEMPS A
BIT ABOVE WHAT 850MB/925MB CLIMO WOULD SUPPORT. WARM ADVECTION
BEGINS WEDNESDAY NIGHT AND REALLY CRANKS INTO GEAR THURSDAY ALLOWING
FOR A NICE REBOUND IN TEMPS...THOUGH THE WARMING WILL BE MORE
ACADEMIC THAN ACTUALLY FELT AS GUSTY SOUTHWEST WINDS PRODUCE STILL
CHILLY WIND CHILLS THURSDAY. TEMPS SHOULD CONTINUE TO MODERATE ON
FRIDAY WITH PRECIPITATION LOOKING PRETTY UNLIKELY FRIDAY.
STRONG TROUGH WILL TO DIG INTO THE DESERT SOUTHWEST NEW YEARS EVE
AND IS FORECAST TO PRODUCE ACCUMULATING SNOW ON THE LAS VEGAS STRIP
NEW YEARS EVE WHERE WINTER STORM WATCHES ARE IN EFFECT! THIS
POWERFUL SYSTEM IS PROGGED TO CLOSE OFF A LARGE DEEP CIRCULATION
THAT BECOMES CUT OFF FROM THE WESTERLIES. A SET UP LIKE THIS MORE
OFTEN THAN NOT SPELLS BIG TROUBLES FOR PREDICTABILITY IN THE MEDIUM
RANGE AS THIS SYSTEM WILL PRESENT A COUPLE OF THE THINGS THAT MODELS
STRUGGLE WITH...FIRST HANDLING TRACK/TIMING OF EJECTING SOUTHWEST
CUT OFFS AND SECOND THE POTENTIAL FOR PHASING WITH NORTHERN STREAM
SHORTWAVE ENERGY.
THE RANGE OF POSSIBILITIES FOR THE WEEKEND IN OUR AREA TRULY RUN THE
GAMUT FROM DRY CONDITIONS ALL WEEKEND TO RAIN...ACCUMULATING
SNOW...A WINTRY MIX...OR SOME COMBINATION OF THE ABOVE. THE
OPERATIONAL GFS IS MOST GUNG-HO WITH PHASING AND FASTEST EJECTING
THE LOW EASTWARD...WHICH WOULD SEEM TO COUNTER WHAT IS TYPICAL IN
THESE SCENARIOS. THE PARALLEL GFS AND ECMWF ARE BOTH SOUTH AND
SLOWER WITH THE SYSTEM AND WOULD LEAD TO A DRY WEEKEND IN OUR AREA.
THE BLENDED MODEL POPS FOR THE WEEKEND HAVE COME DOWN FROM PREVIOUS
CYCLES AND AM NOT PLANNING ANY CHANGES TO THEM AS PREDICTABILITY IS
JUST TOO LOW AT THIS POINT. AT THIS POINT THE CHANCES OF THE LAS
VEGAS STRIP SEEING MORE ACCUMULATING SNOW THE NEXT 7 DAYS IS
CURRENTLY HIGHER THAN HERE IN OUR CWA...QUITE ATYPICAL AND
DEFINITELY NOT SOMETHING THAT ONE WOULD TYPICALLY WAGER WOULD BE
THE CASE!
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PERIOD OF PATCHY MVFR CIGS 2000-3000 FT AGL THIS AFTERNOON.
* NORTH-NORTHEAST WINDS NEAR 12 KT THIS AFTERNOON. GRADUALLY
BECOMING NORTH-NORTHWEST LATER THIS EVENING AMD DECREASING
SLIGHTLY.
RATZER
//DISCUSSION...UPDATED 18Z...
TERMINALS REMAIN ALONG THE SOUTHEASTERN PERIPHERY OF A SPRAWLING
AREA OF HIGH PRESSURE OVER THE NORTHERN PLAINS AND UPPER MIDWEST.
COLDER AIR ON NORTHERLY WINDS WAS PRODUCING SOME MVFR STRATOCU OFF
THE LAKE FROM CHICAGO SOUTHEASTWARD...WHERE SURFACE WINDS WERE
MORE NORTH-NORTHEAST. WINDS WILL TURN MORE TO THE NORTH-NORTHWEST
LATER TONIGHT AS THE HIGH PRESSURE RIDGE SETTLES SOUTH. MVFR
CLOUDS WILL HANG IN LONGEST AT GYY WITH FLOW RIGHT OFF THE LAKE
AND THE POTENTIAL FOR SOME FLURRIES OR LIGHT LAKE-INDUCED SNOW
SHOWERS INTO TONIGHT. OTHERWISE...MDW MAY SEE A FEW FLURRIES WHILE
ORD/DPA AND RFD ARE NOT EXPECTED TO. SKIES SHOULD BECOME VFR
ACROSS THE AREA BY EVENING EXCEPT AT GYY...WHERE MVFR CONDITIONS
EXPECTED INTO TONIGHT.
NORTH-NORTHEAST WINDS AROUND 12 KT WILL BACK TO THE NORTH THIS
EVENING...AND TO THE NORTHWEST BY TUESDAY MORNING WITH SPEEDS
DECREASING SLIGHTLY FROM THIS AFTERNOONS 10+ KTS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH IN WINDS.
* MEDIUM IN TIMING OF DURATION MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
247 AM CST
A COLD FRONT WILL CLEAR THE SOUTH END OF THE LAKE LATER THIS MORNING
AS STRONG HIGH PRESSURE IN NORTHWEST CANADA BEGINS TO BUILD SOUTH
INTO THE CENTRAL PLAINS. AS THE HIGH CONTINUES TO SLIDE INTO THE
PLAINS...LOW PRESSURE WILL TRACK SOUTHEAST THROUGH HUDSON BAY.
EXPECT A DECENT GRADIENT TO SETUP BETWEEN THESE TWO STRONG FEATURES.
THIS WILL CREATE A PERIOD OF GALES OVER THE LAKE WEDNESDAY AND
WEDNESDAY EVENING. THE HIGH WILL THEN SHIFT INTO THE TENNESSEE
VALLEY AND WEAKEN WHILE THE HUDSON BAY LOW RETREATS INTO THE
CANADIAN MARTIMES ON FRIDAY.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1159 AM CST Mon Dec 29 2014
.UPDATE...
ISSUED AT 1042 AM CST MON DEC 29 2014
No major changes made to the forecast late this morning, just
tweaked the high temperatures down a few degrees for today,
particularly in southeast Illinois.
Still looking for a gradual increase in cloudiness, especially
along and west of the Illinois River Valley this afternoon. The
latest satellite loop indicated the leading edge of Arctic air and
lower clouds/flurries just moving into northwest IL, extending
west-southwest toward extreme northern Missouri. The HRRR and to a
certain extent the RAP are a bit too quick with the advancement of
the clouds into central IL, so will stick with the gradual
increase.
Despite plenty of sunshine, temperatures are climbing a bit slower
than previously thought. Thus, shaved high temperatures a few
degrees, with mid 30s anticipated across central and eastern IL
with upper 30s south of I-70.
Will maintain the mention of flurries for tonight across the
forecast area, but a preliminary look at the updated models are
indicating they may be confined to areas in west central and
central IL.
&&
.SHORT TERM...(This afternoon through tonight)
ISSUED AT 1147 AM CST MON DEC 29 2014
08z/2am surface analysis shows strong 1057mb high over northern
British Columbia/Alberta. Bitterly cold airmass beneath the high
with current temps in the teens and 20s below zero is building
southward into the Northern Plains/Upper Midwest, with the leading
edge of the colder air sinking toward northern Illinois. Front will
remain north of the KILX CWA today: however, increasing mid/high
clouds in the vicinity of the boundary will be noted across the
north. End result will be partly to mostly cloudy skies north of
Peoria, with mostly sunny skies further south across the remainder
of the area. High temperatures will once again be near normal for
this time of year in the middle to upper 30s.
&&
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 1147 AM CST MON DEC 29 2014
Main weather story this week will be the shot of very cold air
expected Tuesday through Thursday. Arctic cold front will settle
southward into central Illinois tonight, accompanied by clouds and
perhaps a few flurries. NAM time-height cross-sections show much
shallower moisture profiles and weaker lift than they did on
previous runs: however, think strong CAA will be enough to produce
scattered flurries overnight. Any flurries will come to an end
Tuesday morning as high pressure builds into the region and skies
gradually clear. High temperatures will be much colder than today,
ranging from the lower 20s northwest to the lower 30s south of
I-70. Heart of the coldest airmass will arrive Tuesday night into
Wednesday. Thanks to clear skies and diminishing winds, low
temperatures Tuesday night will bottom out in the single digits and
teens, with corresponding wind-chill readings dropping below zero.
Despite full sunshine, highs on Wednesday will struggle to reach the
lower to middle 20s. As high pressure sinks south of the region,
winds will back to the southwest and help boost temps back into the
lower 30s by Thursday.
Forecast becomes more complicated later in the week, as a southern
stream system slowly approaches from the southwest. Model-to-model
as well as run-to-run consistency remains poor, so forecast
confidence beyond Thursday is low. Latest trend observed with the
00z Dec 29 model suite suggests a deeper cut-off low over the Desert
Southwest and thus a slower northeastward ejection. Current water
vapor imagery shows a strong jet streak diving southward along the
west coast of the US, which is progged to carve out a closed upper
low over California within the next 48 hours. Models are in very
good agreement initially, showing the low meandering slowly eastward
to the Texas/Oklahoma panhandles by Saturday evening: however, they
have very different ideas on how to handle precip ahead of the
system. The ECMWF shows precip breaking out well in advance of the
low across the southern Plains Thursday, then spreading
northeastward into south-central Illinois and the Ohio River Valley
late Thursday night into Friday. Given presence of cold/dry airmass
across the region, am very skeptical about this aggressive push of
precip. As a result, will continue with a dry forecast Thursday
night and will reduce PoPs significantly during the day Friday. The
GFS seems to have a much more realistic solution, showing precip
remaining south of Illinois until Friday night into Saturday.
Models are in poor agreement with what happens to the southwest
system over the weekend, with the ECMWF maintaining a closed 500mb
low longer than the GFS, which opens the wave and allows it to be
absorbed into the northern stream much faster. If the ECMWF
verifies, much of the precip associated with the low will remain
southeast of Illinois across the Ohio River Valley. This is a
drastic change from its previous runs, so am looking at this with a
great deal of skepticism. Prefer the more consistent GFS, which
opens the low and brings it northward into the area on Saturday. As
a result, have introduced chance PoPs across the board Friday
night/Saturday, then have ended precip chances by Sunday as the
system exits into the Great Lakes. Precip type will be an issue as
well, with forecast soundings and surface temps initially supporting
snow or a rain/snow mix. Atmosphere will likely warm enough to
change the precip to mostly rain on Saturday before colder air
returns Saturday night into Sunday. Overall this does not like a
major winter storm for central Illinois, but future model runs will
need to be monitored for any potential changes.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1158 AM CST MON DEC 29 2014
The leading edge of an Arctic boundary will gradually bring MVFR
ceilings into central Illinois this evening. However, in the
meantime, will be keeping an eye on low clouds advancing from the
northeast, due to NNE fetch off of Lake Michigan. For now it looks
like scattered cumulus can be expected at the TAF sites from KPIA
to KCMI this afternoon. However, there is a potential for a brief period
of MVFR ceilings this afternoon from KBMI to KCMI, but confidence
is low at this time.
As the Arctic airmass approaches this evening, MVFR ceilings
upstream will spread into central Illinois in the 00 to 03Z time
frame. There will be just enough low level forcing for periods of
light snow/flurries tonight. Many of the short range models are
indicating no accumulation with this light snow, however the NAM
is pointing to the development of very minor accumulations in east
central IL just before daybreak. For now, will only have the
ceilings at MVFR levels and keep visibility unrestricted, but will
need to watch this with future model runs and TAF issuances.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Miller
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Miller
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1133 AM CST MON DEC 29 2014
.SHORT TERM...
220 AM CST
THROUGH TUESDAY...
PRIMARY FORECAST CHALLENGE IN THE SHORT TERM IS WITH LAKE EFFECT
POTENTIAL THROUGH TONIGHT. DESPITE MODERATELY COLD AIR MASS IN PLACE
LAKE EFFECT THUS FAR TONIGHT HAS BEEN ABSENT AND THERMODYNAMICS ARE
NOT EXPECTED TO IMPROVE THIS MORNING SO PLAN TO JUST HOLD ON TO
SLIGHT CHANCE OF SNOW SHOWERS AND CHANCE OF FLURRIES ALONG THE
ILLINOIS LAKE SHORE THIS MORNING. BEST HOPE OF LAKE EFFECT SNOW
SHOWERS/FLURRIES THIS MORNING WILL HINGE ON MID LEVEL CLOUDINESS
BEGINNING TO SPREAD IN ACTUALLY SEEDING THE LAKE STRATOCUMULUS.
LOW LEVEL FLOW WILL GRADUALLY BACK TO NORTH THIS AFTERNOON THEN
NORTH-NORTHWEST WITH THE RESULTANT LAKE EFFECT POTENTIAL PIVOTING
AROUND THE SOUTH RIM OF LAKE MICHIGAN THROUGH TONIGHT.
THERMODYNAMICS COULD IMPROVE SLIGHTLY THIS AFTERNOON...THOUGH
GETTING INTO A DIURNALLY UNFAVORABLE TIME OF DAY CONSIDERING THE
STILL MARGINAL SET UP FOR LAKE EFFECT SNOW TO GET CRANKING THIS
AFTERNOON. PLAN TO JUST GRADUALLY SHIFT FLURRIES/SMALL SNOW SHOWERS
CHANCES EAST FOCUSING MORE INTO NW INDY AND EXTREME SE COOK THIS
AFTERNOON.
MORE FAVORABLE THERMODYNAMIC ENVIRONMENT WILL DEVELOP THIS EVENING
AND CONTINUE OVERNIGHT WITH IMPROVED INSTABILITY AND SLIGHTLY HIGHER
INVERSION HEIGHTS. WILL MAINTAIN HIGH CHANCE/LOW END LIKELY POPS
NEAR THE LAKE TONIGHT BUT ACCUMULATIONS WILL PROBABLY BE PRETTY
MINOR BECAUSE AS THERMAL INSTABILITY INCREASES...MODELS ALSO PROG
INCREASINGLY DRY AIR TO SPREAD IN JUST ABOVE THE BOUNDARY LAYER
INVERSION WHICH GIVEN THE MARGINAL TEMPS IN THE CLOUD BARING LAYER
REALLY DOES NOT BODE WELL FOR EFFICIENTLY ACCUMULATING SNOW. CURRENT
THINKING IS NO ACCUMULATION IN NE IL AND MOSTLY LESS THAN AN INCH IN
NW INDY TONIGHT...THOUGH ISOLATED AMOUNTS OF 1 TO POSSIBLY UP TO 2
INCHES WOULD BE ON THE HIGH SIDE. LAKE EFFECT THREAT WILL SHIFT EAST
OUT OF THE CWA TUESDAY AND SHOULD SEE CLOUDS CLEAR OUT AND SKIES
BECOME SUNNY...BUT THE SUNSHINE WILL BE MORE FOR SHOW THAN ANYTHING
ELSE AS TEMPS STRUGGLE TO REACH 20F.
IZZI
&&
.LONG TERM...
220 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
COLD AIR MASS WILL REMAIN ENTRENCHED WEDNESDAY BUT MAGNITUDE OF THE
COLD WILL NO DOUBT BE TEMPERED BY THE LACK OF SNOW COVER HERE OR
EVEN FAR UPSTREAM...SO WHILE IT WILL BE COLD HAVE GONE WITH TEMPS A
BIT ABOVE WHAT 850MB/925MB CLIMO WOULD SUPPORT. WARM ADVECTION
BEGINS WEDNESDAY NIGHT AND REALLY CRANKS INTO GEAR THURSDAY ALLOWING
FOR A NICE REBOUND IN TEMPS...THOUGH THE WARMING WILL BE MORE
ACADEMIC THAN ACTUALLY FELT AS GUSTY SOUTHWEST WINDS PRODUCE STILL
CHILLY WIND CHILLS THURSDAY. TEMPS SHOULD CONTINUE TO MODERATE ON
FRIDAY WITH PRECIPITATION LOOKING PRETTY UNLIKELY FRIDAY.
STRONG TROUGH WILL TO DIG INTO THE DESERT SOUTHWEST NEW YEARS EVE
AND IS FORECAST TO PRODUCE ACCUMULATING SNOW ON THE LAS VEGAS STRIP
NEW YEARS EVE WHERE WINTER STORM WATCHES ARE IN EFFECT! THIS
POWERFUL SYSTEM IS PROGGED TO CLOSE OFF A LARGE DEEP CIRCULATION
THAT BECOMES CUT OFF FROM THE WESTERLIES. A SET UP LIKE THIS MORE
OFTEN THAN NOT SPELLS BIG TROUBLES FOR PREDICTABILITY IN THE MEDIUM
RANGE AS THIS SYSTEM WILL PRESENT A COUPLE OF THE THINGS THAT MODELS
STRUGGLE WITH...FIRST HANDLING TRACK/TIMING OF EJECTING SOUTHWEST
CUT OFFS AND SECOND THE POTENTIAL FOR PHASING WITH NORTHERN STREAM
SHORTWAVE ENERGY.
THE RANGE OF POSSIBILITIES FOR THE WEEKEND IN OUR AREA TRULY RUN THE
GAMUT FROM DRY CONDITIONS ALL WEEKEND TO RAIN...ACCUMULATING
SNOW...A WINTRY MIX...OR SOME COMBINATION OF THE ABOVE. THE
OPERATIONAL GFS IS MOST GUNG-HO WITH PHASING AND FASTEST EJECTING
THE LOW EASTWARD...WHICH WOULD SEEM TO COUNTER WHAT IS TYPICAL IN
THESE SCENARIOS. THE PARALLEL GFS AND ECMWF ARE BOTH SOUTH AND
SLOWER WITH THE SYSTEM AND WOULD LEAD TO A DRY WEEKEND IN OUR AREA.
THE BLENDED MODEL POPS FOR THE WEEKEND HAVE COME DOWN FROM PREVIOUS
CYCLES AND AM NOT PLANNING ANY CHANGES TO THEM AS PREDICTABILITY IS
JUST TOO LOW AT THIS POINT. AT THIS POINT THE CHANCES OF THE LAS
VEGAS STRIP SEEING MORE ACCUMULATING SNOW THE NEXT 7 DAYS IS
CURRENTLY HIGHER THAN HERE IN OUR CWA...QUITE ATYPICAL AND
DEFINITELY NOT SOMETHING THAT ONE WOULD TYPICALLY WAGER WOULD BE
THE CASE!
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* PERIOD OF PATCHY MVFR CIGS 2000-3000 FT AGL THIS AFTERNOON.
* A FEW FLURRIES POSSIBLE ESPECIALLY AT MDW...THOUGH NOT EXPECTED
TO RESTRICT VSBY OR ACCUMULATE.
* NORTH-NORTHEAST WINDS NEAR 12 KT THIS AFTERNOON. GRADUALLY
BECOMING NORTH-NORTHWEST LATER THIS EVENING AMD DECREASING
SLIGHTLY.
RATZER
//DISCUSSION...UPDATED 18Z...
TERMINALS REMAIN ALONG THE SOUTHEASTERN PERIPHERY OF A SPRAWLING
AREA OF HIGH PRESSURE OVER THE NORTHERN PLAINS AND UPPER MIDWEST.
COLDER AIR ON NORTHERLY WINDS WAS PRODUCING SOME MVFR STRATOCU OFF
THE LAKE FROM CHICAGO SOUTHEASTWARD...WHERE SURFACE WINDS WERE
MORE NORTH-NORTHEAST. WINDS WILL TURN MORE TO THE NORTH-NORTHWEST
LATER TONIGHT AS THE HIGH PRESSURE RIDGE SETTLES SOUTH. MVFR
CLOUDS WILL HANG IN LONGEST AT GYY WITH FLOW RIGHT OFF THE LAKE
AND THE POTENTIAL FOR SOME FLURRIES OR LIGHT LAKE-INDUCED SNOW
SHOWERS INTO TONIGHT. OTHERWISE...MDW MAY SEE A FEW FLURRIES WHILE
ORD/DPA AND RFD ARE NOT EXPECTED TO. SKIES SHOULD BECOME VFR
ACROSS THE AREA BY EVENING EXCEPT AT GYY...WHERE MVFR CONDITIONS
EXPECTED INTO TONIGHT.
NORTH-NORTHEAST WINDS AROUND 12 KT WILL BACK TO THE NORTH THIS
EVENING...AND TO THE NORTHWEST BY TUESDAY MORNING WITH SPEEDS
DECREASING SLIGHTLY FROM THIS AFTERNOONS 10+ KTS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH IN WINDS.
* MEDIUM IN TIMING OF DURATION MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
247 AM CST
A COLD FRONT WILL CLEAR THE SOUTH END OF THE LAKE LATER THIS MORNING
AS STRONG HIGH PRESSURE IN NORTHWEST CANADA BEGINS TO BUILD SOUTH
INTO THE CENTRAL PLAINS. AS THE HIGH CONTINUES TO SLIDE INTO THE
PLAINS...LOW PRESSURE WILL TRACK SOUTHEAST THROUGH HUDSON BAY.
EXPECT A DECENT GRADIENT TO SETUP BETWEEN THESE TWO STRONG FEATURES.
THIS WILL CREATE A PERIOD OF GALES OVER THE LAKE WEDNESDAY AND
WEDNESDAY EVENING. THE HIGH WILL THEN SHIFT INTO THE TENNESSEE
VALLEY AND WEAKEN WHILE THE HUDSON BAY LOW RETREATS INTO THE
CANADIAN MARTIMES ON FRIDAY.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1043 AM CST Mon Dec 29 2014
.SHORT TERM...(This afternoon through tonight)
ISSUED AT 1042 AM CST MON DEC 29 2014
No major changes made to the forecast late this morning, just
tweaked the high temperatures down a few degrees for today,
particularly in southeast Illinois.
Still looking for a gradual increase in cloudiness, especially
along and west of the Illinois River Valley this afternoon. The
latest satellite loop indicated the leading edge of Arctic air and
lower clouds/flurries just moving into northwest IL, extending
west-southwest toward extreme northern Missouri. The HRRR and to a
certain extent the RAP are a bit too quick with the advancement of
the clouds into central IL, so will stick with the gradual
increase.
Despite plenty of sunshine, temperatures are climbing a bit slower
than previously thought. Thus, shaved high temperatures a few
degrees, with mid 30s anticipated across central and eastern IL
with upper 30s south of I-70.
Will maintain the mention of flurries for tonight across the
forecast area, but a preliminary look at the updated models are
indicating they may be confined to areas in west central and
central IL.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 308 AM CST MON DEC 29 2014
Main weather story this week will be the shot of very cold air
expected Tuesday through Thursday. Arctic cold front will settle
southward into central Illinois tonight, accompanied by clouds and
perhaps a few flurries. NAM time-height cross-sections show much
shallower moisture profiles and weaker lift than they did on
previous runs: however, think strong CAA will still be enough to
produce scattered flurries overnight. Any flurries will come to
an end Tuesday morning as high pressure builds into the region and
skies gradually clear. High temperatures will be much colder than
today, ranging from the lower 20s northwest to the lower 30s south
of I-70. Heart of the coldest airmass will arrive Tuesday night
into Wednesday. Thanks to clear skies and diminishing winds, low
temperatures Tuesday night will bottom out in the single digits
and teens, with corresponding wind-chill readings dropping below
zero. Despite full sunshine, highs on Wednesday will struggle to
reach the lower to middle 20s. As high pressure sinks south of
the region, winds will back to the southwest and help boost temps
back into the lower 30s by Thursday.
Forecast becomes more complicated later in the week, as a southern
stream system slowly approaches from the southwest. Model-to-model
as well as run-to-run consistency remains poor, so forecast
confidence beyond Thursday is low. Latest trend observed with the
00z Dec 29 model suite suggests a deeper cut-off low over the Desert
Southwest and thus a slower northeastward ejection. Current water
vapor imagery shows a strong jet streak diving southward along the
West Coast, which is progged to carve out a closed upper low over
California within the next 48 hours. Models are in very good
agreement initially, showing the low meandering slowly eastward to
the Texas/Oklahoma panhandles by Saturday evening: however, they
have very different ideas on how to handle precip ahead of the
system. The ECMWF shows precip breaking out well in advance of
the low across the southern Plains Thursday, then spreading
northeastward into south-central Illinois and the Ohio River
Valley late Thursday night into Friday. Given presence of
cold/dry airmass across the region, am very skeptical about this
aggressive push of precip. As a result, will continue with a dry
forecast Thursday night and will reduce PoPs significantly during
the day Friday. The GFS seems to have a much more realistic
solution, showing precip remaining south of Illinois until Friday
night into Saturday. Models are in poor agreement with what
happens to the southwest system over the weekend, with the ECMWF
maintaining a closed 500mb low longer than the GFS, which opens
the wave and allows it to be absorbed into the northern stream
much faster. If the ECMWF verifies, much of the precip associated
with the low will remain southeast of Illinois across the Ohio
River Valley. This is a drastic change from its previous runs, so
am looking at this with a great deal of skepticism. Prefer the
more consistent GFS, which opens the low and brings it northward
into the area on Saturday. As a result, have introduced chance
PoPs across the board Friday night/Saturday, then have ended
precip chances by Sunday as the system exits into the Great Lakes.
Precip type will be an issue as well, with forecast soundings and
surface temps initially supporting snow or a rain/snow mix.
Atmosphere will likely warm enough to change the precip to mostly
rain on Saturday before colder air returns Saturday night into
Sunday. Overall this does not look like a major winter storm for
central Illinois, but future model runs will need to be monitored
for any potential changes.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 546 AM CST MON DEC 29 2014
An arctic cold will slip south of the central Illinois terminals
today. VFR conditions for much of today will eventually fall to
MVFR this evening as an area of low level moisture spills in from
the north along with the colder air. A few flurries are possible
as the low clouds return, but no significant snow is anticipated.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Miller
LONG TERM...Barnes
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS JACKSON KY
131 PM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 130 PM EST MON DEC 29 2014
CLOUD COVER HOLDING OVER THE AREA THIS AFTERNOON HAS REALLY IMPACTED
TEMPERATURES. STILL HAD TO LOWER MAX TEMPS A FEW DEGREES ACROSS THE
AREA. WILL CONTINUE TO KEEP CLOUD COVER OVER THE AREA INTO TONIGHT
BUT WILL BRING SOME CLEARING INTO THE NORTHWEST. THIS IN
MIND...PRECIP HAS WANED A BIT IN THE EAST AND SHORT TERM MODELS HINT
AT RAIN TONIGHT BEING MORE CONFINED TO THE EAST DUE TO THE LOW
FINALLY BEGINNING TO PUSH EAST. HOWEVER...SOME LINGERING RAIN ALONG
THE HIGHER TERRAIN WILL BEGIN TO MIX WITH AND CHANGE TO ALL SNOW LATE
TONIGHT. THOUGH ACCUMULATION IS NOT EXPECTED. OTHERWISE...THE MAIN
CHANGE TO THIS UPDATE WAS TO TAKE PATCHY FOG OUT OF THE FORECAST. A
NEW ZFP HAS BEEN ISSUED WITH THIS UPDATE.
UPDATE ISSUED AT 1041 AM EST MON DEC 29 2014
A MOIST LOWER PORTION OF THE ATMOSPHERE COUPLED WITH A SLOWLY EXITING
LOW PRESSURE SYSTEM ON THE LEE SIDE OF THE APPALACHIANS HAS AND WILL
RESULT IN LINGERING CLOUD COVER OVER EASTERN KENTUCKY. IN FACT...WEAK
N TO NNE FLOW INTO THE AREA IS BARELY ERODING ANY CLOUD COVER OVER IN
CENTRAL OH AND IN. WILL EXPECT CLOUD COVER TO LINGER THROUGH TODAY
AND INTO TONIGHT...AT LEAST INTO EASTERN KENTUCKY. THE NORTHERN AND
WESTERN BLUEGRASS AREAS WILL EVENTUALLY BEGIN TO CLEAR OUT
TONIGHT...EVEN INTO FLEMING...BATH AND ROWAN COUNTIES. WITH THIS IN
MIND...HAVE UPDATED THE FORECAST TO LOWER MAX TEMPS FOR TODAY AS
CLOUD COVER WILL KEEP ANY HEATING FROM REACHING THE
SURFACE...ESPECIALLY IN A NORTHERLY FLOW. SOME LINGERING DRIZZLE AND
LIGHT RAIN STILL REMAIN IN THE EAST THIS MORNING AND MAY LINGER INTO
THE AFTERNOON BANKED AGAINST THE HIGHER TERRAIN IN THE EAST. STILL
ONLY A SLIGHT CHANCE IS WORTH MENTIONING. THE FOG WAS LEFT IN THE
FORECAST AS SOME OBSERVATIONS WERE STILL SHOWING SOME GROUND TRUTH OF
THIS. THE FOG MAY LINGER THROUGHOUT THE ENTIRE DAY WITH THE MOIST
BOUNDARY LAYER AND DRIZZLE PRESENT. WILL VISIT THIS AGAIN AROUND THE
NOON TIME PERIOD. A NEW ZFP HAS BEEN SENT OUT TO ADDRESS THESE
CHANGES.
UPDATE ISSUED AT 640 AM EST MON DEC 29 2014
WSR-88D RADAR CONTINUES TO INDICATE SOME LIGHT RAIN AND DRIZZLE THIS
MORNING WITH BEST RETURNS ACROSS THE FAR SE PORTIONS OF THE CWA. ALSO
WITH LOW LEVEL MOISTURE IN PLACE THERE WILL BE PATCHY FOG IN SPOTS
WITH MANY METAR SITES COMING IN WITH ANYWHERE FROM HALF A MILE TO TWO
AND A HALF MILE VIS THIS MORNING. SO DID UPDATE WITH SOME DRIZZLE AND
PATCHY FOG. ALSO FRESHENED UP TEMPS/DEWPOINTS/WIND WITH LATEST OBS
AND TRENDS. NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 130 PM EST MON DEC 29 2014
MOSTLY ALL THE DRIZZLE AND LIGHT RAIN IS COMING TO AN END ACROSS
EASTERN KENTUCKY WITH THEN EXCEPTION OF THE FAR EAST. THE EXTENSIVE
CLOUD COVER IS THOUGH...EXPECTED TO LINGER INTO TONIGHT. THE EDGE OF
THE LOWER CLOUD COVER IS EXPECTED TO LIFT FROM NORTHWEST TO SOUTHEAST
THROUGH TONIGHT AND INTO TOMORROW. SO WILL EXPECT TAF LOCATIONS SUCH
AS SYM TO IMPROVE FIRST...THEN FOLLOWED BY SME...LOZ...JKL...AND SJS
AS THE HIGHER CEILINGS MOVE IN FROM THE WEST AND NORTHWEST. BY
TOMORROW...HIGH PRESSURE SHOULD TAKE CONTROL OVER MUCH OF THE AREA
WITH VFR CONDITIONS EXPECTED BY THE END OF THE TAF PERIOD. WINDS WILL
BE LIGHT THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
427 PM EST MON DEC 29 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 403 PM EST MON DEC 29 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
EXTENDING FROM NRN QUEBEC THROUGH THE NRN PLAINS INTO THE ROCKIES.
THE NEXT SIGNIFICANT UPSTREAM SHORTWAVE TROUGH WAS DROPPING SOUTH
THROUGH NRN SASK/MANITOBA. AT THE SFC...1054 MB ARCTIC HIGH PRES OVER
ALBERTA EXTENDED INTO THE NRN PLAINS AND UPPER MS VALLEY AND NRN
LAKES RESULTING IN A FLOW OF VERY COLD AIR ACROSS LAKE SUPERIOR ON
NW WINDS. DESPITE 850 MB TEMPS NEAR -21C...LES HAS BEEN LIMITED BY
THE VERY DRY UPSTREAM CONDITIONS AS THE BACK EDGE OF THE CLOUDS WAS
CLOSER TO THE MI SHORE IN THE WEST AND NEAR THE CENTER OF THE NRN
LAKE. RADAR SHOWED MAINLY WEAK WIND PARALLEL BANDS INTO THE ERN
CWA.
TONIGHT...WITH THE LOSS OF DAYTIME MIXING AND ONSET OF LAND BREEZES
THE LES MAY BECOME BETTER ORGANIZED. THE PERSISTENT 290-300 FLOW LES
IS EXPECTED TO CONTINUE BUT WILL BE LIMITED BY 4K FT INVERSION
HEIGHTS AND A LACK OF ANY SUSTAINED AREAS OF LOW LEVEL CONV. THE LONGER
FETCH INTO THE EAST WILL SUPPORT SNOWFALL AMOUNTS IN THE 2 TO 4 INCH
RANGE WITH SLR VALUES NEAR 25/1...E OF MUNISING WHILE OVER THE WEST
ONLY 1 TO 3 INCH AMOUNTS ARE EXPECTED. WIND CHILL VALUES OVER THE
INTERIOR WEST COULD FALL INTO THE -20 TO -25 RANGE AS SFC TEMPS DROP
TO AROUND -8F. HOWEVER...WINDS SHOULD REMAIN LESS THAN 10 MPH.
TUESDAY...EXPECT THE WINDS TO BACK MORE WRLY AHEAD OF THE
SASK/MANITOBA SHORTWAVE TROUGH...ESPECIALLY IN THE AFTERNOON.
OTHERWISE...LIGHT TO MODERATE WNW FLOW LES WILL CONTINUE WITH 850 MB
TEMPS REMAINING NEAR -22C AND INVERSION HEIGHTS AROUND 4K FT. THE
STRONGEST LOW LEVEL CONV...INFLUENCED BY LAKE-INDUCED TROUGHING IS
EXPECTED OVER THE ERN LAKE WITH SOME STRONGER BANDS POSSIBLE
CLIPPING THE NE PORTION OF LUCE COUNTY. FOR NOW...EXPECT ADDITIONAL
ACCUMULATIONS IN THE 2 TO 4 INCH RANGE E OF P53 AND 1 TO 3 INCHES
INTO THE WEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EST MON DEC 29 2014
A BROAD UPPER TROUGH OVER CANADA AND THE GREAT LAKES REGION WILL
LEAD TO BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW
THROUGH THE FIRST WEEK OF 2015.
AT THE START OF THE PERIOD...THE AREA WILL STILL BE BETWEEN A
STRONG HIGH OVER WESTERN NEBRASKA AND A LOW JUST TO THE NORTH OF
HUDSON BAY. ALOFT...A SHORTWAVE WILL JUST BE DEPARTING THE AREA AND
BRINGING ONE LAST SURGE OF -21C 850MB TEMPS TO THE AREA.
THUS...EXPECT NORTHWEST FLOW LAKE EFFECT TO STILL BE ONGOING
TUESDAY EVENING. A SURFACE TROUGH DIVING SOUTHEAST FROM THE HUDSON
BAY LOW WILL LEAD TO BACKING FLOW ON TUESDAY NIGHT INTO WEDNESDAY
MORNING...SHIFTING THE LAKE EFFECT TO THE WESTERLY FLOW AREAS (THE
KEWEEANW AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE EAST OF
MUNISING). SNOWFALL AMOUNTS TUESDAY NIGHT CONTINUE TO LOOK LIGHT
AND FLUFFY AS INVERSION HEIGHTS ARE STILL IN THE 4-5KFT RANGE WITH
MUCH OF THE CLOUD LAYER IN THE DGZ. WILL FOLLOW THE SNOWFALL
AMOUNTS SEEN OVER THE LAST 12/24HRS AND HAVE THEM BE IN THE
1-4IN/12HRS RANGE.
TUESDAY NIGHT WILL BE ANOTHER COLD NIGHT AWAY FROM THE LAKE EFFECT
CLOUDS...WITH LOWS FALLING INTO THE SINGLE DIGITS AND LOWER TEENS
BELOW ZERO. WIND CHILLS WILL BECOME A CONCERN LATE IN THE NIGHT
INTO WEDNESDAY MORNING...AS THE WEST TO SOUTHWEST WINDS BEGIN TO
INCREASE WITH THE TIGHTENING PRESSURE GRADIENT. WHILE THIS WILL
LIKELY INCREASE MIXING AND IN TURN WARM TEMPS SLIGHTLY (HELPED BY
SOME MID CLOUDS MOVING IN)...THERE WILL STILL BE A PERIOD LATE
TUESDAY NIGHT INTO WEDNESDAY MORNING WHERE WIND CHILL VALUES WILL BE
IN THE -20 TO -30 DEGREE RANGE OVER THE INTERIOR LOCATIONS. WILL
CONTINUE TO MENTION THIS IN THE HWO AND AN ADVISORY MAY BEEN
NEEDED TOMORROW.
WITH THE LOW LEVEL WINDS TRYING TO BACK TOWARDS THE SOUTHWEST
DURING THE DAY WEDNESDAY...DID TRY TO SHOW BETTER TIMING ON THE
LAKE EFFECT SNOW. EXPECT IT TO TRY TO SHIFT OVER THE FAR NORTHERN
PART OF THE KEWEENAW BY MID DAY AND WELL OFFSHORE OVER THE
EAST. WINDS WILL BECOME QUITE GUSTY DURING THIS PERIOD...WITH MUCH
OF UPPER MICHIGAN EXPERIENCING GUSTS IN THE 25 TO 35MPH RANGE. BUT
OVER THE KEWEENAW PENINSULA AND CLOSER TO THE TIGHTER PRESSURE
GRADIENT...WOULD EXPECT GUSTS TO AT LEAST 40 MPH AND AT TIMES
45-50MPH. THESE WINDS COMBINED WITH THE FLUFFY LAKE EFFECT SEEN
OVER THE LAST COUPLE OF DAYS WILL LIKELY LEAD TO SIGNIFICANT
BLOWING SNOW DEVELOPING THROUGH THE DAY WEDNESDAY. THEN...AS STRONG
SHORTWAVE DIVES SOUTHEAST ACROSS THE UPPER GREAT LAKES REGION DURING
THE AFTERNOON AND THE SURFACE TROUGH DURING THE EARLY
EVENING...EXPECT WINDS TO SHIFT BACK TO THE WEST AND REFOCUS THE
LAKE EFFECT IN THE WESTERLY WIND AREAS. THINK THERE COULD BE A
PERIOD OF MODERATE SNOW AS THE WINDS TURN TO THE WEST...DUE TO
INVERSION HEIGHTS RISING TO 7KFT AND MUCH OF THE CLOUD STILL IN THE
DGZ. THERE ARE A COUPLE DOWNSIDES TO HIGHER SNOWFALL AMOUNTS (TIED
TO THE STRONG WINDS)...BUT THERE WILL STILL BE VERY POOR CONDITIONS
OVER THE KEWEENAW. FIRST...THE HIGH WINDS WILL LIMIT THE RESIDENCE
TIME OVER THE WESTERN LAKE AS THEY SHIFT TO THE WEST. SECOND...THE
STRONG WINDS WILL BREAK UP THE DENDRITES FROM THE FAVORABLE CLOUD
LAYER AND LEAD TO SMALLER/FRACTURED FLAKES. WHILE THIS WILL LIMIT
SNOWFALL AMOUNTS...IT WILL BE MORE EFFECTIVE AT REDUCING
VISIBILITIES AND WHEN COMBINED WITH THE BLOWING SNOW...WOULD EXPECT
VISIBILITIES BELOW 1/4 MILE AT TIMES LATE WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT. WILL CONTINUE TO MENTION THESE POOR CONDITIONS FOR
THE KEWEENAW IN THE HWO.
EXPECT NORTHWEST FLOW LAKE EFFECT TO REESTABLISH ON THURSDAY FOR
AREAS DOWNSTREAM FROM LAKE SUPERIOR. ELSEWHERE IN THE U.P...MODELS
DIFFER IN THEIR SOLUTIONS ON POTENTIAL SHORTWAVES ZIPPING
EAST-SOUTHEAST ACROSS THE AREA. AT TIMES...MODELS HAVE SHOWN LIGHT
SNOW ASSOCIATED WITH THESE QUICK WAVES THURSDAY AND AGAIN FRIDAY.
BOTH STRENGTH AND LOCATIONS HAS NOT BEEN CONSISTENT IN THE MODELS
OVER THE LAST 24 HOURS...SO WILL FOCUS LARGELY ON LAKE EFFECT
TURNING TO THE WESTERLY WIND LOCATIONS AND SHOW SLIGHT CHANCES
ELSEWHERE.
THE UNCERTAINTY CONTINUES INTO THE WEEKEND...AS MODELS DIFFER ON HOW
THE CLOSED UPPER LOW THAT DEVELOPS OVER THE SOUTHWEST CONUS TUESDAY
INTERACTS WITH THE NORTHERN STREAM JET AS IT SHIFTS EAST ACROSS THE
SOUTHERN CONUS. THE 12Z GFS/GEM SOLUTIONS MERGE THE UPPER LOW WITH
A MORE AMPLIFIED NORTHERN STREAM TROUGH AND THEN LIFT IT AND A
DEVELOPING SURFACE LOW NORTHEAST THROUGH THE LOWER GREAT LAKES
SATURDAY NIGHT. MEANWHILE...THE 12Z ECMWF AND ITS ENSEMBLE MEMBERS
SHOW A MUCH FLATTER NORTHERN STREAM TROUGH AND DON/T MERGE THE
WAVES UNTIL THE EAST COAST ON SUNDAY. THAT WOULD LEAD TO MORE OF A
NORTHERLY FLOW LAKE EFFECT FOR THE AREA. THIS WILL DEFINITELY BE
SOMETHING TO WATCH OVER THE COMING DAYS. EVEN IF THERE ISN/T A LOW
MOVING THROUGH THE LOWER GREAT LAKES...TEMPERATURES WILL BE COLD
ENOUGH FOR LAKE EFFECT SNOW AND WILL CONTINUE TO SHOW THE POTENTIAL
IN THE GRIDS FOR AREAS NEAR LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM EST MON DEC 29 2014
EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH
SLIGHTLY BETTER CONDITIONS AT SAW.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...COLD AIR ON NORTHWEST WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS WILL KEEP LES GOING AT IWD AND CMX. ALTHOUGH THIS
WIND DIRECTION IS NOT THE BEST FOR SAW TO GET SNOW...OFF AND ON
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE. EXPECT DAYTIME HEATING TO
HELP DISRUPT SOME OF THE STRONGER BANDS TODAY...BEFORE ANOTHER UPPER
LEVEL DISTURBANCE HELPS BOOST THE POTENTIAL FOR LAKE EFFECT SNOW
SHOWERS AT CMX ONCE AGAIN. AT THAT POINT WINDS OVER N WI AND FAR W
UPPER MI SHOULD BECOME MORE WRLY...LIMITING POTENTIAL FOR MUCH MORE
THAN FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 PM EST MON DEC 29 2014
EXPECT HEAVY FREEZING SPRAY BY TUESDAY AFTERNOON AND GALES FROM LATE
TUESDAY NIGHT THROUGH THURSDAY MORNING.
A RIDGE ACROSS THE UPPER GREAT LAKES WILL BUILD TUESDAY...AS VERY
STRONG ARCTIC HIGH PRESSURE INITIALLY AT 31.3 INCHES OVER SW CANADA
SINKS ACROSS MONTANA. LOOK FOR THE RIDGE OVER LAKE SUPERIOR TO SINK
SOUTH TUESDAY NIGHT. THIS WILL BE AS A HUDSON BAY LOW DRAGS A TROUGH
ACROSS LAKE SUPERIOR. THE LOW WILL DEEPEN OVER S HUDSON BAY
WEDNESDAY NIGHT AS IT BRINGS A REINFORCING TROUGH ACROSS LAKE
SUPERIOR. W GALES OF 35-45KTS ARE STILL ANTICIPATED /ALONG WITH
HEAVY FREEZING SPRAY TUESDAY NIGHT THROUGH THURSDAY MORNING AS
THE PRESSURE GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND
STRONG LOW TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND
WEAKEN SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
SE ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A
RIDGE TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO
1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263-
265>267.
GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO
7 AM EST /6 AM CST/ THURSDAY FOR LSZ162.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST
/6 AM CST/ THURSDAY FOR LSZ162-263.
HEAVY FREEZING SPRAY WARNING FROM 1 AM TUESDAY TO 1 PM EST
THURSDAY FOR LSZ264.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST /6 PM CST/
WEDNESDAY FOR LSZ241>245.
HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LSZ246-247.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
404 PM EST MON DEC 29 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 403 PM EST MON DEC 29 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
EXTENDING FROM NRN QUEBEC THROUGH THE NRN PLAINS INTO THE ROCKIES.
THE NEXT SIGNIFICANT UPSTREAM SHORTWAVE TROUGH WAS DROPPING SOUTH
THROUGH NRN SASK/MANITOBA. AT THE SFC...1054 MB ARCTIC HIGH PRES OVER
ALBERTA EXTENDED INTO THE NRN PLAINS AND UPPER MS VALLEY AND NRN
LAKES RESULTING IN A FLOW OF VERY COLD AIR ACROSS LAKE SUPERIOR ON
NW WINDS. DESPITE 850 MB TEMPS NEAR -21C...LES HAS BEEN LIMITED BY
THE VERY DRY UPSTREAM CONDITIONS AS THE BACK EDGE OF THE CLOUDS WAS
CLOSER TO THE MI SHORE IN THE WEST AND NEAR THE CENTER OF THE NRN
LAKE. RADAR SHOWED MAINLY WEAK WIND PARALLEL BANDS INTO THE ERN
CWA.
TONIGHT...WITH THE LOSS OF DAYTIME MIXING AND ONSET OF LAND BREEZES
THE LES MAY BECOME BETTER ORGANIZED. THE PERSISTENT 290-300 FLOW LES
IS EXPECTED TO CONTINUE BUT WILL BE LIMITED BY 4K FT INVERSION
HEIGHTS AND A LACK OF ANY SUSTAINED AREAS OF LOW LEVEL CONV. THE LONGER
FETCH INTO THE EAST WILL SUPPORT SNOWFALL AMOUNTS IN THE 2 TO 4 INCH
RANGE WITH SLR VALUES NEAR 25/1...E OF MUNISING WHILE OVER THE WEST
ONLY 1 TO 3 INCH AMOUNTS ARE EXPECTED. WIND CHILL VALUES OVER THE
INTERIOR WEST COULD FALL INTO THE -20 TO -25 RANGE AS SFC TEMPS DROP
TO AROUND -8F. HOWEVER...WINDS SHOULD REMAIN LESS THAN 10 MPH.
TUESDAY...EXPECT THE WINDS TO BACK MORE WRLY AHEAD OF THE
SASK/MANITOBA SHORTWAVE TROUGH...ESPECIALLY IN THE AFTERNOON.
OTHERWISE...LIGHT TO MODERATE WNW FLOW LES WILL CONTINUE WITH 850 MB
TEMPS REMAINING NEAR -22C AND INVERSION HEIGHTS AROUND 4K FT. THE
STRONGEST LOW LEVEL CONV...INFLUENCED BY LAKE-INDUCED TROUGHING IS
EXPECTED OVER THE ERN LAKE WITH SOME STRONGER BANDS POSSIBLE
CLIPPING THE NE PORTION OF LUCE COUNTY. FOR NOW...EXPECT ADDITIONAL
ACCUMULATIONS IN THE 2 TO 4 INCH RANGE E OF P53 AND 1 TO 3 INCHES
INTO THE WEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM EST MON DEC 29 2014
EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH
SLIGHTLY BETTER CONDITIONS AT SAW.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...COLD AIR ON NORTHWEST WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS WILL KEEP LES GOING AT IWD AND CMX. ALTHOUGH THIS
WIND DIRECTION IS NOT THE BEST FOR SAW TO GET SNOW...OFF AND ON
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE. EXPECT DAYTIME HEATING TO
HELP DISRUPT SOME OF THE STRONGER BANDS TODAY...BEFORE ANOTHER UPPER
LEVEL DISTURBANCE HELPS BOOST THE POTENTIAL FOR LAKE EFFECT SNOW
SHOWERS AT CMX ONCE AGAIN. AT THAT POINT WINDS OVER N WI AND FAR W
UPPER MI SHOULD BECOME MORE WRLY...LIMITING POTENTIAL FOR MUCH MORE
THAN FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 PM EST MON DEC 29 2014
EXPECT HEAVY FREEZING SPRAY BY TUESDAY AFTERNOON AND GALES FROM LATE
TUESDAY NIGHT THROUGH THURSDAY MORNING.
A RIDGE ACROSS THE UPPER GREAT LAKES WILL BUILD TUESDAY...AS VERY
STRONG ARCTIC HIGH PRESSURE INITIALLY AT 31.3 INCHES OVER SW CANADA
SINKS ACROSS MONTANA. LOOK FOR THE RIDGE OVER LAKE SUPERIOR TO SINK
SOUTH TUESDAY NIGHT. THIS WILL BE AS A HUDSON BAY LOW DRAGS A TROUGH
ACROSS LAKE SUPERIOR. THE LOW WILL DEEPEN OVER S HUDSON BAY
WEDNESDAY NIGHT AS IT BRINGS A REINFORCING TROUGH ACROSS LAKE
SUPERIOR. W GALES OF 35-45KTS ARE STILL ANTICIPATED /ALONG WITH
HEAVY FREEZING SPRAY TUESDAY NIGHT THROUGH THURSDAY MORNING AS
THE PRESSURE GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND
STRONG LOW TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND
WEAKEN SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
SE ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A
RIDGE TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO
1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263-
265>267.
GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO
7 AM EST /6 AM CST/ THURSDAY FOR LSZ162.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST
/6 AM CST/ THURSDAY FOR LSZ162-263.
HEAVY FREEZING SPRAY WARNING FROM 1 AM TUESDAY TO 1 PM EST
THURSDAY FOR LSZ264.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST /6 PM CST/
WEDNESDAY FOR LSZ241>245.
HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LSZ246-247.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...VOSS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
104 PM EST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST MON DEC 29 2014
TODAY AND TONIGHT WILL BE MARKED BY PERSISTENT COOL NW FLOW...WITH
DAYTIME HIGHS FALLING ANOTHER 5F FROM WHAT WAS REALIZED SUNDAY. A
WEAK SFC TROUGH SET UP ACROSS THE CWA WILL CONTINUE TO BE ERODED FOR
ALL BUT FAR E UPPER MI/LAKE SUPERIOR AS VERY STRONG 1060-1062MB
ARCTIC HIGH PRESSURE OVER CENTRAL BRITISH COLUMBIA AND ALBERTA THIS
MORNING.
EXPECT TO SEE SOME TEMPORARY IMPROVING CONDITIONS LES WISE FROM
DAYBREAK THROUGH THE EARLY AFTERNOON HOURS AS THE INITIAL SHORTWAVE
SHIFTS A BIT FARTHER TO OUR N. A SECODARY TROUGH/SHORTWAVE IS
BRINGING HIGH CLOUDS TO THE S TIP OF THE CWA THIS MORNING.
PERSISTENT OFF AND ON LES WILL CONTINUE OUR HIGH POP/LOW QPF
SCENARIO...WITH ONLY A FEW HUNDREDTHS IF THAT EVERY 6 HOURS. 850MB
TEMPS WILL GENERALLY RUN -17 TO -20C THROUGH TONIGHT. BETTER
CONVERGENCE WITH THE LOSS OF DAYTIME HEATING...AND THE APPROACH OF
YET ANOTHER SHORTWAVE WILL HELP BRING A LITTLE BETTER CHANCE OF
ACCUMULATING SNOW TO THE NW WIND SNOWBELTS. A COUPLE OF LOCATIONS IN
ALGER COUNTY COULD GET CLOSE TO ADVISORY SNOW TONIGHT IN CONVERGENT
BANDS OF LES SET UP IN ONE PLACE LONG ENOUGH. OTHERWISE COUNTY
AVERAGE IS RIGHT AROUND 3IN. SIMILAR TO THIS MORNING...CLOUD COVER
WILL MAKE ALL THE DIFFERENCE IN HOW COLD IT WILL GET TONIGHT. EXPECT
INTERIOR W HALF TO FALL INTO THE SINGLE DIGITS BELOW ZERO AGAIN.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM EST MON DEC 29 2014
EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH
SLIGHTLY BETTER CONDITIONS AT SAW.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...COLD AIR ON NORTHWEST WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS WILL KEEP LES GOING AT IWD AND CMX. ALTHOUGH THIS
WIND DIRECTION IS NOT THE BEST FOR SAW TO GET SNOW...OFF AND ON
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE. EXPECT DAYTIME HEATING TO
HELP DISRUPT SOME OF THE STRONGER BANDS TODAY...BEFORE ANOTHER UPPER
LEVEL DISTURBANCE HELPS BOOST THE POTENTIAL FOR LAKE EFFECT SNOW
SHOWERS AT CMX ONCE AGAIN. AT THAT POINT WINDS OVER N WI AND FAR W
UPPER MI SHOULD BECOME MORE WRLY...LIMITING POTENTIAL FOR MUCH MORE
THAN FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 AM EST MON DEC 29 2014
LOOK FOR A BETTER CHANCE OF FREEZING SPRAY AND STRONG WINDS TUESDAY
NIGHT THROUGH THURSDAY MORNING.
THE OVERALL PATTERN LOOKS LIKE THIS...A RIDGE ACROSS THE UPPER GREAT
LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE
INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK
FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS
WILL BE AS A HUDSON BAY LOW SWINGS A TROUGH ACROSS LAKE SUPERIOR.
THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A
REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-40KTS ARE
STILL ANTICIPATED /ALONG WITH THE POTENTIAL FOR HEAVY FREEZING
SPRAY/ LATE TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW
TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN
SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE
ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE
TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO
1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263-
265>267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO
7 AM EST /6 AM CST/ THURSDAY FOR LSZ162.
HEAVY FREEZING SPRAY WARNING FROM 1 AM TUESDAY TO 1 PM EST
THURSDAY FOR LSZ264.
HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LSZ246-247.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...VOSS
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1116 AM CST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM CST MON DEC 29 2014
THE SHORT TERM IS A BIT COMPLICATED. A COLD FRONT PASSED SOUTH
ACROSS THE CWA OVERNIGHT AND LIGHT SNOW HAS BROKEN OUT BEHIND IT.
MODELS ARE TRENDING LATER WITH THE BEGINNING OF SNOW. THE NAM AND
WRF...ALONG WITH THE HRRR INDICATE THAT THE SNOW ENTERING FROM THE
NORTH WILL HAVE A TOUGH TIME MAKING IT MUCH FARTHER SOUTH THAN
INTERSTATE 80 THIS AFTERNOON. AS THIS AREA OF SNOW STALLS AND
DISSIPATES...A MID-LEVEL PERTURBATION HEADS IN FROM THE WEST ACROSS
NORTHERN KANSAS ALONG WITH AN UPPER LEVEL JET MAXIMUM WILL HELP GET
SNOW GOING AGAIN...ESPECIALLY IN OUR FAR SOUTHWESTERN CWA. WE COULD
GET CLOSE TO THREE INCHES OF SNOW IN THESE AREAS...CONSIDERING A
GENERAL ENSEMBLE APPROACH TO MODEL QPF...ALONG WITH SNOW/LIQUID
WATER RATIOS 13 TO 1 FOR TONIGHT...WHICH IS FAIRLY TYPICAL. WENT
WITH A WINTER WEATHER ADVISORY IN OUR SOUTHWEST...CONSIDERING NOT
ONLY WE SHOULD JUST MEET SNOWFALL AMOUNT CRITERION...BUT THE
PRESSURE GRADIENT TODAY WILL BRING IN WIND FROM THE NORTH AT AROUND
20 MPH GUSTING TO 30 MPH. NUMERICAL MODELS ARE TRENDING LATER WITH
ENDING TIME...AND HAVE CONTINUED THIS ADVISORY INTO TUESDAY MORNING.
THIS COULD REDUCE VISIBILITY AS WELL. MY SNOW AMOUNTS MATCH UP
FAIRLY WELL WITH THE LATEST WPC GUIDANCE...WITH NEAR ONE INCH IN OUR
EAST TO THE 2 TO 4 INCH RANGE IN OUR WESTERN HALF OF THE CWA.
CONSIDERING THE GENERAL AGREEMENT BETWEEN THE NAM...NMM WRF...AND
SREF ENSEMBLES...I HAVE BUMPED UP CHANCES OF PRECIPITATION/SNOW
CONSIDERABLY...ESPECIALLY IN OUR SOUTHWEST FOR THIS AFTERNOON INTO
TONIGHT...BUT ALSO DELAYING THE ARRIVAL IN OUR SOUTHEAST A BIT
LONGER...CONSIDERING THAT THE NORTHERN BATCH OF SNOW SHOULD LOSE ITS
PUNCH BEFORE LONG. ALSO RAISED HIGH TEMPERATURES IN OUR NORTH
COMPARED TO THE PREVIOUS FORECAST... SINCE TEMPERATURES
ARE CURRENTLY 5 TO 7 DEGREES WARMER THAN THE EARLIER PREDICTED HIGH
FOR TODAY.
CONSIDERING THAT THE WIND SPEEDS WILL BE A BIT ELEVATED...EVEN LATE
TONIGHT...I DO NOT ANTICIPATE THAT LOWS WILL GET QUITE AS COOL AS
EARLIER PREDICTED...IN GENERAL...AND I HAVE BUMPED UP LOWS A COUPLE
OF DEGREES. I AM QUITE SKEPTICAL OF THE MID-LEVEL SKY COVER
ADVERTISED BY MODEL SOUNDINGS. MID-LEVEL SKY COVER IS FORECAST TO
HANG AROUND...DESPITE MUCH MORE DRY AND COLDER ARCTIC AIR IS MOVING
IN. I SUSPECT AT LEAST PARTIAL CLEARING COULD OCCUR IN OUR
NORTH/NORTHEAST BY THE END OF THE NIGHT. WITH THE WIND SPEEDS
ELEVATED...THIS ALONE SHOULD NOT HAVE AS MUCH OF AN EFFECT. HAVING
SAID THIS...WIND SPEEDS SHOULD BE HIGH ENOUGH TO NEED A WIND CHILL
ADVISORY ALONG AND NORTH OF HIGHWAY 6 LATE TONIGHT INTO TUESDAY
MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 530 AM CST MON DEC 29 2014
THE PRIMARY FORECAST CONCERN WILL CENTER AROUND THE BITTERLY COLD
TEMPERATURES TUESDAY THROUGH WEDNESDAY.
TUESDAY...SEVERAL FORECAST MODELS (00Z GEM...00Z ECMWF...06Z
NAM...AND A FEW WRF RUNS) ARE LINGERING THE LIGHT SNOW ACROSS OUR
SOUTHWESTERN ZONES INTO THE DAYLIGHT HOURS TUESDAY MORNING.
THEREFORE...HAVE INCREASED SNOW CHANCES TUESDAY MORNING ACROSS
SOUTHWESTERN ZONES...SOUTHWEST OF THE TRI-CITIES. SNOW WILL BE IN
THE PROCESS OF ENDING FROM NORTH TO SOUTH TUESDAY MORNING WITH ANY
ADDITIONAL ACCUMULATION AFTER SUNRISE TUESDAY MORNING LIKELY LESS
THAN ONE HALF INCH AND PRIMARILY CONFINED TO COUNTIES CURRENTLY
UNDER THE WINTER WEATHER ADVISORY. THE MORE WIDESPREAD ISSUE ACROSS
OUR FORECAST AREA WILL BE THE COLD AS WIND CHILL VALUES WILL LIKELY
FALL INTO THE -20 TO -30F RANGE ACROSS MOST OF OUR NEBRASKA COUNTIES
EXCEPT FOR THE SOUTHERN MOST TIER OF COUNTIES. OUR WIND CHILL
ADVISORY CRITERIA IS -20 TO -30F AND THEREFORE A WIND ADVISORY IS
NOW IN EFFECT FOR MOST OF OUR NEBRASKA COUNTIES FROM LATE TONIGHT
THROUGH TUESDAY MORNING. A NORTH WIND OF AROUND 15 TO 20 MPH GUSTING
TO AROUND 25 MPH ALONG WITH TUESDAY MORNING LOWS OF 0 TO -7F SHOULD
BE SUFFICIENT TO PUSH OUR WIND CHILLS DOWN INTO ADVISORY CRITERIA.
COLD AIR WILL CONTINUE TO FILTER INTO THE REGION THROUGHOUT THE DAY
MAKING IT HARD FOR TEMPERATURES TO RISE. IN ADDITION...MID TO HIGH
CLOUDS ARE EXPECTED THROUGH MUCH OF THE DAY AND ALONG WITH OUR
CURRENT SNOW COVER WILL ALSO MAKE IT DIFFICULT FOR TEMPERATURES TO
RISE. THEREFORE...WILL CALL FOR HIGHS ONLY IN THE 5 TO 10F RANGE.
TUESDAY NIGHT INTO WEDNESDAY...THE COLDEST NIGHT OF THE WEEK WILL
LIKELY BY TUESDAY NIGHT AS WE SEE CLEARING SKIES AND DECREASING
WINDS...WHICH WILL HELP LOWS FALL INTO THE -1 TO -10F RANGE ACROSS
THE FORECAST AREA. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THE WIND WILL BE
LIGHTER...THE AIR TEMPERATURES WILL BE COLDER SO THAT THE WIND CHILL
VALUES TUESDAY NIGHT/WEDNESDAY MORNING WILL LIKELY BE RATHER
COMPARABLE TO THE WIND CHILL VALUES EXPECTED TONIGHT INTO TUESDAY
MORNING. THE MODERATION IF YOU CAN CALL IT THAT WILL BEGIN DURING
THE DAY ON WEDNESDAY WITH A WEST SOUTHWEST WIND HELPING HIGHS TO
CLIMB BACK INTO THE TEENS.
THURSDAY THROUGH SUNDAY...A CUT OFF UPPER AREA OF LOW PRESSURE OVER
THE DESERT SOUTHWEST ON THURSDAY WILL SLOWLY TRACK ACROSS THE
SOUTHERN PLAINS FRIDAY AND SATURDAY...AND INTO THE MISSISSIPPI
VALLEY BY SUNDAY. MOST FORECAST MODELS KEEP THIS STORM TRACK FAR
ENOUGH SOUTH THAT WE WILL LIKELY BE DRY ACROSS OUR FORECAST AREA.
FOR THE SAKE OF A COUPLE OF OUTLYING MODELS WILL ALLOW THE SLIGHT
CHANCE OF SNOW ACROSS SOUTHEASTERN ZONES ON FRIDAY/FRIDAY NIGHT TO
REMAIN IN THE FORECAST...BUT CONFIDENCE IS LOW IN SEEING MEASURABLE
PRECIPITATION. THERE SHOULD BE SOME ADDITIONAL MODERATION IN
TEMPERATURES THURSDAY THROUGH SATURDAY AHEAD OF THE SOUTHERN STORM
SYSTEM WITH COLDER AIR FILTERING BACK IN BEHIND THE DEPARTING
SOUTHERN STORM SYSTEM ON SUNDAY. OVERALL...IT WILL REMAIN A COLD
PERIOD WITH HIGHS GENERALLY IN THE 20S FOR MOST AREAS...TO MAYBE
LOWER 30S SOUTH.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1111 AM CST MON DEC 29 2014
THE FIRST ROUND OF LIGHT SNOW WILL PERSIST THRU THE AFTN WHICH IS
ASSOCIATED WITH MID LEVEL FRONTOGENESIS FOLLOWING THE PASSAGE OF A
COLD FRONTAL BOUNDARY. ANOTHER ROUND OF SNOW IS EXPECTED TO
DEVELOP THIS EVENING EVENING AND TONIGHT AHEAD OF A TROUGH MOVING
OUT OF THE ROCKIES. DRIER AIR ADVECTING IN FROM THE NORTH WILL
EVENTUALLY CAUSE SNOW TO END AT THE TERMINALS. WINDS WILL BE
STEADY FROM A NORTHERLY DIRECTION.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR NEZ039>041-046>049-060>064-072>077.
WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR NEZ082-083.
KS...WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR KSZ005-017-
018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...WESELY
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1231 PM EST MON DEC 29 2014
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH ACROSS THE AREA TODAY. BEHIND THE
FRONT...HIGH PRESSURE WILL BUILD ACROSS THE NATIONS MID SECTION
AND EXTEND INTO THE GREAT LAKES AND OHIO VALLEY THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE FOR MINOR CHANGES. LATEST HRRR CONTINUE TO SHOW SOME SNOW
SHOWERS ACROSS NW PA THIS AFTERNOON. WILL CONTINUE WITH A 20 POP.
ORIGINAL...HIGH CLOUDS DRIFTING EAST OVERNIGHT HOWEVER SATELLITE
SHOWS STRATUS DEVELOPING ACROSS THE CENTRAL AND EAST LAKESHORE
COUNTIES AND A LARGE AREA OF STRATUS ACROSS LOWER MI AND NORTH OF
LAKE ERIE DRIFTING SOUTH. ELSEWHERE SKIES MOSTLY CLEAR. FOR THE
EARLY MORNING AM EXPECTING STRATUS TO CONTINUE TO EXPAND AS LOW
LEVEL LOW COMES OFF THE LAKE. THE STRATUS ACROSS LOWER MI AND
CANADA NORTH OF LAKE ERIE HAS TENDED TO DISSIPATE ON THE SOUTHERN
SIDE SLOWING ITS PROGRESSION. FOLLOWING THE NAM 925MB RH ONE WOULD
EXPECT THE STRATUS TO EITHER MOVE IN FROM THE NORTHWEST OR DEVELOP
ACROSS THE AREA HOWEVER THERE ARE PLENTY OF HOLES AND WITH DRY AIR
ABOVE...ANY MIXING WOULD TEND TO ALLOW MORE HOLES TO DEVELOP. FOR
NOW AWAY FROM THE LAKE...WILL BEGIN WITH PC AND THEN TRANSITION TO
MC OR PS. GUIDANCE HIGHS IN THE LOW TO MID 30S LOOK FINE WITH ONLY
MINOR ADJUSTMENTS.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL CONTINUE TO NOSE INTO THE AREA TONIGHT THROUGH
WEDNESDAY AS IT DROPS THROUGH THE CENTRAL PLAINS. GIVEN ITS TRACK
HOWEVER COLD ADVECTION WILL CONTINUE THROUGH THE PERIOD WITH BOTH
THE NAM AND GFS SHOWING -16 TO -18C BY WEDNESDAY 12Z. OUTSIDE OF
ANY LAKE EFFECT THE AIRMASS REMAINS FAIRLY DRY THROUGH THE SHORT
TERM PERIOD. GIVEN THE TEMP FALL HOWEVER WILL CONTINUE WITH CHANCE
POPS ALL ALONG THE LAKESHORE COUNTIES FROM LORAIN CO EAST
BEGINNING TUESDAY AFTERNOON...INCREASING TO LIKELY ASHTABULA ERIE
CRAWFORD TUESDAY NIGHT AS LAKE-850MB TEMP DIFFERENCE BECOMES
ENOUGH FOR MODERATE INSTABILITY AS SHOWN ON BUFKIT KERI FORECAST
SOUNDING. WILL CONTINUE WITH CHANCE POPS WEDNESDAY. WINDS BACK
TO SOUTHWEST WEDNESDAY NIGHT TAKING ANY BANDS OFFSHORE. THURSDAY
NIGHT THE GFS SHOWS ANOTHER TROF DROPPING SOUTH ACROSS THE LAKES
BRINGING MOISTURE TO THE AREA. WILL BRING CHANCE POPS BACK TO THE
NORTHERN COUNTIES WITH HIGHEST POPS IN THE SNOWBELT. TEMPS
GENERALLY BELOW NORMAL.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LONG RANGE MODELS HAD SOME DIFFERENCES TO THEIR SOLUTIONS ON
SATURDAY WITH THE EUROPEAN BEING THE DRIEST COMPARED TO THE WET GFS
MODEL. LATEST RUN OF THE EUROPEAN AT 00Z IS NOW INDICATING A WETTER
SOLUTION IN LINE WITH THE GFS SO WILL BE LEANING IN THE DIRECTION OF
SPREADING PRECIPITATION INTO THE REGION DURING THE DAY SATURDAY. I
GUESS UNTIL I SEE SOME CONSISTENCY IN THE MODELS FOR WARMING THINGS
UP ON SATURDAY...I WILL NOT GET TOO CRAZY IN RAISING TEMPERATURES
FOR HIGHS. LATEST GUIDANCE SUGGESTS A FAIRLY BRISK SOUTH TO
SOUTHWESTERLY FLOW ON SATURDAY INDICATING TEMPERATURES WILL BE MUCH
WARMER THAN WE HAVE CURRENTLY FORECAST. SO...I GUESS I WOULD EXPECT
TEMPERATURES TRENDING UPWARD OVER THE NEXT FEW DAYS IF MODELS ARE
PERSISTENT.
ONCE SURFACE LOW GOES BY ON SUNDAY...COLD AIR ADVECTION WILL RETURN
TO THE REGION. THIS WILL LIKELY SET UP SOME LAKE EFFECT SNOW SHOWERS
BY SUNDAY NIGHT INTO MONDAY. DEPENDING ON THE TIMING OF THE LOW
PASSAGE...SOME COULD BEGIN AS EARLY AS LATE SUNDAY AFTERNOON.
COLD AIR ADVECTION LOOKS LIKE IT WILL BE A GLANCING BLOW AS HIGH
PRESSURE BUILDS SOUTHEAST ACROSS THE GREAT LAKES BY THE MIDDLE OF
THE WEEK.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WEAK COLD FRONT CROSSING THE AREA FOR THE AFTERNOON HOURS. HIGH
PRESSURE IN ITS WAKE. FRONT MAY GENERATE A FLURRY IN NW PA WITH
LITTLE ADDITIONAL AVIATION IMPACT BEYOND THAT OF THE CURRENT MVFR
CEILINGS TODAY. CEILINGS WILL REMAIN MVFR UNTIL LATE IN THE
AFTERNOON WHEN THEY HAVE A CHANCE AT IMPROVING TO VFR. MVFR
CEILINGS REDEVELOP OVERNIGHT. LIGHT NORTH WINDS 10 KNOTS OR LESS.
.OUTLOOK...AREAS OF NON VFR TUESDAY AFTERNOON THROUGH WEDNESDAY
AND THEN AGAIN THURSDAY NIGHT THROUGH FRIDAY NIGHT.
&&
.MARINE...
LAKE IS EXPECTED TO BE FAIRLY QUIET TODAY AND TONIGHT BUT WINDS ARE
EXPECTED TO PICK UP SPEED BY TUESDAY AFTERNOON INTO WEDNESDAY. FLOW
WILL GRADUALLY SHIFT AROUND TO THE SOUTHWEST BY WEDNESDAY NIGHT AND
INCREASE EVEN FURTHER. I WOULD IMAGINE THAT AT SOME POINT WE ARE
GOING TO NEED A SMALL CRAFT ADVISORY TUESDAY AND POSSIBLY GALES BY
WEDNESDAY NIGHT. SO WILL INCLUDE A MENTION OF GALE POTENTIAL IN THE
HAZARDOUS WEATHER OUTLOOK. WINDS STAY PRETTY GUSTY OUT OF THE WEST
SOUTHWEST INTO THURSDAY WHEN THEY EVENTUALLY DIMINISH.
UNFORTUNATELY...SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED GOING
INTO FRIDAY AS WINDS DO NOT DIMINISH ENOUGH.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK/KUBINA
SHORT TERM...TK
LONG TERM...LOMBARDY
AVIATION...OUDEMAN
MARINE...LOMBARDY
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1038 AM CST MON DEC 29 2014
.UPDATE...
TWEAKED SKY COVER AND TEMPERATURES THIS AFTERNOON ACROSS
THE AREA.
&&
.DISCUSSION...
TODAY MAY BE THE WARMEST DAY OF THE WEEK IN MANY LOCATIONS.
MUCH COLDER AIR WILL ARRIVE TONIGHT.
LATEST WEATHER MAP SHOWED A WEAK SURFACE LOW OVER FAR WESTERN
NORTH TEXAS NEAR KNOX CITY. LOW LEVEL MOISTURE IS INCREASING
NORTH AND EAST OF THIS LOW...WHICH WILL ALLOW FOR CLOUDS TO
DEVELOP THIS AFTERNOON IN MANY AREAS. THUS...TWEAKED SKY COVER
UPWARDS THIS AFTERNOON NORTH AND EAST OF A HOBART TO MARIETTA
LINE. LATEST HRRR RUNS HAVE A GREAT HANDLE ON THIS. MOISTURE
APPEARS TO BE TOO SHALLOW FOR PRECIPITATION...AT LEAST THROUGH
6 PM TODAY.
HIGHS TODAY WILL BE TRICKY WITH INCREASING CLOUD COVER.
GENERALLY TWEAKED THEM DOWNWARD 1 TO 3 DEGREES FROM JUST EAST
OF OKLAHOMA CITY TO DURANT...AND UPWARD 1 TO 3 DEGREES OVER
NORTHERN OKLAHOMA WITH A SLOWER ARRIVAL OF THE ARCTIC FRONT.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 534 AM CST MON DEC 29 2014/
AVIATION...
A COLD FRONT IS EXPECTED TO MOVE IN THIS AFTERNOON...BRINGING
BREEZY NORTH WINDS BEHIND IT. MVFR CEILINGS MAY MOVE INTO CENTRAL
OKLAHOMA AROUND NOON...BUT BAND IS EXPECTED TO BE FAIRLY NARROW SO
CONFIDENCE IS LOW THAT IT WILL AFFECT KOKC AND KOUN. LATE TONIGHT
INTO TOMORROW MORNING MAY SEE SOME LOW CLOUDS IN THE MVFR RANGE.
PREV DISCUSSION... /ISSUED 402 AM CST MON DEC 29 2014/
DISCUSSION...
SPECIAL WEATHER STATEMENT/WINTER STORM OUTLOOK WILL BE ISSUED
SHORTLY.
OVERALL...LITTLE CHANGE TO GOING FORECAST WITH SEVERAL EPISODES OF
IMPACTING WINTER WEATHER EXPECTED THE NEXT SEVERAL DAYS.
CONFIDENCE IS INCREASING THAT ADVISORIES WILL LIKELY BE ISSUED
MID-LATE WEEK AND WARNINGS CANNOT BE RULED OUT. FIRST ORDER WILL
BE INTRUSION OF ARCTIC AIR AND LOW WIND CHILL VALUES TONIGHT
THROUGH WEDNESDAY. COLDEST READINGS...TEENS AND SINGLE DIGITS
BELOW ZERO...WILL BE POSSIBLE OVER AT LEAST NORTHWEST HALF OF
OKLAHOMA. A WIND CHILL ADVISORY MAY BE ISSUED LATER TODAY OR
TONIGHT. ALSO...LIGHT SNOW WILL BE POSSIBLE ACROSS FAR WESTERN
OKLAHOMA TUESDAY AND TUESDAY NIGHT WITH UPSLOPE EVENT EXPECTED TO
UNFOLD BEHIND ARCTIC FRONT. AROUND AN INCH OF SNOW POSSIBLE ACROSS
FAR NORTHWEST AND WEST-CENTRAL OKLAHOMA.
IN THE WAKE OF THE SUBZERO WIND CHILLS AND SCATTERED SNOW ACROSS
FAR WESTERN OKLAHOMA...ATTENTION WILL TURN TOWARD THURSDAY THROUGH
EARLY FRIDAY AS FREEZING RAIN AND SLEET EVENT UNFOLDS. WE AGREE
MOST STRONGLY WITH PARALLEL-GFS (P-GFS) AND ECM WITH OVERALL ARE
IN REASONABLE AGREEMENT LATE WEEK INTO WEEKEND. FOR THE THURSDAY
INTO FRIDAY SCENARIO...OPERATIONAL GFS APPEARS TO ERODE BOUNDARY
LAYER COLD AIR MUCH TOO QUICKLY. ECM/P-GFS DRIER AND SLOWER TO
ERODE COLD AIR WITH WEAK WINDS AND PERSISTENT E/W LOW LEVEL RIDGE
ENTRENCHED OVER REGION. THEY MAY BE TOO FAST. FORECAST SOUNDINGS
STILL POINT TO DOMINANT PRECIP TYPE OF SLEET WITH RAIN AND
FREEZING RAIN AT TIMES. SNOW APPEARS TO BE A NON-ISSUE DURING THIS
TIME PERIOD. HEAVIEST AMOUNTS ARE CONSISTENT IN THE MODELS WHICH
IS OVER SOUTH-CENTRAL INTO SOUTHEAST PARTS OF OKLAHOMA. OVERALL...
THE ECM AND P-GFS WHICH WE ARE BASING FORECAST ON HAS MUCH LOWER
QPF THAN THE OPERATIONAL GFS. DURING THE DAY FRIDAY...TEMPS SHOULD
WARM JUST ENOUGH FOR RAIN OVER NORTH TEXAS AND AT LEAST THE
SOUTHERN HALF TO THREE-QUARTERS OF OKLAHOMA. SOME LIGHT SLEET OR
FREEZING RAIN STILL LOOKS POSSIBLE OVER NORTHERN OKLAHOMA.
AS UPPER SYSTEM PULLS OUT SATURDAY-SUNDAY...MUCH OF THE AREA WILL
LIKELY BE IN WARM SECTOR AND MAINLY LIQUID. TRACK OF UPPER LOW
STILL A BIT UNCERTAIN BUT P-GFS IS A GOOD COMPROMISE BETWEEN THE
MUCH SLOWER AND FARTHER SOUTH ECM...AND THE FASTER FARTHER NORTH
GFS. MOD-HEAVY SNOW CHANCES ON NORTH/WEST PERIPHERY OF MID LEVEL
CYCLONE EXPECTED TO BE CONFINED TO NORTHERN OKLAHOMA AND AREAS
NORTH.
ANOTHER SHOT OF VERY COLD AIR LOOKS LIKELY AFTER THIS STORM SYSTEM
SHIFTS EAST. GFS AND P-GFS MUCH COLDER THAN ECM WITH THIS PART OF
THE FORECAST BEYOND THIS PACKAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 43 23 31 13 / 0 10 10 10
HOBART OK 44 21 29 11 / 0 0 20 20
WICHITA FALLS TX 53 26 36 17 / 0 10 10 10
GAGE OK 38 12 18 3 / 0 20 30 30
PONCA CITY OK 42 19 25 5 / 0 10 10 10
DURANT OK 42 29 43 23 / 0 10 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
03/17
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1120 AM CST MON DEC 29 2014
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1032 AM CST MON DEC 29 2014/
UPDATE...
AS OF 10AM...TEMPERATURES ARE GENERALLY IN THE 30S ACROSS THE
ENTIRE FA THIS MORNING. CLOUD COVER CONTINUES TO HANG TOUGH AS
NORTHEAST WINDS KEEP THE MOISTURE IN PLACE. NOT MUCH WARMING IS
ANTICIPATED FOR THE REST OF THE DAY DUE TO THIS. HIGHS TODAY WILL
TOP OUT AROUND 40 DEGREES IN THE NORTH...WITH LOW TO MID 40S TO
THE SOUTH.
QUICK UPDATE TO REMOVE LIGHT PRECIP IN GRIDS...ADJUST
CLOUD COVER...AND LOWER TEMPERATURES A COUPLE OF DEGREES.
AC3
&&
.PREV DISCUSSION... /ISSUED 452 AM CST MON DEC 29 2014/
DISCUSSION...
EARLY THIS MORNING...SATELLITE SHOWED THAT LOW CLOUDS COVERED THE
MIDSOUTH. ANY CLEARING HAS STALLED AND THE LOW CLOUDS WERE EXPANDING
IN COVERAGE. TEMPERATURES WERE MOSTLY IN THE 30S EXCEPT FOR LOWER
40S ACROSS PORTIONS OF NORTHEAST MS. WINDS WERE NORTHERLY ABOUT 5 TO
10 MPH. PATCHY LIGHT RAIN LINGERED FROM PORTIONS OF SOUTHWEST TN
INTO NORTH MS.
A STRONG SURFACE HIGH PRESSURE OF ABOUT 1058 MB WILL EXTEND FROM
SOUTHWEST CANADA TO THE MIDSOUTH TODAY. LOW CLOUDS WILL SLOWLY
DECREASE FROM THE WEST ACROSS PORTIONS OF NORTHEAST AR...BUT LOW
CLOUDS WILL PERSIST EAST OF THE MS RIVER ALL DAY. IN ADDITION...HIGH
LEVEL CLOUDS WILL SPREAD IN FROM THE WEST. TEMPERATURES WILL BE HELD
DOWN BY THE CLOUDS AND WILL BE BELOW NORMAL. BASED ON THE HRRR AND
NAM...KEPT IN AREAS OF DRIZZLE AND A SLIGHT CHANCE OF RAIN FROM
SOUTHWEST TN ALONG THE TN RIVER INTO PORTIONS OF NORTHEAST MS EARLY
THIS MORNING.
FOR TONIGHT...DID NOT CLEAR THE SKIES QUITE AS FAST AS SOME OF THE
GUIDANCE INDICATES WITH 925 MB WINDS FROM THE NORTHEAST HELPING TO
HOLD IN THE LOW CLOUDS ESPECIALLY EAST OF THE MS RIVER.
OTHERWISE...COLD HIGH PRESSURE WILL EXTEND INTO THE MIDSOUTH FROM
THE NORTH WITH PRECIPITATION FREE CONDITIONS.
SUNSHINE WILL RETURN TO THE MIDSOUTH TUESDAY AS THE STRONG SURFACE
HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. HIGH TEMPERATURES WILL
REMAIN BELOW NORMAL TUESDAY.
FOR WEDNESDAY...A SURFACE HIGH OF 1040 MB IS FORECAST TO BE CENTERED
OVER OK AND WILL DOMINATE MIDSOUTH WEATHER. SKIES WILL BE MOSTLY
SUNNY BUT IT WILL BE COLD.
WEDNESDAY AND THURSDAY MORNINGS WILL SEE LOW TEMPERATURES DIP INTO
THE 20S AREAWIDE WITH POSSIBLY SOME UPPER TEENS ACROSS THE EXTREME
NORTHERN LOCATIONS.
NEW YEARS DAY WILL CONTINUE COLD WITH INCREASING CLOUDS FROM THE
WEST DURING THE DAY. THE BLENDED GUIDANCE INDICATES A SLIGHT CHANCE
OF RAIN SPREADING INTO PORTIONS OF EAST CENTRAL AR AND NORTH MS
BY LATE AFTERNOON AS OVERRUNNING DEVELOPS.
THE OVERRUNNING PATTERN WILL STRENGTHEN THURSDAY NIGHT WITH A WARM
FRONT ALONG THE GULF COAST. A CLOSED UPPER LEVEL LOW OVER THE
SOUTHWESTERN UNITED STATES WILL MOVE SLOWLY EASTWARD. RAIN IS
FORECAST TO SPREAD ACROSS THE MIDSOUTH. A WINTRY MIXTURE OF
PRECIPITATION CONSISTING OF SLEET...RAIN...AND POSSIBLY FREEZING
RAIN IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING ACROSS PORTIONS
OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...INTO PORTIONS OF
WEST TENNESSEE. THE AFFECTED AREA IS MAINLY ALONG AND NORTH OF A
LINE FROM HARRISBURG ARKANSAS TO COVINGTON TENNESSEE TO SAVANNAH
TENNESSEE. AT THIS TIME...ANY ACCUMULATIONS ARE EXPECTED TO BE
LIGHT. THE PRECIPITATION IS EXPECTED TO CHANGE TO ALL RAIN BY MID-
MORNING FRIDAY. BRIEF SLEET MAY OCCUR JUST TO THE SOUTH OF THIS AREA
THURSDAY NIGHT BEFORE CHANGING TO RAIN WITH TEMPERATURES ABOVE
FREEZING.
FRIDAY INTO SATURDAY LOOK VERY WET FOR THE MIDSOUTH. THE UPPER LEVEL
LOW WILL SLOWLY APPROACH FROM THE WEST WITH THE WARM FRONT TO THE
SOUTH PUSHING ONLY SLOWLY NORTHWARD. MODELS DIFFER ON THE
DEVELOPMENT OF A SURFACE LOW ALONG THE FRONT. PRECIPITABLE WATER WILL
BE ON THE INCREASE WITH VALUES REACHING GREATER THAN 1.5 INCHES
ACROSS PORTIONS OF THE REGION BY FRIDAY NIGHT / SATURDAY. ELEVATED
INSTABILITY WILL ALSO INCREASE AS THE CLOSED UPPER LOW AND SOUTHWARD
EXTENDING UPPER LEVEL TROUGH APPROACHES. SCATTERED THUNDERSTORMS CAN
BE EXPECTED BY FRIDAY NIGHT AND CONTINUING INTO SATURDAY / SATURDAY
NIGHT. RAIN MAY BE LOCALLY HEAVY...HELD OFF MENTIONING THIS THREAT
IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW UNTIL CONFIDENCE INCREASES.
IT IS POSSIBLE THUNDERSTORMS TO OUR SOUTH COULD CUT US OFF FROM THE
GREATER MOISTURE AND RAINFALL. THE UPPER LEVEL TROUGH / ASSOCIATED
COLD FRONT IS FORECAST THROUGH THE REGION SATURDAY NIGHT WITH A
LINGERING CHANCE OF RAIN SUNDAY.
JCL
&&
.AVIATION...
18Z TAF CYCLE
IT APPEARS THAT MVFR CIGS...WITH INITIAL IFR CONDITIONS AT
TUP...WILL CONTINUE THROUGH MOST OF THIS TAF PERIOD. THE BEST
POSSIBILITY FOR VFR WEATHER WILL BE AT JBR AND MKL. NORTHEAST
WINDS AT 6-8 KTS WILL INCREASE WITH A FEW GUSTS LATE.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1032 AM CST MON DEC 29 2014
.UPDATE...
AS OF 10AM...TEMPERATURES ARE GENERALLY IN THE 30S ACROSS THE
ENTIRE FA THIS MORNING. CLOUD COVER CONTINUES TO HANG TOUGH AS
NORTHEAST WINDS KEEP THE MOISTURE IN PLACE. NOT MUCH WARMING IS
ANTICIPATED FOR THE REST OF THE DAY DUE TO THIS. HIGHS TODAY WILL
TOP OUT AROUND 40 DEGREES IN THE NORTH...WITH LOW TO MID 40S TO
THE SOUTH.
QUICK UPDATE TO REMOVE LIGHT PRECIP IN GRIDS...ADJUST
CLOUD COVER...AND LOWER TEMPERATURES A COUPLE OF DEGREES.
AC3
&&
.PREV DISCUSSION... /ISSUED 452 AM CST MON DEC 29 2014/
DISCUSSION...
EARLY THIS MORNING...SATELLITE SHOWED THAT LOW CLOUDS COVERED THE
MIDSOUTH. ANY CLEARING HAS STALLED AND THE LOW CLOUDS WERE EXPANDING
IN COVERAGE. TEMPERATURES WERE MOSTLY IN THE 30S EXCEPT FOR LOWER
40S ACROSS PORTIONS OF NORTHEAST MS. WINDS WERE NORTHERLY ABOUT 5 TO
10 MPH. PATCHY LIGHT RAIN LINGERED FROM PORTIONS OF SOUTHWEST TN
INTO NORTH MS.
A STRONG SURFACE HIGH PRESSURE OF ABOUT 1058 MB WILL EXTEND FROM
SOUTHWEST CANADA TO THE MIDSOUTH TODAY. LOW CLOUDS WILL SLOWLY
DECREASE FROM THE WEST ACROSS PORTIONS OF NORTHEAST AR...BUT LOW
CLOUDS WILL PERSIST EAST OF THE MS RIVER ALL DAY. IN ADDITION...HIGH
LEVEL CLOUDS WILL SPREAD IN FROM THE WEST. TEMPERATURES WILL BE HELD
DOWN BY THE CLOUDS AND WILL BE BELOW NORMAL. BASED ON THE HRRR AND
NAM...KEPT IN AREAS OF DRIZZLE AND A SLIGHT CHANCE OF RAIN FROM
SOUTHWEST TN ALONG THE TN RIVER INTO PORTIONS OF NORTHEAST MS EARLY
THIS MORNING.
FOR TONIGHT...DID NOT CLEAR THE SKIES QUITE AS FAST AS SOME OF THE
GUIDANCE INDICATES WITH 925 MB WINDS FROM THE NORTHEAST HELPING TO
HOLD IN THE LOW CLOUDS ESPECIALLY EAST OF THE MS RIVER.
OTHERWISE...COLD HIGH PRESSURE WILL EXTEND INTO THE MIDSOUTH FROM
THE NORTH WITH PRECIPITATION FREE CONDITIONS.
SUNSHINE WILL RETURN TO THE MIDSOUTH TUESDAY AS THE STRONG SURFACE
HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. HIGH TEMPERATURES WILL
REMAIN BELOW NORMAL TUESDAY.
FOR WEDNESDAY...A SURFACE HIGH OF 1040 MB IS FORECAST TO BE CENTERED
OVER OK AND WILL DOMINATE MIDSOUTH WEATHER. SKIES WILL BE MOSTLY
SUNNY BUT IT WILL BE COLD.
WEDNESDAY AND THURSDAY MORNINGS WILL SEE LOW TEMPERATURES DIP INTO
THE 20S AREAWIDE WITH POSSIBLY SOME UPPER TEENS ACROSS THE EXTREME
NORTHERN LOCATIONS.
NEW YEARS DAY WILL CONTINUE COLD WITH INCREASING CLOUDS FROM THE
WEST DURING THE DAY. THE BLENDED GUIDANCE INDICATES A SLIGHT CHANCE
OF RAIN SPREADING INTO PORTIONS OF EAST CENTRAL AR AND NORTH MS
BY LATE AFTERNOON AS OVERRUNNING DEVELOPS.
THE OVERRUNNING PATTERN WILL STRENGTHEN THURSDAY NIGHT WITH A WARM
FRONT ALONG THE GULF COAST. A CLOSED UPPER LEVEL LOW OVER THE
SOUTHWESTERN UNITED STATES WILL MOVE SLOWLY EASTWARD. RAIN IS
FORECAST TO SPREAD ACROSS THE MIDSOUTH. A WINTRY MIXTURE OF
PRECIPITATION CONSISTING OF SLEET...RAIN...AND POSSIBLY FREEZING
RAIN IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING ACROSS PORTIONS
OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...INTO PORTIONS OF
WEST TENNESSEE. THE AFFECTED AREA IS MAINLY ALONG AND NORTH OF A
LINE FROM HARRISBURG ARKANSAS TO COVINGTON TENNESSEE TO SAVANNAH
TENNESSEE. AT THIS TIME...ANY ACCUMULATIONS ARE EXPECTED TO BE
LIGHT. THE PRECIPITATION IS EXPECTED TO CHANGE TO ALL RAIN BY MID-
MORNING FRIDAY. BRIEF SLEET MAY OCCUR JUST TO THE SOUTH OF THIS AREA
THURSDAY NIGHT BEFORE CHANGING TO RAIN WITH TEMPERATURES ABOVE
FREEZING.
FRIDAY INTO SATURDAY LOOK VERY WET FOR THE MIDSOUTH. THE UPPER LEVEL
LOW WILL SLOWLY APPROACH FROM THE WEST WITH THE WARM FRONT TO THE
SOUTH PUSHING ONLY SLOWLY NORTHWARD. MODELS DIFFER ON THE
DEVELOPMENT OF A SURFACE LOW ALONG THE FRONT. PRECIPITABLE WATER WILL
BE ON THE INCREASE WITH VALUES REACHING GREATER THAN 1.5 INCHES
ACROSS PORTIONS OF THE REGION BY FRIDAY NIGHT / SATURDAY. ELEVATED
INSTABILITY WILL ALSO INCREASE AS THE CLOSED UPPER LOW AND SOUTHWARD
EXTENDING UPPER LEVEL TROUGH APPROACHES. SCATTERED THUNDERSTORMS CAN
BE EXPECTED BY FRIDAY NIGHT AND CONTINUING INTO SATURDAY / SATURDAY
NIGHT. RAIN MAY BE LOCALLY HEAVY...HELD OFF MENTIONING THIS THREAT
IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW UNTIL CONFIDENCE INCREASES.
IT IS POSSIBLE THUNDERSTORMS TO OUR SOUTH COULD CUT US OFF FROM THE
GREATER MOISTURE AND RAINFALL. THE UPPER LEVEL TROUGH / ASSOCIATED
COLD FRONT IS FORECAST THROUGH THE REGION SATURDAY NIGHT WITH A
LINGERING CHANCE OF RAIN SUNDAY.
JCL
&&
.AVIATION...
06Z TAF CYCLE
IFR TO MVFR CIGS ARE EXPECTED OVERNIGHT WITH PATCHY FOG. MODEL
GUIDANCE HAS BEEN OVERLY AGGRESSIVE WITH CLEARING CLOUDS OUT FOR
SEVERAL RUNS NOW. WILL SIDE WITH THE MORE PESSIMISTIC GUIDANCE
AND KEEP CLOUDS AROUND FOR MOST OF THE DAY...ESPECIALLY AT TUP
WHERE CONDITIONS WILL LIKELY REMAIN MVFR AT BEST. PATCHY 3-5SM BR
IS POSSIBLE..ESPECIALLY TOWARD SUNRISE. CONFIDENCE IS HIGHEST
THAT JBR WILL SEE VFR CONDITIONS DURING THE AFTERNOON HOURS. MID
CLOUDS WILL RETURN TOMORROW NIGHT.
WINDS EAST TO NORTHEAST AROUND 5 KTS.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
351 PM EST MON DEC 29 2014
.SYNOPSIS...
COLD SURFACE HIGH PRESSURE WILL CONTINUE TO WEDGE DOWN FROM THE
NORTH ALONG THE APPALACHIANS TONIGHT WHILE A WEAK UPPER LEVEL
DISTURBANCE IS EXPECTED TO PASS FROM WEST TO EAST ACROSS THE AREA
TONIGHT THROUGH EARLY TUESDAY. VERY LIGHT PRECIPITATION ASSOCIATED
WITH THIS FEATURE IS EXPECTED TO CHANGE OVER TO SNOW ACROSS THE
NORTHERN PORTION OF THE REGION...WITH ACCUMULATIONS OF AN INCH OR
LESS...MAINLY ALONG AND NORTH OF U.S. 460. DRY BUT CONTINUED COLD
HIGH PRESSURE WILL BEGIN TO PUSH IN FROM THE WEST LATER TUESDAY
AND LAST UNTIL LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 350 PM EST MONDAY...
TRICKY FCST OVERNIGHT IN REGARDS TO THE AMOUNTS AND LOCATIONS OF
VERY LIGHT PRECIP AS A WEAK UPPER WAVE PASSES OVER THE DEEPENING
COLD AIR DAMMING WEDGE AS COLD SFC HIGH PRESSURE SPILLS DOWN FROM
THE NORTH. MODEL GUIDANCE ALL QUITE DIFFERENT WITH MAIN
OPERATIONAL NCEP MODELS TRENDING UPWARD SOMEWHAT WITH AS MUCH AS A
QUARTER TO TWO THIRDS OF AN INCH LIQUID EQUIV...MAINLY OVER
THE WESTERN PORTIONS. EVEN ORIGINALLY DRIER GFS NOW AS MUCH AS
FOUR TENTHS OF AN INCH OVER THE ALLEGHANY HIGHLANDS. MEANWHILE
CONVECTIVE-ALLOWING MODELS GENERALLY LESS THAN TWO TENTHS OF AN
INCH. AM LEANING ON THE LIGHT SIDE OF THE QPF OPTIONS...MORE IN
LINE WITH IDEA OF MOST OF THE HRRR RUNS...AND POSSIBILITY THAT
MORE OF THE PRECIP ACTUALLY ENDS UP BACK ACROSS THE FOOTHILLS AND
PIEDMONT AGAIN. AM LEAVING SOME VERY LOW LIKELY POPS FOR TONIGHT
ACROSS PARTS OF THE MOUNTAINS...WITH HIGHER CHANCE POPS NOW ACROSS
THE FOOTHILLS. THE ISSUE OF MOISTURE DEPTH IS STILL CONCERN AS
WELL...AND WHILE I DID NOT INCLUDE ANY DRIZZLE IN THE
GRIDS...THERE COULD VERY WELL BE PERIODS OF TIME AND PORTIONS OF
THE AREA WHERE WE SEE MORE DRIZZLE DUE TO LACK OF ICE CRYSTAL
GROWTH ALOFT. THIS WOULD CUT DOWN ON ANY OF THE ALREADY LIGHT
SNOW ACCUMS IF AND WHERE THIS HAPPENS. WARM NOSE DOES NOT SEEM TO
BE PRESENT IN ANY MODEL SOUNDINGS...SO GOING WITH EITHER RAIN OR
SNOW...AND SO SFC TEMPS WILL BE THE KEY TO THAT CHANGEOVER. AS FAR
AS THE TEMPS GO...ALREADY GETTING COLDER THIS AFTERNOON THAN WE
EARLIER ANTICIPATED...AND SOME HIGHER ELEVATIONS HAVE REPORTS
SOME VERY LIGHT SNOW. THUS LOWERED TEMPS THROUGH EVENING AND
OVERNIGHT A FEW DEGREES FROM PREVIOUS FORECAST WHERE WEDGE IS
EXPECTED TO BE THE STRONGEST...AND THIS RESULTS IN A SLIGHTLY
EARLIER CHANGEOVER FROM LIGHT RAIN TO LIGHT SNOW...BUT EXCEPT FOR
HIGHER ELEVATIONS...THIS WILL STILL BE AFTER MIDNIGHT.
BOTTOM LINE IS ONLY VERY LIGHT AMOUNTS OF SNOW ACCUM
EXPECTED LATE TONIGHT AND IN THE EARLY MORNING HOURS TUESDAY...AND
IT WILL LIKELY HAVE TROUBLE STICKING AS WELL EXCEPT FOR HIGHEST
ELEVATIONS. HAVE DUSTING TO LESS THAN AN INCH GENERALLY NORTH OF
U.S. 460...AND DOWN THE BLUE RIDGE TO NEAR MEADOWS OF DAN. MAYBE
AN INCH TO ALMOST TWO ALONG HIGHEST RIDGES OF ALLEGHANY HIGHLANDS
AND ALONG BLUE RIDGE PARKWAY NORTH OF PEAKS OF OTTER. MOST ROADS
NOT EXPECTED TO SEE ANY ACCUMULATION.
ANY LINGERING PRECIP EVAPORATES QUICKLY BY MIDDAY TUESDAY AS
SHORT WAVE PASSES BY AND DRIER AIR FROM NORTH CONTINUES TO FILTER
IN. WESTERLY FLOW AT RIDGE TOP LEVEL DEVELOPS BUT VERY WEAK FLOW
AND LITTLE MOISTURE TO WORK WITH SO NO ISSUES WITH ANY UPSLOPE
SNOW SHOWERS IN FAR WEST IT APPEARS. MAX TEMPS MAY BE TRICKY WITH
SOME SUNSHINE LATE IN THE DAY...BUT THIS COULD BE TOO LATE FOR LOW
SUN ANGLE TO HAVE MUCH IMPACT...SO FOR NOW GOING ON COLD SIDE OF
GUIDANCE WITH ONLY ABOUT A 5-7 DEGREE RISE FROM OVERNIGHT LOWS.
ABOVE FREEZING BY LATE MORNING SO ANY MINOR AMOUNTS OF SNOW THAT
DOES FALL WILL BE GONE BY NOON MOST LIKELY.
FINALLY...COLD WEDGE WILL KEEP SOME AREAS OF FOG AND LOW CEILINGS
AROUND...MOST ESPECIALLY NEAR THE BLUE RIDGE...BUT ALSO SOME OF
THE MTN VALLEYS AS WELL...SO BLANKED THE FOOTHILLS AND WESTWARD
WITH PATCHY FOG THROUGH TOMORROW MORNING IN THE FORECAST GRIDS BUT THIS
MAY LINGER THROUGH MUCH OF THE DAY IN SPOTS UNTIL THE WEAK WESTERLY
FLOW CAN PUSH EAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 200 PM EST MONDAY...
A LARGE AREA OF HIGH PRESSURE WILL BUILD SOUTH FROM THE ROCKIES LATE
TUESDAY...THEN INTO THE SOUTHEAST U.S. BY THURSDAY EVENING KEEPING
DRY WEATHER FOR OUR AREA DURING THIS PORTION OF THE FORECAST.
ADJUSTED TEMPS DOWN A FEW DEGREES WEDNESDAY MORNING AND WEDNESDAY
AFTERNOON UNDER GOOD COLD AIR ADVECTION. BY THURSDAY MORNING
MODELS ARE IN GOOD AGREEMENT THAT SFC HIGH NOSES INTO OUR
AREA ALLOWING VALLEY WINDS TO DIMINISH. THIS COMBINED WITH THE
DRY AIR MASS IN PLACE SHOULD ALLOW TEMPS TO DROP BELOW GUIDANCE
VALUES. THE EXCEPTION WILL BE ON THE RIDGETOPS WHERE 850MB WINDS
WILL KEEP TEMPS WARMER.
HEIGHTS RISE ON THURSDAY AS AN UPPER RIDGE BEGINS TO BUILD IN THE
CENTRAL U.S. IN ADVANCE OF A SOUTHWEST U.S. UPPER LOW.
THIS...COMBINED WITH DOWNSLOPING WINDS...SHOULD ALLOW FOR A NICE
RECOVERY IN TEMPS THURSDAY. WENT A DEGREE OR TWO ABOVE GUIDANCE FOR
HIGHS.
ONLY OTHER CHANGE TO THE FORECAST WAS TO INCREASE THE WINDS ABOVE
3500 FEET WEDNESDAY AND THURSDAY AS A SWIFT MOVING NORTHERN STREAM
SHORTWAVE PASSES THROUGH THE EASTERN GREAT LAKES THROUGH NEW ENGLAND
DURING THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 235 PM EST MONDAY...
DRY AND SEASONABLY COOL WEATHER IS EXPECTED OVER THE BLACKSBURG
FORECAST AREA FRIDAY MORNING AS A WEAK SHORT WAVE IN NORTHERN STREAM
SCOOTS EAST THROUGH NEW ENGLAND...WITH COOL HIGH PRESSURE BUILDING
SOUTHWESTWARD IN ITS WAKE.
HOWEVER...MUCH OF THE REST OF THE LONG TERM FORECAST FROM FRIDAY
AFTERNOON INTO MONDAY APPEARS TO BE MUCH MORE UNCERTAIN...WITH
SIGNIFICANT AND PERSISTENT DISPARITY EXISTING BETWEEN THE LONGER-
TERM MODELS IN REFLECTING STRENGTH AND PLACEMENT OF NORTHERN
STREAM...AND ITS INFLUENCE ON SOUTHERN STREAM CLOSED LOW SOUTH OF
THE FOUR CORNERS AREA ON FRIDAY AFTERNOON THAT IS FORECAST TO
GRADUALLY LIFT NORTHEAST AND FILL AS IT PROGRESSES FROM THE SOUTHERN
PLAINS UP THROUGH THE OHIO VALLEY OVER THE WEEKEND.
ECMWF MAINTAINS A MORE PERSISTENT CLOSED UPPER LOW THAT IS MUCH LESS
AMPLIFIED...YET LESS PROGRESSIVE AND FURTHER SOUTH...RESULTING IN
INCREASING ISENTROPIC LIFT AND RAIN MOVING INTO AT LEAST THE
SOUTHWESTERN HALF OF THE BLACKSBURG FORECAST AREA BY/DURING FRIDAY
AFTERNOON...BUT NOT ENDING UNTIL PASSAGE OF OPENING/WEAKENING UPPER
TROF ON SUNDAY NIGHT.
GFS...WHICH REFLECTS A MORE AMPLIFIED...YET EVENTUALLY MORE
PROGRESSIVE AND NORTHERN SYSTEM PLACEMENT...HOLDS BACK RAIN SHIELD
UNTIL SATURDAY DUE TO INFLUENCE OF LARGER AND STRONGER DRY SURFACE
HIGH PRESSURE SYSTEM OVER NEW ENGLAND. GFS ALSO THE COLDER OF THE
LONGER RANGE SOLUTIONS...SINCE STRONGER SURFACE RIDGE TO NORTHEAST
WOULD LOCK COOL-WEDGE IN PLACE OVER THE BLACKSBURG FORECAST AREA.
HOWEVER...BEING MORE PROGRESSIVE...RAIN EVENT ENDS A BIT EARLIER
THAN ECMWF SOLUTION...ON SUNDAY AFTERNOON WITH PASSAGE OF UPPER
TROF...BUT WITH PERHAPS SOME COLD ADVECTION UPSLOPE PRECIPITATION
CONTINUING ACROSS THE WESTERN FLANKS OF THE APPALACHIANS UNTIL
AROUND DAYBREAK MONDAY.
BOTH MODELS HAVE BEEN INCONSISTENT IN TIMING AND PLACEMENT OF SYSTEM
THOUGH THIS TIMEFRAME FOR AT LEAST THE PAST SEVERAL RUNS...WHICH IS
NOT ALL THAT SURPRISING CONSIDERING ACTIVE NORTHERN STREAM CLASHING
WITH INITIALLY CLOSED AND STAGNANT SOUTHERN STREAM SYSTEM...SO MODEL
BLEND/ENSEMBLE APPROACH BEST TO APPLY FOR LONG TERM FORECAST UNTIL
CONFIDENCE INCREASES IN MOVING TOWARD ANY PARTICULAR SOLUTION.
NEITHER MODEL INDICATING THAT THICKNESSES WILL BE ESPECIALLY
CRITICAL FOR P-TYPE ISSUES...MEANING A MAINLY WET RATHER THAN WHITE
FORECAST OVER THE WEEKEND. HOWEVER...IF COLDER GFS SOLUTION
VERIFIES...THICKNESSES MAY BE CLOSE ENOUGH TO CRITICAL VALUES NORTH
OF HIGHWAY 64 TO WARRANT AT LEAST A NOMINAL INSERTION OF A P-TYPE
MIX DURING TIME OF PRECIPITATION ONSET...AND PERHAPS FOLLOWING
PASSAGE OF MAIN SYSTEM IN THE NORTHWESTERN MOUNTAINS ON SUNDAY NIGHT
PROVIDED THAT POST FRONTAL COLD ADVECTION IS SUFFICIENTLY STRONG.
REGARDLESS OF TIMING AND PLACEMENT DIFFERENCES...ALL LONGER RANGE
MODELS INDICATE THAT MONDAY WILL BE DRY FOLLOWING PASSAGE OF THE
MAIN UPPER SYSTEM...WITH ANY ADDITION SOUTHERN STREAM ENERGY LIKELY
TO BE DEFLECTED TO OUR SOUTH AS NORTHERN STREAM TROFING GRADUALLY
STRENGTHENS AND AMPLIFIES FROM THE UPPER GREAT LAKES EAST INTO THE
NORTHEASTERN PORTION OF THE NATION FROM MONDAY INTO THE MID WEEK
PERIOD.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM EST MONDAY...
IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE AT ALL AIRPORTS
THROUGH AT LEAST TONIGHT...AND FOR WESTERN AIRPORTS EVEN INTO
EARLY PART OF TUESDAY...UNDER THE INFLUENCE OF COLD AIR DAMMING
WHICH IS ONLY STRENGTHENING WITH TIME. KLYH CURRENTLY MVFR BUT
EXPECTED TO DROP TO IFR BY EARLY EVENING IF NOT SOONER. LOW
CONFIDENCE IN WHEN CONDITIONS MAY BEGIN TO BREAK OUT AND LIFT
EARLY TUESDAY...AND MAY HAPPEN AT KBLF SOONER THAN TAF CURRENTLY
INDICATES. MORE CONFIDENT THAT KROA AND KLYH WILL IMPROVE TO AT
LEAST MVFR DURING TUESDAY MORNING AS DRIER AIR CONTINUES TO FILTER
DOWN FROM NORTH...AND EVENTUALLY KDAN AS WELL BEFORE 18Z.
IN ADDITION...ALL AIRPORTS EXCEPT FOR KDAN SHOULD SEE SOME VERY
LIGHT RAIN CHANGE TO LIGHT SNOW AFTER MIDNIGHT...BUT NOT EXPECTED
TO STICK MUCH AT ALL EXCEPT FOR THE HIGHER ELEVATION AIRPORTS SUCH
AS KLWB...AND KBCB. NOT SURE IT WILL BE COLD ENOUGH TO REALLY
STICK AT KBLF AND KROA OR KLYH. KDAN LIKELY WILL NOT EVEN SEE
CHANGEOVER. IN ANY CASE...SNOW AMOUNTS WOULD ONLY APPROACH AN INCH
IN THE WORSE CASE SCENARIO.
EXTENDED DISCUSSION...
A LARGE AREA OF HIGH PRESSURE WILL START TO NOSE INTO THE AREA
FROM THE WEST LATER TUESDAY INTO WEDNESDAY. THIS WILL RESULT IN
GRADUAL CLEARING...CLOUD BASES LIFTING INTO THE MVFR CATEGORY
TUESDAY AFTERNOON AND TUESDAY NIGHT...BEFORE DISSIPATING WEDNESDAY
AND RETURN OF VFR. VFR WILL THEN PREVAIL THROUGH AT LEAST THURSDAY
BEFORE TRENDING DOWN AGAIN FOR THE WEEKEND PER RETURN OF MOISTURE
FROM THE SOUTHWEST. THE NEXT LOW PRESSURE SYSTEM TO AFFECT THE
AREA WILL COME FROM THE SOUTHWEST...LOW PRESSURE DEVELOPING ALONG
THE TEXAS GULF COAST FRIDAY...THEN MOVING NORTHEAST ACROSS THE MID
ATLANTIC REGION FOR THE WEEKEND. THIS SYSTEM LOOKS LIKE IT WILL
PRODUCE A MULTI-DAY PERIOD OF SUB-VFR CONDITIONS...BEGINNING AS
EARLY AS FRIDAY NIGHT...AND LINGERING THROUGH THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK
SHORT TERM...PH
LONG TERM...WERT
AVIATION...PM/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
101 PM EST MON DEC 29 2014
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDS FROM THE TIDEWATER OF VIRGINIA TO THE
FLORIDA PANHANDLE. ONE WAVE OF LOW PRESSURE WAS PULLING AN AREA OF
WIDESPREAD RAIN INTO EASTERN VIRGINIA AND NORTH CAROLINA. MEANWHILE...
COLDER AIR WILL FILTER INTO THE REGION FROM THE NORTH THIS
AFTERNOON INTO TUESDAY. A WEAK UPPER LEVEL DISTURBANCE IS
EXPECTED TO PASS FROM WEST TO EAST ACROSS THE AREA TONIGHT THROUGH
EARLY TUESDAY. THIS FEATURE MAY BRING A LIGHT WINTRY MIX OF
PRECIPITATION TO PARTS OF THE AREA...WITH THE POTENTIAL FOR AN
INCH OR TWO OF SNOW ACROSS THE VIRGINIA AND WEST VIRGINIA
HIGHLANDS.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1200 PM EST MONDAY...
SOME UPWARD ADJUSTMENTS TO POPS FOR REST OF AFTERNOO BASED ON
LATEST RADAR TRENDS OF SOME LIGHT DEVELOPMENT ACROSS NORTH
CAROLINA AND SNEAKING INTO SOUTHSIDE VIRGINIA...WHICH HRRR SEEMS
TO HAVE PRETTY GOOD HANDLE ON. LEAVING CHANCE TO LOW LIKELY BACK
IN WEST DUE TO EXPECTED REDEVELOPMENT OF ANOTHER AREA LATER THIS
AFTERNOON AS ISENTROPIC LIFT INCREASES A LITTLE. ALREADY GETTING
SOME DRIZZLE IN MANY MTN AREAS. TEMPS ACROSS THE NORTH AND
NORTHEAST CONTINUE TO SLOWLY DROP AS SHALLOW COLDER AIR SURGES
IN...SO MADE SOME MORE ADJUSTMENTS DOWNWARD THERE AS WELL.
PREV DISCUSSION AS OF 1010 AM EST MONDAY...
MAIN SWATH OF RAIN ASSOCIATED WITH THE MOST RECENT SHORT WAVE TO
PASS ACROSS OUR AREA IS NOW PULLING EAST OF THE FCST AREA THIS
MORNING...WITH LOW CLOUDS AND SOME PATCHY FOG BEHIND IT AS COOL
AIR BEGINS TO FILTER DOWN FROM THE NORTHEAST MOISTURE LINGERS
BEHIND THE AREA OF RAIN. ALL MODELS CONTINUE TO SHOW SOME VERY
LIGHT PRECIP LATER THIS AFTERNOON...MAINLY IN THE MTNS...AS WEAK
ISENTROPIC LIFT MOVES BACK IN AHEAD OF ANOTHER VERY WEAK SHORT
WAVE AND THE LINGERING LOW LEVEL MOISTURE. THINK SOME MODELS MAY
BE OVERDOING THE PRECIP...BUT STILL EXPECT AT LEAST A FEW
HUNDREDTHS...SO AM KEEPING CHC POPS INCREASING TO LOW LIKELY FOR
MANY AREAS IN THE MTNS AS THE AFTERNOON PROGRESSES AND THE WEDGE
SPREADS FARTHER SOUTHWEST SO LIFT INCREASES A LITTLE. FOR
REMAINDER OF AFTERNOON...DROPPING POPS IN EAST TO LOW CHC GIVEN
SOME VERY WEAK ISENTROPIC LIFT MAY CONTINUE OUT THERE...BUT MAY
ULTIMATELY NEED TO DROP POPS THERE LATER.
MADE A FEW TWEAKS TO TEMPS AND WINDS IN THE EAST MAINLY AS SURGE
OF BACK DOOR COOLER AIR ALREADY STARTING...BUT TEMPS INITIALLY
WILL NOT DROP TOO MUCH...UNTIL LATE THIS AFTERNOON AND EVENING.
CERTAINLY WILL NOT RISE THOUGH.
PREV DISCUSSION AS OF 430 AM EST MONDAY...
A COLD FRONT SLIPPED THROUGH THE AREA LATE SUNDAY AND IS NOW
SLOWLY DRIFTING TOWARD THE MID ATLANTIC COAST. A WAVE OF LOW
PRESSURE WAS RIPPLING NORTHEAST ALONG THE FRONT...PROVIDING AREAS
MAINLY SOUTH OF INTERSTATE 81 WITH A WIDESPREAD WETTING RAIN...QPF
OF A THIRD /0.33/ TO TWO THIRDS /0.66/ OF AN INCH. NORTH OF
I-81 THE RAIN WAS NOT SO WIDESPREAD...AND AMOUNTS WILL LIKELY
AVERAGE LESS THAN A TENTH OF AN INCH.
ONCE THE WAVE PASSES LATER THIS MORNING...RAIN SHOULD END OR
TAPER TO DRIZZLE. CLEARING IS NOT ANTICIPATED PER THE DEVELOPMENT
OF NORTHEASTERLY LOW LEVEL WINDS WHICH WILL KEEP CLOUDS BANKED
AGAINST THE EAST SIDE OF THE APPALACHIANS. TEMPERATURES TODAY WILL
BE STEADY OR FALLING...COOLER AIR INFILTRATING THE AREA FROM THE
NORTH OR NORTHEAST AND COUNTERING ANY SORT OF DIURNAL TEMPERATURE
RISE.
WHILE THE MAIN SURFACE FRONT WILL BE WELL TO THE SOUTHEAST OF THE
AREA TONIGHT...THE COMBINATION OF A SECONDARY SURGE OF SHALLOW
COLDER AIR SPILLING DOWN FROM THE NORTH AND NORTHEAST...ALONG WITH
A VERY WEAK UPPER WAVE PASSING OVER FROM THE WEST...WILL CREATE
SOME WEAK ISENTROPIC LIFT OVER THE APPALACHIANS OVERNIGHT AND
LASTING INTO AT LEAST PART OF TUESDAY. MOISTURE IS SHALLOW AND
STRUGGLES TO GET INTO THE ICE CRYSTAL GROWTH ZONE. BOTH THE GFS
AND NAM DO INDICATE A 4 TO 8 HOUR WINDOW LATE TONIGHT INTO EARLY
TUESDAY WHERE SOME ICE CRYSTAL GROWTH TAKES PLACE...BOTH MODELS
SPITTING OUT A TENTH TO TWO TENTHS OF AN INCH OF QPF.
SO THE FORECAST CHALLENGE FOR LATE TONIGHT AND EARLY TUESDAY IS
WEATHER THE PRECIPITATION THAT DEVELOPS FALLS AS DRIZZLE/FREEZING
DRIZZLE...OR AS LIGHT RAIN/LIGHT SNOW. TEMPERATURES TONIGHT AT THE
SURFACE ARE FORECAST TO REACH FREEZING ALONG AND NORTH OF ROUTE
460. THIS WOULD BE THE GENERAL REGION WHERE THE FREEZING DRIZZLE
OR LIGHT SNOW WOULD OCCUR. SOUTH OF 460...THE BOUNDARY LAYER WOULD
MOST LIKELY REMAIN WARM ENOUGH TO SUPPORT DRIZZLE/LIGHT RAIN.
SINCE BOTH THE GFS AND NAM ARE IN GENERAL AGREEMENT THAT A PERIOD
OF LIGHT PRECIP WILL OCCUR...WILL ERR ON THE SIDE OF CAUTION AND
FORECAST AT LEAST A TENTH OF AN INCH OF QPF. FOR AREAS WHERE
TEMPERATURES ARE COLD ENOUGH...MAINLY NORTH OF HIGHWAY 460...THIS
QPF WILL FALL AS LIGHT SNOW OR A MIXTURE OF RAIN AND SNOW. THE
HIGHER ELEVATIONS...HIGHLANDS OF VA/WV...WOULD HAVE THE BEST
CHANCE FOR SEEING SOMETHING THAT WOULD ACCUMULATE...OUR GRIDDED
FORECAST REFLECTING 1-2 INCHES OF SNOW FOR ELEVATIONS ABOVE 2500
FEET. SINCE ACCUMULATIONS ARE NOT EXPECTED TO EXCEED 2 INCHES...NO
HEADLINES PLANNED ATTM.
THE ISENTROPIC LIFT IS FORECAST TO WEAKEN BY TUESDAY
AFTERNOON/EVENING...ANY PRECIPITATION COMING TO AN END. SIMILAR TO
MONDAY...TEMPERATURES TUESDAY WILL EXPERIENCE LITTLE CHANGE
REMAINING NEARLY STEADY THROUGHOUT THE DAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 400 AM EST MONDAY...
A SHORT WAVE WILL TRACK ACROSS THE OHIO VALLEY TO THE MID ATLANTIC
COAST TUESDAY EVENING. ONCE THIS WAVE PASSES EAST...DRIER COLDER AIR
WILL FILTER INTO THE REGION OVERNIGHT. CONSIDERING THE MILD WEATHER
THE PAST COUPLE OF WEEKS...THIS COLD AIR WILL SEEM LIKE AN ARCTIC
BLAST TO SOME...BUT WE WILL ONLY BE DROPPING TEMPERATURES BACK TO
SEASONAL LEVELS. THE COLD SURFACE HIGH WILL RESIDE BACK OVER THE
PLAINS TUESDAY NIGHT AND SLOWLY MOVE EAST IN ZONAL FLOW THROUGH THE
REST OF THE WEEK. NO PRECIPITATION IS EXPECTED DURING THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM EST SUNDAY...
PERIOD BEGINS WITH SPLIT FLOW AND MODEST TROF OVER THE NORTHEAST
UNITED STATES WITH BROAD WESTERLY FLOW OVER THE FORECAST AREA AND
A CUT OFF LOW IN THE SOUTHWEST UNITED STATES. PATTERN AMPLIFIES BY
FRIDAY WITH DIGGING TROF IN THE CENTRAL UNITED STATES THAT
GENERATES A SURFACE LOW IN THE LEE OF THE ROCKIES.
MODELS SIMILAR IN THE EVOLUTION OF THE LOW THROUGH FRIDAY AND BOTH
THE ECMWF AND GFS TRACK THE LOW FROM THE MISSISSIPPI VALLEY INTO THE
GREAT LAKES. THE ECMWF IS FASTER THAN THE GFS WITH THE LOW AND COLD
FRONT. WPC STAYED CLOSE TO THE TRACK OF THE ECMWF BUT AT A SLOWER
SPEED.
SOME IN-SITU WEDGING MAY BE IN PLACE ON FRIDAY AND FRIDAY NIGHT.
SURFACE AND 850 WARM FRONT LIFT NORTH OF THE FORECAST AREA BY
SATURDAY. NO CLEAR TRENDS FOR PRECIPITATION TYPE ALTHOUGH WARMING
ALOFT SUPPORTS FREEZING RAIN/SLEET...DEPENDING ON HOW COLD
TEMPERATURES AREA AT THE SURFACE.
BEST MOISTURE AND LIFT WILL BE SATURDAY AND SATURDAY NIGHT JUST
AHEAD OF THE COLD FRONT. AT THIS TIME EXPECTING THE FRONT TO COME
THROUGH THE FORECAST AREA EARLY SUNDAY. THIS TIMING IS LIKELY TO
CHANGE AS THE SYSTEM GOES THROUGH A FEW MORE FORECAST CYCLES IN THE
MODELS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM EST MONDAY...
IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE AT ALL AIRPORTS
THROUGH AT LEAST TONIGHT...AND FOR WESTERN AIRPORTS EVEN INTO
EARLY PART OF TUESDAY...UNDER THE INFLUENCE OF COLD AIR DAMMING
WHICH IS ONLY STRENGTHENING WITH TIME. KLYH CURRENTLY MVFR BUT
EXPECTED TO DROP TO IFR BY EARLY EVENING IF NOT SOONER. LOW
CONFIDENCE IN WHEN CONDITIONS MAY BEGIN TO BREAK OUT AND LIFT
EARLY TUESDAY...AND MAY HAPPEN AT KBLF SOONER THAN TAF CURRENTLY
INDICATES. MORE CONFIDENT THAT KROA AND KLYH WILL IMPROVE TO AT
LEAST MVFR DURING TUESDAY MORNING AS DRIER AIR CONTINUES TO FILTER
DOWN FROM NORTH...AND EVENTUALLY KDAN AS WELL BEFORE 18Z.
IN ADDITION...ALL AIRPORTS EXCEPT FOR KDAN SHOULD SEE SOME VERY
LIGHT RAIN CHANGE TO LIGHT SNOW AFTER MIDNIGHT...BUT NOT EXPECTED
TO STICK MUCH AT ALL EXCEPT FOR THE HIGHER ELEVATION AIRPORTS SUCH
AS KLWB...AND KBCB. NOT SURE IT WILL BE COLD ENOUGH TO REALLY
STICK AT KBLF AND KROA OR KLYH. KDAN LIKELY WILL NOT EVEN SEE
CHANGEOVER. IN ANY CASE...SNOW AMOUNTS WOULD ONLY APPROACH AN INCH
IN THE WORSE CASE SCENARIO.
EXTENDED DISCUSSION...
A LARGE AREA OF HIGH PRESSURE WILL START TO NOSE INTO THE AREA
FROM THE WEST LATER TUESDAY INTO WEDNESDAY. THIS WILL RESULT IN
GRADUAL CLEARING...CLOUD BASES LIFTING INTO THE MVFR CATEGORY
TUESDAY AFTERNOON AND TUESDAY NIGHT...BEFORE DISSIPATING WEDNESDAY
AND RETURN OF VFR. VFR WILL THEN PREVAIL THROUGH AT LEAST THURSDAY
BEFORE TRENDING DOWN AGAIN FOR THE WEEKEND PER RETURN OF MOISTURE
FROM THE SOUTHWEST. THE NEXT LOW PRESSURE SYSTEM TO AFFECT THE
AREA WILL COME FROM THE SOUTHWEST...LOW PRESSURE DEVELOPING ALONG
THE TEXAS GULF COAST FRIDAY...THEN MOVING NORTHEAST ACROSS THE MID
ATLANTIC REGION FOR THE WEEKEND. THIS SYSTEM LOOKS LIKE IT WILL
PRODUCE A MULTI-DAY PERIOD OF SUB-VFR CONDITIONS...BEGINNING AS
EARLY AS FRIDAY NIGHT...AND LINGERING THROUGH THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/SK
NEAR TERM...PM/SK
SHORT TERM...RCS
LONG TERM...AMS
AVIATION...PM/SK